Dynamics of Laterality in the Cuttlefish Sepia recurvirostra through Interactions with Prey Prawns.

Predator-prey interactions based on laterality have recently been observed between fishes and their prey populations. Maintenance of antisymmetric dimorphism by frequency-dependent selection has been reported in fish, but has not been observed in invertebrates. Over 10 years, we investigated long-term changes in the "ratio of laterality" (frequency of righty morphs in a population) in the cuttlefish Sepia recurvirostra and its potential prey prawns Penaeus semisulcatus and Metapenaeus endeavouri in the Visayan Sea, the Philippines. The morphological laterality of cuttlefish and prey prawns was defined by measuring the asymmetry of the cuttlebone and carapace, respectively. Cuttlefish and prey prawns showed morphological antisymmetry, being composed with righty morphs and lefty morphs. The ratio of laterality of cuttlefish and one prey prawn oscillated significantly, but the oscillation was not strongly synchronized. The ratio of laterality of cuttlefish followed that of the prey prawn, indicating that predation biased to each laterality occurred in relation to their laterality. These results suggest that the lateral dimorphism of cuttlefish is maintained through frequency-dependent selection on lateral morphs of the predator cuttlefish and prey prawns. Our findings provide new insight into the ecological significance and antisymmetry maintenance mechanism in relation to interspecific interactions in marine invertebrates.

Flumioxazin, a PPO inhibitor: A weight-of-evidence consideration of its mode of action as a developmental toxicant in the rat and its relevance to humans.

Flumioxazin, is a herbicide that has inhibitory activity on protoporphyrinogen oxidase (PPO), a key enzyme in the biosynthetic pathway for heme. Flumioxazin induces anemia and developmental toxicity in rats, including ventricular septal defect and embryofetal death. Studies to elucidate the mode of action (MOA) of flumioxazin as a developmental toxicant and to evaluate its relevance to humans have been undertaken. The MOA in the rat has now been elucidated. The first key event is PPO inhibition, which results in reduced heme synthesis in embryonic erythroblasts. The critical window for this effect is gestational day 12 when almost all erythroblasts are at the polychromatophilic stage, synthesizing heme very actively. Embryonic anemia/hypoxemia is induced and the heart pumps more strongly as a compensatory action during organogenesis, leading to thinning of the ventricular walls and failure of the interventricular septum to build completely and close. Investigations showed that this MOA is specific to rats and has no relevancy to humans. Flumioxazin inhibited PPO in rat hepatocyte mitochondria more strongly than in human. A 3-dimensional molecular simulation revealed that species differences in binding affinity of flumioxazin to PPO, observed previously in vitro, were due to differences in binding free energy. In vitro studies using several types of rat and human cells (erythroblasts derived from erythroleukemia cell lines, cord blood, or pluripotent stem cells), showed that flumioxazin decreased heme synthesis in rat cells but not in human cells, demonstrating a clear, qualitative species difference. Considering all available information, including data from PBPK modelling in rat and human, as well as the fact that anemia is not a symptom in patients with variegate porphyria, a congenital hereditary PPO defect, shows that the sequence of events leading to adverse effects in the rat embryo and fetus are very unlikely to occur in humans.

Successful outcome of retrograde pancreatojejunostomy for chronic pancreatitis and infected pancreatic cysts: A case report.

BACKGROUND: Chronic pancreatitis occasionally requires surgical treatment that can be performed with various techniques. Often, this type of surgery presents with postoperative complications. We report a case of a successful retrograde pancreatojejunostomy for chronic pancreatitis and infected pancreatic cysts. CASE SUMMARY: A 62-year-old male with a 10-year history of chronic pancreatitis presented with epigastric pain for one week and a 20 kg weight loss over one year. Computed tomography showed stones in the pancreas (mainly the head), expansion of the main pancreatic duct, and thinning of the pancreatic parenchyma. Magnetic resonance imaging showed infected pancreatic cysts connected to the stomach with a fistula from the splenic hilum to the caudal portion of the liver's lateral segment. An endoscopic retrograde pancreatography was performed; the guide wires could not pass through the stones in the pancreas and therefore, drainage of the main pancreatic duct was not achieved. Next, a distal pancreatomy and splenectomy were performed; however, the pancreatic juice in the remaining parenchyma was blocked by the stones. Hence, we performed a retrograde pancreatojejunostomy and Roux-en-Y anastomosis. The patient had no postoperative complications and was discharged from the hospital on postoperative day 14. CONCLUSION: A distal pancreatomy, retrograde pancreatojejunostomy, and Roux-en-Y anastomosis could be an effective surgical procedure for intractable chronic pancreatitis.

