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Biomedical subjects

E Koh

Publications and source records attributed to E Koh.

At least 37 records · Page 2Linked to original sources
PubMed1999

[Clinical study of serum S-100 beta protein as marker of brain injury in cardiovascular surgery].

There is no simple and specific marker of brain injury in cardiovascular surgery. S-100 beta protein is a specific protein of the central nervous system. S-100 beta protein detected in spinal fluid and serum is a reflection of brain injury. The aim of this study was to investigate the influence of extracorporeal circulation (ECC) on the brain, with reference to serum S-100 beta protein level and operative factors. Twenty-two patients (12 undergoing coronary artery bypass grafting (CABG), 2 mitral valve replacement, 2 left ventricular aneurysmectomy, 2 grafting of descending thoracic aneurysm, 1 aortic valve replacement (AVR), 1 CABG with AVR, 1 closure of atrial septal defect, 1 aorto-bifemoral and left subclavian artery bypass grafting) without symptomatic neurological complications underwent cardiovascular surgery using ECC. Serum S-100 beta level was measured by enzyme-linked immunosorbent assay before ECC and half an hour after the end of ECC in cardiovascular surgery. Carotid lesions, calcification of the ascending aorta, history of cerebral infarction, and pulsatile or nonpulsatile flow during ECC were evaluated as the operative factors. The correlation of S-100 beta level after ECC with age, duration of ECC and aortic cross clamp time was examined. Serum S-100 beta level was significantly increased after ECC (0.25 +/- 0.48 microgram/l vs. 0.99 +/- 0.64 microgram/l; p < 0.01). Calcification of the ascending aorta was the only significant operative factor that increased S-100 beta level after ECC (calcification 1.35 +/- 0.71 vs. non-calcification 0.68 +/- 0.37 p < 0.01). S-100 beta level after ECC was related to aortic cross clamp time (r = 0.54; p < 0.05, n = 20). It is suggested that brain injury, as reflected by serum S-100 beta protein, is more frequent in cases with calcification of the ascending aorta or a long aortic cross clamp time. It was concluded that serum S-100 beta is a simple potential marker of cerebral injury in cardiovascular surgery with ECC.

Adolescent↗
PubMed1998

Long-term inhalation of nitric oxide for a patient with primary pulmonary hypertension.

Primary pulmonary hypertension is a disease with a high mortality rate and for which there is no satisfactory medical treatment. The safety of long-term inhalation of nitric oxide (NO) as a treatment is described. A 9-year-old girl inhaled NO for 32 weeks, accompanied with oral administration of beraprost sodium. Although NO did not improve her long-term prognosis, it eased the patient's dyspnea and increased her blood oxygenation. At doses of 20 ppm or more, attempts to withdraw from inhaled NO seemed to lead to an immediate elevation of the pulmonary artery pressure. This rebound phenomenon did not happen at doses under 5 ppm. This case study suggests that long-term inhalation of NO is safe and effective, but that pulmonary hypertension may rebound following withdrawal at higher doses of NO.

Administration, Inhalation↗
PubMed1998

Five paediatric case reports of the use of adenosine in supraventricular tachycardia.

The efficacy, safety and diagnostic usefulness of adenosine in the treatment of supraventricular tachycardia in children were prospectively studied over a 2-year period. Only patients who were stable and without hypotension were included. Adenosine was given at a dose of 0.1 mg/kg and increased to 0.2 mg/kg for the second and third doses if there was no response. Adenosine was used on 5 occasions in 5 patients. Adenosine was found to be effective in terminating supraventricular tachycardia in all 5 patients; 4 responded to a dose of 0.2 mg/kg while 1 responded to 0.1 mg/kg. Wolff-Parkinson White Syndrome was detected in 2 patients after termination of supraventricular tachycardia. Transient hypotension was noted in 1 patient lasting 45 seconds with no haemodynamic consequences. Two patients had transient ventricular ectopics lasting 3 to 5 seconds. One out of 3 patients who were old enough to report side-effects, experienced chest discomfort and dizziness lasting 5 seconds. All side-effects were transient and mild. We concluded that adenosine is effective and safe in terminating supraventricular tachycardia in children after vagal manoeuvres have failed.

