Survival Analysis of Escherichia coli Encapsulated in a Hollow Fiber Membrane In Vitro and In Vivo: Preliminary Report

The purpose of the observations was the viability and quality evaluation of E. coli bacteria encapsulated in hollow fiber membranes (HF) in short in vivo and in vitro experiments. A polypropylene, surface-modified hollow fiber was applied for immunoisolation of E. coli bacteria transfected with a green fluorescent protein (E. coli GFPI). The presence of GFP fluorescence of organisms was assessed with the use of flow cytometry. The E. coli GFPIs were then observed for the period of 5 days in in vitro experiments in the culture medium. A single IPTG (isopropyl β-D-1-thiogalactopyranoside) induction of GFP gene appeared to be adequate for an expression of GFP protein for 5 days. The GFP expression values observed for E. coli GFPs encapsulated in HF during culture in different culture media were comparable. The survival of E. coli GFPIs encapsulated in HF after 1, 2, 4, or 5 days of subcutaneous implantation into mice was evaluated. The explanted E. coli GFPIs exhibited mean expression 603 ± 17 (n = 32) units of fluorescence during the implantation period. The values obtained were comparable for selected days of observation. It was observed that the membranes applied ensured the bacteria growth within the HF's space only.

Human lymphocytic B-leukemia cell line treatment with the bacterial toxin listeriolysin O and rituximab (anti-CD20 antibody): Effects of similar localization of their receptors

Small B-cell lymphocytic lymphoma/chronic lymphocytic leukemia, which typically affects elderly people, is a group of conditions that are not clinically uniform. It has been suggested that using the combined activity of the monoclonal antibody anti-CD20 (rituximab) and Listeria monocytogenes toxin listeriolysin O (LLO) for this condition could produce an enhanced treatment effect. Here, we tested the effect of the joint activity of rituximab and LLO, which is a cell membrane toxin, in human leukemia cell lines. The human B-leukemia Raji cell line, which expresses CD20, and the T-cell Jurkat cell line, which does not express CD20, for comparison were used in model tests. Cell cytotoxicity of rituximab or LLO and both applied jointly to the cell lines was compared in the presence of human plasma complement. Optimal cytotoxic effects dependent on rituximab or LLO concentration were tested separately. LD50 values were determined and used for optimal application of a mixture of the two factors. The cytotoxic effect on Raji cells of both rituximab and LLO was more than 2.5 times that of LLO alone and 1.5 times that of rituximab alone. At the highest tested concentrations, a mixture of the tested factors had a non-specific cytotoxic effect on the Jurkat cell line, as well. The rituximab and LLO binding sites appear to be in a similar region of the Raji leukemia cell membrane, suggesting an effective interaction of both factors. The joint interaction of these compounds in cell membrane pore formation suggests an explanation for the more effective cytotoxic activity that their combination was observed in this experiment.

Biocompatibility of electrospun human albumin: a pilot study

Albumin is rarely used for electrospinning because it does not form fibres in its native globular form. This paper presents a novel method for electrospinning human albumin from a solution containing pharmaceutical grade protein and 25% polyethylene oxide (PEO) used as the fibre-forming agent. After spontaneous cross-linking at body temperature, with no further chemicals added, the fibres become insoluble and the excess PEO can be washed out. Albumin deposited along the fibres retains its native characteristics, such as its non-adhesiveness to cells and its susceptibility for degradation by macrophages. To demonstrate this we evaluated the mechanical properties, biocompatibility and biodegradability of this novel product. After subcutaneous implantation in mice, albumin mats were completely resorbable within six days and elicited only a limited local inflammatory response. In vitro, the mats suppressed cell attachment and migration. As this product is inexpensive, produced from human pharmaceutical grade albumin without chemical modifications, retains its native protein properties and fulfils the specific requirements for anti-adhesive dressings, its clinical use can be expedited. We believe that it could specifically be used when treating paediatric patients with epidermolysis bullosa, in whom non-healing wounds occur after minor hand injuries which lead to rapid adhesions and devastating contractures.

Cytotoxicity of listeriolysin O produced by membrane-encapsulated Bacillus subtilis on leukemia cells

Encapsulation of biological material in the permiselective membrane allows to construct a system separating cells from their products, which may find biotechnological as well as biomedical applications in biological processes regulation. Application of a permiselective membrane allows avoiding an attack of the implanted microorganisms on the host. Our aim was to evaluate the performance of Bacillus subtilis encapsulated in an elaborate membrane system producing listeriolysin O, a cytolysin from Listeria monocytogenes, with chosen eukaryotic cells for future application in anticancer treatment. The system of encapsulating in membrane live Bacillus subtilis BR1-S secreting listeriolysin O was proven to exert the effective cytotoxic activity on eukaryotic cells. Interestingly, listeriolysin O showed selective cytotoxic activity on eukaryotic cells: more human leukemia Jurkat T cells were killed than human chronic lymphocytic B cells leukemia at similar conditions in vitro. This system of encapsulated B. subtilis, continuously releasing bacterial products, may affect selectively different types of cells and may have future application in local anticancer treatment.

Repair of Articular Cartilage Defects With Cultured Chondrocytes on Polysulphonic Membrane: Experimental Studies in Rabbits

INTRODUCTION

Autologous osteochondral transplantation is one method that can be used to create hyaline or hyaline-like repair in a defect area. The purpose of the present study was to repair full-thickness articular cartilage defects in 9 rabbit knee joints with autologous cultured chondrocytes.

