Biomedical subjects

K Yada

Publications and source records attributed to K Yada.

At least 37 records · Page 2Linked to original sources

PubMed1995

[Epidemiology of syringomyelia in Japan--the nationwide survey].

The nationwide epidemiological survey of syringomyelia was carried out in Japan by sending inquiries to neurologists, child neurologists, neurosurgeons and orthopedic surgeons for the period of 1991 and 1992. A total of 1,243 cases of syringomyelia were ascertained. Among them, 622 were men and 619 women, and the average age of onset was 28 years old. The classification by Barnett et al was used, presenting syringomyelia with Chiari malformation in 684 cases (51.2%), dysraphism in 47 (3.7%), post traumatic syringomyelia in 139 (11%), post-spinal arachnoiditis in 76 (6%), spinal cord tumor in 132 (10.5%) and others in 204. Its predominant clinical course was slowly progressive, but 202 cases (17.9%) showed rather stable course including spontaneous resolution in 29 cases. The main initial symptoms were numbness in 522 cases (42%), motor disturbance in 504 (40.5%), and pain in 296 (23.8%). Neurologic signs noted in the abnormality of deep tendon reflexes in 836 cases (67.3%), motor disturbance in 763 (60.4%) and positive pathological reflexes in 383 (30.1%). Sensory disturbance was found in 942 cases (75.8%) and the dissociated type were 559 out of them (59.3%). It is noteworthy that 982 out of 1,243 were documented by MRI and surgical operations such as foramen magnum decompression, syringo-subarachnoid shunt and others were performed in 829 cases. Syringobulbia was confirmed on MRI in 101 cases of syringomyelia in which spinal cord tumors were most frequently associated.

Adolescent↗

PubMed1994

Spinal cord intramedullary pressure. A possible factor in syrinx growth.

STUDY DESIGN: This study analyzed biomechanical characteristics of the cervical spinal cord, especially in relation to neck flexion. Intramedullary pressure was measured in different neck positions. OBJECTIVES: The results provided a rationale for dynamic changes in intramedullary pressure, with the flexed neck position playing a role in syrinx growth. SUMMARY OF BACKGROUND DATA: Dynamic changes in intramedullary pressure in the flexed position have been postulated to play an important role in syrinx growth. However, intramedullary pressure of the spinal cord has not been measured. METHODS: The authors designed a balloon method to assess, experimentally, intramedullary pressure dynamics of the spinal cord. A system was incorporated to examine the reliability of the balloons. Using 15 mongrel dogs, two balloons were embedded in the cervical spinal cord. Intramedullary pressure of the spinal cord was measured in several neck positions. In 5 of them, the same measurements were repeated when the spinal cord and roots were transected. RESULTS: When filled with a suitable volume of water, the balloons faithfully transmitted the pressure of the environment. No pressure differences were observed with the neck in the extended or neutral positions. However, when the neck was flexed, intramedullary pressure significantly increased. This increase in intramedullary pressure in the flexed neck position was not observed after spinal cord and roots were transected. CONCLUSION: The results indicated that the intramedullary pressure of the cervical spinal cord increases when the neck is flexed. This phenomenon might play an important role in syrinx growth.

Animals↗

PubMed1994

Anomaly of venous system in congenital occipital dermal sinus.

We report two cases of congenital occipital dermal sinus in which elongation of the vein of Galen, elevation of the straight sinus, division of the superior sagittal sinus, elevation of the confluence of sinuses, elevation of transverse sinus and narrowing of the torcular angle were observed in the venous phase of cerebral angiography. Enhanced computed tomography (CT) revealed enlargement of the supracerebellar cistern, elevation of the straight sinus and of the confluence of sinuses, but no evidence of intracranial lesions. In order to study the relationship between anomalies in the dural venous sinuses and congenital occipital dermal sinus, we examined both cases from an embryological viewpoint.

