茶儿茶素对癌细胞凋亡作用的研究

本文研究茶儿茶素诱导白血病癌细胞凋亡的作用及其机理。结果表明 ,茶儿茶素 (包括EGCG ,ECG和EGC)在浓度超过 5 0 μg ml时促进白血病癌细胞的凋亡 ,并在 5 0～ 30 0 μg ml浓度范围内存在正的量 -效关系。茶儿茶素诱导癌细胞凋亡的可能机理之一是促进自由基的产生 ,并抑制癌细胞的抗氧化酶     

Cancer incidence in pet dogs: findings of the Animal Tumor Registry of Genoa, Italy

BACKGROUND: The occurrence of spontaneous tumors in pet animals has been estimated in a few European and North American veterinary cancer registries with dissimilar methodologies and variable reference populations. OBJECTIVES: The Animal Tumor Registry (ATR) of Genoa, Italy, was established in 1985 with the aim of estimating the occurrence of spontaneous tumors in dogs. METHODS: Six thousand seven hundred and forty-three tumor biopsy specimens were received from local veterinarians in the Municipality of Genoa between 1985 and 2002. Three thousand and three hundred and three (48.9%) biopsy specimen samples were diagnosed as cancer and were coded according to the International Statistical Classification of Diseases (ICD-9). RESULTS: Mammary cancer was the most frequently diagnosed cancer in female dogs, accounting for 70% of all cancer cases. Incidence of all cancers was 99.3 per 100,000 dog-years (95% CI: 93.6-105.1) in male dogs and 272.1 (95% CI: 260.7-283.6) in female dogs. The highest incidence rates were detected for mammary cancer (IR = 191.8, 95% CI: 182.2-201.4) and for non-Hodgkin's lymphoma (IR = 22.9, 95% CI: 19.7-26.5) in bitches and for non-Hodgkin's lymphoma (IR = 19.9, 95% CI: 17.4-22.7) and skin cancer (IR = 19.1, 95% CI: 16.6-21.8) in male dogs. All cancer IR increased with age ranging between 23.7 (95% CI: 18.4-30.1) and 763.2 (95% CI: 700.4-830.1) in bitches and between 16.5 (95% CI: 12.8-21.1) and 237.6 (95% CI: 209.1-269.0) in male dogs aged < or =3 years and >9-11 years. CONCLUSION: This study summarizes the work done by the ATR of Genoa, Italy, between 1985 and 2002. All cancer incidence was 3 times higher in female than in male dogs, a difference explained by the high rate of mammary cancer observed in bitches. Because a biopsy specimen was required to make a cancer diagnosis, cancer rates for internal organs cancers, such as respiratory and digestive tract cancers may have been underestimated in the study population.     

Anti-erythrocyte antibodies and disease associations in anemic and nonanemic dogs

BACKGROUND: Flow cytometry has been used to detect anti-red blood cell (RBC) antibodies in dogs with immune-mediated hemolytic anemia (IMHA), but the prevalence of anti-RBC antibodies in anemic and nonanemic dogs with a variety of different diseases has not been assessed previously. HYPOTHESIS: We hypothesized that anti-RBC antibodies would be more common in anemic dogs and in dogs with immune-mediated disorders and cancer. ANIMALS: Blood samples from 292 dogs were analyzed prospectively by flow cytometry for anti-RBC antibodies. METHODS: Blood samples from 147 anemic and 145 nonanemic dogs were evaluated by flow cytometry to detect surface-bound immunoglobulin (Ig) G and IgM antibodies on RBC. Disease associations with RBC antibodies were determined, as was the correlation between disease status and the percentage of Ig(+) RBC. The specificity and sensitivity of flow cytometry and clinical variables for the diagnosis of IMHA were compared by Bayesian analysis. RESULTS: Anemic dogs were significantly more likely to be positive for anti-RBC antibodies (IgG, IgM, or both) than nonanemic dogs. Anemic dogs also had significantly higher percentages of Ig(+) RBC than nonanemic dogs, whereas dogs with IMHA had significantly higher percentages of Ig(+) RBC than dogs with all other diseases. Dogs with IMHA, infectious diseases, and immune-mediated thrombocytopenia were significantly more likely to have anti-RBC antibodies than dogs with other medical or surgical diseases. CONCLUSIONS: Anemic dogs with immune-mediated diseases and infectious diseases were at the highest risk for the development of anti-RBC antibodies, and flow cytometry for the detection of IgG on RBC was highly sensitive and specific for the diagnosis of IMHA.     

