Evaluation of low-colony-number counts of Mycobacterium tuberculosis on solid media as a microbiological marker of cross-contamination.

Low-colony-number counts on solid media are considered characteristic of cross-contamination, although they are normally observed in true-positive cultures from some groups of patients. The aim of this study was to evaluate low-yield growth cultures as a microbiological marker for cross-contamination. We evaluated 106 cultures with <15 colonies from 94 patients, and the proportions of false-positive cultures were 0.9% per sample and 1.1% per patient, which indicates that low-yield growth is not a reliable marker of cross-contamination.

Determination of pulp vitality in vivo with pulse oximetry.

AIM: To evaluate the use of pulse oximetry as a test for pulp vitality, by comparing in the same patient, the levels of oxygen saturation of the index finger and of the maxillary central incisor and canine teeth without clinically detectable pulp inflammation. METHODOLOGY: Seventeen male and female patients aged between 26 and 38 years participated and a total of 32 maxillary central incisor and 32 canine teeth were analysed. Selection criteria required the teeth to have healthy crowns, or with restorations no more than 2 mm in diameter and no clinical and radiographical signs or symptoms of pulp or periapical inflammatory changes. The negative control group consisted of 10 root filled teeth. Measurements were first taken from the index finger of patients. Their teeth were then subjected to a thermal test with refrigerant gas and then to a vitality test with pulse oximetry. Data were analysed by Pearson's and paired t-tests. RESULTS: There were no significant statistical correlations between blood oxygen levels in the index finger and in the teeth of the patient (P > 0.05). There was a statistically significant difference in the oxygen levels between the two tooth groups studied and the index finger (P

IFN-gamma in human Chagas' disease: protection or pathology?

An apparently paradoxical role for IFN-gamma in human Chagas' disease was observed when studying the pattern of cytokine production by peripheral blood mononuclear cells (PBMC) obtained from two groups of chagasic patients after specific stimulation with Trypanosoma cruzi-derived antigens. The groups studied were 1) patients treated with benznidazole during the acute phase of Trypanosoma cruzi infection and 2) chronically infected untreated patients. In the treated group, higher levels of IFN-gamma were produced by PBMC from individuals cured after treatment when compared to non-cured patients. In contrast, in the chronically infected group (not treated) higher levels of IFN-gamma were produced by PBMC from cardiac patients in comparison with asymptomatic (indeterminate) patients. This apparently paradoxical role for IFN-gamma in human Chagas' disease is discussed in terms of the possibility of a temporal difference in IFN-gamma production during the initial stages of the infection (acute phase) in the presence or absence of chemotherapy. The maintenance of an immune response with high levels of IFN-gamma production during the chronic phase of the infection may favor cure or influence the development of the cardiac form of the disease.

Relationship of inflammatory markers and pain in patients with head and neck cancer prior to anticancer therapy.

Pain is a common symptom in patients with cancer, including those with head and neck cancer (HNC). While studies suggest an association between chronic inflammation and pain, levels of inflammatory cytokines, such as C-reactive protein (CRP) and tumor necrosis factor-alpha (TNF-α), have not been correlated with pain in HNC patients who are not currently undergoing anticancer treatment. The purpose of this study was to examine the relationship between these inflammatory markers and perceived pain in HNC patients prior to anticancer therapy. The study group consisted of 127 HNC patients and 9 healthy controls. Pain was assessed using the Brief Pain Inventory (BPI), and serum levels of CRP and TNF-α were determined using the particle-enhanced turbidimetric immunoassay (PETIA) and ELISA techniques, respectively. Patients experiencing pain had significantly higher levels of CRP (P<0.01) and TNF-α (P<0.05) compared with controls and with patients reporting no pain. There were significantly positive associations between pain, CRP level, and tumor stage. This is the first study to report a positive association between perceived pain and CRP in HNC patients at the time of diagnosis. The current findings suggest important associations between pain and inflammatory processes in HNC patients, with potential implications for future treatment strategies.

