Intestinal brush-border-associated enzymes: co-ordinated expression in colorectal cancer. The brush border of normal small-intestine epithelial cells is rich in enzymes that are involved in the digestive process. Such molecules can be used as markers to analyze cell lineages and differentiation properties of colorectal cancers. Monoclonal antibodies detecting dipeptidyl peptidase-IV, aminopeptidase N, endopeptidase F, sucrase-isomaltase, alkaline phosphatase, maltase-glucoamylase and lactase have been used to analyze the phenotype of colorectal cancers, adjacent mucosa and histologically normal distant mucosa. The avidin-biotin peroxidase complex method was used. Expression of dipeptidyl peptidase-IV, aminopeptidase N, sucrase-isomaltase and alkaline phosphatase was common in non-neoplastic mucosa adjacent to, and distant from, the tumor; in contrast, endopeptidase F, maltase-glucoamylase and lactase were rarely expressed in normal distant mucosa and more frequently expressed in mucosa adjacent to the tumor. Dipeptidyl peptidase-IV, aminopeptidase N, endopeptidase F, sucrase-isomaltase and alkaline phosphatase were frequently expressed in colorectal cancers, whereas maltase-glucoamylase and lactase were rarely expressed. Two general patterns of antibody reactivity were observed: diffuse cytoplasmic and apical; apical reactivity was generally associated with more differentiated tumors. A logistic predictive regression model indicated that enzyme expression in colorectal cancers followed a coordinate pattern, but was unrelated to the location of the tumor, Dukes stage or differentiation grade. In conclusion, expression of brush-border-associated enzymes occurs frequently in colorectal cancers and is regulated in a co-ordinated manner. These markers can be used for the phenotypic sub-classification of colorectal cancers.


Chromogranin-A expression in gastric and colon cancer tissues. We studied the expression of chromogranin A (CgA) in human gastric (n = 17) and colorectal (n = 18) adenocarcinomas by nucleic acid hybridization and immunohistochemical analyses using a specific monoclonal antibody (MAb) to human chromogranin A (CgA). Some corresponding adjacent non-malignant mucosal tissues were also examined. (1) Northern blotting: of 3 normal gastric mucosas examined, 2 (67%) had an easily detected signal for expression of CgA. Only one of 14 gastric carcinomas (7%) and one of 18 colorectal carcinomas (6%) had easily detected RNA signals. (2) Immunohistochemical staining: all non-malignant samples of gastric and colonic mucosa contained CgA-positive neuroendocrine (NE) cells. Two of 17 (12%) gastric adenocarcinomas, and 3 of 18 (17%) of colorectal adenocarcinomas contained CgA-positive tumor cells. Interestingly, the positive cases detected by immunohistochemistry included both cases detected by Northern blotting. Of the 5 cases detected by immunohistochemistry, 2 gastric cancers and 1 rectal carcinoma contained many diffusely scattered positive cells, occurring singly or in small clusters, while 2 colorectal carcinomas contained only occasional single CgA-positive tumor cells. In one of the positive gastric cases, a well-differentiated adenocarcinoma arising in a tubular adenoma, both the adenomatous and the carcinomatous elements contained positively staining cells. Our specific assays for CgA indicate that (1) a NE cell component, either diffusely scattered or occasional, occurs in about 15% of gastric and colorectal tumors; (2) there is no correlation between the presence of NE cells and degree of tumor differentiation; and (3) because only a minority of the tumor cells in positive cases stain for CgA, immunohistochemistry is a more sensitive method than Northern blotting.


Characterization of adenovirus genome type 7h: analysis of its relationship to other members of serotype 7. Ad7h is a newly identified genome type associated with severe lower acute respiratory infections and has so far been isolated only in South America. To obtain a clue to its possible origin, the degree of restriction enzyme site homology between adenovirus genome type 7h and those representative of the three described genomic clusters (GC) for serotype 7 was studied by analysis of pairwise comigrating DNA restriction fragments (PCRF) after digestion with BamHI, BglI, BglII, BstEII, EcoRI, HindIII, HpaI, SalI, SmaI, XbaI, and XhoI. The most closely related genome types, Ad7b, Ad7d, and Ad7g, displayed 85.7, 83.8, and 82.8% comigrating fragments, respectively. Ad7p (GC1) was clearly distant with only 68.6% PCRF. No remarkable close genetic relationships (%PCRF greater than 90) were observed with any of the genome types grouped within GC3 or with Ad7g (the only member of GC2), so since Ad7h seems to be related to both members of GC2 and GC3, it could equally be considered to represent a new cluster or to end up grouped in either GC2 or GC3, depending on the results of further analysis.


A second serogroup of Legionella erythra serologically indistinguishable from Legionella rubrilucens. Twenty-two red-autofluorescent Legionella strains were identified serologically as either Legionella rubrilucens or L. erythra. A rRNA probe was used for restriction fragment length polymorphism (RFLP) analysis of the strains and the patterns generated were used as an additional method of identifying the strains to species level. In two instances strains which were identified as L. rubrilucens by serology appeared to belong to the species L. erythra by RFLP analysis. This apparent contradiction was resolved by measurements of DNA/DNA homology which confirmed the existence of a second serogroup of L. erythra serologically indistinguishable from L. rubrilucens.


Nerve stimulation decreases malonyl-CoA in skeletal muscle. This study was designed to determine the effect of in situ electrical stimulation of the sciatic nerve on malonyl-CoA, an inhibitor of carnitine palmitoyl transferase, in the gastrocnemius/plantaris muscle group of rats. The left sciatic nerve was stimulated at a frequency of 5 Hz with 100-ms trains of impulses (50 Hz) for 1, 3, or 5 min. At the end of stimulation, the left and right (nonstimulated) gastrocnemius/plantaris muscle groups were clamp-frozen and later analyzed for malonyl-CoA and other metabolites. No change was observed in the noncontracting contralateral muscles in malonyl-CoA, ATP, creatine phosphate (CP), or citrate. In the stimulated muscles, malonyl-CoA decreased from 1.7 +/- 0.1 to 1.0 +/- 0.1 nmol/g (P less than 0.05), and CP decreased from 15.8 +/- 0.9 to 12.2 +/- 1.0 mumol/g (P less than 0.05) after 3 min of stimulation. After 5 min of stimulation, malonyl-CoA was 1.0 +/- 0.1 nmol/g and CP was 10.3 +/- 1.3 mumol/g. When muscles were stimulated for 5 min with single impulses (5 Hz), malonyl-CoA was decreased from 1.8 +/- 0.3 to 1.0 +/- 0.1 nmol/g, with no change in CP, ATP, or adenosine 3',5'-cyclic monophosphate. Thus a decline in malonyl-CoA can be induced by muscle contraction independently of humoral influence.


Phosphorylation of ryanodine receptors in rat myocytes during beta-adrenergic stimulation. We studied beta-adrenergic agonist-stimulated phosphorylation of the ryanodine receptor in rat cardiac myocytes. The ryanodine receptor solubilized from myocytes and immunoprecipitated by a monoclonal antibody against canine cardiac ryanodine receptor was phosphorylated by the catalytic subunit of cAMP-dependent protein kinase (PKA). Incubation of saponin-permeabilized myocytes with [gamma-32P]ATP also induced ryanodine receptor phosphorylation, which was enhanced significantly in the presence of isoproterenol. This stimulating action of isoproterenol was suppressed by the beta-adrenergic antagonist, propranolol. On the other hand, exogenously added cAMP caused a much larger stimulation of phosphorylation of the ryanodine receptor in permeabilized myocytes. The beta-agonist-induced phosphorylation of the ryanodine receptor was also observed in intact myocytes from the newborn rat heart. These results suggest that the ryanodine receptor is phosphorylated by PKA during beta-adrenergic stimulation of cardiac myocytes.


Multidrug transport in human autoimmune T line cells and peripheral blood lymphocytes. We studied multidrug transport in human autoimmune T line cells and peripheral blood leukocytes, because multidrug transport is pleiotropically limiting the intracellular accumulation of immunosuppressive and chemotherapeutic agents. We observed that a subpopulation of peripheral blood leukocytes containing CD4+, CD8+ and Ig+ lymphocytes expressed a multidrug transport system. Lymphocytic multidrug transport was seen with all peripheral blood samples analyzed, but showed considerable variations between individuals. In further studies with human lymphocytic cell lines multidrug transport was seen with 18/23 human CD4+ T cell lines. Interestingly, expression of multidrug transport was independent of T cell activation. No significant transport was observed with EBV-transformed human B lymphocytes, rat T line cells or rat, mouse, or guinea pig leukocytes.


Increased oncogenic potential of ErbB is associated with the loss of a COOH-terminal domain serine phosphorylation site. The erbB oncogene encodes an altered form of the epidermal growth factor (EGF) receptor that lacks the extracellular ligand binding domain. This oncogene is exclusively leukemogenic. However, an increase in oncogenic potential and a broadening of the tissue specificity of tumor formation occurs after retroviral transduction of erbB. The increased oncogenic potential correlates with structural alterations within the erbB gene. One common event is the deletion of a serine phosphorylation site located within the COOH-terminal domain. This site of phosphorylation has been demonstrated to be required for EGF-induced desensitization of signaling by the EGF receptor (Countaway, J. L., Nairn, A. C., and Davis, R.J. (1992) J. Biol. Chem. 267, 1129-1140). Here we show that the mutation of erbB at this negative regulatory serine phosphorylation site causes fibroblast transformation in vitro and is associated with an increased oncogenic potential in vivo.


Heterodimerization of c-erbB2 with different epidermal growth factor receptor mutants elicits stimulatory or inhibitory responses. Ligand-induced dimerization of growth factor receptors is crucial for stimulation of their intrinsic protein tyrosine kinase activity promoting receptor autophosphorylation by an intermolecular mechanism. Moreover, the suppressive and negative dominant action of defective epidermal growth factor receptor (EGFR) was shown to be caused by formation of inactive heterodimers with normal EGFR leading to diminished biological signaling. In this report we explore the structural requirements and functional significance of heterodimerization between EGFR and HER2. HER2 (also called c-erbB-2 or neu) is a member of the EGFR family whose natural ligand is still unknown. We show that in response to EGF, wild type EGFR and various EGFR mutants were able to undergo heterodimerization with HER2. Addition of EGF to transfected cells co-expressing HER2 with a kinase negative point mutant of EGFR (K721A) stimulated heterodimer formation, tyrosine phosphorylation of K721A and HER2, and tyrosine phosphorylation of one of their known substrates, phospholipase C gamma. However, the binding of EGF to transfected cells co-expressing HER2 together with another EGFR mutant CD533 (a deletion mutant lacking most of the cytoplasmic domain of EGFR) caused heterodimerization and inhibition of tyrosine kinase activity. It appears therefore that EGF-induced heterodimerization of EGFR and HER2 can promote either stimulatory or inhibitory influences on kinase activity. We propose that the nature of receptor interactions on the cell surface can either activate or inhibit the initiation of growth factor-controlled cellular signaling.


