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Biomedical subjects

J Solsona

Publications and source records attributed to J Solsona.

8 recordsLinked to original sources
PubMed2001

Estimation of kinetic rates in batch Thiobacillus ferrooxidans cultures.

In this work, the key problem of estimation in bioprocesses when no structural model is available is dealt with. A nonlinear observer-based algorithm is developed in order to estimate kinetic rates in batch bioreactors. The algorithm uses the measurements of biomass concentration and either substrate concentration or redox potential to perform the estimation of the respective specific kinetic rates. For this purpose, a general mathematical model description of the process is provided. The estimation algorithm design is based on a nonlinear reduced-order observer. The observer performance is validated with experimental results on a Thiobacillus ferrooxidans batch culture.

Algorithms↗
PubMed2001

Screening for tuberculosis upon admission to shelters and free-meal services.

BACKGROUND: The homeless are at very high risk of suffering tuberculosis (TB). The aims of this study were to determine the prevalence and risk factors for tuberculosis infection and disease among the homeless in Barcelona and to evaluate the roles of case finding and contact investigation. METHODS: Observational prevalence study carried out between 1997 and 1998. PARTICIPANTS: 447 homeless patients (394 men and 53 women) were evaluated before admission to shelters and free-meal services. At the same time, 48 co-residents with smear-positive TB patients in 2 long-term shelters were evaluated too. A chest X-ray and Tuberculin Skin Test were performed on all subjects. Sputum smears were processed by the Ziehl-Neelsen and Löwenstein-Jensen procedures in patients with radiographic findings consistent with pulmonary TB. RESULTS: Of the 447 homeless examined, 335 (75%) were infected with Mycobacterium tuberculosis. Active pulmonary TB was diagnosed in five persons (1.11%), and 62 (13.8%) had radiographic evidence of inactive pulmonary TB. Tuberculosis infection was associated with age and smoking, but not with sex or alcohol abuse. No significant differences in infection rates were found between the main group and 48 homeless co-residents of smear-positive subjects. Only 16.9% of the homeless with active TB in Barcelona in the same period were diagnosed through active case-finding, the remainder being mainly detected in hospitals (69.8%) and other several centres (13.3%). CONCLUSIONS: Homeless individuals have a very high risk of TB infection and disease and contact investigation requires specific methods for them. Programmes of screening and supervised treatment should be ensured in this group.

Adolescent↗
PubMed2001

Molecular and conventional epidemiology of tuberculosis in an inner city district.

SETTING: Molecular epidemiology has underlined the importance of recent tuberculosis (TB) transmission and has uncovered notable discrepancies compared with conventional epidemiology. OBJECTIVES: 1) To determine, by RFLP analysis, the percentage of clustered cases in an inner city district with a high incidence of TB (163/100,000) and the groups at risk of being clustered; and 2) to compare the role of conventional contact tracing (CCT) with that of RFLP. DESIGN: RFLP was carried out using the IS6110 and pTBN12 (PGRS) sequences of 165 cultures positive for Mycobacterium tuberculosis in the Ciutat Vella district of Barcelona during 1997-1998. Contact tracing was carried out in 171 of 251 declared cases (68.1%). Associations were assessed by calculating odds ratios (OR) with 95% confidence intervals (CI). Logistic regression was used for multivariate analysis. RESULTS: Using RFLP, 76 (46.0%) strains were found to be clustered by IS6110 and PGRS. From CCT, 30 new patients were found among 858 contacts (3.5%) and 57 patients were linked. In terms of RFLP and CCT, the main risk factor was intravenous drug use (IVDU). In 44 cases who lived alone and were not involved in CCT, 50% were in RFLP clusters. The concordance rate between RFLP and CCT was 8/13 (61.5%); the disagreement corresponded to a cluster of five recent immigrants from Africa. Subsequent to RFLP, an epidemiological connection was found in 15/55 cases (27.2%). CONCLUSIONS: The percentage of clustered cases is very high. CCT was useful for identifying new cases, but it was insufficient for detecting the pathways of transmission. CCT coverage needs to be improved in marginalized individuals, and the results correlated with those of RFLP.

Adolescent↗
PubMed2000

Diagnostic efficacy of the study of contacts of tuberculosis patients in a high prevalence urban area.

BACKGROUND: The investigation of contacts (CI) is a main objective for the control of tuberculosis (TB) after therapeutic compliance. The present study was planned to determine the diagnostic effectiveness and degree of CI implementation as well as risk factors to generate new cases in a high prevalence area (163/10(5)). PATIENTS AND METHODS: An analysis was made of the available data of CI in the Barcelona district of Ciutat Vella in 1997 and 1998. The odds ratio (OR) was calculated as a measure of the association with infection and tuberculosis disease with a 95% confidence interval (CI) by logistic regression. RESULTS: CI was made in 65.2% of patients and 100% of tuberculin-positive children. Thirty patients were diagnosed among 858 contacts of 135 tuberculosis patients (3.49%) and 8 among 318 contacts of 64 primoinfected children aged less than 15 years (2.51%). Prevalence of tuberculosis infection was 51.51% and 46.85%, respectively. The characteristics of the index case associated with new patients were drug abuse (OR: 11.16; CI: 3.0-40.9) and to be prisoner (OR: 18.7; CI: 1.5-232.9). No influence was detected regarding sputum acid-fast smears and degree of closeness except for contacts aged less than 20 years. CONCLUSIONS: CI is cost-effective in this area of high prevalence and should be performed in every TB case although priority groups are prisoners and/or drug abusers and contacts aged less than 20 years. The implementation of CI can be improved in our setting.

Adult↗
PubMed1981

Changes in circulating glycerol, free fatty acids and glucose levels following liver transplant in the pig.

Female pigs, fasted overnight, received an orthotopic liver transplant. During the nonhepatic phase, both blood glycerol and plasma free fatty acid concentrations increased, returning to basal values after the transplant, indicating that the liver is the main receptor of these products released in the blood from the glyceride breakdown in peripheral fat deposits. Blood glucose level rose during the nonhepatic phase, probably due in part to the perfusion of glucosated saline received by the animals during this phase. After liver transplant, blood glucose levels progressively decreased and this effect was greatly reduced by administering L-alanine. Our data indicate that metabolic changes in the donor's liver diminish the availability of gluconeogenetic substrates immediately following transplant, while administration of exogenous alanine permits faster restoration of gluconeogenetic function in the transplanted liver.

Animals↗
PubMed1977

Intrahepatic vascular division in the pig: basis for partial hepatectomies.

Transplantation of resected hepatic fragments, with the attendant vascular and biliary tract reconstruction, presents difficulties. We have studied the intraparenchymal vascular division in the pig with a view to performing partial hepatectomies with the greastest possible anatomical support. Forty-six molds of the various vascular territories were obtained from the 31 porcine livers. Each segment of the median lobe is dependent on the adjacent lateral lobe. Its intersegmental fissure is the obligatory site for parenchymal section to be continued through horizontal portion of portal vein, hepatic artery, and left hepatic duct. A right hemihepatectomy unfailingly results in the devitalization of the left side of the liver. If the goal of a hepatectomy is the transplantation of the resected fragment, it is recommended that the right side of the liver be utilized, as its more convenient extrahepatic vascular and biliary calibre will permit pedicular conservation and anastomosis.

Animals↗