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Biomedical subjects

S Hirai

Publications and source records attributed to S Hirai.

At least 163 records · Page 9Linked to original sources

Abnormal cerebral perfusion in chronic methamphetamine abusers: a study using 99MTc-HMPAO and SPECT.

1. Cerebral blood flow of nine methamphetamine abusers with technetium-99m-hexamethylpropyleneamine oxime (HMPAO) and single photon emission computed tomography (SPECT) as well as morphological examination with magnetic resonance imaging (MRI) were investigated. 2. Six of these subjects exhibited multiple focal perfusion deficits in cerebral cortices without abnormalities in MRI including cerebral atrophy and/or infarctions. 3. Cerebral perfusion deficits were detected in methamphetamine abusers even after a long abstinence period, suggesting that vascular changes were irreversible to some degree. 4. HMPAO SPECT study appeared to be sensitive to the detection of cerebral perfusion abnormalities in drug abusers.

Adolescent↗

Suppressive effect of tetraprenylacetone on gastric atrophy induced by short-term administration of N-methyl-N'-nitro-N-nitrosoguanidine in rats.

BACKGROUND: Several studies have been reported on the effects of various therapeutic agents in enhancing or suppressing the carcinogenic activity of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). However, it is still unknown whether a mucosal protective agent could suppress its carcinogenic activity. METHODS: Twenty-five Wistar male rats were divided into four groups: group 1, MNNG alone; group 2, MNNG + tetraprenylacetone; group 3, control; group 4, tetraprenlacetone alone. MNNG 100 mg/mL, was freely given to groups 1 and 2, and tetraprenylacetone (200 mg/kg intraperitoneal) was additionally administered every other day to the rats in groups 2 and 4. The animals were sacrificed at 10 weeks and the gastric mucosa examined. RESULTS: Atrophic changes were observed in the antrum after 8 weeks of oral administration of MNNG. Furthermore, using immunohistological analysis with 5-bromo-2'-deoxyuridine (BrdU), the proliferative zone was found to be enlarged and shifted upward, although the BrdU labelling index of the proliferative zone was unaltered. Intraperitoneal administration of tetraprenylacetone every other day suppressed the MNNG-induced atrophic change and the alterations proliferative markers. Tetraprenylacetone alone did not have an effect either on morphological or proliferative markers. CONCLUSION: These observations suggest that gastric mucosal defensive factors may play critical roles in suppressing atrophic change inducing carcinogenesis by an exogenic carcinogen.

Animals↗

Differential expression of MART-1 in primary and metastatic melanoma lesions.

Twenty-eight primary and 29 metastatic melanoma lesions and 18 pigmented nevi lesions were analyzed by using the immunoperoxidase reaction with anti-MART-1 and anti-gp100 monoclonal antibodies (mAbs). The MART-1 was expressed in 28, 29, and 18, and gp100 was expressed in 27, 28, and eight of these lesions, respectively. Intensity and percentage of stained cells with anti-MART-1 mAb were stronger and higher than those with anti-gp100 mAb. MART-1 was expressed homogeneously in primary melanoma and pigmented nevi, whereas it was heterogeneously expressed in metastatic melanoma lesions. The level of expression of MART-1 in primary melanoma lesions did not correlate with any clinicopathologic parameters. These results suggest that anti-MART-1 mAb is a useful tool for immunohistochemical analysis of melanocytic lesions and also is useful for patients' selection and monitoring of antigen-loss variants in clinical trials with the MART-1-based immunotherapy.

Adult↗

Cellular proliferation and differentiation in rat atrophic gastric mucosa induced by N'-methyl-N'-nitro-N-nitrosoguanidine.

It has been demonstrated that mucosal cell proliferation in atrophic gastritis is significantly accelerated, although the dynamics of the cell proliferation and differentiation have not been well characterized. We sequentially analyzed the markers of proliferation and differentiation of rat atrophic gastritis induced by MNNG. Immunohistochemical staining by anti-BrdU, anti-PCNA, and anti-PDGF-BB antibodies demonstrated that cell proliferation in atrophic gastritis was accelerated not only in the parenchymal tissue but also in the mesenchymal tissue. Expression of a gap junction protein (connexin 32), which is a marker for differentiation of epithelial cells, was reduced during the progression of atrophy. Some apoptotic cells were observed in the lower to middle third of the atrophic mucosa, whereas apoptotic cells were rarely seen in normal mucosa, which suggests that apoptosis in these parts of the mucosa may be related to the occurrence of mucosal atrophy.

