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Biomedical subjects

Y Kuwabara

Publications and source records attributed to Y Kuwabara.

At least 127 records · Page 7Linked to original sources
PubMed1996

Nutrient-induced thermogenesis and protein-sparing effect by rapid infusion of a branched chain-enriched amino acid solution to cirrhotic patients.

An increase in the resting energy expenditure (REE) on indirect calorimetry was observed by rapid intravenous infusion of a branched chain-enriched amino acid solution into cirrhotic patients. The increases resulted in nutrient-induced thermogenesis (NIT). The percentage of energy expenditure (EE) derived from protein decreased significantly with the infusion of the amino acids. The present pilot study demonstrates that branched chain amino acids can be utilized as energy substrates and a protein-sparing effect occurs in patients with liver cirrhosis.

Aged↗
PubMed1995

Evaluation of neuropsychological function in patients with liver cirrhosis with special reference to their driving ability.

Ability to drive an automobile was evaluated in 16 patients with well compensated liver cirrhosis. Four tests were performed, namely the emergency reaction test, the continuous emergency reaction test, the signal confirmation test and the accelerator reaction test. Test scores were compared to those of a group of age-matched healthy volunteers. 31% of patients were found to be unfit to drive. Alcoholic cirrhotics fared as poorly as non-alcoholic cirrhotics. In patients with subclinical hepatic encephalopathy (defined by neuropsychologic testing), 44% were unfit to drive. Routine testing of cirrhotic patients for ability to drive could have a major impact on motor vehicle accident rates.

Adult↗
PubMed1995

Detection of angina-provoking coronary stenosis by resting iodine 123 metaiodobenzylguanidine scintigraphy in patients with unstable angina pectoris.

Resting iodine 123-labeled metaiodobenzylguanidine (123I-MIBG) scintigraphy was performed in 19 patients with unstable angina to determine if it can detect myocardial ischemia and identify the angina-provoking coronary artery. Visual assessment of 123I-MIBG single-photon-emission computed tomograms was related to coronary vessel stenoses revealed by arteriography at each vascular territory. Fourteen (74%) of 19 patients had regional 123I-MIBG-identified defects at areas with preserved thallium-201 perfusion. 123I-MIBG defects were highly positive at areas supplied by angina-provoking coronary arteries. The sensitivity and specificity of 123I-MIBG defects for identifying the angina-provoking coronary vessel were 71% and 78%, respectively. The interval between the most recent angina attack and imaging was shorter and the angina occurred more commonly after admission in patients with 123I-MIBG defects than in those without defects. These data suggest that repetitive myocardial ischemia impairs regional 123I-MIBG uptake and that this impairment persists for several days after perfusion has been restored. Thus resting 123I-MIBG scintigraphy is a useful noninvasive method to detect coronary stenoses provoking repetitive ischemia in patients with unstable angina in its acute phase.

3-Iodobenzylguanidine↗
PubMed1995

Straying phenomenon of migrating LHRH neurons and highly polysialylated NCAM in the chick embryo.

The present study on unilaterally incompletely placodectomized chick embryos revealed that arrival of migrating LHRH neurons into the forebrain area is dependent on the presence of a central projection of the olfactory nerve. When a fragment of the lateral and medial olfactory epithelium was spared the damage, a small number of LHRH-ir cells were found to migrate into the forebrain along a thin NCAM-H-expressing fiber bundle of the olfactory nerve. In embryos with large lesions which destroyed the lateral olfactory epithelium, the poorly developed NCAM-H-positive olfactory nerve fibers were arrested where they meet the NCAM-positive medial nasal branch of the ophthalmic nerve and frequently fused with this branch fiber bundle. In these embryos, no LHRH-ir cells were detected in the forebrain area. They were deviated from their regular migratory course to the NCAM-H-positive medial nasal branch fiber bundle. This straying phenomenon indicates that some structural support is apparently needed for the migration of LHRH-ir cells, but their migratory route is not completely programmed in their precursor cells in the olfactory placode. In cultures of placodal tissues, the coexistence of migrating LHRH-ir cells with NCAM-H-expressing neural elements was always confirmed. It is suggested therefore that not only the structural support for the migration but also the interaction between LHRH-ir cells and NCAM-H-expressing neural elements is a prerequisite for successful LHRH neuronal migration.

Animals↗
PubMed1995

Nigrofrontal dopaminergic function as assessed by 18F-dopa PET.

