An extensin-rich matrix lines the carinal canals in Equisetum ramosissimum, which may function as water-conducting channels.

BACKGROUND AND AIMS: The anatomy of Equisetum stems is characterized by the occurrence of vallecular and carinal canals. Previous studies on the carinal canals in several Equisetum species suggest that they convey water from one node to another. METHODS: Cell wall composition and ultrastructure have been studied using immunocytochemistry and electron microscopy, respectively. Serial sectioning and X-ray computed tomography were employed to examine the internode-node-internode transition of Equisetum ramosissimum. KEY RESULTS: The distribution of the LM1 and JIM20 extensin epitopes is restricted to the lining of carinal canals. The monoclonal antibodies JIM5 and LM19 directed against homogalacturonan with a low degree of methyl esterification and the CBM3a probe recognizing crystalline cellulose also bound to this lining. The xyloglucan epitopes recognized by LM15 and CCRC-M1 were only detected in this lining after pectate lyase treatment. The carinal canals, connecting consecutive rings of nodal xylem, are formed by the disruption and dissolution of protoxylem elements during elongation of the internodes. Their inner surface appears smooth compared with that of vallecular canals. CONCLUSIONS: The carinal canals in E. ramosissimum have a distinctive lining containing pectic homogalacturonan, cellulose, xyloglucan and extensin. These canals might function as water-conducting channels which would be especially important during the elongation of the internodes when protoxylem is disrupted and the metaxylem is not yet differentiated. How the molecularly distinct lining relates to the proposed water-conducting function of the carinal canals requires further study. Efforts to elucidate the spatial and temporal distribution of cell wall polymers in a taxonomically broad range of plants will probably provide more insight into the structural-functional relationships of individual cell wall components or of specific configurations of cell wall polymers.

Non-lignified helical cell wall thickenings in root cortical cells of Aspleniaceae (Polypodiales): histology and taxonomical significance.

BACKGROUND AND AIMS: Extraxylary helical cell wall thickenings in vascular plants are not well documented, except for those in orchid velamen tissues which have been studied extensively. Reports on their occurrence in ferns exist, but detailed information is missing. The aim of this study is to focus on the broad patterns of structure and composition and to study the taxonomic occurrence of helical cell wall thickenings in the fern family Aspleniaceae. METHODS: Structural and compositional aspects of roots have been examined by means of light, electron, epifluorescence and laser scanning confocal microscopy. To assess the taxonomical distribution of helical cell wall thickenings a molecular phylogenetic analysis based on rbcL sequences of 64 taxa was performed. KEY RESULTS: The helical cell wall thickenings of all examined species showed considerable uniformity of design. The pattern consists of helical, regularly bifurcating and anastomosing strands. Compositionally, the cell wall thickenings were found to be rich in homogalacturonan, cellulose, mannan and xyloglucan. Thioacidolysis confirmed our negative phloroglucinol staining tests, demonstrating the absence of lignins in the root cortex. All taxa with helical cell wall thickenings formed a monophyletic group supported by a 100 % bootstrap value and composed of mainly epiphytic species. CONCLUSIONS: This is the first report of non-lignified pectin-rich secondary cell walls in ferns. Based on our molecular analysis, we reject the hypothesis of parallel evolution of helical cell wall thickenings in Aspleniaceae. Helical cell wall thickenings can mechanically stabilize the cortex tissue, allowing maximal uptake of water and nutrients during rainfall events. In addition, it can also act as a boundary layer increasing the diffusive pathway towards the atmosphere, preventing desiccation of the stele of epiphytic growing species.

Smokers' unrealistic optimism about their risk.

