Construction of YAC-based mammalian artificial chromosomes

To construct a mammalian artificial chromosome (MAC), telomere repeats and selectable markers were introduced into a 100 kb yeast artificial chromosome (YAC) containing human centromeric DNA. This YAC, which has a regular repeat structure of alpha-satellite DNA and centromere protein B (CENP-B) boxes, efficiently formed MACs that segregated accurately and bound CENP-B, CENP-C, and CENP-E. The MACs appear to be about 1-5 Mb in size and contain YAC multimers. Structural analyses suggest that the MACs have not acquired host sequences and were formed by a de novo mechanism. The accurate segregation of the MACs suggests they have potential as vectors for introducing genes into mammals.

Increased generation of reactive oxygen species in embryos cultured in vitro

Previous studies have suggested that oxygen toxicity is closely related to the developmental blockage of embryos cultured in vitro. In this study, to obtain an actual proof of the increase in production of reactive oxygen species within embryos, we have measured the level of H2O2 in individual embryos using a fluorimetric method. Mouse (ICR) pronuclear stage embryos from the oviducts were cultured for a specified time under various conditions in a medium to which 2',7'-dichlorodihydrofluorescin diacetate was added. After washing the embryos, the fluorescence emissions of the H2O2-dependent oxidative product in embryos were measured. The fluorescent emissions were lowest in embryos cultured under 5% O2 and highest under 40% O2 (5% < 20% < 40%), just the inverse of the culture efficacy. The fluorescence emmissions of embryos cultured in Ham's F-10, which contains hypoxanthine and transition metals such as Cu and Fe, were higher than those cultured in BWW and alpha MEM, which do not contain these components (alpha MEM < BWW < Ham's F-10; again this is the inverse of the culture efficacy). The fluorescence emissions of embryos increased with the time of the exposure to visible light. L-cysteine and thioredoxin, both of which have been shown to promote embryo development, decreased the fluorescence emissions of embryos. All of these results would provide direct evidence for the hypothesis that oxygen radicals are involved in the developmental blockage.

Rapid translocation frequency analysis in humans decades after exposure to ionizing radiation

This paper presents an analysis of the utility of fluorescence in situ hybridization (FISH) with whole-chromosome probes for measurement of the genomic frequency of translocations found in the peripheral blood of individuals exposed to ionizing radiation. First, we derive the equation: Fp = 2.05fp(1-fp)FG, relating the translocation frequency, Fp, measured using FISH to the genomic translocation frequency, FG, where fp is the fraction of the genome covered by the composite probe. We demonstrate the validity of this equation by showing that: (a) translocation detection efficiency predicted by the equation is consistent with experimental data as fp is changed; (b) translocation frequency dose-response curves measured in vitro using FISH agree well with dicentric frequency dose-response curves measured in vitro using conventional cytogenetic procedures; and (c) the genomic translocation frequencies estimated from FISH measurements for 20 Hiroshima A-bomb survivors and four workers exposed to ionizing radiation during the Y-12 criticality accident are approximately the same as the translocation frequencies measured using G-banding. We also show that translocation frequency dose response curves estimated using FISH are similar for Hiroshima A-bomb survivors and for first division lymphocytes irradiated in vitro. We conclude with a discussion of the potential utility of translocation frequency analysis for assessment of the level of acute radiation exposure independent of the time between analysis and exposure.

Estrogens as natural antioxidants of membrane phospholipid peroxidation

Estrogens, such as estrone, estradiol and estriol, were tested as possible antioxidants of lipid peroxidation induced by Fe3+-ADP-adriamycin or Fe3+-ADP-ascorbate. The estrogens with phenolic structure possessed substantial activities with respect to the inhibition of lipid peroxidation. Concentrations of estradiol and estriol required to achieve 50% inhibition of membrane phospholipid peroxidation were about 4- and 6-times that of alpha-tocopherol, respectively.

