Simultaneous determination of fecal fat, nitrogen, and water by near-infrared reflectance spectroscopy

Sex Differences of Kidney Stone Urine Risk Factors after Roux-en-Y Gastric Bypass

INTRODUCTION

Roux-en-Y gastric bypass (RYGB) is a bariatric surgical procedure that is associated with higher risk of kidney stones after surgery. We examined urine composition in 18 men and women before and after RYGB to examine differences in kidney stone risk.

METHODS

Three 24-h urine collections were performed before and 1 year after RYGB. We analyzed mean urinary values for pre- and post-RYGB collections and compared men and women.

RESULTS

Seven men and eleven women completed pre- and post-RYGB urine collections. Pre-RYGB, men had higher calcium oxalate supersaturation (CaOx SS) (7.0 vs. 5.0, p = 0.04) compared with women. Post-RYGB, women had higher urine CaOx SS (13.1 vs. 4.6, p = 0.002), calcium phosphate supersaturation (1.04 vs. 0.59, p = 0.05), and lower urine volumes (1.7 vs. 2.7L, p < 0.001) compared with men.

DISCUSSION/CONCLUSION

There are important differences in urine composition by sex that may contribute to higher kidney stone risk in women after RYGB compared with men.

The application of near infrared spectroscopy to predict faecal nitrogen and phosphorus in multiple ruminant herbivore species

Near infrared spectroscopy (NIRS) was applied to determine faecal nitrogen and phosphorus using a temporo-spatially diverse dataset derived from multiple ruminant herbivore species (i.e. cattle, bison, deer, elk, goats, and sheep). Single-species NIRS calibrations have previously been developed to predict faecal constituents. Multi-species NIRS calibrations have previously been developed for herbivore faecal nitrogen but not for faecal phosphorus. Faecal samples representing a herd or flock composite were analysed via NIRS (400–2498nm). Calibration sets for faecal nitrogen and phosphorus were developed from: (1) all samples from all six species, (2) all cattle samples only, (3) all samples except those from bison, (4) all samples except those from deer, (5) all samples except those from elk, (6) all samples except those from goats, and (7) all samples except those from sheep. Validation sample sets included: (1) each of the individual species (predicted with a cattle only-derived calibration), and (2) each of the individual species (other than cattle) predicted with a multi-species calibration constructed from all cattle samples plus those samples from the remaining four species (i.e. ‘leave-one-out’). All multiple coefficient of determination (R2) values for faecal nitrogen calibrations were ≥0.97. Corresponding standard error of cross validation (SECV) values were ≤0.13. Validation simple coefficient of determination (r2) and standard error of prediction (SEP) of each alternate species using the cattle-derived calibration ranged from 0.76 to 0.84, and 0.28 to 0.5 respectively. Similar values for the sequential species leave-one-out validation for faecal nitrogen were 0.67 to 0.89, and 0.17 to 0.47 respectively. All R2 values for faecal phosphorus calibrations were ≥0.79; corresponding SECV were ≤0.14. Validation r2 and SEP of each alternate species using the cattle-derived phosphorus calibration were ≤0.63 and ≥0.13 respectively. Similar values for the sequential species leave-one-out validation were ≤0.66 and ≥0.22 respectively for faecal phosphorus. Multi-species faecal NIRS calibrations can be developed for monitoring applications in which determination of faecal nitrogen is appropriate, e.g. free-ranging herbivore nutrition, nitrogen deposition from animal faeces on rangelands with declining forage quality, or runoff from confined animal feeding operations. Similar calibrations for faecal phosphorus require additional research to ascertain their applicability.

The importance of stool tests in diagnosis and follow-up of gastrointestinal disorders in children

Stool is not just a simple waste material. Some stool tests can be easily used in primary care in the differential diagnosis of disorders such as gastrointestinal infections, malabsorption syndromes, and inflammatory bowel diseases. Stool tests can prevent unnecessary laboratory investigations. Stool analyses include microscopic examination, chemical, immunologic, and microbiologic tests. Stool samples can be examined for leukocytes, occult blood, fat, sugars (reducing substances), pH, pancreatic enzymes, alpha-1 antitrypsin, calprotectin, and infectious causes (bacteria, viruses, and parasites). Stool should also be macroscopically checked in terms of color, consistency, quantity, shape, odor, and mucus.

