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Biomedical subjects

C Bachmann

Publications and source records attributed to C Bachmann.

At least 163 records · Page 9Linked to original sources
PubMed1979

[Alpha-amylase determination in acute pancreatitis: selection of a reference standard].

It has been investigated which of the amylase determinations agrees most closely with the clinical diagnosis in a group of patients with acute pancreatitis and in a group with other diseases producing amylase elevation. By measuring the amylase in a urine specimen related to its creatinine concentration fewer values within the range of reference in patients with pancreatitis and also fewer falsely elevated values in the second group were observed when compared to amylase in plasma, urinary amylase activity per volume or the amylase/creatinine clearance ratio.

Acute Disease↗
PubMed1979

Short chain fatty acids in plasma and brain: quantitative determination by gas chromatography.

A reliable and practicable method for the determination of short chain fatty acids in plasma and brain tissue is presented. The sample preparation by partition chromatography on silicic acid allows subsequently a quantitation of short chain fatty acids without interference by methylmalonic acid, or other more polar compounds. With the gas-chromatographic system 2-methylbutyrate is separated from isovalerate. Reference values are given for plasma. The system is also useful in combination with mass spectrometry.

Adult↗
PubMed1979

[The effect of diuretic therapy on serum lipoproteins: an undesirable effect?].

The effect of diuretics on serum lipids and lipoproteins was evaluated in 23 patients with essential hypertension treated with chlorthalidone for six weeks. Compared to placebo conditions, diuretic therapy significantly increased serum beta (+8%, p less than 0.05) or low-density-lipoprotein (LP) cholesterol (+17%, p less than 0.025). Since alpha-LP or high-density-LP cholesterol was unchanged or tended to decrease slightly, there was also an increase in the beta/alpha-LP (+26%, p less than 0.025) or low/high-density-LP cholesterol (21%, p less than 0.025) ratio. Serum cholesterol (+4%), triglycerides (+3%), phospholipids and the Apo-LP A-I, A-II and B were not changed significantly. Blood pressure and plasma potassium were decreased (p less than 0.01), blood volume and serum insulin were not changed significantly, and serum glucose was increased mildly. Plasma renin, aldosterone and norepinephrine levels rose significantly (p less than 0.05), while circulating epinephrine was unaltered. Alterations in LP were not related to variations in blood pressure, blood volume, plasma electrolytes or serum glucose or insulin; and they did not correlate with chlorthalidone-induced increases in plasma renin, aldosterone or norepinephrine. Treatment with certain diuretics may have an adverse influence on lipoprotein metabolism.

Adolescent↗
PubMed1979

Propionyl-CoA carboxylase deficiency with overflow of metabolites of isoleucine catabolism at all levels.

An 11-year old girl with spastic paraplegia and mental retardation has suffered from attacks of metabolic acidosis since the age of 18 months. "Ketotic hyperglycinemia" was diagnosed when she was 3 years old. Reinvestigation at 9 1/2 years included a two-day load with L-isoleucine, and propionyl-CoA carboxylase assay in cultured fibroblasts. The following compounds increased following the load: 3-hydroxypropionic acid, 2-methyl-3-hydroxybutyric acid, 2-ethylhydracrylic acid, 3-hydroxy-n-valeric acid, 3-oxo-n-valeric acid, 2-methyl-3-oxobutyric acid, 2-oxo-3-methylvaleric acid, 2-methyl-3-oxovaleric acid, N-tiglylglycine, methylcitric acid and butanone. Small amounts of alloisoleucine appeared in plasma. Propionyl-CoA carboxylase deficiency was suggested by this metabolite pattern and demonstrated in cultured fibroblasts.

Acidosis↗
PubMed1979

[Determination of thyroxine in serum by a heterogeneous enzyme immunoassay: results of a joint trial].

