Osteoprotegerin ligand is a cytokine that regulates osteoclast differentiation and activation

The ligand for osteoprotegerin has been identified, and it is a TNF-related cytokine that replaces the requirement for stromal cells, vitamin D3, and glucocorticoids in the coculture model of in vitro osteoclastogenesis. OPG ligand (OPGL) binds to a unique hematopoeitic progenitor cell that is committed to the osteoclast lineage and stimulates the rapid induction of genes that typify osteoclast development. OPGL directly activates isolated mature osteoclasts in vitro, and short-term administration into normal adult mice results in osteoclast activation associated with systemic hypercalcemia. These data suggest that OPGL is an osteoclast differentiation and activation factor. The effects of OPGL are blocked in vitro and in vivo by OPG, suggesting that OPGL and OPG are key extracellular regulators of osteoclast development.

Dissection of TNF receptor 1 effector functions: JNK activation is not linked to apoptosis while NF-kappaB activation prevents cell death

Through its type 1 receptor (TNFR1), the cytokine TNF elicits an unusually wide range of biological responses, including inflammation, tumor necrosis, cell proliferation, differentiation, and apoptosis. We investigated how TNFR1 activates different effector functions; the protein kinase JNK, transcription factor NF-kappaB, and apoptosis. We found that the three responses are mediated through separate pathways. Recruitment of the signal transducer FADD to the TNFR1 complex mediates apoptosis but not NF-kappaB or JNK activation. Two other signal transducers, RIP and TRAF2, mediate both JNK and NF-kappaB activation. These two responses, however, diverge downstream to TRAF2. Most importantly, JNK activation is not involved in induction of apoptosis, while activation of NF-kappaB protects against TNF-induced apoptosis.

TRADD-TRAF2 and TRADD-FADD interactions define two distinct TNF receptor 1 signal transduction pathways

Tumor necrosis factor (TNF) can induce apoptosis and activate NF-kappa B through signaling cascades emanating from TNF receptor 1 (TNFR1). TRADD is a TNFR1-associated signal transducer that is involved in activating both pathways. Here we show that TRADD directly interacts with TRAF2 and FADD, signal transducers that activate NF-kappa B and induce apoptosis, respectively. A TRAF2 mutant lacking its N-terminal RING finger domain is a dominant-negative inhibitor of TNF-mediated NF-kappa B activation, but does not affect TNF-induced apoptosis. Conversely, a FADD mutant lacking its N-terminal 79 amino acids is a dominant-negative inhibitor of TNF-induced apoptosis, but does not inhibit NF-kappa B activation. Thus, these two TNFR1-TRADD signaling cascades appear to bifurcate at TRADD.

The TNF receptor 1-associated protein TRADD signals cell death and NF-kappa B activation

Many diverse activities of tumor necrosis factor (TNF) are signaled through TNF receptor 1 (TNFR1). We have identified a novel 34 kDa protein, designated TRADD, that specifically interacts with an intracellular domain of TNFR1 known to be essential for mediating programmed cell death. Overexpression of TRADD leads to two major TNF-induced responses, apoptosis and activation of NF-kappa B. The C-terminal 118 amino acids of TRADD are sufficient to trigger both of these activities and likewise sufficient for interaction with the death domain of TNFR1. TRADD-mediated cell death can be suppressed by the crmA gene, which encodes a specific inhibitor of the interleukin-1 beta-converting enzyme. However, NF-kappa B activation by TRADD is not inhibited by crmA expression, demonstrating that the signaling pathways for TNF-induced cell death and NF-kappa B activation are distinct.

Tumor necrosis factor receptor family member RANK mediates osteoclast differentiation and activation induced by osteoprotegerin ligand

A receptor that mediates osteoprotegerin ligand (OPGL)-induced osteoclast differentiation and activation has been identified via genomic analysis of a primary osteoclast precursor cell cDNA library and is identical to the tumor necrosis factor receptor (TNFR) family member RANK. The RANK mRNA was highly expressed by isolated bone marrow-derived osteoclast progenitors and by mature osteoclasts in vivo. Recombinant OPGL binds specifically to RANK expressed by transfected cell lines and purified osteoclast progenitors. Transgenic mice expressing a soluble RANK-Fc fusion protein have severe osteopetrosis because of a reduction in osteoclasts, similar to OPG transgenic mice. Recombinant RANK-Fc binds with high affinity to OPGL in vitro and blocks osteoclast differentiation and activation in vitro and in vivo. Furthermore, polyclonal Ab against the RANK extracellular domain promotes osteoclastogenesis in bone marrow cultures suggesting that RANK activation mediates the effects of OPGL on the osteoclast pathway. These data indicate that OPGL-induced osteoclastogenesis is directly mediated through RANK on osteoclast precursor cells.