Stable expression of HB24, a diverged human homeobox gene, in T lymphocytes induces genes involved in T cell activation and growth. A diverged homeobox gene, HB24, which is known to be induced following lymphocyte activation, was introduced into Jurkat T cells under the control of a constitutive promoter. Stable transfectants of HB24 were established that expressed high levels of HB24 mRNA and possessed an altered phenotype suggestive of activated T cells. A number of genes known to be induced following T cell activation and associated with cell growth were increased in the transfectants, including c-fos, c-myc, c-myb, HLA-DR, lck, NF-kappa B, interleukin-2 and interleukin-2 receptor alpha (IL-2R alpha). Analysis of IL-2R alpha expression by transient transfection of IL-2R alpha promoter constructs into the HB24 transfectants revealed constitutive expression (about 60% of phytohemagglutinin- and phorbol ester-activated Jurkat cells) that was dependent on the kappa B site in the IL-2R alpha promoter. Furthermore, as a consequence of the increased HB24 mRNA levels, the Jurkat HB24 transfectants proliferated more rapidly than control cell lines. Thus, stable expression of HB24 confers an activation phenotype on a human T cell line, implicating this gene as an important transcriptional factor during T cell activation and growth.


Inhibition of Molt-4-endothelial adherence by synthetic peptides from the sequence of ICAM-1. Previous studies have shown that inflammatory pathologies are mediated by lymphocyte adhesion to endothelium and subsequent transmigration through the endothelial monolayer. Lymphocyte-endothelial adherence is, in part, caused by the leukocyte integrin LFA-1 binding to ICAM-1, its ligand on endothelial cells. Synthetic peptides based on specific amino acid sequences of human ICAM-1 inhibit the adherence of a lymphocytic cell line, Molt-4, to cytokine-stimulated endothelial cells. A total of 26 peptides spanning the extracellular domains of ICAM-1 were evaluated for their inhibitory activity in two cell adhesion assays. Binding of fluorescently labeled Molt-4 cells to TNF-stimulated human umbilical vein endothelial cells was inhibited reproducibly by peptides ICAM1-20, ICAM26-50, ICAM40-64, ICAM132-146, and ICAM345-375. Three overlapping sequences of the peptide ICAM40-64, KELLLPGNNRKVYELSNVQEDSQPM, were synthesized and tested as well, and the sequence KELLLPGNNRKV showed the greatest inhibition. The inhibitory activity of these peptides was confirmed using a second assay, inhibition of aggregation of the Epstein-Barr virus-transformed B-lymphoblast line JY. Polyclonal antibodies were developed in rabbits by immunization with two of the peptides and characterized for their ability to inhibit lymphocyte-endothelial adherence. These studies predict potential sites for interaction of the integrin receptor, LFA-1, with its ligand, ICAM-1. Thus lymphocyte-endothelial interaction, and resulting inflammation, may be partially mediated by the association of ICAM-1 with LFA-1 at the specific molecular locations identified in this study.


Receptor-specific desensitization with purified proteins. Kinase dependence and receptor specificity of beta-arrestin and arrestin in the beta 2-adrenergic receptor and rhodopsin systems. Homologous desensitization of beta-adrenergic receptors, as well as adaptation of rhodopsin, are thought to be triggered by specific phosphorylation of the receptor proteins. However, phosphorylation alone seems insufficient to inhibit receptor function, and it has been proposed that the inhibition is mediated, following receptor phosphorylation, by the additional proteins beta-arrestin in the case of beta-adrenergic receptors and arrestin in the case of rhodopsin. In order to test this hypothesis with isolated proteins, beta-arrestin and arrestin were produced by transient overexpression of their cDNAs in COS7 cells and purified to apparent homogeneity. Their functional effects were assessed in reconstituted receptor/G protein systems using either beta 2-adrenergic receptors with Gs or rhodopsin with Gt. Prior to the assays, beta 2-receptors and rhodopsin were phosphorylated by their specific kinases beta-adrenergic receptor kinase (beta ARK) and rhodopsin kinase, respectively. beta-Arrestin was a potent inhibitor of the function of beta ARK-phosphorylated beta 2-receptors. Half-maximal inhibition occurred at a beta-arrestin:beta 2-receptor stoichiometry of about 1:1. More than 100-fold higher concentrations of arrestin were required to inhibit beta 2-receptor function. Conversely, arrestin caused half-maximal inhibition of the function of rhodopsin kinase-phosphorylated rhodopsin when present in concentrations about equal to those of rhodopsin, whereas beta-arrestin at 100-fold higher concentrations had little inhibitory effect. The potency of beta-arrestin in inhibiting beta 2-receptor function was increased over 10-fold following phosphorylation of the receptors by beta ARK, but was not affected by receptor phosphorylation using protein kinase A. This suggests that beta-arrestin plays a role in beta ARK-mediated homologous, but not in protein kinase A-mediated heterologous desensitization of beta-adrenergic receptors. It is concluded that even though arrestin and beta-arrestin are similar proteins, they display marked specificity for their respective receptors and that phosphorylation of the receptors by the receptor-specific kinases serves to permit the inhibitory effects of the "arresting" proteins by allowing them to bind to the receptors and thereby inhibit their signaling properties. Furthermore, it is shown that this mechanism of receptor inhibition can be reproduced with isolated purified proteins.


Photolabeling of CheR methyltransferase with S-adenosyl-L-methionine (AdoMet). Studies on the AdoMet binding site. CheR methyltransferase from Salmonella typhimurium was directly photolabeled with S-adenosyl-L-[methyl-3H]methionine. The labeled protein was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and then was detected by fluorography. The methylase-S-adenosyl-L-methionine adduct was found to be stable under the experimental conditions employed. Labeling was found to be a function of the concentration of enzyme, S-adenosyl-L-methionine (AdoMet), and the intensity and time of UV irradiation. The extent of labeling and protein methylation was found to be inhibited by S-adenosyl-L-homocysteine, S-adenosyl-L-ethionine, and sinefungin, which are known to compete with AdoMet for the same binding site on the enzyme. Our earlier data showed that the enzyme has 2 cysteine residues and that these are important for enzyme activity. Here, we show that sulfhydryl reagents inhibit the photolabeling of the substrate to the enzyme, indicating the presence of cysteine in the vicinity of the substrate-binding site. We also found that when Cys31 was modified to Ser, no photolabeling of CheR was observed, whereas a modification of Cys229 to Ser had little effect on the ability of AdoMet to label the enzyme. This suggests that Cys31 is located at or near AdoMet-binding site. The labeled protein was cleaved at tryptophan residues, generating two major fragments, each containing 1 cysteine residue. SDS-PAGE and fluorography of the cleaved products indicated the presence of the label being associated with the Cys31 fragment. Similar results were obtained when the labeled protein was cleaved at glutamic acid residues using V8 protease. A tryptic digest of the labeled protein showed two radioactive peptide peaks when subjected to separation on reverse phase high pressure liquid chromatography. The labeled peptides were further digested to free amino acids, and the labeled amino acid was identified as S-methylcysteine by thin layer chromatography. These results indicate that Cys31 may be involved with substrate binding, as well as with catalysis.


Post-translational glycosylation and proteolytic processing of a lysyl oxidase precursor. The synthesis and post-translational processing of a lysyl oxidase precursor protein predicted by the cDNA sequence of rat aorta lysyl oxidase were investigated. In vitro transcription of the cloned lysyl oxidase cDNA and cell-free translation of its mRNA transcript yielded a 47-kDa protein in the absence and a 50-kDa glycosylated protein in the presence of pancreatic membranes, each of which were immunoprecipitated with antibody against the 32-kDa bovine enzyme. Similarly, an N-glycosylated, 50-kDa protein band was synthesized by and immunoprecipitated from cultured neonatal rat aorta smooth muscle cells labeled with [35S]methionine. Pulse-chase studies of proteins newly synthesized by these cells demonstrated that the glycosylated 50-kDa precursor is secreted and that it is processed to the 32-kDa molecular form of lysyl oxidase principally in the medium. The presence of an extracellular processing enzyme activity which converts the 50-kDa precursor to the 32-kDa species was demonstrated by incubating conditioned medium of neonatal rat aorta smooth muscle cell cultures as a source of processing activity with conditioned medium containing 35S-labeled precursor synthesized but not processed by a tumorigenic cell line transfected with a lysyl oxidase expression vector. In contrast to the 50-kDa species, the 32-kDa protein does not appear to be N-glycosylated consistent with the loss of N-linked oligosaccharide units during the processing to the smaller species. The modes of biosynthesis and secretion of lysyl oxidase are discussed in terms of other nonproteolytic activities required for activation of prolysyl oxidase.


Immunolocalization of cytoplasmic dynein to lysosomes in cultured cells. Polyclonal antisera have been raised against cytoplasmic dynein purified from calf brain and rat testis. These antibodies reacted most strongly with the 74 kDa dynein intermediate chain, but also recognized the 410 kDa heavy chain, and the 150 and 45 kDa polypeptides previously observed to copurify with cytoplasmic dynein from rat tissues. Localization studies were performed by indirect immunofluorescence microscopy using a fibroblast cell line. Dynein-specific staining appeared vesicular, distributed throughout the cell, but more concentrated near the nucleus. Double-labeling studies using fluorescent markers for membranous organelles indicated a co-localization of dynein with lysosomes. The distribution of the dynein-positive lysosomes was disrupted by treatment of the cells with microtubule-active drugs, and by acidification of the cytoplasm. Comparison of the distribution of lysosomes with peripheral microtubules indicated a high degree of coincidence. These results are consistent with the hypothesis that cytoplasmic dynein is involved in retrograde-directed movement of membranous organelles. In mitotic cells, dynein staining was also apparent along the microtubules of the mitotic apparatus, though vesicular staining was still conspicuous. The presence of dynein on vesicles as well as on spindle microtubules indicates that dynein distribution between these compartments may be regulated by distinct binding proteins.


NMR determination of the TCA cycle rate and alpha-ketoglutarate/glutamate exchange rate in rat brain. A mathematical model of cerebral glucose metabolism was developed to analyze the isotopic labeling of carbon atoms C4 and C3 of glutamate following an intravenous infusion of [1-13C]glucose. The model consists of a series of coupled metabolic pools representing glucose, glycolytic intermediates, tricarboxylic acid (TCA) cycle intermediates, glutamate, aspartate, and glutamine. Based on the rate of 13C isotopic labeling of glutamate C4 measured in a previous study, the TCA cycle rate in rat brain was determined to be 1.58 +/- 0.41 mumol min-1 g-1 (mean +/- SD, n = 5). Analysis of the difference between the rates of isotopic enrichment of glutamate C4 and C3 permitted the rate of exchange between alpha-ketoglutarate (alpha-KG) and glutamate to be assessed in vivo. In rat brain, the exchange rate between alpha-KG and glutamate is between 89 +/- 35 and 126 +/- 22 times faster than the TCA cycle rate (mean +/- SD, n = 4). The sensitivity of the calculated value of the TCA cycle rate to other metabolic fluxes and to concentrations of glycolytic and TCA cycle intermediates was tested and found to be small.


