Oral bisphosphonate-related osteonecrosis of the jaw: the first report in Asia

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a serious side effect of bisphosphonate therapy. The incidence of BRONJ is known to be low among patients treated with oral bisphosphonates. We investigated the prevalence, demographics, clinical manifestations, and treatment outcome of 24 patients with oral BRONJ in Asian populations.

INTRODUCTION

The long-term safety of oral bisphosphonates is clinically important considering the rare but potentially serious complications such as bisphosphonate-related osteonecrosis of the jaw (BRONJ) versus the effect of reducing and preventing osteoporotic fracture. The incidence of BRONJ is known to be low among patients treated with oral bisphosphonates around the world. However, the prevalence in those taking oral bisphosphonates for osteoporosis in Asian populations is unknown. Moreover, a recent article, showing that the majority of reported patients who received alendronate were Asian American, raised concern about the prevalence of oral BRONJ in Asian populations. The objective of this study was to investigate the estimated prevalence, clinical characteristics, and treatment outcome of oral BRONJ in Asian populations.

METHODS

From October 2005 to December 2008, a retrospective review of medical charts identified 24 patients receiving oral bisphosphonates diagnosed as BRONJ at the Department of Oral and Maxillofacial Surgery, Yonsei University Dental Hospital, Seoul, South Korea.

RESULTS

The estimated prevalence of oral BRONJ was 0.05-0.07%. The average oral bisphosphonate treatment duration was 43.1 months (range, 5-120 months). Treatment with oral antibiotics and/or surgery including sequestrectomy or alveolectomy showed relatively favorable results.

CONCLUSIONS

The prevalence of oral BRONJ in Korea is similar to that reported previously in Western populations. We suggest that recognition of BRONJ and appropriate management pre- and post-dental surgery might reduce the frequency of BRONJ among patients receiving oral bisphosphonates.

Distinct effects on M2-type pyruvate kinase are involved in the dimethylsulfoxide-induced modulation of cellular proliferation and degranulation of mast cells

Dimethylsulfoxide (DMSO), a universal solvent, is frequently used to dissolve various classes of chemicals for the evaluation of their biological activities. In one such evaluation, we noticed that DMSO itself caused cellular proliferation and interfered with high affinity IgE receptor (FcepsilonRI)-mediated degranulation of mast cells. DMSO caused cellular proliferation of RBL-2H3 cells by phosphorylating both extracellular-signal regulated kinase (ERK) and M2-type pyruvate kinase (M2PK) through which the enzymatic activity of M2PK was reduced. Allergenic activation of FcepsilonRI caused the tyrosine phosphorylations of signaling components of FcepsilonRI, such as Syk, PLCgamma1, PLCgamma2, ERK, and M2PK. In these allergenic activated RBL-2H3 cells, DMSO specifically inhibited FcepsilonRI-mediated tyrosine phosphorylation of M2PK, blocked FcepsilonRI-mediated inhibition of the enzymatic activity of M2PK, and then inhibited FcepsilonRI-mediated degranulation. These results suggest that DMSO causes cellular proliferation and mast cell degranulation through differential modulation of M2PK in resting and allergenic activated cells.

Agonist-induced endocytosis and receptor phosphorylation mediate resensitization of dopamine D(2) receptors

The regulatory mechanisms and functional roles of agonist-induced internalization of G protein-coupled receptors (GPCRs) were analyzed using mutant dopamine D(2) receptors (D(2)Rs) in which all possible GPCR kinase (GRK) phosphorylation sites were mutated or the affinity for beta-arrestins was altered. Agonist-induced internalization of D(2)Rs involved a phosphorylation-dependent component, which was mediated by serine/threonine (S/T) residues in the second loop and T225 in the third loop, and a phosphorylation-independent component. GRK2-mediated enhancement of the internalization and inhibition of D(2)R signaling did not involve receptor phosphorylation, and only the former required the enzymatic activity of GRK2. The phosphorylation-deficient mutant (D(2)R-intracellular loop 2/3) recycled more slowly and showed more agonist-induced desensitization than did the wild-type D(2)R, suggesting that receptor phosphorylation mediates the recycling of the internalized receptors and enhances receptor resensitization. Blockade of the agonist-induced internalization of D(2)R-intracellular loop 2/3 provoked desensitization as in wild-type D(2)R, suggesting that certain cellular processes other than receptor dephosphorylation occurring within the endocytic vesicle are responsible for the resensitization of D(2)R. When dissociation between D(2)R and beta-arrestin was inhibited or when the expression of cellular beta-arrestins was decreased, agonist-induced desensitization of D(2)R did not occur, suggesting that dissociation from beta-arrestin is the main cellular process required for resensitization of D(2)R and is achieved through agonist-induced internalization. These results indicate that, in the regulation of some GPCRs, phosphorylation-independent association with beta-arrestin plays a major role in agonist-induced desensitization.

Transcatheter arterial chemoembolization vs. chemoinfusion for unresectable hepatocellular carcinoma in patients with major portal vein thrombosis

BACKGROUND

Transcatheter arterial chemoembolization (TACE) has been limited in palliative treatment of unresectable hepatocellular carcinoma (HCC) with major portal vein (PV) invasion due to the possibility of liver failure following embolization. Transcatheter arterial chemoinfusion (TACI) has been an option in such cases.

AIM

To compare clinical outcomes after TACE vs. TACI in HCC patients with major PV occlusion.

METHODS

We compared clinical outcomes after TACE vs. TACI in HCC patients with major PV occlusion. From 2005 to 2007, 110 HCC patients with major PV thrombosis were treated with TACE (n = 49) or TACI (n = 61).

RESULTS

The morbidity rate was similar for both TACE (6.1%) and TACI (6.5%) patients, and complications were adequately managed using medical treatment. The Kaplan-Meier survival analysis showed that the survival period was significantly longer for the TACE group (median: 14.9 months) than for the TACI (median: 4.4 months) group (P < 0.001). There was a higher probability of death in the TACI group than in the TACE group in both our multivariate Cox-proportional hazards (OR 3.09, P < 0.001) and the propensity score-matched (27 pairs) cohort analyses (OR 2.27, P = 0.024).

CONCLUSIONS

Transcatheter arterial chemoembolization can be safely performed in HCC patients with main PV occlusion. Compared with TACI, TACE may result in longer survival of HCC patients with major PV occlusion.

Intrapulmonary shunt in the course of pediatric liver transplantation

The hepatopulmonary syndrome occurs when an intrapulmonary shunt (IPS) causes hypoxemia in patients with cirrhosis. Because IPS has not been clearly defined in children, we investigated the prevalence, clinical characteristics, and outcomes of IPS in children undergoing liver transplantation (OLT). Of the 107 pediatric OLT recipients between December 1994 and March 2005, 18 (16.8%) had IPS, as evaluated by contrast-enhanced echocardiography (CEE) at 9 months to 16 years of age. The degree of IPS was classified into five grades according to the extent of microbubbles in the left ventricle, with significant IPS defined as grade II or higher. Baseline characteristics, including serum total bilirubin, albumin, aminotransferase, and prothrombin time, did not differ in patients with or without IPS. The patients with IPS had significantly lower Pao2 and Sao2, longer duration of mechanical ventilation and hospital stay, and higher postoperative morbidity and mortality than patients without IPS (P < .05 each), but there were no other significant differences between the groups. The six patients with significant IPS (one grade II, three grade III, and two grade IV) showed a significantly greater morbidity and mortality than patients with grade I IPS (P < .05). Most of the positive CEE findings of IPS regressed within 6 months after OLT. These findings indicated that IPS is not uncommon among children undergoing OLT, but is reversible. Because severe IPS may increase patient morbidity and mortality, early assessment of IPS status using CEE is essential for pediatric OLT candidates.

