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Biomedical subjects

N Kuwana

Publications and source records attributed to N Kuwana.

At least 19 recordsLinked to original sources
PubMed1995

Dopamine responsiveness of human prolactinoma cells as determined by the reverse hemolytic plaque assay.

The responsiveness in vivo to dopamine of prolactin (PRL) secretion in patients with prolactinoma was compared with that in vitro of single cells obtained from the same prolactinomas by surgical operations. Six patients with prolactinoma showing various degrees of hyperprolactinemia were challenged by bromocriptine suppression test (2.5 mg, peroral) before operation. Bromocriptine administration caused a decrease in the serum PRL concentration ranging 24-95% and there was no correlation between the basal PRL level and bromocriptine-induced inhibition. Monodispersed pituitary cells obtained from the prolactinomas by operation were subjected to a reverse hemolytic plaque assay for PRL to determine PRL secretion at the single cell level under basal conditions as well as in response to dopamine. The percentage of plaque-forming cells under basal conditions ranged 15-55% among the prolactinomas. The percentage of plaque-forming cells and plaque area were decreased in a dose-dependent manner by 10(-7) - 10(-5) M dopamine for the pituitary cells obtained from some adenomas but not for those from other adenomas. When the inhibition rates in vitro due to 10(-5) M dopamine in these two parameters were compared with the inhibition rate in vivo in the serum PRL concentration due to bromocriptine, it was found that there was a significant correlation between them. These results show that the reverse hemolytic plaque assay can be used to determine in vitro responsiveness to dopamine of PRL secretion from single prolactinoma cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Differentiation of malignant glioma and metastatic brain tumor by thallium-201 single photon emission computed tomography.

The use of superdelayed thallium-201 single photon emission computed tomography (201Tl SPECT) for differentiating malignant gliomas from cerebral metastases was investigated in 23 patients (7 with meningioma, 6 with glioma, 7 with cerebral metastasis, 1 with each of neurinoma, abscess, and necrosis). 4 mCi of 201Tl was injected intravenously, and gamma camera scans were performed after 10 minutes and 4, 24, 72, and 96 hours (superdelayed scan). The mean thallium index of meningiomas was significantly higher than those of gliomas and cerebral metastases after 10 minutes, while the mean thallium indices of meningiomas and gliomas were significantly higher than those of cerebral metastases after 96 hours. The combination of early and superdelayed 201Tl SPECT may be useful in differentiating malignant gliomas from cerebral metastases.

Aged↗
PubMed1993

Progressive diffuse arteriovenous malformation--case report.

A rare diffuse arteriovenous malformation (AVM) occurred in an 11-year-old boy with a 4-year history of transient ischemic attacks and weakness of the left extremities. Postcontrast computed tomography (CT) showed cord-like enhancement in the corpus callosum and pineal region. Magnetic resonance (MR) imaging demonstrated atrophy of the right hemisphere and multiple signal voids in the sulci. Cerebral angiography showed a diffuse AVM fed by the bilateral anterior cerebral and right middle cerebral arteries. The AVM nidus consisted of scattered nidi. Several draining veins appeared as multiple signal voids on MR images. No surgery was possible because of the scattered nidi. Left hemiparesis and mental retardation worsened, with progressive atrophy of the right hemisphere on serial MR images. Follow-up radiological examinations showed that the number of nidi increased, the draining vein enlarged, and the gyri calcified. The gyriform calcification on CT scans strongly resembled that seen in Sturge-Weber syndrome.

Cerebral Angiography↗
PubMed1992

[Cephalic index in the case of chronic subdural hematomas; a preliminary report].

As a low cephalic index (cephalic index = breadth x 100/length), also called "dolichocephaly" has often been observed in patients with chronic subdural hematomas, the relation between the occurrence of chronic subdural hematoma and the cephalic index was investigated. 62 patients (male: 51, female: 11) with chronic subdural hematomas who were admitted during the past 5 years, and 62 patients (male: 51, female: 11) aged 40 years and over who visited the hospital for head injury which caused no intracranial hematoma, randomly sampled, as a control group, a total of 124 patients were studied for cephalic index on plain craniogram. The average cephalic index was 79.0 for males and 81.3 for females in the chronic subdural hematoma group, compared with 82.1 for males and 83.3 for females in the control group. The former index was lower than the latter for both sexes. Dolichocephaly was observed in 8 out of 51 males (15.7%) with chronic subdural hematomas while it was observed in only 1 out of 51 males (2.0%) in the control group. Since it has been reported that dolichocephaly depends on the development of arcus superciliaris and protuberantia occipitalis externa by the interaction between androgen and GH in males as well as time of closure of the cranial suture in childhood, and as androgen accelerates offensive behavior and GH stimulates the synthesis of collagen, the occurrence of chronic subdural hematoma is potentially related with sexual or individual variation in such endocrinic environments.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Chronic subdural hematoma with a markedly fibrous hypertrophic membrane. Case report].

