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Biomedical subjects

F Gotoh

Publications and source records attributed to F Gotoh.

At least 73 records · Page 4Linked to original sources
PubMed1984

Noradrenergic nervous activity in migraine.

The autonomic nervous function in patients with migraine was studied during headache-free intervals. The following observations were made: (1) a decrease in overshoot in Valsalva's maneuver; (2) orthostatic hypotension; (3) low levels of plasma norepinephrine in the steady state; (4) failure in elevation of the plasma norepinephrine level after head-up tilting; (5) dilatation of the pupils after instillation in the eye of 1.25% epinephrine; and (6) a long recovery time in tests by bolus injection of 0.1 microgram of norepinephrine bitartrate per kilogram. The above findings suggest that patients with migraine show sympathetic hypofunction together with denervation hypersensitivity of the iris and the arteries, and that a defective noradrenergic nervous system may play a role in the pathogenesis of migraine.

Adult↗
PubMed1984

Blood flow velocity in the pial arteries of cats, with particular reference to the vessel diameter.

The blood flow velocity and diameter of feline pial arteries, ranging in diameter from 20 to 200 microns, were measured simultaneously using a newly developed video camera method under steady-state conditions for all other parameters. There was a linear relationship between blood flow velocity and pial artery diameter (y = 0.340x + 0.309), the correlation coefficient being 0.785 (p less than 0.001). The average values for blood flow velocity in pial arteries less than 50 microns, greater than or equal to 50 but less than 100 microns, greater than or equal to 100 but less than 150 microns, and greater than or equal to 150 microns in diameter were 12.9 +/- 1.3, 24.6 +/- 3.4, 42.1 +/- 4.7, and 59.9 +/- 5.3 mm/s, respectively. Blood flow rate was calculated as a product of the cross-sectional area and the flow velocity. The blood flow rate increased exponentially as the pial artery diameter increased (y = 2.71 X 10(-4) x2.98). The average values for blood flow rate in pial arteries less than 50 microns, greater than or equal to 50 but less than 100 microns, greater than or equal to 100 but less than 150 microns and greater than or equal to 150 microns in diameter were 12.8 +/- 1.5, 122.1 +/- 24.8, 510.2 +/- 74.8, and 1524.2 +/- 174.4 10(-3) mm3/s, respectively. Hemorheological parameters such as the wall shear rate and Reynolds' number were also calculated. The data obtained provide a useful basis for further investigations in the field of cerebral circulation.

Animals↗
PubMed1983

Creutzfeldt-Jakob disease: a case with extensive white matter degeneration and optic atrophy.

A 52-year-old woman is described, whose clinical features were typical of Creutzfeldt-Jakob disease except for the presence of optic atrophy. Serial CT scans showed rapid development of brain atrophy early in the course. Postmortem examination revealed extensive degeneration of the cerebral and cerebellar white matter and of the optic nerves in addition to the classic findings of Creutzfeldt-Jakob disease. It is suggested that both the grey and white matter may undergo a severe destructive process early in the course of the disease, and the possibility is discussed that the white matter involvement is not a result of neuronal loss.

Brain↗
PubMed1983

Prognostic value of cerebral blood flow autoregulation in the long-term prognosis of ischemic cerebrovascular disease.

The correlation between long-term prognosis, cerebral blood flow (CBF) and CBF autoregulation was studied in 34 patients with cerebral infarction (mean age, 64 years). CBF was measured by the nitrous oxide method 1-6 months (mean 87 days) after disease onset. CBF autoregulation was evaluated quantitatively from the Dysautoregulation Index (DI) (delta CBF/delta effective MABP). Reductions in effective MABP were induced with a tilt table. No significant correlation was noted among CBF, DI and activities of daily living at the time of measurement. The patients' physical condition was reevaluated by questionnaire 2 years or more (mean 32 months) later. Better functional state at follow-up was related to higher CBF and lower DI values although the differences were not significant. The relationships among CBF, DI and changes in physical condition during the period were evaluated. The mean CBF values in patients with a better prognosis exceeded those of poor prognosis patients. The CBF values in the group who became independent significantly exceeded those in the group that deteriorated (P less than 0.05). The CBF values in the latter showed small but significant decreases during head-up tilting (P less than 0.05). The DI in this group was significantly higher than in the groups with a less severe outcome (P less than 0.01, P less than 0.05, respectively). In conclusion, determinations of CBF autoregulation, together with flow values, in the chronic state may have some value in predicting the long-term prognosis in cerebral infarction.

