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Biomedical subjects

H Akagi

Publications and source records attributed to H Akagi.

At least 109 records · Page 6Linked to original sources
PubMed1989

[Staged repair of type A interrupted aortic arch using the Blalock-Park method in infancy: development of the reconstructed aortic arch].

Three infants with type A interrupted aortic arch, VSD and PDA underwent staged operation. Aortic arch reconstruction with Blalock-Park's method, PDA division, and PA banding were performed as the first operation. Subsequently all patients were underwent the second operation, consisting of VSD closure and PA debanding, and are doing well now. Pressure gradient at the anastomosis site, the diameters of the anastomosis site and the left subclavian artery, and the diameter ratios of the anastomosis site and the left subclavian artery to the ascending aorta were evaluated after the first and second operation. Two patients with good size of the left subclavian artery at the first operation showed excellent growth of the reconstructed aortic arch and trivial pressure gradient at the anastomosis site. The other patient, whose preoperative left subclavian artery was small (2.5 mm in diameter) resulted in residual stenosis at the anastomosis site. The development of the left subclavian artery was satisfactory in all patients. These data suggest that the aortic arch reconstructed with Blalock-Park's method can grow if the diameter of the anastomosis site has adequate size at the first operation.

Aorta, Thoracic↗
PubMed1989

Efficacy of coronary artery bypass surgery with gastroepiploic artery. Assessment with thallium 201 myocardial scintigraphy.

This study describes the efficacy of the right gastroepiploic artery (GEA) as graft material for coronary artery bypass grafting (CABG) as assessed by exercise thallium 201 myocardial scintigraphy in eight patients (age, 59.4 +/- 9.35 years [mean +/- SD]) who underwent CABG with the GEA graft in the past 2 years. Planar and single-photon-emission computed tomographic (SPECT) images were obtained during and 3 hours after exercise. Planar images were evaluated quantitatively with the percentile-washout method, and SPECT images were evaluated qualitatively with a bull's-eye, polar-coordinate map. All patients had triple-vessel disease, and in situ GEAs were anastomosed to the right coronary artery in seven patients and to the left anterior descending coronary artery in one. The internal mammary artery graft was concomitantly used in all patients. The mean number of grafts per patient was 3.0 (range, 2-4). Preoperative exercise testing could not be performed in two patients because of emergency operation. By qualitative assessment with the polar-coordinate map, four patients showed improvement, one did not show any change, and one became worse due to perioperative myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Expression of glycine and other amino acid receptors by rat spinal cord mRNA in Xenopus oocytes.

Xenopus oocytes were injected with mRNA from adult or neonatal rat spinal cord, or from adult cerebral cortex, and examined electrophysiologically to measure currents elicited by various receptor agonists. The mRNAs induced the oocytes to acquire similar types of amino acid receptors, albeit with different potencies. In oocytes injected with adult cord mRNA the responses to kainate and gamma-aminobutyrate were much smaller, whilst the currents elicited by glycine and beta-alanine were markedly larger, than those in oocytes injected with cortex mRNA. For these receptors, the expressional potency of neonatal spinal cord mRNA is similar to that of the adult cord mRNA, except for a lower sensitivity to beta-alanine.

Amino Acids↗
PubMed1988

Heterogeneity of glycine receptors and their messenger RNAs in rat brain and spinal cord.

Messenger RNAs isolated from adult or newborn rat spinal cord were fractionated in a sucrose gradient. The fractions were injected into Xenopus oocytes to determine their potencies for expression of glycine receptors (GlyRs), which were then examined electrophysiologically. The sedimentation profiles disclosed two classes of GlyR mRNAs, one heavy and the other light. The adult spinal cord was rich in heavy GlyR mRNA, whereas the light GlyR mRNA was more abundant in neonatal spinal cord and in adult cerebral cortex. Glycine receptors encoded by heavy and light mRNAs of adult spinal cord showed some electrophysiological differences. Thus there are two types of GlyRs encoded by mRNAs of different sizes, and the expression of these mRNAs is developmentally regulated. A tissue- and age-dependent distribution of heterogeneous GlyR mRNAs may imply diverse roles of the GlyRs in neuronal function in the central nervous system.

