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Biomedical subjects

I Park

Publications and source records attributed to I Park.

At least 55 records · Page 3Linked to original sources
PubMed1994

Asynchronous volume changes of the two ventricles after Fontan operation in patients with a biventricular heart.

Coordinated contraction of the ventricle is an important determinant of pump function, which seems to be particularly important in Fontan circulation with one pumping ventricle. We analyzed the synchronism of contraction of the two ventricles in 11 patients with a biventricular heart who had undergone Fontan operation. Curves representing ventricular volume changes in a cardiac cycle measured on angiograms were smoothed and divided into 20 segments. We calculated the number of segments of the same directional volume changes (synchronous changes) between the two ventricles (synchronous ratio). We also calculated the total volume of the two ventricles (the two as one whole ventricle) by adding their volumes in each segment and calculated the ratio (stroke volume ratio) of the aortic stroke volume from the whole ventricle to the sum of stroke volumes of the morphological right and left ventricles. If the two ventricles ejected the blood in a completely synchronous manner, these ratios should be 1.0. In seven patients with synchronous ratios of 0.75 or greater and a stroke volume ratio of greater than 0.95, the cardiac index was 3.2 +/- 0.3 l/min/m2, the maximum total volume (corresponding to end-diastolic volume) was 106 +/- 45% normal, and the ejection fraction was 0.44 +/- 0.10. In four patients with ratios of less than 0.70 and 0.95, respectively, the parameters were 2.4 +/- 0.5 (P < 0.05), 193 +/- 92%, and 0.33 +/- 0.08, respectively. The synchronous ratio was inversely correlated with cardiac output. In conclusion, synchronism of the cardiac cycle of the two ventricles affects Fontan circulation in patients with a biventricular heart.

Adolescent↗
PubMed1994

A sibship with recurrent Kawasaki disease and coronary artery lesion.

Although epidemiologic studies of Kawasaki disease suggest an infectious etiology, the cause of this mysterious disease remains unclear. We describe the occurrence of five episodes of Kawasaki disease over a six-year period in three siblings. Two of the three children experienced recurrent Kawasaki disease and developed coronary artery lesions, which included giant coronary artery aneurysms in the youngest child. The non-contemporaneous occurrence of the disease in these three children emphasizes the importance of a genetic basis and/or environmental factors in the etiology of Kawasaki disease.

Child, Preschool↗
PubMed1994

Prediction of quality of life at long-term follow-up after Fontan operation by scoring risk factors.

Many factors will determine the quality of life at long-term follow-up after the Fontan operation. We tried to predict the long-term outcome of modified Fontan operation based on the combined assessment of various preoperative data. The preoperative condition was evaluated by a scoring system in which multilevel scores (from zero to 8 points) were given to a total of 14 morphological and physiological factors according to the contribution of each factor to mortality. The major factors were the association of the extracardiac total anomalous pulmonary venous connection, pulmonary arterial vascular resistance, mean pulmonary arterial pressure, PA index, ejection fraction of the main ventricle, and creatinine clearance. Points for each factor were determined according to surgical mortality, with zero points indicating no increased risk. The total score, i.e., the sum of the points for each item, in each patient was analyzed in relation to the patient's quality of life over a long-term follow-up, as evaluated by questionnaires. Twenty-six of 29 patients with scores of 5 or less showed normal or almost normal life long after the operation, whereas 5 of 10 with higher scores had restricted physical and daily activity. In conclusion, good preoperative condition predicts a good quality of life long after the Fontan operation. In addition, the concept of taking into account all possible risk factors as a comprehensive indicator may be useful in predicting long-term results.

Adolescent↗
PubMed1993

Phosphorylation of Ser-42 and Ser-59 in the N-terminal region of the tyrosine kinase p56lck.

Ser-42 and Ser-59 in the N-terminal region have been identified as the major phorbol ester-induced phosphorylation sites of p56lck. Phosphorylation of Ser-59 results in a gel shift from 56 kDa to 61 kDa. Simultaneous phosphorylation of Ser-42 and Ser-59 results in a further gel shift to 63 kDa. In vitro kinase assays show that Ser-59 can be uniquely phosphorylated by mitogen-activated protein kinase and that Ser-42 can be phosphorylated by either protein kinase A or protein kinase C.

Amino Acid Sequence↗
PubMed1993

Population aging and its health implications in Korea.

The author discusses the health implications of population aging in the Republic of Korea. "The aging of [the] Korean population, until recently, has remained in its early stage, and Korea is expected to enjoy 'a golden period' of lower age dependency ratio by the early 2020s. Accordingly, little attention has been focused on the health issues and problems associated with these demographic changes toward aging in Korea. But the changing demographic structure...will proceed with a relatively high tempo in the next decades.... Therefore it is stressed that 'the reserved years' of lower dependency, before population aging becomes a substantial public and private burden in Korean demographic context, must be fully utilized to formulate effective policies and counter-measures in health and welfare sectors, on which the greatest impacts of aging will fall." (SUMMARY IN KOR)

Age Distribution↗
PubMed1993

[The limits for modified Fontan operations with AV valve regurgitation--the effect of AV valve regurgitation on the Fontan operation for single ventricle].

