黄芪总甙延缓衰老的作用及其机制

目的:研究黄芪总甙(astragalosides,AST)延缓衰老的作用及其机制。方法:采用小鼠D-半乳糖(D-galactose,D-gal)人工衰老模型和自然衰老模型(17月龄),以小鼠协调运动、学习记忆、以及免疫功能作为指标,同步观察药物的作用。结果:AST(40mg·kg~(-1)·d~(-1),ig,10周)可明显恢复D-gal衰老小鼠的协调运动和学习记忆功能,使其过低的ConA诱导脾淋巴细胞增殖反应及IL-2产生明显升高,但对LPS诱导B淋巴细胞增殖反应无明显影响。AST(40mg·kg~(-1)·d~(-1),ig,3个月)对17月龄小鼠亦有类似作用。结论:AST对D-gal衰老小鼠和由中年期(14月龄)进入老前期(17月龄)小鼠的自然衰老进程均有明显的延缓作用,可能与其免疫调节作用有关。     

A method for determining nonelectrolyte uptake by adult Schistosoma mansoni using compartmental analysis of hexose fluxes

A steady-state compartmental analysis of galactose, glucose and 3-O-methylglucose fluxes was conducted on male and female Schistosoma mansoni. The method has several advantages over previously used initial rate studies. A nonlinear log-linear plot of glucose exchange is discussed in terms of differentiating between metabolized and nonmetabolized substrates in transport studies. K_t values and marker distribution volumes are estimated from the compartmental analysis and it is concluded that 3-O-methylglucose is not suited as a substrate for hexose transport studies in S. mansoni.     

Influenza A virus enhances basophil histamine release and the enhancement is abolished by carbohydrates

Basophil histamine release was studied in leukocyte suspensions from normal individuals and from patients allergic to house dust mite or birch pollen. Mediator release caused by IgE-mediated reactions was examined by stimulating the cells with anti-IgE or specific antigens, and the calcium ionophore A23187 was used for a non-immunological histamine release. In all experiments influenza A virus caused a synergic enhancement of the mediator release and the potentiation was abolished by galactose (10(-7) to 10(-6) M) and by 10(-6) to 10(-5) M of N-acetylglucosamine, alpha-methyl-D-glucoside, alpha-methyl-D-mannoside, N-acetylneuraminic acid and lactose, but not by glucose. Wash-out experiments show that the sugars prevent the aggravation of mediator release by a binding of sugar to the basophil cell membrane, thereby causing a blockade of binding sites responsible for the potentiating effect of virus.     

The target antigens of naturally occurring human anti-beta-galactose IgG are cryptic on porcine aortic endothelial cells

Abstract: The identification of the xeno‐antigens/xeno‐antibodies combinations involved in pig‐to‐human xenograft rejection is an essential step for understanding this process and for the development of procedures to prevent it. Although it is widely accepted that the terminal disaccharide Galα1,3Gal‐R is by far the major epitope recognized by human natural antibodies reactive with pig tissues, there is also evidence that other carbohydrates epitopes might be important in xenograft rejection.
In an attempt to further improve our knowledge of the repertoire of human natural antibodies with anti‐pig specificity we sought to determine whether naturally occurring human anti‐β‐galactose IgG could interact with porcine aortic endothelial cells (PAEC). Histochemical analysis of porcine aorta sections revealed that the carbohydrate structures recognized by the anti‐β‐galalactose IgG are present on endothelial cells but in a cryptic form that can be unmasked by sialidase treatment. These structures were also found to be cryptic in cultured PAEC. In addition we demonstrated that PAEC may adsorb fetal calf serum (FCS) glycoproteins when cultured in FCS‐supplemented medium, a process susceptible to generating artifactual observations in carbohydrate antigens analysis.
In conclusion, despite their abundance, human anti‐β‐galactose IgG do not represent a primary concern in pig‐to‐human xenotransplantation as the carbohydrate structures to which they bind are normally masked by sialic acid residues on porcine endothelial cells. However, whether these cryptic epitopes might be exposed on endothelial cells from genetically engineered animals should be further investigated because, if so, additional approaches will be needed to suppress their interaction with human anti‐β‐galactose IgG.     

