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Objective Our objective was to investigate the relation between the embryological development and neural tissue maturation at the site where the neural plate failed to form a neural tube. Material and methods Samples from 15 aborted human fetuses with neural tube defects (NTD). All of the fetuses were between 20 and 25 gestational weeks old. Indicators of neural tissue maturation, formation of basal lamina, expression of integrins and neuron specific class III beta tubulin (tuj1) were investigated. To detect the adverse effects of the environment, if any, p53 and bcl-2 activity at both sites of the open and closed neural plate were investigated as well. Results No difference was found in the expression of maturation-related molecules at the site of the neural plate that remained open compared with the site where the neural tube is normally formed. While high p53 activity was noted in neural tissue at the site of the neural tube defect, no such activity was detected in the neural tissue where the neural tube is normally formed. Conclusion Our results suggested that maturation and differentiation of neural tissue continued regardless of the failure of neural tube closure. Therefore, the neurological deficits that are encountered in NTD patients should be related to secondary damage such as amnion fluid toxicity, uterus contractions, labor, etc. It seems valuable to save the neural plate before the negative effects of the environment renders the neural tissue functionless.

Abstract Introduction. Tethered spinal cord is defined as a condition in which the conus medullaris ends at a level below the L1-2 intervertebral space. The spinal cord is considered to be tethered when there is a thick filum terminale or low-lying conus medullaris. It has also been reported that a normal level of the conus medullaris and normal thickness of the filum terminale do not mean that there is no cord tethering. Materials and methods. In this investigation, we examined 21 fila terminalia; 5 of them were taken from cadavers, and these were used as a control group (group 1; n/n), 8 from patients with a normal appearance of the filum terminale but with clinical symptoms (incontinence) and pathologic results of a urodynamic study (group 2; n/ab), and 8 from patients with an abnormal appearance of the filum terminale and with clinical symptoms (group 3; ab/ab). Interestingly, we found that while fila terminalia in the control group were made up mainly of collagen fibers, more connective tissue with dense collagen fibers, some hyalinization and dilated capillaries were noticed in the fila from group 2. Results. Our results suggest that these histological features may reflect a decreased elasticity within the filum terminale, resulting in a tethering effect on the lower conus in otherwise normal physiological conditions. Conclusion. These findings lead us to reconsider sectioning of the filum terminale in incontinent patients with normal results in radiological studies, whose condition is called "nonneurogenic neurogenic bladder."