Biochemical changes associated with fatty liver in geese

Studying biochemical changes in the blood and liver of geese during cramming showed significant increases in the liver enzymes: malic dehydrogenase (MDH), lactic dehydrogenase (LDH), aspartate aminotransferase (AST) and malic enzyme (ME), and a decrease in alkaline phosphatase (ALP). No significant changes were seen in the activity of isocitric dehydrogenase (ICDH), and glucose 6 phosphate dehydrogenase (G6PDH). There were significant increases in serum ME, ICDH, LDH, MDH, AST, acid phosphatase (ACP), sorbitol dehydrogenase (SDH), and total lipids and decreases in serum ALP, albumin and the haemocrit. No significant changes were seen in the activity of cholinesterase, glucose, total proteins, globulins and inorganic phosphorus. There were good correlations between liver size and the change of some of the biochemical parameters studied, which may serve as markers for the presence and degree of liver fattening. There were differences between families of gray and white geese and concentrations and activities of the blood constituents paralleled the degree of liver fattening. The possibility of using these parameters as genetic markers is discussed. No correlations were found between the liver and serum biochemical parameters. The effect of transporting the geese from the farm to the slaughter house on the levels of the blood constituents is described.     

Detection of crosslinks with the comet assay in relationship to genotoxicity and cytotoxicity

The alkaline comet assay is a sensitive test for the detection of a variety of DNA lesions. However, crosslinks are not readily detected under standard test conditions. Recently, modifications have been introduced measuring crosslinks by determining the reduction of induced DNA migration. We used the comet assay to comparatively investigate in V79 cells the effect of three different crosslinkers: formaldehyde (FA), which predominantly induces DNA-protein crosslinks, cisplatin (DDP), which mainly produces DNA-DNA-intrastrand crosslinks, and mitomycin C (MMC), which mainly leads to DNA-DNA-interstrand crosslinks. In the standard alkaline comet assay, only MMC induced a slight increase in DNA migration at high toxic concentrations. FA and DDP did not induce any DNA migration under the test conditions used. In the modified comet assay, all three crosslinkers led to a clear reduction of gamma-ray-induced DNA migration. This reduction was seen in the case of FA parallel to the induction of cytotoxicity and SCE, while for MMC and DDP induction of cytotoxicity, SCE and HPRT gene mutations occurred at much lower concentrations than the effects in the comet assay. The DNA-DNA crosslinkers caused a reduction of induced DNA migration only at cytotoxic concentrations. Our results indicate that the modified comet assay protocol is a sensitive test for the detection of DNA-protein crosslinks. However, the results for MMC and DDP suggest that the modified protocol is not well suited for the evaluation of DNA-DNA crosslinkers. Furthermore, the relationship between crosslinking and genotoxicity seems to be very different for the three different types of crosslinking substances.     

Biochemical changes associated with the fatty liver syndrome in cows

There were significant changes in enzyme activities and concentrations of metabolites in the blood and liver of cows with fatty livers when compared to normal cows. Blood and liver samples were taken from cows at the abattoir immediately after slaughter. The liver was checked for pathological signs and the samples were divided according to the degree of fatty changes. Three groups were studied: controls showing no gross pathological signs, mild fatty infiltration and severe infiltration. In cows with fatty liver, there were significant increases in the serum activities of isocitric dehydrogenase (ICDH), glucose-6-phosphate dehydrogenase (G6PDH), glutamic dehydrogenase (GLDH), lactic dehydrogenase (LDH), malic dehydrogenase (MDH), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and acid phosphatase (ACP). In the fatty liver, the activities of the enzymes, ICDH, G6PDH, LDH, MDH, ALP and malic enzyme (ME) were significantly higher, while sorbitol dehydrogenase (SDH) was significantly lower. While serum total lipid decreased, the opposite was seen in the liver with higher lipid content, mainly due to triglycerides and cholesterol esters. The significant increases in the NADPH generating enzymes ME, ICDH, G6PDH and MDH, which are required for fatty acid synthesis, suggest that the lipids accumulated in the liver are not only of extrahepatic origin, mobilized into the liver, but also arise from increased lipid synthesis in the liver which is induced during the laying down of fat in the liver. Measurement of the serum NADPH generating enzymes may serve as a useful biochemical test specific for fatty liver in cows.     

