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Biomedical subjects

C Hoff

Publications and source records attributed to C Hoff.

At least 55 records · Page 3Linked to original sources
PubMed1993

Disclosing HIV seropositivity to significant others.

OBJECTIVES: To examine gay men's patterns of self-disclosure of HIV seropositivity to friends, lovers, relatives and colleagues; to assess the effects of disclosure; and to identify reasons for not disclosing to particular individuals. DESIGN: Longitudinal questionnaire survey of gay men. METHODS: A total of 163 HIV-positive men participating in the AIDS Behavioral Research Project, a longitudinal study of San Francisco gay men, completed questionnaires about their self-disclosure patterns, health status, and psychological well-being. RESULTS: HIV-positive men were most likely to disclose their status to lovers and closest gay friends. Asymptomatic men were less likely to disclose to relatives and colleagues than symptomatic men. Friends and lovers were rated as responding more helpfully than relatives and colleagues. Men who perceived their significant others as responding more helpfully were less depressed and anxious currently and 1 year later. A variety of reasons were given for not disclosing, including not wanting to worry others, fear of discrimination, fear of disrupting relationships, and emotional self-protection. CONCLUSION: While disclosure can have advantages for both HIV-positive individuals and their significant others, HIV-positive individuals must be assured that the benefits of doing so will outweigh the potential costs.

Adult↗
PubMed1993

Association between maternal-fetal HLA-DR relationships and fetal growth.

PROBLEM: To determine whether maternal-fetal human leukocyte antigen (HLA) antigenic relationships are associated with differential fetal growth in weight. METHOD: A cohort of 659 primigravid women were enrolled in this study in the prepartum period and their neonates were subsequently examined. Anthropometric, maternal cigarette smoking behavior, health, pregnancy, and delivery data were collected; serogenetic typing was conducted on maternal and cord bloods to determine maternal and neonatal HLA antigenic phenotypes. Women and their neonates were assigned to one of the four different types of maternal-fetal relationships existing at each of the HLA-A, B, DR, and DQ loci. Birthweights were treated quantitatively and qualitatively (neonates classified as growth-retarded or normal). RESULTS: After controlling for other factors influencing birthweight (e.g., smoking, maternal body size), significantly lower birthweight trends (P < .01) were found when neonates expressed a single HLA-DR antigen and their mothers expressed a second HLA-DR antigen that was foreign (allogeneic) to their neonate. CONCLUSION: Our findings supports the hypothesis that lack of maternal immune exposure to fetal HLA antigens is associated with a slowing of fetal growth. However, in this situation slowed fetal growth is most likely to occur when the fetus is potentially exposed to maternal HLA-DR alloantigens. We believe this sheds new light on immunologic events at the maternal-fetal interface influencing fetal growth. We present one possible explanation to account for this finding.

Birth Weight↗
PubMed1992

Immunophenotypic characterization of owl monkey peripheral blood mononuclear cells.

A two-phase study was initiated to delineate the peripheral blood lymphocyte populations present in owl monkeys and to correlate those populations with immune response and parasitism during malaria infection. The goal of phase I of the study was to elucidate a monoclonal antibody panel that could be used to characterize peripheral blood mononuclear cell (PBMC) populations with flow cytometric techniques. Forty-two monoclonal antibodies (reported to be reactive with human and macaque lymphocyte antigens) were screened for activity to owl monkey PBMC. Eleven monoclonals were found to react: anti-H42A (MHC Class II DP-like); anti-TH14B (MHC Class II DR-like); and anti-TH81A5 (MHC Class II DQ-like); anti-H58A (MHC Class I); anti-DH59B (granulocyte and monocyte); anti-B1 (B cell); anti-T4 (CD4); anti-Leu3a (CD4); anti-Leu11a (CD16); anti-60.3 (CD18); and anti-OKM1 (NK and monocyte). In a preliminary retrospective study correlating antibody titers, parasitemia values, and MHC Class I and Class II marker profiles on PBMC to test antigens used in malaria vaccine trials, a significant negative association was observed between cells bearing MHC Class II molecules and the other elements of the comparison. In summary, an appropriate panel of monoclonal antibodies has been identified for characterizing PBMC in owl monkeys, and preliminary studies indicate a possible association between clinical outcome and expressed phenotypic PBMC markers.

