Immunosurveillance function of human mast cell？

Mast cell (MC) is so widely recognized as a critical effector in allergic disorders that it can be difficult to think of MC in any other context. Indeed, MCs are multifunctional and recently shown that MCs can also act as antigen presenters as well as effector elements of human immune system. First observations of their possible role as anti-tumor cells in peri- or intra-tumoral tissue were mentioned five decades ago and a high content of MCs is considered as a favorable prognosis, consistent with this study. Believers of this hypothesis assumed them to be inhibitors of tumor development through their pro-apoptotic and -necrolytic granules e.g., granzymes and TNF-α. However, some still postulate them to be enhancers of tumor development through their effects on angiogenesis due to mostly tryptase. There are also some data suggesting increased MC density causes tumor development and indicates bad prognosis. Furthermore, since MC-associated mediators have shown to influence various aspects of tumor biology, the net effect of MCs on the development/ progression of tumors has been difficult to evaluate. For instance, chymase induces apoptosis in targets; yet, tryptase, another MC protease, is a well-known mitogen. MCs with these various enzyme expression patterns may mediate different functions and the predominant MC type in tissues may be determined by the environmental needs. The coexistence of tryptase-expressing MCs (MCT) and chymase and tryptase-expressing MCs (MCTC) in physiological conditions reflects a naturally occurring balance that contributes to tissue homeostasis. We have recently discussed the role and relevance of MC serine proteases in different bone marrow diseases.     

Structural basis of human γ-secretase assembly

The four-component intramembrane protease γ-secretase is intricately linked to the development of Alzheimer’s disease. Despite recent structural advances, the transmembrane segments (TMs) of γ-secretase remain to be specifically assigned. Here we report a 3D structure of human γ-secretase at 4.32-Å resolution, determined by single-particle, electron cryomicroscopy in the presence of digitonin and with a T4 lysozyme fused to the amino terminus of presenilin 1 (PS1). The overall structure of this human γ-secretase is very similar to that of wild-type γ-secretase determined in the presence of amphipols. The 20 TMs are unambiguously assigned to the four components, revealing principles of subunit assembly. Within the transmembrane region, PS1 is centrally located, with its amino-terminal fragment (NTF) packing against Pen-2 and its carboxyl-terminal fragment (CTF) interacting with Aph-1. The only TM of nicastrin associates with Aph-1 at the thick end of the TM horseshoe, and the extracellular domain of nicastrin directly binds Pen-2 at the thin end. TM6 and TM7 in PS1, which harbor the catalytic aspartate residues, are located on the convex side of the TM horseshoe. This structure serves as an important framework for understanding the function and mechanism of γ-secretase.Alzheimer’s disease (AD), characterized by formation of β-amyloid plaque in the brain of a patient, is closely associated with γ-secretase (1, 2). Amyloid precursor protein (APP) is processed by β-secretase in the extracellular space to produce a membrane-tethered fragment known as C99 (3). APP C99 then undergoes sequential cleavages by γ-secretase, generating a series of β-amyloid peptides (Aβ) exemplified by Aβ42 and Aβ40 (4, 5). Among all Aβs, Aβ42 is particularly prone to aggregation, resulting in formation of β-amyloid plaque and presumably contributing to the development of AD (6).Mature γ-secretase contains four components: presenilin, Pen-2, nicastrin, and Aph-1. The catalytic subunit presenilin is predicted to contain nine transmembrane segments (TMs), with two catalytic aspartate residues on TM6 and TM7. During assembly of γ-secretase, presenilin undergoes an autocatalytic cleavage to yield two polypeptide fragments, NTF (comprising TMs 1–6) and CTF (comprising TMs 7–9) (7, 8). PS1 is the target of most mutations derived from early onset familial Alzheimer’s disease patients (1). The largest component nicastrin has only one TM but contains a highly glycosylated extracellular domain (ECD), which presumably recognizes the amino terminus of substrate protein (9–11). The smallest component Pen-2 is thought to be required for the autocatalytic maturation of presenilin and γ-secretase activity (12, 13). Aph-1, required for assembly of γ-secretase (14), appears to have a previously unidentified fold with seven predicted TMs.The assembly and intersubunit interactions of γ-secretase constitute an important basis for its mechanistic understanding and have been extensively investigated during the past decade. As the central component of γ-secretase, PS1 was shown to interact with both Pen-2 and Aph-1 and form distinct subcomplexes (15–21). The only TM of nicastrin was thought to bind Aph-1 and contribute to interactions with PS1. Rationalization of these biochemical findings and other functional observations requires detailed 3D structural information on γ-secretase.In contrast to rapid accumulation of biochemical and functional data on γ-secretase, structural determination has been slow to emerge, largely due to the technical challenges associated with expression and manipulation of the intact γ-secretase. Several EM analyses have yielded low-resolution images of γ-secretase (22–27), with the overall shapes diverging from each other. Investigation of γ-secretase by other biophysical methods produced an NMR structure of the presenilin CTF (28) and X-ray structures of an archaeal homolog of presenilin (29) and a eukaryotic homolog of nicastrin (30).The high-resolution cryo-electron microscopy (cryo-EM) structure of human γ-secretase, determined at 4.5-Å resolution and in the presence of amphipols, revealed an overall architecture that is qualitatively different from all previous structures (31). The EM densities allowed identification of 19 TMs and construction of an atomic model for the ECD (31). However, these densities lacked connectivity between TMs and exhibited few side-chain features in the TMs, disallowing specific TM assignment to the four components. The use of amphipols also raises the question of whether the structure of human γ-secretase is dependent upon the choice of detergent used. In this study, we address these concerns and report, to our knowledge, the first structure of an intact γ-secretase with all TMs assigned.     

