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Biomedical subjects

J Suzuki

Publications and source records attributed to J Suzuki.

At least 649 records · Page 36Linked to original sources
PubMed1986

Evaluation of cerebral blood flow and metabolism in childhood moyamoya disease: an investigation into "re-build-up" on EEG by positron CT.

The cerebral blood flow and cerebral metabolic rate of oxygen (CBF and CMRO2) of three cases of childhood moyamoya disease were examined by positron-emission-computed tomography for the purpose of investigating the mechanism of the "re-build-up" phenomenon on EEG. Decrease in both CBF and CMRO2 were observed following hyperventilation. However, dissociation between the decrease in CBF and CMRO2 was also observed. Arterial blood-gas analysis disclosed hypocapnea during hyperventilation and hypoxia following hyperventilation. These results clearly indicate that the re-build-up seen on EEG is the manifestation not only of ischemic hypoxia but also of hypoxic hypoxia characteristically seen in moyamoya disease.

Adolescent↗
PubMed1986

Treatment of cerebral arteriovenous malformation.

The management of cerebral arteriovenous malformation (AVM) is discussed. A series of 231 cases of AVM was treated from 1961 to March 1984 in our department. The treatments of these cases are classified as total removal 169, partial removal 8, feeder clipping 14, embolization 4 and conservative 36. Results at discharge and at follow-up are analyzed and the treatment evaluated. At follow-up, no rebleeding is reported in the patients who had undergone extirpation. Cases treated with other methods showed rebleedings and either their condition worsened due to hemorrhages or they died. On the basis of these results, it is suggested that AVM should be extirpated totally. Our surgical procedure consisted of temporary occlusion of feeders using cerebral protective substances, so called "Sendai Cocktail" (mannitol, Vitamin E, steroid). This procedure makes complete surgery safe. Surgical results of the cases which were totally extirpated were better than those reported in previous reports: the mortality rate was 3.6%, and the morbidity rate was 5.4%. Because of this, surgical treatment was preferred, that is when the location, size of AVM, age, patient's circumstances and the surgeon's experience allow. However, there are still cases which must be treated with other therapy. These patients are withheld surgery because they have inaccessible AVM or large AVM etc., whose operation would cause neurological deficits. For the treatment of these cases we have recently attempt the chemical embolization method with conjugated estrogen. This produced good outcomes.(ABSTRACT TRUNCATED AT 250 WORDS)

Embolization, Therapeutic↗
PubMed1986

Effects of norharman on the mutagenicity of chlorophenylhydroxylamine and its metabolism with rat liver S9.

o,p-Chlorophenylhydroxylamines (CPHAs) (10468-16-3, 823-86-9) only demonstrated mutagenicity in the presence of S9 mix and norharman (NOH) (244-63-3), as well as chloronitrobenzenes. The mutagenic activity of o-CPHA was 30 times higher than that of p-CPHA. When o-CPHA was preincubated with S9 mix without NOH, the mutagenic activity disappeared rapidly. The decrease in activity during the preincubation was suppressed by addition of NOH. HPLC analysis revealed that o-CPHA was metabolized to o-chloroaniline (o-CA) (95-51-2) and that the metabolic reduction was inhibited by NOH. When microsomes containing NADPH were used instead of S9 mix, o-CPHA exhibited only very weak mutagenicity. The activity in the microsome system, however, was greatly enhanced by adding cytosol or ascorbic acid (50-81-7). These phenomena were only observed in the conventional plate incorporation method. In the case of the liquid incubation assay, in which test compound metabolism and tester strain mutation only occur in the liquid incubation medium, the mutagenic activity of o-CPHA in the microsome system with NOH was comparable to that in the S9 system, indicating that o-CPHA was activated by an enzyme in microsomes in the presence of NOH. Consequently, it was concluded that NOH not only affects the metabolic inactivation of o-CPHA to o-CA by S9, but also the metabolic activation of o-CPHA by microsomes. No appreciable enhancing effects of cytosol and ascorbic acid were observed in the liquid incubation assay, suggesting that these factors affect the stability of CPHA or an active metabolite. The microsome activation of o-CPHA was dependent on NADPH and oxygen; SKF-525A (62-68-0), metyrapone (54-36-4) and alpha-naphthoflavone (604-59-1) inhibited the mutagenic activity by about 50%, suggesting that cytochrome P-450 was involved in the metabolic activation.

Alkaloids↗
PubMed1986

Radical surgery on cavernous angioma of the brainstem.

Four cases of cavernous angioma of the brainstem are reported. Three patients had angiomas of the pons; one had a lesion extending from the third ventricle to the hypothalamus. In the three patients directly operated upon the entire lesion was excised. The lesions were delimited by reactive scar tissue, so that by means of a careful technique severe associated disorders were avoided postoperatively. The importance of computed tomography for postoperative observation and the effectiveness of nuclear magnetic resonance-computed tomography have been demonstrated. It is thought that henceforth surgical treatment of brainstem lesions will be found appropriate in a far greater number of cases.