TNF-dependent recruitment of the protein kinase RIP to the TNF receptor-1 signaling complex

The death domain of tumor necrosis factor (TNF) receptor-1 (TNFR1) triggers distinct signaling pathways leading to apoptosis and NF-kappa B activation through its interaction with the death domain protein TRADD. Here, we show that TRADD interacts strongly with RIP, another death domain protein that was shown previously to associate with Fas antigen. We also show that RIP is a serine-threonine kinase that is recruited by TRADD to TNFR1 in a TNF-dependent process. Overexpression of the intact RIP protein induces both NF-kappa B activation and apoptosis. However, expression of the death domain of RIP Induces apoptosis, but potently inhibits NF-kappa B activation by TNF. These results suggest that distinct domains of RIP participate in the TNF signaling cascades leading to apoptosis and NF-kappa B activation.

RANK is the intrinsic hematopoietic cell surface receptor that controls osteoclastogenesis and regulation of bone mass and calcium metabolism

We have generated RANK (receptor activator of NF-kappaB) nullizygous mice to determine the molecular genetic interactions between osteoprotegerin, osteoprotegerin ligand, and RANK during bone resorption and remodeling processes. RANK(-/-) mice lack osteoclasts and have a profound defect in bone resorption and remodeling and in the development of the cartilaginous growth plates of endochondral bone. The osteopetrosis observed in these mice can be reversed by transplantation of bone marrow from rag1(-/-) (recombinase activating gene 1) mice, indicating that RANK(-/-) mice have an intrinsic defect in osteoclast function. Calciotropic hormones and proresorptive cytokines that are known to induce bone resorption in mice and human were administered to RANK(-/-) mice without inducing hypercalcemia, although tumor necrosis factor alpha treatment leads to the rare appearance of osteoclast-like cells near the site of injection. Osteoclastogenesis can be initiated in RANK(-/-) mice by transfer of the RANK cDNA back into hematopoietic precursors, suggesting a means to critically evaluate RANK structural features required for bone resorption. Together these data indicate that RANK is the intrinsic cell surface determinant that mediates osteoprotegerin ligand effects on bone resorption and remodeling as well as the physiological and pathological effects of calciotropic hormones and proresorptive cytokines.

The ligand for osteoprotegerin (OPGL) directly activates mature osteoclasts

Osteoprotegerin (OPG) and OPG-ligand (OPGL) potently inhibit and stimulate, respectively, osteoclast differentiation (Simonet, W.S., D.L. Lacey, C.R. Dunstan, M. Kelley, M.-S. Chang, R. Luethy, H.Q. Nguyen, S. Wooden, L. Bennett, T. Boone, et al. 1997. Cell. 89:309-319; Lacey, D.L., E. Timms, H.-L. Tan, M.J. Kelley, C.R. Dunstan, T. Burgess, R. Elliott, A. Colombero, G. Elliott, S. Scully, et al. 1998. Cell. 93: 165-176), but their effects on mature osteoclasts are not well understood. Using primary cultures of rat osteoclasts on bone slices, we find that OPGL causes approximately sevenfold increase in total bone surface erosion. By scanning electron microscopy, OPGL-treated osteoclasts generate more clusters of lacunae on bone suggesting that multiple, spatially associated cycles of resorption have occurred. However, the size of individual resorption events are unchanged by OPGL treatment. Mechanistically, OPGL binds specifically to mature OCs and rapidly (within 30 min) induces actin ring formation; a marked cytoskeletal rearrangement that necessarily precedes bone resorption. Furthermore, we show that antibodies raised against the OPGL receptor, RANK, also induce actin ring formation. OPGL-treated mice exhibit increases in blood ionized Ca++ within 1 h after injections, consistent with immediate OC activation in vivo. Finally, we find that OPG blocks OPGL's effects on both actin ring formation and bone resorption. Together, these findings indicate that, in addition to their effects on OC precursors, OPGL and OPG have profound and direct effects on mature OCs and indicate that the OC receptor, RANK, mediates OPGL's effects.

