Inhibition of the skin tumorigenicity of (+/-)-7 beta,8 alpha-dihydroxy-9 alpha,10 alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene by tannic acid, green tea polyphenols and quercetin in Sencar mice

The effect of pretreatment of skin of Sencar mice with topically applied tannic acid, quercetin and green tea polyphenols (GTP) on the skin tumor initiating activity of (+/-)-7 beta,8 alpha-dihydroxy-9 alpha,10 alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE-2) has been evaluated. The animals were pretreated with the plant phenols (tannic acid and quercetin (3000 nmol) or GTP 24 mg/mouse) for 7 days after which they received a single topical application of 200 nmol of BPDE-2 as the initiating agent. Beginning 7 days following initiation animals received twice weekly applications of 3.24 nmol of 12-O-tetradecanoyl phorbol-13-acetate (TPA). Tannic acid and GTP afforded significant protection against skin tumor induction. These inhibitory effects were verified both by prolongation of the latency period and subsequent development of tumors. Quercetin, on the other hand, afforded only moderate protection. Each phenolic compound was found to be highly effective in accelerating the disappearance of BPDE-2 from aqueous medium. Our results suggest that tannic acid and GTP have substantial potential for protecting against the skin tumorigenic response to BPDE-2 and the mechanism of inhibition may involve inactivation of the reactive carcinogenic moiety.

Use of all-trans retinoic acid in the treatment of acute promyelocytic leukemia

Twenty-four patients with acute promyelocytic leukemia (APL) were treated with all-trans retinoic acid (45 to 100 mg/m2/day). Of these, eight cases had been either nonresponsive or resistant to previous chemotherapy; the other 16 cases were previously untreated. All patients attained complete remission without developing bone marrow hypoplasia. Bone marrow suspension cultures were studied in 15 of the 24 patients. Fourteen of these patients had morphological maturation in response to the retinoic acid (1 mumol/L). Chloroacetate esterase and alpha-naphthyl acetate esterase staining as well as electronmicroscopic examination confirmed that retinoic acid-induced cells differentiated to granulocytes with increased functional maturation (as measured by nitroblue tetrazolium reduction, NBT). The single nonresponder to retinoic acid in vitro was resistant to treatment with retinoic acid but attained complete remission after addition of low-dose cytosine arabinoside (ara-C). During the course of therapy, none of the patients showed any abnormalities in the coagulation parameters we measured, suggesting an absence of any subclinical disseminated intravascular coagulation. The only side effects consisted of mild dryness of the lips and skin, with occasional headaches and digestive symptoms. Eight patients have relapsed after 2 to 5 months of complete remission. The others remain in complete remission at 1+ to 11+ months and are still being followed up. We conclude that all-trans retinoic acid is an effective inducer for attaining complete remission in APL.

Studies on the uptake and subsequent tissue distribution of [35S]trithiomolybdate in rats: effects on metallothionein copper in liver, kidney, and intestine

[35S]trithiomolybdate (20 micrograms Mo) was readily absorbed from intestinal sacs in anesthetized rats, and radioactivity was subsequently detectable in all the subcellular fractions examined in the organs sampled. The compound was bound reversibly to proteins in patterns similar to those observed in liver in cattle and sheep. Absorption was depressed by the presence of copper in the sacs. At higher levels of trithiomolybdate (1 mg Mo per rat), the characteristic copper peak of metallothionein disappeared from the liver, kidney, and intestine cytosol fractions in most animals, while the concentration of copper in plasma increased by about 50%. It is suggested that the changes in copper distribution are relevant to the clinical syndromes produced by increased dietary Mo in ruminants.

Exceptional activity of tannic acid among naturally occurring plant phenols in protecting against 7,12-dimethylbenz(a)anthracene-, benzo(a)pyrene-, 3-methylcholanthrene-, and N-methyl-N-nitrosourea-induced skin tumorigenesis in mice

