Streptozotocin induces neurite outgrowth via PI3K-Akt and glycogen synthase kinase 3β in Neuro2a cells

Streptozotocin (STZ), a naturally occurring chemical, is toxic to the various kinds of cells such as insulin-producing beta cells. However, the beneficial effect of STZ on neuronal cells such as neurite outgrowth-inducing activity has been unknown. In this study, we examined the effect of STZ on neurite outgrowth in mouse neuronal Neuro2a cells. STZ (0.01 mM~5 mM) exerted remarkable neurite outgrowth-inducing activity in Neuro2a cells in a concentration dependent manner. STZ also had the same neurite outgrowth-inducing activity as that of retinoic acid (RA), which is well known neurite outgrowth inducer. As with the result of RA treatment, STZ administration increased MAP2-positive cells. The MAP2-positive cells reflect neurite outgrowth-induced cells. STZ (0.01 mM~5 mM) did not induce cell death, but significantly decreased cell proliferation. The serine/threonine kinase Akt, a downstream target of phosphatidylinositol-3 kinase (PI3K), was transiently phosphorylated at Ser473 and at Thr303 by STZ (5 mM) administration. Glycogen synthase kinase 3β (GSK3β), which has been reported to be inactivated by Akt, was also transiently phosphorylated at Ser9 by STZ (5 mM) administration. In addition, a blocker of PI3K, LY294002 (10 μM), significantly attenuated STZ-induced neurite outgrowth. These results suggest that STZ induces neurite outgrowth via activation of PI3K-Akt signaling pathway and GSK3β inhibition.

Pramlintide Antagonizes Beta Amyloid (Aβ)- and Human Amylin-Induced Depression of Hippocampal Long-Term Potentiation

Accumulation of amyloid-β peptide (Aβ) is a pathological hallmark of Alzheimer's disease (AD). We have previously demonstrated that electrophysiological and neurotoxic effects of Aβ and human amylin are expressed via the amylin receptor. Recently, pramlintide, a synthetic analog of amylin, has been reported to improve cognitive function in transgenic AD mouse models. In this study, we examined the effects of pramlintide on Aβ_1-42 and human amylin-evoked depression of long-term potentiation (LTP) at Schaeffer collateral-CA1 hippocampal synapses. In mouse hippocampal brain slices, field excitatory postsynaptic potentials (fEPSPs) were recorded from the stratum radiatum layer of the CA1 area in response to electrical stimulation of Schaeffer collateral afferents and LTP induced by 3-theta-burst stimulation (TBS) protocol. Aβ_1-42 (50 nM) and human amylin (50 nM), but not Aβ_42-1 (50 nM), depressed LTP. Pre-application of pramlintide (250 nM) blocked Aβ- and human amylin-induced reduction of LTP without affecting baseline transmission or LTP. We also examined the effects of pramlintide on LTP in transgenic mice (TgCRND8) that over-express amyloid precursor protein. In contrast to wild-type controls, where robust LTP was observed, 10- to 12-month-old TgCRND8 mice show blunted LTP. In TgCRND8 mice, basal LTP is enhanced by application of pramlintide. Our data indicate that pramlintide acts as a functional amylin receptor antagonist to reverse the effects of Aβ_1-42 and human amylin on LTP and also increases LTP in transgenic mice that demonstrate increased ambient brain amyloid levels. Amylin receptor antagonists may thus serve as potentially useful therapeutic agents in treatment of AD.

Effects of CO2 and osmolality on hybridoma cells: growth, metabolism and monoclonal antibody production

CO2 partial pressure (pCO2) in industrial cell culture reactors may reach 150-200 mm Hg, which can significantly inhibit cell growth and recombinant protein production. Due to equilibrium with bicarbonate, increased pCO2 at constant pH results in a proportional increase in osmolality. Hybridoma AB2-143.2 cell growth rate decreased with increasing pCO2 in well-plate culture, with a 45% decrease at 195 mm Hg with partial osmolality compensation (to 361 mOsm kg- 1). Inhibition was more extensive without osmolality compensation, with a 63% decrease in growth rate at 195 mm Hg and 415 mOsm kg-1. Also, the hybridoma death rate increased with increasing pCO2, with 31- and 64-fold increases at 250 mm Hg pCO2 for 401 and 469 mOsm kg- 1, respectively. The specific glucose consumption and lactate production rates were 40-50% lower at 140 mm Hg pCO2. However, there was little further inhibition of glycolysis at higher pCO2. The specific antibody production rate was not significantly affected by pCO2 or osmolality within the range tested. Hybridomas were also exposed to elevated pCO2 in continuous culture. The viable cell density decreased by 25-40% at 140 mm Hg. In contrast to the well-plate cultures, the death rate was lower at the new steady state at 140 mm Hg. This was probably due to higher residual nutrient and lower byproduct levels at the lower cell density (at the same dilution rate), and was associated with increased cell-specific glucose and oxygen uptake. Thus, the apparent effects of pCO2 may vary with the culture system.

Molecular analysis of two enzyme genes, HPRT1 and PRPS1, causing X-linked inborn errors of purine metabolism

Inherited mutation of hypoxanthine guanine phosphoribosyltransferase (HPRT) gives rise to Lesch-Nyhan syndrome or HPRT-related gout. On the other hand, PRPS1 mutations cause PRPP synthetase superactivity associated with hyperuricemia and gout, sometimes including neurodevelopmental abnormalities. We have identified two mutations in two Lesch-Nyhan families after our last report. One of them, a new single nucleotide substitution (130G>T) resulting in a missense mutation D44Y was detected in exon 2 of HPRT1. RT-PCR amplification showed not only a cDNA fragment with normal size, but also a small amount of shorter fragment skipping exons 2 and 3. The other missense mutation F74L (222C > A) was detected in a Japanese patient but has been reported previously in European families. In four hyperuricemic patients with mild neurological abnormality, no mutations responsible for partial HPRT deficiency were identified in HPRT1. In these four patients, we also performed molecular analysis of PRPS1, but no mutations in PRPP synthetase were found.

