Multiplex Immunoassay Techniques for On-Site Detection of Security Sensitive Toxins

Biological toxins are a heterogeneous group of high molecular as well as low molecular weight toxins produced by living organisms. Due to their physical and logistical properties, biological toxins are very attractive to terrorists for use in acts of bioterrorism. Therefore, among the group of biological toxins, several are categorized as security relevant, e.g., botulinum neurotoxins, staphylococcal enterotoxins, abrin, ricin or saxitoxin. Additionally, several security sensitive toxins also play a major role in natural food poisoning outbreaks. For a prompt response to a potential bioterrorist attack using biological toxins, first responders need reliable, easy-to-use and highly sensitive methodologies for on-site detection of the causative agent. Therefore, the aim of this review is to present on-site immunoassay platforms for multiplex detection of biological toxins. Furthermore, we introduce several commercially available detection technologies specialized for mobile or on-site identification of security sensitive toxins.     

Toxicological interactions between alcohol and benzodiazepines

BACKGROUND: We review recentfindings on the toxicological interactions between alcohol (ethanol) and benzodiazepines, and the combined use of benzodiazepines and alcohol in fatal poisoning. Acute ingestion of alcohol combined with benzodiazepines is responsible for several toxicological interactions that can have significant clinical implications. In general, metabolism of these drugs is delayed when combined with acute alcohol ingestion although some reports suggest otherwise. Alternately, the drugs metabolized during chronic alcohol ingestion have an increased clearance. The net effect may also be influenced by internal (e.g., disease, age) and external (e.g., environment, diet) factors. Fatal poisoning involving coadministration of alcohol and benzodiazepine, especially triazolam, continues to be a serious problem.     

Epidemiological application of early markers of nephrotoxicity

This paper is a review of epidemiological studies in which sensitive markers of nephrotoxicity have been used to detect the early effects of chemicals on the kidney. Most of the studies are cross-sectional, and their objective was either to identify potentially nephrotoxic chemicals (organic solvents, heavy metals) in the working or general environment or to establish dose-response/effect relationships from which safe exposure levels can be defined (e.g., for cadmium and mercury vapour). A few longitudinal studies were conducted to determine the persistence of renal disturbances and to get information on their predictive value (e.g., microproteinuria in cadmium workers). Nephrotoxicity tests, which have proved to be the most useful in these epidemiological studies, rely on the determination of specific urinary proteins which, according to their size, reflect the functional integrity of the proximal tubule (e.g., retinol-binding protein or beta 2-microglobulin) or the glomerulus (e.g., albumin, immunoglobulin G). An increased urinary excretion of the lysosomal enzyme N-acetyl-beta-D-glucosaminidase has been reported in several studies (e.g., in lead-exposed workers), but the pathological significance of this finding remains to be clarified, particularly when it is not associated with changes in the urinary excretion of specific proteins. Further work is needed to assess the usefulness of tests introduced more recently such as the assay of renal antigens in urine and the use of red-blood-cell membrane negative charges as an index of the glomerular polyanion. With the exception of microproteinuria observed in chronic cadmium poisoning, no epidemiological data are available on the prognostic value of subclinical renal effects caused by nephrotoxic chemicals.     

解藻朊酸弧菌食物中毒1起流行病学调查

目的对南通市某区1起因农村家宴引起的解藻朊酸弧菌食物中毒进行凋查分析,为该类食物中毒处理、防治提供参考。方法对该起食物中毒进行现场卫生学调查、流行病学凋查,对采集标本进行实验室分离培养,通过统计学处理和病例对照分析,找出食物中毒原因并提出针对性防治对策。结果综合现场卫生学调查、流行病学调查、实验室培养结果,确定该起食物中毒为1起解藻朊酸弧菌食物中毒,中毒原因可能为切菜刀、砧板生熟不分,食物加工不彻底。结论解藻朊酸弧菌与副溶血性弧菌生物特性相似,本地既往从未有相关报道,各地对解藻朊酸弧菌食物中毒报道也很少,卫生行政部门及疾控机构应加强对该类食物中毒的鉴别和研究,做好该类食物中毒的防治工作。     

