The effect of Mycobacterium tuberculosis on the susceptibility of human cells to the stimulatory and toxic effects of tumour necrosis factor. It has previously been shown that the inherently tumour necrosis factor-alpha (TNF-alpha)-sensitive L929 murine fibroblast cell line becomes much more sensitive to the cytotoxic effect of this cytokine after exposure to Mycobacterium tuberculosis in culture. In this study it is now shown that normal human cells of types likely to be involved in tuberculous lesions are affected in a similar way. Growth of normal human fibroblasts is usually stimulated by TNF-alpha in vitro, but after exposure to M. tuberculosis or to extracts of this organism, these cells are killed rather than stimulated by subsequent exposure to TNF-alpha. Similarly, human endothelial cells become susceptible to doses to TNF-alpha which do not normally affect viability. Moreover this enhancement of sensitivity to TNF-alpha is not confined to its toxicity. Endothelial cells and HeLa cells exposed to M. tuberculosis express increased levels of ICAM-1 after subsequent exposure to TNF-alpha, implying synergy between the two stimuli. It is suggested that these effects contribute to the ability of M. tuberculosis to distort the normal protective role of TNF-alpha so that the cytokine becomes detrimental to the host.


Mobilization of circulating haemopoietic cells (blood stem cells) by GM-CSF in patients with malignancies. Autologous reinfusion of circulating haemopoietic progenitor and stem cells (blood stem cell transplantation) has emerged as an alternative to autologous bone marrow transplantation in a variety of malignant diseases. Major obstacles associated with harvest of blood stem cells by leukapheresis are: 1. relatively high costs, and 2. discomfort caused to the patient, as generally five to ten settings of leukapheresis are necessary to harvest a number of blood stem cells sufficient for haemopoietic restitution following myeloablative therapy. GM-CSF recently has been shown to effectively increase circulating haemopoietic cells, when given subsequent to even highly-toxic therapy. This report summarizes our data on mobilization of blood stem cells by GM-CSF cells in multiple myeloma patients.


Liquid chromatographic purification and detection of anabolic compounds. The role of liquid chromatography within methods of analysis for steroids, related compounds and beta-agonists in biological samples is discussed. Special attention is given to the application of liquid chromatography in sample preparation and extract clean-up. Different forms of liquid chromatography, including immunoaffinity chromatography, are compared and evaluated. Methods for confirmation based on gas chromatography-mass spectrometry and cryotrapping Fourier transform infrared spectrometry are discussed.


Determination of tranquilisers and carazolol residues in animal tissue using high-performance liquid chromatography with electrochemical detection. A multi-residue method for the determination of tranquiliser residues in animal tissue is described. The procedure may be used to determine residues of the tranquilisers acepromazine, azaperone, chlorpromazine, haloperidol, propionylpromazine, xylazine, the metabolite of azaperone, azaperol, and the beta-adrenoreceptor blocking agent carazolol. Existing methods of analysis for tranquilisers are based on ultraviolet and fluorescence detection and have been used for pig kidney analysis. Determination in this method was by high-performance liquid chromatography with electrochemical detection in the screen mode. The enhanced selectivity offered by the electrochemical detector allowed determination in liver extracts, which often give rise to more interferences on chromatographic traces when using conventional methods of detection. The method offers up to a ten-fold improvement in limits of determination over methods using ultraviolet and fluorescence detection. Recoveries and coefficients of variation have been determined in the range 2-25 micrograms/kg in pig kidney and liver. This electrochemical detection method has been used to measure residues in routine surveillance programmes.


[Pharmacology of cellular ischemia].

[Pharmacology of cellular ischemia]. Knowledge of cellular disturbances provoked by an ischemic aggression conditions the use of a pharmacologic strategy that could possibly protect the cell from necrosis. Whatever the type of cell, the basic mechanisms are very similar: energy failure, acidosis, loss of electrolytic homeostasis, particularly of calcium, formation of free radicals and, of more recent knowledge, genetic induction. Different molecules have been shown to be effective at each of these stages in one or other of the many experimental models available. The therapeutic approach is not very forthcoming at present but the field of applications is vast. Ischemic disease is not restricted to cerebral or cardiac ischemia and, although the lesions are mainly those of senescence, it is observed in other etiologic frameworks, if only in the perinatal period. Finally, the great increase in the use of organ transplants opens up another field of application with research on the best method for organ preservation and optimization of its acceptance by the host organism.


Comparative study of the H2-receptor antagonists cimetidine, ranitidine, famotidine and nizatidine on the rabbit stomach fundus and sigmoid colon. The H2-receptor antagonists, cimetidine, ranitidine, famotidine and nizatidine, were tested for their effect on the isolated smooth muscle strips from the rabbit stomach fundus and sigmoid colon. These H2-receptor antagonists were found to possess a concentration-dependent contractile effect on the above smooth muscle preparations and the order of potency was: ranitidine = nizatidine > famotidine > cimetidine. In addition, the smooth muscle preparations from the sigmoid colon were significantly more sensitive to the above compounds than the smooth muscle preparations from the stomach fundus.


Studies on the anti-allergic mechanism of glucocorticoids in mice. Glucocorticoids inhibit IgE antibody-mediated passive cutaneous anaphylaxis (PCA) and chemical mediator-induced cutaneous reactions elicited in the mouse ear. In the present study, we investigated the effect of actinomycin D, a protein synthesis inhibitor, on dexamethasone-caused inhibition of PCA and histamine-induced cutaneous reaction in the mouse ear. Tyrosine aminotransferase (TAT) activity in the liver, which was estimated as an index for protein synthesis, significantly increased by the administration of hydrocortisone, prednisolone and dexamethasone. Significant increase in TAT activity was observed from 2 h after glucocorticoid administration and peaked at 4 h, and declined gradually thereafter. Cycloheximide even at high doses of 100 and 300 mg/kg failed to affect the increase in TAT activity by dexamethasone. On the contrary, actinomycin D at doses of 1 and 10 mg/kg abrogated the TAT activity increase by dexamethasone almost completely. Treatment with 1 mg/kg of actinomycin D, however, failed to affect the inhibition of PCA and histamine-induced cutaneous reaction by dexamethasone. These results suggest that glucocorticoids exhibit their inhibitory action of PCA and chemical mediator-induced cutaneous reactions in mice through a mechanism resistant to actinomycin D treatment.


A method to simultaneously investigate histamine-induced cyclic AMP and aminopyrine accumulation in isolated gastric mucosal cells from human biopsies. A method has been developed to simultaneously measure two parameters of histamine-induced gastric secretion, cyclic AMP and aminopyrine accumulation, in gastric mucosal cells from human biopsies. Histamine stimulated cyclic AMP and aminopyrine accumulation with different time courses. Cyclic AMP production reached a maximum at 30 min, whereas maximal aminopyrine accumulation was obtained after the cells had been incubated for 90 min in presence of 100 mcM histamine. Histamine was more potent in stimulating aminopyrine than cyclic AMP accumulation. The ED50 values for histamine-induced aminopyrine accumulation were estimated to be 0.88 +/- 0.02 and 25.53 +/- 8.75 mcM for cyclic AMP production, respectively. The aminopyrine accumulation was more than half-maximally increased at 1 mcM histamine without significant effects on the cyclic AMP basal level. It remains to be elucidated whether this finding indicates, besides cyclic AMP, the involvement of calcium in histamine stimulus. The histamine H2-receptor antagonists cimetidine and ranitidine inhibited both in vitro parameters, whereas the gastric proton pump inhibitor omeprazole only affected aminopyrine accumulation. Our method might be a valuable tool for in vitro pharmacological and clinical investigations on histamine-induced gastric secretion in human biopsies.


Possible role of histamine in pathogenesis of autoimmune diseases: implications for immunotherapy with histamine-2 receptor antagonists. The immunosuppressive chemical drugs cyclosporine A (CsA) and methotrexate (Mx) have recently been shown to be of benefit in several different diseases of autoimmune origin. Cellular immune responses may play a major role in autoimmunity as autoreactive T lymphocytes appear to recognize autoantigens and major histocompatibility complex (MHC) class II restriction molecules presented by non-immune, aberrant cells, subsequently leading to damage on healthy tissues. Psoriasis is suggested to be an autoimmune disease and in severe, uncontrollable psoriasis CsA and Mx are of value in reducing disease activity. Histamine is suggested to be involved in the pathogenesis of psoriasis and the histamine-2 receptor antagonist ranitidine has been shown to be of value to reduce severe psoriatic disease. The finding that CsA and Mx efficiently reduce histamine formation and release raises the possibility, that histamine is one of the molecules involved in pathogenesis of autoimmune diseases. T cell mediated regulation and suppression of autoreactive T cells seem to be ineffective in controlling the enhanced immune reaction in patients where the discrimination between self and non-self is changed. A consequence of this may be induction of interferon-gamma (IFN-g) production and release by cytotoxic T cells, subsequently leading to expression of MHC II molecules on non-immune tissues. As immunotherapy may be of value in some autoimmune diseases the use of histamine-2 receptor antagonists should be evaluated in patients where conventional therapy is ineffective to reduce disease activity.


Genetic and physical analysis of the rice bacterial blight disease resistance locus, Xa21. Nearly isogenic lines (NILs) of rice (Oryza sativa) differing at a locus conferring resistance to the pathogen Xanthomonas oryzae pv. oryzae were surveyed with 123 DNA markers and 985 random primers using restriction fragment length plymorphism (RFLP) and random amplified polymorphic DNA (RAPD) analysis. One chromosome 11 marker (RG103) detected polymorphism between the NILs that cosegregated with Xa21. All other chromosome 11 DNA markers tested were monomorphic between the NILs, localizing the Xa21 introgressed region to an 8.3 cM interval on chromosome 11. Furthermore, we identified two polymerase chain reaction (PCR) products (RAPD2148 and RAPD818) that detected polymorphisms between the NILs. Genomic sequences hybridizing with RAPD818, RAPD248 and RG103 were duplicated specifically in the Xa21 NIL. All three markers cosegregated with the resistance locus, Xa21, in a F2 population of 386 progeny. Based on the frequency with which we recovered polymorphic Xa21-linked markers, we estimated the physical size of the introgressed region to be approximately 800 kb. This estimation was supported by physical mapping (using pulsed field gel electrophoresis) of the sequences hybridizing with the three Xa21-linked DNA markers. The results showed that the three Xa21-linked markers are physically close to each other, with one copy of the RAPD818 sequences located within 60 kb of RAPD248 and the other copy within 270 kb of RG103. None of the enzymes tested generated a DNA fragment that hybridized with all three of the markers indicating that the introgressed region containing the resistance locus Xa21 is probably larger than 270 kb.


