Comparison of skin changes induced on mice by either group A type 12 or group G streptococci. Adult Swiss webster mice were injected with 3 x 10(6) colony-forming units (cfu) of group G or 2.5 x 10(6) cfu of group A streptococci at intradermal injection sites on the right and left paralumbar areas of the back. The mice were sacrificed at intervals between 4 hours and 14 days post-injection (p.i.) and full thickness biopsies of skin 10 mm in diameter encompassing the sites of injection were taken. One tissue specimen was homogenized in PBS and plated to determine the number of cfu, while another was used for histopathological studies. The number of viable group A and group G streptococci in the tissue increased to 3 x 10(9) cfu by 96 hours p.i.: after 192 hours p.i. the group A cells had declined to 2.7 x 10(6) cfu compared to 1.1 x 10(8) cfu for group G cells. No streptococci of either group were detected at 336 hours (14 days p.i.). Gross edematous lesions induced by either streptococcus group were evident on all animals at 24 hours (p.i.). Group G streptococci lesions were larger and persisted longer than lesions induced by group A. Histological examination consistently revealed more inflammation and necrosis in tissue sections from mice injected with group G streptococci.


Mapping the genes that made maize.

Mapping the genes that made maize. George Beadle proposed that the striking morphological differences between cultivated maize and its probable wild progenitor (teosinte) were initiated by a small number of mutations with large effects on adult morphology. Recent genetic analyses using molecular markers provide some support for this view and show where in the maize genome the putative loci are likely to be located. This work sets the stage for fine-scale linkage mapping of these genomic regions and the eventual cloning of the genes involved in this remarkable evolutionary transformation.


Master genes in mammalian repetitive DNA amplification. The analysis of species-specific subfamilies of both the LINE and SINE mammalian repetitive DNA families suggests that such subfamilies have arisen by amplification of an extremely small group of 'master' genes. In contrast to the master genes, the vast majority of both SINEs and LINEs appear to behave like psudogenes in their inability to undergo extensive amplification.


Secretion across the bacterial outer membrane. Many bacteria secrete extracellular proteins such as hydrolytic enzymes or toxins. In Gram-negative bacteria, secreted proteins must cross the two membranes that constitute the cell envelope. Recent studies have identified several specific secretion systems that can be classified in three distinct pathways, and related systems have been discovered in a wide range of prokaryotic and eukaryotic cells.


Ordering gene function: the interpretation of epistasis in regulatory hierarchies. The order of action of genes in a regulatory hierarchy that is governed by a signal can often be determined by the method of epistasis analysis, in which the phenotype of a double mutant is compared with that of single mutants. The epistatic mutation may be in either the upstream or the downstream gene, depending on the nature of the two mutations and the type of regulation. Nevertheless, when the regulatory hierarchy satisfies certain conditions, simple rules allow the position of the epistatic locus in the pathway to be determined without detailed knowledge of the nature of the mutations, the pathway, or the molecular mechanism of regulation.


Regenerating good sense: RNA editing and trans splicing in plant mitochondria. The protein products of plant mitochondrial genes cannot be predicted accurately from genomic sequences, since RNA editing modifies almost all mRNA sequences post-transcriptionally. Furthermore, RNA editing alters leader, trailer and intron sequences, and may be required for processing of these sequences. For several plant mitochondrial transcripts, processing includes trans splicing, which connects exons scattered throughout the genome. The mature transcripts are assembled via split group II intron sequences.


Localization of methanol dehydrogenase in two strains of methylotrophic bacteria detected by immunogold labeling. Antibodies to methanol dehydrogenase purified from Methylobacterium sp. strain AM1 and Methylomonas sp. strain A4 were raised. The antibody preparations were used in indirect immunogold labeling studies. With this approach, methanol dehydrogenase was found to be preferentially localized to the periplasmic region of the methylotroph Methylobacterium sp. strain AM1 and to the intracytoplasmic membrane of the methanotroph Methylomonas sp. strain A4. Antibody cross-reactivity to other methylotrophic bacteria was detected.


Toxicity and carcinogenicity of hydroquinone in F344/N rats and B6C3F1 mice. Toxicology and carcinogenesis studies were conducted by administering hydroquinone (more than 99% pure) by gavage to groups of F344/N rats and B6C3F1 mice of each sex for 14 days, 13 wk or 2 yr. 14-day studies were conducted by administering hydroquinone in corn oil to rats at doses ranging from 63 to 1000 mg/kg body weight and to mice at doses ranging from 31 to 500 mg/kg, 5 days/wk. In the 13-wk studies, doses for rats and mice ranged from 25 to 400 mg/kg. At those doses showing some indication of toxicity in the 14-day and 13-wk studies, the central nervous system, forestomach and liver were identified as target organs in both species and renal toxicity was observed in rats. Based on these results, 2-yr studies were conducted by administering 0, 25 or 50 mg hydroquinone/kg in deionized water by gavage to groups of 65 rats of each sex, 5 days/wk. Groups of 65 mice of each sex were given 0, 50 or 100 mg/kg on the same schedule. 10 rats and 10 mice from each group were killed and evaluated after 15 months. Mean body weights of high-dose male rats and high-dose mice were approx. 5-14% lower than those of controls during the second half of the study. No differences in survival were observed between dosed and control groups of rats or mice. Nearly all male rats and most female rats in all vehicle control and exposed groups had nephropathy, which was judged to be more severe in high-dose male rats. Hyperplasia of the renal pelvic transitional epithelium and renal cortical cysts were increased in male rats. Tubular cell hyperplasia of the kidney was seen in two high-dose male rats, and renal tubular adenomas were seen in 4/55 low-dose and 8/55 high-dose male rats; none was seen in vehicle controls or in female rats. Mononuclear cell leukaemia in female rats occurred with increased incidences in the dosed groups (vehicle control, 9/55; low dose, 15/55; high dose, 22/55). Compound-related lesions observed in the liver of high-dose male mice included anisokaryosis, syncytial alteration and basophilic foci. The incidences of hepatocellular neoplasms, primarily adenomas, were increased in dosed female mice (3/55; 16/55; 13/55). Follicular cell hyperplasia of the thyroid gland was increased in dosed mice.(ABSTRACT TRUNCATED AT 400 WORDS)


Simultaneous recording of the release of nigral and striatal dopamine in the awake rat. The extracellular concentration of dopamine (DA) and 3,4-hydroxyphenylacetic acid (DOPAC) were estimated in the substantia nigra and striatum by microdialysis. The dialysate content of DA increased at least 10-fold when nomifensine (5 mumol/l) was infused into the nigra via the dialysis membrane. To improve the analytical chemical detection of DA, nomifensine was infused continually during all the dialysis experiments that were carried out in the substantia nigra. Dendritic as well as terminal release of DA were inhibited for several hours when the nerve impulse flow in dopaminergic neurons was blocked by systemic administration of gamma-butyrolacton (750 mg/kg, i.p.). Perfusion of tetrodotoxin through the nigra (1 mumol/l) produced a complete disappearance of nigral DA release and a somewhat variable decrease in the release of striatal dopamine. When tetrodotoxin was infused into the nigra, the DOPAC output from the nigra was unchanged, but striatal DOPAC increased to about 300% of controls. These results show that the dendritic release of DA fulfills classical release criteria: it possesses an effective uptake-mechanism, it is dependent on the opening of fast-sodium channels and it is related to drug-induced changes in impulse-flow activity.


Highlights of D1 dopamine receptor antagonist research. SCH 39166 is now undergoing clinical trials in schizophrenics as a selective D1 dopamine receptor antagonist. It differs from SCH 23390, the prototype D1 receptor antagonist, by having reduced affinity for serotonin receptors and a longer duration of action in primates, as measured in the squirrel monkey conditioned avoidance paradigm. Further studies on this difference in primates indicates that it may be attributable to reduced affinity of SCH 39166 compared to SCH 23390 for the hepatic glucuronosyltransferase system. Their affinities are similar in rats, a species in which both have similar duration of action. These and other studies presented are consistent with the novel profile of SCH 39166.


CNS distribution of D1 receptors: use of a new specific D1 receptor antagonist, [3H]SCH39166. D1 dopamine receptors have been localized using a radioactive form of a new specific antagonist, [3H]SCH39166. This compound has been shown, in in vitro binding studies, to be highly selective for the D1 receptor subtype; more so than its predecessor, [3H]SCH23390. These ligand binds saturably, reversibly and with high affinity. Use of appropriate conditions produces a high signal to noise binding ratio to D1 receptors in slide-mounted tissue sections. Autoradiographic localization of radiolabeled receptors shows high densities of the D1 receptor subtype in such brain structures as the caudate-putamen, nucleus accumbens, entopeduncular nucleus, and the substantia nigra pars reticulata. A lower density of receptors is found in a few other areas including lamina VI of the cerebral cortex. A distinct paucity of binding was apparent in lamina IV of the cerebral cortex and in the choroid plexus, two areas thought to have D1 receptors. SCH39166 thus represents a superior ligand for obtaining selective labeling of D1 receptors in autoradiographic and binding studies.


New classes of selective D-1 dopamine receptor antagonist provide further evidence for two directions of D-1:D-2 interaction. Initial notions of cooperative/synergistic interactions between D-1 and D-2 dopamine receptors have been followed by recent evidence suggesting more complex forms of D-1:D-2 interaction. Each of the new, putative selective D-1 antagonists SCH 39166, NO 756 and A-69024 antagonised typical behavioural responses to the selective D-2 agonist RU 24213 and concurrently released atypical behaviour. These data extend new notions of both cooperative/synergistic and oppositional D-1:D-2 interactions in the regulation of typical and atypical behaviours, which may involve further subtypes of D-1 and of D-2 receptor.


SCH 39166, a potential antipsychotic drug, does not evoke movement disorders in cebus monkeys. Subchronic administration of a neuroleptic in cebus monkeys can reliably mimic the abnormal movements produced by these drugs in humans. SCH 39166 is the best candidate to test in this model to determine if selective antagonism at the dopamine D1 receptor is devoid of these side effects. It has superior selectivity for the dopamine D1 site versus several other sites and a significantly longer duration in primates than the prototypical D1 antagonist, SCH 23390. In contrast to haloperidol, weekly administration of SCH 39166 for 14 weeks did not produce abnormal movements but did produce equivalent sedative effects. Thus dopamine D1 antagonists are uniquely different from D2 antagonists with regards to the production of abnormal movements.


