Policy-relevant differences between secondhand and thirdhand smoke: strengthening protections from involuntary exposure to tobacco smoke pollutants

Starting in the 1970s, individuals, businesses and the public have increasingly benefited from policies prohibiting smoking indoors, saving thousands of lives and billions of dollars in healthcare expenditures. Smokefree policies to protect against secondhand smoke exposure, however, do not fully protect the public from the persistent and toxic chemical residues from tobacco smoke (also known as thirdhand smoke) that linger in indoor environments for years after smoking stops. Nor do these policies address the economic costs that individuals, businesses and the public bear in their attempts to remediate this toxic residue. We discuss policy-relevant differences between secondhand smoke and thirdhand smoke exposure: persistent pollutant reservoirs, pollutant transport, routes of exposure, the time gap between initial cause and effect, and remediation and disposal. We examine four policy considerations to better protect the public from involuntary exposure to tobacco smoke pollutants from all sources. We call for (a) redefining smokefree as free of tobacco smoke pollutants from secondhand and thirdhand smoke; (b) eliminating exemptions to comprehensive smoking bans; (c) identifying indoor environments with significant thirdhand smoke reservoirs; and (d) remediating thirdhand smoke. We use the case of California as an example of how secondhand smoke-protective laws may be strengthened to encompass thirdhand smoke protections. The health risks and economic costs of thirdhand smoke require that smokefree policies, environmental protections, real estate and rental disclosure policies, tenant protections, and consumer protection laws be strengthened to ensure that the public is fully protected from and informed about the risks of thirdhand smoke exposure.

Dermal thirdhand smoke exposure induces oxidative damage, initiates skin inflammatory markers, and adversely alters the human plasma proteome

Background

Thirdhand smoke (THS) exposure correlated with significant metabolism of carcinogenic chemicals and the potential to cause detrimental health effects. Human harm research of THS exposure is limited to one other study and overall, there is a general lack of knowledge of the human health responses to THS exposure.

Methods

This was a clinical investigation to evaluate the health effects of 3-h dermal THS exposure from urine and plasma. 10 healthy, non-smoking subjects were recruited for dermal exposure for 3 h exposed to clothing impregnated with filtered clean air or THS. Exposures to clean air or THS occurred 20-30 days apart.

Findings

In THS-exposed group, there was a significant elevation of urinary 8-OHdG, 8-isoprostane, protein carbonyls. The THS 3-h exposure identified proteomics pathways of inflammatory response (p=2.18 × 10⁻⁸), adhesion of blood cells (p=2.23 × 10⁻⁸), atherosclerosis (p=2.78 × 10⁻⁹), and lichen planus (p=1.77 × 10⁻⁸). Nine canonical pathways were significantly activated including leukocyte extravasation signaling (z-score=3.0), and production of nitric oxide and reactive oxygen in macrophages (z-score=2.1). The THS 22-h proteomics pathways revealed inflammation of organ (p=3.09 × 10⁻⁸), keratinization of the epidermis (p=4.0 × 10⁻⁷), plaque psoriasis (p=5.31 × 10⁻⁷), and dermatitis (p=6.0 × 10⁻⁷). Two activated canonical pathways were production of nitric oxide and reactive oxygen in macrophages (z-score=2.646), and IL-8 signaling (z-score=2.0).

Interpretation

This is a clinical study demonstrating that acute dermal exposure to THS mimics the harmful effects of cigarette smoking, alters the human plasma proteome, initiates mechanisms of skin inflammatory disease, and elevates urinary biomarkers of oxidative harm.

Funding

Funding was provided by the Tobacco Related Disease Research Program (TRDRP) 24RT-0037 TRDRP, 24RT-0039 TRDRP, and 28PT-0081 TRDRP.

Abstract 236: Aldehydes in Cigarette Smoke Impair Vascular Endothelial Function

Introduction: Exposure to tobacco and marijuana smoke impairs vascular endothelial function. While the particulate phase of smoke is heavily implicated, the role of volatile constituents is unclear. Smoke contains aldehydes, which are known to cause endothelial dysfunction. We explored whether two aldehydes found in smoke, acrolein and acetaldehyde, can induce endothelial dysfunction.

Hypothesis: Aldehydes in smoke impair endothelial function.

Methods: We exposed 4 groups of anesthetized rats to 3 ppm acrolein and 10-11.5 ppm acetaldehyde gases (concentrations relevant to levels in secondhand smoke), Marlboro Red cigarette sidestream smoke at modest levels (600 μg/m 3 PM2.5) as a positive control, and clean air through the gas generation system as a negative control. Exposure was continuous for 10 minutes. Endothelial function (flow-mediated dilation; FMD) was quantified pre- and post-exposure by measuring femoral artery diameter with ultrasound before and after 5 min of transient ischemia and expressed as % vasodilation.

Results: Impairment of FMD was observed for acrolein (10.8±1.7(SD)% vs. 5.8±2.9%, p=.001), acetaldehyde (8.8±2.0% vs. 6.0±2.5%, p=.001), and cigarette smoke (9.4±2.9% vs. 5.8±2.0%, p=.002), but not for air (7.9±2.0% vs. 9±3.2%, p=.44) (figure; each colored line denotes a rat pre- and post-exposure; bars denote means).

Conclusions: Acrolein and acetaldehyde at levels found in secondhand smoke impair endothelial function. Our results suggest that despite a potential role of particles, volatile aldehydes may mediate part of the endothelial dysfunction caused by exposure to smoke.

Thirdhand Smoke at Philip Morris

INTRODUCTION

Thirdhand cigarette smoke is the fraction of cigarette smoke that remains in the environment long after a cigarette is extinguished.

METHODS

The Truth Tobacco Industry Documents collection at the University of California San Francisco was searched for information on thirdhand smoke.