Adolescent↗
PubMed1986

Bilateral symmetrical middle cranial fossa arachnoid cysts in a neonate.

A newborn girl was admitted suffering from convulsive seizures in both legs. A computed tomography (CT) scan revealed bilateral symmetrical middle cranial fossa arachnoid cysts and intraventricular hemorrhage. In the course of a year, only the cyst on the right side became gradually larger; the cyst on the left side was reduced in size. At the age of 1 year and 2 months, her intellectual development was normal, but she could not stand by herself. On metrizamide-enhanced CT cisternography, the cyst on the right side was of a noncommunicating type. Membranectomy of the right-sided cyst was performed and the cyst proved to be of the intraarachnoid type. The postoperative course was uneventful and a CT scan, taken 10 months after the operation, revealed no abnormality on either side. The intellectual and motor development was normal, and no abnormality was observed by electroencephalography. This may be the first report of arachnoid cysts found in a neonate. It gives us clues for understanding the etiology of this disease, which has not been fully clarified.

Arachnoid↗
PubMed1986

Noninvasive study of the presystolic component of the first heart sound in mitral stenosis.

Echophonocardiography and pulsed Doppler echocardiography were performed in 30 patients with mitral stenosis (19 with atrial fibrillation and 11 with sinus rhythm) to investigate the genesis of the presystolic component or small apical vibrations preceding the first heart sound in mitral stenosis. In 27 patients, mitral valve closure preceded or coincided with tricuspid valve closure regardless of the preceding RR interval. Of three patients whose tricuspid valve closed prematurely, two had a prolonged PR interval. The soft apical vibrations, which were recorded during the final rapid closing motion of the mitral valve echogram (B-C slope), began with the upstroke of the apexcardiogram. During this event the pulsed Doppler echocardiogram revealed a deceleration in the velocity of mitral inflow. In two exceptional patients with a prolonged PR interval, this apical sound was separated from a presystolic rumble that occurred during an accelerated phase of mitral inflow or at the A wave of mitral valve echograms. In conclusion, the tricuspid valve is not a factor contributing to the genesis of the small apical vibrations preceding the first heart sound in mitral stenosis. These vibrations are caused by acceleration of left ventricular contraction and deceleration of mitral inflow in the presence of a stenotic valve.

Adult↗
PubMed1986

Development of new cerebral protective agents: the free radical scavengers.

The generation of the free radical reaction in the ischaemic and hypoxic brain has been demonstrated using the chemiluminescence and the ESR techniques. The effects of various drugs, thought to be free radical scavengers were then tested in the ischaemic brain of dogs. It was found that not only mannitol, but also vitamin E, dexamethasone and other drugs have significant cerebral protective effects--particularly when administered together. Moreover, remarkable improvements were found when these 3 drugs were administered with the artificial blood substitute, PFC, which is known to have a high oxygen-carrying capacity. Finally, using the chemiluminescence and the ESR method, we have demonstrated that mannitol, vitamin E and glucocorticoids act as free radical scavengers and particularly mannitol acts as a scavenger of the hydroxy radical.

Animals↗
PubMed1986

Initiation and propagation of lipid peroxidation in cerebral infarction models. Experimental studies.

The possibility that cerebral ischaemia or cerebral hypoxia may initiate a series of free radical reactions in brain lipid constituents was explored by measuring sequential changes in chemiluminescence (CL) and electron spin resonance (ESR) during hypoxia or ischaemia load. Brain hypoxia was induced by means of arterial hypoxaemia (PaO2 17-22 mmHg), normocapnia (PaCO2 28-38 mmHg) and normotension (MABP 100-140 mmHg). To obtain lowered PaO2, 4% O2-96% N2 mixed gas was used for artificial ventilation. Spin trapping technique was used in ESR measurement and applied to the detection of free radicals generated in the ischaemic brain homogenate of three-vessel occlusion rat model (global highly ischaemic model with basilar artery coagulation and bilateral carotid artery clipping). Chemiluminescence (CL) began to rise in hypoxic or ischaemic loading and indicates high amounts at an early period of post-hypoxic or ischaemic state. The CL spectroanalysis by wavelength showed five peaks at 480 nm, 520-530 nm, 570 nm, 620-640 nm and 680-700 nm in both hypoxic and ischaemic brain. ESR measurement revealed the PBN (phenyl-t-butyl nitrone) trapped radical, which has hyperfine splitting constants of AN = 16.2-16.5 G and AH beta = 3.6-3.8 G in ischaemia model. An analysis of sequential change of PBN adduct intensity shows a peak at 30 min of ischaemic loading and a marked increase in the recirculation period. Preservation of ATP and marked lactic acidosis were seen in the 5 min hypoxic loading, elsewhere depletion of ATP and marked lactic acidosis were seen in the 5 min, 30 min ischaemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Asymmetrical head-turning of preterm infants: some effects on later postural and functional lateralities.

