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Biomedical subjects

T Asano

Publications and source records attributed to T Asano.

At least 667 records · Page 37Linked to original sources
PubMed1989

Effect of enhanced capillary activity on the blood-brain barrier during focal cerebral ischemia in cats.

We hypothesize that enhanced activity of capillary Na,K-ATPase promotes Na+ influx into the brain and causes early edema formation in focal cerebral ischemia. The pharmacologic suppression of brain capillary Na,K-ATPase as a means to ameliorate edema formation was examined using the middle cerebral artery occlusion model in 36 cats. With the help of a catheter inserted into the middle cerebral artery, the ischemic brain area was directly perfused with 10(-5) M ouabain. Perfusion was maintained as intermittent 15-second pulse injections given every 5 (n = 6) or 2 (n = 6) minutes. By this method, the naturally occurring circulatory conditions during ischemia were not altered. Four hours after ischemia, the cortical specific gravity at each of six locations over the ischemic area was compared with the corresponding ischemic blood flow measured by the H2 clearance technique. The results show that ouabain perfused every 2 minutes significantly ameliorated edema formation compared with six control cats perfused with Krebs-Ringer solution. In a separate series of experiments, the Na+ flux across the blood-brain barrier was studied by injecting 22NaCl together with an intravascular reference (cobalt-57-labeled microspheres 15 microns in diameter) into the ischemic area. The brain uptake index of 22Na was markedly increased in the ischemic cortex of six control cats; ouabain treatment in six cats suppressed the increase of Na+ influx. The results support our hypothesis that brain capillary Na,K-ATPase activity increases during early focal ischemia, leading to enhanced Na+ together with H2O flux across the blood-brain barrier.

Animals↗
PubMed1989

Characteristics of mutant mice (ICGN) with spontaneous renal lesions: a new model for human nephrotic syndrome.

Spontaneous nephrotic mice (ICGN mice), a new mutant strain of mouse from outbred ICR, were clinically, macroscopically, histologically and immunohistochemically studied to establish their value as a model for human nephrotic syndrome. Most of the affected mice developed proteinuria, hypoproteinaemia and hypercholesterolaemia, and some of them developed systemic oedema. A high concentration of blood urea nitrogen (BUN) and a low haematocrit value were also observed. The kidneys of severe cases showed a decrease in size and had a yellowish granular surface. These findings indicated that the mice were terminally affected by chronic renal insufficiency. Histopathology demonstrated glomerular lesions consisting of thickened basement membranes of the capillary loops with irregular spike-like protrusions and enlargement of the mesangium unaccompanied by cellular proliferation. The immunofluorescence technique revealed positive granular staining for IgA, IgG and IgM and to a lesser extent for C3 along the capillary loops in affected mice. The similarity between this spontaneous disease and human nephrotic syndrome caused by idiopathic glomerular lesions is discussed. ICGN mice may be a useful animal model for this human disease.

Animals↗
PubMed1989

Plasma glucagon response to intravenous alanine in obese and non-obese subjects.

To investigate glucagon (IRG) and insulin (IRI) responses to alanine infusion in obesity and to assess the effect of body weight reduction with respect to hormonal balance, we compared six obese subjects with nine normal weight controls. None of the subjects were diabetic by OGTT criteria. Plasma IRI and IRG were measured following IV alanine at a rate of 0.1 g/kg over a period of 2 min. Our obese subjects had an increase in IRG response to alanine, which was due to decreased suppression of alpha-cell function due to insulin resistance. Weight reduction via calorie restriction reduced insulin demand, resulting in reduced plasma IRI by restoring beta-cell function, and the IRG response was paradoxically decreased as compared with that before weight loss. It is conceivable that improvements in insulin sensitivity after body weight reduction may re-establish the normalization of pancreatic beta-cell function and the insulin-induced inhibition of IRG secretion. Our obese subjects were characterized by decreased IRG secretion which was reflected in a change in body weight reduction.

Alanine↗
PubMed1989

Expression and sequences of T cell receptor beta-chain variable genes in the enlarged lymph nodes of C57BL/6-lpr/lpr mice.