Animals↗
PubMed1992

Maternal-fetal HLA-DR relationships and pregnancy-induced hypertension.

OBJECTIVE: Some studies have found an increased prevalence of pregnancy-induced hypertension among women sharing HLA antigens with their spouses or fetuses, thus supporting the hypothesis that maternal sensitization to fetal HLA alloantigens reduces the risk for pregnancy-induced hypertension. However, not all studies have confirmed these findings. No investigators have examined the four different types of maternal-fetal HLA relationships in their studies of pregnancy-induced hypertension. Our goal was to examine such associations to test further the HLA-allosensitization hypothesis. METHODS: We conducted a cohort study of pregnancy-induced hypertension among 683 nulliparous women. Women and their neonates were typed for HLA-A, -B, -DR, and -DQ antigens using serologic techniques to establish maternal-fetal relationships. RESULTS: We found an increased prevalence of pregnancy-induced hypertension when the fetus, but not the mother, was potentially exposed to HLA-DR alloantigens (maternal allogenicity) compared with the other three conditions combined (P < .003). Controlling for confounding factors, the increased prevalence of pregnancy-induced hypertension persisted in situations of maternal HLA-DR allogenicity (P < .007). CONCLUSIONS: Based upon our observations and other immunologic studies of pregnancy-induced hypertensive and uncomplicated pregnancies, we conclude that a maternal humoral response against fetal anti-HLA-DR immunoglobulin (IgG) antibody may influence the development of pregnancy-induced hypertension. This could occur when an immunocompetent fetus is exposed to maternal HLA-DR alloantigens, maternal exposure to fetal HLA-DR alloantigens alloantigens, maternal exposure to fetal HLA-DR alloantigens is not possible, and fetal IgG antibody bears paternally inherited markers allogeneic to the mother.

Eclampsia↗
PubMed1992

In vitro lymphocyte activity in women with endometriosis--an altered immune response?

OBJECTIVE: To determine the possible role of the immune system in the pathogenesis of endometriosis. DESIGN: The lymphocyte proliferative response in the presence of autologous endometrial cells was assayed by tritiated thymidine incorporation. SETTING: Patients were recruited from a university outpatient clinic. MAIN OUTCOME MEASURE: To determine the lymphocyte proliferative response to endometrium in controls and patients with endometriosis. PARTICIPANTS: Twenty patients with endometriosis and 26 control women were studied. RESULTS: The lymphocyte proliferative response in the presence of autologous endometrium was significantly lower in women with endometriosis when compared with controls. CONCLUSION: This study indicates that an altered lymphocyte/endometrial cell relationship is operational in women with endometriosis and may contribute to the pathogenesis of the disease.

Adult↗
PubMed1991

Signs of cellular immunosuppression correlate with HLA-DR phenotypes in healthy HIV-negative homosexuals: preliminary findings.

Twelve healthy, anal-receptive, homosexual Caucasian males who were seronegative for HIV antibody were typed for HLA-DR antigens. Flow cytometry was used to immunophenotype peripheral blood lymphocytes bearing the CD4, CD8, LEU7, and combined CD8 and LEU7 antigens. These individuals had reported a large number of sexual partners within a five-year period preceding this study. Each individual was assigned a score based on the Hardy-Weinberg frequency of their HLA-DR phenotype in the Caucasian population. The larger the value of this score, the more common the HLA-DR phenotype, the smaller the score, the rarer the phenotype in the population at large. A significant inverse correlation was observed between this score and the proportion of lymphocytes with CD8 and LEU7 antigens. Lymphocytes bearing these two antigens have in vitro suppressor activity and are elevated in patients with human immunodeficiency virus (HIV) infection. The inverse association between CD8+/LEU7+ cells and frequency of HLA-DR phenotypes is consistent with the hypothesis that individuals with rarer phenotypes whose partners are drawn from the population at large are more likely to be challenged during anal insemination, which results in immunosuppression (alloantigenic challenge hypothesis). On the other hand, it is possible that an association exists between certain HLA-DR phenotypes and immune status. Although these observations were made in a very small sample, we believe that the strength of this association provides justification for further investigation into the possibility that alloantigenic challenge may increase the risk for infection, if exposed to HIV, and augment the immunosuppressive action of HIV once significant infection has occurred.

Antigens, Differentiation↗
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↗
PubMed1989

Does exposure to HLA alloantigens trigger immunoregulatory mechanisms operative in both pregnancy and AIDS?

