Biomedical subjects

S Asari

Publications and source records attributed to S Asari.

At least 19 recordsLinked to original sources

PubMed1992

Surgical management of the unruptured cerebral aneurysm accompanied by ischemic cerebrovascular disease.

Unruptured cerebral aneurysms accompanied by ischemic CVD in 16 patients were analyzed and their managements are discussed. Unruptured aneurysms of 8 patients with mild or no clinical symptoms and small low density areas on CT were treated surgically. There was no operative mortality, but postoperative complication occurred in two patients. Both were operated on through the ipsilateral side of ischemic lesions shortly after the onset of ischemic symptoms. Eight patients who had severe neurological deficits due to ischemic lesions and large low density areas on CT did not receive aneurysmal operation. When unruptured aneurysms are accompanied by ischemic CVD, the treatment should be determined by the severity of neurological deficits caused by ischemic CVD. If an unruptured aneurysm was the source of emboli resulting in the ischemic lesion, it should be operated. Careful manipulation is required during surgery, especially from the ipsilateral side of ischemic lesion.

Aged↗

PubMed1992

Trigeminal neurinoma presenting with intratumoral hemorrhage: report of two cases.

We report 2 cases of trigeminal neurinoma presenting with spontaneous intratumoral hemorrhage. There are only 2 similar cases reported in the literature. Presenting symptoms were headache, diplopia, disturbed consciousness and trigeminal disturbance with sudden onset. CT scan showed a typical fluid-fluid level within low-density mass in the cerebellopontine angle in one case. On MRI, one case showed a typical fluid-fluid level on T2-weighted image and another one had mixed signal intensities including hyper- and hypointensities on both T1- and T2-weighted images. Histologically, increased vascularity, consisting of dilated and thin-walled vessels presenting telangiectatic or cavernous angiomatous appearances were observed in the specimens in both cases. The size of these tumors was about 3 cm each in diameter. Risk factors for hemorrhage appear to be large tumor size and increased vascularity.

Aged↗

PubMed1992

Neurinomas presenting as spontaneous intratumoral hemorrhage.

Massive intratumoral or subarachnoid hemorrhage from neurinomas is very rare. The authors report on six patients, four men and two women, with neurinomas that presented as spontaneous intratumoral hemorrhage. The average age of the patients was 56.8 years (range, 31-74 years). Neurinomas originated from the acoustic nerve in four patients and from the trigeminal nerve in two. Four cases were accompanied by the sudden occurrence of clinical symptoms such as headache, double vision, and hemisensory or motor disturbance. The maximum diameter of the tumors ranged from 2.8 to 3.8 cm (average, 3.1 cm). Histological examinations showed massive hemorrhage and increased vascularity, with dilated, thin-walled vessels, in all cases. The size of the tumor and the increase in vascularity with dilated, thin-walled vessels within neurinomas are important pathogenetic factors of hemorrhage. When sudden onset of symptoms or rapid worsening of chronic symptoms occurs in neurinomas, intratumoral or subarachnoid hemorrhage should be considered as a possible cause, and magnetic resonance imaging can be an important tool in obtaining correct diagnosis.

Adult↗

PubMed1992

Ruptured aneurysm arising from the anomalous anterior cerebral artery--case report.

A 64-year-old male presenting with subarachnoid hemorrhage had a saccular aneurysm arising from the anomalous anterior cerebral artery. The aneurysm was located on the curved mid-portion of the anomalous artery and extended underneath the right optic nerve. The aneurysm was clipped without unroofing the right optic canal. Postoperatively, he suffered from temporary mild deterioration of the right visual acuity. Hemodynamic stress may be important in the development of such aneurysms.

Aneurysm, Ruptured↗

PubMed1992

[Cool storage of fetal rat brain for neural transplantation].

