Search PubMed⌕ Search

Biomedical subjects

N Hayashi

Publications and source records attributed to N Hayashi.

At least 37 records · Page 2Linked to original sources
PubMed2004

Diffusion property following functional hemispherectomy in hemimegalencephaly.

Diffusion-tensor imaging (DTI), a unique magnetic resonance technique for analysis of diffusion-anisotropy of the brain, can identify subtle white matter changes in vivo. To investigate changes of truncated neurofibers, DTI was conducted prior to and following functional hemispherectomy in a female infant for refractory epilepsy associated with hemimegalencephaly. Anisotropy of the amputated pyramidal tract decreased relative to the unaffected side after surgery, which reflects secondary degeneration in neurofibers. In DTI applied to infants, differentiation between developmental changes and changes associated with the current phenomenon must be evaluated cautiously. Standardization of diffusion-tensor analysis of developmental change is desirable.

Adult↗
PubMed2004

Comparative analysis and development of microsatellite markers on swine (Sus scrofa) chromosome 1qter.

Several quantitative trait loci (QTL) have been detected on SSC1qter (Sus scrofa chromosome 1qter), including QTL for the number of vertebrae, as reported in our previous study. To provide the tools for analysis of QTLs on SSC1qter, we constructed a comparative map of swine and human. In addition, we identified 26 swine STSs and mapped 16 of them on SSC1qter using the INRA - University of Minnesota porcine radiation hybrid (IMpRH) panel. We screened a BAC library using these swine STSs and developed 35 new polymorphic microsatellite markers from the BAC clones, of which 26 were informative in our reference family. We also mapped nine microsatellite markers we had isolated previously. Consequently a total of 44 new polymorphic microsatellite markers were located within a 60-cM region of SSC1qter, spanning from SW1092 to the telomere.

Animals↗
PubMed2004

Association of ALDH(2) genotypes and alcohol consumption with periodontitis.

There is little information regarding the association between alcohol consumption and periodontitis risk. We assessed whether alcohol consumption and ALDH(2) genotypes were associated with periodontitis. Subjects' lifestyle was examined by a self-administered questionnaire, and the percentage of pocket depths > or = 3.5 mm was used as a periodontal parameter. ALDH(2) genotypes were determined with the use of a PCR/RFLP method. Multiple logistic analyses showed that alcohol consumption was significantly associated with periodontitis, and its odds ratio was 1.98. There was no significant relationship between periodontal status and ALDH(2) genotypes. However, ALDH(2)*1/*2 subjects who consumed > or = 33 g/day of alcohol had a significantly greater percentage of pocket depths > or = 3.5 mm than those whose daily consumption was lower, while there was no significant difference in periodontal status associated with alcohol consumption in ALDH(2)*1/*1 subjects. Our results suggest that alcohol consumption may be a risk indicator for periodontitis in ALDH(2)*1/*2 subjects who consume larger amounts of alcohol.

Adult↗
PubMed2003

Charge-ordered state in single-crystalline CaFeO3 thin film studied by x-ray anomalous diffraction.

X-ray anomalous diffraction, together with a band-structure calculation, was employed to obtain a quantitative understanding of the charge-ordering state in a single-crystalline CaFeO3 thin film. The experimental result shows a characteristic energy dispersion of the nearly inhibited reflection at 150 K, implying Fe atoms split into two distinct states. The energy dispersion is in good agreement with the calculated spectrum based on the LDA+U scheme. The calculation also reveals an electronic structure of the system where holes in the oxygen orbital surround one of the distinct Fe atoms, in spite of the total electron number in both Fe atoms remaining unchanged.

Journal Article↗
PubMed2003

Serial diffusion-weighted imaging in a patient with MELAS and presumed cytotoxic oedema.

A patient with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) was studied with serial diffusion-weighted MRI (DWI) after stroke-like episodes and the apparent diffusion coefficient (ADC) was measured in an infarct-like lesion. In the acute and subacute stages, the affected area gave high signal on DWI and its ADC was much lower than that in a normal control region. In the chronic stage, the ADC became higher than that in normal brain. We therefore suggest that the stroke-like episodes did not cause vasogenic oedema but were related to energy failure and cytotoxic oedema.

