Origin, transfer and distribution of cantharidin-related compounds in the blister beetle Hycleus scabiosae

Cantharidin provides chemical protection for the coleopteran families Meloidae and Oedemeridae. In the present study, it was observed that cantharidin concentration in Hycleus scabiosae was slightly decreased from mated females (mean = 0.011 mg/mg of dry weight) to males (mean = 0.010 mg/mg) and considerably diminished in relation to virgin females (mean = 0.005 mg/mg). Significant concentrations of palasonin (21.69 ng/mg among virgins and 17.49 ng/mg in mated females) and palasoninimide (14.62 ng/mg in virgins and 9.17 ng/mg in mated females) were found in H. scabiosae. Palasonin, palasoninimide and cantharidinimide content of eggs were measured as 5.61, 7.69 and 7.80 ng/mg respectively. Surprisingly, males showed no trace of cantharidin-related compounds (CRCs); therefore CRCs in H. scabiosae could not be transferred from males to females and based on experiments employing its deuterated form, cantharidin is probably independently synthesized in females from the male nuptial transfer. An inseminated female incorporates about 38.5 ng of cantharidin (0.34 percent of the maternal content), 196.35 ng of palasonin (91.82 percent of maternal content) and 269.15 ng of palasoninimide (96.70 percent maternal content) into each egg mass during oviposition. It seems that eggs of this meloid species exploit a different array of protective chemicals by increasing the ratio of CRCs versus cantharidin. CRCs are less toxic than cantharidin; therefore, such compounds might have been deposited in eggs as a safer substitute for cantharidin to provide effective protection, but does not simultaneously harm the susceptible embryo.(AU)

Risk of colorectal cancer in relatives: A case control study.

Background: In around 10 to 15% of all colorectal cancer (CRC) cases, a positive family history of colorectal cancer is observed . Although increased risk of colorectal cancer in individuals with a family history of the disease has been observed consistently in the past studies, limited information is available on colorectal cancer associated with family history in Iran. Aims : The purpose of this study is to define the risk of colorectal cancer associated with a family history of cancer. Setting and Design: The present study was designed as an unmatched case control study. The cases were 393 patients with histologically confirmed colorectal carcinomas and there were 393 controls, randomly selected from among the healthy participants in a health survey. Methods : The family history was extracted from a standard history form completed by the patient or from the record created by a health care provider. Statistical Analysis: Mantel-Heanszel Odds Ratio was computed for removing the confounding effect of age and sex. Results : A positive family history of cancer was reported by 36.4 and 24.4% among the cases and controls, respectively. Colorectal cancer risk increased two-fold in subjects who reported having first degree relatives with cancer. The adjusted odds ratio was 4.76, indicating that having a positive family history of colorectal cancer among relatives increased one's risk of colorectal cancer about 4.5-fold. Conclusion: According to our findings, a family history of cancer increased the risk of CRC. Due to this fact that there is no current colorectal cancer screening program in Iran, it is recommended that first degree relatives of patients with colorectal cancer should be considered as a priority group for screening programs.