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Biomedical subjects

E Thomas

Publications and source records attributed to E Thomas.

At least 235 records · Page 13Linked to original sources
PubMed1993

Increased prevalence of Helicobacter pylori antibodies among nurses.

BACKGROUND: Numerous studies have suggested that Helicobacter pylori infection in asymptomatic subjects is transmitted from person to person. Its prevalence is higher in the institutionalized setting. If that is the case, persons involved in patient care should have a higher prevalence of the infection. METHODS: We estimated the prevalence of H pylori antibodies among groups of asymptomatic medical and nursing staff and compared them with volunteer blood donors of similar age and sex. RESULTS: One hundred fifty-eight nurses and aides, 59 residents, 46 senior medical students, and 22 senior nursing students were enrolled in this study. Serum samples were tested for IgG antibodies against H pylori by enzyme-linked immunosorbent assay. Sixty-two (39%) of 158 nurses were found to be positive for antibodies to H pylori compared with 114 (26%) of 441 specimens from the blood donor group. Within the youngest age group (20 to 34 years), 13 (25%) of 51 nurses were positive for H pylori antibodies compared with 19 (13%) of 143 age-matched serum samples from the blood donor group. Within the middle age group (35 to 49 years), 32 (39%) of 83 nurses were positive for H pylori antibodies vs 43 (26%) of 167 age-matched blood donors. In the oldest age group (> 50 years), 17 (71%) of 24 nurses were positive for H pylori antibodies compared with 52 (40%) of 131 age-matched blood donors. Twenty-three (27%) of 86 nurses with 1 to 15 years of occupational exposure were positive for H pylori antibodies compared with 40 (56%) of 72 nurses with more than 15 years of occupational exposure. CONCLUSIONS: Nurses have an increased prevalence of H pylori antibodies that is significantly higher than the comparable prevalence of volunteer blood donors and is evident in the youngest age group. In addition, the increased prevalence is related to a longer duration of patient exposure in the nursing group.

Adult↗
PubMed1993

Anticonflict action of chlordiazepoxide in rats with combined lesions.

Lesions of brain areas thought to promote anxiety do not diminish the anticonflict effects of benzodiazepines (BZDs). After initial training in the lick-suppression conflict test, eight rats received electrolytic lesions of the amygdala, dorsal raphe, locus coeruleus, and mammillary bodies. Ten others received sham lesions. Postoperative testing revealed a significant increase in punished licking at two stages after surgery in lesioned animals when compared with their own preoperative baseline levels and with the punished licking of control animals. Systemic administration of chlordiazepoxide (CDP, 2.5-10.0 mg/kg) resulted in a comparable dose-dependent increase in punished licking in both groups. These results suggest that the several structures lesioned need not be intact for CDP to have an antianxiety effect. It appears that sites of anxiolytic action are much more widely spread than currently believed and that other brain areas should be considered.

Amygdala↗
PubMed1993

The role of the lateral septum in anxiolysis.

Behavior of rats in the water-lick conflict test was examined during stimulation, and after lesions of the lateral septal nucleus. Continuous low-current stimulation resulted in an anxiolytic effect, an increase in the number of licks, and hence in the number of shocks, during a signaled, punished period. This effect is similar to the one seen with peripheral administration of benzodiazepine and other anxiolytic agents. Rewarding medial forebrain stimulation did not have this effect. Conversely, septal lesions resulted in an anxiogenic effect, a significant decrease in the number of licks during the punished period. Lesions had this effect when the conflict behavior was already well established. Septal lesions performed before acquisition of the conflict behavior resulted in initial retardation of acquisition. The results suggest an important role for the lateral septum in the inhibition of anxiety and in the acquisition of behaviors reinforced by alleviation of anxiety.

Animals↗
PubMed1993

The development of functional ovarian cysts during pituitary down-regulation.

This study investigated the development of functional ovarian cysts during pituitary down-regulation prior to in-vitro fertilization (IVF), and identified 16 cases of cysts in 288 IVF cycles studied. Comparing the patients with functional ovarian cysts to the other 272 IVF cycles, there was no significant difference in age or incidence of endometriosis but significantly (P < 0.01) more patients with cysts had ovulatory dysfunction. The serum progesterone was < 5.7 nmol/l in all 16 patients with cysts on day 4 of the IVF cycle, and in eight of these patients the serum progesterone was < 5.7 nmol/l on the day buserelin was commenced. In 10 of the 16 patients with cysts, serum oestradiol concentrations remained elevated despite the prolonged use of buserelin, and the cysts were aspirated. The aspirate in all cases was clear without any suggestion of endometriosis. The cyst aspirates had significantly lower progesterone (P < 0.001), higher androstenedione (P < 0.01) and similar oestradiol concentrations to 10 follicular fluid samples collected at the time of oocyte retrieval. This study suggests that functional ovarian cysts may develop during pituitary down-regulation, and these cysts are follicular cysts rather than persistent corpora lutea or endometriomata.

