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Biomedical subjects

S Inao

Publications and source records attributed to S Inao.

At least 55 records · Page 3Linked to original sources
PubMed1995

Effect of intracarotid administration of 6-aminonicotinamide on cerebral blood flow in cats.

BACKGROUND AND PURPOSE: We evaluated the effects of an adenosine triphosphate blocker, 6-aminonicotinamide (6-ANA), on the cerebral blood flow (CBF), cerebral metabolism, and electroencephalogram of cats. METHODS: Catheters were inserted into the common carotid artery of 16 adult cats anesthetized with ketamine via the lingual artery. We measured CBF in the infused area by the inhaled hydrogen gas clearance method and analyzed the electroencephalogram frequency. Cerebral metabolism was estimated by oxygen extraction (vol/%) and glucose utilization (millimoles) using data arterial (aorta) and sagittal sinus blood samplings. A solution of 6-ANA (6.0 mg/mL) (n = 8) or saline (n = 8) was infused via catheter at 2.0 mL/min for 3 minutes followed by a 60-minute observation of CBF, cerebral metabolism, vascular resistance, and the electroencephalogram components, alpha-2 ratio [= alpha-2/(alpha-1+alpha-2)]. The effect of 6-ANA on capillaries was evaluated by extravasation of Evans blue dye and electron microscopic findings. RESULTS: Moderate reductions in CBF, cerebral metabolism, and the alpha-2 ratio were observed during the infusion of 6-ANA versus saline infusion (P < .05 by paired t test and ANOVA). Vascular resistance was significantly increased (P < .05). No abnormalities were observed in the capillaries of the infused hemisphere. CONCLUSIONS: Results indicated that 6-ANA produced a downregulation of cerebral blood flow in cats.

6-Aminonicotinamide↗
PubMed1995

Computerized tomography in the assessment of brain shifts in acute subdural hematoma.

Computed tomography (CT) was used to characterize brain shifts in 30 adult patients (mean age 51.9 years) with fatal supratentorial acute subdural hematomes (ASH) who were admitted within 3 hours of the head trauma. The Glasgow Coma Scale (GCS) score, hematoma width, and midline shift were tabulated. The width of the cistern surrounding the brainstem (CSBS) and the distance from the floor of the fourth ventricle to the posterior clinoid process (IVv-PC) were measured. Opening (+) or disappearance (-) of the suprasellar cistern (SC) was determined using axial CT. The data were compared with those in agematched controls (n = 26) using the Wilcoxon and Kruskal-Wallis tests. The hematomas in the SC(-) group (n = 22, mean GCS score: 3.8 +/- 1.0) were wider (p = 0.02) than those in the SC(+) group (n = 8, mean GCS score: 4.7 +/- 1.5). The CSBS in the SC(+) group was significantly smaller than that in the controls (p < 0.01). In the SC(-) group the CSBS was smaller and the IVv-PC was significantly larger than those in the controls (IVv-PC; p < 0.01) and the SC(+) group (IVv-PC; p < 0.05). In the evolution of brainstem shifts in ASH, when the SC is open the predominant vector is in the direction of the skull base, while when the SC is not observed, an axial vector shifts the brainstem.

Adolescent↗
PubMed1994

An assessment of progression of brain edema with amino acid levels in cerebrospinal fluid and changes in electroencephalogram in an adult cat model of cold brain injury.

We investigated the relationship between the changes of the electroencephalogram (EEG) and concentration of amino acids (AAs) in cerebrospinal fluid (CSF) using a model of cold brain injury. A cold injury was made over the motor area of anesthetized adult cats (n = 45). The AAs in CSF from cisterna magna and in the blood were assayed by liquid chromatography. Frequency components and spike discharges/100 s in EEG were evaluated. Data were obtained before production of the lesion and every hour for 8 hours after the lesion was made. The AA-levels and EEG after the lesion was made were compared with those obtained in the controls and the sham operation group: S-group (n = 10) which were not significantly different. Glutamate and aspartate were not detected but methionine and serine were detected in the control CSF and S-group. These AAs increased during the first 4 hours (p < 0.05) and decreased thereafter. Significant increases in spike discharge and disappearance of fast wave (p < 0.02), and increase in AAs were concurrently detected. The AAs originated from necrosis in the lesion. During the next 4 hours, increase of phenylalanine, tyrosine, and valine continued (p < 0.05). Slow wave components (p < 0.02) and precursor AAs of neurotransmitters in CSF increased in association with expansion of edema fluid. In conclusion, our findings showed that changes in the concentration of AAs in CSF are useful indices of progression of edema associated with brain contusion.