Involvement of the BLT2 receptor in the itch-associated scratching induced by 12-(S)-lipoxygenase products in ICR mice

BACKGROUND AND PURPOSE

Recently, we reported that 12(S)-HPETE (12(S)-hydroperoxyeicosa-5Z,8Z,10E,14Z-tetraenoic acid) induces scratching in ICR mice. We hypothesized that 12(S)-HPETE might act as an agonist of the low-affinity leukotriene B4 receptor BLT2. To confirm the involvement of the BLT2 receptor in 12(S)-HPETE-induced scratching, we studied the scratch response using the BLT2 receptor agonists compound A (4'-[[pentanoyl (phenyl) amino]methyl]-1,1'-biphenyl-2-carboxylic acid) and 12(S)-HETE (12(S)-hydroxyeicosa-5Z,8Z,10E,14Z-tetraenoic acid).

EXPERIMENTAL APPROACH

A video recording was used to determine whether the BLT2 receptor agonists caused itch-associated scratching in ICR mice. Selective antagonists and several chemicals were used.

KEY RESULTS

Both 12(S)-HETE and compound A dose dependently induced scratching in the ICR mice. The dose-response curve for compound A showed peaks at around 0.005-0.015 nmol per site. Compound A- and 12(S)-HETE-induced scratching was suppressed by capsaicin and naltrexon. We examined the suppressive effects of U75302 (6-[6-(3-hydroxy-1E,5Z-undecadienyl)-2-pyridinyl]-1,5-hexanediol, the BLT1 receptor antagonist) and LY255283 (1-[5-ethyl-2-hydroxy-4-[[6-methyl-6-(1H-tetrazol-5-yl)heptyl]oxy]phenyl]-ethanone, the BLT2 receptor antagonist) on the BLT2 agonist-induced scratching. LY255283 suppressed compound A- and 12(S)-HETE-induced scratching, but U75302 did not. LY255283 required a higher dose to suppress the compound A-induced scratching than it did to suppress the 12(S)-HETE-induced scratching. One of the BLT(2) receptor agonists, 12(R)-HETE (12(R)-hydroxyeicosa-5Z,8Z,10E,14Z-tetraenoic acid), also induced scratching in the ICR mice.

CONCLUSIONS AND IMPLICATIONS

Our present results corroborate the hypothesis that the BLT2 receptor is involved in 12(S)-lipoxygenase-product-induced scratching in ICR mice. We also confirmed that this animal model could be a valuable means of evaluating the effects of BLT2 receptor antagonists.

Roles of conserved intracellular sequences regions for the proper expression of dopamine D(2) and D(3) receptors

The dopamine D(2) receptor and D(3) receptor (D(2)R, D(3)R) have high homology in both their amino acid composition and signaling pathways. Virtually all signaling pathways reported thus far overlap between the two receptors with the exception that the D(3)R signals are 2 approximately 5 times less efficient than D(2)R. Previous studies have suggested that conformational constraints of D(3)R might be responsible for the poor coupling with the G protein. To this hypothesis, point mutations were introduced into some of the conserved regions between D(2)R and D(3)R, and their effects on receptor expression were investigated. Among the four conserved intracellular receptor regions examined (TTT motif in the 1(st) intracellular loop, SS motif in the 2(nd) intracellular loop, YxxL and TxxS/xS motifs in the 3(rd) intracellular loop), a mutation of the Thr-Thr-Thr (TTT) motif in the first intracellular loop or the LxxY motif in the 3(rd) intracellular loop markedly decreased the level of D(3)R expression compared with D(2)R. The TTT motif was further mutated individually or in combination to test which residue plays a critical role on the expression of the receptor proteins. Different amino acids between D(2)R and D(3)R in the 1(st) intracellular loop were exchanged to determine if the adjacent amino acid residues are responsible for the differences between D(2)R and D(3)R. The first two threonine residues become more important when the individual threonine residue is mutated. However, all three intact threonine residues are essential for proper expression of the receptor proteins. The neighboring sequences around the triplet threonine residues in the 1(st) loop of D(3)R are not important for proper positioning of the receptor proteins on the plasma membrane. It was concluded that D(2)R has a more flexible overall conformation that can accept mutated residues in the intracellular region than D(3)R, which might be partly responsible for the quantitative differences in the signaling efficiency between D(2)R and D(3)R.

Characterization of functional roles of DRY motif in the 2nd intracellular loop of dopamine D2 and D3 receptors

Dopamine D(2)R and D(3)R (D(2)R, D(3)R) show very high sequence homology and employ virtually identical signaling pathways even though D(2)R is 2 approximately 5 times more active. Among the structural motifs identified, a triplet sequence, Asp-Arg-Tyr (DRY motif), plays critical roles in the determination of receptor conformations for signaling and intracellular trafficking of G protein-coupled receptors by forming intramolecular interactions. Thus, it is possible that different signaling efficiencies of D(2)R and D(3)R might be caused by the receptor activation levels stabilized by their own DRY motifs. In this study, the Arg and Asp residues of D(2)R and D(3)R were mutated, and resulting changes in their signaling and intracellular trafficking properties were comparatively studied. Mutation of the Arg residues of D(2)R and D(3)R abolished their signaling but differently affected their intracellular localizations. The wildtype and R132H-D(2)R were expressed mainly on the plasma membrane. On the other hand, compared with the wildtype D(3)R, a substantial amount of R128H-D(3)R was localized intracellularly. The expression of receptor proteins on the plasma membrane and their signaling efficiencies were more drastically affected by the mutation of the Asp residue of D(3)R than D(2)R. Therefore, it was concluded that the different levels of conformational strain exerted by the DRY motif might partly determine the quantitative differences in the signaling efficiencies between D(2)R and D(3)R.

Polymorphisms in the type IV collagen alpha3 gene and the risk of COPD

A number of genome-wide linkage analyses have identified the 2q33.3-2q37.2 region as the most likely to contain the genes that contribute to the susceptibility to chronic obstructive pulmonary disease (COPD). It was hypothesised that the type IV collagen alpha3 (COL4A3) gene, which is one of the genes located in the 2q33.3-2q37.2 region, may act as a low-penetrance susceptibility gene for COPD. To test this hypothesis, the association of COL4A3 -1162T>C, IVS2+12C>A, P141L, G162E, H451R, P574L and *315C>A polymorphisms with the risk of COPD was investigated in a case-control study of 311 COPD patients and 386 controls. The presence of at least one 451R allele was associated with a significantly higher risk of COPD compared with the 451 H/H genotype (adjusted odds ratio 1.48, 95% confidence interval (1.03-2.14)). When the subjects were stratified according to age and COPD severity, the 451R allele was associated with a significantly higher risk of COPD only in younger individuals with severe COPD (3.02 (1.37-6.67)). In conclusion, these findings suggest that the type IV collagen alpha3 gene contributes to the genetic susceptibility to chronic obstructive pulmonary disease.

Anti-allergic prenylated flavonoids from the roots of Sophora flavescens

The bioassay-guided fractionation of the MeOH extract from the root of Sophora flavescens led to the isolation of eight known prenylated flavonoids ( 1 - 8) responsible for the IN VITRO anti-allergic activity. Among them, kushenol N ( 3), sophoraflavanone G ( 6), and leachianone A ( 7) demonstrated significant inhibition of the release of beta-hexosaminidase from cultured RBL-2H3 cells with IC (50) values ranging from 15 to 30 muM.

