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Biomedical subjects

R T Müller

Publications and source records attributed to R T Müller.

At least 37 records · Page 2Linked to original sources
PubMed1997

The frequency, prognosis and significance of nerve injuries in total hip arthroplasty.

Although the incidence of post-operative nerve palsy after total hip replacement is rare, it is an important complication for the patient. In a retrospective study the results of 2713 hip arthroplasties were reviewed. Sixty-one cases (2.24%) of post-operative neuropathy were identified. 13 of the sciatic nerve, 33 of the peroneal nerve and 15 of the femoral nerve. The risk is significantly higher in revisions (3.06%), especially when exchanging the acetabular component (8.5%) rather than in primary arthroplasties (2.13%). After an average period of 107 months (11-240) from operation, 41 patients with nerve lesions were questioned about their subjective functional capacity: 17% had recovered completely, 39% had noticed an improvement, and in 44% there was no change; 56.1% complained of weakness and had a complete paralysis. In all cases there was dysfunction of sensibility. Another 17.1% had a sensibility defect without weakness. There was pain in 51.2%, paraesthesia in 34.1% and areas of complete anaesthesia in 19.5%. Altogether 61% of the 41 patients had either gait problems or were dependent on orthotic devices. In summary, only about a third of the patients studied achieved a satisfactory degree of functional recovery.

Female↗
PubMed1997

The rat myosin myr 5 is a GTPase-activating protein for Rho in vivo: essential role of arginine 1695.

myr 5 is an unconventional myosin (class IX) from rat that contains a Rho-family GTPase-activating protein (GAP) domain. Herein we addressed the specificity of the myr 5 GAP activity, the molecular mechanism by which GAPs activate GTP hydrolysis, the consequences of myr 5 overexpression in living cells, and its subcellular localization. The myr 5 GAP activity exhibits a high specificity for Rho. To achieve similar rates of GTPase activation for RhoA, Cdc42Hs, and Rac1, a 100-fold or 1000-fold higher concentration of recombinant myr 5 GAP domain was needed for Cdc42Hs or Rac1, respectively, as compared with RhoA. Cell lysates from Sf9 insect cells infected with recombinant baculovirus encoding myr 5 exhibited increased GAP activity for RhoA but not for Cdc42Hs or Rac1. Analysis of Rho-family GAP domain sequences for conserved arginine residues that might contribute to accelerate GTP hydrolysis revealed a single conserved arginine residue. Mutation of the corresponding arginine residue in the myr 5 GAP domain to a methionine (M1695) virtually abolished Rho-GAP activity. Expression of myr 5 in Sf9 insect cells induced the formation of numerous long thin processes containing occasional varicosities. Such morphological changes were dependent on the myr 5 Rho-GAP activity, because they were induced by expression the myr 5 tail or just the myr 5 Rho-GAP domain but not by expressing the myr 5 myosin domain. Expression of myr 5 in mammalian normal rat kidney (NRK) or HtTA-1 HeLa cells induced a loss of actin stress fibers and focal contacts with concomitant morphological changes and rounding up of the cells. Similar morphological changes were observed in HtTA-1 HeLa cells expressing just the myr 5 Rho-GAP domain but not in cells expressing myr 5 M1695. These morphological changes induced by myr 5 were inhibited by coexpression of RhoV14, which is defective in GTP hydrolysis, but not by RhoI117. myr 5 was localized in dynamic regions of the cell periphery, in the perinuclear region in the Golgi area, along stress fibers, and in the cytosol. These results demonstrate that myr 5 has in vitro and in vivo Rho-GAP activity. No evidence for a Rho effector function of the myr 5 myosin domain was obtained.

Actins↗
PubMed1996

Cytotoxicity of phenol to musculoskeletal tumours.

Local treatment with phenol is often used after intralesional excision of chondroblastomas and giant-cell tumours which involve bone near joints, and has been shown to reduce the rate of recurrence. The ideal concentration of phenol is uncertain, but may be important because of the high rate of absorption and toxicity. We have studied the effectiveness of different concentrations on standard sarcoma cell lines. Our results suggest that a 5% solution of phenol is effective against dispersed single cells, and that higher concentrations give no significant advantage, but create problems due to lack of homogeneous mixing, temperature and safety.