METHODS

An articular cartilage defect was created on the patellar groove of the femur. The defect was filled with chondrocytes cultured in vitro and placed into the knee on a polysulphonic membrane. At 8 weeks after the operation, the reparative tissue was analyzed macroscopically and histologically.

RESULTS

At 8 weeks after the operation, the surfaces of the reparative tissue were smooth, and the defects were filled with mature hyaline cartilage in 5 cases. In 2 cases, the reparative hyaline cartilage was immature and there was worse integration of grafted tissue into the adjacent normal cartilage. In 2 cases, the surface of the grafted area was irregular, and the reparative tissue was disintegrated and incompletely differentiated.

CONCLUSION

The results suggest that transplantation of autologous chondrocytes cultured in vitro and placed into the knee on polysulphonic membrane is effective in repairing an articular cartilage defect.

Flow cytometry analysis of the activity of disinfecting agents tested with Staphylococcus aureus and Escherichia coli

The efficacy of five disinfecting agents was tested by a new microbiological method, i.e. the flow cytometry. The method is based on kinetic measurements of the effects of a disinfecting agent on the percent of live/dead cells detected with propidium iodide. E. coli ATCC52922 strain and S. aureus ATCC 29213 strain were used in the experiment. From the measurements the killing time 50 (KT50) was estimated as the period of time needed to kill 50% of microorganisms in the disinfected volume. KT50 for ethanol 70% was 11s and it was the most efficient disinfecting agent among all examined. Other commercial preparations were compared with ethanol 70% and were traced throughout the period of 5 min. The results were obtained rapidly, frequently in less than 10 min. In conclusion, the effectiveness of a particular antibacterial disinfectant preparation may be estimated quantitatively within a few minutes by the flow cytometry. The method proved to be very useful for a fast comparison of the effectiveness of various disinfectant preparation against pathological microorganisms.

Membrane for immunoisolation--properties before, and post implantation: preliminary report

The membranes preventing tissue overgrowth as well as toxic influence on cells encapsulated within can be obtained modifying the polypropylene membranes by silanization. The influence of the silanization with different siloxanes on membrane transport properties was assessed before and post implantation. No change in cut-off values was observed. All of the modified membranes delayed tissue overgrowth of implant in mouse. Spectroscopic evaluation of the membrane material after 4, 7 days, 2 and 4 months of implantation revealed membrane material stability. We concluded that evaluated membranes with cells encapsulated within may be applied as the systems for delivery of biologically active substances.

Evaluation of a system producing the hemopoietic factor. WEHI-3B cell line function, when encapsulated in a polypropylene hollow fibre

The purpose of our study was evaluation of functioning of WEHI-3B (an mouse cell line producing IL-3) cells encapsulated in hollow fibers (HF). In vitro: the WEHI-3B cells were encapsulated in HF of polypropylene K600 silikonized, and cultured over two weeks. In vivo: the encapsulated WEHI-3B after weeks culture, were implanted subcutaneously into mice for 1 week. After explantation encapsulated WEHI 3-B were cultured again in culture medium for one week. The production of IL-3 by encapsulated WEHI-3B cells was assessed by evaluation of IL-3 dependent, BaF3 cells viability. The percent number of one day survival of BaF3 cells in the culture medium supplemented with 15% of encapsulated WEHI-3B in vitro or encapsulated WEHI-3B after in vivo conditioned medium was comparable with positive control. Possible replacement of recombinant cytokines with HF encapsulated cytokine-producing cells may be a chance for continous supplementation of the factors for hematopoietic stem cells differentiation.

Hematological effects of intermittent 2-hour infusions of cladribine in multiple sclerosis patients: a comparison of 2 dosage patterns

Cladribine is a lymphocytotoxic purine nucleoside with potential for treatment of autoimmune diseases. However, optimal administration regimens remain to be established. Twenty multiple sclerosis patients enrolled into this study were given 30 intermittent 2-hour cladribine infusions (0.07 mg/kg per infusion) each. Ten patients received cycles of 5 consecutive daily infusions at 5-week intervals (clustered dosage) on an inpatient basis; the other 10 patients received 1 infusion weekly (nonclustered dosage) on an outpatient basis. Red blood cell (RBC), platelet, and total white blood cell (WBC) counts were assessed at 5-week intervals during the treatment and at 13-week intervals during a 26-week follow-up period. Major WBC and lymphocyte subsets were assessed cytometrically at 15-week intervals during the treatment and at 13-week intervals thereafter. The clustered dosage produced a lasting decline in granulocyte count, a delayed decrease in monocyte count, and a transient decrease in RBC count. The nonclustered dosage caused a larger and persistent decline in RBC count, a smaller (P = .051. compared over the study period) decrease in monocyte count, and no change in granulocyte count. Both regimens transiently reduced natural killer and B-cell subsets (by 40%-60% and >80%, respectively) and caused lasting declines in CD4+ T-cell subsets (by >50%). No significant change was found in CD8+ T-cell subsets. These results show similar potency of these regimens with respect to major lymphocyte subsets, while suggesting that the nonclustered dosage is less toxic to myeloid precursors and more toxic to erythroid lineage precursors.

