The effect of antineoplastic agents on the healing of small intestinal anastomoses in the rat

The influence of an intravenous 5-day combined chemotherapy with bleomycin (2 mg/kg/d), 5-fluorouracil (10 mg/kg/d) and cis-diamminedichloroplatinum (0.35 mg/kg/d) on the healing of ileal anastomoses was investigated in rats. Ninety-six male Wistar rats were used, divided into four groups. The rats in the control group had surgery without administration of cytostatic agents. The other rats were operated either 2 days after, 2 days before, or during the 5-day chemotherapy course. In each group, rats were killed after 3, 7, and 21 days. Anastomotic healing was assessed by measurement of bursting pressures and hydroxyproline levels. Intestinal healing appeared to be impaired most if the operation was performed in the middle of the antineoplastic chemotherapy course. The effects were most pronounced on the seventh postoperative day. Surgery on the second day after the chemotherapy course led to a slight and early delay in wound healing as measured by the hydroxyproline content. Seven days postoperatively, concentrations had returned to preoperative values. Surgery 2 days before chemotherapy induced only minor differences with respect to the control group. In all groups, bursting pressure and hydroxyproline content at 21 days were similar. Thus, antineoplastic agents retard but do not prevent healing of intestinal anastomoses. The effects are most pronounced when surgery is performed during chemotherapy. If possible, surgery should be performed prior to chemotherapy. Increasing the time interval between surgery and chemotherapy may decrease the delay in intestinal woundhealing.     

Treatment of micrometastases from Lewis lung carcinoma with abrin and cyclophosphamide, given singly and in combination.

The effect of the plant toxin abrin and of cyclophosphamide given as adjuvant chemotherapy after irradiation of the primary tumor was studied in mice bearing intramuscularly growing Lewis lung carcinoma. The chemotherapy was given immediately after irradiation performed 9 days after inoculation of 10(5) tumor cells. The drugs were given in bolus injections either as single agents or concurrently. The therapeutic effect was assessed by recording the appearance of lung metastases on day 21 or the number of long-term survivors, i.e. animals alive at day 60. In the control group 21 +/- 3.4 (SD) macroscopic lung colonies was recorded on day 21. Mean survival time was 25.5 days with none of the mice alive at day 60. The optimal abrin dose (612.5 ng/kg IV) reduced the number of lung metastases to 2.6 +/- 0.8 and yielded 37% long-term survivors (11/30). The optimal dose of cyclophosphamide (150 mg/kg IP) reduced the number of lung colonies to less than 1 and yielded 61% survivors (14/23). Small to moderate doses of abrin significantly potentiated the therapeutic effect of cyclophosphamide without increasing the toxicity. The best results (18/20 or 90% long-term survivors) were obtained when the optimal dose of cyclophosphamide, 150 mg/kg, was combined with 350 ng/kg of abrin. The results obtained in this highly resistant tumor suggest that combinations of the two drugs may be useful also in other tumor types.     

Healing of experimental colonic anastomoses: effect of antineoplastic agents

The effect of a combination of antineoplastic agents (bleomycin (2 mg/kg/d), 5-fluorouracil (10 mg/kg/d) and cisdiamminedichloroplatinum (0.35 mg/kg/d)), given intravenously, on the healing of colonic anastomoses was investigated in rats. Ninety-six male Wistar rats were divided into four groups. A control group of rats underwent surgery only. The remaining rats were operated either 2 days before, 2 days after or during the 5-day chemotherapy course. In all groups rats were killed after 3, 7 and 21 days. Wound healing of the anastomosis was assessed by measuring the bursting pressures and hydroxyproline contents. Operating in the middle of the 5-day chemotherapy course had the greatest effect on anastomotic healing. This was most apparent on the seventh day postoperatively. When surgery was performed on the second day after the chemotherapy course there was an early delay in wound healing as measured by hydroxyproline content. Seven days postoperatively concentrations were in the same range as those in the control group. Chemotherapy commencing 2 days after surgery did not affect anastomotic healing as compared to the control group. Bursting pressure and hydroxyproline content at the end of the experiment were more or less comparable in all groups.     