Histamine poisoning (scombroid fish poisoning): an allergy-like intoxication

Histamine poisoning results from the consumption of foods, typically certain types of fish and cheeses, that contain unusually high levels of histamine. Spoiled fish of the families, Scombridae and Scomberesocidae (e.g. tuna, mackerel, bonito), are commonly implicated in incidents of histamine poisoning, which leads to the common usage of the term, "scombroid fish poisoning", to describe this illness. However, certain non-scombroid fish, most notably mahi-mahi, bluefish, and sardines, when spoiled are also commonly implicated in histamine poisoning. Also, on rare occasions, cheeses especially Swiss cheese, can be implicated in histamine poisoning. The symptoms of histamine poisoning generally resemble the symptoms encountered with IgE-mediated food allergies. The symptoms include nausea, vomiting, diarrhea, an oral burning sensation or peppery taste, hives, itching, red rash, and hypotension. The onset of the symptoms usually occurs within a few minutes after ingestion of the implicated food, and the duration of symptoms ranges from a few hours to 24 h. Antihistamines can be used effectively to treat this intoxication. Histamine is formed in foods by certain bacteria that are able to decarboxylate the amino acid, histidine. However, foods containing unusually high levels of histamine may not appear to be outwardly spoiled. Foods with histamine concentrations exceeding 50 mg per 100 g of food are generally considered to be hazardous. Histamine formation in fish can be prevented by proper handling and refrigerated storage while the control of histamine formation in cheese seems dependent on insuring that histamine-producing bacteria are not present in significant numbers in the raw milk.     

Food additives.

The use of additives to food fulfils many purposes, as shown by the index issued by the Codex Committee on Food Additives: Acids, bases and salts; Preservatives, Antioxidants and antioxidant synergists; Anticaking agents; Colours; Emulfifiers; Thickening agents; Flour-treatment agents; Extraction solvents; Carrier solvents; Flavours (synthetic); Flavour enhancers; Non-nutritive sweeteners; Processing aids; Enzyme preparations. Many additives occur naturally in foods, but this does not exclude toxicity at higher levels. Some food additives are nutrients, or even essential nutritents, e.g. NaCl. Examples are known of food additives causing toxicity in man even when used according to regulations, e.g. cobalt in beer. In other instances, poisoning has been due to carry-over, e.g. by nitrate in cheese whey - when used for artificial feed for infants. Poisonings also occur as the result of the permitted substance being added at too high levels, by accident or carelessness, e.g. nitrite in fish. Finally, there are examples of hypersensitivity to food additives, e.g. to tartrazine and other food colours. The toxicological evaluation, based on animal feeding studies, may be complicated by impurities, e.g. orthotoluene-sulfonamide in saccharin; by transformation or disappearance of the additive in food processing in storage, e.g. bisulfite in raisins; by reaction products with food constituents, e.g. formation of ethylurethane from diethyl pyrocarbonate; by metabolic transformation products, e.g. formation in the gut of cyclohexylamine from cyclamate. Metabolic end products may differ in experimental animals and in man: guanylic acid and inosinic acid are metabolized to allantoin in the rat but to uric acid in man. The magnitude of the safety margin in man of the Acceptable Daily Intake (ADI) is not identical to the "safety factor" used when calculating the ADI. The symptoms of Chinese Restaurant Syndrome, although not hazardous, furthermore illustrate that the whole ADI cannot always be ingested as a single dose on an empty stomach with impunity.     

Pharmacological applications of inorganic complexes.

Inorganic complexes have long been utilized for many therapeutic purposes. They were used or tried, perhaps because of the general notion that inorganic compounds (e.g., metal complexes) are toxic and a controlled use of such a compound may suppress some biological process. In this review, we briefly outline the properties of several selected groups of inorganic complexes and how they can affect biological systems and contribute to human pathologies.     