This paper describes the evaluation of a heterologous enzyme immunoassay for the determination of total thyroxine in serum by a group of seven clinical chemical laboratories. The test follows the principles of the enzyme linked immunosorbent assay (ELISA) and uses peroxidase as a marker. The evaluation of analytical reliability yielded the following results within the analytical range from 39 unto 322 nmol/l: 1. Within-batch precision ranged from 3.1 unto 10.4% (coefficient of variation) with single analyses. 2. Between-batch precision ranged from 3.7 unto 20.4% with single analyses. 3. Between-laboratories precision ranged from 5.4 unto 6.8%. 4. Pure thyroxine, added to serum or thyroxine-free serum, gave recoveries between 93 and 120%. 5. Analysis of control sera gave results essentially comparable to the assigned values based upon radioimmunoassays. 6. Analysis of 288 clinical sera gave slightly higher results by the enzyme immunoassay than by the analogous radioimmunoassay from the same manufacturer. 7. Comparison with other methods of analysis (radioimmunoassays, competitive protein ligand assays, hormonal iodine assay) yielded partly comparable, partly higher results. 8. Comparison with the homogenous enzyme immunoassay (EMIT) led to comparable results. 9. Interference due to hyperlipemia or hemolysis was not observed. 10. There might be an interference in hyperbilirubinaemic sera, due to an as yet unknown factor. With respect to practicability the ELISA-test compares favourably with the analogous solid phase radioimmunoassay. The main differences are the absence of radioactive material and a longer shelf-live of reagents. Following the manual procedure the time taken to perform the enzyme immunoassay is slightly longer than for the analogous radioimmunoassay.

Enzyme-Linked Immunosorbent Assay↗
PubMed1979

Congenital defect in intracellular cobalamin metabolism resulting in homocystinuria and methylmalonic aciduria. II. Biochemical investigations.

Biochemical investigations are reported in an infant with methylmalonic aciduria and homocystinuria who died at 4 months of age. Postmortem analysis of liver obtained 2 weeks after the child was treated with vitamin B12 revealed deficient activity of both cobalamin dependent enzymes: N5-methyltetrahydrofolate: homocysteine methyltransferase (requiring Me-Cbl), and methylmalonyl CoA mutase (requiring Ado-Cbl). MMA-CoA mutase activity could be restored to normal in vitro by added Ado-Cbl, but MeTHF-HCy transferase activity was not significantly enhanced by addition of Me-Cbl. Though the serum total cobalamin was normal, total cobalamin in liver and kidney was abnormally low. In the kidney Me-Cbl and Ado-Cbl were disproportionally decreased whereas in the liver only Ado-Cbl was significantly reduced. This suggests that at least some of the CN-Cbl administered was converted to the coenzymes in liver which would explain the reduction of MMA- and HCy-excretion during therapy. The results show 1. that this infant suffered from a congenital defect in one of the steps of intracellular cobalamin metabolism or transport common to the synthesis of both coenzymes, 2. that life-long treatment with vitamin B12 (OH-Cbl) may be of value in similar cases, particularly if given early in the course of the disease.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1978

Purification and properties of arginase from human liver and erythrocytes.

Arginase was isolated from human liver and erythrocytes. The purification procedure used acetone precipitation, heat-treatment, (NH4)2SO4 precipitation, DEAE-cellulose chromatography and gel filtration on Sephadex G-200 in the presence of 2-mercaptoethanol. Both enzymes migrated to the anode at pH8.3 on polyacrylamide-gel electrophoresis. After incubation at pH8.0 and 37 degrees C the purified anionic liver arginase migrated to the cathode on polyacrylamide-gel electrophoresis. It is assumed that the multiple forms of the enzyme reported in the literature are partly artifacts of the purification procedure. The liver arginase showed a mol.wt. of 107000 determined by gel filtration and a sedimentation coefficient of 5.9S. Treatment of the liver enzyme with 0.25% sodium dodecyl sulphate at pH10 demonstrated an oligomeric structure of the enzyme with a mol.wt. of the subunit of 35000. The kinetic properties determined for the purified liver arginase showed an optimum pH of 9.3 and an optimal MnCl2 concentration of 2mM. The Km for L-arginine was 10.5 mM and for L-canavanine 50mM, and L-lysine exhibited a competitive type of inhibition with a Ki of 4.4mM. L-Homoarginine was not a substrate for liver arginase.

