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At least 343 records · Page 19Linked to original sources
PubMed2003

Evaluation of relationships between mainstream smoke acetaldehyde and "tar" and carbon monoxide yields in tobacco smoke and reducing sugars in tobacco blends of U.S. commercial cigarettes.

Mainstream (MS) smoke acetaldehyde (AA), carbon monoxide (CO), and "tar" yields and percentage total reducing sugars in the tobacco blends from a Philip Morris USA database of a large number of commercial U.S. cigarettes were analyzed. MS smoke acetaldehyde is significantly correlated with "tar" yield and also with MS smoke carbon monoxide. These correlations are consistent with recently available data, including the 1999 Massachusetts Benchmark Study. MS smoke acetaldehyde yield is not correlated with reducing sugar (RS) concentration in the tobacco blend. For the available data over the time period 1985-1993, the concentration of reducing sugars (mean values for the brands tested) decreased. The correlations found between MS smoke acetaldehyde yield and "tar" and MS smoke carbon monoxide, and the percentage of the variance in AA yield explained by "tar" and MS smoke CO, coupled with the lack of correlation between "tar" normalized MS smoke AA and RS, plus related pyrolysis studies, support the hypothesis that MS smoke acetaldehyde yields are affected more by cigarette design characteristics influencing total smoke production than by tobacco reducing sugars.

Acetaldehyde↗
PubMed2006

A randomized, investigator-masked clinical evaluation of the efficacy and safety of clobetasol propionate 0.05% shampoo and tar blend 1% shampoo in the treatment of moderate to severe scalp psoriasis.

The clinical benefit of currently available tar blend shampoos for the treatment of scalp psoriasis is restricted due to their limited efficacy, low cosmetic appeal and potential for carcinogenicity. This 4-week multicentre, randomized, parallel-group, investigator-masked study included 162 subjects and aimed to compare the efficacy, safety and cosmetic acceptability of clobetasol propionate 0.05% shampoo versus a currently marketed tar blend 1% shampoo in subjects with moderate to severe scalp psoriasis. Clobetasol propionate shampoo was superior to tar blend shampoo with respect to all efficacy variables tested (p<0.001): Total and Global Severity Score; erythema; plaque thickening; desquamation; pruritus; total scalp area involved; and the subject's global assessment of clinical improvement. Both treatments were safe and well-tolerated. Furthermore, more subjects indicated that clobetasol propionate shampoo was more cosmetically acceptable than tar blend shampoo. Clobetasol propionate 0.05% shampoo is a good alternative to tar blend shampoo in the treatment of moderate to severe scalp psoriasis.

Administration, Cutaneous↗
PubMed2002

Effects of cigarette smoking with different tar content on erythrocyte oxidant/antioxidant status.

In this study, the effects of cigarettes with differing tar content on erythrocyte oxidant/antioxidant status was investigated. Malondialdehyde (MDA) as an indicator of oxidant status and superoxide radical scavenger activity (SSA) as an indicator of antioxidant status were measured in erythrocytes from 20 smokers and 10 non-smoker controls. Ten of the 20 smoking subjects smoked five cigarettes with full flavour low tar (FFLT with 12 mg tar) and the others smoked five cigarettes with full flavour high tar (FF with 23 mg tar) over 1 hour. Initial blood samples from both groups at fasting, followed by further samples from smokers at 1.5 hours and 3 hours after smoking. Initial erythrocyte MDA level and SSA activity were found to be higher in the smoking groups compared to non-smokers. Furthermore, both parameters were significantly higher at the 1.5-hour and 3-hour erythrocyte samples when compared to initial values in the FFLT group. However, there were no statistically significant differences between SSA values established at different times in FF group. Results suggest that smoking causes oxidant load in the erythrocytes. Although a compensatory mechanism (i.e. increased SSA activities) develops in the FFLT group after smoking, this cannot prevent peroxidation reactions (i.e. increased MDA levels) in the erythrocytes. As to the types of cigarettes, both seem to have oxidant potential, but oxidation degree in the FFLT group is higher than that of FF group. These results suggest that antioxidant supplementation to smokers might be beneficial to decrease cellular oxidation damages.

