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Biomedical subjects

M Powers

Publications and source records attributed to M Powers.

At least 55 records · Page 3Linked to original sources
PubMed1990

Long-term follow-up of a cohort of children with alpha-1-antitrypsin deficiency.

We assessed lung function, liver function, and smoking attitudes and behavior in 22 adolescents with homozygous alpha 1-antitrypsin deficiency whose condition had been detected through neonatal screening in the early 1970s. All subjects had normal lung volumes, expiratory flow rates, and diffusing capacity except for two siblings with mild asthma whose values reverted to the normal range after administration of an inhaled bronchodilator. Liver function was normal in all subjects with the exception of one boy who had an isolated elevation of alkaline phosphatase activity. Smoking attitudes, as determined by questionnaire, did not differ from those of 130 control subjects, but smoking initiation rates were significantly lower (p = 0.02). We believe that the issue of neonatal screening for alpha 1-antitrypsin deficiency should be reexamined because augmentation therapy for adults with emphysema is now available, and screening followed by family-based smoking intervention may lead to a nonsmoking life-style. The latter is especially important because the current weight of epidemiologic evidence strongly suggests that in nonsmokers with this condition, severe emphysema may never develop or, if it does, it will do so at a much later age than in smokers.

Adolescent↗
PubMed1989

Acceptance of the mental illness label by psychotic patients: effects on functioning.

Labeling theory predicts that psychotic patients who accept the label of mental illness will function less well than those who reject their diagnosis. Accepted psychotherapeutic theory suggests the reverse. Two predictive models were tested. Results supported the central hypothesis of the psychotherapeutic model but not that of the labeling model, although some elements of the latter model were affirmed. Besides acceptance of diagnosis, an internal locus of control appears important for good outcome in psychosis.

Adaptation, Psychological↗
PubMed1988

Appearance of venous malformations on magnetic resonance imaging.

The magnetic resonance (MR) imaging appearance of venous malformations, all angiographically verified, was evaluated in 11 patients. A venous malformation is characteristically depicted as a tubular area of decreased signal intensity in the white matter of the brain. In one patient, a histologically verified cavernous malformation was also present with a characteristic mixed signal-intensity core on the T2-weighted MR images. Care should be used when evaluating venous angiomas to exclude the presence of a lesion with associated prominent venous drainage, such as a glioma.

Brain Neoplasms↗
PubMed1986

Economics of notification and medical screening for high-risk workers.

Measuring the economic impact of notification and intervention programs for workers at high risk of disease from workplace exposure has been virtually nonexistent for several reasons, which will be discussed, and should include a comprehensive view of costs and benefits. A framework for analysis is proposed defining four major clients: the business community, workers and their families, the local and regional public sector, and the federal government. For each client, the positive and negative, quantitative and nonquantitative, direct and indirect, short-run and long-run effects are probed and a summary analysis is made. To illustrate the process, the notification and screening program conducted by the National Institute for Occupational Safety and Health and the Workers' Institute for Safety and Health, Augusta, Georgia, for workers exposed to beta-naphthylamine is described.

Cost-Benefit Analysis↗
PubMed1985

A double-blind comparative study of Estraderm and Premarin in the amelioration of postmenopausal symptoms.

Patients whose postmenopausal symptoms were being satisfactorily controlled with conjugated equine estrogens, either 0.625 mg/day (n = 57) or 1.25 mg/day (n = 67), participated in a study that compared the efficacy of these oral regimens with that of 17 beta-estradiol, 0.1 mg/day, administered through intact skin. The study was a multicenter, double-blind, randomized, parallel-group trial during which two thirds of the patients who received each dosage of conjugated equine estrogens were changed to an estradiol transdermal system while the remainder continued with conjugated equine estrogens. A total of 124 patients was included in the analysis of efficacy. The analysis revealed no significant differences between the estradiol transdermal system and conjugated equine estrogens in control of hot flushes or other postmenopausal symptoms and no statistically significant differences between treatment groups in regard to estrogen-related side effects. Minor topical reactions to the transdermal systems were reported during only about 20% of study weeks. Thus, transdermal estradiol, 0.1 mg/day, appears to be equally effective as conjugated equine estrogens, 0.625 or 1.25 mg/day, for controlling postmenopausal symptoms and is well tolerated.

Administration, Topical↗
PubMed1985

Multiple organ carcinogenicity of 1,3-butadiene in B6C3F1 mice after 60 weeks of inhalation exposure.

