bluuebunny/crossref_metadata_2025 huggingface dataset:
Mortality and cancer incidence of Australian participants in the British nuclear tests in Australia
Authors: Gun R T , Parsons J , Crouch P , Ryan P , Hiller J E
Published: September 2008

Objectives:

To investigate the mortality and cancer incidence of Australian nuclear test participants, and to identify any association with exposure to ionising radiation.

Methods:

A retrospective cohort study was carried out in which the mortality and cancer incidence rates of participants (n = 10 983) were compared with rates in the general male Australian population. Dose reconstructions were carried out by a panel of health physicists. Mortality and cancer rates were compared with the general population and between groups of subjects categorised by assessed radiation exposure.

Results:

All-cause mortality was not raised. Mortality and incidence were significantly raised for cancers of the head and neck, lung, colon and rectum, and prostate, and for all cancers combined. For oesophageal cancer, melanoma, all leukaemias and non-chronic lymphatic leukaemia (non-CLL leukaemia), incidence was significantly raised, but mortality was non-significantly raised. No association was found between radiation exposure and overall cancer incidence or mortality, or with any cancer or cancer deaths occurring in excess.

Conclusions:

There is no evidence that the excess cancers and cancer deaths were caused by radiation exposure at the test sites. Possible contributing factors are high smoking prevalence and demographic differences from the Australian population with whom rates were compared. Asbestos is a likely contributor to some cancers in naval personnel.
Occupation/industry and risk of non-Hodgkin’s lymphoma in the United States
Authors: Schenk M , Purdue M P , Colt J S , Hartge P , Blair A , Stewart P , Cerhan J R , De Roos A J , Cozen W , Severson R K
Published: September 2008

Aims:

To identify occupations and industries associated with non-Hodgkin’s lymphoma (NHL) in a large population-based, case-control study in the USA.

Methods:

Cases (n = 1189) of histologically confirmed malignant NHL ages 20–74 were prospectively identified in four geographic areas covered by the National Cancer Institute SEER Program. Controls (n = 982) were selected from the general population by random digit dialling (<65 years of age) and from residents listed in Medicare files (65–74 years of age). Odds ratios and 95% confidence intervals for occupations and industries were calculated by unconditional logistic regression analyses, adjusting for age, gender, ethnicity and study centre. Further analyses stratified for gender and histological subtype were also performed.

Results:

Risk of NHL was increased for a few occupations and industries. Several white collar occupations, with no obvious hazardous exposures, had elevated risks, including purchasing agents and buyers, religious workers, physical therapists and information clerks. Occupations with excesses that may have exposures of interest include launderers and ironers, service occupations, food/beverage preparation supervisors, hand packers and packagers, roofing and siding, leather and leather products, transportation by air, nursing and personal care facilities, and specialty outpatient clinics. Significantly decreased risks of NHL were found for a number of occupations and industries including post-secondary teachers and chemical and allied products.

Conclusions:

The results of this study suggest that several occupations and industries may alter the risk of NHL. Our results support previously reported increased risks among farmers, printers, medical professionals, electronic workers and leather workers. These findings should be evaluated further in larger studies that have the power to focus on specific exposures and histological subtypes of NHL.
Work pattern causes bias in self-reported activity duration: a randomised study of mechanisms and implications for exposure assessment and epidemiology
Authors: Barrero L H , Katz J N , Perry M J , Krishnan R , Ware J H , Dennerlein J T
Published: September 2008

Background:

Self-reported activity duration is used to estimate cumulative exposures in epidemiological research.

Objective:

The effects of work pattern, self-reported task dullness (a measure of cognitive task demand), and heart rate ratio and perceived physical exertion (measures of physical task demands) on error in task duration estimation were investigated.

Methods:

24 participants (23–54 years old, 12 males) were randomly assigned to execute three tasks in either a continuous (three periods of 40 continuous minutes, one for each task) or a discontinuous work pattern (40 min tasks each divided into four periods of 4, 8, 12 and 16 min). Heart rate was measured during tasks. After completing the 2 h work session, subjects reported the perceived duration, dullness and physical exertion for each of the three tasks. Multivariate models were fitted to analyse errors and their absolute value to assess the accuracy in task duration estimation and the mediating role of task demands on the observed results.

Results:

Participants overestimated the time spent shelving boxes (up to 38%) and filing journals (up to 9%), and underestimated the time typing articles (up to −22%). Over- and underestimates and absolute errors were greater in the discontinuous work pattern group. Only the self-reported task dullness mediated the differences in task duration estimation accuracy between work patterns.

Conclusions:

Task-related factors can affect self-reported activity duration. Exposure assessment strategies requiring workers to allocate work time to different tasks could result in biased measures of association depending on the demands of the tasks during which the exposure of interest occurs.
Future needs of occupational epidemiology of extremely low frequency electric and magnetic fields: review and recommendations
Authors: Kheifets L , Bowman J D , Checkoway H , Feychting M , Harrington J M , Kavet R , Marsh G , Mezei G , Renew D C , van Wijngaarden E
Published: September 2008

