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Biomedical subjects

L T Miller

Publications and source records attributed to L T Miller.

At least 19 recordsLinked to original sources

Developmental changes in speed of information processing in young children.

This study investigated developmental increases in processing speed in young children, relative to adults, with only nonverbal stimuli. R. Kail's (1991) model of the rate of change in processing speed from childhood to adulthood was evaluated. Processing speed was measured in 34 children at 4 years, 37 at 5 years, and 38 at 6 years and in 43 adults, with a battery of 8 computer-administered tests. Results showed clear age-related increases in processing speed that cannot be attributed to increased accuracy and error rate monitoring. Kail's model adequately accounted for the observed rate of developmental change in processing speed; however, the parameter estimates of R. Kail and Y. Park (1992) provided more accurate predictions than did the meta-analytically derived estimates of Kail (1991). Findings support the global developmental trend hypothesis and suggest that this trend extends beyond the range of verbal skills evaluated in previous research.

Adult

Changes in vitamin B-6 status indicators of women fed a constant protein diet with varying levels of vitamin B-6.

Changes in vitamin B-6 status indicators were evaluated in vitamin B-6-replete subjects. Ten young women consumed diets providing 85 g protein/d and 1.03, 1.33, 1.73, and 2.39 mg vitamin B-6/d for 12 or 15 d during four successive diet periods; in a second study, six women were fed diets providing 85 g protein/d and 0.84, 1.14, and 2.34 mg vitamin B-6/d for 10 or 12 d during three successive diet periods. Vitamin B-6 status indicators showing significant differences among intakes included urinary excretion of 4-pyridoxic acid and total vitamin B-6, pyridoxal 5'-phosphate and total vitamin B-6 in plasma, and xanthurenic acid excretion after a 2-g L-tryptophan load. Significant correlations were found between vitamin B-6 intake and 4-pyridoxic acid, total vitamin B-6, plasma pyridoxal 5'-phosphate, plasma total vitamin B-6, erythrocyte alanine aminotransferase percentage stimulation and postload excretion of xanthurenic acid and volatile amines (kynurenine plus acetylkynurenine). Depending on the indicator, between 20% and 70% of the subjects had inadequate values for 4-pyridoxic acid, total vitamin B-6, plasma pyridoxal 5'-phosphate, and erythrocyte alanine aminotransferase percentage stimulation at a vitamin B-6 intake of 1.33 mg/d (0.016 mg vitamin B-6/g protein). A ratio of dietary vitamin B-6 to protein > 0.016 mg/g is required for adequate vitamin B-6 status in women.

Adult

Experimental evaluation of "The Images Within": an alcohol education and prevention program.

A program titled "The Images Within" was implemented and evaluated in three sites on the east coast of the United States. This school curriculum uses art work developed by children of alcoholics to stimulate classroom discussions of the problems of parental alcohol abuse. The evaluation with 278 experimental and 310 control students indicated increased knowledge about the effects of alcohol and improved skills in coping with alcohol problems and help seeking behavior. Process data indicated that related programs were initiated, students were stimulated by the program and teachers were positive in their perceptions of the program. Schools implementing this program need to have developed referral networks to handle the individual concerns that are expressed as a result of participation in "The Images Within."

Adaptation, Psychological

Vitamin B-6 status indicators decrease in women consuming a diet high in pyridoxine glucoside.