Brain Edema↗
PubMed2003

Neuro-Behçet's disease: analysis of apparent diffusion coefficients.

Little is known about the diffusion properties of brain lesions in neuro-Behçet's disease (NBD). We looked at 19 NBD lesions (13 active, six chronic) in six patients, using diffusion-weighted MRI (DWI). We calculated the apparent diffusion coefficients (ADC) of the lesions and compared them with normal contralateral brain, expressing this ratio as relative ADC (rADC). The rADC was 1.29+/-0.33 in active and 1.44+/-0.47 in chronic lesions, i.e., significantly higher than in the control regions. Increased diffusivity in both active and chronic phases in NBD is different from the pattern in ischaemic infarcts, so that ADC analysis might be helpful for differentiating between these conditions.

Adolescent↗
PubMed2003

MR imaging of postischemic neuronal death in the substantia nigra and thalamus following middle cerebral artery occlusion in rats.

The goal of this study was to investigate apparent diffusion coefficient (ADC) and T(2) relaxation time (T(2)) in the substantia nigra and thalamus after middle cerebral artery occlusion in rats. In the substantia nigra ipsilateral to infarct, ADC was significantly lower and T(2) was significantly higher on the third and fourth days, but they did not change significantly on the first, second, eighth and 15th days. In the ipsilateral thalamus, ADC and T(2) did not change significantly between the first and fourth days, but were significantly lower on the eighth and 15th days. This combination of MR findings suggested that secondary degeneration in the thalamus was different from that in the substantia nigra.

Animals↗
PubMed2003

Relation between brain oxygen metabolism and temperature gradient between brain and bladder.

Brain temperature is slightly higher than systemic core temperature normally. Fluctuations of a temperature gradient between brain and core body have recently been reported after a severe brain insult. The pathophysiological significance of the gradient fluctuations is unclear. This study aims to identify the gradient fluctuations between brain and core temperatures after a brain insult. Temperature gradient (brain temperature minus bladder temperature: degrees C) was measured in 11 patients (125 points) with severe brain injury (4 patients with subarachnoid hemorrhage, 4 with cerebral hemorrhage. and 3 with traumatic brain injury). Cerebral perfusion pressure (CPP; mmHg) and jugular venous blood saturation (SjO2; %) was also measured. The average gradient was 0.29 +/- 0.285 degrees C when CPP was above 50 mmHg. SjO2 was inversely related to the temperature gradient in a significant manner (r = 0.472; P < 0.0001). Temperature gradients tended to increase and then decrease when CPP < 50 mmHg. This study demonstrates that increased temperature gradient has a significant inverse correlation with SjO2 at CPP > 50 mmHg. The current results suggest that the fluctuations in temperature gradient in critical conditions reflect brain ischemia.

Adult↗
PubMed2003

Neuronal damage in pericontusional edema zone.

In this study, we investigated the molecular biological and histopathological aspects of the etiological mechanisms for pericontusional edema zone (PEZ). The subjects were 5 patients with traumatic brain injury who underwent surgery to evacuate the resulting hematoma. The average age of the subjects was 52 +/- 27.5 years. The GCS at the time of admission was 5-9. At operation apart from evacuating the hematoma, the PEZ was also excised and then examined histopathologically. Cerebrospinal fluid (CSF) levels of IL-6, IL-8, and IL-10 were measured at the time of admission and at 24 and 72 hours. Histological examination revealed large numbers of neutrophils accumulating within blood vessels in the PEZ, with some focal migration. IL-6: CSF levels at the time of admission and at 24, 72, and 72 hours were 550, 4350, and 878000 pg/ml, respectively (median values). IL-8: CSF levels were 715, 804, and 24900 pg/ml, respectively. IL-10: CSF levels were 15, 4, and 5 pg/ml, respectively. High levels of IL-6 and IL-8 were seen from an early stage, and became markedly higher with enlargement of the PEZ. The PEZ is thought to be due to microvascular disturbance by neutrophils stimulated by inflammatory cytokines, and neuronal damage from migrated neutrophils.

