Sea urchin larvae utilize light for regulating the pyloric opening.

BACKGROUND: Light is essential for various biological activities. In particular, visual information through eyes or eyespots is very important for most of animals, and thus, the functions and developmental mechanisms of visual systems have been well studied to date. In addition, light-dependent non-visual systems expressing photoreceptor Opsins have been used to study the effects of light on diverse animal behaviors. However, it remains unclear how light-dependent systems were acquired and diversified during deuterostome evolution due to an almost complete lack of knowledge on the light-response signaling pathway in Ambulacraria, one of the major groups of deuterostomes and a sister group of chordates. RESULTS: Here, we show that sea urchin larvae utilize light for digestive tract activity. We found that photoirradiation of larvae induces pyloric opening even without addition of food stimuli. Micro-surgical and knockdown experiments revealed that this stimulating light is received and mediated by Go(/RGR)-Opsin (Opsin3.2 in sea urchin genomes) cells around the anterior neuroectoderm. Furthermore, we found that the anterior neuroectodermal serotoninergic neurons near Go-Opsin-expressing cells are essential for mediating light stimuli-induced nitric oxide (NO) release at the pylorus. Our results demonstrate that the light>Go-Opsin>serotonin>NO pathway functions in pyloric opening during larval stages. CONCLUSIONS: The results shown here will lead us to understand how light-dependent systems of pyloric opening functioning via neurotransmitters were acquired and established during animal evolution. Based on the similarity of nervous system patterns and the gut proportions among Ambulacraria, we suggest the light>pyloric opening pathway may be conserved in the clade, although the light signaling pathway has so far not been reported in other members of the group. In light of brain-gut interactions previously found in vertebrates, we speculate that one primitive function of anterior neuroectodermal neurons (brain neurons) may have been to regulate the function of the digestive tract in the common ancestor of deuterostomes. Given that food consumption and nutrient absorption are essential for animals, the acquirement and development of brain-based sophisticated gut regulatory system might have been important for deuterostome evolution.

Efficacy of argon plasma coagulation in the treatment of radiation-induced hemorrhagic gastroduodenal vascular ectasia.

OBJECTIVE: Radiation-induced hemorrhagic gastroduodenal vascular ectasia (GDVE) is rare but difficult to manage. Argon plasma coagulation (APC) has not yet been evaluated in the treatment of radiation-induced hemorrhagic GDVE. The efficacy of APC in patients with radiation-induced hemorrhagic GDVE has been investigated in this article. MATERIAL AND METHODS: Eighteen patients with upper gastrointestinal (GI) bleeding caused by radiation-induced GDVE, including 13 with hepatocellular carcinoma, 3 with pancreatic cancer, and 2 with cholangiocarcinoma, were treated with APC. The efficacy of APC was retrospectively evaluated, based on cessation of macroscopic GI bleeding, resolution or stabilization of anemia and transfusion dependence, endoscopic ablation of almost all vascular lesions, complications, and recurrence. RESULTS: Mean patient age was 59 years (range 42-80 years). The median time from radiation to GDVE diagnosis was 4.6 months (range 3.3-21.5 months). The median number of APC sessions per patient was 2.4 (range 1-4). All 18 patients showed an endoscopic response to APC treatment, with sustained increases in mean hemoglobin level, from 6.6 g/dL (range 2.9-9.5 g/dL) to 9.7 g/dL (range 7.1-12.7 g/dL) (p < 0.001), and decreased dependence on transfusion, from 9.1 (range 0-30) to 4.1 (range 0-15) units of packed red blood cells per patient (p = 0.038) after last endoscopic eradication by APC treatment. There were no major procedure-related adverse events or deaths. At a median follow up of 4.7 months (range 0.6-24.5 months), none of the patients experienced recurrence of GDVE. CONCLUSIONS: APC showed short-term effectiveness and safety in the treatment of radiation-induced hemorrhagic GDVE.

[Resonance response of cell-tissue structures to impulse frequency of infrared laser radiation of low intensity (experimental study)]. / Rezonansnyi otvet kletochno-tkanevykh struktur na chastotu impul'sov infrakrasnogo lazernogo izlucheniia nizkoi intensivnosti (éksperimental'noe issledovanie).

A morphological evaluation of the results of transcutaneous radiation of male mice with infra-red impulse laser beam for 10 min (10,100, 1000, 10,000 Hz) 5 min, 3 and 24 hours after the procedure has confirmed the existence of "resonance" frequencies for different types of endocrine cells and has shown that the response depends not only on the dose of infrared low-intensity laser radiation. Thus, account for resonance frequencies is one of perspective approaches to optimization of laser therapy which may raise effectiveness and safety of laser exposure.

Pathologic effects of fractionated fast neutrons or photons on the pancreas, pylorus and duodenum of dogs.

Thirty-nine adult male Beagles received either fast neutron or photon irradiation to the right thorax to determine the relative biological effectiveness (RBE) of fast neutrons on normal pulmonary tissue. The right anterior abdomen was included in the field of radiation. Twenty-four dogs (six/group) received fast neutrons with an average energy of 15 MeV to total doses of 1000, 1500, 2250 or 3375 rad in four fractions per week for six weeks. Fifteen dogs received 3000, 4500 or 6750 rad of photons (five/group) in an identical fractionation pattern. All neutron irradiated dogs receiving 3375 and 2250 rad and one receiving 1500 rad developed clinical signs of pancreatic, hepatic and gastrointestinal disturbances. The liver enzymes of these dogs became elevated and they died or were euthanatized in extremis 47-367 days after irradiation. Only one 6750 rad photon dog developed similar signs and died 708 days post-irradiation. Five neutron and 10 photon exposed dogs died of other causes. Neutron-induced lesions in the stomach and duodenum included hemorrhages, erosions, ulcerations and fibrosis. Ulcers perforated the GI tract of five dogs. Pancreatic lesions included degranulation and necrosis of acinar cells, fibrosis ans atrophy. Islet cells were not obviously damaged. All lesions were associated with degenerative and occlusive vascular changes. The RBE of fast neutrons, assessed by clinical signs, gross and microscopic pathology, is approximately 3-4.5 for pancreas and about 4.5 for pylorus and duodenum.

Effect of X-ray irradiation on pepsinogen and on induction of intestinal-type crypts in the pyloric mucosa of the Wistar rat stomach.

The effects of X-ray irradiation on the content and isozyme pattern of pepsinogen and on the induction of intestinal-type crypts in the pyloric mucosa of rat stomach were compared with the previously reported effects of chemical carcinogens, N-methyl-N'-nitro-N-nitrosoguanidine, N-ethyl-N'-nitro-N-nitrosoguanidine and N-propyl-N'-nitro-N-nitrosoguanidine. The gastric regions of 6-week-old male Wistar rats were irradiated with X-rays (1,000 rad) twice at an interval of 3 days. A decrease in pepsinogen content in the pyloric mucosa was observed between 2 and 52 weeks after the irradiation, as had been found in the previous experiments using chemical stomach carcinogens. However, in contrast to the latter experiment, in which the isozyme pattern was altered, the pepsinogen isozyme pattern did not change throughout the observation period after irradiation. Morphologically, intestinal-type crypts appeared and increased gradually after irradiation as after the administration of chemical stomach carcinogens. However, Paneth cells were either not observed or only rarely observed in rats treated with carcinogens, whereas they were found in crypts in the stomachs of the irradiated rats.