Animals↗

Apolipoprotein E accumulates with the progression of A beta deposition in transgenic mice.

To study the role of apolipoprotein E (apoE) in vivo in deposits of amyloid beta protein (A beta), a major component of senile plaque amyloid in the brain of patients with Alzheimer disease, the transgenic mice were examined by apoE immunostaining. The mice were systemically overexpressing signal peptide and 99 amino acid residues of the carboxy-terminal fragment of human amyloid beta protein precursor (betaAPP) under control of the powerful cytomegalovirus enhancer/chicken beta-actin promotor. A beta deposits appeared at 4 months and increased with aging in the acinar cells of the transgenic pancreas. Similarly, apoE deposits appeared in the pancreatic acinar cells at 4 months old. The number and size of apoE deposits increased with aging and correlated with the progression of A beta deposits. Interstitial macrophages labeled by apoE immunostaining appeared at 8 months after birth and their number increased with aging. On serial section of the pancreata of 24-month-old mice, approximately 70% of A beta deposits were labeled with the apoE antiserum. ApoE was detected in the highly insoluble formic acid fraction of the transgenic pancreas by an immunoblot study. The Northern blot study revealed no increase in synthesis of endogenous apoE mRNA. These findings indicate that apoE is closely related to progression of A beta deposits with aging and suggest that A beta deposition in the transgenic pancreas is similar to that in the senile plaque of Alzheimer brains. Therefore, our experimental system using transgenic mice will provide a useful tool to analyze the molecular mechanism of A beta deposition in association with apoE in vivo.

Aging↗

Serum levels of sICAM-1 and 5-S-cysteinyldopa as markers of melanoma progression.

The serum levels of the soluble form of intercellular adhesion molecule-1 (sICAM-1) and 5-S-cysteinyldopa (5-S-CD) were determined by double determinant immunoassay and high-performance liquid chromatography, respectively. Fifty-three melanoma patients (stage 1, 12 patients; stage II, 11; stage III, 19; and stage IV, 11; total number of samples, 116) and 31 age- and sex-matched healthy control subjects were analysed. Both the sICAM-1 and 5-S-CD levels were significantly higher in stage IV patients than those in stage I, II and III patients (sICAM-1; all P < 0.001; 5-S-CD; all P < 0.05). The serum levels of 5-S-CD were elevated only in stage IV patients. sICAM-1 levels elevated gradually with disease progression. Testing of sequential bleedings showed that both sICAM-1 and 5-S-CD levels were elevated in most of the patients whose disease had progressed. However 5-S-CD levels were not elevated in those patients whose metastases were amelanotic. There was a statistically significant correlation between sICAM-1 and 5-S-CD levels (R = 0.6 55, P < 0.001). Serum levels of 5-S-CD may be a useful parameter for monitoring the clinical course of the disease in patients whose metastases are melanotic. Analysis of both sICAM-1 and 5-S-CD levels in serum will contribute greatly to monitoring the clinical course of melanoma patients.

Adolescent↗

Molecular genetic analysis of HLA class II alleles in Japanese patients with melanoma.

Distribution of HLA-DQA, -DQB and -DPB alleles in ninety-six Japanese patients with melanoma was analyzed using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, and the association between clinical parameters and the presence of certain HLA class II alleles investigated. The frequency of HLA-DQB1*0302 was increased, while those of DQA1*0101(04), -DQA1*0401 and DRB1*0802 were decreased in melanoma patients compared with controls. Moreover, the frequency of HLA-DQA1*0103 in patients with acral lentiginous melanoma was increased compared with controls. However, none of these HLA class II alleles showed significant positive or negative associations after correction of the P value. In addition, there was no correlation between these antigens and clinical parameters. These results indicate that HLA class II alleles may not contribute to a strong susceptibility to melanoma in the Japanese.

Adult↗

Development of an intravascular pumping oxygenator using a new silicone membrane.

