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The (CBA X C57BL) F1 mice were injected intramuscularly with methylcholantrene (MCA) in a dose of 0.3 mg, and their T- and B-cells ability to cooperate in the immune response against sheep red blood cells, and also migration of these cells from the thymus and the bone marrow to the spleen were studied. The MCA immunosuppressive action proved to be associated with the inhibition of migration and cooperation of T- and B-lymphocytes in the immune response. A conclusion was drawn that the immunosuppressive effect developing during the carcinogenesis was complex and it was realized at various stages of immunogenesis.

The i.p. inoculation of C3H mice with 5 times 10-6 cells of a transplantable ovarian carcinoma invariably evokes accumulation of large amounts of ascitic fluid. Histological and pharmacotherapeutic studies indicate that obstruction to peritoneal lymphatic drainage is a key factor in the formation of carcinomatous ascites in this model. In the early stages of ascites formation, an intense inflammatory reaction appears to occlude the condusts that connect the peritoneal cavity to the subdiaphragmatic lymphatic plexus. This inflammatory reaction, elicited by the presence of tumor cells within the peritoneal cavity, can be inhibited with high-dose systemic corticosteroid therapy. Ascitic fluid accumulation in animals so treated is markedly retarded. Tumor cells do not gain access to lymphatic capillaries draining the peritoneal cavity until ascitic fluid accumulation is massive. Systemic anticoagulation with heparin or sodium warfarin does not prevent lodgment of tumor cells within these lymphatic capillaries, nor does it alter the pattern of ascitic fluid accumulation. Various considerations suggest that excess production of ascitic fluid is not a likely pathogenetic factor in murine carcinomatous ascites.

The anabolic effects of exogenous neutral protamine hagedorn insulin on tumor-bearing (TB) and non-tumor-bearing (NTB) rats were examined. Exogenous insulin (2 units/100 g/day) produced similar hypoglycemia in TB and NTB rats. Food intake and body weight gain were significantly increased by insulin in NTB rats. In TB rats in an early stage of cachexia, insulin increased food intake and host weight (total body weight minus tumor weight). In TB rats with severe cachexia, insulin increased food intake and stabilized host weight when untreated TB controls were not eating and were losing weight. When daily insulin administration was started at an early stage of tumor growth and continued until death, there was again significant enhancement of host weight and food intake. Heart and adrenal weights were significantly reduced in insulin-treated TB animals. Tumor growth was not stimulated by insulin treatment. Survival time was slightly reduced in TB rats treated with long-term insulin. Survival time in TB rats randomized to insulin during late cachectic decline was not different from untreated TB controls. Insulin did not have any measurable effect on energy expenditure or the motor activity compartment of energy expenditure in either TB or NTB rats. Insulin treatment can reverse experimental cancer cachexia. It is a nutritional therapy which preferentially feeds the host over the tumor. As yet, its beneficial effects have not prolonged survival of tumor-bearing animals.