Adult↗
PubMed1983

Transfer function through regional cerebral cortex evaluated by a photoelectric method.

A new technique is reported for obtaining the transfer function through the regional cerebral cortex. Tissue carbon-black (CB) dilution curves were recorded with a photoelectric apparatus used as a densitometer head in cat cortex in situ following intracarotid injection of 0.2 ml of 1/40 diluted CB solution. The linearity and stationarity of the vascular system, reproducibility of the curve, and recirculation were tested. The tissue CB dilution curve, a cumulative distribution function, was first differentiated yielding two curves comprising the inlet and outlet curves. The error due to "overlapping" was corrected for by extrapolation using the gamma-density function. The transfer function through the cortex was then calculated by numerical deconvolution of the inlet and outlet curves. The validity of the calculated transfer function was verified by comparison with that obtained from actual CB dilution curves recorded simultaneously from the pial artery and superior sagittal sinus. The transfer function was further subjected to moment analysis for determining the intraparenchymal circulatory parameters of the cerebral cortex. Some examples demonstrating the applicability of technique are given.

Animals↗
PubMed1983

Effects of hemolysis, hematocrit, RBC swelling, and flow rate on light scattering by blood in a 0.26 cm ID transparent tube.

The intensity of light scattering by blood in a tube of diameter 0.26 cm was measured with an apparatus devised by us at different angles on an incident cross-sectional plane. Changes in angular distribution of light intensity associated with hemolysis, and changes in hematocrit (Ht), red blood cell (RBC) swelling, and flow rate were plotted on polar coordinates. The dyssymmetry index, defined as the ratio of the intensity of light at 45 degrees to that at 135 degrees, was used to characterize the shape of the diagrams of light scattering. The index decreased with Ht, flow rate, but increased with RBC swelling. It is concluded that light scattering by blood requires intactness of the RBC membrane. Even when the cell membrane is intact, light scattering is subject to changes with the flow rate of blood, presumably due to RBC aggregation.

Animals↗
PubMed1982

Influence of cerebral venous obstruction on cerebral circulation in humans.

The influence of cerebral venous obstruction on cerebral circulation was investigated in three patients with cerebral venous and sinus thrombosis in the chronic stage. The xenon Xe 133 intracarotid injection method was used to evaluate the cerebral blood flow (CBF). Values for CBF showed a slight decrease in all patients, despite intact cerebrovascular autoregulation. In two of the three patients, hypercapnia failed to increase CBF, but hyperventilation decreased CBF normally. This phenomenon can be explained on the basis of both failure of the capacitance vessels on the venous side to dilate and an increased intracranial pressure and is not attributable to decreased carbon dioxide reactivity. Long-lasting obstruction of the venous system can lead to a slight reduction in CBF and not affect cerebral autoregulation or CO2 reactivity itself in humans.

Adolescent↗
PubMed1982

Long-term prognosis in ischemic cerebrovascular disease in relation to cerebral blood flow and metabolism.

The correlation between long-term prognosis and cerebral hemodynamics and oxygen consumption was investigated in 46 patients with ischemic supratentorial cerebrovascular disease. Cerebral blood flow (CBF) and cerebral oxygen consumption (CMRO2) were measured by the N2O method 1-6 months (mean 68 days) after disease onset. No significant correlation was observed among CBF, CMRO2 and activities of daily living at the time of measurement. The patients' physical condition was reevaluated by the questionnaire method 2 years or more (mean 53 months) later. The CBF values in patients who were independent after completion of the follow-up period significantly exceeded those of patients dying during the period (P less than 0.05). No correlation was observed in CMRO2. The relationship among CBF, CMRO2 and changes in physical condition during the period was evaluated. Mean CBF values in patients with better prognosis exceeded those of patients with poor prognosis. Notably, CBF values in the "improved" group significantly exceeded those in the "unchanged" or "died" group (P less than 0.05, P less than 0.01). CMRO2 was not significantly correlated with changes of physical condition. These results emphasize the importance of total CBF for long-term prognosis and indicate that flow values, rather than metabolic indices, obtained in the chronic stage can usefully predict the long-term prognosis.