Glucagon-like peptide-1 (GLP-1) protects against methylglyoxal-induced PC12 cell apoptosis through the PI3K/Akt/mTOR/GCLc/redox signaling pathway

Patients with long-standing diabetes commonly develop diabetic encephalopathy, which is characterized by cognitive impairment and dementia. Oxidative stress-induced neuronal cell apoptosis is a contributing factor. Glucagon-like peptide (GLP)-1 has recently become an attractive treatment modality for patients with diabetes. It also readily enters the brain, prevents neuronal cell apoptosis, and improves the cognitive impairment characteristic of Alzheimer's disease. Therefore, we investigated whether GLP-1 could protect against oxidative stress-induced neuronal cell apoptosis in pheochromocytoma (PC12) cells. PC12 cells were exposed to 1 mM methylglyoxal (MG) or MG plus 3.30 microg/ml GLP-1. Cell apoptosis, expression and phosphorylation of phosphatidylinositol-3 kinase/Akt/mammalian target of rapamycin/gamma-glutamylcysteine ligase catalytic subunit (GCLc), and redox balance were then determined. The data showed that MG induced PC12 apoptosis in accordance with the redox (glutathione (GSH) and GSH/glutathione disulfide [GSSG]) imbalance. GLP-1 protected against this MG-induced apoptosis, which corresponded to the phosphorylation of PI3K, Akt, and mTOR, as well as the upregulation of GCLc and the restoration of the redox imbalance. Inhibitors of PI3K (LY294002), Akt (Akt-I), and mTOR (rapamycin) reduced the GLP-1-induced GCLc upregulation and its protection against MG-induced PC12 apoptosis. The GLP-1-induced redox restoration was also attenuated by rapamycin. In conclusion, the neuroprotective effect of GLP-1 is due to an enhancement of PI3K/Akt/mTOR/GCLc/redox signaling.

A molecular chaperone inducer protects neurons from ER stress

The endoplasmic reticulum (ER) stress response is a defense system for dealing with the accumulation of unfolded proteins in the ER lumen. Recent reports have shown that ER stress is involved in the pathology of some neurodegenerative diseases and cerebral ischemia. In a screen for compounds that induce the ER-mediated chaperone BiP (immunoglobulin heavy-chain binding protein)/GRP78 (78 kDa glucose-regulated protein), we identified BiP inducer X (BIX). BIX preferentially induced BiP with slight inductions of GRP94 (94 kDa glucose-regulated protein), calreticulin, and C/EBP homologous protein. The induction of BiP mRNA by BIX was mediated by activation of ER stress response elements upstream of the BiP gene, through the ATF6 (activating transcription factor 6) pathway. Pretreatment of neuroblastoma cells with BIX reduced cell death induced by ER stress. Intracerebroventricular pretreatment with BIX reduced the area of infarction due to focal cerebral ischemia in mice. In the penumbra of BIX-treated mice, ER stress-induced apoptosis was suppressed, leading to a reduction in the number of apoptotic cells. Considering these results together, it appears that BIX induces BiP to prevent neuronal death by ER stress, suggesting that it may be a potential therapeutic agent for cerebral diseases caused by ER stress.

Natural killer cell-mediated ablation of metastatic liver tumors by hydrodynamic injection of IFNalpha gene to mice

Interferon (IFN) alpha is a pleiotropic cytokine acting as an antiviral substance, cell growth inhibitor and immunomodulator. To evaluate the therapeutic efficacy and mechanisms of IFNalpha on hepatic metastasis of tumor cells, we hydrodynamically injected naked plasmid DNA encoding IFNalpha1 (pCMV-IFNa1) into Balb/cA mice having 2 days hepatic metastasis of CT-26 cells. Single injection of pCMV-IFNa1 efficiently enhanced the natural killer (NK) activity of hepatic mononuclear cells, induced production of IFNgamma in serum and led to complete rejection of tumors in the liver. Mice protected from hepatic metastasis by IFNalpha therapy displayed a tumor-specific cytotoxic T cell response and were resistant to subcutaneous challenge of CT-26 cells. NK cells were critically required for IFNalpha-mediated rejection of hepatic metastasis, because their depletion by injecting anti-asialo GM1 antibody completely abolished the antimetastatic effect. To find whether NK cells are directly activated by IFNalpha and are sufficient for the antimetastatic effect, the responses to IFNalpha were examined in SCID mice lacking T cells, B cells and NKT cells. IFNalpha completely rejected hepatic metastasis in SCID mice and efficiently activated SCID mononuclear cells, as evidenced by activation of STAT1 and a variety of genes, such as MHC class I, granzyme B, tumor necrosis factor-related apoptosis-inducing ligand and IFNgamma, and also enhanced Yac1 lytic ability. Study of IFNgamma knockout mice revealed that IFNgamma was not necessary for IFNalpha-mediated NK cell activation and metastasis protection. In conclusion, IFNalpha efficiently activates both innate and adaptive immune responses, but NK cells are critically required and sufficient for IFNalpha-mediated initial rejection of hepatic metastasis of microdisseminated tumors.