Tumor necrosis factor-alpha provokes a hypertrophic growth response in adult cardiac myocytes

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha) is a pleiotropic cytokine with a broad range of concentration-dependent effects. The recent observation that TNF-alpha is expressed by the cardiac myocyte after certain forms of stress suggests that TNF-alpha might contribute to the maintenance of normal tissue homeostasis after environmental injury. Accordingly, the purpose of this study was to examine the effects of TNF-alpha on protein synthesis in cultured adult cardiac myocytes.

METHODS AND RESULTS

Cultured adult feline cardiac myocytes were stimulated with 10 to 1000 U/mL TNF-alpha to examine the effects of this cytokine on the rate of protein synthesis and degradation. Stimulation with TNF-alpha led to an accelerated rate of general protein synthesis and a time-dependent decrease in protein degradation in adult cardiac myocytes. The specificity of these findings was demonstrated by studies in which the effects of TNF-alpha on protein synthesis were blocked by a neutralizing anti-TNF-alpha antibody as well as studies in which TNF-alpha-conditioned medium had no effect on protein synthesis in myocytes. In addition to the TNF-alpha-induced increase in the general protein synthesis, stimulation with TNF-alpha led to a 2.4-fold increase in net actin protein synthesis and a 3.3-fold increase in net myosin heavy chain synthesis. Finally, the effects of TNF-alpha on adult cardiac myocytes were shown to be dependent on cell-substrate interaction, suggesting that the cell signaling pathways used by TNF-alpha are dependent on a preserved interaction between cell integrins and the extracellular matrix.

CONCLUSIONS

The observation that TNF-alpha provokes a hypertrophic growth response in cardiac myocytes suggests that TNF-alpha may play an important role in myocardial homeostasis after environmental stress.

Chemiluminescence probe with Cypridina luciferin analog, 2-methyl-6-phenyl-3,7-dihydroimidazo[1,2-a]pyrazin-3-one, for estimating the ability of human granulocytes to generate O2-

The Cypridina luciferin analog, 2-methyl-6-phenyl-3,7-dihydroimidazo[1,2-a]pyrazin-3-one (CLA), in Hanks' balanced salt solution, emitted a weak luminescence which was not affected by superoxide dismutase or catalase and was not augmented by resting human granulocytes. In contrast, activated granulocytes caused a dramatic increase in the luminescence of CLA. The light emission by CLA in the presence of activated granulocytes was inhibited by superoxide dismutase, but not by catalase or benzoate. Azide at 0.5 mM did not inhibit light emission significantly. These results indicate that O2-, rather than H2O2, HO., singlet oxygen, or HOCl, was the agent responsible for eliciting the chemiluminescence of CLA. Moreover, the intensity of light emission by CLA correlated with the rate of production of O2- either by activated neutrophils or by the xanthine oxidase reaction.

Hemodynamic regulation of tumor necrosis factor-alpha gene and protein expression in adult feline myocardium

Tumor necrosis factor-alpha (TNF-alpha) mRNA and protein biosynthesis were examined in adult feline myocardium in the presence and absence of superimposed hemodynamic pressure overloading. A brief period of hemodynamic pressure overloading ex vivo resulted in de novo TNF-alpha mRNA expression within 30 minutes and de novo TNF-alpha protein production within 60 minutes; neither TNF-alpha mRNA nor protein was detected in hearts perfused at normal perfusion pressures. Moreover, TNF-alpha mRNA and protein biosynthesis were observed in myocyte and nonmyocyte cell types in the pressure-overloaded hearts. To determine whether a simple passive stretch of the myocardium was a sufficient stimulus for TNF-alpha biosynthesis, we examined TNF-alpha mRNA expression in stretched and unstretched papillary muscles. This study showed that myocardial stretch was a sufficient stimulus for the induction of TNF-alpha mRNA biosynthesis. The functional significance of the intramyocardial production of TNF-alpha was determined by examining cell motion in isolated contracting cardiac myocytes treated with superfusates from pressure-overloaded and control hearts. These studies showed that cell motion was depressed in myocytes treated with superfusates from the pressure-overloaded hearts but was normal with the superfusates from the control hearts. Finally, hemodynamic pressure overloading in vivo under physiological conditions was also shown to result in de novo intramyocardial TNF-alpha mRNA biosynthesis. In conclusion, this study constitutes the initial demonstration that the adult mammalian myocardium elaborates biologically active TNF-alpha, both ex vivo and in vivo, in response to hemodynamic pressure overloading.

