Tear urea nitrogen and creatinine levels in horse and their correlation with serum values

The objective of this paper was to determine the physiological values of urea nitrogen and creatinine in tears, and to compare the results with those obtained from serum. Thirty healthy thoroughbred horses were included in the study. Tear fluid samples were obtained using a glass capillary tube placed in lower conjunctival cul-de-sac. Blood samples were taken from the jugular vein. Tear and serum urea nitrogen and creatinine levels were quantitatively analyzed by an enzymatic colorimetric method. Urea nitrogen values were 4.22+/-1.84 mmol/l in tears and 4.44+/-1.78 mmol/l in serum, whereas creatinine values in tears were 14.14+/-7.74 micromol/l and in serum 147.63+/-12.17 micromol/l. Statistical analysis confirmed a significant correlation between serum and tear urea levels (P<0001). However, there was no significant correlation between blood and tear creatinine values. Mean value of creatinine obtained from tears was 9.6% of the mean value from serum. Urea nitrogen and creatinine levels can be measured in tears. A significant correlation was found between serum and tears urea levels. This finding may permit development of a new alternative laboratory diagnosis of uremia based on the content of urea in tears.     

Association of gastrointestinal hemorrhage with increased blood urea nitrogen and BUN/creatinine ratio in dogs: a literature review and retrospective study

Blood urea nitrogen (BUN) and serum creatine concentrations were recorded from the medical records of 52 dogs with clinical evidence for upper gastrointestinal hemorrhage (UGH) at the Colorado State University Veterinary Teaching Hospital between 1988 and 1995. Eighteen of the dogs had melena, 11 dogs had hematemesis, and 23 dogs had both melena and hematemesis. Compared with age-matched control dogs, dogs with suspected UGH had a significantly higher BUN concentration (31.0 mg/dL vs. 16.5 mg/dL), creatinine concentration (1.2 mg/dL vs. 1.1 mg/dL) and BUN/creatinine ratio (27.6 vs. 14.4). The increase in BUN/creatinine ratio suggested that the increased BUN concentration in dogs with evidence for UGH primarily was associated with increased gastrointestinal absorption of nitrogenous compounds, and hepatic ureagenesis.     

Effect of specimen collection and storage on blood glucose and lactate concentrations in healthy,hyperthyroid and diabetic cats

Abstract: The objective of this study was to compare and investigate differences in glucose and lactate concentrations in sodium fluoride/potassium oxalate (NaF/Ox) plasma and serum in healthy cats and cats with metabolic disease. Glucose and lactate concentrations were determined in routinely processed serum and NaF/Ox plasma obtained from healthy (n = 30), hyperthyroid (n = 27) and diabetic (n = 30) cats, and in samples from 6 healthy cats stored at 25°C or 4°C for 0,1, 2, 4, or 8 hours. The packed cell volume (PCV) of blood collected in NaF/Ox was compared with that of blood collected in EDTA. Mean glucose concentration was significantly (P < .05) lower in NaF/Ox plasma than in serum in all groups of cats, by 0.7–2.5 mmol/L (11–45 mg/dL); the difference was greater in cats with hyperglycemia. Mean lactate concentration was significantly higher in serum than in NaF/Ox plasma in all groups of cats, by 0.4–1.2 mmol/L (3.6–10.8 mg/dL); the difference was greater in hyperthyroid and diabetic cats. In vitro, only serum stored on the clot for ≥ 1hour at 25°C had significantly lower glucose and higher lactate concentrations. The PCV of NaF/Ox-anticoagulated blood was lower than that of EDTA-anticoagulated blood, by 7.0%± 1.4% (P<.01). In conclusion, collection of feline blood in NaF/Ox was necessary to prevent in vitro increases in lactate concentration; however, NaF/Ox artifactually decreased plasma glucose concentration because of RBC shrinkage. The PCV should not be determined on blood collected in NaF/Ox.     