Regional difference in the response mediated by beta 1-adrenoceptor subtype in bovine cerebral arteries. Helical strips of bovine rostral cerebral arteries (anterior cerebral, middle cerebral, and internal carotid artery) responded to norepinephrine with contractions, whereas the caudal cerebral arteries (posterior communicating, posterior cerebral, and basilar artery) relaxed in response to the amine. After blockade of alpha-adrenoceptors, norepinephrine-induced rostral artery contractions were reversed to relaxations, which were smaller than those in the caudal arteries. Isoproterenol, dobutamine, and terbutaline produced greater relaxations in caudal than in rostral arteries, but forskolin relaxed these arteries to a similar magnitude. The isoproterenol-induced relaxation was not affected by removal of the endothelium. Maximal relaxations induced by terbutaline in caudal arteries were much inferior to those by isoproterenol, norepinephrine, and dobutamine. Relaxations caused by isoproterenol, norepinephrine, and terbutaline in the caudal arteries were attenuated by metoprolol, but not influenced by butoxamine. Relaxations mediated possibly by beta 1-adrenoceptor subtypes are greater in bovine caudal cerebral arteries than in the rostral arteries. The heterogeneity does not appear to be associated with the different ability of cyclic AMP to relax arterial smooth muscle but with the difference of beta-adrenoceptor populations and/or processes from the receptors to adenylate cyclase.


In vitro and in vivo detection of somatostatin receptors in pheochromocytomas and paragangliomas. Fifty-one adrenal pheochromocytomas and 14 paragangliomas were evaluated for somatostatin (SRIH) receptor content with in vitro autoradiography on tissue sections from surgically removed tumors, using iodinated 125I[Tyr]3 octreotide as radioligand. Thirty-seven of 51 pheochromocytomas were SRIH receptor positive (73%), as well as 13 of 14 paragangliomas (93%). These SRIH receptors were of high affinity, pharmacologically specific for SRIH and localized on the tumor tissue. Using in vivo imaging techniques with radiolabeled SRIH analogs, paragangliomas could be visualized in five patients, as well as pheochromocytomas in two of three patients. All tumors tested subsequently in vitro (n = 7) were shown to contain SRIH receptors. A majority of pheochromocytomas were also shown to have a high tumoral SRIH content as measured by immunohistochemical techniques. Detection of SRIH messenger RNA in pheochromocytomas by in situ hybridization indicated that the SRIH was produced in the tumors. A weak inverse correlation was observed between SRIH receptor status and tumoral SRIH content, suggesting that SRIH receptors may be down-regulated by high levels of endogenous SRIH in some tumors. There was no correlation between the SRIH receptor status and sex, age, tumor size, benign vs. malignant tumor, or urinary metanephrine excretion. These tumors were also analyzed for allelic losses on various chromosomes and showed significant loss of heterozygosity (LOH) on chromosomes 1p, 3p, 17p, and 22q. All eight tumors with LOH on chromosome 1p were SRIH receptor positive (100%), whereas only 6 of 11 tumors without LOH on 1p (55%) were SRIH receptor positive, suggesting a correlation between LOH on 1p and SRIH receptor positive status. SRIH receptors thus represent a consistent pathobiochemical marker for most of these adrenal and extra-adrenal tumors. In addition, these receptors may be of potential interest for the in vivo localization of these tumors.


Hyperthyroid Graves' disease without detectable thyrotropin receptor antibodies. TSH receptor antibodies are generally held responsible for the stimulation of the thyroid that characterizes patients with Graves' disease. Here, we describe nine patients with hyperthyroidism (triiodothyronine 4.9, 3.2-6.7 nmol/L; median, range) who were referred for radioiodine treatment and who had increased thyroid radioiodine uptake values but lacked TSH receptor antibodies determined by a radioreceptor assay. Furthermore, when serum immunoglobulins were studied in a bioassay based on a rat thyroid cell line (FRTL-5), no evidence of stimulant activity was observed. Subsequent to radioiodine therapy, TSH receptor antibodies appeared in all nine patients. The antibodies competed for TSH in the radioreceptor assay and, of the eight patient samples studied with the bioassay, six stimulated cAMP production whereas another two blocked the latter. The results show that a small proportion of patients with active hyperthyroid Graves' disease, in this study 9 out of 130 cases, do not have detectable TSH receptor stimulatory antibodies. A local production of antibodies within the thyroid can be suggested, although a more likely explanation might be that the thyroid in Graves' disease is activated also by other mechanisms than antibody-dependent ones.


Clonal analysis of human tumors with M27 beta, a highly informative polymorphic X chromosomal probe. The clonality of human tumors can be studied by X inactivation/methylation analysis in female patients heterozygous for X-linked DNA polymorphisms. We present a detailed study on clonal tumor analysis with M27 beta, a highly informative probe detecting a polymorphic X chromosomal locus, DXS255. The polymorphism detected at this locus is due to variable numbers of tandem repeats. The rate of constitutional heterozygosity detected by M27 beta was 88%. Normal tissue from gastrointestinal mucosa and thyroid showed random, hence polyclonal, patterns. Nonrandom clonal X inactivation was detected in all 22 malignant neoplasms that had been shown to be clonal by other DNA markers, such as antigen receptor gene rearrangements or clonal loss of heterozygosity at 17p and other loci. 16/48 normal blood leukocyte samples (33%) showed considerably skewed X inactivation patterns. Comparison of blood leukocytes and normal tissue indicated that in a given individual, X inactivation patterns may be tissue specific. M27 beta was used to study the clonal composition of 13 benign thyroid nodules from 12 multinodular goiters with rapid recent growth, traditionally termed "adenomas." Nine of them were clonal, whereas four nodules and tissue from a case of Graves' goiter were not, indicating that some, but not all, such thyroid nodules may represent true clonal neoplasms. The M27 beta probe permits one to study the clonal composition by the X inactivation approach of a wide variety of solid tumors from most female patients. As a control, normal tissue homologous to the tumor type of interest is preferable to DNA from blood leukocytes, since the latter may show nonrandom X inactivation patterns in a fairly high proportion of cases. M27 beta may, therefore, be of limited use for the clonal analysis of neoplasms derived from hematopoietic cells.


Intracellular signaling in the regulation of renal Na-K-ATPase. I. Role of cyclic AMP and phospholipase A2. We have reported that dopamine (DA) inhibits Na-K-ATPase activity in the cortical collecting duct (CCD) by stimulating the DA1 receptor, and the present study was designed to evaluate the mechanism of this effect. Short-term exposure (15-30 min) of microdissected rat CCD to DA, a DA1 agonist (fenoldopam), vasopressin (AVP), forskolin, or dibutyryl cAMP (dBcAMP), which increase cAMP content by different mechanisms, strongly (approximately 60%) inhibited Na-K-ATPase activity. 2',5'-dideoxyadenosine, an inhibitor of adenylate cyclase, completely blocked Na-K-ATPase inhibition by DA or fenoldopam, and IP20, an inhibitor peptide of cAMP-dependent protein kinase A (PKA), abolished the Na:K pump effect of all the cAMP agonists listed above. To verify whether the mechanism of pump inhibition by agents that increase cell cAMP involves phospholipase A2 (PLA2), we used mepacrine, a PLA2 inhibitor, which also abolished Na-K-ATPase inhibition by DA or fenoldopam, as well as by AVP, forskolin, or dBcAMP. Arachidonic acid (10(-7) - 10(-4) M) inhibited Na-K-ATPase activity in dose-dependent fashion. Corticosterone, which induces lipomodulin, a PLA2 inhibitor protein inactivated by PKA, equally abolished the pump effects of DA, fenoldopam, forskolin, and dBcAMP, suggesting that lipomodulin might act between PKA and PLA2 in cAMP-dependent pump regulation. We conclude that dopamine inhibits Na-K-ATPase activity in the CCD through a DA1 receptor-mediated cAMP-PKA pathway that involves the stimulation of PLA2 and arachidonic acid release, possibly mediated by inactivation of lipomodulin. This pathway is shared by other agonists that increase cell cAMP and thus stimulate PKA activity.


Antihypertensive and metabolic effects of concomitant administration of terazosin and methyclothiazide for the treatment of essential hypertension. The efficacy and safety of once-daily 2.5- or 5.0-mg methyclothiazide (MCTZ) added to once-daily 5.0-mg terazosin (TRZ) versus 5.0-mg TRZ alone was evaluated in this double-blind, multicenter study. All patients received TRZ during a 6-week titration period. Hypertensive patients (222) (mean blood pressure of 159/104 mm Hg) were randomized to one of three treatment groups: TRZ alone (N = 76); TRZ+MCTZ-2.5 mg (N = 74); and TRZ+MCTZ-5.0 mg (N = 72) for the 8-week double-blind period. Changes in the supine and standing SBP/DBP from preTRZ period were: TRZ alone (-4.8/-8.1 and -2.6/-6.1 mm Hg); TRZ+MCTZ-2.5 mg (-17.3/-12.4 and -16.0/-11.2 mm Hg); and TRZ+MCTZ-5.0 mg (-20.6/-14.4 and -23.3/-14.6 mm Hg). Blood pressure changes in the combination groups were significantly greater than those in the TRZ alone group. However, there were no statistically significant differences between the TRZ+MCTZ-2.5-mg and TRZ+MCTZ-5.0-mg groups. The combination of TRZ and MCTZ tends to mitigate the adverse effects on serum glucose, uric, potassium and lipids usually associated with thiazide diuretics. Thus, combination treatment that begins with TRZ and adds MCTZ is effective in lowering blood pressure without any significant adverse metabolic effects.


Sunscreens protect epidermal Langerhans cells and Thy-1+ cells but not local contact sensitization from the effects of ultraviolet light. This study compares the ability of two commonly used sunscreens--octyl dimethyl para-aminobenzoate (Padimate O) and 2-ethylhexyl-p-methoxycinnamate (2-EHMC)--to protect Langerhans cells (LC), Thy-1+ dendritic epidermal cells (Thy-1+ dEC), and local contact sensitivity (CS) from the effects of ultraviolet (UV) light. Chronic exposure of mice 5 d per week for 4 weeks with an intermediate dose of solar-simulated sunlight from which any UVC had been filtered reduced the LC and Thy-1+ dEC density of murine epidermis. This irradiation procedure was designed to simulate closely the daily exposure of humans to sunlight. This effect on LC and Thy-1+ dEC occurred in both albino and pigmented mice that develop a tan during the irradiation procedure, indicating that a tan does not protect these cells from the effects of UV light. Sunscreen preparations with Padimate O and 2-EHMC, both of which also contained benzophenone-3, as well as Padimate O or 2-EHMC in organic solvent, inhibited UV light from depleting LC from the epidermis of both mouse strains. Padimate O and 2-EHMC in organic solvent were used to ensure that these were the active ingredients in the sunscreen preparations. In contrast to the effects on LC, Padimate O, but not 2-EHMC, protected Thy-1+ dEC from UV exposure in both mouse strains, but neither protected against the development of local immunosuppression using a contact sensitivity model. Thus, even in a mouse strain that is sensitive to UV-induced immunosuppression, local immunosuppression can occur in the presence of normal densities of LC and Thy-1+ dEC.