The availability, storage and transportation of donor tissue are major practical problems associated with the potential use of grafted neural cell replacements in neurodegenerative diseases. The capacity to collect and maintain viable fetal neural tissue would facilitate possible clinical applications, and provide opportunities to study various neural diseases. In the present study, we examined the effect of cool storage on the survivability of intraventricular rat fetal ventral mesencephalic grafts (gestational days 15). In all experiments, fetal ventral mesencephalons were dissected out under a dissecting microscope in calcium-free magnesium-free buffer (CMF: 0.15 M NaCl, 0.008 M Na2HPO4, 0.0027 M KCl, 0.0015 M KHPO4, 0.026 M NaHCO3, with 0.1% glucose, 100 micrograms/ml streptomycin, 2.5 micrograms/ml fungizone). Fetal mesencephalic tissue was grafted into the lateral ventricle following pregraft refrigeration in calcium-free magnesium-free buffer at 4 degrees C. Fetal mesencephalic tissue was hibernated for 5, 12, 16, 20, 24, 28, 32 hours (group A, B, C, D, E, F and G, respectively). As a control group, fetal mesencephalic tissue was grafted into the lateral ventricle immediately after dissection. Grafted fetal mesencephalic tissue which had been hibernated for 16 hours or less survived well. There were no significant decreases in the size of grafts among group A, B, C and the control group. In group A, B, C and the control group, clusters of TH-positive neurons and dense networks of neuritic profiles within the grafts provided a morphological appearance reminiscent of the dendritic bundles that characterize the zone reticulate of the substantia nigra in situ.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

[Infection of methicillin resistant Staphylococcus aureus (MRSA) in patients with cardiovascular operations: four years' clinical analysis of the effect of strategy of prophylactic and treatment].

To evaluate the effect of strategy to reduce the rate and outcome of MRSA infection, 940 patients with cardiovascular operations from 1988 to 1991 were analyzed in aspect of the infection rate and outcome per year. Prophylactics and treatments which have been done during recent four years were) to use the inhalation of vancomycin for MRSA carriers, to quit the intravenous administration of prophylactic antibiotics on third postoperative day, to limit medical staffs to treat the patient with MRSA infection, to choose the most susceptible combination of two antibiotics for MRSA in each patients by periodical checking of bacterial cultures. The percentages of patients with infection to all patients detected with MRSA per year were decreased from 80% in 1988, to 66% in 1989, 31% in 1990, and 30% in 1991. The numbers of patients who died from MRSA infection were 4 in 1988 and only one in 1989 and 1991. MRSA infection in cardiovascular surgery could be reduced by sophisticated methods of prophylactics and treatments.

Anti-Bacterial Agents↗

PubMed1992

[Unbranched-site aneurysm of intracranial internal carotid artery].

Most intracranial saccular aneurysms arise from the angle between a parent vessel and an arterial branch. Saccular aneurysms without relation to any arterial branch are rare. During the last 24 years, 210 patients with intracranial internal carotid artery (ICA) aneurysms were directly operated on at our institution. We found eight saccular aneurysms arising from intracranial ICA without relation to any arterial branch. So we call them unbranched-site aneurysms of intracranial ICA, and describe their unique characteristics. Of the eight cases with unbranched-site aneurysm of intracranial ICA, three were men and five were women. The age ranged from 31 to 61 years with an average age of 48. Seven cases suffered a subarachnoid hemorrhage due to ruptured unbranched-site aneurysm, and the other case had been admitted to our department because of accompanying ruptured left internal carotid-posterior communicating aneurysm. All cases of unbranched-site aneurysm presented intraoperative and/or angiographic findings of arteriosclerosis, and five of the patients had a past history of hypertension. Of the four unbranched-site aneurysms at the C2 portion of ICA, two arose from the lateral wall, one arose from the superior wall and the other arose from the infero-lateral wall of ICA. Of the four unbranched-site aneurysms at the C1 portion of ICA, three arose from the superior wall and the other arose from the supero-medial wall of ICA. Radical operation was performed in all cases and intraoperative rupture occurred in two cases. It was suggested that arteriosclerotic change in the arterial wall, and local hemodynamic stress played important roles in the development of unbranched-site aneurysms of intracranial ICA.