APRIL and TALL-I and receptors BCMA and TACI: system for regulating humoral immunity

We report that the tumor neurosis factor homolog APRIL (a proliferation-inducing ligand) stimulates in vitro proliferation of primary B and T cells and increases spleen weight due to accumulation of B cells in vivo. APRIL functions via binding to BCMA (B cell maturation antigen) and TACI (transmembrane activator and CAML-interactor) and competes with TALL-I (also called BLyS or BAFF) for receptor binding. Soluble BCMA and TACI specifically prevent binding of APRIL and block APRIL-stimulated proliferation of primary B cells. BCMA-Fc also inhibits production of antibodies against keyhole limpet hemocyanin and Pneumovax in mice, indicating that APRIL and/or TALL-I signaling via BCMA and/or TACI are required for generation of humoral immunity. Thus, APRIL-TALL-I and BCMA-TACI form a two ligands-two receptors pathway involved in stimulation of B and T cell function.

Severe B cell hyperplasia and autoimmune disease in TALL-1 transgenic mice

TALL-1/Blys/BAFF is a member of the tumor necrosis factor (TNF) ligand superfamily that is functionally involved in B cell proliferation. Here, we describe B cell hyperplasia and autoimmune lupus-like changes in transgenic mice expressing TALL-1 under the control of a beta-actin promoter. The TALL-1 transgenic mice showed severe enlargement of spleen, lymph nodes, and Peyer's patches because of an increased number of B220+ cells. The transgenic mice also had hypergammaglobulinemia contributed by elevations of serum IgM, IgG, IgA, and IgE. In addition, a phenotype similar to autoimmune lupus-like disease was also seen in TALL-1 transgenic mice, characterized by the presence of autoantibodies to nuclear antigens and immune complex deposits in the kidney. Prolonged survival and hyperactivity of transgenic B cells may contribute to the autoimmune lupus-like phenotype in these animals. Our studies further confirm TALL-1 as a stimulator of B cells that affect Ig production. Thus, TALL-1 may be a primary mediator in B cell-associated autoimmune diseases.

Modulation of T-cell-mediated immunity in tumor and graft-versus-host disease models through the LIGHT co-stimulatory pathway

LIGHT was recently described as a member of the tumor necrosis factor (TNF) 'superfamily'. We have isolated a mouse homolog of human LIGHT and investigated its immunoregulatory functions in vitro and in vivo. LIGHT has potent, CD28-independent co-stimulatory activity leading to T-cell growth and secretion of gamma interferon and granulocyte-macrophage colony-stimulating factor. Gene transfer of LIGHT induced an antigen-specific cytolytic T-cell response and therapeutic immunity against established mouse P815 tumor. In contrast, blockade of LIGHT by administration of soluble receptor or antibody led to decreased cell-mediated immunity and ameliorated graft-versus-host disease. Our studies identify a previously unknown T-cell co-stimulatory pathway as a potential therapeutic target.

Hepatitis B virus infection in children and adolescents in a hyperendemic area: 15 years after mass hepatitis B vaccination

BACKGROUND

Hepatitis B virus (HBV) infection is hyperendemic in Taiwan. Before universal HBV immunization was started in Taiwan in 1984, the carrier rate for hepatitis B surface antigen (HBsAg) was 15% to 20% in the general population.

OBJECTIVE

To quantify the population impact of a mass vaccination program for HBV 15 years after its implementation.

DESIGN

Descriptive analysis of serologic markers of HBV in healthy children and adolescents.

SETTING

Chung-Cheng District, Taipei City, Taiwan, in 1999.

PARTICIPANTS

1357 persons younger than 15 years of age, who were born after the implementation of universal HBV vaccination, and 559 persons 15 to 20 years of age, who were born before the program began.

MEASUREMENTS

Repeated serologic surveys similar to those done before and 5 and 10 years after the national vaccination program was implemented. All participants were tested for serum HBsAg, its antibody (anti-HBs), and hepatitis B core antibody (anti-HBc).

RESULTS

During the 15 years since the vaccination program was implemented, the prevalence of HBsAg among persons younger than 15 years of age decreased from 9.8% in 1984 to 0.7% in 1999; among persons 15 to 20 years of age, the 1999 prevalence of HBsAg was 7% (P < 0.001). Hepatitis B core antibody seropositivity, which represents HBV infection, was found in 2.9% of persons younger than 15 years of age and in 20.6% of persons 15 to 20 years of age (P < 0.001); in the same age groups, the rate of anti-HBs seropositivity was 75.8% and 70.7%, respectively (P = 0.02).

