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Biomedical subjects

C White

Publications and source records attributed to C White.

At least 145 records · Page 8Linked to original sources
PubMed1997

Mismatches for two major and one minor histocompatibility antigen correlate with a patient's rejection of a bone marrow graft from a serologically HLA-identical sibling.

We describe the case of a patient with chronic myeloid leukemia who rejected a bone marrow (BM) graft from a sibling donor believed to be HLA identical. Sequencing of the HLA genes showed the mother to be heterozygous for two closely related HLA haplotypes that could not be resolved by serological typing. The donor and the recipient had each inherited a different maternal haplotype resulting in allelic mismatches for the HLA-B35 and the HLA-DR11 genes. T cell cytotoxicity directed towards the donor's B35 allele was detected in the patient, in addition to CTL specificity for an HLA-B7-restricted minor histocompatibility antigen carried by the donor, resulting in three histocompatibility mismatches between the BM donor and the recipient.

Adult↗
PubMed1996

A comparison of carbon/energy and complex nitrogen sources for bacterial sulphate-reduction: potential applications to bioprecipitation of toxic metals as sulphides.

Detailed nutrient requirements were determined to maximise efficacy of a sulphate-reducing bacterial mixed culture for biotechnological removal of sulphate, acidity and toxic metals from waste waters. In batch culture, lactate produced the greatest biomass, while ethanol was more effective in stimulating sulphide production and acetate was less effective. The presence of additional bicarbonate and H2 only marginally stimulated sulphide production. The sulphide output per unit of biomass was greatest using ethanol as substrate. In continuous culture, ethanol and lactate were used directly as efficient substrates for sulphate reduction while acetate yielded only slow growth. Glucose was utilised following fermentation to organic acids and therefore had a deleterious effect on pH. Ethanol was selected as the most efficient substrate due to cost and efficient yield of sulphide. On ethanol, the presence of additional carbon sources had no effect on growth or sulphate reduction in batch culture but the presence of complex nitrogen sources (yeast extract or cornsteep) stimulated both. Cornsteep showed the strongest effect and was also preferred on cost grounds. In continuous culture, cornsteep significantly improved the yield of sulphate reduced per unit of ethanol consumed. These results suggest that the most efficient nutrient regime for bioremediation using sulphate-reducing bacteria required both ethanol as carbon source and cornsteep as a complex nitrogen source.

Acetates↗
PubMed1996

Prevalent vertebral deformities: relationship to bone mineral density and spinal osteophytosis in elderly men and women.

The aims of this study were to ascertain vertebral deformity prevalence in elderly men and women and to describe the association between bone mineral density (BMD) at the lumbar spine and femoral neck, severity of spinal degenerative disease and vertebral deformity prevalence. We performed standardized spinal radiographs in a random sample of 300 elderly men and women participating in the Dubbo Osteoporosis Epidemiology Study, a population-based study of fracture risk factors. Radiographs were read independently by masked observers for the prevalence of vertebral deformity and severity of osteophytosis. BMD was measured by dual-energy X-ray absorptiometry. The prevalence of vertebral deformities was critically dependent on the criterion used. The less strict criteria seemed to overestimate deformities at either end of the spine region analysed. However, irrespective of the criterion used, prevalence of deformity was higher in men than in women (25% vs 20% for the 3 SD criterion, 17% vs 12% for the 4 SD criterion and 27% vs 25% for the 25% criterion). Femoral neck BMD was more strongly associated with vertebral deformities than spinal BMD for the 25% criterion (OR/SD change in BMD 1.39 (p = 0.02) vs 1.20 (p = 0.19)), 3 SD criterion (OR/SD change in BMD 1.45 (p = 0.01) vs 1.10 (p = 0.34)) and 4 SD criterion (OR/SD change in BMD 1.98 (p = 0.0002) vs 1.68 (p = 0.008)). BMD was also more strongly associated with biconcave deformities than either wedge or crush deformities and more so in men than in women. Severity of spinal osteophytosis was not associated with vertebral deformity. In conclusion, femoral neck BMD is at least equivalent to the lumbar spine BMD in strength of association with prevalent vertebral fractures. Spinal osteophytosis falsely elevates BMD without a concomitant decrease in fracture risk, indicating that any interpretation of spinal BMD needs to be adjusted for osteophytosis. These findings support the use of femoral neck bone densitometry in older men and women. Moreover, these data indicate that current criteria for radiological assessment of vertebral deformity are sufficiently loose to include a substantial proportion of non-fractures in the elderly, with important implications for the design of clinical trials. However, irrespective of the criterion used, vertebral deformities in men are at least as common, if not more so, than in women, suggesting that vertebral osteoporotic fractures are overlooked in men.

Absorptiometry, Photon↗
PubMed1996

A cost-effectiveness evaluation of laparoscopic disposable versus nondisposable infraumbilical cannulas.

STUDY OBJECTIVE: To compare the safety and cost-effectiveness of disposable and nondisposable infraumbilical laparoscopic cannulas. DESIGN: Retrospective review of consecutive laparoscopic procedures performed from July 1, 1988, to June 30, 1994. SETTING: A university-affiliated hospital. Patients. The 10,459 consecutive women who underwent laparoscopies. INTERVENTIONS: A 10-mm disposable cannula was used in 529 laparoscopies and a nondisposable cannula in 9930, based on physician preference. MEASUREMENTS AND MAIN RESULTS: The only intraabdominal injuries associated with insertion of disposable and nondisposable cannulas were bowel injuries in one and three patients, respectively. The injury rates for the instruments were 19 and 3/10,000 cases, respectively, but were not statistically different (P <0.05, Fisher's two-tail exact test). The hospital cost per disposable cannula in 1994 was $63.71; the cost per procedure with the nondisposable cannula was amortized and was less than $1.35, including maintenance. CONCLUSION: Disposable cannulas were not cost effective and were associated with a higher but not statistically significant complication rate. Therefore, the more expensive disposable cannulas are not recommended.

