Technical note: Characterization of ceramide in bovine lipoproteins.

The hepatic synthesis and export of ceramide is enhanced in diabetic monogastrics. Moreover, ceramide in lipoproteins can mediate the development of insulin resistance. We have previously demonstrated that circulating ceramide increases during the progression of insulin resistance in postpartum dairy cows. Considering that the origins of circulating ceramide required investigation, our objective was to develop a method to characterize the ceramide profile of lipoprotein fractions collected from dairy cows. Serum was collected from 4 nonpregnant and nonlactating Holstein dairy cows. Serum lipoproteins were isolated using size exclusion chromatography by fast protein liquid chromatography (SEC-FPLC). Measurement of triacylglycerol (TAG), phospholipid, total cholesterol, and protein was performed using standard colorimetry practices. Following lipid extraction, fractions were analyzed using electrospray ionization tandem mass spectrometry. Data were analyzed as repeated measures using a mixed model. Lipoprotein isolation using SEC-FPLC and subsequent colorimetric analyses confirmed the presence of 4 distinct fractions: TAG-rich, low density (LDL), and large (buoyant) and small (dense) high density lipoprotein (HDL) subclasses. As expected, the fraction representing mixed very low density lipoproteins and chylomicrons primarily contained TAG. Low density lipoprotein fractions were equally enriched with cholesterol and phospholipid. Buoyant HDL contained elevated levels of cholesterol, phospholipid, and protein. In contrast, the fraction containing dense HDL primarily contained protein. Our method revealed that LDL are enriched with ceramides. Ceramides were also compartmentalized to a lesser extent within both HDL subclasses and TAG-rich lipoproteins. Comparable to whole serum, C16:0-ceramide was the predominant ceramide quantified in all lipoprotein subclasses. Interestingly, the proportion of C24:0-ceramide to total ceramide was elevated in TAG-rich lipoproteins, relative to all other lipoprotein subclasses. We conclude that SEC-FPLC coupled with mass spectrometry is a means to quantify ceramides in lipoprotein fractions. Moreover, ceramides are enriched within bovine LDL, and lipoprotein ceramide profiles reflect levels observed in whole serum. Future investigation will need to determine the biological importance of lipoprotein ceramides with distinct C-chains at amide residues.

Prospective longitudinal associations between household smoke exposure in early childhood and antisocial behavior at age 12.

Young children exert little control over household tobacco smoke exposure, which is considered a developmental neurotoxicant. Using the Quebec Longitudinal Study birth cohort, we examine prospective associations between early childhood smoke exposure and later antisocial behavior. Parents of 1035 children reported on the presence of household smokers at seven follow-ups from ages 1.5 to 7.5. At age 12, children self-reported on five aspects of early antisocial dispositions. After adjusting for confounders, every standard deviation increase in household smoke exposure was prospectively associated with a 19% standard deviation unit increase in conduct problems (ß=0.07; 95% confidence interval [CI] from 0.04 to 0.09), a 11% standard deviation unit increase in proactive aggression (ß=0.04; 95% CI from 0.01 to 0.07), a 13% standard deviation unit increase in reactive aggression (ß=0.07; 95% CI from 0.03 to 0.12), a 14% standard deviation unit increase in school indiscipline (ß=0.13; 95% CI from 0.05 to 0.20), and a 10% standard deviation unit increase in dropout risk (ß=0.07; 95% CI from 0.01 to 0.12). These long-term findings warrant fostering parental awareness of developmental risks by policy-makers/health practitioners. School curricula can equally integrate these ideas into their curriculum.

Prospective associations between televiewing at toddlerhood and later self-reported social impairment at middle school in a Canadian longitudinal cohort born in 1997/1998.

BACKGROUND: Using a large Canadian population-based sample, this study aimed to verify whether televiewing in toddlerhood is prospectively associated with self-reported social impairment in middle school. METHOD: Participants are from a prospective-longitudinal birth cohort of 991 girls and 1006 boys from the Quebec Longitudinal Study of Child Development. Child self-reported ratings of relational difficulties at age 13 years were linearly regressed on parent-reported televiewing at age 2 years while adjusting for potential confounders. RESULTS: Every additional 1 h of early childhood television exposure corresponded to an 11% s.d. unit increase in self-reported peer victimization [unstandardized ß = 0.03, 95% confidence interval (CI) 0.02-0.04], a 10% s.d. unit increase in self-reported social isolation (unstandardized ß = 0.04, 95% CI 0.03-0.05), a 9% s.d. unit increase in self-reported proactive aggression (unstandardized ß = 0.02, 95% CI 0.01-0.03) and a 6% s.d. unit increase in self-reported antisocial behavior (unstandardized ß = 0.01, 95% CI 0.01-0.01) at age 13 years. These results are above and beyond pre-existing individual and family factors. CONCLUSIONS: Televiewing in toddlerhood was prospectively associated with experiencing victimization and social withdrawal from fellow students and engaging in antisocial behavior and proactive aggression toward fellow students at age 13 years. Adolescents who experience relational difficulties are at risk of long-term health problems (like depression and cardiometabolic disease) and socio-economic problems (like underachievement and unemployment). These relationships, observed more than a decade later, and independent of key potential confounders, suggest a need for better parental awareness of how young children invest their limited waking hours.

[Antidiabetic activity of Zizyphus mauritiana Lam (Rhamnaceae)]. / Etude de l'activité antidiabétique de Zizyphus mauritiana Lam (Rhamnaceae).

In traditonnal medicine, several plants were used in diabetes treatment. Among them, the aqueous extract from the leaves of Zizyphus mauritiana Lam (Rhamnaceae) was studied. The extract was administrated per os to Wistar rats made diabetics either temporarily by oral glucose tolerance test (first case) or definetely by subcutaneous injection of alloxan (second case). It was observed a striking decrease of the hyperglycemic arrow (p < 0.05) in the first case, with 300 mg/kg administrated 90 minutes before starting the test. In the second case, the results obtained with a dose of 300 mg/kg once or twice a day were identical as those with glibenclamide at 0.2 mg/kg per day. So, the antidiabetic activity of Zizyphus mauritiana Lam was experimentally born out but it has to be standardized for common use.