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Biomedical subjects

Y Kono

Publications and source records attributed to Y Kono.

At least 55 records · Page 3Linked to original sources
PubMed2000

Effects of bradykinin on prostaglandin I(2) synthesis in human vascular endothelial cells.

The effects of bradykinin on the regulatory mechanisms of prostacyclin synthesis in endothelial cells were investigated in association with intracellular Ca(2+) kinetics, cytosolic phospholipase A(2) (cPLA(2)) activity, and mRNA expression of cPLA(2) and prostaglandin H synthase (PGHS) isoforms. Bradykinin enhanced prostacyclin release from endothelial cells time-dependently, but pretreatment with EGTA H-7 or HOE 140 inhibited bradykinin-induced prostacyclin release. Bradykinin increased both the influx of extracellular Ca(2+) and Ca(2+) release from the intracellular Ca(2+) storage sites. These reactions occurred within 5 minutes after bradykinin stimulation. Within 15 minutes, bradykinin activated cPLA(2) to 1.3-fold the control level. The constitutive expressions of mRNA of cPLA(2), PGHS-1, and PGHS-2 was 87, 562, and 47 amol/microg RNA, respectively. With the stimulation of bradykinin, cPLA(2) mRNA increased to 746 amol/microg RNA in 15 minutes, PGHS-1 mRNA increased to 10 608 amol/microg RNA, and PGHS-2 mRNA increased to 22 400 amol/microg RNA in 180 minutes. Pretreatment with cycloheximide superinduced cPLA(2) and PGHS-2 mRNA expression but almost completely inhibited PGHS-1. Pretreatment with EGTA had effects similar to pretreatment with cycloheximide in the case of cPLA(2) and PGHS-1 but did not affect PGHS-2. These findings suggest that the elevation of cPLA(2) activity caused by the increase of intracellular Ca(2+) concentration is important in the early phase of bradykinin-induced prostacyclin synthesis and that the mechanisms regulating cPLA(2) are different from those regulating PGHS isoforms in endothelial cells.

Bradykinin↗
PubMed2000

Bilateral coronary artery dilatation in a child with Noonan syndrome.

A rare case of a child with Noonan syndrome who had huge bilateral coronary artery dilatation is presented. Noonan syndrome is one of the most common nonchromosomal syndromes seen in children with cardiovascular abnormalities. Coronary artery abnormality should be considered in Noonan syndrome, because this syndrome may be associated with a higher incidence of coronary anomalies than previously thought.

Child↗
PubMed2000

[CT-guided needle biopsy in malignant lymphoma: current techniques and its usefulness].

Histological examination of adequate biopsy specimens is fundamental to the management of patients with malignant lymphoma. Core-needle biopsy with computed tomography potentially provides a better basis for this assessment. Image-guided needle biopsy should be the first procedure performed in the diagnosis of lymphoma, except in easily accessible superficial neck, inguinal, and axillary nodal sites. Recent studies have shown a diagnostic accuracy of 83% to 87%. We describe the biopsy technique that have been successful in our personal experience. From our experience, CT-guided core-needle biopsies prove sufficient information for the diagnosis of and subsequent therapeutic decision to treat most cases of lymphoma.

Biopsy, Needle↗
PubMed2000

An association study between alcoholism and the serotonergic receptor genes.

BACKGROUND: Linkage and association studies of alcoholism using DNA makers have been conducted without conclusive results. The comorbidity of alcoholism with affective disorder indicates that dysfunction of the serotonergic system may play an important role in developing alcoholism. METHODS: We studied the genetic association between alcoholism and alleles of the HTR1A, HTR2A, and HTR2C genes. The subjects were 91 biologically unrelated alcoholics and 90 controls. Polymorphisms of these genes were determined by polymerase chain reaction restriction fragment length polymorphisms, and the data were analyzed by chi2 tests. RESULTS: We found no significant association between alcoholism and the HTR1A, HTR2A, and HTR2C genes. CONCLUSIONS: The study results suggest that these serotonergic receptor genes may not directly contribute to the etiology of alcoholism.

Adult↗
PubMed2000

[Biopsy].

We reviewed the current devices, techniques, guiding images, indications and complications of needle biopsy with CT guidance. The development of new devices such as automated cutting needle has enabled radiologists to obtain tissue specimens of good quality at biopsy. Techniques such as the tandem or coaxial method ensure more a more accurate biopsy route. And helical CT and CT fluoroscopy have markedly shortened the time required for needle biopsy. However, we sometimes encounter minor complications, and rarely major ones, during and after needle biopsy. Some of these complications may be caused by malpractice. Therefore it is important always to pay attention to the possibility of complications of needle biopsy and to minimize radiation exposures from CT fluoroscopy.

