Endothelium-dependent vasorelaxant and antiproliferative effects of apigenin

This study was designed to determine whether the relaxant effect of apigenin was endothelium dependent and to examine the possible antiproliferative effect of apigenin. Apigenin relaxed the phenylephrine-precontracted endothelium-intact aortic rings with IC(50) value of 3.7+/-0.5 microM and removal of a functional endothelium significantly attenuated this relaxation (IC(50)=8.2+/-0.9 microM). However, apigenin did not affect the 0.1 microM phorbol 12,13-dibutyrate-induced contraction (IC(50)=34.6+/-1.2 microM) within the concentration range that relaxed the phenylephrine-contracted arteries, suggesting that apigenin did not influence protein kinase C-mediated contractile mechanisms in rat aorta. Pretreatment of apigenin significantly potentiated the relaxant effect of acetylcholine on phenylephrine-induced contraction. Pretreatment with N(G)-nitro-L-arginine methyl ester (L-NAME) or methylene blue reduced the relaxant effect of apigenin. Apigenin (10 microM) increased the guanosine 3',5'-cyclic monophosphate (cGMP) content of endothelium-intact tissues. Pretreatment with L-NAME (100 microM) or removal of endothelium significantly suppressed the effect of apigenin on cGMP production. In addition, apigenin significantly inhibited [3H]thymidine incorporation into DNA of primary cultured rat aortic smooth muscle cell in a dose-dependent manner. These findings suggest that besides influx and release of Ca(2+), nitric oxide (NO) and cGMP may account for the apigenin-induced endothelium-dependent relaxation and hypotensive activity. Both vasorelaxant and antiproliferative activities may contribute to a benefit of apigenin in the vascular system.

Late forming supernumerary tooth in the premaxilla: a case report

A case of late forming supernumerary tooth in the premaxilla is presented in this report. The patient has been followed-up radiographically from the age of 9 years but the supernumerary tooth could only be detected radiographically when the patient was 11 years old. This emphasises the importance of thorough clinical and radiographic examination of the developing dentition in children.

Differential inhibitory effects of sophoricoside analogs on bioactivity of several cytokines

Effects of sophoricoside and its analogs on proinflammatory cytokines have been investigated. Sophoricoside, genistein and orobol exhibited inhibitory effects on IL-5, IL-3, GM-CSF and IL-6 bioactivities. Genistin showed inhibitory effects on IL-5 and IL-3 bioactivities, but did not inhibit GM-CSF and IL-6 bioactivities. None of the sophoricoside analogs showed inhibitory effects on both IL-1beta and TNF-alpha bioactivities. Among the compounds, sophoricoside exhibited the highest inhibitory effects on IL-5, IL-3 and IL-6 bioactivities with IC50 values of 1.9 microM, 6.9 microM and 6.0 microM, respectively and orobol did show on GM-CSF bioactivity with an IC50 value of 18.0 microM. The result would provide an additional mechanism by which the compounds exert immunosuppressive and anti-inflammatory effects.

Antithrombotic and antiplatelet activities of 2-chloro-3-[4-(ethylcarboxy)-phenyl]-amino-1,4-naphthoquinone (NQ12), a newly synthesized 1,4-naphthoquinone derivative

The possibility of NQ12 (2-chloro-3-[4-(ethylcarboxy)-phenyl]-amino-1,4-naphthoquinone) as a novel antithrombotic agent and its mode of action were investigated. The effects of NQ12 on platelet aggregation in human platelet-rich plasma in vitro, in rats ex vivo, and on murine pulmonary thrombosis in vivo, as well as the mode of antithrombotic action were examined. NQ12 potently inhibited ADP-, collagen-, epinephrine-, and calcium ionophore-induced human platelet aggregations in vitro concentration-dependently. NQ12 significantly inhibited rat platelet aggregation in an ex vivo study. NQ12 prevented murine pulmonary thrombosis in a dose-dependent manner. However, NQ12 did not affect coagulation parameters such as activated partial thromboplastin time, prothrombin time, and thrombin time. NQ12 inhibited fibrinogen binding to the platelet surface GPIIb/IIIa receptor, but failed to inhibit binding to the purified GPIIb/IIIa receptor. Thromboxane B(2) formation caused by thrombin or collagen was inhibited significantly by NQ12. The phosphoinositide breakdown induced by thrombin or collagen was inhibited concentration-dependently by NQ12. These results suggest that NQ12 may be a promising antithrombotic agent, and its antithrombotic activity may be due to antiplatelet aggregation activity, which may result from the inhibition of phosphoinositide breakdown and thromboxane A(2) formation.

