Anthropometric correlates of lipoprotein profile and blood pressure in high BMI African American children.

OBJECTIVE: To explore the association of anthropometric indices with lipoprotein profile and blood pressure as risk factors of cardiovascular disease, in African American (AA) children. METHODS: A cross-sectional analysis was carried out on children aged 9-13 years with BMI >85th percentile. Height, weight, waist and hip circumferences, % body fat and blood pressure [systolic (sBP) and diastolic (dBP)] were measured. Fasting plasma levels of triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), intermediate density lipoprotein cholesterol (IDL-C) and very low-density lipoprotein cholesterol (VLDL-C) were analysed. RESULTS: After accounting for age, gender and pubertal status of the child, multiple linear regression models showed that waist circumference and BMIz were strong predictors for lipoprotein variables. In independent analysis, waist circumference and BMI z-scores were found to be interdependently associated with TG, LDL-C:HDL-C ratio, VLDL-C and sBPz. However, for HDL-C, TG:HDL-C ratio and dBPz, waist circumference was independently and more strongly associated with these risk factors than BMI. CONCLUSION: Waist circumference was a stronger predictor for lipoprotein variables and blood pressure in high BMI AA children than other anthropometric indices, and may be adequate as a screening test to identify children who are at increased risk for cardiovascular disease.

Repeated consumption of high-fiber breakfasts: effects on postprandial glucose and insulin responses after breakfast and lunch.

The objective of this study was to evaluate the effects of repeated consumption of two high-fiber diets on postprandial glucose and insulin responses. Two mixed-food breakfast meals composed predominantly of either red kidney beans or bran cereal were fed to six healthy young men. The meals provided equivalent levels of digestible carbohydrate, protein, fat, and fiber. Insulin responses measured after breakfast were lower with the bean diet than with the bran cereal diet but higher when measured after a standard lunch. No significant interactions were found between the diets and the length of the time the subjects were on the diets (days 1 vs 7). In comparison to the postprandial responses on day 1 of the diet periods, postprandial responses on day 7 showed reduced glucose and insulin responses to breakfast and reduced insulin responses to lunch. Responses to an oral glucose tolerance test were not affected by repeated consumption of these diets.

High-fiber foods at breakfast: influence on plasma glucose and insulin responses to lunch.

This study evaluates acute effects of red kidney bean consumption on postprandial glucose and insulin responses in six healthy young men. Comparisons were made among three mixed-food breakfast meals comprised predominantly of either red kidney beans, bran cereal, or white bread. These meals provided equivalent levels of digestible carbohydrate, protein, and fat. The bean and bran meals contained equivalent levels of fiber while the white-bread meal contained a lower level. The postprandial glucose and insulin responses to the three meals were similar and responses also were similar after a standard whole-wheat-bread meal 4 h later. There appeared to be a reciprocal relationship between glucose and insulin responses after the lunch meal. This would influence interpretation of data regarding second-meal response.

Influence of frequent and long-term consumption of legume seeds on excretion of intestinal gases.

The objective of this study was to determine the influence of long-term and frequent consumption of legume seeds on the excretion of fermentation gases. This was done by comparing gas excretion for one group (B) of individuals that habitually consumed legumes to that of another group (NB) of individuals that only infrequently consumed legumes. Gas excretion was measured during one diet period (control) when they consumed their normal diets and during one diet period (bean) when they consumed 100 g (dry weight), daily, of red kidney beans. Twelve men participated in this study on an outpatient basis and received each diet for 23 days. We found that there was neither short-term (no difference throughout the 23 days) nor long-term (NB and B groups were equivalent) adaptation in the quantity of gas that was excreted. However, both groups subjectively expressed greater tolerance and less physical discomfort as the bean-consuming period continued.

High-fiber diets: influence on characteristics of cecal digesta including short-chain fatty acid concentrations and pH.

