[Experimental study of cerebral protective effect on cerebral ischemia of various antioxidants and other agents. With special reference to the combined treatment of mannitol, vitamin E, dexamethasone and perfluorochemicals]

We have previously reported that the combined administration of mannitol and perfluorochemical blood substitutes is evidently effective in protecting the brain from cerebral ischemia. This experimental study was designed to develop more effective method in suppressing brain infarction than the combined treatment of mannitol and PFC. Using the "Canine model of complete ischemic brain regulated with a perfusion method" in which it is possible to control the degree of blood flow to a cerebral hemisphere via a perfusion pump, the effect of eight agents including six kinds as the free radical scavenger on cerebral ischemia was investigated. Eight agents were mannitol, vitamin E (Vit. E), dimethyl sulfoxide (DMSO), vitamin C, glycerol, nizofenone (Y-9179), dexamethasone (Dexa.) and suloctidil (MY-103). After pretreatment with each agent, blood flow was reduced via the pump to 1/10 of the normal state and 1 hour later, return to the normal state was allowed. Subsequent changes in EEG were observed and the effects of the drugs evaluated. In the control group, no recovery of electrical activity was seen, but in six groups among eight treated groups, i.e., treated with mannitol, Vit. E, DMSO, MY-103, Y-9179 and Dexa, gradual emergence of slow waves was observed. And more favorable effects were found when the combined administration of mannitol, Vit. E and Dexa was made in the same experimental schedule as compared with the single administration of each of these drugs. Furthermore in the animals administered with PFC in combination with mannitol, Vit. E and Dexa, flattening of electrical activity could not be seen throughout the period of severe ischemia. Moreover, the power of electrical activity recovered nearly to the preischemic state immediately after recirculation. Although the possible mechanisms are not yet completely clarified, the present results are thought to indicate that this new combination therapy utilizing PFC with mannitol, Vit. E and Dexa may be useful in the treatment of cerebral ischemia.

[Villaret's syndrome due to extra-cranial internal carotid aneurysm: a case report]

A 69 year-old male was admitted to our clinic with the chief complaint of hoarseness and difficulty in swallowing. These symptoms occurred about 5 months after penetrating neck injury. Neurological examination revealed right ninth to twelfth cranial nerves palsy and Horner's syndrome. Plain skull X-P demonstrated two broken pieces of glass below the right mastoid processus. The right carotid angiogram showed a 45 x 25 mm aneurysm originated from the right internal carotid artery just below the carotid canal. As the first operation, gradual occlusion of right internal carotid artery combined with the right STA-MCA anastomosis was performed. But two days after complete occlusion, left hemiparesis and pseudobulbar palsy appeared. Two months after such episode, aneurysm and the pieces of glass were removed. He discharged on foot with the improvement of the symptoms of lower cranial nerves. Villaret's syndrome caused by the traumatic aneurysm of extracranial internal carotid artery is rare. This case seems to be the first report in Japan.

Ultrastructure and some biologic properties of human oocytes and granulosa cells cultured in vitro

Of follicular oocytes with germinal vesicles, 79% resumed meiosis within 48 hours in modified Ham's F-10 medium for oocyte culture, and 59% of them reached the second-metaphase stage of meiosis. An increase in cortical granules and tubular aggregates and a decrease in the Golgi apparatus were observed during the maturation process. Scanning electron microscopy of the oocyte surface revealed a decrease in number and length of microvilli. Nuclear DNA contents diminished to approximately one-half, but cytoplasmic protein contents measured by cytofluorometry were unchanged after culture in spite of these structural changes. Insemination with washed spermatozoa resulted in fertilization of 5 of 43 zona-intact cultured oocytes. After removal of the zona, 6 of 17 cultured oocytes showed polyspermic penetration, although immature oocytes were not fertilized even after removal of the zona. Cultured granulosa cells secreted progesterone spontaneously, and its amount was correlated with follicular size. Ultrastructurally, mitochondria with laminar cristae, enlarged nuclei, dispersed Golgi apparatus, smooth endoplasmic reticulum, lipid droplets in the ooplasm, and granular cytoplasmic protrusions were observed on the oocyte surface.

Acute and chronic cardiocirculatory effects of oral prazosin in chronic refractory heart failure

The acute hemodynamic effects of oral prazosin were investigated in 7 patients with chronic refractory heart failure. A single dose of 1 to 3 mg prazosin produced a significant increase in cardiac index (+17.6%, p less than 0.01) associated with substantial decreases in pulmonary arterial diastolic pressure (-31.6%, p less than 0.02), systemic vascular resistance (-29.7%, p less than 0.01), and double product (-24.1%, p less than 0.02). Plasma renin activity was significantly elevated (+42.4%, p less than 0.02). These effects were found maximum at 2 hours and persisted for 8 hours. The chronic hemodynamic effects in 5 patients with chronic refractory heart failure were evaluated by administration of 1 to 2 mg prazosin 3 times daily for 8 weeks, and ventricular function was assessed by echocardiography and carotid pulse recording. All the patients showed improvement in the clinical symptoms of heart failure. Peripheral venous pressure decreased slightly (-12.5%). ET/PEP increased (+24.5%) without any significant changes in EF and mVcf. Plasma renin activity also slightly increased (+17.8%). Thus, prazosin possesses sustained nitroprusside-like actions, and is effective in the management of chronic congestive heart failure refractory to conventional therapy. While, further investigation is necessary to define the effect of prazosin on plasma renin activity.

Relationships between Chemical Structures of Crosslink Sites and Physical Properties of Vulcanized Rubbers. Part V. Analysis of Chemical Structures of Combined Sulfur in Crosslink Sites for Various EPDM Vulcanizates

Various EPDM vulcanizates with different chemical structures of crosslink sites, such as C—C, C—R—C and C—Sz—C linkage, were obtained by using a variety of curing agents. C—Sz—C linkage was separated into polysulfide linkage and monosulfide linkage by using the LiAlH4 method which was confirmed beforehand with model compounds. The relationships between the chemical structure of combined sulfur in the crosslink sites and the type of curing agents used were clarified. For example, the mole ratios of polysulfide linkage to all the combined sulfurs in the vulcanizates by using DCP—S8, TMTD, S8—TMTD and S8-zinc dimethyldithiocarbamate curing system were respectively 0.35, 0.25, 0.53 and 0.82 at 160° C for 45 minutes. But in DCP—S8 curing system considerable C—C linkages seemed to be formed in addition to the C—Sz—C linkage.

Relationships between Chemical Structures of Crosslink Sites and Physical Properties of Vulcanized Rubbers. Part VI. Oxidative Degradation of EPDM Vulcanizates

Relationship between the chemical structures of crosslinks and the degree of oxidative degradation of EPDM vulcanizates was studied by stress relaxation and oxygen absorption measurements. It was found that the vulcanizates having C—Sx—C crosslink showed slower stress relaxation than the vulcanizate having other crosslink structures, i.e., C—S—C, C—C, and C—R—C. It was thought that C—Sx—C bond would reduce the scission of the network in oxidative degradation, since some polysulfide compounds had the same effect of protecting scission as antioxidant. The similar results were obtained in oxygen absorption measurements. In the case of heat aging, the vulcanizate having C—Sx—C linkage increased in crosslinks during aging and the rate of crosslinking was equal to the rate of scission of the network in the early stages, but the vulcanizates having other types of crosslinks did not show such behavior.