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Biomedical subjects

U Schmidt

Publications and source records attributed to U Schmidt.

At least 235 records · Page 13Linked to original sources
PubMed1993

[Malignant paragangliomas--the results of radiotherapy in 6 patients].

Between February 1984 and May 1989, six patients (four male, two female) with malignant paragangliomas of the carotid body (n = 4) and glomus jugulare (n = 2) were irradiated in the Department of Radiation Oncology at Essen University. All patients had macroscopic (residual) tumor at the start of treatment. Five out of six paragangliomas had to be considered malignant, since histological lymph node involvement or distant metastasis was confirmed. In the sixth case extra- and intracranial tumor growth was observed. Total doses between 40 and 55 Gy using cobalt 60, 10 or 15 MeV photons were administered. Radiation therapy was canceled at 30.6 Gy in one patient because of multiple distant metastasis. Three out of four patients, who received curative treatments, were locally controlled (25 to 91 months). A local recurrence in one patient was detected 18 months after irradiation; this patient died of distant metastasis 23 months after treatment. In one out of two palliatively irradiated patients, local control could be achieved until the patient died of distant metastasis twelve months after treatment. Grade III- or grade IV-treatment toxicity was not observed. Radiation therapy of malignant paragangliomas with doses between 45 and 54 Gy in five to six weeks is an effective treatment with low toxicity and should be preferred to surgery in glomus jugulare and advanced carotid body tumors.

Adult↗
PubMed1993

[Late pelvic recurrence of rectal cancer].

We report on a case of late pelvic recurrence of a rectal carcinoma 15 years after primary abdominoperineal resection and radiotherapy (primary stage T2 N0 M0; Dukes B). The origin of the recurrent tumour was undoubtfully proved by histological examination of the palliatively resected recurrent carcinoma.

Adenocarcinoma, Papillary↗
PubMed1993

The association of pulmonary CMV infection with interstitial pneumonia after bone marrow transplantation. Histopathological and immunohistochemical findings in 104 autopsies.

Lung tissue of 104 necropsies was studied by routine (HE) histology, by immunohistochemistry and partly by in situ hybridization in order to explore the association of pulmonary cytomegalovirus (CMV) infection and interstitial pneumonia (IP) after allogeneic bone marrow transplantation. IP was detected in 59 of 104 patients (56%). 12 of these (20% of the IP cases) presented as CMV-IP. No evidence of a CMV infection was obtained in the remaining 47 IP. Immunohistochemistry did not improve the CMV detection essentially over the results of routine (HE) analysis of viral inclusions. In situ hybridization performed on frozen sections of 21 cases turned out to be more sensitive than routine histology and immunohistochemistry, detecting active as well as latent CMV infections. However, the clinical relevance of latent infections, as disclosed by positive hybridization results in the absence of nuclear inclusions as well as immunohistochemical positivities, seems to be low, because latent infections typically were not found to be associated with IP.

Autopsy↗
PubMed1993

[Quality assurance in trauma surgery--what does the TRISS method offer ?].

The TRISS method offers a standard approach for evaluating the outcome of trauma care. Based on the data of more than 150,000 patients, TRISS offers a method of calculating the individual probability of survival of trauma patients. The calculation is based on anatomical, physiological data and the age of the patient. The basic scores for using TRISS are the Revised Trauma Score and the Injury Severity Score. Recent analyses demonstrate for blunt trauma patients a sensitivity of 60.9% and a specificity of 99.2%. What does TRISS offer in comparison to other trauma scores? TRISS offers a valid approach for the screening of trauma patients regarding unexpected survival/death. Based on the largest database of trauma patients, TRISS represents a method of maintaining quality assurance for prehospital and hospital trauma patient care; it also allows comparison with international standards of trauma care.

Adult↗
PubMed1993

[Primary management of polytrauma. Comparison of a German and American air rescue unit].

