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Biomedical subjects

Y Iwai

Publications and source records attributed to Y Iwai.

At least 55 records · Page 3Linked to original sources
PubMed1999

Successful treatment of brainstem abscess with stereotactic aspiration.

BACKGROUND: Brainstem abscess is an uncommon condition associated with a high mortality. We report a case of brainstem abscess in a 51-year-old female with a pulmonary arteriovenous fistula that was cured after appropriate antibiotic therapy following stereotactic aspiration. The value of stereotactic aspiration in the management of brainstem abscess is documented with a review of the relevant literature. CASE REPORT: A 51-year-old female with a pulmonary arteriovenous fistula suffered fever, diplopia and weakness on the right side. Magnetic resonance (MR) imaging of the brain showed a large cystic mass with ring-like enhancement in the brainstem. A diagnosis of brainstem abscess as a complication of pulmonary arteriovenous fistula was made. MR imaging-guided stereotactic exploration was carried out via the suboccipital transcerebellar approach and the pathogen of the brainstem abscess was identified. The brainstem abscess was cured after treatment employing antibiotics to which the pathogen was sensitive. CONCLUSIONS: Stereotactic aspiration is an effective procedure for brainstem abscesses. This procedure is less invasive than open surgery and can be performed even in patients in poor general condition.

Arteriovenous Fistula↗
PubMed1999

Taxonomic study and morphological differentiation of an actinomycete genus, Kitasatospora.

The history and taxonomic criteria of the actinomycete genus, Kitasatospora, are described. The reasons for a change of the position of the genus in the classification system are given and a restriction length polymorphism (RFLP) method for rapid identification is described. Although the bacterial genus, Kitasatospora, resembles the fungal one, Streptomyces, in its morphology, it is clearly different in its cell-wall composition which includes LL- and meso-DAP, glycine and galactose. Following a change in its taxonomic position as a result of insufficient gene analysis, it was re-established by phylogenetic analysis of the entire 16S rRNA gene. Most actinomycetes produce bioactive compounds but the relationship between antibiotic production and morphology has not been studied in detail. Kitasatospora strains may be used as a model because they grow in submerged culture like those actinomycetes strains which produce bioactive compounds. The authors suggest further studies of the correlation between metabolic and morphological differentiation and the mechanism of the production of submerged spores.

Actinomycetales↗
PubMed1999

Volatile components in stored rice [Oryza sativa (L.)] of varieties with and without lipoxygenase-3 in seeds.

Lipoxygenase (LOX) is thought to play an important role in the formation of desirable or undesirable flavor and aroma in many plant products. In rice seeds, LOX activity is localized in the bran fraction and LOX-3 is the major isozyme component. We used gas chromatography-mass spectrometry to determine whether the degree of staleness in the flavor of stored brown rice was related to the presence of LOX-3. We found that the amount of hexanal, pentanal, and pentanol in normal raw LOX-3 rice markedly increased during storage at 35 degrees C. That in LOX-3-less rice increased slightly but was a third to a fifth that of normal LOX-3 rice. In cooked rice, the amount of these components from glutinous rice exceeded that in nonglutinous rice, and that in normal LOX-3 rice exceeded that in LOX-3-less rice. These results indicate that the stale flavor production in LOX-3-less rice during storage is less than that in normal LOX-3 rice.

Aldehydes↗
PubMed1999

Venous angiomas with arteriovenous shunts: report of three cases and review of the literature

OBJECTIVE AND IMPORTANCE: In spite of recent recognition of the benign nature of venous angioma (VA), only limited information is available on the clinical features of VA with arteriovenous shunt (AVS). The purpose of this study was to elucidate the clinical profile of VA with AVS. CLINICAL PRESENTATION AND INTERVENTION: We describe three patients having a VA with AVS and review the clinical features of 31 patients reported in the literature, including our three patients. The patients included 12 women and 19 men, ranging in age from 18 to 54 years. Seven patients (22.6%) presented with intracranial hemorrhage, and none of 16 patients developed a new or recurrent hemorrhage (mean follow-up period, 11 months). Treatment was conservative in 14 patients, lobectomy or partial resection of the VA in 6, removal of hematoma in 4, operation only for coexisting aneurysm or arteriovenous malformation in 4, and not known in 3. The outcome was reported as good recovery in 19 patients, persistent neurological deficits in 2, death or deterioration not related to the VA in 3, and not known in 7. CONCLUSION: Although there remains some uncertainty as to the clinical features of VA with AVS, its prognosis seems to be essentially as benign as that of VA without AVS. Thus, conservative treatment is recommend except for patients with a large hematoma or with a coexisting arteriovenous malformation or a symptomatic, accessible cavernous angioma, which may be treated by surgical intervention. Further collection of data is required to establish definite treatment guidelines.

