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An intermolecular nickel-catalyzed reductive 1,2-alkylarylation of acrylates with cyclopropylamine NHP esters and aryl iodides is reported. This operationally simple protocol provides direct access to 1-alkylcyclopropylamine scaffolds. The mild conditions are compatible with four-membered α-amino strained rings as well as five- and six-membered ring systems. The products undergo cyclization to access α-arylated spirocyclic γ-lactams─a motif present in several pharmaceuticals.

Despite the importance of heteroatom-substituted cyclopropane derivatives in drug design and organic synthesis, cyclopropanethiols remain critically underexplored. Inspired by the wide use of the Newman-Kwart rearrangement to access valuable thiophenols from phenol feedstocks, we report the development of a photocatalytic approach for efficient ambient temperature aliphatic O- to S-rearrangement on tertiary cyclopropanol derivatives. After demonstrating that a range of cyclopropanethiols-that are difficult to access by other methods-can be obtained with this strategy, we show that these rearranged products can be easily hydrolyzed and further derivatized. We conclude this study with mechanistic findings that enabled an initial extension of this approach toward other classes of aliphatic alcohols., (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Modelling of many real-world processes, such as drug delivery, wastewater treatment, and pharmaceutical production, requires accurate descriptions of the dynamics of hard particles confined in complicated domains. In particular, when modelling sedimentation processes or systems with driven flows, it is important to accurately capture volume exclusion effects. This work applies Dynamic Density Functional Theory to the evolution of a particle density under diffusion, external forces, particle-particle interaction, and volume exclusion. Using a spectral element framework, for the first time it is possible to include all of these effects in dynamic simulations on complex domains. Moreover, this allows one to apply complicated no-flux, and other non-local, non-linear, boundary conditions. The methodology is also extended to control problems, addressing questions of how to enhance production set-up in industrially-motivated processes. In this work the relevant models are introduced, numerical methods are discussed, and several example problems are solved to demonstrate the methods' versatility. It is shown that incorporating volume exclusion is crucial for simulation accuracy and we illustrate that the choice of boundary conditions significantly impacts the dynamics., (© 2023 Author(s). Published under an exclusive license by AIP Publishing.)

This paper is concerned with the implementation of efficient solution algorithms for elliptic problems with constraints. We establish theory which shows that including a simple scaling within well-established block diagonal preconditioners for Stokes problems can result in significantly faster convergence when applying the preconditioned MINRES method. The codes used in the numerical studies are available online.

Interior point methods provide an attractive class of approaches for solving linear, quadratic and nonlinear programming problems, due to their excellent efficiency and wide applicability. In this paper, we consider PDE-constrained optimization problems with bound constraints on the state and control variables, and their representation on the discrete level as quadratic programming problems. To tackle complex problems and achieve high accuracy in the solution, one is required to solve matrix systems of huge scale resulting from Newton iteration, and hence fast and robust methods for these systems are required. We present preconditioned iterative techniques for solving a number of these problems using Krylov subspace methods, considering in what circumstances one may predict rapid convergence of the solvers in theory, as well as the solutions observed from practical computations.

Background: Onconase, a protein isolated from oocytes and early embryos of the frog Rana pipiens, shares extensive homology with bovine pancreatic ribonuclease (RNase A) and possesses similar enzyme activity. Onconase is cytotoxic toward cancer cells in vitro and exhibits antitumor activity in animal models. In addition, Onconase has been shown to enhance the cytotoxic activity of some chemotherapeutic agents in vitro., Purpose: We studied interactions between the cytotoxic effects of Onconase and the chemotherapeutic agent vincristine (VCR) in the treatment of drug-sensitive and multidrug-resistant human colon carcinoma cells in vitro and in mice., Methods: Transplantable human colon carcinoma cells (HT-29par cells) were infected with a retrovirus containing human mdr1 (also known as MDR1 and PGY1) complementary DNA (encoding P-glycoprotein [P-gp]), and clones that were cross-resistant to colchicine, doxorubicin, and vinblastine were selected (HT-29mdr1 cells). Drug-resistant HT-29mdr1 cells and drug-sensitive HT-29par parental cells were treated with Onconase and/or VCR in vitro at varying concentrations to measure the effects on protein synthesis and cell viability. The impact of Onconase on VCR accumulation in both types of cells was determined in the presence or absence of MRK-16, an anti-P-gp monoclonal antibody capable of reversing the multidrug-resistant phenotype. The antitumor effects of Onconase and/or VCR treatment were assessed in nude mice bearing established HT-29par or HT-29mdr1 intraperitoneal tumors. IC50 values (drug concentrations resulting in 50% inhibition of protein synthesis or cell viability) for Onconase and VCR were determined from semilogarithmic dose-response curves; interactions between the cytotoxic effects of these two agents were evaluated using data from protein synthesis inhibition experiments and a two-way analysis of variance. Survival distributions from in vivo experiments were compared using Cox proportional hazards models., Results: The combination of Onconase and VCR yielded enhanced cytotoxicity in vitro that was independent of P-gp expression. Evaluation of the effects of these two compounds on protein synthesis over a wide range of drug concentrations indicated possible synergistic interactions (i.e., greater than additive effects) in both drug-resistant and drug-sensitive cells. The enhancement of VCR cytotoxicity was dependent on Onconase enzyme activity and was not associated with increased intracellular levels of VCR. Simultaneous treatment of mice bearing HT-29par tumors with Onconase and VCR did not extend their median survival time (MST) significantly (MST with VCR = 66 days; MST with VCR plus Onconase = 69 days; two-tailed P = .57); however, the MST of mice with HT-29mdr1 tumors was extended significantly by this treatment (MST with VCR = 44 days; MST with VCR plus Onconase = 66 days; two-tailed P<.001)., Conclusion: Combined administration of Onconase and VCR yields enhanced cytotoxicity in vitro and in vivo against human colon carcinoma cells that overexpress the mdr1 gene.