A new intravascular pumping oxygenator (IVPO) was developed for intravascular gas exchange and circulatory assistance in critically ill patients with respiratory and circulatory failure. The IVPO utilizes new silicone hollow fibers (diameter, 1 mm; membrane width, 50 microns) and consists of two driving tubes for the oxygenation and pumping of circulating blood. The performance characteristics of the IVPO were studied using an experiment ex vivo model. With a mean hemoglobin concentration of 10.5 +/- 2.3 g/dl, total oxygen transfer was 5.6 +/- 1.5 ml/min at a blood flow of 200 ml/min and 6.3 +/- 2.2 ml/min at a blood flow of 250 ml/min. Total CO2 transfer was 3.8 +/- 1.4 ml/min at a blood flow of 200 ml/min and 4.2 +/- 1.6 ml/min at a blood flow of 250 ml/min. Blood flow increased to a maximum of 250 ml/min during IVPO pumping. This preliminary experiment demonstrated that the IVPO has the capacity to function both as circulatory assist pump and as an intravascular hollow fiber oxygenator.

Animals↗

Trial manufacture of eccentric roller type total artificial heart.

Working toward a completely implantable total artificial heart, we have designed an eccentric roller type total artificial heart. The actuator of this artificial heart is a drum type eccentric roller that squeezes the blood chambers. The blood chambers are made of silicone rubber and are torus in shape. The shape of the artificial heart is an almost circular cylinder, and its length and diameter are 10 cm and 8 cm, respectively. The 2 main characteristics of this artificial heart are that it discharges blood in a pulsatile mode and that it requires no reversing of the motor. Because we have not completed the artificial heart yet, we have tested the eccentric roller mechanism on the prototype with an overflow type mock circulation with a 100 mm Hg afterload. The prototype worked at the roller speeds of 50, 100, and 150 rpm with flow rates of 1.7, 3.7, and 5.4 L/min, respectively. Next the prototype was connected to a Donovan type mock circulatory system and worked at roller speeds of 88-214 rpm with flow rates of 3.0-8.4 L/min against mean afterloads of 82-120 mm Hg.

Biocompatible Materials↗

Right atrial separation procedure for eliminating chronic atrial fibrillation associated with atrial septal defect.

Chronic atrial fibrillation (AF) had been documented in a patient with atrial septal defect for 7 years. A right atrial separation procedure was performed for ablation of chronic AF, concomitant with repair of the atrial septal defect, and followed by atrial electrophysiological mapping. A horizontal transectional incision extending to the borders of the atrial septum and the tricuspid annulus was made. Cryolesions of the atrial isthmus between the margin of the upper incision and the tricuspid valve annulus were created at -60 degrees C for 2 minutes at a time. After the operation, the patient had restored normal sinus rhythm during a subsequent follow-up period of 48 months.

Atrial Fibrillation↗

Effects of MRI abnormalities on WAIS-R performance in solvent abusers.

OBJECTIVE: To clarify how chronic solvent abuse affects cognitive function using magnetic resonance imaging as an index of brain damage. MATERIAL AND METHODS: A total of 25 chronic solvent abusers underwent magnetic resonance imaging with quantitative neurometry and Wechsler Adult Intelligence Scales revised. RESULTS: The abusers with white matter change (n=10) showed significantly (P<0.05) lower performance IQ, especially in Digit Symbol subtest (P<0.01). Also, the severity of pontine atrophy was significantly correlated with PIQ (r=0.60, P<0.01). CONCLUSIONS: These data indicate that solvent abuse causes the decline in the test performance reflecting cognitive and fine motor dysfunction and that white matter changes and pontine atrophy may have some roles in this decline.

Adult↗

Spontaneous haemothorax associated with von Recklinghausen's disease: review of occurrence in Japan.

The case history is presented of a 61 year old man with von Recklinghausen's disease who developed a spontaneous haemothorax. In spite of being asymptomatic for five days after drainage, he died as a result of fatal sudden re-bleeding. The post mortem examination showed dissection and rupture of the left subclavian artery. Microscopically, disarrangement of smooth muscle and decrease of elastic fibre was observed in the ruptured artery. Haemothorax in patients with von Recklinghausen's disease may require thoracotomy, even if the condition of the patient appears to be stable.

Drainage↗

[Cerebral perfusion and oxygen metabolism in Parkinson's disease: positron emission tomographic study using oxygen-15-labeled CO2 and O2].

In many previous studies, positron emission tomography (PET) has been used to evaluate cerebral perfusion and oxygen metabolism in Parkinson's disease. In this article, these previous reports are reviewed together with our recent findings. Hypoperfusion and hypometabolism in parkinsonian brains reported previously seemed to be derived chiefly from psychiatric manifestations, including intellectual decline and depression. In our study on 34 patients with asymmetric symptoms, the blood flow and oxygen metabolism were significantly higher in the caudate head and putamen, contralateral to the predominant patient's symptoms, than in the opposite nuclei. The asymmetry in the perfusion and metabolism is clearer in the early stage of the disease or in patients without DOPA therapy. These findings suggest that the striatal dysfunction is caused by uninhibited activities, supersensitivities, or compensatory hyperactivities of the striatum.