Rational selection of adjuvant chemotherapy after cytoreduction surgery for murine neuroblastoma

Improving the prognosis of advanced neuroblastoma remains an important yet unachieved goal of pediatric oncology, a fact which may be related to an insufficient analysis of the role played by cytoreductive surgery. Utilizing strain A mice bearing C-1300 syngeneic neuroblastoma, tumor biology and host immunocompetence were studied after cytoreduction surgery and adjuvant chemotherapy. Cell kinetic analysis in the residual tumor demonstrated an increase of the proliferative fraction 18 to 42 h after operation, but the same peak proliferation was delayed in bone marrow cells to 24 to 96 h. The potential for drug distribution to the tumor after cytoreduction surgery was assessed by injecting Na251CrO4 and measuring tumor uptake. There were two significant (P less than 0.05) peaks of activity at 6 h and 3 days, suggesting local edema and neovascularity, respectively. Injection of both cell cycle specific and nonspecific adjuvant chemotherapeutic agents in a dosage of one-fourth of their 50% lethal dose at 24 or 72 h following surgical cytoreduction did not induce any antitumor activity at either injection time. However, when cyclophosphamide was given in this dose, the C-1300 tumor growth was impaired, an effect which was largely abrogated by first subjecting the tumor bearer to thymectomy and irradiation. The transfer of spleen cells from adjuvant cyclophosphamide-treated mice to tumor-inoculated normal mice significantly delayed tumor appearance when comparison was made with animals treated by operation alone, and such recipients also exhibited a more prolonged survival. These data suggest that the antitumor activity of cyclophosphamide following cytoreduction surgery of C-1300 neuroblastoma is mediated by both pharmacological and immunological mechanisms.     

Chemotherapy-induced pulmonary toxicity in mice bearing L1210 leukemia

Fatal pulmonary toxicity can be consistently produced in L1210 leukemia-bearing mice by single therapeutic doses of cyclophosphamide, BCNU, and mitomycin C but not by adriamycin. Lung toxicity is principally determined by an existing tumor burden at the time of drug administration. Thus when any of the four chemotherapeutic agents was given 5 days after L1210 transplantation there was no mortality. Pulmonary pathology in these mice was equivalent to that noted in normal mice receiving identical drug treatment or to that noted in untreated L1210-bearing mice sacrificed 7, 8, or 10 days after tumor transplantation. When chemotherapy was delayed to day 7 after L1210 transplantation for mitomycin C or to day 8 after transplantation for BCNU and cyclophosphamide, more severe pulmonary toxicity was found. Mortality within the first 5 days of treatment was 38, 50, and 80%, respectively. Pulmonary pathology included moderate to severe vascular congestion and interstitial pneumonitis, diffuse pulmonary hemorrhage often involving the entire pulmonary parenchyma, pulmonary edema, and alveolar cell metaplasia. A unique finding, associated with cyclophosphamide treatment, was the occurrence of perivascular-intramural edema of the walls of medium-size pulmonary vessels. It is hypothesized that stasis within the pulmonary capillary circulation, resulting from advanced tumor growth and from drug treatment, may contribute to the development of chemotherapy-related toxicity.     

Radiation effect in mouse skin: dose fractionation and wound healing

Radiation induced dermal injury was measured by the gain in the physical strength of healing wounds in mouse skin. A sigmoid dose response for the inhibition of wound healing 14 days after surgery was found for single doses of X rays. The sparing of dermal damage from fractionation of the X-ray dose was quantified in terms of the alpha/beta ratio in the linear-quadratic (LQ) model, at a wide range of doses per fraction reaching as low as about 1 Gy. The fit and the appropriateness of the LQ model for the skin wound healing assay was examined with the use of the Fe-plot in which inverse total dose is plotted versus dose per fraction for wound strength isoeffects. The alpha/beta ratio of the skin was about 2.5 Gy (95% confidence of less than +/- 1 Gy) and was appropriate over a dose range of 1 Gy to about 8 Gy. The low alpha/beta value is typical for a late responding tissue. This assay, therefore, has the advantage of measuring and forecasting late radiation responses of the dermis within a short time after irradiation.     