Groups of 50 male and 50 female B6C3F1 mice were exposed 6 hours per day, 5 days per week, for 60 to 61 weeks to air containing 0, 625, or 1250 parts per million 1,3-butadiene. These concentrations are somewhat below and slightly above the Occupational Safety and Health Administration standard of 1000 parts per million for butadiene. The study was designed for 104-week exposures but had to be ended early due to cancer-related mortality in both sexes at both exposure concentrations. There were early induction and significantly increased incidences of hemangiosarcomas of the heart, malignant lymphomas, alveolar-bronchiolar neoplasms, squamous cell neoplasms of the forestomach in males and females and acinar cell carcinomas of the mammary gland, granulosa cell neoplasms of the ovary, and hepatocellular neoplasms in females. Current workplace standards for exposure to butadiene should be reexamined in view of these findings.

Air Pollutants, Occupational↗
PubMed1985

The nucleotide sequence of the env gene from the human provirus ERV3 and isolation and characterization of an ERV3-specific cDNA.

The nucleotide sequence of the env gene of a previously described human provirus (ERV3) has been determined beginning near the 3'-end of the pol gene and continuing through the 3'-LTR. Analysis of the nucleotide sequence revealed the presence of a long open reading frame of 1944 nucleotides that is capable of encoding a polypeptide that has characteristics of other retroviral glycoproteins and transmembrane proteins. These include the presence of seven potential glycosylation sites, a typical glycoprotein-transmembrane protein cleavage sequence, and amino acid homologies to the glycoproteins and transmembrane proteins of other retroviruses. Further, we have isolated an ERV3-specific cDNA clone from a library prepared from liver RNA of a 20-week human fetus. DNA sequence analysis of this clone revealed that it is identical to the ERV3 genomic clone in the 1110 nucleotides that were sequenced.

Amino Acid Sequence↗
PubMed1982

Cytogenetic and flow cytometric studies of cells from patients with Fanconi's anemia.

Cells from patients wtih Fanconi's anemia are unusually sensitive to agents which are capable of crosslinking DNA. This increased sensitivity can be detected both by cytogenetic and flow cytometric methods. An elevated frequency of chromosome aberrations, which is further exaggerated by exposure of cells to DNA crosslinking agents, is a general feature of Fanconi's anemia. Information about the formation of sister chromatid exchanges in this disease is less consistent. Cytogenetic analysis of cells from patients with Fanconi's anemia can be compromised by a low mitotic index. This is reflected in an accumulation of cells In the G2 phase of the cycle, after exposure to the bifunctional alkylating agent, mitomycin C. New methods for differentiating individuals with Fanconi's anemia from unaffected individuals should be of empirical use and might also facilitate mechanistic studies of this disease.

Anemia, Aplastic↗
PubMed1978

Somatosensory-evoked potentials elecited by bilateral stimulation of the median nerve and its clinical application.

Somatosensory evoked potentials (SEPs) elicited by bilaterally simultaneous median nerve stimulation (BS) were studied in 28 normal subjects and in 20 patients with various cerebral lesions. In normals, SEP'S evoked by BS were symmetric between the homologous areas of the two hemispheres and resembled the response contralateral to unilateral stimulation (US). In patients with a cerebral lesion, BS responses were not only asymmetric but often differed in wave form from the response of the affected hemisphere to contralateral US. These alterations were attributed to the cumulative interactions of the anomalous contralateral and ipsilateral components. The additional use of BS made it possible to demonstrate SEP abnormalities that might have been regarded as normal or equivocal if only the US method had been used. The neurophysiologic mechanisms of the origin of SEP are discussed.

Adult↗
PubMed1977

Which patients respond to a mental health consumer survey.

Characteristics of patients at the Los Angeles County - University of Southern California Medical Center, Adult Psychiatric Outpatient Clinic who responded to a Los Angeles County voluntary "Client Satisfaction Survey" were compared with those who did not. Three significant differences consistently emerged. If an individual was a member of a minority group (black of Spanish surname), had less than a high school education, and was taking antispsychotic medication, his chance of returning a questionnaire to a waiting-room collection box was 79% as compared to the 30% chance of returning if he had none of these three characteristics. Younger patients had "Anglos" more often used the U.S. mail than the collection box to return the questionnaires. It is important that both methods be used to minimize bias. Most of the many patient-characteristics studied did not influence return rate. These findings are discussed in relation to the return method, ethnicity, medication, chronic mental illness, diminished freedom, and consumer voice in voluntary questionnaires.

Adult↗
PubMed1973

Adenosine 3':5'-cyclic monophosphate as a regulator of bacterial transformation.

Adenosine 3':5'-cyclic monophosphate added to exponentially growing cells of Hemophilus influenzae strain Rd increases competence for transformation 100- to 10,000-fold. Cyclic AMP added to near-stationary or stationary cells does not increase competence over the high level normally found in the early stationary phase.

Cyclic AMP↗