The VX2 carcinoma produces profound hypercalcemia (17-22 mg/100 ml) in the rabbit about 3-4 wk after transplantation. A bone resorption-stimulation factor (assayed in vitro with mouse calvaria in culture) has been extracted with diethyl ether from the tumor tissue and from the medium of a clonal strain of VX2 cells grown in culture. Serologic methods reveal that the tumors contain 294 plus or minus 51 ng/g fresh weight (mean plus or minus SE, 25 tumors) of prostaglandin E2 (PGE2), a potent bone resorption-stimulating agent. VX2 cells in culture produce 0.5-3.0 mug PGE2 per mg cell protein per 24 hr. The production of bone resorption-stimulating activity and PGE2 by VX2 cells in culture were both inhibited by indomethacin (100 ng/ml). Tumors from normocalcemic, indomethacin-treated rabbits (10-40 mg/rabbit/24 hr) contained little or no bone resorption-stimulating activity nor PGE2. Tumor-bearing rabbits receiving indomethacin continuously did not develop hypercalcemia, however, following cessation of indomethacin administration, hypercalcemia developed rapidly and was again reversed by reinstitution of indomethacin feeding. In untreated, hypercalcemic, tumor-bearing rabbits, initiation of indomethacin treatment was followed by a rapid return of the plasma calcium to the normal range. Systemic venous plasma from hypercalcemic tumor-bearing plasma contained higher concentrations of PGE2 than plasma from normocalcemic control rabbits. Venous drainage of the tumor contained even higher plasma PGE2 concentrations than systemic venous plasma in hypercalcemic animals; plasma PGE2 concentrations locally and in systemic plasma were unmeasurable (less than 70 pg/ml) in normocalcemic, indomethacin-treated, tumor-bearing rabbits. We conclude that PGE2 is a bone resorption-stimulating factor produced by VX2 tumor cells, and that secretion of PGE2 by the tumor in vivo may well be responsible for the hypercalcemia observed in tumor-bearing rabbits.

The morphologic characteristics of a scar may render it an "immunologically privileged site" providing fertile ground for tumor occurrence and growth. We sought to extend this concept and to determine the effect of different stages of wound healing on tumor occurrence. Syngeneic strain-2 guinea pigs and a methylcholanthrene-induced liposarcoma (MCA-2) were used. Incisional flank wounds were created at appropriate intervals such that at the time of tumor inoculation each group of animals had a sequentially aged wound which was a) acute, b) three weeks old, c) nine weeks old, d) 11 weeks old, e) created one week after tumor injection, or f) no wound. Wounds which were three, nine, or 11 weeks old consistently caused a significant increase in tumor growth rate following inoculation of a single cell tumor suspension (<.001). The delayed wounds, or those created following after tumor injection, and the acute wounds did not promote increased tumor growth. This study demonstrates that the ability of a wound to amplify or retard tumor growth may vary with its age. As a postulate we suggest that the relative paucity of lymphatic regeneration within scar tissue may render it an "immunologically privileged site" such that early recognition and destruction of tumor cells within the scar may be delayed long enough for the tumor to grow to a "critical size." Subsequent to this regardless of the host's immunocompetence the tumor can no longer be destroyed by an immune mechanism. The general lack of progressive growth of tumor cells placed in acute wounds suggests that they were not protected from immunocompetent cells and were destroyed by the ongoing inflammatory response to injury. Therefore, different biologic characteristics of a surgical scar are important in potentiating or retarding tumor growth. Variations in such factors may account for the local recurrence of cancer in operative wounds.

Plasma concentrations of ammonia were elevated significantly in tumor-bearing rats prior to the onset of anorexia and continued to increase as the tumor grew and anorexia developed. Associated with this hyperammonemia were elevated levels of brain glutamine and large neutral amino acids (phenylalanine, tyrosine, tryptophan, methionine, histidine). Concentrations of the dopamine metabolites, DOPAC or HVA were elevated in the corpus striatum, nucleus accumbens, hypothalamus and amygdala of anorectic tumor-bearing rats only, while levels of the serotonin metabolite, 5-HIAA, were increased in these brain regions in both anorectic and non-anorectic tumor-bearing rats. Infusing ammonium salts into non-tumor-bearing rats elicited anorexia and alterations in brain amino acid profile and neurotransmitter metabolism that were similar to those observed in anorectic tumor-bearing rats. Therefore, we conclude that ammonia released by tumor tissue may have a direct role in the etiology of experimental cancer anorexia.

In the cells of RS-1 carcinoma and those of Iensen's sarcoma it has been stated that acceleration and inhibition of tumor growth induced by nonspecific influence (vitamin A, hydrocortisone, proserin) are accompanied by uniform morphological changes of intracellular structures. Therefore, it is possible to suggest that the changes observed reflect a certain cell adaptation to the altering environmental conditions (cell stress-reaction). The cell stress-reaction is presented morphologically and hence, can by systematized. An attempt of such systematization is suggested.

