Dehydroascorbic acid reduction in several tissues and cultured hepatocytes of the chicken

Dehydroascorbic acid, the oxidized form of ascorbic acid, is rapidly reduced to ascorbate in living organs (ascorbate recycling). We examined the GSH-dependent dehydroascorbate reductase activity in several tissues of the chicken. The activity was highest in the liver, and second highest in the brain. The activity was localized in the cytosol fraction of the liver. We subsequently examined the dehydroascorbate reduction in separated chicken hepatocytes. The cellular ascorbate concentration was elevated in dehydroascorbate-treated cells. It is thought that hepatocytes incorporated external dehydroascorbate and converted it into ascorbate. These findings suggest that the liver plays an important role in ascorbate recycling by the chicken.

Effect of alkylpyrazine derivatives on the duration of pentobarbital-induced sleep, picrotoxicin-induced convulsion and gamma-aminobutyric acid (GABA) levels in the mouse brain

The effect of alkylpyrazine derivatives on pentobarbital-induced sleeping time, picrotoxicin-induced convulsion and gamma-aminobutyric acid (GABA) levels in mouse brain were studied. The duration of pentobarbital-induced sleep in mice was dose-dependently increased by 2,5-dimethylpyrazine (DMP). The duration of pentobarbital-induced sleep was also increased by an administration route of intracerebroventricular injection. Sleep duration was also increased by the administration of isomers of DMP, 2-chloro-3,6-dimethylpyrazine (DMP-Cl) and 2-fluoro-3,6-dimethylpyrazine (DMP-F), but 3,6-dimethylpyrazine-2-thiol (DMP-SH) did not affect sleep duration. The interval until the appearance of picrotoxicin-induced convulsion was prolonged by DMP and DMP-Cl. Increased sleep duration was obtained by administering DMP in combination with aminooxyacetic acid (AOAA) and diazepam compared to a single injection. The interval until convulsion due to picrotoxin was also prolonged by the administration of DMP combined with diazepam and valproic acid (VPA). The interval until the appearance of bicuculline-induced convulsion was also prolonged by pretreatment with DMP. The GABA level in mouse brain was increased by the administration of AOAA, VPA, DMP and DMP-Cl. These results suggest that DMP and other derivatives may strengthen the GABAnergic system in the brain.

Changes in ascorbic acid content in primary cultured rat hepatocytes exposed to 2,2'-azobis (2-amidinopropane) dihydrochloride, a radical initiator

Changes in ascorbate content in primary cultured rat hepatocytes exposed to oxidative stress derived from water soluble radical initiator 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) were examined. Cells were exposed to 0.05 and 5 mg/ml of AAPH as 'mild' and severe' oxidative stresses, respectively. Lipid peroxidation in hepatocytes was induced by 'severe' oxidative stress, but not by 'mild' oxidative stress. Ascorbate decreased at 6 hr after administration of both mild' and severe' oxidative stresses, and recovered to the control level after a further 6 hr. In cells treated with 'severe oxidative stress, however, total ascorbate (reduced form plus oxidized form) had increased 24 hr after administration. These results indicated that consumption alone did not account for the increase of ascorbate in hepatocytes under oxidative stress.

Evolution of fractal patterns during a classical-quantum transition

We investigate how fractals evolve into nonfractal behavior as the generation process is gradually suppressed. Fractals observed in the conductance of semiconductor billiards are of particular interest because the generation process is semiclassical and can be suppressed by transitions towards either fully classical or fully quantum-mechanical conduction. Investigating a range of billiards, we identify a "universal" behavior in the changeover from fractal to nonfractal conductance, which is described by a smooth evolution rather than deterioration in the fractal scaling properties.

Diagnosis of pancreatic adenocarcinoma by detection of human telomerase reverse transcriptase messenger RNA in pancreatic juice with sample qualification

PURPOSE

We evaluated the diagnostic efficacy of detection of human telomerase reverse transcriptase (hTERT) message, a catalytic domain of human telomerase, in endoscopic retrograde pancreatography (ERP)-derived pancreatic juice.

