Angiotensin-converting enzyme 2 improves liver fibrosis in mice by regulating autophagy of hepatic stellate cells

BACKGROUND Liver fibrosis is the common pathological process associated with the occurrence and development of various chronic liver diseases.At present,there is still a lack of effective prevention and treatment methods in clinical practice.Hepatic stellate cell(HSC)plays a key role in liver fibrogenesis.In recent years,the study of liver fibrosis targeting HSC autophagy has become a hot spot in this research field.Angiotensin-converting enzyme 2(ACE2)is a key negative regulator of reninangiotensin system,and its specific molecular mechanism on autophagy and liver fibrosis needs to be further explored.AIM To investigate the effect of ACE2 on hepatic fibrosis in mice by regulating HSC autophagy through the Adenosine monophosphate activates protein kinases(AMPK)/mammalian target of rapamycin(mTOR)pathway.METHODS Overexpression of ACE2 in a mouse liver fibrosis model was induced by injection of liver-specific recombinant adeno-associated virus ACE2 vector(rAAV2/8-ACE2).The degree of liver fibrosis was assessed by histopathological staining and the biomarkers in mouse serum were measured by Luminex multifactor analysis.The number of apoptotic HSCs was assessed by terminal deoxynucleoitidyl transferase-mediated dUTP nick-end labeling(TUNEL)and immunofluorescence staining.Transmission electron microscopy was used to identify the changes in the number of HSC autophagosomes.The effect of ACE2 overexpression on Wu Y et al.ACE2 improves liver fibrosis through autophagy WJG https://www.wjgnet.com 4976 September 7,2023 Volume 29 Issue 33 autophagy-related proteins was evaluated by multicolor immunofluorescence staining.The expression of autophagy-related indicators and AMPK pathway-related proteins was measured by western blotting.RESULTS A mouse model of liver fibrosis was successfully established after 8 wk of intraperitoneal injection of carbon tetrachloride(CCl4).rAAV2/8-ACE2 administration reduced collagen deposition and alleviated the degree of liver fibrosis in mice.The serum levels of platelet-derived growth factor,angiopoietin-2,vascular endothelial growth factor and angiotensin II were decreased,while the levels of interleukin(IL)-10 and angiotensin-(1-7)were increased in the rAAV2/8-ACE2 group.In addition,the expression of alpha-smooth muscle actin,fibronectin,and CD31 was down-regulated in the rAAV2/8-ACE2 group.TUNEL and immunofluorescence staining showed that rAAV2/8-ACE2 injection increased HSC apoptosis.Moreover,rAAV2/8-ACE2 injection notably decreased the number of autophagosomes and the expression of autophagy-related proteins(LC3I,LC3II,Beclin-1),and affected the expression of AMPK pathway-related proteins(AMPK,p-AMPK,p-mTOR).CONCLUSION ACE2 overexpression can inhibit HSC activation and promote cell apoptosis by regulating HSC autophagy through the AMPK/mTOR pathway,thereby alleviating liver fibrosis and hepatic sinusoidal remodeling.

Salvianolic acid B modulates the expression of drug-metabolizing enzymes in HepG2 cells

BACKGROUND: Enzymes involved in drug and xenobiotic metabolism have been considered to exist in two groups: phase I and phase II enzymes. Cytochrome P450 isoenzymes (CYPs) are the most important phase I enzymes in the metabolism of xenobiotics. The products of phase I metabolism are then acted upon by phase II enzymes, including glutathione S-transferases (GSTs). Herbs that inhibit CYPs such as CYP3A4 or that induce GSTs may have the potential to protect against chemical carcinogenesis since the mutagenic effects of carcinogens are often mediated through an excess of CYP-generated reactive intermediates. This study was designed to investigate the effects of salvianolic acid B (Sal B), a pure compound extracted from Radix Salviae Miltiorrhizae, a Chinese herb, on cell proliferation and CYP1A2 and CYP3A4 mRNA expression in the presence or absence of rifampicin, a potent inducer of CYPs and GST protein expression in HepG2 cells. METHODS: HepG2 cells were incubated with different concentrations of Sal B. Cell proliferation was determined by SYTOX-Green nucleic acid staining. CYP3A4 and CYP1A2 mRNA expression was assayed by real-time PCR. GST protein expression was analyzed by Western blotting. RESULTS: Low concentrations of Sal B (0-20 μmol/L) had no significant effects on cell proliferation, while higher concentrations (100-250 μmol/L) significantly inhibited proliferation in a concentration-dependent manner. Ten μmol/L Sal B, but not 1 μmol/L, down-regulated CYP3A4 and CYP1A2 mRNA expression after 24 hours of incubation, whereas both 1 and 10 μmol/L Sal B down-regulated CYP3A4mRNA expression after 96 hours of incubation; moreover, 1 and 10 μmol/L Sal B inhibited CYP3A4 mRNA expression induced by rifampicin. Both 1 μmol/L and 10 μmol/L Sal B increased GST expression. CONCLUSION: Sal B inhibits CYP3A4 and CYP1A2 mRNA expression and induces GST expression in HepG2 cells.