Developmental regulation and functions of the expression of the neuropeptide corazonin in Drosophila melanogaster

Although the corazonin gene (Crz) has been molecularly characterized, little is known concerning the function of this neuropeptide in Drosophila melanogaster. To gain insight into Crz function in Drosophila, we have investigated the developmental regulation of Crz expression and the morphology of corazonergic neurons. From late embryo to larva, Crz expression is consistently detected in three neuronal groups: dorso-lateral Crz neurons (DL), dorso-medial Crz neurons (DM), and Crz neurons in the ventral nerve cord (vCrz). Both the vCrz and DM groups die via programmed cell death during metamorphosis, whereas the DL neurons persist to adulthood. In adults, Crz is expressed in a cluster of six to eight neurons per lobe in the pars lateralis (DLP), in numerous neuronal cells in the optic lobes, and in a novel group of four abdominal ganglionic neurons present only in males (ms-aCrz). The DLP group consists of two subsets of cells having different developmental origins: embryo and pupa. In the optic lobes, we have detected both Crz transcripts and Crz promoter activity, but no Crz-immunoreactive products, suggesting a post-transcriptional regulation of Crz mRNA. Projections of the ms-aCrz neurons terminate within the ventral nerve cord, implying a role as interneurons. Terminals of the DLP neurons are found in the retrocerebral complex that produces juvenile hormone and adipokinetic hormone. Significant reduction of trehalose levels in adults lacking DLP neurons suggests that DLP neurons are involved in the regulation of trehalose metabolism. Thus, the tissue-, stage-, and sex-specific expression of Crz and the association of Crz with the function of the retrocerebral complex suggest diverse roles for this neuropeptide in Drosophila.

Effects of steeping conditions of waxy rice on the physical and sensory characteristics of gangjung (a traditional Korean oil-puffed snack)

The objectives of this study were to investigate the effects of steeping period (1, 11, and 21 d) and temperature (15, 25, and 35 degrees C) of waxy rice on the physical and sensory characteristics of Gangjung (a traditional Korean oil-puffed snack). Increasing the steeping period from 1 to 21 d and increasing the temperature from 15 to 35 degrees C markedly increased the oil absorption ratio of Gangjung. Textural analysis indicated that the number of peaks (representing the internal air cell characteristics) for Gangjung decreased in proportion with increasing steeping temperature and period, but that the hardness was affected significantly only by steeping period. Regarding the sensory characteristics of Gangjung, 5 appearance, 7 flavor, and 9 texture attributes were developed and evaluated by trained descriptive panelists. When the steeping temperature and the steeping period were increased, the degree of expansion, size, and degree of external roughness increased, while the strength of external color decreased. Regarding the flavor attributes, the intensity of sweetness and toasted carbohydrate food flavor tended to decrease with increasing steeping temperature and period, while sourness and butyric acid flavor, which are related to the fermentation of waxy rice, increased. Finally, the increased steeping temperature and period decreased the intensity of hardness, crispness, and toughness of Gangjung but increased the degree of fracture, degree of melting, and oiliness.

Roles of Protein Kinase C and Actin-Binding Protein 280 in the Regulation of Intracellular Trafficking of Dopamine D3 Receptor

D3 dopamine receptor (D3R) is expressed mainly in parts of the brain that control the emotional behaviors. It is believed that the improper regulation of D3R is involved in the etiology of schizophrenia. Desensitization of D3R is weakly associated with G protein-coupled receptor kinase (GRK)/β-arrestin-directed internalization. This suggests that there might be an alternative pathway that regulates D3R signaling. This report shows that D3R undergoes robust protein kinase C (PKC)-dependent sequestration that is accompanied by receptor phosphorylation and the desensitization of signaling. PKC-dependent D3R sequestration, which was enhanced by PKC-β or -δ, was dynamin dependent but independent of GRK, β-arrestin, or caveolin 1. Site-directed mutagenesis of all possible phosphorylation sites within the intracellular loops of D3R identified serine residues at positions 229 and 257 as the critical amino acids responsible for phorbol-12-myristate-13-acetate (PMA)-induced D3R phosphorylation, sequestration, and desensitization. In addition, the LxxY endocytosis motif, which is located between residues 252 and 255, was found to play accommodating roles for PMA-induced D3R sequestration. A continuous interaction with the actin-binding protein 280 (filamin A), which was previously known to interact with D3R, is required for PMA-induced D3R sequestration. In conclusion, the PKC-dependent but GRK-/β-arrestin-independent phosphorylation of D3R is the main pathway responsible for the sequestration and desensitization of D3R. Filamin A is essential for both the efficient signaling and sequestration of D3R.

Role of cyclooxygenase-2 in tetrahydrobiopterin-induced dopamine oxidation

Dopamine is considered one of the main contributing factors in the induction of oxidative stress and selective dopaminergic neurodegeneration in Parkinson's disease. We have previously reported that tetrahydrobiopterin (BH4) leads to dopamine oxidation and renders dopamine-producing cells vulnerable. In the present study, we found that BH4 selectively upregulates cyclooxygenase-2 (COX-2) expression in dopaminergic cells. BH4 caused an induction of COX-2 mRNA, and a critical regulatory motif for BH4-induced transcriptional activation of COX-2 is CRE/AP-1. COX-2 can oxidize dopamine and cause oxidative stress, which is evidenced by the findings that significant increase in dopamine-chrome formation and protein carbonyl contents by BH4-induced COX-2 up-regulation, and the increases are abolished by COX-2 selective inhibitor meloxicam. Increased COX-2 promotes dopaminergic neurodegeneration in both SH-SY5Y cells and rat mesencephalic neurons. These data suggest that BH4-induced COX-2 expression is responsible for dopamine oxidation, leading to the preferential vulnerability of dopaminergic cells in Parkinson's disease.

Overexpression of D2/D3 receptors increases efficacy of ropinirole in chronically 6-OHDA-lesioned Parkinsonian rats

Ropinirole, which is a non-ergot dopamine agonist derivative, exerts therapeutic benefits in Parkinson's disease (PD). Based on recent studies implicating dopamine receptors 2 and 3 (D2R and D3R) as possible targets of ropinirole, we over-expressed these dopamine receptor genes in the dopamine-denervated striatum of rodents to reveal whether their over-expression modulated ropinirole activity. Adult Sprague-Dawley rats initially received unilateral 6-hydroxydopamine lesion of the medial forebrain bundle. At 1 month after surgery, successfully lesioned animals (3 or less forelimb akinesia score, and 8 or more apomorphine-induced rotations/min over 1 h) were randomly assigned to intrastriatal injection (ipsilateral to the lesion) of blank lentiviral vector, D2R, D3R or both genes. At about 5 months post-lesion, ropinirole (0.2 mg/kg, i.p.) was administered daily for 9 consecutive days. The subtherapeutic dose of ropinirole improved the use of previously akinetic forelimb and produced robust circling behavior in lesioned animals with striatal over-expression of both D2R and D3R compared to lesioned animals that received blank vector. In contrast, the subtherapeutic dose of ropinirole generated only modest motor effects in lesioned animals with sole over-expression of D2R or D3R. Western immunoblot and autoradiographic assays showed enhanced D2R and D3R protein levels coupled with normalized D2R and D3R binding in the ventral striatum of lesioned animals with lentiviral over-expression of both D2R and D3R relative to vehicle-treated lesioned animals. Immunohistochemical analyses showed that D2R and D3R GFP fluorescent cells colocalized with enkephalin and substance P immunoreactive medium spiny neurons. These data support the use of the subtherapeutic dose of ropinirole in a chronic model of PD.

Functional interaction between dopamine receptor subtypes for the regulation of c-fos expression

Dopaminergic drugs increase the expression of the proto-oncogene, c-fos, in the brain, which is involved in the coordination of neurobiological changes caused by repeated cocaine or amphetamine use. This study examined the roles of five dopamine receptor subtypes on the c-fos promoter activity. D(1)R or D(5)R significantly increased the expression of c-fos promoter by activating protein kinase A. However, D(2)R, D(3)R, or D(4)R did not show any noticeable effects. The co-expression of D(1)R/D(3)R or D(1)R/D(2)R synergistically activated the basal and agonist-induced expression of the c-fos promoter, respectively. The Ral guanine-nucleotide-dissociation-stimulator-like, which was found to interact with the 3rd cytoplasmic loop of D(3)R, mediated the inhibitory activity of D(3)R in c-fos expression. In summary, the expression of the c-fos promoter was increased by the D1-like receptors and enhanced synergistically by the D2-like receptors via the modulation of cellular cAMP. D(3)R inhibited the expression of the c-fos promoter through an interaction with RGL.

