Malodour from oral malignant fungating wound: sprayed metronidazole - case report

Metronidazole gel or ointment is recommended for the treatment of malodour from malignant fungating wounds. However, this medication may not settle adequately in oral lesions because its texture causes discomfort and it tends to be washed out by saliva. We report a case of malodour due to an oral lesion that was well controlled with sprayed metronidazole.

Identification of an adverse outcome pathway (AOP) for chemical-induced craniofacial anomalies using the transgenic zebrafish model

Craniofacial anomalies are one of the most frequent birth defects worldwide and are often caused by genetic and environmental factors such as pharmaceuticals and chemical agents. Although identifying adverse outcome pathways (AOPs) is a central issue for evaluating the teratogenicity, the AOP causing craniofacial anomalies has not been identified. Recently, zebrafish has gained interest as an emerging model for predicting teratogenicity because of high throughput, cost-effectiveness and availability of various tools for examining teratogenic mechanisms. Here, we established zebrafish sox10-EGFP reporter lines to visualize cranial neural crest cells (CNCCs) and have identified the AOPs for craniofacial anomalies. When we exposed the transgenic embryos to teratogens that were reported to cause craniofacial anomalies in mammals, CNCC migration and subsequent morphogenesis of the first pharyngeal arch were impaired at 24 hours post-fertilization. We also found that cell proliferation and apoptosis of the migratory CNCCs were disturbed, which would be key events of the AOP. From these results, we propose that our sox10-EGFP reporter lines serve as a valuable model for detecting craniofacial skeletal abnormalities, from early to late developmental stages. Given that the developmental process of CNCCs around this stage is highly conserved between zebrafish and mammals, our findings can be extrapolated to mammalian craniofacial development and thus help in predicting craniofacial anomalies in human.

Systemic Opioids for Dyspnea in Cancer Patients: A Real-world Observational Study

CONTEXT

Although Systemic opioids are recommended as a pharmacological treatment for cancer-related dyspnea, their effectiveness and safety needs to be investigated in a real-world context OBJECTIVES: To evaluate the effectiveness and safety of systemic regular opioids for dyspnea in cancer patients, in the real-world palliative care practice.

METHODS

This was a multicenter prospective observational study. We consecutively enrolled adult cancer patients starting regular opioids (morphine, oxycodone, hydromorphone, or fentanyl) for dyspnea from 12 palliative care services across Japan. We evaluated dyspnea intensity using the Numerical Rating Scale (NRS) and Integrated Palliative Outcome Scale (IPOS) every 24 hours until 72 hours after starting opioids (T1-T3). We also evaluated common opioid-related adverse events (AEs) and other severe AEs.

RESULTS

We enrolled 402 cancer patients. The proportion of responders was 68.8% (95%confidence intervals (CI): 0.63-0.74) at T1, 75.7% (95%CI: 0.70-0.81) at T2, and 82.1% (95%CI: 0.76-0.87) at T3. The mean differences in dyspnea NRS from baseline were 1.73 (95%CI: 1.46-1.99) at T1, 1.99 (95%CI: 1.71-2.28) at T2, and 2.47 (95%CI:2.13-2.82) at T3. The most common treatment-emergent AE was somnolence with an incidence of the severe form of approximately 10% throughout the study period. In the multivariate analysis, baseline dyspnea NRS ≥6 had a positive correlation with dyspnea relief by systemic regular opioids, while liver metastasis, clinician-predicted survival days, and opioid tolerance had a negative correlation.

CONCLUSION

Regular systemic opioids were effective for dyspnea in real-world cancer patients.

Clinical features and progress of ischemic gastritis with high fatalities: Seven case reports

BACKGROUND

Ischemic gastritis is a clinically rare and highly fatal disease that occurs when the hemodynamics of a patient with vascular risk is disrupted. Early diagnosis and treatment are possible only with upper endoscopy after symptom appearance. We report seven cases of ischemic gastritis and its clinical features, prognosis, and indicators that may help in early detection.

