Association between a functional genetic polymorphism (rs2230199) and age-related macular degeneration risk: a meta-analysis

The association between the rs2230199 C>G single nucleotide polymorphism (SNP) in complement component 3 and age-related macular degeneration (AMD) risk has been examined extensively but the results are not consistent among studies. The aim of this study was to perform a meta-analysis of all available studies on this SNP in relation to AMD. The comprehensive databases of PubMed, Medline, Web of Knowledge, CNKI, and Google Scholar were searched for case-control studies investigating the association between the rs2230199 polymorphism and AMD susceptibility. ORs with 95%CIs were estimated to assess the association. Sensitivity analysis, test of heterogeneity, cumulative meta-analysis, and assessment of bias were also performed. A total of 15 published studies including 5593 cases and 5181 controls were used in this meta-analysis. Overall, the rs2230299 SNP was significantly associated with the risk of AMD in the overall population under the additive model (OR = 1.571, 95%CI = 1.414-1.745, P = 0.000), dominant model (OR = 1.681, 95%CI = 1.521-1.858, P = 0.000), and allelic model (OR = 1.597, 95%CI = 1.470-1.734, P = 0.000). In the subgroup analysis by ethnicity, the same results were found in Caucasian populations, while no significant correlations were found in Asian populations for all comparison models. In conclusion, our meta-analysis provides evidence that the rs2230199 polymorphism contributes to the development of AMD. Further large-scale multicenter epidemiological studies are warranted to confirm this finding.

First Report of Valsa leucostoma Causing Valsa Canker of Pyrus communis (cv. Duchess de' Angouleme) in China

Pear is a popular fruit in the world market, and has been widely cultivated in China. Since 2008, a severe canker disease has consistently been observed on 20-year-old pear trees (Pyrus communis cv. Duchess de' Angouleme) grown in a nursery in Xingcheng, Liaoning Province, China. Observed symptoms include brown elongated ulcerative lesions (more than 20 cm in length in general), with red brown conidia produced on wet lesions. Reductions in tree vigor and yield were observed for infected trees. Tree mortality was observed for severe infections. To diagnose the pathogen, 15 canker samples were collected from five pear trees in April, 2012. Bark pieces (3 to 5 mm) taken from the border of healthy and diseased tissue were surface-disinfected with 0.1% mercury bichloride and 75% ethanol for 45 s, and placed on potato dextrose agar (PDA) medium at 25°C in darkness. Fungal colonies with a common colony morphology were consistently recovered from three samples. These fungal colonies were initially white, becoming olive green in 3 days. Conidia produced on colonies were hyaline, allantoid, and single-celled with average length × width of 6.04 (5.43 to 6.59) × 0.65 (0.51 to 0.73) μm, which were consistent with descriptions of Valsa leucostoma (1). Genomic DNA was extracted from a representative isolate F-LN-32b, and subjected to PCR amplification of the internal transcribed spacer region (ITS), β-tubulin gene, and EF1 gene using the primer pairs ITS1/ITS4, Bt2a/Bt2b and EF1-728F/EF1-986R (3), respectively. Sequence alignment of the amplified fragments with the deposited data in NCBI showed that sequences of EF1, ITS, and β-tubulin (GenBank Accession No. KF293296 to KF293298, respectively) of isolate F-LN-32b had the highest similarity of 99% to those of V. leucostoma strain 32-2w (JQ900340, JN584644, and JQ900374), and suggested that isolate F-LN-32b is a V. leucostoma strain. Pathogenicity tests was carried out by placing a 5-mm-diameter, 2-day-old mycelium agar plug of isolate F-LN-32b onto a punched bark hole of a detached 1-year-old pear shoot after it was surface disinfested with ethanol. Inoculated shoots were incubated at 25°C in plastic containers covered with plastic film. Pathogenicity assays were conducted on 18 pear varieties (cvs. Qiuyue, Jinshui 2, Hohsui, Huali 1, Cuiguan, Shinseiki, Xuehua, Dangshansu, Zaosu, Hongxiangsu, Yuluxiang, Nanguoli, Xizilv, Bartlett, Huanghua, Huashan, Duchess de' Angouleme, and Packham's) collected from a nursery in Wuhan, Hubei Province, China. Six shoots were inoculated for each variety and the assay was conducted three times. All inoculated shoots developed the typical canker symptoms after 6 days post inoculation (dpi) and sporulated at 25 dpi while the control shoots inoculated with non-colonized PDA plugs remained asymptomatic. Isolates recovered from inoculated samples were of the same morphology and ITS sequence as F-LN-32b. Based on these results, V. leucostoma was determined as the pathogen responsible for the Valsa canker disease on pear. Valsa mali var. pyri was identified as the only pathogen causing Valsa canker disease on pear in China (2). To our knowledge, this is the first report of V. leucostoma causing a canker disease on pear in China. References: (1) G. C. Adams et al. Australas. Plant Pathol. 35:521, 2006. (2) X. L. Wang et al. Mycologia 103:317, 2011. (3) T. J. White et al. Pages 315-322 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990.