An autosomal recessive gene, lpr, is responsible for lymphoproliferation and autoimmunity of lpr-mice, in which background genes are also known to influence the development of autoimmune disease. To define the differences in abnormally proliferating T cells between C57BL/6-lpr/lpr and MRL/Mp-lpr/lpr mice, and to try and understand the influence of background in the differing expression of autoimmune disease in both strains, we analysed the sequences of T cell antigen receptor V beta genes expressed in the cells from the enlarged lymph nodes of C57BL/6-lpr/lpr mice. Eleven beta cDNAs out of the 38 C beta-specific cDNAs contained sequences with open reading frames from the beginning of the variable region to the expected termination codons at the end of the constant regions. Notably, 36% of the functional beta-chain mRNAs expressed V beta 8.3 genes, whereas V beta 8.1 and V beta 8.2 genes were not found. These results are consistent with a relatively lower frequency of the V beta 8.1 or V beta 8.2 expressing cells in the hypertrophic lymph nodes of C57BL/6-lpr/lpr mice, detected by KJ16-133 monoclonal antibody. Interestingly, other V beta genes expressed in these mice were completely distinct from those in MRL/Mp-lpr/lpr mice as described by Singer et al. (1986). The different distribution of V beta genes expressed in C57BL/6-lpr/lpr from that in MRL/Mp-lpr/lpr mice might be related to the differences in the genetic background and the expression of lpr gene-associated autoimmunity.

Amino Acid Sequence↗
PubMed1989

[A case report of successful one-stage operation in TGA (group III) with WPW syndrome].

A patient who had received balloon atrioseptotomy and B-T shunt operation previously experienced recurrent episodes of supraventricular tachycardia, and was refractory to medical treatment since the age to 3. At 9 years, the patient underwent intraoperative electrophysiological mapping which confirmed the earliest breakthrough at the crux of posterior septal region. Rastelli's operation and division of posterior septal Kent was simultaneously performed successfully. Post operative ECG was normalized with abolition of delta wave, and PSVT was gone. We concluded that the division of Kent bundle should be simultaneously performed with operative reconstruction in patients with congenital heart disease and WPW syndrome on postoperative care for SVT.

Bundle of His↗
PubMed1989

Decreased high-affinity epidermal growth factor receptors in psoriatic epidermis.

Using 125I-EGF the distribution of EGF receptors in psoriatic epidermis was autoradiographically examined. Binding sites of 125I-EGF (20 ng/ml) were mainly located at basal and suprabasal cells in normal and uninvolved psoriatic epidermis, whereas they were located at spinous cells as well as at basal and suprabasal cells in affected psoriatic epidermis. Binding of 125I-EGF (1 ng/ml), on the other hand, was observed in normal and uninvolved psoriatic epidermis but not in affected psoriatic epidermis. The majority of EGF receptors in affected psoriatic epidermis were featured by low affinity for EGF.

Autoradiography↗
PubMed1989

[Surgical treatment of spasmodic torticollis: effectiveness of microvascular decompression].

We report two patients of spasmodic torticollis who underwent different types of surgery according to their pathogenetic mechanisms. The first case was a 42-year-old man who had two years history of right-sided antecollis. EMG of the sternocleidal muscle on the affected side showed pathological findings. Characteristic findings on the vertebral angiography were a low position of the branching of tortuous PICA. At operation, we confirmed sandwich-like compression of left accessory nerve between the PICA and vertebral artery. Decompression of the nerve from these arteries led to a remarkable relief of the symptom. The second case was a 70-year-old man whose neck had been forced to bend backward; retrocollis over two years. EMG study was negative. The vertebral angiography showed no abnormality, either. Because there was no evidence of vascular compression on both accessory nerves at surgery, we chose bilateral C1-3 anterior root section which was effective in consequence. We found so far sixteen cases of spasmodic torticollis in the literature including ours who were benefited by microvascular decompression (MVD). All of them presented antecollis or horizontal type. The characteristic operative finding was the compression of the accessory nerve located at between the dural perforation of the vertebral artery and dural attachment of C1 dentate ligament. We can therefore propose a mechanism that the compression at the junction of the central and peripheral myelin causes such a neuroexcitatory symptom as in cases of facial spasm and trigeminal neuralgia.(ABSTRACT TRUNCATED AT 250 WORDS)

Accessory Nerve↗
PubMed1989

Experimental studies on the pharmacokinetics and therapeutic effect of cefbuperazone in biliary infection.

