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Biomedical subjects

J D Wilson

Publications and source records attributed to J D Wilson.

At least 55 records · Page 3Linked to original sources
PubMed2000

Mycobacterium chelonae sepsis associated with long-term use of an intravenous catheter for treatment of hyperemesis gravidarum. A case report.

BACKGROUND: Of the 1-2% of pregnant women who develop hyperemesis, the great majority are managed successfully with antiemetics and, when needed, short courses of parenteral medications. Only rarely will chronic parenteral therapy be necessary. Such therapy may be associated with significant complications. CASE: A 38-year-old woman, gravida 3, para 1, induced abortion 1, with a history of hyperemesis in her first pregnancy, developed recurrent hyperemesis at 9 weeks' gestation. After four admissions and a 5.45-kg weight loss at 12 weeks' gestation, a Groshong catheter was placed in the left subclavian vein. The patient was then managed with home droperidol infusions and intravenous hydration as needed. At 30 weeks' gestation she developed tender, erythematous nodules over her legs and right arm. Culture from a biopsy of the nodules grew Mycobacterium chelonae, as did the catheter tip. M chelonae is a ubiquitous, opportunistic, nontuberculous (atypical) mycobacterium. The patient responded slowly to clarithromycin. At 37 weeks she delivered a healthy, 4,080-g, male infant. Three months postpartum the nodules continued to resolve slowly on clarithromycin. CONCLUSION: When chronic parenteral therapy is required for hyperemesis gravidarum, attention must be given to potential complications. Indwelling catheters should be removed as soon as possible.

Adult↗
PubMed1999

Influence of bacterial vaginosis on conception and miscarriage in the first trimester: cohort study.

OBJECTIVES: To assess whether bacterial vaginosis affects the rates of conception and miscarriage in the first trimester. DESIGN: Cohort study. SETTING: Assisted conception unit of a teaching hospital in Leeds. PARTICIPANTS: 867 consecutive women undergoing in vitro fertilisation. INTERVENTIONS: Screening for bacterial vaginosis with a Gram stained vaginal smear before egg collection. MAIN OUTCOME MEASURES: The presence of bacterial vaginosis or normal vaginal flora, and the rate of conception and miscarriage in the first trimester. RESULTS: 190 of 771 (24.6%) women had bacterial vaginosis. No difference in conception rate was found between those women with bacterial vaginosis and those with normal vaginal flora: 61 women (32.1%) and 146 of 493 women (29.6%) respectively (relative risk 1. 08, 95% confidence interval 0.85 to 1.39; odds ratio 1.12, 0.77 to 1. 64). However, 22 women (31.6%) with bacterial vaginosis who conceived had a significantly increased risk of miscarriage in the first trimester compared with 27 women (18.5%) with normal vaginal flora (crude relative risk 1.95, 1.11 to 3.42; crude odds ratio 2.49, 1.21 to 5.12). This increased risk remained significant after adjustment for factors known to increase the rate of miscarriage: increasing maternal age, smoking, history of three or more miscarriages, no previous live birth, and polycystic ovaries (adjusted relative risk 2.03, 1.09 to 3.78; adjusted odds ratio 2.67, 1.26 to 5.63). CONCLUSIONS: Bacterial vaginosis does not affect conception but is associated with an increased risk of miscarriage in the first trimester in women undergoing in vitro fertilisation, independent of other risk factors.

Abortion, Spontaneous↗
PubMed1999

Immune mechanisms associated with the rejection of fetal murine proislet allografts and pig proislet xenografts: comparison of intragraft cytokine mRNA profiles.

BACKGROUND: Previous in vivo depletion studies of CD4 and CD8 T cells indicated that different rejection mechanisms operate for proislet allografts and xenografts. The cellular and molecular mechanisms of acute proislet allograft and xenograft rejection have therefore been characterized and directly compared. METHODS: The intragraft cytokine mRNA profile in rejecting BALB/c (H-2d) proislet allografts was analyzed in control, CD4 T cell-depleted, and CD8 T cell-depleted CBA/H (H-2k) recipient mice using semi-quantitative reverse transcriptase-assisted polymerase chain reaction (RT-PCR). The cytokine profiles for proislet allografts and pig proislet xenografts at 3-10 days posttransplant were directly compared and correlated with graft histopathology. RESULTS: Allograft rejection was protracted (2-3 weeks), characterized by infiltrating CD8 T cells and CD4 T cells (no eosinophils) and was associated with a Th1-type CD4 T cell response (IL-2, IFN-gamma, and IL-3 mRNA) and a CD8 T cell-dependent spectrum of cytokine gene expression (IL-2, IFN-gamma, IL-3, and IL-10 mRNA). Xenograft rejection was rapid (6-8 days), involved predominantly CD4 T cells and eosinophils, and in contrast to allografts, exhibited intragraft mRNA expression for the Th2 cytokines IL-4 and IL-5. CONCLUSIONS: Proislet allograft and xenograft rejection differ in the tempo of destruction, phenotype of the cellular response and intragraft profile of cytokine mRNA. The recruitment of eosinophils only to the site of xenorejection correlates with IL4 and IL-5 mRNA expression. These findings suggest that different anti-rejection strategies may need to be developed to optimally target the allograft and the xenograft response.

Animals↗
PubMed1999

Brain stem auditory evoked potentials in the human fetus during labor.

