Biomedical subjects

C M Kim

Publications and source records attributed to C M Kim.

At least 55 records · Page 3Linked to original sources

PubMed1997

Cardiac tamponade during transesophageal echocardiography in the patient of circumferential aortic dissection.

A 43-year-old woman, whose physical findings were consistent with Marfan's syndrome, presented with acute chest pain. Transthoracic two-dimensional echocardiography demonstrated dilated ascending aorta with a circular shape intimal flap at the root level. Subsequently, the patient required transesophageal echocardiography (TEE), but during esophageal intubation, the patient developed acute pericardial tamponade which resulted in death in spite of cardiopulmonary resuscitation. Although, some investigators recommend TEE as the first choice of diagnostic method of aortic dissection, hemodynamic stability is very important during TEE study. Therefore, aggressive sedation may be required in the case of circumferential dissection of the ascending aorta to prevent the increases of the blood pressure and the heart rate which suggested an extensive tear of the aortic intima during TEE procedure.

Adult↗

PubMed1996

Signaling mechanism of PMA-induced differentiation of K562 cells.

We have studied the signaling pathways responsible for the monocytic and/or megakaryocytic differentiation of K562 cells. The results demonstrated that although the mitogen-activated protein kinase (MAPK) was activated during the phorbol myristate acetate (PMA)-induced monocytic and/or megakaryocytic differentiation of K562 cells, the overexpression of Ha-ras which can activate the MAPK did not induce the monocytic and/or megakaryocytic differentiation of K562 cells. Instead PMA-induced megakaryocytic differentiation of K562 cells was inhibited by the pretreatment of pyrrolidine dithiocarbamate, a specific nuclear factor kappaB (NF-kappaB) inhibitor. Taken together, these results suggest that the activation of NF-kappaB rather than that of MAPK might be involved in the PMA-induced megakaryocytic differentiation of K562 cells.

Cell Differentiation↗

PubMed1996

High affinity binding of beta-adrenergic receptor kinase to microsomal membranes. Modulation of the activity of bound kinase by heterotrimeric G protein activation.

The beta-adrenergic receptor kinase (beta ARK) modulates beta-adrenergic and other G protein-coupled receptors by rapidly phosphorylating agonist-occupied receptors at the plasma membrane. We have recently shown that beta ARK also associates with intracellular microsomal membranes both "in vitro" and "in situ" (García-Higuera, I., Penela, P., Murga, C., Egea, G., Bonay, P., Benovic, J. L., and Mayor, F., Jr. (1994) J. Biol. Chem. 269, 1348-1355), thus suggesting a complex modulation of the subcellular distribution of beta ARK. In this report, we used recombinant [35S]methionine-labeled beta ARK to show that this kinase interacts rapidly with a high affinity binding site (Kd of 20 +/- 1 nM) present in salt-stripped rat liver microsomal membranes. Although beta ARK binding is not modulated by membrane preincubation with G protein activators, the activity of bound beta ARK toward rhodopsin or a synthetic peptide substrate was markedly enhanced upon stimulation of the endogenous heterotrimeric G proteins present in the microsomal membranes by AIF4- or mastoparan/guanosine 5'-(3-O-thio)triphosphate, thus strongly suggesting a functional link between these proteins and membrane-associated beta ARK. Interestingly, beta ARK association with microsomal membranes is not significantly affected by a fusion protein derived from the carboxyl terminus of beta ARK1 (the proposed location of the beta gamma subunit binding site), whereas it is markedly inhibited by fusion proteins corresponding to the amino-terminal region of the kinase. The main determinants of binding appear to be localized to an approximately 60-amino acid residue stretch (residues 88 to 145). Our results further indicate a functional relationship between beta ARK and heterotrimeric G proteins in different intracellular organelles, and suggest that additional proteins may be involved in modulating the cellular localization of the kinase through a new targeting domain of beta ARK.

Animals↗

PubMed1995

Overexpression of phospholipase C-gamma 1 in colorectal carcinomas is associated with overexpression of factors that bind its promoter.

