Retinoic acids up-regulate functional eosinophil-driving receptor CCR3.

Eotaxins and their receptor CCR3 have a definitive role for tissue accumulation of eosinophils both under homeostatic and pathologic conditions. However, physiological stimuli that can up-regulate CCR3 in blood-derived human eosinophils have not been recognized. As a prior gene microarray study revealed up-regulation of CCR3 in eosinophils stimulated with retinoic acids (RAs), the expression of functional CCR3 was examined. We found that 9-cis RA and all-trans RA (ATRA) significantly induced surface CCR3 expression regardless of the presence of IL-3 or IL-5. Pharmacological manipulations with receptor-specific agonists and antagonists indicated that retinoic acid receptor-α activation is critical for CCR3 up-regulation. RA-induced CCR3 was associated with its functional capacity, in terms of the calcium mobilization and chemotactic response to eotaxin-1 (CCL11). Our study suggests an important role of vitamin A derivatives in the tissue accumulation of eosinophils.

Ex vivo application of carbon monoxide in UW solution prevents transplant-induced renal ischemia/reperfusion injury in pigs.

I/R injury is a major deleterious factor of successful kidney transplantation (KTx). Carbon monoxide (CO) is an endogenous gaseous regulatory molecule, and exogenously delivered CO in low concentrations provides potent cytoprotection. This study evaluated efficacies of CO exposure to excised kidney grafts to inhibit I/R injury in the pig KTx model. Porcine kidneys were stored for 48 h in control UW or UW supplemented with CO (CO-UW) and autotransplanted in a 14-day follow-up study. In the control UW group, animal survival was 80% (4/5) with peak serum creatinine levels of 12.0 +/- 5.1 mg/dL. CO-UW showed potent protection, and peak creatinine levels were reduced to 6.9 +/- 1.4 mg/dL with 100% (5/5) survival without any noticeable adverse event or abnormal COHb value. Control grafts at 14 days showed significant tubular damages, focal fibrotic changes and numerous infiltrates. The CO-UW group showed significantly less severe histopathological changes with less TGF-beta and p-Smad3 expression. Grafts in CO-UW also showed significantly lower early mRNA levels for proinflammatory cytokines and less lipid peroxidation. CO in UW provides significant protection against renal I/R injury in the porcine KTx model. Ex vivo exposure of kidney grafts to CO during cold storage may therefore be a safe strategy to reduce I/R injury.

Clinical evaluation after a notification policy of linezolid use: a case series of 22 patients.

Linezolid exhibits a broad spectrum of activity against Gram-positive cocci, including Methicillin-resistant Staphylococcus aureus (mRSA) and vancomycin-resistant enterococci (VRe). However, recent studies have already reported the emergence of linezolid-resistant mRSA or VRe. the purpose of this study is to evaluate not only the efficacy of linezolid for the treatment of nosocomial mRSA infections but also the effect of a notification policy of linezolid use. the charts of inpatients who had been treated with linezolid were reviewed for clinical outcome. After introduction of the notification policy of linezolid use, the clinical success rate was 73.3%, and the rate of appropriate linezolid use was 80%, whereas the success rate was 14.2% and the appropriate use rate was 14.3% before the policy. in conclusion, appropriate use controlled by a notification policy of antibiotics use is essential for prevention of the emergence and spread of linezolid-resistant bacteria, and for proper demonstration of its antibacterial ability.

Thioredoxin reduces C-C chemokine-induced chemotaxis of human eosinophils.