An acidic glycoconjugate from Lythrum salicaria L. with controversial effects on haemostasis

Aim of the study

Lythrum salicaria L. belongs to the small Lythraceae family of 22 genera, which range in habit from herbs to shrubs and trees found with worldwide distribution (Heywood, 1993). The generic name of Lythrum derived from Greek “luthron”—blood, possibly referring to the color of the flowers or to the one of its herbal use as an astringent to stop bleeding ( [26], [17] and [18]). The flowering parts and the flowering branch tips are used in traditional medicine and pharmaceuticals internally in a form of decoctions or as extracts for treatment of diarrhea, chronic intestinal catarrhs, hemorrhoids and eczema, or externally to treat varicose veins, venous insufficiency and gums ( [Mantle et al., 2000] and [Rauha et al., 2000]). The aim of this study was to isolate the plant glycoconjugate from flowering parts of Lythrum salicaria, and to verify its influence on blood coagulation process.

Materials and methods

From the air-dried flowering parts of this plant a water-soluble glycoconjugate has been isolated by hot alkaline extraction followed by neutralization and purification by multi-steps extraction with organic solvents, dialysis and concentration. The plant isolate was tested in vitro on anticoagulant activity on human plasma, and on Wistar rats blood system in vivo as well as ex vivo.

Results

A dark brown isolate was obtained in the yield of 8% of starting material (w/w) as a macromolecular compound with M_w ∼ 12,500. Chemical analysis revealed the presence of carbohydrates (30%), phenolics (1 g contained 1.2 mM of gallic acid equivalent) and proteins (0.8%). The result of compositional analyses of carbohydrate part revealed the predominance of uronic acids (∼66%), galactose (∼12%), rhamnose (∼10%) and arabinose (∼9%) residues indicating thus the presence of pectic type of polymers, i.e. galacturonan and/or rhamnogalacturonan associated with arabinogalactan in Lythrum glycoconjugate. In vitro and ex vivo experiments showed complete inhibition of plasma clot formation, however, the application of Lythrum glycoconjugate in vivo showed controversial effect on animal blood system in comparison with in vitro ones, i.e. pro-coagulant activity.

Conclusion

The in vivo results give a scientific explanation for the traditional use of Lythrum salicaria as a styptic agent. It seems that pro-coagulant activity of this complex could be probably connected with the other factors in blood circulation system, like platelets.     

Bacteria and endotoxin enhance basophil histamine release and potentiation is abolished by carbohydrates

Histamine release caused by anti-IgE, specific antigens and calcium ionophore A23187 was examined in leukocyte suspensions from healthy individuals and patients allergic to house dust mite and birch pollen. Staphylococcus aureus and LPS from Salmonella typhimurium were found to cause a synergistic enhancement of the release. The potentiation of mediator release by the bacteria and the endotoxin depends on a binding to the basophilocyte, followed by a non-transient event, since the potentiating effect persists after preincubation of the cells with the LPS followed by washout and leaving the cells for 30 min at 37 degrees C before stimulation with anti-IgE. The potentiation was abolished or reduced by galactose (10(-7) and 10(-6) M) and N-acetylglucosamine (10(-6) and 10(-5) M), acting by a binding to the basophil cell membrane, demonstrated by the persistence of effect after preincubation and washout of unbound sugar.     