T-cell subtypes in bronchoalveolar lavage fluid and in peripheral blood from patients with primary lung cancer

The changes in local immunology play an important role in lung cancer development. We used bronchoalveolar lavage fluid (BALF) and peripheral blood (PB) for the analysis of cell profiles in patients with primary lung cancer. Twenty-one patients with confirmed primary lung cancer and 13 healthy volunteers were investigated. All persons were smokers. The analysis of T-cell subsets was performed with a flow cytometry method and with the following antibodies: anti CD3, CD4, CD8, CD16, CD25, CD45, CD56, and HLA-DR. We found differences in the proportion of lymphocytes between BALF and PB, and a higher proportion of T cells and a lower proportion of B and natural-killer (NK) cells in BALF. There was a significant difference in the proportion of T-cytotoxic/suppressor lymphocytes, which was elevated in the BALF of patients and decreased in patients' PB. The T-helper:T-cytotoxic/suppressor (Th:Tc/s) ratio was significantly lower in the BALF of patients. These changes were visible in patients with a small cell type. The percentage of T cells with the alpha chain of receptor to IL-2 (IL -R) was lower in the BALF of patients than in the control group. Our observations reflect local changes in lung environment in patients affected with lung cancer.

[Adverse effects of parenteral administration of antisense oligonucleotides]

To characterize the toxicity of phosphorothioate antisense oligodeoxynucleotides ([S]ODNs) in vivo, the mice received intravenously 26-mer bcr-abl antisense oligodeoxynucleotides (1 mg/mice/day) for 9 consecutive days. The organs and tissues were removed on the indicated days (+1, +7, +30) after the treatment. Our investigation revealed middle elevation of aminotransferases activity, lactate dehydrogenase level, total protein level and globulin level, decrease of glucose, albumin and blood urea nitrogen level in the peripheral blood. The mild anaemia and thrombocytopenia were observed too. The most significant treatment-related findings in the antisense treated mice were splenomegaly, reactive hepatitis and atrocytosis of kidney. These findings together with previous results demonstrate little and temporary toxicity effects mainly in organs known from cumulating of [S]ODNs.

Encapsulation of parathyroid cells in hollow fibers: a preliminary report

The purpose of experiments was to evaluate the survival and functioning of human parathyroid cells after encapsulation in hollow fibers (HFs). The polypropylene HFs K600(PP Accurel (Akzo-Nobel, Germany) of inner diameter 0.6 mm, wall thickness 0.2 mm, original or surface modified were used for encapsulation. Production of parathormone (PTH) by encapsulated cells was measured in vitro. HF were filled with parathyroid cell suspension and tightly closed. Encapsulated cells were cultured for 9 or 33 days in RPMI 1640 containing 10% FCS or in Chang's medium. The level of PTH, produced by encapsulated cells was evaluated in the culture medium with radioimmunoassay test (RIA). The assays were performed every 2-4 days. The result of PTH assay was similar in both types of tested media as well as with unmodified and modified HFs, being 2-4 pg/ml of culture medium per 10(3) encapsulated cells. In conclusion, encapsulation in original or modified HFs ensures diffusion of nutrients from culture medium to encapsulated cells and allows for functioning of cells for at least 33 days in vitro.

Effects of an inhibitor of tripeptidyl peptidase II (Ala-Ala-Phe-chloromethylketone) and its combination with an inhibitor of the chymotrypsin-like activity of the proteasome (PSI) on apoptosis, cell cycle and proteasome activity in U937 cells

AAF-AMC is not a specific TPP II substrate, since it is also hydrolyzed by purified proteasomes. Moreover, AAF-cmk, claimed to be a specific TPP II inhibitor, also inhibits the chymotrypsin-like activity of the proteasome. While AAF-cmk itself is mildly cytostatic to U-937 cells and induces cell cycle block in G1, its combination with PSI does not induce an increase in the cytostatic/cytotoxic effects. This suggests that TPP II is possibly less important for cell metabolism than it was previously believed and it is less probable that it can be able to fully compensate for the loss of the proteasome function.

Granulocyte-macrophage colony-stimulating factor potentiates antitumor activity of interleukin-12 in melanoma model in mice

To study the antitumor activity of the combination immunotherapy with interleukin-12 (IL-12) and granulocyte-macrophage colony-stimulating factor (GM-CSF), a murine MmB 16 melanoma tumor model was used. Seven days after inoculation of MmB 16 melanoma cells into the footpad of the right hind limb, mice were treated with IL-12 and/or GM-CSF administered intratumorally for 7 consecutive days. IL-12 used both at a high (1 microg) and at a low (0.01 microg) dose per day produced retardation of tumor growth, although neither treatment resulted in any significant prolongation of the survival of tumor-bearing mice. GM-CSF did not by itself exert antitumor activity in this model; however, it potentiated antitumor effects of IL-12. In particular, survival of tumor-bearing mice treated with IL-12 (0.01 microg per day) and GM-CSF was significantly prolonged compared with that in mice treated with either IL-12 or GM-CSF alone.

