Serum Urea Nitrogen Concentrations Research Articles

The Effects of Dietary Supplementation with Chromium Picolinate throughout Gestation on Productive Performance, Cr Concentration, Serum Parameters, and Colostrum Composition in Sows

The objective of this study was to determine the effects of supplemental chromium as chromium picolinate (CrPic) on productive performance, chromium (Cr) concentration, serum parameters, and colostrum composition in sows. Thirty Yorkshire sows were bred with semen from a pool of Landrace boars. The sows were equally grouped and treated with either a diet containing 0 (control) or 400 ppb dietary Cr supplementation throughout gestation. The sows received the same basal diet based on corn-DDGS meal. Supplemental CrPic increased (P < 0.05) the sow body mass gain from the insemination to the day 110 of gestation in sows. No differences (P > 0.50) were observed in the gestation interval, sow mass, and backfat at insemination, after farrowing, at weaning and lactation loss. The number of piglets born alive, piglets per litter at weaning, and litter weaned mass were increased (P < 0.05) for those supplemented with CrPic compared with the control. However, the total number of piglets born, total born litter mass, average piglet birth body mass, born alive litter mass, and average born alive piglet mass did not differ among the treatments (P > 0.05). The placental masses of sows were similar among treatments (P > 0.05). Dietary supplementation with CrPic throughout gestation in sows showed increased (P < 0.01) concentration of Cr in the colostrum or serum at days 70 and 110. Compared with the control group, dietary supplementation with CrPic throughout gestation in sows decreased (P < 0.05) the serum insulin concentration, the glucose or serum urea nitrogen concentration at days 70 and 110. However, no differences (P > 0.05) were observed in total protein concentration among treatments. No differences (P > 0.05) were observed in total solids, protein, fat or lactose among sows fed the diets supplemented with CrPic compared with the control. This exciting finding provides evidence for an increase in mass gain and live-born piglets in sows supplemented with CrPic throughout gestation.

Preoperative factors associated with postoperative hypocalcemia in dogs with primary hyperparathyroidism that underwent parathyroidectomy: 62 cases (2004–2009)

To identify preoperative variables associated with postoperative hypocalcemia in dogs with primary hyperparathyroidism undergoing parathyroidectomy. Retrospective case series. 62 dogs. Medical records of dogs undergoing parathyroidectomy for treatment of primary hyperparathyroidism between January 2004 and January 2009 at 4 institutions were reviewed; data regarding various preoperative variables and postoperative serum total and ionized calcium concentrations were recorded. Preoperative ultrasonographic and surgical findings were compared regarding laterality (right, left, or bilateral) of parathyroid gland lesions. Data were analyzed via ANOVA, simple linear regression, and multiple linear regression to identify associations between preoperative variables and postoperative serum total and ionized calcium nadir concentrations. Preoperative variables significantly associated with low postoperative serum total calcium nadir concentrations included old age, history of weakness, lack of gastrointestinal tract signs, high serum parathyroid hormone concentration, and low serum calcium-phosphorus concentration product value. Preoperative variables significantly associated with low postoperative serum ionized calcium nadir concentrations included sexually intact status, low body weight, high serum urea nitrogen concentration, and lack of polyuria and polydipsia in the history. Age, body weight, serum calcium-phosphorus concentration product, and serum concentrations of parathyroid hormone and urea nitrogen were included in the final multiple linear regression model for prediction of postoperative serum calcium concentrations. Ultrasonography was performed in 58 dogs; results for 44 (75.9%) dogs agreed with surgical findings regarding laterality of parathyroid gland lesions. Prediction of postoperative hypocalcemia in dogs in this study with primary hyperparathyroidism that underwent parathyroidectomy was difficult and depended on multiple (history, physical examination, and clinicopathologic) factors.