RESULTS

In 1991, scientists at Philip Morris Inc conducted some of the first studies on thirdhand cigarette smoke. For 110 days, 8 hours a day, they ran sidestream cigarette smoke through a 30 m3 room that contained carpet, curtain, and textured wallpaper. The room was ventilated with clean air every night. By comparing the chemicals in the air during the 8-hour smoking period and during the clean air ventilation period, they showed that some smoke chemicals persist in the air 12 hours after smoking. By extracting the nicotine and nitrosamines from samples of the carpet, curtain, and wallpaper, they found that high concentrations of nicotine and the carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) persisted in the room for more than 50 days; that surface chemistry affected nitrosamine concentrations; and that the concentration of NNK in the room, 110 days after the last cigarette was extinguished, could exceed the mass of NNK that entered the room as smoke.

CONCLUSIONS

These data, from a controlled environment where the total number of cigarettes smoked is known, provide further evidence that cigarette smoke chemicals remain in the environment for months after smoking, that they reemit back into the air, and that they react to form new toxins and carcinogens. Smoke-free policies are the best method to reduce exposure to thirdhand smoke.

IMPLICATIONS

This unpublished, original research from Philip Morris Inc demonstrates that majority of the nicotine and tobacco-specific nitrosamines in the secondhand smoke from each cigarette smoked indoors remains on indoor surfaces for months after the cigarette is extinguished. It also demonstrates that elevated concentrations of nicotine, ammonia, formaldehyde, and the gas-phase nitrosamine, N-nitrosopyrrolidine, can be found in the air for more than 12 hours after smoking; that surface chemistry affects nitrosamine formation and persistence; and that the amount of the carcinogenic nitrosamine NNK that persists months after smoking ends can exceed the amount that actually came out of the cigarettes.

Experimental Acute Exposure to Thirdhand Smoke and Changes in the Human Nasal Epithelial Transcriptome: A Randomized Clinical Trial

IMPORTANCE

No previous studies have shown that acute inhalation of thirdhand smoke (THS) activates stress and survival pathways in the human nasal epithelium.

OBJECTIVE

To evaluate gene expression in the nasal epithelium of nonsmoking women following acute inhalation of clean air and THS.

DESIGN, SETTING, AND PARTICIPANTS

Nasal epithelium samples were obtained from participants in a randomized clinical trial (2011-2015) on the health effects of inhaled THS. In a crossover design, participants were exposed, head only, to THS and to conditioned, filtered air in a laboratory setting. The order of exposures was randomized and exposures were separated by at least 21 days. Ribonucleic acid was obtained from a subset of 4 healthy, nonsmoking women.

EXPOSURES

By chance, women in the subset were randomized to receive clean air exposure first and THS exposure second. Exposures lasted 3 hours.

MAIN OUTCOMES AND MEASURES

Differentially expressed genes were identified using RNA sequencing with a false-discovery rate less than 0.1.

RESULTS

Participants were 4 healthy, nonsmoking women aged 27 to 49 years (mean [SD] age, 42 [10.2] years) with no chronic diseases. A total of 389 differentially expressed genes were identified in nasal epithelium exposed to THS, while only 2 genes, which were not studied further, were affected by clean air. Enriched gene ontology terms associated with stress-induced mitochondrial hyperfusion were identified, such as respiratory electron transport chain (q = 2.84 × 10-3) and mitochondrial inner membrane (q = 7.21 × 10-6). Reactome pathway analysis identified terms associated with upregulation of DNA repair mechanisms, such as nucleotide excision repair (q = 1.05 × 10-2). Enrichment analyses using ingenuity pathway analysis identified canonical pathways related to stress-induced mitochondrial hyperfusion (eg, increased oxidative phosphorylation) (P = .001), oxidative stress (eg, glutathione depletion phase II reactions) (P = .04), and cell survival (z score = 5.026).

CONCLUSIONS AND RELEVANCE

This study found that acute inhalation of THS caused cell stress that led to the activation of survival pathways. Some responses were consistent with stress-induced mitochondrial hyperfusion and similar to those demonstrated previously in vitro. These data may be valuable to physicians treating patients exposed to THS and may aid in formulating regulations for the remediation of THS-contaminated environments.

Cardiovascular injury induced by tobacco products: assessment of risk factors and biomarkers of harm. A Tobacco Centers of Regulatory Science compilation

Although substantial evidence shows that smoking is positively and robustly associated with cardiovascular disease (CVD), the CVD risk associated with the use of new and emerging tobacco products, such as electronic cigarettes, hookah, and heat-not-burn products, remains unclear. This uncertainty stems from lack of knowledge on how the use of these products affects cardiovascular health. Cardiovascular injury associated with the use of new tobacco products could be evaluated by measuring changes in biomarkers of cardiovascular harm that are sensitive to the use of combustible cigarettes. Such cardiovascular injury could be indexed at several levels. Preclinical changes contributing to the pathogenesis of disease could be monitored by measuring changes in systemic inflammation and oxidative stress, organ-specific dysfunctions could be gauged by measuring endothelial function (flow-mediated dilation), platelet aggregation, and arterial stiffness, and organ-specific injury could be evaluated by measuring endothelial microparticles and platelet-leukocyte aggregates. Classical risk factors, such as blood pressure, circulating lipoproteins, and insulin resistance, provide robust estimates of risk, and subclinical disease progression could be followed by measuring coronary artery Ca2+ and carotid intima-media thickness. Given that several of these biomarkers are well-established predictors of major cardiovascular events, the association of these biomarkers with the use of new and emerging tobacco products could be indicative of both individual and population-level CVD risk associated with the use of these products. Differential effects of tobacco products (conventional vs. new and emerging products) on different indexes of cardiovascular injury could also provide insights into mechanisms by which they induce cardiovascular harm.

Novel Microscalpels for Removing Proximal Composite Resin Overhangs on Class II Restorations

Introduction:

Limited access to interdental spaces complicates removal of excess material when placing class II composite resin restorations. Evidence-based recommendations on interproximal finishing are rare. We present novel microscalpels for this indication. The aim of the study was to test their fracture strength and cutting ability and to compare microscalpels with the use of a scaler, oscillating devices (G5-ProShape, G5-Proxocare), finishing strips and scalpels of sizes 12, 15, and 21 in a standardized in vitro model.

