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K24 capsular polysaccharide (K24-CPS), with a known structure of a repeating unit, was isolated from the capsule of Klebsiella pneumoniae serotype K24. The polysaccharide was found to suppress the proliferation of Ehrlich ascites tumour (EAT) cells in vitro, but did not alter the cell cycle distribution of cells. K24-CPS treatment reduced the tyrosine phosphorylation of some proteins in EAT cells. Furthermore, the treatment also decreased the expression of c-JUN, but had no effect on the levels of c-FOS and c-MYC. It is speculated that the growth suppression effect of K24-CPS may be related to its effect in down-regulating c-JUN expression.

Esophageal cancer (EC) is the sixthmost common cause of cancer-related deaths worldwide. Surgery is the main treatment option for EC, however, postoperative recurrence rate is high due to cancer metastasis. Even though surgery followed by adjuvant chemotherapy and concurrent radiation have shown favorable efficacies, searching for alternative adjuvant treatments—such as Chinese herbal medicines—for metastatic EC also get patients’ desire. Based on our previous screening among various Chinese herbs, Andrographis paniculata (AP) exhibited anti-tumor effect in human esophageal cancer cells. The present study therefore aimed to evaluate the anti-tumor and anti-metastasis activities of AP and the combined effects of such herbal extract with standard chemotherapeutics for EC, cisplatin and 5-fluorouracil (5-FU). Human squamous esophageal cancer (EC-109) xenograft-bearing mice model was employed to evaluate the in vivo antitumor activities. The absorption of AP water extract was determined in human intestinal Caco-2 cell monolayers. The absorbed AP components have been evaluated for their cytotoxicity using MTT assay. Our preliminary results of in vivo study showed that the number of tumor nodules was decreased in intraperitoneal xenograft-bearing mice treated with AP water extract (1600 mg/kg daily for 20 days). Besides, AP treatment also enhanced the inhibitory effects of cisplatin plus 5-FU on the number of tumor nodules. In view of our in vitro results, the absorbed AP components (APPC) showed significant cytotoxicity on EC-109. Furthermore, seven known chemical constituents were identified in the APPC for the first time, suggesting these absorbed AP components may be responsible for the activities. In conclusion, the AP water extract is effective on inhibiting tumor growth in vivo and the chemical constituents in the absorbed AP components were identified, which may further enhance the understanding of the therapeutic mechanisms of this herb. The anti-metastasis effects of AP will also be further investigated. ACKNOWLEDGEMENT: This work was supported by Food and Health Bureau HKSAR, Health and Medical Research Fund no. 11120981.

Three purified polysaccharide fractions designated as PAC-I, PAC-II, and PAC-III were prepared from Aloe vera L. var. chinensis (Haw.) Berg. by membrane fractionation and gel filtration HPLC. The polysaccharide fractions had molecular weights of 10,000 kDa, 1300 kDa, and 470 kDa, respectively. The major sugar residue in the polysaccharide fractions is mannose, which was found to be 91.5% in PAC-I, 87.9% in PAC-II, and 53.7% in PAC-III. The protein contents in the polysaccharide fractions was undetectable. NMR study of PAC-I and PAC-II demonstrated the polysaccharides shared the same structure. The main skeletons of PAC-I and PAC-II are beta-(1--4)-D linked mannose with acetylation at C-6 of manopyranosyl. The polysaccharide fractions stimulated peritoneal macrophages, splenic T and B cell proliferation, and activated these cells to secrete TNF-alpha, IL-1 beta, INF-gamma, IL-2, and IL-6. The polysaccharides were nontoxic and exhibited potent indirect antitumor response in murine model. PAC-I, which had the highest mannose content and molecular weight, was found to be the most potent biological response modifier of the three fractions. Our results suggested that the potency of aloe polysaccharide fraction increases as mannose content and molecular weight of the polysaccharide fraction increase.

Fluorescence microscopic imaging (FMI) is one of the fastest growing and most powerful techniques to study cellular activities in a living single cell. FMI has been widely used to monitor the temporal and spatial changes of many important intracellular messengers such as Ca2+, H+ and cAMP. In the course of our study of cellular responses with confocal scanning fluorescence microscopy, we detected two sources of artifacts which may render experimental observations invalid. First, the water content of the DMSO used could affect the efficiency of loading of the fluorescence indicator into cells and also give rise to spurious fluorescence spots. Secondly, apparently spontaneous temperature-dependent oscillations of BCECF fluorescence and cellular pulsations were recorded in cells which might be misinterpreted as natural rhythmic behavior. These were later shown to be artifacts arising from changes in refractive indices of the immersion oil due to small fluctuations in temperature, which in turn leads to random shifts of the focal plane erroneously manifest as signal oscillations. Based on these observations, certain recommendations for the control and elimination of false images are presented.

We have written a polynomial regression program in BASIC for an IBM-compatible microcomputer. The program is easy to use as it is entirely menu driven

Incubation of non-excitable murine macrophage cell line PU5-1.8 in K+(140 m M )-Hepes buffer caused membrane depolarization as measured by bis-oxonol and 3,3''-dipropylthio