Usefulness of different techniques for measuring body composition changes during weight loss in overweight and obese women

The objective was to compare measures from dual-energy X-ray absorptiometry (DXA), bioelectrical impedance analysis (BIA) and anthropometry with a reference four-compartment model to estimate fat mass (FM) and fat-free mass (FFM) changes in overweight and obese women after a weight-loss programme. Forty-eight women (age 39.8 +/- 5.8 years; weight 79.2 +/- 11.8 kg; BMI 30.7 +/- 3.6 kg/m2) were studied in an out-patient weight-loss programme, before and after the 16-month intervention. Women attended weekly meetings for the first 4 months, followed by monthly meetings from 4 to 12 months. Body composition variables were measured by the following techniques: DXA, anthropometry (waist circumference-based model; Antrform), BIA using Tanita (TBF-310) and Omron (BF300) and a reference four-compartment model. Body weight decreased significantly ( - 3.3 (sd 3.1) kg) across the intervention. At baseline and after the intervention, FM, percentage FM and FFM assessed by Antrform, Tanita, BF300 and DXA differed significantly from the reference method (P < or = 0.001), with the exception of FFM assessed by Tanita (baseline P = 0.071 and after P = 0.007). DXA significantly overestimated the change in FM and percentage FM across weight loss ( - 4.5 v. - 3.3 kg; P 0.05) from the reference model in any body composition variables. We conclude that these methods are widely used in clinical settings, but should not be applied interchangeably to detect changes in body composition. Furthermore, the several clinical methods were not accurate enough for tracking body composition changes in overweight and obese premenopausal women after a weight-loss programme.     

DNA content in malignant salivary gland tumours

Objective:  Our aim was to evaluate the DNA content in malignant salivary gland tumours using image cytometry and its possible relationships with clinical and morphologic findings, disease course and prognosis.
Patients and methods:  The study sample comprised 31 patients diagnosed and treated for primary malignant salivary gland tumours. Formalin-fixed, paraffin-embedded surgical specimens of all patients were Feulgen-stained for DNA content analysis by image cytometry. Statistical analysis was used to investigate possible relationships between DNA content variables and clinical and histological findings, disease course and patient survival.
Results:  Seventeen (55%) cases of our sample were graded as DNA diploid, four (13%) as DNA aneuploid and 10 (32%) as DNA multiploid. In 15 (48%) cases, the 5c exceeding rate (5cER) was higher than 1.7%. DNA ploidy correlated with N stage and tumour size. DNA ploidy and 5cER had a statistically significant prognostic influence on overall and disease-free survival in univariate analysis. However, in multivariate analysis, stage classification was the only parameter with an independent prognosis value.
Conclusion:  Abnormal DNA content is a common finding in salivary gland cancers. Our results suggest an important role of DNA content analysis in the evaluation of these tumours.     

Regulation of the mPTP by SIRT3-mediated deacetylation of CypD at lysine 166 suppresses age-related cardiac hypertrophy

Cardiac failure is a leading cause of age-related death, though its root cause remains unknown. Mounting evidence implicates a decline in mitochondrial function due to increased opening of the mitochondrial permeability transition pore (mPTP). Here we report that the NAD+-dependent deacetylase SIRT3 deacetylates the regulatory component of the mPTP, cyclophilin D (CypD) on lysine 166, adjacent to the binding site of cyclosporine A, a CypD inhibitor. Cardiac myocytes from mice lacking SIRT3 exhibit an age-dependent increase in mitochondrial swelling due to increased mPTP opening, a phenotype that is rescued by cyclosporine A. SIRT3 knockout mice show accelerated signs of aging in the heart including cardiac hypertrophy and fibrosis at 13 months of age. SIRT3 knockout mice are also hypersensitive to heart stress induced by transverse aortic constriction (TAC), as evidenced by cardiac hypertrophy, fibrosis, and increased mortality. Together, these data show for the first time that SIRT3 activity is necessary to prevent mitochondrial dysfunction and cardiac hypertrophy during aging and shed light on new pharmacological approaches to delaying aging and treating diseases in cardiac muscle and possibly other post-mitotic tissues.     

