Search PubMed⌕ Search

Biomedical subjects

M Young

Publications and source records attributed to M Young.

At least 199 records · Page 11Linked to original sources
PubMed1993

The site of antiviral action of 3-nitrosobenzamide on the infectivity process of human immunodeficiency virus in human lymphocytes.

The C-nitroso compound 3-nitrosobenzamide, which has been shown to remove zinc from the retroviral-type zinc finger of p7NC nucleocapsid proteins, inhibits acute infection of human immunodeficiency virus type 1 in cultured human lymphocytes. The attachment of the virus to lymphocytes and the activities of critical viral enzymes, such as reverse transcriptase, protease, and integrase, are not affected by 3-nitrosobenzamide. However, the process of reverse transcription to form proviral DNA is effectively abolished by the drug, identifying the mode of action of 3-nitrosobenzamide as interrupting the role of p7NC in accurate proviral DNA synthesis during the infectious phase of the virus life cycle.

Antiviral Agents↗
PubMed1993

Unusual lymphangioma observed prenatally in a 45,X fetus.

We present a case of a large frontal lesion, suspected on antenatal ultrasound to be a cephalocele. The cardiac anatomy was abnormal and fetal blood sampling showed a 45,X chromosome constitution. Postmortem examination proved this to be a lymphangioma and confirmed the presence of a cardiac defect. We suggest that this lymphangioma represents an unusual manifestation of monosomy X and discuss the importance of doing chromosome analysis in the presence of such a lesion which is of similar appearance as a cephalocele.

Adult↗
PubMed1993

Cause of death in multiple endocrine neoplasia type 1.

OBJECTIVE: Little data are available on the natural history of untreated multiple endocrine neoplasia type 1 (MEN-1). These data are essential in deciding treatment that may carry significant morbidity. We determined the causes of death in a large MEN-1 kindred with data available over a period of 130 years. Most cases were unrecognized as MEN-1 at the time of patient's death. DESIGN: Retrospective study of recorded medical data from 1861 to 1991. PATIENTS: One hundred fifty-nine deaths occurred, of which 46 were in individuals classified as "highly probable" of having MEN-1. RESULTS: Of 46 deaths in those classified as "highly probable" of having MEN-1, 20 (43.5%) died of a recognized complication of MEN-1 (12 of malignant neoplasms, six of renal calculi, and two of peptic ulcer). If accidental deaths are excluded, 50% of the deaths in patients with MEN-1 were the result of MEN-1, and the mean age of death (50.9 years)was significantly younger than that of other family members. CONCLUSIONS: It is concluded that MEN-1 leads to premature death, and that neoplasia rather than peptic ulcer disease is the main cause of death. Deaths from pituitary tumor or malignant endocrine tumors within the thorax were just as common or more common than deaths from pancreatic malignant neoplasms.

Adult↗
PubMed1993

A mutation (Met-->Arg) in the type I keratin (K14) gene responsible for autosomal dominant epidermolysis bullosa simplex.

We have identified a single base change in exon 4 of the type I keratin gene which results in the replacement of a methionine for an arginine residue at codon 272 in an Irish family displaying an autosomal dominant simplex (Koebner) form of epidermolysis bullosa (EB). This family had previously provided tentative evidence for linkage to genetic markers on chromosome 1q. The mutation cosegregates with the disease, producing a lod score of 4.8 at theta = 0.

Amino Acid Sequence↗
PubMed1993

Diverse mechanisms of control of aromatase gene expression.

The synthesis of estrogens from androgens is catalyzed by a microsomal cytochrome P450 termed aromatase (P450arom). The expression of this enzyme is highly regulated in both a developmental and cell-type specific fashion. We have chosen to examine the molecular basis of aromatase gene regulation by studying two models of aromatase expression: the Sebright bantam chicken and the R2C rat Leydig tumor cell line. In the first model, affected (Sebright) chickens express aromatase in many extragonadal tissues, while normal Leghorn chickens express aromatase only in the ovary and hypothalamus. Our studies have demonstrated that in normal chickens the site of transcription initiation is located approx. 147 nucleotides upstream of the initiator methionine. While Sebright animals also express aromatase mRNA initiated at an analogous initiation site in the ovary, a distinctive species of aromatase mRNA is also detected and is present in ovary and extragonadal tissues. This mRNA contains an identical coding sequence, but contains an alternatively spliced 5' noncoding exon that is derived from a distinctive promoter. The second model, the R2C Leydig tumor cell line, provides ample contrast. This cell line expresses high basal levels of aromatase (150-200 pmol/h/mg protein) that is suppressed with administration of 8 bromo cAMP or forskolin but the activity is not altered by glucocorticoids or epidermal growth factor treatment. Despite this distinctive pattern of regulation, at least three species of aromatase mRNA are detected in Northern blots, each of which is also detected in rat ovary. Primer extension and S1 nuclease assays indicate that both granulosa cells and R2C cells utilize a promoter that is located approx. 97 nucleotides upstream of the initiator methionine. These studies suggest that the "ovarian" promoter is evolutionarily conserved in both rats and chickens. These results further imply that the genetic mechanisms controlling the diversity of aromatase expression among tissues and among different species are likely to fall into two groups: those that employ distinctive promoters and alternative splicing and those that effect different patterns of regulation through a common ("ovarian") promoter.

Animals↗
PubMed1993

Parental evaluation of the Living Smart sexuality education program.

Parents completed 75 of 200 distributed questionnaires designed to elicit information about their perceptions of the Living Smart program, attitudes toward sexuality, and perceptions of their child's sexual behavior. Analysis indicated support for the course and provided additional information concerning parental support for the program and parental attitudes toward and perceptions of their own child's sexuality.

