Shotaro Yoneda

Carotid lesions detected by b mode ultrasonography in takayasu's arteritis macaroni sign as an indicator of the disease

Twenty-three patients were studied to evaluate the clinical usefulness of high resolution B-mode ultrasonography in the detection of carotid lesions in patients with Takayasus arteritis. In each patient the carotid arteries were examined using both B-mode ultrasonography (midfrequency of 7.5 MHz) and contrast angiography. In 19 of 23 patients, B-mode ultrasonography clearly demonstrated the characteristic circumferential arterial wall thickening of either one or both sides of the common carotid arteries as a macaroni-like, diffusely thickened intima-media complex. Conversely, contrast angiography demonstrated carotid lesions in only 13 of 23 patients. These results clearly show that B-mode ultrasonography is quite sensitive and superior in the detection of the characteristic thick intima-media complex of the common carotid artery in patients with Takayasus arteritis, when compared with contrast angiography that is usually used for the definitive diagnosis of this disease.

Efficacy of echo-doppler examination for the evaluation of renovascular disease

The accuracy of the diagnosis of renal artery stenosis using noninvasive echo-Doppler velocimetry was compared with that of angiography in 40 renal arteries. The duplex-Doppler signals were detected through the muscle of the back (the translumbar approach). Renal artery stenosis was diagnosed by three objectively defined Doppler parameters, the acceleration index (AI), the acceleration time (AT), and the acceleration time ratio (ATR). The normal range obtained on 11 control subjects was defined as AI greater than or equal to 3.78, AT less than or equal to 0.07 s, and ATR less than or equal to 1.35. High technological success (98%) was obtained using the translumbar approach. In comparison with angiography (cases of significant stenosis), the accuracy of the echo-Doppler method using the criteria of the AI was 95%, the sensitivity was 100%, and the specificity was 93%. This noninvasive method may be one of the most accurate screening methods for diagnosing significant renal artery stenosis.

Two distinct calcitonin gene-related peptide-containing peripheral nervous systems: Distribution and quantitative differences between the iris and cerebral artery with special reference to substance P

The present study first shows that calcitonin gene-related peptide(CGRP)-like immunoreactive (CGRPI) nerve fibers in the cerebral arteries contained substance P (SP) and originated from small- to medium-sized CGRPI cells exhibiting SP immunoreactivity (SPI) in the trigeminal ganglion. The iris contained CGRPI/SPI-costorage nerve fibers and many CGRPI fibers lacking SPI. These fibers originated from large CGRPI cells lacking SPI in the trigeminal ganglion. The heterogenous subpopulations of CGRPI fibers in the iris suggest that CGRP is involved in a variety of functions in this structure.

Overall distribution of vasoactive intestinal polypeptide-containing nerves on the wall of cerebral arteries: An immunohistochemical study using whole-mounts

The overall distribution of vasoactive intestinal polypeptide (VIP)-like immunoreactivity on the wall of the cerebral arteries, including its 3-dimensional profile, was investigated by means of the indirect immunofluorescence method using flat-mounts. VIP-immunoreactive fibers run spirally on the wall of the cerebral arteries. On the wall of the large arteries, such as the vertebral artery, basilar artery, internal carotid artery, within and/or without the circle of Willis, posterior and anterior communicating arteries, proximal parts of anterior, mid and posterior cerebral arteries, these fibers are richly distributed and show a dense grid-like appearance. The highest density was identified on the wall of the anterior cerebral artery, internal carotid artery and anterior communicating artery, while the lowest density was on the posterior communicating artery. On the other hand, on the walls of the branches of these arteries or along distal parts of the anterior, mid and posterior cerebral arteries, the number of VIP-immunoreactive fibers decreased markedly.

Effects of Hematocrit Variations on Cerebral Blood Flow and Oxygen Transport in Ischemic Cerebrovascular Disease

The contribution of hematocrit (Ht) changes on cerebral blood flow (CBF) and brain oxygenation in ischemic cerebrovascular disease is still controversial. In the present study, effects of Ht variations on CBF and oxygen delivery were investigated in patients with ischemic cerebrovascular disease. CBF was measured by the Xe-133 intracarotid injection method in 27 patients, whose diagnoses included completed stroke, reversible ischemic neurological deficit, and transient ischemic attack. Ht values in the patients ranged from 31 to 53%. There was a significant inverse correlation between CBF and Ht in these Ht ranges. Oxygen delivery, i.e., the product of arterial oxygen content and CBF, increased with Ht elevation and reached the maximum level in the Ht range of 40–45% and then declined. The CBF-Ht and oxygen transport-Ht relations observed in our study were similar to those in the glass-tube model studies by other workers rather than to those in intact animal experiments. From these results, it is conceivable that in ischemic cerebrovascular disease, the vasomotor adjustment was impaired in such a manner that the relations among Ht, CBF, and oxygen delivery were different from those in healthy subjects. Further, an “optimal hematocrit” for brain oxygenation was also discussed.

