Co-carcinogenic effects of several Korean foods on gastric cancer induced by N-methyl-N'-nitro-N-nitrosoguanidine in rats

Capsaicinoids and Their Effects on Cancer: The "Double-Edged Sword" Postulate from the Molecular Scale

Capsaicinoids are a unique chemical species resulting from a particular biosynthesis pathway of hot chilies (Capsicum spp.) that gives rise to 22 analogous compounds, all of which are TRPV1 agonists and, therefore, responsible for the pungency of Capsicum fruits. In addition to their human consumption, numerous ethnopharmacological uses of chili have emerged throughout history. Today, more than 25 years of basic research accredit a multifaceted bioactivity mainly to capsaicin, highlighting its antitumor properties mediated by cytotoxicity and immunological adjuvancy against at least 74 varieties of cancer, while non-cancer cells tend to have greater tolerance. However, despite the progress regarding the understanding of its mechanisms of action, the benefit and safety of capsaicinoids' pharmacological use remain subjects of discussion, since CAP also promotes epithelial-mesenchymal transition, in an ambivalence that has been referred to as "the double-edge sword". Here, we update the comparative discussion of relevant reports about capsaicinoids' bioactivity in a plethora of experimental models of cancer in terms of selectivity, efficacy, and safety. Through an integration of the underlying mechanisms, as well as inherent aspects of cancer biology, we propose mechanistic models regarding the dichotomy of their effects. Finally, we discuss a selection of in vivo evidence concerning capsaicinoids' immunomodulatory properties against cancer.

Capsicum annuum L. and its bioactive constituents: A critical review of a traditional culinary spice in terms of its modern pharmacological potentials with toxicological issues

Capsicum annuum L., commonly known as chili pepper, is used as an important spice globally and as a crude drug in many traditional medicine systems. The fruits of C. annuum have been used as a tonic, antiseptic, and stimulating agent, to treat dyspepsia, appetites, and flatulence, and to improve digestion and circulation. The article aims to critically review the phytochemical and pharmacological properties of C. annuum and its major compounds. Capsaicin, dihydrocapsaicin, and some carotenoids are reported as the major active compounds with several pharmacological potentials especially as anticancer and cardioprotectant. The anticancer effect of capsaicinoids is mainly mediated through mechanisms involving the interaction of Ca²⁺ -dependent activation of the MAPK pathway, suppression of NOX-dependent reactive oxygen species generation, and p53-mediated activation of mitochondrial apoptosis in cancer cells. Similarly, the cardioprotective effects of capsaicinoids are mediated through their interaction with cellular transient receptor potential vanilloid 1 channel, and restoration of calcitonin gene-related peptide via Ca²⁺ -dependent release of neuropeptides and suppression of bradykinin. In conclusion, this comprehensive review presents detailed information about the traditional uses, phytochemistry, and pharmacology of major bioactive principles of C. annuum with special emphasis on anticancer, cardioprotective effects, and plausible toxic adversities along with food safety.

Protective Role of Capsaicin in Neurological Disorders: An Overview

Different pathological conditions that begin with slow and progressive deformations, cause irreversible affliction by producing loss of neurons and synapses. Commonly it is referred to as 'protein misfolding' diseases or proteinopathies and comprises the latest definition of neurological disorders (ND). Protein misfolding dynamics, proteasomal dysfunction, aggregation, defective degradation, oxidative stress, free radical formation, mitochondrial dysfunctions, impaired bioenergetics, DNA damage, neuronal Golgi apparatus fragmentation, axonal transport disruption, Neurotrophins (NTFs) dysfunction, neuroinflammatory or neuroimmune processes, and neurohumoral changes are the several mechanisms that embark the pathogenesis of ND. Capsaicin (8-Methyl-N-vanillyl-6-nonenamide) one of the major phenolic components in chili peppers (Capsicum) distinctively triggers the unmyelinated C-fiber and acts on Transient Receptor Potential Vanilloid-1, which is a Ca²⁺ permeable, non-selective cation channel. Several studies have shown the neuroprotective role of capsaicin against oxidative damage, behavioral impairment, with 6-hydroxydopamine (6-OHDA) induced Parkinson's disease, pentylenetetrazol-induced seizures, global cerebral ischemia, and streptozotocin-induced Alzheimer's disease. Based on these lines of evidence, capsaicin can be considered as a potential constituent to develop suitable neuro-pharmacotherapeutics for the management and treatment of ND. Furthermore, exploring newer horizons and carrying out proper clinical trials would help to bring out the promising effects of capsaicin to be recommended as a neuroprotectant.

RNA-Seq Analysis Reveals Dendrobium officinale Polysaccharides Inhibit Precancerous Lesions of Gastric Cancer through PER3 and AQP4

Purpose

There has been mounting evidence that Dendrobium officinale polysaccharides (DOP), a traditional Chinese medicine, are a potential candidate treatment for N-methyl-N'-nitro-N-nitrosoguanidine- (MNNG-) induced precancerous lesions of gastric cancer (PLGC). However, the underlying mechanisms have not been adequately addressed.

Method

We utilized RNA-Seq analysis to investigate possible molecular targets and then used Venn software to identify the differentially expressed genes (DEGs). Further, we analyzed these DEGs with core analysis, upstream analysis, and interaction network analysis by IPA software and validated the DEGs by real-time PCR and Western blot.

