ABSTRACT
Objective To observe the ultrastructure of blood-brain barrier in the nude mouse model of brain me-tastases from lung cancer by transmission electron microscopy using lanthanum nitrate tracing.Methods PC-9 cells (1 × 106/0.1 mL) in logarithmic phase were respectively injected into six nude mice ( model group) selected from eight nude mice randomly via the left ventricle, the other two mice without any treatment as the control group.The general status of the mice was observed after implantation.In the fourth week all the mice were sacrificed and brain tissue samples were taken and prepared for transmission electron microscopic observation using lanthanum nitrate tracing.besides, the lung and brain were removed and stained with HE to detect the presence of tumor metastasis.Results Mice in the model group began to lose weight almost simultaneously in the third week and became moribund slowly, and were all sacrificed at the fourth week when showing clear signs of cachexia.At autopsy, the thoraxes were clear, with normal lungs.Histology showed evidence of brain metastasis in all the six mice.The electron microscopy showed that lathanum nitrate tracer was escaped from the capillaries and diffusely or sparsely distributed in the brain tissues of the model group mice, however lathanum nitrate tracer was still confined in the capillary lumen in the mice of control group.Conclusions The diffuse lathanum nitrate tracer in the brain parenchymal tissue indicates the impairment of blood-brain barrier in the nude mouse model of lung cancer brain metastasis and the formation of these metastases is accompanied with the destruction of blood brain barrier.
ABSTRACT
Objective:To examine the surface of mineral trioxide aggr eg ate (MTA) when treated in different conditions in vitro. Method: Root blocks were prepared. MTA and other three dental materials (Dycal, Dyr act and amalgam) were respectively filled into the root canals of prepared root blocks. The roots with the materials were maintained in distilled water or simul ated body fluid (SBF) at 37 ℃ for 5 days. Scanning electron microscopy(SEM) and X-ray energy dispersive spectroscopy(EDS) were employed to investigate the mor phological changes and chemical components. Results:There was pr ecipitate of simple crystal units or crystalline structure in the MTA specimens. EDS showed one or two peaks corresponding to calcium or calcium and phosphorus. Conclusions:Apatite may produce and grew by MTA on its surface.
ABSTRACT
The changes in the germinal epithelium of 27 azoospermic patients were studied by light and electron microscope. And a brief clinical observation was also made. The results obtained were as follows, 1) The two thirds of 27 cases were in the age group of 26 to 35. Fifteen cases (55.6%) were in the 2nd to 5th year of their marriages. The tendency of decreasing in tuberculous disease, gonorrhea and mumps was observed in their past history. The average volume of seminal fluid was 2.4ml in amount 2) Light microscopically, spermatogenic arrest was found in 22 cases, and followed by germinal tell aplasia in 3 and hypospermatogenesis in 2. Fifteen of 22 cases of spermatogenic arrest were relatively advanced. Two of 3 cases of germinal cell aplaeia were found in the older age group of 35 to 40, and both of two cases of hypospermatogenesis in the younger age group of 21 to 25. 3) On electron microscopic observation in the hypospermatogenesis, increase in number and mild vacuolar dilatation of endoplasmic reticulum and increase in number of lysosomes in the spermatocytes, and deformities and swelling of acrosomes and vacuolization of nucleoplasm in the spermatocytes, but no significant changes were seen in the spermatogonia and the Sertoli cells. 4) In the spermatogenic arrest, severe degenerative changes such as condensation of chromatin, occurrence of electron dense round bodies, and inapparent cell organells were observed in the spermatocytes. Mild to moderate degenerative changes such as increase in number and dilatation of endoplasmic reticulum, deformities, swelling or atrophy. and decrease in number of cristae of mitochondria were seen in the spermstogonia and the Sertoli cells 5) In the germinal cell aplasia, progressive and degenerative changes such as marked increase in number. vacuolar dilatation, and irregular arrangement of endoplasmic reticulum. marked deformities. swelling, vacuolization, and loss of cristae of mitochondria, and increase in number of lysosomes were noticed.