Factors involved in the persistence of overweight among children enrolled in the supplemental food program for women, infants, and children.

OBJECTIVE: To investigate differences between children ages 2 and 5 years enrolled in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) in Texas whose overweight persisted and those whose overweight resolved. METHODS: The study involved administration of a survey to a randomly selected stratified sample of parents and guardians of WIC children residing in the 11 public health regions in Texas. Subjects volunteered to complete the survey during a scheduled WIC appointment. A total of 445 surveys were completed, 206 by parents/guardians of children classified as having persistent overweight, and 239 by those with children classified as having non-persistent overweight. RESULTS AND CONCLUSIONS: A higher percentage of children in the non-persistent group were male, younger, white, consumed more dairy products, had a mother living in the household, and a family member who participated in physical activity with the child. A higher percentage of parents of children in the persistent group reported that they had been told their child was overweight and received information about overweight in children from the WIC staff. A higher percentage also felt their child was overweight, that their child's weight could be improved, that their child's weight did not improve in the last year and were concerned about their child's weight. This study identified several variables associated with overweight persistence. WIC personnel and other public health educators can utilize these findings to identify overweight children who are at higher risk for non-improvement and to plan more effective intervention strategies for the population studied.

Effects of conventional and grass-feeding systems on the nutrient composition of beef.

The objectives of this study were to determine the nutrient composition of grass-fed beef in the United States for inclusion in the USDA National Nutrient Database for Standard Reference, and to compare the fatty acid composition of grass-fed and conventionally fed (control) beef. Ground beef (GB) and strip steaks (SS) were collected on 3 separate occasions from 15 grass-fed beef producers that represented 13 different states, whereas control beef samples were collected from 3 regions (Ohio, South Dakota, and Texas) of the United States on 3 separate occasions. Concentrations of minerals, choline, vitamin B(12), and thiamine were determined for grass-fed beef samples. Grass-fed GB samples had less Mg, P, and K (P < 0.05), and more Na, Zn, and vitamin B(12) (P < 0.05) than SS samples. Fat color, marbling, and pH were assessed for grass-fed and control SS. Subjective evaluation of the SS indicated that grass-fed beef had fat that was more yellow in color than control beef. Percentages of total fat, total cholesterol, and fatty acids along with trans fatty acids and CLA were determined for grass-fed and control SS and GB. Grass-fed SS had less total fat than control SS (P = 0.001), but both grass-fed and control SS were considered lean, because their total fat content was 4.3% or less. For both GB and SS, grass-fed beef had significantly less (P = 0.001 and P = 0.023, respectively) content of MUFA and a greater content of SFA, n-3 fatty acids, CLA, and trans-vaccenic acid than did the control samples. Concentrations of PUFA, trans fatty acids, n-6 fatty acids, and cholesterol did not differ between grass-fed and control ground beef. Trans-vaccenic acid (trans-11 18:1) made up the greatest concentration of the total trans fats in grass-fed beef, whereas CLA accounted for approximately 15% of the total trans fats. Although the fatty acid composition of grass-fed and conventionally fed beef was different, conclusions on the possible effects of these differences on human health cannot be made without further investigation.

A comparison between improvers and non-improvers among children with anemia enrolled in the WIC program.

OBJECTIVES: To investigate differences between children ages one to five enrolled in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) in the state of Texas whose anemia status improved and those whose anemia status did not improve. METHODS: The study involved administration of a survey to a randomly selected stratified sample of parents and guardians of WIC children residing in the eleven public health regions in Texas. Subjects volunteered to complete the survey during a scheduled WIC appointment. A total of 459 usable surveys were completed. Fifty-one percent of the surveys were completed by parents/guardians of children classified as anemia improvers and 49% were completed by parents/guardians of children classified as anemia non-improvers. RESULTS AND CONCLUSIONS: A majority of the respondents were the child's parent (97%). Most of the children were Hispanic/Latino (77%). More non-improvers than improvers were of young age (p < 0.01), had a parent/guardian who was 18-30 years of age (p < 0.01), lived in a household with four or more other children (p = 0.05) and were from households with a very low income (p = 0.03). Compared to improvers, non-improvers ate fewer snacks (p = 0.01) and a greater percentage never consumed dried fruits (p < 0.01). Knowledge level of the parents/guardians was similar for the two groups. A high percentage of parents/guardians of non-improvers incorrectly believed that their child's condition had improved. WIC staff and other public health educators can utilize these findings to identify those children with anemia who are at higher risk for non-improvement.

Dimethyldiselenide and methylseleninic acid generate superoxide in an in vitro chemiluminescence assay in the presence of glutathione: implications for the anticarcinogenic activity of L-selenomethionine and L-Se-methylselenocysteine.

