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Infusion Period (infusion + period)

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Medical Sciences	45%
Life Sciences	45%

Selected Abstracts

Insulin and glucose profiles during continuous subcutaneous insulin infusion compared with injection of a long-acting insulin in Type 2 diabetes1

DIABETIC MEDICINE, Issue 5 2008
T. Parkner
Abstract Aims To compare insulin and glucose profiles during basal continuous subcutaneous infusion of a rapid-acting insulin analogue and once daily subcutaneous injection of a long-acting insulin analogue in Type 2 diabetes. Methods Twenty-one patients with Type 2 diabetes treated with oral glucose-lowering agents were randomized in this two-period crossover study to an equivalent 24-h dose of continuous subcutaneous infusion of insulin aspart and subsequently once-daily bedtime subcutaneous injection of insulin glargine, or vice versa, for eight consecutive days. Plasma profiles of insulin and glucose were recorded. Results On the last day of each treatment period, the area under the curve (AUC) for glucose was 10% lower on the continuous subcutaneous infusion regimen compared with the insulin injection regimen (P = 0.002). This was accomplished by a flat exogenous insulin infusion profile compared with a peaking profile with injected insulin (AUC was 74% higher after injection compared with pre-injection levels (P = 0.001)). During the last 6 days in each treatment period, the intra-subject variability of exogenous fasting insulin levels in the mornings was 41% lower during insulin infusion compared with insulin injection (P = 0.012). The corresponding intra-subject variability for fasting glucose only showed a tendency to be lower during infusion as compared to the injection regimen (28%; P = 0.104). Thirteen symptomatic-only or minor hypoglycaemic episodes were recorded during the entire infusion period compared with three episodes during the injection period. Conclusions Basal continuous subcutaneous infusion of a rapid-acting insulin analogue improved plasma insulin (more flat insulin profile with a lower variability) and glucose (lower AUC) profiles compared with once-daily subcutaneous injection of a long-acting insulin analogue in Type 2 diabetes. [source]

Differential effects of NT-4, NGF and BDNF on development of neurochemical architecture and cell size regulation in rat visual cortex during the critical period

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2007
Maren Engelhardt
Abstract Development of inhibition is a crucial determinant of the time course of visual cortical plasticity. BDNF strongly affects interneuron development and the onset and closure of the critical period for ocular dominance plasticity. Less is known on the effects of NT-4 despite a clear involvement in ocular dominance plasticity. We have investigated the effects of NT-4 on interneuron development by supplying NT-4 with osmotic minipumps during two time windows overlapping the onset (P12,20) and the peak (P20,28) of the critical period. We assessed the expression of interneuronal markers and soma size maturation either after the end of the infusion periods or at the end of the critical period (P45). We found that NT-4 was very effective in regulating interneuron development. NPY, SOM and PARV neuron somata grew faster during both infusion periods whereas CR neurons only responded during the early infusion period. The effects of soma size elicited during the earlier infusion period were still present at P45. In PARV neurons, NT-4 caused a long-lasting stabilization of CB and NPY expression. Furthermore, NT-4 accelerated the expression of GAD-65 mRNA in a subset of non-PARV neurons of layer V, which normally up-regulate GAD-65 towards the end of the critical period. Most of these effects were shared by NT-4 and BDNF. Some were unexpectedly also shared by NGF, which promoted growth of layer V PARV neurons, stabilized the CB expression and accelerated the GAD-65 expression. The results suggest that neurotrophins act on critical period plasticity by strengthening inhibition. [source]

Alcohol-Induced Electrical Remodeling: Effects of Sustained Short-Term Ethanol Infusion on Ion Currents in Rabbit Atrium

ALCOHOLISM, Issue 10 2009
Roman Laszlo
Background:, In some patients, above-average alcohol consumption before occurrence of atrial fibrillation (AF) in terms of a "holiday heart syndrome" (HHS) can be determined. There is evidence that long before development of apparent alcohol-induced cardiomyopathy, above-average alcohol consumption generates an arrhythmogenic substrate which abets the onset of AF. Changes of atrial current densities in terms of an electrical remodeling after sustained short-term ethanol infusion in rabbits as a potential part of HHS pathophysiology were examined in this study. Methods:, Rabbits of the ethanol group (EG) received sustained short-term intravenous alcohol infusion for 120 hours (during infusion period, blood alcohol level did not fall below 158 mg/dl), whereas NaCl 0.9% was infused in the placebo group (PG). Using patch clamp technique in whole-cell mode, atrial current densities were measured and compared between both groups. Results:, Ethanol infusion did not alter current densities of Ito [58.7 ± 5.0 pA/pF (PG, n = 20 cells) vs. 53.9 ± 5.0 pA/pF (EG, n = 24)], Isus [11.3 ± 1.4 pA/pF (PG, n = 20) vs. 10.2 ± 1.0 pA/pF (EG, n = 24)], and IK1 [,1.6 ± 0.3 pA/pF (PG, n = 17) vs. ,2.0 ± 0.3 pA/pF (EG, n = 22)]. However, alcohol infusion resulted in a remarkable reduction of ICa,L current densities [,28.4 ± 1.8 pA/pF (PG, n = 20) vs. ,15.2 ± 1.4 pA/pF (EG, n = 22)] and INa [,75.4 ± 3.6 pA/pF (PG, n = 17) vs. ,35.4 ± 4.4 pA/pF (EG, n = 21)], respectively. Conclusion:, Sustained short-term ethanol infusion in rabbits alters atrial current densities. HHS might be favored by alcohol-induced atrial electrical remodeling. [source]