Angiotensin-converting enzyme 2 alleviates liver fibrosis through the renin-angiotensin system

The present letter to the editor is related to the study titled‘Angiotensin-converting enzyme 2 improves liver fibrosis in mice by regulating autophagy of hepatic stellate cells’.Angiotensin-converting enzyme 2 can alleviate liver fibrosis by regulating autophagy of hepatic stellate cells and affecting the renin-angiotensin system.

SIRT1 inhibits apoptosis of human lens epithelial cells through suppressing endoplasmic reticulum stress in vitro and in vivo

AIM:To explore the effect of silent information regulator factor 2-related enzyme 1(SIRT1)on modulating apoptosis of human lens epithelial cells(HLECs)and alleviating lens opacification of rats through suppressing endoplasmic reticulum(ER)stress.METHODS:HLECs(SRA01/04)were treated with varying concentrations of tunicamycin(TM)for 24h,and the expression of SIRT1 and C/EBP homologous protein(CHOP)was assessed using real-time quantitative polymerase chain reaction(RT-PCR),Western blotting,and immunofluorescence.Cell morphology and proliferation was evaluated using an inverted microscope and cell counting kit-8(CCK-8)assay,respectively.In the SRA01/04 cell apoptosis model,which underwent siRNA transfection for SIRT1 knockdown and SRT1720 treatment for its activation,the expression levels of SIRT1,CHOP,glucose regulated protein 78(GRP78),and activating transcription factor 4(ATF4)were examined.The potential reversal of SIRT1 knockdown effects by 4-phenyl butyric acid(4-PBA;an ER stress inhibitor)was investigated.In vivo,age-related cataract(ARC)rat models were induced by sodium selenite injection,and the protective role of SIRT1,activated by SRT1720 intraperitoneal injections,was evaluated through morphology observation,hematoxylin and eosin(H&E)staining,Western blotting,and RT-PCR.RESULTS:SIRT1 expression was downregulated in TMinduced SRA01/04 cells.Besides,in SRA01/04 cells,both cell apoptosis and CHOP expression increased with the rising doses of TM.ER stress was stimulated by TM,as evidenced by the increased GRP78 and ATF4 in the SRA01/04 cell apoptosis model.Inhibition of SIRT1 by siRNA knockdown increased ER stress activation,whereas SRT1720 treatment had opposite results.4-PBA partly reverse the adverse effect of SIRT1 knockdown on apoptosis.In vivo,SRT1720 attenuated the lens opacification and weakened the ER stress activation in ARC rat models.CONCLUSION:SIRT1 plays a protective role against TM-induced apoptosis in HLECs and slows the progression of cataract in rats by inhibiting ER stress.These findings suggest a novel strategy for cataract treatment focused on targeting ER stress,highlighting the therapeutic potential of SIRT1 modulation in ARC development.