Pharmaceutical excipient development: the need for preclinical guidance

Pharmaceutical excipients have a vital role in drug formulations, a role that has tended to be neglected as evidenced by the lack of mechanisms to assess excipient safety outside a new drug application process. Currently, it is assumed that an excipient is "approved" when the new drug formulation, of which it is a constituent, receives regulatory acceptance. Existing regulations and guidelines indicate that new (novel) excipients should be treated as new chemical entities with full toxicological evaluation. No guidance is available for potentially useful materials (essentially new excipients) available from other industries, e.g., food additives or for established excipients with a new application, e.g., dose route change. However, despite this situation, drug companies are actively evaluating new materials or applying new uses to established excipients. Recently developed excipients (e.g., materials giving "sugar-free" status to medical preparations, the cyclodextrins, and the hydrofluoroalkane inhalation propellants) and excipients undergoing development (e.g., chitosan, various enteric coating substances, liposomes, polymers derived from glycolic and lactic acids, and vaccine adjuvants) are all discussed. In light of many other areas of drug development having recently benefited from new or updated regulatory guidance, specific guidance to assist companies in the development of their excipients is urgently needed. Also, an excipient testing strategy would be an excellent topic for inclusion for International Conference on Harmonisation (ICH) consideration. Such guidance/discussion would complement the current advances in pharmacopoeial standardization of excipient quality. As a consequence, it may be possible to have excipients reviewed by a committee of an international pharmacopoeia with the safety data assessed by elected experts and published.     

Naturally Occurring Seafood Toxins

Abstract

Incidents of illness reported to the Centers for Disease Control (CDC) in the period 1978–1987 were limited to ciguatera, scombroid fish poisoning (SFP), and paralytic shellfish poisoning (PSP). Natural intoxications are both highly regional and species associated, and toxins are present in seafood at the time of capture.

Ciguatera is a sometimes severe disease caused by consuming certain species of fish, usually island or reef, from tropical, subtropical, and other (temperate) waters, and was responsible for about half of all reported outbreaks to the CDC. Treatments are largely supportive, and mortality is usually low. Controls based on regulation of fishing or marketling of dangerous species, supported by testing suspect fish and educating consumers, sports fishers and health professionals, are recommended.

SFP caused nearly the same number of outbreaks as ciguatera, but was much more widespread. Tuna, mahimahi and bluefish are implicated as the major cause of SFP. The disease is generally mild and self-resolving, and symptoms can often be ameliorated by certain antihistamine drugs. Because the histamine poisoning is produced due to improper temperature control after the fish is caught, the disease can be prevented by rapid cooling and holding fish at low temperature(s) before cooking, as well as by not leaving the fish out too long when serving it under inadequate terperature control. A Hazard Analysis Critical Control Point-based system, and the education of subsistence and recreational/commercial fishers and cooks/servers may control this poisoning.

Paralytic shellfish poisoning was reported to the CDC as a minor cause of illness, with only two deaths. Although “other” natural seafood intoxications (e.g., puffer fish poisoning, and neurotoxic, diarrhetic and amnesic shellfish poisoning) have not been widely reported in U.S. consumers, the potential for their occurrence either from domestic or imported seafoods from imports is real. Increased vigilance concerning imported product, testing for these “other” toxins, and procedures to deal with outbreaks are needed.     

Human Body Burden of Polychlorinated Dibenzofurans Associated with Toxicity Based on the Yusho and Yucheng Incidents

Human Body Burden of Polychlorinated Dibenzofurans Associatedwith Toxicity Based on the Yusho and Yucheng Incidents. RYAN,J. J., GASIEWICZ, T. A., AND BROWN, J. F., JR. (1990). FundamAppl. Toxicol. 15, 722–731. The polychlorinated dibenzofurans(PCDFs) are one group of man-made toxicants for which reasonablyextensive data exist relevant to dose-response relationshipsin humans. Examination of contaminated food oil consumptionfrom the yusho (Japan) poisoning incident indicates the meanuptake or body burden of 2,3,4,7,8-pentachlorodibenzofuran (PnCDF)equivalents (PEQ) associated with nausea and anorexia to be4.4 µg/kg body wt and that associated with chloracne tobe 5.9 µg/kg. For the yucheng (Taiwan) poisoning incident,blood measurements for chloracne show a similar body burdenof 4.0 µg/kg. The latter value is toxicologically equivalentto a 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalent (TEQ) bodyburden of 2.0 µg/kg body wt or about 150 µg foran adult person. This corresponds to an adipose tissue levelof about 10 µg/kg fat, and is comparable to that knownto cause chloracne in rhesus monkeys. These body burdens ona TEQ basis are more than 200 times higher than the averagecurrent levels of PCDDs/PCDFs found in North American populationsand are the first to relate human body burdens of PCDFs witha known effect and to compare them to animal data. Since theeffects reported may not be the most sensitive indicator ofhuman toxicity, lower body burdens could be associated withmore subtle toxicological events.     

