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Biomedical subjects

R Kraemer

Publications and source records attributed to R Kraemer.

At least 109 records · Page 6Linked to original sources
PubMed1986

Dopamine-beta-hydroxylase in patients with cystic fibrosis.

The enzymatic activity of plasma dopamine-beta-hydroxylase (DBH) was determined in 92 children/adolescents with cystic fibrosis, in 25 parents (heterozygotes) of these patients and in 68 healthy controls. Statistically significant (P less than 0.01) lower DBH levels were found in cystic fibrosis patients (17.9 +/- 1.4 mumol/min per 1, SEM) compared to the controls (25.5 +/- 2.1 mumol/min per 1). In 37 patients plasma norepinephrine and dopamine levels were compared to the enzymatic activity, no significant correlation between these variables being shown (r = -0.134 for norepinephrine; r = 0.159 for dopamine). However, due to the large variability of DBH within the groups and due to the lack of relationship of this enzymatic activity to plasma catecholamines, it is concluded that these differences may neither account for the observed elevation of plasma dopamine in cystic fibrosis patients (0.94-6.73 nmol/l vs. 0.01-0.986 nmol/l for controls) nor for their putative autonomic dysfunction.

Adolescent↗
PubMed1986

Intrapulmonary gas distribution in healthy children.

Distribution of ventilation was evaluated in 54 healthy children (24 boys and 30 girls), aged 7-16 years by multibreath nitrogen washout (MBNW) curves, from which the moment ratios (m1: m0, m2: m0), the lung clearance index, the Becklake index and the ventilatory efficiency index (E 90%) was computed. Functional residual capacity (FRC) was calculated from the washout curve and compared with the thoracic gas volume (TGV) plethysmographically determined, as well as with the FRC determined by helium dilution. The study shows that MBNW can easily be performed during spontaneous breathing in children and provides specific indices of ventilation. These indices show no sex difference and are age-independent. Therefore, the data of the present study contradict some previous indirect findings suggesting that the distribution of air in the lungs would become more even with age. There are in contrast more convincing direct measurement data showing that airways grow isotropically relative to the lungs.

Adolescent↗
PubMed1986

Antimicrobial therapy of Pseudomonas pulmonary exacerbations in cystic fibrosis. A prospective evaluation of netilmicin plus azlocillin versus netilmicin plus ticarcillin.

High-dose anti-Pseudomonas chemotherapy is mandatory in the treatment of acute pulmonary exacerbations in patients with advanced cystic fibrosis and Pseudomonas aeruginosa isolated from their sputum. However, neither the regimen itself nor its objective evaluation have been optimized yet. In a prospective controlled evaluation 42 such exacerbations were treated for two weeks with netilmicin combined by randomisation with either azlocillin or ticarcillin. Other aspects of therapy were constant. The two therapy groups were comparable in all aspects. Both regimens produced similar improvements in clinical, radiological, laboratory, bacteriological and pulmonary function measurements. Concentrations of sputum bacteria were significantly reduced; transient eradication was documented in 29% and correlated with antibiotic susceptibility of the initially isolated Pseudomonas strains. The highly dosed antibiotics were well tolerated and emergence of resistance was rarely observed. It is concluded that both antibiotic combinations are beneficial and safe in cystic fibrosis. Monitoring of such intensive hospital treatment must include multiple parameters.

Adolescent↗
PubMed1985

[Surgical treatment of portal hypertension in patients with cystic fibrosis].

Patients with cystic fibrosis involving the liver may develop esophageal varices with the risk of major bleeding. As the pulmonary disease is progressive, treatment of the varices should achieve definite protection from bleeding by portal decompression. In three 17-18 year-olds splenectomy with splenorenal anastomosis was carried out without mortality or relevant morbidity. Two patients had had previous episodes of bleeding. The patients were followed up for 15, 15 and 42 months respectively. The varices disappeared or regressed in size, and no bleeding or side effects of the shunt were observed.

Adolescent↗
PubMed1985

[Residual lung function changes following adult respiratory distress syndrome (ARDS) in children].

