Hiroshi Kuzuya

Determination of aloenin, barbaloin and isobarbaloin in Aloe species by micellar electrokinetic chromatography

Aloenin, barbaloin and isobarbaloin in JP Aloe, Aloe barbadensis (Aloe vera) and Aloe arborescens Miller var. natalensis Berger (Aloe arborescens Miller) were determined by micellar electrokinetic chromatography (MEKC) with 50 mM sodium dodecyl sulfate. Aloenin, barbaloin and isobarbaloin were well separated by MEKC and as little as 5.5 pg/11 nl of the three compounds could be detected. The determination took around 14 min.

Chemopreventive effects of Aloe arborescens on N-nitrosobis(2-oxopropyl)amine-induced pancreatic carcinogenesis in hamsters

The modification effects of freeze-dried aloe (Aloe arborescens) whole leaf powder during the initiation phase of carcinogenesis were investigated in hamsters treated with N-nitrosobis(2-oxopropyl)amine (BOP). Female Syrian hamsters were given four weekly subcutaneous injections of BOP at a dose of 10mg/kg and then given 0, 1 or 5% aloe in their diet for 5 weeks. At week 54 of the experiment, all surviving animals were sacrificed and development of neoplastic and preneoplastic lesions was assessed histopathologically. The incidences of pancreatic adenocarcinomas, atypical hyperplasias or total atypical hyperplasias plus adenocarcinomas were significantly (P<0.05) decreased with BOP+5% aloe, and that of adenocarcinomas were also significantly (P<0.05) reduced in the BOP+1% aloe as compared to the BOP alone group. Multiplicities of pancreatic adenocarcinomas, atypical hyperplasias or total lesions were also significantly (P<0.01 or P<0.05) lower in the BOP+5% aloe group than with the BOP alone. Quantitative data for neoplastic lesions in the lung, liver, gall bladder, kidney and urinary bladder of hamsters were not significantly different among the three groups. In a satellite experiment, pretreatment with aloe significantly (P<0.01) reduced the formation of O6-methyldeoxyguanosine in epithelial cells of pancreatic ducts as compared to the BOP alone value. Our results thus indicate that aloe prevents BOP-induced pancreatic neoplasia in hamsters in relation to decreased DNA adduct formation in the target tissue.

Surface expression and release of soluble forms of CD8 and CD23 in CD40- and IL-4-activated mononuclear cells from patients with Graves' disease (GD).

We investigated the effect of T cell‐dependent B cell activation on the surface expression and release of the soluble forms of CD8 and CD23 by peripheral blood mononuclear cells (PBMC) obtained from patients with GD, versus patients with Hashimotos thyroiditis, and normal controls. Incubating the PBMC with anti‐CD40 MoAbs and IL‐4 increased the soluble CD23 levels in cells from all three groups. An increase in the number of CD23+ cells was observed in the PBMC from the patients with GD, but not in PBMC from Hashimotos thyroiditis or controls. Less soluble CD8 was released from anti‐CD40 antibody and IL‐4‐stimulated PBMC obtained from patients with GD relative to those from the controls. In addition, the number of CD8+ cells was significantly reduced in stimulated PBMC from the GD patients relative to those from controls. Incubation of PBMC with anti‐CD40 antibody plus IL‐4 did not affect the proportions of CD4+, CD20+, Fas+CD4+, and Fas+CD8+ cells. The addition of T3 to cultured PBMC from controls did not reproduce the changes in CD23+ and CD8+ cells noted in the samples from GD patients. Thus, T cell‐dependent B cell activation, mediated by a CD40 pathway, may reduce the number of CD8+ cells, causing exacerbation of GD.

Developmental Changes in the NGF Content in the Brain of Young, Growing, Low-Birth-Weight Rats

The NGF content in each region of the brain of four-week-old rats was ranked in the decreasing order of cerebral cortex, hippocampus, cerebellum, midbrain/diencephalon, and pons/medulla ob-longata, and the NGF concentration, in the decreasing order of hippocampus, cerebral cortex, cerebellum, midbrain/diencephalon, and pons/medulla oblongata in both AFD and SFD groups. The NGF content and concentration in the cerebral cortex were about the same value at each age between those in the AFD and SFD groups. Those in the hippocampus were a little higher in the SFD group than in the AFD group at the ages of three and four weeks, unlike those in the other regions, where the values for the cerebellum, midbrain/diencephalon and pons/medulla oblongata tended to be somewhat higher in the AFD group than in the SFD group. The NGF concentrations in the hippocampus and cerebral cortex increased with growth: the concentration in the hippocampus at four weeks of age was about 4-fold of that at one week in the AFD group and about 5.7-fold of that at one week in the SFD group; and likewise the concentration in the cerebral cortex at four weeks of age was about 5.3-fold in the AFD group and about 7-fold in the SFD group. The NGF concentrations in the cerebellum decreased, and those in midbrain/diencephalon and pons/medulla oblongata hardly changed with growth in either AFD or SFD group. From these results NGF may have stronger implications for the neuronal growth in the hippocampus compared with those in the lower brain regions of the SFD rats.

Influences of Catecholamine Contents on Tetrahydrobiopterin Metabolism

Summary The influence of changes in catecholamine metabolism on tetrahydrobiopterin biosynthesis was investigated in cultured rat pheochromocytoma PC12 cells. The increase in the cellular dopamine content after treatment with the MAO-COMT inhibitor or dopamine produced decreases in the GTP-cy-clohydrolase I (GTPCH-I) activity and total biopterin content. On the contrary, the catecholamine increase after treatment with nerve growth factor produced increases in the GTPCH -I activity and total biopterin content. On the other hand, the decrease in the dopamine content after tyrosine hydroxylase (TH) inhibitor treatment produced decreases in the GTPCH-I activity and total biopterin content, but the catecholamine decrease (the DOPA content increased about 3.4-fold) after aromatic L-amino acid decarboxylase inhibitor treatment produced a decrease in the GTPCH-I activity. These results suggest that an increase in dopamine content that is not directly related to the action of TH plays a role in down-regulation of tetrahydrobiopterin biosynthesis and that when the changes in catecholamine metabolism are strongly associated with the action of TH, tetrahydrobiopterin biosynthesis is regulated depending on the necessity for TH.

Influence of an Aromatic Amino Acid Decarboxylase Inhibitor on GTP Cyclohydrolase I Activity in the Rat Brain

Summary Based on the hypothesis that catecholamine decreases may cause increases in biopterin, we measured the GTP cyclohydrolase I(GTPCH-I) activity and biopterin content in the cerebral cortex, midbrain/diencephalon, cerebeilum, pons/medulla oblongata, striatum , and hippocampus of brains from rats given NSDlOIS, an inhibitor for aromatic amino acid decarboxylase . The catecholamine contents decreased in all the regions tested. The changes in the GTPCH -I activity and bioptcrin content were different among the regions; they decreased in some regions contrary to expectations and increased in other regions. However, either the enzyme activity or biopterin content increased in the midbrain/ diencephalon and pons/ medulla oblongata, in which similar levels of catecholamines, GTPCH -I activity and biopterin were detected. These results suggest that for the midbrain/diencephalon and pons/medulla oblongata the surmise that a decrease in catecholamines causes an increase in the biopterin synthesis may be correct.