Arginase↗
PubMed1978

Increased ratio between serum beta- and alpha-lipoproteins during diuretic therapy: an adverse effect?

1. The effect of diuretic therapy on serum lipids and lipoprotein fractions was evaluated in 16 normal or labile hypertensive subjects who received in cross-over fashion chlorthalidone, frusemide or mefruside, each for 4 weeks (group A); and in 13 patients with essential hypertension treated with chlorthalidone for 6 weeks (group B). 2. All three diuretics significantly increased the ratio between serum beta- and alpha-lipoprotein fractions. This was due to an increase of the serum beta-lipoprotein fraction while the alpha-lipoprotein fraction was not changed significantly (group A) or decreased (group B). Serum cholesterol or triglycerides tended to be increased, but mean changes were often not significant. 3. The observed alterations in serum lipoproteins are consistent with the possibility of an increased risk for coronary heart disease which could offset partly the beneficial effects of a lowered blood pressure in diuretic-treated patients with hypertension.

Blood Volume↗
PubMed1977

Enzymes of ammonia detoxication after portacaval shunt in the rat. I. Carbamylphosphate synthetase and aspartate transcarbamylase.

At high systemic blood concentrations ammonia may be partially deviated into the pathway of pyrimidine synthesis, as has been observed in different genetic defects of the urea cycle. The portacaval shunt (PCS) rat presents an animal model to study ammonia detoxication without an underlying enzyme defect in the urea cycle. Since ammonia may induce a deviation into the pyrimidine pathway by influencing enzymatic reactions involved in this pathway, the activity of carbamylphosphate synthetase and aspartate transcarbamylase in liver as well as the excretion of orotic acid in the urine were measured in rats 10, 20 and 30 days after PCS. The results suggest that in this experimental model ammonia may be channeled into the pyrimidine pathway leading to a stimulation of the first enzymatic step and to an increased excretion of orotic acid.

Ammonia↗
PubMed1977

Enzymes of ammonia detoxication after portacaval shunt in the rat. II. Enzymes of glutamate metabolism.

Besides the synthesis of urea, ammonia detoxication at high concentrations can also be effected through enzyme reactions involved in glutamic acid metabolism. These mechanisms are also operative in extrahepatic tissues. Hyperammonemia is also found in the animal model of the portacaval shunt (PCS) rat. This model was chosen to study the activities of glutamate dehydrogenase, glutamine synthetase and glutaminase I in liver, brain and kidney 10, 20 and 30 days after PCS. In brain and kidney ammonia is detoxified mainly by the glutamate dehydrogenase and glutamine synthetase reactions whereas in the liver these enzyme reactions play a minor role.

Ammonia↗
PubMed1976

Congenital methylmalonic acidemia: a variant of the B12 'non-responsive' form with evidence for reduced affinity of methylmalonyl-CoA mutase for its B12-coenzyme.

Methylmalonate metabolism was investigated in fibroblasts and leukocytes of two unrelated patient with a B12-nonresponsive type of congenital methylmalonic acidemia. Intact fibroblasts from both patients showed a defective metabolism of methyl-14 c-malonate to 14CO2, whereas no such defect was found in their intact peripheral leukocytes. In disrupted fibroblasts, the conversion of methylmalonyl coenzyme A to succinyl coenzyme A was markedly reduced but was completely normalized by the addition of 5'-deoxyadenosylcobalamin (AdoCb1; 10(-5) mol/l), the specific coenzyme of methylmalonyl coenzyme A mutase. Assays with decreasing concentrations of AdoCbl (10(-5)-10(-11) mol/l) suggested a reduced affinity of the mutase apoenzyme for its coenzyme, implicating yet another variant of this heterogeneous disease.

Amino Acid Metabolism, Inborn Errors↗
PubMed1976

Gamma-glutamyltranspeptidase in the rat liver after portacaval shunt.

