Post-extubation atelectasis in newborns with surgical diseases: a report of two cases involving the use of a high-flow nasal cannula.

Atelectasis is a pulmonary disorder that lengthens the hospitalization time of newborns in intensive care units, resulting in increased morbidity among these infants. High-flow nasal cannulae have been used in newborns to prevent atelectasis and/or expand pulmonary regions affected by atelectasis; however, to date, no evidence-based data regarding this approach have been reported. In this paper, we report on the cases of two male newborn patients. The first and second patients described in this report were hospitalized for a neurosurgical procedure and the treatment of abdominal disease, respectively, and were subjected to invasive mechanical ventilation for 4 and 36 days, respectively. After extubation, these patients continued receiving oxygen therapy but experienced clinical and radiological worsening typical of atelectasis. In both cases, by 24 hours after the implantation of an high-flow nasal cannulae to provide noninvasive support, radiological examinations revealed the complete resolution of atelectasis. In these cases, the use of an high-flow nasal cannulae was effective in reversing atelectasis. Thus, this approach may be utilized as a supplemental noninvasive ventilatory therapy to avoid unnecessary intubation.

Identification of primary drug resistance to rifampin in Mycobacterium leprae strains from leprosy patients in Amazonas State, Brazil.

The aim of this study was to identify polymorphisms in the folp1, gyrA, and rpoB genes in leprosy patients treated in Amazonas State, Brazil. Among 197 slit-skin smear samples from untreated or relapsed patients, we found three cases of primary resistance to rifampin and one confirmed case of multidrug resistance.

Effects of Passiflora nitida Kunth leaf extract on digestive enzymes and high caloric diet in rats.

The present study investigated inhibition of pancreatic lipase and metabolic effects of high caloric diet in rats. The Passiflora nitida hydroethanol leaf extract (PNE) was used in in vitro assays or administered to rats to study dyslipidemia. Inhibition of lipase in vitro was studied by a spectrophotometric assay using orlistat as the positive control. The effects of PNE on reduction of postprandial triglyceride were studied by oral fat-overloading in rats. Metabolic alterations were induced using the cafeteria diet and 4 weeks post-treatment with PNE or orlistat and blood samples were collected and biochemical analyses were performed. Liver and retroperitoneal fat tissues were obtained to analyze weight and steatosis. IC50 (lg/mL) values for pancreatic lipase inhibition were 21.2 ± 0.8 and 0.1 ± 0.01 for PNE and orlistat, respectively. Oral administration of lipid emulsion resulted in postprandial hypertriglyceridemia at 3 h postadministration and when rats were then administered PNE and orlistat there was decreased of triglyceride levels by 15 % compared to control. Although the energy consumption by the cafeteria diet had been higher, there was no significant weight gain observed in the study groups. The cafeteria diet resulted in a significant increase of weight in the retroperitoneal fat and hypertriglyceridemia levels that could be significantly reduced by PNE and orlistat treatment. We hypothesized that PNE administration prevented the hypertriglyceridemia in rats with a high caloric diet, possibly owing to reduction of lipid absorption and pancreatic lipase inhibition.

Dual role of IL-12 in the therapeutic efficacy or failure during combined PEG-Interferon-α2A and ribavirin therapy in patients with chronic hepatitis C.

Several efforts have been made to establish novel biomarkers with relevant predictive values to monitor HCV-infected patients under pegilated Interferon-α2A-(PEG-IFN-α2A)/ribavirin therapy. The aim of this study was to monitor the kinetics of HCV viral load, serum levels of pro-inflammatory/regulatory cytokines and leukocyte activation status before and after PEG-IFN-α2A/ribavirin therapy in 52 volunteers, including 12 chronic HCV patients and 40 controls. The HCV viral load, serum levels of cytokines (IL-8/IL-6/TNF-α/IL-12/IFN-γ/IL-4/IL-10) and the phenotype of peripheral blood leukocytes were evaluated before and after 4, 12 and 24 weeks following the PEG-IFN-α2A/ribavirin therapy. Our results demonstrated that sustained virological response-(SVR) is associated with early decrease in the viral load after 4 weeks of treatment. The presence of a modulated pro-inflammatory profile at baseline favors SVR, whereas a strong inflammatory response at baseline predisposes to therapeutic failure. Furthermore, a time-dependent increase on serum IL-12 levels in patients under treatment is critical to support the SVR, while the early predominance of IL-10 correlates to late virological relapse. On the other hand, a broad but unguided "cytokine storm" is observed in the non-responder HCV patients after 12 weeks of treatment. Corroborating these findings, monocyte/lymphocyte activation at baseline is associated with the non-responders to therapy whereas high CD8(+) T-cell numbers associate with SVR. All in all, these data suggest that the baseline pattern of serum pro-inflammatory/regulatory cytokines and the immunological activation status of chronic HCV patients undergoing PEG-IFN-α2A/ribavirin therapy are closely related with the therapeutic response.