Adult↗
PubMed2003

Determination of tar, nicotine, and carbon monoxide yields in the smoke of bidi cigarettes.

A survey of the nicotine, tar, and carbon monoxide (CO) levels in mainstream smoke from 21 brands of bidi cigarettes and five brands of traditional cigarettes was conducted using a variation of the Federal Trade Commission (FTC) standardized cigarette smoking machine method. The primary difference between this method and the FTC method was a reduction of the 60-s puff interval to 15 s. The shorter puff interval was required to prevent the bidi cigarettes from self-extinguishing and may represent a closer approximation to human usage. The goal of this study was to evaluate the smoke-delivery potential for tar, nicotine, and CO in mainstream smoke from bidi cigarettes compared with traditional domestic cigarettes smoked under identical conditions. Approximately half of the bidi brands examined were marketed as filtered varieties. Unlike traditional cigarettes, the filtered and unfiltered bidi brands yielded comparable smoke deliveries. Thus, a filtered bidi cigarette brand does not provide any harm-reduction benefit that might result from a reduction in levels of tar, nicotine, and CO compared with an unfiltered variety. Our findings indicate that bidi cigarettes can deliver high levels of tar (77.9+/-9.5 mg/bidi), nicotine (2.7+/-.4 mg/bidi), and CO (39.2+/-5.7 mg/bidi). In comparison, traditional cigarettes smoked using the bidi cigarette protocol have lower tar and CO yields, but have nicotine deliveries comparable with bidi cigarettes.

Carbon Monoxide↗
PubMed2004

The "low-tar" strategy and the changing construction of Australian cigarettes.

This article documents design changes in Australian cigarettes since the adoption of a "low-tar" harm reduction strategy in 1966. It also determines the relative contributions of specific technologies to machine-tested tar and nicotine yields in 1980 and 1994, using data from tobacco industry documents. Our findings are consistent with a first generation of low-tar cigarettes, which relied primarily on filtration efficiency, being displaced by a second generation, which relied heavily on filter ventilation and were more attractive to consumers. In 1980, both tar and nicotine yields correlated most strongly with filter density (r=-.66, p<.01, and r=-.70, p<.01), whereas in 1994 both tar and nicotine yields correlated most strongly with percentage filter ventilation (r=-.97, p<.01, and r=-.95, p<.01). We also found that median percentage alkaloid content of tobacco rods rose from 2.16% in 1980 to 2.4% in 1994, despite median nicotine yield declining from 1.0 mg to.58 mg. These changes can be expected to reduce the utility of the FTC/ISO yield testing system.

Australia↗
PubMed1989

Chromosomal alterations in peripheral blood lymphocytes, urinary mutagenicity and excretion of polycyclic aromatic hydrocarbons in six psoriatic patients undergoing coal tar therapy.

Six male non-smoking subjects treated for psoriasis with topical applications of pure coal tar or 4% coal tar-containing ointment were examined in order to assess the genotoxic risk associated with this type of therapy. Mutagenicity in urine samples collected before and during the coal tar therapy was evaluated in the plate incorporation assay on Salmonella typhimurium strain TA98 in the presence of S9 mix and beta-glucuronidase. Total urinary polycyclic aromatic hydrocarbon (PAH) levels were evaluated in parallel by high resolution gas chromatography/mass spectrometry. In addition, sister chromatid exchanges and chromosomal aberrations were also analysed in peripheral blood lymphocytes collected before, during and after the end of the coal tar applications. The results suggest that urinary mutagenicity levels as well as the frequencies of chromosome aberrations and sister chromatid exchanges in lymphocytes are related to the levels of exposure to coal tar. Moreover the kinetics of repair of chromosome damage in relation to different exposure levels and the capacity of the urinary mutagenicity assay to correctly identify the exposure to significant levels of PAH are discussed.

