Plasma levels of nicotine and safety of smokers wearing transdermal delivery systems during multiple simultaneous intake of nicotine and during exercise

Green Tobacco Sickness: A Brief Review

Green tobacco sickness (GTS) is the condition that mainly affects the tobacco harvesters. The condition is prevalent in Asian and South American tobacco harvesters. The present review was conducted to discuss the etiology, epidemiology, symptoms, and prevention of GTS. It is caused by the absorption of nicotine through the skin while the workers are engaged in handling the uncured tobacco leaves. The symptoms include nausea, vomiting, pallor, dizziness, headaches, increased perspiration, chills, abdominal pain, diarrhea, increased salivation, prostration, weakness, breathlessness, and occasional lowering of blood pressure. The prevalence of GTS varies from 8.2 to 47% globally. The use of personal protective equipment like water-resistant clothing, chemical-resistant gloves, plastic aprons, and rain-suits with boots should be used by the tobacco farmers to prevent its occurrence. An international-level awareness campaign has to be taken up and more stringent workers safety regulations have to be formulated.

Differential modulation of nicotine-induced gemcitabine resistance by GABA receptor agonists in pancreatic cancer cell xenografts and in vitro

Background

Pancreatic cancer is frequently resistant to cancer therapeutics. Smoking and alcoholism are risk factors and pancreatic cancer patients often undergo nicotine replacement therapy (NRT) and treatment for alcohol dependence. Based on our report that low dose nicotine within the range of NRT causes gemcitabine resistance in pancreatic cancer, our current study has tested the hypothesis that GABA or the selective GABA-B-R agonist baclofen used to treat alcohol dependence reverse nicotine-induced gemcitabine resistance in pancreatic cancer.

Methods

Using mouse xenografts from the gemcitabine--sensitive pancreatic cancer cell line BXPC-3, we tested the effects of GABA and baclofen on nicotine-induced gemcitabine resistance. The levels of cAMP, p-SRC, p-ERK, p-AKT, p-CREB and cleaved caspase-3 in xenograft tissues were determined by ELISA assays. Expression of the two GABA-B receptors, metalloproteinase-2 and 9 and EGR-1 in xenograft tissues was monitored by Western blotting. Mechanistic studies were conducted in vitro, using cell lines BXPC-3 and PANC-1 and included analyses of cAMP production by ELISA assay and Western blots to determine protein expression of GABA-B receptors, metalloproteinase-2 and 9 and EGR-1.

Results

Our data show that GABA was as effective as gemcitabine and significantly reversed gemcitabine resistance induced by low dose nicotine in xenografts whereas baclofen did not. These effects of GABA were accompanied by decreases in cAMP, p-CREB, p-AKT, p-Src, p-ERK metalloproteinases-9 and -2 and EGR-1 and increases in cleaved caspase-3 in xenografts whereas baclofen had the opposite effects. In vitro exposure of cells to single doses or seven days of nicotine induced the protein expression of MMP-2, MMP-9 and EGR-1 and these responses were blocked by GABA. Baclofen downregulated the protein expression of GABA-B-Rs in xenograft tissues and in cells exposed to baclofen for seven days in vitro. This response was accompanied by inversed baclofen effects from inhibition of cAMP formation after single dose exposures to stimulation of cAMP formation in cells pretreated for seven days.

Conclusions

These findings suggest GABA as a promising single agent for the therapy of pancreatic cancer and to overcome nicotine-induced gemcitabine resistance whereas treatment with baclofen may increase gemcitabine resistance.

Developmental toxicity assay using high content screening of zebrafish embryos

Typically, time-consuming standard toxicological assays using the zebrafish (Danio rerio) embryo model evaluate mortality and teratogenicity after exposure during the first 2 days post-fertilization. Here we describe an automated image-based high content screening (HCS) assay to identify the teratogenic/embryotoxic potential of compounds in zebrafish embryos in vivo. Automated image acquisition was performed using a high content microscope system. Further automated analysis of embryo length, as a statistically quantifiable endpoint of toxicity, was performed on images post-acquisition. The biological effects of ethanol, nicotine, ketamine, caffeine, dimethyl sulfoxide and temperature on zebrafish embryos were assessed. This automated developmental toxicity assay, based on a growth-retardation endpoint should be suitable for evaluating the effects of potential teratogens and developmental toxicants in a high throughput manner. This approach can significantly expedite the screening of potential teratogens and developmental toxicants, thereby improving the current risk assessment process by decreasing analysis time and required resources.

