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Biomedical subjects

A Muñoz

Publications and source records attributed to A Muñoz.

At least 109 records · Page 6Linked to original sources
PubMed2001

[Addisonian crisis as first manifestation of adrenal gland insufficiency in patient diagnosed with lung cancer].

Adrenal insufficiency or Addison's disease is actually a rare illness associated with numerous pathologies. We describe the case of a fifty years old male with lung adenocarcinoma and metastasis in both adrenal glands, who was receiving chemotherapy with mytomicin, ifosfamide and cisplatin (MIC), and was diagnosed of adrenal insufficiency as a result of acute episode addisonian crisis. Many times, the clinic symptoms of adrenal insufficiency can go unnoticed due to its low specifity and to mixing up with other syndromes. Hypoadrenalism has been described in association with many tumours, specially with non-Hodgkin's lymphoma. It seems that there is a discordance between the number of patients with bilateral metastatic adrenal destruction and the documented cases of clinic insufficiency. Once the adrenal failure is suspected, the diagnosis and hormone replacement treatment are really easy. Addison's disease ethiologies are revised putting special emphasis on those related with cancer patients.

Addison Disease↗
PubMed2000

Structure-reactivity relationships among metallothionein three-metal domains: role of non-cysteine amino acid residues in lobster metallothionein and human metallothionein-3.

Metallothionein (MT) domains of different origins, exhibiting distinct, highly conserved cysteine positions, show differences in metal-cysteine coordination and reactivity. Lobster MT, which includes two Cd3S9 beta domains, was chosen as a basic model to study the structure-function relationship among the clusters. The possible influence of (1) the position of the cysteine residues and (2) the steric and electrostatic effects of neighboring amino acids on the folding and stability of MT clusters have been examined with the native lobster beta C and beta N domains, each having nine cysteines and binding three M2+ ions, and a modified domain beta C-->N, in which the cysteines of the C-terminal domain are relocated so they are spaced as in the N-terminal domain. Each has been synthesized and characterized by UV, CD, 113Cd NMR, and 1H NMR spectroscopies. The synthetic native domains (Cd3 beta C and Cd3 beta N) displayed spectroscopic properties, metal-binding affinities, and kinetic reactivity similar to those of the holo protein. In contrast, the modified Cd3 beta C-->N domain was unusually reactive and, in the presence of Chelex, a metal-ion chelating resin, was converted to a Cd5(beta C-->N)2 dimer. These differences in structure and reactivity demonstrate that the requirements for formation of a stable type-B, Cd3S9, beta cluster are more stringent than simply the sequential positions of the cysteines along the peptide chain and include specific interactions with neighboring amino acids. Molecular mechanics calculations suggest that changes of even a single amino acid in lobster Cd3 beta N toward lobster Cd3 beta C-->N or in mammalian MT1 or MT2 toward Cd3 beta-MT3 (GIF) can destabilize their structures.

Amino Acid Sequence↗
PubMed2000

Selection by indication of potent antiretroviral therapy use in a large cohort of women infected with human immunodeficiency virus.

To characterize selection factors related to therapy initiation, the authors investigated the extent to which key markers of human immunodeficiency virus (HIV) disease severity were associated with initiation of potent antiretroviral therapy (ART). Logistic regression was used to determine the effects of CD4+ cell count and HIV RNA level on potent ART initiation during 6-month periods among 2,059 HIV-infected US women enrolled in the Women's Interagency HIV Study. Low CD4+ counts and high HIV RNA levels were significantly (p < 0.05) associated with initiation of potent ART. During all periods between April 1996 and March 1998, CD4+ counts were more strongly associated with potent ART initiation than HIV RNA levels were; however, during the last period, both were associated (odds ratio per 100 CD4+-count decrease = 1.17, p < 0.01; odds ratio per 1 log10 increase in HIV RNA level = 1.48, p < 0.05). For a CD4+ count of 500 cells/ml and an HIV RNA level of 5,000 copies/ml, the probability of potent ART initiation increased from 0.5% to 16.8% between October 1995-March 1996 and October 1997-March 1998, suggesting earlier initiation of potent ART. Given the documented occurrence of confounding by indication, prospectively collected, time-dependent data on markers of disease progression and therapy use should be considered when making population-level comparisons before and after introduction of potent ART.

Adult↗
PubMed2000

Life-supporting human complement regulator decay accelerating factor transgenic pig liver xenograft maintains the metabolic function and coagulation in the nonhuman primate for up to 8 days.

