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Biomedical subjects

D White

Publications and source records attributed to D White.

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

Predictive value of the ultrasensitive HIV viral load assay in clinical practice.

The aim of this study was to determine whether an HIV viral load of <50 copies/ml (c/ml), in the first available plasma sample to have shown a viral load of <400 c/ml, in patients on antiretroviral therapy, is correlated with longer term suppression of viral load (at <400 c/ml) compared to a viral load of 50-399 c/ml, and secondly, to compare the results obtained by ultrasensitive and standard viral load assays carried out on the same sample. A total of 98 HIV-positive patients on antiretroviral therapy with a viral load of <400 c/ml and at least one subsequent viral load measurement, were selected. For each patient, the first available specimen showing a viral load of <400 c/ml was tested using the Roche Amplicor ultrasensitive viral load assay, and patients were followed up subsequently for a median period of 52 weeks. Whether patients achieved an ultrasensitive viral load (USVL) of <50 c/ml or not made very little difference to the proportion of patients in each group showing continued response to treatment (52% vs. 45% respectively). The only variable that was shown to significantly predict longevity of response was the number of antiretroviral drugs used. Secondly, a standard viral load of <400 c/ml but with a detectable signal above background levels, was strongly predictive of a USVL of >50 c/ml. Overall, the findings suggest that the advantage in predictive value of the ultrasensitive over the standard HIV viral load assay, shown previously in clinical trials, may be limited in clinical practice.

Anti-HIV Agents↗
PubMed2000

Motivation and dietary self-care in adults with diabetes: are self-efficacy and autonomous self-regulation complementary or competing constructs?

This study examined constructs drawn from social-cognitive theory (A. Bandura, 1986) and self-determination theory (E. L. Deci & R. M. Ryan, 1985, 1991) in relation to dietary self-care and life satisfaction among 638 individuals with diabetes. A motivational model of diabetes dietary self-care was proposed, which postulates direct links between self-efficacy/autonomous self-regulation, and adherence/ life satisfaction. Structural equation modeling showed that both self-efficacy and autonomous self-regulation were associated with adherence (betas = .54 and .21, respectively) and with life satisfaction (betas = .15 and .34, respectively). Constraint analyses confirmed that self-efficacy was significantly more associated with adherence, whereas autonomous self-regulation was significantly more associated with life satisfaction. According to the model, interventions for dietary self-care and life satisfaction should focus on increasing self-efficacy and autonomous self-regulation.

Adult↗
PubMed2000

The prevalence of polycystic ovaries in women with a history of gestational diabetes.

OBJECTIVE: Women with a history of gestational diabetes mellitus (GDM) and women with polycystic ovary syndrome (PCOS) both demonstrate abnormalities in insulin action and secretion, and both are at increased risk of developing type 2 diabetes. To determine whether these similarities reflect a common pathophysiological basis, we examined the prevalence of ultrasound-based polycystic ovarian morphology in a large multiethnic group of women with a history of GDM and a group of women who had normal glucose tolerance during pregnancy. PATIENTS AND DESIGN: We studied 91 women with previous GDM (48 European, 20 South Asian, 10 Afro-Caribbean and 13 of other or mixed ethnicity) and 73 normoglycaemic control women (56 European, one South Asian, 14 Afro-Caribbean and two of other or mixed ethnicity), a median (interquartile range) of 20 (11-36) and 29 (17-49) months postpartum, respectively. A detailed history was taken, and the prevalence of PCO morphology on ultrasound scan was assessed. Fasting lipids, insulin, glucose status, gonadotrophins and testosterone were measured. Estimates of beta-cell function (%B) and insulin sensitivity (%S) were derived using the HOMA algorithm. RESULTS: Women with previous GDM had higher fasting glucose (5.4 (4. 8-6.0) vs. 4.7 (4.4-5.0) mmol/l, P<0.0001) and features reminiscent of syndrome X: higher BMI (26.4 (22.8-31.4) vs. 23.8 (21. 0-27.5) kg/m2, P = 0.002), waist/hip ratio (0.82 (0.79-0.88) vs. 0. 77 (0.73-0.81), P<0.0001), fasting insulin (165 (68-299) vs. 54 (24-156) pmol/l, P<0.0001), triglycerides (1.1 (0.8-1.6) vs. 0.8 (0.6-1.1) mmol/l, P<0.0001) and lower insulin sensitivity (%S) (27 (16-62) vs. 86 (34-139)%, P<0.0001) compared to control women. The prevalence of PCO was higher in the previous GDM group than in the control subjects (47/91 (52%) vs. 20/73 (27%), chi2 = 9.86, P = 0. 002 overall, odds ratio 2.7, P = 0.007 by logistic regression allowing for ethnicity). There was no difference in any metabolic parameter between the post-GDM PCO group and the post-GDM normal ovaries group, but irregular cycles were more prevalent in the PCO group (22/47 (47%) vs. 9/44 (21%), chi2 = 7.03, P = 0.008). CONCLUSIONS: We found a higher prevalence of polycystic ovarian morphology in women with a history of gestational diabetes. Among the women with previous gestational diabetes, irregular cycles were more prevalent in the PCO group than in the women with normal ovarian morphology, but no other differences in endocrine or metabolic parameters were detected. These findings confirm an association between PCO and gestational diabetes and suggest that women with gestational diabetes display metabolic abnormalities irrespective of ovarian morphology.

