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Biomedical subjects

R Nieto

Publications and source records attributed to R Nieto.

At least 19 recordsLinked to original sources
PubMed2006

Usefulness of duodenal biopsy during routine upper gastrointestinal endoscopy for diagnosis of celiac disease.

AIM: To describe the trend in duodenal biopsy performance during routine upper gastrointestinal endoscopy in an adult Spanish population, and to analyze its value for the diagnosis of celiac disease in clinical practice. METHODS: A 15 year-trend (1990 to 2004) in duodenal biopsy performed when undertaking upper gastrointestinal endoscopy was studied. We analysed the prevalence of celiac disease in the overall group, and in the subgroups with anaemia and/or chronic diarrhoea. RESULTS: Duodenal biopsy was performed in 1033 of 13 678 upper gastrointestinal endoscopies (7.6%); an increase in the use of such was observed over the study period (1.9% in 1990-1994, 5% in 1995-1999 and 12.8% in 2000-2004). Celiac disease was diagnosed in 22 patients (2.2%), this being more frequent in women than in men (3% and 1% respectively). Fourteen out of 514 (2.7%) patients with anaemia, 12 out of 141 (8.5%) with chronic diarrhoea and 8 out of 42 (19%) with anaemia plus chronic diarrhoea had celiac disease. A classical clinical presentation was observed in 55% of the cases, 23% of the patients had associated dermatitis herpetiformis and 64% presented anaemia; 9% were diagnosed by familial screening and 5% by cryptogenetic hypertransaminasaemia. CONCLUSION: Duodenal biopsy undertaken during routine upper gastrointestinal endoscopy in adults, has been gradually incorporated into clinical practice, and is a useful tool for the diagnosis of celiac disease in high risk groups such as those with anaemia and/or chronic diarrhoea.

Adult↗
PubMed2006

Differences in whole-body protein turnover between Iberian and Landrace pigs fed adequate or lysine-deficient diets.

The capacity for protein deposition in Iberian pigs is lower than in modern (e.g., Landrace) pig breeds, and the reasons for this remain unknown. The hypothesis tested in this work is that under similar nutritional and physiological conditions, whole-body protein turnover as well as the protein synthesis to protein deposition ratio differs between Iberian and Landrace breeds, resulting in dissimilar protein deposition rates. As a main objective, these variables were compared at different protein and Lys intakes in growing gilts. The study examined the effect of Lys deficiency because this is the prevalent condition during the fattening period of the Iberian pig in the Mediterranean forest, where the main feed source is oak acorn, which provides approximately one-third of the available Lys present in an ideal protein. Three diets were tested within each breed: 2 diets with an optimal essential AA pattern, containing 12 or 16% CP as-fed, or a Lys-deficient diet (35% of the recommended Lys content). This diet was supplied at 12% CP for the Iberian and 16% CP for the Landrace pigs, respectively. The contrasts made were breed x dietary protein concentration and breed x AA pattern (adequate vs. inadequate Lys content). Cumulative urinary (15)N excretion over 60 h after receiving an oral dose of [(15)N]-glycine was used to calculate N flux. Mean BW for Landrace and Iberian pigs were 25.8 +/- 0.55 kg and 30.8 +/- 0.74 kg, respectively. Protein deposition (g of N/(kg(0.75).d) was lower in the Iberian than in the Landrace gilts (4 to 16%; P = 0.002) and increased with dietary protein content. In contrast, protein synthesis and degradation [g of N/(kg(0.75).d)] were greater for the Landrace breed (16 to 18 and 23%, respectively, for the 2 dietary protein contents studied; P < 0.05), but no breed differences were detected in fractional protein synthesis and degradation rates. The ratio of protein synthesis:protein deposition (S/PD) did not change with dietary protein concentration or breed and achieved a mean value of 5.4. Irrespective of breed, Lys deficiency had a strong negative effect on N balance (P < 0.001) and increased the ratio of S/PD (P = 0.012). The greater rates of protein deposition, synthesis, and degradation in Landrace pigs than in Iberian pigs fed optimal AA-pattern diets were then attributed to differences in body protein mass. Consequently, these results validate the hypothesis of unequal synthesis and degradation, but not of unequal S/PD, between breeds.