Administration, Topical↗
PubMed1987

DNA synthesis is blocked by cigarette tar-induced DNA single-strand breaks.

DNA single-strand breaks are caused by aqueous extracts of cigarette tar, due to the reduction of oxygen to superoxide by tar and the subsequent production of hydroxyl radicals. The action of DNA metabolism enzymes on these single-strand breaks has been studied to probe the consequences of these lesions for DNA repair. Our results demonstrate that cigarette tar-induced nicks are blocked at the 3' terminus since they are totally incapable of activating DNA for DNA synthesis by Escherichia coli DNA polymerase I. The 3' termini of these tar-induced nicks are activated, however, for DNA synthesis by E. coli exonuclease III or by the 3' phosphatase activity of T4 polynucleotide kinase. Because of the inability of tar-induced lesions to support DNA synthesis, they probably require a multi-step process for repair in vivo. As a consequence, the overall likelihood of mutation is increased due to the possibility for error at each step of the repair process.

Bacteriophages↗
PubMed1988

Covalent binding of components of coal-tar, creosote and bitumen to the DNA of the skin and lungs of mice following topical application.

In order to assess the DNA damaging ability of complex carcinogenic mixtures, male Parkes mice were treated topically with solutions of (i) pharmaceutical coal-tar, (ii) creosote, a blend of coal-tar fractions or (iii) bitumen, a product of oil-refining. DNA was isolated from the treated skin and analysed by 32P-post-labelling. A band of radioactivity was obtained on polyethyleneimine--cellulose TLC indicating the formation of DNA adducts by a large number of different chemical compounds present in these fossil fuel products. The chromatographic properties of the adducts were broadly characteristic of those formed by polycyclic aromatic hydrocarbons. The levels of DNA binding were approximately 0.4 fmol total adducts/micrograms DNA 24 h after treatment for coal-tar and creosote and 0.09 fmol/micrograms DNA for bitumen treatment. The persistence of adducts in mouse skin following a single dose of either coal-tar or creosote was found to exhibit a phase of rapid removal, in which one half to two thirds of the initial levels of adducts, detected at 24 h after treatment, were removed by 7 days followed by a second phase in which one half to two thirds of the remainder was removed in the succeeding 25 days. When mice were treated topically with multiple carcinogenic doses of coal-tar, creosote or bitumen for up to 5 weeks, a steady accumulation of adducts was seen in skin DNA during the course of the treatment, approaching a steady-state level towards the end of the treatment period in some instances. A similar accumulation of adducts was also evident in lung DNA, the levels being approximately half those attained in skin. The results demonstrate the application of 32P-post-labelling to the detection of DNA adducts formed in vivo by complex carcinogenic mixtures of the type to which humans are exposed.

Administration, Topical↗
PubMed2026

Non-Coding c.*6C>T Variant in RBM8A Associated With Thrombocytopenia-Absent Radius (TAR) Syndrome in Three Indian Patients.

Thrombocytopenia-absent radius (TAR) syndrome is a rare genetic disorder characterized by the absence of radius in the forearms and a decrease in platelet count. The molecular basis of TAR syndrome is linked to a heterozygous minimal deletion within the 1q21.1 region spanning 200&#x2009;k bases (kb), resulting in a null allele and a nucleotide variation in RBM8A resulting in a hypomorphic allele. Previous studies have identified pathogenic variants in the coding regions of the RBM8A gene as the cause of TAR syndrome. However, the involvement of non-coding variants in disease pathogenesis remains largely unexplored. We investigated the association of a non-coding 3' UTR variant, c.*6C>T, in RBM8A with TAR syndrome in three individuals from two unrelated families of Indian origin. Our study provides evidence that this variant is associated with decreased stability of the transcript and is a hypomorphic allele with disease-causing impact when in trans with a null allele (1q21.1 deletion). The present work is the first application of an mRNA stability assay to directly detect RNA degradation in patients with non-coding RBM8A variants causing TAR syndrome.

Humans↗
PubMed1976

Low-tar medium-nicotine cigarettes: a new approach to safer smoking.