Blood Glucose↗
PubMed2000

Role of sperm sulfogalactosylglycerolipid in mouse sperm-zona pellucida binding.

Sulfogalactosylglycerolipid (SGG) is the major sulfoglycolipid of mammalian male germ cells. Like other sulfoglycolipids, SGG is believed to be involved in cell-cell/extracellular matrix adhesion. Specifically, we investigated whether sperm SGG played a role in sperm-egg interaction. Initially, we produced an affinity-purified, rabbit polyclonal immunoglobulin (Ig) G antibody that specifically recognized SGG (anti-SGG). Indirect immunofluorescence using anti-SGG IgG localized SGG to the convex and concave ridges and the postacrosome of the mouse sperm head. Pretreatment of sperm with anti-SGG IgG/Fab inhibited sperm-zona pellucida (ZP) binding in vitro in a concentration-dependent manner (to a maximum of 62%). This inhibition was observed at the level of primary binding. Sperm treated with anti-SGG IgG underwent the spontaneous and ZP-induced acrosome reaction at the same rate as control sperm treated with preimmune rabbit serum IgG. Fluorescently labeled SGG liposomes were shown to associate specifically with the egg ZP, whereas fluorescently labeled liposomes of galactosylglycerolipid (SGG's parental lipid) and phosphatidylserine (negatively charged like SGG) did not. Furthermore, coincubation of SGG liposomes with sperm and isolated ZP inhibited sperm-ZP binding in a concentration-dependent manner. These results strongly suggest an involvement of sperm SGG in direct binding to the ZP.

Acrosome Reaction↗
PubMed2000

Sedation of the mechanically ventilated patient.

Goals in the care of the mechanically ventilated patient are sedation, analgesia, anxiolysis, and muscle relaxation. Causes of distress in these patients include: pain, sleep deprivation, anxiety, psychosis, agitation, and delirium. Drugs used to alleviate these stressors are opiates, benzodiazepines, neuromuscular blocking agents, anesthetic induction agents, and inhalational agents. When caring for the agitated patient on the mechanical ventilator, physiologic, mechanical, and emotional causes must all be investigated. Finally, nonpharmacologic therapy is of utmost importance in the care of these patients.

Analgesics, Opioid↗
PubMed2000

Stroke associated with marijuana abuse.

We present the case of a 15-year-old with a cerebellar infarct that involved multiple arterial territories. It was temporally related to, and probably caused by, heavy marijuana use. While the mechanism of marijuana-associated stroke is unclear, the drug is known to cause hypotension and to impair peripheral vasomotor reflexes. We suspect that the child had diminished cerebral autoregulatory capacity and developed the stroke during a period of hypotension.

Adolescent↗
PubMed2000

Opportunistic testing for chlamydial infection in people attending a sexual medicine clinic for HIV tests.