[Role of glutamate intracortical connections in conditioned reflex activity]. The effects of iontophoretic application of glutamate and its blockers on neuronal activity of the sensorimotor cortex were studied in cat during fulfillment of conditioned instrumental placing reflex. 64 neurons were investigated. Application of glutamate caused reliable facilitation of neuronal impulse reactions to the conditioned stimulus. The facilitation appeared some seconds after beginning of the application of glutamate and continued for 5-10 min after cessation of the iontophoretic application. The similar inhibitory effect in neuronal activity was observed with application of APV, kinurenate, ketamine. It is suggested that the NMDA receptors under natural conditions take part in facilitation of the synaptic transmission in glutamatergic intracortical pathways.


[Study of the recovery rate of non-NMDA desensitized receptors of hippocampal neurons using paired and rhythmic application of glutamate]. The new technique has been used to realize paired short-term application of glutamate to whole dialyzed neuron. Desensitization of receptors via first application of glutamate resulted in incomplete recovery of the current evoked by the second application if interval between both applications was less than 160 ms. The recovery time constant of the current was found to be 44 ms at single exponential approximation. It is close to the mean desensitization time constant of the current evoked by single prolonged application of glutamate. Rhythmic application of glutamate resulted in a rapid fall of the mean current amplitude at frequencies over 10 Hz. Data obtained by the authors confirm the known concept of desensitization of non-NMDA receptors as a relatively slow conformation of the receptor-channel complex.


No constant relationship between islet amyloid polypeptide (IAPP) and insulin expression in insulinomas. The relationship between insulin and islet amyloid polypeptide (IAPP) expression was studied at the level of RNA and peptide in 3 patients operated on for insulinoma. Two patients had a solitary tumour; one patient suffered from the MEN-I syndrome. In the 3 tumours, as in normal pancreas, the same 2 IAPP-specific mRNA species, approximately 1600 and 2100 nucleotides, respectively, were detected. In 2 patients, the IAPP mRNA concentration of the tumour was lower than the insulin mRNA concentration; in the third patient, however, the specific IAPP hybridization signal was at least equal to that for insulin. Amyloid deposits were found in one solitary tumour and in the tumour from the MEN-I patient, both staining strongly positive with anti-IAPP antibodies; cytoplasmatic IAPP was weak. In conclusion, at least in some insulinomas, no constant relationship exists between insulin and IAPP expression.


Prenatal exclusion of haemophilia A and carrier testing by direct detection of a disease lesion. A novel mutation was detected in the Factor VIII gene of a sporadic case of severe haemophilia A. The lesion, a CGA-->TGA transition, converts Arg 795 to Term and adequately accounts for the severe phenotype observed. PCR/direct sequencing was used to confirm the carrier status in the mother. Exclusion of haemophilia A in an at-risk pregnancy was then achieved by demonstration of the absence of this lesion in fetal DNA from a chorionic villus sample. The mutation was also detectable by chemical cleavage of mismatch (CCM), which both confirmed the prenatal diagnosis and established the carrier status of the proband's sister. This example therefore serves to illustrate the potential of direct gene analysis in sporadic cases of haemophilia A and/or in families uninformative for known RFLPs.


Spinal antinociceptive effects of [D-Ala2]deltorphin II, a novel and highly selective delta-opioid receptor agonist. Pharmacological assays in isolated tissues and binding tests have recently shown that two peptides, with the sequence Tyr-D-Ala-Phe-Asp-(or Glu)- Val-Val-Gly-NH2, isolated from skin extracts of Phyllomedusa bicolor and named [D-Ala2]deltorphin I and II, respectively, possess a higher affinity and selectivity for delta-opioid receptors than any other known natural compound. Since much evidence supports the role of spinal delta-opioid sites in producing antinociceptive effects, we investigated whether analgesia might be detected by direct spinal cord administration of [D-Ala2]deltorphin II (DADELT II) in the rat. The thermal antinociceptive effects of intrathecal DADELT II and dermorphin, a potent mu-selective agonist, were compared at different postinjection times by means of the tail-flick test. The DADELT II produced a dose-related inhibition of the tail-flick response, which lasted 10-60 min depending on the dose and appeared to be of shorter duration than the analgesia produced in rats after intrathecal injection of dermorphin (20-120 min). The analgesic effect of infused or injected DADELT II was completely abolished by naltrindole, the highly selective delta antagonist. These results confirm the involvement of delta receptors in spinal analgesic activity in the rat.


Prenatal diagnosis of metabolic diseases on chorionic villi obtained before the ninth week of pregnancy. Nine pregnancies at risk for various metabolic disorders were monitored by prenatal diagnosis on chorionic villi obtained between the sixth and ninth weeks of pregnancy. A diagnosis of an affected fetus was made in five cases (Sandhoff, Tay-Sachs (2), Pompe's, GM1), while metachromatic leukodystrophy, GM1 (2), and Pompe's were excluded in four cases. It is concluded that chorionic villi are a reliable tissue for prenatal diagnosis of metabolic disorders also when obtained before the ninth week.


Sex differences in the effects of Tyr-MIF-1 on morphine- and stress-induced analgesia. There is evidence suggesting that the endogenous tetrapeptide, Tyr-MIF-1 (Tyr-Prol-Leu-Gly-amide), has antagonistic or modulatory effects on opioid-mediated analgesia. There is also substantial evidence for sex differences in opioid effects, whereby male rodents display greater levels of opioid-mediated analgesia than females. In the present study, determinations were made of the effects of Tyr-MIF-1 on morphine- and restraint stress-induced opioid analgesia in adult male and female deer mice, Peromyscus maniculatus. Intraperitoneal treatment with Tyr-MIF-1 (0.10-10 mg/kg) reduced morphine- and stress-induced analgesia in both male and female mice, with Tyr-MIF-1 having markedly greater antagonistic effects in male than female mice. These results indicate that there are sex differences in the modulatory (antiopiate) effects of Tyr-MIF-1 on opioid-mediated analgesia.


Somatostatin as a mediator of the effect of neurotensin on pentagastrin-stimulated acid secretion in rats. Neurotensin and somatostatin have both been shown to inhibit gastric acid secretion, but no interaction between these peptides has been demonstrated. To determine whether somatostatin might be a mediator of neurotensin's effect on pentagastrin-stimulated gastric acid secretion, we performed the following three experiments. First, we collected 0.2-ml samples of portal venous blood as frequently as every 5 min, and we confirmed a significant release of somatostatin-like immunoreactivity into portal venous blood during neurotensin-induced inhibition of acid secretion. This release of somatostatin-like immunoreactivity and inhibition of acid secretion were only seen in pentobarbital-anesthetized rats, but no sustained release of somatostatin-like immunoreactivity or inhibition of acid secretion occurred in urethane-anesthetized animals. In the second experiment, we analyzed portal plasma by high pressure liquid chromatography, and found that portal somatostatin-like immunoreactivity in blood collected during neurotensin infusion was composed of a single peak corresponding to somatostatin-14. In the third experiment, we found that infusion of antibody to somatostatin prevented neurotensin from inhibiting pentagastrin-stimulated acid secretion. Taken together, these data show that somatostatin, possibly from the stomach itself, is a necessary mediator of neurotensin's inhibitory effect in pentobarbital-anesthetized rats.


Growth of axons through a lesion in the intact CNS of fetal rat maintained in long-term culture. The ability of neurons in the central nervous system (CNS) to grow through a lesion and restore conduction has been analysed in developing spinal cord in vitro. The preparation consists of the entire CNS of embryonic rat, isolated and maintained in culture. Conduction of electrical activity and normal morphological appearance (light microscopical and electron microscopical) were maintained in the spinal cord of such preparations for up to 7 d in culture. A complete transverse crush of the spinal cord abolished all conduction for 2 d. After 3-5 d, clear recovery had occurred: electrical conduction across the crush was comparable with that in uninjured preparations. Furthermore, the spinal cord had largely regained its gross normal appearance at the crush site. Axons stained in vivo by carbocyanine dyes had, by 5 d, grown in profusion through the lesion and several millimetres beyond it. These experiments, like those made in neonatal opossum (Treherne et al. 1992) demonstrate that central neurons of immature mammals, unlike those in adults, can respond to injury by rapid and extensive outgrowth of nerve fibres in the absence of peripheral nerve bridges or antibodies that neutralize inhibitory factors. However, unlike the opossum, in which outgrowth occurred at 24 degrees C, although there was prolonged survival of rat spinal cords at this temperature, outgrowth of axons across the lesion required a temperature of 29 degrees C. With rapid and reliable regeneration in vitro it becomes practicable to assay the effects of molecules that promote or inhibit restoration of functional connections.


K(+)-channel blockers restore synaptic plasticity in the neuromuscular junction of dunce, a Drosophila learning and memory mutant. The effects of K(+)-channel blockers on synaptic transmission in dunce (dnc), a Drosophila learning and memory mutant, were investigated. Larvae dnc mutants lack facilitation and post-tetanic potentiation (PTP) at their motor end-plates; dnc mutants are also deficient in a form of phosphodiesterase, and exhibit abnormally high levels of cyclic adenosine 3',5'-monophosphate (cAMP). A two-microelectrode voltage-clamp was used to record end-plate currents and spontaneous end-plate currents from longitudinal ventrolateral third-instar larval muscle. The K(+)-channel blockers 3,4-diaminopyridine (3,4-DAP) and tetraethylammonium (TEA), at micromolar concentrations, caused a reversible decrease in end-plate current amplitudes both in wild-type and mutant end-plates. In the presence of blockers, a period of high-frequency stimulation (tetanus) of the nerve gave way to a transient increase in the end-plate currents of dnc mutants resembling facilitation and PTP in normal end-plates; 3,4-DAP and TEA also restored facilitation and PTP in normal end-plates after incubation with a non-hydrolysable analogue of cAMP (8Br-cAMP). It is suggested that a specific K+ conductance might be relevant to the lack of synaptic plasticity at the dnc neuromuscular synapses.


A kin selection model for the evolution of virulence. The costs and benefits of parasite virulence are analysed in an evolutionarily stable strategy (ESS) model. Increased host mortality caused by disease (virulence) reduces a parasite's fitness by damaging its food supply. The fitness costs of high virulence may be offset by the benefits of increased transmission or ability to withstand the host's defences. It has been suggested that multiple infections lead to higher virulence because of competition among parasite strains within a host. A quantitative prediction is given for the ESS virulence rate as a function of the coefficient of relatedness among co-infecting strains. The prediction depends on the quantitative relation between the costs of virulence and the benefits of transmission or avoidance of host defences. The particular mechanisms by which parasites can increase their transmission or avoid host defences also have a key role in the evolution of virulence when there are multiple infections.