The effects of two sources of dietary fiber on the characteristics of cecal contents were assessed directly with miniature swine cannulated to facilitate frequent collections of cecal digesta. The short-chain fatty acid (SCFA) concentrations increased and the pH decreased at the same time that meal constituents entered the cecum; PEG was used as a dietary marker. The bean diet resulted in higher concentrations of acetate and total SCFA in cecal digesta, lower concentrations of butyrate, a larger SCFA pool size, and a more acidic pH than did the bran diet. Thus, we conclude that SCFA concentrations and acidity of the digesta are directly related and that dietary fibers can affect simultaneously several variables that are implicated as factors influencing colonic health.

Influence of frequent and long-term bean consumption on colonic function and fermentation.

The objective of this study was to determine the influence of frequent and long-term consumption of legume seeds on colonic function. Two groups of subjects were studied--one group habitually consumed legume seeds as part of their normal diet, a second group only infrequently consumed legumes. No differences between these groups could be detected for fecal output and frequency, intestinal transit time, VFA excretion or fecal pH during 23-day study periods in which subjects consumed either their usual diet or 100 g red kidney beans, daily. However, the addition of beans to the diets of both groups provided significantly more dietary fiber, and produced greater fecal output and a higher concentration of VFA in feces. Fecal output appeared to be determined by two independent parameters--dietary fiber intake and VFA excretion. Beans provided a physiologically useful source of dietary fiber and favorably influenced colonic function.

Aging stimulates fatty acid oxidation in rat colonocytes but does not influence the response to dietary fiber.

Metabolism was studied in colonocytes isolated from young (4 mo) and aged (24 mo) Fischer 344 rats. Animals were fed fiber-free, low-fiber (5% cellulose), or high-fiber (oat bran or NIH 31 stock) diets. Colonocytes isolated from aged animals oxidized both short- and long-chain fatty acids at significantly higher rates than did colonocytes isolated from young animals. No differences between the young and aged were noted for the oxidation to CO2 of glucose and glutamine or for flux of glucose through glycolysis. Net adenosine triphosphate (ATP) production by colonocytes was calculated to be 20% higher for the aged than for the young, although the relative contribution of substrates to net ATP production from exogenous substrates was similar for the young and aged (45-50% from butyrate, 20-25% from glucose, and 30% from other substrates including acetate, propionate, palmitate, and glutamine). Substrate oxidation was generally higher in colonocytes from the oat bran (17% total dietary fiber, highly soluble fiber) versus fiber-free diet.

Analysis of volatile fatty acids in biological specimens by capillary column gas chromatography.

A method was developed to analyze and quantify volatile fatty acids (VFA) such as acetic, propionic, butyric, isobutyric, valeric and isovaleric acids in biological specimens. To obtain good sample transfer into the chromatographic system an organic solvent had to be used together with an aqueous milieu, thus improving wetting properties of the liquid sample plug introduced into the column. Sample preparation was carried out under alkaline conditions in order to exclude or minimize sample losses due to sample transfer during the extraction and work-up procedure. A cold on-column injection was applied to avoid irregular discrimination of the various acids due to sample splitting and an automatic injection technique was used to accommodate the large number of samples generated from biological origin. Connection of a pre-column of wide internal diameter (0.53 mm) to the analytical column (0.32 m) was optimized and adapted to the nature of the injection solvent mixture consisting of acetonitrile, water and hydrochloric acid. To obtain well-separated and correctly quantifiable gas chromatographic peaks, it was essential to perform the chromatography under acidic aqueous conditions. Standard resolution conditions and response factors were evaluated. The chromatographic results of applying this method to biological specimens from both rats and humans are provided.

Effects of cigarette smoking on phobic anxiety.

Smokers report that smoking reduces anxiety. However, experimental research on the anxiety-reducing effects of smoking is limited to two self-report studies, both of which have methodological problems. We tested the effects of smoking on self-reported anxiety and avoidance behavior in a behavioral avoidance test (BAT) using a large white rat. In a counterbalanced within subjects design, 20 rat phobic female smokers smoked or were smoking deprived in two separate administrations of the BAT. A second group of 20 rat phobic nonsmokers also received two BATs. Subjects manifested substantial anxiety during BATs. However, neither smoking condition nor smoker versus nonsmoker status affected self-reported or motoric anxiety. Although smoking did not reduce anxiety in this study, smoking may affect anxiety in other situations, such as social settings, where the stimulus is more diffuse or less intense. It may also affect anxiety in individuals who are heavier smokers than our subjects, who smoked only 10-20 cigarettes per day.

