Prospective Assessment of Radiation in Pediatric Urology: The Pediatric Urology Radiation Safety Evaluation Study.

PURPOSE: Pediatric tissues are exquisitely sensitive to ionizing radiation from diagnostic studies and therapies involving fluoroscopy. We prospectively monitored radiation exposure in our pediatric urology patients during fluoroscopy guided operative procedures with single point dosimeters to quantify radiation dose. MATERIALS AND METHODS: Children undergoing fluoroscopy guided urological procedures were prospectively enrolled in the study from 2013 to 2015. Single point dosimeters were affixed to skin overlying the procedural site for the durations of the procedures to record dosimetry data. Patient demographics, procedural variables and fluoroscopic settings were recorded. RESULTS: A total of 78 patients underwent 96 procedures, including retrograde pyelography, ureteral stent insertion, ureteroscopy and percutaneous nephrolithotomy. Median patient age was 12 years (range 0.3 to 17) and median body mass index percentile for age was 70.7 (1.0 to 99.1). Median skin entrance radiation dose for all procedures performed was 0.56 mGy. Median dosages associated with the 29 diagnostic procedures and 49 definitive interventions were 0.6 mGy (mean 0.8, range 0.1 to 2.2) and 0.7 mGy (1.1, 0.0 to 5.5), respectively. The dose associated with the 18 procedures of temporization was significantly higher by comparison (median 1.0 mGy, mean 2.6, range 0.1 to 10.7, p = 0.02). CONCLUSIONS: Pediatric radiation exposure is not insignificant during urological procedures. Further multi-institutional work would provide context for our findings. Protocols to optimize fluoroscopic settings and minimize patient exposure, and guidelines for radiation based imaging should have a key role in all pediatric radiation safety initiatives.

Manganese-Enhanced MRI of the Brain in Healthy Volunteers.

BACKGROUND AND PURPOSE: The manganese ion is used as an intracellular MR imaging contrast agent to study neuronal function in animal models, but it remains unclear whether manganese-enhanced MR imaging can be similarly useful in humans. Using mangafodipir (Teslascan, a chelated manganese-based contrast agent that is FDA-approved), we evaluated the dynamics of manganese enhancement of the brain and glandular structures in the rostral head and neck in healthy volunteers. MATERIALS AND METHODS: We administered mangafodipir intravenously at a rate of 1 mL/minute for a total dose of 5 µmol/kg body weight. Nine healthy adult volunteers (6 men/3 women; median age, 43 years) completed baseline history and physical examination, 3T MR imaging, and blood work. MR imaging also followed mangafodipir administration at various time points from immediate to 7 days, with delayed scans at 1-3 months. RESULTS: The choroid plexus and anterior pituitary gland enhanced within 10 minutes of infusion, with enhancement persisting up to 7 and 30 days, respectively. Exocrine (parotid, submandibular, sublingual, and lacrimal) glands also enhanced avidly as early as 1 hour postadministration, generally resolving by 1 month; 3 volunteers had residual exocrine gland enhancement, which resolved by 2 months in 1 and by 3 months in the other 2. Mangafodipir did not affect clinical parameters, laboratory values, or T1-weighted signal in the basal ganglia. CONCLUSIONS: Manganese ions released from mangafodipir successfully enable noninvasive visualization of intra- and extracranial structures that lie outside the blood-brain barrier without adverse clinical effects, setting the stage for future neuroradiologic investigation in disease.

Estrogen metabolism and excretion in Oriental and Caucasian women.