Catheterization↗
PubMed1996

A cost analysis of endometrial ablation, abdominal hysterectomy, vaginal hysterectomy, and laparoscopic-assisted vaginal hysterectomy in the treatment of primary menorrhagia.

STUDY OBJECTIVE: To assess the cost of four procedures performed to treat primary menorrhagia. DESIGN: Retrospective analysis. Setting. A 394-bed womens' teaching hospital. PATIENTS: Eighty healthy women undergoing one of the four procedures. Interventions. The study patients were equally divided among vaginal hysterectomy (VH), total abdominal hysterectomy (TAH), laparoscopic-assisted vaginal hysterectomy (LAVH), and endometrial ablation (EA). MEASUREMENTS AND MAIN RESULTS: Endometrial ablation was associated with significantly reduced hospital costs and a shorter recovery period than the other modalities. Hospital costs were less for VH and return to work was quicker after LAVH and VH. This study did not evaluate long-term failures or complications unless they occurred within the first 2 months after the procedure. CONCLUSION: Among women who could be treated by any of these techniques, VH was significantly more cost effective for the permanent management of primary menorrhagia than LAVH and TAH. The cost efficiency of EA was clearly implied, but further studies must be completed to evaluate the long-term costs associated with treatment failures. Although physicians should not choose a procedure based exclusively on cost, the expense of a less efficient or more costly procedure may affect a hospital's competitiveness in this era of managed care.

Cost-Benefit Analysis↗
PubMed1996

Management and outcome of pneumothoraces in patients infected with human immunodeficiency virus.

To better understand the natural history, management, and outcome of pneumothoraces in HIV-infected patients, we reviewed hospital charts and chest radiographs of HIV-infected adults discharged from the University of Maryland Medical Center over a 6-year period. Sixty pneumothoraces occurred in 39 patients. Twenty-three pneumothoraces resulted from trauma and 37 were spontaneous. Thirty-two (86%) of the spontaneous pneumothoraces occurred in patients with Pneumocystis carinii pneumonia (PCP). Eight percent of the traumatic pneumothoraces in patients who did not have PCP resolved. Patients who had pneumothorax as well as PCP were more difficult to manage and had a poorer outcome (50% mortality) than those who did not have PCP (25% mortality).

Adult↗
PubMed1996

Alzheimer's disease and its Lewy body variant: a clinical analysis of postmortem verified cases.

OBJECTIVE: The authors compared clinical findings of Alzheimer's disease and the so-called Lewy body variant of Alzheimer's disease. METHOD: Available data were analyzed on the clinical features of 58 patients with Alzheimer's disease and 24 patients with the Lewy body variant of Alzheimer's disease who underwent postmortem examination. RESULTS: The proportion of men was significantly larger in the Lewy body variant group than in the Alzheimer's disease group (66.7% versus 34.5%), and, concordantly, the Lewy body variant group was slightly taller. The prevalence of hallucinations and delusions was significantly higher in Lewy body variant subjects than the Alzheimer's disease subjects, but there were no significant differences between the two groups in educational attainment, family history of dementia, age at onset, duration of illness, cognitive impairment, overall severity of illness, or neuropsychological findings. Patients with the Lewy body variant of Alzheimer's disease tended to experience more frequent extrapyramidal side effects of neuroleptics than did the patients with Alzheimer's disease, but for patients in the two groups who were not exposed to neuroleptics, there was little difference in frequency of extrapyramidal side effects. CSF concentration of homovanillic acid (HVA) was significantly lower in the Lewy body variant patients, even when correction was made for height. CONCLUSIONS: The Lewy body variant of Alzheimer's disease may be suspected in elderly male dementia patients who otherwise meet criteria for Alzheimer's disease but who manifest significant psychiatric symptoms and neuroleptic-induced extrapy-ramidal side effects and have low levels of CSF HVA.

Aged↗
PubMed1995

Voluntary anonymous linked study of the prevalence of HIV infection and hepatitis C among inmates in a Canadian federal penitentiary for women.

OBJECTIVE: To determine the seroprevalence of HIV infection and hepatitis C among inmates of a federal penitentiary for women. DESIGN: Voluntary, anonymous, linked, point-prevalence study involving testing of blood samples for antibodies to HIV and hepatitis C virus. PARTICIPANTS: All inmates of the multilevel security federal Prison for Women, Kingston, Ont., who volunteered to participate in the study. Inmates at this long-stay facility are from across Canada. OUTCOME MEASURE: Seroprevalence rate among participants of antibodies to HIV and hepatitis C virus. RESULTS: Of the 130 inmates available for study 113 (86.9%) agreed to donate a blood sample. One woman (0.9%) was HIV positive; 45 (39.8%) were positive for hepatitis C antibody. CONCLUSIONS: It is possible to obtain a high participation rate in a voluntary, anonymous, linked point-prevalence study in a long-stay penitentiary. The HIV seroprevalence rate of 0.9% is lower than that found in studies in provincial (short-stay) prisons. However, the high rate of antibodies to hepatitis C suggests a significant level of risk behaviour, most likely injection drug use, and suggests the potential for a rapid increase in the rate of HIV infection should the number of newly admitted HIV-positive inmates who use injection drugs rise.

Adolescent↗