Brain↗

[A 29-year-old man with diabetes insipidus and cerebellar ataxia and development of spinal cord swelling 15 years after the onset].

We report a 29-year-old man with diabetes insipidus and cerebellar ataxia who developed spinal cord swelling 15 years after the onset. He was well until 14 years of the age when he noted dizziness. Two years after there was an onset of gait disturbance and slurred speech. He also noted polydipsia and polyuria. He was evaluated at the neurosurgery service of our hospital when he was 17 years of the age. Neurologic examination at that time revealed memory loss, horizontal nystagmus, cerebellar ataxic gait, dysmetria and decomposition more on the left. Cranial CT scan revealed a mass lesion involving the left subthalamic region and the head of the caudate area. Spinal fluid was unremarkable, however, human chorionic gonadotropin was increased to 27 mIU/ml. He was treated by radiation therapy (3,000 rads for total brain area and 5,460 rads for focal region). His CT scan and memory loss improved, however, cerebellar ataxia was unchanged. Three years after the radiation, he started to show choreic movement in his neck and left upper extremity. He was admitted to our service in August 14, 1995 when he was 29 years of the age. On admission, he was alert but disoriented to time; calculation was also poor. Higher cerebral functions were intact. The optic fundi were normal without papilledema. Visual field appeared intact. Gaze nystagmus was observed in all the directions, but more prominent in the horizontal direction. Speech was slurred. Otherwise, cranial nerves were unremarkable. Motor wise, he showed marked truncal and gait ataxia; he was unable to walk because of ataxia. Muscle atrophy and marked weakness was noted in both upper extremities more on the left side. Deep tendon reflexes were diminished in the upper extremities but active in the lower extremities. He was polyuric; urinary specific gravity was low. Spinal fluid contained 6 cells/cmm and 113 mg/ dl of protein; Queckenstedt was positive. MRI revealed swelling of the cervical cord; in addition, the entire cervical region and the medullar oblongata appeared as high signal intensity areas. No mass lesion was noted in the supratentorial structures but the third ventricle was markedly enlarged. Surgical biopsy was performed on the cervical lesion. The patient was discussed in neurologic CPC, and the chief discussant arrived at the conclusion that the patient had germinoma with syncytiotrophoblastic giant cells in the diencephalic region which appeared to have been cured by radiation therapy; he thought that the cervical lesion was the seeding of germinoma. Cerebellar ataxia was ascribed to the remote effect of germinoma. Most of the participants thought that the original tumor was germinoma and the cervical lesion was its spread. Some participants thought that his ataxia was caused by germinoma cells involving the medulla and the inferior cerebellar peduncles. Histologic observation of the biopsied tissue from the spinal cord revealed the typical two cell patterned germinoma. Most of the tumor cells were not stained for an antibody against HCG, but some tumor cells were positively stained. Germinoma is very radio-sensitive; this patient showed T2 high signal lesion involving the medulla oblongata and cervical cord continuously. Probably, tumor cells in the lower brain stem escaped radiation, and gradually spread to the spinal cord over many years. At the time of operation, the surface of the spinal cord was free from tumor cells. Therefore, tumor cells invaded the spinal cord continuously from the medulla oblongata. He was treated with cervical radiation, and his neurologic as well as radiologic findings showed marked improvement.

Adult↗

[Sibling cases of opsoclonus-polymyoclonus syndrome].

We described a 34-year-old man who developed opsoclonus-polymyoclonus syndrome (OPS) associated with benign encephalitis. His older sister also suffered from the same syndrome 12 years ago. We examined HLA types in 6 patients with OPS who were admitted to our hospital, including these sibling cases. All 6 patients have type A2 antigen and statistical analysis suggested that there is a positive relationship between OPS and HLA A2 antigen. Considering the two facts that the existence of the sibling cases in this relatively rare disorder and sharing of HLA A2 antigen in our 6 cases, some genetic factors might be involved in the development of OPS.

Adult↗

[Dural arteriovenous malformation presenting venous ischemia].