BACKGROUND: Caucasian and Oriental women have different incidence rates of breast cancer. Among the underlying risk factors for the development of breast cancer in the women of these two groups may be their different diets and patterns of estrogen metabolism and excretion. The absolute levels and relative ratios of 16 alpha-hydroxylated estrogens and 2-hydroxylated estrogens (catechol estrogens) in the body may have a role in the etiology of breast cancer, but studies so far have provided only conflicting results. PURPOSE: Our goal was to study estrogen metabolism, in particular, the extent of 2-hydroxylation and 16 alpha-hydroxylation of estrogens in two groups of women, one Caucasian and one Oriental, with inherently different breast cancer risks. METHODS: Dietary records were analyzed over 3-day periods in the mid-follicular phase, twice, at 6-month intervals for 13 premenopausal Oriental women, recent immigrant arrivals in Hawaii with presumed low risk of breast cancer, and for 12 premenopausal Finnish women with presumed higher risk. The urinary estrogen profile was measured by gas chromatography-mass spectrometry and plasma and fecal estrogens were assayed by chromatographic radioimmunoassays. RESULTS: Mean fat intake per 1000 kcal was 73% higher (P < .001) in the Finnish women, but the mean fiber intake and fecal weights were similar to those of the Oriental women. Compared with Oriental women, Finnish women had 46% higher plasma estradiol (P < .01) and 124% higher plasma estrone sulfate (P < .01); however, after adjustment for differences in age and body mass index, only the difference in estrone sulfate remained statistically significant (P < .05). Mean plasma levels of estrone and estradiol correlated with height after adjustment for body mass index (P < .05). Mean plasma levels of estrone and sex hormone-binding globulin were similar. The Finns had higher mean urinary estrone (193%), estradiol (166%), various catechol estrogens (130%-439%), and total estrogen excretion (123%) (all P < .001), but similar 16 alpha-hydroxylated estrogen excretion. As calculated, 16 alpha-hydroxylation of estrone was significantly increased (P < .01) in the Oriental women, but 2-hydroxylation, 4-hydroxylation, and 16 beta-hydroxylation of estrone were similar in both groups. The ratio of catechol estrogen to 16 alpha-hydroxylated estrogen was four to five times higher (P < .001) in the Finnish women. The Oriental women had two to three times higher fecal excretion of estrogens than the Finnish women (P < .01). CONCLUSIONS: Our results indicate that high catechol estrogen formation may be a greater risk factor for breast cancer than high 16 alpha-hydroxylation of estrogens. However, the main risk factor for the Finnish women, as opposed to the Oriental women, may be their higher estrogen levels that result from a higher fat diet, higher estrogen production related to their greater height, and lower fecal estrogen excretion.

Breast cancer: weighing the evidence for a promoting role of dietary fat.

It has been hypothesized that a high-fat diet promotes the development of postmenopausal breast cancer. This contention is supported by data showing high international correlations between fat intake and breast cancer rates, modest positive associations with a high-fat diet in case-control studies, and animal model studies that have consistently demonstrated that dietary fat influences mammary cancer development at several stages in the carcinogenic process. A number of plausible biologic mechanisms have been suggested that may explain such promotional effects. In contrast, dietary fat intake is unrelated to the risk of breast cancer in cohort studies. The conflicting findings from cohort studies have created uncertainty regarding nutritional recommendations and breast cancer prevention. After reviewing key scientific findings that are relevant to this issue, the following conclusion is drawn: In the absence of data from dietary intervention trials, the weight of available evidence suggests that the type and amount of fat in the diet is related to postmenopausal breast cancer and that the inability to detect associations within populations (cohort studies) is because of measurement error and the relative homogeneity of diets measured. It is expected that the results from intervention trials will clarify this issue.

Effect of diet on excretion of estrogens in pre- and postmenopausal women.

Fecal, urinary, and plasma estrogens and plasma androgens were studied in healthy pre- and postmenopausal vegetarian and omnivorous women. Dietary histories of the subjects revealed that omnivores consumed a higher percentage of total protein and fat from animal sources. The total 72-hr fecal excretion as measured by dry weight was higher for vegetarians. Preliminary results indicate that vegetarian women excrete 2 to 3 times more estrogens in feces than do omnivores and that omnivores have about 50% higher mean plasma level of unconjugated estrone and estradiol than vegetarians. Estriol-3-glucuronide, a compound that is formed upon reabsorption of free estriol from the intestine, is found in lower concentrations in the urine of vegetarians. These data suggest that in vegetarians a greater amount of the biliary estrogens escape reabsorption and are excreted with the feces. The differences in estrogen metabolism may explain the lower incidence of breast cancer in vegetarian women.