Methods and Materials:

Fracture strength (LOAD) and cutting forces (CUT) of microscalpels were evaluated at different angles (15, 30, 60, and 75 degrees; n=30 each) in a universal testing machine. Devices were compared in vitro using standardized composite overhangs. Marginal quality (QUAL; n=30) and quantity of excess/deficit (QUAN; n=30) were evaluated using scanning electron microscopy (SEM) for each device (explorative data analysis, Student t-test or analysis of variance; post hoc Scheffé).

Results:

Microscalpels showed the highest LOAD (95.8 [5.0] N) (mean [standard deviation]) and easiest cutting (CUT) (7.6 [1.5]) at 15 degrees. At all angles, LOAD was significantly higher than CUT (p<0.001). Perfect margins were seen most often with scalpel size 12 (QUAL: 37% relative frequency), while most excess (73.4%) was observed with finishing strips. QUAN was lowest with microscalpels (19.3 [4.4] μm) and highest with finishing strips (116.0 [18.8]). Use of scalers led to fractures and crack formation.

Conclusion:

Microscalpels are able to cut composite at a lower force than necessary to fracture the blades at all angles. Small and/or curved scalpels yield the best-quality margins.

Taxonomy of the super-cryptic Hyperolius nasutus group of long reed frogs of Africa (Anura: Hyperoliidae), with descriptions of six new species

Specimens from across the range of the Hyperolius nasutus species group were sequenced for two mitochondrial genes and one nuclear gene. Advertisement calls were recorded from the same specimens where possible, and morphological characters were compared. Bayesian inference and maximum likelihood produced a tree indicating 16 clades. The clades show little or no overlap in combinations of 16S sequence difference, shared tyr haplotypes, advertisement call parameters, snout profiles and webbing. On the basis of these data we recognise H. acuticeps, H. adspersus, H. benguellensis, H. dartevellei, H. igbettensis, H. nasutus, H. nasicus, H. poweri, H. viridis and describe six new species: Hyperolius friedemanni sp. nov. Mercurio & Rödel, Hyperolius howelli sp. nov. Du Preez & Channing, Hyperolius inyangae sp. nov. Channing, Hyperolious jacobseni sp. nov. Channing, Hyperolius rwandae sp. nov. Dehling, Sinsch, R6del & Channing, and Hyperolius lupiroensis sp. nov. Channing. Hyperolius lamottei is confirmed to be outside the H. nasutus group clade. Hyperolius granulatus, H. oxyrhynchus, H. punctulatus and H. sagitta are assigned as junior synonyms. As our results are based on a small number of specimens, these hypotheses await testing with larger sample sizes and more characters. A species distribution model suggests where outlier populations might be found.

Thirdhand smoke causes DNA damage in human cells

Exposure to thirdhand smoke (THS) is a newly described health risk. Evidence supports its widespread presence in indoor environments. However, its genotoxic potential, a critical aspect in risk assessment, is virtually untested. An important characteristic of THS is its ability to undergo chemical transformations during aging periods, as demonstrated in a recent study showing that sorbed nicotine reacts with the indoor pollutant nitrous acid (HONO) to form tobacco-specific nitrosamines (TSNAs) such as 4-(methylnitrosamino)-4-(3-pyridyl)butanal (NNA) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). The goal of this study was to assess the genotoxicity of THS in human cell lines using two in vitro assays. THS was generated in laboratory systems that simulated short (acute)- and long (chronic)-term exposures. Analysis by liquid chromatography-tandem mass spectrometry quantified TSNAs and common tobacco alkaloids in extracts of THS that had sorbed onto cellulose substrates. Exposure of human HepG2 cells to either acute or chronic THS for 24h resulted in significant increases in DNA strand breaks in the alkaline Comet assay. Cell cultures exposed to NNA alone showed significantly higher levels of DNA damage in the same assay. NNA is absent in freshly emitted secondhand smoke, but it is the main TSNA formed in THS when nicotine reacts with HONO long after smoking takes place. The long amplicon-quantitative PCR assay quantified significantly higher levels of oxidative DNA damage in hypoxanthine phosphoribosyltransferase 1 (HPRT) and polymerase β (POLB) genes of cultured human cells exposed to chronic THS for 24h compared with untreated cells, suggesting that THS exposure is related to increased oxidative stress and could be an important contributing factor in THS-mediated toxicity. The findings of this study demonstrate for the first time that exposure to THS is genotoxic in human cell lines.

Muscle pathologies after cervical spine distortion-like exposure--a porcine model

OBJECTIVE

Histological evaluation of porcine posterior cervical muscles after a forceful translational and extensional head retraction simulating high-speed rear end impact.

METHODS

Four anesthetized pigs were exposed to a cervical spine distortion (CSD)-like motion in a lying position. After 2 different survival times of 4 and 6 h (posttrauma), the pigs were euthanized and tissue sampling of posterior cervical muscles was performed. A standard histological staining method involving paraffin-embedded sections was used to analyze the muscles, focusing on injury signs like hemorrhage and inflammatory cell reaction. A pig that was not subjected to impact was used as a control pig and was subjected to the same procedure to exclude any potential artifacts from the autopsy.

RESULTS

The differentiation of 8 different posterior neck muscles in the dissection process was successful in more than 50 percent for each muscle of interest. Staining and valid analysis was possible from all extracted samples. Muscle injuries to the deepest posterior neck muscles could be found, especially in the musculus obliquus samples, which showed laminar bleedings in 4 out of 4 samples. In addition, in 4 out of 4 samples we were able to see increased cellular reactions. The splenius muscle also showed bleeding in all 4 samples. All animals showed muscle injury signs in more than three quarters of analyzed neck muscles. Differences between survival times of 4 and 6 h in terms of muscular injury were not of primary interest and could not be found.

CONCLUSIONS

By simulating a CSD-like motion we were able to confirm injuries in the posterior cervical muscles under severe loading conditions. Further studies need to be conducted to determine whether these muscle injuries also occur under lower exposure forces.

Thirdhand tobacco smoke: emerging evidence and arguments for a multidisciplinary research agenda

BACKGROUND

There is broad consensus regarding the health impact of tobacco use and secondhand smoke exposure, yet considerable ambiguity exists about the nature and consequences of thirdhand smoke (THS).

