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Biomedical subjects

M Moretó

Publications and source records attributed to M Moretó.

At least 55 records · Page 3Linked to original sources
PubMed1989

Sugar and amino acid transport properties of the chicken ceca.

Chickens have two well-developed ceca, with an epithelium that is histologically and functionally heterogeneous. The proximal region, close to the ileorectal junction, has well-developed villi and microvilli and is able to transport sugars and amino acids against a concentration gradient, by mechanisms virtually identical to those described for the small intestine. The medial-distal region does not have true villi but has mounds and ridges, and it cannot transport either sugars or amino acids in the adult bird. In newborn chicks, the whole cecum can accumulate and transport sugars, but this property is soon restricted to the proximal region. The medial cecum, however, retains some transport capacity until the 8th week after the hatch. Ceca are thus well suited for sugar and amino acid absorption. Their contribution to the overall nutrient absorption is, however, limited, because the absorbing epithelium is exposed to the intestinal contents only during the filling and emptying of the cecal segments.

Amino Acids↗
PubMed1988

Diagnostic yield and endoscopic patterns of laparoscopy in the diagnosis of granulomatous hepatitis.

In reviewing 54 cases of granulomatous hepatitis (GH) diagnosed among 2,620 laparoscopies, we have been able to classify the capsular GH changes into five patterns: Macular, exudative, pinpoint, granular and cord-like. The exudative pattern was the most frequent one, and predominated in brucellosis. The granular pattern was most common in tuberculosis. Furthermore, 35 additional cases, in whom a laparoscopic diagnosis of GH was not confirmed by liver biopsy, showed a trend to a final diagnosis consistent with multifocal diseases, whenever laparoscopic pictures were similar to the patterns described herein. We speculate with the limits associated with the use of only a single biopsy sample. We conclude that laparoscopy permits the establishment of a tentative diagnosis of GH, which could provide us with valuable information about the usefulness of obtaining multiple hepatic biopsies.

Endoscopy↗
PubMed1988

A randomized trial of tamponade or sclerotherapy as immediate treatment for bleeding esophageal varices.

Sengstaken-Blakemore tamponade is used for the initial control of bleeding esophageal varices (BEV), although it is known to be potentially dangerous. Sclerotherapy has been shown to be effective in the treatment of BEV. This trial has been designed to evaluate comparatively the effectiveness of both procedures in the initial control of the hemorrhage. Forty-three patients with BEV were included in the trial. Twenty patients (group SB) were treated by tamponade. Twenty-three patients (group ST) were treated by sclerotherapy by means of a simple technique. During the first 24 hours, hemostasis was obtained in 16 of the SB patients and in all 23 of the ST patients (p less than 0.05). At seven days, nine SB patients and 19 ST patients were free of hemorrhagic relapse (p less than 0.05). By stratifying in relation to hepatic failure, the difference was greater (p less than 0.005) if patients with Child's A classification were excluded. It is concluded that sclerotherapy should be undertaken in almost every instance at the same moment that diagnosis is made, bypassing the intermediate step of tamponade.

Balloon Occlusion↗
PubMed1987

Relation between alpha-methyl-D-glucoside influx and brush border surface area in enterocytes from chicken cecum and jejunum.

We have investigated the possible relation between the phloridzin-sensitive influx of alpha-methyl-D-glucoside (concentration 5 mmol/l) and the brush border surface area, in chicken isolated enterocytes. The intestinal regions studied were: jejunum and proximal cecum (both with high affinity sugar transport sites), medial cecum (with a low affinity transport system) and distal cecum (which lacks any transport ability). Cell apical surface measured by electron microscopy gave the following results; jejunal cells (0.41 micron 2) greater than proximal cecal cells (0.23 micron 2) greater than medial cecal cells (0.15 micron 2) = distal cecal cells (0.14 micron 2). This parameter is mainly determined by the length of microvilli. Sugar influx studies showed that the concentration of the substrate in cell water (in mmol/l) was jejunum (7.1) greater than proximal cecum (2.9) greater than medial cecum (1.7) greater than distal cecum (not different from zero). The decline in influx rate from proximal to distal cecum may be explained both by changes in surface and by the different carriers involved (different Km). Results of sugar concentration in the distal cecal cells do not correlate with the other segments studied since the substrate enters in these cells by a passive process. It is concluded that the degree of development of microvilli should be taken into account when estimating nutrient transport rates in different intestinal segments.