BACKGROUND: Human thioredoxin (TRX) is one of redox-active proteins that regulate reactive oxidative metabolisms. In recent study, we found that serum levels of TRX were elevated in asthmatic patients with exacerbation; however, few details are known about the physiological role of TRX in allergic inflammation, involving eosinophil infiltration. OBJECTIVE: In the present study, we examined whether TRX modulated C-C chemokine-induced chemotaxis of human eosinophils. METHODS: Eosinophils were isolated from subjects with mild eosinophilia by modified CD16 negative selection. After incubation with or without recombinant TRX, chemotaxis of human eosinophils was measured using Boyden chamber. RESULTS: Preincubation with TRX suppressed eotaxin- and regulated on activation, normal T-cell expressed and secreted (RANTES)-induced chemotaxis of eosinophils. Although, TRX had no effect on the expression of C-C chemokine receptor 3, which is a receptor of eotaxin and RANTES, we demonstrated that the activation of extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinases, which play an important role in eosinophil migration, was attenuated by the treatment with TRX. CONCLUSION: Our results suggest that the elicited TRX is beneficial to reduce allergic inflammation through negative regulation of eosinophil functions and has potential in the treatment of allergic diseases, such as asthma.

Soluble vascular cell adhesion molecule-1 induces human eosinophil migration.

BACKGROUND: Tissue eosinophilia is one of the hallmarks of allergic diseases and Th2-type immune responses including asthma. Adhesion molecules are known to play an important role in the accumulation of eosinophils in allergic inflammatory foci, and they contribute to eosinophil activation. Elevated levels of the soluble forms of adhesion molecules in the body fluid of asthmatic patients have been observed, although their pathophysiological significance remains to be fully elucidated. METHODS: Peripheral blood eosinophils were purified, and the effect of soluble vascular cell adhesion molecule-1 (sVCAM-1) on eosinophil migration was investigated using in vitro systems. RESULTS: We found that sVCAM-1 (1 to 10 mug/ml) induced eosinophil chemotaxis, rather than chemokinesis, in a concentration-dependent fashion. In addition, sVCAM-1 induced cell shape change and actin polymerization, which are necessary for cell movement. Manipulations with very late antigen (VLA)-4-neutralizing antibody and signal inhibitors indicated that the sVCAM-1-induced chemotaxis was mediated through ligand-dependent activation of tyrosine kinase Src, p38 mitogen-activated protein kinase (MAPK), and extracellular signal-regulated kinase (ERK) MAPK. Rapid phosphorylation of these signaling molecules was observed using a bead-based multiplex assay. CONCLUSION: Our results raise the possibility of sVCAM-1 in the fluid phase as a significant contributor to the heightened eosinophilic inflammatory response.

Hepatocyte growth factor attenuates eotaxin and PGD2-induced chemotaxis of human eosinophils.

BACKGROUND: Hepatocyte growth factor (HGF) is known to influence a number of cell types, and regulate various biologic activities including cell migration, proliferation, and survival. In a recent study, we found that, in vivo, HGF suppresses allergic airway inflammation, i.e. the infiltration of inflammatory cells including eosinophils into the airway, and further, that HGF reduces Th2 cytokine levels; however, the directly physiologic role of HGF with eosinophils remains unclear. In this study, we investigate the potential of recombinant HGF to regulate the factor-induced chemotaxis of human eosinophils. METHODS: Eosinophils were isolated from subjects with mild eosinophilia by modified CD16-negative selection. After culture with or without recombinant HGF, esoinophil chemotaxis was measured by Boyden chamber and KK chamber. RESULTS: Treatment with HGF prevented eotaxin or prostaglandin D(2) (PGD(2))-induced chemotaxis of eosinophils. Moreover, we demonstrated that extracellular signal-regulated kinase (ERK) 1/2 and p38 mitogen-activated protein kinases as well as the enhancement of Ca(2+) influx, which are indispensable for eosinophil chemotaxis, were attenuated by HGF treatment. CONCLUSION: Taken together, these data suggest that in allergic diseases, HGF not only mediates eosinophils through the inhibition of Th2 cytokines, but also regulates the function of eosinophils directly, provides further insight into the cellular and molecular pathogenesis of allergic reactions.

A population-based study of drug resistance and transmission of tuberculosis in an urban community.