Impact response of the intervertebral disc in a finite-element model

STUDY DESIGN

A three-dimensional nonlinear poroelastic finite-element model of a vertebra disc was used to analyze the biomechanical effects of impact loading on the spinal segment.

OBJECTIVES

To predict changes in biomechanical parameters such as intradiscal pressure, dynamic stiffness, stresses in the endplate region, and the shock-absorbing mechanism of the spine under different impact duration/loading rates, and to investigate the relation between the rate of loading and the fracture potential of the vertebral body.

SUMMARY OF BACKGROUND DATA

It is not practical to discern the role of impact duration using experimental protocols. Analytical studies are better suited to this purpose. However, previous poroelastic finite-element models of the motion segments have dealt mostly with creep phenomena.

METHODS

A three-dimensional, L3-L4 motion-segment, finite-element model was modified to incorporate the poroelastic properties of the disc, endplate, and cancellous core, and thus simulate the shock-absorbing phenomena. The results were analyzed under variable impact durations for a constant maximum compressive impact load of 3 kN.

RESULTS

For a shorter impact duration and a given F(max), relatively high cancellous core pressure was generated as compared with a case of long impact duration, although the amount of impulse was increased. In contrast, relatively constant pore pressures were generated in the nucleus regardless of the impact duration. The changes in spinal segment stiffness as a function of impact duration indicated that for a shorter duration of impact, high dynamic stiffness increases the stability of the spinal segment against the impact load. However, the corresponding increase in stresses within the vertebral body and endplate may produce fractures.

CONCLUSIONS

The finite-element technique was used to address the role of impact duration in producing trauma to the spinal motion segment. Within the limitations of the model, the results suggest that fractures are likely to occur under shorter impact duration conditions. Depending on the strength of the region, a fracture may be initiated in the endplate region or the posterior wall of the cortical shell. The nucleus pressure is independent of the impact duration and depends only on the magnitude of the impact force.

Distinct requirements for IFNs and STAT1 in NK cell function

NK cell functions were examined in mice with a targeted mutation of the STAT1 gene, an essential mediator of IFN signaling. Mice deficient in STAT1 displayed impaired basal NK cytolytic activity in vitro and were unable to reject transplanted tumors in vivo, despite the presence of normal numbers of NK cells. IL-12 enhanced NK-mediated cytolysis, but poly(I:C) did not, and a similar phenotype occurred in mice lacking IFNalpha receptors. Molecules involved in activation and lytic function of NK cells (granzyme A, granzyme B, perforin, DAP10, and DAP12) were expressed at comparable levels in both wild-type and STAT1(-/-) mice, and serine esterase activity necessary for CTL function was normal, showing that the lytic machinery was intact. NK cells with normal cytolytic activity could be derived from STAT1(-/-) bone marrow progenitors in response to IL-15 in vitro, and enhanced NK lytic activity and normal levels of IFN-gamma were produced in response to IL-12 treatment in vivo. Despite these normal responses to cytokines, STAT1(-/-) mice could not reject the NK-sensitive tumor RMA-S, even following IL-12 treatment in vivo. Whereas in vitro NK cytolysis was also reduced in mice lacking both type I and type II IFN receptors, these mice resisted tumor challenge. These results demonstrate that both IFN-alpha and IFN-gamma are required to maintain NK cell function and define a STAT1-dependent but partially IFN-independent pathway required for NK-mediated antitumor activity.