EXPERIMENTAL DESIGN

Both hTERT and CD25 expression were detected by reverse transcription-PCR (RT-PCR) in 17 patients with pancreatic adenocarcinoma (PC), 12 patients with chronic pancreatitis (CP), and 7 patients with no ERP abnormality (N). In the same patients, beta-actin message was semiquantified by competitive RT-PCR. K-ras codon 12 mutations were concomitantly analyzed by enriched PCR-SSCP in 11 and 7 PC and CP cases, respectively.

RESULTS

Expression of hTERT was detected in 88% of PC cases and 17% of CP cases but not in the normal control (N). Alterations in K-ras were detected in 73% of PC cases and 57% of CP cases, respectively. beta-Actin mRNA was expressed in >3.0 x 10(1) copies/microl in all but two PC cases in which hTERT mRNA was not detected. CD25-positive and -negative peripheral lymphocytes were isolated from a normal volunteer using a fluorescent activating cell sorter. The hTERT message was detected in CD25-positive peripheral lymphocytes and in 18, 25, and 0% of the pancreatic juice samples from PC, CP, and N cases, respectively. All CP cases expressing hTERT message were also CD25 positive.

CONCLUSIONS

These results suggest that detection of hTERT mRNA in pancreatic juice is a powerful tool to discriminate PC from CP, particularly when the samples are qualified against beta-actin mRNA levels and contaminating CD25-positive lymphocytes.

A fibronectin-binding protein from rice bran with cell adhesion activity for animal tumor cells

A rice bran 57-kDa protein was isolated by affinity chromatography with fibronectin immobilized on agarose. This fibronectin-binding protein designated as RB-57 had an amino-terminal amino acid sequence identical with that of a putative mature form of rice hydroxyproline-rich glycoprotein. A distinct feature of the amino acid composition of RB-57 was the high contents of hydroxyproline and proline representing about 45% of the total amino acids. The sugar analysis indicated that arabinose represented 46.8% of the total carbohydrates. RB-57 showed cell adhesion activity for murine Lewis lung carcinoma cells. The result suggests that RB-57 may play a role in plant cell adhesion, although cell adhesion-promoting activity for plant cells remains to be tested.

Stereocontrolled asymmetric synthesis of alpha-hydroxy-beta-amino acids. A stereodivergent approach

The stereocontrolled asymmetric synthesis of alpha-hydroxy-beta-amino acids has been investigated via the Lewis acid-promoted cyanation of (5R,6S)-2-acetoxy-4-(benzyloxycarbonyl)-5,6-diphenyl-2,3,5,6-tetrahydro-4H-1,4-oxazines with trimethylsilyl cyanide. Base-catalyzed hydrolysis of the resulting cyano compounds proceeds with excellent stereoselectivity, providing access to diastereomerically pure oxazine-2-carboxylic acids which were readily converted to each enantiomer of the alpha-hydroxy-beta-amino acids isothreonine and nor-C-statine.

X-ray-excited optical luminescence of impurity atom in semiconductor

We observed the x-ray-excited optical luminescence (XEOL) of erbium-doped silicon (Si:Er) thin films to make a site-selective x-ray absorption fine structure (XAFS) measurement of an optically active Er atom. The undulator beam was used for the increment of the electron population in the excited state, and following XEOL at an infrared wavelength of 1.54 microm with minimum absorption loss in the host Si was detected. The edge-jump and XAFS oscillation were successfully obtained at the Er L(III)-edge. This spectrum originated from inner-shell excitation and relaxation of only the optically active Er atom, indicating that site-selectivity at an atomic level was achieved.

Apoptosis-inducing activity of high molecular weight fractions of tea extracts

High molecular weight fractions of green tea, black tea, oolong tea, and pu-erh tea were found to induce apoptosis in human monoblastic leukemia U937 cells by examination of their ability to inhibit cell proliferation and to induce apoptotic body formation and DNA ladder formation. These tea fractions were also shown to induce apoptosis in stomach cancer MKN-45 cells. In addition to known antitumor-promoting activity of tea high molecular weight fractions, their apoptosis-inducing activity may contribute to cancer chemopreventive effects of tea.

