Effect of draxin knockdown on the projection of 23C10-positive neural fibers in the embryonic chick hindbrain / 解剖学报

[Abstract] Objective To investigate the effects of the downregulation of draxin expression on the projection characteristics of 23C10-positive neural fibers in the chick embryonic hindbrain. Methods The vitro incubation of HH stages 21-22 chick embryonic hindbrain biopsy with alkaline phosphatase (ALP) protein was used as control group. The incubation of HH stages 21-22 chick embryonic hindbrain biopsy with draxin-ALP fusion protein was used as experimental group. The number of embryonic hindbrain for each group was 10. To detect whether 23C10-positive neural fibers could directly bind to draxin protein or not;In ovo electroporation using empty vector in the chick embryonic hindbrain was used as control group. In ovo electroporation with small interfering RNA(siRNA) expressing vector for reducing draxin expression in the chick embryonic hindbrain was used as experimental group. The number of embryonic hindbrain for each group was 18. The effect of the down-regulation of draxin expression and the change of projection characteristics of 23C10-positive neural fibers were observed to check whether the down-regulation of draxin expression would affect the distribution of 23C10-positive fibers. Results Most portion of draxin protein could overlap with 23C10-positive neural fibers in HH stages 21-22 chick embryonic hindbrain biopsies; After expression of the siRNA plasmid against draxin by electroporation, the expression level of draxin protein was significantly reduced, and the distribution of 23C10-positive fibers was scattered in the dorsal hindbrain on the electroporated side at HH stages 25-26 of chick embryos (P < 0. 05) . Conclusion Draxin protein may directly bind to 23C10-positive fibers in hindbrain, and it plays an important regulatory role in the fasciculation of 23C10-positive fibers during chick embryonic development.

Management of Chiari I Deformity in Children and Adolescents: A Report from the Consensus Taskforce of the Brazilian Society of Pediatric Neurosurgery

Much controversy remains on the current management of Chiari I deformity (CID) in children, with many clinical, surgical and ethic-legal implications. The Brazilian Society of Pediatric Neurosurgery (SBNPed, in the Portuguese acronym) has put together a panel of experts to analyze updated published data on the medical literature about this matter and come up with several recommendations for pediatric neurosurgeons and allied health professionals when dealing with CID. Their conclusions are reported herein, along with the respective scientific background.

Surgical Outcome of Adult Idiopathic Chiari Malformation Type 1

OBJECTIVE: The pathophysiology of idiopathic Chiari malformation (CM) type 1 is disturbance of free cerebrospinal fluid (CSF) flow and restoration of normal CSF flow is the mainstay of treatment. Additional migration of the medulla oblongata in pediatric patients is referred to as CM type 1.5, but its significance in adult patients is unknown. This study is to compare surgical outcomes of adult idiopathic CM type 1.5 with that of type 1. METHODS: Thirty-eight consecutive adult patients (M : F=11 : 27; median, 33.5; range, 18–63) with syringomyelia due to idiopathic CM type 1 were reviewed. Migration of the medulla oblongata was noted in 13 patients. The modified McCormick scale (MMS) was used to evaluate functional status before and one year after surgery. All patients underwent foramen magnum decompression and duroplasty. Factors related to radiological success (≥50% decrease in the diameter of the syrinx) were investigated. The follow-up period was 72.7±55.6 months. RESULTS: Preoperative functional status were MMS I in 11 patients and MMS II in 14 of CM type 1 and MMS I in 8 and II in 5 of CM type 1.5. Of patients with MMS II, 5/14 patients in group A and 3/5 patients in group B showed improvement and there was no case of deterioration. Radiological success was achieved in 32 (84%) patients and restoration of the cisterna magna (p=0.01; OR, 46.5) was the only significant factor. CONCLUSION: Migration of the medulla oblongata did not make a difference in the surgical outcome when the cisterna magna was restored.

