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Biomedical subjects

E Schmidt

Publications and source records attributed to E Schmidt.

At least 181 records · Page 10Linked to original sources
PubMed1990

Preliminary neuropsychological test results.

A series of information processing tasks was administered to 22 PKU children aged 8.5 years who had been under dietary treatment since birth as well as to 20 controls of the same age. This contribution presents the results of two tasks from this series: a continuous performance task and a calculation task. The continuous performance task revealed a sustained attention deficit in the PKU group. In the calculation task the PKU children were slower than the controls and this difference increased with task difficulty. When the PKU sample was divided in two groups (above and below the median value of the concurrent plasma Phe level), the high Phe level group performed much worse in comparison to the low Phe level group. The latter group actually matched performance level of the controls. This could be observed for both tasks. The serum Phe level, assessed since birth over 6 month periods, correlated highly with task performance. As regards sustained attention, the Phe level measured during the 2 years preceeding test administration appeared to be an even better predictor for task performance than the concurrent Phe level, a finding which seems to underline the chronic effect of Phe on basic attention mechanisms. The results so far seem to stress the value of well-controlled dietary restrictions.

Child↗
PubMed1990

Progress in the enzyme diagnosis of liver disease: reality or illusion?

This paper discusses the progress of enzyme diagnosis by different examples. These include: the requirement for improved enzymological screening, despite the introduction of a test for hepatitis C; the imbalance between the popularity of "unexplained chronic aminotransferase elevations" and efforts to solve the inherent problems; the inadequate attempts to use the metabolic changes in the hepatocytes to improve diagnosis, prognosis, and pathophysiological understanding of viral liver diseases; the remarkable investigations into the 2'-5'-oligoadenylate synthetase for better control of interferon therapy in chronic viral hepatitis; the use of enzymes as markers of etiology, particularly for the detection of alcohol induced liver diseases; the continuing preference for the aminotransferases in this scenario although the ratios of aspartate aminotransferase over alanine aminotransferase, or of mitochondrial aspartate aminotransferase over total aspartate aminotransferase activity, largely depend on the severity and intralobular localization of damage and the stage of the liver disease.

Clinical Enzyme Tests↗
PubMed1990

Advances in the enzyme diagnosis of pancreatic diseases.

This paper reviews recent developments of analytical methods for the determination of alpha-amylase, of its isoenzymes, and of lipase. The evaluation of severity and etiology of acute pancreatitis by enzyme assays, e.g., pancreatic elastase 1, phospholipase A2, and routine enzymes are discussed. The limited significance of enzyme determinations as compared to imaging and endoscopic procedures for the diagnosis of chronic pancreatitis is demonstrated. Indirect "tubeless" tests for the evaluation of pancreatic exocrine insufficiency with respect to the secretion of chymotrypsin (chymotrypsin in stool and NBT-PABA test) and cholesterol esterase (pancreolauryl test) are reviewed. Finally, the superiority of morphologic investigations over biochemical tests for the timely detection of pancreatic carcinoma is shown.

Clinical Enzyme Tests↗
PubMed1990

Comparing cause-specific infant mortality in a West German state and the United States of America.

The infant mortality rate in North Rhine Westphalia (NRW), the most populous West German state, has continuously been around 10% higher than the German national average in the post-war period. Using white singleton data from the US 1980 National Infant Mortality Surveillance project (NIMS) and similar 1980/1981 data from NRW we compared infant mortality by birthweight and cause to describe the distribution of excess mortality in NRW. The US infant mortality rate was 8.7 deaths per 1,000 live births, compared with 13.1/1,000 for NRW (rate difference: 4.3/1,000). Of the 4.3/1,000 overall rate difference, 1.9/1,000 was attributable to neonatal deaths, 2.4/1,000 to postneonatal deaths. A major proportion, 2.0/1,000, of the overall rate difference of 4.3/1,000 was attributable to normal birthweight deaths postneonatally. 0.85/1,000 of this 2.0/1,000 rate difference was attributable to SIDS, 0.44/1,000 to external causes and 0.42/1,000 to infections.

Birth Weight↗
PubMed1990

Different types of dienelactone hydrolase in 4-fluorobenzoate-utilizing bacteria.

