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T Heise

Publications and source records attributed to T Heise.

At least 55 records · Page 3Linked to original sources
PubMed1998

Parallel acceleration of phosphoenolpyruvate carboxykinase mRNA degradation and increase in ribonuclease activity induced by insulin in cultured rat hepatocytes.

In cultured rat hepatocytes, glucagon increased phosphoenolpyruvate carboxykinase mRNA transiently. Insulin, given at the maximal increase, enhanced the degradation by 3-fold. The levels of beta-actin mRNA and ribosomal RNA, which served as a control, remained unchanged. The transcriptional inhibitor, actinomycin D, or the serine/threonine phosphatase IIA inhibitor, okadaic acid, prevented the degradation of phosphoenolpyruvate carboxykinase mRNA. This indicated that the degradation of phosphoenolpyruvate carboxykinase mRNA requires the de novo synthesis of a bona fide destabilizing factor and/or active protein phosphatase. In vitro RNA degradation assays were developed in order to investigate whether insulin-treated cells contained enhanced ribonuclease activity. Fractionated cytosolic extracts were prepared by removing cell organelles by differential centrifugation and thereafter part of the cytosolic proteins by heat treatment. These extracts were incubated with exogenously added total RNA and the degradation of phosphoenolpyruvate carboxykinase mRNA, beta-actin mRNA and 28S ribosomal RNA was studied. In this assay, phosphoenolpyruvate carboxykinase mRNA and the otherwise stable beta-actin mRNA and ribosomal RNA were degraded 3-fold faster by extracts from insulin-treated, than from untreated, cells. The increase in RNase activity induced by insulin could be prevented by treatment of cultured rat hepatocytes with actinomycin D, indicating that ongoing gene transcription was required. The 'in vivo' specificity of the insulin effect on PCK mRNA degradation in cultured hepatocytes seemed to be lost in the in vitro assay in cytosolic extracts due to the disruption of the intracellular environment. Also in whole cell lysates, which were obtained by hypo-osmotic shock of the cells, and which contained the disrupted particulate and all soluble cellular components, PCK mRNA as well as beta-actin mRNA and ribosomal RNA, was degraded. The increase in ribonuclease activity due to insulin paralleled the insulin-induced acceleration of phosphoenolpyruvate carboxykinase mRNA degradation in cultured hepatocytes, which might indicate a functional correlation.

Animals↗
PubMed1998

Variability of the metabolic effect of soluble insulin and the rapid-acting insulin analog insulin aspart.

OBJECTIVE: To study the intra- and interindividual variability of the metabolic activity of soluble insulin and of the rapid-acting insulin analog insulin aspart after subcutaneous injection. RESEARCH DESIGN AND METHODS: A total of nine healthy male volunteers received subcutaneous injections of soluble insulin (0.2 U/kg) in the abdominal region on each of the four study days. Another 10 volunteers received an injection of insulin aspart four times. Glucose infusion rates necessary to neutralize the blood glucose-lowering effect of the administered insulin were registered during euglycemic glucose clamps (blood glucose 5.0 mmol/l; basal intravenous insulin infusion 0.15 mU x kg(-1) x min(-1) over the subsequent 600 min. We investigated the variation in metabolic activity by calculating coefficients of variation (CVs). RESULTS: In comparison to soluble insulin, subcutaneous injections of insulin aspart led to a more rapid onset of action and a shorter duration of action. Subcutaneous injection of the insulin preparations resulted in intraindividual CVs of the summary measures between 10 and 30% (soluble insulin vs. insulin aspart: maximal metabolic activity 15+/-7 vs. 16+/-10%, time to maximal metabolic activity 14+/-10 vs. 11+/-6%; NS between the preparations [means +/- SD]). The decline to half-maximal activity after maximal activity showed a lower intraindividual CV with insulin aspart (19+/-9 vs. 11+/-5%; P = 0.018). The interindividual CVs were higher than the intraindividual CVs (26 vs. 28, 23 vs. 19, and 26 vs. 17%). Generally, the pharmacodynamic variability was higher than the pharmacokinetic variability. For the pharmacokinetic measures, the intra- and interindividual variability in t(max) was lower for insulin aspart than for soluble insulin. CONCLUSIONS: The metabolic effect of soluble insulin shows an intraindividual variability of 10-20% in healthy volunteers, even under strictly controlled experimental conditions. The overall variability of action of insulin aspart was comparable to that of soluble insulin.

