[Effect of HH07A, A derivative of hainanensine, on DNA polymerase I]

The effect of HH07A on DNA polymerase I in a cell free system was studied. The results showed that HH07A strongly inhibited the DNA synthesis catalyzed by DNA polymerase I in a dose dependent manner. Further results indicated that the DNA synthesis decreased significantly after DNA polymerase I was preincubated with HH07A. However, no change was found when DNA template was preincubated with HH07A. These results suggest that the inhibitory action of HH07A appeared to be on the enzyme molecules rather than on the DNA template.

[Studies on the anticancer effect of HH07A, a derivative of hainanensine]

The effect of HH07A on the growth of tumor cells in vitro was investigated using the techniques of cell growth curve determination and soft-agar colony-forming assay. The result showed that HH07A inhibited the growth of L1210 cells and HL-60 cells at a concentration of 1.5 micrograms.ml-1 and 4.0 micrograms.ml-1, respectively. Among the cells tested, L1210 cells were shown to be the most sensitive, followed by KB cells and HL-60 cells (with IC50 of 2.29, 4.13 and 4.36 micrograms.ml-1, respectively). Normal mouse granulocyte-macrophage progenitor cells (GM-CFC) were less sensitive to the drug (with IC50 of 11.15 micrograms.ml-1) as compared with the tumor cells. As they were exposed to HH07A 3.5 micrograms.ml-1 for 5 days, HL-60 cells did not show NBT reductive ability. Intraperitoneal injection of HH07A exerted inhibitory effect on the ascitic tumors of L1210 and S180 in mice. Oral or ip administration of HH07A also showed some effect on S180 solid tumors in mice.

Efficacy of ivermectin for control of microfilaremia recurring after treatment with diethylcarbamazine. II. Immunologic changes following treatment

We compared the effect of a single dose of ivermectin with that of a standard course of diethylcarbamazine (DEC) on several parameters of the host's antifilarial immune response in 60 patients with bancroftian filariasis enrolled in a double-blind drug trial. All participants had measurable serum levels of antifilarial antibodies and parasite antigens at the onset of the study. Drug-induced clearance of microfilaremia was associated with a temporary increase in HC 11 antigenemia and a decrease in serum levels of antibodies to soluble filarial antigens. Antigenemia progressively declined in patients who remained amicrofilaremic after treatment, but declined and then increased in persons with recurrent microfilaremia. Treatment triggered a sustained increase in serum levels of interleukin-1, tumor necrosis factor, and interleukin-6 in all patients studied. Although ivermectin and DEC are believed to exert their antiparasite activity via different mechanisms, the same pattern of serologic changes was observed in patients treated with either drug.

Efficacy of ivermectin for control of microfilaremia recurring after treatment with diethylcarbamazine. I. Clinical and parasitologic observations

We compared the efficacy of a single dose of ivermectin with that of a standard course of diethylcarbamazine (DEC) for the control of microfilaremia in 60 patients with bancroftian filariasis who had developed recurrent microfilaremia after each of three or more prior treatments with DEC. The study was done as a randomized, double-blind trial. Complete, but in some cases, transient clearance of microfilaremia was observed in both treatment groups. At one year, recurrent microfilaremia was present in seven patients treated with ivermectin and in five treated with DEC. Pretreatment levels of microfilaremia were significantly higher in patients who relapsed within one year after treatment than in those who remained amicrofilaremic. Side effects with both treatments were common, but mild. Febrile reactions were more frequent in the ivermectin group; localized reactions consistent with a flare-up of acute filarial disease occurred mostly in the DEC group. We conclude that ivermectin is an effective and practical alternative to DEC for treatment of recurrent microfilaremia due to bancroftian filariasis.

Characteristic autofluorescence for cancer diagnosis and its origin

The autofluorescence spectra of human tissues excited with the 365-nm line of pulsed xenon ion laser have been measured. The autofluorescence spectra of cancer tissues usually show characteristic peaks near 630 nm and 690 nm, which do not appear in the spectra of the corresponding normal tissues. This characteristic fluorescence can be taken as a criterion for cancer diagnosis; a consistency of 89% with the traditional biopsy method has been obtained in preliminary clinical application to the diagnosis of buccal carcinoma. Spectroscopic investigations suggest that the porphyrin compounds localized and retained in cancer tissues might be responsible for this characteristic autofluorescence.