Sendai virus (SV), mouse hepatitis virus (MHV), and pneumonia virus of mice (PVM) are common viral infections of mice. Influence of these viral infections on the prevalence of liver tumors, lung tumors, and lymphoma is of concern in chemical carcinogenicity studies. Body weight, survival, and tumor prevalence of B6C3F1 mice with and without viral infections in 33 male and 34 female untreated control groups and 32 male and 32 female low- and high-dose groups of 2-year chemical carcinogenicity studies were evaluated. In male mice, the SV infection was associated with significantly (p less than 0.05) higher survival of control, low-dose, and high-dose groups, and higher prevalence of liver tumors and lymphoma. The increases in tumor prevalence are possibly due to an increase in the survival of male mice that had SV infection. However, when interlaboratory variability and time-related effects were taken into account, the number of significant effects was consistent with the expected false-positive rate inherent to the statistical procedures. The MHV and PVM infections did not cause consistent changes in body weight, survival, and tumor prevalences in the control and chemical treatment groups of male mice. Viral infections did not cause consistent increases or decreases in body weight, survival, or tumor prevalence in the control and chemical treatment groups of female B6C3F1 mice.

Peritumoral brain edema was produced by intracerebral transplantation of Walker 256 tumor in rats. Local cerebral blood flow (LCBF), local cerebral glucose utilization (LCGU), and capillary permeability were studied in untreated and methylprednisolone-treated rats by quantitative autoradiography. In the untreated group, LCBF and LCGU were widely depressed in the cortex and deep structures of the hemisphere ipsilateral to the tumor. In the methylprednisolone-treated animals, LCBF and LCGU were significantly better than in the untreated animals. Capillary permeability was highly increased in the viable part of the tumor in the untreated animals. In the methylprednisolone-treated group, capillary permeability of the tumor was significantly lower than that in the untreated group. These results may suggest that increase in capillary permeability of the tumor is the major source for edema fluid production, and that methylprednisolone improves brain edema by decreasing capillary permeability of the tumor. Decrease in edema fluid formation may result in restoration of blood flow and glucose metabolism in the adjacent brain tissue, and may improve clinical symptoms and signs.

The effect of iron deficiency on tumour growth and on host survival was studied in BALB/c mice with transplanted Merwin Plasma Cell-II tumors. Iron deficiency was induced by maintaining the animals on an iron-free diet consisting of milk-cornflour supplemented with CuCl2 and vitamins A and D. Iron deficiency resulted in retardation of both body and tumor growth in weanling BALB/c mice. Their survival, however, was not significantly different from that of iron supplemented controls. The inhibitory effect of iron deficiency on host and tumour growth could not be reproduced in adult BALB/c mice. The survival of tumor-bearing hosts maintained on a milk-cornflour diet (whether supplemented with iron or not) was significantly longer than that of animals maintained on a purina diet.

This study addressed the question of whether hypercorticism in tumor-bearing animals contributes to the wasting of body fat and lean body mass, particularly that of skeletal muscles. For this purpose, hydrocortisone-substituted nongrowing sarcoma-bearing and control C57BL/6J mice were used that were either adrenalectomized or sham-operated prior to experimentation. Adrenalectomy in itself did not alter food intake or body composition in normal animals. Tumor-bearing mice and pair-weighted control animals had elevated urinary excretion of corticosteroids compared with the urinary excretion in freely fed controls. The malignant tumor induced the well-recognized wasting in tumor-bearing animals, irrespective of the presence of the adrenal glands. Therefore, an elevated corticosteroid production did not account for the wasting of body fat, lean body mass, skeletal muscle proteins, or decreased RNA activity in quadriceps muscles from tumor-bearing animals, although such muscles were sensitive to physiologic doses of injected hydrocortisone (20 micrograms/day). Tyrosine aminotransferase (TAT) activity in liver tissue from tumor-bearing animals was higher than that induced by pharmacologic doses of hydrocortisone in normal animals. Physiologic doses of hydrocortisone induced hepatic TAT activity, but pair-weighed control animals with the same degree of hypercorticism as was found in tumor-bearing animals had normal TAT activity in liver tissue. Although hypercorticism is present in tumor-bearing animals, the results demonstrate that cancer cachexia can start and proceed independently of the adrenal glands. Therefore, adrenal hyperfunction is not the proximate cause for the development of experimental cancer cachexia induced by anorexia.