The 5'-upstream sequence of the phospholipase C-gamma 1 (PLC-gamma 1) gene contains several transcriptional regulatory regions. We have studied one of the regions (-551 to -480, named GPE1) which exhibits a strong positive regulatory activity. GPE1 stimulated the transcription when fused to heterologous TATA element in an orientation-dependent manner. The region between -536 and -470 was identified as the protein binding site in GPE1 by the DNase I footprinting method. Electrophoretic mobility shift assays with several competitors revealed three protein binding sites in this region, designated as GES1, GES2, and GES3. The binding sites were -535 GGAGGGGGCG -524, -512 TGTCACTCA -504, and -491 CAATCCA -485, respectively. Mutational analyses suggested that GPE1 binding proteins cooperate with each other to activate the transcription of the PLC-gamma 1 gene. Additionally, immunoblot analyses revealed that the level of PLC-gamma 1 expression was considerably higher in 9 of 11 colorectal carcinomas than in adjacent normal colorectal tissues. In 7 of 9 cases of colorectal carcinomas which express higher level of PLC-gamma 1, the DNA binding activities to GES1, GES2, and GES3 sites also increased when compared with normal tissues. These results suggest that the GPE1 binding proteins might be attributed to the elevated expression of PLC-gamma 1 in colorectal carcinomas and may play important roles in proliferation of colorectal carcinoma cells.

Animals↗

PubMed1995

Phosphorylation of the N-formyl peptide receptor carboxyl terminus by the G protein-coupled receptor kinase, GRK2.

Attenuation of receptor-mediated signal amplification in response to external stimuli, an essential step in the balance of cellular activation, may be mediated by receptor phosphorylation. We have recently shown that the carboxyl-terminal cytoplasmic domain of the N-formyl peptide receptor (FPR) interacts with G proteins and demonstrate here that this same region of the FPR is specifically phosphorylated by a neutrophil cytosolic kinase with properties similar to the G protein-coupled receptor kinase, GRK2. Both kinase activities show a lack of sensitivity toward protein kinase A, protein kinase C, and tyrosine kinase inhibitors but demonstrate almost identical sensitivity toward the kinase inhibitor heparin. Kinetic studies demonstrated that GRK2 has a Km for the carboxyl-terminal domain of the FPR of approximately 1.5 microM and that denaturation of the substrate results in an almost complete loss of phosphorylation. Comparative studies reveal that GRK3 has approximately 50% of the activity of GRK2 toward the FPR carboxyl terminus, whereas GRK5 and GRK6 have no detectable activity. Site-directed mutagenesis of numerous regions of the FPR carboxyl terminus demonstrated that, whereas Glu326/Asp327 and Asp333 are critical for phosphorylation, the carboxyl-terminal 10 amino acids are not required. Simultaneous substitution of Thr334, Thr336, Ser338, and Thr339 resulted in an approximately 50% reduction in phosphorylation, whereas simultaneous substitution of the upstream Ser328, Thr329, Thr331, and Ser332 or merely the Ser328 and Thr329 residues resulted in an approximately 80% reduction in phosphorylation. The introduction of negatively charged glutamate residues for Ser328 and Thr329 or Thr331 and Ser332 resulted in marked stimulation of phosphorylation. These results suggest a hierarchical mechanism in which phosphorylation of amino-terminal serine and threonine residues is required for the subsequent phosphorylation of carboxyl-terminal residues. These results provide the first direct evidence that an intracellular domain of a chemoattractant receptor is a high affinity substrate for GRK2 and further suggest a role for GRK2 or a closely related kinase in the attenuation of receptor-mediated activation of inflammatory cells.

Amino Acid Sequence↗

PubMed1995

Arrestin interactions with G protein-coupled receptors. Direct binding studies of wild type and mutant arrestins with rhodopsin, beta 2-adrenergic, and m2 muscarinic cholinergic receptors.