Diamine extension of glutaraldehyde crosslinks mitigates bioprosthetic aortic wall calcification in the sheep model

We previously have been able to show that fixation at increasing concentrations of glutaraldehyde (GA) leads to mitigated rather than facilitated tissue calcification. The purpose of the present study was to introduce additional crosslinks and provide evidence that crosslink density may be an underlying inhibitory principle. Entire aortic roots were chosen to verify the concept on the challenging aortic wall tissue. Porcine aortic roots were crosslinked with 0.2% GA, 3%GA, and 3% GA containing an interim step that introduced diamine bridges. Crosslink efficiency was determined on the basis of shrinkage temperature (SrT degrees ), resistance to protease digestion (RPD), residual amine analysis (RA), and tensile modulus (E(10)). Calcium levels, calcification patterns, and inflammation were assessed after 6 and 24 weeks of implantation in a sheep circulatory model. Crosslink efficiency in aortic wall tissue was moderately affected by increasing the fixative concentration from 0.2% GA to 3% GA (SrT degrees from 85.7 degrees +/- 0.3 degrees to 87.5 degrees +/- 0.3 degrees C, p < 0.002; RPD from 24.2 +/- 1.2 to 29.1 +/- 0.7%, p < 0.003; RA from 0.069 +/- 0.004 to 0.058 +/- 0.003 micromol/mg, p < 0.03, and E(10) from 1.9 +/- 0.11 to 2.94 +/- 0.34 MPa, p < 0.01), but it was distinctly enhanced when diamine bridges were introduced (SrT degrees from 87.5 degrees +/- 0.3 degrees to 93.4 degrees +/- 0.3 degrees C, p < 0.0001; RPD from 29.1 +/- 0.7 to 68.4 +/- 1.8%, p < 0.0001; and E(10) from 2.94 +/- 0.34 to 6.80 +/- 0.61 MPa, p < 0.0003). Aortic wall calcification was reduced significantly by increasing the GA concentration from 0.2 to 3% [37.8%, p = 0.076 (6 weeks) and 34.0%, p = 0.008 (24 weeks)] and further reduced by the introduction of additional diamine [84.0%, p = 0.006 (6 weeks) and 29.8%, p = 0.037 (24 weeks)]. The combined effect of increased GA concentration plus an interim diamine step on aortic wall tissue resulted in a 90% and 53.7% reduction of calcification after 6 weeks and 24 weeks, respectively. The correlation coefficients between calcification and SrT degrees, RDP, and E(10) was -0.9767, -0.9460, and -0.9740, respectively (6 weeks). The inflammatory host reaction regularly found in 0.2% fixed tissue was practically abolished through the introduction of diamine bridges. Our study demonstrated a distinct correlation between the mitigation of aortic wall calcification and three parameters used to assess crosslink density.     

Biochemical changes associated with alpha-difluoromethylornithine uptake and resistance in Trypanosoma brucei

Procyclic Trypanosoma brucei grown in semi-defined media are sensitive to alpha-difluoromethylornithine (DFMO) (EC50 100 microM), an inhibitor of ornithine decarboxylase (ODC), a key enzyme in polyamine biosynthesis. Organisms resistant to 5 mM DFMO (EC50 greater than 20 mM) were obtained by passage in incremental amounts of drug. Resistant and wild-type cells accumulated DFMO by passive diffusion with a consequent decrease in polyamine levels, indicating inhibition of ODC in both cell types. The resistant phenotype was stable in the absence of DFMO, in which state there was no increase in ODC abundance or activity. By kinetic analysis, the ODC of resistant cells appeared normal. In wild-type and resistant cells, [3H]DFMO equally and uniquely affinity-labelled a 50 kDa polypeptide corresponding to the ODC subunit. Levels of ODC and tubulin mRNAs were elevated 4-fold in resistant cells grown in the presence of DFMO, although there was no indication of gene amplification. The intracellular concentration of dihydrotrypanothione (N1,N8-bis(glutathionyl)-spermidine), a redox intermediate unique to kinetoplastids, was unchanged in resistant cells growing in DFMO but was halved in wild-type cells exposed to DFMO for 48 h. The exceptionally elevated levels of ornithine found in DFMO-treated resistant cells most likely play a crucial role in cell survival by maintaining intracellular concentrations of dihydrotrypanothione by competing with DFMO for ODC.     

