Biomedical subjects

Akitsugu Morishita

Publications and source records attributed to Akitsugu Morishita.

6 recordsLinked to original sources

PubMed2006

Quantification of distension in rat cerebral perforating arteries.

We developed a novel cerebral angiography procedure for rodents using monochromatic synchrotron radiation X-rays and obtained images of rat cerebral perforating arteries for the first time. In normotensive rat, hypercapnia rapidly distended the perforators between 3 and 15 min after induction and major trunk vessels distended more rapidly in 3-6 min. Systemic hypotension made by stepwise hemorrhage distended the perforators up to 158% of control values but constricted most of the large cerebral trunk vessels. In spontaneous hypertensive rats, systemic hypotension-induced distension disappeared in perforators, indicating that perforators with chronic hypertension lose their autoregulatory distensibility.

Animals↗

PubMed2005

[A case of subacute combined degeneration of the spinal cord diagnosed by characteristic findings of magnetic resonance imaging: case report and review of 22 cases].

Subacute combined degeneration (SCD) is a rare cause of demyelination of the dorsal and lateral columns of the spinal cord, and is a neurogenic complication due to vitamin B12 deficiency. This report concerns a patient with progressive sensory disturbance, but no abnormal neurological findings. A 73-year-old man with gastrectomy presented with a 6-month history of gradually worsening tingling in both hands. Magnetic resonance imaging (MRI) of the cervical spine clearly showed symmetrical high-signal areas on T2WI involving the posterior columns of the cervical cord from C2 through C6. A diagnosis of SCD of the spinal cord was considered and confirmed by laboratory findings. The patient was treated with vitamin B12 supplements and showed gradual improvement in his clinical symptoms. Repeat MRI of the cervical spine after 3 months indicated a slight decrease in the area of the abnormal signal. Among all the possible causes of myelopathy, SCD of the spinal cord, involving neurological complications due to vitamin B12 deficiency, is one of the less often encountered diseases. Nevertheless, SCD should be considered in the differential diagnosis of all spinal cord, peripheral nerve, and neuropsychiatric disorders.

Aged↗

PubMed2004

Improvement of visual acuity caused by opticochiasmal astrocytoma after treatment for associated hydrocephalus--case report.

A 33-year-old male presented with syncopal attacks. He had a history of slowly progressive deterioration of visual acuity in both eyes. His visual deterioration began in the left eye at age 12 years and in the right eye at age 20 years. His left eye was completely blind by age 33 years. He had received no prior treatment for these visual disturbances. Magnetic resonance (MR) imaging on admission showed a large tumor with inhomogeneous intensity occupying the bilateral optic canals and orbital cavities, with extension to parasellar region. Arachnoid cysts were found in the left middle fossa and supracerebellar space, which had caused herniation of the cerebellar tonsils to the foramen magnum. Open biopsy and histology verified that the tumor was pilocytic astrocytoma. Arachnoid cysts associated with the hydrocephalus were treated with a ventriculoperitoneal shunt. Seven years after surgery, visual acuity of the right eye had improved although the left eye remained blind. Follow-up MR imaging demonstrated marked reduction in size of the ventricles and arachnoid cysts, but the tumor size did not change. This case illustrates the benign nature of low-grade glioma in this region in spite of the large size and long history. Deterioration of visual acuity may be reversible in some cases of opticochiasmal astrocytoma. In our case, the improvement in visual acuity probably resulted from growth arrest of the tumor and improvement in the dynamics of cerebrospinal fluid flow.

Adult↗

PubMed2003

Congenital cavernous angioma exhibits a progressive decrease in size after birth.

CASE REPORT: We report a case of congenital intracranial cavernous angioma, which was initially found at a gestational age of 34 weeks in utero as a mass lesion associated with hydrocephalus. After birth, the patient was treated for hydrocephalus first by external drainage and then by ventricular peritoneal shunt. The natural course of the mass lesion was observed until the age of 8 months when the histopathological diagnosis confirmed the cavernous angioma after tissue was obtained by surgery. CT scans repeated monthly during this period demonstrated that the angioma continuously decreased in size. There was no evidence of hemorrhage in the angioma on serial CT scans. The histopathology revealed thrombosis of cavernous vessels with hyaloid changes in the angioma. DISCUSSION: The mechanisms of the decreasing size of the cavernous angioma have often been discussed in relation to spontaneous hemorrhages and resolution. The present case suggests a mechanism in which the spontaneous formation of a thrombus might be the dominant factor for the decrease in size. Thrombus formation may result from low perfusion due to the large size of the angioma.

Brain Neoplasms↗

PubMed2003

Moyamoya syndrome after prophylactic cranial irradiation for acute lymphocytic leukemia.

A 9-year-old boy presented with an episode of syncope, and MR imaging revealed bilateral internal carotid artery stenosis with moyamoya vessel formation. He had had prophylactic cranial irradiation at a total dose of 24 Gy for the treatment of acute lymphocytic leukemia at the age of 4. Following this, he was in a complete state of remission for 6 years. During an observation period of a year after the onset of syncope, MR imaging showed development of multiple ischemic lesions in both hemispheres. He developed a transient ischemic attack of mild motor weakness in his arm and an indirect anastomosis was performed on the severely affected side at the age of 10. Radiation-induced vasculopathies are known to be associated with primary diseases of intracranial tumors, but the frequency is unclear. Ours is the third case in whom prophylactic cranial irradiation for a hematological disorder might have induced cerebral vasculopathies.

Brain Ischemia↗

PubMed2002

[Clinical analysis of pediatric shunt catheter fracture].

Between 1985 and 1998, 415 shunt dysfunctions occurred at Kobe Children's Hospital. The main reasons for shunt revision were obstruction of the catheter, shunt infection, and shunt disconnection. This report presents an analysis of 35 patients (36 cases) who underwent a ventriculoperitoneal (VP) shunt revision because of shunt catheter fracture. All patients were less than 18 years old. We researched their age at the time of revision, site of disruption, postoperative period, shunt system, clinical symptoms, and other factors. The mechanical aspects of shunt catheter fracture are also discussed in this report. The peak time of shunt catheter fracture was the time when children were growing up and were entering elementary school. In other words, when their height was increasing rapidly. At that time, the distal catheter is subjected to traction between the valve and the abdomen at the site of insertion in either the upper or lower direction. However, physical examination of the shunt catheter showed normal range. Additional contributory factors were chronic stimulation at the occipital bone, clavium bone, and costal arch, while movement of the neck and body rotation also caused shunt catheter fracture. These factors all originated from shearing strain at the shunt catheter. We look forward to the introduction of a stronger shunt catheter, because surgical repair time must be minimized to protect the child's mental development. In addition, shearing strain at the shunt catheter needs special attention.

Age Factors↗