Purification, characterization, and pathogenicity of urease produced by Vibrio parahaemolyticus

Little is known about the zinc content of breast milk in developing countries. Zinc content in breast milk was analyzed in 34 mothers of low socio-economic status; 17 were primiparae and 17 multiparae. Women in their 6th to 36th week of lactation provided 3 samples of breast milk at different times within a single day. The mean zinc concentration in breast milk (micrograms/ml) was 1.89 +/- 0.64 with a range from 0.17 to 4.38 micrograms/ ml. Zinc content in the morning, midday and evening samples were 2.1 +/- 0.84, 1.74 +/- 0.53, 1.84 +/- 0.69 respectively. There was significant variation between morning and midday samples (p = 0.038). Maternal age, parity, nutritional status or age of the child did not affect the zinc content of milk in the population studied.     

Surgical procedure for modifying the duodenum in cattle to measure bile flow and the diurnal variation in biliary manganese, iron, copper and zinc excretion

A surgical procedure is described for modifying the duodenum of cattle so that bile can be sampled and its rate of flow measured for long periods. In 12 steers, aged three months to three years and weighing between 50 and 650 kg, bile flow ranged from 2 to 12 ml per minute, the rate of flow increasing with bodyweight. The rate of flow expressed as ml per minute per 100 kg bodyweight decreased as bodyweight increased, the regression equation being in (ml per minute per 10 kg) = 1.65-0.0022 x where x = bodyweight (kg), r = 0.871. The mean concentrations of copper, iron, manganese and zinc in bile were 8.2, 6.2, 17.1 and 3.3 mumol per litre respectively. The concentration of iron was the least variable between the steers. The average total cholate concentration was 100 mmol per litre and total solids ranged from 5.4 to 7.2 per cent. Diurnal patterns in bile flow and trace element excretion were measured in four adult steers during a period of 38.5 hours. Although the rate of excretion of iron, zinc and copper and bile flow varied throughout the period, changes could not be associated with feeding or time of day. The concentration of manganese in bile and its excretion rate varied in a reproducible manner which may be related to feeding activity. The mean output of the four trace elements in bile from the four steers during 24 hours was, copper 37.7 mumol, iron 68.0 mumol, manganese 80.3 mumol and zinc 59.6 mumol.     

Influence of vitamin B6 intake on the content of the vitamin in human milk

The influence of the level of vitamin B6 intake on the content of the vitamin in milk was studied in 19 healthy subjects whose stages of lactation ranged from 3 weeks to 30 months. Total vitamin B6 intakes, including extra-dietary sources of the vitamin, ranged from 1.3 to 12.5 mg per day with six subjects consuming less than the recommended allowance of 2.5 mg per day (RDA, 1974). Subjects consuming less than 2.5 mg of vitamin B6 per day had significantly less vitamin B6/liter milk (129 mug) than groups consuming 2.5 to 5.0 or greater than 5.0 mg per day (239 and 314 mug, respectively). Among subjects consuming greater than 2.5 mg of vitamin per day the stage of lactation did not influence the levels of protein or vitamin B6 in milk. Vitamin B6 intakes two to five times the recommended allowance did not significantly elevate the level of the vitamin in milk compared to values for subjects whose intakes approximated the allowance. The vitamin B6/protein ratio in milk of subjects consuming less than 2.5 mg vitamin B6 per day was 13 mug/g and was significantly lower than that observed for the other two groups (23 and 28 mug/g). Daily and weekly variations of the vitamin B6 and protein content in milk of individuals were small. However, marked diurnal variations in the vitamin B6 content were found in milk of individuals taking daily supplements of the vitamin with peak levels occurring in the afternoon 3 to 5 hr after supplements were taken in the morning.     