The logic of expecting people who cannot stop smoking to switch to cigarettes that have hardly any nicotine is questionable. Tar and nicotine yields of cigarettes available in Britain today correlate 0-93, and further reduction of tar intake is limited by the reluctance of smokers to tolerate similar reductions in nicotine. A new approach would be to aim at lowering tar yields of cigarettes from the present average of 18 mg to around 6 mg but maintaining nicotine yields at around 1-0 to 1-2 mg, which would be acceptable to most smokers. This approach requires that emphasis be placed on tar: nicotine ratios as well as on the absolute yields. These ratios for brands on sale in Britain today average 14-2 and range from 9-6 to 20-8. They provide an additional guide for comparing the relative harmfulness of different brands. For example, 35% of cigarette smokers in Britain smoke either Embassy Filter or Players No 6 Filter; by changing to John Player Carlton King Size they could reduce their tar intake by more than 20% without having to suffer any nicotine deprivation.

Humans↗
PubMed1993

Tar yield of cigarettes and risk of acute myocardial infarction. GISSI-EFRIM Investigators.

OBJECTIVE: To analyse the relation between tar and nicotine yield of cigarettes smoked in the recent past and the risk of myocardial infarction. DESIGN: Multicentre case-control study conducted between September 1988 and June 1989. SETTING: Over 80 coronary care units in various Italian regions. SUBJECTS: 916 patients with acute myocardial infarction without history of ischaemic heart disease and 1106 controls admitted to hospital for acute conditions not related to known or suspected risk factors for ischaemic heart disease. MAIN OUTCOME MEASURES: Relative risk of myocardial infarction according to type of cigarette smoked adjusted for identified potential confounding factors. Brands of cigarettes classified according to yield of tar and nicotine. RESULTS: Patients with acute myocardial infarction were more often smokers and among smokers they tended to smoke more cigarettes. Compared with non-smokers their estimated relative risks were 3.8, 4.3, 3.2, and 3.7 in the four categories of tar yield (< 10, 10-15, > 15-20, and > 20 mg, respectively). No trend in risk across yields was evident when analysis was restricted to smokers and allowance was made for number of cigarettes. Compared with risks in subjects in the lowest category of tar yield the relative risks were 1.2, 0.8, and 1.0 for the subsequent yields. Compared with risks in non-smokers the relative risks ranged from 9.3 to 12.6 below the age of 50 but no trend was observed with increasing yield. CONCLUSIONS: Changing to cigarettes with a lower tar yield is not an effective means of reducing tobacco related morbidity from myocardial infarction.

Adult↗
PubMed1983

Tar, nicotine, and carbon monoxide yields of some Nigerian cigarettes.

Fourteen cigarette brands manufactured in Nigeria in 1981 were analysed to determine the tar, nicotine, and carbon monoxide yields. Five of the brands belonged to the high and middle to high tar category (greater than 22 mg/cigarette) and nine to the middle tar (17-22 mg/cigarette) category. None of the cigarettes was in the low to middle and low tar (less than 17 mg/cigarette) category. The nicotine and carbon monoxide yields were similar to those of European cigarettes. Tobacco companies need to manufacture low tar cigarettes in the Third World as is the practice in the economically developed parts of the world.

Carbon Monoxide↗
PubMed1996

Compensating lung cancer patients occupationally exposed to coal tar pitch volatiles.