Hypocaloric, High‐Protein Nutrition Therapy in Older vs Younger Critically Ill Patients With Obesity

Older patients require more protein than younger patients to achieve anabolism, but age-associated renal dysfunction may limit the amount of protein that can be safely provided. This study examined whether older, critically ill trauma patients with obesity can safely achieve nitrogen equilibrium and have positive clinical outcomes similar to younger obese patients during hypocaloric, high-protein nutrition therapy. Adult patients with traumatic injury and obesity (body mass index [BMI] >30 kg/m(2)), admitted to the Presley Trauma Center from January 2009 to April 2011, were evaluated. Patients were targeted to receive hypocaloric, high-protein nutrition therapy (<25 kcal/kg ideal body weight [IBW]/d and >2 g/kg IBW/d of protein) for >10 days. Patients were stratified as older (≥60 years) or younger (18-59 years). Seventy-four patients (33 older, 41 younger) were studied. Older and younger patients were similar in BMI and injury severity. When given isonitrogenous regimens (2.3 ± 0.2 g/kg IBW/d), nitrogen balance was similar between older and younger patients (-3.2 ± 5.7 g/d vs -4.9 ± 9.0 g/d; P = .363). Older patients experienced a greater mean serum urea nitrogen concentration than younger patients (30 ± 14 mg/dL vs 20 ± 9 mg/dL; P = .001) during nutrition therapy. Clinical outcomes were not different between groups. Older critically ill trauma patients exhibited an equivalent net protein response as younger patients during hypocaloric, high-protein nutrition therapy. Older patients are at greater risk for developing azotemia. Close monitoring is warranted.

Estimation of glomerular filtration rate in rabbits by a single-sample method using iodixanol

To estimate the glomerular filtration rate (GFR) in conscious rabbits, a single-sample method using the non-ionic contrast medium iodixanol was compared with a three-sample method using the standard agent inulin. Iodixanol and inulin were co-administered intravenously to male New Zealand White rabbits at 60 mg I/kg and 40 mg/kg, respectively, and blood was collected 30, 60, 90 and 120 min later. Serum iodixanol and inulin concentrations were separately determined by high performance liquid chromatography and colorimetry, respectively. Serum urea nitrogen (UN) and creatinine concentrations were also determined. Based on the data from healthy and cisplatin-treated rabbits, the GFR estimated by iodixanol was well consistent with that by inulin. Further, when the GFR decreased to more than 60% of the reference value, serum creatinine concentrations became elevated. However, serum UN concentrations exhibited wide fluctuations, presumably due to a difference in renal handlings. The single-sample method using iodixanol was considered to be an expedient tool in both clinical and research settings, because the stress due to a multi-sample method was reduced.

Estimation of the ideal standardized ileal digestible tryptophan to lysine ratio for growing pigs fed low crude protein diets supplemented with crystalline amino acids

Tryptophan is typically regarded as the second or third limiting amino acid (AA) in low-crude protein (CP), corn-soybean meal based diets fed to growing swine. However, there is limited data available concerning the ideal standardized ileal digestible (SID) Trp to Lys ratio for growing pigs fed low-CP diets supplemented with crystalline AA. Therefore, the aim of this study was to evaluate the Trp requirement for 25–50kg pigs, expressed as a SID Trp to Lys ratio, using swine housed under commercial conditions. In Experiment 1, 144 growing pigs were used to identify a diet deficient in Lys. The pigs were fed either a high-CP (18.6%) diet with 1.02% SID Lys or one of two low-CP diets (CP content reduced by four percentage units but supplemented with crystalline Lys, Trp, Met, Thr, Ile, and Val) providing 0.9 or 1.02% SID Lys, respectively. Each diet was fed to six pens containing eight pigs (4 barrows and 4 gilts) per pen. The weight gain (688g/day) of pigs receiving the low-CP diet containing 0.9% SID Lys was lower (P=0.03) than that of pigs fed diets containing 1.02% SID Lys with a high- (758g/day) or low-CP (747g/day) content, confirming that this diet was deficient in Lys and, therefore, 0.9% SID Lys was used in the basal diet fed in Experiment 2. Experiment 2 was a dose–response study involving 300 growing pigs, in which graded levels of crystalline Trp were used to produce five diets providing SID Trp to Lys ratios of 13, 16, 19, 22, or 25%. Each diet was fed to six pens containing ten pigs (five barrows and five gilts) per pen. Serum Ile, Leu, Phe, and Trp concentrations linearly increased (P<0.05) as the dietary SID Trp to Lys ratio increased. In contrast, serum urea nitrogen (SUN) and Ala concentrations linearly decreased (P<0.05) as the dietary SID Trp to Lys ratio increased. The SID Trp to Lys ratios that maximized weight gain, feed conversion ratio, and SUN were 19.7, 20.0, and 20.8% using a linear-breakpoint model and 22.6, 23.2, and 23.6% using a curvilinear–plateau model. Taking an average of these six values, we conclude that the optimum SID Trp to Lys ratio is at least 22% for 25–50kg growing pigs fed low-CP diets supplemented with crystalline AA.