Role of α2-adrenoceptors in the lateral parabrachial nucleus in the control of body fluid homeostasis

Central α2-adrenoceptors and the pontine lateral parabrachial nucleus (LPBN) are involved in the control of sodium and water intake. Bilateral injections of moxonidine (α2-adrenergic/imidazoline receptor agonist) or noradrenaline into the LPBN strongly increases 0.3 M NaCl intake induced by a combined treatment of furosemide plus captopril. Injection of moxonidine into the LPBN also increases hypertonic NaCl and water intake and reduces oxytocin secretion, urinary sodium, and water excreted by cell-dehydrated rats, causing a positive sodium and water balance, which suggests that moxonidine injected into the LPBN deactivates mechanisms that restrain body fluid volume expansion. Pretreatment with specific α2-adrenoceptor antagonists injected into the LPBN abolishes the behavioral and renal effects of moxonidine or noradrenaline injected into the same area, suggesting that these effects depend on activation of LPBN α2-adrenoceptors. In fluid-depleted rats, the palatability of sodium is reduced by ingestion of hypertonic NaCl, limiting intake. However, in rats treated with moxonidine injected into the LPBN, the NaCl palatability remains high, even after ingestion of significant amounts of 0.3 M NaCl. The changes in behavioral and renal responses produced by activation of α2-adrenoceptors in the LPBN are probably a consequence of reduction of oxytocin secretion and blockade of inhibitory signals that affect sodium palatability. In this review, a model is proposed to show how activation of α2-adrenoceptors in the LPBN may affect palatability and, consequently, ingestion of sodium as well as renal sodium excretion.

Suboccipital craniectomy with opening of the fourth ventricle and duraplasty: study of 192 cases of craniovertebral malformations / Descompressao da fossa posterior sem tonsilectomia em 192 casos de impressao basilar, malformacao de Chiari e/ou siringomielia

The prime objective in the surgical treatment of basilar impression (BI), Chiari malformation (CM), and/or syringomyelia (SM) is based on restoration of the normal cerebrospinal fluid (CSF) dynamics at the craniovertebral junction and creation of a large artificial cisterna magna, avoiding the caudal migration of the hindbrain. It is observed that a large craniectomy might facilitate an upward migration of the posterior fossa structures. There are many surgical techniques to decompress the posterior fossa; however, a gold standard approach remains unclear. The authors present the results of 192 cases of BI, CM, and SM treated between 1975 and 2008 and whose surgical treatment was characterized by a large craniectomy without tonsillectomy with the patient in the sitting position, large opening of the fourth ventricle, and duraplasty.

O principal objetivo no tratamento cirúrgico da impressão basilar, malformação de Chiari e/ou siringomielia fundamenta-se na restauração da dinâmica do líquido cefalorraqueano ao nível da transição craniovertebral e criação de cisterna magna ampla. Isto é fator importante para evitar a migração caudal das estruturas da fossa posterior. A craniectomia ampla facilita a migração cranial dessas estruturas. Existem várias técnicas cirúrgicas para descomprimir a fossa posterior, mas não há evidência sobre qual a melhor.. Os autores apresentam os resultados de 192 casos de impressão basilar, malformação de Chiari e siringomielia, operados entre 1975 e 2008, nos quais o tratamento cirúrgico se baseou em ampla craniectomia com o paciente em posição sentada, sem tonsilectomia, abertura ampla do quarto ventrículo e enxerto dural.

A Case of Rhombencephalitis Presented with Intractable Hiccup / 대한소아신경학회지

The term 'rhombencephalitis' refers to inflammatory diseases affecting the hindbrain. We experienced a case of rhombencephalitis in a 14 years old girl, who presented with fever, headache, and intractable hiccup for one week prior to admission. Brain MRI on admission showed bilateral high signal intensities in the dorsal portion of the medulla oblongata on T2WI and FLAIR. Examination of cerebrospinal fluid showed increased WBC count (33/mm3, Lymphocyte 81%), normal protein and glucose level. Immunoserologic study showed decreased C3, C4 level and increased Anti-ds DNA level. However, FANA was negative. The hiccup was controlled by administration of IVIG (1 g/kg/day for 2 days) and steroid (30 mg/kg/day for 3days) without any neurologic symptoms. We report a case with the brief review of related literatures.

Posterior fossa decompression with tonsillectomy in 104 cases of basilar impression, Chiari malformation and/or syringomyelia / Descompressão da fossa posterior com tonsilectomia em 104 casos de impressão basilar, malformação de Chiari e/ou siringomielia

The prime objective in the surgical treatment of basilar impression (BI), Chiari malformation (CM) and/or syringomyelia (SM) is based on the restoration of the normal cerebrospinal fluid (CSF) dynamics at the craniovertebral junction through the creation of a large artificial cisterna magna. A small suboccipital craniectomy has been emphasized to avoid caudal migration of the hindbrain structures into the vertebral canal. Nevertheless, the results showed downward migration of the hindbrain related to that type of craniectomy. The authors present, otherwise, the results of 104 cases of BI, CM and/or SM, whose surgical treatment was characterized by a large craniectomy with the patient in the sitting position, tonsillectomy, large opening of the fourth ventricle and duraplasty with creation of a large artificial cisterna magna. A significant upward migration of the posterior fossa structures was detected by postoperative magnetic resonance imaging.

