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Biomedical subjects

G Lindstedt

Publications and source records attributed to G Lindstedt.

At least 19 recordsLinked to original sources
PubMed1979

Effect of secretin and cholecystokinin-pancreozymin on plasma CEA concentration in patients with pancreatic carcinoma and pancreatitis.

Plasma CEA concentration before and after administration of secretin and cholecystokinin-pancreozymin has been determined in 89 patients with neoplastic or inflammatory pancreatric disease and other neoplastic and nonneoplastic disorders. The purpose of the study was to expore the specificity and sensitivity of such a provocation tests. Some rise of the plasma CEA concentration after hormonal stimulation could be observed in several patients in the various groups. However, none of the 37 patients with nonpancreatic disease who had a basal CEA concentration of 6 micrograms/l or less had a maximal CEA concentration above 13 micrograms/l after the stimulation whereas 7 out of 31 patients with pancreatic disease (3 with pancreatic carcinoma and 4 with chronic pancreatitis) showed such an elevation of plasma CEA concentration. Thus, the provocation test showed a satisfactory specificity for pancreatic disease but a low sensitivity. It is suggested that the possibility of an effect of physiologically released gastrointestinal hormones should be considered when "unexplained" high CEA values are found in plasma samples from nonfasting patients.

Animals↗
PubMed1979

Dissolution of cobalt from hard metal alloys by cutting fluids.

On grinding hard metal alloys containing cobalt, the dissolution of cobalt during 5 days was studied for nine commercial cutting fluids. After 1 day, a major part of the cobalt liberated from the material ground is found in solution. This percentage decreases when grinding is continued using the same coolant fluid. Only a small fraction of the cobalt is found in particles in the circulating fluid. The bulk must be in the sediment in the storage tank, where it does no harm to the workers' skin. The final concentration of cobalt found in some fluids may be hazardous.

Air Pollutants, Occupational↗
PubMed1979

Individual mercury exposure of chloralkali workers and its relation to blood and urinary mercury levels.

On two occasions, chloralkali workers were investigated with regard to personal air mercury exposure, blood mercury and urinary mercury. The first investigation (13 workers, 2 weeks) was made at an exposure above the threshold limit value (64 microgram/m3, range 36--112), the second (16 workers, 8 weeks) at a lower exposure (23 microgram/m3, range 15--43). At the higher level of exposure, good correlations were found between air exposure and blood or urinary mercury for the group, but not for individuals. At the lower level, the correlations were less pronounced for the group. For individuals, the best correlation was found between mean air exposure during one week and blood mercury about half a week later. Other individuals, mainly the least exposed, showed no such correlation. Corresponding correlations were not found for urinary mercury. The urinary excretion rate was determined only for the last few hours of the workday, but the results agree with earlier investigations of 24-h excretion on a group basis. The threshold limit value for mercury in air (50 microgram/m3) corresponds to 150--175 nmol Hg/1 blood (= 30--35 microgram/1) for the group, with large individual variation.

Adult↗
PubMed1978

Malabsorption of fat and vitamin B12 before and after intestinal resection for Crohn's disease.

Intestinal absorption of fat and vitamin B12 was studied prospectively in 136 patients with Crohn's disease localized to the ileum and/or the colon. Fecal fat was measured in 3-day periods on a high fat diet, and vitamin B12 absorption was assessed by the Schilling test. When related to the extent of the ileal disease there was a poor correlation to both fecal fat excretion and the result from the Schilling tests, but an exponential and highly significant correlation was found between the results of both tests and the length of the resected ileal segment. Accepting a change in either direction not exceeding 10% of the preoperative test value as unchanged, three-fifths of the patients deteriorated and one-fifth improved in fat-absorption, whereas half the patients deteriorated and one-third improved in vitamin-B12 absorption after surgery. When related to the length of the ileum resected, the test results were about the same in patients subjected to a restorative procedure sparing the major part of the colon and in ileostomy patients. Absorption of fat and vitamin B12 did not change with time elapsing from operation, indicating that there were no compensatory mechanisms as regards absorption of these substances.

Adult↗
PubMed1977

No inhibition by Li+ of thyroxine monodeiodination to 3,5,3'-triiodothyronine and 3,3',5'-triiodothyronine (reverse triiodothyronine).

The possibility that lithium affects the conversion of thyroxine to 3,5,3"-triiodothyronine and 3,3',5'-triiodothyronine (reverse triiodothyronine) was studied by measurement of the serum concentractions of these parameters in five patients during the first week of lithium therapy. In three patients there was a decrease in serum thyroxine concentration and a slightly less pronounced decrease in that of serum 3,5,3'-triiodothyronine. In two patients, who also received L-tryptophan or flupentixol, no change was noted in the concentrations of these compounds. There was no increase in serum 3,3',5'-triiodothyronine concentration in any of the patients. No systematic change was found in the serum concentrations of thyrotropin or unsaturated thyroid-hormone binding proteins. The results obtained do not support the contention that lithium should inhibit the monodeiodenation of thyroxine to its active and inactive metabolites.

