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J Meyer

Publications and source records attributed to J Meyer.

At least 253 records · Page 14Linked to original sources
PubMed1998

Arterio-venous carboxyhemoglobin difference suggests carbon monoxide production by human lungs.

Carbon monoxide is hypothesized to be produced by the enzyme heme oxygenase predominantly in liver and spleen, bound to hemoglobin, and excreted by the lungs. Thus, venous carboxyhemoglobin is expected to be higher or equal to arterial carboxyhemoglobin. Unspecific inflammatory stimuli have been shown to induce heme oxygenase in lung tissue possibly leading to pulmonary carbon monoxide production. Arterial and central venous carboxyhemoglobin levels were measured in critically ill patients on the third day of ICU stay (n = 59) as well as in otherwise healthy humans prior to orthopedic surgery (n = 29). Arterial and central venous carboxyhemoglobin were higher in ICU patients than in healthy humans, respectively. In both groups, arterial carboxyhemoglobin was significantly higher than central venous carboxyhemoglobin. The arteriovenous carboxyhemoglobin differences were similar in both groups. The data suggest (a) increased CO-generation in critical illness and (b) pulmonary CO-production in healthy and critically ill humans.

Arteries↗
PubMed1998

[Prevention of catheter-related infections, The official American guidelines--from the Centers for Disease Control].

The official German guidelines for prevention of intravascular-device-associated infections were published by the Bundes-gesundheitsamt, now called the Robert-Koch-Institut, 12 years ago. The recently published official "Guidelines for Prevention of Intravascular-Device Associated Infections" of the Centers for Disease Control and Prevention (CDC) are categorized according to scientific evidence. The American guidelines are very detailed and differ in some aspects from the official German guidelines. The purpose of the present paper is to inform the German-speaking anaesthesiologist about the official CDC guidelines and to provide an update on the prevention of intravascular-device-associated infections.

Catheterization↗
PubMed1998

[The official American guidelines for prevention of nosocomial pneumonia. U. S. Centers for Disease Control].

The official German guidelines for prevention of nosocomial pneumonia were published by the Bundesgesundheitsamt, now called Robert-Koch-Institut, twelve years ago. The recently published official "guidelines for prevention of nosocomial pneumonia" of the Centers for Disease Control and Prevention (CDC) are categorized according to scientific evidence. The American guidelines are very detailed and differ in some aspects from the official German guidelines. The purpose of the present paper is to inform the German anaesthesiologist about the official CDC guidelines and to provide a renewed background for the prevention of nosocomial pneumonia.

Cross Infection↗
PubMed1998

Comparison of the haemodynamic effects of nitric oxide synthase inhibition and nitric oxide scavenging in endotoxaemic sheep.

OBJECTIVE: The present study compared the effects of nitric oxide (NO) synthase inhibition and NO scavenging with haemoglobin in endotoxaemic sheep. DESIGN: 12 sheep were instrumented for chronic study. Six sheep received LG-nitro-arginine-methylester (L-NAME, 2.5 mg/kg bolus followed by a continuous infusion of 0.5 mg/kg per h), the other 6 sheep received pyridoxalated haemoglobin polyoxyethylene conjugate (PHP, 100 mg/kg bolus followed by a continuous infusion of 20 mg/kg per h). MEASUREMENTS AND RESULTS: Haemodynamic and oxygenation parameters were measured in healthy sheep, after infusion of Salmonella typhosa endotoxin (10 ng/kg per min) for 24 h and after infusion of L-NAME or PHP. The infusion of endotoxin resulted in a hypotensive, hyperdynamic circulation. Infusion of L-NAME increased mean arterial pressure (MAP) from 76.1 +/- 4.2 mmHg to normal values of 95.8 +/- 5.7 mmHg (p < 0.05). PHP increased MAP from 73.0 +/- 3.0 to 88.6 +/- 4.7 mmHg (p < 0.05). This increase in MAP was associated in the L-NAME group with a more prominent drop in cardiac index (from 10.2 +/- 0.4 to 7.0 +/- 0.51.min-1.m-2; p < 0.05) than in the PHP group (from 10.7 +/- 0.2 to 9.3 +/- 0.61.min-1.m-2). During the first 90 min of infusion, cardiac index remained lower in the L-NAME group than in the PHP group. The increase in pulmonary vascular resistance was also higher in the L-NAME group. CONCLUSION: These results suggest, that at the doses used in the experiment, NO scavenging with PHP has smaller effects on cardiac index and pulmonary vascular resistance than NO synthase inhibition with L-NAME. Therefore, the concept of NO scavenging in hyperdynamic sepsis should be further evaluated.

