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Biomedical subjects

A Muñoz

Publications and source records attributed to A Muñoz.

At least 343 records · Page 19Linked to original sources
PubMed1994

Lectin typing of beta-haemolytic streptococci of groups A and B.

Patterns of agglutination of 124 clinical isolates of beta-haemolytic streptococci (30 group A and 94 group B isolates) by 21 commercial lectins are reported. Cell suspensions were untreated. Nine (30%) of the group A isolates, and 23 (24%) of the group B isolates, were agglutinated by at least one of the lectins. Ten different patterns of agglutination were observed with group A and 15 with group B streptococci. No pattern, except that of non-agglutination by any lectin, was common to group A and group B isolates. In view of the growing interest in the use of lectin typing there is a need for standardisation of assay procedures to enable meaningful comparison of the results of different research groups.

Agglutination Tests↗
PubMed1994

Drug-related behavior change for HIV transmission among American injection drug users.

While high risk drug-related behaviors for human immunodeficiency virus (HIV) transmission among injection drug users (IDUs) are asserted to have declined over time in response to the AIDS epidemic, evidence from longitudinal cohorts has been sparse. In a cohort of 810 IDUs (442 seronegatives and 368 seropositives) in Baltimore, we identified drug-related risk behaviors at four consecutive semi-annual visits. Using robust methods for repeated measurements and multiple logistic regression, we estimated the probabilities of maintaining and reducing risk behaviors according to HIV serostatus and time in the study. Seropositive participants were more likely to maintain lower risk behaviors, and behavior maintenance increased with time in study for both seronegative and seropositive IDUs. Greater risk reduction (towards non-use and not sharing injection equipment) was seen among seropositive IDUs, with behavior change occurring soon after enrollment in the study. While behavior changes have been reported, many active IDUs, especially those still at risk for acquiring HIV infection, have not adequately reduced their risk. Continuing prevention programs and efforts in vaccine development are imperative to reduce the risk of HIV infection among IDUs.

Baltimore↗
PubMed1994

Drug smoking, Pneumocystis carinii pneumonia, and immunosuppression increase risk of bacterial pneumonia in human immunodeficiency virus-seropositive injection drug users.

To examine the risk factors for the first episode of bacterial pneumonia among human immunodeficiency virus (HIV)-seropositive injection drug users (IDUs), medical record review was performed on IDUs participating in a cohort study from January 1988 to June 30, 1992. HIV-seropositive IDUs with a first episode of bacterial pneumonia (n = 40) were matched with up to five HIV-seropositive control subjects without bacterial pneumonia (n = 197) by date of entry (+/- 3 mo) and length of follow-up. Odds ratios (OR) were estimated using conditional logistic regression. The incidence of bacterial pneumonia was 1.93 in 100 person-years in HIV seropositive and 0.45 in 100 person-years in HIV seronegative subjects (relative incidence = 4.3; 95% CI 2.4 to 7.5). In univariate analyses, CD4 lymphocyte count < 200 cells/microliters previous episode of Pneumocystis carinii pneumonia (PCP), age between 30 and 40 yr and smoking illicit drugs (marijuana, cocaine, or crack) were associated with bacterial pneumonia. Cigarette smoking was associated with an increased odds of bacterial pneumonia (OR = 2.0), but this was not statistically significant because it was nearly universal in this cohort. In multivariate analysis, CD4 < 200 cells/microliters (OR = 6.75, 95% CI 2.13 to 21.42) and smoking illicit drugs (OR = 2.24, 95% CI 1.03 to 4.89) remained significantly associated with bacterial pneumonia. The odds ratio for cigarette smoking in the final model remained at 2.08 but was still not significant (95% CI 0.49 to 8.70). Smoking illicit drugs had the strongest effect on risk of bacterial pneumonia among HIV-seropositive IDUs with a previous history of PCP (OR = 22.94; 95% CI 2.18 to 241.10).

AIDS-Related Opportunistic Infections↗
PubMed1994

Temporal trends in the incidence of HIV-1-related neurologic diseases: Multicenter AIDS Cohort Study, 1985-1992.