Biochemical changes in the rat brain associated with dinitrophenol-induced brain edema.

The present paper was designed to the study of cerebral edema induced by intracarotid infusion of dinitrophenol. The determinations included variations in three lysosomal enzymes (acid phosphatase, cathepsin C and beta-glucuronidase), Na+-K+-ATP-ase, changes in cerebral RNA and protein concentrations and the synthesis of these macromolecules in vitro. In experimental brain edema a drastic drop in the activity of lysosomal enzymes took place. The acid phosphatase decreased to less than 30% of controls. Cathepsin C and beta-glucuronidase were reduced about 30% and 50% of control levels respectively. Protein concentration in the cerebral tissue also decreased by more than 50%. The concentration of RNA, RNA synthesis, and the level of Na+-K+-ATP-ase remained unchanged. Protein synthesis was stimulated by 75% (against controls). All these phenomena were suppressed when the animals subjected to the action of dinitrophenol were concomitantly treated with the antiacidotic substance, tris (hydroxymethyl) aminomethane.     

Biochemical changes in blood and tissues associated with round heart disease in turkey poults

Enzyme levels in the plasma, liver and heart muscle from normal healthy and round heart diseased (RHD) turkey poults are described. RHD was induced by feeding with furazolidone or developed spontaneously. Lactic dehydrogenase (LDH), isocitric dehydrogenase (ICDH) and creatine-phosphokinase (CPK) were significantly lower in the heart muscle of birds showing RHD symptoms, while liver cholinesterase (CE) was significantly higher in the diseased birds in comparison to the controls. LDH isoenzyme pattern in the heart muscle and liver showed a shift toward the M type tetramers. The significance of these findings is discussed.     

Evidence of crosslinks in a butadiene-divinylbenzene-ethylvinylbenzene copolymer by metathesis degradation

1,3-Butadiene was copolymerized with a mixture of divinylbenzene isomers containing ethyl-vinylbenzene isomers. The crosslinked copolymers were degraded in a cross metathesis reaction with (Z)-2-butene or (E)-3-hexene using the catalyst WCl₆/Sn(CH₃)₄. The low-molecular-weight products were investigated by gas chromatography/mass spectrometry coupling. Products containing the crosslinks were found. Others were attributable to copolymer units resulting from butadiene and ethylvinylbenzene. Characteristic mass spectra of the products are discussed.     

CD59 is physically and functionally associated with natural cytotoxicity receptors and activates human NK cell-mediated cytotoxicity

Triggering of cytotoxicity in human NK cells is induced by the combined engagement of several triggering receptors. These include primary receptors such as NKG2D and the natural cytotoxicity receptors (NCR) NKp30, NKp46 and NKp44, while other molecules, including 2B4, NTB-A and NKp80, function as co-receptors. As reported in the present study, during an attempt to identify novel NK receptors or co-receptors, we found that CD59 functions as a co-receptor in human NK cell activation; engagement of CD59 by specific mAb delivers triggering signals to human NK cells, resulting in enhancement of cytotoxicity. Similar to other NK co-receptors, the triggering function of CD59, a glycosylphosphatidylinositol (GPI)-linked protein, depends on the simultaneous engagement of primary receptors such as NCR. Accordingly, CD59-dependent triggering was virtually restricted to NK cells expressing high surface densities of NKp46, and mAb-mediated modulation of NKp46 resulted in markedly decreased responses to anti-CD59 mAb. Biochemical analysis revealed that CD59 is physically associated with NKp46 and NKp30. Moreover, engagement of CD59 resulted in tyrosine phosphorylation of CD3zeta chains associated with these NCR, but not those associated with CD16. Thus, CD59-mediated costimulation of NK cells requires direct physical interaction of this GPI-linked protein with primary triggering NK receptors.     