Imperforate anus in females: frequency of genital tract involvement, incidence of associated anomalies, and functional outcome.

Of 162 female patients with imperforate anus, 21% had a noncommunicating and 79% a communicating anomaly of the rectum or anus. Associated anatomical abnormalities were found in the lower urinary tract (15%), upper urinary tract (25%), lower genital tract (27%), upper genital tract (35%), and additional organ systems (51%). Death occurred in 26 patients and in 19, this was attributed to the associated abnormalities. Functional outcome was assessed in those patients 13 years of age or older. Bowel function was normal or near normal in 85%, as was urinary and renal function. In 44% of patients evaluated, there was persistent vaginal abnormality or scarring and in 25%, this was severe enough to require future surgery.

A randomized controlled trial of ultrasound-guided peripherally inserted central catheters compared with standard radiograph in neonates.

OBJECTIVE: The placement of a peripherally inserted central catheter (PICC) routinely incorporates tip position confirmation using standard radiographs. In this study, we sought to determine whether real-time ultrasound (RTUS) could be used to place a PICC in a shorter time period, with fewer manipulations and fewer radiographs than the use of radiographs to determine accurate placement. STUDY DESIGN: This was a prospective, randomized, trial of infants who required PICC placement. Catheters were placed using either standard radiograph, with blinded evaluation of the catheters using RTUS or with RTUS guidance, with input on catheter tip location. The number of radiographs required to confirm proper positioning, duration of the procedure and manipulations of the lines were recorded for both groups. Final confirmation of PICC placement was by radiographs in both groups. RESULT: A total of 64 patients were enrolled in the study, with 16 failed PICC attempts. Of the 48 remaining infants, 28 were in the standard placement group and 20 were in the RTUS-guided group. The mean ± s.d. gestational ages and weight at time of placement were 30 ± 4 weeks and 1229 ± 485 g, respectively. The RTUS use significantly decreased the time of line placement by 30 min (P=0.034), and decreased the median number of manipulations (0 vs 1, P=0.032) and radiographs (1 vs 2 P=0.001) taken to place the catheters. Early identification of the PICC by RTUS was possible in all cases and would have saved an additional 38 min if radiographs were not required. CONCLUSION: In the hands of ultrasound (US)-experienced neonatologists, RTUS-guided PICC placement reduces catheter insertion duration, and is associated with fewer manipulations and radiographs when compared with conventional placement.

Ultrasound-guided umbilical catheter insertion in neonates.

OBJECTIVE: Umbilical catheter placement is a routine neonatal emergency procedure that has large variability in technical methods. Commonly used methods are unable to accurately estimate insertion lengths, and X-rays cannot always identify malpositioned catheters. In clinical practice, the placement of umbilical lines takes time away from nursing during a critical transition period. Ultrasound is a safe and commonly used tool in the nursery for clinical management of sick neonates and has been shown to readily identify central catheter tip position. In this study, we sought to determine a more time-efficient and accurate means of umbilical catheter placement using bedside ultrasound. STUDY DESIGN: This is a prospective, randomized, pilot trial of infants of any age or weight admitted to the neonatal intensive care unit who required umbilical catheter placement. Infants were excluded if they had congenital heart disease, abdominal wall defects or had a single umbilical artery. Catheters were placed using either the conventional method, with blinded evaluation of the catheters using ultrasound, or with ultrasound guidance, with input pertaining to catheter tip location. The number of X-rays required to confirm proper positioning, completion time points throughout the procedure and manipulations of the lines were recorded for both groups. RESULT: Ultrasound use decreased the time of line placement with an average saving of 64 min, as well as decreased the number of manipulations required and X-rays taken to place the catheters. The average X-ray time from request to viewing per X-ray was 40 min for all subjects. CONCLUSION: Ultrasound-guided umbilical catheter placement is a faster method to place catheters requiring fewer manipulations and X-rays when compared with conventional catheter placement.

