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Biomedical subjects

L Wilson

Publications and source records attributed to L Wilson.

At least 217 records · Page 12Linked to original sources
PubMed1993

Learned helplessness and in vivo hippocampal norepinephrine release.

Hippocampal norepinephrine release was measured using in vivo microdialysis in rats before and after exposure to inescapable tail shock stress and after testing for learned helplessness. Rats that did not develop learned helplessness after stress had higher basal norepinephrine release after stress than rats developing learned helplessness or than control rats. After the shuttlebox test for learned helplessness, K(+)-stimulated norepinephrine release was lower in learned helpless than in nonhelpless or control rats. These results confirm an important role for the hippocampal noradrenergic system in differential behavioral responses to stress.

Animals↗
PubMed1993

The DNA sequence of the equine herpesvirus 4 gene encoding glycoprotein gp17/18, the homologue of herpes simplex virus glycoprotein gD.

The nucleotide sequence of the gene to the left of the gI gene of equine herpesvirus 4 (EHV-4) was determined. The gene encodes a peptide of 402 amino acids with an unprocessed M(r) of 45,323. The predicted polypeptide has several features of a glycoprotein including a hydrophobic signal sequence, a membrane spanning domain and four potential N-linked glycosylation sites within the proposed external domain. The predicted amino acid sequence of EHV-4 gD shows 83% identity with that of equine herpesvirus 1 gD. Conservation of the tertiary structure is suggested by the alignment of six cysteine residues with those of the gD of six other alphaherpesviruses. Screening a lambda gt11/EHV-4 expression library with monoclonal antibodies against several of the most abundant EHV-4 glycoproteins unequivocally identified the protein encoded by the EHV-4 gD gene as gp17/18.

Amino Acid Sequence↗
PubMed1993

Leukocyte CD18 monoclonal antibody worsens endotoxemia and cardiovascular injury in canines with septic shock.

We investigated the effects of a murine monoclonal antibody directed against the canine leukocyte CD11/18 adhesion complex (MAb R15.7) in a canine model of septic shock. Awake 2-yr-old purpose-bred beagles were studied 7 days before and 1, 2, 4, and 10 days after intraperitoneal placement of an Escherichia coli-infected fibrin clot. Starting 12 h before clot placement, animals received 0.5-1 mg/kg iv every 12 h (4 doses total) of either MAb R15.7 (MAb group, n = 8) or, as controls, murine serum protein (n = 8). After infected clot placement, all animals received antibiotic (ceftriaxne, 100 mg.kg-1.day-1 for 4 days). Two of eight control animals and four of eight MAb animals died (P = 0.4). During the first 8 h after clot placement, MAb animals, compared with control animals, had greater (P < 0.06) increases in serum endotoxin levels and higher (P < 0.05) neutrophil counts. Day 1 after clot placement, MAb animals, compared with control animals, had decreased (P < 0.05) central venous pressure and arterial pH and increased (P < 0.05) arterial lactate. Day 2 after clot placement, MAb animals, compared with control animals, had decreased (P < 0.05) cardiac index and mean arterial pressure. In summary, MAb R15.7, although associated with increased neutrophil counts, worsened serum endotoxemia, acidosis, and cardiovascular function in this canine model of septic shock. These data suggest that in septic shock, antibody directed against this leukocyte membrane protein complex may be harmful, possibly via impairment of normal leukocyte function.

Acid-Base Equilibrium↗
PubMed1993

Natural human antibodies to synthetic peptide autoantigens: correlations with age and autoimmune disease.

Clinically healthy humans as well as patients suffering from various autoimmune diseases produce natural antibodies against a variety of self-components. Such antibodies have been proposed to carry out a physiologic role in maintaining the integrity of self, as well as potentially destructive roles in the generation of autoimmune diseases. Because human autoantigens, particularly membrane proteins, are usually present in extremely small amounts, it is generally impossible to obtain enough to carry out a detailed characterization of the antibodies or the antigenic determinants recognized. To circumvent this difficulty, we developed synthetic autoantigens predicted from the gene sequence of two functionally critical membrane proteins; the band 3 anion transport protein which is found on all cells, and the T-cell receptor (beta chain) which is the antigen-specific receptor on thymus-derived lymphocytes. We have investigated the natural human IgM and IgG antibody responses to peptides selected on the basis of predicted molecular surface exposure and previously known antigenicity, and correlate levels of binding with changes in age and by comparison with autoimmune diseases. We report that the IgM response to synthetic autoantigens tends to be higher than that of IgG molecules, but significant IgG binding occurs to some peptides. This situation is particularly noticeable in comparison of rheumatoid arthritis patients with normal individuals. Distinct peptide portions of individual molecules are recognized differently by the autochthonous immune system as manifested by age dependence of the response and differential levels of IgM and IgG activity. The synthetic autoantigens that tend to generate the highest amounts of natural antibody are those that are either exposed on the surface of the cell (band 3 peptides) or are exposed in the predicted 3-dimensional folding of the molecule (T-cell receptor beta peptides). Rheumatoid arthritis patients tend to give higher IgM reactivities to both band 3 and Tcr beta peptides than do normals, with this effect being less pronounced in the distinct autoimmune disease systemic lupus erythematosus. Studies of normal humans ranging in age from 20 to 90 years suggest two major patterns for the IgM natural antibody response to synthetic peptides giving high response. The first is that the level of IgM reactivity is high early in life and remains high throughout. The second pattern is one in which the reaction is high in younger individuals, but diminishes substantially in the latter decades of life.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1993