The First Report of Leaf Spots in Aloe vera Caused by Nigrospora oryzae in China

Aloe vera L. var Chinese (Haw) Berg is a popular ornamental plant cultivated worldwide, whose extracts are used in cosmetics and medicine. Aloe plants are commonly affected by leaf spot disease caused by Alternaria alternata in Pakistan, India, and the United States (1). An outbreak of Alternaria leaf spot recently threatened aloe gel production and the value of ornamental commerce in Louisiana (1). During the summer of 2011, leaf spot symptoms were observed on A. vera plants growing in several greenhouses and ornamental gardens in Wuhan, Hubei Province, China. In two of the greenhouses, disease incidence reached 50 to 60%. The initial symptoms included chlorotic and brown spots that expanded to 2 to 4 mm in diameter and became darker with age. Lesions also developed on the tips of 30 to 50% of the leaves per plant. In severe infections, the lesions coalesced causing the entire leaf to become blighted and die. In September of 2012 and February of 2013, 10 symptomatic A. vera leaves were collected randomly from two greenhouses and gardens in Wuhan. A fungus was consistently recovered from approximately 80% of the tissue samples using conventional sterile protocols, and cultured on potato dextrose agar (PDA). The colonies were initially white, becoming grey to black, wool-like, and growing aerial mycelium covering the entire petri dish (9 cm in diameter) plate within 5 days when maintained in the dark at 25°C. The conidia were brown or black, spherical to subspherical, single celled (9 to 13 μm long × 11 to 15 μm wide), borne on hyaline vesicles at the tip of conidiophores. The conidiophores were short and rarely branched. These colonies were identified as Nigrospora oryzae based on the described morphological characteristics of N. oryzae (2). Genomic DNA was extracted from a representative isolate, LH-1, and the internal transcribed spacer region was amplified using primer pair ITS1/ITS4 (3). A 553-bp amplicon was obtained and sequenced. The resulting nucleotide sequence (GenBank Accession No. KC519728) had a high similarity of 99% to that of strain AHC-1 of N. oryzae (JQ864579). Pathogenicity tests for strain LH-1 were conducted in triplicate by placing agar pieces (5 mm in diameter) containing 5-day-old cultures on A. vera leaves. Four discs were placed on each punctured surface of each leaf. Noncolonized PDA agar pieces were inoculated as controls. Leaves were placed in moist chambers at 25°C with a 12-h photoperiod. After 3 days, the inoculated leaves showed symptoms similar to those observed in the greenhouses. N. oryzae was reisolated from these spots on the inoculated leaves. No visible symptoms developed on the control leaves. The pathogenicity tests were performed twice with the same results. Based on the results, N. oryzae was determined as a pathogen responsible for the leaf spots disease on A. vera. N. oryzae has been described as a leaf pathogen on fig (Ficus religiosa), cotton (Gossypium hirsutum) and Kentucky bluegrass (Poa pratensis) (4), and to our knowledge, this is the first report of N. oryae causing leaf spot disease on A. vera worldwide. References: (1) W. L. da Silva and R. Singh. Plant Dis. 86:1379, 2012. (2) M. B. Ellis. Dematiaceous Hyphomycetes, CAB, Kew, Surrey, England, 1971. (3) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990. (4) L. X. Zhang et al. Plant Dis. 96:1379, 2012.

Mesenchymal stem cells differentially mediate regulatory T cells and conventional effector T cells to protect fully allogeneic islet grafts in mice

AIMS/HYPOTHESIS

Limited information is available on the cellular interactions between regulatory T (T(reg)) cells and mesenchymal stem cells (MSCs). In particular, a direct effect of MSCs on the survival and proliferation of T(reg) cells has not been demonstrated.