Comparison of measurements of canine plasma glucose, creatinine, urea, total proteins, alanine aminotransferase, and alkaline phosphatase obtained with the APOLOWAKO and Vitros 250 analyzers

The APOLOWAKO is an entirely automatic benchtop biochemistry analyzer that uses stabilized liquid reagents. It was tested for canine blood and plasma glucose, creatinine, urea, total proteins, alanine aminotransferase, and alkaline phosphatase. The APOLOWAKO gave very similar results for whole blood and the corresponding plasma (n=32). Within-laboratory imprecision was below 2.2% and 5.8% for substrates and enzymes, respectively. Comparison of results with whole blood by APOLOWAKO and with the corresponding plasma by Vitros 250 (n=139) showed very good correlations. Passing-Bablok's regression slopes ranged from 0.83 to 1.12 and intercepts were close to zero, except for ALP where the results obtained by APOLOWAKO were approximately 1.5 times higher than by Vitros. The APOLOWAKO system can be a reliable instrument in veterinary practices where larger systems are not available but it should be further validated and reference intervals should be determined.     

青贮紫花苜蓿对奶牛生产性能、尿素氮和血液生化指标的影响

在苜蓿（Medicago sativa）中添加5%的糖蜜,并进行苜蓿大窖青贮和饲喂试验,研究以青贮苜蓿（试验组）替代相同干物质量（DM）的苜蓿干草（对照组）对奶牛生产性能、尿素氮及血液生化指标的影响。结果表明,给奶牛饲喂苜蓿青贮饲料有利于提高奶牛干物质采食量（Dry Matter Intake,DMI）、日产奶量和乳脂率,试验后期乳蛋白含量有所下降,但差异均不显著（P0.05）;乳尿素氮（Milk Urea Nitrogen,MUN）及尿液尿素氮（Urinary Urea Nitrogen,UUN）含量均呈现下降趋势,血浆尿素氮（Plasma Urea Nitrogen,BUN）先下降后上升,其中试验组MUN和BUN低于对照组（P0.05）,UUN则高于对照组,在试验后期,试验组和对照组UUN分别为48.35和27.52 mmolL-1,差异显著（P0.05）;谷丙转氨酶（Alanine Aminotransferase,ALT）、谷草转氨酶（Aspartate Transaminase,AST）和碱性磷酸酶（Alkaline Phosphatase,ALP）含量均为试验组高于对照组,差异不显著（P0.05）;血浆中总蛋白（Albumin,ALB）和葡萄糖（Glucose,GLU）含量试验组逐渐降低,且低于对照组,但差异不显著（P0.05）;胆固醇（Chinese Hamster Ovary,CHO）的含量试验组逐渐升高,对照组逐渐降低,在试验后期分别为3.64和2.82 mmolL-1（P=0.059）,差异最大。总之,饲喂苜蓿青贮饲料有利于改善奶牛的生产性能和机体代谢能力,由于美拉德反应的发生,试验后期降低了苜蓿青贮饲料营养物质在奶牛体内的代谢利用效果。     

Comparison of glucose concentrations in canine whole blood,plasma, and serum measured with a veterinary point-of-care glucometer

Previous studies have determined that, compared to whole blood, serum or plasma used in a portable blood glucometer (PBG) may provide more accurate results. We investigated the accuracy of a veterinary PBG (AlphaTRAK 2; Zoetis) for the measurement of glucose concentrations in serum, plasma, and whole blood compared to plasma glucose concentration measured by a biochemical analyzer. Blood samples from 53 client-owned dogs were collected. Lin concordance correlation coefficient (ρ_c) and Bland–Altman plots were used to determine correlation and agreement between the results obtained for the different sample types. Glucose concentration in whole blood measured by the veterinary PBG was more strongly correlated with the glucose concentration measured by the biochemical analyzer (ρ_c = 0.92) compared to plasma and serum glucose concentrations (ρ_c = 0.59 and 0.57, respectively). The mean differences between the glucose concentrations in whole blood, plasma, and serum measured by the veterinary PBG and the glucose concentration determined by the biochemical analyzer were 1.0, 6.3, and 6.7 mmol/L (18, 113, and 121 mg/dL), respectively. Our findings suggest that, when using this veterinary PBG, the accuracy of a glucose measurement obtained is higher when using whole blood compared to plasma or serum. Use of whole blood allows for more correct assessment and diagnosis, which are necessary for appropriate therapeutic intervention.     

