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Biomedical subjects

A Schmidt

Publications and source records attributed to A Schmidt.

At least 325 records · Page 18Linked to original sources
PubMed1995

Quantification of mitral regurgitation--comparison of the proximal flow convergence method and the jet area method.

A total of 92 patients with mitral regurgitation (age 63 +/- 13 years, 51 men, 41 women), quantified by angiography, were studied using color-flow Doppler imaging of isovelocity surface areas in the flow convergence region proximal to the regurgitant orifice (PISAs) and of the regurgitant jet in the left atrium. The PISA radii for the flow velocities (aliasing borders) of 28 and 41 cm/s, jet area, jet length, and relation of jet area to left atrial area were measured. A proximal flow convergence region was imaged in 98% (85%) of all patients for a flow velocity of 28 (41) cm/s. A regurgitant jet could be visualized in all patients. The PISA radii for both flow velocities correlated more closely with the angiographic grade (rSp = 0.79 for both flow velocities) than the jet area (rSp = 0.43), jet length (rSp = 0.39), and relation of jet area to left atrial area (rSp = 0.37). A correct differentiation of grade I-II from grade III-IV mitral regurgitation was provided in 95% of the patients by the proximal flow convergence method for both flow velocities and in up to 78% of the patients by the jet area method using the uncorrected jet area. The PISA radii correlated weakly with the parameters from the regurgitant jet (r = 0.5-0.58). It can be concluded that the proximal flow convergence method and the jet area method reach comparable sensitivity for the detection of mitral regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Sarcomatoid carcinoma of the bladder in a 25-year-old man].

A 25-year-old patient with a rapidly growing sarcomatoid carcinoma of the urinary bladder is reported. The diagnosis was made on the basis of extended atypical proliferations of spindle or pleomorphic cells in the area of pelvic floor and the radix of the penis. The tumor showed invasion of the blood and a high Ki-67 growth fraction up to 40%. Immunohistochemically, the reactions with antibodies against cytokeratin, EMA, and vimentin were positive, while negative results were obtained in reactions with antibodies against desmin, actin, PSA, S 100, human epithelial antigen (Ber-EP4), and cytokeratin 13. The differential diagnosis against myosarcomas, pseudosarcomatous lesions, and inflammatory pseudotumours is discussed. After radical surgery a pelvic recurrence and pulmonary metastases developed, which led to the patient's death 3 months later. This case shows that sarcomatoid carcinomas of the urinary bladder can be found even in young people.

Adult↗
PubMed1995

Misrouting of tyrosinase with a truncated cytoplasmic tail as a result of the murine platinum (cp) mutation.

Mice homozygous for the platinum (cp) allele at the albino locus manifest severe oculocutaneous albinism despite the presence in vitro of tyrosinase activity at 25% wild-type levels. We demonstrate that the cp allele results from an A-->T substitution, changing a lysine residue at position 489 to a termination codon, with truncation of tyrosinase's cytoplasmic tail. In choroidal melanocytes of neonatal mutant mice, tyrosinase activity could be detected in the trans Golgi network, but was absent from melanosomes. Instead, it was detected in vesicles in the cell periphery and dendrites, and on the extracellular surface. In the retinal pigment epithelium, activity was present on the extracellular apical and basolateral surfaces. Our results demonstrate misrouting of a mutant tyrosinase lacking its cytoplasmic tail, providing an explanation for the severe effect of this mutation on ocular and cutaneous pigmentation.

Albinism, Oculocutaneous↗
PubMed1995

Rectal suction biopsy: can it be sufficient to diagnose neuronal intestinal dysplasia?

Rectal suction biopsy is the diagnostic procedure of choice in aganglionosis even if only mucosal tissue is obtained. In neuronal intestinal dysplasia it is essential to include parts of the submucous layer. Therefore some biopsies are unsuitable because they lack submucous tissue. In a retrospective analysis (1991-1993) this occurred in 34.9% of our biopsies. These samples were taken without attention to the level of suction. Prospectively we compared suction biopsies taken by a standard suction level (250-300 cm water column) with excision biopsies taken by scissors under speculum exposure in ten consecutive patients. Submucosa was missed in only one biopsy each, but two excision biopsies were made useless by mechanical traumatization. We conclude a correctly practised rectal suction biopsy still remains the procedure of choice for diagnostic screening in malformations of the enteric nervous system.