OBJECTIVE: Past studies have produced ambiguous or inconsistent results when testing whether smokers actually underestimate their own risks of experiencing tobacco related illness. Whereas smokers claim that they are less at risk than the average smoker on self administered questionnaires, this unrealistic optimism has not been found in telephone or face-to-face interviews. We avoided the measurement problems of past studies and examined responses to a number of new questions to assess different aspects of smokers' perceptions. METHODOLOGY: A US national telephone survey (n = 6369; 1245 current smokers) posed a variety of questions designed to examine beliefs about the risks of smoking. For key questions, separate samples of smokers were asked either about their own risk or about the risk of the average smoker. RESULTS: Smokers underestimated their relative risk compared to non-smokers and, contrary to previous interview surveys, believed they have a lower risk of developing lung cancer than the average smoker. Furthermore, their perceived risk of lung cancer and of cancer in general barely increases with the number of cigarettes smoked per day, and their estimates of their risk of cancer are actually slightly lower than their estimates of their risk of lung cancer. Substantial proportions of smokers and former smokers agree with several myths, more than half agreeing that exercise undoes most smoking effects. CONCLUSION: Smokers underestimate their risk of lung cancer both relative to other smokers and to non-smokers and demonstrate other misunderstandings of smoking risks. Smoking cannot be interpreted as a choice made in the presence of full information about the potential harm.

Modulation of the degree and pattern of methyl-esterification of pectic homogalacturonan in plant cell walls. Implications for pectin methyl esterase action, matrix properties, and cell adhesion.

Homogalacturonan (HG) is a multifunctional pectic polysaccharide of the primary cell wall matrix of all land plants. HG is thought to be deposited in cell walls in a highly methyl-esterified form but can be subsequently de-esterified by wall-based pectin methyl esterases (PMEs) that have the capacity to remove methyl ester groups from HG. Plant PMEs typically occur in multigene families/isoforms, but the precise details of the functions of PMEs are far from clear. Most are thought to act in a processive or blockwise fashion resulting in domains of contiguous de-esterified galacturonic acid residues. Such de-esterified blocks of HG can be cross-linked by calcium resulting in gel formation and can contribute to intercellular adhesion. We demonstrate that, in addition to blockwise de-esterification, HG with a non-blockwise distribution of methyl esters is also an abundant feature of HG in primary plant cell walls. A partially methyl-esterified epitope of HG that is generated in greatest abundance by non-blockwise de-esterification is spatially regulated within the cell wall matrix and occurs at points of cell separation at intercellular spaces in parenchymatous tissues of pea and other angiosperms. Analysis of the properties of calcium-mediated gels formed from pectins containing HG domains with differing degrees and patterns of methyl-esterification indicated that HG with a non-blockwise pattern of methyl ester group distribution is likely to contribute distinct mechanical and porosity properties to the cell wall matrix. These findings have important implications for our understanding of both the action of pectin methyl esterases on matrix properties and mechanisms of intercellular adhesion and its loss in plants.

Analysis of the distribution of copper amine oxidase in cell walls of legume seedlings.

Copper-containing amine oxidase (CuAO) has been proposed to play a role in H2O2 production in plant cell walls during cell development and in response to pathogen attack. We have compared the localisation of CuAO in pea (Pisum sativum L.), lentil (Lens culinaris M.) and chick pea (Cicer arietinum L.) grown under different light conditions, using both immuno- and histochemical techniques. The enzyme was detected by indirect immunofluorescence in the cell walls of parenchyma tissues of etiolated pea and lentil plants and was particularly abundant at intercellular spaces. Upon de-etiolation, CuAO largely disappeared from cortical cell walls except in the region of intercellular spaces. In the apical internode of light-grown seedlings, CuAO occurred mainly in cortical cell walls and, to some extent, in cell walls of xylem vessels. In both the elongation zone and mature regions of roots, CuAO was restricted to cortical cell walls and some cell junctions close to the meristem. Extensin epitopes co-localised to intercellular spaces of the cortex in de-etiolated pea, indicating that CuAO may have a role in cell wall strengthening at intercellular spaces. In chick pea, the localisation of the enzyme varied between different cultivars that have differing susceptibility to the fungus Ascochyta rabiei. In a susceptible cultivar Calia, immunogold labelling localised CuAO to cell walls of the cortex, as in lentil and pea, while in a resistant cultivar Sultano, it was most abundant in xylem vessels and, in light-grown plants, in the epidermis. These expression patterns are discussed with regard to the possible functions of amine oxidase in cell growth, cell differentiation and pathogen resistance.

