It is generally accepted that the permeability of the blood-brain barrier in the fetus is higher than in the adult, but its structural basis is still not well known. In this paper, an ultrastructural study was performed on the cerebral capillaries of human fetus aged from 5-9 months and some structural parameters were measured. The results were as follows: (1) the endothelial tight junctions were longer and tortuous, and the clefts within the junctions were found and did not show apparent change in all groups; (2) the plasmalemmal vesicles were larger in 5th month than in the 9th month, and the density of vesicles was low (

To investigate the role of Egr-1 in the carcinogcnestic process of hepatocellular carcinoma (H-CC). Methods Expression of Egr-1 gene in HCC tissues were detected by in situ hybridization and immunohistochemistry. Human breast andmouse liver and brain tissues were used for control. ResultsLittle or no Egr-1 transcription was detected both in HCC tissues and in their normal counterparts. High transcription of Egr-1 was detected in the LCD and atrophic-like liver plate of HCC tissues. Protein expression of Egr-1 gene was consistent with mRNA transcription. High expression of Egr-1 protein was also detected in normal breast and mouse brain tissues. ConclusionsLittle or no expression of Egr-1 may play a role in the deregulation of normal growth in the carcinogenestic process of HCC. The differences of Egr-1 expression among liver cells, breast epithelia and mouse brain tissues might be associated with their different ways of proliferation and differentiation in different cell types.

OBJECTIVESTo investigate telomerase activity in esophageal squamous cell carcinoma (SCC) and its preneoplasia lesions, and to study the relationships between telomerase activity and cancer differentiation, cancer invasiveness, and lymphatic metastasis.

METHODSTelomerase activity in esophageal SCC tissues, adjacent dysplasia tissues and normal epithelia from the surgical edge were assessed by microdissection-TRAP (telomeric repeat amplification protocol)-silver staining assay.

RESULTSTelomerase activity was detected in 37 (82.2%) of 45 esophageal tumors, 23 (79.3%) of 29 dysplasias, and 2 (5%) of 40 normal epithelia. There was a significant difference in activity between dysplasia and normal epithelium, as well as between tumor and normal epithelium. Twenty-six (92.9%) of 28 tumors with lymphatic metastasis had detectable telomerase activity compared to 11 (64.7%) of 17 non-lymphatic metastasis tumors. These relationships were statistically significant (P < 0.05), but the one between telomerase activity and tumor grade was not.

CONCLUSIONTelomerase activity was high both in esophageal SCC and their preneoplasia lesions. The telomerase activity in SCC tissue was related to lymphatic metastasis, but not to cancer differentiation.

Adult ; Aged ; Carcinoma, Squamous Cell ; enzymology ; pathology ; Cell Differentiation ; Dissection ; Esophageal Neoplasms ; enzymology ; pathology ; Female ; Humans ; Male ; Middle Aged ; Polymerase Chain Reaction ; Precancerous Conditions ; Repetitive Sequences, Nucleic Acid ; Telomerase ; genetics ; metabolism ; Telomere