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Biomedical subjects

J Dunn

Publications and source records attributed to J Dunn.

At least 163 records · Page 9Linked to original sources
PubMed1991

Familial breast cancer.

The genetic inheritance of familial breast cancer is complex and heterogeneous, i.e. it cannot be explained by one major susceptibility gene. It is likely that the chromosomal abnormalities and genetic lesions detected in the inherited syndromes will be implicated in the development of the more common sporadic breast tumours. Study of this important subgroup is essential to advance our understanding of the tumour biology of breast cancer and to develop adequate screening programmes for high risk young women.

Adult↗
PubMed1990

Diminished insulin sensitivity and increased insulin response in nonobese, nondiabetic Mexican Americans.

The contributions of diminished insulin sensitivity and decreased insulin response to the development of non-insulin-dependent diabetes mellitus (NIDDM) remain controversial. Nondiabetics in high-risk populations for NIDDM, including Pima Indians and Mexican Americans, are characterized by obesity and hyperinsulinemia relative to nondiabetics in the lower-risk white population. However, it is not clear to what extent diminished insulin sensitivity in the high-risk groups reflects obesity per se or is an inherent characteristic of these groups. Insulin sensitivity and secretion were determined in 10 nonobese, normoglycemic Mexican Americans (mean body mass index [BMI], 23.8 kg/m2) and 11 normoglycemic non-Hispanic whites (mean BMI, 22.5 kg/m2) using the intravenous glucose tolerance test (IVGTT) and the minimal model approach of Bergman et al. Age, BMI, sum of skinfolds, and the ratio of waist-to-hip circumference (WHR) were similar in both ethnic groups. Mexican Americans had decreased insulin sensitivity compared with non-Hispanic whites (4.06 +/- 0.72 in Mexican Americans v 7.56 +/- 1.13 in non-Hispanic whites, P = .017). The areas under the C-peptide and insulin curves were significantly greater in Mexican Americans than in non-Hispanic whites (P less than .01), suggesting greater insulin secretion in the former. This study provides evidence for diminished insulin sensitivity and increased insulin response in young, nonobese, normoglycemic Mexican Americans.

Analysis of Variance↗
PubMed1990

Effects of acute alcohol on penile tumescence in normal young men and dogs.

To determine the cause of the inhibition of sexual function observed in normal subjects with elevated blood alcohol concentrations (BAC), nocturnal penile tumescence (NPT) was monitored in 11 subjects over three consecutive nights. On the third night alcohol was administered (BAC = 0.154 g/100 mL). We observed no effect of alcohol on the size, duration, or number of erections. These results were confirmed in dogs. The latent period, magnitude, and duration of corpus cavernosal pressure changes produced by pelvic nerve stimulation were not affected by mean blood alcohol levels of 0.327 g/100 mL in three dogs. These results suggest that the inhibition of sexual response caused in conscious subjects by the ingestion of alcohol is not due to a suppression of the underlying spinal reflex but may be the result of its effect on perceptual or cognitive sexual mechanisms.

Adult↗
PubMed1990

The impact of steady-state cyclosporine concentrations on renal allograft outcome.

It has been reported that initial cyclosporine levels over 400 ng/ml posttransplantation result in an increased incidence of delayed graft function (DGF). Several studies have shown early graft function to be a major determinant for long-term graft survival. Continuous intravenous infusion (CIVI) has been employed to induce immunosuppression establishing therapeutic drug levels while minimizing toxicity in renal allograft recipients. This study examines the impact of the achieved serum CsA steady-state concentration (Css) levels upon transplant outcome in 228 patients given CsA by CIVI. In spite of administration of a specific drug dose, interindividual variation in elimination rates yields a broad range of Css levels. Six groups were stratified by CsA Css levels: group A 0-75 ng/ml, group B 76-100 ng/ml, group C 101-150 ng/ml, group D 151-200 ng/ml, group E 201-250 ng/ml, and group F greater than 250 ng/ml. Group A showed a significantly lower age and greater incidence of rejection at 0-10 days. Group F had significantly higher incidences of nephrotoxicity, hepatotoxicity, and delayed graft function. The findings suggest that the antirejection Css threshold for CsA may be at least 75 ng/ml, and the toxicity threshold above 250 ng/ml. Controversy exists about whether CsA influences the incidence of DGF, therefore risk factors for DGF were examined among the groups stratified by CsA Css levels. While cold ischemia time for all 228 patients as a group was highly correlated with DGF (P less than 0.001), neither cold ischemia time nor donor age was significantly different among the groups. There does appear to be a synergistic effect between CsA Css and CIT, since the incidence of DGF was significantly higher when the cold ischemia time was 21-24 hr and CsA Css greater than 200 ng/ml. Long-term graft function did not appear to be affected by early CsA Css levels. The Css of 100-250 ng/ml appears to achieve a satisfactory outcome with a 19.5% incidence of rejection within 10 days, 29.7% DGF, and 5.1% nephrotoxicity. Only 118/228 patients (52%) in this study achieved that range despite a fixed low CIVI of CsA. Thus potential renal allograft recipients may benefit from a pretransplant pharmacokinetic study to predict the proper CIVI dose.