Possible stem cell origin of human cholangiocarcinoma

MM:To investigate the expression of CD34 and c-kit(receptor of stem cell factor)in cholangiocarcinoma. METHODS:Fifteen cases of intrahepatic cholangiocarcinoma and 17 cases of extrahepatic cholangiocarcinoma were studied in this experiment.Using Envision detection system,paraffin- embedded sections of the resected cholangiocarcinoma tissue were stained with antibodies against CD34 and c- kit,respectively.The sections were counterstained with hematoxylin,and the results were examined under light microscope.Normal tonsil and mammary tissues were used as positive controls for CD34 and c-kit,respectively. RESULTS:CD34 was positive in all sections,but only in capillary endothelial cells of tumor tissue.No cholangiocarcinoma cells were positive for CD34.In one case of extrahepatic cholangiocarcinoma,a few tumor cells(about 5%)were immunoreactive with c-kit. CONCLUSION:CD34 or c-kit positive cells in liver tissue may represent liver stem cells,as they can differentiate into mature biliary cells in vitro.The expression of c-kit by some cholangiocarcinoma cells suggests that cholangiocarcinoma might originate from liver stem cells.However,other mechanisms of hepatocarcinogenesis,such as de-differentiation of mature cholangiocytes,may also exist.     

Effect of staurosporine on cycle of human gastric cancer cells

AIM:TO study the effect of staurosporine (ST) on the cellcycle of human gastric cancer cell lines MGC803 andSGC7901.METHODS:Cell proliferation was evaluated by trypan bluedye exclusion method.Apoptotic morphology was observedunder a transmission electron microscope.Changes of cellcycle and apoptotic peaks of cells were determined by flowcytometry.Expression of p21~(WAFl)gene was examined usingimmunohistochemistry and RT-PCR.RESULTS:The growth of MGC803 and SGC7901 cells wasinhibited by ST.The inhibitory concentrations against 50?lls (IC_(50)) at 24 h and 48 h were 54 ng/ml and 23 ng/ml forMGC803,and 61 ng/ml and 37 ng/ml for SGC7901.Typicalapoptotic bodies and apoptotic peaks were observed 24 hafter cells were treated wth ST at a concentration of 200ng/ml.The percentage of cells at G_0/G_1 phase was decreasedand that of cells at G_2/M was increased significantly in thegroup treated wth ST at the concentrations of 40 ng/ml,60 ng/ml,100 ng/ml for 24 h,compared with the controlgroup (P<0.01).The expression levels of p21~(WAFl)gene inboth MGC803 and SGC7901 cells were markedly up-regulatedafter treatment with ST.CONCLUSION:ST can cause arrest of gastric cancer cellsat G_2/M phase,which may be one of the mechanisms thatinhibit cell proliferation and cause apoptosis in these cells.Effect of ST on cells at G_2/M phase may be attributed to theup-regulattion of p21~(WAFl) gene.     