Result

78 DEGs were identified from the normal control group (CON), the PLGC model group (MOD), and the DOP-treated group (DOP) by the Venn software. Further analysis of these DEGs, including core analysis, upstream analysis, and interaction network analysis, was performed by Ingenuity Pathway Analysis (IPA). The main canonical pathways involved were SPINK1 Pancreatic Cancer Pathway (-log (P value) = 4.45, ratio = 0.0667) and Circadian Rhythm Signaling (-log (P value) = 2.33, ratio = 0.0606). Circadian Rhythm Signaling was strongly upregulated in the model group versus the DOP group. CLOCK was predicted to be strongly activated (z-score = 2.236) in upstream analysis and induced the downstream PER3. In addition, the relative mRNA expression levels of seven DEGs (CD2AP, ECM1, AQP4, PER3, CMTM4, ESRRG, and KCNJ15) from RT-PCR agreed with RNA-Seq data from MOD versus CON and MOD versus DOP groups. The gene and protein expression levels of PER3 and AQP4 were significantly downregulated in the PLGC model and significantly increased by DOP treatment (9.6 g/kg).

Conclusions

These findings not only showed DOP inhibits PLGC development by upregulating the PER3 and AQP4 gene and protein expression but also suggested that its mechanism of action involved modulating the Circadian Rhythm Signaling pathway.

The Effects of Capsaicin on Gastrointestinal Cancers

Gastrointestinal (GI) cancers are a group of diseases with very high positions in the ranking of cancer incidence and mortality. While they show common features regarding the molecular mechanisms involved in cancer development, organ-specific pathophysiological processes may trigger distinct signaling pathways and intricate interactions with inflammatory cells from the tumoral milieu and mediators involved in tumorigenesis. The treatment of GI cancers is a topic of increasing interest due to the severity of these diseases, their impact on the patients' survivability and quality of life, and the burden they set on the healthcare system. As the efficiency of existing drugs is hindered by chemoresistance and adverse reactions when administered in high doses, new therapies are sought, and emerging drugs, formulations, and substance synergies are the focus of a growing number of studies. A class of chemicals with great potential through anti-inflammatory, anti-oxidant, and anti-tumoral effects is phytochemicals, and capsaicin in particular is the subject of intensive research looking to validate its position in complementing cancer treatment. Our paper thoroughly reviews the available scientific evidence concerning the effects of capsaicin on major GI cancers and its interactions with the molecular pathways involved in the course of these diseases.

Kimchi and Other Widely Consumed Traditional Fermented Foods of Korea: A Review

Different types of fermented foods such as chongkukjang, doenjang, ganjang, gochujang, and kimchi are plentifully available and widely consumed in north eastern Asian countries including Korea. Among them, kimchi is one of the most popular Korean traditional food. It is prepared by fermenting the baechu cabbage together with other vegetables and lactic acid bacteria (LAB) with functional potential. Many types of ingredients are added to kimchi to enhance its taste, flavor, nutritional value, texture etc. A number of bacteria are involved in the fermentation of kimchi, but LAB are the dominant species in the fermentation process. The addition of other sub ingredients and formation of different by-products during fermentation eventually leads to eradication of putrefactive and pathogenic bacteria, and also increase the functionalities, nutritional and nutraceutical potential of kimchi. Kimchi possesses anti-inflammatory, antibacterial, antioxidant, anticancer, antiobesity, probiotic properties, cholesterol reduction, and antiaging properties. In the present review an attempt has been made to review the different types of fermented foods found in the Korean peninsula with detailed scientific research regarding preparation, processing, structure of the microecosystem, and health benefits of kimchi.

Capsaicin: Current Understanding of Its Mechanisms and Therapy of Pain and Other Pre-Clinical and Clinical Uses

In this review, we discuss the importance of capsaicin to the current understanding of neuronal modulation of pain and explore the mechanisms of capsaicin-induced pain. We will focus on the analgesic effects of capsaicin and its clinical applicability in treating pain. Furthermore, we will draw attention to the rationale for other clinical therapeutic uses and implications of capsaicin in diseases such as obesity, diabetes, cardiovascular conditions, cancer, airway diseases, itch, gastric, and urological disorders.

Capsaicin and Its Role in Chronic Diseases

A significant number of experimental and clinical studies published in peer-reviewed journals have demonstrated promising pharmacological properties of capsaicin in relieving signs and symptoms of non-communicable diseases (chronic diseases). This chapter provides an overview made from basic and clinical research studies of the potential therapeutic effects of capsaicin, loaded in different application forms, such as solution and cream, on chronic diseases (e.g. arthritis, chronic pain, functional gastrointestinal disorders and cancer). In addition to the anti-inflammatory and analgesic properties of capsaicin largely recognized via, mainly, interaction with the TRPV1, the effects of capsaicin on different cell signalling pathways will be further discussed here. The analgesic, anti-inflammatory or apoptotic effects of capsaicin show promising results in arthritis, neuropathic pain, gastrointestinal disorders or cancer, since evidence demonstrates that the oral or local application of capsaicin reduce inflammation and pain in rheumatoid arthritis, promotes gastric protection against ulcer and induces apoptosis of the tumour cells. Sadly, these results have been paralleled by conflicting studies, which indicate that high concentrations of capsaicin are likely to evoke deleterious effects, thus suggesting that capsaicin activates different pathways at different concentrations in both human and rodent tissues. Thus, to establish effective capsaicin doses for chronic conditions, which can be benefited from capsaicin therapeutic effects, is a real challenge that must be pursued.

Anticarcinogenic activity of alpha-difluoromethylornithine, ginseng, eleutherococcus, and leuzea on radiation-induced carcinogenesis in female rats

PURPOSE

To carry out a comparative study of inhibition of radiation carcinogenesis using alpha-difluoromethylornithine (DFMO), tinctures of ginseng, eleutherococcus and leuzea in female rats.

MATERIALS AND METHODS

Locally bred female LIO-strain rats were subjected to a single whole body γ-irradiation dose of 4 Gy at 12 weeks of age. Modifying drugs were given with drinking water from the 10th day after irradiation until the end of the experiment (for 16 months).

