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Biomedical subjects

A Sakurai

Publications and source records attributed to A Sakurai.

At least 19 recordsLinked to original sources
PubMed2006

Purification, characterization, and potential applications of formate oxidase from Debaryomyces vanrijiae MH201.

Formate oxidase was found in cell-free extracts of Debaryomyces vanrijiae MH201, a soil isolate. After purification by column chromatography, the preparation showed a protein band corresponding to a molecular mass (MM) of 64 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The MM, estimated by a gel filtration, was 99 kDa. The preparation showed two and three bands on isoelectric focusing under denaturing and native conditions, respectively. These results suggest that the preparation contained three isoforms, each of which might be composed of alphaalpha, alphabeta, and betabeta subunits with apparently similar MM. The preparation acted on formate with K (m) and V (max) values of 11.7 mM and 262 micromol min(-1) mg(-1), respectively, at pH 4.5 and 25 degrees C, but showed no evidence of activity on the other compounds tested. The optimum pH and temperature were pH 4.0 and 35 degrees C, respectively. The preparation showed activities of 85% of the initial activity after storage at pH 6.0 and 4 degrees C for 8 weeks. When 10 mM formaldehyde was reacted with 2.0 U ml(-1) of the enzyme preparation at pH 5.5 and room temperature in the presence of 2.0 U ml(-1) of a microbial aldehyde oxidase and 100 U ml(-1) of catalase for 180 min, neither of formate nor formaldehyde was detected, suggesting that the reaction involved the quantitative conversion of formaldehyde to carbon dioxide.

Aldehyde Oxidase↗
PubMed2006

Rewarming following accidental hypothermia in patients with acute subdural hematoma: case report.

A 57-year-old man was admitted to the Emergency and Critical Care Department with accidental hypothermia (31.5 degrees C) after resuscitation from cardiopulmonary arrest (CPA). Brain CT revealed an acute subdural hematoma. Active core rewarming to 33 degrees C was performed using an intravenous infusion of warm crystalloid. The patient underwent craniotomy soon after admission, with bladder temperature maintained at 33 to 34 degrees C throughout the surgery. Therapeutic hypothermia (34 degrees C) was continued for 2 days, followed by gradual rewarming. After rehabilitation, the patient was able to continue daily life with assistance. Traumatic brain injury (TBI) following CPA is associated with extremely unfavorable outcomes. Very few patients with acute subdural hematomas presenting with accidental hypothermia and CPA have been reported to recover. No suitable strategies have been clearly established for the rewarming performed following accidental hypothermia in patients with TBI. Our experience with this patient suggests that therapeutic hypothermia might improve the outcome in some patients with severe brain injury. It also appears that the method used for rewarming might play an important role in the therapy for TBI with accidental hypothermia.

Hematoma, Subdural, Acute↗
PubMed2006

Clinical characteristics of postoperative contralateral intracranial hematoma after traumatic brain injury.

OBJECTIVES: To investigate the clinical characteristics of contralateral intracranial hematoma (ICH) after traumatic brain injury. METHODS: The subjects included 149 patients with traumatic ICH treated by hematoma evacuation. The patients were retrospectively divided into a bilateral ICH (B-ICH) group and unilateral ICH (U-ICH) group after craniotomy using brain CT scans for comparison of the following parameters: complicated expanded brain bulk from the cranial window, hypotension during craniotomy, and outcome. RESULTS: Post-craniotomy brain CT scans revealed U-ICH in 106 patients and B-ICH in 43 patients. Average Glasgow Coma Scale on arrival did not differ between the groups, but a higher proportion of patients in the B-ICH group deteriorated after admission (p = 0.02). The B-ICH patients also exhibited a significantly higher rate of expanded brain bulk from the cranial window (p < 0.05). No significant difference was observed between the groups with hypotension during craniotomy. The B-ICH group exhibited a lower rate of favorable outcome (p < 0.05) and higher mortality (p < 0.05). CONCLUSION: The B-ICH patients had a worse outcome than the U-ICH patients. Contralateral ICH was difficult to forecast based on pre- and intraoperative clinical conditions. Subdural hematoma or contusional ICH was frequently observed as a contralateral ICH.

Adolescent↗
PubMed2006

Changes in coagulative and fibrinolytic activities in patients with intracranial hemorrhage.