OBJECTIVE: To describe temporal trends in the incidence of human immunodeficiency virus (HIV)-related neurologic diseases in the Multicenter AIDS Cohort Study from 1985 to 1992. METHODS: The incidence rates of six neurologic disorders were examined: toxoplasmosis, cryptococcal meningitis, primary CNS lymphoma, progressive multifocal leukoencephalopathy, HIV dementia, and sensory neuropathy. Poisson modeling was used to test linear trends over time and the effects of progressive immunosuppression, antimicrobial prophylaxis, and antiretroviral drug therapy. RESULTS: There was an upward temporal trend in all incidence rates, except for HIV dementia. Progressive immunosuppression in the cohort explained all calendar trends except for sensory neuropathy, where an increasing temporal trend remained even after adjusting for CD4+ cell count, and for HIV dementia where a slight decline was noted, although the effects were not statistically significant. We noted a protective trend of antimicrobial prophylaxis on toxoplasmosis and cryptococcal meningitis, but, in contrast, use of antiretroviral agents was not protective against HIV dementia. Men receiving didanosine, zalcitabine, or stavudine were more likely to develop sensory neuropathy. CONCLUSION: Despite the earlier and more widespread use of antimicrobial and antiretroviral agents, neurologic conditions still occurred frequently in this cohort, with annual rates above 1.5 per 100 person-years for HIV dementia and sensory neuropathy. Sensory neuropathy seems to be increasing in incidence and HIV dementia declining slightly in this cohort. As the epidemic matures and more people with profound immunosuppression live longer, the overall incidence of HIV-related neurologic diseases can be expected to rise.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Antibodies to hepatitis C virus in human immunoglobulins: clinical meaning and diagnostic difficulties in children undergoing bone marrow transplant.

Anti-HCV antibodies were detected in 11 children undergoing BMT. All of them had received intravenous immunoglobulins (Ig) at a dose of 500 mg/kg every 2 weeks for the first 100 days post-BMT. Antibody titers appeared after the first dose and became undetectable between 1 and 6 months after the last dose of Ig. Detection of anti-HCV antibodies in these multitransfused patients raised doubts about their clinical significance. The clearance of antibody titers in the ensuing months, negativity of HCV RNA in the serum of the patients and the presence of anti-HCV in some batches of the commercial preparations administered supported the diagnosis of a passive transfer of antibodies and that true HCV infection could be ruled out. Routine screening of donors with the most sensitive tests and exclusion of anti-HCV positive sera from plasma pools should be mandatory. The presence of anti-HCV in these products has important clinical implications, leading to more expensive and time-consuming diagnostic procedures.

Bone Marrow Transplantation↗
PubMed1994

The dorsal column-medial lemniscal projection of anuran amphibians.

The efferent connections of the dorsal column nucleus (DCN) of the anuran amphibians Rana ridibunda and Xenopus laevis have been studied by means of bidirectionally transported tracers. Efferent projections from the DCN innervate the spinal cord, tegmentum of the brain stem, cerebellum, torus semicircularis and thalamus. The pattern of connectivity of the anuran DCN is largely comparable to that of amniotic vertebrates although some peculiarities are found.

Animals↗
PubMed1994

[Evaluation of coronary revascularization: comparison between perfusion with dipyridamole Tc99m sestaMIBI and amrinone-echocardiography as predictors of viability].

We studied left ventricular perfusion and motility in 37 patients with coronary artery disease and disturbances of parietal motility, aged 57 +/- 9 years old, before and after revascularization. Perfusion was assessed with dipyridamole-tc99m MIBI SPECT and motility was assessed with two dimensional echocardiography with amrinone. Myocardial segments were defined as normal, viable or necrotic in both studies. Eighteen subjects were subjected to angioplasty and 19 to coronary bypass surgery. Submitted SPECT and echocardiography were repeated 64 +/- 15 and 69 +/- 23 days after revascularization respectively. The concordance between SPECT and echocardiographic pre-revascularization diagnosis was 60.1% Eighty one percent of segments considered viable with SPECT and 71% thus considered with echocardiography improved after revascularization. Likewise, 50% of segments considered necrotic with SPECT and 68% of segment thus considered with echocardiography did not improve. It is concluded that although there is a good concordance between both methods, they have limitations on the study of myocardial viability and should be considered as second choice.

Adult↗
PubMed1994

On the basal ganglia of amphibians: dopaminergic mesostriatal projections.

Recent studies have revealed a rather dense dopaminergic innervation of basal forebrain areas in anurans and urodeles. The aim of the present study is not only to extend these observations to the third order of amphibians, i.e. the Gymnophiona, but also to determine the cells of origin of the dopaminergic projection to the basal forebrain by means of combined tract-tracing/transmitter-immunohistochemical techniques. Immunohistochemistry with antibodies against tyrosine hydroxylase (TH) and dopamine (DA) demonstrated some remarkable differences in the distribution of DA fibers within the basal forebrain. Whereas in anurans the nucleus accumbens receives a major DA input, in urodeles the DA input to the striatum prevails. In gymnophionans, both basal forebrain structures receive an equally dense DA innervation. The double-labeling studies revealed also differences in the distribution of the cells of origin of the DA striatal input. Although in anurans and urodeles DA cells in both the posterior tubercle and the midbrain tegmentum contribute to this projection, the mesostriatal projection of urodeles is more elaborated than that of anurans.

