Disorders of prosencephalic development

Abnormal ventral induction may result in disorders of formation, cleavage, and midline development of prosencephalic structures. Holoprosencephaly is a developmental field defect of impaired cleavage of prosencephalon. The most widely accepted classification of holoprosencephaly recognizes three major varieties: the alobar, semilobar and lobar types, according to the severity of the malformation. The brain malformations, characterized by the fusion of the cerebral hemisphere along the midline are commonly associated with facial anomalies. Corpus callosum agenesis and septo-optic dysplasia are disorders of prosencephalic midline development, and usually have less severe presentations but still, affected subjects may suffer from neurodevelopmental retardation, and/or endocrinologic and visual disorders. In this article we report an up-to-date of pathogenesis, prenatal sonographic findings, differential diagnosis and prognosis of the aforementioned anomalies. Copyright © 2009 John Wiley & Sons, Ltd.     

Fenton's pre-treatment of mature landfill leachate

The aim of this study was to check the effectiveness of the Fenton's reagent (Fe2+ + H2O2 + H+) for the pre-treatment of a municipal landfill leachate with the objective of improving its overall biodegradability, evaluated in terms of BOD5/COD ratio, up to a value compatible with biological treatment. The leachate came from a municipal sanitary landfill located in southern Italy and the average values of its main parameters were: pH=8.2; COD=10,540 mgl(-1); BOD5=2,300 mgl(-1); TOC=3,900 mgl(-1); NH4-N=5210 mgl(-1); conductivity=45,350 microScm(-1); alkalinity=21,470 mgl(-1) CaCO3. The effect of initial pH value on the pre-treatment effectiveness was evaluated by titrating the amount of acidic by-products formed. The extent of leachate oxidation was monitored and controlled by both pH and redox potential measurements. The best operational conditions for achieving the desired goal (i.e., BOD5/COD> or =0.5) resulted: Fe2+=275 mgl(-1); H2O2=3,300 mgl(-1); initial pH=3; reaction time=2 h. At the end of the Fenton's pre-treatment, in order to permit a subsequent biological treatment, residual ferric ions were removed increasing the pH up to 8.5 by adding 3 gl(-1) of Ca(OH)2 and 3 mgl(-1) of a cationic polyelectrolyte, the latter as an aid to coagulation. This final step also resulted in a further modest removal of residual COD due to co-precipitation phenomena.     

Interrupted aortic arch type A with 22q11 deletion: prenatal detection of an unusual association

Interrupted aortic arch is a rare, severe congenital heart defect subdivided into three types, A, B and C, according to the site of interruption. Type C is by far the least common form of interrupted aortic arch (less than 5% of cases), type A is commonly an isolated defect whereas type B is frequently associated with 22q11 deletion. Differentiation of interrupted aortic arch type A from type B by prenatal echocardiography is possible but difficult; it needs to be done on the basis of observation of reliable morphological indicators which point to the correct diagnosis. Here we report the first case of prenatal diagnosis of interrupted aortic arch type A associated with 22q11 deletion. The significance of this association is not yet clear, since 22q11 genes mainly affect embryonic cardiovascular morphogenesis of those regions whose development is critically dependent on neural crest cell migration and function, affected in type B defect but not in type A. Copyright © 2002 John Wiley & Sons, Ltd.     

Genome Stability vs. Deprivation or Enrichment of the Geomagnetic Field

Summary This study suggested that cell-cycle kinetics, DNA replication and DNA repair react to magnetic fields differently. During their culture growth cycle, which lasted about five days, Friend erythroleukemia cells were either kept in the absence of magnetic fields in a magnetically shielded room or irradiated in a solenoid with 70 μT at 50 Hz plus 45 μT DC of the Earth: some cells grew without inducer of in vitro differentiation; others were induced to differentiate hemoglobin through dimethylsulfoxide. It emerged that, during a single culture growth cycle, while proliferation was slightly accelerated by the magnetic-field irradiation achieved in the solenoid both in undifferentiating and dimethylsulfoxide-differentiating cells, DNA replication did not appear to significantly depend on the magnetic-field deprivation achieved in the magnetically shielded room. However, as a result of a 318-day long magnetic-field irradiation in the solenoid, DNA replication remained unchanged in undifferentiating cells and partially inhibited in dimethylsulfoxide-differentiating cells. Following the same long magnetic-field irradiation in the solenoid, the amount of labelled repair patches in the parental DNA strands was slightly reduced.