Hypomyelinating Leukodystrophy 10 (HLD10)-Associated Mutations of PYCR2 Form Large Size Mitochondria, Inhibiting Oligodendroglial Cell Morphological Differentiation.

Hypomyelinating leukodystrophy 10 (HLD10) is an autosomal recessive disease related to myelin sheaths in the central nervous system (CNS). In the CNS, myelin sheaths are derived from differentiated plasma membranes of oligodendrocytes (oligodendroglial cells) and surround neuronal axons to achieve neuronal functions. Nucleotide mutations of the pyrroline-5-carboxylate reductase 2 (PYCR2) gene are associated with HLD10, likely due to PYCR2's loss-of-function. PYCR2 is a mitochondrial residential protein and catalyzes pyrroline-5-carboxylate to an amino acid proline. Here, we describe how each of the HLD10-associated missense mutations, Arg119-to-Cys [R119C] and Arg251-to-Cys [R251C], lead to forming large size mitochondria in the FBD-102b cell line, which is used as an oligodendroglial cell differentiation model. In contrast, the wild type proteins did not participate in the formation of large size mitochondria. Expression of each of the mutated R119C and R251C proteins in cells increased the fusion abilities in mitochondria and decreased their fission abilities relatively. The respective mutant proteins, but not wild type proteins also decreased the activities of mitochondria. While cells expressing the wild type proteins exhibited differentiated phenotypes with widespread membranes and increased expression levels of differentiation marker proteins following the induction of differentiation, cells harboring each of the mutant proteins did not. Taken together, these results indicate that an HLD10-associated PYCR2 mutation leads to the formation of large mitochondria with decreased activities, inhibiting oligodendroglial cell morphological differentiation. These results may reveal some of the pathological mechanisms in oligodendroglial cells underlying HLD10 at the molecular and cellular levels.

Hesperetin, a Citrus Flavonoid, Ameliorates Inflammatory Cytokine-Mediated Inhibition of Oligodendroglial Cell Morphological Differentiation.

Oligodendrocytes (oligodendroglial cells) are glial cells that wrap neuronal axons with their differentiated plasma membranes called myelin membranes. In the pathogenesis of inflammatory cytokine-related oligodendroglial cell and myelin diseases such as multiple sclerosis (MS), typical inflammatory cytokines tumor necrosis factor α (TNFα) and interleukin-6 (IL-6) are thought to contribute to the degeneration and/or progression of the degeneration of oligodendroglial cells and, in turn, the degeneration of naked neuronal cells in the central nervous system (CNS) tissues. Despite the known involvement of these inflammatory cytokines in disease progression, it has remained unclear whether and how TNFα or IL-6 affects the oligodendroglial cells themselves or indirectly. Here we show that TNFα or IL-6 directly inhibits morphological differentiation in FBD-102b cells, which are differentiation models of oligodendroglial cells. Their phenotype changes were supported by the decreased expression levels of oligodendroglial cell differentiation and myelin marker proteins. In addition, TNFα or IL-6 decreased phosphorylation levels of Akt kinase, whose upregulation has been associated with promoting oligodendroglial cell differentiation. Hesperetin, a flavonoid mainly contained in citrus fruit, is known to have neuroprotective effects. Hesperetin might also be able to resolve pre-illness conditions, including the irregulated secretion of cytokines, through diet. Notably, the addition of hesperetin into cells recovered TNFα- or IL-6-induced inhibition of differentiation, as supported by increased levels of marker protein expression and phosphorylation of Akt kinase. These results suggest that TNFα or IL-6 itself contributes to the inhibitory effects on the morphological differentiation of oligodendroglial cells, possibly providing information not only on their underlying pathological effects but also on flavonoids with potential therapeutic effects at the molecular and cellular levels.

Imaging evaluation of the cartilage in rheumatoid arthritis patients with an x-ray phase imaging apparatus based on Talbot-Lau interferometry.

