Development of branchial ionocytes in embryonic and larval stages of cloudy catshark, Scyliorhinus torazame.

In teleost fish, branchial ionocytes are important sites for osmoregulation and acid-base regulation by maintaining ionic balance in the body fluid. During the early developmental stages before the formation of the gills, teleost ionocytes are localized in the yolk-sac membrane and body skin. By comparing with teleost fish, much less is known about ionocytes in developing embryos of elasmobranch fish. The present study investigated the development of ionocytes in the embryo and larva of cloudy catshark, Scyliorhinus torazame. We first observed ionocyte distribution by immunohistochemical staining with anti-Na+/K+-ATPase (NKA) and anti-vacuolar-type H+-ATPase (V-ATPase) antibodies. The NKA- and V-ATPase-rich ionocytes appeared as single cells in the gill filaments from stage 31, the stage of pre-hatching, while the ionocytes on the body skin and yolk-sac membrane were also observed. From stage 32, in addition to single ionocytes on the gill filaments, some outstanding follicular structures of NKA-immunoreactive cells were developed to fill the inter-filament region of the gill septa. The follicular ionocytes possess NKA in the basolateral membrane and Na+/H+ exchanger 3 in the apical membrane, indicating that they are involved in acid-base regulation like single NKA-rich ionocytes. Three-dimensional analysis and whole-mount immunohistochemistry revealed that the distribution of follicular ionocytes was limited to the rostral side of gill septum. The rostral sides of gill septum might be exposed to faster water flow than caudal side because the gills of sharks gently curved backward. This dissymmetric distribution of follicular ionocytes is considered to facilitate efficient body-fluid homeostasis of catshark embryo.

Phylogenetic and functional properties of hagfish neurohypophysial hormone receptors distinct from their jawed vertebrate counterparts.

Vertebrate neurohypophysial hormones, i.e., vasopressin- and oxytocin-family peptides, exert versatile physiological actions via distinct G protein-coupled receptors. The neurohypophysial hormone receptor (NHR) family was classically categorized into four subtypes (V1aR, V1bR, V2R and OTR), while recent studies have identified seven subtypes (V1aR, V1bR, V2aR, V2bR, V2cR, V2dR and OTR; V2aR corresponds to the conventional V2R). The vertebrate NHR family were diversified via multiple gene duplication events at different scales. Despite intensive research effort in non-osteichthyes vertebrates such as cartilaginous fish and lamprey, the molecular phylogeny of the NHR family has not been fully understood. In the present study, we focused on the inshore hagfish (Eptatretus burgeri), another group of cyclostomes, and Arctic lamprey (Lethenteron camtschaticum) for comparison. Two putative NHR homologs, which were previously identified only in silico, were cloned from the hagfish and designated as ebV1R and ebV2R. In vitro, ebV1R, as well as two out of five Arctic lamprey NHRs, increased intracellular Ca2+ in response to exogenous neurohypophysial hormones. None of the examined cyclostome NHRs altered intracellular cAMP levels. Transcripts of ebV1R were detected in multiple tissues including the brain and gill, with intense hybridization signals in the hypothalamus and adenohypophysis, while ebV2R was predominantly expressed in the systemic heart. Similarly, Arctic lamprey NHRs showed distinct expression patterns, underscoring the multifunctionality of VT in the cyclostomes as in the gnathostomes. These results and exhaustive gene synteny comparisons provide new insights into the molecular and functional evolution of the neurohypophysial hormone system in vertebrates.

Long-term monitoring of egg-laying cycle using ultrasonography reveals the reproductive dynamics of circulating sex steroids in an oviparous catshark, Scyliorhinus torazame.