Cure of advanced L1210 leukemia after correction of abnormal red blood cell deformability

Summary Chemotherapeutic efficacy is inversely related to pretreatment tumor burden. A possible contributory factor in chemotherapy resistance is the occurrence of decreased red blood cell deformability in mice with advanced tumors. Poorly deformable red blood cells may prevent adequate drug delivery to tumor cells. Two methods for improving red cell deformability were found in this study. The first involved treatment of L1210 leukemia-bearing mice with red cell metabolic substrates, including inosine, adenosine, glucose, sodium pyruvate, and ascorbic acid. The combination of inosine plus sodium pyruvate (3 mg of each drug in 0.5 cm³ phosphate-buffered saline) was most effective in restoring deformability to normal. Administration of an active chemotherapeutic agent (BCNU or cyclophosphamide) also improved red cell deformability, with maximal restoration occurring 4–5 days after drug treatment. Standard and 50% of standard drug doses were equally effective in restoring deformability. The optimal therapy program for day 7 L1210 leukemia utilized inosine plus sodium pyruvate given 10–15 min before BCNU 15 mg/kg on day 7 and before BCNU 30 mg/kg on day 12. This treatment yielded 44% cures, whereas BCNU alone, in identical dose and schedule, gave no cures. Median survival was 50 days for the inosine-pyruvate-treated mice, as against 30 days for BCNU alone. Therefore, treatment with non-toxic doses of red blood cell metabolic substrates plus optimal timing of chemotherapy, two maneuvers that significantly increased red blood cell deformability, resulted in significant therapeutic benefit.     

Maximum tolerable dose and low-dose metronomic chemotherapy have opposite effects on the mobilization and viability of circulating endothelial progenitor cells

There is growing evidence that vasculogenesis (progenitor cell-derived generation of new blood vessels) is required for the growth of some neoplastic diseases. Here we show that the administration of cyclophosphamide (CTX) at the maximum tolerable dose with 21-day breaks or at more frequent low-dose (metronomic) schedules have opposite effects on the mobilization and viability of circulating endothelial progenitors (CEPs) in immunodeficient mice bearing human lymphoma cells. Animals treated with the maximum tolerable dose CTX experienced a robust CEP mobilization a few days after the end of a cycle of drug administration, and tumors rapidly became drug resistant. Conversely, the administration of metronomic CTX was associated with a consistent decrease in CEP numbers and viability and with more durable inhibition of tumor growth. Our findings suggest that metronomic low-dose chemotherapy regimens are particularly promising for avoiding CEP mobilization and, hence, to potentially reduce vasculogenesis-dependent mechanisms of tumor growth.     

Solid tumor models for the assessment of different treatment modalities. XXII. The alternate utilization of radiotherapy and chemotherapy

Major increases in the time between administration of two modalities, radiation and cyclophosphamide (CP), from 1 to 7 days and in the overall time of delivery of 3 courses of combined therapy from 24 to 35 days were carried out in rats with hepatoma 3924A without major loss of therapeutic effectiveness. Cure rates of 50% or greater could be maintained even though treatment was given over much longer time periods. The radiation was given as hyperfractionated, split-course schedules which were devised by increasing the number of 250 rad fractions over a 2-day period. In one series of experiments these 2-day schedules were given at 11-day intervals for 3 courses on days 0 and 1, 11 and 12, 22 and 23; and CP (150 mg/kg) was given 1 day after each of the 3 radiation courses on days 2, 13, and 24. In the second series of experiments radiation was given on days 0 and 1, 14 and 15, 28 and 29; and this was alternated with 3 single doses of CP given 1 week after each of the 3 courses of radiation, on days 7, 21 and 35. Increasing the total radiation dose from 6000 to 7500 rad in the series given CP 1 day after each of three courses of radiation results in an increase in total tumor cure rates from 50% to 60%. The tumor cure rate in the series given CP 7 days after radiation increased from 10% to 70% when the total radiation dose was increased from 6000 to 7500 rad. Increasing the total radiation dose from 6000 to 7500 rad increased the magnitude of the acute skin reaction as well as the duration of recovery. However, the skin reactions for both the 6000 and 7500 rad were acceptable. Host toxicity and normal tissue reaction were within acceptable limits for both modalities. The results of these studies, therefore, indicate that excessive toxicity, one of the major deterrents to the effective combined utilization of these two primary means of cancer management, may be avoided by temporal separation of delivery while maintaining tumor cure rates of 50% or greater.     

Preclinical study of the systemic toxicity and pharmacokinetics of 5-iodo-2-deoxypyrimidinone-2'-deoxyribose as a radiosensitizing prodrug in two, non-rodent animal species: implications for phase I study design.

