Consequent intrafamilial immunization for DL-A haplotyping in canines.

A procedure of intrafamilial immunization is described for production of antisera recognizing DL-A haplotypes. In a colony consisting of 1 sire, 6 bitches, and 67 offspring all haplotypes could be accurately allocated. In the colony the observed reaction frequencies of the antisera are in agreement with mendelian codominant inheritance. Mixed lymphocyte culture tests confirmed the accuracy of the serologic typing and the presence of homozygous individuals within the colony. Further evidence is presented supporting the presence of two or more subloci within the DL-A system. Colonies of canines such as the one described should provide a sensitive system for evaluating interaction between serologic DL-A typing, MLC reactivity, and immune response genetics in a nonrodent species which is not highly inbred.

Hemophilia: role of organ homografts.

The concentration of factor VIII and partial thromboplastin times became normal and have remained normal for 140 days after orthotopic tranplantation of a normal liver to a hemophilic dog. Transplantation of a normal spleen into a hemophilic recipient did not result in a significant increase in factor VIII although the splenic graft was viable for at least 47 days. Transplantation of normal marrow to a lethally irradiated hemophilic dog did not result in an increase in factor VIII during 34 days of observation.

Tumor-blocking and -inhibitory serum factors in the clinical course of canine venereal tumor.

An in vitro method for growing colonies of canine transplantable venereal tumor cells in a semisolid agar medium is described. Using autologous or pooled homologous normal dog sera as a feeder layer, 49.3 +/- 3.5 and 47.5 +/- 4.5 tumor colonies were obtained, respectively, when 2 X 10(4) tumor cells were plated. With this assay system, assessment of colony counts provided an accurate and rapid technique for monitoring serum factors in tumor-bearing dogs that inhibited colony formation, or blocked the inhibition of colony formation. In 52 dogs given tumor transplants, a direct correlation was demonstrated between serum activity tested in vitro and the in vivo growth characteristics of the tumor. Tumor cells preincubated with serum from dogs with active tumor growth consistently showed normal colony growth when cultured in agar containing colony-inhibitory sera (blocking effect). In vivo regression was characterized by loss of serum blocking and the development of serum colony-inhibitory activity in culture. In metastatic disease, only blocking activity could be identified, while persistent local invasive disease was characterized by low levels of both blocking and inhibitory serum activity. The sensitivity of this technique coupled with its in vivo predictive capabilities provides a model for monitoring serological responses to a naturally occurring neoplasm in a large, randomly bred animal.

Isolation and characterization of canine venereal tumor-associated inhibitory and blocking factors.

Spontaneous regression of the canine venereal tumor is associated with the production of a serum factor which inhibits in vitro tumor colony-forming units in agar. Logarithmic or persistent tumor growth, on the other hand, is characterized by a serum factor which protects cells against in vitro inhibition (blocking factor). These factors have been characterized by immunochemical methods. Whole regressor and blocking sera were fractionated by Sephadex G-200 filtration and immunoabsorption with rabbit antiserum specific for canine immunoglobulin G2a. Fractions were characterized by immunoelectrophoresis, radial immunodiffusion, and disc gel electrophoresis. In vitro inhibitory and blocking activity of the whole serum was accounted for by the purified immunoglobulin G2a. Blocking activity was also found in protein eluted from logarithmically growing tumors. Preparative polyacrylamide electrophoresis revealed five major fractions with blocking activity only in the immunoglobulin G fraction. Tumor eluates and immunoglobulin G isolated from serially removed tumors demonstrated with the clinical course of the tumor. Using ultrafiltration and sodium dodecyl sulfate electrophoresis of tumor-associated immunoglobulin G at low pH, it was not possible to identify an antigen complexed to the blocking antibody.

Intralesional Bacillus Calmette-Guérin immunotherapy of canine venereal tumors.

