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Biomedical subjects

J H Stromme

Publications and source records attributed to J H Stromme.

At least 19 recordsLinked to original sources
PubMed1998

Severe organophosphate (demeton-S-methyl) poisoning in a two-year-old child.

A previously healthy 2-y-old boy was admitted to the hospital 30 min after the ingestion of 10 ml of demeton-S-methyl (META-SYSTOX). Treatment consisted of gastric decontamination, atropine, reactivator (obidoxime) and supportive therapy. Atropine was given to control the muscarinic features. Assisted ventilation was required for 6 h; however, this treatment was able to be discontinued following the second injection of obidoxime 11.5 h after the ingestion. Excess salivation and slight bradycardia were easily controlled with small doses of atropine for 5 d following admission to Ullevaal Hospital. Further course was uneventful, and the patient was discharged on the 8th d without any sequelae. Plasma cholinesterase levels were initially low (<400 U/l), but returned to reference values upon discharge. In this case, adequate supportive therapy and the rapid administration of both atropine and obidoxime were clearly associated with a favorable outcomes

Antidotes↗
PubMed1997

Effects of clodronate on cortical and trabecular bone in ovariectomized rats on a low calcium diet.

The aim of this study was to evaluate the contribution of a low calcium diet to the cortical and trabecular osteoporosis seen in ovariectomized rats after 7 weeks on a low calcium diet and to investigate the effects of the bisphosphonate clodronate on this development of osteoporosis. Thirty-six mature, female Wistar rats were randomized into four groups: Ovx-B (bisphosphonate) and Ovx-C (control) were ovariectomized, and Sham-Ca (low calcium) and Sham+Ca (normal calcium) were sham operated. The first three groups were fed a low calcium diet (0.01%) and Sham+Ca normal rat chow (Ca 1.1%). The Ovx-B received 10 mg/kg s.c. clodronate daily for nine weeks, and Ovx-C, Sham-Ca, and Sham+Ca received the same volumes of saline. Bone mineral turnover measured as 85Sr-uptake was increased in all low calcium groups compared to Sham+Ca. The Sham+Ca femora had higher dry weight and ash weight than the other groups, and Ovx-C had higher dry weight compared with Ovx-B and Sham-Ca. Calcium content was lower in both Ovx groups compared to both Sham groups. Magnesium was lower in all groups compared to Sham+Ca and higher in Ovx-B compared with Ovx-C. In the femoral shaft, Sham+Ca had significantly higher ultimate bending moment, energy absorption, and deflection compared to the other three groups. Ultimate bending moment was higher in Sham-Ca than in Ovx-C. Stiffness was increased in both Sham+Ca and Ovx-B compared to Ovx-C. The maximum stress in the femoral midshaft was higher in Sham+Ca than in the other groups, and higher in Ovx-B than in Ovx-C. Histomorphometry showed increased medullary area in all low calcium groups compared to Sham+Ca and larger cortical area in Sham+Ca and Ovx-B compared to Ovx-C. Compared to Sham+Ca the trabecular bone volume was decreased to 30% in Sham-Ca and to 9% in Ovx-C, but was unchanged in Ovx-B. The low calcium diet generally increased bone mineral turnover and reduced the tibial bone volume. Femoral changes led to a reduction of cortical fracture strength and maximal stress. Ovariectomy in addition to a low calcium diet reduced femoral strength even more. Daily injections of clodronate to ovariectomized rats on a low calcium diet increased femoral shaft stiffness and maximum stress, and clodronate preserved both trabecular and cortical tibial bone volume completely.

Animals↗
PubMed1982

Enzymatic characteristics of tubular adenomas and carcinomas of the large intestine.

Enzymes activities in homogenates of the large intestine were measured in biopsies from 11 tubular adenomas and six carcinomas and from the corresponding normal mucosa of each individual. A similar and significant increase was found in the total activities of glucose-6-phosphate dehydrogenase (G 6 PD), pyruvate kinase, and lactate dehydrogenase in adenomas and carcinomas as compared with the levels of normal mucosa. The lactate dehydrogenase isoenzyme patterns showed also a marked and similar change in the adenomas and carcinomas with a significant increase of lactate dehydrogenase M-monomers. Most of the adenomas showed slight to moderate dysplasia. The results indicate that the measurement of total G 6 PD, pyruvate kinase and lactate dehydrogenase activities for screening purposes has no predictive value in separating non-premalignant from premalignant adenomas. Moreover, it seems that the enzymatic characteristics of malignancy are present even in tubular adenomas. This is in agreement with the theory of a polyp-cancer sequence.

Adenoma↗
PubMed1982

Application of response surface methodology to the assay of gamma-glutamyltransferase.