Animals↗
PubMed1998

Detection of coronary artery calcifications predicting coronary heart disease: comparison of fluoroscopy and spiral CT.

The aim of this study was to evaluate the clinical relevance of coronary artery calcifications detected by spiral CT, congruence with fluoroscopy (FS) and coronary angiography, and comparison with studies reporting on application of double-helical CT and ultrafast CT. Forty patients underwent spiral CT (2-mm slice thickness, table feed 3 mm/s), coronary angiography, and FS (performed in the usual manner). Stenosis and calcifications were evaluated semiquantitatively. Nineteen patients suffering from a stenosis >/= 75 % were verified at coronary angiography. All had coronary artery calcification on spiral CT. Fluoroscopy did not detect 8 of 19 patients with a stenosis >/= 75 % (1 vessel: n = 1; 2 vessels: n = 3; 3 vessels: n = 4). In spiral CT sensitivity was 100 % and specificity was 33 % (FS: 58 and 48 %). Positive predictive value was 83 % for spiral CT (FS: 50 %), and negative predictive value was 100 % (FS: 56 %). A significant linear increase in the calcification score was found for increasing maximal stenosis (p < 0.005). Spiral CT is more sensitive than FS in the recognition of hemodynamic relevant stenoses using the detection of coronary artery calcifications. Statistical parameters are comparable to ultrafast-CT. Spiral CT is a suitable non-invasive diagnostic technique in coronary heart disease. Coronary calcifications found incidentally in symptomatic patients at chest CT should be reported to the referring physician for further cardiological workup.

Adult↗
PubMed1998

[Prognostic significance of analysis of heart rate variability inpatients with dilated cardiomyopathy].

UNLABELLED: Sudden cardiac death is frequent in patients with dilated cardiomyopathy. To assess the risk of an arrhythmic event is still difficult. Here the analysis of the heart rate variability offers new possibilities. METHOD: 25 patients (18 males, 7 females, age 53 +/- 9 yrs) with dilated cardiomyopathy were included in the study. Analysis of heart rate variability assessed by time- and frequency-domain measures was determined from Holter recording. The mean follow-up was 18 +/- 5 months. RESULTS: 6 patients died (5 of sudden cardiac death, 1 of heart failure), 1 patient with an implanted defibrillator received an adequate shock. Parameters influenced by low- and mid-frequent oscillations of the heart rate were significantly lower in patients who died suddenly or had adequate shocks. The best predictive parameter was the s.d.RR: all patients with an s.d.RR < 50 ms had lethal arrhythmias whereas the s.d.RR of the surviving patients was > or = 50 ms. No significant difference was found or high frequency parameters, which are mainly influenced by parasympathetic activity. CONCLUSION: The analysis of heart rate variability is of prognostic relevance in patients with dilated cardiomyopathy. Especially the s.d.RR is able to identify patients with a high risk of a sudden cardiac death.

Adult↗
PubMed1998

[Acute vascular perforation with shunt formation in the right ventricle after percutaneous transluminal coronary angioplasty. Magnetic resonance tomography and Doppler ultrasound detection of shunt flow].

A coronary artery perforation is a rare complication after percutaneous transluminal coronary angioplasty. The therapy will be determined by the hemodynamic failure of the left or right ventricle. A case of a coronary artery perforation with a shunt from the right coronary artery to the right ventricle after coronary angioplasty is reported. The shunt was detected by coronary angiography and confirmed by magnetic resonance imaging and doppler echocardiography.

