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Biomedical subjects

G Steen

Publications and source records attributed to G Steen.

At least 37 records · Page 2Linked to original sources
PubMed1987

Isoprenoid biosynthesis in multiple sclerosis, II. A possible role of NADPH.

Genetic predisposition in MS, influence of fat consumption on the disease, and excretion of lipid metabolites in urine led us to investigate isoprenoid metabolism in this disease. Ubiquinone concentration and biosynthesis was normal in lymphocytes. Cytochrome oxidase, which contains an isoprenoid side chain, was normal in activity. Cholesterol biosynthesis from acetate was found to be elevated in MS, and so was triglyceride biosynthesis. Increased biosynthesis may offer a very simple explanation to all the metabolites excreted (3-methylglutaconic acid, 2-hydroxy-2-methyl-3-butenoic acid and adipic acid). Increased biosynthesis may be caused by an elevated NADPH/NADP ratio, since such an elevation may also account for many other biochemical anomalies in MS. Elevated NADPH/NADP ratio may be of direct importance in the pathogenesis.

Cholesterol↗
PubMed1987

Cognitive function, cognitive style and life satisfaction in a 68-year-old male population.

A representative sample of 68-year-old men living in the city of Malmö, Sweden, was examined by means of psychological tests and questionnaires regarding cognitive capacity, cognitive style as an expression of personality, and life satisfaction. Reference values for these parameters are presented, and a continuous cohort increase of verbal ability could be identified in this age group. That the prevalence of cognitive reduction was found to be surprisingly high is tentatively interpreted as reflecting an underdiagnosis of these symptoms as concomitant to other diseases in the general population. Earlier results supporting the concept of terminal decline could not be replicated. The reason for this might be that the present population was somewhat younger than those earlier investigated. Contrary to expectation, life satisfaction did not correlate to either cognitive reduction or cognitive style. It had, however, a positive correlation to measures of fluid intelligence.

Adaptation, Psychological↗
PubMed1987

Screening of patients admitted to a geriatric hospital with supposed organic dementia.

75 patients, aged 69 to 97 (mean 84) years, admitted to a geriatric clinic with symptoms or signs of organic brain failure, were examined with a wide test battery including chemical analyses, electroencephalogram (EEG), regional cerebral blood flow (rCBF) measurement, and psychometric tests. There was a prevalence of 89% organic dementia, 3% treatable dementia, and 8% non-dementia conditions. Thus the prevalence of treatable conditions was rather low (11%). Multi-infarct dementia was more prevalent (52%) than dementia of Alzheimer type (31%). All but one of the non-dementia conditions were due to confusional reaction. In no case was depression, drug intoxication, or deafness the only cause of symptoms. After a follow-up period of 6 months, 33% of the patients had died. An autopsy was performed in 80% of these cases, and the clinical diagnosis was confirmed in all but four cases.

Aged↗
PubMed1985

Isoprenoid biosynthesis in multiple sclerosis.

Recently discovered metabolites in urine have suggested a defect of isoprenoid metabolism in multiple sclerosis. Lymphocyte HMG-CoA reductase was found unaffected however, and so was lymphocyte biosynthesis of geraniol, farnesol and squalene from mevalonolactone. The level of dolichol in white matter of an MS brain was similar to that of a control sample. Serum ubiquinone, on the other hand, was decreased in multiple sclerosis. Ubiquinone in serum was both age-dependent and related to serum cholesterol. Active as well as stable MS displayed a decreased level of serum ubiquinone, and a reduced ubiquinone-cholesterol ratio. These results are compatible with a deficient ubiquinone biosynthesis in multiple sclerosis.

Adult↗
PubMed1983

3-Methylglutaconic aciduria in two infants.

