Search PubMed⌕ Search

Biomedical subjects

S Kim

Publications and source records attributed to S Kim.

At least 1,171 records · Page 65Linked to original sources
PubMed1991

Paroxysmal nocturnal hemoglobinuria. Case report of MR imaging and CT findings.

A case of paroxysmal nocturnal hemoglobinuria (PNH) is presented in which MR imaging and CT findings were characteristic. The signal intensity of renal cortex was lower than that of medulla on both T1- and T2-weighted imaging. On CT without contrast enhancement the attenuation of renal cortex was higher than that of renal medulla. These findings at MR imaging and CT were the results of a deposition of hemosiderin in the cells of proximal convoluted tubules, and were helpful for diagnosis of PNH.

Female↗
PubMed1991

The automated interview versus the personal interview. Do patient responses to preoperative health questions differ?

Laboratory testing of presurgical patients has been shown to be excessive, thereby increasing costs, reducing resources for other health care uses, and increasing risks to both patients and physicians. As one step toward reducing the number of unnecessary preoperative tests ordered, we used an automated method to aid preoperative assessment of 239 patients in Chicago and in Winnipeg. The "HealthQuiz," a small hand-held device containing a computer chip and video screen, uses a decision tree to ask a minimum of 60 health-related questions (the patient's response to certain questions determines the number of questions presented). The device then generates a summary printout of patient answers, the health areas needing further attention, and the laboratory tests most likely to uncover clinically important abnormalities in that patient. HealthQuiz responses are intended to aid the physician and not to replace the personal interview. As an aid, the automated interview highlights possible problem areas for in-depth pursuit by the physician. The need for nonselective batteries of tests is eliminated because recommendations for tests are based on specific elements of a patient's history. To be effective, responses to the HealthQuiz should be the same as responses to similar questions asked by a physician. We tested that premise in this study. Patient's answers to the HealthQuiz were compared with their responses to a randomly selected set of the same questions in a personal interview. Ninety-seven percent of the response pairs were identical, and most of the 3% that differed involved changes from "not sure" replies to the HealthQuiz. Laboratory tests suggested by responses to the two methods of questioning did not differ.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Intraperitoneal cisplatin-based chemotherapy for ovarian carcinoma.

Ovarian carcinoma demonstrates a steep dose-response curve for cisplatin, but even very small levels of acquired resistance at the cellular level are sufficient to block the efficacy of intravenous (IV) cisplatin. The intraperitoneal (IP) route of administration produces a 12-fold to 15-fold greater exposure for the peritoneal cavity, and concurrent use of IV thiosulfate permits the safe IP injection of 200 mg/m2 cisplatin. In this study, two phase II trials of an IP regimen containing cisplatin 200 mg/m2 and etoposide 350 mg/m2 with IV thiosulfate were conducted; the first trial enrolled patients with residual disease less than 2 cm who had failed primary cisplatin-based IV chemotherapy and the second trial newly diagnosed ovarian carcinoma patients irrespective of the size of residual disease after primary surgery. As salvage therapy, the IP cisplatin/etoposide regimen produced a median survival of 26 months from the start of IP therapy and 51 months from diagnosis. As first-line therapy, the median survival has not yet been reached; projected survival is 68% at 27 months. In both studies the major toxicity was myelosuppression; the use of concurrent thiosulfate almost completely eliminated serious nephrotoxicity and neurotoxicity. The size of the largest tumor mass was an important determinant of efficacy in both settings. The results of these trials are consistent with the hypothesis that increased drug delivery will result in higher response rates and improved survival. Data are sufficiently encouraging to mandate phase III randomized trials of this program.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Comparative study of cutaneous T-cell lymphoma and adult T-cell leukemia/lymphoma. Clinical, histopathologic, and immunohistochemical analyses.

