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Biomedical subjects

J Ramos

Publications and source records attributed to J Ramos.

At least 55 records · Page 3Linked to original sources
PubMed1999

Acute hepatitis after riluzole administration.

Riluzole is a new drug representing the first active treatment for amyotrophic lateral sclerosis. We report the cases of two patients who developed acute hepatitis after taking riluzole at the recommended dose (100 mg daily) for 7 and 4 weeks, respectively. In both cases, liver histology showed hepatocellular damage with inflammatory infiltration and microvesicular steatosis without fibrosis. Liver enzymes returned to normal 4 and 8 weeks, respectively, after riluzole withdrawal. In one case, the readministration of riluzole was followed by the relapse of hepatitis. These two observations strongly suggest that riluzole can induce acute hepatitis with associated hepatocellular damage and microvesicular steatosis. They also suggest that liver enzymes should be monitored during treatment with riluzole.

Acute Disease↗
PubMed1999

[European Asthma Study. Identifying and treating young adults with epidemiological criteria for asthma in five areas of Spain. Spanish Group of the European Asthma Study].

BACKGROUND AND OBJECTIVES: Asthma's great impact on public health stems from its chronicity and to high prevalence among all age groups and both sexes. To estimate the appropriateness of treatment and management of asthma in Spain during the period of 1991 and 1992, we analyzed data from the European Community Respiratory Health Survey (ECRHS). METHOD: The ECRHS was undertaken with a random sample of 20-to-44-year-olds in Albacete, Barcelona, Galdakao, Huelva and Oviedo. In total, 181 individuals with asthma were identified. Current asthma was defined as the presence of respiratory symptoms associated with asthma within the past 12 months and a positive methacholine challenge test. RESULTS: Subjects who were unaware of having asthma made up 57.5% (CI: 49.9-64.8%), and 35.9% (CI: 27.9-42.3%) were not following any specific treatment. Among asthmatics who reported having continuous or frequent respiratory symptoms, 25.9% (CI: 15.3-39.0%) were not following any treatment. CONCLUSION: Over half the individuals with asthma in 1991 to 1993 were unaware of having the disease at the time of the study or of ever having had it, and approximately one third were not in treatment. The delivery of appropriate treatment in asthma generally, and in asthma with continuous or frequent respiratory symptoms, was markedly inadequate during the period studied.

Adult↗
PubMed1999

Pulp and paper from blue agave waste from tequila production.

Pulping of blue agave waste, from the production of tequila, was evaluated by both chemical and biomechanical pulping processes. Two conventional and two organosolv systems were used to pulp the agave waste under a standard set of conditions. The soda-ethanol process was superior in terms of delignification and pulp properties in comparison to the soda and ethanol organosolv processes for pulping of agave waste; however, the kraft process gave the best strength properties. In general, the strength of the agave waste pulps was rather poor in comparison to wood and other agro-based pulps; however, the tear strength was relatively high. This result is typical of poorly bonded sheets and may be due to the coarseness of the agave fibers and/or loss of hemicelluloses in the steaming process for the tequila production. Fungal treatment of the agave waste with Ceriporiopsis subvermispora reduced the energy consumption for mechanical refining but gave biomechanical pulps with inferior strength properties. The blue agave chemical pulps should be suitable for blending with softwood kraft pulps for publication grade paper.

Alcoholic Beverages↗
PubMed1999

Fps1p controls the accumulation and release of the compatible solute glycerol in yeast osmoregulation.