Health aspects of vegetarian diets.

Recent studies of vegetarian diets and their effects on morbidity and mortality are reviewed. Vegetarian diets are heterogeneous as are their effects on nutritional status, health, and longevity. Mortality rates are similar or lower for vegetarians than for nonvegetarians. Risks of dietary deficiency disease are increased on vegan but not on all vegetarian diets. Evidence for decreased risks for certain chronic degenerative diseases varies. Both vegetarian dietary and lifestyle practices are involved. Data are strong that vegetarians are at lesser risk for obesity, atonic constipation, lung cancer, and alcoholism. Evidence is good that risks for hypertension, coronary artery disease, type II diabetes, and gallstones are lower. Data are only fair to poor that risks of breast cancer, diverticular disease of the colon, colonic cancer, calcium kidney stones, osteoporosis, dental erosion, and dental caries are lower among vegetarians. Reduced risks for chronic degenerative diseases can also be achieved by manipulations of omnivorous diets and lifestyles.

Human studies on the effects of fatty acids on cancer: summary, gaps, and future research.

Both the goal of understanding the basic biology of cancer development as well as the practical considerations involving public health, marketing, and nutrition education have stimulated interest on the effects of individual fatty acids on cancer. Data on diet-disease relations must meet the standard of significant scientific agreement based on the totality of publicly available scientific evidence. The process of arriving at significant scientific agreement begins by collecting data accumulated from epidemiologic associations, animal studies, and clinical trials. This supplement represents one useful effort toward that end. Questions raised include: 1) What stage of the disease is being studied, what are the relevant characteristics of the study participants, how well characterized was the diet, and were appropriate experimental designs used; 2) Is there is a significant role for markers of disease and, if so, are the markers available; 3) Is there consistency, strength, and quality of evidence for establishing basic scientific relations; 4) Do dose-response relations, biological plausibility, and temporal relations (with special attention to clinical trials) exist; 5) What is the level of specificity of the data for the health claim or posited relation; and 6) What are the effective amounts of fatty acids in foods and diet? More complete food-composition data with respect to fatty acids and more comprehensive food tables are needed, as are better methods for measuring fat intakes, better markers of progression, and more definitive epidemiologic and clinical studies. At present there is insufficient evidence to conclude that specific fatty acids are associated with cancer development in humans.

Vegetarian eating patterns: science, values, and food choices--where do we go from here?

Many aspects of vegetarian diets are currently of interest from a health standpoint. It is becoming increasingly important to recognize that both values and scientific issues come into play in evaluating data on diet and nutrition.

Vegetarian children: appropriate and inappropriate diets.

Acceptable and appropriate vegetarian diets fulfill the Recommended Dietary Allowances and other authoritative dietary guidelines dealing with balance, variety, moderation, and developmental appropriateness of diets for children. Vegetarian regimes currently fed to infants and children are evaluated using these criteria. Vegan-like diets, fed early in infancy and childhood, pose special problems with respect to sufficiency of certain nutrients, energy, and bulk, especially if they are unplanned and unaccompanied by ongoing health supervision. Lactovegetarian, lactoovovegetarian, and semivegetarian patterns are more likely to be satisfactory. They conform closely with the pediatric recommendations for promoting health and reducing risks of chronic degenerative diseases, are sufficient without being excessive in nutrients, are low in bulk, and are developmentally appropriate.

Insights into dietary recall from a longitudinal study: accuracy over four decades.

We studied the validity and consistency of memory of foods consumed decades earlier in a longitudinal population of 91 persons. The memory of middle-aged persons for food intake years earlier did not decline invariably over time, although median correlations between actual and recalled consumption decreased. Time-related memory loss varied greatly from food to food. Neither analyses of group mean differences and SDs over all foods nor those for individual foods provided clearcut evidence of time-related memory loss. Systematic biases in memories of dietary intakes in the distant past were evident, depending on current diet and varying according to individual foods and food groups. These discrepancies may represent either misremembering or the effects of inferential processes. Examination of the consistency (reliability) and validity of reports of food intake indicated that validity estimates provided by mean differences between recalled and actual intakes were more revealing than correlation coefficient. Consistent reports were not necessarily valid, as indicated by memories of food intake. Correct inferences may have been made even when the actual memory was lost.