Canine transmissible venereal tumors were studied for response to intralesional Bacillus Calmette-Guérin (BCG) therapy. Six pairs of littermates, identical for the major histocompatibility complex, were evaluated. One member of each pair received intralesional BCG to one of two growing tumors. Lesions of control animals received 0.9% NaCl solution. Both injected and noninjected lesions of BCG-treated animals underwent regression within 63 days, as compared to an extended period of tumor growth (beyond 100 days) for controls (p less than 0.05). Serial in vitro assays during therapy included; (a) mixed lymphocyte-tumor culture, (b) phytohemagglutinin stimulation, and (c) assessment of lymphocyte surface markers. Lymphocytes from BCG-treated dogs were significantly more responsive to tumor cells in mixed lymphocyte-tumor culture assay than were those from controls (p less than 0.05). Maximal responses occurred during tumor regression. T- and B-lymphocyte levels as assayed by rosette formation and surface marker immunoglobulins were not influenced by BCG therapy. It was concluded that intralesional BCG therapy of canine venereal tumors was highly effective in causing regression of injected and noninjected lesions. This tumor model system may be useful for the evaluation of the effectiveness of new immunotherapeutic approaches on established neoplasms in large, randomly bred animals.

Serum cyclophosphamide activity in patients treated for small cell carcinoma of the lung.

Cyclophosphamide requires in vivo activation for its cytotoxicity. A bioassay of serum cyclophosphamide activity based on inhibition of normal peripheral blood CFU-C by serum from cyclophosphamide-treated patients was developed. Seventeen patients with small cell cancer of the lung were studied before and after cyclophosphamide administration in an attempt to correlate serum cytotoxicity in vitro with clinical response to chemotherapy. A correlation (r = 0.61, p less than 0.01) was discovered between serum cytotoxicity in vitro and subsequent leukopenia in vivo. However, a dose-response relationship was not found between serum cytotoxicity and response to chemotherapy. Besides drug dosage and blood level, other factors govern the sensitivity of small cell lung cancer to chemotherapy.

High-dose combination alkylating agent therapy with autologous bone marrow rescue for refractory solid tumors.

Twenty-six adults, ages 27 to 60, with refractory metastatic solid tumors were treated with high-dose cyclophosphamide (Cy) + carmustine (BCNU) at one of three escalating dose schedules followed by autologous bone marrow transplantation (ABMT). Toxicity was severe and dose-related, with the maximum tolerated dose for the combination determined to be Cy 160 mg/kg and BCNU 900 mg/m2. Median time to WBC recovery (greater than or equal to 1,000/microL) was 13 days post-ABMT (range, nine to 22 days) and to a platelet count of greater than or equal to 50,000/microL, 22 days (range, 13 to 83 days). Sixteen of 20 evaluable patients (80%) responded to therapy with at least 50% reduction in measurable tumor, and three patients achieved complete remission (CR). Responders included eight of nine evaluable patients with breast carcinoma, two of five with melanoma, two of two with sarcoma, and four of four with colon carcinoma. Response durations were short (median, 4 months), even for complete responders, and relapses generally occurred at sites of previous metastases. In order for this approach to have a more significant impact on overall survival, it may need to be applied earlier in the natural history of the malignancy.

Kinetics and effects of activated cyclophosphamide in serum.

The effects of sera containing in vivo activated cyclophosphamide were tested on macrophage granulocyte colony growth (CFUc) and mixed leukocyte cultures (MLC). Bone marrow reconstitution and the growth of a canine tumor after incubation of transplanted cells with active sera were studied in vivo. The following experiments were performed: 1) peripheral blood CFUc values were determined in 6 dogs 5 min to 72 h after intravenous administration of 100 mg/kg cyclophosphamide. Inhibition was apparent at 5 min and lasted for 24 h. 2) Sera samples were obtained from 10 dogs after cyclophosphamide administration. The half life of serum inhibitory activity measured against normal dog cells was approximately 6 h. Inhibitory effects were noted 5 min following drug administration and complete at 30 min. 3) Timed incubation with 1 h postcyclophosphamide sera revealed preferential inhibition of MLC activity compared to CFUc activity, 4) In vitro incubation for 30 min in active sera did not affect the bone marrow repopulating potential of hematopoietic cells compared to nonincubated cells. 5) At least a tenfold reduction in the growth potential of a transplantable canine tumor could be produced by in vitro incubation of tumor cells with active sera. It is concluded that varying sensitivities of hematopoietic, immunocompetent and tumor cell populations to cyclophosphamide metabolites may provide a basis for in vitro chemoseparation of mixtures of these cell types.