Aged↗
PubMed1998

[Hemodynamic effects of a single intravenous administration of prostaglandin E1 in a patient sample with chronic NYHA-stage II/III heart failure].

We investigated the hemodynamic effects of a single infusion of PGE1 (60 micrograms infused over a period of 2 h--this is the single dose used in courses of treatment for peripheral occlusive arterial disease) in patients with chronic heart failure NYHA class II-III. The ejection fraction of these patients was < 55%, their average age was 58.4 years (standard deviation 10 years), and their condition was stable. Nineteen of the patients had coronary heart disease and one patient had myocarditis. The hemodynamic data were obtained invasively by catheterization of the right and left heart. Blood pressure and pulse rate were measured manually. Intravenous infusion of 60 micrograms PGE1 over a period of 2 hours did not significantly alter contractility or hemodynamics. Dp/dtmax, dp/dtmax/p, and dp/dt DP40, which are parameters of left ventricular contractility, determined with the aid of a catheter-tip manometer, did not differ significantly over time from those in the placebo control group. Similarly, the other data furnished no evidence that administration of PGE1 had any hemodynamic or myocardial effects. Hence, it is reasonable to state that it is safe to administer PGE1 to patients with peripheral occlusive arterial disease.

Adult↗
PubMed1998

DNA analysis of temperate bacteriophage Aa(phi)23 isolated from actinobacillus actinomycetemcomitans.

The DNA of the temperate bacteriophage Aaphi23 isolated from the oral bacterium Actinobacillus actinomycetemcomitans was examined structurally both in the phage head and in the prophage. The DNA in phage particles comprises 44 kb linear molecules with a terminal redundancy of 1.6 kb, which represent circular permutations. Thus, DNA is packaged into phage heads by the headful mechanism. The Aaphi23 prophage is integrated into the host chromosome.

Aggregatibacter actinomycetemcomitans↗
PubMed1998

Cloning and functional characterization of the human norepinephrine transporter gene promoter.

The norepinephrine transporter (NET) plays a critical role in brain norepinephrine homeostasis and is a target for antidepressants and drugs of abuse. We have analyzed the 5'-flanking regulatory region of the human NET gene (SLC6A2). Primer extension and 5' RACE revealed a single transcription start site, alternative splicing of exon 1 due to alternate splice donor usage, and a variable splice acceptor of intron 1. A TA-rich motif 35 bp upstream of the transcription start and several potential binding sites for transcription factors including a cAMP response element (CRE)-like motif are present in the 5'-flanking region. A 4.0-kb fragment, which had been fused to the luciferase reporter gene and transiently expressed in a NET+ cell line, displayed both constitutive and inducible promoter activity. Functional analysis by serial deletions revealed several clusters of cell-selective enhancer elements. Our findings indicate that (1) the NET gene promoter is active in NET-expressing cells and the information contained within approximately 4 kb of the 5'-flanking sequence is required to confer its cell-selective expression, (2) the expression of NET is regulated by a combination of positive cis-acting elements operating through a basal promoter defined by a TA-rich motif, and (3) the promoter responds to cAMP-dependent induction. Fusion of the human NET gene promoter to selected genes will facilitate their cell-selective expression in gene transfer strategies.

Animals↗
PubMed1998

Impact of routine angiographic follow-up after angioplasty.