Alanine↗
PubMed1994

Progression of kaolin-induced hydrocephalus and changes in performance of operant tasks by rats.

The behavior of rats with progressive hydrocephalus was examined to detect early neurological deterioration. Kaolin solution was injected into the cisterna magna of 10 of 17 anesthetized 8-week-old male rats (day 0), and saline in the other 7 rats (control group). Reaction time (RT, sec) and error ratio (ER, %) of unanesthetized rats escaping from electrical stimuli toward a nonstimulated sheet within a box were recorded daily from day 4 until autopsy after 4 weeks. Three rats in the kaolin group died in acute stage. Rats were assigned to either severe (S) (n = 4) or moderate (M) (n = 4) group according to the degree of ventricular dilatation at autopsy. The RTs prolonged and ERs increased in the kaolin group and they reached their minimum values. Values after the minimum RT value on day 12 in the M-group and 22 in the S-group during the chronic stage were compared with those in the controls, which decreased throughout the experiments (P < 0.03). In all animals in the S-group RT was prolonged each day with a linear regression (P < 0.005), although ER was decreased (0.69 > P > 0.23). In 3 rats and in another rat in the M-group RT was prolonged (P < 0.04 and P = 0.19) and ER was decreased in 3 rats (two: P = 0.41; one: P = 0.01) and increased in one (P = 0.55). In conclusion, deteriorated motor function is more important for early diagnosis in progressive hydrocephalus than behavioral symptoms.

Animals↗
PubMed1994

Primary intraosseous orbital hemangioma: a case report and review of the literature.

Primary intraosseous orbital hemangiomas are rare tumors. Only 25 cases have been reported in the literature. Very few of them have multiple orbital bone involvement. We report a case with extensive involvement of the orbital roof, the medial and lateral walls of the orbit, and the lesser and greater wings of the sphenoid, and describe a unilateral extradural frontotemporal approach to excise the tumor and decompress the right superior orbital fissure and both optic nerves. A brief clinical and radiological review of the literature is presented.

Angiography, Digital Subtraction↗
PubMed1994

Dynamics of cerebral metabolism in patients with chronic subdural hematoma evaluated with phosphorous 31 MR spectroscopy before and after surgery.

PURPOSE: To determine whether the depression of cerebral bioenergetic metabolism caused by chronic subdural hematomas can account for neurologic dysfunction and whether the degree of metabolic depression may be useful for clinical assessment and therapy. METHODS: Sixteen patients who had chronic subdural hematomas with hemiparesis and/or mental disturbances underwent phosphorous 31 MR spectroscopy before and 10 to 14 days after surgery. Phosphorous 31 MR spectroscopy was also performed on 5 patients who had chronic subdural hematomas with only slight headaches who were treated by conservative therapy and on 10 healthy volunteers. RESULTS: The peroperative phosphocreatine-to-inorganic phosphate ratio (2.10 +/- 0.36) improved to normal values (2.69 +/- 0.44) after evacuation of hematomas. This improvement was accompanied by complete disappearance of hemiparesis and/or mental disturbance. Brain tissue pH also improved from 7.07 +/- 0.11 to 7.205 +/- 0.13 after surgery. On the other hand, patients who had chronic subdural hematomas with only slight headaches had the same phosphocreatine-to-inorganic phosphate ratio and brain intracellular pH as healthy volunteers. CONCLUSION: The phosphocreatine-to-inorganic phosphate ratio may be useful for determining when to operate on patients with chronic subdural hematomas and to assess the efficacy of treatment.

Acid-Base Equilibrium↗
PubMed1994

Total hip replacement using femoral neck bone to graft the dysplastic acetabulum. Follow-up study of 18 patients with old congenital dislocation of the hip.

