Biomedical subjects

U Meier

Publications and source records attributed to U Meier.

At least 73 records · Page 4Linked to original sources

PubMed1998

[Psychophysiology, signs and symptoms of disease the course of normal pressure hydrocephalus].

Between May 1982 until January 1997 we investigated 200 patients suspected for normal pressure hydrocephalus (NPH) by performing an intrathecal infusion test. According to our experiences gait ataxia is the leading symptom of NPH. Regarding dementia we could not find a significant difference compared to cerebral atrophy. Bladder incontinence can be characterised as a symptom of late-stage NPH. The complete Hakim trias should not be overestimated in differential diagnostic considerations. Graduation of NPH and cerebral atrophy after the results of the infusion test in an early and late stage enables prognostic evaluation of the course of disease. Patients with NPH in an early stage report in the follow-up on an improvement of their symptoms after shunt operation (65 percent of patients), whereas 50 percent of the patients with late stage NPH were improved. The computer-aided infusion test allows secure differentiation between patients with NPH and those with cerebral atrophy.

Humans↗

PubMed1998

[Possibilities of therapeutic photokeratotomy with the excimer laser in treatment of Schnyder crystalline corneal dystrophy].

PURPOSE: To evaluate the efficacy of excimer laser phototherapeutic keratectomy (PTK) in treating the Schnyder cristalline corneal dystrophy. METHODS: We examined the members of three generations of a family affected by Schnyder crystalline dystrophy. Two patients with disabling visual acuity were treated with PTK. RESULTS: The best corrected visual acuity (BCVA) of the patient with the cristalline form of the dystrophy progressed from 20/70 to 20/25. The BCVA of the other patient affected by the sine crystals form of the Schnyder dystrophy progressed from 20/70 to 20/30. CONCLUSIONS: Excimer laser photokeratectomy is a valuable tool in treating the Schnyder cristalline form of corneal dystrophy.

Adult↗

PubMed1998

[Fractures of the lower cervical spine. Surgical methods and long-term outcome].

Between 1980 until 1996 we operated altogether 327 patients because of a discoligamentous or osseous injury of the lower cervical spine. In a retrospective examination we evaluated the type of the injuries, the mechanism of the accidents, the neurological status on admission and the postoperative result. With regard to the long-term results we re-investigated 170 patients who have been operated on in our Department of Neurosurgery. In none of the patients we could find a neurological deterioration after the operation. The prognosis for patients with an incomplete and complete transversal syndrome is worse concerning a regression of the neurological deficit. The ventral spondylodesis in the technique according to Cloward-Crock, Robinson and Smith and Bailey-Badgley with ventral plate fixation provided the best results and we recommend these techniques for injuries of the lower cervical spine.

Adolescent↗

PubMed1998

[Clinically suspected normal-pressure hydrocephalus diagnosis--current status of diagnosis and therapy].

Since the first description of the disease normal pressure hydrocephalus (NPH), there has been a great progress in the diagnosis of this disease. Taking into account that the age of the population is rising the incidence and social medical importance is increasing. Modern neuroradiological techniques are visualising a ventricular enlargement but a definitive diagnosis cannot be drawn. The intrathecal infusion tests represent a save and valid tool while measuring the cerebrospinal fluid dynamics. Shunting is the only possible therapy in NPH. Complications from shunting are still a great problem and therefore, a definite diagnosis must be gained in order to avoid a shunt induced morbidity and mortality.

Cerebral Ventricles↗

PubMed1997

[Diagnosis of normal pressure hydrocephalus. A calculation model for determining intracranial pressure-dependent resistance and compliance].

Computer-aided analysis of the results of the intrathecal infusion test using our mathematical computation leads to simplification of this investigation, and therefore normal pressure hydrocephalus is more easily diagnosed. Simultaneous measurement of resistance and compliance during a single investigation allows the exertion of the patients to be minimized. In contrast to classic methods it is not necessary that the ICP reaches a plateau. Our mathematical method diverges with the description of a pressure-dependent slope of the function for the resistance from the static examination models. For that we are able to take the non-linearity of the cerebrospinal fluid resorption into consideration. The intrathecal infusion tests is a reliable diagnostic method for measuring resistance and compliance in patients suspected of having normal pressure hydrocephalus.