Dopamine D1 and opioid receptor binding changes in the limbic system of sleep deprived rats. Sleep deprivation induced by the platform technique is considered to be a heavy stressful situation in rats. At the end of the sleep deprivation period (72 h) the rat displayed particular behavior characterized by wakefulness, a high degree of motor and exploratory activity, increased alertness and reactivity to environmental stimuli. Our previous results indicated that this behavior was potently antagonized by the administration of the D1 selective antagonist SCH 23390 and by the opioid antagonist naloxone. In this paper we show that concomitantly to this behavior, an increased number of D1 receptors associated with an increased dopamine-stimulated adenylate cyclase activity is present in the limbic system but not in the striatum of these animals. On the contrary, a decreased Bmax of mu and delta opioid receptors was found in the same brain area. These data suggest an active role of limbic dopamine and opioid systems in the generation of arousal and insomnia related to sleep deprivation-induced stress.


A68930: a potent agonist specific for the dopamine D1 receptor. A68930, [1R, 3S] 1-aminomethyl-5,6-dihydroxy-3-phenylisochroman HCl, is a potent, partial agonist in the dopamine-sensitive adenylate cyclase model of the D1 dopamine receptor in fish retina. In the rat caudate-putamen model of the D1 dopamine receptor, A68930 is a potent (EC50 2.1 nM) full agonist. In contrast, A68930 is a much weaker (EC50 = 3,920 nM) full agonist in a biochemical model of the D2 dopamine receptor. A68930 also displays weak 2 agonist activity but the molecule is virtually inactive at the 1 and beta-adrenoceptors. When tested in rats bearing a unilateral 6-OHDA lesion of the nigro-neostriatal neurons, A68930 elicits prolonged (> 20 hr) contralateral turning.


The phosphorylation state of DARPP-32, a third messenger for dopamine, is regulated by in vivo pharmacological treatments. It has been recently proposed that DARPP-32 participates, as third messenger, in the mediation of effects induced by dopamine at the cellular level. DARPP-32 is indeed localized almost exclusively on dopaminoceptive neurons bearing the D1 receptor subtype and it is phosphorylated by cAMP-dependent protein kinase. In its phospho-form, DARPP-32 acts as an inhibitor of protein phosphatase-1. In vivo pharmacological treatment with selective D1 agonists and antagonists induces changes in the phosphorylation state of DARPP-32 that can be correlated to changes in cAMP, mediated in turn by D1 and D2 receptors. These data demonstrate that the measurement of the phosphorylation state of DARPP-32 with the back-phosphorylation assay can represent a useful biochemical tool to gain further insight into the sequence of events elicited by specific dopaminergic drugs in vivo.


Differential turnover rates of D1 dopamine receptors in the brain and retina of adult and senescent rats. The present study was designed to investigate the turnover rates of D1 dopamine receptors in the brain and retina of adult and aged rats. To this aim, we monitored the increase in the density of 3H-SCH 23390 binding sites after the administration of the irreversible antagonist N-ethoxycarbonyl-2-ethoxy-1,2 dihydroquinoline (EEDQ). The results indicate that, in aged rats, the production rate of D1 receptors decreases by 41% to 61% in the striatum, nucleus accumbens and substantia nigra, whereas a smaller reduction in the degradation rate of these receptors is observed (-21% to -40%). In contrast, the production rate of D1 receptors in the retina of aged rats remains unchanged, whilst the degradation rate decreases by 25%. These alterations in the rates of receptor production and degradation may account for the age-related decrease in the density of D1 dopamine receptors in the striatum, nucleus accumbens and substantia nigra as well as for the increase in the density of these receptors in the retina of aged rats.


Dual actions of (-)-stepholidine on dopamine receptor subtypes after substantia nigra lesion. 1. It was found that the contralateral rotation challenged by (-)-SPD (4 mg/kg, ip) in 6-OHDA-lesioned rats had a gradually progressive process with long latent period and a maximal response on 63 days after lesion. This steady contralateral rotation was preferably antagonized by D-1 antagonist SCH23390 than D-2 antagonists. During its latent period (-)-SPD exhibited the antagonistic effect to APO, while during its period of full response (-)-SPD could potentiate the APO-induced rotation. 2. In the rats lesioned with kainic acid plus 6-OHDA to destroy the SNC and SNR, (-)-SPD and SKF-38393 challenged neither contralateral nor ipsilateral rotation, while APO still induced the rotation but towards ipsilateral side, just opposite to that in 6-OHDA-lesioned rats. In this case, (-)-SPD antagonized the response to APO as did SCH 23390. 3. These evidences suggest that the agonistic action of (-)-SPD is resulted from D-1 receptor subtype at the SNR under supersensitive functional state. The fact that SNR lesion could completely eliminate the agonistic action of (-)-SPD further indicate that the D-1 receptors in the ipsilateral SNR may be the sites of action of (-)-SPD. The dual actions of (-)-SPD are dependent upon the supersensitivity of D-1 receptor subtypes which render the antagonistic action to convert into the agonistic.


Quantitation of isotypes of D2 receptors using solution hybridization. Solution hybridization was used to quantitate the expression of the long and short splice variants of mRNA coding for the dopamine D2 receptor. Sequences corresponding to 450 bases of the coding region of the long form of the third intracellular loop and the full-length coding sequences of the long and short isoforms of the D2 receptor were amplified using PCR and cloned into a Bluescribe (pBS+) vector. Phage polymerases were used to synthesize riboprobes complementary to the third intracellular loop. Hybridization was carried out using sense strand RNA or total RNA isolated from tissue or cells. After hybridization and digestion with nucleases, the hybridization products were size-fractionated on a urea acrylamide gel. The RNA coding for the D2 receptor appeared as two distinct bands. One band (438 base pairs) represents the long form of the receptor and a second band (285 base pairs) represents the short form of the RNA coding for the receptor. Quantitation of the amount of RNA present suggests that in the striatum the long form of RNA coding for the receptor is expressed at higher levels than is the short form. In a cell line containing dopamine receptors derived from the pituitary (SUPI), the long form predominates to an even greater extent than in the striatum.


Heterologous monoamine reuptake: lack of transmitter specificity of neuron-specific carriers. The effect of systemic administration of desmethylimipramine (DMI), an inhibitor of the noradrenaline (NA) reuptake carrier, and of GBR 12909, an inhibitor of the dopamine (DA) reuptake carrier, on the in vivo extracellular concentrations of dopamine (DA) was studied by transcerebral dialysis in the prefrontal cortex and in the dorsal caudate of freely moving rats. In the NA-rich prefrontal cortex only DMI increased extracellular DA concentrations whereas in the dorsal caudate only GBR 12909 was effective. Haloperidol increased extracellular DA concentrations more effectively in the dorsal caudate than in the prefrontal cortex. Pretreatment with DMI, which failed to modify the effect of haloperidol in the dorsal caudate, potentiated its action in the prefrontal cortex. The reverse was obtained after GBR 12909+ haloperidol in the two areas. 6-hydroxydopamine lesioning of the dorsal NA bundle prevented the ability of DMI to increase DA concentrations. The results suggest that reuptake into NA terminals is an important mechanism by which DA is cleared from the extracellular space in a NA-rich area such as the prefrontal cortex. The elevated extracellular concentrations of DA resulting from blockade of such mechanism by tricyclic antidepressants may play a role in the therapeutic effects of these drugs.


Dopaminergic regulation of epileptic activity. We evaluated the role of dopamine systems in the propagation of epileptic Focal, limbic seizures were produced by systemically administered pilocarpine (200 mg/kg, i.p.); as previously described this dose produces limbic stereotypes but neither convulsions nor seizure-related brain damage. The systemic pretreatment with D-1, but not D-2, agonists induced convulsions identical to those produced by a higher, convulsant dose of pilocarpine (400 mg/kg). Conversely, the pretreatment with D-1 receptor antagonists prevented the convulsions whereas the D-2 antagonists facilitated the pilocarpine-induced seizures. Furthermore, we studied the effects of intracerebral injections of dopamine agents on seizures induced by pilocarpine. Nigral microinjection of D-1 agonists strongly induced motor seizures in rats treated with the low dose of pilocarpine. On the other hand, microinjection of D-1 antagonists prevented the motor seizures induced by the high dose of pilocarpine. This study indicates that the two dopamine receptor subtypes, D-1 and D-2, exert opposing roles in the control of epilepsy propagation. Substantia nigra pars reticulata appears to be primarily involved in the dopamine-mediated modulation of seizures.


Blockade of N-methyl-D-aspartate receptors potentiates dopaminergic responses in the 6-OHDA model of Parkinson: differential role of D-1 and D-2 receptors. The non competitive antagonist of N-methyl-D-aspartate (NMDA) receptors MK-801, at doses which did not produce any behavioural modification per se, increased by about 40% the contralateral turning induced by the dopaminergic (DA) D-1/D-2 agonist L-dopa in rats bearing a unilateral lesion of the DA nigro striatal neurons. Administration of MK-801 in combination with selective agonists of the D-1 (SKF 38393) or D-2 (LY 171555) receptor, induced an increase of about 280% of D-1 mediated turning and a 70% decrease of D-2 mediated turning. Analysis of the potentiation of L-dopa mediated turning by MK-801 after selective D-1 receptor blockade by SCH 23390, revealed that the increase of turning was related to the stimulation of D-1 receptors by L-dopa. Immunocytochemical visualization of the proto-oncogene c-fos in the caudate-putamen (CPu) of lesioned rats, revealed a sparse c-fos positive nuclei in the lesioned CPu of rats treated with SKF 38393 alone, while after combined administration of MK-801 and SKF 38393 dense labelling of nuclei was found. The results indicate that blockade of NMDA receptors by MK-801 acts synergistically with D-1 agonists in the induction of turning after DA denervation and shows that these changes are correlated with c-fos induction in specific areas of the CPu.


Selective lesion of the nigrostriatal dopaminergic pathway by MPTP and acetaldehyde or diethyldithiocarbamate. We have previously reported that diethyldithiocarbamate and acetaldehyde enhance MPTP toxicity in mice (Corsini et al. 1986). Here we show that these drugs enhance the depletion of dopamine in the striatum and markedly increase MPTP-induced death of DA neurons in the substantia nigra. This enhancement of MPTP toxicity is specific for the nigro-striatal DA pathway and no recovery occurs, at least for four months after the treatment. Rats, although they show an MPTP-induced acute syndrome similar to the that induced in mice by the combined treatments, appear to be insensitive to both MPTP alone or to combined treatment with diethyldithiocarbamate or acetaldehyde. The selectivity of the permanent bilateral lesions of the nigro-striatal pathway make mice treated with acetaldehyde or diethyldithiocarbamate and MPTP a simple and reliable model for parkinsonism.


