Tadpoles rely on mechanosensory stimuli for communication when visual capabilities are poor.

The ways in which animals sense the world changes throughout development. For example, young of many species have limited visual capabilities, but still make social decisions, likely based on information gathered through other sensory modalities. Poison frog tadpoles display complex social behaviors that have been suggested to rely on vision despite a century of research indicating tadpoles have poorly-developed visual systems relative to adults. Alternatively, other sensory modalities, such as the lateral line system, are functional at hatching in frogs and may guide social decisions while other sensory systems mature. Here, we examined development of the mechanosensory lateral line and visual systems in tadpoles of the mimic poison frog (Ranitomeya imitator) that use vibrational begging displays to stimulate egg feeding from their mothers. We found that tadpoles hatch with a fully developed lateral line system. While begging behavior increases with development, ablating the lateral line system inhibited begging in pre-metamorphic tadpoles, but not in metamorphic tadpoles. We also found that the increase in begging and decrease in reliance on the lateral line co-occurs with increased retinal neural activity and gene expression associated with eye development. Using the neural tracer neurobiotin, we found that axonal innervations from the eye to the brain proliferate during metamorphosis, with few retinotectal connections in recently-hatched tadpoles. We then tested visual function in a phototaxis assay and found tadpoles prefer darker environments. The strength of this preference increased with developmental stage, but eyes were not required for this behavior, possibly indicating a role for the pineal gland. Together, these data suggest that tadpoles rely on different sensory modalities for social interactions across development and that the development of sensory systems in socially complex poison frog tadpoles is similar to that of other frog species.

On-treatment blood pressures of older hypertensive patients in Canada: implications for Systolic blood PRessure INtervention Trial.

OBJECTIVE: The therapeutic target level for the blood pressure (BP) on antihypertensive drug treatment in older hypertensive patients is still extensively debated. We assessed the achieved BP levels in older treated hypertensive patients in a representative sample of the population. DESIGN: During the 2006 Ontario Survey on the Prevalence and Control of Hypertension, BP (using the SPRINT protocol) and treatment data were collected in 2551 respondents from a random and representative sample of the adult (20-79 years) population. Responses are weighted to the Ontario hypertensive population of 1367 384, of which 684 928 were in the 60-79-year age range. RESULTS: Among 60-79-year-old individuals, using traditional definitions the prevalence of hypertension was 49%. Hypertension treatment rates were high (85%) as were control rates among treated hypertensive patients (85% for 60-69-year-old and 70% for 70-79-year-old patients). A total of 38% of older hypertensive patients were treated with a single antihypertensive drug. A total of 54% of these had a SBP less than 130 mmHg and 23% less than 120 mmHg. Of those treated with combination therapy, 75% had a SBP less than 130 mmHg, and 44% had a SBP less than 120 mmHg. For treated and controlled hypertensive patients, average SBP was 120 mmHg for the 60-69-year age groups, and 119 mmHg in the 70-79-year age groups. CONCLUSION: These findings suggest that intensive BP control, now being considered for high-risk hypertensive patients based on results from SPRINT, was actually already being achieved ∼10 years ago in a large section of the general hypertensive population of Ontario, Canada.

What is the feasibility of implementing effective sodium reduction strategies to treat hypertension in primary care settings? A systematic review.

OBJECTIVE: To evaluate whether efficacious counseling methods on sodium restriction can be successfully incorporated into primary care models for the management of hypertension. METHODS: We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Database of Abstracts of Reviews of Effects and Health Technology Assessment to identify randomized controlled trials of dietary counseling for salt intake reduction that reported significant reduction in 24-h urinary sodium and blood pressure levels among adults with untreated hypertension. Data extraction and assessment of reproducibility and feasibility were done in duplicate and any disagreements were resolved by consensus. RESULTS: Six trials were included for assessment of methods as they were efficacious in reducing sodium intake (24-h urinary sodium excretion) by 73 to 93 mmol/day (intervention) vs. 3.2 to 12.5 mmol/day (control). This was paralleled with a reduction in blood pressure (-4 to -27  mmHg) between groups. In four of the six trials, the methods were described in sufficient detail to be reproducible, but in none of these trials were the 'counseling methods' feasible for application in primary care settings. Apart from multiple sessions of counseling, the reported interventions were supplemented with provision of prepared food, community cooking classes, and intensive inpatient training sessions. CONCLUSION: Despite the availability of efficacious counseling methods for the reduction of sodium intake among newly diagnosed hypertensive patients (feasible within a clinical trial setting), none of these methods, in their present form, are suitable for incorporation into existing primary care settings in countries such as Canada, United States, and UK.