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Biomedical subjects

C Hoffmann

Publications and source records attributed to C Hoffmann.

At least 19 recordsLinked to original sources
PubMed1995

Acquired von Willebrand disease in malignant peripheral neuroectodermal tumor (PNET).

In week 12 of the EICESS 92 protocol a 12-year-old boy with pelvic PNET developed acquired von Willebrand disease: bleeding time was prolonged (> 15 min) and von Willebrand factor antigen (54%) and ristocetin cofactor activity (50) were reduced. Platelet aggregations with thrombin and collagen and the number of major platelet glycoproteins/per platelet did not differ from the controls. After Haemate P (Behring Werke, Marburg, Germany) bleeding time normalized and surgery could be performed without occurrence of bleeding episodes. Three weeks after surgery bleeding time, ristocetin cofactor activity, and von Willebrand factor antigen increased to normal paediatric values. Without occurrence of further bleeding episodes the patient received another 10 courses of polychemotherapy (EICESS 92).

Bone Neoplasms↗
PubMed1995

Nitric oxide mediates microvascular permeability in the isolated perfused rat mesentery?

The permeability influencing effect of nitric oxide was studied by means of an isolated perfused mesentery preparation in combination with a intravital/fluorescence microscopic set up. As a fluorescent marker served FITC-dextran mol wt 70,000 daltons. Tissue treatment was performed by application of NO-donors like SNP or GTN. Additionally the effects of bradykinin, L-nitroarginine or the combination of both were tested in regard to a permeability modulation. The results point out that NO-donors did not enhance microvascular permeability, whereas the permeability increasing effect of bradykinin is mediated by an NO-independent pathway.

Animals↗
PubMed1995

[The magnetic resonance tomography of Ewing's sarcomas: the morphology and tumor extension].

PURPOSE: The morphology and delineation of Ewing sarcoma in magnetic resonance imaging was investigated. METHODS AND MATERIALS: Magnetic resonance images (spin-echo techniques; T1-w pre/post gadolinium, T2-w) of 59 patients as part of a multicenter study were evaluated retrospectively. Qualitative image analysis was performed: signal intensity (point of reference extraosseous: muscle, intraosseous: bone marrow), enhancement patterns, lesion delineation and differentiation between tumor and oedema. RESULTS: Signal intensity: T1-w: extraosseous: 75% isointense, intraosseous: 92% hypointense; T2-w extraosseous: 100% hyperintense, intraosseous: 93% hyperintense. Enhancement pattern: 97% both extra- and intraosseous. Best delineation intraosseous in T1-w (53% good, 36% very good), extraosseous in gadolinium enhanced T1-w (46% good, 37% very good) and T2-w (55% good, 33% very good). Differentiation between tumour and oedema was intraosseous not possible, extraosseous in T2-w in 61%. CONCLUSION: Morphology of Ewing sarcoma in magnetic resonance imaging is rather uniform. The lesion is intra- and extraosseous sharply delineated, though tumour and oedema can be rarely differentiated.

Adolescent↗
PubMed1995

Comparative bioavailability of metronidazole formulations (Vagimid) after oral and vaginal administration.

Bioavailability of Vagimid 500 tablets (film coated, 500 mg metronidazole) and absorption of metronidazole into the systemic circulation after vaginal administration of Vagimid vaginal tablets (100 mg metronidazole) relative to respective listed references were studied in 16 female healthy volunteers (age 21-37 years, weight 45-67 kg, height 158-179 cm). Metronidazole and its main hydroxylated metabolite were measured using an HPLC-method with detection limits of 0.025 and 0.25 micrograms/ml (for vaginal and oral studies), respectively. Extent of absorption was assessed by AUC0-infinity (bioequivalence range 0.80-1.25), rate of absorption by Cmax/AUC0-infinity (bioequivalence range 0.70-1.43). Geometric means and 90%-confidence intervals of the ratios of these primary characteristics were calculated using a multiplicative model. Vagimid 500 tablets were bioequivalent to the reference formulation with regard to extent and rate of absorption of metronidazole because of AUC0-infinity = 0.995 (0.84-1.18) and Cmax/AUC0-infinity = 1.11 (0.94-1.30). The absorption of metronidazole into the systemic circulation after vaginal administration of Vagimid vaginal tablets caused maximal serum concentrations between 433 and 1,156 ng/ml after 8-20 h which are bactericidal only for the most susceptible anaerobic germs and which are most likely only of marginal importance for drug safety.

