Reversal of freshening trend of Antarctic Bottom Water in the Australian-Antarctic Basin during 2010s.

The Antarctic continental margin supplies the densest bottom water to the global abyss. From the late twentieth century, an acceleration in the long-term freshening of Antarctic Bottom Waters (AABW) has been detected in the Australian-Antarctic Basin. Our latest hydrographic observations reveal that, in the late 2010s, the freshening trend has reversed broadly over the continental slope. Near-bottom salinities in 2018-2019 were higher than during 2011-2015. Along 170° E, the salinity increase between 2011 and 2018 was greater than that observed in the west. The layer thickness of the densest AABW increased during the 2010s, suggesting that the Ross Sea Bottom Water intensification was a major source of the salinity increase. Freshwater content on the continental slope decreased at a rate of 58 ± 37 Gt/a in the near-bottom layer. The decadal change is very likely due to changes in Ross Sea shelf water attributable to a decrease in meltwater from West Antarctic ice shelves for the corresponding period.

The cross-sectional area changes in digital flexor tendons and suspensory ligament in foals by ultrasonographic examination.

REASONS FOR PERFORMING STUDY: Flexural deformities are common conditions of growing horses and are suggested to have a relationship with the contraction of musculotendinous units. However, limited studies have documented the changes in each tendon and ligament in the metacarpal region with age. OBJECTIVES: To investigate the changes in the cross-sectional area (CSA) of each tendon and ligament in the metacarpal region with age by ultrasonographic examination. STUDY DESIGN: Longitudinal study of foals from Day 1 to age 24 months. METHODS: The CSA of the superficial digital flexor tendon, deep digital flexor tendon, accessory ligament of the deep digital flexor tendon and suspensory ligament was measured by ultrasonographic examination at monthly intervals from Day 1 to age 24 months in 7 Thoroughbred foals. RESULTS: Changes in superficial digital flexor CSA in all regions were larger than those of other structures from 10 months to 15 months. The suspensory ligament CSA was significantly larger than those of other structures on Day 1 in both the region of suspensory origin (RSO) and region of suspensory body (RSBO). This condition continued until 2 months in the RSO and until 5 months in the RSBO. The changes in deep digital flexor CSA were larger than those of other structures from 2 to 5 months in both the RSO and RSBO. CONCLUSIONS: The rate of change in each structure varies with age. Thus, the functional adaptation with age that takes place may differ among structures because the primary function of each structure differs.

Empirical growth curve estimation considering multiple seasonal compensatory growths of body weights in Japanese Thoroughbred colts and fillies.

Thoroughbred horses are seasonal mating animals, and their foals are born yearly in spring seasons. In northern regions or countries, the foals generally show a typical seasonal compensatory growth pattern, where their growth rate declines in winter and increases in the next spring. In this study, a new empirical approach is proposed to adjust for this compensatory growth when growth curve equations are estimated, by using BW of Japanese Thoroughbred colts and fillies raised in Hidaka, Hokkaido. Based on the traditional Richards growth curve equation, new growth curve equations were developed and fit to the weight-age data. The foals generally experience 2 major winter seasons before their debut in horseracing. The new equations had sigmoid subfunctions that can empirically adjust the first and second year compensatory growths, combined with the Richards biological parameter responsible for the maturity of animals. The unknown parameters included in the equations were estimated by SAS NLMIXED procedure. The goodness-of-fit was examined by using several indices of goodness-of-fit (i.e., Akaike's information criterion, Bayesian information criterion, -2 log likelihood, and residual sum of squares) for the multiple applications of the subfunctions. The indices indicated the best fit of the new equations including both subfunctions for the first and second compensatory growths to the weight-age data. The shapes of the growth curves were improved during the periods of compensatory growth. The proposed method is one of the useful approaches for adjusting multiple seasonal compensatory growths in growth curve estimations of Thoroughbreds and for the management of young horses during the compensatory periods.

Three-dimensional ultrasound imaging of the equine fetus.

