1-Methylnicotinamide stimulates cell growth and inhibits hemoglobin synthesis in differentiating murine erythroleukemia cells

Exposure of murine erythroleukemia cells (MELCs) to nicotinamide (NA) or its synthetic analog N′-methylnicotinamide (N′-MN) reduces cell growth and induces terminal differentiation, marked by increased heme and globin accumulation. On the contrary, 1-methylnicotinamide (1-MN), the primary metabolite of excess NA, was found to stimulate cell growth and reduce spontaneous differentiation of cultured MELCs. Log phase MELCs exhibited up to 50% higher cell density above untreated cells when cultured for up to 96 h with 2.5 mM 1-MN. When combined with NA or several chemically-unrelated inducers of hemoglobin synthesis in cultured MELCs, 1-MN reduced the globin mRNA levels and heme accumulation by 40–80%. 1-MN was able to inhibit heme production if present during only the first 24–48 h after NA exposure. Pre-treatment with 1-MN could not confer resistance of cells to effects of NA, suggesting the inhibition is reversible. Commitment to differentiate in semisolid medium by the most potent inducer, 5 mM N′-MN, was inhibited up to 95% by 2.5 mM concentrations of 1-MN. It appears that 1-MN has opposing effects on growth and induction of differentiation than those seen in MELC cultures exposed to NA or N′-MN.     

The coenzyme nicotinamide adenine dinucleotide (NADH) improves the disability of Parkinsonian patients

Summary The coenzyme nicotinamide adenine dinucleotide (NADH) has been used in an open label trial as novel medication in 34 patients with Parkinson's disease, using an intravenous administration technique. In all patients a beneficial clinical effect was observed. 21 patients (61.7%) showed a very good (better than 30%) improvement of disability, 13 patients (38.3%) a moderate (up to 30%) improvement. Concomitant with the improvement of the disability the urine level of homovanillic acid (HVA) increased significantly in all patients (in some patients by more than a 100%). The daily on phases of the patients could be increased from 2 up to 9 hours in the individual patients by NADH administration.     

Biochemical characterization of I-Ak proteins from mutant antigen-presenting B-cell--B-lymphoma hybridomas

Chemically induced mutants of an I-Ak,d expressing antigen-presenting B-cell--B-lymphoma hybridoma have recently been generated by immunoselection in vitro and were found to possess alterations in some of their serologically and functionally defined I-Ak region dependent functions. In order to identify at the structural level the origin of the differences in serological and functional properties of these mutants, I-Ak molecules from several of these mutant hybridomas were compared biochemically to wild-type I-Ak polypeptides by two-dimensional gel electrophoresis and high-pressure liquid chromatographic tryptic peptide analyses. Two-dimensional gel electrophoresis indicated that no major structural alterations, resulting in changes in mol. wt or charge, had occurred in the Ak alpha or Ak beta polypeptides from the mutant cells. Likewise, Ak alpha peptide maps of the mutants were indistinguishable from the normal Ak alpha peptide maps. However, two of the three mutants studied did exhibit one additional peptide in their Ak beta peptide maps. These results suggest that the major deficiencies in T-cell-activating functions of these mutants are a result of a limited alteration in the Ak beta polypeptide primary structure.     

NAD-Sepharose 6MB亲和胶的制备及在2,5-二酮基-D-葡萄糖酸还原酶纯化中的应用

目的制备NAD亲和胶,用于分离纯化2,5-二酮基-D-葡萄糖酸还原酶。方法将NAD通过丁二酸二酰肼与溴化氰活化的Sepharose6MB胶联结,制得NAD亲和胶。从棒杆菌细胞中提取的2,5-二酮基-D-葡萄糖酸还原酶粗酶液用NAD亲和胶进行亲和层析纯化。结果NAD的结合率为71．67％;亲和层析回收率为77．27％;酶的比活提高了1．1倍。结论以NAD为配基的亲和胶用于纯化以NADPH为辅酶的2,5-DKG还原酶行之有效。     

Lifespan extension by n-butanol extract from seed of Platycladus orientalis in Caenorhabditis elegans

Aim of the study

As a traditional Chinese medicine, seed of Platycladus orientalis(Linnaeus) Franco has been extensively used as a tonic and sedative remedy. The present study was conducted to investigate whether lifespan was extended and the mechanisms of n-butanol extract from seed of Platycladus orientalis (BSPO) in Caenorhabditis elegans. The findings could provide the pharmacological basis for a treatment in traditional medicine.

