Predictive value of the acid fast smear for detection of Mycobacterium tuberculosis in respiratory specimens in a Reference Center of HIV/Aids in Rio de Janeiro, Brazil

In order to evaluate the predictive value of acid fast bacilii (AFB) smear for the diagnosis of Mycobacterium tuberculosis in respiratory specimens in a setting with a high prevalence of Aids and an unknown prevalence of nontuberculous mycobacteria (NTM), we retrospectively examined specimens cultured for mycobacteria between 1 September 1993 and 30 September 1994 and medical records of patients with positive culture in a General Hospital, Aids reference in Rio de Janeiro, Brazil. Seventy three per cent (1517/2077) of samples were respiratory specimens and mycobacteria were recovered from 20.6% (313/1517) of these. M. tuberculosis was identified in 94.2% (295/313) and NTM in 5.8% (18/313). The yield of positive AFB smear and of positive culture was 6.1% (93/1517) and 20.6% (313/1517), respectively. The positive predictive value (PPV) of AFB for M. tuberculosis was 98.4% in expectorated sputum and 96.4% in bronchoalveolar lavage. Forty four percent (130/295) of specimens with positive culture for M. tuberculosis and 66.7% (12/18) for NTM were from patients HIV positive. The conclusion was that in our study population, the PPV of AFB for M. tuberculosis in respiratory specimens was high and the prevalence of NTM was low despite the high prevalence of HIV positive.

The epidemiology and antigenic characterization of influenza viruses isolated in Curitiba, South Brazil

Several studies conducted all over the world have reported that the influenza virus is associated with great morbidity and mortality rates. In this study, we analyzed the incidence of the influenza virus between 2000 and 2003 in Curitiba. We studied 1621 samples obtained from outpatients and hospitalized patients of both sexes and all ages. The study was conducted at the local primary care health units (outpatients) and at the tertiary care unit (hospitalized) of the General Hospital of the Federal University in the state of Paraná, Brazil. Nasopharyngeal aspirates and, eventually, bronchoalveolar lavage were assayed for the presence of viral antigens, either by indirect immunofluorescence or cell culture. Of the samples studied, 135 (8.3%) were positive for influenza virus, and of those, 103 (76.3%) were positive for type A and 32 (23.7%) for type B. Additionally, positive samples were analyzed by reverse transcription followed by polymerase chain reaction and subtypes H1 and H3 were identified from this group. A high incidence of positive samples was observed mainly in the months with lower temperatures. Furthermore, outpatients showed a higher incidence of influenza viruses than hospitalized patients.

Coxiella burnetii, the agent of Q fever in Brazil: its hidden role in seronegative arthritis and the importance of molecular diagnosis based on the repetitive element IS1111 associated with the transposase gene

Coxiella burnetii is the agent of Q fever , an emergent worldwide zoonosis of wide clinical spectrum. Although C. burnetii infection is typically associated with acute infection, atypical pneumonia and flu-like symptoms, endocarditis, osteoarticular manifestations and severe disease are possible, especially when the patient has a suppressed immune system; however, these severe complications are typically neglected. This study reports the sequencing of the repetitive element IS1111 of the transposase gene of C. burnetii from blood and bronchoalveolar lavage (BAL) samples from a patient with severe pneumonia following methotrexate therapy, resulting in the molecular diagnosis of Q fever in a patient who had been diagnosed with active seronegative polyarthritis two years earlier. To the best of our knowledge, this represents the first documented case of the isolation of C. burnetii DNA from a BAL sample.

Tuberculosis patients co-infected with Mycobacterium bovis and Mycobacterium tuberculosis in an urban area of Brazil

