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Biomedical subjects

D Jung

Publications and source records attributed to D Jung.

At least 181 records · Page 10Linked to original sources
PubMed1975

New Colorimetric reaction for end-point, continuous-flow, and kinetic measurement of urea.

A reaction of urea, o-phthalaldehyde and N-(1-naphthyl)ethylenediamine is described for measurement of urea by manual, continuous-flow, and kinetic methods. The continuous-flow system requires 25 mu-l of sample; 40 samples can be analyzed per hour. The kinetic method requires no enzymes, has no lag phase, and has good sensitivity. A major advantage of the reaction is that it occurs at a temperature of 37 degrees C or lower. The results obtained by all three methods agree well with those for a continuous-flow procedure in which diacetyl is a reagent.

Aldehydes↗
PubMed1975

[Circulation and anesthesia].

In this paper a survey is given on the group of risk in patients with diseases of the circulatory system under the stress of anaesthesia with special regard to arterial hypertension, chronic ischaemic heart disease, disturbances of cardiac rhythm and global heart insufficiency besides the generally acknowledged therapeutic principles for cardiological patients of risk. On the conditions of a surgical intervention the author adopts a definite attitude to the partly still contrary problems of the preoperative antihypertensive treatment and to the prophylactic therapy with glycosides. The most important diagnostic and therapeutic facts concerning the necessary interdisciplinary cooperation between internist, anaesthesist and operator in preparation and performance of an operative intervention in patients with circulatory diseases are described.

Anesthesia, General↗
PubMedDate not supplied

Pharmacokinetics of theophylline in protein-calorie malnutrition.

The influence of protein-calorie malnutrition (PCM) on the disposition of theophylline was investigated in male Sprague-Dawley rats fed for four weeks on a 23 per cent (control) or 5 per cent (low) protein diet ad lib. Dietary protein deficiency led to a decrease in body weight gain, plasma proteins, albumin, microsomal proteins, and cytochrome P-450. After intravenous administration of aminophylline equivalent to 10 mg kg-1 theophylline, the average mean residence time (MRT) was 58 per cent higher in the protein-deficient rats, while the total plasma clearance (Cl) per kilogram of body weight and elimination rate constant (k) were decreased by 39 per cent and 45 per cent, respectively, when compared to rats on a normal protein diet. No significant difference was found in the two groups of animals with respect to the apparent steady-state volume of distribution (Vss). The present results suggest that the mechanism responsible for the observed pharmacokinetic changes in the protein-deficient rats is related to the reduced amount and/or activity of the hepatic mixed function oxidases.

Animals↗
PubMedDate not supplied

Absorption and disposition kinetics of chlorothiazide in protein-calorie malnutrition.

The influence of dietary protein deficiency on the absorption and disposition kinetics of chlorothiazide was investigated in male Sprague-Dawley rats fed for 4 weeks on a 23 per cent (control) or a 5 per cent (low) protein diet ad libitum. Chlorothiazide in plasma and urine was determined by a sensitive and specific HPLC assay. Following an intravenous dose of 10 mg kg-1 chlorothiazide, there was a significant decrease in the total plasma clearance (Cl) per kg of body weight from 1.80 +/- 0.15 to 1.29 +/- 0.15 l h-1 kg-1 and apparent steady-state volume of distribution from 0.65 +/- 0.13 to 0.38 +/- 0.07 l kg-1 in the protein-deficient rats. However, no significant difference was found in the two groups of animals with respect to mean residence time (MRT) and free fraction of drug in plasma. The mean harmonic half-life was increased from 72 to 91 min in the protein-deficient rats. The urinary recovery of unchanged chlorothiazide in 48 h was essentially complete in both groups of animals. The absorption of chlorothiazide, as assessed by the mean urinary recovery of unchanged drug after oral administration, was 66 per cent and 68 per cent in normal and protein-deficient rats, respectively.

Animals↗
PubMedDate not supplied

Effect of acute water deprivation on renal function in rats.

The effect of acute water deprivation for 96 h on renal function was studied in male Sprague-Dawley rats. The glomerular filtration rate (GFR) and the effective renal plasma flow (ERPF) were estimated using inulin and p-amino hippuric acid (PAH), respectively, as model compounds. Acute water deprivation caused a significant decrease (44 per cent) in the GFR without altering the ERPF. These results indicate that a proper dosage adjustment may have to be made in the dehydration condition, especially for drugs whose disposition is dependent on GFR.