A study was carried out using an experimental biliary infection model to investigate the pharmacokinetic characteristics and therapeutic effect of cefbuperazone in the rabbit. Thirty rabbits were divided into three equal groups; a control group of normal animals, a group of infected animals receiving no cefbuperazone, and a group of infected animals receiving 50 mg cefbuperazone/kg intramuscularly. The experimental infection was made by direct inoculation of a suspension of E. coli into the common bile duct after ligation. The results showed that extremely high levels of cefbuperazone were achieved in bile and tissues of the biliary tract and were higher than those in the blood. Moreover, the levels were maintained at effective concentrations even after 6 hours. Viable bacterial cells from bile and the gall-bladder were barely detectable 24 and 48 hours after infection in the cefbuperazone-treated group, whilst counts remained high in the other infected group. White blood cell counts were increased at 24 hours after infection but were significantly lower in the cefbuperazone-treated group. Histological examination revealed marked inflammatory changes in the gall-bladder and bile duct of infected, untreated animals but few, mild changes only were seen in cefbuperazone-treated animals. Similarly, total bilirubin and liver enzymes were markedly increased in infected animals, but transaminases and alkaline phosphatase were significantly lower in the treated compared to the untreated group. The findings indicate, therefore, that cefbuperazone can be a useful antibiotic in biliary infection.

Animals↗
PubMed1989

[Studies on the operative factors affecting the reduction of chronic subdural hematoma, with special reference to the residual air in the hematoma cavity].

The authors previously reported the effect of preoperative factors affecting the reduction of chronic subdural hematoma. In this report, we evaluated some operative factors, including operative methods, duration of drainage, and residual air volume, with newly developed CT volumetry technique. As described before, the hematoma volume reduces exponentially. An exponential curve was fitted to the reduction curve using the least square method, and its half reduction days (HRD) was calculated. This HRD represents a mathematical indicator of the reduction rate of CSDH. Using this technique, the relationship between this HRD and operative method, the duration of drainage and the volume of the postoperative residual air were examined in 61 patients. Operative method (burr hole or small craniotomy) has no correlation with HRD. The duration of drainage also has no correlation. However, the volume of the residual air was highly correlated with the reduction rate of hematoma (r = 0.430; p less than 0.01). These results suggest that the residual air in the hematoma cavity may delay the reduction rate of the hematoma. Based on these results, the authors pay attention to the following points; 1) Less invasive burr hole method should be selected. 2) Patient's head position should be controlled to make the burr hole at the highest level in the operative field. 3) Hematoma cavity should be filled with saline as much as possible. 4) The inner membrane should never be injured, as it may cause tension pneumocephalus. Moreover, the drainage of cerebrospinal fluid may reduce the counter pressure and it leads to the delay of the hematoma reduction.

Adult↗
PubMed1989

[A dissecting aortic aneurysm involving a right-sided aortic arch].

A 51-year-old woman suddenly developed severe pain in the chest and back, also dyspnea. On admission, she was in a state of preshock. Plain X-ray indicated the lack of the left aortic arch and poor pneumatization in the whole right lung. The thoracic fluid was transparent with yellowish tinge and was contaminated with neither any bacterium nor tubercle bacillus. The response to the Rivalta's reaction was negative. The possibility of pleurisy was, therefore, denied. The ECG and blood biochemical data on the second day suggested the possibility of myocardial ischemia. Plain chest X-ray on the fourth day revealed an increased right pulmonary pneumatization and an enlarged mediastinal shadow toward the aortic arch. Upper pulmonary CT showed a mass on the right side. Enhanced CT disclosed a dissepiment in the center, which was high medially and somewhat low laterally. It was diagnosed as a false lumen due to the lateral displacement of the right aortic arch. Hepatic CT disclosed the tapering of the abdominal aorta from right to left in the prevertebral region. These findings indicated that the aorta descended from the right aortic arch along the right side of the spine and crossed the spine dextrosinistrally at the hepatic level. In addition, dissociant aneurysm was observed in the right aortic arch. Echocardiography showed no evidence of dissociant aneurysm at the aortic base. Chest X-ray, CT and echocardiography showed the dissociation of the aorta from the aortic arch to the abdominal aorta. Thus the diagnosis of De Bakey type III was established. Clinically, DIC and multiorgan disorders were manifested but after medical treatments, the clinical course was uneventful.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Dissection↗