The accumulation of compatible solutes, such as glycerol, in the yeast Saccharomyces cerevisiae, is a ubiquitous mechanism in cellular osmoregulation. Here, we demonstrate that yeast cells control glycerol accumulation in part via a regulated, Fps1p-mediated export of glycerol. Fps1p is a member of the MIP family of channel proteins most closely related to the bacterial glycerol facilitators. The protein is localized in the plasma membrane. The physiological role of Fps1p appears to be glycerol export rather than uptake. Fps1 delta mutants are sensitive to hypo-osmotic shock, demonstrating that osmolyte export is required for recovery from a sudden drop in external osmolarity. In wild-type cells, the glycerol transport rate is decreased by hyperosmotic shock and increased by hypo-osmotic shock on a subminute time scale. This regulation seems to be independent of the known yeast osmosensing HOG and PKC signalling pathways. Mutants lacking the unique hydrophilic N-terminal domain of Fps1p, or certain parts thereof, fail to reduce the glycerol transport rate after a hyperosmotic shock. Yeast cells carrying these constructs constitutively release glycerol and show a dominant hyperosmosensitivity, but compensate for glycerol loss after prolonged incubation by glycerol overproduction. Fps1p may be an example of a more widespread class of regulators of osmoadaptation, which control the cellular content and release of compatible solutes.

Biological Transport↗
PubMed1999

The Schizosaccharomyces pombe Pzh1 protein phosphatase regulates Na+ ion influx in a Trk1-independent fashion.

We have previously shown that fission yeast encodes a PPZ-like phosphatase, designated Pzhl, which is an important determinant of cation homeostasis. pzh1 delta mutants display increased tolerance to Na+ ions, but they are hypersensitive to KC1 [Balcells, L., Gómez, N., Casamayor, A., Clotet, J. & Ariño, J. (1997) Eur. J. Biochem. 250, 476-483]. We have immunodetected Pzh1 in yeast extracts and found that this phosphatase is largely associated with particulate fractions. Cells defective in Pzh1 do not show altered efflux of Na+ or Li+ ions, but they accumulate these cations more slowly than wild-type cells. K+ ion content of pzh1 delta cells is about twice that of wild-type cells, and this can be explained by decreased efflux of K+. Therefore, Pzh1 may regulate both Na+ influx and K+ efflux in fission yeast. To test the possible relationship between K+ uptake, Na+ tolerance and Pzh1 function, we deleted the trk1+ gene, which encodes a putative high-affinity transporter of K+ ions. trkl delta mutants grew well even at relatively low concentrations of KCl and did not show significantly altered content or influx of K+ ions. However, they showed a Na(+)-sensitive phenotype which was greatly intensified by deletion of the sod2+ gene (which encodes the major determinant for efflux of Na+ ions), and clearly ameliorated by deletion of the pzh1 phosphatase, as well as by moderate concentrations of KCl in the medium. These results suggest that Trk1 does not mediate the effect of Pzh1 on NaCl tolerance and that fission yeast contains efficient systems, other than Trk1, for uptake of K+ ions.

Biological Transport↗
PubMed1999

Management of intraductal papillary mucinous tumours of the pancreas.

OBJECTIVE: To focus attention on the management and outcome of patients with intraductal papillary mucinous tumours of the pancreas. DESIGN: Retrospective study and analysis of published reports. SETTING: University hospital, France. SUBJECTS: 111 patients (101 published cases and our own 10 cases) divided in two groups: the first including malignant tumours (n = 46), and the second group benign or in situ tumours (n = 61). In 4 patients the type of tumour was not known. MAIN OUTCOME MEASURE: Resectability, mortality and recurrence. RESULTS: More men had benign or in situ tumours [48/61 (79%) compared with 28/46 (61%), p = 0.054]. Pancreatitis was more common among benign than malignant tumours [34/61 (58%) compared with 21/46 (46%), p = 0.33]. In group I, 39 patients had diabetes. A total of 107 patients were operated on: pancreaticoduodenectomy (n = 54, 50%), distal pancreatectomy (n = 25, 23%), total pancreatectomy (n = 4,4%), bypass (n = 2,2%). The type of resection was not mentioned in 22 records (21%). Four patients were not operated on because of their poor general condition. The resectability rate was 98% (105/107). Eleven patients had died at the time of publication. Hospital mortality rate was 3% (n = 3), mainly because 2 of the 4 who had total pancreatectomy died. With a median follow-up of 37 months, recurrence was 5% (n = 5). CONCLUSION: Intraductal papillary mucinous tumours of the pancreas are well known distinctive pancreatic tumours that are usually intraductal but may develop into invasive carcinoma. They should be resected, and have a good prognosis and low recurrence rate.