Blood cell counts and nonalcoholic fatty liver disease: Evidence from Mendelian randomization analysis

BACKGROUND Previous research has highlighted correlations between blood cell counts and chronic liver disease.Nonetheless,the causal relationships remain unknown.AIM To evaluate the causal effect of blood cell traits on liver enzymes and nonalcoholic fatty liver disease(NAFLD)risk.METHODS Independent genetic variants strongly associated with blood cell traits were extracted from a genome-wide association study(GWAS)conducted by the Blood Cell Consortium.Summary-level data for liver enzymes were obtained from the United Kingdom Biobank.NAFLD data were obtained from a GWAS meta-analysis(8434 cases and 770180 controls,discovery dataset)and the Fingen GWAS(2275 cases and 372727 controls,replication dataset).This analysis was conducted using the inverse-variance weighted method,followed by various sensitivity analyses.RESULTS One SD increase in the genetically predicted haemoglobin concentration(HGB)was associated with aβof 0.0078(95%CI:0.0059-0.0096),0.0108(95%CI:0.0080-0.0136),0.0361(95%CI:0.0156-0.0567),and 0.0083(95%CI:00046-0.0121)for alkaline phosphatase(ALP),alanine aminotransferase(ALT),aspartate aminotransferase,and gammaglutamyl transferase,respectively.Genetically predicted haematocrit was associated with ALP(β=0.0078,95%CI:0.0052-0.0104)and ALT(β=0.0057,95%CI:0.0039-0.0075).Genetically determined HGB and the reticulocyte fraction of red blood cells increased the risk of NAFLD[odds ratio(OR)=1.199,95%CI:1.087-1.322]and(OR=1.157,95%CI:1.071-1.250).The results of the sensitivity analyses remained significant.CONCLUSION Novel causal blood cell traits related to liver enzymes and NAFLD development were revealed through Mendelian randomization analysis,which may facilitate the diagnosis and prevention of NAFLD.

Pathogenicity of Cell Wall Degrading Enzymes Produced by Botryodiplodia theobromae Pat. against Mangoes

[ Objective ] This study aimed to confirm the roles of cell wall degrading enzymes （CWDEs） produced by Botryodiplodia theobromae Pat. in the infec- tion of mango fruits. [ Method] Change of activities of five types of CWDEs produced by B. theobromae Pat. were studied under both in vitro culture and inocula- tion conditions, along with the pathogenicity and the ability of producing CWDEs of four post-harvest fangal pathogens（B, theobromae Pat. , Colletotrichum gloeos- porioides Penz. , Phomopsis mangiferae Ahmad and Dothiorella dominicana Pet. et Cif. ） which cause stem-end rot of mangoes. [ Result] B. theobromae Pat. was a- ble to produce polygalacturonase（PG）, pectinmethylgalacturonase（PMG）, polygalacturonic acid trans-eliminase （PGTE）, pectin methyltrans-eliminase （PMTE） and cellulase （ Cx. ） under both in vitro culture and inoculation conditions, of which activities of PG, Cx and PMG were significantly higher in than that in either PGTE or PMTE. Among three primary CWDEs, the peak of activities of PG and Cx appeared earlier and that of PMG occured later. The pathogenicity of B. theo- bromae Pat. was significantly higher than that of any other three pathogens; it is the same with the abilities of producing pectinase. [ Conclusion] This paper pro- vides theoretical bases for further exploring the mechanism of host-pathogen interaction and decreasing the post-harvest loss of mango fruits.

Gamma-glutamyl transferase 5 overexpression in cerebrovascular endothelial cells improves brain pathology,cognition,and behavior in APP/PS1 mice

In patients with Alzheimer’s disease,gamma-glutamyl transferase 5(GGT5)expression has been observed to be downregulated in cerebrovascular endothelial cells.However,the functional role of GGT5 in the development of Alzheimer’s disease remains unclear.This study aimed to explore the effect of GGT5 on cognitive function and brain pathology in an APP/PS1 mouse model of Alzheimer’s disease,as well as the underlying mechanism.We observed a significant reduction in GGT5 expression in two in vitro models of Alzheimer’s disease(Aβ_(1-42)-treated hCMEC/D3 and bEnd.3 cells),as well as in the APP/PS1 mouse model.Additionally,injection of APP/PS1 mice with an adeno-associated virus encoding GGT5 enhanced hippocampal synaptic plasticity and mitigated cognitive deficits.Interestingly,increasing GGT5 expression in cerebrovascular endothelial cells reduced levels of both soluble and insoluble amyloid-βin the brains of APP/PS1 mice.This effect may be attributable to inhibition of the expression ofβ-site APP cleaving enzyme 1,which is mediated by nuclear factor-kappa B.Our findings demonstrate that GGT5 expression in cerebrovascular endothelial cells is inversely associated with Alzheimer’s disease pathogenesis,and that GGT5 upregulation mitigates cognitive deficits in APP/PS1 mice.These findings suggest that GGT5 expression in cerebrovascular endothelial cells is a potential therapeutic target and biomarker for Alzheimer’s disease.