Is human chorionic gonadotropin directly involved in the regulation of human implantation?

The regulation of human implantation is not fully understood. hCG as one of the earliest embryonal signals may be a major regulator in the parakrine embryo-endometrial communication. The expression of full-length hCG/LH-receptor mRNA could be demonstrated in human endometrium throughout the follicular and secretory phase of the menstrual cycle. In contrast, in early pregnancy decidua only truncated variants could be detected. To investigate direct effects of hCG on the human endometrium, an intrauterine microdialysis device was developed to measure parakrine mediators within the uterine cavity in vivo. Using this system, hCG was applied in the secretory phase and the endometrial response was evaluated. The administration of hCG (500 IU/ml) provoked a significant inhibition of intrauterine IGFBP-1 and M-CSF, while LIF, VEGF and MMP-9 were significantly stimulated. Taken together there appear to be multiple direct effects of hCG on the endometrium that precede the classical endocrine role of the hormone.     

Assessment of β-cell function in human patients

This review focuses on the methods accessing β-cell function. β-cell failure is the critical step in the development of type 2 diabetes. Therefore, assessment of β-cell function is an important part of the evaluation and treatment of diabetic patients. However, it is not easy because of complex interaction between multiple tissues. Several parameters should be considered, such as glucose level and insulin sensitivity of diverse insulin target tissues to assess β-cell function. To overcome these difficulties, several invasive or non-invasive methods have been developed to assess β-cell function for clinical or research purposes.     

Assessment of β-cell function in human patients

This review focuses on the methods accessing β-cell function. β-cell failure is the critical step in the development of type 2 diabetes. Therefore, assessment of β-cell function is an important part of the evaluation and treatment of diabetic patients. However, it is not easy because of complex interaction between multiple tissues. Several parameters should be considered, such as glucose level and insulin sensitivity of diverse insulin target tissues to assess β-cell function. To overcome these difficulties, several invasive or non-invasive methods have been developed to assess β-cell function for clinical or research purposes.     

Effects of α-mangostin on apoptosis induction of human colon cancer

AIM: To investigate the effect of α-mangostin on the growth and apoptosis induction of human colon cancer cells.METHODS: The three colorectal adenocarcinoma cell lines tested (COLO 205, MIP-101 and SW 620) were treated with α-mangostin to determine the effect on cell proliferation by MTT assay, cell morphology, chromatin condensation, cell cycle analysis, DNA fragmentation, phosphatidylserine exposure and changing of mitochondrial membrane potential. The molecular mechanisms of α-mangostin mediated apoptosis were further investigated by Western blotting analysis including activation of caspase cascade, cytochrome c release, Bax, Bid, p53 and Bcl-2 modifying factor.RESULTS: The highest inhibitory effect of α-mangostin on cell proliferation of COLO 205, MIP-101 and SW 620 were 9.74 ± 0.85 μg/mL, 11.35 ± 1.12 μg/mL and 19.6 ± 1.53 μg/mL, respectively. Further study showed that α-mangostin induced apoptotic cell death in COLO 205 cells as indicated by membrane blebbing, chromatin condensation, DNA fragmentation, cell cycle analysis, sub-G1 peak (P < 0.05) and phosphatidylserine exposure. The executioner caspase, caspase-3, the initiator caspase, caspase-8, and caspase-9 were expressed upon treatment with α-mangostin. Further studies of apoptotic proteins were determined by Western blotting analysis showing increased mitochondrial cytochrome c release, Bax, p53 and Bmf as well as reduced mitochondrial membrane potential (P < 0.05). In addition, up-regulation of tBid and Fas were evident upon treatment with α-mangostin (P < 0.01).CONCLUSION: α-Mangostin may be effective as an anti-cancer agent that induced apoptotic cell death in COLO 205 via a link between extrinsic and intrinsic pathways.     

Effects of α-mangostin on apoptosis induction of human colon cancer

AIM:To investigate the effect of α-mangostin on the growth and apoptosis induction of human colon cancer cells.METHODS:The three colorectal adenocarcinoma cell lines tested (COLO 205,MIP-101 and SW 620) were treated with α-mangostin to determine the effect on cell proliferation by MTT assay,cell morphology,chromatin condensation,cell cycle analysis,DNA fragmentation,phosphatidylserine exposure and changing of mitochondrial membrane potential.The molecular mechanisms of α-mangostin mediated apoptosis were fu...     

