Neuronal Polarity: Positive and Negative Feedback Signals

Establishment and maintenance of neuronal polarity are critical for neuronal development and function. One of the fundamental questions in neurodevelopment is how neurons generate only one axon and several dendrites from multiple minor neurites. Over the past few decades, molecular and cell biological approaches have unveiled a large number of signaling networks regulating neuronal polarity in cultured hippocampal neurons and the developing cortex. Emerging evidence reveals that positive and negative feedback signals play a crucial role in axon and dendrite specification. Positive feedback signals are continuously activated in one of minor neurites and result in axon specification and elongation, whereas negative feedback signals are propagated from a nascent axon terminal to all minor neurites and inhibit the formation of multiple axon, thereby leading to dendrite specification, and maintaining neuronal polarity. This current insight provides a holistic picture of the signaling mechanisms underlying neuronal polarization during neuronal development. Here, our review highlights recent advancements in this fascinating field, with a focus on the positive, and negative feedback signals as key regulatory mechanisms underlying neuronal polarization

コウカセイ エシセイ ジュウカクエン オ ハッショウ シタ カガク チシ シュウイエン ノ 1レイ

We present a case of pericoronitis of lower wisdom tooth leading to descending necrotizing mediastinitis. A 52-year-old man visited our hospital because of swelling and pain in buccal region on the right side in spite of chemotherapeutics at a practicing physician, whose diabetic nephropathy had been treated with dialysis treatment by the same physician. Orthopantomography elucidated an impacted wisdom tooth of the right side mandible and osteosclerosis around there. CT revealed inflammatory thickening of subcutaneous fat tissue from buccal to cervical region. In the blood examination, the values of WBCs, RBCs, platelets, CRP, AST, LDH, TG, BUN, creatinine, GLU, K and Ca increased abnormally, while those of hemoglobin, MCV，MCH，MCHC, albumin, Cl, decreased extraordinarily. Immediate medication of antibiotics was worked out under a clinical diagnosis of pericoronitis of lower wisdom tooth, periostitis of the mandible and cervical cellulitis. Nevertheless, rapid inflamation progressed downward; mediastinal abscess was found by CT image taken 6 days later from the beginning of the therapy. Immediately, extraction of pathogenic teeth, cervical drainage, and transcervical and transthoracic mediastinal drainage were performed under a diagnosis of descending necrotizing mediastinitis. Moreover, bacterial examination was performed using a pus specimen derived from abscess; α-Streptococcus and Prevotella intermedia were detected. CT taken 2 weeks later from the beginning of the therapy revealed continuing bilateral pleural and pericardial effusion in spite of intensive care. Unfortunately he was died of multi organ failure caused by septic shock a month later from the beginning of the therapy

イチジルシイ コツキュウシュウ オ トモナッタ シセイ ジョウガクドウエン ノ 1レイ

We present a case of odontogenic maxillary sinusitis with marked perisinuous bone resorption. A 29-year-old man visited to our hospital because of pain in buccal region on left side after extraction of teeth at a dental practitioner. Orthopantomography and CT were performed and revealed inflammatory thickening of maxillary sinus mucosa and marked perisinuous bone resorption. In the blood examination, the values of WBCs and CRP were elevated abnormally. Moreover, bacterial examination was performed using the exudate from maxillary sinus through a fistula after extraction of teeth; α-Streptococcus, Prevotella buccae, Prevotella intermedia, Prevotella melaninogenica and Acinetobacter baumannii were detected. First, medication of antibiotics and irrigation of maxillary sinus was worked out under a clinical diagnosis of odontogenic maxillary sinusitis. These therapies didn't change perisinuous bone resorption for the better. Sequestrum and mucosa of maxillary sinus were biopsied to examine thoroughly; diagnosis of odontogenic maxillary sinusitis was confirmed histopathologically. Moreover, biochemical examination of blood showed normal serum level of specific markers for bone metabolism or Aspergilli. The similar therapies were continued from then and perisinuous bone resorption stopped suddenly for unknown reasons 3 months after these therapies. Time course of perisinuous bone regeneration was found by CT. Finally, operation to close the antrooral fistula with palatal flap was performed. There has been no relapse of inflammation for more than 5 years

