Biomedical subjects

S Nishio

Publications and source records attributed to S Nishio.

At least 73 records · Page 4Linked to original sources

PubMed2000

Ischemic tolerance in the rat neocortex following hypothermic preconditioning.

OBJECT: Ischemic neuronal damage associated with neurological and other types of surgery can have severe consequences for functional recovery after surgery. Hypothermia administered during and/or after ischemia has proved to be clinically beneficial and its effects often rival or exceed those of other therapeutic strategies. In the present study the authors examined whether transient hypothermia is an effective preconditioning stimulus for inducing ischemic tolerance in the brain. METHODS: Adult rats were subjected to a 20-minute period of hypothermic preconditioning followed by an interval ranging from 6 hours to 7 days. At the end of this interval, the animals were subjected to transient focal ischemia induced by clamping one middle cerebral artery and both carotid arteries for 1 hour. The volume of cerebral infarction was assessed 1 or 7 days postischemia. In the first series of experiments, hypothermic preconditioning (28.5 degrees C) with a postconditioning interval of 1 day reduced the extent of cerebral infarction measured 1 and 7 days postischemia. In the second series, hypothermic preconditioning (31.5 degrees C) with postconditioning intervals of 6 hours, 1 day, or 2 days (but not 7 days) reduced the extent of cerebral infarction measured 1 day postischemia. Treatment with the protein synthesis inhibitor anisomycin blocked the protective effect of hypothermic preconditioning. In a final series of experiments, in vitro brain slices prepared from hypothermia-preconditioned (nonischemic) animals were shown to tolerate a hypoxic challenge better than slices prepared from unconditioned animals. CONCLUSIONS: These findings indicate that hypothermic preconditioning induces a form of delayed tolerance to focal ischemic damage. The time course over which tolerance occurs and the ability of a protein synthesis inhibitor to block tolerance suggest that increased expression of one or more gene products is necessary to establish tissue tolerance following hypothermia. The attenuation of hypoxic injury in vitro following in vivo preconditioning indicates that tolerance is due, at least in part, to direct effects on the brain neuropil. Hypothermic preconditioning could provide a relatively low-risk approach for improving surgical outcome after invasive surgery, including high-risk neurological and cardiovascular procedures.

Animals↗

PubMed2000

Gamma knife radiosurgery as a primary treatment for prolactinomas.

OBJECT: The purpose of this study was to estimate the efficacy of gamma knife radiosurgery (GKS) in controlling tumor growth and endocrinopathy associated with prolactinomas. METHODS: Between 1993 and 1997, 164 of 469 patients with pituitary adenomas treated by GKS harbored prolactinomas. The dose to the tumor margin ranged from 9 to 35 Gy (mean 31.2 Gy), and the visual pathways were exposed to a dose of less than 10 Gy. The mean tumor diameter was 13.4 mm. The mean follow-up time for 128 cases was 33.2 months (range 6-72 months). Tumor control was observed in all but two patients who underwent surgery 18 and 36 months, respectively, after GKS. Clinical cure was achieved in 67 cases. Clinical improvement was noted with a decrease in the hyperprolactinemia after GKS. Nonetheless, in 31 (29%) of 108 patients who were followed for more than 2 years no improvement in serum prolactin levels was demonstrated, although this could be normalized by bromocriptine administration after treatment. Nine infertile women became pregnant 2 to 13 months after GKS and all gave birth to normal children. There was no visual deterioration related to GKS. Five women experienced premature menopause. In these patients there was subtotal disappearance of the tumor and an empty sella developed. CONCLUSIONS: Gamma knife radiosurgery as a primary treatment for prolactinomas can be safe and effective both for controlling tumor growth and for normalization of prolactin hypersecretion. A higher margin dose (> or = 30 Gy) seemed to be associated with a better clinical outcome. Gamma knife radiosurgery may make prolactinomas more sensitive to the bromocriptine.

Humans↗

PubMed2000

[Neoadjuvant chemotherapy with cisplatin and CPT-11 for advanced cervical cancer].