Minoxidil sulfotransferase, a marker of human keratinocyte differentiation. The sulfation of minoxidil is catalyzed by a sulfotransferase activity in a number of tissues including skin. To investigate further the nature of the minoxidil sulfotransferase activity in epithelial tissue and to compare this activity to that of cholesterol sulfotransferase, which has already been shown to be induced during the differentiation of epithelial cells, we cultured normal human epidermal keratinocytes in a keratinocyte growth medium for 4 d, after which the media were replaced with either the same growth media or media with increasing Ca++ concentrations. Cholesterol sulfotransferase, minoxidil sulfotransferase, and transglutaminase were determined during the differentiation of the cells in the three media. Time-activity curves that suggested two different sulfotransferase activities were induced during the differentiation process. U-77581, a competitive inhibitor of minoxidil sulfotransferase activity, inhibited the sulfation of minoxidil sulfotransferase activity in the keratinocyte homogenates, but it did not inhibit the sulfation of cholesterol. These data indicate that at least two sulfotransferase activities are induced during the differentiation of epithelial keratinocytes and minoxidil sulfotransferase is an early marker of that differentiation.


Zidovudine-interferon-alpha combination therapy in patients with advanced human immunodeficiency virus type 1 infection: biphasic response of p24 antigen and quantitative polymerase chain reaction. In an open-label dose-ranging pilot trial, 13 homosexual men with human immunodeficiency virus type 1 (HIV-1) p24 antigenemia after at least 6 weeks of zidovudine monotherapy were continued on zidovudine and given interferon-alpha, 1.25-7.5 x 10(6) units/m2 subcutaneously three times/week. Plasma p24 antigen levels demonstrated a biphasic response, falling initially in 11 patients by a mean of 50% (95% confidence interval, 36%-64%; P = .001) at a median of 11 weeks, but rising steadily thereafter (P = .001). CD4+ cell counts fell by a mean of 7.1 cells/mm3/week (P = .01). Higher initial CD4+ counts predicted greater p24 antigen reductions. At higher interferon doses no greater reductions in p24 antigen occurred, but side effects were more severe and CD4+ lymphocyte counts fell faster. Polymerase chain reaction quantification of HIV-1 DNA in 3 patients showed a biphasic pattern paralleling the p24 antigen response. In sum, although evidence of short-term effects was found, the combination showed no evidence of lasting antiviral activity beyond that achieved with zidovudine alone in patients with advanced HIV-1 infection.


Naturally occurring soluble CD4 in patients with human immunodeficiency virus infection. To investigate its use as a marker of disease severity, serum soluble CD4 (sCD4) was measured by ELISA in patients with human immunodeficiency virus (HIV) infection. Levels of sCD4 were higher in patients than in controls (P less than .001) but did not increase with disease severity. sCD4 release per CD4 lymphocyte showed a linear increase with disease severity and performed as well as beta 2-microglobulin, a widely used marker. To study the role of sCD4 in the pathogenesis of HIV infection, an ELISA to detect sCD4 complexed with glycoprotein 120 (gp120) HIV envelope protein was developed. Preformed sCD4-gp120 complexes were not detectable in patient serum, but addition of recombinant gp120 showed that circulating sCD4 is capable of binding HIV envelope proteins. This study indicates that the sCD4-to-CD4 lymphocyte ratio increases linearly with disease severity and may be a useful marker of CD4 lymphocyte damage. In addition, serum sCD4 can bind viral particles, which may have implications for the use of recombinant sCD4 as a therapy in HIV infection.


Detection of nephropathia epidemica virus RNA in patient samples using a nested primer-based polymerase chain reaction. A nested primer-based polymerase chain reaction was constructed for the detection of Puumala virus RNA in patient samples. Puumala virus RNA was detected in cells from the urinary and the respiratory tracts and in peripheral blood mononuclear cells of patients with nephropathia epidemica. After inoculation with nephropathia epidemica patient material on Vero E6 cells and propagation for nine passages (4 months), Puumala virus RNA was detected at every passage. Hybridization under high-stringency conditions revealed that the overall nucleotide homology between the different patient isolates and the prototype strain (Puumala) is high. Using cDNA from Hällnäs B1 strain as a probe, hybridization occurred only under low-stringency conditions.


Human breast cancer: prognostic significance of the c-erbB-2 oncoprotein compared with epidermal growth factor receptor, DNA ploidy, and conventional pathologic features. A study was undertaken to define the prognostic value of the expression of the c-erbB-2 oncoprotein in a series of breast cancer patients when compared by multivariate analysis with expression of the epidermal growth factor receptor (EGFR), DNA ploidy, and conventional clinicopathologic features. Prognostic indicators were analyzed in 165 primary breast cancers. The c-erbB-2 oncoprotein was recognized by the polyclonal antibody 21N using an immunocytochemical method. Expression of the EGFR was stated immunocytochemically using the monoclonal antibody EGFR1. DNA ploidy was assessed in paraffin-embedded sections using a standard flow-cytometric method. Overall, 27% of carcinomas had membrane 21N-staining and were classified as c-erbB-2-positive. Overexpression of the c-erbB-2 oncoprotein was poorly associated with EGFR expression and the conventional pathologic features, and it was weakly associated with DNA ploidy and nodal status. Univariate analysis showed that c-erbB-2 expression, nodal status, DNA ploidy, and EGFR provided significant prognostic information concerning 4-year relapse-free survival (RFS) with the odds ratios (ORs) of not relapsing of 2.94, 2.83, 2.34, and 2.20, respectively. Regarding overall survival (OS) at 4 years, only nodal status and DNA ploidy had prognostic significance, with the ORs of not dying of 2.68 and 2.80, respectively. Applying multivariate analysis to RFS, 21N when adjusted for nodal status, EGFR, and DNA ploidy (full model) failed to retain prognostic value (P = .202), whereas nodal status was the most significant indicator of relapse (P = .027) followed by DNA ploidy (P = .056) and EGFR (P = .093). This study suggests that overexpression of the c-erbB-2 oncoprotein appears to be an important indicator of relapse in stage I-II breast cancer when singly evaluated. Multivariate analysis shows that the determination both of nodal status and DNA ploidy improves our ability to identify subsets of patients with different prognoses, and allows for a better selection of patients for systemic adjuvant treatments.


Low-threshold Ca2+ channels mediate induction of long-term potentiation in kitten visual cortex. 1. The induction mechanism of long-term potentiation (LTP) in developing visual cortex was studied by recording intracellular responses from layer III-IV cells in slice preparations of kitten visual cortex at 30-40 days after birth. 2. Strong stimulation of white matter produced a late depolarizing response after an orthodromic action potential. This depolarizing response was abolished by membrane depolarization or hyperpolarization caused by current injection through the recording electrode. In addition, this response was reduced by bath application of a low concentration (100 microM) of Ni2+ without any changes in the rising slope of the excitatory postsynaptic potential (EPSP) or orthodromic action potential. This suggests that this response is mediated by low-threshold Ca2+ channels (LTCs). 3. The involvement of LTCs in the induction of LTP was tested. White matter was stimulated at 2 Hz for 15 min as a conditioning stimulus to induce LTP, and the resultant changes in EPSPs were tested by low-frequency (0.1 Hz) stimulation of white matter. Conditioning stimulation produced a large N-methyl-D-aspartate (NMDA) receptor-mediated depolarizing response in these cells, which obscured the presence of the late depoliarzation. Therefore the test was conducted in a solution containing an NMDA antagonist 2-amino-5-phosphonovalerate (APV). 4. Weak conditioning stimulation, which evoked no LTC responses, never induced LTP; whereas strong conditioning stimulation, which evoked LTC responses, always induced LTP. Strong conditioning stimulation failed to induce LTP when LTC responses were prevented either by membrane depolarization or hyperpolarization or by a bath application of 100 microM Ni2+. 5. In a solution without APV, the application of Ni2+ also prevented the induction of LTP. 6. When cells were impaled by an electrode containing a Ca2+ chelator 1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), LTP was never induced, even though LTC responses were evoked by conditioning stimulation. These results indicate that Ca2+ influx into postsynaptic cells through LTCs induces the LTP. 7. The responses mediated by LTCs, which were evoked by the injection of current pulses into the cells, were maximum at the critical period of visual cortical plasticity, suggesting that LTCs in postsynaptic cells regulate the plastic changes in developing visual cortex.


Kindling-induced long-lasting changes in synaptic transmission in the basolateral amygdala. 1. Intracellular current-clamp recordings were obtained from neurons of the basolateral amygdala (BLA) in an in vitro slice preparation from control and kindled animals. Postsynaptic potentials, elicited by stimulation of the stria terminalis (ST) or lateral amygdaloid nucleus (LA), were used to investigate the role of excitatory and inhibitory amino acid transmission in kindling-induced epileptiform activity. The contributions of glutamatergic and GABAergic receptor subtypes were analyzed by use of the non-N-methyl-D-aspartate (non-NMDA) antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), the NMDA antagonist DL-2-amino-5-phosphonovaleric acid (APV), and the GABAA antagonist bicuculline methiodide (BMI). 2. The synaptic waveform evoked in control neurons consisted of an excitatory postsynaptic potential (EPSP), a fast inhibitory postsynaptic potential (f-IPSP), and a slow inhibitory postsynaptic potential (s-IPSP). Stimulation of the ST or LA pathways evoked a burst-firing response in BLA neurons contralateral from the site of stimulation of kindled animals. 3. APV (50 microM) reduced, but CNQX (10 microM) completely blocked, the burst-firing response in BLA neurons from kindled animals and bicuculline-induced bursting in control neurons. 4. Kindling significantly increased the amplitude of both the slow NMDA- and the fast non-NMDA-receptor-mediated components of synaptic transmission (s- and f-EPSPs, respectively). Furthermore, the stimulus intensities required to evoke EPSPs just subthreshold for action potential generation were significantly lower in slices from kindled animals. 5. In kindled neurons no significant change was observed in the membrane input resistance and resting membrane potential or in the number of action potentials elicited in response to depolarizating current injection. 6. Kindling resulted in a pathway-specific loss of ST- and LA-evoked feedforward GABAergic synaptic transmission and of spontaneous IPSPs. In the same BLA neurons, direct GABAergic inhibition via stimulation of the LA was not affected by kindling. 7. The enhanced glutamatergic transmission was not due to disinhibition, because, in the presence of BMI (and CNQX to prevent BMI-induced bursting), the s-EPSP amplitude was still greater in kindled than in control neurons. 8. These results provide evidence that the epileptiform activity observed in BLA neurons after kindling results from an increase in excitatory NMDA- and non-NMDA-receptor-mediated glutamatergic transmission and a decrease in inhibitory gamma-aminobutyric acid (GABA)-receptor-mediated transmission; the enhanced excitatory transmission cannot be accounted for by reduced inhibition.(ABSTRACT TRUNCATED AT 400 WORDS)