We performed total hip replacement on 25 congenitally dislocated hips using corticocancellous bone from the femoral neck as a bone graft to reconstruct the deficient acetabulum. Two patients (two hips) died less than five years after surgery and three hips developed deep infection. We reviewed the remaining 20 hips at an average interval of 8.4 years (5.2 to 12.9). Their functional scores (modified Merle d'Aubigné and Postel) averaged 5.7 for pain, 5.1 for walking ability, and 4.2 for range of motion. Radiographs showed union and remodelling of the grafted bone in every case. There were radiological signs of aseptic loosening in three sockets (15%) without collapse of the grafted bone. None of the femoral stems was loose. No revision operation has been performed. Our results confirm the usefulness in the long term of femoral autografts for severe acetabular deficiency.

Acetabulum↗
PubMed1993

A squamous cell carcinoma originated from intracranial dermoid cyst.

A 59-year-old female had been treated for epilepsy over 20 years. She had frequent convulsive seizures in spite of medication and was admitted to our hospital in status epilepticus. CT showed low density cyst with calcified wall at right suprasellar region and irregular ring enhancement in the frontal lobe which was continuous with the cyst. Angiography revealed tumor stain in the venous phase. The frontal mass was removed with evacuation of the cyst. Pathological findings were suggestive of squamous cell carcinoma arising from the epithelial component of the pre-existing dermoid cyst. The patient died six months after the operation with severe hyperglycemia, ketoacidosis and hypotension probably due to chemical meningitis and hydrocephalus.

Brain Neoplasms↗
PubMed1993

A trans-orofacial approach for the removal of an extracranial meningioma in the skull base.

Two rare cases of extracranial meningiomas associated with intracranial masses are reported. From the roentgenological findings both of the tumors were regarded as being partly connected. The tumors were surgically treated 21 and 19 years, respectively, after the first removal of the intracranial masses. They appeared as nasal-oral and orbicular masses, respectively, and were histologically diagnosed as meningotheliomatous meningioma. In one case a partial removal of a naso-oral tumor, including a subtotal removal of the tumor in the lateral orbital cavity, was performed by Weber-Kocher's incision plus Krönlein's incision. In the other case a tumor was removed via a transoral route by a lateral retraction of one half of the mandible after cutting it into halves. Our operative approaches and origins of the tumor are discussed.

Cerebral Angiography↗
PubMed1993

Microcirculation in experimental brain oedema assessed by laser-Doppler flowmetry.

Continuous measurement of CBV and CBF by means of laser-Doppler flowmetry was performed to analyse the cerebrovascular response to water accumulation during brain infusion oedema in cats. The presence of an oedema generator elicits a continuous reduction of CBV and a transient reduction of CBF. With cessation of this mechanical force of oedema production, CBV and CBF returned to control levels. These results indicate that excess accumulation of water in brain tissue by itself does not decrease CBF even when the driving pressure of oedema fluid is present, but that brain oedema attenuates CBV only when a pressure gradient exists. These results suggest that there are microcirculatory changes in brain oedema before and after removal of the oedema generating focus. The laser-Doppler flow method is a useful technique for the continuous assessment of tissue perfusion.

Animals↗
PubMed1993

Magnetic resonance imaging assessment of brainstem distortion associated with a supratentorial mass.

Quantitative measurements of brainstem distortion and neural dysfunction were obtained in 25 cases of chronic subdural haematoma. The horizontal and rotational brainstem displacements were measured on axial and coronal MRI in all patients pre-operatively, and brainstem auditory evoked responses (BAERs) were obtained in 11 cases. Logarithmic relationships were noted on both horizontal and rotational displacements of the brainstem and cerebrum. The type of shift changed in the rostro-caudal direction. In the axial plane, the cerebral hemisphere shifts and rotates, the midbrain shifts laterally with no rotation, and the pons shifts minimally but rotates moderately. In the coronal plane, the marked rotation of the cerebral hemisphere and moderate rotation of the brainstem result in midbrain kinking, suggesting a downward displacement of the midbrain. The prolongation of BAER latencies and central conduction times correlated with septum shift. The results of peak-V latency indicated that brainstem rotation in the coronal plane reflects upper brainstem dysfunction most closely. This study presents objective measurements of brainstem displacement shown on MRI, and clarifies the relationships between anatomical and physiological changes in the brainstem that are associated with supratentorial lesions.