OBJECTIVES: To investigate the process of deciding on compensation claims by lung cancer patients exposed occupationally to coal tar pitch volatiles. METHODS: For each case of lung cancer the probability that it was caused (probability of causation (PC)) by coal tar pitch volatiles was expressed as an increasing function of cumulative exposure to benzo-a-pyrene-years. This was assessed from several exposure-response models fitted to data from a large epidemiological study of aluminum production workers. For some models, PC depended also on the smoking habit of the cancer patient. RESULTS: Estimation of relative risk by exposure group indicated that over 50% of lung cancers were attributable to coal tar pitch volatiles (PC > 50%) at exposures above 100 micrograms/m3-years benzo(a)pyrene. A linear relative risk model indicated that 50% PC was first achieved at 342.2 micrograms/m3-years benzo(a)pyrene, or 190.1 micrograms/m3-years benzo(a)pyrene according to the upper 95% confidence limit for risk increment. Corresponding figures for a power curve model were 210.3 and 45.9. With these five figures as compensation criteria compensation would have resulted in 31.4%, 2.7%, 19.2%, 15.7%, and 39.2% of cancers studied, compared with an estimated total proportion of cancers studied attributable to coal tar pitch volatiles of 15%-26%. If risks due to coal tar pitch volatiles and smoking multiply, PC does not depend on the amount smoked. If the two risks are additive, however, PC depends on the amount smoked according to a formula, with the figures mentioned applying to an average smoking history (24.4 pack-years). CONCLUSION: Because of its simplicity and because it falls within the range of criteria based on several more sophisticated approaches, we prefer the criterion of 100 micrograms/m3-years, based on the relative risks by exposure group. However, the compensation board of the Canadian province of Quebec, on consideration of these alternatives, has proposed as a criterion that the upper 95% confidence limit of PC for the patient be at least 50%, assuming an additive relative risk model and allowing for their smoking habit.

Aluminum↗
PubMed1983

The relationship of tar content to decline in pulmonary function in cigarette smokers.

The impact of the tar content of cigarettes on pulmonary function was examined in 1,355 men. These men represented 383 current cigarette smokers, 555 former cigarette smokers, and 417 never smokers enrolled in longitudinal study of aging. Current smokers' cigarette exposure was estimated by the number of cigarettes smoked per day and tar content per cigarette. spirometry was performed twice on all subjects at a 5-yr interval. A multiple regression analysis indicated that tar content did not significantly influence baseline levels of forced vital capacity (FVC) or forced expiratory volume in one second (FEV1), after controlling for age, height, and number of cigarettes smoked. Similarly, tar content did not significantly influence follow-up levels of FVC or FEV1, after controlling for age, height, number of cigarettes, and baseline pulmonary function. These data suggest that low tar cigarettes may not protect smokers from an increased rate of decline in pulmonary function.

Adult↗
PubMed2002

Effects of cigarette smoke with different tar contents on hepatic and pulmonary xenobiotic metabolizing enzymes in rats.

The effects of smoke from cigarettes with two different tar contents (32 mg/cigarette, high tar, and 15 mg/cigarette, low tar) on hepatic and pulmonary monooxygenase (MO) activities (aniline 4-hydroxylase [AH]; aminopyrine N-demethylase [AMND]; 7-ethoxyresorufin O-deethylase [EROD]; p-nitroanisole O-demethylase [p-NAOD]), lipid peroxidation (LP) and reduced glutathione (GSH) levels and glutathione S-transferase (GST) activities toward several substrates (1-chloro-2,4-dinitrobenzene [CDNBI; 1,2-dichloro-4-nitrobenzene [DCNB]; ethacrynic acid [EAA]; 1,2-epoxy-3-(p-nitrophenoxy)-propane [ENPP]) were determined in adult male rats. Adult male rats were exposed to smoke of high- or low-tar cigarettes five times a day, with 1-hour intervals, for 3 days in a chamber where smoke and fresh air lead alternatively and were killed 16 hours after the last treatment. Smoke of both high- and low-tar cigarettes (SHTCC and SLTCC) significantly increased hepatic and pulmonary EROD and p-NAOD activities compared to controls. However, the increase noted by SHTCC on pulmonary EROD activity was higher than that of SLTCC. Hepatic AMND and pulmonary AH activities were significantly increased only by SHTCC. LP level was significantly decreased and increased by SHTCC in liver and lung, respectively, whereas it remained unaltered by SLTCC. Only SHTCC significantly increased GSH level in liver. In the lungs, both SHTCC and SLTCC significantly increased GSH level to the same extent. Hepatic GST activity toward EAA was significantly increased by SHTCC but was significantly decreased by SLTCC. ENPP GST activity was significantly decreased by SHTCC and SLTCC in the livers. In the lungs, all the GST activities examined were significantly depressed by SHTCC whereas only GST activity toward DCNB was reduced significantly by SLTCC. These results reveal that the hepatic and pulmonary MOs and GSTs are differentially influenced by SHTCC and SLTCC in rats.

