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Biomedical subjects

D White

Publications and source records attributed to D White.

At least 181 records · Page 10Linked to original sources
PubMed1993

Sexual issues and condom use among injecting drug users.

Recent surveys of injecting drug users reveal that their injecting behaviours have changed in the light of HIV, but their sexual behaviours have not and, in particular, they remain reluctant to use condoms to reduce the risks of sexual transmission. In an attempt to explore this issue further the present study assessed the behaviours and attitudes of injecting drug users to sexual issues, including condom use. Condom use was low. Obstacles to their use included for some a desire to conceive, for many a belief in their infertility, a perceived invulnerability to HIV infection through their sexual behaviour patterns, a dislike of condoms and difficulty in negotiating condom use with partners. The lifestyle of drug users may also have an influence on condom use. Many drug users funded their habit through illegal activities including prostitution, theft and fraud. The association between these and other factors and condom use are explored.

Adult↗
PubMed1993

Plastic surgery applicants in 1992.

All the applicants to plastic surgery residency programs who participated in the residency matching program for 1992 were reviewed. Data were collected on age, sex, race, nationality, place of birth, undergraduate education, medical education, postgraduate training, research activity, and evaluation scores. Findings indicate that applicants interested in academic careers are significantly more likely to have published research and are generally rated higher in categories of intellectual curiosity, performance, and intelligence by evaluators. Women and some minorities were underrepresented when compared with recent medical school graduating classes. We recommend a longitudinal study of applicants to correlate career achievement with applicant characteristics. We also recommend some changes in the application and evaluation process and in efforts to interest women and minorities in the specialty.

Adult↗
PubMed1993

Absence of functional inhibition of cloned human beta 2-adrenergic receptors by autoantibodies in asthmatic subjects.

Using guinea-pig lung membranes and cloned human beta 2-receptor adrenergic receptors the effects of whole serum, plasma, purified immunoglobulins and cellular activation products on beta 2-adrenergic receptor ligand binding and function were investigated. Sera from 24 non-asthmatic subjects and 115 asthmatics in different clinical categories were studied. There were no significant differences between antagonist ([125I] cyanopindolol) inhibition mediated by serum, plasma or by purified IgG when the asthmatics were compared with non-asthmatics. There was also no inhibition of 10(-6) M isoproterenol stimulated cAMP release from L cells expressing human beta 2-adrenergic receptors, by plasma, DEAE purified IgG fractions from asthmatics and non-asthmatics, or by products of activated platelets or lymphocytes. Since we have no evidence that immunoglobulins from asthmatic subjects exert functional inhibition of human beta 2-adrenergic receptors we conclude that autoantibodies to the beta 2-adrenergic receptors do not play an important functional role in the pathophysiology of asthma.

Adrenergic beta-Agonists↗
PubMed1993

Evidence for a single gene effect causing polycystic ovaries and male pattern baldness.

OBJECTIVE: Polycystic ovary syndrome is one of the most common endocrine disorders but its aetiology remains unknown. It is highly prevalent within families, suggesting a genetic basic for the syndrome, but the mode of inheritance is unclear. The purpose of this study was to determine the mode of inheritance of polycystic ovary syndrome, within the families of affected individuals, by classic segregation analysis. DESIGN: All first degree relatives of affected individuals were screened for the presence or absence of polycystic ovaries in post-menarchal-premenopausal women and early onset male pattern baldness (MPB) in the males. In extended pedigrees, assignment of affected status in post-menopausal women was made by consideration of the clinical history alone. PATIENTS: Fourteen women (probands), presenting with a variety of clinical symptoms, were identified sequentially as having polycystic ovaries (PCO) by ultrasound scan. They were examined in detail to determine their family structure, clinical and endocrine status. Ten families were found to have sufficient members for further study. MEASUREMENTS: All family members had their body mass index calculated, their degree of hirsutism assessed using the Ferriman and Gallwey score and serum levels of gonadotrophins (FSH and LH), testosterone, prolactin and 17 alpha-hydroxyprogesterone measured by radioimmunoassay. A careful reproductive history was taken for each woman and any menstrual disturbance was noted. Obese probands had their glucose and insulin response to a standard 75-g oral glucose tolerance test determined. Each male family member was also assessed for the degree and time of onset of balding. RESULTS: First degree female relatives of affected individuals had a 51% chance of being affected. Early onset male pattern baldness (MPB) was found to be an accurate phenotype for obligate male carriers. Each family showed autosomal dominant inheritance for PCO with greater than 90% penetrance. CONCLUSIONS: We postulate that PCO and male pattern baldness are caused by alleles of the same gene which affect androgen production or action. The different frequencies of PCO and male pattern baldness arise from differing thresholds for phenotypic expression in females and males respectively. The modifying effects of other genes is the most likely explanation of the somewhat variable phenotype.