Asymmetrical head-turning and its effects on subsequent functional lateralities and postural asymmetries were examined in 44 relatively low-risk preterm and 53 fullterm infants. Persisting head-turning to the right was observed more often among preterm infants, as was an asymmetrical skull with flattened right occiput and head-turning to the right. Asymmetrical trunk posture was present in 20 preterm and four fullterm infants. At nine months right-hand preference was more marked in preterm infants, and hand preference was well coincident with head-turning. Changes in hand preference occurred more often among fullterm infants. Asymmetrical gait seemed to correlate with head-turning in preterm infants.

Functional Laterality↗
PubMed1986

Effects of lung inflation on blood flow during cardiopulmonary resuscitation in the canine isolated heart-lung preparation.

Using an isolated, fibrillated canine heart-lung preparation, we studied the effects of simultaneous lung inflation and chest compression on blood flow in a model of cardiopulmonary resuscitation. The heart and lungs were placed in an artificial thorax with the great vessels and trachea exteriorized and attached to an artificial perfusion circuit and respirator, respectively. The blood volume of the system was adjusted to obtain various levels of static equilibrium pressure. Blood flow was obtained by cyclically raising and lowering the pressure in the artificial thorax, simulating the changes in pleural pressure that occur during cardiopulmonary resuscitation. Lung inflation during the compression phase caused an increase in cardiopulmonary resuscitation blood flow when the change in pleural pressure was small and when static equilibrium pressure was high. In contrast, lung inflation caused a decrease in blood flow when changes in pleural pressure were high and when blood volume was low. These results suggest that the driving pressure for blood flow during chest compression may be increased by lung inflation when the pulmonary blood vessels are filled with blood. However, blood may become trapped in the right heart and unavailable for transfer to the periphery during chest compression if lung inflation causes the alveolar blood vessels to collapse.

Animals↗
PubMed1986

Quantitative method for measuring adjuvant-induced granuloma angiogenesis in insulin-treated diabetic mice.

The angiogenesis of adjuvant-induced pouch granuloma was studied in insulin-treated diabetic mice by a newly established method using carmine dye. The 10% carmine suspension in 5% gelatin solution was infused through the tail vein of mice to be distributed to the end of the capillaries in the granulation tissue without leakage. The carmine dye was extracted from the tissue with 3 N NaOH solution and then measured by spectrophotometry. The content of carmine dye in the granuloma tissue in alloxan diabetic mice was observed to be significantly low during the first week after adjuvant injection when compared with normal mice, indicating poor development of blood vessels in the diabetic state. Diabetes-induced inhibition of the angiogenesis was completely restored by the treatment with insulin in a dose producing no hypoglycemic effect. These results were directly reflected by the formation of granuloma tissue. This method was established to be explicitly useful for measuring the angiogenesis, especially in mouse granuloma tissue.

Angiography↗
PubMed1986

[Mechanism of action of pronase on chronic proliferative inflammation including granuloma angiogenesis in mice].

Effects of pronase on granuloma angiogenesis and granulation tissue formation were investigated using granuloma pouches induced by Freund's complete adjuvant containing 0.1% croton oil in normal and alloxan diabetic mice. Granuloma angiogenesis was measured by the carmine dye infusion method. Pronase (2 mg/kg/day) was daily injected into the pouch for 3 to 7 days, and its effects were compared with those of hydrocortisone (1 mg/kg/day) and indomethacin (2 mg/kg/day). Pronase significantly inhibited the wet weight of pouch granuloma, mainly in the later stage of inflammation in normal mice. But it failed to decrease both the content of hydroxyproline in granuloma and the amount of carmine dye infused into the newly developed capillaries, whereas hydrocortisone and indomethacin significantly decreased them. In pathohistological findings, pronase increased angiogenesis and subsequently enhanced the repair rate by a dense arrangement of mature connective tissue, although hydrocortisone and indomethacin markedly decreased angiogenesis. In alloxan diabetic mice, granulation tissue was significantly produced less than that in normal mice. Hydrocortisone potentiated the decrease in granulation tissue formation of diabetic mice, whereas pronase did not markedly affect on it. The ratios of the amount of capillaries to the wet weight of granuloma tissue in pronase-treated mice were higher than those of control mice. Pronase was concluded to enhance angiogenesis in granuloma tissue in addition to the activation of collagenolysis and proteolysis.

Animals↗