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Biomedical subjects

P Groscurth

Publications and source records attributed to P Groscurth.

At least 109 records · Page 6Linked to original sources
PubMed1986

Distribution of polyhexyl cyanoacrylate nanoparticles in nude mice bearing human osteosarcoma.

[14C]Polyhexyl cyanoacrylate nanoparticles (PHCA), with diameters between 200 and 300 nm, were injected intravenously into nude mice bearing a human osteosarcoma. The distribution in liver, spleen, lung, heart, kidney, GI tract, gonads, brain, muscle, as well as in serum and transplanted tumor fragments was investigated by liquid scintillation counting. The peak levels in all organs with the exception of tumor and spleen were reached within 24 h. The highest levels were found in the organs of the reticuloendothelial system, liver, spleen, and lungs. The radioactivity in the other organs was found to be low, approximately 2%. In the tumor and the spleen the highest levels of radioactivity were found at approximately 7 d. At this stage the level of radioactivity in the tumor was 40 times higher than that in muscle. However, the amount of isotope detected in the tumor was still generally less than 1% of the injected dose. The concentration of radioactivity in the tumor was found to be quite variable. Higher levels of radioactivity were correlated with a low amount of tumor necrosis indicating the importance of viable tumor tissue for the accumulation of the radiolabel in this particular animal model.

Adult↗
PubMed1986

Cryopreservation of human fetal organs.

The effects of low temperature preservation on morphology, viability and differentiation capacity of different human fetal organs were studied using transmission (TEM) and scanning (SEM) electron microscopy, in vitro cultivation as well as xenogeneic transplantation. For this purpose fragments of lung, kidney, small intestine, thyroid, brain, liver and spleen from 10 human fetuses (aged 9 to 14 weeks of gestation) were frozen by a three step cooling procedure. After 3 to 12 months the specimens were thawed rapidly and processed for TEM and/or in vitro cultivation and/or transplantation into nude mice. TEM studies on frozen lung, kidney and intestine revealed generally a well preserved ultrastructure whereas liver and spleen fragments appeared highly necrotic. From three fetuses, frozen intestine and lung specimens were used for the establishment of monolayer cultures. Following trypsinization, both epithelial and mesenchymal cells formed a continuous layer on the bottom of plastic bottles. During further subpassages the number of epithelial cells decreased resulting in the formation of pure fibroblast cultures. Frozen brain tissue from one fetus was also successfully cultivated forming cell clusters and fiber bundles of variable size at the surface of glass cover slips. Following subcutaneous implantation into nude mice, the vast majority of fragments from lung, kidney, intestine and thyroid was found to grow in the recipients. The growth of xenografts was accompanied by persistence (kidney, intestine) or even increase (lung, thyroid) in cellular differentiation studied by TEM or autoradiography. Transplanted liver and spleen fragments, however, regularly regressed forming solid scars in the subcutaneous tissue of nude mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Persistence of vesicular stomatitis virus in cloned interleukin-2-dependent natural killer cell lines.

We have investigated virus-lymphocyte interactions by using cloned subpopulations of interleukin-2-dependent effector lymphocytes maintained in vitro. Cloned lines of H-2-restricted hapten- or virus-specific cytotoxic T lymphocytes (CTL) and alloantigen-specific CTL were resistant to productive infection by vesicular stomatitis virus (VSV). In contrast, cloned lines of natural killer (NK) cells were readily and persistently infected by VSV, a virus which is normally highly cytolytic. VSV-infected NK cells continued to proliferate, express viral surface antigen, and produce infectious virus. Furthermore, persistently infected NK cells showed no marked alteration of normal cellular morphology and continued to lyse NK-sensitive target cells albeit at a slightly but significantly reduced level. The persistence of VSV in NK cells did not appear to be caused by the generation of temperature-sensitive viral mutants, defective interfering particles, or interferon. Consequently, studies comparing the intracellular synthesis and maturation of VSV proteins in infected NK and mouse L cells were conducted. In contrast to L cells, in which host cell protein synthesis was essentially totally inhibited by infection, the infection of NK cells caused no marked diminution in the synthesis of host cell proteins. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of immunoprecipitates of viral proteins from infected cells showed that the maturation rate and size of VSV surface G glycoprotein were comparable in L cells and NK cells. Nucleocapsid (N) protein synthesis also appeared to be unaffected in NK cells. In contrast, the viral proteins NS and M appeared to be selectively degraded in NK cell extracts. Mixing experiments suggested that a protease in NK cells was responsible for the selective breakdown of VSV NS protein. Finally, VSV-infected NK cells were resistant to lysis by virus-specific CTL, suggesting that persistently infected NK cells may harbor virus and avoid cell-mediated immune destruction in an immunocompetent host.

