Cilia-driven rotational behavior displayed by embryos of the pond snail Helisoma trivolvis was characterized in terms of its behavioral subcomponents, developmental changes, and response to exogenous serotonin. Rotation was found to be a complex behavior characterized by four parameters; rotational direction, rotation rate, rotational surges, and periods of inactivity. These parameters all exhibited characteristic developmental changes from embryonic stage E15 through stage E30. Notably, both rotation rate and frequency of rotational surges increased from stage E15 to E25 and declined to an intermediate level by stage E30. It appeared that the developmental increase in overall rotation rate was caused primarily by an increase in surge frequency, rather than an increase in the rate of nonsurge rotation. Immersion of embryos inserotonin-containing pond water resulted in a dose-dependent, reversible increase in rotation rate as well as a dose-dependent, reversible decrease in surge frequency. The serotonin antagonist, mianserin, abolished the excitatory effect of exogenous serotonin. Furthermore, application of mianserin alone reduced rotation rate and virtually abolished rotational surges. Taken together, these pharmacological results suggest that endogenous serotonin is responsible for generating rotational surges. Given that early embryos contain only a single pair of serotonergic neurons (Goldberg and Kater, 1989) during the stages when rotational surges are expressed, these results also prompt the hypothesis that these neurons, embryonic neurons C1, act as cilioexcitatory motor neurons during embryonic development.

The Saskatchewan Farm Injury Cohort (SFIC) is a major new Canadian study that was developed to evaluate potential causes of injury among farmers and their family members. The cohort involves 2,390 farms and 5,492 farm people being followed over a two-year period. The article describes the rationale and methodology for the baseline and longitudinal components of this study. The SFIC is one of the first studies to apply population health theory to the modeling of risks for injury in a defined Canadian population. In doing so, the relative influence of several potential causes of farm injury, including physical, socioeconomic, and cultural factors, will be estimated. Study findings will inform the content and targeting of injury prevention initiatives specific to the farm occupational environment.

In contrast to the abundance of information on the many physiological and developmental actions of serotonin in molluscan nervous systems, comparatively little is known about the serotonin receptors involved in these responses. Embryos of the pulmonate gastropod, Helisoma trivolvis, display a cilia-driven rotational behavior that is regulated by endogenous serotonin. In the present study, two functional assays were used to determine some of the pharmacological properties of the receptors that mediate the cilio-excitatory action of serotonin. Time-lapse video microscopy was used to measure whole embryo rotation rate and cilia beat frequency in isolated cells. In dose-response experiments, serotonin was approximately 10 times more potent in stimulating cilia beat frequency over embryo rotation. In rotation experiments, 5-carboxyamidotryptamine and methysergide had effective agonist activity in dose ranges similar to that of serotonin (1 to 100 microM). In contrast, 8-hydroxydipropylaminotetralin HBr (8-OH-DPAT) displayed agonist activity of lower potency and effectiveness. Several compounds displayed antagonist activity in the 1 to 100 microM dose range, including mianserin, spiperone, ritanserin, 1-(1-naphthyl)piperazine, and propranolol. alpha-Methylserotonin had mixed agonist-antagonist activity, and metoclopramide, MDL-72222, and ketanserin were inactive. Experiments on isolated cells suggested that the extremely effective antagonism displayed by mianserin in the embryo rotation assay was due to its specific activity at ciliary serotonin receptors. These results implicate the presence of a novel serotonin receptor on embryonic ciliated cells that is pharmacologically distinct from those previously characterized in vertebrate or invertebrate systems.

The adverse respiratory effects of agricultural dust inhalation are mediated in part by endotoxin, a constituent of gram-negative bacterial cell walls. This study quantified personal work-shift exposures to inhalable dust, endotoxin, and its reactive 3-hydroxy fatty acid (3-OHFA) constituents among workers in grain elevators, cattle feedlots, dairies, and on corn farms. Exposures were compared with post-work-shift nasal lavage fluid inflammation markers and respiratory symptoms. Breathing-zone personal air monitoring was performed over one work shift to quantify inhalable dust (Institute of Medicine samplers), endotoxin (recombinant factor C [rFC] assay), and 3-OHFA (gas chromatography/mass spectrometry). Post-shift nasal lavage fluids were assayed for polymorphonuclear neutrophils (PMN), myeloperoxidase (MPO), interleukin 8 (IL-8), albumin, and eosinophilic cation protein (ECP) concentrations. The geometric mean (GSD) of endotoxin exposure (rFC assay) among the 125 male participants was 888 +/- (6.5) EU/m(3), and 93% exceeded the proposed exposure limit (50 EU/m(3)). Mean PMN, MPO, albumin, and ECP levels were two- to threefold higher among workers in the upper quartile of 3-OHFA exposure compared to the lowest exposure quartile. Even numbered 3-OHFA were most strongly associated with nasal inflammation. Symptom prevalence was not elevated among exposed workers, possibly due to endotoxin tolerance or a healthy worker effect in this population. This is the first study to evaluate the relationship between endotoxin's 3-OHFA constituents in agricultural dust and nasal airway inflammation. More research is needed to characterize the extent to which these agents contribute to respiratory disease among agricultural workers.

BackgroundTo date, determinants of respiratory health in First Nations people living on reserves and means of addressing and redressing those determinants have not been well established. Hence the Saskatchewan First Nations Lung Health Project (FNLHP) is a new prospective cohort study of aboriginal people being conducted in two First Nations reserves to evaluate potential health determinants associated with respiratory outcomes. Using the population health framework (PHF) of Health Canada, instruments designed with the communities, joint ownership of data, and based on the 4-phase concept of the First Nations Regional Longitudinal Health Survey, the project aims to evaluate individual factors, contextual factors, and principal covariates on respiratory outcomes. The objective of this report is to clearly describe the methodology of (i) the baseline survey that consists of two components, an interviewer-administered questionnaire and clinical assessment; and (ii) potential intervention programs; and present descriptive results of the baseline data of longitudinal FNLHP.MethodsThe study is being conducted over 5 years (2012–2017) in two phases, baseline and longitudinal. Baseline survey has been completed and consisted of (i) an interviewer-administered questionnaire-based evaluation of individual and contextual factors of importance to respiratory health (with special focus on chronic bronchitis, chronic obstructive pulmonary disease, asthma and obstructive sleep apnea), and (ii) clinical lung function and allergy tests with the consent of study participants. The address-redress phase consists of potential intervention programs and is currently being rolled out to address-at community level (via green light program and environmental study), and redress-at policy level (via obesity reduction and improved diagnosis and treatment of obstructive sleep apnea) the issues that have been identified by the baseline data.ResultsInterviewer-administered surveys were conducted in 2012–2013 and collected data on 874 individuals living in 406 households from two reserve communities located in Saskatchewan, Canada. Four hundred and forty six (51%) females and 428 (49%) males participated in the FNLHP.ConclusionsThe information from this project will assist in addressing and redressing many of the issues involved including the provision of adequate housing, health lifestyle practices, and in planning for health service delivery.Electronic supplementary materialThe online version of this article (doi:10.1186/s13104-015-1137-5) contains supplementary material, which is available to authorized users.