Hospital-based helicopter services from German and American university-affiliated trauma centers were reviewed. All multitrauma patients transported via helicopter from the scene of the accident to the trauma center during a 1-year period were included. The patients were comparable regarding mechanism of injury, age, flight times, mean ISS, ISS distribution, and number of severe injuries per body region (patients with AIS > 3 for head, thorax and abdomen). Overall mortality for the German system was 21/221 (9.5%) and 21/186 (11.3%) for the American system (not significant). Survivor-based TRISS analysis yielded Z-statistics of +2.459 for the German, and +1.049 for the American system. There were 9 unexpected survivors (Ps < 0.5) in the German, 6 in the American system. There was a significant higher (P < 0.01) number of early deaths (< 6 h) in the American population (12, ISS 56) than in the German (4, ISS 64). Analysis of the prehospital data demonstrated significant differences in the mean volume of IV fluids infused: 1800 cc German, 825 cc American (P < 0.05); rate of intubation: 82/221 (37.1%) German, 24/186 (13.4%) American (P < 0.001); and thoracic decompressions: 20/221 (9.1%) German, 1/186 (0.5%) American (P < 0.001). Pre-hospital care in the German system is directed on-scene by a trauma surgeon member of the flight crew, compared to a nurse/paramedic team with remote medical control in the American system. Compared to an American trauma system, the German system demonstrates improved overall outcome as measured by survivor-based TRISS Z-statistics. More favorable German Z-statistics are in part related to fewer early deaths.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

[Spatial confinement of intraocular picoseconds-photodisruption effects].

Laser photodisruption is a routinely performed clinical procedure in intraocular microsurgery of post-cataract membranes, anterior synechies and iridectomies. Damage ranges of several millimeters in diameter, however, limit the use of nanosecond photodisruption close to delicate structures, e.g., in the posterior vitreous. Multiple ps-laser pulses of about 100 microJ pulse energy were used to produce disruptive effects in the anterior lens capsule in rabbit eyes in vivo. Ophthalmoscopical and morphological investigations of these effects were compared with those of minimal ns-disruptions. The direct tissue separation effects as well as the collateral damage zones are about one order of magnitude smaller if ps-laser pulses are used. Minimal sizes of disruptive effects are about 50 microns to 150 microns and 500 microns to 1000 microns for ps- and ns-pulses, respectively. The substantial improvement of spatial confinement of ps-photodisruption enables increased precision of intraocular laser microsurgery and opens up new areas of clinical application in structures like the cornea, anterior chamber angle, and crystalline lens.

Animals↗
PubMed1993

Cardiac inotropic as well as coronary and pulmonary artery actions of epinine in human isolated tissues.

The present study was aimed to characterize the effects of epinine, the metabolite of the p.o. active dopamine derivate ibopamine in human cardiovascular tissues such as myocardium, coronary artery and pulmonary artery. Isometric force of contraction was studied in electrically driven papillary muscle strips from nonfailing (brain death), moderately failing (New York Heart Association class II-III, mitral valve replacement) and terminally failing human myocardium (New York Heart Association class IV, heart transplants) as well as in auricular trabeculae (aortocoronary bypass operation). Epinine increased force development in a concentration-dependent manner. In comparison to isoprenaline, epinine had a significantly lower potency but a similar efficacy to enhance force of contraction. Depending on the degree of myocardial failure, the effectiveness of epinine was reduced, whereas the potency was similar. Only in nonfailing myocardium, epinine increased force of contraction as effectively as Ca++. Prestimulation with forskolin or milrinone enhanced the potency of the epinine-mediated inotropic effect. In contrast, the beta-1-selective antagonist CGP 207.12A [2-hydroxy-5-(2-(hydroxy-3-(4-((1-methyl-4-trifluoromethyl)-1-H-imidazol -2-yl)-phenoxy)-propyl)-aminoethoxyl)-benzamide] and the beta-2-selective antagonist ICI 118.551 [erythro-(+-)-1-(7-methylindan-4-yloxy)-3- isopropylaminobutan-2-ol-hydrochloride] shifted the concentration-response curve of epinine significantly to the right, indicating action at both beta-2 and beta-1 adrenoceptors. Epinine exerted higher affinity at beta-2 compared to beta-1 adrenoceptors in radioligand binding experiments ([125I]iodocyanopinodolol). In human coronary artery rings and pulmonary artery rings epinine alone as well as epinine in the presence of propranolol initiated a concentration-dependent increase in tension development in precontracted (prostaglandin F2 alpha, 0.3 mumol/l) as well as in non-precontracted rings. These results suggest that epinine exerts no direct vasodilatory activity in human coronary and pulmonary arteries at concentrations which are capable to produce positive inotropic activity. The supposed beneficial effects of ibopamine in the treatment of heart failure may not be due to positive inotropic actions as the concentrations producing positive inotropy are much higher than the clinically observed plasma concentrations.

