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Biomedical subjects

J Vogt

Publications and source records attributed to J Vogt.

At least 91 records · Page 5Linked to original sources
PubMed1996

The effect of human growth hormone therapy on L-(methyl-2H3)-leucine turnover and urinary pseudouridine concentration in patients with Ullrich-Turner syndrome.

UNLABELLED: The effect of daily human growth hormone (hGH) injections (3 I.U./m2/day) on tissue anabolism was determined in six patients with Ullrich-Turner syndrome (XO) (8.7-19 years of age) using novel techniques such as whole body leucine kinetics during continuous infusion of L-(Methyl-2H3)-leucine and urinary pseudouridine (5-ribosyluracil) excretion on the one hand and traditional methods like serum urea and amino acid concentrations on the other. Pseudouridine is only found in ribonucleic acid (RNA) and is neither reincorporated nor catabolically broken down and is therefore considered an ideal index of whole body RNA turnover. The mean L-(Methyl-2H3)-leucine turnover of the six XO patients before hGH was 1.90 +/- 0.15 mumoles/kg per minute. After 3 months of hGH-treatment it had increased in three patients, whereas it had decreased in the other three. The results obtained with the stable isotope technique were correlated with the urinary pseudouridine concentrations (r = 0.68; P < 0.01). The growth rates were positively correlated with leucine turnover (r = 0.63; P < 0.02) and urinary pseudouridine concentration (r = 0.73; P < 0.006) as well as negatively correlated with the serum urea concentrations r = -0.62; P < 0.03). The decrease in the individual serum urea concentrations were tightly correlated with the hGH induced change in growth rate (r = -0.90; P < 0.01). The individual bone ages were negatively correlated with the hGH induced changes in leucine turnover (r = -0.77; P < 0.003) as well as with the urinary pseudouridine concentrations (r = -0.87; P < 0.0002). The hGH effect on leucine and RNA turnover, showing effectiveness only until a developmental age between 11 and 12 years, leads the discussion of the ideal moment of oestrogen supplementation when girls with Ullrich-Turner syndrome are treated with hGH in early adolescence. CONCLUSION: The protein metabolism of patients with Ullrich-Turner syndrome is influenced by hGH in an age dependent manner. In a clinical setting, pseudouridine, an easily determined derivative of ribonucleic acids, may be able to replace the tedious work with expensive stable isotopes when questions related to tissue anabolism are to be answered.

Adolescent↗
PubMed1996

Left atrial thrombus in a 10-month-old boy--successful thrombolysis with recombinant tissue-type plasminogen activator after open-heart surgery: review of the literature.

A 10-month-old boy with major left atrial thrombus following cardiac surgery was treated with intravenously administered recombinant tissue-type plasminogen activator (rt-PA; Actilyse, Thomae-Behring, Germany). The left atrial thrombus was diagnosed by Doppler echocardiography 8 days after complete correction of a ventricular septal defect. rt-PA therapy was administered over a 10-day period. Significant hemopericardium occurred 50 h after the start of thrombolytic therapy. rt-PA infusion was discontinued for 20 h to insert a pericardial drainage. The initial rt-PA dose was 0.1 mg/kg over 10 min followed by a continuous daily infusion of 1.7 mg/kg together with low-dose heparin. Thrombolytic therapy was restarted 20 h after pericardial drainage was inserted. The daily rt-PA dose was gradually raised to 3 mg/kg (total dose: 18 mg/kg). On day 7 and 8 a clear decrease in P-plasminogen and P-antithrombin occurred, requiring additional fresh frozen plasma and P-antithrombin concentrate substitution. One day later, without further side effects, complete thrombolysis occurred. Although hemopericardium demanded discontinuation of thrombolytic therapy, rt-PA administration, closely monitored by Doppler echocardiography, was continued, leading to complete thrombolysis of the left atrial thrombus in the early postoperative period. We consider the literature dealing with rt-PA thrombolysis in infancy we discuss this case report.

Cardiac Surgical Procedures↗
PubMed1996

Regulation of right atrial beta-adrenoceptors after cardiopulmonary resuscitation in pigs.