Decreased RNA expression of interleukin 17A in skin of leprosy.

Interleukin-17A (IL-17A) is a proinflamatory cytokine that plays an important role in fighting pathogens at mucosal interfaces, by summoning neutrophils and upregulating cytoplasmatic antimicrobial peptides. So far, the presence of IL-17A in leprosy has not been demonstrated. The expression of IL-17A and related cytokines (IL-6 and IL-23p19) was addressed through RNA extraction and cDNA quantitative amplification in macerated biopsies of active lesions of 48 leprosy patients and 20 fragments of normal skin of individuals. Blood levels of IL-17A, IL-23p19 and IL-6 were determined by ELISA. We found an abrogated mRNA IL-17A response in all biopsies of leprosy patients, as compared with controls. Circulating IL-17A and IL-23p19 were undetectable in both patients and controls, but IL-6 was higher in lepromatous patients. Although at low levels, IL-17A mRNA in lepromatous patients had an inverse linear correlation with bacillary burden. Low expression of IL-17A in patients may be a constitutive genetic feature of leprosy patients or a circumstantial event induced by the local presence of the pathogen, as an escape mechanism.

Mast cells modulate pulmonary acute inflammation and host defense in a murine model of tuberculosis.

BACKGROUND: Mast cells (MCs) participate in host resistance to several pathogens, but little is known about the role played by MCs in Mycobacterium tuberculosis infection. METHODS: Compound 48/80 (C48/80)-treated mice and nontreated mice were infected intratracheally with 1 x 10(5) viable M. tuberculosis bacilli (MTB; strain H37Rv). RESULTS: Infected BALB/c mice developed an acute pulmonary inflammation and had higher levels of tumor necrosis factor- alpha , interleukin-1, keratinocyte-derived chemokine, monocyte chemotactic protein-1, and macrophage inflammatory protein-2 in the lungs by day 15. In vivo degranulation of MCs by C48/80 led to a reduction in the inflammatory reaction that was associated with a marked decline in lung proinflammatory cytokine and chemokine levels. The magnitude of the cellular immune response was also partially impaired in infected mice treated with C48/80. The number of Mycobacteria bacilli recovered from the lungs of infected mice treated with C48/80 was 1 log higher than that recovered from untreated infected mice. C48/80 treatment attenuated the granulomatous inflammation in the lung parenchyma seen in untreated MTB-infected mice. CONCLUSIONS: These findings suggest that MCs participate in host defense against M. tuberculosis infection through the production and secretion of cytokines and chemokines that play a role in the recruitment and activation of inflammatory cells in this experimental model.

Inhibition of leukotriene biosynthesis abrogates the host control of Mycobacterium tuberculosis.

Leukotrienes produced from arachidonic acid by the action of 5-lipoxygenase (5-LO) are classical mediators of inflammatory responses. Recently, it has been demonstrated that leukotrienes also play an important role in host defense against microorganisms. In vitro studies have shown that leukotrienes augmented the anti-mycobacterial activity of neutrophils. In this study, we examined the role of leukotrienes in regulating host response and cytokine generation in a murine model of tuberculosis. Administration of the 5-LO pathway inhibitor MK 886, which reduced lung levels of both the leukotriene B(4) and the anti-inflammatory substance lipoxin A(4) by approximately 50%, increased 60-day mortality from 14% to approximately 57% in Mycobacterium tuberculosis-infected mice, and increased lung bacterial burden by approximately 15-fold. Although MK 886-treated animals exhibited no reduction in pulmonary leukocyte accumulation, they did manifest reduced levels of nitric oxide generation and of the protective type 1 cytokines interleukin-12 and gamma interferon. Together our results demonstrate that 5-LO pathway product(s) - presumably leukotrienes - positively regulate protective Th1 responses against mycobacterial infection in vivo. Moreover, the immunosuppressive phenotype in infected mice observed with MK 886 is most consistent with inhibition of an activator (LTB(4)) rather than a suppressor (LXA(4)) of antimicrobial defense, suggesting the major effect of leukotrienes.