Embryonic dopaminergic neuron transplants in MPTP lesioned mouse striatum. The aim of this work is to study CNS development and plasticity, and to study the mechanisms that allow exogenous embryonic dopaminergic neurons to restore transmitter function in the experimental parkinsonism. Recently, we have developed a new method that produces a selective degeneration of the dopaminergic nigrostriatal system in mice by a combined acetaldehyde/MPTP treatment. This procedure results in a selective and irreversible loss of substantia nigra dopaminergic neurons in C57BL mice, while other dopaminergic areas of the brain are spared. MPTP alone results instead only in a temporary, reversible damage of nigro- striatal dopaminergic functions. Embryonic dopaminergic neurons from ventral mesencephalon or hypothalamus are implanted in lesioned or normal right striata or lateral ventricles. The mesencephalic neurons implanted in a lesioned host form a dense network of fibers which establish functional reinnervation of the striatum (or caudate-putamen complex). After several months about the entire striatal parenchyma appears reinnervated; on average, 20% of the grafted mesencephalic dopaminergic cells survive. Implants of embryonic HYP neurons instead, show little or no survival. Moreover, dopaminergic mesencephalic neurons in control non-lesioned animals show a poor development with little fiber outgrowth. These data indicate that interactions between embryonic dopaminergic neurons and adult striatal neurons is specific. They also suggest that this specificity is sustained by trophic and/or tropic factors possibly produced by the lesioned striatum and by putative inhibitory mechanisms of cell migration and neuritic outgrowth.


Visualization of dopamine D1, D2 and D3 receptor mRNAs in human and rat brain. Using 32P-labelled oligonucleotides derived from the coding regions of dopamine D1, D2 and D3 receptor mRNAs we localized cells containing transcripts for these receptors in the human (hD1, hD2) and rat brain (rD1, rD2, rD3). Dopamine D1 receptor mRNA was detected at high levels in neurons of the caudate and putamen as well as in the nucleus accumbens in both human and rat brain. In the rat brain D1 receptor mRNA was also abundant in the olfactory tubercles and several thalamic nuclei. In both species D1 mRNA was absent from the neurons of the substantia nigra and the ventral tegmental area as well as from the globus pallidus medialis in humans and entopeduncular nucleus in rats. In contrast, dopamine D2 receptor mRNA was found in dopaminergic neurons of the substantia nigra pars compacta and of the ventral tegmental area. In addition high levels of D2 mRNA were detected in neurons of the caudate, putamen and accumbens nuclei, the olfactory tubercle and the anterior lobe of pituitary gland. In the rat the highest level of hybridization was found in the intermediate lobe of the pituitary gland. In the rat brain dopamine D3 mRNA was mainly detected in the Islands of Calleja and at lower levels in the anterior nucleus accumbens, the medial mammillary nucleus as well as in the bed nucleus of the stria terminalis. In general, a good agreement was found between the distribution of transcripts and binding sites labelled with the D1 antagonist SCH 23390 or with the D2 ligand SDZ 205-502. For D1 receptors, the main exceptions were the absence of mRNA in the globus pallidus and the substantia nigra despite the high densities of binding sites in these regions. For D2 receptors, regions where binding sites but not mRNA were detected included the olfactory bulb, neocortex, hippocampus and superior colliculus.


Expression of rat striatal D1 and D2 dopamine receptor mRNAs: ontogenetic and pharmacological studies. The developmental characteristics of D1 and D2 dopamine receptor mRNA levels were determined by Northern blot analyses. Striatal D1 and D2 receptor mRNAs of male Fischer 344 rats were about 60% of adults levels at postnatal day 1 and reached their highest measured levels at day 30 (126-139% adults levels) and then decreased by day 120 (100%). D1 and D2 receptor densities at day 30 were about 8-fold higher than at day 1, while mRNA levels showed only a 2-fold increase. The highest level of D2 receptor mRNA in midbrain as reached at day 14 (195% adult level) while levels at day 1 were 31% higher than dose at day 120. Treatment with selective D2 receptor antagonist, haloperidol (0.5 mg/kg/day, s.c., for 2 h, 7, 14, 21 days or 21 days + 3 days withdrawal) had no effect on Sprague-Dawley rat striatal D2 receptor mRNA levels in spite of significant increases in receptor density at the later time points. However, the selective D1 receptor antagonist, SCH 23390 (0.5 mg/kg/day, s.c.) produced increases in striatal D1 receptors and mRNA levels after treatments of 7, 14 and 21 days + 3 days withdrawal.


Developmental and age-related changes in the D2 dopamine receptor mRNA subtypes in rat brain. The influence of ontogeny and aging on the D2 dopamine receptor mRNA in rat brain were examined using in situ hybridization histochemistry and Northern analysis utilizing oligonucleotide probes complementary to the different D2 mRNA subtypes. At birth, there was a high level of D2 dopamine receptor mRNA in corpus striatum relative to that found in the cerebral cortex and other brain areas. The hybridization signal of striatum (using a probe that hybridizes to both the D2A and D2B mRNA) increased during the first two postnatal weeks, reached a peak at day 16, then declined slightly. The D2A mRNA showed a similar distribution and developmental pattern. Intracisternal injection of 6-hydroxydopamine into neonates did not significantly alter the increase of the D2 dopamine receptor mRNAs, suggesting that neuronal input does not influence the ontogenetic development of this mRNA. In striatum, olfactory tubercule and inferior colliculus, the D2A mRNA declined between 3 and 24 months of age. By contrast, there was an age-related increase in the D2A mRNA in the anterior and intermediate lobes of the pituitary. The mRNA for the D2B dopamine receptor showed very low but nevertheless detectable levels in striatum, olfactory tubercule and pituitary. Like with the D2A mRNA, in 24-month-old rats the D2B mRNA declined in striatum and olfactory tubercule and increased in pituitary. These results show that there are differential tissue-related changes in the mRNAs for the D2 dopamine receptor during both development and aging.


Presynaptic dopamine autoreceptors and second messengers controlling tyrosine hydroxylase activity in rat brain. In brain areas enriched of dopaminergic nerve terminals presynaptic dopamine (DA) autoreceptors control the state of activation of tyrosine hydroxylase (TH) by regulating the extent of phosphorylation of the enzyme. Evidence is presented indicating that this autoinhibitory control may involve a decrease in the cyclic AMP-dependent activation of TH through an inhibitory coupling of presynaptic DA autoreceptors to adenylate cyclase. As indicated by the insensitivity of the DA inhibition of TH to changes in the extracellular concentrations of Ca++, to the addition of the Ca++ ionophore A 23187 and of different K+ channel blockers, a reduction of Ca++ influx and an increase in the K+ channel activity do not seem to be involved in the presynaptic regulation of TH activity by DA autoreceptors at least under basal conditions.


Location and molecular cloning of D1 dopamine receptor. Recently, our laboratory has purified the D1 dopamine receptor 6600 fold to near homogeneity from digitonin solubilized rat striatal membranes using sequential affinity, ion exchange, lectin, and size exclusion chromatographies. The resulting receptor preparations still retained ligand binding activity (-11,000 pmol [3H]SCH 23390 bound per mg/protein) and appeared as a single band at 70-80 kDa on SDS-PAGE. In order to learn more about the sequence and structure of this protein, we recently cloned the gene for a human CNS D1 dopamine receptor. This gene has an open reading frame of 1388 nucleotides and encoded for a protein with a deduced amino acid sequence of 446 residues. When expressed in mammalian cells the cloned D1 receptor had all the ligand binding properties expected for a D1 receptor (SCH 23390 > cis flupenthixol > raclopride and SKF 38393 > apomorphine > dopamine > quinpirole). The cloned D1 receptor was found to stimulate adenylyl cyclase but not phospholipase C. The message for this D1 dopamine receptor was found in caudate, putamen, frontal cortex, and hippocampus, but not in substantia nigra, heart, or kidney. These accomplishments now will allow the pursuit of biochemical studies of the receptor protein as well as investigations into structure/function relationship of the receptor using a molecular biological techniques.


The Na(+)-Ca++ exchanger in central nerve endings: the relationship between its pharmacological blockade and dopamine release from tuberoinfundibular hypothalamic neurons. 2', 4'-Dimethylbenzamiloride (DMB), an inhibitor of Na(+)-Ca++ antiporter dose-dependently (10-100 microM) inhibited Na(+)-dependent 45Ca++ efflux from brain synaptosomes. This compound was also able to stimulate basal release of [3H]DA from superfused TIDA neurons. Another amiloride analogue, 5-N-methyl-N-guanidinocarbonylmethylamiloride (MGCMA, 100-300 microM), which lacks of inhibitory properties on the Na(+)-Ca++ antiporter, failed to modify basal [3H]DA release from TIDA neurons. In addition, when the antiporter operates as a Ca(++)-influx pathway, DMB dose-dependently inhibited Na(+)-dependent 45Ca++ uptake in brain synaptosomes, whereas it did not prevent K(+)-induced 45Ca++ uptake, which reflets the activation of voltage-operated Ca++ channels. Finally DMB inhibited ouabain-induced [3H]DA release, which depends on the activation of the Na(+)-Ca++ exchanger due to the inhibition of the Na+/K(+)-ATPase pump.


A novel in vitro method for investigating cartilage degradation. A novel in vitro microassay is described which allows the direct effects of short-lived cells or transient cell processes on cartilage matrix to be investigated. The method involves layering cells onto 2 microns cryostat sections of cartilage and assessing matrix integrity with quantitative histochemistry. Rat polymorphonuclear neutrophils (PMNs) caused glycosaminoglycan (GAG) loss from sections of bovine nasal cartilage. This loss of GAG was greatly enhanced by the presence of zymosan, phorbol ester or calcium ionophore. Similar results were obtained using human articular cartilage with human PMNs. This technique may be useful in the detection of novel chondroprotective agents.


Drug effects on a novel in vitro model of cartilage breakdown. A new in vitro model for studying cartilage breakdown has been utilised in this work. Polymorphonuclear neutrophils (PMNs) with phorbol myristate acetate (PMA) were layered onto 2 microns cryostat sections of bovine nasal cartilage. After incubation, the sections were fixed, stained, and the amount of glycosaminoglycan (GAG) contents measured by microdensitometry. PMNs caused GAG loss from sections and this was greatly enhanced when the PMNs were activated by PMA. Various pharmacological agents were then added to the system, namely acetyl salicylic acid, indomethacin, ibuprofen, piroxicam, dexamethasone, D-penicillamine, chloroquine and BN50548. The drugs tested had no direct effect on cartilage matrix, nor did they affect GAG loss from sections treated with non-stimulated PMNs. However, BN50548, a novel protease inhibitor, afforded a dose response protection of cartilage section from GAG loss by PMA stimulated PMNs. This model may prove to be of value in screening novel antiproteases with chondroprotective activity.