Journal Article↗
PubMed1999

Gamma Knife radiosurgery for metastatic brain tumor: the usefulness of repeated Gamma Knife radiosurgery for recurrent cases.

Forty-one patients with a total of 193 metastatic brain tumors were treated because of new lesions or in a few cases because of tumor regrowth. The management involved two to four treatments with Gamma Knife radiosurgery (GKRS). The overall median survival was 15 months. The local control rate of tumors was 89% for the first treatment and 93% for repeated treatments. Symptomatic radiation-induced edema appeared in only two cases (4.9%). Patients with metastatic brain tumors who developed new lesions after GKRS were treated with GKRS alone for subsequent lesions. It was possible to control tumors for a long period with minimal side effects. As a result, we were able to maintain the quality of life of these patients, but, the effect of GKRS in controlling tumor regrowth seemed temporary.

Actuarial Analysis↗
PubMed1999

Gamma Knife radiosurgery for skull base metastasis and invasion.

We treated 18 patients with skull base metastasis or invasion using Gamma Knife radiosurgery. Seven of these patients had invasive nasopharyngeal cancer and 11 had distant metastasis from other cancers. The mean diameter of tumors was 22-46 mm (median 32.1 mm) and the radiation dose to the tumor margin was 12-23 Gy (median 16.2 Gy). The median follow-up period was 10.5 months. Clinical symptoms were improved in 61% of the patients after treatment and tumor control was obtained in 67% of cases at their final followup. Radiation injury occurred in only one patient (6%) who had received previous radiotherapy to the same region. Gamma Knife radiosurgery is a useful therapeutic option for the treatment of skull base metastasis and invasion, either as a secondary treatment for recurrence after previous radiotherapy or as a primary treatment.

Actuarial Analysis↗
PubMed1999

Stereotactic radiosurgery for cavernous sinus cavernous hemangioma--case report.

A 40-year-old female presented with cavernous sinus cavernous hemangioma manifesting as left abducens and trigeminal nerve pareses. Magnetic resonance imaging revealed a left cavernous sinus tumor. The tumor was partially removed. Histological examination of the specimen confirmed cavernous hemangioma. Radiosurgery was performed using the gamma knife. The tumor markedly decreased in size after radiosurgery and morbidity was avoided. Cavernous sinus cavernous hemangiomas may be difficult to treat surgically due to intraoperative bleeding and cranial nerve injury. Stereotactic radiosurgery can be used either as an adjunct treatment to craniotomy, or as the primary treatment for small cavernous sinus cavernous hemangioma.

Abducens Nerve↗
PubMed1999

Cavernous angioma of the optic chiasm--case report.

A 31-year-old female presented with cavernous angioma originating from the optic chiasm manifesting as sudden onset of right retroorbital pain and right visual disturbance. She had a psychomotor seizure 10 years ago. Cavernous angioma at the right basal ganglia had been partially removed at that time. After the operation, the patient had left hemiparesis, but gradually improved. Neurological examination revealed decreased right visual acuity, left homonymous hemianopsia, and left hemiparesis. Magnetic resonance imaging revealed a mixed signal intensity mass at the right optic nerve to the optic chiasm with a low signal intensity rim on T2-weighted imaging, situated at the right basal ganglia where the cavernous angioma had been partially resected. Right frontotemporal craniotomy was performed by the pterional approach. A subpial hematoma was situated at the right optic nerve to the optic chiasm. The hematoma with an angiomatous component was completely resected from the surrounding structure. Histological examination of the specimens confirmed cavernous angioma. Postoperatively, her right visual acuity was slightly improved, but the visual field defect was unchanged. We emphasize the importance of correct diagnosis by magnetic resonance imaging and subsequent resection for preserving and improving the visual function of patients with cavernous angiomas of the optic chiasm.

Adult↗
PubMed1999

Dual origin of the vertebral artery--case report.

A 27-year-old female presented with dual origin of the left vertebral artery. Twenty-six cases of this rare congenital vascular anomaly have been reported. In general, the medial leg of the dual origin of the vertebral artery enters a higher transverse foramen (usually the fifth or less frequently the fourth) than the lateral leg, which usually enters the sixth. Exceptions to this rule occur when the medial and lateral legs of the right vertebral artery enter the right seventh and sixth transverse foramina, respectively. This congenital vascular anomaly has diagnostic and therapeutic implications in any intervention involving the proximal vertebral artery.

Adult↗
PubMed1999

[Two cases of bladder tumor producing granulocyte colony stimulating factor].