Previous research has shown that the pyridoxine glucoside (PNG) form of vitamin B-6 has a reduced bioavailability compared with pyridoxine, but its effect on vitamin B-6 status has not been assessed. Following an 8-d adjustment period, nine women consumed diets containing a high or low amount of PNG for 18 d each, in a crossover design. The high and low PNG diets provided 1.52 mg/d (8.98 micromol/d) and 1.44 mg/d (8.57 micromol/d) of vitamin B-6, of which 27% and 9% was PNG, respectively. The dietary vitamin B-6 to protein ratio of both diets was 0.017 mg/g. Urinary excretions of 4-pyridoxic acid and total vitamin B-6 were significantly lower (P < 0.05) during the high PNG diet period than when the low PNG diet was consumed. Urinary PNG excretion was equal to about 9% of the total PNG intake during both periods. Plasma total vitamin B-6 (P < 0.01) and red blood cell pyridoxal 5'-phosphate (PLP) (P < 0.05) were significantly lower when the high PNG diet was consumed than during the low PNG diet period. Fecal total vitamin B-6 excretion was significantly higher (P < 0.001) when the high PNG diet was consumed. Women consuming a diet containing a higher percentage of the total vitamin B-6 intake as PNG exhibited a decrease in vitamin B-6 status indicators, consistent with the reduced bioavailability of PNG demonstrated in other studies, equal to a loss of 15-18% of the total vitamin B-6 intake. During the determination of Recommended Dietary Allowances, the reduced bioavailability of PNG and its presence in higher amounts in some diets should be considered.

Adult

Vitamin B-6 status of women with a constant intake of vitamin B-6 changes with three levels of dietary protein.

To determine the effect of varying levels of dietary protein with a constant intake of vitamin B-6 (B-6) on B-6 status, nine women were fed diets providing daily intakes of 1.25 mg B-6 and 0.5, 1.0 and 2.0 g protein/kg body weight. After an 8-d adjustment period, the women consumed each level of dietary protein for 14 d in a Latin-square design. Several direct and indirect B-6 status indicators were measured in blood and urine. Significant differences among protein levels were found for urinary 4-pyridoxic acid (4-PA) excretion (P < 0.01), plasma pyridoxal 5'-phosphate (PLP) concentration (P < 0.05), and urinary excretion of volatile amines (VA, kynurenine plus acetylkynurenine) after a 2-g L-tryptophan load (P < 0.05). Nitrogen intake was significantly negatively correlated with urinary 4-PA excretion (r = -0.619, P < 0.001) and plasma PLP concentration (r = -0.549, P < 0.01), and positively correlated with erythrocyte alanine aminotransferase percentage stimulation (r = 0.418, P < 0.05) and urinary post-tryptophan load excretion of xanthurenic acid (r = 0.535, P < 0.05), kynurenic acid (r = 0.563, P < 0.05) and VA (r = 0.626, P < 0.01). Compared with men consuming diets with similar B-6 to protein ratios In a previous study, the women excreted a greater percentage of the B-6 intake as 4-PA, had lower plasma PLP concentrations and excreted greater amounts of postload urinary tryptophan metabolites at all three protein levels. If the Recommended Dietary Allowance (RDA) of vitamin B-6 is to be based on the dietary B-6 to protein ratio, gender differences in response to varying protein intakes should be considered. For the levels of protein intake used in this study and a B-6 intake of 1.25 mg/d, a B-6 to protein ratio of greater than 0.020 mg/g is required for adequate vitamin B-6 status in women.

Adult

Vaccine storage practices in pediatric offices.

Fifty pediatric offices and clinics in the metropolitan Los Angeles area were visited to assess vaccine storage practices. Questionnaires were administered to the personnel responsible for vaccine storage and the vaccine refrigerators were inspected. Only 16% of vaccine storage coordinators could cite appropriate storage temperatures for vaccines and 18% were unaware that heat can harm certain vaccines. Refrigerator thermometers were checked at least weekly in only 20% of offices, and 22% of the refrigerators had inappropriately high temperatures. Vaccines were routinely stored outside of the refrigerator uninsulated during the practice day in 16% of the offices visited. It is concluded that vaccine storage errors occur in pediatric offices at an unacceptably high frequency. Pediatricians should familiarize themselves with the guidelines for optimal vaccine storage in order to minimize the potential for vaccine failure in primary care practice.

Bacterial Vaccines

Validity of self-report of adaptive behavior skills by adults with mental retardation.