Emerging trends of nanoparticles application in food technology: Safety paradigms

Nanotechnology has expanded its wings in various spheres of life. It has progressed from first-generation passive nanomaterial to active nanotechnology (e.g., drug delivery) and nanosystems (e.g., robotics). Although nanofood is still in its infancy; however, these particles are now finding application as a carrier of antimicrobial polypeptides required against microbial deterioration of food quality in the food industry. Another challenging area is nanoencapsulation of pesticides that releases the pesticides within the stomach of the insect, thus minimizing contamination of crops and vegetables. The current nanotechnology applications in food science provide the detection of food pathogens, through nanosensors, which are quick, sensitive and less labour-intensive procedures. With the increasing health consciousness among consumers, it is possible to use nanosensors in plastic packaging to detect gases released due to food spoilage. However, it is well known that the nanoparticles equipped with new chemical and physical properties that vary from normal macro particles of the same composition may interact with the living systems thereby causing unexpected toxicity. Limited toxicological/safety assessments have been carried out for a few nanoparticles; hence studies relevant to oral exposure risk assessment are required for particles to be used in food.     

Symptoms and implications of selenium toxicity in fish: the Belews Lake case example

Belews Lake, North Carolina was contaminated by selenium in wastewater from a coal-fired power plant during the mid-1970s, and toxic impacts to the resident fish community (20 species) were studied for over two decades. Symptoms of chronic selenium poisoning in Belews Lake fish included, (1) telangiectasia (swelling) of gill lamellae; (2) elevated lymphocytes; (3) reduced hematocrit and hemoglobin (anemia); (4) corneal cataracts; (5) exopthalmus (popeye); (6) pathological alterations in liver, kidney, heart, and ovary (e.g. vacuolization of parenchymal hepatocytes, intracapillary proliferative glomerulonephritis, severe pericarditis and myocarditis, necrotic and ruptured mature egg follicles); (7) reproductive failure (reduced production of viable eggs due to ovarian pathology, and post-hatch mortality due to bioaccumulation of selenium in eggs); and (8) teratogenic deformities of the spine, head, mouth, and fins. Important principles of selenium cycling and toxicity were documented in the Belews Lake studies. Selenium poisoning in fish can be 'invisible', because, the primary point of impact is the egg, which receives selenium from the female's diet (whether consumed in organic or inorganic forms), and stores it until hatching, whereupon it is metabolized by the developing fish. If concentrations in eggs are great enough (about 10 microg/g or greater) biochemical functions may be disrupted, and teratogenic deformity and death may occur. Adult fish can survive and appear healthy despite the fact that extensive reproductive failure is occurring--19 of the 20 species in Belews Lake were eliminated as a result of this insidious mode of toxicity. Bioaccumulation in aquatic food chains causes otherwise harmless concentrations of selenium to reach toxic levels, and the selenium in contaminated sediments can be cycled into food chains for decades. The lessons learned from Belews Lake provide information useful for protecting aquatic ecosystems as new selenium issues emerge.     

Detection of poisoning by Impila (Callilepis laureola) in a mother and child

Poisoning with impila (Callilepis laureola) is a recurring phenomenon in South Africa. Cases of poisoning with other plants which contain atractyloside also occur in Europe and the Americas. Since poisoning leads to rapid death from renal and/or hepatic failure, it is suspected that many cases are undiagnosed; this is especially so in South Africa, where patients may die without reaching hospital and do not often admit to ingestion of a traditional remedy. We have developed a thin layer chromatographic method for the detection of impila constituents in urine. We describe the clinical symptoms and the application of the screening method to diagnosis in the case of a mother and child, who both showed symptoms of impila poisoning; the mother died but the child survived. This method is rapid and may be used for the definitive diagnosis in cases of poisoning with atractyloside-containing plants.     