Systemic antibody response to diarrheagenic Escherichia coli and LPS O111, O157 and O55 in healthy Brazilian adults

Enterohaemorrhagic Escherichia coli (EHEC) can cause a variety of human illnesses ranging from uncomplicated diarrhoea to haemorrhagic colitis and haemolytic uremic syndrome. The serotype O157:H7 has been associated with numerous outbreaks worldwide, but in Brazil the infection is rare. Brazilian adults present antibodies reactive with the principal virulence factors of enteropathogenic E. coli (EPEC) that have many genetic and antigenic similarities with EHEC. Lipopolysaccharides (LPS) are components of outer membranes and important virulence factors of Gram‐negative bacteria. LPS O111 is present in EPEC and EHEC strains. LPS O157 is found only in EHEC strains, but it has some structural similarities with LPS O55 present in EPEC strains. This study investigates the levels of IgG and IgM seric antibodies reactive with EHEC O157:H7, EHEC O111:H–, EPEC O111:H– and the levels of anti‐LPS O111, LPS O157 and LPS O55 antibodies in healthy adults living in São Paulo, Brazil. The antibody levels were determined by an enzyme‐linked immunosorbent assay for 100 individual serum samples, and the presence of anti‐bacterial and anti‐LPS seric antibodies was confirmed. Positive correlations were found among the three kinds of antibodies. The concentrations of IgM anti‐LPS were significantly higher than those of IgG, and surprisingly, the concentrations of anti‐LPS O157 were high in view of the infrequent isolation of O157 bacteria in Brazil. Our results suggest that there is a cross‐reacting immunity to EHEC in the Brazilian population, which may be a result of the immunity to EPEC antigens. Alternatively, Brazilians may be exposed to EHEC more frequently than has previously been thought.     

G-CSF-treated granulocytes inhibit acute graft-versus-host disease

It has been shown that in vivo and in vitro treatment with G-CSF induces the generation of low-density granulocytes (LDGs), which copurify with PBMCs and inhibit IFN-gamma production by human T cells. These results prompted us to postulate an immunomodulatory role for LDGs in acute graft-versus-host disease (aGVHD). Here it is shown that in the mouse experimental model, in vivo and in vitro G-CSF treatment generates LDGs capable of inhibiting 80% of T-cell IFN-gamma production. To assess the role of these LDGs in aGVHD, lethally irradiated (C57BL/6 x BALB/c) F1 hosts were reconstituted with T cell-depleted bone marrow cells plus nylon wool-purified spleen cells from G-CSF-treated (G-NWS) or -nontreated (NWS) C57BL/6 donors. Recipients of G-NWS had a 75% survival rate in contrast to a rate of 25% in the NWS recipients. The protective effect was completely abolished, and the mortality rate was 100% if donor-cell infusion was treated with anti-Gr1. Moreover, if LDGs were infused with NWS, full protection of aGVHD was observed, and no signs of disease were evidenced by mortality rate, weight loss, or histopathology of target organs. These results revealed the unexpected immunosuppressive capacity of G-CSF based on the generation of LDGs, leading to the possibility of using these cells as inhibitors of aGVHD.     

Estimating gluconeogenesis by NMR isotopomer distribution analysis of [13C]bicarbonate and [1-13C]lactate

The gluconeogenic contribution to glucose production in livers isolated from rats fasted for 24 h was determined by 13C-NMR isotopomer distribution analysis of secreted glucose enriched from 99% [13C]bicarbonate (n = 4) and 99% [1-13C]lactate (n = 4). Experiments with 3% 2H2O were also performed, allowing the gluconeogenic contribution to be measured by the relative 2H enrichments at positions 5 and 2 of glucose. From 13C-NMR analyses, the contribution of gluconeogenesis to glucose output was estimated to be 93 +/- 3% for [13C]bicarbonate perfusion and 91 +/- 3% for [1-13C]lactate perfusion, in good agreement with the 2H-NMR analysis of the gluconeogenic contribution to glucose production (100 +/- 1% and 99 +/- 1%, respectively) and consistent with the expected negligible contribution from glycogenolysis. These results indicate that 13C-NMR analysis of glucose 13C-isotopomer distribution from either [13C]bicarbonate or [1-13C]lactate precursor provides realistic estimates of the gluconeogenic contribution to hepatic glucose output.     

