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Biomedical subjects

S B Thomas

Publications and source records attributed to S B Thomas.

At least 19 recordsLinked to original sources
PubMed1991

Preparative separation and analysis of the enantiomers of [3H]Abbott-69992, an HIV anti-infective nucleoside, by ligand-exchange high-performance liquid chromatography.

Several chiral stationary phases (CSPs) were examined to separate the enantiomers of A-69992, a chiral HIV anti-infective nucleoside. The only CSP found to be effective was Nucleosil Chiral-1, a ligand-exchange CSP, which was used to prepare microgram amounts of the enantiomers of high optical purity. This appears to be the first separation of the enantiomers of a nucleoside by chiral high-performance liquid chromatography.

Antiviral Agents↗
PubMed1991

The Tuskegee Syphilis Study, 1932 to 1972: implications for HIV education and AIDS risk education programs in the black community.

The Tuskegee study of untreated syphilis in the Negro male is the longest nontherapeutic experiment on human beings in medical history. The strategies used to recruit and retain participants were quite similar to those being advocated for HIV/AIDS prevention programs today. Almost 60 years after the study began, there remains a trail of distrust and suspicion that hampers HIV education efforts in Black communities. The AIDS epidemic has exposed the Tuskegee study as a historical marker for the legitimate discontent of Blacks with the public health system. The belief that AIDS is a form of genocide is rooted in a social context in which Black Americans, faced with persistent inequality, believe in conspiracy theories about Whites against Blacks. These theories range from the belief that the government promotes drug abuse in Black communities to the belief that HIV is a manmade weapon of racial warfare. An open and honest discussion of the Tuskegee Syphilis Study can facilitate the process of rebuilding trust between the Black community and public health authorities. This dialogue can contribute to the development of HIV education programs that are scientifically sound, culturally sensitive, and ethnically acceptable.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Are health educators being prepared to provide HIV/AIDS education?: A survey of selected health education professional preparation programs.

Health education professional preparation programs were surveyed to determine the extent of HIV/AIDS education health educators are receiving. The survey also addressed content areas, skills being developed or enhanced, areas of deficiency in preparation programs, and areas in which national professional associations may assist in the preparation of AIDS educators. One hundred eight-three surveys were mailed; 114 (68%) were completed and returned. Twenty-one institutions reported planning a separate course on HIV/AIDS. Most were designing general service courses to reach a broad cross-section of students. Twenty-five institutions (23.8%) reported previously offering or currently offering a specific course on AIDS. One hundred two (89.5%) respondents reported HIV/AIDS warranted the attention and funding it had received. Thirty-seven (35.2%) respondents reported AIDS education was of sufficient importance to influence hiring of faculty members in their departments. Survey findings demonstrate that current AIDS education courses targeted to the general student population may not be adequate in meeting the professional preparation needs of health educators charged to provide AIDS education.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Community health advocacy for racial and ethnic minorities in the United States: issues and challenges for health education.

The 1985 Heckler report on Black and minority health clearly demonstrated that minority groups suffer excess morbidity and mortality directly related to social inequalities. Subsequently, improving the health status of minorities must go beyond personal health care delivery and address the broad issues of health policy. There is increasing evidence that wide public support is mounting to address many of the major health problems facing minority groups. In order to modify health behavior of minorities, health educators must recognize that traditional health promotion activities, focused on voluntary personal behavior change, may not be effective in reducing morbidity and mortality rates. Efforts to improve the health status of minorities must include an aggressive health policy dimension. Personal behavior change effort without an equal or greater emphasis on policy change is tantamount to blaming the victim. A health educators become increasingly aware of the political nature of health issues, it will be necessary to examine the health status of ethnic and racial minority populations from the perspective of community health advocacy.

Cause of Death↗
PubMed1989

Knowledge about AIDS and reported risk behaviors among black college students.