Possible mode of antiviral activity of acidic protein bound polysaccharide isolated from Ganoderma lucidum on herpes simplex viruses

Two protein bound polysaccharides, a neutral protein bound polysaccharide (NPBP) and an acidic protein bound polysaccharide (APBP), were isolated from water soluble substances of Ganoderma lucidum by EtOH precipitation and DEAE-cellulose column chromatography. Their antiviral activities against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) were then investigated by plaque reduction assay. APBP exhibited more potent HSV-1 and HSV-2 antiviral activity than NPBP with 50% effective concentration (EC(50)) of 300-520 microg/ml. In order to examine the possible mode of the antiviral activity of APBP its virucidal effect, antiviral activity in preincubation, attachment and penetration assay were tested with HSV-1 and HSV-2. APBP was found to have a direct virucidal effect on HSV-1 and HSV-2. APBP did not induce IFN or IFN-like materials in vitro and is not expected to induce a change from a normal state to an antiviral state. APBP in concentrations of 100 and 90 microg/ml inhibited up to 50% of the attachment of HSV-1 and HSV-2 to Vero cells and was also found to prevent penetration of both types of HSV into Vero cells. These results show that the antiherpetic activity of APBP seems to be related to its binding with HSV-specific glycoproteins responsible for the attachment and penetration, and APBP impedes the complex interactions of viruses with cell plasma membranes.

Dynamical self-affinity of damage spreading in surface growth models

The dynamical anisotropic scaling properties of the surface growth models are restudied by use of the damage spreading concept. For that the vertical damage spreading distance d( perpendicular) of a damaged column as well as the lateral damage spreading distance d(||) is introduced. The scaling Ansatze for &dmacr;( perpendicular)(d(||),t), D(||) identical with<d(||)> and D( perpendicular) identical with<&dmacr;( perpendicular)> are suggested. The critical property of the probability distribution P(d(||),t) for the survived damages is also suggested. The suggested scaling relations are tested by simulating various growth models with substrate dimension d=1. From these results it can be concluded that the critical property or dynamical self-affinity of a surface growth model can also be determined by investigating the damage spreading.

Effects of protease inhibitors and antioxidants on In vitro survival of porcine primordial germ cells

One of the problems associated with in vitro culture of primordial germ cells (PGCs) is the large loss of cells during the initial period of culture. This study characterized the initial loss and determined the effectiveness of two classes of apoptosis inhibitors, protease inhibitors, and antioxidants on the ability of porcine PGCs to survive in culture. Results from electron microscopic analysis and in situ DNA fragmentation assay indicated that porcine PGCs rapidly undergo apoptosis when placed in culture. Additionally, alpha(2)-macroglobulin, a protease inhibitor and cytokine carrier, and N:-acetylcysteine, an antioxidant, increased the survival of PGCs in vitro. While other protease inhibitors tested did not affect survival of PGCs, all antioxidants tested improved survival of PGCs (P: < 0.05). Further results indicated that the beneficial effect of the antioxidants was critical only during the initial period of culture. Finally, it was determined that in short-term culture, in the absence of feeder layers, antioxidants could partially replace the effect(s) of growth factors and reduce apoptosis. Collectively, these results indicate that the addition of alpha(2)-macroglobulin and antioxidants can increase the number of PGCs in vitro by suppressing apoptosis.

Antiherpetic activities of acidic protein bound polysacchride isolated from Ganoderma lucidum alone and in combinations with acyclovir and vidarabine

To investigate antiherpetic activity, an acidic protein bound polysaccharide (APBP) was isolated from carpophores of Ganoderma lucidum. This brownish APBP was isolated from water soluble substances of the carpophores by activity-guided isolation method. APBP was tested for its antiviral activity against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) by plaque reduction assay in tissue culture. APBP showed potent antiviral activity against HSV-1 and HSV-2 in Vero cells at its 50% effective concentration (EC(50)) of 300 and 440 microg/ml, respectively. APBP had no cytotoxicity on Vero cells at a concentration of 1 x 10(4) microg/ml. APBP exhibited a potent antiviral activity with selectivity index (SI) of more than 22.73. The combined antiherpetic effects of APBP with nucleoside antiherpetic agents, acyclovir (ACV) and vidarabine (ara-A), were examined on the multiplication of these two strains of herpesviruses in Vero cells by the combination assay. The results of combination assay were evaluated by the combination index (CI) that was calculated by the multiple drug effect analysis. CI values were in the range 0.47-0.51 for a combination of APBP with ACV, and in the range of 1.02-1.18 for a combination of APBP with ara-A. The combinations of APBP with ACV on HSV-1 and HSV-2 showed potent synergistic effects, and these results suggest that the possibility of developing APBP as a new antiherpetic agent.