The action of local laser-induced microvascular injury on the frequency of tumour-cell lodgement and on the ability of these cells to migrate out of the microvessel lumen was studied. Intravital TV-microscope with a videotape recorder and an ultra-voilet laser was used. Ascites Saidel hepatoma cells were injected into the blood stream of rats. Lodgement of tumour cells in the mesenteric vessels was observed but rarely (11%). The lodged cells adhered to the microvascular wall and gradually migrated from the lumen. The injury of the wall with laser beam results in the formation of microthrombi and in increase in the frequency of lodgement of the tumour cells in these vessels: 82% against 11%, but migration of these cells decreased. The data obtained supported the significance of the microthrombus formation in the metastatic process. However, this role is not one-sided since on the background of increased frequency of adhesion of the tumour cells there was noted a decrease in their motility in the course of several hours after the lodgement in the microvessels.

The types of anemia associated with natural and experimental feline leukemia virus (FeLV) infection in cats were investigated. In one experiment, 10 kittens were inoculated neonatally with Jarrett FeLV-1, an isolate of subgroup A; 6 developed anemia a few weeks later. This anemia was characterized by macrocytosis, normoblastosis, increased erythropoiesis in the bone marrow, and extramedullary hematopoiesis in the spleen. Anemia was transient and nonfatal and occurred before the onset of lympoid malignancy. The same type of anemia was also seen in 9 of 24 kittens inoculated with Jarrett FeLV-9 of subgroups A and B. A different form of anemai occurred in another experiment in which 10 kittens were inoculated with FeLV-C of subgroup C only. All 10 kittens developed a profound aplastic or erythroblastopenic anemia in which the bone marrow became depleted of erythroid tissue; all kittens died within 16 weeks, most as a direct result of anemia. In an experiment in which kittens were inoculated with FeLV-B of subgroup B only, no kitten showed anemia. Cats with naturally acquired, nonleukemic lymphosarcoma were also studied. Of 33 lymphosarcomas in which myelophthisis was excluded as a cause, 54% of the affected cats had anemia, the features of which were consistent with hemolytic origin. When virus could be grown from these lymphosarcomas, it was of subgroup A alone or a combination of A and B. With one exception, anemic cats had low or negative titers to feline oncornavirus-associated cell membrane antigens. Until more isolates have been tested, it is not known if the various hematologic changes reflected differences in the pathogenic effects of the subgroups of the virus or of types of strains within them.

Growth of syngeneic P815 mastocytoma in DBA/2J male mice was evaluated as a result of various stress regimens. A single session of inescapable shock resulted in earlier tumor appearance, exaggeration of tumor size, and decreased survival time in recipient animals. Escapable shock had no such effects. The effects of the inescapable shock were mitigated if mice received long-term shock treatment.

Divided doses of 6,000 or 8,000 rad of X-ray were given to the gastric region of ICR/JCL female mice with immune atrophic gastritis produced by the injection with allogenic stomach antigen. The carcinogenic effect of X-rays for inducing gastric carcinoma was significantly increased by this method. Two points can be presented as its reason. First, the pyloric gland mucosa regenerating from injuries by immunization was exposed to the divided dose of X-rays. Second, the marked requirement of gastrin secretion attributable to severe injuries of parietal cell mass by immunization and local X-irradiation acted as a promoting factor on the induction of gastric carcinoma by X-ray for a long time through the trophic effects on the pyloric gland.

