PURPOSE: To analyze the acute histologic change of extraocular muscles (EOM) induced by injection of bupivacaine or Ricin mAb 35. METHODS: The superior rectus and inferior rectus of white rabbits were injected with either bupivacaine (0.4 mg in 0.3ml) or Ricin mAb 35 (0.2 micro gram/kg in 0.3 ml). One, two, and four weeks after injection, the rectus muscles were harvested and the post-injection changes were histologically analyzed. RESULTS: Both the orbital and the global layers of EOM showed myotoxic changes induced by bupivacaine and Ricin mAb 35. However, the inflammation and destruction of myofiber by bupivacaine injection were localized to the injection site, whereas changes induced by Ricin mAb 35 were diffuse. Regenerating myofibers with a central nucleus were found at one week after myotoxin injection. Four weeks after injection, the acute changes induced by these two toxins were much recovered with prominent myofiber regeneration. Bupivacaine-induced myotoxic change was more prominent in the global layer in contrast to the more prominent damage in the orbital layer induced by Ricin mAb 35. CONCLUSIONS: We found that EOM have a superb ability to recover from the acute injury induced by bupivacaine or Ricin mAb 35 and that the two myotoxins cause unique damage including the predilection of muscle layers and the duration for which the damage persisted. Further investigation into the functional change during recovery from the myotoxin-induced injury of EOM is needed.
Bupivacaine* ; Inflammation ; Muscles ; Orbit ; Rabbits* ; Regeneration ; Ricin*

Animals ; Cytoplasm ; metabolism ; Endoplasmic Reticulum, Rough ; metabolism ; Golgi Apparatus ; metabolism ; Humans ; Protein Transport ; Ricin ; chemistry ; pharmacokinetics ; therapeutic use

OBJECTIVETo observe the significance of ricin (RT) with chemical nidification to reduce the hepatotoxicity in mice and its anticancer effect.

METHODSMice were exposed to RT and RT-PDP [ricin chemically modified by N-succinimidyl 3-(2-pyridyldithio)-propionate, (SPDP)] respectively, and their serum activity of glutathione-S-transferase (GST) and liver glutathione (GSH) content were determined. The ultramicro-structure under electron microscope was also observed.

RESULTSThe GST activity increased with doses, and the increase in ricin group was higher than that in RT-PDP group; the activities of GST in RT group at 12.5, 15.0 micro g/kg [(93.65 +/- 12.30), (153.71 +/- 26.64) IU/L respectively] were higher than those in RT-PDP group [(62.97 +/- 11.22), (78.20 +/- 15.71) IU/L] (P < 0.05). The contents of GSH were decreased with doses; but the contents of GSH in RT-PDP group at 2.5, 5.0, 7.5, 10.0, 15.0 micro g/kg [(6.34 +/- 1.43), (4.14 +/- 1.82), (3.54 +/- 0.64), (2.73 +/- 1.82), (1.82 +/- 0.62) micro mol/L respectively] were still higher than those in RT group [(3.53 +/- 0.95), (2.12 +/- 0.54), (1.82 +/- 0.71), (1.52 +/- 0.34), (0.81 +/- 0.36) micro mol/L] (P < 0.01). Electron microscopic examination showed that the injury of liver cells in RT group was more severe than that in RT-PDP group.

CONCLUSIONThe hepatotoxicity of ricin in mice may be reduced by chemical modification.

Animals ; Chemical Warfare Agents ; toxicity ; Female ; Glutathione ; metabolism ; Glutathione Transferase ; metabolism ; Liver ; drug effects ; metabolism ; ultrastructure ; Male ; Mice ; Microscopy, Electron ; Ricin ; analogs & derivatives ; toxicity

Colony-Forming Units Assay ; Cryopreservation ; methods ; Fetal Blood ; cytology ; Hematopoietic Stem Cells ; cytology ; Humans ; Immunotoxins ; immunology ; Leukocytes, Mononuclear ; cytology ; Ricin ; immunology ; T-Lymphocytes ; cytology ; immunology ; Time Factors

OBJECTIVETo study the expression and purification of a fusion protein of ricin A chain (RTA) and green fluorescent protein (GFP).