Cerebral Ventricles↗

PubMed1997

[Violence in the school--analysis of the problem and possible interventions].

This article deals with a topic being controversially discussed in public for several years now: violence in school. Following the outlining of the current state of research and the naming of causes is a representation of the research-project "Violence in School' sponsored by the German Research Community (Deutsche Forschungsgemeinschaft, DFG). This four-stage program which was designed to analyze and prevent violence in school has set itself the aim to get a comprehensive idea of extent and appearance of violent behavior as well as to find condition-constellations in the school environment and also externally. Finally, some ideas for prevention and intervention of violence in school are given. Those recommendations represent a set of proposals that can be found in the bibliography.

Adolescent↗

PubMed1995

Identification of cyclophilin A from human decidual and placental tissue in the first trimester of pregnancy.

The protein patterns of tissue homogenates from human decidua and placenta of first trimester pregnancies were investigated. Particular attention was paid to the low molecular weight components of these tissues, since substantial evidence has accumulated that some of these smaller proteins show a characteristic cyclic and pregnancy expression. Two specific bands were purified from homogenates of first trimester decidua and placenta using gel filtration and anion exchange chromatography. These bands were separated by gel electrophoresis and blotting onto polyvinylidendifluoride membrane. Partial amino acid sequencing of both proteins revealed sequences identical to human cyclophilin A. One protein was sequenced V-N-P-T-V-F-F-D-I-A-V-D-G-E-P-L-G-R-(X)-S-F-E-L-F-A-D-K-V-P and identified as the 17 kDa isoform of cyclophilin A. The other protein was sequenced V-N-P-T-V-F-F-D-I-A and identified as the 18 kDa isoform of cyclophilin A.

Amino Acid Isomerases↗

PubMed1994

Diterpene glycosides from Iphiona aucheri.

Iphiona aucheri is responsible for poisoning racing camels (Camelus dromedarius) in the United Arab Emirates U. A. E. Terpenoids, a non-toxic pyrrolizidine alkaloid and two diterpene glycosides, atractyloside and carboxyatractyloside, were isolated and their structures determined by spectroscopic methods. Atractyloside and carboxyatractyloside were identified as the toxic principle of the plant.

Animals↗

PubMed1994

Prognostic factors and outcome of incompletely resected invasive thymoma following radiation therapy.

BACKGROUND: Stage III and stage IV thymomas with significant macroscopic infiltration to the neighboring structures are rarely completely resectable. It therefore remains unclear to what extent tumors must be surgically debulked to improve prognosis. PATIENTS AND METHODS: We reviewed the cases of 31 patients with incompletely resected invasive thymoma and residual macroscopic disease who were referred to postoperative irradiation. Survival and local tumor control were analyzed. All patients were treated between 1958 and 1990 with megavoltage irradiation at doses ranging from 42 to 66 Gy. The shortest follow-up time for living patients was more than 5 years. RESULTS: The overall median 5-year survival rate was 45%. Eighteen stage III patients had a 5-year survival rate of 61% and a 10-year survival rate of 57%. Thirteen patients had stage IV disease and 5- and 10-year survival rates of 23% and 8%, respectively. Univariate and multivariate analyses confirmed a worse prognosis for stage IV disease. Epithelial or spindle-cell thymoma was associated with stage IV disease. Twenty-two percent of patients with stage III disease had epithelial or spindle-cell thymoma, versus 69% of patients with stage IV disease (P = .02 for univariate and P = .05 for multivariate analysis). Initial tumor diameter greater than 10 cm correlated with poor prognosis in the univariate analysis (P = .05). However, more importantly, debulking of tumor did not significantly improve outcome when compared with patients who received biopsy only. The median survival rate of patients with stage IVa disease did not differ from that of those with stage IVb disease. Mediastinal control was achieved in 23 patients (74%). Stage IV disease did not correlate with an increase in local treatment failure after irradiation, although epithelial or spindle-cell thymoma predisposed for local treatment failure (46% v 11%; P = .04 in univariate and P = .055 in multivariate analysis). CONCLUSION: Tumor debulking leaving macroscopic residual thymoma, as opposed to biopsy alone, does not improve prognosis when followed by radiation. Radiation therapy for local tumor control is most effective in nonepithelial-predominant thymomas.

