The Long-Term Natural History of Fibrous Dysplasia.

Fibrous dysplasia (FD), a developmental, nonfamilial, benign anomaly of bone development, is characterized by the replacement of normal bone by proliferating fibro-osseous tissue. Marked craniofacial deformities, functional disturbances, and emotional stress are major indications for treatment, and various surgical procedures have been performed; however, excision and regrowth issues have also been reported. While several treatment options are available, no studies have reported the natural history of untreated FD. Here, we report 2 patients, aged 73 and 50 years, respectively, who had not received treatment. Both patients presented to the hospital complaining of noise when moving their heads. Computed tomography scans showed niveau with honeycomb cavities in both patients, indicating abscess formation, and resection was performed. Relatively large cranial FD leads to the development of central necrosis over time. In such cases, surgical intervention should be performed at an early disease stage.

Alveolar adenoma with a single cyst: A case report.

Alveolar adenoma is a rare and benign pulmonary tumor, which originates from type II pneumocytes and is often incidentally identified on radiographic images. Alveolar adenoma presents as a peripleural, solitary and cystic nodule in the lung and may mimic other types of lung tumors, thus rendering its differential diagnosis difficult. Alveolar adenoma is diagnosed based on histopathological and immunohistochemical analyses. The present study describes the case of a 50-year-old male patient with alveolar adenoma. He visited a local doctor ~3 years prior due to left chest pain. A chest computed tomography scan revealed a cystic lesion in segment 8 of the left lung. A nodular shadow appeared in the cyst and gradually increased in size; the patient was thus referred to the authors' hospital. The nodule was well-defined, solitary and solid; thus, lung cancer or aspergilloma were suspected. Thoracoscopic wedge resection was performed as diagnostic therapy. The frozen sections were non-diagnostic, and a pathological examination revealed an alveolar adenoma with no evidence of malignancy and a negative culture. The patient had a good post-operative course, with no sign of recurrence at the follow-up evaluation 46 months later. On the whole, alveolar adenoma is a rare, benign pulmonary tumor that is difficult to diagnose pre-operatively.

Standardized Classification of Lung Adenocarcinoma Subtypes and Improvement of Grading Assessment Through Deep Learning.

The histopathologic distinction of lung adenocarcinoma (LADC) subtypes is subject to high interobserver variability, which can compromise the optimal assessment of patient prognosis. Therefore, this study developed convolutional neural networks capable of distinguishing LADC subtypes and predicting disease-specific survival, according to the recently established LADC tumor grades. Consensus LADC histopathologic images were obtained from 17 expert pulmonary pathologists and one pathologist in training. Two deep learning models (AI-1 and AI-2) were trained to predict eight different LADC classes. Furthermore, the trained models were tested on an independent cohort of 133 patients. The models achieved high precision, recall, and F1 scores exceeding 0.90 for most of the LADC classes. Clear stratification of the three LADC grades was reached in predicting the disease-specific survival by the two models, with both Kaplan-Meier curves showing significance (P = 0.0017 and 0.0003). Moreover, both trained models showed high stability in the segmentation of each pair of predicted grades with low variation in the hazard ratio across 200 bootstrapped samples. These findings indicate that the trained convolutional neural networks improve the diagnostic accuracy of the pathologist and refine LADC grade assessment. Thus, the trained models are promising tools that may assist in the routine evaluation of LADC subtypes and grades in clinical practice.

Overcoming the Interobserver Variability in Lung Adenocarcinoma Subtyping: A Clustering Approach to Establish a Ground Truth for Downstream Applications.