The reduction of cancer incidence by dietary supplementation with L-selenomethionine, L-Se-methylselenocysteine, and other methylated selenium compounds and metabolites is believed to be due to the metabolic generation of the monomethylated selenium species methylselenol. Dimethyldiselenide and methylseleninic acid were reduced by glutathione in an in vitro chemiluminescent assay in the presence of lucigenin for the detection of superoxide (O2-.). The methylselenol produced on reduction of dimethyldiselenide and methylseleninic acid was found to be highly catalytic, continuously generating a steady state of O2-. The O2-. detected by the chemiluminescence generated by methylselenol was fully quenched by superoxide dismutase, causing a complete cessation of chemiluminescence. In contrast, dimethyldisulfide in the presence of glutathione was not catalytic to any measurable extent and did not generate any superoxide. These in vitro results suggest that methylselenol catalysis is possible in vivo, and if metabolism generates sufficient concentrations of methlylselenol from L-selenomethionine or L-Se-methylselenocysteine in vivo, it could change the redox status of cells and oxidatively induce cellular apoptosis.

The effects of dietary selenomethionine on polyamines and azoxymethane-induced aberrant crypts.

We evaluated the effects of dietary selenomethionine supplementation on colonic polyamine levels and the ability of L-selenomethionine supplementation to modulate the carcinogenic activity of azoxymethane (AOM) in the rat colon. Four-week-old male F344 rats were treated with 15 mg/kg body weight of AOM once a week for 2 weeks. Dietary selenomethionine at a concentration of either 1 or 2 ppm was administered in AIN-76A rodent diet to AOM-treated animals for 16 weeks. Aberrant crypt foci (ACF), precursor lesions of colon cancer, were investigated after the 16 week treatment course. Selenomethionine given in the diet at 2 ppm markedly reduced the number of aberrant crypt foci. The multiplicity of ACFs (i.e. the number of aberrant crypts/focus) and the percentage of microadenomas were also affected by selenomethionine in a dose dependent manner. However, evaluation of the colonic tissue polyamine levels between control and treated groups showed no significant difference. These results demonstrate that selenomethionine can modulate the development of AOM-induced premalignant lesions through a polyamine-independent mechanism.

Depletion and repletion of biotinyl enzymes in liver of biotin-deficient rats: evidence of a biotin storage system.

The quantities of biotinyl proteins in liver of young rats were compared with age-matched controls at intervals during depletion and repletion of biotin. Growth rate and the concentrations of biotinyl proteins previously proposed as mitochondrial storage forms of acetyl CoA carboxylase rapidly decreased in response to biotin deprivation, whereas neither the concentration nor activity of cytosolic acetyl CoA carboxylase was affected. Concentrations of carboxylases active within mitochondria (pyruvate carboxylase, propionyl CoA carboxylase and 3-methyl crotonyl CoA carboxylase) decreased only after d 28. When biotin was injected into biotin-deficient rats, concentrations of the carboxylases active within mitochondria were restored to control levels within 3 h, whereas the concentrations of putative mitochondrial storage forms of acetyl CoA carboxylase reached normal levels only after 9 h, indicating that the injected biotin was preferentially used for the synthesis of the carboxylases active within mitochondria rather than acetyl CoA carboxylase. Mitochondrial acetyl CoA carboxylase may serve as a reservoir to maintain a normal concentration of cytosolic acetyl CoA carboxylase in liver of rats deprived of biotin and provide biotin, indirectly, to maintain essentially normal concentrations of the biotinyl enzymes active within mitochondria for several weeks after rats were fed a biotin-deficient diet.

Exon 16 del: a novel form of human neutral endopeptidase (CALLA).

The enzyme neutral metalloendopeptidase (E.C. 3.4.24.11), also known as the common acute lymphocytic leukemia antigen, neutral endopeptidase, or enkephalinase, functions as an inactivator of a wide variety of signaling oligopeptides such as substance P, neurokinin A, enkephalins, endothelin, atrial natriuretic factor, and formyl chemotactic peptides. A cDNA clone isolated from a human lung library encodes a fragment of neutral metalloendopeptidase containing an internal 81 base pair deletion when compared with the human placental cDNA for this enzyme. Comparison of the deleted cDNA sequence with the intron-exon structure recently determined as the common acute lymphocytic leukemia antigen reveals that the 81 base pairs corresponds precisely with exon 16. RNA analysis using splice junction oligonucleotides indicates that the 16 del form constitutes a minor but significant fraction of the RNA species present in human lung. Expression of constructs containing "wild type" and "exon 16 del" neutral endopeptidases in COS-7 cells reveals that deletion of this 27 amino acid segment reduces enzymatic activity toward the synthetic substrate glutaryl-alanyl-alanyl-phenyl-alanyl-4-methoxy-2-naphthylamide to barely detectable levels.

Analysis of the importance of arginine 102 in neutral endopeptidase (enkephalinase) catalysis.