Malignant Lymphoma in the Parasellar Region

The entity of pituitary (sellar or parasellar) lymphoma includes primary pituitary lymphoma (PPL) and secondary pituitary lymphoma (SPL). The latter has an involvement of systemic lymphoma. Both of these lymphomas are extremely rare. We describe a patient with SPL showing a good prognosis. A 78-year-old woman presented with diplopia, left ptosis, and back pain. Magnetic resonance (MR) imaging revealed a parasellar mass lesion extending to the upper clivus and another mass lesion with compression fracture of the Th3 vertebral body. Transsphenoidal exploration was performed, and it showed diffuse large B-cell lymphoma. Based on the positive tumor cells in the following bone marrow aspiration and hepatosplenomegaly in computed tomography (CT) findings, this patient was diagnosed as having a pituitary involvement of systemic lymphoma. After chemotherapy, she achieved complete remission for 4 years. The entity of pituitary lymphoma is extremely rare. Nineteen cases of PPL and 16 cases of SPL have been reported. Generally, clinical and radiological diagnosis was difficult because there are no specific findings. Therefore, biopsy was necessary in all of the cases. T2 hypointensity of a lesion in MR imaging in addition to an elevated serum level of soluble interleukin-2 receptor (sIL-2R) in a patient with a sellar lesion can be useful clues for the differential diagnosis of this rare disease

Correlations of Vascular Architecture and Angiogenesis with Pituitary Adenoma Histotype

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor in solid tumors. However, its role in angiogenesis in pituitary adenoma is controversial. Angiogenesis in solid tumors including pituitary adenoma is commonly evaluated by microvascular density (MVD). Here, we evaluated MVD and the role of VEGF in vascular architecture in 51 pituitary adenomas (24 nonfunctioning, 13 prolactin-secreting, 10 growth hormone-secreting, 3 adrenocorticotropic hormone-secreting, and 1 thyroid-stimulating hormone-secreting). Paraffin sections were stained with CD34 and VEGF. MVD and vascular architecture parameters (vessel area, diameter, perimeter, and roundness) were evaluated in CD34-stained sections. Immunohistochemistry showed 27/51 tumors (53%) were VEGF-positive. There were no significant differences in MVD, any vascular parameter, or adenoma volume between VEGF-positive and VEGF-negative tumors. VEGF mRNA expression was significantly higher in VEGF-positive tumors. There were no significant correlations between VEGF mRNA expression and MVD or vascular parameters. However, vessel diameter and perimeter were significantly larger in prolactin-secreting than nonfunctioning and growth hormone-secreting macroadenomas. The difference in vessel diameter was observed among both VEGF-positive and all adenomas (micro- and macroadenoma). Thus, VEGF may have limited roles in the development of vascular architecture and tumor angiogenesis in pituitary adenomas, but the differences in vessel architecture by histotype (i.e., larger vessel diameter and perimeter in prolactin-secreting adenomas) suggest the hormonal regulation of vessel architecture rather than angiogenesi

Multiple phosphorus chemical sites in heavily phosphorus-doped diamond

We have performed high-resolution core level photoemission spectroscopy on a heavily phosphorus (P)-doped diamond film in order to elucidate the chemical sites of doped-phosphorus atoms in diamond. P 2p core level study shows two bulk components, providing spectroscopic evidence for multiple chemical sites of doped-phosphorus atoms. This indicates that only a part of doped-phosphorus atoms contribute to the formation of carriers. From a comparison with band calculations, possible origins for the chemical sites are discussed

バッシゴ シュッケツ オ ケイキ ニ シンダン サレタ コウレイシャ ニオケル センテンセイ ケツユウビョウ A ﾉ 1レイ

Hemophilia A is often diagnosed by gingival change, traumatic injuries, or bleeding after extraction in childhood, but rarely in senior age. We experienced that a 66 year-old man was diagnosed as hemophilia A by bleeding after tooth extraction. He was referred to our hospital for control the bleeding after tooth extraction. Although we tried to stop bleeding by local hemostasis, we repeated to bleed several times. Then we examined the level of hemorrhage factors. As a result, the patient was diagnosed as moderate hemophilia A, and he received recombinant factor VIII intravenously. After that, the bleeding had been stopped completely