Interaction between the serotonin transporter gene and neuroticism in cigarette smoking behavior.

Cigarette smoking behavior is influenced by both personality traits and inherited factors. Previous research showed that neuroticism-a broad personality domain that includes anxiety, depression, impulsiveness and vulnerability-increases the risk of being a smoker, primarily because of difficulty in quitting. Neuroticism has also been associated with the 5-HTTLPR, a functional polymorphism in the promoter for the serotonin transporter gene. We used population and family-based methods to analyze the joint effects of the 5-HTTLPR and neuroticism on smoking behavior in a population of 759 never, current, and former smokers, all members of sib-pairs. Our main finding is that smoking behavior is influenced by an interaction between neuroticism and 5-HTTLPR genotype. Specifically, neuroticism was positively correlated with current smoking and negatively associated with smoking cessation in individuals and siblings with poorly transcribed 5-HTTLPR-S genotypes, but not in those with the more highly expressed 5-HTTLPR-L genotype. Individuals with both a 5-HTTLPR-S genotype and a high level of neuroticism had the greatest difficulty in quitting smoking. These data, if replicated, suggest that smoking behavior is more strongly influenced by the combination of the serotonin transporter gene and neuroticism than by either factor alone, and that personality scores and 5-HTTLPR genotype may predict the clinical efficacy of certain smoking cessation drugs.

Sociodemographic correlates of tooth pain among adults: United states, 1989.

This study presents the sociodemographic distribution of tooth pain and the dental care utilization of affected individuals. Data for adults 20 years of age and over were derived from the 1989 National Health Interview Survey's supplements on dental health, orofacial pain, and health insurance (n=33073). Prevalence of tooth pain by socioeconomic status (SES) and adjusted odds ratios of reporting tooth pain in the past 6 months and of having no dental visits in the past year among persons reporting pain in the previous 6 months were computed taking into account the survey's complex sample design. Tooth pain in the past 6 months was reported by 14.5% (95% CI 14.0, 15.0) of adults aged 20-64 years and by 7.0% (95% CI 6.1, 7.9) of those 65 years and over. In the younger age group, tooth pain was more likely to be reported by those with low SES than it was by those with high SES; in the older age group, tooth pain was more likely reported by non-Hispanic blacks than it was by non-Hispanic whites or Hispanics. Of those reporting pain, younger and older non-Hispanic blacks and persons with lower educational attainment were more likely not to have a dental visit in the previous 12 months. Persons with low SES characteristics were more likely to report tooth pain and to endure their pain without the benefit of dental care while the pain was present.

Environmental covariates: effects on the power of sib-pair linkage methods.

The effect of inclusion of environmental risk factors on the power of sib-pair linkage methods was tested for a qualitative trait. It was found that inclusion of an environmental variable did not increase the power of the Haseman-Elston (H-E) sib-pair nonparametric linkage analysis test. However, a significant increase in power was observed for both the H-E and affected-sib-pair tests, even in small samples, when persons unexposed to the environmental risk factor were coded as unknown.

A genetic association for cigarette smoking behavior.

Dopaminergic genes are likely candidates for heritable influences on cigarette smoking. In an accompanying article, Lerman et al. (1999) report associations between allele 9 of a dopamine transporter gene polymorphism (SLC6A3-9) and lack of smoking, late initiation of smoking, and length of quitting attempts. The present investigation extended their study by examining both smoking behavior and personality traits in a diverse population of nonsmokers, current smokers, and former smokers (N = 1,107). A significant association between SLC6A3-9 and smoking status was confirmed and was due to an effect on cessation rather than initiation. The SLC6A3-9 polymorphism was also associated with low scores for novelty seeking, which was the most significant personality correlate of smoking cessation. It is hypothesized that individuals carrying the SLC6A3-9 polymorphism have altered dopamine transmission, which reduces their need for novelty and reward by external stimuli, including cigarettes.