Of various benzoate-utilizing bacteria tested, Alcaligenes eutrophus 335, A. eutrophus H16, A. eutrophus JMP222, A. eutrophus JMP134, Alcaligenes strain A7, and Pseudomonas cepacia were able to grow with 4-fluorobenzoate as the sole source of carbon and energy. P. cepacia also utilizes 3-fluorobenzoate. Except for A. eutrophus JMP134, which is known to grow with 2,4-dichlorophenoxyacetate and 3-chlorobenzoate (R. H. Don and J. M. Pemberton, J. Bacteriol. 145:681-686, 1981), the strains were unable to grow at the expense of these compounds or 4-chlorobenzoate. Assays of cell extracts revealed that all strains express dienelactone hydrolase and maleylacetate reductase activities in addition to enzymes of the catechol branch of the 3-oxoadipate pathway when growing with 4-fluorobenzoate. Induction of dienelactone hydrolase and maleylacetate reductase apparently is not necessarily connected to synthesis of catechol 1,2-dioxygenase type II and chloromuconate cycloisomerase activities, which are indispensable for the degradation of chlorocatechols. Substrate specificities of the dienelactone hydrolases provisionally differentiate among three types of this activity. (i) Extracts of A. eutrophus 335, A. eutrophus H16, A. eutrophus JMP222, and Alcaligenes strain A7 convert trans-4-carboxymethylenebut-2-en-4-olide (trans-dienelactone) much faster than the cis-isomer (type I). (ii) The enzyme present in P. cepacia shows the opposite preference for the isomeric substrates (type II). (iii) Cell extracts of A. eutrophus JMP134, as well as purified dienelactone hydrolase from Pseudomonas strain B13 (E. Schmidt and H.-J. Knackmuss, Biochem. J. 192:339-347, 1980), hydrolyze both dienelactones at rates that are of the same order of magnitude (type III). This classification implies that A. eutrophus JMP134 possesses at least two different dienelactone hydrolases, one of type III encoded by the plasmid pJP4 and one of type I, which is also present in the cured strain JMP222.

Alcaligenes↗
PubMed1990

Enzymatic formation, stability, and spontaneous reactions of 4-fluoromuconolactone, a metabolite of the bacterial degradation of 4-fluorobenzoate.

Enzymatic conversion of 4-fluorocatechol in the simultaneous presence of partially purified preparations of catechol 1,2-dioxygenase from Pseudomonas cepacia and muconate cycloisomerase from Alcaligenes eutrophus 335 yielded a product that was unambiguously identified as (+)-4-fluoromuconolactone [(+)-4-carboxymethyl-4-fluoro-but-2-en-4-olide]. This compound was shown to be the only major product formed from 3-fluoro-cis,cis-muconate by the action of muconate cycloisomerases from A. eutrophus 335, A. eutrophus JMP134, and P. cepacia as well as by the action of dichloromuconate cycloisomerase from A. eutrophus JMP134. This finding implies that dichloromuconate cycloisomerase, like the muconate cycloisomerases, catalyzes primarily a cycloisomerization reaction, which only in the case of chloro- and bromo-substituted substrates is connected to a dehalogenation. 4-Fluoromuconolactone at pH 7 decomposes by spontaneous reactions mainly to maleylacetate, which then decarboxylates to give cis-acetylacrylate. Although significant amounts of an unidentified compound are also formed from the fluorolactone, HF elimination to the two isomeric dienelactones (4-carboxymethylenebut-2-en-4-olides) is negligible. However, all spontaneous reactions proceed so slowly that an enzymatic conversion of 4-fluoromuconolactone must be assumed. Participation of dienelactone hydrolases in this reaction is indicated by their induction during growth of various strains with 4-fluorobenzoate. However, experiments with cell extracts of P. putida A3.12 suggest that at least one other hydrolytic enzyme is able to contribute to 4-fluoromuconolactone conversion. In light of these observations, earlier proposals for a 4-fluorobenzoate degradative pathway are discussed.

Adipates↗
PubMed1990

Effect of nicotine, silver acetate, and ordinary chewing gum in combination with group counselling on smoking cessation.

Four hundred and ninety six smokers participated in a randomised comparison of the effect of silver acetate, nicotine, and ordinary chewing gum on smoking cessation. All were motivated to stop smoking abruptly and all had smoked at least 10 cigarettes a day for at least five years. Side effects and taste acceptability were related to outcome after six months. The participants attended nine meetings over a year, at which lectures, support, and advice about stopping smoking were given. Tobacco abstinence was confirmed by measurement of carbon monoxide in expired air. The chewing gums were used for 12 weeks. After 12 weeks there was a trend towards more abstainers in the nicotine group (59%) than in the silver acetate (50%) and ordinary (45%) chewing gum groups that was not quite significant (p = 0.07). At 26 and 52 weeks the number of cigarette abstainers was similar in the three treatment groups. Subjects in the nicotine chewing gum group had a longer mean time before relapse than those in the silver acetate and ordinary chewing gum groups. Mean success rates for all subjects combined at 12, 26, and 52 weeks were 52.8%, 39.7%, and 23.3%. The side effects of nicotine and silver acetate chewing gum were generally mild and transient, and unimportant except for mouth irritation from silver acetate, which had a negative effect on outcome, and the low taste acceptability of nicotine, which had a strong negative influence on the success rate. The results suggest a short term effect on nicotine chewing gum on smoking cessation, but the abstinence rates after one year were generally disappointing.