The occupational epidemiological literature on extremely low frequency electric and magnetic fields (EMF) and health encompasses a large number of studies of varying design and quality that have addressed many health outcomes, including various cancers, cardiovascular disease, depression and suicide, and neurodegenerative diseases, such as Alzheimer disease and amyotrophic lateral sclerosis (ALS). At a 2006 workshop we reviewed studies of occupational EMF exposure with an emphasis on methodological weaknesses, and proposed analytical ways to address some of these. We also developed research priorities that we hope will address remaining uncertainties. Broadly speaking, extensive epidemiological research conducted during the past 20 years on occupational EMF exposure does not indicate strong or consistent associations with cancer or any other health outcomes. Inconsistent results for many of the outcomes may be attributable to numerous shortcomings in the studies, most notably in exposure assessment. There is, however, no obvious correlation between exposure assessment quality and observed associations. Nevertheless, for future research, the highest priorities emerge in both the areas of exposure assessment and investigation of ALS. To better assess exposure, we call for the development of a more complete job-exposure matrix that combines job title, work environment and task, and an index of exposure to electric fields, magnetic fields, spark discharge, contact current, and other chemical and physical agents. For ALS, we propose an international collaborative study capable of illuminating a reported association with electrical occupations by disentangling the potential roles of electric shocks, magnetic fields and bias. Such a study will potentially lead to evidence-based measures to protect public health.
Does return to work occur earlier after work-related sick leave episodes than after non-work-related sick leave episodes? A retrospective cohort study in Spain
Authors: Benavides F G , Serra C , Domínguez R , Martínez J M , Plana M , Despuig M , Sampere M , Gimeno D
Published: September 2008

Objective:

In Spain, sick pay benefits for work-related sick leave episodes are higher than for non-work-related episodes. Our aim is to assess whether time to return to work is longer for higher paid sick leave episodes than for lower paid episodes.

Methods:

We used data from 62 376 work-related and 76 932 non-work-related sick leave episodes occurring among 338 226 workers from 56 099 companies in Spain in 2002. All episodes were followed for up to 18 months. Episodes were classified by a physician as being work- or non-work-related according to medico-legal judgments. The median episode duration and the 25th and 75th percentiles were calculated. The probability of remaining absent from work was estimated by a non-parametric estimator of the marginal survival function. The time ratio between both types of sick leave was estimated by a log-logistic regression model, using non-work-related episodes as the reference.

Results:

Median episode duration (25th–75th percentiles) was 11 (6–21) days for work-related episodes and 9 (4–29) days for non-work-related episodes. Time to return to work was longer for work-related episodes than for non-work-related episodes of less than 16 days (time ratio: 1.19 in men and 1.08 in women), while the opposite was observed for episodes of more than 15 days (0.58 in men and 0.40 in women).

Conclusions:

Sick pay benefits have a limited effect on time to return to work after a sick leave episode.
Lung cancer mortality and iron oxide exposure in a French steel-producing factory
Authors: Bourgkard E , Wild P , Courcot B , Diss M , Ettlinger J , Goutet P , Hémon D , Marquis N , Mur J-M , Rigal C , Rohn-Janssens M-P , Moulin J-J
Published: September 2008

Objective:

To study the possible association between iron oxide exposures and lung cancer risk among workers in a French carbon steel-producing factory.

Methods:

16 742 males and 959 females ever employed for at least 1 year between 1959 and 1997 were followed up for mortality from January 1968 to December 1998. Causes of death were ascertained from death certificates. Job histories and smoking habits were available for 99.7% and 72.3% of subjects, respectively. Occupational exposures were assessed by a factory-specific job-exposure matrix (JEM) validated with atmospheric measurements. Standardised mortality ratios (SMRs) were computed using local death rates (external references). Poisson regressions were used to estimate the relative risks (RRs) for occupational exposures (internal references), adjusted on potential confounding factors.

Results:

Among males, observed mortality was lower than expected for lung cancer compared to the local population (233 deaths, SMR 0.89, 95% CI 0.78 to 1.01) and higher than expected compared to the French population (SMR 1.30, 95% CI 1.15 to 1.48) No lung cancer excess was observed for exposure to iron oxides (RR 0.80, 95% CI 0.55 to 1.17) and no dose–response relationship with intensity, duration of exposure or cumulative index was found. A significant bladder cancer excess was observed among workers exposed to oil mist (RR 2.44, 95% CI 1.06 to 5.60), increasing significantly with intensity, duration of exposure and cumulative index.

Conclusion:

This study did not detect any relationship between exposure to iron oxides and lung cancer mortality. An excess of mortality from bladder cancer was found among workers exposed to oil mist.
Predicted mortality from malignant mesothelioma among women exposed to blue asbestos at Wittenoom, Western Australia
Authors: Reid A , Berry G , Heyworth J , de Klerk N H , Musk A W
Published: September 2008

Introduction:

Nearly 3000 women and girls were documented to have lived at the blue asbestos mining and milling town of Wittenoom in Western Australia between 1943 and 1992. Eight per cent of deaths among these women to the end of 2004 have been from malignant mesothelioma of the pleura.

Aim:

To predict future mortality from mesothelioma to 2030 in this cohort.

Methods:

Mesothelioma mortality rates incorporating parameters for cumulative exposure, a power of time since first exposure and annual rates of fibre clearance from the lung were calculated from maximum likelihood estimates. These rates plus age specific mortality rates for Western Australian females incorporating an excess lung cancer risk were then applied to all Wittenoom cohort women surviving to the end of 2004, in yearly increments, to predict the future numbers of cases of mesothelioma to 2030.

Results:

There were 40 deaths from mesothelioma among the Wittenoom women to the end of 2004. Using a range of models that incorporate time since first exposure, competing risks from other diseases, latency periods and clearance of mesothelioma from the lungs we predict 66 (lowest estimate) to 87 (highest estimate) deaths from mesothelioma until 2030. This represents one and a half to two and a half times the number of deaths that have already occurred to the end of 2004.