The objective was to assess the optimal procedure for real-time, three-dimensional (3D) ultrasound (US) imaging for assessing the equine fetus during the first half of gestation and the possibility of using 3D US imaging of the equine fetus in clinical applications. Seventeen pregnant mares were examined by 3D US between Days 35 and 180 of gestation. Abdominal and endo-vaginal real-time 3D transducers used in human medicine were used for transrectal and transvaginal examinations, respectively. Images were recorded by both 3D stationary and real-time movies. In a comparison of four methods, transrectal examination with a bulb-shaped abdominal 3D transducer enabled the equine fetus to be clearly visualized, and did not require sedation of the mare. Therefore, this approach was the most suitable procedure for examining equine fetuses during the first half of gestation. Each scan required only a few seconds and an entire examination took <10 min in total. The 3D volume image was easy to restore after the examination and could be rotated to any angle the examiner desired. Fetal surface structures, including the head, body, limbs, and genital tubercle, were observed as 3D images which enabled fetal development to be characterized. For early (Days 60-70), but not later (Days 90-150) periods, 3D ultrasonography was not able to evaluate fetal structure in detail as well as conventional 2D ultrasonography. In conclusion, 3D ultrasonography of the equine fetus was a valuable adjunct to 2D ultrasonography and a convenient modality for more detailed assessment of fetal structures.

The Phase III, double-blind, parallel-group controlled study of amlodipine 10 mg once daily in Japanese patients with essential hypertension who insufficiently responded to amlodipine 5 mg once daily.

The objective of this Phase III double-blind parallel-group controlled study was to examine the superiority of amlodipine 10 mg once daily (the amlodipine 10 mg group) to amlodipine 5 mg once daily (the amlodipine 5 mg group) in 305 Japanese outpatients with essential hypertension whose systolic blood pressure (SBP) had not reached the therapeutic target levels (<130-140/80-90 mm Hg) when treated with amlodipine 5 mg once daily. This study consisted of the 1-week prescreening, 8-week screening and 8-week double-blind periods. Changes in trough SBP from baseline at week 8 of the double-blind period (week 8) were -7.0 mm Hg and -13.7 mm Hg in the amlodipine 5 and 10 mg groups, respectively; a significant difference (P<0.001) was found between the two groups. Changes in trough diastolic blood pressure (DBP) from baseline at week 8 were -2.7 mm Hg and -6.8 mm Hg in the amlodipine 5 and 10 mg groups, respectively, with a significant difference (P<0.001) between the two groups. At week 8, responder rates were 28.5 and 44.0% in the amlodipine 5 mg and 10 mg groups, respectively, with a significant difference (P=0.002) between the two groups. The amlodipine 10 mg group showed no significant difference in the incidences of adverse events against the amlodipine 5 mg group. The incidence of mild peripheral oedema was 4% only in the amlodipine 10 mg group. In conclusion, amlodipine 10 mg once daily was found to be superior to amlodipine 5 mg once daily, safe, well tolerated and useful for the relevant subjects.

Effects of phenolic compounds on reactions involving various organic radicals.

Investigation of effects produced by 26 various phenol and diphenol derivatives, including industrial and natural antioxidants (ionol, bis-phenol 2246, alpha-tocopherol), on final product yields of radiation-induced free-radical processes involving peroxyl, alkyl, alpha-hydroxyalkyl and alpha,beta-dihydroxyalkyl radicals has been performed. Ionol and bis-phenol 2246 have been shown to be more effective than alpha-tocopherol or diphenol derivatives in suppressing hydrocarbon oxidation processes. At the same time, alpha-tocopherol and its water-soluble analogues, as well as diphenol-based substances, are more effective than phenol derivatives in regulating various homolytic processes involving carbon-centered radicals. This fact can be accounted for by taking into consideration the contribution to formation of the final product set and the respective yields made by semiquinone radicals and compounds with quinoid structure arising in the course of homolytic transformations in systems containing diphenol derivatives.