Background: Colorectal cancer is a major cause of cancer-related mortality in the world and the second leading cause of neoplastic death in the United States. A major obstacle in the chemotherapy of this neoplasm is the emergence of multidrug resistance that is frequently associated with the expression of P-glycoprotein (p170) encoded by MDR1 (also known as PGY1) genes. Previously, we demonstrated that liposome-encapsulated doxorubicin is more cytotoxic than free doxorubicin in human promyelocytic leukemia and human breast cancer cells with the multidrug-resistant phenotype., Purpose: Our purpose was to investigate modulation of multidrug resistance by liposome-encapsulated vincristine (VCR) in a drug-resistant human colon cancer cell line HT-29mdr1 and the potentiation of this modulation in combination with monoclonal antibody MRK-16 or verapamil., Methods: HT-29 parental cells and HT-29mdr1 cells were exposed to free VCR or liposome-encapsulated VCR alone or in combination with MRK-16 or verapamil. Cytotoxicity of cells after various treatments was determined by neutral red staining, and cellular content of VCR was measured by using radiolabeled VCR; p170 expression of cells was assessed by azidopine., Results: HT-29mdr1 cells express a high amount of p170, thus conferring sixfold to sevenfold resistance to VCR compared with the parent cell line. Liposome-encapsulated VCR lowers drug resistance in HT-29mdr1 cells fourfold; IC50 values (concentration that causes 50% reduction in cell number) were 12.5 +/- 2.5 ng/mL compared with 42.5 +/- 5.0 ng/mL with free VCR. IC50 values for free VCR with empty liposomes were 25 +/- 1.25 ng/mL. The combination of MRK-16 and free VCR produced a twofold increase in cytotoxicity over free VCR in p170-expressing cells; the combination of MRK-16 and liposome-encapsulated VCR produced a 10-fold potentiation of cytotoxicity. toxicity. Nonspecific monoclonal antibody NR-LU-10 had no effect on cytotoxicity of HT-29mdr1 cells with free VCR or liposome-encapsulated VCR. The combination of 1.5 microM verapamil potentiated the cytotoxicity of free VCR ninefold to 10-fold, IC50 values reduced to 5.0 +/- 1.5 ng/mL, and in combination with liposome-encapsulated VCR, IC50 values reduced to 2.5 +/- 1.0 ng/mL, demonstrating a 15- to 17-fold potentiation of cytotoxicity. There were no significant differences in drug accumulation in HT-29mdr1 cells when treated with liposome-encapsulated VCR or free VCR. Liposomes inhibited the photoaffinity labeling of azidopine to p170 HT-29mdr1 cells., Conclusions: Liposome encapsulation of VCR effectively modulates multidrug resistance in human colon cancer cells and may become an important modality in treatment for colon cancers.

