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Biomedical subjects

A Mas

Publications and source records attributed to A Mas.

At least 19 recordsLinked to original sources
PubMed2005

Invasive pulmonary aspergillosis in solid organ and bone marrow transplant recipients.

BACKGROUND: Invasive pulmonary aspergillosis (IPA) remains a major cause of mortality in transplant recipients. New strategies in therapy are needed. METHODS: We prospectively followed all solid organ and bone marrow transplant recipients from January 1998 to January 2003 who showed pulmonary infiltrates. We retrospectively analyzed all of the patients diagnosed as having IPA. Clinical and epidemiological data were collected. Influence of new treatment strategies on survival was also analyzed. RESULTS: Thirty-one cases of API were found: 8 definite, 18 probable, 5 possible among recipients of liver (11), bone marrow (9), kidney (7), kidney-pancreas (3), and heart (1) transplants. Five patients (16%) were previously receiving antifungal prophylaxis. The most common symptoms were fever (74%) and dyspnea and dry cough (48%). Six cases (19%) showed dissemination to extrapulmonary sites: central nervous system (CNS) in five and bone in one. The most common radiographic patterns were alveolar infiltrates (58%); the lesions were usually diffuse and bilateral (58%). The most common Aspergillus species identified was A. fumigatus (74%). The test to detect Aspergillus antigen (galactomannan) in serum performed in 13 cases, was positive in eight (61%). The crude mortality rate was 61% (19 of 31), but in patients on mechanical ventilation, it was 94% (OR 88, IC 95%: 7.1-1094), and in patients with CNS involvement, it was 100%. The influence of the different treatment regimens on survival was analyzed in definite and probable cases: Group 1 (12) included patients who received conventional monotherapy and group 2 (12) patients received combination antifungal therapy or liposomal amphotericin B (1-AMB) at high doses. The mortality in group 1 was 83% (10 of 12), and in group 2 it was 42% (5 of 12) (P < 0.05). CONCLUSIONS: The mortality rate of IPA remains high, especially among patients with CNS involvement or those under mechanical ventilation. Combined antifungal therapy or monotherapy with 1-AMB at high doses significantly reduced mortality compared with conventional monotherapy.

Amphotericin B↗
PubMed2005

Study on the efficacy and safety of adefovir dipivoxil treatment in post-liver transplant patients with hepatitis B virus infection and lamivudine-resistant hepatitis B virus.

Hepatitis B virus (HBV) recurrence and de novo HBV infection are frequent events in liver transplantation recipients. Treatment with lamivudine is initially efficient in both infections but the incidence of lamivudine-resistant HBV emergence increases over time. Adefovir appears to be promising in post-liver transplantation patients with recurrent HBV infection and lamivudine-resistant HBV. This study analyzed adefovir treatment in 42 post-liver transplantation patients who developed recurrent HBV or de novo HBV infection with lamivudine-resistant HBV (54.8% HCV-coinfected). Patients received 10 mg of oral adefovir once daily for a mean period of time of 21.5 months (range from 12 to 31 months). In 62.9% of patients, ALT levels decreased significantly. Serum HBV-DNA was undetectable in 64% of the cases. Twenty percent of patients lost HBeAg marker and 13.3% of them developed anti-HBe. In 9.5% of recipients, HBsAg became negative. There was no significant change in serum creatinine levels. In only one patient was worsening of the renal function detected, making dose adjustment necessary. No other side effects were reported. Our results confirm the efficacy and safety of adefovir treatment in post-liver transplantation patients with lamivudine-resistant HBV, neither were adefovir-resistant mutations identified in patients after 21 months of therapy, nor were there adverse events, especially renal toxicity.

Adenine↗
PubMed2005

[Hypertransaminasemia greater than 400 U/l in adults seen at a tertiary hospital. Prospective study of etiology].

