Biomedical subjects

P J Bugelski

Publications and source records attributed to P J Bugelski.

70 records · Page 4Linked to original sources

PubMed1988

Modulation of rat bronchoalveolar lavage cell function by the intratracheal delivery of interferon-gamma.

To determine if there is a rationale for compartmentalized immunostimulation, we have carried out a series of experiments to evaluate whether intratracheal delivery of interferon-gamma (rRatIFN-gamma) can activate rat bronchoalveolar lavage cells (BAL) for in vitro expression of tumoricidal activity against xenogeneic P815 tumor cells and enhanced in vitro microbicidal activity against the intracellular protozoan Toxoplasma gondii. Treatment of rat alveolar macrophages in vitro activates them for both of these activities as well as enhanced production of superoxide anion. We found that a single intratracheal dose of 5,000-10,000 units of rRatIFN-gamma activated rat BAL for both microbicidal and tumoricidal activity. To determine the duration of activation, microbicidal activity was determined 1, 2, 3, 5, and 7 days after a single intratracheal dose of 5,000 units of IFN. Enhanced microbicidal activity was maintained through day 3 but returned to control levels by day 5. Alveolar macrophages always accounted for the majority of cells in the lavage populations. However, intratracheal IFN caused an increase in the number of polymorphonuclear leukocytes and lymphocytes in the lavageable cells and, although these cells were always in the minority, they may have contributed to both the tumoricidal and microbicidal activity of the lavage cells. These studies demonstrate that local administration of an immunostimulant can activate pulmonary defense cells and may be a feasible route of drug delivery for prophylaxis against pulmonary infections.

Animals↗

PubMed1988

Temporal relation between neutrophil accumulation and myocardial reperfusion injury.

Infiltration of polymorphonuclear leukocytes (PMN) is associated with the progression of myocardial infarction and reperfusion injury. However, little is known about the time course of cellular infiltration. To investigate this issue, rats were subjected to 30 min of coronary artery occlusion followed by reperfusion for less than or equal to 96 h. Myocardial injury was determined by measuring the depletion of myocardial creatine phosphokinase activity, and PMN infiltration was assessed by measuring myeloperoxidase (MPO) activity. MPO activity increased from 0.7 U/g tissue in non-operated animals, to a peak of 6.7 +/- 0.8 and 6.4 +/- 1.4 U/g at 6 and 24 h after coronary artery reperfusion, respectively. MPO activity decreased to 3.3 +/- 0.8 U/g at 48 h and 1.1 +/- 0.4 U/g at 96 h, suggesting diminished PMN accumulation. Histological examination confirmed the accumulation and resolution of PMN over the 96-h period. At 24 h, there was a significant linear correlation between infarct size and MPO activity, whereas at 96 h no relationship was found. These data indicate that PMN infiltration occurs early in response to reperfusion injury and persists for only 24 h after initiation of reperfusion. These findings suggest that attempts to moderate inflammatory cell responses to myocardial injury should be administered early after coronary artery reperfusion to limit the accumulation of potentially deleterious inflammatory cells.

Animals↗

PubMed1988

Influence of selective endoperoxide/thromboxane A2 receptor antagonism with sulotroban on lysis time and reocclusion rate after tissue plasminogen activator-induced coronary thrombolysis in the dog.

The purpose of this investigation was to examine the potential beneficial effect of the selective endoperoxide/thromboxane A2 (TxA2) receptor antagonist, sulotroban (BM 13.177), on tissue type plasminogen activator (tPA)-induced coronary thrombolysis in the dog. A stenosis that eliminated reactive hyperemic capacity was placed on the circumflex coronary artery and an occlusive thrombus was produced by electrical injury to the intimal surface of the artery. Upon occlusion, sodium heparin was administered (300 U/kg i.v.) followed by 100 U/kg i.v. every hour thereafter. All dogs received i.v. tPA 60 min after the formation of the occlusive thrombus at a dose of 10 micrograms/kg/min for up to 90 min, if necessary, to elicit reperfusion. Thrombolysis was demonstrated in all dogs by restoration of coronary blood flow. Dogs were randomized to one of three groups. Group I consisted of 24 animals that received vehicle infusion along with tPA. Group II consisted of 10 animals that received sulotroban at a bolus dose of 1 mg/kg i.v. followed by 1 mg/kg/hr i.v. administered simultaneously with tPA. Group III consisted of 11 animals that received sulotroban at a bolus of 10 mg/kg i.v. followed by 10 mg/kg/hr i.v. administered simultaneously with tPA. Infusions of either vehicle or sulotroban were continued for 2 hr, post-thrombolysis. tPA was infused for at least 30 min, after which infusion of tPA was terminated upon achieving a reperfusion level of coronary blood flow equivalent to 50% or greater than control blood flow. All animals occluded spontaneously to electrolytic stimulation between 32 and 62 min. tPA-induced thrombolysis occurred in Group I vehicle-infused animals at 32 +/- 5 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

The mechanism of acute cytotoxicity of triethylphosphine gold(I) complexes. I. Characterization of triethylphosphine gold chloride-induced biochemical and morphological changes in isolated hepatocytes.