Adult↗
PubMed1993

Preliminary, dermatologic first step criteria for lupus erythematosus and second step criteria for systemic lupus erythematosus.

BACKGROUND: Comparisons of cases of systemic lupus erythematosus (SLE) with cases of rheumatoid arthritis and other rheumatologic disorders affords the basis of the 1982 revised criteria of the American Rheumatism Association (ARA) for classifying SLE cases. We address three questions: Do comparisons of LE cases with non-LE cases that have suggestive skin lesions yield criteria for use in dermatology clinics for primary classification of cases with photo distributions of skin lesions? Do comparisons of SLE with cutaneous LE cases yield the same or similar criteria to the revised ARA criteria for SLE? How should subacute cutaneous LE cases be evaluated for signs of significant systemic involvement? METHODS: Discriminant analyses on 168 cases with skin lesions suggestive of LE were performed using data based on the ARA criteria for SLE and study factors for cutaneous LE suggested by the European Academy of Dermatology and Venereology. RESULTS: These yielded two sets of criteria: (1) The 11 preliminary, dermatologic first step criteria (10 plus 1 for discoid lesions and histology) serve to classify cases as LE or non-LE. (2) The 11 preliminary, dermatologic second step criteria classify LE cases as cutaneous LE or systemic LE. Interestingly, 5 of 11 of these second step criteria differ from the 11 ARA criteria for systemic LE. These second step criteria afford a useful means of distinguishing between subacute cutaneous LE cases with or without significant systemic involvement. CONCLUSIONS: The study factors included in both the first and the second step criteria fall into three groups, notably clinical criteria, laboratory criteria, and "added study factors." The latter factors distinguish between the groups compared (LE vs. non-LE and cutaneous vs. systemic LE) but not as well as the study factors included as "criteria."

Humans↗
PubMed1993

Exteriorized chronic aorto-caval arteriovenous access shunts in the baboon (Papio cynocephalus).

A chronic arteriovenous (AV) blood access shunt has been developed in baboons. It is composed of silicone rubber tubing extensions bonded to vascular graft polytetrafluoroethylene (ePTFE) cuffs, for creating anastomoses with the distal aorta and inferior vena cava. Following surgical implantation, shunts remain patent for months (X = 9 +/- 2.5 months) and provides long-term ex vivo access to non-anticoagulated blood (Mean Blood Flow = 312 +/- 69 mL/min).

Animals↗
PubMed1993

Impact of intrauterine exposure to phencyclidine (PCP) and cocaine on neonates.

A total of 505 newborns who were exposed to illicit drugs during intrauterine life were studied to investigate the prevalence, growth parameters, newborn manifestations, and other effects of intrauterine exposure to cocaine and phencyclidine (PCP). The results support the hypotheses that both drugs have serious effects on growth parameters, but this effect was much more pronounced in the cocaine group than in the PCP group. Furthermore, the incidence of borderline microcephalic infants (head circumferences less than the 10th percentile) was much higher in the cocaine group. It also appears that the signs and symptoms observed in both groups are not withdrawal manifestations typically seen in narcotic-exposed infants; rather, these symptoms are true drug effects and should not be considered manifestations of drug withdrawal symptoms.

