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Biomedical subjects

M Viola

Publications and source records attributed to M Viola.

At least 19 recordsLinked to original sources
PubMed1992

Relational typology in groups.

The aim of this work is to verify, starting from Foulkes' group-analytic perspective, the existence of a link between individual, family and group relational modality on one side, and the many group techniques on the other. This link is well outlined and defined: it is the need to harmonize, to integrate the different parts of the individual, the family, the group. The satisfaction of this need leads to well-being; its dissatisfaction leads to disorders and to the consequent relational modality. In particular, the lack or the reduction of the integrative and associative capacity leads to psychosis, while the disharmony of the different psychical functions leads to neurosis, and the body disharmony leads to psychosomatic disorders. Following Foulkes' group-analytic perspective, the author works out a new definition of man. Man is the final function of all the body functions.

Classification↗
PubMed1991

Molecular cloning of the gene encoding the bovine brain ribonuclease and its expression in different regions of the brain.

In this paper we report the molecular cloning of the gene encoding the bovine brain ribonuclease. The nucleotide sequence determined in this work shows a high degree of identity to the homologous gene encoding the bovine pancreatic ribonuclease. Processing of the primary transcripts of these genes also follows a similar pathway, splicing of the unique intron in the 5' untranslated region occurs at corresponding positions. Expression of the bovine brain ribonuclease gene can be detected both at the transcriptional and translational levels in all the regions of the brain examined.

Amino Acid Sequence↗
PubMed1991

c-src structure in human cancers with elevated pp60c-src activity.

We used RNAase protection and restriction fragment length polymorphism assays to detect activating mutations of c-src in a spectrum of human tumours. No mutations were detected at codons 98, 381, 444, and 530. We conclude that mutational activation is not the mechanism of enhancement of pp60c-src-specific kinase activity found in a number of human cancer types.

Base Sequence↗
PubMed1990

Effect of low-dose lead acetate exposure on the metabolism of nucleic acids and lipids in cerebellum and hippocampus of rat during postnatal development.

Postnatal exposure (from the second day after birth to 30 days) of rat pups to low levels of lead acetate (50 mg/kg body weight/day), administered by gastric intubation, yielded a maximum blood level of 76.1 micrograms/100 ml, at day 15 of age. Cerebellar and hippocampal lead contents were 8.67 micrograms/100 mg and 11.7 micrograms/100 mg, respectively, at day 30 of age. This lead exposure has been shown to elicit little change in some biochemical parameters in cerebellum and hippocampus. At the three ages investigated (5, 15, and 30 days after birth) there were no alterations of body weight; brain, cerebellum, and hippocampus wet weight; and DNA, RNA, protein and phospholipid content, either in total tissue or in mitochondria. A similar invariance following lead exposure was observed in mitochondrial succinate dehydrogenase and cytochrome oxidase activities. After intraperitoneal administration, the incorporation of [methyl-14C]thymidine into DNA and [5,6-3H]uridine into RNA of cerebellum and hippocampus showed a significant decrease only at day 5, reaching the control value at 15 and 30 days of age. After intraperitoneal injection, [2-3H]glycerol incorporation into total lipids and phospholipids of cerebellum and hippocampus also showed no significant changes in Pb-treated pups compared to controls at all three postnatal ages. We concluded that subclinical lead administration exerts its effect by slowing cell proliferation in the very early growth phase of the brain. It is likely that a metabolic compensative response to subtoxic effect of lead acetate may be brought about in cerebellum and hippocampus during critical phases of nervous system development between days 15 and 30.

Animals↗
PubMed1990

Precise, easy measurement of glass pipet tips for microinjection or electrophysiology.

We describe a simple procedure to measure precisely the tip diameter of glass micropipets. This procedure can improve the precision of microinjection and some electrophysiological measurements due to their extreme sensitivity to the pipet's exact geometric dimensions. The technique is nondestructive and readily carried out as a brief, extra step in these applications. Digital measurements of the threshold pressures for gas bubbling from (gas filled) pipets submerged in methanol were used to calculate the corresponding inner tip diameters using the LaPlace equation. Direct measurements of the inner tip diameters (from 0.2-5.0 mu) using scanning electron microscopy confirmed the validity of this indirect, simple procedure.

Electrophysiology↗
PubMed1989

[Our experience on the surgery of liver tumors].