Adult↗

PubMed1992

New enzymatic method with tryptophanase for determining potassium in serum.

We established a simple and rapid enzymatic method for measuring potassium ion in serum by using tryptophanase (EC 4.1.99.1) purified from Escherichia coli K12 strain (E. coli K12 IFO 3301). The presence of pyridoxal 5-phosphate promotes this enzymatic reaction, and potassium and (or) ammonium ions further accelerate it, with ammonium and potassium ions providing equivalent acceleration. We eliminated endogenous ammonium ion by using glutamate dehydrogenase (GLDH; EC 1.4.1.4), then produced ammonium ion in the presence of tryptophanase, tryptophan, and pyridoxal 5-phosphate. The concentration of formed ammonium ion, which was proportional to that of potassium ion in sample, was determined by adding GLDH to produce NADP+ in the presence of 2-oxoglutarate and NADPH; we then read the change of absorbance at 340 nm. The standard curve was linear for potassium ion concentrations up to 7.00 mmol/L. The within-assay variation (CV) was 0.89% at 5.51 mmol/L and 1.32% at 3.37 mmol/L. The day-to-day CVs were 0.99% at 6.85 mmol/L and 1.71% at 3.52 mmol/L. Analytical recoveries ranged from 98.7% to 108.9%. The correlation coefficient between values obtained with this enzymatic assay (y) and by flame photometry (x) was 0.995: y = 0.984x + 0.091 mmol/L (Sy.x = 0.105, n = 100). The presence of hemoglobin, bilirubin, or other cations little affects this system.

Ammonia↗

PubMed1991

The effect of a new immunosuppressive agent, FK-506, on xenogeneic neural transplantation in rodents.

This study examines the effect of a novel immunosuppressive agent FK-506 (FK) on the survivability of embryonic (E14) rat ventral mesencephalic tissue after intracerebral grafting to the lateral ventricle of adult mice. The recipient mice were given FK in doses of 10 mg/kg or 1 mg/kg for 2 weeks postgrafting, at which time they were sacrificed and histologically processed except for one group of animals on the high dose (10 mg/kg). In this group most animals died from side effects of the drug during the following days. Only the mice receiving the high dose of FK displayed healthy grafts without signs of rejection.

Animals↗

PubMed1991

Adventitial red blood cells produce intimal platelet accumulation in cerebral arteries of cats following subarachnoid hemorrhage.

After dividing 21 cats into three equal groups, we exposed their right middle cerebral arteries transorbitally and adventitially irrigated them with 2 ml washed red blood cells, blood plasma, or saline. To determine arterial intimal platelet accumulation in each cat, we injected [111In]oxine-labeled platelets intravenously immediately before injecting the various experimental solutions. Animals were sacrificed 2 or 4 hours following the injection of labeled platelets. Irrigation with washed red blood cells produced a significantly greater intraluminal accumulation of platelets than irrigation with saline (p less than 0.05). Plasma tended to have less of an effect on platelet accumulation than washed red blood cells, but this difference was not significant. These data suggest that the adventitial blood fraction responsible for intimal platelet accumulation in cerebral arteries following subarachnoid hemorrhage may be derived mainly from the red blood cell fraction.

Animals↗

PubMed1991

Hemifacial spasm due to cerebellopontine angle epidermoid tumor--case report.

The authors report a case of cerebellopontine angle epidermoid presenting as typical hemifacial spasm. A 33-year-old male had experienced intermittent right hemifacial spasm for 2 years. Cranial nerve examination was otherwise normal, including auditory and trigeminal nerve functions. Metrizamide computed tomographic cisternography and magnetic resonance imaging demonstrated a characteristic epidermoid tumor. The tumor was totally removed. Postoperatively, no facial spasm or other facial nerve dysfunction was noted.

Adult↗

PubMed1991

Hemifacial spasm caused by a spontaneous dissecting aneurysm of the vertebral artery. Case report.