Adenosine↗
PubMed1997

Redistribution of intracellular Ca2+ stores after beta-adrenergic stimulation of rat tail artery SMC.

beta-Adrenergic agonists induce the relaxation of vascular smooth muscle by a mechanism that activates the extrusion of Na+ and Ca2+ from the cell. A primary source of contractile Ca2+ resides in the sarcoplasmic reticulum (SR), which releases Ca2+ in response to vasoactive agents through inositol trisphosphate-mediated channels. To determine if smooth muscle relaxation induced by beta 2-adrenergic agonists involves the redistribution of intracellular Ca2+, we studied the effects of isoproterenol (Iso) on freshly isolated, single rat tail artery smooth muscle cells loaded with fura 2, using digital ratiometric fluorescence imaging. Stimulation with 1 microM phenylephrine (PE) or norepinephrine produced phasic and tonic increases in cytoplasmic intracellular Ca2+ concentration ([Ca2+]i) associated associated with cell shortening. Exposure to caffeine and to Ca2(+)-free solutions eliminated the phasic and tonic components, respectively, from the Ca2+ signal. Intermittent superfusion with PE or caffeine was used to evaluate SR Ca2+ stores after stimulation by Iso. Exposure to 1 microM Iso induced a time-dependent decrease in PE-activated peak and tonic [Ca2+]i without any change in resting [Ca2+]i. Intermittent stimulation with 10 mM caffeine revealed a similar decline in peak [Ca2+]i, indicating Iso-dependent depletion of SR Ca2+ stores. The Ca2+ that remained in the SR after prolonged exposure to Iso (30% of the pre-Iso level by 80 min at 22 degrees C) failed to elicit a contractile response. The cells, perfused with a Na(+)- and Ca2(+)-free medium to block Na+/ Ca2+ exchange, prevented depletion of the SR Ca2+ stores by Iso. We propose that Iso inhibits agonist-mediated Ca2+ influx through sarcolemmal Ca2+ channels and activates Ca2+ redistribution from storage sites in the SR to the extracellular compartment by a mechanism that involves Na+/Ca2+ exchange. These combined effects of Iso facilitate smooth muscle relaxation (and reduce vascular tonus) by reducing the increase in cytoplasmic Ca2+ evoked by vasoconstrictors.

Adrenergic beta-Agonists↗
PubMed1997

[Successful surgical correction of incomplete endocardial cushion defect in a 65-year-old female].

We report a case of surgical correction of a 65-year-old female. She presented severe congestive heart failure and preoperative cardiac catheterization showed massive left to right shunt (87%), mild mitral regurgitation, severe tricuspid regurgitation and pulmonary hypertension. The operative procedure consisted of annuloplasty of mitral valve (Kay's method), patch closure of the ostium primum defect and annuloplasty of tricuspid valve. Postoperative examination showed complete competence of mitral valve and improved functional capacity. This is the fourth successful case report of surgical correction of incomplete endocardial cushion defect in patients older than 65-year-old in Japan to our knowledge. Surgical correction of incomplete endocardial cushion defect should be recommended even in elder patients.

Age Factors↗
PubMed1997

[Disorders of sex chromosome].

Disorders of sex chromosome, X and Y, consist of abnormality of the number or structure of the sex chromosome. Because sex chromosomes have a variety of genes related to sexual differentiation, disorders of sex chromosome induce a variety of disorders of sexual differentiation. At first, in this title, the process of normal sexual differentiation is shown. Classical disorders of sex chromosome are Klinefelter syndrome, XX male, XYY male, Turner syndrome, XXX female, and XY female. True hermphroiditism, mixed gonadal dysgenesis, and pure gonadal dysgenesis are also included, because most of these disorders have abnormal sex chromosome. Molecular analysis of sex chromosome is clarifying disorders with a minute abnormality of sex chromosome. They include male infertility, premature ovarian failure, and fragile X syndrome. Explanations of the above disorders are given briefly.

Female↗
PubMed1996

[Coagulation disorders as early predictor of brain injury].

To identify early prognostic value of brain injury, a comparison was made between computerized tomography (CT) findings, coagulation abnormalities, and clinical features in 51 patients with closed head injury. The patients were divided into three groups according to their plasma level of fibrin-fibrinogen degradation product (FDP): normal group (FDP 10 micrograms/ml or less) in 20 patients; moderately abnormal group (FDP 10-40 micrograms/ml) in 15 patients; and highly abnormal group (FDP 40 micrograms/ ml or more) in 16 patients. Cases with a fatal clinical course were mostly associated with very high FDP level. Mortality rate in the highly abnormal group was 44% and 7% in the moderately abnormal group were dead cases, while no cases in the normal group turned out poor outcome. Injury severity, as assessed by Glasgow Coma Scale (GCS) score, correlated with the increase of plasma FDP level. Although severe head injury (GCS 8 or less) was found in 44% of the highly abnormal group and 13% of the moderately abnormal group, normal group only had one case (5%). Very high FDP concentrations were found to be associated with combined hemorrhagic lesions and mass effect on CT scan, but not with a specific localization of brain damage. In summary, the evaluation of coagulation and fibrinolytic function in patients following closed head injury might have both diagnostic and prognostic value.

