Control of human vascular smooth muscle cell proliferation by sera derived from 'experimentally stressed' individuals

Recently we reported that individuals with high scores in standardized hostility evaluation tests, when placed in a environment, may have an association with increases in a blood-borne mitogenic substance(s) for arterial smooth muscle cells. To further investigate the molecular basis for such an association, PDS [plasma derived serum with platelet derived growth factor (PDGF) removed] from individuals showing the greatest differential pre/post-stress mitogenic activity, were tested for ability to modulate changes in the steady state of the c-myc mRNA in cultured VSMC (vascular smooth muscle cells) by Northern blot analysis. Post-stress PDS resulted in a significant increase in c-myc mRNA, when compared with pre-stress PDS of the same individual. These results give further experimental support for the notion that stress (even in the form of transient, episodic psychological challenges) may affect the cardiovascular system via rapid elicited rises in serum mitogenic activity for VSMC.     

Characterization and quantification of organic anions with capillary zone electrophoresis using direct and indirect detection

A comparison of the separation and quantification capabilities of capillary zone electrophoresis (CZE) using direct and indirect detection of organic anions was conducted. A conventional CZE separation (normal polarity, electroosmotic flow toward the cathode) of phenol, benzoic acid, and 2,4-dihydroxybenzoic acid utilized direct UV absorption at 215 nM. A separation of myo-inositol 1,4,5-trisphosphate and myo-inositol hexakisphosphate utilizing a reversed polarity and an electroosmotic flow modifier (flow toward the anode) was monitored by indirect UV absorption at 250 nM. The separation buffers utilized in this study consisted of 50 mM borate buffer (pH 8.3) and IonPhor Anion PMA Electrolyte Buffer (pH 7.7) (Dionex Corp., Sunnyvale, CA, U.S.A.) for studies utilizing direct and indirect detection methods, respectively. The effect of separation voltage on the theoretical plate numbers observed for the separations was linear for both the direct and indirect systems. Sample introduction parameters investigated included electromigration injection voltage and duration, and gravity injection duration. The conventional CZE separation using direct detection gave superior precision and better agreement with theoretical predictions than the separation using indirect detection. Both systems were evaluated for quantitative accuracy using electromigration, pressure, and gravity sample introduction modes. The conventional CZE system showed superior performance with regard to sensitivity and limits of detection. Accuracy and precision in the quantitation of known standards was greatest for both systems when the gravity sample introduction mode was used.     

Direct and indirect association of the small GTPase ran with nuclear pore proteins and soluble transport factors: studies in Xenopus laevis egg extracts

Ran is a small GTPase that is required for protein import, mRNA export, and the maintenance of nuclear structures. To gain a better understanding of Ran's role in the nucleus, we have sought to use Xenopus egg extracts for the purification and characterization of proteins from egg extracts bound with a high affinity to a glutathione-S-transferase-Ran fusion protein (GST-Ran). We found that GST-Ran associates specifically with at least 10 extract proteins. We determined the identifies of six Ran-interacting proteins (Rips), and found that they include RanBP2/Nup358, Nup153, Importin beta, hsc70, RCC1, and RanBP1. On the basis of peptide sequence, a seventh Rip (p88) seems to be similar but not identical to Fug1/RanGAP1, the mammalian Ran-GTPase-activating protein. Gel filtration analysis of endogenous extract proteins suggests that Importin beta acts as a primary GTP-Ran effector. Both Ran and Importin beta are coimmunoprecipitated by anti-p340RanBP2 antibodies in the presence of nonhydrolyzable GTP analogues, suggesting that Ran-Importin beta complexes interact with p340RanBP2. Two other Rips, p18 and p88, are coprecipitated with p340RanBP2 in a nucleotide-independent manner. Analysis of the Ran-GTPase pathway in Xenopus extracts allows the examination of interactions between Ran-associated proteins under conditions that resemble in vivo conditions more closely than in assays with purified components, and it thereby allows additional insights into the molecular mechanism of nuclear transport.     