Effect of Baypamun on blood leucocytes in normal and dexamathasone treated goats

The aim of this study was to determine the effect of Baypamun on selected lymphocyte subpopulations and granulocyte phagocytic activity mediated by lectin-like receptors in goats of normal immune status and in goats experimentally immunosuppressed with dexamethasone. Eighteen goats in total were used. Blood samples were collected 24 h before immunomodulation and 5 and 10 days after immunomodulation. Animals in group I were immunostimulated with Baypamun for 2 days and immunosuppressed with Dexafort for the next 2 days. Animals in group II received Dexafort first and then Baypamun. The number of leucocytes in total and in subpopulations was determined by flow cytometry. Application of Baypamun before (group I) or after (group II) immunosuppression caused significant (P < 0.001) and lasting changes in the percentage of CD2+, CD4+ and CD8+ T cells. Significant but transient changes were observed in CD19+ (B) and WC1-N2+ (null) cells. Results show that application of Baypamun to modulate non-specific defence is advisable following immunosuppression (group I). When Baypamun was applied after immunosuppression (group II), although there was no reaction during the initial phase, an increase in the activity of cells responsible for non-specific immunity was noticeable after 10 days.

Flow cytometry analysis of milk and peripheral blood cells from goats during lactation

Cells from goat's milk and peripheral blood taken during the lactation period were analysed by flow cytometry. The investigated cells were populations of leucocytes, lymphocyte subpopulations (T, T-helper, T-cytotoxic, B, WC1-N2) and all MHC class II positive cells. Labelling of cells was performed on whole blood and milk cell suspensions. Statistically significant differences were found between percentages of B and WC1-N2 lymphocytes and MHC II positive cells from peripheral blood during the lactation period and all of examined milk cells during the same time.

Flow cytometric evaluation of lymphocyte subpopulations in BALF of healthy smokers and nonsmokers

The purpose of this work was to evaluate the normal lymphocyte phenotype in the bronchoalveolar lavage fluid (BALF). BAL was carried out in 12 untreated healthy nonsmoking volunteers and in 9 cigarette smokers. For the analysis of lymphocyte subsets by two-color flow cytometry, the monoclonal antibodies used were directed anti: CD3, CD4, CD8, CD16, CD19, D25, CD45, CD56 and anti HLA-DR. An increase in the total number of cells in BALF of smoking persons and increased proportion of macrophages was observed. The percentage of CD8+ lymphocytes was 1.7 times higher, whereas the proportions of CD4+ cells, and a CD4+/CD8+ ratio were lower 1.5 and 2.6 times, respectively, in the BALF of cigarette smoking persons when compared with nonsmoking volunteers. The changes did not depend on the age of the person. In conclusion, we suggest that the decreased CD4/CD8 ratio and the elevated CD8 T cell subset may be regarded as a potential risk factor associated with clinically asymptomatic lung cancer. Moreover, in the interpretation of BALF from patients with pulmonary diseases cell proportions of nonsmoking and of smoking persons should be compared with the respective controls.

Interstitial lung disease in systemic sclerosis: comparison of BALF lymphocyte phenotype and DLCO impairment

Patients with scleroderma (systemic sclerosis-SSc) frequently develop an interstitial lung disease. The role of lymphocytes in fibrosing alveolitis preceding lung fibrosis has been established. The purpose of this work was to evaluate cell profiles and lymphocyte phenotypes in the bronchoalveolar lavage (BAL) fluid and to correlate them with depression in lung function tests detected by depletion of diffusing capacity (DLCO). BAL was carried out in 25 untreated, non-smoking patients suffering from diffuse scleroderma and in 12 healthy non-smoking volunteers. For the analysis of lymphocyte sub-sets flow cytometry and monoclonal antibodies were used. The following cell sub-types were counted: T lymphocytes, B lymphocytes, helper lymphocytes, suppressor/cytotoxic lymphocytes, natural killer cells, cytotoxic T lymphocytes and activated T lymphocytes. The total cell count was higher in the group of patients with mild and moderate impairment in DLCO. The percentage of lymphocytes was greater in patients with DLCO lower than 65% of the predicted value since neutrophilia was found in patients with severe DLCO depletion, i.e. significant when compared with healthy subjects. The proportions of suppressor/cytotoxic lymphocytes and of activated T lymphocytes were higher in patients than in controls. The statistical analysis revealed significant differences between patients with moderate and mild changes in DLCO and the healthy volunteers. A decreased helper/suppressor ratio was noticed in these patients. We concluded that the BALF lymphocyte phenotype analysis may reflect the features of alveolitis in patients with SSc.

Apoptosis and some of its medical implications

The following phases of apoptosis were proposed: decisive, executive and degradation. At least two checkpoints are recognized in the process of apoptosis: the p53 and Bcl-2/Bax protein family checkpoint and the protease-caspase and serine protease checkpoint. Signals to apoptosis from outside of the cell including Fas and Fas ligand interaction and sphingomyelin cycle were presented. Cellular morphological events in apoptosis: DNA chain breaks, changes in cell membrane and mitochondrial membranes were discussed. Some medical problems of cardiology in which apoptosis plays an important role were presented. The cancer treatment results depending on apoptosis of cancer cells were discussed as well.