Autologous bone marrow infusion following high dose chemotherapy of the canine transmissible venereal tumor (TVT).

The present study was undertaken to evaluate infusion of cryopreserved autologous bone marrow following supralethal chemotherapy in canines bearing a solid tumor thought to be moderately sensitive to cytotoxic agents. Initial studies in 5 dogs established a combination of busulfan (Bu) 3 mg/kg X 2 days and cyclophosphamide (Cy) 50 mg/kg on day 3 to produce bone marrow lethality within 14 days (high dose regime). Bu 1 mg/kg, Cy 20 mg/kg produced tolerable toxicity (low dose regime). Eight pairs of dogs were challenged with 3 X 10(8) transmissible venereal tumor cells. Measurable progressive tumor growth occurred in all instances. Marrow aspirated from the femoral shafts of the animals was cryopreserved in 10% DMSO. One dog of each pair received the high dose Bu + Cy regime followed in 30 h by marrow infusion and his partner received the low dose regime without marrow. Tumors were measured serially for at least 2 months. Infusion of marrow resulted in evidence of hematologic recovery within 2 weeks following the high dose regime. Tumor responses occurred in both groups when compared to 8 untreated tumor challenged controls. High dose animals had greater initial responses than low dosed dogs but long term responses were not significantly different. Eight dogs rechallenged with tumor cells after initial successful therapy failed to develop tumors. It was concluded that: a) cryopreserved autologous bone marrow infusion was effective in protecting tumor bearing canines from otherwise lethal chemotherapy; b) the transmissible venereal tumor of canines responded to both high and low dose regimes; c) the rescue of dogs by stored autologous marrow did not offer additional benefits in tumor control over a standard regime; d) chemotherapy treated dogs resisted tumor rechallenge. This model may offer a large animal system to study the autologous marrow rescue concept during controlled periods of tumor evolution.

Processing of peripheral blood stem cells for transplantation.

Canines were studied to determine the efficacy of peripheral blood collection by semicontinuous centrifugation to procure sufficient numbers of hematopoietic cells for marrow reconstitution. CFU-C assays on fresh and cryopreserved peripheral blood cells were compared to bone marrow aspirates. Attempts were made to partially separate hematopoietic cells from immunocompetent cells during buffy coat collection and by incubation with activated cyclophosphamide. Yields from 4 runs of semicontinuous centrifugation averaged 1.7 x 10(5) CFU-C compared to 1.9 x 10(5) CFU-C for standard marrow aspiration. Ratios of approximately 5/1 marrow to peripheral blood mononuclear cells (MNC) were found. Autologous transplantation with 1.6 x 10(4) CFU-C per kg resulted in evidence of marrow reconstitution within two weeks following otherwise lethal chemotherapy. Recovery of CFU-C following cryo-preservation was 82% for marrow and 78% for peripheral blood. Selective depression of MLC activity occurred when peripheral blood MNC were incubated for 30 minutes with activated cyclophosphamide. MLC was inhibited by greater than 90% while 70% of CFU-Cs were retained. It was concluded that peripheral blood may be a practical alternative to marrow for transplantation studies.

Hemopoietic colony forming units in fresh and cryopreserved peripheral blood cells of canines and man.

Colony forming units (CFUa) were assayed in the peripheral blood and separated mononuclear cells of canines and man. Fresh and cryopreserved samples were studied. By plating 3 x 10-5 canine buffy coat cells or 3 x 10-6 human buffy coat cells between 33 plus or minus 6.6 and 38 plus or minus 1.0 colonies were observed. A high degree of reproducibility was shown for duplicate plates and on repeated testing. Cryopreservation for a one-month period resulted in a minimal recovery of 80 per cent CFUa for canine cells and 96 per cent for human cells. In vivo correlation between peripheral blood CFUa and marrow repopulation was assessed indogs following supralethal whole body irradiation. Prompt repopulation of the marrow was observed and this correlated well with the CFUa assay following infusion of stored buffy coat cells. It was concluded that the peripheral blood of both man and dog have significant numbers of cells with CFUa capabilities that may be potentially useful for marrow grafting purposes.