CASE SUMMARY

Of the seven patients, six had vascular risk and five died within 2 wk of diagnosis. Their symptoms included hematemesis and hypotension. Although surgery is a choice for radical treatment, not all patients were tolerant. For such patients, conservative treatment was selected, but all of them died. In contrast, patients who underwent repeat endoscopy showed improved mucosal findings, suggesting that this improvement may not affect prognosis. Some ischemic changes such as wall thickening, mural emphysema, and fluid retention in the stomach were observed before diagnosis through endoscopy and computed tomography (CT). The CT scan can be effective for early detection, and improvement in circulatory failure and aggressive treatment may save the lives of patients with this disease.

CONCLUSION

The characteristic CT findings enable early detection of ischemic gastritis. Early diagnosis increases the chance of survival if early therapeutic intervention and improvement of circulatory dynamics can be achieved in this highly fatal disease.

Liver cyst with biliary communication treated with endoscopic ultrasound-guided drainage: A case report

RATIONALE

Simple liver cysts are common, and usually benign and asymptomatic, requiring little to no treatment. Liver cysts with biliary communication, however, are rare and require effective treatment to avoid recurrence.

PATIENT CONCERNS

A 70-year-old woman with breast cancer visited our hospital for treatment. Physical examination revealed abdominal distension and bilateral lower leg edema.

DIAGNOSIS

Abdominal contrast-enhanced computed tomography revealed a giant liver cyst, inducing inferior vena cava compression that was causing her edema.

INTERVENTIONS

Percutaneous transhepatic cyst drainage was performed. Since the bilirubin level in the drained fluid was high, the patient was diagnosed with a liver cyst with biliary communication. After the procedure, her symptoms improved and the cyst decreased in size. However, the drainage volume did not decrease after approximately 2 weeks. Sclerotherapy with minocycline was ineffective. Thus, endoscopic retrograde cholangiopancreatography was performed, and an endoscopic nasobiliary drainage tube was inserted. The percutaneous drainage tube was clamped, and the cyst showed increase in size. Therefore, endoscopic ultrasound-guided cyst drainage, which is less invasive than surgery, was performed.

OUTCOMES

The cyst tended to decrease in size even after the percutaneous drainage tube had been removed. At 3years follow-up, the cyst has almost disappeared.

LESSONS

Endoscopic ultrasound-guided drainage can treat liver cyst with biliary communication.

Direct oral anticoagulants increase bleeding risk after endoscopic sphincterotomy: a retrospective study

Background

Bleeding can be a serious adverse event of endoscopic sphincterotomy (EST). However, the risk of EST bleeding between direct oral anticoagulant (DOAC) users and those who received no antithrombotic agents has not been clarified. This study analyzed the risk factors for bleeding after EST in patients on DOAC and evaluated the Japan Gastroenterological Endoscopy Society (JGES) guidelines for gastroenterological endoscopy in patients undergoing antithrombotic treatment.

Methods

We retrospectively analyzed 524 patients treated with EST who received DOAC or no antithrombotic drug from May 2016 to August 2019. We investigated the risk factors for bleeding. DOAC was typically discontinued for ≤ 1-day based on the JGES guideline. Although DOAC therapy recommenced the next morning after EST in principle, the duration of DOAC cessation and heparin replacement were determined by the attending physician based on each patient’s status.

Results

The number of patients on DOAC (DOAC group) and those not on antithrombotic drug (no-drug group) was 42 (8.0%) and 482 (92.0%), respectively. DOAC was discontinued for ≤ 1-day in 17 (40.0%) patients and for > 1-day in 25 (60.0%). Of the 524 patients, 21 (4.0%) had EST bleeding. The bleeding rate was higher in the DOAC group (14.0%) (p = 0.004). Multivariate analysis showed that bleeding occurred more frequently in patients on DOAC (odds ratio [OR] 3.95, 95% confidence interval [CI] 1.37–11.4, p = 0.011), patients with low platelet counts (< 100,000/µl) (OR 6.74, 95% CI 2.1–21.6, p = 0.001), and elderly patients (> 80 years old) (OR 3.36, 95%CI 1.17–9.65, p = 0.024).

