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Biomedical subjects

M E Wilson

Publications and source records attributed to M E Wilson.

At least 307 records · Page 17Linked to original sources
PubMed1988

Effects of a natural versus artificial environment on the tempo of maturation in female rhesus monkeys.

To identify factors that regulate the tempo of growth and puberty, the present study examined how the environment influenced the timing of menarche and first ovulation in rhesus monkeys and how these events were related to differential rates of growth. Spring-born females were raised from 12 months of age under natural outdoor conditions (OH; n = 6) or indoors (IH; n = 9) under a controlled photoperiod (12h of light, 12h of darkness) and temperature (20-23 C). Ages at the initial increases in serum bioactive LH levels (27.7 +/- 0.7 vs. 31.4 +/- 1.0 months), menarche (26.0 +/- 0.7 vs. 32.5 +/- 0.9 months), and first ovulation (33.9 +/- 1.4 vs. 43.5 +/- 0.3 months) were significantly advanced in IH compared to OH females. First ovulation for the OH females occurred exclusively in October and November of the fourth year, whereas the distribution of first ovulation of IH females was biomodal, with seven of nine occurring in November or December at 31.8 +/- 0.5 months, and two of nine ovulating in September or October at 41.2 +/- 0.5 months. Serum levels of PRL varied seasonally in OH females throughout development, with peaks in July and nadirs in October. A similar rhythm was observed for IH females during the first 12 months of indoor housing, after which point the period decreased from 11.9 +/- 0.5 to 9.3 +/- 0.6 months. Overall increments in body weight did not differ between groups. An acceleration of growth in both crown-rump and tibial lengths occurred just before menarche in both groups, and this occurred at about 26 months for IH and about 32 months for OH females. Skeletal maturity was significantly advanced at 27 months in IH females and at every chronological age thereafter. Serum concentrations of somatomedin-C and GH paralleled group differences in bone maturation. Both hormones were significantly elevated by 16-18 months of age in IH animals compared to OH females and remained so until 34-36 months of age. Although a distinct seasonal rhythm in both GH and somatomedin-C was evident in OH animals, no such pattern was observed in IH females. These data suggest that exposure to an outdoor environment moderates the tempo of both sexual and skeletal maturation. The acceleration in reproductive development in animals exposed to a constant environment was associated with an acceleration in bone maturation, suggesting that common factors may be responsible for the initiation of both events.

Aging↗
PubMed1988

Mycoplasma hominis surgical wound infection: a case report and discussion.

A patient with Mycoplasma hominis infection of a clean surgical wound that contained a prosthetic vascular graft had clinical findings similar to those observed in patients with acute bacterial infections. Etiologic diagnosis was delayed because M. hominis is not appreciated as a cause of surgical wound infections and because of its special growth characteristics. Confirmation of M. hominis infection requires awareness on the part of the clinician and assistance from an informed microbiologist. The organism can be recovered by means of media and techniques available in most microbiology laboratories. Although M. hominis has been reported to sporadically infect wounds, it is possible that many other wound infections with this organism are being missed. The clinical settings in which mycoplasmal infections might be expected are described.

Adult↗
PubMed1988

Absence of diarrhea in toxic megacolon complicating Clostridium difficile pseudomembranous colitis.

We describe a patient with Clostridium difficile-associated pseudomembranous colitis who presented with toxic megacolon without diarrhea. The discussion includes a brief review of the literature, and suggests an important role for endoscopy in the diagnosis of pseudomembranous colitis and, possibly, as part of the therapy for toxic megacolon associated with Clostridium difficile colitis. The unusual combination of toxic megacolon without antecedent diarrhea should be recognized as a possible manifestation of antibiotic-associated pseudomembranous colitis, especially in the setting of simultaneous antimicrobial and opiate administration. Early diagnosis and disease-specific intervention can be lifesaving.

Aged↗
PubMed1987

Bluefish-associated scombroid poisoning. An example of the expanding spectrum of food poisoning from seafood.

Five persons who attended a medical conference developed symptoms suggestive of an intoxication after a common meal. Although the symptoms were recognized as typical of scombroid poisoning, no fish of the Scrombridae family had been served. However, food histories implicated bluefish (Pomatomus saltatrix). The initially frozen bluefish had been improperly handled in storage and thawing. Elevated levels of histamine, putrescine, and cadaverine were detected in uncooked samples. This outbreak emphasizes that scombroid-type poisoning (1) can be caused by nonscombroid fish such as bluefish, (2) is probably more common than currently recognized, and (3) may become even more widespread as fish become a larger part of our diet. Physicians who work in conjunction with public health officials can help prevent additional cases and outbreaks.