Neoadjuvant chemotherapy (NAC) is currently used for the treatment of advanced cervical cancer by many institutions. We investigated the value of NAC followed by radical surgery and/or radiotherapy for patients with locally advanced cervical cancer. Sixteen patients with stage Ib2-IIIb cervical cancer were enrolled in this study. CPT-11 (60 mg/m2) in 500 m/5% glucose was given intravenously on Days 1, 8, and 15, before cisplatin (60 mg/m2) in 500 ml normal saline. The treatment was repeated every 4 weeks for 2 or 3 cycles. All patients were evaluable for response and toxicity. Two achieved a clinical complete response (CR), 11 had a partial response (PR), 2 had no change (NC) and 1 had progressive disease (PD), for an overall response of 81.3%. Neutropenia was observed in 100% (> grade 3: 70.6%) and diarrhea was recorded in 55.9% (> grade 3: 5.9%). The combination of CPT-11 and cisplatin in locally advanced cervical cancer is thus an active regimen with a manageable toxicity as a neoadjuvant chemotherapy.

Adult↗

PubMed2000

[Neuroimaging features of intraventricular neurocytoma].

We presented the clinicopathological features of 8 cases of intraventricular neurocytoma, which was a rare, benign tumor of neuronal origin and affected young patients. In each case the intraventricular tumor existed near the foramen of Monro and/or body of the lateral ventricle, and was associated with ventricular dilatation. A CT scan demonstrated a well-circumscribed iso- or hyperdense mass with some calcification, intratumoral cysts of various sizes and a heterogeneous enhancement. MRI, which was performed in 4 cases, confirmed a mass of isointense or slightly hyperintense on T 1-weighted images, and with multiple sites of attachment (mainly to the septum pellucidum and the head of the caudate nucleus). While these neuroimaging features are helpful in eliminating alternative diagnosis such as ependymomas, choroid plexus papillomas, subependymal giant cell astrocytomas and meningiomas, age of the patient and the tumor location within the lateral ventricle are important features for differential diagnosis.

Adult↗

PubMed2000

[Surgical treatment for temporal lobe epilepsy in childhood].

We retrospectively analyzed 5 children (11-15 year) with intractable temporal lobe epilepsy (TLE) who underwent the anterior temporal lobectomy with hippocampectomy. Cases 1-3 had medial TLE (MTLE) with histologically verified hippocampal sclerosis, Case 4 had lateral TLE, and Case 5 had MTLE with old hemorrhagic lesion in the lateral temporal lobe. In Cases 3-5, chronic invasive electrocorticography recording using subdural electrodes was obtained, while in Cases 1 and 2, the epileptogenic region was defined by noninvasive preoperative evaluation. Postoperatively, Cases 1-3 became seizure free. All patients had psychosocial problems after the onset of their epilepsy, which was not improved even after the surgical control of epilepsy. Since most patients had morphological change and perfusional and metabolic disturbance outside the hippocampus at the time of surgery, earlier surgical consideration may be necessary.

Adolescent↗

PubMed2000

[Medulloblastoma with neuronal differentiation: a report of five cases].

This report presents a retrospective analysis of 5 patients who were treated for cerebellar medulloblastoma with neuronal differentiation. Four males and 1 female ranged in age from 6 months to 9 years at the time of diagnosis. Total removal of the tumor was achieved in 3 patients, and partial removal in 2. While these tumors were composed of small cells and had regions resembling desmoplastic medulloblastoma, they in part showed neuronal characteristics which included parallel row or linear array arrangements of tumor cells in an eosinophilic fibrillary matrix. Postoperatively, 3 patients received craniospinal radiation therapy, one received local radiation to the primary site, and the remaining one received only systemic chemotherapy. During the follow-up period of 3.8-25.2 years, 4 patients have been in continuous remission with mild to moderate neurological deficits, while the remaining one died 3.9 years after surgery. The clinical and anatomic pathological features of medulloblastomas with neuronal differentiation are reviewed while the therapeutic problems associated with these tumors are also discussed.