In vivo radioprotection by alpha-TMG: preliminary studies.

alpha-TMG is a novel water-soluble derivative of Vitamin E that has shown excellent antioxidant activity. The parent compound has demonstrated protection against radiation induced chromosomal damage in vivo. Hence, the preliminary experiments to determine the radioprotective activity of alpha-TMG were carried out in adult Swiss albino mice. Acute toxicity of the drug was studied taking 24h, 72 h and 30 day mortality after a single intraperitoneal injection of 500-2000 mg/kg body weight of the drug. The drug LD(50) for 24h and 72 h/30 day survival were found to be 1120 and 1000 mg/kg body weight, respectively. The optimum time of drug administration and drug dose-dependent effect on in vivo radiation protection of bone marrow chromosomes was studied in mice. Injection of 600 mg/kg of the drug 15 min before or within 5, 15 or 30min after 3Gy whole body gamma radiation resulted in a significant decrease in the aberrant metaphases percent at 24h post-irradiation; the maximum effect was seen when the drug was given immediately after irradiation. Injection of 200-800 mg/kg TMG within 5 min of irradiation with 3 Gy produced a significant dose-dependent reduction in the radiation induced percent aberrant metaphases and in the frequency of micronucleated erythrocytes at 24h after exposure, with a corresponding decrease in the different types of aberrations. The optimum dose for protection without drug toxicity was 600 mg/kg body weight. At this dose, TMG produced 70 and >60% reduction in the radiation induced percent aberrant metaphases and micronucleated erythrocytes, respectively. The high water solubility and effectiveness when administered post-irradiation favor TMG as a likely candidate for protection in case of accidental exposures.

Intraocular pressure-lowering efficacy of latanoprost in patients with normal-tension glaucoma or primary open-angle glaucoma.

We investigated the intraocular pressure (IOP)-lowering potential of latanoprost in patients with normal-tension glaucoma (NTG) or primary open-angle glaucoma (POAG). This prospective study included 59 NTG and 20 POAG patients treated with the following four dosing regimens of latanoprost: patients on no previous medication received latanoprost as initial therapy (Group 1, n=31), patients on beta-blocker therapy received latanoprost as adjunctive therapy (Group II, n=9), patients on unoprostone monotherapy were switched to latanoprost monotherapy (Group III, n=14), and patients previously on dual therapy with isopropyl unoprostone and beta-blocker were switched to a combined treatment of latanoprost and beta-blocker (Group IV, n=25). IOP significantly decreased 8 weeks after initiation of latanoprost therapy by 19.9% in Group I, 20.5% in Group II, 16.6% in Group III, and 12.2% in Group IV. In Groups I and II, there was a significant positive correlation between the magnitude of IOP reduction induced by latanoprost and the IOP level before latanoprost therapy. The IOP level before latanoprost therapy is a contributing factor in the IOP-lowering efficacy of latanoprost. Latanoprost is more effective in lowering IOP than isopropyl unoprostone.

Analysis of the addition products of alpha-tocopherol with phosphatidylcholine-peroxyl radicals by high-performance liquid chromatography with chemiluminescent detection.

A chemiluminescence-based high-performance liquid chromatographic method was developed for the analysis of the addition products of alpha-tocopherol with phosphatidylcholine-peroxyl radicals (TOO-PC). The TOO-PC eluted from a reversed-phase column was reacted with a chemiluminescent reagent consisting of a Cypridina luciferin analog and a lipid-soluble iron chelate in acidic methanol at 50 degrees C, and the generated chemiluminescence was monitored. The detection limit for TOO-PC by this method was about 1 pmol. This method was applied to the detection of TOO-PC in the peroxidized membranes prepared from rabbit erythrocyte ghosts. When the erythrocyte ghosts were peroxidized by the addition of a water-soluble free radical initiator, a peak corresponding to TOO-PC was detected on the chromatogram with chemiluminescent detection. The amount of TOO-PC in the erythrocyte membranes increased with the depletion of endogenous alpha-tocopherol. The results indicate that this method proved useful for the detection of the TOO-PC formed by the peroxyl-radical scavenging reactions of alpha-tocopherol in biological systems.