Neutral endopeptidase 24.11 contains an active site arginine believed to function in substrate binding. This arginine is thought to form an ionic interaction with the COOH-terminal carboxylate of NEP substrates. The functionality of arginine 102 has been investigated by using site-directed mutagenesis to produce mutants in which this residue was converted to a lysine, glycine, glutamine, or glutamate. All of the mutants exhibited essentially full activity as determined with a synthetic peptide amide, glutaryl-Ala-Ala-Phe-4-methoxy-2-naphthylamide. In contrast, activity was detected only with the wild-type enzyme and the lysine mutant using a synthetic substrate containing a free COOH-terminal carboxylate, dansyl-Gly-Trp-Gly. Inhibition studies with the physiologically active peptide substrates substance P, endothelin, and angiotensin I, as well as substance P free acid, [D-Ala2,Leu5]enkephalin, and [D-Ala2,Leu5]enkephalinamide indicated a lack of importance of arginine 102 in substrate binding. With [D-Ala2,Met5]enkephalin and the chemotactic peptide, N-formyl-Met-Leu-Phe, a significant decrease in affinity is observed with the arginine 102 mutants. These results suggest that the contribution of arginine 102 to substrate binding is dependent upon the strength of other subsite interactions. Examination of dipeptides as inhibitors indicates that the nature and orientation of the P'2 residue is important in determining the strength of the interaction of arginine 102 with its substrates.

Mutational analysis reveals only one catalytic histidine in neutral endopeptidase ("enkephalinase").

Aside from serving as zinc ligands, kinetic data has implicated one or more additional histidines as catalytic residues in neutral endopeptidase ("enkephalinase") action. One of these histidines has previously been identified as histidine 704 (Bateman et al., J. Biol. Chem., 265:8365-8368, 1990). In order to determine whether a second histidine is involved in catalysis each of these residues not previously changed have been converted to glutamine by site directed mutagenesis. The resultant recombinant enzymes possess full catalytic activity indicating that histidine 704 is the only catalytic histidine in the enzyme.

Dietary fiber sources lower blood cholesterol in C57BL/6 mice.

Five sources of dietary fiber were compared for their effect on blood and liver cholesterol. The effects of soybean fiber, rice bran (full fat), oat bran, barley bran and mixed bran on total blood cholesterol concentrations and liver cholesterol concentrations were measured in beef-fed C57BL/6 male mice. Each diet contained cooked beef, beef tallow, corn starch and 7% dietary fiber from one of the five fiber sources. A control group consumed a fiber-free diet. Dietary cholesterol was provided by the beef and beef tallow only. The experimental diets were fed for 3 wk; blood and liver were collected when the mice were 18 wk old. The liver cholesterol concentration in the rice bran-fed group was the lowest of the six diet groups and was significantly different than concentrations in the oat bran-fed group and the barley bran-fed group (P less than 0.05). The oat bran, mixed bran, and barley bran did not significantly lower blood cholesterol in the mice. Both the soybean fiber and rice bran diet groups had significantly lower total blood cholesterol than did the fiber-free controls (P less than 0.05). The soybean fiber group also had significantly lower blood cholesterol than the mixed-bran group.

Mitochondrial acetyl-CoA carboxylase. Time course of mobilization/activation in liver of refed rats.

Fasted (48 h) rats were killed at 0, 2, 4, 6, 8, 12, 16, 20 and 24 h after they were refed on a high-carbohydrate diet. An increase in the maximal activity and quantity of cystolic acetyl-CoA carboxylase was found in liver of refed rats after a lag time of about 8 h. The increased quantity of cytosolic enzyme was attributable primarily to mobilization of mitochondrial storage forms and not to substantial increase in the rate of synthesis of acetyl-CoA carboxylase.

Bovine milk-fat-globule membrane contains an enzymically inactive form of acetyl-CoA carboxylase.

Enzymically inactive acetyl-CoA carboxylase [acetyl-CoA:carbon-dioxide ligase (ADP-forming), EC 6.4.1.2] was found as a component of bovine milk-fat-globule membrane (MFGM). Acetyl-CoA carboxylase was present in MFGM at a higher concentration than in cytosolic or mitochondrial fractions of bovine mammary tissue, which makes it unlikely that its presence was due to simple contamination by these subcellular constituents.

Identification of intermediate filament keratin proteins in parakeratinized odontogenic keratocysts. A preliminary study.

The keratin proteins were extracted from the epithelial lining of three odontogenic keratocyst specimens. Two of the specimens were from a patient with nevoid basal cell carcinoma syndrome; the third was a solitary lesion. Seven keratin proteins with molecular weights of 46, 48, 50, 52, 54, 58, and 59 kilodaltons were identified by SDS-polyacrylamide gel electrophoresis and immunoblotting with antikeratin antiserum. The reproducibility of the pattern of molecular markers implies a series of genetic events coincident with the characteristic pattern of epithelial differentiation.