Effects of vitamin supplementation on microcirculatory disturbance in hemodialysis patients without peripheral arterial disease.

AIMS: Dysfunctional endothelium caused by oxidative stress is thought to play a role in pathogenesis of a variety of conditions including atherosclerosis. We investigated whether a microcirculatory disturbance in hemodialysis (HD) patients was associated with increased oxidative stress and endothelial injury. PATIENTS AND METHODS: Transcutaneous oxygen tension (TcPO2) on the dorsum of the foot at rest was measured as a marker of microcirculation in 33 patients undergoing HD without clinical manifestations of peripheral arterial disease and 20 healthy controls. Furthermore, in order to examine whether TcPO2 was affected by antioxidants, oral supplementation with a combination of vitamin C (200 mg daily) and vitamin E (600 mg daily) was administered for 6 months to 8 patients with microcirculatory disturbance (TcPO2 values of 50 mmHg or less). Serum biochemical parameters including vitamins were also measured. RESULTS: Mean TcPO2 value was significantly lower in HD patients than in control subjects (47.9 +/- 13.5 mmHg versus 62.4 +/- 11.9 mmHg, p < 0.001). After vitamin supplementation, TcPO2 values remarkably increased (40.6 +/- 10.0 mmHg versus 57.4 +/- 6.5 mmHg, p < 0.005). Serum vitamin C and vitamin E levels increased significantly as well, while serum levels of thrombomodulin, a marker of endothelial injury, and thiobarbituric acid reactants, a marker of lipid peroxidation, were significantly decreased in comparison with those before supplementation. CONCLUSIONS: Our results suggest that the microcirculatory disturbance in HD patients seems to be associated with endothelial damage caused by oxidative stress. Combined supplementation with vitamin C and vitamin E may be of clinical benefit in improving the cutaneous microcirculation by reducing oxidative stress.

Celogentins A-C, new antimitotic bicyclic peptides from the seeds of Celosia argentea.

Three new bicyclic peptides, celogentins A (1), B (2), and C (3), have been isolated together with a known-related peptide, moroidin (4), from the seeds of Celosia argentea, and their structures including absolute stereochemistry were determined by using extensive NMR methods and chemical means. Celogentins A (1), B (2), and C (3) inhibited the polymerization of tubulin, and celogentin C (3) was four times more potent than moroidin (4) in the inhibitory activity. Structure-activity relationship study using moroidin derivatives 5-7 and analogue 8 as well as celogentins A-C (1-3) and moroidin (4) indicates that the bicyclic ring system including unusual non-peptide connections among beta(s)-Leu, Trp, and His residues characteristic of celogentins and moroidin, with ring size and conformations suitable for interaction with tubulin would be important for their biological activity.

Benzalacetone synthase. A novel polyketide synthase that plays a crucial role in the biosynthesis of phenylbutanones in Rheum palmatum.

Benzalacetone synthase (BSA) is a novel plant-specific polyketide synthase that catalyzes a one step decarboxylative condensation of 4-coumaroyl-CoA with malonyl-CoA to produce the C6-C4 skeleton of phenylbutanoids in higher plants. A cDNA encoding BAS was for the first time cloned and sequenced from rhubarb (Rheum palmatum), a medicinal plant rich in phenylbutanoids including pharmaceutically important phenylbutanone glucoside, lindleyin. The cDNA encoded a 42-kDa protein that shares 60-75% amino-acid sequence identity with other members of the CHS-superfamily enzymes. Interestingly, R. palmatum BAS lacks the active-site Phe215 residue (numbering in CHS) which has been proposed to help orient substrates and intermediates during the sequential condensation of 4-coumaroyl-CoA with malonyl-CoA in CHS. On the other hand, the catalytic cysteine-histidine dyad (Cys164-His303) in CHS is well conserved in BAS. A recombinant enzyme expressed in Escherichia coli efficiently afforded benzalacetone as a single product from 4-coumaroyl-CoA and malonyl-CoA. Further, in contrast with CHS that showed broad substrate specificity toward aliphatic CoA esters, BAS did not accept hexanoyl-CoA, isobutyryl-CoA, isovaleryl-CoA, and acetyl-CoA as a substrate. Finally, besides the phenylbutanones in rhubarb, BAS has been proposed to play a crucial role for the construction of the C6-C4 moiety of a variety of natural products such as medicinally important gingerols in ginger plant.

Diet-induced hyperhomocysteinemia exacerbates neointima formation in rat carotid arteries after balloon injury.