Background: The anti-P-glycoprotein monoclonal antibody MRK-16 mediates the reversal of multidrug resistance. Recombinant human interferon alfa (rHuIFN alpha) enhances the cytotoxic activity of diverse chemotherapeutics and may modulate multidrug resistance., Purpose: Our purpose was to determine the outcome of combination treatment with MRK-16, rHuIFN alpha-2a, and cytotoxic agents on tumor cells that express P-glycoprotein (Pgp)., Methods: Three Pgp-expressing, multidrug-resistant human tumor cell lines were used: the MDR1 retrovirus-infected HT-29 colon adenocarcinoma (HT-29mdr1), the doxorubicin (Adriamycin)-resistant MCF-7 (AdrR MCF-7) breast carcinoma, and the de novo Pgp-acquired, HCT-15 colon carcinoma. The parental cell lines HT-29par and MCF-7 were used as controls. The in vitro effects of MRK-16 and rHuIFN alpha-2a were studied on: (a) chemosensitivity of parental and multidrug-resistant cell lines to vincristine, doxorubicin, or paclitaxel (Taxol); (b) intracellular drug concentrations; and (c) Pgp expression. The efficacy of vincristine alone or in combination with MRK-16 and/or rHuIFN alpha-2a was assessed against HT-29mdr1 cells in female, athymic NCr-nu/nu mice., Results: For vincristine, the IC50 (i.e., the concentration that causes 50% inhibition of cell growth) was 7.0 ng/mL in HT-29mdr1 cells. Pretreatment of HT-29mdr1 cells with MRK-16 partially restored vincristine sensitivity (IC50 = 4.8 ng/mL), which was enhanced by noncytotoxic concentrations of rHuIFN alpha-2a (IC50 = 2.9 ng/mL) via a mechanism independent of Pgp modulation or [3H]vincristine efflux. rHuIFN alpha-2a potentiated MRK-16 reversal of multidrug resistance with both doxorubicin and paclitaxel on HT-29mdr1 cells and with vincristine on AdrR MCF-7 and HCT-15 tumor cells. Treatment of mice with 1 mg/kg vincristine weekly for 3 weeks, beginning 10 days after tumor injection, significantly increased the median survival times of the HT-29par tumor-bearing mice (60 days versus 35 days; P < .0001) but was only marginally therapeutic for HT-29mdr1 tumor-bearing mice (52 days versus 46 days). Pretreatment with MRK-16 (500 micrograms) and rHuIFN alpha-2a (5 x 10(4) U), alone or in combination, 24 hours before vincristine therapy did not affect the survival of HT-29par tumor-bearing mice. In contrast, the survival of mice bearing HT-29mdr1 tumors was significantly increased following treatment with MRK-16 before vincristine (80 days; P < .0001). Administration of a nontherapeutic dose of rHuIFN alpha-2a (5 x 10(4) U) with MRK-16 before vincristine treatment further increased the median survival times of HT-29mdr1 tumor-bearing mice (116 days; P < .0001)., Conclusions: MRK-16 used in combination with rHuIFN alpha-2a was significantly more effective than MRK-16 in overcoming multidrug resistance.

We examined the expression of the estrogen and epidermal growth factor (EGF) receptors in a drug-resistant subline of MCF-7 cells in order to study potential alterations in hormone dependence or in the growth factor pathway that could be related to the development of drug resistance in human breast cancer. The drug-resistant subline was derived from MCF-7 cells by selection with Adriamycin in the presence of the P-glycoprotein antagonist, verapamil, to prevent acquisition of the classical multidrug resistance phenotype. The Adriamycin-resistant cells retain estrogen-binding, estrogen-responsive monolayer growth, and estrogen-dependent tumorigenesis. Estrogen-binding studies demonstrate 1.4 x 10(6) sites per cell with unaltered affinity when compared to parental MCF-7 cells, which have 2.7 x 10(5) sites per cell. An increase in expression of EGF receptor, eight to 12-fold, occurred early in the selection for drug resistance, and appears to be unrelated to verapamil exposure, since cells maintained in Adriamycin without verapamil also have increased EGF receptor expression. Partially drug-sensitive revertants carried a verapamil, but out of Adriamycin, demonstrate a decline in EGF receptor expression. We postulate that activation of growth factor pathways in drug-resistant cells may enhance mechanisms of drug resistance, or provide mitogenic stimuli for cells to recover after damage by drug exposure.

