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Biomedical subjects

G Gatti

Publications and source records attributed to G Gatti.

At least 181 records · Page 10Linked to original sources
PubMed1983

Selective crystallization of horse isoferritins.

Various precipitating agents were examined in order to crystallize horse heart and spleen ferritins. Cadmium sulfate induced the crystallization of the spleen ferritin, while 2-methyl-2,4-pentanediol and poly(ethylene glycol) only induced that of the heart ferritin. Isoelectric focusing analysis showed that the crystals grown from cadmium sulfate contained only the more acidic isoferritins, and those grown from methyl pentanediol only the less acidic isoferritins. Heart ferritin crystallizes in a cubic space group, as previously reported for spleen ferritin crystals grown from cadmium sulfate.

Animals↗
PubMed1983

Reduction of phenytoin clearance caused by cimetidine.

The effect of cimetidine on the disposition kinetics of phenytoin was investigated in 7 healthy volunteers. Each subject received a single intravenous dose of phenytoin on two occasions, in the control state, and during concurrent treatment with cimetidine 1 200 mg/day for 6 days. A slight but statistically significant decrease both in the rate of elimination and total body clearance of phenytoin was observed during the administration of cimetidine. The effect is probably due to inhibition of metabolism.

Adult↗
PubMed1983

The effect of alpha-latrotoxin on the neurosecretory PC12 cell line: studies on toxin binding and stimulation of transmitter release.

alpha-Latrotoxin of black widow spider venom was found to bind with high affinity (KA = 1.8 X 10(9)M-1) to specific sites present in discrete number (approximately 6300/cell, approximately 12/micron2) at the surface membrane of PC12 cells. This binding correlated with (and therefore, probably caused) the secretory response produced by the toxin. Binding was enhanced (approximately 2-fold) in the presence of mM concentrations of various divalent cations (Ca2+, Mn2+ and Co2+) while Ba2+ and Sr2+ had a smaller effect and Mg2+ was inactive. Hypertonicity, concanavalin A and trypsin pretreatment of the cells blocked the binding interaction. The alpha-latrotoxin-induced stimulation of 3H-dopamine release was massive and occurred very rapidly when cells were exposed to the toxin in a Ca2+-containing Krebs-Ringer medium, whereas it occurred at a much slower rate in a Ca2+-free, Mg2+-containing Ringer. Introduction of Ca2+ into the latter medium resulted in a shift of the release rate from slow to fast. In contrast, in divalent cation-free medium the response was abolished. The toxin-induced secretory response was unaffected by Na+ and Ca2+ channel blockers (tetrodotoxin and D600) as well as by calmodulin inhibitors (calmidazolium and trifluoperazine). The effects of Ca2+ and Mg2+ were found to be concentration-dependent, with half maximal responses occurring at approximately 0.3 and 1.5 mM for the two divalent cations, respectively. Other divalent cations could substitute for Ca2+ and Mg2+, the relative efficacy being Sr2+ greater than Ca2+ greater than Ba2+ much greater than Mn2+ greater than Mg2+ greater than Co2+. Moreover, the response occurring at suboptimal concentration of Ca2+ (0.4 mM) was potentiated by the concomitant addition of either Mg2+, Mn2+ or Co2+. The effect(s) of divalent cations in supporting the alpha-latrotoxin-induced release response seem(s) to occur primarily at step(s) beyond toxin binding because (a) the stimulatory effects of the various cations on release were not matched by parallel effects on binding, and (b) Ca2+ maintained its ability to stimulate fast release even when toxin binding had occurred in a Ca2+-free medium. Delays in the release responses were observed when cells were exposed to alpha LTx in Na+-free, glucosamine or methylamine-based media, or depolarized with high K+ (in the presence of D600) before toxin treatment. Moreover, in these two conditions the ability of Mg2+ to support the alpha LTx response was considerably decreased.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1982

[Functional aspects of neutrophils in full-term infants].

The measure of superoxide anion (.O2-) generation was carried out in the neutrophils (PMNs) of newborns. Comparison between .O2- generation in the resting state and after stimulation with zymosan was considered. PMNs were incubated in their own plasma and in plasma from healthy adult subjects. The results demonstrate a decrease of .O2- generation (in comparison with adult PMNs) in the PMNs from newborn when they were incubated in their own plasma while the .O2- generation reached the values equal to adult's PMNs when the cells of newborns were incubated in the adult's plasma. However PMNs from some newborns demonstrated a low .O2- generation even though they were incubated in adult's plasma. The data are suggestive of a predominant, but not always exclusive, responsibility of plasma factors in the decrease .O2- generation by PMNs of full term babies.

Adult↗
PubMed1982

[Separation of erythrocytes from full-term infants into different age populations].