BACKGROUND: Increasing evidence indicates that elevated plasma homocysteine levels are associated with an increased risk of atherosclerosis and endothelial dysfunction, although little specific information on the mechanisms responsible for the atherogenic effects of homocysteine or on the in vivo contribution made by hyperhomocysteinemia to atherosclerosis is currently available. Because homocysteine is known to exert a direct inhibitory effect on endothelial cell growth in vitro, we hypothesized that this effect contributes to the progression of atherosclerotic lesions initiated by endothelial damage caused by mechanical injury. METHODS AND RESULTS: We prepared diet-induced hyperhomocysteinemic rats in which neointima formation after balloon injury to the common carotid artery was assessed. Moderate hyperhomocysteinemia (plasma homocysteine levels 3- to 4-fold higher than control) significantly exacerbated neointima formation. Oral administration of folate, which had a homocysteine-lowering effect, diminished neointima formation induced by moderate hyperhomocysteinemia. Furthermore, the attenuation of reendothelialization was shown in diet-induced hyperhomocysteinemic rats with Evans blue staining. CONCLUSIONS: Diet-induced hyperhomocysteinemia, even mild to moderate, exacerbates neointima formation after denuding injury, making hyperhomocysteinemia a likely risk factor for postangioplasty restenosis. It may be mediated through an inhibitory effect of homocysteine on reendothelialization. Homocysteine lowering with folate supplementation can effectively ameliorate the detrimental effects of moderate hyperhomocysteinemia. Clinical trials would seem to be warranted.

Effects of L-carnitine supplementation on cardiac morbidity in hemodialyzed patients.

Cardiac diseases are well known among patients on maintenance hemodialysis (HD), and carnitine deficiency may be an important factor in cardiac morbidity. We studied the effects of low-dose L-carnitine treatment (500 mg/day) on chest symptoms (dyspnea on exertion, chest pain, palpitation), cardiac function, and left ventricular (LV) mass in 9 HD patients with reduced ejection fraction (EF). After 6 months of L-carnitine treatment, most patients had at least some improvement in chest symptoms, while LVEF was increased and LV mass was decreased. Carnitine fractions increased and reached plateaus at 2-3 times the baseline levels. These results suggest that prolonged low-dose L-carnitine treatment can improve the cardiac morbidity by restoring decreased carnitine tissue levels and impaired oxidation of FFA.

Antimitotic activity of moroidin, a bicyclic peptide from the seeds of Celosia argentea.

A unique bicyclic peptide, moroidin (1), from the seeds of Celosia argentea (Amaranthaceae) strongly inhibited the polymerization of tubulin. The stereostructure of moroidin (1) was reinvestigated by spectroscopic data, chemical degradation, and molecular dynamics simulation.

Synthesis of the fatty sterol bound protein for a new sterol antibody.

For the purpose of applying the particular antibodies as a new diagnostic procedure for atherosclerosis and related diseases, we successfully achieved the synthesis of the fatty sterol with a linker, then linked the target protein to this sterol. Synthesis was started from pregnenolone and achieved by the Grignard reaction with pentenyl magnesium bromide, regioselective photoaddition of thiolacetic acid toward the 25-double bond, esterification of 3-OH with linoleic anhydride, in situ conjunction of the cross-linker (MBS) to the thiol group after selective deprotection from its acetyl ester, and finally by the reaction with protein such as KLH or albumin through this linker.

[Antitumor compounds isolated from higher plants].

A lot of anticancer agents have been isolated from natural sources, especially from microorganisms and plants. However, there is no special type of compounds for cancer therapy. Various types of substances are effective for various types of cancers and tumors: for instance, alkaloids, lignans, terpenes and steroids, etc. In this report, the authors will describe especially about higher plants.

Effects of L-carnitine supplementation on muscular symptoms in hemodialyzed patients.

Various muscle symptoms are well recognized among patients on maintenance hemodialysis. Carnitine deficiency may be an important factor of dialysis-associated muscle symptoms, whereas high-dose L-carnitine supplementation may result in unphysiologically high plasma levels of carnitine and carnitine esters. We studied the effect of low-dose L-carnitine treatment (500 mg/d) on muscle symptoms, plasma carnitine fractions, and lipid profiles in 30 periodically dialyzed patients with muscular weakness, fatigue, or cramps/aches. After 12 weeks of L-carnitine treatment, about two-thirds of patients had at least some improvement in muscular symptoms, whereas carnitine fractions were normal or slightly above normal ranges, but lipid profiles showed no demonstrable changes. This study also showed the correlation between plasma-free carnitine deficiency and months on dialysis. These results suggest that prolonged low-dose L-carnitine treatment can improve dialysis-associated muscle symptoms by restoring carnitine tissue levels and washing out acyl moieties.