Arrestins play an important role in quenching signal transduction initiated by G protein-coupled receptors. To explore the specificity of arrestin-receptor interaction, we have characterized the ability of various wild-type arrestins to bind to rhodopsin, the beta 2-adrenergic receptor (beta 2AR), and the m2 muscarinic cholinergic receptor (m2 mAChR). Visual arrestin was found to be the most selective arrestin since it discriminated best between the three different receptors tested (highest binding to rhodopsin) as well as between the phosphorylation and activation state of the receptor (> 10-fold higher binding to the phosphorylated light-activated form of rhodopsin compared to any other form of rhodopsin). While beta-arrestin and arrestin 3 were also found to preferentially bind to the phosphorylated activated form of a given receptor, they only modestly discriminated among the three receptors tested. To explore the structural characteristics important in arrestin function, we constructed a series of truncated and chimeric arrestins. Analysis of the binding characteristics of the various mutant arrestins suggests a common molecular mechanism involved in determining receptor binding selectivity. Structural elements that contribute to arrestin binding include: 1) a C-terminal acidic region that serves a regulatory role in controlling arrestin binding selectivity toward the phosphorylated and activated form of a receptor, without directly participating in receptor interaction; 2) a basic N-terminal domain that directly participates in receptor interaction and appears to serve a regulatory role via intramolecular interaction with the C-terminal acidic region; and 3) two centrally localized domains that are directly involved in determining receptor binding specificity and selectivity. A comparative structure-function model of all arrestins and a kinetic model of beta-arrestin and arrestin 3 interaction with receptors are proposed.

Animals↗

PubMed1995

Infestation rate of head lice in primary school children in Inchon, Korea.

The survey of the head louse infestation of primary school children in Inchon city was carried out in May 26-27, 1995. Total number of the children surveyed were 1,530. Four (0.5%) out of 768 boys were infested with nits or adults/nymphs of lice and 72 (9.4%) out of 762 girls were positive with those of lice. The infestation rate of lice for girls was 19 times higher than that of boys.

Child↗

PubMed1994

Visual arrestin binding to rhodopsin. Intramolecular interaction between the basic N terminus and acidic C terminus of arrestin may regulate binding selectivity.

Visual arrestin plays an important role in quenching phototransduction via its ability to preferentially bind to phosphorylated light-activated rhodopsin (P-Rh*). Recently we proposed a mechanism for the binding of visual arrestin to P-Rh* that helps to explain the nature of the conformational changes in arrestin observed upon binding. This mechanism involves a multisite interaction between arrestin and P-Rh* and implies an interaction between the C-terminal and N-terminal domains of arrestin. To obtain further insight into the mechanism of arrestin-rhodopsin interaction we have characterized the ability of polyanions to inhibit the interaction of wild type and mutant arrestins to different functional forms of rhodopsin. These studies reveal that: 1) heparin is most potent at inhibiting arrestin binding to dark phosphorylated rhodopsin > light-activated rhodopsin > P-Rh*; 2) C-terminal deletions in arrestin increase arrestin sensitivity to heparin inhibition while an N-terminal deletion (residues 2-16) decreases heparin inhibition; 3) the sensitivity of chimeric arrestins to heparin inhibition is determined by the origin of the N terminus of the chimera; and 4) heparin also inhibits arrestin binding to truncated 329G-Rh*, suggesting it does not mimic the phosphorylated C terminus of rhodopsin. Taken together, these data suggest that heparin mimics the regulatory acidic C terminus of arrestin. Since the basic N-terminal region of arrestin appears to serve as a site of heparin binding it is a likely candidate to be involved in the intramolecular interaction with the C-terminal region. The interaction of the N- and C-terminal domains of arrestin may control the conformational rearrangements in arrestin that occur upon binding to P-Rh*.

Animals↗

PubMed1993

Binding of wild type and chimeric arrestins to the m2 muscarinic cholinergic receptor.

