Biomedical subjects

O Tsuji

Publications and source records attributed to O Tsuji.

12 recordsLinked to original sources

PubMed2000

Contribution of edema and cerebral blood volume to traumatic brain swelling in head-injured patients.

OBJECT: The pathogenesis of traumatic brain swelling remains unclear. The generally held view is that brain swelling is caused primarily by vascular engorgement and that edema plays a relatively minor role in the swelling process. The goal of this study was to examine the roles of cerebral blood volume (CBV) and edema in traumatic brain swelling. METHODS: Both brain-tissue water and CBV were measured in 76 head-injured patients, and the relative contribution of edema and blood to total brain swelling was determined. Comparable measures of brain-tissue water were obtained in 30 healthy volunteers and CBV in seven volunteers. Brain edema was measured using magnetic resonance imaging, implementing a new technique for accurate measurement of total tissue water. Measurements of CBV in a subgroup of 31 head-injured patients were based on consecutive measures of cerebral blood flow (CBF) obtained using stable xenon and calculation of mean transit time by dynamic computerized tomography scanning after a rapid bolus injection of iodinated contrast material. The mean (+/- standard deviation) percentage of swelling due to water was 9.37+/-8.7%, whereas that due to blood was -0.8+/-1.32%. CONCLUSIONS: The results of this study showed that brain edema is the major fluid component contributing to traumatic brain swelling. Moreover, CBV is reduced in proportion to CBF reduction following severe brain injury.

Adolescent↗

PubMed1998

CSF dynamics in a patient with a programmable shunt.

The Codman-Medos programmable shunt system was designed by Drs. Hakim to relieve under and over drainage problems. The system allows for non-invasive post-implantation adjustment of the opening pressure of the valve through a range of 30 to 200 mmH2O in 10 mm differentials. However, its wide adjustability does not simplify determination of the optimal pressure setting. The bolus injection method was used to study the intracranial pressure environment of nine adult hydrocephalic patients treated with the Codman-Medos programmable shunt. Changes in CSF hydrodynamics with manipulation of the pressure valve setting, and the effectiveness of the bolus injection method to determine the optimum valve pressure setting were investigated. Initial valve pressure setting at shunt implantation was determined on the basis of preoperative CSF dynamics test. Another CSF dynamics test was carried out after surgery, and the pressure setting was revised in necessary. The new setting was the maximum obtained within normal CSF hydrodynamics. If shunt overflow was suspected, pressure was set at a higher level. After resetting of the shunt, no patient encountered serious shunt-related problems in the follow-up period. This method was considerably useful for understanding of the intracranial pressure environment of patients with a programmable shunt, and determination of a better shunt setting.

Adult↗

PubMed1997

Evaluation of homeostatic changes in CSF circulation: in vivo analysis of the effect of neurotransmitter accumulation in the extracellular space following transient global ischemia.

Accumulation of potassium and excitatory amino acids (EAA) in the extracellular space (ECS) following ischemia has been well documented. Careful monitoring of these transients is crucial to gain a better understanding of CNS pathophysiology. This study was initiated to determine if CSF concentrations of EAAs reflect those measured in the ECS. Transient global ischemia, 20 minutes in duration, was produced by clamping the left subclavian and innominate arteries combined with hemorrhagic hypotension. The accumulation of glutamate and electrolytes were measured in CSF and the extracellular fluid (ECF) of cerebral cortex. Microdialysis (MD) was utilized to measure the extracellular concentrations while direct sampling of CSF was provided via cannulation of the cisterna magna. Hydrogen clearance and laser doppler methods were used to monitor regional cortical CBF. Our results show that extracellular concentrations of potassium ([K+]ECF) and glutamate significantly increased following the initiation of ischemia (p < 0.05). The extracellular concentration of these substances decreased with the restoration of CBF. In CSF, a similar trend was observed following re-circulation (p < 0.05). However, CSF glutamate levels did not return to pre-ischemic values.

Animals↗

PubMed1996

Posttraumatic ventriculomegaly: hydrocephalus or atrophy? A new approach for diagnosis using CSF dynamics.

Cerebrospinal fluid (CSF) dynamics were correlated to the changes in ventricular size during the first 3 months posttrauma in patients with severe head injury (Glasgow Coma Scale score < or = 8, 75 patients) to distinguish between atrophy and hydrocephalus as the two possible causes of posttraumatic ventriculomegaly. Using the bolus injection technique, the baseline intracranial pressure (ICP), pressure volume index, and resistance for CSF absorption (R0) provided a three-dimensional profile of CSF dynamics that was correlated with ventricular size and Glasgow Outcome Scale (GOS) score at 3, 6, and 12 months posttrauma. Patients were separated into five different groups based on changes in ventricular size, presence of atrophy, and CSF dynamics. Group 1 (normal group, 41.3%) demonstrated normal ventricular size and normal ICP. Group 2 (benign intracranial hypertension group, 14.7%) showed normal ventricular size and elevated ICP. Group 3 (atrophy group, 24%) displayed ventriculomegaly, normal ICP, and normal R0. Group 4 (normal-pressure hydrocephalus group, 9.3%) had ventriculomegaly, normal ICP, and high R0. Group 5 (high-pressure hydrocephalus group, 10.7%) showed ventriculomegaly and elevated ICP with or without high R0. The GOS score in the nonhydrocephalic groups (Groups 1, 2, and 3) was better than in the hydrocephalic groups (Groups 4 and 5). It is concluded from these results that 44% of head injury survivors may develop posttraumatic ventriculomegaly. Posttraumatic hydrocephalus, as identified by abnormal CSF dynamics, was diagnosed in 20% of survivors and their outcome was significantly worse. This study demonstrates the importance of using CSF dynamics as an aid in diagnosis of posttraumatic hydrocephalus and identifying those patients who may benefit from shunt placement.