Treatment of systemic candidiasis in neutropenic dogs with ketoconazole.

The present study evaluated the activity of ketoconazole in neutropenic dogs with systemic candidiasis. Five dog pairs were made neutropenic by intravenous cyclophosphamide (50 mg/kg) and challenged with either 10(6) or 10(7) colony-forming units (CFU) of Candida albicans. Half of the dogs received ketoconazole (10 mg/kg) daily beginning 24 h after challenge. All were killed at 96 h and liver, spleen, and kidney were cultured. Of four dogs given 10(6) CFU, two untreated dogs had 9 X 10(3) to 1 X 10(5) CFU/g wet tissue, compared to 0 CFU in ketoconazole-treated dogs. With inoculum increased to 10(7) CFU, three untreated dogs had 2 X 10(4) to 3 X 10(5) CFU/g wet tissue, while three ketoconazole dogs had 0-5 X 10(3) CFU/g wet tissue. The effect of ketoconazole on autologous marrow reconstitution in dogs with systemic candidiasis was examined by infusing autologous cryopreserved marrow into four dogs one day after lethal whole body irradiation (800 rad). Once neutropenic, they were challenged with 10(7) CFU of C. albicans. Two dogs received no ketoconazole and died of disseminated candidiasis, without marrow reconstitution. Two dogs received ketoconazole for 25 days. Prompt marrow recovery occurred and they remained healthy. There was no evidence of infection at death. These studies quantitatively demonstrate the in vivo effectiveness of ketoconazole in reducing tissue infection with C. albicans in neutropenic dogs. They provide in vivo evidence that ketoconazole can prevent or cure systemic candidiasis in the bone marrow transplant setting without significant inhibition of marrow recovery.

The collection, preservation and function of peripheral blood hematopoietic cells in dogs.

Semicontinuous flow centrifugation (SFC) was employed in canines to obtain adequate numbers of cells for autologous marrow repopulation following supralethal cyclophosphamide administration (100 mg per kg). Four cycles using a 225 ml bowl and 30 ml per minute flow rate were carried out for procurement. Collections averaged 8.4 +/- 0.4 x 10(9) (n = 30) leukocytes. Mononuclear cells (MNC) comprised 75 +/- 2% of the population and granulocyte colony-forming units (CFU-C) totaled 1.9 +/- 0.09 x 10(5) colonies per collection. Eighty-six percent of mononuclear cells were "T" cells in the 30 to 90 second fraction compared to 49% at 150 to 120 seconds. CFU-C fractionation revealed a peak at 30-210 seconds and a second peak at 120-210 seconds. Following programed freezing and rapid thawing 77.7 +/- 11.4% of CFU-C were recovered. Using a dose of 1 x10(9) MNC per kg for reinfusion, marrow repopulation and clinical recovery occurred in four out of four dogs. It was concluded that 1) SFC was effective for obtaining adequate numbers of peripheral blood stem cells for autologous marrow repopulation. 2) A rapid thawing and direct transfusion technique appears satisfactory for administration. 3) Some separation of "T", "B" and CFU-C peripheral blood components is possible by centrifugation.

Plasmapheresis as immunotherapeutic modality in the treatment of the canine venereal tumor.