Role of p53 in hematopoietic recovery after cytotoxic treatment

Prompt reconstitution of hematopoiesis after cytoreductive therapy is essential for patient recovery and may have a positive impact on long-term prognosis. We examined the role of the p53 tumor suppressor gene in hematopoietic recovery in vivo after treatment with the cytotoxic drug 5-fluorouracil (5-FU). We used p53 knock-out (p53-/-) and wild-type (p53+/+) mice injected with 5-FU as the experimental model. Analysis of the repopulation ability and clonogenic activity of hematopoietic stem cells (HSCs) and their lineage-committed descendants showed a greater number of HSCs responsible for reconstitution of lethally irradiated recipients in p53-/- bone marrow cells (BMCs) recovering after 5-FU treatment than in the corresponding p53+/+ BMCs. In post-5-FU recovering BMCs, the percentage of HSC-enriched Lin- Sca-1(+) c-Kit+ cells was about threefold higher in p53-/- than in p53+/+ cells. Although the percentage of the most primitive HSCs (Lin- Sca-1(+) c-Kit+ CD34(low/-)) did not depend on p53, the percentage of multipotential HSCs and committed progenitors (Lin- Sca-1(+) c-Kit+ CD34(high/+)) was almost fourfold higher in post-5-FU recovering p53-/- BMCs than in their p53+/+ counterparts. The pool of HSCs from 5-FU-treated p53-/- BMCs was exhausted more slowly than that from the p53+/+ population as shown in vivo using pre-spleen colony-forming unit (CFU-S) assay and in vitro using long-term culture-initiating cells (LTC-ICs) and methylcellulose replating assays. Clonogenic activity of various lineage-specific descendants was significantly higher in post-5-FU regenerating p53-/- BMCs than in p53+/+ BMCs, probably because of their increased sensitivity to growth factors. Despite all these changes and the dramatic difference in sensitivity of p53-/- and p53+/+ BMCs to 5-FU-induced apoptosis, lineage commitment and differentiation of hematopoietic progenitors appeared to be independent of p53 status. These studies suggest that suppression of p53 function facilitates hematopoietic reconstitution after cytoreductive therapy by: (1) delaying the exhaustion of the most primitive HSC pool, (2) stimulating the production of multipotential HSCs, (3) increasing the sensitivity of hematopoietic cells to growth factors, and (4) decreasing the sensitivity to apoptosis.

Lymphocyte phenotyping in systemic sclerosis: a flow cytometry analysis of lymphocytes in bronchoalveolar lavage fluid

OBJECTIVE

Patients with scleroderma (systemic sclerosis [SSc]) frequently develop interstitial lung disease. The purpose of this work was to evaluate the cell profile in the bronchoalveolar lavage fluid (BALF) in patients suffering from a diffuse form of systemic sclerosis as compared with healthy controls.

STUDY DESIGN

Bronchoalveolar lavage was carried out in the right middle lobe of 25 untreated, nonsmoking patients with SSc and 12 healthy, nonsmoking volunteers. For the analysis of lymphocyte subsets, the following monoclonal antibodies were used: anti-CD3, anti-CD4, anti-CD8, anti-CD14, anti-CD16, anti-CD19, anti-CD25, anti-CD45, anti-CD56. Also, anti-HLA-DR and flow cytometry were used.

RESULTS

We found an increase in the total number of cells with an increase in the percentage of lymphocytes and neutrophils in BALF from patients when compared with controls (P < .05). The proportion of lymphocytes, cytotoxic/suppressor CD8+ and activated lymphocytes T CD25+ were higher in patients' BALF (P < .05). The CD4+/CD8+ ratio in BALF from subjects was significantly lower than in controls. These findings were characteristic of patients with early-stage disease.

CONCLUSION

Analysis of the BALF lymphocyte phenotype may be useful in the early detection of lung involvement in patients with SSc.

Treatment of Philadelphia leukemia in severe combined immunodeficient mice by combination of cyclophosphamide and bcr/abl antisense oligodeoxynucleotides

BACKGROUND

Philadelphia cells are human chronic myelogenous leukemia (CML) cells that contain the BCR/ABL oncogene (a fusion of the BCR and ABL genes). Selective eradication of these cells in vitro can be achieved by combined treatment with antisense phosphorothioate oligodeoxynucleotides ([S]ODNs) specifically targeted to this oncogene (bcr/abl [S]ODNs) and a suboptimal (for use as a single agent) dose of mafosfamide (the in vitro active form of cyclophosphamide).

PURPOSE

We evaluated the ability of bcr/abl antisense [S]ODNs, alone or subsequent to treatment with a single injection of cyclophosphamide, to suppress the leukemic process induced in severe combined immunodeficient (SCID) mice by Philadelphia cells (i.e., primary CML-blast crisis [CML-BC] cells). In addition, we studied potential mechanisms that might explain the efficacy of the bcr/abl antisense [S]ODN-mafosfamide combination against Philadelphia cells in vitro.

METHODS

The effects of treating leukemic mice with cyclophosphamide (25 mg/kg body weight; 25% of the dose required to eradicate evidence of leukemia in SCID mice) and/or bcr/abl antisense [S]ODNs were assessed by analysis of survival, by examination of bone marrow for the presence of leukemia cells (using a colony formation assay or using coupled reverse transcription and the polymerase chain reaction to screen for bcr/abl messenger RNA), and by examination of a variety of tissues for the presence of infiltrating leukemia cells. The induction of apoptosis (a cell death program) in vitro in primary CML-BC cells following treatment with bcr/abl antisense [S]ODNs plus or minus prior treatment with mafosfamide was monitored by use of a commercial assay. Relative cellular uptake of [S]ODNs by CML-BC cells treated in vitro with or without prior treatment with mafosfamide was determined by use of confocal microscopy and flow cytometry (for fluorescent [S]ODNs) or by use of blotting techniques that employed radioactively labeled probes (for extracted, unlabeled [S]ODNs). Levels of specific proteins in treated and untreated cells were determined by use of western blotting methods. Reported P values are two-sided.