Adolescent↗
PubMed1996

[A case of video-assisted thoracoscopic surgery for patent ductus arteriosus under transesophageal echocardiography].

A six-year-old boy with patent ductus arteriosus was successfully treated by thoracoscopic surgery under transesophageal echocardiography, by which interruption of the ductal flow was confirmed. Postoperative course was uneventful and the patient was discharged on the 3rd postoperative day. The transesophageal echocardiography was effective to confirm disappearance of the flow in the operating room real-time. Video-assisted endoscopic surgery have reduced operative trauma in adult thoracic and general surgery, and can be safely applied to pediatric patients with patent ductus arteriosus. This technique may be an effective addition to the staged management of more complex forms of congenital heart disease.

Child↗
PubMed1996

[Experience of carperitide (synthetic human-atrial natriuretic peptide) after cardiovascular surgery].

Recently carperitide (synthetic human-atrial natriuretic peptide) in known to be useful for the care of acute heart failure. Stretch of the atrial wall has been suggested to be on one of the important factors involved in peptide release. The 8 patients were undertaken cardiac surgery. Carperitide was infused intravenously during postoperative period in these patients and the effects of carperitide were examined. Blood pressure (BP), central venous pressure (CVP), mean pulmonary arterial pressure (PA), pulmonary capillary wedge pressure (PCWP), cardiac index (CI), systemic vascular resistance (SVR), pulmonary vascular resistance (PVR) were monitored by Swan-Ganz catheter, and urinary volume per body weight (UV/kg) were measured. The variables were determined before and after the intravenous infusion of carperitide at 0.1 to 0.2 microgram/kg/min. BP, CVP, PA, PCWP, SVR, and PVR were decreased, and CI and UV/kg were increased after administration of carperitide. These results suggest that carperitide is the useful agent for the postoperative care of cardiovascular surgery especially in the point of decreasing BP and increasing urination.

Aged↗
PubMed1995

Lysophosphatidylcholine causes Ca2+ influx, enhanced DNA synthesis and cytotoxicity in cultured vascular smooth muscle cells.

The effects of lysophosphatidylcholine (LPC), a vasoactive phospholipid, on intracellular free calcium concentration ([Ca2+]i), DNA synthesis and cytotoxicity of vascular smooth muscle cells (VSMC) were studied. LPC from 10(-7) to 10(-5) mol/l dose-dependently induced a sustained increase in [Ca2+]i. In contrast to the response of [Ca2+]i induced by angiotensin II, that induced by LPC was totally abolished when extracellular Ca2+ was removed, was not affected by pretreatment of the cells with islet-activating protein, and was not desensitized by repeated addition. 8-(N,N-Diethylamino)octyl 3,4,5-trimethoxybenzoic acid (TMB-8), an inhibitor of Ca2+ release from intracellular Ca2+ stores, 1-(5-isoquinolinesulfonyl)-2-methylpiperadine dihydrochloride (H-7), an inhibitor of protein kinase C, KT5823, an inhibitor of protein kinase G, and Ca2+ channel blockers failed to suppress the LPC-induced increase in [Ca2+]i. LPC at 10(-5) mol/l caused significant stimulation of [3H]thymidine incorporation into VSMC, and at concentrations of 10(-5) mol/l and higher dose-dependently stimulated release of lactate dehydrogenase in cell culture supernatants. Moreover, digitonin mimicked the effects of LPC on [Ca2+]i, and also caused similar effects to those of LPC on DNA synthesis and cytotoxicity in VSMC. These observations suggest that LPC causes both cell growth and cell injury of VSMC, at least partly, through its detergent action, causing membrane leakiness and resultant [Ca2+]i overload in vitro, thus indicating the possible participation of LPC in atherosclerosis and/or injury of the vascular wall.

Animals↗
PubMed1995

Detection of aberrations in androgen receptor gene by analysis of single-stranded conformation polymorphisms in polymerase chain reaction products.