Conclusion:

The high toll from mesothelioma in this cohort of women and girls will continue well into the future.
Dust and chemical exposures, and miscarriage risk among women textile workers in Shanghai, China
Authors: Wong E Y , Ray R M , Gao D-L , Wernli K J , Li W , Fitzgibbons E D , Camp J E , Astrakianakis G , Heagerty P J , De Roos A J , Holt V L , Thomas D B , Checkoway H
Published: September 2008

Introduction:

To investigate possible associations between miscarriage and occupational exposures in the Shanghai textile industry.

Methods:

A retrospective cohort study of miscarriages among 1752 women in the Shanghai textile industry was conducted. Reproductive history was self-reported by women and occupational work histories were collected from factory personnel records. Occupational exposures were assigned by linking work history information to an industry-specific job-exposure matrix informed by factory-specific textile process information and industrial hygiene assessments. Estimates of cotton dust and endotoxin exposure were also assigned. Odds ratios (OR) and 95% CI were estimated by multivariate logistic regression, with adjustment for age at pregnancy, educational level, smoking status of the woman and her spouse, use of alcohol, and woman’s year of birth.

Results:

An elevation in risk of a spontaneously aborted first pregnancy was associated with exposure to synthetic fibres (OR 1.89, 95% CI 1.20 to 3.00) and mixed synthetic and natural fibres (OR 3.31, 95% CI 1.30 to 8.42). No increased risks were observed for women working with solvents, nor were significant associations observed with quantitative cotton dust or endotoxin exposures. Associations were robust and similar when all pregnancies in a woman’s reproductive history were considered.

Conclusions:

Occupational exposure to synthetic fibres may cause miscarriages, and this possibility should be the subject of further investigation.
Cumulative exposure to high-strain and active jobs as predictors of cognitive function: the Whitehall II study
Authors: Elovainio M , Ferrie J E , Singh-Manoux A , Gimeno D , De Vogli R , Shipley M J , Vahtera J , Brunner E J , Marmot M G , Kivimäki M
Published: September 2008

Objectives:

A high-strain job (a combination of high job demands and low job control) is expected to increase the risk of health problems, whereas an active job (high demands and high control) can be hypothesised to be associated with a greater capacity to learn. We tested associations between high-strain and active jobs and cognitive function in middle-aged men and women.

Methods:

Data on 4146 British civil servants (2989 men and 1157 women) aged 35–55 years at baseline came from the Whitehall II study. Cumulative exposure to both high-strain and active jobs was assessed at phases 1 (1985–1988), 2 (1989–1990) and 3 (1991–1993). Cognitive performance was assessed at phases 5 (1997–1999) and 7 (2003–2004) using the following tests: verbal memory, inductive reasoning (Alice Heim), verbal meaning (Mill Hill), phonemic and semantic fluency. Analyses were adjusted for age, sex and employment grade.

Results:

Longer exposure to high job strain and shorter exposure to active jobs were associated with lower scores in most of the cognitive performance tests. However, these associations disappeared on adjustment for employment grade. Phonemic fluency was an exception to this pattern. Associations between exposure to an active job and phonemic fluency at both follow-up phases were robust to adjustment for employment grade. However, there was no association between exposure to active jobs and change in phonemic fluency score between the follow-up phases after adjustment for employment grade.

Conclusions:

In these data, associations between cumulative exposure to high-strain or active jobs and cognition are largely explained by socioeconomic position.
A cross-sectional study of lung function and respiratory symptoms among chemical workers producing diacetyl for food flavourings
Authors: van Rooy F G B G J , Smit L A M , Houba R , Zaat V A C , Rooyackers J M , Heederik D J J
Published: September 2008

Objectives:

Four diacetyl workers were found to have bronchiolitis obliterans syndrome. Exposures, respiratory symptoms, lung function and exposure–response relationships were investigated.

Methods:

175 workers from a plant producing diacetyl between 1960 and 2003 were investigated. Exposure data were used to model diacetyl exposure. Lung function and questionnaire data on respiratory symptoms were compared to a general population sample and respiratory symptoms to an internal reference group.

Results:

Workers were potentially exposed to acetoin, diacetyl, acetaldehyde and acetic acid. Historic diacetyl exposure ranged from 1.8 to 351 mg/m3, and from 3 to 396 mg/m3for specific tasks. Diacetyl workers reported significantly more respiratory symptoms compared to the general population sample (continuous trouble with breathing (prevalence ratio (PR) = 2.6; 95% CI 1.3 to 5.1), daily cough (PR = 1.5; 95% CI 1.1 to 2.1), asthma attack (ever) (PR = 2.0; 95% CI 1.2 to 3.4), doctor diagnosed asthma (PR = 2.2; 95% CI 1.3 to 3.8) and asthma attack in the last year (PR = 4.7; 95% CI 1.9 to 11.4)) and to a minimally exposed internal reference group (ever trouble with breathing (PR = 2.8; 95% CI 1.1 to 7.0) and work-related shortness of breath in the last year (PR = 7.5; 95% CI 1.1 to 52.9)). Lung function did not differ between groups. A positive relationship between exposure and FEV1was found.

