The protein Ocular albinism 1 is the orphan GPCR GPR143 and mediates depressor and bradycardic responses to DOPA in the nucleus tractus solitarii.

BACKGROUND AND PURPOSE: L-DOPA is generally considered to alleviate the symptoms of Parkinson's disease by its conversion to dopamine. We have proposed that DOPA is itself a neurotransmitter in the CNS. However, specific receptors for DOPA have not been identified. Recently, the gene product of ocular albinism 1 (OA1) was found to exhibit DOPA-binding activity. Here, we have investigated whether OA1 is a functional receptor of DOPA in the nucleus tractus solitarii (NTS). EXPERIMENTAL APPROACH: We examined immunohistochemical expression of OA1 in the NTS, and the effects of DOPA microinjected into the depressor sites of NTS on blood pressure and heart rate in anaesthetized rats, with or without prior knock-down of OA1 in the NTS, using shRNA against OA1. KEY RESULTS: Using a specific OA1 antibody, OA1-positive cells and nerve fibres were found in the depressor sites of the NTS. OA1 expression in the NTS was markedly suppressed by microinjection into the NTS of adenovirus vectors carrying the relevant shRNA sequences against OA1. In animals treated with OA1 shRNA, depressor and bradycardic responses to DOPA, but not those to glutamate, microinjected into the NTS were blocked. Bilateral injections into the NTS of DOPA cyclohexyl ester, a competitive antagonist against OA1, suppressed phenylephrine-induced bradycardic responses without affecting blood pressure responses. CONCLUSION AND IMPLICATIONS: OA1 acted as a functional receptor for DOPA in the NTS, mediating depressor and bradycardic responses. Our results add to the evidence for a central neurotransmitter role for DOPA, without conversion to dopamine.

Putative occurrence of lysine decarboxylase isoforms in soybean (Glycine max) seedlings.

The activity of lysine decarboxylase was studied in 3-day-old soybean (Glycine max (L.) Meer cv. Sakai) seedlings also in relation to light conditions. Lysine decarboxylase activity was mainly localized in the roots and to a lesser extent in the hypocotyls and was detectable in both the soluble and particulate fractions. The enzyme activity levels were similar during germination under light and dark conditions. With respect to lysine concentration, the initial decarboxylation rate of the soluble fraction showed a saturating curve. Conversely, the initial decarboxylation rate of the particulate fraction showed a sigmoidal curve. These results could suggest that at least two isoforms of lysine decarboxylase are present in different organs of soybean seedlings. In the root soluble fraction, the suicide inhibitor alpha-difluoromethyl-lysine suppressed the activity of lysine decarboxylase and of ornithine decarboxylase to the same extent, but had no effect on arginine decarboxylase activity.

A novel DISC1-interacting partner DISC1-Binding Zinc-finger protein: implication in the modulation of DISC1-dependent neurite outgrowth.

Disrupted-in-schizophrenia 1 (DISC1) is a gene disrupted by a (1;11) (q42.1;q14.3) translocation that segregates with major psychiatric disorders in a Scottish family. To investigate how DISC1 confers susceptibility to psychiatric disorders, we previously identified fasciculation and elongation protein zeta-1 and Kendrin as DISC1-interacting molecules in a yeast two-hybrid screen of a human brain complementary DNA library. Here, we have further identified a novel DISC1-interacting protein, termed DISC1-Binding Zinc-finger protein (DBZ), which has a predicted C(2)H(2)-type zinc-finger motif and coiled-coil domains. DBZ was co-immunoprecipitated with DISC1 in lysates of PC12 cells and rat brain tissue. The domain of DISC1 interacting with DBZ was close to the translocation breakpoint in the DISC1 gene. DBZ messenger RNA (mRNA) was expressed in human brains, but not in peripheral tissues. In situ hybridization revealed high expression of DBZ mRNA in the hippocampus, olfactory tubercle, cerebral cortex and striatum in rats. Because this pattern of localization was similar to that of the pituitary adenylate cyclase (PAC(1)) receptor for pituitary adenylate cyclase-activating polypeptide (PACAP), which has recently been implicated in neuropsychological functions, we examined whether DISC1/DBZ interaction was involved in the PACAP signaling pathway. PACAP upregulated DISC1 expression and markedly reduced the association between DISC1 and DBZ in PC12 cells. A DISC1-binding domain of DBZ reduced the neurite length in PC12 cells after PACAP stimulation and in primary cultured hippocampal neurons. The present results provide some new molecular insights into the mechanisms of neuronal development and neuropsychiatric disorders.