We have demonstrated previously an improved therapeutic index for oral 5-iodo-2-deoxypyrimidinone-2'-deoxyribose (IPdR) compared with oral and continuous infusion of 5-iodo-2'-deoxyuridine (IUdR) as a radiosensitizing agent using three different human tumor xenografts in athymic mice. IPdR is a prodrug that is efficiently converted to IUdR by a hepatic aldehyde oxidase, resulting in high IPdR and IUdR plasma levels in mice for > or =1 h after p.o. IPdR. Athymic mice tolerated oral IPdR at up to 1500 mg/kg/day given four times per day for 6-14 days without significant systemic toxicities. In anticipation of an investigational new drug application for the first clinical Phase I and pharmacology study of oral IPdR in humans, we studied the drug pharmacokinetics and host toxicities in two non-rodent, animal species. For the IPdR systemic toxicity and toxicology study, twenty-four male or female ferrets were randomly assigned to four IPdR dosage groups receiving 0, 15, 150, and 1500 mg/kg/day by oral gavage x 14 days prior to sacrifice on study day 15. All ferrets survived the 14-day treatment. Ferrets receiving 1500 mg/kg/day showed observable systemic toxicities with diarrhea, emesis, weight loss, and decreased motor activity beginning at days 5-8 of the 14-day schedule. Overall, both male and female ferrets receiving IPdR at 1500 mg/kg/day experienced significant weight loss (9 and 19%, respectively) compared with controls after the 14-day treatment. No weight loss or other systemic toxicities were observed in other IPdR dosage groups. Grossly, no anatomical lesions were noted at complete necropsy, although liver weights were increased in both male and female ferrets in the two higher IPdR dosage groups. Histologically, IPdR-treated animals showed dose-dependent microscopic changes in liver consisting of minimal to moderate cytoplasmic vacuolation of hepatocytes, which either occurred in the periportal area (high dosage group) or diffusely throughout the liver (lower dosage groups). Female ferrets in the highest IPdR dose group also showed decreased kidney and uterus weights at autopsy without any associated histological changes. No histological changes were found in central nervous system tissues. No significant abnormalities in blood cell counts, liver function tests, kidney function tests, or urinalysis were noted. Hepatic aldehyde oxidase activity was decreased to approximately 50 and 30% of control ferrets in the two higher IPdR dosage groups, respectively, after the 14-day treatment period. The % IUdR-DNA incorporation in ferret bone marrow at the completion of IPdR treatment was < or =0.05% in the two lower dosage groups and approximately 2% in the 1500 mg/kg/day dosage group. The % IUdR-DNA in normal liver was < or =0.05% in all IPdR dosage groups. In a pharmacokinetic study in four Rhesus monkeys, we determined the plasma concentrations of IPdR after a single i.v. bolus of 50 mg/kg over 20 min. Using a two-compartment model to fit the plasma pharmacokinetic data, we found that IPdR was cleared in these non-human primates in a biexponential manner with an initial rapid distributive phase (mean T1/2alpha = 6.5 min), followed by an elimination phase with a mean T1/2 of 63 min. The mean maximum plasma concentration of IPdR was 124+/-43 microM with a mean total body clearance of 1.75+/-0.95 l/h/kg. IPdR was below detection (<0.5 microM) in the cerebrospinal fluid. We conclude that there are dose-limiting systemic toxicities to a 14-day schedule of p.o. IPdR at 1500 mg/kg/day in ferrets that were not found previously in athymic mice. However, no significant hematological, biochemical, or histopathological changes were found. Hepatic aldehyde oxidase activity was reduced in a dose-dependent in ferret liver, suggesting partial enzyme saturation by this IPdR schedule. The plasma pharmacokinetic profile in Rhesus monkeys showing biexponential clearance is similar to our published data in athymic mice. These data are being applied     

Partial nephrectomy in mice with milliwatt carbon dioxide laser and its influence on experimental metastasis

