PubMed Health⌕ Search

Biomedical subjects

P Cabrera

Publications and source records attributed to P Cabrera.

At least 19 recordsLinked to original sources
PubMed2001

Epidemiological evidence of the spread of a Mycobacterium tuberculosis strain of the Beijing genotype on Gran Canaria Island.

Molecular epidemiological studies suggest that particular Mycobacterium tuberculosis strains have an enhanced capacity to spread within a community. One strain, the Beijing genotype, has been associated with outbreaks in a number of communities throughout the world. IS6110 restriction fragment length polymorphism (RFLP) analysis was performed on M. tuberculosis isolates from 566 of the 721 patients (78.5%) diagnosed with tuberculosis (TB) on Gran Canaria Island from 1993 to 1996, as well as 35% of isolates from 1991-1992 (85 strains). RFLP identification of the family of strains of the Beijing genotype was confirmed by spoligotyping. Medical records of all patients were reviewed and epidemiological links were identified. Of 566 M. tuberculosis isolates from 1993 to 1996 with RFLP available, 72% belonged to clusters. The largest contained 75 cases and was caused by a strain of the Beijing genotype that was introduced to the island in 1993. It was found in 10 patients in 1993 (5.5%), 12 in 1994 (8.1%), 18 in 1995 (16.4%), and 35 in 1996 (27.1%). Epidemiological linkage was confirmed for 68% of cases. This study has demonstrated rapid dissemination of this strain of the Beijing genotype. This genotype might play an important role in the future of the worldwide tuberculosis epidemic.

Adolescent↗
PubMed2001

Ovine Echinococcus granulosus transmission dynamics in the province of Rio Negro, Argentina, 1980-1999.

In this work, the impact of a hydatidosis control programme for dogs on the intermediate ovine host was specifically analysed to determine the levels of prevalence achieved and the dynamics of parasite transmission, as well as to evaluate the quality of diagnostic systems in slaughterhouses. A field study was conducted in four slaughterhouses (Valcheta, Los Menucos, Jacobacci, Bariloche) that process animals coming from all the departments within the work area. The control programme for dogs entailed treating dogs with 5 mg/kg praziquantel at 2-month intervals for 20 years. Sample size was determined with a 10% error margin and a 95% significance level. Harvested viscera (liver, lungs, kidneys) were preserved in 5% formaldehyde and sent to the laboratory for diagnostic confirmation of both positive and negative specimens. The 61% initial prevalence dropped to 18.3% at the end of the 10-year period, observed differences proving significant (Chi-square=15.454, P=0.00). There were statistically significant increases in infection prevalence with age (Pearson's Chi-square=133.61, P=0.00). Overall, 37.2% of hydatidosis cases diagnosed in slaughterhouses were considered non-hydatid by histological study. On the other hand, 1.1% of those diagnosed as healthy were found to be infected with hydatidosis. The number of hydatid cysts per animal increased with age: 0.04 in lambs and 1.22 in adults (linear regression equation, -0.0539+0.0127 x age), whereas the average for the whole period was 3.7% in lambs and 20.5% in adults. Viability studies indicated that 63.8% of parasitised animals had viable cysts, out of which 53.3% were fertile. Diagnosis of infection in sheep made by means of an adjusted statistical design and with histological confirmation of the presumptive diagnosis made in slaughterhouses demonstrated the flaws of the official systems for epidemic surveillance of hydatidosis. However, there was no overall significant difference in slaughterhouse and laboratory data.Ro was 0.53 and could imply a decrease in reproductive capacity of the parasite and steady state extinction.

Abattoirs↗
PubMed2001

Exogenous reinfection with tuberculosis on a European island with a moderate incidence of disease.

The frequency and determinants of exogenous reinfection and of endogenous reactivation of tuberculosis in patients previously treated are poorly understood. In Gran Canaria Island, Spain, between 1991 and 1996, 962 tuberculosis cases were confirmed by culture. Drug susceptibility testing was performed on available bacterial isolates and IS6110-based RFLP genotyping was carried out. Twenty-three patients (2.4%) had two positive cultures separated by at least 12 mo, 18 of whom had bacterial DNA available for genotypic analysis. The initial and final isolates from eight (44%) were different genotypes, indicating exogenous reinfection. Six of them were retreated after cure and two retreated after default. Six were HIV seronegative and two were HIV seropositive. Endogenous reactivation was seen in the remaining 10 patients of whom eight were retreated after default and two after cure. Three of the eight (38%) being retreated after default developed multidrug resistance. One genotype was responsible for a second episode of tuberculosis in five cases, three exogenous reinfections and two endogenous reactivations. In the context of a moderate incidence of tuberculosis, exogenous reinfection is an important cause of TB recurrence, even in HIV-seronegative patients.