The existence of the nigrofrontal dopaminergic pathway has been demonstrated in neuroanatomical studies. We evaluated the presynaptic nigrofrontal dopaminergic function using 18F-dopa (FD) positron emission tomography (PET). The multiple time PET data in the frontal cortex from 20 to 70 min post-injection for FD were evaluated by Patlak analysis using the cerebellar time-activity curve as an input function. The frontal FD uptake rate constants could not be determined in 5 of 12 normal volunteers because of large deviations in the plots. There were no significant differences between the subjects among whom the frontal FD uptake rate constants could or could not be determined regarding the amount of FD injected, the frontal 18F counts, or whether or not they were pretreated with carbidopa. The uptake constants were determined in 9 or 12 patients with parkinsonian syndrome. While the mean (+/- S.D.) uptake constants in patients with Parkinson's disease (2.89 +/- 0.06 x 10(-3), n = 4) and in patients with progressive supranuclear palsy (2.81 +/- 0.10 x 10(-3), n = 3) were not significantly different from those in the normal volunteers (2.93 +/- 0.14 x 10(-3)), those in two patients with corticobasal degeneration (2.42 and 2.46, respectively) decreased in comparison to the control values. Differences in the nigrofrontal presynaptic dopaminergic function as assessed by FD-PET may explain the different pathogenesis and also help to differentiate between corticobasal degeneration and other parkinsonian syndromes, such as Parkinson's disease and progressive supranuclear palsy.

Adult↗
PubMed1995

A case of true hermaphroditism with androgen insensitivity.

A phenotypically normal woman with a 46, XY karyotype was found to have a testis, an ovotestis, bilateral rudimentary uteri, and bilateral fallopian tubes. The endocrinological and pathological aspects of these findings are discussed.

Adult↗
PubMed1995

Time dependency of the acetazolamide effect on cerebral hemodynamics in patients with chronic occlusive cerebral arteries. Early steal phenomenon demonstrated by [15O]H2O positron emission tomography.

BACKGROUND AND PURPOSE: The acetazolamide effect is thought to reach a maximum at 10 to 20 minutes after administration. However, we sometimes encountered patients who showed a transient deterioration of ischemic symptoms several minutes after acetazolamide administration. We therefore considered that a steal phenomenon may occur before the acetazolamide effect reaches a maximum. We evaluated the time dependency of the acetazolamide effect on cerebral hemodynamics in patients with severe stenosis or occlusion of the unilateral internal carotid artery. METHODS: The subjects consisted of 13 patients with severe stenosis or occlusion of the unilateral internal carotid artery. Regional cerebral blood flow was measured at the resting state and at 5 and 20 minutes after the intravenous administration of 1 g acetazolamide by the use of the [15O]H2O bolus-injection method and positron emission tomography. The steal phenomenon was interpreted as positive when the regional cerebral blood flow values decreased by more than 10% after the administration of acetazolamide in more than one region of interest. RESULTS: A steal phenomenon was observed in 5 of 13 patients at 5 minutes after acetazolamide administration on the occlusive side, whereas it was observed in only 1 patient at 20 minutes. Thus, this phenomenon was observed more frequently in the early phase of the acetazolamide test. It was also observed more frequently in patients with poorly developed collateral circulation. CONCLUSIONS: Our acetazolamide [15O]H2O positron emission tomography study revealed an early steal phenomenon at 5 minutes after intravenous administration of acetazolamide, which may be a cause of the transient deterioration of ischemic symptoms during the acetazolamide test.

Acetazolamide↗
PubMed1995

Can transcranial Doppler really detect reduced cerebral perfusion states?

BACKGROUND AND PURPOSE: This study was designed to determine whether transcranial Doppler ultrasonography (TCD) may detect reduced perfusion states of the brain in patients with hypertension or diabetes mellitus with suspected cerebral atherosclerosis and arteriolosclerosis. METHODS: We determined blood flow velocity with TCD in the middle cerebral artery and cerebrovascular vasodilator responses to carbon dioxide in 22 patients with or without carotid artery occlusive disease and minor stroke; we compared the results with the measurements of cerebral blood flow and oxygen metabolism by positron emission tomography (PET). RESULTS: Blood flow velocity measured by TCD correlated with ipsilateral cerebral blood flow measured by PET in frontal, temporal, and striatal regions and throughout the entire hemisphere (P < .05 to P < .005). Relative changes in blood flow velocity and calculated cerebrovascular resistance tested by carbon dioxide inhalation both correlated closely with regional mean transit time (calculated as the ratio of cerebral blood volume divided by cerebral blood flow) in frontal, striatal, temporal, parietal, and occipital regions and also in the entire hemisphere (P < .05 to P < .0001). TCD variables did not correlate with hemispheric measurements of oxygen metabolism by PET. CONCLUSIONS: Although TCD is not useful in assessing impairments of cerebral metabolism, it is useful for detecting abnormalities of cerebral hemodynamics among patients with risk factors for cerebrovascular disease.

