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Biomedical subjects

S Schuster

Publications and source records attributed to S Schuster.

At least 91 records · Page 5Linked to original sources
PubMed1990

Dynamic exercise echocardiography of the left ventricle in physically trained children compared to untrained healthy children.

To evaluate the effect of physical training on left ventricular function, we investigated 52 children, aged 7 to 14 years, who had trained for endurance sports over a period of at least 1 year. The children (24 boys and 28 girls) were investigated echocardiographically during supine exercise on a bicycle at increasing work loads of 6, 9, 12 and 15 kpm/min/kg body weight. The parameters of left ventricular function (specifically fractional shortening and the velocity of circumferential fiber shortening; both these parameters corrected for heart rate) were evaluated before, during and after the test. The values obtained were compared to those in untrained children investigated in a previous study. Fractional shortening in trained children rose from 37 +/- 5% to 54 +/- 5%, and in untrained children from 37 +/- 4% to 46 +/- 4%. The velocity of fiber shortening in trained children rose from 1.27 to 3.15 circ/sec while in untrained children it increased from 1.25 to 2.53 circ/sec. Left ventricular contraction, therefore was significantly greater in trained than in untrained children during exercise. While untrained children increased their cardiac output in the first minutes of exercise mainly by elevating their heart rate, trained children increased simultaneously the stroke volume. There were no significant differences between boys and girls, or between stages of maturity. Thus, physical training causes quick adaptations of left ventricular function to exercise in children of all ages.

Adolescent↗
PubMed1990

Two distinct mutations at the same site in the PCCB gene in propionic acidemia.

Propionic acidemia is an inborn error of metabolism resulting from a deficiency of propionyl-CoA carboxylase activity. The alpha- and beta-subunits of the enzyme are encoded by the PCCA and PCCB genes, respectively. Using direct sequencing and restriction digests of amplified reverse transcripts and genomic DNA, we have identified two mutations of the PCCB gene in a propionic acidemia patient from the pccC complementation subgroup (the PCCB gene contains the major complementation group pccBC and subgroups pccB and pccC). One of the proband alleles contains an inframe 3-bp deletion inherited from the father which results in the deletion of an isoleucine residue in the beta-subunit of the enzyme. The other mutant allele, inherited from the mother, has a 14-bp deletion and an addition of 12 bp of new sequence at the same site as the father's allele. The inserted sequence is a partial duplication of a sequence just upstream of the mutation site. The net result of this mutation generates a frameshift and a downstream stop codon. Examination of fibroblast mRNA from the patient showed that it consists essentially of the father's sequence, making it effectively the only expressed allele for the beta-protein. A survey of additional patient cell lines revealed the insertion/deletion rearrangement in three additional patients, two from the pccBC group and one unclassified. The 3-bp deletion allele was unique to the proband. The identification of two distinct alleles occurring at the same site in the PCCB gene underscores the importance of this site in enzyme function or integrity.

Alleles↗
PubMed1990

Hemodynamics during PEEP ventilation in patients with severe left ventricular failure studied by transesophageal echocardiography.

The effects of mechanical ventilation with PEEP were investigated in five patients with normal cardiopulmonary function (group A) and in 11 patients with severe left ventricular failure (group B). Cross-sectional area of the right and left atrium (RA/LA), left ventricle (LV), and right ventricle (RV) was determined at EDA/ESA using transesophageal echocardiography. Hemodynamic parameters and transesophageal pressure were measured simultaneously at PEEP levels 0, 4, 8, 12, and 16 cm H2O. End-diastolic area of the right atrium decreased significantly in both groups. The RA pressure increased, while transmural pressure remained unaltered. The CI decreased in both groups. The decrease in cardiac output by PEEP ventilation was related to the decrease in RV filling volume by external compression. In patients with congestive heart failure, PEEP ventilation with 8 to 10 cm H2O did not worsen LV function.

Adult↗
PubMed1989

Fears of children and adolescents: a cross-sectional Australian study using the Revised-Fear Survey Schedule for Children.

The Revised-Fear Survey Schedule for Children was administered to over 3000 Australian youths, aged 8-16 yrs. Consistent with previous findings, there was a significant age-related decline in fears. Females reported significantly more fears than males. The most common fears were similar to those reported by children and adolescents in the U.S.A. Nuclear war was added to the stimulus items and found to be the most commonly endorsed fear. Thus the self-reports of fear showed a concern for physical danger and harm.

Adolescent↗
PubMed1989

[24-hour blood pressure behavior in patients with untreated and treated hypertension in comparison with normotensive patients].

Blood pressure was continuously monitored over 24 h in 201 patients with mild to moderate essential hypertension using a noninvasive method. Measurements were made both before and after 6 months of antihypertensive treatment and the data were compared to results from 100 normotensive patients. The frequency with which blood pressure values above 140/90 mm Hg occurred during the 24-h period proved to be the most reliable parameter for distinguishing between hypertensive and normotensive profiles. The blood pressures of all patients could be normalized (less than 140/90 mm Hg) on single or combined drug therapy as assessed by casual measurement. However, significant differences were observed between the 24-h profiles of the treated patients and the control group. The mean 24-h blood pressure, the mean day and nighttime blood pressures, the mean hourly pressure, and the frequency of increased blood pressure values were all significantly higher in the patients on medication as compared to the normotensive controls. This would suggest that normotension, as defined by the control group, cannot be attained with antihypertensive medication. In conclusion, 24-h continuous blood pressure monitoring allows a better evaluation of blood pressure profiles and consequently, will be of greater value in assessing cardiovascular risk than occasional random measurements.

