Flour infested with Tribolium castaneum, biscuits made of this flour, and 1,4-benzoquinone induce neoplastic lesions in Swiss albino mice.

The carcinogenic effect of flour infested with beetles (Tribolium castaneum), biscuits made of this flour, and 1,4-benzoquinone (a quinoid secretion of this beetle) was investigated using Swiss albino mice. Force feeding flour infested with T. castaneum induced liver and spleen tumors (lympholeukemia) in 35.2% of the animals. The tumor incidence was 29% in mice force fed biscuits made of infested flour, and the tumors were located in the liver (lympholeukemia) and breast (adenocarcinoma type A). In animals fed 1,4-benzoquinone, the tumor incidence was 33.6%, and the tumors were located in the liver and spleen (lympholeukemia). It is speculated that 1,4-benzoquinone, alone or in combination with other quinoid secretions of the beetles present in the flour, may be responsible for tumor induction in the organs of mice.     

Experimental removal of sexual selection leads to decreased investment in an immune component in female Tribolium castaneum

Because of divergent selection acting on males and females arising from different life-history strategies, polyandry can be expected to promote sexual dimorphism of investment into immune function. In previous work we have established the existence of such divergence within populations where males and females are exposed to varying degrees of polyandry. We here test whether the removal of sexual selection via enforced monogamy generates males and females that have similar levels of investment in immune function. To test this prediction experimentally, we measured differences between the sexes in a key immune measurement (phenoloxidase (PO) activity) and resistance to the microsporidian Paranosema whitei in Tribolium castaneum lines that evolved under monogamous (sexual selection absent) vs polyandrous (sexual selection present) mating systems. At generation 49, all selected lines were simultaneously assessed for PO activity and resistance to their natural parasite P. whitei after two generations of relaxed selection. We found that the polyandrous regime was associated with a clear dimorphism in immune function: females had significantly higher PO activities than males in these lines. In contrast, there was no such difference between the sexes in the lines evolving under the monogamous regime. Survival in the infection experiment did not differ between mating systems or sexes. Removing sexual selection via enforced monogamy thus seems to erase intersexual differences in immunity investment. We suggest that higher PO activities in females that have evolved under sexual selection might be driven by the increased risk of infections and/or injuries associated with exposure to multiple males.     

亚硝酸钠诱导L929细胞增殖毒物兴奋效应

目的采用体外细胞毒性检测方法研究亚硝酸钠(NaNO₂)对L929细胞增殖的影响,探讨在此过程中遗传物质的损伤情况。方法体外培养L929细胞,用溴化四氮唑蓝法检测不同浓度NaNO₂对细胞增殖的影响;并采用单细胞凝胶电泳技术及KCl-十二烷基磺酸钠沉淀法(K-SDS)检测NaNO₂对L929细胞DNA损伤及DNA-蛋白质交联的作用。结果 NaNO₂处理L929细胞48h后,细胞增殖出现毒物兴奋效应(hormesis),其剂量范围约为0～0.0384mg/L;染毒剂量为0.02、1 500 mg/L时,细胞尾长分别为(2.72±1.99)、(3.26±3.09)μm,尾DNA%分别为(7.87±6.63)%及(7.75±4.90)%,Olive尾矩分别为(0.80±0.64)及(0.79±0.64),与阴性对照组〔(1.83±1.08)μm、(6.07±3.59)%、(0.43±0.28)〕比较,差异均有统计学意义(P<0.05);2、20、1 500 mg/L剂量组的DNA-蛋白质交联系数大于阴性对照组(P<0.05),且呈现剂量-效应关系。结论 NaNO₂可诱导L929细胞出现毒物兴奋效应,并且在其剂量范围内可诱导细胞遗传物质的断裂性损伤。     

A new TK model approach to assess the effect of migration on copper toxicokinetics in inbred populations of the flour beetle, <Emphasis Type="Italic">Tribolium castaneum</Emphasis>

The aim of the study was to determine the influence of migration on copper (Cu) kinetics of male Tribolium castaneum after 25 generations of exposure for Cu-adapted and non-Cu-adapted inbred lines. Adapted lines were kept on a flour medium contaminated with 1000 mg Cu kg^?1. A medium contaminated with 2000 mg Cu kg^?1 of copper was used during the intoxication phase. Based on our data and literature reports, we introduced a new two-phase four-stage toxicokinetics (TK) model. The intoxication phase was successfully divided into three stages with separate assimilation rate constant (k_a) and elimination rate constant (k_e) values. The influence of migration was examined by comparing k_a and k_e parameters confidence intervals. In non-contaminated environments, migrants significantly increased k_a and k_e values in the second stage. Migrants decreased the maximum Cu accumulation observed in the experiment. The results indicated that the TK model must show high goodness-of-fit to be a useful tool for comparing treatments.     

