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Biomedical subjects

I Y Kim

Publications and source records attributed to I Y Kim.

71 records · Page 4Linked to original sources
PubMed1993

Adult-onset pulmonary tuberculosis: findings on chest radiographs and CT scans.

Adult-onset pulmonary tuberculosis refers to primary tuberculous infection occurring initially in adults. The decreasing exposure in childhood, owing to careful public health measures and the advent of antituberculous chemotherapy, has resulted in later initial exposure to tuberculosis and an increased likelihood of susceptibility to tuberculosis during adulthood [1-3]. In addition, chest radiographs typically show a pattern more consistent with primary infection in pulmonary tuberculosis associated with AIDS. In this essay, we illustrate the spectrum of radiographic and CT findings of adult-onset pulmonary tuberculosis in patients without AIDS.

Adult↗
PubMed1992

Escherichia coli mutant SELD enzymes. The cysteine 17 residue is essential for selenophosphate formation from ATP and selenide.

Synthesis of a labile selenium donor compound, selenophosphate, from selenide and ATP by the Escherichia coli SELD enzyme was reported previously from this laboratory. From the gene sequence, SELD is a 37-kDa protein that contains 7 cysteine residues, 2 of which are located at positions 17 and 19 in the sequence -Gly-Ala-Cys-Gly-Cys-Lys-Ile- (Leinfelder, W., Forchhammer, K., Veprek, B., Zehelein, E., and Böck, A. (1990) Proc. Natl. Acad. Sci. U.S.A. 73, 543-547). Inactivation of the enzyme by alkylation with iodoacetamide indicated that at least 1 cysteine residue in the protein is essential for enzyme activity. To test the possibility that the Cys17 and/or Cys19 residue might be essential, these were changed to serine residues by site-specific mutagenesis. The biological activities of the wild type and mutant proteins were studied using E. coli MB08 (selD-) transformed with plasmids containing the selD genes. The plasmid containing the Cys17-mutated gene failed to complement MB08, whereas the Cys19-mutated gene was indistinguishable from wild type. The mutant proteins, like the wild type enzyme, bound to an ATP-agarose matrix, showing that their affinities for ATP were unimpaired. Selenide-dependent formation of AMP from ATP was abolished by mutation of Cys17, but the Cys19 mutation had no effect on the ability of the enzyme to catalyze the reaction. These results indicate that Cys17 has an essential role in the catalytic process that leads to the formation of selenophosphate from ATP and selenide.

Adenosine Triphosphate↗
PubMed1991

Computed tomographic findings of ruptured hepatic malignancy.

Massive hemorrhage from ruptured hepatocellular carcinoma is uncommon. We report our experience in three cases of ruptured hepatocellular carcinoma diagnosed by computed tomography (CT). CT was useful in detecting ruptured hepatocellular carcinoma showing the parenchymal tumor per se, defining the extent of the hematoma, and showing serial density changes with the age of the hematomas.

Carcinoma, Hepatocellular↗
PubMed1991

Tumours involving the intrathoracic vagus and phrenic nerves demonstrated by computed tomography: anatomical features.

Four cases of mediastinal tumours involving the intrathoracic vagus and phrenic nerves are presented and their computed tomographic (CT) features are described with particular attention to the intrathoracic course of these nerves. One case of mediastinal plexiform neurofibromatosis appeared as a series of low attenuation masses along the intrathoracic course of the nerves. Three examples of neurilemmomas of the vagus nerve appeared as masses with central low attenuation; one in the retrocaval area, one to the left of the aortic arch, and one in the right paraoesophageal area. Familiarity with the CT anatomy of the vagus and phrenic nerves will greatly assist in the diagnosis of mediastinal tumours.

Adolescent↗
PubMed1991

Development of a new moving-actuator type electromechanical total artificial heart.

A new type of electromechanical total artificial heart based on a moving-actuator mechanism was developed to decrease the total pump size and to improve the fitting characteristic of the pump to atrial remnants and arterial vessels. The blood pump consists of three major parts: right and left blood sacs and a moving pump actuator between two sacs. The total weight is 810 g and the volume of the pump is 770 ml. The actuator rolls back and forth on a circular track, producing alternating blood ejection. The pump performance was evaluated in mock circulation and animal implant experiments. The pump was implanted for 100 h in a calf (approximately 100 kg) with a stable hemodynamic state until accidental (electrical short circuit) death.