Animal Feed↗
PubMed2005

Muscle fractional protein synthesis is higher in Iberian than in Landrace growing pigs fed adequate or lysine-deficient diets.

Protein deposition in Iberian pigs is low and the reasons for this are unknown. We investigated differences in protein synthesis rate in tissues of 30 Iberian and Landrace gilts fed 2 diets with adequate amino acid composition containing 160 or 120 g crude protein (CP)/kg, or a lysine-deficient diet (containing 120 or 160 g CP/kg for Iberian and Landrace pigs, respectively). Pigs were infused with a flooding dose of phenylalanine (15% as [(2)H(5)]-phenylalanine). Blood samples were taken from 12 to 40 min after the start of infusion, and samples from longissimus dorsi (ld), biceps femoris (bf), and semimembranosus (sm) muscles, liver, and duodenum were taken after slaughter. Body weights (BW) were 22.9 +/- 0.37 and 27.1 +/- 0.64 kg for Iberian and Landrace pigs, respectively. Iberian pigs fed the adequate diets had higher muscle fractional protein synthesis rates (FSR, %/d) than Landrace pigs. The FSR were 7.9 +/- 0.34 vs. 6.3 +/- 0.29%/d; 8.3 +/- 0.36 vs. 6.3 +/- 0.21%/d, and 7.7 +/- 0.23 vs. 6.4 +/- 0.36%/d for ld, bf, and sm muscles in Iberian and Landrace breeds, respectively (P < 0.01). However, muscles were between 20 and 32% smaller in the Iberian pigs (P < 0.01). Dietary protein level did not affect muscle FSR or size in either breed. Lysine deficiency reduced muscle FSR (46-49%, P < 0.001). Visceral tissues had greater relative weights in Iberian pigs (P < 0.001) with no breed differences in FSR. These findings might explain the low efficiency of protein and energy utilization by Iberian pigs compared with conventional pig breeds.

Amino Acids↗
PubMed2002

Glutamine metabolism in ovine splanchnic tissues: effects of infusion of ammonium bicarbonate or amino acids into the abomasum.

This study investigates the effects of increased NH3 or amino acid supply on glutamine utilisation and production by the splanchnic tissues of fed sheep. Six sheep, prepared with vascular catheters in the aorta, mesenteric, portal and hepatic veins, were fed grass pellets to 1.1 x energy maintenance requirements. Each treatment involved a 4 d abomasal infusion, of either ammonium bicarbonate (AMM; 234 micromol/kg(0.75 per min), water (CONT), or a mixture of amino acids that excluded glutamine and glutamate (AA; 46.8 micromol amino acid-N/kg(0.75) per min). The treatments simulated nutritional extremes in terms of the balance of absorbed N. Kinetics across the whole gut and the liver were monitored during an intra-jugular infusion of [5-(15N)]glutamine. Blood flow across the whole gut or liver were unaffected by treatment. Both AMM and AA infusions doubled the hepatic release of urea-N compared with CONT (P<0.02). AA infusion decreased arterial glutamine concentration by 26% (P<0.01) and 23 % (P<0.05) compared with AMM and CONT respectively. Despite this, whole-body glutamine flux was not affected by treatment. In contrast, AMM infusion increased hepatic glutamine production by 40% compared with CONT (P<0.02). This provided a mechanism to ensure NH3 supply to the periphery was maintained within the normal low physiological levels. Hepatic glutamine utilisation tended to increase during AA infusion, probably to ensure equal inflows of N to the ornithine cycle. Between 6 and 10% of NH3 absorbed across the digestive tract was derived from the amido-N of glutamine. Overall, splanchnic glutamine utilisation accounted for 45-70% of whole-body glutamine flux.