Cerebellar Neoplasms↗

PubMed2000

[Occipital encephalocele and epilepsy].

We report the incidence of epilepsy in 7 patients with occipital encephalocele (meningocele: 6 cases, meningoencephalocystocele: 1 case). Two cases had epilepsy and a case without the history of epileptic seizure had an epileptic pattern on the EEG. All these 3 cases had cortical dysplasia(CD) such as schizencephaly and subcortical gray matter, and two of them were associated with mental retardation. The location of the prominent CD was correlated with the EEG abnormalities and clinical epileptic pattern in each case. Associated hydrocephalus and placement of VP shunt had no significant influence on the occurrence of the epilepsy. Thus, complicated CD is thought to be epileptogenic in patients with occipital encephalocele.

Adolescent↗

PubMed2000

Calcium phosphate crystal-associated proteins: alpha2-HS-glycoprotein, prothrombin F1, and osteopontin.

PURPOSE: To elucidate the process of urinary stone formation, many urinary constituents have been examined as inhibitors or promoters. MATERIALS AND METHODS: We analyzed specific binding proteins of calcium phosphate (CaP) crystals generated in human urine and found that the separated proteins were alpha2-HS-glycoprotein, prothrombin fragment 1 (PTF1), and osteopontin (OPN). We also studied their inhibitory effects on calcium oxalate crystallization and the quantitative differences in urinary excretion of the proteins in healthy individuals and stone formers. RESULTS: Both PTF1 and OPN had strong inhibitory effects on growth of calcium oxalate crystals. No differences in alpha2-HS-glycoprotein were found between healthy subjects and stone formers. Urinary concentrations of PTF1 and OPN were lower in stone formers than in healthy controls. No differences in these proteins were seen between single and recurrent stone formers. CONCLUSION: Low urinary concentrations of PTF1 and OPN might be one reason for stone formation.

Adolescent↗

PubMed1999

Solitary fibrous tumor in neurosurgical practice.

Solitary fibrous tumors most often affect the pleura, but examples are increasingly being reported in a wide variety of sites including the central nervous system. This tumor shows characteristic expression of CD34, which facilitates histopathologic differentiation of this lesion from other more common and better recognized spindle-cell tumors such as fibrous meningioma, hemangiopericytoma, or nerve sheath tumors. In this paper, we review current information on cranial and paracranial solitary fibrous tumors and emphasize the need for clinical recognition of this lesion as a distinct entity.

Journal Article↗

PubMed1999

Percutaneous papillary balloon dilatation as a therapeutic option for cholecystocholedocholithiasis in the era of laparoscopic cholecystectomy.

The present study was conducted to evaluate the effectiveness of percutaneous papillary balloon dilatation (PPBD) as a therapeutic option for cholecystocholedocholithiasis, in combination with laparoscopic cholecystectomy (LC). A total of 15 patients with both bile duct and gallbladder stones were clinically investigated. In 14 patients, PPBD was performed 2 to 7 days prior to LC, while in the remaining patient, PPBD was performed immediately after LC under general anesthesia in one continuous session. The bile duct stones were successfully pushed out into the duodenum in all the patients, seven of whom required two sessions for complete stone clearance, while the other eight needed only one session. Two patients had bile duct stones larger than 12 mm in diameter, necessitating electrohydraulic lithotripsy under cholangioscopy. The insertion of a percutaneous transhepatic biliary drainage tube did not cause intra-abdominal adhesions severe enough to contraindicate the use of LC. The operation times for LC varied from 80 to 184 min, with a mean operation time of 132 min, and the average postoperative and overall hospital stays were 9 and 26 days, respectively. There were no deaths or major complications, apart from transient hyperamylasemia. The findings of this study indicate that PPBD combined with LC is a safe and effective therapeutic option for cholecystocholedocholithiasis.