Some Antioxidant Enzymes among Children with Sickle Cell Disease Attending Usmanu Danfodiyo University Teaching Hospital Sokoto, North Western Nigeria

Sickle Cell Disease (SCD) is one of the most common genetic diseases in the world. It is associated with oxidative stress which occurs as a result of HbS unstable character causing a rise in the formation of free radicals. The aim of this study was to determine some antioxidant enzymes activities among patients with SCD. We investigated the superoxide dismutase (SOD), and glutathione peroxidases (GPx) levels among 60 children aged 1 - 14 years with SCD. Twenty-two age-matched non-SCD children served as control. The study subjects were divided into two groups;steady state A (n = 30) and vaso- occlusive crisis (VOC) B (n = 30). The SOD, and GPx levels were significantly lower among the SCD subjects compared to controls (p = 0.000). There were no statistically significant differences in the SOD and GPX levels between sickle cell disease patient in steady state (A) and those in crisis (B) (p = 0.998 and 0.555) respectively. There was a statistically significant difference between the SOD and GPX levels between sickle cell disease patient in steady state (A) and non-sickle cell controls (p = 0.005 and 0.000) respectively as well as between sickle cell disease patient in VOC (B) and non-sickle cell controls (p = 0.000). There were no statistically significant differences in the SOD and GPX levels of sickle disease subjects based on age, gender, maternal level of educational attainment, occupational group and income (p = 0.629 and 0.476;p = 0.382 and 0.417;p = 0.450 and 0.314 and p = 0.397 and 0.762 and p = 0.553 and 0.929) respectively. There were no statistically significant differences in the SOD and GPX levels of sickle disease subjects of Hausa/Fulani extraction versus Yoruba (p = 0.714 and 0.856), between Hausa/Fulani extraction versus Igbo (0.917 and 0.486) and between Yoruba extraction versus Igbo (p = 0.740 and 0.965) respectively. This study confirms that SCD children have lower values of antioxidant enzymes compared to controls. SOD and GPX levels in sickle cell disease patient in steady state and vaso-occlusive crisis are significantly lower compared that of non-sickle cell controls. Patients with SCD may benefit from substances with antioxidant properties which can potentially reduce the complications associated with the disease.

Optimization the Cell Wall Degrading Enzymes and Technique for Isolation of Protoplasts in Potato

Plasma membrane of plant cells is surrounded by cellulose wall and adjacent cells are joined together by a thick pectin rich matrix. Separation of plant cells and removal of the cell wall experimentally, by either a mechanical or an enzymatic process, results in the production ofprotoplast. Protoplasts are useful tools to study the uptake and transport ofmacromolecules and production of somatic hybrids. Protoplasts can be obtained from all types of actively growing young and healthy tissues. The most convenient and widely used source of plant protoplasts is leaf. Juvenile seedling tissues, cotyledons are other alternative tissues most frequently used for protoplasts isolation. All the environmental and genotypic factors, which affect the cell wall thickenings and compactness indirectly, influence the number of protoplasts recovered. Protoplasts are isolated by two methods, mechanical and enzymatic. The enzyme mixture solution of celluiose/macerozyme is used to digest the cell wall. The critical factors affecting the obtaning ofprotoplasts are the kinds of cell wall degrading enzymes, the physiological state of plant leaves, the type of osmotic stabilizers and the composition of reaction solution. With the improvement of technique and enzyme combination rate, the yield of collected protoplasts will be increased higher.

