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Biomedical subjects

B Kim

Publications and source records attributed to B Kim.

At least 163 records · Page 9Linked to original sources
PubMed1992

Analogues of diadenosine 5',5'''-P1,P4-tetraphosphate (Ap4A) as potential anti-platelet-aggregation agents.

Dense granules of platelets contain a high content of diadenosine 5',5'''-P1,P4-tetraphosphate (Ap4A). We have previously demonstrated an antithrombotic effect of this compound in a live rabbit model. In the present study we find that certain synthetic Ap4A analogues are superior to Ap4A in inhibiting ADP-induced aggregation of human platelets. Analogues having a P--C--P bridge located in the P2,P3 position of Ap4A are the most potent inhibitors. These analogues are also resistant to hydrolytic enzymes. Analogues having the above characteristics exhibit competitive inhibition with ADP in the ADP-induced platelet aggregation reaction. These compounds, such as AppCHFppA, may be useful as antithrombotic agents. The analogues ApSppSpA and ApSpCHFpSpA also showed good inhibitory effects on ADP-induced platelet aggregation. In addition, this action of Ap4A and its analogues provides an example of a dinucleotide inducing an antagonistic effect by occupying an extracellular mononucleotide binding site on platelets. It calls attention to the possibility that Ap4A and its analogues may act in a similar way in whole organisms, triggering effector or inhibitory responses in any one of a variety of cells.

Adenosine Diphosphate↗
PubMed1992

Dimerization of a specific DNA-binding protein on the DNA.

Many specific DNA-binding proteins bind to sites with dyad symmetry, and the bound form of the protein is a dimer. For some proteins, dimers form in solution and bind to DNA. LexA repressor of Escherichia coli has been used to test an alternative binding model in which two monomers bind sequentially. This model predicts that a repressor monomer should bind with high specificity to an isolated operator half-site. Monomer binding to a half-site was observed. A second monomer bound to an intact operator far more tightly than the first monomer; this cooperativity arose from protein-protein contacts.

Bacterial Proteins↗
PubMed1992

Surgical resection following interleukin 2 therapy for metastatic renal cell carcinoma prolongs remission.

Records of 399 patients with metastatic renal cell carcinoma treated with interleukin 2 with or without lymphokine-activated killer cell immunotherapy enrolled in 14 separate clinical trials from multiple institutions were reviewed to determine whether patients with a partial response to interleukin 2 therapy would benefit from surgical resection of residual tumor. Sixty-two patients demonstrated objective responses (15.5%), 18 (4.5%) complete and 44 (11.0%) partial. Eleven patients underwent resection of residual tumor in the lung, kidney, retroperitoneum, or pelvis so that they had "surgically no evidence of disease" (SNED). Of these, 10 had partial responses, and one patient with progressive disease had a complete response. Comparison of response duration showed no difference between the complete response and SNED groups, but there was a significant difference between each of these groups and the partial response group. At this writing, all 11 patients in the SNED group remained alive without evidence of disease (median follow-up, 21 months). In contrast, only 14 patients (76%) with complete responses and 15 patients (35%) with partial responses remained free of disease progression. Enhanced survival of the complete response and SNED groups compared with the partial response group borders on significance and awaits longer follow-up. These data suggest that surgical resection, if technically feasible, may benefit patients who show a partial response to interleukin 2 treatment for metastatic renal cell carcinoma.

Adolescent↗
PubMed1992

Lectin-based homogeneous enzyme-linked binding assay for estimating the type and relative amount of carbohydrate within intact glycoproteins.