Arteriovenous Malformations↗

PubMed1994

The effects of a carotid-jugular fistula on cerebral blood flow in the cat: an experimental study in the acute period.

The purpose of the present study is to investigate the effects of feline carotid-jugular (CJ) fistula (Spetzler's model) on cerebral blood flow (CBF) in the acute period after creation of the fistula. Using laser-Doppler flowmetry, cortical CBF was measured on the fistula side of 11 cats. Temporary occlusion and opening of the fistula led to an immediate increase and decrease, respectively, in cortical CBF. However, CBF returned to baseline within 1 minute, on average. CO2 reactivity in the closed fistula was preserved. It is suggested that cerebral hemodynamic changes due to Spetzler's CJ fistula model are minimal in the acute period after fistulization.

Acute Disease↗

PubMed1994

Effects of acidic pH on the formation of vinblastine-induced paracrystals in Chinese hamster ovary cells.

The pH-related change in morphology of vinblastine (VLB)-induced paracrystals formed in Chinese hamster ovary (CHO) cells was examined immunohistochemically in order to determine both the mechanism of tubulin crystallization and the influence of acidic pHs on cytoskeletal microtubules. Lowering the extracellular pH (pHe) rapidly reduced the intracellular pH (pHi) in CHO cells. Lowering the pHi to near the neutral range significantly accelerated the growth of VLB-induced paracrystals, compared to that of paracrystals formed at a physiological pHe. However, further cytoplasmic acidification caused by the addition of sodium azide into the culture medium induced the disappearance of typical paracrystals and the appearance of a highly organized meshwork of tubulin appearing as short, thick filaments at the light microscopic level. Treatments using different concentrations of VLB at different pHe's showed that low pHi's (6.7 and 6.3) suppressed paracrystal-formation at lower concentrations of VLB (5 x 10(-6) M and 10(-5) M). At higher concentrations of VLB (5 x 10(-5) M and 10(-4) M), only short filaments were formed at pHi 6.3. Electron microscopy revealed that the filaments had a ladder-like structure probably consisting of a stacked series of fused rings. This indicates that paracrystals may be modified by extremely low pH. These results show that paracrystals are unstable in living cells and that their formation is regulated by environmental pH.

Acids↗

PubMed1994

Draining vein pressure increases and hemorrhage in patients with arteriovenous malformation.

BACKGROUND: Recent radiological studies have shown that arteriovenous malformations with impaired venous drainage may be susceptible to hemorrhage. To evaluate this hypothesis using a hemodynamic approach, we measured intravascular pressure during surgery in three patients with arteriovenous malformation. SUMMARY OF REPORT: In three patients we measured intravascular pressures in the draining venous system and the feeding arteries simultaneously before removal of arteriovenous malformations with marked segmental stenotic or occlusive draining veins and evidence of hemorrhage. The draining vein pressures at prestenotic (or preocclusive) sites in the three patients were 38, 25, and 40 mm Hg, respectively, all significantly above the normal cortical venous pressure, whereas pressure measurements in poststenotic sites and the sagittal sinus pressure in the venous drainage system approached normal values. The feeding artery pressures in the patients were lower than normal cortical artery pressure because of the arteriovenous shunt. CONCLUSIONS: Intraoperative vascular pressure measurements support the hypothesis that arteriovenous malformations with impaired venous drainage may be associated with a local increase in venous pressure and thus may be susceptible to hemorrhage.

Adolescent↗

PubMed1994

Aneurysmography for visualizing large aneurysms.

We report a case of a large cavernous sinus aneurysm, in which conventional angiography did not clearly demonstrate the exact form and the position of the neck. Superselective angiography performed with the catheter tip in the lumen of the aneurysm and with the internal carotid artery occluded just proximal to its neck is a new technique that demonstrates the morphological details of an entire aneurysm. With the use of cineangiography, the exact volume of the aneurysm was defined. The valuable aneurysmographic information obtained was useful in achieving occlusion of the aneurysm, while preserving the parent artery.