Nonlinear mechanical responses of mouse cochlear hair bundles. The stiffness of sensory hair bundles of both inner (IHC) and outer (OHC) hair cells was measured with calibrated silica fibres in mouse cochlear cultures to test the hypothesis that the mechanical properties of the hair bundle reflect processes underlying mechanotransduction. For OHCs, the displacement of the hair bundle relaxed with time constants of 6 ms for displacements which open transducer channels and 4 ms for displacements which close the channels. The corresponding values of the time constants for IHCs were 10 ms and 8 ms, respectively. A displacement-dependent change in the stiffness of the hair bundle was not observed when the bundle was displaced orthogonally to the direction of excitation. The stiffness of the hair bundle as a function of nanometre displacements from the resting position was remarkably nonlinear. The stiffness declined to a minimum from the resting stiffness by about 12% for OHCs and 20% for IHCs when the hair bundle was displaced by about 20 nm in the excitatory direction, and it increased by a similar amount when the bundle was displaced by 20 nm in the inhibitory direction. The displacement at which the stiffness reached a minimum was within the most sensitive region of the hair-cell transducer function (receptor potential as a function of hair-bundle displacement), and the displacement at which the stiffness reached a maximum was at the point of saturation of the transducer function in the inhibitory direction. The nonlinear displacement-dependent compliance change is reversibly abolished, and the time constant of relaxation of the bundle for excitatory displacements is reversibly reduced, when mechanotransduction is blocked by the addition of either neomycin sulphate or cobalt chloride to the solution bathing the hair cells. The displacement-dependent compliance change was not apparently reduced when the receptor potential was attenuated through the substitution of sodium in the bathing solution with a less permeant cation, tetraethylammonium. These findings suggest that the nonlinear mechanical properties of the hair bundle are associated with aspects of the hair-cell mechanotransducer process. The mechanical properties of the hair bundle are discussed in relation to the 'gating-spring' hypothesis of hair-cell transduction.


Kinetics of intracellular calcium release by inositol 1,4,5-trisphosphate and extracellular ATP in porcine cultured aortic endothelial cells. Quantitative, time-resolved measurements have been made of intracellular Ca ion release by inositol 1,4,5-trisphosphate (InsP3) and extracellular ATP in porcine aortic endothelial cells in tissue culture. Intracellular free [Ca] was detected with the calcium dye fluo-3 and InsP3 released intracellularly by photolysis of 'caged' InsP3 in whole-cell voltage-clamped aortic endothelial cells. A rise of [Ca] was recorded at InsP3 concentrations greater than 0.2 microM. The timecourse at low InsP3 concentrations comprised a delay of mean 300 ms (range 266-330 ms), a peak in 2-3 s before declining with a half-time of 5-10 s. The delay and time-to-peak decreased with increasing concentrations of InsP3 over the range 0.2-5 microM. At very high concentrations of InsP3 (> 5 microM), the delay in the Ca response was short, always less than 20 ms. The results are consistent with a direct binding and gating action of InsP3 on the Ca channel of the cellular store. Following InsP3 action there is a refractoriness of the InsP3 Ca release process which recovers with a timecourse of half-time about 30 s. A comparison can be made between the timecourse of InsP3 and extracellular ATP actions. High concentrations of ATP (500 microM) acted with a delay of mean 1.8 s (range 1.2-2.5 s), whereas even moderate concentrations of InsP3 acted much more quickly, suggesting that there are slow coupling steps before or during the production of InsP3 in response to extracellular ATP. Both ATP and InsP3 evoked an increase in membrane conductance to K+, probably via Ca.


Detection and processing of vertical disparity by the human observer. Based on the distinction between uniocular vertical magnification and vertical disparity, the induced size effect experiments were reinterpreted and new experiments done to show that vertical disparity signals can produce other stereoptic depth effects. The direction and efficiency of utilization of vertical disparity signals depend on the quadrant of the visual field and the stimulus position within it.


Modelling the immune response to malaria with ecological concepts: short-term behaviour against long-term equilibrium. A model for the human immune response to the malaria parasite Plasmodium falciparum is used to analyse the dynamics of an infection within an individual patient. Previous models either looked at competition between two parasite genotypes or at one parasite clone and the immune response to it. This model describes the course of an infection caused by the blood stages of two parasite genotypes differing in reproductive rate and in the immune response they elicit. The interactions between the genotypes can be interpreted as exploitative competition for red blood cells. Interactions between omnipotent immune cells and parasites resemble a predator-prey relation. In analysing these kinds of models, classical theoretical ecology usually deals with long-term behaviours, i.e. looks for equilibria and conditions for coexistence. However, especially in endemic regions with ongoing transmission, an equilibrium state of infections is unlikely. When reinfections with another parasite genotype were considered, the short-term dynamics of the infection changed dramatically, depending on which genotype was first, when the second one appeared, and what kind of immune response was elicited. If the slow development of immunity to malaria really is due to its genotype specificity, the effects of superinfections will be of great importance.


Statistical geometry of pancreatic islets. Quantitative histomorphometric studies of the dynamics of growth and development of pancreatic islets in normal and pathological states pose substantial methodological and conceptual problems. We address these problems with the geometry of random fractals, and apply our methods to the analysis of islet regeneration in the alloxan-treated guinea-pig. In both experimental islet-regenerated and control animals, islet centres are found to cluster in similar fractal subsets of dimension strictly less than 3, in agreement with the postulated origin of islets along a system of ductules, and suggesting that regeneration follows the same mathematical dynamics as original islet formation.


The glial spike theory. I. On an active role of neuroglia in spreading depression and migraine. The propagation mechanism of spreading depression (SD), which has been implicated in the pathophysiology of the neurological auras of migraine, remains enigmatic but is widely believed to depend primarily upon the behaviour of assemblies of neurons. It is proposed here, based upon a program of theoretical research, that the most essential constituent of SD is a slowly propagating, regenerative event in the neuroglial compartment. By altering the neuronal microenvironment, this glial spike helps trigger and coordinate the neuronal depolarization of SD; the glial spike is in turn facilitated by neuronally released agents acting at the neuroglial plasma membrane. The conduction velocity-determining propagation mechanism of SD is further proposed to be a wave of intracellular Ca(2+)-induced Ca2+ release (cytocal wave) that travels through the glial compartment of nervous tissue. Some implications for the improved understanding and clinical management of migraine are suggested. Excitability of glial cells of vertebrates has until now been demonstrated only in vitro, and its physiological significance has remained unknown. This work identifies a macroscopic reaction of neuronal tissue, known from the in vivo vertebrate brain for over 45 years, as a manifestation of neuroglial excitability.


A computational model of the analysis of some first-order and second-order motion patterns by simple and complex cells. Although spatio-temporal gradient schemes are widely used in the computation of image motion, algorithms are ill conditioned for particular classes of input. This paper addresses this problem. Motion is computed as the space-time direction in which the difference in image illuminance from the local mean is conserved. This method can reliably detect motion in first-order and some second-order motion stimuli. Components of the model can be identified with directionally asymmetric and directionally selective simple cells. A stage in which we compute spatial and temporal derivatives of the difference between image illuminance and the local mean illuminance using a truncated Taylor series gives rise to a phase-invariant output reminiscent of the response of complex cells.


Dopamine autoreceptor agonists in the treatment of schizophrenia and major depression. Dopamine autoreceptor agonists reduce the firing rate, synthesis, and release of dopamine in dopaminergic neurons by means of a negative feedback mechanism via stimulation of autoreceptors. Moreover, dopamine autoreceptor agonists are able to stimulate supersensitive but not normosensitive postsynaptic receptors. For dopamine autoreceptor agonists, therapeutic effects by readjustment of excessive or deficient dopaminergic function have been postulated for positive and negative schizophrenic symptomatology as well as for subtypes of depressive disorders. Investigations on the therapeutic effects of autoreceptor-nonselective dopamine agonists in schizophrenia or depression have yielded inconsistent results. In order to reduce the excess of central dopaminergic activity postulated by the dopamine hypothesis of schizophrenia, dopamine autoreceptor agonists have been tested in open clinical trials in positive schizophrenic symptomatology. However, administration of selective dopamine autoreceptor agonists like talipexole or roxindole did not result in a significant improvement of positive psychotic symptoms. In negative schizophrenic symptomatology, a dopamine deficit rather than an excess has been hypothesized. Current evidence from pilot studies suggests that dopamine autoreceptor agonists like roxindole may produce a minor to moderate improvement of symptoms like affective flattening, depressed mood, alogia, and avolition, possibly by stimulation of supersensitive postsynaptic dopamine receptors. For certain subgroups of depression, a reduction of functional dopamine activity has been postulated. In an open pilot study in patients with a major depression, roxindole demonstrated antidepressive properties comparable to those of standard antidepressants, justifying further double-blind controlled trials against reference drugs.


[Paroxysmal neurological manifestations disclosing panic attacks]. Thirty-seven patients presented with paroxysmal neurological manifestations attributed to anxiety attacks. The manifestations included loss of consciousness, focal sensorimotor deficits, diffuse dysesthaesiae, visual disorders and tremor. They lasted 10 to 45 minutes and occurred once per day to once per week. Organic pathology was dismissed on the basis of normal examinations and atypical course. In all patients questioning revealed symptoms that were those of acute anxiety. The fact that these attacks took place in suggestive (circumstances e.g. in crowds and car driving), and that they could be induced by challenge tests hyperpnoea, infusion of lactate) suggested that these disorders were consecutive to panic attacks.


[Therapeutic maintenance and tolerance of sulfasalazine in rheumatoid polyarthritis. Retrospective study of 95 patients]. This retrospective study evaluated treatment with sulfasalazine (SAS) in a mean dosage of 2.1 g/day in 95 patients with rheumatoid arthritis (RA) who were followed-up for 3 months to 4 years. Mean disease duration was 7 years; 79 patients had previously received at least one disease-modifying drug. Four per cent of patients were lost to follow-up. Mean duration of treatment was 15 months (3 weeks-50 months). Treatment continuation rates were 57% at one year, 40% at two years, and 26% at three years. Reasons for discontinuation of SAS included adverse effects (n = 24), inefficacy (n = 33), and death unrelated to SAS therapy (n = 2). In four patients, SAS was discontinued within three months of the first dose because of a severe adverse effect (diffuse erythematous rash, diffuse bullous rash, hepatitis with jaundice, agranulocytosis). SAS-induced biologic markers for lupus were seen in one patient. Furthermore, 12% of evaluable patients developed antinuclear antibodies during SAS therapy. The SAS treatment continuation rate was higher (p = 0.05) among patients under 40 years of age (n = 18) than among older patients. This difference was due to a correlation between age and tolerance with less SAS-induced side effects in patients under 40 years of age (p = 0.03). The SAS treatment continuation rate was unrelated to the duration of rheumatoid arthritis or number of previous maintenance treatments. This study suggests that rheumatoid arthritis patients under 40 years of age exhibit better tolerance to SAS therapy.