METHODS

We investigated the effects of MSCs on effector T (T(eff)) cells and T(reg) cells, and the molecular mechanisms involved in the distinct regulation of these two cell populations by MSCs in vivo and in vitro.

RESULTS

We show that MSCs are capable of selectively suppressing T(eff) cells and fostering the generation of T(reg) cells. T(eff) cells, but not T(reg) cells, fail to respond to IL-2 and undergo profound apoptosis in the presence of MSCs. The differential regulations of these two T cell subsets by MSCs are associated with their distinct expressions of CD25, with MSCs specifically reducing the expression of CD25 on T(eff) and sparing T(reg) cells intact. In vivo, the administration of MSCs significantly delays the rejection of allogeneic islet grafts in adaptive transferred recipients by favouring the induction of T(reg) cells. In this model, MSCs inhibit the proliferation and development of alloreactive T(eff) but potently enhance the induction of T(reg) cells.

CONCLUSIONS/INTERPRETATION

We demonstrate that MSCs are capable of regulating T(eff) and T(reg) cells differentially in vitro. MSCs inhibit T(eff) cells by inducing apoptosis and impairing the proliferative response to IL-2 in T(eff) cells, but favour the survival and expansion of T(reg) cells. This result is further demonstrated in mice that have undergone allogeneic islet transplantation, in which MSCs suppress alloreactive T(eff) cells while favouring the induction of T(reg) cells, thus protecting the islet allografts from rejection.

Clopidogrel 150 vs. 75 mg day(-1) in patients undergoing percutaneous coronary intervention: a meta-analysis

BACKGROUND

Whether an increase in the daily oral maintenance dose of clopidogrel may improve clinical outcomes in patients undergoing percutaneous coronary intervention (PCI) is still debated.

OBJECTIVES

This meta-analysis aimed to estimate the relative effect of a 150- vs. 75-mg daily maintenance dosage of clopidogrel on clinical and laboratory end-points in patients undergoing PCI.

METHODS

We searched electronic and printed sources (up to 14 December 2010) for both randomized control trials and observational studies satisfying the predefined inclusion criteria.

RESULTS

We retrieved 12 reports of studies including a total of 23,814 patients. Clopidogrel, 150 mg day(-1), was associated with significant reductions in major adverse cardiac and/or cerebrovascular events (odds ratio [OR], 0.67; 95% confidence interval [CI], 0.48-0.94), myocardial infarction (OR, 0.72; 95% CI, 0.60-0.86), target vessel revascularization (OR, 0.27; 95% CI, 0.12-0.62) and stent thrombosis (OR, 0.64; 95% CI, 0.53-0.77) and decreased adenosine diphosphate-induced maximal platelet aggregation. However, as compared with 75 mg day(-1), the 150-mg daily maintenance dosage significantly increased the risk of minor bleeding (OR, 1.21; 95% CI, 1.08-1.36).

CONCLUSION

As compared with the currently recommended 75-mg day(-1) maintenance dosage of clopidogrel, the 150-mg day(-1) dosage can reduce major adverse cardiac and/or cerebrovascular events but may increase the risk of minor bleeding.

Relationships among acylation stimulating protein, adiponectin and complement C3 in lean vs obese type 2 diabetes

OBJECTIVE

The purpose of this study was to determine the relationships between adipocyte hormones acylation stimulating protein (ASP), adiponectin, complement C3 (C3) (ASP precursor) and insulin, C-reactive protein (CRP), lipid profiles and insulin resistance in lean vs obese type 2 diabetes subjects.

SUBJECTS

Lean type 2 diabetes subjects (DL n = 27) vs obese type 2 diabetes subjects (DO n = 55) were compared to age-matched nondiabetic groups (Obese, OB n = 55 and control, CTL n = 50).

RESULTS

The DO group demonstrated significant increases in plasma ASP and C3 with decreases in plasma adiponectin as compared to CTL. Interestingly, these increases in ASP and C3 were as high, or greater, in the DL group in spite of normal weight. By contrast adiponectin in the DL group was comparable to CTL, in spite of marked insulin resistance. C3 correlated with insulin, glucose and homeostasis model assessment of insulin resistance (HOMA-IR); ASP correlated with body mass index (BMI), glucose, insulin and plasma lipid parameters (non-esterified fatty acids (NEFA), triglyceride, cholesterol and apolipoprotein B). Adiponectin correlated with BMI, glucose, NEFA, triglyceride, high-density lipoprotein cholesterol and apolipoprotein A1 but not HOMA-IR, ASP or C3. CRP correlated only with HOMA-IR.