Population pharmacokinetic and pharmacodynamic models of remifentanil in healthy volunteers using artificial neural network analysis

AIMS

An ordinary sigmoid E(max) model could not predict overshoot of electroencephalographic approximate entropy (ApEn) during recovery from remifentanil effect in our previous study. The aim of this study was to evaluate the ability of an artificial neural network (ANN) to predict ApEn overshoot and to evaluate the predictive performance of the pharmacokinetic model, and pharmacodynamic models of ANN with respect to data used.

METHODS

Using a reduced number of ApEn instances (n = 1581) to make NONMEM modelling feasible and complete ApEn data (n = 24 509), the presence of overshoot was assessed. A total of 1077 measured remifentanil concentrations and ApEn data, and a total of 24 509 predicted concentrations and ApEn data were used in the pharmacodynamic model A and B of ANN, respectively. The testing subset of model B (n = 7352) was used to evaluate the ability of ANN to predict overshoot of ApEn. Mean squared error (MSE) was calculated to evaluate the predictive performance of the ANN models.

RESULTS

With complete ApEn data, ApEn overshoot was observed in 66.7% of subjects, but only in 37% with a reduced number of ApEn instances. The ANN model B predicted 77.8% of ApEn overshoot. MSE (95% confidence interval) was 57.1 (3.22, 71.03) for the pharmacokinetic model, 0.148 (0.004, 0.007) for model A and 0.0018 (0.0017, 0.0019) for model B.

CONCLUSIONS

The reduced ApEn instances interfered with the approximation of true electroencephalographic response. ANN predicted 77.8% of ApEn overshoot. The predictive performance of model B was significantly better than that of model A.

Human papillomavirus genotyping using HPV DNA chip analysis in Korean women

This study was designed to investigate the genotypes of human papillomavirus (HPV) in Korean women who had abnormal cervical cytology and to evaluate the clinical accuracy of HPV DNA chip analysis for the diagnosis of cervical neoplasia. Liquid-based cytology preparations, HPV DNA chip analysis, and cervical biopsy were performed in 2358 women. High-risk HPV was identified in 23.5% of 1650 histologically confirmed normal samples (including cervicitis and squamous metaplasia) and in 81.8% of 708 samples with cervical intraepithelial neoplasia (CIN) and carcinoma (P< 0.01). The major prevalent high-risk HPV genotypes in 381 samples of CIN II/III were HPV-16, -58, -33, and -31, in order of prevalence rate (average overall, 78.0%), and HPV-16, -18, -58, and -33 (average overall, 81.2%) in 133 samples of squamous cell carcinoma (SCC). The infection rate of HPV-16 was significantly higher than that of other high-risk HPV genotypes in all normal, CIN, and SCC cases (P< 0.01) and increased with more advanced squamous cervical lesions (P< 0.01). The detection accuracy of high-risk HPV using HPV DNA chip analysis for CIN II or worse was as follows: sensitivity 84% (81–87%), specificity 72% (70–74%), positive predictive value 47% (44–50%), and negative predictive value 94% (92–95%). These results suggest that HPV DNA chip analysis may be a reliable diagnostic tool for the detection of cervical neoplasia and that there are geographic differences in the distribution of high-risk HPV genotypes.

Characterization of the desensitization properties of five dopamine receptor subtypes and alternatively spliced variants of dopamine D2 and D4 receptors

Proper regulation of brain dopaminergic activity is essential for maintaining normal mental functions. In this study, the regulatory properties of five different dopamine receptor subtypes and alternative splicing variants of dopamine D2 and D4 were examined. The stimulation of D1R, D2R, D5R but not D3R, D4R caused the robust translocation of beta-arrestin to the plasma membrane. When D1R or D3R were co-expressed with D2R, D1R significantly inhibited the sequestration of D2R, suggesting that the inhibitory effects of D1R on the D2R sequestration could explain the synergistic activity between two receptors. The sequestration of alternatively spliced isoforms of D2R was differently regulated by GRKs and beta-arrestins. Three alternative splicing variants of D4R produced a similar level of beta-arrestin translocation, and the studies with the deletion mutants of D4R within the third cytoplasmic loop revealed that the regions containing the SH3-binding domains are responsible for the beta-arrestin translocation.

Clathrin required for phosphorylation and internalization of beta2-adrenergic receptor by G protein-coupled receptor kinase 2 (GRK2)

Clathrin is a major component of clathrin-coated pits and serves as a binding scaffold for endocytic machinery through the binding of a specific sequence known as the clathrin-binding motif. This motif is also found in cellular signaling proteins other than endocytic components, including G protein-coupled receptor kinase 2 (GRK2), which phosphorylates G protein-coupled receptors and promotes uncoupling of receptor-G protein interaction. However, the functions of clathrin in the regulation of GRK2 are unknown. Here we demonstrated that overexpression of GRK2 mutated at the clathrin-binding motif with alanine (GRK2-5A) results in inhibition of phosphorylation and internalization of the beta2-adrenergic receptor (beta2AR). However, the interaction of beta2AR with GRK2-5A is the same as that of wild type GRK2 as determined by bioluminescence resonance energy transfer. Furthermore, GRK2-5A phosphorylates rhodopsin essentially to the same extent as wild type GRK2 in vitro. Depletion of the clathrin heavy chain using small interference RNA inhibits agonist-induced phosphorylation and internalization of beta2AR. Thus, clathrin works as a regulator of GRK2 in cells. These results indicate that clathrin is a novel player in cellular functions in addition to being a component of endocytosis.

Evaluation of androgens in the scalp hair and plasma of patients with male-pattern baldness before and after finasteride administration

BACKGROUND

Finasteride, a competitive inhibitor of the enzyme 5alpha-reductase II, is widely used as a medical treatment for patients with male-pattern baldness (MPB), which is affected by the distribution of androgenic steroids. It is also notable that the androgenic effect in MPB is different for each region of the head.

OBJECTIVES

To study the effect of the drug finasteride, we quantified androgenic steroids in the vertex and occipital scalp hair and in the plasma of patients with MPB.

METHODS

The patients with MPB, aged 23-52 years, were treated with finasteride 1 mg daily for 5 months. The hair and plasma samples were hydrolysed, extracted with n-pentane, and derivatized with MSTFA:NH4I:DTE (1000:4:5, v/w/w). We analysed the concentrations of dihydrotestosterone (DHT) and testosterone (T) in the hair and plasma using gas chromatography-mass spectrometry (GC-MS).

RESULTS

In the hair, the ratio of DHT/T was decreased in the vertex scalp hair after the individual received finasteride (P < 0.005). However, we found no significant difference in the ratio of DHT/T in the occipital scalp hair before and after individuals received finasteride. Like the results in the vertex scalp hair, the ratio of DHT/T in the plasma was remarkably decreased after finasteride administration (P < 0.001).

CONCLUSIONS

This study supports the effect of finasteride in patients with MPB by examining the decreased level of DHT/T in scalp hair and in plasma. Thus, in view of the androgenic effect in the different hair regions, the vertex scalp hair plays a more important role for patients with MPB treated with finasteride than does the occipital hair.

Effects of resveratrol on mast cell degranulation and tyrosine phosphorylation of the signaling components of the IgE receptor

The molecular mechanism of how resveratrol inhibits mast cell degranulation was studied by examining its effects on the signaling components of the high affinity IgE receptor (FcepsilonRI) pathway. Resveratrol inhibited mast cell degranulation in a dose-dependent manner and reduced the FcepsilonRI-mediated tyrosine phosphorylation of ERK and PLCgamma1 but not of Syk and PLCgamma2. U-73 122 and PD98059, which are PLC and MEK inhibitors, also had inhibitory effects on mast cell degranulation. These results suggest that FcepsilonRI-mediated tyrosine phosphorylation of PLCgamma1 and ERK could be potential cellular targets of resveratrol for the inhibition of mast cell degranulation.