A novel model to assess developmental toxicity of dihaloalkanes in humans: bioactivation of 1,2-dibromoethane by the isozymes of human fetal liver glutathione S-transferase. Glutathione S-transferase (GST) isozymes from human fetal liver (16-18 weeks gestation) were purified by affinity chromatography followed by ion-exchange high performance liquid chromatography (HPLC). The purified isozymes were used to investigate toxicity of 1,2-dibromoethane(EDB) in an in vitro model of rat embryos in culture as passive targets. At least five isozymes of GST were found in the human fetal liver. Two anionic forms [pI values 5.5 (P-2) and 4.5 (P-3)] and one basic form [pI value 8.7 (P-6)] were clearly separated. The presence of two near-neutral forms was also identified. All the isozymes of the human fetal liver GSTs tested metabolized EDB (specific activities were 2.1, 7.0, and 2.0 mumol of GSH consumed/min/mg protein for P-2, P-3, and P-6 isozymes, respectively). Covalent binding of EDB to DNA and protein was 144% and 212% higher, respectively, with the P-3 anionic isozyme when compared to the P-6 basic isozyme of GST. No covalent binding to either protein or DNA was observed with the P-2 isozyme. EDB bioactivation by the GST isozyme P-3 (15 units; 1 unit = 1 nmol of GSH consumed/min) resulted in toxicity to cultured rat embryos. Significant reductions of crown rump length, yolk sac diameter, and the composite score of morphological parameters (Brown and Fabro method) were observed. The central nervous system, optic and olfactory systems, and the hind limb were most significantly affected. The results of this investigation suggest that EDB may be classified as a suspected developmental toxicant in humans.


Teratogenic effects of N-nitrosodiethylamine in embryos of the hermaphroditic fish Rivulus marmoratus. Exposure of N-nitrosodiethylamine (NDEA) to hermaphroditic fish (Rivulus marmoratus) embryos induced specific congenital malformations when the chemical was applied to embryos on days 0-6 post morula stage. This sensitive period generally coincided with the known period of organogenesis in this species, and the incidence of anomalies was clearly dose related. These results indicate that NDEA is teratogenic to fish embryos.


N-alkyl-N-nitrosourea induced secondary structural changes in DNA from rat embryos and fetal brains in vivo. N-methyl-N-nitrosourea (MNU) and N-ethyl-N-nitrosourea (ENU) are gestational stage dependent teratogens and transplacental carcinogens capable of inducing neurogenic tumours in rats. Intravenous treatment of gravid Wistar rats showed that MNU is teratogenic but ENU is a transplacental carcinogen and may be a teratogen when administered on day 12 of gestation. Twenty-four hours after single doses of 2, 5, or 10 mg MNU/kg on day 12, dose dependent decreases in embryonic wet weight and total embryonic DNA were observed. Rats similarly treated with 2 and 5 mg MNU/kg showed dose dependent decreases in fetal brain DNA synthesis, DNA content, and wet weight 9 days later. Administration of single ENU doses of 1.5, 3, 6, 12, 48, and 80 mg/kg to day 12 embryos resulted in a dose dependent reduction in [methyl-14C]-thymidine (14C-TdR) incorporation into DNA after 24 h although total DNA amounts and embryonic wet weights were unaffected. Benzoylated DEAE-cellulose (BD-cellulose) chromatography fractionates DNA on the basis of secondary structure by stepwise elution of double-stranded DNA with 1.0 M NaCl solution (SE-DNA) followed by elution of DNA containing single-stranded regions with caffeine solution (CE-DNA). Day 13 embryonic and day 21 fetal brain DNA was monitored by in vivo labelling with [methyl-3H]-thymidine on days 6 and 7 of gestation. Significant reduction in percentages of CE-DNA (%CE-DNA) 24 h after treatment of day 12 embryos with 2, 5, or 10 mg MNU/kg were attributed to the necrotic effect of MNU. Day 12 treatment with MNU produced no change in %CE-DNA values of day 21 fetal brains. A teratogenic dose of 80 mg ENU/kg to day 12 embryos resulted in significantly increased %CE-DNA values compared to controls but no changes were observed after 1.5 to 48 mg/kg. Analysis of the distribution of %CE-DNA values from the 80 mg ENU/kg treated litter showed that the increase in %CE-DNA was due to a second distinct population of embryos with higher %CE-DNA values than controls. Incorporation of 14C-TdR into embryonic and fetal brain DNA demonstrated the effects of treatment with these compounds on DNA synthesis in vivo. The relative %CE-DNA is expressed as the ratio of the percentage of caffeine-eluted 14C-labelled DNA to %CE-DNA (i.e., %CE-14C-DNA:%CE-3H-DNA). In the majority of control embryos the 14C-specific activity of CE-DNA was higher than the 14C-specific activity of SE-DNA.(ABSTRACT TRUNCATED AT 400 WORDS)


Further in vitro and in vivo mutagenicity assays with thiram and ziram fungicides: bacterial reversion assays and mouse micronucleus test. The fungicides thiram and ziram have been assayed in a battery of nine bacterial strains of different genetic specificity. The results obtained suggest the induction of excisable DNA lesion(s), and indicate similar mutability of strains with AT or GC base pairs at target sites. This mutagenic profile is clearly distinct from that of oxidative mutagens, and it does not support the proposed role of oxidative stress in the mechanism of dithiocarbamates mutagenicity in bacteria. Furthermore, the bone marrow micronucleus test has been carried out in B6C3F1 mice with intraperitoneal administration of high grade thiram (12.5-50 mg/kg) and ziram samples (2.5-10 mg/kg in males, and 5-20 mg/kg in females). Thiram produced a significant increase of micronucleated PCEs in male mice sampled 48 h after treatment with 25, 37.5, and 50 mg/kg. No significant increase was detected in treated females. Ziram, tested in a lower range of doses because of its higher toxicity, resulted negative in both sexes. Both the acute toxicity and the ratio polychromatic/normochromatic erythrocytes indicated some sex specificity in the toxic effects induced by these dithiocarbamates in the B6C3F1 mouse.


Reversible sensorimotor impairment following prolonged ventilation with isoflurane and vecuronium for acute severe asthma. A patient with acute asthma developed severe sensorimotor neuropathy while being ventilated with isoflurane and receiving vecuronium and fentanyl. The neuropathy resolved spontaneously within three months of the episode. This unusual complication may result from prolonged use of inhalational anaesthesia or of vecuronium, or both.


Effect of primary phase feline immunodeficiency virus infection on cats with chronic toxoplasmosis. The effect of primary phase feline immunodeficiency virus (FIV) infection on clinical signs, hematological values, Toxoplasma gondii oocyst shedding, T. gondii-specific serology, T. gondii-specific cell-mediated immune responses, non-specific cell-mediated immune responses, and lymphocyte subpopulations from cats with experimentally induced chronic toxoplasmosis was studied. No significant clinical or hematologic abnormalities were noted following inoculation with FIV. T. gondii-specific IgM was significantly increased, concanavalin A, T. gondii tachyzoite antigen and T. gondii secretory antigen induction of lymphocyte transformation were significantly suppressed, and CD4+ cell numbers were significantly decreased following inoculation with FIV. The changes were attributed to FIV effects on the immune system and resultant activated toxoplasmosis.


Use of two virustatica (AZT, PMEA) in the treatment of FIV and of FeLV seropositive cats with clinical symptoms. In the present study the therapeutic efficacy and the side effects of two antiretroviral compounds used in human acquired immunodeficiency syndrome (AIDS) research, 3'-azido-2',3'-dideoxythymidine (AZT, zidovudine, Retrovir) and 9-(2-phosphonylmethoxyethyl)adenine (PMEA), were investigated in the treatment of cats naturally infected with feline immunodeficiency virus (FIV) and cats naturally infected with feline leukemia virus (FeLV). AZT was administered subcutaneously at a dose of 5 mg kg-1 body weight every 12 h and PMEA was administered subcutaneously at a dose of 2.5 mg kg-1 body weight every 12 h during a 3 week hospitalization. The therapeutic efficacy of both compounds was investigated. There was a stronger potency of PMEA than of AZT on the regression of stomatitis in FIV and in FeLV infected cats. In addition, in FIV infection PMEA had a stronger effect on the improvement of the general clinical status. Both antiretroviral compounds were potent agents to improve the immunologic status of FIV infected cats by raising the CD4/CD8 ratio. In FeLV infection PMEA and AZT appeared to reduce antigenemia. The hematological side effects caused by PMEA were severe and stronger than those of AZT. Therefore the advantage of PMEA in clinical and immunologic improvement was diminished by the hematologic disorders, which do not allow long term treatment with this drug in the dose used.


Immunization-induced decrease of the CD4+:CD8+ ratio in cats experimentally infected with feline immunodeficiency virus. In a previous experiment a group of 15 specified pathogen free (SPF) cats were experimentally infected with a Swiss isolate of feline immunodeficiency virus (FIV). A group of 15 SPF cats served as FIV negative controls. Nine cats of each group were vaccinated with a recombinant feline leukemia virus (FeLV) vaccine, six cats in each group with a placebo vaccine. All vaccinated cats developed high antibody titers to FeLV and were protected against subsequent FeLV challenge infection. In both control groups five of six cats became persistently infected with FeLV. Unexpectedly, the primary immune response to the vaccine antigen was significantly higher in the FIV positive group than in the FIV negative. The secondary response was stronger in the FIV negative cats. The goal of the present investigation was to further study the immune response in these 30 cats. They were immunized twice with the synthetic peptide L-tyrosine-L-glutamic acid-poly(DL-alanine)-poly(L-lysine) (TGAL) 21 days apart. Blood samples were collected on four occasions during the immunization process. They were tested for antibodies to TGAL, complete blood cell counts and CD4+, CD8+ and pan-T-lymphocyte counts. The following observations were made: (1) in contrast to the FeLV vaccine experiment, the primary immune response to TGAL was not significantly stronger in the FIV positive cats when tested by enzyme-linked immunosorbent assay (2). The absolute size of the CD4+ lymphocyte population was distinctly smaller in the FIV positive than in the FIV negative cats. The lowest CD4+ values were found in the dually FIV/FeLV infected cats. (3) A population of CD8+ lymphocytes was identified that was characterized by a distinctly weaker fluorescence. The size of this population increased in FIV positive and decreased in FIV negative cats during the TGAL immunization experiment. (4) The CD4+:CD8+ ratio increased in FIV negative cats during TGAL immunization from 1.9 to 2.3. In contrast, in FIV positive animals the CD4+:CD8+ ratio decreased significantly from 1.9 to 1.3 during the same period. From these and earlier data it was concluded that in short-term FIV infection the immune response to T-cell dependent antigens may be increased over that of the controls. Immune suppression develops gradually with duration of the infection. The significant drop of the CD4+:CD8+ ratio over a 5 week immunization period suggests that antigenic stimulation may accelerate the development of immune suppression in FIV positive cats. If this is a general feature, FIV infection may provide a particularly interesting model for studying the pathogenesis of AIDS.


