Biomedical subjects

Shoko M Yamada

Publications and source records attributed to Shoko M Yamada.

14 recordsLinked to original sources

PubMed2006

Primary malignant B-cell-type dural lymphoma: Case report.

BACKGROUND: The primary malignant dural lymphoma of B-cell type is rare. Our review of the literature (24 cases) indicated that patients with this tumor had female predominance, immunocompetency, and longer survival compared with those with primary malignant intracerebral lymphomas. Based on its clinicopathological features, this dural lymphoma may be classified differently from other types of malignant lymphomas in the central nervous system. CASE DESCRIPTION: The authors report an example of a patient who had a favorable course of malignant dural lymphoma. A 59-year-old woman presented with primary malignant dural lymphoma in the frontal area. Histological diagnosis was a diffuse large B-cell-type lymphoma of intermediate malignancy, but MIB-1 index was extremely high. Subtotal tumor removal was followed by 4 courses of chemotherapy. Thirty months after surgery, the patient is asymptomatic with no MRI evidence of recurrence. A combination of subtotal resection and chemotherapy for a primary malignant dural lymphoma is an effective means to attempt cure of this tumor. CONCLUSION: These rare tumors may be managed successfully by subtotal resection and postoperative treatment. We believe that chemotherapy is the treatment of choice after subtotal resection of malignant dural lymphomas, as experienced in our case.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2006

Clinico-pathological significance of RCAS1 expression in gliomas: a potential mechanism of tumor immune escape.

RCAS1, one of the tumor cell surface antigens, is strongly expressed in aggressive tumors. RCAS1 suppresses the in vitro growth of immune effector cells. We investigated the expression of RCAS1 in 57 gliomas using immunohistochemistry. Furthermore, we examined the association of the RCAS1 expression with the infiltration of tumor infiltrating lymphocyte (TIL). RCAS1 overexpression was significantly correlated with high histological grade and poor prognosis. Reduced infiltration and increased apoptosis of TILs was observed in RCAS1-positive regions. Apoptotsis of TILs appeared to be induced by RCAS1. RCAS1 expression in gliomas may play roles in tumor progression and tumor immune escape.

Adolescent↗

PubMed2005

Double-platinum chemotherapy combined with etoposide in metastatic brain tumor from small cell lung carcinoma.

The platinum-based chemotherapeutic agents, such as cisplatin (CDDP) and carboplatin (CBDCA), are effective for small cell lung carcinoma (SCLC). However, high dose treatment of these agents required for advanced-stage SCLC is often associated with severe toxicity. The authors used combination of lower doses of both cisplatin and carboplatin combined with etoposide (VP-16) to minimize side effects of these agents. This goal was accomplished by utilizing the facts that each agent has its own toxicity that can be controlled individually. Two patients (60- and 71-year old men) with multiple metastatic brain tumors from SCLC were treated by our chemotherapeutic regimen. After fourth chemotherapy, remarkable shrinking of brain masses was associated with significant decrease the size of original lung lesions in both cases. The two patients were discharged without any side effects of the treatment, and neurological deficits subsided in both cases. Each course provided the following schedules: carboplatin 200 mg/m2 x 1 day, cisplatin 25 mg/m2 x 2 days (intravenous administration), and etoposide 25 mg oral x 14 days. After second chemotherapy, the patient of Case 1 was irradiated to both brain and chest lesions, and only to brain in Case 2. The authors concluded from our two cases that the combination of these agents extremely effective to treat this malignancy with less toxicity. We named this double platinum chemotherapy as 'PEC', abbreviated from cisplatin, etoposide, and carboplatin. m

Antineoplastic Agents↗

PubMed2005

A rapidly enlarging nocardial brain abscess mimicking malignant glioma.