Simplified procedure for the estimation of glomerular filtration rate following intravenous administration of iodixanol in cats

To compare the use of a single-sample method involving IV administration of iodixanol with a multisample method involving inulin for the estimation of glomerular filtration rate (GFR) in cats. 24 cats, including 15 healthy cats and 9 cats with naturally occurring renal diseases. Each cat was coadministered iodixanol (a nonionic contrast medium; dose providing 40 mg of I/kg) and inulin (50 mg/kg), IV, and blood samples were collected 60, 90, and 120 minutes later. Serum iodixanol and inulin concentrations were determined by means of high-performance liquid chromatography and colorimetry, respectively. Serum urea nitrogen and creatinine concentrations were also measured. Analysis of the data from healthy cats and cats with naturally occurring renal diseases revealed an excellent correlation between GFR values estimated by the multisample and single-sample methods with iodixanol. Likewise, GFR values estimated from the single-sample method with iodixanol were closely correlated with those calculated from the multisample method with inulin. For estimation of GFR in cats, use of a single-sample method with iodixanol, instead of a multisample procedure, may be an expedient tool in both clinical and research settings because of its benefits to patient well-being as a result of reduced stress associated with blood sample collection.

Measured degree of dehydration in children and adolescents with type 1 diabetic ketoacidosis*

Successful management of diabetic ketoacidosis depends on adequate rehydration while avoiding cerebral edema. Our objectives are to 1) measure the degree of dehydration in children with type 1 diabetes mellitus and diabetic ketoacidosis based on change in body weight; and 2) investigate the relationships between measured degree of dehydration and clinically assessed degree of dehydration, severity of diabetic ketoacidosis, and routine serum laboratory values. Prospective observational study. University-affiliated tertiary care children's hospital. Sixty-six patients <18 yrs of age with type 1 diabetic ketoacidosis. Patients were weighed using a portable scale at admission; 8, 16, and 24 hrs; and daily until discharge. Measured degree of dehydration was based on the difference between admission and plateau weights. Clinical degree of dehydration was assessed by physical examination and severity of diabetic ketoacidosis was assessed by blood gas values as defined by international guidelines. Laboratory values obtained on admission included serum glucose, urea nitrogen, sodium, and osmolality. Median measured degree of dehydration was 5.2% (interquartile range, 3.1% to 7.8%). Fourteen (21%) patients were clinically assessed as mild dehydration, 49 (74%) as moderate, and three (5%) as severe. Patients clinically assessed as moderately dehydrated had a greater measured degree of dehydration (5.8%; interquartile range, 3.6% to 9.6%) than those assessed as mildly dehydrated (3.7%; interquartile range, 2.3% to 6.4%) or severely dehydrated (2.5%; interquartile range, 2.3% to 2.6%). Nine (14%) patients were assessed as mild diabetic ketoacidosis, 18 (27%) as moderate, and 39 (59%) as severe. Diabetic ketoacidosis severity groups did not differ in measured degree of dehydration. Variables independently associated with measured degree of dehydration included serum urea nitrogen and sodium concentration on admission. Hydration status in children with diabetic ketoacidosis cannot be accurately assessed by physical examination or blood gas values. Fluid therapy based on maintenance plus 6% deficit replacement is reasonable for most patients.