Persistent upregulation of MHC class II antigen expression on T-lymphocytes from cats experimentally infected with feline immunodeficiency virus. A significant elevation in the percentage of CD4+ and CD8+ T-lymphocytes expressing major histocompatibility complex (MHC) Class II antigens was observed in the blood of cats shortly after they were experimentally infected with feline immunodeficiency virus (FIV). In addition to an increase in the relative proportion of T-lymphocytes expressing Class II antigens, there was an increase in the density of Class II antigens on the cell surface. These elevations were still evident at the completion of the 5 month study. A second group of cats that had been infected with FIV for almost 5 years, and with either normal or abnormally low levels of CD4+ T-lymphocytes, had similar elevations in MHC II expression, suggesting that such abnormalities are lifelong. Cats with chronic (2 year) feline leukemia virus (FeLV) infection or dual FIV/FeLV infections also showed similar alterations in MHC II expression on CD4+ and CD8+ T-lymphocytes, suggesting that these alterations were not FIV specific. Feline T-lymphocytes expressed more MHC II antigen and interleukin-2 (IL-2) receptor following stimulation in vitro with conconavalin A and IL-2, demonstrating that feline T-lymphocytes respond to activation signals in a manner similar to T-lymphocytes of other species. However, changes in MHC II expression on T-cells of FIV infected cats were not explainable by viral induced T-cell activation alone, because FIV infected cats with elevated MHC II expression did not have coincident elevations in IL-2 receptor expression.


Interaction of acute feline herpesvirus-1 and chronic feline immunodeficiency virus infections in experimentally infected specific pathogen free cats. Cats with or without chronic feline immunodeficiency virus (FIV) infection were exposed to feline herpesvirus, type 1 (FHV-1). FIV infected cats became sicker than non-FIV infected cats and required more supportive treatment. However, there were no differences in the length of their illness or in the levels and duration of FHV-1 shedding. FHV-1 infection caused a transient neutrophilia at Day 7 with a rapid return to preinfection levels. The neutrophilia coincided with a transient lymphopenia that was accompanied by a decline in both CD4+ and CD8+ T-lymphocytes. A brief decrease in the CD4+/CD8+ T-lymphocyte ratio occurred at Day 14 in both FIV infected and non-infected cats. This decrease was mainly the result of an absolute and transient increase in CD8+ T-lymphocytes. CD4+ and CD8+ T-lymphocyte numbers and CD4+/CD8+ T-lymphocyte ratios returned to baseline within 4-8 weeks in both FIV infected and non-infected cats. FIV infected cats produced less FHV-1 neutralizing antibodies during the first 3 weeks of infection than non-FIV infected animals. The IgM FHV-1 antibody response was depressed in FIV infected cats whereas the IgG antibody response was unaffected. FHV-1 infection evoked a comparable transient loss of lymphocyte blastogenic responses to concanavalin A and pokeweed mitogen in both FIV infected and non-infected cats. However, response to pokeweed mitogen took longer to return to normal in FIV infected animals. Lymphocytes from FIV infected cats had a greater and more sustained proliferative response to FHV-1 antigen than non-FIV infected cats. The ongoing IgG antibody response to FIV was not affected by FHV-1 infection.


[Reading, hearing, understanding].

[Reading, hearing, understanding]. The relationship between reading comprehension, listening comprehension, and two indicators of intelligence (verbal reasoning, speed of information processing) is analyzed on the basis of a hierarchical monistic model. Two tests (reading comprehension, listening comprehension) were administered to 221 4th graders in classroom context at two sessions. Order of administration was balanced. Additionally, verbal reasoning and speed of information processing were assessed, marks in German were collected. On the whole, performance in listening comprehension exceeds reading comprehension as expected for children at that age. In spite of this mean difference a high correlation between the variables was found. In accordance with theory, the relationship between reading and listening comprehension is stronger when the influence of reading specific abilities is lower and reading material is less complex. Listening comprehension appears to be of more relevance to the prediction of reading comprehension than verbal intelligence, speed of information processing, and marks in German, even when listening comprehension is introduced as the last predictor in multiple regression analysis. It is suggested to emphasize the role of listening comprehension in the assessment and prognosis of reading disabilities.


Retrieval of action phrases: the efficacy of verb cues and noun cues. Memory for noun cues has been shown to be superior to memory for verb cues. This study investigates two factors that might influence this noun-cue superiority effect: pre-experimental associations between the cue and the target, and encoding strategies. Subjects were to study a list of noun-verb phrases. The pre-experimental associations between the two components of the phrases were either symmetric or asymmetric, and either strong or weak. One group of subjects studied the list under a standard learning instruction. The other group was required to enact the phrases. The results show that the noun-cue superiority is modulated by the variation of pre-experimental associations, that enacting considerably improves cued recall performances, and that enacting neither influences the effects of pre-experimental associations nor the efficacy of the two cuetypes.


[Constraint and inclination for reducing complexity--social cognitive aspects of moral judgment in children]. When processing information about their reality human beings systematically reduce objective complexity. This is not only true in cognitive problem solving, but also in other every-day situations, e.g., when decisions in situations of moral relevance are required. From a developmental psychological point of view the adequate handling of such situations requires, on the one hand, an age-related differentiation of social cognitions, and, on the other hand, an increasingly effective structuring and integration of information. The latter developmental process, however, bears the danger that an adequate psychosocial development is substituted by a tendency toward complexity reduction in the sense of oversimplification due to the fact that such a tendency may suggest situation-specific alternative actions which are seemingly "easier to handle". In an empirical study with 176 students from Polytechnical High Schools in (East-)Berlin the hypothesis is tested if a tendency toward oversimplification in (fictitious) situations of moral relevance is systematically related to deviant behavior at school. Results show that indeed deviant students have a stronger tendency toward oversimplifying social cognitions than non-deviant students. Furthermore, it can be shown that this result is not moderated by possible sex, age or academic performance effects. As results with regard to moral judgement in the Kohlbergian sense differ substantially in their relation to academic performance and to behavioral deviance, it is assumed that the two judgement processes differ conceptually.


Ultrastructural localization of Alzheimer amyloid beta/A4 protein precursor in the cytoplasm of neurons and senile plaque-associated astrocytes. The ultrastructural localization of amyloid beta/A4 protein precursor (APP) in the brains of control and Alzheimer's disease patients was examined immunohistochemically using antisera against the N and C termini of APP. In both control and Alzheimer brains, immunoreaction for APP was seen in the cytoplasm of most neurons, on plasma membranes, outer membrane of mitochondria, granular substance and neurofilaments. Cell bodies and foot processes of astrocytes, containing glial filaments, were also labeled. In primitive and classic type senile plaques, APP immunoreaction products were localized in the astroglial processes that surrounded the amyloid mass of the senile plaques. Swollen degenerating neurites in the senile plaques were also labeled. Amyloid fibrils were negative with APP antisera.


[Pathomechanical aspects of intra-articular calcaneus fractures. Typing, grading and surgical therapy]. The forces to produce fractures of the os calcis are combined compression and shear under a cranio-caudal impulse of 10-40 kN and a short time of stroke about 10-40 ms. The main patterns in biomechanics of calcaneal fractures are the time of stroke and the geometrical position of the foot in the moment of impact. Furthermore individual structural changes of the calcaneal cancellous bone, age, diseases as Diabetes mellitus and vascular obliterations are to be respected. Operative treatment of these fractures needs an understanding of the pathomechanism of the intracalcaneal shear-tension-forces. With plantarflexion of the foot combined with vertical forces within 40 ms to the anterior talocalcanear facette impact-fractures of the anterior part can be expected. These forces develop a posterior directed shear tension parallel to the axis of the os calcis, dividing the bone horizontally in two parts (Typ A, 44-56%), well-known as tongue-type fracture. Compression of the posterior talo-calcaneal joint leads to an impact of this structure producing the joint depression type within about 30 ms in dorsoflexion of the foot (Type B, 42%) together with sagittal shear fractures. High-energy forces are supposed to produce the so-called primary fractures of the sustentacular process in about 10 ms in a supinated position of the foot (Type C, 2-10%); these fractures represent in cases of dislocation an indication for open reduction and internal fixation. In our own experience with 45 cases in 35 patients using the lateral or/and medial approach no infection happened. Palmer's lateral approach was preferred.


[Arthrodesis of the upper ankle joint. Indications, technique, results]. From 1984 to 1990 a total of 119 arthrodesis of the upper ankle joint were performed at the Hospital of Accident Surgery of the Trade Association in Frankfurt am Main. The results of 98 patients after an arthrodesis of the upper ankle joint are documented by an x-ray control series and patient files, including the expertise on the medical status of pensioners plus a follow-up examination of 34 patients. The indications and the results are discussed on the basis of the various procedures. The results confirm the method of a compressions arthrodesis with an extension screw in case of a posttraumatic arthrosis of the upper ankle joint, while a fixateur externe should be used in case of chronical osteomyelitis, osteoporotic bones, extensive tissue swellings and after a pilon or talus fragment fracture.


[The value of digital luminescence radiography within the scope of traumatologic follow-up examinations]. At the present time we cannot unhesitatingly recommend the general use of digital luminescence radiography in traumatological follow-up examinations. Marked drawbacks of this method are, for example, sudden changes in contrast in the marginal areas of osteosynthesis material, occasional limitations in the detailed assessment of spongious structures and problems in respect of imaging geometry. By modifying the image processing parameters, increasing the image matrix and enlarging the format spectrum, however, these problems should be capable of being resolved in the future. Positive features, on the other hand, are even now the possibility of reducing the dosage to a marked degree in many traumatological follow-up examinations, especially in children and adolescents, and in case of conservatively treated fractures. In the long run we can foresee the routine use of digitalised examination methods on traumatology coupled with the possibility of storage in an image filing and communication system, although this is at present not yet feasible due to lack of requisite experience and the cost of the necessary equipment.


[An analysis of conservative therapy in 376 patients with paraplegia after injuries of the spine]. In 376 cases of paraplegia after lesions of the vertebral column which had been treated exclusively by conservative methods we were interested in changes of the neurological status, if any, during inpatient treatment, as well as in the rate of complications, the stability of the vertebral column and the immobilisation time and period of hospitalisation. 70.7% of the patients were primarily completely paralysed at admission to hospital; 6.4% of them displayed neurological improvement, compared to 49.5% of the primarily not fully paralysed patients. With decreasing height of the site of lesion of the vertebral column the rate of neurological improvement increased to a statistically significant extent. The neurological status did not deteriorate in any of the patients. Instabilities of the vertebral column were rare in our patient material, occurring in only 0.8% of the exclusively conservatively treated lesions of the thoracic and lumbar vertebral column. The average rate of complications was 13.9%, the immobilisation time approx. 10.8 weeks and the hospitalisation period on the average 25.6 weeks.