We studied two children who developed normally for the first 3-4 months of life and then displayed a failure-to-thrive syndrome, regression in psychomotor development, pronounced muscular hypotonia, and liver damage. At the age of about 1-2 years, optic atrophy and spastic parapareses were evident. One child died at the age of 2.5 years the other at an age of 4 years. Both children excreted 3-methylglutaconic acid, 0.1-0.4 mol/mol creatinine and 3-methylglutaric acid, 0.02-0.05 mol/mol creatinine. The excretion of 3-hydroxy-3-methylglutaric acid was not increased. One of the children was available for further biochemical studies. The activity of hydroxymethylglutaryl-CoA lyase (EC 4.1.3.4) was moderately reduced in leucocytes and fibroblasts. During a 21-h fast there was a normal formation of ketone bodies and we conclude that the cause of the syndrome is not a deficiency of hydroxymethylglutaryl-CoA lyase. Normal formation of 14CO2 from [1-14C]isovaleric acid and [2-14C]leucine in fibroblasts and leucocytes apparently excludes a deficiency of methylglutaconyl CoA-hydratase (EC 4.2.1.18).

Creatinine↗
PubMed1983

Organic acids or urine in multiple sclerosis.

The urinary excretion of organic acids was examined in 509 cases with multiple sclerosis and in 50 age- and sex-matched controls. The concentrations of the acids were related to creatinine. No differences were found for compounds such as glycolic acid, 2-methyl-3-hydroxybutyric acid, 2-ethylhydracrylic acid, 4-hydroxyphenylacetic acid, suberic acid and many other acids. However, the mean excretion of 2-hydroxy-2-methyl-3-butenoic acid was increased two-fold in the MS group. 2 MS cases had a very high excretion of 3-methylglutaconic acid, and another 6 cases had moderate elevations, which were fairly constant over a time period of several months. Moderate elevations were also noted in 2 healthy controls. 1 MS case had a very high excretion of 3-hydroxyisovaleric acid. 7 MS cases, and none in the control group, had elevated excretion of adipic acid. Differences were also noted for lactic acid, succinic acid, aconitic acid and 3-methyladipic acid. An oral dose of deuterium-labelled acetate was given to one of the patients with high excretion of 3-methylglutaconic acid. Deuterium was incorporated into this metabolite. 3-methylglutaconic acid, 2-hydroxy-2-methyl-3-butenoic acid, 3-hydroxy-isovaleric acid and 3-methyladipic acid are all potential isoprenoid metabolites. A possible defect in the pathway of isoprenoid biosynthesis is discussed.

Aconitic Acid↗
PubMed1983

2,6-Dimethyloctanedioic acid--a metabolite of phytanic acid in Refsum's disease.

The urine of two patients with Refsum's disease consistently contained 2,6-dimethyloctanedioic acid, a compound not normally found in human urine. In addition, their urines contained increased concentrations of 3-methylhexanedioic acid. These two compounds may be formed from phytanic acid by an initial omega-oxidation and subsequent beta-oxidations. It was calculated that this oxidation pathway may metabolize at least 30 mg of phytanic acid per day.

Acyclic Monoterpenes↗
PubMed1982

Identification of 4,6-dioxoheptanoic acid (succinylacetone), 3,5-dioxooctanedioic acid (succinylacetoacetate) and 4-Oxo-6-hydroxyheptanoic acid in the urine from patients with hereditary tyrosinemia.

In the urine from patients with hereditary tyrosinemia, three characteristic compounds have been found. They have been identified as 4,6-dioxoheptanoic acid (succinylacetone), 3,5-dioxooctanedioic acid (succinyl-acetoacetate) and 4-oxo-6-hydroxyheptanoic acid. The identities have been established by mass spectrometry of several derivatives, and by comparison with a synthetic sample of 4,6-dioxoheptanoic acid.

Acetoacetates↗
PubMed1982

A new rating scale for dementia syndromes.

A new scale, the GBS-scale, is constructed for rating dementia syndromes. The scale is divided into four subscales measuring motor, intellectual and emotional functions and different symptoms characteristic for dementia. The scale can be used by physicians, psychologists and registered nurses. The reliability of the scale is tested by rating 100 patients in somatic and psychogeriatric long-term care. The raters worked independently of each other and were recommended to confer with the staff about the status of the patient. The agreement between the raters was good. The validity of the scale was tested by comparing it with another geriatric rating scale. High correlations between the two scales were seen and indicated that the new scale measures dementia syndromes. The new scale measures degree of dementia and profiles of dementia syndromes. It is constructed in such a way that it can measure changes in dementia symptoms over a certain amount of time. Thus, it can be used in evaluating effect of treatment. It is not, however, meant to be a diagnostic scale.