Secretory IgA, salivary peroxidase, and catalase-mediated microbicidal activity during hydrogen peroxide catabolism in viridans streptococci: pathogen coaggregation.

Viridans streptococci can kill methicillin-resistant Staphylococcus aureus (MRSA) through the production of hydrogen peroxide (H2O2). However, several hundred viridans streptococci cells are necessary to kill 1 cfu of MRSA. We analyzed the potency of bactericidal and fungicidal effector molecules induced by catabolism of H2O2 in the oral cavity. Secretory IgA (SIgA) and an unidentified salivary component bound Streptococcus sanguinis, a viridans streprococcus, and MRSA into coaggregates. In these coaggregates, salivary peroxidase and the MRSA catalase produced singlet molecular oxygen (1O2) from H2O2 produced by viridans streptococci. SIgA converted 1O2 into ozone, which has potent bactericidal and fungicidal activity. We calculated that <10 cfu of Streptococcus sanguinis were necessary to kill 1 cfu of MRSA in the coaggregate. SIgA, Aspergillus niger catalase, and H2O2 in saliva killed Candida albicans, which is highly resistant to reagent H2O2. Together with indigenous bacteria and innate immunity, SIgA potentially constitutes a novel system that may sustain oral homeostasis.

Suppressive effect of active hexose correlated compound (AHCC) on thymic apoptosis induced by dexamethasone in the rat.

OBJECTIVE: Mushroom extracts are known to have immunomodulating and antitumor effects in humans as well as in animals. In the present study Active Hexose Correlated Compound (AHCC), an extract obtained from several kinds of basidiomycetes was examined for its suppressive effect on thymocyte apoptosis induced by dexamethasone. METHOD: Thymic apoptosis was evaluated by gel electrophoresis and by flow cytometry at 3 h after injection of dexamethasone to rats. RESULTS: When given to rats at 4 % concentration in drinking water for more than 4 days, AHCC suppressed the internucleosomal DNA fragmentation in the thymus induced by dexamethasone. Flow cytometry also revealed that thymic apoptosis induced by dexamethasone was prevented by pretreatment with AHCC. Dexamethasone increased the caspase 3-like activity within 3 h after its treatment and AHCC pretreatment suppressed the increased enzyme activity only slightly. No apparent increase in serum levels of melatonin and interleukin 1beta was observed after AHCC treatment. CONCLUSIONS: These results suggest that AHCC exhibits immuno-modulating effects at least partially by regulating thymic apoptosis.

Chemosensitivity test is useful in evaluating the appropriate adjuvant cancer chemotherapy for stage III non-scirrhous and scirrhous gastric cancers.

A total of 183 cases with gastric cancer was retrospectively analyzed in terms of their chemosensitivity as determined by the 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl-2H tetrazolium bromide (MTT) assay and their survival rates after surgery. After the patients were stratified into scirrhous or non-scirrhous carcinoma groups, they were tested for stage III or IV gastric cancer. In these four cohorts, the patients were categorized into sensitive and insensitive groups determined by the MTT assay. The sensitive group was treated with at least one drug that had been shown to be effective in the MTT assay, and the insensitive group was given a drug that had been shown to be ineffective in the MTT assay. In stage III gastric cancer, the sensitive group showed a favorable survival compared to the insensitive group in scirrhous and non-scirrhous carcinoma, while this difference was diminished in stage IV gastric cancer. There were no survival benefits in the sensitive group in stage III gastric cancer, when they were not treated with adjuvant cancer chemotherapy. These results suggested that MTT assay would be useful in evaluating the appropriate adjuvant cancer chemotherapy for stage III scirrhous and non-scirrhous gastric cancer.