A longitudinal study of the protein, nitrogen, and lactose contents of human milk from Swedish well-nourished mothers

The contents of total nitrogen, nonprotein nitrogen, lactose, and individual milk proteins have been determined in human milk from well-nourished Swedish mothers. Breast milk samples from 50 mothers at different stages of lactation (up to 170 days) were collected. Furthermore, three mothers gave samples repeatedly throughout the whole lactation period. The protein content in mature milk was found to be 0.8 to 0.9% by amino acid analysis. The nitrogen content and the contents of the major human milk whey proteins, alpha-lactalbumin and lactoferrin, are very high for the first few days, then decrease rapidly and reach, thereafter, the more slowly declining level of mature milk. Nonprotein nitrogen and the nonspecific milk protein serum albumin are present in constant concentrations throughout lactation. The daily milk volumes were determined and found to be 500 to 600 ml in the very early part and 700 to 800 ml in the later part of the lactation period.     

Effects of iron supplementation and discontinuation on serum copper, zinc, calcium, and magnesium levels in women

The purpose of this study was: 1) to establish the prevalence of depleted iron stores, iron deficiency, and low serum levels for copper, zinc, calcium, and magnesium in a healthy female population; and 2) to examine the effects of iron supplementation and discontinuation on the serum levels of the above minerals. One hundred eleven healthy women between the ages of 18 and 40 yr reported for fasted morning blood sampling for iron, copper, zinc, calcium, and magnesium status. Forty-five subjects were either iron-deficient as defined by a hemoglobin level below 120 g.l-1 (four subjects) or iron deplete as defined by a serum ferritin value below 20 micrograms.l-1 (43 subjects). Two subjects fit both criteria. This subgroup continued with the study and were prescribed a normal therapeutic iron dose (320 mg elemental iron per day, taken as two Slow-Fe tablets.d-1 for a period of 12 wk). The subjects then discontinued the iron supplementation for a further 12 wk. The response of the various blood minerals was monitored at 6-wk intervals. Twenty-five subjects completed the full 24-wk treatment. The main conclusions to be made from this study were that: 1) For this sample population of women, iron depletion was quite common (39%), although low hemoglobin values (< 120 g.l-1) were only seen in 3.6%. No subjects fell below the criteria for low serum copper levels (< 13.3 mumol.l-1) nor low serum magnesium levels (< 0.6 mmol.l-1). Seven subjects (6.5%) fell below the criteria for low serum zinc levels (< 11.5 mumol.l-1) while two subjects (1.8%) were below the criteria for low serum calcium levels (< 2.20 mmol.l-1). 2) Therapeutic oral iron supplementation was successful in raising mean serum ferritin values from 15.9 micrograms.l-1 to 36.5 micrograms.l-1 but was not associated with decrements in serum copper or calcium levels. 3) The treatment did not significantly effect serum zinc and magnesium levels during the supplementation period, but a downward trend continued through the discontinuation phase so that at 18 and 24 wk serum zinc and magnesium levels were significantly lower than baseline. 4) Oral contraceptive use was associated with elevated serum copper and ferritin values and lowered serum magnesium levels.     

Sensitive colorimetric determination of cholesterol in dairy products

Cholesterol can be determined colorimetrically in dairy products at levels of larger than or equal to 10 mug (coefficient of variation = 5.3%) with an o-phthalaldehyde reagent when non-cholesterol lipids are eliminated prior to color development. Absorbance for 2 mg tripalmitin was found to be equivalent to about 20 mug cholesterol. Saponification followed by hexane extraction removed interfering lipids. Using the described procedure, 238 individual raw milk samples were found to contain 144.4+/-37.9 mug cholesterol/ml, while their skim milk portions had 26.5+/-6.4 mug cholesterol/ml (mean +/- standard deviation). The o-phthalaldehyde cholesterol estimates agreed with those obtained by a gas-liquid chromatographic procedure when cheese and ice cream were analyzed by the colorimetric procedure with and without prior fat extraction.     