A comparative study of nabumetone and indomethacin in ankylosing spondylitis. Forty-two patients with ankylosing spondylitis were entered into a double-blind study to compare treatment with indomethacin and a new non-steroidal anti-inflammatory drug, nabumetone. Clinical, laboratory and side-effect profiles were measured over a three month period. Both drugs were effective in relieving pain and morning stiffness, indomethacin was better in alleviating general stiffness, nabumetone resulted in less side-effects. Objective measurements of spinal movements revealed no difference between the two drugs. Nabumetone, available as Relifex, appears as effective as indomethacin in relieving the symptoms of ankylosing spondylitis and is possibly better tolerated.


The role of kinin system in joint inflammatory disease. Components of the kallikrein-kininogen-kinin are activated in response to noxious stimuli (chemical, physical or bacterial), which may lead to excessive release of kinins in the synovial joints that may produce inflammatory joint disease. The inflammatory changes observed in synovial tissue may be due to activation of B2 receptors. Kinins also stimulate the synthesis of other pro-inflammatory agents (PGs, LTs, histamine, EDRF, PGI2 and PAF) in the inflamed joint. B2 receptor antagonists may provide valuable agents as new analgesic drugs. Further, it is suggested that substances directed to reduce the activation of KKS may provide a pharmacological basis for the synthesis of novel anti-rheumatic or anti-inflammatory drugs.


A double blind, placebo controlled study of niflumic acid gel in the treatment of acute tendinitis. Percutaneously administered niflumic acid gel (Niflugel R, Laboratories UPSA, Rueil Malmaison, France) was compared to placebo in a double blind, placebo controlled, multicentre study in the treatment of acute upper and lower limb tendinitis. Fifty nine subjects were enrolled in three centres and were randomly allocated to receive treatment with 2.5% percutaneous niflumic acid gel or placebo gel applied three times daily for 7 days. Clinical evaluations were carried out on inclusion and after seven days of treatment. The variables measured were pain felt by the patient and the investigators' and patients' overall evaluation of the treatments' efficacy. The patients also kept a daily record of pain scores. Any adverse events that occurred were noted. The results showed that niflumic acid gel was significantly better than placebo in improving patient signs as regards overall efficacy ratings. Global evaluation of efficacy rated by the investigator showed that 25/29 patients (86.2%) were healed or improved in the niflumic acid gel group compared with 11/27 patients (40.7%) on placebo, p = < 0.01. The overall assessment of tolerance showed no difference between groups. Only two minor adverse effects were reported in patients treated with niflumic acid gel, and they did not require patients to stop treatment. The study findings indicate that treatment with topical niflumic acid gel is effective in the treatment of tendinitis and results in improved clinical signs at the end of 7 days.


A clinical comparison of two leading non-steroidal anti-inflammatory drugs. One hundred patients with rheumatoid arthritis were entered into a randomised, double-blind, cross-over study of naproxen (500 mg b.d.) and diclofenac (50 mg t.i.d.). Each treatment period lasted four weeks with a wash-out period of up to one week on admission and again between periods of active therapy. Compared with baseline, both treatments significantly reduced the duration of morning stiffness, Ritchie Articular Index, daytime and night-time pain and produced a significant improvement in the disease status. Forty-two non-serious presumed side-effects were reported in 21 patients (21%). All were characterised by common everyday signs and symptoms. These largely related to the upper gastrointestinal tract and typical of those commonly reported for non-steroidal anti-inflammatory agents. There were no statistically significant differences between the two treatments for any of the efficacy parameters or in the incidence of side-effects. Patients also expressed an equal preference for the two drugs.


Variations between rheumatologists in using sulphasalazine. The increased use of audit and resource management within the health service will focus attention on variations in clinical practice. We have looked at one rheumatological example; the extent rheumatologists vary in their clinical use of a slow-acting anti-inflammatory drug. We studied a single drug - sulphasalazine. In a prospective study sulphasalazine was given to 298 rheumatoid patients at 24 rheumatology centres in South East England. They were followed for 6 months. There were large differences between centres in: the types of patient started on therapy; the numbers of patients remaining on treatment; the responses after 6 months. The difference between some centres was more marked than the expected improvement in clinical and laboratory variables given by sulphasalazine. The use of a slow acting anti-rheumatic drug like sulphasalazine in rheumatoid arthritis is agreed by most rheumatologists in the UK and yet there are wide variations in its use. Our results question the validity of comparing clinical practice and associated costs between centres for even a simple clinical procedure.


Four commonly prescribed non-steroidal anti-inflammatory drugs for rheumatoid arthritis. A four-way single-blind crossover study was used to compare the efficacy and tolerance of four non-steroidal anti-inflammatory drugs. In addition, pain intensity was compared during the day, at night, at rest, on walking, in the most painful joint, and with the patients most painful activity. Ninety-six patients with rheumatoid arthritis took single daily doses of controlled release naproxen (N), diclofenac S.R. (D), indomethacin S.R. (I) and standard piroxicam (P). The greatest changes from baseline after treatment were seen in those patients with the highest initial pain measurement scores. Assessments of pain in the morning, in the most painful joint and the most painful activity were more discriminating than those at noon or at rest. Of the treatments, 'N' and 'P' were the most effective in reducing pain, with statistically significant differences from baseline. 'I' was the most effective in reducing morning stiffness. Adverse experiences were generally mild, occurring more frequently on 'I' than on other treatments.


The epidemiology of NSAID associated gastrointestinal disease. Many problems make it difficult to estimate the exact risk of peptic ulceration and its complications, perforation and bleeding, in patients receiving NSAIDs. Nevertheless the association of these events and treatment is now beyond dispute. Deaths are a particular problem in the elderly since mortality from peptic ulcer disease rises steeply after age 60. Risk factors identified with hospitalisation for gastrointestinal problems in patients receiving NSAIDs include age, previous gastrointestinal symptoms, corticosteroid use and disability. The risk of death is highest in elderly females and is substantial.


The science--equivalent efficacy and diminished risk. Nabumetone is an effective anti-inflammatory drug in models of inflammation and in man, comparable in potency to other compounds of this type. It differs from other compounds in several important respects. The parent molecule is non-acidic and virtually inactive but is transformed to an active metabolite (6MNA) by the liver. 6MNA is not excreted in bile and cannot therefore, by reflux from the small intestine, reach the stomach. Many other compounds can reach the stomach in this way even when given by routes other than oral, for example by suppository. Prostaglandin production by the stomach, a protective mechanism, is not markedly affected by 6MNA whereas it is suppressed by other NSAIDs. These studies suggest a favourable therapeutic ratio for nabumetone.


Concerns and choices in general practice. Osteoarthritis is a common problem in general practice and a major indication for NSAIDs. Many patients with osteoarthritis are elderly and therefore particularly at risk from adverse reactions. Co-morbidity and co-prescription may lead to drug interactions. For these reasons, safe NSAIDs are the first choice for this disease.


Gastroscopic evaluation of the effects of nabumetone on the gastrointestinal mucosa of rheumatic patients. Endoscopic studies with nabumetone have consistently shown a lower incidence of gastro-duodenal erosive lesions than comparable non-steroidal anti-inflammatory drugs (NSAIDs) including naproxen and ibuprofen.


Efficacy and improved safety--a new anti-arthritic agent. Long term studies with nabumetone have confirmed that it is an effective NSAID, comparable to other agents including aspirin and naproxen. Large scale post-marketing studies have shown high response rates and good tolerance.


The long-term U.S. study--a report on outcome and tolerance. Altogether 1,912 patients have been enrolled in studies of nabumetone in the United States. They were all patients with osteoarthritis or rheumatoid arthritis. After completing participation within randomised studies patients were entered into an open study which continued for up to five years. These cases provide longterm efficacy and safety data for the use of nabumetone. About 25% of patients were withdrawn because of lack of efficacy; most of these withdrawals were in the first year of therapy. There was a similar picture with side-effects. About 12% of patients were withdrawn, mostly in the first year. Many patients continued to take nabumetone for five years without adverse effects and with continuing efficacy. The numbers of patients in whom nabumetone was stopped due to lack of efficacy or an adverse reaction was similar in those aged over 65 years and in patients aged less than 65 years. These results show that nabumetone is a safe and effective anti-inflammatory drug in long term clinical use.


A rheumatologist's viewpoint.

A rheumatologist's viewpoint. Attitudes to prescribing anti-inflammatory drugs have changed considerably over the last 25 years and there is now a recognition of the need to balance effectiveness with reduced risks of serious adverse reactions. Such serious side-effects often involve the upper gastrointestinal tract, and there are differences between anti-inflammatory drugs in the frequency with which they cause significant problems at this site. Anti-inflammatory drugs with a lesser propensity to cause gastrointestinal reactions may have an advantage. Several risk factors may be important for upper gastrointestinal side-effects including sex, age, history of dyspepsia, other diseases and the type of arthritis. Results from post-marketing surveillance studies of nabumetone in the United Kingdom and the Federal Republic of Germany showed that although patients with a previous history of dyspepsia were more likely to stop the drug due to an adverse reaction, the majority continued without any problem. Interestingly, patients with rheumatoid arthritis were more likely to stop therapy due to side-effects, though it was not clear if this was due to their disease or to multi-morbidity. Strategies are needed when prescribing anti-inflammatory drugs which take into account the type of patient, their disease, and the best drug. In many instances this could be nabumetone.


Pharmacokinetic profile of droxicam.

Pharmacokinetic profile of droxicam. Droxicam is a new non-steroid anti-inflammatory drug that is a pro-drug of piroxicam. The pharmacokinetics of droxicam, both as a single 10mg dose and as a multidose regimen of 10 and 20mg/day for 20 consecutive days, have been studied in healthy volunteers. Since transformation into piroxicam takes place in the gastrointestinal tract, unchanged droxicam was not detected in plasma. After a single 10mg dose the value of Tmax was higher than that reported for piroxicam (10mg). This effect is a consequence of the process of transformation of droxicam into piroxicam. The remaining pharmacokinetical parameters studied were similar to those reported in other studies on piroxicam (10mg). After multiple oral administration at a dose of 10 and 20mg/day, absorption kinetics of droxicam were delayed with respect to those of piroxicam. The other pharmacokinetical parameters studied showed no statistically significant differences between droxicam and piroxicam. Absorption and elimination of droxicam are independent of the administered dose and the bioavailability of droxicam and piroxicam was equal. The influence of gastric emptying on droxicam pharmacokinetics and bioavailability has been investigated in healthy volunteers. Gastric emptying was experimentally modified by use of propantheline and metoclopramide. Following modification of gastric emptying, only Tmax underwent significant increase (P < 0.05). Absorption rate of droxicam was modified but elimination and bioavailability did not suffer modification in conditions of altered gastric emptying.


