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Biomedical subjects

E E Kim

Publications and source records attributed to E E Kim.

At least 19 recordsLinked to original sources
PubMed1992

Refinement of the crystal structure of ribonuclease S. Comparison with and between the various ribonuclease A structures.

Ribonuclease S (RNase-S) is a complex that consists of two proteolytic fragments of bovine pancreatic ribonuclease A (RNase-A): the S-peptide (residues 1-20) and S-protein (residues 21-124). We have refined the crystal structures of three RNase-S complexes. The first two contain the full-length 20-residue S-peptide and were studied at pHs of 4.75 and 5.5. The third one consists of a truncated form of S-peptide (residues 1-15) and was studied at pH 4.75 as the reference structure for a series of mutant peptide complexes to be reported separately. Excluding residues 16-23 which are either missing (in the S15 complex) or disordered (in both S20 complexes), all three structures refined at 1.6-A resolution are identical within the estimated errors in the coordinates (0.048 A for the backbone atoms). The R-values, residual error, range from 17.4% to 18.6%. The final model of S20, pH 4.75, includes 1 sulfate and 84 water molecules. The side chains of 11 residues were modeled in two discrete conformations. The final structures were independent of the particular RNase-A or RNase-S used as a starting model. An extensive comparison with refined crystal structures of RNase-A reveals that the core of the molecule which is held together with extensive hydrogen bonds is in identical pattern in all cases. However, the loop regions vary from one structure to another and are often characterized by high B-factors. The pattern of thermal parameters appears to be dependent on crystal packing and correlates well with the accessibility calculated in the crystal. Gln60 is a conserved residue in all sequences known to date for this class of ribonucleases. However, it is the only residue that is clearly defined in an unfavorable position (phi = -100 degrees, psi = -130 degrees) on the Ramachandran plot. The origin of the substantial differences between RNase-A and RNase-S in stability to both acid and temperature denaturation and in susceptibility to proteolysis at neutral pH is not obvious in our visual comparison of these two structures.

Animals↗
PubMed1992

Evaluation of sensitivity and specificity of upper extremity radionuclide venography in cancer patients with indwelling central venous catheters.

Two hundred twenty upper extremity radionuclide venograms were performed using upper extremity injection of 5 mCi of Tc-99m DTPA in each arm of patients with indwelling central lines. Evidence of obstruction was found in 123 patients, collateral flow without anatomic obstruction in six patients, and a slow-flow pattern in 12 patients. Twenty-six of these also underwent upper extremity contrast venography within 48 hours of the scan. Contrast venograms and radionuclide venograms agreed in 19 patients (16 correctly identified as obstructed, three correctly identified as unobstructed). Six patients showed the slow-flow pattern without collaterals or obstruction. Subsequently, six follow-up contrast studies showed no evidence of obstruction or collaterals. The authors conclude that obstruction with collateral flow on radionuclide venograms correctly predicts obstruction. However, the slow-flow pattern does not and should not be used as the sole criterion to diagnose partial obstruction.

Arm↗
PubMed1992

Differentiation of residual or recurrent tumors from post-treatment changes with F-18 FDG PET.

Positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (FDG) was used to differentiate recurrent or residual malignant disease from the effects of cancer treatment. Transaxial images were obtained after injection of 5-10 mCi (185-370 MBq) of F-18 FDG in 68 patients (including 33 with brain tumors) whose posttreatment computed tomographic (CT) or magnetic resonance (MR) imaging findings had been suggestive of malignant disease. PET findings were correlated with surgical results in 18 patients and with the outcomes of CT, MR imaging, clinical, and laboratory 9-month follow-up studies in 50 patients. There was good agreement between F-18 FDG uptake and presence or absence of malignant disease except in four cases of brain tumors in which histologic findings could not be correlated with biologic behavior. The putative sensitivity and specificity in the 33 cases of brain tumors were 80% and 94%, respectively. The authors conclude that PET with F-18 FDG is useful in detection of previously treated metabolically active tumors but is limited in diagnosis of recurrent microscopic or metabolically inactive tumors.

Abdominal Neoplasms↗
PubMed1992

SPECT in the evaluation of cancer patients: not quo vadis; rather, ibi fere summus.