Intrahepatic triglyceride measurement and estimation of viability in rat fatty livers by near-infrared spectroscopy

AIM

This study investigated the features of fatty livers using near-infrared (NIR) spectroscopy and validated the usefulness of NIR spectroscopy for the measurement of intrahepatic triglyceride (TG) contents and evaluation of viability in fatty livers.

METHODS

In vitro, we examined specific spectra for each purified TG fraction by NIR. In vivo, the differences between the spectra obtained from normal and fatty livers before warm ischemia and the differences between the spectra obtained from each rat liver before and after warm ischemia were subjected to multicomponent analysis.

RESULTS

In vitro experiments revealed a specific peak at 925 nm in major TG fractions, and NIR spectroscopy precisely detected changes in TG volume. In vivo experiments revealed that NIR spectroscopy detected TG content changes in rat fatty livers induced by a choline-deficient diet following the addition of purified TG spectrum for NIR spectroscopic analysis in least square curve fitting. The TG level in the fatty livers measured by NIR spectroscopy significantly correlated with the morphometric measurement of lipid content in the livers. NIR spectroscopy also revealed decreased levels of total hemoglobin (Hb) and oxidized Hb and maintenance of homeostasis in cytochrome redox states in fatty livers under normal condition. However, NIR spectroscopy showed irreversible deterioration of hepatic microcirculation, Hb oxygenation and homeostasis of the cytochrome redox states in fatty livers after 60-min warm ischemia reperfusion.

CONCLUSION

These studies demonstrated that NIR spectroscopy can quantitatively measure the intrahepatic TG content in addition to simultaneously evaluating microcirculation and Hb oxygenation.

Modification of stool's water content in constipated infants: management with an adapted infant formula

Background

Constipation is a common occurrence in formula-fed infants. The aim of this preliminary study was to evaluate the impact of a formula with high levels of lactose and magnesium, in compliance with the official regulations, on stool water content, as well as a parental assessment of constipation.

Materials and methods

Thirty healthy term-born, formula-fed infants, aged 4-10 weeks, with functional constipation were included. All infants were full-term and fed standard formula. Exclusion criteria were preterm and/or low birth weight, organic constipation, being breast fed or fed a formula specially designed to treat constipation. Stool composition was measured by near-infrared reflectance analysis (NIRA) and parents answered questions about crying associated with defecation and stool consistency at baseline and after two weeks of the adapted formula.

Results

After 2 weeks of the adapted formula, stool water content increased from 71 +/- 8.1% to 84 +/- 5.9%, (p < 0.02). There was no significant change in the stool's fat, protein or carbohydrate content. Parental impressions of constipation were improved with the decrease in stool hardness (100% with hard stools at baseline, 10% after 2 weeks), pain with defecation (90% at baseline, 10% after 2 weeks), and the requirement for rectal stimulation to achieve defecation (70% at baseline, 30% after 2 weeks, p < 0.001 for all three indicators).

Conclusions

This preliminary study suggests that an adapted formula with high levels of lactose and magnesium increases stool water content and improves symptoms of constipation in term-born, formula-fed infants. A larger randomized placebo-controlled trial is indicated.

Lack of correlation between fecal elastase-1 levels and fecal nitrogen excretion in preterm infants

We measured fecal elastase-1 (FE1) levels in 34 preterm newborns (15 small-for-gestational-age and 19 appropriate-for-gestational-age) during the first 2 months of life and evaluated whether they were correlated with nitrogen loss in stools. FE1 increased over time, and values were similar in both groups of newborns. Fecal nitrogen was significantly higher in small-for-gestational-age infants. There was no correlation between FE1 levels and fecal nitrogen excretion. Pancreatic proteolytic function was efficient at an early stage in enterally fed preterm newborns. Despite the similar FE1 values, fecal nitrogen loss was significantly higher in small-for-gestational-age preterm infants than in appropriate-for-gestational-age preterm infants.