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Biomedical subjects

M Moretó

Publications and source records attributed to M Moretó.

At least 37 records · Page 2Linked to original sources
PubMed1997

Hexose transport across the basolateral membrane of the chicken jejunum.

The characteristics of the basolateral transport of D-glucose (D-Glc) and D-fructose (D-Fru) have been studied in membrane vesicles from the jejunum of 5- to 6-wk-old chickens. Uptake of hexoses was measured using a rapid filtration method. The maximal rate of transport (Vmax) for D-Glc was 2.36 nmol x mg(-1) x s(-1) and for D-Fru was 3.79 nmol x mg(-1) x s(-1). The Michaelis constants were 17.3 mmol/l for D-Glc and 40.4 mmol/l for D-Fru. D-Glc inhibited its own transport (Ki = 17.4 mmol/l) and the transport of D-Fru (Ki = 18.7 mmol/l). D-Fru inhibited its own transport (Ki = 38.1 mmol/l) and the transport of D-Glc (Ki = 40.3 mmol/l). The transport of both hexoses was Na+ independent, theophylline and cytochalasin B sensitive, and showed cis-inhibition by structural analogs. In preloaded vesicles, the uptake of D-Fru was trans-stimulated by D-Glc and 2-deoxy-D-glucose. These properties indicate the presence of a low-affinity high-capacity glucose transporter isoform (GLUT-2)-type carrier in the chicken intestine, responsible for moving both D-Glc and D-Fru across the basolateral membrane.

3-O-Methylglucose↗
PubMed1996

L-lysine transport in chicken jejunal brush border membrane vesicles.

The properties of l-lysine transport in chicken jejunum have been studied in brush border membrane vesicles isolated from 6-wk-old birds. l-lysine uptake was found to occur within an osmotically active space with significant binding to the membrane. The vesicles can accumulate l-lysine against a concentration gradient, by a membrane potential-sensitive mechanism. The kinetics of l-lysine transport were described by two saturable processes: first, a high affinity-transport system (KmA = 2.4 +/- 0.7 micromol/L) which recognizes cationic and also neutral amino acids with similar affinity in the presence or absence of Na+ (l-methionine inhibition constant KiA, NaSCN = 21.0 +/- 8.7 micromol/L and KSCN = 55.0 +/- 8. 4 micromol/L); second, a low-affinity transport mechanism (KmB = 164. 0 +/- 13.0 micromol/L) which also recognizes neutral amino acids. This latter system shows a higher affinity in the presence of Na+ (KiB for L-methionine, NaSCN = 1.7 +/- 0.3 and KSCN = 3.4 +/- 0.9 mmol/L). L-lysine influx was significantly reduced with N-ethylmaleimide (0.5 mmol/L) treatment. Accelerative exchange of extravesicular labeled l-lysine was demonstrated in vesicles preloaded with 1 mmol/L l-lysine, l-arginine or l-methionine. Results support the view that l-lysine is transported in the chicken jejunum by two transport systems, A and B, with properties similar to those described for systems b0,+ and y+, respectively.

Animals↗
PubMed1996

Endoscopic injection of ethanolamine as a treatment for achalasia: a first report.

BACKGROUND AND STUDY AIMS: The present study aimed to test the hypothesis that endoscopic sclerotherapy may effectively reduce the occurrence of spasm at the level of the gastric cardia, offering an effective treatment for achalasia. PATIENTS AND METHODS: We prospectively treated 33 achalasia patients by repeated injection of ethanolamine oleate at the cardiac level. Twenty patients (series I) were reassessed after six to nine months, with a mean follow-up of 31.5 months (range 13-54 months) after treatment. In an attempt to avoid stricture formation, the last 13 patients (series II) were then treated on the basis of the need to reduce the number of injections per session and avoid new treatment while inflammatory or ulcerative signs, or both, were present. The series II patients were followed up for a mean of 11 months (range 1.7-21.3 months). RESULTS: Overall, a mean of 3.6 treatments was required, and the result was described as "excellent" or "good" in 31 of the 33 patients after one month. Two patients had a poor response to the treatment, but their condition improved after repeat treatment. After six to nine months, the subjective parameters (dysphagia, regurgitation, bronchopulmonary symptoms) and objective parameters (diameter of the esophagus, scintigraphy, manometry), had improved considerably after the treatment in the series I patients, and this improvement was sustained for more than two years, at least by subjective criteria. Four of the 20 series I patients developed mild or moderate fibrotic strictures, but these were managed successfully by standard 15-20 mm balloon dilation. No additional strictures were recorded in the last thirteen patients treated (series II). None of the patients who were followed up had to undergo surgery due to failure of the treatment. CONCLUSION: Endoscopic sclerotherapy appears to be a very promising alternative to the currently available therapeutic tools for achalasia.