BACKGROUND: It is not known whether the pig liver is capable of functioning efficiently when transplanted into a primate, neither is there experience in transplanting a liver from a transgenic pigs expressing the human complement regulator human complement regulator decay accelerating factor (h-DAF) into a baboon. The objective of this study was to determine whether the porcine liver would support the metabolic functions of non-human primates and to establish the effect of hDAF expression in the prevention of hyperacute rejection of porcine livers transplanted into primates. METHODS: Five orthotopic liver xenotransplants from pig to baboon were carried out: three from unmodified pigs and two using livers from h-DAF transgenic pigs. FINDINGS: The three control animals transplanted with livers from unmodified pigs survived for less than 12 hr. Baboons transplanted with livers from h-DAF transgenic pigs survived for 4 and 8 days. Hyperacute rejection was not detected in the baboons transplanted with hDAF transgenic pig livers; however, it was demonstrated in the three transplants from unmodified pigs. Baboons transplanted with livers from h-DAF transgenic pigs were extubated at postoperative day 1 and were awake and able to eat and drink. In the recipients of hDAF transgenic pig livers the clotting parameters reached nearly normal levels at day 2 after transplantation and remained normal up to the end of the experiments. In these hDAF liver recipients, porcine fibrinogen was first detected in the baboon plasma 2 hr postreperfusion, and was present up to the end of the experiments. One animal was euthanized at day 8 after development of sepsis and coagulopathy, the other animal arrested at day 4, after an episode of vomiting and aspiration. The postmortem examination of the hDAF transgenic liver xenografts did not demonstrate rejection. INTERPRETATION: The livers from h-DAF transgenic pigs did not undergo hyperacute rejection after orthotopic xenotransplantation in baboons. When HAR is abrogated, the porcine liver maintains sufficient coagulation and protein levels in the baboon up to 8 days after OLT.

Acute Disease↗
PubMed2000

High survival rate in infant acute leukemia treated with early high-dose chemotherapy and stem-cell support. Groupo Español de Trasplante de Médula Osea en Niños.

PURPOSE: Infants with acute leukemia have a poor prognosis when treated with conventional chemotherapy. It is still unknown if stem-cell transplantation (SCT) can improve the outcome of these patients. In the present study, we review our experience with SCT in infant acute leukemia to clarify this issue. PATIENTS AND METHODS: We report the results of 26 infants who were submitted to a SCT for acute leukemia. There were 15 cases of acute myeloid leukemia and 10 cases of acute lymphoid leukemia. One patient had a bilineal leukemia. Twenty-two patients were in their first complete response (CR1), three were in their second CR, and one was in relapse. Eight patients were submitted to allogeneic SCT, and 18 underwent autologous SCT. RESULTS: With a median follow-up of 67 months, the 5-year overall survival and disease-free survival (DFS) are 64% (SE = 9%) and 63% (SE = 10%), respectively. Autologous and allogeneic SCT offered similar outcome. There was not any transplant-related mortality, and all deaths were caused by relapse in the first 6 months after SCT. In multivariate analysis, the single factor associated with better DFS was an interval between CR1 and SCT of less than 4 months (P: <.025). CONCLUSION: SCT is a valid option in the treatment of infant acute leukemia, and it may overcome the high risk of relapse with conventional chemotherapy showing very reduced toxicity. This study suggests that SCT should be performed in CR1 in the early phase of the disease.

Acute Disease↗
PubMed2000

Morphology and neurochemistry of two striatal neuronal subtypes expressing the GABA(A) receptor alpha3-subunit in the rat.

The morphological characteristics, distribution and neurochemical phenotype of striatal neuronal subtypes expressing the GABA(A) receptor alpha3-subunit were investigated using immunocytochemical and immunofluorescent techniques with an antibody specific for this subunit. alpha3-immunopositive neurons were infrequent in the rat striatum, but two morphologically different subtypes were observed: Cholinergic neurons, and a second cellular type that may correspond to neurogliaform neurons, although it may also be a novel subtype of striatal interneuron. To identify the second cellular subtype, co-localization of the GABA(A) receptor alpha3-subunit with markers of different classes of striatal interneurons was studied using specific antibodies. It was found that there was a lack of co-localization between all interneuronal markers used in this study and the alpha3-subunit. Although the alpha3-subunit immunopositive neurons represent a small percentage of the total of striatal neuronal populations, they may play an important role in the regulation of the microcircuitry of the striatum.

Animals↗
PubMed2000

Glucocorticoids antagonize AP-1 by inhibiting the Activation/phosphorylation of JNK without affecting its subcellular distribution.

