首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
The relative importance of fat and lean tissue mass in determining bone mineral mass among postmenopausal women was examined in this 1-year longitudinal study. Fifty postmenopausal Caucasian women entered the study; 45 of them completed a 1-year follow-up. Dual-energy X-ray absorptiometry was employed for measuring total and regional bone mineral density (BMD) and bone mineral content (BMC), fat tissue mass (FTM), lean tissue mass (LTM), and body weight. Results from linear regression analysis using the cross-sectional data (n = 50) of the study indicated that LTM explained a larger percentage of variation in bone mineral mass than did FTM. FTM and LTM were found to be moderately correlated (r = 0.55); when FTM was entered in the same predicting regression models, LTM was a significant predictor (p < 0.05) of the total and regional BMC, but not BMD. The percent FTM (and inversely %LTM) was correlated with BMD and BMC, but significant correlation was primarily found only for total body BMD (or BMC). Weight was the best predictor of total body BMD and BMC. Longitudinally (n = 45), annual changes in both FTM and weight were significantly associated with annual changes in regional BMD after adjustment for initial bone mineral values (p < 0.05). We conclude that bone mineral mass is more closely related to LTM than to FTM, while annual changes in regional BMD are more closely correlated with changes in FTM in healthy postmenopausal women. Meanwhile, increased body weight is significantly associated with increased bone mineral mass.  相似文献   

2.
Treponema pallidum DNA from even small numbers of organisms was detectable in cerebrospinal fluid (CSF) stored at room temperature or at 4 degrees C for several hours and in CSF subjected to three freeze-thaw cycles. These results suggest that negative PCR results for T. pallidum from patients diagnosed with T. pallidum invasion of the central nervous system are probably not due to the loss of target DNA prior to testing.  相似文献   

3.
An important role in O2 sensing has been assigned to microsomal and membrane-bound b-type cytochromes which generate regulatory reactive O2 species (ROS). Recently, ROS have been shown to suppress the in vitro synthesis of erythropoietin (Epo). We investigated the potential of the antioxidant vitamins A, E and C to enhance renal and hepatic Epo production. Renal effects were studied in isolated serum-free perfused rat kidneys. In control experiments without antioxidant vitamins, Epo secretion amounted to 441 +/- 23 mU/g kidney (mean +/- SEM, N = 5) during the three hour period of hypoxic perfusion (arterial pO2 35 mm Hg). Epo secretion significantly increased to 674 +/- 92 mU/g kidney (N = 7) when vitamins A (0.5 microgram/ml), E (0.5 microgram/ml) and C (10 micrograms/ml) in combination were added to the perfusion medium. The effects of the single vitamins were studied in Epo-producing hepatoma cell cultures (lines HepG2 and Hep3B). Vitamin A induced a dose-dependent increase (half-maximal stimulation at 0.2 microgram/ml) in the production of immunoreactive Epo during 24 hours of incubation (such as 680 +/- 51 U Epo/g cell protein in HepG2 cultures with 3 micrograms/ml retinol acetate compared to 261 +/- 15 U/g in untreated controls; N = 4). In contrast, vitamin E (tested from 0.05 to 500 micrograms/ml) and vitamin C (tested from 2 to 200 micrograms/ml) did not increase Epo production in hepatoma cell cultures. Thus, while vitamins E and C may have the potential to protect cells from oxidative damage, vitamin A exerts a specific stimulation of Epo production. Preliminary evidence suggests that this effect of vitamin A involves increased mRNA levels of hypoxia-inducible factor 1 alpha (HIF-1 alpha).  相似文献   