Plasma protein S activity correlates with protein S genotype but is not sensitive to identify K196E mutant carriers

BACKGROUND

Protein S (PS) is an anticoagulant protein that functions as a cofactor for activated protein C (APC), and congenital PS deficiency is a well-known risk factor for the development of deep vein thrombosis (DVT). Recently, we and others identified the K196E missense mutation in the second epidermal growth factor-like domain of PS as a genetic risk factor for DVT in the Japanese population. The incidence of this mutation is high in the Japanese population.

OBJECTIVES

In the present study, we investigated the relationship between plasma PS activity and the presence of the K196E mutation.

PATIENTS AND METHODS

We measured PS activity as a cofactor activity for APC in 1,862 Japanese individuals and determined the PS K196E genotype in this population.

RESULTS

Individuals heterozygous for the mutant E-allele had lower plasma PS activity than wildtype subjects (mean +/- SD, 71.9 +/- 17.6%, n = 34 vs. 87.9 +/- 19.8%, n = 1,828, P < 0.0001). However, the PS activity of several heterozygous individuals (n = 8) was greater than the population average. In contrast, multiple wildtype subjects (n = 26) had PS activity less than 2 SD below the population mean, indicating that other genetic or environmental factors affect PS activity.

CONCLUSIONS

Plasma PS activity itself is not suitable for identifying PS 196E carriers and other methods are required for carrier detection.

Clinical features of postoperative cerebral venous infarction

There is a potential risk of sacrificing the cortical vein during neurosurgical operations, particularly in the interhemispheric or subtemporal approach. An impaired cortical vein might cause cerebral venous circulatory disturbances (CVCDs) resulting in venous infarction. In this article, we have reviewed the management and results of eight cases with symptomatic postoperative venous infarction. We have encountered eight cases with symptomatic postoperative venous infarction (0.3%) during the past 5 years. The series is composed of 3 males and 5 females, with ages that ranged from 43 to 76 years (mean age of 58.1 years), and consisted of five brain tumors, one cavernoma, one dural AVF, and one trigeminal neuralgia. Initial symptoms occurred intra-operatively in two, on 0 day after the operation in one, 1 day in three, 3 days in one, and 4 days in one case. The symptoms were intra-operative brain edema in two cases, disorientation in one, cerebellar signs in one, hemiparesis in one, aphasia in two, and headache in one case. Two cases required surgical intervention. The results were a good outcome in 6 and a fair outcome in 2 cases. In conclusion, there are two types of postoperative venous infarction; severe onset (severe type) and gradual onset (mild type). The former needs immediate treatment from the intra-operative period onward, and the prevention of the ongoing venous thrombosis is essential in the latter.

Vascular Endothelial Growth Factor Antagonist Reduces Brain Edema Formation and Venous Infarction

Background and Purpose— Cerebral venous ischemia often induces severe brain edema. Vascular endothelial growth factor (VEGF), which induces angiogenesis, is also known as vascular permeability (VP) factor. The present study was undertaken to investigate whether the inhibition of VEGF could reduce brain edema formation and cerebral venous infarction (CVI) in a rat 2-vein occlusion (2-VO) model.

Methods— We used 2-VO model in which 2 adjacent cortical veins were photochemically occluded. Male Wistar rats (n=25) were divided into 2 groups: one group was treated with a VEGF antagonist (antagonist group, n=10) and the second group was treated with phosphate-buffered solution (PBS) (PBS group, n=15). VEGF antagonist or PBS was injected intraperitoneally immediately after 2-VO. The developing ischemic infarct was evaluated by magnetic resonance imaging (MRI) and histology 24 hours after occlusion.

Results— VEGF expression was observed in the cytoplasm of neurons exclusively in the area of vasogenic edema that was shown as a high-intensity area in the apparent diffusion coefficient of water map. Ischemic volumes calculated from each MR images, which are related to infarction and/or vasogenic edema, respectively, were significantly smaller in the antagonist group as compared with the PBS group ( P <0.05)

Conclusions— Our study is the first to provide evidence that the inhibition of VEGF attenuates VP and reduces CVI in the acute stage. Although VEGF is a significant angiogenesis factor, we concluded that the inhibition of VEGF might be a new therapy for both brain edema formation and CVI.

Renal organs of cephalopods: a habitat for dicyemids and chromidinids

The renal organs of 32 species of cephalopods (renal appendage of all cephalopods, and renal and pancreatic appendages in decapods) were examined for parasite fauna and for histological comparison. Two phylogenetically distant organisms, dicyemid mesozoans and chromidinid ciliates, were found in 20 cephalopod species. Most benthic cephalopods (octopus and cuttlefish) were infected with dicyemids. Two pelagic cephalopod species, Sepioteuthis lessoniana and Todarodes pacificus, also harbored dicyemids. Chromidinid ciliates were found only in decapods (squid and cuttlefish). One dicyemid species was found in branchial heart appendages of Rossia pacifica. Dicyemids and chromidinids occasionally occurred simultaneously in Euprymna morsei, Sepia kobiensis, S. peterseni, and T. pacificus. The small-sized cephalopod species, Idiosepius paradoxus and Octopus parvus, harbored no parasites. Comparative histology revealed that the external surface of renal organs varies morphologically in various cephalopod species. The small-sized cephalopod species have a simple external surface. In contrast, the medium- to large-sized cephalopod species have a complex external surface. In the medium- to large-sized cephalopod species, their juveniles have a simple external surface of the renal organs. The external surface subsequently becomes complicated as they grow. Dicyemids and chromidinids attach their heads to epithelia or insert their heads into folds of renal appendages, pancreatic appendages, and branchial heart appendages. The rugged and convoluted external surface provides a foothold for dicyemids and chromidinids with a conical head. They apparently do not harm these tissues of their host cephalopods.