Arrestins play an important role in regulating the activity of the G protein-coupled receptors rhodopsin and the beta 2-adrenergic receptor. Recently, we described the expression and functional characterization of visual arrestin using an in vitro translation system. Here we report the expression of beta-arrestin and development of a direct binding assay to study the interaction of arrestins with a muscarinic cholinergic receptor. In vitro translated beta-arrestin was found to specifically bind to purified reconstituted human m2 muscarinic cholinergic receptor (hm2 mAChR) in an agonist- and phosphorylation-dependent manner. Visual arrestin also bound to the hm2 mAChR, albeit to a lesser extent and with lower affinity. In an attempt to dissect the major domains responsible for determining the receptor binding specificity of arrestin and beta-arrestin, we generated several chimeric arrestins. One contained the first 340 residues of beta-arrestin followed by residues 346-404 of arrestin (BRV4), another consisted of the first 207 residues of beta-arrestin and residues 214-404 of visual arrestin (BV3), and a third had residues 1-43 of beta-arrestin replaced by residues 1-47 of arrestin (VIN1). All of these arrestins were able to specifically bind to the activated and phosphorylated form of both the hm2 mAChR and rhodopsin, with a clear preference for the muscarinic receptor. The Kd values for beta-arrestin, BRV4, BV3, VIN1, and visual arrestin binding to the hm2 mAChR were 0.48 +/- 0.06, 0.51 +/- 0.19, 1.38 +/- 0.26, 1.13 +/- 0.26, and 7.2 +/- 1.2 nM, respectively. These data demonstrate that: 1) beta-arrestin binds to the hm2 mAChR in an activation- and phosphorylation-dependent fashion, 2) visual arrestin has 15-fold lower affinity for the hm2 mAChR as compared to beta-arrestin, and 3) the N-terminal half of beta-arrestin plays a key role in determining receptor binding specificity. The use of in vitro translated arrestins to directly assess receptor binding may serve as a viable approach for elucidating the specificity and molecular mechanisms involved in receptor-arrestin interaction.

Animals↗

PubMed1993

Mechanism of beta-adrenergic receptor kinase activation by G proteins.

The beta-adrenergic receptor kinase (beta-ARK) specifically phosphorylates the activated form of various G protein-coupled receptors such as the beta 2-adrenergic receptor (beta 2-AR). Recently, G protein beta gamma subunits have been demonstrated to activate beta-ARK-mediated receptor phosphorylation. To further elucidate beta-ARK/G protein interactions, we have developed a direct binding assay. The direct binding of [35S]methionine-labeled beta-ARK to either brain Gi/Go or beta gamma subunits was rapid and saturable with similar Kd values of approximately 58 and approximately 32 nM, respectively. Both heterotrimeric G proteins and beta gamma subunits enhanced the initial rate of beta 2-AR and rhodopsin phosphorylation approximately 10-fold. Kinetic studies demonstrate that beta gamma enhances beta-ARK-mediated beta 2-AR phosphorylation both by decreasing the Km for the beta 2-AR approximately 4-fold and increasing the stoichiometry of phosphorylation from approximately 4 to approximately 11 mol/mol. An agonist- and ATP-dependent binding of beta-ARK to the reconstituted beta 2-AR was also demonstrated. In addition, beta-ARK binding was enhanced in the presence of both the activated beta 2-AR and beta gamma subunits suggesting the formation of a transient ternary complex consisting of beta-ARK, beta gamma, and beta 2-AR. Overall, these studies suggest that the specific association of beta-ARK with heterotrimeric G proteins may play an important role in promoting receptor/kinase interaction and subsequent receptor phosphorylation.

Amino Acid Sequence↗

PubMed1993

The substance P receptor, which couples to Gq/11, is a substrate of beta-adrenergic receptor kinase 1 and 2.

The agonist-occupied forms of several G-protein-coupled receptors that modulate the activity of adenylycyclase via Gs (e.g. beta 2-adrenergic) or Gi (e.g. alpha 2-adrenergic and cardiac muscarinic) are phosphorylated by beta-adrenergic receptor kinases (beta ARK 1 and beta ARK 2). beta ARK-catalyzed phosphorylation of these receptors appears to correlate with their agonist-induced desensitization. The possibility that beta ARK isozymes may also be involved in the desensitization of other G-protein-coupled receptors such as those mediating phosphoinositide (PI) hydrolysis was tested by determining the phosphorylation of the substance P receptor (SPR), which is coupled to PI hydrolysis in numerous tissues. Rat SPR was expressed in Sf9 cells, partially purified, and reconstituted in phospholipid vesicles. The reconstituted SPR bound the SPR agonist substance P, 125I-labeled with Bolton-Hunter reagent, with low affinity. However, addition of purified Gq/11 to the reconstituted SPR resulted in the conversion of all the receptors to a high affinity state, suggesting that SPR couples to Gq/11. Phosphorylation of the reconstituted SPR with purified beta ARK 1 or 2 in the absence and presence of substance P (SP) was then studied. In the presence of 100 microM SP, both kinases promoted phosphorylation of the receptor to a stoichiometry of 9 +/- 2 mol of phosphate/mol of receptor. However, no phosphorylation of the receptor could be detected in the absence of agonist. Agonist-induced phosphorylation of the receptor was blocked by coincubation with the SPR antagonist spantide. These results show that beta ARK isozymes may regulate the function of both adenylylcyclase as well as PI-coupled receptors, and suggest a role for beta ARK isozymes in SPR signal transduction.

