Molecular size distribution of immunoreactive trypsin and renal tubular dysfunction: role in trypsin plasma-urine transfer

In order to investigate the role of circulating free trypsinogen and renal tubular dysfunction in affecting trypsin plasma-urine transfer, serum immunoreactive trypsin (IRT), its urinary output, IRT molecular size distribution, filtrable immunoreactive trypsin, gamma-glutamyltransferase and alpha-glucosidase outputs were studied in 6 control subjects, 9 patients with pancreatic cancer and 15 with chronic pancreatitis. The majority of immunoreactivity was always eluted at a molecular weight of about 24,000 and might therefore be considered as free trypsinogen. Variable amounts of IRT at higher molecular weights, possibly represented by trypsin-inhibitor complexes, were also detected. Increasing IRT levels were generally accounted for by free trypsinogen, regardless of the nature of the disease. Unlike serum free trypsinogen levels, renal tubular damage, evaluated by means of the excretion of two high-molecular weight urinary enzymes, seems to play a prominent role in explaining trypsin plasma-urine transfer.     

Length-weight relationships of ornamental fish species from Amanã Lake,Amanã Reserve,Amazonas, Brazil

Length-weight relationships (LWRs) were estimated for 16 ornamental fish species from Amanã Lake and nine tributary streams, in Central Brazilian Amazonia. Sampling was carried out bimonthly for a year (2007–2008), using two sets of four gillnets (20 m × 2 m, 2,5; 3,5; 04; 4,5 cm stretch mesh size); trawls were performed with seine nets (35 m × 6 m, 3 mm stretch mesh size); native fish-traps (fyke-net like fish-traps woven from local lianas), and dip nets (0.5 m × 0.5 m stretch mesh size). Measurements were done for standard length (SL – 0.1 cm precision) and total weight (Wt – 0.01 g precision). This study provides information on the length–weight relationships for all sampled species and, in addition, provides new maximum standard lengths for six species.     

Isopentenyl pyrophosphate, a mycobacterial non-peptidic antigen, triggers delayed and highly sustained signaling in human gamma delta T lymphocytes without inducing eown-modulation of T cell antigen receptor

The Vgamma9Vdelta2 T cell subset, which represents up to 90% of the circulating gammadelta T cells in humans, was shown to be activated, via the T cell receptor (TcR), by non-peptidic phosphorylated small organic molecules. These phosphoantigens, which are not presented by professional antigen-presenting cells, induce production of high amounts of interferon-gamma and tumor necrosis factor (TNF-alpha). To date, the specific signals triggered by these antigens have not been characterized. Here we analyze proximal and later intracellular signals triggered by isopentenyl pyrophosphate (IPP), a mycobacterial antigen that specifically stimulates Vgamma9Vdelta2 T cells, and compare these to signals induced by the non-physiological model using an anti-CD3 antibody. During antigenic stimulation we noticed that, except for the proximal p56(lck) signal, which is triggered early, the signals appear to be delayed and highly sustained. This delay, which likely accounts for the delay observed in TNF-alpha production, is discussed in terms of the ability of the antigen to cross-link and recruit transducing molecules mostly anchored to lipid rafts. Moreover, we demonstrate that, in contrast to anti-CD3 antibody, IPP does not induce down-modulation of the TcR.CD3 complex, which likely results in the highly sustained signaling and release of high levels of TNF-alpha.     

Dietary components may prevent mutation-related diseases in humans

Since it is not always possible to reduce human exposure to mutagens, attempts have been directed to identify potential antimutagens and anticarcinogens for use in protecting the population against environmental disease. The purpose of this paper is to provide the reader with information about the antimutagenic and anticarcinogenic potentials of some dietary constituents and foods widely consumed in Brazil, and to reinforce diet as a key factor in determining genomic stability and preventing human diseases. In this report, we have summarized data that show interactive effects between some dietary components and specific chemical mutagens or carcinogens using in vitro and in vivo short- or medium-term assays. The summary indicates that certain dietary compounds may be useful agents for disease prevention.     