CONCLUSION

Increased ASP and C3 are both associated with diabetes and related lipid factors but are not regulated coordinately. Adiponectin appears to be more closely related to body size (decreased in obese subjects) than insulin resistance in these subjects.

Role of glucan and surface protein BAD1 in complement activation by Blastomyces dermatitidis yeast

Our previous studies showed that Blastomyces dermatitidis yeast activates the human complement system, leading to deposition of opsonic complement fragments onto the yeast surface. This report examines the influence of altered surface expression of glucan or BAD1 protein (formerly WI-1) on the yeast's ability to activate and bind C3. Compared to the wild type, a glucan-deficient mutant yeast delayed initiation of C3 deposition and reduced C3-binding capacity by 50%. Linkage of baker's-yeast beta-glucan to the glucan-deficient yeast restored initial C3 deposition kinetics to the wild-type level and partially restored C3-binding capacity, suggesting that beta-glucan is an initiator of complement activation and a C3 acceptor. The role of BAD1 in B. dermatitidis yeast-complement interaction was also assessed. BAD1 knockout yeast initiated faster C3 deposition and increased C3-binding capacity compared to the wild-type yeast or a BAD1-reconstituted yeast, suggesting either a lack of an intrinsic ability in BAD1 or an inhibitory role of BAD1 in complement activation and binding. However, both complement activation and the capacity for C3 binding by the wild-type yeast were enhanced in normal human serum supplemented with an anti-BAD1 monoclonal antibody (MAb) or in immune sera from blastomycosis patients. Microscopic analysis revealed that more initial C3-binding sites were formed on yeast in the presence of both naturally occurring complement initiators and exogenous anti-BAD1 MAb, suggesting that anti-BAD1 antibody enhanced the ability of B. dermatitidis yeast to interact with the host complement system. Thus, glucan and BAD1 have distinctly different regulatory effects on complement activation by B. dermatitidis.

Complement is essential for protection by an IgM and an IgG3 monoclonal antibody against experimental, hematogenously disseminated candidiasis

The incidence of life-threatening, hematogenously disseminated candidiasis, which is predominantly caused by Candida albicans, parallels the use of modern medical procedures that adversely affect the immune system. Limited antifungal drug choices and emergence of drug-resistant C. albicans strains indicate the need for novel prevention and therapeutic strategies. We are developing vaccines and Abs that enhance resistance against experimental candidiasis. However, the prevalence of serum anti-Candida Abs in candidiasis patients has led to the misconception that Abs are not protective. To explain the apparent discrepancy between such clinical observations and our work, we compared functional activities of C. albicans-specific protective and nonprotective mAbs. Both kinds of Abs are agglutinins that fix complement and are specific for cell surface mannan, but the protective Abs recognize beta-mannan, and the nonprotective Ab is specific for alpha-mannan. By several indirect and direct measures, the protective mAbs more efficiently bind complement factor C3 to the yeast cell than do nonprotective Ab. We hypothesize that the C3 deposition causes preferential association of blood-borne fungi with host phagocytic cells that are capable of killing the fungus. We conclude from these results that the protective potential of Abs is dependent on epitope specificity, serum titer, and ability to rapidly and efficiently fix complement to the fungal surface. The mechanism of protection appears to be associated with enhanced phagocytosis and killing of the fungus.

[Intracellular potential changes in crucian carps Mauthner cells evoked by vagal sensory inputs]

In the present experiments, microelectrode recording technique was used to explore the electrophysiological properties of Mauthner cells (M-cells) with stimuli applied to the right vagus. Direct stimulation of the right vagus evoked short-latency, long-lasting, graded, and complex postsynaptic potentials (PSPs) on both Mauthner cell bodies in crucian carp, which are stimulus strength- and frequency- dependent. The evoked PSPs reduced the amplitudes of the antidromic action potentials. After intramuscular injection of strychnine, both amplitude and averaged duration of the PSPs increased, on which two or more action potentials were superimposed. The results suggest that the afferent pathways from vagus to M-cells are mediated by several neuron chains with different numbers of relayed synapses, and they may be excitatory and/or inhibitory in nature. Therefore vagus input would modulate the excitability of the M-cells.