Stat5 is essential for the myelo- and lymphoproliferative disease induced by TEL/JAK2

STAT5 is activated in a broad spectrum of human hematologic malignancies. We addressed whether STAT5 activation is necessary for the myelo- and lymphoproliferative disease induced by TEL/JAK2 using a genetic approach. Whereas mice transplanted with bone marrow transduced with retrovirus expressing TEL/JAK2 develop a rapidly fatal myelo- and lymphoproliferative syndrome, reconstitution with bone marrow derived from Stat5ab-deficient mice expressing TEL/JAK2 did not induce disease. Disease induction in the Stat5a/b-deficient background was rescued with a bicistronic retrovirus encoding TEL/JAK2 and Stat5a. Furthermore, myeloproliferative disease was induced by reconstitution with bone marrow cells expressing a constitutively active mutant, Stat5a, or a single Stat5a target, murine oncostatin M (mOSM). These data define a critical role for Stat5a/b and mOSM in the pathogenesis of TEL/JAK2 disease.

Accelerated hyperfractionation in patients with non-small cell bronchogenic cancers as a cost-effective and user- and patient-friendly schedule

We developed an accelerated hyperfractionation schedule with acceptable effect and toxicity in non-small cell bronchogenic carcinomas. An evolutionary institutional pilot was initiated in March 1995 as a modification of Radiation Therapy Oncology Group (RTOG) 9205, thrice-daily fractionation schedule. Twenty-nine patients with bronchogenic and 7 with head and neck cancers had treatment initiated and completed. A dose of 1.2 Gy was delivered to a mediastinal plus tumor field concomitantly with synchronous boost of 0.6 Gy to a limited volume of gross tumor (twice daily for 21 treatments days in 4 weeks) with a total dose being 75.60 Gy to the primary gross tumor and 50.4 Gy to the elective volume. The bronchogenic cancers were stages IB (medically unresectable, n = 3), IIB (n = 4), IIIA (n = 4), or IIIB (n = 18). Eleven patients had squamous cell cancers, 13 adenocarcinomas, 1 large cell, and 2 carcinomas not specified. With 12 months median follow-up, tolerance has been excellent without any patient complaining of at least Oncology Nursing Society (ONS) grade 3 esophagitis; treatment interruptions occurred in only one patient after 8 days. Weight loss occurred in 12 patients, averaging 4.8% for these patients and 2% overall. Seven patients had a complete response and 20 a partial response. Median survival was 12 months, 1-year survival 58%, 2-year 21%, and 3-year 18%. Seven patients with bronchogenic cancer are still alive. Seven head and neck cancer patients were treated, in which five had base of tongue tumors stage T2 to 4, N0 to N1. Pharyngitis and mucositis were problematic in at least four patients. The outcomes are comparable with other RTOG experience. Hyperfractionated synchronous concomitant boost of total tumor dose to 75.6 Gy in 4 weeks for bronchogenic patients was well tolerated and acceptable to physicians and patients.

Designs and syntheses of oxathiin carboxanilide analogues and their antiviral activities

Syntheses of new analogues of oxathiin carboxanilide (UC84) and their antiviral activities were described. The heterocyclic carboxylic acids including oxathiins (4), thiazines (9) and dithiins (13) in which the methyl was replaced either by lipophilic trifluoromethyl- or bulky phenyl-group were synthesized starting from beta-keto esters (5). Reaction of 4, 9 and 13 with thionyl chloride followed by treatment of the substituted aniline 22 gave the corresponding carboxanilides (24a-24f). The carboxanilides were subjected to Laweson's reagent the corresponding thiocarboxanilides (24g-24k). The antiviral activities of the synthesized compounds against human immunodeficiency virus type 1 (HIV-1), poliovirus type 1 (PV-1), coxsackie B virus type 3 (CoxB-3), vesicular stomatitis virus (VSV) and herpes simplex virus type 1 (HSV-1) were presented. The antiviral activity against HIV-1 of dithiin carboxanilide (24e) was similar with that of UC84 (24a). The corresponding thiocarboxanilides (24g-24k) showed higher inhibitory activity against HIV-1 than the carboxanilides (24a, 24b, 24d, 24e). The compounds in which ether the lipophilic trifluoromethyl substituents (24d, 24f, 24i, 24k) or bulky phenyl substituent is present in the heterocyclic compounds showed lower inhibitory activity than that of the methyl substituents is present in the compounds against the HIV-1. But the trifluoromethylated dithiin (24f) showed higher inhibitory activity against PV-1 and CoxB-3 virus than commercial antiviral agents, ribavirin (RV).