4.
BACKGROUND: Evaluate two recent tests for HIV infection diagnosis using the Enzyme-Linked Fluorescent Assay (ELFA) technique for rapid diagnosis in microbiology or virology laboratories. METHODS: A panel of 429 sera with different Ab prevalencies and different sources was prepared: 50 blood bank samples from habitual donors; 8 with positive results from other blood banks; 50 from individuals infected with HIV at various stages; 164 from subjects having practices of risk, with a prevalence of 24.4%; and 157 hospital samples selected at random, with a prevalence of 12.2%. All the samples were analyzed using IMX HIV-1/HIV-2 (ELFA A) and VIDAS HIV-1+2 (ELFA B) tests. Samples yielding positive results from either of the two tests were confirmed by WB. In the cases of indeterminate WB, p24 antigenemia was detected, the positive cases being confirmed by neutralization. RESULTS: From the panel of sera studied, 112 samples were reactive by ELFA A and 109 by ELFA B. The concordance between both assays was 97.3% for reactive samples and 99.1% for non-reactive. WB confirmation showed a global sensitivity of 100% in both tests, with a specificity of 98.4% for ELFA A and 99.3% for ELFA B. Three samples positive for both tests but indeterminate for WB corresponded to sera in the seroconversion window period, one with positive p24 antigenemia. CONCLUSIONS: The new ELFA technology is shown to be an adequate rapid, automatized diagnosis method which decreases risks from laboratory manipulation, with good sensitivity and specificity characteristics for the diagnosis of Ab HIV in health care settings.  相似文献   

5.
6.
Four experiments were conducted to determine the effects and interactions of feeding different levels of vitamins A, cholecalciferol (vitamin D3), and E on broiler chicks. In Experiment 1, chicks were fed marginal vitamin D3 (500 IU/kg) and increasing dietary levels of vitamin A (5,000, 10,000, 20,000, 40,000, 80,000, and 160,000 IU/kg). Bone ash was reduced by 10,000 IU/kg of vitamin A in the diet and at vitamin A levels above 20,000 IU/kg of diet body weight was reduced. In Experiment 2, two levels of vitamin A (1,500 and 15,000 IU/kg) and six levels of vitamin E (10, 500, 1,000, 2,500, 5,000, and 10,000 IU/kg) were added to the basal diet. High levels of vitamins A and E significantly (P < 0.001) reduced bone ash. The vitamin A x E interaction was significant (P < or = 0.05) for rickets. In Experiment 3, the same two levels of vitamin A as Experiment 2 and six levels of vitamin D3 (500, 1,000, 1,500, 2,000, 2,500, and 3,000 IU/kg) were added to the basal diet that contained 10,000 IU/kg of vitamin E. Body weight and bone ash were increased by increasing vitamin D3 with a corresponding reduction (P < or = 0.05) in rickets. In Experiment 4, three levels of vitamin A (1,500, 15,000, and 45,000 IU/kg), three levels of vitamin D3 (500, 1,500, and 2,500 IU/kg), and three levels of vitamin E (10, 5,000, and 10,000 IU/kg) were added to the basal diet. Significant negative responses (P < or = 0.05) to increasing dietary vitamin A were observed for bone ash, rickets, and plasma and liver vitamin E. A significant (P < 0.001) increase in bone ash and plasma calcium with a corresponding reduction in rickets was observed by increasing vitamin D3. Increasing dietary vitamin E adversely affected (P < or = 0.01) bone ash, plasma calcium, and plasma and liver vitamin A concentrations. These results indicate the need for making feed with the proper ratios of vitamins A, D3, and E.  相似文献   

7.
BACKGROUND: Inhibition of nitric oxide (NO) synthesis has antinatriuretic and antidiuretic effects. Limited information is available on the role of NO in tubular sodium transport in the human kidney. METHODS: We studied nine healthy, sodium-replete males with clearance techniques during maximal diuresis. NG-monomethyl-L-arginine (L-NMMA, 3 mg/kg priming dose plus 3 mg/kg/h) was infused for 3 h, to achieve steady-state inhibition of NO synthesis. Data were compared with a time control study. RESULTS: The effects of L-NMMA were quickly established and persisted through the entire infusion period. Mean arterial pressure increased slightly from 85+/-3 to 91+/-3 mmHg (P<0.05). Renal plasma flow decreased substantially, and glomerular filtration rate slightly. Large decreases in absolute sodium excretion, from 79+/-10 to 34+/-5 micromol/min (P<0.01), and fractional sodium excretion, from 0.5+/-0.0 to 0.3+/-0.0% (P<0.01), were associated with significant reductions in fractional lithium excretion (P<0.05) and maximum urine flow (P<0.01). Minimal urine sodium concentration decreased from 5.8+/-0.04 to 3.9+/-0.4 mmol/l (P<0.01) whereas minimal urine osmolality increased (P<0.05). Plasma renin activity, aldosterone and atrial natriuretic peptide levels did not change, whereas urinary excretions of guanosine 3'5'-cyclic monophosphate and of nitrite plus nitrate decreased slightly. CONCLUSIONS: Inhibition of endogenous NO synthesis in humans to an extent that raises blood pressure only mildly causes antinatriuresis, that can be attributed to increases in sodium reabsorption both at proximal and distal nephron sites. In addition, renal diluting capacity decreases. The effects in the diluting segment have not been reported before, and may be due to medullary vasoconstriction, similar to that described for angiotensin II.  相似文献   