Adult↗
PubMed1996

Kinetics of hexose uptake by the small and large intestine of the chicken.

The kinetic parameters of hexose uptake by the small and large intestine of the chicken have been determined in vitro. Rates of initial influx of alpha-methyl-D-glucoside and L-glucose were measured in everted sleeves of the duodenum, jejunum, ileum, proximal cecum, and rectum. Results show the following. 1) Maximal transport capacity values for alpha-methyl-D-glucoside show that the jejunum is the segment that is best suited for Na(+)-mediated uptake. 2) The calculated apparent Michaelis constant values were (in mmol/l) 11.6 for duodenum, 7.8 for jejunum, 3.5 for ileum, 2.4 for proximal cecum, and 7.1 for rectum. This suggests that, with the exception of the rectum, the affinity of the carrier for alpha-methyl-D-glucoside progressively increases in the distal direction. 3) Diffusion constant values indicate that influx of hexoses by a passive mechanism in the duodenum and proximal cecum is significantly higher than in the other segments. 4) The sum of passive and mediated mechanisms confers to the duodenum and jejunum a high capacity to absorb hexoses. The ileum, proximal cecum, and rectum have a quantitatively minor role, albeit significant, in completing the absorptive function.

Animals↗
PubMed1995

Hexose accumulation by enterocytes from the jejunum and rectum of chickens adapted to high and low NaCl intake.

We have studied the effects of adaptation to low NaCl intakes on hexose transport using suspensions of enterocytes isolated from the jejunum and the rectum of the chicken. Animals (12-13 weeks old) were kept for 11 days on either a high-Na+ (HS) or a low Na+ (LS) diet. On day 11, mean serum aldosterone concentration was 46 pg/ml in HS birds and 236 pg/ml in LS birds. Results of transport studies show that: (1) adaptation to a LS diet reduces the cellular 3-oxymethyl-D-glucose cumulative capacity by 40% in the jejunum and is virtually abolished in the rectum; (2) LS adaptation reduces initial alpha-methyl-D-glucoside influx (1 mmol/l) by 22% in the jejunum and by 54% in the rectum; (3) the influx of the membrane potential sensor tetraphenyl-phosphonium (TPP+) in enterocytes strongly suggests that rectal cells of LS birds are significantly depolarized; (4) the presence of 0.1 mmol/l amiloride increases the capacity of the rectal cells of LS birds to establish a sugar gradient across the membrane; (5) incubation of enterocytes with cytochalasin B increases sugar cumulative capacity of the jejunal cells of both HS and LS birds, and has no effect on the rectal cells of LS birds. We conclude that the effects of LS adaptation on sugar transport may involve a reduction in the membrane electrical potential.

Amiloride↗
PubMed1995

Cell apical surface area in enterocytes from chicken small and large intestine during development.

The absorptive surface of epithelial cells from chicken small and large intestine was studied at the day of hatch (1 d group) and at 2 and 6 wk after hatch. The segments considered were duodenum, jejunum, ileum, cecum (proximal, medial, and distal regions), and rectum. The length, diameter, and density of microvilli as well as cell apical diameter were measured in tip-villous enterocytes by transmission electron microscopy. The results obtained showed that during development: 1) microvillus length remained constant in duodenum and jejunum and decreased in the other segments; 2) microvillus diameter increased only in the jejunum and the rectum; 3) microvillus density increased in duodenum, ileum, distal cecum, and rectum (especially from 1 d to 2 wk) and did not change in the other segments; 4) cell apical diameter did not change; 5) apical surface area increased both in the duodenum (2nd to 6th wk) and in the jejunum (1 d to 2 wk) but did not change in the ileum. In the proximal-medial cecum and in the rectum there was a decrease in apical surface, whereas no changes were observed in distal cecum. Results indicated that microvillus length and density are the variables that best explain the changes observed in apical surface that occurred during development.

