Biomedical subjects

Kiyoshi Ishii

Publications and source records attributed to Kiyoshi Ishii.

At least 19 recordsLinked to original sources

PubMed2006

Fungi can be a useful forensic tool.

We present a practical case in which the fungi have contributed to the estimation of postmortem interval of the cadaver. A 71-year-old man wearing a shirt and pants was found dead at the bottom of an open well about 6m below the ground in his garden. Externally the face was dotted with colonies of white fungi, which was devoid of dipteran larvae and other insects. The fungi were identified as Penicillium sp. and Aspergillus terrous. These fungi, widely inhabit in the life circumstances, can generally colonize 3-7 days after attaching on the subjects. The appearance of the body surface, the state of decomposition of various organs, police information describing that the man had last been seen 12 days before discovery and the fungal evidence indicated that the man had been dead for about 10 days. We suggest that fungi can provide an useful means of estimating the minimum interval since death when forensic entomology is not applicable. Although, no data about growth rates of the fungi on human cadavers have been available, further researches should be needed to clarify the successive colonization of fungi on human cadavers.

Aged↗

PubMed2006

Reduction of instrumental discrimination performance by post-conditioning devaluation of discriminative stimulus: the effects of novelty in reinforcing outcome and extended training.

In three experiments the effects of post-conditioning pairings of a discriminative stimulus (Sd) with an illness-inducing agent (lithium chloride, LiCl) on subsequent discrimination performance in extinction and consumption of reinforcing outcome were investigated. Rats were trained to choose a correct lever to obtain food pellets, with a light presented on a bulb just above the correct lever serving for the Sd on each trial. After achievement of a criterion of the discrimination, animals received paired or unpaired presentations of the Sds and LiCl injection. In Experiment 1, in which a familiar outcome was given throughout the discrimination training, Sd-LiCl pairings did not reduce either lever-press performance during presentation of the Sds or amount of consumption of outcomes. On the other hand, in Experiment 2 where a novel outcome was introduced in the final two sessions of the discrimination training, subsequent Sd devaluation reduced lever-press performance during presentations of the Sds. Similar findings were obtained in Experiment 3, in which animals were given extended discrimination training with introduction of novel outcomes in the final two sessions. These findings suggest that a representation of the outcome, evoked by presentation of the Sd, and illness were associated in the course of Sd-LiCl pairings but only when a novel outcome was used.

Animals↗

PubMed2006

Analysis of fungi detected in human cadavers.

We examined and identified fungi flora found growing on two human cadavers. The main isolate colonized on the surfaces of the skin and bones was morphologically identified as Eurotium repens. The genus Eurotium usually inhabits soil and exhibits osmophilic properties. Because the cadavers contained abundant organic materials, Eurotium species formed ascomata and conidia. To our knowledge, this is the first study to describe in detail the species of fungus obtained from human cadavers. Because the detection of some species of fungus found in human cadavers may reveal the local habits of them, more forensic cases is needed to develop fungi into the forensic tool.

Aged↗

PubMed2005

[Improvement in visibility and detectability of early sign of acute stroke in nonenhanced CT images by using an adaptive partial smoothing filter].

Detection of early infarct signs on nonenhanced CT is mandatory in patients with acute ischemic stroke. Loss of the gray-white matter interface at the lentiform nucleus or the insular ribbon has been an important early infarct sign, which affects decisions on thrombolytic therapy. However, its detection is difficult, since early infarct sign is of subtle hypoattenuation. To improve the detectability of early infarct sign, image processing that could reduce local noise while preserving edges is desirable. To examine this issue, we devised an adaptive partial smoothing filter (APSF). Since the APSF markedly improves visibility of the normal gray-white matter interface, loss of the gray-white matter interface due to hypoattenuation could be more easily detected. The APSF was applied to clinical CT images in hyperacute stroke patients. Our preliminary results showed that the visibility and detectability of early infarct signs was much improved. To validate the usefulness of the proposed method, two commonly used smoothing filters were also employed for comparison. The results demonstrated the superiority of the APSF. Our proposed APSF can improve the visibility of the gray-white matter interface, thereby enhancing the detectability of early infarct signs.