The validity of self-reports of 48 adults with mental retardation of daily living competency using the recently revised Vineland Adaptive Behavior Scales (Sparrow, Balla, & Cicchetti, 1984) was investigated. Self-report was compared to standard Vineland interviews of subjects' program counselors and to demonstrated competency in a real-life setting. On domains measuring adaptive skills, the subject and counselor interviews yielded highly consistent results. On the optional Maladaptive Behavior domain, however, the subjects with mental retardation underreported problematic behavior. Response validity and implications for use of self-report for program planning and placement decisions were discussed.

Activities of Daily Living

Reflex sympathetic dystrophy in children: treatment with transcutaneous electric nerve stimulation.

During the past 6 years, ten children with reflex sympathetic dystrophy were treated. Pain in an extremity was the initial complaint in all patients. The pain was unilateral in 90% of the patients; upper and lower extremities were affected with equal frequency. Tenderness to palpation, extreme hyperesthesia, and dysesthesia were other dominant features. All patients had some evidence of autonomic nervous system dysfunction in the affected extremity (swelling, color change, decreased temperature, and/or hyperhidrosis). The median duration of symptoms prior to referral and diagnosis was 5 months. All children were treated as outpatients with a transcutaneous electric nerve stimulator and home-based physical therapy. With this regimen, seven patients had complete remission within 2 months. Two other patients improved with transcutaneous electric nerve stimulation therapy, and one patient had no response to transcutaneous electric nerve stimulation. Reflex sympathetic dystrophy is frequently underdiagnosed in children. Increased awareness of this syndrome is important because accurate diagnosis is crucial and transcutaneous electric nerve stimulation offers a safe, simple, and effective outpatient therapy for reflex sympathetic dystrophy in children.

Adolescent

Pyridoxine supplementation: effect on lymphocyte responses in elderly persons.

The effect of pyridoxine supplementation on lymphocyte responsiveness was investigated in 15 persons aged 65-81 y. Eleven subjects received 50 mg/d pyridoxine HCl (PN). Four subjects received a placebo. Lymphocyte proliferation to T and B cell mitogens, lymphocyte subpopulations with monoclonal antibodies, and plasma pyridoxal 5'-phosphate (PLP) were measured before and after 1 and 2 mo of supplementation. After 1 and 2 mo plasma PLP levels increased by 195 +/- 88 nM and 201 +/- 84 nM, respectively, in subjects receiving PN. With PN supplementation, lymphocyte proliferation increased significantly in response to phytohemagglutinin (p less than 0.01), pokeweed mitogen (p less than 0.01), and Staphylococcus aureus (Cowain I) (p less than 0.05). For PN-treated subjects with low presupplement plasma PLP levels, lymphocyte blastogenesis also increased significantly (p less than 0.01) in response to concanavalin A. Percentages of T3+ and T4+ but not T8+ cells increased significantly (p less than 0.05) in PN-treated subjects. These results suggest that improving vitamin B-6 status is important in stimulating immunocompetence in the elderly.

Aged

Effect of dietary egg on variability of plasma cholesterol levels and lipoprotein cholesterol.

The effects of dietary cholesterol on plasma cholesterol levels, its distribution among lipoproteins, and apoproteins of high-density lipoprotein subclasses in individuals who did and did not demonstrate response in plasma cholesterol levels were studied in 21 healthy middle-aged men for 3 mo. After consumption of 3 eggs/day in addition to their habitual diets for 28 days, 21 subjects were divided into 8 hyper- and 13 hypo-responders. The average plasma cholesterol level of the 21 subjects was changed from 188 +/- 36 to 199 +/- 36 mg/100 ml over the 28-day classification period. During the same period the mean plasma cholesterol level of the hyper-responders was significantly increased (p less than 0.025) from 170 +/- 41 to 199 +/- 29 mg/100 ml while that of the hypo-responders fell slightly. The addition of six eggs to the daily diet of the hypo-responders did not alter the mean plasma cholesterol level but resulted in a wide difference in response of plasma cholesterol concentration. The 13 hypo-responders were divided into hypo-hyper-responders (n = 6) and hypo-hypo-responders (n = 7) depending upon the degree of change in plasma cholesterol level. The present study illustrated the variabilities of plasma cholesterol level among free-living subjects who demonstrated two-stage thresholds of response to dietary intake of cholesterol.