Adult↗
PubMed1998

Time-action profiles of novel premixed preparations of insulin lispro and NPL insulin.

OBJECTIVE: To study the pharmacodynamic properties of three premixed formulations of the rapid-acting insulin analog insulin lispro and its protamine-retarded preparation, neutral protamine lispro (NPL) insulin. RESEARCH DESIGN AND METHODS: In this open, single-center, euglycemic glucose clamp study, 30 healthy volunteers (12 women, 18 men) aged 27 +/- 2 years (mean +/- SD), whose BMI was 23.0 +/- 2.3 kg/m2, received subcutaneous injections of 0.3 U/kg body wt of insulin mixture (high-mixture 75/25, mid-mixture 50/50, or low-mixture 25/75 insulin lispro/NPL insulin), insulin lispro, or NPL insulin on one of the five study days in randomized order. Glucose infusion rates were determined over a period of 24 h after administration. RESULTS: Maximal metabolic activity decreased after subcutaneous injection of the mixtures with lower insulin lispro content; however, the time point of maximal and of early half-maximal metabolic activity was comparable among the three mixtures. Higher proportions of insulin lispro resulted in higher values for area under the curve within the first 360 min after injection and a more rapid decline to late half-maximal activity. Serum insulin concentrations showed a similar pattern. CONCLUSIONS: This study shows that the pharmacodynamic and pharmacokinetic properties of insulin lispro are preserved in stable mixtures with NPL insulin.

Adult↗
PubMed1997

Purification of a RNA-binding protein from rat liver. Identification as ferritin L chain and determination of the RNA/protein binding characteristics.

In cultured rat hepatocytes the degradation of phosphoenolpyruvate carboxykinase mRNA might be regulated by protein(s), which by binding to the mRNA alter its stability. The 3'-untranslated region of phosphoenolpyruvate carboxykinase mRNA as a potential target was used to select RNA-binding protein(s) from rat liver by the use of gel retardation assays. A cytosolic protein was isolated, which bound to the phosphoenolpyruvate carboxykinase mRNA 3'-untranslated region and other in vitro synthesized RNAs. The protein was purified to homogeneity; it had an apparent molecular mass of 400 kDa and consisted of identical subunits with an apparent size of 24.5 kDa. Sequence analysis of a tryptic peptide from the 24.5-kDa protein revealed its identity with rat ferritin light chain. Binding of ferritin to RNA was abolished after phosphorylation with cAMP-dependent protein kinase and was augmented after dephosphorylation with alkaline phosphatase. Weak binding was observed in extracts from okadaic acid-treated cultured hepatocytes compared with untreated cells. Preincubation of ferritin with an anti-phosphoserine or an anti-phosphothreonine antibody attenuated binding to RNA, while an anti-phosphotyrosine antibody generated a supershift indicating that phosphoserine and phosphothreonine but not phosphotyrosine residues were in close proximity to the RNA-binding region. Ferritin is the iron storage protein in the liver. Binding of ferritin to RNA was diminished in the presence of increasing iron concentrations, whereas the iron chelator desferal was without effect. It is concluded that ferritin might function as RNA-binding protein and that it may have important functions in the general regulation of cellular RNA metabolism.

Animals↗
PubMed1997

Time-action profile of inhaled insulin.