AIM: To investigate the frequency of distinct causes of elevated transaminase levels in the range of acute viral hepatitides in patients attended in a hospital. PATIENTS AND METHOD: Patients attended in a tertiary hospital over a 3-month period who had elevation of transaminase levels (aspartate aminotransferase [AST] or alanine aminotransferase [ALT]) above 400 U/l were identified and their medical records were reviewed to determine etiology. RESULTS: A total of 106 patients were studied, of which 22 had undergone liver transplantation. In these patients, the causes of hypertransaminasemia were ischemic/reperfusion injury in 6 (27%), ischemic hepatitis in 4 (18%), acute hepatitis in 2 (9%), cellular rejection in 3 (14%), chronic hepatitis C in 4 (18%) and cholestasis in 3 (14%). In the 84 patients who did not undergo transplantation, the causes were hepatic ischemia in 24 (28%), chronic viral hepatitis in 19 (22%), toxic hepatitis in 12 (14%), pancreatico-biliary disease in 11 (13%), acute viral or bacterial hepatitis in 10 (12%), liver tumor in 3 (4%), cholestasis of pregnancy in one and unknown in 4 (5%). Ischemic lesions and pancreatico-biliary disease were more frequent in hospitalized patients while acute and chronic hepatitides were more frequent in outpatients. The worst outcomes were found in ischemic lesions and pancreatico-biliary disease. CONCLUSION: Marked elevation of transaminase levels has multiple causes. Acute viral hepatitides were a relatively infrequent cause. In transplant recipients, the most frequent causes were ischemia/reperfusion injury, while in non-transplanted patients the most frequent causes were ischemic hepatitides and acute episodes of chronic viral hepatitides. The AST/ALT ratio did not contribute to etiologic diagnosis.

Adolescent↗
PubMed2004

[Evaluation of the influence of medical education on the smoking attitudes of future doctors].

OBJECTIVE: To evaluate whether medical education influences the prevalence, awareness of, and attitudes to smoking of medical students in the first 3 years of their degree. MATERIAL AND METHODS: In this descriptive longitudinal questionnaire-based study of university students, data for medical and veterinary students in their first 3 years were compared. RESULTS: Of the 226 registered first-year medical students, 181 (80%) returned the questionnaire. Of the 180 first-year veterinary students, 161 (89%) replied to the questionnaire. In the third year, 151 questionnaires from medical students and 139 from veterinary students were returned. There were no differences in age or sex between the 2 groups, and both had more women. The prevalence of smokers increased between the first year and the beginning of the third (from 20% to 31% among medical students and from 28% to 32% among veterinary students). An improvement in the awareness of smoking as a risk factor was observed for medical students, but no change in attitude was observed. CONCLUSIONS: The influence of medical education on this health concern is limited as there is no reduction in the prevalence of smoking. Medical education also seems unable to change attitudes to smoking. More students relate smoking to risk factors for certain diseases, showing greater awareness of the health problems caused by smoking.

Adult↗
PubMed2004

[Smoking habits among sixth-year medical students in Spain].

OBJECTIVE: To describe and analyze the smoking habits of sixth-year Spanish medical students. MATERIAL AND METHODS: The target population of this descriptive cross-sectional study was students completing their sixth year in Spanish medical schools. An anonymous, self-administered questionnaire was sent to the students' homes by ordinary mail. The relationships between the variables were analyzed using contingency tables, the chi2 test, the Student t test, and analysis of variance with a significance level of P< .05. The software package was SPSS. RESULTS: A total of 3840 questionnaires were distributed to students, and 1340 were returned completed (34.9%). Of the respondents, 27% were smokers (8.7% smoked only on weekends, and 18.3% were daily smokers). The mean (SD) number of cigarettes smoked per day was 10.54 (7.89). Consumption was significantly higher among men than among women. The mean age of initiation was 17.20 years. Of the students who were smokers, 32.54% stated that they had started smoking during their medical studies. The percentage of smokers who stated that they wanted to quit was 76.3%, and 56.6% said that they had already made at least one quit attempt. CONCLUSIONS: It is cause for concern that a large number of students start smoking after they enter medical school. One of the reasons for this is the lack of concern about smoking as a health problem within medical schools. The smoking habits of medical students are affected by the same phenomena that affect those of the general public, such as the increase in the number of women smokers, the influence of sociocultural factors, and the increasingly broader age range of initiation. The lower prevalence of smoking among medical students with respect to other populations is probably due to the fact that, in general, these students have better health habits than the general public, and/or the reasons that led them to study medicine also make them disinclined to smoke.