Malvidin-3-glucoside bioavailability in humans after ingestion of red wine, dealcoholized red wine and red grape juice

Summary Background & Aims Dietary polyphenols, including anthocyanins, are suggested to be involved in the protective effects of red wine against cardiovascular diseases. Very little data are available concerning the bioavailability of anthocyanins, major sources of red pigmentation in red wine. The aim of this study was to compare changes in plasma malvidin-3-glucoside (M-3-G), a red wine anthocyanin, and its urinary excretion after ingestion of red wine, dealcoholized red wine and red grape juice. Design Six healthy male subjects were studied in a randomized cross over setting in a human nutrition research unit under controlled conditions. All subject consumed 500 mL of each beverage on separate days providing the following M-3-G quantities: red wine 68 mg, dealcoholized red wine 58 mg, and red grape juice 117 mg. M-3-G was measured by HPLC and photodiode detection. Results M-3-G was found in plasma and urine after ingestion of all the beverages studied. The aglycon, sulfate or glucuronate conjugates of M-3-G were not detected in plasma and urine. Increases in plasma M-3-G concentrations were not significantly different after the consumption of either red wine or dealcoholized red wine and were about two times less than those measured after consumption of red grape juice. This difference may be caused by the about two times higher M-3-G concentration determined in red grape juice. Area under the plasma concentration curves were as follows: 288±127nmol × h/L (red wine), 214±124nmol × h/L (dealcoholized red wine) and 662±210 nmol × h/L (red grape juice) and showed a linear relationship with the amount of anthocyanin consumed (mean±SD). Conclusions M-3-G is poorly absorbed after a single ingestion of red wine, dealcoholized red wine, or red grape juice and seems to be differentially metabolized as compared to other red grape polyphenols. Our results suggest that not anthocyanins such as M-3-G themselves but rather not yet identified anthocyanin metabolites and/or other polyphenols in red wine might be responsible for the observed antioxidant and health effects in vivo in subjects consuming red wine. Received: 28 May 2001, Accepted: 17 July 2001     

Wheat flour fortification is unlikely to benefit the neediest in Guatemala

The potential impact of wheat flour fortification with iron and folic acid was assessed using data about food purchases from the nationally representative 2000 Guatemalan Living Standards Measurement Survey. Of 7265 households, 35% were indigenous and 57% rural; 11% were extremely poor, 35% were poor, and 54% were nonpoor. The percentage of households that purchased wheat flour, sweet bread, French rolls, and sliced bread in the previous 15 d was 10, 88, 59, and 11%, respectively. The median amount of fortified wheat flour equivalents in purchased foods was 50 g/d per adult equivalent; fortified wheat flour equivalents were 7, 25, and 110 g/d for the poverty groups, 16 g/d in indigenous households and 24 g/d in rural households. Wheat flour fortification contributed 2.3 mg/d of iron and 90 microg/d of folic acid per adult equivalent. Assuming 5% bioavailability, wheat flour fortification provided 2% of the recommended dietary allowance (RDA) and 6% of estimated average requirement (EAR) iron levels for women of reproductive age; values were 1, 3, and 12% of EAR levels for the poverty groups, respectively. Wheat flour fortification met 26% of folic acid RDA and 33% of EAR levels for women; values were 5, 16, and 71% of EAR levels for the poverty groups, respectively. In conclusion, the impact of fortification is likely to be substantial for folate status in nonpoor and urban women but limited in the case of iron status among all social groups. The poorest, rural, indigenous populations who suffer the highest burden of nutritional deficiencies likely benefit least from wheat flour fortification.     

