Biomedical subjects

J Kawamura

Publications and source records attributed to J Kawamura.

At least 19 recordsLinked to original sources

PubMed1992

Possible model for generation of P9 far-field potentials.

The distribution of P9 far-field somatosensory evoked potentials, after stimulation of the median nerve with a knee reference, was examined to determine the mechanism of the generation of P9 potentials. In addition to positive potentials (P9s), we found a negative potential (N9) recorded from the chest ipsilateral to the stimulation. The simulation of the distribution of these P9/N9 potentials by an electrical circuit diagram suggested the validity of this model for generation of the P9s.

Electric Stimulation↗

PubMed1992

White matter lesions in the elderly.

The advent of neuroimaging has brought medical attention to the frequency of unsuspected white matter lesions in the brains of elderly people. In 1987 Hachinski suggested the term "leuko-araiosis" to identify such white matter abnormalities detected by computed tomography and magnetic resonance imaging to emphasize that their etiology and clinical relevance require clarification. Since then, leuko-araiosis has been recognized among approximately ten percent of apparently normal, elderly people over age sixty-five. The severity and frequency of leuko-araiosis increases with advancing age, risk factors for stroke, history of strokes particularly of the lacunar type and dementia of both the vascular and Alzheimer type. Current concepts concerning the pathogenesis and neurological concomitants of leuko-araiosis are reviewed. The etiology of leuko-araiosis may be heterogeneous but is most likely ischemic in nature. However, as white matter lesions progress among the elderly they are likely to become associated with cognitive impairments and motor dyspraxias presumably resulting from cortico-subcortical disconnections, particularly involving the frontal cortex and basal ganglia and may themselves be considered a radiological "risk factor" or precursor for dementia.

Aged↗

PubMed1992

Transient myoclonic state with asterixis in elderly patients: a new syndrome?

We report 7 patients who developed acute co-occurrences of fragmentary generalized myoclonus and asterixis. All patients were elderly and had other chronic diseases. This condition appeared acutely, progressed over several hours and then disappeared in 2-3 days with diazepam administration. No sequelae were noted, although most cases developed recurrences. The myoclonus occurred spontaneously and was slightly enhanced by action. The myoclonus was widely distributed but predominated in the neck, shoulder girdle, and upper extremities. Opsoclonus was not noted. Clinically apparent myoclonus was not evoked by sensory stimuli. Asterixis was observed in the upper extremities in all cases. Asterixis-like movements of the protruded tongue were also observed. Neurological findings other than the myoclonus and asterixis were unremarkable. Neither metabolic nor organic abnormalities clearly responsible for this condition were identified. Cerebral potentials preceding the myoclonic jerks recorded in one case suggested that the myoclonus may have been a spontaneous cortical myoclonus. We named this condition a transient myoclonic state with asterixis (TMA). Awareness of this syndrome is clinically important because of its benign nature, although it can recur.

Aged↗

PubMed1992

Leuko-araiosis and cerebral hypoperfusion compared in elderly normals and Alzheimer's dementia.

OBJECTIVE: To elucidate the pathogenesis of leuko-araiosis in patients with Alzheimer's disease by utilizing CT densitometry of the brain and measurements of local perfusion in order to quantify the extent of leuko-araiosis and local hypoperfusion compared with similar measurements made among age-matched normal volunteers. DESIGN: Cross-sectional case-control study. SETTING: Out-patient visits to a specialized laboratory located in a large hospital facility. PATIENTS: Eighteen elderly patients with probable dementia of Alzheimer type (DAT, aged 71.8 +/- 5.1 years) and 17 neurologically and cognitively normal, age-matched volunteers (aged 68.2 +/- 9.6 years) were admitted to the study according to established criteria. INTERVENTION: None MAIN OUTCOME MEASURES: Cerebral blood flow (mL/100 g brain/min) estimated by the xenon inhalation CT-CBF method correlated with volume percentage ratio (%) measured by CT densitometry for leuko-araiosis, compared to normal white and gray matter. RESULTS: Perfusion values for frontal and occipital white matter as well as frontal, parietal, temporal, and occipital cortex were all decreased in DAT patients. Ratios for leuko-araiosis to total brain tissue volumes were greater among patients with DAT compared with age-matched normal volunteers. White matter perfusion in zones of leuko-araiosis was decreased to a similar degree in both DAT and elderly normal volunteers. CONCLUSIONS: Perfusion is reduced to the same degree in regions of leuko-araiosis in elderly normals as in DAT patients, but the extent of leuko-araiosis is greater among DAT patients and presumably contributes to cognitive impairments.