Peroxisomal localization of α-oxidation in human liver

It was found that -oxidation in rat liver is a peroxisomal process, consisting of an activation, a 2-hydroxylation, and a reaction leading to the production of formate. -Oxidation of 3-methyl-substituted fatty acids was quantified by measuring the production of formate and CO2, and the production of a 2-hydroxy-3-methylacyl-CoA-intermediate was demonstrated. We wanted to extend these findings to human liver, in view of the controversy over the subcellular localization of -oxidation in man.In homogenates from human liver, rates of -oxidation were highest when measured in the presence of ATP, CoA, Mg2+, 2-oxoglutarate, ascorbate and Fe2+. In subcellular fractions prepared by differential centrifugation and in fractions obtained after subfractionation of a peroxisome-enriched fraction on a Percoll gradient, production of formate and of a 2-hydroxy-3-methylacyl-CoA intermediate coincided with the peroxisomal marker catalase. In broken fractions, production of CO2 was almost negligible as compared to formate production.We conclude from our findings that in human liver, as in rat liver, -oxidation of 3-methyl-substituted fatty acids is a peroxisomal process, consisting of an activation reaction, a 2-hydroxylation reaction and a reaction or reactions leading to the generation of formate as a primary product which is subsequently converted to CO2. Furthermore activation, 2-hydroxylation and generation of formate appear to be coupled (see Casteels et al 1996). These data demonstrate that Refsum disease should indeed be classified as a peroxisomal disease.     

In vitro effects of recombinant human growth hormone on growth of human gastric cancer cell line BGC823 cells

AIM:To study the effects of recombinant human growthhormone (rhGH) on growth of human gastric cancer cellline in vitro.METHODS:Experiment was divided into control group,rhGH group,oxaliplatin (L-OHP) group and rhGH L-OHPgroup.Cell inhibitory rate,cell cycle,cell proliferation index(PI) and DNA inhibitory rate of human gastric cancer lineBGC823,at different concentrations of rhGH treatment werestudied by cell culture,MTT assay and flow cytometry.RESULTS:The distinctly accelerated effects of rhGH onmultiplication of BGC823 cell line were not found in vitro.There was no statistical significance between rhGH groupand control group,or between rhGH L-OHP group and L-OHP group (P>0.05).The cell growth curve did not rise.Cell inhibitory rate and cells arrested in G_0-G_1 phase wereobviously increased.Meanwhile,cells in S phase and PIwere distinctly decreased and DNA inhibitory rate wasobviously increased in rhGH L-OHP group in comparisonwith control group and rhGH group,respectively (P<0.01).Cell inhibitory rate showed an increasing trend and PIshowed a decreasing trend in rhGH L-OHP group comparedwith L-OHP group.CONCLUSION:In vitro rhGH does not accelerate themultiplication of human gastric cancer cells.It may increasethe therapeutic efficacy when it is used in combination withanticancer drugs.     

Clinical features of human intestinal capillariasis in Taiwan

Human intestinal capillariasis is a rare parasitosis that wasfirst recognized in the Philippines in the 1960 s.Parasitosisis a life threatening disease and has been reported fromThailand,Japan,South of Taiwan (Kaoh-Siung),Korea,Iran,Egypt,Italy and Spain.Its clinical symptoms arecharacterized by chronic diarrhea,abdominal pain,borborygmus,marked weight loss,protein and electrolyteloss and cachexia.Capillariasis may be fatal if earlytreatment is not given.We reported 14 cases living in ruralareas of Taiwan.Three cases had histories of travelling toThailand.They might have been infected in Thailand whilestayed there.Two cases had the diet of raw freshwaterfish before.Three cases received emergency laparotomydue to peritonitis and two cases were found of enteritiscystica profunda.According to the route of transmission,freshwater and brackish-water fish may act as theintermediate host of the parasite.The most simple andconvenient method of diagnosing capillariasis is stoolexamination.Two cases were diagnosed by histology.Mebendazole or albendezole 200 mg orally twice a day for20-30 d is the treatment of choice.All the patients werecured,and relapses were not observed within 12 mo.     