Body mass index from childhood to middle age: a 50-y follow-up.

The tracking of body mass index (BMI) over a 50-y period in a longitudinal study was examined by using both correlation coefficients and the Foulkes-Davis tracking index. Over the long term, BMIs before maturity were poor predictors of middle-aged BMI status in females but were good predictors in males. The correlation between females' BMI in childhood and their BMIs at two points during middle age (40 and 50 y) was zero; in males it was r = 0.36 and 0.41, respectively. Between-age correlations were high (P less than 0.0001) for both sexes, reflecting stability in BMI over the shorter term (less than or equal to 10 y). The tracking of BMI (with the Foulkes-Davis tracking index) from childhood to middle age was better for males than for females (P less than 0.1). Linear-regression analysis was also used to assess the predictability of relative body size in middle age from earlier measures; BMI in childhood accounted for 0% of the variance in females and 17% in males. We conclude that the prediction of ponderosity in middle age from BMIs early in life is more reliable for males than for females.

Genetic and environmental influences on eating patterns of twins aged >/=50 y.

BACKGROUND: Clinicians and researchers could benefit from a greater understanding of the role of genetic and environmental factors in human eating behavior. OBJECTIVE: Our aim was to estimate the relative influence of genetic and environmental factors on habitual eating patterns in middle-aged and elderly men and women. DESIGN: Male and female twins (n = 4640) aged >/=50 y completed a mailed version of the National Cancer Institute food-frequency questionnaire. Factor analysis was performed to identify eating patterns among respondents. Estimates of genetic, common environmental (shared by family members), and specific environmental (unique to an individual) influences were obtained for food use, serving size, and consumption frequency by comparing monozygotic and dizygotic twin-pair groups with structural equation analysis. RESULTS: Two independent eating patterns were identified: the first consisted of items high in fat, salt, and sugar, and the second reflected healthful eating habits. Although the influence of environmental factors was larger, between 15% and 38% of the total variation in pattern 1 and between 33% and 40% in pattern 2 were explained by genetic influences. Models accounting for sex differences in genetic and environmental estimates fit the data significantly better for food use and serving size of foods in eating pattern 1 and for food use in eating pattern 2. CONCLUSION: Although 60-85% of the variability in eating patterns was associated with environmental factors, genetic influences were also apparent and there was some evidence of sex specificity. These findings may be important in crafting dietary interventions and predicting adherence to these interventions.

Relationship of diet to root caries.

A Nutrition and Oral Health Study was conducted on 141 middle-aged and elderly adults (54% female and 46% male; aged 47-83 y, mean = 67; 51% college educated; and 89% white). This study reports on the relationship between root caries and diet. Nutritional composition was derived from two 3-d food diaries. Root caries was measured according to the 1985 Adult Survey Diagnostic Criteria of the National Institute of Dental Research. When the individuals were segregated by their root DFS (decayed and filled surfaces) status into highest (> or = 7) and lowest (< or = 1) quartiles, the sucrose consumption was significantly higher in the higher DFS group. Mean energy consumption and mean number of teeth were the same in both groups. When the individuals were segregated by sucrose consumption into highest (> or = 89 g) and lowest (< or = 31 g) quartiles, DFS root status was significantly higher (P < 0.01) in the highest quartile group (7 g) vs the lowest group (4 g). By using data from subjects with two food diaries, a stepwise-linear-regression model for root caries showed that 4.2% of the variance for root caries was explained by sucrose, 2.8% by plaque, 3.8% by total number of teeth, and 5.6% by gingival recession. These data suggest that root caries has a similar dietary etiology to coronal caries.

Long-term memory of body weight and past weight satisfaction: a longitudinal follow-up study.