Potential Changes in Disease Patterns and Pharmaceutical Use in Response to Climate Change

As climate change alters environmental conditions, the incidence and global patterns of human diseases are changing. These modifications to disease profiles and the effects upon human pharmaceutical usage are discussed. Climate-related environmental changes are associated with a rise in the incidence of chronic diseases already prevalent in the Northern Hemisphere, for example, cardiovascular disease and mental illness, leading to greater use of associated heavily used Western medications. Sufferers of respiratory diseases may exhibit exacerbated symptoms due to altered environmental conditions (e.g., pollen). Respiratory, water-borne, and food-borne toxicants and infections, including those that are vector borne, may become more common in Western countries, central and eastern Asia, and across North America. As new disease threats emerge, substantially higher pharmaceutical use appears inevitable, especially of pharmaceuticals not commonly employed at present (e.g., antiprotozoals). The use of medications for the treatment of general symptoms (e.g., analgesics) will also rise. These developments need to be viewed in the context of other major environmental changes (e.g., industrial chemical pollution, biodiversity loss, reduced water and food security) as well as marked shifts in human demographics, including aging of the population. To identify, prevent, mitigate, and adapt to potential threats, one needs to be aware of the major factors underlying changes in the use of pharmaceuticals and their subsequent release, deliberately or unintentionally, into the environment. This review explores the likely consequences of climate change upon the use of medical pharmaceuticals in the Northern Hemisphere.     

Role of reactive oxygen intermediates in cellular responses to dietary cancer chemopreventive agents

Epidemiological studies continue to support the premise that diets rich in fruits and vegetables may offer protection against cancer of various anatomic sites. This correlation is quite persuasive for vegetables including ALLIUM (e. g., garlic) and cruciferous (e. g., broccoli and watercress) vegetables. The bioactive food components responsible for the cancer chemopreventive effects of various edible plants have been identified. For instance, the anticancer effects of ALLIUM and cruciferous vegetables are attributed to organosulfur compounds (e. g., diallyl trisulfide) and isothiocyanates (e. g., sulforaphane and phenethyl isothiocyanate), respectively. Bioactive food components with anticancer activity are generally considered to be antioxidants due to their ability to modulate expression/activity of antioxidative and phase 2 drug-metabolizing enzymes and scavenging free radicals. At the same time, more recent studies have provided convincing evidence to indicate that certain dietary cancer chemopreventive agents cause generation of reactive oxygen species (ROS) to trigger signal transduction culminating in cell cycle arrest and/or programmed cell death (apoptosis). Interestingly, the ROS generation by some dietary anticancer agents is tumor cell specific and does not occur in normal cells. This review summarizes experimental evidence supporting the involvement of ROS in cellular responses to cancer chemopreventive agents derived from common edible plants.     

Development of standardized methodology for identifying toxins in clinical samples and fish species associated with tetrodotoxin-borne poisoning incidents

Tetrodotoxin (TTX) is a naturally occurring toxin in food, especially in puffer fish. TTX poisoning is observed frequently in South East Asian regions. In TTX-derived food poisoning outbreaks, the amount of TTX recovered from suspicious fish samples or leftovers, and residual levels from biological fluids of victims are typically trace. However, liquid chromatography–mass spectrometry and liquid chromatography–tandem mass spectrometry methods have been demonstrated to qualitatively and quantitatively determine TTX in clinical samples from victims. Identification and validation of the TTX-originating seafood species responsible for a food poisoning incident is needed. A polymerase chain reaction-based method on mitochondrial DNA analysis is useful for identification of fish species. This review aims to collect pertinent information available on TTX-borne food poisoning incidents with a special emphasis on the analytical methods employed for TTX detection in clinical laboratories as well as for the identification of TTX-bearing species.     