The immunosuppressive and antiinflammatory actions of glucocorticoid hormones are mediated by their transrepression of activating protein-1 (AP-1) and nuclear factor-kappa B (NFkappaB) transcription factors. Inhibition of the c-Jun NH(2)-terminal kinase (JNK) signaling pathway, the main mediator of AP-1 activation, has been described in extracts of hormone-treated cells. Here, we show by confocal laser microscopy, enzymatic assays, and immunoblotting that the synthetic glucocorticoid dexamethasone inhibited tumor necrosis factor alpha (TNF-alpha)-induced phosphorylation and activation of JNK in the cytoplasm and nucleus of intact HeLa cells. As a result, c-Jun NH(2)-terminal domain phosphorylation and induction were impaired. Dexamethasone did not block the TNF-alpha-induced JNK nuclear translocation, but rather induced, per se, nuclear accumulation of the enzyme. Consistently with previous findings, a glucocorticoid receptor mutant (GRdim), which is deficient in dimerization, DNA binding, and transactivation, but retains AP-1 transrepressing activity, was as efficient as wild-type GR in mediating the same effects of dexamethasone on JNK in transfected Cos-7 cells. Our results show that glucocorticoids antagonize the TNF-alpha-induced activation of AP-1 by causing the accumulation of inactive JNK without affecting its subcellular distribution.

Animals↗
PubMed2000

Association of race and gender with HIV-1 RNA levels and immunologic progression.

CONTEXT: HIV-1 RNA and lymphocyte subset levels are the principal indications for antiretroviral treatment. Past reports have differed with regard to the effect of gender and race on these measures and in measures of disease progression. OBJECTIVE: To assess racial and gender differences in HIV-1 RNA levels and CD4+ lymphocyte decline. DESIGN: A longitudinal study based in the two largest HIV natural history cohort studies conducted in 7 metropolitan areas of the United States. RESULTS: In all, 1256 adult women and 1603 adult men for whom multiple data points were available prior to initiation of antiretroviral therapy were included. Women were more likely to be nonwhite, to have a history of injection drug use, and to have HIV-associated symptoms. After adjustment for differences in measurement method, baseline CD4+ cell count, age, and clinical symptoms, HIV-1 RNA levels were 32% to 50% lower in women than in men at CD4+ counts >200 cells/mm3 (p <.001) but not at CD4+ cell counts <200 cells/mm3. HIV-1 RNA levels were also 41% lower in nonwhites than in whites (p <.001) and 21% lower in persons reporting a prior history of injection drug use (p <.001). Women had more rapid declines in CD4+ cell counts over time than men (difference in slope of 46 cells/year) and nonwhite individuals had slower decline in CD4 cell counts than whites (difference of 39 cells/year). CONCLUSIONS: Both race and gender influence the values of HIV-1 RNA and the rate of HIV-1 disease progression as indicated by decline in CD4 cell counts over time. These effects could provide clues regarding the factors that influence HIV-disease progression and may indicate that guidelines for therapy should be adjusted for demographic characteristics.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Cervical neoplasia and repeated positivity of human papillomavirus infection in human immunodeficiency virus-seropositive and -seronegative women.

Increased risk for cervical intraepithelial neoplasia (CIN) in human immunodeficiency virus (HIV)-infected women may be explained by repeated positivity of human papillomavirus (HPV) infection facilitated by HIV infection and related immunosuppression. As part of a longitudinal study with semiannual examinations, 268 women in Baltimore, Maryland (of whom 184 were HIV+), provided 1,426 cervicovaginal lavage specimens tested for HPV DNA by a polymerase chain reaction-based assay between 1992 and 1998. HPV positivity and time to HPV clearance according to HIV serostatus and CD4+ cell count were compared using models for correlated binary data and survival analysis. Of the 187 participants who had at least one positive measurement, the probability of subsequent HPV positivity among HIV- women and HIV+ women with CD4+ > or =200 and <200 cells/microl was 47.5%, 78.7%, and 92.9% (p < 0.001). Within-women HPV results were correlated (i.e., clustered) in each group (p < 0.01). Compared with HIV-participants, the relative incidence of HPV clearance was 0.29 and 0.10 among HIV+ women with CD4+ > or =200 and <200 cells/microl (p < 0.001). At the end of follow-up, 11 women had biopsy-confirmed CIN. The association of HIV and CIN (p = 0.014) was fully explained by repeated HPV positivity induced by HIV infection (p = 0.648). Reversal of immunosuppression following potent antiretroviral therapy must be expected to have a dramatic impact on HIV-related CIN.

Adult↗
PubMed2000

Interaction of human immunodeficiency virus type 1 and human herpesvirus type 8 infections on the incidence of Kaposi's sarcoma.

