Peripheral and central injections of recombinant human interleukin-1β (IL-1β) have been shown to decrease social exploration and to induce body weight loss in rats. To characterize the receptor mechanisms of these effects, we used as a tool a specific antagonist of the receptors of IL-1, IL-1ra. Intraperitoneal (i.p.) administration of IL-1ra (8 mg/kg) blocked the effect of i.p. injection of IL-1β (4 μg/rat) on social behaviour but not on body weight. Central administration of IL-1ra (60 μg/rat, i.c.v.) abrogated the effects of centrally administered IL-1β (30 ngn/rat, i.c.v.) on both social behaviour and body weight. Central injection of IL-1ra (4 μg/rat, i.c.v.) also attenuated the effects of i.p. administered IL-1β (4 μg/rat) on social behaviour but not on body weight. These results suggest that the effects of IL-1β on social behavior are mediated centrally and that its effect on the loss of body weight involves different receptor mechanisms. 相似文献
Fluid overload predisposes chronic hemodialysis patients to cardiovascular disease, a significant cause of morbidity and mortality in these patients. We evaluated the efficacy of monitoring changes in blood volume during routine hemodialysis to detect fluid overload. Intradialytic changes in blood volume were monitored by continuously measuring hematocrit in all 56 patients in a single dialysis unit over 7 weeks. After Week 1, patients were categorized into 2 separate groups depending on their maximum intradialytic decreases in blood volume. In Group 1, 46 of 56 or 82% had greater than a 5% decrease in blood volume while in Group 2, 10 of 56 or 18% had less than a 5% decrease in blood volume. During Weeks 2–7, dialytic fluid removal was intentionally increased in Group 2 patients by 0.80 ± 0.62 L (mean ± SD) or 47 ± 43%. This intervention resulted in a larger (p < 0.02) intradialytic decrease in body weight (2.7 ± 0.9 kg versus 2.0 ± 0.8 kg) and a larger (p < 0.02) intradialytic decrease in blood volume (15 ± 5% versus 4 ± 1%) than experienced during Week 1 with a low incidence of symptoms. We conclude that there is a significant percentage of chronic hemodialysis patients who can tolerate additional fluid removal without hypovolemic symptoms even though they are considered to be at dry weight by routine physical examination and that the identification of these patients can be facilitated by intradialytic blood volume monitoring. 相似文献
In a twin sample where duration of gestation can be controlled, a specific example of the fetal origins hypothesis concerning association between low birth weight and early age at menopause is explored. The hypothesis is based on the physiologically plausible path from intrauterine growth retardation and reduced numbers of primary follicles to an earlier menopause. The sample comprised 323 Australian female twin pairs where both co-twins had reached menopause naturally and reported on their weight at birth. Regression analysis showed no linear association between the two variables (P = 0.371, r(2) = 0.0009). Intra-pair differences in age at menopause were investigated in the context of relative birth weight of co-twins. In 265 pairs an intra-pair birth weight difference was reported. In monozygotic (MZ) pairs (n = 168) this allowed for control of genetic effects as well as gestation duration. No significant differences dependent on birth weight relative to co-twin were found for age at natural menopause in either MZ or dizygotic (DZ) twin pairs, even in pairs whose birth weights differed markedly. There was some indication that twins with premature ovarian failure were heavier at birth than twins with normal or later menopausal age. We conclude that the hypothesis that lower birth weight is associated with earlier menopause is not supported by our data. 相似文献
The treatment of choice for Type II or non-insulin-dependent diabetes mellitus is a behavioral program for the management of weight. However, compliance with this lifelong dietary regimen is often poor. In the current investigation male and female adults with diagnosed Type II diabetes were randomly assigned to either a behavior modification, a cognitive modification, a cognitive-behavior modification, or a control group. Patients were evaluated in terms of weight, percentage of body fat, and glycosylated hemoglobin measures. Men lost signficantly more weight than women and subjects in the behavior modification group lost more weight and demonstrated greater decreases in diabetes control than subjects in the cognitive-behavior modification, cognitive, and control groups. A significant interaction indicated that diabetic men may benefit more from behavioral weight reduction programs than diabetic women. Several explanations for these findings are considered.This work was supported by Grants K04 HL 00809 and R01 AM 27901 from the National Institutes of Health to Robert M. Kaplan. 相似文献
Summary: Bis(phenoxy‐imine) Zr complexes with MAO activation can produce polyethylenes with well‐defined bimodal molecular weight distributions. Polymerization behavior indicates that minor changes in the ligand structures can have a significant effect on the modality of the resulting polyethylenes. Although there is no direct relationship between the bimodal catalytic behavior and the structure of a precatalyst complex in solution, a precatalyst complex having a methyl or methoxy group para to the phenoxy‐oxygen inclined to exhibit bimodal behavior whereas that with a pentafluorophenyl group on the imine‐nitrogen displayed unimodal behavior. Polymerization results suggest that bimodal behavior is linked to the presence of two kinds of cationic active species, which arise from different modes of ligand coordination. A qualitative correlation was found between the calculated amounts of possible cationic active species and the uni‐ and bimodal catalytic behavior. Based on the results obtained, we concluded that the bimodal polyethylenes are produced by two kinds of cationic active species having two available cis‐located sites with cis‐N, trans‐O and cis‐N, cis‐O arrangements. The results introduced herein are rare examples of the production of well‐defined bimodal polyethylenes using a single precatalyst.
Bis(phenoxy imine) Zr complexes can produce well‐defined bimodal polyethylenes. 相似文献
Previous studies have shown that the induction of P450 cytochrome 2E1 (CYP2E1) is associated with the loss of proteasomal activities. To correlate the loss of proteasomal activity with CYP2E1 induction, ethanol was fed intragastrically for 1, 3, 7, and 15 days. The maximum induction of CYP2E1 (3.5-fold) occurred after 15 days of ethanol feeding. However, there was no significant decrease in the 26 S chymotrypsin-like and trypsin-like activity over this period of time. When ethanol was given to rats for 1 month, CYP2E1 was significantly induced, and the proteasomal activity was significantly decreased. These results indicate that proteasomal activity was not directly affected by ethanol or CYP2E1 induction. Since 4-hydroxynonenal (4-HNE) concentration was significantly increased at 1 month of ethanol feeding, it was suspected that 4-HNE adduct formation with proteasome subunits could be the mechanism of proteasome inhibition. Using an antibody to 4-HNE adducted proteins in Western blot analysis of the 26 S proteasome fraction isolated from the liver of alcohol fed rats, one extra band appeared around 44 kDa. When the antibody to an ATPase Rpt4 was used to stain the stripped membrane, the same band that was detected with the 4-HNE antibody was detected with the Rpt4 antibody. An adduct of 4-HNE formed with the Rpt4 subunit of 26 S could impede the association of 19 S and 20 S and thus account for the observed decrease of proteasomal activity. 相似文献