Animals↗
PubMed1987

Elevation of serum IgG levels and normalization of T4/T8 ratio after hepatitis in a patient with common variable hypogammaglobulinemia.

Acute hepatitis infection developed in a 47-year-old male patient with common variable hypogammaglobulinemia as a consequence of plasma transfusion therapy. Coincident with increases in serum transaminase activities indicative of acute hepatitis, serum IgG levels continued to rise to 506 mg/dl. When plasma replacement therapy was stopped, a transient decline in IgG level (to 371 mg/dl) was produced, followed by a sharp increase in IgG to 607 mg/dl. During this period, the patient's T4/T8 ratio, which had been inverted (0.89), exhibited significant normalization to 1.57. Nevertheless, the patient failed to produce specific antibody after immunization with a number of defined antigens. The mechanism whereby this presumed non-A, non-B hepatitis augmented endogenous IgG production in this patient remains unknown but may be related to diminished suppressor T cell activity. The patient's inability to produce specific antibody during this period suggests an underlying defect in one or more lymphocyte subsets involved in either helper T cell activity and/or immunologic memory.

Agammaglobulinemia↗
PubMed1987

Capnocytophaga species: increased resistance of clinical isolates to serum bactericidal action.

Capnocytophaga, a newly recognized genus of capnophilic gram-negative bacilli, is part of the normal oral flora. The capacity of Capnocytophaga to cause sepsis and local infections in both immunocompromised and nonimmunocompromised hosts has been documented. Given the recognition that serum resistance may contribute to the virulence of some gram-negative bacteria, we attempted to define the serum sensitivity of clinical isolates of Capnocytophaga from blood and other sites of infection. Whereas nine of nine isolates from human subgingival plaque showed greater than 95% loss of viability under standardized assay conditions, nonoral isolates exhibited variable serum sensitivity. Six of six isolates from blood showed considerable serum resistance (mean survival, 59.7% +/- 38.3%; range, 14.4%-113.3%). Comparison of the electrophoretic mobilities of lipopolysaccharides (LPSs) from sensitive and resistant strains revealed reduced LPS heterogeneity and lower apparent molecular weight among serum-resistant strains. Thus, serum resistance, possibly influenced by LPS structure, may be an important factor contributing to the pathogenic potential of Capnocytophaga spp.

Blood Bactericidal Activity↗
PubMed1987

The effect of season on the induction of sexual behavior by estradiol in female rhesus monkeys.

Rhesus monkeys housed in an outdoor environment are seasonal breeders, with ovulations and concomitant sexual behavior limited to the fall and winter months. To determine if there is a seasonal difference in the capacity of physiological levels of estradiol (E2) to induce sexual behavior in ovariectomized rhesus monkeys housed outdoors, subjects living in a social group were treated with subcutaneous E2 implants in a counter-balanced design during the nonbreeding season (May-July) and during the breeding season (September-November). Serum E2 levels were monitored by obtaining blood samples twice a week. Three levels of E2 were studied: baseline (less than 30 pg/ml), follicular (100 pg/ml), and periovulatory (200 pg/ml). Two of five adult males in the group were injected with human chorionic gonadotropin (hCG) twice a week to insure that males with high testosterone levels were present during each season. Focal observations of behavior of 15 minutes' duration on each subject were conducted 5 days per week, with frequencies and durations of social, sexual, and solitary behaviors recorded. Concomitant 2-h group scans were made to record all occurrences of mounting behavior. Neither heterosexual serial mounting nor seminal plugs were ever observed in E2-treated females during the summer months. In contrast, copulation and seminal plugs were observed in subjects at both treatment levels during the fall. While E2-treated females engaged in homosexual mounting behavior during both summer and fall, E2 treatment resulted in heterosexual copulation only during the fall. Changes in patterns of social behavior paralleled changes in sexual behavior and were significantly affected by treatment and season, with more male-female interactions during the fall months.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Seasonal modulation of luteinizing-hormone secretion in female rhesus monkeys.

The seasonal restriction of ovulations in rhesus monkeys is thought to be due to enhanced estradiol (E2)-negative feedback suppression of luteinizing hormone (LH) during the spring and summer anovulatory months. This hypothesis was examined in seven ovariectomized monkeys housed in an outdoor environment and treated with various doses of E2 in a counterbalanced design during both the anovulatory season (May-Jul) and the breeding season (Sep-Nov). Subcutaneous implants of E2 produced levels that mimicked late follicular (LF-100 pg/ml) or periovulatory concentrations (PO-190 pg/ml). Analyses of twice weekly serum samples revealed that during the period of no E2 treatment (NT), basal levels of bioactive LH were significantly lower in the summer than the fall. Although treatment with both doses of E2 lowered basal LH levels during both seasons, the decrease in LH was significantly greater during the summer. Samples collected at 15-min intervals for 2 h revealed that during NT, LH pulses were significantly slower during the summer than in the fall, whereas pulse amplitude did not differ between seasons. Treatment with both doses of E2 either abolished or significantly reduced both LH pulse amplitude and frequency in the summer. In contrast, LH pulses during the fall were not affected by E2 treatment. Response to treatment with LH-releasing hormone (5 micrograms/kg i.v.) revealed that release was significantly reduced during E2 treatment in the summer. These data indicate that seasonal changes in the environment influence both nongonadal control and E2-negative feedback inhibition of LH secretion. The reduced ability of E2 to maximally suppress LH release in the fall can thus account for the seasonally delimited pattern of ovulations observed in rhesus monkeys.