Adult↗
PubMed1995

[A comparison of the cerebrovascular responses to CO2 and Diamox in patients with unilateral occlusive cerebral arteries: a H2(15)O PET study].

We studied the relationship between the cerebrovascular responses to CO2 and Diamox in patients with chronic cerebrovascular diseases. The subjects consisted of 11 patients with unilateral occlusive or highly stenotic carotid artery. The cerebral blood flow was measured at the resting state, during the inhalation of 5% CO2, at both 5 and 20 min after Diamox i.v. (1 g). The rCBF ratios (occlusive/non-occlusive side) during the inhalation of CO2 and 20 min after Diamox i.v. closely correlated with each other. However, the ratio at 5 min after Diamox i.v. was slightly lower than that during the inhalation of CO2. The percent increases of rCBF also showed a significant correlation between 5% CO2 inhalation and 20 min after Diamox i.v. However, the rCBF decreased inversely at 5 min after Diamox i.v. in some regions on the occlusive side, which indicates the presence of a so-called "steal phenomenon". The percent increases in the rCBF after 1 g Diamox i.v. were more or equal to those during the inhalation of 5% CO2. The CO2 and Diamox were thus considered to be equally useful in the evaluation of the perfusion reserve capacity. However, these various characteristics as described above should be considered in the clinical practice.

Acetazolamide↗
PubMed1995

[The relationship between the cerebral blood flow, oxygen consumption and glucose metabolism in primary degenerative dementia].

The CBF, CMRO2 and CMRGlu were measured in patients with primary degenerative dementia including 5 patients with dementia of Alzheimer's type and 4 patients with Pick's disease, and then the correlation between the cerebral blood flow and energy metabolism was evaluated. The control subjects consisted of 5 age-matched normal volunteers. The CBF, CMRO2 and CMRGlu decreased in the bilateral frontal, temporal and parietal regions in the patients with Alzheimer's dementia, while they decreased in the bilateral frontal and temporal regions in the patients with Pick's disease. Both the CBF and CMRO2 were closely correlated with each other. However, the CMRGlu was more severely impaired than the CBF or CMRO2 in both pathological conditions. These results suggested that CMRGlu began to decrease before the reduction of the aerobic metabolism and thus measuring the CMRGlu is considered to be the most sensitive method for detecting abnormal regions in primary degenerative dementia.

Aged↗
PubMed1995

[Cerebral hemodynamics and metabolism in patients with Moyamoya disease not demonstrating either cerebral infarct or hemorrhage on MRI].

We evaluated the cerebral hemodynamics and metabolism in Moyamoya patients who did not demonstrate either cerebral infarct or hemorrhage on MRI. The subjects consisted of 5 patients with Moyamoya disease (4 females and one male, aged from 15 to 40 years). The CBF, OEF and CMRO2 of the Moyamoya patients did not differ from those of the normal control subjects. The CBV did increase significantly in the cerebral cortices and striatum, but not in the cerebellum. The TT was also significantly prolonged in the frontal and parietal regions. The cerebrovascular CO2 response was markedly impaired in the frontal, temporal and parietal cortices. However, it was relatively preserved in the occipital cortex, thalamus and cerebellum. Thus, the cerebral hemodynamic reserve capacity decreased even in the Moyamoya patients not demonstrating either cerebral infarct or hemorrhage on MRI, and it should be considered in the management of these patients.

Adolescent↗
PubMed1994

Column-switching high-performance liquid chromatographic analysis of BO-2727, a new carbapenem antibiotic, in human plasma and urine by direct injection.

A column-switching high-performance liquid chromatographic method has been developed for the simple and sensitive analysis of BO-2727 (I) in human plasma and urine. Plasma samples were diluted with an equal volume of a stabilizer, and the mixture was directly injected onto the HPLC system. The analyte was enriched in a pre-treatment column, while endogenous components were eluted to waste. The analyte was then backflushed onto an analytical column and quantified with ultraviolet detection. Urinary concentrations were determined in a similar way except that the enriched analyte was eluted in the foreflush mode to a cation-exchange column used for chromatographic separation. The standard curves for the drug were linear in the range of 0.05-50 micrograms/ml in plasma and 0.5-100 micrograms/ml in urine. The limits of quantification for plasma and urine were found to be 0.5 micrograms/ml and 0.5 micrograms/ml, respectively. This method was used to support Phase I clinical pharmacokinetic studies.