We compared the pharmacodynamics of insulin after inhalation of 99 U microcrystalline solid insulin and subcutaneous injection of 10 U regular insulin and intravenous injection of 5 U regular insulin. The time-action profiles of the three insulin administrations were studied in 11 healthy volunteers using the euglycaemic glucose clamp technique. The insulins were administered to each volunteer on three separate occasions in random order. Onset of action, assessed as glucose infusion rate, after insulin inhalation was substantially more rapid than after subcutaneous injection and half-maximal action was reached earlier (31 +/- 17 vs 54 +/- 12 min; p < 0.001). Maximal metabolic response was reached earlier after insulin inhalation in comparison to subcutaneous injection (108 +/- 49 vs 147 +/- 53 min; p < 0.001). The maximal glucose infusion rate after inhalation of insulin was lower than after subcutaneous insulin injection (6.2 +/2- 2.4 vs 9.1 +/- 2.5 mg kg-1 min-1; p < 0.001). The glucose infusion rates in the first 60 min after inhalation were significantly greater than after insulin injection (area under the glucose infusion rate curve: 0.23 +/- 0.12 vs 0.13 +/- 0.08 g kg-1 60 min-1; p < 0.001). However, the total metabolic effect after inhalation was significantly lower than after insulin injection (1.44 +/- 0.68 vs 1.90 +/- 0.47 g kg-1 360 min-1; p < 0.001). Relative effectiveness of inhaled insulin calculated with regard to the data from the intravenous insulin application was 9.5 +/- 4.1% and of the subcutaneous insulin application was 7.6 +/- 2.9%. With its rapid onset of action, inhaled insulin might have potential for clinical use.

Administration, Inhalation↗
PubMed1997

Comparison of the time-action profiles of U40- and U100-regular human insulin and the rapid-acting insulin analogue B28 Asp.

It is well known that rapid-acting insulin analogues like insulin aspart (B28Asp) show a faster onset and a shorter duration of action than currently available U100 soluble insulin preparations. Since this effect is mainly due to a lower concentration of slow-absorbable hexamers, the metabolic profile of human insulin in lower concentration (e.g. U40 insulin) might be more similar to that of insulin aspart. Therefore, we compared the pharmacodynamic and pharmacokinetic properties of U40 soluble insulin with insulin aspart (U100) and with U100 human insulin. Eight healthy volunteers received on different study days s.c. injection of insulin aspart and U40 insulin (0.2 U/kg body weight) under euglycaemic clamp conditions (blood glucose 5 mmol/l, basal i.v. insulin infusion 0.15 mU/kg/min). In a second study, U40 and U100 soluble insulin was administered to 9 other volunteers under similar conditions. No significant differences were observed between the summary measures of U40 and U100 insulin. Insulin aspart showed a faster onset and a shorter duration of action than U40 insulin. The metabolic activity of human insulin in concentrations of U40 and U100 is comparable. Subcutaneous injection of the insulin analogue insulin aspart leads to a faster onset and a shorter duration of action even in comparison to U40 insulin.

Adult↗
PubMed1997

Insulin aspart in a 30/70 premixed formulation. Pharmacodynamic properties of a rapid-acting insulin analog in stable mixture.

OBJECTIVE: To study the pharmacodynamic properties of a 30/70 premixed formulation of the rapid-acting insulin analog insulin aspart (B28Asp) and its protamine-retarded preparation (30/70 IA) in comparison with a respective mixture of soluble human insulin and NPH insulin (30/70 HI). RESEARCH DESIGN AND METHODS: In this single-center double-blind euglycemic glucose-clamp study, 24 healthy male volunteers (age, 26 +/- 2 years; BMI, 23.7 +/- 1.7 kg/m2) received single subcutaneous injections of 0.3 U/kg body wt of either 30/70 IA or 30/70 HI on 2 study days in randomized order. Glucose infusion rates (GIRs) were determined over a 24-h period after administration. RESULTS: The injection of 30/70 IA resulted in an earlier onset and more pronounced peak of action (tmax, 127 +/- 24 min; GIRmax 9.7 +/- 2.3 mg.kg-1.min-1) than 30/70 HI (tmax, 185 +/- 52 min; GIRmax, 7.4 +/- 1.7 mg.kg-1.min-1_ (P < 0.001). The metabolic activity of 30/70 IA (measured as the sum of the glucose infused) within the first 4 h after injection was 37% greater than that of 30/70 HI (P < 0.0001), while the total metabolic potencies over 24 h of both preparations were comparable. CONCLUSIONS: The 30/70 premixed formulation of insulin aspart shows a significantly greater metabolic effect in the first 4 h after subcutaneous injection than the 30/70 mixture of human insulin. Insulin aspart retains its pharmacodynamic properties in a premixed 30/70 formulation.

Adult↗
PubMed1996

Molecular cloning, sequencing and expression of the cDNA of the mitochondrial form of phosphoenolpyruvate carboxykinase from human liver.