Animals↗
PubMed1987

Role of high-avidity binding of human neutrophil myeloperoxidase in the killing of Actinobacillus actinomycetemcomitans.

The binding of the neutrophil enzyme myeloperoxidase (MPO) to microbial surfaces is believed to be the first step in its microbicidal activity. The MPO-H2O2-Cl- system is responsible for most oxidative killing of Actinobacillus actinomycetemcomitans by human neutrophils. There appear to be three forms of MPO (MPO I, II, and III), all of which can kill this organism in the presence of H2O2 and chloride. In this study, we characterized the binding of native human neutrophil MPO to A. actinomycetemcomitans by an elution procedure dependent on the cationic detergent cetyltrimethylammonium bromide. Binding of native MPO was rapid and reached apparent equilibrium within 1 min. A proportion of binding under equilibrium conditions was saturable and highly avid, with a capacity of 4,500 sites per cell and a dissociation constant of 7.9 X 10(-10) M. At equal protein concentrations, more MPO III bound than MPO II, and more MPO II bound than MPO I. The high-avidity interaction was inhibitable with yeast mannan and with the serotype-defining mannan of A. actinomycetemcomitans. Binding was also partially reversible with yeast mannan. MPO bound to the high-avidity sites did not oxidize guaiacol but oxidized chloride, as detected by the chlorination of taurine. MPO bound to the high-avidity sites was incapable of killing A. actinomycetemcomitans alone in the presence of H2O2 and Cl-, but potentiated killing when sufficient additional MPO was provided. The killing of A. actinomycetemcomitans by the MPO-H2O2-Cl- system was inhibited by yeast mannan and a serotype-defining mannan of A. actinomycetemcomitans. We conclude that high-avidity binding of MPO to the surface of A. actinomycetemcomitans is a mannan-specific interaction and that MPO bound to the high-avidity sites is essential but not alone sufficient to kill A. actinomycetemcomitans.

Actinobacillus↗
PubMed1987

Location, transcription, and sequence of a baculovirus gene encoding a small arginine-rich polypeptide.

The nucleotide sequence of the cDNA of an abundant late 0.5-kilobase transcript of Autographa californica nuclear polyhedrosis virus revealed a small open reading frame encoding an arginine-rich 6.9-kilodalton protein. The predicted amino acid composition of the 6.9-kilodalton protein was essentially identical to that of the core protein of viral nucleocapsids. The precise location of the 5' and 3' ends of the transcript were confirmed by S1 nuclease and primer extension analyses. Multiple overlapping transcripts through this region include three early and three abundant late RNAs which are transcribed counterclockwise and one transient RNA which is transcribed clockwise with respect to the physical map of the virus.

Arginine↗
PubMed1987

Early histopathology of experimental infection with Leishmania donovani in hamsters.

The extracellular promastigote stage of Leishmania donovani is inoculated by a phlebotomine sandfly into the skin of a susceptible host, after which visceral dissemination and clinical disease may ensue. Using a hamster model we examined the histopathology of early infection with L. donovani after intradermal inoculation of cultured promastigotes. The initial response was a mixed polymorphonuclear (PMN)-mononuclear phagocyte infiltrate, noted between 1 and 24 hr after inoculation, which became primarily mononuclear by 48 hr. Parasites were initially found intracellularly in both PMN's and mononuclear phagocytes, but by 48 hr they had assumed amastigote-like morphology and were found exclusively in macrophages. The number of parasites per infected macrophage increased during the first week after inoculation, suggesting that intracellular replication of the organism was taking place. This was followed by the formation of granulomas between 4 and 6 wk. By 8 wk intracellular parasites were largely gone. The histologic response was consistent with early destruction of parasites in PMN's, and survival and replication of L. donovani in macrophages. Cutaneous infection with the parasite was eventually controlled locally, coincident with granuloma formation. Despite these local responses, the organism was able to disseminate and eventually produce typical visceral leishmaniasis.