Adult

The effect of dietary protein on the metabolism of vitamin B-6 in humans.

Eight men, aged 21-31 yr, were fed semipurified diets containing 0.5 (low), 1.0 (medium) and 2.0 (high) g protein/kg body weight; vitamin B-6 intake was kept constant at 1.6 mg/d. Each level of protein was fed for 15 d. Urinary vitamin B-6 (UB-6), urinary 4-pyridoxic acid (4-PA), plasma total vitamin B-6 (PB-6) and plasma pyridoxal 5'-phosphate (PLP) were determined every third day. Means are reported for all subjects of values determined during the second half of each period. Concentration of urinary and plasma vitamin B-6 compounds were negatively correlated with protein intake: the correlation coefficient of nitrogen intake with 4-PA was -0.69 (P less than 0.01); with PLP, -0.45 (P less than 0.05); and with PB-6, -0.48 (P less than 0.05). The decrease in UB-6 was not statistically significant. These results indicate that with increased intake of dietary protein, vitamin B-6 is retained in the body for increased catabolism of amino acids. When evaluating vitamin B-6 requirements or status in humans, protein intake must be considered.

Adult

The effect of vitamin B6 deficiency on cytotoxic immune responses of T cells, antibodies, and natural killer cells, and phagocytosis by macrophages.

The effect of vitamin B6 on cytotoxic immune responses of T cells, natural killer (NK) cells, cytotoxic antibody production, and macrophage phagocytosis was assessed in 5-week-old female C57B1/6 mice. Mice were fed 20% casein diets with pyridoxine (PN) added at 7, 1, 0.1, or 0 mg/kg diet, which represents 700, 100, 10, and 0% of requirement, respectively. Compared to mice fed 7 or 1 mg PN diet, animals fed 0 or 0.1 mg PN diet showed significantly reduced primary splenic and peritoneal T-cell-mediated cytotoxicity (CMC). Animals fed 0 mg PN diet also showed significantly depressed secondary T CMC of splenic and peritoneal lymphocytes against P815 tumor cells. Complement-dependent antibody-mediated cytotoxicity against P815 cells, phagocytosis of SRBC by macrophages, and native and interferon-induced NK cell activities against YAC cells were not affected by the level of vitamin B6 intake. The percentage of macrophages present in the peritoneal exudate cells was increased in animals fed the 0 mg PN diet. The immune responses were not enhanced or altered by the excess intake of vitamin B6 (7 mg PN). It appears that vitamin B6 is an essential nutrient for maintenance of normal T-cell function in vivo.

Animals

The effect of vitamin B-6 deficiency on host susceptibility to Moloney sarcoma virus-induced tumor growth in mice.

The effect of vitamin B-6 deficiency on in vivo host susceptibility to primary Moloney sarcoma virus (MSV)-induced tumor growth and to secondary challenge with MSB sarcoma cells was examined in mice. Female C57BL/6 mice, 6 weeks of age, were fed 20% casein diets with pyridoxine (PN) added at 1, 0.5, 0.1 or 0 mg/kg diet for 21 weeks. After 4 weeks of dietary treatment the mice were challenged with MSV. Vitamin B-6 deficiency resulted in an enhancement of tumor susceptibility as well as an increase in tumor size and regression time. The animals resistant to both MSV and MSV-transformed tumor cells ( MSB ) challenge showed splenic tumor development at necropsy 51 days after MSB challenge. Total incidence of MSV/ MSB /splenic tumors was 2/11, 2/11, 4/10 and 8/11 in animals fed PN 1, 0.5, 0.1 and 0 diets, respectively. Since MSV-induced tumors regressed spontaneously in immunocompetent hosts, the increased susceptibility to MSV oncogenesis in vitamin B-6-deficient animals suggests that reactivity of T cells and/or other effector cells is impaired in vitamin B-6-deficient animals suggests that reactivity of T cells and/or other effector cells is impaired in vitamin B-6 adequacy.

Animals

Bioavailability to rats of selenium in various tuna and wheat products.