Conclusions

DOAC treatment, low platelet count, and old age (> 80 years old) are risk factors for EST bleeding. Although the bleeding incidence increased in patients on DOAC who received antithrombotic therapy according to the JGES guidelines, successful hemostasis was achieved with endoscopy in all cases, and no thrombotic events occurred after cessation of DOAC. Thus, the JGES guidelines are acceptable.

Effect of Antibiotic Resistance of Pathogens on Initial Antibiotic Therapy for Patients With Cholangitis

Objectives

Considering that pathogens resistant to initial antibiotic therapies for cholangitis can affect mortality rates, appropriate initial empiric antibiotic therapy is important. However, evidence regarding the influence of pathogens resistant to initial antibiotics in patients with cholangitis who have undergone early endoscopic retrograde cholangiopancreatography (ERCP) is limited, and the conditions in several cases can improve with early ERCP even when pathogens resistant to initial antibiotics are detected on time. Therefore, this study aimed to assess the influence of pathogens resistant to initial antibiotics on the course of cholangitis in patients undergoing early ERCP.

Materials and methods

Patients (n=266) with positive blood or bile culture results treated with early ERCP were divided into those with cultures that were resistant to the initial antibiotics (antibiotic-resistant group; n=66; 24.8%) and those with cultures that were sensitive to the initial antibiotics (antibiotic-sensitive group; n=200; 75.2%). The duration of hospitalization, in-hospital mortality rates due to cholangitis, rates of increased disease severity, and complications during hospitalization were studied.

Results

Enterococcus, Enterobacter, Citrobacter, and Pseudomonas species showed high resistance to several antibiotics. No significant between-group differences were found in the duration of hospitalization, in-hospital mortality rates due to cholangitis, and rates of increased disease severity. However, the rate of post-ERCP cholecystitis was significantly higher in the antibiotic-resistant group than in the antibiotic-sensitive group (p=0.0245).

Conclusions

Even if the initial antibiotics were ineffective, the rate of fatal outcomes did not increase among patients with cholangitis who had undergone early ERCP. However, when initial antibiotics were ineffective, the frequency of post-ERCP cholecystitis increased even after early bile duct decompression.

Advanced Colon Cancer after Curative Resection of Intramucosal Adenocarcinoma with Endoscopic Submucosal Dissection

Endoscopic resection, particularly endoscopic submucosal dissection (ESD), for colorectal cancers enables a precise pathological diagnosis and safe R0 resection. The recurrence rate after ESD is generally extremely low, with annual surveillance colonoscopy recommended. However, surveillance may not be considered for super-elderly patients owing to their condition. This is a case report of an 85-year-old man in whom curative resection was achieved for an intramucosal adenocarcinoma with ESD. The patient presented with a hypoechoic mass located in his lower right abdomen, diagnosed via surveillance abdominal ultrasound. He had undergone curative ESD for intramucosal cecal cancer 2 years prior. Colonoscopy revealed a type 2 epithelial tumor at the proximal aspect of the ESD scar. Ileocolic resection with lymph node dissection was performed. An epithelial tumor and well-differentiated adenocarcinoma but not a submucosal tumor was detected in the mucosal layer. The lesion was diagnosed not as a local recurrence after ESD but as a newly emerged original advanced cancer. After ESD for colorectal cancer, a newly developed advanced cancer may occur at the site of the ESD scar in a shorter term than usual. Surveillance colonoscopy after ESD is necessary even for super-elderly patients.