Adolescent↗
PubMed1993

Occurrence of craniosynostosis in neonates exposed to cocaine and tobacco in utero.

The occurrence of craniosynostosis (premature closure of cranial sutures) has been reported to be 3 to 5 per 10,000 live births. The incidence is even lower among African-American infants. The District of Columbia General Hospital serves primarily the African-American population with approximately 2000 deliveries a year. In the last 10 years, three neonates with craniosynostosis have been born at DC General Hospital; all three infants were African Americans. These infants were exposed to cocaine and tobacco in utero, which suggests a possible association between intrauterine cocaine and tobacco exposure and premature closure of cranial sutures. Possible pathogenesis of craniosynostosis in association with cocaine and tobacco use is discussed.

Adult↗
PubMed1993

[Manner of birth and otitis media].

BACKGROUND: There are many risk factors associated with the occurrence of otitis media; cesarean section could be one of them. REPORT: Two hundred and eighty four children were treated during the first three years of life by the same pediatric service. 47% of these children were treated for otitis media and 53% were not. 41% were delivered by cesarean section, and 59% were vaginal births. The incidence of otitis media in the cesarean section group was 0.504, versus 0.449 in the vaginal birth group. RESULTS: These data indicate that the fraction of risk of having otitis media that is attributable to cesarean section is 11%; the relative risk is 1.12. CONCLUSION: The observed effect is not large enough to confirm that cesarean section is a risk factor, but suggests that a carefully controlled prospective study should be conducted.

Cesarean Section↗
PubMed1993

Evaluating needle exchange: are there negative effects?

OBJECTIVE: We analyzed data on all drug-treatment admissions in San Francisco County over a 4-year period (n = 35,460) to evaluate the potential negative effects of the San Francisco needle-exchange program. METHODS: Admissions in the 2 years preceding implementation of the exchange program (1987-1988) were compared with admissions in the 2 years following implementation (1989-1990). RESULTS: No negative consequences of needle exchange were detected. Specifically, the presence of the exchange program was not associated with (1) increases in injection drug use, (2) increases in needle-sharing behavior, or (3) changing drug-use behavior from non-injection to injection. We also compared high-drug-use neighborhoods with and without local needle-exchange sites. Neighborhoods without needle-exchange sites showed a greater increase in proportion of admissions for injection drug use, and in frequency of injection, over time. CONCLUSIONS: Because of methodological limitations, our findings are preliminary. Longitudinal studies comparing needle-exchange and non-exchange cohorts are needed to further evaluate effects of this intervention.

Adult↗
PubMed1992

Purification and characterization of the mouse mammary tumor virus protease expressed in Escherichia coli.

The mouse mammary tumor virus (MMTV) protease gene was cloned into pGEX-2T, an Escherichia coli expression vector containing the glutathione S-transferase coding region of Schistosoma japonicum. The chimeric protein was formed by fusion of the glutathione S-transferase with a hexapeptide which contains a thrombin cleavage site, followed by the MMTV protease. Affinity chromatography on a glutathione-Sepharose 4B column was used to isolate the chimeric protein. After thrombin cleavage, the glutathione S-transferase and the protease were separated by gel filtration chromatography on a Sephadex G-75 column. The overall yield of the protease purification procedure was about 1 mg of protease/liter of culture, and the specific activity was 380 pmol/min.micrograms of enzyme. Like other retroviral proteases, the MMTV enzyme was active as a dimer, showed maximum activity at pH between 4 and 6, and could be inhibited by pepstatin A and a phosphinic acid derivative HIV-1 protease inhibitor. Enzymatic characterization of this protease reveals its broad specificity, showing a clear preference for the oligopeptide substrate mimicking the cleavage site at the amino-terminal end of the capsid protein (kcat/Km = 9725.5 M-1.s-1). The chimeric protein was also an active dimer and showed a similar Km (17 microM) for such an oligopeptide, although its kcat was about 10 times smaller. Autocatalytic processing of the MMTV protease was observed after expression of clones containing the natural cleavage site, as it occurs at the amino-terminal end of the viral protease, instead of the thrombin-sensitive sequence.

Amino Acid Sequence↗
PubMed1992

Mortality after coronary angioplasty and coronary artery bypass surgery (the national Medicare experience).

Mortality rates for Medicare patients who underwent coronary artery bypass surgery were compared with those who had angioplasty or angioplasty and bypass surgery. Two data sets were used for this study: The first contained information on demographic factors, co-morbidities and subsequent mortality on all 96,666 Medicare patients who had bypass surgery or angioplasty in 1985; the second contained additional detailed clinical data collected using the MedisGroups method on a random sample of 2,931 revascularization patients from 6 states. From the national data set 30-day and 1-year mortality rates were 3.8 and 8.2% for 25,423 angioplasty patients and 6.4 and 11.8% for 71,243 bypass surgery patients (p less than 0.001 for both time periods). Mortality rates for the MedisGroups data were 4.4 and 8.5% for the angioplasty patients and 6.5 and 11.9% for the bypass surgery patients. After eliminating patients admitted with a myocardial infarction, mortality rates were 1.9 and 6.0% for 632 angioplasty patients and 5.1 and 10.8% for 1,730 bypass surgery patients. The risk-adjusted relative risk of mortality for bypass surgery versus angioplasty was 1.72 (p = 0.001) for all patients, 2.15 (p less than 0.001) for low-risk patients and 0.90 (p = not significant) for high-risk patients. Results suggest that low-risk patients have better survival with angioplasty because of lower short-term mortality.

Angioplasty, Balloon, Coronary↗