RESULTS

Irradiated rats developed tumors 70.0-79.6% (malignant tumors: 43.7-45.0%) with a multiplicity of 1.48-1.75 (malignant: 0.5-0.58), while in unirradiated animals the incidence of all/malignant tumors was 21.9%/7.7% with multiplicity of 0.22/0.08. In exposed rats tumors most often developed in the mammary gland - 57.3%, reproductive and endocrine organs - 27.2%, and other localizations - 29.1%. All drugs, except leuzea, significantly reduced incidence and multiplicity of tumors, overall or at some localizations in irradiated rats. Highest, and practically equal inhibition, was shown by ginseng and DFMO, while eleutherococcus was clearly inferior. Ginseng reduced overall tumor incidence and multiplicity by 1.5 and 2.4 times, malignant tumor incidence and multiplicity - by 2.5 and 2.9 times, respectively.

CONCLUSIONS

The ginseng extract is the most promising radiation carcinogenesis inhibitor tested.

The two faces of capsaicin

Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide) is the principal pungent component in hot peppers, including red chili peppers, jalapeños, and habaneros. Consumed worldwide, capsaicin has a long and convoluted history of controversy about whether its consumption or topical application is entirely safe. Conflicting epidemiologic data and basic research study results suggest that capsaicin can act as a carcinogen or as a cancer preventive agent. Capsaicin is unique among naturally occurring irritant compounds because the initial neuronal excitation evoked is followed by a long-lasting refractory period, during which the previously excited neurons are no longer responsive to a broad range of stimuli. This process is referred to as desensitization and has been exploited for its therapeutic potential. Capsaicin-containing creams have been in clinical use for many years to relieve a variety of painful conditions. However, their effectiveness in pain relief is also highly debated and some adverse side effects have been reported. We have found that chronic, long-term topical application of capsaicin increased skin carcinogenesis in mice treated with a tumor promoter. These results might imply that caution should be exercised when using capsaicin-containing topical applications in the presence of a tumor promoter, such as, for example, sunlight.

Final report on the safety assessment of capsicum annuum extract, capsicum annuum fruit extract, capsicum annuum resin, capsicum annuum fruit powder, capsicum frutescens fruit, capsicum frutescens fruit extract, capsicum frutescens resin, and capsaicin

