Noninvasive biomarkers for the diagnosis of steatohepatitis and advanced fibrosis in NAFLD.

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of abnormal liver enzymes in both adults and children. NAFLD has a histologic spectrum ranging from simple steatosis to nonalcoholic steatohepatitis (NASH), advanced fibrosis, and cirrhosis. It is imperative to distinguish simple steatosis from NASH since the latter has a progressive disease course and can lead to end-stage liver disease. Liver biopsy has been considered as the gold standard for the diagnosis of NASH. However, liver biopsy is invasive, costly, and can rarely cause significant morbidity (risk of morbidity, 0.06-0.35%; risk of mortality, 0.1-0.01%). Imaging studies such as ultrasonography, computed tomography, and magnetic resonance imaging have limited sensitivity in detecting steatosis and cannot distinguish steatosis from NASH. Alanine aminotransferase (ALT) has been used as a surrogate marker for liver injuries. However, ALT is not an ideal marker for either diagnosis of NAFLD or distinguishing steatosis from NASH. Better noninvasive biomarkers or panels of biomarkers that are cheaper, reliable, and reproducible are urgently needed for patients with NASH to assist in establishing diagnosis, providing risk information, and monitoring disease progression and treatment response. In this article, we plan to concisely review the current advances in the use of biomarkers for the diagnosis of NASH.

Exposure to community violence and protective and risky contexts among low income urban African American adolescents: a prospective study.

This study examined protective and risky companionship and locations for exposure to community violence among African American young adolescents living in high crime, urban areas. The Experience Sampling Method (ESM), an in vivo data collection method, was employed to gather information from 233 students (62% female) over 3 years, beginning in the 6th grade. Questionnaire variables of exposure to community violence were regressed onto ESM companionship and location variables, cross-sectionally and longitudinally, separately for boys and girls. At different points, time spent with parents, in school, and outside in private space was associated with less exposure to violence for boys and girls, while time spent with girls was protective for boys. In addition, time spent outside in public and with older peers was associated with increased risk for boys and girls. These findings are discussed in relation to previous and potential future research, and to strategies to prevent exposure to community violence.

Validation of Cosmed's FitMate in measuring exercise metabolism.

The purpose of this study was to assess the validity of the FitMate metabolic system (Cosmed, Rome, Italy) in measuring oxygen consumption during graded exercise. The FitMate is a new, small (20 x 24 cm) metabolic analyzer designed for measurement of oxygen consumption during rest and exercise. Subjects included 40 healthy adults (N = 20 males, N = 20 females) ranging in age from 18 to 37 kg/m2 (mean +/- SD age, 22.5 +/- 3.6 years) and body mass index (BMI) from 18.3 to 32.5 kg/m2 (23.2 +/- 3.3 years). One-minute FitMate and Douglas bag measurements were made during steady state conditions at the end of each 3-minute stage of the Bruce treadmill graded exercise test, and subjects continued until they could not attain steady state exercise during a stage. Oxygen consumption difference scores (Douglas bag minus FitMate measurements) did not differ between males and females, so data were combined and analyzed for the entire group. During the first three stages, mean oxygen consumption did not differ significantly between the Douglas bag and FitMate systems (26.5 +/- 1.1 and 26.7 +/- 1.3 ml.kg-1.min-1, respectively, P = 0.140) with a mean absolute difference of 0.23 +/- 0.91 ml.kg-1.min-1 or 14.2 +/- 67.5 ml.min-1. In conclusion, the FitMate metabolic system accurately measures oxygen consumption during graded treadmill exercise when compared with the Douglas bag system in male and female adults.

Influence of carbohydrate on immune function following 2 h cycling.

