Differentiation and oncogenesis: phenotypically distinct lens tumors in transgenic mice

We report on two lines of transgenic mice that express a murine alpha A-crystallin/SV40 tumor antigen fusion gene in the eye lens. The alpha T1 line develops fast growing, poorly differentiated lens tumors, whereas the alpha T2 line produces lens tumors that are slow growing and well differentiated. There is a striking difference between these two lines in the temporal and spatial patterns of tumor antigen expression during initial lens development. In the alpha T1 line, the transgene is expressed very early in development in most lens cells, and no primary fiber differentiation takes place. In the alpha T2 line, transgene expression occurs after primary fiber formation has been initiated, and is restricted to differentiating fiber cells. The anterior epithelium from both alpha T lines undergoes normal development and remains morphologically normal until after birth, although in alpha T1 mice, these anterior cells produce considerable amounts of SV40 tumor antigens. This suggests that the state of differentiation of the lens cell plays an important role in its response to oncogene products.

Cell-specific induction of mouse Cyp1a1 mRNA during development

The dioxin-inducible cytochrome P(1)450 (Cyp1a1 gene) and P(3)450 (Cyp1a2 gene) enzymes have been implicated in the metabolism of numerous polycyclic hydrocarbons and arylamines, respectively. The prototypic inducer 3-methylcholanthrene was given to the pregnant mouse, and the intrauterine response was examined with the use of in situ hybridization. During the early postimplantation stage, inducible Cyp1a1 mRNA is detected in specific cell types in the extraembryonic tissues only. This selective expression along with the lack of detectable constitutive Cyp1a1 and constitutive or inducible Cyp1a2 gene transcripts between 5.3 and 14.5 days of gestation suggest that (i) these two genes appear to play no endogenous role during differentiation and (ii) the metabolic activity of the inducible Cyp1a1 enzyme may be important to the embryo and fetus from the standpoint of protection against toxic foodstuff and other environmental chemicals.

Effect of high tibial osteotomy on upper tibial venous drainage: study by intraosseous phlebography in primary osteoarthritis of knee joint

The effect of high tibial osteotomy on the upper tibial venous pattern in primary painful osteoarthritis of the knee joint was studied by preoperative and three to six months postoperative intraosseous phlebograms. The normal phlebographic pattern was established by phlebograms in five patients with normal knees. The preoperative engorgement, tortuosity of the medullary sinusoids, and slow dye clearance showed a remarkable conversion to a near normal appearance after the operation. Rest pain disappeared in all patients after the osteotomy, suggesting that venous congestion is the cause of 'rest pain'.

Affinity binding of non-histone chromatin proteins to the X chromosome of Drosophila by in situ chromatin reconstitution and its significance

Cytophotometric analysis of the in situ binding affinity of non-histone chromosomal protein (NHCP) to the polytenic X chromosome and autosome of Drosophila melanogaster has been carried out using Feulgen-Napthol Yellow S staining technique. The results reveal that the mean transformed absorbance ratio (male:female) with a 547 nm interference band filter for the two specific segments of the X chromosome is close to 0.5, while for a specific segment of an autosome it is close to 1.0, in the two sets of control; namely, the positive control (no treatment) and the negative control (treated with 1 M-urea+2M-NaCl) as well as in the reconstituted chromosomal preparations, which received 1 M-urea+2M-NaCl and the NHCP isolated from D. melanogaster. In contrast, the transformed absorbance ratios (male:female) with a 433 nm interference band filter yielded an interestingly different result. The ratios with a 433 nm filter for the X chromosome segments are significantly greater than 0.5 in all three sets of experiments. This finding by itself suggests that the NHCP binding affinity is dissimilar for the X chromosomes of male and female. When the 433 to 547 nm absorbance ratios were compared among the three sets, the data clearly revealed that in both positive control and NHCP reconstituted samples, the absorbance ratios (i.e. 433:547 nm) are significantly different between X chromosomes from males and those from females, while they are different between autosomes from males and females. The ratios are also not significantly different between male and female, either for the X chromosome or for the autosome in the negative control. These findings, therefore, suggest that there is a stronger binding affinity of NHCP for the male X chromosome of Drosophila, and reinstate the view that the X-chromosomal hyperactivity in male Drosophila is the consequence of a regulated organizational change in the DNA template.

Evaluation of 496 menstrual regulation and abortion patients in Calcutta

From March to December 1975, 496 patients were studied to compare the safety and effectiveness of menstrual regulation (MR) performed with a Karman hand syringe and first trimester abortion performed with an electric vacuum aspirator. All procedures were done on an outpatient basis. The complication rate for the MR patients was significantly lower than that for the other first trimester abortion patients. Study results indicate that MR with the Karman syringe is a safer, simpler and less costly procedure than first trimester abortion with the electric vacuum aspirator. Further research and study are necessary to determine the effect of the initial and repeat MR procedures on women's menstrual patterns and future pregnancies, including any subsequent prematurity, stillbirths and Rh immunization.