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Biomedical subjects

A Martinotti

Publications and source records attributed to A Martinotti.

At least 19 recordsLinked to original sources

Localization of growth arrest-specific genes on mouse chromosomes 1, 7, 8, 11, 13, and 16.

Growth arrest in NIH3T3 cells is associated with increased expression of a variety of mRNAs, several of which have been isolated as cDNA clones. Six of these growth arrest-specific (Gas) genes were mapped by following the inheritance of DNA restriction fragment length variants (RFLVs) associated with them in panels of recombinant inbred (RI) strains of mice and in the progeny of backcrosses both between laboratory mouse strains and between a laboratory strain and Mus spretus. The six genes are unlinked. Gas-1 maps to Chromosome (Chr) 13, Gas-2 to Chr 7, Gas-3 to Chr 11, Gas-4 to Chr 16, Gas-6 to Chr 8, and Gas-10 to Chr 1.

3T3 Cells

Isolation and mapping to 17p12-13 of the human homologous of the murine growth arrest specific Gas-3 gene.

A family of growth arrest specific (Gas) genes was operationally defined on the basis of the strategy utilized to isolate them e.g. differential expression in quiescent and growing cells. Our interest in the Gas-3 gene was prompted by our previously reported localization of the gene on the mouse chromosome 11.44 +/- 1.9 cM proximal to the Trp53 locus and by the finding, by others, that it codes for a myelin protein and that a point mutation in its fourth putative transmembrane region is associated with the trembler mutation. We have isolated the human homologous of the mouse Gas-3 gene and utilized the cloned sequences as a probe to localize the gene on human chromosomes both by analysis of human-rodent somatic cell hybrids and in situ hybridization of human metaphases. We have now localized the human Gas-3 gene on chromosome 17p12-13. Its possible role in both the development of neoplasia in neurofibromatosis patients and in the myelin degenerative disease as the Charcot-Marie-Tooth is discussed.

Amino Acid Sequence

Subcellular structure of the atrial myocardium of children in cases of atrial septal defect.

In order to study the initial development of myocardial ultrastructural changes owing to right atrium volume overload, myocytes have been studied in specimens taken from the right atrial wall and auricle of four children aged 1 to 6 years with ostium secundum atrial septal defect undergoing cardiac surgery. The younger patients (1 to 4-year-old children) we observed did not show diffuse and significant myocardial ultrastructural damages. The most significant myocardial changes were observed in the 2 older patients (six years old) as we found subcellular signs of myocardial hypertrophy such as an increased number of mitochondria, increased glycogen inclusions, areas of new sarcomerogenesis and nuclei lobulated and variably shaped. Focal degenerative changes, such as rupture of mitochondrial cristae and intercellular fibrosis were also noted. These changes may be considered as the initial features of myocardial hypertrophy because they were not as severe and diffuse as those usually seen in a marked functional failure.

Cardiomegaly

Scanning electron microscopy of stellate cells of mammalian adrenal cortex as revealed by NaOH maceration.

After removal of connective tissues by the NaOH maceration method, adrenal gland stellate cells of monkeys, rats and rabbits were studied by scanning electron microscopy. The stellate cells were situated in the perivascular and interstitial spaces and showed an ovoid cell body with numerous round or flat processes. Through these processes they were in contact with other adjacent stellate cells and thus formed a continuous cellular net around capillaries and parenchymal cells. This net, which probably provides a cellular scaffolding for the gland, may also play additional roles such as capillary contraction and nutrition for adjacent parenchymal cells.

Adrenal Cortex

[Effect of diazepam on mitochondrial respiration].

Our hypothesis that the strong effects of neutropic drugs on nervous system have hidden more widespread effects on all tissues and cells, is collecting evidences in our laboratory. We have essayed in vitro benzodiazepines on liver rat mitochondria. The present work deals with experiments on diazepam: it depresses the respiration coupled to phorphorylation in mitochondria having a good respiratory control; so respiratory control too is depressed. Also P/O ratio is lowered.

Animals

Magnesium plus nifedipine: potentiation of hypotensive effect in preeclampsia?

Two women with preeclampsia treated unsuccessfully with alpha-methyldopa and magnesium sulfate became profoundly hypotensive when oral nifedipine was added. Blood pressure returned to previous levels without changes in fetal vitality. Awareness of this potentiation is important because nifedipine is being used increasingly in the treatment of pregnancy-related hypertension.

Adult

Effect of vincristine on bone marrow cells of patients with multiple myeloma. A cytokinetic study.

The cytokinetic changes induced by Vincristine (VCR) on bone marrow erythroblasts, myeloid cells and neoplastic plasma cells have been studied in four patients with plasma cell malignancies using combined DNA cytofluorometry and in vitro tritiated thymidine cytoautoradiography. The changes observed 9 h after the administration of the drug were in accordance with its S-phase specificity. The magnitude of the stathmokinetic effect was in fact roughly proportional to the proliferative activity of the different cell lines, i.e., marked on the erythroblasts, less evident on the myeloid cells and still lower on the plasma cells. In this last cell population VCR has also blocked or partially impaired the DNA synthesis. Nine days after VCR, the plasma cells were recruited into the proliferative cycle while the regeneration of the hemopoietic cells was already exhausted. Repeated administrations of VCR spaced at about 9 day intervals are more and more effective on the plasma cell population, since the S place specificity of the drug against the recruited plasma cells is potentiated. On the contrary, the regeneration of the hemopoietic cells is protected by this time interval.

Autoradiography