OBJECTIVES

We introduce definitions of THS and THS exposure and review recent findings about constituents, indoor sorption-desorption dynamics, and transformations of THS; distribution and persistence of THS in residential settings; implications for pathways of exposure; potential clinical significance and health effects; and behavioral and policy issues that affect and are affected by THS.

DISCUSSION

Physical and chemical transformations of tobacco smoke pollutants take place over time scales ranging from seconds to months and include the creation of secondary pollutants that in some cases are more toxic (e.g., tobacco-specific nitrosamines). THS persists in real-world residential settings in the air, dust, and surfaces and is associated with elevated levels of nicotine on hands and cotinine in urine of nonsmokers residing in homes previously occupied by smokers. Much still needs to be learned about the chemistry, exposure, toxicology, health risks, and policy implications of THS.

CONCLUSION

The existing evidence on THS provides strong support for pursuing a programmatic research agenda to close gaps in our current understanding of the chemistry, exposure, toxicology, and health effects of THS, as well as its behavioral, economic, and sociocultural considerations and consequences. Such a research agenda is necessary to illuminate the role of THS in existing and future tobacco control efforts to decrease smoking initiation and smoking levels, to increase cessation attempts and sustained cessation, and to reduce the cumulative effects of tobacco use on morbidity and mortality.

Pilot study of compliance with healthcare facility smoking laws in Georgia

In 2003 Georgian Parliament restricted smoking in all healthcare facilities to designated smoking areas. Observed compliance has been low. This quantitative study of airborne nicotine and particulate concentrations in nine healthcare facilities in Tbilisi and Region Kakheti in February, 2007 was a pilot to assess the degree of noncompliance with the law and to identify potential strategies for increasing compliance. Passive sampling of nicotine and active sampling of PM(2.5) in selected healthcare facilities. None of the facilities we monitored had designated smoking areas that met the legal requirements. Fifty of the 51 samplers registered concentrations of nicotine above the level of detection. Of these, 52% showed concentrations below 1 microg/m(3) nicotine, 27% showed concentrations between 1 and 5 microg/m(3) and 20% were above 5 microg/m(3). The highest nicotine levels were found in medical staff offices, and in undesignated "informal smoking areas". These data support qualitative observations that the law restricting smoking in Georgian healthcare facilities to designated areas is poorly enforced and does not protect patients and employees from secondhand smoke. These findings suggest that Georgian law should be changed to make all healthcare institutions smoke free environments and that there is a need for tobacco control programs targeted at medical professionals in Georgia.

Sidestream cigarette smoke toxicity increases with aging and exposure duration

OBJECTIVES

To determine the effects of aging on the toxicity of sidestream tobacco smoke, the complex chemical mixture that enters the air from the lit end of burning cigarettes and constitutes the vast bulk of secondhand smoke.

DESIGN

Statistical analysis of data from controlled experimental exposures of Sprague Dawley rats to fresh and aged (for more than 30 minutes) sidestream smoke for up to 90 days followed by histological sectioning of the respiratory epithelium. The data were obtained from a series of experiments conducted at Philip Morris' formerly secret INBIFO (Institut für Biologische Forschung) laboratory in Germany.

RESULTS

Using total particulate material as the measure of smoke exposure, aging sidestream cigarette smoke for at least 30 minutes increases its toxicity fourfold for 21 day exposures and doubles the toxicity for 90 day exposures, relative to fresh sidestream smoke.

CONCLUSIONS

These results help explain the relatively large biological effects of secondhand smoke compared to equivalent mass doses of mainstream smoke.

Scientific analysis of second-hand smoke by the tobacco industry, 1929-1972

The 1972 U.S. surgeon general's report The Health Consequences of Smoking was the first to include a warning about exposure to second-hand smoke. Because the tobacco industry has a record of withholding the results of their research from the public, we searched the internal tobacco industry documents and compared internal industry research on second-hand smoke to what the industry published in the open scientific literature through 1972. We found chemical analyses, sensory evaluations, and discussions of sidestream cigarette smoke (the smoke emitted by the cigarette between puffs, the main component of second-hand smoke), beginning in 1929. American Tobacco Company research in the 1930s indicated that, compared with mainstream smoke, sidestream smoke was produced in larger quantities and contained, per cigarette, 2 times more nicotine and 12 times more ammonia. Research funded by the Tobacco Industry Research Committee in the 1950s revealed that sidestream smoke contained, per unit cigarette, higher concentrations of carcinogenic polycyclic aromatic hydrocarbons, per unit mass, including four times more 3,4 benzopyrene. In 1956 and 1957, respectively, Philip Morris and R. J. Reynolds also began to research sidestream smoke. In 1961, Philip Morris began to do sensory evaluation and modification of sidestream odor during product development. This sensory evaluation of sidestream smoke was the first biological testing of sidestream smoke by a tobacco company. Prior to the release of the 1972 U.S. surgeon general's report, the tobacco industry published the majority of its findings in the open scientific literature and does not appear to have perceived second-hand smoke as a threat to human health.

Philip Morris toxicological experiments with fresh sidestream smoke: more toxic than mainstream smoke

BACKGROUND

Exposure to secondhand smoke causes lung cancer; however, there are little data in the open literature on the in vivo toxicology of fresh sidestream cigarette smoke to guide the debate about smoke-free workplaces and public places.

OBJECTIVE

To investigate the unpublished in vivo research on sidestream cigarette smoke done by Philip Morris Tobacco Company during the 1980s at its Institut für Biologische Forschung (INBIFO).

METHODS

Analysis of internal tobacco industry documents now available at the University of California San Francisco Legacy Tobacco Documents Library and other websites.

RESULTS

Inhaled fresh sidestream cigarette smoke is approximately four times more toxic per gram total particulate matter (TPM) than mainstream cigarette smoke. Sidestream condensate is approximately three times more toxic per gram and two to six times more tumourigenic per gram than mainstream condensate by dermal application. The gas/vapour phase of sidestream smoke is responsible for most of the sensory irritation and respiratory tract epithelium damage. Fresh sidestream smoke inhibits normal weight gain in developing animals. In a 21 day exposure, fresh sidestream smoke can cause damage to the respiratory epithelium at concentrations of 2 microg/l TPM. Damage to the respiratory epithelium increases with longer exposures. The toxicity of whole sidestream smoke is higher than the sum of the toxicities of its major constituents.