OBJECTIVE: To investigate whether any changes occur in the coagulative/fibrinolytic cascade in patients with subarachnoid hemorrhage (SAH) or hypertensive intracerebral hemorrhage (HICH). DESIGN AND METHODS: Subjects included 143 patients with intracranial hemorrhage (SAH, n = 50; HICH, n = 82; ROSC-SAH [return of spontaneous circulation after cardiopulmonary arrest due to SAH], n = 11). Coagulative and fibrinolytic factors were measured in blood samples taken on admission. RESULTS: The prothrombin fragment 1+2 level was significantly higher (p < 0.005) in SAH patients than in HICH patients. The fibrinolytic factors (plasmin alpha 2-plasmin inhibitor complex, D-dimer, or fibrinogen degradation products) in SAH and ROSC-SAH were both significantly higher than those in HICH, but the significance of difference was stronger in the case of ROSC-SAH (p < 0.05). DISCUSSION: Both coagulative and fibrinolytic activities were altered after the onset of SAH. These results demonstrate that the coagulative/fibrinolytic cascade might be activated via different mechanisms in different types of stroke. It remains unclear, however, whether a significant alteration of the fibrinolytic cascade in patients with ROSC-SAH might be a nonspecific phenomenon attributable to the reperfusion after collapse.

Blood Coagulation↗
PubMed2006

Brain oxygen metabolism may relate to the temperature gradient between the jugular vein and pulmonary artery after cardiopulmonary resuscitation.

OBJECTIVE: A gradient between the jugular vein temperature and core body temperature has been reported in animal and clinical studies; however, the pathophysiological meaning of this phenomenon remains unclear. This study was conducted to identify the temperature gradient between the jugular vein and pulmonary artery in comatose patients after cardiopulmonary resuscitation. MATERIALS AND METHODS: The temperatures of the jugular vein and pulmonary artery were measured in 19 patients at 6 and 24 hours after cardiopulmonary resuscitation. Jugular venous blood saturation (SjO2; %) was also measured concomitantly. The patients were divided into 2 groups: high SjO2 (SjO2 > 75%: H-group; n = 10) and normal SjO2 (SjO2 < or = 75%: N-group; n = 9). The temperature gradient was calculated by subtracting the temperature of the pulmonary artery from that of the jugular vein (jugular - pulmonary = dT degrees C). Statistical significance was defined as p < 0.05. RESULTS: dT was significantly lower in the H-group than in the N-group at 6 hours (0.120 +/- 0.011: mean +/- SD vs. 0.389 +/- 0.036: p = 0.0012) and 24 hours (0.090 +/- 0.005 vs. 0.256 +/- 0.030: p = 0.0136) after cardiopulmonary resuscitation. CONCLUSION: The temperature gradient between the jugular vein and pulmonary artery was significantly lower in patients with high SjO2 after cardiopulmonary resuscitation. This temperature gradient may be reflected in brain oxygen metabolism.

Body Temperature↗
PubMed2006

Organ dysfunction assessment score for severe head injury patients during brain hypothermia.

The purpose of this study was to evaluate the utility of a novel organ dysfunction assessment score developed for patients with severe traumatic brain injury during therapeutic brain hypothermia. The Brain Hypothermia Organ Dysfunction Assessment (BHODA) score is calculated through the combined assessment of 6 indices: central nervous system (CNS) function, respiratory function, cardiovascular function, hepatosplanchnic circulation, coagulation, and metabolism. The CNS, hepatosplanchnic circulation, and metabolic indices were based on measurements of cerebral perfusion pressure, gastric tonometry, and blood glucose, respectively. Thirty-nine patients with severe closed head injuries (scores of 3 to 8 on the Glasgow Coma Scale) were enrolled. Seven patients (18%) died during hospitalization. Outcome was favorable in 20 patients and unfavorable in 19. The BHODA score proved useful in describing sequences of complications during therapeutic brain hypothermia. A total maximum BHODA score of more than 13 points corresponded to a mortality of 70%. In a multivariate model, the total maximum BHODA score was independently associated with neurological outcome (odds ratio for unfavorable neurological outcome, 2.590: 95% confidence interval, 1.260, 5.327). In conclusion, the BHODA score can help assess multiple organ dysfunction/failure during therapeutic hypothermia and may be useful for predicting outcome.