The feasibility of using a new lectin-based homogeneous enzyme-linked binding assay for estimating the type and relative amount of specific carbohydrate structures within intact glycoproteins is examined. Malate dehydrogenase-galactose, -mannose, and -N-acetylglucosamine conjugates are utilized in conjunction with Jacalin, concanavalin A, and wheat germ agglutinin, respectively. The catalytic activity of the glyco-enzyme conjugates is inhibited significantly (greater than 60%) in solution in the presence of the respective lectins. The observed inhibition for each reagent set is reversed in proportion to the type and relative amount of specific carbohydrates present within test glycoproteins added to the assay mixture. Competitive binding ED50 values for a number of synthetic and native model glycoproteins correlate well with the known carbohydrate content of these species. The proposed method is much faster than previous solid-phase lectin-based enzyme-linked methods used to probe carbohydrate content/structure (less than 15 min) and has the potential to be fully automated.

Acetylglucosamine↗
PubMed1991

Enhanced survival of IFN-alpha augmented IL-2 therapy of pulmonary metastases: efficacy comparable to interleukin-2 and lymphokine activated killer cells.

Recently, we reported enhanced tumor reduction using recombinant interferon-alpha A/D (IFN) combined with interleukin-2 (IL-2). Similar synergism affecting survival was assessed in treatment of both early and advanced pulmonary metastases. This combination was compared with the current "standard" IL-2 and lymphokine activated killer (LAK) therapy in the treatment of early and advanced pulmonary metastases. C57BL/6 mice injected via tail vein with the weakly immunogenic methylcholanthrene-induced murine fibrosarcoma MCA-106 were treated intraperitoneally with IL-2 (50,000 units b.i.d.), IFN (50,000 units q.d.), LAK (2.5-10 x 10(7)), or various combinations of above. Treatment of both early Day 3 and advanced Day 10 metastases using IL-2/IFN reduced metastases and prolonged survival over both controls and IL-2 alone. It was superior to IFN, LAK, and IFN/LAK. Addition of LAK to IL-2/IFN demonstrated no added benefit. Although no mortality was observed during treatment of Day 3 metastases, treatment of Day 10 advanced pulmonary metastases for 9 days with IL-2/IFN resulted in early deaths (33%) without visible tumor, indicating possible toxicity of treatment. These results show survival benefit of IL-2/IFN over IL-2, IFN, or LAK treatment in the therapy of early and advanced pulmonary metastases, albeit with added toxicity. Its relative simplicity and comparable efficacy to the more complex and costly IL-2/LAK provide important advantages for potential clinical applications.

Animals↗
PubMed1991

Anti-CD3-enhanced interleukin-2 immunotherapy of pulmonary metastases.

UNLABELLED: A newly developed monoclonal rat IgG 2b antibody which in vitro can activate both helper and cytolytic T-lymphocytes by binding to the CD3 epsilon subunit of the T-cell receptor complex was tested alone and in combination with Interleukin-2, a growth factor for activated T-cells, for ability to reduce established pulmonary metastases in a murine model. C57BL/6 mice injected iv with a tumor cell suspension of a weakly immunogenic fibrosarcoma, MCA106, were randomly assigned to 1 of 15 treatment groups for intraperitoneal injections with YCD3 (0, 0.1, 1, 10, or 100 micrograms) on Days 3, 5, 7, 10, 12, 17, and 19 or with IL-2 (0, 1000, or 50,000 units bid) on Days 3 through 7, 10 through 12, and 17 through 19. On Day 21 all mice were sacrificed for enumeration of metastases. Pooled splenocytes of three randomly selected mice from each group were assayed for surface expressions of T-cell markers Thy-1, Ly2, and L3T4. RESULTS: High-dose IL-2 (50,000 units bid) in combination with low-dose YCD3 (1 microgram) reduced metastases 60% (P less than 0.005). YCD3 or IL-2 alone was ineffective. Combined high-dose IL-2 (50,000 units) and high-dose YCD3 (100 micrograms) resulted in 100% mortality. Phenotypically, YCD3 induced a dose-dependent depletion of T-cells from 25 to 2.4% (0.1 to 100 micrograms, respectively). These results suggest potential clinical applicability of low-dose anti-CD3 monoclonal antibody to enhance antitumor efficacy of high-dose IL-2. However, the toxicity of high-dose anti-CD3 and high-dose IL-2 cautions for care in selection of dose.