[Epidural "sulmycin implant" coverage for local prevention of infection in surgical management of open craniocerebral injuries]. In various series reported in the literature on the operative management of severe head injuries with compound depressed skull fractures and penetrating wounds of the brain, the rates of infection differ from 1 to 17%. In this paper the operative experience with 22 cases of penetrating head injuries is discussed. In conventional operative therapy, depressed skull fracture and lacerated dura were covered by "Sulmycin Implant" containing Gentamycin as a helpful bacteriological barrier. 18 patients survived, 7 patients had severe neurological defects, 5 patients had mild neurological deficits and 6 patients recovered completely. There were no signs of suppurative complications in superficial wounds or in the brain. 4 patients died due to their severe brain damage with multiple contusional lesions. Postoperative complications were as follows: one patient suffered extradural and one patient subdural rebleeding. Another patient with a frontal base skull fracture suffered a pneumatocele because the fracture was not correctly covered. The revision was done successfully using the "Sulmycin Implant". Presently, however, the intradural use of "Sulmycin Implant" is not recommended without further testing for the level of gentamycin in the cerebrospinal fluid which is released by the "Sulmycin Implant".


[Benefits and risks of surgical therapy of acute lateral fibular ligament rupture of the upper ankle joint. Results of a retrospective study]. In 60 patients with an intra-operatively confirmed first-time tear of the lateral ligaments of the ankle joint an examination carried out after a period ranging from 11.6 and 35 months post-op. showed that ligament suturing coupled with immobilisation for 6 weeks was not associated with any major or persistent impairment. The important advantage of the procedure was the possibility of accurately determining the extent of the injury, together with the chance of providing suitable and immediate correction. In 91% of the patient group, a comparison of sides revealed equal or greater stability of the surgically treated ankle joint. Even when occasional temporary, varyingly pronounced, sensory disorders are taken into account, in comparison with the possibilities of conservative therapy, we consider that these results confirm a tear of the lateral ligaments of the ankle to be a justifiable indication for surgery.


[Power stapling in trauma surgery. An improvement of trauma surgery technique?]. Power staple fixation of fracture fragments represent an enrichment of technological possibilities in adaptive osteosynthesis. We gained some experience with a variety of indications. The advantage of this method can be seen in the simple and fast way of application. Observing limited indications excellent results can be achieved.


[Decrease of postoperative morbidity in coronary surgery using the two internal mammary arteries]. The surgical risk of bilateral internal mammary artery grafting was analyzed in 100 successive patients separated chronologically into two groups. These groups were not statistically different in terms of age, severity of angina, and extent of coronary artery disease. The number of grafts per patient and the time of aortic cross clamping were not statistically different in the two groups. The postoperative mortality was 1% in the 100 patients. The incidence of perioperative myocardial infarction was not statistically different in the two groups. No mediastinal suppuration was observed. The mean postoperative hemorrhage was 633 +/- 558 ml in the first 50 patients and 560 +/- 410 ml for the last 50 patients (p < 0.05). The percentage of patients receiving no homologous blood transfusion was 64% in the first 50 patients and 94% in the last 50 patients. The percentage of phrenic palsy was 36% in the first 50 patients and 6% in the last 50 patients (p < 0.05). With surgical experience, the risk of coronary bypass with bilateral internal mammary artery was lowered and very similar to the surgical risk of conventional aorto-coronary bypass with saphenous veins or one mammary artery.


[Place of the right gastro-epiploic artery in coronary revascularization by exclusive arterial grafts]. From March 1990 to July 1991, 35 patients underwent coronary artery bypass grafts using the right gastro-epiploic artery (GEA). Twenty-nine patients had exclusively arterial grafts using a combination of GEA and internal mammary artery (IMA) in situ. The selection criteria for this group of 29 patients included a life expectancy exceeding ten years to avoid the need for reoperation due to deterioration of the grafts. This group consisted of 27 men and two women under the age of 70 years (mean age: 58 years, range: 36 to 70), 11 patients (38%) were under the age of 50 years and 15 (52%) were under the age of 60 years. Cardiac status was relatively well preserved. The mean ejection fraction was 58% (range: 25-70%). Fourteen patients (48%) had had a preoperative myocardial infarction. Fifty-five p. cent were smokers, 41% suffered from HT and 31% had a dyslipidaemia. Six patients (20%) had respiratory failure, 6 others (20%) were severely overweight and 2 patients were diabetic. According to the NYHA classification, 14 patients (48%) were stage IV, 9 patients (31%) were stage III and 6 patients (20%) were stage II. The mean number of bypass grafts per patient was 2.8 and 8 sequential bypass grafts (27%) were performed. The GEA was used in 29 cases, the left IMA was used in 28 cases, the right IMA was used in 13 cases and the epigastric artery was used as a free graft in 3 cases. Associated lesions included a resected left ventricular aneurysm. No associated valve procedures were performed.(ABSTRACT TRUNCATED AT 250 WORDS)


[Use of the internal mammary artery as a free graft with reimplantation of the proximal end onto the ascending aorta. Apropos of 39 cases]. From January 1987 to January 1991, 104 patients received bilateral internal mammary artery grafts and 39 of them had coronary bypass with a free graft implanted on the ascending aorta. There were 35 men, with a mean age of 57.35 years (range 41 to 70 years). 87% of them had stable angina, and 23 had preoperative myocardial infarction. The left ventricular function was good in 77 per cent of cases. 23 patients had three vessel disease (61.5%), 13 two vessel diseases (30.7%), 2 one vessel disease (5.12%) and one a left main coronary stenosis. Left internal mammary artery was used in two patients on the left descending artery and the right internal mammary artery was used in 37 patients: 15 on the circumflex, 15 on the right coronary, 4 on the LDA and 3 on the diagonal artery. Five patients had one graft, 32 two grafts and one three grafts (bilateral mammary and saphenous vein). Hospital mortality was 2.56% (1 patient) and there were 2 late deaths (5.12%). There were 5 perioperative myocardial infractions (12.8%) and no sternal infections. The mean follow up is 21 months (range 3 to 46 months). At follow-up, 34 patients (87.2%) were asymptomatic, and there were no myocardial infarctions. Postoperative angiography in 8 patients (mean postoperative time 2.5 months) showed that all the grafts were patent. This analysis demonstrates that free IMA graft has a low operative risk and provides excellent long term functional improvement and survival.


[Beta-blockaders and atheroma regression: a necessary evaluation?]. Beta-blockers have been shown to have a beneficial effect especially regarding secondary prevention in coronary patients. The reduction in global mortality is most noticeable with respect to sudden death, which suggests an antiarrhythmic effect, but other non-lethal ischaemic events are also less frequent. The explanation of this observation is certainly multifactorial: some results point to a potential action on the development of atherosclerotic lesions. This justifies experimental and clinical studies of this hypothesis with this pharmacological group of drugs.


[Communication between stem cells and the hematopoietic microenvironment. Experimental data and models of interaction]. The aim of this review is to analyze the different ways by which stem cells and microenvironmental cells may interact. Stem cells are defined as immature cells that ensure the continuous renewal of blood cells. This small set of marrow cells comprises different kinds of cells, differing by their degree of maturity, their commitment, self-renewal ability and repopulating capacity. Microenvironmental cells are fixed marrow cells involved in stem cell survival, proliferation and differentiation. In vivo studies on the distribution within spleen or marrow, of stem cells injected to lethally irradiated mice, have suggested that cells of the microenvironment play a significant role in stem cell proliferation and differentiation. This role has been demonstrated using an in vitro model, i.e. the long-term marrow cultures as described in 1976 by M. Dexter. Analysis of stem cell maintenance in this culture system has made it possible to define the different means by which stromal cells and macrophages (the microenvironmental cells) may control stem cell behavior. Different molecules play a critical role: cytokines (growth factors and inhibitors), adhesion molecules (cell adhesion molecules and molecules belonging to the extracellular matrix) and eventually small peptides. It appears nowadays possible to materially represent the hemopoietic niche, whose existence was postulated by R. Schofield 10 years ago for theoretical reasons related to the the physiology of stem cells.


[Long-term tolerability of formoterol in chronic obstructive bronchopathies]. Formoterol aerosol, a long-acting new beta 2-mimetic was administered over a year at a dose of 12 micrograms twice daily, to 62 chronic obstructive bronchitics of mean age 66 +/- 6 years and of whom the basal VEMS was at 12,801 +/- 0.59. Clinical tolerance of the product was good with undesirable effects in 13 patients, the most frequent being shaking. No untoward effect was seen on systolic or diastolic arterial pressure, or the heart rate over successive visits at 1, 3, 6, 9 months and one year. Electrocardiographic surveillance found in only four patients electrical abnormalities that may be due to Formoterol, these were patients without previous cardiac problems but of advanced mean age. Functionally, a significant improvement of basal VEMS was noticed from the 6th month. The VEMS improved significantly after administration of 12 micrograms on successive visits, without tachyphylactic signs. Well tolerated, with functional benefits, Formoterol is a promising product amongst the long-acting beta 2-mimetics. Its usefulness and limitations in the basic treatment of these chronic bronchopathies remains to be defined.


Antinociceptive action of dopamine agonists in the nucleus raphe magnus of rats is mediated by D2 receptors. We have shown previously that the dopamine agonist apomorphine is antinociceptive when injected into the nucleus raphe magnus of rats, presumably via stimulation of descending antinociceptive pathways. We have now extended the investigation to receptor-specific agonists. We measured nociception in conscious Sprague-Dawley rats, using the latency of the first flexor response following tail immersion in water at 49 degrees C, before and after injection of agonists into the nucleus raphe magnus through chronically implanted cannulae. The D2 agonist PPHT HCl produced an increase in latency, i.e. hypoalgesia, for 30 min after injection of doses of 10 and 20 nmol. The lowest dose of the D1 agonist SKF 38393 produced no change in latency, but a bimodal response was found at the higher two doses (20 and 200 nmol), with hypoalgesia at 15 min, followed by a sustained hyperalgesia. The dopamine autoreceptor agonist R (+)-3PPP produced a significant hypoalgesia at 10 and 20 nmol 15 min after injection, with no subsequent hyperalgesia. Our results are consistent with the hypothesis that the antinociceptive action of dopamine in the rat nucleus raphe magnus is mediated by the D2 receptor.


Polymorphism of the Pa gene.

