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Biomedical subjects

J Pindyck

Publications and source records attributed to J Pindyck.

At least 19 recordsLinked to original sources
PubMed1995

A randomized trial of an education and support program for HIV-infected individuals.

OBJECTIVES: To assess the effectiveness of an intervention for providing information and support to HIV-positive donors on changes in their sexual behavior, and to assess which donor characteristics are predictive of behavior change. DESIGN: Subjects were randomly assigned to a structured intervention or community referral group. Follow-up assessments were conducted every 6 months. SETTING: New York City, New York, USA. PARTICIPANTS: A cohort of 271 HIV-infected persons who donated blood to the New York Blood Center. INTERVENTION: Donors randomized to the structured intervention program met individually with a nurse for counseling and were offered a six-session support group. The program was designed to provide information, encourage safer sexual behavior and provide support. MAIN OUTCOME MEASURES: Sexual behavior, psychological distress and psychological help seeking, and immune function. RESULTS: In both groups there was a large decrease over time in reports of unsafe sexual activity. However, more than 30% of participants in both groups reported unsafe sexual activity at the 1-year follow-up visit. Donors randomized to the structured intervention program did not report significantly more behavior change at the 1-year follow-up. CONCLUSIONS: Better programs to promote behavior change in seropositive individuals are needed.

Adult↗
PubMed1993

Depressive symptoms in blood donors notified of HIV infection.

OBJECTIVES: Understanding more about the psychological state of persons notified of human immunodeficiency virus (HIV) infection is critical for designing notification and counseling programs that will have the most positive effect. METHODS: The subjects were blood donors who had been notified of HIV infection by the New York Blood Center. A nurse elicited a medical history, performed a limited medical examination, and asked the subjects to complete a questionnaire that included questions about drug use, sexual behavior, and psychological characteristics. The subjects completed another questionnaire approximately 2 weeks later. RESULTS: The average depressive symptom scores for both men and women were substantially higher than scores typically found in representative population samples. More than a quarter of the men and more than a third of the women reported seeking psychological or psychiatric services in the first few weeks following notification. CONCLUSIONS: Anticipating and meeting individuals' psychological needs may be necessary if HIV screening programs are to address effectively the needs of persons infected with HIV.

Adaptation, Psychological↗
PubMed1991

Behavior changes after notification of HIV infection.

BACKGROUND: To learn more about how people who did not volunteer for testing react to information about HIV infection, we assessed short-term behavior changes in HIV-positive blood donors. METHODS: Blood donors who were notified at the New York Blood Center that they were HIV positive were asked to participate in a study. A nurse elicited a medical history, performed a limited medical examination, and asked participants to complete a questionnaire that included questions about drug use, sexual behavior, and psychological characteristics. Participants were asked to return in 2 weeks to complete another questionnaire. RESULTS: Many fewer men and women reported engaging in unsafe sexual behaviors in the 2 weeks preceding the follow-up visit than had reported such behaviors prior to notification. These changes were greater than those other investigators have reported, but about 40% of the participants still reported unsafe sexual activity at the follow-up interview. CONCLUSIONS: To make nonvolunteer screening programs for HIV infection more effective in reducing the spread of HIV infection, we need to learn more about how to help people change their high-risk behaviors.

Adolescent↗
PubMed1991

Trends in sociodemographic and behavioral characteristics of HIV antibody-positive blood donors.

This paper describes the sociodemographic characteristics of people who donated blood to the New York Blood Center between April 1985 and February 1988 and tested positive for antibodies to HIV. Information on HIV-related risk factors and knowledge of blood screening is presented for seropositive donors who participated in an evaluation study. The most commonly reported risk factor among men was sexual contact with another man, and many of the male seropositive donors reported sex with an intravenous (IV) drug user or use of IV drugs. The proportion of men reporting sexual contact with another man decreased over the period of the study, and the proportion reporting use of IV drugs or sex with an IV drug user increased. Awareness of blood screening for HIV antibodies increased over the study period. The greatest increase was among those donating for transfusion, but only about a quarter of seropositive donors used the confidential unit exclusion (CUE) process.

Adolescent↗
PubMed1990

Epidemiology of hepatitis C virus. A preliminary study in volunteer blood donors.