Adenylyl Cyclases↗
PubMed1992

Lipopeptides are effective stimulators of tyrosine phosphorylation in human myeloid cells.

Synthetic lipopeptide analogues of the N-terminus of bacterial lipoprotein are effective activators of macrophages, neutrophils and lymphocytes. We studied the effect of the lipopeptide N-palmitoyl-S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]- (R)-cysteinyl-(S)-seryl-(S)-lysyl-(S)-lysyl-(S)-lysyl-(S)-lysine [Pam3Cys-Ser-(Lys)4] on tyrosine phosphorylation in dibutyryl-cyclic-AMP-differentiated HL-60 cells, using anti-phosphotyrosine antibodies. Pam3Cys-Ser-(Lys)4 concentration-dependently stimulated tyrosine phosphorylation of 100/110 kDa and 60 kDa proteins and, to a lesser extent, of 55 kDa and 70/75 kDa proteins. Half-maximal and maximal effects were observed at concentrations of 1-6 and 5-50 micrograms/ml respectively. The lipopeptide-induced increase in phosphorylation was rapid and transient, with a peak response after 30-60 s. The lipopeptide (2S)-2-palmitoylamino-6-palmitoyloxymethyl-7-palmitoyloxy heptanoyl-Ser-(Lys)4 [Pam3Ahh-Ser-(Lys)4] was as potent as Pam3Cys-Ser(Lys)4, whereas (2S,6S)-2-palmitoylamino-6,7-bis(palmitoyloxy)heptanoyl++ +-Ser-(Lys)4 [Pam3Adh-Ser-(Lys)4] and Pam3Cys-Ser-Gly did not induce tyrosine phosphorylation. Lipopeptide-induced tyrosine phosphorylation was not affected by treatment of cells with pertussis toxin. Neither phorbol 12-myristate 13-acetate nor A23187 induced tyrosine phosphorylation in dibutyryl-cyclic-AMP-differentiated HL-60 cells. In HL-60 promyelocytes, Pam3Cys-Ser-(Lys)4 had no effect on tyrosine phosphorylation, whereas the lipopeptide also induced tyrosine phosphorylation in 1,25-dihydroxyvitamin-D3-differentiated HL-60 cells and in human neutrophils. These results show that lipopeptides are effective stimulators of tyrosine phosphorylation in mature human myeloid cells.

Blotting, Western↗
PubMed1992

Force-frequency relationship and inotropic stimulation in the nonfailing and failing human myocardium: implications for the medical treatment of heart failure.