Conclusion:

The excess of respiratory symptoms in this retrospective cohort suggests that diacetyl production poses an occupational hazard. Limited historical exposure data did not support a quantitative individual diacetyl exposure–response relationship, but our findings suggest that preventive measures are prudent.
Estimates of historical exposures by phase contrast and transmission electron microscopy in North Carolina USA asbestos textile plants
Authors: Dement J M , Myers D , Loomis D , Richardson D , Wolf S
Published: September 2008

Objectives:

To develop a job-exposure matrix (JEM) for fibre exposures in three asbestos textile plants and to develop estimates of fibre size-specific exposures.

Methods:

Historical dust samples from three North Carolina, USA asbestos textile plants were obtained. Plant specific samples were used to express impinger dust concentrations as fibre concentrations by phase contract microscopy (PCM). Mixed models were used to estimate PCM exposures by plant, department, job and calendar time. Archived membrane filter samples were analysed by transmission electron microscopy (TEM) to determine the bivariate diameter/length distribution of airborne fibres by plant and operation.

Results:

PCM fibre levels estimated from the models were very high in the 1930s, with some operations having in excess of 200 fibres/ml, and decreased appreciably over time. TEM results for 77 airborne dust samples found that only a small proportion of airborne fibres were measured by PCM (>0.25 μm in diameter and >5 μm in length) and the proportion varied considerably by plant and operation (range 2.9% to 10.0%). The bivariate diameter/length distribution of airborne fibres demonstrated a relatively high degree of variability by plant and operation. PCM adjustment factors also varied substantially across plants and operations.

Conclusions:

These data provide new information concerning airborne fibre levels and characteristics in three historically important asbestos textile plants. PCM concentrations were high in the early years and TEM data demonstrate that the vast majority of airborne fibres inhaled by the workers were shorter than 5 μm in length, and thus not included in the PCM-based fibre counts.
Use of hair colouring products and risk of multiple myeloma among US women: Table 1
Authors: Koutros S , Baris D , Bell E , Zheng T , Zhang Y , Holford T R , Leaderer B P , Landgren O , Hoar Zahm S
Published: September 2008

Objective:

To evaluate the association between personal hair dye use and risk of multiple myeloma among women.

Methods:

A population-based case–control study of 175 cases of multiple myeloma and 679 controls. Cases and controls were interviewed regarding the type and colour of hair colouring product used, age at first use, age use stopped, duration, and the frequency of use per year. Odds ratios (ORs) and 95% confidence intervals (CI) were estimated using unconditional logistic regression to compare never users with four exposure groups: all users, ever semi-permanent dye users, ever permanent dye users and dark permanent dye users (most frequent use).

Results:

No association was found between ever reporting hair colouring product use and myeloma risk among all users (OR 0.8; 95% CI 0.5 to 1.1), semi-permanent dye users (OR 0.7; 95% CI 0.4 to 1.2), permanent dye users (OR 0.8; 95% CI 0.5 to 1.1) or dark permanent dye users (OR 0.8; 95% CI 0.5 to 1.3). There were no significant associations among women who used hair dyes before 30 years of age, started use before 1980, had ⩾240 lifetime applications, or had used dark permanent dye for 28 or more years.

Conclusion:

No evidence of an association between hair colouring product use and myeloma risk was found. However, given the conflicting body of literature on hair colouring product use and risk of multiple myeloma, this question should be further evaluated in larger studies or consortia, and in high risk groups.
New species and new records of Delitschia from Venezuela
Authors: Jeng R. S. , Luck-Allen E. R. , Cain R. F.
Published: September 2008

Five new species of Delitschia from Venezuela are described and photographed. These are D. dochmiophragma on dung of horse, D. ionthada on dung of burro, D. mesostenospora on dung of burro, D. sexdecimspora on dung of horse, and D. spiralirima on dung of cow. The genus Delitschia is restricted to species in which the bitunicate asci have dark, two-celled ascospores, each cell being provided with an elongated germ slit, surrounded by a gelatinous sheath. Additional records are included for three previously described species.
Electrical characteristics of cells from leaves of Lycopersicon
Authors: Cheeseman John M. , Pickard Barbara G.
Published: September 2008

Microelectrode techniques were used to investigate the electrical properties of leaf cells of Lycopersicon esculentum both in excised leaflets and in small tissue sections. Most of the recordings were from epidermal cells of the abaxial midrib.Cells were electrically coupled. Apparent resistivity was lowest shortly after impalement (mean value about 1.8 kΩ cm−2) and increased gradually during most experiments. A fluctuation of resistance and potential occurred during the first 5–10 min of many recordings.Potentials between the vacuole and external medium averaged about −125 mV in all preparations, regardless of the external K+ content. Vacuolar K+ activity averaged about 66 mM. The average Nernst potential for K+ would thus be only about −48 mV for an external concentration of 10 mM. Changes of external pH between 5.6 and 8.6 had little or no effect on the potential, but at 4.6 the cells depolarized to about −50 mV and required about 2 h to recover after the pH was raised to 6.6. The potentials were partially dependent on metabolic activity, since CN− or CN− and SHAM together caused marked depolarization.Darkening and illuminating leaf mesophyll cells elicited reproducible transients; associated with the transient light-induced depolarization was a 10–15 mV spike. Changes in illumination had extremely variable effects on the potential of midrib epidermal cells.
Morphology and ontogeny of microbodies in the oomycete fungus Sapromyces elongatus
Authors: Heath I. Brent
Published: September 2008

