High mortality due to gastrointestinal TB in HIV and non-HIV patients

BACKGROUND: Due to the reported low incidence of gastrointestinal TB, there is a lack of data related to the prognosis, risk factors and frequency of resistant TB in this subgroup of patients.OBJECTIVE: To report the clinical presentation, diagnostic methods, treatment and outcomes in gastrointestinal TB.METHODS: We prospectively studied the demographic, clinical, and paraclinical data of all consecutive gastrointestinal TB inpatients over an 8-year period.RESULTS: We identified gastrointestinal TB in 28 (3.5%) out of 799 inpatients with TB infection. Seven patients (25%) were HIV-positive. Overall mortality was 35.7%, with the combined variable of haemoglobin <12 g/dL and albumin <2.8 g/dL being independently associated with mortality (OR 25.7, 95% CI 1.405-471.1, P = 0.029). No difference in the need for surgery (28.6% vs. 47.6%, P = 0.662), occurrence of septic shock (14.3 vs. 23.8%, P = 1.00) or mortality (14.3% vs. 42.9%, P = 0.364) was found between HIV and non-HIV patients.CONCLUSION: Gastrointestinal TB was rare among TB patients in Hospital Universitario "Dr José E. González" (3.5%), but had a high mortality rate (35.7%). Clinical evolution, drug susceptibility patterns and outcomes were similar in HIV and non-HIV patients. In both groups, the combined haemoglobin and albumin variable on admission was clearly associated with mortality.

Chronic obstructive pulmonary disease case finding in Mexico in an at-risk population

OBJECTIVE

To apply a case-finding strategy in Mexico to identify chronic airway obstruction among individuals with risk factors and/or symptoms compatible with chronic obstructive pulmonary disease (COPD).

MATERIAL AND METHODS

Individuals aged ≥ 40 years with known risk factors and/or symptoms compatible with COPD were referred for an interview and spirometry.

RESULTS

Of 2293 subjects included, 472 (20.6%) had a post-bronchodilator forced expiratory volume in one second/forced vital capacity ratio of <70% (for Global Initiative for Chronic Obstructive Lung Disease [GOLD] Stages II-IV, prevalence was 17.1%). Those with airflow obstruction had smoked more cigarettes for more years than subjects without (19 vs. 13 cigarettes/day, P < 0.001, and 32 vs. 23 years, P < 0.001); they also had a more frequent history of exposure to biomass smoke (23.3% vs. 18.3%, P = 0.002). Females were exposed to biomass smoke for more years (24 vs. 19 years; P < 0.0001) and more hours per day than males (6.2 vs. 5.1; P < 0.001). In multiple logistic regression analysis, increasing age, male sex, ever smoking, pack-years of smoking and years of exposure to biomass smoke were significantly associated with COPD prevalence.

CONCLUSIONS

Airflow obstruction was identified in one in five of Mexican individuals with risk factors and/or COPD symptoms. Exposure to biomass smoke was significantly associated with the presence of airflow obstruction.

[Current panorama in the diagnosis of cutaneous tuberculosis]

Pulmonary and cutaneous tuberculosis are caused by Mycobacterium tuberculosis. According to data from the World Health Organization, there are around 8 million new cases per year.The incidence of cutaneous tuberculosis has risen in parallel with that of pulmonary tuberculosis, and coinfection by M tuberculosis and human immunodeficiency virus is considered to be one of the main causes. Current diagnostic methods for pulmonary and extrapulmonary tuberculosis are far from perfect, leading to a delay in starting appropriate therapy.We present a review of these diagnostic methods and of their use in the cutaneous forms. In conclusion,histopathologic findings and isolation of M tuberculosis in cultures of biopsy material or by polymerase chain reaction are the most useful diagnostic tools in cutaneous tuberculosis.