Effects of crude extracts of Agaricus blazei on DNA damage and on rat liver carcinogenesis induced by diethylnitrosamine

The effects of crude extracts of the mushroom Agaricus blazei Murrill (Agaricaceae) on both DNA damage and placental form glutathione S-transferase (GST-P)-positive liver foci induced by diethylnitrosamine (DEN) were investigated. Six groups of adult male Wistar rats were used. For two weeks, animals of groups 3 to 6 were treated with three aqueous solutions of A. blazei (mean dry weight of solids being 1.2, 5.6, 11.5 and 11.5 mg/ml, respectively). After this period, groups 2 to 5 were given a single ip injection 200 mg/kg DEN and groups 1 and 6 were treated with 0.9% NaCl. All animals were subjected to 70% partial hepatectomy at week five and sacrificed 4, 24 and 48 h or 8 weeks after DEN or 0.9% NaCl treatments (10th week after the beginning of the experiment). The alkaline comet assay and GST-P-positive liver foci development were used to evaluate the influence of the mushroom extracts on liver cell DNA damage and on the initiation of liver carcinogenesis, respectively. Previous treatment with the highest concentration of A. blazei (11.5 mg/ml) significantly reduced DNA damage, indicating a protective effect against DEN-induced liver cytotoxicity/genotoxicity. However, the same dose of mushroom extract significantly increased the number of GST-P-positive liver foci.     

Fructose Mediated Non-Alcoholic Fatty Liver Is Attenuated by HO-1-SIRT1 Module in Murine Hepatocytes and Mice Fed a High Fructose Diet

Background

Oxidative stress underlies the etiopathogenesis of nonalcoholic fatty liver disease (NAFLD), obesity and cardiovascular disease (CVD). Heme Oxygenase-1 (HO-1) is a potent endogenous antioxidant gene that plays a key role in decreasing oxidative stress. Sirtuin1 (SIRT1) belongs to the family of NAD-dependent de-acyetylases and is modulated by cellular redox.

Hypothesis

We hypothesize that fructose-induced obesity creates an inflammatory and oxidative environment conducive to the development of NAFLD and metabolic syndrome. The aim of this study is to determine whether HO-1 acts through SIRT1 to form a functional module within hepatocytes to attenuate steatohepatitis, hepatic fibrosis and cardiovascular dysfunction.

Methods and Results

We examined the effect of fructose, on hepatocyte lipid accumulation and fibrosis in murine hepatocytes and in mice fed a high fructose diet in the presence and absence of CoPP, an inducer of HO-1, and SnMP, an inhibitor of HO activity. Fructose increased oxidative stress markers and decreased HO-1 and SIRT1 levels in hepatocytes (p<0.05). Further fructose supplementation increased FAS, PPARα, pAMPK and triglycerides levels; CoPP negated this increase. Concurrent treatment with CoPP and SIRT1 siRNA in hepatocytes increased FAS, PPARα, pAMPK and triglycerides levels suggesting that HO-1 is upstream of SIRT1 and suppression of SIRT1 attenuates the beneficial effects of HO-1. A high fructose diet increased insulin resistance, blood pressure, markers of oxidative stress and lipogenesis along with fibrotic markers in mice (p<0.05). Increased levels of HO-1 increased SIRT1 levels and ameliorated fructose-mediated lipid accumulation and fibrosis in liver along with decreasing vascular dysfunction (p<0.05 vs. fructose). These beneficial effects of CoPP were reversed by SnMP.

Conclusion

Taken together, our study demonstrates, for the first time, that HO-1 induction attenuates fructose-induced hepatic lipid deposition, prevents the development of hepatic fibrosis and abates NAFLD-associated vascular dysfunction; effects that are mediated by activation of SIRT1 gene expression.     

Adult Rat Motor Neurons Do Not Re-Establish Electrical Coupling during Axonal Regeneration and Muscle Reinnervation

Gap junctions (GJs) between neurons are present in both the newborn and the adult nervous system, and although important roles have been suggested or demonstrated in a number of instances, in many other cases a full understanding of their physiological role is still missing. GJs are expressed in the rodent lumbar cord at birth and mediate both dye and electrical coupling between motor neurons. This expression has been proposed to mediate: (i) fast synchronization of motoneuronal spike activity, in turn linked to the process of refinement of neuromuscular connections, and (ii) slow synchronization of locomotor-like oscillatory activity. Soon after birth this coupling disappears. Since in the adult rat regeneration of motor fibers after peripheral nerve injury leads to a recapitulation of synaptic refinement at the target muscles, we tested whether GJs between motor neurons are transiently re-expressed. We found that in conditions of maximal responsiveness of lumbar motor neurons (such as no depression by anesthetics, decerebrate release of activity of subsets of motor neurons, use of temporal and spatial summation by antidromic and orthodromic stimulations, testing of large ensembles of motor neurons) no firing is observed in ventral root axons in response to antidromic spike invasion of nearby counterparts. We conclude that junctional coupling between motor neurons is not required for the refinement of neuromuscular innervation in the adult.