Animals↗

PubMed1993

Beta-adrenergic receptor kinase. Agonist-dependent receptor binding promotes kinase activation.

The beta-adrenergic receptor kinase (beta ARK) specifically phosphorylates the activated form of multiple receptors such as the beta 2-adrenergic receptor (beta 2 AR) and rhodopsin. beta ARK also phosphorylates synthetic peptides, albeit with an approximately 10(4)-10(7)-fold lower Vmax/Km ratio as compared to receptors, with a clear preference for peptides containing acidic residues on the aminoterminal side of a serine or threonine. To further characterize the mechanism of substrate phosphorylation by beta ARK, we designed a series of analogue peptides containing a single amino acid change (serine, glutamic acid, or phosphoserine) situated 2 or 4 residues amino-terminal to the target serine. While beta ARK weakly phosphorylated peptides lacking an acidic residue, peptides containing either a single phosphoserine or glutamic acid were substantially better substrates with a 3.5- to 8-fold increase in Vmax. Additional studies demonstrated that the interaction of beta ARK with an activated receptor (beta 2AR* or Rho*) also significantly enhanced peptide phosphorylation. Both Rho* and a truncated rhodopsin lacking its carboxyl-terminal phosphorylation sites activated peptide phosphorylation to a similar extent with EC50 values for activation of 0.65 and 1.34 microM, respectively. In contrast, the agonist-occupied beta 2AR activated peptide phosphorylation by beta ARK with a substantially higher affinity (EC50 of 0.012 microM) compared to Rho*. The Vmax/Km ratio for beta ARK phosphorylation of a poor peptide substrate such as RRRASAAASAA was increased up to approximately 200-fold by the activated receptor while the phosphorylation of a good peptide substrate (RRREEEEESAAA) was increased only up to approximately 8-fold. Our results suggest that acidic residues (glutamic acid or phosphoserine) localized on the amino-terminal side of target serines are important but not essential determinants in directing peptide phosphorylation. The substrate specificity of beta ARK appears to rely more strongly on the overall topological structure of the activated receptor which promotes the specific binding and activation of beta ARK.

Adrenergic beta-Agonists↗

PubMed1993

Loss of retinoblastoma gene and amplification of N-myc gene in retinoblastoma.

We have analyzed paired samples of genomic DNA from peripheral leukocyte and primary tumor tissue from nine patients with retinoblastoma (RB) and from two RB cell lines, WERI-Rb-1 and Y79, to detect the molecular alterations of the retinoblastoma susceptibility gene (RB-1) and N-myc gene. In Southern analysis, RB-1 deletions in tumor tissues were detected in five patients (56%), one of these revealed a total loss of RB-1. N-myc amplification was found only in one (11.1%) out of nine patients. We also observed a total loss of RB-1 in WERI-Rb-1, and a more than 100-fold amplification of N-myc in Y79. The analysis of the relationship between molecular events and clinical characteristics such as age, sex, tumor laterality did not reveal any specific correlation. These results suggest that genetic backgrounds of RB in Korean patients are quite similar to those of reported cases elsewhere. The high sensitivity of our method in detecting the RB-1 loss indicates that this method can be a useful tool for initially screening a large number of tumors.

Child↗

PubMed1993

Chemosensitization to adriamycin by cyclosporin A and verapamil in human retinoblastoma cell lines.