Symptoms of nicotine toxicity in subjects achieving high cotinine levels during nicotine replacement therapy

INTRODUCTION

Nicotine replacement therapy (NRT) aids smoking reduction and cessation. Although NRT is effective and safe, some smokers may achieve high nicotine levels. The purpose of this study was to determine the incidence and severity of nicotine-related adverse events in subjects with levels of cotinine, a metabolite of nicotine, that increased by >50% compared with baseline smoking in controlled clinical trials of NRT.

METHODS

Data from participants in randomized, double-blind, controlled trials of various formulations of NRT (Nicorette®), including patch, gum, oral inhaler, sublingual tablet, nasal spray, mouth spray, and combinations, were extracted from a clinical database. Eligible studies were performed between 1989 and 2010. In addition to baseline, at least 1 subsequent plasma or salivary cotinine concentration was measured, and adverse events were recorded simultaneously. Of 28 eligible studies, 24 were smoking cessation studies and 4 were smoking reduction studies.

RESULTS

Cotinine levels that increased by >50% above baseline were recorded during treatment in 746 of 7,120 subjects (10.5%). Nausea was reported in 16 subjects (0.2% of the total, upper 99% confidence limit [CL] 0.4%), vomiting in 2 subjects (0.0%, upper 99% CL 0.1%), palpitations in 5 subjects (0.1%, upper 99% CL 0.2%), dizziness in 11 subjects (0.2%; upper 99% CL 0.3%), and headache in 35 subjects (0.5%, upper 99% CL 0.7%).

CONCLUSIONS

Typical symptoms indicating nicotine overdose together with high cotinine levels were rare during treatment with NRT. These findings support the safety of NRT for smoking cessation or reduction.

Chronic nicotine inhibits the therapeutic effects of gemcitabine on pancreatic cancer in vitro and in mouse xenografts

AIM OF STUDY

Smoking is an established risk factor for pancreatic cancer and nicotine replacement therapy (NRT) often accompanies chemotherapy. The current study has tested the hypothesis that chronic exposure to low dose nicotine reduces the responsiveness of pancreatic cancer to the leading therapeutic for this cancer, gemcitabine.

METHODS

The effects of chronic nicotine (1 μm/L) on two pancreatic cancer cell lines in vitro and in a xenograft model were assessed by immunoassays, Western blots and cell proliferation assays.

RESULTS

Exposure in vitro to nicotine for 7 days inhibited the gemcitabine-induced reduction in viable cells, gemcitabine-induced apoptosis as indicated by reduced expression of cleaved caspase-3 while inducing the phosphorylation of signalling proteins extracellular signal-regulated kinase (ERK), v-akt thymoma viral oncogene homolog (protein kinase B, AKT) and Src. Nicotine (1 μm/L) in the drinking water for 4 weeks significantly reduced the therapeutic response of mouse xenografts to gemcitabine while reducing the induction of cleaved caspase-3 and the inhibition of phosphorylated forms of multiple signalling proteins by gemcitabine in xenograft tissues.

CONCLUSIONS

Our experimental data suggest that continued moderate smoking and NRT may negatively impact therapeutic outcomes of gemcitabine on pancreatic cancer and that clinical studies in cancer patients are now warranted.

FOXM1 upregulation is an early event in human squamous cell carcinoma and it is enhanced by nicotine during malignant transformation

BACKGROUND

Cancer associated with smoking and drinking remains a serious health problem worldwide. The survival of patients is very poor due to the lack of effective early biomarkers. FOXM1 overexpression is linked to the majority of human cancers but its mechanism remains unclear in head and neck squamous cell carcinoma (HNSCC).