微波消解-电感耦合等离子体原子发射光谱法测定含碳化铬锌物料中铅铜铁镉铬砷

含碳化铬锌物料中含有铬的碳化物,此类碳化物熔点高、化学稳定性好,普通的酸不能完全溶解,需要在强混合酸和高温条件下才能分解。实验选择硝酸-盐酸-氢氟酸并采用微波消解法溶解样品,既能将试样中难溶的碳化铬完全溶解,又有效避免了高温溶样对易挥发元素砷的损失,并使用电感耦合等离子体原子发射光谱法(ICP-AES)测定铅、铜、铁、镉、铬、砷等元素含量。各元素测定范围为:0.10%≤w(Pb,Cu)≤5.00%;0.10%≤w(Fe)≤10.00%;0.010%≤w(Cd,Cr) ≤3.00%;0.08%≤w(As)≤3.00%。各元素在线性范围内校准曲线的线性相关系数均大于0.999,检出限为0.001~0.018μg/mL。实验方法用于测定5个典型含碳化铬锌物料原料样品铅、铜、铁、镉、铬、砷,结果的相对标准偏差(RSD,n=11)为0.75%~2.0%;按照实验方法测定3个含碳化铬锌物料样品中铅、铜、铁、镉、铬、砷,并采用其他方法(其中铅、铜、铁、镉按照GB 6730.30—2016《铁矿石化学分析方法 二苯基碳酰二肼光度法测定铬量》方法进行碱熔后,采用火焰原子吸收光谱法进行测定;铬按照GB 6730.30—2016《铁矿石化学分析方法 二苯基碳酰二肼光度法测定铬量》测定;砷按照GB/T 8151.7—2012《锌精矿化学分析方法 第7部分:砷量的测定 氢化物发生-原子荧光光谱法》测定)进行比对,结果相吻合。     

Effect of iron, zinc, and copper on lipid peroxidation in liver in vivo

Changes in the levels of lipid peroxides, natural antioxidants (NA), iron, zinc and copper as well as the ability of the lipid substrate to oxidize in animal liver in the presence of iron, zinc and copper have been studied. It has been found that those metals increase the amplitude of natural fluctuations in iron, zinc and copper levels in the liver (by 5-30% in comparison with control). Within the first few hours following administration of iron and copper, the concentration of lipid peroxidation (LPO) products in animal livers increases, while the NA level and lipid oxidizeability decrease, in contrast. Zinc inhibits LPO in the liver within the first few hours following the injection. The changes in the content of NA, lipid oxidizeability and the level of LPO products in animal livers following iron, zinc and copper administration are phase-dependent. Data from regression analysis indicate a direct dependence (kcor = 0.98 at p < or = 0.05) between lipid oxidizeability and NA content in the liver following administration of iron, zinc and copper which, in turn, is suggestive of the lack of disturbances in the system of NA regulation     

电感耦合等离子体原子发射光谱法测定铁矿石中16种元素

准确、快速地测定铁矿中各种杂质元素含量,对铁矿石质量判定具有重要意义。试验采用“酸溶-碱熔回渣”的方法消解样品,先用硝酸、盐酸溶解样品,再过滤,滤渣及滤纸灰化后再用碳酸钠-硼酸混合熔剂熔融,溶液中的总固体溶解量(TDS)为2.5mg/mL。采用基体匹配法绘制校准曲线消除基体效应的影响,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定铝、砷、钙、铬、铜、钾、镁、锰、镍、磷、铅、硅、锡、钛、钒、锌等16种元素。各待测元素校准曲线的线性相关系数均大于0.999;方法检出限为0.00018%~0.034%。实验方法用于2个铁矿石实际样品中铝、砷、钙、铬、铜、钾、镁、锰、镍、磷、铅、硅、锡、钛、钒、锌的测定,结果的相对标准偏差(RSD,n=8)为0.40%~9.8%;按照实验方法测定4个铁矿石标准样品,测定值与认定值相吻合;测定4个铁矿石生产样品中铝、砷、钙、铬、铜、钾、镁、锰、镍、磷、铅、硅、锡、钛、钒、锌,测定值与GB/T 6730系列标准方法测定值相吻合。     

