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Biomedical subjects

G Esposito

Publications and source records attributed to G Esposito.

At least 235 records · Page 13Linked to original sources
PubMed1990

4-Substituted 1-phenyl-1H-indazoles with analgesic, antiinflammatory, antipyretic and local anesthetic activities.

The synthesis of amides 3 and 4 starting from (1-phenyl-1H-indazol-4-yl)acetic and [(1-phenyl-1H-indazol-4-yl)oxy]acetic acids, respectively, as well as of 2-(1-phenyl-1H-indazol-4-yl)ethanamines 5 starting from 3, is described. Moreover, a number of 2-[(1-phenyl-1H-indazol-4-yl)oxy]ethanamines 7 and 3-[(1-phenyl-1H-indazol-4-yl)oxy]propanamines 8 were prepared starting from 1-phenyl-1H-indazol-4-ol. Some compounds 3, 4 and 7 showed an appreciable analgesic activity in mice, whereas compounds 4 were moderately active as antiinflammatory agents in rats. Some compounds 3, 4, 5, 7 and 8 showed also local anesthetic and a weak antipyretic activity in mice and rats, respectively.

Anesthetics, Local↗
PubMed1989

1H-NMR studies of synthetic polypeptide models of Plasmodium falciparum circumsporozoite protein tandemly repeated sequence.

The major immunodominant region of the coating protein of Plasmodium falciparum sporozoites contains multiple tandem copies of the sequence Asn-Ala-Asn-Pro (NANP). Current efforts for the development of an antisporozoite vaccine are focused on the synthesis of polypeptides reproducing part of the circumsporozoite protein repeat sequence and, in an attempt to relate conformational properties and biological response, 1H-nmr one- and two-dimensional studies of the synthetic models (NANP)2NA and (NANP)6 were carried out in water and water/methanol mixtures, at 400 and 500 MHz. In water, (NANP)6 undergoes fast conformational averaging. At variance, in water/methanol, the molecule appears to adopt an extensive structure, but detailed analysis is impaired by high spectral degeneracy. Based on the results obtained with (NANP)2NA and from preliminary experiments in water/trifluoroethanol, an interpretation is suggested for the (NANP)6 data in water/methanol in terms of a mixed sequence of beta I-turns and half-turns (or/and gamma I-turns) around the positions Ni-1-Pi-Ni + 1.

Animals↗
PubMed1989

Open heart surgery in the first 24 hours of life.

The results of open heart surgery in infants have steadily improved. The performance of corrective surgery very early in life has thereby been encouraged. We report four patients who underwent successful surgical correction within 24 h of birth. Two patients with total anomalous pulmonary venous drainage and one patient with pulmonary atresia and intact septum were corrected with the aid of profound hypothermia by the combined surface and bypass cooling technique. Cardiopulmonary bypass alone was used for the fourth patient with aortic stenosis. The usual surgical techniques can be applied successfully to infants even within 24 h of life.

Aortic Valve Stenosis↗
PubMed1988

Na+/H+ exchange mechanism in the basolateral membrane of the rat enterocyte.

Basolateral membrane vesicles from rat jejunal enterocytes, especially purified of brush-border contamination, were used for Na+ uptake. The basolateral membrane vesicles are osmotically active and under our experimental conditions Na+ binding is much lower than transport. An outwardly directed proton gradient stimulates Na+ uptake at both 5 microM and 5 mM concentrations. The proton gradient effect can be inhibited completely by 2 mM amiloride and partially by either FCCP or NH4Cl (NH3 diffusion). Membrane potential effects can be excluded by having valinomycin plus K+ on both sides of the vesicles. These results suggest that there is an Na+/H+ exchanger in the basolateral membrane of rat enterocytes.

Ammonia↗
PubMed1988

Ouabain-insensitive active sodium transport in rat jejunum: evidence from ATPase activities, Na uptake by basolateral membrane vesicles and in vitro transintestinal transport.

The basolateral membrane of the jejunal enterocyte of the rat was separated by self-orienting Percoll-gradient centrifugation and further purified from brush border contamination. Pellets were analysed for Mg-, Na- and (Na,K)-ATPase activities. The uptake of 0.02 M NaCl was also followed by the rapid micro-filtration technique. Transintestinal transport of fluid and electrolytes, and cell water, Na and K were determined in the in vitro everted and incubated jejunum. There is ouabain-insensitive Na-ATPase in addition to the well-known (Na,K)-ATPase in the basolateral membrane. These are differently inhibited by furosemide and ethacrynate. Na uptake by osmotically active basolateral membrane vesicles is enhanced by ATP and a further enhancement is obtained if there is intravesicular K. The ATP effect is inhibited differently by strophanthidin, furosemide and ethacrynate. In the everted sac preparation, transintestinal transport of Na and fluid still occurs when the Na/K pump is totally inhibited by ouabain. These experimental results suggest that there is also a ouabain-insensitive Na pump, different from the Na/K pump, in the basolateral membrane.