CONTEXT.­: The accurate identification of different lung adenocarcinoma histologic subtypes is important for determining prognosis but can be challenging because of overlaps in the diagnostic features, leading to considerable interobserver variability. OBJECTIVE.­: To provide an overview of the diagnostic agreement for lung adenocarcinoma subtypes among pathologists and to create a ground truth using the clustering approach for downstream computational applications. DESIGN.­: Three sets of lung adenocarcinoma histologic images with different evaluation levels (small patches, areas with relatively uniform histology, and whole slide images) were reviewed by 17 international expert lung pathologists and 1 pathologist in training. Each image was classified into one or several lung adenocarcinoma subtypes. RESULTS.­: Among the 4702 patches of the first set, 1742 (37%) had an overall consensus among all pathologists. The overall Fleiss κ score for the agreement of all subtypes was 0.58. Using cluster analysis, pathologists were hierarchically grouped into 2 clusters, with κ scores of 0.588 and 0.563 in clusters 1 and 2, respectively. Similar results were obtained for the second and third sets, with fair-to-moderate agreements. Patches from the first 2 sets that obtained the consensus of the 18 pathologists were retrieved to form consensus patches and were regarded as the ground truth of lung adenocarcinoma subtypes. CONCLUSIONS.­: Our observations highlight discrepancies among experts when assessing lung adenocarcinoma subtypes. However, a subsequent number of consensus patches could be retrieved from each cluster, which can be used as ground truth for the downstream computational pathology applications, with minimal influence from interobserver variability.

Primary Pancreatic Mantle Cell Lymphoma Diagnosed via Endoscopic Ultrasound-Guided Fine-Needle Aspiration.

Primary pancreatic lymphomas (PPLs) are rare, and the histological classification of these tumors is difficult. To accurately diagnose and determine the appropriate treatment for PPLs, sufficient sample amounts are necessary. Here, we report a 73-year-old man with a primary pancreatic mantle cell lymphoma. Histological samples were obtained via endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). The tumor cells predominantly composed of atypical small to medium round cells, with diffuse immunoreactivity of CD20 and cyclin D1. In addition, immunoglobulin gene H chain rearrangement was detected. The patient underwent chemotherapy, resulting in complete remission. Eight years after the initiation of chemotherapy, the patient was still alive. EUS-FNA could be a useful and safe diagnostic modality for PPLs by providing enough samples for testing.

Presence of heat shock protein 47-positive fibroblasts in cancer stroma is associated with increased risk of postoperative recurrence in patients with lung cancer.

BACKGROUND: Heat shock protein 47 (HSP47), a collagen-binding protein, has a specific role in the intracellular processing of procollagen production. HSP47 expression is associated with cancer growth and metastasis in several types of cancers. However, none of the studies have assessed whether HSP47 expression is associated with the risk of postoperative recurrence of lung cancer until now. Therefore, we aimed to assess this association. METHODS: The study population consisted of a cohort of consecutive patients who underwent surgery for lung cancer at Nagasaki University Hospital, Nagasaki, Japan, from January 2009 to December 2010. Patient characteristics, survival and disease-free survival (DFS), and laboratory findings were compared between patients who tested positive and negative for HSP47 expression in lung cancer cells and between those who showed high and low numbers of HSP47-positive fibroblasts in cancer stroma. RESULTS: A total of 133 patients underwent surgery for lung cancer. Sixty-seven patients (50.4%) had HSP47-positive cancer cells, and 91 patients (68.4%) had a higher number of HSP47-positive fibroblasts. The patients with a high number of HSP47-positive fibroblasts had a shorter DFS than those with a low number of HSP47-positive fibroblasts. Multivariate analysis identified only the presence of a high number of HSP47-positive fibroblasts as an independent risk factor for recurrence of lung cancer after surgery (odds ratio, 4.371; 95% confidence interval, 1.054-29.83; P = 0.042). CONCLUSION: The present study demonstrated that the presence of a high number of HSP47-positive fibroblasts in the cancer stroma was a risk factor for recurrence of lung cancer after surgery.

Prognostic impact of mucin spread, tumor cell spread, and invasive size in invasive mucinous adenocarcinoma of the lung.