电感耦合等离子体原子发射光谱法测定铁矿石中16种元素

准确、快速地测定铁矿中各种杂质元素含量,对铁矿石质量判定具有重要意义。试验采用“酸溶-碱熔回渣”的方法消解样品,先用硝酸、盐酸溶解样品,再过滤,滤渣及滤纸灰化后再用碳酸钠-硼酸混合熔剂熔融,溶液中的总固体溶解量(TDS)为2.5mg/mL。采用基体匹配法绘制校准曲线消除基体效应的影响,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定铝、砷、钙、铬、铜、钾、镁、锰、镍、磷、铅、硅、锡、钛、钒、锌等16种元素。各待测元素校准曲线的线性相关系数均大于0.999;方法检出限为0.00018%~0.034%。实验方法用于2个铁矿石实际样品中铝、砷、钙、铬、铜、钾、镁、锰、镍、磷、铅、硅、锡、钛、钒、锌的测定,结果的相对标准偏差(RSD,n=8)为0.40%~9.8%;按照实验方法测定4个铁矿石标准样品,测定值与认定值相吻合;测定4个铁矿石生产样品中铝、砷、钙、铬、铜、钾、镁、锰、镍、磷、铅、硅、锡、钛、钒、锌,测定值与GB/T 6730系列标准方法测定值相吻合。     

Factors that influence milk cholesterol and lipid phosphorus: content and distribution

Average cholesterol content of 356 raw milk samples was 152.2 mug/ml and upon centrifugation (3000 X g for 8 min), 16.9% was distributed in the skim milk phase. Lipid phosphorus averaged 19.0 mug/ml and was partitioned 50:50 between cream and skim milk phases. Weight ratios of cholesterol to lipid phosphorus for milk and skim milk were 8.30:1 and 2.94:1. When variation due to milk yield, fat percent, and somatic cell numbers (deoxyribonucleic acid percent reflectance) was accounted for by least squares, cholesterol content and distribution did not differ among breeds (Holstein, Jersey, and Guernsey). Breed differences in lipid phosphorus content of whole milk could not be detected. However, Holsteins had a significantly lower content of lipid phosphorus and a higher weight ratio for skim milk. Milk yield, fat content, and somatic cells affected responses of cholesterol and lipid phosphorus. This supports a multiple origin concept for membrane material in skim milk.     

Open study of a diclofenac sodium prolonged-release in patients suffering from coxarthrosis

Inductively coupled plasma atomic emission spectroscopy (ICP-AES) was used for routine analysis of small samples of human milk. The concentrations of calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), phosphorus (P), and zinc (Zn) were determined in 203 milk samples from postpartum women at different stages of lactation after stepwise digestion in HNO3, HClO4, and H2O2 under heat. Validation of the procedure was achieved using certified reference material of bovine liver (NBS 1577) with mean recoveries of 103.5%. The concentrations of the above elements in milk matrix were comparable with previously reported values. The analytical results from breast milk will provide reference information for mineral studies of Brazilian mothers and breast-fed infants.     

Diamagnetic levitation in the fractionally superconducting bile cholates

Plasma zinc levels were measured in both healthy and diabetic individuals having an age range of 10-93 years. No significant differences in plasma zinc concentrations were found between males and females in either healthy or diabetic individuals. Up to the age of 50 years, the mean plasma zinc of normal individuals remained relatively constant at 70 +/- 32 mug/100 ml (+/- 2 SE) after which the levels decreased. This decreasing pattern was absent in diabetics, whose plasma zinc of 65 +/- 32 mug/100 ml remained constant over the entire age range. For women on oral contraceptive agents, the mean plasma zinc was 59 +/- 18 mug/100 ml, which was significantly lower than that of controls.     