CONCLUSION

Fresh sidestream smoke at concentrations commonly encountered indoors is well above a 2 microg/m3 reference concentration (the level at which acute effects are unlikely to occur), calculated from the results of the INBIFO studies, that defines acute toxicity to humans. Smoke-free public places and workplaces are the only practical way to protect the public health from the toxins in sidestream smoke.

DBH*444G/A polymorphism of the dopamine-β-hydroxylase gene is associated with alcoholism but not with severe alcohol withdrawal symptoms

As the enzyme dopamine-beta-hydroxylase (DbetaH) converts dopamine to norepinephrine and both transmitters seem to be involved in the pathology of alcoholism and severe alcohol withdrawal symptoms, the gene encoding DbetaH (DBH) was applied to explore the genetic background of alcoholism and severe withdrawal symptoms. 102 healthy control subjects and 208 alcoholics, including 97 patients with a history of mild withdrawal symptoms, 57 with a history of alcohol withdrawal seizure (AWS) and 82 with a history of delirium tremens (DT) were genotyped for the DBH*444G/A polymorphism revealing a significantly elevated frequency of genotypes carrying the A-allele (p = 0.02; after Bonferroni adjustment for multiple tests) in alcoholics compared to healthy controls. Frequencies of alleles and genotypes of individuals with mild withdrawal symptoms did not differ significantly from those of patients with DT or AWS.

Severity of alcohol withdrawal symptoms and the T1128C polymorphism of the neuropeptide Y gene

Neuropeptide Y (NPY) modulates ethanol drinking in rodents. The C-allele of the T1128C polymorphism of the human NPY gene has been previously associated with elevated alcohol consumption in a Finn population study. The present study tested the hypothesis that the T1128C polymorphism is associated with the diagnosis of alcoholism or with severe forms of alcohol withdrawal and with the daily consumption of alcohol in alcoholic patients. After PCR-RFLP genotyping, two groups of alcoholics with severe withdrawal symptoms (delirium tremens, n = 83; withdrawal seizures, n = 65) were compared to alcoholics with mild withdrawal symptoms (n = 97). An elevated frequency of the C-allele in the individuals with severe withdrawal symptoms was found, however not reaching statistical significance. Further a group of healthy controls (n = 102) was compared to all included alcoholics (n = 216) revealing no significant result. Alcoholics carrying the C-allele reported a non significantly elevated daily consumption of alcohol compared to alcoholics with the TT genotype. All alcohol dependent subjects with severe withdrawal symptoms revealed a significantly elevated daily consumption of alcohol compared to alcoholics with only mild withdrawal symptoms. More studies on different ethnic groups are needed to further elucidate the influence of the NPY gene on alcoholism.

Muir-Torre syndrome: a case for surveillance of the ampulla of Vater

A 64-year-old man with Muir-Torre syndrome (MTS), a condition characterized by the association of multiple sebaceous tumours and kerato-acanthomas with internal malignancies, developed a carcinoma of the ampulla of Vater. This is the 2nd reported ampullary carcinoma in 205 reported cases of MTS, suggesting a higher prevalence in MTS patients than in the general population. As an ampullary carcinoma is potentially amenable to surgical resection, particularly when detected early, patients with MTS should undergo regular endoscopic surveillance of the ampulla of Vater.

Cortical responses to object-motion and visually-induced self-motion perception

We investigated the spatiotemporal cortical dynamics during the perception of object-motion and visually-induced self-motion perception in six normal subjects, using a 143-channel neuromagnetometer. Object-motion specific tasks evoked early transient activity over the right temporooccipital cortex, while self-motion perception, or vection, additionally was followed by sustained bilateral activity in the temporoparietal area. The specific signal distributions suggest to represent the different perceptual modes of object-motion and self-motion sensation.

Lingual vascular canals of the mandible: evaluation with dental CT

PURPOSE

To evaluate whether dental computed tomography (CT) can depict the frequency, diameter, position, and direction of vessels entering the mandible through lingual bone canals.

MATERIALS AND METHODS

Thirty-two consecutive patients underwent preimplantation CT of the lower jaw and examination for the presence, number, location, diameter, and direction of lingual canals entering the mandible. In addition, three cadaver mandibles were investigated with dental CT and subsequently dissected to confirm the CT findings.

RESULTS

All patients demonstrated at least one lingual vascular canal, and 20 (63%) had multiple (two to five) canals. The typical lingual canal locations were the midline of the mandible and the premolar region. The mean diameter of the lingual canals was 0.7 mm +/- 0.3 (SD) (range, 0.4--1.5 mm) in the midline and 0.6 mm +/- 0.2 (range, 0.3--1.2 mm) in both premolar regions of the mandible. Examination results in the three cadaver mandibles confirmed the CT findings in those mandibles.

CONCLUSION

Dental CT can depict the occurrence, position, and size of the lingual vascular canals of the mandible. Radiologists should be aware of this anatomic feature and its possible implications.

Preoperative fast MRI of brain tumors using three-dimensional segmented echo planar imaging compared to three-dimensional gradient echo technique

The purpose of this study was to compare the diagnostic efficacy of a newly developed T(1)-weighted three-dimensional segmented echo planar imaging (3D EPI) sequence versus a conventional T(1)-weighted three dimensional spoiled gradient echo (3D GRE) sequence in the evaluation of brain tumors. Forty-four patients with cerebral tumors and infections were examined on a 1.0 T MR unit with 23 mT/m gradient strength. The total scan time for the T(1) 3D EPI sequence was 2 min 12 s, and for a conventional 3D GRE sequence it was 4 min 59 s. Both sequences were performed after administration of a contrast agent. The images were analyzed by three radiologists. Image assessment criteria included lesion conspicuity, contrast between different types of normal tissue, and image artifacts. In addition, signal-to-noise and contrast-to-noise-ratio (C/N) were calculated. The gray-white differentiation and C/N ratio of 3D EPI were found to be inferior to conventional 3D GRE images, but the difference was not statistically significant. In the qualitative comparison, lesion detection and conspicuity of 3D EPI images and conventional 3D GRE images were similar, but a tow-fold reduction of the scanning time was obtained. With the 3D EPI technique, a 50% scan time reduction could be achieved with acceptable image quality compared to conventional 3D GRE. Thus, the 3D EPI technique could replace conventional 3D GRE in the preoperative imaging of brain.