These studies examined the fate of Factor XIII (fibrin-stabilizing factor) in mice with plasmacytoma (MOPC-300, MOPC-384, MOPC-467, and J-558). Plasma Factor XIII levels in these mice decreased progressively with tumor expansion. No plasma inhibitors of Factor XIII activity could be detected. Factor XIII was found on plasmacytoma cell membranes and in the cytoplasm of the malignant cells by immunofluorescence. The inverse relationship between tumor load and plasma Factor XIII levels suggested that the fibrin-stabilizing factor was absorbed by the malignant cells.

Infection with herpes simplex virus (HSV) enhances the growth of Lewis lung tumor (LLT). Infection with HSV-1 enhances as efficiently as HSV-2. A significant acceleration of primary tumor formation was obtained. In mice, lung metastases were increased in number and size above the controls. Enhancement occurred only with high doses of infectious virus and was also obtained only when the virus infection was at a site close to that of the tumor implantation. This finding, in addition to the lack of antigenicity of LLT, is interpreted as arguing against an immunologic mechanism of the phenomenon.

Cancer patients have the highest prevalence of malnutrition of any group of hospitalized patients. The potential causes of this malnutrition are numerous, as elements of both starvation and stress are evident in the cancer-bearing host. The presence of the tumor alone may lead to reduced intake of nutrients and treatment modalities of surgery, chemotherapy, and radiation therapy further exacerbate nutritional deficits. It is clear that the tumor requires energy substrates to grow, and that these substrates are exacted from the host. Animal studies identify progressive nutritional depletion concomitant with increasing tumor growth during ingestion of a regular diet. This appears predominantly due to reduced dietary intake in addition to host metabolic alterations. In animal/tumor models deliberate dietary protein depletion results in severe host weight loss, but also causes diminished tumor growth rates. Dietary manipulation in these animal/tumor models have demonstrated methods of improving tumor response to chemotherapy by manipulation of tumor growth rates. In addition, drug-pharmacokinetics have been altered by dietary manipulation. However, data from animal/tumor models are not directly applicable to man since the tumor in animals usually results in the death of the host within six to eight weeks. Nevertheless, controlled laboratory studies in animals provide basic metabolic information which promotes understanding of host/tumor relationships in man. In cancer patients malnutrition has prognostic value, leads to a distortion of body composition with erosion of body protein and fat stores, and compromises the delivery of adequate therapy. There is no direct objective evidence of accelerated tumor growth in humans with cancer who receive nutritional support as part of their treatment regimen. The host benefits to the extent that body composition is at least maintained during the period of nutritional repletion. Thus, nutritional support provides support to the patient during periods of treatment and dietary deprivation. No improvement in the tumor's response to therapy, however, has been demonstrated by this approach.

Prostaglandin biosynthesis and metabolism were studied in the VX2 carcinoma-bearing rabbit, an animal model of prostaglandin-mediated hypercalcemia. All the identification and quantification of the prostaglandins were done by gas chromatography-mass spectrometry. The tumor incubated in vitro converted exogeneous arachidonic acid principally to PGE2. Biosynthesis from endogenous precursor lipids yields mainly PGE2 and PGF2alpha. The 100,000 x g supernatant fluid of the tumor did not contain any metabolizing enzymes. Significant hypercalcemia developed between the first and second week after tumor implantation. The levels of the major plasma metabolite of PGE2, 15-keto-13,14-dihydro-PGE2, became elevated at one week, had risen 25-fold by the end of the second week, and at the fourth week were elevated to 256 times the pre-incubation levels. The concentration of 15-keto-13,14-dihydro-PGF2alpha in plasma rose in parallell but to a lesser degree. 7alpha-hydroxy-5,11-diketotetranor-prostane-1,16-dioic acid, the major urinary metabolite of the E prostaglandins, was elevated two weeks after tumor implantation and rose until the fifth week. Indomethacin treatment lowered both serum calcium and the plasma level of 15-keto-13,14-dihydro-PGE2.