In human liver, phosphoenolpyruvate carboxykinase (PCK; EC 4.1.1.32) is about equally distributed between cytosol and mitochondria in contrast with rat liver in which it is essentially a cytosolic enzyme. Recently, the isolation of the gene and cDNA of the human cytosolic enzyme has been reported [Ting, Burgess, Chamberlian, Keith, Falls and Meisler (1993) Genomics 16, 698-706; Stoffel, Xiang, Espinosa, Cox, Le Beau and Bell (1993) Hum. Mol. Genet. 2, 1-4]. It was the goal of this investigation to isolate the cDNA of the human mitochondrial form of hepatic PCK. A human liver cDNA library was screened with a rat cytosolic PCK cDNA probe comprising sequences from exons 2 to 9. A cDNA clone was isolated which had overall a 68% DNA sequence and a 70% deduced amino acid sequence identity with the human cytosolic PCK cDNA. Without the flanking 270 bases (=90 amino acids) each at the 5' and 3' end, the sequence identity was 73% on the DNA and 78% on the amino acid level. The isolated cDNA had an open reading frame of 1920 bp; it was 54 bp (equivalent to 18 amino acids) longer than that of human or rat cytosolic PCK cDNA. The isolated cDNA was cloned into the eukaryotic expression vector pcDNAI and transfected into human embryonal kidney cells HEK293; PCK activity was increased by 3-fold in the mitochondria, which normally contain 70% of total PCK activity, but not in the cytosol. The isolated cDNA was also transfected into cultured rat hepatocytes; again, PCK activity was enhanced by about 40-fold in the mitochondria, which normally possess only 10% of total PCK activity, but not in the cytosol. In the rat hepatocytes only the endogenous cytosolic PCK and not the transfected mitochondrial PCK was induced 3-fold with glucagon. Comparison of the amino acid sequences deduced from the isolated cDNA with human and rat cytosolic PCK showed that the additional 18 amino acids were located at the N-terminus of the protein and probably constitute a mitochondrial targeting signal. Northern-blot analyses revealed the human mitochondrial PCK mRNA to be 2.25 kb long, about 0.6 kb shorter than the mRNA of the cytosolic PCK. Primer extension experiments showed that the 5'-untranslated region of mitochondrial PCK mRNA was 134 nucleotides in length.

Amino Acid Sequence↗
PubMed1996

Prandial glycaemia after a carbohydrate-rich meal in type I diabetic patients: using the rapid acting insulin analogue [Lys(B28), Pro(B29)] human insulin.

The time-action profile of the insulin analogue insulin lispro ([Lys(B28), Pro(B29)] human insulin) with its rapid onset and short duration of action might be more suitable to limit hyperglycaemic excursions after a meal rich in rapidly absorbable carbohydrates in comparison to regular human insulin. A randomized, double-blind study was performed in 10 Type I diabetic patients with good metabolic control (HbA1c 7.0 +/- 0.5%). After a baseline period of 3 h (blood glucose clamped at 6.7 mmol l-1, i.v. insulin infusion of 0.2 mU kg-1 min-1 throughout the study), the patients ate a pizza, drank a cola and had a carbohydrate-rich dessert (total carbohydrate content 140 g). Immediately before the meal 15.4 +/- 3.5 U of either insulin preparation were injected subcutaneously. Blood glucose concentrations were monitored continuously thereafter. Following the injection of insulin lispro the area under the blood glucose curve after the meal was 78% of that of regular insulin (1.76 +/- 0.34 vs 2.26 +/- 0.68 mol l-1 *240 min-1; p < 0.01). Maximal blood glucose excursions were higher and were reached later after regular insulin as compared to insulin lispro (11.9 +/- 2.8 vs 9.9 +/- 1.4 mmol l-1; p < 0.05; 66 +/- 37 vs 41 +/- 7 min; p < 0.05). Maximal individual differences in the blood glucose excursions (regular human insulin minus insulin lispro) were 4.8 +/- 2.2 mmol l-1 (p < 0.0001 against zero) after 110 +/- 37 min. In Type 1 diabetic patients prandial blood glucose excursions after a carbohydrate rich meal were reduced after preprandial injection of insulin lispro in comparison to human regular insulin.

Adult↗
PubMed1995

Four week administration of an ACE inhibitor and a cardioselective beta-blocker in healthy volunteers: no influence on insulin sensitivity.