In the past 7 years, single photon emission computed tomography (SPECT) has evolved from an interesting nuclear medicine technique rarely performed because of technical difficulties into a valuable clinical tool in the management of cancer cases. The development of stable multidetector instruments with collimators and gantries specifically designed for SPECT and the introduction of new radiopharmaceuticals recently approved by the U.S. Food and Drug Administration have rapidly moved SPECT from the field of clinical investigation to clinical practice. SPECT is a valuable addition to other tomographic modalities capable of displaying the physiology of disease as well as anatomy. In this work the authors describe the role of SPECT in a cancer center and, in particular, how they use it to solve clinical problems. They also review the published literature, when appropriate. The authors have found SPECT of particular value in evaluation of myocardial ischemia, in differentiating tumor recurrence from posttherapy changes in the lymphomas, in tumor diagnosis and surveillance, and in separating hemangioma from malignant lesions in the liver.

Abdomen↗
PubMed1992

Multiple myeloma: spinal MR imaging in patients with untreated newly diagnosed disease.

Spinal magnetic resonance (MR) imaging was performed in 29 patients with newly diagnosed, untreated multiple myeloma. Nineteen (66%) patients were asymptomatic. Sagittal pre- and postcontrast T1-weighted spin-echo images and gradient-recalled-echo images of the thoracic and lumbosacral spine were obtained. Marrow involvement was identified in 20 (69%) patients. There were three MR patterns: focal lesions in nine patients (31%), diffuse involvement in seven (24%), and an inhomogeneous pattern of tiny lesions on a background of normal marrow in four (14%). A statistically significant correlation between MR imaging patterns of marrow involvement and serum hemoglobin values (one-way, P = .0899; Kruskal-Wallis, P = .0620) and between MR imaging patterns and percentage of marrow plasmacytosis (Kruskal-Wallis, P = .0314) was noted, with patterns of diffuse and focal marrow involvement associated with more abnormal values. Spinal MR imaging in patients with early myeloma may reveal marrow involvement in both symptomatic and asymptomatic patients. Some correlation was found between MR imaging patterns and laboratory indexes of disease.

Adult↗
PubMed1991

Bacillus subtilis alkaline phosphatases III and IV. Cloning, sequencing, and comparisons of deduced amino acid sequence with Escherichia coli alkaline phosphatase three-dimensional structure.

Bacillus subtilis has an alkaline phosphatase multigene family. Two members of this gene family, phoAIII and phoAIV, were cloned, taking advantage of in vitro constructed strains containing a plasmid insertion within one or the other of the structural genes. The DNA sequences of the two genes showed approximately 64% identity at the DNA level and 63% identity in the deduced primary amino acid sequences. The phoAIII and phoAIV genes code for predicted proteins of 47,149 and 45,935 Da, respectively. Comparison of the deduced primary amino acid sequence of the mature proteins with other sequenced alkaline phosphatases from Escherichia coli, yeast, and humans shows 25-30% identity. Based on the refined crystal structure of E. coli alkaline phosphatase, it appears that the active site and the core of the structure are retained in both Bacillus alkaline phosphatases. However, both proteins are truncated at the amino terminus compared with other mature alkaline phosphatases, three sizable surface loops of E. coli are deleted, and a minidomain is replaced with a larger domain in the model. Neither Bacillus alkaline phosphatase sequenced contains any cysteine residues, an amino acid implicated in intrachain disulfide bond formation in other alkaline phosphatases.

Alkaline Phosphatase↗
PubMed1991

Case report 682. Neuroepithelioma of soft tissues of the knee.

Peripheral neuroepitheliomas should be included in the differential diagnosis of a soft-tissue tumor in the extremities or chest wall, especially in young adolescents. MRI provides useful information as to the extent of the tumor and relationship with adjacent structures, although it may not differentiate neuroepitheliomas from other, more common, soft-tissue sarcomas. Together with clinical and histological findings, MRI can assist in the diagnosis and treatment planning of this tumor.

Adolescent↗
PubMed1991

Reusable gels for germanium-68 sources.

Two water-soluble gels, gelatin and Carbowax, were mixed with radioactive 68Ge solutions and evaluated for their use as long-lived (half-life, 280 days) radioactive sources. These gels melt at 40-50 degrees C and solidify at room temperature. The amount of 68Ge mixed with them can be increased or decreased as needed, eliminating waste of 68Ge. These gel sources also may replace short-lived 68Ga (half-life 68 min) as attenuation correction sources in positron emission tomography (PET) and reduce frequency of source preparation, thus reducing exposure of PET operators to radiation.

Gelatin↗
PubMed1991

Soft-tissue sarcoma: MR imaging vs sonography for detection of local recurrence after surgery.