Adenosine Triphosphatases↗
PubMed1988

Giant left atrium and mitral valve replacement: risk factor analysis.

Giant left atrium (GLA) associated with mitral valve disease (MVD) has been reported as a significant risk factor in mitral valve surgery with mortality ranging from 8%-32%. Plication of the left atrium has been suggested to reduce postoperative left ventricular failure, respiratory failure and mortality. The 203 consecutive patients with MVD operated upon between 1980 and 1986 were reviewed and divided in two groups: group A without GLA (165 patients) and group B with GLA (38 patients = 19%). The pertinent preoperative and intraoperative notes and the early and late postoperative course were reviewed and correlated. The hospital mortality was 2.4% in group A and 2.6% in group B. Late mortality, at a mean follow-up of 54 months was 4.3% in group A and 5.4% in group B. In this series, GLA was not a significant risk factor in MVR and did not affect early and late results as compared with cases without GLA. Plication may not be required in absence of extracardiac signs of compression.

Cardiomegaly↗
PubMed1988

Ouabain-insensitive Na-ATPase activity in the basolateral membrane from rat jejunum.

1. In the basolateral membrane preparation of the rat enterocyte (jejunal tract) there is not only the well-known (Na,K)-ATPase activity, but also a ouabain-insensitive Na-ATPase. 2. The Na-ATPase is not activated by anions or other monovalent cations. As a substrate, ATP cannot be replaced by other nucleotides. 3. The Na-ATPase is insensitive to ouabain and bumetanide, inhibited partially by furosemide and totally by ethacrynate. 4. The activation of Na-ATPase at different Na concentrations shows an hyperbolic curve (Km = 15.7 +/- 2.3 mM and Vmax = 204 +/- 19 nmoles Pi/mg protein per min) different from the sigmoidal curve (Km = 9.8 +/- 1.2 mM and Vmax = 640 +/- 15 nmoles Pi/mg protein per min) shown by (Na,K)-ATPase. 5. These results are compared with the corresponding ones found in other animals and tissues in which the Na-ATPase was found. 6. The Na-ATPase activity can be interpreted as the enzymatic correspondent of a ouabain-insensitive Na pump, present in the basolateral membrane of the enterocyte different in behaviour with respect to the known Na pump.

Adenosine Triphosphatases↗
PubMed1988

d-amphetamine and active behavior--induced changes of regional brain ascorbic acid levels in the rat.

In male Wistar rats, shuttle-box avoidance test (5 daily sessions of 50 min) significantly decreased (P less than 0.001) by 30% ascorbic acid (AsAc) level in hypothalamus (HYP), while it left it unmodified in striatum (ST) and in the remaining brain (RB), as opposed to untested rats; AsAc level in HYP showed a significant (P less than 0.001) trend to recovery 24 hours after the end of the test. No correlation was found between the rate of conditioned avoidance responses (CAR) and AsAc levels in the above brain regions. d-Amphetamine (d-A), given s.c. at the dose of 1.0 mg/kg/day for 5 consecutive days, significantly increased AsAc levels by 26% in HYP (P less than 0.005), by 14% in ST (P less than 0.05), and by 33% in RB (P less than 0.001), as opposed to untreated rats; return of AsAc toward baseline levels was negligible 24 hours after d-A withdrawal. The above d-A treatment schedule significantly increased (P 0.05) the rate of CAR in the shuttle-box test. AsAc levels resulted also significantly higher (P less than 0.001) in HYP (+81%) and in RB (+46%) at the end of the test; the AsAc level increase was negligible in ST. Twenty-four hours later, AsAc levels were still significantly higher in RB, but returned toward baseline level in HYP. Again, no correlation was found between CAR rate and regional brain AsAc levels. These results demonstrate that d-A is able to increase regional brain AsAc levels both in control and in tested rats. Since it is well known that systemic administration of AsAc antagonizes some d-A behavioral effects, it is suggested, as a working hypothesis, that the d-A CNS stimulating effect may cause a recruitment of endogenous AsAc, whose task could be a negative neuromodulatory action on the overall effect of d-A on neuronal activity.

Animals↗
PubMed1988

Ouabain-insensitive transintestinal transport in the rat jejunum incubated in vitro.