A double-blind randomised controlled trial of droxicam versus indomethacin in rheumatoid arthritis. This double-blind randomized controlled trial compares the efficacy of droxicam (20mg/day) and that of indomethacin (100mg/day) administered to 20 patients (7 men, 13 women; aged 54.7 +/- 13.2 years) with active classical or definite rheumatoid arthritis during 9 weeks, after a 7-day single-blind run-in paracetamol (1,500mg/day) period. Evaluations were carried out at weeks 0 (washout), 1,2,4,6 and 9. After 9 weeks of treatment, both drugs showed a statistically significant improvement of joint pain intensity, articular index (number of swollen or painful joints and degree of involvement), duration of morning stiffness, functional capacity, and level of fatigue. Inter-treatment differences at all study intervals were not observed. Grip strength improved only in indomethacin-treated patients. Withdrawals due to lack of therapeutic efficacy did not occur. Side effects occurred in four patients from each group. One patient in the indomethacin group withdrew at the week 1 due to epigastric pain and heartburn. In conclusion, droxicam (20mg/day) seems to be as effective as indomethacin (100mg/day) in the alleviation of symptoms in patients with rheumatoid arthritis.


Therapeutic activity, clinical and gastric tolerance of 20mg daily dose of droxicam in comparison with piroxicam in patients with degenerative joint disease. The efficacy and safety of droxicam were compared with piroxicam in a pilot study in twenty patients with degenerative joint disease. After a one week washout period a baseline gastroscopy was carried out. Treatment during the following 4 weeks was randomised to droxicam or piroxicam. Safety and tolerance parameters were monitored at weekly intervals. Pain was evaluated with two visual analogue scales (VAS) (patient and investigator). Affected joints, articular index (AI), patient's status and a daily living activities questionnaire were also evaluated. Another gastroscopy was carried out at the end of the treatment period. Droxicam and piroxicam relieved all symptoms significantly without statistically significant clinical differences. Both groups showed no drug related side effects in the laboratory values. In the gastroscopic examinations two patients of the droxicam group and four of piroxicam group had minor gastric erosions after four weeks of treatment without any accompanying clinical symptoms.


Double-blind, randomized and parallel comparison between droxicam and diclofenac sodium in patients with coxarthrosis and gonarthrosis. This double-blind clinical trial compares droxicam, a new non-steroidal anti-inflammatory agent and the reference compound diclofenac sodium. After a 7 day placebo run-in period, 80 patients with gonarthrosis and coxarthrosis were randomized to receive 20mg/day of droxicam and 150mg/day of diclofenac for 6 weeks. Evaluations were carried out at weeks 0 (placebo run-in), 2,3, and 6. Both drugs showed statistically significant improvements in all clinical measurements (index of severity, pain intensity, morning stiffness, maximal forced flexion and extension of the knee) after 6 weeks of treatment. Investigator's and patient's opinions were consistent with these results. The consumption of paracetamol was significantly lower amongst patients treated with droxicam. Withdrawals due to lack of therapeutic efficacy did not occur. A lower incidence of side effects, mostly upper gastrointestinal symptoms, was noticed amongst droxicam-treated patients. However, two patients in the droxicam group were withdrawn at week 3 and two days after week 6 because of epigastric pain and nausea, and cutaneous rash, respectively. Both study drugs are of benefit in reducing pain and improving joint motion and function in patients with coxarthrosis and gonarthrosis.


Droxicam: a pharmacological and clinical review of a new NSAID. Droxicam acts by inhibition of PGE2 varies. Although it belongs to the oxicam family, it is characterised by being a pro-drug of piroxicam, the molecule undergoing conversion by hydrolysis once dissolved in the digestive tract. This allows us to suppose in principle that, there being less contact between the active drug (piroxicam) and the gastric mucosa, the side effects in the said mucosa would be slight. The studies which have already been performed in healthy volunteers and in patients with osteoarthritis and rheumatoid arthritis, to evaluate the efficacy and the tolerance of droxicam in patients suffering from such clearly inflammatory processes demonstrate an analgesic potential and anti-inflammatory effects which become noticeable after two weeks of treatment, and the drug is well-tolerated.


Comparative double-blind study of droxicam (new NSAID) versus indomethacin in rheumatoid arthritis. This randomized, controlled and double-blind clinical trial compares the efficacy of droxicam (20mg/day) with that of indomethacin (75mg/day) in 40 RA patients (11 male, 29 female) aged (+/- SD) 53 +/- 12.5 years. After a 7-day single-blind run-in placebo period, patients were divided into two groups and treated for 9 weeks. Assessments were done at baseline and at the end of the 1st, 2nd, 4th, 6th and 9th weeks. Both drugs improved significantly the articular pain, the duration of morning stiffness, the articular index, the functional status and the degree of fatigue. Patient's and doctor's opinions were in accordance with the above-mentioned results. The effect of both drugs was more noticeable in the first 2 weeks of treatment. Droxicam was found to be statistically more active than indomethacin in alleviating morning stiffness and improving the functional status. The improvement of the variables induced by droxicam increased progressively throughout the study whereas that induced by indomethacin remained unchanged after the 2nd or 4th week of treatment. One patient treated with indomethacin withdrew from the study due to staggering and dizziness and several patients reported dyspepsia. Droxicam seems to be as effective as indomethacin (75mg/day) in the symptomatic relief of RA patients. The possibility of the use of droxicam for the relief of morning stiffness is of particular interest.


A pharmacokinetic study to evaluate the profile of droxicam in elderly healthy volunteers after a single oral dose of 20mg. A single oral dose pharmacokinetic study in a group of 10 elderly healthy volunteers was performed to evaluate the pharmacokinetic profile and the potential effect of age on the absorption, distribution and elimination of droxicam. After complete medical screening, and informed written consent, one dose (20mg) of droxicam was administered to all volunteers, under medical supervision. A complete pharmacokinetic profile of the obtained blood plasma levels was evaluated over 120 hours. All volunteers completed the study and in none did droxicam cause intolerance or side effects. The results showed that droxicam absorption, distribution and elimination did not differ substantially from reference studies done with young healthy volunteers. The peak mean plasma concentration was at 10 hours 1.38 +/- 0.29 microgram/ml, declining slowly, reaching 0.24 +/- 0.20 microgram/ml at 120 hours, with a half life of 50.23 +/- 17.19 hours and an elimination rate constant of 0.015 +/- 0.005 microgram/ml.h-1. In comparison to the healthy, young volunteers, the variation was minimal. It can be concluded from this study that age causes minimal variations in the absorption and distribution of droxicam.


Adverse events with droxicam in the early clinical trials. This study analyses the results of 8 randomized, controlled clinical trials and one open study carried out with droxicam (a new NSAID, pro-drug of piroxicam), comparing the adverse events and gastrointestinal tolerance of this compound against those of the control drugs used in these trials. The frequency of adverse events was lower in the droxicam treated patients. Adverse events concerning the gastrointestinal area were also lower. No differences were found in the distribution of adverse events by age of sex among the drugs compared. The pattern of side effects found was that expected in all non-steroidal anti-inflammatory agents. These results seem to sustain the hypothesis of a better tolerance of droxicam than that of piroxicam, indomethacin or diclofenac, especially in the gastrointestinal area.


[Angiocardiography in the diagnosis of interventricular septum defects in a double displacement of great vessels from the right ventricle]. The paper is devoted to analysis of the results of angiocardiographic investigation of 237 patients with a double deflection of great vessels (DDGV) from the right ventricle (RV) (the patients ranged in age from 3 months to 23.5 years) to study the potentialities of the method in the diagnosis of a defect position of the interventricular septum (DIVS). Angiographic investigation permitted a sufficiently accurate determination of a DIVS position in DDGV from the RV. Of paramount importance for determining a DIVS position is the establishment of the interrelationships of the latter with the infundibular septum and the openings of major arteries. For diagnosis of a DIVS position one should necessarily use left and right ventriculography both in standard and axial projections.


[Axillary approach for radiologic endovascular dilatation]. Basing on the analysis of 39 observed cases, the authors consider various aspects of the use of roentgenovascular dilatation by an axillary access : problems of methods, indications and contraindications; they also assess the advantages and shortcomings of the access.


[Effect of contrast ventriculography of the left ventricle on coronary hemodynamics in patients with ischemic heart disease]. The effect of left ventricular (LV) contrast ventriculography (VG) on the state of intracardiac hemodynamics during the administration of a contrast medium and 30-40 sec. after it was investigated in 48 CHD patients. It followed retrograde catheterization of the left ventricle by a parallel use of two catheters that permitted recording intraventricular pressure directly during LV VG. The performance of left VG with 76% urografin administered in a dose of 0.6-0.8 ml/kg with the rate of 13-15 ml/s produced no significant change in the state of intracardiac hemodynamics, relaxation and pumping function of the LV in the course of the first three contrasted cardiocycles. Transitory disorder of hemodynamics observed in the patients after contrast VG was restored by itself in 15-20 min.


[Diagnosis of coronary artery restenosis after radiologic endovascular dilatation]. Altogether 40 patients with stable angina of effort were investigated in a long-term period after roentgenovascular dilatation of one or two coronary arteries. Control coronarography was performed in 22 patients with lowered exercise tolerance. A reliable feature in the development of hemodynamically significant restenosis and/or "new" coronary stenosis in 11 patients was a combination of average and low exercise tolerance with its negative dynamics. For patients with I functional class, a sign of restenosis and/or "new" stenosis was the appearance of the ischemic shift of the CT-segment on ECG during bicycle testing. An efficient selection of patients resulted in increased sensitivity and specificity of noninvasive tests.


[Radiodiagnosis of a small amount of fluid in the pericardial cavity]. X-ray symptomatology of small pericardial effusions was studied on the basis of analysis of clinicoroentgenological and echocardiographic investigation of 173 patients with various chest diseases. Comparison of x-ray and USI results led to a conclusion of the effectiveness of polypositional roentgenography for the detection of small amounts of fluid in the pericardial cavity.


[Tolerance to various radiologic contrast agents used for coronary angiography in patients with acute myocardial infarction]. Coronary angiography (CAG) was performed in the acute period of myocardial infarction in 41 patients using verografin and in 38 patients using omnipack. In a high risk of CAG performance the tolerance of omnipack was better than that of verografin. Omnipack causes allergic reactions less frequently, disturbs less azote excretory function of the kidneys and myocardial bioelectric activity.