Biopsy, Needle↗
PubMed1999

Face immersion in cold water induces prolongation of the QT interval and T-wave changes in children with nonfamilial long QT syndrome.

We investigated the relation between heart rate and the QT interval using face immersion in cold water in children with long QT syndrome (LQTS) without a family history of this condition, and in control children. The face immersion test revealed that all children with high probability of LQTS had a significantly longer QT interval than control children during face immersion, and that the test could induce T-wave alternans or a notched T-wave in all children with a high probability of LQTS.

Adolescent↗
PubMed1999

A role of protein kinase C in the regulation of cytosolic phospholipase A(2) in bradykinin-induced PGI(2) synthesis by human vascular endothelial cells.

The purpose of this study was to elucidate the mechanism by which bradykinin (BK) enhances prostacyclin (PGI(2)) production in human umbilical vein endothelial cells (HUVEC). BK-induced enhancement of PGI(2) synthesis was observed in a dose- and time-dependent manner, and it also increased [Ca(2+)](i) followed by enhancement of cytosolic phospholipase A(2) (cPLA(2)) activity. The PKC inhibitors GF109203X and H7 attenuated the BK-induced increase in [Ca(2+)](i) and inhibited the BK-induced PGI(2) synthesis. Phorbol 12-myristate 13-acetate increased cPLA(2) activity and PGI(2) synthesis but failed to alter [Ca(2+)](i). BK increased cPLA(2) mRNA eightfold by 15 min, and this increase was inhibited by pretreatment with the PKC inhibitors. In response to cycloheximide pretreatment, cPLA(2) mRNA was superinduced. These results suggest that BK stimulates PGI(2) synthesis in HUVEC by activation of cPLA(2) by dual mechanisms: an elevation of [Ca(2+)](i) and a PKC-dependent pathway. Moreover, changes in calcium kinetics and expression of cPLA(2) mRNA may underlie the BK-induced PGI(2) enhancement in these cells.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1999

Relationship between parapapillary atrophy and visual field abnormality in primary open-angle glaucoma.

PURPOSE: To investigate the relationship of parapapillary atrophy measured by confocal scanning laser ophthalmoscopy to visual field sensitivity measured with standard automated perimetry and short-wavelength automated perimetry in patients with primary open-angle glaucoma. METHODS: Forty-seven eyes of 47 primary open-angle glaucoma patients with increased intraocular pressure (> or = 22 mm Hg) were enrolled. Optic nerve head topography and parapapillary atrophy (beta and alpha zones) were assessed by confocal scanning laser ophthalmoscopy. Mean deviation and corrected pattern SD were assessed with standard automated perimetry and short-wavelength automated perimetry. RESULTS: Beta and alpha zones were found in 23 (49%) and 47 (100%) eyes with primary open-angle glaucoma, respectively. The area of beta zone showed significant correlations with MD of standard automated perimetry, corrected pattern SD of standard automated perimetry, and corrected pattern SD of short-wavelength automated perimetry (Spearman r = -0.366, P = .012; r = 0.327, P = .025; and r = 0.436, P = .002, respectively). The area of alpha zone showed a significant correlation with mean deviation of standard automated perimetry (r = -0.378, P = .009). Mean MD of standard automated perimetry, mean corrected pattern SD of standard automated perimetry, and mean corrected pattern SD of short-wavelength automated perimetry were significantly worse in eyes with beta zone than in eyes without beta zone. CONCLUSIONS: Parapapillary atrophy measured by confocal scanning laser ophthalmoscopy, especially beta zone, is associated with glaucomatous visual field loss demonstrated by standard automated perimetry and short-wavelength automated perimetry.

Adult↗
PubMed1999

Parapapillary atrophy in patients with focal visual field loss.