Relationship of inflammatory markers and pain in patients with head and neck cancer prior to anticancer therapy

Pain is a common symptom in patients with cancer, including those with head and neck cancer (HNC). While studies suggest an association between chronic inflammation and pain, levels of inflammatory cytokines, such as C-reactive protein (CRP) and tumor necrosis factor-alpha (TNF-α), have not been correlated with pain in HNC patients who are not currently undergoing anticancer treatment. The purpose of this study was to examine the relationship between these inflammatory markers and perceived pain in HNC patients prior to anticancer therapy. The study group consisted of 127 HNC patients and 9 healthy controls. Pain was assessed using the Brief Pain Inventory (BPI), and serum levels of CRP and TNF-α were determined using the particle-enhanced turbidimetric immunoassay (PETIA) and ELISA techniques, respectively. Patients experiencing pain had significantly higher levels of CRP (P<0.01) and TNF-α (P<0.05) compared with controls and with patients reporting no pain. There were significantly positive associations between pain, CRP level, and tumor stage. This is the first study to report a positive association between perceived pain and CRP in HNC patients at the time of diagnosis. The current findings suggest important associations between pain and inflammatory processes in HNC patients, with potential implications for future treatment strategies.

Toxocara infection is not associated with viral or bacterial central nervous system infection in children.

BACKGROUND: Helminth infections with larvae that migrate through the tissues have been considered risk factors for CNS infections. OBJECTIVES: The present work was designed to investigate the prevalence of anti- TOXOCARA antibodies in the serum and/or in the cerebrospinal fluid (CSF) of children with infectious meningitis or meningoencephalitis and of a control group, without meningitis, admitted at the Children's Hospital NS Glória, Vitória, ES, Brazil. PATIENTS AND METHODS: After adsorption with ASCARIS LUMBRICOIDES antigen, serum and/or cerebrospinal fluid of 381 inpatients (201 with meningitis and 180 without meningitis) were submitted to an ELISA IgG, for anti- TOXOCARA antibodies using secretion/excretion antigens of third stage larvae of T. CANIS. RESULTS: No significant differences between the meningitis and the control groups were observed in the frequencies of positive tests for anti- TOXOCARA antibodies in the serum or CSF (respectively for the meningitis and control group: 33/103 or 32 % and 52/152 or 34.2 % for the serum, p = 0.821; 48/184 or 26.1 % and 23/121 or 19.0 % for the CSF; p = 0.196. CONCLUSION: The results demonstrated that TOXOCARA infection, evaluated by detection of anti- TOXOCARA antibodies in serum or CSF, is not associated with viral or bacterial meningitis or meningoencephalitis in children in our country.

Comparative study of the presence of Trypanosoma cruzi kDNA, inflammation and denervation in chagasic patients with and without megaesophagus.

Neuronal lesions have been considered the hallmark of chagasic megaesophagus, but the role of Trypanosoma cruzi and the participation of the inflammatory cells in this process are still debated. In the present study we counted neurons in the oesophagus from patients with and without megaesophagus and further examined these samples for the presence of parasite kDNA and cells with cytolytic potential (Natural Killer cells, cytotoxic lymphocytes and macrophages). The presence of parasite kDNA was demonstrated in 100% of cases with megaesophagus and in 60% of patients without megaesophagus. When analysed for the number of neurons, the patients without megaesophagus could be classified into 2 groups, as having normal or a decreased number of neurons. The former group did not show any inflammatory process, but interestingly, all patients without megaesophagus presenting decreased number of neurons also presented both parasite kDNA and inflammatory process in the organ. We further observed that the numbers of cytotoxic cells in the myenteric plexus region inversely correlate with the number of neurons. These data together strongly suggest that chronic lesions in chagasic megaesophagus might be a consequence of immune-mediated mechanisms, that last until the chronic phase of infection, and are dependent on the persistence of parasite in the host's tissue.

Decreased CD4(+) circulating T lymphocytes in patients with gastrointestinal chagas disease.

