Evaluation of progressive hepatic histopathology in long-term tamoxifen therapy

Tamoxifen (TAM) therapy is the better treatment for breast cancer and the drug use the prophylaxis of this disease in young premenopausal women. Yet, the effects associated with this therapy are unknown. To better understand the extension of this problem, we developed an animal model to mimic this therapy, aiming to evaluate its potential biochemical and histopathological changes in the liver. Young cycling female rats were treated with TAM for one, two and three months and toxicological biomarkers and liver histomorphometry were evaluated. Starting at two months, TAM-treatment prevented the normal age-dependent increase in body weight, without inducing changes in food intake. Serum levels of cholesterol and of the metabolic enzymes creatine kinase and aspartate aminotransferase were reduced in all TAM treatment periods. Serum levels of the metabolic enzymes alkaline phosphatase and lactate dehydrogenase were increased after the first month but returned to control levels upon 3 months of drug exposition. Moderate microvesicular steatosis, classified only at the first month of TAM treatment, was reduced afterwards. Our model showed an adaptive response of liver upon 3 months of treatment, suggesting that at the stated conditions, TAM will not promote hepatotoxicity. In this way, the present model may be useful in the study of possible key endocrine effects of TAM use and the search for better clinical outcomes.     

Phylodynamics of the HIV-1 CRF02_AG clade in Cameroon

Evolutionary analyses have revealed an origin of pandemic HIV-1 group M in the Congo River basin in the first part of the XX century, but the patterns of historical viral spread in or around its epicentre remain largely unexplored. Here, we combine epidemiologic and molecular sequence data to investigate the spatiotemporal patterns of the CRF02_AG clade. By explicitly integrating prevalence counts and genetic population size estimates we date the epidemic emergence of CRF02_AG at 1973.1 (1972.1, 1975.3, 95% CI). To infer the phylogeographic signature of this clade at a regional scale, we analyze pol and env time-stamped sequence data from 10 countries using a Bayesian phylogeographic approach based on an asymmetric discretized diffusion model. Our data confirms a spatial origin of CRF02_AG in the Democratic Republic of Congo (DRC) and suggests that viral dissemination to Cameroon occurred at an early stage of the evolutionary history of CRF02_AG. We find considerable support for epidemiological linkage between neighbour countries. Compilation of ethnographic data suggested that well-supported viral migration did not reflect sustained human migratory flows. Finally, using sequence data from 15 locations in Cameroon, we use relaxed random walk models to explore the spatiotemporal dynamics of CRF02_AG at a finer geographical detail. Phylogeographic dispersal in continuous space reveals that at least two distinct CRF02_AG lineages are circulating in overlapping regions that are evolving at different evolutionary and diffusion rates. In conclusion, by combining molecular and epidemiological data, our results provide a time scale for CRF02_AG, early 70s, place its spatial root in the DRC within the putative root of group-M diversity and propose a scenario of chance-exportation events for the spatiotemporal patterns of a successful HIV-1 lineage both at a regional and country-scale.     

Evaluation of calcium supplementation with algae (Lithothamnion muelleri) on metabolic and inflammatory parameters in mice fed a high refined carbohydrate-containing diet

The aim of the present study was to evaluate the potential of calcium supplementation from Lithothamnium muelleri algae on metabolic and inflammatory parameters in mice with increased adiposity. Male mice were fed and divided during 8 weeks in: control (C), a high refined carbohydrate-containing diet (HC), HC diet supplemented with 1% of Lithothamnion muelleri algae (HC?+?A) and HC diet supplemented with 0.9% calcium carbonate (HC?+?C). Animals fed HC diet had increased body weight gain and adiposity, serum glucose and cholesterol, glucose intolerance and decreased insulin sensitivity, compared to control diet. However, the HC?+?A and HC?+?C groups did not prevent these aspects and were not able to change the CD14?+?cells population in adipose tissue of animals fed HC diet. Calcium supplementation with Lithothamnium muelleri algae and calcium carbonate had no protective effect against the development of adiposity, metabolic and inflammatory alterations induced by HC diet.     