Capsicum-derived ingredients function as skin-conditioning agents--miscellaneous, external analgesics, flavoring agents, or fragrance components in cosmetics. These ingredients are used in 19 cosmetic products at concentrations as high as 5%. Cosmetic-grade material may be extracted using hexane, ethanol, or vegetable oil and contain the full range of phytocompounds that are found in the Capsicum annuum or Capsicum frutescens plant (aka red chiles), including Capsaicin. Aflatoxin and N-nitroso compounds (N-nitrosodimethylamine and N-nitrosopyrrolidine) have been detected as contaminants. The ultraviolet (UV) absorption spectrum for Capsicum Annuum Fruit Extract indicates a small peak at approximately 275 nm, and a gradual increase in absorbance, beginning at approximately 400 nm. Capsicum and paprika are generally recognized as safe by the U.S. Food and Drug Administration for use in food. Hexane, chloroform, and ethyl acetate extracts of Capsicum Frutescens Fruit at 200 mg/kg resulted in death of all mice. In a short-term inhalation toxicity study using rats, no difference was found between vehicle control and a 7% Capsicum Oleoresin solution. In a 4-week feeding study, red chilli (Capsicum annuum) in the diet at concentrations up to 10% was relatively nontoxic in groups of male mice. In an 8-week feeding study using rats, intestinal exfoliation, cytoplasmic fatty vacuolation and centrilobular necrosis of hepatocytes, and aggregation of lymphocytes in the portal areas were seen at 10% Capsicum Frutescens Fruit, but not 2%. Rats fed 0.5 g/kg day-1 crude Capsicum Fruit Extract for 60 days exhibited no significant gross pathology at necropsy, but slight hyperemia of the liver and reddening of the gastric mucosa were observed. Weanling rats fed basal diets supplemented with whole red pepper at concentrations up to 5.0% for up to 8 weeks had no pathology of the large intestines, livers, and kidneys, but destruction of the taste buds and keratinization and erosion of the gastrointestinal (GI) tract were noted in groups fed 0.5% to 5.0% red pepper. The results of 9-and 12-month extension of this study showed normal large intestines and kidneys. In rabbits fed Capsicum Annuum Powder at 5 mg/kg day-1 in the diet daily for 12 months damage to the liver and spleen was noted. A rabbit skin irritation test of Capsicum Annuum Fruit Extract at concentrations ranging from 0.1% to 1.0% produced no irritation, but Capsicum Frutescens Fruit Extract induced concentration-dependent (at 25 to 500 microg/ml) cytotoxicity in a human buccal mucosa fibroblast cell line. An ethanol extract of red chili was mutagenic in Salmonella typhimurium TA98, but not in TA100, or in Escherichia coli. Other genotoxicity assays gave a similar pattern of mixed results. Adenocarcinoma of the abdomen was observed in 7/20 mice fed 100 mg red chilies per day for 12 months; no tumors were seen in control animals. Neoplastic changes in the liver and intestinal tumors were observed in rats fed red chili powder at 80 mg/kg day-1 for 30 days, intestinal and colon tumors were seen in rats fed red chili powder and 1,2-dimethyl hydrazine, but no tumors were observed in controls. In another study in rats, however, red chile pepper in the diet at the same dose decreased the number of tumors seen with 1,2-dimethylhydrazine. Other feeding studies evaluated the effect of red chili peppers on the incidence of stomach tumors produced by N-methyl-N'-nitro-N-nitrosoguanidine, finding that red pepper had a promoting effect. Capsicum Frutescens Fruit Extract promoted the carcinogenic effect of methyl(acetoxymethyl)nitrosamine (carcinogen) or benzene hexachloride (hepatocarcinogen) in inbred male and female Balb/c mice dosed orally (tongue application). Clinical findings include symptoms of cough, sneezing, and runny nose in chili factory workers. Human respiratory responses to Capsicum Oleoresin spray include burning of the throat, wheezing, dry cough, shortness of breath, gagging, gasping, inability to breathe or speak, and, rarely, cyanosis, apnea, and respiratory arrest. A trade name mixture containing 1% to 5% Capsicum Frutescens Fruit Extract induced very slight erythema in 1 of 10 volunteers patch tested for 48 h. Capsicum Frutescens Fruit Extract at 0.025% in a repeated-insult patch test using 103 subjects resulted in no clinically meaningful irritation or allergic contact dermatitis. One epidemiological study indicated that chili pepper consumption may be a strong risk factor for gastric cancer in populations with high intakes of chili pepper; however, other studies did not find this association. Capsaicin functions as an external analgesic, a fragrance ingredient, and as a skin-conditioning agent--miscellaneous in cosmetic products, but is not in current use. Capsaicin is not generally recognized as safe and effective by the U.S. Food and Drug Administration for fever blister and cold sore treatment, but is considered to be safe and effective as an external analgesic counterirritant. Ingested Capsaicin is rapidly absorbed from the stomach and small intestine in animal studies. Subcutaneous injection of Capsaicin in rats resulted in a rise in the blood concentration, reaching a maximum at 5 h; the highest tissue concentrations were in the kidney and lowest in the liver. In vitro percutaneous absorption of Capsaicin has been demonstrated in human, rat, mouse, rabbit, and pig skin. Enhancement of the skin permeation of naproxen (nonsteroidal anti-inflammatory agent) in the presence of Capsaicin has also been demonstrated. Pharmacological and physiological studies demonstrated that Capsaicin, which contains a vanillyl moiety, produces its sensory effects by activating a Ca2 +-permeable ion channel on sensory neurons. Capsaicin is a known activator of vanilloid receptor 1. Capsaicin-induced stimulation of prostaglandin biosynthesis has been shown using bull seminal vesicles and rheumatoid arthritis synoviocytes. Capsaicin inhibits protein synthesis in Vero kidney cells and human neuroblastoma SHSY-5Y cells in vitro, and inhibits growth of E. coli, Pseudomonas solanacearum, and Bacillus subtilis bacterial cultures, but not Saccharomyces cerevisiae. Oral LD50 values as low as 161.2 mg/kg (rats) and 118.8 mg/kg (mice) have been reported for Capsaicin in acute oral toxicity studies, with hemorrhage of the gastric fundus observed in some of the animals that died. Intravenous, intraperitoneal, and subcutaneous LD50 values were lower. In subchronic oral toxicity studies using mice, Capsaicin produced statistically significant differences in the growth rate and liver/body weight increases. Capsaicin is an ocular irritant in mice, rats, and rabbits. Dose-related edema was observed in animals receiving Capsaicin injections into the hindpaw (rats) or application to the ear (mice). In guinea pigs, dinitrochlorobenzene contact dermatitis was enhanced in the presence of Capsaicin, injected subcutaneously, whereas dermal application inhibited sensitization in mice. Immune system effects have been observed in neonatal rats injected subcutaneously with Capsaicin. Capsaicin produced mixed results in S. typhimurium micronucleus and sister-chromatid exchange genotoxicity assays. Positive results for Capsaicin were reported in DNA damage assays. Carcinogenic, cocarcinogenic, anticarcinogenic, antitumorigenic, tumor promotion, and anti-tumor promotion effects of Capsaicin have been reported in animal studies. Except for a significant reduction in crown-rump length in day 18 rats injected subcutaneously with Capsaicin (50 mg/kg) on gestation days 14, 16, 18, or 20, no reproductive or developmental toxicity was noted. In pregnant mice dosed subcutaneously with Capsaicin, depletion of substance P in the spinal cord and peripheral nerves of pregnant females and fetuses was noted. In clinical tests, nerve degeneration of intracutaneous nerve fibers and a decrease in pain sensation induced by heat and mechanical stimuli were evident in subjects injected intradermally with Capsaicin. An increase in mean inspiratory flow was reported for eight normal subjects who inhaled nebulized 10(-7) M Capsaicin. The results of provocative and predictive tests involving human subjects indicated that Capsaicin is a skin irritant. Overall, studies suggested that these ingredients can be irritating at low concentrations. Although the genotoxicity, carcinogenicity, and tumor promotion potential of Capsaicin have been demonstrated, so have opposite effects. Skin irritation and other tumor-promoting effects of Capsaicin appear to be mediated through interaction with the same vanilloid receptor. Given this mechanism of action and the observation that many tumor promoters are irritating to the skin, the Panel considered it likely that a potent tumor promoter may also be a moderate to severe skin irritant. Thus, a limitation on Capsaicin content that would significantly reduce its skin irritation potential is expected to, in effect, lessen any concerns relating to tumor promotion potential. Because Capsaicin enhanced the penetration of an anti-inflammatory agent through human skin, the Panel recommends that care should be exercised in using ingredients that contain Capsaicin in cosmetic products. The Panel advised industry that the total polychlorinated biphenyl (PCB)/pesticide contamination should be limited to not more than 40 ppm, with not more than 10 ppm for any specific residue, and agreed on the following limitations for other impurities: arsenic (3 mg/kg max), heavy metals (0.002% max), and lead (5 mg/kg max). Industry was also advised that aflatoxin should not be present in these ingredients (the Panel adopted < or =15 ppb as corresponding to "negative" aflatoxin content), and that ingredients derived from Capsicum annuum and Capsicum Frutescens Plant species should not be used in products where N-nitroso compounds may be formed. (ABSTRACT TRUNCATED)