Animals↗
PubMed1987

Orbital cellulitis following strabismus surgery.

Orbital cellulitis is a rare complication of extraocular muscle surgery. Two cases have been reported since 1935. No report of this sight-threatening and life-threatening complication of strabismus surgery has appeared since computerized tomography became readily available. The following is a report of a case of orbital cellulitis occurring unilaterally following bilateral strabismus surgery in which computerized tomography was helpful in verification and management. Early antibiotics resulted in a favorable outcome. The case is compared to those reported by von Noorden.

Cefotaxime↗
PubMed1986

Evidence that Leishmania donovani utilizes a mannose receptor on human mononuclear phagocytes to establish intracellular parasitism.

The pathogenic protozoan Leishmania donovani must gain entrance into mononuclear phagocytes to successfully parasitize man. The parasite's extra-cellular promastigote stage is ingested by human peripheral blood monocytes or monocyte-derived macrophages in the absence of serum, in a manner characteristic of receptor-mediated endocytosis. We have found remarkable similarities between the macrophage receptor(s) for promastigotes and a previously characterized eucaryotic receptor system, the mannose/fucose receptor (MFR), that mediates the binding of zymosan particles and mannose- or fucose-terminal glycoconjugates to macrophages. Ingestion of promastigotes by monocyte-derived macrophages was inhibited by several MFR ligands. Mannan (2.5 mg/ml) decreased ingestion by 63.7% (p less than 0.001), and the neoglycoproteins mannose-BSA and fucose-BSA (20 micrograms/ml) inhibited parasite ingestion by 46.5% and 39.6%, respectively (p less than 0.04). In contrast, promastigote ingestion by monocytes was unaffected by MFR ligands. These results are consistent with reports that MFR activity is present in monocyte-derived macrophages but not in monocytes. Furthermore, attachment of promastigotes to macrophages, assessed by using cytochalasin D to prevent phagocytosis, was reduced 49.8% by mannan. Reorientation of the MFR to the ventral surface of the cell was achieved by plating macrophages onto mannan-coated coverslips, reducing MFR activity on the exposed cell surface by 94% as assessed by binding of 125I-mannose-BSA. Under these conditions, ingestion of promastigotes was inhibited by 71.4% (p less than 0.006). Internalization of the MFR by exposure of macrophages to zymosan before infection with promastigotes resulted in a 62.3% decrease in parasite ingestion (p less than 0.006). Additionally NH4Cl, a weak lysosomotropic base that impairs MFR recycling, decreased macrophage ingestion of promastigotes by 38.2% (p less than 0.03, 30 mM NH4Cl). Subinhibitory concentrations of NH4Cl (10 mM) and of mannan (0.25 mg/ml) together inhibited parasite ingestion by 76.4% (p less than 0.002). These studies suggest that L. donovani promastigotes may utilize a receptor system on human monocyte-derived macrophages, the MFR, to efficiently parasitize the human host.

Adult↗
PubMed1986

Evidence for and partial characterization of three major and three minor chromatographic forms of human neutrophil myeloperoxidase.

Myeloperoxidase (MPO) is an enzyme found in the azurophil granules of neutrophils. Cation-exchange chromatography on carboxymethyl-cellulose previously has been used to demonstrate the heterogeneity of the peroxidase enzymes isolated from human neutrophils. In this study, fast protein liquid chromatography (FPLC) was used to separate and purify three major (I, II, and III) and three minor (IIa, IIIa, IIIb) forms of MPO from isolated neutrophil granules. Purity was confirmed by polyacrylamide gel electrophoresis in the presence of cetyltrimethylammonium bromide (CETAB-PAGE), by crossed immunoelectrophoresis, and by spectral characteristics. All three major forms were indistinguishable by immunodiffusion against rabbit antiserum, scanning spectrophotometry, and amino acid composition. They differed in their elution from a cation-exchange resin, inhibition by 3-amino-1,2,4-triazole, migration rate in CETAB-PAGE, and subunit molecular weight. Subunit molecular weight was examined using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). All three major forms appeared to consist of heavy (H), intermediate (M), and light (L) peptides. The M peptide appeared to be derived from the H subunit. All L subunits exhibited a molecular weight of 14,500. The molecular weights for the H subunits varied, and were 60,000, 59,000, and 57,000 for MPO I, II, and III, respectively. The molecular weights for the M peptides were 44,100, 43,000, and 42,000 for MPO I, II, and III, respectively. The treatment of neutrophils, granules, and extracts with protease inhibitors and sodium azide did not block the appearance of three major forms of MPO. Thus, neither protease activity nor MPO autooxidation during extraction and purification procedures is responsible for the appearance of multiple chromatographic forms of MPO derived from human neutrophils.

Amino Acids↗