The gastrointestinal form of Chagas disease is characterized by lumenal enlargement and wall thickening of the esophagus and/or colon. Very little is known about the involvement of the immune system in the development of the gastrointestinal form of the disease. In this paper we describe our initial observations on the phenotypic analysis of peripheral blood mononuclear cells from patients with the gastrointestinal form of Chagas disease. A significant decrease in the absolute number of CD3(+) T cells as well as in CD19(+) B lymphocytes was observed. However, the most striking observation was an inversion of the CD4/CD8 ratio, contrasting with results from cardiac chagasic patients in whom the ratio is normal. A decrease of the percentage of CD4(+)CD28(+) cells and an increase in the expression of HLA-DR both on CD4(+) and on CD8(+) cells suggest that although these T cells express activation markers their function may be altered by the lack of CD28 expression.

Immunological and clinical evaluation of chagasic patients subjected to chemotherapy during the acute phase of Trypanosoma cruzi infection 14-30 years ago.

We recently evaluated the in vitro proliferative response and interferon (IFN)-gamma production of peripheral blood mononuclear cells from a group of 25 people who were treated for Chagas' disease during the acute phase of Trypanosoma cruzi infection and followed up for a period of 14-30 years. On the basis of the parasitological and serological tests, the individuals were classified as cured (C), dissociated, or not cured (NC). Members of group C (the group without cardiac alterations) presented significantly stronger proliferative response against the parasite antigens, with secretion of high levels of IFN-gamma in comparison with the NC group, raising a question about the role of this cytokine in the curing of human T. cruzi infection. Severe cardiac alterations were observed only in 1 of 25 patients, which suggests that treatment benefited the patients.

Phenotypic features of peripheral blood leucocytes during early stages of human infection with Trypanosoma cruzi.

We performed a cross-sectional flow cytometric analysis of peripheral blood mononuclear cells to evaluate human immunologic status during early stages of Trypanosoma cruzi infection in children. We identified major immunological features corresponding to three proposed phases of disease: early acute (EA) phase, late acute (LA) phase and recent chronic (RC) phase. EA phase was accompanied by expansion of conventional B cells, up-regulation of CD54 on monocytes and down-regulation of CD54 on T cells and not associated with monocyte-activation phenotypes or changes of natural killer (NK) population. LA phase was characterized by a selective increase in a distinct lineage of NK cells (CD16+CD56-), as well as a persistent expansion of B cells and down-regulation of CD54 on T cells. RC phase showed persistent low levels of CD54 molecule on T cells and an increase of B cells, mainly triggered by expansion of the B1-cell subset, as well as increased expression of human leucocyte antigen (HLA-DR) by monocytes. These findings reinforce the hypothesis that T. cruzi-derived antigens are able to activate NK cells before the development of T-cell-mediated immunity. Moreover, our data support previous findings of increased levels of B1 lymphocytes during human Chagas' disease and show that this event is already present during initial stages of chronic infection.

IFN-gamma in human Chagas' disease: protection or pathology?

An apparently paradoxical role for IFN-gamma in human Chagas'disease was observed when studying the pattern of cytokine production by peripheral blood mononuclear cells (PBMC) obtained from two groups of chagasic patients after specific stimulation with Trypanosoma cruzi-derived antigens. The groups studied were 1) patients treated with bendnidazole during the acute phase of Trypanosoma cruzi infection and 2) chronically infected untreated patients. In the treated group, higher levels of IFN-gamma were produced by PBMC from individuals cured after treatment when compared to non-cured patients. In contrast, in the chronically infected group (not treated) higher levels of IFN-gamma were produced by PBMC from cardiac patients in comparison with asymptomatic (indeterminate) patients. This apparently paradoxical role for IFN-gamma in human Chagas'disease is discussed in terms of the possibility of a temporal difference in IFN-gamma production during the initial stages of the infection (acute phase) in the presence or absence of chemotherapy. The maintenance of an immune response with high levels of IFN-gamma production during the chronic phase of the infection may favor cure or influence the development of the cardiac form of the disease.