Animals↗
PubMed1988

Identification of two taurine receptor subtypes on the primary afferent terminal of frog spinal cord.

1. Effects of taurine on primary afferent terminals in the frog spinal cord were examined by a sucrose-gap method applied to a dorsal root (9th or 10th segment). 2. In a normal Ringer solution, taurine (1 mM, applied for 5s at a rate of 0.04 ml s-1, 0.2 mumol) caused a hyperpolarization, but a higher concentration (10 mM, applied at the same rate, 2.0 mumol) caused a biphasic response consisting of a hyperpolarization followed by a slow onset depolarization. A similar biphasic response could also be observed in tetrodotoxin-treated preparations. 3. When the concentration of extracellular Mg2+ was increased up to 9.0 mM, the depolarizing response to taurine was augmented. The rate of the augmentation was dependent upon the extracellular Mg2+ concentration. 4. The depolarizing effect was selectively antagonized by bicuculline in concentrations (10-30 microM) that had no significant antagonizing action on gamma-aminobutyric acid (GABA)-induced depolarization. On the other hand the hyperpolarizing effect of taurine was selectively reduced by strychnine (0.1 microM) which had no antagonizing effect on responses to glycine. 5. These results suggest that in the frog spinal cord there are at least two subtypes of taurine receptor whose pharmacological profiles resemble GABA and glycine receptors in the mammalian central nervous system, and whose sensitivity may be modulated by extracellular Mg2+.

Action Potentials↗
PubMed1988

[Cholangiocarcinoma associated with Caroli's disease].

We report on an autopsy case of cholangiocarcinoma associated with Caroli's disease. A 38-year-old woman was admitted to our hospital suffering from epigastralgia. A diagnosis of Caroli's disease was made after CT, US, and ERCP testing. Because of diffuse intrahepatic bile duct dilatation, the patient was treated with antibioticus. In August 1985, her CA 19-9 level was 3,800 U/ml. This data suggested the development of a carcinoma secondary to Caroli's disease, but no tumor in the liver had been detected in the US and CT examinations. The patient died on February 1, 1986, of hepatorenal failure, approximately seven years after her first admission. An autopsy revealed diffuse dilatation of the intrahepatic bile duct (Caroli's disease) with a cholangiocarcinoma.

Adenoma, Bile Duct↗
PubMed1988

[A case report of primary liver cancer with cerebral metastasis after hepatic resection].

A 67-year-old male, who had a left hepatectomy for hepatocellular carcinoma, was readmitted to our hospital because of a left hemiparesis. A brain computed tomography scan and an r-carotid angiogram revealed a large mass involving the right parietal area, and thus a brain tumor removal was performed. A histological diagnosis of the removed brain tumor found it to be a metastatic, hepatocellular carcinoma. The patient died of pulmonary congestion due to lung metastasis, approximately 2 years and seven months after hepatectomy, and 1 year and three months after the removal of this metastatic brain tumor. In selected cases, the removal of a metastatic brain tumor seems to bring about improvements in the quality and duration of life.

Aged↗
PubMed1988

[Advanced sequelae of apical hypertrophic cardiomyopathy: report of two cases with wall motion abnormalities].

