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Biomedical subjects

J Breuer

Publications and source records attributed to J Breuer.

At least 127 records · Page 7Linked to original sources
PubMed1989

Experimental ductus arteriosus: the relationships of atrial pressure, dilatation and flow with ANF secretion.

The design of the study was to determine whether an increased blood flow as seen in shunt lesions could serve as a stimulus for the secretion of atrial natriuretic factor (ANF). Since atrial pressure, flow, and dilatation are closely related, an experimental ductus arteriosus model was utilized, in which acute changes of flow are assumed not to dilate the left atrium. In six dogs, a Dacron graft was constructed between the main pulmonary artery and the innominate artery. Constricting and releasing the tape around the graft adjusted the amount of "ductal" shunting. The total pulmonary flow and the shunt flow were measured by electromagnetic-flow transducers around the aortic root and around the graft. Plasma ANF concentration was measured from both cardiac atria. The size of the left atrium was determined from echocardiographic measurements made from a short-axis view. The total pulmonary flow varied between 1.2 and 5.8 1/min. The highest measured ANF was 396 pg/ml, and this was from the left atrium when the pressure was 18 mmHg, the highest left atrial pressure recorded. The highest right atrial pressure (5 mmHg) also correlated with the highest right-atrial level of ANF (366 pg/ml). The right atrial pressure had a significant correlation with plasma ANF concentration (R = 0.43, p less than 0.05). Pulmonary flow and plasma ANF concentration did not correlate; neither did left atrial size and ANF levels in 16 flow states where the size was measured. In the absence of atrial dilatation there was minimal stimulus for ANF secretion. A transient increase of left atrial pressure, without a concomitant significant atrial dilatation, did not serve as a significant stimulus for ANF secretion.

Animals↗
PubMed1989

Cardiac function, substrate utilization, and myocardial energy metabolism studied with 31-P NMR spectroscopy during acute hypoglycemia and hyperketonemia.

Whether severe hypoglycemia alone or in combination with hyperketonemia might cause deterioration of cardiac function has been controversial. Therefore, the influence of acute hypoglycemia (mean 33 mg/dL) with and without hyperketonemia (mean 1.3 and 3.3 mM) on cardiac function, substrate utilization, and myocardial high energy phosphate levels was studied in 10 mongrel dogs. After 45 min of hypoglycemia, mean aortic pressure, total peripheral resistance, and myocardial oxygen consumption had increased significantly, but other hemodynamic parameters and regional myocardial function had not changed. Additional infusion of 3-hydroxybutyrate did not affect hemodynamic variables significantly. During both metabolic interventions in vivo phosphorus-31 nuclear magnetic resonance spectroscopy showed stable levels of myocardial phosphocreatinine, ATP, as well as the phosphocreatinine/ATP (3.0-3.2) ratio. Biochemical measurements revealed that hyperketonemia led to significant alterations in arterial concentrations and arteriocoronary venous differences of selected citric acid cycle intermediates, thus confirming previous reports which suggested a blockade of the 2-oxoglutarate-dehydrogenase reaction induced by ketone body oxidation. However, despite this blockade, the energy supply to the heart was not impaired as shown by normal nuclear magnetic resonance spectroscopy and cardiac performance. It is speculated, that the blockade might be due to an enhanced NADH/NAD ratio.

Adenosine Triphosphate↗
PubMed1989

Comparison of three methods for the determination of serum alpha-1-antitrypsin in patients with pulmonary diseases.