Triterpenoid saponin from Vaccaria segetalis.

A new triterpenoid saponin, vaccaroid B, has been isolated from the seeds of Vaccaria segetalis and its structure was elucidated to be 3beta-hydroxyolean-12-en-23, 28-dioic acid-28-O-beta-D-glucopyranosyl-(1-->3)- beta-D-glucopyranosyl-(1-->6)-[6- O-(3-hydroxy-3-methylglutaryl)-beta-D-glucopyranosyl-(1-->2)]- beta-D-glucopyranoside by spectroscopic methods.

Four new taxoids from Taxus cuspidata var. nana.

Four new taxoids ( 1- 4), showing cytotoxic activity, have been isolated from the stems of Taxus cuspidata Sieb. et. Zucc. var. nana Rehder. Their structures were elucidated by extensive 2D NMR methods including (1)H- (1)H COSY, TOCSY, HMBC, HMQC, and phase sensitive ROESY spectra.

High performance liquid chromatography in phytochemical analysis of Eurycoma longifolia.

An analytical method using HPLC with UV detection was developed to investigate the quassinoid content of Eurycoma longifolia Jack (Simaroubaceae) collected from various sources. Eurycomanone (1), longilactone (2), 14,15beta-dihydroxyklaineanone (3), 15beta-acetyl-14-hydroxyklaineanone (4), 6alpha-hydroxyeurycomalactone (5), and eurycomalactone (7) were isolated as reference standards and together with the synthesized 1beta,12alpha,15beta-triacetyleurycomanone (6, internal standard), were identified by NMR, MS, UV and IR spectroscopies. Their coefficient of variation values for 0.50-35 microg ml(-1) concentrations of quassinoids and their retention times measured within- and between-day were small. The recoveries of the spiked quassinoids in E. longifolia samples and their detection limits at 8.5 times signal to noise ratio were 99.75-109.13% and 0.01 microg ml(-1), respectively. From the root samples analysed, 1 had the highest concentration, being about 16.8-39.6 fold higher than the other quassinoids 2, 3, 5, 7 but 145.3 fold higher than 4 which showed the lowest concentration.

Cyclic octapeptides from Stellaria dichotoma var. lanceolata.

Two new cyclic octapeptides, dichotomin H, cyclo(-Ala-Pro-Thr-Phe-Tyr-P ro-Leu-Ile-), and dichotomin I, cyclo(-Val-Pro-Thr-Phe-Tyr-Pro-Leu-Ile-) have been isolated from the roots of Stellaria dichotoma L. var lanceolata Bge., and their structures were elucidated by extensive two-dimensional NMR methods and chemical degradation.

Taxuspinananes A and B, new taxoids from Taxus cuspidata var. nana.

New taxoids, taxuspinanane A (1), showing potent cytotoxic activity, and taxuspinanane B (2), have been isolated from the stems of Taxus cuspidata Sieb. et. Zucc. var. nana Rehder. Their structures were elucidated by extensive 2D NMR and MS spectroscopic analysis.

[31P magnetic resonance spectroscopy(MRS) study in basal ganglia of patients with Parkinson's disease].

We report 31P magnetic resonance spectroscopy(MRS) to study regional high energy phosphate and phospholipid metabolism in basal ganglia of patients with Parkinson's disease(PD) in comparison with normal controls. The ratio of phosphomonoester(PME)/phosphocreatine(PCr), phosphodiester(PDE)/PCr and total Adenosine triphosphate(ATP) tend to decrease and the ratio of PDE/PME tend to elevate compared with controls. Moreover these findings are correlated with the duration of illness. Our results suggest that neural elements in basal ganglia may be damaged in PD. In conclusion, 31P-MRS appears to be useful for the study of neural damage and degeneration in vivo.

Corticosteroid synthesis in the central nervous system.

The possibility that adrenocorticosteroids might be synthesized in the central nervous system was assessed by RT-PCR using primers for the CYP11B1 gene which codes for 11 beta-hydroxylase, the enzyme responsible for corticosterone and cortisol formation in the zona fasciculata, incubation of minces of several areas of the brain with 3H-DOC and measuring steroid metabolites, and determining the effect of the intracerebroventricular infusion of the 11 beta-hydroxylase mechanism-based inhibitor 19-ethynyldeoxycorticosterone upon the salt-induced increase in blood pressure in SS/jr rats. Significant, though small relative to the adrenal, amounts of mRNA for 11 beta-hydroxylase was found in the aorta, cerebrum, cerebellum, hippocampus, hypothalamus and amygdala, but not in the heart. Brain minces converted 3H-DOC to corticosterone and 11-dehydrocorticosterone to a greater degree than to 18-OH-DOC. The effect of 19-ethynyldeoxycorticosterone was dose dependent, with the lower doses preventing salt-induced hypertension and the higher doses having no effect or increasing the blood pressure.

