Overview of research on tuna thermo-physiology using electric tags

The behavioral physiology of bigeye tuna was investigated using acoustic tags in the 1990s. They spend most of the daylight hours below the thermocline but make regular brief excursions into the mixed layer. In doing so, they reduce the efficacy of their vascular countercurrent heat exchangers while gaining heat from the warmer environment and then increase it again when they return below the thermocline. Recently, archival tags have been used on a range of tuna species including bluefin. This tag, recovered when the tuna is harvested, yields time-series data over longer periods than acoustic tags. Although immature Pacific bluefin spend most of their time at the surface, they often dive below the thermocline, maintaining a peritoneal temperature. This might be due either to heat conservation or high heat production. Further, while giant Atlantic bluefin show an ability to maintain their temperature above the ambient, there are occasions in cold water when some physiological process is clearly limiting their dive time. Solution of the growth conundrum that their warm body temperature may pose an ecological problem as they grow in body mass, should be clarified by using tag data. This will lead to investigation of their adaptation mechanisms to their habitats

Forecasting the stock size of the autumn cohort of Japanese common squid (Todarodes pacificus) based on the abundance of trawl-caught juveniles

The distribution of juveniles of Japanese common squid (Todarodes pacificus) autumn cohort and its relation to oceanographic conditions were analyzed to see if they can be used to accurately forecast the stock size. Research cruises was conducted using a total of 5 research vessels during 2001-2010 in April in the southern Sea of Japan. Juveniles were caught in 267 of 331 tows of a trawl net at approximately 0-10 m depth, and the numbers caught in each tow ranged from 0 to 1087. Samples were divided into the autumn and winter cohorts based on the dorsal mantle length (DML). The autumn cohort was abundant (40 inds / tow) where the sea surface temperature ranged from 10 to 11 °C and less abundant in warmer water. This cohort was more abundant in offshore areas, while the winter cohort was more abundant near shore. The mean catch of the autumn cohort was used as an index of the annual abundance of juveniles. This index and the stock size were significantly correlated. These results suggest that the stock size of the T. pacificus autumn cohort can be forecasted before the fishing season based on the abundance of juveniles, but this relationship is highly uncertain due to observational error

Diving patterns and performance of Pacific bluefin tuna (Thunnus thynnus orientalis) as recorded by archival tags

Archival tagged immature Pacific bluefin tuna were released off Tsushima Island in the East China Sea. Time-series data on swimming depth, ambient temperature, internal body temperature, and light intensity were recorded every 128s to evaluate : 1) their vertical swimming patterns to depths below the thermocline and 2) the development of their diving performance with growth. In summer, the tuna spent most of their time at the surface, but occasionally dove to depths below the thermocline during the daytime, and at dawn and dusk. In addition, bluefin dove at increasing descent rates and surfaced more slowly when they made excursions to deeper depths. Larger-sized bluefin dove to much deeper depths than smaller individuals, suggesting that the diving performance of bluefin is related to their body size and larger size enables them to expand their vertical movement range

Simple and Sensitive Enzyme-Linked Immunosorbent Assay for Ivermectin

A sensitive and reproducible enzyme-linked immunosorbent assay (ELISA) for the determination of the concentration of ivermectin (IVM) in biological fluids was developed. A conjugate of IVM on bovine serum albumin and poly-L-lysine was used to produce antibodies in rabbits and served as a solid-phase marker for titration of antibodies, respectively. The competitive ELISA was conducted by simultaneously incubating IVM and IVM-biotin conjugate with anti-IVM antiserum over goat anti-rabbit IgG (Fc) and then determining the amount of bound IVM-biotin with avidin-peroxidase conjugate as a tracer. The coefficient of variation for the assay was less than 10% in the range of 0.3?10 ng/ml. The limit of detection was 0.1 ng/ml. The cross-reactivities of anti-IVM antiserum with some anthelmintic drugs were negligible. Using this ELISA, serum levels of IVM were easily determined in Mongolian jirds (Meriones unguiculatus) up to 72 hr following a single oral dose of 500 μg/kg of body weight

Ochratoxin A, citrinin and deoxynivalenol decrease claudin-2 expression in mouse rectum CMT93-II cells.