Adult↗
PubMed2003

Characteristics of parietal-parasagittal hemorrhage after mild or moderate traumatic brain injury.

UNLABELLED: The aim of this study is to clarify the clinical characteristics of parietal-parasagittal traumatic intracranial hemorrhage (TICH) after mild or moderate traumatic brain injury (TBI). METHODS; Subjects were 105 patients with mild or moderate TBI. The patients with parietal-parasagittal TICH were clinically analyzed based on the initial brain CT findings, hematoma sites and the clinical course as compared to those with TICH at other sites. RESULTS: Hematoma was located in the frontal or temporal lobes in 89.5% of the subjects and the parietal-parasagittal in 10.5%. Ten of the 11 patients suffering parietal-parasagittal TICH had skull fractures (7 depressed and 3 linear) but no depressed fracture observed in patients with frontal or temporal lobe hemorrhage. Neurological deterioration leading to a comatose state more frequently occurred in 63.6% of patients with parietal-parasagittal TICH than in those with frontal or temporal lobe hemorrhage (19.1%, p < 0.01). The incidence of hematoma growth was significantly higher in patients with parietal-parasagittal TICH (63.6%) than in those with frontal or temporal lobe hemorrhage (31.9%, p < 0.05). DISCUSSION: The incidence of parietal-parasagittal TICH is low, but the risk of neurological deterioration due to hematoma enlargement is significantly high. Parietal-parasagittal TICH may differ clinically from frontal-temporal TICH.

Adult↗
PubMed2003

IL-8 is a key mediator of neuroinflammation in severe traumatic brain injuries.

The subjects were 22 patients with severe head injury. The average age was 45 +/- 18.3 years. There were 13 survivors and 9 fatalities. Samples of peripheral blood and cerebrospinal fluid (CSF) were taken four times, at the time of admission and at 24, 72, and 168 hours later. IL-6: For the survivor group, peripheral blood levels were 181, 105, 37, and 26 pg/ml, respectively (median values). CSF levels were 5376, 3565, 328, and 764 pg/ml, respectively. For the fatality group, peripheral blood levels were 102, 176, 873, and 3059 pg/ml, respectively, whereas CSF levels were 15241, 97384, 548225, and 366500 pg/ml, respectively. IL-8: For the survivor group, peripheral blood levels were 36, 15, 15, and 15 pg/ml, respectively, whereas CSF levels were 23736, 4074, 355, and 1509 pg/ml, respectively. For the fatality group, peripheral blood levels were 21, 28, 43, and 77 pg/mL, respectively, whereas CSF levels were 29003, 8906, 5852, and 8220 pg/ml, respectively. IL-6 and IL-8 levels were significantly higher after 72 hours in the fatality group. The fact that CSF IL-8 was 1000 times that in the peripheral blood at the time of admission, and decreased thereafter, indicates that IL-8 is a key mediator of neuroinflammation.

Adult↗
PubMed2003

The risk factors for the occurrence of acute brain swelling in acute subdural hematoma.

There are many cases of acute subdural hematoma (ASDH) in which acute brain swelling (ABS) occurs intra- or post-operative period and the control of intracranial pressure becomes impossible, resulting in death. Consequently, we investigated the risk factors for ABS in ASDH. Thirteen cases were used for this study. The average age was 53.8 years, and all the subjects were males whose Glasgow Coma Scale (GCS) was an average of 4.8 when hospitalized. We examined the relationship of blood gas values (pH, PaO2, PaCO2, HCO3-, and base excess) when hospitalized, mean arterial blood pressure (MAP) before surgery, and the presence of hypotension during the surgery with ABS. There were no cases, which showed evidence of hypoxia or hypotension when hospitalized or before the surgery. No statistical differences in blood gas values when hospitalized were observed between the 7 cases with ABS and the 6 cases without ABS. However, all of 7 cases with ABS showed MAP > or = 140 mmHg, and 6 cases demonstrated intraoperative hypotension (systolic pressure < 90 mmHg). Conspicuous hypertension before the surgery was shown to be a possible risk factor for ABS. Therefore; MAP > or = 140 mmHg may be a warning sign for the occurrence of ABS.