The influence of carbohydrate compared with placebo ingestion on changes in immune cell counts and functions following 2 h intensive cycling was studied in 12 trained cyclists who functioned as their own controls. The subjects performed two tests 2 weeks apart where they cycled for 2 h at approximately 64% Watts(max) while receiving 4 mL x kg(-1) x 15 min(-1) carbohydrate (6%) (Cho) or placebo (Pla) beverages. Blood samples were collected 30 min preexercise, and immediately and 1 h postexercise. The samples were assayed for plasma cortisol and epinephrine, blood leukocyte subset counts, PHA-induced lymphocyte proliferation, and natural killer cell activity (NKCA). Compared with Pla ingestion, Cho attenuated exercise-induced changes in plasma cortisol, blood neutrophil, and monocyte counts, but not in total blood lymphocyte, T cell, and NK cell counts, PHA-induced lymphocyte proliferation, and NKCA. Thus despite a strong attenuating influence of carbohydrate ingestion on exercise-induced changes in plasma cortisol and blood neutrophil and monocyte counts, other immune measures related to lymphocyte subset counts, and function were unaffected.

Blood leukocyte mRNA expression for IL-10, IL-1Ra, and IL-8, but not IL-6, increases after exercise.

The primary purpose of this project was to study exercise-induced leukocyte cytokine mRNA expression. Changes in plasma cytokine levels and blood leukocyte mRNA expression for interleukin-6 (IL-6), IL-8, IL- 10, and IL-1 receptor antagonist (IL-1Ra) were measured in 12 athletes following 2 h of intensive cycling ( approximately 64% Watts(max)) while ingesting a carbohydrate or placebo beverage (randomized and double blinded). Blood samples were collected 30 min preexercise and immediately and 1 h postexercise. Carbohydate compared with placebo ingestion attenuated exercise-induced changes in plasma cortisol (8.8% vs. 62%, respectively), epinephrine (-9.2% vs. 138%), IL-6 (10-fold vs. 40-fold), IL-10 (8.9-fold vs. 26-fold, and IL-1Ra (2.1-fold vs. 5.6-fold). Significant time effects were measured for blood leukocyte IL-8 (2.4-fold increase 1 h postexercise), IL-10 (2.7-fold increase), IL-1Ra (2.2-fold increase), and IL-6 (0.8-fold decrease) mRNA content, with no significant differences between Cho and Pla test conditions. In summary, gene expression for IL-8, IL-10, and IL-1Ra, but not IL-6, is increased in blood leukocytes taken from athletes following 2 h of intensive cycling and is not influenced by carbohydrate compared with placebo ingestion. mRNA expression was high enough to indicate a substantial contribution of blood leukocytes to plasma levels of IL-8, IL-10, and IL-1Ra during prolonged exercise.

Validation of Cosmed's FitMate in measuring oxygen consumption and estimating resting metabolic rate.

The purpose of this study was to assess the validity and reliability of the FitMate metabolic system (Cosmed, Rome, Italy) in measuring oxygen consumption and estimating resting metabolic rate (RMR). The FitMate is a new, small (20 x 24 cm) metabolic analyzer designed for measurement of oxygen consumption and energy expenditure during rest and exercise. Subjects included 60 healthy adults (N = 30 males, N = 30 females) ranging in age from 19 to 65 years (mean +/- SD age, 36.9 +/- 13.4 years) and body mass index (BMI) from 19.2 to 44.8 kg/m2 (27.7 +/- 6.2 kg/m2). Subjects were given two 10 min RMR tests in one test session during which RMR was measured simultaneously with the Douglas bag and FitMate systems. No significant differences were found between Douglas bag and FitMate systems for oxygen consumption (242 +/- 49 and 240 +/- 49 ml/min, respectively, P = 0.066, r = 0.97, mean +/- SD absolute difference 2.83 +/- 11.68 ml/min) or RMR (1,662 +/- 340 and 1,668 +/- 344 kcal/day, P = 0.579, r = 0.97, mean +/- SD absolute difference 5.81 +/- 80.70 kcal/day). These data indicate that the FitMate is a reliable and valid system for measuring oxygen consumption and RMR in adults.