Expression of interleukin 1β converting enzyme in 5-FU induced apoptosis in esophageal carcinoma cells

AIM To study the role of interleukin 1β converting enzyme (ICE) in antitumor drug induced apoptosis in tumor cells. METHODS Morphological changes in human esophageal carcinoma Eca 109 cells after treated with 5 fluorouracil (5 FU) were observed under light and electron microscope. Expression of ICE in the tumor cells exposed to 5 FU was examined by the immunocytochemical method. RESULTS The cells treated with 5 FU displayed disappearance of nucleoli, chromatin gathering under nuclear envelope, karyorrhexis, budding and the formation of apoptotic bodies. The expression of ICE was negative in control cells, and 5 FU could induce the ICE expression in Eca 109 cells undergoing apoptosis. The number and the staining intensity of positive cells increased with the extension of action time. CONCLUSION 5 FU may induce apoptosis in human esophageal carcinoma Eca 109 cells; ICE gene may be involved in the regulation of 5 FU induced apoptosis; and ICE protein may mediate apoptosis induced by 5 FU.

Co-localization hypothesis:A mechanism for the intrapancreatic activation of digestive enzymes during the early phases of acute pancreatitis

Acute pancreatitis is generally believed to be a disease in which the pancreas is injured by digestive enzymes that it normally produces. Most of the potentially harmful digestive enzymes produced by pancreatic acinar cells are synthesized and secreted as inactive zymogens which are normally activated only upon entry into the duodenum but, during the early stages of acute pancreatitis, those zymogens become prematurely activated within the pancreas and, presumably, that activation occurs within pancreatic acinar cells. The mechanisms responsible for intracellular activation of digestive enzyme zymogens have not been elucidated with certainty but, according to one widely recognized theory （the ＂co-localization hypothesis＂）, digestive enzyme zymogens are activated by lysosomal hydrolases when the two types of enzymes become co-localized within the same intracellular compartment. This review focuses on the evidence supporting the validity of the m-localization hypothesis as an explanation for digestive enzyme activation during the early stages of pancreatitis. The findings, summarized in this review, support the conclusion that co-localization of lysosomal hydrolases with digestive enzyme zymogens plays a critical role in permitting the intracellular activation of digestive enzymes that leads to acinar cell injury and pancreatitis.

Ubiquitin-conjugating enzyme E2T knockdown suppresses hepatocellular tumorigenesis via inducing cell cycle arrest and apoptosis

BACKGROUND Hepatocellular carcinoma(HCC)is now the most common primary liver malignancy worldwide,and multiple risk factors attribute to the occurrence and development of HCC.Recently,increasing studies suggest that ubiquitinconjugating enzyme E2T(UBE2T)serves as a promising prognostic factor in human cancers,although the molecular mechanism of UBE2T in HCC remains unclear.AIM To investigate the clinical relevance and role of UBE2T in HCC development.METHODS UBE2T expression in HCC tissues from the TCGA database and its association with patient survival were analyzed.A lentivirus-mediated strategy was used to knock down UBE2T in HCC cells.qRT-PCR and Western blot assays were performed to check the effect of UBE2T silencing in HCC cells.Cell growth in vitro and in vivo was analyzed by multiparametric high-content screening and the xenograft tumorigenicity assay,respectively.Cell cycle distribution and apoptosis were determined by flow cytometry.The genes regulated by UBE2T were profiled by microarray assay.RESULTS UBE2T was overexpressed in HCC tissues compared with paired and non-paired normal tissues.High expression of UBE2T predicted a poor overall survival in HCC patients.In vitro,lentivirus-mediated UBE2T knockdown significantly reduced the viability of both SMMC-7721 and BEL-7404 cells.In vivo,the xenograft tumorigenesis of SMMC-7721 cells was largely attenuated by UBE2T silencing.The cell cycle was arrested at G1/S phase in SMMC-7721 and BEL-7404 cells with UBE2T knockdown.Furthermore,apoptosis was increased by UBE2T knockdown.At the molecular level,numerous genes were dysregulated after UBE2T silencing,including IL-1B,FOSL1,PTGS2,and BMP6.CONCLUSION UBE2T plays an important role in cell cycle progression,apoptosis,and HCC development.