We report three patients with dural arteriovenous malformation (DAVM) in the posterior fossa presenting the venous ischemia and the pathophysiology and the clinical characteristics of DAVM presenting the venous ischemia are discussed. Associated with occlusive changes in the venous sinuses, DAVM in the posterior fossa develops the venous hypertension of the straight sinus and the venous ischemia of cerebral white matter and basal ganglia. The venous ischemia presents progressive symptoms consisting of dementia with or without the ensuing consciousness disturbance. Multiple parenchymal lesions and abnormally dilated and tortuous veins are the characteristic findings in MRI/CT.

Brain Ischemia↗

[Iodine 123-labeled meta-iodobenzylguanidine myocardial scintigraphy in the cases of idiopathic Parkinson's disease, multiple system atrophy, and progressive supranuclear palsy].

A 20-25% rate of antemortem misdiagnosis of idiopathic Parkinson's disease (PD) suggests that it may be difficult to clinically differentiate PD from other degenerative diseases of the central nervous system, such as progressive supranuclear palsy (PSP) or multiple system atrophy (MSA). Iodine-123 meta-iodobenzylguanidine ([123I] MIBG), an analogue of norepinephrine, is a tracer for functioning of sympathetic neurons. To investigate cardiac sympathetic function in PD, MSA, and PSP, [123I] MIBG myocardial scintigraphy was performed in 25 patients with PD, 25 patients with MSA, 14 patients with PSP, and 20 control subjects. In planar imaging studies, the heart-to-mediastinum average count ratio (H/M) was calculated for both early and delayed images. The mean value of H/M in patients with PD was significantly lower than in those with MSA, PSP, or no disease (p < 0.0001). Regardless of disease severity or intensity of anti-parkinsonian pharmacotherapy, mean values for H/M were always low in patients with PD. The mean values of H/M in patients with MSA and PSP were significantly lower than in controls (p < 0.01). There was no significant difference between the mean value of H/M in MSA with orthostatic hypotension (OH) and that in MSA without OH, and also there was no significant difference between the mean value of H/M in MSA with striatonigral degeneration and that in MSA with olivopontocerebellar atrophy. Although the mean value of H/M in PSP with amitriptyline treatment was significantly lower than that in PSP patients without amitriptyline treatment (p < 0.005), there was no significant difference between the mean value of H/M in PSP patients without amitriptyline treatment and that in controls. There was no correlation between H/M and disease duration in those three akinetic-rigid disorders that we have studied here. Thus, PD may have an abnormality of cardiac sympathetic function which has not been detected by previous cardiovascular autonomic studies. Particularly in early stages, [123I] MIBG myocardial scintigraphy may help to differentiate PD from MSA and PSP.

3-Iodobenzylguanidine↗

[Uncoupling of cerebellar blood flow and metabolism in paraneoplastic cerebellar degeneration: report of a case].

We report a 65-year-old woman with paraneoplastic cerebellar degeneration (PCD) who showed reduced cerebellar metabolism with preserved blood flow. She was admitted to Gunma University Hospital because of progressive gait and speech disturbances. Neurologic examination revealed nystagmus, dysphagia, explosive speech, reduced muscle tone in limbs, and marked truncal and limb ataxia, and mild hypesthesia in hands and feet. Cranial MRI demonstrated slight cerebellar atrophy. Laboratory findings disclosed high levels of serum CA19-9 and other tumor markers, and positive anti-Yo antibody, indicating that she had PCD. A specimen obtained from an axillary lymph node revealed metastasis of poorly differentiated adenocarcinoma, although systemic and vigorous checkup failed to find its origin. Cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) were measured using positron emission tomography (PET) 15 months after the onset. CMRO2 was clearly decreased in the cerebellum, while CBF was almost normal. Moreover, PET with 2 18F-fluoro-2-deoxy-D-glucose (FDG) revealed that glucose metabolism was also reduced in the cerebellum. Single photon emission tomography using 99mTc-ethyl cysteinate dimer (ECD) showed a normal blood flow pattern in the whole brain. These results indicated that uncoupling of circulation and metabolism in the cerebellum of this patient. There are several reports showing uncoupling of cerebral perfusion and metabolism in ischemic disorders, encephalitis, mitochondrial diseases, brain tumors, epilepsy and Gaucher disease, although its pathophysiology is not elucidated. Because anti-Yo antibody evidently gives a suppressive influence on the cerebellar neurons, understanding the way the autoantibody acts may give a clue to the mechanism of reduced cerebellar metabolism with preserved perfusion in PCD.

Adenocarcinoma↗