Ultrastructural observations on microbodies in hyphae and sporangia of the oomycete fungus Sapromyces elongatus reveal that they consistently develop adjacent to cisternae of endoplasmic reticulum. At maturity they contain a crystalline structure, having a tetragonal lattice with asymmetric spacings of 12 and 13 nm and also several small irregular tubular structures. Mature microbodies also develop numerous villous invaginations, each filled with a cistema of endoplasmic reticulum, the membrane of which is constantly spaced from, and possibly cross bridged to, the microbody membrane. Although microbodies may be appressed to mitochondria, they do not show any associations with lipid droplets. In apparent senescence the crystals remain, but the microbody membrane enlarges greatly with accompanying loss of associated endoplasmic reticulum and dilution of matrix, so that the last recognizable stage is a crystal-containing vacuole. Zoospores contain numerous mature, invaginated microbodies associated with cisternae of endoplasmic reticulum; they are clustered predominantly around the nucleus. The morphology of the microbodies and their possession of crystalline inclusions differ from previously reported oomycete microbodies and may have taxonomic value, whereas the postulated ontogenic sequence and fate of the microbodies are previously unreported and may represent a general mechanism for microbody breakdown.
Cytological investigation of the Achillea millefolium complex (Compositae) in Quebec
Authors: Gervais Camille
Published: September 2008

The study of the chromosome numbers of over 112 individuals belonging to the Achillea millefolium L. complex (Compositae) and the examination of the pollen of about 200 herbarium specimens have led to the following conclusions; the A. millefolium complex, in Quebec, includes tetraploids (2n = 36), hexaploids (2n = 54), and various hybrid types. Tetraploids could be divided into two taxa: the southernmost is A. lanulosa Nutt. with small pollen grains and light brown or yellowish-margined phyllaries while the northern or alpine plants, corresponding to A. nigrescens (E. Mey.) Rydb., possess large pollen grains and dark-margined phyllaries. The two species, in contact zones, seem to hybridize freely. Hexaploids comprise purple-flowered introduced individuals escaping from cultivation, white or pink individuals, also introduced, and possibly a native taxon. The introduced hexaploids belong to A. millefolium s.str. and the purple-flowered variety frequently hybridizes with A. lanulosa giving rise to pentaploids (2n = 45) apparently almost sterile. A few plants from Maine (U.S.A.) have also been studied. This paper finally reports cytological observations related particularly to spontaneous mitotic abnormalities (fragmentation, fusion of chromosomes) affecting root tip cells of seedlings.
Electron-probe microassay studies of silicon deposits in the roots of two species of Andropogon
Authors: Sangster A. G.
Published: September 2008

Nodal roots of soil-grown specimens of Andropogon gerardii Vitman and A. scoparius Michx. were subjected to Si microassay by means of the electron-probe microanalyzer and the scanning electron microscope.Si was confined to the inner tangential wall of the tertiary-state endodermal cells in the form of nodular silica aggregates. Comparisons are made between the two species in terms of the morphology of these aggregates and the Si microassay values. The results are discussed in relation to previous studies of endodermal silicification in Sorghum roots and in relation to other genera within the Andropogoneae.
A contribution to the taxonomy of Antennaria alpina var. media, A. microphylla, and A. umbrinella in western North America
Authors: Douglas George W. , Denford Keith E. , Karas Ilana
Published: September 2008

The data examined during this study indicate that within the Antennaria alpina group in western North America only A. alpina var. media, A. microphylla, and A. umbrinella should be considered as distinct taxa. The numerous minor variants previously recognized by some taxonomists should be reduced to synonomy since examination of large amounts of material, from throughout western North America, defy further taxonomic segregation.
Colonization of rosin-coated slides by aquatic hyphomycetes
Authors: Bärlocher Felix , Kendrick Bryce , Michaelides John
Published: September 2008

Glass slides with a thin coat of rosin were immersed in a stream. After 1 to 6 days they were recovered and examined under the microscope for trapped conidia of aquatic hyphomycetes. A total of nine species could be observed on such slides. By a filtering method, conidia of nine aquatic species were found; eight of them were identical with those trapped on slides. This suggests the use of rosin-coated slides for a simple and fast evaluation of the mycoflora of streams.
Influence de la photopériode sur le comportement du méristème caulinaire du Celosia cristata
Authors: Driss-Ecole D.
Published: September 2008

Three groups of plants of Celosia cristata were grown in a 8-h, 12-h, or 16-h day. Histological studies of the shoot apex were performed during the vegetative and the prefloral phases.The apical meristems of the plants subjected to long-day conditions (16 h) flatten (fasciation). At the beginning of the fasciation, an activation of the corpus and a restructuration of the meristem are observed. The transformed meristem shows four superficial layers which cover a group of differentiated cells. The zonation is always recognizable and the apex initiates numerous leaves. The broadening of the meristem is due to the high level of mitotic activity of two opposite regions in the ‘anneau initial’ which takes an elliptical shape and to the peculiar orientation of the mitoses. During this transformation the volumes of the lateral and medullary zones increase while the volume of the axial zone remains almost identical. The long vegetative phase ceases with the homogeneization of the meristematic state of the four superficial layers and with the edification of a prefloral crest.The apex of plants grown under an 8-h photoperiod remains small sized. They never undergo fasciation and reach the prefloral phase very quickly.The meristems of the plants cultivated under 12 h of light daily show an unstable state and sometimes evolve tardily towards fasciation.
Variation saisonnière des cristaux d'oxalate de calcium des tissus de Vigne vierge
Authors: Calmés Jean , Piquemal Michel
Published: September 2008