8.
The direct inotropic effect of angiotensin II on the myocardium is still controversial and little information exists as to its potential modification by heart disorders. Therefore, this study performed simultaneous measurements of isometric force and intracellular Ca2+ concentrations ([Ca2+]i) in left ventricular papillary muscles from sham-operated and aortic-banded rats at 10 weeks post-surgery. Angiotensin II (10(-6) M) induced a reduction of peak systolic [Ca2+]i (0.56 +/- 0.03 to 0.48 +/- 0.04 microM; P<0.05) and a parallel but insignificant diminution of developed tension (10.5 +/- 1.3 to 9.6 +/- 0.8 mN/mm2) in normal papillary muscles from sham-operated animals. Hypertrophied papillary muscles from aortic-banded rats demonstrated a significant decline in both peak systolic [Ca2+]i (0.51 +/- 0.02 to 0.44 +/- 0.01 microM; P<0.05) and developed tension (8.4 +/- 1.1 to 6.8 +/- 1.7 mN/mm2; P<0.05) after addition of angiotensin II. The time courses of the mechanical contraction and the intracellular Ca2+ signal were prolonged by angiotension II in both groups. Isoproterenol dose-dependently increased developed tension and peak systolic [Ca2+]i in papillary muscles from sham-operated rats. In contrast, the positive inotropic response to isoproterenol was markedly reduced in hypertrophied muscles despite a seemingly unimpaired increase in peak systolic [Ca2+]i. Pretreatment with angiotensin II (10(-6) M) resulted in a significant attenuation of the systolic [Ca2+]i response to isoproterenol stimulation in both normal and hypertrophied papillary muscles. Neither the bradykinin B2 antagonist icatibent (10(-6) M) nor the nitric oxide (NO) inhibitor L-NMMA (10(-6) M) abolished the depressant effects of angiotension II. Thus, ANG II induces a parallel decline of the mechanical performance and Ca2+ availability in rat myocardium. These effects are more distinct in hypertrophied than in normal muscle and become accentuated during beta-adrenergic stimulation. The underlying mechanism is not associated with the NO pathway but might involve a negative functional coupling between the angiotensin and beta-adrenergic-receptor complex.  相似文献   

9.
10.
Fat-soluble vitamins and their metabolites modulate immune function in a variety of animal species. The objective of the present study was to determine the role of fat-soluble vitamins in colostrum and milk in the development of specific aspects of immune function in the calf during the 1st wk postpartum. During this period, control calves (n = 6) were fed normal colostrum and milk, and calves in the treatment group (n = 6) were fed skimmed colostrum and skimmed milk supplemented with coconut oil. Treated calves did not experience the progressive increase in concentrations of retinol, beta-carotene, alpha-tocopherol, 1,25-dihydroxyvitamin D, or retinoic acids in serum that was observed in control calves. Acquisition of passive immunity, which is indicated by concentrations of immunoglobulin G1 in serum, was unaffected by treatment. Composition and functional capacities of populations of blood mononuclear leukocytes that were collected from birth to 7 d postpartum were also unaffected by treatment. Major changes in the function and composition of mononuclear leukocyte populations from all calves occurred during the experimental period and were unrelated to the concentrations of fat-soluble vitamins in serum. Populations of blood mononuclear leukocytes from calves were functionally hyporesponsive and compositionally different from populations of blood mononuclear leukocytes from adult nongravid cows. These differences likely reflected the immaturity of the immune system of the neonatal calf and may contribute to the increased susceptibility of the calf to infectious disease.  相似文献   