[Estimation of daily dietary intake of aluminum]

The daily dietary intake of aluminum was estimated through a total diet study from 1996 to 1998. In ten institutes, total diet study samples were prepared and their aluminum concentration was determined. The average daily intake of aluminum was 3.5 mg and the range was 1.8-8.4 mg. The validity of the analytical result was supported by analyses of certified reference materials.

Hepatic fatty acid-binding proteins of a teleost, Lateolabrax japonicus. The primary structures and location of a disulfide bond

Two fatty acid-binding proteins (FABP), FABP-1 and FABP-2, were purified from the liver cytosol of the teleost, Lateolabrax japonicus (Japan sea bass), and characterized. The complete primary structure of FABP-2 was determined by protein analysis to be the following: MDFSGTWQVY AQENYEEFLR AMELPADVIK MAKDIKPITE IKQSGNDFVV TSKTPGKTVT NSFTIGKEAD ITTMDGKKIR CVVNLEGGKL VCNTGKFCHI QELRGGEMVE TLTMGSTTLI RKSKKM. Partial peptide sequences of FABP-1 were also determined. Phylogenetic analysis indicates that FABP-2 is a homologue of mammalian hepatic FABP, whereas FABP-1 is most similar to the members of mammalian cardiac FABP subfamily. L. japonicus FABP-2 contains three cysteine residues, and a disulfide bond is identified between Cys-81 and Cys-92. A theoretical model of FABP-2 generated by a homology modeling method indicates close proximity of the two cysteine residues in the three-dimensional structure. This is a rather rare case of cytosolic protein having a disulfide bond under the normally reducing conditions of the cytosol, though the presence or absence of disulfide bonds does not seem to affect the ligand-binding ability.

Synthesis of the novel analogues of dysidiolide and their structure-activity relationship

The novel analogues of natural cdc25A inhibitor dysidiolide were synthesized. To investigate the structure-activity relationship, the inhibitory activity to enzyme and cell cycle was examined.

[Syntheses of biologically active natural products using metal-mediated reactions as key reactions]

This review deals with total syntheses of biologically active natural products by the use of metal-mediated coupling reactions as key steps. First, we explored the coupling reactions mediated by samarium (II) diiodide (SmI2), which is a useful versatile one electron reducing reagent. The SmI2-mediated coupling reactions of N,N-dibenzyl-alpha-bromoamide and N,N-bis(p-methoxyphenyl)-alpha-bromoamide with carbonyl compounds gave the corresponding beta-hydroxyamides, respectively. Then, oxidative treatment of compound 6c with ceric (IV) ammonium nitrate (CAN) gave d,l-myrmicacine (7b). Synthesis of pyrrolizidine alkaloid pyrrolam A (8), which causes damage to fertilized eggs at a low concentration, was accomplished via the SmI2-mediated cyclization between a bromoalkyl and ynamide group. Next, (+/-)-oxerine (15), a monoterpene alkaloid, was synthesized starting from 3-bromopyridine. The synthesis of (+/-)-oxerine (15) was also carried out via the SmI2-mediated intramolecular cyclization of gamma-ethynyl bromide (40). Next, we focused on the palladium-catalyzed oxidation of alcohol and tried to expand it to the intermolecular cyclization. As a result, treatment of hydroxy-enamines and hydroxy-amines with a palladium catalyst gave the corresponding pyrroles and indoles in moderate to good yields. Finally, the syntheses of three pyrrolidine alkaloids were described. The chromium (II) chloride-mediated coupling reactions of (R)- and (S)-Garner aldehydes (56 and 57) with allyl bromides proceeded with moderate stereoselectivity to afford the corresponding homoallyl alcohols, which were converted to (2R, 3S)-2-hydroxymethyl-3-hydroxypyrrolidine (61), (2R, 3R, 4R)-3-hydroxy-4-methylproline (66), and the enantiomer (77) of (-)-bulgecinine (78).