OBJECTIVES: The pathological T descriptor of lung invasive mucinous adenocarcinoma (IMA) is currently defined according to mucin spread, whereas that of lung non-mucinous adenocarcinoma is defined according to invasive lesion. This study aimed to evaluate and compare the prognostic impact of mucin spread, tumor cell spread, and invasive lesion in patients with lung IMA. MATERIALS AND METHODS: Twenty-seven patients with completely resected pT1-4N0M0 IMA were evaluated. The radiological size (RS), mucin spread size (MS), tumor cell spread size (TS), and invasive size (IS) of the primary tumors were determined. Cox proportional hazards models were used to estimate recurrence-free survival (RFS). Because the MS, TS, and IS may be mutually confounding factors, they were evaluated using separate multivariate models including potential prognostic factors identified as significant on univariate analyses. RESULTS: The median postoperative follow-up time was 4.9 years. TS and IS were significantly smaller than RS by a median of 0.3 cm (p = 0.027) and 1.4 cm (p < 0.0001), whereas MS and RS were not significantly different (p > 0.999). Univariate analyses identified T descriptors defined by MS, TS, and IS as potentially negative prognostic factors, in addition to age >75 years and carcinoembryonic antigen >5 ng/mL. Multivariate analyses revealed that T factors defined by MS, TS, and IS were significant predictors of RFS (p < 0.0001, p = 0.0002, and p = 0.0067, respectively). CONCLUSION: MS is a reasonable determinant of the pathological T descriptor of lung IMA. TS and IS are potential candidates, although they remain discordant with RS. If the TS or IS is to be considered a candidate for the pathological T descriptor of lung IMA, the discordance with RS should first be resolved. If IS is used to define pathological T factor, clear criteria for mucinous AIS/MIA with IMA features should be developed.

Simple, Frequent Indicator for Personal Identification-Postmortem and Antemortem Abdominal Computed Tomography Findings of a Charred Body.

Postmortem personal identification in forensic science is performed using various methods. However, severely burnt bodies are hard to identify using odontological or skeletal features because of carbonization, and sometimes DNA profiling is impracticable because of the unavailability of the relatives. We present a case of a burn victim found after a house fire. Personal identification was attempted, but the body was heavily charred to the bones and the use of physical appearance was impracticable. There were no known relatives or personal belongings of the deceased for comparison of DNA typing. We obtained a series of abdominal computed tomography (CT) scans taken antemortem and found bilateral multiple renal cysts, left renal artery calcification, and a big right inguinal hernia, which matched the deceased's postmortem CT findings and autopsy findings. To date, studies of identification by CT have acted for a rise in precision, but they require complicated calculation or high graphical methods. Calcification of the arteries or renal cysts seen in our case are very common lesions present in many adults with abundant variation; thus, they may be helpful as simple indicators for identification.

Autoerotic asphyxia using a plastic bag loosely covering the head over a gas mask.

Autoerotic death is defined as the accidental death of an individual while masturbating, caused by a device or material used to enhance the sexual response. Here we report an autopsy case of autoerotic death and review the literature. A healthy, single, 33-year-old Japanese male was found dead in his room in a prone position. He was wearing a used gas mask and a plastic bag over his head; the opening of that bag was loosely secured around the neck with a belt. He had no underwear beneath his upper and lower work clothes and the zipper of his pants was open. Adult magazines and DVDs featuring male subjects and other adult toys were found in his room. Images of people wearing gas masks and rubber suits, as well as of individuals whose whole bodies were tied with ropes, were discovered on his personal computer. Records of purchasing full-body tights were also found. Lesions and injuries that could have caused his death were not found in the autopsy or in any of the various examinations. The cause of death was determined to be suffocation assumed to be caused by the plastic bag covering the mask's ventilation. Suicide and homicide were ruled out based on the police investigation of the scene of the victim's death and the attendant circumstances and environment. The death was thus determined to be an accident. We see no major differences in the feature of autoerotic death between Japanese cases and those in the Western countries.

Peripheral Ulcerative Keratitis Associated with Granulomatosis with Polyangiitis Emerging Despite Cyclophosphamide, Successfully Treated with Rituximab.