Abomasum↗
PubMed2002

The effect of dietary protein content and feeding level on the rate of protein deposition and energy utilization in growing Iberian pigs from 15 to 50 kg body weight.

The effects of dietary protein content and feeding level on the utilization of metabolizable energy (ME) and on the rates of gain, protein and fat deposition have been studied in seventy-two Iberian pigs growing from 15 to 50 kg body weight (BW) by means of comparative slaughter experiments. The animals were fed on six diets providing 223, 192, 175, 156, 129 and 101 g crude ideal protein ( CP)/kg DM and 14.64, 14.14, 14.37, 14.80, 15.36 and 15.53 MJ ME/kg DM respectively. Each diet was offered at three levels of feeding: 0.60, 0.80 and 0.95xad libitum intake. Protein deposition (PD) increased significantly (P<0.01) with each decrease in dietary CP content and reached a maximum value (74.0 g) when the diet providing 129 g CP/kg DM (6.86 g digestible ideal protein/MJ ME) was offered at the highest feeding level. This feeding regimen resulted in average values for live-weight gain and retained energy (RE) of 559 g/d and 10.9 MJ/d respectively. RE increased significantly (P<0.001) from 480 to 626 kJ/kg BW0.75 with each decrease in dietary CP content from 192 to 129 g/kg DM. Raising the level of feed intake led to significant linear increases in PD and RE irrespective of the diet fed (P<0.001). When diets approaching an adequate supply of CP were given, the net efficiency of use of ME for growth (kw) and the maintenance energy requirements were 58.2 % and 422 kJ/kg BW0.75 per d respectively.

Adipose Tissue↗
PubMed1999

Tissue sequestration of C-labelled bicarbonate [HCO3-] in fed and fasted young sheep.

Carbon dioxide entry rates (CER) based on isotopic activities in either expired air or blood following a 24-h intravenous infusion of [13C]- and [14C] sodium bicarbonate were compared with CO2 production quantified by respiration hood in young sheep (28-30 kg) either fed (three animals) or fasted (three animals). CO2 production increased with intake (5.2 vs 10.3 mol/day; P < 0.001) as did CER values based on expired air (9.9 vs 18.6 mol/day; P < 0.001) or blood (7.5 vs 16.5 mol/day; P < 0.001). The differences between air and blood CER values were significant (P < 0.001). There were no differences, however, when data were compared between [13C] and [14C] measurements. How much of these differences could be attributed to sequestration of label in body tissues was examined at the end of the infusion. The highest specific radioactivities (dpm/g dry matter) in acid-fast tissue material were observed for the more metabolically active tissues, liver, jejunum and kidney, with the lowest values for fat and muscle. When tissue mass was taken into account, however, the largest proportions of the dose sequestered were in bone muscle, skin and fat with significantly more retained for the former three (P < 0.01) during fasting. Separately, losses as urinary urea were also quantified. Total measured sequestration of label only accounted for approximately 24-44% of the difference between CER and CO2 production.

Animals↗
PubMed1999

Responses in the absorptive phase in muscle and liver protein synthesis rates of growing rats.