Adult↗
PubMed1993

Chronic gastritis associated with infection due to Helicobacter pylori in southern Appalachian veterans with dyspepsia.

A prospective study of infection due to Helicobacter pylori in 104 Southern Appalachian veterans with upper gastrointestinal symptoms revealed a prevalence of 67%. There was no age difference observed between those with and without H pylori. The organism was shown to be present in 12 of 13 patients with duodenal ulcer (92%), 6 of 10 with gastric ulcer (60%), and 52 of 81 with nonulcer dyspepsia (64%). Using culture as standard, the urease test showed a sensitivity of 76% and specificity of 100%, while the biopsy stain had a sensitivity of 97%. The presence of acute inflammation in the antrum and body of the stomach closely correlated with the presence of the organism. Somewhat at variance with previous studies, our study indicated that H pylori in the body mucosa was strongly associated with chronic superficial gastritis with and without acute inflammation. Such a finding may reflect the natural history of infection due to H pylori and the advanced age of our patients.

Adult↗
PubMed1993

Sacral insufficiency fractures presenting as acute low-back pain. Biomechanical aspects.

Sacral insufficiency fractures are an often unsuspected cause of low-back pain in elderly women with osteopenia who have sustained unknown or only minimal trauma. The authors describe 10 cases of spontaneous sacral insufficiency fractures, confirmed by computed tomography, characterized by the onset of acute low-back pain. Differential clinical and radiographic diagnosis of these fractures is often difficult. Recognition of the characteristic scintigraphic patterns in sacral fractures, which are frequent in osteopenic patients, could avoid mistaken diagnoses and unnecessary tests or treatment. One of the striking feature of these sacral fractures is their invariable location. The fractures extend vertically in the sacral alae, parallel to the sacroiliac joints. They are located just lateral to the margins of the lumbar spine. This distribution suggests that such fractures could be partially caused by weight-bearing transmitted through the spine.

Aged↗
PubMed1993

Renal function and biopsy findings after 5 years' treatment with low-dose cyclosporin for psoriasis.

Renal biopsies were performed in eight patients with chronic plaque psoriasis who had been treated with low-dose cyclosporin (CyA) (range 1-6 mg/kg/day; average dose 3.3 mg/kg/day) for an average period of 5 years. In six of the eight patients biopsies showed features consistent with CyA nephrotoxicity. Tubular atrophy and arteriolar hyalinosis were present in all six, four had an increase in interstitium, and two showed an increased incidence of glomerular obsolescence. Two of the patients showed all of these features, two patients had three features, and the remaining patients had two features. Renal function was assessed by glomerular filtration rate (GFR) and serum creatinine. Both a fall in the GFR and a rise in the serum creatinine correlated with the severity of the features of CyA nephrotoxicity seen on biopsy. However, the best predictor of the biopsy findings was a failure of renal function to show significant improvement when CyA was discontinued for a month. CyA has been discontinued in two of the eight patients who had the most severe features of CyA nephrotoxicity on renal biopsy. In both patients there has been improvement of renal function after 1 year of follow-up.

Adult↗
PubMed1993

Isolation of Helicobacter pylori from saliva.

Helicobacter pylori was grown in low numbers from the saliva of one of nine patients who were positive for gastric H. pylori. The saliva-derived isolate from this patient was identical to the antral biopsy-derived isolate from the same patient and differed from isolates cultured from the antral biopsies of all other patients by soluble-protein electrophoresis, restriction endonuclease DNA analysis, and Southern blot hybridization. This is the first observation, to our knowledge, of the recovery of viable H. pylori from saliva.

Fatty Acids↗
PubMed1993

A highly specific and sensitive DNA probe derived from chromosomal DNA of Helicobacter pylori is useful for typing H. pylori isolates.