The glucose intolerance induced by caffeinated coffee ingestion is less pronounced than that due to alkaloid caffeine in men

Although acute alkaloid caffeine (CAF) ingestion results in an impaired glucose tolerance, chronic coffee (RCOF) ingestion decreases the risk of developing type 2 diabetes. This study examines the hypothesis that CAF ingestion impairs glucose tolerance to a greater extent than RCOF and that the ingestion of decaffeinated coffee (DECAF) results in a positive effect. Eleven healthy males underwent 4 double-blinded randomized trials. Each trial included the ingestion of either: 1) CAF in capsule form (4.45 mg/kg body weight), 2) RCOF (4.45 mg/kg body weight caffeine), 3) dextrose (placebo, PL) in capsule form, or 4) DECAF (equal in volume to the RCOF trial), followed 1-h later by a 2-h oral glucose tolerance test. Blood samples were collected at baseline (-30), 0 (time of treatment ingestion), 60 (initiation of oral glucose tolerance test), 75, 90, 120, 150, and 180 min. Area under the curve for glucose and insulin were higher (P < or = 0.05) following CAF than both PL and DECAF and, although a similar trend (P = 0.07) was observed following RCOF compared with DECAF, the effect was less pronounced. Interestingly, DECAF resulted in a 50% lower glucose response (P < or = 0.05) than PL, suggesting that the effects of PL and DECAF on glucose tolerance are not the same. These findings suggest that the effects of CAF and RCOF are not identical and may provide a partial explanation as to why acute CAF ingestion impairs glucose tolerance while chronic RCOF ingestion protects against type 2 diabetes.     

Control of vitamin A deficiency disorders through fortification of cassava flour with red palm oil: A case study of Kigoma district,Tanzania

Vitamin A deficiency (VAD) is one of the public health problems in Tanzania particularly among preschool children. Several approaches have been suggested for the control VAD in developing countries among which, fortification of locally produced staples with vitamin A or provitamin A was noted to be viable and sustainable. This study was conducted in Kigoma district of Tanzania as part of the efforts to fortify the locally produced cassava flour with an underutilized provitamin A rich food—red palm oil. Fortification was incorporated as part of the traditional processing practice for cassava flour. Results of a feeding program with the enriched cassava flour involving 162 preschool children indicated a significant (p<0.05) decrease in the prevalence of VAD (plasma retinol level > 20 μg/dL). Prevalence of VAD among preschool children in the pilot villages decreased from 53.0% (range 23.1–72.7% plasma retinol levels 17.9–21.7 μg/dL) to 8.5% (range 5.5–9.8% plasma retinol levels 21.4–21.9 μg/dL) at the end of the program. The children also gained more weight (range 5.9–6.5 kg) compared to their counterparts in the control group (range 3.8–4.2 kg). The pregnant and lactating women who participated in the program recorded a 12.6% (range 11.9–14.0%) increase in their plasma retinol concentrations compared to an increase of 3.5% (range 3.2–3.7%) in the control group. Average plasma retinol concentrations were significantly (p<0.05) higher among women in the pilot villages (mean 22.3 μg/dL; range 19.0–24.5 μg/dL) compared to their counterparts in the control villages (mean 20.3 μg/dL; range 19.8–20.8 μg/dL). Results of sensory and acceptability evaluation of the meals prepared from the fortified cassava flour showed that the product was highly liked and accepted despite several limitations. Based on this study, fortification of cassava flour with red palm oil has a potential for controlling VAD. In areas of the country where the red palm oil is produced in abundance, enriching cassava flour or other locally produced staples with red palm oil may thus provide a cheap and sustainable method for eliminating VAD. Fortification also improves the flavor hence acceptability of the oil, increases its utilization and improves the energy density of gruels and/or meals prepared from the enriched flour. It is suggested that a detailed study should be undertaken to determine the stability and keeping quality of the red palm oil enriched cassava flour under various conditions to enable a wider distribution of the product in the country.     

(+)-Catechin in human plasma after ingestion of a single serving of reconstituted red wine

BACKGROUND: Red wine consumption may decrease the risk of coronary heart disease through the actions of its constituent flavonoids. (+)-Catechin is an abundant flavonoid in red wine. OBJECTIVE: The objective was to determine changes in plasma (+)-catechin concentrations after ingestion of a single, moderate serving of dealcoholized red wine reconstituted with either water (DRW) or water and alcohol (ARW). DESIGN: Nine subjects (5 men, 4 women) ingested, in random order, 120 mL DRW on one day and 120 mL ARW on another day. Both the DRW and ARW contained 35 mg (121 micromol) free (+)-catechin. Blood samples were collected at 0, 0.5, 1, 2, 3, 4, and 8 h. Plasma was analyzed by gas chromatography-mass spectrometry for (+)-catechin after enzymatic release of sulfate and glucuronide conjugates. RESULTS: Calcium ions were needed to effectively hydrolyze (+)-catechin conjugates in plasma containing EDTA. Neither the ARW or DRW nor sex affected the area under the curve at 8 h, the maximum concentration (c(max)), or the time it took for plasma total (+)-catechin to reach maximum concentration (t(max)). Pooled mean (+/-SEM) values for the ARW and DRW were as follows: area under the curve, 306.1 +/- 29.5 nmol*h/L; c(max), 76.7 +/- 7.5 nmol/L; and t(max), 1.44 +/- 0.13 h. The half-life of (+)-catechin in plasma was significantly less (P = 0.038) after ingestion of the ARW (3.17 h) than after ingestion of the DRW (4.08 h). CONCLUSIONS: Increases in plasma total (+)-catechin concentrations were not significantly different after single moderate servings of either the ARW or DRW. Alcohol in the ARW hastened the elimination of (+)-catechin from the plasma compartment. (+)-Catechin elimination may represent excretion or conversion to methylated derivatives.     