The effect of time after beginning of a meal (30, 60, 90 and 120 min) on liver and gastrocnemius muscle protein synthesis was tested in growing male rats using the large dose technique, based on a 10 min exposure to [15N]phenylalanine. The fractional synthesis rate was estimated from the ratio between the atom percent excess of tissue protein-bound and free labelled phenylalanine. The latter was measured by gas chromatography mass spectrometry using the tertiary-butyldimethylsilyl amino acid derivatives. The protein-bound phenylalanine of gastrocnemius muscle was separated from the other amino acids using preparative amino acid chromatography and then oxidised to N2 in an automated carbon-nitrogen Roboprep (CN) combustion module attached to a continuous flow isotope ratio mass spectrometer (IRMS), with m/z ions 28 and 29 monitored. The protein-bound phenylalanine from liver was separated by a gas chromatograph attached to a sample preparation module and an isotope ratio mass spectrometer (GC C-IRMS), with again m/z ions of 28 and 29 monitored. The following results were obtained: the daily fractional protein synthesis rates (ks) in gastrocnemius muscle and liver were 13.9% and 65.6% respectively, in 12 h fasted 145 g rats. These ks increased within 30 min after ingestion of meal to 14.9% and 91.8% for muscle and liver, respectively, and remained at these values for the next 90 min (14.6% and 87.4% at 60 min, and 14.3% and 88.6% at 120 min after the beginning of feeding). It was concluded that measurement of protein synthesis rates characteristics for the absorptive phase can be undertaken in a period from thirty minutes to two hours after start of a meal, without significant changes in the ks values.

Amino Acids↗
PubMed1998

Transfers of N metabolites across the ovine liver in response to short-term infusions of an amino acid mixture into the mesenteric vein.

The effect of acute (4.5 h) infusions into the mesenteric vein of an amino acid (AA) mixture, which simulated the composition of rumen microbial protein, on net transfers of NH3, urea and total AA across the portal-drained viscera (PDV) and liver in the ovine has been examined. Four wether sheep were surgically prepared with vascular catheters across the PDV and liver (Lobley et al. 1995) and were offered a basal diet of 1000 g grass pellets/d (approximately 1.4 x energy maintenance). Each animal was infused at weekly intervals with one of four dilutions of the AA mixture. These dilutions provided 0.44, 0.88, 1.32 and 1.84 mmol AA-N/min infused, the lowest of which approximately doubled the net absorption of AA-N from the basal diet. Animals were treated with heparin to allow continuous collection of blood by peristaltic pump for 2 h preceding, and between 0.5-2.5 and 2.5-4.5 h after, the start of the AA infusions. Blood flow in the hepatic artery increased (100 v. 208 g/min; P = 0.002) in response to AA infusion, while hepatic portal venous flow decreased (2090 v. 1854 g/min; P = 0.006). The AA infusion also stimulated O2 uptake by the PDV (P < 0.001) and liver (P = 0.016). Absorption across the PDV and hepatic removal of NH3 were unchanged between basal and amino acid infusion conditions. Urea-N removal across the PDV was unaltered, but hepatic production increased (P < 0.001) with level of AA infusion. During infusions, net appearance of AA across the PDV was below the theoretical level. This may have been due to inhibition of AA uptake from the small intestine, and/or increased removal by the digestive tract of AA from the systemic circulation associated with greater arterial concentrations. Hepatic extraction of AA increased with level of infusion, both for total AA and those included in the infusate. Total hepatic urea-N production tended towards a maximum (estimated as 2 mumol N/g liver wet weight per min). The AA removed by the liver and not used for ureagenesis remained similar (170 mumol AA-N/min) between basal and AA infusions. This was presumed available for anabolic purposes (mainly synthesis of export proteins). The proportion of net AA-N appearance (absorption plus infused) across the PDV removed by the liver declined from 0.71 to 0.53 between basal and AA infusions. In contrast to findings from cattle (Wray-Cahen et al. 1997), increased AA infusion did not alter the net removal of glutamine across the liver. This may reflect differences between the studies in NH3: AA-N absorbed. Further differences between the cattle study and the current findings may relate to the different physiological state (pregnancy v. growth), which may alter the partition of AA between anabolic and catabolic fates.

Amino Acids↗
PubMed1997

Effect of a low protein diet on the energy metabolism of growing chickens.