Personal experience of liver surgery for benign and malignant pathology is reported. The type of operation and results obtained in relation to mortality and possible intra- and postoperative complications are considered. The extraparenchymal and transparenchymal techniques are both considered valid but in approaching the vascular structures the former is preferred because it permits preliminary vascular monitoring. The results obtained are similar to those of other series reported in the literature.

Hepatectomy↗
PubMed1989

Intracellular transport and neuronal activation of phospholipid and glycoprotein synthesis during axonal regeneration of cranio-spinal nerves.

In the present work, the hypothesis that the increased rapid intracellular transport of newly-synthesized material along the axons of a regenerating system is sustained by an alteration of the transport of proteolipid complexes through subcellular compartments of a neuronal cell body was tested by a biochemical methodology. The motoneurons of spinal cord ventral horn, 4 wk after unilateral lesion (crush) of cervico-thoracic nerves of the rabbit at the level of brachial plexus, were chosen as the model system of regeneration. A time-staggered procedure of in vivo and in vitro double labeling with metabolic precursors, such as [3H]-choline, [14C]-choline, [3H]-fucose, and [14C]-fucose, was used. Subcellular fractions (RER, SER, Golgi apparatus, and plasma membranes) of ventral horn tissue, taken from spinal cord hemisections (regenerating and contralateral side), were further isolated. Twenty-eight days after axotomy, we did not observe any change of intracellular transport kinetics (14C/3H ratio) of newly-synthesized choline-phospholipids and glycoproteins in regenerating motoneurons compared to controls. However, associated with regenerating phenomenon in Golgi apparatus, we observed an increase of labeled choline-phospholipid and glycoprotein material that could contribute to the increased fast axonal transport and delivery of membrane proteolipid complexes to plasma membrane and axonal compartments. The increase of glycoprotein labeling was more pronounced in the SER portion (vesicles and elements of smooth membranes). This result is in favor of the hypothesis that membrane-bound proteins are transported from the Golgi to the axon through the perikaryal SER.

Animals↗
PubMed1989

Region-selective decline of in vivo lipid synthesis in the aged rat visual system.

[14C]palmitate and [3H]choline were injected intravitreally and, at the same time, intraventricularly in Wistar male rats at 4, 10, and 24 mo of age. The precursor incorporation into lipids of the retina, optic nerve tract, superior colliculus, and lateral geniculate body was followed for 2 h. The specific radioactivity of precursors pool (choline, phosphorylcholine, and free fatty acids) showed a marked decrease in optic nerve tract and lateral geniculate body of aged rats, whereas in retinal tissue and superior colliculus no changes were observed as a function of age. In rats of the three age groups, whole retina and superior colliculus showed neither changes of choline incorporation into phosphatidylcholine and sphingomyelin nor alteration of palmitate incorporation into diacylglycerols, triacylglycerols, and major phospholipid classes as a function of age. In sharp contrast, the optic nerve tract and, to a lesser extent, the lateral geniculate body exhibited a significant age-related decline of either the incorporation of both precursors into all lipid classes or the specific radioactivities of endogenous precursor pools. We concluded that the visual pathway structures are metabolically affected in a different manner by aging. Particularly, the ability of the retina and superior colliculus to metabolize lipids appeared to be age invariant. The marked decline of lipid biosynthesis with age, for some visual structures, is consistent with the trend generally observed in metabolic turnover and function of other CNS regions.

Aging↗
PubMed1988

Age-related changes of RNA and lipid synthesis in vitro by retina and optic nerve of the rat.

We examined the effects of age on RNA and lipid formation by whole retina and optic nerve in vitro. Male Wistar rats, aged 4, 12, and 24 mo, were used. From the results obtained the following conclusions may be drawn: 1. In assaying the lipid biosynthesis during aging, a striking difference between the retina and optic nerve clearly emerged; 2. In isolated retina, [3H]uridine incorporation into RNA was relatively constant at the three ages, whereas both [14C]palmitate and [3H]choline incorporation into lipids showed a substantial increase in rats at 24 mo of age compared with those at 4 mo; 3. In contrast, in the optic nerve of the oldest rats, compared with the youngest, a significant decrease of [14C]acetate and [14C]palmitate incorporation into acylglycerols, cerebrosides, and phospholipids was found. Each fatty acid precursor label was incorporated to a proportion that reflected the typical acyl group composition of individual lipids; 4. Following labeling of the optic nerve with [3H]choline, the specific radioactivity of choline-containing phospholipids was drastically decreased with increasing rat age; and 5. The incorporation of [2-3H]glycerol into optic nerve diacylglycerols, PtdEtn, and PtdIns declined with age, whereas no significant change took place in the incorporation into PtdCho. The results strongly support the concept that RNA metabolism of rat retina (most likely photoreceptor cell layer) is not altered during aging; on the contrary, phospholipid synthesis is stimulated in comparison with that of the optic nerve, for which a serious impairment was concomitantly observed. The physiological significance of these responses, and the mechanism by which retinal tissue is spared from the general age derangement of the nervous system, remain to be defined.