In isolated papillary muscle strips from nonfailing donor hearts (NF) and from the hearts of patients with dilated cardiomyopathy with severe heart failure (NYHA IV), the force-frequency relationship was studied. Experiments were performed under basal conditions and in the presence of 0.01 microM or 0.1 microM isoprenaline and 0.02 microM ouabain. In NF, there was a positive inotropic effect following an increase of the stimulating frequency, whereas in NYHA IV, the force gradually declined under these conditions. Low concentrations (0.01 microM) of isoprenaline prevented the negative inotropic effect in NYHA IV, whereas at 0.1 microM the mechanical function deteriorated in NF and NYHA IV. Ouabain had no effect on the force-frequency relationship compared to basal conditions. It is concluded that a reduction of high frequencies does improve the contractility in the failing myocardium. It is not unreasonable to speculate that this mechanism might be involved in the beneficial effects of drugs which reduce the heart rate, such as beta-adrenoceptor antagonists and cardiac glycosides, in the condition of congestive heart failure in which the sympathetic tone is high.

Adult↗
PubMed1992

Self-splicing of a mitochondrial group I intron from the cytochrome b gene of the ascomycete Podospora anserina.

We have shown that the second intron of the Podospora mitochondrial gene coding for cytochrome b (Cytb 12) splices autocatalytically, using in vitro transcripts generated from the T7 promoter. The reaction takes place at 37 degrees C in the presence of 50 mM TRIS-HCl pH 7.5, 60 mM MgCl2 and 1 mM GTP but shows a low efficiency even at high KCl concentrations of up to 1.2 M. Under these conditions, intron bI2 follows the conventional pathway of group I splicing, and all characteristic products, with regard to both transesterification and hydrolysis, could be identified. Moreover, the intron is capable of undergoing cyclization, thereby releasing the noncoded G and one additional nucleotide (U) from the 5' end. The 5' cleavage site is preceded by the same two nucleotides, indicating a base-pairing at the same site of the internal guide sequence (IGS) for both splicing and cyclization ("one-binding-site model"). In addition, products resulting from site-specific hydrolysis 138 nucleotides downstream of the 5' splice site were detected. Unusually, the shortened intron is also able to form a circular RNA and an alternative sequence that aligns the cyclization site to the catalytic core of the intron must be assumed.

Ascomycota↗
PubMed1992

Modification by oxazepam of the diurnal variations in brain 125I-melatonin binding sites in sham-operated and pinealectomized rats.

Sham-operated and pinealectomized male rats were maintained at 14 h light:10 h dark cycles (lights-on 5.00 h) and injected daily, for 14 days, with oxazepam or vehicle. 125I-melatonin binding was recorded in synaptosomes prepared at 10.00, 18.00, and 24.00 h from the hypothalamus, hippocampus and medulla-pons of the rats. In the sham-operated, vehicle treated rats, specific 125I-melatonin binding in all brain areas studied was higher at 18.00 h, whereas in the oxazepam-treated animals, binding was higher at 24.00 h than at the other times tested. In the pinealectomized, vehicle-treated rats, the binding recorded at 18.00 h in all three brain areas, was lower than at the other times of day tested. Oxazepam treatment decreased 125I-melatonin binding at 24.00 h in the hippocampus and medulla-pons of the pinealectomized rats and did not significantly affect the binding in the hypothalamus. These results indicate the ability of oxazepam, pinealectomy and their combination, to manipulate the diurnal variations in 125I-melatonin binding sites in the rat brain.

Animals↗
PubMed1992

Mucoid cytoplasmic inclusions in urothelial carcinomas.

To date, mucoid cytoplasmic inclusions in urothelial carcinomas have rarely been noted. However, we were impressed by the fact that these corpuscles are readily detectable in numerous urothelial neoplasms. Therefore, a histologic analysis of 100 cases of urothelial carcinomas was performed. Overall, 37 cases revealed periodic acid-Schiff-positive cytoplasmic inclusions. These were observed in 14% of grade 1, 49% of grade 2, and 63% of grade 3 carcinomas. The inclusions were histochemically, immunohistochemically, and ultrastructurally identified as cytoplasmic deposits of mucoid materials. Two types of deposits, condensed and noncondensed, could be distinguished. The demonstration of mucoid deposits in otherwise poorly differentiated metastatic carcinomas may be of some differential diagnostic importance insofar as urothelial carcinoma has to be considered as the possible primary tumor.