Immunohistochemical demonstration of alpha1,4-N-acetylglucosaminyltransferase that forms GlcNAcalpha1,4Galbeta residues in human gastrointestinal mucosa

alpha1,4-N-acetylglucosaminyltransferase (alpha4GnT) is a glycosyltransferase that mediates transfer of GlcNAc to betaGal residues with alpha1,4-linkage, forming GlcNAcalpha1--> 4Galbeta-->R structures. In normal human tissues, glycoproteins having GlcNAcalpha1-->4Galbeta-->R structures at non-reducing terminals are exclusively limited to the mucins secreted from glandular mucous cells of gastric mucosa, Brunner's gland of duodenum, and accessory gland of pancreaticobiliary tract. Recently, we have isolated a cDNA encoding human alpha4GnT by expression cloning. Although alpha4GnT plays a key role in producing this unique glycan in vitro, the actual localization of alpha4GnT was not determined. In this study we examined the localization of alpha4GnT in various human tissues, including gastrointestinal mucosa, using a newly developed antibody against human alpha4GnT. The specificity of the antibody was confirmed by analyses of human gastric adenocarcinoma AGS cells transfected by alpha4GnT cDNA. Expression of alpha4GnT was largely associated with the Golgi region of mucous cells that produce the mucous glycoproteins having GlcNAcalpha1-->4Galbeta-->R, such as the glandular mucous cells of stomach and Brunner's gland. An immunoprecipitation experiment disclosed that two distinct mucin proteins, MUC5AC and MUC6 present in gastric mucin, carried the GlcNAcalpha1-->4Galbeta-->R structures. These results indicate that alpha4GnT is critical to form the mucous glycoproteins having GlcNAcalpha1-->4Galbeta-->R on MUC6 and MUC5AC in vivo.(J Histochem Cytochem 49:587-596, 2001)

[Study on endothelial dysfunction and platelet activation in elderly hypertensive patients complicated with cerebral infarction]

OBJECTIVE

The aim of this paper was to investigate endothelial dysfunction, platelet activation, and inflammation in elderly hypertensive patients and those complicated with cerebral infarction.

METHODS

Twenty-eight elderly hypertensive patients complicated with cerebral infarction(within 72 hours after onset of neurological symptoms), thirty-one Stage I-II elderly hypertensive patients and twenty-eight elderly healthy individuals were selected as subjects. Their plasma concentrations of von Willebrand factor(vWF), alpha granule membrane protein-140(GMP-140), and serum concentrations of C-reaction protein(CRP) were examined.

RESULTS

Elderly hypertensive patients complicated with cerebral infarction had significantly higher plasma vWF, GMP-140, and serum CRP than elderly hypertensive patients and elderly healthy individuals. Plasma vWF and GMP-140 were higher in elderly hypertensive patients than elderly healthy individuals, whereas serum CRP was increased slightly and there was no significant difference between elderly hypertensive patients and elderly healthy individuals.

CONCLUSION

This study suggests that elderly hypertensive patients complicated with cerebral infarction have obvious endothelial dysfunction, platelet activation, and inflammatory change. Stage I-II elderly hypertensive patients have obvious endothelial dysfunction and platelet activation as well.

Proliferation-associated expression of the MEN1 gene as revealed by in situ hybridization: possible role of the menin as a negative regulator of cell proliferation under DNA damage

The gene responsible for multiple endocrine neoplasia type 1 (MEN1) has recently been identified. Wide expression of the MEN1 gene in endocrine and non-endocrine organs examined by northern blotting has been reported, but the detailed cellular distribution of the MEN1 transcript in each tissue has not yet been examined in any species. In this report, expression of the MEN1 gene in adult human tissues was studied by in situ hybridization. The MEN1 transcript was widely observed in all tissues examined, and an enhanced expression in relation to cell proliferation was seen in some organs. Cell cycle arrest at the G1-S border reduced the MEN1 mRNA level to less than 50% of that in exponentially growing asynchronous cells. The expression increased as cells entered into S phase, indicating cell cycle-associated transcriptional regulation of the MEN1 gene. Increase or decrease of the amount of menin did not affect proliferation of CHO cells under normal conditions. However, when cells were exposed to the DNA-cross-linking agent, diepoxybutane, overexpression of wild-type menin inhibited DNA synthesis. This effect was not observed when cells were exposed to ultraviolet light. These results suggest that menin may negatively regulate cell cycle under certain DNA damage.

Hepta- and Octanitrocubanes

Four of the eight nitro groups of octanitrocubane 1 are introduced by functional group modification, three more by the astonishingly rapid, low-temperature N(2)O(4) nitration of sequentially formed polynitrocubyl anions, and the eighth and last by nitrosation of the heptanitrocubyl anion followed by ozonation.