Carotid Artery, Internal↗

PubMed1994

Radiological study of symptomatic Rathke's cleft cysts.

We investigated the relationship between radiological findings and the nature of the cyst fluid and histological findings of six Rathke's cleft cysts. The results show that the majority (five of six cases) of symptomatic Rathke's cleft cysts exhibit no enlargement of the sella turcica on plain x-rays, which may be helpful in differentiating cystic pituitary adenoma in the radiological diagnostic process. Three cases with large cysts showing high-intensity T1-weighted magnetic resonance images harbored abundances of cholesterol crystal and hemosiderin pigment in the cyst walls. The high signal intensity in magnetic resonance images of Rathke's cleft cysts may be explained by hemorrhage and a deposition of cholesterol crystal and may be considered in certain cases of Rathke's cleft cyst, especially when they are large.

Adult↗

PubMed1994

Dural arteriovenous malformation involving the inferior petrosal sinus--case report.

A 59-year-old male presented with a dural arteriovenous malformation involving the inferior petrosal sinus manifesting as false-localizing ocular symptoms. Occlusion between the right inferior petrosal sinus and the right jugular bulb caused an unusual retrograde venous outflow from the inferior petrosal sinus to the cavernous sinus, thought to have been responsible for the chemosis, abducens nerve paresis, and orbital bruit. He was treated successfully with transarterial embolization and radiotherapy.

Cerebral Angiography↗

PubMed1994

Cerebral bacterial aneurysm and indications for cerebral angiography in infective endocarditis.

Six infective endocarditis patients who developed cerebral bacterial aneurysm were reviewed to clarify the indications and timing for cerebral angiography to achieve early detection of unruptured aneurysms. All cerebral bacterial aneurysms were confirmed either angiographically or at autopsy. All patients were treated conservatively. Four patients died due to ruptured aneurysm. Four of the six patients showed the signs and symptoms of cerebral and/or systemic embolism, followed by rupture or detection of cerebral bacterial aneurysm. Prodromal signs and symptoms of embolism in patients with infective endocarditis should be considered as indicators for cerebral angiography to detect cerebral bacterial aneurysms before rupture.

Adolescent↗

PubMed1994

Venous ischemia caused by dural arteriovenous malformation. Case report.

A case is presented of tentorial dural arteriovenous malformation (AVM) associated with visual hallucinations and quadrant hemianopsia. Computerized tomography (CT) and magnetic resonance imaging showed an ischemic region, mainly affecting the white matter of the right occipital lobe, that was defined as an area of increased blood volume on dynamic CT scans and as a decrease in cerebral blood flow on N-isopropyl-p-123I-iodoamphetamine single-photon emission CT scans. Angiography demonstrated venous congestion, probably because the retrograde arterial inflow from the dural AVM into the corticomedullary vein was direct and not via the sinuses. The symptoms and radiological findings improved immediately after endovascular treatment. The origin of these symptoms was fully evaluated and confirmed to be a reversible ischemic change caused by disturbance of the volume of venous return over an extensive area.

Aged↗

PubMed1994

Effect of intracellular pH and two growth factors, epidermal growth factor and human hepatocyte growth factor, on DNA synthesis in non-regenerating and regenerating hepatocytes and hepatoma cells.