11.
12.
Early weaned piglets were divided into eight groups of 6 animals each. The animals were fed diets differing in fat quality (4% soybean oil, POZ 5 or 176) and in the content of the vitamins A (5,000 or 20,000 I.U./kg) and E (25 or 125 I.U./kg) over a period of 7 weeks. At the beginning, on day 25 and 47 blood samples were taken and analysed for vitamin A and E. In liver, heart, M. longissimus dorsi and M. semitendinosus vitamin A, E and the TBA-reactive substances were analysed. Induced lipid peroxidation was assessed by the ethane and pentane production rate in the skeletal muscle. During the weaning period a decrease in the alpha-tocopherol level was observed. In groups with the lower doses of vitamin E this effect was more pronounced. After 47 days the alpha-tocopherol concentrations in plasma and heart and skeletal muscle fell about 25-30% by offering high doses of vitamin A compared to those groups fed low doses. Oxidized fats also led to lower tocopherol concentrations in muscle tissues. Hydrocarbon production in M. longissimus dorsi and M. semitendinosus was significantly reduced in groups with the high supplement of vitamin E. A tendentially opposite effect was seen in groups supplied with high levels of vitamin A or oxidized fat. Although retinyl esters in plasma are a minor fraction of the vitamin A activity, they present 99% of the vitamin A in the liver. The distribution pattern of the different retinyl esters was independent of the amount of supplementary vitamin A. In the present experiment 20,000 U of Vitamin A reduced plasma and tissue vitamin E levels. This effect led to an increase of lipid peroxidation indicated by the higher production of hydrocarbons. The results raise concerns about further increases of vitamin A supplementation in piglet feed.  相似文献   

13.
Two studies were conducted during which 23 patients with chronic migraine were exposed to pulsing electromagnetic fields over the inner thigh. In an open study, 11 subjects kept a 2-week headache log before and after 2 to 3 weeks of exposure to pulsing electromagnetic fields for 1 hour per day, 5 days per week. The number of headaches per week decreased from 4.03 during the baseline period to 0.43 during the initial 2-week follow-up period and to 0.14 during the extended follow-up which averaged 8.1 months. In a double-blind study, 9 subjects kept a 3-week log of headache activity and were randomly assigned to receive 2 weeks of real or placebo pulsing electromagnetic field exposures as described above. They were subsequently switched to 2 weeks of the other mode, after which they kept a final 3-week log. Three additional subjects in the blind study inadvertently received half-power pulsing electromagnetic field exposures. The 6 subjects exposed to the actual device first showed a change in headache activity from 3.32 per week to 0.58 per week. The 3 subjects exposed to only half the dose showed no change in headache activity. Large controlled studies should be performed to determine whether this intervention is actually effective.  相似文献   

14.
15.
BACKGROUND: According to the German Guidelines for Hemotherapy, preoperative autologous blood donations can be stored and transfused as whole blood. In contrast to the storage of blood components, however, storage of whole blood results in deterioration of the biological quality due to contamination with leukocytes and platelets. In this study we examined the influence of prestorage leukocyte depletion on the quality of filtered whole blood donations during storage. MATERIAL AND METHODS: Whole blood was donated by healthy volunteers (n = 14,500 ml, 70 ml CPDA-1) and was filtered using an integrated whole blood filter system (Leukotrap A1, Fa.Pall, Dreieich, Germany). The leukocyte-depleted whole blood units were then stored for up to 49 days. Several hematological and biochemical parameters indicative of the quality of blood donations were determined during storage. RESULTS: Our data indicate a quality of leukocyte-depleted whole blood donations comparable to buffy-coat-free red blood cell units. CONCLUSIONS: The Leukotrap A1 whole blood filter system is an interesting option for hospitals lacking the technical capacity to separate whole blood into components. The clinical suitability remains to be investigated by means of clinical studies.  相似文献   