Biopsy↗
PubMed1995

The Dornier Lithotripter U 30: first clinical experience.

Since August 1993, the Dornier Lithotripter U 30 has been used at the Department of Urology of the Katharinenhospital in Stuttgart. The machine consists of an endourologic table with an X-ray unit mounted on a C-arm and an electromagnetic shockwave source equipped with an inline ultrasound scanner and oblique shockwave coupling with a water cushion. Stone location can be performed with fluoroscopy or simultaneous ultrasound scanning. Until December 1994, 1092 stones had been treated, requiring 1533 sessions: 497 stones (45.5%) were situated in a calix, 426 (39%) in the renal pelvis, 130 (11.9%) in the upper ureter, and 39 (3.6%) in the distal ureter. Auxiliary measures were necessary before SWL in 245 patients (16%): double-J stent placement in 184 patients (12%), percutaneous lithotripsy in 43 patients (2.8%), and percutaneous nephrostomy in 15 patients (1%). The mean number of shockwaves was 3018, ranging from 250 to 3750. The time needed for positioning ranged from 1 to 10 minutes (mean 3 minutes). The mean treatment time was 30.5 minutes (range 10-50 minutes). There were 26 treatments (1.7%) performed without analgetic medication. In 1359 cases (88.6%), analgetics were utilized, and in 108 cases (7.0%), a sedative was added. In 40 patients (2.6%), general anesthesia was necessary. Complete stone disintegration was achieved in 94%. Auxiliary measures after SWL were ureteroscopy in 8.4% and percutaneous nephrostomy in 1.3%. Perirenal hematomas were found in 10 patients (0.6%). Colic pain necessitating analgetic medication was reported by 247 patients (16.1%). Body temperature above 38 degrees C occurred after 20 treatments (1.3%). At 3 months' follow-up, 110 patients of 128 patients (85.9%) were stone free. The Dornier Lithotripter U 30 has proven highly effective for SWL of renal and ureteral stones, radiolucent and radiopaque, and can be used as a full endourologic work-station.

Follow-Up Studies↗
PubMed1995

Occupational contact dermatitis in bakers, confectioners and cooks. A population-based study.

A population-based study was performed to investigate incidence rates of occupational skin disease (OSD) in bakers, confectioners and cooks, as well as the rôle of endogenous and exogenous risk factors. In North Bavaria, all closed cases of OSD were recorded systematically in a 3-year period and the total number of employees in the food industry was known over the same period of time. Incidence rates of OSD and relative risks of atopic skin diathesis (AD) and respiratory atopy (RA) were calculated. The overall incidence rate (I) of OSD (in 3 years per 10.000 employees) was 67 (95% CI 58;76) in these occupations. Bakers had a higher risk of OSD, with an incidence of 191 (95% CI 156;226) compared to confectioners with I = 84 (95% CI 55;113) and cooks I = 34 (95% CI 28;40). Incidence rates were sex- and age-related. Females developed OSD with an incidence rate of 74 (95% CI 64;84) compared to males with I = 58 (95% CI 48;70). OSD occurred mostly between the ages of 15 and 24 years. Irritant contact dermatitis (ICD) was the main type of OSD. 36% of the bakers had an occupationally relevant Type I allergy, while Type I allergies were less frequent in confectioners (16%) and cooks (9%). Assuming a prevalence of 10% of AD in the general population the relative risk (RR) of developing OSD in bakers, confectioners and cooks with AD was 9.7, 10.5 and 5.2, respectively. There were only small differences in calculating sex-related RR of AD.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Reduction of Nitrated Diphenylamine Derivatives under Anaerobic Conditions.