Cis-acting effect of the IL1B C−31T polymorphism on IL-1β mRNA expression

Since the effect of IL1B polymorphisms on IL-1beta production is still controversial, we selected two polymorphisms to test their cis-acting effect on IL-1beta mRNA expression by means of the allele-specific transcript quantification and the haplotype analysis. As for the C-31T polymorphism, we found that expression of the -31T allele was 2.2 times of the -31C allele. This higher transcription efficiency may correspond to the fact that C-31T is located in a TATA box. The other polymorphism, C+3954T, did not alter the levels of transcription. The use of the allele-specific transcript quantification enables us to exclude trans-acting effects of polymorphisms on the gene expression and contributes to understanding the roles of the IL1B polymorphisms in susceptibility to multifactorial diseases.

Syringomyelia caused by cervical spondylosis

Syringomyelia is generally associated with Chiari type malformations, spinal tumors, or spinal trauma. Cervical spondylosis is only rarely involved. We here present a case of a 64-year-old woman with severe radicular pain in the right arm and the syringomyelic syndrome. Lateral radiographs of the cervical spine demonstrated spondylotic change at the C4/5 and C6/7 levels, and instability at C4/5. Dynamic magnetic resonance (MR) imaging revealed the spinal cord to be compressed at C5 and C6 with the body in extension, and the syrinx extended from C2 to the Th3 level on sagittal images. It was reduced remarkably after anterior decompression and stabilization at C4/5 and C6/7, and her symptoms also improved after surgery. We concluded that the syrinx in this case might have developed due to craniospinal pressure dissociation caused by intermittent spinal cord compression.

The SDF1-G801A polymorphism is not associated with SDF1 gene expression in Epstein-Barr virus-transformed lymphoblastoid cells

The effects of the SDF1-3'A on AIDS progression have been attributed to the altered amount of stromal cell-derived factor 1 (SDF-1). However, the contribution of the SDF1-G801A polymorphism to SDF-1 expression is still unclear. In contrast to fresh peripheral blood mononuclear cells (PBMCs), Epstein-Barr virus (EBV)-transformed lymphoblastoid cell lines (LCLs) express the SDF-1 mRNA. Using EBV-transformed LCLs from 42 individuals with different genotypes, we investigated the SDF-1 mRNA levels and methylation status in the SDF1 gene. Both in PBMCs and in EBV-transformed LCLs, CpG dinucleotides in the 5' region of the SDF1 gene were unmethylated. As for the 3' untranslated region (3'UTR), by contrast, CpG dinucleotides were methylated in PBMCs, whereas site-specific demethylation around the polymorphic site was detected in EBV-transformed LCLs. The levels of the demethylation were correlated with the SDF-1 mRNA levels. However, the genotype for the SDF1-G801A polymorphism did not significantly alter the SDF-1 mRNA levels. The allele preferences in transcription and methylation were also absent in the heterozygous cells. In conclusion, this study suggested a contribution of site-specific demethylation in the 3'UTR to the SDF1 gene expression, but did not show any evidence for the contribution of the SDF1-G801A polymorphism to the amount of the SDF-1 mRNA.

Distribution of OL-protocadherin protein in correlation with specific neural compartments and local circuits in the postnatal mouse brain

OL-protocadherin (OL-pc) is a cell adhesion molecule that belongs to the cadherin superfamily. A previous study showed that expression of OL-pc mRNA was specific to certain brain nuclei including those of the olfactory and limbic systems, thus suggesting its involvement in neural circuit formation. Here, we examined the distribution of OL-pc protein in the postnatal mouse brain by immunohistochemistry to confirm the possibility of such a role. The results showed that the protein could be mapped to many brain compartments including brain nuclei and higher subdivisions as previously observed for the expression pattern of the mRNA. Sharp boundaries of the distribution were often seen in areas such as the interpedunclar nucleus, cerebellar cortex, and inferior olive. In addition, the protein was detected in some fibers that could not be examined by the previous study using in situ hybridization. For example, prominent staining was noted in the stria medularis, stria terminalis, fasciculus retroflexus, optic tract, and inferior thalamic radiation, structures that seem to connect OL-pc-positive brain regions. These OL-pc-positive brain nuclei and fiber tracts coincide with some local circuits of functional systems such as the olfactory system, nigrostriatal projection, olivo-cerebellar projection, and visual system. These results support the possibility that OL-pc is involved in the formation of specific neural compartments and circuits in the developing brain.

Expression and role of MICA and MICB in human hepatocellular carcinomas and their regulation by retinoic acid

Natural killer (NK) cells are important effector cells for the first line of defense against tumor, but the mechanisms by which they recognize and kill human hepatocellular carcinoma (HCC) remains to be elucidated. Distant MHC class I homologs MICA and MICB are recently identified human ligands for NK cell activating receptor NKG2D. In our present study, MICA or MICB transcript was detected in 6 of 10 human hepatocellular carcinoma tissues, but not in the surrounding non-cancerous tissues. Immunohistochemical analysis showed that MICA/B were expressed in the tumor cells of the cancerous tissues. Huh7 and HepG2 hepatoma cells, but not Hep3B cells, substantially expressed MICA/B on their cell surface. MICA/B expressed on hepatoma cells contributed to their NK sensitivity, because Huh7 and HepG2 were less susceptible to NK cytolysis when MAb against MICA/B was added during the cytolysis assay. Of interest is the finding that retinoic acid upregulated expression of MICA/B in Huh7 and HepG2 cells. Retinoic acid-treated hepatoma cells induced IFN gamma production from cocultured NK cells and rendered themselves more susceptible to NK cells. This was clearly dependent on upregulation of MICA/B, because both the enhanced IFN gamma production and NK cytolysis were completely abolished by MAb-mediated masking of MICA/B. These results suggest that MICA/B, expressed on a subset of human HCCs, may play an important role in their susceptibility to NK cells. Furthermore, retinoic acid can function as a modulator of MICA/B expression and thereby further activate NK cells.

