PubMed Health⌕ Search

Biomedical subjects

M Kameyama

Publications and source records attributed to M Kameyama.

At least 19 recordsLinked to original sources
PubMed1992

ET-1 induced bronchoconstriction in the early phase but not late phase of anesthetized dogs is inhibited by indomethacin and ICI 198615.

Intratracheally injected or aerosolized ET-1 induced quick and long-lasting bronchoconstriction of anesthetized mongrel dogs, thus increasing respiratory resistance(Rrs) with concomitantly decreasing dynamic compliance(Cdyn). As collateral resistance(Rcs) was measured postexposure to aerosolized ET-1 using wedged bronchoscope technique, ET-1 increased Rcs in a dose and time dependent manner. The increase attained maximal in 2 min and then, gradually declined. When the dogs were pretreated with the intravenous injection of 0.1 micrograms/kg ICI 198615, an inhibitor of lipoxygenase, the constrictive response was slowed down. Essentially similar results were also observed with the intravenous injection of 5 mg/kg indomethacin. Our observations suggest that the early phase of the ET-1 induced bronchoconstriction is mediated by eicosanoid metabolites.

Anesthesia, Intravenous↗
PubMed1992

Metabolic changes of glioma following chemotherapy: an experimental study using four PET tracers.

To shed light on the metabolic changes in glioma following therapy, uptake changes among 18F-fluoro-2'-deoxyuridine (18FUdR), 14C-thymidine (dThd), 14C-methionine (Met) and 3H-deoxyglucose (DG) in glioma model after chemotherapy were studied, as a means for interpreting clinical PET results, together with the changes in the bromodeoxyuridine (BUdR) labeling index. 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(-2chloroethyl)-3-nitro sourea hydrochloride (ACNU) was administered intraperitoneally in the tumor-bearing rats and uptake of the tracers or BUdR labeling index in tumor tissue were measured. The metabolic response following chemotherapy was a sharp fall immediately for 14C-dThd and 18FUdR and a moderate fall for 14C-Met whereas there was a fall in 3H-DG from 1 week after chemotherapy. The changes of BUdR labeling index paralleled that in the uptake for dThd and FUdR. These result indicate that PET scans using a variety of tracers in conjunction could be used for clinical diagnosis and evaluation of therapy in glioma cases. 18FUdR is a promising tracer of nucleic acid metabolism to evaluate the proliferative potential of brain gliomas.

Animals↗
PubMed1992

Dynamic study of methionine uptake in glioma using positron emission tomography.

In order to evaluate the methionine uptake of a glioma with positron emission tomography (PET), the kinetics of carbon-11 methionine was investigated in 11 patients by measuring the free 11C-methionine in plasma as an input function following intravenous administration. When the mean clearance curve of free 11C-methionine in plasma instead of individual 11C-methionine clearance curves was used, mean differences in uptake rate and distribution volume were 4.0% and 4.6% respectively. By applying the mean clearance curve of free 11C-methionine in 18 glioma patients, significant differences in 11C-methionine uptake rate and distribution volume were found according to pathological grading. For the accurate evaluation of the metabolism of 11C-methionine, it is therefore preferable that the actual level of free 11C-methionine in the plasma be measured, especially for the follow-up of individual cases. The study also demonstrated that the mean clearance curve of 11C-methionine in plasma might be employed as an input curve for calculating the uptake rate and distribution volume with small errors.

Adult↗
PubMed1992

Cerebral blood flow and oxygen metabolism in infants with hydrocephalus.

In this study, regional cerebral blood flow (rCBF) and the cerebral metabolic rate of oxygen (rCMRO2) were measured using positron emission tomography (PET) with oxygen-15 radiopharmaceuticals to clarify the pathophysiology of ventriculomegaly in the developing brain. Four hydrocephalic infants without severe neurological deficit were studied. Hypoperfusion was observed in the frontal, parietal, and visual association cortices which surrounded dilated anterior or posterior horns of the lateral ventricle. Lower rCMRO2 values than adult rates were observed in all cases. In the infants with markedly enlarged anterior or posterior horns, the surrounding cortices showed relatively lower rCMRO2 values with the fall of rCBF. Postoperative studies were performed in two infants. rCMRO2 increased in every region after ventriculoperitoneal shunting, but little change was observed in rCBF. These results indicate that metabolic deterioration occurs in the developing brain with hydrocephalus.