Acute Disease↗
PubMed2003

Importance of hemodynamics management in patients with severe head injury and during hypothermia.

OBJECTIVE: To evaluate the hemodynamics in patients with traumatic brain injury (TBI) during therapeutic hypothermia. METHODS: Subjects were 25 patients with TBI (GCS; 8 or less). Mean arterial blood pressure (MAP), cerebral perfusion pressure (CPP), cardiac index (CI), systemic oxygen delivery (DO2), systemic vascular resistance index (SVRI), and pulmonary capillary wedge pressure (PCWP) were measured. Patients were retrospectively divided into 3 groups: normothermia (n = 5; NT), and survivors (n = 14; HT-S) and non-survivors (n = 6; HT-Non-S) after hypothermia. and hemodynamics were investigated for difference among groups at 24 hours from induction of normothermia or hypothermia. RESULTS: CPP target was above 70 mmHg, however, HT-Non-S could not maintain CPP above 70 mmHg. The low CPP was the result of elevated ICP, low MAP (P < .05), or both during hypothermia. In HT-Non-S, significantly high SVRI and low CI (P < .05) causing dehydration were observed during cooling. DO2 could not be maintained in HT-Non-S during hypothermia. CONCLUSIONS: These results suggest that patients run the risk of impairing hemodynamics during therapeutic hypothermia. Hemodynamic management is essential during hypothermia. If dehydration occurs during hypothermia. MAP may be reduced due to inadequate sedation, analgesia, and excess use of diuretic agents.

Blood Pressure↗
PubMed2003

Changes in cerebrovascular response during brain hypothermia after traumatic brain injury.

OBJECTIVE: Transcranial Doppler sonography (TCD) provides a rapid and noninvasive assessment of cerebral hemodynamics after traumatic brain injury. This study evaluates the change of cerebrovascular response at the rewarming stage of brain hypothermia using TCD. MATERIAL AND METHODS: Seventeen patients who had suffered from closed brain injury were investigated with daily TCD recordings and the changes in flow velocities were evaluated to determine whether they reflected the temperature during brain hypothermia. All patients who had treated brain hypothermia underwent continuous monitoring of SjO2, mean arterial blood pressure, and intracranial pressure (ICP). RESULTS: No significant changes in ICP and cerebral perfusion pressure (CPP) were recorded in all cases. Of 17 patients, 5 had a significant increase in SjO2 > 75% or more, retrospectively, with a robust increase in flow velocities of the middle cerebral artery (P < .01) at the rewarming stage. These cases marked a decrease in pulsatility index (P < .05) concomitant with an increase in SjO2 values. The CT scan revealed acute brain swelling in these cases. CONCLUSION: These data suggest cerebral vasoactivity could be altered at the rewarming stage. Hypothermia runs a risk of hyperemia at the rewarming stage, which induced a decrease in cerebral vasoresistance.

Acute Disease↗
PubMed2003

Association of the TAP2*Bky2 allele with presence of SS-A/Ro and other autoantibodies in Japanese patients with systemic lupus erythematosus.