Materials and methods

Lifespan extension by BSPO was evaluated under normal culture conditions and in a stress test. A possible mechanism of the anti-aging effect of BSPO, a change in the stress-resistance of related proteins, was also investigated in C. elegans.

Results

It has been shown that BSPO could significantly extend lifespan of C. elegans in a concentration dependent manner under normal culture conditions and stress. Further studies demonstrated that BSPO treatment significantly decreased reactive oxygen species (ROS) accumulation, up-regulated resistance to stress of related proteins, including glutathione S-transferase-4 (GST-4) and heat shock protein-16.2 (HSP-16.2), and reduced the amount of lipofuscin in transgenic C. elegans.

Conclusion

These results indicated that BSPO extended the lifespan, which could be attributed to its direct ROS scavenging activity, reducing the amount of lipofuscin and increasing the expression of gens associated with resistance to stress. These obtained data provided valuable support for traditional clinical practice to extend lifespan and to provide tonic remedy.     

苯肾上腺素对大鼠成骨细胞放射损伤的保护作用

目的:探讨苯肾上腺素对放射损伤大鼠成骨细胞的细胞形态以及烟酰胺磷酸核糖转移酶(Nampt)mRNA表达水平的影响,阐明苯肾上腺素对其可能的保护作用机制。方法:组织块法培养大鼠颅骨成骨细胞,随机分为空白对照组、苯肾上腺素组、单纯照射组和苯肾上腺素+照射组。苯肾上腺素组在照射前0.5 h以100 mmol·L^-1苯肾上腺素孵育成骨细胞,照射组给予成骨细胞8 Gy X射线照射。照射后8、16、32和64 h在倒置显微镜下观察并分别收集细胞,提取细胞总RNA,应用RT-PCR法检测成骨细胞Nampt mRNA表达水平。结果:倒置显微镜下,与空白对照组比较,苯肾上腺素组成骨细胞形态、数量未见明显改变;单纯照射组细胞形态发生明显皱缩,尤以8 h明显,细胞数量在8、16、32和64 h时分别是对照组的0.82、0.37、0.24和0.21倍;苯肾上腺素+照射组在照射8和16 h后细胞皱缩,32 h后其形态恢复,在8、16、32和64 h后其数量分别为空白对照组的0.91、0.83、0.72和0.75倍,是单纯照射组的1.09、2.24、3.00和3.60倍。RT-PCR法检测,在照射8、16、32和64 h后,单纯照射组、苯肾上腺素+照射组Nampt mRNA表达水平较空白组明显减少(P<0.01),苯肾上腺素+照射组较单纯照射组明显增加(P<0.01)。结论:苯肾上腺素可减轻电离辐射导致的大鼠成骨细胞萎缩,并上调Nampt mRNA表达水平,其对成骨细胞放射损伤的保护作用可能与上调Nampt mRNA表达水平有关。     

尼克酰胺腺嘌呤二核苷酸磷酸氧化酶在血管性认知障碍中的作用及其机制的研究进展

氧化应激(OS)是导致血管性认知障碍(VCl)的因素之一.尼克酰胺腺嘌呤二核苷酸磷酸(NADPH)氧化酶(NOX)产生的活性氧(ROS)是VCI重要的致病分子.VCI的危险因素如高血糖及缺血/再灌注等在上游增加NOX的活化;其他危险因素如高龄、高血压及卒中是NOX依赖ROS产生的下游损伤.VCI的成因包括与NOX相关的...     