Adolescent↗
PubMed2004

Cerebrospinal fluid concentrations of idebenone in Friedreich ataxia patients.

We studied plasma and cerebrospinal fluid (CSF) concentrations of idebenone in five Friedreich ataxia patients on treatment with this antioxidant, and plasma and CSF ubiquinone-10 (Q (10)) concentrations in 15 controls. CSF idebenone concentrations were below the detection limit in 3 Friedreich ataxia patients and no association could be demonstrated between plasma and CSF idebenone values. Q (10) CSF concentrations (median: 2.25 nmol/L) were approximately 300 times lower than those of plasma (median: 0.77 micro mol/L). No correlation was observed between plasma and CSF Q (10) concentrations. A significantly positive correlation was observed between CSF total protein values (range 8.1 - 107.5 mg/dL; median: 29.5) and CSF Q (10) concentrations (Spearman test: r = 0.664; p = 0.01). Our findings suggest that less idebenone is distributed to the brain than to other tissues, although CSF does not appear to be an appropriate material for treatment monitoring of idebenone and other quinoid compounds.

Adolescent↗
PubMed2004

Application of molecular methods for the differentiation of acetic acid bacteria in a red wine fermentation.

AIMS: To apply rapid and reliable molecular techniques for typing acetic acid bacteria and studying their population dynamics during wine-making processes. METHODS AND RESULTS: We tested the usefulness of the Enterobacterial Repetitive Intergenic Consensus-PCR (ERIC-PCR) and Repetitive Extragenic Palindromic-PCR (REP-PCR) techniques with reference strains of most of the species of acetic acid bacteria. We obtained exclusive patterns for each strain with the ERIC-PCR technique, proving the utility for characterizing below species level. REP-PCR technique was not as adequate for this purpose because some strains yielded identical fingerprint. One hundred twenty isolates from a commercial red wine fermentation were fingerprinted using both techniques. We detected a high degree of strain diversity in the first stage of fermentation that decreased throughout the process. However, several strains and species were dominant in the alcoholic fermentation phases. The identification of different strains or genotypes at the species level was carried out by restriction analysis of the 16S ribosomal DNA gene. Gluconobacter oxydans dominated the fresh must, while Acetobacter aceti was the only isolated species at the end of the process. Gluconacetobacter hansenii and G. liquefaciens were also isolated in significant numbers at the beginning of fermentation. CONCLUSIONS: ERIC-PCR and REP-PCR techniques proved useful for characterizing strains of acetic acid bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: The availability of molecular techniques for a fast and reliable genotypic characterization should increase our knowledge of the ecology of acetic acid bacteria and determine more accurately their growth behaviour during various stages of vinification.

Acetic Acid↗
PubMed2004

New PCR-based methods for yeast identification.

AIMS: To characterize reference yeast strains and identify indigenous strains isolated from wine fermentations by PCR methods. METHODS AND RESULTS: We compared several PCR techniques for yeast identification. We used oligonucleotide primers that are complementary to (i) intron splice sites, (ii) REP and (iii) ERIC elements to produce PCR fingerprints that display specific patterns between the different yeast species. These three techniques were used to characterize 41 reference yeast strains belonging to 15 different species and to identify 40 indigenous strains isolated from grape must and wine fermentations. Species-specific banding patterns were obtained with the three PCR-techniques with different degrees of intraspecific differentiation depending on the method. By comparing the PCR fingerprints of unknown isolates with those produced by reference strains, we identified yeast strains isolated from an industrial wine fermentation. CONCLUSIONS: All three PCR techniques are rapid, reliable and simple methods of yeast identification. As far as we know, this is the first time that the primers designed for amplifying repetitive elements in bacteria have been successfully used in yeast. SIGNIFICANCE AND IMPACT OF THE STUDY: Industry needs rapid, reliable and simple methods of yeast identification. The proposed PCR techniques will allow to achieve this objective.