The complex biological processes responsible for regulating the immune system are presently the subject of considerable interest and study. New insight into this process comes from a variety of observations and it is the purpose of this communication to develop the hypothesis that two seemingly quite disparate observations point to a common biological mechanism bearing on immunoregulation. The observations concern the unique immunologic relationship between mother and fetus and the immunoregulatory abnormalities encountered in HIV-induced acquired immunodeficiency syndrome (AIDS). Exposure to foreign (allo) major histocompatibility complex (MHC) antigens can potentially occur during pregnancy, the transfusion of blood or blood products, or anal insemination. The hypothesis, in its simplest form, states that such MHC alloantigenic exposure triggers a sequence of immunoregulatory mechanisms resulting in immunosuppression and that this response has evolved in placental mammals as a means of protecting the fetus from maternal immune rejection and promoting optimal fetal development.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Lack of correlation of maternal human immunodeficiency virus infection with neonatal malformations.

A malformation syndrome has been proposed in infants with acquired immunodeficiency syndrome or acquired immunodeficiency syndrome-related complex secondary to congenital infection with human immunodeficiency virus (HIV) in the United States and Europe. To determine whether embryopathy is detectable in HIV-exposed African infants, 85 infants of HIV-seropositive mothers and 98 infants of HIV-seronegative mothers in Nairobi, Kenya, were examined for minor and major anomalous features shortly after birth. No mother used intravenous drugs. With the exception of growth failure no anomalous feature was associated with in utero HIV exposure. No increase in the number of anomalous features per infant was correlated with HIV, nor did any infant have the reported malformation syndrome. Thus in this population of African infants examination for anomalous features during the neonatal period failed to identify those infants with fetal exposure to HIV.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Maternal smoking: greater effect on males, fetal tobacco syndrome?

We tested the recently proposed criteria for a Fetal Tobacco Syndrome (FTS) on a sample of 925 primiparous black women (including 204 smokers) and their neonates. The proposed FTS criteria included proportional growth retardation (ponderal index greater than 2.26, birth weight less than 2,500 g) in term neonates. Only 19 neonates (2%) in our study fulfilled the FTS morphometric criteria, and of these only 8 had smoking mothers. Nonetheless, the negative effect of maternal smoking on fetal growth (birth weight and length) as reported from earlier investigations was clearly evident in our own data (P less than .01). Separate analysis by fetal sex revealed that the negative effect of maternal smoking upon fetal growth is more pronounced among males than females. We concluded that fetal sex should be taken into account in studies of maternal smoking effects. As for evidence for the existence of the FTS, it remains to be proven.

Adolescent↗
PubMed1986

Maternal-fetal ABO/Rh antigenic relationships and human fetal development.

Six hundred ninety-nine primigravid mothers and their neonates were grouped into three distinct classes on the basis of maternal-fetal antigenic relationships for the ABO and Rh blood groups. Maternal-fetal units were classified as maternal dominant if the mother possessed more antigens than the neonate, equivalent if both possessed the same number of antigens, and fetal dominant if the neonate possessed more antigens than the mother. After confounding variables were controlled, a significant increase in adjusted mean birth weight was observed from maternal-fetal equivalence to fetal dominance and there was a significant increase in adjusted crown-heel length from maternal dominance to fetal dominance. No trends were observed for adjusted head circumference. However, when the sample was stratified on the basis of sex of the neonate, a highly significant increase in adjusted mean head circumference was observed for female infants from maternal dominance through fetal dominance. These observations suggest maternal-fetal ABO/Rh relationships are associated with differential fetal growth trends.

ABO Blood-Group System↗
PubMed1986

Diet, blood pressure, and hematologic variables of nulliparous women attending a prenatal clinic.

Diet, hematology, and blood pressures of 1800 black and white nulliparous women were surveyed at a prenatal clinic. Although black women had higher blood pressure and lower hemoglobin and hematocrit means that white women, no racial differences were found for prevalence of anemia or hypertension. White women reported less adequate intakes of protein/iron and vitamins B and C compared with black women. No associations between dietary intake and anemia or hypertension were found in univariate analysis. Failure to find racial differences in prevalence of hypertension and anemia may reflect improvements in the dietary supplementation and health care available to lower socioeconomic, black women in the last decade.

Adolescent↗