X-ray Talbot-Lau interferometry is one of the x-ray phase imaging methods that has high sensitivity in depicting soft tissues. Unlike earlier x-ray phase imaging methods that required particular types of x-ray sources, such as a synchrotron or a micro-focus x-ray tube, x-ray Talbot-Lau interferometry enables to perform clinical x-ray phase imaging using a conventional x-ray source with a relatively compact configuration. We developed an apparatus to depict cartilage in the metacarpophalangeal joints of the hands. In addition, we examined the apparatus performance by applying it to healthy volunteers and patients with rheumatoid arthritis (RA). Cartilage deformation, which is thought to be a precursor of destruction of the joints, was successfully depicted by the apparatus, suggesting a potential early diagnosis of RA.

Entrainment of the Circadian Clock in Neural Stem Cells by Epidermal Growth Factor is Closely Associated with ERK1/2-mediated Induction of Multiple Clock-related Genes.

The mitotic activity of certain tissues in the body is closely associated with circadian clock function. However, the effects of growth factors on the molecular clockwork are not fully understood. Stimulation of neural stem cells (NSCs) with epidermal growth factor (EGF), a well-known mitogen, is known to cause synchronized cell cycle progression with a period of approximately 24 h, closely associated with the Per2 gene expression rhythm. Here, we examined the effects of EGF on the molecular clockwork of NSCs. Treatment of cultured NSCs derived from embryonic mouse forebrain with EGF (20 ng/mL) caused a phase shift in the PER2::LUCIFERASE bioluminescence rhythm in a stimulation time-dependent manner. The EGF phase-response curve differed from that of forskolin (FK)-a well-known chemical resetting stimulus-both in the advance/delay ratio and stimulation time-dependency. PCR array analysis followed by quantitative PCR validation demonstrated that EGF treatment transiently induced multiple clock-related genes including Per1, Per2, Dec1, e4bp4, and Noct, whereas FK treatment induced a limited number of genes (Per1 and Dec1), suggesting that the mode of entrainment of NSC molecular clock was different for EGF and FK. EGF led to gene induction in the presence of cycloheximide, suggesting that de novo protein synthesis is unnecessary. Pretreatment with the MEK1/2 inhibitor U0126 significantly suppressed the acute induction of Per2, Dec1, and Noct by EGF and also abolished the EGF-induced phase shift of the PER2::LUCIFERASE rhythm in NSCs. These results suggest a unique effect of EGF on the molecular clockwork of NSCs.

Need for medication to complement catecholamines in smoking cessation of hardcore smokers.

Many smokers find it difficult to stop smoking without assistance. The antidepressants bupropion and nortriptyline can aid smoking cessation. The main aim of this study was to understand the pathophysiology of smoking cessation better based on biological backgrounds. We investigated the following biological markers for any alterations during smoking cessation in the absence of pharmacotherapy: the dopamine metabolite homovanillic acid (HVA), the noradrenaline metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) and brain-derived neurotrophic factor (BDNF). Assessment and blood sampling were performed at a baseline (the start) time point and at a critical time point during smoking cessation. Seven of 30 smokers quit during a 16-week follow-up period; these smokers were defined as remission group from tobacco dependence. The remaining 23 smokers were categorized as hardcore smokers. The smoking group was compared with 23 non-smokers matched for age and gender. We compared blood levels of biological markers in each of the three groups. The hardcore smoker group showed significant decreases in HVA and MHPG levels between baseline and the critical time point (p=0.018 and p=0.033, respectively). However, the remission from tobacco dependence group exhibited no significant changes in any of the biomarkers examined. They had lower scores on the Minnesota nicotine withdrawal scale than the hardcore smoker group (p=0.002). The hardcore smoker group had higher MHPG and BDNF levels than the non-smoker group (p=0.002 and p<0.001, respectively). Hardcore smokers experience severe nicotine withdrawal symptoms. Nicotine withdrawal is associated with catecholamine deficiency. The resulting withdrawal symptoms make quitting difficult for hardcore smokers. These hardcore smokers may require medication to compensate for the catecholamine deficit. Non-nicotinic medications such as bupropion, nortriptyline, or varenicline may be required to bolster the catecholamine deficit in hardcore smokers.

Non-24-hour sleep-wake syndrome improved by low-dose valproic acid: a case report.