Effects of Light and Dark Beer on Hepatic Cytochrome P-450 Expression in Male Rats Receiving Alcoholic Beverages as Part of Total Enteral Nutrition

ALCOHOLISM, Issue 5 2005
Mats Hidestrand
Background: Alcoholic beverages contain many congeners in addition to ethanol. Therefore, consumption of alcoholic beverages may have considerably different effects on expression of hepatic microsomal monooxygenases than the relatively selective induction of cytochrome P-450 (CYP) 2E1 observed after consumption of pure ethanol. Methods: In the current study, we compared the effects of two beers: lager (a light roasted beer) and stout (a dark roasted beer) with those of an equivalent amount of pure ethanol on hepatic CYP expression. Beer or pure ethanol was part of a complete total enteral nutrition diet that was infused intragastrically into male Sprague Dawley rats for 21 days. At the end of the infusion period, rats were euthanized, and liver and intestinal microsomes were prepared. Expression and activity of CYP1A1/2, CYP2B1, CYP2E1, CYP3A, and CYP4A were assessed by Western immunoblotting and by using CYP enzyme,specific substrates, respectively. Results: mRNA and protein levels of CYP4A1 were elevated only in stout-treated animals. However, lauric acid 12-hydroxylase activity (a CYP4A-specific activity) was reduced (p, 0.05) in microsomes from lager- and stout-fed rats. After oxidation with potassium ferricyanide, this activity was significantly increased in microsomes from stout-fed animals. The relative expression of CYP2E1 and CYP2B1 and the activities toward p -nitrophenol, pentoxyresorufin, or benzyloxyresorufin did not differ between beers or compared with pure ethanol or controls. However, the mean expression of CYP1A2, CYP3A, and CYP4A apoproteins was greater in liver microsomes from stout-infused rats than in those from lager-infused rats, ethanol-infused rats, and diet controls (p, 0.05). In addition, although no significant differences were observed in ethoxyresorufin O-dealkylase (EROD), methoxyresorufin O-dealkylase (MROD), midazolam, or testosterone hydroxylase activities between groups, stout-infused rats had greater hepatic microsomal erythromycin N -demethylase activity than other groups (p, 0.05). Conclusions: Stout contains components other than ethanol that interact in a complex fashion with the monooxygenase system. [source]

Detection of gastric slow wave uncoupling from multi-channel electrogastrogram: validations and applications

NEUROGASTROENTEROLOGY & MOTILITY, Issue 5 2003
Z. S. Wang
Abstract Current methodology of single channel electrogastrography is unable to detect coupling or uncoupling of gastric slow waves, which is crucial for gastric emptying. In this study, a new methodology, called cross-spectral analysis method, was established to compute the coupling percentage of multi-channel gastric slow waves recorded using serosal electrodes and electrogastrogram (EGG). Two experiments were performed to validate the method and demonstrate its applications in clinical research. In experiment 1, simultaneous recordings of gastric slow waves were made in five dogs from serosal electrodes and cutaneous electrodes. In experiment 2, four-channel fasting EGGs were made in 10 volunteers for 30 min during waking and 30 min during non-rapid eye movement (REM) sleep. The validation study (experiment 1) showed that the slow wave coupling calculated from the EGGs was correlated with that computed from the serosal recordings. The gastric slow wave coupling percentages detected from both serosal and cutaneous recordings were significantly impaired during vasopressin infusion (6.3 ± 2.6 vs 62.4 ± 6.3, P < 0.001 for serosal recordings; 6.7 ± 3.0 vs 57.2 ± 2.7, P < 0.001 for cutaneous recordings), and the coupling percentages respectively calculated from serosal and cutaneous recordings were significantly correlated during the baseline recording period (R = 0.922, P < 0.05) and vasopressin infusion period (R = 0.916, P < 0.05). In experiment 2, the gastric slow wave became less coupled when healthy volunteers fell asleep. The percentage of slow wave coupling calculated from the EGGs was 68.2 ± 17.9% during waking but 41.9 ± 20.8 during non-REM sleep (P < 0.05). The method developed in this study is reliable for the detection of slow wave uncoupling from multi-channel EGGs. Gastric slow wave coupling is impaired during vasopressin infusion and sleep. These data suggest that this method has potential applications in physiological and clinical studies. [source]

