Changes in activities of enzymes related to energy metabolism in peripheral leukocytes of diabetic dogs with glycemic control by intensive insulin treatment

Changes in plasma glucose, immunoreactive insulin (IRI), and free fatty acids (FFA) concentrations and activities of enzymes related to energy metabolism in peripheral leukocytes were measured in type 1 diabetic dogs induced by streptozotocin administration before and after intensive insulin treatments. Before the insulin treatment, the plasma glucose concentrations were over 16.7 mmol/L and the activities of enzymes remarkably decreased in leukocytes of the diabetic dogs. In particular, malate dehydrogenase (MDH) activities decreased significantly. After glycemic control was achieved by insulin treatment, the plasma glucose concentrations were maintained between 6.8 and 7.7 mmol/L and the activities of enzymes restored to those in the control dogs. The changes in ML ratio (cytosolic MDH/lactate dehydrogenase specific activity ratio) reflected faithfully to metabolic conditions of animals and were considered to be a useful parameter to evaluate glycemic control and the effect of injected insulin in the diabetic dogs.     

Thymoquinone enhances the activities of enzymes related to energy metabolism in peripheral leukocytes of diabetic rats

The aim of this study was to examine the effect of glycemic control using thymoquinone (TQ) on energy metabolism related enzymes in leukocytes of streptozotocin (STZ)-induced diabetic rats. The treatment of both TQ and insulin commenced 4 weeks after induction of diabetes. Plasma glucose, cholesterol and triglycerides levels were significantly reduced after TQ treatment, whereas immunoreactive insulin (IRI) showed significant increase. The activities of malate dehydrogenase (MDH) in cytosolic and mitochondrial fractions of peripheral blood leukocytes were significantly higher in rats treated with TQ and insulin as compared to that in diabetic controls. On the other hand the activities of lactic dehydrogenase (LDH) showed no significant changes between groups. ML ratio (cytosolic MDH/LDH specific activity ratio) was restored to those in the control rats. The results of this study demonstrate that TQ significantly increased insulin level and the activities of cytosolic and mitochondrial MDH in leukocytes of STZ-diabetic rats.     

A comparison of the activities of certain enzymes related to energy metabolism in leukocytes in dogs and cats

The activities of Na>⁺,K>⁺-ATPase in plasma membrane, of cytosolic enzymes and of glutamate dehydrogenase (GlGD) in mitochondria were measured in leukocytes (WBC) from dogs and cats to clarify the differences in energy metabolism in these cells. Feline WBC had significantly higher activities of hexokinase (HK), pyruvate kinase (PK) and LDH with pyruvate as substrate than did canine WBC. Canine WBC had significantly higher activities of glucokinase (GK) and GlDH than did feline WBC. Feline WBC had unique characteristics of energy metabolism in that the activities of the cytosolic enzymes under anaerobic conditions were significantly higher than those in canine WBC. It therefore appears that there are distinct differences in glucose metabolism in WBC between dogs and cats. WBC enzyme activities are considered to reflect the metabolic state in the whole body of the animal. It is therefore suggested that changes in the activities of certain glycolytic enzymes in WBC may be useful as a diagnostic indicator in some types of metabolic disease in dogs and cats.     

Changes in activities of enzymes related to malate-aspartate shuttle in leukocytes from dogs given a herb supplement.

Changes in activities of enzymes related to the malate-aspartate shuttle were measured in leukocytes (WBC) from dogs given food supplemented with 2 mg/kg of herb powder, Echevaria glauca, every day for 4 weeks. There were no significant differences in plasma concentrations of glucose, immunoreactive insulin, free fatty acids and triglyceride between dogs given food with or without the herb supplementation. Activities of malate dehydrogenase (MDH) and aspartate aminotransferase (AST) in the malate-aspartate shuttle increased remarkably in mitochondria of WBC from dogs fed the herb supplementation. It is suggested that Echevaria glauca herb supplementation might activate NADH shuttle systems and mitochondrial energy metabolism in dogs.     

