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Biomedical subjects

L Pollack

Publications and source records attributed to L Pollack.

At least 37 records · Page 2Linked to original sources
PubMed1993

Stress, control, coping, and depressive mood in human immunodeficiency virus-positive and -negative gay men in San Francisco.

This study examined the relationship between stress, appraised control, and coping and depressive mood in 425 human immunodeficiency virus-positive and -negative gay men in San Francisco. Depressive mood was assessed by self-report in 1988 and 1989. Participants were also surveyed in 1989 on the stress in their lives, their appraised control over the stress, and the ways they coped. Depressive mood in 1988 and symptoms of human immunodeficiency virus disease in 1989 accounted for 50% of the variance in 1989 depressive mood; stress, appraised control, and coping accounted for an additional 10% of the variance in depressive mood in 1989. Path analysis indicated: stress appraised as controllable was associated with involvement coping, which in turn was associated with diminished depressive mood; stress associated with detachment was associated with increased depressive mood; and stress was also directly associated with increased depressive mood.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Stress, coping, and high-risk sexual behavior.

We examined the relation between stress, coping, and a high-risk sexual behavior (unprotected anal intercourse) in 398 nonmonogamous gay and bisexual men from the AIDS Behavioral Research Project in San Francisco. Unprotected anal intercourse during the previous month, the amount of stress experienced during the previous month in each of 10 domains, six types of coping (self-controlling coping, escape-avoidance, distancing, planful problem-solving, seeking social support, and positive reappraisal), and spiritual beliefs and spiritual activities were assessed through self-report. There was no relation between stress and unprotected anal intercourse. However, there was a relation between coping and unprotected anal intercourse. Subjects who reported unprotected anal intercourse used sex more of the time to help cope with stressful situations than did subjects who did not report unprotected anal intercourse. Unprotected anal intercourse was negatively associated with seeking social support and spiritual activities and positively associated with self-controlling coping, which involves keeping one's feelings to oneself, and positive reappraisal. The findings suggest that social aspects of coping may be a key to understanding differences between those who engage in high-risk sexual behavior and those who do not.

Adaptation, Psychological↗
PubMed1991

A case of glutaric acidemia type II (severe multiple acyl-CoA dehydrogenation disorder) with subsequent prenatal exclusion in a sibling.

A case of severe multiple acyl-CoA dehydrogenation disorder is described. This is the second such case reported to have had an elevated maternal serum alpha-fetoprotein and normal amniotic alpha-fetoprotein. The child's 3-day extrauterine life was characterized by intractable acidosis, respiratory distress, and ventricular fibrillation. The characteristic biochemical, morphologic, and microscopic findings of this condition are reviewed. A subsequent pregnancy was evaluated using chorionic villus sampling and analysis of cultured trophoblasts. The trophoblasts were biochemically normal, and a normal child was subsequently delivered. Since the manifestations of this disorder developed in utero, prenatal diagnosis and therapy offer the only hope for a more prolonged survival.

Acidosis↗
PubMed1990

Appraisal of four pre-column derivatization methods for the high-performance liquid chromatographic determination of free amino acids in biological materials.

Reversed-phase high-performance liquid chromatography (RP-HPLC) is a powerful method for assaying physiological amino acid concentrations in biological fluids. Four pre-column derivatization methods, with o-phthaldialdehyde (OPA), 9-fluorenylmethyl chloroformate (FMOC-Cl), phenyl isothiocyanate (PITC) and 1-dimethylaminonaphthalene-5-sulphonyl chloride (dansyl-Cl), were assessed with respect to their applicability in biological research. The methods permit the measurement of 21-26 major amino acids in 13-40 min. The superior sensitivity favours the use of OPA, FMOC-Cl and dansyl-Cl techniques. Because of instability of the OPA adducts, automated on-line derivatization is required when using this method in general practice. Application of the PITC method, although less sensitive, is useful in clinical chemistry, where sample availability is rarely a problem. Cystine determination is not feasible when using OPA or FMOC-Cl and with PITC the reproducibility and linearity are poor, whereas the dansyl-Cl method allows reliable quantitation. The four methods are currently used to perform ca. 8000 OPA and 5000-6000 FMOC-Cl, PITC and dansyl-Cl analyses of biological samples per year. The results obtained with the RP-HPLC methods compare favourably with those derived from conventional ion-exchange amino acid analyses. When the guard column is regularly changed after 120 analyses, the separation remains satisfactory for at least 700 OPA, 800 FMOC-Cl, 150 PITC and 500 dansyl-Cl analyses. Careful control of factors and limitations inherent in the various methodologies is a prerequesite for proper identification and appropriate quantitation.

