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Biomedical subjects

K Yasui

Publications and source records attributed to K Yasui.

At least 289 records · Page 16Linked to original sources
PubMed1989

[A case of rapidly progressive pulmonary pulmonary hypertension in a 14-year-old girl].

A 14-year-old girl was admitted with chief complaints of edema and chest pain. She had hepatomegaly, but did not have heart murmur and accentuation of the pulmonary component of the second heart sound. The electrocardiogram showed right axis deviation, negative T wave in V3,4 and ST depression in III, aVF. But right ventricular hypertrophy was not dominant. Chest radiography showed a cardiothoracic ratio of 54% and a slight prominence of proximal pulmonary arteries. The edema was soon diminished only by the diuretics, but it appeared again without the diuretics. At the cardiac catheterization 3 months after the onset of symptoms, the pulmonary arterial pressure was 150/85 mmHg and the pulmonary resistance was 3,232 dyn/sec/cm5. The right atrial pressure was 9.5 mmHg and oxygen saturation at the pulmonary artery was 31.0%. Prostaglandin E1 reduced the pulmonary artery pressure only a little, but raised the systemic pressure. The patient was treated with several vasodilators, but her condition deteriorated rapidly and she developed severe right ventricular failure. She died only 8 months after the onset of symptoms and 5 months after the catheterization. At autopsy, histological examination demonstrated intimal fibrotic thickening of the small-sized pulmonary arteries and organizing thrombus. But there was not plexiform lesion. Heart failure was easily improved when she was first admitted. But after 3 months the cardiac catheterization revealed that her condition was already severe. Several vasodilators was not effective to such a rapidly progressive primary pulmonary hypertension.

Adolescent↗
PubMed1989

[Clinical usefulness of three-dimensional brain imaging with N-isopropyl-p-[123I]iodoamphetamine (IMP)].

Three-dimensional reconstruction from N-isopropyl-p-[123I]iodoamphetamine (IMP) tomography has been applied clinically to the detection of perfusion defects in 22 cases (15 cerebrovascular diseases and 7 normal controls confirmed by CT and MRI), with data being analyzed in terms of receiver operating characteristic curves (ROC). The results showed that three-dimensional (3-D) image could make better diagnostic capability especially in inexperienced examiner and that it was useful decreasing of difference of diagnostic capability. 3-D image could be taken within 1 minute and 15 seconds. We concluded that the three-dimensional brain imaging with IMP using this system was clinically useful because examiner could easily diagnose perfusion defects.

Aged↗
PubMed1988

Protection of mice against Japanese encephalitis virus by passive administration with monoclonal antibodies.

We have identified and characterized nine antigenic epitopes on the E envelope of Japanese encephalitis virus (JEV) by using mAb. Passive administration of most of the anti-JEV mAb protected mice from i.v. challenge with 1.5 x 10(3) plaque-forming units of JEV, JaGAr-01 strain. Some mAb, which possess high neutralization activity in vitro, showed high protection, and JEV-specific N mAb 503 was found the most protective. Even an injection of 2.5 micrograms/mouse of mAb 503 protected all mice from JEV infection. Furthermore, an injection of about 200 micrograms of mAb 503 on day 5 postinfection protected 82% of the mice, even when JEV was detected in more than 85% of the infected mouse brains. Synergism of protection was observed with mixtures of several mAb directed against different epitopes. Although in a murine macrophage cell line, all of the mAb groups showed antibody-dependent enhancement (ADE) of JEV infectivity in vitro, and only two flavivirus cross-reactive mAb groups showed ADE of dengue virus type 2. The ADE of JEV by mAb seems not to be harmful for in vivo protection experiments, except for two mAb groups: mAb 302 and 201 showed little or no protective activity against JEV infection and, rather, caused early death in infected mice.

Animals↗
PubMed1988

Increased production of superoxide anion by neonatal polymorphonuclear leukocytes stimulated with a chemotactic peptide.

In order to assess the functional property of neonatal polymorphonuclear leukocytes (PMNs), we studied their chemoattractant-stimulated superoxide anion (O2-) production using a soluble chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP) as a PMN stimulus. O2- production by neonatal PMNs was increased: when stimulated with 10(-7)M FMLP, O2- values (nanomoles; mean +/- SE) produced by 10(6) PMNs were 16.5 +/- 1.3 for neonatal PMNs and 12.6 +/- 0.6 for adult PMNs (p less than .02). When studied under various concentrations (10(-9) to 10(-6)M) of FMLP, neonatal PMNs produced more O2- than adult cells under the stimulation of a lower concentration (10(-8)M) as well as a higher concentration (10(-7)M) of FMLP. The increased O2- production by neonatal PMNs was also observed under their stimulation by phorbol myristate acetate. Neonatal and adult PMNs produced equal amounts of O2- when stimulated with a particulate stimulus of opsonized zymosan. To analyze further the mechanism for the increase in FMLP-induced O2- production by neonatal PMNs, we next studied whether there was some abnormality in their FMLP receptors. Neonatal PMNs had normal numbers of FMLP receptors; the receptor numbers (mean) per cell were 54,000 in neonatal PMNs and 56,000 in adult cells. Additionally, the FMLP receptors had normal affinity for the peptide. These results demonstrate that the increased production of O2- by FMLP-stimulated neonatal PMNs is not due to the abnormality of its binding to the receptors but is due to that of the subsequent events.