Residual lung function abnormalities have been investigated in 9 children (4 boys and 5 girls) a mean 2.7 years after surviving severe adult respiratory distress syndrome (ARDS). All patients had been artificially ventilated for an average of 9.4 days with a FiO2 greater than 0.5 for 34 hours and maximal PEEP levels in the range of 8-20 cm H2O. Since the ARDS, 3 children had presented recurrent respiratory symptoms (moderate exertional dyspnea and cough) and 2 had had evidence of fibrosis on chest radiographs. In all patients abnormal lung functions were found, i.e. ventilation inequalities (8), hypoxemia (7), and obstructive (2) and restrictive (1) lung disease. A significant correlation between respirator therapy and residual lung function was found (duration of FiO2 greater than 0.5 in hours and inspiratory plateau pressure during respirator therapy vs. ventilation inequalities and hypoxemia).

Adolescent↗
PubMed1985

Myeloperoxidase activity as a quantitative assessment of neutrophil infiltration into ischemic myocardium.

The infiltration of neutrophils into ischemic myocardium exacerbates myocardial damage upon reperfusion, whereas drugs that inhibit neutrophil activity or function reduce infarct size. Consequently, it is important to accurately assess the myocardial neutrophil content. Histologic sections and radiolabeled cells have been used, but have major limitations. We have developed a method to measure the neutrophils present in cardiac tissue by utilizing a spectrophotometric assay for the neutrophil-specific myeloperoxidase enzyme (MPO) (Bradley et al., 1982a). Coronary artery occlusion and reperfusion in the anesthetized dog induces neutrophil accumulation into the ischemic heart, which shows a linear relationship with time. An increase in activity from 0.014 +/- 0.001 units (u) MPO/100 mg tissue to 0.091 +/- 0.02 u MPO/100 mg is already apparent at the end of the 90-min occlusion period. This activity increases over 5 hr reperfusion to 0.32 +/- 0.018 u MPO/100 mg tissue. Histologic analyses confirmed the temporal association of neutrophil accumulation. Moreover, there is a correlation between infarct size and tissue MPO activity. Measuring the MPO content in preparations of canine neutrophils, which is directly correlated with cell number, allows units of MPO activity to be converted into a tissue neutrophil content. This assay is simple, sensitive, and provides a quantitative index of myocardial neutrophil accumulation that can be used to study the relationship between leukocyte infiltration and myocardial injury.

Animals↗
PubMed1985

Long-term sequelae in children surviving adult respiratory distress syndrome.

Nine children surviving severe adult respiratory distress syndrome were studied 0.9 to 4.2 years after the acute illness. They had received artificial ventilation for a mean of 9.4 days, with an Fio2 greater than 0.5 during a mean time of 34 hours and maximal positive end expiratory pressure levels in the range of 8 to 20 cm H2O. Three children had recurrent respiratory symptoms (moderate exertional dyspnea and cough), and two had evidence of fibrosis on chest radiographs. All patients had abnormal lung function; the most prominent findings were ventilation inequalities, as judged by real-time moment ratio analysis of multibreath nitrogen washout curves (abnormal in eight of nine patients) and hypoxemia (seven of nine). Lung volumes were less abnormal; one patient had restrictive and two had obstructive disease. A significant correlation between intensive care measures (Fio2 greater than 0.5 in hours and peak inspiratory plateau pressure) and lung function abnormalities (moment ratio analysis and hypoxemia) was found. A possibly increased susceptibility of the pediatric age group to the primary insult or respiratory therapy of adult respiratory distress syndrome is suggested.

Adolescent↗
PubMed1985

Fast real-time moment-ratio analysis of multibreath nitrogen washout in children.