Amphibians↗
PubMed1994

Primary afferents and second order projections of the trigeminal system in a frog (Rana ridibunda).

The trigeminal primary afferents and the projections from the sensory trigeminal nuclei were studied in a frog (Rana ridibunda) by means of tract-tracing techniques. Primary fibers from separate ophthalmic, maxillary and mandibular trigeminal branches form short ascending and long descending tracts. Ascending fibers innervate the principal trigeminal nucleus, a field just dorsal to the trigeminal motor nucleus, and the supratrigeminal nucleus. Descending fibers terminate separately in the descending trigeminal nucleus, depending on their branch of origin. Other primary targets are the rhombencephalic reticular nuclei, the ventral and caudal octaval nuclei, the nucleus of the solitary tract and the spinal cord. Ipsilateral intranuclear connections are accompanied by extratrigeminal projections that reach, among others, the thalamus, the mesencephalic tectum and the cerebellum. It is concluded that many amniotic features are shared by the anuran trigeminal system.

Afferent Pathways↗
PubMed1994

Cardiovascular toxicities related to the infusion of cryopreserved grafts: results of a controlled study.

To evaluate cardiovascular toxicities associated with the infusion of cryopreserved grafts, we prospectively monitored the infusions of 29 autologous bone marrow transplant (BMT) recipients. Fifteen allogeneic BMT recipients served as a control group. Cardiac rhythm was recorded continuously with the Holter technique from at least 2 h before the start of graft infusion until 24 h after completion. Blood pressure was closely monitored during the same period. Graft infusions were performed through a standard transfusion filter with breaks between aliquots. When the infusion had commenced, diuretics were given frequently (40 and 40% of allogeneic BMT and autologous BMT recipients, respectively) to avoid fluid overload. Non-cardiovascular clinical toxicities were observed more frequently in autologous BMT patients (41% vs 6%, p = 0.02) and no significant differences were seen between autograft and allograft recipients in any of the measured cardiovascular parameters. The heart rate decreased slightly in both groups but no patient in either group had a heart rate of < 60 b.p.m. or heart block. No significant changes in blood pressure were detected in either group. Ventricular ectopic beats/atrial ectopic beats ratio increased in the autologous BMT group after graft infusion (0.7 vs 0, p = 0.1). Time to engraftment did not differ significantly from other published series. Our results suggest that increasing infusion time of cryopreserved material and using a standard filter may reduce toxicities associated with the infusion of cryopreserved grafts. Early administration of diuretics may contribute to better control of blood pressure.

Adolescent↗
PubMed1994

c-erbA and v-erbA modulate growth and gene expression of a mouse glial precursor cell line.

The c-erbA alpha protooncogene coding for the thyroid hormone (T3) receptor (TR alpha 1) and the viral, mutated v-erbA oncogene were expressed in an immortal mouse glial cell line (B3.1) using retroviral vectors. c-erbA alpha expression led to a decrease in cell proliferation in high and low serum conditions, both in the presence and in the absence of T3. In serum-free medium, c-erbA-expressing cells (B3.1 + TR alpha 1) were completely arrested, whereas cells expressing v-erbA (B3.1 + v-erbA) showed a higher DNA synthesis rate than normal B3.1 cells. Although proliferation of all three cell types was stimulated by platelet-derived growth factor and basic fibroblast growth factor, differences were also observed in the response to these agents. B3.1 + TR alpha 1 cells were more sensitive to platelet-derived growth factor than B3.1 and B3.1 + v-erbA cells. In contrast, B3.1 cells responded to basic fibroblast growth factor better than B3.1 + TR alpha 1 or B3.1 + v-erbA cells. Insulin-like growth factor I potentiated the action of platelet-derived growth factor and basic fibroblast growth factor. Again, different responses to treatment with insulin-like growth factor I alone were observed; B3.1 + TR alpha 1 cells did not respond to it, whereas B3.1 + v-erbA cells showed a dramatic stimulation by this agent. Interestingly, in the presence of T3, the blockade in B3.1 + TR alpha 1 cell proliferation was accompanied by the down-regulation of the typical astrocytic genes, glial fibrillary acidic protein and vimentin. These hormone effects were not found in v-erbA-expressing cells. In addition, v-erbA inhibited the basal expression of the cyclic nucleotide phosphodiesterase gene, an oligodendrocytic marker.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

An X-protocol based medical teleconsultation system using low or high speed networks. A specific-design approach.