Adult↗
PubMed1988

Seroepidemiological study of infection with West Nile virus in Karachi, Pakistan, in 1983 and 1985.

The prevalence of West Nile (WN) virus infection in Karachi, Pakistan, was unknown until 1982. It had been noticed that there were more than a few patients with encephalitides in Karachi, and it was supposed that Japanese encephalitis (JE) cases would be found among them. Therefore, a seroepidemiological study was conducted to define the prevalence of WN virus infection and the possible occurrence of JE virus infection in the Karachi area. Prevalences of haemagglutination inhibition (HI) and neutralization (NT) antibodies against WN virus were studied among 81 serum samples (in July, 33 samples; in September, 48) during 1983, and among 156 paired serum samples that were collected twice, in July and October of 1985. Nearly the same antibody-positive rates were obtained in July of both years (1983: HI 55%; 1985: HI 53%; NT 50%); the rates increased slightly during September/October (1983: HI 65%; 1985: HI 59%, NT 54%). Among 156 paired samples in 1985, 20 (13%) and 12 (8%) showed positive- or negative-antibody conversion between July and October. Two serum samples from each of 156 residents obtained in July had a significantly higher NT antibody titre against JE virus than against WN virus (in case 1, JE 1:80, WN less than 1:10; in case 2, JE 1:40, WN less than 1:10). This is the first report to show the prevalence of WN virus infection in Karachi, Pakistan.

Antibodies, Viral↗
PubMed1988

Miconazole and amphotericin B alter polymorphonuclear leukocyte functions and membrane fluidity in similar fashions.

The influence of miconazole on polymorphonuclear leukocytes (PMN) was investigated and compared with that of amphotericin B (AmB). Human PMN were preincubated in vitro with miconazole or AmB at therapeutically attainable concentrations in plasma, and their chemotactic functions were assessed with the synthetic chemotactic peptide N-formylmethionyl-leucyl-phenylalanine (FMLP). Changes in membrane fluidity of PMN were examined by an excimer-forming lipid technique. Adherence of PMN was measured by a nylon fiber column method. Miconazole and AmB pretreatment irreversibly depressed PMN random migration and chemotaxis under agarose but did not influence superoxide anion production. Both miconazole and AmB increased PMN adherence. Miconazole and AmB lowered the binding affinity of FMLP receptors on PMN and decreased the membrane fluidity in a similar manner. These results demonstrate that miconazole and AmB alter selected in vitro membrane properties of human PMN.

Amphotericin B↗
PubMed1988

Abnormal membrane fluidity as a cause of impaired functional dynamics of chemoattractant receptors on neonatal polymorphonuclear leukocytes: lack of modulation of the receptors by a membrane fluidizer.

Membrane properties associated with chemoattractant-mediated cellular responsiveness of neonatal polymorphonuclear leukocytes (PMN) were analyzed using n-formylmethionyl-leucyl-phenylalanine. Inasmuch as aliphatic alcohols as a membrane fluidizer can enhance the chemoattractant binding and affect subsequent cellular responsiveness in adult PMN, neonatal PMN were studied for such properties by their treatment with iso-propyl alcohol, an aliphatic alcohol. The alcohol (less than 2.5%) treatment enhanced the N-formylmethionyl-leucyl-phenylalanine binding to adult PMN, but there were no changes in the N-formylmethionyl-leucyl-phenylalanine binding to neonatal PMN. Although the N-formylmethionyl-leucyl-phenylalanine-induced subsequent responsiveness including migration, lysosomal enzyme release and superoxide anion production were modulated by the alcohol treatment in adult PMN, there was no such modulation in neonatal PMN. Because membrane fluidity is largely involved in the regulation of the receptor functions, the membrane fluidity of neonatal PMN was next measured by an excimer-forming lipid technique in flow cytometry. The membrane fluidity value (0.45 +/- 0.037) of neonatal PMN was lower than that (0.74 +/- 0.072) of adult PMN (p less than 0.01). Although the aliphatic alcohol enhanced the membrane fluidity of adult PMN, it did not affect the membrane fluidity of neonatal PMN. We conclude that there is abnormal membrane fluidity as a cause of impaired functional dynamics of the chemoattractant receptors, which appears to underlie the defective modulation of cell functions by the membrane fluidizer in neonatal PMN.

