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Biomedical subjects

M R Wallace

Publications and source records attributed to M R Wallace.

At least 109 records · Page 6Linked to original sources

Tumor necrosis factor, interleukin-2, and interferon-gamma in adult varicella.

Adult varicella can be a severe illness complicated by pneumonia, encephalitis, or prolonged fever. This study measured levels of tumor necrosis factor (TNF)-alpha, interleukin-2 (IL-2), and interferon gamma (IFN-G) in a consecutive group of 31 adult varicella patients presenting within 24 hours of rash onset. All cytokines were assayed using an ELISA technique. TNF-alpha was detectable in 71% of patients with a mean level of 52 pg/ml. IL-2 was detectable in 29% with a mean level of 1040 pg/ml. IFN-gamma was detectable in only 9%. There was no correlation between TNF, IL-2, or IFN-G level and clinical severity as determined by duration and severity of cutaneous findings, duration of fever, frequency of hepatitis, or thrombocytopenia.

Acyclovir↗

Measles seroprevalence and vaccine response in HIV-infected adults.

Measles in HIV-infected patients can be a severe, even fatal, illness. The prevalence of measles seropositivity in HIV-infected adults and the durability of these antibody levels are uncertain. A prospective survey of 210 HIV-infected adults found that 95% of the adults had demonstrable antibodies using a standard ELISA technique. Seropositivity was no different in patients with CD4 counts over 400, from those with more advanced disease and CD4 counts under 200 (p = 0.8). Six seronegative patients were vaccinated and had serial antibody determinations: two of six (33%) patients had a durable positive antibody response at 1 year, and none had any observed toxicity. Vaccination of the identified measles-seronegative HIV-infected adults who are at high risk for measles is recommended, but a measurable antibody response may be expected in only a minority of cases.

AIDS-Related Opportunistic Infections↗

Detection of varicella-zoster virus DNA in air samples from hospital rooms.

Varicella-zoster virus (VZV) is a highly contagious infectious agent that causes outbreaks in institutional settings. Transmission of VZV is felt to occur following direct contact with an infected individual and by aerosol spread. To document the aerosolization of VZV, a polymerase chain reaction (PCR) assay was used to detect VZV DNA in air samples obtained from hospital rooms of patients with active VZV infection. VZV DNA was detected in 64 (82%) of 78 air samples from rooms housing patients with active varicella and 9(70%) of 13 samples from rooms of patients with herpes zoster. VZV was detected 1.2-5.5 m from patients' beds and for 1-6 days following onset of rash. On some occasions, VZV DNA could be detected outside the hospital isolation rooms housing patients. This PCR-based method allows the detection and semiquantitation of VZV aerosolization and can be a useful tool for monitoring efforts to control VZV aerosols in the environment.

Adolescent↗

Varicella immunity and clinical disease in HIV-infected adults.

Varicella is an infrequent but potentially severe infection in adult HIV-infected patients. We reviewed five cases of varicella in HIV-seropositive men; two were complicated by severe headache and meningismus, and one of these patients also had hepatitis and thrombocytopenia. All five patients responded well to acyclovir therapy, but one patient had dermatomal zoster 2 years later, and another failed to have detectable antibody after infection. We also performed a serosurvey on 181 consecutive HIV-infected patients presenting themselves for evaluation. A total of 95% of these patients had demonstrable antibody to varicella-zoster virus. Immune status to varicella did not correlate with the declining CD4 count, which was well preserved even in patients with fewer than 200 CD4 cells/mm3.

Adult↗

Highly resistant bacterial osteomyelitis in Somalia.

Chronic osteomyelitis is a major health problem in the aftermath of the conflict in Somalia. We studied the microbiology of chronic osteomyelitis among 30 patients in a large hospital in Mogadishu. Gram-negative bacteria were isolated from 77% of patients; most of these isolates were highly resistant to standard antibiotic agents but all were sensitive to ciprofloxacin, an oral fluoroquinolone antibiotic. Ciprofloxacin may prove useful in the management of chronic osteomyelitis due to highly resistant gram-negative bacteria.

Chronic Disease↗

Contribution of dialysis to endogenous oxalate production in patients with chronic renal failure.

We tested the possibility that the buffering agents in dialysis bath fluid might contribute to increased endogenous oxalate production in dialyzed patients. Using stable isotope dilution mass spectrometry, we obtained oxalate production rates and pool sizes directly for 10 patients in chronic renal failure, 5 of whom were undergoing continuous ambulatory peritoneal dialysis (lactate-buffered fluid). All peritoneal dialysis patients had either increased oxalate production rates or expanded oxalate pools when compared with undialyzed patients in renal failure. From a further four patients receiving maintenance hemodialysis we took blood samples immediately before and after three consecutive dialysis sessions in which the bath-fluid buffering agent (bicarbonate or acetate) was alternated; we analyzed these samples for oxalate and key precursors by capillary gas chromatography. Plasma glycine and serine concentrations remained within the physiological range. Glycolate and oxalate concentrations decreased, but the oxalate remained above normal after dialysis. All changes were independent of the bath-fluid buffering agent. We suggest that dialysis might stimulate the formation of oxalate by removing product inhibition of a late catabolic step.

Acetates↗

Linkage mapping in familial breast cancer: improved localisation of a susceptibility locus on chromosome 17q12-21.

Fifteen pedigrees with a total of 75 cases of breast cancer, 10 of ovarian cancer and 53 of other cancers have been collected. Polymorphic markers on chromosome 17q have been screened to locate a putative breast-cancer gene using DNA from relevant individuals within these families. Pairwise LOD scores have been calculated for markers CMM86, NM23, 42D6 and MFD188. The maximal summated LOD for the 15 families is 4.45 at theta = 0.025 using 42D6. All cases of bilateral breast cancer and ovarian cancer appear to be linked to this region. Recalculating LOD scores on the assumption of linkage in these cases increases the maximal summated LOD to 5.62 at theta = 0.025 using 42D6. A genetic exclusion map of critical recombinants in linked families suggests that the gene is flanked by markers 42D6 and MFD188, a region 5 to 10 cm in length.

Adult↗