Plasmapheresis was evaluated as a treatment modality for the transmissible venereal tumor (TVT) of the dog. The TVT is a unique tumor because of its capability for transplantation as a homograft between untreated randomly bred dogs and is characterized by the presence of dog leukocyte antigen (DLA) determinants on its tumor cells and reactivity in the mixed leukocyte tumor cell culture (MLTC). In the progressing phase, high titers of blocking antibodies measurable in the MLTC were noted. The purpose of this study was to evaluate the influence of plasmapheresis on the growth of established TVT and to correlate tumor response with the removal of blocking factors. Six pairs of DLA-identical dogs were used as experimental and control animals. Plasmapheresis was performed by discontinuous centrifugation using the Hemonetics model 30. An average of 1100 +/- 120 ml of plasma was exchanged on consecutive days during the third week after tumor injection. Consistently lower growth rates were observed in 2 experimental dogs, but there was no early rejection. Sera taken at day 14 of tumor growth contained significant blocking activity in all 12 dogs. Sera obtained post-plasmapheresis showed a decrease of blocking activity in all 6 experimental dogs, P less than 0.001. The TVT appears to be a suitable model for preclinical studies of plasmapheresis alone and in combination with other modalities.

Restoration of hematopoiesis in dogs by infusion of cryopreserved autologous peripheral white cells following busulfan-cyclophosphamide treatment.

Canine cryopreserved autologous peripheral buffy coat cells were infused after an otherwise lethal regime of busulfan and cyclophosphamide. In seven dogs so treated, restoration of hematopoiesis occurred within 7 days, and six dogs recovered completely. Comparable colony-forming unit in agar activity was present in freshly processed and cryopreserved buffy coat cells and proved to correlate with in vivo marrow recovery. It was concluded that the peripheral blood is a convenient source for obtaining cells for autologous marrow reconstitution in canines.

A canine model for hepatic venoocclusive disease.

Hepatic venoocclusive disease is a frequent lethal complication of bone marrow transplantation. It has also been associated with hepatic irradiation and administration of chemotherapeutic agents without BMT. The pathogenesis and therapy of VOD are unclear. The present studies were directed at developing a canine model for VOD. Three groups of dogs were studied. Group one consisted of 8 dogs in which monocrotaline (MC) was administered at 125 mg/kg orally on an intermittent schedule. In 7 of the 8 dogs 6 to 9 doses of drug were administered between 42 and 110 days. Group 2 consisted of 6 dogs receiving busulfan 2 mg/kg/day for 17-25 days, when platelet counts decreased to less than 5 x 10(4)/mm3 or clinical bleeding occurred. Group 3 consisted of 2 dogs receiving 24 Gy and 4 dogs receiving 36 Gy of whole-liver irradiation. Seven of 8 dogs in group 1 developed significant liver function abnormalities and evidence of portal hypertension. Histologic findings of VOD were present at autopsy. Group 2 dogs failed to develop clinical or laboratory liver abnormalities, but 3 of 6 animals had minimal histologic evidence of VOD. Three of 6 dogs in group 3 receiving 36 Gy developed hepatic dysfunction and had findings of fibrosis at autopsy. It was concluded that MC administration produced consistent clinical and histologic features of VOD in dogs. Changes occurring after busulfan or total-liver irradiation administration were less reproducible. Dogs are a suitable large-animal model for studies of VOD.

Long-term results of autologous marrow transplantation for relapsed or refractory male or female germ cell tumors.

Twenty-one patients with relapsed or refractory germ cell tumors were treated with high-dose chemotherapy and marrow transplantation (HDC/BMT) from 1982-1993. Primary sites of disease were testis (17), ovary (three), and pineal gland (one). Pathology included dysgerminoma (one), choriocarcinoma with adenocarcinoma (one), seminoma (four), and nonseminoma or mixed germ cell tumor (15). Nineteen had at least two prior chemotherapy regimens and eight had cisplatin-refractory disease defined as progression within 4 weeks of a cycle of cisplatin-based chemotherapy. HDC regimens were mostly combinations of cyclophosphamide with etoposide and cisplatin or carboplatin. There were only two treatment-related deaths (aspergillosis and interstitial pneumonitis). Times to engraftment of granulocytes (21+/-8.3 days) and platelets (32+/-20.2 days) were reasonable with only the last nine patients receiving growth factors. At a minimum of 4 years follow-up, eight patients have died of disease, six of whom were cisplatin-refractory prior to transplant. Eleven patients (52% overall) are alive and continuously free of disease after 4-10 years including one of three with refractory ovarian germ cell tumor. HDC/BMT provides significant long-term disease-free survival as salvage therapy for both male and female relapsed germ cell tumor patients who are not refractory to cisplatin.

