Biomedical subjects
Publications and source records attributed to Y Yatabe.
Dilevalol, an alpha- and beta-blocking agent, has been evaluated in two patients with pheochromocytoma. Dilevalol could be a useful agent for the treatment of pheochromocytoma, especially for the adrenaline-dominant type.
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Effect of diazepam on the AV nodal conductivity was studied using a direct perfusion technique of the canine AV node artery in situ. As compared to acetylcholine which induced a rapid onset of third degree AV block with prompt recovery, diazepam injected into the AV node artery in doses from 300 micrograms to 3 mg elicited first to third degree AV blocks of longer duration following gradual prolongation of PR interval. The response was not affected by bilateral vagotomy and sympathectomy. Pretreatment of the AV node with hexamethonium or atropine also failed to modify the diazepam-induced AV blocks. Thus, diazepam seemed to suppress conductivity of the AV node by a direct action. The AV nodal tachycardia induced by infusion of norepinephrine was readily antagonized by a single injection of diazepam, but norepinephrine failed to reverse the AV block induced by diazepam infusion.
Mechanism for induction of the positive chronotropic effect of ketamine was studied in vivo using a selective perfusion technique of the canine SA node artery. In the reserpinized dogs in which tyramine responsiveness could be restored with norepinephrine, an injection of ketamine induced no sinus acceleration, while its prior administration to norepinephrine suppressed the response to tyramine. In the tetrodotoxin treated preparation in which the effect of electrical stimulation of the vagus and the stellate ganglion was abolished, tyramine produced an increase of sinus rate as usual, but the induction of sinus tachycardia by cocaine and ketamine was completely blocked. The results indicated that the positive chronotropic response of the SA node to ketamine might be induced by an inhibition of the norepinephrine uptake at the adrenergic nerve endings in a cocaine-like manner.
In an attempt to clarify the mechanism of shock in dental patients, the effects on the heart rate of the injection of an anesthetic agent into the oral mucosa were studied. The heart rates of the subjects decreased by an average of 12.6% during infiltration anesthesia, which was greater than that induced by the mandibular block or breathholding. The response was completely blocked by general anesthesia and partially blocked by inhalation of nitrous oxide and oxygen or previous administration of atropine, indicating the possible participation of trigeminal-vagal reflex in producing these changes of heart rate.
Effect of propanidid on the pacemaker activity of the SA node was investigated in anesthetized dogs by injecting 30 microgram to 3 mg into the SA node artery in a single dose in a period of 4 sec. The doses of more than 100 microgram usually induced a negative chronotropic response. The injection of more than 1 mg frequently caused a sinus arrest followed by AV nodal rhythm. The initial sinus rhythm, however, was restored within 2 min after the propanidid administration. Its negative chronotropic response was not altered by pretreatment with atropine which completely blocked the action of acetylcholine. Bilateral vagotomy also did not affect the response induced by propanidid. A control solution or histamine failed to cause such a depressant effect on the SA node as observed after the propanidid injection. Thus, we conclude that propanidid supresses the SA nodal activity by a direct local action.
Effect of ketamine on the SA node of the dog heart was studied in vivo using a selective perfusion technique of the SA node artery. Injections of ketamine in doses from 100 microgram to 3 mg into the artery produced a depression of the SA nodal activity by a direct action. This depression was followed by the sudden appearance of a stimulatory phase. Bilateral vagotomy and sympathectomy or prior administration of a ganglion blocker failed to inhibit the occurrence of the ketamine-induced tachycardia, while it was completely abolished in the reserpinized dogs or by a prior injection of a beta-blocking agent into the SA node artery. This may indicate that an activation of the peripheral adrenergic mechanism plays an important role in the induction of the excitatory effect of ketamine injected in the SA node artery.
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PURPOSE: To compare polymerase chain reaction (PCR) results with histological, immunohistochemical, and clinical findings to understand the nature of ocular adnexal lymphoid proliferation. METHODS: We examined 20 cases (21 specimens) of ocular adnexal lymphoid proliferation, using histological, immunohistochemical, and molecular genetic methods. The latter two types of experiments were performed to examine the light chain restriction of immunoglobulin using the peroxidase-antiperoxidase method, and the clonality of immunoglobulin heavy chains using the PCR method. RESULTS: Although in 8 cases it could not be determined morphologically whether the tumors were neoplastic or not, clonality was revealed in 1 case by immunohistochemistry and in 4 cases by PCR. Two cases showed disparate results between immunohistochemistry and PCR, probably due to somatic mutation of the framework region of the immunoglobulin heavy chain gene. CONCLUSION: Examination using these methods contributes to a better understanding of the nature of the ocular adnexal lymphoid proliferation. Furthermore, the immunoglobulin gene PCR method is very useful in practice for examination of specimens, as it can be used with formalin-fixed and paraffin-embedded specimens.
We report a 26-year-old woman with cellular hemangioendothelioma that may be the third case diagnosed as cerebellar hemangioendothelioma. The tumor was composed of numerous vascular channels lined by endothelial cells and aggregates of large round endothelial cells. Transitional cells were also present. The large round cells were positive for CD34 and vimentin in their abundant cytoplasm that contained 1 or some red blood cells, revealing intracytoplasmic lumina. The patient remains free of disease over 5 years after tumor resection.