Acute Disease↗

PubMed2005

Thrombosed vertebral artery aneurysm presenting with hemorrhage and bulbar compression: report of two cases.

Bulbar compression by vertebral artery (VA) aneurysm is extremely rare and only reported in a few cases. We report two cases with thrombosed VA aneurysm compressing medulla oblongata; one presented with bulbar apoplexy hemorrhage and the other with subarachnoid hemorrhage (SAH). A 61-year-old male (case 1) presented with consciousness disturbances, left hemiplegia, and subsequent respiratory arrest. He was subjected to controlled ventilation, and computed tomography (CT) scan showed bulbar hemorrhage. Magnetic resonance imaging (MRI) and digital subtraction angiogram (DSA) revealed fusiform right VA aneurysm with partial thrombosis and bulbar compression. Intra-aneurysmal embolization with Guglielmi detachable coils (GDCs) relieved his clinical symptom including respiratory disturbance. Three months after the onset, he remained moderately disabled. A 76-year-old male (case 2) presented with severe headache and subsequent respiratory disturbance. CT scan on admission showed subarachnoid hemorrhage with acute hydrocephalus. Ventricular drainage rapidly improved consciousness while respiratory disturbance persisted over several days. MRI and DSA suggested spontaneous thrombosis of the right VA dissection with bulbar compression. He showed gradual recovery of his respiration over a week. After ventriculo-peritoneal shunting, he was transferred with moderate disability. These results suggest that the elimination of the pulsatile effect of VA aneurysm adjacent to medulla oblongata can improve symptoms caused by aneurysm-related compression. Early diagnosis and appropriate treatment such as intra-aneurysmal embolization for ameliorating the blood flow inside the aneurysm can relieve mass effect and clinical symptoms.

Aged↗

PubMed2004

Cerebral infarction in the caudate nucleus associated with acute epidural hematoma and diffuse brain injury in a child after severe head injury.

CASE REPORT: A 6-year-old boy was admitted to our hospital 20 min after receiving a direct impact to his head in an automobile accident. He was semi-comatose on admission and computed tomography showed acute epidural hematoma in the right supratentorial region. Three hours later, his consciousness deteriorated due to the enlargement of the hematoma. Surgical removal of hematoma relieved his consciousness disturbance. Post-operative magnetic resonance imaging revealed spotty high-intensity lesions in the corpus callosum on T2-weighted images, and a solitary high-intensity lesion in the left caudate nucleus extending to the medial globus pallidum on T2-weighted and diffusion-weighted images. Magnetic resonance angiography showed no abnormality in the main arteries. These results suggested cerebral infarction in the vascular territory supplied by the recurrent artery of Heubner in association with diffuse brain injury. Post-operative course was uneventful and he was discharged without neurological deficit. CONCLUSIONS: Post-traumatic cerebral infarction in the caudate nucleus is extremely rare, and its association with diffuse brain injury and epidural hematoma is apparently unique.

Brain Injuries↗

PubMed2004

Hydrocephalus due to cerebrospinal fluid overproduction by bilateral choroid plexus papillomas.

CASE REPORT: A 10-month-old boy, with congenital deafness and blindness associated with chromosomal deletion [46XY, del(13)(q32)], presented with intractable ascites 9 months after ventriculo-peritoneal shunting for congenital hydrocephalus. Revision of the ventriculo-atrial shunt resulted in shunt failure 1 month later. External ventricular drainage revealed cerebrospinal fluid (CSF) overproduction (2,000 ml/day). Magnetic resonance imaging showed marked lobular enlargement of the bilateral choroid plexuses extending from the trigone to the body and inferior horn of the lateral ventricle. Multi-staged resection was performed via bilateral temporo-occipital transcortical approaches, and CSF production significantly decreased to 100 ml/day postoperatively. Histological assessment of the villous surface suggested villous hyperplasia of the choroid plexus and thorough evaluation including the proximal portion of the lobular lesion near the attachment revealed choroid plexus papilloma. He was discharged after ventriculo-peritoneal shunting without additional neurological deficits except for hyperreflexia of the left extremities. CONCLUSION: CSF overproduction caused by bilateral choroid plexus papillomas can result in hydrocephalus. Radical resection of the bilateral ventricular lesions should be considered for this entity. Thorough evaluation of the surgical specimen is recommended because histological examination of only the lobular surface of the choroid plexus lesion may fail to identify choroid plexus neoplasm.

