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Biomedical subjects

A Muñoz

Publications and source records attributed to A Muñoz.

At least 433 records · Page 24Linked to original sources
PubMed1990

Seasonal and annual variation of antibody to HIV-1 among male inmates entering Maryland prisons: update.

Previous serosurveys of antibody to HIV-1 among incoming male inmates in Maryland between April and June of 1985, 1986 and 1987 have shown a prevalence of 7.0, 7.7 and 7.0%, respectively, with stability persisting after multivariate adjustment. To investigate seasonality and update annual trends, excess sera were obtained from incoming male inmates between August 1987 and August 1988. Correctional personnel also provided demographic variables of age, race, offense, category, and jurisdiction. Once rendered anonymous, specimens were assayed for antibody to HIV-1 using enzyme-linked immunosorbent assay and Western blot. For the 12-month study period, 415 (7.9%) of 5262 consecutive male entrants were seropositive. On univariate and multivariate analyses, no significant change in seroprevalence or risk by subgroup was noted by month or season. For data from April to June 1988, 113 (8.1%) of 1398 consecutive entrants demonstrated anti-HIV-1; seropositivity was associated with age greater than 25 years, Black race, and Baltimore jurisdiction. No significant change was found over time in seroprevalence or risk of HIV-1 infection by subgroup in multivariate analysis combining data for 1985-1988. These data provide additional evidence to suggest stability of HIV-1 seroprevalence in Maryland male prison entrants.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Two quick estimates of the HIV prevalence in homosexual men in Los Angeles, New York and San Francisco. The Multicenter AIDS Cohort Study.

Two rough methods are given to estimate the combined HIV prevalence in Los Angeles, New York and San Francisco in homosexual men. Both methods are related to the back calculation technique, and use AIDS surveillance data and information obtained from the Multicenter AIDS Cohort Study. Both methods suggest that the combined HIV prevalence is approximately 100,000, with a possible range of 80,000-140,000.

Cohort Studies↗
PubMed1990

Ectopic expression of the erythrocyte band 3 anion exchange protein, using a new avian retrovirus vector.

A retrovirus vector was constructed from the genome of avian erythroblastosis virus ES4. The v-erbA sequences of avian erythroblastosis virus were replaced by those coding for neomycin phosphotransferase, creating a gag-neo fusion protein which provides G418 resistance as a selectable marker. The v-erbB sequences following the splice acceptor were replaced by a cloning linker allowing insertion of foreign genes. The vector has been tested in conjunction with several helper viruses for the transmission of G418 resistance, titer, stability, transcription, and the transduction and expression of foreign genes in both chicken embryo fibroblasts and the QT6 quail cell line. The results show that the vector is capable of producing high titers of Neor virus from stably integrated proviruses. These proviruses express a balanced ratio of genome length to spliced transcripts which are efficiently translated into protein. Using the Escherichia coli beta-galactosidase gene cloned into the vector as a test construct, expression of enzyme activity could be detected in 90 to 95% of transfected target cells and in 80 to 85% of subsequently infected cells. In addition, a cDNA encoding the avian erythrocyte band 3 anion exchange protein has been expressed from the vector in both chicken embryo fibroblasts and QT6 cells and appears to function as an active, plasma membrane-based anion transporter. The ectopic expression of band 3 protein provides a visual marker for vector function in these cells.

Alpharetrovirus↗
PubMed1990

The chicken c-erbA alpha-product induces expression of thyroid hormone-responsive genes in 3,5,3'-triiodothyronine receptor-deficient rat hepatoma cells.

To determine the capacity of the chicken c-erbA (cTR-alpha) gene product in regulating expression of known thyroid hormone-responsive genes, both the cTR-alpha and the viral v-erbA genes were expressed in FAO cells, a rat hepatoma cell line defective for functional thyroid hormone receptors. Upon nuclear expression of the cTR-alpha protein the cells become responsive to thyroid hormone, as detected by expression of a number of genes (malic enzyme, phosphoenolpyruvate carboxykinase, and Na+/K(+)-ATPase) reported to be indirectly induced by the hormone in vivo. In addition, our data show that the c-erbA product directly activates the Moloney murine leukemia virus promoter in a ligand-dependent manner. The data show that the chicken c-erbA-alpha protein can modulate the expression of rat genes under either direct or indirect control by thyroid hormone.