Quantitative study of bite force during sleep associated bruxism

Nocturnal bite force during sleep associated bruxism was measured in 10 subjects. Hard acrylic dental appliances were fabricated for the upper and lower dentitions of each subject. Miniature strain-gauge transducers were mounted to the upper dental appliance at the right and left first molar regions. In addition, thin metal plates that contact the strain-gauge transducers were attached to the lower dental appliance. After a 1-week familiarization with the appliances, nocturnal bite force was measured for three nights at the home of each subject. From the 30 recordings, 499 bruxism events that met the definition criteria were selected. The above described system was also used to measure the maximum voluntary bite forces during the daytime. The mean amplitude of detected bruxism events was 22.5 kgf (s.d. 13.0 kgf) and the mean duration was 7.1 s (s.d. 5.3 s). The highest amplitude of nocturnal bite force in individual subjects was 42.3 kgf (15.6-81.2 kgf). Maximum voluntary bite force during the daytime was 79.0 kgf (51.8-99.7 kgf) and the mean ratio of nocturnal/daytime maximum bite force was 53.1% (17.3-111.6%). These data indicate that nocturnal bite force during bruxism can exceed the amplitude of maximum voluntary bite force during the daytime.

Single-molecule magnets: a new class of tetranuclear manganese magnets

The preparation, X-ray structure, and detailed physical characterization are presented for a new type of single-molecule magnet [Mn4(O2CMe)2(pdmH)6](ClO4)2 (1). Complex 1.2MeCN.Et2O crystallizes in the triclinic space group P1, with cell dimensions at 130 K of a = 11.914(3) A, b = 15.347(4) A, c = 9.660(3) A, alpha = 104.58(1) degree, beta = 93.42(1) degree, gamma = 106.06(1) degree, and Z = 1. The cation lies on an inversion center and consists of a planar Mn4 rhombus that is mixed-valent, MnIII2MnII2. The pdmH- ligands (pdmH2 is pyridine-2,6-dimethanol) function as either bidentate or tridentate ligands. The bridging between Mn atoms is established by either a deprotonated oxygen atom of a pdmH- ligand or an acetate ligand. The solvated complex readily loses all acetonitrile and ether solvate molecules to give complex 1, which with time becomes hydrated to give 1.2.5H2O. Direct current and alternating current magnetic susceptibility data are given for 1 and 1.2.5H2O and indicate that the desolvated complex has a S = 8 ground state, whereas the hydrated 1.2.5H2O has a S = 9 ground state. Ferromagnetic interactions between MnIII-MnII and MnIII-MnIII pairs result in parallel spin alignments of the S = 5/2 MnII and S = 2 MnIII ions. High-frequency EPR spectra were run for complex 1.2.5H2O at frequencies of 218, 328, and 436 GHz in the 4.5-30 K range. A magnetic-field-oriented polycrystallite sample was employed. Fine structure is clearly seen in this parallel-field EPR spectrum. The transition fields were least-squares-fit to give g = 1.99, D = -0.451 K, and B4 degrees = 2.94 x 10(-5) K for the S = 9 ground state of 1.2.5H2O. A molecule with a large-spin ground state with D < 0 can function as a single-molecule magnet, as detected by techniques such as ac magnetic susceptibility. Out-of-phase ac signals (chi'' M) were seen for complexes 1 and 1.2.5H2O to show that these complexes are single-molecule magnets. A sample of 1 was studied by ac susceptibility in the 0.4-6.4 K range with the ac field oscillating at frequencies in the 1.1-1000 Hz range. A single peak in chi'' M vs temperature plots was seen for each frequency; the temperature of the chi'' M peak varies from 2.03 K at 995 Hz to 1.16 K at 1.1 Hz. Magnetization relaxation rates were evaluated in this way. An Arrhenius plot gave an activation energy of 17.3 K, which, as expected, is less than the 22.4 K value calculated for the thermodynamic barrier for magnetization direction reversal for an S = 8 complex with D = -0.35 K. The 1.2.5H2O complex with an S = 9 ground state has its chi'' M peaks at higher temperatures.

