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Biomedical subjects

U Fiedler

Publications and source records attributed to U Fiedler.

At least 37 records · Page 2Linked to original sources
PubMed1995

Mechanism of activation of a response regulator: interaction of NtrC-P dimers induces ATPase activity.

NtrC is the transcriptional activator for nitrogen-regulated promoters and, as a response regulator, belongs to the protein family of two-component systems. The activity of all response regulators is modulated by phosphorylation of the conserved N-terminal receiver domain. Phosphorylation of the dimeric NtrC has two consequences: (i) a strong increase in the cooperative binding of NtrC to two adjacent binding sites and (ii) activation of NtrC as an ATPase. Here we show that phosphorylation of NtrC is not sufficient for activation of NtrC. At low protein concentrations (50 nM), phosphorylated NtrC was only active as an ATPase upon cooperative binding to DNA. At high protein concentrations (above 50 nM), NtrC was active in the absence of DNA, and activation occurred in parallel with the formation of high-molecular-weight aggregates. We infer that activation of NtrC involves an interaction between two NtrC-P dimers and proceeds in two steps. The first step is the phosphorylation of NtrC. The second step is the interaction between two NtrC-P dimers. This interaction induces the conformational change in NtrC-P to the active conformation.

Adenosine Triphosphatases↗
PubMed1994

Ileal conduit urinary diversion 16 months before renal transplantation in a case of non-functioning lower urinary tract.

The case history of a cadaveric kidney graft recipient with complete non-functioning of the lower urinary tract is reported. An ileal conduit was formed 16 months prior to transplantation. The graft ureter was implanted into the conduit without any problems, graft functioning was excellent, and no surgical, metabolic, or infectious complications occurred during the 18-month follow-up period.

Adult↗
PubMed1993

A complex ensemble of cis-regulatory elements controls the expression of a Vicia faba non-storage seed protein gene.

We have identified cis-regulatory elements within the 5'-upstream region of a Vicia faba non-storage seed protein gene, called usp, by studying the expression of usp-promoter deletion fragments fused to reporter genes in transgenic tobacco seeds. 0.4 kb of usp upstream sequence contain at least six, but probably more, distinct cis-regulatory elements which are responsible for seemingly all quantitative, spatial and temporal aspects of expression. Expression-increasing and -decreasing elements are interspersed and include an AT-rich sequence, a G-box element and a CATGCATG motif. The latter acts as a negative element in contrast to what has been found for the same motif in legumin- and vicilin-type seed storage protein gene promoters. Seed specificity of expression is mainly determined by the -68/+51 region which confers, however, only very low levels of expression. The data support the combinatorial model of promoter function.

Base Sequence↗
PubMed1993

Automated histomorphometry of interstitial reactions in the heart.

A method is presented suitable to measure changes in area densities of the total Sirius red-stained interstitial tissue in longitudinal sections of rat hearts by means of computer-aided image analysis considering at the same time the behavior of six regions and changes in the percentage of thick connective tissue fibers in the total interstitial tissue. Verification tests were directed to the influences of preparation, adjustment of the grey-level thresholds, and identification of the various regions, to marginal conditions of measurement and the investigators. The reliability of the method with acceptable total errors is demonstrated.

Animals↗
PubMed1993

Hygroma renale: pararenal lymphatic cysts associated with renin-dependent hypertension (Page kidney). Case report on bilateral cysts and successful therapy by marsupialization.

A total of 42 cases of large symptomatic parapelvic or pararenal lymphatic cysts has been reported since 1890, of which 54% were associated with hypertension and 14% were bilateral. We report on a patient in whom during a 3-month period abdominal pain and distention developed successively on both sides associated with hypertension. Initially, ultrasound and computerized tomography revealed a large multicystic pararenal lymphatic mass on the right side and small parapelvic hilus lesions on the left side. Two months after resection and marsupialization of the large cyst on the right side the small hilus lesions on the left side developed into large pararenal cysts requiring the same therapeutic measures. Hypertension was reversible after surgery in both instances; at the second operation high preoperative and lower postoperative renin activity, active renin, total renin, aldosterone and atrial natriuretic factor in plasma were noted. Immunoreactive active and total renin levels in the lymph fluid were elevated, a finding that may be explained by the renal origin of the lymph. Marsupialization is a kidney preserving measure that reverses all symptoms of large pararenal cysts, including Page kidney hypertension.

