Search

In recent years, blooms of toxic Alexandrium ostenfeldii strains have been reported from around the world. In 2013, the species formed a red tide in a shallow lagoon in western Japan, which was the first report of the species in the area. To investigate the genetic relatedness of Japanese A. ostenfeldii and global isolates, the full-length SSU, ITS and LSU sequences were determined, and phylogenetic analyses were conducted for isolates from western and northern Japan and from the Baltic Sea. Genotyping and microsatellite sequence comparison were performed to estimate the divergence and connectivity between the populations from western Japan and the Baltic Sea. In all phylogenetic analyses, the isolates from western Japan grouped together with global isolates from shallow and low saline areas, such as the Baltic Sea, estuaries on the east coast of U.S.A. and from the Bohai Sea, China. In contrast, the isolates from northern Japan formed a well-supported separate group in the ITS and LSU phylogenies, indicating differentiation between the Japanese populations. This was further supported by the notable differentiation between the sequences of western and northern Japanese isolates, whereas the lowest differentiation was found between the western Japanese and Chinese isolates. Microsatellite genotyping revealed low genetic diversity in the western Japanese population, possibly explained by a recent introduction to the lagoon from where it was detected. The red tide recorded in the shallow lagoon followed notable changes in the salinity of the waterbody and phytoplankton composition, potentially facilitating the bloom of A. ostenfeldii.

The 2011 Great East Japan Earthquake and the subsequent huge tsunami greatly affected both human activity and the coastal marine ecosystem along the Pacific coast of Japan. The tsunami also reached Funka Bay in northern Japan and caused serious damage to the scallop cultures there, and this tsunami was believed to have affected the coastal environments in the bay. Therefore, we investigated the changes in the spatial abundance and distribution of the toxic dinoflagellates Alexandrium tamarense cysts before the tsunami (August 2010) and after the tsunami (May 2011, August 2011, May 2012 and August 2012) in the bay. Further, monthly sampling was conducted after the tsunami to identify seasonal changes of Alexandrium catenella/tamarense cysts and vegetative cells. Significant increases were observed in the populations of A. catenella/tamarense cysts, comparing the abundances before the tsunami (in August 2010; 70 ± 61 cysts g −1 wet sediment) to those just after it (in May 2011; 108 ± 84 cysts g −1 wet sediment), and both A. tamarense bloom (a maximum density was 1.3 × 10 3 cells L −1 ) and PSP (Paralytic Shellfish Poisoning) toxin contamination of scallops (9.4 mouse unit g −1 was recorded) occurred in the bay. Seasonal sampling also revealed that the encystment of A. tamarense and the supply of the cysts to bottom sediments did not occur in the bay from September to April. These results strongly suggested that the mixing of the bottom sediments by the tsunami caused the accumulation of the toxic A. tamarense cysts in the surface of bottom sediment through the process of redeposition in Funka Bay. Moreover, this cyst deposition may have contributed to the toxic bloom formation as a seed population in the spring of 2011.

Aim Congenital tracheal stenosis is an obstructive airway lesion that often presents as a life-threatening emergency. We had introduced the balloon dilatation and placement of the expandable metallic airway stent as a therapeutic option, and this study aimed to clarify the long-term outcomes in pediatric patients. Methods A retrospective review of five infants in whom balloon expandable metallic airway stents (10–40mm long and 6–8mm in diameter) were inserted in 1997 to 2000 was conducted. Results There was an immediate improvement of respiratory obstruction in all five infants (aged 7days to 12months) with four weaned from ventilation. One child died after 9months of palliative treatment. In all inflammation and granulation tissue developed over the stents, but this could be managed by scraping or balloon compression. Metallic stents have been in place a mean of 12years (range 6months to 13years) after insertion without other complications. Four children are alive and well with their stents in place. Recently, an attempt to remove the stent was done in two patients who showed dyspnea on exertion. They underwent tracheoplasty following successful complete removal of metallic stent using cardiopulmonary bypass. Conclusion Use of expandable metallic airway stents following balloon dilatation can be left for long periods to relieve tracheal obstruction. Development of granulation tissue is a major treatable complication. Removal of the stent was safely completed by open surgical intervention using a cardiopulmonary bypass. The airway stent may provide an important therapeutic option in selected cases with congenital tracheal stenosis.

Intrapericardial extralobar pulmonary sequestration is a very rare congenital lung anomaly. We report a case of this condition, detected as an intrathoracic cystic lesion by using prenatal ultrasonography. The neonate was born at 38 weeks of gestation with no progression of the lesion and no respiratory or cardiac symptoms. Ultrasonography and computed tomography (CT) revealed a 40 × 17 × 17-mm intrapericardial lesion, composed of cystic components and a solid component. Intrapericardial extrapulmonary sequestration was suspected largely because CT showed a vague aberrant artery. At the age of 3 months, elective surgery was performed, and the postoperative course was uneventful.

Quantification of diarrhetic shellfish poisoning (DSP) toxins (okadaic acid analogues), and other lipophilic toxins in single-cell isolates of the dinoflagellates Dinophysis fortii, D. acuminata, D. mitra, D. norvegica, D. tripos, D. infundibulus and D. rotundata, collected in coastal waters Hokkaido, Japan in 2005, was carried out by liquid chromatography–tandem mass spectrometry (LC–MS/MS). Okadaic acid (OA), dinophysistoxin-1 (DTX1), 7-O-palmitoyldinophysistoxin-1 (DTX3), pectenotoxin-1 (PTX1), pectenotoxin-11 (PTX11), pectenotoxin-2 (PTX2), pectenotoxin-6 (PTX6), pectenotoxin-2 seco-acid (PTX2sa), yessotoxin (YTX) and 45-hydroxyyessotoxin (45-OHYTX) were quantified by LC–MS/MS. PTX2 was the dominant toxin in D. acuminata, D. norvegica and D. infundibulus whereas both DTX1 and PTX2 were the principal toxins in D. fortii. None of the toxins were detected in D. mitra, D. rotundata and D. tripos. These results suggest that D. fortii is the most important species responsible for DSP contamination of bivalves in Hokkaido. This is the first finding of PTX2 in D. infundibulus, and confirms the presence of PTX2 in Japanese D. acuminata and D. norvegica collected from natural seawater.