This study surveyed 975 undergraduates attending a large East Coast university during the spring semester of the 1987/88 academic year. A convenience sample of predominantly black students (94%) participated. Overall, knowledge of basic AIDS-related facts was satisfactory. Raw scores on the 25-item knowledge scale ranged from 7 to 25, with a mean of 20.5 (82%) and a mode of 22 (88%). Selected questions on how HIV is not transmitted, however, posed some problems for respondents. Less than 30% of respondents knew that the AIDs virus was not transmitted by insects; less than 80% knew that AIDS was not transmitted on toilet seats, through blood donations, kissing, and coughing. The survey also asked students whether they had ever engaged in certain behaviors that put them at risk of HIV infection. Approximately 17% of respondents had experienced anal intercourse, 6.5% reported use of heroin, 32.6% reported having had multiple sex partners, and 16% had been treated for a sexually transmitted disease. Students who reported engaging in high-risk behaviors had statistically significant lower mean knowledge scores than those who reported not engaging in those same high-risk behaviors. Results of the study support the need to increase efforts to deliver AIDS information specifically targeted to individuals who may be engaged in high-risk behaviors. Special health education programs must be designed to focus attention on risk behaviors (ie, unprotected anal intercourse) instead of risk groups (ie, homosexual and bisexual males).

Acquired Immunodeficiency Syndrome↗
PubMed1989

Serum osteocalcin and bone mineral metabolism following successful renal transplantation.

Serum osteocalcin (bone gla protein, BGP), a vitamin K-dependent non-collagenous bone protein and its relationship to other markers of bone and mineral metabolism were studied cross-sectionally in varying numbers of patients before and over 240 days following renal transplantation. Marked elevation of serum creatinine (11.9 +/- 0.76 mg/dl), osteocalcin (216.9 +/- 7 ng/ml), parathyroid hormone (PTH, mid-molecule fragment) (24.5 +/- 3.6 ng/ml), alkaline phosphatase (255.2 +/- 54.7 IU/l) and phosphorus (5.6 +/- 0.3 mg/dl) were noted preoperatively. Serum calcium levels remained normal throughout the study period while phosphate levels normalized within one week after transplantation. PTH levels progressively decreased postoperatively over the study period but were still elevated well above normal. Serum osteocalcin decreased to near normal values at 60-90 days after surgery. Both PTH and alkaline phosphatase correlated significantly with osteocalcin preoperatively and postoperatively. The relatively depressed values of osteocalcin in the face of still elevated PTH levels post-transplantation was attributed to the effect of immunosuppressive corticosteroid therapy. The significant correlation between PTH and osteocalcin suggests that osteocalcin may be as or more sensitive a measurement of bone turnover than alkaline phosphatase pre- and post-transplantation.

Adolescent↗
PubMed1988

Serum bone gla protein and the vitamin D endocrine system in the oophorectomized rat.

Because of the importance of estrogen in osteoporosis, the effects of decreased estrogen production using sensitive measurements of bone mineral metabolism were studied in oophorectomized rats. Serum levels of ionized calcium, bone gla protein (BGP), vitamin D metabolites (25-hydroxyvitamin D and 1,25-dihydroxyvitamin D), and estradiol were measured before and serially for 6 weeks after oophorectomy in the rat. In addition, static and dynamic indices of bone histomorphometry were determined after double tetracycline labeling. Fifty Sprague-Dawley female rats (approximately 250 g) were studied. Twenty-five rats underwent oophorectomy (O), while the remaining rats were sham operated. Estrogen deficiency was noted in the O group within a week after surgery (estradiol, 2.45 +/- 0.78 vs. 27.9 +/- 4.15 pg/ml; P less than 0.05). Serum ionized calcium levels, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and PTH levels did not differ between the two groups during the length of the study. Serum BGP levels were the same in both groups until the second week postoophorectomy, after which BGP remained significantly elevated in the O animals (121.7 +/- 5.95 vs. 76.7 +/- 3.87; P less than 0.001). Bone histomorphometry revealed increased osteoid volume (4.4 +/- 0.9% vs. 2.3 +/- 0.7%), osteoblast surface (26.5 +/- 2.4% vs. 3.2 +/- 1.2%), tetracycline surface (18.9 +/- 4.1% vs. 6.8 +/- 2.2%), as well as osteoclast surface (8.2 +/- 1.4% vs. 2.5 +/- 2%) in all O animals compared with those in the sham-operated group. These data indicate that oophorectomy and decreased estrogen result in increased bone turnover with elevated BGP levels. The marked BGP elevation within 2 weeks postoophorectomy suggests that estrogen withdrawal results in rapid altered bone mineral metabolism. The lack of concomitant increase in circulating PTH levels suggests that other factors may be mediating the bone loss following surgical oophorectomy.