Adolescent↗
PubMed2006

Acceleration of chemokine production from endothelial cells in response to lipopolysaccharide in hyperglycemic condition.

UNLABELLED: Chronic hyperglycemia is an established risk factor for endothelial damage. It remains unclear, however, whether brief hyperglycemic episodes after acute stress alter the function of vascular endothelial cells in response to endotoxin. We hypothesize that brief hyperglycemic episodes enhance the production of interleukin-8 (IL-8) after lipopolysaccharide (LPS) stimulation. METHODS: Human umbilical vein endothelial cells (HUVECs; 1 x 10(5) cells/mL, cells from subcultures 2-5, n = 6) were cultivated in various concentrations of glucose (200, 300, 400, and 500 mg/dL) with or without LPS stimulation (1 microg/mL) for 24 hours. After culture, IL-8 levels in the supernatant were measured using ELISA. RESULTS: HUVECs cultured at glucose concentrations of 300 and 400 mg/dL produced more (p < 0.01) IL-8 than control cells (200 mg/dL). HUVECs cultured at glucose concentrations of 300 and 400 mg/dL also produced more (p < 0.01) IL-8 than those cultured in the absence of LPS. CONCLUSIONS: Hyperglycemic conditions enhance IL-8 production by vascular endothelial cells, and this response is augmented by LPS. Infections may foster neutrophil accumulation at injury sites. These results suggest that it is important to manage even short-term increases in blood glucose after acute stress.

Cells, Cultured↗
PubMed2006

Importance of cerebral perfusion pressure management using cerebrospinal drainage in severe traumatic brain injury.

OBJECTIVE: To evaluate hemodynamics in patients with severe traumatic brain injury (TBI) after cerebral perfusion pressure (CPP) management using cerebrospinal fluid (CSF) drainage. METHODS: Twenty-six patients with TBI (Glasgow Coma Score = 8 or less) were investigated. Mean arterial blood pressure, CPP, cardiac index (CI), systemic vascular resistance index (SVRI), and central venous pressure were measured. The patients were divided into 2 groups after craniotomy: the intraparenchymal ICP (IP-ICP) monitoring group (n = 14) and ventricular ICP (V-ICP) monitoring group (n = 12). Patient hemodynamics were investigated on the second hospital day to identify differences. Measurements indicated a target CPP above 70 mmHg and a central venous pressure of 8 10 mmHg in both groups. Mannitol administration (IP-ICP group) or CSF drainage (V-ICP group) was performed whenever the CPP remained below 70 mmHg. RESULTS: High SVRI and low CI (p < 0.05) were observed in the IP-ICP group. The V-ICP group exhibited a reduction in the total fluid infusion volume of crystalloid (p < 0.01) and a reduction in the frequency of hypotensive episodes after the mannitol infusion. CONCLUSIONS: CPP management using CSF drainage decreases the total infusion volume of crystalloid and may reduce the risk of aggravated brain edema after excess fluid resuscitation.

Blood Flow Velocity↗
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

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↗
PubMed2002

On biased distribution of introns in various eukaryotes.

We conducted comprehensive analyses on intron positions in the Mus musculus genome by comparing genomic sequences in the GenBank database and cDNA sequences in the mouse cDNA library recently developed by Riken Genomic Sciences Center. Our results confirm that introns have a tendency to be located toward the 5' end of the gene. The same type of analysis was conducted in the coding region of seven eukaryotes (Saccharomyces cerevisiae, Plasmodium falciparum, Caenorhabditis elegans, Drosophila melanogaster, M. musculus, Homo sapiens, Arabidopsis thaliana). Introns in genes with a single intron have a locational bias toward the 5' end in all species except A. thaliana. We also measured the distance from the start codon to the position of the intron, and found that single introns prefer the location immediately after the start codon in S. cerevisiae and P. falciparum. We discuss three possible explanations for these findings: (1) they are the consequence of intron loss by reverse-transcriptase; (2) they are necessary to accommodate the function; and (3) they are concerned with the mechanism of pre-mRNA splicing.

Animals↗
PubMed2001

Pathological study of the diffuse myelin pallor in the anterolateral columns of the spinal cord in amyotrophic lateral sclerosis.