Aged↗

PubMed1992

Patterns of cerebral hypoperfusion compared among demented and nondemented patients with stroke.

BACKGROUND AND PURPOSES: No reports are available that compare local cerebral perfusion among groups of patients suffering from multiple cerebral infarctions with and without cognitive impairments. The present study was designed to correlate changes in regional cerebral perfusion that may lead to dementia among patients with multiple cerebral infarctions by comparing measurements of local cerebral blood flow. METHODS: Local perfusion was measured using xenon-contrasted computed tomographic scanning among two groups of patients who had suffered from multiple cerebral infarctions: Group D (n = 12) were demented and had severe cognitive impairments, and group I (n = 11) were cognitively intact. Results were compared with similar measurements among neurologically and cognitively normal, age-matched volunteers (group N, n = 16). RESULTS: Mean local perfusion values were reduced among both groups with cerebral infarctions but to a more marked degree in group D (p less than 0.05). Perfusion of cerebral white matter was diffusely and severely reduced in group D (p less than 0.05) but was mildly reduced only in frontal and capsular white matter in group I (p less than 0.05). Perfusion of cerebral cortex was reduced in frontal (p less than 0.01) and temporal (p less than 0.01) regions among both groups but to a significantly greater degree in group D subjects (frontal, p less than 0.05; temporal, p less than 0.01), who also showed hypoperfusion of the occipital cortex (p less than 0.05), apparently because of underlying leukoaraiosis and cortical disconnections. Perfusion of the basal ganglia was reduced to the same degree among both groups of stroke patients (p less than 0.01). CONCLUSIONS: Leukoaraiosis with white matter hypoperfusion appears to be an important determinant for cognitive impairments among patients with multiple cerebral infarctions.

Aged↗

PubMed1992

[A case of a child with extra-adrenal pheochromocytoma associated with renovascular hypertension].

A 7-year-old female was discovered to be severely hypertensive. Urinary noradrenaline excretion and plasma noradrenaline level were elevated. Plasma renin activity was markedly elevated. She was found to have a mass in the hilus of the left kidney and left renal artery stenosis. Magnetic resonance imaging (MRI) of the mass revealed an extremely bright lesion on T2 weighted image. DMSA renal scintigraphy revealed a low uptake rate (4.7%) in the left kidney. A diagnosis of extra-adrenal pheochromocytoma associated with left sided renal artery stenosis was made. The mass and left kidney were removed. Electronmicroscopic examination of the mass revealed characteristic neurosecretory granules. There was only slight fibrosis in the wall of the removed left renal artery.

Child↗

PubMed1992

[Use of diltiazem in the anesthetic management of epinephrine predominant pheochromocytoma].

This report describes a case of epinephrine predominant pheochromocytoma successfully managed intraoperatively with an infusion of diltiazem. A 50-yr-old woman with a 10-yr history of diabetes mellitus was admitted to the hospital because of thirst and general fatigue. A cystic left adrenal tumor was found on computed tomographic scan. Although resting plasma catecholamine levels were normal, plasma norepinephrine and epinephrine levels obtained from the left adrenal vein were 1.6 ng.ml-1 (normal, 0.04-0.35) and 6.2 ng.ml-1 (normal, less than 0.12), respectively. Diltiazem was administered i. v. at a rate of 3 micrograms.kg-1.min-1 before induction of anesthesia. Anesthesia was induced with enflurane 2-3% and nitrous oxide in oxygen, followed by tracheal intubation facilitated with vecuronium. Anesthesia was maintained with enflurane 1-3% and nitrous oxide in oxygen. Paralysis was maintained with vecuronium. Hypertension during the manipulation of the tumor was controlled by increasing the inspired concentration of enflurane or by increasing the infusion rate of diltiazem to 5 micrograms.kg-1.min-1. There was no tachyarrhythmia. The infusion of diltiazem was continued until the draining vein from the tumor had been ligated. Hypotension, after removal of the tumor, was treated by the rapid infusion of fluid. Plasma norepinephrine and epinephrine levels during tumor manipulation were 1.18 ng.ml-1 and 6.57 ng.ml-1, respectively.

Adrenal Gland Neoplasms↗

PubMed1992

[A randomized study of pirarubicin (THP) versus adriamycin (ADM) for intravesical instillation therapy against superficial bladder cancer].

