Biomedical subjects
Publications and source records attributed to R Cuppini.
The effect of Berus viper's venom on the osmotic globular resistance of human blood, incubated for a period of 2 hours at 20 degrees C with amounts of venom in the range of 200 to 400 gamma/ml of blood, has been studied. The hemolytic effect occurs to a greater extent at NaCl concentrations higher than 0,60%.
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The regeneration of the sciatic nerve fibres was studied in both normal and vitamin E-deficient rats at 30 and 60 days after crush. The vitamin E is involved in one of the most important mechanisms of protection against peroxidation of plasma membrane lipids; the plasma membrane plays certainly a role in nerve regeneration. Both the diameter and the total number of myelinated nerve fibres was calculated at different times. The number of myelinated fibres in the undenervated deficient animals was lower than that found in the undenervated normals animals. Following the nerve crush, in normal animals after two months the number of myelinated fibres exceeded the number found in undenervated normal animals, whereas in the deficient rat nerves it was significantly lower than in the corresponding controls and moreover it did not even reach the number found in the nerves of undenervated deficient rats. Finally, the caliber distribution of myelinated fibres in undenervated and denervated deficient rats shows a relative percent increase in the number of greatest axons and a decrease in smaller axons. This result confirm the vitamin E to be an important factor of the normal process of nerve regeneration.
Unmyelinated axons of normal and regenerated sciatic nerve were counted in controls and vitamin E-deficient rats. No significant change in the number of unmyelinated axons of uninjured nerve was found in the vitamin E deficiency in comparison to controls (12961 +/- 1591 and 12450 +/- 1290, respectively, mean +/- SEM). In regenerated nerve of control rats the number of unmyelinated axons was higher than in uninjured nerve (16971 +/- 1854 and 20786 +/- 1574 at 1 and 2 months after crush, respectively). In vitamin E-deficient rats the increase in number of unmyelinated axons was greater than in corresponding controls (21880 +/- 662) at 1 month after lesion, but the number returned to value found in uninjured nerve at 2 months after lesion (12536 +/- 659). These results suggest that sprouting at lesion may be enhanced but some regenerated axons does not survive at long term in vitamin E-deficiency.
Proanthocyanidin-A2, a catechic dimer extracted from the bark of Aesculus hippocastanum L., was tested on peripheral nerve regeneration. Reinnervation of EDL and soleus muscles following traumatic nerve damage was investigated in rats by using "in vivo" tension recording technique. Muscle contraction force (twitch and tetanus), the number of motor units and the time course of twitch (time to peak and half relaxation time), were observed. The results obtained do not show that the time course of EDL and soleus muscles reinnervation is different in Proanthocyanidin-A2-treated rats in comparison to control animals. On the contrary, results point out an increase in EDL and soleus muscle mass, both in denervated and in undenervated treated rats compared to corresponding controls. Moreover, consistently with this finding, an increase in their contraction force was found. These data show that Proanthocyanidin-A2 exerts a trophic effect on muscle.
Sprouting induction by a peripheral degenerating nerve has been evaluated in normal and vitamin E-deficient rats. A piece of sural nerve was grafted close to the peroneal nerve of the same animal: at one and two months after grafting thin unmyelinated axons were visible in the graft and they were sometimes functionally active; when nerve explant was frozen before grafting, sprouting induction did not take place either in controls or in vitamin E-deficient animals. No difference was noted in sprouting induction between the two groups, while degeneration showed a different time course. Some hypotheses of possible stimuli of sprouting induction are discussed.