Cerebrospinal Fluid↗

PubMed2004

A distal anterior cerebral artery aneurysm in infant: disappearance and reappearance of the aneurysm.

The incidence of intracranial aneurysms in childhood is rare, especially in infancy. Spontaneous thrombosis of a cerebral aneurysm in a child is very rare, particularly in a non-giant aneurysm. We report a case of a 1-month-old girl with a distal anterior cerebral artery aneurysm which disappeared spontaneously after subarachnoid hemorrhage and reappeared 6 months later. Surgical resection of the aneurysm was performed and she discharged uneventfully 10 days later. Histological examination revealed an aneurysm with a fibrous muscular layer, absence of the internal elastic lamina and partial hypertrophy of the intimal layer. Though the pathogenesis of this aneurysm is uncertain, two hypotheses are discussed.

Cerebral Arteries↗

PubMed2004

Topical administration of iganidipine, a new water-soluble Ca2+ antagonist, increases ipsilateral optic nerve head circulation in rabbits and cynomolgus monkeys.

PURPOSE: To evaluate the effects of topically administered iganidipine hydrochloride, a novel water-soluble Ca2+- channel blocker, on optic nerve head (ONH) circulation in Dutch rabbits and cynomolgus monkeys. METHODS: ONH tissue blood velocity (NBONH) was determined using the laser speckle method. In rabbits, NBONH was measured for 90 minutes before and after a single iganidipine administration, or before and after twice-daily ad- ministrations for 21 days (0.03%). In monkeys, NBONH was measured before and after twice-daily administrations of iganidipine for 7 days (0.03 or 0.1%). RESULTS: Iganidipine (0.03% solution) significantly increased NBONH by 8 to 10% in treated eyes after a single administration (p < 0.05) or by 18 to 35% after 7-, 14-, or 21-day twice-daily administration in rabbits (p < 0.05). In monkeys, 0.03% and 0.1% iganidipine significantly increased NBONH in treated eyes by 20 and 41% after 7-day (p < 0.05) twice-daily administration, respectively. CONCLUSION: Topical iganidipine significantly increased ONH blood velocity in treated eyes.

Administration, Topical↗

PubMed2004

Effects of topically instilled bunazosin, an alpha1-adrenoceptor antagonist, on constrictions induced by phenylephrine and ET-1 in rabbit retinal arteries.

PURPOSE: To examine the inhibitory effects of topically instilled bunazosin hydrochloride (bunazosin), a selective alpha1-adrenoceptor antagonist, on the retinal artery constrictions induced by intravitreous phenylephrine hydrochloride (phenylephrine) and endothelin (ET)-1 in rabbits. METHODS: Phenylephrine or ET-1 (20 microL) was injected into the central part of the vitreous in both eyes in pigmented rabbits. Color fundus photographs were taken at 5 minutes before and 60 minutes after the injection. The average diameter of the major retinal arteries at the rim of the optic nerve head (ONH) was normalized with respect to ONH diameter. Bunazosin was instilled into one eye (chosen randomly) and vehicle into the fellow eye at 60 minutes before the intravitreous injection. To examine any interaction between the alpha1-adrenoceptor and ET receptor, phenylephrine and ET-1 were co-injected at individually ineffective doses. In addition, ET-1-induced vasoconstriction was examined after unilateral superior cervical ganglionectomy. The binding affinities of bunazosin for ETA and ETB receptors were also evaluated. The series of experiments was performed as masked tests. RESULTS: Retinal arteries were dose-dependently constricted by both intravitreous phenylephrine and intravitreous ET-1. Topically instilled bunazosin at 0.01% partly inhibited both of these vasoconstrictions on the ipsilateral side, but not on the contralateral side. Bunazosin did not bind to ET receptors. Co-injection of phenylephrine and ET-1 at individually ineffective doses constricted retinal arteries significantly. An adrenergic supersensitivity in retinal arteries was observed after superior cervical ganglionectomy only on the ganglionectomized eye. The ET-1-induced vasoconstriction was significantly weaker in cervical ganglionectomized eyes than in sham-surgery eyes. CONCLUSIONS: The present findings suggest that topically instilled bunazosin reaches the posterior retina by local penetration at concentrations sufficient to attenuate the phenylephrine- or ET-1-induced constriction of retinal arteries in normal rabbit eyes, and that the inhibitory effect of bunazosin on the ET-1-induced vasoconstriction in this tissue may be partly attributable to an interaction between the alpha1-adrenoceptor and ET receptor.