Vasogenic edema and VEGF expression in a rat two-vein occlusion model

Vasogenic edema plays an important etiologic role in the pathogenesis of cerebral venous circulation disturbances (CVCDs). Since vascular endothelial growth factor (VEGF) is a major mediator in angiogenesis and vascular permeability, including induction of vasogenic edema, the present study was undertaken to investigate whether it has any relevance to CVCDs. Male Wistar rats (n = 15) were used. Two adjacent cortical veins were occluded photochemically using rose bengal dye and fiberoptic illumination, with evaluation 24 hours thereafter by magnetic resonance imaging (MRI). Each brain was removed from the skull immediately after MRI and processed for hematoxylin-eosin staining (H&E staining) of sections for histopathology and comparison with MRI data. VEGF expression as demonstrated immunohistochemically appeared to coincide with vasogenic edema, diagnosed as high intensity areas on apparent diffusion coefficient of water (ADCw) maps. On the basis of these data, we conclude that VEGF is related to formation of vasogenic edema in the acute stage of CVCD.

Selective and sustained occupancy of prostatic alpha1-adrenoceptors by oral administration of KMD-3213 and its plasma concentration in rats

This study examined the ex-vivo occupancy by KMD-3213 of alpha1-adrenoceptors in the prostate and other tissues of rats in terms of tissue selectivity and duration of occupancy in relation to plasma concentration. Oral administration of KMD-3213 (0.2-20.2 micromol kg(-1), 0.5 h) dose-dependently decreased [3H]prazosin binding sites (Bmax) in the prostate (42-74%) and submaxillary gland (54-88%) compared with the control value. In contrast, there was only a slight change in the Bmax values in the spleen and cerebral cortex of KMD-3213-treated rats. The alpha1-adrenoceptor occupancy in the prostate and submaxillary gland was increased, with plasma free concentration of KMD-3213 at 0.5 h after oral administration of KMD-3213 (0.6-20.2 micromol kg(-1)). The receptor occupancy in these tissues was much greater than that in the spleen, heart or cerebral cortex. After oral administration of KMD-3213 (6.1 micromol kg(-1)), the alpha1-adrenoceptor occupancy in the prostate and submaxillary gland occurred rapidly, in parallel with the rise in the plasma concentration of the drug, and it lasted for at least 24 h, despite a remarkable decrease in the plasma concentration. It is concluded that KMD-3213 may produce fairly selective and sustained occupancy of alpha1-adrenoceptors in the prostate, a target organ for treatment of bladder outlet obstruction in patients with benign prostatic hyperplasia.

The contribution of 2,3,5-trichlorophenyl methyl sulfone, a metabolite of 1,2,4-trichlorobenzene, to the delta-aminolevulinic acid synthetase induction by 1,2,4-trichlorobenzene in rat liver

In the present study, we investigated the contribution of methylsulfonyl metabolite derived from 1,2,4-trichlorobenzene (1,2,4-TCB) on the delta-aminolevulinic acid (ALA) synthetase induction by the parent compound in rats. The time courses of increasing of hepatic microsomal total cytochrome P450 content after a single i.p. administration of 1,2,4-TCB (1.36 mmol/kg), and 2,3,5- and 2,4,5-trichlorophenyl methyl sulfones (2,3,5- and 2,4,5-TCPSO2Mes) (50 micromol/kg each) were in parallel with those of increasing of the total heme content in liver microsomes. 1,2,4-TCB significantly increased the heme oxygenase activity, but 2,3,5- and 2,4,5-TCPSO2Mes did not. On the other hand, 1,2,4-TCB and 2,3,5-TCPSO2Me markedly enhanced the ALA synthetase activity. No change was observed in this enzyme activity after the administration of 2,4,5-TCPSO2Me. After the administration of 1,2,4-TCB to the rats treated with DL-buthionine-(S,R)-sulfoximine (BSO) and to the non-BSO-treated rats, the concentrations of both 2,3,5- and 2,4,5-TCPSO2Mes were significantly lower in liver of the BSO-treated rats than in liver of the non-BSO-treated rats. Additionally, the 1,2,4-TCB did not elevate the ALA synthetase activity in the BSO-treated rats. On the other hand, the administration of 2,3,5-TCPSO2Me to BSO-treated rats resulted in induction of ALA synthetase. The results strongly suggest that the methyl sulfone derived from 1,2,4-TCB, i.e., 2,3,5-TCPSO2Me, contributes highly to the induction of the ALA synthetase activity by the parent compound.