Adult↗
PubMed1977

Purification and properties of gamma-butyrobetaine hydroxylase from Pseudomonas sp AK 1.

gamma-Butyrobetaine hydroxylase (4-trimethylaminobutyrate, 2-oxoglutarate:oxygen oxidoreductase (3-hydroxylating), EC 1.14.11.1) has been isolated from Pseudomonas sp AK 1 by ion-exchange, adsorption, and molecular-sieving chromatography. The preparation was homogeneous as judged from electrophoresis in agarose and polyacrylamide gels, isoelectric focusing, and equilibrium sedimentation. The molecular mass was 95 kdaltons as determined by sedimentation equilibrium centrifugation. From electrophoresis in polyacrylamide gel the molecular mass was estimated to 92 kdaltons, from gel filtration through columns of Sephadex G-200 to 86 kdaltons, and from gel filtration through thin layers of Sephadex G-150 and G-200 to 82 kdaltons. Calculation of molecular mass from Stokes radius, sedimentation coefficient, and partial specific volume gave a value of 96 kdaltons, and from the sedimentation coefficient, 93 kdaltons. Gel filtration through Sephadex G-200 in 6 M guanidinium chloride and electrophoresis in polyacrylamide gel containing 3.5 mM sodium dodecyl sulfate resulted in single bands with mobilities corresponding to molecular masses of 39 and 37 kdaltons, respectively, indicating that the enzyme is composed of two polypeptides chains with similar size. NH2-terminal amino acid sequencing in three cycles resulted in two amino acids in each cycle (Ala + Asn, Ala + Ile, Ala + Ile). The Stokes radius was 3.8 nm, corresponding to a diffusion coefficient of 5.7 X 10(-7) cm2/s. A sedimentation coefficient of 5.8 X 10(-13) s and a frictional ratio of 1.26 was found. The partial specific volume was 0.729 mL/g at 20 degrees C as calculated from amino acid analysis. The isoelectric point was 5.1, as determined by isoelectric focusing analysis. The light absorption in the ultraviolet and visible regions was that of a protein without light-absorbing prosthetic groups. The absorption coefficient at 280 nm of a 1.0% solution at pH 6.5 was 12.6. Amino acid analysis by ion-exchange chromatography showed a half-cystine content of 19 mol per 95 kg of protein (23 residues/1000). Thirteen sulfhydryl groups were found by colorimetric analysis before as well as after reduction with NaBH4, indicating absence of disulfide bonds. Less than 0.1 mol of iron was found per mol of enzyme.

Amino Acids↗
PubMed1977

Thymine 7-hydroxylase from Neurospora crassa. Substrate specificity studies.

A partially purified preparation of thymine 7-hydroxylase (thymine, 2-oxoglutarate : oxygen oxidoreductase (7-hydroxylating), EC 1.14.11.6) from Neurospora crassa was incubated with a number of pyrimidines chemically related to tyymine. 1. Pyrimidines with oxygen or sulfur substituents on atoms Nos. 2 and 4 as well as an alkyl group on atom Nos. 1 or 5 were substrates. 2. Km values were determined for 1-methyluracil, 1-ethyluracil, thymine, 6-azathymine, 1-methylthymine, 1-ethylthymine, 5-formyluracil and 5-hydroxymethyluracil. 3. Uracil was identified as one of the metabolites after incubation with 1-methyluracil. The one-carbon metabolite has not been characterized. 4. Several pyrimidines with polar groups on atoms Nos. 2 and 4 were inhibitory. 5. Addition of 1-methyluracil, 1-methylthymine, 1-ethylthymine or 5-hydroxymethyluracil to incubations with thymine and 2-oxo[1-14C1]glutarate did not result in additional formation of 14CO2, indicating that the same enzyme acts on the different compounds. It has previously been found (Bankel, L., Holme, E., Lindstedt, G. and Lindstedt, S. (1972) FEBS Lett. 21, 135-138) that a mutant strain of N. crassa which is devoid of thymine 7-hydroxylase activity also lacks ability to perform the coupled oxygenation of 2-oxoglutarate and 1-methyluracil, 5-hydroxymethyluracil and 5-formyluracil, respectively. It is concluded that one and the same oxygenase is responsible for the activities studied.

Ketoglutaric Acids↗