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Biomedical subjects

S M Hayes

Publications and source records attributed to S M Hayes.

18 recordsLinked to original sources
PubMed2001

Group 1 CD1 genes in rabbit.

CD1 is an Ag-presenting molecule that can present lipids and glycolipids to T cells. The CD1 genes were first identified in the human, and since then, homologs have been identified in every mammalian species examined to date. Over a decade ago, CD1B and CD1D homologs were identified in the rabbit. We have extended this earlier study by identifying additional CD1 genes with the goal of developing the rabbit as an animal model to study the function of CD1 proteins. We constructed a thymocyte cDNA library and screened the library with CD1-specific probes. Based on nucleotide sequence analyses of the CD1(+) cDNA clones obtained from the library, we have identified two CD1A genes and one CD1E gene as well as determined the complete sequence of the previously identified CD1B gene. The CD1E(+) cDNA clones lacked the transmembrane and cytoplasmic domains and, if translated, would encode for a soluble or secreted CD1E protein. In addition, expression studies demonstrated that the CD1 genes were expressed in peripheral lymphoid tissues as well as in skin, gut, and lung. Of interest is the finding that CD1A2, CD1B, and CD1E genes were found to be expressed by rabbit B cell populations. The rabbit, with a complex CD1 locus composed of at least two CD1A genes, one CD1B gene, one CD1D gene, and one CD1E gene, is an excellent candidate as an animal model to study CD1 proteins.

Amino Acid Sequence↗
PubMed1998

Maternity care practices of navy family practice residency graduates after leaving the military.

BACKGROUND: Nationwide, 32% of residency-trained family physicians deliver babies compared with 73% to 90% in the military. This study describes and defines issues that could ultimately help revive family practice maternity care. METHOD: We surveyed 112 family physicians who had left the navy. RESULTS: Ninety-one percent had delivered babies in the navy, 45% since leaving the military, and 25% currently. Principal maternity care incentives both in and out of the military were personal and professional satisfaction. Reasons for not providing civilian maternity care included malpractice risks, insurance costs, and lifestyle issues. The decision for providing maternity care was usually made before or during residency, whereas the decision against was most often made upon leaving the military. Among more recent graduates (1990-1995), 48% continued to deliver babies in civilian practice. (This is about 20% more than recent civilian graduates.) Malpractice concerns were less important to this group than to earlier graduates. CONCLUSIONS: Factors discouraging family physicians from providing maternity care arise from their practice environment and are not easily overcome with improved training and experience. Recent navy residency graduates are not as easily discouraged.

Adult↗
PubMed1997

The maternity care practice of Navy family practice residency graduates while on active duty.

BACKGROUND AND OBJECTIVES: Military family practice residency programs produce a high percentage of graduates who provide maternity care. This study will define the scope of maternity care practice for one military family practice residency program's graduates while they were serving on active duty in the U.S. Navy. METHODS: Two hundred eight surviving graduates of the family practice residency at Naval Hospital, Jacksonville, Florida, from 1971 to 1995 were surveyed by mail regarding their maternity care practice while on active duty. One hundred eighty-one (87%) responded to the survey, and the data were analyzed with descriptive statistics. FINDINGS: The vast majority of these Navy family practice residency graduates provided prenatal care (88.4%) and routine vaginal delivery services (85.1%) while on active duty. The majority repaired third- and fourth-degree perineal lacerations and performed vacuum- or forceps-assisted vaginal delivery. Additionally, a significant minority provided more advanced maternity care services such as dilation and curettage, tubal ligation, and cesarean section. The overwhelming majority (97%) of these graduates felt that their residency education had adequately prepared them to provide these maternity care services while on active duty. CONCLUSIONS: During the past 25 years, Navy residency-trained family physicians provided a wide range of maternity care services while on active duty and felt that their Navy residency training program had prepared them well to meet this responsibility.

Family Practice↗
PubMed1996

Role of IL-7 in the shaping of the pulmonary gamma delta T cell repertoire.

Gamma delta T cells bearing the canonical fetal-type V gamma 6/V delta 1 rearrangements are the predominant gamma delta T cells in the lungs of adult mice. In contrast, these V gamma 6/V delta 1 T cells are virtually absent in the pulmonary epithelia of nude mice. The intraepithelial dominance of gamma delta T cells that express this particular TCR is thought to result from a preferred thymic pathway of gene rearrangement and not from TCR-mediated positive selection. We now show that gamma delta T cell precursors in the lung epithelium of both euthymic and athymic neonatal mice generate this rearrangement in situ. In athymic mice, these clonotypes do not survive, but can be rescued in vitro and in vivo by the lymphokine IL-7.

Animals↗
PubMed1994

Localization of prothymocytes from wild-type and viable motheaten mice following intravenous injection into irradiated adoptive recipients.

Bone marrow cells from viable motheaten (me(v)) mutant mice fail to repopulate the thymus of irradiated recipients upon i.v. adoptive transfer. This defect can be corrected by the addition of wild-type marrow to the me(v)/me(v) marrow prior to i.v. injection. The present study focused on the nature of this apparent defect in me(v)/me(v) prothymocyte activity. We established an adoptive transfer assay system that facilitated the investigation of the migration patterns of wild-type and me(v)/me(v) marrow prothymocytes in adoptive recipients. Wild-type prothymocytes were found to seed the thymus of recipients as early as 1 day after i.v. injection. This early wave of prothymocyte seeding peaked at 4 days and diminished to undetectable levels at 6 days postinjection. After an interval of no detectable wild-type precursor activity in the thymus of primary recipients, a second wave of activity was observed on Day 15. This second wave resulted in permanent engraftment and persisted throughout the observation period. In contrast, only one initial wave of me(v)/me(v) prothymocyte seeding occurred in the recipient thymus. Detection of mev/mev precursors in the recipient's thymus was dependent upon the coinjection of wild-type marrow cells. These results suggest that me(v)/me(v) prothymocytes initially seed to the thymus of adoptive recipients, but fail to proliferate and/or differentiate due to a defect in marrow-derived intrathymic accessory cell activity.