METHODSThe DNA sequence encoding ricin A chain was inserted into pEGFPC1 first to make the template sequence of the fusion protein. The fusion gene was amplified from the plasmid pEGFP-RTA by PCR, and directly subcloned into T vector. The fusion gene then was cloned into expression vector pET-28a(+), and the sequence was confirmed by sequencing. Expression was induced by IPTG in E. coli BL21(DE3). The fusion protein was purified by metal chelated affinity chromatography. The cytotoxicity of fusion protein was analyzed by the MTT assay in HepG2 and Hela cells.

RESULTSThe fusion protein of ricin A chain and GFP could be produced in E. coli transformed with the expression plasmid of pET-28a(+)-GFP-RTA. The molecular weight of the recombinant protein was measured by SDS-PAGE. The fusion protein showed a green fluorescence and had a similar cytotoxicity of RTA.

CONCLUSIONA recombinant fusion protein of RTA and GFP expressed in E. coli is possessed of similar biological activity of individual GFP and RTA, which could be used in study of the intracellular trafficking and translocation of RTA.

Escherichia coli ; genetics ; metabolism ; Green Fluorescent Proteins ; genetics ; HeLa Cells ; Humans ; Luminescent Proteins ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; Ricin ; genetics

OBJECTIVETo study lysosomes involvement in the degradation of ricin A chain.

METHODSA lysosome-targeted singal KFERQ was added to the C terminus of rRTA by DNA recombinant technology. A pKK223.3 expression system in E. coli was used to produce recombinant ricine A chain (rRTA) and rRTA-KFERQ. Recombinant proteins were purified by affinity chromatography using Blue-Sepharose 6B. The cytotoxicity of recombinant proteins was measured by the MTT method.

RESULTSRecombinant RTA-KFERQ was 49.87%, 54.18% and 88.68% less cytotoxic than RTA itself on the three cell lines HEPG2, Hela and A549, respectively.

CONCLUSIONLysosomes can degrade, but not completely inactivate RTA in different cells, suggesting cells may have other degradation pathways for RTA.

Chromatography, Affinity ; Escherichia coli ; genetics ; metabolism ; HeLa Cells ; Humans ; Lung Neoplasms ; pathology ; Lysosomes ; metabolism ; Recombinant Proteins ; genetics ; isolation & purification ; metabolism ; Ricin ; genetics ; metabolism ; Tumor Cells, Cultured

This study was aimed to investigate the clinical outcome of ricin-immunotoxin mediated T cell partially depleted HLA/MLC mismatched allogeneic hematopoietic stem cell transplantation. 13 patients with hematological malignancies were treated by ricin-immunotoxin mediated T cell partially depleted allogeneic hematopoietic stem cell transplantations from HLA/MLC mismatched donors, including 6 cases of CML in CP(1), 1 case of ALL in CR(1), 1 case of ALL in CR(2), 1 case of ALL in relapse, 2 cases of AML in CR(1), 1 case of AML in CR(2), 1 case of MDS-RAEBT-AML (M(4)) in CR(1). The results showed that 8 cases were engrafted successfully, 2 cases of them developed grade II acute GVHD and 2 cases developed grade III-IV acute GVHD. Within following-up of 8 - 90 months, 2 patients who experienced grade III-IV acute GVHD died early after transplantation; 1 patient died of late onset of infection; the other 5 patients survived free from diseases. After failure at first infusion, 4 patients were given reinfusion of peripheral blood hematopoietic stem cells from the same donor. 3 out of 4 cases failed to engraft and only one patient got engraftment but died of related complications of transplantation. One patient was performed a second transplantation from a syngeneic donor and survive free of disease until now. In conclusion, T cell partially depleted HLA/MLC mismatched allogeneic hematopoietic stem cell transplantation by ricin-immunotoxin decreases the occurrence of severe acute GVHD but with high risk of rejection, which clinical outcome still needs further evaluation.
Adolescent ; Adult ; Child ; Female ; Graft vs Host Disease ; epidemiology ; Hematopoiesis ; Hematopoietic Stem Cell Transplantation ; mortality ; Humans ; Immunotoxins ; pharmacology ; Lymphocyte Depletion ; methods ; Male ; Ricin ; pharmacology ; T-Lymphocytes ; drug effects ; Transplantation, Homologous

OBJECTIVETo extract and purify ricin from castor beans and to evaluate its anti-cancer activity.