SETTING: A low-income neighborhood of Sao Paulo, Brazil. OBJECTIVE: To determine the incidence, risk factors and transmission patterns of multidrug-resistant tuberculosis (MDR-TB). DESIGN: Prospective longitudinal study of patients with pulmonary TB (PTB). METHODS: Sputum culture-confirmed patients with PTB were recruited between March 2000 and May 2002. Bivariate and multivariate logistic regression analyses were performed to identify factors associated with MDR-TB. Mycobacterium tuberculosis isolates were tested for drug susceptibility and typed by IS6110-RFLP analysis. RESULTS: Of 420 patients, respectively 71% and 27% were new and previously treated; 15.5% of the patients' M. tuberculosis isolates were resistant to at least one drug; of these, 11% and 27% were found among new and previously treated cases, respectively. Respectively 1% and 16.7% of the new and previously treated cases were MDR-TB. RFLP analysis showed that new transmission of MDR strains was uncommon. By multivariate logistic regression analysis, previous TB and hospitalization in the 24 months before TB diagnosis were identified as independent predictors of MDR-TB. CONCLUSIONS: The results showed an intermediate level of MDR-TB incidence in a neighborhood of Sao Paulo and identified predictors that can be targeted for intervention by national and local TB control programs.

Red blood cells regulate eosinophil chemotaxis by scavenging RANTES secreted from endothelial cells.

BACKGROUND: Eosinophils play a critical role in the pathogenesis of allergic diseases. CC chemokines, such as regulated on activation, normal, T cell expressed, and secreted (RANTES), are key regulators of eosinophil locomotion. Although eosinophils migrate from the bloodstream into tissues, mechanisms that generate a chemogradient across the endothelium remain to be fully elucidated. OBJECTIVE: We first examined the polar secretion of RANTES by endothelial cells. We also studied the functional scavenging effect of red blood cells (RBCs) on RANTES secreted into the intravascular side. METHODS AND RESULTS: Endothelial cells were cultured in a transwell chamber with a membrane pore size of 0.45, 3.0, and 8.0 microm and stimulated with TNF-alpha, IL-1beta, or IFN-gamma from the apical or basolateral side for 16 h. The measurement of RANTES in the supernatant was performed by ELISA. We did not see any difference in the amount of RANTES secreted from the cytokine-stimulated endothelium between inner (intravascular side) and outer (extravascular side) wells separated by the 8.0-microm membrane, although apical polarization was observed with the 0.45-microm membrane. The addition of RBCs (hemoglobin (Hb): 0.5-15 g/dL) to the apical supernatant of TNF-alpha-stimulated endothelial cells reduced the RANTES level in a concentration-dependent manner. The treatment of supernatant on the intravascular side with RBCs significantly enhanced the migration of eosinophils. CONCLUSION: RBCs possess a scavenging effect on intravascular RANTES, and thereby regulate transendothelial migration of eosinophils. Our findings suggest a new role of RBCs in allergic inflammation.

Mycobacteraemia among HIV-1-infected patients in São Paulo, Brazil: 1995 to 1998.

From July 1995 to August 1998, mycobacterial blood cultures were obtained from 1032 HIV-infected patients seen at the Centro de Referência e Treinamento de AIDS (CRTA), Hospital São Paulo (HSP), and Centro de Referência de AIDS de Santos (CRAS). Overall, 179 episodes of mycobacteraemia were detected: 111 (62.0%) at CRTA, 50 (27.9%) at HSP, and 18 (10.1%) at CRAS. The frequency of positive cultures declined sharply from 22.6% in 1995 to 6.9% in 1998, consistent with the decrease in opportunistic infections following the publicly funded distribution of highly active antiretroviral therapy. In 1995, mycobacteraemia was more frequently due to Mycobacterium avium complex (59.2%) than Mycobacterium tuberculosis (28.6%), whereas in 1998 the relative frequencies were reversed (28.6 vs. 64.3% respectively), probably justified by the increased virulence of M. tuberculosis and the greater risk of invasive infection in less-immunocompromised patients, including patients unaware they are infected with HIV.

RNA commutes to work: regulation of plant gene expression by systemically transported RNA molecules.