Bone Neoplasms↗
PubMed1995

Localization of the rat myosin I molecules myr 1 and myr 2 and in vivo targeting of their tail domains.

Myr 1 is a widely distributed mammalian myosin I molecule related to brush border myosin 1. A second widely distributed myosin I molecule similar to myr 1 and brush border myosin I, called myr 2, has now been identified. Specific antibodies and expression of epitope-tagged molecules were used to determine the subcellular localization of myr 1 and myr 2 in NRK cells. Myr 1 was detected at the plasma membrane and was particularly enriched in cell protrusions like lamellipodia, membrane ruffles and filopodia. In dividing cells myr 1 localized to the cleavage furrow. Myr 2 was localized in a discrete punctate pattern in resting cells and in cells undergoing cytokinesis. In subcellular fractionation experiments myr 1 and myr 2 were both partly soluble and partly associated with smooth membranes of medium density. The tail domains of myosin I molecules have been proposed to interact with a receptor and thereby determine the subcellular localization. To test this hypothesis we expressed the tail domains of myr 1 and myr 2 that lack the F-actin-binding myosin head domain in NRK cells. These tail domains also partly copurified with smooth membranes of medium density and immunolocalized similar to the respective endogenous myosin I; however, they exhibited a lower affinity for membranes and an increased diffuse cytosolic localization. These results suggest that the tail domains of myr 1 and myr 2 are sufficient for subcellular targeting but that their head domains also contribute significantly to maintaining a proper subcellular localization.

Actins↗
PubMed1994

Quality of bone transplantation procedure in West German orthopaedic hospitals.

We examined the impact of standardisation of allogenous bone transplantation according to the HIV protection guidelines on procedure quality using a questionnaire. As far as preparation, storage temperature and safety of the transplant are concerned, we showed an improvement in comparison to previous records. Hepatitis C testing has fallen although it is currently being recommended. According to the risk estimate for donors over 60 years the 3-months HIV test was considered unnecessary and was carried out in only 50% of transplants. In 4.5% of transplants no precautions against HIV transmission were taken.

AIDS Serodiagnosis↗
PubMed1989

Long-term results of the Girdlestone hip.

The Girdlestone hip is a possible alternative in cases where reconstruction and reimplantation appear hopeless. Only a minority of the 22 patients we followed for up to 16 years have had results ranging from good to satisfactory.

Aged↗
PubMed1986

[Management strategy in severe craniocerebral trauma in a general surgical department].

Emergency treatment of severe head injury combined with multiple trauma in most cases must be performed in regional hospitals and in general surgical units. Especially in acute intracranial hemorrhage (epidural hematoma) with the urgent indication to craniotomy the transmission of the patient in a special neurosurgical department is not possible in an adequate time. Therefore general surgeons should be trained in emergency trepanation of the skull and in basic treatment of severe head injury including measuring of intracranial pressure. The tactics of treatment of severe cranio-cerebral trauma is demonstrated on 46 cases out of 869 patients with head injury treated in our hospital from 1981 to 1984.

Adult↗
PubMedDate not supplied

[Complete dislocation of the polyethylene inlay after internal hemipelvectomy and individually fitted tumor endoprosthesis].

We report about an exceptional complication after internal hemipelvectomy and replacement of the defect with a custom-made endoprosthesis. A complete luxation of the PE-inlay out of the metal cup occurred. Radiologically we assumed a luxation of the femoral head in dorsal direction. Revision after a failed attempt of closed reposition showed a complete luxation of the inlay, which was caused by deficient fixation in the acetabular component. The absence of a contrast wire in the PE-inlay delayed the right diagnosis and made it difficult to find the dislocated inlay in the large wound.

Bone Neoplasms↗
PubMedDate not supplied

[Survival rate of a cement-free cup of titanium with laser structured surface].

PURPOSE: So far no clinical results concerning the survival rates of cementless pure titanium cups with laser-structured surfaces exist. This study was performed to evaluate our results for the Alphasegment acetabular component (Alphanorm). METHOD: Retrospective analysis of 50 cups in 45 patients was performed (operations performed between November 1995 and January 1998). The average age at the time of the implantation was 65.1 years. Dysplastic hips and revisions were excluded. The survival rate was calculated according to the Kaplan-Meier analysis with the end point defined as the revision surgery of the cup. RESULTS: The average follow-up period was 2.9 (0.6-4.0) years. Two patients (i.e., two implants) died during the observation period, none were lost for follow-up. Six of the cups had to be revised due to aseptic loosening. The survival rate at 3.2 years after implantation was 87%. None of the stems had to be revised. CONCLUSIONS: Further use of the cementless hemispherical pure titanium cup with laser-structured surface cannot be recommended. The observed prevalence of loosening for the Alphasegment acetabular components was higher than for other cups. Close follow-up of patients with this type of implant is necessary.