Triethylphosphine gold complexes are effective therapeutic agents used for the treatment of rheumatoid arthritis. Many of those molecules are also highly cytotoxic in vitro and can inhibit DNA and protein synthesis. Preliminary experiments have indicated that triethylphosphine gold chloride (TEPAu) may induce the peroxidative decomposition of cellular membrane lipids. The purpose of these investigations therefore was to evaluate the role of lipid peroxidation in the mechanism of acute cytotoxicity of a gold(I) coordination complex, TEPAu, and to examine the early morphological and biochemical changes induced by TEPAu in suspensions of freshly isolated rat hepatocytes. TEPAu caused a rapid loss of cell viability at concentrations above 25 microM which was significantly different from that of control by 60 min and complete by 180 min of incubation. TEPAu also depleted cells of reduced glutathione (GSH) and increased the formation of malondialdehyde (MDA) by 60 min. Incubation of cells with either of the antioxidants, N,N'-diphenyl-p-phenylenediamine (DPPD) or promethazine blocked the formation of MDA but did not alter the time course of cell death or GSH depletion induced by TEPAu. TEPAu also caused a decrease in cellular NADPH and NADH by 10 min. Electron microscopy of hepatocytes exposed to TEPAu revealed early (5 min) formation of flocculent electron-dense precipitates within condensed mitochondria. These changes characteristically preceded cell death. Energy-dispersive electron-probe microanalysis indicated that the electron-dense precipitates did not contain detectable amounts of gold. TEPAu also caused a concentration-dependent decrease in cellular ATP and oxygen consumption in isolated rat hepatocytes. These data suggest that lipid peroxidation, as indicated by the formation of MDA, is probably not a major mechanism by which triethylphosphine gold complexes lethally injure cells. These data, therefore, suggest that mitochondria may be target organelles in TEPAu-induced toxicity to isolated rat hepatocytes.

Animals↗

PubMed1987

Macrophage content of spontaneous metastases at different stages of growth.

The macrophage content of spontaneous metastases has been quantified morphometrically for a panel of rodent tumors at different stages of metastatic tumor growth. Using a histochemical technique to selectively stain macrophages, we have evaluated the relative content of macrophages in spontaneous pulmonary metastases from the 13762NF MTLn3 rat mammary adenocarcinoma and the B16-BL6 mouse melanoma, as well as in spontaneous hepatic metastases from the M5076 mouse reticulum cell sarcoma and from autochthonous reticulum cell sarcomas in SJL/J mice. Between 112 and 254 separate, individual metastases were evaluated for each of these tumors. The data show that the relative macrophage content of very small metastases is high. However, as metastases grow the relative macrophage content falls, reaching uniformly low levels by the time the metastases are 0.5 mm in diameter. These data are very similar to our previous observations on experimental metastases where the same pattern of high macrophage content in small metastases was seen. Finding the same pattern in more slowly growing, spontaneous metastases of tumors derived from several different tissues and in two species suggests that the fall in relative macrophage content is not a phenomenon isolated to experimental metastases, a particular site, or a tissue of origin for the tumor. The relative decrease in macrophage content may thus be a general phenomenon with important implications for immunotherapy directed to enhancing the tumoricidal activity of macrophages.

Adenocarcinoma↗

PubMed1987

Activation of rat alveolar macrophages by gamma interferon to inhibit Toxoplasma gondii in vitro.