Adult↗

PubMed1994

[Surgical outcome after severe craniocerebral trauma in childhood and adulthood. A comparative study].

During a period of 15 years 1123 patients were operated on for severe head injury in our Department of Neurosurgery. We evaluated 936 patients (83%) on the basis of the Glasgow coma scale and the Glasgow outcome scale and allocated them into four groups by diagnosis and also grouped them by age. The 170 patients in the groups of children and adolescents (15%) were compared with the adults, and the features characterizing the causes of the accidents and the prognosis were analysed. Young patients and adults with epidural haematomas or perforating head injuries had a better prognosis than patients with acute subdural haematomas or brain contusions. The postoperative results after severe head injuries in children and adults were the same as in the group with an initial rating of 3-5 points and 9-15 points on the Glasgow coma scale. Only the group of children with 6-8 points on the Glasgow coma scale on admission had better results than the adults. The reason for this might be the greater plasticity of the brain in childhood.

Adolescent↗

PubMed1993

Fiber regeneration in nerve grafts without connection to a target muscle: an experimental study in rabbits.

In 30 rabbits, both saphenous nerves were harvested as autografts and coapted to the branch for the rectus femoris muscle without connection to any distal target muscle. The graft from the right thigh was led to the contralateral extremity (crossover grafting). The graft on the left side remained on the same extremity (ipsilateral grafting). Animals were separated into four groups and were sacrificed 3, 6, 9, and 12 months after grafting. Specimens of the grafts and the donor motor branches were harvested for histomorphometric examination. The number of myelinated nerve fibers in the distal end of the nerve grafts was significantly increasing from 3 to 6 months after grafting and remained on a relatively constant level in the long-term groups. Three months after the first operation, greater numbers of myelinated nerve fibers were counted after ipsilateral grafting than after crossover grafting. In the long-term groups, this difference could not be observed.

Animals↗

PubMed1993

The reduction of nitrous oxide to dinitrogen by Escherichia coli.

Escherichia coli K12 reduces nitrous oxide stoichiometrically to molecular nitrogen with rates of 1.9 mumol/h x mg protein. The activity is induced by anaerobiosis and nitrate. N2-formation from N2O is inhibited by C2H2 (Ki approximately 0.03 mM in the medium) and nitrite (Ki = 0.3 mM) but not by azide. A mutant defective in FNR synthesis is unable to reduce N2O to N2. The reaction in the wild type could routinely be followed by gas chromatography and alternatively by mass spectrometry measuring the formation of 15N2 from 15N2O. The enzyme catalyzing N2O-reduction in E. coli could not be identified; it is probably neither nitrate reductase nor nitrogenase. E. coli does not grow with N2O as sole respiratory electron acceptor. N2O-reduction might not have a physiological role in E. coli, and the enzyme involved might catalyze something else in nature, as it has a low affinity for the substrate N2O (apparent Km approximately 3.0 mM). The capability for N2O-reduction to N2 is not restricted to E. coli but is also demonstrable in Yersinia kristensenii and Buttiauxella agrestis of the Enterobacteriaceae. E. coli is able to produce NO and N2O from nitrite by nitrate reductase, depending on the assay conditions. In such experiments NO2- is not reduced to N2 because of the high demand for N2O of N2O-reduction and the inhibitory effect of NO2- on this reaction.

Anaerobiosis↗

PubMed1993

[Relations between donor nerve size and degree of neurotization in the nerve transplant--an experimental study].

The present study was undertaken to investigate whether the number of myelinated fibers in a sensory nerve used as an autograft influences the result of nerve fiber regeneration in the graft. In 30 rabbits, the left saphenous nerve was used as an autograft. It was coapted to the motor branch to the rectus femoris muscle. Biopsies from both ends of the graft were taken. Animals were separated into four investigation groups, which were reexamined 3, 6, 9 and 12 months after the grafting procedure. Biopsies for histological and morphometric examination were again taken from the proximal and the distal part of the grafts. Thus, the number of myelinated nerve fibers in the different specimens could be obtained by computer-assisted image analysis. At the proximal end of the original saphenous nerve, the number of fibers varied between 1032 and 3100 (mean 2145). Corresponding data obtained from the distal end ranged from 1044 to 3084 myelinated nerve fibers (mean 1724). Fiber numbers in the proximal and distal parts of the grafts before and after regeneration were correlated to each other. In the whole population of specimens (correlation coefficient +/-0) as well as in the experimental subgroups, the quantitative success of neurotization in the grafts did not depend to a high degree upon the fiber numbers in the original saphenous nerve. The correlation coefficient for the proximal part of the graft exceeded 0.5 to only three and twelve months after grafting, but did not reach a level of statistical significance. In the distal part of the graft, the coefficient for a linear correlation was always less than 0.45.