Acute abdomen accompanying hepatic parenchymal changes

Total femur zinc of young rats was used to evaluate the biological availability of zinc in milk and soy protein-based infant formulas. A zinc deficient diet (0.8 mug Zn/g) containing egg white protein was supplemented with graded levels of zinc from zinc sulfate, milk and soy protein-based infant formulas. A plot of total femur zinc (log) after feeding the diet for 3 weeks versus the zinc added to the diet gave a linear relationship over the range of 0, 3, 6, 9 and 12 mug/g added zinc. By using a slope-ratio bioassay model, the relative biological availability of endogenous and added zinc in milk-based formula was estimated to be 0.86 and that of soy-based formula 0.67 (zinc sulphate = 1.00) with corresponding 95% fiducial limits being 0.82 to 0.91 and 0.62 to 0.71. Thus, to provide equivalent amounts of available zinc, the total zinc content of the soy protein-based formula would need to be at least 20% higher than that of the formula containing milk protein.     

X射线荧光光谱法用于粗铜中铜和13种杂质元素的测定

铜冶炼过程的中间产品粗铜中铜质量分数在97.5%以上,常含有砷、锑、铁、铅、锌、锡等杂质元素。使用X射线荧光光谱法(XRF)测定粗铜中铜时,铜元素含量过高导致其X射线荧光强度与铜含量的线性度变差,而且试样的光洁度和密度的差异等因素也导致铜含量测定值偏离真实值。试验首先选取各元素含量均具有梯度的粗铜生产样品,使用多种化学湿法对各元素进行定值。在对XRF测定条件优化的前提下,通过车床加工制样,建立了X射线荧光光谱法(XRF)测定粗铜中13种杂质元素(硫、铁、锑、铋、砷、铅、锌、镍、硒、锡、银、钴、碲)的方法。结合测氧仪提供的氧含量值,通过差减法可计算出粗铜中的铜含量。实验方法用于测定1个粗铜样品中铜和13种杂质元素,测定结果的相对标准偏差(RSD,n=11)小于5%。按照实验方法测定4个铜块中铜和13种杂质元素,测定结果与化学湿法值进行比对,结果表明各杂质元素测定值与湿法测定结果相吻合;而使用差减法计算的铜含量(质量分数均大于97.5%)和化学湿法测定结果差值很小,完全满足生产需要。     

Distribution of a stable isotope of chromium (53Cr) in serum, urine, and breast milk in lactating women

To determine the fate and distribution of chromium during lactation, six lactating women (25-38 y old) were given three doses of the tracer 53Cr (7.55 micromol/d, or 400 microg/d) on days 1, 2, and 3 of the study. Diet records, blood samples taken while subjects were fasting, and 24-h composite milk and urine samples were collected from day 0 to day 6. Fasting blood samples, morning milk samples, and 24-h urine samples were also collected on days 8, 10, 15, 30, 60, and 90. 53Cr and natural and total chromium concentrations in biological fluids were measured with gas chromatography-mass spectrometry and total urinary chromium was measured with atomic-absorption spectrometry. 53Cr was detectable in serum 2 h after dosing and continued to be detected from day 30 to day 60. Changes in total serum chromium concentration in response to the oral dose suggested that chromium concentrations in blood were not tightly regulated. 53Cr was not detected in breast milk and no significant changes in natural chromium concentration in milk were observed in response to the oral doses, suggesting that breast-milk chromium concentrations are independent of intake. The estimated chromium intake of exclusively breast-fed infants was 2.5 nmol/d (0.13 microg/d), below the lower end of the range of estimated safe and adequate daily dietary intakes (10-40 microg/d) for infants 0-6 mo of age. The baseline chromium concentration in urine and the minimum 53Cr absorption in lactating women were comparable with values for nonpregnant, nonlactating subjects. Chromium losses in breast milk do not appear to be compensated for via increased absorption or decreased excretion.     