Recalled body weight and self-reported current weight were validated in a longitudinal study population by comparing recalls at 50 y to actual measures taken at ages 18, 30, 40, and 50 y. Recalled body weights were also compared with reported desired weights at these same ages. Self-reported weights at 50 y were equally accurate for both males and females; the mean reporting underestimate was -1.98 kg for males and -1.86 kg for females. Males' self reports at age 50 y were influenced by years of education (P less than 0.005) and current body size (P less than 0.0001) whereas females' were not. Correlations between recall of past weights and measured weights ranged from r = 0.87 at 18 y to 0.95 at 40 y. Recalls of past body weight were not significantly influenced by the passage of time, the number of years of education, or the accuracy of current weight reports. Current body size (wt/ht2) was significantly associated with life-time weight dissatisfaction in both sexes (P less than 0.0005).

Growth in "new" vegetarian preschool children using the Jenss-Bayley curve fitting technique.

Length and weight measurements obtained on 142 vegetarian and 229 nonvegetarian school children from a normative population were fitted to growth curves using the asymptotic nonlinear regression equation of Jenss and Bayley. All of the children were Caucasian and age ranged from a few weeks to 6 yr. The growth curves obtained for vegetarian children were from 0.5 to 1.0 kg and 1 to 2 cm lower, depending on age, sex, and diet, than were curves for reference populations of nonvegetarian children. Length was affected more than weight. Macrobiotic vegetarian children's curves were more depressed than those of the other vegetarian children, indicating that there was a good deal of heterogeneity in growth within vegetarians which was associated with dietary group characteristics. Measurements of females were more consistently affected than males, and their diets were also more far reaching with respect to animal food avoidances. The analysis of food records available provided evidence that energy intakes of the vegetarians were below recommended levels, whereas protein intakes did not appear to be limiting.

Nutritional status of vegetarian children.

Thirty-nine preschool children consuming different types of vegetarian diets were studied. Type and amount of carbohydrate, fat, protein, and amount of sodium and cholesterol provided by their diets were more like intakes suggested in the proposed Dietary Goals for the United States than to levels in usual diets of nonvegetarian children. Macrobiotic vegetarian children consumed less animal food than did other vegetarian children. The mean intake of vitamin D of macrobiotics was an eighth of the Recommended Dietary Allowance and mean serum alkaline phosphatase values were elevated. The mean intake of vitamin B12 levels were normal. Vegan macrobiotic children had the lowest intakes of vitamins B12 and D. Other vegetarians' mean intakes of these vitamins met the Recommended Dietary Allowance. Mean iron intakes of the vegetarians approximated the Recommended Dietary Allowance. Hematological indices were suggestive of mild iron deficiency anemia in a quarter of subjects. Serum cholesterol values were low for the group. Physical measurements were within normal limits and macrobiotic vegetarians were not smaller or leaner than other vegetarian children. The nutritional difficulties discovered could be corrected by careful planning of vegetarian children's diets while preserving the beneficial qualities of the diet in other respects.

Diet and plasma androgens in postmenopausal vegetarian and omnivorous women and postmenopausal women with breast cancer.

We studied 27 postmenopausal women, 9 vegetarians, 10 omnivores, and 8 apparently healthy women with breast cancer (BC), four times during 1 y. Dietary intakes were recorded and plasma androgens and sex-hormone-binding globulin (SHBG) binding capacity were determined. Androstenedione (A), testosterone (T), free T (FT), and SHBG were higher in omnivores than in vegetarians. In multiple correlation analysis, intakes of protein and fat were positively correlated with A, T, and FT, whereas the intakes of carbohydrate, grain, total fiber, and grain fiber showed the opposite correlations. Protein intake was positively correlated with percentage FT (%FT) and negatively with SHBG. BC patients had a similar pattern to omnivores with even higher levels of A and T (significant compared with vegetarians) and they showed significantly higher FT and lower SHBG than both control groups. We conclude that a Western-type diet in postmenopausal women is associated with high A, T, %FT, FT, and low SHBG and this pattern was apparent in the BC patients.

