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Biomedical subjects

J P Colombo

Publications and source records attributed to J P Colombo.

At least 19 recordsLinked 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

Plasma gamma-glutamyl transpeptidase in heroin addicts.

Plasma gamma-glutamyl transpeptidase was measured in 25 heroin addicts. The purpose was to find out if the long term administration of heroin would lead to a stimulation of GGTP due to the detoxication of this drug in the endoplasmatic reticulum of the liver. In 10 patients the elevation of GGTP could be attributed to liver damage, since other liver enzymes were also increased. 15 patients had normal GGTP activities, in 4 of them accompanied by minor elevations of single other hepatic enzymes. In 11 patients the GGTP activity as weel as that of the other enzymes was normal despite heavy chronic herioin abuse. It is therefore improbable that GGTP can be used to diagnose abuse of this drug and to evaluate the progress of drug detoxication treatments and drug abstention as has been proposed in chronic alcoholism.

Adolescent↗
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 enzyme induction on diazepam metabolism in man.

1 The elimination and metabolism of diazepam in man was investigated following the induction of the liver microsomal enzyme system by antipyrine. 2 Seven healthy volunteers were given 1200 mg antipyrine as an inducing agent for a period of 14 days. Before and after the induction period the elimination of diazepam and desmethyldiazepam was measured in the plasma by gaschromatography. As parameters of liver microsomal enzyme activity, antipyrine elimination and gamma-glutamyl-transpeptidase in the plasma, D-glucaric acid and 6-beta-hydroxycortisol urinary excretion were measured on both occasions. 3 Following the induction period most parameters of microsomal enzyme activity measured were significantly changed indicating an increase of the microsomal enzyme system. The elimination of diazepam was significantly altered having a half-life of 37 h before and 18 h afterwards combined with a significant increase in total body clearance after the induction period, although the volume of distribution remained unaltered. The formation of the main metabolite N-desmethyldiazepam was not changed, but its elimination was increased having a half-life of 139 or 58 h respectively. 4 The elimination of unchanged diazepam and desmethyldiazepam is significantly increased by the induction of the liver microsomal enzyme system using antipyrine as an inducing agent in healthy volunteers, which might be important under certain clinical conditions.

17-Hydroxycorticosteroids↗
PubMed1979

Influence of indicating enzyme reaction on apparent creatine kinase activity creatine kinase in serum, VII.

Comparison of the indicative systems yeast glucose-6-phosphate dehydrogenase/NADP+, leuconostoc glucose-6-phosphate dehydrogenase/NADP+ and leuconostoc glucose-6-phosphate dehydrogenase/NAD+ showed excellent correlation and no differences in apparent creatine kinase activity with the two methods using NADP+. By using NAD+ with the leuconostoc enzyme enzyme relative recovery of apparent creatine kinase activity is lower due to interference of other serum constituents. The mean value of the relative differences versus methods using NADP+ was 5.8% in our experiments.

Creatine Kinase↗
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

[Morphological liver changes after portacaval and splenocaval anastomosis in rats].

Body weight, liver weight and liver histology in rats 3 weeks after portacaval and distal splenocaval anastomosis were analyzed. Rats with portacaval shunt showed a reduction of body and liver weight and histological signs of liver atrophy. There was no difference between the results in rats with splenocaval shunt and controls.

Animals↗
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↗
PubMed1977

The influence of prednisolone on hepatic function in normal subjects. Effects on galactose elimination capacity, sulfobromophthalein transport maximum and storage capacity, and D-glucaric acid output.

In view of the importance of liver tests in the follow-up of patients under treatment with corticosteroid hormones, 20 mg of prednisolone were given by mouth to normal volunteers for 4 days and hepatic function was assessed before and during treatment. Despite significant falls in plasma cortisol and serum bilirubin concentrations, the galactose elimination capacity, the BSP tests, and the urinary D-glucaric acid output remained essentially unchanged. Consequently no pharmacological effect of this corticosteroid hormone on the examined tests could be detected.

Administration, Oral↗