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Biomedical subjects

H Thies

Publications and source records attributed to H Thies.

At least 19 recordsLinked to original sources
PubMed2001

Ion chromatographic determination of lithium at trace level concentrations. Application to a tracer experiment in a high-mountain lake.

The water residence time of a high-mountain seepage lake in the Austrian Alps was derived from the flushing rate of a tracer substance. A diluted lithium chloride solution was injected into the lake during holomictic conditions in order to favour the homogeneous distribution of the tracer. The exponential decline of the mass of lithium in the lake revealed a water residence time of 1.5 to 3 months for summer and almost no lake water exchange during winter. Lithium concentrations ranged from background values of 0.06 microg l(-1) to about 3 microg l(-1) immediately after the tracer injection. Lake water samples were analyzed with ion-exchange chromatography using a Dionex device with a CS 12A separation column. The method detection limit determined according to the definition of the US Envirinmental Protection Agency amounted to 0.009 microg l(-1).

Chromatography, Liquid↗
PubMed1988

Diagnosis related groups, resource utilization, age, and outcome for hospitalized nephrology patients.

Economic incentives are rapidly changing for hospitals under the prospective Diagnosis Related Group (DRG) hospital reimbursement scheme. The purpose of this project was to study resource use, age, and outcome for nephrology admissions to a large academic medical center. Total hospital costs for the 784 nephrology admissions (January 1, 1985 to December 31, 1986) were $5,037,460. Mean hospital cost per patient and mortality generally increased with age. DRG payment for patients in the 13 nephrology DRGs analyzed would have produced an aggregate loss of $483,584; however, all age categories of patients 55 years of age and over generated significant losses (the highest was for patients 85 years and above, $5,343 loss per patient). Diabetic nephrology patients generated greater resource consumption compared with nondiabetic nephrology patients, as well as patients in medical and surgical DRGs with chronic renal failure compared with patients in these same DRGs without chronic renal failure. Older nephrology patients also demonstrated higher emergency and ICU admission and blood requirements than younger patients. This study suggests that the current DRG reimbursement scheme may be inequitable vis a vis older nephrology patients, as well as those with diabetes mellitus and chronic renal failure. Financial disincentives by DRGs may affect both the access and quality of care for groups of nephrology patients in the future.

Adolescent↗
PubMed1983

Inhibition of amino acid transport by cis-diamminedichloroplatinum(II) derivatives in L1210 murine leukemia cells.

The uptake of cis-diamminedichloroplatinum(II) (cisplatin) has been studied in the L1210 murine lymphoid leukemia cell line. Labeled cisplatin and its aquated derivatives were resolved by high-performance liquid chromatography on a strong cationic exchange column. After 10 min of incubation of cisplatin with the cells, the major portion of the non-protein-bound platinum was in the form of cisplatin. However, a portion of this platinum was converted with time to a derivative which coeluted with the monoaquo derivative of cisplatin. With the appearance of this derivative, there was a concomitant inhibition of sodium-dependent amino acid transport as measured by the uptake of aminoisobutyric acid and methionine. Furthermore, the exposure of L1210 cells to a preparation of predominantly aquated product(s) of cisplatin inhibited amino acid uptake following a brief (2-min) incubation, whereas measurable inhibition of amino acid uptake by cisplatin required a longer preincubation period. This inhibition of aminoisobutyric acid and methionine was dependent on the concentration of platinum. Aminoisobutyric acid and methionine were shown to be concentrated in L1210 cells in the presence of sodium ions, and competition experiments suggest similar uptake systems. Since L1210 cells are methionine-auxotrophic leukemic cells, inhibition of essential amino acid transport by cisplatin may be a mechanism of cytotoxic action.

Aminoisobutyric Acids↗