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Biomedical subjects

P Muñoz

Publications and source records attributed to P Muñoz.

At least 127 records · Page 7Linked to original sources
PubMed1996

Recurrent pneumococcal bacteremia. A warning of immunodeficiency.

BACKGROUND: Recurrent pneumococcal infections are known to occur occasionally in patients with profound immune defects. We performed a case-control analysis of recurrent pneumococcal bacteremias). PATIENTS AND METHODS: The 547 episodes of Streptococcus pneumoniae bacteremia detected from January 1, 1985, to December 31, 1994, were reviewed. We selected all cases with more than 1 episode separated by 30 days or more ("cases") and compared each of them with 2 controls (patients with single episodes of pneumococcal bacteremia). RESULTS: Fifteen patients (2.8%) had 31 episodes of pneumococcal bacteremia. Except for multiple myeloma (P < .02), the underlying disease was remarkably similar among patients with single and recurrent episodes of pneumococcal bacteremia. However, among patients positive for human immunodeficiency virus infection, those who had recurrences were at a more advanced stage of their disease than those who did not. The presence of an ultimately fatal underlying condition was more frequent in case patients (P < .001). Overall, 47% of the patients with recurrences died during their second episode of pneumococcal bacteremia. CONCLUSIONS: Our data suggest that recurrence is more than anecdotal in patients with bacteremic infections caused by S pneumoniae (2.8%). We believe that recurrence is a warning sign of immunodeficiency. Patients with multiple myeloma, human immunodeficiency virus infection, solid organ tumors, and chronic liver disease with bacteremic pneumococcal infections should be offered antipneumococcal vaccine and other potentially preventive measures, despite doubts about their efficacy. This is justified by the high mortality rate associated with recurrent episodes (47%).

AIDS-Related Opportunistic Infections↗
PubMed1996

Expression and insulin-regulated distribution of caveolin in skeletal muscle. Caveolin does not colocalize with GLUT4 in intracellular membranes.

Caveolin is believed to play an important role in sorting processes, vesicular trafficking, transmembrane signaling, and molecular transport across membranes. In this study we have evaluated the expression and distribution of caveolin in skeletal muscle and its interaction with GLUT4 glucose carriers. Caveolin was expressed to substantial levels in muscle and its expression was regulated in muscle; aging and high fat diet enhanced caveolin expression in skeletal muscle and inversely, myogenesis down-regulated caveolin in L6E9 cells. Under fasting conditions, most of caveolin was found in intracellular membranes and the caveolin present in the cell surface was found in both sarcolemma and T-tubules. Insulin administration led to a redistribution of caveolin from intracellular high density membrane fractions to intracellular lighter density fractions and to the cell surface; this pattern of insulin-induced redistribution was different to what was shown by GLUT4. These results suggests that caveolin is a component of an insulin-regulated machinery of vesicular transport in muscle. Quantitative immunoisolation of GLUT4 vesicles obtained from different intracellular GLUT4 populations revealed the absence of caveolin which substantiates the lack of colocalization of intracellular GLUT4 and caveolin. This indicates that caveolin is not involved in intracellular GLUT4 trafficking in skeletal muscle.

Animals↗
PubMed1996

Monitoring mortality as an indicator of influenza in Catalonia, Spain.

STUDY OBJECTIVE: This study aimed to investigate the behaviour of two indicators of influenza activity in the area of Barcelona and to evaluate the usefulness of modelling them to improve the detection of influenza epidemics. DESIGN: Descriptive time series study using the number of deaths due to all causes registered by funeral services and reported cases of influenza-like illness. The study concentrated on five influenza seasons, from week 45 of 1988 to week 44 of 1993. The weekly number of deaths and cases of influenza-like illness registered were processed using identification of a time series ARIMA model. SETTING: Six large towns in the Barcelona province which have more than 60,000 inhabitants and funeral services in all of them. MAIN RESULTS: For mortality, the proposed model was an autoregressive one of order 2 (ARIMA (2,0,0)) and for morbidity it was one of order 3 (ARIMA (3,0,0)). Finally, the two time series were analysed together to facilitate the detection of possible implications between them. The joint study of the two series shows that the mortality series can be modelled separately from the reported morbidity series, but the morbidity series is influenced as much by the number of previous cases of influenza reported as by the previous mortality registered. CONCLUSIONS: The model based on general mortality is useful for detecting epidemic activity of influenza. However, because there is not an absolute gold standard that allows definition of the beginning of the epidemic, the final decision of when it is considered an epidemic and control measures recommended should be taken after evaluating all the indicators included in the influenza surveillance programme.