A woman was diagnosed with non-24-hour sleep-wake syndrome and depressive symptoms. Her depressive symptoms did not respond to standard doses of several antidepressants or mood stabilizers. Furthermore, her sleep-wake cycle remained non-entrained despite treatment with a melatonin-related drug, vitamin B12, and phototherapy. Ultimately, her sleep-wake rhythm was restored to a 24-hour pattern with a low dose of valproic acid, and her depressive symptoms tended to improve as a result of synchronization without antidepressants. Low-dose valproic acid appears to be one of the effective means of entraining circadian rhythms in patients with non-24-hour sleep-wake syndrome, which in turn likely improves associated depressive symptoms.

Yokukansan improves behavioral and psychological symptoms of dementia by suppressing dopaminergic function.

Although three drugs, risperidone, yokukansan, and fluvoxamine, have shown equal efficacy in treating behavioral and psychological symptoms of dementia (BPSD) in our previous study, their mechanisms of action are different from one another. Monoamines have attracted attention for their key roles in mediating several behavioral symptoms or psychological symptoms through synaptic signaling. We aimed to clarify the monoamines changed by treatment with each drug in patients with BPSD. The main purpose of this study was to determine whether plasma levels of catecholamine metabolites are correlated with pharmacological treatments. This was an 8-week, rater-blinded, randomized, flexible-dose, triple-group trial. In total, 90 subjects were recruited and subsequently three different drugs were allocated to 82 inpatients with BPSD. We examined BPSD data from patients who completed 8 weeks of treatment. Eventually, we analyzed 42 patients (yokukansan: 17; risperidone: 9; fluvoxamine: 16). Homovanillic acid, a metabolite of dopamine, and 3-methoxy-4-hydroxyphenylglycol, a metabolite of noradrenaline, in their plasma were analyzed by high-performance liquid chromatography with electrochemical detection. All three drugs showed equal significant efficacy between baseline and study endpoint. By contrast, biomarkers showed mutually different changes. Patients in the yokukansan group had significantly decreased plasma homovanillic acid levels from baseline. Conversely, patients in the risperidone and fluvoxamine groups exhibited no significant changes in plasma homovanillic acid levels from baseline. Yokukansan contains geissoschizine methyl ether, which is known to have a partial agonist effect on dopamine D2 receptors. An improvement in BPSD condition with the intake of yokukansan is suggested to occur through a suppressed dopaminergic function, which is similar to the effect of aripiprazole.

Endogenous interleukin 18 regulates testicular germ cell apoptosis during endotoxemia.

Orchitis (testicular swelling) often occurs during systemic inflammatory conditions, such as sepsis. Interleukin 18 (IL18) is a proinflammatory cytokine and is an apoptotic mediator during endotoxemia, but the role of IL18 in response to inflammation in the testes was unclear. WT and IL18 knockout (KO) mice were injected lipopolysaccharide (LPS) to induce endotoxemia and examined 12 and 48  h after LPS administration to model the acute and recovery phases of endotoxemia. Caspase activation was assessed using immunohistochemistry. Protein and mRNA expression were examined by western blot and quantitative real-time RT-PCR respectively. During the acute phase of endotoxemia, apoptosis (as indicated by caspase-3 cleavage) was increased in WT mice but not in IL18 KO mice. The death receptor-mediated and mitochondrial-mediated apoptotic pathways were both activated in the WT mice but not in the KO mice. During the recovery phase of endotoxemia, apoptosis was observed in the IL18 KO mice but not in the WT mice. Activation of the death-receptor mediated apoptotic pathway could be seen in the IL18 KO mice but not the WT mice. These results suggested that endogenous IL18 induces germ cell apoptosis via death receptor mediated- and mitochondrial-mediated pathways during the acute phase of endotoxemia and suppresses germ cell apoptosis via death-receptor mediated pathways during recovery from endotoxemia. Taken together, IL18 could be a new therapeutic target to prevent orchitis during endotoxemia.

The noradrenaline metabolite MHPG is a candidate biomarker between the depressive, remission, and manic states in bipolar disorder I: two long-term naturalistic case reports.