Mixed-valence tetranuclear manganese single-molecule magnets

The preparations, X-ray structures, and detailed physical characterizations are presented for two new mixed-valence tetranuclear manganese complexes that function as single-molecule magnets (SMM's): [Mn4(hmp)6Br2(H2O)2]Br2-4H2O (2) and [Mn4(6-me-hmp)6Cl4]-4H2O (3), where hmp(-) is the anion of 2-hydroxymethylpyridine and 6-me-hmp(-) is the anion of 6-methyl-2-hydroxymethylpyridine. Complex 2-4H2O crystallizes in the space group P2(1)/c, with cell dimensions at -160 degrees C of a = 10.907(0) A, b = 15.788(0) A, c = 13.941(0) A, beta = 101.21(0) degrees, and Z = 2. The cation lies on an inversion center and consists of a planar Mn4 rhombus that is mixed-valence, Mn2(III)Mn2(II). The hmp(-) ligands function as bidentate ligands and as the only bridging ligands in 2-4H2O. Complex 3-4H2O crystallizes in the monoclinic space group C2/c, with cell dimensions at -160 degrees C of a = 17.0852(4) A, b = 20.8781(5) A, c = 14.835(3) A, beta = 90.5485(8) degrees, and Z = 4. This neutral complex also has a mixed-valence Mn2(III)Mn2(II) composition and is best described as having four manganese ions arranged in a bent chain. A mu2-oxygen atom of the 6-me-hmp(-) anion bridges between the manganese ions; the Cl(-) ligands are terminal. Variable-field magnetization and high-frequency and -field EPR (HFEPR) data indicate that complex 2-4H2O has a S = 9 ground state whereas complex 3.4H(2)O has S = 0 ground state. Fine structure patterns are seen in the HFEPR spectra, and in the case of 2.4H(2)O it was possible to simulate the fine structure assuming S = 9 with the parameters g = 1.999, axial zero-field splitting of D/k(B) = -0.498 K, quartic longitudinal zero-field splitting of B4(omicron)/k(B) = 1.72 x 10(-5) K, and rhombic zero-field splitting of E/k(B) = 0.124 K. Complex 2-4H2O exhibits a frequency-dependent out-of-phase AC magnetic susceptibility signal, clearly indicating that this complex functions as a SMM. The AC susceptibility data for complex 2-4H2O were measured in the 0.05-4.0 K range and when fit to the Arrhenius law, gave an activation energy of DeltaE = 15.8 K for the reversal of magnetization. This DeltaE value is to be compared to the potential-energy barrier height of U/k(B) = absolute value DSz(2) = 40.3 K calculated for 2-4H2O.

Metoprolol and mephenytoin oxidation polymorphisms in Far Eastern Oriental subjects: Japanese versus mainland Chinese

We examined genetically determined oxidation polymorphisms of metoprolol and mephenytoin in 200 unrelated, healthy Japanese subjects and in 98 mainland Chinese subjects simultaneously. This examination was done according to the respective reported phenotyping criteria by use of the urinary metabolic ratio of metoprolol and of the percentage of excretion of 4-hydroxymephenytoin 8 hours after dose administration. The frequencies of occurrence of poor metabolizers (PMs) in the Japanese versus the Chinese subjects were 0.5% versus 0% for metoprolol and 22.5% versus 17.4% for mephenytoin, respectively. There were no statistically significant differences in these frequencies between the two Oriental populations. However, Chinese extensive metabolizers (EMs) showed a significantly lower excretion of alpha-hydroxymetoprolol (p less than 0.01) and 4-hydroxymephenytoin (p less than 0.001) than that of Japanese EMs, and the mode of the distribution histogram of the Chinese EMs for the two test probes was skewed compared with that of the Japanese EMs. The findings indicate that the two Far Eastern Oriental subject groups have a lower frequency of PM phenotype of debrisoquin/sparteine-type oxidation and a greater incidence of PM phenotype of mephenytoin oxidation compared with the respective frequencies reported from white subjects. However, the explanation for the observation that the metabolic capacities of the test drugs differed between the EMs of the two populations who had a similar ethnic origin and who resided in the same geographic area remains obscure.