Amino Acids↗
PubMed1990

Help-seeking behaviors of people with sexual problems.

Help-seeking activities associated with the sexual problems of community respondents (N = 503) were studied. Major findings include (i) a majority of respondents reported some form of social help-seeking from predominantly informal rather than professional helpers; (ii) a significant increase over early adulthood in the likelihood of reporting a dyadic sexual problem was evidenced, however there was no parallel change in help-seeking behaviors with age; (iii) help-seeking from intimates was associated with obtaining help from other informal contacts; (iv) help-seeking from extrafamilial, but not familial, supports was found to covary with income, and (v) a "normative" sequence to help-seeking behaviors was identified. Also discussed is the present work's relevance to research on human immunodeficiency virus transmission.

Adult↗
PubMed1990

Longitudinal predictors of reductions in unprotected anal intercourse among gay men in San Francisco: the AIDS Behavioral Research Project.

Predictors of unprotected anal intercourse were examined among 508 gay men in San Francisco. The cohort was recruited in 1983-84 at which time 49.8 percent of non-monogamous men (N = 435) and 71.2 percent of monogamous men (N = 73) reported practicing unprotected anal intercourse. Only 12 percent of non-monogamous and 27.4 percent of monogamous men reported these practices in 1988. The non-monogamous men who practiced unprotected anal intercourse in 1984 were more likely to be younger, to report that unprotected anal intercourse was their favorite sexual activity, to be low in perceived efficacy to change sexual behavior, to report that friends were more likely to engage in high-risk behaviors, to have less knowledge of health guidelines, and to be less depressed at that time. Non-monogamous individuals who in 1984 reported that unprotected anal intercourse was their favorite sexual activity were more likely to practice that behavior in 1988. Those who knew their serostatus as positive were less likely to report unprotected anal intercourse in 1988. These data infer that in order to modify AIDS-related high-risk behaviors, community risk-reduction programs be differentially aimed at young persons so as to increase personal efficacy about risk reduction, challenge peer norms, promote antibody testing, and eroticize safer sexual activities.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Relapse from safer sex: the next challenge for AIDS prevention efforts.

Prevention campaigns to reduce sexual transmission of human immunodeficiency virus (HIV) typically emphasize the initial adoption of safer sex techniques. We present data from a 5-year prospective study to show that the vast majority of resident gay men in San Francisco have made these initial risk reductions. Rather, relapse from safer sex techniques is now the predominant predominant kind of high-risk sex, accounting for approximately two thirds of all prevalent high-risk sex in the 1988 wave of data collection. Predictors of relapse from safer sex are identified, and these are discussed in terms of their implications for preventing relapse from the exclusive practice of safe sex. In communities that have already manifested widespread behavioral risk reductions and in which HIV infection is highly prevalent, finding ways to prevent relapse of behavioral risk reductions will be the next important challenge in the fight against acquired immune deficiency syndrome.

Acquired Immunodeficiency Syndrome↗
PubMed1989

[A cystine-containing short-chain peptide as a potential cystine source for parenteral nutrition].