Nocardial brain abscesses are uncommon and are not preceded by clear infectious symptoms in most cases. Delayed identification of the bacteria is responsible for a high mortality rate. A 58-year-old afebrile woman was admitted to our hospital because of progressive right hemiparesis and aphasia. Magnetic resonance imaging (MRI) showed a single ring-enhanced lesion in the left frontal lobe. It was extremely difficult to establish the diagnosis of brain abscess, because the laboratory data provided little evidence of bacterial infection, (201)TlCl-scintigraphy revealed definite accumulation of thallium in the lesion, and follow-up MRI demonstrated rapid enlargement of the lesion. Total resection was performed because of the possibility of a malignant brain tumor, but brain abscess was finally diagnosed with histological examination. A nocardial species was detected through microscopic examination of the pus obtained at surgery, and this precise diagnosis of nocardial brain abscess in the early stage enabled the administration of appropriate antibiotics and the patient's quick recovery. Nocardial brain abscesses are often misdiagnosed as malignant brain tumors, and a definitive diagnosis may not be possible without detecting bacteria from the lesion. Total excision of the abscess can produce good results when the abscess is large and located superficially, but incomplete aspiration and drainage of a lesion is associated with a high chance of relapse.

Brain Abscess↗

PubMed2004

Characterization of microglia induced from mouse embryonic stem cells and their migration into the brain parenchyma.

We derived microglia from mouse embryonic stem cells (ES cells) at very high density. Using the markers Mac1(+)/CD45(low) and Mac1(+)/CD45(high) to define microglia and macrophages, respectively, we show that Mac1(+) cells are induced by GM-CSF stimulation following neuronal differentiation of mouse ES cells using a five-step method. CD45(low) expression was high and CD45(high) expression was low on induced cells. We used a density gradient method to obtain a large amount of microglia-like cells, approximately 90% of Mac1(+) cells. Microglia-like cells expressed MHC class I, class II, CD40, CD80, CD86, and IFN-gammaR. The expression level of these molecules on microglia-like cells was barely enhanced by IFN-gamma. Intravenously transferred GFP(+) microglia derived from GFP(+) ES cells selectively accumulated in brain but not in peripheral tissues such as spleen and lymph node. GFP(+) cells were detected mainly in corpus callosum and hippocampus but were rarely seen in cerebral cortex, where Iba1, another marker of microglia, is primarily expressed. Furthermore, both GFP(+) and Iba1(+) cells exhibited a ramified morphology characteristic of mature microglia. These studies suggest that ES cell-derived microglia-like cells obtained using our protocol are functional and migrate selectively into the brain but not into peripheral tissues after intravenous transplantation.

Animals↗

PubMed2004

Pathophysiology of tethered cord syndrome: correlation with symptomatology.

Tethered cord syndrome (TCS) is a stretch-induced functional disorder of the spinal cord. The mechanical cause of TCS is an inelastic structure anchoring the caudal end of the spinal cord that prevents cephalad movement of the lumbosacral cord. Stretching of the spinal cord occurs in patients either when the spinal column grows faster than the spinal cord or when the spinal cord undergoes forcible flexion and extension. Research in patients and experimental animals suggests that there is a link between the clinical dysfunctions that characterize TCS and putative pathophysiological changes that accompany this syndrome. Among these changes are depression of electrophysiological activity and shifts in the reduction/oxidation ratio of cytochrome oxidase. The latter suggests that there is impairment of oxidative metabolism. These putative pathophysiological changes in TCS occur mainly within the lumbosacral cord under excessive tension. The authors discuss the pathophysiology of TCS and examine related symptoms.

Action Potentials↗

PubMed2004

Extracranially extended meningothelial meningiomas with a high MIB-1 index: a report of two cases.