Two cases of bladder tumor producing granulocyte colony-stimulating factor (G-CSF) are reported. The first case was in a 79-year-old female patient. A large bladder tumor was diagnosed as right-sided hydronephrosis. The tumor consisted mostly of squamous cell carcinoma with a few transitional cells. Total cystectomy could not be performed because of direct invasion by the tumor into the pelvis. The patient died without aggressive treatment about 7 months after admission. Her leukocyte count consistently increased up to 76,200/mm3. The serum G-CSF levels were not analyzed. However, immunohistochemical examination revealed a high concentration of G-CSF in the tumor specimen. The other case was in an 80-year-old male patient. The patient, who had refused total cystectomy for bladder tumor (transitional cell carcinoma, grade 2, T2N0M0) 2 years earlier, underwent ureterocutaneostomy for obstructive renal insufficiency. Total cystectomy was not performed at this admission because of tumor invasion into the rectum and his advanced age. Radiotherapy was administered. However, he developed ileus caused by direct tumor invasion into the ileum. He died about 10 months after the urinary diversion. Leukocytosis, which improved transiently following radiotherapy, became more severe. The maximum leukocyte count was 49,500/mm3 just before death. The serum G-CSF levels during and after radiotherapy were 54 pg/ml and < 30 pg/ml, respectively. Immunohistochemical examination revealed the presence of G-CSF in the tumor. These findings suggest the production of G-CSF by the bladder tumor.

Aged↗
PubMed1998

Differential expression of SHP2, a protein-tyrosine phosphatase with SRC homology-2 domains, in various types of renal tumour.

SHP2, a widely distributed protein-tyrosine phosphatase with src homology-2 (SH2) domains, is highly expressed in the brain and may play a role in synaptic communications or cellular proliferation. In this study, we examined SHP2 protein expression in 110 renal cell tumours of various histological subtypes, including clear, granular, papillary, chromophobe, collecting duct, and sarcomatoid-type renal cell carcinoma (RCC), and oncocytoma. SHP2 was expressed predominantly in normal distal tubules and collecting ducts, and positivity in various types of renal tumours was as follows: clear cell RCC, 0% (0/77 cases); granular, 7.7% (1/13); papillary, 50% (3/6); sarcomatoid, 0% (0/1); chromophobe, 85.7% (6/7); collecting duct carcinoma, 0% (0/2); oncocytoma, 100% (4/4). Clear and granular-type RCCs showed a very low but positive expression of SHP2. Chromophobe RCC and oncocytoma showed the highest rates and strongest intensities of SHP2 protein on immunostaining. SHP2 may serve as a powerful marker in detecting rare tumours. Estimates of its expression may be useful in histological diagnosis.

Adenoma, Oxyphilic↗
PubMed1998

Intracranial aneurysms in identical twins.

BACKGROUND: Though familial intracranial aneurysms are well documented, only a few cases of intracranial aneurysms in identical twins have been reported. CASE REPORT: Our patient, a 46-year-old woman, presented with a subarachnoid hemorrhage (SAH) due to a ruptured aneurysm. At the age of 36, her identical twin sister had also suffered SAH from a ruptured aneurysm. Both twins were treated successfully. CONCLUSION: The likelihood of the occurrence of an aneurysm may be higher for a twin whose identical twin has developed an aneurysm than for the general population. Therefore, it is reasonable to perform certain screening procedures for aneurysms on an asymptomatic twin when the other presents with SAH due to a ruptured aneurysm.

Diseases in Twins↗
PubMed1998

Development of a health promotion system for the elderly: Committee of Health Evaluation for Elderly Persons Council of Japan AMHTS Institutions.

A new health promotion approach for elderly persons is required which maintains not only their physical health but also their quality of life. We are developing a health promotion system which makes use of questionnaires dealing with physical conditions and quality of life, and makes health reports. Health evaluation is carried out in three steps. First, detailed information about the physical health of each client is collected. Second, quality of life is evaluated according to five health indicators. Last, health recommendations are generated. An artificial intelligence (AI) program produces detailed questions to collect necessary information for the evaluation of a client's health. The information related to quality of life is converted into five health indicators and presented as a radar-chart in documents and displays. The knowledge-based AI program automatically generates the health recommendation documents. This information is available for physicians and nurses for health counseling.

Aged↗
PubMed1998

Succinylated collagen crosslinked by thermal treatment for coating vascular prostheses.