PURPOSE: To examine parapapillary atrophy in normal subjects and patients with primary open-angle glaucoma with focal visual field loss. METHODS: Twenty-nine patients with repeatable early focal visual field loss according to standard automated perimetry (Humphrey program 24-2) and 29 matched (age and disk area) normal subjects were included. Parapapillary atrophy area and optic disk topography were evaluated with a confocal scanning laser ophthalmoscope. The difference in parapapillary atrophy area between normal subjects and patients with glaucoma was examined. Optic disk topography was evaluated by means of the rim-disk area ratio in 36 10-degree sectors and classified into diffuse and focal patterns of neuroretinal rim thinning. In patients with a focal pattern, the locations of rim thinning and parapapillary beta zone atrophy were compared. RESULTS: Beta zone atrophy was detected more frequently in patients with glaucoma (45% [13/29]) than in normal subjects (7% [2/29]), and it was located both superiorly and inferiorly in 92% (12/13) of the glaucoma patients. Alpha zone atrophy was significantly larger in patients with glaucoma than normal subjects (P = .009) but not more frequent (97% [28/29] in both groups). Sixty-one percent (8/13) of glaucoma patients with beta atrophy had diffuse thinning and 31% (4/13) had focal thinning. Eight percent (1/13) did not have neuroretinal rim thinning. In the four patients with both focal rim thinning and beta zone atrophy, the location of rim thinning corresponded to the location of the beta zone atrophy (100% [4/4]). CONCLUSIONS: In patients with early focal glaucomatous visual field loss, the presence and location of parapapillary beta zone atrophy and neuroretinal rim thinning are in good correspondence. Observation of localized parapapillary beta zone atrophy in clinical practice should direct one to more closely examine the optic disk in this region, as it may reveal localized rim thinning in a disk previously considered to be normal. Moreover, diffuse structural change in an eye with only focal functional change, as determined by standard automated perimetry, is consistent with the possibility that structural damage may be more widespread than functional damage in these patients.

Adult↗
PubMed1999

Effects of a bolus injection of adenosine triphosphate on atrioventricular conduction and hemodynamics in patients undergoing coronary artery bypass grafting.

OBJECTIVE: To investigate the effects of adenosine triphosphate (ATP) on atrioventricular (A-V) conduction and hemodynamics in patients undergoing coronary artery surgery. DESIGN: A prospective study. SETTING: University teaching hospital. PARTICIPANTS: Patients scheduled for elective coronary artery bypass graft surgery. INTERVENTIONS: Anesthesia was induced with the same dose of intravenous fentanyl (300 microg) and midazolam (10 mg) for each patient. After the baseline measurement, a bolus dose of 10 mg of ATP (0.19+/-0.03 mg/kg, mean +/- SD) was rapidly injected through a central venous catheter. Right ventricular pacing was conducted at a rate of 40 beats/min during the development of complete A-V block. MEASUREMENTS AND MAIN RESULTS: ATP induced an A-V block in 10 of 12 patients (2:1 block in two patients and complete A-V block in eight patients). The onset of the A-V block was rapid (17.1+/-3.4 seconds) and the duration was short (12.1+/-7.0 seconds). Radial arterial pressure (AP) decreased with the appearance of the A-V block (p < 0.01). Heart rate (HR) returned to the baseline value quickly after the restoration of the A-V block, but recovery of radial AP was delayed. HR increased 1 minute after the ATP injection (p < 0.01). Both HR and radial AP returned to the baseline values 2 minutes after the ATP injection. ST segments on both leads II and V5 of electrocardiograms decreased more than 0.10 mV 1 minute after the ATP injection in one patient. CONCLUSION: A bolus injection of 10 mg of ATP successfully induced a transient A-V block in 83% of the 12 patients. The countermeasures, including ventricular pacing, are indispensable to cope with the subsequent hypotension that may lead to myocardial ischemia, especially in patients with ischemic heart disease.

Adenosine Triphosphate↗
PubMed1999

Effect of probucol on intracellular pH and proliferation of human vascular endothelial cells.

We investigated the effect of probucol on the intracellular pH ([pH]i) and proliferation of human umbilical vein endothelial cells (HUVEC), as well as their production of prostacyclin (PGI2). The addition of probucol produced a biphasic shift in [pH]i, with a brief initial acidification followed by a rapid alkaline shift. After pretreatment with EGTA, the initial decrease in [pH]i was abolished, and the subsequent increase was inhibited. After pretreatment with amiloride, only the increase of [pH]i was abolished. These results suggest that the probucol-induced increase of [pH]i was mainly dependent on Na+/H+ exchange and partly on extracellular Ca2+. In contrast, the addition of LDL produced a decrease of [pH]i. Under Ca2+-free condition, [pH]i was further decreased by LDL. In cells pretreated with amiloride, however, [pH]i was not further decreased by LDL. It was found that probucol promoted cell proliferation, and LDL inhibited cell proliferation. Addition of probucol also enhanced prostacyclin generation by HUVEC. This enhancement of PGI2 generation resulted from increased release of Ca2+ from the storage sites, due not only to increased production of inositol 1,4,5-triphosphate (IP3) but also to the increase of [pH]i. These findings may help to explain the antiatherosclerotic action of probucol.