New indicators in evaluation of hemolysis,elevated liver enzymes,and low platelet syndrome:A case-control study

BACKGROUND Indices such as the neutrophil-to-lymphocyte ratio(NLR),platelet-to-lymphocyte ratio(PLR),mean platelet volume(MPV),platelet distribution width(PDW),and red cell distribution width(RDW)are considered new markers of the systemic inflammatory response(SIR),and have been widely implemented for the diagnosis of patients with inflammatory diseases.These new indicators have also been widely investigated in preeclampsia(PE)but less analyzed in hemolysis,elevated liver enzymes,and low platelet(HELLP)syndrome.AIM To compare SIR markers among HELLP patients,PE only patients,and healthy gravidae.METHODS This retrospective case-control study enrolled 630 cases,including 210 patients with HELLP syndrome(HELLP group),210 patients with only PE(PE group)and 210 healthy gravidae(control group).The three groups were matched by age,parity,status of assisted reproduction,and multiple pregnancies.Birthweight,gestational age at complete blood count collection,gestational age at delivery,mode of delivery,etc.were recorded.The main indices as NLR,PLR,MPV,PDW,and RDW among the groups were compared,as well as some secondary outcomes including neutrophil,platelets,and hemoglobin.RESULTS The NLR(6.4 vs 4.3 vs 3.5),MPV(11.9 vs 11.2 vs 10.7),PDW(16.4 vs 13.3 vs 14.2),leukocyte(12.4×10^(9)/L vs 9.7×10^(9)/L vs 8.7×10^(9)/L)and neutrophil count(9.9×10^(9)/L vs 7.3×10^(9)/L vs 6.1×10^(9)/L)were highest in the HELLP group,lower in the PE group,and lowest in the control group.Both the overall comparisons between the three groups(all bP<0.01)and pairwise comparisons between every two groups elicited statistically significant differences(all dP<0.01,except control vs PE:cP<0.05 in PDW).The average lymphocyte counts were 1.4(1.1,2.0)×10^(9)/L in the HELLP group,1.6(1.3,2.0)×10^(9)/L in the PE group and 1.7(1.4,2.0)×10^(9)/L in the control group.The overall comparison of lymphocyte count within the three groups had statistically significant differences(P=0.000).The pairwise comparisons between every two groups demonstrated that the HELLP group had a lower lymphocyte count than both the PE(P=0.019)and control groups(P=0.000),but the difference between the PE and control groups was not statistically significant(P=0.432).The overall comparisons on platelet counts and the PLR among these three groups also showed statistically significant differences(both P=0.000),from low to high being those in the HELLP group(43.4×10^(9)/L,64.0),control group(180.5×10^(9)/L,103.6)and PE group(181.5×10^(9)/L,112.8).Pairwise comparisons of neither index displayed statistically significant differences between the PE and control groups(both P>0.05),while the differences in the two indices between the HELLP group and the two other groups were still statistically significant(all P=0.000).RDW values were highest in the HELLP group(14.5%[13.6,15.3]),lower in the control group(14.1%[13.5,14.8])and lowest in the PE group(13.9%[13.4,14.9]).The difference between the PE and control group did not show statistical significance(P=1.000),while RDW values in the HELLP group were higher than those in the other two groups(cP<0.05 vs control,dP<0.01 vs PE).CONCLUSION SIR markers such as NLR,RDW,MPV,and PDW were increased and PLR was decreased in HELLP.These SIR markers may become new indicators in the evaluation of HELLP syndrome.

Significance and prognostic value of lysosomal enzyme activities measured in surgically operated adenocarcinomas of the gastroesophageal junction and squamous cell carcinomas of the lower third of esophagus