1-Propanol↗
PubMed1988

Isolation, physico-chemical properties and biological activity of pamamycin-607, an aerial mycelium-inducing substance from Streptomyces alboniger.

Pamamycin-607, which showed aerial mycelium-inducing activity, has been isolated from Streptomyces alboniger IFO 12738. At 0.1 microgram/disc it induces aerial mycelia in the aerial mycelium-negative strain of S. alboniger but inhibits growth of the substrate mycelia at 10 micrograms/disc. It also acts as an antibiotic against some fungi and bacteria. When KMnO4 was partitioned with pamamycin-607 between benzene and water, MnO4- but no K+ was transferred from the water to the benzene layer; pamamycin-607 was thus shown to be a novel anion-transfer antibiotic.

Anti-Bacterial Agents↗
PubMed1988

[Nd:YAG laser treatment of recurrent adenomas in the preserved rectum in patients with a ileo-rectal anastomosis in familial polyposis coli].

Eight patients with ileo-rectal anastomosis following a total colectomy for familial polyposis coli underwent Nd: YAG laser therapy to treat recurrent adenomas in the preserved rectum after the operation. The median follow-up period for these eight patients has been 4 years and 7 months. Of the eight patients, one underwent a mucosectomy of the preserved rectum and an ileo-anal pull-through five years after the first operation because of recurrent diffuse polyposis of the preserved rectum. In the remaining seven patients, Nd:YAG laser therapy was found to be effective in the abration of recurrent polyps.

Adenoma↗
PubMed1988

[Influence of total pancreatectomy on the secretion of human growth hormone and the endocrine pancreas].

To evaluate the effect of total pancreatectomy on the secretion of human growth hormone, twenty-six patients undergoing total pancreatectomy and twelve healthy subjects (controls) were investigated. Blood glucose (BG), plasma insulin (IRI), C-peptide (CPR), immunoreactive glucagon (IRG) and human growth hormone (HGH) levels were determined. In the glucose tolerance test, the mean basal blood glucose level in the patients before operation was significantly higher than the level in the controls. The basal blood glucose level in the patients after operation was still higher than the level before operation. The responses of IRI, CPR, and IRG secretion after arginine infusion in the patients before operation were less than those in the controls. After operation, arginine infusion did not alter the levels of IRI, CPR and IRG. The mean basal HGH levels were not significantly different between the controls and the patients before and after operation. However, a statistically significant correlation was shown between the basal values of plasma HGH and those of plasma IRI in the patients after operation. Thus, it suggested that the basal secretion of HGH is closely related to the exogenous plasma insulin levels in the pancreatectomized patients. After arginine infusion, the HGH levels in the patients before operation were lower than the those in the controls, but insignificant. After operation, mean HGH levels were significantly lower than those before operation. These findings suggested the absence of pancreatic endocrine function caused by total pancreatectomy resulted in decreased responses of HGH secretion after arginine infusion.

Adult↗
PubMed1988

New therapeutic approach to aortic dissection complicated by cardiac tamponade.

The management of aortic dissection with cardiac tamponade may result in increased blood pressure and thereby itself make the aortic dissection worse. Nevertheless, it is important to prevent cardiac failure caused by cardiac tamponade. We describe a case of aortic dissection with cardiac tamponade. Echocardiography and aortography showed DeBakey IIIb-type aortic dissection with retrograde dissection, complicated by cardiac tamponade and aortic insufficiency. To treat this condition, a new therapeutic approach was undertaken. A vasodilator was administered, then pericardiocentesis guided by echocardiography was performed. To prevent abrupt elevation of blood pressure in response to the relief of cardiac tamponade, the pericardial aspiration was carried out slowly--it took four hours for the complete drainage of 415 ml of blood--and a vasodilator, sodium nitroprusside, was administered. After drainage, cardiac function was reversed fully, and the systolic pressure was controlled under 140 mmHg. Then, using extra-corporeal circulation, the surgical procedure was performed successfully. We conclude that it is useful to treat cardiac tamponade by controlling blood pressure with slow drainage and use of a vasodilator in preparation for performing the surgical procedure.

Aortic Dissection↗
PubMed1988

Increases in neutrophil counts by purified human urinary colony-stimulating factor in chronic neutropenia of childhood.

