Relationship of physical fitness, hormone replacement therapy, and hemostatic risk factors in postmenopausal women.

This cross-sectional study evaluated the relationship of physical fitness, hormone replacement therapy (HRT), and hemostatic profiles at rest and after an acute bout of maximal exercise in 48 healthy postmenopausal women. Subjects were categorized by fitness and HRT user status into four groups: unfit nonusers, fit nonusers, unfit users, and fit users. Fibrinolytic variables tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1) activity, and antigen and prothrombin fragment 1 + 2, a molecular marker of in vivo thrombin generation, were measured before and after maximal exercise. Fibrinogen was also measured at rest. Higher tPA and lower PAI-1 activities (P <0.05) were seen in HRT users and fit groups. tPA and PAI-1 antigens were lower in HRT and fit groups (P <0.05) but not after correction for body mass index. Prothrombin fragment 1 + 2 was lower in the fit groups regardless of HRT status (P <0.05). Fibrinogen was similar in all groups. Favorable hemostatic profiles were observed in physically fit compared with unfit women, especially in HRT nonusers. Thus fitness is more strongly related to these hemostatic risk factors compared with HRT since HRT did not affect these hemostatic variables in fit postmenopausal women.     

Neutrophils Contribute to the Protection Conferred by ArtinM against Intracellular Pathogens: A Study on Leishmania major

ArtinM, a D-mannose binding lectin from Artocarpus heterophyllus, has immunomodulatory activities through its interaction with N-glycans of immune cells, culminating with the establishment of T helper type 1 (Th1) immunity. This interaction protects mice against intracellular pathogens, including Leishmania major and Leishmania amazonensis. ArtinM induces neutrophils activation, which is known to account for both resistance to pathogens and host tissue injury. Although exacerbated inflammation was not observed in ArtinM-treated animals, assessment of neutrophil responses to ArtinM is required to envisage its possible application to design a novel immunomodulatory agent based on carbohydrate recognition. Herein, we focus on the mechanisms through which neutrophils contribute to ArtinM-induced protection against Leishmania, without exacerbating inflammation. For this purpose, human neutrophils treated with ArtinM and infected with Leishmania major were analyzed together with untreated and uninfected controls, based on their ability to eliminate the parasite, release cytokines, degranulate, produce reactive oxygen species (ROS), form neutrophil extracellular traps (NETs) and change life span. We demonstrate that ArtinM-stimulated neutrophils enhanced L. major clearance and at least duplicated tumor necrosis factor (TNF) and interleukin-1beta (IL-1β) release; otherwise, transforming growth factor-beta (TGF-β) production was reduced by half. Furthermore, ROS production and cell degranulation were augmented. The life span of ArtinM-stimulated neutrophils decreased and they did not form NETs when infected with L. major. We postulate that the enhanced leishmanicidal ability of ArtinM-stimulated neutrophils is due to augmented release of inflammatory cytokines, ROS production, and cell degranulation, whereas host tissue integrity is favored by their shortened life span and the absence of NET formation. Our results reinforce the idea that ArtinM may be considered an appropriate molecular template for the construction of an efficient anti-infective agent.     

l-Phenylalanyl-l-Glutamate-Stimulated, Chloride-Dependent Glutamate Binding Represents Glutamate Sequestration Mediated by an Exchange System

Stimulation of glutamate binding by the dipeptide L-phenylalanyl-L-glutamate (Phe-Glu) was inhibited by the peptidase inhibitor bestatin, suggesting that the stimulation was caused by glutamate liberated from the dipeptide and not by the dipeptide itself. It further suggests that this form of glutamate binding should be reinterpreted as glutamate sequestration and that stimulation of binding both by dipeptides and after preincubation with high concentrations of glutamate is likely to be due to counterflow accumulation. Several other criteria indicate that most of glutamate binding stimulated by chloride represents glutamate sequestration: Binding is reduced when the osmolarity of the incubation medium is increased, when membranes incubated with [3H]glutamate are lysed before filtration, and when membranes are made permeable by transient exposure to saponin. Moreover, dissociation of bound glutamate after a 100-fold dilution of the incubation medium is accelerated about 50 times by the addition of glutamate to the dilution medium. This result would be anomalous if glutamate were bound to a receptor site; it suggests instead that glutamate is transported in and out of membrane vesicles by a transport system that preferentially mediates exchange between internal and external glutamate. Glutamate binding contains a component of glutamate sequestration even when measured in the absence of chloride. Sequestration is adequately abolished only after treating membranes with detergents; even extensive lysis, sonication, and freezing/thawing may be insufficient.     

Deoxyribonucleic acid reassociation in the taxonomy of the genus Chlorella

DNA hybridization techniques showed Chlorella fusca var. vacuolata and C. kessleri to be homogeneous species with DNA homologies of 90–100% C. fusca var. fusca and var. rubescens, however, have only about 15% DNA homology with C. fusca var. vacuolata and should no longer be regarded as varieties. A good correlation was found so far between biochemical and physiological characters used in the taxonomy of Chlorella and DNA relatedness. Mutant strains of Chlorella were tested for DNA homologies to prove the reliability of the taxonomical interpretation.     

Conformational analysis of a cyclic thymopoietin-analogue by 1H n.m.r. spectroscopy and restrained molecular dynamics simulations

The internuclear distances of the cyclic thymopoietin derivative c[D-Val-Tyr-Arg-Lys-Glu] have been determined using two-dimensional nuclear Overhauser n.m.r. spectroscopy. These distances are used as constraints for a restrained Molecular Dynamics (MD) simulation. The two starting structures used for the calculations consist of a beta and gamma turn for model 1 and two gamma turns for model 2. The rms difference in atomic positions of the two conformations is 0.242 nm. They converge during the restrained MD simulation to the same final structure. The positional rms difference of the time averaged (5-14 ps) conformations is 0.011 nm. The hydrogen bond pattern is similar to that of model 1, but in addition we find three more gamma turns. The vicinal NH-C alpha H couplings agree well with those calculated from the time averaged structures.