Origins and distribution of calcitonin gene-related peptide-containing nerves in the wall of the cerebral arteries of the guinea pig with special reference to the coexistence with substance P

The origins and overall distribution of calcitonin gene-related peptide-like immunoreactivity (CGRPI) in the wall of the cerebral arteries were investigated in the guinea pig by using whole-mounts. Two types of CGRPI fibers were seen; one forming dense fiber bands, located among the periadventitial nerves, and the other forming a meshwork. CGRPI fibers in the periadventitial nerves often leave these nerves to form a meshwork, of a density that varies according to the diameter or location of the blood vessel. The present study showed that CGRPI fibers in the walls of the carotid arterial system originated from the trigeminal ganglion, and those in the vertebrobasilar arterial system from other origins besides the trigeminal ganglion. We also examined the coexistence of this peptide with substance P-like immunoreactive (SPI) structures in a single neuron system. Double staining immunocytochemistry showed that the patterns of the running of CGRPI and SPI fibers in the wall of the cerebral arteries were similar, and this method also demonstrated the presence of neurons containing both CGRPI and SPI structures in single cells of the trigeminal ganglion, which is the major origin of these fibers in the cerebral arteries.

To-and-Fro Movement and External Escape of Carotid Arterial Blood in Brain Death Cases. A Doppler Ultrasonic Study

In brain death cases who showed nonfilling phenomena in the internal carotid angiograms, the blood flow velocity patterns of the common carotid arteries were characterized by involvement of a single systolic peak and a marked reverse flow component which had never been observed in healthy subjects. The individuality of each blood flow velocity pattern in the common, internal and external carotid arteries was made clear by placing the transducer in contact with the respective artery in a certain case. The Doppler signal from the internal carotid artery involving a signal from a reverse flow was slightly detectable, even if the blood pressure was elevated by norepinephrine infusion and the external carotid artery was temporarily compressed. The blood flow velocity pattern of the external carotid artery was similar to the pattern of the common carotid artery. The peculiar flow pattern indicates that a brain death case has a to-and-fro movement in the internal carotid blood flow and an external carotid escape of common carotid arterial blood.

Echo-Doppler velocimeter in the diagnosis of hypertensive patients: the renal artery Doppler technique

The renal blood flow velocity characteristics in 8 normal controls, 19 essential hypertensive patients and 8 hypertensive patients with renovascular disease were evaluated using echo-Doppler velocimetry. Two different approaches for ultrasonic detection of the renal artery, the translumbar and the transabdominal approach, were used. Renal Doppler sonograms were analyzed by measuring the acceleration index and the peak-systolic frequency/end-diastolic frequency (S/D) ratio. Renovascular patients who required surgery were examined before and after angioplasty. Doppler signals could be detected in all 35 subjects by using the translumbar approach. The acceleration index of the affected renal arteries significantly correlated to the percent stenosis of the renal artery determined by angiography. The acceleration index in the affected renal artery was improved by surgical treatment. The S/D ratio in essential hypertensives was significantly higher than that in the normal controls. There was a significant inverse correlation between the S/D ratio and creatinine clearance. Echo-Doppler velocimetry is considered to be useful in the diagnosis of renovascular disease and also in the evaluation of abnormalities of renal vascular resistance in hypertensive patients.

Differential Effect of Cerebral Ischemia on Monoamine Content of Discrete Brain Regions of the Mongolian Gerbil (Meriones unguiculatus)

Abstract: The effect of bilateral cerebral ischemia on noradrenaline, dopamine, and serotonin concentrations in six brain regions (i.e., the cerebral cortex, striatum, hippocampus, midbrain‐diencephalon, cerebellum, and pons‐medulla oblongata) was examined in the gerbil stroke model. The relative changes in regional cerebral blood flow after bilateral common carotid occlusion were also assessed using the radioactive microsphere technique. At 1 h after bilateral carotid occlusion, a significant decrease of monoamine concentration was observed in the cerebral cortex, striatum, hippocampus, and midbrain‐diencephalon whereas no significant change was detected in the cerebellum and pons‐medulla oblongata. The fall in NA content was most prominent in the cerebral cortex and hippocampus and percentage reductions of dopamine and serotonin were greatest in the striatum and cerebral cortex, respectively. These results suggest that the monoamine neurons in various brain regions might have different vulnerabilities to ischemic insult and show no evidence of transtentorial diaschisis.

The effect of the calcium antagonist nimodipine on the gerbil model of experimental cerebral ischemia.

The gerbil model was used to assess the therapeutic effects of the calcium antagonist nimodipine on cerebral ischemia. Transient cerebral ischemia was produced in each gerbil by bilateral common carotid occlusion of 10-, 15- or 20-min duration. Nimodipine (0.01 or 0.1 mg/kg) was administered intraperitoneally just before the carotid occlusion or 10-30 min after the removal of the arterial clips. Morbidity of each animal was evaluated using the stroke index, and the sum of stroke indices was calculated for evaluating the overall morbidity during a particular period of reperfusion. Mortality was observed for 24 hours after clip removal. Although, depending on the timing of the drug administration, the low-dose (0.01 mg/kg) nimodipine worsened the morbidity in the gerbils with 10-min ischemia, the high-dose (0.1 mg/kg) of the drug had a clear beneficial effect on the mortality associated with cerebral ischemia. These results are considered worthwhile for further trials to assess the usefulness of nimodipine as a therapeutic agent in the management of the acute ischemic stroke.