BACKGROUND: There is an ongoing controversy as to whether repeat coronary angiography should be routinely performed after successful percutaneous transluminal coronary angioplasty (PTCA). METHODS: We examined the 10-year outcome in 400 patients who had or had not undergone an angiographic control 6 months after successful PTCA and a subsequent event-free 6-month period. Our comparison was based on data gathered by questionnaire and telephone interview in 315 patients with (group A) and 85 patients without (group B) a routine 6-month angiographic control. Multivariate analysis (Cox model) was performed to identify predictors of adverse events. RESULTS: During the 10-year follow-up period, 22 (7%) of the 315 patients in group A died, compared with 16 (19%) patients in group B (P= .003). In groups A and B, respectively, acute myocardial infarction occurred in 28 (9%) and 10 (12%) patients (not significant [NS]); coronary artery bypass grafting (CABG) was performed in 42 (13%) and 14 (16%) patients (NS); repeat PTCA was performed in 89 (28%) and 11 (13%) patients (P= .012); and serious adverse events (death, myocardial infarction, CABG) occurred in 76 (24%) and 32 (38%) patients (P= .02). Absence of a 6-month angiographic follow-up was identified as an independent predictor of death associated with a 2.7 times higher mortality rate during the 10-year follow-up period. Previous myocardial infarction increased the risk of death 2.5 times. Any increase of residual diameter stenosis by 10% was combined with a 1.4 times higher mortality rate. The chance of bypass surgery was higher in patients with multivessel disease (2.9 times), in patients with unstable angina (2.1 times), and in case of an increase of residual diameter stenosis by 10% (1.3 times). No predictor for the risk of myocardial infarction was found. Angiographic follow-up increased the likelihood of PTCA 2.5 times. CONCLUSIONS: A routinely performed angiographic control 6 months after successful PTCA is associated with a significantly higher rate of repeat PTCA but, most important, is correlated with a significantly lower mortality rate during the 10-year follow-up period.

Adult↗
PubMed1998

Effect of liver impairment on the pharmacokinetics of tolcapone and its metabolites.

OBJECTIVE: To assess the effect of liver impairment on the pharmacokinetics of tolcapone and to derive appropriate dose recommendations for patients with this disease who are undergoing treatment for Parkinson's disease. STUDY DESIGN: In an open, two-way crossover study, 16 patients with moderate liver disease (eight with cirrhotic and eight with noncirrhotic liver disease) and eight healthy subjects received an oral dose of 200 mg tolcapone and an intravenous dose of 50 mg tolcapone on separate occasions. The concentrations of total and unbound tolcapone and its three major metabolites (tolcapone glucuronide, carboxylic acid, and 3-O-methyl metabolite) were assessed in plasma and urine. RESULTS: On the basis of total drug concentration, the differences in tolcapone pharmacokinetics between the groups were small. However, lower clearance and volume of distribution of unbound drug were found among patients with cirrhosis than among control subjects. Plasma concentration of the pharmacologically inactive glucuronide metabolite was increased among patients with cirrhosis. CONCLUSIONS: Half of the recommended dosage of tolcapone should be administered to patients with cirrhosis of the liver to maintain the target steady-state concentration of unbound drug and to avoid accumulation of tolcapone glucuronide. Our data did not indicate a requirement for dosage adjustment in the presence of moderate chronic hepatitis.

Adult↗
PubMed1998

Work organization and atherosclerosis: findings from the ARIC study. Atherosclerosis Risk in Communities.

INTRODUCTION: The aim of this investigation was to examine the extent to which work organization (i.e., occupational stress) is associated with subclinical carotid atherosclerosis. METHODS: For that purpose we used a cross-sectional study of four U.S. community samples conducted between 1987 and 1989. Participants in the study were 10,801 adults aged 45 to 64 years. Subclinical carotid atherosclerosis was assessed by measuring the intima-media thickness (IMT) of the carotid artery wall using B-mode ultrasound. Occupational stress was defined using six indicators: substantive complexity of work, physical demands, job insecurity, skill discretion, decision authority, and physical exertion. Information from U.S. national surveys on occupational stress indicators was linked to the study participants' occupation. RESULTS: We observed negative associations of complexity of work and skill discretion with mean IMT of the carotid artery wall among the four race-gender groups. In addition, physical demands was positively associated with mean IMT among blacks and job insecurity was positively associated with IMT among white women and black men. After adjustment for well-established risk factors, the magnitude of these associations was substantially reduced. CONCLUSIONS: Taken in combination with results from recent European studies, our findings suggest that work organization plays a role in the etiology of atherosclerosis.

Adult↗
PubMed1998

Transesophageal ultrasonographic imaging in rat hearts: visualization of aortic valve vegetations in non-bacterial thrombotic endocarditis.