Cocaine↗
PubMed1992

HLA association with response and toxicity in melanoma patients treated with interleukin 2-based immunotherapy.

Peripheral blood lymphocytes from 146 patients with metastatic melanoma undergoing interleukin 2 (IL-2)-based immunotherapy were characterized for HLA A, B, Cw, DR, DQw, and DRw specificities. Patients had been enrolled into sequential treatment protocols with either IL-2 alone (28) or in combination with tumor-infiltrating lymphocytes (TILs) (86), alpha-interferon (26), lymphokine-activated killer cells (16), radiation therapy (7), cyclophosphamide (3), tumor necrosis factor (1), and interleukin 4 (1) for a total of 168 courses of therapy. HLA phenotype was then correlated with response rate and toxicity to IL-2. We noted: (a) a significant difference in the frequency of A11 (20.5% versus 10.2%; P < 0.05) allele between melanoma patients and the North American Caucasian population; (b) a significantly higher frequency of A11 phenotype among responders (40.5%) than in the melanoma patient population (20.5%; P < 0.01), which was even more obvious among patients responding to TIL therapy (47.4% versus 22.1%; P < 0.05); within TIL patients, responders also had an increased frequency of A19 (42.1% versus 25.6%; P < 0.05); (c) a correlation between the number of TILs received and response rate (P < 0.005); and (d) an association between DR4 haplotype and decreased tolerance to IL-2 among the patients receiving TILs (P = 0.01). These results suggest that, in melanoma patients, some HLA Class I specificities may predict for a greater likelihood of response to IL-2-based therapy, while HLA Class II phenotype correlates with tolerance to the combination of TIL and IL-2 therapy.

Drug Administration Schedule↗
PubMed1992

Early treatment with parenteral penicillin in meningococcal disease.

OBJECTIVE: To measure the effect of parenteral antibiotics given before admission to hospital on mortality and on bacteriological investigations in meningococcal disease. DESIGN: Retrospective review of hospital notes and laboratory and public health medicine department records. SETTING: Three health districts in south west England. SUBJECTS: Patients with meningococcal disease in Gloucester district presenting between 1 January 1982 and 31 December 1991 (n = 190); patients with meningococcal disease in Plymouth (n = 118) and Bath (n = 73) districts presenting between 1 January 1988 and 31 December 1991 (total = 381). MAIN OUTCOME MEASURE: Number of deaths from meningococcal disease. RESULTS: Parenteral antibiotic given by general practitioners was associated with a substantial reduction in mortality (from 9% to 5%; relative risk 0.6, 95% confidence interval 0.2 to 1.5); patients with a rash were more likely to be given parenteral antibiotics, and mortality was further reduced (from 12% to 5%; 0.5, 0.2 to 1.4). In a district where such treatment was regularly encouraged its use increased from 5% to 40% of cases over 10 years (p = 0.00001). Treatment with parenteral antibiotics before admission made isolation of meningococci from blood and cerebrospinal fluid less likely but did not affect nasopharyngeal cultures. CONCLUSIONS: General practitioners should carry benzylpenicillin in their emergency bags at all times and should administer it promptly, preferably intravenously, whenever meningococcal disease is suspected, unless the patient has had an anaphylactic reaction to penicillin. Specimens for culture should include a nasopharyngeal swab.

Humans↗
PubMed1992

A phenotypically and karyotypically stable human thyroid epithelial line conditionally immortalized by SV40 large T antigen.

Primary cultures of normal human neonatal thyroid follicular cells were transfected with a plasmid expressing a temperature-sensitive (tsA58) mutant of SV40 large T antigen. An epithelial cell line, designated B-thy-ts.1, was obtained which showed tight temperature-dependent growth. In sharp contrast to previous such lines, which were derived from adult thyroid, B-thy-ts.1 has retained a well-differentiated phenotype as reflected in its morphology and cytokeratin expression pattern. In addition to phenotypic stability the line also displays an unusually stable karyotype, lacking the usual clastogenic effects of SV40, which we speculate to result from a greater DNA repair capacity of its cell of origin. B-thy-ts.1 should be a particularly useful tool with which to study the effects of activated oncogenes on epithelial growth and differentiation.