CD20 expression in normal canine B cells and in canine non-Hodgkin lymphoma

We examined the expression of CD20 in normal canine peripheral blood mononuclear cells, normal canine spleen, and canine non-Hodgkin lymphoma (NHL) to determine the feasibility of using this antigen as a diagnostic aid and as a possible target for therapy. An antibody generated against a C-terminal (intracytoplasmic) epitope of human CD20 recognized proteins of 32-36 kd in normal and malignant canine lymphocytes. This antibody showed restricted membrane binding in a subset of lymphocytes in peripheral blood, in the B-cell regions from a normal canine spleen and lymph node, and in malignant cells from 19 dogs with B-cell NHL, but not from 15 dogs with T-cell NHL. The patterns of CD20 reactivity in these samples overlapped those seen using an antibody that recognizes canine CD79a. This anti-CD20 antibody is therefore suitable as an aid to phenotype canine NHL. In contrast, normal canine B cells were not recognized by any of 28 antibodies directed against the extracellular domains of human CD20 (including the chimeric mouse-human antibody Rituximab) or by any of 12 antibodies directed against the extracellular domains of mouse CD20. Thus, the use of CD20 as a therapeutic target will require the generation of specific antibodies against the extracellular domains of canine CD20.     

四季鹅胃肠道发育及消化酶活力的年龄性变化

四季鹅于放牧及补喂稻谷条件下,从1日至10周龄,每隔两周宰杀10～12只。胃肠道发育及消化酶活力的年龄性变化表明,鹅的消化器官比其它器官率先发育,但2周龄后,消化道占体重比率逐步下降。鹅的肌胃及其食糜重量占胃肠道比例自始至终最大;2周龄时肌胃食糜出现砂砾,9周龄即占肌胃食糜的60％左右。盲肠发育较迟,2周龄时出现微生物消化,食糜已有较高总脱氢酶活力(1395u/100g),挥发性脂肪酸(VFA)含量达5.63mM/100g,随年龄增长,由乙酸型发酵向丙酸型发酵转变。但盲肠食糜量较少,对整个消化过程似无重要意义。1 日龄胰腺已有相当高蛋白酶(1141u/g)和淀粉酶活力(1111.39u/g),后者随年龄增长呈直线增高。     

温度胁迫对亚热带常用草坪草活性氧代谢相关酶的影响

研究了在高温和低温胁迫下,亚热带建坪常用草坪草叶片的活性氧代谢相关酶与细胞膜透性的变化,并依据"自由基"假说,探讨了温度胁迫条件下自由基对草坪草细胞(主要是细胞膜体系)的伤害机理,初步揭示了不同温度胁迫下草坪草受害的致成原因以及不同品种间的差异.研究结果表明,以活性氧代谢指标与细胞膜透性为评判抗性大小的依据,各类品种的抗寒性大小顺序是匍匐剪股颖Agrostis stolonifere>草地早熟禾Poa pratensis>多年生黑麦草Lolium perenne>高羊茅Festuca arundinacea>狗牙根Cynodon dactylon,抗热性大小顺序是狗牙根 > 高羊茅 > 草地早熟禾 > 多年生黑麦草 > 匍匐剪股颖.研究运用了亚热型草坪草活性氧代谢相关酶测定的方法进行了草坪草品种鉴定和抗性比较,为亚热带地区草坪草品种选择、建植和维护提供了科学的理论依据.     

Changes in metabolite, energy metabolism related enzyme activities and peripheral blood mononuclear cell (PBMC) Populations in beef heifers with two differing liveweight change profiles in New Zealand

Metabolite and immunoreactive insulin (IRI) concentrations, energy metabolism related enzymes activities and peripheral blood mononuclear cell (PBMC) populations were measured in blood of pregnant Angus heifers with differing liveweight change profiles (gaining or losing), in New Zealand to investigate the meanings of those parameters in the restricted feeding beef heifers. Beef heifers losing liveweight (−412 g/day) showed significantly lower concentrations of plasma IRI, and higher concentrations of plasma free fatty acid (FFA) than heifers gaining liveweight (483 g/day). The cytosolic and mitochondrial malate dehydrogenase (MDH) activities and MDH/lactate dehydrogenase (M/L) ratio in leukocytes of the liveweight losing heifers were significantly higher than those the liveweight gaining heifers. Percentages of cluster of differentiation (CD) 3 positive cells and natural killer (NK) cells in PBMC decreased significantly in the liveweight losing heifers compared to those in the liveweight gaining heifers. Plasma IRI and FFA concentrations, leukocyte cytosolic and mitochondrial MDH activities and CD3 positive and NK cell populations may be useful markers to evaluate metabolic conditions and immunity in the restricted feeding beef heifers.     