The aim of this study was to test the feasibility of transesophageal ultrasonography in rats by using an intravascular ultrasound system for visualization of vegetations at the aortic valve in the animal model of experimental endocarditis. After anesthesia and preparation of the right carotid artery, a polyethylene catheter was advanced across the aortic valve into the left ventricle in 91 rats. For transesophageal ultrasonography an intravascular ultrasound catheter (3.5 French; 30 MHz) linked to an imaging system was introduced into the esophagus. Sonographic investigations were performed every 24 hours until death. The presence, size, and echogenicity of vegetations were evaluated. Presence and size were compared to autopsy findings. No complications occurred as a result of the sonographic investigation. Left-sided valvular structures were imaged regularly. For detection of vegetations, sensitivity and specificity were 93% and 88%, respectively. Comparing the measurements of the vegetation size the following regression equation was obtained: y = 0.74x + 0.04 (r = 0.89; standard error of estimate = 0.02 cm). Inter- and intraobserver variabilities for sonographic measurements were 8.3% and 6.2%, respectively. Transesophageal ultrasonography permits reliable detection and repetitive accurate quantification of vegetations in the rat model of endocarditis. The technique enhances longitudinal studies of the dynamic process of the growth of vegetations under defined microbial conditions.

Animals↗
PubMed1998

Animal pharmacokinetics and interspecies scaling of Ro 25-6833 and related (lactamylvinyl)cephalosporins.

From a series of six (lactamylvinyl)cephalosporins, candidates for clinical evaluation were selected on the basis of their kinetic profile in animals and predicted pharmacokinetics in man. Exploratory pharmacokinetic studies with Ro 25-6833 and five related cephalosporins were performed following intravenous administration to rats, dogs, and cynomolgus monkeys. All compounds were characterized by a high protein binding in rat, monkey, and human plasma (unbound fraction < or = 5%), whereas in dog plasma, protein binding was markedly lower. Accordingly, for most compounds, clearance was highest in dogs, and lowest in monkeys. Comparison of the renal clearance of unbound drug with creatinine clearance suggests a renal elimination of Ro 25-6833 by glomerular filtration in both rats and dogs (urinary excretion in monkey was not determined due to drug instability in monkey urine). All other compounds showed different renal excretion mechanisms in rats and dogs, thus making the validity of allometric scaling questionable. Unbound clearances in man were predicted by allometric scaling (Ro 25-6833 only) and by a correlation analysis of cephalosporin pharmacokinetics in monkey and man. Limitations of both methods are discussed. When Ro 25-6833 was later studied in man, the predicted pharmacokinetic data in man from both approaches were found to be in good agreement with the observed values.

Animals↗
PubMed1998

In vitro examination of the coronary artery wall after balloon angioplasty using intracoronary ultrasound.

After autopsy 12 human coronary arteries were investigated by intracoronary ultrasound in order to measure the vessel wall dimensions and to detect damage on the vessel wall architecture after balloon angioplasty. Histology revealed artherosclerosis in 11/12 arteries. A total of 41 representative coronary segments were selected for further off-line ultrasound and histological analysis. Intracoronary ultrasound and histological measurements of the vessel wall thickness after balloon dilatation demonstrated a good correlation between the maximum thickness of the intima (histology 0.62 mm vs. intracoronary ultrasound 0.65 mm, r = 0.87) and the intima-media complex (0.80 mm vs. 0.83 mm, r = 0.87), in contrast to a weak one between the minimum thickness (r = 0.46 and r = 0.37). A total of 21 cases of damage occurred during angioplasty; intracoronary ultrasound detected 17. Further analysis showed that it imaged 10 of 11 cases of damage involving more than 30 degrees of the vessel circumference and 7 of 10 cases of damage involving less than 30 degrees of the vessel circumference. After balloon angioplasty of diseased coronary arteries, intracoronary ultrasound is therefore reliable in measuring the maximum wall thickness and in imaging damage involving more than 30 degrees of the vessel wall circumference.

Angioplasty, Balloon↗