Animals↗
PubMed1991

Interleukin-2 immunotherapy followed by resection of residual renal cell carcinoma.

We administered 10 (E5) units per kg. interleukin-2, 3 times daily, with or without lymphokine-activated killer cells, to 10 patients with metastatic renal cell carcinoma. All patients had metastases to the lung, and 3 of 5 patients who had previously undergone nephrectomy had metastases to the renal fossa. Of the 9 patients who completed at least 1 course of therapy 3 had complete regression of disease outside the abdomen, including 2 who were rendered disease-free after subsequent cytoreductive surgery (nephrectomy in 1 and resection of the renal fossa recurrence in 1). Viable tumor comprised less than 1% of each surgical specimen. Our results support the view that initial treatment with interleukin-2 immunotherapy, followed by abdominal cytoreductive surgery if the peripheral metastases have regressed, may be preferable to the practice of performing abdominal cytoreductive surgery before administering interleukin-2 immunotherapy for patients with widely metastatic renal cell carcinoma.

Adult↗
PubMed1991

The clearance and degradation of oligodeoxynucleotides following intravenous injection into rabbits.

A 32P-labeled oligodeoxynucleotide of 20 bases was found to be quite stable in freshly drawn rabbit or human blood and no degradation was apparent within 2 hr. In contrast, following injection into rabbits, the same oligodeoxynucleotide was cleared from the blood rapidly and at least 17% was completely degraded within 5 min. After 90 min, 16% of the oligonucleotide was found largely intact in the urine. At this time, radioisotope was also found in all the solid tissues tested but probably not as intact oligonucleotide.

Animals↗
PubMed1990

Homogeneous enzyme-linked binding assay for studying the interaction of lectins with carbohydrates and glycoproteins.

A simple and rapid homogeneous enzyme-linked binding assay method for studying lectin-carbohydrate interactions is described. The method is based on the homogeneous inhibition of appropriate enzyme-saccharide conjugates by specific carbohydrate-binding lectins. In the presence of carbohydrate structures recognized by the lectins, enzyme activity is regained in an amount of proportional to the concentration of carbohydrate. The new method can be used to rapidly assess the relative carbohydrate specificity of the various lectins and for the selective analytical detection of simple saccharides and complex glycoproteins. Indeed, when Jacalin lectin is used in conjunction with a malate dehydrogenase-galactose conjugate, selective measurement of human IgA (immunoglobulin A) at microgram per milliliter levels in less than 10 min is possible. The potential for using this analytical methodology for determining changes in the carbohydrate structure of intact recombinant glycoproteins is also discussed.

Carbohydrates↗
PubMed1990

Evaluation of estimations in vitro of tissue/blood distribution coefficients for organothiophosphate insecticides.

Physiologically based pharmacokinetic (PBPK) modeling of foreign chemicals is dependent on the accurate determination of their tissue/blood distribution coefficients, Kp (partition coefficients). The present study was undertaken to evaluate the validity of the in vitro estimation of the Kp values of the organothiophosphate insecticides parathion and methyl parathion by equilibrium dialysis. Data derived from previously published studies that utilized single-pass perfusions of mouse livers in situ with parathion or methyl parathion were analyzed to determine liver/perfusate Kp values from the equation Kp = (t 1/2ss) (Q)/(0.693) (VH), where Kp is the liver/perfusate distribution ratio, t 1/2ss is the half-life for approach to steady state of the chemical, VH is the liver volume, and Q is the perfusate flow rate. Kp values for methyl parathion were calculated to be 16.4 +/- 7.5 and 9.5 +/- 2.7 (mean +/- SD) for perfused livers and equilibrium dialysis, respectively, while estimates of Kp for parathion were 15.6 +/- 6.3 and 19.5 +/- 5.5 for perfused livers and equilibrium dialysis, respectively. These results indicate that equilibrium dialysis can be utilized to give an accurate estimate of tissue partitioning of parathion and methyl parathion from perfusate into perfused mouse livers.