Adult↗
PubMed1999

Biochemical and genetic analyses of the role of yeast casein kinase 2 in salt tolerance.

Saccharomyces cerevisiae cells lacking the regulatory subunit of casein kinase 2 (CK-2), encoded by the gene CKB1, display a phenotype of hypersensitivity to Na(+) and Li(+) cations. The sensitivity of a strain lacking ckb1 is higher than that of a calcineurin mutant and similar to that of a strain lacking HAL3, the regulatory subunit of the Ppz1 protein phosphatase. Genetic analysis indicated that Ckb1 participates in regulatory pathways different from that of Ppz1 or calcineurin. Deletion of CKB1 increased the salt sensitivity of a strain lacking Ena1 ATPase, the major determinant for sodium efflux, suggesting that the function of the kinase is not mediated by Ena1. Consistently, ckb1 mutants did not show an altered cation efflux. The function of Ckb1 was independent of the TRK system, which is responsible for discrimination of potassium and sodium entry, and in the absence of the kinase regulatory subunit, the influx of sodium was essentially normal. Therefore, the salt sensitivity of a ckb1 mutant cannot be attributed to defects in the fluxes of sodium. In fact, in these cells, both the intracellular content and the cytoplasm/vacuole ratio for sodium were similar to those features of wild-type cells. The possible causes for the salt sensitivity phenotype of casein kinase mutants are discussed in the light of these findings.

Adenosine Triphosphatases↗
PubMed1999

[Non-invasive mechanical ventilation in patients with severe stable COPD].

BACKGROUND: The benefits of non-invasive mechanical ventilation (NIMV) in hypercapnic patients with severe stable COPD remain controversial mainly due to their unknown mechanisms. AIM: To assess the clinical and physiological benefits of a 3 weeks period of intermittent NIMV and their underlying mechanisms in COPD patients. PATIENTS AND METHODS: Twelve patients (10 male) prospectively recruited (age 65 +/- 3 years, FEV1 27 +/- 2% predicted, PaO2 46 +/- 2 mmHg, PaCO2 55 +/- 2 mmHg) were submitted to NIMV using a commercially available system (BiPAP) 3 h a day, 5 days a week for 3 weeks. Arterial blood gases, 6 min walking distance, dyspnea (Mahler's scale), breathing pattern, PIMax, ventilatory drive (P0.1) and the impedance of the respiratory system (P0.1/V1/T1) were measured before and after NIMV. RESULTS: A significant improvement in PaO2, PaCO2, PIMax, dyspnea and exercise capacity was observed in addition to a trend for VT to increase and for respiratory rate (RR) to decrease. The impedance of the respiratory system showed a significant reduction. Ventilatory drive, normalized for PaCO2 levels, did not change. Improvement in PaCO2 was related to an increase in Vp whereas a significant association between the reduction in RR and the fall in respiratory system impedance was also found. CONCLUSIONS: Our study supports previous data demonstrating that NIMV improves clinical and physiologic parameters in advanced stable COPD and suggest that the underlying mechanism is a reduction in the inspiratory load. A randomized clinical trial is needed to confirm that this mechanism is operative.

Aged↗
PubMed1998

[European study of asthma. Prevalence of atopy in young adults of 5 areas in Spain. Spanish Group of European Asthma Study].