Medical Management of the Traumatic Consequences of Civil Unrest Incidents

In the context of this review, civil unrest is defined as disharmony, expressive dissatisfaction and/or disagreement between members of a community, which leads to a situation of competitive aggression that may find expression as disruption of organisation, conflicts, damage to property and injuries. Such a breakdown of harmonious relationships, which may result in property damage and human injuries that may be threatening to life, varies in magnitude from participation of a very few individuals up to the involvement of large crowds of people, which may evolve into a full-scale riot. It is the latter situation often involving demonstrators, opposing groups and law enforcement personnel that can result in multiple casualties and present a very significant challenge to the resources of local healthcare institutions. The causation of civil unrest incidents is multifactorial and has generic, specific and potentiating elements. With the current national and international societal, political and discriminatory problems, it is likely that civil unrest incidents on both small and large scales will continue to occur at a high and possibly increasing rate on a worldwide basis, and for these not infrequent incidents, the medical community should be in a state of informed preparation. The circumstances of civil unrest incidents are very variable with respect to causation, overall magnitude, frequency, timing, geographical location, numbers of persons involved, demographics of participants, influence of extremists, confrontation with opposing groups and control measures used by law enforcement agencies. Methods used by police and security forces for the control of civil unrest incidents, if advanced negotiations with organisers and verbal warnings have failed, fall basically into two categories: physical and chemical measures. Physical methods include restraint holds, truncheons, batons, mounted horses, projectiles (such as bean bags, plastic and rubber bullets), water cannons, tasers and (rarely) live ammunition. All of these physical measures are associated with pain and immobilisation, and there is a high potential for soft tissue and bone injuries. Some of the more severe physical methods, including plastic and rubber bullets, may cause lethal injuries. The basis for using chemicals in civil unrest incidents is that they cause distraction, transient harassment and incapacitation, temporary impairment of the conduct of coordinated tasks and cause a desire to vacate the area of unrest. Although screening smokes and malodors have sometimes been employed, the major group of chemicals used are peripheral chemosensory irritants (PCSIs), which reversibly interact with sensory nerve receptors in exposed skin and mucosal surfaces, resulting in the production of local uncomfortable sensations and associated reflexes. Major effects are on the eye, respiratory tract and (to a lesser degree) skin. Thus, the induced transient pain and discomfort in the eye, respiratory tract and skin, together with associated lacrimation, blepharospasm, rhinorrhoea, sialorrhoea, cough and breathing difficulties, produce temporary incapacitation and interference with the conduct of coordinated tasks, and form the basis for harassment of malefactors. Currently used peripheral chemosensory irritants are 1-chloroacetophenone, 2-chlorobenzylidene malononitrile, dibenz(b.f)-1,4-oxazepine, oleoresin capsicum and pelargonic acid vanillylamide. Depending on operational circumstances, irritants may be dispersed as a smoke, powder cloud, aerosol, vapour, or in solution; the mode of generation and dispersion of irritant can influence hazard. Brief acute exposure to chemosensory irritants produces effects that generally resolve within an hour, leaving no long-term sequelae. However, sustained exposure to high concentrations may produce tissue injury, notably to the eye, respiratory tract and skin. With solutions of sensory irritants, other formulation constituents may enhance PCSI toxicity or introduce additional local and/or systemic toxicity. By the very circumstances of civil unrest incidents, injuries are inevitable, particularly when emotions are heightened and police and security forces have to resort to various chemical and/or physical means of control. Trauma may include slight to severe physical and/or chemical injuries, psychological problems and occasional deaths. Hospitals should be prepared for a wide range of casualties, and the fact that those seeking help will constitute a heterogeneous group, including wide age range, male, female, and individuals with pre-existing ill health. A major civil unrest incident necessitates that the local receiving hospital should be prepared and equipped for decontamination and triage processes. It is necessary to reassure patients who have been exposed to sensory irritants that the signs and symptoms are rapidly reversible, and do not result in long-term sequelae. With respect to chemical exposures, detailed evaluation should be given to possible ocular, cutaneous, respiratory and gastrointestinal effects. Also, exposure to chemosensory irritants results in transient increases in blood pressure, bradycardia and increased intraocular pressure. This indicates that those with cardiovascular diseases and glaucoma may be at increased risk for the development of complications. This article details the pharmacological, toxicological and clinical effects of chemicals used in civil disturbance control and discusses the management of contaminated individuals. Additionally, the potential for adverse effects from delivery systems and other physical restraint procedures is summarised. Due to the emergency and specialised circumstances and conditions of a civil unrest incident, there is a clear need for advanced planning by healthcare institutions in the event that such an incident occurs in their catchment area. This should include ensuring a good information base, preparations for medical and support staff readiness, and availability of required equipment and medications. Ideally, planning, administration and coordination should be undertaken at both local (regional) and central (governmental) centres. Regional centres should have responsibilities for education, training, ensuring facilities and staffing are appropriate, and that adequate equipment and medicines are available. There should be cooperative interactions and communications with local police and other emergency services. Centrally directed functions should include ensuring adequacy of the information base, coordinating activities and agreeing approaches between the regional centres, and periodic audits of regional centres with respect to the staffing, facility, equipment and training needs. Also, there is a need for most countries to introduce detailed guidelines and formal (regulatory) schemes for the assessment of the safety-in-use of chemicals and the delivery systems that are to be used against heterogeneous human populations for the control of civil unrest incidents. Such regulatory approval schemes should also cover advisory functions for safe use and any required restrictions.