DNA Fingerprinting↗
PubMed2003

[Reliability of a questionnaire on smoking to evaluate prevalence, knowledge and attitudes of medical students].

OBJECTIVE: To evaluate the reliability and reproducibility of results obtained from a questionnaire on the smoking habits of medical students. METHOD: A questionnaire with 30 variables was designed to measure three main parameters: prevalence, knowledge and attitudes toward smoking. First-year medical students at the University of Zaragoza (1997-98 academic year) were asked to fill in the questionnaire, and a code was assigned to each individual respondent. A test-retest method was then used to assess reliability: the same questionnaire was answered by the subjects after a period of time had elapsed. The Kappa coefficient was calculated to measure agreement. RESULTS: The questionnaire was filled in by 181 students at registration and 7 weeks later by 43 students. The first- and second-time questionnaires for 35 individuals were matched by codes. Reliability was good for most variables related to the main characteristics of smoking (such as prevalence, number of cigarettes smoked daily and consonance-dissonance). Reliability was acceptable for most variables related to knowledge but was low for 3 items. Reliability was acceptable for half the items related to attitudes and low for half. CONCLUSIONS: The questionnaire has a generally good level of reliability, with regard to reproducibility, or the likelihood that an individual will respond to an item in the same way at two different times. Some variables that measure attitudes toward smoking, however, are less reliable. Results obtained for those items should therefore be interpreted cautiously.

Adult↗
PubMed2003

[Profile of smokers who seek treatment at a smoking cessation clinic].

OBJECTIVES: The variety of smoking cessation therapies that have proven effective ranges from simple counseling to intensive interventions. The objective of our study was to identify the characteristics of smokers who currently seek treatment at a smoking cessation clinic. METHODS: Descriptive observational study. The target population consisted of smokers who sought treatment at a smoking cessation clinic. The following variables were studied: sex; age; referral source; marital status; educational level; age at which smoking began, age at which it became a regular habit and the time elapsed between the two moments; level of nicotine dependence (Fagerström Test for Nicotine Dependence); number of cigarettes per day; number of years smoking; use of other potentially-addictive substances (alcohol, caffeine, psychotropic medications and other drugs); presence of concomitant disease; previous attempts to quit smoking; current reasons for smoking cessation; and concentration of expired air carbon monoxide (CO). An initial medical history was taken from each smoker on the waiting list for treatment at the clinic in order to gather data on the study variables; these individuals were then enrolled in a 3-month group smoking cessation program that utilized both medication and cognitive-behavioral therapy. The results are presented in percentages and means with standard deviations (SD) and 95% confidence intervals (CI). RESULTS: 385 smokers were studied--239 (62%) men and 146 (38%) women--the average age being 43.05 years (SD: 9.07). Mean nicotine-dependence (Fagerström Test score) was 6.05 (SD: 2.19); mean number of cigarettes per day: 25.9 (SD: 12.11); mean number of years as a smoker: 25.3 (SD: 9.04); and mean expired air CO: 39.30 (SD: 25.18). Associated disease was present as chronic bronchitis for 27.5% and cardiovascular risk factors for 15%. Previous attempts to quit smoking were reported by 72%; the reasons for the present attempt to quit smoking were the prevention of disease (38%), awareness of dependence (20%) and parental desire to serve as a positive role model for children (10%). CONCLUSIONS: At present, the smokers who attend a smoking cessation clinic are young, severely-dependent adults in the initial stage of preparing to quit. The prevalence of symptoms in this population is low. The profile of the population seeking specialized smoking cessation treatment is expected to change in the future as those with smoking-related diseases and other specific populations of smokers become included.

Adult↗
PubMed2002

Friedreich's ataxia: idebenone treatment in early stage patients.