We have developed a surgical model to perform partial nephrectomy in mice using the milliwatt CO2 laser and have used this model for studying the influence of the sequel of surgery on experimental tumor metastasis. Strain A mice were subjected to partial nephrectomy using the milliwatt CO2 laser. The surgical procedure was time efficient, the blood loss was minimal, and the postoperative mortality was 6%. Immediately after surgery, the wound consisted of a superficial layer of charring and a deeper layer of thermal damage (coagulative necrosis). The wound healing was completed within 30 days and was accompanied by fibroblast infiltration and tubular regeneration but minimal inflammatory response. Seventy surgical mice were injected I.V. with TA3Ha murine mammary adenocarcinoma cells at different intervals (immediately to 30 days) after surgery. Among 38 mice inoculated with tumor cells immediately or up to 3 days after surgery, 18 (47%) showed histologically confirmed tumors at the site of surgical trauma. None of the 38 unoperated kidneys showed any evidence of tumor. This difference is statistically significant at a P value of less than 0.001. As the interval between surgery and tumor inoculation was increased to 7, 15, and 30 days, the frequency of tumor formation at the site of surgery decreased to 20% (2/10), 14% (2/14), and 0% (0/8), respectively. The results demonstrate that a) partial nephrectomy in mice is feasible with minimal mortality or apparent morbidity, b) the laser-induced surgical trauma favors implantation and growth of tumors, c) the frequency of tumor formation is related to the stage of wound healing, and d) the tumors are anatomically related to the healing wound but do not invade into the parenchymal tissue.     

Doxorubicin-induced impairment of wound healing in rats

The mortality rate induced by 3 doses of iv doxorubicin was evaluated in F344 rats, and a dose of 8 mg doxorubicin/kg body weight was the maximum dose tolerated with an acceptable mortality rate. Rats treated with 8 mg doxorubicin/kg prior to or on the day of wounding demonstrated decreased wound breaking strength in incisional wounds at all intervals after wounding. Decreased amounts of collagen and DNA and less cellularity were noted in wound chambers from rats treated in the same manner. In both the incisional wound and wound chamber models, rats treated with doxorubicin 7 days after wounding showed a less dramatic healing impairment. No difference in collagen types was noted between chambers from the doxorubicin-treated and untreated rats. Doxorubicin also produced a significant reduction in platelet and white blood cell counts 1 week after it was administered. The data indicate that doxorubicin impedes healing by decreasing wound cellularity and collagen synthesis.     

Feasibility of combined modality therapy for localized high-grade soft tissue sarcomas in adults.

Seventeen consecutive patients with localized, high grade soft tissue sarcomas had resection of their primary tumor, radiation therapy and chemotherapy. The soft tissue sarcoma was primary in 14 patients and regionally recurrent in 3 patients. Chemotherapy consisted of cyclophosphamide 500 Mg/M² day 1, Adriamycin (ADR) 60 mg/M² day 2, and DTIC 400 Mg/M² days 1 and 2, given every 21 days to a maximum ADR dose of 450 mg/M². Cyclophosphamide and DTIC were then given to a total duration of 1 year. Radiation therapy consisted of 4000–5000 rad by megavoltage photons in 5 weeks, and in selected cases, an additional 1500–2000 rad by electron beam boost in the tumor bed delivered over 2 additional weeks. Following surgery, 12 patients were treated sequentially with an interval of chemotherapy, radiation therapy and then the completion of chemotherapy.The added morbidity of this sequential approach is minimal: one patient of 12 had delayed primary healing of her wound, 1 of 10 patients required a break in radiation therapy because of skin erythema. Four patients were treated with intensive pre-chemotherapy radiation therapy because of inadequate surgical margins. The median time on study was 18 months from onset of treatment (range, 8–41 months). Although there have been no local, regional or distant recurrences, the follow-up time is inadequate to assess the therapeutic benefit of this combined modality treatment.     

Therapy of central nervous system leukemia in mice by liposome-entrapped 1-beta-D-arabinofuranosylcytosine

Studies were undertaken to determine the therapeutic effects of liposome-encapsulated 1-beta-D-arabinofuranosylcytosine (lip-ara-C) against intracranial L1210 leukemia. The effects of administration route, drug dosage, liposome type, and tumor load on therapeutic efficacy were also studied. One hundred % mice were cured after a single intracranial 40 mg/kg dose of lip-ara-C, dependent on tumor load. Intracranial lip-ara-C was more effective than i.v. lip-ara-C. A single i.v. dose of lip-ara-C was therapeutically superior to 5-day i.v. infusion of the free drug. Intracranial or i.v. lip-ara-C at therapeutic doses resulted in less systemic toxicity than i.v. infusion of free ara-C, suggesting possible use of lip-ara-C as an adjunct to treatment of central nervous system leukemia.     