An alternative Pit-1 RNA splicing product reveals modular binding and nonmodular transcriptional activities of the POU-specific domain.

We have identified a form of the pituitary-specific POU protein Pit-1 that results from deletion of the POU-specific (POUs) domain by alternative RNA splicing. This natural variant of Pit-1 (called delta 4Pit-1) has revealed several aspects of the function of the POUs domain. The delta 4Pit-1 protein was characterized using a delta 4Pit-1-specific antiserum. Further, selection assays of random oligonucleotide pools identified binding site preferences for both wild type and delta 4Pit-1. Methylation interference, copper phenanthrolene, and missing contact analyses were used to compare the binding characteristics of the two forms of Pit-1 on a selected site. DNA binding affinity assays on several DNA elements revealed that the POUs domain contains a modular DNA binding activity affecting the DNA binding affinity of the entire POU domain on some, but not on other, DNA sites. Functional analysis on such DNA elements has revealed that the POUs domain is an essential, but nonmodular, component of the Pit-1 trans-activation domain dependent on its natural context within the Pit-1 protein.

Amino Acid Sequence↗
PubMed1993

Mitotic block in HeLa cells by vinblastine: ultrastructural changes in kinetochore-microtubule attachment and in centrosomes.

Previous work from this laboratory has indicated that very low concentrations of vinblastine block HeLa cells at mitosis in the presence of a full complement of microtubules and without major disruption of spindle organization. In the present study we analyzed the structural organization of mitotic spindle microtubules, chromosomes and centrosomes by electron microscopy after incubating HeLa cells for one cell cycle with 2 nM vinblastine. We found that mitotic block of HeLa cells by vinblastine was associated with alterations of the fine structure of the spindle that were subtle but profound in their apparent consequences. The cell cycle was blocked in a stage that resembled prometaphase or metaphase; chromosomes had not undergone anaphase segregation. Neither the structure of the microtubules nor the structure of the kinetochores was detectably altered by the drug. However, the number of microtubules attached to kinetochores was decreased significantly. In addition, the centrosomes were altered; the normal close association of mother and daughter centriole was lost, numerous membranous vesicles were found in the centrosomal region, and many centrioles exhibited abnormal ultrastructure and had microtubules coursing through their interiors. These findings are consistent with our previous results and indicate that inhibition of the polymerization dynamics of mitotic spindle microtubules and perhaps of centriole microtubules, rather than microtubule depolymerization, is responsible for the mitotic inhibition by vinblastine.

Cell Death↗
PubMed1993

Sexual fears are increasing.

This study compared scores from three samples of college students (N = 810) on the Sexual Aversion Scale, a measure of sexual anxiety based on DSM-III-R criteria for diagnosing sexual aversion disorder. Measurements were taken in 1988, 1991, and 1992. There was a significant increase in sexual anxiety during this period, most of it attributable to fear of acquiring AIDS. Although the women reported more sexual anxiety than the men over-all, there was no difference on fear of AIDS. These findings could foreshadow an increase in sexual dysfunctions and desire disorders.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Accuracy and reliability of 'specialized' physical therapists in auscultating tape-recorded lung sounds.

