HPLC法同时测定多维元素片中维生素A和维生素E的含量

目的建立高效液相色谱(HPLC)法同时测定多维元素片中维生素A和维生素E的含量。方法采用C18色谱柱(250mm×4.6mm,5μm);流动相为甲醇-水(98∶2);流速为1.0mL·min-1;检测波长为265nm;柱温为25℃。结果维生素A和维生素E的线性关系良好,相关系数(r)均大于0.999 9;专属性强,维生素A、维生素E与药品中其他成分之间均有良好的分离度;稳定性和精密度良好,相对标准偏差(RSD值)均小于1.0%;回收率良好,回收率在91.07%~92.85%之间;稳定性能满足实验要求。结论该法可同时定性和定量分析多维元素片中的维生素A和维生素E,其方法的精密度、回收率和检出限能满足实际检测要求,可用于该制剂中维生素A和维生素E的监测。     

A comparison of the nutrient content of uncooked and cooked lean from New Zealand beef and lamb

The composition in terms of proximate analysis, cholesterol, vitamins, minerals, and fatty acids of the lean tissue of 17 beef cuts and 18 lamb cuts was determined on within-cut composite samples (each containing lean tissue from at least 7 animals), following the knife-separation of raw and cooked cuts into lean, fat, and bone. Composite lean samples for 4 beef cuts and 4 lamb cuts were also analysed for amino-acid composition. For analysis, different cuts were the experimental unit as individual animal data were not available. The composition of lean from beef and lamb was shown to be highly desirable with a high nutrient density (mg/kJ) for many nutrients. Although lean from beef and lamb were very similar in many respects, several significant differences were detected. Changes in composition with cooking were largely eliminated when considered on a dry-matter basis, but proportions of the n-3 and n-6 polyunsaturated fatty acids increased with cooking (P < 0.05). The amino acid composition was similar for lean from beef and lamb but showed small deviations from recommended patterns for human nutrition with branched chain amino acids being limiting.     

Vitamin supplements among women with adenomatous polyps and cancer of the colon

Chemoprevention of various epithelial cancers with vitamins or minerals has been the subject of multiple intervention trials to assess the impact of supplementation. These include several trials in patients with adenomatous polyps of the colon, a precursor lesion for colon cancer. The authors interviewed 255 women who underwent colonoscopy at Columbia Presbyterian Medical Center between 1983 and 1985 with a telephone-administered structured questionnaire. Eleven interviews were excluded for various reasons. Overall, 57.7 percent of the 244 interviewees used vitamin pills on a regular basis (at least once a week for a year); 6.6 percent of the interviewees used vitamin A, 20.7 percent used vitamin C, and 16.2 percent used vitamin E. There were no statistically significant differences in vitamin usage among women with adenomatous polyps of the colon (105 cases), women with colon cancer (56 cases), and women without colonic neoplasia (83 cases). Despite widespread use of supplementary vitamins, this study failed to demonstrate major benefits in preventing colon polyps or cancer. Read in part at the Tenth Meeting of the American Society for Preventive Oncology, Bethesda, Maryland, March 7, 1986. Supported by NCI Grant No.CA37196, an American Cancer Society Junior Faculty Fellowship (AIN), a grant from the Andrew Mellon Foundation, and an internship from the Health Research Training Program of the NYC Department of Health (CMJ).     

Vitamin and calcium supplement use is associated with decreased adenoma recurrence in patients with a previous history of neoplasia

INTRODUCTION: Although some have suggested that certain vitamins or calcium supplements may reduce adenoma recurrence, our own prior retrospective study found no such effects. The purpose of this case-control study was to further investigate whether regular vitamin or calcium supplement intake influenced the incidence of recurrent adenomatous polyps in patients with previous neoplasia who were undergoing follow-up colonoscopy. METHODS: This study enrolled 1,162 patients who underwent colonoscopy by one of three surgeons at Columbia-Presbyterian Medical Center in New York City between March 1993 and February 1997. Of these patients 448 (250 males) had a previous diagnosis of colorectal neoplasia (cancer, adenomas, or dysplasia). Of these, 183 (40.8 percent) had an adenoma at the index colonoscopy. Information was collected on personal and family history of colonic diseases, cigarette smoking, medication, and vitamin and micronutrient supplement usage on a questionnaire that was completed by the patients before the colonoscopy. Odds ratios were obtained by unconditional logistic regression analysis, adjusting for age and gender, and used adenoma recurrence at index colonoscopy as the outcome. RESULTS: The mean interval between colonoscopic examinations was 37 months for the recurrent adenoma group and 38 months for the nonrecurrent group of patients (P = not significant). In this case-control study we found a protective effect for the use of vitamin supplements in general (any vitamin) on the recurrence of adenomas (odds ratio, 0.41; 95 percent confidence interval, 0.27–0.61). Specifically, this protective effect was observed for the use of multivitamins (odds ratio, 0.47; 95 percent confidence interval, 0.31–0.72), vitamin E (odds ratio, 0.62; 95 percent confidence interval, 0.39–0.98), and for calcium supplementation (odds ratio, 0.51; 95 percent confidence interval, 0.27–0.96). Nonsignificant protective effects were noted for carotene/vitamin A, vitamin D, and vitamin C. CONCLUSIONS: The use of multivitamins, vitamin E, and calcium supplements were found to be associated with a lower incidence of recurrent adenomas in a population of patients with history of previous colonic neoplasia. Prospective, randomized trials are needed to better assess the impact of these agents and to determine whether the use of these supplements is associated with a protective effect against recurrent adenomas.Supported by United States Surgical Corporation, Norwalk, Connecticut.Read at the meeting of The American Society of Colon and Rectal Surgeons, San Antonio, Texas, May 2 to 7, 1998.     

Differential relationship of vitamin A and E levels in methylnitrosourea-induced Sprague-Dawley rats following prolonged feeding of fatty diets enriched with the vitamins

Summary Prolonged supplementation of vitamins A and E (2500 IU and 11.3 IU/rat daily) in 10.3% and 21.6% fatty diets administered to methylnitrosourea-induced Sprague-Dawley rats caused alterations in plasma and liver levels of both vitamins as well as of the total lipids. Liver vitamin A levels increased steadily (more than four-fold) until termination of the experiment, whereas plasma vitamin A levels only showed a minor increase at the end of the study in comparison to rats fed a standard diet. Liver vitamin E levels initially showed no difference from those of rats treated with a standard diet, and were decreased at the end of the experiment, whereas the respective plasma levels were increased throughout the study, only showing a decrease relative to initial values at termination of the experiment. Plasma total lipids increased with age and following supplementation of the vitamins in the high-fat diet, whereas liver total lipids were influenced less by aging than by the fat and vitamin contents of the respective diets. The observed alterations were, however, not related to significant chemopreventive activity of the vitamins A and E contained in high-fat diets.Dedicated to Professor Dr. Dietrich Schmähl on the occasion of his 65th birthday     

八维钙锌片中维生素D_2含量测定方法的改进

目的改进八维钙锌片中维生素D2含量测定的方法。方法采用HPLC法,以Thermo硅胶(250 mm×4.6 mm,5μm)为色谱柱;流动相:正己烷-异丙醇(110∶1);流速:1.0 mL·min-1;检测波长:254 nm;柱温:35℃。结果维生素D2的线性范围为质量浓度0.5~10 mg.L-1,相关系数为0.995 8,回收率为100.8%(n=9)。结论该方法简便准确,重复性好,可作为控制八维钙锌片中维生素D2的含量测定方法。