Further evidence for the value of the chemosensitivity test in deciding appropriate chemotherapy for advanced gastric cancer.

BACKGROUND: The chemosensitivity test using the MTT endpoint is useful in predicting chemosensitivity. PATIENTS AND METHODS: One hundred twenty-eight patients with advanced gastric cancer were enrolled in the study, which mitomycin C (MMC), doxorubicin (DXR), 5-fluorouracil (5-FU), and cisplatin (DDP) were used. RESULTS: The corresponding efficacy rates were 12.5% for MMC, 6.3% for DXR, 5.4% for 5-FU and 13.4% for DDP. The overall predictive accuracy was 78% in the patients with measurable lesions. Among the patients without measurable lesions, 21 were treated with a curative operation, and 33 with a non-curative operation. In those patients undergoing curative surgery, the "adapted" group detected by MTT assay survived longer than "non-adapted" cases (p < 0.05). CONCLUSIONS: The present study provides further evidence that the chemosensitivity test may be useful for evaluating appropriate chemotherapy for advanced gastric cancer.

Alpha-tocopherol and superoxide dismutase suppress and diethyldithiocarbamate and phorone enhance the lipopolysaccharide-induced increase in N1-acetylspermidine concentrations in mouse liver.

Previously, we have shown the close association between hepatic concentrations of N1-acetylspermidine and the radical-producing potency of several drugs. Since vitamin E, superoxide dismutase (SOD), and reduced glutathione (GSH) are known to scavenge free radicals, in this study we tested the effect of alpha-tocopherol, one of the most potent vitamin E isomers, and SOD on the lipopolysaccharide (LPS)-induced increase in hepatic concentrations of N1-acetylspermidine. The LPS-induced increase in hepatic N1-acetylspermidine was more than twice as great in vitamin E-deficient mice as in vitamin E-supplemented mice. Pretreatment with alpha-tocopherol suppressed the LPS-induced increase in hepatic N1-acetylspermidine in vitamin E-deficient mice. Alpha-tocopherol and SOD given to mice maintained on a usual diet likewise suppressed the LPS-induced increase in hepatic N1-acetylspermidine and putrescine. The hepatic concentrations of alpha-tocopherol and GSH were lower in LPS-treated mice than in control animals. Diethyldithiocarbamate, an inhibitor of SOD, and diisopropylidene (phorone), a GSH-depleting agent, enhanced the LPS-induced increase in hepatic N1-acetylspermidine. These results suggest that the LPS-induced hepatic increase in N1-acetylspermidine is connected with radical-induced injury in vivo and that superoxide anion is produced in the liver of LPS-treated mice.

Detection and chemical identification of natural bio-antimutagens. A case of the green tea factor.

A bio-antimutagen, isolated from Japanese green tea (leaves of Camellia sinensis), reduced high spontaneous mutations due to altered DNA-polymerase III in a mutator strain of Bacillus subtilis. Chemical studies showed that the factor was epigallo-catechin-gallate (EGCg).

Natural occurrence of guanidinooxypropylamine in Wistaria floribunda and the sword bean Canavalia gladiata.

We found a new guanidinooxyamine in Wistaria floribunda seeds and seedlings of the sword bean, Canavalia gladiata. This amine was not only ninhydrin-positive but also gave a positive alkaline nitroprusside-ferricyanide reaction. It was characterized as gamma-guanidinooxypropylamine [H2N (NH=)CNHO (CH2)3NH2] by comparison with the authentic compound on column and thin-layer chromatograms visualized with specific reagents and by reductive cleavage. Evidence for the occurrence of another unusual guanidino amine, homoagmatine in W. floribunda seeds was also presented.

Duplication of the caecum in a neonate simulating intussusception.

A case of caecal duplication in a 36-h-old neonate is described. The patient presented with vomiting and an abdominal mass and the barium enema finding was initially suggestive of intussusception. At laparotomy a duplication cyst completely obstructing the lumen was found. This was considered to have given the radiological picture simulating intussusception.