OBJECTIVE: to test the hypothesis that right atrial beta-adrenoceptors are down-regulated after CPR and administration of beta-adrenergic agents. METHODS: after 3 min of ventricular fibrillation and 3 min of cardiac massage, 6 pigs received adrenaline (45 micrograms/kg) intravenously before defibrillation. After restoration of spontaneous circulation, dopamine was given in order to maintain the mean arterial blood pressure stable. Right atrial beta-adrenergic binding sites were determined by an equilibration binding assay using (-)-125Iodocyanopindolol. RESULTS: plasma adrenaline (mean +/- S.E.M.) was 1.1 +/- 0.9 ng/ml (6.0 +/- 4.9 nmol/l) pre-arrest and increased to 63.8 +/- 45.8 (348.2 +/- 250.0 nmol/l) (P < 0.05) and 1034 +/- 344 ng/ml (5644 +/- 1878 nmol/l) (P < 0.05) during CPR before and after adrenaline administration. At points in time 30 and 120 min after successful CPR, plasma adrenaline was 2.4 +/- 0.5 and 1.3 +/- 0.3 ng/ml (13.1 +/- 2.7 and 7.1 +/- 1.6 nmol/l). Compared to pre-arrest, the density of high-affinity beta-adrenoceptors was 29.0 +/- 12.8 fmol/mg pre-arrest and was 69.4 +/- 21.6 and 84.2 +/- 16.7 fmol/mg (P < 0.05 vs. pre-arrest) 30 and 120 min after CPR. The density of low-affinity as well as of total binding sites was not significantly changed after CPR. CONCLUSIONS: it is concluded that markedly elevated plasma catecholamine concentrations after CPR and administration of adrenaline and dopamine do not lead to a decrease in the total density of beta-adrenoceptors but to an increase in high-affinity beta-adrenoceptors in right atrial cells.

Adrenergic beta-Agonists↗
PubMed1996

Utilization of myristic and palmitic acid in humans fed different dietary fats.

To assess the influence of dietary fat composition on the contribution of dietary myristic and palmitic acid to total fat oxidation and energy production, eight healthy men consumed diets containing 40% of total energy as fat, largely as either butter, tallow or corn oil, for 11 days. On days 8 and 11 of each diet, [1-13C]-myristic or [1-13C]-palmitic acid (20 mg kg-1 body weight) was ingested mixed with the test breakfast meal. Respiratory gas exchange was measured before, and for 9h after, consumption of the meal. Breath 13CO2 enrichments were determined hourly by isotope ratio mass spectrometry. Cumulative 9-h percentage oxidation of dietary myristic acid exceeded that of palmitic acid (P < 0.01), but neither was influenced by fat treatment [n = 8, 7.1% (1.0) (SEM), 8.6% (0.9) and 8.9% (0.6) of dietary myristic acid and 3.3% (0.7), 3.0% (0.9), and 2.5% (0.6) of dietary palmitic acid from butter, tallow and corn oil meals respectively]. Net dietary myristic acid oxidation was greater (P < 0.05) after consumption of the meal high in butter than after consumption of other fats. Net dietary palmitic acid oxidation was similar after consumption of all test meals. Precedent fat treatment had no measurable effect on net fat or carbohydrate oxidation or energy expenditure. The overall contribution of dietary myristic or palmitic acid to total fat oxidation did not exceed 1% over 9 h for any dietary fat. These results suggest that, although dietary fatty acid content is the principal determinant of net dietary fatty acid oxidation, dietary fat sources with moderate differences in fat composition do not measurably alter total energy or substrate utilization after a meal.

Adult↗
PubMed1996

Effects of epinephrine on glucose metabolism in patients with alcoholic cirrhosis.