Polymorphism of the Pa gene. This study was undertaken to identify the number of alleles of the Pa gene at the DNA level and to correlate the presence of the different alleles with the ability of a strain to elicit an anti-Pa antibody response when mated with a WF female. The Pa gene is present in both Pa+ and Pa- strains of rats, but it has unique restriction fragment length polymorphisms (RFLP) in the two types of strains: 1.7 kb in Pa- and 1.8 kb in Pa+XbaI digests using a probe derived from the Pa gene. Examination of DNA from a variety of strains using different enzymes showed that there were characteristic RFLP patterns for Pa+ and Pa- strains. Strains of the b haplotype, however, had an intermediate RFLP pattern, and all of these strains had a relatively low level of reactivity with anti-Pa antibody. Thus, there are three alleles of the Pa gene based on their level of expression: Paa, high; Pab, low; and Pa-, none.


Prognostic significance of proliferating cell nuclear antigen-positive growth fraction in gastric adenomas. The proliferative activity of gastric adenomas from 18 patients (42 endoscopic procedures) was compared with follow-up results. These cases were gastric adenomas proven by follow-up with repeated endoscopic procedures for more than 2 years, or were confirmed as gastric adenocarcinoma thereafter by histopathologic examination. Among the eighteen cases, nine showed carcinoma in the subsequent biopsies (group 1) and the remaining nine did not result in carcinoma (group 2). The proliferating cell nuclear antigen (PCNA) positivity rates of the two groups were significantly different (P < 0.01). The average PCNA positivity in group 1 was 33.1%, while it was 10.0% in group 2. The risk of developing carcinoma increased as the PCNA positivity increased: 0% in the low PCNA positivity group, 41% in the mid-positivity group and 89% in the high positivity group. We concluded that growth fraction could be taken into account as one of the most important prognostic factors for gastric adenoma, and accordingly repeated endoscopic biopsies with close follow-up should be carried out especially in the high PCNA positivity group.


Compartmentalization of monoaminergic synaptic vesicles in the storage and release of neurotransmitter. Monoaminergic nerves are characterized by the presence of a population of small synaptic vesicles (40-60 nm in diameter) containing a few large vesicles (80-90 nm in diameter). Thus, although both types of vesicles contain monoamines, the small vesicles must be considered as the organoid responsible for the storage and release of the neurotransmitter, whereas the large ones possibly are involved in the modulation of the process. The small vesicles are electron-lucent or have an osmiophilic electron-dense core that is always linked to the vesicle membrane. Considering morphological and histochemical evidence under different experimental conditions, we proposed the existence of two compartments in the small vesicles: the core and the matrix, corresponding respectively to the electron-dense core and the electron-lucent space between the core and the vesicle membrane in osmium tetroxide fixations. The sizes of both compartments are inversely related, i.e., the smaller the core, the larger the matrix and vice versa. The core even disappears, giving way to a small electron-lucent vesicle made exclusively by the matrix. Thus, the matrix is a constant component of the vesicle, whereas the core is a transient one. Each compartment has a different pool of amine: a loosely bound, easily releasable pool in the matrix and a tightly bound, more resistant pool in the core. These two pools subserve, respectively, a tonic or phasic release of the neurotransmitter, correlated with a tonic or phasic stimulation of the receptor. The core may be considered as a storage or reserve pool. Experimental evidence from our laboratory supports the concept that different mechanisms are operative in both compartments in the release of the neurotransmitter. For instance, a Ca2(+)-independent release would be primarily concerned with the neurotransmitter contained in the matrix, and a Ca2(+)-dependent efflux would be primarily related with the neurotransmitter stored in the core. However, it still must be established that a simple relationship exists between each kind of stimulus and each vesicle compartment, rather than both compartments being integrated in a dynamic functional unit.


In search of synaptosomal Na+,K(+)-ATPase regulators. The arrival of the nerve impulse to the nerve endings leads to a series of events involving the entry of sodium and the exit of potassium. Restoration of ionic equilibria of sodium and potassium through the membrane is carried out by the sodium/potassium pump, that is the enzyme Na+,K(+)-ATPase. This is a particle-bound enzyme that concentrates in the nerve ending or synaptosomal membranes. The activity of Na+,K(+)-ATPase is essential for the maintenance of numerous reactions, as demonstrated in the isolated synaptosomes. This lends interest to the knowledge of the possible regulatory mechanisms of Na+,K(+)-ATPase activity in the synaptic region. The aim of this review is to summarize the results obtained in the author's laboratory, that refer to the effect of neurotransmitters and endogenous substances on Na+,K(+)-ATPase activity. Mention is also made of results in the field obtained in other laboratories. Evidence showing that brain Na+,K(+)-ATPase activity may be modified by certain neurotransmitters and insulin have been presented. The type of change produced by noradrenaline, dopamine, and serotonin on synaptosomal membrane Na+,K(+)-ATPase was found to depend on the presence or absence of a soluble brain fraction. The soluble brain fraction itself was able to stimulate or inhibit the enzyme, an effect that was dependent in turn on the time elapsed between preparation and use of the fraction. The filtration of soluble brain fraction through Sephadex G-50 allowed the separation of two active subfractions: peaks I and II. Peak I increased Na+,K(+)- and Mg(2+)-ATPases, and peak II inhibited Na+,K(+)-ATPase. Other membrane enzymes such as acetylcholinesterase and 5'-nucleotidase were unchanged by peaks I or II. In normotensive anesthetized rats, water and sodium excretion were not modified by peak I but were increased by peak II, thus resembling ouabain effects. 3H-ouabain binding was unchanged by peak I but decreased by peak II in some areas of the CNS assayed by quantitative autoradiography and in synaptosomal membranes assayed by a filtration technique. The effects of peak I and II on Na+,K(+)-ATPase were reversed by catecholamines. The extent of Na+,K(+)-ATPase inhibition by peak II was dependent on K+ concentration, thus suggesting an interference with the K+ site of the enzyme. Peak II was able to induce the release of neurotransmitter stored in the synaptic vesicles in a way similar to ouabain. Taking into account that peak II inhibits only Na+,N(+)-ATPase, increases diuresis and natriuresis, blocks high affinity 3H-ouabain binding, and induces neurotransmitter release, it is suggested that it contains an ouabain-like substance.


Insulin insensitivity in nonobese, nondiabetic essential hypertension and its improvement by an alpha 1-blocker (bunazosin). To investigate insulin insensitivity and its reversibility, we performed an insulin sensitivity test using the steady state plasma glucose (SSPG) method in 10 lean hypertensive subjects with normal glucose tolerance before and after treatment with alpha 1-blocker bunazosin, and 14 age body mass index-adjusted healthy control subjects. Steady state plasma glucose was significantly higher in the hypertensive subjects compared with the control group (182 +/- 10 mg/dL v 104 +/- 7, P < .01, mean +/- standard error of the mean (SEM). Steady state plasma glucose significantly decreased to 136 +/- 12 mg/dL (P < .01) after the treatment with alpha 1-blocker bunazosin, with a decrease of blood pressure. Hypertensive subjects had shown an increased area under the curve of glucose and insulin during the oral glucose tolerance test compared with normal controls. The glucose area decreased significantly, but the insulin area did not change after the treatment. There was no difference in plasma epinephrine, norepinephrine, and fractional excretion of Na between normal and hypertensive subjects both before and after treatment with bunazosin at basal and during insulin sensitivity tests (2 h). Serum total cholesterol level decreased and HDL cholesterol increased significantly after treatment with bunazosin. A significant correlation was observed between SSPG and blood pressure, but not between insulin level and blood pressure. The results indicate that insulin sensitivity is better related than hyperinsulinemia to hypertension and that this insensitivity is partially reversible by alpha 1-blocker, bunazosin.


The mechanism of perturbation in monoamine metabolism by L-dopa therapy: in vivo and in vitro studies. In the cerebrospinal fluid of the patients with Parkinson's disease treated with L-DOPA, L-3-O-methyldopa was the major metabolite of administered L-DOPA. Using a dopaminergic cell model, clonal rat phenochromocytoma PC 12h cells, and by microdialysis of the rat striatum it was proved that L-3-O-methyldopa was taken up into monoamine neurons by transport system specific for aromatic L-amino acids and inhibited transport of L-DOPA and other amino acids competitively. L-3-O-Methyldopa depleted allosteric regulation of the biopterin cofactor on activity of tyrosine hydroxylase, the rate-limiting enzyme of catecholamine synthesis. Depletion of the allostery may perturb the buffer action of endogenous L-DOPA synthesis that stabilizes dopamine level in the brain. By these mechanisms L-3-O-methyldopa may reduce clinical effectiveness of administered L-DOPA and be involved in wearing-off phenomenon. L-DOPA inhibited the activity of tryptophan hydroxylase and thus serotonin synthesis, which may be related to psychiatric side-effects in the patients under L-DOPA therapy.


Torsion of a malignant undescended testis mimicking appendicitis. Testicular maldescent is known to be associated with later development of malignancy. The maldescended testis is prone to other complications--in particular, torsion. We report an unusual coincidence of both malignancy and torsion of an intra-abdominal testis which closely simulated a ruptured appendix abscess. This case demonstrates that an intra-abdominal testis can develop acute life-threatening complications which should be considered in any patient with acute abdominal symptoms who has an 'absent' testis.


Differential locomotor interactions between dopamine D1/D2 receptor agonists and the NMDA antagonist dizocilpine in monoamine-depleted mice. Previous work in our laboratory has shown that the non-competitive N-methyl-D-aspartate antagonist dizocilipine (MK-801) interacts synergistically with the mixed dopamine (DA) receptor agonist apomorphine and the DA D 1 agonist SKF 38393 to promote locomotion in monoamine-depleted mice. The purpose of the present study was to compare the roles of DA D 1 and DA D 2 receptors in this interaction. To that end, dizocilpine was given in combination with either the DA D 1 receptor agonist SKF 38393 or the selective DA D 2 receptor agonist quinpirole or the preferential DA D 2 agonist bromocriptine. In general, the locomotor stimulatory effects produced by SKF 38393 were potentiated by dizocilpine, whereas the locomotor stimulation produced by quinpirole and bromocriptine was counteracted. However, baseline activity, which partly depends on how much time is allowed to elapse between administration of the DA agonist and commencement of locomotor recording, and partly on the dose of the DA agonist, seems to be an important factor that determines whether dizocilpine will have a weakening or a potentiating effect. Interestingly, the competitive NMDA antagonist D-CPPene displayed a different pattern of interaction with SKF 38393 and quinpirole in that synergistic effects were observed with both DA agonists, most conspicuously so with the DA D 2 receptor agonist. The results are interpreted in the light of present knowledge of basal ganglia neuroanatomy; they are discussed in relation to the "direct" and "indirect" pathways from the striatum to the thalamus, proposed to form part of positive and negative cortico-striato-thalamo-cortical loops, respectively, as well as to the presumed presynaptic D 2 receptors on corticostriatal glutamatergic neurons.


