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Biomedical subjects

C Di Benedetta

Publications and source records attributed to C Di Benedetta.

At least 19 recordsLinked to original sources
PubMed1989

Identification and cDNA cloning of a new member of the L2/HNK-1 family of neural surface glycoproteins.

Rabbit antibodies raised against a 135- to 140-kD glycoprotein isolated from the culture medium of mouse forebrain explants were used for the identification and cloning of a complex of mouse neural cell surface glycoproteins. The antibodies recognized a 135-kD surface protein which shared the L2/HNK-1 epitope with several neural cell adhesion molecules. Three homologous complementary deoxyribonucleic acid (cDNA) clones were isolated from a mouse brain cDNA library prepared in the expression vector lambda gt11, one of which was sequenced and found to lack sequence homologies with known proteins. In Northern blots, this clone hybridized with a single 6.3 kb messenger ribonucleic acid (mRNA). In immunoblots of mouse brain extracts, antibodies raised in rabbits against the fusion protein encoded by it stained two glycoproteins of 135 and 90 kD, which we designated F3.135 and F3.90. In the developing mouse cerebellum, F3 antigenic sites were found predominantly on parallel fibers and on postmitotic neurons. In fetal brain cell cultures, F3 antigen was detected at the surface of cells with neuronal morphology, but the antibodies also stained some non-neuronal cells in a pattern characteristic of matrix components. Because all proteins carrying the L2/HNK-1 epitope identified so far have a role in cell adhesion, it can be anticipated that the F3 surface proteins also are involved in cell-interaction phenomena.

Animals↗
PubMed1989

Developing rat cerebellum--III. Effects of abnormal thyroid states and undernutrition on gangliosides.

Alteration of rat postnatal cerebellar development produced by undernutrition, thyroxine treatment and thyroid deficiency also involves ganglioside deposition. The distribution of the different ganglioside types is apparently unaffected but quantitative alterations are present that reflect the reduction of cell number and cell process surface in the adult, and either acceleration or slowing down or reduction of cell formation and maturation occurring during cerebellar development in the three experimental situations.

Aging↗
PubMed1983

[Temporal decay of the effect of a single vagal stimulation on cardiac rhythm in the rabbit].

The negative chronotropic effect of a single stimulus randomly delivered through right, left or both vagi respectively, within the cardiac cycle was studied in anaesthetized rabbits. The effect was analyzed on the P-P cycles subsequent the stimulus application, calculating percentagewise the delay observed in definite time-lapses, equalized to two pre-stimulus cycles. The results indicate that the efficacy of the negative chronotropic effect of vagal stimulation shows the least delay the closer the stimulus to the wave, while the delay is higher when the stimulus is delivered within the central portion of the cycle.

Animals↗
PubMed1983

[Integration of the effects of a single stimulus applied to the vagus nerve on the right and the left, in the rabbit heart].

It was reported by the literature that a train stimulation, simultaneously delivered on the two vagi, resulted in a decrement of the negative chronotropic effect, when it was compared to the sum of the effects obtained by the stimulation of the two nerves, separately. Our data indicate that the size of the chronotropic effect obtained by the simultaneous application on the two vagi of a single supraliminar stimulus, randomly applied within the P-P cycle, in rabbits, can be equal, higher or lower than the sum of the same stimulation separately delivered to the two nerves. The results could depend upon the different amount of acetylcholine released during stimulation. The hypothesis is put forward that different patterns of the neuro-cardiac junction regulation might be activated according to the quantity of released neuromediator.

Animals↗
PubMed1983

Time-dependency of the response to a single vagal stimulus in the rabbit heart.

The time-dependency of vagal effects on P-P cycle was studied in rabbits, chosen because of high heart rate, in order to verify the occurrence of this phenomenon already described for animals with lower heart rate. In five rabbits with different resting cardiac cycles, vagal stimuli were delivered randomly. The results indicate that for heart rates higher than 120 beats/min no occurrence of Brown and Eccles' time-dependency was observed. It is evident, however, the different responsiveness of the pacemaker to vagal stimuli delivered at different times of the cardiac cycle. In particular a stimulus given beyond 40-50% of the cardiac cycle does not affect the same but the next cycle.

Acidosis↗
PubMed1983

A novel soluble brain-specific protein (Sy-1). Identification and partial characterization.

A novel brain-specific antigen, called Sy-1, has been identified in whole rat brain hypotonic extracts by means of an antiserum produced in rabbits against the synaptosomal cytosol. Sy-1 is an acidic protein (pI 4.7) present exclusively in a soluble form and it does not carry any sugar moiety. Sy-1 is found only in rat brain and, in a partially identical form, in mouse brain. In rat brain the antigen is more concentrated in the brainstem than in the forebrain and cerebellum. On the basis of immunological, physico-chemical and biological criteria Sy-1 differs from other, already described, brain-specific proteins.

Animals↗
PubMed1980

[Individual characteristics and biological rhythms. I. Morning and evening subject typing based on cluster analysis].

The Horne and Hostberg questionnaire to differentiate "morning" and "evening" types was adopted to study the morningness-eveningness in I44 medical students. Furthermore the reliability of the proposed typology was assessed by using the cluster analysis, which partially confirmed the categories of Horne and Ostberg, since the clusters were characterized by the presence of subjects belonging to different types. No difference by sex was observed by either method. By means of the cluster analysis it was possible to identify 20% of evening and 40% of morning types.

Adult↗
PubMed1980

[Individual characteristics and biological rhythms. III. Utilization of a modified questionnaire to type morning and evening students].

A questionnaire modified in regard to that previously suggested by Horne and Ostberg has been utilized to distinguish the "morning" from the "evening" types. In 144 medical students it was found that almost 22% were evening type and 53% were morning type. By means of the new questionnaire there was an increment, percentagewise, of both groups from the 62% to 75%, indicating the usefulness of the method. The study of biological as well as psychological parameters should be pursued in order to control the validity of these results.

Adult↗
PubMed1980

[Analysis of proteins and glycoproteins from adult bovine cerebellum. II. Quantitative separation by Con A Sepharose chromatography].

Soluble and insoluble glycoproteins from adult bovine cerebellum have been separated by affinity chromatography on ConA-Sepharose and analyzed by polyacrylamide gel electrophoresis I2% in presence of SDS. Soluble fraction represents 26% of total proteins. Within soluble and insoluble fractions 4.5% of proteins binds to ConA. Electropherograms of the soluble and insoluble fractions as well as of the proteins not absorbed on ConA-Sepharose, display a very complex pattern. Soluble fractions present many sharp bands in the region of molecular weight above 100 k. Heterogeneity is lesser in ConA-binding proteins. The contamination by Concanavalin A is considered. At present no definite conclusions can be drawn regarding the similarities existing between s.c. soluble and membrane-bound cerebral glycoproteins.

Animals↗
PubMed1979

[Analysis of cerebellar proteins and glycoproteins in adult cattle. I. Con A positive glycoproteins].

The cerebellar glycoproteins of bovine have been separated by affinity chromatography on Con A-Sepharose and analyzed by poliacrylamide gel electrophoresis. Some soluble Con A binding glycoproteins are common to the insoluble (membrane bound) glycoproteins suggesting a relationship between the two classes of molecules. The data support the hypothesis that some of the soluble glycoproteins can be considered precursors of the insoluble.

Animals↗