[Screen-grid mammography].

[Screen-grid mammography]. A device and the results of a 3-year performance of cellular grids for mammography were described. An increase in the informative value and a decrease in radiation exposure of patients were shown during mammography with a cellular grid.


Necrotising fasciitis: an entity revisited. Necrotising fasciitis is a disease that still carries a high morbidity and mortality despite our better understanding and advances in treatment since 1924 when Meleney first studied it. In our Department of Orthopaedics, this condition appears to be on the increase, and we therefore felt this entity deserved a restudy. Since 1985, 15 cases were seen, of which 10 were encountered in 1989. There were no recorded case prior to 1985. Our initial results show that the background and outcome parallel that of previous authors. Most were elderly with some form of underlying chronic disease. The duration from symptom onset to presentation was short, with many being in a state of septicaemia at the time of admission with fever, metabolic acidosis and marked leucocytosis. Repeated desloughings were common, and four ended up with some form of limb amputation. As with Meleney's study, the consistent pathogen cultured was B-haemolytic streptococcus. Our recommendation is that we should be more aware of this entity in view of its fulminant course, with early and aggressive surgical intervention being the keystone to management.


[Fulminant erysipelas].

[Fulminant erysipelas]. An apparent resurgence of invasive and life-threatening group A streptococcal infections in young and previously healthy hosts is reported in several countries. We report a case of fatal necrotizing fasciitis and review the spectrum of these clinical syndromes, including the invasive soft tissue infections. This changing pattern of infection could be explained by an increased incidence of some serotypes of group A Streptococcus carrying specific virulence factors, such as pyrogenic exotoxins.


Application of crystallography to the design of antiviral agents. A historical review of x-ray crystallography introduces basic concepts and describes the potential of this science to the rational design of antiviral agents. Following a brief introduction to the study of antiviral compounds that inhibit early stages of rhino- and enteroviral infections, the impact of structural studies on rational drug design is discussed in relation to known viral structures.


Lessons from Leishmania: a model for investigations of CD4+ subset differentiation. Infection of inbred mice with Leishmania major remains the best model of human infection with visceralizing Leishmania that cause kala-azar. Immunologic investigations have correlated the outcome of disease with expansion of different subsets of CD4+ cells, designated Th1 and Th2. Although the capacity of fixed effector Th1 and Th2 populations to mediate the diverse outcomes of disease through the release of soluble cytokines, particularly IFN-gamma and IL-4, has been demonstrated, the mechanisms by which these subsets become established during infection have not been delineated. This review focuses on known features of CD4+ differentiation using other experimental models, and proposes that genetic susceptibility to Leishmania can occur if the host has a Th2 precursor cell in the memory configuration prior to the time of exposure to organisms, perhaps in response to cross-reactive self-peptides. The hypothesis can explain a number of puzzling observations in both murine and human disease due to these organisms and makes several predictions amenable to experimental testing.


Biological and social determinants of the Lyme disease problem. Lyme disease, presently the most common arthropod-borne disease in the United States, is a phenomenon of both medical and social importance. Notwithstanding the substantial public health threat posed by Borrelia burgdorferi infection, there is reason to suspect that the diagnosis of Lyme disease is made more frequently than justified. On the other hand, the current dissatisfaction with serologic assays for B. burgdorferi infection may lead some physicians to inappropriately abandon consideration of the diagnosis entirely. Either of these outcomes of the patient-physician encounter is to be regretted. The Lyme disease problem, as I call the current situation, has both biological and social determinants.


Trends and controversies in the prophylaxis and treatment of malaria. Several areas of clinical concern and investigation have emerged over the past year in the malaria field. Mefloquine prophylaxis has required a change in its dosing regimen. Continued monitoring for potential mefloquine toxicity has shown this agent to be safe for use for many populations, but not routinely for pregnant women or for young children. Chloroquine-resistant Plasmodium vixax may be geographically limited currently, but its presence in Irian Jaya has serious implications, should be problem spread. The currently available fluoroquinolone antibiotics possess antimalarial activity but they have not proven to be clinically dependable for the treatment of resistant Plasmodium falciparum infections. However, continued investigation of both their mechanisms of action and efficacy should not be abandoned. Adjunctive measures for the control of mosquito vectors and the prevention of human contact with mosquitoes assume greater importance as both pharmacological prophylaxis and therapy for malaria infections become increasingly difficult. Health professionals who advise travelers to endemic regions should emphasize the use of safe topical repellents and residual insecticides, which can be impregnated into bed netting and clothing.


Traveler's diarrhea: new perspectives.

Traveler's diarrhea: new perspectives. Despite pre-travel advice about food and water, traveler's diarrhea is the most common infectious disease problem for travelers to developing countries. New concepts of antimicrobial prophylaxis, combination treatment with antimicrobial and antimotility agents and even a new potential vaccine are reviewed.


Complement receptors, adhesion, and phagocytosis. Phagocytosis is an essential component of host defense against invading pathogens. Although many cell types can ingest particulate material, "professional phagocytes" perform this function much more efficiently than other cells because they express unique membrane proteins and signal transduction mechanisms. This review addresses the current state of knowledge about the process of phagocytosis and its regulation.


Astroviruses and caliciviruses: emerging enteric pathogens. Acute, infectious gastroenteritis is an extremely common disease that contributes significantly to morbidity and mortality worldwide. In the United States, it is the second most frequent illness encountered in families. While this illness generally runs a self-limited course, it may be temporarily incapacitating and impact substantially on numbers of days lost from work or school. At present, 30-40% of infectious gastroenteritis cases in the United States are attributable to viral agents, while 20-30% are due to bacteria and parasites. These estimates are almost certainly low, since the cause of gastroenteritis is not discernible in approximately 40% of the cases, and gastroenteritis may be caused by viruses or other pathogens that cannot be identified at this time. Rotavirus and enteric adenovirus are two of the most prevalent and well-studied of the viral agents and have been reviewed extensively elsewhere. This review focuses on two broad groups of small round structured viruses (SRSV), astroviruses and caliciviruses (classic, Norwalk, and Norwalk-like). Although recognized in association with acute, nonbacterial gastroenteritis since the early 1970s, the study of these viruses has been hampered by the relatively low levels of viral shedding in feces, difficulty in propagating the virus in cell or organ culture, and the lack of widely available, well-standardized reagents for their detection. In spite of these obstacles, much has been learned about these viruses using standard virologic (electron microscopy, biophysical characterization, immunoassays) and epidemiologic methods. More recently, substantial progress has been made in studying astroviruses and caliciviruses at the molecular level. Molecular techniques are now being used as diagnostic aids to characterize the epidemiology of these agents in greater detail.


Needle exchange or needless exchange? The state of the debate. Needle exchange programs have been implemented in many cities around the world to slow the spread of human immunodeficiency virus (HIV) infection among injecting drug users. Whether these programs are succeeding in reducing HIV incidence is a matter of debate, as is the appropriateness of sanctioning the provision of drug injection equipment in the midst of a "war on drugs." In a debate swollen with emotional arguments on both sides of the issue, scientific research is essential, lest discussion of needle exchange becomes needless exchange at the policy level. This article briefly outlines and critiques the common arguments for and against needle exchange. Following this, a new circulation theory of needle exchange is advanced, along with supporting evidence from an ongoing study in New Haven, CT, U.S.A. Finally, several open questions relating to the operation of needle exchange programs and the behavior of program clients are suggested for further investigation.


Respiratory syncytial virus and ribavirin: quo vadis? Respiratory syncytial virus is the major respiratory pathogen in infants and young children. Every year, this unique and ubiquitous virus accounts for substantial morbidity and occasional mortality in this age group. Until recently, therapy for respiratory syncytial virus infections was limited to supportive measures such as hydration, supplemental oxygen, and assisted ventilation. Therefore, the licensure of ribavirin in 1986 for treatment of respiratory syncytial virus infections raised hopes for specific and effective therapy. However, the use of ribavirin has been the subject of continuing controversy and debate. Despite at least eight controlled clinical trials involving collectively over 170 patients treated with ribavirin since 1983, no clear consensus has developed regarding which patients should be treated with ribavirin. Major issues are weaknesses in the design and methodology of studies that claim treatment efficacy, the clinical significance of the demonstrated treatment effects, potential teratogenicity to health care workers exposed to aerosolized ribavirin, and cost-effectiveness of the intervention. This review will explore each of these areas of controversy and consider the unanswered questions to which future research must be directed.


Entry of Trypanosoma cruzi into eukaryotic cells. Trypanosoma cruzi invades a variety of mammalian cells by receptor-ligand interactions. In this review two T. cruzi carbohydrate-binding proteins, neuraminidase/trans-sialidase and penetrin, are discussed as possibly playing a role in parasite entry into mammalian cells.


Cytomegalovirus vaccines: current status. Clinical observations on the natural history of cytomegalovirus (CMV) infections in solid organ transplant recipients and in pregnant women and their offspring provide the rationale for the development of a CMV vaccine. The Towne live vaccine has been shown to be safe and immunogenic in healthy adults. In a double-blind, placebo-controlled trial in renal transplant recipients, administration of Towne vaccine was associated with significant reduction in the incidence of severe CMV disease. The use of the Towne vaccine for prevention of symptomatic congenital infection deserves further consideration. As an alternative to live vaccine, recombinant vectors containing CMV proteins are being developed.


Pathogenesis of human herpesvirus 6 (HHV-6). The newly isolated virus, human herpesvirus 6 (HHV-6), causes exanthem subitum (or roseola infantum) as the primary infection. Liver dysfunction and neurological disorders are observed during exanthem subitum. Seroepidemiological studies have shown that almost all children are infected with HHV-6 about 6-24 months after birth. This virus also causes other diseases including lymphadenitis and infectious mononucleosis-like disease. HHV-6 has cellular tropism for CD4+ lymphocytes, in which it replicates in vivo. Its transmission is probably airborne early in life, mainly from mother to child, because it is often secreted in the saliva of healthy adults having antibody to HHV-6. Latent infection follows the primary infection and the virus can often be reactivated under conditions of immunosuppression such as AIDS or organ transplantations. The site of its latent infection is not yet known, but could be monocytes/macrophages.


Adjunctive therapy in bacterial meningitis--what make sense? Bacterial meningitis continues to cause morbidity and mortality despite bactericidal antibiotic therapy. Experimental studies of pathophysiology reveal the bacteria and their surface components within cerebrospinal fluid (CSF) induce the release of inflammatory cytokines that promote CSF inflammation, injure the cerebral microvasculature and cause brain edema. Adjunctive corticosteroids reduce inflammation, ameliorate the pathophysiology, and improve neurologic outcome in children. Practical recommendations are made for children and selected adults regarding current and future directions of adjunctive therapy.


