Biomedical subjects

M Bayer

Publications and source records attributed to M Bayer.

112 records · Page 7Linked to original sources

PubMedDate not supplied

Pseudohypoparathyroidism type IA and II with severe neuropsychic manifestations.

Pseudohypoparathyroidism (PHP) is characterized by unresponsiveness of target tissues to the biological actions of the parathyroid hormone (PTH), with resulting hypocalcemia and hyperphosphatemia, despite the elevated serum levels of PTH. PHP is divided into types Ia, b, c and II, depending on the presence of Albright's hereditary osteodystrophy (AHO), defective urinary excretion of phosphate (U-P) and response in urinary excretion of cyclic adenosine monophosphate (U-cAMP) after the administration of exogenous PTH. Patients with PHP might exhibit various manifestations of neuropsychic disturbances. We present two boys, aged 14 and 16 years, both with paresthesia, anxiety and epilepsy; the former patient also suffered from mild mental retardation. In both patients, hypocalcemia and hyperphosphatemia together with increased serum levels of PTH suggested the diagnosis of PHP. After administration of exogenous PTH (Ellsworth-Howard test), there was a drop in U-P in both patients, while U-cAMP was decreased in the first patient and increased in the second one, thus confirming the diagnoses of PHP Ia and II, respectively. Neuropsychic disturbances and epilepsy resolved completely in both patients after treatment with calcium and dihydrotachysterol. Evaluation of calcemia and phosphatemia should be mandatory in all patients with neuropsychic disorders. Ellsworth-Howard test remains a useful tool in the differential diagnosis of PHP.

Adolescent↗

PubMedDate not supplied

Inhibition of histone-mediated gene transfer in eucaryotic cells by anti-histone IgG.

In our laboratory, the gene transfer efficiency of some lipofection reagents (lipofectine, lipofectamine, DOTAP and Dosper) and histones H3 and H4 was compared to that of DEAE-Dextran (64). The histones H3 and H4 were found to have the highest transfection efficiency of all the agents tested. In the present study we have analyzed other parameters important for gene delivery by the histones H3 and H4. We transferred the HIV-1 tat gene to Jurkat cells and measured the transactivation of HIV-1-LTR by the transactivator protein, expressed in Jurkat cells. The expression of CAT as a reporter gene hybridized to LTR was a direct measure of transactivation potential. In order to investigate whether the transfection was only due to the positive ionic character of the histones H3 and H4 we tested other histones (H1 and H2A) and polylysine in our system. Under our experimental conditions, neither polylysine, nor the histones H1 and H2A were able to promote gene transfer in Jurkat cells. The inability of these reagents to promote gene transfer was not dependent on DNA condensation; in EMSA (Electrophoretic Mobility Shift Assay) all these reagents exhibited a strong retardation of DNA. In the presence of anti-histone-IgG the transfection potential of histones H3 and H4 was diminished in a concentration - dependent manner. To investigate whether the histone antibodies inhibited the condensation of DNA by histones we carried out gel retardation assays (EMSA) in the absence and in the presence of histone antibodies. Anti-histone-IgG had no effect on the retardation of histone-DNA complexes; on the contrary, retardation was increased. This observation has led us to postulate two models for the possible mechanism by which the histones H3 and H4 catalyze gene transfer in eucaryotic cells.

Chloramphenicol O-Acetyltransferase↗

PubMedDate not supplied

[Chronic polyarthritis and carpal tunnel syndrome. Results of follow-up].

Between July 1974 and December 1989, carpal tunnel-syndromes (CTS) were operated on in 903 hands of 746 patients. 147 of these patients (191 hands) were suffering from chronic inflammatory joint diseases. In 11 patients CTS was the first sign of rheumatoid arthritis (R.A.). The hands showed intraoperatively in 44.8% (n = 86/191) an extensive tenosynovitis with an aggressive infiltration. In 19% (n = 36/191), we had to extend the obligate tenosynovectomy on the flexor tendon parts of the fingers and ligaments (28 hands). 21 articulosynovectomies on the wrist or finger joints were performed. In 6 hands (8.0%) tendon ruptures were repaired. A questionnaire was completed for 107 of 147 patients (72.8%) (with 145 operated hands). Clinical (77 hands) and electromyographical examinations (49 hands) were performed an average of 5.1 (0.7-15) years postoperatively. 20 patients (13.6%) died, 20 could not be traced. In 86% (n = 125/145) of the patients we achieved relief of pain and a marked reduction of neurological deficits. 96.3% of the patients were content. The improvement of function of the hand after surgical intervention is of a great benefit for the patient with R. A. The overall risks of the procedure are low (complications 14%; no recidivism). Therefore, we recommend surgery in early stages after a confirmed diagnosis or a reasonable suspicion.

Adult↗

PubMedDate not supplied

A case of transient hyperphosphatasaemia following vitamin D-deficient rickets.

A seven-month-old boy with a diagnosis of vitamin-D deficiency rickets is presented. After treatment with vitamin-D, biochemical and radiological improvement was noted. At 14-months of age the plasma akaline phosphatase activity valve was found to be elevated even though rickets was not present. A diagnosis of hyperphosphatasemia was established. Although rare in infancy, transient hyperphospha tasemia may occur following vitamin-D deficient rickets. This possibility should be considered when evaluating laboratory results in such cases.

Alkaline Phosphatase↗