Background: We have demonstrated that, in the human ovarian carcinoma cell line (OVCAR-3), recombinant human interferon alpha (rHuIFN-alpha) potentiated in vitro inhibition of protein synthesis by immunotoxins. The antitumor activity of intracavitary immunotoxin administered to nude mice 5 days after tumor cell injection was enhanced by a nontherapeutic dose of rHuIFN-alpha, as evidenced by increased survival time., Purpose: Our purpose was to determine the outcome of treatment with immunotoxin and rHuIFN-alpha in xenografts of more advanced tumors., Methods: At 10 or 15 days after tumor cell injection, nude mice with peritoneal OVCAR-3 xenografts were treated intraperitoneally with immunotoxin or with 454A12 monoclonal antibody (MAb) recombinant ricin A chain (rRA), alone or combined with a nontherapeutic dose of rHuIFN-alpha. The immunotoxin was composed of rRA covalently bound to an anti-CD71 (transferrin receptor) MAb. In other experiments, mice were treated intraperitoneally with cyclophosphamide and cisplatin to reduce tumor size on days 20 and 27 after tumor cell inoculation and then, beginning on day 40, with immunotoxin alone or combined with rHuIFN-alpha., Results: Initiation of treatment 10 days after OVCAR-3 transplantation significantly increased median survival from 41 to 89 days (10% survivors on day 120) with 454A12 MAb rRA alone and to more than 120 days (70% survivors) with 454A12 MAb rRA combined with rHuIFN-alpha (P < .0001). The increase in survival time between tumor-bearing mice treated with immunotoxin combined with rHuIFN-alpha and those treated with immunotoxin alone was statistically significant (P = .017). In contrast, the 15-day transplant tumors were not curable with immunotoxin therapy (survival, 72 days; 0% survivors) and were refractory to rHuIFN-alpha potentiation (survival, 75 days; 0% survivors). After the second course of chemotherapy to reduce the size of the advanced tumors (day 40), during the ascites cell count nadir, initiation of treatment with 454A12 MAb rRA alone or combined with rHuIFN-alpha resulted in significantly different survival times of 129 and 162 days, respectively (P = .0037). Pathologic examination of surviving mice treated with chemotherapy and 454A12 MAb rRA alone or in combination with rHuIFN-alpha revealed that one (17%) of six mice and 11 (65%) of 17 were tumor free, respectively., Conclusions: The synergy between immunotoxins and IFN-alpha is dependent on tumor burden. These agents are less effective against large tumor burdens (i.e., advanced stage disease), but their beneficial effects re-emerge after cytoreduction by combination chemotherapy., Implications: The ideal setting for testing the efficacy of intracavitary immunotoxin combined with rHuIFN-alpha after front-line chemotherapy is in patients with residual tumor refractory to additional chemotherapy or in those with toxic effects that prevent delivery of effective doses.

We have examined the ability of bryostatin 1 to inhibit the in vitro growth and in vivo development of a panel of four murine tumors of diverse tissue origins. A wide range of antiproliferative responses was observed for the four tumors. At 100 ng/ml the in vitro growth of the Renca renal adenocarcinoma, the B16 melanoma, the M5076 reticulum cell sarcoma, and the L10A B-cell lymphoma were inhibited by 0, 40, 40, and 94% respectively. All three cell lines sensitive to bryostatin in vitro responded to multiple dose, 1 microgram/injection/day in vivo i.p., bryostatin therapy. Only the in vitro resistant Renca tumor failed to respond to bryostatin in vivo. The correlation between in vitro and in vivo antitumor efficacy suggests a direct mechanism of antitumor activity for bryostatin. Both local regional therapy (M5076 i.p.) and systemic therapy (B16 lung metastases and L10A s.c. tumors) with bryostatin were successful at prolonging survival time. Multiple i.p. doses of bryostatin at a minimum level of 0.5-1.0 microgram/injection were required to observe significant in vivo antitumor effects. The success of in vivo administration of bryostatin in mice bearing 8-10-mm s.c. masses of L10A lymphoma (5-10 x 10(9)) and our further observation that five of a panel of six human B-cell lymphoma cell lines were sensitive to the growth inhibitory effects of bryostatin in vitro suggest that bryostatin may be effective in treating lymphoid malignancies in humans.

One strategy to overcome multidrug resistance in neoplasia is to inhibit the gp170 glycoprotein (relative molecular mass, 170,000) that functions as a plasma membrane, energy-dependent, drug-efflux pump. The human colon cancer cell line HT-29, which grows as an ascitic tumor in athymic NCr-nu/nu nude mice, was made multidrug resistant by infection with an MDR1 (also known as PGY1) retrovirus. Referred to as HT-29mdr1, it was used to study reversal of drug resistance in vivo by the anti-P-glycoprotein monoclonal antibody MRK-16. Flow cytometry and radioimmunoassay demonstrated a marked increase in MRK-16 reactivity on HT-29mdr1 cells as compared with its reactivity on the parental, uninfected cell line (HT-29par). The 50% inhibitory concentrations (IC50) of vincristine on HT-29par and HT-29mdr1 cells were 2.5 and 15 ng/mL, respectively. The MRK-16 monoclonal antibody did not affect the vincristine sensitivity of the HT-29par cells. Pretreatment of HT-29mdr1 cells with 10 micrograms/mL MRK-16 in tissue culture partially restored the vincristine sensitivity (IC50 = 7 ng/mL). This modulation of vincristine sensitivity by MRK-16 was then tested in vivo. The median survival times of mice given intraperitoneal transplants of 5 x 10(6) HT-29par or HT-29mdr1 were 37 and 39 days, respectively. Treatment of mice with 1 mg/kg vincristine weekly for 3 weeks, beginning 10 days after tumor injection, resulted in a significant increase in the median survival time of the HT-29par tumor-bearing mice (68 days, P less than .0001), but it had no effect on the HT-29mdr1 tumor-bearing mice. However, treatment of mice bearing the HT-29mdr1 tumor with MRK-16 before vincristine therapy reversed the resistance to the drug (median survival time = 64 days, P less than .0001). The MRK-16 monoclonal antibody alone had no effect on the median survival time of mice given an injection of either HT-29par or HT-29mdr1 cells. These results suggest that strategies employing monoclonal antibody against gp170 may be clinically useful to reverse multidrug resistance.