A 67-year-old Japanese man was diagnosed with granulomatosis with polyangiitis based on the presence of right maxillary sinusitis, proteinase 3 antineutrophil cytoplasmic antibody positivity, and right scleritis. A conjunctival biopsy specimen showed neutrophil-predominant infiltration around the vessels without granuloma. Because there was a risk of blindness, pulsed methylprednisolone and intravenous cyclophosphamide pulse therapy (IVCY) were started. However, it was ineffective, and peripheral ulcerative keratitis newly emerged. We promptly switched the treatment from IVCY to rituximab, and ophthalmologists performed amniotic membrane transplantation, which avoided blindness. The close and effective working relationship between physicians and ophthalmologists improved our patient's ocular prognosis.

Predictive Performance of Four Programmed Cell Death Ligand 1 Assay Systems on Nivolumab Response in Previously Treated Patients with Non-Small Cell Lung Cancer.

INTRODUCTION: Nivolumab has demonstrated efficacy against metastatic NSCLC. Four programmed cell death ligand 1 (PD-L1) immunohistochemistry (IHC) assay systems are available for identification of responders among patients with NSCLC, and these assays show some differing characteristics. Accordingly, in this study, we evaluated the ability of these assays to identify responders to nivolumab therapy. METHODS: We retrospectively analyzed patients with previously treated advanced NSCLC, who received nivolumab between January 2016 and September 2016. Specimens were stained using four PD-L1 IHC assays (28-8, 22C3, SP142, and SP263). We classified patients as having test results that were strongly positive (tumor proportion score [TPS] ≥50%), weakly positive (TPS 1%-49%), or negative (TPS <1%). RESULTS: A total of 40 patients with NSCLC and their specimens were analyzed. Analytical comparisons demonstrated good concordance of PD-L1-stained tumor cells among the 28-8, 22C3, and SP263 assays (weighted κ coefficient 0.64-0.71), whereas the SP142 assay showed lower concordance with other assays (weighted κ coefficient 0.39-0.55). Progression-free survival in patients showing strongly positive PD-L1 staining classified by 28-8, 22C3, and SP263 assays was significantly longer than that in patients with a negative result for PD-L1 staining. Predictive performance of response to nivolumab, as assessed by receiver operating characteristic analysis, was also equivalent among the 28-8, 22C3, and SP263 assays (area under the curve 0.75-0.82), whereas the SP142 assay exhibited lower predictive performance (area under the curve 0.68). CONCLUSIONS: The 28-8, 22C3, and SP263 PD-L1 IHC assays showed equivalent predictive performance, whereas the SP142 assay showed lower predictive performance.

Early Immune-Related Adverse Events and Association with Outcome in Advanced Non-Small Cell Lung Cancer Patients Treated with Nivolumab: A Prospective Cohort Study.

INTRODUCTION: Retrospective studies have shown immune-related adverse events (irAEs) to be associated with better prognosis. However, no prospective clinical trials have been conducted, and little is known regarding the association between irAEs and the outcome of patients with NSCLC after treatment with immunotherapy. METHODS: We conducted a prospective cohort study of patients with advanced NSCLC who were treated with nivolumab between January and December 2016. The association between clinical outcome and irAEs 2 to 6 weeks after commencement of nivolumab treatment was investigated. IrAEs were assessed by at least three independent medical professionals. RESULTS: A total of 43 patients were enrolled, including 19 patients with irAEs 2 weeks after commencement of nivolumab treatment. Common irAEs included rash, pyrexia, and diarrhea. Programmed cell death ligand 1-positive tumor cell expression was not significantly different between patients with and without irAEs. The objective response and disease control rates were higher in patients with irAEs than in those without irAEs (37% versus 17% and 74% versus 29% [p = 0.17 and p < 0.01], respectively]). Patients with irAEs were associated with a significantly longer median progression-free survival than those without (6.4 months [95% confidence interval: 2.5-not reached] versus 1.5 months [95% confidence interval: 1.2-2.3] [p = 0.01]). These findings were comparable to those for patients with and without irAEs 6 weeks after commencement of nivolumab treatment. CONCLUSIONS: Early irAEs are associated with a better outcome after treatment with immunotherapy. We predicted responses to nivolumab by using early irAEs. Further research is needed to elucidate the mechanisms of these associations.