Improved efficiency of hepatic mitochondrial function in rats with cholestasis induced by an acute dose of alpha-naphthylisothiocyanate

Cholestasis is a feature of many chronic human liver diseases. Previous studies pointed out an impairment of mitochondrial function as a cause of hepatocyte dysfunction leading to cholestatic liver injury. This study was aimed to evaluate liver mitochondrial bioenergetics of alpha-naphthylisothiocyanate-treated Wistar rats, an experimental model of cholestasis. Serum markers of liver injury and endogenous adenine nucleotides were measured. Changes in membrane potential, mitochondrial respiration, and alterations in mitochondrial permeability transition pore induction were monitored. In rats injected with alpha-naphthylisothiocyanate, liver injury with cholestasis developed within 48 h, as indicated by both serum enzyme activities and total bilirubin concentration. Liver mitochondria isolated from alpha-naphthylisothiocyanate-treated rats had a higher state 3 respiration, respiratory control ratio, ADP/O, and endogenous ATP/ADP ratio compared to controls. No change in state 4 respiration was observed. Associated with these parameters, cholestatic mitochondria exhibited an increased resistance to disruption of mitochondrial calcium homeostasis due to permeability transition pore induction. Hepatic mitochondria isolated from alpha-naphthylisothiocyanate-treated rats exhibited an improved efficiency. These data indicate that an adaptive response to resist cell death occurs during alpha-naphthylisothiocyanate-induced acute cholestasis.     

Interactions of combined bile acids on hepatocyte viability: cytoprotection or synergism

Cholestasis results from hepatocyte dysfunction due to the accumulation of bile acids in the cell, many of which are known to be cytotoxic. Recent evidence implicates competitive antagonism of key cytotoxic responses as the mechanism by which certain therapeutic bile acids might afford cytoprotection against cholestasis. In this work, we compare the relative cytotoxicity of bile acids in terms of dose- and time-dependence. To better elucidate the controversy related to the therapeutic use of ursodeoxycholate (UDCA) in cholestatic patients, we also evaluated the effects of bile acid combinations. Viability of Wistar rat hepatocytes in primary culture was measured by LDH leakage after 12 and 24 h exposure of cells to the various bile acids. All unconjugated bile acids caused a dose-dependent decrease in cell viability. The tauro- and glyco-conjugates of chenodeoxycholate (CDCA) and UDCA were all less toxic than the corresponding unconjugated form. Although relatively non-toxic, UDCA caused synergistic cell killing by lithocholate (LCA), CDCA, glyco-CDCA (GCDC) and tauro-CDCA (TCDC). Glycoursodeoxycholate decreased the toxicity of GCDC, but potentiated the toxicity of unconjugated CDCA and LCA. The tauro-conjugate of UDCA had no significant effect. These data suggest that at cholestatic concentrations, bile acid-induced cell death correlates with the degree of lipophilicity of individual bile acids. However, these results indicate that the reported improvement of biochemical parameters in cholestatic patients treated with UDCA is not due to a direct effect of UDCA on hepatocyte viability. Therefore, any therapeutic effect of UDCA must be secondary to some other process, such as altered membrane transport or nonparenchymal cell function.     

Hepatitis B virus variants in an HIV-HBV co-infected patient at different periods of antiretroviral treatment with and without lamivudine

Background  

Lamivudine inhibits replication of both human immunodeficiency virus (HIV) and hepatitis B virus (HBV) and is commonly used as part of antiretroviral therapy. The main limitation in the use of lamivudine is resistant mutation selection. Most of these mutations affect the YMDD motif of the HBV DNA polymerase. The resistance occurs through M550V or M550I aminoacid replacements. The M550V variation may be accompanied by L526M mutation, notably in HIV-HBV co-infected patients. The aim of this study was to investigate mutations associated with lamivudine resistance in a hemodialysis patient chronically co-infected with HIV-1 and HBV, who was submitted to several antiretroviral treatments.