Contrasting roles of mannan-specific monoclonal immunoglobulin M antibodies in the activation of classical and alternative pathways by Candida albicans

Polyclonal antimannan immunoglobulin G (IgG) activates the classical complement pathway and accelerates initiation of the alternative pathway by Canidida albicans. This dual role was assessed for two antimannan IgM monoclonal antibodies (MAbs). MAb B6.1 is specific for an epitope on the acid-labile portion of C. albicans phosphomannan; MAb B6 is specific for an epitope on the acid-stable region. Both MAbs were potent activators of the classical pathway but poor facilitators of alternative pathway initiation.

Mannan-specific immunoglobulin G antibodies in normal human serum accelerate binding of C3 to Candida albicans via the alternative complement pathway

Candida albicans activates the classical and alternative complement pathways, leading to deposition of opsonic complement fragments on the cell surface. Our previous studies found that antimannan immunoglobulin G (IgG) in normal human serum (NHS) allows C. albicans to initiate the classical pathway. The purpose of this study was to determine whether antimannan IgG also plays a role in initiation of the alternative pathway. Pooled NHS was rendered free of classical pathway activity by chelation of serum Ca2+ with EGTA alone or in combination with immunoaffinity removal of antimannan antibodies. Kinetic analysis revealed a 6-min lag in detection of C3 binding to C. albicans incubated in EGTA-chelated NHS, compared to a 12-min lag in NHS that was both EGTA chelated and mannan absorbed. The 12-min lag was shortened to 6 min by addition of affinity-purified antimannan IgG. The accelerating effect of antimannan IgG on alternative pathway initiation was dose dependent and was reproduced in a complement binding reaction consisting of six purified proteins of the alternative pathway. Both Fab and F(ab')2 fragments of antimannan IgG facilitated alternative pathway initiation in a manner similar to that observed with intact antibody. Immunofluorescence analysis showed that addition of antimannan IgG to EGTA-chelated and mannan-absorbed serum promoted an early deposition of C3 molecules on the yeast cells but had little or no effect on distribution of the cellular sites for C3 activation. Thus, antimannan IgG antibodies play an important regulatory role in interactions between the host complement system and C. albicans.

A case-control study of hepatitis B and C virus infection as risk factors for hepatocellular carcinoma in Henan, China

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common cancers in the world and is particularly prevalent in China. China is also a hyperendemic area for hepatitis B virus (HBV) infection. Although a strong association between HBV infection and HCC has been established previously, the role of hepatitis C virus (HCV) infection and the interaction between HBV and HCV in the development of HCC has not been adequately explored. The major objective of this study is to determine the relationship between HBV or HCV infection and HCC by use of case-control study in Henan, China.

METHOD

In all, 152 HCC patients and 115 control patients were collected from four hospitals in Henan, China between January 1994 and October 1995. The demographic characteristics of the two groups were comparable. In further analysis, a 1:1 pair-matched case-control study was performed. Of 152 HCC patients, 113 were randomly selected to be pair-matched by sex and age (+/-5 years) to controls with non-hepatic disease. All the cases and controls were interviewed during hospitalization by two specially trained interviewers using a standard questionnaire. All sera were tested for HBV and HCV markers. Odds ratios (OR) and 95% CI for HCC risk factors were calculated by logistic regression model controlling for possible confounding factors such as sex and age. The multivariate analysis was done on the basis of the univariate analysis.

RESULTS

The results of this study indicated that the prevalence of hepatitis B surface antigen (HBsAg) and antibody to HCV (anti-HCV) were much higher in HCC patients (63.2% and 11.2% respectively) than in the control patients (5.2%, 3.5%). The difference between two groups was significant (P < 0.05). Risk factor analysis revealed that both HBV and HCV infection were important factors for HCC in Henan, China and HBV appeared to have a key role in the development of HCC. Odds ratios of HBsAg and HBV infection were 28.82 (95% CI: 11.18-78.78) and 31.22 (95% CI: 13.86-72.15), respectively. Moreover, the risk of developing HCC increased significantly and showed an additive effect when both viral markers of HBV and HCV infection were considered (OR = 42.85). Results from the 1:1 pair-matched case-control study also showed that HBV infection was an important risk factor for HCC, which was consistent with the results from the group-matched case-control study.