CONCLUSIONS

Universal vaccination significantly decreased the HBV carrier rate and infection rate among children and adolescents born since the program began. By decreasing the carrier pool, continuation of the national HBV immunization program should prevent HBV infection in the children of Taiwan, and, subsequently, adults as well.

Changes of hepatitis B surface antigen variants in carrier children before and after universal vaccination in Taiwan

Mutants of a determinant of hepatitis B surface antigen (HBsAg) identified in vaccinated children pose a potential threat to long-term success of vaccination programs. We examined the mutants of a determinant (residues 110-160) of HBsAg in hepatitis B virus (HBV) DNA-positive children identified during previous serosurveys in Taipei undertaken just before (1984), 5 years after (1989), and 10 years after (1994) universal vaccination began. In HBV DNA-positive children from 3 surveys, the prevalence of a determinant mutants increased from 8 of 103 (7.8%) in 1984 to 10 of 51(19.6%) in 1989 and 9 of 32 (28.1%) in 1994 and was higher in those fully-vaccinated than unvaccinated (12/33 vs. 15/153, P =. 0003). Most amino acid changes of the variants clustered in residues 125-129 and 140-149. In all 27 children with detectable mutants, the mean age of those vaccinated was younger than those unvaccinated (4. 8 +/- 3.8 vs. 7.9 +/- 2.3 yrs, P <.05); and mutations occurred in a region with greatest local hydrophilicity (residues 140-149) more frequently in those vaccinated than in those unvaccinated (10/12 vs. 6/15, P =.0253). More mutated residues and more mutations at neutralizing epitopes, such as N146, C147, T148, and C149, were found in the 1994 survey. Vaccinated children may contract variant infections through vertical or horizontal transmission. Universal vaccination has accelerated an accumulation of HBsAg a determinant mutants with amino acid changes critical for immune escape in vaccinated children who became carriers, suggesting that new vaccination strategies should be considered.

Seroepidemiology of hepatitis B virus infection in children: Ten years of mass vaccination in Taiwan

OBJECTIVE

To study the seroepidemiology of hepatitis B virus (HBV) infection in children 10 years after a mass hepatitis B vaccination program was begun in Taiwan.

DESIGN

Cross-sectional seroprevalence survey.

SETTING

Cheng-Chung/Chung-Cheng District, Taipei, Taiwan, 1994.

SUBJECTS AND METHODS

Serum samples from 1515 healthy children younger than 12 years were tested for HBV markers. The results were compared with a baseline seroepidemiologic study conducted just before the vaccination program was launched in 1984 and with a subsequent study in 1989 in the same area.

MAIN RESULTS

Eighty-seven percent of the children had received at least 3 doses of HBV vaccine. The overall prevalence rate of hepatitis B surface antigenemia decreased from 9.8% in 1984 to 1.3% in 1994. A statistically significant decrease was observed in every age group from 1 to 10 years. The overall prevalence rate of hepatitis B core antibody was 26% in 1984, 15% in 1989, and 4.0% in 1994. This suggests that the risk of horizontal HBV infection has decreased over time, not only because of the protective effect of the vaccine but also because the infection source has diminished. A high prevalence rate of hepatitis B surface antibody (79%) was noted in 1994 as anticipated.

CONCLUSIONS

The Taiwanese mass vaccination program has protected most children younger than 10 years from becoming carriers, reducing both perinatal and horizontal HBV transmission. Mass HBV vaccination has proved to be a successful method to control HBV infection in this hyperendemic area.

ATAR, a novel tumor necrosis factor receptor family member, signals through TRAF2 and TRAF5

Members of tumor necrosis factor receptor (TNFR) family signal largely through interactions with death domain proteins and TRAF proteins. Here we report the identification of a novel TNFR family member ATAR. Human and mouse ATAR contain 283 and 276 amino acids, respectively, making them the shortest known members of the TNFR superfamily. The receptor is expressed mainly in spleen, thymus, bone marrow, lung, and small intestine. The intracellular domains of human and mouse ATAR share only 25% identity, yet both interact with TRAF5 and TRAF2. This TRAF interaction domain resides at the C-terminal 20 amino acids. Like most other TRAF-interacting receptors, overexpression of ATAR activates the transcription factor NF-kappaB. Co-expression of ATAR with TRAF5, but not TRAF2, results in synergistic activation of NF-kappaB, suggesting potentially different roles for TRAF2 and TRAF5 in post-receptor signaling.