Two slaughter experiments were carried out to determine whether the protein content of the diet has an influence upon the efficiency of utilization of ME in fast growing chickens. A normal-protein diet (NPD, 204 g CP/kg DM: 14.7 MJ ME/kg DM) based on soybean meal as the sole source of protein was given at four different levels of intake (ad libitum or restricted at about 90, 65 and 40% ad lib) to 10-d-old animals for 2 weeks. In a parallel experiment the chickens were fed ad libitum a low protein diet (LPD, 66 g CP/kg DM: 15.0 MJ ME/kg DM) based on soybean meal. The intake of metabolizable energy ranged from 1675 to 777 and 1770 to 832 kJ/kgW0.75 per day for NPD and LPD treatments, respectively. Mean values of energy retention, gross efficiency of energy utilization and energy retained as protein were significantly (P < .05) lower and heat production (expressed as both kJ/kgW0.75 per day and kJ/kg body protein content0.75 per day) was significantly higher (P < .05) for the chickens fed on LPD. These findings support the concept of dietary-induced thermogenesis in response to reductions in dietary protein concentration. It is concluded that the increased heat production found in the birds fed on the low-protein diet can be explained by both an increase in energy requirements for maintenance (MEm) and a sharp decrease in the efficiency of utilization of ME of growth (k(g)).

Animal Nutritional Physiological Phenomena↗
PubMed1996

Method for the determination of 15NH3 enrichment in biological samples by gas chromatography/electron impact ionization mass spectrometry.

An alternative method for the determination of [15N]ammonia enrichment in biological fluids was developed. It is based on the use of glutamate dehydrogenase of bovine liver (EC 1.4.1.2.) with 2-oxopentanoic acid as substrate, to convert the ammonia present in the sample into norvaline, the enrichment of which can be measured by gas chromatography/mass spectrometry as its tertiary butyldimethylsilyl (TBDMS) derivative under electron impact selective ion recording (SIR) conditions. The principal advantage of the present approach is that it is simpler and quicker than the previously described methods, because the synthetic product, norvaline, is not present in biological fluids and pre-processing of the sample is unnecessary. The procedure includes a pre-incubation stage which allows removal of contaminant ammonia present in the reagents used for the enzyme reaction. The contributions of other sources of nitrogen to norvaline production have been checked and quantified: these may provide limitations of the technique when samples for analysis are low in ammonia (e.g. arterial or hepatic venous blood). To reduce these contributions, short times of incubation are proposed. The results from two experiments in vivo in which two sheep were infused with [15N]ammonium chloride in the mesenteric vein are presented and the biological implications which arise from the results are discussed. The validity of the procedures was demonstrated by the quantitative recovery from the mesenteric and portal veins of [15N]ammonia infused.

Ammonia↗
PubMed1995

Effect of dietary protein quality on energy metabolism in growing chickens.

A slaughter experiment was carried out to study the effect of dietary protein quality on maintenance energy requirements and energy costs for protein accretion and fat deposition in fast-growing broiler-type male chickens. Three isonitrogenous (200 g crude protein/kg DM) and isoenergetic (14 kJ metabolizable energy (ME)/g DM) semipurified diets based on soyabean meal unsupplemented (diet S) or supplemented with 20 g L-lysine/kg (diet SL) or 2 g DL-methionine/kg (diet SM), in order to promote a decrease or an increase in growth rate respectively, were selected and given at four feeding levels (ad lib. or restricted to 40, 28 and 18 g DM/d, on average) to 10-d-old fast-growing male broiler-type chicks for 2 weeks. Both the efficiency with which ME was used to support growth (kg) and the maintenance requirements (MEm) significantly decreased inversely to the biological value of the dietary protein (kg = 0.660, 0.600 and 0.572; MEm = 597, 522 and 464 kJ/kg W0.75 per d, for diets SL, S and SM respectively). The partial efficiencies of use of ME for protein accretion (kp) or fat deposition (kf) were also inversely related, the former increasing with the quality of the protein offered. An alternative procedure was used to try to overcome the statistical problems inherent in the partition of ME between fat and protein.

Animal Feed↗
PubMed1994

Effect of dietary protein quality, feed restriction and short-term fasting on protein synthesis and turnover in tissues of the growing chicken.