Presynaptic modulation by GABAB receptors of glutamatergic excitation and GABAergic inhibition of neostriatal neurons. 1. The present experiments investigated the effects of gamma-amino-butyric acidB (GABAB) receptor stimulation on the excitatory and inhibitory responses of neostriatal neurons evoked by stimulation of the subcortical white matter in a rat neostriatal slice preparation. 2. Intracellular recordings showed that single-impulse stimulation of the corpus callosum evoked monosynaptic, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX)-sensitive excitatory postsynaptic potentials (EPSPs) that were attenuated by the GABAB receptor agonist, p-chlorophenyl-GABA (baclofen, 0.5-10 microM) in a concentration-dependent manner. Baclofen also blocked the GABAA-mediated inhibition of neostriatal cell responses, which were revealed by paired-impulse stimulation of the subcortical white matter. Both of these effects persisted in slices in which the anterior cortex was removed, indicating that the site of action for baclofen was intrinsic to the neostriatum. The GABAB antagonist 3-amino-2-hydroxy-2-(4-chlorophenyl)-propanesulfonic acid (saclofen, 250-500 microM) reversed the depressant actions of baclofen on both the excitatory and inhibitory responses of neostriatal cells. 3. Concentrations of baclofen as high as 100 microM, which markedly attenuated EPSP amplitude, did not exert direct effects on resting membrane potential, current-voltage relationship, input resistance, or spike threshold and thus appeared to have no postsynaptic effect on the population of neurons recorded. 4. These results indicate that, in contrast to other regions of the CNS, the depressant effects of baclofen on glutamate-dependent EPSPs are mediated exclusively through GABAB receptors located presynaptically on the terminals of glutamatergic afferents.(ABSTRACT TRUNCATED AT 250 WORDS)


Somatostatin receptor scintigraphy with indium-111-DTPA-D-Phe-1-octreotide in man: metabolism, dosimetry and comparison with iodine-123-Tyr-3-octreotide. Scintigraphy with 123I-Tyr-3-octreotide has several major drawbacks as regards its metabolic behavior, its cumbersome preparation and the short physical half-life of the radionuclide. The use of another radiolabeled analog of somatostatin, 111In-DTPA-D-Phe-1-octreotide, has consequently been proposed. DTPA-D-Phe-1-octreotide can be radiolabeled with 111In in an easy single-step procedure. DTPA-D-Phe-1-octreotide is cleared predominantly via the kidneys. Fecal excretion of radioactivity amounts to only a few percent of the administered radioactivity. For the radiation dose to normal tissues, the most important organs are the kidneys, the spleen, the urinary bladder, the liver and the remainder of the body. The calculated effective dose equivalent is 0.08 mSv/MBq. Optimal 111In-DTPA-D-Phe-1-octreotide scintigraphic imaging of various somatostatin receptor-positive tumors was obtained 24 hr after injection. In the six patients studied, tumor localization with 123I-Tyr-3-octreotide and with 111In-DTPA-D-Phe-1-octreotide were found to be similar. However, the normal pituitary is more frequently visualized with the latter radiopharmaceutical. In conclusion, 111In-DTPA-D-Phe-1-octreotide appears to be a sensitive somatostatin receptor-positive tissue-seeking radiopharmaceutical with some remarkable advantages: easy preparation, general availability, appropriate half-life and absence of major interference in the upper abdominal region, because of its renal clearance. Therefore, 111In-DTPA-D-Phe-1-octreotide may be suitable for use in SPECT of the abdomen, which is important in the localization of small endocrine gastroenteropancreatic tumors.


Effects of beta-adrenergic blockade in an osteoblast-like cell line. The beta-adrenergic blocking agent propranolol was shown in previous studies to increase orthotopic bone formation in rats. To understand the cellular mechanisms underlying this observation, propranolol was tested for its effects on osteoblastic cells, which possess adenylate cyclase-coupled beta-adrenergic receptors. The ability of propranolol to modulate parathyroid hormone (PTH) and isoproterenol effects on adenylate cyclase activity and on alkaline phosphatase expression was studied in the osteoblast-like rat osteosarcoma cell line ROS 17/2.8. At concentrations between 0.1 and 10 microM, DL-propranolol specifically inhibited adenylate cyclase stimulation by the beta-adrenergic agonist isoproterenol, but did not alter either basal or PTH-stimulated activity. At these concentrations, propranolol also blunted the inhibition of alkaline phosphatase activity by isoproterenol but not PTH. Propranolol alone had minimal effects on ROS alkaline phosphatase activity at low concentrations (0.1-1 microM), but became inhibitory at high concentrations (10-100 microM). Thus, the direct effects of physiologically relevant propranolol concentrations on osteoblastic cells can be attributed principally to beta-adrenergic blockade. These findings further suggest that propranolol may enhance bone formation by preserving osteoblastic activity in the face of inhibition by beta-adrenergic agonists.


Effect of additives on the crystallization of glutamate dehydrogenase from Clostridium symbiosum. Evidence for a ligand-induced conformational change. A new crystal form of the hexameric NAD(+)-linked glutamate dehydrogenase (GDH) from Clostridium symbiosum has been grown using the hanging drop method of vapour diffusion. The crystals are obtained either by using high concentrations of the amino acid substrate of the enzyme, glutamate, as the precipitant or by co-crystallization from ammonium sulphate in the presence of either p-chloromercuribenzene sulphonate or potassium tetracyanoplatinate. The crystals diffract well and X-ray photographs have established that they are in the space group R32. Considerations of the values of Vm indicate that the asymmetric unit of the R32 crystals contains a single subunit. Packing considerations based on the structure of the native enzyme determined from a different crystal form suggest that the molecule must undergo a significant conformational change in order to be accommodated in the new cell. Such a conformational rearrangement may represent an important step in the catalytic cycle.


Various methods of analysis of mdr-1/P-glycoprotein in human colon cancer cell lines. Multidrug resistance (MDR) mediated by high levels of mdr-1 (also known as PGY1)/P-glycoprotein (Pgp) has been studied in tissue culture systems; however, most tumor samples which express mdr-1/Pgp have much lower levels. We wanted to determine if levels seen clinically could be detected by commonly used methods and to determine if these levels conferred MDR reversible by Pgp antagonists. We studied multi-drug-resistant cell lines and sublines with levels of mdr-1/Pgp expression comparable to those seen clinically. We evaluated the expression of mdr-1 RNA by Northern blot analysis, slot blot analysis, polymerase chain reaction (PCR) analysis, and in situ hybridization. We evaluated protein expression by immunofluorescence, immunohistochemistry, fluorescence-activated cell sorting, and immunoblotting analyses. Drug resistance and reversibility were determined by cell growth during continuous drug exposure. In most cases, the low level of mdr-1/Pgp present in these cell lines could be detected by each method, but the assays were at the limit of sensitivity for all methods except the PCR method. These low levels of mdr-1/Pgp are capable of conferring MDR, which can be antagonized by verapamil. Levels of mdr-1/Pgp similar to those found in clinical samples can be detected by each of these methods, but the PCR method was the most sensitive and most reliably quantitative. In vitro sensitization by the addition of verapamil in cell lines with these low levels of mdr-1/Pgp suggests that clinically detected levels may confer drug resistance in vivo.


Laparoscopic orchiectomy and contralateral vasectomy in a patient with an abdominal testicle: a case report. We present a case of a 38-year-old man with a unilateral intra-abdominal testicle and undesired fertility in whom orchiectomy and contralateral vasectomy were performed laparoscopically. Urologists have been using diagnostic laparoscopy in patients with nonpalpable testes to plan the definitive procedure when the testicle is present, and to avoid laparotomy in cases of testicular absence. This case of laparoscopic orchiectomy and vasectomy demonstrates that operative laparoscopy allows another subset of patients with cryptorchidism to avoid open laparotomy.


[Immunohistological study on the expression of proliferating cell nuclear antigen (PCNA/cyclin) in human colorectal lesions]. The purpose of this study was to clarify the significance of immunohistological staining for PCNA/cyclin in human colorectal lesions. Our results: The PCNA-positive cells existed at the bottom of colonic tubuli in the normal and hyperplastic conditions. In the neoplastic lesions, however, the positive cells were existed at the relatively surface of the mucosa (chi 2: P less than 0.01) and distributed irregularly from the bottom to the top of carcinoma tissue. These results suggested that immunohistological staining for PCNA would specifically detect the cell proliferation and be beneficial for practical use and clinical application of the diagnosis of the colorectal lesions.


[Diagnosis of dominant renal polycystosis in adults by analysis of DNA polymorphism]. Adult renal polycystosis (ARP) is a dominant autosomic disease. The gene responsible for this disease in most families has been located on the short arm of chromosome 16 (16 p) by restriction analysis of the DNA polymorphisms (RFLP). The existence of several polymorphic markers flanking this gene permits the diagnosis of any member of an affected family. A series of proximal and distal genetic markers have been used to study the segregation of the disease in a group of families with more than one affected member. The clinical and genetic results obtained from a study of 10 Spanish families with ARP have been reported. A high percentage of the members under 30 years of age (40%) did not present renal cysts. Restriction analysis of DNA are fundamentally for a disease in which a high percentage of carriers remain asymptomatic within the reproductive age.


Randomised controlled trial of effect of fish-oil supplementation on pregnancy duration. The high birthweights and long duration of pregnancy in the Faroe Islands led us to suggest that a high intake of marine-fat-derived n-3 fatty acids might prolong pregnancy by shifting the balance of production of prostaglandins involved in parturition. We have compared the effects on pregnancy duration, birthweight, and birth length of a fish-oil supplement, a control olive-oil supplement, and no supplementation. 533 healthy Danish women in week 30 of pregnancy were randomly assigned in a ratio of 2/1/1 to fish oil (four 1 g Pikasol capsules [containing 2.7 g n-3 fatty acids] per day), olive oil (four 1 g capsules per day), or no supplement. The three groups differed in mean length of gestation (p = 0.006), which was highest in the fish-oil group and lowest in the olive-oil group; the result was similar when the analysis was restricted to women with an estimate of gestation length based on early ultrasound findings (443 women). Pregnancies in the fish-oil group were on average 4.0 (95% confidence interval 1.5-6.4) days longer than those in the olive-oil group; the difference in birthweight was 107 (1-214) g. The effect of supplementation on length of gestation was influenced by intake of fish and of fish oil: the difference between fish-oil and other groups was increased by a low fish intake at baseline. Fish-oil supplementation in the third trimester seems to prolong pregnancy without detrimental effects on the growth of the fetus or on the course of labour.