Clinical effects of purified human urinary colony-stimulating factor (CSFHU) were studied in nine patients with chronic neutropenia of childhood who ranged in age from 1 to 18 years. The patients were given CSFHU at a dose of 6 x 10(6) U/m2/d for seven consecutive days, and their peripheral neutrophil counts were serially followed for 6 to 12 months. In addition, changes in bone marrow morphology and granulocyte-macrophage colony-forming cells (GM-CFUs) were studied. Transient increases in neutrophil counts occurred during the first 4 weeks in all patients except one. Repeated increases were seen in a cyclic fashion in five patients. Three of the patients recovered from the neutropenia after several cycles of fluctuation of neutrophil counts; the counts (per microliter) reached 5,880, 5,640, and 2,000 as compared with pretreatment levels (mean +/- 2 SD) of 80 +/- 164, 182 +/- 250, and 2 +/- 14, respectively. The percentage (mean +/- SE) of marrow neutrophilic cells increased from 30.4% +/- 7.0% to 34.9% +/- 6.9% (P less than .05) and the ratio of the later neutrophil precursors to the earlier ones from 1.02 +/- 0.27 to 1.42 +/- 0.36 (P less than .02) 2 weeks after CSFHU infusion. There were no changes in GM-CFU numbers. These results indicate that CSFHU can increase neutrophil counts by increasing the number and maturity of the marrow neutrophil precursors in some types of childhood chronic neutropenia.

Adolescent↗
PubMed1988

Defective interleukin-1 production in a familial monocyte disorder with a combined abnormality of mobility and phagocytosis-killing.

Monocytes in a familial monocyte disorder, a recently recognized primary immunodeficiency syndrome, with impaired phagocytic functions were studied for their ability to produce interleukin 1 (IL-1) as well as the surface property. Monocytes from two children (siblings) with the disorder possessed CD11b, CD13, CD14, CD33, Ia and LFA-1/Mac-1/p150,95 beta subunit antigens as determined by flow cytometry. Electron microscopic cytochemistry showed that the monocytes had surface glycoproteins reactive with four representative lectins. The IL-1 production by monocytes was assayed in the two patients and compared with that in six children with primary immunodeficiency syndromes and some monocyte abnormalities; three had congenital neutropenia, two had hyper-IgE syndrome, and one had defective monocyte chemotaxis. Monocyte culture supernatants were prepared with stimulation by lipopolysaccharide or silica, and their IL-1 activity was measured by the mouse thymocyte-proliferation assay. The patients' monocytes were defective in IL-1 production: the values were less than 1.0% of the control monocyte values (n = 12) and were in contrast with those of congenital neutropenia monocytes of 186.2% to 204.3%. These results demonstrate a familial monocyte disorder which is characteristic among the immunodeficiency syndromes with regard to the defective IL-1 production and the impaired phagocytic functions.

Adolescent↗
PubMed1987

Intrinsic DNA-dependent ATPase activity of reverse gyrase.

Reverse gyrase is a type I DNA topoisomerase that promotes positive supercoiling of closed-circular double-stranded DNA through an ATP-dependent reaction, and it was purified from an archaebacterium, Sulfolobus. When ATP is replaced by UTP, GTP, or CTP, this enzyme just relaxes the negatively supercoiled closed-circular double-stranded DNA. We found that reverse gyrase hydrolyzes ATP through a double-stranded DNA-dependent reaction. The superhelicity of the DNA did not affect the ATPase activity. However, reverse gyrase does not hydrolyze UTP, GTP, or CTP. Therefore, any of the four nucleotide 5'-triphosphates acts as an effector for the topoisomerase activity of reverse gyrase, but only ATP supports the positive supercoiling of closed-circular double-stranded DNA, through the energy released on its hydrolysis. Single-stranded DNA was a much more potent cofactor for the ATPase activity of the enzyme than double-stranded DNA, and it acted as a potent inhibitor for the topoisomerase activity on double-stranded DNA. These results indicate that reverse gyrase has higher affinity to single-stranded DNA than to double-stranded DNA, which suggests a cellular function of the enzyme.

Adenosine Triphosphatases↗
PubMed1987

Decreased numbers of chemotactic factor receptors in chronic neutropenia with defective chemotaxis: spontaneous recovery from the neutrophil abnormalities during early childhood.

Childhood chronic neutropenia with decreased numbers of chemotactic factor receptors as well as defective chemotaxis was first demonstrated in an 8-month-old girl. Chemotactic factor receptors on neutrophils were assayed using tritiated N-formyl-methionyl-leucyl-phenylalanine (3H-FMLP). The patient's neutrophils had decreased numbers of the receptors: numbers of the receptors were 20,000 (less than 3 SD) as compared with those of control cells of 52,000 +/- 6,000 (mean +/- SD) (n = 10). The neutropenia disappeared spontaneously by 28 months of age parallel with the improvement of chemotaxis and increase in numbers of chemotactic factor receptors. These results demonstrate a transient decrease of neutrophil chemotactic factor receptors as one of the pathophysiological bases of a transient defect of neutrophil chemotaxis in this disorder.

Agranulocytosis↗