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Incidence of cataracts in rhesus monkeys treated with whole-body irradiation.

The incidence of cataract formation was investigated in rhesus monkeys exposed to different doses of whole-body irradiation. Application of 850-900 rad (8.5-9 Gy) caused cataracts in 17% of the monkeys within 3 years after treatment; after 10 to 15 years, incidence increased to 100%. "Young" lenses showed a significantly lower incidence than "adult" lenses, although no differences in the stage of cataractogenesis could be demonstrated. Sex differences did not play a role in incidence and severity of cataracts. Lower doses (400 rad or 4 Gy) did not cause cataracts. In view of the close similarity between monkeys and humans, these results indicate that a single dose of 850-900 rad, sometimes employed in the treatment of acute myeloid leukemia in children, carries a strong risk of cataract development.

Animals↗

The effect of whole-body irradiation on skeletal growth in rhesus monkeys.

Late effects of single whole-body doses of 400--500 and 750--900 rads on skeletal growth in 32 rhesus monkeys were studied. Findings indicated growth inhibition strongly related to dose and age at irradiation. Doses of 750--900 rads before the age of 40 months resulted in significantly greater growth inhibition (11%) than doses given during or shortly after adolescence (p less than 0.005). Doses of less than 750 rads were not significant. In view of the close similarity between monkeys and man, irradiation of children at doses greater than 750 rads may carry a strong risk of subsequent growth retardation.

Adolescent↗

[Changes of protein metabolism following irradiation. II. Protease activity, protease pattern, protein and free amino acids in the cytoplasm and cell organelles of the rat liver following 600 R whole-body irradiation].

The protease activity of cytoplasm and cell organelles of the rat liver against liver protein and hemoglobin as a substrate increases during an initial reaction phase on the first day after 600 R whole body X-irradiation. This is probably a consequence of the degradation of cellular debris. The protein, the protease activity and the free amino acids of the cytoplasm and the cell organelles decrease during the disease phase on day 3 and 4 after irradiation. The protein loss of the liver is therefore not explained by an increased protease activity. The protease activity and the free amino acids are increased in the cytoplasm and the cell organelles during the regeneration phase of the organism between day 15 and 18 after irradiation.

Amino Acids↗

Metabolic turnover of pyridine nucleotides in ascites cells of sarcoma Sa 180 and in the liver tissue of rats before and after ionizing radiation.

Metabolic turnover of NADP+ labeled with 14C in the ribose moiety of their molecules was determined in the ascites cells of sarcoma Sa 180 and in the rat liver tissue. The half-lives of NAD+ and NADP+ in the Sa 180 sarcoma cells were 60 min (NAD+) and 90 min (NADP+) and 120 min (NADP+). Experiments were done on animals to study the time-dependent effect of ionizing radiation on the values of pooled NAD+ and NADP+ after 0.129 C/kg (500 R) and 0.387 C/kg (1500 R) whole-body irradiation, and the metabolic turnover of these nucleotides 5 h after whole-body irradiation with 0.387 C/kg (1500 R). Exposure to 0.129 C/kg (500 R) whole-body irradiation induced no apparent changes compared to the controls. Within 5 h of irradiation the whole-body dose of 0.387 C/kg (1500 R) produced changes in rat liver cells characterized by a reduction of the nucleotide biological half-lives (NAD+ from 80 to 60 min and NADP+ from 120 to 70 min). No such changes in the pyridine nucleotide turnover were detected in Sa 180 ascites sarcoma cells.

Animals↗

Enhancement by cytotoxic agents of artificial pulmonary metastasis.

The formation of lung colonies by i.v. injected Lewis lung-tumour cells in syngeneic recipients was greatly enhanced by prior treatment of the mice with cyclophosphamide. The lung-cloning efficiency was linearly related to cyclophosphamide dose and the optimum time of treatment was 2-4 days before the injection of tumour cells. The resulting lung colonies had a similar size distribution to colonies in untreated recipients. Bleomycin, local thoraric irradiation and whole-body irradiation were much less effective in enhancing the lung-cloning efficiency. Cyclophosphamide also enhanced the take probability of i.m. implanted tumour cells.

Animals↗

Transplantation of allogeneic bone marrow without graft-versus-host disease using total lymphoid irradiation.