BACKGROUND: Treatment of the depressive and manic states in bipolar disorder I (BDI) is a challenge for psychiatrists. Despite the recognized importance of the switch phenomenon, the precise mechanisms underlying this process are yet to be shown. We conducted a naturalistic study in two BDI patients to determine whether biological markers (monoamine metabolites and brain-derived neurotrophic factor [BDNF]) are associated with the switch between depressive and manic states. CASE PRESENTATION AND METHODS: Blood sampling and mood assessments were performed at 2-week intervals over a period of 2 (Case 1, n=72) and 6 (Case 2, n=183) years. Plasma concentrations of 3-methoxy-4-hydroxyphenylglycol (MHPG) and homovanillic acid (HVA) were analyzed by high-performance liquid chromatography with electrochemical detection. Plasma BDNF was assayed by sandwich ELISA (enzyme-linked immunosorbent assay). RESULTS: MHPG had the highest standardized coefficient (ß) in the multiple regression analysis. We found a significant positive correlation between Young Mania Rating Scale scores and plasma MHPG levels (Case 1: ρ=0.429; Case 2: ρ=0.488), and a significant negative correlation between Montgomery-Asberg Depression Rating Scale scores and MHPG levels (Case 1: ρ=-0.542; Case 2: ρ=-0.465). Conversely, no significant correlation was found between the level of BDNF and the presence of a manic or depressive state, and although HVA had a slightly stronger correlation than MHPG, the levels of neither of these were found to significantly correlate with the symptoms. CONCLUSION: These data suggest that peripheral MHPG levels (which is related to noradrenaline levels in the brain) could be used as a biomarker of mood states in BDI. The noradrenaline level in the brain is likely to reflect the clinical characteristics of the switch process in BDI, and has prognostic significance for the treatment of both manic and depressive states.

The noradrenaline metabolite MHPG is a candidate biomarker from the manic to the remission state in bipolar disorder I: a clinical naturalistic study.

Remission is the primary goal of treatment for bipolar disorder I (BDI). Metabolites of noradrenaline and dopamine, 3-methoxy-4-hydroxyphenylglycol (MHPG) and homovanillic acid (HVA), respectively, are reduced by treatment with antipsychotics, but whether these phenomena are caused by antipsychotics or by the pathophysiology of BDI is not known. Interactions between brain-derived neurotrophic factor (BDNF) and mood disorders have also been suggested. We conducted a multifaceted study in BDI patients to ascertain if biological markers are associated with the manic state. Patients with Young Mania Rating Scale (YMRS) scores >20 participated in the study. Final analyses involved 24 BDI patients (13 men and 11 women). We used YMRS scores to identify mania stages in individual BDI patients (i.e., manic syndrome, response and remission stages). Statistical analyses were done using one-way repeated-measures analyses of variance (rep-ANOVA) throughout manic syndrome, response and remission stages. Plasma concentrations of MHPG and HVA were analyzed by high-performance liquid chromatography with electrochemical detection. Plasma levels of BDNF were measured by sandwich enzyme-linked immunosorbent assay. BDI patients had significantly reduced plasma levels of MHPG throughout manic syndrome, response and remission stages (rep-ANOVA, p = 0.002). Without a case of response state, there was a significant positive correlation between YMRS scores and plasma levels of MHPG (ρ = 0.33, p = 0.033, n = 48). Plasma levels of HVA and BDNF were not significantly altered throughout manic syndrome, response and remission stages. These data suggest that the peripheral level of MHPG (which is associated with noradrenaline levels in the brain) could be used as a biomarker for the manic state in BDI. The MHPG level is likely to reflect the clinical characteristics of the manic syndrome in BDI, and noradrenaline may reflect the pathophysiology from manic to remission states.

Efficacy and tolerability of risperidone, yokukansan, and fluvoxamine for the treatment of behavioral and psychological symptoms of dementia: a blinded, randomized trial.