Administration, Topical↗

PubMed2003

Antigenicity of porcine cornea as xenograft.

PURPOSE: To investigate the antigenicity of porcine corneal stroma as xenograft to man. METHODS: The localization of alpha-gal epitope in the porcine eye was determined using biotinylated Griffonia simplicifolia 1 isolectin B4. Porcine corneal stromal was inserted into corneal stromal pockets of cynomolgus monkeys. Immunohistochemistry was performed to analyze the immunological reaction in the monkey. RESULTS: Immunohistochemistry showed no alpha-gal epitope in the porcine cornea except for several keratocytes in the anterior-most part. Haze and keratic precipitates developed in two corneas out of three corneas that were followed up until 6 months after the surgery. In these two corneas, infiltrating cells included CD4+, CD8+, or HAM56+ cells, suggesting that haze and keratic precipitates were induced by cellular rejection to porcine corneal stroma. CONCLUSIONS: Porcine corneal stroma induces no hyperacute rejection but mild cellular rejection when transplanted in the cornea of cynomolgus monkeys.

Animals↗

PubMed2003

Iganidipine, a new water-soluble Ca2+ antagonist: ocular and periocular penetration after instillation.

PURPOSE: To evaluate the potential of topical iganidipine ophthalmic solution to exert Ca(2+)-antagonistic activity in the posterior parts of the eye without inducing systemic effects, ocular and periocular penetration of topically instilled iganidipine was studied in pigmented rabbits. METHOD: First, (14)C-iganidipine solution (0.03%, 30 microL) was instilled into one eye, and vehicle into the other eye to determine the intraocular penetration of iganidipine and to measure the radioactivity of ocular tissues 0.25, 0.5, 1, 2, 4, and 12 hours after a single instillation (n = 3, respectively). Second, iganidipine (0.03%) or betaxolol (0.5%) was unilaterally instilled twice daily for 20 days to study the effects on intravitreously injected various doses of endothelin (ET)-1-induced retinal artery constriction to evaluate whether a pharmacologically active level of the drug penetrated to the posterior retina and to estimate the drug level in the posterior retina (n = 6, respectively). Third, iganidipine (0, 10, or 30 microg/kg: n = 6, 3, and 6, respectively) was intravenously injected to study the effects on intravitreously injected ET-1-induced retinal artery constriction to evaluate iganidipine levels in the posterior retina. Fourth, periocular penetration of iganidipine was studied by means of whole-head autoradiography after a single instillation of (14)C-iganidipine (0.09%, 30 microL; n = 5). RESULTS: Penetration of topically applied iganidipine to the cornea or aqueous humor was high and estimated to be at least 10 times higher than that reported for timolol or carteolol. Concentrations in the iris-ciliary body or retina-choroid were much higher than in the plasma, both in the treated and control eyes, suggesting that iganidipine binds to uveal pigments. Twice-daily 20-day instillation of iganidipine (0.03%), but not of betaxolol (0.5%), significantly suppressed constriction of the retinal arteries induced by intravitreous injection of ET-1 at a dose of 2.5 or 0.5 ng in the ipsilateral eye. Intravenous injection of iganidipine at a dose of 30 microg/kg (giving a free plasma concentration of approximately 10(-8) M), but not at a dose of 10 microg/kg, significantly suppressed intravitreous ET-1-induced (0.5 ng) constriction of the retinal artery to a similar degree as twice-daily 20-day instillation of 0.03% iganidipine. After a single instillation of 0.09% iganidipine, the equivalent concentration of iganidipine in the ipsilateral retrobulbar periocular space estimated from autoradiography was approximately 3.9 x 10(-8) M between 15 minutes and 1 hour after instillation, consistently higher than in the untreated contralateral eyes by approximately 3.0 x 10(-8) M (P = 0.043). CONCLUSIONS: In rabbits, topically instilled iganidipine, a Ca(2+) antagonist, in a 0.03% solution reaches the ipsilateral posterior retina or retrobulbar periocular space by local penetration at concentrations sufficient to act as a Ca(2+) antagonist.

