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Biomedical subjects

R Mori

Publications and source records attributed to R Mori.

258 records · Page 15Linked to original sources
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Reversal of adrenaline-induced contraction in the rabbit pulmonary artery by clonidine.

Characterization of clonidine which reversed the adrenaline-induced contractions was assessed using the rabbit pulmonary arterial segment. Clonidine in high concentrations (10(-5)-10(-4) mol/l) contracted this vascular tissue. Nevertheless, an adrenaline (3 X 10(-6)mol/l)-induced contraction, which can be markedly depressed by phentolamine, was reversed to relaxation by pre-addition of 3 X 10(-5)mol/l clonidine. This reversal was abolished by 10(-5) mol/l propranolol, a beta-adrenoceptor antagonist. The cumulative concentration-contraction curve for adrenaline was shifted to the right by 10(-5) mol/l clonidine without further alteration at 10(-4) mol/l, suggesting a partial agonistic feature of clonidine for alpha-adrenoceptors. Contractions evoked by 5 X 10(-5) mol/l clonidine alone were effectively reduced by prazosin (IC50 = 1.7 X 10(-7) mol/l) or yohimbine, (IC50 = 3.3 X 10(-5) mol/l) and those by phenylephrine (10(-5) mol/l) were suppressed as well (prazosin, IC50 = 3.4 X 10(-8) mol/l; yohimbine, IC50 = 5.0 X 10(-6) mol/l). However, the depolarization-induced contractions with 30 mmol/l KCl were virtually unaltered by both antagonists. These results suggest that the reversal action of clonidine on the adrenaline-induced contraction is primarily mediated by a partial agonistic property for postsynaptic alpha 1-adrenoceptors.

Animals↗
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Cardiovascular effects of brovincamine and possible mechanisms involved.

Cardiovascular effects of brovincamine (BV) and possible modes of action were studied in dogs, rabbits and guinea-pigs. In pentobarbitone-anaesthetized dogs, intravenous administration of BV (1.6-12.8 mg/kg) induced a dose-dependent decrease of blood pressure and heart rate, a slight and transient stimulation of respiration, and a prolongation of the R-R interval in ECG without changes of wave pattern. In the isolated atria of guinea-pigs, BV showed no effect at 10(-7) and 10(-6) g/ml, but dose-dependently inhibited both myocardial contractile force and heart rate at the higher concentrations of 10(-5) and 10(-4) g/ml. In pentobarbitone-anaesthetized dogs, BV (0.1-1.6 mg/kg) administered to the vertebral or carotid artery dose-dependently increased the blood flow in the respective artery. Intravenous administration of BV (0.8-12.8 mg/kg) also exhibited a dose-dependent increase of the vertebral and carotid blood flow, but the increase was a little reduced at the higher dose of 12.8 mg/kg, probably resulting from marked hypotension and negative chronotropism. Intravenous administration of BV at 6.4 mg/kg induced a marked increase of the coronary flow, a slight increase of the renal flow and a slight decrease of the femoral flow. 11-Bromovincaminic acid (BVA, 0.1, 0.2 mg/kg), a major metabolite of BV, given intravenously or to the internal carotid artery, did not exert actions on the blood pressure, heart rate and carotid blood flow, implying that it is an inactive metabolite. In rabbit pulmonary arterial strips, BV showed no influence on effects of noradrenaline and adenosine but inhibited KCl-induced contracture. This inhibitory effect of BV, but not papaverine, was antagonized by an increase of external Ca2+ concentration. In conclusion, BV rather selectively increases the cranial and coronary blood flow. The vasodilative effects of BV seem to involve an inhibition of depolarization dependent Ca2+ slow channel. A major metabolite of BV, BVA, is inactive.

Animals↗
PubMedDate not supplied

Preoperative factors influencing visual outcome following surgical excision of subfoveal choroidal.

PURPOSE: To evaluate long-term visual acuity outcomes and the influences of various preoperative factors on visual outcome in patients undergoing surgical removal of choroidal neovascular neovascularization (CNV) caused by age-related macular degeneration (ARMD). METHODS: The authors studied 146 eyes of 146 patients who were followed for at least 1 year after surgical excision of CNV associated with ARMD. Surgical indications included subfoveal active CNV localized mainly above the retinal pigment epithelium (RPE) and a standard Japanese decimal visual acuity of 0.3 or worse. CNV above the RPE was diagnosed by fluorescein angiography, indocyanine green angiography, and optical coherence tomography. CNVs were divided into completely classic CNV or mainly classic CNV. The relationships of the post-operative logarithm of the minimum angle of resolution (logMAR) visual acuity with preoperative logMAR visual acuity, the shortest distance from the center of the foveal avascular zone to the CNV margin, CNV size, and age were analyzed. RESULTS: Final logMAR visual acuity was improved (defined as a logMAR visual acuity increase of 0.2 or more) in 78 eyes (54%), stable in 47 (32%), and worsened in 21 (14%). Stepwise regression identified CNV size as a significant factor influencing final logMAR visual acuity (R2 = 0.213, p<0.0001), while preoperative logMAR visual acuity, shortest distance from the center of the foveal avascular zone to the CNV margin, and age showed no significant correlation with final logMAR visual acuity. Surgical complications included retinal detachment in six eyes (4%), subretinal hematoma in four eyes (2%), macular hole in three (2%), and proliferative vitreoretinopathy in two (1%). CNV recurred postoperatively in 18 eyes (12%). In 92 eyes with completely classic CNV, visual acuity was improved in 57 (62%), stable in 27 (29%), and worsened in 8 (9%). In 54 eyes with mainly classic CNV, visual acuity was improved in 21(39%), stable in 20 (37%), and worsened in 13 (24%). CONCLUSIONS: Surgical excision of CNV for ARMD was effective for completely classic CNV, and better postoperative visual acuity was achieved in cases of small CNV. Given the fact that photodynamic therapy (PDT) has only been used in Japan since 2004, future study should compare PDT and surgical excision in Japanese subjects for relative merits against surgical risk and postoperative complications, to define indications for PDT and surgical excision.

Aged↗
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Treatment of disseminated herpes zoster in six severely immunocompromised patients: acyclovir and vidarabine.

We treated 6 patients with disseminated herpes zoster (D-H-Z) and in a severely immunocompromised condition. Three were effectively treated with 15 mg/kg/day of acyclovir. Ten mg/kg/day of vidarabine alone was given to two patients, but without positive effects. In two patients, acyclovir was effective in limiting the progression of the lesions. The skin lesions looked like a "stitch" on vesicles, thereby suggesting that the "stitch like appearance" may be a useful marker to identify the resistance to acyclovir treatment. In one patient, acyclovir was given for 58 days, but with limited effectiveness. When vidarabine was given in addition to acyclovir, the lesions dramatically disappeared. These findings suggest that acyclovir is superior to vidarabine for treating D-H-Z and the combination therapy with acyclovir and vidarabine should be considered for prescription for patients with D-H-Z, if acyclovir alone is not completely effective.

Acyclovir↗