Biomedical subjects

C W Weber

Publications and source records attributed to C W Weber.

At least 19 recordsLinked to original sources

PubMed1992

Methylxanthine levels in breast milk of lactating women of different ethnic and socioeconomic classes.

The purpose of this study was to evaluate the dietary caffeine and dimethylxanthine concentrations in breast milk of 40 mothers from different ethnic and socioeconomic backgrounds. Their diets and drug intake were not restricted in any way. Each nursing mother provided a fasting and a combined breast-milk sample each day for 3 consecutive days. No significant differences were found in intake levels of any of the methylxanthines among the groups tested. No significant differences were found among the four groups in breast-milk levels of caffeine, theobromine, or paraxanthine. However, the mean theophylline milk levels were significantly higher on 2 of the 3 days examined in Anglo-American woman compared to Hispanic-American women. Socioeconomic and ethnic variables were also compared among the four groups. The daily amounts of methylxanthines found in the breast milk of this free-living population of mothers do not appear to present clinically significant amounts to the infant.

Adult↗

PubMed1991

Mineral composition of some traditional Mexican teas.

Teas of plant origin traditionally consumed by the Mountain Pima of Chihuahua, Mexico, were analyzed for mineral nutritional content. Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots of Tagetes lucida, T. filifolia, Elytraria imbricata, and Holodiscus dumosus, and from root xylem of Ceanothus depressus and Phaseolus ritensis. Native uses of these teas are also described.

Beverages↗

PubMed1990

HPLC analysis of methylxanthines in human breast milk.

A sensitive and specific high-performance liquid chromatographic (HPLC) procedure is developed for simultaneously quantitating the levels of caffeine, theophylline, theobromine and paraxanthine in breast milk. The method involved the precipitation of proteins present in the milk samples with a 6% v/v perchloric acid solution containing the internal standard, proxyphylline, followed by centrifugation at 12,800 Xg for 10 minutes. The clear supernatant was then chromatographed on a C18 reversed-phase analytical column at ambient temperature using a wavelength of 272 nm. Samples were eluted from the column at a constant flow rate of 1.5 mL/min using a gradient program in which the concentration of methanol in the mobile phase varied from 0 to 16%. The mean recoveries of the methylxanthines averaged over all the concentrations examined were generally excellent and ranged from 96.3 +/- 5.4% for caffeine to 102.3 +/- 8.9% for paraxanthine. The assay precision was very good and the peaks of interest were extremely well resolved. The method is recommended for assessing the total caffeine and dimethylxanthine load to which the nursing infant is exposed in mothers ingesting typical amounts of caffeine.

Caffeine↗

PubMed1990

Trace elements in the hair of healthy and malnourished children.

Pre-school age children from the metropolitan area of Guadalajara, Mexico, consisting of 47 malnourished children were evaluated for mineral status by hair samples and nutritional status by anthropometric measurements and haemoglobin levels. Hair minerals were determined by either atomic absorption spectroscopy or instrumental neutron activation analysis. Malnourished children had significantly lower hair zinc while the iron and copper levels were significantly higher. Hair concentrations of calcium, magnesium, and manganese were not significantly different between healthy and malnourished children. Sixty per cent of the malnourished children's haemoglobin values were either marginal or deficient while 45 per cent of the haematocrits readings were either marginal or deficient. Malnourished children in weight-for-age category were 81 per cent malnourished; by weight-for-height 55 per cent were malnourished and by height-for-age 59 per cent were malnourished. The overall nutritional status of malnourished children can be characterized as mild to severe malnutrition with a chronic stunting of growth. Hair zinc values were a good indicator of nutritional status.

Analysis of Variance↗

PubMed1989

Computerized morphometric quantitation of cellular features in splenocytes from normal and nutrient-restricted mice.

The morphometric analysis of splenocytes reveals quantitative changes in the chromatin and cytoplasm that may be used to distinguish between cells from normally fed animals and cells from subjects fed restricted diets. Analysis of Feulgen-stained and Papanicolaou-stained cells from mice fed normal diets and mice fed either calorie-restricted diets or isocaloric but protein-restricted diets showed an approximately 10% reduction in the nuclear area and in the total optical density (TOD) of stained chromatin in cells from diet-restricted mice. Some changes in chromatin texture features were also observed. Utilization of nuclear area, TOD and one textural feature in a linear discriminant analysis produced a distinct separation of the cells from dietary-restricted mice and the cells from normally fed subjects; this was observed with both Feulgen-stained and Papanicolaou-stained cells. The cellular effect of dietary restriction was more noticeable in the cytoplasm than in the nucleoplasm; Papanicolaou-stained cells from diet-restricted animals showed a 23% reduction in the cytoplasmic TOD and a 10% reduction in the nuclear TOD. This study shows that computerized morphometric analysis may be used in place of or in conjunction with other measurement procedures and chemical tests to quantitate and differentiate cells subjected to different types and levels of nutritional stress.

Animals↗

PubMed1987

Increasing the breaking strength of wounds exposed to preoperative irradiation using vitamin E supplementation.