Epstein-Barr virus nuclear antigen 1 (EBNA1) induced cytotoxicity in epithelial cells is associated with EBNA1 degradation and processing

Epstein-Barr virus nuclear antigen 1 (EBNA1) has a central role in the maintenance and segregation of the Epstein-Barr virus (EBV) episome and by virtue of a glycine-alanine repeat domain is prevented from being endogenously processed for recognition by HLA class I restricted cytotoxic T lymphocytes (CTLs). We found that EBNA1 expression resulted in growth inhibition and a G2/M arrest in human squamous epithelial cell lines (SCC12F, SVK) but not epithelial cell lines of glandular origin (Hela, Ad/AH). The cytotoxicity of EBNA1 was associated with EBNA1 degradation and both these effects were blocked in SCC12F cells expressing either the anti-apoptotic bcl-2 protein or the EBV homolog of bcl-2, BHRF1. The endogenous degradation of EBNA1 in SVK epithelial cells was associated with specific CTL recognition, an effect not evident in EBNA1-expressing Hela cells. Consistent with the inability of SVK cells to tolerate EBNA1 expression, studies with a recombinant EBV demonstrated that SVK cells are unable to maintain stable virus infection, whereas Hela cells are able to efficiently establish latent EBV infection. These data have important implications for both the cellular requirements necessary to sustain a stable EBV infection and for the possible role of CTL responses in controlling EBV infection of epithelial cells.     

Biochemical classification of Klebsiella correlated with the severity of the associated disease

The biochemical classification of the Klebsiella proposed by Cowan, Steel, Shaw, and Duguid (1960) has been applied to 50 strains isolated as the pure or predominant growth from sputum, and Klebsiella species have been correlated with the severity of the chest infection in the patient. A modification in nomenclature is suggested.     

Biochemical and functional changes after immunization of rats with angiotensin II

Bulletin of Experimental Biology and Medicine -     

Endometrial changes associated with myomata of the uterus

The endometrium of 30 uteruses with myomata was studied at four standard sites. Glandular atrophy over a myoma or opposite a myoma was the most constant finding. At the margin of a myoma hyperplastic glands were frequently found, and distorted, elongated, or dilated glands were present at this site in half of all specimens. Other changes included adenomyosis and the separation of glands by muscle fibres from the basal layer of the endometrium. The coexistence of many of these findings in endometrial curettings can lead to the histological diagnosis of uterine myomata. Two factors, mechanical and hormonal, may be responsible and their mechanisms are discussed.     

基于改性壳聚糖纳米胶束的制备和表征及其细胞毒性评价

背景：壳聚糖进行化学改性以制备性能优良且细胞毒性低、生物相容性高、可降解的聚合物纳米胶束,在药物控释、组织工程等领域获得普遍应用。 目的：将强疏水链十八烷氧基接枝到N-琥珀酰壳聚糖分子中,制备结构稳定、粒径较小的聚合物胶束,以获得可适用于药物传递载体或医学生物材料领域的聚合物纳米胶束。 方法：用N-琥珀酰壳聚糖和十八烷基缩水甘油醚反应,在壳聚糖衍生物中引入长链疏水基。 结果与讨论：成功制备出聚合物纳米胶束,通过红外光谱和1H核磁波谱表征,证实壳聚糖分子中成功引入了琥珀酰基和十八烷氧基。通过动态激光散射测量出其粒径在136~166 nm,其临界胶束溶度在1.67×10^-3~3.35×10^-3 g/L,反映出胶束具有非常好的稳定性,而且其临界胶束浓度值和粒径随着疏水链接枝率的增加而减少。MTT法检测说明该胶束对细胞毒性极低。