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Biomedical subjects

H Yao

Publications and source records attributed to H Yao.

At least 199 records · Page 11Linked to original sources
PubMed1989

[Coronary bypass surgery in patients 70 years of age and older].

Twenty-six patients 70 years of age and older who underwent elective coronary artery bypass grafting were analyzed. These patients were compared with 76 patients under 70 years of age. The results obtained were as follows. The aged group had significantly greater incidences of preoperative pulmonary and renal complications. Preoperative cardiac function in the aged group was not different from that in the younger one. The incidence of left main trunk stenosis among the aged group (31%) was twice that in the younger one (15%). Then mean number of grafts was 3.0 in both groups. There were no significant differences in the operation time, anoxic arrest time, and extracorporeal circulation time between these two groups. Although the operative mortality rate in the aged group (11.5%) was higher than that (2.6%) in the younger one, the difference was not significant. Postoperative cerebral, respiratory and renal complications were more common in the aged group. However, the incidences of these complications were not different between these two groups. Surgical mortality and morbidity were improved in the latter half of the patients of the aged group, in whom only one operative death was observed and there was no life-threatening postoperative complication. Symptomatic improvements in survivors were remarkable. Thus, we conclude that coronary artery bypass grafting can be performed with acceptable risk in patients 70 years of age and older.

Age Factors↗
PubMed1988

Massive striatal dopamine release in acute cerebral ischemia in rats.

Extracellular dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and cerebral blood flow were simultaneously determined using in vivo brain dialysis and a hydrogen clearance method in the striatum of spontaneously hypertensive rats during ischemia and after recirculation. Massive striatal dopamine release was demonstrated in acutely induced ischemic brain.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1988

Impairment of cerebellar blood flow autoregulation during cerebral ischemia in spontaneously hypertensive rats.

Participation of the autonomic nervous system in cerebellar autoregulation during supratentorial cerebral ischemia induced by bilateral carotid ligation was studied using 23 spontaneously hypertensive rats. Cerebral and cerebellar blood flows measured by a hydrogen clearance method were evaluated under stepwise hemorrhagic hypotension before and 30 minutes after ligation and after a 30-minute recirculation period following 1 hour of ligation. alpha-Adrenergic blockade with phenoxybenzamine, beta-adrenergic blockade with propranolol, and muscarinic cholinergic blockade with atropine were selectively administered before ligation for inhibition of sympathetic and parasympathetic tone. Cerebral blood flow autoregulation was severely impaired during and after cerebral ischemia in each treatment group. During cerebral ischemia, cerebellar blood flow autoregulation was also significantly impaired in both the propranolol and atropine groups although it was better preserved in the phenoxybenzamine group. After recirculation, cerebellar blood flow autoregulation recovered almost to the normal range in the phenoxybenzamine and atropine groups but remained impaired in the propranolol group. Our results suggest that impaired cerebellar blood flow autoregulation in supratentorial cerebral ischemia is partly modulated by the alpha-adrenoceptor system, which is activated by hypertensive stimuli and cerebral ischemia, leading to vasoconstriction in the cerebellum.

Animals↗
PubMed1987

Importance of bilateral sympathetic innervation on cerebral blood flow autoregulation in the thalamus.

Effects of bilateral sympathetic innervation on the regulation of cerebral blood flow to the thalamus were examined in spontaneously hypertensive rats (SHR). The superior cervical ganglion was removed on one side or bilaterally, and blood flow in the thalamus was repeatedly measured with a hydrogen clearance technique during a stepwise increase in arterial pressure. Regional blood flow in the thalamus was unchanged following acute ganglionectomy: 55 +/- 6 ml/100 g/min in the intact rats and 56 +/- 4 in the denervated rats. Sympathectomy on one side neither had effects on the pressure-flow relationship nor on the blood pressure levels of upper limits of autoregulation in the ipsilateral thalamus. In contrast, bilateral sympathetic denervation impaired the autoregulatory function in the thalamus and the upper limits were significantly lower than those in intact rats: 206 +/- 8 vs 226 +/- 10 mm Hg, respectively (P less than 0.02). It is concluded that overlapping innervation of sympathetic nerves has an important role in regulation of blood flow to the thalamus during an acute rise in arterial pressure in SHR.

Adrenergic Fibers↗
PubMed1987

Mass fragmentographic determination of gamma-aminobutyric acid and glutamic acid in discrete amygdaloid nuclei of rat brain.

A mass fragmentographic method for the simultaneous quantification of gamma-aminobutyric acid (GABA) and glutamic acid is described. In a convenient one-step reaction, the two amino acids were derivatized with pentafluoropropionic anhydride and pentafluoropropanol. The derivatization products were stable for several days. The technique has been applied to the assay of GABA and Glu in five amygdaloid nuclei of the rat brain. The GABA level was high in the central and medial nuclei, whereas the Glu level was high in the lateral and basal nuclei. The regional distribution of GABA was different from that of Glu within the amygdaloid nuclei.