This study investigated the accuracy and inter-rater reliability of 'specialized' physical therapists in the auscultation of tape-recorded lung sounds. In addition, a correlation was investigated between accuracy of interpretation and the number of years of specialization in the field of cardiorespiratory physical therapy. This research follows an earlier study which investigated the accuracy and inter-rater reliability of auscultating tape-recorded lung sounds in a 'non-specialized' cohort of physical therapists. The subjects were 26 'specialized' cardiorespiratory physical therapists working in acute urban teaching hospitals. These individuals were required to have been practising currently and exclusively for at least one year in the area of cardiorespiratory physical therapy. Participants listened with a stethoscope to five different sounds and identified them from a standardized list of terms. One of three tapes with the same lung sounds in different order was randomly selected for each physical therapist. The percentage of correct answers for all subjects was calculated. An accurate response in the detection of lung sounds was arbitrarily defined as a percentage of correct answers of 70% or greater. The difference between the pooled correct response rate of 50% and the arbitrarily set value of 70% was statistically significant (z = 2.23, p < 0.05), indicating that the 'specialized' physical therapists were not accurate in identifying lung sounds. There was no relationship evident between the accuracy and the number of years of cardiorespiratory 'specialization' (r = 0.08). Analysis of inter-rater reliability revealed 'fair agreement' (kappa = 0.26) among subjects. These results were similar to those found in the previous study.(ABSTRACT TRUNCATED AT 250 WORDS)

Auscultation↗
PubMed1993

Coexistent anti-neutrophil cytoplasmic antibody and antiglomerular basement membrane antibody associated disease = report of six cases.

From a series of 95 patients biopsied for rapidly progressive glomerulonephritis, twelve patients were identified with anti-glomerular basement membrane-mediated renal disease who were also tested for antineutrophil cytoplasmic antibody (ANCA). Six patients had both anti-glomerular basement membrane and ANCA antibodies. Three of the latter six patients had significant extrarenal disease, including severe hemoptysis, while the remaining three patients had only renal disease. The three patients with extrarenal disease had either a myeloperoxidase-positive perinuclear-ANCA (two patients) or a proteinase-3-positive cytoplasmic-ANCA (one patient). Two patients with renal disease alone had a myeloperoxidase-negative and proteinase-3-negative perinuclear-ANCA, and one patient had a proteinase-positive cytoplasmic-ANCA. Renal biopsy in all six patients showed a severe necrotizing and crescentic glomerulonephritis involving 94 to 100% of glomeruli. Renal arteritis was also noted in one perinuclear-ANCA patient. Despite aggressive therapy with steroids, cyclophosphamide, and plasma exchange, two of the six double-antibody patients died and four are on dialysis. We conclude that ANCA is commonly present in anti-glomerular basement membrane-associated disease and believe that this observation may have implications in the serologic evaluation of ANCA- and anti-glomerular basement membrane-positive patients.

Adult↗
PubMed1993

A large, dominant pedigree of atrioventricular septal defect (AVSD): exclusion from the Down syndrome critical region on chromosome 21.

We describe a large pedigree of individuals with autosomal dominant atrioventricular septal defect (AVSD). The pedigree includes affected individuals and individuals who have transmitted the defect but are not clinically affected. AVSDs are a rare congenital heart malformation that occurs as only 2.8% of isolated cardiac lesions. They are the predominant heart defect in children with Down syndrome, making chromosome 21 a candidate for genes involved in atrioventricular septal development. We have carried out a linkage study in the pedigree by using 10 simple-sequence polymorphisms from chromosome 21. Multipoint linkage analysis gives lod scores of less than -2 for the region of trisomy 21 associated with heart defects, which excludes a locus within this region as the cause of the defect in this family.

Adult↗
PubMed1993

Plasma gamma-aminobutyric acid (GABA) is low in alcoholics.

Plasma levels of gamma-aminobutyric acid (GABA) were measured in male alcoholics on admission to inpatient treatment and at discharge after 3 to 4 weeks of abstinence. Free plasma GABA at discharge was significantly lower in alcoholics than in control subjects and specifically identified a subset of 35 percent of the alcoholic patients with levels below the normal range. However, levels of free plasma GABA in recently detoxified alcoholics on admission were not different from those of controls and had a significant positive correlation with liver enzymes and mean corpuscular volume. These data are compatible with a GABA deficit theory of alcoholism in a subset of alcoholics.

Adult↗
PubMed1992

Tempol, a stable free radical, is a novel murine radiation protector.

Nitroxide compounds are stable free radicals which were previously investigated as hypoxic cell radiosensitizers. The stable nitroxide 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (Tempol) has recently been shown to protect aerated cells in culture against superoxide generated from hypoxanthine/xanthine oxidase, hydrogen peroxide, and radiation-induced cytotoxicity and to modestly sensitive hypoxic cultured cells. To extend these observations from the cellular level to the whole animal, the toxicity, pharmacology, and in vivo radioprotective effects of Tempol were studied in C3H mice. The maximum tolerated dose of Tempol administered i.p. was found to be 275 mg/kg, which resulted in maximal Tempol levels in whole blood 5-10 min after injection. Mice were exposed to whole-body radiation in the absence or presence of injected Tempol (275 mg/kg) 5-10 min after administration. Tempol treatment provided significant radioprotection (P less than 0.0001); the dose of radiation at which 50% of Tempol-treated mice die at 30 days was 9.97 Gy, versus 7.84 Gy for control mice. Tempol represents a new class of in vivo, non-sulfur-containing radiation protectors. Given the potential for hypoxic radiosensitization and aerobic cell radioprotection, Temporal or other analogues may have potential therapeutic application.