Acetates↗
PubMed1990

Sodium homeostasis in conscious dogs after chronic cardiac denervation.

The ability to regulate renal sodium excretion after an acute reduction of total body sodium by peritoneal dialysis (PD) and subsequent dietary sodium repletion was investigated in 12 [6 intact, 6 chronically cardiac denervated (CD)] conscious, chronically instrumented dogs. For 10 days, balance experiments were performed with daily measurements of mean arterial blood pressure (MABP), right atrial pressure (RAP), and heart rate (HR). The prepared diet contained 0.5 (days 1-3 after PD) or 2.5 mmol Na.kg body wt-1.day-1 (control day and days 4-9 after PD). Control values were all similar in both groups except higher fasting plasma renin activities (PRA) were observed in the CD dogs [2.6 +/- 0.4 vs. 1.0 +/- 0.2 ng angiotensin I (ANG I).ml-1.h-1; P less than 0.05]. Days 1-4 after PD, RAP fell in both groups by 2-3 cmH2O, and renal sodium excretion decreased abruptly. PRA increased to 22.8 +/- 4.1 (intact) and 29.9 +/- 4.9 ng ANG I.ml-1.h-1 (CD dogs) (day 3 after PD). Both groups continued to retain sodium, and when it was available again, PRA decreased. After the amount of sodium lost by PD was regained, the intact dogs remained in a balanced equilibrium. In the CD dogs, PRA was still above control, and they retained sodium in excess (+ 1.9 +/- 0.1 mmol/kg body wt). We conclude that the cardiac nerves are not essential for stimulating PRA and sodium retention after an acute sodium deficit. However, the inhibition of PRA and the rapid adjustment of sodium balance during sodium repletion is impaired after cardiac denervation.

Angiotensin II↗
PubMed1990

Enzyme activities and protein concentrations in serum of patients with hepatosplenic schistosomiasis.

The hepatosplenic form of Schistosoma mansoni infection contributes considerably to morbidity and mortality in endemic areas. The present study investigated serum protein concentrations and serum enzyme activities of 58 Sudanese patients with hepatosplenic schistosomiasis. All of them had a history of infection with S. mansoni and one or several episodes of oesophageal bleeding due to portal hypertension. Diagnosis was based on clinical (n = 24), ultrasonographical (n = 18) and histological (n = 16) grounds. The control group consisted of 40 Sudanese healthy blood donors. Serum albumin was found to be significantly lower in patients with hepatosplenic schistosomiasis (median = 37 g/l) than in controls (median = 47 g/l). Serum enzyme analysis revealed only minimal alterations of cellular enzyme activities, but a marked decrease of cholinesterase activity. Serum albumin concentration correlated significantly with cholinesterase activity. We conclude that liver function in patients with schistosomiasis and portal hypertension is partially disturbed. Low serum albumin and low cholinesterase activity reflected an impaired protein synthesis of the liver. Destruction of parenchymal liver cells was mild or absent.

Adolescent↗
PubMed1990

[Effect of verapamil on rate of restenosis following transluminal angioplasty of renal artery stenoses].

This prospective double-blind randomized study examined the effect of verapamil on restenosis after angioplasty of renal artery stenoses. 31 patients received placebo or 120 mg verapamil two or three times daily until the appointed day of the control angiography after 3 months. All patients received 1.5 g aspirin per day. In the control group (13 stenoses, 12 patients) the degree of stenoses increased from 35 +/- 15% immediately after PTA to 41 +/- 21% at repeat angiography 3 months after PTA, in the verapamil group (20 stenoses, 14 patients) from 35 +/- 16% to 43 +/- 22% (ns). Stenoses recurred in 23% of the stenoses in the placebo group and in 20% of the stenoses in the verapamil group (ns). 5 patients, who interrupted the therapy, were excluded from the evaluation. In the conclusion, verapamil does not decrease the incidence of restenosis after PTA of renal artery stenoses during concurrent therapy with aspirin.

Adult↗
PubMed1989

Diagnostic application of mitochondrial enzymes and isoenzymes.

