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Biomedical subjects

G Steiner

Publications and source records attributed to G Steiner.

At least 325 records · Page 18Linked to original sources
PubMed1965

Serum and urinary enzyme activity after renal infarction.

Recently it has been observed that the activity of certain enzymes in serum and urine may be increased after renal infarction. Although aortography or selective renal angiography should be the diagnostic corner-stone on which one would proceed to embolectomy, it is possible that enzyme assays may serve as laboratory aids to suggest or confirm the diagnosis. This paper reviews the few existing clinical and experimental studies and reports on two patients who had a total of three episodes of renal infarction. Serial determinations after one episode showed increased activity of serum oxaloacetic glutamic transaminase (SGOT) and of lactic acid dehydrogenase (LDH) and alkaline phosphatase in the serum and urine; some elevated serum LDH and SGOT values were recorded after the other two infarctions. The time of onset and duration of these increases are discussed, and the possible difficulty in differentiating renal from myocardial infarction is illustrated.

Aged↗
PubMedDate not supplied

Glutathione peroxidase and glutathione S-transferase activity of platelets.

A low Se intake in dietetically treated patients with phenylketonuria (PKU) or maple syrup urine disease (MSUD) leads to a marked reduction of the platelet glutathione peroxidase activity (GSHPx). The mean value amounted to 2.0 U/10(11) platelets with t-butyl hydroperoxidase (t-BOOH) (2.2 U/10(11) with H2O2) in patients and 5.8 U/10(11) with t-BOOH (5.4 U/10(11) with H2O2) in the control children. After Se supplementation with yeast rich in Se (dose: 135 micrograms Se/m2) the GSHPx activities rapidly increased. They reached a plateau after 2-3 weeks and remained there during the following 15-20 weeks of supplementation. After the cessation of supplementation there was a slow decrease, the values reached a low plateau after 24 weeks. In addition platelet glutathione S-transferase (GSHTf) was estimated with 1-chloro-2,4-dinitrobenzene. No significant difference between the values in healthy and dietetically treated patients in a low or normal Se state was observed. GSHTf did not exhibit peroxidase activity and did not show a compensatory increase when Se dependent GSHPx activity was low. The patients do not reveal clinical signs of disturbed platelet function. GSHPx may act in platelets via lipoxygenase on the prostaglandin pathway. The physiologic consequence of altered arachidonate metabolism, when GSHPx is deficient in platelets, remains to be elucidated.

Blood Platelets↗
PubMedDate not supplied

Infrared and Raman imaging of biological and biomimetic samples.

Established methods for imaging of biological or biomimetic samples, such as fluorescence and optical microscopy, magnetic resonance imaging (MRI), X-ray tomography or positron emission tomography (PET) are currently complemented by infrared (both near-IR and mid-IR) as well as Raman spectroscopic imaging, whether it be on a microscopic or macroscopic scale. These vibrational spectroscopic techniques provide a wealth of information without a priori knowledge of either the spectral data or the composition of the sample. Infrared radiation does not harm the organism, no electric potential needs to be applied, and the measurements are not influenced by electromagnetic fields. In addition, no extrinsic labeling or staining, which may perturb the system under investigation, has to be added. The immense volume of information contained in spectroscopic images requires multivariate analysis methodologies in order to effectively mine the chemical and spatial information contained within the data as well as to analyze a time-series of images in order to reveal the origin of a chemical or biochemical process. The promise and limitations of this new analytical tool are surveyed in this review.

Animals↗