We have investigated the effects of murine interferons on the ability of rat alveolar macrophages (AM) to inhibit the proliferation of the intracellular protozoan Toxoplasma gondii. This activity was determined by measuring suppression of 3H-uracil uptake into the Toxoplasma and by microscopic enumeration of the intracellular organisms. Recombinant gamma interferon (rMulFN-gamma), but not alpha/beta interferon (IFN-alpha/beta) was able to activate AM for antimicrobial activity in vitro. Maximum activation was achieved by incubation with 50-200 units/ml rMulFN-gamma and the activity was lost at one unit/ml. The highest levels of activation were obtained when macrophages were incubated with interferon for 48-72 h prior to the challenge with Toxoplasma organisms. Activation could still be obtained, however, when the interferon was added to the cultures as late as 2 h after the phagocytosis of Toxoplasma. Neither MDP nor low concentrations (1-1-ng/ml) of S. typhosa lipopolysaccharide (LPS) were able to activate these cells to inhibit the growth of Toxoplasma. Phagocytosis of Toxoplasma by AM did not result in the release of O2-, in fact the spontaneous release of O2- by these cells was inhibited by Toxoplasma. This inhibition was reversed by preincubation of the cells with rMulFN-gamma.

Acetylmuramyl-Alanyl-Isoglutamine↗

PubMed1987

Recruitment of exogenous macrophages into metastases at different stages of tumor growth.

The endogenous tumor-associated macrophage content and recruitment of labeled peritoneal exudate cells into experimental murine B16 melanoma metastases has been examined at different stages in the progressive growth of metastatic lesions. The recruitment of thioglycollate-elicited peritoneal exudate cells and peritoneal exudate cells activated in vitro with muramyl dipeptide was studied. Tumor-associated macrophages and labeled peritoneal exudate cells were identified in paraffin sections by specific histochemical staining and their density in individual metastases measured morphometrically. The density of tumor-associated macrophages and exogenously recruited peritoneal exudate cells was high in very small lesions but decreased rapidly as a function of enlargement of metastases, MD:An; where MD is macrophage density, A is the cross-sectional area of the lesion and n is a negative number. No significant difference was observed in the recruitment of activated and nonactivated peritoneal exudate cells. These results suggest that decreased recruitment of macrophages from the circulation may explain the decrease in the density of tumor-associated macrophages as metastases grow and indicate that macrophage activation is not accompanied by enhanced localization and/or uptake of macrophages into metastases.

Animals↗

PubMed1987

Drug delivery to macrophages for the therapy of cancer and infectious diseases.

The mechanisms by which mononuclear phagocytes discriminate between self and nonself, recognize foreign materials, senescent, damaged, old, or effete cells, and tumor cells are unknown. However, regardless of the mechanism(s) involved, once activated by the appropriate signal(s), macrophages are able to selectively recognize and destroy neoplastic cells in vitro and in vivo. Liposomes injected intravenously, in common with other particulate or polymeric matrices, localize preferentially in organs with high mononuclear phagocyte activity and in circulating blood monocytes. This behavior allows microparticulates to serve as a convenient system for the selective delivery of encapsulated drugs to cells of the mononuclear phagocyte series in vivo. Liposomes are a particularly attractive experimental system because of their capacity to incorporate a wide variety of water-soluble and lipid-soluble drugs. At this time, however, there is no reason to assume that a liposome-based drug delivery system will offer any significant therapeutic advantage compared to other microparticulate drug delivery systems. As in commercial development of any pharmaceutical preparation, considerations of cost-of-goods, shelf life, and acceptance of the formulation and dosing regimen by both physicians and patients will be of major importance in determining success and widespread clinical use. Liposomes containing macrophage-activating agents are highly effective at augmenting macrophage-mediated tumoricidal activity in vitro eradicating tumor metastasis in vivo, as well as protecting animals from a wide variety of microbial and viral infections. Although the demands of solving the scientific and technical problems associated with liposome development are substantial, the rapid rate of progress in biology and in pharmaceutical sciences enhances the prospect of success for at least several aspects of liposome-mediated drug delivery. The next few years will be crucial in determining whether the commercial development of liposomes is feasible or whether they will join the ranks of other drug carrier designs that have failed to fulfill their initial promise.

Animals↗

PubMed1985

Sequential histochemical staining for resident and recruited macrophages.

A new histochemical technique is described that permits differentiation of resident from recruited macrophages by staining of paraffin sections of tissues from rats and mice. Resident macrophages are identified by their ability to phagocytose and retain intravenously injected colloidal Prussian blue. New macrophages that emigrate into tissue are identified by phagocytosis of a second colloid, iron dextran. Paraffin sections of formalin-fixed tissues are sequentially stained for the presence of the two colloids with different chromogens, the endogenous pseudo-peroxidase activity of colloidal Prussian blue used to catalyze the polymerization of diaminobenzidine and after conversion of iron dextran to Prussian blue, the second colloid used to catalyze the polymerization of tetramethylbenzidine. The staining results in resident macrophages staining brown while newly recruited macrophages stain blue. The studies have shown that colloidal Prussian blue is stable in vivo and neither loses its catalytic activity nor undergoes extensive redistribution. They also show that the technique can be used to measure Kupffer cell recruitment stimulated by complete Freund's adjuvant in rats and tumor-associated macrophage recruitment in subcutaneous and spontaneous liver metastases in mice.