Immunotoxins of PE were constructed with stable thioether linkages using two monoclonal antibodies to ovarian cancer, OVB-3 and NR-LU-10. Antigens recognized by both antibodies have limited normal tissue distribution and are expressed on virtually all ovarian cancers. Both antibodies form highly potent conjugates (ID50 = 100 pg/ml) with high selectivity (greater than or equal to 4 logs) and can eliminate greater than or equal to 5 logs of tumor cells in vitro. The conjugates have been evaluated for efficacy in both ovarian and colon carcinoma ascites xenografts. In the ovarian model, the conjugates produce an increase in life span (ILS) of 200 to 300 with some cures against established but low tumor burden ascites. Increasing the tumor burden decreases efficacy and duration of responses. A lower ILS of 150 to 200 is achieved in the more aggressive colon model. However, the combination of immunotoxin with chemotherapy, which is ineffective on its own, demonstrated enhanced activity (ILS = 300). Toxicity of the conjugates is hepatic and easily monitored by liver function tests (LDH). Antitoxin responses are highly variable, but typically have a rapid onset and appear to be predicted by preexisting levels. Pilot clinical evaluation in ovarian cancer (intraperitoneal) is ongoing.

The antitumor effects of two immunotoxins were evaluated in vitro and in vivo against the human ovarian carcinoma cell line, OVCAR-3. The immunotoxins used were composed of recombinant ricin A chain (rRTA) covalently attached to a monoclonal antibody directed toward the human transferrin receptor (45412/rRTA, also called 454A12 MAB-rRTA by Cetus Corporation) or Pseudomonas exotoxin coupled to an anticarcinoma monoclonal antibody (NR-LU-10/PE). Preliminary characterization of the NR-LU-10 antigen by immunoprecipitation and cellular fluorescence demonstrated two dominant cell surface polypeptide moieties with molecular weights of 40,000 and 45,000 and a minor component with a molecular weight of 33,000. The immunotoxins were used alone or in combination with recombinant human alpha-interferon (rhIFN-alpha). Protein synthesis was inhibited in a dose-dependent manner in OVCA-3 cells incubated in vitro with either NR-LU-10/PE or 454A12/rRTA (50% inhibitory concentrations, 1 and 75 ng/ml, respectively). Unconjugated NR-LU-10 or 454A12 abrogated the activity of the relevant immunotoxins. Concomitant incubation in vitro of OVCAR-3 cells with NR-LU-10/PE or 454A12/rRTA and a noncytotoxic concentration of rhIFN-alpha potentiated the inhibitory activity of the immunotoxins via a mechanism independent of antigenic upregulation. This potentially synergistic combination was then tested in vivo. The median survival time (MST) of mice given injections i.p. of 4 x 10(6) OVCAR-3 cells was 46 days. Cohorts of mice that received intracavitary treatment beginning 5 days posttumor cell inoculation with either 0.25 or 0.5 microgram of NR-LU-10/PE every other day for a total of 10 treatments exhibited a significantly increased MST of 63 and 104 days, respectively (P less than 0.0001). Likewise, the i.p. injection of either 2.5 or 10 micrograms of 454A12/rRTA given in an identical schedule resulted in a MST of 89 and greater than 120 days, respectively (P less than 0.0001). When rhIFN-alpha was administered i.p. in conjunction with those doses of either immunotoxin, a significant increase in the MST was observed in comparison with mice given immunotoxin alone. The combination of 5 x 10(4) units of rhIFN-alpha and 0.25 microgram of NR-LU-10/PE resulted in 67% long-term survivors (greater than 120 days) compared with only 13% survival of mice given the immunotoxin alone. Similarly, 2.5 micrograms of 454A12/rRTA plus rhIFN-alpha resulted in an enhanced therapeutic response (89% long-term survivors) when compared with 454A12/rRTA alone (29%).(ABSTRACT TRUNCATED AT 400 WORDS)

Fischer F 344/CRBL female rats were injected intravenously with 10(6) syngeneic 13,762 adenocarcinoma cells, and daily doses of either 10 micrograms, 100 micrograms or 1 mg Staphylococcus aureus protein A were administered intraperitoneally on days 1 through 11. The animals were sacrificed on day 12, their lungs infused with Bouin's solution, and lung metastases counted. A significant reduction in the number of visible metastatic nodules was observed in the animals given 100 micrograms and 1 mg of Staphylococcus aureus protein A daily.