Aged↗

PubMed1999

Urinary disturbance after therapy for cervical cancer: urodynamic evaluation and beta2-agonist medication.

Urinary disturbance frequently develops following therapy for cervical cancer; however, no effective medical treatment has so far been reported. Sixty-five patients who developed urinary disturbance after radiation therapy, radical hysterectomy or radical hysterectomy with radiation therapy for cervical cancer underwent urodynamic assessment. Those who underwent radical hysterectomy with radiation therapy experienced the most severe urine loss, as determined by the pad test. All patients showed markedly reduced bladder compliance. A beta2-agonist (mabuterol) significantly improved compliance, bladder capacity and flow rate. It is suggested that medication with mabuterol is a potential novel approach to the treatment of urinary disturbance after therapy for cervical cancer.

Adrenergic beta-Agonists↗

PubMed1999

Melanotic neuroectodermal tumour of infancy at the anterior fontanelle.

We describe a 4-month-old girl presenting with a melanotic neuroectodermal tumour of infancy at the anterior fontanelle. According to the neuroimaging findings, this tumour was found to lie epidurally, adherent to the dura mater, with thickening of the adjacent frontal bone. The tumour was dense on CT, while MRI showed a major part of the tumour to be isointense with cerebral cortex on both T1- and T2-weighted images. The neuroimaging and clinical features are briefly discussed.

Cerebral Cortex↗

PubMed1999

Nonbacterial prostatitis caused by partial urethral obstruction in the rat.

The pathogenesis of nonbacterial prostatitis (NBP) is not understood mainly due to the lack of appropriate experimental models. We developed a new experimental model of NBP by inducing a partial obstruction of the urethra (PUO) in the rat. Male Wistar rats aged 12 weeks were used. PUO was produced by a nylon ligature on the urethra over a rubber tube. The tube was slipped out after the ligature had been tied. Two rats were examined histologically 6 h, 1 day, 3 days and 7 days after PUO. In another group, two rats were killed at 1, 3 and 7 days after the release of the PUO that had been left in place for 3 days. On day 3, another eight rats with PUO and eight control rats had 2 ml of urine in the bladder replaced by the same volume of lucifer yellow (LY; 10 microg/ml, MW 500), microperoxidase (MP; 20 microg/ml, MW 1900), horseradish peroxidase (HRP; 10 microg/ml, MW 40 000), or saline as control, respectively. Lymphocytic infiltration and interstitial edema were noted in the prostate following PUO, being most prominent on day 3. After the release of the PUO, these inflammatory changes gradually disappeared. Only LY was noted within the prostatic stroma of the rats 2 h after bladder instillation. Intraprostatic urinary reflux may be an etiologic factor in NBP. The present study showed that lower urinary tract obstruction caused NBP in the rat. Penetration of prostatic tissue by low-molecular-weight substances in the urine may trigger NBP.

Administration, Intravesical↗

PubMed1999

Functional imaging in periventricular nodular heterotopia with the use of FDG-PET and HMPAO-SPECT.

We analyzed the interictal [18F]fluoro-2-deoxy-D-glucose positron emission tomography (FGD-PET) and single photon emission computed tomography with technetium-99m-hexamethyl-propyleneamine oxime (HMPAO-SPECT) in two epileptic patients with periventricular nodular heterotopia (PNH). In both cases, we found both the glucose metabolism and the perfusion of PNH to be almost identical to those of the normal cerebral cortex. The metabolic activity and perfusion in the heterotopic gray matter in a subependymal white matter area probably represent the glucose metabolism and perfusion of the abnormally located gray matter rather than a subclinical ictal phenomenon. FDG-PET and HMPAO-SPECT were thus found to be a useful complement to magnetic resonance imaging in the evaluation of PNH.

Adult↗

PubMed1999

Fibroxanthoma arising from the cranial dura mater.

