[Impact of tobacco use on the periodontium--an update (I)--Part 1: Epidemiologic und pathogenetic aspects of tobacco-related periodontal diseases]

This literature review represents the second in a series of articles from the Swiss task force "Smoking--Intervention in the private dental office" on the topic "tobacco use and dental medicine". In this article, the epidemiological background as well as some pathogenetic processes are described and discussed critically for tobacco-related periodontal diseases. Earlier publications confirmed tobacco consumption as a risk factor for periodontal diseases. Over the last few years, oral health research has significantly contributed to the understanding of the mechanisms leading to the deterioration of the hard and soft tissues supporting the teeth. With the recording of the number of cigarettes smoked per day and the amount of years tobacco was used, a dose response relationship was established. Various, potentially significant pathogenic effects of tobacco-related substances may exist on the periodontal tissues, the immune response system or the composition of the oral flora. Moreover, there is reference that tobacco consumption may change the genetically determined susceptibility for periodontal diseases.

Application of headspace solid phase microextraction to qualitative and quantitative analysis of tobacco additives in cigarettes

Cigarettes may contain up to 10% by weight additives which are intended to make them more attractive. A fast and rugged method for a cigarette-screening for additives with medium volatility was developed using automatic headspace solid phase microextraction (HS-SPME) with a 65 microm carbowax-divinylbenzene fiber and gas chromatography-mass spectrometry (GC-MS) with standard electron impact ionisation. In three runs, each cigarette sample was extracted in closed headspace vials using basic, acidic and neutral medium containing 0.5 g NaCl or Na2SO4. Furthermore, the method was optimized for quantitative determination of 17 frequently occurring additives. The practical applicability of the method was demonstrated for cigarettes from 32 brands.

Maternal tobacco smoking and decreased leukocytes, including dendritic cells, in neonates

Maternal smoking in pregnancy is associated with respiratory diseases in the offspring, possibly due to prenatal influences on the developing immune system. We investigated whether maternal smoking in pregnancy was associated with cord blood leukocyte numbers, including precursor dendritic cells, adjusting for concomitant factors. In a prospective healthy birth cohort study, total leukocyte counts were reduced in neonates of smoking mothers [10.7 (8.4-13.0), n=14] compared with nonexposed infants [14.7 (13.7-15.7), n=74, p=0.002] [geometric mean cells x 10(3)/microL (95% confidence interval)]. All leukocyte subsets were decreased, most prominently segmented neutrophils [4.3 (2.8-5.7) versus 6.2 (5.5-6.8), p=0.021], lymphocytes [3.8 (2.9-4.8) versus 5.0 (4.5-5.6), p=0.036], and myeloid precursor dendritic cells [12.7 cells/microL (9.1-17.8) versus 18.3 (15.8-21.2), p=0.055]. These differences persisted after adjustment for possible confounders. Predictors of myeloid precursor dendritic cell numbers in multivariable models were maternal smoking (-5.1 cells/microL, p=0.042), age (-0.5 cells/microL/y, p=0.035), and, marginally, asthma (+8.1 cells/microL, p=0.075). The decrease of all leukocytes in neonates of smoking mothers could be clinically significant and suggests a decreased cell production, increased peripheral recruitment, or retention in bone marrow. Given the importance of dendritic cells in early immune responses, their decrease might reflect an impact of maternal smoking on the developing fetal immune system.

[Effects of tobacco use on systemic health: relevant information for dentistry (II)--part 2: cardiovascular diseases and public health issues]

This is the sixth and concluding part of a series of publications from the Swiss task force named "Smoking - Intervention in the private dental office" on the topic "tobacco use and dental medicine". The focus of this review is the effects of smoking for the development of atherosclerosis as pathohistological correlate for acute coronary syndrome (ACS), arterial occlusive disease, and cerebrovascular diseases (stroke). Additionally, a causal relationship between tobacco use and an increased rate for complications during pregnancy and child birth will be discussed. Next to causal therapy of local and systemic diseases in general, an emphasis must be given to tobacco use prevention and cessation. Finally, important public health issues concerning smoking and tobacco use will be demonstrated, and options to improve the current situation will be presented.

[Effects of tobacco use on general health: relevant information for dentistry (I)--part 1: pulmonary diseases and other malignancies]

This fifth part of a series of publications from the Swiss task force named "Smoking--Intervention in the private dental office" on the topic "tobacco use and dental medicine" focuses on the effects of tobacco use on general health. A significant increase of tobacco use associated morbidity and mortality for many cardiovascular and pulmonary diseases has been well documented in the literature. In this review, the epidemiologic background as well as the pathophysiological fundamentals for tobacco-mediated pulmonary diseases is presented, focusing especially on chronic obstructive pulmonary disease (COPD) and lung cancer. In addition, a causal relationship between nicotine abuse and an increased carcinoma incidence for other malignancies but lung cancer will be discussed. Regarding the evidence in the present literature, it is undisputable that smoking is the most preventable cause for COPD and lung cancer.

