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Biomedical subjects

A Bassi

Publications and source records attributed to A Bassi.

At least 91 records · Page 5Linked to original sources
PubMed1988

Increased proteolytic activity of erythrocyte membrane in spur cell anaemia.

In a case of 'spur cell anaemia' (SCA) a reduced esterified/free cholesterol ratio was found in plasma, in LDL and HDL fractions and an increased cholesterol/phospholipid (C/PL) molar ratio in erythrocyte membrane. Cation transport was normal with the exception of Li-Na counter-transport was decreased. An increased intrinsic membrane proteolytic activity (IMPA) was demonstrated by the generalized reduction or, sometimes, disappearance of protein bands on SDS-PAGE in patient ghosts when the proteolysis was allowed. This characteristic was found to be transferable to normal cells by incubation in SCA-plasma; moreover membrane C/PL molar ratio was augmented after incubation. Normal plasma was not able to normalize IMPA of SCA cells 'in vitro', even if it induced a remarkable decrease of membrane C/PL molar ratio. Nevertheless IMPA normalization did occur 'in vivo', when the SCA cells were exposed to therapeutic 'plasma exchange' (3.3 litre/week). The results suggest the following conclusions: (a) in our SCA patient there is an increased IMPA; (b) this feature, as well as membrane lipid alteration, is transferable to normal erythrocytes; (c) this case seems to demonstrate, for the first time in our knowledge, a modulating effect of plasma on IMPA in erythrocytes.

Acanthocytes↗
PubMed1988

Effects of dietary fish oil on malondialdehyde production and glutathione peroxidase activity in hyperlipidaemic patients.

In 20 adult patients suffering from hyperlipidaemia we measured the lipid composition of erythrocyte membrane, the glutathione peroxidase activity in both erythrocytes and platelets, the production of malondialdehyde by platelets stimulated with thrombin, as well as the level of plasma selenium, retinol and alpha-tocopherol, before and after 8 weeks of fish oil supplementation (20 ml daily). We noted a remarkable reduction in plasma triglycerides which was associated with a significant decrease in blood pressure; moreover, we noted a reduction in the amount of arachidonic acid compensated by an increment of omega-3-fatty acid (particularly eicosapentaenoic and docosahexaenoic acids). The dietary supplementation with fish oil was associated with a significant increase in glutathione peroxidase activity in both erythrocytes and platelets. On the contrary, the production of malondialdehyde, which was originally higher than normal in hyperlipidaemics, was inhibited significantly after fish oil (p less than 0.001). Whereas no changes were observed in the concentration of plasma selenium and alpha-tocopherol, an increment of plasma retinol occurred. These data indicate that in hyperlipidaemics there is a proaggregant status; this situation may be normalized by using a dietary supplementation of fish oil; the increase of polyunsaturated fatty acids on the cell membrane, with a possible increment of the formation of lipoperoxides, induced by fish oil, is compensated by an increased activity of the scavenger enzyme glutathione peroxidase.

Adult↗
PubMed1987

Membrane polyunsaturated fatty acids and lithium-sodium countertransport in human erythrocytes.

Two groups of individuals, 26 normotensive normolipemic and 37 normotensive hyperlipemic, all without family history of hypertension have been selected in attempt to demonstrate whether Li-Na countertransport of erythrocytes is influenced by plasma and membrane lipid composition. The maximal rate of Li-Na countertransport was elevated in hyperlipemics (0.344 +/- 0.168 vs 0.220 +/- 0.074 mmol/l erythrocytes/h). This difference is highly significant. Hyperlipemics had different composition of membrane lipids than normals. The most important variations were: increase of palmitic, palmitoleic and total saturated fatty acids (SFA) as well as increase of cholesterol/phospholipids ratio (C/PL); in contrast, hyperlipemics had a reduced amount of linoleic acid and total unsaturated fatty acids (UFA) as well as total polyunsaturated fatty acids (PUFA). Consequently, UFA/SFA and PUFA/SFA ratios were lower than in normals. Li-Na countertransport was negatively correlated with the amount of PUFA (P less than 0.02), whereas it was positively correlated with the following parameters: oleic/linoleic ratio (p less than 0.02), monounsaturated fatty acids/polyunsaturated fatty acids ratio (p less than 0.03) as well as with the SFA + monounsaturated fatty acid/PUFA ratio (p less than 0.03). These findings suggest that the V max of Li-Na countertransport in erythrocytes is influenced by the lipid composition of the membrane.

Adult↗
PubMed1986

Identification of the uterine factor(s) which induce the acrosome reaction in buffalo (Bubalus bubalis) spermatozoa.