Administration, Topical↗

PubMed2003

Time course of the change in optic nerve head circulation after an acute increase in intraocular pressure.

PURPOSE: To investigate the time course of changes in optic nerve head (ONH) circulation after an acute increase in intraocular pressure (IOP), by using the laser speckle method, and to evaluate the effects of a calcium antagonist, the nitric oxide synthetase inhibitor, indomethacin, or sympathetic nerve amputation on the response in ONH circulation after an acute increase in IOP. METHODS: In rabbits, the normalized blur (NB) level, a quantitative index of tissue blood velocity in the ONH, was monitored for 60 minutes after an increase in IOP from 20 mm Hg to 40, 50, or 60 mm Hg and for 25 seconds after increase in IOP from 20 mm Hg to 50 or 60 mm Hg with high time resolution. The effects of systemic administration of 1 micro g/kg per hour nilvadipine (a calcium antagonist), 30 mg/kg N(omega)-nitro-L-arginine (L-NAME), or 5 mg/kg indomethacin, or those of sympathetic nerve amputation on the time course of the changes in NB were studied. RESULTS: NB showed a quick recovery within several seconds after increase in IOP to 40 or 50 mm Hg, whereas no or little recovery occurred after an increase to 60 mm Hg. The nilvadipine treatment significantly increased NB at IOP of 20 mm Hg (baseline NB, P = 0.045) and apparently impaired the recovery of NB after the increase in IOP. After L-NAME administration, baseline NB significantly decreased (P = 0.028), and the NB recovery time was slightly but significantly prolonged (P = 0.012). Indomethacin showed no effects on baseline NB or NB recovery. Sympathetic nerve amputation increased baseline NB (P = 0.027), but did not influence NB recovery. CONCLUSIONS: The current results showed a quick recovery response in the ONH circulation after an acute increase in IOP in rabbits. A calcium antagonist impaired the response. Production of nitric oxide or prostaglandins or the sympathetic nervous system is probably not mainly responsible for the reaction.

Animals↗

PubMed2002

An infant chimpanzee (Pan troglodytes) follows human gaze.

The ability of non-human primates to follow the gaze of other individuals has recently received much attention in comparative cognition. The aim of the present study was to investigate the emergence of this ability in a chimpanzee infant. The infant was trained to look at one of two objects, which an experimenter indicated by one of four different cue conditions: (1) tapping on the target object with a finger; (2) pointing to the target object with a finger; (3) gazing at the target object with head orientation; or (4) glancing at the target object without head orientation. The subject was given food rewards independently of its responses under the first three conditions, so that its responses to the objects were not influenced by the rewards. The glancing condition was tested occasionally, without any reinforcement. By the age of 13 months, the subject showed reliable following responses to the object that was indicated by the various cues, including glancing alone. Furthermore, additional tests clearly showed that the subject's performance was controlled by the "social" properties of the experimenter-given cues but not by the non-social, local-enhancing peripheral properties.

Animals↗

PubMed2002

Symptom changes caused by movement of a calcified lateral ventricular meningioma: case report.