In patients with pulmonary diseases, serum alpha 1-antitrypsin (AAT) was measured by three methods: radial immunodiffusion (RID), trypsin inhibitory capacity assay (TIC) and by rate nephelometry with the immunosystem (NIA) in a total of 369 subjects (sarcoidosis, n = 35; asthma, n = 41; chronic obstructive bronchitis, n = 62; bronchogenic carcinoma, n = 93; pneumonia, n = 24; tuberculosis, n = 43; fibrosis, n = 22; healthy controls, n = 49). Considering all patients, AAT was found to be significantly elevated (p less than 0.01-0.001) in all methods (RID: 3.3 +/- 1.0 g/l; TIC: 2.7 +/- 0.4 g/l; NIA: 2.1 +/- 0.8 g/l) compared to healthy controls (RID: 2.1 +/- 0.3 g/l; TIC: 2.1 +/- 0.4 g/l; NIA: 1.2 +/- 0.3 g/l). The lowest mean values were found by means of the NIA method. The best correlation coefficient (R) was evaluated between the TIC and the NIA method (R = 0.96) in healthy controls, but the best correlated methods were the RID and the NIA (R = 0.93) in patients with pulmonary disease.

Adult↗
PubMed1989

[Aneurysm of the vein of Galen as a possible cause of congestive heart failure: a report of 5 new cases].

We report on five newborns with an arterio-venous malformation of the vein of Galen. All newborns were cyanotic and in congestive heart failure without any evidence of congenital heart disease. Congestive heart failure in these cases was mainly due to an almost two-fold increase in cardiac output of approximately 8 l/min/m2 (normal: 4.5 l/min/m2). According to previous reports, mortality is very high in patients with this malformation when becoming symptomatic during infancy, and therapy by surgery or embolization is only successful in 10-30%. While three of our patients died shortly after diagnosis because of untreatable heart failure, the other two were operated on either by subtotal ligation of the draining vein or by ligation of 4 arterial feeders. In the first case secondary thrombosis of the aneurysm occurred and cardiac failure subsided. In the second case a large shunt remained and a balloon-embolization was performed successfully. However, in both patients severe neurologic defects occurred, the severity of which remains to be assessed later since the post-operative observation period is only 2 and 5 months, respectively.

Cerebral Angiography↗
PubMed1988

High-performance liquid chromatographic measurement of selected blood citric acid cycle intermediates.

We describe a high-performance liquid chromatographic (HPLC) method for analysis of the intermediates of the citric acid cycle. Using two Aminex HPX-87H columns in series at 36 degrees C, the early eluting compounds cis-aconitate, oxaloacetate, alpha-ketoglutarate and citrate-isocitrate can be resolved. Acetonitrile is used for extraction of citric acid cycle intermediates from blood as interfering ultraviolet absorbing peaks are present with perchloric acid or trichloroacetic acid extraction. Acetonitrile extraction is compared with perchloric acid extraction of citric acid cycle intermediates from plasma. Low recovery of some organic acids from blood seems not to be due to enzymatic degradation. Storage of acetonitrile extracts in liquid nitrogen led to a small but significant decrease in pyruvate levels in human blood. However, significant changes in other organic acids were not seen. HPLC methodology allows study of the citric acid cycle in tissue samples as well as blood and promises to facilitate the investigation of human disorders of energy metabolism.

Acetonitriles↗
PubMed1988

3-Hydroxy-3-methylglutaryl-coenzyme A lyase deficiency: review of 18 reported patients.

3-Hydroxy-3-methylglutaryl-coenzyme A lyase deficiency (HMG-CoA lyase) is an inborn error of leucine catabolism which often leads to life-threatening illness in the neonatal period. The cardinal clinical features include severe infantile hypoglycemia, metabolic acidosis, hepatomegaly, lethargy or coma and apnea. Hyperammonemia is variable. There is a characteristic absence of ketosis. Considerable heterogeneity has been observed in clinical and biochemical presentation. Acute episodes of illness have been mistaken for Reye syndrome. The pattern of organic acids in the urine includes large amounts of 3-hydroxy-3-methylglutaric, 3-methyl-glutaconic, 3-methylglutaric and 3-hydroxyisovaleric acids. Smaller, but appreciable levels of glutaric, adipic and other dicarboxylic acids may also be excreted in the urine. Lactic acid may be present in sizable amounts at times of acute illness. The primary defect is a deficiency of 3-hydroxy-3-methylglutaryl-coenzyme A lyase, a key enzyme in the cycle of ketogenesis.