In view of the paucity of reports describing symptoms of increased degree, and deterioration of left ventricular systolic function in patients with apical hypertrophic cardiomyopathy (apical HCM), two cases with congestive heart failure and progressive thinning of previously hypertrophied apical portions of the left ventricle are reported. These were among 13 patients observed from eight to 10 years. Case 1: A 56-year-old man was diagnosed as having apical HCM at the age of 49 years. Severe left ventricular hypertrophy and prominent ST-T changes were observed on ECG during his first admission. His left ventricular end-diastolic pressure (LVEDP) was 24 mmHg and a left ventriculo-gram revealed a decrease in the left ventricular cavity in the apex and marked hypertrophy of the apical wall. Moderate interstitial fibrosis without hypertrophy or disarray of myocytes was observed in a left ventricular endomyocardial biopsy specimen. In two episodes of cardiac arrest he was successfully resuscitated at the age of 50 years. At the age of 55 years, two-dimensional echocardiography revealed thinning and abnormal motion in the apical wall, and a defect in 201T1 accumulation was observed in the same region by perfusion scintigraphy. This patient was readmitted with a diagnosis of cerebral embolism at the age of 56 years. Cardiac catheterization revealed normal LVEDP (8 mmHg), and a left ventriculogram revealed an aneurysm in the left ventricular apex with normal major epicardial coronary arteries. He has been under treatment with antiarrhythmic medications, calcium antagonists and anticoagulants, and has become relatively asymptomatic. Case 2: A 69-year-old-man was diagnosed as having apical HCM after a complete evaluation, including cardiac catheterization, at the age of 59 years. His LVEDP was elevated (17 mmHg), and a left ventricular angiogram revealed marked hypertrophy localized to the apex. Ejection fraction was 64%. A left ventricular endomyocardial biopsy revealed interstitial fibrosis without hypertrophy of myocytes. Thereafter, he has been followed as a New York Heart Association functional class III to IV with occasional elevation of cardiac enzymes but without chest pain or acute changes in his ECGs. However, atrial fibrillation with complete right bundle branch block developed at the age of 60 years. Apical wall thinning and dyskinesis were diagnosed by 2D echocardiography and a defect in the 201T1 accumulation was observed at about 65 years of age. He was readmitted in severe cardiac failure at the age of 69 years, and he was diagnosed as having cardiac asthma with pulmonary capillary wedge pressure of 35 mmHg.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1987

GABAergic modulation of a substance P-mediated reflex of slow time course in the isolated rat spinal cord.

The effects of gamma-aminobutyric acid (GABA) and other drugs which interact with GABA receptors were studied on a reflex of slow time course in the spinal cord preparation isolated from the neonatal rat. A single shock to a dorsal root (L3-L5) elicited a stereotyped series of reflexes, consisting of fast and slow components, recorded from the contralateral ventral root of the corresponding segment. The slow component, i.e. the contralateral slow ventral root potential (v.r.p.) had a time-to-peak of 2-5 s and lasted 20-30 s. Bath-application of GABA (5-20 microM) or muscimol (0.05-0.5 microM) caused a decrease in the amplitude of the contralateral slow v.r.p. without producing any change in the d.c. potential recorded from the ventral root. The monosynaptic reflex recorded from the ipsilateral ventral root was not changed by the drugs at these concentrations. Diazepam (0.1-1 microM) potentiated the depolarizing response of the dorsal root to GABA and markedly depressed the contralateral slow v.r.p. Neither the d.c. potential of the ventral root nor the dorsal root was changed by diazepam. The monosynaptic reflex was also unaffected by the drug. Bicuculline (1 microM) suppressed the GABA-induced depolarization recorded from the dorsal root whilst it markedly potentiated the contralateral slow v.r.p. Baclofen at concentrations from 0.01 to 0.1 microM reduced the contralateral slow v.r.p. The inhibitory action of baclofen on the contralateral slow v.r.p. was more marked than on the monosynaptic reflex. 7 The depolarization of the ventral root induced by a brief application of substance P (SP) was depressed by muscimol, diazepam and baclofen, whereas the depolarization was potentiated by bicuculline. 8 The present results suggest that an intraspinal GABAergic inhibitory mechanism plays a role in the modulation of certain slow spinal reflexes. They also support the hypothesis that SP released from certain primary afferent fibres is a neurotransmitter involved in the contralateral slow v.r.p.

Animals↗
PubMed1986

Effects of ethanol on methyl mercury toxicity in rats.

This study was designed to investigate the effect of different doses of ethanol on the morbidity, mortality, and distribution of mercury in the tissues of groups of rats treated orally once daily with methyl mercury chloride (MMC: 5 mg/kg . d) for 10 consecutive days. Ethanol potentiated the toxicity of methyl mercury in terms of neurological manifestations (hindleg crossings and abnormal gait) and mortality. The magnitude of effect depended on the concentration of ethanol administered. The concentration of mercury in the kidney and brain also increased with the dose of ethanol given. These findings indicate that epidemiologic studies designed to evaluate methyl mercury toxicity must take into account the multiple environmental burdens that can affect the population cumulatively and simultaneously.

Administration, Oral↗
PubMed1985

Opposite actions of forskolin at pre- and postsynaptic sites in rat sympathetic ganglia.