Generation of monoclonal antibody specific to (1-->5)-alpha-L-arabinan.

A neoglycoprotein (a heptasaccharide of (1-->5)-alpha-L-linked-arabinosyl residues linked to bovine serum albumin) has been used to generate a rat monoclonal antibody specific to a linear chain of (1-->5)-alpha-L-arabinan which is a structural feature of the side chains of pectins. The antibody, designated LM6, detected 100 ng of debranched sugar beet arabinan in an immunodot binding assay and 1 microgram of commercial citrus pectin in a similar assay. Hapten inhibition studies indicated that the antibody recognized 5-6 Ara residues and 50% inhibition of antibody binding in a competitive inhibition ELISA was achieved with ca. 2ng (21 nM) of (1-->5)-alpha-L-Arabinohexaose. The antibody will be useful for the localization of arabinans in plant tissue and will have uses in the analyses of pectin structure. We report here on the localization of the arabinan epitope in lemon fruits using tissue printing.

Tooth retention and tooth loss in the permanent dentition of adults: United States, 1988-1991.

While the overall prevalence of tooth loss and edentulism has been declining in the United States over the past several decades, important variations remain among subgroups of the population. Data from Phase 1 of the Third National Health and Nutrition Examination Survey (NHANES III) provide the most current estimates of the prevalence and distribution of tooth retention and tooth loss in the United States. Weighted analyses were conducted for all adults 18+ years of age (n=8,366) and for selected age, gender, and race-ethnicity groups. In 1988-91, 89.5% of the population was dentate, and 30.5% had retained all 28 teeth. The mean number of teeth retained was 21.1 for all adults and 23.5 for dentate persons. The most commonly retained teeth in the mouth were the six anterior teeth in the lower arch. Conversely, 10.5% of the population was edentulous. Partial edentulism was much more common in the upper arch than in the lower arch. The most commonly missing teeth were the first and second molars. Age was strongly related to every measure of tooth retention and tooth loss. Gender was not related to any of these measures, after adjustment for age. Race-ethnicity was consistently related to these measures, after adjustment for age and gender. In general, Mexican-Americans had the lowest and black non-Hispanics the highest rates of tooth loss. Future research needs to examine a wide range of potential correlates of tooth retention and tooth loss before we can understand the complex interplay among the personal, dental, and environmental factors influencing tooth retention and tooth loss in the United States.

Evaluation of the 1990 Centers for Disease Control and Prevention smoke-free policy.

PURPOSE: To determine the prevalence of tobacco use among Centers for Disease Control and Prevention (CDC)/Agency for Toxic Substances and Disease Registry (ATSDR) employees and the effect of the smoke-free policy on smoking behavior and air quality at work. DESIGN: A stratified telephone survey of 1181 CDC/ATSDR employees randomly selected from employee rosters. SETTING: CDC/ATSDR work sites in Atlanta, Georgia, and other major CDC locations throughout the United States and Puerto Rico. SUBJECTS: Randomly selected employees of CDC/ATSDR1, or about 22% of the total CDC/ATSDR population; 98% of eligible persons selected agreed to participate. MEASURES: Demographic and smoking history variables, attitudes toward and impact of the smoke-free policy on smoking behavior, and self-report changes in air quality were the measures used. RESULTS: Overall cigarette smoking prevalence was only 11.1%. One percent reported using chewing tobacco, 1.1% reported smoking a pipe, and 1.4% reported smoking cigars. Average self-reported, daily cigarette consumption significantly decreased after the smoking ban took effect. Overall, 90% of the employees supported the smoke-free policy, and 80% of the employees believed that smokers were complying with the smoke-free policy. Most employees believed that the air quality of work areas and nonwork areas (65% and 69%, respectively) had improved since the smoke-free policy was implemented. CONCLUSIONS: These findings are consistent with previous evaluations of smoke-free policies and suggest that most employees are generally supportive of workplace smoking restrictions. Such policies can also have a positive impact on smoking behavior and perceived air quality.