Baseline seroepidemiology of hepatitis B virus infection in children in Taipei, 1984: a study just before mass hepatitis B vaccination program in Taiwan

Hepatitis B virus (HBV) markers were studied by radioimmunoassays in serum samples of 1,200 (647 male, 553 female) apparently healthy children under 15 years of age in Taipei between June and October 1984. The prevalence rate of hepatitis B surface antigen (HBsAg) was 5.1% in infancy, increased to 10.7% between 1 and 2 years of age, and then remained constant at about 10% thereafter. The prevalence rate of surface antibody (anti-HBs), core antibody (anti-HBc), and seropositivity (at least one marker of hepatitis B detectable) were 39.0, 30.5, and 52.5%, respectively, in infancy, then decreased to 10.7, 14.3, and 17.9%, respectively, between 1 and 2 years of age. Thereafter, the antibody prevalence increased in parallel with age. By the age of 13-14 years, nearly half of the children were infected by HBV. The results suggested that in our children, most HBsAg carriers resulted from infections before 3 years of age, and HBV infections after 3 years of age infrequently resulted in a carrier state. One hundred (83.3%) of the 120 HBsAg-positive children had hepatitis B e antigen (HBeAg), indicating high prevalence in young asymptomatic HBsAg carriers. The prevalence rate of HBeAg tended to decrease with age and a reversed trend was observed with anti-HBe. Our study, just before our government extends mass hepatitis B vaccination program from newborns to children, provides background seroepidemiologic data of HBV infections in the healthy children in Taiwan.

Ligands of macrophage scavenger receptor induce cytokine expression via differential modulation of protein kinase signaling pathways

Our previous works demonstrated that ligands of macrophage scavenger receptor (MSR) induce protein kinases (PKs) including protein-tyrosine kinase (PTK) and up-regulate urokinase-type plasminogen activator expression (Hsu, H. Y., Hajjar, D. P., Khan, K. M., and Falcone, D. J. (1998) J. Biol. Chem. 273, 1240--1246). To continue to investigate MSR ligand-mediated signal transductions, we focus on ligands, oxidized low density lipoprotein (OxLDL), and fucoidan induction of the cytokines tumor necrosis factor-alpha (TNF) and interleukin 1 beta (IL-1). In brief, in murine macrophages J774A.1, OxLDL and fucoidan up-regulate TNF production; additionally, fucoidan but not OxLDL induces IL-1 secretion, prointerleukin 1 (proIL-1, precursor of IL-1) protein, and proIL-1 message. Simultaneously, fucoidan stimulates activity of interleukin 1-converting enzyme. We further investigate the molecular mechanism by which ligand binding-induced PK-mediated mitogen-activated protein kinase (MAPK) in regulation of expression of proIL-1 and IL-1. Specifically, fucoidan stimulates activity of p21-activated kinase (PAK) and of the MAPKs extracellular signal-regulated kinase (ERK), c-Jun NH(2)-terminal kinase (JNK), and p38. Combined with PK inhibitors and genetic mutants of Rac1 and JNK in PK activity assays, Western blotting analyses, and IL-1 enzyme-linked immunosorbent assay, the role of individual PKs in the regulation of proIL-1/IL-1 was extensively dissected. Moreover, tyrosine phosphorylation of pp60Src as well as association between pp60Src and Hsp90 play important roles in fucoidan-induced proIL-1 expression. We are the first to establish two fucoidan-mediated signaling pathways: PTK(Src)/Rac1/PAK/JNK and PTK(Src)/Rac1/PAK/p38, but not PTK/phospholipase C-gamma 1/PKC/MEK1/ERK, playing critical roles in proIL-1/IL-1 regulation. Our current results indicate and suggest a model for MSR ligands differentially modulating specific PK signal transduction pathways, which regulate atherogenesis-related inflammatory cytokines TNF and IL-1.

