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61.
Pancreatic noradrenergic nerves are activated by neuroglucopenia but not by hypotension or hypoxia in the dog. Evidence for stress-specific and regionally selective activation of the sympathetic nervous system. 下载免费PDF全文
P J Havel R C Veith B E Dunning G J Taborsky Jr 《The Journal of clinical investigation》1988,82(5):1538-1545
To determine if acute stress activates pancreatic noradrenergic nerves, pancreatic norepinephrine (NE) output (spillover) was measured in halothane-anesthetized dogs. Central neuroglucopenia, induced by intravenous 2-deoxy-D-glucose [( 2-DG] 600 mg/kg + 13.5 mg/kg-1 per min-1) increased pancreatic NE output from a baseline of 380 +/- 100 to 1,490 +/- 340 pg/min (delta = +1,110 +/- 290 pg/min, P less than 0.01). Surgical denervation of the pancreas reduced this response by 90% (delta = +120 +/- 50 pg/min, P less than 0.01 vs. intact innervation), suggesting that 2-DG activated pancreatic nerves by increasing the central sympathetic outflow to the pancreas rather than by acting directly on nerves within the pancreas itself. These experiments provide the first direct evidence of stress-induced activation of pancreatic noradrenergic nerves in vivo. In contrast, neither hemorrhagic hypotension (50 mmHg) nor hypoxia (6-8% O2) increased pancreatic NE output (delta = +80 +/- 110 and -20 +/- 60 pg/min, respectively, P less than 0.01 vs. neuroglucopenia) despite both producing increases of arterial plasma NE and epinephrine similar to glucopenia. The activation of pancreatic noradrenergic nerves is thus stress specific. Furthermore, because both glucopenia and hypotension increased arterial NE, yet only glucopenia activated pancreatic nerves, it is suggested that a regionally selective pattern of sympathetic activation can be elicited by acute stress, a condition in which sympathetic activation has traditionally been thought to be generalized and nondiscrete. 相似文献
62.
Mevalonate-mediated suppression of 3-hydroxy-3-methylglutaryl coenzyme A reductase function in alpha-toxin-perforated cells. 下载免费PDF全文
M D Giron C M Havel J A Watson 《Proceedings of the National Academy of Sciences of the United States of America》1994,91(14):6398-6402
The regulation of mevalonic acid synthesis requires both nonsterol isopentenoid and sterol regulatory signal molecules. A primary target of this multivalent control process is the enzyme which catalyzes mevalonate synthesis: 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (EC 1.1.1.34). In this report Staphylococcus aureus alpha-toxin perforated Chinese hamster ovary cells were used to facilitate the identification of isopentenoidogenic reactions and metabolites required for mevalonate-mediated loss of HMG-CoA reductase activity. alpha-Toxin-perforated cells retained the capacity to decrease, upon demand, HMG-CoA reductase activity and protein in response to mevalonate or isopentenoid pyrophosphate esters. Also, it was deduced with highly specific metabolic inhibitors, that conversion of farnesyl 1-diphosphate to squalene was required for mevalonate-mediated suppression of reductase activity. Since squalene (2 microM) did not downregulate reductase activity, pre-squalene pyrophosphate or a derivative, or polyprenyl-1-pyrophosphate-generated inorganic pyrophosphate, or a combination of these metabolites are proposed as candidate regulatory nonsterol isopentenoid signal molecules. 相似文献
63.
Very low density lipoproteins from guinea pig plasma, endogenously labeled with 3H in both the esterified and free cholesterol moieties, were obtained from serum collected 20 hr after the intravenous injection of 3H-cholesterol into donor animals. When these lipoproteins were injected into recipient guinea pigs, the esterified 3H-cholesterol was rapidly cleared from the plasma; 24% was in the liver in 5 min and 54% in 15 min. A smaller fraction of the esterified cholesterol appeared in other plasma lipoprotein fractions, with 3H in the low density lipoproteins reaching a peak of 9%-18% of the injected esterified 3H-cholesterol between 30 and 60 min after the injection. The results indicate that most of the esterified cholesterol in very low density lipoproteins of guinea pig plasma is removed directly by the liver and a minor fraction is transferred to low density lipoproteins. The pattern of labeling of cholesteryl esters of high density lipoproteins in these experiments suggests that their low concentration in the guinea pig is accompanied by a rapid turnover rate. 相似文献
64.
M Havel H Teufelsbauer P Kn?bl R Dalmatiner P Jaksch W Zw?lfer M Müller T Vukovich 《The Journal of thoracic and cardiovascular surgery》1991,101(6):968-972
To study the hemostyptic effect of aprotinin (Trasylol) in patients undergoing extracorporeal circulation for coronary artery bypass operations, we randomized 12 of 24 patients to receive aprotinin in high dosage (about 800 mg) during extracorporeal circulation. From the resulting two groups each, one patient was excluded from the study because of postoperative myocardial infarction (control group) and surgical hemorrhage (aprotinin group) leading to a second operation. Although heparin was used for anticoagulation in all 22 patients, all had a marked increase in plasma levels of thrombin-antithrombin III complexes during extracorporeal circulation, indicating an intravasal activation of coagulation. By monitoring the plasma levels of fibrin degradation products in patients without aprotinin therapy, we recorded a concomitant hyperfibrinolysis significantly less pronounced in patients receiving aprotinin (p less than 0.005). The mean total postoperative blood loss was lower in patients receiving aprotinin (620 ml) than in control patients (1000 ml; p less than 0.03). The results confirm previous reports of a hemostyptic effect of aprotinin in cardiac operations. This effect is probably due to a prevention of hyperfibrinolysis. 相似文献
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G. CONSTANTINE Research Registrar A. L. REYNOLDS Consultant D. M. LUESLEY Senior Lecturer D. G. BEEVERS Reader 《BJOG : an international journal of obstetrics and gynaecology》1987,94(12):1136-1142
Summary. Slow-release nifedipine has been used in the treatment of severe hypertension in 23 pregnant women. In 22 this was in combination with other drugs, in 18 including atenolol. Good control of blood pressure was achieved in 20 women. The perinatal mortality of the group was 130/1000, with a high caesarean section rate (71% of live-births), a high rate of abnormal CTGs, a high rate of premature delivery, and a high rate of infants who were small-for-dates. Whether this is due to the disease process or the medication is uncertain. For the present time these combinations should only be used in severe hypertensives or in the context of a controlled trial. 相似文献
68.
M. P. Havel G. Pauser P. Preiss M. M. Müller und E. Wolner 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》1986,369(1):775
Zusammenfassung Zur Prüfung der Wertigkeit von Akutphasenproteinen und Komplementfaktoren in der Frühdiagnose der intraabdominalen Infektion, wurden bei 60 Patienten nach abdominalchirurgischen Eingriffen die Antiproteasen alpha-l-Antitrypsin, alpha-2-Macroglobin, Transferrin und Antithrombin III, sowie der Komplementfaktoren C3 und C4 postoperativ bestimmt. Patienten, die eine intraabdominelle Infektion entwickelten, hatten bereits am 2. postoperativen Tag signifikant erhöhte alpha-1-Antitrypsin Plasmakonzentrationen im Vergleich zu Patienten mit unkompliziertem postoperativen Verlauf. Mittels der linearen Diskriminanzanalyse war es bereits am 2. postoperativen Tag möglich, eine kommende intraabdominele Infektion in 84% der Fälle richtig vorauszusagen. 相似文献
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