A co-stimulatory role for CD28 in the activation of CD4+ T lymphocytes by staphylococcal enterotoxin B. In this study we investigated the differential effect of the co-stimulatory receptor ligand molecules CD2/LFA-3, LFA-1/ICAM-1, and CD28/B7 on microbial superantigen mediated activation of CD4+ T cells. Highly purified CD4+ T cells, depleted of antigen presenting cells (APCs), do not proliferate in response to the superantigen, staphylococcal enterotoxin B (SEB). However, CD4+ T cells do respond to SEB in the presence of the LFA-3, ICAM-1, and B7 positive erythroleukemic cell line K562, murine L cells, human B7 transfected L cells or CD28 mAb. The K562 plus SEB induced response can be inhibited by combinations of mAbs to CD2 and LFA-1, and to LFA-3, ICAM-1, and B7. Addition of CD28 mAb to the CD2 and LFA-1 inhibited cultures could restore the response. Furthermore, soluble CD28 mAb alone is able to synergize with SEB to induce a proliferative CD4+ T cell response. CD4+ T cells depleted of APCs could also be activated by a pool of four mAbs directed to the V beta 5, V beta 6, V beta 8, and V beta 12 region of the TCR when a co-stimulatory signal was provided by the CD28 mAb, while the V beta mAbs alone or in combination are unable to activate CD4+ T cells in the absence of APCs. In contrast, addition of soluble mAbs to CD2 and LFA-1 molecules failed to co-stimulate SEB activated CD4+ T lymphocytes. The kinetics of the different modes of activation are distinct. SEB induced proliferation is most efficient in the presence of autologous APCs with maximal proliferation at a log4 lower SEB concentration than when CD28 mAbs were used. SEB plus K562 activation peaks on day 7, while SEB plus CD28 mAb induced proliferative responses do not peak until day 9. Thus, superantigen mediated activation of CD4+ T cells requires co-stimulatory signals, among which CD28 has distinct and unique effects.


Life and death of a superantigen-reactive human CD4+ T cell clone: staphylococcal enterotoxins induce death by apoptosis but simultaneously trigger a proliferative response in the presence of HLA-DR+ antigen-presenting cells. We report that a human CD4+ T cell clone with specificity for staphylococcal enterotoxin (SE) superantigens A, D, and E can respond to SEs in two seemingly opposite ways. In the absence of antigen presenting cells (APC), SEA, D, and E (but not SEB or C1) strongly inhibited in a dose-dependent manner the responsiveness of clone D894/25 to exogenous IL-2. Growth inhibition was due to SE-induced programmed cell death (apoptosis) as shown by propidium iodide staining and the appearance of the characteristic ladder pattern of DNA fragmentation. Apoptotic cell death was accompanied by significant cell lysis after 4 and 8 h as measured in a 51Cr release assay. In contrast (but as expected), a proliferative response of clone D894/25 was triggered by SEA, D, and E in the absence of exogenous IL-2 but presence of HLA class II-positive lymphoblastoid cell line (LCL) as APC. Moreover, the addition of LCL feeder cells partially prevented the suppression of IL-2 responsiveness by SEs. Surprisingly, however, the latter two culture conditions (i.e. presence of LCL feeder cells with or without exogenous IL-2) were associated with similar levels of induced cell death as in the absence of LCL. At the clonal level, these data demonstrate that SE superantigens induce programmed cell death in a fraction (40-50%) of responsive mature T cells, irrespective of the presence or absence of MHC class II-positive APC. We conclude that the proliferative response of clone D894/25 which is triggered by SEs in the presence of APC and absence of IL-2 must originate from the fraction (50-60%) of clone T cells surviving SE-induced cell death.


Abnormal distribution of IL-6 receptor in aged MRL/lpr mice: elevated expression on B cells and absence on CD4+ cells. A mAb against murine IL-6 receptor (IL-6R), KMH7, was obtained by immunization of hamster with recombinant soluble murine IL-6R. Flow cytometry analysis of IL-6R distribution on lymphocytes in BALB/c showed that IL-6R was expressed on peripheral lymph node (LN) T cells of either CD4+ or CD8+ phenotype, and Peyer's patch IgA+ B cells, but not on splenic B cells and thymocytes. A similar distribution was observed in 5 week old MRL/lpr and 16-week-old MRL/n mice. In contrast, in 16 week old MRL/lpr mice of both sexes, IL-6R was expressed on splenic IgM+ cells. Peripheral LN CD4+ T cells in 16 week old female MRL/lpr mice did not express IL-6R. Thymocytes in any population with a phenotype of CD4+ or CD8+, double negative, and double positive were not stained with KMH7 in both BALB/c and MRL/lpr mice. In both strains, IL-6R was induced in CD4+ or CD8+ thymocytes after 2 days of culture, suggesting that CD4+ thymocytes in MRL/lpr have a potential to express IL-6R. Our results suggest that overexpression of IL-6R on B cells and absence of IL-6R on peripheral CD4+ cells are concurrent with, or may contribute to, B cell hyperreactivity and T cell abnormality in this strain.


Alpha 2-adrenoceptor control of ion and water transport in the newt renal distal tubule. To study the nature of adrenergic stimulation of ions and water reabsorption in the newt renal distal tubule, stationary microperfusion of the nephron and electron probe analysis were used. After application of norepinephrine (NE 10(-6) M) to the tubule surface, the fractional reabsorption of fluid increased from 15.0 +/- 3.1 to 41.30 +/- 10.4% (n = 7, p < 0.01), of Na+ from 69.30 +/- 6.6 to 79.10 +/- 7.5% (p < 0.05), Cl- from 63.30 +/- 7.6 to 72.40 +/- 7.9% (p < 0.05). Instead of secretion (control), there was reabsorption of K+. Fractional reabsorption of Ca2+ decreased from 51.00 +/- 6.0 to 43.00 +/- 7.0% (p < 0.05). The nonspecific alpha-adrenergic antagonist dibenamine 10(-6) M completely inhibited the effect of NE while, under the action of propranolol (2 x 10(-6) M) NE increased ion and water reabsorption significantly. When applied alone, or with NE, the specific alpha 2-adrenoblocker idazoxan, 2 x 10(-6) M, did not interfere with reabsorption in the distal tubule. At the same time, under the action of alpha 1-adrenoblocker prazosin 2 x 10(-6) M NE, increased the fractional reabsorption of fluid from 24.10 +/- 3.4 to 44.40 +/- 4.0% (n = 6, p < 0.001). These results serve as evidence that there exist specific alpha 2-adrenoceptors in the newt distal tubule the stimulation of which increases membrane permeability of the distal tubule to water, Na+, K+, Cl-, but not to Ca2+.


Comparison of the potency of five potential beta-adrenoceptor blocking drugs and eight calcium channel blockers to inhibit platelet aggregation and to perturb liposomal membranes prepared from platelet lipids. Five potential beta-adrenoceptor blocking (BAB) compounds, alkylesters of 4-[(2-hydroxy-3-alkylamino)propoxy] phenylcarbamic acid, and eight calcium channel blockers (CB), i.e. nifedipine, nimodipine, niludipine, nitrendipine, verapamil, gallopamil, mepamil and diltiazem, were compared as to their inhibitory effect on thrombin induced aggregation of washed rat platelets and their effect on dynamics/disorder of liposomal membranes prepared from platelet lipids, studied by EPR spectroscopy of a lipid spin probe. The anti-aggregatory potency of the BAB and CB drugs was effective within the concentration range of 0.01-1 mmol/l. The antiaggregatory potency of BAB increased in the order BL-143 < BL-243 < BL-343 < BL-443 < BL-543 and among the CB, nifedipine and diltiazem were least potent, whereas nitrendipine and mepamil were the most potent drugs. The potency of the other CB tested was intermediate. The BAB drugs increased the dynamics/disorder of the liposomes in the same order as they inhibited platelet aggregation, whereas there was no relationship between antiaggregatory effect of CB and their influence on dynamics/disorder of the liposomes. Nifedipine, nimodipine, niludipine and nitrendipine had a minor perturbation effect on the liposomes, whereas verapamil, mepamil, gallopamil and diltiazem pronouncedly increased the dynamics/disorder of the hydrophobic part of the liposomes. The results indicate that the anti-aggregatory activity of BAB drugs may be mediated, at least partially, through their perturbation effect on the lipid part of biological membranes.


Efficacy of stellate ganglion block: a clinical study with bupivacaine. When administering stellate ganglion blocks (e.g., to pain patients), it may be essential to know whether the sympathetic block is complete. The aim of the present study was to study the efficacy of stellate ganglion blocks using different concentrations and volumes of local anesthetic and different sites of injection. Fifty-four stellate ganglion blocks (cervicothoracic sympathetic blocks) were performed for relief of chronic pain in 30 patients, all with a pre-block palmar skin temperature 32 degrees C or lower. Bupivacaine in random combinations of concentration (high, 5 mg/ml; low, 2.5 mg/ml), volume (high, 15-20 ml; low, 5-10 ml), and site of injection (C6 or C7) was used. The efficacy of these combinations was assessed by registering the following changes in effector organ activity: (1) observed signs (e.g., Horner's syndrome: miosis, ptosis, enophthalmos, and reddening of the sclera) and (2) objective measurements of changes in skin temperature, skin blood flow (laser Doppler flowmetry), skin resistance response, and in skin resistance level. Only 15 of 54 blocks met four of the five criteria for an effective block: a Horner's syndrome in combination with an increased skin temperature (to > or = 34 degrees C), increased skin blood flow ( > or = 50%), and completely abolished skin resistance response on both the radial and the ulnar sides of the blocked hand. Only six of those 54 met all five criteria: they also had an increase ( > or = 13%) in skin resistance level on the radial and ulnar sides. Injection toward C7 instead of injection toward C6, and high concentration instead of low, seemed to be more advantageous, whereas volume seemed to be of less importance. A relationship between pre-block skin temperature and the rise in temperature during the block was found. It was difficult to achieve a block that met all five established criteria. When assessing the efficacy of a stellate ganglion block, it is essential to evaluate the effects on vasoconstrictor and sudomotor fibers.


Disposition of human drug preparations in the horse. II. Orally administered fencamfamine. A gas chromatographic method to measure urinary levels of the central nervous system stimulant fencamfamine and some of its metabolites is described. When 100 mg fencamfamine was given orally to four horses the parent drug could not be detected in the urine. After enzymatic hydrolysis of the urine the major human metabolite, N-desethylated fencamfamine, only accounted for 1% of the dose in 12 h. The major equine metabolites were conjugated parahydroxylated compounds representing 18% of the dose. With regard to horse doping control and analysis, the injudicious use of human doping routine methods for the detection of fencamfamine in equine urine could lead to false negative results.