Relationship between the G protein signaling and homologous desensitization of G protein-coupled receptors

Signaling and desensitization of G protein-coupled receptor are intimately related, and measuring them separately requires certain parameters that represent desensitization independently of signaling. In this study, we tested whether desensitization requires signaling in three different receptors, beta2-adrenergic receptor (beta2AR) in S49 lymphoma cells, alpha-factor pheromone receptor (Ste2p) in Saccharomyces cerevisiae LM102 cells, and dopamine D3 receptor (D3R) in HEK-293 cells. Agonist-induced beta-arrestin translocation to the plasma membrane or receptor sequestration was measured to estimate homologous desensitization. To separate the signaling and desensitization of beta2AR, which mediates stimulation of adenylyl cyclase, S49 lymphoma cys- cells that lack the alpha subunit of Gs were used. Stimulation of beta2AR in these cells failed to increase intracellular cAMP, but beta-arrestin translocation still occurred, suggesting that feedback from beta2AR signaling is not required for homologous desensitization to occur. Agonist-induced sequestration of the yeast Ste2p-L236R, which showed reduced signaling through G protein, was not different from that of wildtype Ste2p, suggesting that the receptor signaling and sequestration are not directly linked cellular events. Both G protein coupling and D3R signaling, measured as inhibition of cAMP production, were greatly enhanced by co-expression of exogenous alpha subunit of Go (Goalpha) or adenylyl cyclase type 5 (AC5), respectively. However, agonist-induced beta-arrestin translocation, receptor phosphorylation, and sequestration were not affected by co-expression of Galphao and AC5, suggesting that the extent of signaling does not determine desensitization intensity. Taken together, our results consistently suggest that G protein signaling and homologous desensitization are independent cellular processes.

A beta-arrestin binding determinant common to the second intracellular loops of rhodopsin family G protein-coupled receptors

beta-Arrestins have been shown to inhibit competitively G protein-dependent signaling and to mediate endocytosis for many of the hundreds of nonvisual rhodopsin family G protein-coupled receptors (GPCR). An open question of fundamental importance concerning the regulation of signal transduction of several hundred rhodopsin-like GPCRs is how these receptors of limited sequence homology, when considered in toto, can all recruit and activate the two highly conserved beta-arrestin proteins as part of their signaling/desensitization process. Although the serine and threonine residues that form GPCR kinase phosphorylation sites are common beta-arrestin-associated receptor determinants regulating receptor desensitization and internalization, the agonist-activated conformation of a GPCR probably reveals the most fundamental determinant mediating the GPCR and arrestin interaction. Here we identified a beta-arrestin binding determinant common to the rhodopsin family GPCRs formed from the proximal 10 residues of the second intracellular loop. We demonstrated by both gain and loss of function studies for the serotonin 2C, beta2-adrenergic, alpha2a)adrenergic, and neuropeptide Y type 2 receptors that the highly conserved amino acids, proline and alanine, naturally occurring in rhodopsin family receptors six residues distal to the highly conserved second loop DRY motif regulate beta-arrestin binding and beta-arrestin-mediated internalization. In particular, as demonstrated for the beta2 AR, this occurs independently of changes in GPCR kinase phosphorylation. These results suggest that a GPCR conformation directed by the second intracellular loop, likely using the loop itself as a binding patch, may function as a switch for transitioning beta-arrestin from its inactive form to its active receptor-binding state.

Molecular mimicry of the antigen receptor signalling motif by transmembrane proteins of the Epstein-Barr virus and the bovine leukaemia virus

BACKGROUND

Many transmembrane proteins of eukaryotic cells have only a short cytoplasmic tail of 10 - 100 amino acids, which has no obvious catalytic function. These tails are thought to be involved either in signal transduction or in the association of transmembrane proteins with the cytoskeleton. We have previously identified, in the cytoplasmic tails of components of B and T lymphocyte antigen receptors, an amino-acid motif that is required for signalling. The same motif is also found in the cytoplasmic tails of two viral proteins: the latent membrane protein, LMP2A, of Epstein Barr virus and the envelope protein, gp30, of bovine leukaemia virus. Interestingly, both viruses can activate infected B lymphocytes to proliferate, as does signalling by the B-cell receptor.

RESULTS

In this study, we show that the cytoplasmic tails of the two viral proteins, and the cytoplasmic tail of the B-cell receptor immunoglobulin-alpha chain, when linked to CD8 in chimeric transmembrane proteins, can transduce signals in B cells. Cross-linking of these chimeric receptors activates B-cell protein tyrosine kinases and results in calcium mobilization. Furthermore, these cytoplasmic sequences are also protein tyrosine kinase substrates and may interact with cytosolic proteins carrying SH2 protein-protein interaction domains.

CONCLUSION

Our findings suggest that viral transmembrane proteins can mimic the antigen-induced stimulation of the B-cell antigen receptor and thus can influence the activation and/or survival of infected B lymphocytes.

G protein-coupled receptor kinase regulates dopamine D3 receptor signaling by modulating the stability of a receptor-filamin-beta-arrestin complex. A case of autoreceptor regulation

In addition to its postsynaptic role, the dopamine D3 receptor (D3R) serves as a presynaptic autoreceptor, where it provides continuous feedback regulation of dopamine release at nerve terminals for processes as diverse as emotional tone and locomotion. D3R signaling ability is supported by an association with filamin (actin-binding protein 280), which localizes the receptor with G proteins in plasma membrane lipid rafts but is not appreciably antagonized in a classical sense by the ligand-mediated activation of G protein-coupled receptor kinases (GRKs) and beta-arrestins. In this study, we investigate GRK-mediated regulation of D3R.filamin complex stability and its effect on D3R.G protein signaling potential. Studies in HEK-293 cells show that in the absence of agonist the D3R immunoprecipitates in a complex containing both filamin A and beta-arrestin2. Moreover, the filamin directly interacts with beta-arrestin2 as assessed by immunoprecipitation and yeast two-hybrid studies. With reductions in basal GRK2/3 activity, an increase in the basal association of filamin A and beta-arrestin2 with D3R is observed. Conversely, increases in the basal GRK2/3 activity result in a reduction in the interaction between the D3R and filamin but a relative increase in the agonist-mediated interaction between beta-arrestin2 and the D3R. Our data suggest that the D3R, filamin A, and beta-arrestin form a signaling complex that is destabilized by agonist- or expression-mediated increases in GRK2/3 activity. These findings provide a novel GRK-based mechanism for regulating D3R signaling potential and provide insight for interpreting D3R autoreceptor behavior.

Differential regulation of phospholipase Cgamma subtypes through FcepsilonRI, high affinity IgE receptor

The high affinity IgE receptor (FcepsilonRI) usually exists as a tetramer composed of alphabetagamma2 subunits. The COOH-tail of beta and gamma subunits contains consensus sequence termed 'immunoreceptor tyrosine-based activation motif' (ITAM). Tyrosine phosphorylated ITAM interacts with signaling proteins that contain the Src homology domain, forming a main amplifying and signaling route for FcepsilonRI. Unlike the COOH-tail, the functional role of NH(2)-tail of beta subunit in the signaling of FcepsilonRI is not clear because it lacks the ITAM sequences. To study the roles of NH(2)-tail of beta subunit, the cDNA library of RBL-2H3 cells was screened by yeast two-hybrid assay, and the NH(2)-tail of the beta subunit was found to interact with phospholipase Cgamma2 (PLCgamma2) but not with PLCgamma1. Since both PLCgamma1 and PLCgamma2 are expressed in RBL-2H3 cells and they possess identical cellular functions, the functional meaning of the protein-protein interaction between PLCgamma2 and NH(2)-tail of beta subunit was studied by comparing the regulatory pathways that control the FcepsilonRI-mediated tyrosine phosphorylation of the two enzymes. Our study shows that PI3-kinase and PMA-sensitive PKCs were required exclusively for the FcepsilonRI-mediated tyrosine phosphorylation of PLCgamma1. Also the FcepsilonRI-mediated tyrosine phosphorylation of PLCgamma1 was more sensitive to the inhibitors of Src and Syk kinases. These results therefore suggest that PLCgamma1 is involved in dynamic regulation of protein kinase C activity and inositol triphosphate levels in response to cellular needs. In contrast, PLCgamma2, through continuous interaction with the NH(2)-tail of beta subunit, co-localizes with FcepsilonRI in the same signaling domain, and maintains the basal cellular PLC activity.