Two antiplatelet agents from Magnolia officinalis

Magnolol and honokiol are two position isomers isolated from the bark of Magnolia officinalis. Both inhibited the aggregation and ATP release of rabbit platelet-rich plasma induced by collagen and arachidonic acid without affecting that induced by ADP, PAF or thrombin. Aggregation of washed platelets was more markedly inhibited than that of platelet-rich plasma, while the aggregation of whole blood was least affected by both inhibitors. Thromboxane B2 formation caused by collagen, arachidonic acid or thrombin was in each case inhibited by magnolol and honokiol. The rise of intracellular calcium caused by arachidonic acid or collagen was also suppressed by both agents. Collagen-induced intracellular calcium increase in the presence of indomethacin was suppressed by magnolol. It is concluded that the antiplatelet effect of magnolol and honokiol is due to an inhibitory effect on thromboxane formation and also an inhibition of intracellular calcium mobilization.

Surface gene mutants of hepatitis B virus in infants who develop acute or chronic infections despite immunoprophylaxis

Serum hepatitis B virus (HBV) DNA from 4 infants with fulminant hepatitis B, 3 infants with acute self-limited hepatitis B, and 15 infants with chronic HBV infection were amplified by polymerase chain reaction followed by direct sequencing of the region of HBV genome encoding the major antigenic epitopes of hepatitis B surface antigen (HBsAg). All infants were born to carrier mothers and administered immunoprophylaxis from birth. Serum HBV DNA from 13 carrier children born to carrier mothers who did not receive immunoprophylaxis and had comparable length of infection were studied as controls. An S mutant (residue 126, Thr to Ala) initially found in an infant with fulminant hepatitis was replaced by another S mutant (residue 145, Gly to Arg) 4 days later. In a girl with chronic hepatitis B, Ala-126 variant and Arg-145 variant were found at 17 and 25 months of age, respectively. The Arg-145 variant persisted for 8 years in an asymptomatic male carrier and for 1 year in an infant with chronic hepatitis B. The Ala-126 variant persisted for 11 years in one child who had an early loss of hepatitis B e antigen. In the majority of the infants' mothers, corresponding mutations in HBsAg were not detected in serum by direct sequencing. The S mutants detected in three carrier infants were not found in their mothers' serum after cloning and sequencing of 10 DNA clones from each maternal sample. None of the 13 control patients had detectable S mutants. These results suggest that S variants emerge or are selected under the immune pressure generated by the host or by administration of hepatitis B immune globulin and hepatitis B vaccination. An S mutant (residue 129, Gln to Arg) found in one mother-infant pair suggested a direct maternal-infant transmission, resulting in immunoprophylaxis failure. None of the family members of children infected with Arg-145 variant had the same variant infection, implying this variant's low transmissability.

Hepatitis B vaccination and hepatocellular carcinoma rates in boys and girls

CONTEXT

Hepatocellular carcinoma (HCC) has a male predominance and is closely related to hepatitis B virus (HBV) infection. Hepatitis B virus vaccination was launched in 1984 in Taiwan for neonates of mothers carrying hepatitis B e antigen, resulting in a decreased incidence of HCC in children. The effect on boys vs girls is not known.

OBJECTIVE

To evaluate the association between a HBV vaccination program with incidence of childhood HCC by sex.

DESIGN AND SETTING

Analysis of data collected from Taiwan's National Cancer Registry System and the Taiwan Childhood Hepatoma Study Group between 1981 and 1996.

PARTICIPANTS

Children aged 6 to 14 years who were diagnosed as having HCC (201 boys and 70 girls).

MAIN OUTCOME MEASURE

Incidence of HCC in boys and girls before and after implementation of the vaccination program.

RESULTS

The boy-girl incidence ratio decreased steadily from 4.5 in 1981-1984 (before the program's introduction) to 1.9 in 1990-1996 (6-12 years after the vaccination program was launched). The incidence of HCC in boys born after 1984 was significantly reduced in comparison with those born before 1978 (relative risk [RR], 0.72; P =.002). No significant decrease in HCC incidence was observed in girls born in the same periods (RR, 0.77; P =.20). The incidence of HCC in boys remained stable with increasing age, while an increase of HCC incidence with age in girls was observed. These age and sex effects remained the same regardless of birth before or after the vaccination program.

CONCLUSION

Our results suggest that boys may benefit more from HBV vaccination than girls in the prevention of HCC.