Daytime Rhythm and Treatment-Related Fluctuations of Serum Phosphorus Concentration in Dialysis Patients

Background: Serum phosphorus concentrations reflect a dynamic balance between generation, exchanges, and removal. Time-averaged phosphorus concentrations (TAC_phos) reflect the overall exposure better than single time-point concentrations, especially in dialysis patients treated with an intermittent modality. The present study aimed to determine the daytime rhythm of phosphorus in dialysis patients and to compare the TAC_phos in continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis (HD) patients. Methods: Serum concentrations of urea nitrogen, creatinine and phosphorus were determined at regular intervals in 10 healthy volunteers (HV), 8 CAPD patients and 10 HD patients. In HV and CAPD patients, blood was sampled at 08:30 (fasting), 09:30, 10:30, 12:30, 16:30, and 08:30 h the next day. In HD patients, blood was sampled before and after the midweek dialysis session and rebound was assessed at regular time-points post-dialysis. TAC_phos were determined according to the trapezoidal rule. Results: Serum phosphorus levels show a daytime rhythm in CAPD patients, similar to what is observed in HV, with a nadir around 10:30 h and a rise in the afternoon. The magnitude of this daytime fluctuation is limited as compared to the treatment-related fluctuations in HD. These important fluctuations also translate in predialysis serum phosphorus concentrations overestimating the TAC. Remarkably, TAC_phos were significantly lower in HD as compared to CAPD patients. Conclusions: Daytime phosphorus rhythm is preserved in CAPD patients. These fluctuations are limited as compared to fluctuations in HD patients. Treatment-related fluctuation should be accounted for when comparing phosphorus exposure between different groups.

Use of end-to-side arterial and venous anastomosis techniques for renal transplantation in two dogs

A sexually intact male Old English Sheepdog and a sexually intact female Bull Terrier were evaluated for renal dysplasia and chronic renal failure, respectively. Both dogs were anemic and had high serum concentrations of urea nitrogen and creatinine. Electrolyte abnormalities (calcium and phosphorus) were also evident. The decision was made to pursue renal transplantation, and donor dogs were identified. End-to-side anastomosis of the renal artery and vein of each donor's left kidney to the recipient's ipsilateral external iliac artery and vein, respectively, was performed. The left caudal abdominal musculature was scarified by making an incision, and nephropexy to that musculature was performed with a simple interrupted pattern of polypropylene sutures. No intraoperative or postoperative complications associated with the vascular anastomoses were encountered. Azotemia, anemia, and electrolyte imbalances resolved after transplantation. The end-to-side anastomosis technique described here, which is a preferred method in human medicine, was successful, providing an alternative to other renal transplantation techniques in dogs. Additional studies are needed to determine whether any vascular anastomosis technique is preferable for use in dogs requiring renal transplantation.

Serum metabolites, ghrelin and leptin are modified by age and/or diet in weanling kittens fed either a high‐ or moderate‐protein diet

The objective of this study was to evaluate the effects of in utero and postnatal exposure of a high-protein (HP; n=9) or moderate-protein (MP; n=16) diet on growth, and serum metabolite, ghrelin and leptin concentrations during the first 4 months of life in kittens. It was hypothesized that blood indices would be modified due to diet. Blood samples were collected from kittens at 4, 8, 12 and 16 weeks of age. Kittens were weaned at 8 weeks of age onto the same diet as the dam. Body weight was measured weekly from birth and daily food intake for each litter was recorded post-weaning. Serum concentrations of urea nitrogen, total protein and triglycerides were greater (P<0.05) in kittens fed the HP diet. Serum cholesterol concentrations were greater (P <0.05) in MP-fed kittens at 4 weeks of age. Moderate-protein fed kittens tended to have greater (P < 0.10) serum ghrelin concentrations. Leptin concentrations were not affected by diet, but changed over time (P<0.05). Our data indicate that diet and age of kittens affect circulating concentrations of peptides important in appetite regulation. Further research testing the effects of in utero and early postnatal nutrient exposure on feline obesity risk in adulthood is needed.