The occurrence of crystals of calcium oxalate increases with increasing growth rate of the Virginia creeper (Parthenocissus tricuspidata Planchon). They are not an end product of metabolism but can partly reenter in the metabolism especially when buds start in the spring. Radioactivity from [14C]oxalate supplied in situ is recovered in glycolate, glycine, serine, and glycerate, all intermediates of the glycolate pathway, whereas a small fraction is evolved as photorespiratory CO2.
Pseudanuretes papernai sp.nov. (Copepoda: Caligidae) with comments on the genus Pseudanuretes Yamaguti, 1936
Authors: Kabata Z. , Deets G. B.
Published: September 2008

A new species of the genus Pseudanuretes, Pseudanuretes papernai (Copepoda: Caligidae), is described and illustrated. The new species is parasitic on Pomacanthus imperator (Pisces: Chaetodontidae) in the Gulf of Aqaba. The genus is discussed and the value of the fourth leg as a discriminant at the generic level in the family Caligidae is questioned.
Fluid shear stress modulates endothelial cell invasion into three-dimensional collagen matrices
Authors: Kang Hojin , Bayless Kayla J. , Kaunas Roland
Published: September 2008

Endothelial cells are subjected to biochemical and mechanical stimuli, which regulate their angiogenic potential. We determined the synergistic effects of sphingosine-1-phosphate (S1P) and fluid wall shear stress (WSS) on a previously established model of human umbilical vein endothelial cell invasion into three-dimensional collagen matrices. Collagen matrices were incorporated into a parallel-plate flow chamber to apply controlled WSS to the surface of endothelial monolayers over a period of 24 h. Cell invasion required the presence of S1P, with the effects of S1P being enhanced by shear stress to an extent comparable with S1P combined with angiogenic growth factor stimulation. The number of invading cells depended on the magnitude of shear stress, with a maximal induction at a shear stress of ∼5 dyn/cm2, whereas the invasion distance was proportional to the magnitude of shear stress. The enhancement of invasion by 5.3 dyn/cm2shear stress coincided with elevated phosphorylation of Akt and matrix metalloproteinase (MMP)-2 activation. Furthermore, invasion induced by the combined application of WSS and S1P was attenuated by inhibitors of MMPs (GM6001) and the phosphatidylinositol 3-kinase/Akt signaling pathway (wortmannin). These results provide evidence that shear stress is a positive modulator of S1P-induced endothelial cell invasion into collagen matrices through enhanced Akt and MMP-2 activation.
Role of estrogen receptor subtypes in estrogen-induced organ-specific vasorelaxation after trauma-hemorrhage
Authors: Ba Zheng F. , Chaudry Irshad H.
Published: September 2008

Although endothelin-1 (ET-1)-induced organ hypoperfusion after trauma-hemorrhage is improved by estrogen administration, it remains unclear whether estrogen receptor (ER) subtypes play any role in the attenuation of ET-1-induced vasoconstriction in any specific organ bed. To investigate this, isolated perfusion experiments in the heart, liver, small intestine, kidney, and lung were carried out in sham, at the time of maximum bleedout (MBO; i.e., 5-cm midline incision, with removal of 60% of circulating blood volume over 45 min to maintain a mean blood pressure of 40 mmHg), and 2 h after trauma-hemorrhage and resuscitation (T-H/R). Organ-specific ET-1-induced vasoconstriction was evaluated, and the effects of 17β-estradiol (E2) and ER-specific agonists propylpyrazole triol (PPT; ERα agonist) and diarylpropionitrile (DPN; ERβ agonist) were determined. ET-1 induced the greatest vasoconstriction in sham animals, with the strongest response in the kidneys, followed by the small intestine and liver. ET-1-induced responses were weakest in the heart and lungs. ET-1-induced vasoconstriction was evident at the time of MBO but was significantly decreased at 2 h after T-H/R. ERβ plays an important role in cardiac performance, as evidenced by improved heart performance (+dP/d t) in the presence of DPN. DPN also induced a greater effect than PPT in the reduction of ET-1-induced vasoconstriction in the kidneys and lungs. In contrast, PPT attenuated ET-1-induced vasoconstriction in the liver, whereas both DPN and PPT were equally effective in the small intestine. The increased +dP/d t values induced by E2, DPN, or PPT were evident at the time of MBO but were significantly decreased at 2 h after T-H/R. These data indicate that the effects of ET-1 on vasoconstriction and the role of ER subtypes in estrogen-induced vasorelaxation are organ specific and temporally specific after trauma-hemorrhage.
Role of CYP epoxygenases in A2AAR-mediated relaxation using A2AAR-null and wild-type mice
Authors: Nayeem Mohammed A. , Poloyac Samuel M. , Falck John R. , Zeldin Darryl C. , Ledent Catherine , Ponnoth Dovenia S. , Ansari Habib R. , Mustafa S. Jamal
Published: September 2008