Comparison of measurements of canine plasma creatinine, glucose, proteins, urea, alanine aminotransferase, and alkaline phosphatase obtained with Spotchem SP 4430 and Vitros 250 analyzers

The suitability of the Spotchem 4430 benchtop biochemistry analyzer for canine blood samples was tested for creatinine, glucose, proteins, urea, alkaline phosphatases and alanine aminotransferase. Results obtained from whole blood and corresponding heparin plasma were identical except for proteins which were higher in plasma (n=10). Between series imprecision (n=10) was <5% for substrates and <10% for enzymes. Comparison of results from 100 Li-heparin samples with those measured with a Vitros 250 analyzer showed good correlation (r>0.93). The slopes of the Passing-Bablock's regression ranged from 0.90 to 1.20 and intercepts were low. The mean biases were low, except for creatinine for which the results obtained by Spotchem (Jaffe reaction) were about 20 micromol/L higher than with the Vitros (enzymatic reaction). The results of this study show that the Spotchem analyzer is suitable for use in canine whole blood or plasma when small numbers of tests are to be performed and large analyzers are not available.     

小肽对山羊门静脉血糖血氨和血浆氨基酸浓度的影响

采用随机区组重复试验设计,选取6只浏阳黑山羊分成2组,灌注小肽的为试验组,灌注水解氨基酸的为对照组,经门静脉插管采集血样进行分析。结果表明,对照组和试验组山羊在采食后6个时间点的平均血糖浓度分别为2.82±0.27和3.51±0.15 mmol/L,试验组血糖浓度显著高于对照组(P<0.05);血氨浓度分别为0.235±0.09和0.252±0.08 mmol/L,2组差异不显著(P>0.05);门静脉血浆中苏氨酸、丙氨酸和精氨酸的浓度试验组极显著地高于对照组(P<0.01);丝氨酸、甘氨酸、蛋氨酸、缬氨酸、亮氨酸和酪氨酸的浓度试验组显著高于对照组(P<0.05);而其它氨基酸的浓度无显著差异。这说明小肽能促进山羊对血糖和部分氨基酸的吸收,而对血氨的吸收无明显影响。     

复合酵母培养物对奶牛产奶性能、氮排放及血液生化指标的影响

为研究饲料中添加复合酵母培养物对奶牛产奶性能、氮排放及血液生化指标的影响,选取年龄、体重、产奶量及泌乳期相近(135±15) d的荷斯坦奶牛24头,随机分为4组,每个处理6个重复,对照组和3个试验组的复合酵母培养物添加量分别为精料浓度的0,0.8%,1.0%,1.2%,随精料饲喂,测定产奶量、乳成分、氮排放及血液生化指标,结果表明,1)试验2组日均产奶量显著高于对照组(P<0.05),各试验组分别比对照组提高8.48%,10.05%,8.97%。2)复合酵母培养物能显著提高乳脂和乳蛋白率(P<0.05),显著降低牛奶体细胞数(P<0.05),以试验2组最低。3)在氮排放量上,试验2组显著低于对照组(P<0.05),各试验组比对照组分别降低8.47%,12.01%,9.36%。4)在血液生化指标方面,复合酵母培养物能提高血清中总蛋白、球蛋白、血糖、胰岛素水平(P<0.05),降低尿素氮水平(P<0.05)。由此可见,本试验条件下,综合考虑产奶量、乳成分、氮排放及血液生化指标,复合酵母培养物的最佳添加量为精料浓度的1.0%。     

Associations between meal size,gastric emptying and post‐prandial plasma glucose,insulin and lactate concentrations in meal‐fed cats