Prevalence and demographic correlates of tooth loss among the elderly in the United States.

The aging of the United States population and the contribution of tooth loss to oral health make it important to describe tooth loss among the elderly in this country. Data from the National Survey of Oral Health in US Employed Adults and Seniors: 1985-1986, conducted by the National Institute of Dental Research, were analyzed to examine the prevalence and demographic correlates of tooth loss among the elderly. Results show that there were important differences in tooth loss among subgroups of the elderly sample (overall n = 5,649 persons aged 65+ years attending senior centers). The oldest seniors and those with the least education or income were the most likely to be edentulous. The oldest dentulous seniors, blacks, those with the least education or income, and those who lived in New England or the Northeast had the fewest number of teeth present. These findings suggest that efforts to reduce tooth loss among the elderly should target those with the least education and income.

Public attitudes about cigarette smoking: results from the 1990 Smoking Activity Volunteer Executed Survey.

The 1990 Smoking Activity Volunteer Executed Survey collected information on a wide range of policy-relevant issues concerning public attitudes about cigarette smoking. These issues include cigarette taxes, advertising restrictions, minors' access to tobacco products, school-based prevention, and exposure to environmental tobacco smoke in workplaces and public areas. Survey data were collected during the spring and summer months of 1990 from random samples of adults from Arizona, Michigan, Pennsylvania, and Texas. Telephone interviews were conducted by trained American Cancer Society volunteers using standardized questionnaires. Cluster sampling techniques, interviewer training and supervision, and data collection procedures were designed in conformity with the methodology of the Behavioral Risk Factor Surveillance System of the Centers for Disease Control and Prevention. Smoking prevalence ranged from a low of approximately 20 percent in Texas to a high of 31 percent in Michigan. Between 60 and 69 percent of the respondents in the four States, including between 44 and 71 percent of current smokers, believe tobacco should be classified as a drug. Around 65 percent of the respondents would support an extra tax on tobacco to finance public campaigns against smoking, and between 61 percent and 69 percent favor banning cigarette advertising in the print media and on billboards. More than 82 percent of the respondents believe that stronger laws should be enacted to prevent the sale of tobacco products to minors, and more than 86 percent believe that existing laws should be better enforced. Current smokers were only slightly less likely than were former and never smokers to indicate support of policy changes to prevent minors'access to tobacco products; the two groups had somewhat more disagreement in the amount of support for the other smoking control policies.Finally, although between 62 and 88 percent of working respondents reported the presence of smoking restrictions at their workplace, between 26 and 48 percent still reported being bothered by smoking at work.These study findings suggest that existing smoking control policies are not restrictive enough or are inadequately enforced. The study documents strong public concern in the four States about the in adequacy of current policies and support for the enactment of stronger legislation to control smoking behavior.

Sports participation, age at smoking initiation, and the risk of smoking among US high school students.

OBJECTIVE: To examine smoking patterns, smoking initiation, and the relationship of sports participation and age at smoking initiation to regular and heavy smoking among adolescents. DESIGN: Survey. PARTICIPANTS: A nationally representative sample of US high school students. OUTCOME MEASURES: Prevalences of smoking patterns, prevalence and incidence of smoking initiation, and prevalences and odds of regular and heavy smoking in relation to sports participation and age at smoking initiation. RESULTS: Seventy-two percent of students reported experimenting with, formerly, or ever smoking cigarettes, and 32% reported smoking in the past 30 days. Students who had participated in interscholastic sports were less likely to be regular and heavy smokers than were others who had not participated. Smoking initiation rates increased rapidly after age 10 years and peaked at age 13 to 14 years. Students who began smoking at age 12 years or younger were more likely to be regular and heavy smokers than were students who began smoking at older ages. CONCLUSIONS: These data suggest that smoking initiation at a young age can increase the risk of nicotine addiction during adolescence and that sports participation may influence smoking behavior. Interventions to prevent smoking should be available before age 12 years to help combat the smoking epidemic among youth.