Gamma-Glutamyltranspeptidase (GGTP) activity was studied in livers of rats submitted to an end-to-side portacaval shunt (PCS) and in developing animals. To correlate the evolution of the enzymatic activity measured in vitro, histochemical techniques were used to localize enzyme activity in liver tissue. The GGTP activity in the adult rats was low and amounted to 2.0 +/- 0.1 mumol/min/g. During fetal development the enzyme activity rose beginning on the 15th gestational day from 630 +/- 97 to 1,058 +/- 20 on the first postnatal day. Then the values declined and reached nearly adult values from the 10th postnatal day. After PCS the GGTP activity exhibited a three- to sixfold increase (130 +/- 69 to 371 +/- 131) as compared with unoperated adult controls (53 +/- 13). the highest levels corresponded to those observed between the 3rd and 5th postnatal day in the developing rats. The histochemistry of GTTP in the fetal and newborn liver showed a regular distribution of the enzyme as a fine deposit in the hepatocytes throughout the whole tissue. Ten days after birth the activity was low, at the same level as in the adult rat. In the period after PCS hepatocytes began to show signs of enzymatic activity at the periphery of the hepatic lobules, which subsequently spread through the whole lobules. The increase of GGTP activity after PCS equaled the activity found in fetal animals. That correlated well in both groups with the reappearance of histologically demonstrable enzyme activity in hepatocytes.

Animals↗
PubMed1976

Propionic acidemia and hyperlysinemia in a case with ornithine transcarbamylase (OTC) deficiency.

A female infant with episodic hyperammonemia due to a disorder of the urea cycle and who had hyperlysinemia and an unusual elevation of short chain fatty acids, mainly propionate, is described. Both occurred apparently only during attacks of hyperammonemia. Propionic acidemia was ruled out by enzyme studies. OTC deficiency was diagnosed on the basis of: 1) decreased enzyme activity in leukocytes;2) hyperammonemia in response to protein intakes in excess of 2.0 g/kg/day; 3) orotic aciduria in the patient and her asymptomatic mother; 4) suggestive evidence of x-linked dominant inheritance; and 5) exclusion of citrullinemia, argininosuccinic aciduria, argininemia, and disorders of lysine metabolism that are associated with hyperammonemia. Homocitrullinuria, presence of epsilon-N-acetyl-l-lysine in urine, and absence of saccharopine indicate deficiency of the saccharopine pathway of lysine degradation. However, alpha-ketoglutarate reductase was normal in fibroblasts. Since these metabolites were observed only in conjunction with hyperammonemia but not after a lysine load, we suggest that there was competition between ammonia and lysine for alpha-ketoglutarate. The link between disorders of the urea cycle and short chain fatty acid metabolism remains unexplained..

Acid-Base Imbalance↗
PubMed1975

Acute neonatal nonketotic hyperglycinemia: normal propionate and methylmalonate metabolism.

Propionyl-CoA carboxylase and combined methylmalonyl-CoA (MMA-CoA) racemase and -mutase activities were studied in liver and fibroblasts of two patients with the acute neonatal form of nonketotic hyperglycemia. In all experiments, these enzyme activities studied in tissues of the patients were within the range of healthy control subjects, whereas no propionyl-CoA carboxylase activity was measurable in the fibroblasts of a patient with propionic acidemia. Subcellular fractionation of liver and fibroblasts indicated that the normal amounts of MMA-CoA found after incubation of whole tissue homogenate were formed by propionyl-CoA carboxylase, a mitochondrial enzyme, and not be acetyl-CoA carboxylase, which theoretically could also be involved in the carboxylation of propionyl-CoA. From the above data as well as from clinical and biochemical observations in three patients, it was concluded that there exists a true nonketotic hyperglycinemia which is not related etiologically to the different disorders of the ketotic hyperglycinemia syndrome. True nonketotic hyperglycinemia is not associated with ketoacidosis even after loading with propionate- and MMA precursors. It must be distinguished by exclusion from mild forms of the ketotic hyperglycinemia syndrome which may present clinically as hyperglycinemia without ketosis.

Acute Disease↗