Animals↗
PubMedDate not supplied

Effects of single large doses of phenytoin on glucose homeostasis--a preliminary report.

The effects of a loading dose of 15 mg/kg phenytoin by iv infusion on the serum levels of insulin, glucagon, and glucose were investigated in five fasting healthy male volunteers between the ages of 23 and 35 years. Serum glucose concentrations rose immediately after the infusion of phenytoin followed by a significant increase in serum insulin values (P less than 0.05). A slight elevation in mean glucagon concentrations after the infusion was not statistically significant. Further studies are indicated to determine whether phenytoin as used in the treatment of status epilepticus may aggravate the hyperglycemia associated with seizures.

Adult↗
PubMedDate not supplied

Ganciclovir absolute bioavailability and steady-state pharmacokinetics after oral administration of two 3000-mg/d dosing regimens in human immunodeficiency virus- and cytomegalovirus-seropositive patients.

Oral ganciclovir has recently been approved for use in long-term maintenance therapy in the treatment of cytomegalovirus (CMV) retinitis in immunocompromised patients. Although oral ganciclovir at a dose of 3,000 mg/d is moderately less effective than intravenous (i.v.) ganciclovir maintenance therapy (5 mg/kg as a 1-hour i.v. infusion every 24 hours), convenience and practicality make oral maintenance therapy desirable. Two dosing regimens--1,000 mg three times daily (TID) and 500 mg every 3 hours (six times daily)--have been shown to be efficacious. Eighteen human immunodeficiency virus- and CMV-seropositive patients participated in a three-way, open-label, crossover study to evaluate the steady-state pharmacokinetics and absolute bioavailability of the two oral regimens compared with the i.v. regimen. Sixteen patients completed the study and received ganciclovir as a single 5-mg/kg i.v. infusion over 1 hour, 500 mg orally every 3 hours while awake (six times daily) for 3 days, and 1,000 mg TID orally for 3 days. Blood samples were obtained over a 24-hour period after the single i.v. dose and on day 3 of the oral dosing regimens. Mean peak serum concentrations were 8.27, 1.02, and 1.18 micrograms/mL for the i.v. and oral regimens, respectively. Twenty-four-hour area under the curve (AUC) for the oral regimens--500 mg every 3 hours and 1,000 mg TID--were 15.9 and 15.4 micrograms.h/mL, respectively, as compared with a total AUC of 22.1 micrograms.h/mL for the single i.v. dose. The absolute bioavailabilities for the two oral regimens were 8.84% and 8.53%, respectively. The extent of ganciclovir absorption, peak concentrations, and average concentration at steady state were not statistically different between the two oral regimens. The peak-to-trough concentration ratio (Cmax:Cmin) was greater for the 1,000-mg TID regimen than for the regimen of 500 mg every 3 hours (5.35 vs 3.81 [P < 0.01]). Both oral regimens resulted in concentrations in the range of the concentration that inhibits 50% of most human CMV isolates. Because both oral regimens provide equivalent absorption, the 1,000-mg TID regimen may be preferred for the convenience and potentially greater compliance associated with fewer daily doses.

Administration, Oral↗
PubMedDate not supplied

Characterization and subcellular localization of the dystrophin-protein 71 (Dp71) from brain.

In the present study, monoclonal antibodies raised against the C-terminal domain of dystrophin were used to identify and characterize Dp71 from the central nervous system. It was observed that the expression of Dp71 gradually increases from the embryo stage until the adult. Subcellular distribution analysis indicates that Dp71 is mainly recovered in synaptic plasma membranes, microsomes and at a lesser extent in synaptic vesicles and mitochondria. The amino acid composition and N-terminal sequence of bovine brain Dp71 were determined. Moreover, we found that this protein is glycosylated.

Animals↗
PubMedDate not supplied

Effects of high doses of toluene on color vision.

High exposure to toluene may cause optic neuropathy and retinopathy, both associated with dyschromatopsia. Another solvent, ethanol, is known to induce acute blue-yellow dyschromatopsia. This study investigated the acute effects of high doses of toluene on color vision. Eight male printshop workers were examined before and after cleaning printing containers with pure toluene. After cleaning, concentrations of toluene in blood were between 3.61 and 7.37 mg/l. Color vision was tested with the Farnsworth panel D-15 test, the Lanthony desaturated panel D-15 test, and the Standard Pseudoisochromatic Plates part 2. For control of possible acute effects, eight workers of a metal-working factory without any neurotoxic exposure were tested according to the same procedure. Acute exposure to toluene did not cause impairment of color vision. However, statistical power is limited due to the small number of exposed subjects. Color vision of the printshop workers tested before cleaning was slightly impaired (statistically not significant) when compared with unexposed subjects.