Carcinoma, Transitional Cell↗
PubMed1992

Toxicity of 2,3,7,8-tetrabromodibenzo-p-dioxin in rats after single oral administration.

Five male and female rats per dose-group received 2,3,7,8-tetrabromodibenzo-p-dioxin (2,3,7,8-TBDD) once on the first day of the study. Doses of 10, 33, 100, or 300 micrograms 2,3,7,8-TBDD/kg body wt. and the vehicle control were administered by gavage. About 20% of 2,3,7,8-TBDD was excreted via feces. Severe body weight retardation was observed in the 100 and 300 micrograms/kg dose-groups. Most animals in the 300 micrograms/kg dose-group and the females receiving 100 micrograms/kg showed emaciation, rough coat and a poor health (wasting syndrome). Of the animals dosed with 300 micrograms/kg, 3 males and all females died. After 100 micrograms 2,3,7,8-TBDD/kg 3 females died. Measured 4 weeks after dosing, triiodothyronine (T3) was increased and thyroxin (T4) was reduced dose dependently in serum. A dose-dependent decrease in thymus weights was observed at necropsy and histological examinations showed that thymus and spleen were depleted of mature lymphocytes. An increase in liver-to-body weight ratio was observed in all dose-groups. The histological examination revealed hypertrophy of centrilobular hepatocytes in the liver of animals treated with 100 micrograms/kg, which was less severe at the 33 micrograms/kg dose. Hypertrophic hepatocytes were also detected in some animals at the lowest dose. Induction of enzyme activities of the mixed function oxidases ethoxycoumarin O-deethylase (ECOD), ethoxyresorufin O-deethylase (EROD) and aryl hydrocarbon hydroxylase (AHH) in liver tissue differed for each of the three enzymes. Two days after administration, enzyme activities were increased but did not differ substantially between dose-groups. Twenty-eight days after dosing the increase in activity after 10 micrograms/kg was largest and the EROD of the 100 micrograms/kg dose-group in females was close to that of the control. This inverse dose-response relationship may be due to impaired liver cell function at higher doses.

Administration, Oral↗
PubMed1992

Using Kryofix as alternative for formalin results in more optimal and standardized immunostaining of paraffin sections.

Although used for over one century formalin has several disadvantages which Kryofix, an alternative fixative for paraffin blocks used in Leiden for 6 years, does not have. In this study the effects of Kryofix on tissue regarding immunohistochemistry are compared with those of buffered formalin. All markers studied showed enhanced staining in the Kryofix blocks after 4 hours of fixation, whilst in some cases the immunostaining of the formalin blocks was even negative. For all markers, the sera could be further diluted for the Kryofix sections, for some with as much as a factor 20, enhancing the cost-effectiveness of the method. We established that for formalin, the fixation time strongly influenced the results. For Kryofix there was no time factor: the immunostaining results of 1 hour fixation were identical to those after 3 months of fixation. This study shows that by this method of fixation, in which there is no cross-linking of proteins, immunostaining of paraffin sections is optimized and standardized.

Ethanol↗
PubMed1992

Early onset bulimia nervosa: who is at risk? A retrospective case-control study.

The aim of the study was to compare the clinical features and predisposing characteristics of patients with an early onset of bulimia nervosa with those with a more typical onset. Twenty-three cases of early onset bulimia nervosa (onset age 15 or below) were compared with 23 sex- and class-matched cases of typical onset (onset age 17 to 21) using a retrospective case-control design. No difference was found in eating symptomatology between the two groups. Deliberate self-harm was more frequent in the early onset group, and there was a trend towards more depression among their relatives. Inadequate parental control occurred more often in the early onset group, but other indicators of intrafamilial disturbance did not differ in the two groups. There was also a trend for the early onset group to be exposed to more cultural stress as a result of family migration. Early onset patients were found to have a higher loading on risk factors than typical onset patients.

Adolescent↗