Staphylococcus aureus protein A (SPA) acts as a mitogen stimulating DNA synthesis and is not antagonistic to the mitogenic activity of other mitogens. The mitogenicity of SPA is due to the protein's multivalent Fc antibody receptors. Partial trypsin digestion of SPA yields monovalent Fc antibody receptors which are not mitogenic. Using a thymidine incorporation assay, results indicated that tryptic digests of SPA added to mouse splenic leukocytes 12 hours after stimulation with either concanavalin A, lipopolysaccaride or SPA suppressed the DNA synthesis normally elicited by these mitogens. SPA was digested with 1% trypsin at pH 8 for varying periods of time. As the digestion time increased from 0 to 60 minutes the mitogenicity of the SPA-trypsin digests decreased indicating cleavage from multivalent to monovalent SPA Fc antibody receptors. The decrease in mitogenicity of the SPA digests was directly associated with increased ability to inhibit DNA synthesis in mitogen stimulated leukocytes. A proposed mechanism for the inhibition of DNA synthesis suggests that SPA-monovalent Fc antibody receptors mimic cellular Fc receptor function thereby influencing cellular gene expression.

The effects of six clinically active drugs were tested against a ttansplantable leukemia in inbred strain 2 guinea pigs. Cytoxan and 6-mercaptopurine were found to elicit a therqeutic response against this leukemia based on complete tumor regression of the established tumor as well as a substantial increase in survival time. Animals dying in the untreated control and drug-treated groups revealed typical generalized lymphoblastic leukemia. However, only Cytoxan-treated animals that had relapsed exhibited central nervous system involvement originating from the arachnoid membrane. A tow-drug combination of Cytoxan and 1-(2-chloroethyl)-3(trans-4-methylcyclohexyl)-1-nitrosourea was found not only to prevent meningeal leukemia development but also to result in "curing" all animals from their leukemia. This observation was based on a complete clinical, hematological, and histopathological "remission" period up to 176 days. The administration of 1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea alone was observed not only to control the systemic leukemia but also to prevent central nervous system involvement. No relapses occurred after the first "remission" period was achieved in the groups of animals that received 1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea.

Presented is an analysis of experience from July, 1973, through June, 1982, in a teaching institution that served a high-risk urban population. The suggestion is made that improvement in perinatal mortality does not necessarily rely upon an ever-increasing cesarean section rate. During the 9 years encompassed by the study, the total cesarean section rate ranged from a low of 5.8% to a high of 8.2%. The primary cesarean section rate was first recorded separately in 1976, and stayed between 3.2% and 4.9%. During the same span of time, the uncorrected Perinatal Group II mortality rate dropped from 35/1,000 to 18/1,000. An attempt is made to interpret the various factors involved in accomplishing these results.

Treatment of normal BALB/c mice with nystatin, an amphoteric polyene, activated macrophages to become tumoricidal for MBL-2 lymphoblastic leukemia target cells while augmenting the in vitro blastogenic response of splenic lymphocytes to B and T cell mitogens. These responses were both shown to be highly dose dependent and occurred 6 days following the intraperitoneal injection of nystatin into normal mice. Macrophages from untreated mice did not show similar activity. The significance of these observations and the potential use of nystatin as a pharmacologic agent is discussed.

A distinct clinical syndrome of severe buttock pain radiating down the posterior surface of the ipsilateral leg and subsequent inability to ambulate has recently been recognized. The syndrome may develop in the parturient following a paracervical block. This study analyzes 4 cases from the authors' institution and reviews 2 cases from the literature. Onset of the syndrome ranges from 12 hours to 10 days but progressive improvement and complete recovery are the rule. The cause is believed to be secondary to direct trauma or hematoma formation in the area of the sacral plexus. Pelvic induration or a mass in the sacroiliac area may be noted bur abscess formation is not associated. Prevention is difficult but early recognition will facilitate treatment, which is mostly symptomatic.

The development of successful approaches to immunotherapy is dependent on the proper consideration of the pathobiology of metastasis and a better understanding of the principles of biological response modification. Immunomodulation as a therapeutic modality has not proven notably effective in animals with preexistent palpable disease, an observation in agreement with the results from clinical protocols. Therefore, rather than developing experimental immunotherapy models of immunoprophylaxis or models with minimal tumor burden, we believe it more appropriate to develop models based on preexistent metastatic disease in a tumor-conditioned host. The most rigorous test of a biological response modifier's efficiency prior to clinical trials will be provided from immunotherapeutic trials of palpable autochthonous tumors.

