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Biomedical subjects

U Weber

Publications and source records attributed to U Weber.

At least 91 records · Page 5Linked to original sources
PubMed1998

[Tumor-related arthrodesis. Reconstruction of the shoulder contour using a free TRAM (Transverse Rectus Abdominis Musculocutaneous) flap].

Upper arm bone- and shoulder resection due to cancer have to be performed under oncologic criteria. Soft tissue however may not be sufficient to safely cover a following arthrodeses. To avoid perforation and reconstruct a normal shoulder contour a free myocutaneous TRAM-flap was employed and its vessels anastomosed to branches of A. and V. brachialis. Incorporating the facia and an island of M. rectus abdominis proved to safely cover the arthrodetic material and shape the bulk of the flap, allowing to reconstruct the desired contour. Good vascularisation postoperatively preserved tissue stability and volume and thus safely restored normal shoulder contour even in a long time review.

Abdominal Muscles↗
PubMed1998

[Microsurgical transoral decompression in diseases of and injuries to the cranio-cervical junction].

Besides the microsurgical ventral decompression for treatment of cervical disc prolapses, combined with an intercorporal fusion using an autologous bone graft from the iliac crest and a plate osteosynthesis, the microsurgical, transoral approach to the craniocervical junction has proven to be an effective procedure for adequate indications. Even for surgical treatment of diseases and injuries of the craniocervical junction ventral, anterolateral, lateral and dorsal approaches are applicable alone or in combination. The special anatomic and functional conditions of this region, however, obviously require that the indicational criteria for the various approaches differ from those selected for the other cervical segments. The postoperative complication risk requires that particulary critical consideration be given to the question of isolated transoral interventions. The same holds true for the question as the necessity for additional ventral stabilisation in combined dorsoventral interventions. This report is about 20 patients who underwent transoral decompression, about the indications and the procedure typical problems.

Bone Neoplasms↗
PubMed1998

[Femur head preserving therapy, using vascular pedicled iliac bone graft, in segmental femoral head necrosis].

Various therapeutic options have been proposed in the treatment of femoral head necrosis ranging from conservative management to total hip arthroplasty. Since microsurgical techniques are routinely used in orthopaedic surgery, the importance of revascularization has increased in recent years. Vascularized bone grafting as well as various osteotomies have been considered for the stages II and III according to Ficat and II, III and IV of the criteria of the ARCO system respectively, which also bases on MRI-findings. We investigated the results of 80 patients with avascular necrosis of the femoral head treated with a vascular pedicled iliac bone graft, perfused by the A. circumflexa ilium profunda, between 1988 and 1996. Mean follow-up was 5.6 years. The evaluation was based on the harris hip score, clinical and radiological examination as well as a subjective assessment using a VAS (visual analog scale). The clinical results according to the harris hip score were good or excellent in 86.1%. These results correlate with the subjective assessment of pain and of the hip joint function with an average of 7.9 points using the VAS (max. 10 points). Unchanged radiological appearance over the follow-up period was observed in 47.5% using the ARCO criterias. Reviewing the studies using vascularized grafts, about 50% of the patients with a stage II and III according to Ficat and II, III and IV of the ARCO respectively show an unchanged stage of the disease 5-6 years after the procedure. Therefore, transplantation of a vascular pedicled iliac bone graft possibly offers the chance to intervene causally in the course of the disease with only little alteration of the biomechanics of the hip joint.

Arthroplasty, Replacement, Hip↗
PubMed1998

Health impact associated with vertebral deformities: results from the European Vertebral Osteoporosis Study (EVOS).

To study the association between vertebral deformities and subjective health outcome indicators, including back pain and disability, a cross-sectional survey with spinal radiographs and personal interviews was carried out in 36 study centres in 19 European countries on a total of 15,570 men and women aged 50-79 years (population-based stratified random samples). No interventions were done. The main outcome measures were the presence and intensity of current and previous back pain, functional capacity (ADL questionnaire) and overall subjective health. The presence and intensity of back pain and functional and health impairments varied within wide ranges with no obvious regional pattern. However, the associations between negative health outcomes and vertebral deformity were homogeneous between countries and between centres within countries. In logistic regression analyses weak but significant associations between the presence of vertebral deformities and various health indicators were demonstrated. The magnitude of the associations increased with severity and number of deformities. Compared with subjects without deformities those with low-grade deformities had no or only a weakly elevated risk for back pain, disability and impaired subjective health (odds ratios (OR) 1.2-1.3). The odds ratios increased for individuals with single severe deformities (OR 1.3-2.1) and were highest in those with multiple severe deformities (OR 1.7-4.2). The associations between vertebral deformities and negative health outcomes were stronger in men than in women. In this cross-sectional study radiologically assessed vertebral deformities were therefore weakly associated with both current and previous back pain as well as with functional and health impairments in both women and men. Multiple severe deformities were associated with severe and disabling back pain with stronger effects in men.