To determine the value of MR and sonography in detecting local recurrences of soft-tissue sarcomas after surgery, 26 MR and sonographic studies performed in 21 patients were reviewed retrospectively. Recurrences were confirmed histologically in 12 (46%) of 26 studies. The MR images and sonograms were obtained within 1 month of each other. The findings were classified as recurrence, no recurrence, or indeterminate. Sonography was instrumental in guiding fine-needle aspiration biopsy of impalpable lesions. In two cases, the findings on sonography were indeterminate. In both of these cases, the sonograms had been obtained soon after surgery (at 2 and 4 months). The sensitivity and specificity in the detection of local recurrences were 83% and 93%, respectively, for MR and 100% and 79%, respectively, for sonography. These differences were not statistically significant. We conclude that MR and sonography appear to be equally useful in the detection of local recurrences of soft-tissue sarcomas, sonography can be used for routine follow-up and in guiding needle biopsies, sonography may be more difficult to interpret than MR during the early postoperative period, and MR should be used if sonography is inconclusive.

Adolescent↗
PubMed1979

Sensitivity of radionuclide brain scan and computed tomography in early detection of viral meningoencephalitis.

The sensitivity of radionuclide imaging and computed tomography (CT) was evaluated in 25 patients for early detection of viral meningoencephalitis. Diagnosis was based on clinical evidence, cerebrospinal fluid (CSF) studies, electroencephalography (EEG) and radionuclide imaging. Computed tomography with contrast enhancement was performed within four days after onset of neurological signs or symptoms in 23 patients; no significant findings such as low-absorption abnormalities, mass effect or abnormal enhancement were seen. Radionuclide imaging demonstrated a sensitivity of 90% in the detection of viral meningoencephalitis; the temporal lobe was most commonly involved in patients with herpes encephalitis. Radionuclide imaging should be considered as the first diagnostic procedure in suspected early viral meningoencephalitis.

Adolescent↗
PubMed1979

Acute hemiplegia of childhood.

Acute hemiplegia of childhood is briefly reviewed with examples of various etiologies. The role of brain scans in diagnosing and following children with this syndrome is emphasized. Cerebral angiography and computer tomography represent complementary examinations in the evaluation of these patients.

Acute Disease↗
PubMed1979

Role of radionuclide joint imaging in high tibial osteotomy.

The importance of a preoperative bone scan before tibial osteotomy is to detect the extent of specific compartmental involvement of the osteoarthritic knee. It is not necessary to obtain a bone scan in every case, but when difficulty arises in the selection of patients for surgery, whether the opposite compartment is involved by disease or not, a preoperative bone scan becomes useful and may eliminate the need for other procedures such as arthroscopy and arthrotomy. In a series of cases of osteotomy in 21 knees of 22 patients, with an average follow-up of 15 months, all had a preoperative bone scan, 14 repeated postoperatively. Satisfactory functional results were obtained in 71%.

Adult↗
PubMed1979

Axillary lymphoscintigraphy by radioimmunodetection of carcinoembryonic antigen in breast cancer.

In seven women with carcinoma of the breast I-131-labeled antibodies to carcinoembryonic antigen (CEA) were administered subcutaneously in the finger webs. Subsequent scintigraphic immages demonstrated localization of radioactivity in the ipsilateral axillary metastases of all patients and in the contralateral axillae of three. Fifteen patients with either gastrointestinal or genitourinary cancers were studied as controls; in 12 both the hands and feet were injected with antibodies to CEA and in the other three either the hands or feet. Radioactivity was observed in the inquinal nodes of four control patients with tumors below the diaphragm and in the axillary nodes of one patient with a tumor above the diaphragm. The concentration of antibody in lymph node metastases from breast carcinoma was 100% specific. In those lymph nodes that presumably contained no metastatic tumor but demonstrated localization of labeled antibody, retention of CEA in the nodes from tumor drainage is postulated as the receptor site for the antibody.

Aged↗
PubMed1978

Substernal thyroid carcinoma detected by 67Ga scan in a patient with normal 131I scan.

A patient with a superior mediastinal mass on an admission chest radiograph was initially evaluated by an 131I thyroid scan which failed to demonstrate a substernal thyroid. However, the tomographic 67Ga scan clearly showed an abnormal uptake in the area corresponding to the mass lesion on radiographic examination. Subsequent resection and biopsy of the substernal mass revealed a poorly differentiated follicular carcinoma with foci of anaplastic carcinoma. The differential diagnosis of the anterior mediastinal mass and the usefullness of the tomographic gallium scan are briefly discussed.

Adenocarcinoma↗