METHODOLOGY/PRINCIPAL FINDINGS

FOXM1 mRNA and protein expressions were investigated in four independent cohorts (total 75 patients) consisting of normal, premalignant and HNSCC tissues and cells using quantitative PCR (qPCR), expression microarray, immunohistochemistry and immunocytochemistry. Effect of putative oral carcinogens on FOXM1 transcriptional activity was dose-dependently assayed and confirmed using a FOXM1-specific luciferase reporter system, qPCR, immunoblotting and short-hairpin RNA interference. Genome-wide single nucleotide polymorphism (SNP) array was used to 'trace' the genomic instability signature pattern in 8 clonal lines of FOXM1-induced malignant human oral keratinocytes. Furthermore, acute FOXM1 upregulation in primary oral keratinocytes directly induced genomic instability. We have shown for the first time that overexpression of FOXM1 precedes HNSCC malignancy. Screening putative carcinogens in human oral keratinocytes surprisingly showed that nicotine, which is not perceived to be a human carcinogen, directly induced FOXM1 mRNA, protein stabilisation and transcriptional activity at concentrations relevant to tobacco chewers. Importantly, nicotine also augmented FOXM1-induced transformation of human oral keratinocytes. A centrosomal protein CEP55 and a DNA helicase/putative stem cell marker HELLS, both located within a consensus loci (10q23), were found to be novel targets of FOXM1 and their expression correlated tightly with HNSCC progression.

CONCLUSIONS/SIGNIFICANCE

This study cautions the potential co-carcinogenic effect of nicotine in tobacco replacement therapies. We hypothesise that aberrant upregulation of FOXM1 may be inducing genomic instability through a program of malignant transformation involving the activation of CEP55 and HELLS which may facilitate aberrant mitosis and epigenetic modifications. Our finding that FOXM1 is upregulated early during oral cancer progression renders FOXM1 an attractive diagnostic biomarker for early cancer detection and its candidate mechanistic targets, CEP55 and HELLS, as indicators of malignant conversion and progression.

Adverse drug reactions in patients with cardiovascular disease

Adverse drug reactions (ADRs) occur frequently in modern medical practice, increasing morbidity and mortality and inflating the cost of care. Patients with cardiovascular disease are particularly vulnerable to ADRs due to their advanced age, polypharmacy, and the influence of heart disease on drug metabolism. The ADR potential for a particular cardiovascular drug varies with the individual, the disease being treated, and the extent of exposure to other drugs. Knowledge of this complex interplay between patient, drug, and disease is a critical component of safe and effective cardiovascular disease management. The majority of significant ADRs involving cardiovascular drugs are predictable and therefore preventable. Better patient education, avoidance of polypharmacy, and clear communication between physicians, pharmacists, and patients, particularly during the transition between the inpatient to outpatient settings, can substantially reduce ADR risk.

Smoking cessation: significance and implications for children

A number of people in the USA who are still current smokers remain a staggering figure. Although this number continues to decrease, there is still a considerable amount of second-hand smoke. More importantly and for the purpose of this review, the detrimental effects of passive smoke in children is significant. We will not review the specific health effects of passive smoke, but for pediatricians, in particular, it is important to place in perspective programs that are available to influence the parents of children to stop smoking. Indeed, approximately 25% of all children aged 3-11 live in a household with at least one smoker. Despite the increasing number of communities in the states that have instituted restrictions or complete bans on smoking in the workplace and in many public areas, the principal site of smoking remains the home.