Disease Outbreaks↗
PubMed1996

Insulin-induced redistribution of GLUT4 glucose carriers in the muscle fiber. In search of GLUT4 trafficking pathways.

Insulin rapidly stimulates glucose transport in muscle fiber. This process controls the utilization of glucose in skeletal muscle, and it is deficient in various insulin-resistant states, such as non-insulin-dependent diabetes mellitus. The effect of insulin on muscle glucose transport is mainly due to the recruitment of GLUT4 glucose carriers to the cell surface of the muscle fiber. There is increasing evidence that the recruitment of GLUT4 carriers triggered by insulin affects selective domains of sarcolemma and transverse tubules. In contrast, GLUT1 is located mainly in sarcolemma and is absent in transverse tubules, and insulin does not alter its cellular distribution in muscle fiber. The differential distribution of GLUT1 and GLUT4 in the cell surface raises new questions regarding the precise endocytic and exocytic pathways that are functional in the muscle fiber. The current view of insulin-induced GLUT4 translocation is based mainly on studies performed in adipocytes. These studies have proposed the existence of intracellular compartments of GLUT4 that respond to insulin in a highly homogeneous manner. However, studies performed in skeletal muscle have identified insulin-sensitive as well as insulin-insensitive intracellular GLUT4-containing membranes. These data open a new perspective on the dynamics of intracellular GLUT4 compartments in insulin-sensitive cells.

Animals↗
PubMed1996

[Gastroenteritis due to Aeromonas in pediatrics].

OBJECTIVE: In recent years the incidence of gastroenteritis due to Aeromonas spp has increased significantly. The purpose of this study was to investigate the etiology and clinical manifestations of this disease. PATIENTS AND METHODS: In the period between 1986 and 1992, we found Aeromonas spp in seventy patients (88 samples) between 0 and 16 years of age. We were able to analyze 53 of these samples. RESULTS: Of all of the patients, 66% were males and 58.5% were younger than two years old. We found a pattern in the disease with 83% of the cases occurring in summer and autumn. The infection was polymicrobial in 43% of the patients. The clinical manifestations most often found were fever (71%), vomiting (62.5%) and abdominal pain (9.4%). Diarrhea was watery in 71.7% and 64% of the cases lasted less than a week. The number of stools was 5 to 10 per day in 58% of the patients. Forty patients (75.5%) required hospitalization, with the stay being longer than 10 days in 25%. There were 30% of the patients that required antibiotic therapy, mostly due to concomitant infections and not due to the diarrheic episodes, with all of them having a satisfactory evolution.

Acute Disease↗
PubMed1996

[Iodine in school children. Relationship with incidence of goiter, socioeconomic group and salt intake].

In order to evaluate iodine daily intake in 5-14 year-old school children urinary iodine excretion was measured in morning urinary samples of 134 school children. This value was corrected to microgram/ 24 h according to Jolin and Escobar del Rey's formula. Thyroid size was evaluated by two expert examiners following WHO criteria. Coincidence between both examiners was indispensable to establish goiter diagnosis. We evaluated urinary samples of 134 school children (117 normal and 17 goitrous). Urinary iodine excretion mean values were significantly different between Normal: 140.04 +/- 86.28 micrograms/24 h and Goitrous: 98.24 +/- 47.91 micrograms 24 h; p < 0.005). Goiter prevalence was found to diminish significantly when urinary iodine excretion was greater than 150 micrograms/24 h (p < 0.05). Similar mean urinary iodine excretion was observed in different socioeconomic groups. No significant differences were detected in the evaluation of two most common salt trademark consumer groups. In conclusion 1) iodoprophylaxis efficacy was assessed by urinary iodine excretion, a valid means to estimate iodine intake. Acceptable mean levels of iodine intake were found in the group under study, but the individual variability was important; 2) goitrous schoolchildren showed an iodine intake lower than normal and 3) the important variability observed in the evaluated data, the assessed relation between goiter and lower iodine intake, and the high frequency of insufficient iodine intake should justify a better control of iodoprophylaxis and a more widespread information dissemination among the population and perhaps iodine supplements in specific groups.