The relationship between estrogen levels and diets of Caucasian American and Oriental immigrant women.

The relationship between diet and estrogens was studied in two groups of women with different dietary habits and breast cancer risks. Plasma estrogens and androgens and 24-h urinary and fecal excretion of estrogens were measured in premenopausal and postmenopausal Caucasians and recent Oriental immigrants from Southeast Asia to Hawaii. Premenopausal Caucasians had 30-75% higher plasma estrone and estradiol levels than their age-matched cohorts in Hawaii, and the postmenopausal Caucasians had 3-fold higher plasma levels of estradiol. The Oriental women excreted more than twice the amount of estrogen in their feces but they excreted significantly less in their urine. Thus, the ratio of urinary-to-fecal excretion was approximately 3-5 times higher in young Caucasian women. Analysis of dietary components and plasma estrogens in premenopausal women showed a positive correlation between daily intake of total fat and saturated fat and plasma estrone and estradiol concentrations.

Low-fat, high-fiber diet and serum estrone sulfate in premenopausal women.

The effect of diet on serum estrogen levels was investigated in 17 healthy premenopausal women consuming defined diets prepared in a metabolic unit. During an initial 4-wk control period all women consumed a typical Western diet (40% of total calories from fat, 400 mg cholesterol/d, 12 g dietary fiber/d, and a ratio of polyunsaturated to saturated fatty acids [P:S] of 0.5). After this control period they were switched to a low-fat, high-fiber diet for 8-10 wk, which consisted of 25% of calories from fat, P:S of 1.0, cholesterol of 200 mg cholesterol/d, and 40 g dietary fiber/d. Compared with the control period 16 of 17 women had lower serum estrone sulfate levels on the low-fat, high-fiber diet. There was an average decrease of 36% with mean levels decreasing from 2.11 +/- 0.25 nmol/L (means +/- SEM) on the control diet to 1.29 +/- 0.19 nmol/L on the experimental diet (p less than 0.001). We conclude that a low-fat, high-fiber diet can significantly reduce serum estrone sulfate levels.

Lack of efficacy of a food-frequency questionnaire in assessing dietary macronutrient intakes in subjects consuming diets of known composition.

BACKGROUND: We compared the validity of a semiquantitative food-frequency questionnaire in assessing intakes of macronutrients (absolute amounts and percentages of energy) by 19 subjects fed natural-food diets of known composition. In small subsets (n = 5 or 6), we also tested 3-d diet records. OBJECTIVE: The objective of this study was to investigate the efficacy of food-frequency questionnaires and diet records in subjects fed natural-food diets of known composition. DESIGN: Each subject consumed 3 different diets for >/=6 wk and self-reported his or her food intake by using a food-frequency questionnaire and a diet record. The diets varied in their chemically analyzed contents of fat (15-35% energy), saturated fat (5-14%), monounsaturated fat (5-14.5%), polyunsaturated fat (2.5-10.5%), carbohydrate (49-68%), and cholesterol (108-348 mg/d). RESULTS: The food-frequency questionnaire significantly underestimated fat, saturated fat, monounsaturated fat, and protein intakes and significantly overestimated carbohydrate intake with the high-fat diet. The percentage of energy from fat was significantly underestimated for the high-fat diet and significantly overestimated for the very-low-fat diet. Estimates from the food-frequency questionnaire differed significantly from actual intakes for fat (absolute and percentage), saturated fat (absolute and percentage), monounsaturated fat (absolute and percentage), and protein (percentage) in the high-fat diet and for polyunsaturated fat (absolute and percentage), saturated fat (percentage), fiber (absolute), and cholesterol (daily absolute; in mg/d) in the lower-fat diet. Estimates from the diet records better agreed with actual intakes than did estimates from the food-frequency questionnaire except for monounsaturated fat (absolute and percentage) in the high-fat diet and polyunsaturated fat (percentage) in the lower-fat diet and the very-low-fat diet. CONCLUSION: Our data indicated that the food-frequency questionnaire did not provide reliable estimates of absolute amounts of dietary fats or cholesterol.