The need for long-term surveillance for patients treated with curative radiotherapy for Hodgkin's disease: University of Minnesota experience

PURPOSE

To examine the long-term outcome of Stage I, II, and III patients treated with curative radiotherapy for Hodgkin's disease at the University of Minnesota Hospital, with particular focus on long-term treatment-related complications and the need for long-term surveillance after treatment.

METHODS AND MATERIALS

A total of 210 Stage I, II, and III patients (98 female, 112 male) treated at the University of Minnesota since 1970 were included in this study. All patients were laparotomy staged. Between 1970 and 1974, 35 high-risk patients (i.e., patients with large mediastinal mass, and/or hilar disease, and/or splenic involvement) and 40 low-risk patients were treated with standard field radiotherapy. From 1975 on, 67 high-risk patients received radical radiotherapy because of poor outcomes with standard radiotherapy, and 68 low-risk patients received standard radiotherapy. Salvage chemotherapy was given to 62 patients who recurred. Median follow-up for all patients was 15.6 years (range 0. 35-26.5 years). Long-term complications after treatment were assessed using standardized incidence ratios (SIR) and mortality ratios (SMR), with particular focus on cardiac complications and secondary malignancies.

RESULTS

By study end, 70% of the patients are alive and 70% had never recurred. Complications included 33 second malignancies and 75 cardiovascular events. Patients treated for Hodgkin's disease had about 7 times the risk of dying from cardiac problems (SMR = 7.2) and 10 times the risk of dying from a second malignancy (SMR = 10.3) compared to the general population. In terms of absolute risk, Hodgkin's disease would cause seven additional deaths from secondary malignancies per year among 1000 patients and four additional deaths from cardiac problems.

CONCLUSION

Hodgkin's disease patients treated successfully with radiotherapy are at an increased risk for developing long-term treatment-related cardiac disease and/or second malignancies. Careful monitoring of these patients is essential to manage morbidity and minimize mortality from these complications. Suggestions for the establishment of worldwide surveillance programs for these patients are proposed.

A case-controlled study on the use of HBsAg-positive donors for allogeneic hematopoietic cell transplantation

To compare the clinical and serological outcomes of patients receiving donors' marrow positive or negative for hepatitis B surface antigen (HBsAg), we studied 18 patients of allogeneic hematopoietic cell transplantation receiving HBsAg-positive marrow (group 1) and 18 receiving HBsAg-negative marrow (group 2). The recipients of the 2 groups were matched for hepatitis B virus (HBV) serology, sex, age, underlying hematological diseases, conditioning regimen, and prophylaxis against graft-versus-host diseases. Eight (44.4%) recipients in group 1 and 2 (11.1%) in group 2 suffered from HBV-related hepatitis posttransplant (P =.03). Furthermore, HBV-related hepatic failure was seen in 6 group 1 patients, but in none of the group 2 patients (P =.007). Five of the 9 (55.5%) HBsAg-negative recipients in group 1 became positive after receiving HBsAg-positive marrow. Serum HBV DNA was positive in all 5 donors of these patients, but in none of the donors of recipients who remained HBsAg negative (P =.008). Group 1 patients developing HBV-related hepatitis posttransplant were more likely to have a donor carrying a precore A(1896 )and/or core promoter T(1762)/A(1764) HBV variant (62. 5% versus 0%, P =.007). This study has demonstrated that a high incidence of HBV-related hepatitis was associated with the use of HBsAg-positive marrow for transplant, and a high viral load in the donor appeared to predispose recipients to the development of HBV-related hepatitis posttransplant. Further clinical trials will be necessary to determine the optimal management approach to this problem, including the use of the antiviral agents in the donors and the recipients. (Blood. 2000;96:452-458)

