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Biomedical subjects

J Vymazal

Publications and source records attributed to J Vymazal.

At least 19 recordsLinked to original sources

T1 and T2 of ferritin at different field strengths: effect on MRI.

Nuclear magnetic relaxation times T1 and T2 were measured in ferritin solutions at field strengths from 0.04 to 1.5 T. T1 was relatively constant, but 1/T2 increased linearly with field strength, in agreement with earlier MRI observations in the monkey brain. This finding supports the theory that ferritin is responsible for T2 shortening in brain nuclei containing iron. The linear dependence of 1/T2 on magnetic field is unique and not explained by present theories of the magnetic properties of ferritin.

Animals

[The most frequent localization of cerebral ischemia attacks. III. Status lacunaris cerebri].

The initial two parts of a 3-volume study on cerebral ictus concerned with analysis of macroangiopathic ischaemic defects are concluded with a final study analyzing microangiopathic defects. In a group of 93 patients with status lacunaris cerebri, the authors evaluated the presence and morphology of three main manifestations of status lacunaris: cerebral atrophy (periventricular and cortical), subcortical arteriosclerotic encephalopathy and the position of cerebral lacunae. The cerebral lacunae were mostly localized at the interphase of the individual cerebrovascular systems, which shows that their pathogenesis was due to interterritorial infarct.

Atrophy

[Lipids in serum and cerebrospinal fluid in acute cerebrovascular disorders].

The cholesterol and lipoid phosphorus levels in the serum and liquor' cerebrospinalis were studied in 40 patients suffering from ischaemic cerebral lesions. A chromatographic determination was also performed for eight sub-fractions of polar and neutral fats (lysolecithin, sphingomyelin, lecithin, phosphatidyl-ethanolamine, non-esterified fatty acids, cholesterol, triglyceride and cholesterol ester). Furthermore, five sub-fractions of cholesterol esters were prepared according to the degree of unsaturation in the individual fatty acids. The results were compared with a group of 25 control persons. No significant changes in the lipide sub-fractions were found in the serum. Total cholesterol was lower for cerebral haemorrhages, lipoid phosphorus was higher. In the liquor, no increase was found in total lipides but only a shift in some lipide fractions, the most pronounced being a lowering in triglyceride and an increase in free cholesterol and sphingomyelin. It would seem that a determination of lipides in the serum and liquor is not decisive for the diagnosis of acute vascular cerebral haemorrhages. These questions require thorough research and experimentation.

Acute Disease