Nylon-fiber-induced neutrophil fragmentation

We have investigated the effects of mechanical elution of neutrophils from nylon-wool fiber (NWF) using the scanning electron microscope and biochemical analysis of elution fractions. We have determined that mechanical removal of neutrophils from nylon-wool fiber disrupts neutrophils adherent to nylon-wool fiber and augments release of granules, release of peripheral cytoplasmic fragments, and release of lactic dehydrogenase, a soluble cytoplasmic enzyme. Mechanical shearing of the adherent cell, and not adherence per se, causes the fragmentation. The extent of fragmentation is proportional to the NWF surface area available to neutrophils and is maximal at the temperature for optimal adherence and spreading. Agents that decrease cell spreading (n-ethylmaleimide and cold) diminish fragmentation. Cytochalasin B, an agent that destabilizes the neutrophil cortex, increases fragmentation. Fragmentation may be an important contributing cause of the abnormal morphology, function, and in vivo survival of nylon-wool-fiber procured human neutrophils. The prevention of fragmentation would appear to be necessary to insure the procurement of optimally functioning cells. Elution of NWF-adherent neutrophils in the cold might be a practical way to diminish neutrophil damage during clinical filtration leukapheresis.     

Enhancement of chemotactic factor-stimulated neutrophil oxidative metabolism by leukotriene B4

Leukotriene B4 (LTB4) is a potent primary stimulator of neutrophil chemotaxis, aggregation, and degranulation and induces superoxide production at higher concentrations. In order to determine whether LTB4 modulates neutrophil responses to oxidative stimuli, human neutrophils (PMNs) were incubated with LTB4 prior to stimulation with f-Met-Leu-Phe (fMLP, 10(-7) mol/L), opsonized zymosan (OZ, 250 micrograms/mL), or phorbol myristate acetate (PMA, 32 nmol/L). Superoxide (O2-) production by stimulated PMNs was assessed by the superoxide dismutase-inhibitable reduction of cytochrome c. LTB4 alone did not stimulate O2- production in concentrations below 10(-7) mol/L and had no effect on the O2- assay. In the concentration range of 10(-12) to 10(-8) mol/L, LTB4 did not alter O2- release induced by OZ or PMA. In contrast, LTB4-treated cells demonstrated enhanced O2- production following exposure to fMLP, and in the presence of 10 nmol/LLTB4, generated 180% +/- 41% of O-2 quantities produced by control cells (n = 23). Enhancement was LTB4 dose-dependent, was maximal in the range of 1 to 10 nmol/L LTB4, was not reversed by removal of the lipid from the medium prior to fMLP stimulation, and was not dependent on the presence of Ca++ or Mg++ in the suspending medium. Chemiluminescence of fMLP-stimulated neutrophils was increased to 323% of controls in neutrophils preincubated with 10 nmol/L LTB4. Unlike augmentation of oxidative responses to fMLP seen with other degranulating stimuli, enhancement by LTB4 was not correlated with an increase in 3H-fMLP receptor binding. These results indicate that, in addition to its primary effects on neutrophil function, LTB4 modulates PMN oxidative responses to the chemotactic peptide and, thus, may amplify the release of oxygen metabolites at inflammatory foci.     

Effects of sibutramine on abdominal fat mass, insulin resistance and blood pressure in obese hypertensive patients