Metabolite of 2,2',4',5-tetrabromobiphenyl, 3-methylsulphonyl-2,2',4',5-tetrabromobiphenyl, a potent inducer of CYP2B1/2 in rat

1. 3-Methylsulphonyl- and 4-methylsulphonyl-2,2',4',5-tetrabromobiphenyls (3-MeSO(2)- and 4-MeSO(2)-TetraBrBs) were detected in the liver, lung, kidney, adipose tissue and faeces of the 2,2',4',5-tetrabromobiphenyl (TetraBrB)-dosed rat. 2. The administration of 0.05-2.0 micromol kg(-1) doses of 3-MeSO(2)-TetraBrB produced corrresponding increases in the hepatic concentration of the methyl sulphone metabolite, corresponding increases in the content of total cytochrome P450, and corresponding increases in the activities of 7-benzyloxy-, 7-ethoxy- and 7-pentoxyresorufin O-dealkylases. The inducing effects of the 3-MeSO(2)-TetraBrB (0.2 micromol kg(-1)), both on the content of total P450 and on the activities of the three alkoxyresorufin O-dealkylases, were higher than that of the parent TetraBrB (342 micromol kg(-1)). 3. The major phenobarbital (PB)-inducible forms of P450, CYP2B1, CYP2B2, CYP3A2 and CYP2C6, were substantially induced by 3-MeSO(2)-TetraBrB, but CYP1A1 and CYP1A2 were not. On the other hand, the activities of drug-metabolizing enzymes and the four PB-inducible forms of P450 were unchanged by 4-MeSO(2)-TetraBrB treatment. 4. The induction profiles of these enzymes and P450 forms in rat treated with 3-MeSO(2)-TetraBrB were similar to those treated with PB. 5. The inducing ability of 3-MeSO(2)-TetraBrB (0.5 micromol kg(-1)) both on the activities of the three alkoxyresorufin O-dealkylases and on the contents of four PB-inducible forms of P450 was roughly equal to that of PB (431 micromol kg(-1) twice at a 24-h interval) or 3-MeSO(2)-2,2',4',5-tetrachlorobiphenyl (1 micromol kg(-1)). It is noteworthy that the effects of 3-MeSO(2)-TetraBrB on the drug-metabolizing enzymes CYP2B1 and CYP2B2 were several thousand-fold higher than those of parent TetraBrB, while the effect of its isomeric 4-MeSO(2)-TetraBrB were not. 6. The extent of hepatic accumulation of the 3-MeSO(2) metabolite after the administration of TetraBrB (342 micromol kg(-1)) was almost the same as that after the administration of 3-MeSO(2)-TetraBrB (0.1-0.2 micromol kg(-1)). The relationship between the hepatic concentration of the 3-MeSO(2) metabolite and the extent of enzyme induction after the administration of TetraBrB or 3-MeSO(2)-TetraBrB suggests that 3-MeSO(2)-TetraBrB plays an important role in the induction of microsomal drug-metabolizing enzymes by TetraBrB.

High prevalence of anticardiolipin antibodies in patients with HCV-associated oral lichen planus

Hepatitis C virus (HCV) has been linked to extrahepatic manifestations such as oral lichen planus (OLP). In addition, anticardiolipin antibodies (aCL) and cryoglobulin have been demonstrated in chronic hepatitis C. The aim of this study was to investigate these prevalences in patients with HCV-associated OLP. The prospective study investigated the role of these factors in 133 subjects: 28 with OLP-HCV(+) (group 1), 22 with OLP-HCV(-) (group 2), 33 without OLP-HCV(+) (group 3), and 50 healthy volunteers matched for age and sex served as control group (group 4). Levels of immunoglobulin G (IgG) and IgM aCL antibodies, and cryoglobulin in serum were evaluated by enzyme-linked immunosorbent assay. The prevalence of aCL in groups 1, 2, 3, and 4 were 32.1, 18, 36.3, and 8%, respectively. The positive rate of aCL was significantly higher in groups 1 and 3 than that in the control group (group 1; p=0.02 vs. the control group, group 3; p<0.01 vs. the control group). There were no significant differences in cryoglobulin among the groups. The findings of the present study showed a high prevalence of IgG and IgM aCL in the serum of patients with HCV infectious diseases. A positive factor for aCL was determined by age, sex, the presence of OLP, and HCV infection.

Brain receptor binding characteristics and pharmacokinetic-pharmacodynamic analysis of thyrotropin-releasing hormone analogues

Thyrotropin-releasing hormone (TRH) receptor binding in the rat brain after intravenous (i.v.) injections of novel TRH analogues, taltirelin and montirelin, was examined and the data were analyzed in relation to their plasma concentrations which were simultaneously determined. Taltirelin and montirelin inhibited specific [3H]-Me-TRH binding in the rat brain and their Ki values were 311 and 35.2 nM, respectively. The i.v. injection of taltirelin and montirelin (0.1-3 mg/kg) produced a significant reduction in [3H]-Me-TRH binding sites (Bmax values) in the rat brain. The reduction by both agents tended to reach a maximum after 60 min and lasted up to at least 120 min. On the other hand, the i.v. injection of both agents had little significant effect on the apparent dissociation constant (Kd) for [3H]-Me-TRH in the rat brain. Plasma concentrations of taltirelin and montirelin in rats peaked immediately after i.v. injection, and thereafter they decreased with t 1/2 of 23.0 and 14.1 min, respectively. Counter-clockwise hysteresis between the plasma concentration and receptor occupancy of these agents was observed after the i.v. injection of taltirelin and montirelin, and the temporal delay between plasma concentration and brain receptor occupancy was successfully minimized using the "effect compartment" model in combination with the "linear-effect" model. We concluded that taltirelin and montirelin exert a fairly potent effect following sustained occupation of brain TRH receptors under in vivo condition. Thus, both agents could be clinically useful for the treatment of CNS disorders.