RESULTS

The disease process in leukemic mice was retarded substantially by combination treatment with cyclophosphamide and specific bcr/abl antisense [S]ODNs (P < .001, relative to treatment with specific antisense [S]ODNs alone, cyclophosphamide alone, or cyclophosphamide plus nonspecific [i.e., control] antisense [S]ODNs); 50% of the mice treated with cyclophosphamide and specific antisense [S]ODNs appeared to be cured of leukemia. The combination treatment was associated with increased induction of apoptosis. In addition, cellular uptake of bcr/abl antisense [S]ODNs appeared to be increased twofold to sixfold by prior treatment with mafosfamide. This increased uptake of [S]ODNs was associated with enhanced suppression of p210bcr/abl protein levels.

CONCLUSIONS AND IMPLICATIONS

Combination therapy with antisense [S]ODNs targeted to specific oncogenes and less toxic doses of anticancer drugs may represent a rational strategy to purpose for the treatment of human leukemias.

Apoptosis induced in L1210 leukaemia cells by an inhibitor of the chymotrypsin-like activity of the proteasome

Of a number of factors involved in apoptosis, protease activity may play a crucial role. We show that N-benzyloxycarbonyl-Ile-Glu( O-t-butyl)-Ala-leucinal (PSI), a selective inhibitor of the chymotrypsin-like activity of the proteasome, induces massive apoptosis in murine leukaemia L1210 cells. At 50 nM concentration, PSI induces a block of cytokinesis, while higher concentrations (500 nM) cause S phase block and massive apoptosis. Z-Leu-leucinal, a specific calpain inhibitor, did not induce apoptosis. In contrast to previous reports, TNF-alpha did not enhance apoptosis when combined with PSI. Our results suggest that proteasome inhibitors may be considered as potential anti-neoplastic agents.

Populations of thymocytes and peripheral blood leucocytes in leukaemia-bearing mice treated with G-CSF

The influence of granulocyle-colony stimulating factor (G-CSF) on thymocyte subsets and peripheral blood leucocytes in leukaemia L1210-bearing mice was evaluated. Leukaemia-bearing mice have a markedly reduced L3T4+Lyt2+ thymocyte subpopulation. We observed "correction" of relative values of thymocyte subpopulations induced by treatment of mice with a G-CSF preparation. The suggestion is presented that this could result from liberation of lymphocyte T precursor cells from the bone marrow and increased homing of them into the thymus. The direct or indirect influence of G-CSF on the L3T4+Lyt2+ subpopulation of thymocytes is discussed.

[Plasma prekallikrein in chronic liver diseases]

Plasma prekallikrein (PPK) is a single-chain glycoprotein synthesized in the liver. The aim of our study was to evaluate a plasma prekallikrein as the marker reflecting liver protein synthesis in patients with chronic liver diseases. PPK levels have been measured by own modification of amidolytic micro-assay in 43 patients with chronic liver diseases and 37 healthy volunteers as control group. As compared to control group, PPK level was significantly decreased in patients with chronic active hepatitis and with decompensated liver cirrhosis and significantly increased in patients with liver cirrhosis complicated by hepatocellular carcinoma. There was no difference in plasma prekallikrein between patients with compensated liver cirrhosis and controls. The results suggest that PPK might be a useful index for the assessment of residual functional liver mass in patients with chronic liver diseases.

Synthesis of novel, aminoalkanolic derivatives of 5,7-dihydroxy-2-phenylbenzopyran-4-on as the potential cytostatic agents

The 7-(2,3-epoxypropoxy)-2-phenyl-5-hydroxy-4H-benzopyran-4-on and its aminoalkanolic derivatives were prepared as the potential cytostatic (antileukemic) compounds. They were tested in vivo on mice leukemia L1210.

[Elevated plasma prekallikrein level in patients with diabetes]

The contact activation of intrinsic pathway in the coagulation system accompanied by plasma kallikrein-induced kinin generation is thought to be involved in the pathogenesis of diabetic retinopathy. Plasma prekallikrein (PPK), a proenzyme of plasma kallikrein, is a single-chain glycoprotein synthesized mainly in the liver. The aim of our study was to evaluate plasma prekallikrein level in diabetic patients and to examine the relationship between PPK and the metabolic control of diabetes and development of retinopathy. In 53 diabetic patients and 33 healthy subjects as controls the following parameters have been assessed: plasma prekallikrein, serum fructosamine, glycated haemoglobin HbA1c, prothrombin time, partial thromboplastin time and antithrombin III (AT III). Compared to the control group, PPK level was significantly higher in diabetics, especially in patients with proliferative retinopathy. The significant positive correlations have been found between PPK and HbA1c in diabetic patients and between PPK and serum fructosamine concentration but only in diabetics without retinopathy. No differences in prothrombin time and AT III have been observed between diabetics and healthy subjects. A suggestion is presented on increase of plasma prekallikrein level in diabetics due to hyperglycaemia-stimulated glycoprotein over-synthesis in the liver, what would confirm the role of kallikrein-kinin system in the pathogenesis of microangiopathy.