Preparation of high-fructose syrup from the tubers of the Jerusalem artichoke (Helianthus tuberosus L.

Fructose has recently received much attention due to renewed interest in natural sweeteners. In addition, fructose has some advantages to sucrose in sweetness, solubility, viscosity, and dental health characteristics. Fructose is deposited as storage fructans of the inulin (beta-1,2) type in tubers and rhizomes of the Compositae family. The utilization of the Jerusalem artichoke (Helianthus tuberosus) tuber as a source of fructose syrup is discussed. This plant has the potential to produce more sugar per acre than corn or sugar beets. In addition, the artichoke has higher frost resistance and lower heat unit requirements than corn and is somewhat more tolerant to low moisture conditions than sugar beets. A high quality fructose syrup can be produced from artichoke tubers. The extraction step was found to be particularly important since development of adverse colors and flavors must be prevented. The fructans may be acid or enzyme hydrolyzed but the latter method gave a higher quality syrup. Ion-exchange resins and activated charcoal were effective in removing coloring and flavoring materials, and also reduced other noncarbohydrate constituents. Since the enzymatic hydrolysis of the fructans is an attractive alternative to acid hydrolysis, a process was developed for producing and purifying a special beta-fructofuranosidase (inulase) from Saccharomyces fragilis. Inulase has a much higher specificity for fructans than commerically available beta-fructofuranosidase (invertase).

Wheat bran and corn oil do not influence proliferation in the colon of healthy rats when energy intakes are equivalent.

Dietary intakes of fiber (wheat bran) and fat (corn oil) by rats were quantitatively varied for 6 wk while intakes of energy and essential nutrients were constant among the diets. The influence of wheat bran and corn oil levels on colonic epithelial cell proliferation was assessed using [3H]thymidine incorporation assays. Cellular proliferation in the cecum, proximal colon and distal colon was not significantly higher when healthy rats consumed low fiber in comparison to high fiber diets, nor when healthy rats consumed high fat diets in comparison to low fat diets. Additionally, there were no significant interactions between these variables. In comparison to the low fiber diets, diets high in fiber caused a significantly lower pH of luminal contents of the cecum and distal colon, but there were no significant differences in the total short-chain fatty acid concentrations of cecal digesta. These results suggest that when energy intakes are equivalent among diets, low levels of fiber or high levels of fat in the diet do not cause biological changes in colonic mucosa that may be associated with increased risk of colonic cancer.

Volatile fatty acids: their production, absorption, utilization, and roles in human health.

The evidence shows that microbial fermentation of carbohydrates and endogenous substrates occurs in the large intestine of humans and that VFA represent a major endproduct. The large number of bacterial species, the complex nature of their interactions, and the endproducts of their fermentation processes are all likely to have significance in human health. Fermentation in the human intestine resembles rumen fermentation with respect to the metabolic pathways involved in anaerobic degradation of organic matter and in the concentrations of VFA endproducts. Thus, rumen bacteria are useful for understanding the dynamics and potential interactions of human intestinal bacteria. Current research is directed towards examining fermentation processes in animals, such as the pig and some species of monkey, since these animals most closely resemble the human. From such animal studies the metabolic activities of VFA and the processes by which they are produced and absorbed can be more clearly investigated and understood. The effects of diet on the microflora and on the metabolic pathways leading to the generation of VFA are under investigation. Modification of diet seems the most likely way of modifying the extent to which VFA are produced and absorbed by the human. As methodologies and protocols for evaluating human intestinal fermentation in vivo are revised and made more sensitive, the significance of fermentation will become more clearly understood. However, it appears that VFA make a physiologically significant contribution to the health of the colonic mucosa, and to the energy supply of the host. The magnitude of these effects is probably influenced by diet.

The TCA cycle as an oxidative and synthetic pathway is suppressed with aging in jejunal epithelial cells.