Absorption↗
PubMed1995

[Subjective evaluation criteria in psychiatric care--methods of assessment for research and general practice].

Evaluation of psychiatric care is an important task in research and in routine conditions. It requires definition of criteria. Subjective criteria are, for different reasons, of increasing interest. Subjective quality of life, subjective needs for help and support and patients' assessment of psychiatric treatment are regarded as particularly relevant criteria. We present and briefly discuss instruments for assessment of these criteria, that are new at least in the German language. Results of a first cross-sectional study in a community care setting are reported. Regarding quality of life healthy groups were examined too. The findings suggest that the instruments are usefully applicable and that they may produce plausible results.

Adult↗
PubMed1994

Effects of acidosis and alkalosis on mechanical properties of hypertrophied rat heart fiber bundles.

Effects of alkalosis (pH 7.4) or acidosis (pH 6.8) on the intrinsic mechanical properties of control and pressure-overloaded rat hearts were studied in Triton X-100-treated left ventricular fiber bundles. In control bundles, Ca sensitivity [pCa required for one-half maximal response (pCa50)] was 5.520 +/- 0.012 at pH 7.1. Alkalosis increased it by 0.357 +/- 0.018 pCa unit, whereas acidosis decreased it by 0.365 +/- 0.014 pCa unit with no change in Hill coefficient. Maximal tension was decreased by acidic pH and increased by alkaline pH. Stiffness was measured by the response to quick length changes. Acidosis decreased maximal stiffness but increased the stiffness-to-force ratio, whereas alkalosis increased maximal stiffness but had no effect on stiffness-to-force ratio, suggesting that acidosis decreased the force generated per cross bridge. Alkalosis increased the time constant of tension recovery following a quick stretch from 10.6 +/- 0.66 to 17.45 +/- 1.83 ms, suggesting a decreased cross-bridge cycling rate. Pressure overload induced by thoracic aortic stenosis for 4-6 wk led to a 200% cardiac hypertrophy associated with a shift from fast to slow ventricular myosin. pCa50 of hypertrophied bundles was not different from control (5.541 +/- 0.012). Ca sensitivity was increased by 0.383 +/- 0.008 in alkaline medium and decreased by 0.325 +/- 0.009 in acidic medium. Stiffness-to-force ratio was decreased in acidic pH, and the time constant of tension recovery was increased from 31.0 +/- 0.4 to 34.9 +/- 0.25 ms by alkalosis. In hypertrophied bundles, maximal tension was decreased by acidic pH but not changed by alkalosis. These results show that in the small pH range of our study 1) pH changes have symmetrical effects on Ca sensitivity in both control and hypertrophied bundles, 2) a decrease or an increase in H+ concentration does not have symmetrical effects on the mechanics of the cross bridges, and 3) changes in the phenotype of contractile proteins induced by aortic stenosis do not influence Ca sensitivity, only moderately influence the response to pH changes, and mainly affect the cross-bridge cycling rate.

Acidosis↗
PubMed1993

[Initial findings using dynamic magnetic resonance tomography in the diagnosis of inflammatory diseases of the sacroiliac joint].

Up to now 42 patients with clinically suspected diagnosis of sacroiliitis (including 19 patients with confirmed spondylitis ankylosans) and 12 healthy volunteers were examined via magnetic resonance tomography. In oblique sections parallel to the plane of the sacrum the signal intensity patterns from normal and pathological tissues of the sacroiliac articulations were evaluated by plain T1-weighted spin-echo sequences and T2*-weighted FLASH sequences. In addition we used a dynamic FLASH measurement following intravenous application of gadolinium-DTPA for quantitative calculation of signal-time courses. This method has proved to be capable of definitely differentiating normal findings of sacroiliac articulations from inflammatory changes (p = 0.0001) and also enables quantification of the inflammatory activity.