Blood Volume↗
PubMed1992

MRI and SPECT findings in amyotrophic lateral sclerosis. Demonstration of upper motor neurone involvement by clinical neuroimaging.

MRI was performed in 21 patients and single photon emission computed tomography (SPECT) with N-isopropyl-p-123I iodoamphetamine in 16 patients, to visualize upper motor neurone lesions in amyotrophic lateral sclerosis. T2-weighted MRI revealed high signal along the course of the pyramidal tract in the internal capsule and cerebral peduncle in 4 of 21 patients. SPECT images were normal in 4 patients, but uptake was reduced in the cerebral cortex that includes the motor area in 11.

Adult↗
PubMed1992

Accessory nerve neuroma presenting as recurrent jugular foramen syndrome.

We report a patient with spontaneous recovery and recurrence of a jugular foramen syndrome secondary to an accessory nerve neuroma. He showed sudden onset of unilateral palsy of the ninth, tenth and eleventh cranial nerves in 1982. He recovered almost fully and in 1990 the palsies recurred. MRI revealed a small mass in the right jugular foramen. The tumour was resected via suboccipital craniectomy, and diagnosed as a neuroma of the eleventh cranial nerve.

Accessory Nerve↗
PubMed1992

Profound vasoconstrictive effect of cigarette smoking in diabetics with autonomic neuropathy.

Changes in leg skin temperature during and after cigarette smoking were examined in 25 diabetics with autonomic neuropathy (au-neuropathy) (mean age 52 +/- 2 years) and 23 without (mean age 49 +/- 2 years), and 15 normal controls (mean age 49 +/- 2 years) using a Thermoviewer JTG 3300. All subjects were habitual smokers. Japanese Seven Star cigarettes (each containing 1.2 mg nicotine) were used for the test. Tender brand cigarettes (0.3 mg) were used additionally to compare the effect of nicotine content on the results. The smoking-stimulated thermographic pattern in the control group was rather flat, with a slight decrease in temperature followed by a slight increase before returning to the baseline level 15-20 min after smoking. The frequency of the typical temperature decreasing pattern, characterized by a profound decrease and gradual return to the baseline level in about 1 h, was significantly higher in the diabetic group than in the control group (33/48 vs 1/15; P less than 0.005). A comparison of the two diabetic subgroups revealed that the frequency was considerably higher in the subgroup with au-neuropathy (23/25 vs 10/23). These results suggest that au-neuropathy affects smoking-induced vasoconstriction in diabetic subjects. The maximum temperature decreases recorded were 1.5 +/- 2.0 and 2.69 +/- 0.24 degrees C in the controls and diabetics with au-neuropathy, respectively. The effect of Tender cigarettes with a low nicotine content was much weaker than that of Seven Star, which further suggests that smoking-induced vasoconstriction was also nicotine-dependent.

Diabetic Angiopathies↗
PubMed1992

Tumor diagnosis by PET: potential of seven tracers examined in five experimental tumors including an artificial metastasis model.

The potential of seven tracers for the metabolic imaging of tumors by positron emission tomography was studied using five experimental tumor models. The tracers examined were 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG), 2-deoxy-2-[18F]fluoro-D-galactose (2-[18F]FdGal) and 2-deoxy-2-[18F]fluoro-L-fucose (2-[18F]FdFuc) for investigating energy metabolism. L-[methyl-11C]Methionine ([11C]Met) and 6-[18F]fluoro-L-fucose (6-[18F]FFuc) were used for assessing protein and glycoprotein synthesis, while [3H]thymidine ([3H]Thd) and 2-deoxy-5'-[18F]fluorouridine ([18F]FdUrd) were used to investigate nucleic acid metabolism. The highest mean uptake by the five different tumors was found for [3H]Thd, followed in order by [18F]FDG, [11C]Met, 2-[18F]FdGal, [18F]FdUrd, 2-[18F]FdFuc and 6-[18F]FFuc. The tumor-to-tissue uptake ratios indicated that the nucleosides, [11C]Met and 6-[18F]FFuc were better tracers in the brain region. All the tracers except for the fucose analogs were suitable for the thoracic region, while [11C]Thd and [18F]FDG were superior in the abdominal region. In comparison with the primary tumor model of Lewis lung carcinoma (3LL), [3H]Thd uptake in the artificial metastatic 3LL model showed the maximum enhancement, followed by [18F]FDG, [11C]Met and the other tracers. The [18F]FDG uptake correlated with the [3H]Thd uptake. [18F]FdUrd, 6-[18F]FFuc and 2-[18F]FdGal could be used for distinguishing different types of tumors. The combined use of these radiotracers can possibly allow the assessment of tumor metabolism, and this indicates the viability of tumors.

