Establishment of RP-HPLC detection method of N-isopropyl oxamate in the serum of plateau pikas / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To explore the intergrating of N-isopropyl oxamate and serum protein and establish a high performance liquid chromatography (HPLC) detection method of N-isopropyl oxamate (specific inhibitor of testis-specific lactate dehydrogenase (LDH-C4)) in the blood of plateau pikas.</p><p><b>METHODS</b>Twenty highland pika 150-200 g, were randomly divided into two groups (n = 10): control group and inhibitor group. Different concentrations of N-isopropyl oxamate were added to examine the intergrating of N-isopropyl oxamate and serum protein. In order to determine its concentration in the pika blood accurately, we used the method of adding trypsin to incubate the serum first, followed by trichloroacetic acid treatment and detecting by HPLC. Results: When the concentrations of N-isopropyl oxamate in the pika serum were added to 0.05 mmol/L, 0.1 mmol/L, 1 mmol/L, 10 mmol/L, 16.7 mmol/L, 33.3 mmol/L and 100 mmol/L, the intergrating rates between N-isopropyl oxamate and plateau pika serum were 100%, 100%, 100%, 86.84%, 54.11%, 40.10% and 20.18%, respectively. The method established in this paper was good on recovery rates, precision and stability. A good linearity was obtained in the range of 0.0125-0.25 mmol/L. When the concentrations of N-isopropyl oxamate in the serum were added to 0. 15 mmol/L,0.3 mmol/L and 1 mmol/L, the recovery rates were 98.05%, 98.98% and 98.12%, respectively; the precision relative standard deviation( RSD) of concentrations were 1.17%, 0.92% and 0.83%, respectively; the stability relative standard deviation (RSD) of concentrations were 1.38%, 1.40% and 0.88%, respectively. The repeatability RSD of the method was 1.76%. Quantitative limit was 0.0125 mmol/L.</p><p><b>CONCLUSION</b>N-isopropyl oxamate has a strong affinity with plateau pika serum protein that can't be accurately determined with common HIPLC method. It can be accurately determined in the blood by adding trypsinto digest the serum protein first, followed by adding trichloroacetic acid to precipitate the protein.</p>

The expression of the sperm-specific lactate dehydrogenase gene Ldh-c in plateau pika (Ochotona curzoniae) cardiac muscle and its effect on the anaerobic glycolysis / 生理学报

The plateau pika (Ochotona curzoniae) has a strong adaptability to hypoxic plateau environment. We found that the sperm-specific lactate dehydrogenase (LDH-C4) gene Ldh-c expressed in plateau pika cardiac muscle. In order to shed light on the effect of LDH-C4 on the anaerobic glycolysis in plateau pika cardiac muscle, 20 pikas were randomly divided into the inhibitor group and the control group, and the sample size of each group was 10. The pikas of inhibitor group were injected with 1 mL 1 mol/L N-isopropyl oxamate, a specific LDH-C4 inhibitor, in biceps femoris muscle of hind legs, each leg with 500 μL. The pikas of control group were injected with the same volume of normal saline (0.9% NaCl). The mRNA and protein expression levels of Ldh-c gene in plateau pika cardiac muscle were determined by real-time PCR and Western blot. The activities of LDH, and the contents of lactate (LD) and ATP in cardiac muscle were compared between the inhibitor group and the control group. The results showed that 1) the expression levels of Ldh-c mRNA and protein were 0.47 ± 0.06 and 0.68 ± 0.08, respectively; 2) 30 min after injection of 1 mL 1 mol/L N-isopropyl oxamate in biceps femoris muscle, the concentration of N-isopropyl oxamate in blood was 0.08 mmol/L; 3) in cardiac muscle of the inhibitor group and the control group, the LDH activities were (6.18 ± 0.48) U/mg and (9.08 ± 0.58) U/mg, the contents of LD were (0.21 ± 0.03) mmol/g and (0.26 ± 0.04) mmol/g, and the contents of ATP were (4.40 ± 0.69) nmol/mg and (6.18 ± 0.73) nmol/mg (P < 0.01); 5) the inhibition rates of N-isopropyl oxamate to LDH, LD and ATP were 31.98%, 20.90% and 28.70%, respectively. The results suggest that Ldh-c expresses in cardiac muscle of plateau pika, and the pika cardiac muscle may get at least 28% ATP for its activities by LDH-C4 catalyzed anaerobic glycolysis, which reduces the dependence on oxygen and enhances the adaptation to the hypoxic environments.

Synthesis, characterization and catalytic activity of copper [II], nickel [II] and cobalt [II] complexes derived from novel hydrazone drivatives of oxamic hydrazide

A series of new coordination complexes of Cu[II], Ni[II] and Co[II] with omaxic hydrazide [L[1]], N,N' - [salicylidene]- oxamic hydrazide [L[2]] and N,N' - bis [naphthalidene] - oxamic hydrazide [L[3]] have been synthesized and characterized by elemental analysis, magnetic moment, IR, UV - Vis spectra nd molar conductance. The thermal behavior of the complexes was investigated by TG A and DTA techniques. The catalytic activity of the complexes to decolorize the Allura-Red [food dye] in presence of H[2]O[2] was studied

[Study the effect of oxamate on rat sperm motility in vivo]