The relation of congenital malformations to tumor development was examined. Pregnant Sprague-Dawley rats were given 200 rads of X-rays on the 15th or 16th day of gestation and injections of 10 mg ethylnitrosourea (ENU)/kg 1-4 days later, or they were irradiated or injected only. Surviving weanlings that had been irradiated had micrencephaly and other malformations. Offspring exposed to ENU only had no external deformities. By 15 months of age 16.7% of the offspring exposed to X-rays and ENU prenatally had developed neurogenic tumors, whereas 62.2% of those exposed to ENU alone had developed tumors. Those only irradiated had no tumors. Both of the former groups developed oligodendrogliomas, mixed gliomas, ependymomas, and schwannomas, but the first manifestations of tumors occurred later in the group receiving the combined treatment. This delay persisted furing the subsequent period of the study.

We have studied the induction of a granulocyte-associated leukocytosis (leukemoid reaction) in C3HA, C57B1/6, and DBA/2 mice by a number of transplantable tumors of different origin. Leukemia L1210, Hepatoma 22, a transplantable mammary carcinoma of spontaneous C3HA origin, and a L929 culture fibroblasts-derived rhabdomyosarcoma, all induced a leukemoid reaction in their specific mouse strain. Melanoma B16 and Lewis lung carcinoma gave no reaction; Adenocarcinoma 755 and Harding-Passey melanoma evoked a leukocytosis but not due to an increase in neutrophils. Some extratumoral factors can influence the hematological response; the intensity of final leukemoid reaction was higher in female mice than in males bearing the same tumor. On the other hand, Ehrlich ascites tumor transplanted in all three inbred mouse strains rendered different levels of leukemoid reaction; response was higher in DBA/2, intermediate in C3HA and lower in C57B1/6.

Walker carcinoma 256/B transplanted sc in CD-COBS rats induce a decrease of food intake when the tumor size is less than 5% of the body weight. This anorexia is accompanied by a decrease of the adipose tissue and, to a lesser extent, of muscular tissue. The mechanism involved in cancer-induced anorexia seems to be different from that of classic centrally acting anorectic agents. Among the drugs tested to counteract this anorexia only cyproheptadine shows a modest effect. Cyclophosphamide reduces tumor growth and prevents decrease in food intake. It is suggested that Walker carcinoma 256/B may be a useful animal model to study problems related to cancer-induced anorexia and cachexia.

This study was designed to elucidate the effect of ethane-1-hydroxy-1,1-diphosphonate (EHDP) in experimental rodent tumors. EHDP had no antitumor activity against the L1210 leukemia implanted i.p. and against sarcoma 180, Lewis lung carcinoma (3LL) and Walker 256/B carcinoma injected i.p., s.c. or i.m. respectively. EHDP did not interfere with the antitumor activity of commonly used conventional chemotherapeutic agents (adriamycin, cyclophosphamide, 5-fluorouracil, bis-chloroethylnitrosourea) in the L1210 and 3LL models. EHDP reduced proportionally to the dose the hypercalcemia and hypercalciuria due to the Walker 256/B carcinoma growth. In an effort to evaluate whether EHDP-treated osseous tissues were more refractory to tumor growth, cells from sarcoma 180 and 3LL carcinoma were implanted intratibially (i.t.). Growth of 3LL cells was not consistently affected by EHDP, whereas a modest, but significant, growth inhibition was consistently observed with sarcoma 180 injected i.t. Growth of sarcoma 180 implanted i.p. or s.c. was not reduced by this drug, thus suggesting that inhibition of i.t. sarcoma 180 was in fact related to alterations of osseous tissues by EHDP. Inoculation of Walker 256/B carcinoma intra-aortically resulted in osteolytic bone lesions in the hind limbs. EHDP inhibited the formation of bone metastasis under these conditions.