In this cross-sectional study, mycobacteria specimens from 189 tuberculosis (TB) patients living in an urban area in Brazil were characterised from 2008-2010 using phenotypic and molecular speciation methods (pncA gene and oxyR pseudogene analysis). Of these samples, 174 isolates simultaneously grew on Löwenstein-Jensen (LJ) and Stonebrink (SB)-containing media and presented phenotypic and molecular profiles of Mycobacterium tuberculosis, whereas 12 had molecular profiles of M. tuberculosis based on the DNA analysis of formalin-fixed paraffin wax-embedded tissue samples (paraffin blocks). One patient produced two sputum isolates, the first of which simultaneously grew on LJ and SB media and presented phenotypic and molecular profiles of M. tuberculosis, and the second of which only grew on SB media and presented phenotypic profiles of Mycobacterium bovis. One patient provided a bronchial lavage isolate, which simultaneously grew on LJ and SB media and presented phenotypic and molecular profiles of M. tuberculosis, but had molecular profiles of M. bovis from paraffin block DNA analysis, and one sample had molecular profiles of M. tuberculosis and M. bovis identified from two distinct paraffin blocks. Moreover, we found a low prevalence (1.6%) of M. bovis among these isolates, which suggests that local health service procedures likely underestimate its real frequency and that it deserves more attention from public health officials.

Toxocara canis and the allergic process

The protective effect of infectious agents against allergic reactions has been thoroughly investigated. Current studies have demonstrated the ability of some helminths to modulate the immune response of infected hosts. The objective of the present study was to investigate the relationship between Toxocara canis infection and the development of an allergic response in mice immunised with ovalbumin (OVA). We determined the total and differential blood and bronchoalveolar lavage fluid cells using BALB/c mice as a model. To this end, the levels of interleukin (IL)-4, IL-5 and IL-10 and anti-OVA-IgE were measured using an ELISA. The inflammatory process in the lungs was observed using histology slides stained with haematoxylin and eosin. The results showed an increase in the total number of leukocytes and eosinophils in the blood of infected and immunised animals at 18 days after infection. We observed a slight lymphocytic inflammatory infiltrate in the portal space in all infected mice. Anti-OVA-IgE levels were detected in smaller proportions in the plasma of immunised and infected mice compared with mice that were only infected. Therefore, we concluded that T. canis potentiates inflammation in the lungs in response to OVA, although anti-OVA-IgE levels suggest a potential reduction of the inflammatory process through this mechanism.

Peritonite por bário

We report a case of a 49 years-old man who underwent a barium meal examination for an epigastric pain. A perforated gastric ulcer with barium extravasation into peritoneal cavity was seen on X-rays. During an emergency laparotomy, a perforated pyloric ulcer was noted, along with barium contamination in the peritoneal cavity. The ulcer was closed with an omental patch and an extensive peritoneal lavage with saline was performed. During the postoperative period, the patient developed signs of peritonitis and underwent a new laparotomy was at the 9th day showing a subfrenic abscess with a large barium contamination. The patient presented septic shock and multiple organ failure. dying on the 21th day.

Complicated diverticular disease: the changing paradigm for treatment

The term "complicated" diverticulitis is reserved for inflamed diverticular disease complicated by bleeding, abscess, peritonitis, fistula or bowel obstruction. Hemorrhage is best treated by angioembolization (interventional radiology). Treatment of infected diverticulitis has evolved enormously thanks to: 1) laparoscopic colonic resection followed or not (Hartmann's procedure) by restoration of intestinal continuity, 2) simple laparoscopic lavage (for peritonitis +/- resection). Diverticulitis (inflammation) may be treated with antibiotics alone, anti-inflammatory drugs, combined with bed rest and hygienic measures. Diverticular abscesses (Hinchey Grades I, II) may be initially treated by antibiotics alone and/or percutaneous drainage, depending on the size of the abscess. Generalized purulent peritonitis (Hinchey III) may be treated by the classic Hartmann procedure, or exteriorization of the perforation as a stoma, primary resection with or without anastomosis, with or without diversion, and last, simple laparoscopic lavage, usually even without drainage. Feculent peritonitis (Hinchey IV), a traditional indication for Hartmann's procedure, may also benefit from primary resection followed by anastomosis, with or without diversion, and even laparoscopic lavage. Acute obstruction (nearby inflammation, or adhesions, pseudotumoral formation, chronic strictures) and fistula are most often treated by resection, ideally laparoscopic. Minimal invasive therapeutic algorithms that, combined with less strict indications for radical surgery before a definite recurrence pattern is established, has definitely lead to fewer resections and/or stomas, reducing their attendant morbidity and mortality, improved post-interventional quality of life, and less costly therapeutic policies.