Plasma prekallikrein levels in patients with hepatocellular carcinoma and liver cirrhosis: a pilot study

The concentration of plasma prekallikrein (PK) in five patients with hepatocellular carcinoma (HCC) has been measured and related to levels in 18 patients with liver cirrhosis (LC) and 30 healthy subjects. It was found that the mean PK level was significantly increased in patients with HCC, while patients with LC demonstrated lower concentrations, as compared with healthy subjects. The results indicate that PK might be useful in screening cirrhotic patients for HCC. Longitudinal studies of PK in a larger group of patients at risk of developing HCC are therefore recommended.

Early induction of immune resistance against leukemia in mice after lethal irradiation followed by syngeneic bone marrow transplantation and injection of syngeneic leukocytes

BALB/cxDBA/2Wf F1 (CD2F1) mice were lethally irradiated and reconstituted with syngeneic bone marrow cells untreated or treated with 75 micrograms/ml of mafosfamide. One day after bone marrow transplantation some groups of mice were injected with syngeneic splenocytes, peripheral blood leukocytes, or thymocytes. Seven days after marrow grafting the anti-L1210 leukemia immunization of mice, consisting of four i.p. injections of 10(6) L1210-Maf cells (L1210 cells treated in vitro with mafosfamide for inhibition of their growth in vivo), was started. Strong resistance against leukemia could be obtained only in mice receiving splenocytes or peripheral blood leukocytes, not in mice injected with thymocytes or in those not receiving any cells. In vitro elimination of various subpopulations from among the splenocytes before their injection into the mice made it possible to deduce which are necessary for early induction of antitumor resistance after bone marrow transplantation in mice. These cells are: Thy 1.2-, Ig-, AsGM 1-, Mac 1+, 1-Ad+/-, are adherent and nonsusceptible to carrageenan toxicity.

Return of immunohematopoietic impairment a long time after murine syngeneic bone marrow transplantation

We have tested the immunologic status and hematologic parameters of mice 2 months (short-term survivors) or 18 months (long-term survivors) after lethal total body irradiation and syngeneic bone marrow transplantation (SBMT), and of normal mice of corresponding age. Long-term SBMT survivors showed significantly lowered bone marrow and spleen cellularities, decreased numbers of CFU-S in hemopoietic organs and severe impairment in the formation of CFU-F colonies compared with short-term SBMT survivors and normal mice. The peripheral blood parameters (hematocrit, erythrocytes, reticulocytes, platelets, white blood cells and granulocyte counts), however, remained unaltered. In long-term SBMT survivors we also observed a relative increase of Lyt-2+ lymphocytes (CD8+, cytotoxic/suppressor) and Mac-1+ cells among splenocytes. At the same time the L3T4+/Lyt-2+ ratio (CD4+/CD8+) was decreased. Relative contents of Ig+, Thy-1+ and L3T4+ cells were unchanged. The ability of splenocytes to generate IL-2R+ cells after in vitro stimulation with concanavalin A was greatly diminished. In summary, the immunohematopoietic status after initial normalization is again impaired in long-term SBMT survivors.

Early induction of immune resistance against leukemia in lethally total body irradiated mice reconstituted with syngeneic bone marrow cells obtained from previously immunized donor mice

BALB/c x DBA/2 F1 (CD2F1) mice were lethally irradiated and reconstituted with syngeneic bone marrow cells (SBMC) obtained from normal or previously immunized (against L1210 lymphatic leukemia) donors. These recipient mice are called TBI + SBMT or TBI + Imm-SBMT mice, respectively. TBI + Imm-SBMT, but not TBI + SBMT mice, were able to develop strong immune resistance against L1210 leukemia, but not against MOPC 104E plasmacytoma, if the immunization procedure (four i.p. injections at weekly intervals of immunogenic L1210 cells) was started as early as 7 days posttransplantation. Incubation of Imm-SBMC with mafosfamide (ASTA Z7654) before grafting abrogated the ability of the recipient mice to develop early resistance against the leukemia. Treatment of Imm-SBMC with monoclonal or polyclonal antibodies plus complement showed that two or three subpopulations of Imm-SBMC were necessary for the transfer of immune information against leukemia: T lymphocytes with phenotype Thy 1.2+, Lyt 1+2-, I-Ad-, macrophages with phenotype Mac-1+, I-Ad-, and probably asialo-GM 1+ cells. Recipient mice immunized against L1210 leukemia before TBI + SBMT do not develop early resistance to the leukemia.

Successful adoptive immunotherapy of minimal residual disease after chemoradiotherapy and transplantation of bone marrow purged of leukaemia with mafosfamide

The effectiveness of adoptive immunotherapy in eliminating minimal residual disease in tumour-bearing mice after bone marrow transplantation was tested. This model mimics the human clinical condition when autologous bone marrow was purged ex vivo of leukaemia with mafosfamide or was not purged, and stored in liquid nitrogen before transplantation. Animals with minimal residual disease were prepared with marrow-ablative but leukaemia-noncurative doses of cyclophosphamide (CY) and total body irradiation followed by bone marrow transplantation. The next day after transplantation the recipients were injected with splenocytes immunized against the leukaemia cells (Imm-SPL) or monoclonal antibody (mAb). All the control mice died from leukaemia relapse, but 51% of purged bone marrow recipients, which received Imm-SPL, were cured. In similar conditions mAb did not exert a therapeutic effect. Imm-SPL were not able to eradicate minimal residual disease in the recipients of nonpurged bone marrow. Thus, in an animal model, we demonstrated that purging of bone marrow before grafting seems to be indispensable for successful adoptive immunotherapy of minimal residual disease (MRD) after autologous bone marrow transplantation.