Effects of C-peptide on forearm blood flow and brachial artery dilatation in patients with type 1 diabetes mellitus

ACTA PHYSIOLOGICA, Issue 3 2001
E. Fernqvist-Forbes
Recent studies suggest that C-peptide increases blood flow in both exercising and resting forearm in patients with type 1 diabetes. Now we have studied the effect of C-peptide administration on endothelial-mediated and non-endothelial-mediated arterial responses as well as central haemodynamics in 10 patients with type 1 diabetes in a placebo-controlled double-blind study. Euglycaemia was maintained with an i.v. insulin infusion before and during the study. A high-resolution ultrasound technique and Doppler echocardiography were used to assess haemodynamic functions. Brachial artery blood flow and brachial artery diameter were measured in the basal state, 1 and 10 min after reactive hyperaemia and 4 min after sublingual glyceryl trinitrate administration (GTN; endothelial-independent vasodilatation), both before and after the end of 60-min C-peptide (6 pmol kg,1 min,1) or saline infusion periods. Echocardiographic measurements were also performed before and at the end of the infusion periods. Seven healthy age-matched males served as controls for vascular studies. The patients showed a blunted brachial dilatation after reactive hyperaemia in comparison with the healthy controls (2.1 ± 0.5% vs. 9.3 ± 0.3%, P < 0.001), indicating a disturbed endothelial function. C-peptide infusion compared with saline resulted in increased basal blood flow (33 ± 6%, P < 0.001) and brachial arterial dilatation (4 ± 1%, P < 0.05). Left ventricular ejection fraction seemed to be improved (5 ± 2%, P < 0.05) at the end of C-peptide infusion compared with placebo. The vascular response to reactive hyperaemia and GTN was not affected by C-peptide infusion. Our results demonstrate that physiological concentrations of C-peptide increase resting forearm blood flow, brachial artery diameter and left ventricular systolic function in patients with type 1 diabetes. [source]

Differential effects of NT-4, NGF and BDNF on development of neurochemical architecture and cell size regulation in rat visual cortex during the critical period

Estimates of the efficiency of transfer of L -histidine from blood to milk when it is the first-limiting amino acid for secretion of milk protein in the dairy cow

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2001
Chang-Hyun Kim
Abstract The efficiency of transfer of L -histidine into milk protein was measured in two experiments in which L -histidine was infused intravenously into dairy cows eating a basal diet of grass silage and a cereal-based supplement containing feather meal. Both experiments used Latin square designs, and infusion periods lasted 10 days. In Experiment 1, histidine was infused alone at doses of 3, 6 and 9,g,day,1. The output of milk protein increased up to the 6,g,day,1 dose but fell back to the basal level when 9,g,day,1 was infused. The efficiency of transfer was highest for the 6,g,day,1 dose, for which the value was 0.38. In Experiment 2 the same three histidine doses as in Experiment 1 were used, but this time the histidine was accompanied by 8,g L -methionine, 28,g L -lysine and 2.5,g L -tryptophan, to ensure that histidine remained first-limiting over the whole dose range. The output of histidine in milk protein (Y) increased linearly with histidine dose (X) such that Y,,=,0.431 X,+,0.070 r,,=,0.998; n,,=,4, indicating an efficiency of transfer of 0.43. © 2001 Society of Chemical Industry [source]

2323: Role of nitric oxide in optic nerve head blood flow regulation during isometric exercise in healthy humans

ACTA OPHTHALMOLOGICA, Issue 2010
D SCHMIDL
Purpose Nitric oxide (NO) is an important regulator of optic nerve head (ONH) blood flow in humans. We have previously shown that NO is also involved in choroidal blood flow regulation during isometric exercise. Inhibition of NO synthase (NOS) has been reported to shift choroidal pressure,flow curves during squatting to the right. The hypothesis for the present study was that inhibition of NOS may also influence ONH blood flow during isometric exercise. Methods To test this hypothesis, a randomized, double-masked, placebo-controlled, three-way crossover study was performed in 18 healthy volunteers. Subjects received on different study days intravenous infusions of NG-monomethyl- L-arginine (L-NMMA), phenylephrine, or placebo. During these infusion periods, subjects were asked to squat for 6 minutes. ONH blood flow was assessed with laser Doppler flowmetry, and ocular perfusion pressure (OPP) was calculated from mean arterial pressure and intraocular pressure. Results L-NMMA and phenylephrine increased resting OPP (p < 0.001 versus baseline), but only L-NMMA reduced resting ONH blood flow (p = 0.02 versus baseline). The relative increase in OPP during isometric exercise was comparable with all drugs administered (p = 0.69). In addition, the change of ONH blood flow was comparable with all administered drugs (p = 0.43). Conclusion These data indicate that NO plays an important role in the regulation of ONH blood flow at baseline, but does not change the response of ONH blood flow during isometric exercise. [source]