Salvage endovascular embolization of the left pulmonary artery for recurrent pseudoaneurysm

Background

Pulmonary pseudoaneurysm (PPA) is a potentially lethal complication of lung resection with a high risk of recurrence after endovascular coiling.

Case presentation

We report a case in which recurrent hemoptysis due to PPA after left lower lobe sleeve resection was treated by endovascular embolization of the left main pulmonary artery as a salvage treatment. The first hemoptysis was managed by endovascular coil embolization with extracorporeal membrane oxygenation, but refractory hemorrhage occurred 3 months later due to penetration of the endovascular coil into the bronchial anastomosis site. Because left completion pneumonectomy was considered too high risk, the left main pulmonary artery was palliatively embolized using an Amplatzer vascular plug (St. Jude Medical, MN, USA) to totally disrupt the left pulmonary arterial flow.

Conclusions

Total embolization of the left main pulmonary artery for repeated PPA rupture may be useful as a palliative treatment in patients unable to tolerate pneumonectomy.

A Targeted Biopsy during Menstruation for the Definitive Diagnosis of Rectovaginal Endometriosis: A Report of Two Cases

We herein report the definitive diagnosis of rectovaginal endometriosis in two cases. Case 1 involved a 46-year-old woman with abdominal pain and hematochezia. The diagnosis after the first and second examinations using lower gastrointestinal (GI) endoscopy was unclear. Differential diagnoses included mucosa-associated lymphoid tissue and colorectal cancer. The third lower GI endoscopy with a targeted biopsy, performed during menstruation, confirmed rectovaginal endometriosis. Case 2 involved a 38-year-old woman with hematochezia. Lower GI endoscopy during menstruation revealed rectovaginal endometriosis. When rectovaginal or bowel endometriosis is suspected, lower GI endoscopy and a targeted biopsy during menstruation can prevent unnecessary surgery.

Clinical and endoscopic features of aorto-duodenal fistula resulting in its definitive diagnosis: an observational study

Background

Upper gastrointestinal (GI) bleeding is the most important presentation of an aorto-duodenal fistula (ADF). Early diagnosis is difficult, and the disease is associated with high mortality. The present study aimed to examine the clinical and the endoscopic characteristics of ADF in eight patients who presented to our hospital. We also sought to clarify the diagnostic approach towards the disease.

Methods

The present study examined the clinical and the endoscopic/computed tomography (CT) characteristics of ADF in eight patients who were definitively diagnosed with this condition in a 12-year period at our hospital.

Results

The patients comprised of five men and three women, with a mean age of 69.8 years. Upper gastrointestinal bleeding was the chief complaint for all the patients. Out of these, two patients presented with shock. The patients’ mean haemoglobin at presentation was 7.09 g/dL, and the mean number of blood transfusions was 7.5. All patients had undergone intervention to manage an aortic pathology in the past. As the first investigation, an upper GI endoscopy in 5 and a CT scan in 3 patients were performed. In cases where CT scan was performed first, no definitive diagnosis was obtained, and the diagnosis was confirmed by performing an upper GI endoscopy. In cases where endoscopy was performed first, definitive diagnosis was made in only one case, and the other cases were confirmed by the CT scan. In some cases, tip attachments, converting to long endoscopes, and marking clips were found useful.

Conclusions

In patients who have undergone intervention to manage an aortic pathology and have episodes of upper gastrointestinal bleeding, ADF cannot be definitively diagnosed with only one investigation. In addition, when performing upper GI endoscopy in cases where an ADF is suspected, tip attachment, converting to a long endoscope, and using marking clips can be helpful.

Secondary Minimal Change Disease Due to Pancreatic Cancer Improved by Chemotherapy

We herein describe an 82-year-old patient who presented with proteinuria and systemic edema. He was diagnosed with minimal change disease (MCD) and was found to have stage III pancreatic cancer. He could not undergo surgical resection due to invasion to the celiac artery and he was thus treated with chemotherapy. After a month of chemotherapy, his proteinuria improved to a normal level. After two months of chemotherapy, computed tomography indicated a partial response to the therapy. MCD can occur as paraneoplastic syndrome in patients with malignant disease, and chemotherapy can be effective for MCD associated with paraneoplastic syndrome.