An immunohistochemical study using a monoclonal antibody against macrophage (Ki-M1p) was performed to examine which fiber tracts are affected in the spinal cords and brainstems of ALS patients. In 21 out of 30 ALS patients, various degrees of macrophage infiltration were observed diffusely in the anterolateral columns beyond the corticospinal tracts. On the other hand, a few macrophages were scattered in 20 non-ALS patients in the anterolateral columns outside the corticospinal tracts. In ALS brainstems, the macrophages were mainly localized in the corticospinal tracts. The result suggests that the diffuse myelin pallor in the anterolateral columns beyond the corticospinal tracts may be derived from intrinsic spinal cord lesions. Quantitative investigation using a monoclonal antibody against phosphorylated neurofilaments (SMI-31) revealed that the decrease in the numbers of small fibers would induce the diffuse myelin pallor in anterolateral columns of ALS patients. From these findings, we propose that the propriospinal bundles are candidates for the degenerating fibers in the anterolateral columns of ALS.

Adult↗
PubMed2001

Effect of reaction conditions on phenol removal by polymerization and precipitation using Coprinus cinereus peroxidase.

The quantitative relationships between removal efficiency of phenol and reaction conditions were investigated using Coprinus cinereus peroxidase. The most effective ratio of hydrogen peroxide to phenol was nearly 1/1 (mol/mol) at an adequate enzyme dose. 12.2 U of the enzyme was needed to remove 1 mg of phenol when our peroxidase preparation was used. At an insufficient peroxidase dose, the optimum pH value was 9.0, and lowering the reaction temperature led to the improvement of removal efficiency. At an excess peroxidase dose, almost 100% removal of phenol was obtained over a wide range of pH (5-9) and temperature (0-60 degrees C). Despite the presence of culture medium components, it was shown that Coprinus cinereus peroxidase had the same phenol polymerization performance as horseradish peroxidase or Arthromyces ramosus peroxidase.

Journal Article↗
PubMed2001

Effect of enzyme impurities on phenol removal by the method of polymerization and precipitation catalyzed by Coprinus cinereus peroxidase.

The removal of phenol by peroxidase-catalyzed polymerization was examined using the Coprinus cinereus peroxidases at different levels of impurity with respect to contamination. The phenol removal efficiency was improved by lowering the peroxidase purity. Acidic and high molecular weight proteins present as impurities in the peroxidase solution had some positive effect on the phenol-polymerizing reaction. The residual enzyme activity, either only in the solution or both in the solution and on the precipitate during the polymerizing reaction, was measured. The results indicate that the main effect of impurities in the peroxidase solution was the suppression of the adsorption of peroxidase molecules on the polymerized precipitate.

Adsorption↗
PubMed2001

Analysis of the cell-dependent replication potentials of human immunodeficiency virus type 1 vif mutants.

Eleven in-frame vif gene mutants of HIV type 1 produced in non-permissive cells were examined for their replication potentials in various CD4-positive and -negative cell lines. Virus replication for each mutant was monitored by using several single- and multiple-cycle infectivity assays. Except for a mutant with wild-type phenotype, most mutants were severely defective for replication in all the cell lines as expected from the producer cell-dependent functioning of Vif so far reported. In contrast, two mutants, which have mutations in the hydrophilic or effector regions of Vif were found to have target cell-dependent replication potentials. These results demonstrate the presence of a novel category of the vif mutants important for elucidation of the Vif function.

Amino Acid Sequence↗
PubMed2001

Ethanol production from starch by immobilized Aspergillus awamori and Saccharomyces pastorianus using cellulose carriers.

A simultaneous saccharification and fermentation (SSF) process was investigated to produce ethanol using two kinds of cellulose carriers that were respectively suitable for immobilization of Aspergillus awamori and Saccharomyces pastorianus. The maximum ethanol concentration attained by the batch operation was 25.5 g l(-1). Under suitable conditions, both cellulose carriers with immobilized cells could be reused efficiently for three cycles. The total amount of ethanol production was 66.0 g (per 1 l working volume) after the repeated operation. Ethanol productivity mainly depends on a saccharification process. There is a limit in durability in the repeated batch operation, and it is important to maintain high activity of the fungus in order to produce ethanol efficiently.

Aspergillus↗