The many diverse reproductive strategies of elasmobranchs (sharks, skates and rays) from lecithotrophic oviparity to matrotrophic viviparity have attracted significant research attention. However, the endocrine control of elasmobranch reproduction is less well-documented largely due to their reproductive characteristics, such as a long reproductive cycle, and/or repeated internal fertilization using stored sperm in oviparous species. In the present study, for the first time, we succeeded in non-invasive monitoring of the continuing egg-laying cycle of the cloudy catshark Scyliorhinus torazame using portable ultrasound devices. Furthermore, long-term simultaneous monitoring of the egg-laying cycle and measurement of plasma sex steroids revealed cycling patterns of estradiol-17ß (E2), testosterone (T) and progesterone (P4). In particular, a decline in T followed by a reciprocal surge in plasma P4 were consistently observed prior to the appearance of the capsulated eggs, implying that P4 is likely associated with the ovulation and/or egg-case formation. While the cycling pattern of E2 was not as apparent as those of T and P4, threshold levels of E2 (>5 ng/mL) and T (>1 ng/mL) appeared to be crucial in the continuation of egg-laying cycle. The possibility to trace the dynamics of plasma sex steroids in a single individual throughout the reproductive cycles makes the catshark a useful model for regulatory and mechanistic studies of elasmobranch reproduction.

Fulminant myocarditis after the second dose of COVID-19 mRNA vaccination.

Myocarditis is an adverse event associated with coronavirus disease 2019 (COVID-19) mRNA vaccination. A 50-year-old man presented with dyspnea and resting chest pain after receiving the second dose of the COVID-19 mRNA vaccine and developed cardiogenic shock. Fulminant myocarditis was diagnosed by endomyocardial biopsy and treated with intravenous corticosteroids.

N-terminal domain regulates steroid activation of elephant shark glucocorticoid and mineralocorticoid receptors.

Orthologs of human glucocorticoid receptor (GR) and human mineralocorticoid receptor (MR) first appear in cartilaginous fishes. Subsequently, the MR and GR diverged to respond to different steroids: the MR to aldosterone and the GR to cortisol and corticosterone. We report that cortisol, corticosterone and aldosterone activate full-length elephant shark GR, and progesterone, which activates elephant shark MR, does not activate elephant shark GR. However, progesterone inhibits steroid binding to elephant shark GR, but not to human GR. Together, this indicates partial functional divergence of elephant shark GR from the MR. Deletion of the N-terminal domain (NTD) from elephant shark GR (truncated GR) reduced the response to corticosteroids, while truncated and full-length elephant shark MR had similar responses to corticosteroids. Swapping of NTDs of elephant shark GR and MR yielded an elephant shark MR chimera with full-length GR-like increased activation by corticosteroids and progesterone compared to full-length elephant shark MR. Elephant shark MR NTD fused to GR DBD + LBD had similar activation as full-length MR, indicating that the MR NTD lacked GR-like NTD activity. We propose that NTD activation of human GR evolved early in GR divergence from the MR.

Transcriptional activation of elephant shark mineralocorticoid receptor by corticosteroids, progesterone, and spironolactone.

The mineralocorticoid receptor (MR) is a nuclear receptor and part of a large and diverse family of transcription factors that also includes receptors for glucocorticoids, progesterone, androgens, and estrogens. The corticosteroid aldosterone is the physiological activator of the MR in humans and other terrestrial vertebrates; however, its activator is not known in cartilaginous fish, the oldest group of extant jawed vertebrates. Here, we analyzed the ability of corticosteroids and progesterone to activate the full-length MR from the elephant shark (Callorhinchus milii). On the basis of their measured activities, aldosterone, cortisol, 11-deoxycorticosterone, corticosterone, 11-deoxcortisol, progesterone, and 19-norprogesterone are potential physiological mineralocorticoids. However, aldosterone, the physiological mineralocorticoid in humans and other terrestrial vertebrates, is not found in cartilaginous or ray-finned fish. Although progesterone activates MRs in ray-finned fish, progesterone does not activate MRs in humans, amphibians, or alligator, suggesting that during the transition to terrestrial vertebrates, progesterone lost the ability to activate the MR. Both elephant shark MR and human MR are expressed in the brain, heart, ovary, testis, and other nonepithelial tissues, suggesting that MR expression in diverse tissues evolved in the common ancestor of jawed vertebrates. Our data suggest that 19-norprogesterone- and progesterone-activated MR may have unappreciated functions in reproductive physiology.