Adult↗
PubMed1993

Fastigial pressor response observed during an operation on a patient with cerebellar bleeding--an anatomical review and clinical significance.

The fastigial pressor response (FPR) consists of an abrupt rise in blood pressure and tachycardia with hyperpneic response. The FPR is an important sign in posterior fossa surgery for respiration in postoperative patients. The authors experienced a distinct pressor, tachycardiac, and hyperpneic response elicited when controlling bleeding using a bipolar coagulator forceps at the subfastigial white matter in a 72-year-old man with cerebellar hemorrhage. This response was confirmed by bipolar electrodes, which produced a weak current under deeper anesthesia by increasing the concentration of enflurane. The postoperative course of this patient was uneventful. A FPR was suggested to be mediated by axons passing between the nucleus fastigii and the fourth ventricle. These commissural fibers mediating the FPR were suggested to be countercurrent efferent pathways from both sides of the nucleus parabrachialis lateralis, located at the dorsolateral corner of the rostral pons. The authors conclude that the partial destruction of the subfastigial commissural fiber bundle did not result in permanent respiratory deficit. Fatal respiratory disturbance might be anatomically suggested by completely cutting off this fiber bundle.

Aged↗
PubMed1993

Type X collagen does not bind to matrix vesicles.

Cultured chick embryo tibial hypertrophic chondrocytes released matrix vesicles and Type X collagen into the culture medium. When the culture medium was filtered through a 0.1 micron nitrocellulose filter, both the matrix vesicles, measured as alkaline phosphatase, and the Type X collagen were retained quantitatively. None of the other collagen types in the culture medium was retained on the filter. Dissolution of the matrix vesicles on the filter in detergent solutions resulted in quantitative solubilization of the Type X collagen also. These results suggested that the Type X collagen was intimately associated with the matrix vesicles. However, when membrane filters that were composed of materials other than nitrocellulose, and that had a range of pore sizes, were used to filter the culture medium, the ratios of total matrix vesicles to total Type X collagen retained on the filters ranged from 53 (polysulfone membranes) to 0.3 (nitrocellulose-cellulose acetate membranes). Thus it is concluded that the quantitative retention of matrix vesicles and Type X collagen on 0.1 micron nitrocellulose filters was due to true filtration of the matrix vesicles and to selective adsorption of the Type X collagen. Removal of the noncollagenous extensions from the Type X collagen by brief pepsin or trypsin treatment converted the Type X collagen to its 45 kDa collagenous domain, which was no longer retained on nitrocellulose filters, suggesting that the adsorption of the Type X collagen on the filters was through one or both of its noncollagenous extensions. When the culture medium was subjected to ultracentrifugation to pellet the matrix vesicles, 98% of the membrane-associated alkaline phosphatase (matrix vesicles) was pelleted but only 15-20% of the Type X collagen was recovered in the pellet. These results indicate that matrix vesicles and Type X collagen are not the associated products of hypertrophic chondrocyte.

Alkaline Phosphatase↗
PubMed1992

Continuous recording of changes in intracranial pressure using interference echoes of ultrasonic wave: a preliminary report of practicality and clinical evaluation.

We attempted to examine intracranial pressure (ICP) noninvasively using probes receiving interference echoes of ultrasound from thin layers between the skull and the surface of the cerebrum. The reception of echo through bone flaps less than 5-mm thick was good. Normal adults (4) and patients (4) were examined by attaching ultrasound probes to the frontotemporal scalp. Recordings were performed during rest, Valsalva maneuver, hyperventilation, and pumping of a shunt-flushing device. Ultrasound recordings of ICP were compared with those of the scalp using two different time windows. The effect of scalp vessels on the ultrasound recordings of ICP was evaluated. The waves from a pressure transducer and the ultrasound probe were similar. This method was found to be useful for ICP recording.

