Showing papers by "University of Perugia published in 1981"

Effect of cytidine diphosphate choline (CDP-choline) on ischemia-induced alterations of brain lipid in the gerbil

Abstract: Brain ischemia was produced in gerbils (Meriones unguiculatus) by the bilateral ligation of the carotid arteries. Definite changes in the energy status of brain demonstrated that carotid occlusion was effective. Five minutes before ligation, an intraventricular injection of either saline or cytidine diphosphate choline (CDP-choline, 0.6 μmol/brain, 3μl) was given to groups of animals. Control animals, with and without CDP-choline, together with the ischemic groups, were decapitated directly into liquid nitrogen; 10 min after arterial ligation. Brain free fatty acids, neutral lipids and phospholipids, which were labeled in vivo by the intraventricular injection of [1-14C] arachidonic acid (0.4–0.6 μCi, 6–9 nmol) 2 hr prior to ligation, were extracted, purified, and separated by thin-layer chromatographic procedures. The CDP-choline treatment noticeably corrected the increase of total and individual fatty acids due to ischemia and the increase of their radioactivity content. The changes in neutral lipids, particularly in the diacyl glycerol fraction, were also corrected by the injection of the nucleotide. CDP-choline partially reversed the decrease of brain phosphatidylcholine and of its labeling, which was due to ischemia. All the data indicate that the prior injection of CDP-choline stimulates the choline phosphotransferase reaction of brain towards synthesis of phosphatidylcholine and prevents the release of free fatty acids, particularly of arachidonic acid, associated with ischemia.

The Importance of Determining Irreversibly Glycosylated Hemoglobin in Diabetics

Abstract: The concentration of glycohemoglobins (HbA 1(a+b+c) , HbA 1 ,) was measured before and after incubation of normal and diabetic erythrocytes for 6 h at 37°C in saline. This procedure removes as much as 80-90% of the labile glucose-HbA 0 adduct (labile HbA 1 ,), thus allowing accurate estimation of irreversibly glycosylated hemoglobin (stable HbA 1 ,). The concentration of HbA 1 measured before such an incubation is total HbA 1 , (stable + labile). We determined the concentration of total, stable, and labile HbA 1 , in the same blood samples used to measure fasting plasma glucose (FPG) every day, for 4 consecutive days, in two groups of hospitalized insulin-treated diabetics. Group A subjects ( N = 7) were type I, C-peptide negative, unstable diabetics, while group B subjects ( N = 15) were type II, C-peptide positive, stable diabetics. Individual day-to-day variations of total HbA 1 , were wide in group A (Δ = 1.58 ± 0.14%), and slight in group B (Δ = 0.12 ± 0.01%; P 1 , were virtually absent not only in group B subjects with stable glycemic values (Δ = 0.08 ± 0.01%), but also in those of group A with marked glycemic instability (Δ = 0.07 ± 0.01%; P = NS). Day-to-day variations of labile HbA 1 , were marked in group A (Δ = 1.31 ± 0.14%), but negligible in group B (Δ = 0.15 ± 0.03%; P 1 , in group A ( r = 0.89) and B ( r = 0.71). FPG correlated with stable HbA 1 , in group B ( r = 0.73) but not in group A subjects and with total HbA 1 , more closely in group B ( r = 0.73) than in A ( r = 0.61). A very close correlation was found between the concentration of total and labile HbA 1 in subjects of group B ( r = 0.82). In group B, fasting, post-breakfast, and mean daily plasma glucose values, determined every 3-6 days during the 2 mo before admission, significantly correlated both with total and stable HbA 1 determined on admission, while in group A they did not. In group A, the correlation was significant when stable instead of total HbA 1 was considered. We conclude that the significant fluctuations of total HbA 1 reduce its value as an index of long-term control in unstable diabetics. On the other hand, a single determination of stable HbA 1 , totally independent of simultaneous blood glucose values, closely reflects blood glucose control over the previous 2 mo. We propose routine estimation of stable HbA 1 , which is simple and straightforward, to carry out follow-up studies of unstable diabetics.

The distribution and reproduction of triops cancriformis (bosc) in europe (crustacea, notostraca)

Abstract: SUMMARY A large number of an unidentified species of Encyrtoscelio Dodd was collected on coastal sandy dunes in Somalia, mainly in the retrodunal zone. This genus includes only a few species of which very little is known from a bionomic point of view. The daily rhythm has two peak periods of activity, the highest at sunset and the other, smaller, at dawn. Females and wingless specimens are more predominant than males and winged ones. It is suggested that the host of this Encyrtoscelio sp. could be the Heteroptera Cydnidae Aethus perithrix (Mc.) and it is concluded that the habitat of this genus is provided by sandy places.