Comprehensive analysis of genes contributing to euryhalinity in the bull shark, Carcharhinus leucas; Na+-Cl- co-transporter is one of the key renal factors upregulated in acclimation to low-salinity environment.

Most cartilaginous fishes live principally in seawater (SW) environments, but a limited number of species including the bull shark, Carcharhinus leucas, inhabit both SW and freshwater (FW) environments during their life cycle. Euryhaline elasmobranchs maintain high internal urea and ion levels even in FW environments, but little is known about the osmoregulatory mechanisms that enable them to maintain internal homeostasis in hypoosmotic environments. In the present study, we focused on the kidney because this is the only organ that can excrete excess water from the body in a hypoosmotic environment. We conducted a transfer experiment of bull sharks from SW to FW and performed differential gene expression analysis between the two conditions using RNA-sequencing. A search for genes upregulated in the FW-acclimated bull shark kidney indicated that the expression of the Na+-Cl- cotransporter (NCC; Slc12a3) was 10 times higher in the FW-acclimated sharks compared with that in SW sharks. In the kidney, apically located NCC was observed in the late distal tubule and in the anterior half of the collecting tubule, where basolateral Na+/K+-ATPase was also expressed, implying that these segments contribute to NaCl reabsorption from the filtrate for diluting the urine. This expression pattern was not observed in the houndshark, Triakis scyllium, which had been transferred to 30% SW; this species cannot survive in FW environments. The salinity transfer experiment combined with a comprehensive gene screening approach demonstrates that NCC is a key renal protein that contributes to the remarkable euryhaline ability of the bull shark.

Prospective histological evaluation of a 20G core trap with a forward-cutting bevel needle for EUS-FNA of pancreatic lesions.

BACKGROUND: Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) has been established as a method to obtain tissues of various organs. To obtain sufficient tissue has clinical impact to facilitate the diagnosis by clinical pathologists, the assessment and subtyping of various neoplasms, and for further immunohistochemical investigations of tumor type. Recently, a novel 20G core trap with a forward-cutting beveled FNA needle (ProC-F) has become available. The aim of this prospective study was to evaluate the feasibility and diagnostic yield of EUS-FNA for pancreatic lesions using this needle. PATIENTS AND METHOD: In this study, the first puncture was performed using the ProC-F. Only tissue obtained with the first puncture using the ProC-F was used to evaluate diagnostic yield of ProC-F. The second puncture was performed using a 22G standard FNA needle using the same technique as for the first puncture. Second puncture was performed if the endosonographer did not feel that sufficient tissue had not been obtained by first puncture. RESULTS: Fifty-three consecutive patients who underwent EUS-FNA for pancreatic lesions were prospectively enrolled. The technical success rate of EUS-FNA using the ProC-F was 98.1% (52/53). The rate of adequate tissue obtained by ProC-F was 96.2% (50/52). On the other hand, the rate of adequate tissue obtained by the standard needle was 71.1%. The sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy of the ProC-F and the standard needle were 92.5, 100, 100, 76.9, and 94.0%, and 85.2, 100, 100, 55.6, and 87.5%, respectively. Diagnostic yield of ProC-F about sensitivity (P = 0.027), NPV (P = 0.035), and accuracy (P = 0.004) was significantly higher than of standard needle. Adverse events were not seen in any patients. CONCLUSIONS: Although only tissue obtained by the first puncture was evaluated, the rate of adequate tissue and the histologic diagnostic yield for pancreatic lesions were extremely high using the ProC-F.

Electrohydraulic Lithotripsy for Difficult Bile Duct Stones under Endoscopic Retrograde Cholangiopancreatography and Peroral Transluminal Cholangioscopy Guidance.