Estimation of glomerular filtration rate in calves using the contrast medium iodixanol

To develop a simple procedure for estimating glomerular filtration rate (GFR) in calves, a three-sample method using iodixanol was first compared to that using the standard agent inulin. Iodixanol and inulin were co-administered intravenously to calves at 40 mg I/kg and 40 mg/kg, respectively, and blood was collected 30, 60, 120, and 180 min later. Serum iodixanol and inulin concentrations were separately determined by high performance liquid chromatography and colorimetry. Serum urea nitrogen (UN) and creatinine concentrations were also measured. GFR estimated by iodixanol was consistent with that using inulin in clinically healthy calves. Based on GFR estimations in healthy calves and those renal-loaded with iodixanol, it was found that the serum creatinine concentrations became elevated when GFR decreased to 60% of the reference value. In contrast, serum UN concentrations fluctuated widely, presumably due to extra-renal factors. When GFR was estimated using the three-sample method and compared with the single-blood-sample method, 62/69 (90%) of samples tested were within the agreement plots. The results demonstrated that the single-blood-sample method using iodixanol may be useful in monitoring GFR in calves.

Colorimetric assay for the quantification of serum iodixanol concentration and its application on estimation of glomerular filtration rate in cattle

A colorimetric assay used to quantify the non-ionic contrast medium iodixanol in sera was validated and compared with high-performance liquid chromatography. The application of this assay to estimate glomerular filtration rates (GFR) in cattle was examined. Serum iodixanol was de-iodinated by alkaline hydrolysis and the amount of released iodine was subsequently determined using a ceric arsenite method. There was a close correlation between the two methods using identical specimens. In clinically healthy cattle with different body weights, the reference value (166.3–178.8mL/min/m2) based on body surface area was fairly stable as compared with that (2.13–3.63mL/min/kg) based on body weight. Based on GFR data in healthy and renal-impaired cattle, when the GFR decreased to more than 60% of the reference value, serum urea nitrogen and creatinine concentrations increased. The colorimetric assay is a simple method for the estimation of GFR in cattle and requires no expensive equipment.

Comparison of Growth Hormone Pulsatile Secretion and Serum Metabolites in Growing Taihu and Landrace Pigs

In this paper we compared growth performance, growth hormone (GH) pulsatile secretion and serum metabolites in growing Taihu and Landrace gilts at the same age. The results showed that compared with Landrace gilts, Taihu gilts decreased by 45.48% (P&lt;0.05), 25.25% (P&lt;0.05) in average daily gain and carcass muscle percentage, and increased by 52.44% (P&lt;0.05), 69.50% (P&lt;0.05) in feed/gain ratio and carcass fat percentage, respectively. While, average daily feed intake was not affected by breeds. Serum basal GH level, mean GH level and GH pulse amplitude were decreased by 26.67% (P&lt;0.05), 20.00% (P&lt;0.05) and 18.81% (P&lt;0.05), respectively, but GH pulse frequency and pulse duration remained unchanged (P&gt;0.05). Serum urea nitrogen concentration in Taihu gilts was 32.04% (P&lt;0.05) higher, whereas, total protein level was 17.73% (P&lt;0.05) lower than that of Landrace gilts.

Effects of keratinase supplementation of corn-soybean meal based diets on apparent ileal amino acid digestibility in growing pigs and serum amino acids, cytokines, immunoglobulin levels and loin muscle area in nursery pigs