Animals↗
PubMed1990

High-resolution structure of an HIV zinc fingerlike domain via a new NMR-based distance geometry approach.

A new method is described for determining molecular structures from NMR data. The approach utilizes 2D NOESY back-calculations to generate simulated spectra for structures obtained from distance geometry (DG) computations. Comparison of experimental and back-calculated spectra, including analysis of cross-peak buildup and auto-peak decay with increasing mixing time, provides a quantitative measure of the consistence between the experimental data and generated structures and allows for use of tighter interproton distance constraints. For the first time, the "goodness" of the generated structures is evaluated on the basis of their consistence with the actual experimental data rather than on the basis of consistence with other generated structures. This method is applied to the structure determination of an 18-residue peptide with an amino acid sequence comprising the first zinc fingerlike domain from the gag protein p55 of HIV. This is the first structure determination to atomic resolution for a retroviral zinc fingerlike complex. The peptide [Zn(p55F1)] exhibits a novel folding pattern that includes type I and type II NH-S tight turns and is stabilized both by coordination of the three Cys and one His residues to zinc and by extensive internal hydrogen bonding. The backbone folding is significantly different from that of a "classical" DNA-binding zinc finger. Residues C(1)-F(2)-N(3)-C(4)-G(5)-K(6) fold in a manner virtually identical with the folding observed by X-ray crystallography for related residues in the iron domain of rubredoxin; superposition of all main-chain and Cys side-chain atoms of residues C(1)-K(6) of Zn(p55F1) onto residues C(6)-Y(11) and C(39)-V(44) of rubredoxin gives RMSDs of 0.46 and 0.35 A, respectively. The side chains of conservatively substituted Phe and Ile residues implicated in genomic RNA recognition form a hydrophobic patch on the peptide surface.

Amino Acid Sequence↗
PubMed1990

Human blood cells at microgravity: the NASA Initial Blood Storage Experiment.

The Initial Blood Storage Experiment (IBSE) probed the behavior of human red cells, white cells, and platelets during exposure to microgravity for 6 days and 2 hours on a National Aeronautics and Space Administration (NASA) shuttle mission, named STS 61-C, which was launched on January 12, 1986. IBSE involved carefully controlled comparisons between two identical sets of blood cells, one exposed to microgravity and the other held on the ground. Specially designed and fabricated, electrically powered environmental chambers provided appropriate environmental temperatures and air flow to support cell metabolism throughout the experiment. To circumvent the need for constant agitation of platelets during storage, a new thin-layer compression method for platelet preservation was developed. Blood cell samples were allocated to the two arms of the experiment, microgravity and earth gravity, by blind assignment. Moreover, to ensure unbiased assessment of the experiment's findings, postexperiment samples for measurement were identified by code. To optimize the chances of detecting possible gravitational effects, a wide array of measurements of cellular function, morphology, metabolism, and immunology were made. Analysis of variance was used in analyzing the data. The most striking finding was that platelets displayed markedly superior structural and functional integrity at microgravity. Granulocytes held on the ground were preserved slightly better than those that orbited in the shuttle, whereas red cells displayed few effects that were attributable to the gravitational variable. Polyvinylchloride-di-(2-ethylhexyl)phthalate (PVC-DEHP) was the plastic of choice for storage of red cells, while PVC-trioctyltrimellitate (TOTM) was superior to PVC-DEHP and polyolefin (PO) for platelets.

Aerospace Medicine↗
PubMed1990

Acalculus lymphoeosinophilic cholecystitis associated with interleukin-2 and lymphokine-activated killer cell therapy.