Critical role of ribavirin for the achievement of early virological response to HCV therapy in HCV/HIV-coinfected patients

The response to hepatitis C virus (HCV) therapy seems to be lower in HCV/HIV-coinfected patients than in HCV-monoinfected individuals. Given that most pivotal trials conducted in coinfected patients have used the combination of pegylated interferon (pegIFN) along with fixed low doses (800 mg/day) of ribavirin (RBV), it is unclear whether HIV itself and/or suboptimal RBV exposure could explain this poorer outcome. Two well-defined end points of early virological response were evaluated in Peginterferon Ribavirina España Coinfección (PRESCO), a multicentre trial in which the combination of pegIFN plus RBV (1000 mg if body weight <75 kg and 1200 mg if >75 kg) was prescribed to coinfected patients. For comparisons, we used unpublished data from early kinetics in two other large trials, one performed in HIV-negative patients [Pegasys International Study Group (PISG)] in which RBV 1000-1200 mg/day was used and another [AIDS Pegasys Ribavirin Coinfection Trial (APRICOT)] in which HIV-positive patients received fixed low RBV doses (800 mg/day). A total of 348 HCV/HIV-coinfected patients from the PRESCO trial were analysed as well as all patients treated with pegIFN plus RBV, who completed 12 weeks of therapy in the comparative studies (435 in PISG and 268 in APRICOT). Negative serum HCV-RNA at week 4 (which has the highest positive predictive value of sustained virological response, SVR) was attained in 33.3%, 31.2% and 13% of treated patients with HCV genotype 1, respectively, in PRESCO, PISG and APRICOT. For HCV genotypes 2/3, responses were 83.7%, 84.2% and 37%, respectively. A decline lower than 2 log(10) at week 12 (which has the highest negative predictive value of SVR) was seen in 25.5%, 19.5% and 37% of HCV genotype-1-infected patients, and in 2.1%, 2.9% and 12% of genotypes-2/3-infected patients, respectively. Prescription of high RBV doses enhances the early virological response to HCV therapy in HCV/HIV-coinfected patients, with results approaching those seen in HCV-monoinfected patients.

Dp71ab/DAPs complex composition changes during the differentiation process in PC12 cells

PC12 cells express different Dp71 isoforms originated from alternative splicing; one of them, Dp71ab lacks exons 71 and 78. To gain insight into the function of Dp71 isoforms we identified dystrophin associated proteins (DAPs) that associate in vivo with Dp71ab during nerve growth factor (NGF) induced differentiation of PC12 cells. DAPs expression was analyzed by RT-PCR, Western blot and indirect immunofluorescence, showing the presence of each mRNA and protein corresponding to alpha-, beta-, gamma-, delta-, and epsilon-sarcoglycans as well as zeta-sarcoglycan mRNA. Western blot analysis also revealed the expression of beta-dystroglycan, alpha1-syntrophin, alpha1-, and beta-dystrobrevins. We have established that Dp71ab forms a complex with beta-dystroglycan, alpha1-syntrophin, beta-dystrobrevin, and alpha-, beta- and gamma-sarcoglycans in undifferentiated PC12 cells. In differentiated PC12 cells, the complex composition changes since Dp71ab associates only with beta-dystroglycan, alpha1-syntrophin, beta-dystrobrevin, and delta-sarcoglycan. Interestingly, neuronal nitric oxide synthase associates with the Dp71ab/DAPs complex during NGF treatment, raising the possibility that Dp71ab may be involved in signal transduction events during neuronal differentiation.

