Image velocimetry and spectral analysis enable quantitative characterization of larval zebrafish gut motility.

BACKGROUND: Normal gut function requires rhythmic and coordinated movements that are affected by developmental processes, physical and chemical stimuli, and many debilitating diseases. The imaging and characterization of gut motility, especially regarding periodic, propagative contractions driving material transport, are therefore critical goals. Previous image analysis approaches have successfully extracted properties related to the temporal frequency of motility modes, but robust measures of contraction magnitude, especially from in vivo image data, remain challenging to obtain. METHODS: We developed a new image analysis method based on image velocimetry and spectral analysis that reveals temporal characteristics such as frequency and wave propagation speed, while also providing quantitative measures of the amplitude of gut motion. KEY RESULTS: We validate this approach using several challenges to larval zebrafish, imaged with differential interference contrast microscopy. Both acetylcholine exposure and feeding increase frequency and amplitude of motility. Larvae lacking enteric nervous system gut innervation show the same average motility frequency, but reduced and less variable amplitude compared to wild types. CONCLUSIONS & INFERENCES: Our image analysis approach enables insights into gut dynamics in a wide variety of developmental and physiological contexts and can also be extended to analyze other types of cell movements.

Wave intensity analysis in the internal carotid artery of hypertensive subjects using phase-contrast MR angiography and preliminary assessment of the effect of vessel morphology on wave dynamics.

OBJECTIVE: Hypertension is associated with reduced cerebral blood flow, but it is not known how this impacts on wave dynamics or potentially relates to arterial morphology. Given the location of the internal carotid artery (ICA) and risks associated with invasive measurements, wave dynamics in this artery have not been extensively assessed in vivo. This study explores the feasibility of studying wave dynamics in the internal carotid artery non-invasively. APPROACH: Normotensive, uncontrolled and controlled hypertensive participants were recruited (daytime ambulatory blood pressure <135/85 mmHg and >135/85 mmHg, respectively; n = 38). Wave intensity, reservoir pressure and statistical shape analyses were performed on the right ICA and ascending aorta high-resolution phase-contrast magnetic resonance angiography data. MAIN RESULTS: Wave speed in the aorta was significantly lower in normotensive compared to hypertensive participants (6.7 ± 1.8 versus 11.2 ± 6.2 m s-1 for uncontrolled and 11.8 ± 4.6 m s-1 for controlled hypertensives, p = 0.02), whilst there were no differences in wave speed in the ICA. There were no significant differences between the groups for the wave intensity or reservoir pressure. Interestingly, a significant association between the anatomy of the ICA and wave energy (FCW and size, r 2 = 0.12, p = 0.04) was found. SIGNIFICANCE: This study shows it is feasible to study wave dynamics in the ICA non-invasively. Whilst changes in aortic wave speed confirmed an expected increase in arterial stiffness, this was not observed in the ICA. This might suggest a protective mechanism in the cerebral circulation, in conjunction with the effect of vessel tortuosity. Furthermore, it was observed that ICA shape correlated with wave energy but not wave speed.

Bugs, guts and brains, and the regulation of food intake and body weight.

The microbiota-gut-brain axis is currently being explored in many types of rodent models, including models of behavioral, neurodegenerative and metabolic disorders. Our laboratory is interested in determining the mechanisms and consequences of activation of vagal afferent neurons that lead to activation of parasympathetic reflexes and changes in feeding behavior in the context of obesity. Obesity is associated with microbial dysbiosis, decreased intestinal barrier function, gut inflammation, metabolic endotoxemia, chronic low-grade systemic inflammation and desensitization of vagal afferent nerves. This review will present the evidence that altered gut microbiota together with decreased gut barrier function allows the passage of bacterial components or metabolites in obese individuals, leading to the disruption of vagal afferent signaling and consequently resulting in an increase in body weight. We first review the most recent descriptions of gut microbial dysbiosis due to a high fat diet and describe changes in the gut barrier and the evidence of increased intestinal permeability in obesity. We then will review the evidence to show how manipulating the gut microbiota via pre and probiotics can restore gut barrier function and prevent weight gain. Lastly, we present possible mechanisms by which the microbe-gut-brain axis may have a role in obesity. The studies mentioned in this review have provided new targets to treat and prevent obesity and have highlighted how the microbiota-gut-brain axis is involved.

External fixation of facial fractures.

Although external fixation is not indicated in every type of facial fracture, its use alone or with intermaxillary or internal fixation may be of benefit with problems resulting from avulsed segments, infection, inadequate previous reduction, delayed reduction, severe displacement and comminution, non-union, cerebrospinal fluid leak or where a combination of these factors exists. The judicious application of extraskeletal fixation can save valuable anesthetic time as well as assure accesibility of the pharynx and maintenance of an airway and routes for nutrition when these might otherwise be compromised. Although extraskeletal fixation is not withou problems or contraindications, it must be weighed in view of the patient's physical, mental and neurological status, and the existence of concomitant injuries.

The Health and Activity Limitation Survey. Disabled aboriginal persons in Canada.

In 1986, out of a total of 711,725 Canadians of aboriginal ancestry, 86,505 reported having some level of disability. This article profiles disabled aboriginal persons living both on-and off-reserve, presenting data from Statistics Canada's 1986 Census of Population and the Health and Activity Limitation Survey (HALS), conducted in 1986 and 1987. Census data provide an overview of selected demographic and socio-economic characteristics of the disabled aboriginal population. HALS data provide details on the nature and number of disabilities, underlying causes of the disabilities, and the degree of assistance required for daily activities. Accidents were frequently cited as the underlying cause of disability among disabled aboriginal people living both on- and off-reserve. Most disabled original persons aged 15 and older were able to perform household duties such as preparation of meals, shopping and housework. On-reserve disabled aboriginal persons did, however, require and receive help more frequently than those who resided off-reserve.

The Health and Activity Limitation Survey.

The Health and Activity Limitation Survey was the first post-censal survey to be conducted immediately following the 1986 Census of Population. A comprehensive survey of persons with disabilities, the sample included 184,500 persons residing in households and 19,100 individuals in health related institutions. Data gathered included the nature and severity of the individual's disability and the barriers disabled persons might encounter in their daily activities. The survey showed that an estimated 3.3 million Canadians, or 13% of the population, experienced some level of disability. The survey also showed a significant increase in disability with age. While 5% of children aged 0-14 had a disability, in the population aged 15-64, 11% were disabled. The prevalence increased to 46% for the population aged 65 and older. Disabilities related to mobility were reported by approximately 2 million persons or just under two thirds of the disabled population aged 15 and older. Of the 1.8 million adults aged 15-64 with a disability, approximately 56% reported an income of under $10,000 and 1985, while 12.5% $30,000 or more.

Treatment of mandibular prognathism in an acromegalic patient.

A 41-year-old man with acromegaly underwent cryosurgery for a pituitary adenoma. Although soft tissue regression is possible after pituitary ablation, bony changes are permanent. Thus, bilateral vertical osteotomies and bilateral coronoidotomies were performed for correction of the mandibular prognathism. The postoperative occlusion and facial profile were very acceptable. Unfortunately, the patient died of a myocardial infarction eight days postoperatively.