Animals↗
PubMed1990

HIV-1 infection: no evidence of cognitive decline during the asymptomatic stages. The Multicenter AIDS Cohort Study.

Cross-sectional studies have not adequately resolved the question of whether subjects infected with HIV-1 may suffer cognitive decline during the early, asymptomatic stages of the infection. We studied longitudinally 238 asymptomatic healthy HIV-1-infected homosexual/bisexual men (CDC groups 2 and 3) and 170 uninfected controls in the Multicenter AIDS Cohort Study with neuropsychological testing at semiannual intervals. A comparison of change in scores between visits 1 and 4 as well as a multivariate autoregressive analysis revealed no evidence of decline in test performance over time in the HIV-1-infected group compared with the seronegative controls. These findings suggest that a gradual cognitive decline does not occur during the early, asymptomatic stages of HIV infection.

Adult↗
PubMed1990

Predictors of the initiation of psychotherapeutic medicine use.

This study examined the hypothesized predictive association between illicit drug use and the onset of prescribed psychotherapeutic medicine use. The effect of psychiatric symptoms on this relationship was also explored. Data were gathered retrospectively, through standardized household interviews conducted in 1981 for the Baltimore site of the National Institute of Mental Health Epidemiologic Catchment Area Program. For this analysis, the sample was restricted to 1,716 respondents ages 18-44 at the time of interview, drawn by probability sampling area household residents of all adult ages. Using Cox proportional hazards models, the onset of psychotherapeutic medicine use was modeled as a function of illicit drug use and psychiatric symptoms, both defined as time-dependent covariates. Newly observed in this analysis was an independent association of illicit drug use with psychotherapeutic medicine use, which was unexplained by psychiatric symptoms (relative hazard = 2.61, 95% confidence interval (CI) = 2.15, 3.18). Adjustment for age of onset of alcohol intoxication did not alter the impression that illicit drug users were more likely to initiate use of prescribed psychotherapeutic medicines (relative hazard = 2.52, 95% CI = 2.02, 3.11).

Adult↗
PubMed1990

Requirement for the C-terminal domain of the v-erbA oncogene protein for biological function and transcriptional repression.

In contrast to the normal thyroid hormone receptor, the v-erbA product fails to bind hormone due to mutations in the C-terminal ligand binding domain and thus appears to represent a hormone-independent, oncogenic transcription factor. Therefore, we asked whether or not the C-terminal domain of v-erbA is required for its biological activity and putative transcriptional control functions by analysing mutants with altered C-termini. A v-erbA protein truncated in the C-terminal domain lacked detectable biological activity in transformed erythroblasts and its transcriptional repression function with respect to the band 3 gene was abolished. The protein displayed a nuclear location and could still bind to DNA, indicating that the N-terminal region retained DNA-binding activity but was insufficient to produce characteristic v-erbA changes in erythroblasts. Another biologically defective v-erbA variant with a small frameshift towards the extreme C-terminus also failed to repress band 3, indicating a requirement for a specific C-terminal structure in repression. However, this mutant retained partial biological activity, stimulating erythroblasts to grow at a higher rate than cells containing a completely inactive, deleted v-erbA gene. The results demonstrate that the mutated hormone-binding domain, in addition to the DNA-binding region, is critical for v-erbA biological and transcriptional control functions.

Amino Acid Sequence↗
PubMed1990

[Transesophageal Doppler echocardiography in the evaluation of cardiac pathology].