We previously reported that a new allele of transporter associated with antigen processing (TAP) 2 gene, TAP2*Bky2 (Val577), was significantly increased in Japanese patients with Sjögren's syndrome (SS) and had a strong association with SS-A/Ro antibody production. In the present study, it was investigated whether the association of TAP2*Bky2 with SS-A/Ro antibody production was also found in Japanese patients with systemic lupus erythematosus (SLE). Polymorphisms of the TAP1 and TAP2 genes were determined in 114 Japanese SLE patients by the polymerase chain reaction-single-stranded conformation polymorphism (PCR-SSCP) method. The allele frequencies of the TAP1 and TAP2 genes in SLE patients were not significantly different from those in controls, although the allele frequency of TAP2*Bky2 was slightly higher in SLE patients than in healthy control subjects (9.2% vs 5.5%, P = 0.126). The allele frequency of TAP2*Bky2 was significantly higher in SLE patients with oral ulcers than in those without. It was noteworthy that TAP2*Bky2 was significantly associated with the appearance of not only SS-A/Ro antibody but also SS-B/La, nRNP, and Sm antibodies in the patients. The association of TAP2*Bky2 was found with the antibody production to both 60 and 52kDa SS-A/Ro antigens. As TAP2*Bky2 had a strong linkage disequilibrium with DRB1*08032, TAP2*Bky2 or its haplotype with DRB1*08032 may be involved in SS-A/Ro antibody production not only in SS but also SLE patients, indicating that TAP2*Bky2 may be a susceptible gene not only to the disease of SS but also to the SS-A/Ro autoantibody production.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2003

Identification of genes related to invasion and metastasis in pancreatic cancer by cDNA representational difference analysis.

The difference in gene expression between the highly invasive and metastatic cell line PC-1.0 and the weakly invasive and metastatic cell line PC-1 both derived from a pancreatic ductal carcinoma induced by N-nitrosobis (2-oxopropyl) amine (BOP) in Syrian golden hamster was examined using the Representational Difference Analysis (RDA) method. Within 8 clones (cDNA fragments) successfully isolated after subtraction hybridization of PC-1 cDNA from PC-1.0, 5 clones were shown to be specific or highly expressed in PC-1.0 as confirmed by RT-PCR. Among these 5 clones, two known genes, MAP kinase kinase 2 (MKK2) and phosphatidylinositol 4-kinase (PI4K230) were detected by gene sequencing. The specific expressions of MKK2 and PI4K230 in the highly invasive and metastatic cell line PC-1.0 were confirmed by RT-PCR and Northern blotting. By adding the CM of PC1.0 which included the cancer cell dissociation factor (DF), PC-1 cells began to dissociate and migrate from the colonies, and in addition the expression of MKK2 was found to be induced. On the other hand, the expression of PI4K230 was not induced in PC-1 cells by adding the CM of PC-1.0. Interestingly, in PC-1.0 the expression of PI4K230 was completely abolished and apoptosis induced by the PI3K inhibitor wortmannin. These results suggest that both MKK2 and PI4K230 are factors of a signal transduction pathway that might play an important role related to invasion and metastasis through the induction of cell motility and/or the inhibition of apoptosis.

1-Phosphatidylinositol 4-Kinase↗
PubMed2002

Two-dimensional thick-slice MR digital subtraction angiography in the assessment of small to medium-size intracranial arteriovenous malformations.

Assessment of intracranial arteriovenous malformations (AVMs) by conventional catheter angiography carries risks; moreover, this invasive procedure is often repeated for follow-up. We investigated the clinical applicability of two-dimensional thick-slice, contrast-enhanced magnetic resonance digital subtraction angiography (2D MRDSA) with high temporal resolution in the assessment of AVMs. We performed 78 2D MRDSA studies of treated or untreated small to medium-size AVMs on a 1.5 tesla imager. Two observers independently evaluated demonstration of nidus flow void on T2-weighted images and each component of the AVM on 2D MRDSA employing a three-point grading scale. In 55 patients with AVMs, the mean ratings of nidus flow voids, feeding vessels, nidi, draining vessels and early venous filling on MRI were 2.8, 2.4, 2.6, 2.8 and 2.8, respectively. sensitivity, specificity, positive and negative predictive values for an AVM using 2D MRDSA were 87, 100, 100 and 78%, respectively and for nidus flow voids on T2-weighted images 80, 91, 96 and 66%, respectively. 2D MRDSA can thus demonstrate haemodynamic features of AVMs. It can be employed as a less invasive, dynamic angiographic tool for follow-up of AVMs previously delineated by catheter angiography.

Adult↗