Activities of Daily Living↗
PubMed1998

[Cataract operation after silicone oil surgery. Oil drop adhesion to silicone lenses].

PURPOSE: To investigate the phenomenon of oil droplet formation on silicone IOLs with regard to visual acuity, intraocular pressure (i.o.p.), and clinical findings. PATIENTS AND METHODS: Retrospective study (january 1995 to December 1996) on 78 patients who underwent cataract surgery after previous complex silicone oil surgery for PVR-complicated rhegmatogenous retinal detachments (64) or proliferative diabetic retinopathy (14). Follow-up after cataract surgery 15.5 (7.55) months. PMMA IOLs were used in 50 and silicone IOLs in 19 cases. Nine patients did not receive an intraocular lens. The groups were divided up further with regard to secondary YAG capsulotomies and oil explanations. Before cataract operation, one or two (1, 23) complex vitreoretinal operations were performed with case-dependent additional retinal laser coagulations. For statistical analysis the two-sided t-test and/or Welch's test were applied. RESULTS: The preoperative mean visual acuity (VA) was significantly better (P < 0.0001) in the group treated with PMMA IOLs than in the one without IOL (VA with PMMA 0.093, silicion 0.075, without IOL 0.026). Significant improvement of VA after surgery was found with PMMA Implantation after YAG capsulotomy without silicone oil explantation (P = 0.0003). Visual improvement was best in PMMA IOLs after YAG capsulotomy with the remaining silicone oil (0.076), followed by the group without IOL implantation (0.063). In the groups with PMMA IOLs/YAG/oil explantation, a rise in VA of 0.06 was achieved, and in silicone IOLs/YAG/oil explantation, the rise in VA was 0.002. No statistically significant differences were found in postoperative mean VA. Preoperative intraocular pressure (i.o.p.) was lower in the PMMA group than in the group without IOL (P = 0.0447). No significant differences in the postoperative IOPs were found between groups, but in the PMMA/YAG/oil in situ group, IOP decreased significantly after surgery (P = 0.0142). Maculopathies were found in the PMMA group in 31, in the silicone group in 16, and in the group without IOL implantation in 7 cases. Optic atrophy was found in the PMMA group in 8, in the silicone group in 4, and in the group without IOL implantation in 3 cases. CONCLUSIONS: In all groups silicone oil surgery and secondary cataract operation with or without YAG capsulotomy and oil explantation achieved stable or slightly improved mean VA with significance in PMMA IOL implantation/YAG capsulotomy without oil explantation. Comparing PMMA IOLs/YAG/oil explantation and silicone/YAG/oil explantation, an advantage in the PMMA groups was found. However, because of large interindividual differences (large standard deviations) there was no statistical significance. Thus, in this series the phenomenon of silicone droplet adhesion on silicone IOLs is secondary to the influence of retinal pathologies.

Adult↗
PubMed1998

[Effect of drug-induced vasodilatation of basal brain arteries with nitroglycerin on blood flow velocity and volume flow in the middle cerebral artery].

AIM: The Müller-Casty flow index (FI) is recommended for use in transcranial Doppler sonography (TCD) to measure relative changes in volume flow. We examined the ability of the FI to assess the volume flow during diameter changes of basal cerebral arteries. METHOD: Nitroglycerin (NTG) was used to induce dilation of basal cerebral arteries without affecting cerebral blood flow. Transverse and sagittal sections of the middle cerebral artery (MCA) were obtained by magnetic resonance imaging (MRI) and blood flow velocities in the MCA were measured by TCD. The FI was calculated by multiplying Doppler shift frequency and signal power. RESULTS: NTG induced an increase of MCA-diameter in MRI. The mean FI remained approximately constant (-2.6 +/- 6%), while the mean blood flow velocity dropped significantly (-15 +/- 6%). CONCLUSION: The FI can be used to estimate volume flow in basal cerebral arteries even in case of diameter change.