To determine the antitumor action by intravesical instillation prior to transurethral resection TUR, a randomized study on pirarubicin (THP) versus adriamycin (ADM) was performed for superficial, papillary and initially detected bladder cancers with participation of 21 Urological Clinics in 3 Tokai Prefectures. The instillation dose of 500 micrograms/ml was given 3 times per week for 3 weeks in both THP (n = 33) and ADM (n = 30) groups. The complete and partial response rates were 56.3% in THP group and 26.7% in ADM group. THP instillation was more effective against multiple tumors than a single tumor, stage Ta than T1 and grade G1 than G2 and G3. However, these findings were not statistically significant. Untoward effects were mainly bladder irritability and its frequency was 60.6% in the THP group and 23.3% in the ADM group. Contracted bladder was found in 2 of the 33 patients in the THP group and 2 of the 30 patients in the ADM group. The antitumor effect of a half dose of THP was equivalent to that of one dose of ADM, and the THP group showed a twofold higher frequency of side effects. Therefore, a clinical trial should be made comparing the effect of 500 micrograms/ml of THP and that of 1,000 micrograms/ml of ADM.

Administration, Intravesical↗

PubMed1992

Clinical experience of the Kock continent ileal urinary reservoir in 20 cases focusing on complications.

From August 1986 through July 1990, 20 patients underwent construction of the Kock continent ileal reservoir and were observed for more than three months. The early complications within the first 3 months were wound infection in four patients (20%), leakage at uretero-intestinal anastomosis in three patients (15%), prolapse of efferent limb and ileus in two patients (10%) and reflux, ureteral stenosis, intestinal fistula and postoperative pancreatitis in one patient (5%). The three late complications included stone formation in two patients and stenosis at an afferent limb in one patient. The stenosis occurred at the position of Dacron collar. The patients were divided into two groups and we compared the recent 10 patients with the initial 10 patients on complications and end results. In the initial group, 8 patients (80%) had 14 complications. In the recent group, 4 patients had 4 complications. The early complications have been reduced with the increase of Kock pouch operation. The result of the recent group was better than that of the initial group. Frequency of postoperative hydronephrosis in patients with Kock pouch was investigated. In nine patients (45%) the minimal hydronephrosis occurred within the first two months and in 5 patients (25%) three months after the operation. It had a normalizing tendency. The maximum pouch pressure at the pouch volume of 400 to 500 ml was not significantly high (37.9 +/- 12.2 cmH2O, mean +/- S.D.).

Adult↗

PubMed1991

Hajdu-Cheney syndrome: MR imaging.

Hajdu-Cheney syndrome is a rare congenital disease with acro-osteolysis, osteoporotic changes of the spine and long bones of extremities and marked basilar invagination with an unusually deformed skull. Magnetic resonance imaging of a 32-year-old male revealed the deformed skull and almost horizontal basal angle and the elongated and upwardly shifted brain stem caused by the tip of the odontoid process of the second cervical vertebra invaginating the base of the skull. In addition there were atrophic pituitary gland, widely open sella turcica and symmetrical fluid collections along the optic nerve sheath.

Adult↗

PubMed1991

Pallido-nigro-luysian atrophy, progressive supranuclear palsy and adult onset Hallervorden-Spatz disease: a case of akinesia as a predominant feature of parkinsonism.

Few parkinsonian patients present with 'pure akinesia' or with severe akinesia accompanied by only mild rigidity, tremor and other manifestations such as ophthalmoplegia. Pathological examinations of such cases have rarely been conducted and have revealed findings compatible with progressive supranuclear palsy (PSP), pallido-nigro-luysian atrophy (PNLA) or Parkinson's disease. We report a parkinsonian patient whose main clinical feature was akinesia. A postmortem study of this patient showed findings corresponding to PNLA and PSP. Histochemical properties of the pallidal pigment granules were equivalent to those of Hallervorden-Spatz disease (HSD) and striatonigral degeneration. In addition to iron-positive pigment granules, spheroids, severe neuronal loss and gliosis in the globus pallidus and substantia nigra, formation of Alzheimer's neurofibrillary tangle (NFT) in the brainstem shares characteristics with PSP, adult onset HSD and PNLA. We suggest that the underlying pathology of 'pure' akinesia is most often situated in the globus pallidus substantia nigra and subthalamus (Luys), and that PSP, PNLA and adult onset HSD may constitute a spectrum of one disease.

Atrophy↗

PubMed1991

Extensive proliferation of peripheral type myelin in necrotic spinal cord lesions of multiple sclerosis.

