Search PubMed⌕ Search

Biomedical subjects

R Urban

Publications and source records attributed to R Urban.

At least 73 records · Page 4Linked to original sources
PubMed1983

Total surface hip arthroplasty in dogs using a fiber metal composite as a fixation method.

A total hip surface replacement was performed on 13 adult mongrel dogs using a porous fiber metal composite for fixation to bone. Titanium fiber composite rings were molded onto cylindrical acetabular prostheses, and cobalt-chrome fiber inserts were sintered onto the cast cobalt-chrome femoral components. The animals were allowed unrestricted walking. Four dogs were sacrificed between 3 and 5 weeks, five at 7 weeks, one with a femoral neck fracture at 12 weeks, and three at 26 weeks. Bone ingrowth was accomplished in 20 of the 26 prosthetic components. This included 12 femoral components and eight acetabular. The main reason for failure appeared to be inadequate primary fixation, secondary to either poor design or technical difficulties experienced during the surgical procedure.

Animals↗
PubMed1983

A canine cementless total hip prosthesis model.

To evaluate a porous fiber titanium composite as a fixation method, total hip arthroplasty was performed in 13 large male mongrel dogs. In seven both acetabular and femoral composites were fixed with a porous titanium fiber composite, and in the other six the acetabulum was fixed with acrylic cement. The animals were killed one, three, and six months following implantation. At autopsy all components were fixed by bony ingrowth. There was progressive remodeling of the ingrown bone and of the bone trabeculae surrounding the prosthesis in the three- and six-month animals, with gradual thickening and development of haversian structures. Cortical osteoporosis, which did not appear to be progressive, was detected in both the one- and six-month specimens.

Acetabulum↗
PubMed1978

[Clinical trial of mepiprazol in the treatment of neurotic inpatients (author's transl)].

Within a controlled double-blind clinical trial the psychopharmacological effect of mepiprazole was tested against placebo in the treatment of neurotic inpatients. Some results of the recorded psychophysiological parameters (tremor, reaction time and flicker fusion threshold) as well as the scores on a symptom checklist for neurotic patients (post hoc divided into three scales by means of factor analysis: anxiety, depression and weaping) indicate a tranquilizing effect of mepiprazol. These findings are discussed critically with regard of methodological problems of testing tranquilizers in psychiatric hospitals.

Adolescent↗
PubMed1978

[Relationship between perazine serum concentration and clinical results in long-term treated schizophrenic outpatients (author's transl)].

The perazine serum concentration was determined with a new gaschromatographic method in 33 schizophrenic outpatients of our psychiatric catamnestic unit who had received perazine for a period of 18 years. A very high constancy of the perazine serum level could be demonstrated by repeated measurements. A close connection existed between perazine dosage and perazine serum level. Both findings suggest a very good complicance of these patients. Serum levels were correlated positively with the intensity of the psychopathologic symptoms as well as with the frequency of side-effects, particularly with slight changes of liver enzymes.

Adolescent↗
PubMed1978

[Asymmetric synthesis with unlimited stereoselectivity--the synthesis of isomer-free peptide derivatives by stereoselective four-component condensation (author's transl)].

The development of methods for the synthesis of peptides by stereoselective four-component condensations led to new ways to prepare pure chiral chemical compounds with high yield by asymmetric syntheses. A scheme of asymmetric syntheses is described, which begins with a productively stereoselective synthesis affording a high yield of the desired product, accompanied by a minor amount of a diastereomeric byproduct. This is converted into an easily removable non-isomeric compound by a subsequent reaction with unlimited destructive stereoselectivity which is due to non-linear effects. In general, only small losses of the main product occur during the latter step. The efficiency of such asymmetric syntheses is enhanced by the use of chiral templates which can be recycled. As an illustration we describe the synthesis of a stereoisomer-free tetravaline derivative by a productively stereoselective four-component condensation, followed by conversion of the contaminating diastereoisomer into an easy to remove non-isomeric compound by destructively stereoselective partial acidolysis which yields the main product in 73% and with a purity of greater than 99.98%.

Methods↗