Bioavailability of selenium (Se) in tuna and wheat at various stages of processing was studied in rats. The protein source of the rat diets was torula yeast with Se supplied by either raw, precooked or canned tuna, or whole wheat flour, whole wheat bread or bran. Sodium selenite was used as the standard. Each Se source was fed at three levels: 0.05, 0.10 and 0.15 ppm. By using increase in glutathione peroxidase (GSH-Px) activity in liver, kidney and whole blood as an indicator of bioavailability, no differences were found among the three tuna products or among the three wheat products tested. However, significantly lower GSH-Px activity was found in the combined tuna groups as compared to the combined wheat groups, suggesting that selenium in wheat was more available than that in tuna. There was a significant increase in the liver Se content of rats fed all levels of Se in canned tuna and in kidney, blood and muscle Se of rats fed 0.10 and 0.15 ppm Se in canned tuna in comparison to the tissue Se content in rats fed these same levels of Se in raw or precooked tuna. Since this did not correspond with an increase in GSH-Px activity it was concluded that it did not represent increased bioavailability of canned tuna. Thus, food processing does not appear to affect Se availability, but Se appears to be more available in wheat than tuna.

Animals

Comparative vitamin B-6 bioavailability from tuna, whole wheat bread and peanut butter in humans.

Relative bioavailability of vitamin B-6 from tuna, whole wheat bread and peanut butter was investigated in eight men. The study was divided into a 10-day adjustment and three, 14-day experimental periods in a 3 X 3 Latin square design. Vitamin B-6 intake was set at 1.6 mg/day, with 50% of the intake coming from one of the three experimental foods and 50% from a basal diet. Daily complete urine and fecal collections were made. Urine was analyzed for 4-pyridoxic acid (4PA) and vitamin B-6, fecal samples for vitamin B-6 and plasma (sampled every 5 days) for pyridoxal 5'-phosphate (PLP). Mean values +/- SD for the adjustment, tuna, whole wheat bread and peanut butter periods were: 5.65 +/- 1.76, 4.89 +/- 1.10, 3.62 +/- 0.66 and 2.80 +/- 0.50 mumol/day for 4-pyridoxic acid; 0.98 +/- 0.34, 1.05 +/- 0.20, 0.76 +/- 0.09 and 0.68 +/- 0.19 mumol/day for urinary vitamin B-6; 2.72 +/- 0.94, 3.08 +/- 0.73, 3.80 +/- 0.78 and 4.42 +/- 1.03 mumol/day for fecal vitamin B-6 and 65.0 +/- 23.30, 64.8 +/- 29.80, 49.3 +/- 14.40 and 48.4 +/- 20.20 nM for plasma pyridoxal 5'-phosphate, respectively. 4PA and urinary vitamin B-6 excretion were significantly (P less than or equal to 0.01) higher in the tuna period than in either the whole wheat bread or peanut butter periods.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

The effect of wheat bran on the bioavailability of vitamin B-6 in young men.

The effect of cooked wheat bran on the bioavailability of vitamin B-6 (B-6) was determined in 10 men, aged 20 to 35 years. The subjects consumed a constant diet with and without the addition of 15 g wheat bran during three successive 18-day periods in a switch-back design. Half of the subjects received the additional bran during periods 1 and 3; the other half consumed the bran during period 2. The bran and nonbran diets supplied, respectively, 1.69 and 1.66 mg of B-6 daily. Plasma total B-6 and pyridoxal phosphate (PLP), urinary 4-pyridoxic acid (4-PA), and urinary and fecal B-6 were determined at regular intervals during each period. Bran significantly increased fecal B-6 (P less than 0.05) and decreased urinary 4-PA (P less than 0.01). Bran also significantly depressed plasma B-6 (P less than 0.01) and PLP (P less than 0.05). These results indicate that the addition of 15 g of wheat bran to the diet decreased the bioavailability of B-6. Since this decrease was modest, never exceeding 17% (based on urinary 4PA and B-6), this amount of bran will not adversely affect B-6 status when intake of the vitamin is adequate.

Adult