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PubMed1976

[Experimental studies on the etiological mechanism of congenital microcephaly].

Pregnant mice were injected intraperitoneally on different gestational day with either one or three successive doses of 30 mg/kg of cytosine arabinoside (ara-C), which has been known to interfere with DNA synthesis. Some of them were injected intraperitoneally with tritiated thymidine (3H-TdR) consecutively. The fetuses and the youngs were sacrificed at various hours and days after treatment. Pyknotic nuclei or nuclear debris were observed at the matrix layer three hours after the injection of single dose of ara-C. Nuclear debris were increased as time elapse and they were most prominent 12 hours after treatment. However, 24 hours later, new matrix layer was regenerating. Twenty-four hours after treatment with two successive doses of ara-C, labeling index in the matrix layer was about one third of that of control. Cerebral hemispheres of the treated youngs were reduced in size. The youngs, treated with three successive doses of ara-C on day 13, 14 and 15 of gestation, showed most severe microcephalus. Cytoarchitecture in the cortices of these microcephalic mice was characterized by irregular arrangement of the pyramidal neurons and their dendritic branches. Autoradiographic study revealed that cortical neurons which were produced at the regenerated matrix layer after ara-C treatment migrated to the surface of the cortex.

Animals↗
PubMed2000

[Adult Hirschsprung's disease with mental retardation and microcephaly].

Hirschsprung's disease occurs rarely and sporadically in adult, involving males. In cases, which are manifested perinatally, the so called Hirschsprung-associated congenital anomalies (mainly central nervous system, urogenital and cardiovascular) may present (2-21%), which have not observed in adult. Mental retardation and Hirschsprung's disease more frequently are associated with Down syndrome (5-10%). The discoveries of molecular genetics in the last 4-5-years through the examination of transgenic ("knockout") mice, proved the basic role the mutation of 4 genes: the RET (receptor tyrosin kinase), a proto-oncogene, coding its ligand, the glial cell-line derived neutrophic factor (GDNF), the gene of the endothelin-B receptor (ENDRB) and the gene one of its ligand, the endothelin-3 (EDN3), in the pathogenesis of Hirschsprung's disease. In our case, the short segment Hirschsprung's disease caused respiratory and cardiac failure, which was recognized by autopsy. Besides, the severe mental retardation, the role of the long term use of antipsychotic medicines comes up in the prolongation and masking of the symptoms. The accompanied mental retardation and microcephalia in early childhood are known, which are associated anomalies with Hirschsprung's disease. In cases of Hirschsprung diseases at adults, no other associated congenital anomalies has been published. The mental retardation in Down-syndrome, in association with Hirschsprung's disease (and presumable in our case, too) is supposed to be the consequence of the mutation in the gene of GDNF. In this case, we observed, that the so called short segment H-d was accompanied at a 33 years old men patient with mental retardation (who was originated from a gypsy ethnic minority), because of it the connection of the nurses and the patient was disturbed and the main symptom of the H-d (chronic obstipation) remained hidden. The mechanic ileus was going on behind the scenes, and in addition to the cardiac failure caused the death of the patient. Practical conclusion of the case is that, Hirschsprung's disease should be suspected in all adult patients, who had severe obstipation persisting since childhood, especially in males.

Adult↗