Differential expression and subcellular distribution of dystrophin Dp71 isoforms during differentiation process

Dp71 is the major product of the Duchenne muscular dystrophy gene in the brain. In order to study the function of Dp71 in the nervous system we examined the expression of Dp71 isoforms in PC12 rat pheochromocytoma cell line, a well-established system to study neuronal differentiation. We show by reverse transcriptase-polymerase chain reaction and Western blot assays that PC12 cells express two Dp71 isoforms. One isoform lacks exon 71 and the other isoform lacks exons 71 and 78 (Dp71d and Dp71f isoforms respectively). Nerve growth factor-induced neuronal differentiation of PC12 cells results in differential regulation of the expression and subcellular localization of Dp71 isoforms: a) the amount of Dp71f protein increases nine-fold in total extracts while Dp71d increases up to seven-fold in nuclear extracts; b) Dp71f relocates from the cytoplasm to neuritic processes, being prominent at varicosities and the growth cone; c) Dp71d relocates almost entirely to the nucleus and is detected to a lower extent in the cytoplasm and neuritic processes. Dp71f co-localizes with beta-dystroglycan and synaptophysin while Dp71d co-localizes with beta-dystroglycan in the nucleus. Dp71d accumulates at cell-cell contacts where Dp71f is absent. These results suggest that Dp71d and Dp71f associate with different subcellular complexes and therefore may have distinct functions in PC12 cells.

Molecular cloning and characterization of dystrophin and Dp71, two products of the Duchenne Muscular Dystrophy gene, in zebrafish

Dystrophin, the protein responsible for Duchenne Muscular Dystrophy (DMD), plays a critical role in the maintenance of the muscle membrane integrity. There are several forms of dystrophin derived from the DMD gene by alternative promoter usage. In addition to full-length dystrophin (Dp427), four shorter transcripts have been identified: Dp260, Dp140, Dp116 and Dp71. The functional role played by the different products of the DMD gene is not yet determined. To get insight into the function of dystrophin and related products, we have investigated the presence of dystrophin in zebrafish. This choice takes advantage of large-scale mutagenesis screens in zebrafish, which have led to the identification of several mutants with motility defects. The identification and characterization of the genes affected by these mutations is likely to provide relevant information for the understanding of the molecular mechanisms of muscle development and function. Two cDNA clones encoding the homologues of dystrophin and Dp71 in zebrafish were identified and characterized. Both transcripts exhibit a high degree of sequence homology with the dystrophin and Dp71 proteins described in higher vertebrates. In addition, three alternative spliced transcripts that occur at the C-terminal end of the zebrafish DMD gene have been identified. These transcripts exhibit different patterns of tissue expression. We have also determined the chromosomal localization of dystrophin on the radiation hybrid map of the zebrafish genome. Our results indicate that the dystrophin gene is localized to linkage group one. Altogether, these results give new insights on the physiological role played by dystrophin and related proteins, and provide new tools for the identification of mutated genes associated with muscle defects in zebrafish.

Biochemical and histochemical analysis of 71 kDa dystrophin isoform (Dp71f) in rat brain

Dp71 is a member of the dystrophin family and the most abundant dmd gene product in the brain. In the present study, we focused on a short dystrophin transcript named Dp71f, which is alternatively spliced when exon 78 is absent The topographic localization of this protein in the encephalon has not been properly described yet, nor its cellular or subcellular localization, and even less its functions. Dp71f was found to be a cytoplasmic 70 kDa protein and localized in all encephalon regions studied. Double labeling using specific markers for various cell types confirmed Dp71f distribution in the cytoplasm of all cell types studied. Labeling was more conspicuous near the nucleus and diminished towards the periphery of cells. In some cases, we observed cells that were positive for actin and Dp71f in regions corresponding to lamellipodia-like structures. Dp71f and Dp71d isoforms were differently distributed. Our study is the first specific and unambiguous description of the topography and cellular localization patterns of Dp71f in brain, suggesting that Dp71f is a ubiquitous protein.