Acetabulum↗
PubMedDate not supplied

[Primary hip- and knee arthroplasty--comparison of the actual costs with the Australian diagnosis related groups (DRG)-].

AIM: With the introduction of the Australian DRG system in Germany the question arises which current procedures remain reasonable in cost. The present study compares the actual costs with the expected DRG reimbursement. PATIENTS AND METHODS: Prospective analysis of 23 patients with primary hip and 26 with knee arthroplasty was performed to identify all cost factors during the hospitalization period including all applied measures. Retrospective analysis was carried out of the additional costs of relevant concomitant diseases (liver transplantation, haemophilia). RESULTS: Expenses of 6231 euro; for hip and 6453 euro; for knee implants were covered by the DRG reimbursement. Although a special reimbursement was paid, the additional costs of the concomitant diseases resulted in a financial loss. CONCLUSION: To cover the current costs for patients free of complications, an enormous reduction of the length of stay is required. Otherwise complicated cases may result in a loss of quality or selection of patients. The present cost analysis outlines a guideline for an individual calculation and assessment of the necessary DRG reimbursement.

Adult↗
PubMedDate not supplied

[Quality and management of preoperative patient information. Results of conventional and computer based documentation].

INTRODUCTION: Analysis of the quality of different modes of preoperative information management on the example of primary total hip arthroplasty. Comparison between a since 10 years used, computer based system and a conventional procedure with additional hand-written notes. METHODS: Retrospective analysis of respectively 50 with conventional and computer based system written preoperative patient information. The completeness of the documentation is examined according to the demands of current judgement. RESULTS: The results confirm, independent from the level of education, a complete documentation of all risks by applying the computer based system, whereas the conventional method leads to considerable lacks of documentation. DISCUSSION: The computer based system guarantees a high quality of preoperative patient information which cannot be obtained by the conventional method and therefore offers a protection against unjustified claims of liability.

Ambulatory Care Information Systems↗
PubMedDate not supplied

[Nerve lesions after hip prosthesis implantation--fate or treatment error?].

INTRODUCTION: Nerve lesions after hip arthroplasty are common complications which may imply the reproach of a treatment mistake. Thus, the decisive question to the expert runs: fate or treatment mistake? METHODS: Retrospective analysis of all cases dealt with at the medical expert commission of the General Medical Council Nordrhein during 1977-1997 in respect of the damage mechanisms and expert judgments. RESULTS: As long as diagnosis and therapy were set on time, nerve lesions after hip arthroplasty due to extension, pressure or placement of the leg were evaluated as fateful (81%). Delayed treatment as well as incorrect operation technique, -indication, or inadequate documentation were judged as a treatment mistake (19%). CONCLUSION: Nerve lesions after hip arthroplasty cannot always be avoided and thus do not directly imply a treatment mistake. Immediate therapy and precise documentation are important to minimize the damage.

Arthroplasty, Replacement, Hip↗
PubMedDate not supplied

[Analysis and assurance of complete medical documentation].

A written report on the findings of the examination forms the basis for the further procedure in the treatment of a patient--not merely in the area of orthopaedics. The examination findings should, therefore, be legible, readily understandable and complete. On the basis of 600 individual findings established at admission in the case of inpatients with diseases of the spine and hip, stemming from a total of three hospitals, the behaviour pattern of the individual examiner is analysed along with deficiencies in documentation. For a number of significant deficits, differences in the particular emphasis applied by individual physicians during the examination, the fact that the time available for such examinations is usually limited, and the lack of documentation system, are probably responsible.

Data Collection↗
PubMedDate not supplied

[Assurance and proof of satisfactory and complete information].

To prevent unjustified blame and claims enforced by patients, is necessary to prove evidence of an indisputable and complete preoperative information. With the help of our developed software it takes little effort to satisfy the given demands.

Female↗