Adult↗
PubMed2001

Expression of CD44 splice variants in spontaneous murine tumors.

CD44 is a widely distributed set of cell surface glycoproteins expressed in several types of cells and tissues, implicated in cell-cell and cell-substrate interactions. This molecule plays a major role in cell differentiation, development and activation and has also been described as a potential marker of malignancy and metastasis. In the present study we investigated by RT-PCR followed by exon specific amplification the expression of CD44 splice variants in four different murine tumors as well as in the invaded organs in order to correlate the expression of CD44 variants with potential tumor invasiveness and their implications for growth. Our data showed deregulation in the expression of CD44 isoforms but no discernible correlation in isoform expression pattern. However, in all tumors studied isoforms presented by the primary tumor were detected in the invaded organs before metastasis could be demonstrated by histopathological analysis.

Alternative Splicing↗
PubMed1998

Human cystic echinococcosis in a Uruguayan community: a sonographic, serologic, and epidemiologic study.

A prevalence and transmission study of human cystic echinococcosis (CE), due to infection with the dog tapeworm Echinococcus granulosus, was undertaken in the village of La Paloma in central Uruguay. The human population was registered and screened for CE by abdominal ultrasound scan as well as a number of serologic tests. Dogs were screened for E. granulosus infection by arecoline purgation as well as specific coproantigen testing. The total prevalence of human CE (new cases and those with a previous history) was 5.6% (64 of 1,149); 3.6% (40) of the cases were new ultrasound detected asymptomatic cases (mean age = 45 years). Age prevalence increased from 1.1% in the 4-6-year-old group to > 11% in the > 60-year-old group; the 20-29-year-old group had a significantly higher CE rate of 7.4%, compared with younger and older age groups, and there was no difference between sexes. A CE rate of 3.9% (20 of 514) was also recorded by ultrasound for new cases in the population residing outside the village. Most of the hydatid cysts were located in the liver presenting as either univesicular cysts or a solid mass, and of those 71% and 63%, respectively, with such cyst presentations were seropositive against E. granulosus cyst fluid antigens. Two of eight individuals who were filter paper blood spot seropositive, but ultrasound scan negative, were subsequently diagnosed respectively with pulmonary hydatidosis after radiography, and hepatic hydatidosis after computed tomography scan. Of 36 households with a CE patient, 32 were single cases while four households each harbored two CE cases. This did not represent a clustered distribution within families (23 of 117). Almost 20% of the dogs from La Paloma were found infected with E. granulosus after purge examination, with a mean worm number of 67 (range = 1-1,020). An additional eight dogs that were purge negative were Echinococcus coproantigen positive. The study showed that human CE is highly endemic in Uruguay, with one of the highest local prevalence rates in the world. Transmission appears to occur readily within well-developed towns, as well as on rural sheep ranches. Mass screening by ultrasound scanning with confirmatory serologic testing is an effective approach to case detection at the community level.

Adolescent↗
PubMed1996

Effect of immediate and delayed post preparation on apical dye leakage using two different sealers.

Eighty freshly extracted teeth were endodontically prepared and filled with gutta-percha and either a zinc oxide-eugenol-based sealer or AH26 to determine what effect these sealers, with widely differing properties, would have on apical microleakage after either immediate or delayed dowel space preparation. The teeth were randomly assigned to 1 of 4 groups, and the post space was made either immediately after filling or after being stored in 100% humidity for 1 wk. They were then immersed in a 2% methylene blue solution under vacuum, washed, and split longitudinally. The extent of dye penetration was read by five independent observers and the results analyzed. The only significant difference was in the delayed preparation group with zinc oxide-eugenol sealer, which showed greater leakage than the other groups.

Analysis of Variance↗
PubMed1996

Evaluation of a directly observed six months fully intermittent treatment regimen for tuberculosis in patients suspected of poor compliance.