OBJECTIVE: The aim of this study was to record, during labor, the brain stem auditory evoked potentials of the fetus from standard fetal scalp electrodes. STUDY DESIGN: A personal computer-based instrument was developed to record, during labor, brain stem auditory evoked potentials from 10 fetuses ranging in gestational age from 36 to >/=40 weeks. Auditory stimulus was provided by clicks (16/s) delivered on the mother's abdomen with an intensity of 120 dB. The evoked potential signals were digitized and averaged. Interfering artifacts were excluded from the averages. RESULTS: In 80% of the subjects, all the principal waveforms of the brain stem auditory evoked potentials-waves I, III, and V-were clearly identifiable. The latency for wave I ranged from 1.2 to 2.2 ms, wave III from 3.4 to 5.6 ms, and wave V from 5.8 to 8.4 ms. The morphologic features of the waveform and the interwave latency values were similar to those of normal term infants recorded in the past studies. CONCLUSION: We have reestablished that it is possible to record auditory evoked potentials during labor from fetal scalp electrodes. Brain stem auditory evoked potentials may be a useful screening tool for at least the severely neurologically damaged fetus.

Electrodes↗
PubMed1999

Fundamentals of health risk assessment. Use, derivation, validity and limitations of safety indices.

We investigated the way results of human health risk assessments are used, and the theory used to describe those methods, sometimes called the "NAS paradigm." Contrary to a key tenet of that theory, current methods have strictly limited utility. The characterizations now considered standard, Safety Indices such as "Acceptable Daily Intake," "Reference Dose," and so on, usefully inform only decisions that require a choice between two policy alternatives (e.g., approve a food additive or not), decided solely on the basis of a finding of safety. Risk is characterized as the quotient of one of these Safety Indices divided by an estimate of exposure: a quotient greater than one implies that the situation may be considered safe. Such decisions are very widespread, both in the U.S. federal government and elsewhere. No current method is universal; different policies lead to different practices, for example, in California's "Proposition 65," where statutory provisions specify some practices. Further, an important kind of human health risk assessment is not recognized by this theory: this kind characterizes risk as likelihood of harm, given estimates of exposure consequent to various decision choices. Likelihood estimates are necessary whenever decision makers have many possible decision choices and must weigh more than two societal values, such as in EPA's implementation of "conventional air pollutants." These estimates can not be derived using current methods; different methods are needed. Our analysis suggests changes needed in both the theory and practice of human health risk assessment, and how what is done is depicted.

Air Pollutants↗
PubMed1999

Inadequate cervical cytology--the need to audit individual smear takers' inadequate rates.

In order to assess the performance of individual smear takers, their rates of inadequate smears, due to insufficient material, were monitored between 1992 and 1996. Although the yearly average clinic inadequate rates were all at acceptable levels, there was great variation of rates between smear takers, ranging from 0% to 19.5%. Identification of individuals with unacceptably high inadequate rates allowed them to undergo further training. Continuous monitoring of these inadequate rates can be used to measure levels of performance amongst all smear takers, but is particularly useful for new smear takers, or those who have required retraining.

Adult↗
PubMed1999

Virilization of the male pouch young of the tammar wallaby does not appear to be mediated by plasma testosterone or dihydrotestosterone.

Virilization of the male urogenital tract of all mammals, including marsupials, is mediated by androgenic hormones secreted by the testes. We have previously demonstrated profound sexual dimorphism in the concentrations of gonadal androgens in pouch young of the tammar wallaby Macropus eugenii during the interval when the urogenital sinus virilizes. To provide insight into the mechanisms by which androgens are transported from the testes to the target tissues, we measured testosterone and dihydrotestosterone in plasma pools from tammar pouch young from the day of birth to Day 150. Plasma testosterone levels were measurable (0.5-2 ng/ml) at all times studied, but there were no differences between males and females. These low concentrations of plasma testosterone appear to be derived from the adrenal glands and not the testes. Plasma dihydrotestosterone levels in plasma pools from these animals were also low and not sexually dimorphic. We conclude that virilization of the male urogenital tract cannot be explained by the usual transport of testosterone or dihydrotestosterone in plasma but may be mediated by the direct delivery of androgens to the urogenital tract via the Wolffian ducts. Alternatively, circulating prohormones may be converted to androgens in target tissues.

Adrenal Glands↗
PubMed1999

Heterotopic mesenteric ossification ('intraabdominal myositis ossificans'): report of five cases.

Intraabdominal heterotopic ossification is a very uncommon disorder. We report five new cases, review the previous literature, and discuss the clinical and pathologic features of these lesions. The clinical features of the current cases and of those previously reported are remarkably similar. All patients were middle-aged to elderly men (range, 43-80 years; mean, 61 years) who had small bowel obstruction associated with heterotopic bone formation in the small bowel mesentery, often after one or more abdominal operations. In one case, an initial diagnosis of extraosseous osteosarcoma was considered. This unusual reactive process shares many of the clinical and pathologic features of myositis ossificans, as classically described in somatic soft tissues. We propose to designate this condition heterotopic mesenteric ossification.

Adult↗
PubMed1999

Effects of castration and androgen treatment on androgen-receptor levels in rat skeletal muscles.

The effects of castration and dihydrotestosterone (DHT) treatment on levels of skeletal muscle androgen receptor (AR) were examined in three groups of adult male rats: 1) intact normal rats, 2) rats castrated at 16 wk of age, and 3) rats castrated at 16 wk of age and given DHT for 1 wk starting at week 17. All animals were killed at 18 wk of age. Castration caused a decrease (P < 0.05) in the weights of the levator ani and bulbocavernosus muscles. The administration of DHT to the castrated rats increased (P < 0.05) the weights of the levator ani and bulbocavernosus muscles. Castration caused a significant downregulation of AR levels in the bulbocavernosus (P < 0.05) but had no significant effect on AR levels in the levator ani muscle. DHT administration to the castrated group upregulated AR levels in the bulbocavernosus and levator ani muscles. The plantaris muscle did not significantly (P > 0.05) change for any of the treatments. These findings suggest that the effects of castration and androgen replacement differentially affect skeletal muscle mass and AR levels.

Animals↗