Gluconeogenesis, when sharply stimulated by exhaustion of the liver glycogen reserves, is one of the factors maintaining the normal blood sugar level in mice with tumors. Hyperglycemia induce by glucose leads to an increase in the liver glycogen content and a decrease in the intensity of gluconeogenesis in control mice with tumors. Only in the latter, however, does glycogen synthesis from noncarbohydrate compounds rise again steadily after the injections of glucose are discontinued.

This report summarizes the data from two animal and cell culture systems that serve as models that show how certain malignant tumors produce hypercalcemia by means of a humoral mechanism. Studies with the HSDM1 murine fibrosarcoma and the VX2 carcinoma in the rabbit have led to the conclusion that these two tumors produce hypercalcemia in the host by means of a mechanism that utilizes prostaglandin E2 as the mediator between the neoplasm and bone. Analogous or identical mechanisms may operate in a small number of human tumors.

Although many patients with humoral hypercalcemia of malignancy exhibit reduced serum 1,25-dihydroxyvitamin D [1,25-(OH)2D] levels, N-terminal fragments of recently identified PTH-related protein as well as PTH itself elevate serum 1,25-(OH)2D concentrations. In the present study, the effect of tumor extracts from human tumor-implanted hypercalcemic nude rat models with high and low serum 1,25-(OH)2D on renal 1,25-(OH)2D3 production was examined using rat kidney cells in culture. Whereas tumors from rats with high serum 1,25-(OH)2D levels (OCC rats) contained only a single peak of cAMP production-stimulating activity (CPSA) in osteogenic sarcoma cells on reverse phase HPLC, tumor extracts from rats with low serum 1,25-(OH)2D levels (UCC rats) contained at least two peaks of CPSA. The main peak (peak A) was estimated to be approximately 17K by gel permeation chromatography, which was the same as the molecular size of the hitherto identified PTH-related protein, and a minor peak of CPSA (peak B) was estimated to be about 25K. When peak A or crude extracts of OCC tumors as well as human PTH-(1-34) were added to primary cultures of rat kidney cells, the production of 1,25-(OH)2D3 was significantly stimulated. In contrast, although peak B or crude UCC tumor extracts had no effect on 1,25-(OH)2D3 production in themselves, when they were added together with peak A or human PTH-(1-34) the stimulation of 1,25-(OH)2D3 production was almost completely inhibited. Both peak A and peak B enhanced cAMP production in cultured kidney cells, and the cAMP production by peak A was not affected by peak B. These results are consistent with the possibility that elaboration of an additional factor from tumor cells may be the mechanism by which serum 1,25-(OH)2D levels are suppressed in patients with humoral hypercalcemia of malignancy. The nature as well as the mechanism of action of this factor remain to be elucidated.

In New Zealand white rabbits bearing the transplantable VX2 carcinoma intramuscularly in the hind limbs uniformly a granulocytosis syndrome developed, characterized by peripheral blood neutrophilia and marked granulocytic bone marrow hyperplasia, whereas the syndrome did not always develop in animals bearing the tumor intraabdominally. The relationship between the extent of pulmonary metastases and granulocytosis/bone marrow hyperplasia was significant (P less than 0.005). This positive correlation (correlation coefficient = 0.85) existed for both animals bearing intraabdominal tumors and animals bearing intramuscular tumors. The granulocytic syndrome occasionally occurred in rabbits with mild degrees of pulmonary metastatic involvement, but never with total absence of pulmonary metastases. Hypercalcemia occurred prior to the appearance of pulmonary metastases and was not essential to the development of granulocytosis. These data suggest that granulocytosis in VX2 carcinoma-bearing rabbits is dependent on the presence of tumor in the lungs and is not directly related to implantation site. This tumor-bearing animal model may be suitable for studies of tumor-associated granulocytosis in vivo.