Animals↗
PubMed1992

SPECT findings in Parkinson's disease associated with dementia.

Dementia in Parkinson's disease is thought to be attributable not only to subcortical lesions but also to cortical alterations, especially frontal lobe dysfunction. To evaluate cortical function, the regional cerebral blood flow (rCBF) was estimated of 13 demented and 13 non-demented age matched patients with Parkinson's disease compared with that of 10 age matched controls using I-123 iodoamphetamine single photon emission tomography (IMP-SPECT). The rCBF of the nondemented Parkinson's patients showed no significant differences from that of the control subjects. In the demented patients, the bilateral frontal and parietal and left temporal regional blood flow was significantly less than in the controls. Four demented patients showed isolated frontal hypoperfusion, 8 showed fronto-parietal hypoperfusion, and 1 showed isolated parietal hypoperfusion. Frontal hypoperfusion was therefore present in 12 of the 13 demented patients, and this finding agrees with the frontal lobe dysfunction hypothesis. Parietal rCBF had a significant positive correlation with cortical functions such as calculation and language ability in the MMSE scores. The parietal and temporal reduction in rCBF probably reflects the presence of Alzheimer pathology, cortical Lewy body disease, or both.

Aged↗
PubMed1992

Sphenoid sinus mucocele with recurrent visual disturbance.

We present a case of sphenoid sinus mucocele with recurrent visual disturbance on the same side. A 22-year-old female showed two episodes of visual disturbance in the left eye for 3 months, and acute retrobulbar optic neuritis was diagnosed. With corticosteroid, visual disturbance improved in 1 week. MRI and CT scans showed mucocele in the left sphenoid sinus, and left optic nerve swelling with high intensity was observed in T2-weighted MRI. No destruction of the optic canal was found. The contiguous inflammation in the optic nerve rather than compression was considered as pathogenesis.

Adult↗
PubMed1992

Cerebral blood flow and metabolism following superficial temporal artery to superior cerebellar artery bypass for vertebrobasilar occlusive disease.

In order to clarify the effectiveness of extracranial-intracranial bypass operations in patients with vertebrobasilar occlusive disease, the authors used positron emission tomography to investigate the cerebral blood flow (CBF) and metabolism of eight patients undergoing superficial temporal artery (STA)-superior cerebellar artery (SCA) bypass procedures. In the preoperative studies, CBF in the region of the posterior fossa was low and the oxygen extraction fraction (OEF) was high, the so-called "misery perfusion syndrome." Such changes were evident in both the posterior circulation and the anterior circulation regions. Postoperatively, there was a significant increase in CBF, a significant decrease in the OEF not only in the region of posterior circulation but also over the entire brain, and a disappearance of the uncoupling between CBF and oxygen metabolism. The STA-SCA bypass procedure is effective in improving CBF and metabolism in patients with vertebrobasilar occlusive disease.

Arterial Occlusive Diseases↗
PubMed1992

Chiari malformation with compression of the medulla oblongata by the vertebral arteries. Case report.

A unique case is reported of Chiari malformation and compression of the medulla oblongata by both vertebral arteries. A 39-year-old woman complained of unsteady giant and motor weakness of the legs, and magnetic resonance imaging revealed the malformation and compression. Vascular decompression of the vertebral arteries was performed using synthetic (Gore-tex) vascular strips following posterior fossa decompression.

Adult↗
PubMed1992

[Isolated angiitis of the central nervous system with high immune complex titer, first presenting as intracranial hemorrhage during cesarean section].

A case of isolated angiitis of the central nervous system (IACNS) which first presented as intracranial hemorrhage during cesarean section was reported. The patient was a 27-year-old female who showed severe headache during cesarean section. CT scan disclosed hematoma in the right parieto-occipital area. Carotid and vertebral angiograms demonstrated striking areas of stenosis and irregularity of all intracranial arteries. There was no abnormality in the branches of the external carotid arteries. Systemic angiograms showed no evidence of systemic vasculitis. Biopsy of the temporal artery showed no abnormal findings. Titer of immune complex was elevated. Angiitis showed no improvement with corticosteroid alone, but improved markedly with corticosteroid plus cyclophosphamide. Elevated titer of immune complex became normal. Treatment with a combination of corticosteroid and cyclophosphamide is recommended in IACN.