The cirrhotic liver has been shown to be resistant to the actions of various glucoregulatory hormones. The objective of this study was to investigate the effects of epinephrine on hepatic glucose metabolism in cirrhotic patients. Thirteen cirrhotic and eight healthy subjects were studied. Hepatic glucose production and turnover of alanine and glycerol were measured using stable isotope technique before and during 70 and 150 minutes of epinephrine infusion (0.1 microgram/kg/min). beta-Adrenoreceptor binding sites and affinity in mononuclear leukocyte membranes also were determined. Hepatic glucose production and alanine turnover in normals significantly increased during epinephrine infusion, but did not change in cirrhotics. Glycerol turnover increased after 70 minutes of epinephrine infusion in both groups. Epinephrine induced a significant rise of high-affinity beta-adrenoreceptor binding sites in normals, yielding a significant correlation between hepatic glucose production and receptor density (r = .94, P < .0001). In cirrhotic patients, similar changes in the number of high-affinity beta-adrenoreceptors were observed, but no correlation with hepatic glucose production was detected. The cirrhotic liver did not respond normally to the stimulatory effect of epinephrine on hepatic glucose production. Because this blunted response was not related to changes of beta-adrenoreceptors, our findings suggest that epinephrine resistance in cirrhosis was caused by a postreceptor defect.

Adult↗
PubMed1996

Risk factors for invasive group A streptococcal infections in children with varicella: a case-control study.

OBJECTIVE: To identify characteristic clinical manifestations and potential risk factors for invasive group A streptococcal (GAS) disease in children with varicella. DESIGN AND PARTICIPANTS: A case-control study was conducted in Los Angeles and Orange Counties, CA. Cases were children with varicella who developed invasive GAS disease between January 1 and May 3, 1994 (n = 25). Controls were acquaintance, neighborhood or schoolmate children with uncomplicated varicella during the study period (n = 62). Cases were compared with controls with regard to underlying illness, child care practices, parental home health practices, health care-seeking behaviors, sociodemographic characteristics and clinical characteristics. RESULTS: Controlling for age we found that cases were more likely than controls: (1) to be cared for in the home vs. out-of-home child care (odds ratio (OR), 4.4 (95% confidence interval (95% CI), 1.1 to 17)); (2) to report having asthma (OR, 6.2 (95% CI, 1.2 to 41.0)) and to be taking albuterol (OR, 11.6 ((95% CI, 1.0 to 581)); (3) to be secondary varicella cases within a household (OR, 7.3 (95% CI, 2.2 to 25)); (4) to report fever after Day 2 of varicella; and (5) to have contacted their health care provider later than controls (Day 3.8 rather than Day 1.7, P < 0.001). CONCLUSIONS: To our knowledge this is the first case-control study exploring potential risk factors for invasive GAS disease in children with varicella. Both previously healthy children with varicella and those with underlying medical problems, including asthma, may be at increased risk for GAS complications. Interventions should be targeted to parents and health care providers to increase awareness of early signs and symptoms of invasive GAS disease in children with varicella. Additional studies are needed to confirm the associations suggested by this study between GAS complications of varicella and asthma, in-home child care, secondary vs. primary varicella household cases and delayed contact with medical care providers.

California↗
PubMed1996

Predictors of unsuccessful outcome after percutaneous mitral valvulotomy including a new echocardiographic scoring system.

BACKGROUND AND AIMS OF THE STUDY: Percutaneous mitral valvulotomy has been shown to be an accept able alternative to surgery as treatment for selected patients with severe mitral stenosis. Uncertainty still exists regarding predictors of unsuccessful outcome. MATERIALS AND METHODS: 308 patients with severe mitral stenosis underwent Inoue single balloon valvulotomy over a 48-month period and were followed up for a mean of 14.5 +/- 16.8 months (range one to 64 months). Two hundred and sixty-seven (Group I) improved clinically and remained stable throughout the follow up, while subsequent surgery was required in 41 (Group II) after 38.2 +/- 143.5 days (range one to 1,212). Clinical and echocardiographic parameters of the two groups were compared to find significant predictors of an unsuccessful outcome. RESULTS: Significant differences between the groups were observed for NYHA class (2.7 +/- 0.6 vs. 2.9 +/- 0.6, p < 0.05), mitral valve area (1.0 +/- 0.3 vs. 0.9 +/- 0.2 cm2, p < 0.01), left atrial end-systolic dimension by echo (51.3 +/- 8.0 vs. 55.4 +/- 10.2 mm, p < 0.01) and an echocardiographic scoring system including grading for eccentricity of the mitral orifice and distribution of commissural calcification (7.5 +/- 2.0 for Group I and 8.7 +/- 2.0 for Group II, p < 0.001). CONCLUSIONS: Mitral valves that are more likely to have an unsuccessful outcome can be identified by hemodynamic, clinical and echocardiographic criteria, including grading for eccentricity of the mitral orifice and distribution of commissural calcification.