Adult↗
PubMed1993

Mechanical properties of rat cardiac skinned fibers are altered by chronic growth hormone hypersecretion.

Chronic growth hormone (GH) hypersecretion in rats leads to increased isometric force without affecting the unloaded shortening velocity of isolated cardiac papillary muscles, despite a marked isomyosin shift toward V3. To determine if alterations occurred at the level of the contractile proteins in rats bearing a GH-secreting tumor (GH rats), we examined the mechanical properties of skinned fibers to eliminate the early steps of the excitation-contraction coupling mechanism. We found that maximal active tension and stiffness at saturating calcium concentrations (pCa 4.5) were markedly higher in GH rats than in control rats (tension, 52.9 +/- 5.2 versus 38.1 +/- 4.6 mN.mm-2, p < 0.05; stiffness, 1,105 +/- 120 versus 685 +/- 88 mN.mm-2.microns-1, p < 0.01), whereas values at low calcium concentrations (pCa 9) were unchanged. In addition, the calcium sensitivity of the contractile proteins was slightly but significantly higher in GH rats than in control rats (delta pCa 0.04, p < 0.001). The crossbridge cycling rate, reflected by the response to quick length changes, was lower in GH rats than in control rats (62.0 +/- 2.6 versus 77.4 +/- 6.6 sec-1, p < 0.05), in good agreement with a decrease in the proportion of alpha-myosin heavy chains in the corresponding papillary muscles (45.5 +/- 2.0% versus 94.6 +/- 2.4%, p < 0.001). The changes in myosin heavy chain protein phenotype were paralleled by similar changes of the corresponding mRNAs, indicating that the latter occurred mainly at a pretranslational level. These results demonstrate that during chronic GH hypersecretion in rats, alterations at the myofibrillar level contribute to the increase in myocardial contractility observed in intact muscle.

Animals↗
PubMed1991

[Clinical pharmacokinetics of lidocaine after intraoral nerve block].

Aim of this study was to show the time course of plasma concentrations of 2% lignocaine with adrenalin at a concentration of 1:100,000. Four retinated third molars were removed in one session in 23 patients. For local anaesthesia in each patient we used 10 ml of Xylocaine 2% (Astra), which is commonly used in dentistry. The plasma-concentration was measured for the first 30 minutes after injection of the local anaesthetic using high pressure liquid chromatography (HPLC). Our results suggest that partially intravascular injection could not be avoided although careful aspiration was carried out before injecting. Neither subjective nor objective adverse central nervous effects were seen in our patients. Nevertheless we consider a peripheral intravenous cannula and ECG-monitoring strongly recommended in all major operations under local anaesthesia.

Adolescent↗
PubMed1991

[Mycological surveillance of children with cystic fibrosis].

The mycological surveillance included 121 patients aged 1 to 21 years treated from 1981 to 1987 in the Centre of Cystic Fibrosis in Dresden. The control groups comprised 136 resp. 140 healthy children aged 1 to 16 years. The study evaluated the incidence of fungi in the oral cavity, bronchial secreta, sputum, faeces and urine as well as the specific serum antibodies to Candida albicans and Aspergillus fumigatus in correlation to the course of the cystic fibrosis and the applied chemotherapy. The study pointed out a parallel run concerning the progression of the clinical manifestation of the basic disease, the duration of the required chemotherapy and the mycological findings indicating more and more pathological levels. The mycological results of the children with a moderate course of cystic fibrosis were conformable to the findings of the children of the control groups. Systemic candidosis or aspergillosis were not seen. Because patients suffering from cystic fibrosis are predisposed for infections with fungi, especially with Aspergillus fumigatus, the authors recommend a mycological surveillance of these patients depending on the clinical course of cystic fibrosis: once in twelve months for patients with mild symptoms and every third month for patients with severe symptoms.