Antibody formation: stimulation by polyadenylic and polycytidylic acids

Complexes of polyadenylic and polyuridylic acids, or of polycytidylic acid and methylated bovine serum albumin, enhance the early rate of increase in numbers of antibody-forming spleen cells in mice immunized with sheep red blood cells or other particulate antigens. Polyadenylic and polycytidylic acids, respectively, appear to be the source of the critical stimulators which, as demonstrated by others in bacteria, may act by influencing nucleotide kinase activity. The stimulated antibody response, but not the normal response, is antagonized by kinetin riboside and by an adenosine derivative occurring in sRNA.

Very-long-period seismic signals and caldera formation at Miyake Island, Japan

Over a period of roughly 40 days, starting on 8 July 2000, a caldera structure 1.7 kilometers in diameter developed by means of gradual depression and expansion of the summit crater at Miyake Island, Japan. At the same time, very-long-period (VLP) seismic signals were observed once or twice a day. Source mechanism analyses of the VLP signals show that the moment tensor solutions are smooth step functions over a time scale of 50 seconds, with dominant volumetric change components. We developed a model to explain the caldera and the VLP signals, in which a vertical piston of solid materials in the conduit is intermittently sucked into the magma chamber by lateral magma outflow. This model offers potential for making quantitative estimations of the characteristic physical properties of magma systems.

Homozygous mutations in ARIX(PHOX2A) result in congenital fibrosis of the extraocular muscles type 2

Isolated strabismus affects 1-5% of the general population. Most forms of strabismus are multifactorial in origin; although there is probably an inherited component, the genetics of these disorders remain unclear. The congenital fibrosis syndromes (CFS) represent a subset of monogenic isolated strabismic disorders that are characterized by restrictive ophthalmoplegia, and include congenital fibrosis of the extraocular muscles (CFEOM) and Duane syndrome (DURS). Neuropathologic studies indicate that these disorders may result from the maldevelopment of the oculomotor (nIII), trochlear (nIV) and abducens (nVI) cranial nerve nuclei. To date, five CFS loci have been mapped (FEOM1, FEOM2, FEOM3, DURS1 and DURS2), but no genes have been identified. Here, we report three mutations in ARIX (also known as PHOX2A) in four CFEOM2 pedigrees. ARIX encodes a homeodomain transcription factor protein previously shown to be required for nIII/nIV development in mouse and zebrafish. Two of the mutations are predicted to disrupt splicing, whereas the third alters an amino acid within the conserved brachyury-like domain. These findings confirm the hypothesis that CFEOM2 results from the abnormal development of nIII/nIV (ref. 7) and emphasize a critical role for ARIX in the development of these midbrain motor nuclei.

Cholesterol-lowering effects of maitake (Grifola frondosa) fiber, shiitake (Lentinus edodes) fiber, and enokitake (Flammulina velutipes) fiber in rats

The effects of mushroom fibers on serum cholesterol and hepatic low-density lipoprotein (LDL) receptor mRNA in rats were investigated. Rats were fed a cholesterol-free diet with 50 g/kg cellulose powder (CP), 50 g/kg maitake (Grifola frondosa) fiber (MAF), 50 g/kg shiitake (Lentinus edodes) fiber (SF), or 50 g/kg enokitake (Flammulina velutipes) fiber (EF) for 4 weeks. There were no significant differences in the body weight, food intake, liver weight, cecum weight, and cecum pH among the groups. Cecal acetic acid, butyric acid, and total short-chain fatty acid (SCFA) concentrations in the SF and EF groups were significantly higher than those in the other groups. The serum total cholesterol concentration in the CP group was significantly higher than that in the MAF and EF groups. The very LDL (VLDL) + intermediate-density lipoprotein (IDL) + LDL-cholesterol concentration in the CP group was significantly higher than that in the MAF, SF, and EF groups, whereas the high-density lipoprotein (HDL)-cholesterol concentration in the EF group was significantly lower than that in the other groups at the end of the 4-week feeding period. The hepatic LDL receptor mRNA level in the EF group was significantly higher than that in the CP group. The fecal cholesterol excretion in the MAF, SF, and EF groups was significantly higher than that in the CP group. The results of this study demonstrate that MAF and EF lowered the serum total cholesterol level by enhancement of fecal cholesterol excretion, and in particular, by enhancement of hepatic LDL receptor mRNA in EF group.