Protective effect of a novel vitamin E derivative on experimental traumatic brain edema in rats--preliminary study.

Oxygen free radicals have been proposed to be one of the major mechanisms of secondary brain damage in traumatic brain injury. Protective effect by vitamin E against oxidative damage has attracted much attention. Recent studies have demonstrated a novel vitamin E derivative, 2-(alpha-D-glucopyranosyl)methyl-2,5,7,8-tetramethylchroman-6-ol (TMG), has excellent water-solubility and antioxidant activity. The purpose of this study was to investigate protective effects of TMG on experimental traumatic brain edema (BE). Male Wistar rats were anaesthetized with chloral hydrate. Traumatic BE was produced by a cortical freezing lesion. Animals were separated into three groups: saline-treated rats (n = 4), TMG-treated (4 mg/kg) rats (n = 7) and TMG-treated (40 mg/kg) rats (n = 8). Saline or TMG was administered intravenously before lesion production. Animals were sacrificed at 6 hours after lesion production and the brain water content was determined by the dry-wet weight method. Half-life of TMG after intravenous administration of TMG was also investigated. The half life of TMG was approximately 5 minutes. TMG (40 mg/kg) significantly attenuated BE following cryogenic brain injury (p < 0.01). In conclusion, this preliminary study has demonstrated that a novel vitamin E derivative might be promising in the treatment of traumatic BE.

Helicobacter pylori water extract induces interleukin-8 production by gastric epithelial cells.

In Helicobacter pylori-associated gastric mucosal injury, interleukin (IL) -8, a potent leukocyte chemoattractant, is produced by epithelial cells infected by H. pylori and directs neutrophils to the gastric mucosa. According to previous studies, the IL-8 production requires direct contact between the bacteria and epithelial cells. The aims of the present study were to determine whether an H. pylori water extract (HPE) induces IL-8 production by gastric epithelial cells and to characterize IL-8-inducing substances in HPE. Extracts were prepared from a standard strain and from strains obtained from patients with gastric ulcers. After addition of HPE to MKN 45 cells, a gastric cancer cell line, IL-8 in supernatants and IL-8 mRNA were measured by immunoassay and reverse transcription-polymerase chain reaction, respectively. For characterization, active fractions obtained by gel filtration of standard-strain HPE were treated by heating or trypsinization. To study the signal pathway leading to IL-8 production, inhibitors for protein kinase A (PKA), protein kinase C (PKC), or protein tyrosine kinase (PTK) were incubated with MKN45 cells before HPE stimulation. HPE from the standard strain and one of these clinical strains induced IL-8 production. Lipopolysaccharide or cagA in the strains showed no correlation with IL-8 concentration. Standard-strain HPE induced IL-8 mRNA expression in MKN 45 cells. Gel filtration localized activity to a low-molecular-weight fraction of about 7 kDa, which was resistant to heat and trypsin digestion. PKC inhibitors significantly blocked HPE-induced IL-8 production by MKN 45 cells; however, the PKA inhibitor or PTK inhibitors showed a partial inhibitory effect. HPE contains a nonprotein substance of low molecular weight that is responsible for IL-8 induction in gastric epithelial cells. This induction is mainly dependent on the activation of PKC but partially also dependent on PKA or PTK.

A novel water-soluble vitamin E derivative protects against experimental colitis in rats.