In a survey carried out from 1985 through 1986, volunteer blood donors to The Greater New York Blood Program were tested for two surrogate markers for non-A, non-B hepatitis--elevation of alanine aminotransferase level and presence of antibody to hepatitis B core antigen. Stored serum samples from selected donors were also recently tested for antibody to hepatitis C virus (anti-HCV). Anti-HCV was detected in 0.9% to 1.4% of donors and was higher in black and Hispanic donors than in white donors. Anti-HCV prevalence increased with increasing age through the fourth decade of life, but decreased thereafter, possibly reflecting the disappearance of detectable antibody with time. Anti-HCV correlated with both alanine aminotransferase level and the presence or absence of antibody to hepatitis B core antigen. These associations suggest that donor screening for elevation of alanine aminotransferase level and presence of antibody to hepatitis B core antigen was, as expected, at least partially effective in preventing transfusion-associated non-A, non-B hepatitis. The detection of anti-HCV in donors who have neither an elevation of alanine aminotransferase level nor presence of antibody to hepatitis B core antigen suggests that donor screening for anti-HCV will further reduce the risk of transfusion-associated hepatitis.

Adult↗
PubMed1988

Sociodemographic and behavioral characteristics of HIV antibody-positive blood donors.

This paper describes the sociodemographic and behavioral characteristics of 173 blood donors who were confirmed by Western blot tests to have antibodies to human immunodeficiency virus (HIV), the etiologic agent for acquired immunodeficiency syndrome (AIDS). Seropositive donors were predominantly young, unmarried, and male, and major risk factors could be identified for almost all donors. However, more than 20 per cent of the study participants were women, and many participants were not aware that they were at risk of infection. The heterogeneity of the study population, the lack of awareness among many subjects of risk factors and self-exclusion procedures, and the high level of distress among many subjects after notification, emphasize the need for intensive, well-designed education and support programs.

Adult↗
PubMed1987

Blood donation by the elderly. Clinical and policy considerations.

At present, healthy potential blood donors older than the age of 66 years often leave the donor pool for reasons of age alone, despite the fact that this demographic group is growing, is a potentially willing source of blood products, and constitutes the cohort with highest per capita use of blood and its derivatives. There is no clinical or physiological rationale for this. We performed a controlled study to measure the feasibility and safety of blood donation by healthy elderly donors aged 66 years and older, compared with a younger cohort aged 55 to 65 years of age. A study group of prior donors aged 66 years and older and a control group of prior donors between the ages of 50 and 65 were sent letters inviting them to donate blood. The volume donated did not differ between the two groups. In the older group, there were eight immediate reactions, seven mild and one moderate. The control population experienced seven immediate reactions, six mild and one severe. We conclude that it is both clinically feasible and efficient to recruit healthy prior donors older than the age of 66 years for blood donation. As a group, this population is potentially able to donate large volumes of blood and do so without any difference in immediate or short-term reactions. Further study of hemodynamic variables as more objective markers of safety is needed.

Adult↗
PubMed1986

Health education about AIDS among seropositive blood donors.

The New York Blood Center is developing a health education and psychosocial support program for blood donors who are notified that they are HIV antibody positive. The goals of that program are: to provide accurate and intelligible information about the test results to notified donors; to encourage behavior that will reduce the likelihood of spreading the virus; to encourage notified donors to behave in ways that will reduce the probability that they will develop AIDS; and to provide support and facilitate functional coping responses. This article reviews the theoretical and empirical work which informs the intervention program, and it describes how the program is being implemented.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Hormonal regulation of fibrinogen synthesis in cultured hepatocytes.

Most of what was originally known of the effects of hormones on fibrinogen synthesis was based, as noted above, on experiments involving surgical removal of endocrine glands. Some caution should be exercised when using such in vivo experiments to derive the hormonal requirements of fibrinogen synthesis, however, since multiple hormonal alterations often occur in these animals. The development of a variety of ex vivo systems has allowed investigators to more carefully control the hepatocellular environment. The work of several laboratories, including our own, has now made it clear that hormones and other agents directly stimulate hepatocellular synthesis of fibrinogen. From the studies summarized here, using chick embryo hepatocytes as a model, several generalizations emerge: Fibrinogen synthesis may be considered to be a "constitutive" liver function, since hepatocytes cultured without serum, hormones or other macromolecular supplements synthesize this protein at a basal rate for several days. Addition of certain hormones (e.g. T3, dexamethasone, insulin), individually and in physiological concentrations, elicits an increase in fibrinogen production, varying with each agent in onset, dose, minimum exposure required and accompanying effects on the synthesis of other plasma proteins. Glucocorticoids and thyroid hormones are similar in the selectivity of their stimulation (neither affects albumin or transferrin synthesis) but differ in that thyroid hormones need to be present for just a short "triggering" period. The stimulation of fibrinogen synthesis by insulin occurs only following prolonged exposure to concentrations 10-times higher than the very low doses to which albumin synthesis responds rapidly.