Meningiomas that extend from the meninges to the extracranial tissue and result in skull osteolysis have been known to take an aggressive clinical course. Two such cases in elderly patients are reported. Case 1 is an 82-year-old woman who had undergone removal of the parasagittal meningioma (meningothelial meningioma with 5% of MIB-1 index) 4 years and 6 months previously, developed recurrence of the tumor that extended to extracranial soft tissue. Biopsy obtained from the subcutaneous tissue showed an atypical meningothelial meningioma with 20% of MIB-1 index. In case 2 an 84-year-old man, who developed rapidly progressing dementia and gait disturbance, the MRI study revealed an intracranial-extraaxial right frontal tumor with an extracranial extension resulting in skull osteolysis. Pathological examination of the totally resected tumor identified meningothelial meningioma, but MIB-1 index of the intracranial portion of the tumor was less than 0.1%, while that of the extracranial portion was approximately 15%. Although the meningiomas presently reported failed to show histological features of malignancy, the high MIB-1 index indicated that they were rapidly growing tumors. In the present report it is considered that meningioma cells that invade the skull and extracranial tissue are biologically aggressive and require total resection, as long as the condition of the patients is feasible for surgery.

Aged↗

PubMed2004

Concept of arteriovenous malformation compartments and surgical management.

Cerebral AVMs are known to be a source of intracranial hemorrhages and epileptic seizures. Their natural history indicates approximately 15% mortality and 35% morbidity over a 15-year period. This significant mortality and morbidity mandates a need for satisfactory treatment of this entity, ideally by elimination of AVMs. Microsurgical resection, endovascular embolization and radiosurgery (irradiation) are the three effective modes of treatment currently available. However, no objective criteria have been established for which mode(s) of treatment should be selected for individual patients with AVMs. Considering the complexity of AVMs and variable conditions of individual patients, neurosurgeons, intravascular interventionalists and radiosurgeons must make their own decisions on how to treat each patient based on their experience. In practice, treatment of small AVMs in non-functional areas is favored equally by each of these specialists, while they tend to avoid treatment of large AVMs, particularly those in functional areas of the brain. The authors report the surgical intervention of large AVMs, including those located in functional areas of the hemisphere by special techniques. One can demonstrate AVM compartments by using angiography and with the aid of color Doppler ultrasonography, each compartment can be outlined and dissected individually until all the compartments are isolated without causing any damage to the surrounding brain and the entire AVM is rendered shrunken and then removed. The concept of compartmental treatment of AVMs may be applied in the future to radiosurgery and intravascular embolization of large AVMs.

Arteriovenous Malformations↗

PubMed2004

Adult tethered cord syndrome: relative to spinal cord length and filum thickness.

The adults with tethered cord syndrome (TCS) are divided into two groups: group-1 adult TCS patients with spinal dysraphism; and group-2 patients without dysraphism who develop signs and symptoms in adulthood. A significant number of group-2 patients failed to show elongation of the spinal cord and abnormally thick filum terminale. This paper reports the combinations of the location of the caudal end of the spinal cord and the thickness of the filum terminale in 104 patients with group-2 adult TCS. The caudal end of the spinal cord was found at the L2-3 intervertebral space or above in 37 patients (35.6%) and below L2-3 level in 67 patients (64.4%). The diameter of the filum was <2 mm in 60 patients (57.7%) and > or =2 mm in 44 patients (42.3%). These data clearly indicate that the pre-operative diagnosis of adult TCS must rely primarily on the neurological symptomatology and the specific imaging feature, posterior displacement of the conus and filum that attach the posterior arachnid membrane.

Adolescent↗

PubMed2004

Tethered cord syndrome: overview of diagnosis and treatment.

This article covers the basis of tethered cord syndrome as a stretch-induced spinal cord disorder, including pathophysiology, signs and symptoms, imaging diagnosis, indication for surgical treatment, and surgical procedures. Anomalies that cause mechanical spinal cord tethering are listed, and the surgical untethering technique for each anomaly is described.

Diagnostic Imaging↗

PubMed2004

Symptomatic protocols for adult tethered cord syndrome.

