Trying to explain an effect of "per se" hydrostatic pressure on heart rate in fish.

Specific effects of "per se" hydrostatic pressure on mean heart rate have been studied on eels (Anguilla anguilla L.), both untreated and treated with atropine and propranolol, and on isolated eel's heart. Because temperature brings, by itself, heart rate modifications in fish, a quantitative study was performed in order to take away the increment of heart rate due to the water warming, which cannot entirely be suppressed during compression. The specific effects of "per se" pressure have been identified as a bradycardia above 24.5 degrees C and as a tachycardia below this temperature. The use of atropine and propranol, which abolish extrinsic heart control, shows that pressure acts both through extrinsic mechanisms of heart control and through a direct action on autonomic cardiac cells. This effect of "per se" pressure on cardiac cells is interpreted according to chemical kinetics laws. The hypothesis that pressure acts at the molecular level, possibly by the means of reversible structure modifications of some molecules, is suggested.     

Surfer wipe out by predator fish

Needlefish injuries, commonly reported in the Indo-Pacific region, have not been previously reported along the European coastlines. This case report describes a penetrating injury to the heel of a professional surfer during competition off the Portuguese coast. Diagnostic as well as therapeutic recommendations are made.     

Muscle remodeling and the exercise physiology of fish

Fish muscle responds to aerobic exercise training and cold acclimation with a more aerobic muscle phenotype than mammalian muscle but through both conserved and distinct molecular events. Differences from mammals in exercise metabolism and diversity in protein isoforms suggest that the regulation of muscle fuel use is more complex in fish. This review considers fish as powerful models for exercise and muscle physiology.     

鱼刺穿透阑尾至腹腔1例

报告1例鱼刺穿透阑尾至腹腔的诊治体会,提示应注意全面询问病史和发病情况;术中操作应轻柔仔细,并强调养成良好的用餐习惯。     

Ra-226 bioaccumulation and growth indices in fish

Purpose: To determine the accumulated activity of Ra-226 in fathead minnows fed with environmentally relevant levels of Ra-226 for 5 months in water at 20?°C, and to evaluate the influence of this level of Ra-226 on the growth of fathead minnows.

Methods: Fathead minnows were fed with fish food containing 10–10,000 mBq/g Ra-226 for 5 months. At the end of the experiment, the fish were sacrificed, flash frozen in liquid nitrogen and kept at ?20?°C. Longitudinal sections of 40 μm thickness were cut at the middle of the fish body using a cryostat. The activity of Ra-226 in each section was determined using autoradiography with a nuclear track detector CR-39. According to the weight and the width of the fish, the activity of Ra-226 in the whole fish body could be estimated. In addition, the length and the weight of the fish were measured and the condition factor was calculated to evaluate the growth and fitness of the fish.

Results: There is a positive but non-linear relationship between the accumulated activity of Ra-226 in fish body and the concentration of Ra-226 in fish food. The highest activity of Ra-226 accumulated in fish body was found from fish fed with 10,000 mBq/g Ra-226 food. This was calculated as 256.4?±?49.1 mBq/g, p?<?0.05, and the calculated dose rate was 6.2?±?1.2 mGy/y. For fish fed with food containing lower concentration of Ra-226 (up to 1000 mBq/g), the bioaccumulation of Ra-226 in the body saturated. The Ra-226 concentration factor (CF) for fish was inversely proportional to the Ra-226 activity in food, and the highest CF value was 2.489, obtained from the lowest dietary Ra-226 activity (10 mBq/g). In addition, condition factors (K) of fish in all Ra-226-treated groups were significantly lower than those of the controls.

Conclusion: The results show that the bioaccumulation of Ra-226 in fish is not simply related to the dietary Ra-226 activity, and has a saturation value when the dietary activity is low. In addition, the environmental level of Ra-226 in the fish food has a small adverse effect on the growth and fitness of fathead minnows.     

Lethal fish hook attachment – An unusual occurrence

A 39-year-old fisherman is reported who was dragged into the water from a boat after he became entangled in fishing line. His death was attributed to salt water drowning. At autopsy the cause of death was confirmed and the mechanism of the lethal event elucidated. Specifically, a large fish hook attached to line was embedded in his right wrist. The hook had passed beneath flexor tendons and had firmly attached him to fishing line that was being dropped from the vessel. There were no other significant injuries or underlying diseases present. This case demonstrates another rare situation in the commercial fishing industry that may result in a victim being dragged from a boat and drowned.     

Maximal oxygen uptake "classical" versus "contemporary" viewpoints

In two articles Timothy Noakes proposes a new physiological model in which skeletal muscle recruitment is regulated by a central "govenor," specifically to prevent the development of a progressive myocardial ischemia that would precede the development of skeletal muscle anaerobiosis during maximal exercise. In this rebuttal to the Noakes' papers, we argue that Noakes has ignored data supporting the existing hypothesis that under normal conditions cardiac output is limiting maximal aerobic power during dynamic exercise engaging large muscle groups.