Pharmacological effects of urinary products obtained after treatment with saiboku-to, a herbal medicine for bronchial asthma, on type IV allergic reaction

To define the anti-allergic components in Saiboku-To, a herbal medicine for bronchial asthma, we examined the effects of 11 compounds found in post-administrative urine of Saiboku-To on concanavalin A-induced human lymphocyte blastogenesis in vitro and picryl chloride (PC)-induced mouse ear swelling in vivo. The urinary products of Saiboku-To were flavonoids and lignans derived from the constitutional herbs and their hydrogenated metabolites. Medicarpin derived from Glycyrrhiza glabra, magnolol and 8,9-dihydroxydihydromagnolol from Magnolia officinalis, baicalein, wogonin and oroxylin A from Suctellaria baicalensis inhibited lymphocyte blastogenesis in dose-dependent fashion with IC50 values ranging from 3.0 to 7.7 micrograms/mL, which corresponded to 20-100 times that of prednisolone IC50 (0.08 microgram/mL). Davidigenin, dihydrowogonin and dihydrooroxylin A, which are hydrogenated metabolites of liquiritigenin, wogonin and oroxylin A, respectively, had no or little effects on lymphocyte blastogenesis. Oral administration of Saiboku-To, medicarpin, baicalein, magnolol and baicalin (100 mg/kg), inhibited PC-induced ear swelling significantly by 23.5, 40.1, 30.5, 23.6 and 20.9%, respectively, though the effects were weaker than that of 5 mg/kg of prednisolone (52.9%). The results suggested that flavonoids and lignans tested in the present study were implicated in anti-asthmatic effect of Saiboku-To through suppression of type IV allergic reaction.

Expanded polyglutamine stretches interact with TAFII130, interfering with CREB-dependent transcription

At least eight inherited neurodegenerative diseases are caused by expanded CAG repeats encoding polyglutamine (polyQ) stretches. Although cytotoxicities of expanded polyQ stretches are implicated, the molecular mechanisms of neurodegeneration remain unclear. We found that expanded polyQ stretches preferentially bind to TAFII130, a coactivator involved in cAMP-responsive element binding protein (CREB)-dependent transcriptional activation, and strongly suppress CREB-dependent transcriptional activation. The suppression of CREB-dependent transcription and the cell death induced by polyQ stretches were restored by the co-expression of TAFII130. Our results indicate that interference of transcription by the binding of TAFII130 with expanded polyQ stretches is involved in the pathogenetic mechanisms underlying neurodegeneration.

The induction of apoptosis and inhibition of AP-1 activity by TAC-101 (4-[3,5-bis(trimethylsilyl) benzamido] benzoic acid) may result in life prolonging effect in animals bearing metastasizing cancer

BACKGROUND

The incidence of cancers of the digestive tract has been high among all of the cancers in Japan and the western hemisphere. The poor prognosis of patients, especially those with liver metastases, has become a great challenge for the development of a new drug to cope with this problem.

MATERIALS AND METHODS

Mice implanted by intrasplenic injection of TMK-1, human gastric carcinoma cells, were used to examine the life-prolonging effect of TAC-101. To elucidate a mechanism of action of TAC-101, the drug-induced apoptosis was assessed by DNA ladder formation whilst the prevention of transcription factor AP-1 binding to its DNA recognition sequence was assessed by gel shift assay.

RESULTS

TAC-101 showed the life prolonging effect in a model of experimental liver metastasis of TMK-1. The antitumor effect, expressed as T/C (%), was 201, 141 and 112%, for TAC-101 (2 mg/kg), ATRA (8 mg/kg) and 5-FU (19 mg/kg), respectively. The in vitro experiments revealed that the anticancer activity of TAC-101 is related to its ability to induce apoptosis within a short period of time in TMK-1 cells and human leukemic cells, HL-60. TAC-101-induced apoptosis was suppressed by the inhibitors of proteases, specifically by Z-Val-Ala-DL-Asp-fluoromethylketone, indicating the involvement of caspase activation. TAC-101 also inhibited, in a concentration-dependent manner, the binding of AP-1 to its DNA binding sites present in the promoter region of the genes involved in the control of cell migration, invasion, and angiogenesis.

CONCLUSION

TAC-101 may suppress liver metastasis by the induction of an apoptotic mechanism(s) in cancer cells and possibly by controlling transcriptional activity of AP-1.