Plasma glucose and insulin concentrations are increased for 12–24 h in healthy cats following moderate‐ to high‐carbohydrate meals. This study investigated associations between gastric emptying time and post‐prandial plasma glucose, insulin and lactate concentrations in cats fed an extruded dry, high‐carbohydrate, moderate‐fat, low‐protein diet (51, 28, 21% metabolizable energy, respectively) once daily by varying meal volume. Eleven healthy, non‐obese, neutered adult cats were enrolled in a prospective study and fed to maintain body weight. Ultrasound examinations were performed for up to 26 h, and blood collections over 24 h after eating meals containing approximately 100% and 50% of the cats’ daily caloric intake (209 and 105 kJ/kg BW, respectively). Gastric emptying time was increased after a meal of 209 kJ/kg BW compared with 105 kJ/kg BW (median gastric emptying times 24 and 14 h, respectively; p = 0.03). Time for glucose to return to fasting was longer after the 209 kJ/kg BW meal (median 20 h; 25th and 75th percentiles 15 and 23 h, respectively) than the 105 kJ/kg BW meal (13, 12 and 14 h; p < 0.01); however, peak glucose was not higher after the 209 kJ/kg BW meal compared with the 105 kJ/kg BW meal [(mean ± SD) 6.6 ± 0.6 and 7.8 ± 1.2 mmol/l, respectively, p = 0.07]. Times for insulin to return to fasting were not significantly longer after the 209 kJ/kg BW meal than the 105 kJ/kg BW meal (p = 0.29). d ‐ and l ‐lactate concentrations were not associated with gastric emptying time or post‐prandial blood glucose and insulin. Based on results obtained, prolonged gastric emptying contributes to prolonged post‐prandial hyperglycemia in cats meal fed a high‐carbohydrate, low‐protein, dry diet and fasting times for cats’ meal‐fed diets of similar composition should be 14–26 h, depending on meal size.     

Serum IgM concentrations in normal,fit horses and horses with lymphoma or other medical conditions

The purposes of this study were to (1) prospectively establish serum IgM and IgG concentrations in normal, fit, adult horses over time and (2) determine the accuracy of serum IgM concentrations for diagnosing lymphoma. Serial IgM and IgG concentrations were measured with a radial immunodiffusion assay in 25 regularly exercised horses at 6-week intervals. Horses had serum IgM concentrations ranging from 50 to 242 mg/dL over 5 months, with 20% of horses having IgM < or = 60 mg/dL. The normal range for IgM in fit horses should be considered 103 +/- 40 mg/dL and a cut-point for an IgM deficiency, < or = 23 mg/dL. IgG concentrations ranged from 1,372 to 3,032 mg/dL. Retrospectively, medical records of adult horses (n = 103) admitted to the Cornell University Hospital for Animals for which serum IgM was measured were examined. Horses were categorized as "lymphoma negative" (n = 34) or "lymphoma positive" (n = 18). The sensitivity and specificity of a serum IgM concentration (< or = 60 mg/dL) for detecting equine lymphoma was 50 and 35%, respectively. At the new cut-point (< or = 23 mg/dL), the sensitivity was low at 28% and the specificity improved to 88%. The negative predictive values at various population prevalences indicate that a horse with a high serum IgM (> 23 mg/dL) is unlikely to have lymphoma, whereas the positive predictive value (70%) does not allow for reliable determination of lymphoma in a horse with serum IgM < or = 23 mg/dL. Therefore, serum IgM concentrations should not be used as a screening test for equine lymphoma.     

日粮不同锌添加水平对育成期雄性水貂消化代谢、生长性能和血清生化指标的影响

本试验选用硫酸锌和蛋氨酸螯合锌两种锌源,在日粮添加60 mg/kg硫酸锌、蛋氨酸螯合锌为0、15、30、45、60、75 mg/kg 水平下,对比研究了不同锌水平对育成期雄性水貂营养物质消化率、氮代谢和血清生化指标的影响。结果表明,育成期雄性水貂日粮中添加15 mg/kg的蛋氨酸螯合锌时,水貂采食量和蛋白质消化率较高(P<0.05)。日粮中添加锌水平对水貂干物质消化率、脂肪消化率、氮代谢、生长性能和血清尿素氮、血清乳酸脱氢酶活性没有显著性影响(P>0.05)。     

Effect of octreotide on plasma concentrations of glucose, insulin, glucagon, growth hormone, and cortisol in healthy dogs and dogs with insulinoma