A primary xanthomatous tumor is very rare in the central nervous system (CNS). Here we report the case of a fibroxanthoma arising from the dura mater of the cerebrum that demonstrated no systemic disease or metabolic abnormalities. A 19-month-old, otherwise healthy boy was found to have an enlarged head. Magnetic resonance imaging demonstrated a left occipital dural mass lesion and an enlarged left cerebral hemisphere with ipsilateral ventricular enlargement. Subtotal removal of the tumor was performed through the left parieto-occipital craniotomy. The tumor was composed of a central fibrous portion, a peripheral xanthomatous area, and a boundary. The peripheral area of the tumor showed abundant uniform xanthomatous cells with a thin fibrous stroma and the mass was diagnosed as fibroxanthoma involving the dura. This may represent a distinct category of tumor, which is different from the previously reported cases of fibrous xanthoma and fibrous histiocytoma. Intracranial xanthomatous tumors may be heterogeneous in their origin and histological features. However, further studies are needed to elucidate their clinical features, biological behavior, and optimal treatment strategies.

Brain Neoplasms↗

PubMed1999

Functional imaging in schizencephaly using [18F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) and single photon emission computed tomography with technetium-99m-hexamethyl-propyleneamine oxime (HMPAO-SPECT).

We analyzed interictal [18F]fluoro-2-deoxy-D-glucose positron emission tomography (FGD-PET) and single photon emission computed tomography with technetium-99m-hexamethyl-propyleneamine oxime (HMPAO-SPECT) in a 23-year-old female with schizencephaly. She had epilepsy and mild left hemiparesis, but was otherwise developmentally normal. We found the glucose metabolism and perfusion of the wall of the schizencephalic cleft to be identical to those of normal cerebral cortex. The wall of the transcerebral clefts, which were observed to be lined by abnormally organized gray matter as a result of a migration disorder, demonstrated gray matter metabolic activity and perfusion. FDG-PET and HMPAO-SPECT were thus found to be a useful complement to magnetic resonance imaging for evaluating schizencephaly.

Adult↗

PubMed1999

Subcellular distribution of tetrodotoxin in puffer fish liver.

The liver homogenate of puffer fish was fractionated into blood cell, nuclear, mitochondrial, microsomal and cytosol fractions by the differential centrifugation method. All the five fractions were toxic to mice, although the toxin amount was significantly high in the cytosol fraction. Analyses by HPLC and LC-FABMS demonstrated that tetrodotoxin is the major toxic principle in each fraction. These results reveal that tetrodotoxin is widely distributed in organelles in liver cells, though predominantly in the cytosol fraction.

Adult↗

PubMed1999

Intrinsic epileptogenicity of focal cortical dysplasia as revealed by magnetoencephalography and electrocorticography.

Focal cortical dysplasia (FCD) is often associated with severe partial epilepsy. In this study, we performed magnetoencephalography (MEG) and electrocorticogrsphy (ECoG) on four patients with FCD-associated epilepsy to confirm the 'intrinsic' epileptogenicity of FCD. In all patients, we determined the three-dimensional locations of the magnetic sources of the interictal paroxysmal activities by a single dipole model, and then the estimated dipole localization was superimposed on the magnetic resonance image. The dipole clusters were located in the T2-prolonged lesions, namely in the FCD lesions themselves. All patients underwent surgery for their medically intractable epilepsy, and the acute and/or chronic ECoG were thereafter recorded. Either frequent or continuous paroxysmal activities were recorded from the ECoG electrodes which were placed over the surface of the FCD lesion, while few paroxysmal activities were observed on the normal appearing adjacent cortex. Intraoperative depth recordings were performed in a patient with the needle electrode inserted into the FCD lesion and they revealed these paroxysmal foci to be located not on the cortical surface but at a depth of 15 mm from the cortical surface where both abnormal giant neurons and bizarre large eosinophilic cells (so-called balloon cells) were also prominently observed on the postoperative histological sections. Following a lesionectomy combined with the removal of the underlying white matter, three patients demonstrated a favorable seizure outcome. Our findings thus suggest the FCD lesions to be highly and intrinsically epileptogenic lesions.

Adult↗