The objective of this proposal is to provide solutions for the necessities of teleconsultation or telediagnosis among medical professionals, using work stations within the X-Windows environment and applicable in communication lines with an extensive range of bandwidths and operating system independence. Among the advantages sought are savings in transportation, improvement in the quality of the medical attention provided and continued training for the medical professional.

Computer Communication Networks↗
PubMed1994

Thrush and fever as measures of immunocompetence in HIV-1-infected men.

The occurrence of Pneumocystis carinii pneumonia (PCP) in human immunodeficiency virus type 1 (HIV-1)-infected individuals with high CD4+ counts indicates poor immunologic function. Thrush and persistent fever, easily recognized clinically, are potential measures of immunocompetence. This analysis establishes the complex interactions of CD4+ count, thrush, and persistent fever to predict the occurrence of PCP. Analyses used 20,632 person visits from 2,568 HIV-1-seropositive homosexual or bisexual men participating in the Multicenter AIDS Cohort Study (MACS). Comprehensive examinations were conducted semiannually, while occurrences of PCP were assessed continuously. The occurrence of thrush and fever increase in frequency as CD4+ levels decrease. The relative hazard of PCP in the presence of thrush compared with the absence of thrush rises (p < 0.05) from 1 for the lowest CD4+ category to approximately 5 in the highest categories. The relative hazard of PCP in the presence of fever compared with the absence of fever is above one (p < 0.05) in all CD4+ categories. No cases of PCP occurred in individuals on PCP prophylaxis with CD4+ counts > 200/mm3. These results suggest that HIV-1-related symptoms provide a measure of failing immune function that is not reflected by enumeration of CD4+ lymphocytes alone and support the United States Public Health Service recommendation that symptomatic individuals with CD4+ counts > 200/mm3 should be considered for PCP prophylaxis.

Bisexuality↗
PubMed1994

Changes in employment, insurance, and income in relation to HIV status and disease progression. The Multicenter AIDS Cohort Study.

While patterns of health care financing for HIV have received considerable attention in the literature, the financial impact of disease on individuals living with HIV infection has been underexplored, particularly in relation to disease progression. Therefore, we sought to document changes in employment, income, and insurance coverage over time among HIV-negative, HIV-positive, and AIDS-diagnosed gay and bisexual men participating in the Multicenter AIDS Cohort Study (MACS) and to document measures of financial hardship. Persons with AIDS (PWAs) were 2.7 times more likely to lose full-time employment over a 6-month period than seronegative persons (p < 0.05), and loss of employment was strongly associated (p < 0.001) with both loss of private health insurance and loss of income. Twenty-seven percent of PWAs reported having financial difficulty meeting their basic expenses, compared with 10% of seronegative (p < 0.001), and 15% of PWAs, compared with only 9% of seronegative persons, said that, for financial reasons, they had not sought medical care that they thought they needed (p = 0.028). When 27% of PWAs in a cohort such as this report financial difficulty meeting their basic expenses, it is clear that the response of our public health and social welfare systems has not been adequate. Given that the problems experienced by most persons infected by HIV are considerably more severe than those experienced by MACS participants, the imperative for action is even greater.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Retinoic acid posttranscriptionally up-regulates proteolipid protein gene expression in C6 glioma cells.

The proteolipid protein (PLP) gene codes for the major central nervous system myelin protein. We have studied the effects of different agents on the expression of the PLP gene in C6 glioma cells. Retinoic acid (RA), but not dexamethasone, estradiol, insulin, growth hormone, or vitamin D3, had a drastic effect, increasing 10-20-fold the level of PLP mRNA. Concomitantly, RA also induced the appearance of the corresponding immunoreactive protein. The increase in PLP RNA level showed a slow kinetics and was blocked by cycloheximide, suggesting a posttranscriptional regulation by RA. Nuclear run-on assays confirmed that the rate of PLP gene transcription was unchanged by RA. In contrast, we found that retinoic acid augmented PLP mRNA stability, causing a substantial increase in its half-life. RA action was independent of cell density, serum, or PDGF but was partially inhibited by bFGF. On the other hand, thyroid hormone caused a moderate increase in PLP mRNA levels in C6 cells but only when the low numbers of thyroid receptors in these cells were increased by retrovirally mediated expression of an exogenous c-erbA/TR alpha-1 gene. Our results indicate that RA specifically up-regulates PLP expression in glioma C6 cells at a posttranscriptional level by increasing PLP RNA half-life.

Animals↗