Atrophy↗

PubMed1995

Seasonal development of Leptotrombidium akamushi (Acari: Trombiculidae) under field temperatures.

Engorged larvae of Leptotrombidium akamushi (Brumpt), a vector of scrub typhus, were reared in small plastic containers placed on the ground and fed fresh eggs of the collembolan Sinella curviseta Brook. Engorged larvae obtained in October developed into deutonymphs through protonymphs approximately 1 mo before winter and became dormant in the cold winter season (approximately 3 mo). Most deutonymphs developed into tritonymphs in April and adults in May. Females began laying eggs in mid-June and the numbers of unfed larvae showed a peak in August. The mites reared from July rapidly developed into adults by August, and laid eggs in September. Larvae were most abundant in October, and adults became dormant in the winter. The same adults laid eggs from early May to late June and, upon hatching, the larval population peaked in early July of the 2nd summer. Most larvae died before the 2nd winter. Eggs hatched approximately 3 wk after oviposition and longevity of unfed larvae was 2 mo. Because of this very short incubation period, L. akamushi larvae occur in the summer, whereas L. pallidum Nagayo, Miyagawa, Mitamura & Tamiya, and L. scutellare Nagayo, Miyagawa, Mitamura, Tamiya & Tenjin occur in the autumn, although 3 species lay eggs from May to August.

Animals↗

PubMed1993

Measurement of vascular reactivity in head injured patients.

It is has been demonstrated that clinical outcome following head injury is correlated with the reactivity of the cerebrovasculature to carbon dioxide changes. Since CBF measurements are difficult to perform in these patients, a new technique is proposed utilizing the ICP response to capnic stimuli. In 40 head injured patients, the responses of ICP, pressure volume index (PVI) and middle cerebral artery velocities to hypocapnia and to hypercapnia were determined. Hypocapnia reduced ICP and MCA velocity while hypercapnia was followed by ICP and MCA velocity increases. Both changes were in the same magnitude supporting the concept the global ICP response reflects vascular reactivity. The fact that the velocity response to hypocapnia in lesioned hemispheres was less compared to the ICP response indicates the loss of ability to dilate in injured vessels and is consistent with earlier findings relating reduced reactivity to poor outcome.

Adult↗

PubMed1993

[Cefuzonam penetration into cerebrospinal fluid].

We studied the penetration of cefuzonam (CZON) into the cerebrospinal fluid (CSF) in 20 patients with neurosurgical diseases. Influences of the presence of meningeal reaction and the intensity of brain damage on CSF penetration of CZON were also examined. Concentrations of CZON in serum and CSF were determined using the thin-layer cup method before and 1, 2, 4, and 6 hours after 2 g of CZON was administered intravenously. The serum concentration at 1 hour was 60.4 +/- 31.3 (mean +/- S.D.) microgram/ml, then rapidly decreased to 2.1 +/- 2.3 micrograms/ml at 6 hours. In contrast, the CSF concentration gradually increased, reached a peak level of 0.319 +/- 0.313 micrograms/ml at 4 hours and then slowly decreased to 0.273 +/- 0.249 micrograms/ml at 6 hours. The CSF penetration ration: CZON ([CSF]/[serum]) was 5.6% at 4 hours. The peak CSF concentration in patients with meningeal reaction (0.465 +/- 0.364 micrograms/ml at 2 hours) was about 2-fold higher than that in those without the reaction (0.249 +/- 0.223 micrograms/ml at 4 hours). The peak CSF concentrations in patients with slight, moderate, and severe brain damage were 0.231 +/- 0.133 micrograms/ml at 4 hours, 0.270 +/- 0.232 micrograms/ml at 4 hours, and 0.680 +/- 0.467 micrograms/ml at 2 hours, respectively. CSF penetration of CZON was augmented in patients with meningeal reaction or severe brain damage. These findings indicate that the concentration of CZON in CSF after intravenous administration is sufficient for treatment of meningitis or infections after neurosurgical operations caused by such bacteria as Escherichia coli, Klebsiella pneumoniae, Haemophilus influenzae, and Streptococcus pneumoniae.

Adult↗

PubMed1975