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Biomedical subjects

G Esposito

Publications and source records attributed to G Esposito.

At least 253 records · Page 14Linked to original sources
PubMed1987

Sodium transport in basolateral membrane vesicles from rat enterocytes.

Basolateral membranes purified from rat jejunal enterocytes and enriched 14 times in (Na, K)-ATPase, are present as unsealed and right side out (RSO) or inside out (IO) vesicles in the ratio 2:2:1, as determined by detergent activation of ATPase activity. Entrance of 1 mM Na 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. Carrier-mediated Na transport across the basolateral membrane can be trans-stimulated and cis-inhibited by K and further stimulated by ATP (activation of the Na pump). The ATP effect can be suppressed by vanadate and strophanthidin and enhanced by bleomycin (19% increase), which positively also acts on (Na, K)-ATPase activity (16% increase). In addition to the Na pump this study demonstrates the existence of a carrier-mediated Na transport trans-stimulated by K. There appears to be no cotransport of Na-K.

Animals↗
PubMed1986

A high resolution 1H NMR study of the solution structure of human epidermal growth factor.

500 MHz 1H NMR studies of human epidermal growth factor are described. The backbone resonances of the 1-48 derivative of hEGF have been assigned using two-dimensional techniques. Analysis of the type and magnitude of the observed sequential nuclear Overhauser effects and the NH-alpha CH spin-spin coupling constants allowed prediction of the secondary structure. Aspects of the tertiary structure are also identified. A pair of antiparallel beta-sheets involving residues 18-23 and 28-34 is a dominant feature of the solution structure.

Chemical Phenomena↗
PubMed1986

Immunological abnormalities in patients with cervical carcinoma.

The cellular immune response of 58 patients affected by cervical cancer was evaluated with the aim of investigating abnormalities in T-cell populations. Subjects were divided into three groups: severe dysplasia or carcinoma in situ, microinvasive carcinoma, and invasive carcinoma. T cells were assessed by a spontaneous rosette formation test with sheep red blood cells and by reactivity with specific monoclonal antibodies of OKT series (OKT4 and OKT8 positive lymphocytes). A significant T-cell depression was observed in all patient groups; the lowest T-cell level was observed in group (b), which revealed an inverted OKT4+/OKT8+ ratio too. The results support the hypothesis that cell-mediated immunity is a key factor in premalignant status and in the early development of cervical cancer.

Adult↗
PubMed1986

Congenital giant diverticulum of the posterior urethra in a 4-year-old boy.

A congenital giant diverticulum of the posterior urethra in a 4-year-old boy is reported. The theories on development of congenital urethral diverticula are considered and the importance of the clinical, radiological, endoscopical and histological examination for the differential diagnosis of the acquired diverticula and enlarged utricle is emphasised. In the majority of diverticula transurethral unroofing is most appropriate. The larger and symptomatic diverticula require open excision and eventually urethral reconstruction. Small asymptomatic diverticula may not require any treatment.

Child, Preschool↗
PubMed1985

Intestinal sugar transport during ageing.

Ageing effects on sugar intestinal transport were studied by using the everted sac and the brush-border membrane vesicle techniques. Four age groups of rats were used: very young, young, adult and old animals. Net transintestinal transport of D-glucose and intracellular sugar accumulation were greater in young than in very young, adult and old rats. Net Na+ transport was high in very young and young animals and then it declined with age. In brush-border membrane vesicle experiments D-glucose overshoot was smaller in the groups of animals where net sugar transport was less. In old rats, however, the overshoot did not occur. Short-circuiting of vesicles with valinomycin showed that the driving forces for sugar accumulation, i.e. the chemical potential gradient of Na+ and the electrical potential gradient, played different roles during ageing. In very young animals the chemical potential gradient seems to be responsible for D-glucose overshoot; in young rats both gradients are important while in adult animals the electrical potential gradient represents the main driving force.

Aging↗
PubMed1985

The basolateral membrane of rat enterocyte: its purification from brush border contamination.

Basolateral membranes obtained by self-orienting Percoll-gradient centrifugation were treated with 5 mM CaCl2 to minimize the cross-contamination by brush border membranes. From marker enzyme-specific activities it was calculated that in this preparation the basolateral/brush border membrane ratio was 22.6. A low L-glucose permeability across basolateral membrane vesicles together with ATP-dependent sodium uptake was observed.

Animals↗
PubMed1985

Age-related changes in rat intestinal transport of D-glucose, sodium, and water.