Response surface methodology (RSM) offers an empirical approach to the study of clinical enzyme assays. Variables such as pH, which are difficult to characterize by using theoretical enzyme kinetics, are easily included in RSM formulations. In this investigation, we studied with RSM the change in the measured activity of gamma-glutamy-transferase (EC 2.3.2.2) as a function of changes in concentrations of donor (gamma-glutamyl-3-carboxy-4-nitroanilide) acceptor (glycylglycine), and pH. The study defined large ranges for these variables over which maximum enzyme activity is obtained: donor 6.6 to 10.2 mmol/L, acceptor 129 to 250 mmol/L, and pH 7.8 to 8.5. The RSM regression polynomial was as accurate as a previously determined enzyme kinetic equation for predicting the transferase activity from given reagent substrate concentrations. Although not yielding a mechanistic understanding of an enzyme assay, RSM studies do produce an operational understanding of how an assay functions.

Clinical Enzyme Tests↗
PubMed1977

The influence of changes in the phospholipid pattern of intact fibroblasts on the activities of four membrane-bound enzymes.

Human skin fibroblasts, grown to confluency in the presence of 32P for random labelling of the phospholipids, showed upon 24 h incubation in the presence of either 8 mM L-serine or 4 mM ethanolamine an increased content of phosphatidylserine (150% of control cells) or phosphatidylethanolamine (116% of control cells), respectively. Concomitantly the phosphatidylcholine correspondingly decreased. Upon cell harvesting and gentle enzyme preparation the base-treated cells demonstrated a significantly higher unstimulated, fluoride- and thyrotropin-stimulated activity of adenylate cyclase. The activities of total ATPase, ouabain-sensitive ATPase, 5'-nucleotidase and gamma-glutamyltransferase remained unaltered. When subjecting enzyme preparations from fibroblasts to ultrasonication the activity of adenylate cyclase decreased progressively with energy applied, whereas the activities of the other enzymes were unaltered ((K+ + Na+)-ATPase, 5'-nucleotidase) or even increased (Mg2+-ATPase, gamma-glutamyltransferase). The results have a bearing upon the regulatory function of the phospholipid microenvironment of membrane-bound enzymes.

Adenosine Triphosphatases↗
PubMed1976

Gamma-Glutamyl-3-carboxy-14-nitroanilide: the substrate of choice for routine determinations of gamma-glutamyl-transferase activity in serum?

Gamma-Glutamyl-3-carboxy-4-nitroanilide has been tested as donor substrate in the assay of gamma-glutamyltransferase activity in serum, glycylglycine being used as acceptor substrate. This donor substrate is highly solube even in neutral solutions, in contrast to the commonly used gamma-glutamyl-4-nitroanilide. The enzyme which apparently acts accordingly to a ping-pong bi bi kinetic mechanism, shows an absolute KM value for gamma-glutamyl-3-carboxy-4-nitroanilide of about 0.64 mmol/l, and for glycylglycine of about 13.4 mmol/l. The former KM value is significantly lower than that previously found for gamma-glutamyl-4-nitroanilide. The carboxyl derivative exhibits a marked competitive inhibitory effect on the gamma-glutamyltransferase. This effect is more pronounced than that of gamma-glutamyl-4-nitroanilide. The carboxyl derivative has somewhat higher absorbance in the range of wave length (400-420 nm) used to monitor the formation of the product. It is concluded that as donor substrate in the assay of gamma-glutamyltransferase activity of serum, the new derivative is not substantially superior to the gamma-glutamyl-4-nitroanilide conventionally used.

1-Carboxyglutamic Acid↗
PubMed1976

Dopamine-beta-hydroxylase activity in serum following acute myocardial infarction: an evaluation of this parameter for routine use as an index of sympathetic activity.

Dopamine-beta-hydroxylase activity was measured in sera from 114 normal males and from 11 patients on the 1st, 2nd, 3rd, 5th and 10th day following acute myocardial infarction. A significant elevation of dopamine-beta-hydroxylase levels (P less than 0.001) was found during the first two days after infarction when compared with the 10th-day values. Only a few activities were above the reference range. Temporary elevations of glucose and glycerol levels were also found. Assay of serum dopamine-beta-hydroxylase may be a useful parameter of sympathetic activity in longitudinal studies in which each individual is used as his own reference.

Adult↗
PubMed1976

Gamma-glutamyltransferase: Substrate inhibition, kinetic mechanism, and assay conditions.

Gamma-glutamyltransferase activity in serum is shown to be competitively inhibited by the two substrates gamma-glutamyl-4-nitroanilide and glycylglycine. Awareness of this is of importance when one is choosing final reaction conditions for the assay of the enzyme. Gamma-glutamyltransferase probably acts by a "ping-pong bi-bi" kinetic mechanism, which fits with the double competitive substrate inhibition demonstrated. The product, 4-nitro-aniline, appears to be an uncompetitive dead-end inhibitor of both substrates. Various amino acids, particularly glycine and L-alanine, inhibit the enzyme. Their inhibition patterns are uncompetitive with glycylglycine and competitive with gamma-glutamyl-4-nitroanilide. On the basis of the present and other studies, the Scandinavian Society for Clinical Chemistry and Clinical Physiology is going to recommend for routine use a gamma-glutamyltransferase method in which the final concentrations of gamma-glutamyl-4-nitroanilide and glycylglycine are 4 and 75 mmol/liter, respectively.

Amino Acids↗