Chemical-Induced Cleft Palate Is Caused and Rescued by Pharmacological Modulation of the Canonical Wnt Signaling Pathway in a Zebrafish Model

Cleft palate is one of the most frequent birth defects worldwide. It causes severe problems regarding eating and speaking and requires long-term treatment. Effective prenatal treatment would contribute to reducing the risk of cleft palate. The canonical Wnt signaling pathway is critically involved in palatogenesis, and genetic or chemical disturbance of this signaling pathway leads to cleft palate. Presently, preventative treatment for cleft palate during prenatal development has limited efficacy, but we expect that zebrafish will provide a useful high-throughput chemical screening model for effective prevention. To achieve this, the zebrafish model should recapitulate cleft palate development and its rescue by chemical modulation of the Wnt pathway. Here, we provide proof of concept for a zebrafish chemical screening model. Zebrafish embryos were treated with 12 chemical reagents known to induce cleft palate in mammals, and all 12 chemicals induced cleft palate characterized by decreased proliferation and increased apoptosis of palatal cells. The cleft phenotype was enhanced by combinatorial treatment with Wnt inhibitor and teratogens. Furthermore, the expression of tcf7 and lef1 as a readout of the pathway was decreased. Conversely, cleft palate was prevented by Wnt agonist and the cellular defects were also prevented. In conclusion, we provide evidence that chemical-induced cleft palate is caused by inhibition of the canonical Wnt pathway. Our results indicate that this zebrafish model is promising for chemical screening for prevention of cleft palate as well as modulation of the Wnt pathway as a therapeutic target.

Limb-Based Patency After Surgical vs Endovascular Revascularization in Patients with Chronic Limb-Threatening Ischemia

PURPOSE

To determine whether limb-based patency (LBP) after infrainguinal revascularization for chronic limb-threatening ischemia (CLTI) is similar between bypass surgery and endovascular therapy (EVT).

MATERIALS AND METHODS

The database for the Surgical Reconstruction vs Peripheral Intervention in Patients With Critical Limb Ischemia (SPINACH) study was interrogated to identify 130 patients (mean age 73±8 years; 94 men) who underwent bypass surgery and 271 patients (mean age 74±10 years; 178 men) who underwent EVT alone. Skin perfusion pressure (SPP) and the ankle-brachial index (ABI) were measured before the procedure and at 0, 1, and 3 months after revascularization. The outcome measure was hemodynamically evaluated LBP (SPP ≥10 mm Hg or ABI ≥0.1) maintained over the first 3 months after treatment. Any reintervention or major amputation was regarded as loss of LBP. The associations between the revascularization strategy (bypass vs EVT) and between the preoperative characteristics and the study outcome (ie, SPP- or ABI-based LBP), were determined using generalized linear mixed models with a logit link function. Patency rates are presented with the 95% confidence interval (CI).

RESULTS

The bypass surgery group had a higher stage of limb severity (WIfI) and anatomic complexity (GLASS) than the EVT group, whereas the EVT group had a higher prevalence of heart failure. Both SPP- and ABI-based LBP rates were higher in the bypass group than in the EVT group. SPP-based LBP rates at 3 months were 73.8% (95% CI 63.4% to 84.2%) in the bypass group and 46.2% (95% CI 38.5% to 53.8%) in the EVT group; the corresponding ABI-based LBP rates were 71.5% (95% CI 61.8% to 81.2%) and 44.0% (95% CI 37.3% to 50.7%).

CONCLUSION

LBP is an important concept in the new global vascular guidelines for assessing the anatomic and hemodynamic status of CLTI patients. The present study found that LBP was significantly lower in the EVT group vs the bypass surgery group.