CONCLUSION

This is the first reported case-control study of HCC in Henan, China. This study provides further evidence that chronic HBV infection is strongly associated with the development of HCC among this population. Our results have demonstrated that HCV and HBV infection are independent and probably additive risk factors for HCC.

Mannan-specific immunoglobulin G antibodies in normal human serum mediate classical pathway initiation of C3 binding to Candida albicans

Candida albicans activates both the classical and alternative complement pathways. Previous studies found that immunoglobulin G (IgG) in normal human serum (NHS) mediates classical pathway initiation. The goal of this study was to determine the role of candidal mannan-specific human IgG antibodies in complement activation. Mannan was purified from the yeast cells, and naturally occurring antimannan IgG was isolated from pooled NHS or plasma samples by immunoaffinity chromatography. Early activation and binding of C3, characteristics of classical pathway activity, were abolished in yeast- or mannan-absorbed serum but could be restored to absorbed serum with added purified antimannan IgG in a dose-dependent manner. Microscopically, the immunofluorescence pattern of initial C3 binding was diffuse over the entire cell surface for yeast cells incubated in NHS or in mannan-absorbed NHS supplemented with antimannan IgG but was asynchronous and focal for yeast cells incubated in EGTA-treated or mannan-absorbed NHS. The antimannan IgG level in serum samples from 21 donors varied from 17 to 570 microg/ml of serum compared to 220 microg in pooled NHS samples. The rate of initial C3 binding to yeast cells correlated with the level of antimannan IgG in sera from different individuals (r2 = 0.94) and could be accelerated in sera containing lower amounts of antimannan IgG with exogenous antimannan IgG. These observations identify antimannan IgG as the initiator of classical pathway C3 deposition on C. albicans. Given the variability in the levels of antimannan antibodies in sera from different individuals, the presence or absence of these antibodies may be an important determinant of host resistance to disseminated candidiasis.

Activation, binding, and processing of complement component 3 (C3) by Blastomyces dermatitidis

Complement plays a key role in phagocyte recognition and killing of Blastomyces dermatitidis, but little is known about how complement components interact with the yeast. We report the characteristics of activation, binding, and processing of C3 by B. dermatitidis. In pooled normal human serum (NHS), deposition of C3 on the yeast was detectable within 2 min, whereas in NHS containing MgEGTA, deposition was delayed by 6 min, indicating that the yeast activates C3 by both classical and alternative pathways. When both pathways were operative, maximal binding of 4.5 x 10(6) C3 molecules/cell was achieved in less than 30 min. In the absence of the classical pathway, yeast cells bound 80% of the maximum C3, indicating that the yeast intrinsically activates the alternative pathway. Delayed deposition of C3 in NHS-MgEGTA was similar to that in NHS preabsorbed by the yeast or by immobilized protein A/G to remove serum immunoglobulin. Purified immunoglobulin restored C3 binding to NHS preabsorbed by the yeast, suggesting that antibody in nonimmune serum initiates the classical pathway. beta-Glucan absorption of NHS abolished the classical pathway, suggesting that cell wall beta-glucan is a target of initiating antibodies. Hydroxylamine treatment of NHS-opsonized yeast cells showed that 76% of C3 was bound to yeast cells by ester linkage, supporting a role for hydroxyl groups on cell wall polysaccharides. Hydroxylamine-cleaved fragments were chiefly C3b and iC3b; 70% of hydroxylamine-sensitive C3b was converted to iC3b within 1 min of opsonization, and the ratio was stable over 1 h. Our data predict that C3b and iC3b on opsonized yeast cells direct binding to CR1 and CR3 receptors on human phagocytes, which, in turn, may influence the fate of this host-pathogen interaction.

A role for the disulfide bond spacer region of the Chlamydomonas reinhardtii coupling factor 1 gamma-subunit in redox regulation of ATP synthase

The gamma-subunit of chloroplast coupling factor 1 contains a disulfide bond which is involved in the redox regulation of the enzyme. In all the sequence plant gamma-subunits this disulfide bond is separated by a five amino acid spacer region. To investigate the regulatory significance of this region genetic transformation experiments were performed with Chlamydomonas reinhardtii. C. reinhardtii strain atpC1 (nitl-305, cw 15, mt-), which does not accumulate the CF1 gamma-subunit polypeptide, was independently transformed with two constructs, each bearing mutations within the disulfide bond spacer region between Cys198 and Cys204 of the gamma-subunit. Successful complementation was confirmed by phenotypic selection, Northern blot analysis, and reverse transcription polymerase chain reaction. Whereas wild-type thylakoid membrane particles catalyze in vitro, PMS-dependent photophosphorylation that is stimulated 2-fold by the addition of DTT, similar particles from each of the mutant strains exhibit rates of ATP synthesis that are independent of DTT. Consistent with these results, wild-type CF1 ATPase activity is stimulated by DTT which is in contrast to the ATPase activities of both the mutant strains which are independent of DTT addition. These results suggest a role of the gamma-subunit disulfide bond spacer region in the redox regulation of chloroplast ATP synthase.