Rabbits were injected with VX2 cancer cells into the left thigh or tibia, and given indomethacin 1-16 mg/kg daily starting on the day before tumour implantation or 7, 14 or 21 days after implantation. Indomethacin at 2 mg/kg and above from before tumour implantation reduced osteoclast proliferation and the amount of prostaglandin-like material extracted from homogenates of excised tumours, but the inhibition of bone destruction in vivo was significant only with indomethacin at 4 mg/kg and above. Indomethacin at 8 mg/kg reduced osteoclast proliferation and bone destruction, but the effect was statistically significant only when given within 7 days of inoculation with the tumour. The place of indomethacin and other inhibitors of prostaglandin synthesis has not yet been established in the management of patients with skeletal metastases. Drug administration might need to be started at the time of diagnosis and removal of the primary tumour, rather than when skeletal metastases are evident.

Evidence is presented that a tumor-derived transforming growth factor is responsible for stimulating bone resorption and causing hypercalcemia in an animal tumor model of the hypercalcemia of malignancy. Both conditioned medium harvested from cultured tumor cells and tumor extracts of the transplantable rat Leydig cell tumor associated with hypercalcemia contained a macromolecular bone resorbing factor with the chemical characteristics of a tumor-derived transforming growth factor.

The effects of protease inhibitors(PI), t-AMCHA, gabexate, aprotinin and heparin on the growth of mouse MM2 ascites tumor (MAT) and on several components of fibrinolysis were studied. The drugs were administered intraperitoneally one time daily for 12 days, one day after the tumor transplant. The volumes of ascites, total packed cell volume (TPCV) and fibrinolytic parameters (FDP, whole plasmin, plasminogen activator (PA)) were measured on the 8, 10 and 12th days of therapy. Fibrinolytic activity was assayed by the lysin sepharose affinity chromatography-radio caseinolytic method. Fibrinolytic activity in the ascites increased during the tumor growth. The ascites accumulation as well as levels of FDP, whole plasmin and PA in the drug treated group were significantly decreased when compared to the control group. In these drug-treated groups, MAT cells agglutinated in the abdominal cavity, but in contrast to this, no agglutination was observed in the control group. It was uncertain whether PI directly inhibited tumor growth. The fact that PI inhibited the ascites accumulation and also decreased fibrinolytic activity suggest the involvement of protease in the neoplastic process and indicates another therapeutic approach to malignant ascites tumors.

It is concluded that endolymphatic infusion of X-ray contrast substance in the presence of migrating tumor cells in lymphatic routes is inherent in a potential danger of tumor dissemination. Although getting of tumor cells in blood does not always result in metastases, nevertheless, a due account should be taken of the fact that lymphography is frequently performed in poor immunological resistance patients, preliminarily subjected to chemo- and radiotherapy. The decrease of immune resistance of the organism, in which the lymphatic system is of primary importance, is known to contribute per se to generalization of the tumor process. Another important conclusion is that the principal mass of tumor cells is ejected in the immediate period after endolymphatic injection of X-ray contrast substance. Thus, the cannulation of the thoracic duct during this period may prevent or reduce getting of massive amounts of tumor cells into the total blood flow.

The studies presented herein were done to investigate the effects of drug-induced hypocholesterolemia and chronic hormonal stimulation on cholesterol metabolism and steroid biosynthesis in a functional Leydig cell tumor. It was found that 4-aminopyrazolo(3,4-d)-pyrimidine (4-APP)-induced hypocholesterolemia had no effect on a) the amount of cholesterol present in the tumor, b) cholesterol biosynthesis, and c) steroid production. Chronic stimulation with choriogonadotropin also had no effect on the amount of cholesterol present in the tumor, but it increased steroid production and cholesterol biosynthesis. These results suggest that the Leydig tumor cells primarily use intracellular cholesterol for steroid biosynthesis. Other data show that 4-APP treatment reduces gonadotropin binding in the Leydig tumor cells.