Epstein-Barr virus infection in nasopharyngeal carcinoma. Nasopharyngeal carcinoma develops with extremely high incidence in discrete populations and geographic locations. It is consistently associated with the ubiquitous Epstein-Barr herpesvirus (EBV). The structure of EBV DNA indicates that the tumor is a clonal proliferation that developed subsequent to EBV infection. Specific viral genes are consistently expressed within all cells of the tumor. This consistent expression may indicate that the viral gene products are required for tumor growth. Genetic or environmental factors may affect the expression of these critical viral genes or cellular genes and contribute to tumor progression.


Host-parasite interactions in Taenia solium cysticercosis. Human neurocysticercosis results from infestation of the central nervous system with the metacestode form (tissue cyst) of Taenia solium. Cysticercosis is being increasingly recognized as a cause of neurologic symptoms in residents and emigrants from developing countries. Taeniid parasites have developed elaborate mechanisms to persist in the tissues of their intermediate hosts. The invasive larvae, termed oncospheres, are susceptible to antibody and complement. However, by the time that the host has generated an antibody response, the parasites have begun to transform to the more resistant metacestode form. The metacestodes also have means of evading complement-mediated destruction, including paramyosin, which inhibits C1q; taeniaestatin, which inhibits both classical and alternate pathways (likely by inhibiting factor D and C3 esterase); and sulfated polysaccharides, which activate complement away from the parasite. Similarly, antibody does not seem to be able to kill the mature metacestode. The parasites may even stimulate the host to produce antibody, which could be bound via Fc receptors, and used as a source of protein. Finally, taeniaestatin and other parasite molecules may interfere with lymphocyte proliferation and macrophage function, thus paralyzing the cellular immune response. Because the symptoms of neurocysticercosis are typically associated with a brisk inflammatory response, we hypothesize that disease is primarily the result of injured or dying parasites. This hypothesis raises important questions in assessing the role of chemotherapy in the management of neurocysticercosis as well as in evaluation of clinical trials, most of which have been uncontrolled.


The role of mannose-binding proteins in host defense. The human mannose-binding protein (MBP) appears to function as an "ante-antibody" as its physiological role is in first line host defense. Low baseline serum levels are rapidly increased as part of the acute phase reactant and circulating MBP can act as a direct opsonin or activate the classical alternative complement pathway. MBP appears to selectively recognize an array of apparently disparate oligosaccharides that decorate gram-negative and gram-positive bacteria as well as certain parasites, yeasts, and fungi. MBP may be considered a "pattern" recognition molecule that has homologs in primitive life forms. Its ability to distinguish self from nonself indicates that it may play an important role in innate immunity.


The structure and function of the surface lipophosphoglycan on different developmental stages of Leishmania promastigotes. The differentiation of Leishmania promastigotes from a noninfective procyclic stage to an infective metacyclic stage during growth within the midgut of their sand fly vectors or within axenic culture is accompanied by structural modifications of the surface lipophosphoglycan (LPG). The modifications are of two sorts: (a) a two- to three fold increase in size due to an increase in the number of phosphorylated saccharide units expressed and (b) a change in the composition of the terminal sugars of some of these units. The elongation of LPG on metacyclics promotes complement activation and C3 deposition in a nonlethal manner, thus opsonizing the promastigotes for attachment and uptake via macrophage receptors appropriate for subsequent intracellular survival. The down-regulation of terminally exposed galactose residues on metacyclic LPG appears to permit the selective release of infective-stage organisms from adhesion to midgut epithelial cells so as to make them available for subsequent transmission by bite.


Plasmodial hemoglobin degradation: an ordered pathway in a specialized organelle. During its intraerythrocytic development, the malarial parasite devours most of the hemoglobin in its host cell. This enormous catabolic process is achieved through an ordered, efficient degradative pathway that takes place in a specialized organelle, the digestive vacuole. The amino acids generated are used by the parasite for its growth and maturation; the heme released is polymerized into a crystalline matrix called hemozoin. We are beginning to understand the special enzymes that participate in this pathway. We do not yet fully understand the relative importance of exogenous versus catabolically generated amino acids, the function of hemozoin, the mechanism of action of quinoline drugs that concentrate in the digestive vacuole, or the mechanism of protection from malaria of variant hemoglobin gene carriers.


Trans-splicing in protozoa and helminths. Trans-splicing is defined as the process whereby exons derived from two separately transcribed RNAs are joined together. In one type of trans-splicing, nuclear pre-mRNAs acquire their 5' terminal exon (the spliced leader) from a small spliced leader RNA (SL RNA) via an RNA processing reaction that is directly analagous to the removal of intervening sequences (cis-splicing). Such leader-addition by trans-splicing has been extensively studied in trypanosomatid protozoans and in nematodes. This review summarizes recent advances in research on trans-splicing in these two systems. Progress in elucidating functionally significant sequence elements within SL RNAs and progress in understanding the mechanism and biological role of trans-splicing is discussed.


The present status of the complement fixation test in viral serodiagnosis. The complement fixation (CF) procedure has played a significant role in the diagnosis of infectious diseases for almost a century. It has accomplished this by functioning in serodiagnosis and by antigen identification particularly in clinical virology. Although it has been replaced by newer, more sensitive and rapid techniques for serodiagnosis, the CF assay is still important as a reference standard for clinical laboratories.


Visual pecking preferences in domestic chicks. Part II. The role of experience in their maintenance or not. The role of swallowing experience on the maintenance or switching of the basic visual preferences in the pecking of young chicks has been investigated using both visually attractive and less attractive seeds. It has been shown previously that chicks switch their preferences 24 hrs. later if they cannot swallow what they visually prefer whereas debeaked birds which are able to swallow large attractive seeds maintain their preferences. However, the same experiment made with glued seeds shows that the ability to swallow was responsible for the maintenance of preferences in debeaked birds. Swallowing appears to have a rewarding effect. The possibility of swallowing the visually preferred item seems to be the proximate factor which will determine whether experience reinforces basic visual preferences or, on the contrary, modify them.


Anticardiolipin antibodies in acute rheumatic fever. Recent reports describe the association of antiphospholipid antibodies (aPL) with chorea or severe heart valve lesions in systemic lupus erythematosus, lupus-like disease, or the primary antiphospholipid antibody syndrome. We conducted a case series and a case-control investigation of patients with rheumatic fever with Sydenham chorea or other manifestations of rheumatic fever for anticardiolipin antibodies (aCL) during the acute attack and disease remission. Eighty percent of patients were positive for aCL during the rheumatic fever attack vs 40% when inactive (p = 0.035); IgG and IgM aCL increased significantly with disease activity. Individuals with or without Sydenham chorea were equally positive for aCL (76 and 83%, respectively). A significant association was found between IgM aCL and carditis: All patients with valvulitis had IgM aCL (100%) vs 37% of patients without valvular involvement (p = 0.02). aPL may play a role in the pathogenesis of some clinical manifestations of acute rheumatic fever.


[Pathologic findings in migrants from developing countries: the experience of the S. Chiara di Palermo ambulatory polyclinic]. Immigrants are frequently considered as carriers of unknown and/or exotic diseases. On the basis of data collected by a working unit of Palermo, specifically devoted to the immigrants, we may affirm that the more frequent medical problems (67.1%) were of internal origin (especially gastro-enterologic, rheumatologic and dermatologic) with an important psycho-somatic component. Infections were less common (20%) especially related to respiratory diseases. Other more dangerous infections, as Tbc and HIV related diseases, were rather infrequent (3%). As a whole, our data demonstrate that control and surveillance of migrants are necessary in order to avoid diffusion of pathologies among these (compromised) hosts. The risk of transfer of infections to residents is rather low.


Effects of ketanserin and mianserin on delayed neuronal death induced by cerebral ischemia in Mongolian gerbils. We examined whether ketanserin and mianserin, drugs with 5-HT2 receptor antagonistic effects, would have protective effects in Mongolian gerbils on delayed neuronal death induced by cerebral ischemia. When training and test sessions in the passive avoidance task were carried out 6 and 7 days after 3 min of ischemia, passive avoidance impairment was apparent. Destruction and disappearance was apparent in the hippocampal CA1 neurons at 7 days after the induced ischemia. Administration of ketanserin (5-20 mg/kg) and mianserin (5-20 mg/kg) led to better passive avoidance and prevented the delayed neuronal death induced by the ischemia. These effects of ketanserin and mianserin were not inhibited by treatment with the cholinergic blocker scopolamine (5 mg/kg). Thus, ketanserin and mianserin have a protective effect on delayed neuronal death in gerbils and the effects of these drugs are not mediated by serotonergic and cholinergic systems.


Preliminary evidence for methamphetamine-induced behavioral and ocular effects in rat offspring following exposure during early organogenesis. Gravid Sprague-Dawley CD (VAF) rats received 50 mg/kg (d,l)-methamphetamine (MA) HCl (expressed as free base, N = 15) or distilled water (N = 6) by SC injection x 2/day in a 3 ml/kg volume on embryonic (E) days 7-12. Control rats were pair-fed to MA-exposed dams on days E7-18. No control dams failed to deliver; however, of 15 MA-exposed dams 4 did not deliver (2 died and 2 had completely resorbed litters). One additional MA litter had all the offspring die shortly after birth. There was no difference between groups on offspring postnatal (P) body weight. The offspring exposed prenatally to MA had significantly lower olfactory orientation scores (P9, 11, 13) to their home cage scent. In a test of early activity (P10, 12, 14) the MA-exposed progeny were marginally less active than controls. MA-exposed offspring exhibited hyperreactivity and marginally shortened response latency on a test of acoustic startle (P27). Motor activity showed no differential response in MA treated or control offspring to MA (P63) or fluoxetine challenge (P70). However, the MA offspring were more active than controls with respect to central and side activity during the second week of testing. No group differences were found for performance in a straight swimming channel or on the number of errors committed or latency to escape in a complex (Cincinnati) water maze (P84). Prenatal exposure to MA also induced eye defects (i.e., anophthalmia, microphthalmia and folded retina) in 16.7% of the progeny. However, MA did not effect hippocampal or neostriatal monoamine levels when measured on P28.(ABSTRACT TRUNCATED AT 250 WORDS)


Decreased sensory responsiveness of noradrenergic neurons in the rat locus coeruleus following phencyclidine or dizocilpine (MK-801): role of NMDA antagonism. The effects of the schizophrenomimetic compound phencyclidine (PCP) on baseline activity and sensory-evoked responses of noradrenergic locus coeruleus neurons were studied with extracellular single-cell recording techniques in the chloral hydrate-anaesthetized male albino rat. PCP dose-dependently decreased firing rate, induced a more regular firing pattern of the neurons, and decreased neuronal responses to a peripheral sensory stimulus (electrical stimulation of the hindpaw). These effects of PCP were significantly decreased by pretreatment with reserpine or yohimbine, indicating that the effects of PCP were largely indirect and mediated through noradrenaline, i.e. by inhibition of its re-uptake, resulting in stimulation of alpha 2 autoreceptors. The effects of PCP were, however, mimicked by dizocilpine (MK-801), a selective non-competitive antagonist at excitatory amino acid receptors of the N-methyl-D-aspartate (NMDA) sub-type, suggesting a role also for NMDA receptors in the suppression of sensory responsiveness of locus coeruleus neurons by PCP. In view of the purported physiological role of the locus coeruleus, this effect of PCP may well contribute to the psychotomimetic properties of the drug.