Animals↗
PubMed1994

Hexose transport across the apical and basolateral membrane of enterocytes from different regions of the chicken intestine.

The properties of hexose transport across the apical and basolateral membranes of chicken enterocytes have been studied in the small and large intestine. Results show that (a) isolated epithelial cells from all segments except the coprodeum can accumulate 3-O-methylglucose (Glc3Me) against a concentration gradient, by a Na(+)-dependent and phloridizin-sensitive mechanism. (b) The cell cumulative capacity for Glc3Me (control/phloridizin-incubated cells) is lower in the small intestine than in the large intestine (rectum = proximal caecum = ileum > jejunum > duodenum). (c) Theophylline enhances the cell Glc3Me cumulative capacity 2.9-fold in the duodenum and 2.4-fold in the jejunum but has no effect in the other segments studied. (d) Analysis of sugar uptake indicates that net hexose influx rates decrease from proximal to distal regions: jejunum > duodenum > ileum = proximal caecum = rectum for the apical transport system (alpha-methyl glucoside as substrate and phloridizin as inhibitor) and duodenum > jejunum > ileum = proximal caecum = rectum for the basolateral system (2-deoxyglucose; theophylline). (e) The duodenum and the jejunum show high apical and basolateral hexose transport rates, which confer a significant capacity for sugar absorption on the proximal intestine. More distal regions, including the ileum, the proximal caecum and the rectum, have transport systems analogous to those of the proximal intestine that keep a considerable potential capability to recover hexoses from the lumen.

3-O-Methylglucose↗
PubMed1994

Combined (short-term plus longterm) sclerotherapy v short-term only sclerotherapy: a randomised prospective trial.

Short term sclerotherapy (by injection(s) around the bleeding point) is used for immediate control of massive haemorrhage from oesophagogastric varices. The usefulness of longterm sclerotherapy once short term sclerotherapy has been successfully carried out was assessed. Two treatment groups were studied: 50 patients were treated by 'combined' (short term followed by longterm) sclerotherapy; 56 patients were treated by short term sclerotherapy only. Patients included in the second group were treated by short term sclerotherapy only if a variceal rebleeding was present. The overall cumulative proportion of patients rebleeding was not significantly different in either group. Combined sclerotherapy patients, however, experienced less episodes of variceal haemorrhage and the source of haemorrhage was different (p < 0.002). Combined sclerotherapy was more efficient in preventing bleeding from oesophageal bleeding points but not those arising from a junctional source (p < 0.05). A greater incidence of oesophageal rebleeding was found in those patients whose first source of bleeding was oesophageal (p < 0.05). No significant difference was detected in survival expectancy between either group. In conclusion, after short term sclerotherapy is carried out successfully, those patients with bleeding from variceal bleeding points located on oesophageal mucosa should benefit most from a longterm sclerotherapy programme.

Esophageal and Gastric Varices↗
PubMed1994

[Cholestasis caused by Fasciola hepatica].

Human infestation with Fasciola hepatica is observed occasionally. Cholestasis due to parasitic obstruction of the common duct is an infrequent complication. A case of fascioliasis is described in a 56 year-old male with symptoms of biliary colic and biochemical cholestasis. The diagnosis was based on the indirect hemagglutination test and the evidence of Fasciola hepatica in the extrahepatic biliary tract shown by ultrasound and ERCP. The patient presented an acute pancreatic reaction during an attempt at therapeutic endoscopic sphincterotomy. Medical treatment was initiated then with Bithionol. Cholestasis as well as the parasitosis were eliminated. Recovery was demonstrated by the normality of the titres of hemagglutination and of the biliary tract by ERCP.

Cholestasis↗
PubMed1993

Idiopathic acute esophageal necrosis: not necessarily a terminal event.