BACKGROUND: The aim of the current study is to show the prevalence of atopy in five Spanish areas, and its variability according to area, age and gender. PATIENTS AND METHODS: From a populational based sample of 16,884 individuals aged 20 to 44 years-old, we obtained a randomized 20% subsample (n = 3,310). Participants performed specific IgE measurements, skin prick tests, forced spirometries and metacholine challenges to measure bronchial hyperresponsiveness. The response rate was 40%, and 1,313 individuals were finally included in the study. Specific atopy to the following aeroallargens was determined: cat dander, Cladosporium, Dermatophagoides, Phleum, Parietaria, birch, Alternaria, ambrosia, olive, rye grass and dog dander. RESULTS: The global prevalence of atopy (detectable specific antibodies IgE in serum and/or skin reactivity) widely varied by area, skin reactivity ranking in males from a minimum in Albacete (24.6%; 95% CI: 18-33) to a maximum in Huelva (39.6%; 95% CI: 30-53), and in females ranking from a minimun in Galdakao (10.3%; 95% CI: 6-17) to a maximum in Barcelona (28.8%; 95% CI: 19-43). Considering separately seropositivity and skin reactivity we observed a similar trend. Males showed a higher prevalence of global atopy (40.1%) than females (29.4%). Our data indicate that there is a decrease in the prevalence of atopy according to age in the general population, but only significant in men. Dermatophagoides pteronyssinus is the most common allergen in all ares but Albacete, where the most common allergen is the olive pollen. CONCLUSIONS: By means of a standard methodology, we report population data of the prevalence of atopy in five Spanish areas. The distribution of the prevalence of atopy varies widely in the five areas surveyed, according to the composition of the most common environmental allergens.

Adult↗
PubMed1998

The Pzh1 protein phosphatase and the Spm1 protein kinase are involved in the regulation of the plasma membrane H+-ATPase in fission yeast.

We have previously shown that the mutation of the Schizosaccharomyces pombe PPZ-like protein phosphatase encoded by the gene pzh1+ results in increased tolerance to sodium and in hypersensitivity to potassium ions. A similar phenotype has also been reported for deletants in the spm1/pmk1 gene, encoding a mitogen-activated protein (MAP) kinase. We have found that the sodium tolerance phenotype of pzh1 deletants is stronger than that of spm1 mutants, and both effects are additive. Therefore, most probably both gene products mediate different pathways on sodium tolerance. In our hands, mutation of the kinase does not alter the tolerance to potassium, but it yields cells more tolerant to magnesium ions. While in budding yeast the mutations are synthetically lethal, fission yeast cells lacking both the phosphatase and the kinase genes are viable. Interestingly, their ability to export H+ to the medium is greatly impaired (although not that of pzh1 or spm1 single mutants). We have observed that, although the amount of the H+-ATPase in the plasma membrane is not altered, the activity of the enzyme is lower than normal and cannot be induced by glucose. These observations suggest that the activity of the H+-ATPase in fission yeast might be regulated by phospho-dephosphorylation mechanisms that might involve the pzh1+ and spm1+ gene products.

Biological Transport↗
PubMed1998

Ectopic potassium uptake in trk1 trk2 mutants of Saccharomyces cerevisiae correlates with a highly hyperpolarized membrane potential.

Null trk1 trk2 mutants of Saccharomyces cerevisiae exhibit a low-affinity uptake of K+ and Rb+. We show that this low-affinity Rb+ uptake is mediated by several independent transporters, and that trk1Delta cells and especially trk1Delta trk2Delta cells are highly hyperpolarized. Differences in the membrane potentials were assessed for sensitivity to hygromycin B and by flow cytometric analyses of cellular DiOC6(3) fluorescence. On the basis of the latter analyses, it is proposed that Trk1p and Trk2p are involved in the control of the membrane potential, preventing excessive hyperpolarizations. K+ starvation and nitrogen starvation hyperpolarize both TRK1 TRK2 and trk1Delta trk2Delta cells, thus suggesting that other proteins, in addition to Trk1p and Trk2p, participate in the control of the membrane potential. The HAK1 K+ transporter from Schwanniomyces occidentalis suppresses the K+-defective transport of trk1Delta trk2Delta cells but not the high hyperpolarization, and the HKT1 K+ transporter from wheat suppresses both defects, in the presence of Na+. We discuss the mechanism involved in the control of the membrane potential by Trk1p and Trk2p and the causal relationship between the high membrane potential (negative inside) of trk1Delta trk2Delta cells and its ectopic transport of alkali cations.