Two experiments were conducted to evaluate effects of keratinase for growing and nursery pigs. In Exp. 1, six pigs (32.3 ± 2.8 kg body weight), fitted with a simple T-cannula at the distal ileum, were assigned to one of two 3 × 3 Latin squares involving three periods and three diets including a basal diet and the same diets supplemented with 0, 0.05 or 0.1% keratinase. Dietary keratinase supplementation increased the apparent ileal digestibility of crude protein (CP), arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, alanine, glutamic acid and proline (p < 0.05). Digestibility coefficients did not differ between pigs fed 0.05 and 0.1% keratinase. In Exp. 2, 24piglets weaned at 30 ± 2 d of age were used in a 2 × 2 factorial design experiment with two CP concentrations (19 vs. 22%) and two levels of keratinase supplementation (0 vs. 0.05%). Keratinase supplementation increased (p < 0.05) average daily gain, serum arginine concentration and loin muscle area but decreased (p < 0.05) serum interleukin-10 concentrations. The reduction in dietary CP level decreased (p < 0.05) serum urea nitrogen concentrations, isoleucine, serine and proline concentrations, but increased serum arginine concentrations. Few interactions between keratinase supplementation and dietary CP concentration were observed. This study indicated that dietary keratinase supplementation improved apparent ileal amino acid digestibility for growing pigs and had a positive effect on weight gain, immune response and loin muscle area for nursery pigs.

Optimum conditions for serum clearance of iodixanol, applicable to the estimation of glomerular filtration rate in horses

To estimate the glomerular filtration rate (GFR) in horses, an optimum dose of the nonionic contrast medium iodixanol as a tracer was assessed with blood-sample times. Iodixanol was administered intravenously at 10-40 mg I/kg to geldings and mares, and blood was collected 30, 60, 90, 120, 150, and 180 min later. Serum iodixanol concentration was determined by high-performance liquid chromatography (HPLC), and serum urea nitrogen (UN) and creatinine concentrations were also measured. The combination of 20 mg I/kg iodixanol and sampling times of 60, 90, and 120 min after injection was considered to be appropriate for practical use. In clinically healthy horses, the reference values were determined to be 1.90 ± 0.03 ml/min/kg (150.8 ± 2.94 ml/min/m2), consistent with historical data using different tracers. The result suggests that serum clearance of iodixanol is a ready-to-use tool for a screening of alterations in the equine GFR, although it is necessary to perform a more longitudinal study using horses with a variety of renal functions.

Feed consumption, nutrient utilization and serum metabolite profile of captive blackbucks (Antelope cervicapra) fed diets varying in crude protein content

A feeding trial was conducted to determine the optimum level of crude protein (CP) in the diet of captive blackbuck (Antelope cervicapra) in which feed consumption and nutrient utilization are maximal. Fifteen blackbucks (BW 25-34 kg) were distributed into three groups of five each in an experiment of 75-days duration including a digestion trial of 5-day collection period. All the animals were offered 200 g of concentrates and fresh maize fodder ad libitum. The overall CP content of the three respective diets was 6.9%, 10.4% and 12.7%. Blood samples were collected on the last day of the experiment. Intake and digestibility of CP increased (p < 0.01) with the increased level of CP in the diet. Feed consumption and nutrient intake were not significantly different among the groups. However, digestibilities of most of the nutrients were higher in the 10.4% CP diet than in the 6.9% CP diet. The endogenous loss of nitrogen was similar among the groups. Based on the endogenous losses, minimum N requirement was calculated to be 776 mg/kg BW(0.75) /day, and to meet this requirement, diet must contain at least 8.27% CP. Serum urea nitrogen concentration increased (p < 0.01) with increased level of dietary CP. Serum level of glutamate oxaloacetate transaminase and glutamate pyruvate transaminase was higher (p < 0.05) in the group fed 6.9% CP diet. Animals in the group fed low protein diet also lost body mass during the experimental period. It was concluded that a diet containing 10.4% CP was optimum for maximizing nutrient utilization without any adverse effect on voluntary feed consumption and serum metabolite profile of blackbucks.