Risk factors for mother-to-child transmission of HIV-1. Children born to women known to be infected with human immunodeficiency virus type 1 (HIV-1) before delivery were followed prospectively from birth in nineteen European centres. This analysis, encompassing the period end-December, 1984, to beginning-August, 1991, focuses on risk factors for mother-to-child transmission of HIV-1 infection. Rate of vertical transmission, based on 721 children born to 701 mothers more than 18 months before the time of analysis, was 14.4% (95% Cl 12.0-17.1%). Transmission was associated with maternal p24-antigenaemia and a CD4 count of less than 700/microliters. In a multivariate analysis, odds ratios of transmission were: 2.25 (95% Cl 0.97-5.23) in breastfed children vs never-breastfed children; 3.80 (1.62-8.91) in children born before 34 weeks' gestation; and 0.56 (0.30-1.04) in children delivered by caesarean section. Transmission was higher with vaginal deliveries in which episiotomy, scalp electrodes, forceps, or vacuum extractors were used, but only in centres where these procedures were not routine. On the basis of these results, HIV-infected women contemplating pregnancy should be counselled according to their immunological findings and, if they have p24-antigenaemia or a low CD4 count, warned of an increased risk of viral transmission. Caesarean deliveries may have a protective effect, although it is premature to recommend routine operative delivery. The mechanism for the higher infection rate in children born before 34 weeks' gestation is unclear, but could reflect inadequate passive or active immunity at that age, combined with substantial transmission during labour or delivery. The balance of evidence suggests that mothers with established infection can transmit HIV infection through breastmilk, although the relative importance of this route remains to be defined.


Detection of mycobacterial DNA in sarcoidosis and tuberculosis with polymerase chain reaction. The cause of sarcoidosis is unknown. However, the histological similarity between the disorder and tuberculosis suggests that mycobacteria might contribute to the pathogenesis of sarcoidosis. We have used the polymerase chain reaction (PCR) to detect mycobacterial DNA in clinical samples from patients with sarcoidosis. 104 patients were included in the study (62 referred for possible tuberculosis and 20 for possible sarcoidosis, and 22 control patients who had undergone bronchoscopy for other reasons). Bronchoalveolar lavage samples, bronchial washings, and tissue specimens (1 from each patient) underwent assay by PCR as well as bacteriological, histological, and cytological examination. We used two PCR reactions: in the first the complex-specific insertion sequence IS986/IS6110 was used to specifically detect DNA from Mycobacterium tuberculosis complex bacteria; in the second, conserved sequences of the mycobacterial groEL gene were used to detect DNA from mycobacteria other than M tuberculosis. The PCR was more sensitive than culture for diagnosis of tuberculosis. However, the false-positive PCR rate for M tuberculosis was 9%. M tuberculosis DNA was found in half the sarcoidosis patients, and non-tuberculosis mycobacterial DNA in a further 20%. The findings that a significant proportion of the sarcoidosis patients in this study have mycobacteria in their lungs and that most of these mycobacteria belong to M tuberculosis complex suggest an aetiological role for mycobacteria in sarcoidosis.


Mutant debrisoquine hydroxylation genes in Parkinson's disease. The frequency of fifteen genotypes of CYP2D6 (debrisoquine 4-hydroxylase) in 53 patients with Parkinson's disease was determined by the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analyses and compared with the findings in 72 healthy controls. The commonest mutant allele, CYP2D6B, was twice as frequent among patients as in controls, with an approximate relative risk ratio of 2.70 (95% confidence interval 1.14-6.41; p = 0.0063) for subjects homozygous or heterozygous for this allele.


Sensitivity of serological assays to identify blood donors with hepatitis C viraemia. Blood donors at high risk of hepatitis C virus (HCV) infection were tested for viraemia by the polymerase chain reaction (PCR). PCR results were accepted as positive only if reactive in 3 of 4 tests and if confirmed in an independent laboratory. The sera were also tested by 6 different assays to determine the ability of current serological assays to detect viraemic blood donors. Of 19 PCR-positive sera, only 13 (68%) were detected by the most sensitive of the serological assays. If these results are confirmed, automated PCR assays may be required for blood-donor screening to prevent transmission of HCV.


Variation in the quality of cardiopulmonary resuscitation. During instruction in basic cardiopulmonary resuscitation (CPR) skills, cardiac massage and mouth-to-mouth ventilation are applied without interruption for no longer than a few minutes. The aim of this study was to see if the quality of technique during the first 2 min of CPR reflects the resuscitators ability to perform CPR over a 15 min period. Assessments were done with a resuscitation mannequin from which recordings of several variables were made at 2, 5, 10, and 15 min after the start of CPR. 60 lay volunteers who had received CPR training were studied, and six variables that describe the quality of CPR technique were recorded and scored with a predefined scoring system. No deterioration in CPR skills was seen during 15 min. We conclude that the initial 2 min assessment reflects the resuscitators ability to perform CPR over a longer period.


Effects of self-help post-myocardial-infarction rehabilitation on psychological adjustment and use of health services. A home-based exercise programme has been found to be as useful as a hospital-based one in improving cardiovascular fitness after an acute myocardial infarction. To find out whether a comprehensive home-based programme would reduce psychological distress, 176 patients with an acute myocardial infarction were randomly allocated to a self-help rehabilitation programme based on a heart manual or to receive standard care plus a placebo package of information and informal counselling. Psychological adjustment, as assessed by the Hospital Anxiety and Depression Scale, was better in the rehabilitation group at 1 year. They also had significantly less contact with their general practitioners during the following year and significantly fewer were readmitted to hospital in the first 6 months. The improvement was greatest among patients who were clinically anxious or depressed at discharge from hospital. The cost-effectiveness of the home-based programme has yet to be compared with that of a hospital-based programme, but the findings of this study indicate that it might be worth offering such a package to all patients with acute myocardial infarction.


Protection against immune haemolytic disease of newborn infants by maternal monocyte-reactive IgG alloantibodies (anti-HLA-DR). The extent to which maternal anti-Rh(D) antibodies support lysis of erythrocytes by monocytes in the antibody-dependent cell-mediated cytotoxicity (ADCC) assay is closely correlated with the severity of Rh(D) haemolytic disease of the newborn infant (HDN). However, in some cases HDN is much milder than would be predicted from the ADCC value. We postulated that maternal ADCC-blocking alloantibodies against paternal antigens on monocytes can protect these infants against severe haemolysis. We studied 13 severely Rh(D)-alloimmunised mothers whose infants showed unexpectedly mild HDN (group I) and 14 women with similar ADCC values but whose infants had severe HDN (group II). 7 group-I women had monocyte-reactive IgG alloantibodies that inhibited lysis by paternal monocytes in the ADCC. No such antibodies were found in group II (p less than 0.01). In 6 of the 7 serum samples with monocyte-reactive antibodies, the antibodies had HLA-DR specificity. Our findings suggest that Rh(D)-positive children of some severely Rh(D)-alloimmunised women may be protected from severe HDN by maternal non-HLA-class-I, IgG alloantibodies against paternal monocyte blood-group antigens. These antibodies may inhibit the mononuclear phagocyte system of the fetus.


Clonal p53 mutation in primary cervical cancer: association with human-papillomavirus-negative tumours. Analyses of cancer cell lines and of anal cancers suggest an inverse correlation between infection with human papillomavirus (HPV) and somatic mutation of the p53 tumour-suppressor gene. We have investigated this association in primary cervical tumours. Tumour-tissue samples from 28 women with primary cancer of the cervix were analysed for presence of HPV sequences and for somatic mutations of the p53 gene. Southern blot analysis and the polymerase chain reaction (PCR) showed that 25 of the tumours contained HPV sequences; 20 were HPV16 positive and 5 HPV18 positive. 17 tumours subjected to restriction fragment length polymorphism analysis for the short arm of chromosome 17 showed no evidence of allelic deletion. Sequencing of the entire coding region of the p53 gene by asymmetric PCR detected heterozygous point mutations in only 3 HPV-negative tumours. By contrast, in 21 HPV-positive cancers the p53 sequence was wild-type throughout. Our data indicate that loss of wild-type p53 function is important in the pathology of cervical cancer and that in the absence of an HPV-encoded gene product that mediates loss of p53 function, somatic mutation of the gene is required. This pattern of p53 mutation may partly explain the apparently worse prognosis of HPV-negative cervical cancers.


Erythrocyte glutathione and tumour response to chemotherapy. There is much evidence that tumour glutathione (GSH) concentration is an important factor in resistance to cancer chemotherapy. Since measurement of tumour GSH would require an invasive procedure in every patient, we have tried to find out whether GSH concentrations in peripheral-blood erythrocytes are related to the response to chemotherapy and thus whether they reflect those in tumour cells. Erythrocyte GSH concentrations were measured by spectrophotometry in peripheral blood from 28 patients with advanced breast cancer and 40 patients with other tumours before and after treatment with various conventional chemotherapeutic regimens. The mean pretreatment GSH concentration was lower in patients who showed a complete or partial response to chemotherapy than in those with stable or progressive disease in both the breast-cancer group (8.69 [95% confidence interval 5.99-11.39] vs 2.32 [1.23-3.41] mumol/g haemoglobin; p less than 0.01) and the group with other tumours (5.94 [4.14-7.74] vs 2.83 [1.71-3.95] mumol/g; p less than 0.01). The correlation of erythrocyte GSH concentration with response rate suggests that this measurement may be helpful in prediction of response to therapy.


Cardiac effects of relaxin in rats.

Cardiac effects of relaxin in rats. Relaxin is usually considered to be a hormone of pregnancy, but porcine relaxin has been shown to increase heart rate in rats. We investigated the cardiac effects of synthetic human gene-2 relaxin (hRlx-2) in vitro in isolated rat atria. Synthetic hRlx-2 produced concentration-dependent positive chronotropic effects in spontaneously beating right atria (EC50 [concentration required to produce 50% of the maximal response] = 0.09 [SE 0.03] nmol/l) and concentration-dependent positive inotropic effects in electrically driven left atria (EC50 = 0.31 [0.02] nmol/l). The potency of hRlx-2 is greater than that of endothelin, angiotensin II, and (-)-isoprenaline in isolated rat atria. Relaxin has powerful chronotropic and inotropic effects on the heart that are probably mediated through a direct action on relaxin receptors.


Identical genetic locus for Baltic and Mediterranean myoclonus. Genetic linkage analysis shows that Baltic and Mediterranean myoclonus, two forms of progressive myoclonus epilepsy, are closely linked to marker D21S113 on the long arm of chromosome 21. Baltic and Mediterranean myoclonus are most probably due to mutations of the same gene.


De-novo mutation in hereditary motor and sensory neuropathy type I. Isolated cases of hereditary motor and sensory neuropathy type I (HMSN I, Charcot-Marie-Tooth disease type 1) have been thought to be most frequently autosomal recessive. We have found that a recently discovered duplication in chromosome 17, responsible for most cases of autosomal dominant HMSN I, is present as a de-novo mutation in 9 out of 10 sporadic patients. This finding has important implications for genetic counselling of isolated patients with HMSN I.


Individual quality of life in patients undergoing hip replacement. Quality of life (QoL) assessment is becoming increasingly important for measuring the impact of illnesses, diseases, and their treatment and for deciding priorities when allocating resources. We developed a novel method to measure QoL from the perspective of the individual patient. The schedule for the evaluation of individual quality of life (SEIQoL) was devised from the technique known as judgment analysis to measure patients' level of functioning in five self-nominated facets of life and the relative weight or importance attached to these areas. We applied this method, together with traditional measures of health status, in a prospective intervention study of 20 patients undergoing unilateral total hip-replacement surgery with six-month follow-up by comparison with matched, non-patient controls. Health status was significantly improved by hip replacement on the McMaster health index questionnaire (p less than 0.001) and the arthritis impact measurement scales (p less than 0.001). Individually measured QoL was significantly increased after surgery when measured by SEIQoL (p less than 0.02). The individual nature of QoL was reflected in the variety of life areas nominated as important by individual patients, the differences in relative weights attached to these areas, and the complex nature of the changes that occurred postoperatively. Our data not only highlight such individuality but also show that SEIQoL provides a means by which this can be assessed scientifically.