In most, but not all, studies antihypertensive treatment with angiotensin converting enzyme inhibitors (ACE inhibitors) improves insulin sensitivity, whereas beta-blockers decrease insulin sensitivity. However, there was a significant increase in body weight with beta-blockers and changes in the body potassium homeostasis with ACE inhibitors. In order to compare the drug specific metabolic effects of an ACE inhibitor and a cardioselective beta-blocker controlling these factors, we measured insulin sensitivity in a randomized, double-blind cross-over study in 22 healthy volunteers (age 27 +/- 3 years; BMI 22.0 +/- 1.5 kg m-2 (mean +/- SD)) during euglycaemic glucose clamps before and after 4 weeks' administration of 5 mg Lisinopril or 5 mg Bisoprolol. Both drug phases were separated by 4 weeks of no drug administration. During the insulin sensitivity measurements potassium concentrations were clamped at basal levels by means of a variable i.v. potassium infusion. Body weight was monitored at weekly intervals and kept constant within +/- 1 kg of the subjects' baseline weight throughout the entire study period. Insulin sensitivity did not change significantly during either drug administration period. The insulin sensitivity index of the 22 volunteers after administration of the ACE inhibitor was 7.9 +/- 2.4 mL min-1 m2 microU-1 mL-1 (basal index 8.3 +/- 1.9 mL min-1 m2 microU-1 mL-1, and 7.5 +/- 2.1 mL min-1 m2 microU-1 mL-1 after administration of the beta-blocker (basal index 8.2 +/- 1.9 mL min-1 m2 microU-1 mL-1; NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1995

Time-action profiles of the intermediate-acting insulin analogue des(64,65)-human proinsulin.

Des(64,65)-proinsulin (DPRO) is one of several endogenous intermediates arising during the conversion of proinsulin to insulin. In pharmaceutic preparations it is a clear solution containing no other proteins. Animal experiments and preliminary human studies indicated that DPRO should have a protracted time-action profile similar to that of NPH-insulin. Accordingly, we compared the time-action profiles of these two preparations, using the euglycaemic glucose clamp-technique in 9 healthy male volunteers. Different doses of DPRO (0.1, 0.15, 0.2 U/kg) or equipotent doses of NPH ( 0.2, 0.3, 0.4 U/kg) were injected subcutaneously into the abdominal wall. The maximal metabolic effect (GIRmax) of DPRO was greater than that of NPH-insulin (p < 0.05). With increasing doses, GIRmax differed significantly for DPRO but not for NPH-insulin. The time to maximal metabolic effect (tmax) was similar for the three doses of either preparation. However, tmax was reached 30 min earlier with DPRO than with NPH-insulin (p < 0.01). the decline to half-maximal after maximal activity was significantly faster with DPRO than with NPH-insulin (p < 0.0001). Subcutaneous injection of DPRO thus produced a time-action profile between that of regular insulin and NPH-insulin.

Adult↗
PubMed1994

Comparative dose-related time-action profiles of glibenclamide and a new non-sulphonylurea drug, AG-EE 623 ZW, during euglycaemic clamp in healthy subjects.

Insulin and glucose responses to glibenclamide were studied in comparison to a novel non-sulphonylurea drug (AG) by means of the euglycaemic clamp technique. Nine fasting male subjects were connected to a Biostator and 1.75, 3.5 or 7.0 mg glibenclamide or 1.0, 2.0 or 4.0 mg AG were given and blood glucose concentrations were clamped at 10% below basal values. Glucose infusion rates were registered over 10 h after administration of the tablet. Maximal glucose infusion rates after glibenclamide were 40% higher compared to AG (1.75 vs 1.0 mg, 3.5 vs 2.0 mg, 7.0 vs 4.0 mg, respectively) and were reached after 3-3.5 h for all doses. After glibenclamide, area under the glucose infusion curves and maximal incremental serum insulin responses were higher by 25-40% and by 30% compared to AG when low, medium and high doses of each drug were tested. However, a linear dose relationship was obtained for both drugs when the glucose infusion rate was plotted against the area under the insulin curve. In fact, both drugs were equipotent on a molecular weight basis. The hypoglycaemic index of both drugs (integrated glucose infusion rate divided by integrated insulin release) expressed per mumol of drug revealed a dose-dependent and parallel inverse curvilinear relation to increasing doses. This methodological approach allowed us to quantify and compare the metabolic effects of oral hypoglycaemic agents under standardised experimental conditions.