We performed a modified Fontan operation on 14 patients of single ventricle with AV valve regurgitation (single right ventricle: SRV 8, single left ventricle: SLV 6) until 1990. During the same period, 41 patients of single ventricle without AV valve regurgitation underwent the modified Fontan operation. To evaluate the effect of AV valve regurgitation on the Fontan operation, operative mortality, ventricular and pulmonary functions were compared between two groups. No significant differences were observed in operative mortality (7% vs 12%). There were also no significant differences of post-operative cardiac index (mean 2.6 L/min/m2 vs 2.6 L/min/m2), pulmonary vascular resistance (mean 2.3 U.m2 vs 2.2 U.m2) and preoperative ejection fraction (mean 54% vs 62%) between two groups. Therefore, the hemodynamic status of single ventricle following the Fontan operation remained almost unchanged irrespective of the presence of AV valve regurgitation. This suggested that AV valve regurgitation was not itself a contraindication of the Fontan operation, if the correct indices and time for operation were selected.

Heart Atria↗
PubMed1992

Guanosine 5'-O-[S-(3-bromo-2-oxopropyl)]thiophosphate: a new reactive purine nucleotide analog labeling Met-169 and Tyr-262 in bovine liver glutamate dehydrogenase.

A new guanosine nucleotide has been synthesized and characterized: guanosine 5'-O-[S-(3-bromo-2-oxopropyl)]thiophosphate (GMPSBOP), with a reactive functional group which can be placed at a position equivalent to the pyrophosphate region of GTP. This new analog is negatively charged at neutral pH and is similar in size to GTP. GMPSBOP has been shown to react with bovine liver glutamate dehydrogenase with an incorporation of 2 mol of reagent/mol of subunit. The modification reaction desensitizes the enzyme to inhibition by GTP, activation by ADP, and inhibition by high concentrations of NADH, but does not affect the catalytic activity of the enzyme. The rate constant for reaction of GMPSBOP with the enzyme exhibits a nonlinear dependence on reagent concentration with KD = 75 microM. The addition to the reaction mixture of alpha-ketoglutarate, GTP, ADP, or NADH alone results in little decrease in the rate constant, but the combined addition of 5 mM NADH with 0.4 mM GTP or with 10 mM alpha-ketoglutarate reduces the reaction rate approximately 6-fold. GMPSBOP modifies peptides containing Met-169 and Tyr-262, of which Tyr-262 is not critical for the decreased sensitivity of the enzyme toward allosteric ligands. The presence of 0.4 mM GTP plus 5 mM NADH protects the enzyme against reaction at both Met-169 and Tyr-262, but yields enzyme with 1 mol of reagent incorporated/mol of subunit which is modified at an alternate site, Met-469. In the presence of 0.2 mM GTP + 0.1 mM NADH, protection against modification of Tyr-262, but only partial protection against labeling of Met-169, is observed. In contrast, the presence of 10 mM alpha-ketoglutarate + 5 mM NADH protect only against reaction with Met-169. The results suggest that GMPSBOP reacts at the GTP-dependent NADH regulatory site [Lark, R. H., & Colman, R. F. (1986) J. Biol. Chem. 261, 10659-10666] of bovine liver glutamate dehydrogenase, which markedly affects the sensitivity of the enzyme to GTP inhibition. The reaction of GMPSBOP with Met-169 is primarily responsible for the altered allosteric properties of the enzyme.

Affinity Labels↗
PubMed1992

Alteration of RNA I metabolism in a temperature-sensitive Escherichia coli rnpA mutant strain.

E. coli strain A49 carries the themosensitive mutation in the rnpA gene encoding the protein component of RNase P, a tRNA-processing enzyme. Two small RNAs were highly accumulated in the A49 carrying derivatives of ColE1-type plasmids, at nonpermissive temperature. Characterization of these RNAs showed that they were the processed or degraded products derived from RNA I, which is the negative controller of ColE1-type plasmid replication. These derivatives of RNA I only differ in size at the 5' ends. The data of their degradation and synthesis kinetics suggest that they are intermediates of RNA I metabolism.

Base Sequence↗
PubMed1991

Percutaneous transluminal coronary angioplasty for Kawasaki disease: a case report and literature review.

A 31-month-old boy developed right coronary artery stenosis after Kawasaki disease for which he underwent percutaneous transluminal coronary angioplasty (PTCA). The narrowing of the right coronary artery was successfully dilated by angioplasty without apparent complication. This case suggests that PTCA may have a potential advantage as a temporary method to postpone the aortocoronary bypass surgery in a child with coronary artery stenosis due to Kawasaki disease. However, strict patient selection is recommended for coronary angioplasty.

Angioplasty, Balloon, Coronary↗
PubMed1990

Receptor interconversion model of hormone action. 3. Estrogen receptor mediated repression of reporter gene activity in A431 cells.