Adult↗
PubMed1990

Causes of graft loss beyond two years in the cyclosporine era.

While CsA has improved renal-allograft survival rates in the first 2 years compared with Aza, Terasaki's multicenter study (1) failed to show any difference in long-term graft survival in CsA-Pred versus Aza-Pred-treated recipients. The present study examines the long-term graft-survival rates at a single center using CsA immunosuppression and seeks to discern the causes of 58 graft losses among 343 patients with functioning grafts beyond 2 years posttransplantation. The 6-year primary and cadaveric actuarial graft survival at this institution is 59% with a graft half-life of 10 years, which is better than the 40% and 7.7 years, respectively, reported by Terasaki (1) for primary cadaveric recipients on Aza-Pred. It is also better than the 41%, 6-year survival and 5.5-year half-life for primary cadaveric recipients treated with CsA-Pred as reported in the multicenter study. (1) Less experience with the use of CsA may explain the latter comparison. Primary LRD grafts at this institution (2/3 haploidentical) have a 6-year actuarial survival of 77% and a half-life very closely approximating that of HLA-identical LRD grafts under Aza (23.4 years). These results demonstrate that CsA mitigates the effects of HLA incompatibility to reduce graft survival. The most common cause of graft loss beyond 2 years was chronic rejection (36.2%) followed by noncompliance (27.6%). Patient deaths resulted in 13 of the 58 graft losses; most of the deaths were related to cardiovascular diseases. Only 3 patients died from causes that could be attributed to CsA immunosuppression; 2 from sepsis and 1 from viral hepatitis. Acute rejection caused 8.6% of the graft losses on continuous CsA therapy. When immunologic risk factors were analyzed, the entire graft-loss group had a significantly higher proportion of retransplant patients than the graft-survival group (P less than 0.005), suggesting that prior transplantation imposes a higher risk for graft loss not only acutely but long term as well. However, retransplanted patients were significantly less likely to lose their grafts because of noncompliance (P less than 0.005). Male patients were found to be significantly more noncompliant.

Adult↗
PubMed1990

Assessing the relationship between young siblings: a research note.

Methods for assessing the sibling relationship differ markedly, yet these have rarely been compared, or assessed in terms of retest reliability. We report an examination of sibling relationships as assessed by maternal interview, by videotaped observation in structured and semi-structured situations, and by naturalistic observation in unstructured settings. The different approaches to assessment were compared with data on 84 sibling pairs aged between 3 and 10 years. Test-retest reliabilities, assessed on 30 pairs studied on a second occasion, were good for maternal interview information, moderate for videotaped observations, and mixed for naturalistic observations. Independent positive and negative dimensions of the relationship were revealed by each method, and moderate agreement found between methods. Naturalistic observations of 30 minutes' duration were unsuitable for studying the negative aspects of the relationship.

Child, Preschool↗
PubMed1990

Police admissions to a psychiatric hospital. Demographic and clinical differences between ethnic groups.

Between October 1983 and December 1985, 268 patients were brought by police to a psychiatric hospital in south London under section 136 of the Mental Health Act 1983. Comparisons were made between 'blacks' and 'whites' on several clinical and demographic variables. The vast majority of admissions received a psychiatric diagnosis. An excess of black admissions was recorded. Black men were younger, were more likely than whites to be given neuroleptics, to be put on compulsory orders, and to be given an out-patient appointment when discharged from hospital. More black men were given a case-note diagnosis of schizophrenia or drug-induced psychosis. The differences in clinical management between ethnic groups could be at least partly accounted for by these differences in diagnosis. Treatment did not appear to be independent of diagnosis among the black admissions.

Adolescent↗
PubMed1990

All day drinking--its impact on an accident and emergency department.

In order to assess the impact of changes in the Licensing Laws in England, a prospective study was undertaken of patients attending the Accident and Emergency Department of the Newcastle General Hospital. Patients were breathalysed in October 1986, before the liberalisation of the Licensing Laws in England and Wales and again in October 1988, after this change. A blood alcohol level of greater than 50 mg/100 ml was detected in 13% of all attenders in 1986 and 14% in 1988. A comparison of the two years revealed no significant change in the number of patients who had ingested alcohol prior to attendance, although there was a trend towards increased frequency of alcohol ingestion in nighttime attenders.

Alcohol Drinking↗
PubMed1990

Prognostic factors in acute renal failure following aortic aneurysm surgery.