BACKGROUND: Large calcified psammomatous meningioma in the left lateral ventricle with a long silent interval of 16 years was presented. The symptoms varied by its moving not enlargement, which was described by sequential images of the brain computer tomography. Combined approaches of transcallosal and transinferior temporal sulcus routes were superior to prevent injury of the speech center in the dominant hemisphere.

Adult↗

PubMed2002

Unruptured carotid-duplicated middle cerebral artery aneurysm: case report.

We demonstrate the first case with unruptured carotid-duplicated middle cerebral artery (IC-Dup MCA) aneurysm combined with ruptured opposite carotid aneurysm. Eleven IC-Dup MCA aneurysm reported until now had all ruptured. It is noteworthy that 8 patients of the 11 were Japanese.

Angiography, Digital Subtraction↗

PubMedDate not supplied

Effects of topical phenylephrine on blood flow in the posterior segments of monkey and aged human eyes.

PURPOSE: The aim of this study was to evaluate the effects of topical 5% phenylephrine on circulation in the optic nerve head (ONH) of cynomolgus monkeys and in the central retinal artery (CRA) of aged patients. METHODS: In five monkeys, ONH tissue blood velocity (NB(ONH)), determined using the laser speckle method, and intraocular pressure (IOP), blood pressure (BP), and pulse rate (PR) were measured 2 h after a single unilateral instillation and after a 7-day twice-daily unilateral instillation of phenylephrine. In 20 aged patients (mean age: 70.4 years), the CRA circulation indices were determined by color Doppler imaging (CDI), and IOP, BP, and PR were measured before and after four serial unilateral instillations at 30-min intervals of phenylephrine. RESULTS: In the monkeys, there was no significant change in IOP, BR, or PR, while NB(ONH) decreased 2 h after a single instillation ( P = 0.080) and after a 7-day instillation ( P = 0.043). In theaged patients, IOP in the phenylephrine-treated eyes significantly increased ( P = 0.022), while the CDI indices, BR, and PR did not. In this CDI assessment, the statistical power to detect significant changes (P < 0.05) in the resistive index was estimated as 4.8% of the standard deviation. CONCLUSIONS: Topical phenylephrine decreased the ONH tissue blood velocity in monkeys, suggesting possible risks regarding circulation in the posterior portion of the eye. However, these effects were not observed in the CRA circulation in the patients.

Administration, Topical↗

PubMedDate not supplied

Effects of topically instilled bunazosin hydrochloride and other ocular hypotensive drugs on endothelin-1-induced constriction in rabbit retinal arteries.

PURPOSE: To compare the inhibitory effect of topically instilled bunazosin hydrochloride (bunazosin), a selective alpha(1)-adrenoceptor antagonist, on the endothelin (ET)-1-induced vasoconstriction in rabbit retinal arteries with the effects of other ocular hypotensive drugs. METHODS: ET-1 was injected into the central part of the vitreous of both eyes of pigmented rabbits. Color fundus photographs were taken 5 min before and 60 min after the injection. The average diameters of the two major retinal arteries at the rim of the optic nerve head (ONH) were normalized with respect to ONH diameter. Fifty microliters of 0.01% bunazosin, or 0.12% isopropyl unoprostone (unoprostone), 1% dorzolamide hydrochloride (dorzolamide), 0.25% nipradilol, 0.5% betaxolol hydrochloride (betaxolol), or 0.5% timolol maleate (timolol) was instilled into one eye of each rabbit 60 min before the ET-1 injection. The series of experiments was performed as masked tests. RESULTS: Bunazosin and unoprostone inhibited the ET-1-induced constriction of retinal arteries by 103% (P = 0.012 versus contralateral eyes) and 50% (P = 0.037), respectively. Dorzolamide, nipradilol, betaxolol, and timolol had no significant effects in this experiment. CONCLUSIONS: Under our experimental conditions, bunazosin and unoprostone inhibited the ET-1-induced constriction. Hence, bunazosin and unoprostone may be clinically more effective against ET-1-related retinal diseases.

Administration, Topical↗