High prevalence of Pneumocystis jirovecii colonization in Brazilian cystic fibrosis patients.

A high rate of Pneumocystis jirovecii colonization was observed in Brazilian cystic fibrosis (CF) patients (13 out of 34; 38.2%) who underwent bronchoscopy between March 2006 and August 2009 at the Hospital de Clinicas de Porto Alegre, Brazil. Bronchoalveolar lavage samples were collected from these patients and studied by nested PCR amplification of the mitochondrial gene coding for the large subunit ribosomal RNA (mtLSUrDNA). The observed rate of colonization was higher than that reported in European populations. Genotypic characterization of the mtLSUrDNA locus revealed a predominance of the polymorphisms 85C/248C (genotype 1) and 85T/248C (genotype 3), with all samples possessing the wild-type genotype of dihydropteroate synthase. These findings suggest that cystic fibrosis patients could be an important reservoir and source of P. jirovecii infection. Further studies are required to elucidate the role of this common fungal colonization in the evolution of CF patients.

pRB expression in esophageal mucosa of individuals at high risk for squamous cell carcinoma of the esophagus.

AIM: To investigate the pRb expression in a large group of patients with history of chronic exposure to the main risk factors for development of squamous cell carcinoma of the esophagus. METHODS: One hundred and seventy asymptomatic individuals at high risk for esophageal squamous cell carcinoma (consumption of more than 80 g of ethanol and 10 cigarettes/d for at least 10 years) underwent upper gastrointestinal endoscopy with biopsies of the esophageal mucosa. As a control group, specimens of esophageal mucosa obtained from 20 healthy subjects were also studied. Immunohistochemical assessment of the tissues was performed using a monoclonal antibody anti-pRB protein. RESULTS: Absence of the pRB staining, indicating loss of RB function, was observed in 33 (19.4%) of the individuals at risk for esophageal cancer, but in none of the healthy controls (P < 0.02). Loss of pRb expression increased in a stepwise fashion according to the severity of the histological findings (P < 0.005): normal mucosa (11/97 or 11.3%), chronic esophagitis (17/60 or 28.3%), low-grade dysplasia (3/10 or 30%), high-grade dysplasia 1/2 or 50%) and squamous cell carcinoma (1/1 or 100%). CONCLUSION: Our findings suggest that abnormal expression of the pRB protein may be implicated in the process of esophageal carcinogenesis. Additional studies are warranted to define the role of the pRB protein as a biomarker for development of esophageal squamous cell carcinoma in individuals at high risk for this malignancy.

Sensitivity and specificity of nested and real-time PCR for the detection of Pneumocystis jiroveci in clinical specimens.

A polymerase chain reaction (PCR)-based test for Pneumocystis jiroveci (formerly Pneumocystis carinii f. sp. hominis) might be an alternative to histologic diagnoses of P. jiroveci pneumonia (PCP). However, previously developed nested PCR methods tend to have low specificities (high false-positive rates). In this study, nested and quantitative real-time PCR methods for the amplification of the P. jiroveci DHPS (dihydropteroate synthase) gene were evaluated in a variety of stored clinical samples from Spain, South Africa, and Brazil. The sensitivities of both assays were high, ranging from 62.5% to 100% depending on the type of specimen. In a subset of 71 microscopically confirmed PCP cases and 70 negative cases, the sensitivities and specificities were 94% and 81% for nested PCR and 94% and 96% for real-time PCR, respectively. Real-time PCR has a statistically significantly better specificity than nested PCR (P = .015) and is likely to generate fewer false positives.

Neutrophil apoptosis: a marker of disease severity in sepsis and sepsis-induced acute respiratory distress syndrome.

INTRODUCTION: Apoptosis of neutrophils (polymorphonuclear neutrophils [PMNs]) may limit inflammatory injury in sepsis and acute respiratory distress syndrome (ARDS), but the relationship between the severity of sepsis and extent of PMN apoptosis and the effect of superimposed ARDS is unknown. The objective of this study was to correlate neutrophil apoptosis with the severity of sepsis and sepsis-induced ARDS. METHODS: A prospective cohort study was conducted in intensive care units of three tertiary hospitals in Porto Alegre, southern Brazil. Fifty-seven patients with sepsis (uncomplicated sepsis, septic shock, and sepsis-induced ARDS) and 64 controls were enrolled. Venous peripheral blood was collected from patients with sepsis within 24 hours of diagnosis. All surgical groups, including controls, had their blood drawn 24 hours after surgery. Control patients on mechanical ventilation had blood collected within 24 hours of initiation of mechanical ventilation. Healthy controls were blood donors. Neutrophils were isolated, and incubated ex vivo, and apoptosis was determined by light microscopy on cytospun preparations. The differences among groups were assessed by analysis of variance with Tukeys. RESULTS: In medical patients, the mean percentage of neutrophil apoptosis (+/- standard error of the mean [SEM]) was lower in sepsis-induced ARDS (28% +/- 3.3%; n = 9) when compared with uncomplicated sepsis (57% +/- 3.2%; n = 8; p < 0.001), mechanical ventilation without infection, sepsis, or ARDS (53% +/- 3.0%; n = 11; p < 0.001) and healthy controls (69% +/- 1.1%; n = 33; p < 0.001) but did not differ from septic shock (38% +/- 3.7%; n = 12; p = 0.13). In surgical patients with sepsis, the percentage of neutrophil apoptosis was lower for all groups when compared with surgical controls (52% +/- 3.6%; n = 11; p < 0.001). CONCLUSION: In medical patients with sepsis, neutrophil apoptosis is inversely proportional to the severity of sepsis and thus may be a marker of the severity of sepsis in this population.