柑橘褐斑病菌对不同抗性柑橘品种防御酶活性的影响

以柑橘褐斑病高抗品种Lw8,中抗品种L2,高感品种Lw14为实验材料,通过孢子喷雾法使柑橘褐斑病菌感染柑橘叶片,研究接菌0d、1d、2d、3d、6d、8d、10d时,柑橘叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)、几丁质酶(CHT)酶和β-1,3葡聚糖酶(GLU)含量及活性变化规律与品种抗病性的关系。结果表明,接种前,两个抗病品种Lw8、L2中的POD、SOD、PAL、PPO 、GLU、CHT活性显著高于高感品种Lw14,CAT活性则与高感品种Lw14相近;接种后,3个不同抗性品种中SOD、POD、CAT、PAL、PPO 、GLU、CHT 7种防御酶活性较对照明显提高,但不同品种增加幅度不一致,除CAT外,其余6种防御酶活性均表现为抗病品种Lw8、L2增幅显著高于高感品种Lw14,且两个抗病品种一般在接菌3d内6种防御酶活性迅速升高并达到峰值;而高感品种Lw14防御酶(除CAT外)活性或增幅较小或较两个抗病品种滞后。本研究初步探讨了不同抗性品种接种褐斑病菌后7种防御酶的活性动态变化与柑橘品种抗病性关系,为进一步研究其抗病机理奠定基础。     

Flubendazole metabolism and biotransformation enzymes activities in healthy sheep and sheep with haemonchosis

Bártíková, H., Křížová, V., Lamka, J., Kubíček, V., Skálová, L., Szotáková, B. Flubendazole metabolism and biotransformation enzymes activities in healthy sheep and sheep with haemonchosis. J. vet. Pharmacol. Therap . 33 , 56–62.
The aim of this project was to study the influence of haemonchosis, a common parasitic infection of small ruminants caused by Haemonchus contortus , on the activity of biotransformation enzymes and on in vitro flubendazole (FLU) biotransformation in liver and small intestine of lambs ( Ovis aries ). Twelve lambs were divided into three groups: non-infected animals, animals orally infected with larvae of H. contortus ISE strain for 7 weeks and for 11 weeks. At the end of the experiment, hepatic and intestinal subcellular fractions were prepared and used for assays of biotransformation enzymes activities and FLU metabolism testing. The activities of hepatic cytochromes P450, flavine monooxygenases and carbonyl-reducing enzymes were decreased in infected animals. UDP-glucuronosyl transferase activity was significantly lower (by 35%) in 11 weeks infected animals than that in control animals. When in vitro metabolism of FLU was compared in control and infected animals, significantly lower velocity of FLU reduction was found in infected animals. Slower FLU reduction may be beneficial for the haemonchosis treatment using FLU, because FLU will remain longer in the organism and could cause longer contact of parasites with FLU.     

Changes in energy metabolism in relation to physical activity due to fermentable carbohydrates in group-housed growing pigs

Fermentable nonstarch polysaccharides (dietary fiber) affect energy retention in group-housed growing pigs by reducing physical activity. This study assessed the effects of fermentation and bulkiness of dietary carbohydrates on physical activity in relation to energy metabolism. Eight clusters of 14 pigs were fed one of four diets in a 2x2 factorial arrangement. Factors included 1) gastrointestinal fermentation and 2) dietary bulkiness. Contrasts in fermentation were created by exchanging gelatinized maize starch with raw potato starch on a volume basis. Bulkiness was altered by adding 15% milled wheat straw to the diets. Apart from these differences, amounts of other dietary ingredients fed to the pigs were similar. Pigs were housed in groups. Nitrogen and energy balances were measured per cluster during a 14-d period. Dietary bulkiness did not affect ME intake, heat production, or energy retention. Metabolizability decreased when maize starch was replaced with raw potato starch (P< .01), resulting in a lower energy retention on the potato starch diets (P<.01). However, the lower ME intake on the potato diets was partially compensated by a reduced energy expenditure on physical activity (P< .01), which was 17.6% lower than that of pigs fed the maize starch diets. Dietary bulkiness did not affect physical activity. The effect of fiber-rich diets (nonstarch polysaccharides) on activity in growing group-housed pigs seems to be related to fermentation in the gastrointestinal tract, and not to bulkiness (volume).     