Transesophageal echocardiography is one of the most important innovations that have lately turned up for the evaluation of the cardiac patient. This technical approach consists not only of the study of the two dimensional image but of the cardiac flows obtained with pulsed and color Doppler as well, using a gastroscopic probe to which an ultrasonic transducer has been adapted. In this paper we make a revision of the methodology used in our laboratory. We discuss the utility of this technical approach not only for the study of the ambulatory patient but also for the critically ill patient.

Ambulatory Care↗
PubMed1990

HIV-1, sexual practices, and contact with foreigners in homosexual men in Colombia, South America.

From October 1985 to November 1987, a sample of 294 Colombian homosexual men volunteered to answer a questionnaire on sexual practices and consented to HIV-1 testing. Testing for HIV-1 was performed using an ELISA and those positive were confirmed with envelope- and core-specific ELISAs. Statistical methods for data analysis included Mantel-Haenszel methods on contingency tables. The overall seropositivity rate was 21.1%. Subjects who reported a receptive role (either as predominantly receptive or as mixed receptive-insertive intercourse) had a seropositivity rate of 23.7%, which was significantly higher than the 10.3% found in those reporting predominantly insertive intercourse (RR = 2.30, 95% C.I. = 1.16-4.57). For subjects reporting receptive intercourse, sexual contact with foreign visitors was a significant risk factor for HIV-1 infection (RR = 1.84, 95% C.I. = 1.13-3.00). Factors of borderline significance included having had more than ten homosexual partners in the preceding year (RR = 1.53) and a history of international travel (RR = 1.43). These associations did not hold for those reporting predominantly insertive intercourse. The data indicate the need to monitor the spread of HIV-1 at the international level and provide information on subgroups of high transmission rates.

Adult↗
PubMed1990

Incidence of Kaposi's sarcoma in a cohort of homosexual men infected with the human immunodeficiency virus type 1. The Multicenter AIDS Cohort Study Group.

Longitudinal data on 2,125 participants in the Multicenter AIDS Cohort Study (MACS) with documented antibodies to the human immunodeficiency virus type 1 (HIV-1) were used to examine the incidence of acquired immune deficiency syndrome (AIDS)-related Kaposi's sarcoma (KS) over time and to determine if sexual practices and hematologic variables prior to diagnosis differed for participants who develop KS vs. non-KS AIDS (NKS). In the first 4 years of the study, 84 seropositive men were observed to develop KS and 307 presented with an AIDS diagnosis other than KS. A systematic trend in the incidence of KS over time was not apparent in this population. The number of anal-receptive intercourse partners prior to diagnosis declined in a similar fashion for both AIDS groups. Although the number of partners with whom the men performed rimming decreased prior to diagnosis for both AIDS groups, a greater proportion of the KS AIDS group had performed this activity with multiple partners than had the non-KS AIDS group. Furthermore, history of oral gonorrhea was significantly (p = 0.027) more prevalent in the KS group. In addition, the KS AIDS group had lower cytomegalovirus antibody levels prior to diagnosis and higher levels of total immunoglobulin G. The groups did not differ with respect to baseline hematological measures, temporal trends in helper and suppressor T cells, or hepatitis B surface antigen or antibody. Given this profile of factors associated with the occurrence of KS, an infectious agent, in addition to HIV-1, is plausible as a proposed cofactor in the development of KS.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Repression of transcription mediated at a thyroid hormone response element by the v-erb-A oncogene product.

Several recent observations, such as the identification of the cellular homologue of the v-erb-A oncogene as a thyroid-hormone receptor, have strongly implicated nuclear oncogenes in transcriptional control mechanisms. The v-erb-A oncogene blocks the differentiation of erythroid cells, and changes the growth requirements of fibroblasts and erythroblasts. Mutations in v-erb-A protein have led to the loss of its affinity for thyroid hormones but do not affect its DNA-binding ability, a property required for biological activity. We report here the identification of a novel thyroid-hormone response element (TRE) in the long terminal repeat of Moloney murine leukaemia virus that binds the c-erb-A-alpha protein. The v-erb-A protein abolishes the responsiveness of this TRE to thyroid hormone, although it has a lower affinity than the normal receptor for the TRE. The data indicate that overexpressed v-erb-A protein negatively interferes with normal transcriptional-control mechanisms, and that amino-acid substitutions have altered its DNA-binding properties.