The authors describe the first reported case of dissecting aneurysm presenting with hemifacial spasm. The patient was a 58-year-old woman with left hemifacial spasm of 2 years' duration. Cranial nerve examination was otherwise normal and no other clinical symptoms were observed. Vertebral angiography revealed a fusiform enlargement of the left vertebral artery and contrast medium remaining in the intramural false lumen in the venous phase. Microvascular decompression of the facial nerve with wrapping of the aneurysm resulted in complete relief of the hemifacial spasm.

Aortic Dissection↗

PubMed1991

[The effect of a new immunosuppressive agent, FK-506, on xenogeneic neural transplantation in rodents--comparison with cyclosporin A].

The present study was performed to compare the immunosuppressive effect of FK-506 (FK) with cyclosporin A (CyA) in xenogeneic neural transplantation in rodents. The solid grafts of embryonic ventral mesencephalic tissue from 14-day rat embryos were transplanted into the right lateral ventricle of 20 mature male mice using a stereotactic approach, and the mice were sacrificed 14 days after transplantation. The removed brains, which were sectioned coronally, were stained with antibodies against glial fibrillary acidic protein (GFAP), Lyt-2 or tyrosine hydroxylase (TH) in addition to hematoxylin-eosin and Nissl stainings. The subcutaneous (s.c.) administration of FK at a dose of 10.0 mg/kg daily for 14 days enabled the neural xenografts to survive and grow (n = 5), although all of the neural xenografts treated with CyA at a dose of 10.0 mg/kg s.c. (n = 5) or FK at a dose of 1.0 mg/kg s.c. (n = 5) daily for 14 days and ones treated without such an immunosuppressive agent (n = 5) were rejected by immunological reactions. We conclude that FK is a more powerful immunosuppressive agent than CyA in xenogeneic neural transplantation as well as in cardiac and renal allograftings.

Animals↗

PubMed1991

[The effect of chronic treatment of deprenyl in animal models of Parkinson's disease].

Recent studies have demonstrated that deprenyl can delay the progression of parkinsonian syndrome. Deprenyl selectively and irreversibly inhibits the activity of monoamine oxidase-type B (MAO-B), and subsequent enzyme activity requires de novo synthesis of MAO-B. In this study we investigated (1); the effects of deprenyl on striatal dopamine (DA) levels in MPTP-lesioned and undamaged mice and (2); the effect of deprenyl on L-DOPA induced rotational movements in a hemiparkinsonian model monkey. In MPTP-lesioned mice, deprenyl increased the striatal DA levels by 123%, 78% immediately and one week after termination of deprenyl treatment respectively, while by 31%, 24% in MPTP-undamaged mice, respectively. Four weeks after termination of treatment, and the striatal DA was not significant. It shows that deprenyl is effective in elevation of striatal DA at least one week after termination of treatment, and the degree of increase of striatal DA following deprenyl treatment is greater in MPTP-treated mice than in undamaged mice. Deprenyl seemed to be effective longer in a hemiparkinsonian monkey than in rodents. The result suggests that less frequent administration of deprenyl may be effective in controlling side effects of L-DOPA without reducing therapeutic efficacy.

Animals↗

PubMed1991

[Cografting technique in the treatment of Parkinson's disease].

Intracerebral grafting of dopamine containing adrenal chromaffin cells to the brain of experimental animals can ameliorate the symptoms of experimentally induced Parkinson's disease. Clinical trials of adrenal autograft to the patients with Parkinson's disease are on-going with variable results and autopsy cases show poor survivability of grafted chromaffin cells. The present study was performed to determine if transected peripheral nerve could provide sufficient nerve growth factor to enhance the survivability of grafted chromaffin cells. Survivability of grafted chromaffin cells increased when cografts with sciatic nerve were performed, and host dopaminergic fiber recovery was more prominent in mice with cografts than in mice with adrenal grafts alone. Although this enhanced survivability and recovery of host fibers were seen in cografted mice from aging donors, the degree of these effects was greater in cografted mice from young donors. Considering these results, we suggest that methods to increase the survivability of grafted chromaffin cells be explored more deeply because such survivability might be closely related to the functional recovery of patients with Parkinson's disease, using this grafting procedure.

