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Biomedical subjects

L Saunders

Publications and source records attributed to L Saunders.

At least 19 recordsLinked to original sources
PubMed2001

An investigation of condom use by frequency of sex.

OBJECTIVES: To examine the association between condom use and frequency of sex across sexual partner types. METHODS: Data were collected from African American drug users residing in Washington, DC. Participants were asked to provide the first name of the last three partners with whom they had had vaginal sex, to define the type of relationship, the number of times they had had vaginal sex in the last 30 days with each partner, and whether they had used a condom during their last sexual encounter with each partner. Condom use was examined by frequency of sex in the past 30 days controlling for partner type. RESULTS: Frequency of sexual encounters varied by partner type. The largest number of sexual encounters was with casual partners, followed by commercial and primary partners, respectively. Within partner types, participants had sex most frequently with primary partners. Condom use was lowest within primary partner relationships. Regardless of partner type, condom use varied consistently depending on the frequency of sex with the same partner. CONCLUSIONS: Condom use is related to the frequency of sex between partners when partner type is controlled. The association between frequency of sex and condom use is independent of partner type, suggesting that partner type may become less influential in determining condom use as the frequency of sex increases. This finding suggests that contextual factors determining condom use go beyond partner type designations and include other relationship variables.

Adult↗
PubMed1999

Predictors of in-hospital mortality following operative management of hip fractures.

OBJECTIVE: To identify predictors of in-hospital mortality and hospital stay following hip fractures. DESIGN: Retrospective cohort study of 185 consecutive patients. SETTING: Tertiary Care University Hospital. PARTICIPANTS: Individuals requiring operative treatment of a proximal femoral fracture excluding those individuals < 50 years old, with femoral head or subtrochanteric fractures, and significant co-morbidity. OUTCOMES: In-hospital mortality and length of hospital stay (days). RESULTS: 116 patients met the inclusion criteria. Predictors of in-hospital mortality from logistic regression analysis included male gender (odds ratio with 95% CI: 5.5, 1.5-20.5), admission from a long term care facility (5.5, 1.4-22.6), age greater than 90 years (4.5, 0.9-22.1), and living at home with support (0.2, 0.03-0.9). Predictors of hospital stay from multivariate regression analysis in order of magnitude included presence of a post-operative complication (odds ratio with 95% CI: 14.1, 4.7-44), living at home with support (3.4, 1.3-8.9) and older age (> 85 years) (2.7, 1.0-7.3). Moreover, confusion, urinary tract infections and decubitus ulcers accounted for greater than 50% of all complications encountered. A trend between the number of positive predictors and length of hospital stay was observed. CONCLUSIONS: Elderly individuals admitted from a long term care facility are at high risk of mortality following operative fixation of hip fractures. Early recognition and aggressive management of post-operative complications such as confusion, urinary tract infections and decubitus ulcers through careful patient monitoring may decrease hospital stays in those that survive.

Aged↗
PubMed1998

The acceptability of a computer HIV/AIDS risk assessment to not-in-treatment drug users.

The purpose of this paper is to report the results of a study assessing the acceptability of a computer HIV risk assessment instrument administered to not-in-treatment drug users. The study asked three questions related to acceptability: (1) are drug users comfortable responding to HIV risk questions using the computer assessment; (2) do drug users feel that they possess the requisite skill to respond to questions using a computer; and (3) do drug users believe that the responses they provide using the computer assessment will remain private and confidential. This study differs from other assessments of the acceptability of computer assisted data collection in that the population of interest has only limited education and interaction with computers. Furthermore, the study was implemented under field conditions. To conduct the study, an existing HIV risk assessment instrument was adapted for use with the computer. Only slight modifications were made to the content of the instrument. To facilitate data collection with this population, audio enhancement and touch screen were used. Three scales measuring comfort, skill and perceived privacy were developed. Results of analysis showed that drug users are comfortable responding to an HIV risk assessment using computer assisted interviewing. Drug users also perceived that they possessed the requisite skill to successfully complete the interview. And, study participants reported that they believed that their responses using the computer interview would remain private and confidential. Only minor differences in scale scores based on sociodemographic characteristics were found among study participants. Implications of the findings are discussed.

Adult↗
PubMed1998

Mutations in RNA polymerase II and elongation factor SII severely reduce mRNA levels in Saccharomyces cerevisiae.

