[Flow cytometer (FCM) in biological characteristics of nasopharyngeal carcinoma xenografts in nude mice]

Tumor tissue from a patient with nasopharyngeal carcinoma was transplanted to nude mice (BALB/c) and had successfully been maintained through ten passages. The nude mice tumor and the primary human tumor were assayed by FCM for the DNA content in addition to conventional pathological examination, chromosome analysis and EBV assay. The tumor incidence in the different passages showed a marked change ranging from 25% to 81% with a mean value of 52% which tended to increase, however. The doubling time of six tumors in the ninth passage showed no great change 6-12 weeks after transplantation with a mean about 4.3 days. But at week 12, there was a significant difference between each tumor volume, ranging from 438 to 1,998 mm3. By FCM, it was found that the DNA index remained constant in both the primary and nude mice tumors. Among the nude mice tumors in different passages, the distribution of various phase cells in cell cycle was similar to that of the primary tumor. In conclusion, the use of FCM to assay the cellular DNA content in nude mice tumor is rapid and sensitive. It is helpful, for the nude mice tumor, in identifying stability of the biological characteristics and in studying of the mechanism of chemotherapy and radiotherapy in the future.

The effects of lead ion on immune function of rabbit alveolar macrophages: quantitation of immune phagocytosis and rosette formation by 51Cr in vitro

Experiments by a 51Cr-labeling technique were performed to investigate the effects of lead (Pb2+) on immune phagocytosis and Fc-rosette formation of rabbit pulmonary alveolar macrophages (PAMs). Evidence is presented that Pb2+ at concentrations of 10(-3) and 10(-4)M could inhibit these functions of PAMs. The degree of inhibition corresponded to the concentration of this heavy metal ion in vitro.

Monotonicity Analysis and the Reduced Gradient Method in Constrained Optimization

The concept of monotonicity analysis is combined with the reduced gradient technique for design optimization. The combination is based on a strategy for applying monotonicity analysis in specified search directions and incorporates this strategy into an iterative procedure for identifying the active inequality constraints in an optimization problem. As the active constraints are identified, the reduced gradient information based on these constraints forms the basis for a variable metric search leading to the constrained optimum. Test results are presented which indicate the performance of two different algorithms using this approach.

Studies on antihepatitic drugs. Total synthesis of (+/-)schizandrin C and its analogs

This paper reports the total synthesis of (+/-) schizandrin, C, namely 5,6,7,8-tetrahydro-1, 12-dimethoxy-2, 3, 10, 11-bismethylenedioxy-6, 7-cis-dimethyldibenzo (a, c) cyclooctene (12B), a new active SGPT lowering principle isolated from the Chinese medical plant Schizandra chinensis, and its 6, 7-trans-dimethyl isomer (16B). We also synthesized two more isomers, namely 5, 6, 7, 8-tetrahydro-3, 10-dimethoxy-1, 2, 11, 12-bismethylenedioxy-6, and 7-cis-(and trans-) dimethyldibenzo (a, c) cyclooctene (12A and 16A). The NMR, UV and mass spectra of these four isomers are discussed. IR (in chloroform), UV, NMR and MS of synthetic schizandrin C (12B) are identical with those of the natural compound.

Two new SiC polytypes belonging to the [(44) n 43]3 structure family

Using a modified Laue method as well as electron diffraction and lattice image methods, two new poly types of SiC, 93R and 261R, have been found which belong to a new structure family [(44) n 43]3 based on 8H (44) stacking.