Management of stab wounds to the anterior abdominal wall

The meeting of the Publication "Evidence Based Telemedicine - Trauma and Emergency Surgery" (TBE-CiTE), through literature review, selected three recent articles on the treatment of victims stab wounds to the abdominal wall. The first study looked at the role of computed tomography (CT) in the treatment of patients with stab wounds to the abdominal wall. The second examined the use of laparoscopy over serial physical examinations to evaluate patients in need of laparotomy. The third did a review of surgical exploration of the abdominal wound, use of diagnostic peritoneal lavage and CT for the early identification of significant lesions and the best time for intervention. There was consensus to laparotomy in the presence of hemodynamic instability or signs of peritonitis, or evisceration. The wound should be explored under local anesthesia and if there is no injury to the aponeurosis the patient can be discharged. In the presence of penetration into the abdominal cavity, serial abdominal examinations are safe without CT. Laparoscopy is well indicated when there is doubt about any intracavitary lesion, in centers experienced in this method.

Temporary abdominal closure with zipper-mesh device for management of intra-abdominal sepsis

OBJECTIVE: to present our experience with scheduled reoperations in 15 patients with intra-abdominal sepsis. METHODS: we have applied a more effective technique consisting of temporary abdominal closure with a nylon mesh sheet containing a zipper. We performed reoperations in the operating room under general anesthesia at an average interval of 84 hours. The revision consisted of debridement of necrotic material and vigorous lavage of the involved peritoneal area. The mean age of patients was 38.7 years (range, 15 to 72 years); 11 patients were male, and four were female. RESULTS: forty percent of infections were due to necrotizing pancreatitis. Sixty percent were due to perforation of the intestinal viscus secondary to inflammation, vascular occlusion or trauma. We performed a total of 48 reoperations, an average of 3.2 surgeries per patient. The mesh-zipper device was left in place for an average of 13 days. An intestinal ostomy was present adjacent to the zipper in four patients and did not present a problem for patient management. Mortality was 26.6%. No fistulas resulted from this technique. When intra-abdominal disease was under control, the mesh-zipper device was removed, and the fascia was closed in all patients. In three patients, the wound was closed primarily, and in 12 it was allowed to close by secondary intent. Two patients developed hernia; one was incisional and one was in the drain incision. CONCLUSION: the planned reoperation for manual lavage and debridement of the abdomen through a nylon mesh-zipper combination was rapid, simple, and well-tolerated. It permitted effective management of severe septic peritonitis, easy wound care and primary closure of the abdominal wall.

Enhanced mucosal re-epithelialization induced by short chain fatty acids in experimental colitis

The short chain fatty acids (SCFA) are the best nutrients for the colonocytes. Glucose is poorly used as a fuel but may be transformed into SCFA by colonic bacteria. The aim of this study was to investigate the effect of SCFA or glucose on experimental colitis. Colitis was induced in 30 Wistar rats by colonic instillation of 4% acetic acid. Five days later they were randomized to receive twice a day colonic lavage containing saline (controls, N = 10), 10% hypertonic glucose (N = 10) or SCFA (N = 10) until day 8 when they were killed. At autopsy, the colon was removed and weighed and the mucosa was evaluated macro- and microscopically and stripped out for DNA assay. Data are reported as mean ± SD or median [range] as appropriate. All animals lost weight but there was no difference between groups. Colon weight was significantly lower in the SCFA group (3.8 ± 0.5 g) than in the control (5.3 ± 2.1 g) and glucose (5.2 ± 1.3 g) groups (P<0.05). Macroscopically, the severity of inflammation was less in SCFA (grade 2 [1-5]) than in control (grade 9 [4-10]) and glucose-treated (grade 9 [2-10]) animals (P<0.01). Microscopically, ulceration of the mucosa was more severe in the glucose and control groups than in the SCFA group. The DNA content of the mucosa of SCFA-treated animals (8.2 [5.0-20.2] mg/g of tissue) was higher than in glucose-treated (5.1 [4.2-8.5] mg/g of tissue; P<0.01) and control (6.2 [4.5-8.9] mg/g of tissue; P<0.05) animals. We conclude that SCFA may enhance mucosal re-epithelialization in experimental colitis, whereas hypertonic glucose is of no benefit.