Gene-expression profile of the ageing brain in mice

Ageing of the brain leads to impairments in cognitive and motor skills, and is the major risk factor for several common neurological disorders such as Alzheimer disease (AD) and Parkinson disease (PD). Recent studies suggest that normal brain ageing is associated with subtle morphological and functional alterations in specific neuronal circuits, as opposed to large-scale neuronal loss. In fact, ageing of the central nervous system in diverse mammalian species shares many features, such as atrophy of pyramidal neurons, synaptic atrophy, decrease of striatal dopamine receptors, accumulation of fluorescent pigments, cytoskeletal abnormalities, and reactive astrocytes and microglia. To provide the first global analysis of brain ageing at the molecular level, we used oligonucleotide arrays representing 6,347 genes to determine the gene-expression profile of the ageing neocortex and cerebellum in mice. Ageing resulted in a gene-expression profile indicative of an inflammatory response, oxidative stress and reduced neurotrophic support in both brain regions. At the transcriptional level, brain ageing in mice displays parallels with human neurodegenerative disorders. Caloric restriction, which retards the ageing process in mammals, selectively attenuated the age-associated induction of genes encoding inflammatory and stress responses.

Quaternized wood as sorbent for reactive dyes

Various species of local wood modified with N-(3-chloro-2-hydroxypropyl)-trimethylammonium chloride showed sorption enhancement for hydrolyzed Reactive Blue 2 (HRB) compared to the untreated samples. The enthalpy of sorption of HRB on Simpoh (Dillenia suffruticosa) was found to be endothermic. Maximum sorption capacity calculated from the Langmuir isotherm was 250.0 mg/g. Under continuous flow conditions HRB could be successfully removed. Dye removal was a function of bed depth and flow rate. However, the bed depth service time model of Bohart and Adams was not applicable in the HRB-quaternized wood system. The modified wood was applied to a sample of industrial textile effluent, and it was found to be able to remove the color successfully under batch conditions.

A mouse thymic stromal cell line producing macrophage-colony stimulating factor and interleukin-6

A thymic stromal cell line, TFGD, was established from a thymic tumor mass developed spontaneously in p53 knock out mouse, and was found to produce cytokines that could induce bone marrow hematopoietic stem cells (HSCs) to differentiate into macrophages. The cytokines produced by the TFGD line were assessed by immunoassays. High level of macrophage-colony stimulating factor (M-CSF) and interleukin (IL)-6 was detected in the TFGD-culture supernatant, whereas granulocyte/macrophage-colony stimulating factor (GM-CSF), IL-3, IL-4, IL-5, IL-13, or interferon (IFN)-gamma was undetectable. Blocking experiments showed that anti-M-CSF monoclonal antibody could neutralize the differentiation-inducing activity shown by the TFGD-culture supernatant. Dot blot analysis of the total RNA isolated from the cultured fetal thymic stromal cells showed that M-CSF transcripts were expressed in the normal thymus. These observations, together with the earlier finding that M-CSF plus IL-6 is the optimal combination of cytokines for the induction of macrophage differentiation from HSCs in vitro, may indicate that thymic macrophages could be generated within the thymus by cytokines involving M-CSF.

Osteoconduction at porous hydroxyapatite with various pore configurations

To assess the histological response and the reinforcing effects of bone ingrowth within porous hydroxyapatite (HA) implants depending on pore geometry, four kinds of cylindrical-type with parallel linear pores phi50, 100, 300, 500 microm), one kind of sponge-type with irregular interconnecting pores (phi250 microm) and one cross-type with crossing linear pores (phi100 x 120 microm) of porous HA were prepared. Eighty-four rabbits were divided into six groups, and a 5 x 5 x 7 mm sized porous HA block was inserted through the medial cortical window of the proximal tibia. Histomorphological changes were examined using light and scanning electron microscopy. A biomechanical compression test was performed using material test machines. After implantation, the implants showed different histological changes depending on pore geometry. Active osteoconduction was also found in the phi50 microm sized cylindrical-type porous HA. Evidence of remodeling of new bone and bone marrow formation within porous HA was found in the larger cylindrical-types (phi300, 500 microm), and the sponge- and cross-types. The biomechanical test showed that the ultimate compressive strength increased significantly in the phi300 microm sized cylindrical-type, and in the sponge- and cross-types eight weeks after implantation. Porous HA with cylindrical pores could be a useful graft material due to its strength, osteoconductivity and the ease with which its pore geometry can be controlled.