2-Nitrodiphenylamine, 4-nitrodiphenylamine, and 2,4-dinitrodiphenylamine were anaerobically metabolized in sediment-water batch enrichments inoculated with mud from the German North Sea coast. The first intermediate in 2,4-dinitrodiphenylamine degradation was 2-amino-4-nitrodiphenylamine, which appeared in large (nearly stoichiometric) amounts before being completely reduced to 2,4-diaminodiphenylamine. Of the second theoretically expected metabolite, 4-amino-2-nitrodiphenylamine, only traces were detected by gas chromatographic-mass spectrometric analysis in highly concentrated extracts. In addition, low levels of 4-nitrodiphenylamine, which may be the product of ortho deamination of intermediately produced 2-amino-4-nitrodiphenylamine, were observed. 2-Nitrodiphenylamine and 4-nitrodiphenylamine were primarily reduced to 2-aminodiphenylamine and 4-aminodiphenylamine, respectively. Diphenylamine was never detected in any experiment as a theoretically possible intermediate. Results from studies with dense cell suspensions of anaerobic, aromatic-compound-mineralizing bacteria confirmed the transformation reactions, which were carried out by microorganisms indigenous to the anaerobic coastal water sediment.

Journal Article↗
PubMed1995

Glomerular permselectivity in proteinuric patients after kidney transplantation.

To characterize the defect in glomerular permselectivity responsible for proteinuria after renal transplantation, we studied 10 patients with moderate proteinuria (median 0.37 g/d, range 0.20-0.79), 16 patients with the nephrotic syndrome (6.73 g/d, 3.9-14.6), 8 living related donor transplant recipients without any history of rejection (median proteinuria 0.26 g/d, 0.06-0.58), and 12 healthy volunteers. The fractional clearance of neutral dextrans > 54 A was significantly higher in nephrotic patients, demonstrating a defect in glomerular size selectivity. Using a log-normal model of glomerular pore size distribution, r*(5%) and r*(1%), indices for the presence of large pores, were increased in the nephrotic patients. The fractional clearance of negatively charged dextran sulfate was significantly higher in all patient groups, indicating a loss of glomerular charge selectivity. Biopsy findings showed more prominent glomerular lesions in the nephrotic group compared with the moderately proteinuric group. We conclude that mild proteinuria late after renal transplantation is associated with a defect in glomerular charge selectivity. The development of nephrotic range proteinuria is associated also with a defect of glomerular size selectivity, which correlates with prominent glomerular pathology.

Adult↗
PubMed1995

[The effect of valproic acid monotherapy on behavior and cognitive performance of children with idiopathic generalized epilepsy].

Valproic acid (VPA) currently plays an important role in the treatment of several different types of epilepsy. Especially in children and adolescents, VPA is used because of a minimum of adverse effects and generally little impact on cognitive and psychomotor functions. However, reports in the literature regarding the influence of VPA on behavior and cognitive performance and on EEG parameters vary widely. We investigated the effect of VPA monotherapy on behavioral components (attention, concentration, inhibitory control), cognitive efficiency (motor reaction time, learning, retention) and evoked potentials in 19 children aged 6 to 14 years with idiopathic generalized epilepsy and compared the results with those of healthy controls matched for age. In addition, we analyzed the serum levels of VPA and some of the VPA metabolites in all of the children with epilepsy immediately before the psychophysiological assessments. Our results show marked differences between the children with epilepsy and the healthy controls in all types of behavior and cognitive performance assessed. Abnormal behavior (disturbances of attention and concentration, impulsive behavior patterns) and significant changes in evoked potentials appear to be correlated with serum levels of VPA and certain VPA metabolites.

Adolescent↗
PubMed1995

Inhibition of smooth muscle cell proliferation and neointimal growth by low-anticoagulant heparin.