Mitochondrial m-calpain opens the mitochondrial permeability transition pore in ischemia-reperfusion.

BACKGROUND/OBJECTIVES: Opening of the mitochondrial permeability transition pore (mPTP) is involved in ischemia-reperfusion injury. Isoforms of Ca(2+)-activated cysteine proteases, calpains, are implicated in the development of myocardial infarction in ischemia-reperfusion. Growing evidence has revealed the presence of calpains in the mitochondria. We aimed to characterize mitochondrial calpains in the rat heart and to investigate the roles of calpains in mPTP opening after ischemia-reperfusion. METHODS AND RESULTS: Western blotting analysis showed the expression of µ-calpain, m-calpain and calpain 10 in mitochondria isolated from male Sprague-Dawley rats, but casein zymography detected only m-calpain activity. Subcellular fractionation of mitochondria demonstrated the distribution of m-calpain to the matrix fraction. Addition of >500µM of Ca(2+) to isolated mitochondria induced mitochondrial swelling, reflecting mPTP opening, and calpain activation. Ca(2+)-induced mitochondrial swelling was inhibited partially by the calpain inhibitor calpeptin. These results support a partial contribution of calpain in the opening of the mPTP. The addition of Ca(2+) to the mitochondria induced inactivation of complex I of the electron transport chain, and cleavage of the ND6 complex I subunit, which were inhibited by calpeptin. Mitochondria isolated from rat hearts that underwent 30min of coronary occlusion followed by 30min of reperfusion showed activation of mitochondrial calpains, ND6 cleavage, complex I inactivation, and mPTP opening, which were inhibited by pretreatment with calpain inhibitor 1. CONCLUSIONS: We demonstrated for the first time the presence of mitochondrial matrix m-calpain, and its contribution to complex I inactivation and mPTP opening after postischemic reperfusion in the rat heart.

MDMA induces cardiac contractile dysfunction through autophagy upregulation and lysosome destabilization in rats.

The underlying mechanisms of cardiotoxicity of 3,4-methylenedioxymethylamphetamine (MDMA, "ecstasy") abuse are unclear. Autophagy exerts either adaptive or maladaptive effects on cardiac function in various pathological settings, but nothing is known on the role of autophagy in the MDMA cardiotoxicity. Here, we investigated the mechanism through which autophagy may be involved in MDMA-induced cardiac contractile dysfunction. Rats were injected intraperitoneally with MDMA (20mg/kg) or saline. Left ventricular (LV) echocardiography and LV pressure measurement demonstrated reduction of LV systolic contractility 24h after MDMA administration. Western blot analysis showed a time-dependent increase in the levels of microtubule-associated protein light chain 3-II (LC3-II) and cathepsin-D after MDMA administration. Electron microscopy showed the presence of autophagic vacuoles in cardiomyocytes. MDMA upregulated phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) at Thr172, mammalian target of rapamycin (mTOR) at Thr2446, Raptor at Ser792, and Unc51-like kinase (ULK1) at Ser555, suggesting activation of autophagy through the AMPK-mTOR pathway. The effects of autophagic inhibitors 3-methyladenine (3-MA) and chloroquine (CQ) on LC3-II levels indicated that MDMA enhanced autophagosome formation, but attenuated autophagosome clearance. MDMA also induced release of cathepsins into cytosol, and western blotting and electron microscopy showed cardiac troponin I (cTnI) degradation and myofibril damage, respectively. 3-MA, CQ, and a lysosomal inhibitor, E64c, inhibited cTnI proteolysis and improved contractile dysfunction after MDMA administration. In conclusion, MDMA causes lysosome destabilization following activation of the autophagy-lysosomal pathway, through which released lysosomal proteases damage myofibrils and induce LV systolic dysfunction in rat heart.