Effects of dark chocolate on endothelial function in patients with non-alcoholic steatohepatitis

Background and Aim

Oxidative stress plays a pivotal role in inducing endothelial dysfunction and progression from simple fatty liver steatosis (FLD) to non-alcoholic steatohepatitis (NASH). Polyphenols could reduce oxidative stress and restore endothelial function by inhibiting the nicotinamide-adenine-dinucleotide-phosphate (NADPH) oxidase isoform Nox2.The aim of this study was to assess endothelial function and oxidative stress in a population affected by simple FLD and NASH. Furthermore, we analysed the effect of high vs low content of cocoa polyphenols on endothelial function and oxidative stress in patients with NASH.

Nicotinamide and insulin secretion in normal subjects

Summary Nicotinamide has been given both before and after clinical onset of Type 1 (insulin-dependent) diabetes mellitus in an attempt to prolong beta-cell survival. Nicotinic acid, structurally similar to nicotinamide, induces insulin resistance and increases insulin secretion in healthy individuals. It is not known if nicotinamide has similar effects. Since insulin secretion, as measured by the acute insulin response to intravenous glucose, is used to predict diabetes and to monitor therapy, the effects of nicotinamide must be established before trials in individuals at high risk of progression to Type 1 diabetes can be interpreted. Intravenous tolerance tests were performed according to the ICARUS standard protocol in 10 healthy, adult subjects (age 32±5.7 years) before and after 14 days of treatment with nicotinamide 25 mg · kg^–1 · day^–1. The acute insulin response after nicotinamide did not differ from the control study, whether measured as the incremental 0–10 min insulin area (278±142 vs 298±130mU · l^–1 · 10 min^–1) or as the 1±3 min insulin level (78±39 vs 81±44 mU/l). The late insulin response was equally unaffected, as were basal insulin (5.2±1.6 vs 5.6±2.1 mU/l) and glucose (5.0±0.4 vs 4.9±0.2 mmol/l) levels and glucose disposal rates (1.98±0.88 vs 2.04±0.68%/min). Nicotinamide does not affect insulin secretion and glucose kinetics in normal subjects, confirming its suitability for trials designed to delay or prevent the onset of Type 1 diabetes.     

Frequent HPRT mutations in paroxysmal nocturnal haemoglobinuria reflect T cell clonal expansion, not genomic instability

Paroxysmal nocturnal haemoglobinuria (PNH) results from acquired mutations in the PIG-A gene of an haematopoietic stem cell, leading to defective biosynthesis of glycosylphosphatidylinositol (GPI) anchors and deficient expression of GPI-anchored proteins on the surface of the cell's progeny. Some laboratory and clinical findings have suggested genomic instability to be intrinsic in PNH; this possibility has been supported by mutation analysis of hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene abnormalities. However, the HPRT assay examines lymphocytes in peripheral blood (PB), and T cells may be related to the pathophysiology of PNH. We analysed the molecular and functional features of HPRT mutants in PB mononuclear cells from eleven PNH patients. CD8 T cells predominated in these samples; approximately half of the CD8 cells lacked GPI-anchored protein expression, while only a small proportion of CD4 cells appeared to derive from the PNH clone. The HPRT mutant frequency (Mf) in T lymphocytes from PNH patients was significantly higher than in healthy controls. The majority of the mutant T lymphocyte clones were of CD4 phenotype, and they had phenotypically normal GPI-anchored protein expression. In PNH patients, the majority of HPRT mutant clones were contained within the Vbeta2 T cell receptor (TCR) subfamily, which was oligoclonal by complementarity-determining region three (CDR3) size analysis. Our results are more consistent with detection of uniform populations of expanded T cell clones, which presumably acquired HPRT mutations during antigen-driven cell proliferation, and not due to an increased Mf in PNH. HPRT mutant analysis does not support underlying genomic instability in PNH.