Aged↗
PubMed1982

In-use tests of disinfectants.

In two different laboratories three methods were applied for in-use testing of 400 samples of disinfectants, primarily aldehyde and phenolic solutions, collected in 30 wards at 11 Danish hospitals. The results obtained with the Kelsey-Maurer test, the membrane filtration technique, and a standardized challenge test were in complete accordance, however, the challenge test revealed a few more inefficient samples, than the two other methods. For routine use at hospital laboratories the choice between the Kelsey-Maurer test or the modified Kelsey-Maurer technique using membrane filtration may be guided by the available equipment. The design and the application of a challenge test and pertinent criteria for test strains are discussed. Only about 3% of the samples failed to pass the tests, but a predominance (10%) of failures among the samples, received as number one in a series, underlines the didactic aspects of in-use testing. The study demonstrates that suitable methods exist and may be of value when introduced in the local policy of controlling disinfectants.

Bacillus↗
PubMed1981

Urinary amino acids and organic acids in the Sjögren-Larsson syndrome.

A metabolic study of urine samples obtained from 35 patients with the Sjögren-Larsson syndrome (SLS) has been performed by means of a series of chemical tests, as well as by analysis of the amino acid pattern by high-voltage paper electrophoresis. Organic acids were analysed by gas-chromatography-mass spectrometry and qualitative analyses for mono- and disaccharides were performed by thin-layer chromatography on cellulose. No error in the amino acid, organic acid or carbohydrate metabolism was found in the SLS-patients in the present study.

Adolescent↗
PubMed1981

On the renal tubular damage in hereditary tyrosinemia and on the formation of succinylacetoacetate and succinylacetone.

Phenylalanine and homogentisate increase the concentration of succinylacetoacetate and succinylacetone both in serum and urine in patients with hereditary tyrosinemia and therefore increase the excretion of 5-aminolevulinate. Both phenylalanine and homogentisate cause a tubular proteinuria which is in agreement with our hypothesis that their metabolites maleylacetoacetate and fumarylacetoacetate are the toxic compounds in hereditary tyrosinemia. The patient with the highest excretion of succinylacetoacetate and succinylacetone has the slightest tubular proteinuria whereas the one with the lowest excretion of these compounds has the more pronounced tubular proteinuria. It is suggested that this is caused by a difference in the ability to reduce the presumed toxic compounds fumarylacetoacetate and maleylacetoacetate, i.e. the precursors of succinylacetoacetate.

Acetoacetates↗
PubMed1981

Propionyl-CoA carboxylase deficiency: case report, effect of low-protein diet and identification of 3-oxo-2-methylvaleric acid 3-hydroxy-2-methylvaleric acid, and maleic acid in urine.

Vomiting, lethargy and metabolic acidosis were the main initial symptoms of metabolic disease in a 1 month old girl. Her older sister had died from a similar disease, considered to be Reye's syndrome, at an age of 15 months. The urine of the present case contained 2-methylcitric acid, 3-hydroxypropionic acid, N-propionylglycine, 2-hydroxy-3-methylbutyric acid, N-tiglylglycine, 3-hydroxyvaleric acid and glutaric acid. These metabolites are all known to be associated with propionyl-CoA accumulation. Free propionic acid was not detected in the urine. In addition, the urine contained 3-oxo-2-methylvaleric acid and 3-hydroxy-2-methylvaleric acid, probably formed by condensation of two molecules of propionyl-CoA. The identity of these metabolites was confirmed by synthesis. An elevated urinary concentration of maleic acid and fumaric acid was another constant abnormality. The activity of propionyl-CoA carboxylase in leucocytes was about 20% of the normal activity. The girl was teated with a low-protein diet since the diagnosis was made at an age of 1 month, and her psychomotor development was satisfactory at an age of 2 1/2 years. She had a few episodes of acidosis during infections.

Amino Acid Metabolism, Inborn Errors↗