Metronomic therapy with cyclophosphamide and piroxicam effectively delays tumor recurrence in dogs with incompletely resected soft tissue sarcomas

Background: Continuous administration of low doses of cyclophosphamide and standard doses of cyclooxygenase‐inhibiting drugs has been shown to suppress tumor angiogenesis, reverse immunosuppression, and deplete regulatory T cells in cancer models. Hypothesis: We hypothesized that continuous treatment with low‐dose cyclophosphamide and full‐dose piroxicam would delay tumor recurrence in dogs with soft tissue sarcomas (STS). Animals: Eighty‐five dogs with incompletely resected STS, 30 treated dogs, and 55 contemporary control dogs. Methods: Treatment outcomes in 85 dogs with incompletely resected STS were evaluated in a retrospective study. Dogs in the treatment group received continuously administered low‐dose cyclophosphamide (10 mg/m²) and standard dose piroxicam (0.3 mg/kg) therapy. Time to local tumor recurrence (disease‐free interval; DFI) was compared between the 30 treated dogs and 55 untreated control dogs matched for age and tumor site and grade. Results: DFI was significantly (P < .0001) prolonged for STS of all sites (trunk and extremity) in treated dogs compared with untreated control dogs. The DFI also was significantly longer in treated dogs when tumor site (trunk and extremity) was compared. Twelve treated dogs (40%) experienced mild toxicity (grade 1 and 2) at some point during treatment and 1 dog developed grade 4 cystitis. Every other day dosing was tolerated better than daily dosing. Conclusions: Metronomic therapy with cyclophosphamide and piroxicam was very effective in preventing tumor recurrence in dogs with incompletely resected STS. These findings suggest that further evaluation of this approach is warranted as adjuvant therapy in dogs with highly metastatic tumors such as osteosarcoma and melanoma.     

茶抗癌活性的动物试验和人体研究新进展

茶和茶叶组份抗癌活性的科学证据在体外细胞体系研究中业已确定,其分子作用机理正在被进一步阐明。这方面详细的文献综述近来已有报导。本文就最近几年动物试验,人体流行病学,人体干预研究以及临床实验方面的研究进展作一综述。     

Anti-tumor promoters phenolics and triterpenoid from Hippophae rhamnoides

A 70% ethanol extract of the branches of Hippophae rhamnoides exhibited remarkable antitumor activity in an in vivo two-stage carcinogenesis test in mice using 7,12-dimethylbenz[a]anthracene as an initiator and 12-O-tetradecanoylphorbol-13-acetate (TPA) as a promoter. From the active fraction of the 70% ethanol extract, three phenolic compounds, (+)-catechin (1), (+)-gallocatechin (2), and (−)-epigallocatechin (3) and a tritepenoid, ursolic acid (4) were isolated and identified. These compounds were evaluated for their inhibitory effects on TPA-induced inflammation (1 µg/ear) in mice. Within the tested compounds, 3 and 4 showed marked anti-inflammatory effects, with a 50% inhibitory dose of 1.7 and 0.2 μmol/ear.     

Selective modulation of P-glycoprotein activity by steroidal saponines from Paris polyphylla

Bio-guided fractionation of the roots of Paris polyphylla (Trilliaceae), based on inhibition of P-glycoprotein-mediated daunorubicin efflux in K562/R7 cell line, led to isolation and identification of the three saponins 3-O-Rha(1-->2)[Ara(1-->4)]Glc-pennogenine, gracillin and polyphyllin D, and the two ecdysteroids 20-hydroxyecdysone and pinnatasterone. These compounds were tested for multidrug reversion on P-glycoprotein (ABCB1) with both drug-selected and transfected cell lines, and also on Breast Cancer Resistance Protein (BCRP/ABCG2). By contrast to a weak efficiency on BCRP, the three saponins displayed significant effects as inhibitors of P-glycoprotein-mediated drug efflux.     

功能性食品在抗癌症方面的应用

所谓功能性食品就是指在满足基本的营养需要的同时还能够发挥额外的生理作用,如预防或延迟慢性疾病的发作等。过去数十年的研究已经发现了大量的可以防止细胞氧化的营养物质。这些水果和蔬菜中的成分能够作为抗氧化剂清除体内的有害的能引起疾病的自由基。功能性食品在抗癌症方面有着广阔的应用前景。     

Seasonal movements of Atlantic rock crab (Cancer irroratus Say) transplanted into a mussel aquaculture site

Approximately 73 000 Atlantic rock crab (Cancer irroratus) were captured in coastal waters and transferred to an estuarine mussel aquaculture site in Prince Edward Island, Canada, in an effort to control overgrowth by the invasive tunicate Ciona intestinalis. To assess whether transplanted crabs remained in the vicinity of mussel farms, acoustic tags were attached to 25 resident and 25 transplanted individuals (all males) and their movements were monitored for 1 year, from September 2006 to August 2007. Resident crabs tended to occupy (within 1.6 km) the middle estuary where the majority of mussel farms are located. They left this area during winter, possibly to reach upstream overwintering grounds, and most returned to the middle estuary in spring. In contrast, translocated crabs exhibited a marked downstream movement (<5.5 km distant) in autumn and winter and few returned into the middle estuary in spring. Results suggest that transplanting large numbers of additional rock crabs is not an effective means to reduce the effects of invasive tunicates on mussel farms.