The descriptive term behavioral and psychological symptoms of dementia (BPSD) is used to cover a range of noncognitive disturbances including anxiety, depression, irritability, aggression, agitation, eating disorders, and inappropriate social or sexual behaviors. Behavioral and psychological symptoms of dementia are seen in about 90% of patients with dementia. We aimed to compare the efficacy and tolerability of risperidone, yokukansan, and fluvoxamine used for BPSD in elderly patients with dementia. Ninety inpatients with dementia according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria were investigated in Sato Hospital, Koutokukai. We conducted an 8-week, rater-blinded, randomized trial, administering flexibly dosed risperidone, yokukansan, or fluvoxamine. Primary outcome measures were Neuropsychiatric Inventory in Nursing Home Version total score and its items. Secondary outcome measures were cognitive function measured by Mini-Mental State Examination and daily life function measured by Functional Independence Measure (FIM). Neurological adverse effects were measured by the Drug-Induced Extra-Pyramidal Symptoms Scale. At the end of the study, we analyzed 76 patients (92.7%). Mean Neuropsychiatric Inventory in Nursing Home Version total score decreased in all 3 drug groups, with no significant between-group differences. Mini-Mental State Examination and Functional Independence Measure scores did not change significantly. Drug-Induced Extra-Pyramidal Symptoms Scale scores did not change in the yokukansan and fluvoxamine groups, but increased significantly in the risperidone group. Risperidone, yokukansan, and fluvoxamine were equally effective in the treatment of BPSD in elderly patients. However, yokukansan or fluvoxamine for BPSD showed a more favorable profile in tolerability compared with risperidone. This trial is registered at UMIN Clinical Trials Registry (identifier: UMIN000006146).

Prognostic value of organic anion transporting polypeptide 1B3 and copper transporter 1 expression in endometrial cancer patients treated with paclitaxel and carboplatin.

Paclitaxel and carboplatin (TC) chemotherapy is an effective and well-tolerated regimen against advanced endometrial cancer. Organic anion transporting polypeptide 1B3 (OATP1B3) and copper transporter 1 (CTR1) are critical for the uptake of paclitaxel and carboplatin, respectively. This study aimed to address the prognostic impact of OATP1B3 and CTR1 in endometrial cancer patients treated with adjuvant TC chemotherapy. We immunohistochemically evaluated the expressions of OATP1B3 and CTR1 in 47 stage III endometrial cancers. The high expression levels of OATP1B3 were significantly correlated with type I tumor (P = 0.0005). In univariate analysis, high expression levels of OATP1B3 (P = 0.047) and CTR1 (P = 0.009) were significantly associated with longer disease-free survival (DFS) and longer overall survival (OS), respectively. The patients with tumors showing high expression levels of at least one of OATP1B3 and CTR1 had potentially longer DFS (P = 0.058) and significantly longer OS (P = 0.003) sin the univariate analysis. Combined OATP1B3/CTR1 expression was the sole independent prognostic factor for longer OS in the multivariate analysis (P = 0.013). Our findings suggest that combined OATP1B3/CTR1 expression is a possible predictive/prognostic factor for a good outcome in stage III endometrial cancer patients treated with adjuvant TC chemotherapy.

Cadaveric and in vivo human joint imaging based on differential phase contrast by X-ray Talbot-Lau interferometry.

We developed an X-ray phase imaging system based on Talbot-Lau interferometry and studied its feasibility for clinical diagnoses of joint diseases. The system consists of three X-ray gratings, a conventional X-ray tube, an object holder, an X-ray image sensor, and a computer for image processing. The joints of human cadavers and healthy volunteers were imaged, and the results indicated sufficient sensitivity to cartilage, suggesting medical significance.

Immunohistochemical analysis of organic anion transporter 2 and reduced folate carrier 1 in colorectal cancer: Significance as a predictor of response to oral uracil/ftorafur plus leucovorin chemotherapy.