High-dose carboplatin, etoposide and cyclophosphamide with autologous bone marrow transplantation for the treatment of advanced malignancies: a phase I study.

Carboplatin is a platinum-derivative widely used in conditioning regimens with ABMT, particularly in combination with cyclophosphamide and etoposide, drugs which co-express synergism in vitro. The objective of this study was to determine the maximum tolerated dose (MTD) of this combination. Thirty-four patients with refractory lymphoid or solid tumors were treated in a dose-escalation study with continuous infusion carboplatin (1.2-2 g/m2) on days -7 to -4, etoposide (1.2-2.4 g/m2) on days -7 to -5 and cyclophosphamide (120 mg/kg) given in two dose schedules: (1) day -3, -2; (2) day -9, -8. Autologous bone marrow or peripheral blood stem cells were infused on day 0. Mucositis/enterocolitis was dose limiting. In addition, severe cardiac dysfunction occurred in schedule 1 but not in schedule 2. Renal dysfunction occurred in the setting of fungemia, respiratory failure and congestive heart failure, and did not correlate with carboplatin dose. Hepatic and pulmonary dysfunction were minimal. The MTD was etoposide 2.1 g/m2 and carboplatin 2.0 g/m2, in combination with cyclophosphamide (120 mg/kg) on schedule 2. Responses were seen in 16 of 19 patients with measurable disease. Seven patients are disease-free survivors 50-60+ months post-ABMT. This study defines the MTD of carboplatin when combined with etoposide and cyclophosphamide in patients with adequate renal function and suggests significant anti-tumor activity.

A rat model of syngeneic bone marrow transplantation during breast cancer therapy.

The purpose of this study was to develop a breast cancer model in rats, in which myeloablative chemotherapy and syngeneic bone marrow transplantation (SBMT) could be evaluated systematically for therapeutic effect. The Wistar-Furth (WF) DMBA-4 breast cancer cell line transplanted into naive WF rats produced rapidly growing tumors that were lethal within 2 months. SBMT was performed following preparation with a regimen (Bu-Cy), consisting of busulfan 16 mg/kg by gastric gavage on days -3 and -2 followed by 250 mg/kg of cyclophosphamide i.p. on day -1. Marrow was prepared from the femurs of donors and infused i.v. into the recipient on day 0. In all, 15 rats treated with Bu-Cy without marrow died, while 22 of 25 transplanted rats survived. In total, 16 rats with measurable tumors showed tumor responses following transplantation, but tumors recurred and survival was minimally prolonged. Of nine rats transplanted before clinical tumors were detected, five became long-term survivors that resisted further tumor challenge. It was concluded that the DMBA-4 breast cancer in WF rats could serve to evaluate SBMT following myeloablative doses of chemotherapy at various tumor loads. At large tumor loads therapy was not curative, but at low tumor burdens cures were possible and resistance to subsequent tumor challenge was demonstrated. The model may be useful for further studies of stem cell infusion in rodent tumor systems.

Radiation-induced hemopoietic death in mice as a function of photon energy and dose rate.

Radiation-induced hemopoietic death was measured in mice exposed to photons of four different energies: 250-kVp X rays, 60Co gamma rays (1.25 MeV), and 6- and 25-MV photons from a linear accelerator. For each radiation source, the lethal dose which killed 50% of the population in 30 days (LD50/30) associated with the hemopoietic syndrome was determined in groups of mice exposed to graded doses from 600 to 1150 cGy at dose rates of 20, 40, and 80 cGy/min. The calculated LD50/30 values for 25 and 6 MV were significantly different from each other at all exposure rates while no difference was observed between 6 MV and 60Co. Using 60Co gamma rays as the standard, the relative biologic effectiveness was as follows: 250 kVp greater than 25 MV greater than 6 MV = 60Co. The data suggest that there may be a greater damage to tissue within the marrow cavities following exposure to very high megavoltage radiation, a factor which must be considered with the increasing utilization of linear accelerators in the clinic and laboratory.