Role of the expression of heat shock protein 70 and heme oxygenase-1 in reduction of renal ischemia-reperfusion injury by iscbemic postconditioning in rats

[ Abstract] Objective To evaluate the role of the expression of heat shock protein 70 （HSP70） and heme oxygenase-1 （HO-1） in the reduction of renal ischemia-reperfusion （I/R） injury by ischemic postconditioning in rats. Methods One hundred and forty healthy male SD rats weighing 250-280 g were randomized into 4 groups （ n = 35 each） ： sham operation group （S group） ; I/R group; ischemic postconditioning group （IPo group） ; quer- cetin （an inhibitor of HSP） ＋ ischemic postconditioning group （Q ＋ IPo group）. Renal I/R was produced by clamping bilateral renal pedicels for 45 min followed by reperfusion. In group S, bilateral kidneys were only ex- posed through a midline incision but their pedicels were not clamped. In IPo and Q ＋ IPo groups, 45 min isehemia was followed by three 10 s episodes of ischemia at 10 s intervals for reperfusion and in addition intraperitoneal quer- cetin 100 mg/kg was injected at 1 h before ischemia in group Q ＋ IPo. Blood samples from hearts were obtained at 0, 1, 3, 6, 12, 24 and 48 h of reperfusion （T0.6） and the rats were then sacrificed and kidneys removed to detect the expression of HSPT0 and HO-1 mRNA and protein in renal tissues. The blood samples obtained at T3 were used to determine serum creatinine （Cr） and urea nitrogen （BUN） concentrations and the expression of caspase-3 mR- NA. The apoptosis in the renal tissues was detected using TUNEL and apoptotic index （AI） was calculated. Microscopic examination was performed with light microscope. Results Compared with group S, the serum Cr and BUN concentrations and AI were significantly increased at T3, the expression of caspase-3 mRNA was up-regulated at T3 , and the expression of HSP70 and HO-1 mRNA and protein was up-regulated at T0-6 in the other groups （ P 〈 0.05）. Compared with group I/R, the serum Cr and BUN concentrations and AI were significantly decreased at T3, the expression of caspase-3 mRNA was down-regulated at T3, and the expression of HSP70 and HO-1 mRNA and protein was up-regulated at T1-5 in group IPo （P 〈 0.05）. Compared with group IPo, the serum Cr and BUN concentrations and AI were significantly increased at T3, the expression of caspase-3 mRNA was up-regulated at T3, and the expression of HSP70 and HO-1 mRNA and protein was down-regulated at T1-5 in group Q ＋ IPo （ P 〈 0. 05）. The microscopic examination showed that the renal I/R injury was significantly attenuated by ischemic postconditioning and the degree of injury in group IPo was similar to that in group I/R. Conclusion The expression of HSP70 and HO-1 is involved in the reduction of renal I/R injury by ischemic postconditioning in rats. Key words: HSP70 heat-shock proteins; Heme oxygenase-1; Renal; Reperfusion injury; Ischemic postconditioning

Suplementação infrequente e fontes proteicas para recria de bovinos em pastejo no período seco: parâmetros nutricionais

Objetivou-se com este estudo avaliar os efeitos de fontes proteicas e da frequência de fornecimento de suplemento sobre o consumo e a digestibilidade dos nutrientes, as concentrações de nitrogênio amoniacal (N-NH3), o pH ruminal e o nitrogênio ureico no soro de bovinos recriados em pastagem de Brachiaria brizantha cv. Marandu no período seco. Foram utilizados cinco novilhos mestiços Nelore × Angus fistulados no rúmen, castrados, com peso médio inicial de 295 kg em um delineamento quadrado latino 5 × 5. Avaliaram-se dois suplementos isoproteicos, um com farelo de soja (FS) e outro com farelo de algodão de alta energia, fornecidos em duas frequências: diariamente (7 vezes por semana) e 3 vezes por semana (segundas, quartas e sextas-feiras); e mistura mineral (MM). A suplementação aumentou o consumo de PB, extrato etéreo (EE) e carboidratos não-fibrosos (CNF), em kg/dia. O suplemento com farelo de algodão o consumo de extrato etéreo. Houve efeito positivo da suplementação 3 vezes por semana sobre os consumos de matéria seca total, de forragem, de matéria orgânica de forragem, carboidratos totais (CT) e FDN. A suplementação reduziu a digestibilidade da FDN e aumentou a de PB. O suplemento com farelo de algodão reduziu a digestibilidade de FDN e carboidratos totais. A suplementação 3 vezes por semana não afetou a digestibilidade dos nutrientes nem o pH ruminal. O consumo de suplemento aumenta as concentrações de N-NH3, principalmente se realizado 3 vezes por semana. As concentrações de nitrogênio ureico no soro de bovinos em pastejo aumentam com o consumo de suplementos.