BACKGROUND: Antioxidant therapy has been applied to Friedreich's ataxia patients. We assessed the effect of idebenone treatment in patients with Friedreich's ataxia. METHODS DESIGN: open-label trial. Nine Friedreich's ataxia patients (age range 11 - 19 years) were treated with idebenone (5 mg/kg/day). Patients were evaluated before the start of the therapy and throughout one year of treatment by International Cooperative Ataxia Rating Scales (ICARS) scores, neurophysiological investigations and echocardiographic measurements. Serum idebenone concentrations were measured by HPLC with electrochemical detection. The number of GAA repeats at the frataxin gene was analyzed by PCR. RESULTS: Serum idebenone concentrations ranged between 0.04 - 0.37 micro mol/L. Significantly positive correlation was observed between idebenone values and the percentage of difference between the ICARS scores before and 12 months after the start of the therapy (r = 0.883; p = 0.002). Significant reduction was observed comparing the ICARS scores in baseline conditions and after 3 months of treatment (p = 0.017). No differences were observed in echocardiographic measurements after the start of the therapy. CONCLUSIONS: Cerebellar improvement was notable in mild patients after the first 3 months of therapy. Idebenone treatment at early stages of the disease seems to reduce the progression of cerebellar manifestations. Further blind trials with a greater number of patients and higher doses are needed to fully assess the therapeutic potential of idebenone in Friedreich's ataxia.

Adolescent↗
PubMed2002

Primary human liver cells as source for modular extracorporeal liver support--a preliminary report.

Cell-based extracorporeal liver support is an option to assist or replace the failing organ until regeneration or until transplantation can be performed. The use of porcine cells or tumor cell lines is controversial. Primary human liver cells, obtained from explanted organs found to be unsuitable for transplantation, are a desirable cell source as they perform human metabolism and regulation. The Modular Extracorporeal Liver Support (MELS) concept combines different extracorporeal therapy units, tailored to suit the individual and intra-individual clinical needs of the patient. A multi-compartment bioreactor (CellModule) is loaded with human liver cells obtained by 5-step collagenase liver perfusion. A cell mass of 400 g - 600 g enables the clinical application of a liver lobe equivalent hybrid organ. A detoxification module enables single pass albumin-dialysis via a standard high-flux dialysis filter, and continuous veno-venuous hemodiafiltration may be included if required. Cells from 54 human livers have been isolated (donor age: 56 +/- 13 years, liver weight: 1862 +/- 556 g resulting in a viability of 55.0 +/- 15.9%). These grafts were not suitable for LTx, due to steatosis (54%), cirrhosis (15%), fibrosis (9%), and other reasons (22%). Out of 36 prepared bioreactors, 10 were clinically used to treat 8 patients with liver failure. The overall treatment time was 7-144 hours. No adverse events were observed. Initial clinical applications of the bioreactor evidenced the technical feasibility and safety of the system.

Bioreactors↗
PubMed2002

Extracorporeal liver support: porcine or human cell based systems?

Initial results of the clinical use of primary porcine liver cells for extracorporeal liver support are being reviewed as the cell source is controversial. According to Eurotransplant data 20-25% of explanted donor livers are not transplanted, due to factors such as steatosis or cirrhosis. This number corresponds to the number of patients with acute liver failure who require bridging therapy to transplantation. Primary human liver cells from transplant discards can be isolated, purified and maintained in bioreactors and provide an alternative for cell-based extracorporeal liver support therapy. A four-compartment bioreactor enables recovery from preservation and isolation injury in a three-dimensional network of interwoven capillary membranes with integrated oxygenation, rendering the liver cells from these discarded donor organs viable for clinical utilization. Patient contact with additional animal-derived biomatrix and fetal calf serum can be avoided. The initiation of an in vitro cultivation phase allows cell stabilization, quality control, and immediate availability of a characterized system without cryopreservation. The hypothesis of this paper is that with appropriate logistics and four-compartment bioreactor technology, cells from human liver transplant discards can serve the demand for cell-based therapy, including extracorporeal liver support.

Animals↗
PubMed2002

Stigma in mental illness: attitudes of medical students towards mental illness.

