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.     

RP－HPLC法测定复合维生素B片中维生素B_1、B_2、B_6和烟酰胺的含量

用ＲＰ－ＨＰＬＣ法（固定相为μＢｏｎｄｐａｋ Ｃ１８柱，流动相为己烷磺酸钠冰醋酸液，紫外检测波长为２８０ｎｍ）同时测定出复合维生素Ｂ片中四个组分的含量，方法专属性强，省时；维生素Ｂ１、Ｂ２、Ｂ６和烟酰胺的平均回收率和平均相对标准偏差分别为１００．５％，２．０％；９８．０％，１．９％；１０１．８％，１．１％；１００．１％，２．１％（ｎ＝３）。     

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.     

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。     

HPLC法测定烟酰胺片的含量

建立烟酰胺片含量的HPLC测定方法。色谱柱为KF -C18柱 ;流动相为乙腈 -三乙胺溶液 (0 0 2 5mol·L-1,用磷酸调节pH至 3 0 ) (8∶92 ) ,流速为 1 0ml·min-1;检测波长 2 6 1nm ;吡嗪酰胺为内标物。烟酰胺在 8～ 5 6 μg·ml-1范围内呈良好的线性关系 ,平均回收率为 99 4 7% ,RSD =0 4 2 % (n =9)。方法简便 ,可靠 ,快速 ,准确 ,可用于测定烟酰胺片的含量。     

高效液相色谱法测定六合维生素丸中3种B族维生素含量

目的:采用离子对反相高效液相色谱法测定六合维生素丸中烟酰胺、维生素B2、维生素B13种水溶性维生素的含量。方法:以C18为色谱柱,0.005mol/L庚烷磺酸钠溶液(含0.5%冰醋酸和0.05%三乙胺)-甲醇(72∶28)为流动相,流速为1ml/min,检测波长为260nm。结果:烟酰胺、维生素B2、维生素B1的线性范围分别为0.3154～15.7700μg、0.05227～2.6135μg、0.4474～22.3700μg;方法的回收率在97.5%～99.2%,RSD为1.3%～1.8%。结论:本法简便,快速,为六合维生素丸产品的质量控制及多维类药物中水溶性维生素含量的测定提供了可靠依据。     

Evidence for increased NADPH-diaphorase-positive neurons in the central auditory system of the aged rat

Conclusions: The age-related increase in the production of nitric oxide (NO) suggests that this increase was related to neuron aging. Additional studies may provide information regarding aging-related changes in the central auditory system. Objectives: Although NO has been associated with aging, it is unclear whether specific areas of the central auditory system are involved. We therefore assayed aging-related changes in NADPH-diaphorase (NADPH-d), a selective histochemical marker for NO, in the neurons of the central auditory system and other brain regions. Materials and methods: The numbers of NADPH-d-stained neurons and the area and staining density of cell bodies were examined in aged (24 months old) and younger (4 months old) Wistar rats. Results: The number of NADPH-d-positive neurons in the inferior colliculus was significantly increased in aged rats (p<0.05), whereas the area of NADPH-d-positive neurons in all areas did not differ significantly between aged and younger rats (p>0.05). The staining densities of NADPH-d-positive neurons in the inferior colliculus, the auditory cortex, and the visual cortex were significantly greater in aged compared with younger rats (p<0.05).     

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.