This study analyses the prognostic factors associated with survival in 70 patients who developed acute renal failure following surgery for an aortic aneurysm. Forty-nine patients (70 per cent) had surgery for a ruptured aortic aneurysm and 21 patients (30 per cent) had an elective procedure. Fifty-nine patients received haemodialysis. Thirty-three patients (47 per cent) survived the episode of acute renal failure. Six of these thirty-three patients died within three months of recovering from acute renal failure, giving an overall survival of 27/70 (39 per cent). A stepwise logistic regression analysis showed that the following factors significantly adversely affected survival: a need for inotropic support, ventilation for more than three days and age over 65 years. A model developed using these variables provided a basis for predicting outcome.

Acute Kidney Injury↗
PubMed1990

Medical experts compete to testify for malpractice plaintiffs.

This article describes the activities of physicians who offer their services for hire as witnesses and consultants to attorneys in malpractice litigation. Cases illustrating the extent of the problem are discussed along with legal and ethical restrictions on witnesses and contingent-fee payment of medicolegal consultants. A common belief is that the ever-present threat of malpractice litigation, which hangs over the heads of physicians like the sword of Damocles, is due to avaricious lawyers, unrealistic expectations of patients, and the reckless generosity of juries with other people's money. But physicians also have exacerbated a troublesome situation. Gone is the universal reluctance of doctors to testify against other doctors.

Ethics, Medical↗
PubMed1989

Serotonin uptake and configurational change of bovine pulmonary artery smooth muscle cells in culture.

Although it is well known that endothelial cells transport serotonin (5-HT) from extracellular to intracellular locations, it has been generally assumed that smooth muscle cells do not accumulate 5-HT but, rather, respond to 5-HT through a receptor activity unrelated to uptake of this amine or via stimulation of endothelial-derived relaxing factor. In the present study smooth muscle cells (PASMC), isolated and cultured from bovine pulmonary artery, were evaluated for 5-HT uptake under a variety of conditions. 5-HT uptake was linear up to 15 min and the rate was seven- to eightfold higher than that by bovine pulmonary artery endothelial cells. There was intracellular metabolism of 5-HT to 5-hydroxyindoleacetic acid (5-HIAA). The uptake was inhibited by exposure to 4 degrees C, absence of Na+ from the medium, and agents such as imipramine, verapamil, ketanserin, and methiothepin. Like that of endothelial cells, 5-HT uptake by PASMC was stimulated by exposure of cells to anoxia for 24 hr. Unlike endothelial cells that showed no morphological changes, PASMC at early passage showed dendritic formation after 30-60 min exposure to 5-HT at a concentration as low as 10(-8) M. Although this configurational change in response to 5-HT was lost with passage of cells, transport of 5-HT by these cells was retained. The configurational change was blocked by agents that inhibited 5-HT uptake, such as imipramine, verapamil, ketanserin, and methiothepin; it was unaffected by inhibitors of protein kinase C, phospholipase C, and calmodulin or absence of Ca2+ from the medium. We conclude that PASMC, as well as endothelial cells, accumulate 5-HT; there appears to be a close relationship between 5-HT uptake and configurational change of early passaged PASMC in culture. The factor(s) required for the configurational change are absent in endothelial cells and lost during passage of PASMC.

Animals↗
PubMed1989

A cross-language study of prosodic modifications in mothers' and fathers' speech to preverbal infants.

This study compares the prosodic modifications in mothers' and fathers' speech to preverbal infants in French, Italian, German, Japanese, British English, and American English. At every stage of data collection and analysis, standardized procedures were used to enhance the comparability across data sets that is essential for valid cross-language comparison of the prosodic features of parental speech. In each of the six language groups, five mothers and five fathers were recorded in semi-structured home observations while speaking to their infant aged 0;10-1;2 and to an adult. Speech samples were instrumentally analysed to measure seven prosodic parameters: mean fundamental frequency (f0), f0-minimum, f0-maximum, f0-range, f0-variability, utterance duration, and pause duration. Results showed cross-language consistency in the patterns of prosodic modification used in parental speech to infants. Across languages, both mothers and fathers used higher mean-f0, f0-minimum, and f0-maximum, greater f0-variability, shorter utterances, and longer pauses in infant-directed speech than in adult-directed speech. Mothers, but not fathers, used a wider f0-range in speech to infants. American English parents showed the most extreme prosodic modifications, differing from the other language groups in the extent of intonational exaggeration in speech to infants. These results reveal common patterns in caretaker's use of intonation across languages, which may function developmentally to regulate infant arousal and attention, to communicate affect, and to facilitate speech perception and language comprehension. In addition to providing evidence for possibly universal prosodic features of speech to infants, these results suggest that language-specific variations are also important, and that the findings of the numerous studies of early language input based on American English are not necessarily generalisable to other cultures.

Child, Preschool↗