LDH- C4 is an isoenzyme of lactate dehydrogenase that is found in mature testes and spermatozoa of species with internal fertilization. Its physiological function appears related to metabolic processes that provide energy for motility and survival of spermatozoa. Oxamate is a new selective competitive inhibitor of sperm LDH- C4 with pyruvate as substrate. In the present experimental study on male rat, the effectiveness of oxamate was evaluated as a novel approach to the development of a male contraceptive. In this study, 20 adult rats were divided into 4 groups, the first used as control and the remaining three used as experimental groups. Experimental groups received different concentration, of oxamate [150, 300, 600 mg/kg/,ip] for 45 days. Control animals received normal saline solution. The sperms from the cauda division of epididymidis were collected by placing minced cauda in culture medium [T6] for one hour at 37°C in a 5% CO[2] atmosphere. Sperm motility was evaluated utilizing Makler chamber and compared with the control group. Statistical analysis was performed by the student t- test and one - way ANOVA. Progressive sperm motility in control and treated their groups were%60.3 +/- 2.8],%50 +/- 2.4],%41.5 +/- 1.9],%19 +/- 2.2] respectively. We conclude that oxamate in vivo can reduce sperm motility significantly and this reduction was concentration-dependent. The results of this work show that sperm motility can be reduced by concentration- dependent effect of oxamate under in vivo conditions

Studies of the effects of molecular weight on the gamma irradiation degradation of poly [Methylmetacrylate] doped with p-N, N-dioxaloylaminobenze -N',N'-dioxaloylsulphonyloxamide and its cobalt [II] complex

Protection of some poly [methylmethacrylate] samples against gamma rays had been investigated in the absence and presence of p N,N-dioxaloylamjnobenzene-N', N' dioxaloylbenzenesul-phony-loxamide and its cobalt [II] complex. The pure PMMA [without additives], PMMA-ligand and PMMA-cobalt [II] complex composite samples were irradiated with gamma rays for different exposure doses [5, 15, 25, 35, 50, 75 and 100 kGy]. Viscosity average molecular weight [Mv-values] and thin layer chromatographic measurements were carded out after each irradiation dose. The maximum protection against gamma ray was found when 1% of the organic ligand or its cobalt [II] complex is used in the polymer matrix

Blood acidification in the swimbladder: mechanisms and metabolic pathways

The metabolism of gas gland cells of the swimbladder epithelium is specialized for the production of acidic metabolites that are released into the blood stream and provoke an increase in gas partial pressure by reducing the effective gas-carrying capacity of the blood. In a subsequent step this initial increase in gas partial pressure is multiplied by back-diffusion of gas molecules from the venous to the arterial side in the countercurrent system, the rete mirabile. Thus, gas partial pressures of up to several hundred atmospheres can be generated in the swimbladder. Measurements of metabolic end products and analysis of the formation of 14C02 from [1-14(superscription) C] glucose and [6-14(superscription) C] glucose revealed that the acidic metabolises are lactic acid, produced in the glycolytic pathway, and also C02, formed in the pentose phosphate shunt. C02 easily enters the blood stream by diffusion. The release of protons from isolated gas gland cells, however, is highly dependent on the extracellular sodium concentration. This sodium dependence can in part be blocked by addition of amiloride, indicating that a Na+/ H+ exchanger is involved in the release of protons. A significant decrease in the rate of proton secretion in the presence of the carbonic anhydrase inhibitor ethoxzolamide indicates that the second major route for the release of protons includes carbonic anhydrase activity and the diffusion of C02.

Determinación cuantitativa del ácido oxático por el método permanganométrico en: citrullus vulgaris, sandia / Oxatic acid cuantitative determination by permangonometric method in citrullus vulgaris sandia

El ácido oxálico es un ácido que puede encontrarse en productos vegetales que son consumidos por la población, y que por sus efectos negativos en la absorción del calcio y otros nutrientes pueden dar lugar a un proceso acumulativo de oxalato de calcio que degeneraria en uan urolitiasis y calculosis renal. Se hizo la determinación cualitativa y cuantitativa del ácido oxálico en la sandia (Citrullus vulgaris) tanto en pulpa como en corteza utilizando el método I de la ADAC o método permanganometrico. Según la técnica se procede a una hidrólisis conHel Gn en caliente y una subsiguiente precipitación con el reactivo fosfotungstico para extraer el ácido oxatico, y precipitarlo como oxalato de calcio que es luego disuelto con ácido sulfúrico al 10 por ciento para cuantificarlo en caliente con KMnO4 al o.01n. Los resultados encontrados para la pulpa de sandia fue de 25,40 mg/100g de muestra y de 31,7 mg/100g de muestra en corteza. Estas cantidades halladas no son muy elevadas, pero pueden llegar a causar un incremento de la formación de oxalato de calcio a nivel renal.

Estudio de algunos factores que influyen en la concentración de ácido orálico en equisetum bogotense KBH "cola de caballo" zea mays L. "maiz". Solanum tuberosum L. "papa" y su cuantificación por lo métodos de titulación permanganometrica y de absorción atómica / Some factors study of Oralic acid in equisetum bogotense KBH \"cola de caballo\", zea mays L. \"maiz\" Solanum tuberosum L. \"papa\" y su cuantification by the methods of permanganometric titulation by atomic absortion

Se usaron 3 plantas diuréticas. Determinar ácido oxálico en las diferentes drogas tanto crudas como cocidas en forma individual y combinado, usando los métodos de la ADAC. La edad de la planta, es determinante en el contenido de ácido oxálico. Las muestras crudas lanzaron mayor porcentaje de ácido oxálico. Se comprobó que existen algunos factores determinantes que influyen directa o indirectamente en la concentración de ácido oxálico en los vegetales.