Aging↗
PubMed1985

Synthesis of myelin proteins and ultrastructural investigations in regenerating rat sciatic nerve.

Myelin protein synthesis, as well as ultrastructural and morphometric changes in regenerating peripheral nerve, was studied. Sciatic nerves of rats were crushed unilaterally; sham-operated nerves of the contralateral side served as controls. For the in vivo experiments, rats were killed at selected periods after the nerves were crushed (30, 60, 90, and 120 days); seven days prior to killing, the animals were injected intravenously with L-[4,5-3H]leucine. For the in vitro experiments, proximal and distal segments of sciatic nerve and equivalent sham-operated nerves were labeled with 3H-amino acid mixture 90 days after axotomy. Purified myelin was isolated from nerve segments; specific radioactivity and gel electrophoretic patterns of proteins were analyzed. Cross-sectional electron microscope (EM) preparations of proximal, distal, and contralateral segments of nerves also were examined. Results showed that the incorporation of labeled amino acids into total myelin proteins was enhanced significantly in the distal segment of sciatic nerves at all of the periods of regeneration studied. The yield of myelin protein per mm distal nerve segment increased as regeneration proceeded. The remyelination of fibers early after nerve crush was weak, whereas it gradually attained the normal range 90-120 days after axotomy. Morphometric analysis of myelin sheath thickness of regenerating axons was consistent with the data obtained for myelin protein synthesis.

Animals↗
PubMed1985

Remodeling and sorting process of ethanolamine and choline glycerophospholipids during their axonal transport in the rabbit optic pathway.

The existence of a mechanism by which the ester- and ether-linked aliphatic chains of the major phospholipids are retailored during their axonal transport and sorted to specific membrane systems along the optic nerve and tract was investigated. A mixture of [1-14C]hexadecanol and [3H]arachidonic acid was injected into the vitreous body of albino rabbits. At 24 h and 8 days later, the distribution (as measured by the 3H/14C ratio) and the positioning (as monitored by hydrolytic procedures) of radioactivity in the various phospholipid classes of retina, purified axons, and myelin of the optic nerve and tract were determined. At the two intervals after labeling, the 3H/14C ratios of each diradyl type of phosphatidylethanolamine and phosphatidylcholine were (a) substantially unchanged all along the axons within the optic nerve and tract and (b) markedly modified in comparison with those found in the retina and axons for molecular species selectively restricted to myelin sheath. Evidence is thus available that intraxonally moving ethanolamine and choline glycerophospholipids, among others, are added to axonal membranes most likely without extensive modifications. In contrast, they are transferred into myelin after retailoring. Through these two processes, the sorting and targeting of newly synthesized phospholipids to their correct membrane domains, such as axoplasmic organelles, axolemma, or periaxonal myelin, could be controlled.

Animals↗
PubMedDate not supplied

Inhibition of growth factor-induced differentiation of PC12 cells by microinjection of antibody to ras p21.

The protein products (p21) of the ras cellular proto-oncogenes are thought to transduce membrane signals necessary for the induction of cell division. However, there is uncertainty as to the precise role of ras p21 in mediating ligand-membrane receptor signals leading to cell differentiation. Treatment of rat phaeochromocytoma cells (PC12) with nerve growth factor (NGF) results in the induction of a number of phenotypic characteristics of sympathetic neurones, including cessation of cell division and outgrowth of neuronal processes (neurites). Here we report that microinjection of antibody to ras p21 into PC12 cells inhibited neurite formation and resulted in temporary regression of partially extended neurites, an effect which was observed up to 36 h after initiation of NGF treatment. Neurite formation induced by cyclic AMP was unaffected by injection of anti-p21 antibody. These results indicate that p21 is involved in the initiation phase of NGF-induced neurite formation in PC12 cells and has a role in hormone-mediated cellular responses distinct from cell proliferation.

Animals↗