The influence of aging on glucose and glutamine metabolism by isolated jejunal cells was studied using young (4 months) and aged (24 months) Fischer 344 male rats when fed ad libitum or fasted 48 h. Concentration-dependent oxidation of glucose ([14C(U)]glucose) followed Michaelis-Menten kinetics. Neither K(ox) nor Vmax was influenced by animal age or feeding status, but at 1 mM, glucose oxidation was significantly higher for aged than young fed animals. In all animal groups, glutamine reduced glucose oxidation by ca. 60%, glucose stimulated glutamine oxidation by ca. 25%, and succinate CO2 ratios ranged from 1.37 for 20 mM glucose to 5.46 for 20 mM glucose+glutamine. The probability that a substrate that enters the TCA cycle will either remain in the cycle for one complete turn or leave and reenter as acetyl-CoA averaged 0.85 for glucose, 0.36 for glutamine, and 0.31 for glucose+glutamine. In comparison with the young fed animals, cells from fed aged animals showed lower oxygen uptake in the absence and presence of exogenous substrate, lower glucose oxidation, lower entry of glucose and glutamine into the TCA cycle, and lower contribution of glucose and glutamine carbon to anaplerosis and subsequent synthetic compounds. Differences between the young and aged animals were more pronounced in cells from fed animals than from fasted animals.

Glycolysis is a source of pyruvate for transamination of glutamine amino nitrogen in jejunal epithelial cells.

Previous research has shown that glucose increases transamination of glutamine amino nitrogen with pyruvate. It is unclear whether glucose or glutamine provides the pyruvate used for transamination. In the current study, it was hypothesized that glucose provides pyruvate for transamination of glutamine amino nitrogen. This hypothesis was tested by tracing the metabolism of [2-(13)C]glucose in these cells incubated in the presence of [2-(13)C] glucose or [2-(13)C] glucose and glutamine using (13)C nuclear magnetic resonance. Glutamine supplementation increased alanine production but did not affect lactate production. The 1-(13)C, 2-(13)C, 3-(13)C, 1,2-(13)C, and 2,3-(13)C isotopomers of alanine and lactate were produced when glutamine was supplemented. Glutamine supplementation increased production of 2-(13)C, 1,2-(13)C, and 2,3-(13)C isotopomers of alanine but did not affect the production of isotopomers of lactate. The ratio of production of [2-(13)C]alanine to [3-(13)C]alanine was 37:1 when glutamine was present. The predominance of production of [2-(13)C]alanine vs. all other isotopomers demonstrates that a large proportion of the pyruvate used for transamination of glutamine amino nitrogen was derived from glycolysis.

Oxidation of glucose carbon entering the TCA cycle is reduced by glutamine in small intestine epithelial cells.

The influence of glutamine on glucose oxidation was assessed in epithelial cells isolated from the mucosa of the proximal, mid-, and distal small intestine of young, fed, male rats. Glucose oxidation declined along the length of the small intestine, with values from the mid- and distal segments representing approximately 55% and 40%, respectively, of the value from the proximal segment. A gradient along the small intestine was noted also in the influence of glutamine on glucose oxidation: glutamine suppressed glucose oxidation approximately 60% in the proximal small intestine, 39% in the mid-intestine, and 31% in the distal small intestine. Glutamine suppressed the oxidation of glucose carbon that entered the tricarboxylic acid (TCA) cycle; this was determined using CO2 ratios derived from acetate and glucose isotopes. In cells from the proximal segment, the probability that carbon entering the cycle would complete one full turn was reduced by glutamine from 0.77 to 0.28. The entry of glucose-derived pyruvate into the TCA cycle did not appear to be influenced by the presence of glutamine, however. Glutamine had no influence on the proportion of glucose metabolism that occurred via the pentose phosphate pathway (which averaged 5% or less), but reduced flux of carbon through pyruvate carboxylase relative to flux through pyruvate dehydrogenase from 40% to 9% in cells from the proximal segment. These data suggest that, in the presence of glutamine, the fate of pyruvate carbon (derived from glucose or elsewhere) entering the TCA cycle is altered from that of oxidation to anaplerosis and subsequent efflux of TCA cycle intermediates into newly synthesized compounds.