Intestinal epithelial cells are the first targets of ingested mycotoxins, such as ochratoxin A, citrinin and deoxynivalenol. It has been reported that paracellular permeability regulated by tight junctions is modulated by several mycotoxins by reducing the expression of specific claudins and integral membrane proteins in cell-cell contacts, accompanied by increase in phosphorylation of mitogen-activated protein kinases, including extracellular signal-related kinase (ERK) 1/2, p38 and c-Jun NH2-terminal protein kinase. Claudin-2 is expressed in the deep crypt cells, but not in the villus/surface cells in vivo. While Caco-2, T84 and IPEC-J2 cells, which are widely used intestinal epithelial cell lines to assess the influence of mycotoxins, do not express claudin-2, CMT93-II cells express claudin-2. We previously reported that inhibition of the ERK pathway reduced claudin-2 levels in cell-cell contacts in CMT93-II cells. In this study, we examined whether ochratoxin A, citrinin and deoxynivalenol affect claudin-2 expression and ERK1/2 phosphorylation in CMT93-II cells. We found that all mycotoxins reduced claudin-2 expression in cell-cell contacts, with reduction (by citrinin and deoxynivalenol) or no change (by ochratoxin A) in phosphorylated ERK1/2. All mycotoxins increased transepithelial electrical resistance, but did not affect flux of fluorescein. While ochratoxin A and citrinin are known to be nephrotoxic, only deoxynivalenol reduced claudin-2 expression in MDCK II cells derived from the renal tubule. These results suggest that claudin-2 expression is regulated not only by the ERK pathway, but also by other pathways in an organ-specific manner.福岡歯科大学2017年

Optical and Near-Infrared Photometry of Nova V2362 Cyg : Rebrightening Event and Dust Formation

We present optical and near-infrared (NIR) photometry of a classical nova, V2362 Cyg (= Nova Cygni 2006). V2362 Cyg experienced a peculiar rebrightening with a long duration from 100 to 240 d after the maximum of the nova. Our multicolor observation indicates an emergence of a pseudophotosphere with an effective temperature of 9000 K at the rebrightening maximum. After the rebrightening maximum, the object showed a slow fading homogeneously in all of the used bands for one week. This implies that the fading just after the rebrightening maximum ( less or equal 1 week ) was caused by a slowly shrinking pseudophotosphere. Then, the NIR flux drastically increased, while the optical flux steeply declined. The optical and NIR flux was consistent with blackbody radiation with a temperature of 1500 K during this NIR rising phase. These facts are likely to be explained by dust formation in the nova ejecta. Assuming an optically thin case, we estimate the dust mass of 10^(-8) -- 10^(-10) M_solar, which is less than those in typical dust-forming novae. These results support the senario that a second, long-lasting outflow, which caused the rebrightening, interacted with a fraction of the initial outflow and formed dust grains.Comment: 6 pages, 4 figures, 2010, PASJ, 62, 1103--1108, in pres

Secondary Torsion of Vermiform Appendix with Mucinous Cystadenoma

Torsion of the vermiform appendix is a rare disorder, which causes abdominal symptoms indistinguishable from acute appendicitis. We report a case (a 34-year-old male) of secondary torsion of the vermiform appendix with mucinous cystadenoma. This case was characterized by mild inflammatory responses, pentazocine-resistant abdominal pain, and appendiceal tumor, which was not enhanced by the contrast medium on computed tomography presumably because of reduced blood flow by the torsion. These findings may be helpful for the preoperative diagnosis of secondary appendiceal torsion

The 2006 November outburst of EG Aquarii: the SU UMa nature revealed

We report time-resolved CCD photometry of the cataclysmic variable EG Aquarii during the 2006 November outburst During the outburst, superhumps were unambiguously detected with a mean period of 0.078828(6) days, firstly classifying the object as an SU UMa-type dwarf nova. It also turned out that the outburst contained a precursor. At the end of the precursor, immature profiles of humps were observed. By a phase analysis of these humps, we interpreted the features as superhumps. This is the second example that the superhumps were shown during a precursor. Near the maximum stage of the outburst, we discovered an abrupt shift of the superhump period by ${\sim}$ 0.002 days. After the supermaximum, the superhump period decreased at the rate of $\dot{P}/P$=$-8.2{\times}10^{-5}$, which is typical for SU UMa-type dwarf novae. Although the outburst light curve was characteristic of SU UMa-type dwarf novae, long-term monitoring of the variable shows no outbursts over the past decade. We note on the basic properties of long period and inactive SU UMa-type dwarf novae.Comment: 9 pages, 7 figures, accepted for PAS

Carotid artery stenting via a femoral bypass graft: technical note.

BACKGROUND: We described a case of endoluminal stent placement for a cervical internal carotid artery stenosis in which access was obtained via the femoral bypass graft. CASE DESCRIPTION: A 70-year-old man with known disease of the carotid, peripheral, and coronary arteries as well as congestive heart failure presented for endoluminal revascularization of a severe right internal carotid artery stenosis. Transradial access was complicated by the left subclavian artery occlusion and hypercalcified aortic arch. Bilateral femoral artery was replaced with bypass graft because of atherosclerosis obliterans. An alternative approach was attempted via the exposed left femoral bypass graft. The left inguinal region was incised, and the left common femoral-popliteal bypass graft was exposed. After placement of a purse string suture at the puncture site, the guiding sheath was introduced into the graft and positioned into the right common carotid artery. Stenting was successfully performed, and the suture was tied after withdrawing the sheath. CONCLUSIONS: This novel approach should be considered for endovascular procedures for which access to the carotid artery is limited