Animals↗
PubMed1991

Bronchovascular anatomy of the upper lobes: evaluation with thin-section CT.

The anatomy of the bronchovascular trees of the upper lobes was evaluated with thin-section computed tomography (CT) in 50 patients. In all patients, the subsegmental bronchi could be seen, except the right B2b, left B1 + 2c, and left B3c. Regular anatomic relationships were seen between the right A3b and B3b (A3b was seen along the medial aspect of B3b in 45 patients [90%]), right A2a and B2a (A2a was seen along the posteromedial aspect of B2a in 45 patients [90%]), and left A1 + 2c and B1 + 2c (A1 + 2c was seen along the posterior aspect of B1 + 2c in 41 patients [82%]). Four patterns of bronchial branching were seen in the left upper lobe. The lateral branch of the posterior segmental vein of the upper lobes was an anatomic landmark dividing the anterior and posterior segments of the upper lobes. Three kinds of venous drainage patterns were identified in both the right and left upper lobes.

Adolescent↗
PubMed1991

Lymphomatoid granulomatosis with isolated involvement of the brain--case report.

Lymphomatoid granulomatosis usually presents as a primary lung affliction with secondary metastatic spread to the central nervous system(CNS), and its initial manifestation purely as a CNS disease is rare. A 57-year-old man with histologically proven lymphomatoid granulomatosis of the brain as the sole manifestation of the disease is presented.

Brain Neoplasms↗
PubMed1990

A moving-actuator type electromechanical total artificial heart--Part I: Linear type and mock circulation experiments.

A new type of motor-driven total artificial heart system with a moving-actuator mechanism has been developed. The prototype system consists of a brushless dc motor inside of a rolling-cylinder, two arc-shaped pusher-plates and two polyurethane sacs. The moving-actuator type electromechanical pump has structural advantages of small size and light weight, as compared to other reported motor-driven pumps with fixed-actuator mechanisms. The results of the mock circulation tests are reported in this paper with a cardiac output of 9 L/min at an aortic pressure of 120 mmHg and a heart rate of 120 bpm. The fulfillment of the basic control requirements of the artificial heart was also confirmed, i.e., preload sensitive and afterload insensitive cardiac output response and balanced right and left ventricular outputs.

Algorithms↗
PubMed1985

Inactivation of S-adenosylhomocysteine hydrolase by nucleosides.

The irreversible inactivation of S-adenosylhomocysteine hydrolase purified from hamster and bovine liver by adenosine analogs substituted in the 5' and 2 positions has been investigated in detail. 5'-Cyano-5'-deoxyadenosine inactivates as potently as 9-beta-D-arabinofuranosyladenine (Ara-A). Substitution of the Ara-A at the 2 position by halogens or deleting N at the 3 position decreases its potency. Although weak, 2',3'-dideoxyadenosine can also inactivate the enzyme. The irreversible inactivation of the hydrolase in rat hepatocytes incubated with 2-chloroadenosine or 3-deaza-Ara-A could be demonstrated, concomitant with increases in 35S-labeled S-adenosylhomocysteine and S-adenosylmethionine in the hepatocytes.

Adenosine↗
PubMedDate not supplied

MR imaging of hepatic iron overload in rat.

To investigate the relationship of hepatic signal intensity and T2 with histologic grading in an animal model of oral iron overload and to determine the duration of feeding necessary to produce abnormalities detectable on magnetic resonance (MR) images, hepatic iron overload was induced in 12 rats by feeding them a diet supplemented with 4% carbonyl iron for 2-11 weeks. Iron overload seen on MR images was graded independently and blindly by two radiologists as normal, mild, moderate, or severe. The rats were killed, and histologic findings were graded blindly by four pathologists using a similar subjective scale. Hepatic T2 values were estimated from spin-echo images. In the rats with iron overload, intracellular iron deposition was noted on histologic studies. On MR images, hepatic signal intensity and T2 decreased after only 2 weeks of dietary iron overload, and both continued to decrease with longer duration of feeding. There was significant correlation between iron overload duration and changes on MR images and between MR images and histologic grading (r = .92, P = .0001 for both). The mean T2 of hepatic iron overload decreased with longer duration of feeding.