Anticancer effect of 4-[3,5-bis(trimethylsilyl)benzamido] benzoic acid (TAC-101) against A549 non-small cell lung cancer cell line is related to its anti-invasive activity

We examined the effects of TAC-101 on the invasion and metastasis of human non-small cell lung cancer (NSCLC) cell lines. TAC-101 showed an ability to inhibit in vitro invasiveness of NSCLC at a non-cytotoxic concentration range of 3-10 microM; such concentration levels were easily achievable following oral administration of therapeutically effective doses. The inhibition of cell invasion at 10 microM of TAC-101 accounted for 58-69% when compared with control cells. Oral administration of TAC-101 (4 mg/kg/day) to mice bearing lung implanted A549 lung cancer resulted in significant life-prolonging effect (T/C: 143%). More pronounced life-prolonging effect was observed in the experimental liver metastasis model of A549, where T/C of 215% was observed following administration at 4 mg/kg/day of TAC-101. However, TAC-101 did not show the direct anti-tumor effect against the established A549 tumor xenografts after subcutaneous implantation. These findings suggest that TAC-101 interferes with cell-to-cell interaction processes leading, for instance, to the inhibition of the invasion of NSCLC cells. Taking into account the pharmacological properties of TAC-101, it is expected that TAC-101 may be a suitable candidate drug for the treatment of lung cancer patients, especially those with a predictable metastasizing potential.

Ascorbic acid supplementation to primary culture of chicken hepatocytes with non-serum medium

Chicken liver is lack of ascorbic acid biosynthesis system, different from mammals and highly evoluted birds. Chicken hepatocytes cultured without ascorbate was expected to have lower ascorbate amounts than physiological levels. Intracellular was decreased as compared with intact liver by cell preparation performed with in situ collagenase perfusion. We added ascorbate to a primary culture of chicken hepatocytes in order to restore the amount of ascorbate. Serum-free Leivobitz's L-15 medium which do not contain ascorbate was used for control medium. Cells were cultured with several concentrations of ascorbate for 24 or 48 h. After ascorbate supplementation for 24 to 48 h, cellular ascorbate concentration increased depending on the dose of medium ascorbate. Medium lactate dehydrogenase activity derived from hepatocytes, an index of cell injury, decreased upon 5-100 mg/l of ascorbate supplementation for 48 h. Tyrosine aminotransferase activity, an index of liver function, increased following culture with 50 and 100 mg/l ascorbate for 48 h. The activities, however, decreased by supplementation with 1000 mg/l of ascorbate. In conclusion hepatocytes lost intracellular ascorbate during preparation by in situ collagenase perfusion. Supplementation of ascorbate restored cellular ascorbate concentration, lowered cell injury and raised tyrosine aminotransferase activitv in primary cultured chicken hepatocytes. Ascorbate treatment for 48 h at 50 mg/l was the best combination in this study for primary culture of chicken hepatpcyte with non-serum L-15 medium

Use of the collision technique to improve the accuracy of motor unit number estimation

OBJECTIVE

To evaluate the risk of stimulating the same motor axon at different points along the median nerve when using the multiple point stimulation (MPS) technique and how this affects the accuracy of the motor unit number estimate (MUNE).

METHODS

Using the MPS technique, MUNE in the median innervated intrinsic hand muscles was done on two normal subjects, a patient with carpal tunnel syndrome and one with prior poliomyelitis. The collision technique was then used to confirm whether two motor unit action potentials (MUAPs) with similar configurations and sizes were generated by the same motor unit. A new MUNE was recalculated after the repeated inclusion of the same motor unit had been excluded.

RESULTS

While the risk of stimulating the same motor axon at widely separate locations of the median nerve was negligible in normal subjects, this risk was much higher in patients with a depleted motor neuron pool. This resulted in marked distortion of the calculated size of the average single MUAP and, consequently, inaccuracy of the MUNE.

CONCLUSIONS

The inadvertent inclusion of the same motor units, if not recognized, can markedly affect the accuracy of the MUNE. The collision technique can be useful in minimizing this risk.