Aged↗
PubMed1982

Video camera method for simultaneous measurement of blood flow velocity and pial vessel diameter.

A new method for the simultaneous measurement of blood flow velocity and pial vessel diameter is described. The system consists basically of a high-sensitivity vidicon camera, camera control, width analyzer, video densitometer, TV monitor, desktop computer, and multi-pen recorder. The pial vessels are visualized through a cranial window at 25-200x magnification on the TV monitor. The diameter of three target vessels can be recorded simultaneously on the recorder by adjustment of controllable video signal gates using the width analyzer. At the same time, the optical densities of two targets at points upstream and downstream of the pial vessel are measured continuously with video densitometers, and their outputs are recorded on the polygraph and analyzed by the computer. The time difference in the two peaks of time--concentration curves, produced very 2-3 s at the highest frequency by the injection of a small amount of saline through the lingual artery, is measured on-line using the computer. The flow velocity in the vessel is calculated from the time difference and the distance between the two targets. The system was shown to be stable, reliable, and rapid in response. This method may provide a useful tool for research in the field of blood circulation in the brain or any other organ.

Animals↗
PubMed1982

Effect of nimodipine, a calcium antagonist, on cerebral vasospasm after subarachnoid hemorrhage in cats.

Effect of a calcium antagonist, isopropyl-(2-methoxyethyl)-1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3,5- pyridinedicarboxylate (nimodipine) on the cerebral vasospasm after experimental subarachnoid hemorrhage (SAH) was studied in ten adult cats. The vasospasm was induced by injecting of 0.2-0.3 ml fresh autologous whole blood into the cisterna magna. Diameter of pial vessels was continuously measured by means of the vidicon camera system developed in our laboratory. Intravenous administration of nimodipine (0.1 mg/kg) 20-30 min after SAH resulted in a complete disappearance of the spasm with the reduction of blood pressure. The dilatory response was more marked in the smaller arteries (less than 100 microns) than in the larger ones (greater than or equal to 100 microns). Administration of smaller dose of nimodipine (0.01 mg/kg) also produced dilation of the pial vessels, although the effect was less remarkable in the smaller arteries. These data suggest that nimodipine might be useful in the treatment of the cerebral vasospasm after SAH. The mechanism underlying the action of nimodipine was discussed.

Animals↗
PubMed1981

Local cerebral blood flow values as estimated with diffusible tracers: validity of assumptions in normal and ischemic tissue.

A theoretical assessment is made of the validity of assumptions underlying the theory for estimating local cerebral blood flow with diffusible tracer in the tissue under normal and ischemic conditions. First, Kety's derivation of equations that have commonly been used for calculating local cerebral blood flow values is examined in order to define the problems and assumptions. Second, the brain:blood partition coefficient of diffusible tracer, lambda, and the diffusion-limited factor, m, under normal and ischemic conditions are reviewed. An examination of the literature suggested that contrary to common belief, lambda appears to change very little in ischemia if the tissue constituents remain unchanged, whereas m does change with ischemia if the diffusible tracer used is greatly diffusion-limited in the exchange between brain and blood. Even when a gas with an m value close to unity is used as the diffusible tracer, the prolonged mean transit time of blood through the ischemic tissue would make it difficult to maintain the exponential assumptions. As part of the ischemic tissue became infarcted, which is the case with most stroke patients, so the assumptions of homogeneous perfusion would become invalid. This inevitably renders it difficult to estimate local cerebral blood flow with diffusible tracer in ischemic tissue containing an infarcted mass.

Brain Ischemia↗