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Biomedical subjects

M Wallace

Publications and source records attributed to M Wallace.

At least 145 records · Page 8Linked to original sources
PubMed1993

Effect of antiretroviral therapy on the cerebrospinal fluid of patients seropositive for the human immunodeficiency virus.

Elevated levels of beta 2-microglobulin and neopterin in cerebrospinal fluid (CSF) have been associated with neurologic complications of infection with the human immunodeficiency virus (HIV). The effect of zidovudine (ZDV) on these markers was assessed by studying the effect of ZDV treatment duration on CSF levels in a cohort of 145 HIV-positive men who were receiving ZDV. CSF beta 2-microglobulin and neopterin levels were significantly lower in those who had been taking ZDV for an intermediate period of time (46-365 days) than in those who had received ZDV either long term (> 365 days) or short term (1-45 days). CSF quinolinic acid levels were independent of duration of ZDV administration. A second CSF evaluation was available after 1 year for 54 HIV-positive men (19 of whom were also in the first cohort) and 11 HIV-negative controls. Patients who had started ZDV between lumbar punctures showed a significant decrease in CSF beta 2-microglobulin, but in those who had been receiving ZDV for > 1 year beta 2-microglobulin increased (p = 0.001). The effect was not observed with neopterin (p = 0.14). (Quinolinic acid levels were not studied longitudinally.) Finally, we observed that CSF levels of beta 2-microglobulin, neopterin, and quinolinic acid correlated strongly with each other in HIV-positive individuals (r = 0.7, p < 0.0001), even though ZDV might have different effects on these markers. In conclusion, we report that initiation of ZDV therapy is associated with a transient decrease in CSF levels of beta 2-microglobulin and neopterin.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

PREP. Almost there.

Explore the source record for details and available documents.

Education, Nursing, Continuing↗
PubMed1993

Induction of micronuclei in peripheral blood lymphocytes of patients treated for rheumatoid or osteo-arthritis of the knee with dysprosium-165 hydroxide macroaggregates or yttrium-90 silicate.

The advantages of radiation synovectomy, using preparations containing dysprosium-165 (Dy-165), over conventional materials based on yttrium-90 (Y-90) include a more ideal spectrum of decay energies, and a much shorter half-life permitting quicker and more efficient treatment. A new therapeutic agent, Dy-165 hydroxide macroaggregates, has been developed for the treatment of arthritis making use of these advantages. As part of a clinical trial of this material 42 patients were examined for micronucleus frequency in their peripheral blood lymphocytes prior to, and 2 weeks after, radiation synovectomy using Dy-165 hydroxide macroaggregates or Y-90 silicate. In the majority of patients from each treatment group no significant increase in micronucleus frequency was observed. This indicates that in these cases leakage of material from the site of treatment was not resulting in detectable irradiation of circulating cells irrespective of the choice of radiopharmaceutical. The maximum increase in micronucleus frequency observed corresponded to a radiation dose to circulating cells of approximately 0.3 Gray.

Adult↗
PubMed1992

Molecular analysis of neurofibromatosis type 1 mutations.

We have examined a panel of 115 unrelated NF1 individuals for mutation in the 3' region of the NF1 gene, using Southern blotting and polymerase chain reaction amplification of exons followed by single-strand conformation polymorphism (SSCP) analysis. We found only 2 unequivocal mutations: a 571 bp deletion which removed exon 6 and resulted in a frameshift in exon 7, and a 2 bp deletion in exon 1. A third sequence variation detected by SSCP was predicted to cause a lysine-arginine substitution in exon 6. This is a conservative change, and since the affected individual is a new mutation whose parents are not available, we cannot be sure of its biological significance. We detected mutations in at most 3% of individuals, from an analysis which covered 17% of the coding sequence by SSCP and a larger region by Southern blotting. This relative failure to detect mutations accords with the experience of others. Even allowing for the incomplete sensitivity of the methods used, the results suggest that the majority of NF1 mutations lie elsewhere in the coding sequence or outside it.

Base Sequence↗
PubMed1992

Pediatric transbronchial lung biopsy.

A retrospective review of 25 transbronchial lung biopsies in 19 pediatric patients is reported. Nineteen of these procedures used a rigid ventilating bronchoscope and a small cup biopsy forceps. The indications included diffuse pulmonary infiltrates in the immunocompromised patient, severe hyaline membrane disease, tumor, and lung transplant. In 84% of the procedures, adequate tissue was obtained. There was a 12.5% incidence of pneumothorax and no significant pulmonary hemorrhage.

Adolescent↗
PubMed1991

Investigation of varicella-zoster virus infection by polymerase chain reaction in the immunocompetent host with acute varicella.

A polymerase chain reaction (PCR) method developed to detect varicella zoster virus (VZV) in clinical samples is based on amplifying sequences of viral gene 31, the coding region for glycoprotein II. Its sensitivity was evaluated by amplification from plasmid VZV DNA containing VZV gene 31; 45 copies were detected in 1 microgram of human DNA. In testing within 24 h after the onset of varicella exanthem, 21 (75%) of 28 lesion samples were positive by VZV PCR, whereas VZV was isolated from only 21% by a standard tissue culture method. Only 1 (3.3%) of 30 samples of oropharyngeal secretions but peripheral blood mononuclear cells from 8 (67%) of 12 patients were positive. The sensitivity and specificity of the VZV PCR method indicates its usefulness for investigating the pathogenesis of VZV infection. Direct contact with cutaneous lesions rather than respiratory secretions may be the most important route of VZV transmission from healthy individuals with acute varicella.