Association between hepatitis B virus infection and HLA-DR type in Korea

Although the mechanism of susceptibility to chronic persistent hepatitis B virus (HBV) infection is not well clarified, immunogenetic factors of the host may have a role. Recently, a strong association between HLA-DR13 and the self-limited course of HBV infection has been reported. To determine whether the elimination of HBV is related to a particular HLA allele, we studied the HBV markers and HLA-DR phenotypes of 1,272 Koreans who had visited Yonsei University Medical Center for renal transplantation. They included 330 renal transplant donors. Subjects were categorized into 3 different groups: the "Unexposed Group" (UE; n = 946) with negative HBV markers, the "Chronic Carrier Group" (CC; n = 83), who were hepatitis B surface antigen (HBsAg)-positive, and the "Spontaneously Cleared Group" (SC; n = 243), who were HBsAg-negative with antibodies to HBsAg (anti-HBs) and hepatitis B core antigen (anti-HBc). HLA-DR4 was the most common type in all groups. HLA-DR6 was significantly more frequent in 69 of 243 subjects with SC (28. 4%) than in 8 of 83 subjects with CC (9.6%) (P <.001; relative risk [RR] = 3.72). HLA-DR9 was significantly more frequent in CC than in SC (P <.001; RR = 0.33). HLA-DR13 showed a stronger association with the clearance of HBV than the other HLA-DR6 subgroup. The distribution of HLA-DR phenotypes was similar regardless of renal disease. Our data indicate that HLA-DR6, especially HLA-DR13, is one of the host factors, which influences the immune response to HBV, and may be associated with self-elimination of HBV in Koreans.

Four new terpenes from the pericarp of Platycladus orientalis

A new monoterpene, platydiol (1), and three new diterpenes, platyclolactonic acid (2), 14,15-bisnor-8(17)-labdene-16,19-dioic acid (3), and 6,7-dehydrosandaracopimaric acid (4), were isolated from the pericarp of Platycladus orientalis. Their structures were elucidated by spectral and chemical methods.

Six podocarpane-type trinorditerpenes from the bark of Taiwania cryptomerioides

Six podocarpane-type trinorditerpenes were isolated from the bark of Taiwania cryptomerioides. Their structures, 14-hydroxy-13-methoxy-8,11,13-podocarpatrien-7-one (1), 13-hydroxy-12-methoxy-8,11,13-podocarpatriene (2), 12-hydroxy-13-methoxy-8,11,13-podocarpatriene (3), 14-hydroxy-13-methoxy-8,11,13-podocarpatriene (4), 13-hydroxy-8,11,13-podocarpatriene (5), and 13,14-dihydroxy-8,11,13-podocarpatrien-7-one (6), were determined principally from spectral evidence.

The role of virus-specific CD8(+) cells in liver damage and viral control during persistent hepatitis B virus infection

Hepatitis B virus (HBV) is a noncytopathic virus, and the recognition of infected hepatocytes by HBV-specific CD8 cells has been assumed to be the central mechanism causing both liver damage and virus control. To understand the role of cytotoxic T cells in the pathogenesis of HBV infection, we used functional assays that require T cell expansion in vitro and human histocompatibility leukocyte antigen (HLA)-peptide tetramers that allow direct ex vivo quantification of circulating and liver-infiltrating HBV-specific CD8 cells. Two groups of patients with persistent HBV infection were studied: one without liver inflammation and HBV replication, the other with liver inflammation and a high level of HBV replication. Contrary to expectation, a high frequency of intrahepatic HBV-specific CD8 cells was found in the absence of hepatic immunopathology. In contrast, virus-specific T cells were more diluted among liver infiltrates in viremic patients, but their absolute number was similar because of the massive cellular infiltration. Furthermore, inhibition of HBV replication was associated with the presence of a circulating reservoir of CD8(+) cells able to expand after specific virus recognition that was not detectable in highly viremic patients with liver inflammation. These results show that in the presence of an effective HBV-specific CD8 response, inhibition of virus replication can be independent of liver damage. When the HBV-specific CD8 response is unable to control virus replication, it may contribute to liver pathology not only directly but by causing the recruitment of nonvirus-specific T cells.