Adolescent↗
PubMed1995

The T-tubule is a cell-surface target for insulin-regulated recycling of membrane proteins in skeletal muscle.

(1) In this study we have determined the distribution of various membrane proteins involved in insulin-activated glucose transport in T-tubules and in sarcolemma from rat skeletal muscle. Two independent experimental approaches were used to determine the presence of membrane proteins in T-tubules: (i) the purification of T-tubules free from sarcolemmal membranes by lectin agglutination, and (ii) T-tubule vesicle immunoadsorption. These methods confirmed that T-tubules from rat skeletal muscle were enriched with dihydropyridine receptors and tt28 protein and did not contain the sarcolemmal markers dystrophin or beta 1-integrin. Both types of experiments revealed an abundant content of GLUT4 glucose carriers, insulin receptors and SCAMPs (secretory carrier membrane proteins) in T-tubule membranes. (2) Acute administration in vivo of insulin caused an increased abundance of GLUT4 in T-tubules and sarcolemma. On the contrary, insulin led to a 50% reduction in insulin receptors present in T-tubules and in sarcolemma, demonstrating that insulin-induced insulin receptor internalization affects T-tubules in the muscle fibre. The alteration in the content of GLUT4 and insulin receptors in T-tubules was a consequence of insulin-induced redistribution of these proteins. SCAMPs also redistributed in muscle membranes in response to insulin. They were recruited by insulin from intracellular high-density fractions to intracellular lighter-density fractions and to the cell surface, showing a pattern of insulin-induced cellular redistribution distinct from those of GLUT4 and the insulin receptor. (3) In conclusion, the T-tubule is a cell-surface target for membrane proteins involved in recycling such as SCAMPs or for membrane proteins that acutely redistribute in response to insulin such as GLUT4 or insulin receptors.

Animals↗
PubMed1995

Isolation and characterization of distinct domains of sarcolemma and T-tubules from rat skeletal muscle.

1. Several cell-surface domains of sarcolemma and T-tubule from skeletal-muscle fibre were isolated and characterized. 2. A protocol of subcellular fractionation was set up that involved the sequential low- and high-speed homogenization of rat skeletal muscle followed by KCl washing, Ca2+ loading and sucrose-density-gradient centrifugation. This protocol led to the separation of cell-surface membranes from membranes enriched in sarcoplasmic reticulum and intracellular GLUT4-containing vesicles. 3. Agglutination of cell-surface membranes using wheat-germ agglutinin allowed the isolation of three distinct cell-surface membrane domains: sarcolemmal fraction 1 (SM1), sarcolemmal fraction 2 (SM2) and a T-tubule fraction enriched in protein tt28 and the alpha 2-component of dihydropyridine receptor. 4. Fractions SM1 and SM2 represented distinct sarcolemmal subcompartments based on different compositions of biochemical markers: SM2 was characterized by high levels of beta 1-integrin and dystrophin, and SM1 was enriched in beta 1-integrin but lacked dystrophin. 5. The caveolae-associated molecule caveolin was very abundant in SM1, SM2 and T-tubules, suggesting the presence of caveolae or caveolin-rich domains in these cell-surface membrane domains. In contrast, clathrin heavy chain was abundant in SM1 and T-tubules, but only trace levels were detected in SM2. 6. Immunoadsorption of T-tubule vesicles with antibodies against protein tt28 and against GLUT4 revealed the presence of GLUT4 in T-tubules under basal conditions and it also allowed the identification of two distinct pools of T-tubules showing different contents of tt28 and dihydropyridine receptors. 7. Our data on distribution of clathrin and dystrophin reveal the existence of subcompartments in sarcolemma from muscle fibre, featuring selective mutually exclusive components. T-tubules contain caveolin and clathrin suggesting that they contain caveolin- and clathrin-rich domains. Furthermore, evidence for the heterogeneous distribution of membrane proteins in T-tubules is also presented.