To determine Kaposi's sarcoma (KS) risk related to timing of human immunodeficiency virus type 1 (HIV-1) and human herpesvirus type 8 (HHV-8) infections, stored longitudinal sera from 400 homosexual men with known dates of HIV-1 seroconversion (+/-4.5 months) were tested for HHV-8 antibody. Times from HHV-8 seroconversion to KS were compared for the 69 men who became infected with HHV-8 after acquiring HIV-1 to the 182 men who were HHV-8 seropositive before their HIV-1 infection. None developed KS before coinfection. HHV-8 seroconversion after HIV-1 infection increased the risk of KS (risk ratio, 2.55; 95% confidence interval, 1.06-6.10) compared with those infected with HHV-8 before HIV-1. The KS hazards in HHV-8-infected men increased by 60% (P<.001) for each year of HIV-1 infection. Faster CD4 cell loss and higher HIV-1 RNA levels significantly predicted KS. The quicker development of KS in men acquiring HHV-8 after HIV-1 and its association with CD4 slope argues that KS is more likely if HHV-8 infection occurs in an immunocompromised person.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Mortality of HIV-positive and HIV-negative heroin abusers as a function of duration of injecting drug use.

OBJECTIVE: To determine the incidence of mortality of injecting drug users as a function of the duration of injecting drugs and HIV status, and to assess how these effects vary according to age at initiation and calendar period (before and after 1992). METHODS AND DESIGN: Cohort of 376 intravenous heroin users admitted to detoxification between February 1987 and January 1990. SETTING: Patients referred from outpatient clinics of metropolitan Barcelona. Duration and characteristics of drug use were determined by interviews. Blood samples were collected during admission and analyzed for HIV, CD4+ cell count and different biologic parameters. Assessment of vital status and causes of death were obtained by hospital charts, death certificates, and autopsies. RESULTS: The study population consisted of 299 men and 77 women, whose mean age at entry was 26 years, mean duration of injecting drug use before admission 6.1 years; HIV seroprevalence at entry 70.2%. By the end of the follow-up (median 5.6 years), 21.8% of individuals had died (26.6% in HIV-positive, and 10.7% in HIV-negative injecting users). Based on Kaplan-Meier estimates, 10%, 20%, and 30% of HIV negative patients died by 8.7, 11.3 and 14.3 years, respectively, after initiating injecting drugs. The corresponding survival times for the seropositives were substantially lower: 6.6, 8.5, and 11.6 years, respectively. Overall, the survival time was significantly (p < .05) decreased by 22% in HIV-positive injecting drug users. Older age at initiation of injecting drug use was significantly (p < .05) associated with mortality in HIV-positive heroin users but it showed the opposite direction among HIV-negative people. Death rates in HIV-positive patients of the same duration of drug use were similar in periods before and after 1992 (relative hazard (RH) = 0.97; 95% confidence interval: 0.58-1.61). Although not statistically significant, the hazard of death in HIV-negative injecting drug users was substantially lower after 1992 (RH = 0.59). CONCLUSIONS: Before introduction of potent antiretroviral therapies, HIV infection further increased rates of mortality that had already been heightened by injecting drug use. Furthermore, HIV infection modifies the effect of age at initiation and eliminates the seemingly downward trend of mortality in HIV-negative people.

Adolescent↗
PubMed2000

Fenfluramine-induced increase in preproenkephalin mRNA levels in the striatum: interaction between the serotonergic, glutamatergic, and dopaminergic systems.

Fenfluramine (FE) is a halogenated amphetamine derivative that has been used in the treatment of obesity. It has been suggested that the effects of FE on the striatum are mediated by serotonergic mechanisms. However, several major afferent systems may be involved, and administration of FE may be useful to study interactions between these systems. In this work, the effects of FE on striatopallidal neurons and the possible involvement of the major striatal afferent systems were studied in rats by determination of FE-induced changes in striatal levels of preproenkephalin (PPE) mRNA using in situ hybridization. Injection of FE induced a significant increase (60%) in striatal levels of PPE mRNA. This increase was blocked by pretreatment with the D(1) dopamine receptor antagonist SCH-23390 or with the NMDA glutamate receptor antagonist MK-801, or by lesion of the serotonergic system with 5,7-dihydroxytryptamine or p-chlorophenylalanine. In 6-hydroxydopamine lesioned rats, the lesion-induced increase in PPE mRNA levels was not affected by injection of FE, but was reduced by simultaneous serotonergic deafferentation. The results suggest that the serotonergic, glutamatergic, and dopaminergic system interact to increase striatal PPE mRNA levels after FE administration.

5,7-Dihydroxytryptamine↗
PubMed2000

Regulation of the L1 cell adhesion molecule by thyroid hormone in the developing brain.