To apply real-time moment-ratio analysis to multibreath N2-washout curves (MBNW) from children, a new processor-controlled device was constructed. Flow and fractional N2 concentration (FN2) were each sampled by 200 Hz. An electromagnetic triple-valve system, with an instrumental dead space of 36 ml and a valve resistance of 0.3 cmH2O . l-1 . s, was connected in series with a pneumotachograph and an N2 analyzer (Ohio 720) placed next to the mouthpiece. A FORTRAN/MACRO program on a PDP 11/23 computer enabled measurement of inspiratory and expiratory flow and FN2 sampling by a 12-bit analog-to-digital converter. The fast real-time digital processing of the N2 and flow signals incorporated filtering, delay compensation, and corrections for the effects of changes in gas composition and temperature. MBNW dynamics of the lungs were studied in 17 healthy and 28 asthmatic children and in 16 patients with cystic fibrosis, evaluating the moment ratios of the washout curves as indices of the ventilation characteristics. Intrasubject variability of the moment ratios (m1/m0, m2/m0) and determination of functional residual capacity (FRC) varied between 6.3 and 14.7% (depending on which parameter is considered) and was comparatively lower than other indices previously investigated in adults. In addition, the sensitivity of the moment ratios for discriminating different stages of ventilation inhomogeneity was superior to other indices. m2/m0 is closely related to the simultaneously measured airway resistance, and the ratio between cumulative expired volume and FRC is correlated with the ratio between residual volume and total lung capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Plasma and urinary catecholamines in patients with cystic fibrosis.

In 43 patients with cystic fibrosis (age 8-23 yr, 26 boys and 17 girls) attending a summer camp in a mountain rehabilitation center and in 25 parents (heterozygotes) plasma epinephrine, norepinephrine, dopamine and plasma activity of dopamine-beta-hydroxylase were determined as well as the 24-h excretion of the free urinary amines (epinephrine, norepinephrine, dopamine), their O-methylated products (metanephrine, normetanephrine, 3-methoxytyramine) and the urinary phenolic acids (vanilmandelic and homovanillic). Also the metabolic breakdown product of serotonin in urine, the 5-hydroxyindoleacetic acid, was determined. Significantly elevated plasma dopamine (0.03-0.45 nmol/liter for controls versus 1.70-2.21 nmol/liter for cystic fibrosis) and slightly higher plasma norepinephrine levels were found in patients with cystic fibrosis. An increased 5-hydroxyindoleacetic acid excretion was noticed in adolescent patients which correlated with the disease state and the extent of lung involvement. No abnormalities of plasma amine levels were seen in the parents of the patients. Despite controversial results, CF patients seem to have an alteration in catecholamine metabolism which is reflected in higher plasma dopamine levels.

Adolescent↗
PubMed1985

[Methods of detection of exercise-induced asthma].

Different forms of physical exertion induce different degrees of severity of exercise induced asthma. Standardized methods are needed to quantify this phenomenon. These methods should include the possibility to examine lung function more differentially, especially to modify the conditions of inhaling air. Free running is difficult to standardize as an exercise. Bicycle-ergometers provide the most reliable results, allowing for triangular or rectangular exercise. Results should be related to fat-free body weight.

Airway Resistance↗
PubMed1985

Serum selenium concentrations and glutathione peroxidase activities in cattle grazing forages of various selenium concentrations.

In cows from 15 dairy herds (n = 210), serum selenium (Se) concentrations ranged from 0.021 to 0.789 microgram/ml, whereas 0.05 to 0.40 microgram/ml is the reported range for adequate serum Se concentrations in cattle. Serum Se concentrations of dairy cattle appeared to follow a geographic distribution pattern. On the basis of herd mean serum Se concentrations, adequate serum Se concentrations were found in cattle from only 1 of 5 herds grazing forage in the geographic area classified as Se deficient for cattle. Adequate mean serum Se concentrations were found in cattle from 4 of 5 herds located in geographic areas described as having variable forage Se concentrations (Se-marginal areas). Of the 10 herds from these 2 areas, there were only 2 herds in which 95% of the cattle had serum Se concentrations in the Se-adequate range (0.05 to 0.40 microgram/ml). In 2 selected neighboring farms in the Se-deficient area, cattle in 1 herd had adequate serum Se concentrations and cattle in the other herd had less than adequate serum Se concentrations (less than 0.05 microgram/ml). Therefore, more cattle are at risk of developing Se-deficiency disease than is commonly believed and forage of neighboring farms may have different Se concentrations. Serum Se concentrations (up to 0.789 microgram/ml) correlated with glutathione peroxidase enzyme activity; this serum Se concentration (0.789 microgram/ml) is approximately 6.2 times higher than previously reported in dairy cattle. Therefore, RBC glutathione peroxidase activity may be useful in determining the diagnosis of chronic Se toxicosis.

Animal Feed↗