Background/Aims: Electrohydraulic lithotripsy (EHL) under endoscopic retrograde cholangiopancreatography (ERCP) guidance can be an option to treat difficult stones. Recently, a digital, single-operator cholangioscope (SPY-DS) has become available. Peroral transluminal cholangioscopy (PTLC) using SPY-DS has also been reported. In this retrospective study, the technical feasibility and clinical effectiveness of EHL for difficult bile duct stones under ERCP guidance and under PTLC guidance was examined. Methods: In this pilot study, patients with difficult bile duct stones between July 2016 and July 2017 were retrospectively enrolled. Results: Forty-two consecutive patients underwent EHL using a SPY-DS; 34 patients underwent EHL under ERCP guidance, and the other 8 patients underwent EHL under PTLC guidance. Median procedure time was 31 minutes (range, 19 to 66 minutes). The median number of EHL sessions was 1 (range, 1 to 2), and that of ERCP sessions was also 1 (range, 1 to 3). The rate of complete stone clearance was 98% (41/42). Adverse events such as cholangitis and acute pancreatitis were seen in 14% (6/42), which could be treated conservatively. Conclusions: EHL using SPY-DS was technically feasible, not only under ERCP guidance, but also PTLC guidance. A prospective clinical study of EHL using SPY-DS is needed.

Prospective evaluation of digital single-operator cholangioscope for diagnostic and therapeutic procedures (with videos).

BACKGROUND AND AIM: Recently, the digital single-operator cholangioscope (SPY-DS) has become available. This system may allow diagnosis by direct visualization and allow performance of various therapeutic procedures. The aim of the present study was to prospectively evaluate the clinical utility of DSOCS for diagnostic and therapeutic procedures for biliary disease. METHODS: Technical success was defined as successful visualization of target lesions in the biliary tract and carrying out forceps biopsy as a diagnostic procedure, and successfully carrying out treatment such as guidewire insertion for the area of interest, electrohydraulic lithotripsy (EHL), or migrated stent removal. Also, the present study aimed at investigating diagnostic yield of the cholangioscopic findings and biopsy specimens. RESULTS: A total of 55 consecutive patients were prospectively enrolled in this study; a diagnostic procedure was done in 33 patients, and a therapeutic procedure was done in 22 patients. Overall accuracy of visual findings was 93%, with a sensitivity of 83%, a specificity of 89%, positive predictive value (PPV) of 83%, and negative predictive value (NPV) of 100%. However, the overall accuracy of forceps biopsy was 89%, with a sensitivity, specificity, and PPV of 100%, and NPV of 90%. Overall technical success rate of therapeutic procedures such as selective guidewire insertion, EHL or migrated stent removal was 91% (20/22). Finally, adverse events were seen in two cases in the diagnostic group, but were not seen in the therapeutic group. CONCLUSION: Although additional cases and a randomized, controlled study with another cholangioscope are needed, diagnostic and therapeutic procedures using SPY-DS appear to be feasible and safe.

Evaluation of the safety of endoscopic radiofrequency ablation for malignant biliary stricture using a digital peroral cholangioscope (with videos).

BACKGROUND AND AIM: The clinical impact of catheter-based radiofrequency ablation (RFA) under endoscopic retrograde cholangiopancreatography (ERCP) guidance has recently been reported; however, severe adverse events have also been noted. If tumor is not present in the biliary tract, severe adverse events such as perforation or bleeding as a result of vessel injury around the biliary tract may occur. In addition, the effectiveness of RFA may not be sufficient based solely on radiographic guidance. The aim of the present study was to evaluate the actual feasibility of intraductal RFA by peroral cholangioscope (POCS) evaluation before/after RFA. METHODS: In this retrospective study carried out between July and September 2016, consecutive patients who underwent RFA for malignant biliary stricture and POCS evaluation before/after RFA were enrolled. Primary endpoint of this study was technical feasibility of RFA, which was evaluated by POCS. Secondary endpoints were rates and types of adverse event. RESULTS: A total of 12 consecutive patients were retrospectively enrolled in this study. Stent placement using uncovered metal stents had been previously done in six patients before RFA. Tumor was seen in the biliary tract in all patients. RFA was technically successful in all patients, and clinical success was confirmed in all patients by POCS imaging. Adverse events were seen in only one patient. Median stent patency was 154 days. CONCLUSIONS: RFA for malignant biliary stricture may be safe. To confirm the feasibility and efficacy of RFA, additional cases, prospective studies, and a comparison study between with and without endobiliary RFA are needed.