Lead and cadmium contents in milk, cheese and eggs on the Finnish market

Lead and cadmium contents were determined in nationally representative samples of low-fat milk, cheese and eggs consumed in Finland. Nationally representative samples of milk and cheese were collected from dairies. Egg samples were collected from the major distributors. Samples of imported cheese and egg products collected in surveillance studies were analysed, together with domestic samples. Lead and cadmium were determined by GFAAS after wet digestion in conc. HNO3. In lead determinations of milk and cheese platinum was employed as the matrix modifier and NH4H2PO4 was employed for the lead determinations of eggs and in all cadmium determinations. Mean lead content was 1.7 micrograms/kg in milk, 17 micrograms/kg in Finnish cheese, 17-60 micrograms/kg in imported cheese, 1 microgram/kg in eggs and 6-72 micrograms/kg in imported dry egg products. Although Finnish consumption in milk, cheese and eggs is high the dietary intake of lead and cadmium from these sources is very low compared with the tolerance limits.     

超声辅助-王水提取法在测定土壤中重金属元素的应用

建立了超声辅助王水消解土壤样品的前处理方法,并结合电感耦合等离子体原子发射光谱法(ICP-AES)和电感耦合等离子体质谱法(ICP-MS)对土壤样品中铜、锌、镍、铁、锰、铅、砷、汞、铬、镉等10种元素进行测定。通过试验确定王水用量为5mL、超声水浴温度为80℃、超声提取时间为45min的超声提取条件。在优化的仪器条件下,按照实验方法测得的土壤样品中10种元素的校准曲线线性相关系数为0.9996~0.9999;各元素的检出限为0.0021~0.23mg/kg,各元素的测定下限为0.0070~0.78mg/kg。按照实验方法(超声王水提取-ICP-AES/ICP-MS)测定土壤样品中铜、锌、镍、铁、锰、铅、砷、汞、铬、镉,测定结果的相对标准偏差(RSD,n=6)为0.39%~7.8%;除铁、锰的提取值较小外,其他元素的测定结果与采用国标方法(GB 15618—1995、GB/T 22105.1—2008)得到的测定值基本一致;按照实验方法测定土壤标准物质GBW07404、GBW07406、GBW07407、GBW07427中铜、锌、镍、锰、铅、砷、汞、铬、镉,除了锰由于其在原土中主要以氧化物结合态存在,测定结果偏低以外,其他元素测定值与认定值相吻合。     

火焰原子吸收光谱法快速测定纯镍中铁铜镁锰锌

提出了运用火焰原子吸收光谱法快速测定纯镍中铁铜镁锰锌的含量，介绍了铁铜镁锰锌最佳测定条件及呈良好线性范围的浓度，在测定中对样品中的干扰因素进行了综合考虑。该方法具有很好的灵敏度和重现性，具有方法步骤简单、操作容易、干扰少等特点。测定样品铁铜镁锰锌含量的相对标准偏差均小于1．0％（n=10）。标准加入回收率均在97．0％～99．0％（n=6）范围内。适用于纯镍材料中铁铜镁锰锌的含量控制分析和系统分析。     

Influence of pyridoxine supplementation on vitamin B-6 levels in milk of rats deficient in the vitamin

Levels of vitamin B-6 in milk from pyridoxine deficient dams were used as an indicator of the ability of pyridoxine to protect offspring against the effects of the deficiency. Sprague Dawley rats were fed a basal diet containing 30.0 (control) or 1.2 (deficient) mg pyridoxine-HC1/kg diet from weaning throughout growth, gestation and until 5 days postpartum. At this time, deficient dams were supplemented by a single intraperitoneal injection of 600 mug pyridoxine-HC1, or by adding 30 or 60 mg pyridoxine-HC1/kg to the diet. The vitamin B-6 content in milk form the group supplemented by injection exceeded the control level of 38.8 mug/100 ml milk 30 minutes after the injection, and reached a peak level of 110.7 mug/100 ml at 4 hours with a subsequent decline to 27mug/100 ml at 20 hours. In rats supplemented orally with 30 or 60 mg pyridoxine-HC1/kg diet, the vitamin B-6 level in the milk reached the control value in 24 and 6 hours, respectively. At 120 hours, orally supplemented dams had significantly higher levels of vitamin B-6 in the milk than control animals. Vitamin supplementation of dams by a single injection of pyridoxine-HC1 was sufficient to overcome the pyridoxine deficiency syndrome in the pups, but was not adequate for optimum growth.