Evolutionary, topological and metabolic aspects of mitochondrial enzymes and isoenzymes are reviewed, and the structural and functional heterogeneity of mitochondria is demonstrated. Primary deficiencies of mitochondrial enzymes are described and the need for their proper recognition is illustrated. Species differences of secondary dysfunction of mitochondrial enzymes are shown. The release of mitochondrial enzymes is compared to that of cytosolic enzymes from liver and heart muscle cells and the diagnostic significance of assays of mitochondrial enzymes in serum is evidenced. Possible mechanisms of mitochondrial enzyme release from cells and unresolved questions pertaining to this process are discussed in light of potential diagnostic utility of mitochondrial enzymes in serum.

Diagnosis, Differential↗
PubMed1989

Synthesis and properties of new luminescent acridinium-9-carboxylic acid derivatives and their application in luminescence immunoassays (LIA).

Two new groups of chemiluminescent acridinium labels have been presented: (a) acridinium-9-thiocarboxylates, (b) acridinium-9-(N-sulphonyl)carboxamides. Both groups show higher light yields and faster emission kinetics compared with the known acridinium carboxylate. Owing to the poor storage stability of the thiocarboxylate tracers they are not suitable for commercial use. Acridinium-9-(N-sulphonyl)carboxamides allow a variation of the structure, their stability after conjugation to antibodies is in most cases clearly better than the stability of thiocarboxylate and carboxylate tracers. Light yields and emission kinetics are also superior and good immunoassays have been developed. Therefore, this new class of chemiluminescent labels seems to be suitable for use in commercial assays.

Acridines↗
PubMed1989

Estimation of the fractional catabolic rate constants for the elimination of cytosolic liver enzymes from plasma.

Pathological elevations of the plasma activities of liver enzymes are not simply related to the quantitative release of such enzymes from the liver. Several enzymatic indices, such as the well-known de Ritis quotient, may be determined by differences in the time course of hepatic enzyme release, rather than reflecting true differences in the released quantities of various enzymes. A more quantitative use of enzymatic data is hampered by the fact that the fractional catabolic rate constants for the elimination of enzyme activities from plasma are unknown. In the present study, three of these constants are estimated by comparison of the time-activity curves in plasma with the corresponding curve of a simultaneously released, more slowly eliminated reference enzyme. This method can be applied in patients with an acute short period of hepatic enzyme release. Values obtained for the cytosolic isoforms of lactate dehydrogenase, AST and ALT are: fractional catabolic rate constant (lactate dehydrogenase isoenzyme 5) = 0.13 +/- 0.01 hr-1, fractional catabolic rate constant (cytosolic AST) = 0.088 +/- 0.016 hr-1 and fractional catabolic rate constant (cytosolic ALT) = 0.034 +/- 0.004 hr-1 (mean +/- S.E., n = 10). These values are much higher than the apparent disappearance rate constants, because of extravascular return of activity and tailing release of enzymes during the major part of the elimination phase. It is shown that these results are consistent with earlier published data on the disappearance rates from plasma of lactate dehydrogenase, AST and ALT after acute liver injury. Cumulative release of various cytosolic enzymes occurred in proportion to the corresponding activities in human control livers.

Adult↗
PubMed1989

Effects of dietary long-chain polyunsaturated fatty acids on the essential fatty acid status of premature infants.

The effect of different diets on the percentage content of long-chain polyunsaturated fatty acids (LCP; metabolites of linoleic and alpha-linolenic acids) in plasma lipids was studied in 29 premature infants on days 4 and 21 of life. Eleven infants were fed human milk which supplies LCP (1.7% of the fatty acids), 10 a commercially available milk formula without LCP, and 8 a new formula enriched with LCP of the omega-6 and the omega-3 series (0.5% LCP). LCP values in plasma lipids remained stable during the observation period in infants fed human milk. In contrast, LCP decreased markedly in plasma lipids of infants fed the conventional formula. Since the precursor fatty acids linoleic and alpha-linolenic acids were high in their diet and plasma, this finding indicates that premature infants have a limited capacity for LCP biosynthesis and may require their dietary supplementation. Infants fed the LCP enriched formula had significantly higher LCP proportions in plasma lipids than infants given the conventional formula, but less than infants fed human milk. Our results demonstrate that small concentrations of dietary LCP have marked effects on plasma lipid composition, particularly on phospholipids, suggesting that dietary LCP are preferentially channelled into structural lipids. We conclude that the essential fatty acid status of formula-fed premature infants can be improved by a supplementation of omega-6- and omega-3-LCP.

Dietary Fats, Unsaturated↗