Detection of focal hepatic lesions: comparison of unenhanced and SHU 555 A-enhanced MR imaging versus biphasic helical CTAP

The purpose of this study was to compare the diagnostic sensitivity of unenhanced magnetic resonance (MR) imaging, and MR imaging with a new superparamagnetic iron oxide (SPIO)-enhanced contrast agent (SHU 555 A) with biphasic helical computed tomography during arterial portography (CTAP) in patients with focal liver lesions. Eighteen patients with a total of 91 (78 malignant, 13 benign) proven liver lesions underwent unenhanced short tau inversion recovery (STIR), T2-weighted (T2-w) TSE, and SHU 555 A-enhanced T2-w turbo spin-echo (TSE) MR imaging and biphasic helical CTAP. The standard of reference was histopathologic analysis of resected specimens in 59 lesions, intraoperative ultrasound with biopsy in 20 lesions, and CT-guided biopsy and follow-up in 12 lesions. Diagnostic performance of the imaging modalities was compared quantitatively and qualitatively by assessing lesion involvement in liver segments. There were 68 lesions detected on unenhanced T2-w TSE, which resulted in a sensitivity of 75%. With the STIR sequence, 76 lesions were detected, for a sensitivity of 84%, and with SHU 555 A-enhanced MRI, 84 lesions were detected, for a sensitivity of 92%. CTAP detected 88 lesions, for a sensitivity of 97%. The accuracy for unenhanced T2-w TSE was 98%, for STIR 99%, for enhanced-MRI 100%, and for CTAP 95%. The specificity was 100% for SHU 555 A-enhanced MRI and 95% for CTAP. SHU 555 A-enhanced MRI was superior to nonenhanced MRI (P < 0.05) and equivalent to CTAP in terms of sensitivity. Due to the absence of false-positive results on SHU 555 A-enhanced MRI, the specificity and accuracy of enhanced MRI were higher than those of CTAP, but the difference was not statistically significant (P = 0.134).

Ultrafast magnetic resonance imaging of the brain

The purpose of this study was to compare the diagnostic efficacy of single shot fast spin echo sequence (SSh-FSE), and single shot GRASE-sequence (SSh-GRASE) to the conventional T(2)-weighted fast spin echo-sequence (T(2)-FSE) in the imaging of brain disorders. Thirty three patients with high signal intensity lesions on T(2)-weighted images (n = 28), or intracerebral hemorrhage (n = 5), were examined on a 1.0 T MR scanner, with 23 mT/m gradient strength. The scan time for the conventional T(2)-FSE-sequence was 2 min 57 s, the scan time for the single shot-FSE-, and single shot-GRASE-sequences was 11 sec, and 17 sec, respectively. Twenty-one patients remained still during the examination, whereas 12 could not stay still with consecutive marked motion artifacts. Images were reviewed by three radiologists. Lesion conspicuity, image quality, and artifacts were scored on a subjective scale. Signal-to-noise ratios of lesions and normal tissue and contrast-to-noise ratios (CNR) were measured by region of interest (ROI). In the patient group without motion artifacts conspicuity for lesions > or =5 mm did not show a significant difference on conventional T(2)-FSE, single shot-FSE and single shot-GRASE. Detectability of the smaller lesions was significantly inferior on single shot-FSE-, and single shot-GRASE-sequences in artifact free images. For the patient group with motion artifacts SSh-FSE and SSh-GRASE were markedly superior to the conventional T(2)-FSE. Grey-white differentiation was better on conventional T(2)-FSE. Physiologic ferritin as well as pathologic hemosiderin depositions were slightly darker and therefore better visible on SSh-GRASE than on SSh-FSE. Conventional T(2)-FSE showed significantly more artifacts. In conclusion, SSh-FSE and SSh-GRASE imaging can be used for rapid imaging of the brain in those patients who are claustrophobic or in patients with involuntary movements due to extrapyramidal disorders, as well as in children in whom anesthesia is contraindicated or sedation is not possible.

Atypical appearance of elastofibroma dorsi on MRI: case reports and review of the literature

Three patients with histologically proven elastofibroma dorsi underwent MRI, using T1-weighted, T2-weighted, STIR (short inversion time inversion recovery), and contrast-enhanced SE sequences. All lesions typically displayed low signal intensity masses interspersed with areas of high signal intensity on T1- and T2-weighted SE images. Contrary to prior reports, two patients showed marked enhancement of the mass after administration of Gd-DTPA. Although the characteristic signal intensity on conventional T1- and T2-weighted images may lead to the early diagnosis of this rare tumor, radiologists should be aware that marked contrast enhancement may be representative in elastofibroma dorsi.

[Magnetic resonance tomography in dental radiology (dental MRI)]

PURPOSE

To demonstrate the usefulness of Dental-MRT for imaging of anatomic and pathologic conditions of the mandible and maxilla.

METHODS

Seven healthy volunteers, 5 patients with pulpitis, 9 patients with dentigerous cysts, 5 patients after tooth transplantation and 12 patients with atrophic mandibles were evaluated. Studies of the jaws using axial T1- and T2-weighted gradient echo and spin echo sequences in 2D and 3D technique have been to performed. The acquired images were reconstructed with a standard dental software package on a workstation as panoramic and cross sectional views of the mandible or maxilla.

RESULTS

The entire maxilla and mandibula, teeth, dental pulp and the content of the mandibular canal were well depicted. Patients with inflammatory disease of the pulp chamber demonstrate bone marrow edema in the periapical region. Dentigerous cysts and their relation to the surrounding structures are clearly shown. After contrast media application marked enhancement of the dental pulp can be found.