Bone marrow (BM) and skin allografts from C57BL/Ka (H-2b/b) mice were transplanted to BALB/c (H-2d/d) recipients treated with total lymphoid irradiation (TLI), whole-body irradiation (WBI), or fractionated thymic irradiation TLI prolonged skin allograft survival about five times as long as that in untreated controls, and allowed for permanent engraftment of BM cells in approximately equal to 90% of recipients. None of the BM recipients showed clinical signs of graft-versus-host disease (GVHD) (diarrhea, weight loss, hunched back, etc.). On the other hand, recipients given WBI and allogeneic BM cells developed severe clinical GVHD. The majority of the latter recipients died within 12 days after BM transplantation, and 95% died within 61 days. Although TLI protected BALB/c mice against GVHD induced by BM cells, all recipients given TLI and allogeneic spleen cells developed lethal GVHD. Thymic irradiation alone marginally prolonged skin allograft survival, and did not allow for allogeneic BM engraftment. These results suggest that TLI may be a useful regimen in clinical BM transplantation, since this form of radiotherapy is used extensively in humans and has few severe side effects.

Animals↗

Role of alkaline endonucleases in the release of soluble chromatin from thymus, spleen and liver nuclei of normal and irradiated mice.

Thymus, spleen and liver nuclei released a large fraction of soluble chromatin in vitro when incubation was carried out in sucrose media containing low concentrations of CaCl2 and/or MgCl2. A significant fraction of deoxyribopolynucleotides (DPN) was also extracted from nuclei. After 30 min of incubation at 37 degrees C, the maximum release of soluble chromatin was observed near a pH of 8, which corresponds to the optimum pH of the alkaline endonuclease activity from thymus, spleen and liver. The soluble chromatin and DPN were precipitated by increasing the bivalent ion concentration of the medium. The protein/DNA ratio and the molecular weight of DNA suggest that the soluble chromatin and DPN represent nucleosome-like particles. The release of soluble chromatin in the first 4 hours of incubation was significantly increased if the nuclear fraction was isolated from the thymus and spleen of whole-body irradiated mice (1000 rad). This effect was absent in the liver nuclei.

Animals↗

Role of bacterial microflora in development of intestinal lesions from graft-versus-host reaction.

Acute secondary disease was induced in (C57BL X CBA)F1 mice by transplanting CBA bone marrow and spleen cells following lethal whole-body irradiation. The lesions of graft-versus-host (GvH) disease were scored quantitatively by counting of degenerated crypts in subcutaneous fetal gut implants that were free of bacteria. In conventional F1 mice the damage in F1 fetal gut was twice as great as in F1 fetal gut implants carried by decontaminated chimeras. CBA fetal gut implants developed substantial damage when present in conventional chimeras, but not when present in decontaminated chimeras. These results could be explained by assuming the presence of cross-reacting antigens on intestinal bacteria and in the gut epithelial tissue. They also explained the profound protection against delayed GvH mortality provided by removal of the intestinal microflora.

Animals↗

The effect of cyclophosphamide and other drugs on the incidence of pulmonary metastases in mice.

A study was made of the effect of various cytotoxic drugs on the ability of i.v.-injected KHT sarcoma cells to form lung colonies in syngeneic C3H mice. Some enhancement of the number of lung colonies following an i.v. injection was seen following pretreatment of the mice with actinomycin D and mithramycin, while pretreatment with vinblastine, bleomycin, methotrexate, cytosine arabinoside, or 5-fluorouracil had little or no effect on lung colony formation. Pretreatment of the mice with cyclophosphamide, however, greatly increased lung colony formation (by a factor of approximately 100). This enhancement in lung colony formation was maximal when the drug was given 24 hr prio to the injection of tumor cells, but was seen as early as 2 hr and persisted as long as 8 weeks prior to the tumor cell injection. The degree of enhancement of lung colony formation was related to the dose of cyclophosphamide and was present in weaning as well as adult mice. This enhancement was not significantly reversed by anticoagulation with either aspirin or warfarin. Immunosuppression by whole-body irradiation did not affect the number of lung colonies seen in cyclophosphamide-treated mice. The mechanism by which cyclophosphamide enhances metastatic tumor growth within the lung is not known. The major effect, however, does not appear to be mediated either by specific immunological or clotting factors.