Adult↗
PubMed1996

Ultrasound examination of stenotic mitral valves: an in vitro study.

To determine the feasibility of currently used, intravascular ultrasound catheters (12.5 and 20 MHz, 6F and 9F, Boston Scientific Corp., Watertown, MA) for mitral valve disease, ten excised mitral valves from patients with severe mitral stenosis were examined. The specimens were fixed in a glass cylinder perfused with water. The valves were planimetered with the intravascular ultrasound system and investigated regarding pathomorphological changes. The depth field of penetration was between 1.5 and 2 cm (3 to 4 cm diameter) in the 20 MHz catheter and between 2 and 2.5 cm (4 to 5 cm diameter) in the 12.5 MHz catheter. A good correlation of the experimentally recorded valve areas could be ascertained with the Gorlin formula (r = .71, P < .05), the Doppler echocardiography method (r = .69, time method (r = .75, p < .05), and with the two-dimensional echocardiography method (r = .69, P < .05). These results show a sufficient feasibility of the currently used, intravascular ultrasound catheters and enable further steps to be taken with regard to evaluating mitral valve morphology in vivo.

Aged↗
PubMed1996

Pathomorphological characteristics of resected mitral valves after unsuccessful valvuloplasty.

OBJECTIVE: Percutaneous mitral valvuloplasty has been shown to be an acceptable alternative to surgery as treatment for selected patients with severe mitral stenosis. We examined hemodynamic, echocardiographic, and pathomorphologic findings in a series of 308 patients undergoing balloon valvuloplasty, 41 of whom underwent subsequent surgery, in search of possible predictors of an unsuccessful outcome. INTERVENTION AND RESULTS: Patients with severe mitral stenosis underwent Inoue single ballon valvuloplasty over a 48-month period and had follow-up for a mean of 14.5+/-16.8 months (range 1 to 64 months). Of the 308 patients, 267 (Group I) were clinically improved and stable throughout follow-up, while subsequent surgery was required in 41 (Group II) after 38.2+/-143.5 days (range 1 to 1212). Significant differences between the groups were observed for NYHA class (2.7+/-0.6 vs 2.9+/-0.6, p<0.05), mitral valve area (1.0+/-0.3 vs 0.9+/-0.2 cm2, p<0.01) and left atrial endsystolic dimension by echo (51.3+/-8.0 vs 55.4+/-10.2 mm, p<0.01). Two of the 41 Group II patients underwent surgery for left to right shunting, 1 for tamponade and 2 were lost to follow-up. The excised mitral valves of the remaining 36 patients all showed calcification and/or fibrosis: 9 homogenous, 5 non-homogenous; 19 were classified as having a funnel-shaped deformity, and 3 did not fit into a discrete category. Among the funnel-shaped valves, 13 had a tear versus 6 where dilation was primarily accomplished by stretching. Only one of 9 valves with homogenous calcification was torn, whereas a tear was noted in 3 of the 5 with non-homogenous calcification. CONCLUSION: Funnel-shaped valves and those with non-homogenous distribution of calcification and/or fibrosis appear to be least suitable for balloon valvuloplasty.

Adult↗
PubMed1996

[Nitric oxide--a basic mediator of vasodilation and septic shock].