Animals↗
PubMed1992

Thymic involution in viable motheaten (me(v)) mice is associated with a loss of intrathymic precursor activity.

Mice homozygous for the viable motheaten (me(v)) allele manifest abnormalities in thymocytopoiesis, are severely immunodeficient, and develop autoimmune disorders early in life. Premature thymic involution occurs in me(v)/me(v) mice, and their bone marrow prothymocytes are unable to repopulate the thymus of adoptive recipients following intravenous (i.v.) transfer. However, analysis of thymocytopoiesis following intrathymic (i.t.) adoptive transfer of bone marrow from me(v)/me(v) mice demonstrates the presence of normal numbers of prothymocytes. To investigate intrathymic development in me(v)/me(v) mice, we determined intrathymic precursor cell number and activity. Dual labeling analyses showed that an involuted me(v)/me(v) thymus is relatively enriched (fivefold) in CD4-CD8- thymocytes (intrathymic precursor phenotype) compared with wild-type (+/+) thymus. However, thymocytes from me(v)/me(v) mice were deficient in precursor activity when adoptively transferred i.t. into irradiated recipients. Thymocytes recovered from the involuted thymus of aged or steroid-treated normal mice also displayed reduced precursor activity. However, the phenotypic profile of thymocyte subsets from steroid-treated mice was enriched in single positive cells (mature phenotype) and was distinctly different from the subset distribution of thymocytes in me(v)/me(v) and aged mice. These results suggest that intrathymic precursor activity in me(v)/me(v) mice is decreased, and may be reflective of decreased prothymocyte seeding to the thymus in vivo. In addition, the results suggest that the thymic involution in me(v)/me(v) mice is not due solely to effects of corticosteroids.

Animals↗
PubMed1992

Evidence for elevated prothymocyte activity in the bone marrow of New Zealand Black (NZB) mice. Elevated prothymocyte activity in NZB mice.

New Zealand Black (NZB) mice spontaneously develop an autoimmune syndrome similar to that of systemic lupus erythematosus. Numerous abnormalities in T lymphocyte development have been reported in NZB mice, and the autoimmune syndrome can be adoptively transferred to naive recipients using bone marrow cells. In the present study, we have used an adoptive transfer system to study quantitatively the relative prothymocyte activity of marrow in either young (4-6 weeks of age) or older (8-10 months of age) NZB mice. Our results demonstrate that NZB marrow has approximately 7-fold more prothymocyte activity than that of marrow in SEA mice, a histocompatible, non-autoimmune prone normal strain of mice. This was ascertained by a competitive repopulation assay, in which mixtures of NZB and SEA prothymocytes were compared directly for their ability to repopulate the thymus of adoptive recipients. This increase in prothymocyte activity in the primary recipient of NZB marrow was associated with an increased competitive advantage of NZB marrow prothymocytes over that of SEA marrow prothymocytes in repopulating the hemopoietic (bone marrow) compartment of the primary host. These findings suggest that elevated prothymocyte activity in NZB mice, along with our previously presented evidence for abnormalities of thymocytopoiesis in NZB mice, may be important in their predisposition for autoimmunity.

Animals↗
PubMed1987

Enantiomeric composition analysis of amphetamine and methamphetamine by chiral phase high-performance liquid chromatography-mass spectrometry.

N-(Trifluoroacetyl)-l-prolyl- (N-TFA-l-prolyl-) d- and l-amphetamine diastereoisomers were separated by high-performance liquid chromatography and confirmed by an interfaced mass spectrometer system, using the commercially available N-3,5-(dinitrobenzoyl)phenylglycine chiral column. A separation factor of 1.52 and resolution of 3.8 were observed. N-TFA-l-prolyl-d- and -l-methamphetamine diastereoisomers were only partially resolved. The chiral stationary phase-solute interactions were studied by varying the mobile phase (2-propanol in hexane). Results indicate the separation mechanism proceeds via dipolar and hydrogen-bond interactions between the chiral stationary phase and the solute. A modified "dipole-stacking" model takes into account these interactions and explains the difference in separability observed for N-TFA-l-prolyl-d- and -l-amphetamine and N-TFA-l-prolyl-d- and -l-methamphetamine.

Amphetamine↗
PubMed1980

Regional associations: recent changes in blood services.

In this article, the authors describe the American Blood Commission's organizational and operational model of blood service regionalization, applied through the ABC's Regionalization Program. Explained are the criteria by which regional associations can obtain ABC "recognition," which acknowledges status as an approved regional association of blood service units.

Blood Banks↗
PubMedDate not supplied

Lichen planus--report of successful treatment with aloe vera.

Lichen planus is a disease that involves the skin and mucous membranes. It is characterized by unique eruptions. The cause of this disease is unknown, but has been linked to emotional stress, and has also been attributed to viral infections. A case is described of a successful treatment of lichen planus.

Aloe↗