In vitro metabolism of progesterone by canine hair follicle cells

Dermal papilla cells (DPC) and dermal fibroblasts (DFB) derived from hair follicles from two different body sites (head, flank) of four male, castrated beagle dogs were incubated for 24 h with radioactive progesterone (P4). Thin-layer chromatography was used for separation and autoradiography for identification of the radioactive metabolites. In DFB the main metabolites were cortisol and 4-pregnene-11beta-ol-3,20-dione, whereas in DPC they were 5alpha-pregnane-3,20-dione and cortisol. The highest percentage of metabolism of P4 was found in DFB of the head. Smaller amounts of other metabolites were found in both cell types of both locations.     

Plasma parameters related to energy and lipid metabolism in periparturient Modenese and Italian Friesian cows

The aim of this work was to compare energy and lipid metabolism during the peripartum period between Modenese (MO) and Italian Friesian (IF) cows. The study was carried out on 33 pluriparous pregnant cows, 19 IF and 14 MO, reared together in the same herd and kept under equal conditions of management and nutrition. Blood was sampled from jugular vein starting 4 week before expected calving date until 4 week post‐calving, once weekly. Plasma was analysed for glucose, NEFA, BHBA, triglycerides and cholesterol concentrations. Body condition score (BCS) was assessed weekly after blood sampling. Data from antepartum (a.p.) and post‐partum (p.p.) periods were separately analysed as repeated measures by a linear mixed models with the effect of breed, time and their interaction as main factors and random cow within breed. The energy status differed between the two breeds during the peripartum period. We observed higher BCS a.p. and p.p. and lower BCS variations p.p. in MO compared to IF group. Modenese cows showed lower glucose and cholesterol concentrations (p < 0.001), but higher NEFA values, NEFA to cholesterol and NEFA to albumin ratios (p < 0.001) during a.p.; on the contrary, IF cows had higher (p < 0.05) cholesterol, NEFA, BHBA levels and NEFA to albumin ratio than MO ones during p.p. The differences observed between the two breeds suggest how MO cows are subjected to lipid mobilization during late gestation; on the contrary, IF cows are predisposed to mobilize their lipid reserves at the beginning of lactation to support high production. The results indicate a diverse ability to cope with metabolic stress and suggest the hypothesis that the differences in concentrations of plasma parameters and their variation amplitude around the calving period might depend on the different genetic merit for milk production between the two breeds.     

Xenobiotic-metabolizing enzymes in canine mammary tumours

Mammary tumours are the most common neoplasms in female dogs. The present study was designed to evaluate the relationship between different clinical stages with activities of phase I and phase II carcinogen-metabolizing enzymes in canine mammary tumours. The levels of cytochrome P450 and cytochrome b5 and the activities of glutathione S-transferase (GST), gamma-glutamyl transpeptidase (GGT), DT-diaphorase (DTD) and NADPH diaphorase in tumour tissues of 25 bitches was estimated. Enhanced levels of cytochrome P450 and b5 and phase II enzyme activities were observed in tumour tissues compared to the corresponding uninvolved adjacent tissues. The magnitude of the changes in phase I and phase II enzyme status was, however, more pronounced in stages I and II compared to stages III and IV. The results suggest that the balance between phase I carcinogen activation and phase II detoxification systems may play an important role in canine mammary tumour development.     

Expression of O6-methylguanine-DNA methyltransferase causes lomustine resistance in canine lymphoma cells

The DNA repair protein O⁶-methylguanine-DNA methyltransferase (MGMT) causes resistance to nitrosoureas in various human cancers. In this study, we analyzed the correlation between canine lymphomas and MGMT in vitro. Two of five canine lymphoma cell lines required higher concentrations of lomustine to inhibit cell growth by 50%, but their sensitivity to the drug increased when they were cultured with an MGMT inhibitor. Fluorometric oligonucleotide assay and real-time polymerase chain reaction of these cell lines revealed MGMT activity and high MGMT mRNA expression, respectively. We analyzed the methylation status of the CpG islands of the canine MGMT gene by the bisulfite-sequencing method. Unlike human cells, the canine lymphoma cell lines did not show significant correlation between methylation status and MGMT suppression levels. Our results suggest that in canine lymphoma MGMT activity may influence sensitivity to nitrosoureas; thus, inhibition of MGMT activity would benefit nitrosourea-resistant patients. Additional studies are necessary to elucidate the mechanism of regulation of MGMT expression.