The jejunal tract of rat intestine, everted and incubated in vitro at 28 degrees C for 2 hr in Krebs-Ringer bicarbonate solution, was used to test the existence of a ouabain-insensitive sodium pump. Cell water, Na, and K together with Na, fluid, K, and lactate transported into the serosal compartment were determined and, under control conditions, the tested parameters were found constant in time. By blocking the Na-K pump with 20 mM ouabain in the serosal compartment, the enterocyte lost K and gained Na, but the cell volume did not vary. Moreover, the transport of Na, fluid, and lactate, although lower, was constant for 2 hr. When ethacrynate was added or when the ATP supply was blocked by adding 2,4-dinitrophenol plus iodoacetate, the cell swelled and the transport of Na and fluid stopped. These results are interpreted as suggesting the existence of a ouabain-insensitive Na pump, in addition to the well-known Na-K pump.

2,4-Dinitrophenol↗
PubMed1988

Mechanisms of Na transport at the basolateral pole of rat enterocyte.

Basolateral membranes isolated from rat jejunal enterocytes and enriched 14 times were found present as unsealed and sealed right side out (RSO) or inside out (IO) vesicles in the ratio 2:2:1. Entrance of 1 mM Na (JNa) into basolateral membrane vesicles was measured in the presence and in the absence of 5 mM ATP by a rapid filtration technique, under different experimental conditions. JNa across the basolateral membrane is cis-inhibited by K, transstimulated by K and further stimulated by ATP (activation of the Na pump). Both K- and ATP-positive effects are also obtained by other cations: the relative stimulation sequence is K greater than Rb = NH4 greater than Cs. The ATP effect can be suppressed by vanadate and strophanthidin; moreover the K effect on JNa is not influenced by blocking the mechanism of the Na pump with ouabain, strophanthidin and adenosine 5'-[beta,gamma-imido]triphosphate. The transmembrane potential does not influence the K-stimulated JNa. In addition to the Na pump this study demonstrates the existence of an exchange mechanism between Na and K, which seems to be different from the Na pump. There appears to be no Na-K cotransport.

Adenosine Triphosphatases↗
PubMed1987

High-resolution 1H NMR study of the solution structure of alamethicin.

A 1H NMR study of the peptide alamethicin, which forms voltage-gated ion channels in membranes, is described. The molecule was studied in methanol as a function of temperature and pH. A complete assignment of the spectra is given, including several stereospecific assignments. Alamethicin was found to have a structure substantially similar to the crystal although, in solution, the C-terminal dipeptide adopts a somewhat extended conformation. The overall conformation was insensitive to the ionization of the side chain of the only ionizable group, Glu-18.

Alamethicin↗
PubMed1987

Effects of semistarvation on transintestinal D-glucose transport and D-glucose uptake in brush border and basolateral membranes of rat enterocytes.

The present work shows that semistarvation (8-10 g of food for 10 days) increases net D-glucose, Na+ and water transport in the everted and perfused rat jejunum. A linear and positive correlation between cell sugar concentration and transport was found in control and semistarved rats, but the phenomenon was more relevant only in semistarved animals. Membrane vesicle experiments showed that semistarvation increases sugar overshoot only in brush border membrane vesicles, while this situation does not occur in basolateral membrane vesicles. The effect of partial food deprivation seems to enhance net sugar transport by increasing sugar entry across the apical membrane of enterocytes.

Animals↗
PubMed1987

Neurochemical and behavioural changes induced by ascorbic acid and d-amphetamine in the rat.

In male Wistar rats, ascorbic acid (AA) (1 gr/kg i.p.) significantly (P less than 0.05) decreased the rate of CAR in the shuttle box avoidance test and antagonized the d-amphetamine (d-A) (1 mg/kg s.c.)-induced increase of CAR. Shuttle box test reduced striatal dopamine (DA) levels by about 86% (with a consistent 2-3 fold increase of DOPAC levels). DA levels were greatly reduced also in hypothalamus (HYP) and in hippocampus (HIP). AA further decreased striatal DA but significantly antagonized the reduction of DA levels in HYP and HIP. d-A antagonized the reduction of DA levels in all the above brain regions. Shuttle box test reduced noradrenaline (NA) levels mainly in HIP (-52%) and again d-A showed a significant protective effect in all regions; AA did not interfere with NA level reduction in striatum (ST) and HYP, but antagonized it in HIP. It is concluded that striatal DA system plays an important role in rat operant active avoidance behaviour. AA seems to exert a negative modulatory activity which can be counteracted by d-A.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1987

Xanthogranulomatous pyelonephritis in childhood: report on an unusual case.

A case of localised xanthogranulomatous pyelonephritis (XPN) in a 4-year-old female with an unusual radiological picture is reported. The young girl was suspected to have a liver tumour because of a hypervascularised area found by arteriography in the hepato-diaphragmatic region. Laparotomy disclosed a large mass in the upper pole of the right kidney which was adherent to the liver and to the diaphragm. Excision of the large mass including upper pole of the kidney was carried out. Recovery was uneventful. Pathological examination revealed the XPN disease pattern.

Angiography↗