BACKGROUND: Negative attitudes towards people with mental illness can be attributed to stigma. The objective of this study was to determine the attitudes of medical students towards mental illness by comparing those who have had contact with mental patients and those who have not. This study also assesses to what extent knowledge about mental illness can affect the students' attitude. METHODS: A vignette and two dependent measures (social distance scale and dangerousness scale) were used to assess the attitudes of medical students towards mental illness. They comprised of 108 first year and 85 final year medical students in University of Malaya, Kuala Lumpur. The first year students didn't have any prior psychiatric training. RESULTS: The final year students who had knowledge and contact (undergone 8 weeks of clinical psychiatric training) were less stigmatizing toward mentally ill patients. There were no significant differences in the attitudes towards mentally ill patient among the first year students (no knowledge) regardless they had previous contact or not. CONCLUSION: Knowledge seems to have the effect in inculcating greater tolerance of mental illness. Contact by itself is not sufficient for attitude changes.

Attitude of Health Personnel↗
PubMed2001

[Bioartificial liver support for acute liver failure. First case treated in Spain].

BACKGROUND: Research aimed at developing artificial liver support systems has experienced a notable increase in the last decade. Hybrid systems including bioreactors containing hepatocytes which are perfused by liver failure patients blood or plasma have been deviced for the first time. The purpose of such a strategy is to substitute, at least in part, the impaired hepatic function thus improving the prognosis of patients with severe acute or chronic liver diseases. CASE REPORT: In the present paper, we report the first such a case treated in Spain in the context of a controlled, randomized, multicenter international study aimed at investigating the usefulness and safety of a bioartificial liver support system based on cryopreserved porcine hepatocytes in patients with acute liver failure or having a non-functioning primary graft after liver transplantation. RESULTS: In this first experience, two sessions of treatment could be completed before a patient with acute liver failure underwent a successful emergency liver transplantation. After more than two years of follow-up, the patient is in her normal life activities and she has not presented any adverse event related to the bioartificial liver support therapy so far. CONCLUSION: Bioartificial liver support systems are starting to be available for use in clinical practice. Yet it is mandatory to establish their safety and efficacy before a widespread recommendation.

Acute Disease↗
PubMed2001

Functional characterization of chimeric reverse transcriptases with polypeptide subunits of highly divergent HIV-1 group M and O strains.

Human immunodeficiency virus (HIV)-1 strains have been divided into three groups: main (M), outlier (O), and non-M non-O (N). Biochemical analyses of HIV-1 reverse transcriptase (RT) have been performed predominantly with enzymes derived from HIV-1 group M:subtype B laboratory strains. This study was designed to optimize the expression and to characterize the enzymatic properties of HIV-1 group O RTs as well as chimeric RTs composed of group M and O p66 and p51 subunits. The DNA-dependent DNA polymerase activity on a short heteropolymeric template-primer was similar with all enzymes, i.e. the HIV-1 group O and M and chimeric RTs. Our data revealed that the 51-kDa subunit in the chimeric heterodimer p66(M:B)/p51(O) confers increased heterodimer stability and partial resistance to non-nucleoside RT inhibitors. Chimeric RTs (p66(M:B)/p51(O) and p66(O)/p51(M:B)) were unable to initiate reverse transcription from tRNA(3)(Lys) using HIV-1 group O or group M:subtype B RNA templates. In contrast, HIV-1 group O and M RTs supported (-)-strand DNA synthesis from tRNA(3)(Lys) hybridized to any of their corresponding HIV-1 RNA templates. HIV-2 RT could not initiate reverse transcription on tRNA(3)(Lys)-primed HIV-1 genomic RNA. These findings suggest that the initiation event is conserved between HIV-1 groups, but not HIV types.

Base Sequence↗
PubMed2001

Virus population dynamics, fitness variations and the control of viral disease: an update.

Viral quasispecies dynamics and variations of viral fitness are reviewed in connection with viral disease control. Emphasis is put on resistance of human immunodeficiency virus and some human DNA viruses to antiviral inhibitors. Future trends in multiple target antiviral therapy and new approaches based on virus entry into error catastrophe (extinction mutagenesis) are discussed.

Anti-HIV Agents↗