Effects of dietary intake and genetic factors on hypermethylation of the hMLH1 gene promoter in gastric cancer

AIM: Hypermethylation of the promoter of the hMLH1 gene, which plays an important role in mismatch repair during DNA replication, occurs in more than 30% of human gastric cancer tissues. The purpose of this study was to investigate the effects of environmental factors, genetic polymorphisms of major metabolic enzymes, and microsatellite instability on hypermethylation of the promoter of the hMLH1 gene in gastric cancer.

METHODS: Data were obtained from a hospital-based, case-control study of gastric cancer. One hundred and ten gastric cancer patients and 220 age- and sex-matched control patients completed a structured questionnaire regarding their exposure to environmental risk factors. Hypermethylation of the hMLH1 gene promoter, polymorphisms of the GSTM1, GSTT1, CYP1A1, CYP2E1, ALDH2 and L-myc genes, microsatellite instability and mutations of p53 and Ki-ras genes were investigated.

RESULTS: Both smoking and alcohol consumption were associated with a higher risk of gastric cancer with hypermethylation of the hMLH1 gene promoter. High intake of vegetables and low intake of potato were associated with increased likelihood of gastric cancer with hypermethylation of the hMLH1 gene promoter. Genetic polymorphisms of the GSTM1, GSTT1, CYP1A1, CYP2E1, ALDH2, and L-myc genes were not significantly associated with the risk of gastric cancer either with or without hypermethylation in the promoter of the hMLH1 gene. Hypermethylation of the hMLH1 promoter was significantly associated with microsatellite instability (MSI): 10 of the 14 (71.4%) MSI-positive tumors showed hypermethylation, whereas 28 of 94 (29.8%) the MSI-negative tumors were hypermethylated at the hMLH1 promoter region. Hypermethylation of the hMLH1 gene promoter was significantly inversely correlated with mutation of the p53 gene.

CONCLUSION: These results suggest that cigarette smoking and alcohol consumption may influence the development of hMLH1-positive gastric cancer. Most dietary factors and polymorphisms of GSTM1, GSTT1, CYP1A1, CYP2E1, ALDH2, and L-myc genes are not independent risk factors for gastric cancer with hyperme-thylation of the hMLH1 promoter. These data also suggest that there could be two or more different molecular pathways in the development of gastric cancer, perhaps involving tumor suppression mechanisms or DNA mismatch repair.

Kimchi and soybean pastes are risk factors of gastric cancer

AIM

This case-control study investigated the effects of kimchi, soybean paste, fresh vegetables, nonfermented alliums, nonfermented seafood, nonfermented soybean foods, and the genetic polymorphisms of some metabolic enzymes on the risk of gastric cancer in Koreans.

METHODS

We studied 421 gastric cancer patients and 632 age- and sex-matched controls. Subjects completed a structured questionnaire regarding their food intake pattern. Polymorphisms of cytochrome P450 1A1 (CYP1A1), cytochrome P450 2E1 (CYP2E1), glutathione S-transferase mu 1 (GSTM1), glutathione S-transferase theta 1 (GSTT1) and aldehyde dehydrogenase 2 (ALDH2) were investigated.

RESULTS

A decreased risk of gastric cancer was noted among people with high consumption of nonfermented alliums and nonfermented seafood. On the other hand, consumption of kimchi, and soybean pastes was associated with increased risk of gastric cancer. Individuals with the CYP1A1 Ile/Val or Val/Val genotype showed a significantly increased risk for gastric cancer. Increased intake of kimchi or soybean pastes was a significant risk factor for the CYP1A1 Ile/Ile, the CYP2E1 c1/c1, the GSTM1 non-null, the GSTT1 non-null, or the ALDH2 *1/*1 genotype. In addition, eating soybean pastes was associated with the increased risk of gastric cancer in individuals with the GSTM1 null type. Nonfermented alliums were significant in individuals with the CYP1A1 Ile/Ile, the CYP2E1 c1/c2 or c2/c2, the GSTT1 null, the GSTT1 non-null, or the ALDH2 *1/*2 or *2/*2 genotype, nonfermented seafood was those with the CYP1A1 Ile/Ile, the CYP2E1 c1/c1, the ALDH2 *1/*1 genotype or any type of GSTM1 or GSTT1. In homogeneity tests, the odds ratios of eating kimchi for gastric cancer according to the GSTM1 or GSTT1 genotype were not homogeneous.

CONCLUSION

Kimchi, soybean pastes, and the CYP1A1 Ile/Val or Val/Val are risk factors, and nonfermented seafood and alliums are protective factors against gastric cancer in Koreans. Salt or some chemicals contained in kimchi and soybean pastes, which are increased by fermentation, would play important roles in the carcinogenesis of stomach cancer. Polymorphisms of the CYP1A1, CYP2E1, GSTM1, GSTT1, and ALDH2 genes could modify the effects of some environmental factors on the risk of gastric cancer.

A prospective cohort study of soy product intake and stomach cancer death

The relationship between intake of soy products and death from stomach cancer was examined in a community-based prospective study of Japanese men and women in Takayama, Japan. Over 7 years of follow-up, 121 deaths from stomach cancer (81 men and 40 women) occurred among 30,304 (13,880 men and 16,424 women) participants who were at least 35 years of age. Diet including the intake of soy products and isoflavones was assessed by a validated semiquantitative food-frequency questionnaire at the beginning of the study. In men, the highest compared to the lowest tertile of total soy product intake was significantly inversely associated with death from stomach cancer after controlling for covariates (hazard ratios=0.50; 95% confidence intervals (CIs) 0.26-0.93, P for trend=0.03). Decreased hazard ratios for the highest compared to the lowest tertiles of total soy product intake (hazard ratios=0.49; 95% CI 0.22-1.13) was observed in women, although this association was of marginal significance. These data suggest that soy intake may reduce the risk of death from stomach cancer.