In isolated rat superior cervical ganglia, forskolin, a powerful activator of adenylate cyclase, augmented the amplitude of fast excitatory postsynaptic potentials. Quantal analysis showed that forskolin acts presynaptically to facilitate the release of the transmitter. The time course of the presynaptic action of forskolin paralleled that of the increase in cyclic AMP level in the ganglia. In addition, forskolin exerted a postsynaptic action on the nicotinic acetylcholine receptor so that the acetylcholine-induced depolarization was depressed. The action of forskolin on the nicotinic acetylcholine receptor seems to be unrelated to the cyclic AMP system.

Animals↗
PubMed1985

Mortality and survival for Minamata disease.

Analysis of mortality of 439 deaths that occurred among 1483 patients with Minamata disease (MD) in Kumamoto Prefecture, Japan was performed from the end of 1981. Causes of death and survival rates were studied by means of the standardized mortality ratio (SMR) and life-table technique. Of the 439 deaths (29.6%) in MD cases, the first death occurred in 1954. There was a first peak incidence in 1956 when MD was initially reported, however, the majority of deaths occurred after 1972 when a second and much larger peak was evident. In 1970 an important milestone occurred when the Public Nuisance Relief Law (an anti-pollution law) was enacted. Among its provisions, this law required and enabled verification of MD among people suspected of having been exposed. In contrast to the early cases, later cases of MD were older and their mean age-at-death was not different from that of the general population. The mortality rate for all causes of death was significantly higher in both sexes compared to the general population. Significantly lower survival rates were noted for older patients. The cause-specific mortality rates also showed significantly increased SMRs for liver diseases and nephritis-nephrosis-nephrotic syndrome in male patients, and for nephritis-nephrosis-nephrotic syndrome and other diseases in females. On the other hand, the SMR for senility without mention of psychosis was significantly lower than expected in both sexes.

Actuarial Analysis↗
PubMed1985

The role of substance P as a neurotransmitter in the reflexes of slow time courses in the neonatal rat spinal cord.

In order to reveal the spinal reflexes involving the transmitter action of substance P (SP), the effects of capsaicin and an SP antagonist on the isolated spinal cord of the neonatal rat studied. When a single shock stimulus was given to a dorsal root (L3-L5) or a sciatic nerve, depolarizing responses of various time courses were recorded extracellularly from both ipsi- and contra-lateral ventral roots of the corresponding segments. The reflex response recorded from the contralateral ventral root consisted of fast and slow components, which will be referred to as contralateral fast and slow ventral root potentials (v.r.ps). The latter contralateral slow v.r.p. had a time-to-peak of 2-5 s and lasted 10-30 s. The threshold for the contralateral slow v.r.p. was about two times higher than that for the monosynaptic reflex, and it coincided with the threshold for activating the slow-conducting afferent fibres. The contralateral slow v.r.p. was abolished after the spinal cord was treated with capsaicin (1 microM for 30 min) in vitro. The contralateral slow v.r.p. was absent in the spinal cord derived from 4-day-old rats that had received capsaicin (50 mg kg-1, s.c.) on the 2nd day of life. The contralateral fast v.r.p. and other reflexes of fast time courses remained unaltered after treatment with capsaicin in vitro or in vivo. Administration of an SP antagonist, [D-Arg1, D-Pro2, D-Trp7,9 Leu11]-SP in concentrations of 5-16 microM depressed the contralateral slow v.r.p., but did not affect the monosynaptic reflex, the dorsal root potential and the contralateral fast v.r.p. [D-Arg1, D-Pro2, D-Trp7,9, Leu11]-SP (5 microM) markedly depressed the SP-induced depolarizing response recorded from the ventral root whereas the responses to noradrenaline, 5-hydroxytryptamine, neurotensin and thyrotrophin releasing hormone (TRH) were unaffected by the SP antagonist. The response of the ventral root to acetylcholine was slightly depressed by the antagonist. The SP antagonist at 5-10 microM did not exert any agonist action on the motoneurones. The present results in conjunction with those of previous studies support the hypothesis that SP released from certain primary afferent fibres acts as a neurotransmitter, producing in dorsal horn neurones slow excitatory postsynaptic potentials which lead to the generation of the contralateral slow v.r.p.

Animals↗