The chicken estrogen receptor exists in three interconvertible forms, two of which bind estradiol with high affinity and one which lacks the capacity to bind estradiol. Interconversion is regulated by reactions involving ATP/Mg2+. By cotransfecting into A431 cells estrogen receptor cDNA in an expression vector together with the pA2 (-821/-87) tk-CAT vitellogenin construct, we demonstrate that constitutive expression of chloramphenicol acetyltransferase (CAT) activity can be regulated either by selection of ligand or by modifying phosphorylation reactions in the recipient cells. In the presence of estrogen receptors, constitutive expression of CAT activity is inhibited in three situations: (i) in the absence of an estrogenic ligand; (ii) in the presence of an anti-estrogen; and (iii) in the presence of an estrogenic ligand together with 12-O-tetradecanoylphorbol 13-acetate (TPA). Estrogen receptor mediated repression of constitutive CAT activity is not observed with the pA2 (-331/-87) tk-CAT construct, indicating that DNA sequences required for repression are located between -821 and -331 base pairs upstream of the transcription initiation site.

Animals↗
PubMed1990

Coronary artery calcification in Kawasaki disease.

To evaluate the angiographic features of coronary lesions in Kawasaki disease with coronary artery calcification, cinefluoroscopy and cineangiography were retrospectively reviewed in 116 patients who had undergone coronary angiography between 1982 and 1989. Angiographic abnormalities of coronary arteries were demonstrated in 55 of the 116 patients. In 5 (9.1%) of the 55 patients, 9 with calcification were identified by cinefluoroscopy and chest x-ray. Eight of the 9 calcified lesions showed a circular or ring-shape configuration. Coronary angiography revealed a total occlusion of the right coronary artery with collateral circulation from the distal left coronary artery in 2 patients and a severe stenosis of the right coronary artery in 2 patients, in whom anticoagulant therapy had not been continued during the follow-up periods. The remaining patient in whom anticoagulant therapy had been continued had bilateral aneurysms but no significant stenosis. These results indicate that a ring-shape calcification on chest x-ray in a patient with a history of Kawasaki disease may suggest an involvement by coronary artery stenosis even when anticoagulant drugs had been given. Therefore, coronary angiography should be performed to evaluate the stenotic lesions if this type of calcification is found by routine radiographic examination.

Adolescent↗
PubMed1990

[A bone metastasis of hepatocellular carcinoma].

Reported is a case of a bone metastasis of a hepatocellular carcinoma (HCC). A 61-year-old man with an unresectable HCC, which had been detected on spontaneous rupture, complained of a severe neck pain and numbness of both arms. A roentgenogram of the cervix showed destruction in the spinous process of the third cervical vertebra, and an MRI revealed a vertebral tumor compressing the spinal cord. Thus, the tumor was surgically removed. A pathological examination of the tumor revealed it to have the characteristic features on an HCC. One month after its removal, however, an iliac bone metastasis that was causing pain was found, and, again, an excision of the new tumor was performed. Pain symptoms disappeared after these operations. Treatment of an HCC bone metastasis is palliative, however, it is beneficial in maintaining the quality of the patient's remaining life.

Bone Neoplasms↗
PubMed1989

The cloned human oestrogen receptor contains a mutation which alters its hormone binding properties.

We demonstrate here that the human oestrogen receptor (hER) cDNA clone pOR8 obtained from MCF-7 cells contains an artefactual point mutation which results in the substitution of a valine for a glycine at amino acid position 400 (Gly-400----Val-400). This mutation in the hormone binding domain of the cloned hER destabilizes its structure and decreases its apparent affinity for oestradiol at 25 degrees C, but not at 4 degrees C, when compared with the wild-type hER with a Gly-400.

Base Sequence↗
PubMed1989

Clinical features of aortic arch anomaly with malalignment ventricular septal defect.

The clinical features and outcome after various surgical procedures on 9 patients with coarctation or interruption of the aortic arch and malalignment ventricular septal defect (group 1) were compared with those of 9 patients with the arch anomaly without malalignment ventricular septal defect (group 2). Cardiomegaly and metabolic acidosis were prominent in group 1. Five of the 9 patients in group 1 died in the immediate postoperative period (56% mortality), but no operative deaths occurred among 8 patients in group 2 (p less than 0.01). The ratio of left ventricular outflow tract to ascending aortic diameter was 0.59 +/- 0.09 in group 1 and 1.03 +/- 0.11 in group 2 (p less than 0.01). Three of 4 patients with a ratio of less than 0.6 died, but no operative deaths occurred among the 6 patients who had a palliative operation and in whom the ratio was more than 0.6. These data suggest that left ventricular outflow tract obstruction is critical when the ratio of left ventricular outflow tract to ascending aortic diameter is 0.6 or less. The presence of severe left ventricular outflow tract obstruction necessitates modification of the present surgical strategy.

Abnormalities, Multiple↗