Different capability of N-methyl-D-aspartate antagonists to elicit EEG and behavioural phencyclidine-like effects in rats. Phencyclidine (PCP), a drug inducing schizophrenia-like symptoms in humans, is reported to be a non-competitive antagonist at the N-methyl-D-aspartate (NMDA) subtype of excitatory amino acid receptors. In rats, PCP produces three dose-dependent stages of EEG patterns: 1) increase of cortical desynchronization duration; 2) increase of the amplitude of the high-frequency (20-30 Hz) low-voltage (30-50 microV) cortical background activity; 3) appearance of cortical slow (2-3 Hz) wave-sharp wave complexes. These EEG changes are accompanied by stimulatory-depressive effects such as stereotypy (circling, head weaving) and ataxia. In the present study, the EEG and behavioural effects induced by systemic administration of the NMDA antagonists dizocilpine (MK 801), dextromethorphan (DM), [(+)-alpha-(4-chlorophenyl)-4- [(phenyl)methyl-1-piperidine ethanol] (SL 82.0715), (+)3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP), cis-4-phosphonomethyl-2-piperidine-carboxylic acid (CGS 19755) have been compared to those of PCP in rats. The rank of potency for inducing PCP-like EEG stages 1-3 was as follows: MK 801 > PCP > CGS 19755 > CPP. These drugs also induced PCP-like behavioural effects. On the contrary, DM and SL 82.0715, administered up to the dose of 100 mg/kg IP, failed to induce PCP-like behavioural effects and elicited only the stage 1 of PCP-like EEG. These results strongly suggest the involvement of NMDA neurotransmission in the behavioral and EEG effects of PCP.


No psychophysiological interactions between caffeine and stress? In earlier studies, the predominantly beta-adrenergic effects of mental tasks and the alpha-adrenergic effects of caffeine on cardiovascular functions were observed to be simply additive without interaction. In the present study, annoying electrical shocks were superimposed on a mental task affording either active coping, which specifically raises beta-adrenergic activation, or passive coping, and the 40 female subjects were preselected so as to differ in subjective stress susceptibility. Caffeine as well as the type of coping and the considered personality dimension produced significant effects, but almost no interactions were obtained. The stress resistant subjects, who tended toward more extraversion, emotional stability and more masculinity, had lower anxiety scores, rated their performance higher and had a greater cardiac output than the stress non-resistant subjects, who represented a rather normal population according to the FPI personality dimensions. Caffeine increased EEG alpha and beta frequency and delta power and decreased beta power, raised blood pressure and enhanced stress reactions in respiration amplitude and pre-ejection period. Active stress coping induced greater stress reactions in heart rate (increase), left ventricular ejection time (decrease) and ear pulse arrival time (decrease) than passive coping.


Pharmacological profile of a potent, efficacious fentanyl derivative in rhesus monkeys. The recent synthesis of fentanyl derivatives, some of which appear to have novel profiles of pharmacological effects, has provided compelling evidence that mu opioid efficacy might be altered systematically by modifications in the parent compound fentanyl. In the present study a new 4-(heteroanilido)-piperidine, compound 28, was studied for its effects in rhesus monkeys. In self-administration studies compound 28 maintained rates of lever pressing similar to those maintained by alfentanil; the reinforcing effects of compound 28 were attenuated by the opioid antagonist quadazocine. In drug discrimination studies compound 28 did not substitute for the kappa agonist ethylketocyclazocine and did substitute for the mu agonist alfentanil. In morphine-treated subjects discriminating between saline and naltrexone, compound 28 did not substitute for naltrexone; however, in morphine-abstinent subjects compound 28 reversed naltrexone lever responding. Moreover, this discriminative stimulus effect in morphine-abstinent subjects was antagonized by naltrexone and by quadazocine in a manner consistent with mu receptor mediation. Compound 28 also was an effective analgesic in a warm-water, tail-withdrawal procedure and it decreased markedly respiratory function. The analgesic effects as well as the respiratory depressant effects of compound 28 were antagonized by quadazocine. Together, these results show compound 28 to be a potent, efficacious mu agonist of similar potency to alfentanil. Large differences in apparent efficacy at mu receptors between compound 28 and another compound in this series (mirfentanil), clearly demonstrate that, within this chemical family, small chemical changes can confer significant differences in pharmacologic effect.


Adrenalectomy reverses chronic injection-induced tolerance to nicotine. A recent study from our laboratory has demonstrated that C57BL/6 male mice that are chronically injected with nicotine develop a profound tolerance to nicotine that is not associated with changes in brain nicotinic receptors. We have proposed that alterations in the secretion of corticosterone (CCS) may regulate tolerance development in chronically injected animals. In the present study we have directly tested this hypothesis. Female DBA/2 mice were injected three times each day for 12 days with saline or 2 mg/kg nicotine. Blood samples were collected at various time points during the course of treatment and plasma CCS levels were determined. The animals were divided into two groups following the last injection on day 12. The first group of animals was tested for nicotine-induced release of corticosterone on day 13 of the experiment and then sacrificed. The brains of these animals were subsequently used to measure nicotinic receptor binding. The second group of animals was adrenalectomized (ADX) or sham-operated on day 13 of the experiment and tested for nicotine sensitivity on day 14 of the experiment. Plasma CCS levels were significantly elevated in animals that were chronically injected with nicotine (versus saline controls) by the fourth day of the experiment. Chronic nicotine-injected animals were tolerant to nicotine-induced CCS release. Animals that were chronically injected with nicotine and sham-operated were tolerant to acute nicotine challenge; however, tolerance to nicotine was not detected in ADX animals. These data support the hypothesis that the capacity to release CCS may underscore the expression of tolerance to nicotine in chronically injected animals.


Desmethylimipramine attenuates cocaine withdrawal in rats. Depression and anhedonia are two major symptoms of cocaine withdrawal in humans. Hence, pharmacological treatments effective in depression might also alleviate the symptoms of cocaine withdrawal. In the present study, the effects of acute and repeated administration of a tricyclic antidepressant, desmethylimipramine (DMI), were investigated in naive and cocaine-withdrawing rats. An animal model of cocaine withdrawal was used that employs the elevation in intracranial self-stimulation (ICSS) thresholds following the termination of prolonged periods of cocaine self-administration as a measure of an animal's "anhedonic" state. The influence of chronic DMI treatment on beta-adrenergic receptor binding and affinity was also correlated with the behavioral signs of cocaine withdrawal. Neither acute nor repeated DMI treatment influenced reward functions in rats that were not undergoing cocaine withdrawal. However, repeated DMI treatment significantly down-regulated beta-adrenergic receptors, and shortened the duration of the post-cocaine "anhedonia" (elevation in thresholds). Furthermore, the magnitude of the beta-adrenergic receptor down-regulation correlated significantly with the degree of effectiveness of DMI treatment in reversing the post-cocaine "anhedonia". However, chronic DMI treatment did reduce the amount of cocaine self-administered by the animals. The reversal of the post-cocaine anhedonia in this animal model of cocaine withdrawal by chronic DMI treatment demonstrates the potential usefulness of the model in identifying new pharmacotherapies for cocaine withdrawal. In addition, the results indicate that tricyclic antidepressants may be able to ameliorate some of the symptoms of cocaine withdrawal.


Anxiolytic effects of nitrous oxide in mice in the light-dark and holeboard exploratory tests. To investigate anxiolytic effects of nitrous oxide (N2O), male mice were tested in two exploratory models--a two-chambered light-dark (L-D) unit and a holeboard. Tests were conducted inside a glovebag through which one of three mixtures of N2O and oxygen (25, 50 and 75% N2O) or room air (RA) was circulated at a flow rate of 10 l/min. The principal findings in the L-D unit were a concentration-related increase in number of interdepartmental transitions and a generalized increase in time spent on the light side. Nitrous oxide effectively elevated transitions in the L-D unit at a lower concentration (25% N2O) than was required to increase locomotor activity in an open field (50% N2O), suggesting that these two measures are at least partially independent; transitions might reflect a specific exploratory component of locomotor behavior. In the holeboard test, a concentration-related increase in number of head dips was observed. Pretreatment with naltrexone-HCl or saline vehicle revealed a contribution by an endogenous opioid-linked locomotor stimulant effect in some measures. A dose-related reversal by flumazenil of 50% N2O-induced shifts in number of head dips and time spent head-dipping implicates a benzodiazepine receptor. Both paradigms, in particular the holeboard, should prove useful in future N2O research.


Effects of physostigmine and scopolamine on rats' performances in object-recognition and radial-maze tests. The effects of physostigmine and scopolamine were evaluated on working memory of rats in object recognition and radial-maze tests. Three doses of physostigmine hemi-sulfate (Phys: 0.05, 0.10 and 0.20 mg/kg), five doses of scopolamine hydrobromide (Scop: 0.125, 0.25, 0.5, 1.0 and 2.0 mg/kg), and one dose of scopolamine methylbromide (Mscop: 2.0 mg/kg) were used. In object recognition test, rats were submitted to three or four intertrial delay conditions (1-min, 15-min and either 60-min or 24-h). The higher doses of Scop (1.0 and 2.0 mg/kg) in 1-min and 15-min delay and of Phys (0.20 mg/kg) in 1-min delay impaired discrimination between new and familiar objects. Mscop impaired discrimination between objects in 60-min but not in 1-min and 15-min delay. This effect may be state dependent. Radial-maze learning was impaired by the lower doses of scopolamine (0.25 and 0.50 mg/kg) which had no effect in object recognition test. These results show that in our conditions, object recognition is less sensitive than radial-maze test to cholinergic drugs.