Intermittent-hypoxia induced autophagy attenuates contractile dysfunction and myocardial injury in rat heart.

Sleep apnea syndrome (SAS) is considered to be associated with heart failure (HF). It is known that autophagy is induced in various heart diseases thereby promotes survival, but its excess may be maladaptive. Intermittent hypoxia (IH) plays pivotal role in the pathogenesis of SAS. We aimed to clarify the relationships among IH, autophagy, and HF. Rats underwent IH at a rate of 20cycles/h (nadir of 4% O2 to peak of 21% O2 with 0% CO2) or normal air breathing (control) for 8h/d for 3weeks. IH increased the cardiac LC3II/LC3I ratio. The IH induced upregulation of LC3II was attenuated by the administration of an inhibitor of autophagosome formation 3-methyladenine (3-MA), but enhanced by an inhibitor of autophagosome-lysosome fusion chloroquine (CQ), showing enhanced autophagic flux in IH hearts. Electron microscopy confirmed an increase in autophagosomes and lysosomes in IH. With 3-MA or CQ, IH induced progressive deterioration of fractional shortening (FS) on echocardiography over 3weeks, although IH, 3-MA, or CQ alone had no effects. With CQ, IH for 4weeks increased serum troponin T levels, reflecting necrosis. Western blotting analyses showed dephosphorylation of Akt and mammalian target of rapamycin (mTOR) at Akt (Ser2448, 2481) sites, suggesting the activation of autophagy via Akt inactivation. Conclusions. IH-mediated autophagy maintains contractile function, whereas when autophagy is inhibited, IH induces systolic dysfunction due to myocyte necrosis. General significance. This study highlighted the potential implications of autophagy in cardio-protection in early SAS patients without comorbidity, reproduced in normal rats by 3~4weeks of IH.

Connexin-43 hemichannels contribute to the propagation of µ-calpain-mediated neuronal death in a cortical ablation injury model.

We investigated the role of the astrocytic and neuronal hemichannels (HCs) in the spread of cortical neuronal death in a rat cortical injury model. Over time (by 6 h), propidium iodide (PI)-positive cells with labeling either with anti-neuron specific enolase or anti-parvalbumin (indicating GABAnergic interneurons) antibody spread in the deep cortical layers adjacent to the injury and co-localized with activated µ-calpain. Connexin (Cx)-43, glial fibrillary acidic protein (GFAP), activated µ-calpain and α-fodrin breakdown product (FBP) increased post-injury, peaking at 1 h, in the injury and adjacent areas. GFAP-Cx43-positive reactivated astrocytes exhibited similar distribution to the dead neurons. Cx43 and Cx36 primarily comprise HCs in the astrocyte and neuron, respectively. Ethidium bromide (EtBr) uptake was enhanced post-injury, and confirmed in the Cx43- and Cx36-positive cells. A Cx43-HC inhibitor Gap26 prevented the opening of the Cx43-HC and Cx36-HC, µ-calpain activation, α-fodrin proteolysis and death in the deep cortical neurons. Collectively, opening of the astrocytic Cx43-HC and neuronal Cx36-HC would induce the regional spread of cortical neuronal death through µ-calpain activation in the rat brain injury model.

Brief exposure to carbon monoxide preconditions cardiomyogenic cells against apoptosis in ischemia-reperfusion.