Base Sequence↗
PubMed1989

Four-day continuous infusion of cisplatin and 5-fluorouracil in head and neck cancer.

A combination of cisplatin and 5-fluorouracil, both administered 4 days continuously as infusion, was assessed in advanced head and neck cancer. Of the 37 patients studied, there were 15 complete and 17 partial responses (40.5% and 45.9%, respectively). Survival is 79.1% at 22 months. None of the patients in complete response has relapsed. In general toxic effects were moderate. Given as initial treatment, the regimen is effective and of considerable use in this type of patient.

Adult↗
PubMed1989

Transmission of retroviruses by transfusion of screened blood in patients undergoing cardiac surgery.

We determined the rates of seroconversion to human immunodeficiency virus type 1 (HIV-1) and human T-cell leukemia virus Type I (HTLV-I) in a cohort of patients receiving transfusions of blood components screened for antibody to HIV-1. Preoperative and postoperative serum samples were collected from 4163 adults undergoing cardiac surgery who received 36,282 transfusions of blood components. The postoperative samples from all patients were tested for serologic evidence of HIV-1 infection, and those that were positive were compared with the corresponding preoperative samples. One case of HIV-1 transmission by transfusion of screened blood components was identified; two preexisting HIV-1 infections were found. Samples from 2749 patients were tested similarly for serologic evidence of HTLV-I infection; these patients received 20,963 units of blood components. Five new cases and two preexisting cases of HTLV-I infection were detected. The observed risk of HIV-1 transmission by transfusion was 0.003 percent per unit; the risk of HTLV-I transmission was 0.024 percent per unit. We conclude that there is a very small risk of HTLV-I infection from transfused blood products that have been screened for antibodies to HIV-1, but that it is nearly 10-fold higher than the risk of HIV-1 infection.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Development of antibodies to HIV-1 is associated with an increase in circulating CD3+CD4-CD8- lymphocytes.

This study investigated whether seroconversion with respect to human immunodeficiency virus, type 1 (HIV-1) was associated with an increase in lymphocytes expressing the CD3+CD4-CD8- phenotype. Proportions and absolute numbers of CD3+, CD4+, and CD8+ lymphocytes were determined prospectively over a 2.5-year period on 4954 homosexual and/or bisexual men participating in the Multicenter AIDS Cohort Study. Of the 4808 men whose serostatus at entry could be verified, 1745 were seropositive (SP) for antibodies to HIV-1 at entry into study, 2795 were uniformly seronegative (SN) for HIV-1 for 30 months, and 268 were seroconverters (SC) with respect to HIV-1 during this period. For each of six semiannual evaluations, proportions and numbers of CD3+CD4-CD8- lymphocytes (calculated as CD3- (CD4 + CD8] were both significantly greater in the SP group than in the SN group (P less than 0.001). Mean CD3+CD4-CD8- levels in the SC group were indistinguishable from those in the SN group before seroconversion, but by 3-9 months after seroconversion the SC group demonstrated absolute numbers of CD3+CD4-CD8- lymphocytes which were significantly increased (P less than 0.001) compared to the SN group using linear regression methods with adjustment for correlation of measurements within an individual over time. An additional significant increase occurred by 21-27 months after seroconversion (P = 0.006). These results are consistent with an association of HIV-1 seroconversion with an increase in circulating T lymphocytes expressing the CD3+CD4-CD8- phenotype (double negative T cells), a decrease in CD3-CD4-CD8+ natural killer cells, or both. An increase in double negative T cells could reflect a host defense mechanism against HIV-1 or effects of HIV-1 on T cell development.

Antigens, Differentiation, T-Lymphocyte↗