I examined the effects of intracellular pH (pHi) and the growth factors, epidermal growth factor (EGF) and human hepatocyte growth factor (HGF), on DNA synthesis in non-regenerating hepatocytes, regenerating hepatocytes and hepatoma cells. Non-regenerating and regenerating hepatocytes were isolated from the livers of intact adult rat and of the adult rat 24 hours after 70% hepatectomy, respectively. Hep G2 cells, a human hepatoma cell line, was employed as hepatoma cells. Regenerating hepatocytes and Hep G2 cells, but not non-regenerating hepatocytes displayed increased DNA synthesis with increasing pHi in the absence of EGF and HGF. However, non-regenerating hepatocytes displayed little increase, regenerating hepatocytes displayed substantial increase in DNA synthesis with increasing pHi in the presence of EGF or HGF. In contrast, Hep G2 cells displayed decreased DNA synthesis in the presence of HGF but not EGF. These findings indicate that pHi influences the fashion of proliferation in hepatocytes and cancer cells. EGF and HGF stimulate DNA synthesis in hepatocyte and inhibit that in cancer cell, suggesting that increasing pHi and administration of these growth factors may be one of the effective treatment for hepatoma.

Animals↗

PubMed1994

[Venous angioma coexisting with other types of cerebrovascular malformations].

The authors report 3 cases in which, in addition to venous angioma, other types of vascular malformations coexisted. They discussed the pathological significance of this coexistence, and the treatment to be given in these conditions. Case 1: A 38-year-old man was admitted to the hospital because of progressive headaches of 3 days' duration. X-ray CT revealed a large hematoma in the left cerebellar hemisphere. Vertebral angiogram showed a caput medusae in the venous phase, which is a typical picture of venous angioma. The hematoma was surgically removed and careful inspection of the cavity wall was made. A thick vein and many thin walled dilated venules draining to the vein were observed in the cavity wall. These abnormal vessels were completely removed. Because of reaccumulation of the hematoma and massive edema of the hemisphere, reoperation was performed. On removing a part of the cerebellar hemisphere, a small mass of vascular network was found and removed together with the hematoma. Histologically, the first specimen was a typical venous angioma, and the second one was a arteriovenous malformation. Case 2: A girl 9 years of age was admitted because of headache and left sided ataxia. CT and MRI revealed a multi staged hematoma in the left cerebellar hemisphere. Vertebral angiography, however, failed to demonstrate any kind of vascular malformations. The hematoma was removed with its wall. The histological appearance was compatible with venous angioma. 4 years later she bled again, and reoperation was performed. Histological examination this time revealed a cavernous angioma.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

[Completely thrombosed large aneurysm of the distal middle cerebral artery: a case report].

A 19 year old male was admitted for evaluation after a seizure. Physical and neurological examination was normal. CT demonstrated an enlarged, high density mass in the right parietal lobe. MRI showed a homogeneous high intensity T1 weighted mass, surrounded by a low intensity T2 weighted rim in the right parietal lobe. Angiography did not show any abnormal findings. A diagnosis of cavernous angioma with primary bleeding in the subcortical region of the right parietal lobe was made after radiological examination. Histological examination showed a completely thrombosed aneurysm. The mechanism of the complete thrombosis and the growth of this large aneurysm and the shortcomings of radiological examination are discussed.

Adult↗

PubMed1994

[A case of acute cervical spinal epidural hematoma caused by extradural arterio-venous malformation].

The authors report a rare case of acute cervical epidural hematoma caused by the hemorrhage from extradural arterio-venous malformation. The patient was a 74-year-old Japanese man with a past history of total gastrectomy after being diagnosed as having gastric cancer 12 years before. Six hours prior to admission, the patient had experienced a sudden episode of severe nuchal pain radiating to both scapular areas, followed by rapid development of left-side Brown-Sequard Syndrome below the C4 cord level, and urinary incontinence. Plain cervical X-ray films did not show any destructive lesion suggesting a metastatic tumor. T1 and T2 weighted images of MRI demonstrated a high intensity mass lesion, suggesting an acute epidural hematoma, extending from C3 to C6 and compressing severely the left side spinal cord posteriorly. Twelve hours after the onset of symptoms, emergency laminectomy from C3 to C6 was performed and a fresh epidural clot with small vascular tissue was totally removed. Histological examination of the small vascular tissue in the hematoma revealed arterio-venous malformation. The postoperative recovery of the patient was dramatic. He regained full muscle strength and there was complete disappearance of sensory deficits 2 weeks after the operation. Although acute spinal epidural hematoma caused by extradural arterio-venous malformation is a rare clinical entity, MRI is the most helpful diagnostic tool for this condition. It should be stressed that accurate neuroradiological diagnosis and prompt surgical decompression of the spinal cord are essential to obtain an excellent surgical outcome.