Acute Disease↗
PubMed1991

Isotretinoin treatment alters steroid metabolism in women with acne.

The effect of isotretinoin (Roaccutane) on serum steroids and urinary steroid metabolites was investigated in seven female patients receiving the drug for treatment of severe acne over a 16-week period. Serum concentrations of dehydroepiandrosterone sulphate (DHAS), androstenedione (A2), and free androgen index (FAI) were not significantly altered. There was a significant fall in testosterone during treatment and a significant reduction in the 24 h urinary excretion of androsterone, tetrahydrocortisone (THE) and tetrahydrocortisol (THF) from week 8 onwards and for aetiocholanolone and allo-THF from week 12 (P less than 0.05). Although pretreatment levels of urinary steroid metabolites were not abnormal, the ratios of the 5 alpha/5 beta metabolites (androsterone:aetiocholanolone and allo-THF:THF) were at the upper limit of the reference range and were lowered after treatment, suggesting that 5 alpha-reductase activity is sensitive to isotretinoin.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1990

The human homolog of murine Evi-2 lies between two von Recklinghausen neurofibromatosis translocations.

Von Recklinghausen neurofibromatosis (NF1) is one of the most common inherited human disorders. The genetic locus that harbors the mutation(s) responsible for NF1 is near the centromere of chromosome 17, within band q11.2. Translocation breakpoints that have been found in this region in two patients with NF1 provide physical landmarks and suggest an approach to identifying the NF1 gene. As part of our exploration of this region, we have mapped the human homolog of a murine gene (Evi-2) implicated in myeloid tumors to a location between the two translocation breakpoints on chromosome 17. Cosmid-walk clones define a 60-kb region between the two NF1 translocation breakpoints. The probable role of Evi-2 in murine neoplastic disease and the map location of the human homolog suggest a potential role for EVI2 in NF1, but no physical rearrangements of this gene locus are apparent in 87 NF1 patients.

Animals↗
PubMed1990

Handedness as a function of sex and age in a large population of Lemur.

A population of 194 lemurs (Lemur spp.), 116 males and 78 females, from 1 to 30 years of age, was assessed for lateralized hand use in simple food reaching with a minimum of 100 reaches per animal. A hand preference was present in 80% of the population with a bias for use of the left hand that was most characteristic of male lemurs and young lemurs. The results confirm the presence of lateralization in prosimians, and we interpret the sex and age differences in relation to current theories of neural lateralization.

Aging↗
PubMed1988

Vasopressin neuropeptides and acquisition of heroin and cocaine self-administration in rats.

The effect of the vasopressin neuropeptide des-glycinamide (Arg8)-vasopressin (DGAVP) on reducing the acquisition of intravenous heroin self-administration in rats was analyzed. When rats reduced in body weight were allowed to self-administer heroin for 1 h per day in the presence of a fixed time, non contingent food delivery schedule, it appeared that heroin intake was related in an orderly way to the unit dose of heroin delivered. DGAVP decreased heroin intake during days 4 and 5 of acquisition, especially when a high dose of heroin was delivered. DGAVP decreased heroin intake more effectively when rats were tested without the food delivery schedule and for 6 h instead of 1 h sessions per day. Structure activity relationship studies revealed that the peptide (pGlu4, Cyt6)AVP-(4-8) was the shortest active sequence mimicking the effect of DGAVP and that this peptide was somewhat more potent than DGAVP in this respect. The peptide (pGlu4,Cyt6)AVP-(4-9) increased the heroin intake of the rats. DGAVP and (pGlu4,Cyt6)-AVP-(4-8) also decreased cocaine intake of body weight reduced rats given the opportunity to self-administer cocaine intravenously in daily 6 h sessions. It is concluded that vasopressin neuropeptides may decrease the reinforcing efficacy of heroin and cocaine during acquisition of drug self-administration rather than interact with nutritional and environmental factors influencing drug taking behavior.

Animals↗
PubMed1988

Differences in black and white adolescents' perceptions about cancer.

This study determined if black and white adolescents differed significantly in cancer knowledge, attitudes, and beliefs. Using the Health Belief Model, a 97-item questionnaire was developed by the researchers and completed by 573 black and 297 white junior and senior high school students from a large, midwest school district. Chi-square analyses yielded nine significant differences (p less than .01) between blacks and whites on cancer knowledge (etiology, warning signs, and prevention techniques). Further significant differences were found when items comprising the separate Health Belief Model subscales were analyzed. Blacks and whites differed significantly on cues to action (one item), perceived susceptibility (two items), perceived severity (one item), perceived barriers (two items), perceived benefits (three items), and interpersonal relationships (three items). Blacks and whites received cancer information from the same sources, with the exception of books, which was reported more by blacks.

Adolescent↗