BACKGROUND: Although a priority for tuberculosis control is to achieve the maximum cure rate, compliance with chemotherapy in specific high risk groups (homeless, intravenous drug abusers, chronic alcoholics) is usually poor. METHODS: From January 1990 to December 1994 102 patients with tuberculosis (96 pulmonary, six extrapulmonary) who were poorly compliant with treatment were treated with a six month fully intermittent (twice weekly) directly observed regimen. They comprised 71 homeless subjects, 50 chronic alcoholics, 23 intravenous drug abusers, nine infected with HIV, and 11 who had previously abandoned a daily antituberculosis regimen; 53 had more than one of these risk factors. Treatment included isoniazid and rifampicin for six months and pyrazinamide during the first two months. Patients who failed to take their medication on two consecutive occasions were actively sought by telephone or by personal search. RESULTS: After two months of treatment 95 of the 102 patients had taken their medication regularly and 90 of them had negative cultures. Four of the remaining patients had negative cultures after three months. At the end of the six months 87 patients had completed treatment and were considered cured. Only 15 patients abandoned the treatment (13 of whom had more than one risk factor). Only three relapses occurred in the 102 patients at one year follow up and in the 88 patients followed for two years. Two patients required a change of treatment due to major side effects. Although intravenous drug abuse was the only predictor of non-compliance in the multivariate analysis, if the available variables in the second month of treatment were analysed, current poor compliance and abandonment of treatment in the past were found to be significantly associated with non-compliance. CONCLUSIONS: This study shows the efficacy of this intermittent regimen and the effectiveness of a directly observed treatment programme.

Adolescent↗
PubMed1996

Massive hemoptysis as a manifestation of fistulized thoracic aortic aneurysms into the bronchial tree.

Aortobronchial fistulas are an uncommon and serious cause of hemoptysis. We present three cases of aortobronchial fistulas that were diagnosed and treated at our hospital. They were presented as massive hemoptysis. The clinical suspicion of a leaking thoracic aortic aneurysm into the bronchial tree should prompt the correct diagnostic procedures since early surgery is the only way to manage this condition.

Aged↗
PubMed1995

Echinococcus granulosus infections of dogs in the Durazno region of Uruguay.

The prevalence and distribution of Echinococcus granulosus in domestic dogs was examined in three dog populations in the Durazno region of Uruguay. The prevalence was 19.7 per cent in 704 dogs successfully purged with arecoline hydrobromide. Higher prevalences were detected in dogs from the rural area (30.0 per cent) and the village of La Paloma (25.9 per cent) than in the town of Sarandi del Yi (7.9 per cent). The frequency distribution of E granulosus was overdispersed (k, the negative binomial parameter = 0.08), with only a few animals harbouring heavy infections. The results of a questionnaire showed that the prevalence was greatest in male dogs, in dogs that were not kennelled, in dogs that had access to fields and in dogs that were not dosed with praziquantel. Dogs that were given raw sheep offal by their owners were no more likely to be parasitised than other dogs; this may reflect the inaccuracy of the owners' replies, or that the dogs were being infected outside their home.

Animals↗
PubMed1995

Diagnosis of canine echinococcosis: comparison of coproantigen and serum antibody tests with arecoline purgation in Uruguay.

Echinococcus granulosus is one of the most important and widespread of the helminth zoonoses. Diagnosis of E. granulosus infection in dogs currently relies on arecoline dosing and detailed examination of the purge for adult worms. Two immunodiagnostic tests (ELISA) based on genus specific coproantigen detection or serum antibody (IgG, IgA and IgE) detection were compared against arecoline purgation for the detection of Echinococcus in naturally infected dogs in Uruguay. The coproantigen ELISA had a sensitivity of 76.9% compared with 34.6% for the serum IgG ELISA when assessed against 26 purge positive dogs (purge worm count range 1-4331). Coproantigen reactivity was positively correlated (r = 0.65) to purge worm count, with a threshold at over 20 worms. There was no positive correlation of antibody levels with worm counts. In 26 matched Echinococcus positive dog samples, the overall sensitivity of serological detection increased to 69.2% when seroreactivity for IgA and IgE antibodies were included and to 96.2% for both coproantigen and antibody assays combined. The detection of current infection of individual dogs with E. granulosus by coproantigen ELISA has the potential to replace arecoline purgation, while specific serum antibody detection should be useful in assessing Echinococcus exposure in dog populations.

Animals↗
PubMed1995

The epidemiology of tuberculosis in Gran Canaria, Canary Islands, 1988-92: effectiveness of control measures.