This study characterizes factors present in uterine fluid from oestrous buffaloes which induce the acrosome reaction in buffalo spermatozoa. Characterization was performed by dialysis, heat treatment (90 degrees C, 30 min) and deproteinization of uterine fluid. The % motility and viability of sperm was maintained better in unfractionated uterine fluid than in dialysed fluid. Heating and deproteinization of the dialysed uterine fluid significantly reduced the % motility and viability of sperm. The percentage of sperm showing different stages of the acrosome reaction (swelling, and vesiculation) was significantly higher for sperm incubated in dialysed than in neat uterine fluid. There was no significant difference in the % of sperm showing acrosome shedding in both dialysed and neat uterine fluid. Heat treatment destroyed the ability of uterine fluid to induce the acrosome reaction. Sperm incubated in the protein precipitate from uterine fluid showed all stages of the acrosome reaction. Thus, the uterine factor(s) responsible for inducing the acrosome reaction in buffalo sperm was associated with the non-dialysable, albumin-like protein fraction and was heat-labile.

Acrosome↗
PubMed1981

["In vitro" stimulation of TBArs. Production by carbon tetrachloride in MH1C1 hepatoma (author's transl)].

It is well known that lipid peroxidation is absent or extremely low in tumour tissues. So the lack of lipid peroxidation is so far considered as a peculiar characteristic of tumour cells. Studying lipid peroxidation in three different hepatomas, we have found, however, results suggesting that the lack of lipid peroxidation cannot be retained anymore as a constant attribute of hepatoma cells. In fact, we studied the TBArs production in homogenates of the following hepatomas: AH-130 Yoshida , 3924 A Morris, MH1C1 hepatomas, in comparison with normal liver. Whereas we were able to confirm that TBArs production in Yoshida tumour is extremely low, we found that Morris 3924 A hepatoma, growing subcutaneously in the rat, displays a rather consistent TBArs production. Moreover, MH1C1 hepatoma, grown in cell culture, produces more TBArs than normal liver. AH-130 Yoshida tumour is unable to metabolize CC14. Consequently, the addition of CC14 to the homogenate doesn't stimulate TBArs production, as this substances does in the case of normal liver homogenate. A good increase in TBArs production was seen, however, with MH1C1 homogenate.

Animals↗
PubMedDate not supplied

Membrane fatty acids and erythrocyte Li-Na countertransport in nephrotic syndrome and their relationship.

Cholesterol/phospholipids molar ratio and fatty acid composition have been estimated in erythrocyte membrane of 12 patients suffering from nephrotic syndrome and compared to values obtained in 23 normal subjects matched for sex and age. The membrane lipid composition has been correlated with the activity of erythrocyte Li-Na countertransport of the same subjects. The results show a significant increase in cholesterol/phospholipids ratio and total saturated fatty acids when erythrocytes of nephrotic patients are compared to normal erythrocytes, whereas total unsaturated fatty acids were lower in nephrotics (p less than 0.002). Li-Na countertransport was higher in nephrotics (p less than 0.001) and it was positively correlated with the total amount of saturated fatty acids of the erythrocyte membrane (r = +0.451; p less than 0.01). On the contrary, Li-Na countertransport was negatively correlated with the total amount of unsaturated fatty acids (r = -0.468; p less than 0.01).

Adult↗
PubMedDate not supplied

Light-induced storage in layer-by-layer films of chitosan and an azo dye.

The buildup of layer-by-layer (LBL) films from chitosan and the azodye Ponceau-S (PS) was investigated under various experimental conditions, and the resulting films were used in optical storage experiments. The kinetics for the writing process in optical storage was faster for LBL films prepared at low pHs, probably because the films had a larger free volume for isomerization of the chromophores. The nanostructured nature of the LBL films also affected the crystallinity of chitosan, which was considerably decreased in this type of film as chitosan became protonated because of the electrostatic interactions between adjacent layers.

Azo Compounds↗
PubMedDate not supplied

The dyspeptic syndrome in migraine: morphofunctional evaluation on 53 patients.

The authors, in order to evaluate the important role of gastrointestinal dysfunction during the migraine attack, have studied 53 patients with migraine without aura during the asymptomatic stage between attacks. Patients were examined functionally with a pH meter test of the gastroesophageal tract over 24 hours and morphologically with esophagogastroduodenoscopy. The results of this study point out that in a high percentage of patients with migraine, both evaluations are normal. The authors suggest the possibility of detecting, even hypothetically, an alteration of the common neurotransmitter substrate in the origin of migraine attacks and accompanying symptoms.

Adult↗
PubMedDate not supplied

Sumatriptan overuse in episodic cluster headache: lack of adverse events, rebound syndromes, drug dependence and tachyphylaxis.

This observational study was designed to examine the pattern of sumatriptan use in patients with cluster headache using more than the recommended daily dose of subcutaneously injected (s.c.) sumatriptan. Thirteen patients suffering from episodic cluster headache were asked to record the characteristics of their attacks and drug intake for 1 year. All reported a high daily frequency of attacks (more than 3 per day) and the related overuse of s.c. sumatriptan. The results show that the overall incidence of adverse events among patients receiving sumatriptan injections for the treatment of cluster headache is low. The extended administration of this drug in episodic cluster headache did not result in tolerance problems or tachyphylaxis. Only 4 patients experienced minor adverse events and recovered more slowly than the others. They suffered from migraine without aura and cluster headache, and showed a family history of migraine. Even though they must be viewed with caution, due to the observational nature of the study and the low number of patients included, these results suggest that the profile of sumatriptan may differ in cluster headache compared with migraine.

Adult↗