For the first time, in vivo utilization of two highly soluble and stable cystine containing synthetic short chain peptides, N,N'-bis-L-alanyl-L,L-cystine and N,N'-bis-glycyl-L,L-cystine, was investigated in adult rats. Within 5 min after an intravenous bolus, blood samples were drawn (inferior vena cava) and plasma amino acid and peptide levels were determined using RP-HPLC (precolumn derivatization with 1-dimethylaminonaphthalene-5-sulfonylchloride). Both peptides were rapidly cleared from plasma (estimated elimination time: 4 min for the glycyl peptide and less than 2 min for the alanyl peptide). The initial high amounts of N-L-alanyl-L,L-cystine and N-glycyl-L,L-cystine as well as the prompt increase of the constituent free amino acids alanine, glycine and cystine strongly suggest that the peptide disappearance is mainly due to a very fast two-step hydrolysis in the extracellular compartment, presumably catalyzed by soluble and/or plasma membrane bound peptidases. The observed rapid hydrolysis may serve as first evidence that short chain peptides with C-terminal cystine residue may represent efficient sources of free cystine in parenteral nutrition.

Alanine↗
PubMed1989

Older Americans and AIDS: transmission risks and primary prevention research needs.

The growing number of AIDS cases among older Americans (50 years and older) is of increasing concern. In the context of primary prevention, findings are reviewed that bear on the modes of HIV transmission (blood transfusion, sexual) among older individuals and knowledge of the magnitude of the AIDS problem represented by these routes of infection. Lastly, a proposed research agenda is focused on questions of primary prevention of HIV transmission.

Acquired Immunodeficiency Syndrome↗
PubMed1988

In vivo utilization of cystine-containing synthetic short-chain peptides after intravenous bolus injection in the rat.

For the first time, in vivo utilization of two highly soluble and stable cystine-containing synthetic short-chain peptides, bis-L-alanyl-L-cystine and bis-glycyl-L-cystine, were investigated in adult rats. Within 5 min after an intravenous bolus, blood samples were drawn (inferior vena cava) and plasma amino acid and peptide levels were determined using RP-HPLC (precolumn derivatization with 5-dimethylaminonaphthalene-1-sulfonylchloride). Both peptides were rapidly cleared from plasma (estimated elimination t1/2: 4 min for the glycyl peptide and less than 2 min for the alanyl peptide). The initial high amounts of mono-L-alanyl-L-cystine and mono-glycyl-L-cystine as well as the prompt increase of the constituent free amino acids alanine, glycine and cystine strongly suggest that the peptide disappearance is mainly due to a very fast two-step hydrolysis in the extracellular compartment, presumably catalyzed by soluble and/or plasma membrane-bound peptidases. The observed rapid hydrolysis may serve as first evidence that short-chain peptides with C-terminal cystine residue may represent efficient sources of free cystine in parenteral nutrition.

Alanine↗
PubMed1984

Relationship between health beliefs and psychological variables in diabetic patients.

The present paper is focused on the relationship between psychological variables and health beliefs in 93 diabetic men. A Diabetes Health Belief Scale was used to assess general health motivation, treatment beneficial, severity, susceptibility, psychological barriers, cues to action, and structural elements. The psychological variables included two measures of locus of control, depression, somatization, interpersonal sensitivity, obsessive-compulsiveness, anxiety, self-esteem, and attitudes toward diabetes, doctor, and medical care. Ten of the 11 psychological variables were correlated with various aspects of health beliefs. This indicates the extent to which the health beliefs are enmeshed with the psychological dynamics of the person. It would seem important to take such a psychological profile into consideration when attempting to understand and even alter the health beliefs.

Attitude to Health↗
PubMed1983

Correlation of glycosylation forms with position in amino acid sequence.

We surveyed published reports on about 50 glycoproteins whose amino acid sequence, glycosylation sites, and type of glycosylation at a particular site have been established. We note that high-mannose substances were rarely found at the N-terminal side of a previously glycosylated complex site. There was a very definite distribution of complex sites about the N-terminal region. Furthermore, secreted glycoproteins usually contained only complex oligosaccharides whereas membrane proteins contained both types. We suggest that the position of the glycosylation site with respect to the N-terminus affects the extent of oligosaccharide processing and subsequent presentation of complex or high-mannose structures in the mature glycoprotein. This review relates glycosylation type to its position in the known sequence of given proteins and discusses these observations in light of known glycosylation processing reactions.

Amino Acid Sequence↗