Contractile effects of hemoglobin-free human cerebrospinal fluid on isolated porcine cerebral arteries

To elucidate the mechanism involved in the cerebral vascular spasm following subarachnoid hemorrhage (SAH), the effects of the cerebrospinal fluid (CSF) obtained from the SAH patients on the resting tension and its influence on the contractile responses to various vasoactive agents and to hypoxia were investigated in isolated porcine cerebral arteries. All the CSFs containing hemoglobin (Hb) produced contraction and some Hb-free CSFs also elicited contraction. When the Hb-free CSF was separated by microfilter, the filtrate of < 30,000 MW did not produce contraction, while the fraction above 30,000 MW elicited more marked contractile responses than the unfractionated CSF. The CSF contraction was significantly attenuated in the presence of indomethacin or nimodipine, whereas the contractions induced by KCl, prostaglandin F2alpha (PGF2alpha), or endothelin-1 (ET-1) were not affected by the CSF pretreatment. However, the contractile responses induced by 5-hydroxytryptamine (5-HT) and phenylephrine (PE) were markedly potentiated by the pretreatment. Hypoxia-induced vasoconstriction was significantly potentiated by the pretreatment with either unfractionated CSF or the CSF fraction of above 30,000 MW. These results suggest that unknown vasocontractile substance(s) exists in the Hb-free CSF and that the substance, with its MW above 30,000, is activated by hypoxia and acts synergistically with 5-HT and PE, and that extracellular calcium influx and cyclooxygenase are also involved in the cerebral vasoconstrictory effect of Hb-free CSF.

Pressor Effect of Intracerebroventricular 4-Aminopyridine on the Systemic Arterial Pressure in the Rabbit

A K+-channel blocker, 4-aminopyridine(4-AP) increases neurotransmitter release from motor nerve terminals and has been shown to restore neuromuscular transmission in the myasthenic syndrome. It has been reported that the intravenous injection of 4-AP in the myasthenic patients caused many central adverse effects including anxiety and restlessness, but did not affect the blood pressure. The aim of this study was to observe the effect of intracerebroventricularly administered 4-AP on the blood pressure and to elucidate the mechanism of the action in urethane-anesthetized rabbits. Intracerebroventricular(icv) 4-AP produced pressor effects in a dose-dependent fashion, but intravenous(iv) 4-AP of the same dose did not altered the blood pressure. Tetraethylammonium, a K+-channel blocker which differs from 4-AP structurally, had little effect on the blood pressure, but 3,4-diaminopyridine, another derivative of the aminopyridine, produced pressor effect similar to 4-AP. The pressor effect of icv 4-AP was not affected by the treatment with iv phenoxybenzamine and chlorisondamine, and in bilateral adrenalectomized rabbits. These results suggest that the 4-AP pressor effect is not related to the periphral sympathetic nerve nor adrenal gland. The pretreatment with icv phentolamine and prazosin did not altered the 4-AP pressor. However, the icv 4-AP pressor effect was significantly attenuated by the treatment with icv yohimbine, and significantly potentiated by the treatment with icv clonidine. The treatment with icv diltiazem markedly inhibited the icv 4-AP pressor effect. It is concluded that 4-AP-sensitive K+-channels in rabbit brain might play a role in the regulation of blood pressure and that the 4-AP pressor effect is closely related to the central alpha2-adrenoceptors and L-type calcium channels.

A Case of Retained Abdominal Pregnancy / 대한산부인과학회잡지

Intra-abdominal pregnancy is uncommon occurrence, constituting only 1% of all ectopic pregnancy. It is usually the result of a tubal or ovarian pregnancy that has aborted or ruptured into the peritoneal cavity. However, the complications of abdominal pregnancy can be devastating. Premature placental separation with massive hemorrhage, hypofibrinogenemia following fetal demise, and suppuration and abscess formation lead to producing maternal health risk. A perinatal mortality and maternal mortality were 85-95% and 0.5-6% respect-ively, from the world literature. Optimal obstetrical care requires early diagnosis and prompt surgical intervention. Recently, a patient presented to the St.Francisco general Hospital with a retained abdominal pregnancy of 6 years duration without complications, as discussed below.