A mouse IgG2b anti-pan carcinoma monoclonal antibody, NR-LU-10, was shown to bind homogeneously to ascites xenografts of both ovarian and colon carcinoma. Following linkage to a highly potent holotoxin, Pseudomonas exotoxin A (PE), NR-LU-10 demonstrated high potency and selectivity in vitro (ID50 = 100 pg/ml; elimination of greater than or equal to 4.5 logs of cells). The conjugate was evaluated for therapeutic efficacy against a human colon tumor (HT-29) transplantable in the peritoneal cavity of nude mice. Beginning 3 days after HT-29 injection, mice received either three or six i.p. injections of 0.5 micrograms of unconjugated NR-LU-10 or immunotoxin conjugate (NR-LU-10/PE) every other day. Mice that received three or six treatments of NR-LU-10 alone had median survival times (MSTs) of 39 and 40 days, respectively, which did not differ significantly from the MST observed for the untreated control groups (MST = 35 days). In contrast, treatment with three or six injections of 0.5 micrograms NR-LU-10/PE exhibited significantly increased MSTs (P = 0.002) of 50 and 60 days, respectively. Coinjection of unconjugated NR-LU-10 (20 micrograms) and 0.5 micrograms of NR-LU-10/PE blocked the therapeutic effect of the immunotoxin (MST = 33 days). The therapeutic efficacy of NR-LU-10/PE was further enhanced against HT-29 when administered i.p. during and after cytoreductive chemotherapy. The i.p. administration of 300 mg/lg of cyclophosphamide plus 100 mg/kg of the chemoprotective drug, WR-2721, 10 and 17 days posttumor cell inoculation induced a significant increase in MST from 36 days to 59 days (P = 0.002). Interestingly, groups of mice that received either two, four, or seven treatments of NR-LU-10/PE following cytoreductive therapy exhibited a further significant increase (P = 0.001) in MSTs of 89, 97, and 105 days, respectively. Therefore, the use of immunotoxin therapy following cytoreductive chemotherapy significantly prolonged survival time of mice bearing the HT-29 colon tumor over that observed with chemotherapy or NR-LU-10/PE alone.

The efficacy of intracavitary chemoimmunotoxin therapy for cancer treatment was evaluated using the human colon carcinoma (HT-29) which had been xenografted i.p. into nude mice. Mice bearing HT-29 were treated with an immunotoxin consisting of the monoclonal antibody OVB3 coupled to Pseudomonas exotoxin (OVB3-PE), with cyclophosphamide (Cy), or with both OVB3-PE plus Cy. Mice given injections i.p. of 3 x 10(6) HT-29 ascites cells developed a localized disease that presented as both malignant ascites and solid tumor confined to the peritoneal cavity. All mice died within 30 to 40 days. Mice that received either three or six injections of OVB3-PE at a dose of 0.5 micrograms every other day beginning 3 days post-tumor inoculation exhibited significantly increased median survival times (MSTs) (P = 0.002) of 62 and 68 days, respectively, as compared to a MST of 33 days for the controls. OVB3 alone or an irrelevant monoclonal antibody conjugated to PE exhibited no antitumor activity. The therapeutic effects of the immunotoxin could be blocked by giving a large amount of unconjugated OVB3 at the same time. Treatment of mice with Cy alone at the maximal tolerated dose (250 mg/kg) on Days 10 and 17 after tumor inoculation increased the MST from 33 days to 54 days. The maximum tolerated dose could be increased to 300 mg/kg per injection if the Cy treatment was preceded by 100 mg/kg of S-2-(3-aminopropylamino)ethyl phosphorothioic acid (WR-2721), a sulfhydryl compound that selectively protects normal tissue against the toxicity of radiation and alkylating agents. Cy plus WR-2721 treatment on Days 10 and 17 increased the MST from 35 to 61 days (P = 0.002). Interestingly, groups of mice that received either two, four, or seven treatments of OVB3-PE following Cy plus WR-2721 therapy exhibited a further increase (P less than 0.002) in MSTs to 81, 87, and 96 days, respectively. Thus, the combination of cytoreductive chemotherapy with the OVB3-PE was significantly more effective for the intracavitary treatment of established HT-29 colon cancer xenografts than either chemotherapy or immunotoxin therapy alone.

Staphylococcus-aureus protein A (SPA) incubated with sera containing immune complexes and effector cells increases antibody dependent cellular cytotoxicity (ADCC)and rosette formation. The enhanced ADCC and rosetting is due to SPA functioning as an IgG Fc cellular receptor. SPA binds to the Fc portion of Igg and has much greater affinity for immune complexes than free IgG. SPA bound immune complexes are blocked from attaching to the Fc cellular receptors via a competitive inhibition which neutralizes the inhibitory effect of these complexes on ADCC and rosette formation.