Our recent studies have shown that naturally occurring dietary plant phenols such as tannic acid, quercetin, myricetin, and anthraflavic acid are capable of inhibiting polycyclic aromatic hydrocarbon (PAH) metabolism and subsequent PAH-DNA adduct formation in epidermis of SENCAR mice (M. Das, et al., Cancer Res., 47: 760-766, 1987, and 47: 767-773, 1987). In this study these plant phenols were tested for their effects against PAHs and N-methyl-N-nitrosourea-induced skin tumorigenesis in mice. Each plant phenol was evaluated as a possible anticarcinogen in an initiation and promotion and a complete skin tumorigenesis protocol. In the two-stage tumor protocol in SENCAR mice using 7,12-dimethylbenz(a)anthracene, benzo(a)pyrene, and N-methyl-N-nitrosourea as the initiating agent followed by twice weekly applications of 12-O-tetradecanoylphorbol-13-acetate as tumor promoter each plant phenol afforded significant protection against skin tumorigenicity. The protective effects were verified both by prolongation of latency period and by subsequent tumor development. In the complete carcinogenesis protocol in BALB/c mice using 3-methylcholanthrene as a tumorigen the applications of each of the plant phenols 30 min prior to each PAH application afforded significant protection by delaying the onset and the subsequent development of skin tumors. Our results suggest that these plant phenols have substantial though variable potential for modifying the risk of skin tumorigenicity induced by a wide variety of chemicals and of these tannic acid was shown to have maximal chemoprotective effects.

The use of [185W] thiotungstates for tracer studies in secondary hypocuprosis in cattle

[185W] thiotungstates were synthesized in-vitro and purified by techniques developed for thiomolybdates. [185W] trithiotungstate (15 mg W) injected intravenously into cattle was mainly associated with albumin albumin. The presence of the compound in plasma when injected in larger amounts (0.2 to 1 gW) caused an increase in albumin-bound copper and transiently depressed ceruloplasmin diamine oxidase activity. It is suggested that the long-lived, less costly 185W could prove a convenient alternative to 99Mo for tracer studies with labelled thio-compounds in animals.

Interaction of epicatechins derived from green tea with rat hepatic cytochrome P-450

Green tea has been used for generations in China and Asia as an antipyretic and diuretic. Prior studies have shown that extracts of green tea inhibit the mutagenicity of polycyclic aromatic hydrocarbons and aflatoxin B1. In this study, we investigated the interaction of certain flavonoid components of green tea epicatechin derivatives including (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin-3-gallate (ECG), and (-)-epigallocatechin-3-gallate (EGCG) with rat hepatic microsomal cytochrome P-450 (P-450). The addition of EC, EGC, ECG, and EGCG to hepatic microsomes prepared from phenobarbital (PB)-treated rats resulted in spectral changes characterized by absorbance maxima at 420 nm and minima at 380 nm, typical of modified Type II (reverse Type I) binding. Of the epicatechin derivatives, EGCG and ECG showed greater spectral change with oxidized P-450 and time- and concentration-dependent inhibition of the binding of carbon monoxide to dithionite-reduced cytochrome P-450. The addition of EC, EGC, ECG, and EGCG to microsomes prepared from control, PB- or 3-methylcholanthrene-treated rats resulted in a dose-dependent inhibition of cytochrome P-450-dependent aryl hydrocarbon hydroxylase, 7-ethoxycoumarin O-deethylase, and 7-ethoxyresorufin O-deethylase activities. EGCG was the most potent in this regard. Green tea polyphenols and epicatechin derivatives also significantly inhibited NADPH-cytochrome c reductase activity. An examination of the structure activity relationship of epicatechin derivatives suggests that the inhibitory effect on the microsomal enzyme system may be due to the galloyl groups or hydroxyl groups on the molecule. Our data indicate that these extracts of green tea may have potential as anticarcinogens.

A Chinese version of the Mini-Mental State Examination; impact of illiteracy in a Shanghai dementia survey

A dementia screening survey was carried out in Shanghai using a culturally adapted Chinese version of the Mini-Mental State Examination. A probability sample of 5055 community-dwelling elderly in Shanghai was surveyed, 1497 aged 55-64, 2187 aged 65-74, and 1371 aged 75 and over. In the 73.3% of the subjects who had gone to school, using the age and education adjustments suggested by Kittner et al. (1986), [Kittner et al. J Chron Dis 39: 163-170; 1986] suitable cutoff scores could readily be selected to identify the subjects who should be examined intensively for the presence of dementia. However, in the 26.7% who had not gone to school, there was a significant increase in low scores on the mental status test as well as a different error pattern, reflecting the lack of formal education. Methods for following cognitive changes in illiterate individuals need further development.