The effect of dietary protein quality and quantity on fractional rates of protein synthesis (ks) and degradation (kd) in the skeletal muscle, liver, jejunum and skin of young growing chickens was studied. Chickens were either fasted overnight or were fed at frequent intervals, using continuous feeders, with equal amounts of a diet containing soya-bean meal as the sole protein source, unsupplemented, or supplemented with either lysine or methionine. Each of the three diets was provided at 2 or 0.9 x maintenance. On the higher intake, birds on the unsupplemented diet gained weight, lysine supplementation decreased and methionine supplementation increased body-weight gain (by -23% and +22% respectively). Birds fed at 0.9 x maintenance lost weight; supplementation with methionine or lysine did not influence this weight loss. None of the dietary regimens had significant effects on protein synthesis rates in any of the tissues, thus the mechanism whereby muscle mass increased in response to methionine supplementation appeared to be a decrease in the calculated rate of protein degradation. Similarly, on the 0.9 x maintenance diet the failure of the animals to grow appeared to be due to an increase in the rate of protein degradation rather than an effect on synthesis. Conversely, muscle ks was decreased in fasted chickens previously fed on the unsupplemented diet at 2 x maintenance, and in birds which had received the 0.9 x maintenance diet fasting resulted in a similar reduction in protein synthesis in muscle; ks in the liver and jejunum was also significantly decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Nutritional Physiological Phenomena↗
PubMed1993

[Subxiphoid drainage of pericardial effusions].

Subxiphoid drainage of chronic or persistent effusion was done on five patients (three women and two men) in a twelve-month period. The average age was 30 years. All patients had symptoms and two had a diagnosis of cardiac tamponade. Every patient had an echocardiogram. Subxiphoid drainage was done by creating a pericardial window. Three patients were done with local and two under general anesthesia. There was no morbidity or mortality, associated with the procedure. Two of the effusions were idiopathic and one each was purulent, uremic or metastatic. The patients were followed for an average of 6.5 months and all remained asymptomatic and without evidence of recurrent pericardial effusion. This procedure is effective in the treatment of persistent pericardial effusions. It is an easy and fast operation with low morbidity and mortality, which allows it to be used in patients who are high surgical risks.

Adult↗
PubMed1993

[Toxic cardiomyopathy due to cocaine use].

The clinical record of 5 patients are studied. They were hospitalized in Santo Tomás Hospital with history of chronic and massive intoxication with inhaled and ingested cocaine. They all had cardiomegaly: in one, of grade I; in three, of grade III. The echocardiography mode B showed global cardiomegaly with dilatation of cavities and ejection fraction of 20% or below.

Adult↗
PubMed1992

Ultrastructural immunohistochemical localization of polyclonal IgG, C3, and amyloid P component on the congo red-negative amyloid-like fibrils of fibrillary glomerulopathy.

Renal biopsies from seven patients with Congo red-negative amyloid-like fibrillary glomerulopathy (FGP) were examined by protein A gold immuno-electron microscopy. Ultrastructurally, the fibrils in all cases exhibited positive immunostaining for IgG, both Ig light chains, C3, and amyloid P component (AP), but did not show positive immunostaining for glomerular basement membrane (GBM)-associated proteins (collagen type IV and heparan-sulfate proteoglycans) or microfibril-associated proteins (fibronectin and fibrillin). In a triple-label study, AP and IgG were colocalized along the same fibril, whereas the gold probes for the detection of collagen type IV were absent. The results suggest that the fibrils are comprised of polyclonal IgG and C3 that bind AP. AP was immunolocalized sparsely but regularly along the lamina rara interna of normal GBM. AP was absent in the fibrils in a case of diabetic glomerulopathy, was scattered randomly without specificity for the electron-dense deposits in the GBM of membranous glomerulopathy, and lined up regularly along the fibrils in amyloid deposits. FGP is an entity in which the fibrils bind AP but lack the beta-pleated sheet structure necessary for Congo red staining that is typical of amyloid.

Amyloid↗