Chemical-induced craniofacial anomalies caused by disruption of neural crest cell development in a zebrafish model

Background

Craniofacial anomalies are among the most frequent birth defects worldwide, and are thought to be caused by gene‐environment interactions. Genetically manipulated zebrafish simulate human diseases and provide great advantages for investigating the etiology and pathology of craniofacial anomalies. Although substantial advances have been made in understanding genetic factors causing craniofacial disorders, limited information about the etiology by which environmental factors, such as teratogens, induce craniofacial anomalies is available in zebrafish.

Results

Zebrafish embryos displayed craniofacial malformations after teratogen treatments. Further observations revealed characteristic disruption of chondrocyte number, shape and stacking. These findings suggested aberrant development of cranial neural crest (CNC) cells, which was confirmed by gene expression analysis of the CNC. Notably, these observations suggested conserved etiological pathways between zebrafish and mammals including human. Furthermore, several of these chemicals caused malformations of the eyes, otic vesicle, and/or heart, representing a phenocopy of neurocristopathy, and these chemicals altered the expression levels of the responsible genes.

Conclusions

Our results demonstrate that chemical‐induced craniofacial malformation is caused by aberrant development of neural crest. This study indicates that zebrafish provide a platform for investigating contributions of environmental factors as causative agents of craniofacial anomalies and neurocristopathy.

Pancreatic pseudocyst-portal vein fistula: a case treated with EUS-guided cyst-drainage and a review of the literature

Pancreatic pseudocyst and portal vein thrombosis are common conditions resulting from acute and chronic pancreatitis. However, pancreatic pseudocyst-portal vein fistula (PPVF) is a rare and life-threatening complication. In PPVF patients, drainage or operative therapy is necessary under certain conditions, including communication between the pseudocyst and pancreatic duct, pancreatic duct stricture, pancreatic duct stone, and infection that is difficult to control with antibiotics. We describe the case of a 78-year-old woman who presented with an infected pancreatic pseudocyst invading the portal venous system with obstruction due to thromboembolization. Conservative therapy with antibiotics was insufficient. We, therefore, performed endoscopic ultrasound-guided cyst-drainage (EUS-CD). During EUS-CD, PPVF and pseudocyst-pancreatic duct fistula were confirmed by contrast medium injection. Despite the presence of the pseudocyst-pancreatic duct fistula, the pancreatic duct was not visualized in the pancreatic head, suggesting stricture in the main pancreatic duct. We, therefore, performed endoscopic retrograde pancreatography, which revealed pancreatic stone in the main pancreatic duct. Then, we added a 7-Fr pancreatic stent. She was discharged after 89 days of hospitalization. We reviewed the literature on the management of PPVF formation, and EUS-CD is considered to be a good treatment option for PPVF patients without portal vein patency.

Ischemic pancreatitis with infected walled-off necrosis with a colonic fistula after cardiopulmonary bypass successfully treated by endoscopic ultrasound-guided drainage

A 72-year-old man who had been on continuous ambulatory peritoneal dialysis treatment for 10 years underwent cardiopulmonary bypass for aortic valve replacement due to aortic valve stenosis. After surgery, he experienced pancreatitis, and rupture of a splenic artery aneurysm. He went into cardiopulmonary arrest but was successfully treated by transcatheter arterial embolization (TAE) with cardiopulmonary resuscitation. At three weeks after TAE, CT showed heterogeneous enhancement and the accumulation of pancreatic fluid in the pancreatic tail. At 4 months after TAE, he had sepsis and CT showed greater fluid collection with emphysema in comparison to 3 months previously. We diagnosed infected walled-off necrosis (WON). Conservative therapy with antibiotics was not sufficiently effective; thus, we performed endoscopic ultrasound-guided drainage (EUS-D). Contrast imaging revealed WON with colonic fistula. The WON remarkably decreased in size on CT after EUS-D. We experienced a rare case of ischemic acute pancreatitis (AP) caused by cardiopulmonary bypass complicated with infected WON with a colonic fistula. Ischemic AP more frequently shows a severe course with a fatal outcome in comparison to AP of other causes. However, in our case, ischemic AP with infected WON was successfully treated by EUS-D despite the presence of a WON with a colonic fistula.