Animals↗
PubMedDate not supplied

Intraperitoneal seeding from hepatoma.

We report three cases of intraperitoneal seeding from hepatoma. Manifestation of intraperitoneal seeding from hepatoma were intraperitoneal masses (N = 2) and peritoneal thickening (N = 1). Main vascular feeder to intraperitoneal masses was omental branches of the gastroduodenal artery and/or the superior mesenteric artery.

Aged↗
PubMedDate not supplied

Gallbladder perforation: comparison of US findings with CT.

We compared the ultrasound (US) findings of gallbladder (GB) perforation with computed tomography (CT) in 13 patients with GB perforation confirmed at surgery. The common findings of GB perforation were pericholecystic fluid collection and layering of GB wall on US, pericholecystic fluid collection, streaky omentum or mesentery, and GB wall defect on CT. Pericholecystic fluid collection, layering of GB wall, and cholelithiasis were similarly detected on US or CT. GB wall defect and/or bulging of the GB wall suggested a site of perforation was revealed in five patients (38.5%) on US and nine (69.2%) on CT. CT further disclosed the findings of streaky omentum or mesentery (84.6%). CT was superior to US for diagnosis of GB perforation.

Adult↗
PubMedDate not supplied

Pancreatic carcinoid tumor with obstructive pancreatitis: multislice helical CT appearance: case report.

Carcinoid tumor of the pancreas is rare. Moreover, obstructive pancreatitis secondary to a pancreatic carcinoid tumor is extremely rare. We report a case of pancreatic carcinoid tumor in a 50-year-old male who presented with pancreatitis. On multislice helical computed tomography, the main pancreatic duct was obstructed by a small round tumor, and the main pancreatic duct proximal to the tumor was dilated. The correlation between the main pancreatic duct and the tumor was well depicted on minimum intensity projection image. This is the first report of multislice helical computed tomorgraphic and minimum intensity projection image findings of a pancreatic carcinoid tumor presenting with pancreatitis.

Carcinoid Tumor↗
PubMedDate not supplied

Ovarian hyperstimulation syndrome. US and CT appearances.

Ovarian hyperstimulation syndrome has been reported following induction of ovulation with drug therapy for infertility. The ultrasonic and computed tomographic (CT) appearances of the ovarian cystic enlargement is described. The role of ultrasound in this condition is diagnostic; the results of which are supported by CT.

Adult↗
PubMedDate not supplied

Ammonia removal using hepatoma cells in mammalian cell cultures.

It was examined whether hepatocyte cell lines can be used for ammonia removal in mammalian cell cultures. It was found that there exists a critical ammonium concentration level for each hepatocyte cell to remove ammonia. Among the cells tested in this work, primary hepatocytes showed the strongest ammonia removal capability if ammonium concentration is higher than the critical level. However, primary hepatocytes lost the liver function gradually and finally died after 2-3 weeks. Because of this limitation, primary hepatocytes were not appropriate to be used for ammonia removal in long-term cultures. Hep G2 cells, which are immortal, also showed a strong ammonia removal activity. The ammonia removal activity of Hep G2 cells depended on the concentration of ammonium in the medium, as in the case of primary hepatocytes. However, urea could not be detected in the course of ammonia removal by Hep G2 cells. Instead of urea, Hep G2 cells secreted glutamine into the culture medium. The capacity for ammonia removal was higher in the absence than in the presence of glutamine. Thus we checked the activity of glutamine synthetase in the Hep G2 cells. The level of glutamine synthetase activity increased with the addition of ammonium chloride. This result accounts for the ammonium concentration dependency of Hep G2 cells in ammonia removal and glutamine synthesis. Furthermore Hep G2 cells could grow well in the absence of glutamine, which was necessarily required in mammalian cell cultures. These results prove that glutamine formation serves as the primary mechanism of detoxifying ammonia in hepatocyte cell lines as expected. In addition, it was demonstrated that ammonium level could be reduced 38% and that erythropoietin production increased 2-fold in the mixed culture of Hep G2 and recombinant CHO cells.

Ammonia↗