The chemosensitizing effects of cyclosporin A and verapamil on the cytotoxicity of adriamycin were investigated using MTT assay against two human retinoblastoma cell lines, Y79 and WERI-Rb-1. Y79 and WERI-Rb-1 were totally resistant to doses up to 5.0 micrograms/ml of verapamil. Cyclosporin A inhibited the survival of Y79 and WERI-Rb-1 dose-dependently, however, the maximum inhibition at the highest concentration tested (5.0 micrograms/ml) was less than 50% (% survival at 5.0 micrograms/ml of cyclosporin A: 65.6% and 66.9% in Y79 and WERI-Rb-1, respectively). Combination of cyclosporin A and verapamil did not further inhibit the survival of Y79 and WERI-Rb-1 compared with cyclosporin A alone. Adramycin inhibited the survival of Y79 and WERI-Rb-1 dose-dependently. The chemosensitizing effects of cyclosporin A and verapamil on the cytotoxicity of adriamycin were evaluated in terms of sensitizing index (SI: the ratio of IC50 to adriamycin alone to IC50 to adriamycin in the presence of cyclosporin A and/or verapamil). Cyclosporin A significantly enhanced SI and the addition of verapamil enhanced SI further: SI values at 5.0 micrograms/ml of cyclosporin A, 5.0 micrograms/ml of cyclosporin A plus 1.5 micrograms/ml of cyclosporin A plus 1.5 micrograms/ml of verapamil, 5.0 micrograms/ml of cyclosporin A plus 3.0 micrograms/ml of verapamil were 2.0, 2.6 and 2.8 in Y79 and 2.6, 5.8 and 9.7 in WERI-Rb-1, respectively. These results suggest that cyclosporin A and verapamil are promising chemosensitizers to adriamycin in the treatment of retinoblastoma.

Cell Survival↗

PubMed1993

Expression and characterization of two beta-adrenergic receptor kinase isoforms using the baculovirus expression system.

The beta-adrenergic receptor kinases, beta ARK1 and beta ARK2, are two recently cloned members of the G protein-coupled receptor kinase family. To further characterize these kinases, bovine beta ARK1 and beta ARK2 have been overexpressed in Sf9 insect cells using the baculovirus expression system. High yields (5-7 mg/L cells) of purified kinase preparations were obtained by sequential chromatography of infected Sf9 cell supernatant fractions on S-Sepharose and Heparin-Sepharose. The expressed kinases were fully active as evidenced by their ability to specifically phosphorylate the agonist-occupied beta 2-adrenergic receptor (beta 2AR) and light-activated rhodopsin. Similar initial rates and maximal stoichiometries of beta 2AR phosphorylation were observed for both beta ARK1 and beta ARK2. Moreover, G protein beta gamma subunits enhanced the initial rates of both beta ARK1 and beta ARK2 mediated beta 2AR phosphorylation by approximately tenfold. In the presence of beta gamma subunits the maximal stoichiometry of beta 2AR phosphorylation was increased from approximately 4 mol phosphate/mol receptor to approximately 10 mol/mol. Detailed kinetic analysis of rhodopsin phosphorylation suggests that both kinases follow a sequential mechanistic pathway and have similar Kms for rhodopsin (approximately 14 microM) and MgATP (60-90 microM). Peptide phosphorylation studies demonstrate that both kinases prefer acidic amino acids amino terminal to a serine. Heparin was found to be the most potent inhibitor for both kinases with IC50s of 1.4 and 1.1 microM for beta ARK1 and beta ARK2, respectively. These studies demonstrate that beta ARK1 and beta ARK2 share very similar kinetic properties and suggest that they may have a similar substrate specificity in vivo.

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

PubMed1992

cDNA cloning of MEV, a mutant protein that facilitates cellular uptake of mevalonate, and identification of the point mutation responsible for its gain of function.

