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R Ferrer

Publications and source records attributed to R Ferrer.

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

Transport of L-valine by the chicken caecum.

1. We have studied L-valine transport by the caecal segments of 6- to 8-week-old chickens. Isolated enterocytes from the proximal caecum incubated with 0.1 mM L-valine can accumulate the substrate against a concentration gradient. After 50 min incubation, the intracellular L-valine concentration reached 0.53 mM, a value higher than that observed in enterocytes from the jejunum (0.34 mM; P< 0.01). 2. Enterocytes from the medial and distal caccal regions are unable to transport L-valine uphill (cell concentration: 0.1 mM). 3. Amino acid accumulation by proximal caecal cells was Na+ -dependent and was inhibited by ouabain and 2,4-dinitrophenol. L-methionine inhibits L-valine uptake and a 2.5 mM concentration abolishes the capacity of enterocytes to accumulate the substrate. 4. The high accumulation ratios shown by the proximal caecum for L-valine suggest a role for this intestinal segment in the absorption of neutral amino acids present in the caecal chamber.

2,4-Dinitrophenol↗
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↗
PubMed1995

Follow-up of patients resected for gastric cancer.

In this study we used a cost-outcome analysis to evaluate our follow-up protocol for patients who had been resected for gastric cancer. We designed a descriptive cross-sectional trial through consecutive sampling of patients who had undergone resection of gastric carcinoma and were followed in our outpatient department during 1991. Serological (CEA) and or imaging procedures were pathologic at least two months prior to the onset of symptoms in 33% of recurrences. No significant correlation was found between serum CEA levels and CEA tumor tissue staining in patients who recurred. Only 17% of patients who relapsed underwent further treatment (surgery and chemotherapy) with no improvement found in terms of survival. The overall cost per year has been estimated at US$ 6118. Our results show that serological levels of CEA and available imaging techniques for routine follow-up provide little advantage in diagnosing gastric cancer recurrence over clinical surveillance alone.

Adenocarcinoma↗
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↗
PubMed1995

[Malignant melanoma of the nasal cavity: a case report].

Mucosal malignant Melanomas have worse prognosis than cutaneous melanoma. Elective treatment is surgery, which eradicates the tumor only in a restricted number of cases. The most frequent cause of treatment's failure is recurrence or local persistence of the disease.

Female↗
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↗
PubMed1993

[The physician-patient relation through a Balint group].

OBJECTIVE: To evaluate by means of a contents analysis a Balint Group (BG) after 7 years in operation, to find which type of patients are most disturbing for the General Practitioner and to analyse the sort of feelings they provoke. DESIGN: A retrospective descriptive study which uses qualitative analysis methodology. SETTING: The BG under analysis was created in the heart of the Catalan Society of Family and Community Medicine in 1984. PATIENTS: 21 sessions were analysed, covering 18 patients. INTERVENTIONS: The variables studied were: the motives for presentation, the sort of patient presenting and the doctor's feeling towards them. MEASUREMENTS AND MAIN RESULTS: Two types of patients stood out: those with somatization disorders and those with a very poor prognosis. The first (12 out of 18) unsettled the professional and caused him/her to lose grip on his/her role. The GP often trivialised their requests or thought they were pretending. Those sessions analysed where patients had a poor prognosis made clear the high degree of empathy shown by the doctor. Questions were raised as to how to tackle the illness both with the patient and his/her family. Feelings of distress, fear, anguish-exhaustion-impotence and rejection-aggression of the doctor towards particular patients were analysed. CONCLUSIONS: The questioning of the doctor's social role or professional identity by particular patients makes it difficult for him/her to maintain a long-term therapeutic relationship with them. The BG was useful for the participants, because of the group dynamic and also because they found out the possibilities and limitations of their treatment.

Adult↗
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

[Incorporation of transferrin into the erythron in anemic and polycythemic conditions].