Animals↗
PubMed1986

Serum bone gla protein (BGP) and other markers of bone mineral metabolism in postmenopausal osteoporosis.

Bone gla protein, the vitamin K-dependent protein synthesized by osteoblasts and measured in blood by radioimmunoassay, has been used as an index of the rate of bone turnover. The relationship of bone gla protein with other markers of bone mineral metabolism was determined in 31 untreated postmenopausal women with the osteoporotic syndrome. In addition to serum osteocalcin (BGP) we measured parathyroid hormone (PTH) (carboxyl and mid-molecule fragments), 25(OH)D, alkaline phosphatase, estradiol (E2), estrone (E1), dietary calcium intake, 24 hour urinary calcium excretion, and bone mineral density by CT scan of the lumbar vertebrae. Significant osteopenia was present on CT in untreated postmenopausal osteoporotic women (bone density in 18 out of 31 was below the critical value of 60 mg/cm3). Serum BGP correlated positively with CT scan (r + 0.647, P less than 0.001). CT and age were negatively correlated (r - 0.661, P less than 0.001) while CT and E2 showed a positive correlation (r + 0.554, P less than 0.01). Unexpectedly, BGP and age revealed a significant negative correlation (r - 0.421, P less than 0.05). These findings suggest a state of low bone turnover in this group with untreated postmenopausal osteoporosis.

Adult↗
PubMed1986

Tissue expansion: dividend or loan?

Epidermal mitotic activity during tissue expansion has been assessed in the guinea pig using tritiated thymidine and other confirmatory techniques. Implant inflation results in a threefold elevation of epidermal mitotic activity within 24 hours, followed by a gradual return to normal baseline over 2 to 5 days. Implant deflation, conversely, causes a transient decrease in epidermal mitotic activity. Neither of these phenomena has been previously described. It confirms previous animal studies which illustrate the highly responsive nature of the epidermis to physical stimuli and supports the view that tissue expansion is a highly useful manipulation of normal physiologic processes.

Animals↗
PubMed1977

The phospholipid-dependence of uridine diphosphate glucuronyltransferase. Phospholipid depletion and re-activation of guinea-pig liver microsomal enzyme.

More than 80% of the phospholipid component of guinea-pig liver microsomal membranes (prepared with 154mM-KCl) was removed by treatment with phospholipase A followed by extraction of the lysophosphatides and fatty acids produced with albumin. Delipidation strongly inactivated the highly active UDP-glucuronyltransferase of these preparations and activity was restored by mixtures of phosphatidylcholine and lysophosphatidylchlone. However, small quantities of lysophosphatides were still associated with the delipidated fractions after extraction with albumin and might have influenced the inactivation and re-activation observed. To eliminate these uncertainties, microsomal proteins and phospholipids were separated by gel filtration on Sephadex G-150 in the presence of cholate. This technique also strongly inactivated the enzyme but did not generate membrane-active phospholipid degradation products. High transferase activity was again restored to the delipidated protein by choline glycerophosphatides. These results confirm the view that the fully active form of microsomal UDP-glucuronyltransferase is phospholipid-dependent.

Animals↗