The application of prostaglandin E1 indirect portal vein angiography and color Doppler ultrasound in patients with post-devascularization portal hypertension

The selection of proper treatment is based on identification of the causes of massive hemorrhage of gastrointestinal tract after pericardial devascularization. The combined use of prostaglandin E1 indirect portal vein angiography, DSA of celiac artery and color Doppler can provide detailed information about portal vein system, including the presence of embolism, spongioid changes and devascularization of left gastric vein and left gastric artery and the direction of blood flow. If these techniques failed to reveal the causes of digestive tract bleeding, the endoscopy may show lesions of gastric mucosa, which could be accountable for the bleeding.

Role of the Chlamydomonas reinhardtii coupling factor 1 gamma-subunit cysteine bridge in the regulation of ATP synthase

The gamma-subunit of coupling factor 1 (CF1) contains a cysteine bridge that is thought to be involved in the redox control of enzymatic activity. In order to test the regulatory significance of this disulfide bond, genetic transformation experiments with Chlamydomonas reinhardtii were performed. C. reinhardtii strain atpC1 (nit1-305, cw 15, mt-), which is null for the gamma-subunit, was transformed and complemented with gamma-subunit constructs containing amino acid substitutions localized to the cysteine bridge between Cys198 and Cys204. Successful complementation was confirmed by phenotypic selection, Northern blot analysis, reverse transcription polymerase chain reaction, and cDNA sequencing. CF1 ATPase activities of the soluble enzymes were measured in the presence and absence of dithiothreitol (DTT). Mutant CF1 enzymes showed no effect of DTT although increased activity was observed for the wild-type enzyme. In vitro, phenazine methosulfate-dependent photophosphorylation assays revealed that wild-type CF1 exhibits a 2-fold stimulation in the presence of 25 mM DTT, whereas each of the mutant enzymes has activities that are DTT-independent. Growth measurements indicated that despite the absence of a regulatory disulfide/dithiol, the mutant strains grew with the same kinetics as wild type. This study provides evidence to illustrate the involvement of the gamma-subunit in the redox regulation of ATP synthesis in vivo. This work is also the first demonstration in C. reinhardtii of stable nuclear transformation using mutated genes to complement a known defect.

[Dietary survey and biochemical study of blood and urine among Yi and Han nationality farmers in low prevalent district of hypertension]

This paper reports the dietary investigation (55 persons) and nutrient biochemical analysis of blood and urine (173 persons) among Yi and Han nationality farmers with low incidence of hypertension in Weinin, Guizhou. The results suggest that the three main nutrients as protein, fat and carbohydrate had no uniform relationship to the blood pressure, but high potassium and low sodium diet was intimately correlated to the low incidence of hypertension. The Na/K ratio of dietary intake and urine was more closely related to blood pressure. The relationship between calcium and blood pressure was quite complicated. The appropriate ratio of calcium and magnesium intake may be significant in the prevention and treatment of hypertension. It also indicates some intrinsic connection between lipid metabolism and blood pressure, while the degree of smoking is definitely correlated to blood pressure.

Study on the mechanism of interferon action (XI)--Effect of pppA2'p5'A on the level of cAMP and cGMP in macrophages

In this paper, the increase of cellular cAMP and cGMP levels in macrophages induced by ppA2'p5' A2'p5'A (briefly 2'-5'P3A3) is first reported. The optimal concentration of 2'-5' P3A3 for the elevation of cellular cGMP to the highest level is 10(-7)-10(-6) mol/L, while that for cAMP is 10(-7) mol/L. The time for cGMP to reach its peak value is 15 min and that for cAMP is 2 h, when the cells are treated with 2'-5' P3A3 at 10(-7) mol/L, which is the optimal concentration for developing biological effect of macrophages (phagocytosis). These results suggest that cGMP and cAMP may be related to, or may be the mediators for, 2'-5'P3A3 action.