Masami Yoshino

Statocyst control of the uropod movement in response to body rolling in crayfish

Summary1.The steering movement of crayfish uropods in response to body rolling was analysed quantitatively.2.The uropod on the upper side is spread out while the other one on the lower side is closed. Opening of one uropod was always accompanied by closing of the other. Positional changes of both uropods in response to body rolling were measured at 13 body positions. The response curve followed an approximate sine function in an intact animal3.In a single-statocyst animal, increase of receptor activity in the intact statocyst caused opening of the ipsilateral uropod and closing of the contralateral one, while decrease of receptor activity had no effect on the uropod position.4.A response curve obtained by algebraic summaion of two response curves in the animals with right and left statolith removed respectively was consistent with that of an intact animal with both statocysts.5.It was concluded that each statocyst can produce bilateral uropod movement only in a limited range of roll angle since the receptor activity increases only when the statocyst hairs are deflected toward the inside of the sensory crescent. Bilateral uropod movement in an intact animal is produced by simple summation of inputs from the right and left statocysts.6.Unilateral statolith removal caused an asymmetrical configuration of the uropods in the resting (0°) body position. The uropod on the operated side opened and that on the opposite side closed. This asymmetry was normalized day by day and the original symmetrical configuration was finally restored about 7 days after operation.

Hirschsprung's disease, acrocallosal syndrome, and congenital hydrocephalus: report of 2 patients and literature review

The L1 cell adhesion molecule (L1CAM) protein is found primarily in the nervous system and is important in neuronal adhesion, migration, neurite outgrowth, and myelination. It is extremely rare that Hirschsprungs disease (HSCR) merges with a disorder showing abnormality of the L1CAM genes such as acrocallosal syndrome (ACS) or X-linked hydrocephalus (XLH). Herein, we report 2 cases--the first showed abnormality of the L1CAM genes and developed HSCR; and the second, with clinically suspected XLH, was successfully operated on for HSCR. When a patient with ACS or XLH presents with constipation, we must consider HSCR in the differential diagnosis, and early treatment is important. Furthermore, it is desirable to select a line treatment of HSCR to prevent infection of the ventriculoperitoneal shunt if the patient requires it.

Frontofacial monobloc advancement using gradual bone distraction method

For children with craniosynostosis presenting intracranial hypertension and facial hypoplasia, different techniques have been used. Commonly, an initial frontoorbital advancement to expand a tight cranium volume was followed by Le Fort III osteotomy to repair midface abnormalities several months later. The 2-stage surgeries were unified into a 1-step procedure to optimize treatment. We here report results of frontofacial monobloc advancement, applying gradual distraction by a rigid external distraction device. Three patients were treated with excellent functional and cosmetic outcome with high rate of patient satisfaction. There was no remarkable complication.

Interspecific Differences in Crustacean Homologous Behavior: Neural Mechanisms Underlying the Reversal of Uropod Steering Movement

SummaryRolling of the body in the same direction induces an asymmetrical steering movement of uropods in the opposite directions in two closely related species of crayfish. InProcambarus clarkii the uropod on the upper side is spread out and closed on the lower side, whereas inCambaroides japonicus the uropod moves in the opposite direction. The stimulus detector, the statocysts, the effector, the uropod musculature, are neither structurally nor functionally significantly different in the two species. The results indicate that the opposite responses could be ascribed to differences in the interneuronal connections within the central nervous system of these two species.

Radiological findings and clinical course of conus lipoma: implications for surgical treatment.

OBJECTIVEA significant variety in morphology of conus lipomas may underlie differences in clinical presentation of the patients and controversy in surgical management. We retrospectively studied 58 patients with conus lipomas at our institutions. The purpose of this study was to infer the clinical course from the radiological findings and to provide information for decision-making in planning for surgical treatment. METHODSThe patients underwent untethering surgery between 1984 and 2005. There were 35 transitional and 23 dorsal lipomas. The age at surgery ranged from 1 month to 50 years (median, 4 yr). Preoperative clinical history, radiological findings, and postoperative results were analyzed. RESULTSFifteen patients were asymptomatic, and 43 patients were symptomatic preoperatively. Twenty-one patients presented with motor deficits of the lower extremities. In seven patients, motor deficits appeared early, before 1 year of age. Massive lipomas compressing the cord or herniation of the spinal cord into the subcutaneous tissue were characteristic findings of such early deterioration. Motor deficits were present in 73% of patients with lipomas extending to the lumbar level, whereas 88% of patients with lipomas confined to the sacral level had only urinary deficits. During a mean postoperative follow-up period of 7.9 years, 4 (27%) of the 15 asymptomatic patients developed urinary and/or motor deficits, and 12 (28%) of the 43 symptomatic patients showed further neurological deterioration. CONCLUSIONThis study demonstrates that the location and morphology of conus lipomas influence the neurological presentation of the patients. Early prophylactic surgery is a reasonable treatment option if early deterioration is predicted by imaging studies.

Calcified vestibular schwannoma in the cerebellopontine angle.