Animals↗

PubMed1985

Gold-induced immune thrombocytopenia in the dog.

In two seven-year studies with gold compounds in dogs of both sexes, thrombocytopenia was observed after 45 to 72 months of dosing in three of 14 and two of 14 dogs in high-dose groups that received 2.4 to 3.6 mg/kg of auranofin per day orally or 0.5 to 2.0 mg/kg of gold sodium thiomalate intramuscularly once every three days, respectively. An immune basis for the disorder was suggested by the apparent consumptive nature of the thrombocytopenia (increased bone marrow megakaryocytes and large peripheral blood platelets), the response to corticosteroid therapy and the demonstration of increased platelet-associated immunoglobulin. The latter was demonstrated with a solid phase radioimmunoassay and by electron microscopy using a staphylococcal protein A-colloidal gold conjugate. Platelet-associated immunoglobulin decreased as the platelet counts rose, and in one dog monitored over periods of steroid-induced remissions and subsequent relapses, the amount of platelet-associated immunoglobulin G correlated inversely with the platelet count (r = 0.82). These findings suggest that the long-term administration of gold compounds in dogs is associated with a dose-dependent incidence of thrombocytopenia, which is immune-mediated and similar to that associated with parenteral chrysotherapy in man. The application of tests for platelet-associated immunoglobulin to canine patients with immune thrombocytopenia should be useful in the diagnosis of the disorder in clinical practice.

Animals↗

PubMed1985

Changes in the macrophage content of lung metastases at different stages in tumor growth.

The macrophage content of experimental B16 melanoma metastases at different stages of their growth has been quantified with the use of morphometry in conjunction with a recently developed histochemical method for selectively staining intratumoral macrophages. Data are presented from analyses of 954 sections of 155 individual lung metastases, showing that the macrophage content of individual B16 melanoma lung metastases not only varies significantly but also falls dramatically once metastases contain more than 700 tumor cells. In addition to providing new information on host response reactions of micrometastases, these experiments also indicate that conclusions on intratumoral macrophages derived from studies of large primary tumors and metastases in advanced stages of growth may have little or no relevance to events in micrometastases.

Animals↗

PubMed1983

New histochemical method for measuring intratumoral macrophages and macrophage recruitment into experimental metastases.

A new double-label histochemical method is described which permits accurate quantitation of macrophage recruitment into neoplastic lesions in situ. Intratumoral macrophages are identified by their capacity to ingest colloidal iron particles from the interstitial fluid. Since colloidal iron is retained in a stable form within these cells for a considerable time, new macrophages that emigrate into the tissue after injection of the colloidal iron are identified by their ability to ingest a second colloid (lanthanum) which can be reliably distinguished from the initial iron label. Preexisting (colloidal iron label) and newly recruited macrophages (lanthanum label) are identified in serial sections by histochemical methods using hydrogen peroxide oxidation to detect iron (blue reaction product) and cleavage of phosphate esters to demonstrate lanthanum (magenta reaction product). The macrophage content and macrophage recruitment were found to vary substantially in individual metastases within the same host.

Animals↗

PubMed1981

Autoradiographic distribution of hematoporphyrin derivative in normal and tumor tissue of the mouse.

The distribution of isotopically labeled hematoporphyrin derivative (HPD) has been studied in mice bearing the spontaneous mammary tumor (fast growing). In stomach, liver, spleen, and pancreas, 3 hr after i.p. injection of [3H]HPD, grains were uniformly distributed over the tissue sections. After 24 hr, the grain density overlying parenchymous areas of these tissues was lower than that over the stromal or reticuloendothelial areas. In the spontaneous mammary tumor (fast growing), higher grain densities were seen over pseudocapsule, stromal septa, and necrotic areas at 3, 6, 12, 24, and 48 hr after injection. At 168 hr postinjection, only isolated stomal cells, presumably macrophages, showed high grain densities. From the temporal changes observed in the distributions of HPD in normal tissues and the relative stability of the distribution seen in the spontaneous mammary tumor (fast growing), we speculate that tissue factors such as vascular permeability, lack of an adequate lymphatic drainage, and nonspecific binding of serum proteins to stromal elements may be responsible for or contribute to the preferential uptake and/or retention of HPD observed in both human and animal tumors.