Intraperitoneal cytostatics impair healing of experimental intestinal anastomoses.

We investigated the effect of two doses of cytostatics, administered intraperitoneally during 5 consecutive days, on the healing of ileal and colonic anastomoses constructed on the third day. The cytostatics regimen consisted of a combination of 5-fluorouracil, bleomycin and cisplatin at 10, 2 and 0.35 mg kg-1d-1, respectively, or at twice higher doses. The lower dose was similar to that given intravenously in previous experiments. Rats were sacrificed 3 or 7 days after operation. No effects of cytostatics were observed after 3 days, neither on anastomotic bursting pressure nor on hydroxyproline concentration (microgram/mg dry weight) or content (microgram cm-1). Profound effects were seen at 7 days. In the high dose group, bursting pressures in both anastomoses were greatly reduced with respect to the control group. Concurrently, collagen synthesis was severely impaired, as indicated by sustained decreased hydroxyproline concentrations and content. The lower dose of cytostatics showed essentially similar effects on hydroxyproline parameters, but affected anastomotic strength less dramatically. The data indicate that, while intraperitoneal chemotherapy may show less detrimental systemic toxicity and thus allow higher doses, its application as an adjunct to gastrointestinal surgery may be limited because of its severe effects on anastomotic repair.     

Is early post-operative treatment with 5-fluorouracil possible without affecting anastomotic strength in the intestine?

Early post-operative local or systemic administration of 5-fluorouracil (5-FU) is under investigation as a means to improve outcome after resection of intestinal malignancies. It is therefore quite important to delineate accurately its potentially negative effects on anastomotic repair. Five groups (n = 24) of rats underwent resection and anastomosis of both ileum and colon: a control group and four experimental groups receiving daily 5-FU, starting immediately after operation or after 1, 2 or 3 days. Within each group, the drug (or saline) was delivered either intraperitoneally (n = 12) or intravenously (n = 12). Animals were killed 7 days after operation and healing was assessed by measurement of anastomotic bursting pressure, breaking strength and hydroxyproline content. In all cases, 5-FU treatment from the day of operation or from day 1 significantly (P<0.025) and severely suppressed wound strength; concomitantly, the anastomotic hydroxyproline content was reduced. Depending on the location of the anastomosis and the route of 5-FU administration, even a period of 3 days between operation and first dosage seemed insufficient to prevent weakening of the anastomosis. The effects of intravenous administration, though qualitatively similar, were quantitatively less dramatic than those observed after intraperitoneal delivery. Post-operative treatment with 5-FU, if started within the first 3 days after operation, is detrimental to anastomotic strength and may compromise anastomotic integrity.     

Surgical wound healing complications in metastatic colorectal cancer patients treated with bevacizumab

BACKGROUND: Bevacizumab (Avastin; rhuMab VEGF), a humanized monoclonal antibody against vascular endothelial growth factor (VEGF), significantly prolongs survival when added to intravenous 5-fluorouracil-based chemotherapy in first-line metastatic colorectal cancer (CRC) treatment. Because antiangiogenic agents might inhibit wound healing, we assessed postoperative wound healing complications in two randomized trials of 5 mg/kg bevacizumab in CRC treatment. METHODS: We assessed the wound healing complications in patients who: (1) underwent cancer surgery 28-60 days before study treatment and (2) underwent major surgery during study treatment. Cases were reviewed for wound healing complications occurring < or = 60 days after surgery. RESULTS: With cancer surgery 28-60 days before study treatment, wound healing complications occurred in 3/230 (1.3%) bevacizumab-treated patients and 1/194 (0.5%) control patients. With major surgery during study treatment, 10/75 bevacizumab-treated patients (13%) and 1/29 control patients (3.4%) had wound healing complications. Bevacizumab-treated patients experienced complications with surgery < or = 30 and 31-60 days after the last dose. CONCLUSIONS: Bevacizumab administered in combination with 5-fluorouracil/leucovorin-based chemotherapy 28-60 days after primary cancer surgery caused no increased risk of wound healing complications compared with chemotherapy alone. While wound healing complications were increased in patients who had major surgery during bevacizumab therapy, the majority of bevacizumab-treated patients experienced no complications.     