O principal objetivo no tratamento cirúrgico da impressão basilar, malformação de Chiari e/ou siringomielia fundamenta-se na restauração dinâmica do líquido cefalorraqueano ao nível da transição craniovertebral e criação de ampla cisterna magna. Uma craniectomia suboccipital de pequenas dimensões foi proposta para evitar a migração caudal de estruturas rombencefálicas no canal vertebral. Entretanto, os resultados evidenciaram migração caudal do rombencéfalo. Os autores apresentam, por outro lado, os resultados de 104 casos de malformação de Chiari e/ou siringomielia, nos quais o tratamento cirúrgico se baseou em ampla craniectomia com o paciente em posição sentada, tonsilectomia, abertura ampla do quarto ventrículo e enxerto dural com consequente criação de ampla cisterna magna. Uma significante migração cranial das estruturas da fossa posterior foi detectada pelo emprego pós-operatório da ressonância magnética.

Retrospective study of patients with Chiari: malformation submitted to surgical treatment / Estudo retrospectivo de pacientes com malformação de Chiari tratados cirurgicamente

The Chiari malformation (CM) is characterized by variable herniation of one or both cerebellar tonsils, associated or not with displacement of the hindbrain structures into the vertebral canal. This is a retrospective study of 29 patients with CM submitted to surgical procedure between 1990 and 2003. There were 14 females and 15 males whose ages ranged from 16 to 65 years. There were seven patients with isolated CM, 12 associated with syringomyelia (SM), three associated with basilar impression (BI) and seven associated with SM and BI. The surgery was based on posterior fossa decompression. In seven patients a catheter was introduced from the subarachnoid space into the III ventricle and five were submitted to tonsillectomy. Twenty-one patients improved, one worsened, one remained unchanged, four missed follow up and two died. We conclude that the best results with CM surgery are obtained by an effective posterior fossa decompression. Those CM cases associated with other abnormalities, such as SM and BI, probably need complementary techniques which will be the theme for new prospective studies.

A malformação de Chiari (MC) é o deslocamento variável de uma ou ambas as tonsilas cerebelares para o canal vertebral. Este trabalho é um estudo retrospectivo de pacientes com MC tratados com cirurgia de 1990 até 2003. Foram analisados 29 prontuários, sendo 15 pacientes do sexo masculino e 14 do feminino, com idade variando entre 16 a 65 anos. Destes, sete só apresentavam MC, 12 tinham MC associada com siringomielia (SM), três associada com impressão basilar (IB) e sete associada com SM e IB. Foi realizada descompressão da fossa posterior e plástica da dura-máter em todos. Em sete pacientes, foi acrescida a colocação de catéter do espaço subaracnóideo para o interior do IV ventrículo e em cinco a tonsilectomia. Ocorreu melhora dos sintomas em 21 pacientes, um permaneceu inalterado, houve piora em um caso, quatro não tiveram seguimento e dois faleceram. Conclui-se que a boa evolução da MC está relacionada com a descompressão efetiva da fossa posterior. Os casos de MC associadas a outras malformações, como IB e SM, talvez necessitem variações técnicas, as quais serão temas de novos estudos prospectivos.

Expression of D-type cyclins in differentiating cells of the mouse spinal cord

The D-type cyclins form complexes with the cyclin dependent (CD) kinases CDK4 and CDK6 and promote the G1-S phase transition of the cell cycle by antagonizing the retinoblastoma suppresser protein pRB. In the developing nervous system D-type cyclins show spatially and temporally dynamic patterns of expression. We demonstrated that cyclin D1 was transiently expressed in differentiating spinal cord ventral interneurons while cyclin D3 protein was expressed in differentiating motor neurons and dorsal interneurons. This expression of cyclin D3 in neurons of the mantle zone was extended to all regions of the spinal cord at E15.5. The results suggest that cyclin D1 and D3 have specific functions in differentiating neurons. Similarly, in the developing midbrain-hindbrain region the D-type cyclins were expressed in different subsets of cells. Our results argue in favor of different functions for D-type cyclins during proliferation and differentiation of neural progenitors.