Peripheral type "remyelination" in the spinal cord was investigated in a 34-year-old woman with relapsing multiple sclerosis (MS) over 7 years following her initial presentation with myelopathy. Confined to the large necrotizing cord lesions involving the gray matter, there was prominent proliferation of peripheral type myelin, measuring up to one-third of the cross-sectional field of the cord. These nerve bundles with peripheral type myelin, which was devoid of glial fibrillary acidic protein immunoreactivity, consisted of relatively monotonous, small-caliber nerve fibers arranged in parallel along the long axis of the cord. The ratio of the myelin thickness to axonal diameter was not as small as that of the ordinary remyelination. Co-existing abundant neuroma formation indicated exuberant regenerative activity of the peripheral nerves. These findings suggest that the peripheral nerve fibers with their axons originating from nerve roots may enter the necrotic MS cord lesions in such a way as to manifest in spinal cord trauma. Relatively frequent occurrence of this extensive proliferation of peripheral type myelin in Japanese MS subjects appears to be related to the severity of tissue destruction experienced in Japanese as compared with that of occidental MS.

Adult↗

PubMed1991

Cerebral hypoperfusion correlates with mild and parenchymal loss with severe multi-infarct dementia.

Relative contributions of two potential pathogenetic factors for cognitive impairments among patients with multi-infarct dementia (MID) are reported. Cognitive test scores were correlated with measures of cerebral hypoperfusion and loss of brain parenchyma. Local cerebral blood flow values were determined utilizing stable xenon contrasted computed tomography and volumes for brain parenchyma were estimated from ratios of volumes of infarcted brain plus cerebrospinal fluid/total intracranial volume measured on the same CT slices among two groups of patients, one with mild and the other with severe MID. A total of 26 demented patients with multiple cerebral infarcts were divided into 2 index groups, one with mild and the other with severe MID (mild MID, CCSE greater than or equal to 15, n = 16; severe MID, CCSE less than 15, n = 10). Results were compared with similar measures among age-matched neurologically normal volunteers (n = 14). Ratios for volumes of lost brain parenchyma were significantly higher among severe MID patients than among age-matched normal volunteers, whereas estimates of brain loss among patients with mild MID did not differ from elderly normal volunteers. In patients with mild MID, LCBF values for cortical gray matter were decreased compared with age-matched normal volunteers. Results suggest that chronic cerebral hypoperfusion is an important determinant for mild dementia among patients in the early stages of MID, but volumes of lost cerebral parenchyma due to cerebral infarctions is an important determinant for advanced stages of MID.

Aged↗

PubMed1991

Cognitive recovery correlates with long-term increases of cerebral perfusion after head injury.

Prospective measurements of cerebral blood flow (CBF) and Cognitive Capacity Screening Examination (CCSE) were obtained following head injury among 42 patients for a mean total follow-up interval of 10 years. Clinical data obtained at the time of injury and detailed neurological examinations at each follow-up visit were correlated with serial CBF and CCSE scores. Comparisons of the group of patients who cognitively improved (n = 32) were made with the group that did not (n = 10). Of the total group, 76% showed cognitive improvements for as long as 10 years after injury, with CBF increases toward normal. Predictors for long-term cognitive improvements include: higher initial Glasgow Coma Scales, earlier recovery from coma, absence of signs of brain stem injury, and improvements of cerebral perfusion and autoregulation. Failure to improve correlated with low initial Glasgow Coma Scales, signs of brain stem injury, and persistent impairments of cerebral perfusion.

Adolescent↗

PubMed1991

Headaches due to cerebrovascular disease.

Subarachnoid hemorrhage causes sudden, severe headache and requires immediate medical and surgical diagnosis and treatment. A CT scan is the first choice for correct diagnosis. In order to prevent rebleeding, delays in treatment should be avoided. Intraparenchymal cerebral hemorrhage is now often recognized by means of CT scanning and sometimes is a cause of headache. Cerebellar hemorrhage commonly causes occipital headache and is an indication for immediate surgical intervention, although small cerebellar hemorrhages can be treated conservatively. Ischemic cerebrovascular disease is frequently accompanied by headache, but its etiology remains uncertain. Thrombosis of the cerebrovenous system is a less frequent cause of head pain than that of the arterial system, but it usually shows characteristic neurologic signs. Following carotid endarterectomy or superficial temporal artery-middle cerebral artery bypass surgery, the patient may have moderate to severe unilateral headaches, probably as a result of platelet aggregation and serotonin release.