Modulation of picryl chloride-induced contact hypersensitivity reaction in mice by nitric oxide.

We have studied the possible involvement of nitric oxide (NO) in the contact hypersensitivity reaction. A biphasic response of ear swelling was observed at 2 h (early phase) and 24 h (late phase) after application of the antigen to picryl chloride (PC1)-sensitized CBA/J mice. Intravenous injection of NO synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), at the time of PC1 challenge, inhibited in a concentration-dependent fashion the antigen-induced contact hypersensitivity reaction. Low-dose (1 mg/kg) L-NAME inhibited the early-phase reaction but not the late-phase reaction. High-dose (250 mg/kg) L-NAME inhibited both early- and late-phase reactions. D-NAME (enantiomer of L-NAME) did not inhibit the antigen-induced ear swelling. High-dose (250 mg/kg) L-arginine increased both early and late phase reactions. D-Arginine (enantiomer of L-arginine) did no increase the antigen-induced ear swelling. L-NAME injection, however, did not suppress phenol-induce irritant inflammation. Treatment of mice undergoing PC1-induced contact hypersensitivity reaction with L-NAME reduced the production of interleukin-2 and interferon-gamma by draining lymph node cells. Treatment with L-arginine, on the other hand increased the production of interleukin-2 and interferon-gamma. These results suggest that NO plays a modulating role in contact hypersensitivity reaction.

Macrocarpals H, I, and J from the Leaves of Eucalyptus globulus.

A 50% EtOH extract of Eucalyptus globulus leaves yielded eight phloroglucinol--sesquiterpene-coupled constituents, including three novel compounds named macrocarpals, H, I, and J. Some of these compounds possessed antibacterial activity against oral pathogenic microorganisms with MIC values ranging from 0.20 micrograms/mL to 6.25 micrograms/mL. Inhibition of glucosyltransferase activity by these compounds was also noted.

11 beta-Hydroxysteroid dehydrogenase type 2 complementary deoxyribonucleic acid stably transfected into Chinese hamster ovary cells: specific inhibition by 11 alpha-hydroxyprogesterone.

The 11 beta-hydroxysteroid dehydrogenase type 2 (11 beta HSD-2) enzyme is thought to confer aldosterone specificity upon mineralocorticoid target tissues by protecting the mineralocorticoid receptor from binding by the more abundant glucocorticoids, corticosterone and cortisol. We have developed a Chinese hamster ovary cell line stably transfected with a plasmid containing the rat 11 beta HSD-2 complementary DNA. This cell line has expressed the enzyme consistently for many generations. The 11 beta HSD-2 was located primarily in the microsomes, but significant amounts also existed in the nuclei and mitochondria. The enzymatic reaction was unidirectional, oxidative, and inhibited by the product, 11-dehydrocorticosterone, with an IC50 of approximately 200 nM. The K(m) for corticosterone was 9.6 +/- 3.1 nM, and that for NAD+ was approximately 8 microM. The enzyme did not convert dexamethasone to 11-dehydrodexamethasone. Tunicamycin, an N-glycosylation inhibitor, had no effect on enzyme activity. 11 alpha-Hydroxyprogesterone (11 alpha OH-P) was an order of magnitude more potent a competitive inhibitor of the 11 beta HSD-2 than was glycyrrhetinic acid (GA) (approximate IC50 = 0.9 vs. 15 nM). 11 beta OH-P, progesterone, and GA were almost equipotent (IC50 = 10 and 6 nM, respectively), and 5 alpha-pregnandione and 5 beta-pregnandione were less potent (IC50 = 100 and 500 nM, respectively) inhibitors of the enzyme. When the inhibitory activities were examined with intact transfected cells, 11 alpha OH-P was more potent than GA (IC50 = 5 and 150 nM, respectively). 11 alpha OH-P was not metabolized by 11 beta HSD-2. We were unable to demonstrate the presence of 11 alpha OH-P in human urine. In conclusion, a cell line stably transfected with the rat 11 beta HSD-2 was created, and the enzyme kinetics, including inhibition, were characterized. 11 alpha OH-P was found to be a potent relatively specific inhibitor of the 11 beta HSD-2 enzyme. Its potential importance is that it is the most specific inhibitor of the 11 beta HSD-2 so far encountered and would aid in the study of the physiological importance of the isoenzyme.