Amygdala↗
PubMed1987

Cerebrospinal fluid lactate in patients with hepatic encephalopathy.

Cerebrospinal fluid (CSF) lactate and pyruvate concentrations were determined in 16 patients with hepatic encephalopathy before and/or after treatment. CSF lactate was significantly increased to 1.92 +/- 0.11 mmol/l in hepatic encephalopathy before the treatment in comparison to 1.40 +/- 0.05 mmol/l in control subjects. In 9 of 11 patients with moderate or stage 2 encephalopathy, CSF lactate levels were below 2 mmol/l. In contrast, in 4 of 5 patients with stage 3-4 encephalopathy, CSF lactate levels were higher than 2 mmol/l. CSF lactate was decreased with the recovery of neurological symptoms by the treatment. These findings indicate that CSF lactate levels reflect the severity of metabolic impairment of the brain. Hypocapnia was frequently observed in these encephalopathic patients, and arterial PCO2 correlated inversely with CSF lactate and linearly with CSF HCO3-, suggesting that CSF lactic acidosis contributes to hyperventilation in hepatic encephalopathy. It is concluded from present results that metabolic disorder of neuronal cells might be one of the important factors for the development of hepatic encephalopathy.

Acid-Base Equilibrium↗
PubMed1986

Effect of chronic sympathetic denervation on cerebrovascular hypertrophy during the development of hypertension in rats.

The present study was designed to examine the trophic effect of sympathetic nerves on cerebrovascular hypertrophy in developmental hypertension. Unilateral superior cervical ganglionectomy was performed in spontaneously hypertensive rats at 4 weeks of age, and wall-to-lumen ratios of cerebral arteries were determined at 5 weeks, 2 months or 5 months after denervation. To estimate the thickness of the vessel wall, a freeze substitution technique was used for the preparation of cerebral arteries. Basal mean arterial blood pressure measured through cannulated femoral artery was 127 +/- 2, 146 +/- 7 and 168 +/- 6 mm Hg (mean +/- S.E.M.) at 9 weeks, 3 months and 6 months of age, respectively. The wall-to-lumen ratios in the denervated and innervated hemispheres were 0.124 +/- 0.004 and 0.129 +/- 0.005 at 9 weeks, 0.127 +/- 0.003 and 0.169 +/- 0.004 (P less than 0.02 vs denervated) at 3 months, and 0.194 +/- 0.007 and 0.222 +/- 0.006 (P less than 0.05 vs denervated) at 6 months. The effect of denervation was more significant in downstream vessels (diameter less than or equal to 100 microns) than larger ones. We conclude that wall-to-lumen ratio is correlated well with a rise in basal blood pressure, and chronic interruption of the sympathetic nerves attenuates normal occurrence of vascular hypertrophy during the development of hypertension.

Animals↗
PubMed1986

[Cavoatrial bypass in obstruction of the inferior vena cava in the hepatic portion through the posterior route of the hepatic caudate lobe].

In a 32-year-old Japanese female who had a history of Sjögren's syndrome, the obstruction of the inferior vena cava in the hepatic portion was found associated with Budd-Chiari syndrome. The obstruction of the inferior vena cava was about 6 cm in length by cavography. Cavoatrial bypass grafting was successfully performed with a 16 mm ring reinforced expanded polytetrafluoroethylene graft, which ran behind the caudate lobe of the liver and connected to the right atrium via right pleural cavity. This may be the first report of the posterior route of the hepatic caudate lobe in cavoatrial bypass grafting in Japanese and English literature.

Adult↗
PubMed1985

Neurogenic hypertension in the Guillain-Barré syndrome.

We report a case of Guillain-Barré syndrome associated with hypertension. The hypertension was related to glossopharyngeal and vagal nerve impairment. Plasma noradrenaline concentration (NA) and plasma renin activity (PRA) were elevated. The possible mechanism of the neurogenic hypertension produced by the sino-aortic denervation is discussed.

Adolescent↗
PubMed1983

Recurrent pheochromocytoma associated with glucagonoma. A case report.

We treated a hypertensive patient with recurrent pheochromocytoma (paraganglioma) associated with glucagonoma. No clinical symptom of glucagonoma was found and it could be detected only by a slight elevation of plasma immunoreactive glucagon (IRG) while the extirpated pancreatic tumor contained much IRG. This case could not be classified as either multiple endocrine neoplasia (MEN) type I or type II.

Adenoma, Islet Cell↗