Colorectal cancer is one of the most common malignancies in developed countries and chemotherapy is the standard treatment option for advanced colorectal cancer. Identification of biomarkers for predicting response to uracil/ftorafur plus leucovorin (UFT/LV) chemotherapy is an important issue in colorectal cancer treatment. Organic anion transporter 2 (OAT2) and reduced folate carrier 1 (RFC1) are the major uptake transporters of 5-fluorouracil (5-FU) and LV, respectively. In the present study, the correlation between OAT2 and RFC1 expression and histological response to preoperative UFT-based (UFT or UFT/LV) chemotherapy was investigated. Pre-treatment biopsy specimens obtained from 45 patients were evaluated for OAT2 and RFC1 expression levels by using an immunohistochemical approach. A high expression of OAT2 and RFC1 was significantly correlated with good response to UFT-based chemotherapy (P<0.0001 and P= 0.002, respectively). In multivariate logistic regression analysis, a high OAT2 expression was an independent predictor of good response to UFT-based chemotherapy (P=0.02), unlike RFC1 expression. High expression levels of OAT2 were significantly correlated with a good response in the UFT-treated (P= 0.04) as well as the UFT/LV-treated (P<0.0005) groups; however, RFC1 expression levels were significantly correlated with a good response only in the UFT/LV-treated group (P=0.02). Therefore, immunohistochemical analysis of OAT2 and RFC1 may serve as a useful tool for predicting the efficacy of UFT/LV treatment regimens in colorectal cancer patients.

Plasma brain-derived neurotrophic factor levels predict the clinical outcome of depression treatment in a naturalistic study.

UNLABELLED: Remission is the primary goal of treatment for major depressive disorder (MDD). However, some patients do not respond to treatment. The main purpose of this study was to determine whether brain-derived neurotrophic factor (BDNF) levels are correlated with treatment outcomes. In a naturalistic study, we assessed whether plasma BDNF levels were correlated with clinical outcomes by measuring plasma BDNF in patients with depressive syndrome (MADRS score ≥ 18), and subsequently comparing levels between the subgroup of patients who underwent remission (MADRS score ≤ 8) and the subgroup who were refractory to treatment (non-responders). Patients with depressive syndrome who underwent remission had significantly higher plasma BDNF levels (p<0.001), regardless of age or sex. We also found a significant negative correlation between MADRS scores and plasma BDNF levels within this group (ρ = -0.287, p = 0.003). In contrast, non-responders had significantly lower plasma BDNF levels (p = 0.029). Interestingly, plasma BDNF levels in the non-responder group were significantly higher than those in the remission group in the initial stage of depressive syndrome (p = 0.002). Our results show that plasma BDNF levels are associated with clinical outcomes during the treatment of depression. We suggest that plasma BDNF could potentially serve as a prognostic biomarker for depression, predicting clinical outcome. TRIAL REGISTRATION: UMIN Clinical Trials Registry UMIN000006264.

Divergent effects of lithium and sodium valproate on brain-derived neurotrophic factor (BDNF) production in human astrocytoma cells at therapeutic concentrations.

Mood stabilizers such as lithium (Li) or valproic acid (VPA) are used in the therapy of bipolar disorders, but the mechanisms by which these medicines work is unclear. Recently, neuroprotection has attracted attention as a potential action for VPA and Li. The close spatial relationship of the pre- and post-synapse with an astrocyte process within a 'tripartite synapse' suggests that mood stabilizer actions on astrocytes may be important. Therefore, we examined the effect of Li and VPA, at therapeutic concentrations, on brain-derived neurotrophic factor (BDNF) production in cultured human astrocytoma cells over an extended period of exposure. Released (extracellular) and intracellular BDNF was measured with sandwich-ELISA. Intracellular BDNF mRNA was also quantified using RT-PCR. VPA treatment potentiated the level of extracellular BDNF, whereas Li reduced it. Furthermore, VPA caused increased intracellular levels of BDNF protein and mRNA, while exposure to Li led to no significant differences compared to control cells. We suggest the possibility that VPA and Li have divergent effects on astrocyte BDNF production. Mood stabilizers play an essential role in regulating BDNF not only in neurons, but also in astrocytes. These findings could form the basis of a new astrocyte-targeted approach towards developing effective medications to treat bipolar disorders.

Intramolecular hydrogen atom tunneling in 2-chlorobenzoic acid studied by low-temperature matrix-isolation infrared spectroscopy.