Aleurone flour is a rich source of bioavailable folate in humans.

With the use of novel milling technology, it has become commercially viable to isolate the aleurone layer of cells from wheat grain and to prepare a novel flour from this fraction that has a natural folate concentration of approximately 500 microgram/100 g. The aim of this study was to determine the relative bioavailability of natural folate from aleurone flour when ingested as a cereal. Using a series of randomized, short-term intervention trials with a cross-over involving eight men and eight women aged between 29 and 50 y, we compared the increment of plasma folate following ingestion of 1) 100 g wheat bran cereal (low folate control), 2) 100 g aleurone cereal, and 3) a tablet containing 500 microgram folic acid taken together with 100 g wheat bran cereal (high folate control). Folate absorption was measured by estimating the area under the plasma folate concentration versus time curve. The extent of increase in plasma folate over the 7-hour period following ingestion of aleurone cereal was more than fourfold greater than that observed following the wheat bran cereal (P < 0.0001) and not different from that observed following the 500 microgram folic acid tablet taken with wheat bran cereal. Differences were significant when data for males and females were analyzed separately (P < 0.001). This study has shown that cereal made from wheat aleurone flour is a good source of bioavailable, natural folate.     

Effects of chronic betaine ingestion on methionine-loading induced plasma homocysteine elevation in rats

The effects of chronic betaine ingestion were investigated in rats. Rats were fed an experimental diet containing 5% betaine for 4 wk and methionine was intravenously administered. The elevations of plasma homocysteine were assessed by comparing the increments to the initial measured value and the positive incremental area under the plasma homocysteine concentration curve over the 240-min post-methionine-loading period (deltaAUC0-240). In the betaine-ingesting rats, deltaAUC0-240 was significantly lower than in the control group (48% of the control), and the increments of plasma homocysteine were also lower compared with the control, especially 15-30 min after methionine loading. Choline, a precursor of betaine, did not alter the plasma homocysteine elevation. In a definite period immediately after methionine loading, carnitine, a methyl-group-rich amino acid, induced a significant increase of plasma homocysteine, compared to the control. Moreover, plasma homocysteine concentration was significantly decreased by 4 wk of betaine ingestion. Betaine enhanced liver BHMT activity whereas choline and carnitine did not show any effects on BHMT activity. These results suggest that betaine contributes to both the decrease in the plasma homocysteine concentration and the suppression of plasma homocysteine elevation through the activation of liver BHMT.     

Small intestinal goblet cell proliferation induced by ingestion of soluble and insoluble dietary fiber is characterized by an increase in sialylated mucins in rats

The study aimed to examine the effects of insoluble and soluble fibers on mucin sialylation and sulfation in the small intestine. First, diets containing soluble [konjac mannan (KM), psyllium, or guar gum; 50 g/kg) or insoluble (polystyrene foam, wheat bran, or cornhusk; 80 g/kg) fiber were fed to rats for 13 d. The fiber-fed groups had more goblet cells in the ileum than the fiber-free control group. High-iron diamine/alcian blue staining showed more sialylated mucin-producing cells in the fiber-fed groups than in the control, whereas sulfated mucin-producing cells were fewer (insoluble fibers) or unchanged (soluble fibers). Second, feeding KM (50 g/kg) and beet fiber (BF) (80 g/kg) diets for 7 d yielded a higher ileum Siat4C expression than the control, but Gal3ST2 and Gal3ST4 expression was comparable. Luminal mucin content correlated with sialic acid (r = 0.96; P < 0.001) or sulfate (r = 0.62; P < 0.01), but the slope of the sialic acid-derived equation was greater than that of the sulfate-derived equation, indicating a preferred increase in sialylated mucins. Third, rats were fed the control diet for 10 d while receiving antibiotic treatment. Analysis of the luminal mucin showed that sialylated mucins were more vulnerable to bacterial degradation than sulfated mucins. Finally, a study of bromo-deoxyuridine incorporation in rats fed a BF diet indicated that goblet cell proliferation accompanied by increased sialylated mucin appeared to be related to accelerated ileal epithelial cell migration. We conclude that intestinal goblet cell responses to insoluble and soluble fibers are characterized by increases in sialylated mucin production.     

