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Biomedical subjects

C M Weaver

Publications and source records attributed to C M Weaver.

84 records · Page 5Linked to original sources
PubMed1984

Bioavailability of iron to rats from processed soybean fractions determined by intrinsic and extrinsic labeling techniques.

Intrinsic and extrinsic labeling techniques were used to measure iron bioavailability from soybean fractions (isolated soy protein, defatted flour, soy hulls, insoluble material and whey) by iron-depleted and non-iron-depleted rats. As expected, absorption of iron was higher in the iron-depleted than in the non-iron-depleted rats. In the iron-depleted group, significantly more iron was absorbed from soy whey than from other fractions. No other significant difference in iron absorption associated with iron source was observed. The higher absorption rate of iron from whey by the iron-depleted rats probably was related to a lower quantity of food consumed during the test meal by this group. Intrinsic and extrinsic labeling techniques produced similar assessments of bioavailability of iron.

Animals↗
PubMed1984

Removal of electrolytes from institutionally packaged foods.

Soaking and rinsing resulted in significant (p less than .01) reductions in sodium and potassium concentrations of peeled potatoes and hard-cooked eggs packed in brines containing sodium compounds and packaged for institutional use. In this study, no significant differences (p greater than .01) were found between soaking and rinsing in deionized water and in tap water; however, tap water can vary greatly in sodium and potassium content. Sodium and potassium levels of chopped lettuce dipped in sodium hypochlorite were not significantly (p greater than .01) affected by soaking and rinsing procedures. However, the sodium and potassium levels of the processed lettuce were not high relative to the levels of unprocessed lettuce before soaking and rinsing.

Eggs↗
PubMed1983

Labeling of soybeans with the stable isotope 70Zn for use in human metabolic studies.

Radiozinc (65Zn) was used to assess the efficiency of incorporation of the label into soybean seeds by means of a noncycling hydroponic system. It was found that 21.3 and 27.6% of the applied dose was incorporated into the mature seeds when the tracer was applied during vegetative or flowering stages of growth cycle, respectively. The latter method was adapted to labeling with the stable isotope 70Zn, and quantitative incorporation of this isotope was investigated within and among hydroponic culture pots each containing four plants. It was found that on the average 17.7% +/- 3.0% of the applied dose was recovered in the mature seeds harvested from each pot. The mass isotope enrichment ratio for 70Zn: 68Zn in these seeds was 2.93 +/- 0.38 (mean +/- SD) compared with the natural ratio of 0.0343, indicating a high degree of stable isotope enrichment. Results of soybean fractionation studies showed that the enrichment was somewhat higher in the defatted meal fraction as compared with the full-fat, the hull, and the whole seed, indicating somewhat preferential translocation of the applied stable isotope in the protein. Despite this small but observable difference, all fractions were highly enriched with 70Zn. The data from this study indicated that noncycling hydroponic culture may be effectively employed to intrinsically label soybeans with the stable isotopes of zinc for use in human feeding trials dealing with the issues of zinc availability. A 100-g portion of such labeled seeds provided 38-43 g protein and 490-620 micrograms 70Zn in various processed products for use in human feeding studies.

Humans↗
PubMed1983

Bioavailability of zinc from defatted soy flour, soy hulls and whole eggs as determined by intrinsic and extrinsic labeling techniques.

Bioavailability of zinc from diets prepared from intrinsically and extrinsically labeled autoclaved, defatted soy flour and scrambled, freeze-dried egg was investigated in male rats marginally depleted in zinc. In one study, retention of zinc from intrinsically labeled soybean flour (73%) was significantly less than from 65ZnCl2 extrinsically added to a soy flour-based diet (80%). Zinc from intrinsically labeled soybean hulls and from soy flour diets containing 10% soybean hulls extrinsically labeled with 65ZnCl2 was as available as the zinc from the extrinsically labeled soy flour diet. In a second study, extrinsic and intrinsic labeling techniques gave a similar assessment of bioavailability of zinc from egg- and soy flour-based diets when extrinsic labeling was accomplished by thoroughly mixing 65ZnCl2 with the protein source prior to incorporation into the diet. Absorption of 65Zn was greater from egg diets than from soy flour diets and of intermediate value from mixed soy flour and egg (50:50, wt/wt) diets regardless of which protein source was labeled, indicating that the zinc entered a common pool.

Animals↗
PubMed1980

Polybrominated biphenyl congener levels and distribution patterns in raw and cooked beef.