Animals↗
PubMed1987

Efficacy of monopolar electrocoagulation in the treatment of bleeding gastric ulcer: a controlled trial.

With the aim of evaluating, in a controlled prospective fashion, the efficacy of monopolar electrocoagulation in the emergency treatment of bleeding gastric and stomal ulcers, 37 patients were studied: 16 were electrocoagulated (EC group) while the remaining 21 were treated by conventional methods (control group). The hemorrhage recurred in only one of the 16 patients belonging to the EC group, but in 11 of the 21 control patients (p less than 0.0005). Transfusion requirements were also reduced in the EC group (p less than 0.05), with no significant difference in relation to mortality. Stratifying the results according to hemorrhagic activity, electrocoagulation should be clearly effective in those patients with spurting hemorrhage, taking into account several limitations: deep ulcers bearing gross vessels, and lack of cooperation by the patient. Prophylactic treatment of the bleeding ulcer with a visible non-spurting vessel may be indicated whenever we make a proper selection of the patients with a greater possibility of hemorrhagic recurrence.

Adult↗
PubMed1986

Hexose transport by chicken cecum during development.

Hexose accumulation during development has been studied in tissue slices from chicken cecum. The age of birds ranged from 0 to 7 weeks after hatch. Ceca were divided into six portions according to their situation either proximal (PC), medial (MC) or distal (DC) to the ileocecal junction. In 0-day-old chicks all segments can accumulate 3-O-methyl-D-glucose (0.5 mmol/l) against a concentration gradient through a phloridzin-sensitive mechanism. Cumulative capacity is lower in DC than in PC and declines with development. Distal segments lose sugar transport ability 1-2 days after hatch whereas the medial region retains some concentrative ability in older birds. In 7-week chickens, PC slices have a similar cumulative ability to that of jejunum (yolk sac region). Kinetic studies showed that in PC the apparent Km for phloridzin-sensitive transport was half that in 1-day- than in 7-week-old birds; apparent Vm increased by 50% in this time range. The ability to transport sugars by the cecum was further confirmed in isolated enterocytes from 5- to 7-week-old chickens using alpha-methyl-D-glucoside (0.1 mmol/l) as substrate. Cell sugar concentration was greater in PC than in jejunal cells and jejunal greater than MC enterocytes. Sugar present in cells from DC was the same as in phloridzin-treated cells. It is concluded that cecal epithelium may play a significant role in the absorption of sugars during development.

3-O-Methylglucose↗
PubMed1986

Characteristics of the chicken proximal cecum hexose transport system.

The properties of the sugar transport system present in chicken proximal cecum have been studied and compared to the jejunal transport system. Experiments were carried out in isolated enterocytes from 5- to 7-weak-old birds. Results show that: (1) Cecal cells are capable of high sugar transport rates by a phloridzin-sensitive mechanism. After 60 min incubation, the accumulation ratio (control/phloridzin-incubated cells) for 0.1 mmol/l alpha-methyl-D-glucoside (alpha-MG) was 43 and that of 3-oxy-methyl-D-glucose (3-OMG) was 25. In jejunal cells, ratios were 37 for alpha-MG and 13 for 3-OMG. The differences found in cumulative capacity of 3-OMG between cecal and jejunal cells suggest that the sodium-independent pathway offers a very small contribution to sugar efflux in the steady-state in the former cells. (2) Lowering external Na+ concentration reduces the steady-state alpha-MG accumulation in cecal cells (as in jejunal cells), indicating that the transport system is Na+-dependent. (3) The process depends on the electrochemical Na+ gradient across the cell membrane since both 2,4-dinitrophenol (0.2 mmol/l) and ouabain (0.25 mmol/l) abolish sugar accumulation. (4) Addition of 10 mmol/l) 3-OMG to the incubation medium markedly reduces the uptake of alpha-MG (concentration: 0.1 mmol/l), indicating that the cecal transport system can be inhibited by analogues of the transported substrate. (5) The specific sugar transport process is a saturable function of alpha-MG concentration, the apparent Km being 1.02 mmol/l and Vm 10.7 mmol/mg cell protein X min.(ABSTRACT TRUNCATED AT 250 WORDS)

3-O-Methylglucose↗
PubMed1986

Transmural potential difference and short circuit current of chicken cecum in vitro.