Idiopathic acute esophageal necrosis (AEN) has been considered a rare event, usually having an ischemic origin. Primarily cases from autopsy studies have been reported. This report deals with 10 such cases which were diagnosed among some 80,000 esophago-gastroscopies performed during a 16-year period. Nine patients recovered and were discharged from the hospital. The esophageal lesions presented as a demarcated, black discoloration which usually evolved to a picture suggestive of unspecific esophagitis. Histology invariably revealed diffuse and conspicuous necrosis involving the mucosa, submucosa and, frequently, muscular layers. In 2 cases, esophageal stenosis developed and, in one case, a full-thickness necrosis made surgery with colon interposition mandatory. Hyperglycemia, hypoxia, carcinoma and ischemic phenomena were found as associated conditions. Gastroduodenal, acute ulcerative disease was present in four patients. From this experience, it is concluded that AEN is not necessarily a terminal phenomenon, notwithstanding that it is usually associated with pre-existent serious illness. Nevertheless, its etiology remains unknown.

Acute Disease↗
PubMed1992

Endoscopic local injection of ethanolamine oleate and thrombin as an effective treatment for bleeding duodenal ulcer: a controlled trial.

The injection of a mixture of ethanolamine oleate and thrombin as an effective treatment for bleeding duodenal ulcer was evaluated in 38 patients entered in a randomised prospective controlled trial. After a one week observation period, 1/19 (5.3%) treated patients and 11/19 (57.9%) control patients had suffered further bleeding (p less than 0.005; CI = 22%-74%). Emergency surgery was required in 1/19 in the treated group compared with 8/19 in the untreated group (CI = 13%-61%; p less than 0.05). The mean (SD) transfusion requirement in the treated group was 1.9 (0.5) U blood compared with 5.3 (0.7) U in the control group. No significant differences related to mortality were detected. In conclusion, local injection therapy is an effective means of haemostasis in patients with bleeding duodenal ulcer who are at risk of further bleeding.

Drug Combinations↗
PubMed1992

HgCl2 inhibition of Na-independent L-proline transport in chicken proximal cecum.

The proximal cecum of 5- and 13-wk-old chickens takes up L-proline (Pro) by two saturable pathways that differ in their requirement of Na+. The kinetic properties of Pro influx in cecal segments incubated in Na(+)-free conditions, have been studied and the effect of HgCl2 on the uptake process has been tested. Experiments were carried out using an in vitro everted-sleeve method. Kinetic parameters were estimated by nonlinear regression analysis. One min Pro fluxes in tissues incubated in presence of HgCl2 fit a straight line, indicating that a Na-independent saturable component was inhibited. Estimated Kd* values are the same in 5- and 13-wk-old chickens, 0.023 +/- 0.001 and 0.027 +/- 0.001 microliters.mg-1 x min-1, respectively. HgCl2-sensitive fluxes fit a Michaelis hyperbola, with similar Km* values, 4.85 +/- 1.86 (5-wk) and 9.47 +/- 3.0 (13-wk) mmol/l. However, Vmax* in 5-wk chickens (0.662 +/- 0.053 nmol.mg-1 x min-1) is higher than in 13-wk birds (0.420 +/- 0.039), in accordance with previous results. The present data give further support to the existence of a Na-independent L-proline carrier in the chicken proximal cecum which is inhibitable by HgCl2.

Age Factors↗
PubMed1991

Morphological study of the caecal epithelium of the chicken (Gallus gallus domesticus L.).

1. The structure of the chicken caecal epithelium has been investigated at macroscopic and microscopic levels (scanning and transmission electron microscopy). 2. Morphological data distinguish three regions in the caecum: proximal, with well developed villi, but smaller and less numerous than those present at mid-jejunum; medial, with longitudinal folds and small villi, and distal, with longitudinal and transverse folds and small villi similar to those of the medial region. 3. Microvilli of enterocytes from the tip of the villus of the proximal caecum are shorter and thinner than jejunal microvilli; microvilli of medial and distal regions are poorly developed. 4. There is a decrease in microvillus surface area along the villus axis as a result of the progressive decrease of microvillus length from the tip of the villus to the crypt, both in the proximal caecum and jejunum. In tip of the villus, the amplification of apical surface due to microvilli is 24, 12.7 and 14 times in proximal, medial and distal caecum, respectively, while in the jejunum the amplification factor is 33.1. 5. The higher development of proximal caecal apical surface supports the view that this region is better adapted for the absorption of nutrients that the other caecal regions.