Although long-distance movement of endogenous mRNAs in plants is well established, the functional contributions of these transported RNA molecules has remained unclear. In a recent report, Kim et al.2001 showed that systemically transported mRNA is capable of causing phenotypic change in developing tissue. Here, this finding and its significance are reviewed and discussed in detail. In addition, in order to give proper perspective, long-distance transport of other types of RNAs, e.g., RNA elicitors of post-transcriptional gene silencing and RNA genomes of plant viruses, and its possible regulation are discussed.

Inhibition of systemic onset of post-transcriptional gene silencing by non-toxic concentrations of cadmium.

Post-transcriptional gene silencing (PTGS) is an important mechanism for regulation of plant gene expression and virus-plant interactions. To better understand this process, the heavy metal cadmium was identified as a specific inhibitor in two different PTGS systems, constitutive and inducible. The pattern of cadmium-induced inhibition of PTGS allowed several insights into PTGS development. First, cadmium treatment prevented only systemic but not local onset of PTGS, uncoupling between these two modes of PTGS. Second, non-toxic, but not toxic, levels of cadmium inhibited PTGS, suggesting induction of a pathway that interferes with PTGS. Third, cadmium effects on PTGS closely paralleled those on the movement of tobamoviruses, suggesting that both processes may share common steps in their systemic transport pathways. Interestingly, these effects of cadmium do not represent a general property of toxic metal ions because two other such elements, that is zinc and aluminum, did not interfere with PTGS and viral systemic movement.

Bicarbonate stimulatory action of nizatidine, a histamine H(2)-receptor antagonist, in rat duodenums.

Nizatidine, a histamine H(2)-antagonist, is known to inhibit acetylcholinesterase (AChE) activity and is used clinically as a gastroprokinetic agent as well as the anti-ulcer agent. We examined whether or not nizatidine stimulates duodenal HCO(3)(-) secretion in rats through vagal-cholinergic mechanisms by inhibiting AChE activity. Under pentobarbital anesthesia, a proximal duodenal loop was perfused with saline, and the HCO(3)(-) secretion was measured at pH 7.0 using a pH-stat method and by adding 10 mM HCl. Nizatidine, neostigmine, carbachol, famotidine or ranitidine was administered i.v. as a single injection. Intravenous administration of nizatidine (3-30 mg/kg) dose-dependently increased the HCO(3)(-) secretion, and the effect at 10 mg/kg was equivalent to that obtained by carbachol at 0.01 mg/kg. The HCO(3)(-) stimulatory action of nizatidine was observed at the doses that inhibited the histamine-induced acid secretion and enhanced gastric motility. This effect was mimicked by neostigmine (0.03 mg/kg) and significantly attenuated by bilateral vagotomy and pretreatment with atropine but not indomethacin. The IC(50) of nizatidine for AChE of rat erythrocytes was 1.4 x 10(-6) M, about 12 times higher than that of neostigmine. Ranitidine showed the anti-AchE activity and increased duodenal HCO(3)(-) secretion, similar to nizatidine, whereas famotidine had any influence on neither AChE activity nor the HCO(3)(-) secretion. On the other hand, duodenal damage induced by acid perfusion (100 mM HCl for 4 h) in the presence of indomethacin was significantly prevented by nizatidine and neostigmine, at the doses that increased the HCO(3)(-) secretion. These results suggest that nizatidine increases HCO(3)(-) secretion in the rat duodenum, mediated by vagal-cholinergic mechanism, the action being associated with the anti-AChE activity of this agent.

Tuberculosis and drug resistance among patients seen at an AIDS Reference Center in São Paulo, Brazil.