The human SDF1 gene polymorphism is located on a mutational hot spot that was identified by the hominoid genome study

Nucleotide sequences of a part of the stromal cell-derived factor-1 (SDF-1) gene 3' untranslated region were studied among hominoids (chimpanzees, gorillas, orangutans and gibbons). An identical sequence to the human SDF1-3'G allele was found in chimpanzees and gibbons, whereas that to the 3'A allele was found in gorillas. Based on the sequence data and the hominoid phylogenetic relation, it was suggested that an adenine nucleotide at nucleotide position (np) 801 in humans and gorillas was independently introduced into each lineage after the specific divergence and an ancestral hominoid sequence of this site (np 799-802) was deduced as CCGG. The present data showing a mutational hot spot on this site suggest the possible presence of multiple origins of the worldwide distribution of the SDF1-3'A allele in humans.

Characterization of specific [3H]nociceptin binding in rat brain and spinal cord

The present study was undertaken to characterize simultaneously [3H]nociceptin binding to opioid receptor-like 1 (ORL1) receptors in the rat brain and spinal cord. Specific binding of [3H]nociceptin to crude membranes from the rat brain and spinal cord at 25 degrees C was saturable, reversible and of high affinity, and it also exhibited a pharmacological specificity involving the ORL1 receptor. The Kd and Bmax values for [3H]nociceptin in the spinal cord were significantly lower than those in the brain. At 4 degrees C, there was a significant increase in the dissociation constant (Kd) for [3H]nociceptin in the brain and spinal cord with little change in the maximal number of binding sites (Bmax) compared with that at 25 degrees C. Nociceptin and its analogue, [Phe1 psi(CH2-NH)-Gly2]nociceptin(1-13)NH2 were found to be potent inhibitors of [3H]nociceptin binding to crude membranes from the brain and spinal cord, while opioid ligands such as naloxone-benzoylhydrazone, naltrindole and nor-binaltorphimine, exhibited an inhibitory effect only at high concentrations. The Ki values for nociceptin, its analogue and opioid ligands in the spinal cord were significantly lower than those in the brain. There were regional variations in the specific [3H]nociceptin binding to crude membranes from the rat brain: a relatively high density of [3H]nociceptin binding in the cerebral cortex, hippocampus, thalamus and midbrain, moderately dense binding in the corpus striatum and pons/medulla oblongata, and the lowest density of binding in the cerebellum. In conclusion, the present study has shown that [3H]nociceptin binds selectively to ORL1 receptors in the rat brain and spinal cord.

Improved brain delivery of a nonsteroidal anti-inflammatory drug with a synthetic glyceride ester: a preliminary attempt at a CNS drug delivery system for the therapy of Alzheimer's disease

1,3-Diacetyl-2-ketoprofen glyceride (DAKG), a prodrug of ketoprofen, was synthesized as a model compound in our attempt to develop a central nervous system (CNS) drug delivery system to treat Alzheimer's disease. The primary purpose of the present study is to test whether DAKG improves the delivery of ketoprofen to the brain and to quantitatively evaluate several factors that influence the brain distribution of this prodrug. ddY mice were injected with either ketoprofen or DAKG at a dose of 40 micromol/kg and then the plasma and brain pharmacokinetics of these agents were assessed. The brain uptake clearance of ketoprofen and DAKG across the BBB was measured by in situ mouse brain perfusion. In addition, the efflux permeability of ketoprofen through the BBB was evaluated using the in vivo mouse brain microdialysis technique. The in vivo metabolism of DAKG in the brain was assessed by a short infusion into the internal carotid artery coupled with the brain metabolism index (BMI) method. Administration of DAKG produced an approximately 3-fold increase in the area under the brain concentration - time curve of ketoprofen, compared with administration of ketoprofen itself. The brain uptake clearance (CL(in) ) of ketoprofen across the BBB was 0.0308 +/- 0.0046 mL/min/g whereas the CL(in) of DAKG was 1.60 +/- 0.16 mL/min/g, suggesting a marked increase in BBB permeability following lipidization of ketoprofen. The BMI method confirmed that DAKG is taken up by the brain to rapidly release ketoprofen in a dose-dependent manner. The in vitro metabolism studies revealed that isolated bovine brain capillaries as well as whole brain homogenate have the hydrolysis activity to DAKG. In addition, the brain concentration of ketoprofen after DAKG administration was maintained for a significant period following co-administration of probenecid. These results suggest that DAKG improves the delivery of ketoprofen to the brain, and this improved delivery is due to avid uptake of DAKG across the BBB followed by rapid hydrolysis to ketoprofen within the brain. The ketoprofen produced in the brain was probably cleared by the active efflux system operating in the BBB. Significant inhibition of this efflux system by co-administration of probenecid could result in a sustained concentration of ketoprofen in the brain following DAKG administration.

Alterations in tight junctions differ between primary biliary cirrhosis and primary sclerosing cholangitis

Tight junctions (TJ) of biliary epithelial cells (BEC) and hepatocytes prevent bile regurgitation from the biliary tract. Alterations in these TJs may participate in chronic cholestatic liver diseases such as primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). We examined the localization of 2 TJ proteins, ZO-1 and 7H6, in these diseases. Frozen sections from livers of PBC, PSC, extrahepatic cholestasis (Ex-C), and hepatitis C-associated cirrhosis (LC-C), as well as histologically normal livers, were processed for double-fluorescence immunohistochemistry. In controls and cirrhosis, 7H6 and ZO-1 colocalized surrounding the luminal space of the bile ducts and outlined the bile canalicular spaces between hepatocytes. In untreated PBC, immunostaining for ZO-1 in BEC of bile ducts 40 to 80 microm in diameter was preserved, but that for 7H6 was diminished to absent. In PBC treated with ursodeoxycholic acid (UDCA), immunostaining for 7H6 was well preserved. In PSC as well as in Ex-C, immunostaining for both 7H6 and ZO-1 was well preserved in bile ducts. In hepatocytes, ZO-1 showed preserved immunoreactivity, but immunostaining for 7H6 frequently disappeared. The percentage of bile ducts with immunostaining for 7H6 in all bile ducts with immunostaining for ZO-1 was significantly reduced in PBC compared with that in control, LC-C, Ex-C, and PSC (all P <.0001). Substantial alteration in the TJ protein occurs predominantly in bile ducts in PBC and in hepatocytes in PSC, suggesting increased paracellular permeability along different paracellular routes for bile regurgitation in these chronic cholestatic liver diseases.