Adult↗
PubMed1988

Transplantation of a horseshoe kidney en bloc: report of a case.

Transplantation of a horseshoe kidney rarely has been reported. We report a case of successful en bloc transplantation of a horseshoe kidney. The kidney could not be divided because of a complex vascular situation in the isthmus region. The recipient was discharged from our hospital with normal kidney function 12 days postoperatively. We recommend the use of kidneys with anatomical malformations for transplantation.

Adult↗
PubMed1988

[Perineal ectopic testis].

The case of a 24-year-old patient is presented who was erroneously presumed to have unilateral testicular aplasia following inguinal exploration in early childhood. At the age of 24 years he underwent surgery for a soft perineal mass, which was found to be perineal testicular ectopia associated with a congenital hernia. Histological examination of the excised testicle revealed atrophy of the germinal epithelium. A survey of the literature yielded approximately 175 more cases of perineal testicular ectopia. This is the most frequent from of testicular ectopia with a relative incidence of less than 1% of all cases of undescended testes. Ectopic testes seem only to differ from undescended testes in terms of topography. Little difference can be observed in terms of histology or the incidence of concomitant hernias.

Adult↗
PubMed1986

[DTIC: effect on fibrinolysis and thrombocyte function].

Pathogenesis of Budd-Chiari-syndrome, under treatment e.g. of malignant melanoma with DTIC (dacarbacin) is still unknown. In our investigations we could not find any hint for the hypothesis that Budd-Chiari-syndrome under DTIC is caused by hemostaseological impairment.

Blood Coagulation Tests↗
PubMed1983

Effects of angiotensin II and ACTH on normal and tumourous human adrenocortical cells.

Isolated adrenocortical cells from 6 patients with a 'normal' zona fasciculata, 4 patients with a 'normal' zona glomerulosa, and tumour cells from 1 adrenocortical adenoma and 1 carcinoma were incubated with and without increasing concentrations of ACTH 1-24 (10(-13) M to 10(-9) M) or Asp1-Ile5-angiotensin II (10(-11) M to 10(-7) M). In 4/5 'normal' cases, cortisol was clearly stimulated by 10(-13) M ACTH. The maximum of the dose-response curve (5-fold stimulation) was reached at 10(-10) M ACTH. Angiotensin II (AII) started to stimulate 'normal' cells at 10(-11) M with a maximum (2-fold stimulation) at 10(-9) M. Aldosterone production by 'normal' cells was less markedly stimulated by ACTH and AII, although the threshold doses for both peptides were similar to those of the cortisol response curves. The cells of the adrenocortical adenoma from a patient with Cushing's syndrome produced large amounts of cortisol and small amounts of aldosterone, both steroids being clearly stimulated by ACTH and AII. The adrenocortical carcinoma cells produced small amounts of cortisol and no aldosterone. Cortisol production responded to ACTH, but not to AII. The results suggest that an activated renin-angiotensin system may stimulate the zona fasciculata, since 10(-11) M AII (= 10 pg AII/ml) is a normal plasma AII concentration on an unrestricted diet. Clinical evidence supporting this thesis is reviewed. However, cortisol production itself will rarely be increased by AII in vivo, since a down-regulation of ACTH would occur.

Adenoma↗
PubMed1982

[Long-term results after kidney transplantation].

In this investigation, our own long-term results after kidney transplantation were compared with those in literature, and the influence of recent findings on the survival rate of patients and transplants was analyzed. In 217 kidney transplant patients, the 5 and 9-year-patient survival rate was calculated at 58% and 45% respectively. The 9-year-transplant function rate was 38%. Analogous results can be derived from collective international and European statistics. The long-term patient survival rate after successful transplantation shows better results than comparable statistics of hemodialysis treatment. Analysis of the results fractionated into the years 1970 to 1974, 1975 to 1977 and 1978 to 1981 shows a continuous improvement in the survival rate of patients and transplants. This improvement of results can be attributed to the reduction of surgical complications with increasing experience and particularly to knowledge recently gained in the field of transplantation immunology (compatibility in the HLA-A/B and -DR system, preoperative blood transfusions) and immunosuppression (reduction of steroid doses, supplementary ATG and cyclosporin A medication).