We report the expression cloning of pMev, a cDNA that facilitates cellular uptake of mevalonate. pMev was isolated from the met-18b-2 clone of Chinese hamster ovary (CHO) cells, which were selected for growth in low concentrations of mevalonate when synthesis is blocked by compactin (Faust, J. R., and Krieger, M. (1987) J. Biol. Chem. 262, 1996-2004). pMev encodes a 494-residue protein, Mev, that is predicted to have 12 membrane-spanning regions, consistent with a membrane transporter. Surprisingly, levels of Mev mRNA and protein are similar in CHO and met-18b-2 cells. The Mev gene differs from the wild-type gene by a single base change that substitutes a cysteine for phenylalanine in the 10th membrane-spanning region. met-18b-2 cells are heterozygous for this dominant gain-of-function mutation. Transfection of a cDNA encoding pMev, but not the wild-type cDNA, elicited a marked increase in [3H]mevalonate uptake and incorporation into cellular lipids in stably and transiently transfected cells. The availability of pMev will facilitate studies of [3H]mevalonate incorporation into trace products, including p21ras and other prenylated proteins.

Amino Acid Sequence↗

PubMed1992

Modification of adriamycin-induced cytotoxicity by recombinant human interferon-gamma and/or verapamil in human stomach cancer cells.

Recombinant human-interferon-gamma (rH-IFN-gamma) and verapamil (VRP), either alone or in combination, were evaluated in MTT assay for their modification effects on adriamycin-induced cytotoxicity against MKN-45, human stomach adenocarcinoma cells. VRP as a single agent did not inhibit the survival of MKN-45 at doses of up to 5.0 micrograms/ml. The survival of MKN-45 was inhibited by rH-IFN-gamma dose-dependently and further inhibited by the addition of VRP. However, the maximum growth inhibition of MKN-45 in any combination treatment with rH-IFN-gamma and VRP was less than 50% except in the highest concentration combinations (% survival: 47.9% at 10(4) U/ml of rH-IFN-gamma and 3.0 micrograms/ml of VRP). Adriamycin caused a concentration-dependent cytotoxicity and its cytotoxicity was significantly enhanced by the addition of rH-IFN-gamma and further enhanced by the combined use of rH-IFN-gamma and VRP. The modification effects of rH-IFN-gamma and VRP on adriamycin-induced cytotoxicity were evaluated in terms of modification index (MI), demonstrating that rH-IFN-gamma significantly increased in adriamycin-induced cytotoxicity and that the combined use of rH-IFN-gamma and VRP enhanced the adriamycin-induced cytotoxicity to a greater extent than did rH-IFN-gamma alone: MI values at 10(2) U/ml and 10(3) U/ml of rH-IFN-gamma were 1.7 and 3.1, respectively; those at 1.5 micrograms/ml and 3.0 micrograms/ml of VRP in the presence of 10(3) U/ml of rH-IFN-gamma were 4.4 and 6.0, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗

PubMed1992

Malignant lymphomas of the nasal cavity and Waldeyer's ring--clinicopathologic and immunohistochemical study.

The clinicopathologic and immunohistochemical finding of 10 cases of nasal non-Hodgkin's lymphoma (NHL) and 23 cases of Waldeyer's ring NHL were studied. Immunohistochemically, nasal NHL expressed T-cell markers exclusively, whereas the NHL of Waldeyer's ring were of both T-cell (56.5%) and B-cell lineages (43.5%). Angioinvasiveness by tumor cells was exclusively noted in the T-lineage lymphomas. Epithelial hyperplasia, epitheliotropism by tumor cells, and extensive invasion of adjacent normal tissue were more prominent in T-cell lymphomas than in B-cell lymphomas. T-lineage lymphomas showed distant extranodal spread pattern involving the skin, soft tissue, stomach, spleen, and the liver, whereas B-lineage lymphomas tended to localize in the lymph nodes. The survival rate of Nasal NHL was similar to that of Waldeyer's ring NHL. Although not statistically significant because of small sample numbers, immunophenotype, histologic groups of monomorphic lymphoma, and stage had prognostic importance. In general, T-lineage lymphomas presented with a higher stage than B-lineage lymphomas (p < 0.05)-and overall survival was poor. Stage I disease showed a much more favorable prognosis than stage II disease. Monomorphic lymphomas had a shorter survival than polymorphic reticulosis (PR) or lymphomas with features of PR. This result in conjunction with the morphologic transition between them suggested that monomorphic lymphoma may represent the most advanced stage in the spectrum of PR, lymphoma with features of PR, and monomorphic lymphoma.

Adolescent↗