Administration, Oral↗
PubMed1993

Action profile of the rapid acting insulin analogue: human insulin B28Asp.

The time-action profile of the human insulin analogue B28Asp, which displays faster absorption rates from subcutaneous tissue compared to soluble human insulin, was studied under euglycaemic glucose clamp conditions (blood glucose 5.0 mmol l-1) in 14 healthy male volunteers. Subcutaneous injection of 0.15 U kg-1 body weight (range 9.5-14.3 U) of the insulin analogue or soluble human insulin resulted in half-maximal glucose infusion rates (after subtraction of mean baseline glucose infusion rates) that were reached significantly earlier after injection of B28Asp (45 +/- 11 (SD) min) as compared to human insulin (58 +/- 25 min, p < 0.05). Forty-five and 60 min after injection of human insulin, glucose infusion rates had increased by 3.4 +/- 1.8 and 4.8 +/- 2.3 mg min-1 kg-1 above baseline glucose infusion rates, reflecting 30 +/- 15 and 42 +/- 17% of maximal action of 10.6 +/- 2.7 mg min-1 kg-1. Following the injection of B28Asp, glucose infusion rates increased by 6.3 +/- 2.7 after 45 min and by 7.9 +/- 2.8 mg min-1 kg-1 after 60 min above baseline glucose infusion rates, reflecting 64 +/- 28% and 81 +/- 26% of maximal action of human soluble insulin (p < 0.001). Peak glucose infusion rates after injection of B28Asp were significantly higher and were reached earlier than after subcutaneous injection of soluble human insulin (p < 0.05 and p < 0.001). The human insulin analogue B28Asp showed a significantly faster onset of action as compared to soluble human insulin.

Adult↗
PubMed1993

Biotrans: description of a data transfer program for the biostator.

Glucose clamp experiments are often performed by means of a Biostator. Due to the fact that this device does not provide data storage, data analysis has to be done manually or data must be fed into the computer. In order to enhance the efficacy of data analysis and to avoid time consuming work, a data acquisition program (Biotrans) has been developed which allows data transfer from the Biostator into an IBM compatible computer. After a complex analysis of incoming data, Biotrans provides on-line data storage and display features (blood glucose concentrations and glucose infusion rate). Off-line analysis of the stored data is accomplished by conventional spread sheet programs, thus permitting complex data calculations and graphic presentation. In more than 300 glucose clamp experiments performed within the last three years Biotrans was an important tool providing data storage capabilities, better control of ongoing events during an experiment and rapid and reliable data analysis immediately after completion of individual experiments.

Glucose Clamp Technique↗
PubMed1992

[Delusion of possession in a Korean patient and therapy].

Through a Korean freechristian priest, who brought about an atmosphere of syncretism, a Korean patient was introduced by withdrawal of sleep into a shortterm state of artificial psychosis which lead to her attempting suicide. The therapeutic intervention based on the ideas of Rogers was successful in creating a basis of confidence between the patient and the doctor. Through this process it was possible to obtain further personal information, in particular concerning the patient's grandmother, who was a shamanistic mudang. In connection with the knowledge about the patient's cultural background and its ties to shamanism, and respecting the cultural content without evaluating it, a good presupposition was given for an effective therapy.

Acculturation↗
PubMed1991

Binding of cytosolic protein from cultured rat hepatocytes to the 3'-end of phosphoenolpyruvate carboxykinase mRNA--significance for protein-mediated mRNA stabilization.

In vitro transcripts of the 3'-non-translated region of the phosphoenolpyruvate carboxykinase (PCK) gene both in "sense" and "antisense" orientation bound cytosolic protein from cultured rat hepatocytes as demonstrated by electrophoretic mobility shift assay. Binding of cytosolic protein was increased 3-fold and PCK mRNA was enhanced 10-fold by treatment of the hepatocytes with 10 nM glucagon. The similar time course of the glucagon-induced increase in protein binding to PCK mRNA 3'-end and in PCK mRNA suggests that protein binding might be involved in the stabilization of PCK mRNA.

Animals↗