Adolescent↗
PubMed1990

The craniodigital syndrome of Scott: report of a second family.

We report on a boy with a characteristic combination of facial anomalies, syndactylies of fingers and toes, and mental retardation. Scott et al. (Journal of Pediatrics 78:658-663, 1971) observed 3 brothers with almost identical manifestations. The mother of these patients had bilateral syndactyly of toes 2 and 3. This led the authors to suggest X-linked inheritance. The mother of our patient also has cutaneous syndactyly between the second and third toes, strengthening the hypothesis of X-linked inheritance.

Face↗
PubMed1990

Flow cytometric analysis of G1- and G2/M-phase subpopulations in mammalian cell nuclei using side scatter and DNA content measurements.

Several subcompartments of the cell cycle in addition to the G1-, S-, and G2-phases usually observed were identified by simultaneous flow cytometric measurements of ethidium bromide fluorescence and side scatter intensity of cell nuclei. Metaphase cells and very early G1-phase cells (G1A) with low side scatter intensities were discriminated from interphase cells with high side scatter intensities. The reason for the various side scatter intensities was found to be the different structure of metaphase cells and early G1-phase cells due to chromatin condensation as shown by sorting of the respective cell nuclei. The G1A-phase could further be subdivided into two compartments with very low side scatter (G1A1) and intermediate side scatter (G1A2) intensities. Using partially synchronized cells the duration of these subcompartments of the G1-phase could be estimated. The durations of G1A1- and G1A2-phases were found to be about 10 min and 20 min, respectively, compared to the total duration of the G1-phase of about 3 h. Additional flow cytometric measurements of side scatter intensities of cell nuclei provide therefore further information on subcompartments of the G1- and G2/M-phases.

Animals↗
PubMed1990

Pediatric bone marrow transplants: psychological aspects.

On a pediatric bone marrow transplant unit, hematologist-oncologists, nurses, social workers, psychiatrists, psychologists, and others on the team deal with children and adolescents whose cancers are either treatable by marrow transplantation or are ultimately fatal. Contrary to original assumptions, many children and families cope well, especially in relatively uncomplicated cases with good outcome. Treatment may include direct psychotherapeutic intervention with the child and family, as well as use of psychopharmacologic agents such as antidepressants or anxiolytics for frank psychiatric disorders. Psychotherapists often have to function adjunctively with other staff members in their interactions with the patient and the family. A stress disorder model appears to best explain child, parent and family reactions to bone marrow transplantation. Given the medical severity and complexity of the conditions treated, and the approximately equal rates of overall success and failure, a supportive consultative approach is usually most helpful for child patients, parents and staff throughout the procedure. A retrospective study of the children treated over seven years in a tertiary pediatric hospital bone marrow transplant unit is presented. The level of child, parent, and family psychopathology was usually mild to moderate, but there were clear differences between patients. Mothers were more supportive than fathers under this extreme type of stress. Prospective longitudinal studies of children and families are needed to establish causal chains and optimal therapeutic interventions.

Adaptation, Psychological↗
PubMed1990

[Chemical and thermal compatibility of all-ceramic systems].

The chemical and thermal compatibility of the all-ceramic systems Vitadur-N, Hi-Ceram and In-Ceram as well as the combinations of Dicor with Vitadur-N, Dicor with NBK 1000 and Dicor with Vivodent, respectively, were investigated by means of electronmicroscopy and microprobe measurements at the interface of each compound, and thermomechanical analyses of the components were performed. The results show good contact at the interface of all combinations investigated. No evidence was found for diffusion at the interface except in the In-Ceram system, were a migration of K+ from Vitadur-N dentine into the glassy phase of In-Ceram occurs. The thermomechanical analyses showed a good thermal compatibility of all compounds investigated.

Biocompatible Materials↗