PubMed Health⌕ Search

Biomedical subjects

D Testa

Publications and source records attributed to D Testa.

At least 109 records · Page 6Linked to original sources
PubMed1979

Interaction of a limited set of proteins with different mRNAs and protection of 5'-caps against pyrophosphatase digestion in initiation complexes.

A variety of 5'-3H-methyl-labeled, oxidized viral mRNAs were used as probes for detecting in wheat germ initiation complexes proteins that interact with, and can be cross-linked to, the 5'-cap structure. A limited and reproducible set of specific proteins was obtained with the different mRNAs. The binding of these proteins to the 5'-end of mRNA apparently results in protection against nucleotide pyrophosphatase digestion of the cap even in initiation complexes in which the 5'-end is susceptible to pancreatic RNase digestion. Cross-linked proteins from mammalian initiation complexes comigrated with several of the subunits of similarly treated eIF-3. A model for cap binding protein interaction with mRNA cap during initiation of translation is suggested.

Animals↗
PubMed1979

Initiation of RNA synthesis in vitro by vesicular stomatitis virus. Role of ATP.

The ATP requirement during RNA transcription by the RNA-dependent RNA polymerase associated with purified vesicular stomatitis virus was studied during chain initiation and chain elongation steps. Initiation of transcription in vitro has an apparent Km for ATP of approximately 500 micron, whereas the apparent Km for ATP during chain elongation is almost identical with those for the other three ribonucleoside triphosphates, i.e. 20 to 30 micron. Further analysis of the transcription process demonstrated that the beta-gamma imido analogue of ATP cannot be used for the initiation step. However, it can be incorporated into RNA during chain elongation. These results indicate that a hydrolyzable form of the beta-gamma phosphodiester bond in ATP is required for the initiation process and also support the hypothesis for a single promoter site for the initiation of transcription on the genome of vesicular stomatitis virus.

Adenosine Triphosphate↗
PubMed1977

Two methyltransferase activities in the purified virions of vesicular stomatitis virus.

In addition to an RNA-dependent RNA polymerase, purified vesicular stomatitis virus contains a methyltransferase activity which transfers the methyl group from the methyl donor, S-adenosyl-L-methionine, to two positions in the 5'-terminal capped structure of the nascent mRNA's synthesized in vitro as 7mG-(5)'ppp(5')Apm... In the present study it is shown that two distinct methyltransferase activities are discernible in the purified virus. The in vitro concentrations of the methyl donor specify the number and location of the methyl groups transferred to the capped 5'-termini of VSV mRNA's. Limited concentrations of the methyl donor result in a single methylation of the penultimate base in the 2'-hydroxyl position, that is, G(5')ppp(5')Apm..., whereas saturating concentrations of the methyl donor methylate the blocking guanosine residue at the 7-position, resulting in the dimethylated cap, 7mG(5')ppp(5')Apm... Pulse-chase experiments demonstrate that the monomethylated cap structure is the precursor substrate for the dimethylated cap. In this respect, vesicular stomatitis virus system is quite distinct from the vaccinia and reovirus systems. Virus purified from different host cells including hamster, mouse, and human contain both methyltransferase activities. The mRNA's containing monomethylated capped structures are poor templates for protein synthesis in vitro.

Kinetics↗
PubMedDate not supplied

Cerebral MR findings in tuberous sclerosis.

Cerebral magnetic resonance (MR) and CT findings of two sisters affected by clinically defined tuberous sclerosis are reported. Magnetic resonance showed a greater number of lesions than did CT. In addition, MR depiction of the abnormalities better corresponded to the pathological findings usually described in this disease.

Adult↗
PubMedDate not supplied

Sneddon's syndrome and renal carcinoma. Case report.

A patient with Sneddon's syndrome in association with renal neoplasm is discussed. The association has not been reported before and raises questions concerning the pathogenesis of vascular proliferation in Sneddon's syndrome.

Adult↗
PubMedDate not supplied

Cerebral multiple glio-vascular dysplasias--a case report.

We describe the clinical and neuropathologic features of a patient complaining of increased intracranial pressure lasting over two years. Brain CT showed three cystic lesions in the supratentorial regions. Autopsy disclosed multiple small glio vascular abnormalities, in some instances connected with a cystic cavity. The lesions were scattered throughout the white matter of both cerebral hemispheres and suggested a complex dysplasia.

Biopsy↗
PubMedDate not supplied

[Histological and ultrastructural features of a case of subacute sclerosing panencephalitis (author's transl)].

A case of subacute sclerosing panencephalitis is described from a clinical, histopathological and ultrastructural point of view. The most notable morphologic feature is the presence of a great number of nuclear inclusions inside both neurons and oligodendroglial cells. These inclusions are spread to the whole brain and are decreasing in number from the cerebral cortex towards midbrain. The cerebellum is completely spared. The Authors discuss the problems related to the viral origin of the disease, to the diffusion of the virus inside nervous system and to the myelin degeneration in the light of the recent literature.

Adolescent↗
PubMedDate not supplied

Centronuclear myopathy with unusual mitochondrial abnormalities.

The case of a 34-years-old man is described with a progressive myopathy characterized by limb weakness and atrophy, involvement of facial, masticatory and extraocular muscles. The prominent features of the muscle biopsy were the presence of centrally located nuclei in most fibers. There was also an atrophy and predominance of type I fibers. Both clinical and morphological features were consistent with the diagnosis of centronuclear myopathy. Electron microscopic studies showed the presence of mitochondria with paracrystalline inclusions near the centralized nuclei but not in the subsarcolemmal position. This hitherto unreported feature led the authors to re-evaluate the hypothesis on the pathogenesis and the nosological classification of this myopathy.

Adult↗
PubMedDate not supplied

[Immunological changes in diabetes mellitus. Study of lymphocyte populations].

In view of some data of the literature suggesting that immunological changes could play a role in the pathogensis of diabetes mellitus and of its complications, we carried out a study of the lymphocyte populations of 44 diabetic subjects by means of E, EA, EAC rosettes and membrane immunofluorescence. A quarter of the patients had decreased E rosettes: all of these had long-lasting, insulin-dependent, poorly controlled diabetes. Some of these patients had also increased membrane IgG globulins. In 5 patients with recent onset, insulin-independent diabetes, E rosettes were increased. No significant changes of EA and EAC rosettes were observed. These findings suggest that changes of lymphocyte populations do not play any role in the pathogenesis of diabetes, while these may be the consequence of the metabolic disorder and these may favour the onset of complications of the disease.

Adult↗
PubMedDate not supplied

[Immunity and neoplasms. Behavior of E rosette-forming lymphocytes in patients with malignant neoplasms].

The per cent and absolute figures of E rosette forming lymphocytes have been evaluated in the blood of normal subject and of patients with non-neoplastic diseases and with epithelial and lymphoreticular tumours. The percentage of rosetting lymphocytes was not affected by non-neoplastic diseases, whilst it was by tumours, especially by lymphoreticular ones. However differences were not statistically significant in view of the large dispersion of values. Absolute counts of rosetting lymphocytes displayed lesser variations. These findings are better explained by Schwartz's concept of immunoregulation than by Burnet's theory of immunosurveillance.

Adolescent↗