Randomised comparison of oral ofloxacin alone with combination of parenteral antibiotics in neutropenic febrile patients. Prompt treatment with empirical antibiotics in neutropenic febrile patients reduces morbidity and mortality. Most patients have been treated with parenteral combination antibiotics, but newer antibiotics with broad-spectrum bactericidal activity have made monotherapy feasible. Ofloxacin, a broad-spectrum fluoroquinolone, has the additional advantage that bactericidal concentrations can be achieved with oral administration. We have compared ofloxacin as an oral single agent with standard parenteral combination antibiotics for the management of neutropenic febrile patients in a prospective, randomised trial. Patients with severe neutropenia (absolute neutrophil count less than or equal to 0.5 x 10(9)/l), fever above 38 degrees C, and ability to take drugs by mouth were eligible for the study. After initial investigations, 60 patients were randomly assigned to oral ofloxacin 400 mg twice daily and 62 to parenteral combination antibiotic therapy (amikacin 15 mg/kg daily, plus, at various times in the trial, carbenicillin, cloxacillin, or piperacillin). Patients were examined 72 h and 7 days after the start of treatment and when neutropenia resolved. 24 (40%) ofloxacin-treated and 26 (42%) combination-treated patients had pyrexia of unknown origin (PUO). In both treatment groups, the treatment success rate was higher for such patients than for those with clinically or microbiologically documented infections (92% vs 67% [p less than 0.05] for ofloxacin; 85% vs 64% for combination). There were no significant differences in success rates of ofloxacin and combination treatment for these subgroups or overall (77% vs 73%). Patients with neutropenia for less than 1 week had better responses to both treatments than patients with longer-lasting neutropenia. There were 4 (7%) deaths in the ofloxacin group and 6 (10%) in the combination group. Both regimens were well tolerated. We conclude that oral single-agent ofloxacin is as effective as parenteral combination antibiotic therapy in neutropenic febrile patients, especially those expected to have short durations of neutropenia.


Effect of the anticonvulsant U-54494A on cortical neuron excitability: comparison to the kappa agonist U-50488H. U-54494A, a 1,2-diamine anticonvulsant, and U-50488H, a structurally related agonist for opiate kappa receptors, were tested for effects on spontaneous and glutamate-evoked firing rates in cerebral cortex of urethane-anesthetized male Sprague-Dawley rats. Iontophoretic application of 1,2-diamines, glutamate diethyl ether (GDEE), or procaine depressed spontaneous and amino acid-induced firing of cortical neurones. With continued ejection of 1,2-diamines or procaine, firing was silenced completely, but GDEE could maintain a partial suppression. A rapid rebound of excitation followed cessation of procaine ejections, but not of other agents. Procaine, but not U-54494A, blocked axonal conduction of rabbit sciatic nerve. Intravenous U-54494A and U-50488H significantly depressed spontaneous firing rates of cortical neurones, but only the U-50488H effects were antagonized by naloxone. It is concluded that U-54494A inhibits neuronal excitability by a mechanism independent of the analgesic kappa receptor. Biochemical and physiological studies have demonstrated that U-54494A and the kappa opioid agonist U-50488H (a structurally related diamine) (1) have anticonvulsant activity (2, 3). U-54494A lacks kappa analgesic and sedative properties, and it has been suggested that the mechanism of action of this compound may be mediated by a subtype of kappa opioid receptor (3). The effects of kappa analgesics on neuronal firing in nociceptive pathways have been described (4, 5). However, no previous electrophysiological studies on U-54494A have been done. Since U-54494A antagonizes amino acid-induced seizures (3), the interactions of this compound with glutamate are of interest. In the present study, the antagonist efficacies of U-54494A and U-50488H for inhibiting spontaneous and 1-glutamate stimulated neurons of the rat prefrontal cerebral cortex were assessed after i.v. and microiontophoretic administration of the compounds. Effects observed with these routes of administration allow the observation of neuronal changes occurring immediately after administration and take advantage of the high temporal resolution provided by the electrophysiological recording techniques of single cells. A preliminary account of portions of this work have been previously disclosed (6).


AIDS--an autoimmune model.

AIDS--an autoimmune model. In AIDS a complementary interface between the HIV virus and the CD4 molecule of the T4 lymphocyte suggest a possible cause of immune self-recognition. Because of this complementarity, an anti-idiotypic immune response to the CD4 attachment area of HIV should result in an autoimmune reaction to CD4 positive lymphocytes. Experimental demonstration of such an immune recognition model by autoreactive lymphocytes is presented and a hypothetical immune response unit is suggested.


Preferential desensitization of beta- versus alpha 2-adrenergic receptors accelerates loss of response to norepinephrine in primary glial cultures. The effect of norepinephrine (NE) on cAMP accumulation in primary glial cultures is mediated by two functionally opposing receptor subtypes. beta-Adrenergic receptor activation increases cAMP formation, whereas simultaneous alpha 2-adrenergic receptor activation partially inhibits this effect. We compared desensitization of these two responses during exposure to selective agonists or NE. Pretreatment with the beta-selective agonist isoproterenol (ISO) decreased responses to ISO, ISO plus the alpha 2-selective agonist UK 14,304 (UK), and NE. However, ISO plus UK and NE responses decreased more, relative to their control values, than did responses to ISO alone. Pretreatment with UK increased cAMP responses to both ISO and forskolin (sensitization), with little effect on alpha 2-mediated inhibition of these responses. Pretreatment with NE caused effects similar to those of both ISO and UK pretreatment. NE pretreatment decreased responses to ISO, ISO plus UK, and NE, sensitized responses to forskolin, and had little effect on alpha 2-mediated inhibition. Thus, chronic agonist exposure desensitizes beta-adrenergic receptors more rapidly and at much lower concentrations than alpha 2-adrenergic receptors in these cultures. The continuing alpha 2 inhibition during diminishing beta stimulation functionally accelerates the loss of the NE response.


Identification of a single amino acid residue responsible for the binding of a class of beta-adrenergic receptor antagonists to 5-hydroxytryptamine1A receptors. The 5-hydroxytryptamine1A (5-HT1A) receptor can bind certain beta-adrenergic receptor antagonists, such as pindolol, with high affinity. Such pharmacological cross-reactivity suggests a structural similarity in the ligand binding site between the two receptors. To identify this structural entity, we mutated Asn385 in the seventh transmembrane domain of the human 5-HT1A receptor, based on the observation that this residue is conserved in all 5-HT1A and beta-adrenergic receptors of different species but is absent in all other cloned guanine nucleotide-binding protein-coupled receptors. This single point mutation (Asn385 to valine) causes a highly selective decrease in the affinity of pindolol and other aryloxyalkylamines for the mutant receptor (about 100-fold), while producing only minor changes in the binding of other 5-HT agonists and antagonists. The results provide direct evidence that Asn385 is responsible for the high affinity interaction between 5-HT1A receptors and aryloxyalkylamine beta-adrenergic antagonists but is not required for the binding of other chemical classes of ligands.


L-proline activates glutamate and glycine receptors in cultured rat dorsal horn neurons. The pharmacological actions of L-proline on excitatory and inhibitory amino acid receptors have been characterized under voltage-clamp conditions, using cultured dissociated neurons from the dorsal horn of the rat spinal cord. At a holding potential of -62 mV, millimolar concentrations of L-proline elicited an inward current that was partially antagonized by D-(-)-2-amino-5-phosphonopentanoic acid (APV), 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), and strychnine and was virtually abolished (97% block) by a combination of all three antagonists. Currents evoked by D-proline were abolished by strychnine alone. APV-, CNQX-, and strychnine-sensitive components of L-proline-evoked currents were isolated using various combinations of the three antagonists. These currents were identical to currents elicited by N-methyl-D-aspartate (NMDA), kainate, and glycine, respectively, with respect to antagonist specificity, reversal potential, and ionic permeability. The APV- and strychnine-sensitive currents also showed a time dependence similar to that of the currents elicited by NMDA and glycine. EC50 values could not be calculated, because the response did not saturate within the tested range of L-proline concentrations (0.3-50 mM). Estimates of relative potency were obtained, however, by comparison with responses elicited by selective agonists. The APV-sensitive, CNQX-sensitive, and strychnine-sensitive currents evoked by 10 mM L-proline were comparable in size to currents elicited by 15 microM NMDA, 5 microM kainate, and 30 microM glycine, respectively. L-Proline was found to elicit an increase in intracellular [Ca2+] that was dependent upon Ca2+ entry into the cell. These Ca2+ responses were enhanced by strychnine and partially antagonized by APV, CNQX, or Mg2+. Our results using dorsal horn neurons grown in culture indicate that L-proline is a weak agonist at strychnine-sensitive glycine receptors and at both NMDA and non-NMDA glutamate receptors. These observations should help in interpreting the confusing array of L-proline actions that have been described using more intact nervous system preparations. Furthermore, the ability of L-proline to stimulate Ca2+ entry after activation of excitatory amino acid receptors implicates L-proline as a potential endogenous excitotoxin.


Identification of separate determinants on the thyrotropin receptor reactive with Graves' thyroid-stimulating antibodies and with thyroid-stimulating blocking antibodies in idiopathic myxedema: these determinants have no homologous sequence on gonadotropin receptors. Deletions, substitutions, or mutations of the rat TSH receptor extracellular domain between residues 20 and 107 (all residue numbers are determined by counting from the methionine start site) have been made by site-directed mutagenesis of receptor cDNA. After transfection in Cos-7 cells, constructs were evaluated for their ability to bind [125I]TSH or respond to TSH and thyroid-stimulating antibodies (TSAbs) from Graves' patients in assays measuring cAMP levels of the transfected cells. Assay results were compared to results from Cos-7 cells transfected with wild-type receptor constructs or vector alone. We identify threonine-40 as a TSAb-specific site whose mutation to asparagine, but not alanine, reduces TSAb activity 10-fold, but only minimally affects TSH-increased cAMP levels. We show that thyroid-stimulating blocking antibodies (TSBAbs), which block TSH or TSAb activity and are found in hypothyroid patients with idiopathic myxedema, continue to inhibit TSH-stimulated cAMP levels when threonine-40 is mutated to asparagine or alanine, suggesting that TSBAbs interact with different TSH receptor epitopes than the TSAb autoantibodies in Graves' patients. This is confirmed by the demonstration that these TSBAbs interact with high affinity TSH-binding sites previously identified at tyrosine-385 or at residues 295-306 of the extracellular domain of the TSH receptor. This is evidenced by a loss in the ability of TSBAbs to inhibit TSAb activity when these residues are mutated or deleted, respectively. Since the TSAb and TSBAb epitopes are in regions of the extracellular domain of the TSH receptor that have no homology in gonadotropin receptors, these data explain at least in part the organ-specific nature of TSH receptor autoantibodies in autoimmune thyroid disease. Data are additionally provided which indicate that residues 30-37 and 42-45, which flank the TSAb epitope at threonine-40, appear to be ligand interaction sites more important for high affinity TSH binding than for the ability of TSH to increase cAMP levels and that cysteine-41 is critical for TSH receptor conformation and expression on the surface of the cell. Thus, despite unchanged maximal values for TSH-increased cAMP levels, substitution of residues 42-45 or deletion of residues 30-37 results in receptors, which, by comparison to wild-type constructs, exhibit significantly worsened Kd values for TSH binding than EC50 values for TSH- or TSAb-increased cAMP activity.(ABSTRACT TRUNCATED AT 400 WORDS)


Successive action of DnaK, DnaJ and GroEL along the pathway of chaperone-mediated protein folding. The main stress proteins of Escherichia coli function in an ordered protein-folding reaction. DnaK (heat-shock protein 70) recognizes the folding polypeptide as an extended chain and cooperates with DnaJ in stabilizing an intermediate conformational state lacking ordered tertiary structure. Dependent on GrpE and ATP hydrolysis, the protein is then transferred to GroEL (heat-shock protein 60) which acts catalytically in the production of the native state. This sequential mechanism of chaperone action may represent an important pathway for the folding of newly synthesized polypeptides.