Age Factors↗

Influence of the properties of skin allografts on the "graft survival promoting effect" of antilymphocyte serum.

Changes in the properties of non-H-2 imcompatible skin allografts, resulting from treating the graft donors with whole-body irradiation, antilymphocyte serum, cyclophosphamide, hydrocortisone, amethopterin and azathioprine, affected differently their survival in the recipients pretreated with normal and antilymphocyte serum. While in NS--pretreated recipients the modified grafts showed the tendency for a prolonged survival, in ALS-pretreated recipients they survived for a shorter time than normal allografts. In ALS-pretreated recipients, also allografts from radiation chimaeras, whose blood-forming system was of the recipient's genotype, survived worse than normal allografts and grafts from the donor syngeneic radiation chimaeras. The findings indicate that a normal physiological state of the graft is necessary for the induction and working of the protective components of the allotrasplantation reaction involved in the graft survival promoting effect of ALS. The significance of passenger leucocytes and of the functional properties of the graft, especially of the reparation cellular and extracellular processes is discussed.

Animals↗

Biological characterization of a prolonged antileukemic effect of 5-azacytidine.

A prolonged cytotoxic effect of 5-azacytidine (aza-CR) on leukemic colony-forming units (LCFU) was observed in mice with transplanted L1210 leukemia. LCFU showed rapid reaccumulation in the marrow 12 hr after injection of 0.1 mg of aza-CR per mouse. However, after 0.5 mg of aza-CR, repopulation was delayed for at least 6 days. Experiments were performed to determine the mechanism of this prolonged antileukemic effect. Suspensions of leukemic marrow prepared from mice treated 4 days previously with 0.5 mg of aza-CR were exposed to [3H]thymidine in vitro in order to kill cells in S phase. Suspensions exhibited a 40% reduction in LCFU, indicating the prolonged effect was not due to cell cycle progression delay. Mice given whole-body irradiation prior to receiving L1210 demonstrated the same delayed repopulation following the high dose of aza-CR as nonirradiated mice, suggesting that the effect was likely not due to an immune reaction. aza-CR, when given to normal mice as long as 2 days prior to leukemic transplantation, was able to prolong the survival of leukemic mice, but not when given at longer intervals. Administration of aza-CR to mice 1 day or 1 hr prior to leukemic transplantation resulted in decreased LCFU survival as well as delayed repopulation of LCFU; the rate of repopulation was not changed. This indicated a prolonged residual activity of the drug, but not sufficient to explain the total in vivo suppression. In contrast, administration of aza-CR to leukemic mice suppressed repopulation of a subsequent leukemic transplant for 4 days, even when the cells were given 2 days after the aza-CR. Cytidine was partially able to reverse the delayed repopulation of LCFU when given 1 day after aza-CR, but it was unable to reverse the phenomenon 2 days after aza-CR. Therefore, a high dose of aza-CR produces a prolonged antileukemic effect which is probably mediated by continued availability of an aza-CR metabolite. Since this effect is more pronounced in leukemic mice than in nonleukemic mice, the pharmacokinetics of high doses of aza-CR probably differ in normal and leukemic mice.

Animals↗

Experimental bacterial keratitis in neutropenic guinea pigs: polymorphonuclear leukocytes in corneal host defense.

Quantitative techniques were used to determine the relative concentrations of viable bacteria and polymorphonuclear leukocytes (PMNs) in the corneas of neutropenic and non-neutropenic guinea pigs with experimental bacterial keratitis induced with three strains of Pseudomonas aeruginosa. Neutropenia was produced by whole-body X-irradiation 1 week before infection. Significantly greater numbers of bacteria were present in the cornea of neutropenic animals 48 h after infection than were present in the corneas of non-neutropenic animals. The same was true 24 and 48 h after infecting animals with Staphylococcus aureus. Examination of histological sections showed that fewer PMNs were present in the corneas of infected neutropenic animals than in the corneas of infected non-neutropenic animals. Radiolabeling of PMNs confirmed a significant reduction in PMN concentration in the corneas of infected neutropenic animals. Tears and the corneal epithelium appear to be the most important elements protecting the cornea against local invasion by bacteria. However, once bacterial keratitis is established, PMNs play a role in limiting bacterial multiplication.

Animals↗

Collection, storage and transfusion of blood stem cells for the treatment of hemopoietic failure.