Genetic dissection of the planarian reproductive system through characterization of Schmidtea mediterranea CPEB homologs

Cytoplasmic polyadenylation is a mechanism of mRNA regulation prevalent in metazoan germ cells; it is largely dependent on Cytoplasmic Polyadenylation Element Binding proteins (CPEBs). Two CPEB homologs were identified in the planarian Schmidtea mediterranea. Smed-CPEB1 is expressed in ovaries and yolk glands of sexually mature planarians, and required for oocyte and yolk gland development. In contrast, Smed-CPEB2 is expressed in the testes and the central nervous system; its function is required for spermatogenesis as well as non-autonomously for development of ovaries and accessory reproductive organs. Transcriptome analysis of CPEB knockdown animals uncovered a comprehensive collection of molecular markers for reproductive structures in S. mediterranea, including ovaries, testes, yolk glands, and the copulatory apparatus. Analysis by RNA interference revealed contributions for a dozen of these genes during oogenesis, spermatogenesis, or capsule formation. We also present evidence suggesting that Smed-CPEB2 promotes translation of Neuropeptide Y-8, a prohormone required for planarian sexual maturation. These findings provide mechanistic insight into potentially conserved processes of germ cell development, as well as events involved in capsule deposition by flatworms.

Cellular and molecular hypoxic response in common carp (Cyprinus carpio) exposed to linear alkylbenzene sulfonate at sublethal concentrations

Linear alkylbenzene sulfonate (LAS) is an anionic surfactant commonly used in cleaning agents such as laundry detergents. Trace amounts of LAS are released into environmental waters after processing in wastewater treatment plants after the use of this chemical. Acute toxicity of LAS has been well-studied using various organisms, and its effects are particularly well known in fish. LAS damages fish gill morphology and induces mucous excretion from these organs. LAS also causes hematological changes. These observations suggest that LAS might induce hypoxic conditions in fish. However, the connections between hypoxia and hematological changes at the cellular and molecular levels remain unknown. Common carp were exposed to LAS at concentrations of 625, 1250, and 2500 μg/L for 96 h. A total of 9-10 fish were sampled at the end of the exposure period for each concentration. For hematological analysis, carp blood was sampled from the caudal vein. Gill tissue was used for real-time PCR analysis to evaluate transcriptional changes of hypoxia-induced genes. The number of normal red blood cells and the number of immature red blood cells were significantly decreased and increased, respectively, in fish exposed to 2500 µg/L LAS. The hypoxic marker genes hypoxia inducible factor 1α, myoglobin 1, and erythropoietin 2 were upregulated in these fish. Our results suggest that LAS decreases erythrocyte numbers and induces hypoxic conditions. In addition, LAS-exposed fish increase production of immature erythrocytes and upregulate myoglobin expression in gills to improve oxygen transport and absorption. © 2015 Wiley Periodicals, Inc. Environ Toxicol 32: 122-130, 2017.

Analysis of Stem Cell Motility In Vivo Based on Immunodetection of Planarian Neoblasts and Tracing of BrdU-Labeled Cells After Partial Irradiation

Planarian flatworms have become an important system for the study of stem cell behavior and regulation in vivo. These organisms are able to regenerate any part of their body upon damage or amputation. A crucial cellular event in the process of planarian regeneration is the migration of pluripotent stem cells (known as neoblasts) to the site of injury. Here we describe two approaches for analyzing migration of planarian stem cells to an area where these have been ablated by localized X-ray irradiation. The first approach involves immunolabeling of mitotic neoblasts, while the second is based on tracing stem cells and their progeny after BrdU incorporation. The use of planarians in studies of cell motility is suitable for the identification of factors that influence stem cell migration in vivo and is amenable to RNA interference or pharmacological screening.