An important disease entity distinct from cutaneous T-cell lymphoma (CTCL) in Japan is adult T-cell leukemia/lymphoma (ATL), which usually shows the same phenotype as CTCL, i.e., a helper/inducer T-cell phenotype (CD4+CD8-), and usually involves the skin. Clinically, both CTCL and ATL are heterogeneous in nature. In this study, we demonstrated differences between CTCL and ATL in terms of clinical and immunopathologic cell surface features. In patients with ATL, the predominant clinical findings were peripheral lymph node involvement, skin lesions, hepatosplenomegaly, leukemic manifestations, and an aggressive course. In patients with CTCL, by contrast, only skin lesions predominated at the onset of the disease and a relatively good prognosis was demonstrated. Phenotypic heterogeneity of ATL in the skin, i.e., CD4-CD8-, CD4+CD8-, and CD4-CD8+, was demonstrated. Expression of Leu8, CD7 (Leu9), and CD45RA (2H4) was high in both the skin-infiltrating ATL cells and peripheral blood and lymph node ATL cells compared with that in the skin-infiltrating CTCL cells. Expression of CD25 (IL-2R), CD71 (OKT9), HLA-DR, and HLA-DQ was higher in the skin-infiltrating ATL cells than in CTCL cells. Expression of CD29 (4B4) was high, and that of CD45RA (2H4) was low in both the skin-infiltrating ATL and CTCL cells compared with the peripheral blood and lymph node ATL cells. Expression of CD45RO (UCHL-1) was not significantly high in the skin-infiltrating CTCL cells compared with that in ATL cells. The most significant phenotypic difference between ATL cells and CTCL cells was the expression of Leu8 (lymph node homing receptor), CD7 and CD25 antigens on the cell surface, and the main phenotypic difference between skin-infiltrating ATL and CTCL cells and peripheral blood and lymph node ATL cells was the expression of CD29 and CD45RA. These findings confirm that the difference in antigen expression on the cell surface might reflect the clinical features of ATL and CTCL, and suggest that the predominant phenotype of peripheral blood and lymph node ATL cells is that of naive, relatively immature or activated T-cells, and that CTCL cells are previously activated (memory) T-cells. In other words, CTCL cells do not share the same origin as ATL cells. These observations support the concept that ATL is a disease distinct from CTCL.

Adolescent↗
PubMed1990

Mapping of a higher order protein-DNA complex: two kinds of long-range interactions in lambda attL.

To map the protein-protein and protein-DNA interactions involved in lambda site-specific recombination, Int cleavage assays with suicide substrates, nuclease protection patterns, gel retardation experiments, and quantitative Western blotting were applied to wild-type attL and attL mutants. The results lead to a model in which one IHF molecule bends the attL DNA and forms a higher order complex with the three bivalent Int molecules required for excisive recombination. It is proposed that each of the Int molecules binds in a unique manner: one bridges two DNA binding sites in cis, one is held via its high affinity amino-terminal DNA binding domain, and the third depends upon protein-protein interactions in addition to its low affinity carboxy-terminal DNA binding domain. This protein-DNA complex contains two unsatisfied DNA binding domains, each with a different sequence specificity, and is well suited to specific interactions with an appropriate recombination partner.

Bacteriophage lambda↗
PubMed1990

Radiation hybrid mapping: a somatic cell genetic method for constructing high-resolution maps of mammalian chromosomes.

Radiation hybrid (RH) mapping, a somatic cell genetic technique, was developed as a general approach for constructing long-range maps of mammalian chromosomes. This statistical method depends on x-ray breakage of chromosomes to determine the distances between DNA markers, as well as their order on the chromosome. In addition, the method allows the relative likelihoods of alternative marker orders to be determined. The RH procedure was used to map 14 DNA probes from a region of human chromosome 21 spanning 20 megabase pairs. The map was confirmed by pulsed-field gel electrophoretic analysis. The results demonstrate the effectiveness of RH mapping for constructing high-resolution, contiguous maps of mammalian chromosomes.

Animals↗
PubMed1990

[Effects of sampling bandwidth in MR imaging].

Phantom and volunteer study was performed with spin-echo sequences of different sampling bandwidths to evaluate the narrow bandwidth signal acquisition technique. Our results demonstrated the characteristics of the narrow bandwidth sequence as follows: SNR improvement, sensitive to the field inhomogeneity and motion, loss of edge definition for short T2 tissues, and prominent chemical shift artifacts. Narrow bandwidth sequence with flow compensation was suitable for brain T2 weighted images because of its high SNR and less artifacts. In spite of the improvement of SNR, the narrow bandwidth technique may be inappropriate for short T2 tissues such as muscle, because of prominent chemical shift artifacts and loss of edge definition. Consequently, sampling bandwidth is one of the parameters which can be manipulated to improve MR image quality.

Brain↗
PubMed1990

Localization and subcellular distribution of smg p25A, a ras p21-like GTP-binding protein, in rat brain.