Prospective clinical study of endoscopic ultrasound-guided biliary drainage using novel balloon catheter (with video).

BACKGROUND AND AIM: On endoscopic ultrasound (EUS)-guided biliary drainage, fistula dilation may be accompanied by leakage of bile juice, potentially along with bacteria or air, so this procedure should be kept as simple and short as possible. To date, various techniques to dilate the fistula have been reported. This prospective, single-center, single-arm study evaluated the technical feasibility and safety of EUS-guided biliary drainage using novel balloon catheters. METHODS: Tip of novel balloon catheters is only 3 Fr and tapered, and the catheters also show favorable push ability. First, biliary tract was punctured using 19-G fine needle aspiration needle. Next, we immediately inserted the novel balloon catheter, and the biliary tract and intestinal wall were dilated. Then, we performed metallic stent placement without any dilation fistula. RESULTS: A total of 20 patients were prospectively enrolled in this study. Technical success rate was 100%. Eleven patients underwent EUS-guided choledochoduodenostomy, and nine patients underwent EUS-guided hepaticogastrostomy. Median procedure time was only 11 min (range, 8-16 min) for EUS-guided choledochoduodenostomy and 14 min (range, 11-18 min) for EUS-guided hepaticogastrostomy. Adverse events were seen in 15% (3/20; self-limited abdominal pain n = 2, peritonitis n = 1). CONCLUSIONS: Although additional cases and a randomized controlled comparison with another dilation technique such as the graded dilation or cystotome dilation technique are needed, our technique may be helpful for EUS-guided biliary drainage.

Clinical utility of endoscopic ultrasound-guided biliary drainage as a rescue of re-intervention procedure for high-grade hilar stricture.

BACKGROUND AND AIM: Re-intervention after stent placement for malignant hepatic hilum obstruction (HBO) is challenging. endoscopic ultrasound-guided biliary drainage (EUS-BD) has been developed as an alternative method for failed endoscopic retrograde cholangiopancreatography (ERCP). In this retrospective study, the clinical utility of EUS-BD as a rescue drainage technique for HBO patients who failed re-intervention under ERCP guidance was evaluated. METHODS: Between April 2012 and August 2015, patients with HBO were enrolled. Patients' characteristics, kinds of metallic stents, configuration of stent placement, overall survival, stent patency, and results of re-intervention were reviewed, along with the re-intervention technical success rate. RESULTS: The biliary stricture type was Bismuth type IV in 59% (23/39) and types IIIa and b in 20.5% (8/39) each. Biliary metallic stent placement was bilateral in 38.5% (15/39), and unilateral in 61.5% (24/39). Primary stent dysfunction was observed in 71.8% (28/39) of cases. Planned re-intervention under ERCP guidance was attempted in 26 patients. The technical success rate was 62% (16/26). For the 10 patients who failed re-intervention under ERCP guidance, EUS-BD was planned. The technical success rate was 100% (10/10). The procedure time was 25.8 min. Adverse events were not seen in any patients. Stent patency after re-intervention was not significantly different between ERCP (165 days) guidance and EUS-BD (152 days) guidance (P = 0.463) CONCLUSIONS: In conclusion, EUS-BD as a re-intervention method for metallic stent obstruction was safe and feasible. If ERCP was failed, EUS-BD may be one of option as re-intervention method for high-grade hilar stricture.

Early detection of nonperitoneal recurrence may contribute to survival benefit after curative gastrectomy for gastric cancer.