A 40-year-old female, who had taken low-dose oral contraceptives for 2 months before onset, developed transient dysarthria, left hemiparesis, and left hemihypesthesia. One month later, a computed tomography (CT) scan revealed a uniformly enhanced, convex-shaped, hypertrophic membrane with a lobulated lumen in the subdural space of the right parietal region. A right parietal craniotomy was performed. The membrane, consisting of elastic-hard, hypertrophic granulation tissue and yellowish, sticky fluid in the lumen, was readily freed and totally extirpated. Subsequently, the patient recovered without persistent symptoms. Light microscopic examination detected the sinusoidal channel layer and the fibrous layer in an alternating configuration, along with intramembranous hemorrhagic foci. Such hypertrophy must have been caused by repeated intramembranous hemorrhages and reactive granulation. Such findings of hematoma membrane have never previously been reported. Thus, this is an interesting case, clearly distinguished from typical chronic subdural hematoma.

Adult↗
PubMed1990

Massive hemorrhage in acoustic neurinoma after minor head trauma--case report.

Massive hemorrhage within an intracranial neurinoma occurs rarely. The authors describe a 62-year-old female with intratumoral bleeding which led to the discovery of an acoustic neurinoma. She developed a gait disturbance after a minor head injury. A computed tomographic scan obtained 2 months later demonstrated multiple high-density areas in the anterior portion of the left cerebellopontine angle. Preoperative diagnosis was acoustic neurinoma. The tumor had multiple cysts which contained a mixture of xanthochromic fluid and old, brownish hematomas, and was successfully removed. The intratumoral hemorrhage is thought to have resulted from traumatic rupture of the dilated vessels, although the trauma was slight. This is the first reported case of an acoustic neurinoma discovered through treatment for intratumoral hemorrhage occurring after a minor head injury.

Brain Injuries↗
PubMed1989

Klippel-Trenaunay-Weber syndrome with spinal arteriovenous malformation--case report.

A 28-year-old female with Klippel-Trenaunay-Weber syndrome associated with an arteriovenous malformation (AVM) of the spinal cord is reported. She was admitted to our hospital with a 4-month history of steadily progressive weakness and dysesthesia of the legs. A nevus flammeus, varices, hypertrophy and elongation of the left leg had been present since her infancy. These symptoms progressed and she became unable to walk and pass water by herself. Myelography disclosed a spinal AVM extending from Th11 to L2. Angiography confirmed the presence of stretched and tortuous vessels as well as an arteriovenous shunt in the left leg. Magnetic resonance imaging showed a high-intensity area extending from Th10 to L2. Following laminectomy from Th10 to L2 and resection of the AVM, her motor and bladder functions worsened. However, 6 months later, her motor function improved to the preoperative state and the bladder dysfunction disappeared. The coexistence of Klippel-Trenaunay-Weber syndrome with spinal AVM, considered to be rare, is discussed, and the pertinent literature is reviewed. The case presented here is the first to have been surgically treated in Japan.

Adult↗
PubMed1989

Parapontine trigeminal cryptic angiomas presenting as trigeminal neuralgia.

Posterior fossa microvascular decompression surgery was attempted in 1257 patients with trigeminal neuralgia (TN), of whom seven had a very unusual cryptic angioma. The lesions were not visualized on preoperative enhanced computerized tomography scans, and serial angiography demonstrated a small vascular stain in only one case. The character of the facial pain was indistinguishable from TN caused by vascular compression and there was no other specific symptomatology. The patients' age and sex distributions were also compatible with classical TN. Cryptic angiomas presenting as typical TN without other symptoms have not been reported before, but they should be kept in mind in the differential diagnosis and surgical management of TN.

Cerebral Angiography↗
PubMed1988

A new technique for percutaneous study of lumboperitoneal shunt patency. Technical note.

A new technique for percutaneous imaging of a one-piece lumboperitoneal shunt is described. Patency of the shunt can be assessed by the intraperitoneal spread of contrast medium which is injected intrathecally via the lumbar route. No special equipment or instrumentation is required other than a typical lumbar puncture tray and a general examination tilt table for fluoroscopy.

Cerebrospinal Fluid Shunts↗
PubMed1982

Morphological investigations on cerebellar "neuroblastoma" group.

Classic medulloblastoma is a relatively common and distinct clinicopathologic entity consisting of primitive multipotential cells with differentiating capacity to neuroblastic and/or glial cell lines. Desmoplastic medulloblastoma has some features in common with cerebellar neuroblastoma, in which ultrastructural evidence of significant neuroblastic differentiation is extremely rare. We studied three cerebellar tumors with evidence of neuronal differentiation as compared to four classical desmoplastic medulloblastomas. Two of three tumors contained the regions of different degrees resembling desmoplastic medulloblastoma and one consisted of neuroblastic cells exclusively. This spectrum of differentiation suggests a relationship between cerebellar neuroblastoma and medulloblastoma, especially of the desmoplastic type. The nature of cerebellar neuroblastoma and its nosology are briefly discussed.

Adult↗
PubMed1979

Lymphoma of the brain associated with polyposis of the colon--report of a case and review of Turcot's syndrome.

Pathological findings of a 15-year-old girl with polyposis of the colon who has subsequently developed primary lymphoma of the brain are reported. The authors consider this case to be a rare example of Turcot's syndrome although the histological typing of the brain tumor is not classical and familial background of the polyposis has not been demonstrated. Literatures on 14 previously reported cases of Turcot's syndrome are reviewed and clinical and pathological findings are summarized. The present case is the second report of Turcot's syndrome associated with lymphoma of the brain and is unique in regard to the age as cerebral lymphoma is extremely rare in the second decade.

Adolescent↗