Acute Disease↗

PubMed1994

[Recurrent meningioma with malignant transformation: a case which changed from meningothelial type to papillary type].

We report here a case with meningioma showing malignant transformation in its course of multiple recurrences. A 59-year-old woman developed a right-sided hemiparesis in June, 1982 and CT scan disclosed a parasagittal well-enhanced mass. The tumor was subtotally removed (Simpson grade III) by an operation in September, 1982. Histological findings of the tumor were consistent with a meningothelial meningioma but showed no malignant features, such as high cellularity, necrotic foci, high mitotic rate, or nuclear pleomorphism. However, the tumor did invade the underlying cerebral cortex. In August, 1986, a recurrent tumor was detected by CT scan and was removed (Simpson grade III). The tumor tissue at the second operation showed the same histological features as the first specimen. In September, 1990, the patient developed multiple intracranial recurrences. There were three tumor nodules, all of which were removed. Histologically, significant histological differences between the second and the third operative specimens were found. In the last tumor tissue, one nodule showed a papillary pattern. In the other tumor nodules, each tumor cell had proliferated separately instead of adhering to other tumor cells to form a syncytium. This histological pattern was consistent with an epithelial meningioma described by Cushing and Eisenhardt in 1938. The papillary portion of the tumor was stained with monoclonal antibody Ki-67 in frozen section. The labelling index was 9.7%, which was as high as malignant meningioma. Electron microscopic examination of the papillary portion of the tumor showed that the tumor cells had irregular nuclei, interdigitations between the adjacent plasma membranes and a few ill-developed desmosomes.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗

PubMed1994

[Bronchial carcinoid tumor with multiple brain metastasis].

Carcinoid tumor is regarded as a tumor with low grade malignancy, mostly originating from the gastrointestinal tract with little danger of metastasis. The authors encountered a very rare case of bronchial carcinoid tumor that had multiple metastasis to the intracranial space. The characteristics of radiological and hormonal examinations of this tumor are reported and discussed. The patient was a 73-year-old woman who gradually developed unsteadiness in walking and somnolence in daytime one month prior to admission. Those symptoms were aggravated and she began to vomit. On admission, neurological examination showed slight ataxia of left upper and lower extremities and dominant truncal ataxia. Chemical and hormonal examinations of blood and urine showed, gastrin was 230 pg/ml (37-172), ACTH was 67 pg/ml (< 60), serotonin was 565 ng/ml (53-200), and urinary 5-HIAA was 9.9 mg/day (0.8-4.8). Tumor markers (CEA, AFP, HGG, NSE) were all negative. Radiological examinations (chest X-P, CT scan) of her lung demonstrated a 3 x 3 cm tumor mass adjacent to the hilum of the left lower lobe. CT-scan of the head demonstrated cystic tumor in the vermis of the cerebellum (3 x 3 cm), the right posterior parietal lobe and the right temporal lobe. The wall of each tumor was enhanced by contrast medium. T1 weighted MRI demonstrated the walls of cystic tumors as iso intensity and the contents as low and high intensity with niveau formation. Little edema was recognized around the tumors. The wall of each cystic tumor was enhanced by Gd-DTPA.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1994

An unruptured arteriovenous malformation with edema.

We report a case of unruptured arteriovenous malformation in which an extensive zone of increased signal intensity in the brain parenchyma adjacent to the nidus is demonstrated on T2-weighted MR. This area of perilesional hyperintense signal exerts a compressive effect, suggesting that it represents perilesional edema.

Brain Edema↗