The electrical parameters of the chicken cecum were studied in vitro, in birds fed a commercial NaCl-rich diet. The statistical analysis of data was carried out using a linear model-based method which enabled standardization of concomitant factors that could mask the interpretation of the results. Transmural potential difference (PD) decreased initially reaching stable values at 50 min between 7.9 and 9.0 mV. Short-circuit current (Isc) was stable during incubation, with lower values in the medial (41.8 microA/cm2) than in the distal (58.1 microA/cm2) region of the cecum. The reduction of Na+ concentration in the incubation medium produced a fall in PD and Isc and both were ouabain and amiloride sensitive. This indicates that the current is largely carried by the net Na+ transport.

Animals↗
PubMed1986

Absorption of 3-oxy-methyl-D-glucose by chicken cecum and jejunum in vivo.

Jejunal and cecal 3-oxy-methyl-D-glucose (3-OMG) absorption was studied in 4- to 8-week-old chickens by an in vivo perfusion technique (perfusion rate 1.5 ml/min). Total and phloridzin-insensitive 3-OMG absorption was tested for lumenal substrate concentrations ranging from 1.25 to 20 mmol/l. The estimated apparent Michaelis constants in jejunum and cecum were 5.1 and 4.0 mmol/l (Lineweaver-Burk method) and 3.2 and 3.1 mmol/l (visual inspection method), respectively. Vmax were similar in both segments with either method, about 0.3 mumol/cm2 X 5 min. Passive permeability coefficients were the same in both regions (about 45 l/cm2 X 5 min X 10(3)). The transport properties of the cecal epithelium in vivo suggest a role of these intestinal segments in the absorption of nutrients originated from digestive processes.

3-O-Methylglucose↗
PubMed1986

Vascular malformations of the stomach and duodenum: an endoscopic classification.

Having reviewed 47 cases of vascular malformations of the stomach and duodenum, we propose an endoscopic classification for these lesions: Pattern I (flat or slightly protruded, bright red lesions with frond-like margin) is the most usual form of presentation. The "telangiectatic form" (pattern II) is an endoscopic variation, with the same clinical and, possibly, pathogenic significance. Submucosal nodular forms (pattern III) are the most difficult to diagnose and treat. Electrocoagulation is the most pertinent treatment.

Acute Disease↗
PubMed1986

Effect of bisacodyl on the uptake of monosaccharides by isolated enterocytes.

Diphenolic laxatives are known to alter nutrient absorption and secretion in the small and large intestine. We have studied the effect of 0.75 mM bisacodyl on sugar transport in isolated chicken intestinal epithelial cells. Results show that (1) bisacodyl inhibits Na+-dependent alpha-methyl-glucoside (alpha-MG) accumulation by 45% after 40-minute incubation. (2) The drug reduces initial (1 minute) alpha-MG influx by 60%. This effect is much lower than that exerted by 0.15 mM phlorizin (90% inhibition). (3) Bisacodyl also reduces Na+-independent sugar flux through the basolateral membrane since initial 2-deoxy-glucose influx is reduced 67% by the drug. The effect of the drug on this pathway is lower than that exerted by theophylline (7.5 mM). The addition of bisacodyl or theophylline (plus 20 microM phlorizin to inhibit the apical sugar transport system) to cells preloaded with 3-oxy-methyl-glucose allowed calculation of the initial sugar efflux rate. This was found to be lower after theophylline addition than after the addition of bisacodyl, thus confirming that bisacodyl exerts an incomplete inhibition of the Na+-independent sugar transport system. It is concluded that the direct effects of bisacodyl on both apical and basolateral sugar transport pathways may explain in part the inhibitory effects of the drug on the intestinal absorption of sugars.

Animals↗
PubMed1986

Preparation and properties of isolated epithelial intestinal cells from chicken cecum and jejunum.

The isolating agents, one enzymatic (hyaluronidase) and two chemical (sodium citrate and EDTA) have been used to search for the best technique to prepare suspensions of viable cells from chicken cecum and jejunum. Viability of enterocytes was assessed in terms of cell membrane integrity (trypan blue exclusion test), metabolic activity (oxygen uptake, lactate production and ATP content) and monosaccharide cumulative capacity. Results show that: In both cecum and jejunum, membrane integrity is better in cells harvested with citrate than those isolated with hyaluronidase or EDTA; The best metabolic status was found in cecal cells isolated with citrate and in jejunal cells obtained with hyaluronidase; The capacity to support alpha-methyl-D-glucoside gradients is highest in the cells harvested with citrate. The citrate-containing isolation medium is thus considered to yield epithelial cell suspensions with the best functional conditions.

