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Biomedical subjects

K Herzog

Publications and source records attributed to K Herzog.

12 recordsLinked to original sources
PubMed1994

Structure of hydrated layers on silicate electrode glasses.

The structural changes of the silicate framework in hydrated layers of silicate electrode glasses compared with untreated glasses as well as the quality and quantity of water and its ionic species stored in the layer have been investigated by high-resolution solid-state nuclear magnetic resonance (NMR) techniques [29Si magic-angle spinning (MAS), 29Si cross-polarization (CP) MAS, 1H high-speed MAS, 1H CRAMPS and 1H Echo NMR]. To support the results, infrared (IR) spectroscopy, thermal analysis and sodium ion concentration analyses were used. It was found that at least two different water species exist in the hydrated layer: SiOH groups and not very mobile hydrogen-bonded molecular water. Concerning the framework modified, Q3 groups [(SiO)3SiOH] were formed in the hydrated glass. During the swelling process a condensation of silanol groups formed took place to a great extent.

Electrodes↗
PubMed1988

[Diagnostic value of aspartate aminotransferase in the cerebrospinal fluid].

As datum, the range of aspartate aminotransferase in the cerebrospinal fluid of adults was determined on the basis of 153 fluid samples and compared with the values obtained from 356 neurological patients. A significant increase in enzyme activity was established in respect of CVI, polyneuropathy, acute encephalitis, and SAB. It was possible to eliminate any dependence of the aspartate aminotransferase activity on serum activity, total protein, and cell count. The increase in activity of aspartate aminotransferase in the cerebrospinal fluid is thus identified as an independent pathological fact, and thus it can be incorporated in diagnostic routine more particularly in the diagnosis of CVI disorders.

Aspartate Aminotransferases↗
PubMed1981

[Changes in circulatory parameters in dogs under general respiratory hypoxia].

The decrease in the oxygen content of the inspired air calls forth enhanced demands on the cardiocirculatory performance. In experiments on healthy dogs the haemodynamic shifts connected with short-term hypoxia were investigated, with particular attention to the possible presence of irreversible changes in the myocardium. With the aid of radiocardiography the following parameters were investigated before, during and after hypoxic test: blood volume, cardiac output, stroke volume, heart frequency, ejection fraction, mean right-to-left circulation time, and segmental lung volume. In dependence on the degree of hypoxia characteristic changes in the above parameters occurred. After the end of hypoxia most parameters returned to their initial levels. The presence of irreversible changes could not be proved. Under the given conditions, it was possible to test the individual level of cardiocirculatory performance with the aid of hypoxia similarly as by using the exercise test.

Animals↗
PubMed1978

Mature placenta simulating fetus papyraceus on ultrasonic examination.

A case of a heavily calcified, mature placenta simulating the appearance of a fetus papyraceus is presented. Calcification surrounding the more sonolucent cotyledons simulated the body and limbs of a dead fetus. Awareness of the morphologic alterations which occur as the placenta matures should prevent confusion of normal placental changes with a pathologic entity.

Calcinosis↗
PubMedDate not supplied

CT and MR evaluation of intracranial involvement in pediatric HIV infection: a clinical-imaging correlation.

PURPOSE: To review the cranial CT and MR examinations of 29 children with perinatally transmitted HIV infection and correlate the imaging findings with clinical and pathologic data. METHODS: 28 children were examined with CT, four with MR. RESULTS: CT abnormalities were seen in 25 children studied (89%), including cerebral atrophy (25 children), basal ganglia calcification (10 children), periventricular frontal white matter calcification (four children), cerebellar calcification (one child), white matter low attenuation areas (two children), intracranial hemorrhage (three children) and cerebral infarction (one child). Intracranial calcifications were only seen in association with cerebral atrophy and were never seen prior to 1 year of age. Calcifications in the periventricular white matter or cerebellum were always associated with basal ganglia calcifications. MR abnormalities were seen in all four children studied; cerebral atrophy (four children), areas of high signal intensity in white matter (four children), loss of normal posterior pituitary high signal intensity (one child). Cerebral atrophy appeared to be a nonspecific finding that was seen in some children in the absence of neurologic signs and symptoms. All children with intracranial calcifications had developmental delay. Intracranial hemorrhage was seen in children with severe thrombocytopenia. Focal intracranial infections were unusual and neoplastic lesions were not found. CONCLUSIONS: Cerebral atrophy, basal ganglia calcifications, and focal white matter lesions were the most common abnormalities seen neuroradiologically in our series of HIV-infected children; cerebral atrophy was a nonspecific finding.

Atrophy↗