Electrolyzed-reduced water scavenges active oxygen species and protects DNA from oxidative damage

Active oxygen species or free radicals are considered to cause extensive oxidative damage to biological macromolecules, which brings about a variety of diseases as well as aging. The ideal scavenger for active oxygen should be 'active hydrogen'. 'Active hydrogen' can be produced in reduced water near the cathode during electrolysis of water. Reduced water exhibits high pH, low dissolved oxygen (DO), extremely high dissolved molecular hydrogen (DH), and extremely negative redox potential (RP) values. Strongly electrolyzed-reduced water, as well as ascorbic acid, (+)-catechin and tannic acid, completely scavenged O.-2 produced by the hypoxanthine-xanthine oxidase (HX-XOD) system in sodium phosphate buffer (pH 7.0). The superoxide dismutase (SOD)-like activity of reduced water is stable at 4 degrees C for over a month and was not lost even after neutralization, repeated freezing and melting, deflation with sonication, vigorous mixing, boiling, repeated filtration, or closed autoclaving, but was lost by opened autoclaving or by closed autoclaving in the presence of tungsten trioxide which efficiently adsorbs active atomic hydrogen. Water bubbled with hydrogen gas exhibited low DO, extremely high DH and extremely low RP values, as does reduced water, but it has no SOD-like activity. These results suggest that the SOD-like activity of reduced water is not due to the dissolved molecular hydrogen but due to the dissolved atomic hydrogen (active hydrogen). Although SOD accumulated H2O2 when added to the HX-XOD system, reduced water decreased the amount of H2O2 produced by XOD. Reduced water, as well as catalase and ascorbic acid, could directly scavenge H2O2. Reduce water suppresses single-strand breakage of DNA b active oxygen species produced by the Cu(II)-catalyzed oxidation of ascorbic acid in a dose-dependent manner, suggesting that reduced water can scavenge not only O2.- and H2O2, but also 1O2 and .OH.

Development of novel chitosan derivatives as micellar carriers of taxol

PURPOSE

To develop an intravenous injectable carrier composed of chitosan derivatives for taxol.

METHODS

A chitosan with lauryl groups attached to amino groups to provide the hydrophobic moieties and, carboxymethyl groups attached to hydroxy groups to provide the hydrophilic moieties (N-lauryl-carboxymethyl-chitosan = LCC), was newly synthesized. The solubility of taxol in LCC micelles in aqueous solution was examined. The hemolysis test of LCC and the growth inhibition experiment of taxol-loading micelle using KB cells were also performed as in vitro assay.

RESULTS

It was found that LCC solubilized taxol by forming micelles with particle sizes less than 100nm. This particle size was considered effective for passive targeting for tumors. The concentration of taxol in the micellar solution was very high, with a maximum of 2.37mg/mL. This maximum was 1000 times above that in a saturated solution of taxol at pH 7.4. Hemolysis testing as an in vitro assay indicated that LCC was safer than Polysorbate 80 (TO-10M) as intravenous surfactant in terms of induction of membrane damage. As judged by cytostatic activity against KB cells, taxol retained activity even when included in LCC micelles. LCC-entrapped taxol was more effective in cytostatic activity than free taxol in low concentrations.

CONCLUSIONS

The results of solubilization capacity examination, hemolysis testing, and cytostatic activity suggest that LCC may be useful as a carrier of taxol.