We have made a monoclonal antibody which specifically recognizes smg p25A among many ras p21/ras p21-like GTP-binding proteins thus far purified from bovine brain membranes. By use of this antibody, we have investigated the localization and subcellular distribution of smg p25A in rat brain by light and electron microscopic immunocytochemistry and by immunoblotting. By light microscopic immunocytochemistry, specific immunoreactivity is widely distributed, most abundant in neuropil, weak in neuronal somata, and absent from white matter. By electron microscopic immunocytochemistry, intense labeling is demonstrated on most of the synapses and concentrated in the presynaptic area where synaptic vesicles are observed. Presynaptic plasma membranes are weakly labeled but mitochondria, postsynaptic plasma membranes, and postsynaptic densities are unlabeled. In subcellular fractionation analysis of cerebrum, about one-fifth of smg p25A is found in the soluble cytosol fraction and the rest is found in the particulate fraction. About half of the particulate-bound smg p25A is recovered in the P2 fraction containing synaptosomes, mitochondria, and myelin, among which a major portion of smg p25A is recovered in the synaptosomal fraction. In the synaptosomal fraction, smg p25A is concentrated about 8-fold in the fraction containing synaptic vesicles and about 3-fold in the fraction containing synaptic plasma membranes compared with the original homogenate. smg p25A is present at a low level in the fraction containing synaptosomal soluble substances but almost absent from the fractions containing intrasynaptosomal mitochondria or post-synaptic densities. These results suggest that smg p25A plays important roles in the regulation of synaptic functions such as exo-endocytotic recycling of synaptic vesicles during neurotransmitter release.

Animals↗
PubMed1990

[A short TE gradient-echo sequence using asymmetric sampling].

We have developed a gradient-echo pulse sequence with a short TE less than 4 msec using a data set of asymmetric off-center sampling with a broad bandwidth. The use of such a short TE significantly reduces T2* de-phasing effect even in a two-dimensional mode, and by collecting an off-center echo, motion-induced phase dispersion is also considerably decreased. High immunity of this sequence to these dephasing effects permits clear visualization of anatomical details near the skull base where large local field inhomogeneities and rapid blood flow such as in the internal carotid artery are present.

Brain↗
PubMed1990

Substrate specificity for myelin basic protein-specific protein methylase I.

The substrate specificity of bovine brain myelin basic protein (MBP)-specific protein methylase I (S-adenosyl-L-methionine:protein-L-arginine N-methyltransferase, EC 2.1.1.23), which methylates arginine residues of protein, has been studied using various MBPs, several synthetic peptides and heterogeneous nuclear ribonucleoprotein complex protein (hnRNP). (1) Among MBPs from different species of brain, the carp MBP was found to be the best substrate for MBP-specific protein methylase I. This high degree of methyl acceptability is most likely due to the fact that carp MBP is not in vivo methylated at the arginine residue (Deibler, G.E. and Martenson, R.E. (1973) J. Biol. Chem. 248, 2387-2391) and that the methylatable amino acid sequence is present in this protein. (2) In order to study the minimum chain length of MBP polypeptide which functions as the methyl acceptor, several synthetic polypeptides whose sequences are identical to the region surrounding the residue 107 of bovine MBP (the in vivo methylation site) were synthesized. It was found that the hexapeptide, Gly-Lys-Gly-Arg-Gly-Leu (corresponding to residues 104-109 of bovine MBP), was the shortest methyl accepting peptide, while the tetrapeptide, Gly-Arg-Gly-Leu (corresponding to residues 106-109) was inactive as a substrate. (3) hnRNP protein is known to contain methylarginine at residue 193 (Williams, K.R., Stone, K.L., LoPresti, M.B., Merrill, B.M. and Plank, S.R. (1985) Proc. Natl. Acad. Sci. USA 82, 5666-5670) which is post-translationally modified. Thus, the RNP protein overproduced in Escherichia coli and therefore did not contain methylarginine was examined for its methyl acceptability. It was found that neither MBP-specific nor histone-specific protein methylase I could methylate this methylarginine-less RNP protein. This suggests a possible existence of a distinct protein methylase I specific for this nuclear protein.

Amino Acid Sequence↗
PubMed1990

Participation of both intracellular free Ca2+ and protein kinase C in tonic vasoconstriction induced by prostaglandin F2 alpha.

The roles of intracellular free Ca2+ and protein kinase C in the tonic contraction induced by prostaglandin were studied. Prostaglandin F2 alpha induced tonic contraction of rat thoracic aorta in both control and Ca2(+)-free solution. Close correlations were observed between the contractile response of aortic strips and the changes in intracellular free Ca2+ concentration in vascular smooth muscle cells assessed with the fluorescent Ca2+ indicator fura 2, both in control and Ca2(+)-free solutions. Prostaglandin F2 alpha also enhanced the production of inositol 1,4,5-trisphosphate in vascular smooth muscle cells before the rise of the intracellular free Ca2+ concentration. Moreover, 1-(5-isoquinoline-sulfonyl)-2-methylpiperazine, an inhibitor of protein kinase C, inhibited the tonic contractions induced by PGF2 alpha and 12-O-tetradecanoyl phorbol-13-acetate, a direct activator of protein kinase C, at similar concentrations. These results suggest that both intracellular free Ca2+ and protein kinase C participate in prostaglandin F2 alpha-induced tonic contraction.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