16.
OBJECTIVE: To determine whether angiotensinogen (AGT) and angiotensin II type 1 (AT1) receptor genes contribute to the development of arterial hypertension in members of French Caucasian families and in subjects with hypertension associated with non-insulin-dependent diabetes mellitus (NIDDM). METHODS: Sibpair linkage analyses were performed with microsatellites near the AGT and AT1 receptor genes in 179 hypertensive sibpairs from 69 NIDDM kindreds. In addition, population/association studies were performed with the M235T and T174M polymorphisms of the AGT gene, and the A1166C polymorphism of the AT1 receptor gene. RESULTS: No evidence for linkage between the AGT and AT1 receptor loci and hypertension was observed. In addition, the distributions of genotypes of AGT and AT1 receptor gene polymorphisms did not differ significantly among a group of unrelated individuals with both hypertension and NIDDM (n = 188) and three groups of unrelated control subjects with NIDDM (n = 117), hypertension (n = 75) or none of these conditions (n = 125). CONCLUSIONS: These results suggest that the AGT and AT1 receptor genes are not major genetic determinants of hypertension associated with NIDDM in this population, although we can not exclude the possibility that these loci make a minor contribution in a polygenic context.  相似文献   

17.
These experiments were conducted to examine ultrastructural changes in longissimus from normal and callipyge lamb during 14 d of postmortem storage at 4 degrees C. Six crossbred ewe lambs (1/2 Dorset x 1/2 Romanov) were grain-fed and slaughtered at approximately 250 d of age. Leg conformation score was the basis for classifying carcasses into normal and callipyge. The normal and callipyge longissimus had mean Warner-Bratzler shear force of 2.8 (2.7, 2.4, and 3.4) and 9.0 (12.2, 6.9, and 7.9) kg, respectively, after 14 d of postmortem storage. The results of transmission electron microscopy demonstrated ultrastructural changes, including sarcolemma detachment, loss of myofibril lateral attachments, and I-band breaks in normal longissimus. Detachment of sarcolemma from myofibrils occurred in both phenotypes, but it was delayed by several days in callipyge longissimus. Thus, the sarcolemma detachment seems not to contribute significantly to postmortem tenderization. The endomysium of both phenotypes did not change with postmortem storage. In normal longissimus, the percentage of fractured I-bands increased from 0% at d 1 to 11% at d 3 (P<.05) and did not change between 3 and 14 d (15%) postmortem (P>.05). However, postmortem storage did not affect (0 to 3%) the frequency of the I-band breaks in the callipyge longissimus (P>.05). Therefore, the break in the I-band region in postmortem muscle is a change that is associated with postmortem tenderization. We conclude that the major factor responsible for the toughness of meat from callipyge longissimus is the postmortem stability of myofibrils.  相似文献   

18.
The choanal atresia is a rare congenital malformation. Its clinical diagnosis is easy and must be done at the birth by the midwife or the obstetrician. We recommend the aspiration in all hospital maternity wards. This attitude avoids the unrecognized of an unilateral choanal atresia. The authors report three cases with a successfully treatment.  相似文献   

19.
We analyzed individual cuts from clod (Triceps brachii), ribeye (Longissimus thoracis), top round (semimembranosus), and top sirloin (Gluteus medius) from 12 fed bison bulls for content of selected vitamins and selenium. The bulls came from producers in the United States and Canada and had consumed concentrate diets plus hay free choice for at least 180 d. The mean nutrient concentrations of all of the bison cuts combined were as follows (per 100 grams of wet weight): .045 mg thiamin, .253 mg vitamin B6, 2.131 microg vitamin B12, no detectable vitamin C, .848 microg vitamin A, .047 mg alpha-tocopherol, .013 mg tau-tocopherol, and 25.464 microg selenium. The nutrient content values did not differ (P > .05) among the cuts of meat. Cuts from individual bulls were different (P < .05) with regard to alpha- and tau-tocopherols, selenium, and vitamin A but not with regard to thiamin, vitamin B6, and vitamin B12. Nutrient concentrations, with the exception of one nutrient, of five bison from the same producer were similar. Great variation was observed between the alpha- and tau-tocopherols, selenium, and vitamin A contents among bison bulls but not among cuts of meat.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号