Biomedical subjects

M Pfeiffer

Publications and source records attributed to M Pfeiffer.

130 records · Page 8Linked to original sources

PubMedDate not supplied

[Valgisation tibial head alignment osteotomy--results of a comparative follow-up of Coventry interligament tibial head osteotomy and Wagner oblique osteotomy].

In the follow-up study presented the results of 33 high tibia-osteotomies (Coventry) are compared with 51 oblique lower tibia-osteotomies (Wagner). Both techniques guarantee a safe improvement of function, pain relief, and biomechanic situation of the arthrotic joint. The results are mainly independent of the grade of joint involvement and the age of the patient. The Coventry-osteotomy tends to accentuate femoropatellar arthrotic destruction, while the Wagner-osteotomy does so in 20% fewer cases. The functional improvements of the Wagner-osteotomy are more than 20% better, up to 5 years postoperatively, when compared with the high tibia-osteotomy. Indication, technical performance of the operation, and the postoperative care are discussed in the light of the results presented.

Adolescent↗

PubMedDate not supplied

Testing medical disposables using the Limulus Amoebocyte Lysate (LAL) test.

Plastic, single-use devices intended for the administration of drugs or for the removal or transfer of body fluids must be free of pyrogenic contaminants. Unfortunately, very little information is available regarding tests to detect such contaminants. For this reason, many manufacturers of medical disposables must rely on their own discretion when they devise methods for extracting these substances from their products. This article discusses the use and value of the Limulus Amoebocyte Lysate (LAL) test for estimating the concentration and extraction of bacterial endotoxins in disposable medical devices. When bioburden-control procedures are applied to products manufactured to GMP requirements, batch testing of products for pyrogenicity may not be essential.

Animals↗

PubMedDate not supplied

The influence of gastrointestinal agents on resorption and metabolism of cyclosporine after heart transplantation: experimental and clinical results.

The clinical effectiveness of cyclosporine is limited by changes in resorption and metabolism of cyclosporine and by possible drug interactions. This study examined the influence of five gastrointestinal agents on duration and resorption of cyclosporine and dosage/level relations: cimetidine, famotidine, pirenzepine, aluminum hydroxide, and omeprazole. These gastrointestinal agents were studied in 64 rat experiments, in which the impact of each single drug and of drug combinations on cyclosporine resorption and metabolism was tested. A standardized dosage of cyclosporine was given orally, and the duration was calculated for the maximum whole blood level of cyclosporine to be achieved; the dosage/level quotient was calculated. Cimetidine, famotidine, pirenzepine, and combination treatment prolonged duration of cyclosporine resorption. Furthermore, cimetidine, famotidine, and omeprazole lowered the dosage/level quotient, thus leading to higher cyclosporine levels with the same dosage; pirenzepine increased the dosage/level quotient. For clinical comparison, 163 heart transplant patients who had received standard triple-drug immunosuppressive therapy were analyzed. The time interval until a therapeutic cyclosporine level was achieved and the dosage/level quotient were once again calculated. Similar to the results in the animal experiments, cimetidine and famotidine significantly delayed the resorption of cyclosporine; cimetidine, famotidine, and omeprazole lowered the cyclosporine dosage/level quotient, thus leading to higher cyclosporine levels with the same dosage. Aluminum hydroxide did not lead to any changes in the resorption or metabolism of cyclosporine. Most examined gastrointestinal agents, and particularly H2-blocking drugs, led to significant prolongation of cyclosporine resorption and cyclosporine level alterations. The initial prolongation of cyclosporine resorption was successfully avoided by intravenous administration of cyclosporine for the first 4 postoperative days in 40 consecutive patients.

Absorption↗

PubMedDate not supplied

An all sulfur analogue of the smallest subunit of F420-non-reducing hydrogenase from Methanococcus voltae--metal binding and structure.

The 25 amino acid long subunit VhuU of the F420-non-reducing hydrogenase from Methanococcus voltae contains selenocysteine within the consensus sequence of known [NiFe] hydrogenases DP(C or U)CxxCxxH (U = selenocysteine). The sulfur-analogue VhuUc was chemically synthesized, purified and its metal binding capability, the catalytic properties, and structural features were investigated. The polypeptide was able to bind nickel, but did not catalyse the heterolytic activation of H2. 2D-NMR spectroscopy revealed an alpha-helical secondary structure for the 15 N-terminal amino acids in 50% TFE. Nickel only binds to the C-terminus, which contains the conserved amino acid motif. Structures derived from the NMR data are compatible with the participation of both sulfur atoms from the conserved cysteine residues in a metal ion binding. Structures obtained from the data sets for Ni.VhuUc as well as Zn.VhuUc showed no further ligands. The informational value for Ni.VhuUc was low due to paramagnetism.

Amino Acid Sequence↗