Creep and shrinkage behavior of ultra high-performance concrete under compressive loading with varying curing regimes

This Ultra High Performance Concrete research involves observing early-age creep and shrinkage under a compressive load throughout multiple thermal curing regimes. The goal was to mimic the conditions that would be expected of a precast/prestressing plant in the United States, where UHPC beams would be produced quickly to maximize a manufacturing plant’s output. The practice of steam curing green concrete to accelerate compressive strengths for early release of the prestressing tendons was utilized (140°F [60°C], 95% RH, 14 hrs), in addition to the full thermal treatment (195°F [90°C], 95% RH, 48 hrs) while the specimens were under compressive loading. Past experimental studies on creep and shrinkage characteristics of UHPC have only looked at applying a creep load after the thermal treatment had been administered to the specimens, or on ambient cured specimens. However, this research looked at mimicking current U.S. precast/prestressed plant procedures, and thus characterized the creep and shrinkage characteristics of UHPC as it is thermally treated under a compressive load. Michigan Tech has three moveable creep frames to accommodate two loading criteria per frame of 0.2f’ci and 0.6f’ci. Specimens were loaded in the creep frames and moved into a custom built curing chamber at different times, mimicking a precast plant producing several beams throughout the week and applying a thermal cure to all of the beams over the weekend. This thesis presents the effects of creep strain due to the varying curing regimes. An ambient cure regime was used as a baseline for the comparison against the varying thermal curing regimes. In all cases of thermally cured specimens, the compressive creep and shrinkage strains are accelerated to a maximum strain value, and remain consistent after the administration of the thermal cure. An average creep coefficient for specimens subjected to a thermal cure was found to be 1.12 and 0.78 for the high and low load levels, respectively. Precast/pressed plants can expect that simultaneously thermally curing UHPC elements that are produced throughout the week does not impact the post-cure creep coefficient.

Irradiation of intracerebral 9L gliosarcoma by a single array of microplanar x-ray beams from a synchrotron: balance between curing and sparing

The purpose of this work was the understanding of microbeam radiation therapy at the ESRF in order to find the best compromise between curing of tumors and sparing of normal tissues, to obtain a better understanding of survival curves and to report its efficiency. This method uses synchrotron-generated x-ray microbeams. Rats were implanted with 9L gliosarcomas and the tumors were diagnosed by MRI. They were irradiated 14 days after implantation by arrays of 25 microm wide microbeams in unidirectional mode, with a skin entrance dose of 625 Gy. The effect of using 200 or 100 microm center-to-center spacing between the microbeams was compared. The median survival time (post-implantation) was 40 and 67 days at 200 and 100 microm spacing, respectively. However, 72% of rats irradiated at 100 microm spacing showed abnormal clinical signs and weight patterns, whereas only 12% of rats were affected at 200 microm spacing. In parallel, histological lesions of the normal brain were found in the 100 microm series only. Although the increase in lifespan was equal to 273% and 102% for the 100 and 200 microm series, respectively, the 200 microm spacing protocol provides a better sparing of healthy tissue and may prove useful in combination with other radiation modalities or additional drugs.

ACETYL RADICAL IN TOBACCO SMOKE: DETECTION, QUANTIFICATION AND SIMULATION

Free radicals are present in cigarette smoke and can have a negative effect on human health by attacking lipids, nucleic acids, proteins and other biologically important species. However, because of the complexity of the tobacco smoke system and the dynamic nature of radicals, little is known about the identity of the radicals, and debate continues on the mechanisms by which those radicals are produced. In this study, acetyl radicals were trapped from the gas phase using 3-amino-2, 2, 5, 5- tetramethyl-proxyl (3AP) on solid support to form stable 3AP adducts for later analysis by high performance liquid chromatography (HPLC), mass spectrometry/tandem mass spectrometry (MS-MS/MS) and liquid chromatography- mass spectrometry (LC-MS). Simulations of acetyl radical generation were performed using Matlab and the Master Chemical Mechanism (MCM) programs. A range of 10- 150 nmol/cigarette of acetyl radical was measured from gas phase tobacco smoke of both commerial and research cigarettes under several different smoking conditions. More radicals were detected from the puff smoking method compared to continuous flow sampling. Approximately twice as many acetyl radicals were trapped when a GF/F particle filter was placed before the trapping zone. Computational simulations show that NO/NO2 reacts with isoprene, initiating chain reactions to produce a hydroxyl radical, which abstracts hydrogen from acetaldehyde to generate acetyl radical. With initial concentrations of NO, acetaldehyde, and isoprene in a real-world cigarette smoke scenario, these mechanisms can account for the full amount of acetyl radical detected experimentally. This study contributes to the overall understanding of the free radical generation in gas phase cigarette smoke.

A Geological Report on Several Localities in the Northwestern Tobacco Root Mountains

To better acquaint seniors in Geology and mining with actual field practice, the Montana School of Mines offer a course in Geologic Field Mapping, during the three weeks preceding the opening of the fall semester. The first two weeks are spent in actual field mapping of the geologic formations near Whitehall, Montana, while the third week is spent back on the campus compiling data and finishing maps started in the field.

[Smokeless tobacco: a new risk factor for oral health? A review]

Due to migration of different ethnic groups, mainly from Africa and Asia, into Switzerland, many traditional products and habits that have not been seen before were also introduced. Smokeless tobacco (ST)--as one of those habits--is a product of increased use in Switzerland, although no sound epidemiological data are presently available. Numerous studies from North-America, Sweden, Asia and Africa could verify the carcinogenic potency of smokeless tobacco and its effects in the developement of oral cancer and different systemic disorders. For dental professionals and their team it is important to detect ST-associated lesions, and to tell the patients about the potential harmful sequelae of ST products. The present review focusses on the different types of RT products and their effects on oral health.