Adrenal Medulla↗

PubMed1991

[Cografts of adrenal medulla and peripheral nerve in a mouse model of Parkinson's disease].

Systemic injection of MPTP damages the nigrostriatal dopaminergic system in C57B1/6 mice. Since transected peripheral nerve segments are known to produce nerve growth factor, we performed adrenal medullary grafts or cografts of adrenal medulla and sciatic nerve into the striatum of MPTP-treated mice, and compared the survivability of grafted chromaffin cells and the recovery of intrinsic host dopaminergic fibers. Survivability of grafted chromaffin cells increased when cografts with sciatic nerve were made, and host dopaminergic fiber recovery was more prominent in mice with cografts than in mice with adrenal grafts alone. The degree of recovery of host intrinsic dopaminergic fibers was greater in younger host striatum than in older host striatum. We conclude that cografts of adrenal medulla and sciatic nerve increase the survivability of grafted chromaffin cells better than adrenal medullary grafts alone, and that survivability of grafted chromaffin cells promotes host dopaminergic fiber recovery.

Adrenal Medulla↗

PubMed1990

Central neurocytoma--case report.

The authors present a case of central neurocytoma in a 34-year-old female who had experienced intermittent headaches over a 10-year period. On computed tomographic (CT) scans and magnetic resonance images, the tumor appeared as a large, calcified mass occupying both lateral ventricles. A right parieto-occipital craniotomy was performed and the tumor was totally removed. While the light microscopic findings suggested a diagnosis of oligodendroglioma, electron microscopic examination demonstrated clear vesicles, microtubules, and synaptic structures within the abundant cytoplasmic processes of the tumor cells. Immunohistochemical examination showed the tumor cells to be strongly positive for neuron-specific enolase, sparsely positive for S-100 protein, and negative for glial fibrillary acidic protein. The final histological diagnosis was central neurocytoma. The postoperative course was uneventful and no further treatment was administered. She has no neurological deficits and CT has shown no evidence of recurrence during the 2 years since her surgery. Central neurocytoma is a rare tumor arising in the lateral ventricle, and the diagnosis is mainly based on electron microscopic findings. Since central neurocytoma appears to have a good prognosis following total removal alone, it is very important to distinguish between this and other ventricular tumors.

Adult↗

PubMed1990

[Recovery of nigrostriatal and mesolimbic dopaminergic system following administration of ganglioside in MPTP-treated mice].

The effects of systemic injection of GM 1 ganglioside on dopaminergic (DA) nigrostriatal and mesolimbic system following 1-methyl-4-phenyl-1, 2,3,6-tetrahydropyridine (MPTP) have been studied in C 57 BL/6 mice. MPTP treatment (4 x 20 mg/kg i.p. given 12 hr apart) resulted in significant depletion of DA concentration in the major terminal fields of the nigrostriatal and mesolimbic DA systems, i.e. dorsal striatum, ventral striatum, nucleus accumbens and olfactory tubercle 5 weeks after treatment in young (2 month old) mice. In aging (12 month old) mice treated with MPTP, significant depletion of DA concentration was observed in the cell body regions, i.e. substantia nigra and ventral tegmental area in addition to the major terminal fields, suggesting that the effect of MPTP is more widespread in aging mice. Although GM 1 ganglioside treatment (30 mg/kg, i.p. daily for 5 weeks) partially restored DA concentration in every major terminal field in young mice, such an apparent recovery was not seen in aging mice. GM 1 ganglioside treatment also reduced the increased 3,4-dihydroxyphenylacetic acid (DOPAC)/DA ratio following MPTP injection in the striatum of young mice, but such an effect was not observed in aging mice. We conclude that DA nigrostriatal and mesolimbic system in aging mice demonstrates reduced regenerative capacity following MPTP depletion compared with young mice, and the beneficial effect of GM 1 ganglioside for the recovery of DA nigrostriatal and mesolimbic system neurons declines with age.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