Alpha 2-adrenoceptor modulation of rat ventral hippocampal 5-hydroxytryptamine release in vivo. The putative existence of a functional alpha 2-adrenoceptor-mediated modulation of 5-HT release in vivo from serotonergic neuronal terminals in the ventral hippocampus was investigated using intracerebral microdialysis in chloral hydrate-anaesthetised rats. The alpha 2-adrenoceptor agonist clonidine (0.01-0.3 mg/kg, SC) dose-dependently decreased the 5-HT output. The response to clonidine was antagonized by systemic or local administration of the alpha 2-adrenoceptor antagonist idazoxan (0.1 mg/kg, SC, or 10 mumol/l, via the dialysis perfusion medium). Similarly, the 5-HT release-suppressing response to the thiazole alpha 2-adrenoceptor agonist jingsongling (0.1 mg/kg, SC) was blocked by idazoxan (0.1 mg/kg, SC). The mixed beta-adrenoceptor/5-HT1 receptor antagonist pindolol (8.0 mg/kg, SC) did not affect the clonidine-induced reduction of 5-HT release. Tyrosine hydroxylase inhibition by means of alpha-methyl-para-tyrosine (alpha-MT; 250 mg/kg, IP) caused a drastic reduction (greater than 80%) in dialysate 3,4-dihydroxyphenyl acetic acid (DOPAC) output but did not affect the 5-HT output per se over 3 h post-injection. Nor did the alpha-MT pretreatment prevent, but instead significantly enhanced, the 5-HT release-suppressing effect of clonidine. The results demonstrate that the release of 5-HT from serotonergic nerve terminals in rat ventral hippocampus in vivo is modulated by alpha 2-adrenoceptors, probably both by heteroreceptors on the axon terminals of the serotonergic neurones and by other alpha 2-adrenoceptor sites situated pre- and/or postsynaptic to the noradrenergic terminals. Our results also suggest that while functionally operative, these sites may receive little physiological tone, at least in chloral hydrate-anaesthetised rats.


The effect of intrastriatal application of directly and indirectly acting dopamine agonists and antagonists on the in vivo release of acetylcholine measured by brain microdialysis. The importance of the post-surgery interval. The effect of intrastriatal application of D-1, D-2 and indirect dopaminergic drugs on the release of striatal acetylcholine as a function of the post-implantation intervals was studied using in vivo microdialysis. The dopamine D-2 agonists LY 171555 and (-)N0437 inhibited the release of striatal acetylcholine to 40% of control values 16-24 h after implantation of the dialysis cannula. When LY 171555 was infused 40-48 h after implantation of the dialysis cannula, the response was attenuated to 20% of control values. Meanwhile, the effectiveness of infusions of the antagonists (-)sulpiride and haloperidol was augmented from a non significant effect at 16-24 h to a 150% increase 40-48 h after implantation of the cannula. Infusions of the dopamine releasing agent amphetamine or the dopamine uptake inhibitor nomifensine resulted in a dose-dependent increase in the overflow of dopamine. Not until a sevenfold increase in the level of dopamine was seen, the release of acetylcholine was significantly affected. This hyporesponsiveness of the striatal cholinergic interneurons to endogenous dopamine could not be attributed to dopamine D-1 receptor activation, since no effects on striatal acetylcholine release were found by intrastriatal infusions of the selective D-1 agonist CY 208-243 or the selective D-1 antagonist SCH 23390. The results indicate that dopamine D-2 receptors are involved in the regulation of striatal acetylcholine release and that these receptors are tonically occupied by endogenous dopamine under the present experimental conditions 40-48 h after probe implantation.(ABSTRACT TRUNCATED AT 250 WORDS)


Evidence for verapamil-induced functional inhibition of noradrenergic neurotransmission in vivo. Contractions of the cat nictitating membrane have been used to explore the effects of calcium channel blockers on neurotransmission in vivo, by comparing the effects of verapamil and nifedipine on contractions of nictitating membrane following either electrical stimulation of the superior cervical ganglion or intravenous injection of the alpha-adrenoceptor agonist phenylephrine. Verapamil (0.3, 0.6 and 1.2 mg/kg, iv) produced a dose related and reversible inhibition of stimulation induced contractions but did not affect phenylephrine responses of nictitating membrane. Intravenous nifedipine (10, 20 and 40 micrograms/kg) produced inconsistent effects on both stimulation- and phenylephrine-induced contractions of the nictitating membrane. Thus only verapamil appears to selectively affect noradrenergic neurotransmission in this model, possibly by altering the neurotransmitter release from the terminals innervating the nictitating membrane in the cat.


Expression of the intercellular adhesion molecule-1 (ICAM-1) in human renal allografts and cultured human tubular cells. The in vivo distribution of the intercellular adhesion molecule ICAM-1 was investigated in renal tissue specimens obtained from 17 renal allotransplanted patients, nine normal kidneys (controls), seven native kidneys, nine patients with mesangioproliferative glomerulonephritis, and nine patients with active extracapillary glomerulonephritis. Biopsies from patients with signs of acute rejection showed a significant increase in ICAM-1 expression in the tubular epithelium (P less than 0.05). In normal kidneys (controls) ICAM-1 expression was found in endothelial cells; additional expression in the tubular epithelial cells was induced in patients with extracapillary glomerulonephritis. The in vitro expression of ICAM-1 was examined in cultured human tubular cells after stimulation with gamma-interferon and interleukin-1, treatment with cyclosporin and/or verapamil and coculture with allogenic mononuclear cells. An increased ICAM-1 expression was demonstrated by coculture with allogenic mononuclear cells and after stimulation with gamma-interferon and/or interleukin-1. Cyclosporin or verapamil induced no changes. Our results give support to the hypothesis that ICAM-1 upregulation is important in immune interactions such as allograft rejection. Furthermore, the in vitro model indicates that ICAM-1 expression is regulated by gamma-interferon and interleukin-1 produced by activated T lymphocytes and macrophages.


Analysis of gene amplification in archival tissue by differential polymerase chain reaction. Oncogene amplification is found in many human tumors, and its detection may have important prognostic value. However, analysis of gene amplification may be hampered by inadequate tissue or poor DNA quality. We have previously described a polymerase chain reaction (PCR)-based procedure called differential PCR that can detect variations in gene dosage using miniscule amounts of tumor DNA [Frye, R.A., Benz, C.C. & Liu, E. (1989). Oncogene, 4, 1153-1157]. We now report the optimization of this technique for the analysis of oncogene amplification in paraffin-embedded archival tissues. We find that differential PCR is able to detect amplification of the HER2 (c-erbB-2) and the epidermal growth factor receptor (EGFR) genes and can be used to arrive at a semiquantitative estimate of gene dosage. Furthermore, our approach can determine gene amplification in samples in which the DNA is significantly degraded. Using differential PCR on paraffin-embedded tissues from cases previously investigated by standard DNA extraction and dot-blot procedures, good correlation between the two methods was found. Approaches are described to overcome technical problems posed by factors that affect the differential PCR, including the method of DNA extraction and extreme fragmentation of the DNA (less than 200 base pairs). Furthermore, the resulting analytical algorithm reported herein has proved effective in detecting oncogene amplification in archival breast cancer specimens from standard pathology laboratories. Thus, differential PCR will be particularly helpful in the analysis of tumor specimens that are archived, small in size or rare in occurrence.


The HER2 (c-erbB-2) oncogene is frequently amplified in in situ carcinomas of the breast. Amplification and overexpression of the HER2 (c-erbB-2) oncogene was assessed in paraffin-embedded specimens from 27 in situ carcinomas of the breast and from 122 stage II breast cancers. Gene amplification detected in these archival tissues by differential polymerase chain reaction (PCR) was found in 48% of in situ carcinomas and in 21% of stage II lesions (chi 2 = 7.62, p less than or equal to 0.01). In addition, the level of gene amplification correlated with the level of HER2 oncoprotein expression as measured by immunohistochemistry for both in situ cancers (p less than or equal to 0.025) and stage II cancers (p less than or equal to 0.0005). This high incidence of HER2 gene amplification with accompanying overexpression in non-invasive breast tumors suggests that perturbations of the HER2 oncogene are among the earliest and most common genetic lesions in human breast cancer.


p53 mutations in spontaneously immortalized 3T12 but not 3T3 mouse embryo cells. We have asked whether p53 mutations are involved in the process of spontaneous immortalization of mouse embryo cells. Cells from Swiss mouse embryos were used to prepare 3T3 and 3T12 lines according to the protocol of Todaro & Green [(1963). J. Cell Biol., 17, 299-313]. After the cells emerged from crisis, p53 sequences were amplified by polymerase chain reaction (PCR) from both RNA and DNA. The sequence of the aggregated cDNA from each of six 3T3 lines showed no evidence of mutation. PCR-amplified p53 cDNA from two 3T3 lines was cloned, and individual clones in M13mp19 were partially sequenced. One cell ine showed a single, non-coding nucleotide change in 2/8 independent clones. Nine cDNA clones from the second 3T3 lines were sequenced, and no single nucleotide changes appeared more than once. The mutations which appeared only once were not detected in clones of genomic DNA. Since these apparent mutations are probably reverse transcriptase or Taq polymerase errors, we conclude that both the 3T3 lines contained only wild-type p53. In two out of three independent 3T12 lines however, missense mutations were readily observed in the aggregate cDNA sequence. Restriction fragment length polymorphism and Southern blot analyses of the genomic DNA indicated that these cells were homozygous for the mutations. The p53 protein molecules in four cell lines were analysed by immunoprecipitation: one 3T12 line showed the pattern of antibody reactivity characteristic of some p53 mutants, while the others displayed the wild-type pattern. We conclude that p53 mutations arise and are strongly selected for during immortalization according to the 3T12 but not the 3T3 protocol.