Gender-related differences in left ventricular filling dynamics in older subjects after endurance exercise training

The present study was designed to determine if gender affects the adaptive response to endurance exercise training of left ventricular filling dynamics in older individuals. Recently, it was shown that gender influences the cardiovascular responses to endurance exercise training in older subjects. Older men improve left ventricular systolic performance and increase maximal cardiac output in response to endurance exercise training, whereas older women do not. Twelve men (65 +/- 1 years old; mean +/- SE) and 10 women (64 +/- 1) were studied before and after 9 months of endurance exercise training. Maximal O2 uptake was determined during treadmill exercise. Left ventricular filling dynamics and ejection fraction (EF) at rest and during supine exercise were assessed by Tc-99m radionuclide ventriculography. When expressed relative to body weight, maximal O2 uptake (VO2 max) was increased by 24% (27.3 +/- 1.5 to 34.0 +/- 1.5 ml/kg/min; p < .01) in men and 27% (21.9 +/- 1.0 to 27.8 +/- 1.0 ml/kg/min; p < .01) in women in response to endurance exercise training. In men, the time-to-peak filling rate (TPFR) decreased (-19.8 +/- 6.7 ms; p < .05) during exercise at a comparable heart rate in response to training. In contrast, the change in TPFR in women (+2.7 +/- 6.0 ms) was small and insignificant. Peak filling rate (PFR) at rest and during exercise was similar before and after training in men and women. The change in left ventricular systolic reserve at a comparable heart rate from pre-to posttraining improved in men (delta EF 4 +/- 3%; p < .05), but not in women (-2 +/- 3%). The results indicate that the adaptive response of left ventricular filling dynamics to endurance exercise training is influenced by gender in older subjects. Older men show improvement in left ventricular filling dynamics, whereas older women do not.     

Thrombophilia in patients with hypercholesterolemia

To investigate a possible interrelationship between hypercholesterolemia and the coagulation and fibrinolytic system, the Cardiovascular Disease Risk Factor Two-Township Study in Taiwan was undertaken as a longitudinal prospective study focusing on the evolution of cardiovascular disease risk factors, with an emphasis on hemostatic factors. Hemostatic parameters measured in this study included prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, factor VIIc, factor VIIIc, antithrombin III, and plasminogen. Subjects of both sexes with hypercholesterolemia (> 6.2 mmol/L) also had significant elevations of diastolic blood pressure, plasma glucose, triglycerides, fibrinogen, and factor VIIc and reduced PT and APTT compared with subjects with lower cholesterol. The hypercholesterolemic women additionally had significant elevations of systolic blood pressure and factor VIIc. Levels of the anticoagulant factors, antithrombin III and plasminogen, were also higher in both hypercholesterolemic men and women. In men, only factor VIIIc had no statistically significant elevation. In women, only PT showed no statistical difference. Established coronary risk factors such as fibrinogen and factor VIIc showed remarkable elevations in patients of both sexes. Using Pearson correlation and multiple regression, the most significant parameter related to cholesterol level was factor VIIc. The present results show that hemostatic abnormalities do exist in patients with hypercholesterolemia, and this thrombophilic phenomenon sheds further light on the study of higher cardiovascular mortality in these subjects.     

Zinc supplementation aggravates body fat accumulation in genetically obese mice and dietary-obese mice

Human colostrum, the first product of lactation, has antioxidant properties and inhibits selected enzyme and bactericidal activities of human neutrophils. We examined the subsequent product of lactation, mature human milk, with respect to its antioxidant activities, its effects on neutrophil enzyme activities (myeloperoxidase, beta-glucuronidase, and lysozyme), and its effects on neutrophil bactericidal and phagocytic activities. Mature human milk displayed antioxidant characteristics similar to those of human colostrum, reducing cytochrome c and consuming H2O2. Mature milk also displayed colostrum-like characteristics in depressing neutrophil myeloperoxidase and beta-glucuronidase activities, but not in altering lysozyme activity. Neutrophil bactericidal activity against Staphylococcus aureus was depressed by both mature milk and colostrum, without dramatic effects on phagocytic activity. These data show that mature milk shares characteristics with human colostrum that may result in anti-inflammatory effects, but the magnitude of these effects is generally smaller.