AIM： To establish whether there are fundamental differences in the biochemistries of adenocarcinomas of the gastroesophageal junction （GEJ） and the squamous cell carcinomas of the lower third of the esophagus （LTE）. METHODS： Between February 1, 1997 and February 1, 2000, we obtained tissue samples at the moment of resection from 54 patients for biochemical analysis. The full set of data could be comprehensively analyzed in 47 of 54 patients＇ samples （81%）. Of these, 29 were adenocarcinomas of the GEJ Siewert type Ⅰ （n = 8）, type Ⅱ （n = 12）, type Ⅲ （n = 9）, and 18 presented as squamous cell carcinomas of the LTE. We evaluated the mean values of 11-lysosomal enzyme and 1-cytosol protease activities of the tumorous and surrounding mucosae as well as their relative activities, measured as the ratio of activity in tumor and normal tissues from the same patient. These data were further analyzed to establish the correlation with tumor localization, TNM stage （lymph-node involvement）, histological type （papillary, signet-ring cell, tubular）, state of differentiation （good, moderate, poor）, and survival （≤24 or ≥24 mo）. RESULTS： In adenocarcinomas, the activity of α-mannosidase （AMAN）, cathepsin B （CB） and dipeptidyl-peptidase Ⅰ （DPP Ⅰ） increased significantly as compared to the normal gastric mucosa. In squamous cell carcinomas of the esophagus, we also found a significant difference in the activity of cathepsin L and tripeptidyl-peptidase Ⅰ in addition to these three. There was a statistical correlation of AMAN, CB, and DPP Ⅰ activity between the level of differentiation of adenocarcinomas of the GEJ and lymph node involvement,because tumors with no lymph node metastases histologically confirmed as well-differentiated, showed a significantly lower activity. The differences in CB and DPP Ⅰ activity correlated well with the differences in survival rates, since the CB and DPP Ⅰ values of those who died within 24 mo following surgical intervention were significantly higher than of those who survived for 2 years or more. CONCLUSION： Adenocarcinomas of the GEJ form a homogenous group from a tumor-biochemical aspect, and differ from the biochemical characteristics of squamous cell carcinomas of the LTE on many points. When adenocarcinomas of the GEJs are examined at the preoperative phase, the ratio of the performed AMAN, CB, and DPP Ⅰ enzymatic activity of the tissue sample from the tumor and adjacent intact mucosa within 2 cm of the tumor may have a prognostic value even in the preoperative examination period, and may indicate that ranking of these patients into the neo-adjuvant treatment group should be considered.

Enzyme Dynamic Study on Calmodulin Ca^(++)-Mg^(++)-ATPase System of Red Blood Cells Inhibited byα-anordrin and Probimane

To clarify the possible mechanisms of α anordin and probimane on calmodulin Ca ++ Mg ++ APTase system, enzyme dynamic study was carried out by determining three dynamic parameters [the substrate concentration(ATP) response curve, dose(inhibitors) response curve and time response curve]. Our data have shown that the inhibitory rates of α anordrin and probimane are unrelated to substrate(APT) concentrations, but related to calmodulin concentrations. The inhibition of α anordrin and probimane is very quick that is completed within 1 to 5 min and can maintain more than 1 hr in the same inhibitory rates. So it is possible that α anordrin and probimane are calmodulin competitors with calmodulin like binding whose actions can occur by affecting the reaction balance of substrate and product on target enzymes of calmodulin( Ca ++ Mg ++ ATPase).

Lysosomal Enzyme Activities in Cultured Retinal Pigment Epithelial and Glial Cells of RCS Rat

Purpose: To compare the activities of acid phosphatase, N-acetyl-β-glu-cosaminidase and a- mannosidase in cultured retinal pigment epithelium (RPE)and glial cells of Royal College of Surgeons (RCS) rat with those in Long Evans(LE).Methods: The cultured RPE and glial cells of RCS and LE rat were plated into thesame 96 well microtitre, and the biochemical method in microsystem were usedfor enzyme assays.Results: The activities of acid phosphatase and N-acetyl- β-glucosaminidase arehigher by, respectively, 30% and 46% in cultured RPE of RCS rat than LE rat.The activity of a- mannosidase has no significant difference. The activities of 3enzymes in the retinal glial cells derived from RCS rats are higher than LE rat by43% to 77%.Conclusion: These results suggest that the high activities of lysosomal enzymes inRCS RPE and glial cells may play an important role in the pathogenesis of retinaldystrophy. Eye Science 1996; 12:20-27.

CATIONIC AMPHIPHILE-MEDIATED TRANSFER OF THEENZYME/PRODRUG GENE INTO C_6 GLIOMA CELLS-AN EFFECTIVE IN VITRO CHEMOSENSITIVITY SYSTEM