Patients presenting for an HIV test alone represent an opportunity for screening for Chlamydia trachomatis. This audit was designed to assess the uptake of chlamydial screening by urinary ligase chain reaction (LCR) in adults attending a genitourinary clinic. All patients requesting an HIV test were offered full genital screening in the first audit period, if they declined they were offered chlamydial LCR. During the second period patients who refused full screening were asked to provide a urine sample for LCR testing unless they declined. Nine hundred and forty-two patients presented for HIV tests alone during the first audit period. Two hundred (22%) agreed to provide a urine sample for LCR testing, 7 (3.5%) were positive for chlamydia. During the second audit period 794 patients presented for HIV tests alone, 426 (55.1%) provided urine for LCR testing, 15 (3.4%) were positive. The uptake of urinary LCR, a non-invasive test for a potentially serious infection remained disappointingly low despite changes to the audit protocol. Reasons for this are discussed.

AIDS-Related Opportunistic Infections↗
PubMed2000

Distance learning: health education for ninth-grade students.

A telehealth programme for schools was established by staff at the East Carolina University schools of nursing, health education, social work, nutrition, education and medicine, in conjunction with the Eastern Area Health Education Center. A health education curriculum was developed for rural high schools using the North Carolina Information Highway for delivery. A Web page provided additional resources for teachers, teenagers and health professionals. Four telehealth sessions were conducted over three years: two with the pilot school and two with a second school on-line simultaneously. A total of 76 ninth-grade students completed the courses. Evaluation indicated successful outcomes in student learning. Respondents to a follow-up survey of members of the first telehealth class had positive comments about the experience. Utilization of the Web page increased steadily from 1997.

Education, Distance↗
PubMed2000

Primary dental care: time to revise the definition?

There have been several definitions of primary dental care over the last 20 years and while each was written to reflect the requirements of the time, most provide a conflicting description. This paper examines past definitions of primary dental care in the context of recent developments in UK dentistry and critically describes possible new definitions.

Comprehensive Dental Care↗
PubMed2000

Accuracy of screening mammography using single versus independent double interpretation.

OBJECTIVE: We conducted an analysis among 31 community radiologists to identify the average change in screening mammography interpretive accuracy afforded by independent double interpretation. MATERIALS AND METHODS: We assessed interpretive accuracy using a stratified random sample of test mammograms that included 30 women with cancer and 83 without. Radiologists were unaware of clinical information and of each other's assessments. We describe accuracy for individual radiologists and for double interpretation, including average sensitivity, specificity, diagnostic likelihood ratios positive and negative, and area under the receiver operating characteristic (ROC) curve. We also assessed weighted and nonweighted kappa statistics among all 465 pairs of radiologists and 31,465 pairs of unique pairs. The assessment for double interpretations used the "highest" (i.e., most abnormal) assessment of the two radiologists. We calculated the difference between each radiologist's individual accuracy and the average accuracy across that radiologist's 30 double interpretations. RESULTS: We found the following average accuracy statistics for individual radiologists: sensitivity, 79%; specificity, 81%; diagnostic likelihood ratio positive, 5.53; diagnostic likelihood ratio negative, 0.26; and area under the ROC curve, 0.85. The mean kappa statistic among radiologists for cancer cases increased with double interpretation from 0.59 to 0.70, and for noncancer cases from 0.30 to 0.34. Double interpretation resulted in an average increase in sensitivity of 7%, an average decrease in specificity of 11%, a decrease in diagnostic likelihood ratio positive of 2.35, a decrease in diagnostic likelihood ratio negative of 0.06, and an increase in area under the ROC curve of 0.02. CONCLUSION: Independent double interpretation does not increase accuracy as measured by the area under the ROC curve.

Adult↗
PubMed2000

Identifying local patterns of cross boundary flow and developing socio-economic profiles for general dental practitioners.

OBJECTIVES: The objective of this study was to assess cross-boundary flow in general dental practices in Dudley. DESIGN: Data were collected on NHS patients attending 57 general dental practitioners in Dudley Health District. Socio-economic data were attached to recognised postcodes in order to establish district of residence of patients and the socio-economic (ACORN) status of the neighbourhood in which they lived. SETTING: General dental practices in Dudley. SUBJECTS: General Dental Service patients. RESULTS: Using this methodology a profile of the patient population attending the participating practitioners was drawn up, giving an insight into patterns of dental attendance. CONCLUSION: These profiles will act as indicators of practices in which there are high levels of cross boundary flow and inform discussions on local commissioning.

Adolescent↗
PubMed2000

[Off-site and alternative services in community mental health care in Quebec].

