Stability of and change in substance use risk personality: Gender differences and smoking cigarettes among early adolescents.

OBJECTIVE: Adolescents show a steadily increasing inclination toward health risk behaviors, including smoking cigarettes. There is ample evidence that personality traits are related to smoking behavior. However, less is known about the stability of and change in these personality traits during early adolescence and whether smoking behavior affects the developmental trajectories. Moreover, less is known about the influence of gender on the course of personality. METHOD: Longitudinal data of three waves were used from 1121 early adolescents. To measure personality, the Substance Use Risk Profile Scale was used. Individual growth curve models were conducted to measure the stability, mean-level change and individual differences in change for personality. RESULTS: Stability of personality was moderate for boys and ranged from moderate to high for girls. On average early adolescents became more impulsive and more sensation seeking over a period of 18 months. Furthermore, hopelessness for girls increased and the increase in sensation seeking was higher for girls than for boys. Third, smoking behavior was related to all personality traits, indicating that smoking adolescents are more anxious, hopeless, impulsive and sensation seeking than non-smoking adolescents. CONCLUSIONS: Our results are in line with the disruption hypothesis, i.e., during early adolescence there is a dip in personality maturity. There are clear differences between girls and boys in stability of and change in personality traits. Besides, although smoking behavior is related to personality, the change in personality is probably related to other variables.

White matter changes in the perforant path area in patients with amyotrophic lateral sclerosis.

OBJECTIVE: The aim of this study was to test the hypothesis that white matter degeneration of the perforant path - as part of the Papez circuit - is a key feature of amyotrophic lateral sclerosis (ALS), even in the absence of frontotemporal dementia (FTD) or deposition of pTDP-43 inclusions in hippocampal granule cells. METHODS: We used diffusion Magnetic Resonance Imaging (dMRI), polarized light imaging (PLI) and immunohistochemical analysis of post mortem hippocampus specimens from controls (n = 5) and ALS patients (n = 14) to study white matter degeneration in the perforant path. RESULTS: diffusion Magnetic Resonance Imaging demonstrated a decrease in fractional anisotropy (P = 0.01) and an increase in mean diffusivity (P = 0.01) in the perforant path in ALS compared to controls. PLI-myelin density was lower in ALS (P = 0.05) and correlated with fractional anisotropy (r = 0.52, P = 0.03). These results were confirmed by immunohistochemistry; both myelin (proteolipid protein, P = 0.03) and neurofilaments (SMI-312, P = 0.02) were lower in ALS. Two out of the fourteen ALS cases showed pTDP-43 pathology in the dentate gyrus, but with comparable myelination levels in the perforant path to other ALS cases. CONCLUSION: We conclude that degeneration of the perforant path occurs in ALS patients and that this may occur before, or independent of, pTDP-43 aggregation in the dentate gyrus of the hippocampus. Future research should focus on correlating the degree of cognitive decline to the amount of white matter atrophy in the perforant path.

Acrylamide exposure from foods of the Dutch population and an assessment of the consequent risks.

At the end of April 2002, the Swedish Food Administration reported the presence of acrylamide in heat treated food products. Acrylamide has been shown to be toxic and carcinogenic in animals, and has been classified by the WHO/IARC among others as 'probably carcinogenic for humans'. The purposes of this study were firstly to analyse acrylamide contents of the most important foods contributing to such exposure, secondly, to estimate the acrylamide exposure in a representative sample of the Dutch population, and thirdly to estimate the public health risks of this consumption. We analysed the acrylamide content of foods with an LC-MS-MS method. The results were then used to estimate the acrylamide exposure of consumers who participated in the National Food Consumption Survey (NFCS) in 1998 (n=6250). The exposure was estimated using the probabilistic approach for the total Dutch population and several age groups. For 344 food products, acrylamide amounts ranged from <30 to 3100 microg/kg. Foods with the highest mean acrylamide amounts were potato crisps (1249 microg/kg), chips (deep-fried) (351 microg/kg), cocktail snacks (1060 microg/kg), and gingerbread (890 microg/kg). The mean acrylamide exposure of the NFCS participants was 0.48 microg/kg bw/day. Risk of neurotoxicity is negligible. From exposure estimations it appears that the additional cancer risk might not be negligible.

[The reliability of vaginal cytology in determining the optimal mating time in the bitch]. / De betrouwbaarheid van vaginacytologie bij het bepalen van het optimale dektijdstip bij de teef.

The reliability of vaginal cytology for determining the optimal mating period is controversial. The importance of the site for obtaining the smear (the vestibule or the vagina) and the best staining method are also unclear. Therefore, we investigated the reliability of vaginal cytology as compared to plasma progesterone concentrations for determining the optimal mating period. Additionally, the influence of different locations for obtaining the smears and of the staining methods, i.e. May-Grünwald-Giemsa or Papanicolaou, a method that stains keratin in superficial cells, was examined. In total, the vaginal cytology of 35 bitches during the follicular phase was examined three times a week, until the optimal time for mating was established, based on plasma progesterone concentrations measured with a 125Iodine radio-immunoassay. The results indicate that vaginal cytology is not useful for determining the optimal mating period in bitches, since mating according to cytological findings would have resulted in only 28% of the bitches being mated at the proper time. The site for obtaining the smear and the staining method did not affect accuracy. It is therefore concluded that cytology is not useful in breeding management to determine the optimal mating period. It can be used, however, to determine the stage of the cycle in general, e.g. the early part of the follicular phase or the metoestrus and the detection of disorders in the follicular phase. For this purpose, a smear from the vestibule, stained with a morphological staining method, provides sufficient information.

Optimization of the postcolumn hydrolysis reaction on solid phases for the routine high-performance liquid chromatographic determination of N-methylcarbamate pesticides in food products.

Various solid-phase materials were evaluated as catalysts for the postcolumn hydrolysis of N-methylcarbamate pesticides in a high-performance liquid chromatographic (HPLC) method for food products. Inexpensive magnesium oxide has been used for the first time in HPLC as a very efficient catalyst and as a good alternative for, e.g., expensive anion-exchange resins. The reaction mechanism and kinetics were studied through measurement of the reaction band broadening, which depends on the stationary phase, mobile phase composition and flow-rate, and reaction temperature. Also, relationships between carbamate structure and reactivity were examined. The usefulness of the optimized postcolumn system was thoroughly tested by application to crop sample analysis during an extended period of time. The range of application of the solid-phase reaction was extended to 22 carbamate pesticides and ten of their metabolites. For crop sample analysis, limits of determination in the range 1-10 ppb were obtained.