A ferrokinetic study was performed in 79 patients, 25 with absolute polycythaemia, 19 with relative polycythaemia and 35 presenting anaemia of different aetiology. The incorporation of transferrin into the erythron (ITE) was estimated on each case. The mean ITE values found in absolute primary and secondary polycythaemia and in secondary polycythaemia were, respectively, 281 +/- 85, 181 +/- 99 and 74 +/- 19 mumol/L tb/d (i.e., micromoles per litre of total blood per day). The mean ITE in iron deficiency anaemia was 110 +/- 43 mumol/L tb/d, in haemolytic anaemia this was 274 +/- 151 mumol/L tb/d, and in patients with myelodysplastic syndromes such values was 116 +/- 49 mumol/L tb/d. Significant differences were found for each group of patients with respect to a normal control group. Such findings are in accordance with the pathophysiology of the different pathologies studied. The values found in haemolytic anaemia and myelodysplastic syndromes are similar to those reported by others. The results of this study stress the advantages of evaluating the erythropoietic activity of the bone marrow by means of the ITE.

Adult↗
PubMed1990

Modulation of the frequency of glucose-dependent bursts of electrical activity by HCO3/CO2 in rodent pancreatic B-cells: experimental and theoretical results.

The burst pattern of electrical activity recorded from pancreatic B-cells in response to 11 mM glucose shows a large islet to islet variability. The relationship between burst frequency and glucose sensing (the threshold for electrical activity and the graded increase in electrical response to glucose, i.e. active phase %) has not been investigated within the same islet. In this work, we show that low HCO3 (5 mM) Hepes buffered solutions reversibly reduce the frequency of bursts compared to control (25 mM) HCO3 buffered solutions in the same islet. There was no change in the threshold or active phase (%). Using the mathematical model of Sherman et al. 1988, we explored mechanisms for a change in frequency independent of a change in active phase (%). Increased exchangeable calcium pool size and increased cell to cell coupling were the two theoretical treatments which could reproduce the experimental data. We conclude that burst frequency can be modulated independent of the active phase and that alteration of a calcium pool size best fits the experimental data.

Animals↗
PubMed1990

[The effect of the day of parturition in the technological cycle of maternity on the morbidity of diarrhea in lactating piglets].

The study investigated the frequency of piglet diarrhoea from birth to weaning (33rd day) in a farrowing pigsty with 3 rows of boxes during 7 rearing cycles with 240 piglets each, always related to the day of birth in connection with the onset of the cycle. 3 groups were differentiated according to the day of birth: 3 and 4, 5, 6 and 7, based on the disposition of the sow. Also investigated was the position of the litters in the middle or one of the marginal rows of boxes of the pigsty. The germ density of the air during 2 cycles each of the rainy and dry seasons was investigated in the empty pigsty as well as after the 6th day of occupation by means of sedimentation in endo agar. A significant influence was found of the day birth (p less than 0.05) and of the interaction of row of boxes and day of birth (p less than 0.05) as well as the row of boxes and season (p less than 0.05) on the morbidity and mortality due to piglet diarrhoea. The higher levels occurred in the groups of animals born later and housed in the central row of boxes. The number of units forming colonies increased significantly (p less than 0.05) in 10 cm2/min samples on endo agar from the 0th to the 6th day of the cycle and reached 100% of the samples from which also E. coli K 88 was isolated.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Mortality by crushing in domestic pigs: study of the causes and their relationship to the time and the month of the year in the climatic conditions of Cuba].

In the course of 3 years a complex of 25,000 pigs were investigated once per week for the dead among the 398 sucking piglets, and in the case of losses due to crushing to death the type of lesions and the connection with diseases was investigated. Of the piglets investigated, 88 were crushed to death (21.2%), among them 65 (73.8%) diseased--mainly infected by coli bacilli (60 = 68.2%)--and 23 (5.8%) healthy animals. The losses due to crushing to death were highest in January and differed from all other months of the year (p less than 0.05). Another peak of losses in July was only significant (p less than 0.05) as compared with the values of April and November. January and July also exhibited the highest proportion of coli-infected piglets. The most frequent lesions were edema and cyanosis of the skin, of the mucous membrane, and the hypodermic tissue, haemothorax and haemoperitonaeum, liver cracks, lung cracks, kidney cracks, stomach cracks, large intestine cracks, and multiple fractures of the ribs and of the skull. It is concluded that the losses due to crushing to death can be related to the decrease in vitality of the piglets due to diseases, caused in winter by decreased vitality and in summer by pressure caused by coli infection.

Animals↗