The inhibitory effect of the somatostatin analogue octreotide on the secretion of insulin could be used in the treatment of insulinoma. However, current information on the effectiveness of octreotide in dogs is conflicting. Therefore, the endocrine effects of a single subcutaneous dose of 50 microg octreotide were studied in healthy dogs in the fasting state (n=7) and in dogs with insulinoma (n=12). Octreotide did not cause any adverse effects. In healthy dogs in the fasting state, both plasma insulin and glucagon concentrations declined significantly. Basal (non-pulse related) GH and ACTH concentrations were not affected. A slight but significant decrease in the plasma glucose concentrations occurred. Dogs with insulinoma had significantly higher baseline insulin concentrations and lower baseline glucose concentrations than healthy dogs in the fasting state. Plasma glucagon, GH, ACTH, and cortisol concentrations did not differ from those in healthy dogs. Baseline plasma insulin concentrations decreased significantly in dogs with insulinoma after octreotide administration, whereas plasma concentrations of glucagon, GH, ACTH, and cortisol did not change. In contrast to the effects in the healthy dogs, in the dogs with insulinoma plasma glucose concentrations increased. Thus, the consistent suppression of plasma insulin concentrations in dogs with insulinoma, in the absence of an suppressive effect on counter-regulatory hormones, suggests that further studies on the effectiveness of slow-release preparations in the long-term medical treatment of dogs with insulinoma are warranted.     

Circannual variation in plasma adrenocorticotropic hormone concentrations in the UK in normal horses and ponies, and those with pituitary pars intermedia dysfunction

Reasons for performing study: Pituitary pars intermedia dysfunction (PPID) is a common endocrinopathy, frequently diagnosed via plasma adrenocorticotropic hormone (ACTH) concentrations. Seasonal variation in plasma ACTH concentrations has been described in normal horses prompting caution in diagnosing PPID at certain times of the year. The aims of this study were to determine appropriate reference intervals for equine plasma ACTH throughout the year; and to examine the circannual variation of plasma ACTH concentrations in PPID cases. Hypothesis: Plasma ACTH can be used as a test for PPID throughout the year with the use of appropriate reference intervals. Methods: Data for reference interval calculations were obtained from samples collected from inpatients of Liphook Equine Hospital (non‐PPID group, n = 156). Data from PPID cases (n = 941) were obtained from samples submitted to the Liphook Equine Hospital Laboratory from horses with a clinical suspicion of PPID found to have plasma ACTH concentrations greater than our upper reference interval for that time of year. Results: Upper limits for reference interval of plasma ACTH were 29 pg/ml between November and July and 47 pg/ml between August and October. Circannual variation in plasma ACTH occurred in both non‐PPID and PPID horses with the highest ACTH concentrations found between August and October in both groups (P<0.0001). The greatest difference between the 2 populations also occurred between August and October. Conclusions: Plasma ACTH can be used for the diagnosis and monitoring of PPID throughout the year with the use of appropriate reference intervals. These findings demonstrate an increase in pituitary gland secretory activity during the late summer and autumn in both normal and PPID cases.     

The content of Hb and the hematocrit value in blood and the total proteins, urea, glucose, free fatty acids, Na, K, Ca, Mg, Pa, Fe, Fe-binding capacity, Cu and Zn in the blood plasma of Warmblood horses during feeding with oat-hay or barley-hay rations over a period of 9 months

4 horses (Group A) received an oat-hay ration, through 9 months running, while 3 horses (Group B) were fed a barley-hay ration over the same period of time. Blood samples were collected and examined in 4-week intervals. All values considered, no differences were found to exist between the 2 groups with regard to Hb and haematocrit in blood as well as to protein, glucose, sodium, potassium, magnesium, iron fixation capacity, copper, and zinc in blood plasma. The urea level in plasma of Group A was higher than that in Group B, values being 5.76 +/- 0.64 mmol/l and 5.14 +/- 0.72 mmol/l. The same applied to free fatty acids, values being 150 +/- 83 mumols/l in Group A and 95 +/- 42 mumols/l in Group B. Calcium was 3.10 +/- 0.27 mmol/l in Group A and 2.92 +/- 0.26 mmol/l in Group B, while the A-B difference in inorganic phosphorus amounted to 1.62 +/- 0.65 against 1.99 +/- 0.77 mmol/l. Group A was inferior to Group B also with regard to iron in plasma, values being 28.6 +/- 2.42 mumols/l against 32.8 +/- 4.62 mumol/l. Causes underlying these differences are discussed in some detail.