SETTING: Since there is no national programme for tuberculosis control in Spain and the epidemiological situation in this country is unknown, a programme against tuberculosis in Gran Canaria (Canary Islands) was started in 1987. OBJECTIVE: To analyze the impact of this control programme, particularly the trend of new cases of tuberculosis by age groups and risk factors for 1988-92. DESIGN: A detailed search of all new cases of tuberculosis was carried out by examining the files of all public and private hospitals and outpatient clinics of the island, the records of the Services of Clinical Microbiology and Pathology of the public hospitals, and the registers of patients with AIDS. RESULTS: The annual rates of new cases of tuberculosis per 100,000 were 32.2 in 1988 (214 cases), 26.2 in 1990 (174 cases), and 29.4 in 1992 (196 cases), and the rates of sputum-positive cases 13.3 (89 cases), 12 (80 cases) and 15 (100 cases), respectively. The distribution of tuberculosis cases by age peaked in the age groups 40-49 and 30-39 years. Between 1988 and 1992, statistically significant differences were found in the percentage of cured patients (21% [45/214] vs 85.7% [168/196]), patients with a delay in diagnosis > 3 months (40.2% [86/214] vs 21.9% [43/196]), and contacts evaluated (45.3% [97/214] vs 90.3% [177/196]). However, an upward trend in the incidence of tuberculosis for 1990-92 was found in association with an increase of new cases among the homeless, immigrants, and HIV-infected people. When these three population groups were excluded from the analysis, the annual rate for the total population showed a progressive decline from 1988-92. CONCLUSIONS: The data studied here show that successful priority control measures (cure rate, early diagnosis, study of contacts) have been achieved in this island. It is necessary, however, to develop strategies for combating the tuberculosis problem in specific high risk populations.

Adolescent↗
PubMed1995

Transbronchial fine needle aspiration in clinical practice.

We review our experience of transbronchial fine needle aspiration (TBFNA) over a 3-year period. A total of 112 TBFNAs were performed on 95 patients. Four aspirates were from peripheral lung lesions, 20 from non-ulcerated submucosal infiltrative lesions, 19 from mediastinal abnormalities close to the tracheobronchial tree, and the remaining 69 were for staging of bronchogenic carcinoma with apparent mediastinal lymph node spread, evaluated by chest computed tomography (CT). In the 20 submucosal lesions TBFNA reached a sensitivity of 82.3%, providing the only evidence of a malignant process in five cases. With respect to the 19 mediastinal lesions arising in close proximity to the central airways, TBFNA permitted a diagnosis in cases that would otherwise have required more invasive procedures, although the diagnostic sensitivity of the technique in this group of patients was poor (26%). In the mediastinal staging group, the sensitivity was 76.9%, with no false positive results. Complete sensitivity of TBFNA for the detection of disease was 65.8%. We conclude that TBFNA is a reliable and low risk procedure.

Adolescent↗
PubMed1995

DNA analysis of bronchoalveolar lavage in the diagnosis of pulmonary lymphoma.

Lung lymphomas frequently present a diagnostic challenge. The diagnosis of malignant lymphoma is possible when lymphocyte subpopulations show aneuploidy or a definable monoclonal surface marker or both. We present a case of lymphoma of the lung in which DNA analysis of bronchoalveolar lavage fluid was the first successful method in the time course of diagnosis.

Aged↗
PubMed1994

Value of DNA analysis in addition to cytological testing in the diagnosis of malignant pleural effusions.

BACKGROUND: Aneuploidy appears to be a highly specific marker for cancer, and measurement of cellular DNA content by flow cytometry is rapid and reliable. This study was undertaken to determine if the addition of DNA analysis improved the sensitivity of cytological diagnosis of malignancy in pleural fluid. METHODS: Pleural effusions from 92 patients were studied by cytological examination and flow cytometry. RESULTS: In 41 patients the final diagnosis was malignancy, there were 40 cases of benign effusions including 22 with pleural tuberculosis, and in the remaining 11 patients with biopsy proven cancer the presence of malignant cells was not found by cytological and histological means in the pleural fluid. Aneuploidy and cytological malignancy were found in 14 samples. There were seven cases with abnormal flow cytometry and negative cytological results. In 12 patients the cytological test results were positive but DNA analysis was normal. Thirty six samples of fluid were both diploid and cytologically negative. Of the 22 tuberculous effusions seven contained aneuploid cells. The sensitivity of DNA and cytological analysis was 51.2% and 63.4%, respectively. The specificity of DNA analysis was 74.5%. CONCLUSIONS: DNA analysis of cells in malignant pleural effusions is both less sensitive and specific than the cytological diagnosis. Flow cytometric analysis is not recommended for routine use in the diagnosis of pleural effusions.