Absence of dihydropteroate synthase mutations in Pneumocystis jirovecii from Brazilian AIDS patients.

Several studies from developed countries have documented the association between trimethoprim-sulfamethoxazole prophylaxis failure and mutations in the Pneumocystis jirovecii gene coding for dihydropteroate synthase (DHPS). DNA was extracted from Giemsa-stained smears of 70 patients with P. jirovecii pneumonia seen in Porto Alegre, Brazil, from 1997 to 2004. Successful PCR amplification of the DHPS locus was obtained in 57 of 70 cases (81.4%), including five cases (8.7%) that had used sulfa prophylaxis. No DHPS gene mutations were seen. These results suggest that DHPS mutations are currently as rare in Brazil as in other developing countries.

Clinical outcomes of eradication of Helicobacter pylori in nonulcer dyspepsia in a population with a high prevalence of infection: results of a 12-month randomized, double blind, placebo-controlled study.

Ninety-one Helicobacter pylori-positive patients with nonulcer dyspepsia were randomized to receive either lansoprazole, amoxicillin, and clarithromycin or lansoprazole and placebo. A validated questionnaire assessed dyspeptic symptoms at baseline and at 3, 6, and 12 months. Endoscopies and biopsies were performed at baseline and at 3 and 12 months. There was an overall trend, although not statistically significant, for a benefit of H. pylori eradication. Of the patients in the antibiotics group, 16 of 46 (35%) had symptomatic improvement, versus 9 of 43 (21%) in the control group (P = 0.164). In a secondary analysis, it was found that of the patients without endoscopic gastric erosions, 15 of 34 (44%) in the antibiotics group and 5 of 33 (15%) of controls had symptomatic improvement (P = 0.015). Helicobacter pylori eradication did not prove to be clinically beneficial, although a tendency to symptomatic benefit was detected. Further studies are necessary to confirm the implications of endoscopic gastric erosions in these patients.

Nuclear chromatin texture in rectal cancer. Relationship to tumor stage.

OBJECTIVE: To characterize, by morphometric and chromatin texture analysis, a series of rectal carcinomas classified according to Dukes staging. STUDY DESIGN: High-resolution imagery of 6,001 nuclei from 51 specimens of rectal carcinoma and 22 specimens of normal rectal tissue was digitally recorded. A set of 93 features descriptive of the spatial and statistical distribution of nuclear chromatin was computed for each nucleus to form a characteristic signature. RESULTS: Rectal carcinomas were significantly different from normal rectum in their digital signature. Eleven karyometric features, such as nuclear area and total optical density, were clearly different between the groups, with significant differences found in analysis of 8 of those features. The most distinctive pattern in lesion signatures in comparison with normal rectal tissue was observed at Dukes' stage D. However, the highest average signature values were seen at Dukes' stage B. The lesion signatures and total optical density observed in cancer specimens deviated markedly from values in the normal group. CONCLUSION: Chromatin texture signature proved to be a useful method of identifying and characterizing nuclear differences between rectal carcinoma and normal rectal tissue.

Nuclear chromatin texture in rectal carcinoma. Prognostic value.

OBJECTIVE: To investigate the prognostic value of nuclear features in rectal carcinoma. STUDY DESIGN: High-resolution imagery of 3,635 nuclei from 51 patients operated on for rectal cancer at various Dukes' stages was digitally recorded. A set of 93 features descriptive of the spatial and statistical distribution of nuclear chromatin was computed for each nucleus to derive a digital signature. Karyometric features were analyzed for correlation with progression of disease and death. RESULTS: Multivariate analysis of main karyometric features in comparison with cancer staging demonstrated that total optical density and clumpness, as well as average nuclear signature, had significant prognostic value in predicting cancer-related death. CONCLUSION: Digital signature seems to have a role as prognostic factor in rectal cancer. The method could be a useful parameter in deciding whether to perform adjuvant therapy in particular subgroups of patients, independently of tumor staging. However, these observations need to be substantiated with additional studies, including larger numbers of patients.