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Biomedical subjects

K C Cho

Publications and source records attributed to K C Cho.

15 recordsLinked to original sources
PubMed1991

Air in the fissure for the ligamentum teres: new sign of intraperitoneal air on plain radiographs.

In each of four patients in whom an acute spontaneous pneumoperitoneum developed, a vertically directed area of hyperlucency in the right upper quadrant was seen on radiographs of the abdomen obtained with the patient supine. This finding, which appeared in the absence of other characteristic signs of free air on plain radiographs and which, to the authors' knowledge, has not been previously recognized, represented intraperitoneal gas confined to the fissure for the ligamentum teres (FLT). The location of the hyperlucent area was confirmed with computed tomography or laparotomy in each patient. The distinctive configuration of air in the FLT is a subtle but reliable indicator of pneumoperitoneum.

Aged↗
PubMed1991

Bowel obstruction: evaluation with CT.

Eighty-four computed tomographic (CT) scans from patients referred for bowel obstruction between January 2, 1988, and December 31, 1989, were retrospectively evaluated. A pair of radiologists without knowledge of patient histories determined the presence or absence of bowel obstruction. Sixty-four patients ultimately proved to have intestinal obstruction, and 20 did not. Diagnosis was established by means of surgery (n = 39), barium studies (n = 17), and clinical course (n = 28). Causes of obstruction included adhesions (n = 37), metastases (n = 6), primary tumor (n = 7), Crohn disease (n = 4), hernia (n = 3), hematoma (n = 2), colonic diverticulitis (n = 2), and other (n = 3). In addition, 83 CT examinations in patients with no history or indication of intestinal obstruction were simultaneously reviewed. The overall sensitivity was 94%, specificity was 96%, and accuracy was 95%. The cause of obstruction was correctly predicted in 47 of 64 cases (73%). Intestinal obstruction was not diagnosed in any of the 83 control patients. CT is most useful in patients with a history of abdominal malignancy and in patients who have not been operated on and who have signs of infection, bowel infarction, or a palpable abdominal mass.

Barium Sulfate↗
PubMed1990

Comparison of computed tomography and contrast enema evaluation of diverticulitis.

A total of 31 patients with diverticulitis were analyzed who had both computed tomography and contrast enema. There was almost equal sensitivity to abnormality of approximately 90 percent. Contrast enema produced a specific diagnosis of diverticulitis in 61 percent, using stringent positive criteria, and an additional 29 percent with suggestive findings. Comparative computed tomography specific diagnoses in those 31 cases was made in 65 percent, and suggestive in 23 percent. Computed tomography was particularly useful diagnostically in cases of retrograde obstruction on contrast enema. The authors conclude that contrast enema should be the primary mode of approach, while computed tomography can be a valuable follow-up when the diagnosis is still in doubt, or if it is possible that patient management might be altered by additional information.

Barium Sulfate↗
PubMed1990

Sigmoid diverticulitis: diagnostic role of CT--comparison with barium enema studies.

The diagnostic value of computed tomography (CT) and barium enema (BE) studies was evaluated prospectively in hospitalized patients with the presumptive diagnosis of acute sigmoid diverticulitis based on the presence of left-lower-quadrant pain and tenderness, fever, and leukocytosis. Of 56 patients, 11 had sigmoid diverticulitis confirmed at surgery and 16 by clinical response to medical therapy. CT, performed in all diverticulitis patients, had positive results in 93% (25 of 27). These compared favorably with BE study results, of which 80% (20 of 25) were positive. Neither examination had false-positive results. In the 29 patients who did not have diverticulitis, an alternative diagnosis was made by means of CT in 20, but in only three by means of BE studies. Many of the extracolonic abnormalities recognized at CT were clinically unexpected and necessitated emergency surgery. The excellent sensitivity and specificity of CT coupled with its versatility in the detection of extracolonic disease give it an advantage over contrast enema studies for diagnosis of sigmoid diverticulitis. CT should be the initial study in acutely ill patients, especially when the clinical features are atypical for sigmoid diverticulitis.

Acute Disease↗
PubMed1989

Electron transfer between cytochrome c and metal hexacyanide complexes. Effect of thermodynamic driving force on the electron transfer rate.

The electron transfer reactions between ferrocytochrome c and three isomorphic hexacyanide complexes, [Fe(CN)6]3-, [Os(CN)6]3- and [Ru(CN)6]3-, have been studied using the method of photoexcitation. The transfer rates for [Os(CN)6]3- and [Ru(CN)6]3- are, respectively, about 45- and 200-times higher than that of [Fe(CN)6]3-. A reorganization energy of approx. 0.8 eV was found for the cytochrome c-hexacyanide system when the data were analyzed according to the theory of Marcus.

Cyanides↗
PubMed1989

Terminal ileitis associated with cytomegalovirus and the acquired immune deficiency syndrome.