Animals↗

PubMedDate not supplied

Induction of suppressor cell activity in vivo and suppression of lymphoproliferative responses in vitro by SK&F 105.685 in the dog.

SK&F 105.685 (N,N-dimethyl-8,8-dipropyl-2-azaspiro[4.5]decane-2-propanamine+ ++ dihydrochloride) is a novel azaspirane with beneficial activity in rat models of adjuvant-induced arthritis and experimental autoimmune encephalomyelitis as well as in the murine lupus model. The mechanism of action in these models appears to be the induction of non-specific suppressor cell activity which is measured by the ability of cells from treated animals to partially inhibit the proliferative response of lymphocytes from control animals to concanavalin A (ConA) in a co-culture assay. In this study we have shown that oral administration of 0.1-3 mg/kg/day of SK&F 105.685 to purebred beagle dogs induced suppressor cell activity in the spleen and bone marrow but not in the peripheral blood. In vitro, SK&F 105.685 partially suppressed the proliferative response of dog splenocytes to the mitogens phytohemagglutinin (PHA), ConA and, to a lesser extent, pokeweed mitogen (PWM). Peripheral blood lymphocytes (PBLs) differed from spleen cells in their susceptibility to suppression by SK&F 105.685. While the PWM and ConA responses of PBLs and spleen cells showed similar levels of inhibition, the PHA response of PBLs, in marked contrast to spleen cells, was resistant to suppression by the compound. Our results show that the immunoregulatory effects of SK&F 105,685 are not limited to rodents and that suppressor cell activity in dogs is induced quickly and by relatively low doses of the compound.

Adjuvants, Immunologic↗

PubMedDate not supplied

Single-organism model of host defense against infection: a novel immunotoxicologic approach to evaluate immunomodulatory drugs.

The immunotoxicologic effects of drugs on host defense have been studied widely using various animal models of infection. Here we describe a new approach to testing host defense by using a single organism (Candida albicans) in CBA/J mice. The model is configured to test 3 effector systems via different routes of inoculation to stimulate different effector arms of the immune response. Nonspecific immunity was evaluated by C. albicans colony-forming unit (CFU) count from the spleen at 2 hr (uptake) and > or = 22 hr (clearance) following intravenous inoculation. Cell-mediated immunity was assessed by CFU count from an intramuscular injection site 6 days postinoculation. Humoral immunity was assessed by anti-Candida antibody titer, following multiple subcutaneous immunizations with C. albicans. Finally, overall immunity was evaluated following intravenous injection using survival as the endpoint. Histopathological, immunohistochemical, and electron microscopic evaluation of selected tissues revealed the involvement of the expected cell types in the different effector systems. Several immunomodulatory drugs--dexamethasone, cyclosporine, liposomal muramyltripeptide phosphatidylethanolamine, and SK&F 105685--were evaluated in the C. albicans model. Dexamethasone impaired host defense against C. albicans by suppressing all endpoints measured. Similarly, cyclosporine showed broad immunosuppressive activity, with the exception of yeast uptake from the spleen. In contrast, muramyl tripeptide-phosphatidylethanolamine enhanced all but cell-mediated immunity to C. albicans. SK&F 105685 displayed both stimulatory and inhibitory effects on immune responses to the infection. Our studies demonstrate that a single organism-based approach can be a useful method for evaluating the immunological hazards of drugs on host resistance to infection.

Adjuvants, Immunologic↗

PubMedDate not supplied

Practical aspects of including functional endpoints in developmental toxicity studies. Case study: immune function in HuCD4 transgenic mice exposed to anti-CD4 MAb in utero.

Keliximab is a human-cynomolgus monkey chimeric (Primatized) monoclonal antibody with specificity for human and chimpanzee CD4. As the preclinical safety assessment of biopharmaceuticals requires evaluation in pharmacologically responsive species, comprehensive toxicology studies, including reproductive toxicity, of this antibody were conducted in a human CD4 transgenic mouse model. The reproductive toxicology studies included a pre- and postnatal development study that incorporated immunotoxicological evaluation of offspring (F1) mice. The potential effects of exposure to treating maternal mice (F0) with keliximab during pregnancy and lactation on offspring viability, physical growth, neurobehavioral development, reproductive function, lymphoid tissue morphological structure, lymphocyte subsets and host resistance to Candida albicans infection were assessed. The results showed no impairment of these functions. The use of F1 transgenic mice in study with keliximab provides an example of a novel practical approach to assess developmental immunotoxicity within a study of pre- and postnatal development designed in accordance with ICH Guidelines.

Age Factors↗