Although vestibular schwannoma is a common tumor in the cerebellopontine angle, calcified vestibular schwannoma is rare. A 59-year-old woman with sudden onset epileptic seizures, was referred to Hokkaido Neurosurgical Memorial Hospital. Neurological examination revealed left Bruns nystagmus, left deafness and left cerebellar ataxia. Brain MRI revealed a mass, about 3cm in diameter, in the left cerebellopontine angle. The mass showed heterogeneous intensity on T1- and T2-weighted and fluid-attenuated inversion recovery (FLAIR) images. Hydrocephalus was seen. On CT scan, the tumor was calcified. Preoperatively, vestibular schwannoma, meningioma, cavernous hemangioma, or thrombosed giant aneurysm were considered as differential diagnoses. The pathological diagnosis was schwannoma. For a calcified mass in the cerebellopontine angle, vestibular schwannoma should be considered in the differential diagnosis to plan appropriate treatment strategies.

A case of cavernous angioma in the septum pellucidum

A 44-year-old man was admitted to Hokkaido Neurosurgical emorial Hospital because of memory disturbance. Eleven months efore admission, a hematoma in the septum pellucidum was ncidentally found on MRI in another hospital, which performed ollow-up for another asymptomatic cavernous angioma in the eft putamen. Because the hematoma was asymptomatic, he was ollowed up at an outpatient clinic. However, eight months after emorrhage, he noticed memory disturbance, and MRI revealed ngioma growth. He was referred to our hospital for surgery. He could not recall events that had happened a few minutes efore. MRI revealed a hematoma localizing in the septum pelluidum (Fig. 1) and a cavernous angioma with venous angioma in he left putamen. The lesion was completely removed through an anterior trancallosal approach. The hematoma was confined to the septum ellucidum, and there was no hematoma in the ventricle.

Small but Severe Residual Hypoperfusion Relates to Symptomatic Hemorrhage Even after Early Perfusion Improvement in Tissue Plasminogen Activator Therapy

Case Report A 70-year-old man who did not take any regular medication presented at the emergency room 73 min after the sudden onset of an impaired level of consciousness, dysarthria, left-sided hemiparesis and left-sided neglect. His NIHSS (National Institutes of Health Stroke Scale) score was 16. His blood pressure was 121/87 and his laboratory data showed glucose 126 mg/dl, a platelet count of 192,000/mm 3 and normal liver and kidney function. DWI showed small ischemic changes in the head of the right caudate nucleus, the periventricular area and the frontal cortical area ( fig. 1 a). MR angiography revealed occlusion of the M1 segment of the right-middle cerebral artery (MCA) ( fig. 1 b). Since the head of the caudate nucleus is usually supplied by the recurrent artery of Heubner, in addition to MCA, branches of the right anterior cerebral artery were thought to be occluded. After confirming that the patient met all eligibility criteria for tPA therapy, administration of a total dose of 0.6 mg/kg tPA with 10% of the dose given as a bolus was started at 140 min after onset according to the directions for the use of tPA in Japan. His symptoms improved from 30 min after the start of the tPA infusion and his NIHSS score was 7 by the end of it. 99m Tc-ethyl cysteinate dimer SPECT imaging 1 h after the end of the tPA infusion revealed a mild hypoperfusion in the cortex of the right MCA territory and a small but severe hypoperfusion in the head of the right caudate nucleus ( fig. 1 c, d). The early clinical improvement and the SPECT findings suggest that early perfusion improvement due to an increase in collateral flow or partial recanalization occurred in the MCA territory except for in the right caudate nucleus. Although posttreatment vital signs and the neurological status were uneventful, Background Symptomatic intracerebral hemorrhage (sICH) is the most unfavorable complication arising after intravenous tissue plasminogen activator (tPA) therapy. In multivariate analyses of sICH after tPA therapy, a high serum glucose level [1] , a large diffusionweighted imaging (DWI) lesion volume [2] and late reperfusion after persistent arterial occlusion [3] are regarded as independent predictors; however, we encountered a tPA-treated patient with sICH, which was not applicable to the above predictions. We present this case and discuss a relationship between the development of sICH and findings of early posttreatment single-photon emission computed tomography (SPECT). Published online: December 1, 2012

Localized reversible high signal intensities on diffusion-weighted MRI in hypoglycemia: A study of 70 cases.

Introduction: It is well-known that localized reversible high signal intensities in the splenium of the corpus callosum or the basal ganglia appear on diffusion-weighted MRI in the presence of hypoglycemia. The aim of this study was to clarify the incidence and significance of such high signal intensity lesions. Results: We analyzed 70 cases of hypoglycemia with consciousness disturbance referred to our outpatient office. Localized reversible high signal intensities on diffusion-weighted MRI were noted in 6 cases (8.6%). They were at the splenium of the corpus callosum in four cases (5.7%), and right frontal cortex and bilateral frontal white matter in one each. Convulsions were noted in five cases, and right hemiparesis was noted in three. None of the three cases of hemiparesis showed localized reversible high signal intensities on diffusion-weighted MRI. These lesions are reversible if the patients undergo treatment without delay. Conclusion: The significance of these lesions is still unclear. However, when a high signal intensity lesion that is not reasonable for the symptom is detected on diffusion-weighted MRI, an immediate check of the blood sugar level is mandatory.