Gelonin, a ribosome-inactivating protein from the seeds of Gelonium multiflorum, has been conjugated to antibodies. Previous reports have indicated variable potency of such immunotoxins. The lack of toxicity of gelonin, however, makes it attractive for immunoconjugate production. The ribosome-inactivating protein was covalently linked (using N-succinimidyl-3-(2-pyridyldithio)propionate) to monoclonal antibody, 9.2.27, directed to a human melanoma-associated glycoprotein/proteoglycan. The immunoconjugate showed high selectivity with dose-dependent cytotoxic activity to cultured human melanoma cells (50% inhibitory dose; 1-3 X 10(-11) M versus antigen-positive cells; 1-3 X 10(-7) M versus antigen-negative cells). Specificity and immunoreactivity of the conjugate were similar to those of unconjugated antibody. Biodistribution studies with iodine trace-labeled conjugate in nude mice indicated that tumor localization of the gelonin conjugate was decreased compared to unconjugated antibody. However, a significant therapeutic effect of the conjugate was found with multiple but not single dose i.v. treatment in nude mice bearing established palpable melanoma. These in vivo experiments showed that gelonin conjugates are not toxic up to 2 mg total dose/mouse and significantly retarded the growth of established s.c. tumor. Comparison of gelonin conjugates in vitro and in vivo with other A-chain conjugates of 9.2.27 (abrin and ricin) indicated that gelonin had similar potency, better selectivity, better tumor localization, and more significant therapeutic effects.

Exogenous Fc receptors (FcR) have been demonstrated to either augment or inhibit endogenous FcR mediated immunity, immune regulation and gene expression. Other immune regulatory or modulator molecules, such as the H2 histocompatibility antigens, interferon, transfer factor and leukocyte chalones might involve association with or alter the synthesis or status of FcR, thus effecting regulation of immunity and/or gene expression. FcR provide a unique opportunity for eliciting the mechanisms and perhaps altering the immunity and/or gene expression which influence immune regulation, cellular differentiation, viral replication and malignant transformation.

A Graffi murine leukemia was utilized as a model system to investigate the effect of chemoimmunostimulation therapy. Subcutaneous inoculation of approximately 1.0 times 10(6) tumor cells resulted in a rapidly growing tumor at the site of inoculation and subsequent development of splenomegaly and lymphoadenopathy. All animals succumbed to the leukemia within 24 to 30 days. Treatment of diseased animals with two courses of cytoxan over a 2-week period resulted in a remission period of approximately 16 to 18 days before relapse and eventual death of approximately 70% of the drug-treated animals. A significant number of long-term survivors (50 to 83%) was obtained in groups of animals that received combined drug plus BCG or C. parvum therapy. In contrast, the administration of MER (a methanol-extracted residue of BCG) to animals in a drug-induced remission period was no more effective than drug alone. The protective effect afforded by BCG and C. parvum was dependent on the time interval between drug therapy and the administration of the immunostimulators. Treatment of leukemic animals with BCG, C. parvum, or MER alone proved ineffective as all mice died at approximately the same time as untreated control animals. No leukemic cells were observed in any of the histologically examined tissues taken from long-term survivors. The implication of these results for cancer therapy is discussed.

The injection of Staphylococcus-aureus protein A into mice, previously exposed to an antigen (sheep red blood cells), is capable of augmenting or inhibiting a primary delayed hypersensitivity (DH) response. SPA enhances DH response to SRBC when given with a greater than optimal sensitizing dose of the antigen. At antigen doses optimal for eliciting DH to SRBC, SPA inhibited DH. A proposed mechanism for the action of Staphylococcus-aureus protein A is based upon the ability of the protein to function as a Fc cellular receptor, thus neutralizing the effect of antigen-antibody immune complexes on DH. The binding of protein A to the Fc portion of antigen-antibody immune complexes effectively prevents subsequent binding of these complexes to Fc cellular receptors, thus eliminating their participation as co-factors in inter-cellular immunological communication. The ability of protein A to both augment and inhibit DH suggests a role for relative concentrations of serum factors and/or cellular receptors in the regulation of a primary DH response.

A transplantable granulocytic leukemia (GL-13-BC) in strain 13 guinea pigs, which has many similarities to human CML, was used to test the antineoplastic effects of two alkylating agents, busulfan and cyclophosphamide, administered in the late and early stages of the disease. Busulfan had a pronounced cytoreductive effect on circulating leukemic cells in the late, pre-blast crisis stage of this disease but all treated animals, succumbed to the leukemia with only a marginal increase in survival time relative to that of untreated controls. In this respect the guinea pig model resembles human CML. Survival time was moderately increased with early busulfan treatment but, as in the late treatment group, all animals succumbed to the leukemia. A pronounced cytoreductive action on leukemic cells was also observed in guinea pigs treated with cyclophosphamide. Late treatment with this drug produced highly variable effects on the survival time of leukemic guinea pigs; of the nine animals treated, no effect was observe in five, three showed a significant increase in survival time and one animal was still in remission without treatment when the experiment was concluded. Early treatment with cyclophosphamide produced the most striking finding of this study. Two treatments with this drug produced a complete remission in all of the treated guinea pigs. This remission lasted without further treatment for the duration of the study (greater than 200 days) while all untreated controls died within 27-37 days after receiving leukemic cell transplants. The relevance of these findings to the treatment of human CML is discussed.