Adolescent↗
PubMed1992

Coordinate inhibition of alkaline phosphatase and type X collagen syntheses by 1,25-dihydroxyvitamin D3 in primary cultured hypertrophic chondrocytes.

The effects of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) (2.3 x 10(-12) - 1.4 x 10(-6) [M]) on alkaline phosphatase, collagen, and cell proliferation were examined in primary cultured hypertrophic chondrocytes prepared from the distal epiphyseal growth plate of the tibias of 12-day chick embryos. 1,25(OH)2D3 showed time- and dose-dependent inhibitory effects on the alkaline phosphatase and collagen levels. The inhibition of alkaline phosphatase activity became detectable at 2 x 10(-11) [M] and reached 10% of control at 10(-7) [M]. The concentration of 1,25(OH)2D3 giving a 50% inhibition of the enzyme level was approximately 3 x 10(-10) [M]. Of the two extracellular collagen pools, a cell-associated matrix pool showed a more dramatic decrease (to 10% of control) than a culture medium pool (to 50% of control) at increased 1,25(OH)2D3 concentrations. The degree of inhibition was different for each type of chondrocyte-specific collagen (types II, IX, X, and XI). Types II and IX were inhibited in a parallel manner to only 60-80% of control. On the other hand, types X and XI were more greatly reduced up to 10% of control, and their dose-dependent inhibitory curves were similar to that of alkaline phosphatase. On cell proliferation, 1,25(OH)2D3 had a biphasic effect: stimulation at 10(-10)-10(-8) [M] and inhibition at higher levels. The results revealed the significant involvement of 1,25(OH)2D3 in the metabolism of two probable calcification-related products, alkaline phosphatase and type X collagen.

Alkaline Phosphatase↗
PubMed1992

Measurement of local directional pressures in the brain with mass.

In order to understand the effects and the direction of pressure transmitted from a mass lesion through various brain structures, miniature strain gauges were inserted in different brain locations in eight anesthetized monkeys. Mass lesions were created by inflating a balloon in either of two locations--subcortical in four animals (Group I) and deep (lateral to the caudate nucleus) in the other four animals (Group II). Anterior-posterior directed pressures were thus measured from a gauge placed in the parietal lobe, and lateromedially directed pressures (LM-dPs) were measured from gauges in the temporal lobe and midbrain. Intracranial pressure, systemic mean arterial pressure, and cerebral blood flow were also monitored. After balloon inflation was begun, temporal changes in pressure were recorded from gauges as percentage increase or decrease from baseline measurements. In both groups, balloon inflation caused a gradual increase in the parietal lobe anterior-posterior directed pressure with a concomitant increase in intracranial pressure and a decrease in cerebral blood flow. The temporal lobe gauge in Group I recorded an initial negative followed by a positive LM-dP with further balloon inflation. In Group II, this gauge recorded a positive LM-dP throughout. The midbrain gauges in both groups recorded an initial positive followed by a negative LM-dP. This reversal in the direction of pressure in the midbrain occurred just before the supratentorial pressure reached a peak and was noted to be concurrent with a sudden rise in mean arterial pressure and a decline in cerebral blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

In vivo brain water determination by T1 measurements: effect of total water content, hydration fraction, and field strength.

This work is concerned with the accurate quantification of brain water content under routine clinical conditions. Gelatin solutions of varying water content are first employed as a model of an edematous brain and longitudinal relaxation measurements are performed at proton Larmor frequencies of 5, 41, 63, and 100 MHz. These are followed with in vivo measurements in an experimental animal model of brain edema at 41 MHz. The results underscore the dominant role of total water content W in the relaxation process and verify the expected linearity between 1/T1 and 1/W. A scheme is presented and experimentally verified at 41 MHz for deducing the exact relationship of 1/T1 vs 1/W at any frequency. Knowledge of this relationship along with precise measurements of 1/T1 at a given field strength permits quantitative in vivo measures of brain water content to be obtained with a precision of about 0.01. It is concluded that routine, accurate, and noninvasive brain water measurements are possible by magnetic resonance imaging in a clinical environment.

Animals↗