Thermodynamics-structure relationship of single mismatches in RNA/DNA duplexes

Thermodynamics of 66 RNA/DNA duplexes containing single mismatches were measured by UV melting methods. Stability enhancements for rG. dT mismatches were the largest of all mismatches examined here, while rU.dG mismatches were not as stable. The methyl group on C5 of thymine enhanced the stability by 0.12 approximately 0.53 kcal mol(-)(1) depending on the identity of adjacent Watson-Crick base pairs, whereas the 2'-hydroxyl group in ribouridine stabilized the duplex by approximately 0.6 kcal mol(-)(1) regardless of the adjacent base pairs. Stabilities induced by the methyl group in thymine, the 2'-hydroxyl group of ribouridine, and an nucleotide exchange at rG.dT and rU.dG mismatches were found to be independent of each other. The order for the mismatch stabilities is rG.dT >> rU. dG approximately rG.dG > rA.dG approximately rG.dA approximately rA. dC > rA.dA approximately rU.dT approximately rU.dC > rC.dA approximately rC.dT, although the identity of the adjacent base pairs slightly altered the order. The pH dependence stability and structural changes were suggested for the rA.dG but not for rG.dA mismatches. Comparisons of trinucleotide stabilities for G.T and G.U pairs in RNA, DNA, and RNA/DNA duplexes indicate that stable RNA/DNA mismatches exhibit a stability similar to RNA mismatches while unstable RNA/DNA mismatches show a stability similar to that of DNA mismatches. These results would be useful for the design of antisense oligonucleotides.

Anti-HIV-1 activity of herbs in Labiatae

The anti-HIV-1 activity of aromatic herbs in Labiatae was evaluated in vitro. Forty five extract from among 51 samples obtained from 46 herb species showed significant inhibitory effects against HIV-1 induced cytopathogenicity in MT-4 cells. In particular, the aqueous extracts of Melissa officinalis, a family of Mentha x piperita "grapefruit mint," Mentha x piperita var. crispa, Ocimum basilicum cv "cinnamon," Perilla frutescens var. crispa f. viridis, Prunella vulgaris subsp. asiatica and Satureja montana showed potent anti-HIV-1 activity (with an ED of 16 microg/ml). The active components in the extract samples were found to be water-soluble polar substances, not nonpolar compounds such as essential oils. In addition, these aqueous extracts inhibited giant cell formation in co-culture of Molt-4 cells with and without HIV-1 infection and showed inhibitory activity against HIV-1 reverse transcriptase.

CD4(+) Valpha14 natural killer T cells are essential for acceptance of rat islet xenografts in mice

Pancreatic islet transplantation represents a potential treatment for insulin-dependent diabetes mellitus. However, the precise cellular and molecular mechanisms of the immune reactions against allogeneic and xenogeneic transplanted islets remain unclear. Here, we demonstrate that CD4(+) Valpha14 natural killer T (NKT) cells, a recently identified lymphoid cell lineage, are required for the acceptance of intrahepatic rat islet xenografts. An anti-CD4 mAb, administrated after transplantation, allowed islet xenografts to be accepted by C57BL/6 mice, with no need for immunosuppressive drugs. The dose of anti-CD4 mAb was critical, and the beneficial effect appeared to be associated with the reappearance of CD4(+) NKT cells at around 14 days after transplantation. Interestingly, rat islet xenografts were rejected, despite the anti-CD4 mAb treatment, in Valpha14 NKT cell-deficient mice, which exhibit the normal complement of conventional lymphoid cells; adoptive transfer of Valpha14 NKT cells into Valpha14 NKT cell-deficient mice restored the acceptance of rat islet xenografts. In addition, rat islet xenografts were accepted by Valpha14 NKT mice having only Valpha14 NKT cells and no other lymphoid cells. These results indicate that Valpha14 NKT cells play a crucial role in the acceptance of rat islet xenografts in mice treated with anti-CD4 antibody, probably by serving as immunosuppressive regulatory cells.