Animals↗

PubMed1992

The traumatic dural sinus injury--a clinical study.

In a period of 13 years 978 cases of severe head injuries were operated on in our clinic. An analysis of the medical reports includes injuries of the superficial dural sinus (39 cases = 4%): among these injuries of the anterior and central part of the superior sagittal sinus (66 per cent), injuries of the transverse sinus (18 per cent), injuries of the posterior part of the superior sagittal sinus (8 per cent), and combined injuries of different dural sinuses (8 per cent). Clinical data, i.e. the causes of accident, radiological examination results, intracranial lesions, operation techniques and outcome are analysed and discussed. The analysis of cases with dural sinus injuries shows a high mortality rate (total mortality rate: 16 patients = 41%; intra-operative mortality rate: 8 patients = 20%).

Adolescent↗

PubMed1992

[Rupture of the Achilles tendon--fibrin gluing or suture?].

The rise of recreational sports activities and the incidence of ruptures of the Achilles tendons has increased simultaneously. Recently the use of fibrin sealing for surgical therapy of ruptured Achilles tendons has emerged as an alternative technique. Between 1982 and 1989 62 consecutive patients were operated for unilateral Achilles tendon rupture. Following causes for ruptures are known: 36 indirect traumas in sport (74%), 9 direct blunt injuries at occupational work (18%), 3 traffic-accidents (11%) and 1 rupture after operation of a Haglund exostosis. 25 patients (56%) were treated by suture technique and 20 patients (44%) with fibrin sealant. The mean long term follow-up of 49 months is known of 49 patients. There were 3 (12%) postoperative infections in the suture group and none in the fibrin group. After suturing the Achilles tendon 3 (12%) reruptures occurred 8-10 weeks after tendon repair and 1 (5%) rerupture after fibrin sealing. All reruptures are caused by a new adequate trauma. The time of return to social and recreational activities was 9 months in the suture group and 7 months in the fibrin group. The functional and cosmetic results after use of fibrin was significant better, and the long-term results were very satisfactory. We prefer fibrin sealing for the treatment of acute ruptures of Achilles tendons.

Achilles Tendon↗

PubMed1991

[Aspects of rehabilitation after early stabilization of complex injury of the cervical spine].

Within the scope of catamnestic investigation and a follow-up examination 170 fractures of the cervical spinal cord, operated in a period of 8 years, were explored. Dependent on the neurological starting point the length of stay in hospital, the time of temporary disablement and the results of social rehabilitation were evaluated. The examination results are appraised.

Activities of Daily Living↗

PubMed1991

[Postoperative results following severe craniocerebral trauma].

918 patients were operated because a severe head injury in our Neurotraumatological Clinic during a period of 12 years. 733 patients (80 per cent) could been evaluated as well with regard to the Glasgow Coma Scale and the Glasgow Outcome Scale as analysed in four diagnose groups corresponding to the period of live. Patients with epidural haematoma and open head injuries showed a better forecast than patients with acute subdural haematoma. Those with contusion of the brain and less than 8 points in the Glasgow Coma Scale or those in a higher age had a bad prognosis.

Adolescent↗

PubMed1991

[Results of the surgical management of frontobasal injuries].

The author reports about 183 patients with frontobasal injuries. 50 per cent of them were operated immediately because open injuries or intracranial complications. The other half was operated in an interval of 5 to 10 days after injury. The localisation of the frontobasal lesion, clinical results according to the Glasgow Coma Scale and Glasgow Outcome Scale as well as the operation methods are demonstrated and discussed. The operative closure of the dura failure with an unipedicled periosteal flaps ensures good results in the most cases.

Brain Injuries↗