Nitric oxide is synthesized from the amino acid I-arginine by a family of enzymes, the nitric oxide synthases. The synthesis of nitric oxide by vascular endothelium is responsible for the vasodilatator tone that is essential for the regulation of blood pressure. NO also contributes to the control of platelet aggregation and the regulation of cardiac contractility. These actions are all mediated by the activation of soluble guanylate cyclase and the consequent increase in the concentration of cGMP in target cells. Several studies suggests that some diseases are related to defects in the generation or action of nitric oxide. Some of the features of septic shock, including hypotension, vascular hyporeactivity, myocardial depression and tissue damage appears to result from excess production of NO. Controlled clinical trials to assess the effects of nitric oxide synthase inhibitors on mortality and morbidity in septic shock seem justified and are already planned.

Animals↗
PubMed1995

Adjustment of metabolism, catecholamines and beta-adrenoceptors to 90 min of cycle ergometry.

Adrenaline infusion of 0.1 microgram.kg-1.min-1 in healthy volunteers results in an increase of hepatic glucose production, an increase of the absolute number of occupied beta-adrenoceptors and specific changes in metabolism. To compare these effects with the changes induced by an endogenous catecholamine release, we investigated healthy volunteers during cycle ergometry. After fasting at least 14 h seven healthy subjects exercised for 90 min at an intensity of 20% below their individual anaerobic threshold. The rate of glucose production as well as the turnover rates of alanine and leucine were calculated using stable isotope tracers. High and low affinity beta-adrenergic binding sites on lymphocytes were determined by an equilibrium binding assay with (-)125 Iodocyanopindolol. After 90 min of cycling the rate of appearance of glucose increased significantly from means of 2.0 (SD 0.2) to 2.65 (SD 0.50) mg.kg-1.min-1 with unchanged blood concentrations of glucose and lactate. The flux of the amino acids alanine and leucine decreased significantly from means of 0.91 (SD 0.21) to 0.62 (SD 0.14) mg.kg-1.min-1 and from 0.40 (SD 0.05) to 0.32 (SD 0.04) mg.kg-1.min-1, respectively. The mean free fatty acid concentration increased significantly from 0.65 (SD 0.33) to 1.27 (SD 0.45) mmol.l-1 during the endurance trial. The increase of glucose turnover and the decrease of amino acid flux point to a metabolic shift towards enhanced utilization of free fatty acids. Adrenaline and noradrenaline concentrations showed a moderate but significant increase from means of 0.61 (SD 0.20) to 0.99 (SD 0.36) nmol.l-1 and from 2.27 (SD 0.75) to 3.46 (SD 0.38) nmol.l-1, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Congenital heart disease in the 48,XXYY syndrome.

We report on an infant with severe tetralogy of Fallot, bilateral preauricular pits, and a 48,XXYY chromosomal complement. This case and evidence collected from the literature suggest that congenital heart disease may occur in the 48,XXYY syndrome more frequently than currently appreciated.

Heart Defects, Congenital↗
PubMed1995

Plasma arginine, citrulline, and ornithine kinetics in adults, with observations on nitric oxide synthesis.

The plasma fluxes of ornithine (Orn), arginine (Arg), and citrulline (Cit) and rate of conversion of labeled ornithine-to-citrulline (QOrn-->Cit) were estimated in six healthy adult men receiving an arginine-rich or arginine-free L-amino acid-based diet, each for 6 days. On day 7 an 8-h (3-h fast, 5-h fed) primed continuous intravenous infusion of L-[guanido-15N,15N] arginine, L-[ureido-13C]citrulline, L-[5,5,2H2]ornithine, and L-[5,5,5-2H3]leucine was conducted. Mean citrulline fluxes (mumol.kg-1.h-1) were 10.4-13.6 for the various conditions and/or diets and remained unchanged (P > 0.05). Arginine flux was lowered (P < 0.01) by 38% for fed state during arginine-free period. Ornithine fluxes for arginine-rich were (P < 0.01) reduced with the arginine-free diet. Rates of QOrn-->Cit declined by 30% (P < .05) during the fed arginine-free period. Short-term restriction in the dietary supply of arginine did not alter the rate of whole body nitric oxide synthesis. One subject showed a very high output of nitrate on arginine-free diet (6 times average for remaining subjects).