Animals↗
PubMed1991

Transport of L-proline and alpha-methyl-D-glucoside by chicken proximal cecum during development.

We examined the characteristics of amino acid and sugar absorption by the proximal cecum (PC) of chickens during posthatch development. Rates of absorption of L-proline (Pro) and alpha-methyl-D-glucoside (MG) were measured at 2 days, 5 wk, and 13 wk after hatch with an in vitro everted-sleeve method. For each age, pieces of PC and midjejunum were incubated in solutions containing 0.1-50 mM Pro or MG, and the active and passive components of Pro and MG absorption were determined. Five conclusions may be stated. 1) There are two carrier-mediated transport systems for Pro in the PC: a higher capacity Na(+)-dependent system (Vmax between 1.6 and 3.2 nmol.mg-1.min-1), and a lower capacity Na(+)-independent system (Vmax 0.3-0.8 nmol.mg-1.min-1). 2) Whereas both Pro transport systems are present in the PC at 5 and 13 wk, only the Na(+)-dependent system was found at 2 days. Although rates of transport per milligram tissue by the Na(+)-dependent system fell during development, when rates were normalized to nominal surface area, Vmax was significantly higher in the 5-wk-old group than in the other groups. 3) MG transport is by a Na(+)-dependent system. Vmax values (nmol.mg-1.min-1) were 0.32 (2 days), less than 0.43 (5 wk), and = 0.55 (13 wk). These differences were not affected by normalization to surface area. 4) Because at physiological concentrations passive influx of Pro and MG would be negligible, absorption of amino acids and sugars by the PC would be dependent on the presence of carrier-mediated systems.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1990

Endoscopic incision as an alternative to bougienage in the treatment of peptic esophageal stricture.

With the aim of suggesting incision of peptic esophageal strictures, as an alternative to bougienage, we report the results of the first 20 patients so treated. We included as candidates for this treatment all those patients with moderate or severe dysphagia in whom a stricture of the distal esophagus was confirmed on esophagoscopy that could not be negotiated despite continuous and vigorous pressure with the tip of the fiberscope. On the basis of radiological films, the minimum diameter of the stenotic ring (+/- SD) was 4.4 +/- 2.2 mm, increasing up to 10.05 +/- 1.5 mm once the endoscopic procedure was made. Dysphagia was initially relieved in all the cases. Four patients had recurrence within a few days after the incision. Later, another 4 patients had recurrence. Finally, a further 4 cases were lost by non-compliance. The remaining 8 patients who underwent a 6-months' follow-up did not show a later tendency to re-stenosis. In total, 5 patients were surgically treated for hiatal hernia. One case of emphysema in the mediastinum was noted and treated conservatively. We conclude that endoscopic incision is an alternative to esophageal dilatation as initial treatment for peptic esophageal stricture, despite the fact that a significant number of patients will require additional surgical correction for gastro-esophageal reflux.

Dilatation↗
PubMed1990

Influence of setting-up time, temperature of incubation and age on the transmural potential difference across chicken rectum.

The effects of different experimental conditions on the in vitro transmural potential difference (PD) have been studied in the chicken rectum by the Ussing and Zerahn technique. Results have been analyzed with a statistical method to reveal the contribution of different controlled variables to the response, as well as the possible contribution of interactions between them. The variables considered were: age, setting-up time, temperature of the incubation medium and time elapsed from the beginning of incubation. It can be concluded that a) PD increases when temperature rises from 31 degrees C to 37 degrees C and when age increases from 71 to 123 days; b) Changes in PD during incubation depend on the temperature of incubation medium; c) The influence of age on PD depends on the temperature of the incubation medium and on the time required to set-up the preparation; d) PD is inversely co-related with setting-up times ranging from 3.5 to 7.5 min.

Aging↗