This study was designed to investigate the effects of water-soluble vitamin E derivative, 2-(alpha-D-glucopyranosyl)methyl-2,5,7,8-tetramethylchroman-6-ol (TMG), on experimental colitis in rats. Colitis was induced in male Wistar rats weighing 200 grams using an enema of trinitrobenzene sulfonic acid (TNBS) dissolved in 50% ethanol; 1 ml of TMG dissolved in physiological saline (0.2 mg/ml, 2 mg/ml, 20 mg/ml) was injected intraperitoneally every day for 1 week after the enema. The damage score, wet weight of the colon, and increase in body weight were estimated 1 week after the enema of TNBS. Thiobarbituric acid-reactive substances (TBA-RS), an index of lipid peroxidation, and the level of alpha-tocopherol or TMG in the colonic mucosa were measured 1 week after the induction of colitis. As a result, increase in body weight was inhibited by the induction of colitis, although the inhibition was reduced in the group treated with TMG. The damage score, wet weight and TBA-RS were increased significantly in the colitis group; however, they were inhibited by the administration of TMG. The alpha-tocopherol level in the colonic mucosa was reduced by the induction of colitis, wheres TMG could not be detected in the colonic mucosa of rats treated with TMG. These results suggest that TMG is effective for the treatment of colitis in rats induced by TNBS.

Ytterbium-decreasing Streptomyces sp. and its naphthoquinone-pigment production in the presence of rare-earth elements.

We screened for oligotrophic microorganisms capable of decreasing the concentration of ytterbium (Yb), a representative of the heavy rare-earth elements, in a culture medium. From 476 strains of oligotrophic microorganisms (grown on 1/100 diluted nutrient agar) isolated from soil and river water samples, 5 strains capable of reducing the concentration of Yb in diluted nutrient broth containing 5 ppm Yb were selected. Among them, a strain capable of reducing the concentration of all rare-earth elements to a great extent was identified as Streptomyces sp. (strain YB-1). This strain produced redish-purple pigment(s) only in the presence of rare earths, but not in that of other metals. The pigment was extracted with ethyl acetate and purified by a series of column chromatography steps. From the results of structural analysis using ultraviolet or infrared absorption spectrometry and 13C-NMR, the pigment was determined to be a kind of naphthoquinone similar to nanaomycin produced by a Streptomyces sp. These results suggested that rare earths might affect the physiological activity of this strain.

In vivo and in vitro effects of AVP and V1a receptor antagonist on Cushing's syndrome due to ACTH-independent bilateral macronodular adrenocortical hyperplasia.

We examined the possibility that AVP and V1a receptors were involved in regulating cortisol production in a 49 year old man with ACTH-independent bilateral macronodular adrenocortical hyperplasia (AIMAH), and investigated the effects of a V1a receptor antagonist. An i.v. injection of a small dose (0.1 or 0.3 U) of AVP, insulin-induced hypoglycaemia, upright posture tests, and oral administration of a V1a receptor antagonist (OPC-21268; 300 mg), and its repeated administration at a dose of 600 mg/day for 8 days were performed. An in vitro study of dispersed cells obtained from resected AIMAH tissue was also conducted. Plasma ACTH, AVP and cortisol levels and 24-h urinary free cortisol excretion were measured in the in vivo studies and cortisol concentrations in incubation media in the in vitro study. Injection of small doses of AVP stimulated cortisol secretion without any elevation of plasma ACTH. Insulin-induced hypoglycaemia caused a rise in plasma AVP followed by an increase in plasma cortisol. Although plasma cortisol levels were not affected by single or repeated administrations of OPC-21268, 24-h urinary free cortisol excretion was significantly decreased by the repeated treatment. In the in vitro study, more cortisol was stimulated by AVP from adrenal cells of the AIMAH tissue than from those of a normal adrenal gland, and this secretion was completely suppressed by OPC-21268. These results suggested that hypersensitivity to AVP may have contributed to overproduction of cortisol in this case of ACTH-independent bilateral macronodular adrenocortical hyperplasia, and may have contributed to its pathogenesis.

Antioxidant activity of a novel vitamin E derivative, 2-(alpha-D glucopyranosyl)methyl-2,5,7,8-tetramethylchroman-6-ol.