面粉强化的国际经验及我国面粉强化的推动

面粉强化是国际社会广泛应用的改善营养的方法。我国是面粉生产和消费大国 ,强化面粉对我国的营养改善也将产生重要作用。本文介绍了一些国家面粉强化的经验和营养改善效果。对我国面粉消费和生产企业状况进行论述 ,并介绍了我国面粉强化工作现状和进展情况。     

Trigonelline is not responsible for the acute increase in plasma homocysteine following ingestion of instant coffee

OBJECTIVE: To determine whether trigonelline contributes to the effect of coffee on homocysteine (Hcy). DESIGN AND INTERVENTIONS: This was a randomised crossover study. Subjects consumed 50 mg trigonelline, 5 g of instant coffee (approximately 50 mg trigonelline) or water, consumed as a single dose in 100 ml, with 1 week between each treatment. Blood samples were drawn fasting and hourly for 8 h. Urine samples were collected pretreatment and every 2 h for 8 h. SETTING: Christchurch Clinical Studies Trust, Christchurch, New Zealand. SUBJECTS: Eight healthy male subjects. RESULTS: Instant coffee raised plasma Hcy concentrations compared with water (P=0.019) and trigonelline (P=0.037). Plasma Hcy concentrations were not different between water and trigonelline treatments (P=0.789). The change in plasma Hcy concentration was higher (mean+/-s.e.) 4 h (0.7+/-0.2 micromol/l, P=0.006), 5 h (0.7+/-0.2 micromol/l, P=0.013) and 7 h (0.7+/-0.2 micromol/l, P=0.024) following coffee consumption. Urinary glycine betaine excretion was increased by coffee but not by trigonelline. CONCLUSION: Ingestion of instant coffee acutely elevated plasma Hcy; however, trigonelline is not responsible for this rise. SPONSORSHIP: Supported by the Health Research Council, the Canterbury Medical Foundation, the Foundation of Research, Science and Technology.     

面粉、面制品中过氧化苯甲酰的测定及还原剂的选择

目的在推荐方法的基础上改进并建立高效液相色谱法测定面粉及面制品中过氧化苯甲酰的方法。方法以乙腈-0.01mol/L醋酸铵溶液为流动相,优化色谱分离条件,选择合适的还原剂碘化钾溶液浓度,并以碘化钾溶液的还原能力做对照,比较五种实验室常用还原剂对过氧化苯甲酰的还原效率及色谱分离情况。结果在选择的分离条件下,以10%碘化钾做还原剂,方法的线性范围为0.01mg～0.15mg,最低检出量为0.8ng,相关系数大于0.9996,平均加标回收率介于92.4%～105.3%之间,相对标准偏差为2.3%～4.3%。10%亚硫酸氢钠、10%硫代硫酸钠、10%亚铁氰化钾均可作为转化反应的还原剂。结论所建立的方法灵敏度高,分离效果好。实验室人员可根据情况选择适当的还原剂。     

Long-term ingestion of guar gum is not toxic in patients with noninsulin-dependent diabetes mellitus

The use of diets rich in unabsorbable carbohydrate ("fiber") has been advocated for the treatment of noninsulin-dependent diabetes mellitus (NIDDM). The soluble viscous fibers such as guar gum are most effective in normalizing carbohydrate intolerance in such patients; particulate fibers such as cellulose have little or no effect. While the latter are known to affect many aspects of nutrition when consumed in great quantity, little is known of the toxicity of guar gum. Eight adults with NIDDM are reported here who consumed at least 30 grams of guar gum for at least 16 weeks without any change in hematologic, hepatic, or renal function. Serologic screening revealed no change in lipid, protein or mineral metabolism, and no change in electrolyte balance. It is concluded that consumption of 30 grams of guar gum per day for prolonged periods is without serious consequences.