We examined whether and how pretreatment with carbon monoxide (CO) prevents apoptosis of cardioblastic H9c2 cells in ischemia-reperfusion. Reperfusion (6 h) following brief ischemia (10 min) induced cytochrome c release, activation of caspase-9 and caspase-3, and apoptotic nuclear condensation. Brief CO pretreatment (10 min) or a caspase-9 inhibitor (Z-LEHD-FMK) attenuated these apoptotic changes. Ischemia-reperfusion increased phosphorylation of Akt at Ser472/473/474, and this was enhanced by CO pretreatment. A specific Akt inhibitor (API-2) blunted the anti-apoptotic effects of CO in reperfusion. In normoxic cells, CO enhanced O2(-) generation, which was inhibited by a mitochondrial complex III inhibitor (antimycin A) but not by a NADH oxidase inhibitor (apocynin). The CO-enhanced Akt phosphorylation was suppressed by an O2(-) scavenger (Tiron), catalase or a superoxide dismutase (SOD) inhibitor (DETC). These results suggest that CO pretreatment induces mitochondrial generation of O2(-), which is then converted by SOD to H2O2, and subsequent Akt activation by H2O2 attenuates apoptosis in ischemia-reperfusion.

Autopsy report on central pontine myelinolysis triggered by vomiting associated with digoxin intoxication.

An 87-year-old male, prescribed digoxin and furosemide for congestive heart failure and Alzheimer disease, had dehydration and anemia due to poor food intake and hemorrhagic cystitis. Repeated vomiting due to an upper respiratory infection caused disturbance of consciousness and hypotension. The patient was admitted to hospital and diagnosed with digoxin intoxication and hypernatremia. The serum sodium (Na(+)) level was corrected, but the patient died 4 days after admission following uncontrollable seizure. A histologic examination after an autopsy revealed characteristic findings of central pontine myelinolysis (CPM). This is the first autopsy report on CPM triggered by vomiting in association with digoxin administration.

Determination of amobarbital and phenobarbital in serum by gas chromatography-mass spectrometry with addition of formic acid to the solvent.

A rapid and accurate method for quantification of amobarbital and phenobarbital was developed using gas chromatography-mass spectrometry (GC-MS) without derivatization. Though the compounds measured without derivatization showed low sensitivity because of adsorption, addition of 3% formic acid to the solvent improved the sensitivity for the analytes. Taking account of matrix effect, solid-phase and liquid-liquid extraction from serum were examined. The correlation coefficients of the calibration curves were 0.9995 or better, and the accuracy and precision of intraday and interday assays were in line with Food and Drug Administration (FDA) criteria.

Hemichannels in cardiomyocytes open transiently during ischemia and contribute to reperfusion injury following brief ischemia.

The aim of this study was to investigate changes in hemichannel activity during in vitro simulated ischemia [oxygen-glucose deprivation (OGD)] and the contribution of hemichannels to ischemia-reperfusion injury in rat neonatal cardiomyocytes. Dye uptake assays showed that hemichannels opened as OGD progressed, peaking after 1 h, and then closed, returning to the pre-OGD state after 2 h of OGD. The increase in dye uptake after 1 h of OGD was inhibited by hemichannel blockers (lanthanum chloride and a connexin 43 mimetic peptide, Gap26). During OGD, intracellular Ca(2+) concentration ([Ca(2+)](i)) began to increase after 1 h and reached several micromolar after 2 h. After 1 h of OGD, Gap26 inhibited the increases in hemichannel activity and [Ca(2+)](i). In contrast, dantrolene [an endo(sarco)plasmic reticulum Ca(2+) release inhibitor] suppressed the increase in [Ca(2+)](i), but not in hemichannel activity. After 2 h of OGD, the combined administration of 2',4'-dichlorobenzamil and dantrolene reduced [Ca(2+)](i) to <1 microM and increased hemichannel activity to the level attained after 1 h of OGD. Simulated ischemia-reperfusion, induced by 1 h of OGD followed by 2 h of recovery, reduced cell viability to 54% of the control level. The addition of Gap26 to OGD medium improved viability to 80% of the control level. In conclusion, this study demonstrated that 1) hemichannels open transiently during OGD, 2) closure of hemichannels, but not their opening, is regulated by an increase in [Ca(2+)](i) during OGD, and 3) open hemichannels contribute to cell injury during recovery from OGD.