Intramolecular hydrogen atom tunneling in 2-chlorobenzoic acid has been investigated by low-temperature matrix-isolation infrared spectroscopy with the aid of density functional theory calculation. Infrared spectra of two relatively stable syn isomers, SC and ST, were observed in argon and xenon matrixes. When the matrix samples were annealed after deposition, the isomerization from ST to SC occurred around the benzene-carboxyl bond. Two less stable anti isomers, AT, which has an OH...Cl intramolecular hydrogen bond, and AC, which has no OH...Cl bond, were produced from SC and ST upon UV irradiation. When the matrix samples were kept in the dark after UV irradiation, AT and AC changed to ST and SC, respectively, by spontaneous isomerization around the C-O axis in the carboxyl group. The rate constants of isomerization, AT --> ST, in a Xe matrix were estimated from the absorbance changes at various matrix temperatures. The rate constants showed a drastic decrease in deuteration of the hydrogen atom of the carboxyl group. The relationship between the rate constants and the matrix temperature did not follow the Arrhenius law. These findings lead to the conclusion that the isomerization of AT --> ST and AC --> SC in low-temperature rare-gas matrixes proceeds through intramolecular hydrogen atom tunneling.

Sodium valproate at therapeutic concentrations changes Ca2+ response accompanied with its weak inhibition of protein kinase C in human astrocytoma cells.

Sodium valproate (VPA) has been used clinically for treatment of not only epilepsy but also mood disorder. Although VPA is effective for treatment of epilepsy via inhibition of gamma-aminobutyric acid transaminase, it remains unknown why VPA is effective for the treatment of mood disorder. The authors examined the effect of VPA at therapeutic concentrations (300 and 600 microM) on the elevation of intracellular free calcium concentration ([Ca(2+)](i)) induced by carbachol, a muscarinic receptor agonist, in 1321N1 human astrocytoma cells. Treatment of the cells with 300 and 600 microM VPA for 2 min did not change the carbachol-induced [Ca(2+)](i) elevation. Treatment with 300 and 600 microM VPA for 48 h, however, reduced the elevation. Since we have shown that Li(+) reduced carbachol-induced [Ca(2+)](i) elevation in protein kinase C (PKC)-downregulated 1321N1 cells [Kurita, M., Mashiko, H., Rai, M., Kumasaka, T., Kouno, S., Niwa, S., Nakahata, N., 2002. Lithium chloride at a therapeutic concentration reduces Ca(2+)response in protein kinase C down-regulated human astrocytoma cells, Eur. J. Pharmacol. 442, 17-22.], the activity of PKC was examined. Treatment with VPA at the same concentrations for 24 or 48 h weakly reduced protein kinase C activity in membrane and cytosol fractions from the cells. On the other hand, the treatment of the cells with 600 microM VPA for 24 or 48 h slightly increased the B(max) value, but not the K(d) value, in the binding of [(3)H]quinuclidinyl benzylate, a muscarinic receptor ligand, to the membranes, suggesting that the number or affinity of muscarinic receptor did not decrease after VPA treatment. These results indicate that VPA at therapeutic concentrations slightly decreases the PKC activity and inhibits muscarinic receptor-mediated [Ca(2+)](i) elevation probably through change in the intracellular signaling pathway. VPA-induced reduction of PKC activity and [Ca(2+)](i) elevation may play a role in the treatment of mood disorder.

Structure of a new tetranuclear iron(III) complex with an oxo-bridge; factors to govern formation and stability of oxo-bridged iron(III) species in the L-subunit of ferritin.

We have investigated the reaction products of several iron(III) compounds with hydrogen peroxide, and have found that hydrogen peroxide promotes the formation of an oxo-bridged iron(III) species in the presence of methanol (electron donor), and carboxyl groups of the ligand systems play a role to give the tetranuclear iron(III) compound containing a bent Fe-O-Fe unit (O: oxo oxygen atom). Based on the present results and the facts that L-chains of human ferritins lack ferroxidase activity, but are richer in carboxyl groups (glutamates) exposed on the cavity surface, it seems reasonable to conclude that (i) the hydrogen peroxide released in the H-subunit may contribute to the formation of a diferric oxo-hydrate in the L-subunit, (ii) the formation of a bent oxo-bridged iron(III) species is essentially important in the L-subunit, and (iii) rich carboxyl groups in L-subunits contribute to facilitate iron nucleation and mineralization through the capture and activation of the peroxide ion, and formation of a stable bent oxo-bridged iron(III) species.