A 41-yr-old homosexual male had cytomegalovirus infection localized to the terminal ileum as his initial and sole evident opportunistic infection due to the acquired immune deficiency syndrome. The symptoms, signs, roentgenographic findings, and appearance at surgery were suggestive of Crohn's disease. The pathogen was identified only by microscopic examination of bowel resected during a second laparotomy. The terminal ileum had profound mucosal ulceration and transmural fibrosis without granulomas. This novel report suggests that cytomegalovirus infection should be carefully searched for in immunocompromised patients presenting with clinical features suggesting Crohn's disease.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Kinetics of electron transfer between cytochrome c and iron hexacyanides. Evidence for two electron-transfer sites.

The electron-transfer reaction between ferrocytochrome c and ferricyanide has been studied by the method of photoexcitation. The observed transfer rate shows saturation behaviour at high ferricyanide concentration. Data analysis indicates that there are two binding sites of vastly different affinities at which electron transfer occurs. The binding constant for the strong binding site decreases from 1600 M-1 to 80 M-1 as the ionic strength increases from 15 mM to 140 mM. At 20 degrees C, the intramolecular electron-transfer rate for this site is 4.65 X 10(4) s-1, which gives an electron-transfer distance of approx. 9.7 A according to Hopfield's model.

Animals↗
PubMed1988

Radiologic evaluation of pancreatic ascites.

Two cases of pancreatic ascites are presented in which preoperative endoscopic retrograde pancreatography (ERP) precisely identified the exact location of the leakage of pancreatic juice into the peritoneal cavity. Computed tomography was not helpful in either case. Endoscopic retrograde pancreatography is the most valuable imaging examination to confirm the diagnosis of pancreatic ascites and to direct surgical management.

Aged↗
PubMed1987

Cytomegalovirus esophagitis in AIDS: radiographic features in 16 patients.

Cytomegalovirus is one of the more common opportunistic organisms implicated in the development of esophagitis in patients with AIDS. A review of the radiographic features of 16 proved cases of cytomegalovirus esophagitis showed a spectrum of abnormalities related to the severity of the inflammatory process. Seven patients had a mild form of esophagitis with segmental involvement characterized by granular mucosa, superficial erosions, and poorly defined, shallow ulcerations. Nine patients had more severe esophagitis with solitary or multiple deep ulcers and a background of normal mucosa. The deep ulcerations were oval in shape and varied in size. Some projected intraluminally and had a thin rim of radiolucency at the base. Short-term follow-up examinations showed progression of the disease in four patients, no change in one patient, and regression without specific therapy in one patient. Although these radiographic features are highly suggestive of cytomegalovirus esophagitis, the diagnosis requires histologic confirmation.

Acquired Immunodeficiency Syndrome↗
PubMed1979

Spin equilibrium and quaternary structure change in hemoglobin A. Experiments on a quantitative probe of the stereochemical mechanism of hemoglobin cooperativity.

The molecular mechanism of hemoglobin cooperativity was studied kinetically by flash photolysis on mixed-state hemoglobins which consist of three ferrous carboxy subunits and one hybrid ferric subunit including fluoromet, azidomet, cyanatomet, and thiocyanatomet. The effects of conformational transitions on the hybrid subunit were detected by kinetic absorption spectroscopy after the CO was fully photodissociated from the binding sites by a large pulse of light from a tunable dye laser. The hemoglobin conformational transition rate was observed to depend on its state of ligation. At 22 degrees C, pH 7, and 0.1 M phosphate, the deoxy R yields T conformational change rate is 4 x 10(4)s-1. The rate decreases to 1.4 x 10(4)s-1 for singly ligated hemoglobin. The R yields T conformation change alters the energy separation between high- and low-spin states for azidomet, cyanatomet, and thiocyanatomet subunits by about 700, 300, and 300 cal/mol, respectively. There are two possible implications of this result: (1) the iron atom spin state is not the only major factor in the determination of its position with respect to the heme plane or (2) the change with conformation of the protein force exerted by the proximal histidine on the iron atom (for an iron to heme-plane displacement of less than 0.3 A) is less than 50% of that expected from simple models in which this motion is responsible for cooperativity.

Azides↗
PubMedDate not supplied

Closed-loop obstruction of the small bowel: CT and sonographic appearance.

Two patients with closed loop obstruction diagnosed by CT and sonography are reported. Abdominal radiograph was nonspecific. The characteristic CT and sonographic features included (a) isolated conglomerate of dilated, fluid-filled bowel loops; (b) fixation of these "U" shaped distended loops; (c) thickened bowel wall; and (d) extraluminal fluid.

Adult↗
PubMedDate not supplied

CT appearance in tuberculous pancreatic abscess.

We report a case of a tuberculous pancreatic abscess in a 47-year-old human immunodeficiency virus positive intravenous drug abuser. She had a prolonged febrile course and persistent abdominal pain. On CT and sonography the lesion lacked the usual ancillary features of an abscess such as diffuse pancreatic enlargement and a peripancreatic fluid collection, and more closely resembled a necrotic neoplasm.

Abscess↗