Vascular prostheses coated with collagen carefully prepared to avoid contamination were tested to see if it could induce endothelial cell lining throughout the graft surface in a natural way. The collagen fibers were succinylated. Hydrogel produced with the succinylated collagen was used for the sealant to reduce the amount of solid substance. To avoid contamination and the side effects of chemical reagents, the collagen thermally crosslinked under sterile conditions. A suspension of the collagen fibers was enmeshed in the interstices of Dacron fibers of fabric prostheses, which were then thermally crosslinked at 130 degrees C for 20 h. The prostheses were porous when the collagen fiber network was dry. Under wet conditions, however, the water permeability of the grafts was reduced to 0.1 ml/min from the 1,250 ml/min of the original prostheses. Three weeks after implantation in the abdominal aortas of dogs, 81.2 +/- 11% of the luminal surface was macroscopically thrombus free, and 56 +/- 14% was endothelialized. More than 95% of the coated collagen had been absorbed. Numerous fibroblasts had migrated into the graft walls, and capillary blood vessels had infiltrated the inside of the graft walls without foreign body reaction. In the controls, thrombus free areas averaged 9.0 +/- 5%, and endothelialized areas averaged 5.2 +/- 4%. Many giant cells, plasma cells, and lymphocytes had migrated into the graft walls, but no fibroblasts. These results suggest that rapid endothelialization is possible when clean collagen is used.

Animals↗
PubMed1998

Bilateral dissecting aneurysms of the vertebral arteries resulting in subarachnoid hemorrhage: case report.

OBJECTIVE AND IMPORTANCE: We present the case of a patient with bilateral dissecting aneurysms of the vertebral arteries resulting in subarachnoid hemorrhage. CLINICAL PRESENTATION: A 44-year-old man suffered a sudden onset of severe occipital headache and nausea and then dysphasia caused by subarachnoid hemorrhage. A computed tomographic scan demonstrated right side dominant subarachnoid hemorrhage mainly in the posterior fossa. Angiography revealed bilateral, vertebral dissecting aneurysms. The right aneurysm was larger and had a bleb-like protrusion, which strongly suggested a causative lesion of the subarachnoid hemorrhage. Six months later, the patient was referred to our hospital for further evaluation and treatment. INTERVENTION: The ruptured right aneurysm was trapped surgically through a lateral suboccipital approach. The patient's postoperative course was unremarkable, and he was discharged on the 14th day after surgery. However, postoperative angiography demonstrated slight enlargement of the left nonruptured aneurysm. Four months after surgery, the patient developed brain stem ischemic symptoms. The angiography conducted at that time showed further enlargement of the left aneurysm. Five months after surgery, fatal rupture of the left aneurysm occurred. CONCLUSION: These results indicate that sacrifice of the unilateral vertebral artery may result in an enlargement of the contralateral nonruptured aneurysm and may thus be dangerous in the case of a patient with bilateral dissecting aneurysms.

Adult↗
PubMed1998

Sheath proteins: synthesis, secretion, degradation and fate in forming enamel.

We investigated expression of ameloblastin and sheathlin, recently cloned enamel matrix proteins from the rat and pig, in forming enamel immunocytochemically and immunochemically, using region-specific antibodies. The results obtained from the rat and pig were essentially the same. Antibodies which recognize the N-terminal region stained the secretory machinery of the secretory ameloblast and the entire thickness of the enamel matrix, especially the peripheral region of the enamel rod. Immunostained protein bands were observed near 65 or 70 kDa and below 20 kDa. C-terminal-specific antibodies stained the secretory machinery of the ameloblast and the immature enamel adjacent to the secretion sites. Immunostained protein bands were found ranging from 25 to 70 kDa. Antibodies which recognize a region in the protein just prior to the C-terminal region stained the cis-side of the Golgi apparatus but not the enamel matrix. Immunostained protein bands were observed of about 55 kDa. These results suggest that post-translational and post-secretory modifications of ameloblastin and sheathlin are similar to each other, and further showed that their cleaved N-terminal polypeptides concentrate in the prism sheath. We propose that sheathlin and ameloblastin share the same role in amelogenesis and should be classified as sheath proteins.

Animals↗
PubMed1998

Multiple remote brain hemorrhages after removal of a giant colloid cyst of the third ventricle--case report.

A 59-year-old male presented with progressive gait and memory disturbance. Computed tomography (CT) showed a huge high density mass, of about 45 mm maximum diameter, in the third ventricle with marked hydrocephalus. Magnetic resonance imaging showed the mass as mixed iso- to hypointensity on T2-weighted imaging and high intensity on T1-weighted imaging. Bifrontal craniotomy was carried out. The histological diagnosis was colloid cyst. Six hours after the operation, a large quantity of cerebrospinal fluid (CSF) was discharged via an epidural drainage, accompanied by generalized convulsion. CT showed multiple brain hemorrhages and subarachnoid hemorrhage remote from the operative field. The cause of hemorrhages is obscure, but postoperative overdrainage of CSF through epidural drainage over a short time following excessive intraoperative CSF aspiration may have contributed to this rare complication.

Brain Diseases↗