A novel vitamin E derivative, 2-(alpha-D-glucopyranosyl)methyl-2,5,7,8-tetramethylchroman-6-ol (TMG), has excellent water-solubility (> 1 x 10[3] mg/ml). The antioxidant activity of TMG was investigated. Kinetic studies of the inhibition of radical-chain reaction of methyl linoleate in solution demonstrated that the peroxyl radical-scavenging activity was not changed by the replacement of phytiyl side chain of vitamin E to glucosyl group. TMG acted as an effective inhibitor on lipid peroxidation of egg yolk phosphatidylcholine (PC)-liposomal suspension induced by a water-soluble and a lipid-soluble radical generator, 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) and 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN). Its effectiveness was higher than that of ascorbic acid (AsA) when liposomal suspension was exposed to a lipid-soluble radical generator, AMVN. TMG also showed an excellent antioxidant activity on cupric ion-induced lipid peroxidation of PC-liposomal suspension, and suppressed the oxidation of rat brain homogenate which contained trace level of iron ion. On the other hand, AsA acted as a prooxidant on both the cupric ion-induced liposomal peroxidation and the oxidation of rat brain homogenate. When human plasma was exposed to either AAPH or AMVN, the accumulation of cholesteryl ester hydroperoxides was retarded by the addition of TMG.

Effect of glucocorticoid receptor antagonist RU 38486 on acute glucocorticoid-induced insulin resistance in rat adipocytes.

We examined the mechanism of acute glucocorticoid-induced insulin resistance in rat adipocytes using the glucocorticoid receptor antagonist RU 38486. Pretreatment with dexamethasone (DEX) and prednisolone for 60 minutes resulted in 50% inhibition of insulin-induced [3H]2-deoxyglucose (DOG) uptake at 10(-8) and 10(-7) mol/L, respectively, in rat adipocytes and 20% and 25% inhibition of insulin-induced [3H]2-DOG uptake, respectively, in soleus muscles. Our previous experiments indicated that DEX and prednisolone alone stimulate protein kinase C (PKC) in rat adipocytes. Accordingly, we examined [3H]DEX binding to PKC from MonoQ column-purified rat brain cytosol. Specific [3H]DEX binding to MonoQ column-purified PKC was observed (kd, 56.8 nmol/L; Bmax, 725 fmol/mg protein). Thus, insulin-induced PKC translocation from the cytosol to the membrane was suppressed by pretreatment with 10(-7) mol/L DEX and 10(-6) mol/L prednisolone for 80 minutes. During treatment with RU 38486 for 60 minutes, there was no change in the glucocorticoid-induced inhibitory effect on insulin-induced [3H]2-DOG uptake and PKC translocation from the cytosol to the membrane. Moreover, pretreatment with RU 38486 for 120 minutes slightly prevented the DEX-mediated inhibition of insulin-induced glucose uptake. These results suggest that acute glucocorticoid-induced insulin resistance may be mainly mediated through the other non-glucocorticoid receptor pathway.

Synthesis of a novel vitamin E derivative, 2-(alpha-D-glucopyranosyl) methyl-2,5,7,8-tetramethylchroman-6-ol, by alpha-glucosidase-catalyzed transglycosylation.

A novel derivative of vitamin E, vitamin E glucoside, was synthesized from 2-hydroxymethyl-2,5,7,8-tetramethylchroman-6-ol and maltose in a solution containing DMSO by transglycosylation with alpha-glucosidase from Saccharomyces species. The glycosylated product was identified as 2-(alpha-D-glucopyranosyl)methyl-2,5,7,8-tetramethylchroman-6-ol (TMG) by mass spectrometry and nuclear magnetic resonance spectroscopy. The optimal pH of transglycosylation was 5.5, and the yield of TMG increased as the concentration of maltose increased. TMG has high solubility in water (> 1 x 10(3) mg/mL). The 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity of TMG was found to be nearly the same as those of alpha-tocopherol, Trolox (2-carboxy-2,5,7,8-tetramethylchroman-6-ol), and ascorbic acid.