A case of unusual cholecystitis that developed on completion of interleukin-2 and lymphokine-activated killer cell therapy is described. A 62-year-old man was treated with interleukin-2 and lymphokine-activated killer cells for disseminated renal cell carcinoma. During the course of the immunotherapy, his serum alkaline phosphatase level increased, as did the peripheral eosinophil count (0.31). Subsequently, clinical and radiologic evidence of acute cholecystitis was noted. The removed gallbladder showed acalculus cholecystitis with extensive diffuse infiltrates of numerous eosinophils and T lymphocytes, but sparse polymorphonuclear leukocytes. The authors name this unusual cholecystitis acalculus lymphoeosinophilic cholecystitis and believe it to be associated with interleukin-2 and lymphokine-activated killer cell therapy. The pathogenic relationship is discussed.

Cholecystitis↗
PubMed1990

Tamoxifen potentiates in vivo antitumor activity of interleukin-2.

Tamoxifen, an antiestrogen with efficacy in treatment of both estrogen receptor-positive and negative breast tumors, may be immunomodulatory. We tested tamoxifen's ability to augment the antitumor activity of interleukin-2 (IL-2), a lymphokine capable of expanding and activating lymphocytes, in the treatment of established pulmonary metastases of the weakly immunogenic murine fibrosarcoma MCA-106. Age-matched C57BL/6 female mice bearing pulmonary metastases induced by a tail vein injection of MCA-106 tumor suspension (5 x 10(5) cells/mouse) were treated from days 3 through 12 with intraperitoneal saline solution or IL-2 (50,000 units twice a day). Half of the mice in each group received plain and the remainder received tamoxifen-treated (2 units/ml) drinking water ad libitum for the duration of the experiment. All mice were killed on day 18 for enumeration of pulmonary metastases. Compared with saline-treated control mice, IL-2 and tamoxifen reduced metastases by 66% (p less than 0.0002) and 30% (p less than 0.005), respectively. IL-2 and tamoxifen combined reduced metastases 95% (p less than 0.0002), significantly better than did IL-2 (p less than 0.02) or tamoxifen (p less than 0.0003) alone. In vitro, tamoxifen inhibited proliferation of the weakly estrogen receptor-positive MCA-106 tumor by approximately 30%. Tamoxifen had no effect on the generation of 3-day IL-2-activated lymphocyte cytotoxicity against both natural killer-sensitive (YAC) and natural killer-resistant (MCA-106) target cells. Both YAC and MCA-106 tumor became more resistant to lysis with increased concentration of tamoxifen. This is the first demonstration of in vivo potentiation of IL-2 antitumor activity by tamoxifen and suggests its possible use clinically.

Animals↗
PubMed1989

Interleukin-2 and alpha interferon therapy of advanced pulmonary metastases.

Pulmonary metastases of a weakly immunogenic methylcholanthrene-induced murine fibrosarcoma MCA-106 were treated on day 10 for 10 days with saline, interleukin-2 (IL-2), hybrid recombinant interferon A/D (rIFN A/D) or the combination. IL-2/IFN effected greater than 99% reduction in tumor compared to saline, IL-2 or IFN alone. However, IL-2/IFN also resulted in early (less than 25 days) mortality of 33% in two consecutive experiments. Excluding these early deaths, a significant prolongation of survival resulted in 1 long-term survivor (greater than 150 days). Interruption of the 10-day treatment with a 2-day rest at 5 days abrogated early mortality, but despite significant prolongation of survival, no long-term survivors were seen. These data suggest possible clinical application of IL-2/IFN in the treatment of advanced tumor metastases but cautions of increased treatment toxicity associated with this regimen.

Animals↗
PubMed1989

Profound hypothermia and circulatory arrest for aneurysm surgery. Case report.

Direct surgical repair of technically difficult or otherwise inoperable vascular lesions of the brain may become possible or safer using profound hypothermia and circulatory arrest. Most surgeons who use this technique establish extracorporeal circulation by cannulating the femoral vessels. To avoid difficulties associated with this closed chest method, a method was devised to establish extracorporeal circulation, profound hypothermia, and circulatory arrest by direct cannulation of the right atrium and aorta through the chest. This technique is described in a patient whose otherwise inoperable vertebral artery aneurysm was successfully treated. This approach is simple and offers several advantages over the closed chest method.

Adult↗