Animals↗
PubMed1992

C. elegans unc-4 gene encodes a homeodomain protein that determines the pattern of synaptic input to specific motor neurons.

The creation of neural circuits depends on the formation of synapses between specific sets of neurons. Little is known, however, of the molecular mechanisms governing synaptic choice. A mutation in the unc-4 gene alters the pattern of synaptic input to one class of motor neurons in the Caenorhabditis elegans ventral nerve cord. In unc-4(e120), the presynaptic partners of VA motor neurons are replaced with interneurons appropriate to motor neurons of the VB class. This change in neural specificity is not accompanied by any detectable effects on neuronal morphology or process extension. We show that the absence of a functional unc-4 gene product accounts for the mutant phenotype. The unc-4 gene encodes a homeodomain protein and thus is likely to function as a transcription factor. The limited effect of the unc-4 null mutation on cell fate may mean that unc-4 regulates the expression of a small number of target genes and that the products of these genes are directly involved in the choice of synaptic partners.

Alleles↗
PubMed1992

Mechanism of inhibition of microtubule polymerization by colchicine: inhibitory potencies of unliganded colchicine and tubulin-colchicine complexes.

The tubulin-colchicine binding reaction appears to involve a number of intermediate steps beginning with rapid formation of a transient preequilibrium complex that is followed by one or more slow steps in which conformational changes in tubulin and colchicine lead to formation of a poorly reversible final-state complex. In the present study, we investigated the relative ability of unliganded colchicine and preformed final-stage tubulin-colchicine complex to incorporate at microtubule ends and to inhibit addition of tubulin at the net assembly ends of bovine brain microtubules in vitro. Addition of 0.1 microM final-stage tubulin-colchicine complex to suspensions of microtubules at polymer-mass steady-state resulted in rapid incorporation of one to two molecules of tubulin-colchicine complex per microtubule net assembly end concomitant with approximately 50-60% inhibition of tubulin addition. Incorporation of colchicine-tubulin complex continued slowly with time, without significant additional change in the rate of tubulin addition. In contrast, addition of unliganded colchicine to microtubule suspensions resulted in incorporation of small numbers of colchicine molecules at microtubule ends and inhibition of tubulin addition only after periods of time that varied from several minutes to approximately 20 min depending upon the concentration of colchicine. Inhibition of tubulin addition beginning with unliganded colchicine increased slowly with time, concomitant with increases in the concentration of final-state tubulin-colchicine complex and the amount of colchicine bound per microtubule end. The results indicate that inhibition of tubulin incorporation at microtubule ends is caused by colchicine-liganded tubulin in the form of a final-state complex.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Microtubule protein ADP-ribosylation in vitro leads to assembly inhibition and rapid depolymerization.

Bovine brain microtubule protein, containing both tubulin and microtubule-associated proteins, undergoes ADP-ribosylation in the presence of [14C]NAD+ and a turkey erythrocyte mono-ADP-ribosyltransferase in vitro. The modification reaction could be demonstrated in crude brain tissue extracts where selective ADP-ribosylation of both the alpha and beta chains of tubulin and of the high molecular weight microtubule-associated protein MAP-2 occurred. In experiments with purified microtubule protein, tubulin dimer, the high molecular weight microtubule-associated protein MAP-2, and another high molecular weight mirotubule-associated protein which may be a MAP-1 species were heavily labeled. Tubulin and MAP-2 incorporated [14C]ADP-ribose to an average extent of approximately 2.4 and 30 mol of ADP-ribose/mol of protein, respectively. Assembly of microtubule protein into microtubules in vitro was inhibited by ADP-ribosylation, and incubation of assembled steady-state microtubules with ADP-ribosyltransferase and NAD+ resulted in rapid depolymerization of the microtubules. Thus, the eukaryotic enzyme can ADP-ribosylate tubulin and microtubule-associated proteins to much greater extents than previously observed with cholera and pertussis toxins, and the modification can significantly modulate microtubule assembly and disassembly.

ADP Ribose Transferases↗