Dystrophin and Dp71, two products of the DMD gene, show a different pattern of expression during embryonic development in zebrafish

Dystrophin, the protein defective in Duchenne muscular dystrophy (DMD), plays a critical role in the formation and maintenance of the neuromuscular junction. In addition to dystrophin, activation of internal promoters of the DMD gene leads to the production of several short products. Among these, Dp71, which consists of the C-terminal domain of dystrophin, is the most abundant product of the gene in non-muscle tissues and brain. In this report, we compare the temporal and regional expression patterns of dystrophin and Dp71 at different stages of embryonic development and during retinal differentiation in zebrafish. The Dp71 transcripts are the earliest to be expressed at 9-10 h post-fertilization (hpf) in the axial mesoderm. As development proceeds, intense Dp71 staining is observed in the notochord, the developing brain, the marginal regions of the somites and the eye primordium. At the completion of retinal differentiation, Dp71 is expressed in the ganglion and inner nuclear layers. Transcripts encoding dystrophin have a slightly later onset of expression, 13-14 hpf, and remain restricted to the transverse myosepta through all the developmental stages examined. The complementary patterns of expression of dystrophin and Dp71 suggest that these two proteins exert different functions during embryonic development in zebrafish.

Expression and localization of utrophin in differentiating PC12 cells

To ascertain the role of utrophin in cultured neuronal cells, we investigated its expression and distribution along the NGF-induced differentiation of PC12 cells grown on different substrata. Utrophin mRNA was measured by RT-PCR assay and utrophin protein was quantified by immunoblot analysis. The distribution of utrophin and beta-dystroglycan was analyzed by confocal microscopy. We demonstrate that utrophin protein was increased 4-fold during differentiation of cells grown laminin. Concomitant with this up-regulation, utrophin was enriched at the growth cones in differentiating cells, where it co-localizes with beta-dystroglycan. These data suggest the presence of a utrophin-beta-dystroglycan complex in PC12 cells that participates in the formation and/or stabilization of the growth cone-extracellular matrix adhesion.

[Acute correction of nocturnal hypoxemia and sleep pattern using continuous nasal positive pressure in patients with obstructive sleep apnea syndrome]

In order to find out the effectiveness of the nasal CPAP in the treatment of obstructive sleep apnea (OSA), we studied 30 patients with this diagnosis corroborated by nocturnal polysomnography. The average age was 46.37 +/- 11.58 years, 97% were males and 90% were overweight, with a weight of 101.24 +/- 15.57 Kg. All the patients were evaluated before and after the application of nasal CPAP with a pressure of 12.9 +/- 4.35 cm of H2O with a FIO2 of 21%. The sleep efficiency index improved from 0.62 +/- 0.03 to 0.84 +/- 0.02 (p < 0.0001). The maximum duration of the apneas diminished from 65.5 +/- 6.5 seconds to 19 +/- 3.7 seconds (p < 0.0001), and the minimum level of O2 saturation of the hemoglobin increased from 56.8 +/- 3.2% to 84.9 +/- 1.9% (p < 00.0001). These findings showed a clear improvement in the majority of the evaluated parameters in all of the patients, and, in many of them, a normalization. We conclude that the nasal CPAP is effective for the acute improvement of the disorders observed during the sleep in patients with OSA, which supports its therapeutic use in this illness.

Increases in chromosome aberrations and in abnormal sperm morphology in rubber factory workers

Subjects working at a rubber plant in a chemicals warehouse or in calandering and bambury units were analyzed for both sperm parameters and structural chromosome aberrations in peripheral blood lymphocytes. Sperm analysis was performed in a group of 24 workers for comparison with fertile (n = 24) and infertile (n = 24) control groups. The statistical analyses of semen volume, vitality and sperm count did not show significant differences between exposed and fertile groups but significant differences were found from the infertile group. A significantly lower proportion of normal sperm head shapes was found in exposed subjects when compared to the fertile group (40.1 vs. 57.8). Seven exposed workers were re-analyzed 1 year later and their sperm parameters did not change. The cytogenetic analysis showed a significant increase (3.90%) in the percentage of cells with aberrations in bambury workers (n = 11). However, no differences were found between calandering workers (n = 8) and control subjects (n = 10). Workplace air samples taken on the day of tissue sampling did not show any increase above the Cuban maximal allowed concentration for benzo[a]pyrene or toluene.