Protective effect of quercetin on experimental chronic cadmium nephrotoxicity in rats is based on its antioxidant properties

Oxidative stress can play a key role in Cd-induced dysfunctions. Quercetin is a potent oxygen free radicals scavenger and a metal chelator. Our aim was to study the effect of quercetin on Cd-induced kidney damage and oxidative stress as well as its mechanism of action. Wistar rats were distributed in four experimental groups: control rats; Cd; quercetin and Cd + quercetin. Renal toxicity was evaluated by measuring urinary excretion of proteins, albumin, glucose and enzymes markers of tubular necrosis, as well as plasma concentration of creatinine. Plasma TBARS concentration and activity of antioxidant enzymes in kidney were also measured. Renal cell damage was assessed by electron microscopy. Animals that received both Cd and quercetin showed a better renal function than those receiving Cd alone. Cd-induced tubular lesions were markedly reduced in rats that also received quercetin. Cd-induced increase in plasma TBARS was prevented by the administration of quercetin. Total plasma antioxidants and renal superoxide dismutase and glutathione-reductase activities were higher in the group that received Cd and quercetin than in rats that received Cd alone. Quercetin administration does not modify the renal content or the urinary excretion of Cd. In conclusion, quercetin treatment prevents renal tubular damage and increased oxidative stress induced by chronic Cd administration, most probably throughout its antioxidant properties.     

Early human infection with Onchocerca volvulus is associated with an enhanced parasite-specific cellular immune response

The immune response after early exposure to or infection with Onchocerca volvulus was investigated in an autochthonous focus caused by the migration of infected persons to a previously unaffected area in Ecuador. Peripheral blood mononuclear cell (PBMC) proliferative and cytokine responses (interferon [IFN]-gamma and interleukin [IL]-5) to filarial antigens were measured in 14 subjects with serologic evidence of exposure and in 7 subjects with evidence of dermal microfilarial DNA and were compared with responses in 43 subjects with chronic O. volvulus infections. PBMC proliferative and cytokine responses (IFN-gamma and IL-5) to parasite antigens were elevated in the early exposure/infection group, compared with those in the chronic infection group. Addition of an IL-10-neutralizing antibody to filaria antigen-stimulated cultures resulted in significantly elevated proliferative responses in the chronic infection group. The findings suggest that early exposure and early parasite patency are associated with a vigorous cellular response, but, as infections become chronic, the cellular response becomes down-regulated, partly through an IL-10-dependent mechanism.     

Human infection with Ascaris lumbricoides is associated with a polarized cytokine response

To define the cytokine response to Ascaris lumbricoides infection, the cellular immune response to adult and larval-stage Ascaris antigens in young adults with moderate infection intensities (n=73) was compared with that of a group of uninfected control subjects (n=40). A. lumbricoides-infected subjects had significantly greater lymphoproliferative responses to adult and larval-stage antigens, compared with uninfected control subjects (P<.01). The frequencies of parasite antigen-stimulated peripheral blood mononuclear cell (PBMC)-expressing interleukin (IL)-4 and IL-5 were significantly greater in the infected group (P<.001), whereas the frequencies of IL-10- and interferon-gamma-expressing PBMC were similar in the 2 groups studied. The ratios of Th2 to Th1 cytokine frequencies were significantly elevated in the infected group, compared with those in uninfected subjects, as was IL-5 protein production by PBMC stimulated with adult (P<.05) and L3/L4 stage (P<.001) antigens. Analysis of these data indicates that A. lumbricoides infections in endemic regions are associated with a highly polarized type 2 cytokine response.     

Neurotoxic effects of three fractions isolated from Tityus serrulatus scorpion venom

Scorpion venoms contain low molecular weight basic polypeptides, neurotoxins, that are the principal toxic agents. These toxins act on ion channels, promoting a derangement that may result in an abnormal release of neurotransmitters. In the present study we investigated some of the effects of the F, H and J fractions isolated from Tityus serrulatus scorpion venom on the central nervous system of rodents. The venom was partially purified by gel filtration chromatography. The neurotoxic effect of these fractions was studied on convulsive activity after intravenous injection, and on electrographic activity and neuronal integrity of rat hippocampus when injected directly into this brain area. The results showed that intravenous injection of the F and H fractions induced convulsions, and intrahippocampal injection caused electrographic seizures in rats and neuronal damage in specific hippocampal areas. Fraction J injected intravenously reduced the general activity of mice in the open field but induced no changes when injected into the brain. These results suggest that scorpion toxins are able to act directly on the central nervous system promoting behavioural, electrographic and histological modifications.     

A community-based study of hepatitis B infection and immunization among young adults in a high-drug-use neighborhood in New York City

We conducted a community-based study of the prevalence and correlates of hepatitis B virus (HBV) infection and immunization among young adults in a “drug supermarket” neighborhood in New York City. Four hundred eighty-nine young adults ages 18–24 years were recruited from Bushwick, Brooklyn through multistage household probability sampling (n=332) and targeted sampling (n=157), interviewed, and tested for three hepatitis B markers (HBsAg, anti-HBc, and anti-HBs). Serological evidence of HBV infection was found in 8.0% (6.0% in the household sample and 12.1% in the targeted sample) and of hepatitis B immunization in 19.6% (22.6% in the household sample and 13.4% in the targeted sample). HBV infection was higher among young adults who either used crack or injected drugs and among those who traded sex for money or drugs. Having Medicaid was significantly associated with lower odds of infection in the household sample and higher odds of immunization in the targeted sample. Although adolescent hepatitis B immunization has been a public health priority in the United States since 1995, nearly three-quarters of young adults in this community did not have serological evidence of being either exposed or immunized. Whereas subsequent younger generations benefited from universal childhood hepatitis B immunization, this particular cohort of young adults who live in communities like Bushwick presents a unique group for prevention intervention. The opinions expressed herein are those of the authors and not of USAID or other organizations to which the authors belong.     

Prevalence of hyperactivity in elementary school children as a function of social system definers.

This study seeks to reconcile the widely varying estimates of prevalence of hyperactivity in children. Parents, teachers, and physicians were asked to identify hyperactive children in a sample of some 5000 elementary school children. Approximately five percent were considered hyperactive by at least one defining system; only one percent were considered hyperactive by all three definers. Prevalence rates were relatively constant from kindergarten through fifth grade.     

Interstitial lung disease in patients with ataxia-telangiectasia

Ataxia-telangiectasia (A-T) is an autosomal-recessive multiorgan disease characterized by progressive neurologic deterioration in which the most common causes of death are diseases of the respiratory system and cancers. The aim of this retrospective study was to delineate the clinical, radiographic, and pathologic manifestations of the chronic progressive interstitial lung disease seen in patients with A-T. The medical records of 97 patients with A-T and chronic lung disease were reviewed. Interstitial lung disease (ILD) was specifically diagnosed in 25 of 97 patients. None of these patients had evidence of an infectious process preceding the onset of their lung disease, and none had lasting clinical improvement after treatment with antibiotics. Although many medications were used to treat their ILD, only treatment with systemic corticosteroids early in the course of their illness was associated with clinical and radiographic improvement. Nineteen of these 25 patients with ILD died within 24 months of the onset of their ILD, and of 7 patients treated with corticosteroids, 5 are still alive. Recognition of interstitial lung disease in patients with A-T and its early treatment could reduce or eliminate pulmonary disease as a leading cause of death for these patients.