We hypothesized that A2Aadenosine receptor (A2AAR) activation causes vasorelaxation through cytochrome P-450 (CYP) epoxygenases and endothelium-derived hyperpolarizing factors, whereas lack of A2AAR activation promotes vasoconstriction through Cyp4a in the mouse aorta. Adenosine 5′- N-ethylcarboxamide (NECA; 10−6M), an adenosine analog, caused relaxation in wild-type A2AAR (A2AAR+/+; +33.99 ± 4.70%, P < 0.05) versus contraction in A2AAR knockout (A2AAR−/−; −27.52 ± 4.11%) mouse aortae. An A2AAR-specific antagonist (SCH-58261; 1μM) changed the NECA (10−6M) relaxation response to contraction (−35.82 ± 4.69%, P < 0.05) in A2AAR+/+aortae, whereas no effect was noted in A2AAR−/−aortae. Significant contraction was seen in the absence of the endothelium in A2AAR+/+(−2.58 ± 2.25%) aortae compared with endothelium-intact aortae. An endothelial nitric oxide synthase inhibitor ( N-nitro-l-arginine methyl ester; 100 μM) and a cyclooxygenase inhibitor (indomethacin; 10 μM) failed to block NECA-induced relaxation in A2AAR+/+aortae. A selective inhibitor of CYP epoxygenases (methylsulfonyl-propargyloxyphenylhexanamide; 10 μM) changed NECA-mediated relaxation (−22.74 ± 5.11% at 10−6M) and CGS-21680-mediated relaxation (−18.54 ± 6.06% at 10−6M) to contraction in A2AAR+/+aortae, whereas no response was noted in A2AAR−/−aortae. Furthermore, an epoxyeicosatrienoic acid (EET) antagonist [14,15-epoxyeicosa-5( Z)-enoic acid; 10 μM] was able to block NECA-induced relaxation in A2AAR+/+aortae, whereas ω-hydroxylase inhibitors (10 μM dibromo-dodecenyl-methylsulfimide and 10 μM HET-0016) changed contraction into relaxation in A2AAR−/−aorta. Cyp2c29 protein was upregulated in A2AAR+/+aortae, whereas Cyp4a was upregulated in A2AAR−/−aortae. Higher levels of dihydroxyeicosatrienoic acids (DHETs; 14,15-DHET, 11,12-DHET, and 8,9-DHET, P < 0.05) were found in A2AAR+/+versus A2AAR−/−aortae. EET levels were not significantly different between A2AAR+/+and A2AAR−/−aortae. It is concluded that CYP epoxygenases play an important role in A2AAR-mediated relaxation, and the deletion of the A2AAR leads to contraction through Cyp4a.
Integrin-linked kinase regulates smooth muscle differentiation marker gene expression in airway tissue
Authors: Wu Yidi , Huang Youliang , Herring B. Paul , Gunst Susan J.
Published: September 2008

Phenotypic changes in airway smooth muscle occur with airway inflammation and asthma. These changes may be induced by alterations in the extracellular matrix that initiate signaling pathways mediated by integrin receptors. We hypothesized that integrin-linked kinase (ILK), a multidomain protein kinase that binds to the cytoplasmic tail of β-integrins, may be an important mediator of signaling pathways that regulate the growth and differentiation state of airway smooth muscle. We disrupted signaling pathways mediated by ILK in intact differentiated tracheal muscle tissues by depleting ILK protein using ILK antisense. The depletion of ILK protein increased the expression of the smooth muscle differentiation marker genes myosin heavy chain (SmMHC), SM22α, and calponin and increased the expression of SmMHC protein. Conversely, the overexpression of ILK protein reduced the mRNA levels of SmMHC, SM22α, and calponin and SmMHC protein. Analysis by chromatin immunoprecipitation showed that the binding of the transcriptional regulator serum response factor (SRF) to the promoters of SmMHC, SM22α, and calponin genes was increased in ILK-depleted tissues and decreased in tissues overexpressing ILK. ILK depletion also increased the amount of SRF that localized within the nucleus. ILK depletion and overexpression, respectively, decreased and increased the activation of its downstream substrate protein kinase B (PKB/Akt). The pharmacological inhibition of Akt activity also increased SRF binding to the promoters of smooth muscle-specific genes and increased expression of smooth muscle proteins, suggesting that ILK may exert its effects by regulating the activity of Akt. We conclude that ILK is a critical regulator of airway smooth muscle differentiation. ILK may mediate signals from integrin receptors that control airway smooth muscle differentiation in response to alterations in the extracellular matrix.
Effects of melatonin in an experimental model of ventilator-induced lung injury
Authors: Pedreira Paula R. , García-Prieto Emilio , Parra Diego , Astudillo Aurora , Diaz Elena , Taboada Francisco , Albaiceta Guillermo M.
Published: September 2008

Melatonin is a free radical scavenger and a broad-spectrum antioxidant and has well-documented immunomodulatory effects. We studied the effects of this hormone on lung damage, oxidative stress, and inflammation in a model of ventilator-induced lung injury (VILI), using 8- to 12-wk-old Swiss mice ( n = 48). Animals were randomized into three experimental groups: control (not ventilated); low-pressure ventilation [peak inspiratory pressure 15 cmH2O, positive end-expiratory pressure (PEEP) 2 cmH2O], and high-pressure ventilation (peak inspiratory pressure 25 cmH2O, PEEP 0 cmH2O). Each group was divided into two subgroups: eight animals were treated with melatonin (10 mg/kg ip, 30 min before the onset of ventilation) and the remaining eight with vehicle. After 2 h of ventilation, lung injury was evaluated by gas exchange, wet-to-dry weight ratio, and histological analysis. Levels of malondialdehyde, glutathione peroxidase, interleukins IL-1β, IL-6, TNF-α, and IL-10, and matrix metalloproteinases 2 and 9 in lung tissue were measured as indicators of oxidation status, pro-/anti-inflammatory cytokines, and matrix turnover, respectively. Ventilation with high pressures induced severe lung damage and release of TNF-α, IL-6, and matrix metalloproteinase-9. Treatment with melatonin improved oxygenation and decreased histological lung injury but significantly increased oxidative stress quantified by malondialdehyde levels. There were no differences in TNF-α, IL-1β, IL-6, or matrix metalloproteinases caused by melatonin treatment, but IL-10 levels were significantly higher in treated animals. These results suggest that melatonin decreases VILI by increasing the anti-inflammatory response despite an unexpected increase in oxidative stress.
Mechanical stretch decreases migration of alveolar epithelial cells through mechanisms involving Rac1 and Tiam1
Authors: Desai Leena P. , Chapman Kenneth E. , Waters Christopher M.
Published: September 2008