Dietary factors and gastric cancer in Korea: a case-control study

To assess gastric cancer (GC) risk in relation to dietary intake in Korea, a case-control study was performed. Trained dietitians interviewed 136 patients diagnosed with GC, and the same number of controls were selected by matching sex, age and hospital. A significant decrease in GC risk was observed with increased intake of Baiechu kimchi (prepared with salted Chinese cabbage and red pepper, etc.), Baiechu kimchi-stew, garlic, mushroom and soybean milk. On the contrary, a significant increase in the risk of GC was observed with increased intake of cooked rice with bean, charcoal grilled beef, pollack soup, Kkakduki (a kind of kimchi prepared with salted radish and red pepper, etc.), Dongchimi (a kind of kimchi prepared with radish and a large quantity of salt water) and cooked spinach. In food groups, increased intake of soybean products was associated with decreased risk of GC. Intake of citrus fruits rather than total fruits was shown to have a protective effect on the risk of GC, but was not significant. In this study, intake of total vegetables was shown to have a protective effect, whereas high nitrate-containing vegetables increased the risk of GC. In conclusion, our study suggests that the risk of GC decreased with high consumption of fresh vegetables and fruits, whereas high consumption of foods rich in nitrate and carcinogenic substances produced during the cooking process increased the risk of GC.

Riot control agents: pharmacology, toxicology, biochemistry and chemistry

The desired effect of all riot control agents is the temporary disablement of individuals by way of intense irritation of the mucous membranes and skin. Generally, riot control agents can produce acute site-specific toxicity where sensory irritation occurs. Early riot control agents, namely, chloroacetophenone (CN) and chlorodihydrophenarsazine (DM), have been replaced with 'safer' agents such as o-chlorobenzylidene malononitrile (CS) and oleoresin of capsicum (OC). Riot control agents are safe when used as intended: however, the widespread use of riot control agents raises questions and concerns regarding their health effects and safety. A large margin exists between dosages that produce harassment and dosages likely to cause adverse health effects for modern riot control agents such as CS and dibenz[b,f]1 : 4-oxazepine (CR). Yet, despite the low toxicity of modern riot control agents, these compounds are not entirely without risk. The risk of toxicity increases with higher exposure levels and prolonged exposure durations. Ocular, pulmonary and dermal injury may occur on exposure to high levels of these substances, and exposure to riot control agents in enclosed spaces may produce significant toxic effects. Reported deaths are few involving riot control agents, and then only under conditions of prolonged exposure and high concentrations. Recently, concern has focused on the deaths resulting from law enforcement use of OC, a riot control agent generally regarded as safe because it is a natural product. As with other xenobiotics, not enough is known concerning the long-term/chronic effects of riot control agents. Clearly, there is considerable need for additional research to define and delineate the biological and toxicological actions of riot control agents and to illuminate the full health consequences of these compounds as riot control agents.

17Beta-estradiol modulates gastroduodenal preneoplastic alterations in rats exposed to the carcinogen N-methyl-N'-nitro-nitrosoguanidine

Gastric cancers are a significant cause of morbidity worldwide. Epidemiological studies and animal models show that males have higher incidences of gastric cancers compared with females, suggesting that sex hormones may modulate gastric cancer risk. An animal model of the initiation phase of gastric cancer was used to determine the effects of systemic estrogen administration on morphological progression of preneoplastic lesions and to define cell populations at which estrogens may act. Preneoplastic progression in antral and duodenal mucosa was examined in male rats that received the chemical carcinogen, N-methyl-N'-nitro-nitrosoguanidine (MNNG), during treatment with implants containing 17beta-estradiol or oil vehicle. Histopathological changes in antral and duodenal gland morphology, numbers of proliferating cells and apoptotic bodies, and antral gastrin cell numbers and protein storage levels were determined 4 weeks later. With MNNG treatment, duodenal villous heights were significantly decreased, and epithelial cells displayed histological features of hyperplasia and dysplasia. Antral glands showed epithelial hyperplasia and dysplasia, increased mucosal height, and decreased mucin levels. Antral gastrin storage protein levels were decreased by MNNG. Systemic treatment with 17beta-estradiol significantly reversed MNNG-induced alterations in duodenal gland heights while increasing mucin and gastrin levels in antral glands. Cell proliferation and apoptosis rates were not significantly different between groups. The present results indicate that systemic 17beta-estradiol treatment influences antral and duodenal gland differentiation during the initiation phase of chemical gastroduodenal carcinogenesis in male rats. These results explain, in part, a potential pathway through which protective effects of estrogens on chemical carcinogenesis are mediated in the upper gastrointestinal tract.

Effects of capsaicin on induction of c-jun proto-oncogene expression in Fisher-344 rats by N-methyl-N'-nitro-N-nitrosoguanidine

N-Methyl-N'-nitro-N-nitrosoguanidine (MNNG) is a potent inducer of cellular stress leading to chromosomal aberrations, point mutations, and cell death. To study the effect of capsaicin on c-jun expression when given with MNNG to rats, Fisher-344 rats that had been administered MNNG were treated with capsaicin in their diet and organs were removed for measuring c-jun transcripts. We show that pre- or post-treatment of capsaicin relative to MNNG administration up- or down-regulates (depending on the organ) c-jun expression in a consistent pattern in most organs. In fact, we found in this study that capsaicin inhibits c-jun induction, stimulated by MNNG, in the spleen, heart, stomach and lung. Since MNNG, a methylating agent, is a powerful carcinogen that is very effective in the induction of c-jun mRNA, the results suggest that capsaicin uptake in the diet could play a role in inhibition of tumorigenesis induced by MNNG.