Adenosine Triphosphate↗
PubMed1986

Morphological study of chicken cecal and jejunal mucosa during epithelial cell isolation.

Epithelial cells from jejunum and proximal cecum of the chicken were isolated by using a sodium citrate containing medium. Cell dissociation during the isolation process was studied by scanning electron microscopy. Results after 5, 15 and 30 min incubation show a sequential cell detachment from the tip to the lower regions of the villi. Inspection of the cell suspension by scanning and transmission electron microscopy reveals that most cells are enterocytes that retain their characteristic cylindrical shape. The brush border of isolated cells maintains its architecture, while organelles remain intact.

Animals↗
PubMed1985

Retrospective endoscopic analysis of gastric xanthelasma in the non-operated stomach.

To investigate the significance of gastric xanthelasma, a retrospective review of 109 cases with an endoscopic diagnosis of this lesion was undertaken. A predominance in older patients was noted, with a similar distribution in antrum and fornix. In 15 cases (16.6%) they were multiple. They were occasionally associated with gastric erosions. In particular they were associated with chronic gastritis and intestinal metaplasia (48.9%). It is therefore concluded that gastric xanthelasma is not a rare lesion and that it is frequently associated with senile degenerative changes in the gastric mucosa.

Adult↗
PubMed1984

Involvement of cellular cyclic AMP in theophylline-induced sugar accumulation in chicken intestinal epithelial cells.

We have studied the possible involvement of cellular cyclic AMP in theophylline-induced sugar gradient enhancement in isolated chicken enterocytes. Theophylline increases 3-O-methylglucose accumulation 3-fold after 30 min incubation. Exogenous cyclic AMP enhances sugar accumulation by 48%. Adenylyl cyclase inhibitor RMI 12 330A reduces theophylline-induced sugar gradients by 22% and theophylline-induced cyclic AMP levels by 24.5%. At the concentration used, RMI 12 330A has no effect on 3-O-methylglucose accumulation or basal cellular cyclic AMP. Since theophylline has a rapid inhibitory effect on Na+-independent sugar permeability, we conclude that the effects of the drug on sugar gradients are the result of its acting by both direct - surface membrane - and indirect - cyclic AMP mediated - mechanisms. The effect of theophylline and exogenous cyclic AMP on sugar accumulation is independent of external chloride.

3-O-Methylglucose↗
PubMed1984

[Transmural flow of D-galactose in the jejunum of young rats using a new perfusion chamber].

The chamber used allows the simultaneous but separated incubation of two intestinal segments (approximately 4 cm in length) in vitro and is especially suited for its application to studies on young animals. Segments are perfused with the help of a peristaltic pump (6 ml/h) without recycling. D-galactose fluxes across rat jejunum have been studied in everted jejunal segments from 19-21 day-old rats. Transmural fluxes (JmsGal) were determined using four external mucosal galactose concentrations (0.2, 2, 10 and 20 mM). The ratios of passive JmsGal were 1 : 11 : 49.7 : 96.7. Those due to active transport of the substrate were 1 : 7.1 : 14.6 : 18.8, indicating saturation. The active component of total JmsGal fluxes was 80%, 72%, 54% and 44%, respectively. Comparison of transmural galactose fluxes in noneverted segments from 20 day-old (suckling) and 25 day-old rats, showed that there is a marked reduction in both passive and active components of substrate flux across the intestine at the time of weaning.

Animals↗
PubMed1982

A pattern for gastric emptying in mice.

Gastric emptying was studied in CD-1 mice weighing 15-30 g. Mice were fed a nonabsorbable test meal consisting of radioactive barium sulfate suspended in 1.5% methylcellulose. The amount of test meal remaining in the stomach was determined 1, 2, 5, and 10 min after the administration. The initial rates of emptying were significantly higher in the groups weighing 15-20 g body wt. In all groups, 50% of the radioactivity administered was emptied in less than 5 min. The gastric emptying figures obtained were adjusted to three general equations: exponential, hyperbolic, and parabolic. The best correlation coefficients were obtained with the parabola, although this pattern of emptying is not completely satisfactory because it has a minimum before the 10th min. The comparison of the exponential and hyperbolic patterns, in terms of both the correlation coefficients and the "starting indexes," showed that the hyperbola describes the data more closely. No sex differences were observed.

Animals↗