Effect of application sites and multiple doses on nicotine pharmacokinetics in healthy male Japanese smokers following application of the transdermal nicotine patch

The transdermal nicotine patch, which contains 25 mg nicotine per 30 cm(2), is designed to deliver approximately 15 mg nicotine to the blood circulation in 16 hours of application for the treatment of smoking cessation. It was applied to 3 different skin sites (upper arm, abdomen, and back) to examine regional variations in percutaneous nicotine absorption in a single-dose, 3-period, crossover study involving 9 healthy male Japanese smokers. Nicotine pharmacokinetics during once-daily application of the transdermal nicotine patch for 5 days was also investigated in 10 healthy smokers. There were statistically significant effects of application sites on percutaneous nicotine absorption. The ratios (90% confidence intervals) of AUC and C(max) for comparison to the upper arm were 102% (88, 117%) and 106% (95, 119%) for the back and 75% (65, 87%) and 75% (66, 84%) for the abdomen, respectively. These suggest that systemic exposure after application to the upper arm was greater compared with the abdomen but equivalent to the back. Following multiple doses, linear pharmacokinetics and no significant accumulation of nicotine concentrations were observed, and steady state was reached by day 2. Only mild itching and erythema were observed at the application sites. The transdermal nicotine patch was well tolerated in both studies.

Green tobacco sickness in children and adolescents

Tobacco (Nicotiana tabacum) is cultivated in more than 100 countries, and in 2004, some 5.73 million metric tons dry weight of tobacco were grown worldwide. The top five tobacco producers forecast for 2004 are China (2.01 million metric tons; 35.1%), Brazil (757 thousand metric tons; 13.2%), India (598 thousand metric tons; 10.4%), United States (358 thousand metric tons; 6.2%), and Malawi (138 thousand metric tons; 2.4%). Together, these five countries account for two-thirds of worldwide tobacco production. Tobacco farming presents several hazards to those who cultivate and harvest the plant. Although some of these hazards, such as pesticide exposure and musculoskeletal trauma, are faced by workers in other types of agricultural production, tobacco production presents some unique hazards, most notably acute nicotine poisoning, a condition also known as green tobacco sickness (GTS). GTS is an occupational poisoning that can affect workers who cultivate and harvest tobacco. It occurs when workers absorb nicotine through the skin as they come into contact with leaves of the mature tobacco plant. GTS is characterized largely by nausea, vomiting, headache, muscle weakness, and dizziness. Historically, children have played a role in agricultural production in the United States, and they continue to do so today. This includes tobacco farming. The North American Guidelines for Children's Agricultural Tasks, a set of injury prevention guidelines prepared by the National Children's Center for Rural and Agricultural Health and Safety, lists GTS as one of several hazards children face when working on tobacco farms. Children 17 years of age and younger who work on U.S. tobacco farms come from three main groups: members of farm families, migrant youth laborers (primarily Latinos), and other hired local children. All three groups are at risk for GTS. Beyond the U.S., tobacco production using child labor is an emerging topic of concern in developing nations. An international movement, advocated by the Eliminating Child Labor in Tobacco Foundation, is underway to restrict child labor in tobacco production. GTS is a unique occupational poisoning associated with tobacco farming. We suspect that many public health practitioners, clinicians, advocates, and researchers are unaware of GTS among children and adolescents. In this article, we provide an overview of GTS among young people who work in tobacco, summarize reports documenting pediatric GTS cases, explain GTS etiology, and present three case studies of pediatric GTS in Kentucky. In addition, we discuss the need for expanded surveillance and prevention of GTS, both in the United States and globally.

Effectiveness of payment for reduced carbon monoxide levels and noncontingent payments on smoking behaviors in cocaine-abusing outpatients wearing nicotine or placebo patches

In a 2-week intervention to reduce cigarette smoking among outpatients in treatment for cocaine addiction, 20 subjects were randomly assigned to a contingent group, receiving monetary vouchers for breath samples with carbon monoxide (CO) levels of 8 ppm or less, or to a noncontingent group, receiving vouchers regardless of CO level. Subjects wore either nicotine or placebo patches in a randomized crossover design. Contingent subjects had significantly lower CO levels and met the 8 ppm target significantly more often than did noncontingent subjects; however, number of cigarettes reported smoked did not differ between groups. Use of nicotine patches resulted in CO levels significantly lower than did use of placebo patches, but levels still exceeded 8 ppm regardless of type of patch. Because contingent reward helped cocaine-dependent smokers achieve nonsmoking CO targets, behavioral antismoking interventions merit continued study in similar populations.