This study investigated if the prophylactic administration of vitamin E, an antioxidant, normalizes the healing of wounds exposed to preoperative ionizing radiation. Vitamin E was given intraperitoneally to three experimental groups of rats every other day at doses of 10, 20 or 40 International Units (IU) until a total dose of 30, 60 or 120 IU respectively was administered. There were three control groups: non-irradiated control, irradiated, non-supplemented control and irradiated, sesame oil-supplemented control. Two days following the last vitamin E or sesame oil injection 600 Rads of local radiation was delivered to the area of wounding. Two hours following the radiation treatment five centimeter long incisions were made in the area of radiation. There was no difference in the growth of the rats. Radiation exposure significantly reduced the breaking strength (g/5 mm wound) of the wounds compared to non-irradiated controls. With increasing levels of vitamin E there was an increase in the breaking strength of wounds (Y = 360.0 + 0.64 X, SE = 0.27, p less than 0.01). This study provides evidence suggesting that vitamin E may help normalize the breaking strength of wounds that receive preoperative irradiation.

Animals↗

PubMed1984

Lead concentrations of milk, blood, and hair in lactating women.

Lead was measured in the milk of 39 lactating women to determine if the concentration posed a toxicological hazard to nursing infants. Blood and hair of these women were also analyzed for lead to establish possible correlations with milk, and to indicate body burdens. The women were categorized as rural or urban residents so that all mean values of lead could then be correlated with their locations. The mean levels of lead in milk, blood, and hair were 3, 119 ng/ml and 2002 ng/g (ppb), respectively. Lead levels in milk were not considered high enough to pose any threat to the nursing infant. Furthermore, the levels in blood and hair were below values typically cited as average. The three biological parameters did not correlate significantly with each other or with the location of these women. Therefore, it does not appear that the women in this study have high body burdens of lead, or that the nursing infant is at any risk of lead exposure via milk.

Adult↗

PubMed1981

Effect of dietary fiber sources on tissue mineral levels in chicks.

Dietary fiber may influence mineral status of chicks. Wheat bran, corn bran, soy bran, oat hulls, rice bran, and cellulose, were formulated into diets and fed to chicks for 4 weeks. Fiber-added diets contained additional 6% dietary fiber from the fiber sources. Body weights and feed intakes were recorded. Livers and tibias were analyzed for copper, zinc, iron, manganese, and magnesium. The rice bran diet resulted in significantly lowered body weights, feed intakes, and tibia concentrations of zinc, iron, and manganese. The other fiber-added diets did not produce significantly different values for the parameters examined. Dietary analyses showed that the rice bran diet did not have extremely high fiber levels as compared to the other diets. Addition of rice bran contributed the highest amount of phytic acid of all the fiber sources at 1.3% of the diet. It was concluded that when included at 6% of the diet, most fibers did not influence growth or tissue mineral levels. However, the addition of rice bran to the diet reduced body growth and deposition of zinc, iron, and manganese in tibias. It is possible that one fiber source may be beneficial while another is detrimental to nutritional status.

Animals↗

PubMed1979

Longitudinal changes in the mineral content of human milk.

Thirty-eight lactating women, from 1 to 31 months postpartum, provided monthly milk samples for determination of calcium, magnesium, manganese, copper, iron, and zinc. Subjects remained in the study an average of 4 consecutive months, with a maximum participation of 9 months. Subject variation accounted for the majority of variance in the raw data. After statistically controlling subject effect, copper, iron, and zinc levels were shown to be significantly related to duration of lactation. Prediction equations for these three minerals were developed, making it possible to calculate, on an individual basis, the copper, iron, and zinc levels of milk to be produced in future months. Data were also collected to determine possible correlations between breast milk mineral levels and the maternal dietary intake, serum levels, or hair concentration of these same minerals. No significant correlation was found between the milk mineral content and any of the three parameters under study.

Adult↗

PubMed1979

Trace minerals in commercially prepared baby foods.

Five categories of strained baby foods were analyzed for iron, copper, zinc, magnesium, manganese, strontium, and cadmium. Meats, egg yolk, and cerals tended to have the highest concentrations of iron, copper, and zinc. Fruits and vegetables had lower contents of these minerals. Cereals and vegetables were the best sources of magnesium and manganese. Strontium and cadmium levels were consistently low.

Copper↗

PubMed1978

Hair analysis of trace minerals in human subjects as influenced by age, sex, and contraceptive drugs.

Eleven male and 16 female residents of Tucson, Arizona volunteered blood and hair samples and dietary information. Hair and blood samples were analyzed for zinc, copper, magnesium, and iron. Dietary records were calculated for the same. Female subjects had a higher mean hair zinc level than male subjects, but serum zinc was not different for the two groups and mean dietary zinc intake was greater for males. The only difference observed with age was a decrease in hair zinc level over 50 years of age. The taking of oral contraceptives resulted in mean hair copper level numerically decreased while serum copper increased. Mean hair zinc increased with contraceptive use and serum zinc decreased. Mean dietary intakes of copper and zinc were not different between nonpregnant control women and women taking oral contraceptives. For human subjects, mineral concentration of hair, serum, and diet do not correlate well, emphasizing that influencing factors and must be considered in interpreting hair analysis results.

Adolescent↗

PubMed1977

Evaluation of hair analysis for determination of zinc status using rats.

Weanling male and female Sprague-Dawley rats were fed diets of graded levels of dietary zinc from 3 to 68 ppm. The zinc concentrations of hair, bone, and testes reflected the dietary intake by increasing with each increment of dietary zinc. Kidney zinc indicated the state of zinc metabolism by declining on restricted intakes and remaining constant above the requirement level. Plasma and liver zinc concentrations and enzyme activities were not related to dietary intake nor were any significant changes observed with restricted zinc intakes. Hair zinc levels decreased more rapidly with dietary zinc levels below the zinc requirement. Therefore, hair zinc analysis can be used to aid in diagnosis of a deficiency or evaluate dietary intake for the rat but can not be used to assess the state of zinc metabolism.

Animals↗

PubMed1974