Adult↗
PubMedDate not supplied

A systematic review of risk factors associated with near-fatal and fatal asthma.

BACKGROUND: Asthma mortality and morbidity continue to be a serious global problem. Systematic reviews provide an opportunity to review risk factors in detail. OBJECTIVE: To review all of the literature for risk factors associated with near-fatal asthma (NFA) and fatal asthma (FA). METHODS: A literature search from 1960 to January 2004 in MEDLINE and EMBASE was conducted. Studies were included based on the following criteria: NFA was defined as an asthma exacerbation resulting in respiratory arrest requiring mechanical ventilation or a partial pressure of CO2 of at least 45 mmHg or asthma resulting in death (FA); the study reported the number of cases (NFA and/or FA) and asthmatic controls; there was explicit reporting of risk factors; cases that were adult and pediatric in nature; and all study types. Studies that included patients with chronic obstructive pulmonary disease were excluded. RESULTS: Four hundred and three articles were identified, of which 27 met the inclusion criteria. Increased use of medications such as beta-agonists via metered dose inhalers (OR=1.67, 95% CI 0.99 to 2.84, P=0.057) and nebulizers (OR=2.45, 95% CI 1.52 to 3.93, P=0.0002), oral steroids (OR=2.71, 95% CI 1.34 to 5.51, P=0.006) and oral theophylline (OR=2.02, 95% CI 1.03 to 3.98, P=0.04) and a history of hospital (OR=2.62, 95% CI 1.04 to 6.58, P=0.04) and/or intensive care unit (OR=5.14, 95% CI 1.91 to 13.86, P=0.001) admissions and mechanical ventilation (OR=6.69, 95% CI 2.80 to 15.97, P=0.0001) due to asthma were predictors of NFA and FA. Prior emergency department assessment did not confer a greater risk of NFA and FA (OR=1.13, 95% CI 0.43 to 2.92, P=0.810). The use of inhaled corticosteroids (ICS) measured in a dose-independent fashion (did the patient take ICS previously; yes or no) inferred equivocal risk of NFA and FA (OR=1.31, 95% CI 0.83 to 2.05, P=0.25). However, two studies measured the use of ICS in a dose-dependent fashion (ie, measured the number of prescriptions filled within the previous six to 12 months). Both studies showed a trend toward a protective effect against FA. One study showed that the premature cessation of ICS can hasten death. CONCLUSIONS: In the present study, risk factors of NFA and FA have been more accurately defined. Clinicians should identify patients with these characteristics to reduce their risk of NFA and FA. Further research should focus on quantifying the impact of risk factors on asthma deaths.

Adrenergic beta-Agonists↗
PubMedDate not supplied

Assessment of hypothalamic-pituitary-adrenocortical axis function in dexamethasone treated very low birth weight infants by a single dose metyrapone test and gas chromatographic mass spectrometric determination of urinary steroids.

In order to assess hypothalamic-pituitary-adrenocortical axis function, we conducted low and single oral dose metyrapone tests (35 mg/kg) in dexamethasone treated very low birth weight infants with bronchopulmonary dysplasia (n = 12). The responses to metyrapone of tetrahydro-11-deoxycortisol (THS) and cortisol metabolites were analyzed by gas chromatography and mass spectrometry in 24-h urinary specimens. For comparative reasons, morning plasma 11-deoxy-cortisol and cortisol were measured by radioimmunoassay before and after metyrapone. No side effects of metyrapone were observed in our patients. In 5 of 12 patients, no urinary THS could be stimulated after metyrapone and most of the other patients had small increases in urinary THS. These findings suggest suppressed or strongly impaired hypothalamic-pituitary-adrenocortical axis function in most patients. While the concentrations of plasma 11-deoxycortisol showed little variation, those of plasma cortisol were grossly different from the respective urinary values. We recommend steroid analysis in 24-h urinary specimens by gas chromatography and mass spectrometry, because urinary steroids provide more information and the highly specific analytical technique is independent of phenomena such as cross reactivity or matrix effects. The low and single oral dose metyrapone test in combination with urinary steroid analysis by gas chromatography and mass spectrometry therefore provides a noninvasive, convenient and safe means of evaluating the integrity of the hypothalamic-pituitary-adrenocortical axis in very low birth weight infants.

Adrenal Cortex↗