Adolescent↗
PubMed1994

Value of ELISA using A60 antigen in the serodiagnosis of tuberculosis.

This study was set in a general, university hospital in the Canary Islands, with the objective to evaluate an enzyme-linked immunosorbent assay (ELISA) using A60 in the serodiagnosis of tuberculosis. IgG antibody to A60 was determined in 205 patients with active disease [149 culture-positive patients with pulmonary tuberculosis (positive sputum smear 94, negative sputum smear 55) and 56 patients with extrapulmonary tuberculosis], 20 patients with inactive disease, 22 patients with lepromatous leprosy, and 51 controls. The mean levels of anti-A60 antibodies were significantly higher in patients with active disease as compared with controls or patients with inactive disease. Differences were also found between tuberculous patients with pulmonary and extrapulmonary disease. In patients with pulmonary disease, significant differences were detected between smear-positive and smear-negative patients. The overall sensitivity of the test (cutoff 240 ELISA units) was 52.2%. The highest sensitivity was found among smear-positive patients with pulmonary tuberculosis (67%) and the lowest among those with extrapulmonary tuberculosis (32.1%). We conclude that ELISA for the measurement of IgG antibody to Mycobacterium tuberculosis antigen A60 could be of interest, specially in smear-negative cases and extrapulmonary tuberculosis.

Adult↗
PubMed1993

Serum antibodies in canine echinococcosis.

Specific IgG, IgA and IgE antibodies against E. granulosus protoscolex antigen were detected by enzyme-linked immunosorbent assay (ELISA) in sera from dogs experimentally or naturally infected with E. granulosus. The specificities of the IgG, IgA and IgE ELISAs were 100, 100 and 97.3%, respectively. Sera from 626 dogs of different categories and geographic regions in Australia, Uruguay and Kenya were tested. There were distinct differences in antibody responses in experimentally infected canids and in the number of naturally infected dogs found seropositive, depending on geographic region. The overall sensitivities of the ELISA (IgG, IgA and IgE) ranged between 73 and 84%, except for one geographic region where it was 54%. Genetic differences of the dogs and/or antigenic variations of the parasite appear to be responsible for the variations in specific antibody levels in infected dogs. In average, approximately one third of dogs from hyperendemic hydatid regions, without E. granulosus worms at autopsy or negative for E. granulosus infection by arecoline testing, were seropositive for anti-E. granulosus antibodies, suggesting previous infection with or exposure to the parasite. The results of this study demonstrate that, although the diagnosis of current intestinal E. granulosus infection on an individual dog basis is not always reliable by serology, serum antibody ELISA is useful as an epidemiological/educational tool for seroprevalence studies on canine echinococcosis.

Animals↗
PubMed1993

Diagnosis of pleural tuberculosis by detection of specific IgG anti-antigen 60 in serum and pleural fluid.

The objective of this study was the prospective evaluation of the IgG antibody levels to mycobacterial antigen 60 (A60) in serum and pleural fluid and their role in the diagnosis of tuberculous pleuritis. The level of IgG was measured by Elisa in 30 patients with tuberculous pleuritis and 48 control subjects with pleural effusion (24 with carcinoma, 10 with transudative pleural effusion, 11 with empyema or parapneumonic effusion, 1 with pulmonary embolism and 2 due to systemic lupus erythematosus). The median titers of IgG against A60 of both serum and pleural fluid from tuberculous patients [445.6 +/- 133.56 and 263 +/- 72.58 Elisa units (EU) respectively] were significantly higher than those of corresponding median values (97.3 +/- 8.35 and 41.3 +/- 4.93 EU) of the control group (p < 0.01 and p < 0.01, respectively). Considering 240 units as cutoff point for a positive test in serum, the sensitivity was 53.3% and the specificity 100%. In the pleural fluid the cutoff point value was established at 150 units, with a sensitivity of 50% and specificity of 100%. We concluded that Elisa using A60 is a reliable and rapid test with an acceptable sensitivity and magnificent specificity.

Antibodies, Bacterial↗