Immunoadjuvant effects of Candida albicans and its cell wall fractions in a mouse lymphoma model

Abstract: Chemical, ultrastructural, and immunoadjuvant properties of Candida albicans (CA) and of a number of its fractions have been characterized through the analysis of the antitumor activity of soluble and insoluble cell wall components.

Suppression of natural killer (NK) activity by splenic adherent cells of low NK-reactive mice

Abstract: Adherent cells with the ability to inhibit NK activity were found in the spleens of young 8-week-old SJL/J mice. Such suppressor cells were also found in the spleens of other low-NK-reactive strains, but not in the spleen of age-matched high-NK-reactive strains. These suppressor cells had the characteristics of macrophages, since they were plastic- and nylon-adherent, phagocytosed latex and iron particles, and were resistant to treatment with anti-Thy-1.2 serum plus complement. Their inhibitory activity appeared to be due to their production and/or release of soluble suppressive factor(s). Their suppressor activity was similar to that of pyran copolymer-activated macrophages, which were previously shown to be suppressive for cytotoxicity by NK cells. We suggest here that macrophages may be involved in the physiological regulation of NK activity and may contribute to the low NK activity in some strains of mice.

Optimum Continuous Block Designs

Abstract: The incidence matrix of a block design is replaced by a normalized version, N, in which the entries are non-negative numbers whose sum is unity. The so-called C-matrix, the information matrix for estimation of treatment contrasts, is similarly replaced by the normalized analogue C(N). We study the set of ordered eigenvalues of all C(N) and give a complete specification for three treatments (rows). For any number of treatments we characterize the eigenvalues of an important subclass of designs for which the non-zero entries in any given block are equal. It is suggested that the natural ordering between designs is upper weak majorization of the eigenvalues. Using this we show how to improve a given N-matrix and this leads to several optimality statements.

Lysozyme distribution in healthy human skin

Abstract: Lysozyme is present in human skin as well as in other tissues and secretions [2, 4]. Previous personal investigations [1] demonstrated lysozyme activity of between 85 and 195 lag/g wet weight (average 142 lag/g wet weight) in the skin of clinically healthy subjects. Indirect immunofluorescence studies [3] revealed that lysozyme is mainly located in the cytoplasm of epidermal cells and that only small quantities are present along the dermal collagen bundles. Forty hospitalized volunteers of both sexes, aged between 19 and 71 years, were studied. All were free from clinical infections and had only limited traumatic or proliferative skin lesions. Lysozyme activity was determined in both serum and 0.5 mm thick samples of skin taken from the lumbar region and treated according to Binazzi et al. [1]. Histochemical studies were carried out on fine frozen sections of skin removed from the same area and/or from the internal surface of the forearm in an identical condition. Immunofluorescence was performed by the routine technique using antihuman milk muramidase rabbit IgG (Dakopatts, Denmark) and ITCF-labeled antl-~rabbit IgG swine serum (Dakopatts, Denmark). The peroxidase conjugate method (Table 1) was used for the immunoperoxidase studies. Controls were performed by absorbing the primary anti-human muramidase antiserum on purified human milk lysozyme before immunostaining, thus blocking the reactivity for muramidase. Lysozyme activity was found to be between 1.25 and 18 lag/ml (average 5.15 lag/M) in serum and between 75 and 198 lag/g wet weigth (average 119.5 lag/g wet weight) in skin samples. These results did not show significant differences with respect to those previously reported [1].

Phospholipid metabolism in neuronal and glial cells during aging

Abstract: The incorporation of cytidine-containing precursors (CDP-Cho and CDP-Etn) into the main phospholipid classes of cellular fractions enriched in neurons and glial cells from whole rat brains of different ages was examined. The rate of synthesis of choline phosphoglycerides in neuronal homogenates significantly decreased with age up to 18 months; after this time no additional decrease was found. The decrease of CDP-Etn incorporation in neurons was found to be less significantly affected by age up to 18 months, but the enzymic activity decreased after 18 months of age. No changes were found in the corresponding glial activity at any age. Biochemical phenomena that occur in 18-month-old rat brain (aged animals) were compared with phenomena occurring in 2-month-old rat brain (adult animals). No significant variations of lipid composition were found in neurons from either 18-month-old or 2-month-old rat brain. These results, together with some kinetic parameters, suggest that ethanolamine and choline phosphotransferases are affected differently by aging.

Grape seed: A potential source of protein

Abstract: Because grape seed is a potential source of edible protein, it is essential to remove the polyphenols to significantly improve protein digestibility. This study describes a procedure whereby grape seed protein concentrate is significantly purified and protein digestibility is improved. The procedure involves soaking whole seeds in an alkaline solution and subsequently extracting the protein with a concentrated salt solution.

Impairment of in vitro generation of cytotoxic or T suppressor lymphocytes by Friend leukemia virus infection in mice.