Analysis of single-stranded conformation polymorphisms in polymerase chain reaction (PCR) products (PCR-SSCP) is a sensitive method for detecting point mutations in genomic DNA. To investigate its utility in examining the androgen receptor gene, we analyzed data on a patient with the testicular feminization syndrome (TFS) with a known point mutation in exon C. We detected mobility shifts of fragments of the corresponding region. Since examination of the subject's brother (legally sister), who also has TFS, revealed an identical shift pattern, we sequenced the exon C of the sibling and detected a mutation identical to that in the former. We conclude that PCR-SSCP is available for screening mutations of the androgen receptor gene.

Adult↗
PubMed1995

Epstein-Barr virus nuclear protein 2 transactivation of the latent membrane protein 1 promoter is mediated by J kappa and PU.1.

Expression of the Epstein-Barr virus (EBV) latent membrane protein 1 (LMP-1) oncogene is regulated by the EBV nuclear protein 2 (EBNA-2) transactivator. EBNA-2 is known to interact with the cellular DNA-binding protein J kappa and is recruited to promoters containing the GTGGGAA J kappa recognition sequence. The minimal EBNA-2-responsive LMP-1 promoter includes one J kappa-binding site, and we now show that mutation of that site, such that J kappa cannot bind, reduces EBNA-2 responsiveness by 60%. To identify other factors which interact with the LMP-1 EBNA-2 response element (E2RE), a -236/-145 minimal E2RE was used as a probe in an electrophoretic mobility shift assay. The previously characterized factors J kappa, PU.1, and AML1 bind to the LMP-1 E2RE, along with six other unidentified factors (LBF2 to LBF7). Binding sites were mapped for each factor. LBF4 is B- and T-cell specific and recognizes the PU.1 GGAA core sequence as shown by methylation interference. LBF4 has a molecular mass of 105 kDa and is probably unrelated to PU.1. LBF2 was found only in epithelial cell lines, whereas LBF3, LBF5, LBF6, and LBF7 were not cell type specific. Mutations of the AML1- or LBF4-binding sites had no effect on EBNA-2 transactivation, whereas mutation of the PU.1-binding site completely eliminated EBNA-2 responses. A gst-EBNA-2 fusion protein specifically depleted PU.1 from nuclear extracts and bound in vitro translated PU.1, providing biochemical evidence for a direct EBNA-2-PU.1 interaction. Thus, EBNA-2 transactivation of the LMP-1 promoter is dependent on interaction with at least two distinct sequence-specific DNA-binding proteins, J kappa and PU.1. LBF3, LBF5, LBF6, or LBF7 may also be involved, since their binding sites also contribute to EBNA-2 responsiveness.

Antigens, Viral↗
PubMed1994

Increased release of platelet-derived growth factor from platelets in chronic liver disease.

The concentrations of platelet-derived growth factor in serum in 7 healthy controls (61 +/- 9 years; mean +/- SD) and 10 patients (62 +/- 8 years) with chronic liver disease (chronic hepatitis and/or liver cirrhosis) were compared. The plasma concentration of platelet-derived growth factor was below the detection limit (< 0.45 microgram/l) in all the subjects studied. The peripheral blood platelet count in patients with chronic liver disease was significantly lower than that in control subjects. However, the concentration of platelet-derived growth factor in serum, which was assumed to be released from platelet, was similar in patients with chronic liver disease and control subjects. These results indicate that the mean amount of platelet-derived growth factor released from the same number (10(9)) of platelets, calculated from the serum platelet-derived growth factor concentration and the peripheral blood platelet count, in patients with chronic liver disease (33 +/- 11 ng/10(9) platelets) was significantly (p < 0.01) higher than that in control subjects (14 +/- 5 ng/10(9) platelets). Moreover, the amount of platelet-derived growth factor released from 10(9) platelets inversely correlated with the serum concentration of pseudocholinesterase activity (r = -0.65, p < 0.01), and correlated positively (r = 0.91, p < 0.01) with the percent retention of indocyanine green in serum, in all subjects studied. These findings suggest that the amount of platelet-derived growth factor releasable from platelets of patients with chronic liver disease is higher than that in normal subjects and that it correlates with the severity of the disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Partial DiGeorge syndrome at the age of thirty-four.

A 34-year-old man with partial DiGeorge syndrome suffered from seizures and mental retardation from the age of three years. He was diagnosed as having primary hypoparathyroidism by the Ellsworth-Howard test at the age of 22. He was also found to have a right aortic arch. Immunological studies revealed the presence of immature T cells (CD 38+, OKT 9+), although the subsets and function of his T cells were almost normal. The facts that the cardiovascular anomaly and immunodeficiency were mild and the hypoparathyroidism was well controlled, may account for his survival to this age.