Effects of oleanolic acid and ursolic acid on inhibiting tumor growth and enhancing the recovery of hematopoietic system postirradiation in mice

Two triterpene acids, oleanolic acid (OA) and ursolic acid (UA) were examined for their ability to inhibit the tumor growth and modify hematopoiesis after irradiation in three experimental systems: (a) in vivo anti-tumor activity of implanted tumor by ascitic cells was found to be augmented by addition of OA and UA at a high concentration and inhibited in a dose-dependent manner; (b) in the sublethal whole-body irradiated mice treated with the drugs in the 30 min preirradiation period, enhanced effects of OA and UA on peripheral leukocytes were observed by a different significance, and (c) when these chemicals were administered i.p. to mice 30 min before 4 Gy irradiation, both OA and UA enhanced the postirradiation responses of splenic blastogenesis by PHA. UA was a more potent tumorigenic inhibitor than OA. Combining with the gamma-irradiation, however, there was no significant synergetic effect on their anti-tumor activity. The beneficial effects of OA and UA on hematopoiesis and immunocompetence under this study, suggested they might partially play a role in anti-cancer and, furthermore, with the ability to decrease undesirable radiation damage to the hematopoietic tissue after radiotherapy.

A prediction model for type 2 diabetes risk among Chinese people

AIMS/HYPOTHESIS

A range of prediction rules for the onset of type 2 diabetes have been proposed. However, most studies have been conducted in white groups and it is not clear whether these models apply to Asian populations. The purpose of this study was to construct a simple points model for predicting incident diabetes among Chinese people.

METHODS

We estimated the 10 year risk of diabetes in a cohort study of middle-aged and elderly participants who were free from diabetes at baseline. Cox regression coefficients were used to construct the simple points model and the discriminatory ability of the resulting prediction rule was determined using AUC and net reclassification improvement and integrated discrimination improvement statistics. Fivefold random splitting was used to test the internal validity and obtain bootstrap estimates of the AUC.

RESULTS

Of the 2,960 participants without diabetes at the baseline examination, 548 developed type 2 diabetes during a median 10 year follow-up period. Age (four points), elevated fasting glucose (11 points), body mass index (eight points), triacylglycerol (five points), white blood cell count (four points) and a higher HDL-cholesterol (negative four points) were found to strongly predict diabetes incidence in a multivariate model. The estimated AUC for the model was 0.702 (95% CI 0.676-0.727). This model performed better than existing prediction models developed in other populations, including the Prospective Cardiovascular Münster, Cambridge, San Antonia and Framingham models for diabetes risk.

CONCLUSIONS/INTERPRETATION

We have constructed a model for predicting the 10 year incidence of diabetes in Chinese people that could be useful for identifying individuals at high risk of diabetes in the Chinese population.

Absence of infection in breast-fed infants born to hepatitis C virus-infected mothers

The role of breast-feeding in perinatal transmission of hepatitis C virus (HCV) was explored in 15 HCV-infected mothers and their infants. The 15 carrier mothers had anti-HCV titers ranging from 1:80 to 1:40,000 and also had HCV-ribonucleic acid with concentrations ranging from 10(4) to 2.5 x 10(8) copies/ml. Both anti-HCV antibody and HCV-ribonucleic acid were present in colostral samples in much lower levels, but none of the 11 breast-fed infants had evidence of HCV infection for up to 1 year of age. Thus breast-feeding seems safe for these infants.

Possible role of high-titer maternal viremia in perinatal transmission of hepatitis C virus

To study perinatal transmission of hepatitis C virus (HCV), 15 anti-HCV-positive carrier mothers without human immunodeficiency virus coinfection were recruited. At delivery, maternal blood was taken and anti-HCV titer was determined and HCV RNA measured in each serum sample by reverse transcription polymerase chain reaction (PCR). A competitive PCR was used in selected samples to quantitate HCV concentration. The 15 neonates were followed regularly for 1 year and their sera were also assayed for anti-HCV and for HCV RNA by reverse transcription PCR. All the mothers were positive for HCV RNA. Only one normal spontaneously delivered neonate of a mother with extremely high titer of anti-HCV (1:20,000) and HCV concentration (10(10) copies/mL) had both anti-HCV and HCV RNA in serum for up to 6 months of age. In contrast, none of the remaining 14 neonates born to mothers with low- to high-titer anti-HCV (1:4-1:1000) and moderate amounts of HCV RNA (10(5)-10(6) copies/mL) contracted HCV infection. The results imply that high-titer maternal viremia and normal spontaneous delivery may allow more HCV to infect the neonate intrapartum, therefore establishing perinatal transmission.