Schwannoma mimicking pancreatic carcinoma: A case report.

BACKGROUND: Schwannoma of the pancreas is extremely rare. We report a case of pancreatic schwannoma that was difficult to distinguish from pancreatic carcinoma before surgery. CASE SUMMARY: A 66-year-old male underwent a right-lobe hepatectomy for hepatocellular carcinoma. Post-surgical computed tomography showed a 10 mm long solid mass with ischemia, with no expansion into the main pancreatic duct. Upon magnetic resonance cholangiopancreatography, the tumor had high signal intensity in diffusion weighted images, consistent with pancreatic carcinoma. Endoscopic ultrasound (EUS) was performed to obtain more information about the tumor, and showed a 14 mm solid and hypoechoic mass in the pancreatic body. Contrast enhanced EUS revealed that the tumor showed a hyperechoic mass in the early phase, and the contrasting effect continuation was very short; findings also consistent with pancreatic carcinoma. Thus, we preoperatively diagnosed his condition as a pancreatic carcinoma and performed distal pancreatectomy with splenectomy. Microscopic examination showed that the tumor was in fact a benign schwannoma. Histology showed a proliferation of spindle-shaped cell in a vague fascicular and haphazard pattern, with palisading arrangement. CONCLUSION: Schwannoma of the pancreas is very rare, however, clinicians should consider schwannoma as the differential diagnosis for pancreatic tumors.

Different effects of an N-phenylimide herbicide on heme biosynthesis between human and rat erythroid cells.

Rat developmental toxicity including embryolethality and teratogenicity (mainly ventricular septal defects and wavy ribs) were produced by S-53482, an N-phenylimide herbicide that inhibits protoporphyrinogen oxidase (PPO) common to chlorophyll and heme biosynthesis. The sequence of key biological events in the mode of action has been elucidated as follows: inhibition of PPO interferes with normal heme synthesis, which causes loss of blood cells leading to fetal anemia, embryolethality and the development of malformations. In this study we investigated whether the rat is a relevant model for the assessment of the human hazard of the herbicide. To study effects on heme biosynthesis, human erythroleukemia, human cord blood, and rat erythroleukemia cells were treated with the herbicide during red cell differentiation. Protoporphyrin IX, a marker of PPO inhibition, and heme were determined. We investigated whether synchronous maturation of primitive erythropoiesis, which can contribute to massive losses of embryonic blood, occurs in rats. The population of primitive erythroblasts was observed on gestational days 11 through 14. Heme production was suppressed in rat erythroid cells. In contrast, heme reduction was not seen in both human erythroid cells when PPO was inhibited. Rats underwent synchronous maturation in primitive erythropoiesis. Our results combined with epidemiological findings that patients with deficient PPO are not anemic led us to conclude that human erythroblasts are resistant to the herbicide. It is suggested that the rat would be an inappropriate model for assessing the developmental toxicity of S-53482 in humans as rats are specifically sensitive to PPO inhibition by the herbicide.

A Spontaneous Oligodendroglioma in the Lumbar Portion of the Spinal Cord in a Young BrlHan:WIST@Jcl (GALAS) Rat.

Oligodendroglioma is a rare tumor originating from oligodendrocytes found mainly in the cerebrum in aged rats. Only a few reports have shown spontaneous occurrence of this tumor in the spinal cord, and no report has mentioned its occurrence in young rats. We encountered a case of spontaneous oligodendroglioma in the lumbar portion of the spinal cord in a young (9 weeks old) female BrlHan:WIST@Jcl (GALAS) rat. Here we report the detailed histopathological and immunohistochemical characteristics of this case. No clinical signs, no gross lesions at necropsy, and no specific changes in hematology or blood biochemistry were observed. The tumor was located in the dorsal funiculus in the lumbar portion of the spinal cord and widely spread to the dorsal root nerve. The neoplastic cells showed a sheet-like growth pattern and had small round nuclei, clear cytoplasm and distinct cell borders that resulted in a honeycomb pattern. No mitotic figures or other histological lesions were observed. The neoplastic cells were positively stained for Olig2 and PCNA. The present case was considered to be a low-grade oligodendroglioma based on the histological and immunohistochemical features. To our knowledge, our case is considered to be extremely rare and the first report in a young rat.