Antigens, Polyomavirus Transforming↗
PubMed1992

A thin-layer chromatographic method to determine process impurities in leucovorin calcium.

A densitometric thin-layer chromatographic method for the analysis of process impurities in leucovorin calcium was developed and validated. Using this method, folic acid, N10-formyldihydrofolic acid, p-aminobenzoic acid, and N-(4-aminobenzoyl)-L-glutamic acid were monitored with a limit of detection of approximately 0.1% each. Both absorbance and fluorescence densitometric evaluations were utilized; fluorescence evaluation selectively detected impurities that were not chromatographically resolved from leucovorin.

4-Aminobenzoic Acid↗
PubMed1992

Pituitary-gonadal function during sleep in healthy aging men.

There is limited information on the relation between age-related changes in pituitary-gonadal function and sleep physiology in older men. In this cross-sectional study of 67 healthy volunteers free from sleep complaints, aged 45-75 yr, we (1) assessed peak fluctuations and hourly variations in plasma testosterone, LH and prolactin sampled every 20 min during sleep, and (2) explored the relation between sleep parameters, respiratory and periodic leg movement disturbances, and circulating concentrations of the aforementioned hormones. We hypothesized that alterations in sleep architecture or presence of sleep disorders may contribute to hormonal variations in aging subjects. Bioavailable testosterone decreased and LH increased with age, but there were no differences in total testosterone and prolactin and no major changes in peak hormonal release. There were positive associations, independent from the age effect, between sleep efficiency, decreased latency to onset of REM activity, and number of REM episodes, and circulating testosterone. Sleep-disordered breathing significantly increased with age. The degree of respiratory disturbance was associated with decreased overnight plasma bioavailable testosterone, but this relationship lost its significance after age-adjustment. The findings demonstrate a decrease in gonadal function during sleep in healthy aging men and suggest that changes in sleep efficiency and architecture are associated with alterations in gonadal activity in these older individuals.

Adult↗
PubMed1992

Bacillus methanolicus sp. nov., a new species of thermotolerant, methanol-utilizing, endospore-forming bacteria.

The generic position of 14 strains of gram-positive bacteria able to use methanol as a growth substrate was determined. All are obligately aerobic, thermotolerant organisms that are able to grow at temperatures of 35 to 60 degrees C. Nine of the strains produce oval spores at a subterminal-to-central position in slightly swollen rod-shaped cells. DNA-DNA hybridization studies, 5S rRNA sequence analysis, and physiological characteristics revealed that all 14 strains cluster as a well-defined group and form a distinct new genospecies. Analysis of the 16S and 5S rRNA sequences indicated that this new species is distinct from Bacillus brevis but closely related to B. firmus and B. azotoformans. The name proposed for this new species is B. methanolicus. The type strain, PB1, has been deposited in the National Collection of Industrial and Marine Bacteria as NCIMB 13113.

Bacillus↗
PubMed1992

Cell surface modifications induced by calcium ion in the myxobacterium Stigmatella aurantiaca.

Calcium ion induces in the myxobacterium Stigmatella aurantiaca the ability to glide on solid surfaces and to become cohesive (D. F. Gilmore and D. White, J. Bacteriol. 161:113-117, 1985; B. J. Womack, D. F. Gilmore, and D. White, J. Bacteriol. 171:6093-6096, 1989). The addition of calcium ion to the growth medium resulted in the formation of extracellular fibrils, the appearance in the membrane fractions of a 30-kDa protein, and the accumulation in a low-speed centrifugal pellet of 10 polypeptides that cross-reacted with affinity-purified antibody to one of the polypeptides. One of the polypeptides, a 55-kDa protein, was present in the membrane fraction of control cells not incubated with calcium ion and was apparently translocated to the extracellular matrix during incubation in medium containing calcium ion. The 55-kDa protein was immunologically related to a 65-kDa protein located on the fibrils of another myxobacterium, Myxococcus xanthus.

Bacterial Proteins↗