We examined the effect of vitamin B6 deficiency on glyoxylate metabolism and hepatic alanine: glyoxylate aminotransferase (AGT) activity in rats with normal or high glyoxylate intake. Male rats were divided into four groups: a control group, a vitamin B6-free diet group, a glyoxylate water group, and a vitamin B6-free diet + glyoxylate water group. Each group was given special diet (control or vitamin B6-deficient diet) and drinking water (plain or 0.5% glyoxylate water) for 4 weeks, after which biochemical parameters and hepatic AGT mRNA level were measured. Compared with control rats, the urinary oxalate/creatinine ratio was higher in each of the other 3 groups. The urinary glycolate/creatinine ratio was also higher in the vitamin B6-free diet group and the vitamin B6-free diet + glyoxylate water group than the control group, while the urinary glycine/creatinine and citrate/creatinine ratio was lower in both groups. The hepatic AGT mRNA level was reduced in the vitamin B6-free diet group, but was increased in the glyoxylate water group than the control group. These results suggest that vitamin B6 is necessary for glyoxylate metabolism as a coenzyme of AGT. Especially in the presence of a high glyoxylate intake, vitamin B6 deficiency leads to severe hyperoxaluria and hypocituria.
Using a DNA microarray, we analyzed about 16,600 genes for changes in expression associated with the differentiation of human promyelocytic leukemia HL-60 cells induced by 1α,25-dihydroxyvitamin D3 (DVD). Many of the up-regulated genes could be correlated to differentiation-associated changes toward a monocyte/macrophage lineage, and many down-regulated genes could be correlated to repressed cell growth. The present study revealed the down-regulated gene expression of importins and exportins 1, 5, 7, and exportin-tRNA. Thus, the present results confirmed our previous findings of down-regulation of exportin 1 and exportin-tRNA by DVD. Gene expression of exportin 6 is suggested to be regulated differently from that of exportins 1, 5, 7, and exportin-tRNA. The down-regulation of nuclear transport factors may be deeply associated with the differentiation of HL-60 cells induced by DVD.
The onset of some adult diseases, e.g., cardiovascular disease, is known to be associated with lifestyles in childhood. The objective of this study was to clarify the relationship between total sleep duration (TSD) and systolic and diastolic blood pressure (SBP and DBP) among 117 children at ages 5-6 years. Parents reported their children's typical bedtimes and wake times for weekdays, and questions about mandatory nap times were answered by the preschool teachers. In the children, the mean TSD, SBP, and DBP were 624 ± 57 (standard deviation) min, 99 ± 10 mmHg, and 62 ± 9 mmHg, respectively. When the children were divided into quartile groups based on TSD, the SBP was significantly higher in the highest group (TSD > 660 min) than in the lowest group (TSD ≤ 585 min). The TSD was significantly correlated with SBP (r = 0.265) but not with DBP (r = 0.105), these relationships were similar when TSD and possible confounders such as age and body mass index were set as independent variables of multiple regression analysis. These findings suggest that sleep duration in preschool children is associated with SBP, and extremely short or long sleep may invite subclinical health problems.
The majority of research for the calcitonin gene-related peptide (CGRP) in the stomach has been devoted to the submucosal blood flow, and only slight attention has been paid to its involvement in the gastric epithelial function. In this study, we examined the age-related change in the CGRPcontaining nerves and its effects on the mucus metabolism. We compared the immunoreactivity for CGRP in the gastric mucosa of 7-week-old rats (young) to that of 52-week-old animals (middle-aged). The effects of CGRP on the mucin biosynthesis were compared using the stomachs from both young and middle-aged rats. The nitric oxide synthase (NOS) activity was measured in the surface and deep mucosa of the gastric corpus. The density of the CGRP nerve fibers was reduced in both the lamina propria and submucosa of the middle-aged rats compared to the young rats. CGRP stimulated the mucin biosynthesis in the cultured corpus mucosa from the 7-week-old rats, but not from the 52-week-old rats. The total NOS activity of the surface layer in the corpus mucosa was markedly reduced in the middle-aged rats compared to the young rats. These findings demonstrate the age-dependent reduction in the CGRP-induced mucin biosynthesis, as well as in the density of the CGRP fibers in the rat stomach. The decreased NOS activity in the surface layer of the oxyntic mucosa in the aged rats may also be a principal cause for the lack of regulation of the mucin biosynthesis by CGRP.
A new cytochemical method was devised in order to visualize Cu2+ ions in the synaptic area after their intracellular penetration during nerve stimulation of the frog neuromuscular junction (NMJ). The motor nerves were stimulated in presence of Cu2+. After total blockade of the neuromuscular junction, the tissue was treated by ferrocyanide, a precipitating agent of Cu2+, and fixed for optical and electron microscopic observation. The oxidoreductase-like catalytic activity of the copper ferrocyanide precipitate was used to amplify the cytochemical staining by a treatment with diaminobenzidine and H2O2, after permeabilization of cell membranes by Triton X-100. At optical level, an intense staining was observed in the synaptic area. Application of d-tubocurarine (d-TC), a selective inhibitor of nicotinic acetylcholine receptors (nAChRs), markedly reduced the staining. No reaction could be observed in absence of membrane permeabilization. These results suggest that Cu2+ was localized in the cytoplasm of muscle cells after its penetration through nAChRs. At electron microscopic level, cytochemical reaction was found in the cytoplasm of muscle cells near the postsynaptic membrane, and in a few synaptic vesicles in the vicinity of the active zone. This method may be used for the identification of cholinergic inputs in central and peripheral nerve systems and, generally speaking, for the detection of synaptic activity elicited by specific nerve stimulation.
Chloroquine, quinine, artemisinin, and pyrimethamine are generally considered safe drugs for treatment of malaria during pregnancy; however, high doses of these drugs are detrimental with adverse outcome of pregnancy. Since antimalarial drugs interaction with placental cells has not been addressed, in this study, we employed a non-radioactive proliferation assay and lactate dehyrogenase (LDH) release assays to investigate the effect of these drugs on JAR trophoblastic cell survival. All drug treatment resulted in inhibition of cell proliferation in a dose-dependent fashion (p < 0.05) with IC50 at 6.96, 6.49, 6.69, and 6.89 μg/mL for chloroquine, quinine, artemisinin and pyrimethamine, respectively. In addition, the inhibition of cell proliferation was accompanied by increased cytotoxicity. Analysis of the progression of the cell cycle showed that these drugs triggered G0/G1 and S phase arrest. Furthermore, these antimalarial drugs induced apoptotic cell death as visualized by DNA fragmentation analysis techniques. Findings in this study revealed that cytotoxicity of these drugs on human placental trophoblast is mediated by both cell cycle arrest and induction of cell death and this could have important implications for the use of antimalarial drugs for treating malaria during pregnancy.
The aim of this study was to evaluate the healing of class III furcation defects following transplantation of proliferating tissue derived from periodontal ligament (pPDL). Two weeks after removing alveolar bone, pPDL was excised. Class III furcation defects were created in the mandibular premolars. pPDL was transplanted into the furcation defects in the experimental group, while no treatment was performed on the furcation defects in the controls. Two, four and eight weeks after surgery, histologic examination, quantitative RT-PCR, and immunohistochemistry were carried out. bFGF and VEGF mRNA showed a significant increase in pPDL. In the pPDL treatment group, new cementum regenerated around almost the entire circumference of the furcation, with new bone filling most of the defect, while the control group presented epithelial downgrowth and defects filled with connective tissue. These results provide histological evidence that pPDL plays an important role in wound healing by promoting periodontal regeneration in class III furcation defects.