Adrenocorticotropic Hormone↗
PubMed1983

Structural analysis of fibrinogen synthesized by cultured chicken hepatocytes in the presence or absence of dexamethasone.

Hepatocyte monolayers, derived from chick embryos and cultured in chemically defined medium without hormones, synthesize and secrete fibrinogen that resembles chicken plasma fibrinogen immunochemically and structurally. Addition of a synthetic glucocorticoid, dexamethasone, to the cultured cells resulted in an appreciable and relatively selective increase in fibrinogen synthesis. Autoradiography of fibrinogen that had been metabolically labelled with [35S]methionine and then subjected to SDS-polyacrylamide gel electrophoresis, unreduced or under disulfide-reducing conditions, revealed that only dimeric forms of fibrinogen, containing undegraded A alpha, B beta, and gamma chains, were secreted under stimulated and unstimulated culture conditions.

Animals↗
PubMed1982

Transfusion of granulocyte rich buffy coats to neutropenic patients.

Granulocyte rich buffy coats were transfused to infected neutropenic patients when leukapheresis donors were not available. Efficacy of transfusions was evaluated from data supplied by hospitals administering them. Buffy coats separated from ACD blood contained a mean of 4.9 X 10(8) granulocytes. Fifty-seven patients received a course consisting of a mean of 3.8 transfusions. Of these, 27 received a mean of 17.5 units per transfusion and had a survival rate of 44.4%, which was not significantly different from the 50.0% found in 30 who received a mean of 11.1 units per transfusion. No significant difference in survival rate was found between 31 patients with acute leukemia and 26 with other disorders or 38 patients with positive and 19 with negative cultures. Finally, no significant difference in survival rate was noted between patients who received a course of greater than or equal to four transfusions or less than or equal to three transfusions in any of the above groups. Survival rates were less than those generally reported following similar courses of leukapheresis units. Buffy coat transfusions consisting of a mean of approximately 17.5 units as produced during this study have therefore been shown to be not generally beneficial. The increased survival seen in some studies utilizing leukapheresis products may relate in part to the larger number of granulocytes they contained. Greater benefit from buffy coat transfusions might result if the number of granulocytes infused were increased. Evaluation of possible efficacy associated with transfusions of increased numbers of buffy coat units further enriched with granulocytes may be justified when leukapheresis donors are not available.

Adult↗
PubMed1981

Serum stimulation of plasma protein synthesis in culture is selective and rapidly reversible.

Primary hepatocyte monolayers, derived from chick embryos, can be cultured from the onset in a completely chemically defined medium, free of added hormones. The liver cells synthesize and secrete a wide spectrum of plasma proteins for several days in this serum-free environment. Addition of fetal bovine serum elicits a 3-5-fold increase in the production of certain plasma proteins: fibrinogen, albumin, and the alpha1-globulin M. This effect of serum is selective; transferrin and plasminogen syntheses are enhanced less than 1.5-fold. Significant stimulation is observed with 0.1% fetal bovine serum, and half-maximal values for individual plasma proteins are obtained with concentrations ranging between 0.4 and 1%. The stimulatory activity of serum shows no developmental or species specificity. Plasma is active as serum derived from the same blood sample. The hepatocytes respond rapidly to serum, significant changes in albumin synthesis occurring less than 1 h after serum addition or removal. The effect of short exposure is fully reversible. These results establish the capacity of low concentrations of serum to stimulate plasma protein synthesis and underscore the importance of studying the effects of hormones and other factors under serum-free conditions. The findings suggest that, in addition to the classical hormones, ubiquitous but as yet uncharacterized serum components play a role in controlling this major hepatic function.

Animals↗
PubMed1981

Thyroid hormone stimulation of plasma protein synthesis in cultured hepatocytes.

The direct effect of thyroid hormones on hepatocellular plasma protein synthesis has been studied in primary monolayer cultures derived from chick embryo liver. The chemically defined medium used for plating and maintaining the cultures contained no other hormones, protein, or serum supplement. Addition of physiological concentrations (10 nM) of triiodothyronine or thyroxine produced 3-fold or greater increases in the rates of synthesis of fibrinogen and three other major secreted proteins. By comparison albumin, transferrin, and total protein synthesis were not substantially increased. The enhanced synthesis of selected plasma proteins could be detected 6 h after initial addition of triiodothyronine. Exposure of the cells to the hormone for only 30 min was nearly as effective as continuous exposure in eliciting the ultimate response. Triiodothyronine exerted its half-maximal effect at a concentration of 1 nM. Diminished potency was associated with less iodination of the hormone; a marked reduction was noted with di-iodinated thyronine and no stimulatory activity at all with either mono- or non-iodinated thyronine.

Animals↗