HindIII-digested DNA fragments derived from an EcoRI-digested 6.5-kb fragment of chromosomal DNA prepared from Helicobacter pylori ATCC 43629 (type strain) were cloned into the pUC19 vector. A 0.86-kb insert was identified as a potential chromosomal DNA probe. The specificity of the probe was evaluated by testing 166 non-H. pylori bacterial strains representing 38 genera and 91 species which included aerobic, anaerobic, and microaerophilic flora of the upper and lower gastrointestinal tracts. None of the 166 non-H. pylori strains hybridized with this probe (100% specificity), and the sensitivity of this probe was also 100% when H. pylori isolates from 72 patients with gastritis and with the homologous ATCC type strain were tested by dot blot hybridization. The capability of this probe for differentiating between strains of H. pylori was evaluated by Southern blot hybridization of HaeIII-digested chromosomal DNA from 68 clinical isolates and the homologous ATCC type strain of H. pylori. Fifty-one unique hybridization patterns were seen among the 69 strains tested, demonstrating considerable genotypic variation among H. pylori clinical isolates. We propose that this probe would be of significant value for conducting epidemiologic studies.

Bacterial Typing Techniques↗
PubMed1993

Delayed cytopathicity of a feline leukemia virus variant is due to four mutations in the transmembrane protein gene.

Two molecularly cloned, replication-defective variants of feline leukemia virus, called 61B and 61C, have both been shown to cause fatal immunodeficiency in cats when coinfected with a replication-competent, minimally pathogenic helper virus, but 61B exhibits a longer latency period between infection and disease (J. Overbaugh, E. A. Hoover, J. I. Mullins, D. P. W. Burns, L. Rudensey, S. L. Quackenbush, V. Stallard, and P. R. Donahue, Virology 188:558-569, 1992). Infection of the 3201 feline T-cell line with 61B plus helper virus also results in longer time from infection to cytopathic effect compared with 61C plus helper virus, providing an in vitro system with which to study the mechanism for this difference. We report that the primary determinant of cytopathicity of 61B maps to gp70, the extracellular envelope glycoprotein. The long latency of 61B, on the other hand, maps to the extracellular portion of the envelope transmembrane protein, in which there are only four predicted amino acid differences between 61B and 61C. These differences render 61B replication defective, and two of the predicted amino acid changes lie in a region that is highly conserved among many retroviruses. The eventual onset of 61B cytopathicity in cell culture was associated with the outgrowth of an apparent recombinant virus that encodes the pathogenic gp70 of 61B and replaces the transmembrane protein of 61B with that of the helper virus. Thus, during in vitro infection, a cytopathic virus evolved from a replication-defective virus and a nonpathogenic virus, suggesting that recombination between multiple variants in natural infection may influence progression of feline leukemia virus-associated immunodeficiency disease.

Amino Acid Sequence↗
PubMed1993

Purification and identification of polyclonal IgE antibodies from ragweed-sensitized dog sera.

We have purified and characterized polyclonal dog IgE. Serum IgE was precipitated by (NH4)2SO4 and then purified by two different procedures. Ion exchange on DEAE-Sephacel, followed by HPLC using Tonen hydroxylapatite and then Protein G-Sepharose, produced a highly purified IgE fraction (No. 1) free of IgG, IgA and IgM as measured by ELISA, but recovery of IgE as measured by passive cutaneous anaphylaxis was low. Gel filtration on Sephacryl S-300, Con A-Sepharose and Protein G-Sepharose recovered 18% of initial IgE, 0.02% IgG, 0.4% IgM and 0.3% IgA. This IgE fraction (No. 2) was used to induce antibody production in rabbits. Western blot analysis was then performed for dog IgE fractions No. 1 and 2. Using the rabbit anti-dog IgE, a prominent IgE band with an apparent molecular mass of 226 kD was identified in fractions No. 1 and 2 subjected to nonreducing SDS-PAGE. This band also reacted with anti-human IgE, but not with anti-dog IgG or anti-dog IgA. Under reducing conditions the approximate molecular mass for the IgE & chain, estimated by Western blot using rabbit anti-dog IgE, was 73 kD, providing a molecular mass of 196 kD for dog IgE.

Allergens↗
PubMed1993

"Whoosh" test as a teaching aid in caudal block.

Fifty-three patients presenting for minor gynaecological procedures received caudal blocks performed by residents. These residents used the standard technique which relied on the "give" felt as a needle penetrates the sacrococcygeal membrane and the loss of resistance to air when the needle is correctly placed. The "whoosh" test was noted by the supervising anaesthetist who did not reveal his findings to the residents. A positive test consisted of a characteristic "whoosh" sound on auscultation of the thoracolumbar region when 2 to 3 ml of air was injected into the caudal extradural space. The predictive value of a positive test was found to be 78%, 80.7% and 97.7% (P < 0.01) for a positive "give", loss of resistance and "whoosh" test respectively. Negative tests had no predictive value for "give" and loss of resistance whilst the predictive value of an absent "whoosh" was 100% (P < 0.05). Thus we conclude that the "whoosh" test is an excellent aid in the teaching of caudal anaesthesia.

Adult↗