BACKGROUND: There is no evidence that strict follow-up using cross-sectional imaging after curative gastrectomy benefits survival; however, nonperitoneal recurrence detected early might be treated with additional surgery. The present study examined whether early detection of recurrence by imaging modalities could increase survival, particularly in patients with nonperitoneal recurrence. METHODS: We retrospectively analyzed 218 patients with recurrent gastric cancer after curative gastrectomy performed from 2002 to 2014. The patients were divided into an asymptomatic group (n = 117) and a symptomatic group (n = 101), according to the presence of symptoms at the time of recurrence, to compare clinicopathological characteristics and long-term survival. RESULTS: Peritoneal recurrence was less frequent in the asymptomatic group (22.2%) than in the symptomatic group (62.4%), the median time to recurrence was shorter (12.7 months vs 18.9 months; P < 0.001), and the median survival time after recurrence was longer (18.7 months vs 7.5 months; P < 0.001). In the asymptomatic group, 10 of 117 patients (8.5%) received additional curative surgery after recurrence. Median overall survival after gastrectomy was not significantly different between the groups (30.1 months for the asymptomatic group vs 30.0 months for the symptomatic group; P = 0.132); however, it was significantly longer among asymptomatic patients with nonperitoneal recurrence compared with symptomatic patients (35.9 months vs 24.0 months; P = 0.039). CONCLUSIONS: The presence of symptoms at recurrence did not affect survival in patients with recurrent gastric cancer. However, detection of nonperitoneal recurrence before the appearance of symptoms may provide survival benefit. Therefore, regular follow-up, including use of imaging modalities, is recommended.

Risk factors for complications after pharyngolaryngectomy with total esophagectomy.

BACKGROUND: Pharyngolaryngectomy with total esophagectomy (PLTE) is an effective surgical treatment for synchronous or metachronous hypopharyngeal or laryngeal cancer and thoracic esophageal cancer, although it is more invasive than esophagectomy and total pharyngolaryngectomy. The aim of this study was to identify risk factors for complications after PLTE. METHODS: From November 2002 to December 2014, a total of 8 patients underwent PLTE at the Shizuoka Cancer Center Hospital, Shizuoka, Japan. We investigated the clinicopathological characteristics, surgical procedures, and postoperative complications of these patients. RESULTS: Of the 8 patients, 5 underwent one-stage PLTE and 3 underwent staged PLTE. There was no mortality in this study. Two cases of tracheal necrosis, two of anastomotic leakage, and one of ileus were observed as postoperative complications. Two patients who underwent one-stage PLTE with standard mediastinal lymph node dissection developed tracheal necrosis and severe anastomotic leakage. CONCLUSION: One-stage PLTE and standard mediastinal lymph node dissection were identified as the risk factors for severe postoperative complications. Staged PLTE or transhiatal esophagectomy should be considered when PLTE is performed and standard mediastinal lymph node dissection should be avoided when one-stage PLTE is performed with transthoracic esophagectomy.

Technical tips for peroral transluminal cholangioscopy using novel single-operator cholangioscope (with videos).

Endoscopic retrograde cholangiopancreatography (ERCP) is the gold-standard modality for diagnosis and therapy of bilio-pancreatic disease. In particular, peroral cholangiography (POCS) is a useful modality not only for diagnosing biliary disease, but also for therapeutic procedures such as electrohydraulic lithotripsy. The SPY-DS single-operator cholangioscope has recently become available, and offers favorable visualization, a wide view, suction function and a larger accessory working channel. However, if the duodenoscope cannot be advanced into the ampulla of Vater for reasons such as surgical anatomy, POCS cannot be performed. On the other hand, percutaneous transhepatic cholangiodrainage (PTCD) has been developed as an alternative endoscopic ultrasound-guided approach to the biliary tract. Peroral transluminal cholangioscopy (PTLC) using SPY-DS is a novel approach. Because transluminal interventional procedures under endoscopic ultrasound guidance have recently been developed, our technique may have clinical impact for selected cases.

Choledochoduodenal Fistula after the Placement of a Partially Covered Metal Stent for Unresectable Pancreatic Cancer.

A 75-year-old Japanese man with type 2 diabetes mellitus suffered from unresectable pancreatic head cancer and was admitted to our institution due to acute cholangitis. A partially covered metal stent was placed at that time. 11 months later, he was readmitted for acute cholangitis. Upper endoscopy revealed complete stent distal migration and a small hole on the oral side of the ampulla. While attempting cannulation into the hole, an upstream biliary tract was revealed. Accordingly, we diagnosed the patient to have a choledochoduodenal fistula. After metal stent removal and balloon dilation, we placed two 7 Fr plastic stents, which successfully relieved the patient's cholangitis.