Objectivs Enzyme/prodrug gene therapy provides a potential strategy for the treatment of glioma.Because of the limitations of using viral vectors for clinical application, we investigated the feasibility of cationicamphiphile-mediated enzyme/prodrug gene transfer into C6 glioma cells. Methods Rat C6 glioma cells weretransfected with pUT599plasmid encoding the herpes simplex virus thymidine kinase (HSV-tk) gene via DOTAPand tested for chemosensitivity of prodrug ganciclovir (GCV). To demonstrate in vitro bystander effect, HSV-tkpositive cells were co-cultured with HSV-tk negative cells at varying proportions. Results DOTAP mediatedHSV-tk gene transfer into C6 cells showed 30%-40% of transfection efficiency. HSV-tk infected C6 glioma cellswere rendered sensitive to concentrations of GCV that were 3-4 logs lower than uninfected cells, with an IC05 of0.087μmol/L. In terms of the bystander effect, the viability of co-cultured cells decreased with increasingpopulations of HSV-tk positive cells after GCV treatment. Conclusion C6 cells were successfully transfected withthe HSV-tk gene via cationic amphiphile and displayed a strong bystander effect after GCV treatment. Cationicamphiphile - mediated HSV- tk/GCV chemosensitivity System may have promise as an intratumoral treatment forglioma.

Current-Voltage Modeling of the Enzymatic Glucose Fuel Cells

Enzymatic fuel cells produce electrical power by oxidation of renewable energy sources. An enzymatic glucose biofuel cell uses glucose as fuel and enzymes as biocatalyst, to convert biochemical energy into electrical energy. The applications which need low electrical voltages and low currents have much of the interest in developing enzymatic fuel cells. An analytical modelling of an enzymatic fuel cell should be used, while developing fuel cell, to estimate its various parameters, to attain the highest power value. In this paper an analytical model for enzymatic glucose membraneless fuel cell with direct electron transfer was developed. The adequacy of the model was estimated by comparison with fuel cells parameters. The electrical characteristics of fuel cells are interpreted using this model, based on theoretical consideration of ions transportation in solution. The influence of the hydrogen ions, glucose and enzyme concentration and also a thickness of enzyme layer on electrical parameters of a fuel cell were investigated. The electrical parameters such as a current, a voltage, a power were calculated by the model, for various parameters of the fuel cells. The model aimed to predict a hydrogen ions current, an electrical voltage and an electrical power in enzymatic fuel cell with direct electron transfer. The model reveals that increasing the rates of hydrogen ions generation and consumption leads to higher value of current, voltage and power.

Physical Modeling of the Enzymatic Glucose-Fuelled Fuel Cells

An enzymatic glucose biofuel cell uses glucose as fuel and enzymes as biocatalyst, to transform biochemical energy into electrical energy. An analytical modelling of an enzymatic biofuel cell should be used, while developing fuel cell, to estimate its various enzymatic parameters, to obtain the highest voltage feasibly. The analytical model was developed, and the open circuit voltage (OCV) calculated by the model for various parameters of the fuel cell is in agreement with the experimental results. The OCV is interpreted by using this model, based on theoretical consideration of ions transportation in the solution. The generation and consumptions of the ions near the electrodes were defined in the model by exponential approximations, with different depletion coefficients. The model reveals that increasing the rates of hydrogen ions generation and (or) consumption by enzyme or chemical reactions leads to a higher value of OCV. The model points that the OCV is saturated with a glucose concentration and increased logarithmically with a surface enzyme concentration. Hence, a low glucose concentration is sufficient to obtain adequate OCV, on the one hand, but it can be increased by increasing electrode surface porosity, on the other hand. This model can be expanded to include time and close circuit voltage.

Seropositivity rates of water channel protein 4 antibodies compared between a cell-based immunofluorescence assay and an enzyme-linked immunosorbent assay in neuromyelitis optica patients

A total of 66 samples （from 27 cases with neuromyelitis optica, 26 cases with multiple sclerosis, aa 13 cases with optic neuritis） were tested for aquaporin-4 antibody by a cell-based immunofluorescence assay and an enzyme-linked immunosorbent assay. The sensitivities and specificities of the two assays were similar. We further analyzed an additional 68 patients and 93 healthy controls using the enzyme-linked immunosorbent assay. A Kappa test showed good consistency between the two methods in terms of detection of anti-aquaporin-4 antibody in the se of neuromyelitis optica patients. No significant correlations were identified with onset age or disea duration, suggesting that aquaporin-4 antibody is a good marker for neuromyelitis optica. The enzyme-linked immunosorbent assay can be used for quantifying aquaporin-4 antibody concentrations and may be useful to dynamically monitor changes in the levels of aquaporin-4 antibody during disease duration.