Biological Transport↗
PubMed1998

[Acute hepatitis due to ecstasy].

BACKGROUND: Ecstasy is a synthetic amphetamine which causes a wide variety of adverse effects. Hepatic toxicity was only recently demonstrated but can be quite severe. CASE REPORT: A 27-year-old male with no past medical or surgical history developed jaundice without fever. He was a regular user of ecstasy and had recently increased the number of doses consumed. No evidence of a viral, alcoholic, metabolic or autoimmune mechanism was found which could explain the hepatitis. Complete cure was obtained by discontinuing ecstasy. DISCUSSION: Few cases of ecstasy hepatic toxicity have been reported. Ecstasy was undoubtedly the causal agent in this case since other known causes of acute hepatitis were excluded, confirming the hepatotoxicity of ecstasy reported in the literature. The liver disease has been reported to range form acute regressive hepatitis to fatal liver failure. Iterative exposure can lead to fibrosis. The pathophysiological mechanism of this toxic effect is not well elucidated. Ischemia alone cannot explain all the clinical forms described, particularly cases without hyperpyrexia. Ecstasy must be added to the list of potential causes of acute hepatitis. Exposure must always be searched for in cases of acute hepatitis in young subjects.

Acute Disease↗
PubMed1998

Prevalence of antiphospholipid antibodies in patients with chronic liver disease related to alcohol or hepatitis C virus: correlation with liver injury.

Antiphospholipid antibodies (APAs) have been reported in various clinical conditions. However, the pathogenesis and clinical significance of these antibodies are still unclear. The objective of this study was to assess the prevalence of APAs in patients with chronic alcohol- or hepatitis C virus (HCV)-related liver disease and to evaluate their relation to the underlying liver disease. We prospectively studied 201 patients referred to an hepato-gastroenterology department, including 77 patients with a history of alcohol abuse (group I) and 124 with chronic HCV infection (group II), and 107 healthy subjects (control population). Liver biopsy was performed in all patients. In cirrhotic patients, the severity of the liver disease was assessed with the use of Child's classification, as modified by Pugh. Several biologic parameters, including lupus anticoagulant and anticardiolipin antibodies, were determined. Forty-eight percent of patients in group I and 33% of those in group II had APAs. Among cirrhotic patients, APAs were more frequent in patients with Child grade B or C than in those with grade A severity. In patients with chronic HCV-related liver disease, a correlation was found between APA levels and liver fibrosis (P = 0.009); no relation was found between APA levels and histologic liver disease activity (P = 0.25). In the control group, one subject was APA-positive. None had lupus anticoagulant. APAs seem to be frequently associated with chronic liver disease of various causes. These results suggest further investigations on the potential role of these antibodies in fibrosis or liver injury.

Adult↗
PubMed1998

Dengue virus in the brain of a fatal case of hemorrhagic dengue fever.

Neurologic complications associated with dengue fever are in general unusual. However, recent reports evidence more frequent neurologic alterations. In Mexico, neurologic involvement has not been reported in dengue cases. This report demonstrates the detection of dengue virus in the brain of a fatal case of dengue hemorrhagic fever. Serotype 4 was detected by immunohistochemistry and by RT-PCR in the inferior olivary nucleus of medulla and in the granular layer of cerebellum. Immunoreactivity was observed in neurons, astrocytes, microglia and endothelial cells. Our results emphasize the importance of neurologic manifestations in patients with dengue fever.

Adolescent↗