Food-derived bioactive peptides--opportunities for designing future foods

Dietary proteins are known to carry a wide range of nutritional, functional and biological properties. Nutritionally, the proteins are a source of energy and amino acids, which are essential for growth and maintenance. Functionally, the proteins contribute to the physicochemical and sensory properties of various protein-rich foods. Furthermore, many dietary proteins possess specific biological properties which make these components potential ingredients of functional or health-promoting foods. Many of these properties are attributed to physiologically active peptides encrypted in protein molecules. Particularly rich sources of such peptides are milk and egg, but they are also found in meat of various kinds as well as many plants. These peptides are inactive within the sequence of parent protein and can be released during gastrointestinal digestion or food processing. Depending on the amino acid sequence, these peptides may exert a number of different activities in vivo, affecting, e.g., the cardiovascular, endocrine, immune and nervous systems in addition to nutrient utilization. There is increasing commercial interest in the production of bioactive peptides from various sources. Industrial-scale production of such peptides is, however, hampered by the lack of suitable technologies. Bioactive peptides can also be produced from milk proteins through fermentation of milk, by starters employed in the manufacture of fermented milks or cheese. In particular, antihypertensive peptides have been identified in fermented milk, whey and ripened cheese. A few of these peptides have been commercialised in the form of fermented milks. There is a need to develop technologies which retain or even enhance the activity of bioactive peptides in food systems. Also, it is essential to study the optimum utilization of such peptides during passage through the gastrointestinal tract.     

Pharmacokinetic considerations in clinical toxicology: clinical applications

Pharmacokinetic and pharmacodynamic principles should be regarded in the assessment and proper management of patients exposed to a poison. Clinicians must apply these principles to make rational clinical decisions regarding the significance of the poisoning (risk assessment) and to formulate an appropriate management plan. However, pharmacokinetic processes and parameters may be changed in the patient with acute poisoning. This may result from saturation of the capacity of a number of physiological processes due to the high dose, or the toxic effects of the poison may change these processes directly. For example, absorption kinetics may be altered because of increased gastrointestinal transit time (e.g. cholinergic receptor antagonists) or saturable absorption (e.g. methotrexate). Saturation of protein binding may increase the volume of distribution and thereby increase the elimination half-life (e.g. salicylates). Alteration of the acid-base balance (poison-induced or iatrogenic) may also increase or decrease the distribution of a poison. Saturation of metabolism at high doses can prolong toxicity (e.g. phenytoin) or lead to other routes of metabolism that lead to increased toxicity (e.g. paracetamol [acetaminophen]). Excretion may be reduced by saturation of active transporters or decreased renal blood flow.A better understanding of pharmacokinetic principles should improve the clinical care of patients. It should lead to more accurate interpretation of blood concentrations or biomarkers (e.g. ECG intervals or acetylcholinesterase activity) and how these relate to the time course for that poison, and better prediction of prognosis. This in turn, indicates the appropriate duration of observation and the requirement for some specific treatments. Many specific poisoning treatments aim to favourably alter the pharmacokinetics of the poison. These include activated charcoal, whole bowel irrigation, extracorporeal elimination, chelating agents, antitoxins and urinary alkalinisation. The evidence supporting them, their indications and limitations can only be understood using pharmacokinetic principles. These principles also underpin the appropriate choice within the flexible dosage regimen for many antidotes. In particular, naloxone, flumazenil, methylene blue, atropine and pralidoxime all use variable doses and have an elimination half-life that is much shorter than many (but not all) of the poisons treated by these agents. A firm grounding in pharmacokinetics/toxicokinetics should be regarded as a core competency for all professionals involved in clinical care or undertaking research in clinical toxicology.     

A system approach to pharmacodynamics. I: Theoretical framework

A general theoretical framework is constructed for the relationship between a pharmacokinetic response r (e.g., systemic drug concentration or input rate), and an observed pharmacologic effect response E. The overall relationship may be described mathematically by E = omega(r) = omega p(omega b(omega r(r))) where omega is an operator that describes the overall relationship, and omega r, omega b, and omega p are operators that describe the contributions of components of the pharmacodynamic system. The kinetic basis for applying certain general mathematical properties such as linearity are discussed. The result is the introduction of various specific mathematical structures that may be applied to pharmacodynamic systems [e.g., E = phi t(r), E = phi t(psi r*r), E = phi p(psi p*phi b(r)), and E = phi p(psi p*phi b(psi r*r))].