Elongation factor SII interacts with RNA polymerase II and enables it to transcribe through arrest sites in vitro. The set of genes dependent upon SII function in vivo and the effects on RNA levels of mutations in different components of the elongation machinery are poorly understood. Using yeast lacking SII and bearing a conditional allele of RPB2, the gene encoding the second largest subunit of RNA polymerase II, we describe a genetic interaction between SII and RPB2. An SII gene disruption or the rpb2-10 mutation, which yields an arrest-prone enzyme in vitro, confers sensitivity to 6-azauracil (6AU), a drug that depresses cellular nucleoside triphosphates. Cells with both mutations had reduced levels of total poly(A)+ RNA and specific mRNAs and displayed a synergistic level of drug hypersensitivity. In cells in which the SII gene was inactivated, rpb2-10 became dominant, as if template-associated mutant RNA polymerase II hindered the ability of wild-type polymerase to transcribe. Interestingly, while 6AU depressed RNA levels in both wild-type and mutant cells, wild-type cells reestablished normal RNA levels, whereas double-mutant cells could not. This work shows the importance of an optimally functioning elongation machinery for in vivo RNA synthesis and identifies an initial set of candidate genes with which SII-dependent transcription can be studied.

Cell Division↗
PubMed1992

Role of cAMP-dependent protein kinase in cAMP-mediated vasodilation.

In this study, the role of adenosine 3',5'-cyclic monophosphate (cAMP)-dependent protein kinase A (PKA) in cAMP-dependent relaxation was assessed in the isolated-perfused rat lung using a PKA inhibitor, Rp-cAMPS, 8-bromo-cAMP (8-BrcAMP), and the diterpene activator of adenylate cyclase (AC), forskolin (FSK). A role for K+ channels was also assessed with the nonselective K+ channel blocker, tetraethylammonium (TEA, 10 mM), and an ATP-sensitive K+ channel inhibitor, glibenclamide (GLI, 100 microM). Both 8-BrcAMP (0.1-1.0 mM) and RSK (0.1-10 microM) dose-dependently attenuated the peak pressor response to alveolar hypoxia (HPR). Rp-cAMPS potentiated the HPR and attenuated 8-BrcAMP-mediated vasodilation but had no effect on FSK-mediated vasodilation. FSK-mediated vasodilation was not mimicked by 1,9-dideoxy-FSK, which is biologically inactive on AC but alters K+ channels identically to FSK, nor was it attenuated by the platelet-activating factor antagonist SRI 63-441 or the cyclooxygenase inhibitor indomethacin. TEA, but not GLI, attenuated FSK-mediated vasodilation. Similarly, TEA attenuated 8-BrcAMP-mediated vasodilation. These results support roles for PKA and indirect gating of a non-ATP-sensitive K+ channel in mediating cAMP-dependent pulmonary vasodilation.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1986

IgA deficiency in shar-pei dogs.

Two shar-pei puppies examined because of signs of sinopulmonary disease, one of which also had skin disease, had deficient IgA concentrations. Deficient serum IgA concentrations also were confirmed in 30 of 39 (76.9%) clinically normal adult dogs in two colonies of shar-peis. Both courses of disease--sinopulmonary signs and chronic skin disease and a benign clinical course--have been reported in human patients with IgA deficiency. Thus, the shar-pei might be an appropriate model for studying the immunopathology of IgA deficiency in man.

Animals↗
PubMed1985

The pharmacokinetics and dynamics of oxprenolol: a simulation study with six subjects.

Experimental results of plasma concentration determinations and lowering of exercise heart rate for six subjects taking a conventional tablet and a sustained release preparation of oxprenolol have been analysed by a comprehensive computer simulation model. Individual plasma values were simulated using a lest squares procedure and the results were applied to evaluate individual release patterns following dosage with the sustained release preparation. Application of the model to the lowering of exercise heart rate indicated that the response is in a steady state with the plasma values and that the response-concentration relation is of the saturable, Emax, type. The parameters for this were evaluated for each subject for the results after a dose of a conventional tablet. These parameters were applicable to the results after dosage with a sustained release preparation. The method should be applicable to other sustained release preparations.

Adult↗
PubMed1980

Light scattering studies of the solubilization of some esters of p-aminobenzoic acid by lysophosphatidylcholine.

Light scattering equipment has been constructed using a vertically polarized helium-neon laser and a phase-sensitive detection system. The apparatus has been used to determine the micellar weight of lysophosphatidylcholine (LPC), giving values of 1.33 x 105 in water and 1.47 x 105 in 0.05 M sodium chloride; the sols showed some degree of polydispersity. The light scattering apparatus has also been used to study the solubilization by LPC of three n-alkyl esters of paraminobenzoic acid. These compounds caused a considerable increase in the scattered light, particularly at higher LPC concentrations.

4-Aminobenzoic Acid↗