ERK signaling controls blastema cell differentiation during planarian regeneration

The robust regenerative ability of planarians depends on a population of somatic stem cells called neoblasts, which are the only mitotic cells in adults and are responsible for blastema formation after amputation. The molecular mechanism underlying neoblast differentiation associated with blastema formation remains unknown. Here, using the planarian Dugesia japonica we found that DjmkpA, a planarian mitogen-activated protein kinase (MAPK) phosphatase-related gene, was specifically expressed in blastema cells in response to increased extracellular signal-related kinase (ERK) activity. Pharmacological and genetic [RNA interference (RNAi)] approaches provided evidence that ERK activity was required for blastema cells to exit the proliferative state and undergo differentiation. By contrast, DjmkpA RNAi induced an increased level of ERK activity and rescued the differentiation defect of blastema cells caused by pharmacological reduction of ERK activity. These observations suggest that ERK signaling plays an instructive role in the cell fate decisions of blastema cells regarding whether to differentiate or not, by inducing DjmkpA as a negative regulator of ERK signaling during planarian regeneration.

Role of c-Jun N-terminal kinase activation in blastema formation during planarian regeneration

The robust regenerative abilities of planarians absolutely depend on a unique population of pluripotent stem cells called neoblasts, which are the only mitotic somatic cells in adult planarians and are responsible for blastema formation after amputation. Little is known about the molecular mechanisms that drive blastema formation during planarian regeneration. Here we found that treatment with the c-Jun N-terminal kinase (JNK) inhibitor SP600125 blocked the entry of neoblasts into the M-phase of the cell cycle, while allowing neoblasts to successfully enter S-phase in the planarian Dugesia japonica. The rapid and efficient blockage of neoblast mitosis by treatment with the JNK inhibitor provided a method to assess whether temporally regulated cell cycle activation drives blastema formation during planarian regeneration. In the early phase of blastema formation, activated JNK was detected prominently in a mitotic region (the "postblastema") proximal to the blastema region. Furthermore, we demonstrated that undifferentiated mitotic neoblasts in the postblastema showed highly activated JNK at the single cell level. JNK inhibition by treatment with SP600125 during this period caused a severe defect of blastema formation, which accorded with a drastic decrease of mitotic neoblasts in regenerating animals. By contrast, these animals still retained many undifferentiated neoblasts near the amputation stump. These findings suggest that JNK signaling plays a crucial role in feeding into the blastema neoblasts for differentiation by regulating the G2/M transition in the cell cycle during planarian regeneration.

A role of D domain-related proteins in differentiation and migration of embryonic cells in Xenopus laevis

We have characterized a cDNA clone, rdd (repeated D domain-like), that encodes for a secretory protein consisting of repeated domains of cysteine-rich sequence. Whole-mount in situ hybridization analysis revealed that rdd2, rdd3 and rdd4 are transiently expressed in the ventral and lateral mesoderm and the overlying ectoderm at the late gastrula and tailbud stages. Morpholino oligonucleotide (MO) was used to inhibit the translation of endogenous rdd3 and rdd4, and we found that the circulation of red blood cells completely disappears in the MO-injected tadpoles. Histological analysis showed that formation of the ventral aorta, dorsal aorta and posterior cardinal vein in the trunk region was severely disorganized in these animals. Injection of MO affected the expression of alpha-globin, a terminal differentiation marker of red blood cells, but did not affect the expression of scl, flk-1 or tie-2, suggesting that angiopoietic and hematopoietic precursor cells differentiate normally in the rdd-depleted embryo. The transplantation of labeled tissues followed by tracing of the donor cells revealed a role of rdds in migration of the embryonic angioblasts and myeloid cells. These observations first demonstrate the role of the novel cysteine-rich proteins in migration of the embryonic cells.