Abstract: Spleen cells collected from DBA/2 (H-2d) mice inoculated with the polycythemic variant of Friend-Leukemia Virus Complex (FLV-P) were tested for T-dependent immune functions, such as the in vitro generation of cytotoxic T lymphocytes (CTL) and of non-specific T suppressor lymphocytes (STL). CTL were generated against H-2b splenocytes, and STL were obtained following a 5-day lymphocyte culture without stimulator cells. A progressive and severe impairment of the generation of both CLT and STL was found from 2 weeks onward after infection, being almost totally abolished 3-4 weeks after virus challenge. Suppressor cells (SC) capable of inhibiting CTL generation was detected in FLV-P bearing mice. Suppressor activity was unaffected by anti-Thy 1.2 serum and complement but was removed following iron-magnet depletion or passage through nylon-wool column. Moreover complete recovery of the competence of CTL generation was attained when FLV-P infected splenocytes were passed through nylon-wool column. It is concluded that FLV-P infection depresses T-dependent cytotoxic and suppressor responses in mice, by the appearance of non-T adherent phagocytic cells, capable of impairing CTL generation in vitro.

Reference values and characteristics of brain stem audiometry in neonates and children

Abstract: ABR (Auditory Brainstem Response) delivering the acoustic stimulus both through a headphone (PHN) and in free field (FF), have been recorded in 59 "normal" children divided into four age-related groups: (1) 22 children born at a gestational age ranging between the 36th and the 41st week; (2) 12 with ages ranging from 1 to 6 months; (3) 15 with ages ranging from 6 to 12 months; (4) 10 with ages ranging from 12 to 36 months. Peak latency values obtained with FF technique have been corrected by calculating the delay due to the distance between the loudspeaker and the tested ears (2.04 ms). When using this correction, no statistically significant differences were found between latency values of peaks JI and JV recorded using the two technique. While JI latency values of various groups do not differ significantly, groups 2--and especially group 1--JV latency values are statistically different from those of the 3rd and 4th group. This observation was confirmed by JV--JI interval values. JV wave in neonates (group 1), using PHN technique, is detectable at 60 dB p.e. SPL (82%) while in all other groups at 60 dB this wave is clearly detectable in all children (100%). Using FF technique, JV wave is still visible at 60 dB in 78% of the neonates (group 1) and in almost all children of the other groups. Considering ABR waveform, using PHN technique, in the first two groups only three waves are visible and the first one disappears at about 80 dB, while the typical 4--5 waves of normal adult tracings are detectable since 8--12 months of age. FF tracings instead show three peaks in all groups, the first (JI) being less evident when compared with the one obtained using PHN technique. JV amplitude values observed in FF are higher than those obtained delivering the stimulus through the headphone.

Occurrence and Properties of Phospholipases A1 of Plasma Membranes Prepared from Neuronal- and Glial-Enriched Fractions of the Rabbit Cerebral Cortex

Abstract: Exogenously added glycerophosphatides, specifically radioactively labelled either in the 1 or in the 2 position, were used to investigate the occurrence and properties of phospholipase A1 in plasma membranes prepared from neuronal- and glial-enriched fractions of rabbit brain. Phospholipase A1 activity was maximal at pH values ranging between 8.0 and 9.0 for the plasma membranes of both cell types. The enzyme activity was most abundant in the microsomal fraction, with a neurondglial ratio of about 2. The plasma membranes displayed about half the enzymic activity of the microsomal fraction, whereas only small amounts of phospholipase A1 were present in the neuronal and glial mitochondria. Investigations on the substrate specificity showed a different pattern for the enzyme of neuronal and glial origin. The release of labelled fatty acids from phosphatidylcholine by the neuronal plasma membrane phospholipase A1 decreased with increasing degree of unsaturation of the fatty acids at the 1 position. The presence of plasmalogens and plasmalogen precursors in the incubation mixture appreciably inhibited the hydrolysis of the corresponding diacyl compounds.

Polyacrilonytrile versus cuprophan membranes for hemodialysis: evaluation of efficacy and biocompatibility by platelet aggregation studies.

Abstract: The short- and long-term effect of hemodialysis with two different membranes -- cuprophan and polyacrilonytrile -- on platelet aggregation has been investigated in 12 uremic patients undergoing extracorporeal dialysis, passing from one treatment to the other. Cuprophan membranes failed to correct the defective platelet aggregation of uremia, and their thrombogenicity was documented by a fall in platelet count and further impairment of platelet aggregation during dialysis. On the contrary, polyacrilonitrile membranes showed the capacity to correct completely but transiently the platelet aggregation, without changes in platelet count. The results indicate that polyacrilonytrile membranes show a better biocompatibility toward platelets than cuprophan membranes.