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Biomedical subjects

M Aebi

Publications and source records attributed to M Aebi.

At least 181 records · Page 10Linked to original sources
PubMed1985

Nonconsensus branch-site sequences in the in vitro splicing of transcripts of mutant rabbit beta-globin genes.

Mutants of the rabbit beta-globin gene lacking the natural site of branch formation in the second intervening sequence have been analyzed for in vitro splicing activity. RNAs transcribed from these mutants were spliced, via lariat formation, at a reduced rate compared to wild-type RNA. The sites of branch formation were mapped by direct RNA analysis and primer-extension analysis. The sequences at the branch sites in the three mutants examined did not conform to the previously determined consensus sequence, nor were the 5' splice sites and branch sites complementary.

Animals↗
PubMed1985

[Experimental studies on artificial prostheses in microvascular surgery].

The need for microvascular grafts in replantation and free tissue transfer is well recognized. Variable results are reported in the literature. Therefore, an experimental study was undertaken to assess the suitability of an expanded PTFE (Polytetrafluoro-ethylene) as a microvascular graft. A 2.0 mm diameter graft was implanted in the artery and the vein of the rabbit. No graft in the venous system remained patent. From these animal experiments we conclude that there is no clinically applicable synthetic micro-graft available.

Animals↗
PubMed1984

Expression of an artificial yeast TRP-gene cluster in yeast and Escherichia coli.

All five tryptophan biosynthetic genes of Saccharomyces cerevisiae were unified on plasmid pME554, which is based on 2 micrometer DNA and pBR322 sequences allowing for autonomous replication in yeast and E. coli. Homologous and heterologous expression of this artificial yeast TRP-gene cluster was studied. Plasmid pME554 allowed for nearly normal growth of a yeast strain bearing auxotrophic mutations in all five TRP-genes. The plasmid-borne genes TRP2 to TRP5 were expressed and regulated normally in the frame of the general control. Gene TRP1, carried on an EcoRI/Bg/II fragment lacking the ARS1 function, was expressed poorly and did not respond to the general control like the chromosomally-borne TRP1 gene. Plasmid pME554 allowed for poor growth of E. coli strain W3110 tna- delta trpEA2 on minimal medium. Marked stimulation was observed, however, when anthranilic acid or indole were added. Accordingly, poor expression of the first Trp-enzyme anthranilate synthase and the last enzyme tryptophan synthase was found, whereas the other three genes were moderately well expressed in E. coli.

Base Sequence↗
PubMed1982

Operative stabilisation of dislocations, fractures and fracture-dislocations of the cervical spine.

A retrospective study of 76 patients with surgically treated cervical spine injuries from 1971 to 1980 is presented. The indications for operative treatment, the technical procedures and the preliminary results are analysed. The conclusions are as follows: 1) A rational classification of the cervical spine injuries must precede the decision for operative or conservative management. 2) The intra- and postoperative complications are low with trained staff. 3) Unsatisfactory results from an operation are due to inappropriate indication for an anterior, posterior or combined fusion. 4) A laminectomy should never be done without a fusion, and a decompression of the spinal canal is better done as a rule by an anterior approach. 5) In children an anterior fashion should be avoided in order to prevent deformity from growth arrest of the end plates of the vertebrae. 6) In contrast to the degenerative disc disease the anterior fusion should always be secured by a plate.

Adolescent↗
PubMed1981

Inhibition of experimental stress ulcer formation in rats.

We present an operation model in rats, which according to our opinion prevents duodenogastric reflux effectively. The duodenum is divided distally from the pylorus and a pyloro-jejunostomy performed combined with a Roux-en-Y anastomosis. Rats operated this way and submitted to restraint stress developed significantly less stress lesions than operated control under same conditions. However, operated rats submitted to the operation and offered a 5 mMol/l drinking solution of crude taurocholic acid during 20 days before submitted to stress had significantly more stress lesions than operated animals with tap water before restraint stress.

Animals↗
PubMed1980

[Lysolecithin and stress ulcers in rats].

The effect of lysolecithin on gastric mucosa in rats has been investigated using a new operative model. Ten rats underwent sham-laparotomy. In 4 other groups, each of 10 animals, the rats underwent pyloro-jejunostomy and Roux-en-Y anastomosis. 9 of 10 rats operated upon in this way, and given a solution of lysolecithin to drink before administration of restraint stress, produced stress ulcers. However, only 3 of 10 animals given Ringer-solution produced minor mucosal defects. Lysolecithin not combined with stress had no noteworthy deleterious effect on gastric mucosa either in sham-operated rats or in those with our operation model. Thus, lysolecithin combined with stress in our model performed an important function in the pathogenesis of stress lesions. Lysolecithin is produced in considerable quantities during fat metabolism in the intestine, and may be regurgitated together with duodenal contents into the stomach.

Animals↗
PubMed1980

Experimental microsurgical model in rats preventing duodenogastric reflux. A preliminary report.