Capsaicin in hot chili pepper: carcinogen, co-carcinogen or anticarcinogen?

Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide) is a major pungent ingredient of the Capsicum fruits such as hot green and red peppers. Besides its use as a food additive in various spicy cuisines, capsaicin is currently utilized for therapeutic purposes to treat various peripheral painful conditions such as rheumatoid arthritis and diabetic neuropathy. Considering consumption of capsaicin as a food additive and its current medicinal application in humans, correct evaluation and precise assessment of any harmful effects of this compound are essential from the public health standpoint. Numerous investigations have been conducted to determine the potential mutagenic and carcinogenic activity of capsaicin and chili pepper, but results are discordant. This review briefly examines findings in the literature of studies testing mutagenicity and tumorigenicity of capsaicin and presents a possible mechanistic basis for the dual effects exerted by the compound.

Capsaicin, a double-edged sword: toxicity, metabolism, and chemopreventive potential

Capsaicin (8-methyl-N-vanillyl-6-nonenamide) is a primary pungent and irritating principle present in chilies and red peppers which are widely used as spices. Because of its selective effects on the functions of a defined subpopulation of sensory neurons, capsaicin is currently used as a versatile tool for the study of pain mechanisms and also for pharmacotherapy to treat several pain disorders. Considering the frequent consumption of capsaicin as a food additive and its current medicinal use, correct assessment of hazardous effects of this compound is important. Mutagenic and carcinogenic activities of capsaicin and chili extracts have been studied, but results are conflicting. Mammalian metabolism of capsaicin has been also reported. Capsaicin appears to interact with xenobiotic metabolizing enzymes, particularly microsomal cytochrome P450-dependent monooxygenases which are involved in activation as well as detoxification of various chemical carcinogens and mutagens. Recent studies have shown that hepatic cytochrome P450 2E1 catalyzes the conversion of capsaicin to reactive species such as the phenoxy radical intermediate capable of covalently binding to the active site of the enzyme as well as tissue macromolecules. While covalent modification of protein and nucleic acids leads to toxicity including necrosis, mutagenesis, and carcinogenesis, suicidal inhibition of microsomal cytochrome P450 may prohibit further activation of capsaicin and also of other toxic xenobiotics. Results from recent studies indicate that capsaicin possesses the chemoprotective activity against some chemical carcinogens and mutagens.

Soy intake and cancer risk: a review of the in vitro and in vivo data

International variations in cancer rates have been attributed, at least in part, to differences in dietary intake. Recently, it has been suggested that consumption of soyfoods may contribute to the relatively low rates of breast, colon, and prostate cancers in countries such as China and Japan. Soybeans contain a number of anticarcinogens, and a recent National Cancer Institute workshop recommended that the role of soyfoods in cancer prevention be investigated. In this review, the hypothesis that soy intake reduces cancer risk is considered by examining relevant in vitro, animal, and epidemiological data. Soybeans are a unique dietary source of the isoflavone genistein, which possesses weak estrogenic activity and has been shown to act in animal models as an antiestrogen. Genistein is also a specific inhibitor of protein tyrosine kinases; it also inhibits DNA topoisomerases and other critical enzymes involved in signal transduction. In vitro, genistein suppresses the growth of a wide range of cancer cells, with IC50 values ranging from 5 to 40 microM (1-10 micrograms/ml). Of the 26 animal studies of experimental carcinogenesis in which diets containing soy or soybean isoflavones were employed, 17 (65%) reported protective effects. No studies reported soy intake increased tumor development. The epidemiological data are also inconsistent, although consumption of nonfermented soy products, such as soymilk and tofu, tended to be either protective or not associated with cancer risk; however, no consistent pattern was evident with the fermented soy products, such as miso. Protective effects were observed for both hormone- and nonhormone-related cancers. While a definitive statement that soy reduces cancer risk cannot be made at this time, there is sufficient evidence of a protective effect to warrant continued investigation.

Suppressive effect of wasabi (pungent Japanese spice) on gastric carcinogenesis induced by MNNG in rats

Dietary habits have been causally implicated in gastric carcinogenesis, whereas minor dietary items may also play a part. Wasabi is a popular pungent spice in Japanese meals. In this study the effect of wasabi on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced gastric carcinogenesis was studied in rats. Wistar WKY male rats received drinking water containing 50 micrograms/ml of MNNG or tap water alone and a basal diet (PCE-2) or PCE-2 containing 10% (wt/wt) of wasabi powder for 40 weeks. Thus, three groups were completed as MNNG + PCE-2 (n = 30), MNNG + wasabi (n = 30), and tap water + wasabi (n = 30). At autopsy, nine rats (30%) had seven glandular stomach tumors (2 adenocarcinomas, 2 adenomatous polyps, and 3 adenomatous glandular hyperplasias) and three duodenal adenocarcinomas in the MNNG + PCE-2 group, whereas in the MNNG + wasabi group, two rats (7%) had one forestomach epidermoid cyst and one duodenal carcinosarcoma (corrected chi 2 = 4.63, p less than 0.05 for incidences of glandular stomach tumors between 2 groups). In addition, two rats had microscopic atypical glands in the MNNG + PCE-2 group. There was no tumor in the tap water + wasabi group. These results indicated that glandular stomach carcinogenesis induced by MNNG was suppressed by the administration of wasabi.