Anti-Infective Agents↗
PubMed1994

Children with unilateral occlusion or stenosis of the ICA associated with surrounding moyamoya vessels--"unilateral" moyamoya disease.

The clinical features of 6 children who are probable sufferers of "unilateral" Moyamoya disease are here reported. They showed angiographic findings which were compatible with those of Moyamoya disease, albeit only on one side. They did not, however, show any basic aetiologic factors. The age of onset, the clinical symptoms and the findings of electroencephalography, angiography, and positron emission tomography in these cases were also quite similar to those in the cases of Moyamoya disease except for unilateral involvement. All 6 patients underwent either direct or indirect EC-IC bypass surgery. In 3 children who received encephalo-duro-arterio-synangiosis, an indirect bypass procedure, the collateral circulation was well formed postoperatively. In the follow-up study, 2 of the 6 cases starting with a unilateral lesion developed bilateral involvement later. However, the other 4 cases persisted in showing only unilateral involvement. These 4 cases may suggest the existence of "unilateral" Moyamoya disease in the paediatric age, and it is recommended that such cases be treated similarly to those of bilateral Moyamoya disease.

Carotid Artery, Internal↗
PubMed1994

Hyperammonemia induced in rats by inhalation anesthesia with ether.

Transient hyperammonemia was observed in rats after inhalation anesthesia with ether. The elevation of blood ammonia concentration induced by ether anesthesia was greatest in carbon tetrachloride injured and indomethacin-treated rats, but not observed in phenobarbital-treated rats. The results suggest interaction between ether metabolism and ammonia metabolism in the liver.

Ammonia↗
PubMed1994

Striatal 18F-dopa uptake and brain glucose metabolism by PET in patients with syndrome of progressive ataxia.

Striatal 18F-Dopa uptake and brain glucose metabolism were studied by PET with 6-L-[18F]flurodopa and [18F]fluorodeoxyglucose in 11 patients with syndrome of progressive ataxia. Five of the 11 patients were diagnosed as having cerebellar cortical degeneration (CCD), including 3 with late cerebellar cortical atrophy and 2 with Holmes type hereditary ataxia while 6 demonstrated olivopontocerebellar atrophy (OPCA). The caudate and putaminal 18F-Dopa uptake ratios to the occipital cortex in CCD showed no significant difference from those in the controls. On the other hand, those with OPCA decreased as compared to the controls. In addition, the cerebellar glucose metabolism in CCD decreased as compared to the controls, while that in the brainstem showed no significant decrease from the controls. The glucose metabolic rates both in the cerebellar hemisphere and in the brainstem in the OPCA patients decreased compared to the controls. The cerebral cortical, striatal and thalamic glucose metabolisms were normal in both the CCD and OPCA in groups. The appearance of a decreased glucose metabolism in the cerebellum is considered to be relevant in the genesis of cerebellar ataxia, even though their underlying diseases were different from each other. The differences in the glucose metabolism of the brainstem and in the nigrostriatal presynaptic dopaminergic function between CCD and OPCA as assessed by PET may be caused by differences in the pathophysiological mechanism between CCD and OPCA, and those differences appear to be useful when making a differential diagnosis of CCD and OPCA.

Adult↗
PubMed1994

Imaging study on the mode of development and changes in avascular necrosis of the femoral head in systemic lupus erythematosus: long-term observations.

To find out when and how avascular necrosis of the femoral head (ANFH) develops in patients with SLE who are receiving corticosteroids, we carried out a 3-yr prospective study using imaging methods. Twenty-three patients with SLE who were free of hip pain and radiographically negative were enrolled in the study. Initially, abnormal findings characteristic of ANFH were detected in eight (35%) and six (26%) patients on MRI and radionuclide uptake bone scanning, respectively. During a 3-yr observation period abnormalities on MRI, bone scanning and radiography were found in four, five and four patients, respectively and three patients developed hip pain. Analyses of imaging changes demonstrated that only a small proportion of patients (2/8, 25%) who initially showed abnormal MRI progressed to be radiographically positive for ANFH over the 3 years. High doses of corticosteroids over the 3-yr period were to be responsible for the emergence of change in MRI abnormalities. It is also suggested that abnormal MRI findings tend to develop either within a relatively short interval after the start of corticosteroid treatment or are associated with the exacerbation of SLE.

Adolescent↗