A human colon adenocarcinoma xenograft--radiation response, cellular composition, and tumor disaggregation

The human colon adenocarcinoma cell line WiDr was xenografted and the tumor characterized. When athymic mice (NCR-nu) were inoculated with 10(6) cells, tumors appeared after 7-14 days with a 93-100% take rate and grew with an initial volume-doubling time of around 6 days. For optimizing the tumor disaggregation method, a comparison was made of two dissociation procedures and of different dissociation times. An enzyme cocktail (collagenase, DNase, pronase) resulted in total viable cell yields of 1-3 X 10(7) cells/g tumor tissue. Cell yield decreased with increasing tumor weight. Disaggregation with trypsin gave lower cell yields; and so, although the plating efficiencies (PEs) were higher, the enzyme cocktail was chosen for tumor disaggregation. On the basis of morphologic identification, cell suspensions prepared from WiDr tumors, by use of the enzyme cocktail for 2 hours, contained 49% malignant cells as well as a significant fraction of nonneoplastic cells. The major nonneoplastic host cell component was macrophage (33%); lymphocytes (13%) and granulocytes (5%) also were present. Host cells could be separated from neoplastic cells by centrifugal elutriation. By mixing various proportions of host and tumor cells, it was subsequently shown that the presence of host cells did not influence the malignant cell PE unless the cell suspensions contained greater than 90% host cells. Single-cell suspensions prepared from WiDr tumors, with use of the enzyme cocktail for 2 hours, were irradiated and then plated for survival (D0 = 1.5 Gy; n = 5) (D0, the 37% dose slope). A comparison was made of the sensitivity to radiation, after the different dissociation methods. The radiation sensitivities after 1.5-hour trypsinization and 2- and 6-hour enzyme cocktail administrations were similar, but after 0.5 hour of trypsin, the cells were more sensitive to radiation.     

Histopathological characterisation of effects of the mouse Pax6 missense mutation on eye development

Mutations in PAX6/Pax6 lead to a variety of ocular anomalies in humans and mice. The aim of the study was to characterise the ocular abnormalities caused by the missense Pax6^Leca4 mutation and compare them to published observations on Pax6 alleles that are functionally equivalent to Pax6⁻ null alleles (such as Pax6^Sey and Pax6^Sey-Neu) and human inherited eye diseases. Ocular features of homozygous Pax6^Leca4/Leca4 and heterozygous Pax6^Leca4/+ embryos at E12.5-E18.5, heterozygous Pax6^Leca4/+ young mice at P18 and heterozygous Pax6^Leca4/+ adults at 12 weeks were analysed histologically with their wild-type Pax6^+/+ littermates. Homozygous Pax6^Leca4/Leca4 fetuses died perinatally with no eyes although an optic cup rudiment with pigmented cells developed. Pax6^Leca4/+ mice were microphthalmic and a range of other severe ocular phenotypes affected both the anterior and the posterior segments. In contrast to Pax6^+/−, the Pax6^Leca4/+ eyes had no goblet cells in the corneal epithelium, the iris was not hypoplastic and there was no lens-corneal epithelial plug. However, microphthalmia was more severe, corneal vascularisation occurred earlier (during fetal stages), pigmented cells were present in the vitreous and corneal stroma and the ciliary body was malformed or abnormal. These results show that, although Pax6^Leca4/+ lacked some eye abnormalities commonly seen in Pax6^Sey/+ and Pax6^Sey-Neu/+ eyes, in most respects their eyes were more severely affected. These differences probably reflect both differences between the Pax6^Leca4 and the Pax6^Sey-Neu mutations and differences in modifier gene expression in different genetic backgrounds. The presence of pigmented cells in the cornea is a novel observation. Some Pax6^Leca4/+ ocular abnormalities were similar to those present in human Peters' anomaly and persistent hyperplastic primary vitreous (PHPV) so Pax6^Leca4/+ mice provide a useful model for some inherited eye diseases.     

The histopathology of freezing injury to the rat spinal cord. A light microscope study. I. Early degenerative changes

In an effort to develop a method of tissue injury which would provide a model for the study of axonal regrowth in adult mammalian central nervous system (CNS), we have analyzed the effects of freezing in the dorsal columns of more than 200 rat spinal cords. The effects of temperature and time of exposure upon the size, shape, distribution and histologic characteristics of the lesion have been assessed during the first seven days following the injury. The upper threshold for injury occurs at -3 degrees C for 15 minutes. Between -3 degrees C and -12 degrees C the tissue changes vary in extent and characteristics. Selective damage to axons and myelin occurs with sparing of the supportive cells followed by proliferation of a cellular matrix. At seven days, the lesions produced by -8 degrees C for 15 to 60 minutes have neither axons nor myelin sheaths and consist of a dense cellular matrix of macrophages and presumed glial cells. With these tissue characteristics, and the preservation of tissue continuity without obstructive barriers, this model would appear to be potentially suitable for the study of axonal regrowth potential in mammalian CNS.     

氟西汀与阿米替林治疗105例抑郁障碍病人的双盲对照试验

目的：评价国产氟西汀的抗抑郁作用及安全性。方法：采用随机、双盲对照、多中心研究，分为国产氟西汀组５７例（男性２２例，女性３５例；年龄４０±ｓ１３ａ），口服氟西汀２０ｍｇ，ｑｄ，阿米替林５７例（男性２７例，女性３０例；年龄４０±１４ａ），口服阿米替林７５ｍｇ，ｂｉｄ，疗程６ｗｋ。结果：氟西汀治疗抑郁障碍的疗效与阿米替林相当，总有效率分别为８５％及９２％（Ｐ＞０．０５）；氟西汀组的主要副作用有口干、便秘、恶心、心动过速等，但较之阿米替林程度轻且发生率低。结论：氟西汀的抗抑郁作用与阿米替林相当，副作用少，服用方便。