Administration, Sublingual↗
PubMed1998

Ultrasonographic comparison of adhesions induced by two different methods of gastropexy in the dog.

Ultrasonography was used to compare adhesions induced by two different methods of gastropexy in 16 dogs. An incisional gastropexy technique was used in eight dogs (group 1) and a 'modified' gastropexy technique in the remaining eight (group 2). The length and thickness of the gastropexy and the peristaltic activity of the stomach were measured ultrasonographically and compared between groups. Measurements for the two groups were taken in the early postoperative interval (two to four days), intermediate postoperative interval (eight to 20 days) and late postoperative interval (57 to 79 days). Both techniques were equally successful in forming permanent adhesions at two months postoperatively and there was no recurrence of gastric dilatation and volvulus. The length and thickness of the gastropexy were similar for both groups at two months postoperatively and there were no surgical complications with either technique. The modified gastropexy provides a technique that can easily be performed by a single surgeon, with no increased operative time or duration of anaesthesia, and with the formation of a permanent adhesion.

Animals↗
PubMed1998

Syringe exchange in Germany.

Syringe exchange in Germany is clearly linked to a recent shift of local responses to drug-use(r) associated problem. Since the end of the 1980s, metropolitan communities in Northern and Central Germany-concerned by the emergence of "Open Drug Scenes," increasing HIV and mortality rates among drug users, and drug-use-related property crime-began to favor measures of survival-oriented drug-user help. While the Federal Government still favors repression and law enforcement efforts, they nevertheless made syringe exchange explicitly legal in 1992-some 5 years after the creation of local Syringe Exchange Programs. In general, the new approach of local authorities includes a variety of services, such as housing facilities, crisis intervention centers, primary medical care, maintenance with substitute drugs, and syringe exchange programs. The creation of pilot heroin maintenance programs is planned for Frankfurt and Hamburg. While the established programs are successfully functioning in large cities such as Hamburg, Bremen, and Frankfurt, the demand for sterile needles and syringes remains unmet in smaller cities and in the conservative governed Bundeslander (states), where pharmacies remain the primary and often single legal supply source for syringes. Another major problem continues to be the drug-use situation in prisons. Although injection drug use is common in prisons, injection equipment is not legally available for the 10,000 injecting drug users imprisoned at any given time. Two of Germany's 220 prisons started an experimental syringe exchange in 1996.

Drug and Narcotic Control↗
PubMed1997

[Therapeutic plasma exchange 1996].

Therapeutic plasma exchange (TPE) is an extracorporeal blood purification technique to remove large molecular weight substances. Since the late seventies TPE was used in a variety of diseases in which humoral factors may play a part in the pathogenesis. Today, accepted indications only exist for a few entities in defined situations: Anti-glomerular basement membrane antibody mediated disease, TTP/HUS, Guillain-Barré-syndrome, hyperviscosity syndrome, chronic polyneuropathy associated with IgG and IgA gammopathy, chronic inflammatory demyelinating polyneuropathy and myasthenia gravis.

Autoantibodies↗
PubMed1997

The role of RhoA in tissue polarity and Frizzled signalling.

The tissue polarity genes of Drosophila are required for correct establishment of planar polarity in epidermal structures, which in the eye is shown in the mirror-image symmetric arrangement of ommatidia relative to the dorsoventral midline. Mutations in the genes frizzled (fz), dishevelled (dsh) and prickle-spiny-legs (pk-sple) result in the loss of this mirror-image symmetry. fz encodes a serpentine receptor-like transmembrane protein required for reception and transmission of a polarity signal. Little else is known of the signalling pathway(s) involved other than that Dsh acts downstream of Fz. We have identified mutations in the Drosophila homologue of RhoA p21 GTPase, and by analysis of their phenotype show that RhoA is required for the generation of tissue polarity. Genetic interactions indicate a role for RhoA in signalling mediated by Fz and Dsh, and furthermore suggest that JNK/SAPK-like kinases are involved. These data are consistent with a Fz/RhoA signalling cascade analogous to the yeast pheromone signalling pathway and that proposed for activation of the serum response factor (SRF) in vertebrate cells.

Adaptor Proteins, Signal Transducing↗
PubMed1997

Comparison of loads on internal spinal fixation devices measured in vitro and in vivo.