Migration of hemopoietic stem cells via the blood to sites of stem cell need is a principle that becomes established during the embryonic development of hemopoiesis and can be observed in the adult whenever bone marrow transplantations are being performed. The regular presence of stem cells in the peripheral blood lends itself to the study of their collection, storage, and use for transfusion purposes in cases of bone marrow failure. Both in dog and in man, granulocyte-macrophage progenitor cells (CFU-C) can be collected by leukapheresis from the blood in large quantities, particularly if the yield is increased by the administration of mobilizing agents such as dextran sulfate, and appear to be an indicator for the presence of stem cells. For collection and storage, a closed plastic bag system has been developed that allows the safe handling of the cells. The loss of CFU-C from freezing and thawing with DMSO as a cryoprotective agent is only 10%-20%. If frozen and thawed mononuclear leukocytes are transfused into 1200 rad whole-body X-irradiated autologous or allogeneic recipient dogs, a hemopoietic take is observed when 0.2 X 10(5) CFU-C are present among the mononuclear leukocytes (MNC). Graft-versus-host disease can be avoided in the allogeneic situation when a purified CFU-C rich cell fraction is being transfused. In man collection and storage of MNC including CFU-C is feasible and may eventually become a therapeutic tool.

Animals↗

A new method for the rapid measurement of body composition in critically ill surgical patients.

A rapid, non-invasive method for the measurement of absolute amounts of fat, protein, minerals and water in the body has been developed which is applicable to very ill patients. The patient is weighed and skinfold thickness is measured with calipers. The body contents of potassium, nitrogen, sodium, chlorine, calcium and phosphorus are measured in a whole-body radiation counter after irradiation with fast neutrons. From these values absolute amounts of body fat, protein, minerals and water are calculated. The procedure, which takes about 40 min, is carried out with the patient lying supine on a couch. The errors in the absolute measurement of the components expressed as percentages of body weight are: for fat, 4.5 per cent; for protein, 1.6 per cent; for minerals, 0.8 per cent; and for water, 4.9 per cent. The radiation dose is equivalent to that of a chest radiograph (50 mrem). We have used this technique (a) to determine the tissue composition of the weight lost in 16 patients after excision of the rectum; (b) to establish that the weight gained by 16 patients receiving intravenous nutrition was mainly water; and (c) to show that in 10 patients who received a simple solution of amino acids for 2 weeks after rectal excision body protein was preserved as efficiently as in 10 similar patients who received a full course of intravenous nutrition. This is the first time body weights of living persons have been broken down into terms of fat, protein, minerals and water, and the method should help to solve a number of metabolic and nutritional problems in clinical surgery.

Adipose Tissue↗

The sensitivity of chromatin from thymuses and spleens of irradiated mice to alkaline solutions.

Increasing amounts of DNA and proteins are released from the suspensions of chromatin from thymuses and spleens of irradiated mice (6 hours after 600R whole-body) by the action of alkaline solutions (pH 8-10) at physiological ionic strengths. The suspension of chromatin from normal tissues releases in this pH range only a small amount of proteins and negligible amount of DNA. The behaviour of liver and kidney chromatin to alkaline solutions shows no difference between normal and irradiated tissues. The time of onset and dose relation of the increased sensitivity of thymus and spleen chromatin from irradiated mice to alkaline solutions show a similar course as earlier described signs of postirradiation damage to chromatin of these tissues.

Alkalies↗

Dissolution and uptake of cadmium from dental gold solder alloy implants.

Pure metallic cadmium was irradiated by means of thermal neutrons. The irradiated cadmium (115Cd) was placed in bags of gold foil and the bags were implanted subcutaneously in the neck region of mice. Two and 3d respectively after implantation the mice were killed, the bags removed and the animals subjected to whole-body autoradiography. The autoradiograms revealed an uptake of 115Cd in liver and kidney. In another experiment specimens of a cadmium-containing dental gold solder alloy, a cadmium-free dental casting gold alloy and soldered assemblies made of these two alloys were implanted subcutaneously in the neck region of mice. The animals were killed after 6 months; cadmium analysis showed significant increases in the cadmium concentration in liver and kidney of those mice which had been given implants of gold solder alloy. The study clearly shows that due to electrochemical corrosion cadmium can be released from implants and accumulated in the kidneys and the liver.

Animals↗