Amino Acid Metabolism, Inborn Errors↗
PubMed1988

Transcutaneous oxygen pressure measurements in type I diabetic patients for early detection of functional diabetic microangiopathy.

Seventy-six type I diabetic patients free of peripheral artery disease and 82 age-matched healthy volunteers were studied by means of transcutaneous oxygen pressure measurements. Two transcutaneous probes were attached to the skin at the subclavian region and at the supramalleolar region. Basal transcutaneous oxygen pressure values and values during breathing of 5 and 10 1 O2 min-1, the rate of rise of oxygen pressure and the time required from the beginning of the oxygen pressure increase to the achievement of its maximum were recorded, and a regional perfusion index was calculated. Nearly all the measured transcutaneous oxygen parameters showed significant differences between diabetic and control subjects. The differences were most pronounced with the transcutaneous oxygen pressure values during oxygen breathing. Even patients with a diabetes duration of less than 1 year and free of any detectable microangiopathic complication, differed significantly from control subjects. These findings may indicate a microcirculatory disturbance in diabetic patients, which might be considered as the manifestation of a functional diabetic microangiopathy preceding any morphological alterations of the vasculature in diabetes mellitus.

Adult↗
PubMed1988

Are Alzheimer patients healthier?

At an active outpatient geriatric program the gerontological team observed that Alzheimer patients appear to have fewer physical ailments than other elderly patients. To test this hypothesis, we reviewed a sample of 348 clinic patients. One hundred forty-three had a normal mental status; 75 had Alzheimer's disease as defined by DSM-III criteria; 139 had an abnormal mental status attributed to other etiologies. The number of diagnoses was compiled in each of the three groups. The average number of diagnoses in the nondemented group was 5.0 in males, 5.4 in females. In the non-Alzheimer abnormal mental status group, the average number was 5.5 in males, 4.6 in females. In contrast, the number of diagnoses in the Alzheimer group was 2.9 in males and 2.8 in females (P less than 0.0001). Cardiovascular diseases, hypertension, and cerebrovascular accidents were less frequent in the Alzheimer population. This study suggests that Alzheimer patients are physically healthier than non-Alzheimer elderly patients.

Aged↗
PubMed1987

Four outbreaks of nosocomial systemic candidiasis.

Candida albicans has recently been described as a cause of nosocomial infection. This paper reports four further outbreaks occurring over a 12-month period in England. There were 13 systemic cases and 6 deaths. The outbreaks were defined by morphotyping and the new technique of immunoblot fingerprinting. Control of the outbreaks was produced by the implementation of strict cross-infection control policies without recourse to systemic chemoprophylaxis.

Adolescent↗
PubMed1987

The effects of zero magnesium dialysate and magnesium supplements on ionised calcium concentration in patients on regular dialysis treatment.

The effect of oral magnesium carbonate or aluminium hydroxide on serum ionised calcium, total calcium, aluminium and magnesium, was assessed in 31 patients with chronic renal failure, during and after one haemodialysis. The behaviour of ionised calcium and total calcium was the same in both groups. Each showed a slight fall during dialysis, which was not significant. Serum total calcium was 0.2-0.3 mmol/l (0.8-1.2 mg/dl) greater throughout the period of dialysis in the group taking aluminium hydroxide. Serum magnesium and aluminium were both lower in the group treated with magnesium carbonate. In the group taking magnesium carbonate, serum magnesium concentrations fell markedly during dialysis, but otherwise were maintained within the reference range by the use of a magnesium-free dialysate. These results show the effectiveness of magnesium carbonate oral phosphate-binding agents and zero magnesium dialysate in reducing serum aluminium without affecting the behaviour of serum calcium fractions during dialysis.

Administration, Oral↗