Behavioral laterality and morphological asymmetry in the cuttlefish, Sepia lycidas.

Behavioral laterality is widely found among vertebrates, but has been little studied in aquatic invertebrates. We examined behavioral laterality in attacks on prey shrimp by the cuttlefish, Sepia lycidas, and correlated this to their morphological asymmetry. Behavioral tests in the laboratory revealed significant individual bias for turning either clockwise or counterclockwise toward prey, suggesting behavioral dimorphism in foraging behavior. Morphological bias was examined by measuring the curvature of the cuttlebone; in some the cuttlebone was convex to the right (righty), while in others, the cuttlebone was convex to the left (lefty). The frequency distributions of an index of cuttlebone asymmetry were bimodal, indicating that populations were composed of two types of individuals: "righty" and "lefty." Moreover, an individual's laterality in foraging behavior corresponded with the asymmetry of its cuttlebone, with righty individuals tending to turn counterclockwise and lefty ones in the opposite direction. These results indicate that cuttlefish exhibit behavioral dimorphism and morphological antisymmetry in natural populations. The presence of two types of lateral morph in cuttlefish provides new information on the relationship between antisymmetric morphologies and the evolution of individual laterality in behavioral responses in cephalopods. The implications of these findings for the interpretation of ecological meaning and maintenance mechanisms of laterality in cuttlefish are also discussed.

Oog1, an oocyte-specific protein, interacts with Ras and Ras-signaling proteins during early embryogenesis.

We previously identified an oocyte-specific gene, Oogenesin 1 (Oog1), that encodes 326 amino acids containing a leucine zipper structure and a leucine-rich repeat. In the present study, to identify the interacting proteins of Oog1, we performed a yeast two-hybrid screening using a GV-oocyte cDNA library and found that Ral guanine nucleotide dissociation stimulator (RalGDS) is the binding partner of Oog1. Coimmunoprecipitation assay confirmed the interaction between Oog1 and RalGDS proteins. Colocalization experiments provide the evidence that the nuclear localization of RalGDS depends on the expression of Oog1. Interestingly, RalGDS protein localized in the nucleus rather than the cytoplasm between late 1-cell and early 2-cell stages, the time when Oog1 localizes in the nucleus. We also examined the interaction between Oog1 and Ras by GST pull-down assay and revealed that Oog1 interacts with Ras in a GTP-dependent manner. These findings suggest a role of Oog1 as a Ras-binding protein.

Oogenesin is a novel mouse protein expressed in oocytes and early cleavage-stage embryos.

We describe a new gene (Oogenesin) that is expressed through oogenesis and early embryogenesis in the mouse. De novo expression starts at 15.5 dpc (days postcoitum) in the ovary, which coincides with the start of oogenesis. The isolated cDNA was 1387 base pairs (bp) in length with a single open reading frame of 326 amino acids corresponding to a predicted molecular mass of 37 kDa with no significant homology to previously reported sequences. A remarkable characteristic of the gene is the presence of a leucine zipper structure at amino acid positions 131-152 and a leucine-rich domain at positions 131-254. Northern blot analysis demonstrated that the mRNA was present only in the ovary, in which it was expressed as a single transcript of approximately 1.7 kb. In situ hybridization revealed distinct signals in the oocytes in follicles at all stages (primordial to antral follicles). Western blot analysis demonstrated that the protein is expressed from oocytes to four-cell-stage embryos and that it has a little larger size (46 kDa) than the predicted size of 37. Immunohistochemical analysis of ovary sections revealed that the protein is also expressed specifically in oocytes in follicles at all stages. Furthermore, immunostaining of preimplantation embryos revealed that the protein localizes in nuclei at the late one-cell and early two-cell stages. These results suggest that the gene has some roles in zygotic transcription of early preimplantation embryos as well as folliculogenesis and oogenesis in the mouse.