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Biomedical subjects

M E Samuels

Publications and source records attributed to M E Samuels.

12 recordsLinked to original sources
PubMed1994

RNA binding by Sxl proteins in vitro and in vivo.

Sxl has been proposed to regulate splicing of specific target genes by directly interacting with their pre-mRNAs. We have therefore examined the RNA-binding properties of Sxl protein in vitro and in vivo. Gel shift and UV cross-linking assays with a purified recombinant MBP-Sxl fusion protein demonstrated preferential binding to RNAs containing poly(U) tracts, and the protein footprinted over the poly(U) region. The protein did not appear to recognize either branch point or AG dinucleotide sequences, but an adenosine residue at the 5' end of the poly(U) tract enhanced binding severalfold. MBP-Sxl formed two shifted complexes on a tra regulated acceptor site RNA; the doubly shifted form may have been stabilized by protein-protein interactions. Consistent with its proposed role in pre-mRNA processing, in nuclear extracts Sxl was found in large ribonucleoprotein (RNP) complexes which sedimented significantly faster than bulk heterogeneous nuclear RNP and small nuclear RNPs. Anti-Sxl staining of polytene chromosomes showed Sxl protein at a number of chromosomal locations, among which was the Sxl locus itself. Sxl protein could also be targeted to a new chromosomal site carrying a transgene containing splicing regulatory sequences from the Sxl gene, following transcriptional induction. After prolonged heat shock, all Sxl protein was restricted to the heat-induced puff at the hs93D locus. In contrast, a presumptive small nuclear RNP protein was observed at several heat puffs following shock.

Animals↗
PubMed1993

AIDS-related knowledge and attitudes of social workers in South Carolina.

This study examines the association between knowledge of acquired immune deficiency syndrome (AIDS) and skill among social workers in South Carolina and attitudes toward people with human immunodeficiency virus (HIV) and AIDS. A stratified random sampling method was used to obtain a representative sample of social workers in South Carolina. Findings show that AIDS-related knowledge and skill were significantly associated with improving the general attitudes of social workers toward HIV/AIDS clients. In addition to knowledge and skill-related measures, other significant covariates of attitudes include levels of contact with HIV/AIDS clients and sensitivity to minorities. As with previous studies, demographic variables such as age and gender were not found to be significantly related to variations in attitudes toward HIV/AIDS clients. Furthermore, locality of practice and supervisory position did not significantly correlate with attitudes. The implications of these findings for social services agencies are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Incentives for physicians to treat HIV-seropositive patients: results of a statewide survey.

We asked primary care physicians in South Carolina about their knowledge, attitudes, and beliefs regarding patients with human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS) and the services they provide for these patients. In support of an effort to develop more effective state policies regarding HIV/AIDS, the survey focused on conditions under which physicians would provide additional services for such patients; 597 of 900 physicians (66%) responded. Among responding physicians, 40% had not seen a patient with HIV infection/AIDS during the past year and 50% had seen only one to nine. Respondents identified lack of specialty backup support, insufficient clinical knowledge, and lack of available community services as the major barriers to providing care for these patients. Gaps in their knowledge included state and federal policies, available community resources, and clinical issues. Respondents said they would provide additional services if they had specialty backup (54%), better community and social support services (50%), additional training (46%), and limited liability (44%). We concluded that policy changes in these areas could expand access to care for HIV/AIDS patients in South Carolina.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Findings from a demonstration outreach project at a community health center.

Outreach using personal contact was a cornerstone of the federally funded Community Health Center (CHC) movement of the 1960s. Funding cuts and changes in federal policy have led to the discontinuation of this activity in most CHCs. This paper assesses aspects of a demonstration outreach project designed to encourage use of a CHC in Orangeburg, South Carolina. The evaluation shows that this type of outreach effort, which includes door-to-door canvassing, can identify specific needs for primary health care services in a poor underserved community, and can enhance community access to Medicaid, although the financial impact of bringing poor patients into CHCs by means of this type of outreach is relatively low.

Community Health Centers↗
PubMed1991

Single-use syringes.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1991

The complex set of late transcripts from the Drosophila sex determination gene sex-lethal encodes multiple related polypeptides.