Effect of olipifate on the wound healing proces and relapse after resection of Pliss lymphosarcoma]

The investigation was concerned with the influence of preliminary injections of Olipiphat, irrigation of operative wound and combination of both procedures on healing and relapse processes, following resection of Pliss lymphosarcoma at different stages after transplantation into rats. The physical condition of the animals after tumor resection on days 12, 10 or 7 of tumor growth was better than in controls, as a result of irrigation of the operative wound with Olipiphat or in combination with preliminary injections of the drug: they came out from anesthesia quicker, tidied themselves up and moved about the cage. Irrigation of the wound with Olipiphat or in combination with preliminary injections followed by longer survival after surgery performed at all stages of tumor growth. Moreover, one animal out of 16 in each of the 4 Olipiphat-treated groups survived 60 days recurrence-free. The drug proved more effective in stimulating the healing of larger wounds but contributed to healing by first intention in all cases.     

The effect of treatment in fractionated schedules with the combination of X-irradiation and six cytotoxic drugs on the RIF-1 tumor and normal mouse skin

RIF-1 tumors, implanted syngeneically in the gastrocnemius muscles of the right hind legs of C3H/Km mice, were treated either with X ray alone, drug alone, or drug and X ray combined. The drugs tested were bleomycin, BCNU, cis-diamminedichloro platinum, adriamycin, cyclophosphamide, and actinomycin-D. All drugs were administered either in the maximum tolerated dose or a dose that causes minimal tumor growth delay. Both drugs and X rays were administered either as a single dose or in five daily fractions. In addition to the single modality controls, seven different schedules of combined modalities were tested. Tumors were measured periodically after treatment in order that the day at which each tumor reached 4 times its initial cross-sectional area, i.e., its size at the time of treatment, could be determined. The effect of treatment on tumors was based upon excess growth delay (GD), i.e., T400% (treated)-T400% (untreated control). Treatment effects for the same combined modality schedules were also determined for normal skin, using the early skin reaction as an endpoint. Dose effect factors (DEF) were computed for all combined modality schedules and were based upon calculated radiation dose equivalents. We also calculated supra-additivity ratios, SRI and SRII, therapeutic gain factors and adjusted therapeutic gain factors. The only drugs to produce significant supra-additivity with X rays were cis-Pt and cyclo. Maximum supra-additivity for cis-Pt was afforded by divided doses of the drug (5 X 2.4 mg/kg/day) given immediately before X ray (5 X 1000 rad/day) on 5 consecutive days, although 3 other schedules also produced significant supra-additivity. Maximum supra-additivity for cyclo was seen for a single dose of 100 mg/kg followed 1 day later by a course of 5 daily X ray doses (5 X 1000 rad/day), and at least one other schedule produced almost as great an effect.     

Low-dose chemotherapy as a prelude to intensive treatment of spontaneous leukemia-lymphoma in AKR mice.

Groups of AKR mice bearing spontaneous leukemia-lymphoma were treated with five different combinations of chemotherapy or chemoradiotherapy. Each treatment combination was given in two sequences--high dose first and low dose last, or low dose first and high dose last--administered over 6-7 days. When the initial treatment was a high dose of chemotherapy, radiotherapy, or chemoradiotherapy, mortality in the first 24 hours exceeded 40%, and at least 70% of the mice in each group were dead within 2 weeks. When low-dose chemotherapy was given first, mortality in the first 24 hours was minimal but, most significantly, no deaths occurred in the 24 hours after subsequent high-dose treatment. In the most successful group (100 mg cyclophosphamide/kg on day 0, and 250 mg cyclophosphamide/kg and 400 R total-body X-irradiation on day 7), the median survival time increased significantly as compared with the median survival time among mice given the same regimen in reverse sequence (p less than 0.001) or among untreated control mice (p less than 0.01). With this regimen, survival 60 days after the last treatment was 47%. No mouse survived 30 days when the sequence of treatments was reversed. From these results, we conclude that chemotherapeutic and chemoradiotherapeutic regimens for AKR spontaneous leukemia-lymphoma should be designed so that low, minimally lethal doses precede higher doses.