Podolian beef production on pasture and in confinement

From February to August 2007 the effect of rearing system (confined (C) v. free ranging (FR)) and season (spring v. summer) was evaluated on behaviour, immune and blood parameters and beef production (experiment 1). From February to August 2008, the effect of rearing system was only evaluated on beef production (experiment 2). A total of 12 Podolian young bulls were used each year. They were slaughtered at 18 and 15 months of age in 2007 and 2008, respectively. Herbage mass and pasture composition were monitored during the 2 years. Pasture availability, in terms of herbage mass and composition, as well as its seasonal development, was similar in the 2 years. In the first experiment, FR animals spent more time walking (P < 0.05), feeding (P < 0.001) and standing (P < 0.01) and showed a lower number of agonistic (P < 0.05) and non-agonistic social interaction than C animals (P < 0.01). Significant lower concentrations of serum urea nitrogen (P < 0.001) and creatinine (P < 0.10) in FR animals indicated a lower protein nutritional status due to inadequate protein availability at pasture. As a consequence, average daily gains (P < 0.05), slaughter weight (P < 0.05) and body condition score (P < 0.01) were lower in grazing animals as compared with C bulls. Cellular immune responsiveness was higher in FR animals (P < 0.05). Similarly, antibody titre to keyhole limpet hemocyanin was higher in FR bulls at the 2nd and 3rd month after antigen injection (P < 0.05), whereas it tended to be higher at the 4th month (P < 0.10). In both experiments, grazing negatively affected meat colour in terms of lightness. Eighteen-month-old bulls also showed lower final weight, weight gain and body conditions when kept outdoor: a possible consequence of nutrient deficits, as suggested by the metabolic status of FR animals. The same animals, however, benefited from FR in terms of natural behaviour expression and immune responsiveness. When the experiment was replicated the subsequent year, on animals slaughtered at 15 months of age, no differences between the performances of FR and C animals were detected. The earlier slaughter age system was also proportionally less dependent on external inputs as grazing was not extended to the dry season when herbage mass availability was lower.

Cytoglobin, a Novel Member of the Globin Family, Protects Kidney Fibroblasts against Oxidative Stress under Ischemic Conditions

Cytoglobin (Cygb) is a novel member of the vertebrate globin superfamily. Although it is expressed in splanchnic fibroblasts of various organs, details of its function remain unknown. In the present study, kidney ischemia-reperfusion (I/R) increased the number of Cygb-positive cells per area and up-regulated Cygb mRNA and protein expression in kidney cortex tissues. Similarly, hypoxia up-regulated Cygb expression in cultured rat kidney fibroblasts. The biological function of Cygb in vivo was evaluated in Cygb-overexpressing transgenic rats. Renal dysfunction and histologic damage after renal I/R were ameliorated (mean [SE] serum urea nitrogen concentration after I/R injury, 260.6 [44.9] mg/dL in wild-type rats versus 101.0 [36.0] mg/dL in transgenic rats; P < 0.05) in association with improvement of oxidative stress. Primary cultured fibroblasts from Cygb transgenic rat kidney were resistant to exogenous oxidant stimuli, and treatment of immortalized kidney fibroblasts with Cygb-small interfering RNA (siRNA) enhanced cellular oxidant stress and subsequently decreased cell viability (cell count ratio after exposure to hydrogen peroxide, 35.9% [1.6%] in control-siRNA-treated cells versus 25.5% [2.0%] in Cygb-siRNA-treated cells; P < 0.05). Further, chemical or mutant disruption of heme in Cygb impaired its antioxidant properties, which suggests that the heme of Cygb per se possesses a radical scavenging function. These findings show for the first time, to our knowledge, that Cygb serves as a defensive mechanism against oxidative stress both in vitro and in vivo.