Sex-lethal (Sxl), a key sex determination gene in Drosophila melanogaster, is known to express a set of three early transcripts arising during early embryogenesis and a set of seven late transcripts occurring from midembryogenesis through adulthood. Among the late transcripts, male-specific mRNAs were distinguished from their female counterparts by the presence of an extra exon interrupting an otherwise long open reading frame (ORF). We have now analyzed the structures of the late Sxl transcripts by cDNA sequencing, Northern (RNA) blotting, primer extension, and RNase protection. The late transcripts appear to use a common 5' end but differ at their 3' ends by the use of alternative polyadenylation sites. Two of these sites lack canonical AATAAA sequences, and their use correlates in females with the presence of a functional germ line, suggesting possible tissue-specific polyadenylation. Besides the presence of the male-specific exon, no additional sex-specific splicing events were detected, although a number of non-sex-specific splicing variants were observed. In females, the various forms of late Sxl transcript potentially encode up to six slightly different polypeptides. All of the protein-coding differences occur outside the previously defined ribonucleoprotein motifs. One class of Sxl mRNAs also includes a second long ORF in the same frame as the first ORF but separated from it by a single ochre codon. The function of this second ORF is unknown. Significant amounts of apparently partially processed Sxl RNAs were observed, consistent with the hypothesis that the regulated Sxl splices occur relatively slowly.

Amino Acid Sequence↗
PubMed1989

The Drosophila female-specific sex-determination gene, Sex-lethal, has stage-, tissue-, and sex-specific RNAs suggesting multiple modes of regulation.

For proper sexual development of females, the Sex-lethal (Sxl) gene must be activated early in development and remain on during the rest of the life cycle. Conversely, in males, Sxl must remain functionally off through development. Here, we show that the Sxl transcription unit spans a DNA segment of greater than 20 kb and encodes at least 10 distinct, but overlapping, RNA species. These RNAs range in size from 4.4 to 1.7 kb and exhibit sex, stage, and tissue specificity. Six RNAs, three female specific and three male specific, are first detected by midembryogenesis and persist through the adult stage: Their expression reflects the on/off regulation of Sxl's activity at the level of sex-specific alternate splicing. Four Sxl RNAs are found in adult females. Two of these RNAs are dependent on the presence of a functional germ line and may be relevant to Sxl's role in adult germ-line development. All four are present in unfertilized eggs. Finally, three Sxl RNAs are found only transiently during very early embryogenesis; we suggest that the expression of these RNAs may reflect an early regulation of Sxl at the level of transcription and that these transcripts are involved in the initial selection of the Sxl activity state in response to the primary sex-determination signal, the X/A ratio.

Animals↗
PubMed1984

Osteopathic physician location and specialty choice.

Physician distribution continues as a major national issue despite the projected oversupply of physicians by 1990. Kirksville College of Osteopathic Medicine (KCOM) in Kirksville, Missouri, has a high percentage of its graduates going into rural primary care. In this study of physicians who graduated from KCOM from 1930 to 1974, the authors sought to identify the factors influencing physicians to select rural primary care. The size of the physician's hometown, KCOM curricular experiences, and faculty role models were the most important factors influencing a physician to select rural primary care. While these findings are similar to other studies, this is the first to examine osteopathic medicine.

Career Choice↗
PubMedDate not supplied

Containing the spread of HIV infection: a world health priority.

The World Health Organization (WHO) estimates that the world total of AIDS cases will reach 300,000 by the end of 1988 and 500,000 to 3 million over the next 5 years. AIDS is of special concern to developing countries with their limited, stressed health care systems and the other serious health problems of their populations. Also, AIDS usually strikes the young and productive adults that the economies of these countries can least afford to lose. The Surgeon General of the Public Health Service has challenged the United Nations to make the world's blood supply safe by 1991. Private and public sector leaders could come together, apply the technology and resources available in industrialized countries, and achieve a victory in this facet of the AIDS pandemic. The WHO's global strategy has led to the establishment of national AIDS committees in 151 countries and the preparation of 70 short-term (6-12 months) plans and 25 medium-term (3-5 years) plans for national AIDS control programs.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

A rural-urban comparative study of nonphysician providers in community and migrant health centers.

This is a study of the employment of nonphysician providers--nurse practitioners, physician assistants, and certified nurse midwives--in both rural and urban Community and Migrant Health Centers and of factors associated with their employment, based on a 1991 national survey of 383 Centers. Results of the survey suggest that nonphysician providers, in particular nurse practitioners and certified nurse midwives, primarily serve as physician substitutes, and are more likely to be employed by Centers that are larger and have affiliations with nonphysician provider training programs. Rural or urban location is not significantly related to the employment of nonphysician providers after controlling for center size. The fact that rural centers employ fewer nonphysician providers than urban centers can primarily be accounted for by their relatively small size, rather than a lack of interest. These findings demonstrate that the use of nonphysician providers is an important way both to achieve cost containment and improve access to primary care for those residing in medically underserved areas.

Community Health Centers↗