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Biomedical subjects

K Herzog

Publications and source records attributed to K Herzog.

18 recordsLinked to original sources

Internet-assisted exercises in structural analysis.

In this report we describe our experience in the analytical chemistry curriculum of teaching spectrometer principles and preparing spectroscopy laboratory exercises by means of virtual instruments. The benefits of the intensified preparation of laboratory exercises by virtual instruments will be evaluated with respect to the subsequent handling of real instruments. The utilization of in-house electronic media with Internet resources for elucidation and verification of a structural assignment will also be considered.

Journal Article↗

Antibodies against recombinant heat shock protein 65 of Tropheryma whipplei in patients with and without Whipple's disease.

Tropheryma whipplei is the causative agent of Whipple's disease (WD), a chronic, life-threatening infection. Laboratory diagnosis is mainly based on PCR and histopathological analysis in duodenal biopsies and other specimens requiring invasive procedures. We have examined the presence of antibodies to recombinant heat shock protein (Hsp65) of T. whipplei in patients with Whipple's disease as well as in control subjects by Western blot and enzyme-linked immunosorbent assay (ELISA). A recombinant plasmid carrying the entire T. whipplei hsp65 gene was constructed, and the expression yielded a 65-kDa histidine-tagged protein. Among four patients with Whipple's disease, two showed an IgG- and one an IgA-response, respectively, when analyzed by Western blotting, whereas from 10 patients without Whipple's disease, only two patients showed a positive IgG-response. The differences between the sera from patients and controls were thus not significant. Successful purification of the protein was achieved by Ni-NTA affinity chromatography. Quantitative analysis of serum antibodies by ELISA demonstrated that antibody levels in the sera of 14 patients were not significantly higher than in those of 89 control subjects. The established ELISA test is not useful to clinical diagnostics.

Actinobacteria↗

Experience with the osteocutaneous fibula flap: an analysis of 24 consecutive reconstructions of composite mandibular defects.

Based on findings from anatomical dissections of the skin of the peroneal artery, we used the osteocutaneous fibula flap for combined replacement of the mandible and floor of the mouth in 24 patients, form November 1993 to December 1995. There were 22 primary and 2 secondary reconstructions; the mean age of the patients (2 women and 22 men) was 64 years. The length of the fibula segments ranged between 5.5 and 18 cm, the size of the skin component between 3 x 5 and 6 x 15 cm. Corresponding to the results of our anatomical studies, the skin island was exclusively raised form the distal third of the lower leg, and the donor sites were generally covered with split thickness skin grafts. The average length of the dissected vascular pedicle was 11 cm, so that a vein graft was only required in one case. Flap raising and tumour resection were always carried out simultaneously. Fibula osteosynthesis was done with titanium miniplates; the insertion of endosseous implants followed secondarily. The success rate was 95.8% with one transplant loss and pseudarthrosis in one case. Despite the limited width of the fibula, the shape of the mandible was satisfactorily reconstructed in all patients, and the thin, pliable component enabled intraoral coverage with only negligible surplus volume. Chronic wound-healing disturbances at the donor site of the skin island occurred in two cases; impairment of walking ability was not detected. According to our experience, the use of the osteocutaneous fibula flap is a valuable method for the reconstruction of composite mandibular defects.

Adult↗

Gallbladder adenocarcinoma and acalculous chronic lymphoplasmacytic cholecystitis associated with ulcerative colitis [corrected].

Patients with ulcerative colitis, particularly long-standing ulcerative pancolitis, have an increased risk of developing carcinoma of the hepatobiliary tract. However, only 14 cases of carcinomas localized to the gallbladder have been associated with ulcerative colitis. Of 57 cases of gallbladder carcinomas seen at this institution, we found 3 cases in patients with ulcerative colitis, all of whom had undergone total proctocolectomy. All three patients had pancolitis, two with high-grade dysplasia, and one with low-grade dysplasia. All three gallbladders harbored an invasive adenocarcinoma. The nonneoplastic gallbladder mucosa showed a background of acalculous chronic lymphoplasmacytic cholecystitis in two cases. One of these patients also had a liver biopsy which showed changes of primary sclerosing cholangitis. Because cholecystectomy adds little to the operative morbidity and mortality of total proctocolectomy, it might be advisable to perform both operations when the latter is indicated for high-grade dysplasia in ulcerative colitis.

Adenocarcinoma↗

Detection of multiple boron sites in glasses by 11B satellite transition nuclear magnetic resonance spectroscopy.

The magic-angle spinning sidebands of the satellite transition (ST, m = +/- 3/2 <==> +/- 1/2) for 11B nuclear magnetic resonance (11B ST spectroscopy) have been used to detect multiple boron sites in Na2O-B2O3-SiO2 glasses. The experimental details and data analysis are described, how multiple BO4 and BO3 units can be distinguished using standard magic-angle spinning. For a 16Na2O-30B2O3-53.9SiO2 glass (0.1 MnO) two BO4 units with chemical shifts of -2.5 and 0 ppm were found which differ considerably in their quadrupole interaction. Besides this we found three different BO3 units with approximate chemical shifts of 17, 15, and 19 ppm. The results are compared with earlier measurements.

Boron↗

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↗

[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↗

[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↗

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↗

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↗