The kinetics of immunologic and hematologic recovery in mice after lethal total body irradiation and reconstitution with syngeneic bone marrow cells treated or untreated with mafosfamide (ASTA Z 7654)

The immunohematopoietic reconstitution of mice lethally irradiated (TBI) and reconstituted with syngeneic bone marrow cells untreated or treated with mafosfamide (ASTA Z 7654) [TBI + SBMT or TBI + SBMT-Maf mice, respectively] was examined. The number of CFU-S was greatly reduced in TBI + SBMT-Maf mice compared with those in TBI + SBMT mice. The recovery of blood parameters (hematocrit, reticulocytes, erythrocytes, white blood cells, granulocytes, platelets) and of bone marrow and spleen cells, but not of peritoneal exudate cells, was slightly delayed in TBI + SBMT-Maf mice compared with those in TBI + SBMT mice. The time for immune system regeneration was, however, considerably longer in TBI + SBMT-Maf than in TBI + SBMT mice, as measured by the incidence of Ig+, Thy-1.2+, L3T4+, Lyt-2+, and IL-2R+ cells in the spleens. The appearance of Mac-1+ and asialo-GM 1+ cells was only slightly prolonged or unchanged, respectively.

Successful chemoimmunotherapy of murine L1210 lymphatic leukemia with cyclophosphamide and mafosfamide-treated leukemia cells

Balb/c x DBA/2 F1 mice (CD2F1 mice) bearing L1210 lymphatic (10 L1210 cells i.p. injected on day 0) were subjected to chemoimmunotherapy. They received 100 mg/kg of cyclophosphamide i.p. on day +8 and 10(6) or 10(7) immunogenic L1210 cells treated in vitro with mafosfamide - ASTA Z7654 (L1210-Maf cells) i.p. or i.p. + s.c. on days 0, +3, +6, +9, +12 after the leukemia implantation. About 30% of leukemia-bearing mice receiving cyclophosphamide and L1210-Maf cells after L1210 inoculation were able to reject the leukemia (as compared with 0% after injection of L1210-Maf cells only or 5% after cyclophosphamide administration). Better results (54% of cured mice) were obtained if 10(7) L1210-Maf cells were injected i.p. +s.c. beside cyclophosphamide. Biological response modifiers (BRM's): levamisole, BCG, bestatin did not improve these results in the doses used in the experiment. Augmentation of anti-L1210 therapeutic response is dependent on the administration of cyclophosphamide and L1210-Maf cels. Cyclophosphamide not only reduces the tumor burden but probably can potentiate the L1210-Maf dependent antitumor immunity as well.

Cytochemical characterization of mouse L1210 leukemia

Mouse lymphatic leukemia L1210 cells were characterized with polyclonal and monoclonal antibodies and lectins. The cells were found to have the phenotype IgG-, Thy-1.2-, Lyt-1-, Lyt-2-, asialo-GM1-, TL-, I-Ad-, IL-2R+, peanut agglutinin+, and Helix pomatia lectin +/-. They retained expression of H-2Kd and H-2Dd. Thus, these cells resemble "null" cells.

Mechanisms of immunological response induced in CD2F1 mice by administration of semisyngeneic L 1210 leukemia cells treated with cyclophosphamide

CD2F1 mice were immunized against semisyngeneic L 1210 leukemia. Immunization was achieved by four i.p. injections, in weekly intervals, of L 1210 cells treated in vivo twice with 200 mg/kg of cyclophosphamide. The immunized animals survived i.p. challenge with 1000 untreated L 1210 cells that was lethal for nonimmunized mice. The immunity could be abrogated in vivo with anti-mouse thymocyte serum, carrageenan or reserpine, but not by anti-mouse IgG serum, suggesting participation of T lymphocytes and macrophages in the response. Moreover, lymphocytes and macrophages from the peritoneal cavity of immunized mice were cytotoxic in vitro for L 1210 cells. The immunity, at least partially, could be adoptively transferred with peritoneal exudate cells or splenocytes.

Preparation and some properties of highly purified human serum kallikrein

A 3000--6000-fold purified kallikrein was obtained from human serum in 10--25% yield by chromatography on QAE-Sephadex A-50, Molselect CM-50 and on soybean trypsin inhibitor (SBTI)-AH-Sepharose 4-B. The enzyme had a specific activity of 14--23 U, as measured by BAEE hydrolysis. Some properties of highly purified kallikrein are described.

Preparation and some properties of human serum kallikrein immobilized on ARM-Sepharose

A highly purified human serum kallikrein immobilized on CH-Sepharose 4-B was obtained. KM values for N-benzoyl-L-arginine ethyl ester and N-tosyl-L-arginine methyl ester hydrolysis of this preparation were 1.10 x 10(-3) M and 3.6 x 10(-4) M, respectively; pH optimum of hydrolysis of these esters were found to be 8.2 and 8.5, respectively. The immobilized kallikrein possessed kininogenase activity and was capable of activating prekallikrein.