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Introduction to Cancer
Published in David E. Thurston, Ilona Pysz, Chemistry and Pharmacology of Anticancer Drugs, 2021
The radio frequency electromagnetic fields emitted by mobile phones are absorbed by the body and particularly by the head when the handset is held close to the ear. However, studies into the possible health consequences of frequent handset use has proved inconclusive because the technology has only been widely used within the last two decades, whereas it can take many decades for cancer to develop. In 2010, an IARC study known as “Interphone” suggested that making phone calls for more than half an hour a day over 10 years could increase the risk of developing gliomas in the brain or spine by 40%. In early 2011, 31 scientists from 14 countries reviewed the Interphone data and other studies, including a Swedish study that showed an increased brain tumor risk among mobile users. It was concluded that there was “limited” evidence that mobile phones are linked to brain cancer, suggesting that it could be down to chance rather than causation. They decided that although there was inadequate proof that mobile phones cause cancer, evidence is still accumulating and, in the meantime, some element of risk should be assumed with a need to monitor any links between mobile phones and cancer risk. It is noteworthy that the classification of mobile phones as “possibly carcinogenic” is the third highest rating the IARC has used in listing more than 900 agents. This rating is just below “carcinogenic to humans” (e.g., cigarettes) and “probably carcinogenic” (e.g., diesel exhausts and creosote).
Exposure Assessment
Published in Ted W. Simon, Environmental Risk Assessment, 2019
There remains considerable uncertainty regarding the extent of the dermal exposure component for creosote workers. A urinary biomarker of exposure to PAHs is hydroxypyrene.220 Several studies could not account for the amount of hydroxypyrene in urine from inhalation exposure alone in creosote workers, and claimed this was due to dermal exposure with no additional evidence.221,222
‘It’s all a cruel hoax’
Published in Solomon Posen, Edward J Huth, The Doctor in Literature, 2018
Dr Roussel, apparently ‘brisk, sympathetic ... courteous and optimistic’ promises [Paul] that he will be cured by the beginning of the summer and fit to get married.62 Roussel’s Pollyanna attitude evaporates when his ‘creosote’ treatment produces a number of complications. When he discovers that Paul can no longer pay for his stay in hospital, he declares ‘the treatment has served its purpose; it is time for it to be stopped’.62 Even the kind and generous Dr Dubois displays an initial ‘coldness’,61 due to a letter from one of Paul’s previous medical attendants. The contents of this letter are not disclosed but it presumably describes Paul as a ‘difficult’ patient. Professor Klauss, the famous Swiss specialist, ‘an enormous man, bald, bearded and frock-coated’, constitutes Paul Davenant’s last court of appeal.63 Klauss, courteous and analytical with only one lapse into sarcasm (see p. 83) and one glance at his watch (see also p. 60), summarizes the various treatment options. The realistic choices, neither of them satisfactory, lie between doing nothing and, after two and a half years of complications resulting from the first pneumothorax, inducing a second pneumothorax.63
Drug discovery for primary amebic meningoencephalitis: from screen to identification of leads
Published in Expert Review of Anti-infective Therapy, 2021
Despite the role of natural products in the development of drugs for over a century, research on identifying new natural product-based anti-N. fowleri agents is limited. Both plants and microbial secondary metabolites are sources of novel compounds that display antiparasitic activity [47–49]. Isoflavans, 3S(+)-7-methoxymanuifolin K and manuifolin K, were isolated from methanolic extracts of Dalea aurea (Fabaceae) and tested against N. fowleri trophozoites. At a concentration of 30 µM, the compounds exhibited growth inhibition of trophozoites comparable to that of amphotericin B [50]. Lignans isolated from creosote bush Larrea tridentata showed moderate amebicidal activity against N. fowleri [51]. Another plant secondary metabolite, cinnamic acid (trans-3-phenylacrylic acid), was tested for anti-N. fowleri activity. Cinnamic acid alone and gold nanoparticles conjugated with cinnamic acid demonstrated significant growth inhibition of trophozoites at 2.5 µM [52]. Curcumin, a polyphenol isolated from Curcuma longa, has a longstanding use as an antimicrobial and anti-inflammatory agent [53]. When tested against N. fowleri, curcumin and gold nanoparticle-conjugated compound showed amebicidal activity [54] (Table 1). Secondary metabolites representing a class of natural products pharmacophore can be further optimized to develop more potent antiamebic compounds.
Levels of polyaromatic hydrocarbons (PAHs) in sediment samples from selected Jordanian dams
Published in Toxin Reviews, 2021
Sharif Arar, Mahmoud Alawi, Ali Alnawaiseh, Mohanad Masad
The anthropogenic sources include products of incomplete combustion of organic material in the coal, petroleum and metal smelting industries (Keith 1977, Bradley et al. 1994). They also include urban runoffs and deterioration of asphalt pavement surfaces and car tires. PAHs are ubiquitous and there exist several hundreds of them in the environment (Wild and Jones 1995, Ramesh et al. 2004). They are usually found as a mixture containing two or more of these compounds and commercially available pure PAHs are usually colorless, white or pale yellow-green solids which are odorless or have a faintly pleasant odor (Buha 2011). Some PAHs are used in medicines, dyes, plastics, and pesticides. Others are contained in asphalt used in road construction as well as found in substances such as crude oil, coal, coal tar pitch, creosote, and roofing tar (ATSDR 1995).
Bioactivation of herbal constituents: mechanisms and toxicological relevance
Published in Drug Metabolism Reviews, 2019
Nordihydroguaiaretic Acid (NDGA), a major lignan isolated from the leaves of the evergreen desert shrub Larrea tridentata (Creosote bush) in the southwest United States, has been used in folk medicine for treatment of multiple diseases including cardiovascular diseases, neurological disorders and cancers (Lü et al. 2010). NDGA has a wide range of pharmacological activities including radical-scavenging, antioxidant, cytoprotective, and antitumoral activities (Hernández-Damián et al. 2014). As a lipophilic antioxidant, NDGA was used as a preservative in food industry and was later withdrawn due to its nephrotoxicity and hepatotoxicity in animals (Grice et al. 1968; Lambert et al. 2002). NDGA is the active ingredient in the herbal medicine Chaparral prepared from the creosote bush, and chronic use has been associated with hepatotoxicity in humans (Sheikh et al. 1997). It has been shown that NDGA, a di-catechol lignan, was oxidized to ortho-quinones to form mono- and di-GSH-NDGA adducts (Jeong et al. 2017) (Figure 11(e)). A toxicological mechanism involving ortho-quinone formation has been suggested to elicit liver and kidney toxicities of NGDA (Billinsky et al. 2007). On the other hand, autoxidation of NGDA to ortho-quinones likely contributed to its pharmacological properties including lipoxygenase inhibition and modulation of Keap1/Nrf2/ARE redox signaling system (Hernández-Damián et al. 2014).