Mechanical ventilation can overdistend the lungs or generate shear forces in them during repetitive opening/closing, contributing to lung injury and inflammation in patients with acute respiratory distress syndrome (ARDS). Repair of the injured lung epithelium is important for restoring normal barrier and lung function. In the current study, we investigated the effects of cyclic mechanical strain (CS), constant distention strain (CD), and simulated positive end-expiratory pressure (PEEP) on activation of Rac1 and wound closure of rat primary alveolar type 2 (AT2) cells. Cyclic stretch inhibited the migration of wounded AT2 cells in a dose-dependent manner with no inhibition occurring with 5% CS, but significant inhibition with 10% and 15% CS. PEEP conditions were investigated by stretching AT2 cells to 15% maximum strain (at a frequency of 10 cycles/min) with relaxation to 10% strain. AT2 cells were also exposed to 20% CD. All three types of mechanical strain inhibited wound closure of AT2 cells compared with static controls. Since lamellipodial extensions in migrating cells at the wound edge were significantly smaller in stretched cells, we measured Rac1 activity and found it to be decreased in stretched cells. We also demonstrate that Tiam1, a Rac1-specific guanine nucleotide exchange factor, was expressed mainly in the cytosol of AT2 cells exposed to mechanical strain compared with membrane localization in static cells. Downregulation of Tiam1 with 100 μM NSC-23766 inhibited activation of Rac1 and migration of AT2 cells, suggesting its involvement in repair mechanisms of AT2 cells subjected to mechanical strain.
Lubiprostone activates non-CFTR-dependent respiratory epithelial chloride secretion in cystic fibrosis mice
Authors: MacDonald Kelvin D. , McKenzie Karen R. , Henderson Mark J. , Hawkins Charles E. , Vij Neeraj , Zeitlin Pamela L.
Published: September 2008

Periciliary fluid balance is maintained by the coordination of sodium and chloride channels in the apical membranes of the airways. In the absence of the cystic fibrosis transmembrane regulator (CFTR), chloride secretion is diminished and sodium reabsorption exaggerated. ClC-2, a pH- and voltage-dependent chloride channel, is present on the apical membranes of airway epithelial cells. We hypothesized that ClC-2 agonists would provide a parallel pathway for chloride secretion. Using nasal potential difference (NPD) measurements, we quantified lubiprostone-mediated Cl− transport in sedated cystic fibrosis null (gut-corrected), C57Bl/6, and A/J mice during nasal perfusion of lubiprostone (a putative ClC-2 agonist). Baseline, amiloride-inhibited, chloride-free gluconate-substituted Ringer with amiloride and low-chloride Ringer plus lubiprostone (at increasing concentrations of lubiprostone) were perfused, and the NPD was continuously recorded. A clear dose-response relationship was detected in all murine strains. The magnitude of the NPD response to 20 μM lubiprostone was −5.8 ± 2.1 mV (CF, n = 12), −8.1 ± 2.6 mV (C57Bl/6 wild-type, n = 12), and −5.3 ± 1.2 mV (AJ wild-type, n = 8). A cohort of ClC-2 knockout mice did not respond to 20 μM lubiprostone ( n = 6, P = 0.27). In C57Bl/6 mice, inhibition of CFTR with topical application of CFTR inhibitor-172 did not abolish the lubiprostone response, thus confirming the response seen is independent of CFTR regulation. RT-PCR confirmed expression of ClC-2 mRNA in murine lung homogenate. The direct application of lubiprostone in the CF murine nasal airway restores nearly normal levels of chloride secretion in nasal epithelia.
Effects of distension on airway inflammation and venular P-selectin expression
Authors: Moldobaeva Aigul , Jenkins John , Wagner Elizabeth
Published: September 2008

We previously have shown in mice and rats, enhanced leukocyte recruitment to airway postcapillary venules after excessive distention imposed by the application of positive end-expiratory pressure. Because P-selectin was shown to be essential for this outcome, we sought to establish an in vitro endothelial cell model and determine the mechanisms whereby mechanical distension alters adhesion molecule expression. P-selectin surface expression on mouse jugular vein endothelial cells exposed to cyclic stretch (5 or 20% elongation for 5 min; Flexercell) were compared with static cells. The larger, pathophysiological regimen of cyclic stretch showed a 54% increase in P-selectin expression after stretch compared with static cells. This response was attenuated but confirmed in tracheal venular endothelium (29% increase). We questioned whether these changes were dependent on increases in intracellular Ca2+through voltage-gated Ca2+channels. The stretch-induced increase in P-selectin expression was substantially decreased by pretreatment with the T-type Ca2+channel inhibitor mibefradil (76% inhibition). Furthermore, when the Cav3.1 T-type Ca2+channel expression was decreased in both endothelial cell subtypes with specific small-interfering RNA, the distension-induced expression of P-selectin decreased to levels less than that observed in static cells. We conclude that P-selectin expression on systemic venular endothelial cells contributes to a proinflammatory phenotype after mechanical stretch and can be selectively modulated by voltage-gated calcium channel inhibition.