The loads on internal spinal fixation devices were measured using modified, telemeterized AO-Dick internal fixators. The implants allow measurement of the three force components and the three moments acting on the implant. The modified fixators were mounted on cadaver spines, and the implant loads were measured in the intact and postcorpectomy spines for different loading modes, including axial compression force, flexion, extension, lateral bending, and torsion. The in vitro experiment did not consider muscle forces. Modified fixators were also implanted in three patients, and the implant loads were determined before and after anterior interbody fusion with autologous iliac-crest bone grafts. The results for different in vitro loading modes were compared with those in vivo in order to demonstrate the extent to which the in vitro loads represent the real situation in patients. In several cases, the implant loads in the in vitro experiment differed strongly from those measured in patients. For flexion and lateral bending, a tensile axial force occasionally was measured in the in vitro experiment, while in the patients the axial force was always compressive. Extension was predominantly associated with extension bending moments in the in vitro study but with flexion bending moments in the patients. When muscle forces are not considered in the in vitro experiment, the loads on the fixators may differ significantly from the situation found in patients.

Adult↗
PubMed1997

Genetic analysis of the catalytic domain of the chemotaxis-associated histidine kinase CheA.

Escherichia coli cells express two forms of CheA, the histidine kinase associated with chemotaxis. The long form, CheA(L), plays a critical role in chemotactic signal transduction by phosphorylating two chemotaxis-associated response regulators, CheY and CheB. CheA(L) first autophosphorylates amino acid His-48 before its phosphoryl group is transferred to these response regulators. The short form, CheA(S), lacks the amino-terminal 97 amino acids of CheA(L) and therefore does not possess the site of phosphorylation. The centrally located transmitter domain of both forms of CheA contains four regions, called N, G1, F, and G2, highly conserved among histidine kinases of the family of two-component signal transduction systems. On the basis of sequence similarity to highly conserved regions of certain eukaryotic kinases, the G1 and G2 regions are purported to be involved in the binding and hydrolysis of ATP. We report here that alleles mutated in the G1, G2, or F region synthesize CheA variants that cannot autophosphorylate in vitro and which cannot support chemotaxis in vivo. We also show that in vitro, the nonphosphorylatable CheA(S) protein mediates transphosphorylation of a CheA(L) variant defective in both G1 and G2. In contrast, CheA(L) variants defective for either G1 or G2 mediate transphosphorylation of each other poorly, if at all. These results are consistent with a mechanism by which the G1 and G2 regions of one protomer of a CheA dimer form a unit that mediates transphosphorylation of the other protomer within that dimer.

Alleles↗
PubMed1997

Activated clotting time is not a sensitive parameter to monitor anticoagulation with low molecular weight heparin in hemodialysis.

To study whether the activated clotting time (ACT) is a sensitive parameter to monitor anticoagulation with low molecular weight heparin (LMWH) during hemodialysis, ACT, polymorphonuclear granulocyte-elastase, and anti-factor Xa activity were studied during 30 dialysis treatments with LMWH (35 IU/kg body weight bolus; 10 IU/h/kg). Twenty treatments were performed with Hemophan, ten with polysulfone dialyzers. No clinically relevant clotting of dialyzers was observed, but minimal fibrin deposition was found more often in the Hemophan group (50 vs. 30%). Despite continuously elevated anti-factor Xa levels (Hemophan 0.49 +/- 0.03, polysulfone 0.62 +/- 0.01 IU/ml), a significant increase of ACT was only demonstrated 10 min after bolus application in the Hemophan group. Elevated polymorphonuclear granulocyte-elastase levels were demonstrated in the Hemophan group but were linked to the presence of minimal fibrin deposits and not to the dialyzer material. We conclude that ACT is not a sensitive parameter to monitor anticoagulation with standard doses of LMWH.

Anticoagulants↗
PubMed1997

Slow gastric emptying in type I diabetes: relation to autonomic and peripheral neuropathy, blood glucose, and glycemic control.