Role of immunoglobulin E and mast cells in murine models of asthma

Immunoglobulin E (IgE) and mast cells are believed to play important roles in allergic inflammation. However, their contributions to the pathogenesis of human asthma have not been clearly established. Significant progress has been made recently in our understanding of airway inflammation and airway hyperresponsiveness through studies of murine models of asthma and genetically engineered mice. Some of the studies have provided significant insights into the role of IgE and mast cells in the allergic airway response. In these models mice are immunized systemically with soluble protein antigens and then receive an antigen challenge through the airways. Bronchoalveolar lavage fluid from mice with allergic airway inflammation contains significant amounts of IgE. The IgE can capture the antigen presented to the airways and the immune complexes so formed can augment allergic airway response in a high-affinity IgE receptor (FcepsilonRI)-dependent manner. Previously, there were conflicting reports regarding the role of mast cells in murine models of asthma, based on studies of mast cell-deficient mice. More recent studies have suggested that the extent to which mast cells contribute to murine models of asthma depends on the experimental conditions employed to generate the airway response. This conclusion was further supported by studies using FcepsilonRI-deficient mice. Therefore, IgE-dependent activation of mast cells plays an important role in the development of allergic airway inflammation and airway hyperresponsiveness in mice under specific conditions. The murine models used should be of value for testing inhibitors of IgE or mast cells for the development of therapeutic agents for human asthma.

Differential expression of integrin subunits on adherent and nonadherent mast cells

Mast cell progenitors arise in bone marrow and then migrate to peripheral tissues where they mature. It is presumed that integrin receptors are involved in their migration and homing. In the present study, the expression of various integrin subunits was investigated in three systems of adherent and nonadherent mast cells. Mesentery mast cells, freshly isolated bone marrow-derived mast cells (BMMC) and RBL-2H3 cells grown attached to tissue culture flasks are all adherent mast cells and peritoneal mast cells, and cultured BMMC and RBL-2H3 cells grown in suspension represent nonadherent mast cell populations. Pure populations of mast cells were immunomagnetically isolated from bone marrow, mesentery and peritoneal lavage using the mast cell-specific monoclonal antibody AA4. By immunomicroscopy, we could demonstrate that all of these mast cells expressed alpha4, alpha5, alpha6, ß1 and ß7 integrin subunits. The expression of the alpha4 integrin subunit was 25% higher in freshly isolated mesentery mast cells and BMMC. Consistent with the results obtained by immunomicroscopy, mesentery mast cells expressed 65% more mRNA for the alpha4 integrin subunit than peritoneal mast cells. In vitro studies were also conducted using the rat mast cell line RBL-2H3. RBL-2H3 cells grown attached to the tissue culture flasks or as suspension cultures expressed the same integrin subunits identified in bone marrow, mesenteric and peritoneal mast cells ex vivo. Similarly, the expression of alpha4 integrin was higher in adherent cells. Therefore, alpha4 integrins may play a critical role in the anchorage of mast cells to the extracellular matrix in bone marrow and in peripheral tissues.

Pentoxifylline decreases tumor necrosis factor and interleukin-1 during high tidal volume

Tumor necrosis factor-alpha (TNF-alpha) is one of the most important proinflammatory cytokines which plays a central role in host defense and in the acute inflammatory response related to tissue injury. The major source of TNF-alpha are immune cells such as neutrophils and macrophages. We tested the hypothesis that pentoxifylline, a methylxanthine derivative, down-regulates proinflammatory cytokine expression during acute lung injury in rats. Male Wistar rats weighing 250 to 450 g were anesthetized ip with 50 mg/kg sodium thiopental and randomly divided into three groups: group 1 (N = 7): tidal volume (V T) = 7 ml/kg, respiratory rate (RR) = 50 breaths/min and normal saline infusion; group 2 (N = 7): V T = 42 ml/kg, RR = 9 breaths/min and normal saline infusion; group 3 (N = 7): V T = 42 ml/kg, RR = 9 breaths/min and pentoxifylline infusion. The animals were ventilated with an inspired oxygen fraction of 1.0, a positive end-expiratory pressure of 3 cmH2O, and normal saline or pentoxifylline injected into the left femoral vein. The mRNA of TNF-alpha rapidly increased in the lung tissue within 180 min of ventilation with a higher V T with normal saline infusion. The concentrations of inflammatory mediators were decreased in plasma and bronchoalveolar lavage (BAL) in the presence of higher V T with pentoxifylline infusion (TNF-alpha: plasma, 102.2 ± 90.9 and BAL, 118.2 ± 82.1; IL-1ß: plasma, 45.2 ± 42.7 and BAL, 50.2 ± 34.9, P < 0.05). We conclude that TNF-alpha produced by neutrophil influx may function as an alert signal in host defense to induce production of other inflammatory mediators.