CONCLUSION

Dental-MRT provides a valuable tool for visualization and detection of dental diseases.

Elastofibroma dorsi. Study of two cases and magnetic resonance imaging findings

Two cases of elastofibroma dorsi (one bilateral, one unilateral) in the periscapular and infrascapular region of two male patients are described. Magnetic resonance imaging revealed a tumorous mass of typical low signal intensity with interspersed areas of high signal intensity on T1 and T2 weighted spin echo sequences. In contrast to previous studies that reported mild enhancement within elastofibromas after administration of intravenous contrast agent, marked enhancement in one of two elastofibromas was found. This is considered to be atypical for benign lesions. After biopsy and histopathologic examination, an intended marginal resection was performed in both cases. Laboratory values, radiographs, and computed tomography may not be helpful in differentiating elastofibroma from malignant tumors. In addition to careful clinical investigation, magnetic resonance imaging is the method of choice leading to a presumptive diagnosis. Because marked enhancement on contrast agent images was observed, which is characteristic for malignant tumors, one should be aware that this feature does not exclude the presence of elastofibroma. Accurate diagnosis should be made preferably by biopsy and histopathologic evaluation before additional treatment is administered. Marginal resection is curative in patients with symptoms. Despite its low incidence, this pseudotumoral lesion should be known generally to differentiate it from malignant tumors and to avoid unnecessary wide or radical surgery.

Virchow-Robin spaces in childhood migraine

Virchow-Robin spaces (VRS) are pia-lined extensions of the subarachnoid space which surround penetrating arteries as they enter the brain on its surface. Using high-resolution MRI, which shows small penetrating arteries, we studied a possible association of accentuated VRS in children with tension-type headache (TTH) or migraine. We studied 58 children aged 3-14 years (mean 10.8 years) with a clinical diagnosis of migraine (31) or TTH (27), who underwent cerebral MRI, and 30 headache-free patients of the same age (mean 10.2 years) and 30 adult migraineurs with postpubertal onset of symptoms, who served as controls. The images were reviewed for structural abnormalities in the regions of the small penetrating arteries. Accentuated VRS were found in 61% of the children with migrainous headaches and in 22% of children of those with TTH. Prominent VRS were seen in 27% of the control children and in only 13% of the adults. Small infarcts and gliosis were rare in children with or without headache, but were seen in 30% of the adult migraineurs. Our findings show that accentuated VRS are significantly more common in children with migraine than in those with TTH or headache-free controls. Detection of accentuated VRS may therefore enhance differential diagnosis of primary headaches in children, contributing to an improvement in management.

Dry versus conventional laser imagers: film properties and image quality

The authors compared image quality and stability with a dry laser imager versus a conventional wet laser imager. Hard copies of 56 magnetic resonance imaging and computed tomographic studies were analyzed for gray-scale distribution and temperature stability. Results with the dry laser imager did not reach the quality of results with a wet laser imager, but the performance and ecologic criteria were sufficient to make use of this technique advantageous.

[Occult fractures of the wrist joint: high resolution image magnification roentgen versus MRI]

PURPOSE

To compare the diagnostic value of high definition macroradiography and MRI in patients with the suspicion of occult wrist fractures.

MATERIALS AND METHODS

In a prospective study, 23 patients with clinically suspected wrist fractures and normal initial plain radiographs underwent high resolution macroradiography and MR imaging shortly after trauma. Macroradiographs were taken with a microfocus tube using an anode of 0.03-0.3 mm providing a 4x magnification of the wrist, which was obtained in 4 projections. MR images were performed on a 1.0 T MR unit in coronal planes using T1 weighted SE, T2.-weighted 3D GE, and Turbo-STIR sequences. Follow-up radiographs after 6 weeks were used to confirm the diagnosis of a primary occult wrist fracture.

RESULTS

Macroradiography depicted 5 wrist fractures: 4 fractures of the scaphoid bone and 1 fracture of the capitate bone. MRI demonstrated 11 fractures (one of them false-positive): 9 fractures of the scaphoid bone and two fractures of the capitate bone. Using macroradiography, the sensitivity for the detection of occult fractures of the wrist was 50% with a specificity of 100%, using MRI the sensitivity was 100% with a specificity of 92%.

CONCLUSION

MRI seems to be superior to high resolution macroradiography in the detection of occult scaphoid fractures and thus is recommended in the management of patients with clinically suspected scaphoid fractures not evident on initial plain films.

[MRI arthrography of the ankle joint]

Due to its superior soft tissue contrast conventional MRI is the imaging method of choice in the evaluation of ankle joint disorders. Conventional MR imaging can accurately demonstrate normal or acutely injured ligaments; however, in subacute and chronic injury joint fluid necessary for delineation of injured ligaments is absent and MR arthrography should be performed. MR arthrography uses the intraarticular injection of contrast material to distend the joint, yielding improved discrimination of intraarticular structures. This joint distension with MR arthrography is also helpful in the staging of osteochondritis dissecans, since in cases of unstable lesions tracking of contrast material into the interface can be more easily demonstrated. Finally, high contrast and joint distension by MR arthrography improves the detection of intraarticular loose bodies, which often require surgery. MR arthrography, although invasive, may provide additional information in various ankle joint disorders.

Differentiation of benign and malignant tumors of the parotid gland: value of pulsed Doppler and color Doppler sonography

To establish criteria for the differentiation of benign and malignant tumors of the parotid gland using color Doppler sonography (CDS) and pulsed Doppler sonography (PDS) we examined 37 patients with parotid tumors by gray-scale ultrasound, CDS, and PDS. Tumor vascularization displayed by CDS was graded subjectively on a 4-point scale (0 = no vascularization, 3 = high vascularization). From the Doppler spectrum, the highest systolic peak flow velocity, the resistive index (RI), and the pulsatility index (PI) were calculated. There were 11 malignant and 26 benign tumors. Tumor vascularization by CDS was grade 0 or 1 in 88.5% of benign lesions, whereas it was grade 2 or 3 in 82% of malignant lesions (P < 0.0001). The highest systolic peak flow velocity was statistically significantly higher in malignant lesions than in benign lesions. Using a threshold systolic peak flow velocity of 25 cm/s, sensitivity was 72% and specificity was 88% for the detection of a malignant tumor. Evaluation of tumor vascularization by CDS and PDS cannot differentiate between benign and malignant parotid tumors with certainty. However, high vascularization and high systolic peak flow velocity in tumor vessels should raise the suspicion of malignancy, even if tumor morphology on gray-scale sonography indicates a benign lesion.