OBJECTIVE: To investigate whether autonomic neuropathy or hyperglycemia plays a crucial etiological role in gastric retention of ingesta frequently found in type I diabetic patients. RESEARCH DESIGN AND METHODS: We investigated the gastric emptying of a radiolabeled semisolid 1,168 kJ meal in 38 female and 45 male patients (age 18-75 years; illness duration 3-46 years). None took drugs affecting gastrointestinal motility. Fasted patients underwent tests of cardiovascular autonomic and peripheral nerve function. Blood glucose levels were determined before and after the scintigraphic recording of gastric emptying. RESULTS: The percentage of meal remaining in the stomach at the end of the 50-min recording time was related significantly to the patients' degree of cardiovascular autonomic neuropathy [r (81) = 0.235, P < 0.028] but not to their degree of peripheral neuropathy, preprandial blood glucose level, HbA1c indicative of glycemic control, diabetes duration, and age. The patients' mean residual percentage of meal was significantly greater than that of 48 healthy subjects, that is, 71.1 +/- 15.1 vs. 53.5 +/- 13.1% [means +/- SD; t (129) = 6.48, P < 0.0001]. The healthy individuals' mean residual percentage + 2 SD was exceeded in 22 patients. CONCLUSIONS: Slow gastric emptying in patients with type I diabetes seems related to the degree of autonomic neuropathy but not to peripheral neuropathy, actual blood glucose, and glycemic control.

Adult↗
PubMed1997

Acute response of pig skin to irradiation with 12C-ions or 200 kV X-rays.

The acute response of pig skin to treatment with high energy carbon ions (plateau region) at the Gesellschaft für Schwerionenforschung (GSI, Darmstadt, Germany) was compared with changes after 200 kV x-irradiation. Carbon doses isoeffective to the x-ray doses were computed with a recently established model for calculation of the biological effect of heavy ions. Clinical changes and physiological symptoms (blood flow, erythema, trans-epidermal water loss, skin hydration) were scored. The parameters analyzed were maximum and mean values of each symptom during days 24 to 70 after irradiation, and the quantal endpoints for the establishment of dose effect curves were the median values of these. With exception of the maximum change in the red blood cell concentration (p < 0.02) no significant differences could be found in the response to x-rays and RBE-corrected heavy ions. These results indicate that the model is valid for the calculation of biological effects of 12C-ions (plateau region) and may at least for epidermis be applied to treatment planning.

Animals↗
PubMed1997

[Quality assurance by patient surveys in medical rehabilitation: assessment and evaluation of rehabilitation structures and processes ("satisfaction of rehabilitation patients")].

Since 1994 Germany's statutory pension insurance schemes have been developing a multifaceted programme to assure and optimize the quality of their medical rehabilitation measures. One part aimed at developing a postal questionnaire for patients 8 to 12 weeks after rehab. It comprises two sections: one for the assessment of patients' perceptions and ratings in relation to rehab structures and processes, the other of changes of their health status. The article describes the development of the first part ("rehabilitee satisfaction"). We basically defined relevant sectors and qualities of medical rehab, analysing existing questionnaires, letters of complaint, results of expert interviews and patient focus groups. Mainly based on results from one large study of rehabilitees from two different pension insurance schemes (for blue or white collar workers), we report on psychometric properties of the final instrument, especially its contents, reliability, internal structure, validity and reference values. In February 1997, the instrument was accepted by the association of German pension schemes and may now be used in the routine phase of the quality programme, except for patients with psychosomatic disorders or substance abuse.

Activities of Daily Living↗
PubMed1996

Another heritage from the RNA world: self-excision of intron sequence from nuclear pre-tRNAs.

The intervening sequences of nuclear tRNA precursors are known to be excised by tRNA splicing endonuclease. We show here that a T7 transcript corresponding to a pre-tRNA(Tyr) from Arabidopsis thaliana has a highly specific activity for autolytic intron excision. Self-cleavage occurs precisely at the authentic 3'-splice site and at the phosphodiester bond one nucleotide downstream of the authentic 5'-splice site. The reaction results in fragments with 2',3'-cyclic phosphate and 5'-OH termini. It is resistant to proteinase K and/or SDS treatment and is not inhibited by added tRNA. The self-cleavage depends on Mg2+ and is stimulated by spermine and Triton X-100. A set of sequence variants at the cleavage sites has been analysed for autolytic intron excision and, in parallel, for enzymatic in vitro splicing in wheat germ S23 extract. Single-stranded loops are a prerequisite for both reactions. Self-cleavage not only occurs at pyrimidine-A but also at U-U bonds. Since intron self-excision is only about five times slower than the enzymatic intron excision in a wheat germ S23 extract, we propose that the splicing endonuclease may function by improving the preciseness and efficiency of an inherent pre-tRNA self-cleavage activity.

Arabidopsis↗