Foramen magnum morphometry in children based on computed tomography examination.

BACKGROUND: The foramen magnum is the largest opening at the base of the skull. The dimensions of the foramen magnum are of significant clinical importance because of the vital structures that pass through it. The aim of the study was the morphometric analysis of the foramen magnum in children based on head computed tomography (CT). MATERIALS AND METHODS: The study was carried out on 84 CTs of the head of children aged 0-18 years; seven age groups were distinguished. The sagittal and transverse dimensions were measured to determine the growth rate, changes between groups, and differences in the foramen size by sex. Statistical analysis of changes was performed. RESULTS: The entire group's mean transverse and sagittal dimensions were 29.08 mm (standard deviation [SD] 3.4 mm) and 35.63 (SD 4.23) mm. By sex, the mean transverse dimension in girls was 28.53 (SD 3.25) mm, and in boys, 29.6 (SD 3.49) mm. The mean sagittal dimension was 35.15 (SD 3.76) mm in girls and 36.09 (SD 4.64) mm in boys. Both dimensions were higher for the male sex. A statistically significant increase in the foramen magnum size was demonstrated up to the age of 36 months in the following age groups; above that age, the increase was statistically insignificant. CONCLUSIONS: The dimensions were similar to those described in adults a moderate dependence of the foramen magnum size on age was found.

Differential hydration of dA.dT base pairing and dA and dT bulges in deoxyoligonucleotides.

The role of water in the formation of stable duplexes of nucleic acids is being studied by determining the concurrent volume change, heats, and counterion uptake that accompany the duplexation process. The variability of the volume contraction that we have observed in the formation of a variety of homoduplexes suggests that sequence and conformation acutely affect the degree of hydration. We have used a combination of densimetric and calorimetric techniques to measure the change in volume and enthalpy resulting from the mixing of two complementary strands to form (a) fully paired duplexes with 10 or 11 base pairs and (b) bulged decameric duplexes with an extra dA or dT unmatched residue. We also monitored absorbance vs temperature profiles as a function of strand and salt concentration for all four duplexes. Relative to the decamer duplex, insertion of an extra dA.dT base pair to form an undecamer duplex results in a favorable enthalpy of -5.6 kcal/mol that is nearly compensated by an unfavorable entropy term of -5.1 kcal/mol. This enthalpy difference correlates with a differential uptake of water molecules, corresponding to an additional hydration of 16 mol of water molecules/mol of base pair. Relative to the fully paired duplexes, both bulged duplexes are 12-16 degrees C less stable and exhibit marginally larger counterion uptake on forming the duplex. The enthalpy change is slightly lower for the T-bulge duplex and less still for the A-bulge duplex. The volume change results indicate that an unmatched residue increases the amount of coulombic and/or structural hydration. The combined results strongly suggest that the destabilizing forces in bulged duplexes are partially compensated by an increase in hydration levels.

[Study of the degree of discrepancies between analytical and theoretical results of the evaluation of daily food rations]. / Badanie wielkosci odchylen wyników analitycznych od teoretycznych przy ocenie wartosci calodziennych racji pokarmowych.

Thirty-six daily food rations given as the basic diet to children in two paediatric hospitals in the City of Cracow were analysed. Using laboratory methods in these meals the contents were analysed of protein, fat and carbohydrates and the energy value was determined. Parallelly the theoretical values++ of these parameters were calculated using "Tables of Composition and Nutritional Value of Food Products". For the assessment of the differences between analytical and theoretical values the following were used: 1) deviations of the values obtained in analysis from the theoretical ones accepted as 100%, 2) indices of differences. The general characteristics of the results was determined by the arithmetical++ mean, standard deviation, variance coefficient and 95% confidence limits. The results shown in the study demonstrate that the lowest mean deviation from the theoretical values was found in the case of protein (1.1%) and energy value (12.5%) with the largest one for carbohydrates (38.9%).