Animals↗
PubMed1995

Cutaneous mucormycosis in a heart transplant patient associated with a peripheral catheter.

The first known case of an intravascular catheter-related primary cutaneous mucormycosis in a heart transplant patient is reported. The patient had corticosteroid-induced hyperglycemia and experienced an acute tissue rejection episode. A necrotic lesion appeared around the insertion site of a peripheral venous catheter. A biopsy revealed typical mucorales hyphae. The lesion continued to spread during the following 24 hours and necessitated amputation of the forearm. The organism was identified as a Mucor species.

Catheterization, Peripheral↗
PubMed1995

Tuberculosis in heart transplant recipients.

We present an analysis of the incidence, clinical presentation, and evolution of tuberculosis in heart transplant recipients at a 2,200-bed tertiary care center in Madrid and review the world literature. During a 5-year period (1989-1993), active extrapulmonary tuberculosis was diagnosed in three of the 144 patients who survived heart transplantation, resulting in an incidence of 1.35 cases per 100 heart transplant-years (> 20-fold the national average). The mean age of the patients was 52 years, and two were male. The mean time to development of tuberculosis after transplantation was 76 days (range, 55-102 days). All of the patients had had previous episodes of rejection and infection and had had initially negative tuberculin tests (one converted to positive during therapy). Clinical manifestations were mild or absent in two of the patients, and Mycobacterium tuberculosis was isolated in association with other microorganisms from two patients. All patients were successfully treated with antituberculous chemotherapy while they were receiving immunosuppressants. A severe drug interaction between cyclosporine and rifampin in the first case necessitated withdrawal of rifampin and precluded its use in subsequent patients. During a mean follow-up of 2 years, no recurrence of tuberculosis has been detected in any of the patients. Tuberculosis was diagnosed in a fourth patient before transplantation, which was performed while the patient was receiving antituberculous therapy. Our data support the conclusion that heart transplantation should be considered an unheralded risk factor for tuberculosis, particularly in countries where this disease is prevalent.

Antitubercular Agents↗
PubMed1995

Daily surface ozone maximum concentrations at Taliarte, Canary Islands.

Two different methods for using air quality data to estimate daily maximum concentrations along a year of surface ozone concentration in a new measurement station in Canary Islands are described. It is usually assumed that sequences of pollutant concentration show stationary behaviour. In this paper, it is shown that the application of such procedure could be useful to estimate probabilities of maximum concentration of surface ozone. Nevertheless, this method does not take into account the time structure of the original data, so that some caution should be taken into account. In this sense, an alternative procedure, assuming nonstationary behaviour of data, is developed to estimate empirically the probability distributional properties of the original series. Its application yields a substancial improve of the explanation of underlying series structure.

Models, Statistical↗
PubMed1995

[Infectious complications in patients undergoing a heart transplant].

Infectious complications are, with rejection, the main cause of morbidity and mortality in heart transplantation recipients. Adequate management of these patients requires an adequate knowledge of risk factors, of most common infectious syndromes and of relevant microorganism, as long as of their resistance pattern. Among the first group, we may mention lower respiratory tract infections, mediastinitis and meningitis, and among the microorganisms, Citomegalovirus, Aspergillus and Toxoplasma gondii. The impressive development of diagnostical techniques and of prophylactic and therapeutical possibilities suggest the convenience of a multidisciplinar approach to these complications.

Communicable Disease Control↗