The uptake and intracellular distribution of [35S]trithiomolybdate in bovine liver in vivo

[35S] trithiomolybdate was administered intravenously to a group of four steer at two dose rates, 1 and 26 mg Mo per animal. Radioactivity appeared rapidly in the liver and was distributed in all the subcellular fractions examined. Examination by Sephadex G-100 gel-filtration of the cytosol fraction showed that distinct 35S-binding protein peaks were present. The protein-bound radioactivity was displaceable and was identified as [35S]thiomolybdates. No radioactivity eluted with metallothionein, but 35S was associated with the high molecular weight copper fraction, eluted in the void volume of the column, which increased transiently after the administration of the higher dose. It was suggested that the presence of protein-bound thiomolybdates in the liver gave rise to new ligands, which altered the equilibrium of copper between the different metal-binding proteins. This might be similar to the alteration in the copper-binding of albumin produced by the presence of thiomolybdates.

[Evaluation of CT scan for carcinoma of the gastric cardia]

CT scans of 50 cases with carcinoma of gastric cardia were analyzed. 45 cases were operated but 12 were explored only. The causes of unresectability were: bulky primary tumor, regional lymph node involvement, infiltration of the adjacent structures, e.g. liver, pancreas, spleen and diaphragm, intragastric extension and ascites. By CT scan, the detection rate of the visceral organ involvement was: diaphragm 4/7, pancreas 3/10, liver 4/6 and spleen 5/6. Therefore, it is very important to have a preoperative CT scan for carcinoma of gastric cardia.

[Combination of radiation, chemotherapy and surgery in rectal cancer--an analysis of 128 patients]

The results of 128 patients with rectal cancer treated by the combination of surgery, preoperative radiotherapy and chemotherapy from June 1975 to December 1979 are reported and compared with those by operation alone. The 5 year survival rates of the different groups were: 69.5% (16/23) for radical surgery plus preoperative radiotherapy and chemotherapy (RRCG), 56% (14/25) for radical surgery plus preoperative radiotherapy, 53.8% (7/13) for radical surgery plus chemotherapy and 40% (10/25) for radical surgery alone. The 5 year survival rate of RRCG was significantly higher than that of the radical surgery alone group (P less than 0.05). The authors believe that the combination of preoperative radiotherapy, chemotherapy plus radical surgery improves the 5 year survival rate and is worthy of further study.

[Preoperative chemotherapy of esophageal cancer]

A series of 25 patients with advanced esophageal cancer treated from Mar. 1981 to Sep. 1982 by preoperative chemotherapy plus surgery is reported. All the patients came from the hospitals of the cooperative research group and were randomized into chemotherapy and control groups. They were proved by X-ray, cytology and histopathology prior to treatment. By histology, 22 cases were squamous cell carcinoma, 1 adenocarcinoma and 2 squamous adenocarcinoma. The COF chemotherapy consisted of Vincristine 1 mg, cyclophosphamide 600 mg and 5-fluorouracil 500 mg IV on days 1 and 8 with or without the addition of Pingyangmycin, a drug equivalent to Bleomycin A5, at the dose of 10 mg IM on days 1, 3, 6 and 8. The interval between the ending of chemotherapy and the surgical resection was 5-6 days. The results showed that preoperative chemotherapy caused no myelosuppression, but merely mild gastrointestinal symptoms. All patients were operated and resected without difficulty. The subjective improvement in various degrees and the shrinkage of tumor in the X-ray films were present in 5/25 cases who received preoperative chemotherapy. The histopathological changes in the chemotherapy and control groups (16 specimens) were different. In the chemotherapy group, excessive keratinization in the squamous component of the esophageal cancerous tissue appeared in the resected specimens. The incidence of degeneration and necrosis in the squamous epithelium adjacent to carcinoma was higher in the chemotherapy group (P less than 0.01). The results suggested that such combined modality is worth further study.

Development of a radioimmunoassay for prostaglandin D2 using an antiserum against 11-methoxime prostaglandin D2

A sensitive and specific radioimmunoassay for prostaglandin D2 has been developed using its stabilized 11-methoxime derivative, which was obtained after treatment of prostaglandin D2 with methoxamine-HCl. The antiserum was obtained after injection of prostaglandin D2-methoxamine coupled to bovine serum albumin. A (125I)-Histamide prostaglandin D2-methoxamine tracer was prepared by iodination of the corresponding histamide, followed by thin layer chromatography purification. The sensitivity of the assay was 280 femtomoles per ml at 50% displacement. The cross reactivities were 15% with prostaglandin D1-methoxamine and less than 0.20% with other prostaglandins. Determination of the half-life of prostaglandin D2 in a solution containing albumin was also carried out, since it has been shown to catalyze prostaglandin D2 destruction. The unstability of this prostaglandin is due to the presence of a beta-hydroxy ketone group, and all prostaglandins possessing this labile moiety could be stabilized by such a derivatization before developing a radioimmunoassay.