Adult↗
PubMed1994

[Effects of pravastatin administration for 12 months on serum lipid levels in aged patients with hypercholesterolemia].

To evaluate long-term efficacy of pravastatin, we administered this HMG-CoA reductase inhibitor at a mean dose of 9.9 mg/day to 208 aged patients with serum levels of total cholesterol (TC) over 220 mg/dl (mean +/- SD aged of 70 +/- 7 years; 62 males and 146 females) for 12 months. The mean serum value of TC significantly decreased from the basal level of 265 mg/dl to 216 mg/dl in the 3rd month, and this decrease was maintained throughout the observation period. Similar change was observed in the serum level of low density lipoprotein-cholesterol (LDL-C). Although the mean serum level of high density lipoprotein-cholesterol (HLC-C) in all patients did not change significantly, the HDL-C level in 34 patients with a HDL-C level below 40 mg/dl significantly increased from the 3rd month. The mean serum level of triglyceride (TG) in all patients significantly decreased from the 3rd month, and this decrease in the TG was more prominent in 101 aged patients with TG levels higher than 150 mg/dl. In 168 aged patients on 10 mg/day of pravastatin throughout the period, there were significant negative correlations between the ratio of the decrease in TC in basal serum and each of the basal serum TC levels (r = -0.345, p < 0.001) and age of the subjects (r = -0.208, p = 0.007). These results indicate that long-term administration of pravastatin is effective treatment for lipid metabolism even in aged patients.

Aged↗
PubMed1994

Effects of an angiotensin II receptor antagonist, CV-11974, on angiotensin II-induced increases in cytosolic free calcium concentration, hyperplasia, and hypertrophy of cultured vascular smooth muscle cells.

The effects of CV-11974, a potent nonpeptide antagonist of the angiotensin II (AII) type-1 receptor (AT1), on cytosolic free calcium concentration ([Ca2+]i), hyperplasia, and hypertrophy of cultured vascular smooth muscle cells (VSMC) from rat aorta were studied. [Ca2+]i was measured by fura 2, and hyperplasia and hypertrophy were determined by incorporation of [3H]thymidine and [3H]leucine, respectively. CV-11974 had no effect on [Ca2+]i itself, but suppressed 10(-7) M AII-induced increase in [Ca2+]i dose dependently at concentrations from 10(-10) M and completely at 10(-7) M. CV-11974 suppressed both Ca2+ release from intracellular Ca2+ stores and Ca2+ influx from the extracellular space. However, CV-11974 had no effect on the increases in [Ca2+]i induced by prostaglandin F2 alpha (PGF2 alpha), a potent vasoconstrictor, or ionomycin, a Ca2+ ionophore. These results indicate that the suppressive effects of CV-11974 act on the binding of AII and its specific receptors. AII 10(-7) M increased the synthesis of DNA and protein to 1.5 and 1.7 times the control values, respectively. CV-11974 had no effect on synthesis of DNA or protein, but suppressed the AII-stimulated synthesis of DNA and protein dose dependently at concentrations > or = 10(-8) and 10(-10) M, respectively and completely at 10(-6) M. These results indicate that AII increases [Ca2+]i and synthesis of DNA and protein in VSMC through activation of AT1. CV-11974 showed no partial agonistic effects on AII. Thus, CV-11974 may act not only as an antihypertensive agent, but also as an inhibitor of vascular injury stimulated by AII.

Angiotensin II↗
PubMed1993

Semiconductor laser-induced fluorescence detection in capillary electrophoresis using a cyanine dye.

Cy5, an activated carboxyl cyanine fluorophore, was characterized by capillary electrophoresis (CE) using a semiconductor laser at 652 nm to induce fluorescence. Hydrolysis of the activated Cy5 in the presence of ammonia results in the formation of a mono- and diamide and a dicarboxylic acid. A Cy5-labeled oligonucleotide M13 primer for DNA sequencing (M13mp18 template) was synthesized with a purity of better than 95%. The labeled primer was analyzed by liquid chromatography, using UV-visible detection, and by CE, monitored by laser-induced fluorescence (LIF) detection. Analysis of the Cy5-labeled oligonucleotide primer by CE-LIF in a 9% polyacrylamide gel-filled capillary indicated the purity of the major Cy5-oligonucleotide primer was greater than 90%. The detection sensitivity for Cy5-based CE-LIF detection system with a 2.5-mW red semiconductor laser is about 10(-10) M.

Base Sequence↗