Diagnosis of tethered cord syndrome (TCS) is complicated because anatomical information is not adequate for this task. For example, recent studies have shown that the combination of an elongated cord and a thick filum terminale, demonstrated by MRI or at operation, is no longer an essential feature for the diagnosis of TCS. For TCS diagnosis, emphasis should rather be on its characteristic symptomatology and accentuated by postural changes, since TCS is a functional disorder of the lumbosacral spinal cord. In this report, the authors present the list of signs and symptoms pertinent to TCS in adult and late teenage patients to serve as a diagnostic means.

Diagnosis, Differential↗

PubMed2003

Dissecting aneurysm of the anterior cerebral artery with severe subarachnoid hemorrhage during treatment for cerebral infarction.

Intracranial dissecting aneurysms cause ischemia, but anticoagulation or antiplatelet agents are administered to most ischemic patients without angiographical investigation. A 55-year-old woman succumbed to a subarachnoid hemorrhage (SAH) during antiplatelet therapy for ischemia caused by a dissecting aneurysm at the anterior cerebral artery, which was identified by conventional angiography on day 11 after admission. The authors emphasize that all dissecting aneurysms manifesting ischemic attack can cause hemorrhage. Therefore, emergency angiography is recommended for patients with ischemia complaining of a headache. If dissection is identified, it may be better to regulate the blood pressure of the patient strictly without anticoagulation or antiplatelet therapy.

Aortic Dissection↗

PubMed2002

Fibroblast growth factor receptor (FGFR) 4 correlated with the malignancy of human astrocytomas.

Fibroblast growth factor receptor (FGFR) 4 possesses high affinity to acidic and basic fibroblast growth factors (FGFs). The authors focused on FGFR 4 expression in astrocytoma because the FGF expression increases as the tumor malignancy progresses. Forty-one astrocytoma specimens were examined by immunohistochemistry and polymerase chain reaction-Southern blot. FGFR 4 was negative in all seven Grade II astrocytomas by immunohistochemistry, while positive in four among 15 Grade III and in 13 among 19 Grade IV astrocytomas. The median survival time of Grade III astrocytoma patients was 22.3 months in FGFR 4 negative group and 14.5 months in positive group (p < 0.05). Those of Grade IV patients were 14.2 months in FGFR 4 negative group and 11.9 months in positive group (p > 0.05, not significant). However, FGFR 4 mRNA was detected in all specimens suggesting activated translation system of FGFR 4 in progression of the tumor malignancy. Histologically diagnosed Grade III astrocytoma patients can be divided into two groups; one with median survival time close to those with Grade II astrocytoma patients, and the other similar to that of glioblastoma patients. The authors concluded that FGFR 4 must be an important factor which predicts short survival Grade III astrocytoma patients, who require strict adjuvant therapy in accordance with glioblastoma.

Adolescent↗

PubMed2002

Severe papilledema identified 3 weeks after head injury.

A 62-year-old woman presented with rapidly developed visual disturbance without associated headache or nausea 3 weeks after head injury. Ophthalmologic examination revealed bilateral severe papilledema with retinal hemorrhage, and intracranial pressure (ICP) was 17.5 cmH2O estimated by lumbar puncture. Computed tomography and magnetic resonance (MR) imaging showed no evidence of increased ICP, except dilation of the subarachnoid space around the optic nerves with distortion of the nerves. Her visual acuity remarkably improved after steroid and glycerol treatment, and optic fundus examination revealed bilateral clear optic papillae without atrophic changes. Follow-up MR imaging demonstrated that the bilateral optic nerves had regained the normal appearance. These results indicate that the bilateral papilledema was caused by increased subarachnoid pressure around the bilateral optic nerves. We conclude that papilledema can occur with a mildly increased ICP and trapped subarachnoid cerebrospinal fluid around the optic nerves, and papilledema may progress after the ICP is normalized. Papilledema is a warning sign for increased ICP, associated with future visual loss from retinal hemorrhage. Therefore, repeated funduscopic investigation is necessary for the early diagnosis and treatment of papilledema.

Aged↗