Aortic Dissection↗

PubMed1991

Role of thalamus and white matter in cognitive outcome after head injury.

Local CBF (LCBF) and local partition coefficients (L lambda) were measured by xenon-enhanced computed tomography among 15 patients with remote cerebral trauma resulting from severe head injury. Results were compared with similar measures among age-matched normal volunteers (N = 20). The patients were divided into two groups according to different outcomes based on serial cognitive testing: Group I (N = 10) improved but Group D (N = 5) deteriorated throughout a mean interval of 10 years of follow-up. Initial LCBF measurements were performed at mean intervals of 6.8 years after injury. Cortical LCBF values were decreased in frontal (p less than 0.01) and temporal (p less than 0.05) regions among both groups, but only in Group D were flow values decreased in putamen and thalamus (p less than 0.05). L lambda values were reduced in frontotemporal cortex among both groups but in the thalamus only among Group D (p less than 0.05). Mean white matter flow values were normal in Group I but were reduced in Group D (p less than 0.05). Mean partition coefficients for white matter were reduced in both groups (p less than 0.01) but were lower in Group D (p less than 0.05). Reduced perfusion of frontotemporal gray matter is consonant with neuropathological reports following severe brain trauma of neuronal atrophy, gliosis, and infarction affecting these regions. Group comparisons between patients who cognitively improved versus those that deteriorated demonstrate an association between reductions of CBF in putamen, thalamus and subcortical white matter and impaired cognition after severe head injury.

Adolescent↗

PubMed1991

Morphological and functional heterogeneity in the rat prostatic gland.

Ductal morphogenesis and adult ductal branching patterns were examined in the rat prostate by a microdissection method. The rat prostate consists of paired (right and left) subdivisions which correspond in large part to the classically defined lobes: ventral prostate, lateral prostate, dorsal prostate, and coagulating gland. Of particular interest was the finding that the lateral prostate consists of two different ductal zones: (1) lateral type 1 prostate with 5-7 long main ducts (resembling miniature palm trees) that extend cranially towards both the seminal vesicle and dorsal prostate to arborize near the bladder neck, and (2) lateral type 2 prostate with 5-6 short main ducts that arborize caudal to the bladder neck and give rise to compact bushy glands. Both lateral prostatic groups had a ductal-acinar organization. The adult structure of the other rat prostatic lobes was also examined, and closely resembled their mouse counterparts. The ventral prostate, which had 2-3 pairs of slender main ducts per side, and the coagulating gland, which had 1 main duct per side, was completely ductal in structure. In contrast, the dorsal prostate, which had 5-6 pairs of main ducts per side, had a ductal-acinar structure. Ductal branching morphogenesis occurred at different rates in different lobes and was essentially complete in the prostate at the 30 days. Immunocytochemical studies with an antibody to DP-1, a major secretory protein of the rat dorsal prostate, revealed that secretory function was initiated at approximately 30 days after birth in the coagulating gland, the dorsal prostate, and lateral type 1 prostate. A consistent feature of the lateral type 2 prostate was the absence of DP-1. On Western blots, DP-1 was detected in the secretion of the coagulating gland, lateral type 1 and dorsal prostate, but not in the ventral and lateral type 2 prostate. Polyacrylamide gel electrophoresis confirmed this result and demonstrated that the lateral type 2 prostate expressed several low-molecular weight secretory proteins not found in the other lobes of the prostate. On the whole, the rat prostate exhibited considerable heterogeneity both between and within lobes in developmental processes, ductal patterning, histology, and functional expression.

Animals↗

PubMed1991

Cerebral white matter perfusion in dementia of Alzheimer type.

Local cerebral blood flow was measured in 19 patients with probable dementia of Alzheimer type (DAT) by using xenon-enhanced computerized tomography (CT) and CT densitometry to accurately differentiate white from gray matter. Patients met standard diagnostic criteria for probable DAT and results were compared with similar measures in 26 age-matched, neurologically and cognitively normal volunteers. Perfusions of frontal and occipital white matter as well as frontal, parietal, temporal, and occipital cortex were reduced in DAT compared with age-matched normals. White matter perfusion differences were not observed among DAT patients with and without risk factors for stroke. Reduced perfusion of frontal white matter correlated significantly with reduced perfusion of thalamus and putamen in patients with DAT. Results confirm the frequent association of white matter abnormalities in patients with DAT that are possibly caused by amyloid angiopathy and may contribute to cognitive impairments.

Aged↗