Do objective estimates of chances for survival influence decisions to withhold or withdraw treatment? The French Multicentric Group of ICU Research.

The authors studied the impact on clinical decision making of providing feedback of objective prognostic information describing the probability of survival for ICU patients with multiple organ system failure (OSF). The prognostic estimates, derived from a control period (1), were to be provided on a daily basis to physicians providing treatment in 25 French ICUs during a subsequent experimental period (2). The types of, frequencies of, and reasons for decisions to limit or stop treatment in the two periods were compared. In the experimental period 2, 17 ICUs participated in the feedback study. Within these 17 units, there was a small but significant (p less than 0.05) increase in decisions to stop active treatment and provide comfort care that was limited to patients with three or more OSFs. There was no change in decision making in the eight units that did not participate in the feedback study. Although these results suggest a direct causal relationship between the provision of objective prognostic data and changes in physician decision making, the small increase in comfort care decisions (n = 14) between period 1 and period 2 and the fact that only 17 of the 25 original units participated in the feedback study make it difficult to eliminate other influences. There was no indication in this study, however, that explicit provision of prognostic data led to a sense of therapeutic futility.

Statistical methods in SUPPORT.

The analysis and interpretation of the data collected in SUPPORT provide great potential for understanding the relationships among treatment choices, patient and physician values and preferences, perceptions about the risks and benefits of treatments, institutional characteristics, and outcomes (as measured by quality of life, survival, and satisfaction). The complicated analyses required to elucidate these relationships will pose many technical challenges in dealing with longitudinal observational data collected from seriously ill patients at multiple sites. Major challenges include the handling of incomplete data, proper parameterization of treatment effects, strategies to avoid various potential biases, validating predictive models, and constructing endpoints that combine survival with quality of life. Within the structure of the SUPPORT study, mechanisms have been established to guide the analyses and to ensure their quality and validity.

Factors associated with the use of psychiatric consultations in short-term general hospitals.

A significant number of patients in general hospitals suffer from psychiatric distress or illness, but not all receive psychiatric consultation. This study examined several potential predictors of such consultation. These included patient characteristics (age, sex, race, insurance, disease stage, and number of medical diagnoses), characteristics of hospital stay (number of procedures, other consultations, length of stay, discharge destination), hospital characteristics (size, percent occupancy, teaching status, presence of a psychiatric unit, type of control), and community characteristics (region, urban/rural setting). Data were derived from a national sample of 327 hospitals. Parallel analyses using stepwise logistic regression were carried out across four samples: patients determined at discharge to have been hospitalized for diabetes, hip fracture, chronic obstructive pulmonary disease, and coronary artery bypass surgery. Results show a wide variation in the use of psychiatric consultations across different subgroups. Longer lengths of stay, urban setting. Northeast region, younger patient age, and other consultations were the most consistent predictors of the probability of psychiatric consultation. These variations may reflect differences in the need for consultation, differential recognition of these needs by providers, or differential availability of psychiatric consultation services. Moreover, they may have implications for equity and/or quality of hospital care.

Psychiatric consultations in short-term general hospitals.

We investigated the use of psychiatric consultations in short-term general hospitals using a national sample of 327 hospitals and examining the hospital experience of approximately 263,000 patients discharged from these hospitals. We found that the demographic characteristics of patients receiving psychiatric consultations in the national sample were roughly similar to those reported for patients receiving consultations in earlier, single-hospital studies. Rates of consultation were considerably lower, however: 0.9%, compared with a median rate of 3.3% reported in the literature. We also found that patients receiving psychiatric consultations used more hospital resources than other patients.