Comparison of different delivery systems of DNA vaccination for the induction of protection against tuberculosis in mice and guinea pigs.

The great challenges for researchers working in the field of vaccinology are optimizing DNA vaccines for use in humans or large animals and creating effective single-dose vaccines using appropriated controlled delivery systems. Plasmid DNA encoding the heat-shock protein 65 (hsp65) (DNAhsp65) has been shown to induce protective and therapeutic immune responses in a murine model of tuberculosis (TB). Despite the success of naked DNAhsp65-based vaccine to protect mice against TB, it requires multiple doses of high amounts of DNA for effective immunization. In order to optimize this DNA vaccine and simplify the vaccination schedule, we coencapsulated DNAhsp65 and the adjuvant trehalose dimycolate (TDM) into biodegradable poly (DL-lactide-co-glycolide) (PLGA) microspheres for a single dose administration. Moreover, a single-shot prime-boost vaccine formulation based on a mixture of two different PLGA microspheres, presenting faster and slower release of, respectively, DNAhsp65 and the recombinant hsp65 protein was also developed. These formulations were tested in mice as well as in guinea pigs by comparison with the efficacy and toxicity induced by the naked DNA preparation or BCG. The single-shot prime-boost formulation clearly presented good efficacy and diminished lung pathology in both mice and guinea pigs.

Histamine modulates mast cell degranulation through an indirect mechanism in a model IgE-mediated reaction.

Histamine is released in inflammatory reactions and exerts an immunoregulatory function on cells present in the microenvironment. In this study, we compared the effect of histamine on degranulation of mast cells derived from animals bearing a parasitic infection with those from uninfected animals. Peritoneal mast cells (PMC) were obtained 24 days after infection of Wistar rats with Toxocara canis. The degree of degranulation was assessed either morphologically or by measuring the release of beta-hexosaminidase and TNF-alpha. Non-purified PMC or mast cells immunomagnetically purified with mAb AA4 were used. An increase in degranulation of non-purified mast cells from infected animals was observed after incubation with histamine in vitro or when histamine was injected into the peritoneal cavity. When a purified mast cell population was used, this effect was no longer observed. Supernatants from spleen cells stimulated with histamine induced degranulation of purified mast cells, and again, this was potentiated with PMC from infected animals. However, when supernatants from peritoneal macrophages similarly stimulated were used, a reduction in the degranulation of PMC from infected animals was observed. Our results suggest that histamine may act as a regulator of mast cell degranulation, thus modulating inflammatory responses due to infection with certain parasites.

Differential modulation of cell recruitment and acute edema in a model of Polybia paulista venom-induced inflammation.

Hymenoptera stings are quite common and can cause inflammatory reactions (in nonallergic individuals) or serious reactions (in allergic individuals). Hymenoptera venom contains histamine, vasoactive kinins, serotonin, phospholipase A, phospholipase B, hyaluronidase, antigen 5 and mastoparans. Some of these substances are responsible for local pain, as well as for activation of complement and endothelial cells. Polybia paulista is a wasp typically found in the state of São Paulo, Brazil. In the present study, we evaluated inflammatory reactions in the peritoneal cavities of rats injected with P. paulista venom (PPV). We evaluated leukocyte recruitment and edema formation at the site of inflammation. After i.p. inoculation with PPV, there was dose-dependent and time-dependent recruitment of neutrophils, eosinophils and mononuclear cells. At 4 to 48 h after stimulus, administration of MK 886, a leukotriene synthesis inhibitor, completely abolished granulocyte recruitment to the peritoneal cavity. Therefore, leukotrienes seem to be the primary mediators of PPV-induced neutrophil and eosinophil recruitment. Inoculation with PPV also induced protein extravasation into the peritoneal cavity. This phenomenon was not inhibited by treatment with MK 886 or indomethacin (a prostaglandin synthesis inhibitor), demonstrating that neither leukotrienes nor prostaglandins are involved in this inflammatory reaction. However, edema formation was significantly inhibited by treatment with pyrilamine, indicating that the histamine H1 receptor plays a critical role in PPV-induced formation of acute edema.