Administration, Inhalation↗
PubMed2004

Estimation of the molecular mass range of the tar from pyrolysis of casein by gas chromatography-mass spectrometry, probe mass spectrometry and size exclusion chromatography with 1-methyl-2-pyrrolidinone as eluent.

Casein has been pyrolysed to obtain a biochar (28.3% yield), with mostly meso- and macro-pore structure, and a liquid tar product of high yield (37.5%) with the balance as gas (20.9%) and water (13.3%). The elemental composition of the casein tar was: C 66.7%, H 8.3%, N 12.1% and O 12.9% (by difference). The tar sample has been characterised by mass spectrometry, gas chromatography (GC)/MS and heated-probe MS, to give molecular mass distributions for comparison with molecular mass ranges indicated by analytical-scale size-exclusion chromatography (SEC). The tar appeared to be completely soluble in 1-methyl-2-pyrrolidinone (NMP), the solvent used for SEC. It appeared to consist mostly of lower molecular mass fractions with elution times at 18-26 min. GC/MS analysis showed the presence of both aliphatic and aromatic nitrogen-containing components. Neither GC/MS nor heated-probe MS were able to detect more than about half the tar components.

Animals↗
PubMed1992

[Mutagenicity and amounts of polycyclic aromatic hydrocarbons in marijuana smoking tar extracted from pipes].

In spite of strict laws prohibiting it, criminal cases involving marijuana abuse are increasing, resulting in a serious social problem in Japan. The most common method of ingestion is smoking, since abusers feel that this method produces quick psychological effects controversial. Marijuana is known to induce psychological addiction, but it's genotoxic effects are still argued. Marijuana smoking tar has been extracted from seized pipes. The amounts of polycyclic aromatic hydrocarbons (PAH) in the tar were weighed and the mutagenic activity was tested. The results are as follows: 1) Five of the seven PAHs were detected in marijuana tar, although benzo(e)pyrene and perylene were not. 2) There was more pyrene than any other substance detected in the tar, with fluoranthene having the next highest concentration. 3) Mutagenic activity was observed in all samples, with relative mutagenic potency ranging from 0.03 to 1.59. 4) The type of smoking pipe and burning temperature may affect the mutagenic activity and the amount of PAH. 5) Since marijuana smoking tar contains carcinogens, promoters, and mutagens, there is a risk of developing cancer just as in the case of tobacco.

Marijuana Smoking↗
PubMed1985

Respiratory effects in relation to estimated tar exposure from current and cumulative cigarette consumption.

Relationships between estimated "tar" exposure from current and past cigarette consumption, were related to respiratory symptoms and function during the seventh survey (1981-1983) of the Tucson epidemiologic study of airways obstructive diseases. Smokers (n = 582; 280 males and 302 females) and exsmokers (n = 621; 345 males and 276 females), answered detailed questions on current and past smoking, and performed flow-volume maneuvers. Cough and phlegm were significantly associated with estimated "tar" exposure from current cigarette consumption. Cough, phlegm, and dyspnea were associated with reported deep inhalation in both sexes, while wheeze was so associated in females. In young smokers (less than 35 years), symptoms were more prevalent in those who had predominantly smoked cigarettes with estimated high "tar." Total exposure was more important in older smokers. Generally, exsmokers showed a lower prevalence of symptoms than smokers. Cross-sectional lung function measurements were significantly related to total estimated "tar" exposure and age. Multiple logistic regressions provided models which helped predict symptoms and lung function impairment in smokers and exsmokers on the basis of estimated "tar" exposure and pack-years of smoking.

Adolescent↗