For the purpose of studying the significance of the bile and duodenal reflux into the stomach in rats we present an experimental animal model which--in contrast to the procedures reported until now--can exactly be reproduced due to the advantage of microsurgical techniques, thus reducing the operative trauma and accidental results during experimentation. The surgical procedure consists of a pylorojejunostomy with a Roux-en-y loop. This experimental model offers the possibility to discern a great deal of the problems and conditions which may be responsible in the adverse effect of bile and/or duodenal juice on the gastric mucosa.

Animals↗
PubMed1979

Intracranial giant cell arteritis.

A case of giant cell arteritis of intracranial vessels diagnosed by autopsy is described. Giant cell arteritis of the proximal basal brain arteries was exceptionally marked in a man of 60 years. The clinical course, laboratory findings and the pathological alterations of the brain and intracranial blood vessels are described. The case is discussed on the basis of the literature on giant cell arteritis with cerebral symptoms as well as on granulomatous giant cells arteritis of the brain. A separation of these two entities does not seem justified.

Autopsy↗
PubMed1978

Oligodendroglioma with a twenty-two year history. Clinicopathological case report.

Clinico-pathologic report of a patient with an oligodendroglioma who ran a 22-year course characterized by focal epileptic seizures of the Jaksonian type. The EEG remained normal for many years. Since the tumor had not been influenced by therapeutic measures, the histologic picture permitted considering some basic problems of origin, growth, and differentiation of oligodendrogliomas.

Adult↗
PubMedDate not supplied

Effect of mutations at the lariat branch acceptor site on beta-globin pre-mRNA splicing in vitro.

Introns are excised from full-length transcripts (pre-messenger RNAs) of eukaryotic genes in two steps. First, the pre-mRNA is cleaved at the 5' splice site and a branched (lariat) intermediate is formed. Then, cleavage at the 3' splice site and ligation of the two exons leads to the release of the lariat intron. The intron sequence which accepts the 5' end to form the lariat branch is strictly conserved in yeast, but shows more variation in eukaryotes. To investigate the requirements for branch formation in eukaryotes further, we have studied in vitro splicing of a rabbit globin gene intron with mutations of the normal branch-accepting adenosine nucleotide. We conclude that all four nucleotides can serve as branch acceptors, but that A and C are preferred to G and U in lariat formation. Mutation of the normal A to G or U can lead to an A residue one nucleotide upstream of the normal branch site being used instead. Only branches to A or C participate efficiently in the second splicing step.

Adenine Nucleotides↗
PubMedDate not supplied

[The acetabular roof cup in revision arthroplasty of the hip].

The efficiency of the M. E. Müller acetabular roof reinforcement ring is documented on 141 patients with 150 operated hips since 1976 with a minimal clinically and radiologically follow-up of 6 years. The metal backing of the cup prevented cranial migration and protrusion almost completely. After 1982, when a bone bank with frozen femoral heads was established, the loss of bone stock was replaced with allograft, which can be fixed sufficiently with the reinforcement ring. In revision arthroplasty with bone stock of poor quality and quantity the acetabular roof reinforcement ring is a good method to reconstruct the acetabulum.

Acetabulum↗
PubMedDate not supplied

[The internal fixator in nontraumatic indications in spinal surgery].

This series includes 59 consecutive patients, 51 of whom had a minimum follow up of 2 years. The diagnosis was mechanical instability in 39, deformity in 11, and infection or tumor in 9 patients. The overall clinical results of the total group were good or fair in 88% of the patients. Pseudarthrosis occurred twice. We had on postoperative infection, one persistent and two reversible neurological complications. We found 13 broken screws and one rod breakage which had no clinical relevance. None of these asymptomatic complications required revision. The internal fixator has a great potential of correction in scoliotic and kyphotic deformities of the spine. It has not been shown to have the same potential in spondylolisthesis. A combined anterior and posterior stabilisation is needed in severe spondylolisthesis. We have found the internal fixator to provide satisfactory stability to allow fusion and good clinical results with a low rate of relevant complications.

Adolescent↗
PubMedDate not supplied

[The value of diskography in disk-related pain syndrome of the cervical spine for evaluation of indications for spondylodesis].

In this study the postoperative results of patients with cervical spondylodesis for "discogenic pain syndrome" were evaluated. The diagnosis "discogenic pain syndrome" as well as the pathologic segments were confirmed by cervical discography. However interpretation of the discogram as "positive" was only considered reliable when typical pain provocation through discography correlated with pathologic disc pattern ("functional test"). 38 cervical segments have been found to fulfill these criteria and were fused in 29 operative procedures (21 unisegmental, 7 bisegmental, one trisegmental). The patients were evaluated postoperative for change of symptoms, pain character and intensity, neurological deficits, working and sporting disability and mobility of cervical spine. According to the criteria of Simmons and Segil 73% of the patients showed a good to excellent result. A fair result was found in 23.2% and an unsatisfactory result was seen in 3.8%. In the literature a good to excellent outcome is seen in 30 to 46% in similar patients groups after cervical fusion without preoperative assessment by discography.

Brachial Plexus Neuritis↗