Adult↗
PubMed1994

Glucose and urea production and leucine, ketoisocaproate and alanine fluxes at supraphysiological plasma adrenaline concentrations in volunteers.

OBJECTIVE: To determine the magnitude and time course of adrenergic effects on metabolism in volunteers and possible implications for the use of sympathomimetics in the critically ill. DESIGN: Descriptive laboratory investigation. SUBJECTS: 7 volunteers. INTERVENTION: Primed continuous infusions of stable isotope tracers ([15N2]-urea, [6,6-D2]-glucose, [methyl-D3]-L-leucine, [15N]-L-alanine) were used. After isotopic steady state had been reached an infusion of adrenaline (0.1 microgram/kg/min) was administered (4 h). Isotopic enrichment was measured using gas chromatography-mass spectrometry and the corresponding rates of appearance were calculated. MEASUREMENTS AND MAIN RESULTS: Glucose production increased from 14.1 +/- 1.2 to 21.5 +/- 2.0 mumol/kg/min (p < 0.05) after 80 min of adrenergic stimulation and then decreased again to 17.9 +/- 1.2 mumol/kg/min after 240 min. Leucine and ketoisocaproate (KIC) fluxes were 2.3 +/- 0.2 and 2.6 +/- 0.2 mumol/kg/min, respectively, at baseline and gradually decreased to 1.8 +/- 0.2 and 2.2 +/- 0.1 mumol/kg/min, respectively, after 240 min of adrenaline infusion (both p < 0.05). Alanine flux increased from 3.7 +/- 0.5 to 6.9 +/- 0.9 mumol/kg/min (p < 0.05) after 80 min of adrenergic stimulation. Urea production slightly decreased from 4.8 +/- 0.9 to 4.3 +/- 0.8 mumol/kg/min during adrenaline (p < 0.05). CONCLUSIONS: Adrenaline induced an increase in glucose production lasting for longer than 240 min. The decrease in leucine and KIC flux suggests a reduction in proteolysis, which was supported by the decrease in urea production. The increase in alanine flux is therefore most likely due to an increase in de-novo synthesis. The ammonia donor for alanine synthesis in peripheral tissues and the target for ammonia after alanine deamination in the liver remain to be investigated. These results indicate that adrenaline infusion most probably will not promote already enhanced proteolysis in critically ill patients. Gluconeogenesis is an energy consuming process and an increase may deteriorate hepatic oxygen balance in patients.

Adult↗
PubMed1994

Transesophageal echocardiography in children with cardiac assist.

Transesophageal echocardiography (TEE) is an easy, relatively non-invasive method for evaluation of cardiac function and abnormalities during cardiac assist. We used 19 TEE in 9 children (age: 10 days-4 years, weight: 2.7-12 kg) with mechanically assisted circulation for postcardiotomy cardiogenic shock. TEE provided valuable information: (1) dislocation of the cannula causing hemodynamic instability could be easily diagnosed and corrected; (2) Doppler evaluation of valvular function revealed severe malfunction in two patients; (3) intracardiac thrombus could be clearly detected in two children with seriously impaired hemodynamics. These findings were followed by therapeutic interventions; (4) left-ventricular function before attempted weaning from cardiac assist was moderately reduced or normal in the survivors, but poor in the nonsurvivors. We conclude that TEE is a valuable contribution to improved patient management during cardiac assist.

Child, Preschool↗
PubMed1994

Monitoring radio programs and time of day affect simulated car-driving performance.

Whether radio monitoring, task difficulty, and time of day affect driving performance was examined in a computer-controlled, simulated driving task. Driving performance was defined as the absolute deviation of the car position from road midline as displayed on the computer monitor. We found for 12 men and 8 women (i) an expected, marked deterioration of performance with increasing task difficulty, (ii) a deterioration of performance in the morning, and (iii) a deterioration of performance when subjects concurrently listened to radio programs except for the easy task conducted in the morning. The latter is supposed to be caused by a reactive increase of effort, which is induced by the concurrent radio monitoring and stimulated through a perceived impairment of attention.

Adult↗