OBJECTIVE: The objective of this study is to assess the effects of sibutramine on body weight, body fat distribution, insulin resistance, plasma leptin, lipid profile and blood pressure profiles in hypertensive obese patients. METHODS: Eighty-six central obese hypertensive patients (BMI = 39 +/- 5 kg/m(2), 84% of women, 48 +/- 8.5 years old) were placed on a hypocaloric diet and placebo therapy for 4 weeks. They were then randomized to receive sibutramine (10 mg) or placebo for 24 weeks. Both, before therapy and at the end of the study, the waist and hip circumferences were measured and the waist/hip ratio (WHR) was calculated; abdominal ultrasonography was performed in order to estimate the amount of subcutaneous fat (SF) and visceral fat (VF), and the visceral/subcutaneous ratio. Beyond HOMA-r, another insulin resistance index (IRIp) was calculated by means of the formula: peak of blood glucose after oral glucose load x plasma insulin level/10(4). Fasting plasma leptin and lipid levels were also determined. RESULTS: Sibutramine induced greater weight reduction than placebo (6.7 vs. 2.5%, p < 0.001). Reductions in WHR (0.97 +/- 0.08 vs. 0.94 +/- 0.07, p < 0.01), IRIp (0.11 +/- 0.07 vs. 0.09 +/- 0.06 mmol mu/l(2)) and VF (6.4 +/- 2.4-6.0 +/- 2.4 cm, p < 0.01) were observed only with sibutramine. Plasma leptin decreased with placebo (24 +/- 15 vs. 18 +/- 10 UI/l, p < 0.01), but not with sibutramine (18.8 +/- 8.4 vs. 18.2 +/- 13.2 UI/l). No clinically significant change in lipid profile was observed in both groups. Moreover, office and 24-h blood pressure values did not change during placebo or sibutramine therapy, whereas a significant increase in office heart rate, from 78.3 +/- 7.3-82 +/- 7.9 b.p.m., p = 0.02, was observed with sibutramine. CONCLUSIONS: Sibutramine therapy induced greater body weight loss than placebo in hypertensive obese patients. This was associated with WHR reduction, decreases in VF and insulin resistance. The maintenance of leptin levels during sibutramine therapy may be important to avoid weight recovery, although this finding must be confirmed by other prospective studies.     

In vivo expression of the B7 costimulatory molecule by subsets of antigen-presenting cells and the malignant cells of Hodgkin's disease

The B-lymphocyte/accessory-cell activation antigen B7 (BB1) has been shown in vitro to stimulate T-lymphocyte proliferation and cytokine production via CD28 present on the latter cells. In this study, benign lymphoid tissues, lymphomas, and extralymphoid inflammatory sites were examined immunohistochemically using anti-B7 and other relevant monoclonal antibodies. B7 was expressed by benign transformed germinal center B cells, as it was by B cells of follicular lymphomas. B7 was also expressed by a subpopulation (a mean of 31% to 65%) of macrophages and dendritic cells in a variety of lymphoid tissues. It was present in abundance on all macrophages constituting sarcoid granulomas in lymph nodes. In extralymphoid inflammation, 17% to 35% of macrophages expressed B7 only weakly. Cases of Hodgkin's disease showed expression of B7 by the majority of Reed-Sternberg cells or malignant mononuclear variants, a phenomenon that potentially contributes to the lymphocytic accumulation that is a feature of this condition. CD28+ T cells were seen in all areas where T cells were present. B7+ and CD28+ cells colocalized in, for example, lymphoid follicles, lymph node paracortex, sarcoid granulomas, and Hodgkin's disease tissue, indicating a potential for cellular interaction via these molecules at these sites.     

Normal synthesis and expression of endothelial IIb/IIIa in Glanzmann's thrombasthenia

Glanzmann's thrombasthenia is a bleeding disorder, inherited in an autosomal recessive way and characterized by an absence or deficiency of the platelet glycoprotein (GP) IIb/IIIa complex. Recently, we and others demonstrated that cultured human umbilical vein endothelial cells synthesized a membrane protein complex similar to the platelet GP IIb/IIIa complex. In this article, we demonstrate that endothelial cells isolated from the umbilical vein of a newborn with Glanzmann's thrombasthenia, as compared with normal endothelial cells, show no difference in their ability to synthesize and express this GP IIb/IIIa complex. Our results indicate that Glanzmann's thrombasthenia is not accompanied by an "endotheliopathy."