OBJECTIVES: To assess the frequency of resistance of Mycobacterium tuberculosis to antituberculosis drugs and the factors associated with it among patients with tuberculosis (TB) and acquired immunodeficiency syndrome (AIDS). MATERIALS AND METHODS: The medical records of TB and AIDS cases diagnosed from 1992 to 1997 in a public service for AIDS care were reviewed. RESULTS: Resistance was diagnosed in 82 (19%) of 431 cases. The mean and median values between the diagnosis of AIDS and the diagnosis of TB were 214.8 days and 70.5 days, respectively. Multidrug-resistant TB (MDR TB) occurred in 11.3% of cases. Of the 186 patients with no previous treatment, 13 (6.9%) presented primary MDR TB. Of the 90 cases with previous treatment, six (6.7%) presented monoresistance to rifampin and 27 (30%) presented MDR TB. The distribution of cases with sensitive and resistant M. tuberculosis strains was homogeneous in terms of the following variables: gender, age, category of exposure to human immunodeficiency virus (HIV), alcoholism, and homelessness. Multivariate analysis showed an association between resistance and the two following variables: previous treatment and duration of AIDS prior to TB exceeding 71 days. The rates of primary multiresistance and of monoresistance to rifampin were higher than those detected in HIV-negative patients in Brazil. CONCLUSIONS: In this patient series, M. tuberculosis resistance was predominantly of the acquired type, and resistance was independently associated with previous treatment for TB and with duration of AIDS prior to TB exceeding 71 days.

Effect of roxithromycin on eotaxin-primed reactive oxygen species from eosinophils.

BACKGROUND: The CC chemokine eotaxin not only attracts eosinophils to inflamed sites but also promotes adhesion, degranulation and reactive oxygen species production of eosinophils. Reactive oxygen species released from eosinophils are believed to injure epithelial cells at inflamed sites, resulting in airway hyperresponsiveness. Roxithromycin has been reported to have antiasthmatic effects, although its mechanism of action is not thoroughly understood. Therefore, the effect of roxithromycin on eotaxin-primed reactive oxygen species production from eosinophils was studied. METHODS: Reactive oxygen species production by eosinophils cultured with or without roxithromycin was evaluated using luminol-dependent chemiluminescence. RESULTS: Roxithromycin inhibited the release of reactive oxygen species from eosinophils evoked with the calcium ionophore A23187, regardless of pretreatment with or without eotaxin. CONCLUSION: Roxithromycin may protect epithelial cells at inflamed sites, at least partly by inhibiting the release of reactive oxygen species from eosinophils.

hsp65 PCR-restriction enzyme analysis (PRA) for identification of mycobacteria in the clinical laboratory.

More than 70 species of mycobacteria have been defined, and some can cause disease in humans, especially in immunocompromised patients. Species identification in most clinical laboratories is based on phenotypic characteristics and biochemical tests and final results are obtained only after two to four weeks. Quick identification methods, by reducing time for diagnosis, could expedite institution of specific treatment, increasing chances of success. PCR restriction-enzyme analysis (PRA) of the hsp65 gene was used as a rapid method for identification of 103 clinical isolates. Band patterns were interpreted by comparison with published tables and patterns available at an Internet site (http://www.hospvd.ch:8005). Concordant results of PRA and biochemical identification were obtained in 76 out of 83 isolates (91.5%). Results from 20 isolates could not be compared due to inconclusive PRA or biochemical identification. The results of this work showed that PRA could improve identification of mycobacteria in a routine setting because it is accurate, fast, and cheaper than conventional phenotypic identification.

[Mycobacterium avium complex in water buffaloes slaughtered for consumption]. / Isolemento de cepas de Mycobacterium avium em búfalos abatidos para consumo.

Two mycobacterium strains isolated from lung tissue a apical lymph nodes of slaughtered water buffaloes were biochemically analyzed and identified as Mycobacterium avium complex strains. Association between these microorganisms and the acquired immunodeficiency syndrome, and the potential risk posed by eating infected animals and their products, was discussed.

PCR-restriction enzyme analysis of a bone marrow isolate from a human immunodeficiency virus-positive patient discloses polyclonal infection with two Mycobacterium avium strains.

Polyclonal infection by Mycobacterium avium was detected by hsp65 PCR-restriction enzyme analysis (PRA) in a bone marrow isolate from an AIDS patient. Two M. avium strains, differing in colony morphology, PRA HaeIII digestion pattern, insertion element (IS) 1245 amplification, and restriction fragment length polymorphism fingerprints with IS1245 and IS1311 probes, were isolated.