Adult↗
PubMed1987

Time hierarchy in enzymatic reaction chains resulting from optimality principles.

Several optimality principles reasonable for the evolution of enzyme reaction chains are formulated, considering the kinetic parameters of the enzymes to be variables. The solutions of these parametric programming problems are studied for the case of linear kinetics and turn out to be not unique in every case. The investigations are confined to stationary states. The net flux through the chain is considered a fixed parameter. The optimality criteria concern the osmotic pressure caused by the intermediates, various relaxation times, largest time scale, and controllability. They all yield distinct time hierarchies. The influence of a constraint concerning the sum of intermediate concentrations is studied. Various combinations of the single criteria are treated as multiobjective programming problems.

Biological Evolution↗
PubMed1987

Successful post-bypass ventricular assist with a centrifugal pump.

A 56 year old male with massive anterior wall infarction and development of a large aneurysm underwent aneurysmectomy and aorto-coronary bypass grafting to the RCA. Preoperative ejection fraction was 20%, LVedP was 30 mm Hg. During induction of anesthesia the patient sustained ventricular fibrillation and was successfully resuscitated. With the patient in progressive cardiogenic shock the operation was performed under emergency conditions. Despite adequate myocardial protection and cross-clamp time as well as prolonged reperfusion and balloon counterpulsation the patient could not be weaned off cardiopulmonary bypass. In this situation a centrifugal pump system was connected between the left atrium and the ascending aorta. With a pump flow of 5 l/min the patient was taken off cardiopulmonary bypass. After 20 hours of extracorporeal support without anticoagulation the device could be removed: explantation of the IABP followed 48 hours later. The patient gradually recovered and finally was discharged home in fair condition.

Assisted Circulation↗
PubMed1987

[Diagnostic value of the transesophageal Doppler echocardiography].

Transesophageal echocardiography has been proven to be of particular value in all patients with transthoracic echocardiograms of low quality related to pulmonary emphysema, obesity and chest deformation as well as in intensive care unit patients. Similarly, transesophageal Doppler echocardiography is of particular value in all cases in which the transthoracic Doppler, due to methodological problems, is of limited value. Mitral regurgitation can be detected and quantified and flow direction described. Only in 12/25 patients with mild, 11/12 patients with moderate and 5/8 patients with severe insufficiency was regurgitation detected by transthoracic echocardiography as compared to transesophageal echocardiography with which the lesion was consistently detected. In two patients with severe and clinically-inapparent mitral regurgitation related to papillary muscle rupture, the diagnosis was established only by the transesophageal approach in an emergency situation. Atrial septal defects were detected in 8/15 patients and the size of the defect analyzed. With transesophageal Doppler echocardiography, the relation of left-to-right and right-to-left shunts could be described. In 7/16 patients with aortic dissection, true and false lumen were differentiated by analysing the flow pattern within both lumina. In 9/16 patients differentiation was enabled through delineation of the false lumen which was filled with thrombotic material. Detection of aortic regurgitation and tricuspidal regurgitation is possible but analysis of flow patterns is difficult because flow direction is nearly orthogonal to the ultrasound beam. First attempts to quantify cardiac output have been performed. For the future, transesophageal color flow Doppler mapping appears to be a most promising method.

Aortic Valve Insufficiency↗
PubMed1987

[Bacteremia caused by Lactobacillus plantarum in endocarditis lenta].

A report is presented on a 43-year-old patient with a subacute endocarditis due to an immunovasculitis and a bloodstream infection caused by Lactobacillus plantarum. The causative agent was isolated six times from blood cultures. L. plantarum was identified according to the standard methods in anaerobe diagnostics (biochemical reactions and gas chromatography). Twenty-two isolations of lactobacilli from bloodstream infection are described in the literature.

Adult↗
PubMed1986

[The effect of cortisone on the course of respiratory and clinical parameters in ventilator patients with imminent ARDS].

24 subjects in an intensive care unit with indication for mechanical ventilation with PEEP and predisposition for ARDS have been investigated. All patients received 2 g prednisolone 8 times over 48 hours. In group A (14 patients) this was administered within the first 24 hours of the beginning of the ventilation, and in group B (10 patients) at a later stage in the therapy. Severity of the disease was assessed by TISS, and, in addition to respiratory parameters, coagulation, thrombocytes, blood sugar, lactate and phosphate were determined. The data were evaluated by exploratory data analysis with box plots and median values. According to TISS, the two groups are comparable (group A 31.5 points, group B 31.3 points, age in group A 50.6 years, in group B 54.0 years). FiO2 rose from 0.44 to 0.82 in group B and in group A declined from 0.83 to 0.3 during receipt of PaO2 of more than 60 torr. EIP (endinspiratory pressure) rose from 28.7 cm H2O to 33.5 cm H2O in group B and fell from 29 to 26 cm H2O in group A. Compliance in group B fell and remained constant at over 48 ml/cm H2O in group A. PTT and TZ were normal in both groups, and Quick time values lower in group A than in group B. Thrombocytes fell to 63,000 in group B and rose to 201,000 in group A. Lactate, phosphate and leukocytes were unchanged in both groups. No cases of pulmonary infection were observed in either group. Mortality was 50% in group A and 80% in group B. Critical evaluation of the data from this retrospective study suggest a more favourable course, especially of the respiratory parameters, if a high dose of corticosteroids is administered at an early stage (group A).

Blood Coagulation↗