Molecular mechanisms of inhibitory activities of tanshinones on Lipopolysaccharide-lnduced nitric oxide generation in RAW 264.7 cells

The effects of four tanshinones isolated from Tanshen (the root of Salvia miltiorrhiza Bunge, Labiatae) were tested for their inhibition of nitric oxide production in macrophage cells, and the underlying molecular mechanisms studied. Of the four tanshinones used, 15, 16-dihydrotanshinone-I, tanshinone-IIA and cryptotanshinone, but not tanshinone I, demonstrated significant inhibition of the LPS-induced nitric oxide production in RAW 264.7 cells, with calculated IC50 values of 5, 8, and 1.5 microM, respectively. Tanshinones exerted inhibitory activities on the LPS-induced nitric oxide production only when applied concurrently with LPS, and tanshinone-IIA and cryptotanshinone were found to inhibit LPS-induced NF-kappaB mobilization and extracellular-regulated kinase (ERK) activation, respectively. These results suggest that tanshinones inhibit LPS-induced nitric oxide generation by interfering with the initial stage of LPS-induced expression of certain genes. NF-kappaB and ERK could be the molecular targets for tanshinones for the inhibition of LPS-induced nitric oxide production in macrophage cells.

Changes in visual and auditory response time during conscious sedation with propofol

BACKGROUND

Using a push-button device, we investigated whether visual or auditory response time would increase with increasing sedation, and assessed the responsiveness score of the Observer's Assessment of Alertness/Sedation (OAA/S) scale at the point of first loss of response to visual or auditory stimulation.

METHODS

In experiment 1 we applied visual and auditory stimulation to 19 patients as the propofol target plasma concentration (CPT) was increased to determine whether the visual or auditory response would be lost first. Thirty patients were each then infused with propofol, starting at a CPT of 0.3 microg ml(-1) and increasing by increments of 0.2 microg ml(-1), during which visual (experiment 2) or auditory (experiment 3) stimulation was applied when the effect-site concentration (CE) of propofol reached CPT. Visual response time (VRT), auditory response time (ART), CE and total amounts of propofol, and OAA/S score at the first loss of visual/auditory response were measured.

RESULTS

Visual response disappeared earlier than auditory response in 84.2% of the patients. Visual response time and ART were linearly prolonged as the CE of propofol increased. The CE and total amounts of propofol at the first loss of visual response were 1.2 +/- 0.4 microg ml(-1) and 57.9 +/- 16.7 mg, compared with 1.4 +/- 0.5 microg ml(-1) and 71.6 +/- 26.1 mg, respectively, at the first loss of auditory response. The median (range) OAA/S scores at the first loss of visual and auditory response were 4 (3-4) and 3 (2-4), respectively.

CONCLUSION

VRT and ART were linearly prolonged with increasing sedation. Visual response may be useful in monitoring conscious sedation.

Perivascular–submandibular lymph node metastasis in squamous cell carcinoma of the tongue and floor of mouth

AIMS

The goal of this study was to investigate the incidence of occult metastasis in perivascular lymph node and nodal recurrence in these nodal pads in squamous cell carcinoma (SCC) of the tongue and floor of mouth.

METHODS

We performed a prospective analysis of the incidence of an occult metastasis in the perivascular lymph nodes in 55 patients (41 with an oral tongue carcinoma and 14 with a mouth floor carcinoma) who underwent an elective supraomohyoid neck dissection (SOHND) for SCC of the tongue and floor of mouth, from 1997 to 2002. 99 SOHND procedures were performed as follows: 72 in tongue carcinomas and 27 in the mouth floor carcinomas.

RESULT

Clinically occult, but pathologically positive perivascular lymph nodes occurred in four of 72 of the tongue carcinomas and two of 27 of the mouth floor carcinomas. The incidence of the regional recurrence at level I was three of 45.

CONCLUSIONS

This preliminary report reveals a small incidence of perivascular lymph-node metastases and the infrequent nodal recurrence in this area after SOHND in early-staged tongue and floor of mouth SCC.

Comparative Studies of Molecular Mechanisms of Dopamine D2 and D3 Receptors for the Activation of Extracellular Signal-regulated Kinase

Dopamine D(2) and D(3) receptors (D(2)R/D(3)R), which have similar structural architecture as well as functional similarities, are expressed in the same brain dopaminergic neurons. It is intriguing that two receptor proteins with virtually the same functional roles are expressed in the same neuron. Recently we have shown that D(2)R and D(3)R possess different regulatory processes including intracellular trafficking properties, which implies that they might employ different signaling mechanisms for regulation of the same cellular processes. Here we studied the signaling pathways of ERK activation mediated by D(2)R and D(3)R in HEK-293 cells and corroborated them with concomitant studies in COS-7 cells and C6 cells. Our results show that Src, phosphatidylinositol 3-kinase, and atypical protein kinase C were commonly involved in D(2)R-/D(3)R-mediated ERK activation. However, beta-arrestin and sequestration of D(2)R/D(3)R were found not to be involved. ERK activations mediated by D(3)R, but not D(2)R, were blocked by betaARK-CT, AG1478 epidermal growth factor receptor (EGFR) inhibitor, and by dominant negative mutants of Ras and Raf, suggesting the involvement of the Gbetagamma(i) pathway. The alpha-subunit of G(o) (Galpha(o)) was able to couple with D(3)R to mediate ERK activation. We conclude that D(3)R mainly utilizes the betagamma pathway of G(i) protein, which involves the transactivation of EGFR in HEK-293 cells. In contrast, the alpha-subunit of the G(i) protein plays a main role in D(2)R-mediated ERK activation. Our study suggests one example of intricate cellular regulations in the brain, that is, dopaminergic neurons could regulate ERK activity more flexibly through alternative usage of either the D(2)R or D(3)R pathway depending on the cellular situation.

Excavation of lead compounds that inhibit mast cell degranulation by combinatorial chemistry and activity-guided

An allergic reaction ensues after antigen binds to mast cell or basophil high affinity IgE receptor, Fc epsilonRI, resulting in degranulation of various inflammatory mediators that produce various allergic symptoms. In this study, i) we isolated the active component for the inhibition of mast cell degranulation from the extract of leaves of Castanea crenata and identified it as quercetin; ii) we established the total synthesis procedure of quercetin; iii) using quercetin as positive control, we excavated some lead compounds that possess inhibitory activities for mast cell degranulation by screening the chemical libraries of 1,3-oxazolidine derivatives prepared by solid phase combinatorial chemistry. Some of 1,3-oxazolidine compounds possessing acetyl and 3',4'-dichlorophenyl group displayed strong inhibitory activities on Fc epsilonRI-mediated mast cell degranulation, suggesting that they can be used as lead compounds for the development of anti-allergic agents.

Morphological and photoelectrochemical characterization of core-shell nanoparticle films for dye-sensitized solar cells: Zn-O type shell on SnO2 and TiO2 cores

Core-shell type nanoparticles with SnO2 and TiO2 cores and zinc oxide shells were prepared and characterized by surface sensitive techniques. The influence of the structure of the ZnO shell and the morphology ofnanoparticle films on the performance was evaluated. X-ray absorption near-edge structure and extended X-ray absorption fine structure studies show the presence of thin ZnO-like shells around the nanoparticles at low Zn levels. In the case of SnO2 cores, ZnO nanocrystals are formed at high Zn/Sn ratios (ca. 0.5). Scanning electron microscopy studies show that Zn modification of SnO2 nanoparticles changes the film morphology from a compact mesoporous structure to a less dense macroporous structure. In contrast, Zn modification of TiO2 nanoparticles has no apparent influence on film morphology. For SnO2 cores, adding ZnO improves the solar cell efficiency by increasing light scattering and dye uptake and decreasing recombination. In contrast, adding a ZnO shell to the TiO2 core decreases the cell efficiency, largely owing to a loss of photocurrent resulting from slow electron transport associated with the buildup of the ZnO surface layer.