Cytotoxicity of chlorhexidine digluconate to murine macrophages and its effect on hydrogen peroxide and nitric oxide induction

Chlorhexidine, even at low concentrations, is toxic for a variety of eukaryotic cells; however, its effects on host immune cells are not well known. We evaluated in vitro chlorhexidine-induced cytotoxicity and its effects on reactive oxygen/nitrogen intermediate induction by murine peritoneal macrophages. Thioglycollate-induced cells were obtained from Swiss mice by peritoneal lavage with 5 ml of 10 mM phosphate-buffered saline, washed twice and resuspended (10(6) cells/ml) in appropriate medium for each test. Cell preparations contained more than 95% macrophages. The cytotoxicity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay and the presence of hydrogen peroxide (H2O2) and nitric oxide (NO) by the horseradish peroxidase-dependent oxidation of phenol red and Griess reaction, respectively. The midpoint cytotoxicity values for 1- and 24-h exposures were 61.12 ± 2.46 and 21.22 ± 2.44 µg/ml, respectively. Chlorhexidine did not induce synthesis or liberation of reactive oxygen/nitrogen intermediates. When macrophages were treated with various sub-toxic doses for 1 h (1, 5, 10, and 20 µg/ml) and 24 h (0.5, 1, and 5 µg/ml) and stimulated with 200 nM phorbol myristate acetate (PMA) solution, the H2O2 production was not altered; however, the NO production induced by 10 µg/ml lipopolysaccharide (LPS) solution varied from 14.47 ± 1.46 to 22.35 ± 1.94 µmol/l and 13.50 ± 1.42 to 20.44 ± 1.40 µmol/l (N = 5). The results showed that chlorhexidine has no immunostimulating activity and sub-toxic concentrations did not affect the response of macrophages to the soluble stimulus PMA but can interfere with the receptor-dependent stimulus LPS.

Differential effect of plant lectins on mast cells of different origins

Histamine release induced by plant lectins was studied with emphasis on the carbohydrate specificity, external calcium requirement, metal binding sites, and mast cell heterogeneity and on the importance of antibodies bound to the mast cell membrane to the lectin effect. Peritoneal mast cells were obtained by direct lavage of the rat peritoneal cavity and guinea pig intestine and hamster cheek pouch mast cells were obtained by dispersion with collagenase type IA. Histamine release was induced with concanavalin A (Con A), lectins from Canavalia brasiliensis, mannose-specific Cymbosema roseum, Maackia amurensis, Parkia platycephala, Triticum vulgaris (WGA), and demetallized Con A and C. brasiliensis, using 1-300 µg/ml lectin concentrations applied to Wistar rat peritoneal mast cells, peaking on 26.9, 21.0, 29.1, 24.9, 17.2, 10.7, 19.9, and 41.5%, respectively. This effect was inhibited in the absence of extracellular calcium. The lectins were also active on hamster cheek pouch mast cells (except demetallized Con A) and on Rowett nude rat (animal free of immunoglobulins) peritoneal mast cells (except for mannose-specific C. roseum, P. platycephala and WGA). No effect was observed in guinea pig intestine mast cells. Glucose-saturated Con A and C. brasiliensis also released histamine from Wistar rat peritoneal mast cells. These results suggest that histamine release induced by lectins is influenced by the heterogeneity of mast cells and depends on extracellular calcium. The results also suggest that this histamine release might occur by alternative mechanisms, because the usual mechanism of lectins is related to their binding properties to metals from which depend the binding to sugars, which would be their sites to bind to immunoglobulins. In the present study, we show that the histamine release by lectins was also induced by demetallized lectins and by sugar-saturated lectins (which would avoid their binding to other sugars). Additionally, the lectins also released histamine from Rowett nude mast cells that are free of immunoglobulins.