Muscarinic receptor binding characteristics in rat tissues after oral administration of oxybutynin and propiverine

Ex vivo muscarinic receptor binding of oxybutynin and propiverine, the most commonly used anticholinergic agents for the treatment in patients with urinary incontinence, was investigated in rat tissues. The oral administration of oxybutynin (50.8 and 127 micromol/kg) caused a significant increase in the apparent dissociation constant (Kd) for specific (-)-[3H]QNB binding in the rat bladder, prostate, submaxillary gland, heart and cerebral cortex, compared with each of the control values. Also, in the submaxillary gland of these rats, there was a reduction in the maximal number of binding sites (Bmax) for (-)-[3H]QNB binding. Similarly, oral administration of propiverine at doses of 74.3-297 micromol/kg brought about a significant increase in the Kd values for (-)-[3H]QNB binding in rat tissues including the bladder, and greater increase in Kd values was seen in the rat prostate, heart and submaxillary gland. On the other hand, oral administration of propiverine, unlike oxybutynin, resulted in very little reduction in the Bmax valules for (-)-[3H]QNB binding in the submaxillary gland. In conclusion, the present study has shown that oxybutynin and propiverine, after oral administration, bind significantly to muscarinic receptors in tissues such as the bladder, which is the target organ for the treatment of urinary incontinence, and that oxybutynin appears to exhibit long-term binding to muscarinic receptors in the salivary gland.

[Species differences in the in vitro metabolism of 2,4,5,2',3',4'-hexachlorobiphenyl]

In vitro Metabolism of 2,4,5,2',3',4'-hexachlorobiphenyl (CB138) was studied using liver microsomes from rats, hamsters and guinea pigs. Guinea pig liver microsomes formed four metabolites named as M-1, M-2, M-3 and M-4 and these metabolites were all increased to about 4-5 fold of untreated microsomes by pretreatment of phenobarbital. Liver microsomes of rats and hamsters showed much less activity to metabolize CB138 than those of guinea pigs. Only phenobarbital-treated microsomes produced very small amounts of M-3 in rats and M-1, M-2 and M-3 in hamsters, but untreated and MC-treated microsomes did not. When mass spectra of the methylated derivatives of M-1, M-2, M-3 and M-4 were measured in GC/MS, the former two possess the molecular ion of 354 and the latter two had the molecular ion of 388. In addition, the mass fragmentation pattern indicated that M-1, M-2, M-3 and M-4 are 2-OH-4,5,2',3',4'-pentachlorobiphenyl, 5-OH-2,4,2',3',4'-pentachlorobiphenyl, 3-OH-CB138 and 2-OH-3,4,5,2',3',4'-hexachlorobiphenyl, respectively. Of four metabolites, the chemical structures of M-3 and M-4 were supported by the synthesized authentic compounds. From these results, it is suggested that the metabolism of CB138 in guinea pig liver proceeds mainly via 2,3-epoxide as an intermediate and a PB-inducible P450, CYP2B18, is the most important isozyme in CB138 metabolism.

Involvement of p21(WAF1/Cip1), p27(Kip1), and p18(INK4c) in troglitazone-induced cell-cycle arrest in human hepatoma cell lines

Peroxisome proliferator-activated receptor gamma (PPARgamma) regulates cell growth and differentiation. Recent evidence has suggested that PPARgamma ligands had anti-tumor effects through inhibiting cell growth and inducing cell differentiation in several types of malignant neoplasm. In the present study, we investigated: 1) the expression of PPARgamma in both human hepatoma cell lines and 5 resected human hepatocellular carcinoma (HCC) tissues; 2) the growth-inhibitory effect of troglitazone, a PPARgamma ligand, on those hepatoma cells; and 3) the molecular mechanisms of troglitazone-induced cell-cycle arrest. Five hepatoma cell lines, HLF, HuH-7, HAK-1A, HAK-1B, and HAK-5, were used. The mRNA expression levels of PPARgamma, p21(WAF1/Cip1), and p27(Kip1) were determined by real-time quantitative reverse transcription-polymerase chain reaction. The expression of cell cycle-regulating proteins, such as p21, p27, p18(INK4c), cyclin E, and pRb, was examined using Western blotting. PPARgamma was constitutively expressed in all the cell lines and the HCC tissues used in this study. A cytostatic effect of troglitazone was found in those cell lines, and this inhibition of cell growth was dosage-dependent. G0/G1 arrest was apparently demonstrated in flow cytometric analysis in HLF, HAK-1A, HAK-1B, and HAK-5, all of which showed an increased expression of p21 protein. However, HuH-7, lacking p21 protein expression, did not demonstrate clear arrest in the cell-cycle analysis. HLF, which was deficient in the protein product of the retinoblastoma tumor-suppressor gene (pRb), responded most profoundly to troglitazone, showing an increased expression in not only p21, but also in p27 and in p18. These findings suggested that p21, p27, and p18 might be involved in troglitazone-induced cell-cycle arrest in human hepatoma cells.