Tanshinones inhibit mast cell degranulation by interfering with IgE receptor-mediated tyrosine phosphorylation of PLCgamma2 and MAPK

Recently we have isolated four active components from Tanshen (the root of Salvia miltiorrhiza Bunge, Labiatae) responsible for the anti-allergic activities. In this study, the molecular mechanism of action of tanshinones for the inhibition of mast cell degranulation was investigated by testing their effects on the signaling components of the high affinity IgE receptor FcepsilonRI. Activation of FcepsilonRI produced immediate tyrosine phosphorylation of Syk, mitogen-activated protein kinase extracellular signal-regulated kinase, ERK1/ERK2 (p44, p42), and phospholipase Cgamma2 (PLCgamma2). 5,16-Dihydrotanshinone-I possessed the strongest inhibitory effects on mast cell degranulation and markedly reduced FcepsilonRI-mediated tyrosine phosphorylation of ERK and PLCgamma2. This suggests that tanshinones possibly exert their anti-allergic activities by affecting FcepsilonRI-mediated tyrosine phosphorylation of ERK and PLCgamma2. Abbreviations. FcepsilonRI:high affinity IgE receptor ERK:extracellular signal regulated kinase PLC: phospholipase C

Ion-channel currents of smooth muscle cells isolated from the prostate of guinea-pig

OBJECTIVE

To characterize the voltage-activated ion-channel currents in guinea-pig prostate smooth muscle cells (GPSMCs).

MATERIALS AND METHODS

GPSMCs were isolated using collagenase, and used in a whole-cell patch clamp study.

RESULTS

When GPSMCs were dialysed with a CsCl solution all the outward K+ currents were blocked and the step-like depolarization (holding voltage -70 mV) of the cell membrane evoked inward currents that were completely blocked by nifedipine (1 micromol/L). With KCl solution, step depolarizations showed outward K+ currents composed of fast, transient outward current (Ito) and outward currents that did not inactivate. Ito was resistant to a high concentration of tetraethylammonium (TEA, 5 mmol/L) but was blocked by 4-aminopyridine (5 mmol/L). The half-activation and half-inactivation voltages of Ito were 6 mV and -58 mV, respectively. With low Ca2+ buffer (0.1 mmol/L EGTA) in the solution, there were spontaneous transient outward currents (STOCs) at depolarized membrane voltages (0 mV). STOCs were blocked by TEA (1 mmol/L) or iberiotoxin (10 nmol/L) but were insensitive to apamin (100 nmol/L).

CONCLUSION

This voltage-clamp study showed that GPSMCs have l-type Ca2+ channels and more than two types of K+ channels. The voltage- and time-dependent changes of these ion channels and their interactions might be important in forming action potentials and regulating contractility.

Yeast hydrolysate reduces body fat of dietary obese rats

The purpose of this study was to assess the antiobesity effect of the yeast hydrolysate (DNF) on the body weight, body fat and plasma lipids levels of high-fat fed rats. The weight gain of the HF (high fat diet) (162.58 +/- 6.68 g) was significantly (p < 0.05) greater than that of DNF-1, DNF-2, (high fat diet with DNF of 0.5 and 1.0 g/kg body weight, respectively) and control groups (143.19 +/- 7.33 g, 139.20 +/- 8.36 g, 130.23 +/- 8.02 g, respectively). The wet weight of the epididymal fat and the perirenal fat pads of the DNF-1, DNF-2 and control groups were reduced significantly (p < 0.05). A significant (p < 0.05) increase of HDL-cholesterol level of the DNF-2 and control groups was observed. However, there was no significant difference between DNF-1 and DNF-2. It was also found that the triacylglycerol (TG) levels decreased significantly (p < 0.05) in the DNF-2 group from that of the HF, but there was no significant (p < 0.05) difference between DNF-1 and DNF-2.

Prevention of ginsenoside-induced desensitization of Ca2+-activated Cl- current by microinjection of inositol hexakisphosphate in Xenopus laevis oocytes: involvement of GRK2 and beta-arrestin I

We demonstrated that ginsenosides, the active ingredient of Panax ginseng, enhance endogenous Ca(2+)-activated Cl(-) currents via Galpha(q/11)-phospholipase C-beta3 pathway in Xenopus laevis oocytes. Moreover, prolonged treatment of ginsenosides induced Cl(-) channel desensitization. However, the molecular mechanisms involved in ginsenoside-induced Cl(-) channel desensitization have not yet been determined precisely. To provide answers to these questions, we investigated the changes in ginsenoside-induced Cl(-) channel desensitization after intraoocyte injection of inositol hexakisphosphate (InsP(6)), which is known to bind beta-arrestins and interfere with beta-arrestin-induced receptor down-regulation, and cRNAs coding beta-arrestin I/II and G-protein receptor kinase 2 (GRK2), which is known to phosphorylate G protein-coupled receptors and attenuate agonist stimulations. When control oocytes were stimulated with ginsenosides, the second, third, and fourth responses to ginsenosides were 69.6 +/- 4.1, 9.2 +/- 2.3, and 2.6 +/- 2.2% of the first responses, respectively. Preintraoocyte injection of InsP(6) before ginsenoside treatment restored ginsenoside effect to initial response levels in a concentration-, time-, and structurally specific manner, in that inositol hexasulfate had no effect. The EC(50) was 13.9 +/- 8.7 microM. Injection of cRNA coding beta-arrestin I but not beta-arrestin II blocked InsP(6) effect on prevention of ginsenoside-induced Cl(-) channel desensitization. Injection of cRNA coding GRK2 abolished ginsenoside effect enhancing Cl(-) current. However, the GRK2-caused loss of ginsenoside effect on Cl(-) current was prevented by coinjection of GRK2 with GRK2-K220R, a dominant-negative mutant of GRK. These results indicate that ginsenoside-induced Cl(-) channel desensitization is mediated via activation of GRK2 and beta-arrestin I.

The role of phosphorylation in D1 dopamine receptor desensitization: evidence for a novel mechanism of arrestin association

Homologous desensitization of D(1) dopamine receptors is thought to occur through their phosphorylation leading to arrestin association which interdicts G protein coupling. In order to identify the relevant domains of receptor phosphorylation, and to determine how this leads to arrestin association, we created a series of mutated D(1) receptor constructs. In one mutant, all of the serine/threonine residues within the 3rd cytoplasmic domain were altered (3rdTOT). A second construct was created in which only three of these serines (serines 256, 258, and 259) were mutated (3rd234). We also created four truncation mutants of the carboxyl terminus (T347, T369, T394, and T404). All of these constructs were comparable with the wild-type receptor with respect to expression and adenylyl cyclase activation. In contrast, both of the 3rd loop mutants exhibited attenuated agonist-induced receptor phosphorylation that was correlated with an impaired desensitization response. Sequential truncation of the carboxyl terminus of the receptor resulted in a sequential loss of agonist-induced phosphorylation. No phosphorylation was observed with the most severely truncated T347 mutant. Surprisingly, all of the truncated receptors exhibited normal desensitization. The ability of the receptor constructs to promote arrestin association was evaluated using arrestin-green fluorescent protein translocation assays and confocal fluorescence microscopy. The 3rd234 mutant receptor was impaired in its ability to induce arrrestin translocation, whereas the T347 mutant was comparable with wild type. Our data suggest a model in which arrestin directly associates with the activated 3rd cytoplasmic domain in an agonist-dependent fashion; however, under basal conditions, this is sterically prevented by the carboxyl terminus of the receptor. Receptor activation promotes the sequential phosphorylation of residues, first within the carboxyl terminus and then the 3rd cytoplasmic loop, thereby dissociating these domains and allowing arrestin to bind to the activated 3rd loop. Thus, the role of receptor phosphorylation is to allow access of arrestin to its receptor binding domain rather than to create an arrestin binding site per se.