Amiloride↗
PubMed1999

The mechanism of thrombin-induced prostacyclin synthesis in human endothelial cells with reference to the gene transcription of prostacyclin-related enzymes and Ca2+ kinetics.

This study was designed to evaluate the effect of thrombin on prostacyclin (PGI2) production in cultured human vascular endothelial cells in association with intracellular Ca2+ and with the gene expression of prostaglandin H2 synthase (PGHS) and phospholipase A2 (PLA2) using competitive polymerase chain reaction. Thrombin enhanced the PGI2 synthesis dependent with time. Additionally, thrombin increased the intracellular Ca2+, which stimulates PLA2, resulting in arachidonic acid cleavage from membrane phospholipids and its subsequent conversion into PGI2 through the PGHS pathway. The elevation of intracellular Ca2+ was a result of Ca2+ influx and Ca2+ release from its intracellular storage sites. In this study, PGHS-1 mRNA was constitutively expressed, whereas PGHS-2 mRNA was not. With the stimulation of thrombin, cytosolic PLA2 (cPLA2) mRNA increased 9-fold at 15 min, PGHS-1 mRNA increased 3.4-fold at 180 min, and PGHS-2 mRNA increased 38-fold at 60 min. These results suggest that the elevation of intracellular Ca2+ and the expression of cPLA2, PGHS-1, and PGHS-2 mRNA cause PGI2 generation.

Calcium↗
PubMed1999

Interleukin-1alpha stimulated prostacyclin release by increasing gene transcription of prostaglandin H synthase and phospholipase A2 in human vascular endothelial cells.

This study was conducted to evaluate the effects of interleukin-1alpha (IL-1alpha) on prostacyclin (PGI2) production in cultured human vascular endothelial cells in association with intracellular Ca2+, inositol 1,4,5-trisphosphate (IP3), and with prostaglandin H synthase (PGHS) and phospholipase A2 (PLA2) gene expression by using the competitive polymerase chain reaction (PCR) method. IL-1alpha did not increase PGI2 production for 15 min, but induced an increase of about three-fold relative to that in controls at 60 and 180 min. IL- 1alpha had no effect on intracellular Ca2+ levels throughout the experimental period. In this study, consistent with previous reports, PGHS-1 messenger RNA (mRNA) was constitutively expressed, whereas PLA2 mRNA was not. After stimulation with IL-1alpha, PLA2 mRNA level showed an eightfold increase within 15 min, and PGHS-2 mRNA level increased by 76-fold within 180 min. PGHS-1 mRNA level was increased 1.6-fold at 180 min. These results suggest the existence of regulatory mechanisms of IL-1alpha-induced PGI2 production, which involve PGHS and PLA2 gene transcription.

Base Sequence↗
PubMed1999

Natural antioxidant, chlorogenic acid, protects against DNA breakage caused by monochloramine.

Chlorogenic acid prevented a stepwise conversion of plasmid pUC18 DNA, from I-->form II-->form III, induced by 3 mM monochloramine with a half inhibition of 67.4 microM. Chlorogenic acid reacted with monochloramine in a time-dependent manner, and the reaction rate increased with decreasing pH. These results suggest that chlorogenic acid prevents genotoxicity of monochloramine in gastric mucosa.

Ammonium Chloride↗
PubMed1999

Analysis of the CAG repeat number in a patient with Huntington's disease.

This study was performed to confirm 1) the difference in the trinucleotide CAG repeat number among tissues, 2) somatic mosaicism in each tissue, 3) the correlation of the repeat number with pathological severity in Huntington's disease. The CAG repeat number was determined by analysis of the polymerase chain reaction (PCR) product in various tissues, including central nervous system (CNS) tissues and non-CNS tissues. We also determined the pathological severity grade in each brain section and compared this with the results of CAG repeat analyses. The patient was a Japanese male with Huntington's disease who died at 62 years of age. Genomic DNA was extracted from 10 parts of the central nervous system and 6 parts of other tissues from the patient. Each part of the formalin-fixed brain was subjected to gross and microscopic pathological assessment. The main peaks of CAG repeat in all tissues were 22 and 44. In analysis of somatic mosaicism, high degrees of mosaicism were obtained in the caudate nucleus, putamen and cerebral cortex, in which more severe degeneration was observed by pathological examination. These results, although this is a single case study, indicated that pathological severity did not correlate with the CAG repeat number, but it did relate to the degree of somatic mosaicism. Somatic mosaicism might reflect region-specific neuronal degeneration in Huntington's disease.

Brain↗