METHODSRicin was purified from castor beans according the modified method of Nicolson and Blaustin. The lectins were extracted in 0.01 mol/L phosphate buffered saline and isolated in the 40% to 80% fraction of ammonium sulfate precipitation. The dialyzed fractionated preparation was applied with a Sepharose 4B column. The lectins were eluted with a linear lactose gradient (0.01 mol/L approximately 0.5 mol/L). Ricin was separated from the ricinus agglutinin by gel filtration on a Sephadex G-100. MTT was applied to analyze the cytotoxicity with different dosage of ricin in different cancer cell lines.

RESULTSThere was no difference between the killing effect of normal cells and that of colon cancer cells by using the high dosage of ricin (5 x 10(-8) mol/L approximately 5 x 10(-10) mol/L). However, the cytotoxicity was significant different in those cells with the low dosage of ricin (5 x 10(-11) mol/L approximately 5 x 10(-13) mol/L). Meanwhile ricin had the similar cytotoxicity to leukemia cell K562 and colon cancer cell SW480.

CONCLUSIONRicin is able to kill tumor cells selectively at low concentration, but the selectivity does not appear at high concentrations.

Animals ; Antineoplastic Agents, Phytogenic ; pharmacology ; Cell Line, Tumor ; Colorectal Neoplasms ; pathology ; Dose-Response Relationship, Drug ; Humans ; K562 Cells ; Male ; Mice ; Rats ; Rats, Sprague-Dawley ; Ricin ; isolation & purification ; pharmacology ; T-Lymphocytes, Cytotoxic

OBJECTIVETo explore the effect of ricin temperature response gel on breast cancer and its regulatory effect on immune function in rats.

METHODSRicin was purified by chromatography and identified by immunoblotting. The rat subcutaneously transplanted breast cancer model was established. Forty model rats with a tumor diameter of about 3.0 cm were subjected to the study. They were randomized into four groups equally: the model group and three treated groups (blank gel, ricin, ricin-gel) were administered with blank gel, ricin, and ricin temperature response gel via percutaneous intratumor injection, respectively. The tumor was isolated 10 days later for the estimation of tumor inhibition rate (TIR) by weighing, pathologic examination, and detection of tumor apoptosis-associated genes bcl-2 and bax with semiquantitative RT-PCR. Also, peripheral blood was obtained to test T-lymphocyte subsets, the killing function of lymphocytes, and the contents of tumor necrosis factor-α (TNF-α) and interleukin-2 (IL-2). The outcomes were compared between groups.

RESULTSThe TIR in the ricin-gel group was 61.8%, with the pathologic examination showing extensive tumor tissue necrosis. Compared with the model group, after ricin temperature response gel treatment, bcl-2 expression was down-regulated, bax expression was up-regulated, CD4+ lymphocytes and CD4+/CD8+ ratio in peripheral blood were increased, the killing function of lymphocytes was enhanced, and the contents of TNF-α and IL-2 were elevated (P < 0.05 or P < 0.01).

CONCLUSIONIntratumor injection of ricin temperature-responsive gel showed significant antitumor effect on breast cancer and could enhance the immune function in the tumor-bearing rat.

Animals ; Antineoplastic Agents ; administration & dosage ; Apoptosis ; drug effects ; CD4-CD8 Ratio ; Disease Models, Animal ; Female ; Gels ; therapeutic use ; Immunohistochemistry ; Immunomodulation ; drug effects ; Injections, Intralesional ; Interleukin-2 ; immunology ; metabolism ; Mammary Neoplasms, Experimental ; drug therapy ; immunology ; pathology ; Random Allocation ; Rats ; Rats, Wistar ; Ricin ; administration & dosage ; Sensitivity and Specificity ; Temperature ; Tumor Necrosis Factor-alpha ; immunology ; metabolism