Low-anticoagulant heparin (LA-heparin) obtained by affinity chromatography on antithrombin III Sepharose inhibits the proliferation of cultured arterial smooth muscle cells in an in vitro bioassay system as effectively as standard heparin. A growth inhibition of smooth muscle cells of about 60% is achieved when LA-heparin or heparin is added to the culture medium to a concentration of 50 micrograms/ml. In normolipemic rats LA-heparin suppresses the formation of neointimal thickenings and stenosis after balloon catheter-induced deendothelialization of the carotid artery. In terms of mass a dose of 5 mg/kg body weight/d given subcutaneously twice daily one week before and 2 weeks after balloon injury the cross sectional area of the neointima is reduced to 36% as compared with the nontreated control group (100%). This 64% reduction is statistically highly significant (p < 0.001). After treatment with 0.5 mg LA-heparin/kg/d the reduction of the neointima was 11% (p < 0.05). At a dose of 5 mg/kg body weight single or repeated administrations of LA-heparin caused only a small and transient increase in activated partial thromboplastin time values. The results show that subcutaneous administration of LA-heparin very effectively prevents smooth muscle cell proliferation and balloon catheter-induced neointimal growth. The well tolerated systemic application of this chemically non-modified LA-heparin might justify clinical trials for prevention of restenosis after percutaneous transluminal coronary angioplasty or other invasive cardiovascular interventions without complications of bleeding.

Angioplasty, Balloon↗
PubMed1995

Growth status-dependent changes of bFGF compartmentalization and heparan sulfate structure in arterial smooth muscle cells.

Cultured bovine arterial smooth muscle cells express 6 to 7 ng basic fibroblast growth factor (bFGF)/mg cell protein and distribute it to two compartments. About 80% of total bFGF remain intracellularly, 20% are present in the pericellular (trypsin-releasable) compartment. No bFGF can be detected in the culture medium. All bFGF fractions have full biological activity. They are quantified by a highly specific immunoassay system and identified after sodium dodecyl sulfate polyacrylamide electrophoresis as a 18 kDa double band by immunoblotting. During exponential growth the intracellular concentration of bFGF decreases from about 130 pg to 20 to 40 pg/10(5) cells. Simultaneously the pericellular bFGF increases to 60-70% of total bFGF, but declines continuously with increasing cell density, whereas the intracellular bFGF reincreases under these conditions. The pericellular bFGF is known to form complexes with (membrane integrated) proteoheparan sulfate which undergoes structural changes during transition from subconfluent to confluent growth status. After metabolic labeling of the cells with [35S]sulfate and [3H]glucosamine, the 35S/3H ratio of heparan sulfate oligosaccharides increases from 1.58 during proliferation to 2.47 in growth-inhibited cells. The results indicate that the bFGF-induced proliferation of arterial smooth muscle cells depends on the pericellular localization of bFGF and on a specific molecular organization of the cell surface heparan sulfate. Depending on its specific structural characteristics heparan sulfate may promote or inhibit bFGF receptor binding and signal transduction.

Animals↗
PubMed1995

[Comparison of donor defects of fibula and iliac crest grafts].

In order to study the donor-site morbidity following osteocutaneous fibula and iliac-crest flaps, 17 patients were asked to answer a questionnaire and to present for a follow-up examination. The donor defect after fibula graft was preferred to the iliac crest donor defect with respect to esthetic appearance and complication rate.

Adult↗
PubMed1995

[Assessment of severity of mitral insufficiency--value of various color Doppler echocardiographic methods].

A total of 79 patients with mitral regurgitation (age 62 +/- 11 years, 45 men, 34 women) quantified by angiography was studied using color-Doppler imaging of isovelocity surface areas in the flow convergence region proximal to the regurgitant orifice (PISAs), of the jet cross-section at the level of the regurgitant orifice and of the regurgitant jet in the left atrium. The PISA-radii for the flow velocities (aliasing borders) of 28 and 41 cm/s, the cross-sectional jet area and the jet length, and relation of jet area to left atrial area were measured. The sensitivity for the detection of mitral regurgitation was at least 97% for the color-Doppler methods investigated in these patients in which a sufficient imaging was obtained. However, a sufficient imaging of the flow convergence region and the jet cross-section was not possible in about 5% of all patients. The PISA-radii for both flow velocities and the cross-sectional jet area correlated more closely with the angiographic grade (rSp = 0.79-0.80, p < 0.001) than the jet area (rSp = 0.39, p < 0.001), jet length (rSp = 0.37, p < 0.001), and relation of jet area to left atrial area (rSp = 0.31, p < 0.01) did. A correct differentiation of grades I to II from grades III to IV mitral regurgitation was provided in 93-95% of patients by the proximal flow convergence and by the cross-sectional jet area method and, at most, in 76% of the patients by the jet area method using the uncorrected jet area.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