Thyroid hormone is essential for brain maturation, regulating neuronal differentiation and migration, myelination, and synaptogenesis. Mutations in the cell adhesion molecule L1 cause severe neurological abnormalities in humans. We studied the effect of thyroid hormone deprivation and administration on L1 expression. Northern and in situ hybridization studies showed that hypothyroidism induces a marked increase in L1 mRNA levels in the caudate putamen, cerebral cortex, amygdala, and some thalamic nuclei. L1 protein was overexpressed in embryonic and newborn hypothyroid rats in the caudate putamen, internal capsule, habenula, and neocortex. Later in development, an abnormally high L1 expression was found in the cortical and cerebellar white matter, corpus callosum, anterior commissure, thalamocortical projections, and striatal fiber tracts of hypothyroid animals. Thyroid hormone administration reversed the upregulation of L1 expression in vivo and in cultured cells. Thus, alterations of L1 expression may contribute to the profound abnormalities caused by hypothyroidism in the developing brain.

Animals↗
PubMed2000

GABAA receptor subunit expression in intrastriatal ventral mesencephalic transplants.

To compare the expression of GABAA receptor subunits in the normal substantia nigra and in fetal mesencephalic neurons ectopically transplanted into the dopamine-depleted striatum, we have employed single and double immunocytochemical approaches using tyrosine hydroxylase (TH) and alpha 1, alpha 2, alpha 3, and beta 2/3 GABAA receptor subunit specific antibodies. In the substantia nigra, alpha 1 and beta 2/3 GABAA receptor subunits were labeled in processes in the pars compacta (SNc) and, more intensely, in both somata and processes in the pars reticulata (SNr). There was no clear TH and alpha 1 or beta 2/3 colocalization, with the exception of some TH-immunoreactive (-ir) neurons that showed a weak immunoreactivity for beta 2/3. Sections immunolabeled for alpha 2 showed a faint diffuse labeling for this subunit both in the SNr and in the SNc. Scattered somata were immunopositive for alpha 2, and some of them were also TH-ir. The labeling for alpha 3 and TH showed that TH-positive neurons expressed intense alpha 3 immunoreactivity, although some TH-negative somata in the SNr expressed weak alpha 3 immunoreactivity. In the transplants, double immunostaining procedures showed that the labeling for alpha 1 or beta 2/3 appeared particularly concentrated in patches of intensely immunoreactive neuronal processes that surrounded TH-ir cells, but these processes were not TH-ir. In the case of alpha 2, diffuse immunostaining was observed all over the graft, with some scattered positive somata. Only a few of them were also TH positive. Sections immunoreacted for alpha 3 and TH revealed that TH-ir neurons expressed intense alpha 3 immunoreactivity, and that only a few TH-negative neurons were weakly positive for alpha 3. These results show that mesencephalic tissue ectopically grafted into the striatum develops a pattern of GABAA receptor expression similar to that normally expressed in situ, and particularly that the grafted dopaminergic neurons express similar GABAA receptors, including the alpha 3 subunit. This might be due to the similarity of GABAergic afferents to these neurons in the SNc and the graft, or that at the time of transplantation this expression had already been determined.

Animals↗
PubMed2000

Absence of estrogen receptor-beta expression in metastatic ovarian cancer.

OBJECTIVE: To evaluate the expression of estrogen receptor (ER)alpha and ERbeta mRNA and protein in normal ovarian tissue and primary and metastatic tumors. METHODS: Estrogen receptor alpha and ERbeta expression was studied in normal ovarian biopsies (n = 9) and primary (n = 8) and metastatic ovarian epithelial cancers (n = 8). Ovarian tissue was collected from surgical samples. Estrogen receptor alpha and ERbeta mRNA expression was compared by coamplification of the mRNA of the ERs. Expression was confirmed at the protein level by Western blot analysis using antibodies specific for each receptor. RESULTS: Among eight primary ovarian cancer samples, three had only ERalpha, two had only ERbeta, and three had both. All eight metastatic ovarian cancer tissues expressed only ERalpha mRNA and protein. Biopsies from normal ovaries had ERalpha and ERbeta mRNA and protein. Two of the ovarian epithelial cancer samples were paired and showed the same results. CONCLUSION: We found varying amounts of ERalpha and ERbeta in normal ovaries, lower levels of ERbeta expression in ovarian epithelial cancer primary tumors, and only ERalpha in metastatic tumors. Our findings indicate that a fundamental difference might exist between primary and metastatic cells, which could be caused by intrinsic or extrinsic factors that regulate ER gene expression.

Adenocarcinoma, Mucinous↗