Experiments were performed with everted sacs of jejunum and ileum and brush-border membrane vesicles from four different age groups of rats: very young, young, adult, and old. The changes with age in several parameters, such as cell electrolyte and D-glucose concentrations, cell volume, net D-glucose, Na+ and water transport, and D-glucose uptake into vesicles, were studied. Differences in transport activities in the four age groups of animals were observed. In the jejunum the greatest transport was found in young rats and less in adult, very young, and old rats. In the ileum, the greatest transport activity was found in very young and young rats, while in adult and old animals transport activity was negligible. The cell volume of the enterocyte was significantly smaller in old rats. Changes in cell electrolytes (increased Na+ and decreased K+) were observed only in the jejunum of old rats. The overshoot of D-glucose in brush-border membrane vesicles varied considerably in the four different age groups of animals. In other words, the capacity for sugar uptake into vesicles is greater in young rats than in very young or adult animals. In old rats there was no overshoot, and a slow linear increase of sugar entry was observed. The results indicate that the changes in D-glucose transport with age might be explained in part by the changes in the amount of sugar that crosses the brush-border membrane of the enterocyte.

Aging↗
PubMed1985

[Congenital cystic adenomatoid malformation of the lung].

Congenital cystic adenomatoid malformation of the lung (CCAM) has been reported with increasing frequency since it was first described in 1949. In a review of the literature by Halloran and co-workers in 1972, 61 cases were reported. After ten years, we collected from the literature 279 cases. The malformation is characterized by a multicystic mass of lung tissue with bronchiolar proliferation and alveolar impairment. The clinical picture of this pulmonary malformation varies with the age at presentation. In the neonatal period the respiratory distress syndrome is often very serious and may require an urgent treatment. In the older infant, the unrecognized disease has more often a chronic course characterized by recurrent respiratory infections and failure to thrive. Sometime, the malformation may be completely silent and be disclosed during a routine examination of the thorax for others reasons. Both types of presentations of the cystic adenomatoid malformation require a surgical therapy and the lobectomy is the treatment of choice. The prognosis following resection in the older patients is generally good, while in the neonatal period the remaining hypoplastic pulmonary tissue may represent a problem in the postoperative ventilatory management. Two cases of congenital cystic adenomatoid malformation observed in a 5 months old and in a 10 months old infants are reported. The clinical, pathologic and radiologic features of this pulmonary malformation are discussed. The hypothesis of a future "in utero" correction of the most severe cases, in order to prevent the pulmonary hypoplasia of the healthy parenchyma, is also suggested.

Abnormalities, Multiple↗
PubMed1985

[Anteposition of the anus. A cause of constipation in children].

Certain forms of severe constipation, unresponsive to medical treatment and classified as "idiopathic", have been thought to be anatomical anomalies due to anterior-displacement of the anus. The difficulty in defecation varies with the anal anomaly: this may range from passing of feces every 3-4 days to sub-occlusion episodes due to obstruction of the rectum from phecaloma and with sign of malnutrition, anemia and hypotrophy. Anatomically the anomaly is characterized by an anterior positioning of the anus which deviates the terminal part of the rectum in a horizontal plane creating a "cul-de-sac" which arrests normal fecal advancement. Fecal stasis in the rectal ampulla leads to an increase in the distensibility of the rectum with loss of the normal stimulus to defecate and contractile activity. Diagnosis is made by physical examination, barium enema (which reveals the rectal "cul-de-sac" and the distension of the colon) and ano-rectal manometry to rule out Hirschsprung diseases. The authors report their experience with 11 cases of anterior displacement of the anus, presenting a simple surgical treatment and the favorable results.

Anal Canal↗
PubMed1984

Influence of ageing on sugar and electrolyte transport in rat jejunum and ileum "in vitro".

In vitro experiments on everted sacs of jejunum and ileum of very young, adult and old rats have shown that intestinal transport activity (D-glucose, Na+ and water transports) decreases with age and that a contemporaneous electrolytes embalance of the enterocyte, occurs. Experiments with brush border membrane vesicles of enterocytes of different ages seem to suggest that the entry mechanism of solutes into the cell is, to same extent, involved.

Aging↗
PubMed1984

Bicarbonate movement across basolateral membrane vesicles from rat jejunum.

The self-orienting Percoll-gradient centrifugation was used to separate basolateral membranes (BLMs) from rat jejunal enterocytes. Bicarbonate uptake into osmotically active BLM vesicles was studied by a rapid filtration technique. The time course of [14C] -labelled bicarbonate uptake was followed for 30 min at 18 degrees C and at pH 8.2. Bicarbonate uptake was fast, not saturable and stimulated by countertransport. This work demonstrates that it is possible to determine bicarbonate flux across BLM vesicles at pH and temperature values close to usual experimental conditions. Together with simple diffusion, bicarbonate would cross the BLM of the enterocyte via a carrier-mediated diffusion process.

Animals↗