Direct and biochemical interaction between dopamine D3 receptor and elongation factor-1Bbetagamma

Novel signaling components of dopamine D3 receptor (D3R) were searched using yeast two-hybrid system, and the gamma subunit of elongation Factor-1B (eEF1Bgamma) was found to interact with D3R. This interaction was observed specifically between eEF1Bgamma and D3R but not with D2R or D4R. Immunocytochemical studies showed that D3R and eEF1Bgamma form clusters on the plasma membrane and their co-localization was evident in these clusters. The beta subunit of eEF1B (eEF1Bbeta), which forms a tight complex with eEF1Bgamma, was phosphorylated on serine residues in response to the stimulation of D3R. Phosphorylation of eEF1Bbeta was insensitive to pertussis toxin or wortmannin, however, stimulation of cellular protein kinase C (PKC) directly phosphorylated eEF1Bbeta and depletion of PKC abolished D3R-mediated phosphorylation of eEF1Bbeta. These results suggest the involvement of PKC, but not Gi/o proteins or phosphatidylinositol 3-kinase, in D3R-mediated phosphorylation of eEF1Bbeta. Stimulation of D3R did not activate PKC, but the activation of PKC resulted in the phosphorylation of D3R. These results show that PKC has a permissive role for the D3R-mediated phosphorylation of eEF1Bbeta, and suggest that PKC could modulate the mutual interaction between two protein by phosphorylating both D3R and eEF1Bbeta. Therefore, the cellular PKC level would be important for the D3R-mediated modulation of eEF1B, and for their cellular regulations such as protein synthesis or cellular proliferation.

Treadmill exercise increases cell proliferation in hippocampal dentate gyrus in alcohol-intoxicated rats

AIM

Effect of treadmill exercise on hippocampal cell proliferation under normal conditions has been well documented; however, this effect under alcohol intoxication conditions is not clarified, yet. In the present study, the effect of treadmill exercise on cell proliferation in the dentate gyrus in alcohol-intoxicated rats was investigated.

METHODS

EXPERIMENTAL DESIGN

comparative investigation on number of 5-bromo-2'-deoxyuridine (BrdU)-positive cells in the dentate gyrus 8 days after commencement.

SETTING

animal laboratory.

PARTICIPANTS

male Sprague-Dawley rats of 5 weeks in age weighing 150+/-10 g.

INTERVENTION

animals were divided into 4 groups: the control-rest group, the control-exercise group, the alcohol-treated-rest group, and the alcohol-treated-exercise group. Animals of the alcohol-treated groups were injected intraperitoneally with alcohol (2 g/kg) once a day for 3 days. All animals were injected BrdU (50 mg/kg) intraperitoneally, and rats of exercise groups were made to run on treadmill for 30 min each day for 5 days following alcohol administration.

MEASURES

mean number of BrdU-positive cells in dentate gyrus was observed via immunohistochemistry.

RESULTS

Treadmill exercise significantly increased the number of BrdU-positive cells in the dentate gyrus. Also, treatment with alcohol for 3 days inhibited cell proliferation and treadmill exercise alleviated alcohol-induced inhibition of new cell formation.

CONCLUSION

These results suggest the possibility that treadmill exercise may help in improvement following alcohol-induced brain damage.

Delayed-onset pineal abscess following transsphenoidal surgery for pituitary adenoma: a case report

A 41-year-old woman suffered fever, speech disturbance and confusion four months after transsphenoidal surgery for pituitary macroadenoma. Meanwhile, the patient had been well except for transient asymptomatic postoperative pneumocephalus without cerebrospinal fluid (CSF) rhinorrhoea. Brain computed tomographic scan revealed a peripherally enhancing pineal abscess which superimposed on a preexisting pineal cyst. CSF findings showed elevated leukocyte count and positive bacterial culture. Three weeks of intensive antibiotic therapy and surgical evacuation of the pineal abscess ensued. The patient showed restricted postoperative recovery with moderate hypothalamic dysfunction. A unique case of delayed-onset postoperative pineal abscess which complicates the preexisting asymptomatic pineal cyst is presented and the possible explanation for this is speculated with review of the available literatures.

Pharmacological activities of stromata of Cordyceps scarabaecola

The chemical components of freeze-dried stromata from Cordyceps scarabaecola were examined. The stromata consisted of crude carbohydrates (55.1%) and crude proteins (14.2%). The stromata were also composed of a low content of crude ash (6.6%) and fat (1.5%). The composition of the carbohydrate in the stromata included a large quantity of glucose (46.6%), mannose (35.4%) and galactose (18.0%). The acidic amino acids such as glutamic acid (32.1 mg/g) and aspartic acid (24.7 mg/g) were present in a large quantity. The extracts of stromata did not reveal any inhibitory activity for AChE in vitro. It was observed that a hot-water extract (HW) of the stromata contributed significantly to the anticoagulant activity (60 s coagulating time) and anticomplementary activity (62% of ITCH50 value). The MeOH-soluble fraction (M) from the freeze-dried stromata inhibited TPA-induced O2- generation as effectively as the positive control, genistine 27%. The hot-water extract (HW) showed the most potent intestinal immune system modulation activity and the MeOH-soluble fraction (M) had intermediate activity.

Anti-stress and anti-fatigue effect of fermented rice bran

The anti-stress and anti-fatigue effects of a hot water extract of fermented rice bran (FRB) were investigated with Saccharomyces cerevisae IFO 2346 on rats or mice. Oral administration (1 g/kg/day) of a hot water extract of FRB inhibited major changes in weight of the adrenal, thymus, spleen and thyroid, showing the anti-stress effect. A hot water extract of FRB also inhibited the increase of GPT and LDH activity, cholesterol and serum glucose levels. Administration (1 g/kg/day) for 2 weeks significantly prolonged the swimming time, resulting in an increase of the anti-fatigue effect. From these results, it can be considered that FRB has an anti-stress and anti-fatigue effect.

Effects of resveratrol-related hydroxystilbenes on the nitric oxide production in macrophage cells: structural requirements and mechanism of action

NF-kappaB that plays an important role in iNOS expression is one of the targets of various potential anti-inflammatory agents including resveratrol. Resveratrol contains a structural similarity with estrogen, and there has been speculation about resveratrol as estrogen agonist. In this study, the mechanism and structural requirements of resveratrol and related hydroxystilbenes for the inhibition of LPS-induced nitric oxide production were studied in macrophage cells (RAW 264.7 and J774) by comparing its effect on LPS-induced NF-kappaB translocation and nitric oxide production, and by considering the possibility of involvement of an estrogen receptor. LPS-induced nitric oxide production was inhibited only when cells were treated with resveratrol prior to stimulation with LPS, suggesting that resveratrol does not affect the enzyme itself. A higher concentration of resveratrol than needed for the inhibition of nitric oxide production was required for the inhibition of NF-kappaB mobilization or iNOS expression. Estrogen and diethylstilbesterol, an estrogen agonist, caused only weak inhibition of nitric oxide production, and the effects of resveratrol were not noticeably blocked by ICI-182780, an estrogen antagonist. Structure-activity analysis of resveratrol and nine hydroxystilbenes suggests that the structural balance between oxygen functional groups on the benzene rings is important for their activity. Our results suggest that resveratrol might act on other cellular targets as well as NF-kappaB at the initial stage of gene expression. Unique structural features of hydroxystilbenes are needed for suppression of nitric oxide production and it is unlikely that estrogen receptor is involved in it.