Adult↗
PubMed1981

Determination of auto-antibodies against spermatozoa in experimental cryptorchism.

In 70% of the patients with unilateral retentio testis the normal descended testicle shows damage in spermiogenesis too. The formation of auto-antibodies is considered as a possible cause. In rats with artificial uni- and bilateral cryptorchism, this mechanism was examined. The presence of auto-antibodies against spermatozoa could be proven by indirect immunofluorescence. After uni- and bilateral intra-abdominal displacement of the testicles, this phenomenon takes place after the 3rd month post-operatively, shows the maximum of titers after 6 months and decreases towards the 9th month post-operatively. An animal model is presented, suitable for the study of immunological processes in unilateral gonadal diseases.

Animals↗
PubMed1981

[Value of computer tomography in the staging of bladder and prostatic cancer].

In carcinomas of the urinary bladder we regard a humpy contour of the outer wall of the bladder as a transmural growth of the tumour, i.e. stage T4. A retraction of the wall or a plateau phenomenon was assigned to an intramural infiltration (stage T2 or T3). Contrary to the caudal lymphography in several cases changes in the nodes of the iliaca interna-group could be proved. The computer tomography seems to prove in such cases, in which the arteriography of the urinary bladder could not fulfil the expectations (9, 10). The results illustrate that by means of the methods chosen by us a delimitation of early invasive form paravesically growing vesical tumours is possible (12, 17, 18). In the classification of the carcinoma of the prostate the computer tomography does not give more essential informations in comparison to the rectal palpation, the vesiculography and the lymphography. The distinction of a normal prostate from the benign or malignant tumour tissue is not successful, since there are no specific differences in density. Particularly the tumour infiltration into the seminal vesicles could not be established early enough (7, 13). In the estimation of regional settlements of lymphatic nodes the statements are above all based on controls of the course, only a few cases could be ascertained histologically. In these cases it is necessary to keep in mind that in the computer tomography only lymphatic nodes from a diameter of 1.5-2 cm are recognizable. Since the computer tomography is a non-invasive method, it can be used for the pre- and postoperative diagnostics as well for controls of the course in tumour diseases of the lower urinary tract (2, 8, 20). However, no evidence can be made on the dignity of the spacial demands.

Aged↗
PubMed1979

Comparative analysis of the results of suspension-urethroplasty according to Marshall-Marchetti-Krantz and of urethrovesicopexy with adhesive.

A comparative analysis is presented of the results of adhesive urethrovesicopexy and the conventional suspension method according to Marshall, Marchetti and Krantz. It appears that the results are less favorable when compared to those mentioned in the literature, and no doubt attributable to the difficult differential diagnosis of stress and urge incontinence. The adhesive method supplies significantly less favorable results than the conventional method according to Marshall, Marchetti and Krantz.

Adult↗
PubMed1979

[Determination of auto-antibodies against spermatozoa after vasectomy and epididymectomy by indirect immunofluorescence (author's transl)].

As a result of successful recanalization of the vas deferens, a low pregnancy rate has been observed. The formation of auto-antibodies is considered as cause. In vasectomized and epididymectomized rats, the presence of auto-antibodies against spermatozoa was proven by indirect immunofluorescence. After uni- and/or bilateral obstruction of the vasa, the formation of antibodies against spermatozoa takes place which - after 2 months - proves to be permanent for 9 months, then showing a decreased titre. An animal model is presented suitable for the study of immunological processes in unilateral gonadal diseases.

Animals↗
PubMed1979

[Indications, technique and results in treatment of hypospadias (author's transl)].

Surgical indications and results are reported in a 66 patients. The very suitable methods for distal hypospadias repair according to Hoffmann-Hall and Dettmar with their advantages are presented as a supplement to the genial method of Meyer-Burgdorff and Denis Browne. A schematic procedure is described for choosing the preferred method od operation, as illustrated by our good results.

Child↗
PubMed1979

[Comparative statistic of complications in openprostatectomy and transurethral resection (author's transl)].

On the basis of the case material of 1049 patients, the advantages and disadvantages of enucleation and the transurethral resection of the prostatic adenoma are compared. There are no significant differences in the lethality of the operation. Although at present preference is generally given to the transurethral resection, this procedure appears less favorable to us with regard to the intraoperative complications as well as late complications of urethral strictures, during long-term follow-up.

Adult↗