A possible mechanism of the generation of singlet molecular oxygen in nadph-dependent microsomal lipid peroxidation

A simplified system, consisting of NADPH, Fe3+-ADP, EDTA, liposomes, NADPH-cytochrome c reductase and Tris - HCl buffer (pH 6.8), has been employed in studies of the generation of singlet oxygen in NADPH-dependent microsomal lipid peroxidation. The light emitted by the system involves 1deltag type molecular oxygen identifiable by its characteristic emission spectrum and its behavior with beta-carotene. The generation of another excited species (a compound in the triplet state) could be demonstrated in this system by changes of light intensity and emission spectra which arise from photosensitizer (9,10-dibromoanthracene sulfonate, eosin, Rose-Bengal)-mediated energy transfers. Chemiluminescence in the visible region was markedly quenched by various radical trappers and by an inhibitor of NADPH-cytochrome c reductase, but not by superoxide dismutase. During the early stage of lipid peroxidation, the intensity of chemiluminescence was proportional to the square of the concentration of lipid peroxide. These characteristics suggest that singlet oxygen and a compound in the triplet state (probably a carbonyl compound) are generated by a self-reaction of lipid peroxy radicals.

Preparation and evaluation of w/o/w type emulsions containing vancomycin

The objective of this contribution is to summarize the preparation and application of water-in-oil-in-water type multiple emulsions (w/o/w emulsions) entrapping vancomycin (VCM). Formulations of the emulsions (the composition of an oily phase or the type and concentrations of surfactants) and emulsification methods (a stirring method and a membrane method) or conditions (rotation rates, pore sizes of membrane or operation pressures) were evaluated in order to prepare stable w/o/w emulsions. The pharmaceutical properties of the w/o/w emulsions - particle sizes, viscosity, phase separation and drug entrapment efficiency were measured and evaluated. We prepared stable w/o/w emulsions with a particle size of about 3 micrometer and an entrapment efficiency of VCM of about 70%. When this emulsion was administered intravenously to rats, plasma concentrations of VCM were prolonged compared to the VCM solution alone. The results of this study show the potential of the w/o/w emulsions for several clinical applications as one of the drug delivery systems.

Oral administration of (-)catechin protects against ischemia-reperfusion-induced neuronal death in the gerbil

The effect of ad libitum oral-administration of (-)catechin solution on ischemia-reperfusion-induced cell death of hippocampal CA1 in the gerbil was histologically examined. When (-)catechin solution instead of drinking water was orally administered ad libitum for 2 weeks, dose-dependent protection against neuronal death following by transient ischemia and reperfusion was observed. To evaluate the involvement of reduction of reactive-oxygen-species (ROIs) by the antioxidant activity of (-)catechin in this protection, the superoxide scavenging activity of the brain in catechin-treated gerbils was measured by ESR and spin-trapping using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). The superoxide scavenging activities of the brains obtained from catechin-treated gerbils were significantly higher than those of catechin-untreated animals. From these results, it was suggested that orally administered (-)catechin was absorbed, passed through the blood-brain barrier and that delayed neuronal death of hippocampal CA1 after ischemia-reperfusion was prevented due to its antioxidant activities.

Mechanism of O2- generation in reduction and oxidation cycle of ubiquinones in a model of mitochondrial electron transport systems

O2- generation in mitochondrial electron transport systems, especially the NADPH-coenzyme Q10 oxidoreductase system, was examined using a model system, NADPH-coenzyme Q1-NADPH-dependent cytochrome P-450 reductase. One electron reduction of coenzyme Q1 produces coenzyme Q1-. and O2- during enzyme-catalyzed reduction and O2+ coenzyme Q1-. are in equilibrium with O2- + coenzyme Q1 in the presence of enough O2. The coenzyme Q1-. produced can be completely eliminated by superoxide dismutase, identical to bound coenzyme Q10 radical produced in a succinate/fumarate couple-KCN-submitochondrial system in the presence of O2. Superoxide dismutase promotes electron transfer from reduced enzyme to coenzyme Q1 by the rapid dismutation of O2- generated, thereby preventing the reduction of coenzyme Q1 by O2-. The enzymatic reduction of coenzyme Q1 to coenzyme Q1H2 via coenzyme Q1-. is smoothly achieved under anaerobic conditions. The rate of coenzyme Q1H2 autoxidation is extremely slow, i.e., second-order constant for [O2][coenzyme Q1H2] = 1.5 M-1.s-1 at 258 microM O2, pH 7.5 and 25 degrees C.