Separation of erythrocytes into fractions of different age was carried out by the method of discontinuous gradient. Five fraction of various specific density were prepared and in each fraction age dependent enzyme activities PK and G-6-PD were assayed. The erythrocytes from cord blood and from newborn 4-5 days old were studied. The results demonstrate the correlation between density and erythrocyte age in both cord blood and blood from newborns. However, 4-5 days old demonstrate a shift of various populations toward fractions of higher density.

Cell Separation↗
PubMed1982

Urinary enzyme excretion and renal lactate dehydrogenase isoenzyme pattern in acute HgCl2 nephropathy of rat.

The activity of several enzymes with different intracellular sites was determined in urine at various times following nonfatal acute tubular necrosis induced by mercuric chloride administration. The excretion rate of all tested enzymes rose on the 1st and 2nd day; in the next observations (days 7-15) enzymatic values approached the basal values. The lactate dehydrogenase isoenzyme pattern of the renal cortical zone showed an early shift towards cathodic fractions and later (7 days) an increase of middle ones; the normal anodic zymogram recovered after a suitable time interval (30 days). The isoenzymatic changes are related both to the renal hypoxia and to the appearance of less differentiated cells. The behaviour of functional parameters (urine flow, osmolality, urea clearance, creatinine clearance) were well in agreement with the observed enzyme and renal isoenzyme changes.

Acid Phosphatase↗
PubMed1981

[Renal tubular damage after rapid intravenous contrast study with iopamidol].

Reference is made to results obtained in 53 nephropathics in the study of urinary elimination of alphaglycosidase and lysozyme before and after rapid contrastography with sodium and meglumine diatrizoate and with iopamidol. A statistically significant difference in alphaglycosidase was evident with both media, whereas no change was noted for lysozyme. As far as the evaluation of alphaglycosidase was concerned, the tubular alteration induced by each medium was the same in terms of statistical comparison of the mean differences before and after urography.

Contrast Media↗
PubMed1981

[Nephrangiotomography with iopamidol in renal insufficiency].

An account is given of a study of 118 patients, including 67 with renal failure of varying severity, examined nephrangiotomographically with the aid of both a non-ionic contrast medium (iopamidol) and a conventional medium (sodium diatrizoate and methylglucamine). It is shown that the advantages presented by rapid injection of the medium, and the obtaining of prompt vascular data, are accompanied by those offered by the non-ionic medium, since it induces reduced osmotic diuresis, which permits satisfactory visualisation of the excretory ducts, even in patients with very low glomerular filtration values.

Adolescent↗
PubMed1981

[Immunological aspects of diabetes].

The incidence of immunological disorders seems to play a primary, significative role in the genesis of insulin-dependent diabetes mellitus (IDDM). Auto-immunological anti-pancreas alterations, both cell-mediated and humoral, have been detected in course of IDDM; moreover, the presence of antipancreatic antibodies seems to correlate with progressive destruction of islet cells and increased insulin deficiency. Animal models and human studies, revealing the pathologic entity of "insulitis", are consistent with an autoimmune component playing a part in the pathogenesis of diabetes mellitus. Furthermore, genotypic factors may be considered: recent studies prove the association between HLA system and IDDM; specifically, HLA antigens B8 and BW15 are found in significantly higher frequencies in juvenile onset insulin-dependent diabetics. Therefore, it can be hypothesized, in the pathogenesis of the disease, an altered immune response to an additional environmental diabetogenic factor; it has been postulated, on the ground of epidemiologic and experimental studies, the interference of a viral infection, that may act as a triggering event to pancreatic cell damage with a latent period of variable duration.

Adolescent↗
PubMed1980

Interaction between phenytoin and valproic acid: plasma protein binding and metabolic effects.

The effect of sodium valproate (400 mg three times daily) on the disposition kinetics of intravenous phenytoin (250 mg) was investigated in seven normal subjects. After valproate, the free (unbound) fraction of phenytoin in serum rose from 9.6 +/- 0.9% (SD) to 15.6 +/- 1.4% on average (p < 0.001). The effect was associated with an increase in systemic clearance and apparent volume of distribution of total drug. There was a strong positive correlation between percent increment in each of these parameters and percent increment in unbound drug in serum. Free phenytoin concentration in serum and phenytoin concentration in saliva increased during valproate administration. As a result, both the clearance and the apparent volume of distribution of free drug were reduced. There was an increase in the renal excretion of unchanged phenytoin during valproate administration, but the effect was too small to have an appreciable influence on the overall clearance of the drug. There were no consistent changes in the excretion of the major metabolite 5, p-hydroxyphenyl, 5-phenyl, hydantoin (pHPPH), in the urine. These results suggest that valproic acid may have two separate and opposing effects on phenytoin disposition: (1) displacing phenytoin from plasma protein binding sites, thereby enhancing the systemic clearance of total drug, and (2) inhibiting phenytoin metabolism, thereby increasing the concentration of free drug in the serum.

Adult↗