[Dental magnetic resonance tomography (dental MRI) as a method for imaging maxillo-mandibular tooth retention structures]

PURPOSE

To establish a new method for dental imaging using magnetic resonance tomography named Dental-MRT and to demonstrate its usefulness in diagnosing dentogen pathologies of the mandible and maxilla.

METHODS

Seven healthy volunteers, three patients with pulpitis, two patients with dentigerous cysts, two patients after tooth transplantation, and three patients with atrophic mandibles have been evaluated. Optimized axial T1- and T2-weighted gradient echo and spin echo sequences in 2D and 3D technique have been established to perform studies of the jaws. The acquired images were reconstructed with a standard dental software package on a work-station as panorama and cross-sectional views of the mandible or maxilla.

RESULTS

The entire maxillo-mandibular bone, teeth, dental pulp, and the content of the mandibular canal were well depicted. Patients with pulpitis demonstrate bone marrow edema in the periapical region. Dentigerous cysts and their relation to the surrounding structures are clearly shown. After contrast media administration marked enhancement of the dental pulp can be demonstrated.

CONCLUSION

Dental-MRT promises to provide a new tool for visualization and detection of dental diseases.

Coaxial technique: approach to breast core biopsies

PURPOSE

To assess the feasibility of the coaxial core breast biopsy technique performed under stereotactic and ultrasound (US) guidance in vitro and in vivo.

MATERIALS AND METHODS

Biopsies were performed in vitro and in vivo with a coaxial technique. In vitro, the true needle-tip deviation was measured with a breast phantom on a stereotactic device with alteration of x and y axes. In vitro US studies were performed to evaluate the optimal technique for harvesting sufficient material for histologic work-up. In 205 patients, coaxial biopsy was performed in 210 suspicious lesions under US (61 lesions) or stereotactic (patient in the sitting position, n = 67; patient in the prone position, n = 82) guidance. In addition, the coaxial system was used for preoperative localization. Surgery and histologic work-up were performed in all cases.

RESULTS

In vitro, the true needle-tip deviation was found to be less than indicated on the stereotactic device. A factor was introduced to correct this error. For US guidance, angulation or rotation of the coaxial needle within the lesion proved to be the best technique to increase the size of histologic specimen. Of the 210 lesions, 112 were benign and 98 were malignant. Agreement between biopsy results and final postsurgical histologic analysis was found in 205 cases (98%).

CONCLUSION

The coaxial breast biopsy technique is an accurate, simple, and time-saving method performed under stereotactic or US guidance.

Randomized comparison of sitting and prone positions for stereotactic fine-needle aspiration breast biopsy

In a prospective randomized study, 103 women had stereotactic biopsies performed either in the prone (n = 51) or sitting (n = 52) position. Questionnaires were administered before and after biopsy, to measure anxiety, pain and subjective experience in all patients. Vasovagal reactions were scored from 0 to 2 according to severity. There was no significant difference between biopsies performed in the sitting or the prone position with regard to overall tolerance. Significantly more patients biopsied in the prone position (15 of 51, 29 per cent) than in the sitting position (seven of 52, 13 per cent) would prefer premedication before a repeat biopsy (P = 0.04). Of the total patient group, three women fainted, one in the prone position and two others in the sitting position. Breast biopsies performed in the prone or sitting position are equally well tolerated. Somatic reactions such as fainting are not a major problem during breast biopsy; however, attention should be focused on patient care, including information given before the procedure.

[MR-pool: the "Vienna blend". An interactive computer-assisted teaching system for MRI]

Advances in the field of computer technology have facilitated the development of computer-assisted instruction. In this paper we present an interactive computer-based MR teaching system for education in radiology. Our program contains 120 teaching files. Various MR sequences can be displayed and compared to conventional X-ray images, CT, angiography and scintigraphy. Using a text field, additional clinical and diagnostic hints are offered. This teaching file can be easily upgraded and distributed on CD-ROM. Furthermore, we compare computer-assisted teaching in general to other conventional instruction media.

Recurrent suppurative thyroiditis due to pyriform sinus fistula: a case report

Acute suppurative thyroiditis is a rare disease, particularly in childhood. We present a case with recurrent acute suppurative thyroiditis due to a pyriform sinus fistula originating from the fourth branchial pouch. The typical symptoms of a pyriform sinus fistula are recurrent left-sided pain and swelling of the neck with signs of acute bacterial inflammation. Diagnosis should be made by high resolution ultrasound, barium meal studies and endoscopic examination. During acute exacerbations treatment with antibiotics is indicated, but permanent cure can only be attained by complete fistulectomy.

[Pseudolesions in liver sonography]

Several common hepatic ultrasound pseudolesions are presented that may closely resemble pathological conditions. The majority of these pitfalls is caused by normal anatomic structures, anatomical variants of the liver or the perihepatic regions, and benign alterations of the echotexture of the liver. Exact knowledge and a precise scanning technique by an experienced sonographer are essential to avoid mistaking such findings for true liver disease. In some instances (especially when dealing with anatomical variants) computed tomography is also helpful.

Errors in the center and angle of rotation of a joint: an experimental study

The error sensitivity in the determination of center and angle of rotations of a body joint performing planar motion is studied. A simple experiment is described to measure the errors in these two kinematic parameters as functions of errors in the input coordinates of markers. The effect of varying the marker locations and the size of motion-step is also studied. The errors in the center of rotation are found to increase dramatically when the two markers subtend angles of about 0 deg or 180 deg and when the motion step size decreases to 1 deg or less. Similar results are found for errors in the angle of rotation which, in addition, increase with decrease in the radius of the markers.