Adult↗
PubMed1992

["Wrapping therapy" for advanced hepatic cancer with arterial and intraportal infusion chemotherapy].

A new treatment method to intercept collaterals using silicone rubber sheeting was used for 5 patients with advanced hepatic cancer. The therapy was carried out to prevent new collaterals. This procedure was followed by arterial chemoembolization, arterial infusion chemotherapy and intraportal infusion chemotherapy. The results were complete response in 2 patients, partial response in 2 patients, and no change in 1 patient. The overall survival time was 7-54 months after wrapping. Although a randomized control study is necessary to assess the true value of this method, the new therapy is considered worth using as an adjuvant treatment for advanced hepatic malignancies uncontrolled by arterial chemotherapy or chemoembolization.

Antineoplastic Agents↗
PubMed1992

[Regional therapy to prevent recurrence after surgery in hepatocellular carcinoma].

The significance of regional therapy to prevent recurrence after surgery for hepatocellular carcinoma (HCC) was evaluated. In 275 patients who underwent hepatic resection for HCC, 143 (52%) had recurrences. Post-recurrence survival of the patients with regional therapy for recurrent foci was significantly better than that of patients without such therapy. Five-year post-recurrence survival of the patients treated with second surgery (77%) was significantly better than that of patients treated with chemoembolization (17%). The difference in 5-year survival between the former and the latter seemed to be caused by the difference in the degree of tumor progression at the recurrence. A second hepatic resection was the treatment of choice for a solitary intrahepatic recurrent tumor. However, chemoembolization was recommended for two or more recurrent foci.

Carcinoma, Hepatocellular↗
PubMed1992

[Effect of enkephalinase inhibitor on endothelin-1 induced bronchoconstriction in guinea pigs].

Endothelin-1 (ET-1) is one of the most potent bronchoconstrictors in the guinea pig. The mechanism of its metabolism is still unclear. Phosphoramidon is known to be an enkephalinase inhibitor. We studied the effect of phosphoramidon on bronchoconstriction induced by ET-1. In the first in vitro study, a tracheal preparation was mounted in oxygenated Krebs-Ringer solution. The response was monitored by isometric transducer. Dose-response curves to ET-1 with or without phosphoramidon were obtained. Phosphoramidon potentiated ET-1 induced bronchoconstriction significantly. Next, the specific airway conductance (sGaw) was measured in conscious guinea pigs exposed to an aerosol of phosphoramidon or saline, followed by ET-1 aerosol inhalation. The ET-1 dose was increased by successively doubling the concentration. sGaw, after inhalation of phosphoramidon, was significantly reduced when exposed to ET-1. Phosphoramidon also potentiated ET-1 induced bronchoconstriction in vivo. Next, lung parenchymal tissues were prepared and placed in oxygenated Krebs-Ringer solution with or without phosphoramidon. ET-1 was added and incubated, and samples were injected into a high performance liquid chromatography column. Phosphoramidon inhibited an analysis of ET-1. These data suggest that enkephalinase plays a role in the break down of ET-1 in the airway of the guinea pig. Under the condition of decreased enkephalinase, ET-1 would potentiate bronchoconstriction.

Animals↗
PubMed1992

[Evaluation of radiation therapy combined with intra-arterial infusion chemotherapy in patients with non-resectable pancreatic cancer].

This is a retrospective study to evaluate arterial infusion chemotherapy and radiotherapy for non-resectable pancreatic cancer without liver metastasis. Intra-arterial chemotherapy of the pancreas was performed for 17 patients, and 5 additionally received irradiation therapy. Five patients received radiation therapy alone. Both pain relief and tumor-reduction were more successful compared to the systemic chemotherapy group. In the locoregional treatment group, the patient survival rate was 50% at 1 year and 16% at 2 years. These rates were significantly higher than in the systemic chemotherapy group (p less than 0.01). Among the locoregional treatment groups, the median survival period was 7 months in radiation alone, 12 months in intra-arterial chemotherapy group, and 11 months in intra-arterial chemotherapy plus radiation group. These results suggested that locoregional treatment for pancreatic tumor is effective in increasing survival period and improving the quality of life.

Angiotensin II↗