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Biomedical subjects

M David

Publications and source records attributed to M David.

At least 667 records · Page 37Linked to original sources
PubMed1979

RNA ligase reaction products in plasmolyzed Escherichia coli cells infected by T4 bacteriophage.

Searching for a physiological role of T4 RNA ligase [polyribonucleotide synthetase (ATP); poly(ribonucleotide):poly(ribonucleotide) ligase (AMP-forming), EC 6.5.1.3] activity, we developed an acellular system of plasmolyzed Escherichia coli cells infected by T4 bacteriophage. Upon incubation of this system with [gamma-32P]ATP, 32P was transferred into a large number of polyribonucleotides, mostly up to 300-400 residues long. The bulk of 32P in the product polyribonucleotides was found in 5'-terminal phosphate groups, suggesting that they originated by a phosphorylation reaction catalyzed by the endogenous polynucleotide kinase (EC 2.7.1.78). Indeed, these products were not seen in an acellular system from uninfected cells, and their amount and complexity increased with the progress of infection. Analysis of the 32P-labeled polyribonucleotide products by gel electrophoresis, either before or after digestion with alkaline phosphatase (EC 3.1.3.1), revealed that a small fraction of the 32P resided in phosphodiester bonds of several tRNA-sized chains. This specific 32P transfer from [gamma-32P]ATP into phosphodiester bonds was apparently catalyzed by successive polynucleotide kinase and RNA ligase reactions. The possible relationship of the 32P transfer to RNA ligase was investigated next by using a system from cells infected with T4 am M69 (an amber mutant deficient in RNA ligase). Transfer of 32P from [gamma-32P]ATP into phosphodiester bonds was not detected in the am M69 system. However, addition of purified RNA ligase to the am M69 system restored the specific 32P transfer. A system from cells infected with T4 psu-b delta 33 (a deletion mutant lacking the entire tRNA region) sustained the specific 32P transfer into tRNA-sized products, indicating that they were not derived from transcripts of T4 tRNA genes. These data may reflect a role of RNA ligase in posttranscriptional conversion of presumably host polyribonucleotides into novel tRNA species during T4 infection.

Adenosine Triphosphate↗
PubMed1979

Widely disseminated cutaneous candidosis in adults.

Of 9 adults, 5 males, 4 females, with wide dissemination of Candida albicans skin lesions, the eruption started in the groin, from which it spread to other areas in most cases. In 5 cases the disseminated lesions were papulo-pustular; the rest were erythematous-squamous. Hyphae and yeast cells of C. albicans were found on direct microscopy. Diabetes was present in 5 patients, lymphoma in 1, and bullous pemphigoid in another. Onychia and paronychia were found in 7 patients, intertriginous lesions of the fingers in 4 and oral thrush in 2. Intradermal skin tests were negative. The percentage and absolute numbers of T-lymphocytes were normal in 6 of 7 patients, whereas their functional activity was imparied in 4 of 6 patients, as evidenced by the negative Graft-versus host reaction. The role of concurrent disease in the pathogenesis of the candidosis is discussed.

Aged↗
PubMed1979

[Oculocraniosomatic neuromuscular disease].

A child with a myopathy that started in the pelvic girdle, non-obstructive cardiomyopathy and retinitis pigmentosa is described. There was a progressive neurological deterioration with external ophthalmoplegia and ptosis. The clinical course could be predicted from the appearance of the muscle biopsy.

Adolescent↗
PubMed1979

Two siblings with epidermodysplasia verruciformis with large clear cells in the epidermis: electron microscope and immunological findings.

In two Arab brothers presenting the characteristic clinical picture of epidermodysplasia verruciformis (EV), histological examination revealed large clear cells in the granular layer and uppermost part of the prickle cell layer of the epidermis. The report of this histological picture in two cases by other authors in the past had aroused considerable discussion as to the true diagnosis. The finding of large clear cells in our two confirmed cases of EV supports the opinion that this does not necessarily contradict the diagnosis of EV. Electron microscope investigation revealed groups of particles in the nuclei of a few keratinocytes in the granular layer which were compatible with papova virus particles. The changes seen in the clear cells support the theory of the viral etiology of EV. Ehe immunological studies showed intact humoral immunity but impaired cellular immunity.

Adolescent↗
PubMed1978

[Septo-optic dysplasia with antidiuretic hormone deficiency and central adrenocortical insufficiency. Three cases report in infants (author's transl)].

Three cases of septo-optic dysplasia are related in infants. A neurogenic diabetes insipidus and an central adrenocortical insufficiency is proved. An growth hormone deficiency is founded in one case. The other anterior pituitary functions are normal. The pneumo-encephalography with congenital absence of septum lucidum and the ophtalmologic anomalies are typical. The treatment is envisaged. In one case an autopsy sustains the radiologic aspect.

Adrenal Insufficiency↗
PubMed1978

[New radiological aspects of tuberose sclerosis (author's transl)].

Amongst the various lesions of tuberose sclerosis, involvement of the kidneys is of particular importance and has special significance in determining the prognosis. Radiological investigations are important for diagnosing the presence and extent of these lesions, for observing their progress and for deciding the appropriate time for treatment. It is difficult to determine whether the tumours are benign or malignant. The value of renal angiography with electronic harmonisation is stressed.

Adult↗