The objective of this article is to understand the evolution of the practice of "elsewhere" and "otherwise" that alternative community resources in Québec have consistently advocated. Towards this end, we begin by identifying the meaning and significance of the ideas of "elsewhere" and "otherwise" in the context of the transformation of Quebec's mental health system since 1989. Then we present the results of an exploratory study carried out between 1997 and 1999 in which the coordinators as well as members of 6 community mental health organisations in a semi-urban region of Quebec were interviewed. The results of the study suggest the validity of certain fears that community resources are becoming "deradicalized." The analysis presented here suggests the unfolding of a complex process involving the integration of alternative resources into the broader public mental health system, internal dynamics, and the emerging limitations of the vision of "elsewhere" and "otherwise" that has guided them until now. Twenty years after alternative community resources appeared on the Quebec mental health scene, is it time to reform the philosophy of "elsewhere" and "otherwise"?

Community Mental Health Services↗
PubMed1999

Breast tumor characteristics as predictors of mammographic detection: comparison of interval- and screen-detected cancers.

BACKGROUND: Although mammographic screening is useful for detecting early breast cancer, some tumors are detected in the interval between screening examinations. This study attempted to characterize fully the tumors detected in the two different manners. METHODS: Our study utilized a case-control design and involved a cohort of women undergoing mammographic screening within the defined population of a health maintenance organization (the Group Health Cooperative of Puget Sound). Women were classified as having "interval" or "interval-detected" cancers (n = 150) if their diagnosis was made within 24 months after a negative-screening mammogram or one that indicated a benign condition. Cancers were classified as "screen detected" (n = 279) if the diagnosis occurred after a positive assessment by screening mammography. Tumors from women in each group were evaluated for clinical presentation, histology, proliferative characteristics, and expression of hormone receptors, p53 tumor suppressor protein, and c-erbB-2 protein. RESULTS: Interval-detected cancers occurred more in younger women and were of larger tumor size than screen-detected cancers. In unconditional logistic regression models adjusted for age and tumor size, tumors with lobular (odds ratio [OR] = 1.9; 95% confidence interval [CI] = 0.9-4.2) or mucinous (OR = 5.5; 95% CI = 1.5-19.4) histology, high proliferation (by either mitotic count [OR = 2.9; 95% CI = 1.5-5.7] or Ki-67 antigen expression [OR = 2.3; 95% CI = 1.3-4.1]), high histologic grade (OR = 2.1; 95% CI = 1.2-4.0), high nuclear grade (OR = 2.0; 95% CI = 1.0-3.7), or negative estrogen receptor status (OR = 1.8; 95% CI = 1.0-3.1) were more likely to surface in the interval between screening examinations. Tumors with tubular histology (OR = 0.2; 95% CI = 0.0-0.8) or with a high percentage of in situ components (50%) (OR = 0.5; 95% CI = 0.2-1.2) were associated with an increased likelihood of screen detection. CONCLUSIONS: Our data from a large group of women in a defined population indicate that screening mammography may miss tumors of lobular or mucinous histology and some rapidly proliferating, high-grade tumors.

Adult↗
PubMed1999

Laboratory model of a petroleum migration barrier in arctic alaska

Child's Pad is a gravel construction pad that was contaminated with petroleum during oil-field service operations in Deadhorse, AK. As part of a remedial action plan, a buffer strip of uncontaminated sandy gravel was placed along certain sections of the pad boundary. A peroxygen formulation manufactured by Regenesis Copyright, sold as Oxygen Release Compound (ORC(R)), was placed in the buffer strips. The ORC was intended to supply oxygen to aerobic microorganisms capable of degrading petroleum. Tests were conducted in a 1/2 scale laboratory cell to determine the oxygen release characteristics of the ORC when subjected to expected subsurface flow rates of up to 0. 02 l/s (6.9 m/day). In laboratory tests, a zone of enhanced oxygen concentration was formed down-gradient from the ORC socks. Only during periods when the flow rate was less than 0.01-0.015 l/s (3. 5-5.2 m/day) was ORC-oxygen observed at monitoring points up-gradient or directly cross-gradient of the ORC. Conclusions from the laboratory study were that ORC may provide an aerobic zone in the Child's Pad barrier as far as 1 m directly down-gradient of the sock during periods of high flows (6.9 m/day). Copyright 1999 Elsevier Science B.V.

Journal Article↗