The retention and distribution of eight polybrominated biphenyl (PBB) congeners were studied by roasting beef sirloin tip samples to an internal temperature of 65 degrees C, braising and broiling adductor and semimembranosus steaks to an internal temperature of 77 degrees C, broiling ground round and hamburger patties 77 degrees C, and comparing cooked values with those in the raw. Rounds were obtained from four Holstein cows with known PBB contamination. Significant reductions in PBBs occurred with cooking of all cuts. Roasting sirloin tips reduced the PBBs by 45.7%. Broiling reduced PBBs as follows: Adductor steaks (53.2%), semimembranosus steaks (71.2%), ground beef patties (32.3%) and hamburger patties (31.5%). Braising reduced PBBs in the adductor steaks by 37.2% and in the semimembranosus steaks by 34.9%. The distribution of PBB congeners was also affected by cooking in all cuts except hamburger. The proportion of 2,4,5,2',4',5'-hexabromobiphenyl decreased upon cooking but the change in the proportion of 2,3,4,5,2',4',5'-hepatbromobiphenyl varied with the cut used. Both of these isomers are known to be phenobarbital type inducers. The proportion of 2,4,5,3',4'5'-hexabromobiphenyl, which both a 3-methylcholanthrene and phenobarbital type inducer, increased in the roasted sirloin tip surface and broiled ground round patties.

Animals↗
PubMed1972

Isotope encephalography in the management of acute herpesvirus encephalitis.

Two patients with Herpesvirus hominis (herpes simplex) encephalitis were investigated by serial isotope encephalograms using technetium-99m pertechnetate. In the first case the diagnosis was made by brain biopsy, and by successful tissue culture, and was confirmed by a significant rise in antibody titre, but in the second the laboratory evidence was exclusively serological. Necrotizing encephalitis was presumed in both cases because the illness was grave and focal signs developed in conjunction with radiological and electroencephalographic evidence of circumscribed lesions of the hemisphere. The emergence of new lesions in the brain scan at a time of clinical remission was found to be a warning of impending relapse. Such lesions had to be distinguished from areas of increasing uptake of isotope due only to local change in vascular permeability. Decay of EEG activity together with clinical signs of focal abnormality over an area of isotope concentration indicated a necrotizing lesion. Cytosine arabinoside (cytarabine), an alternative to idoxuridine as an antiviral drug, was used in both cases. A third patient, suspected in life of having a degenerative encephalopathy, was found at necropsy to have necrotizing encephalitis. Herpes infection though probable was not confirmed. The most severe lesions were in the frontal and temporal lobes, which had shown increased uptake of technetium in the encephalogram performed six weeks before her death.

Cerebral Angiography↗
PubMedDate not supplied

Dairy calcium is related to changes in body composition during a two-year exercise intervention in young women.

OBJECTIVE: Relationships between micronutrients and dairy product intake and changes in body weight and composition over two years were investigated. DESIGN: Two year prospective non-concurrent analysis of the effect of calcium intake on changes in body composition during a two year exercise intervention. SUBJECTS: 54 normal weight young women, 18 to 31 years of age. MEASURES OF OUTCOME: Mean intakes of nutrients of interest were determined from three-day diet records completed at baseline and every six months for two years. The change in total body weight and body composition (assessed by dual x-ray absorptiometry) from baseline to two years was also determined. RESULTS: Total calcium/kilocalories and vitamin A together predicted (negatively and positively, respectively) changes in body weight (R2 = 0.19) and body fat (R2 = 0.27). Further, there was an interaction of calcium and energy intake in predicting changes in body weight, such that, only at lower energy intakes, calcium intake (not adjusted for energy) predicted changes in body weight. CONCLUSIONS: Regardless of exercise group assignment, calcium adjusted for energy intake had a negative relationship and vitamin A intake a positive relationship with two year changes in total body weight and body fat in young women aged 18 to 31 years. Thus, subjects with high calcium intake, corrected by total energy intake, and lower vitamin A intake gained less weight and body fat over two years in this randomized exercise intervention trial.

Absorptiometry, Photon↗
PubMedDate not supplied

Potential application of LASER/microbe bioassay technology for determining water-soluble vitamins in foods.

A microbiological technique was developed for quantitating niacin by determining microbial growth rates in response to the amount of vitamin available. Unlike the current official AOAC method, the new procedure for niacin measured the growth rates during the early exponential growth phase rather than during the stationary phase. Lactobacillus plantarum was used to determine niacin to a lower limit of 100 pg/mL. The assay time was approximately 6 h, compared with 16-24 h for the current AOAC method. The extent of microbial growth was determined by differential light scattering of a LASER beam. Multiple photodetectors were integrated with a computer system to collect and analyze the data. The use of differential light scattering to determine 8 water-soluble vitamins under stationary phase conditions demonstrated the potential application of the new technology for microorganisms and foods.

Biological Assay↗