Biomedical subjects

S Hiromatsu

Publications and source records attributed to S Hiromatsu.

7 recordsLinked to original sources

PubMed1995

Aortic dissection after aortic valve replacement. Report of a case with an aortocameral fistula.

A 58-year-old Japanese woman who had a history of aortic valve replacement for congenital bicuspid valve, was admitted for investigation of facial edema and of pulselessness of the right leg. Physical examination disclosed the patient suffering from a superior vena cava syndrome. On auscultation, a continuous murmur was heard at the left lower sternal border. Computed tomographic scans revealed aortic dissection extending from the ascending aorta to the bifurcation. Echocardiography showed an intimal flap in the dilated ascending aorta, but not abnormal blood flow from the aorta to the right atrium was detected. Cardiac catheterization and aortography, however, allowed a correct diagnosis of aortic dissection with fistula to the right atrium and with obstruction of the right common iliac artery. The patient received emergency aortic root replacement and reconstruction of the coronary arteries and then recovered uneventfully.

Aortic Dissection↗

PubMed1995

Total aortic replacement in a patient with mega aorta syndrome--a case report.

A 64-year-old woman without manifestations of Marfan syndrome was referred for the close investigation of a pulsatile abdominal mass. Computed tomographic scans and magnetic resonance images revealed aneurysmal dilatation of the entire aorta, including the ascending aorta and extending to the bifurcation of the aorta, as well as tortuousness of the thoracoabdominal and abdominal aorta. Digital subtraction angiography also showed aneurysmal dilatation of the entire aorta and trivial aortic regurgitation. However, aortic annular dilatation was not found by echocardiography or aortography. The entire aorta was replaced in two stages. First, graft replacement of the ascending aorta, except for the sinus segment, and the aortic arch was performed using an elephant trunk technique under hypothermic cardiopulmonary bypass with selective cerebral perfusion. Twelve weeks later, the remaining aorta, including the descending aorta and extending to the common iliac artery on the right side, and to the common femoral artery on the left side, was replaced with a partial cardiopulmonary bypass using femoral artery and vein cannulation. We believe that patients with mega aorta syndrome are best treated by total aortic replacement. The results in the present case indicate that the elephant trunk technique is useful for extensive aortic replacement in stages, and greatly facilitates the second stage operative procedures.

Aorta↗

PubMed1994

Endogenous acetylcholine concentrations in rat iris-ciliary body.

The technique of microwave irradiation, whereby enzymes are inactivated within milliseconds, was employed to accurately determine the in vivo acetylcholine (ACh) concentration in the iris-ciliary body (ICB). Rats were sacrificed by microwave irradiation at 9.5 kW at 2,450 MHz for 0.9 seconds. The eyes were enucleated, the ICBs isolated and 10 ICBs from 10 eyes were treated as one sample. ACh levels were determined using high performance liquid chromatography in an immobilized-enzyme reactor. Endogenous ACh levels in the rat ICB were 58.8 +/- 5.0 nmoles (8.58 +/- 0.73 micrograms) per gram tissue protein (mean +/- SE, 9 samples). A single instillation of 5 microliters of 0.05% atropine in one eye of an animal lowered the ACh level in the ICB of the eye (P < 0.02).

Acetylcholine↗

PubMed1994

Endogenous catecholamine concentrations in rat iris-ciliary body.

Endogenous catecholamine concentrations in the rat iris-ciliary body (ICB) were determined using the technique of microwave irradiation, whereby enzymes are inactivated within milliseconds, and high performance liquid chromatography. Rats were sacrificed by microwave irradiation at 9.5 kW at 2450 MHz for 0.9 seconds. The eyes were enucleated, the ICBs isolated, and 10 ICBs from 10 eyes were treated as one sample. Endogenous norepinephrine levels in the rat ICB were 19.5 +/- 2.3 nmol per gram tissue protein (mean +/- SE, 7 samples), while endogenous dopamine levels were 3.2 +/- 0.2 nmol. Epinephrine could not be detected. A single instillation of 5 microliters of 0.05% apraclonidine, an alpha-2 agonist, in one eye of an animal raised the NE level in the ICB of the treated eye by 8% compared to that in the untreated fellow eye (P < 0.05).

Adrenergic alpha-Agonists↗

PubMed1992

Partial brachiocephalic perfusion under hypothermic cardiopulmonary bypass. An experimental study.

We studied electrophysiological, oxygen metabolic, and histological variables in dogs to establish the reliability and safety of partial brachiocephalic perfusion (PBP) under hypothermic cardiopulmonary bypass (CPB) at 23 degrees-25 degrees C. Sixteen mongrel dogs were divided into two groups. Six (control group) underwent typical hypothermic CPB for 90 min, and 10 (PBP group) underwent PBP under hypothermic CPB for 90 min. During core cooling on the CPB, a progressive reduction in voltage and slowing of frequency of the electroencephalogram (EEG) was observed. At around 23 degrees C nasopharyngeal temperature the tracing became almost flat and remained so throughout the hypothermic CPB or the PBP under hypothermic CPB. Consistent recovery of the EEG was, however, observed during the period of rewarming on the CPB, and the voltage and frequency of the EEG recovered to control levels on weaning off CPB at 36 degrees C in both groups. In the PBP group, the cerebral arteriovenous oxygen (AVO2) difference was 12.4 +/- 4.0 vol% before beginning the CPB, and it was 5.6 +/- 2.7, 5.7 +/- 3.1, 5.4 +/- 3.3, and 4.9 +/- 2.9 vol% at 10, 30, 60, and 90 min respectively after commencement of the PBP under hypothermic CPB. The cerebral AVO2 difference measured 10 min after commencement of the PBP was significantly less than that in the control group (P less than 0.05), but otherwise there were no significant differences between cerebral AVO2 differences in the two groups. Concentration of serum creatine kinase-BB (CK-BB) gradually increased in proportion to the duration of CPB in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

[Effects of alpha 2-agonist apraclonidine on norepinephrine levels in the rat iris-ciliary body].

In an attempt to estimate the in vivo catecholamine level in rat iris-ciliary body, animals were sacrificed by microwave irradiation which rapidly inactivates metabolic enzymes. Catecholamine levels in the iris-ciliary body were determined by high-performance liquid chromatography with electrochemical detection. The norepinephrine level in rat iris-ciliary body per gram tissue protein was 3.56 +/- 0.22 micrograms/g (21.1 +/- 1.3 nmol/g)(mean +/- SEM, n = 7). Neither dopamine nor epinephrine were detected. A single instillation of 5 microliters of an 0.05% apraclonidine (alpha 2-agonist) to one eye of a rat increased the norepinephrine level in the iris-ciliary body by 7.7% one hour after administration (p less than 0.05).

Adrenergic alpha-Agonists↗

PubMed1992

[Effects of atropine on acetylcholine levels in the rat iris-ciliary body].

In an attempt to estimate the in vivo acetylcholine level in rat iris-ciliary body, animals were sacrificed by microwave irradiation which rapidly inactivates metabolic enzymes. Acetylcholine levels in the iris-ciliary body were determined by high-performance liquid chromatography with electrochemical detection. The acetylcholine level in rat iris-ciliary body per gram tissue protein was 58.8 +/- 5.0 nmol/g (mean +/- SEM, n = 9). A single instillation of 5 microliters of an 0.05% atropine to one eye of a rat decreased acetylcholine level in the iris-ciliary body by 17% half an hour after administration (p less than 0.02).

Acetylcholine↗