失血及成分输血对ICG和半乳糖负荷试验的影响

目的：靛氰绿（ＩＣＧ），半乳糖负荷试验结果除与肝细胞功能有关外，还受肝循环血量、肾功能等因素的影响。本研究拟观察全身及肝循环紊乱状态下，上述二试验结果的变化。方法：以失血（循环血量的１５％，３０％，４０％，ｎ＝７）和成分输血（全血、血浆、血球，ｎ＝６）家兔为对象，施行ＩＣＧ（１．５ｍｇ／ｋｇ）和半乳糖（３５０ｍｇ／ｋｇ）负荷试验。观察指标为血中ＩＣＧ１５ｍｉｎ潴留率（ＩＣＧＲ１５），ＩＣＧ清除率（     

Apparent Galactose Appearance Rate in Human Galactosemia Based on Plasma [C]Galactose Isotopic Enrichment

Determination of endogenous galactose formation in galactosemic subjects provides important information in understanding the etiology of the long-term complications. To accomplish this task a sensitive method for measurement of isotopic enrichment of plasma galactose was developed. The aldononitrile pentaacetate derivative of galactose was utilized for gas chromatography/mass spectrometry analysis. Using a phenyl-methylsilicone capillary column, adequate separation of galactose from glucose was obtained by temperature programming of the chromatography. The specific fragmentation pattern of m/z 212, 225, 314 from -[¹²C]galactose and m/z 213, 226, 315 from -[¹³C]galactose was used for the galactose enrichment measurement by atom percent excess (APE). There was good correlation between expected enrichment and determined APEs at galactose concentrations of 1, 2, and 5 μmol/L with a coefficient of variation ranging from 0.22 to 7.17%. The method provides an accurate estimation of plasma [¹³C]galactose enrichment from which the galactose production rate can be calculated. The steady-state plasma -[¹³C]galactose isotopic enrichment of three individuals with galactosemia, two males ages 33 and 13, and one female age 9, during constant infusion of -[¹³C]galactose was 55, 41, and 55%, allowing the estimation of the apparent galactose appearance rate of 0.62, 1.09, and 0.82 mg/kg/h, respectively. The reanalysis of three previous studies by the present method found that APE values determined by the method then employed, butylboronate acetate derivatization, were systemically lower than those determined with aldononitrile pentaacetate derivatization, making for an overestimation of the apparent galactose appearance rate. The small plasma sample volumes needed make it feasible to perform these studies in infants and young children with galactosemia.     

儿童乳糖吸收不良的临床与实验研究

本文参考Arola描述的方法对41名健康儿童进行乙醇乳糖耐量试验(LTTE)血、尿半乳糖测定。血半乳糖(B-gal)<0.3mmol/L、尿半乳糖(U-gal)<2mmol/L诊断为乳糖吸收不良(LM)。另采用LTTE尿法和症状反应记分(SRS)法对138名健康儿童和95名急性腹泻小儿做了LM和乳糖不耐症(LI)的研究。结果提示LTTE半乳糖测定法诊断LM可信;健康儿童随年龄增加LM和LI发生率亦增加;轮状病毒肠炎易并发LM和LI。     

The Quantitative Liver Function as Measured by the Galactose Elimination Capacity

ABSTRACT. Quantitative liver function was estimated by determination of the galactose elimination capacity (GEC) in 29 patients with steatosis, 50 with cirrhosis and 42 control patients without clinical history or signs of liver disease. In patients with steatosis and cirrhosis, clinical signs of liver disease were recorded and the most common liver tests were carried out. The degree of histological changes was investigated in needle liver biopsies performed in a close relation to the GEC determinations. A positive correlation between GEC and body weight and body surface area was observed in all three patient groups. GEC (absolute value, per kg body weight and per m² body surface area) was significantly different (p<0.001) between the three groups, but was without diagnostic value due to a broad scattering of results in each group. This may be due to methodological errors in the determination of GEC, but also to the large biological variation in normal man and the pathophysiological conditions in patients with liver disease. Neither in patients with steatosis nor in patients with cirrhosis could significant relations be found between GEC and clinical signs of liver disease or the degree of severity of histological changes assessed semiquantitatively. In patients with cirrhosis but not in patients with steatosis, GEC was significantly correlated with the majority of the most commonly utilized liver tests.