Inhibition of transfected PTEN on human colon cancer

AIM:To study the inhibitory effect of transfected PTEN onLoVo cells.METHODS:Human PTEN cDNA was transferred into LoVocells via lipofectin and PTEN mRNA levels and its expressionwere analyzed by Western blot and flow cytometry.Beforeor after transfection,the effects of 5-Fu on inhibiting cellproliferation and inducing apoptosis were measured byflow cytometry,DNA bands and MTF.RESULTS:PTEN transfection significantly up-regulated PTENexpression in LoVo cells.5-Fu inhibited cell proliferationand induced apoptosis in transfected LoVo cells.CONCLUSION:Transfected PTEN can remarkably up-regulatePTEN expression in LoVo cells and promote the apoptosis.PTEN transfection is associated with 5-Fu treatment effectand has a cooperatively cytotoxic effect.     

Establishment and application of experimental model of human fetal hepatocytes: protective effects of silybin and polyporus umbelalus polysaccharides on human fetal hepatocytes

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Retrovirus—mediated gene transfer of human endostatin inhibits growth of human liver carcinoma cells SMMC7721 in nude mice

AIM: To study the effect of human endostatin mediated by retroviral gene transfer on the growth of human hepatocarcinoma cell line SMMC7721 in nude mice. METHODS: Human endostatin gene together with rat serum albumin signal peptide was transferred into human liver carcinoma SMMC7721 cells by retroviral vector pLncx to build a stable transfectant (SMMC-endo). PCR and Western blot analysis were used to verify the transfection and secretion of human endostatin gene in SMMC7721 cells. The endothelial cell proliferation assay in vitro was conducted to test the biological activity of the expressed human endostatin. The inhibitory effect of endostatin expressed by transfected SMMC7721 on the growth rates of tumor cells in vivo was observed. The mean microvessel density in the specimen was also counted. RESULTS: PCR amplification proved that the genome of SMMC-endo cells contained a 550bp specific fragment of endostatin gene. Western blot analysis confirmed the secretion of human endostatin gene in the conditioned medium of transfected SMMC-endo cells. The endothelial proliferation assay showed that the conditioned medium of SMMC-endo cells significantly inhibited the proliferation of human umbilical vein endothelial cells by 48 %, significantly higher than that of SMMC-pLncx (10.2 %, P<0.01). In vitro experiments revealed that only in 3 out of 5 mice tumors were formed and the mean size of flank tumors from SMMC-endo cells was 94.5 % smaller than that from the control SMMC-pLncx cells 22 days after tumor inoculation (P<0.001). The mean microvessel density in tumor samples from SMMC-endo cells was only 8.6+/-1.1, much fewer than that of 22.6+/-4.5 from SMMC-pLncx cells (P<0.01). CONCLUSION: Human endostatin mediated by retroviral gene transfer can inhibit human liver carcinoma cell SMMC7721 growth in nude mice.     

Observation on migration of larvae of Hypoderma lineatum in human body.

A 19-year-old female peasant who had a histroy of contact with domestic animalscomplained of wandering bolus with paresthesia and itching in her inner lateral legs inthe summer of 1979. The bolus was soybean-sized, emerged and disappeared alterna-     

Function of human Rh based on structure of RhCG at 2.1??

In humans, NH₃ transport across cell membranes is facilitated by the Rh (rhesus) family of proteins. Human Rh C glycoprotein (RhCG) forms a trimeric complex that plays an essential role in ammonia excretion and renal pH regulation. The X-ray crystallographic structure of human RhCG, determined at 2.1 Å resolution, reveals the mechanism of ammonia transport. Each monomer contains 12 transmembrane helices, one more than in the bacterial homologs. Reconstituted into proteoliposomes, RhCG conducts NH₃ to raise internal pH. Models of the erythrocyte Rh complex based on our RhCG structure suggest that the erythrocytic Rh complex is composed of stochastically assembled heterotrimers of RhAG, RhD, and RhCE.     

Effect of human benaviour on the familial aggregation of schistosomiasis cases.

The statistic G was performed for testing familial aggregation on survey data of schistosomiasiscases in Zhouhe Township,Weishan County,Yunnan Province.The T value calculated from the data of1987 was 8.03 and the P value was much less than 0.01,suggesting a high familial aggregation ofschistosomiasis cases in the Township.Three natural villages of the Township were selected for thesame purpose to collect data before and after the reformation of the Agricultural Administration