Animals↗
PubMed1985

Central nervous system involvement in hairy cell leukemia.

A patient with central nervous system involvement by hairy cell leukemia is reported. Hairy cells were identified in the cerebrospinal fluid by electron microscopy and by tartrate-resistant acid phosphatase positive staining. Intrathecal treatment with methotrexate resulted in neurologic improvement, but was complicated by Cryptococcus neoformans meningitis. The leukemic phase of the disease was later successfully controlled by treatment with alpha interferon. Surface marker studies indicated a B- and T-cell phenotype of the hairy cells.

Brain Neoplasms↗
PubMed1985

A chemiluminescent assay for mycoplasmas in cell cultures.

A chemiluminescent assay for the detection of mycoplasma contamination of cell cultures is described. Cells (and supernatant) derived from mycoplasma-contaminated cultures stimulate a burst of luminol-dependent chemiluminescence in cell suspensions containing phagocytic effector cell types. The assay conditions for spleen cells, human and bovine polymorphonuclear leucocytes as the responder or indicator cells have been optimized. The chemiluminescent assay can be utilized for both monolayer and suspension cell cultures and is more sensitive than colony formation on agar plates and electron microscopy. Results are obtained within 3-5 h including the time required for the preparation of the indicator cells. CL can be measured in the tritium window of standard liquid scintillation spectrometers after switching off the coincidence circuit.

Cells, Cultured↗
PubMed1985

Clinical experience with preoperative chemotherapy for osteosarcoma.

Since 1978 preoperative chemotherapy has been administered to 15 consecutive patients with osteosarcomas in Zurich. Preoperative chemotherapy was acceptably well tolerated and did not impair surgical procedures. Our retrospective analysis confirmed that the extent of necrosis after preoperative chemotherapy is of biological importance for the further course of the disease. Patients with extensive necrosis had better relapse-free survival and longer overall survival than those with little necrosis.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1985

Ontogeny of renin immunoreactive cells in the human kidney.

We studied the time of appearance of renin-immunoreactive cells in prenatal human kidneys by immunohistochemistry and transmission electron microscopy (TEM). Renin immunoreactivity was detectable as early as the 5th or 6th gestational week in the mesonephros and appeared at 8 weeks of gestation in the metanephros. In a 8 week old embryo "renin granules" were seen by TEM in the juxtaglomerular epithelioid granular cells of metanephric tissue. In the embryos delivered by prostaglandin-induced abortion, granular renin immunoreactivity was also present in the cells of the proximal convoluted tubule. Our results support the contention that the renin-angio-tension system is active during fetal life and indicates a role for renin even during the embryonic period. In addition, they document a morphologically detectable effect of prostaglandins on the distribution of renin in the kidney.

Abortion, Induced↗
PubMed1985

Effects of leukocyte interferon (E. coli) on human bone sarcoma growth in vitro and in the nude mouse.

Effects of highly purified human leukocyte interferon (rIFN-alpha 2) on colony formation, DNA synthesis and proliferation in nude mice of tumor cells from eight bone sarcomas have been studied. rIFN-alpha 2 produced a dose-dependent inhibition of [3H]thymidine incorporation by sarcoma cells. Even at high doses (10(4) U/ml), however, [3H]thymidine uptake could not be completely blocked by rIFN-alpha 2. In a cloning assay three established sarcoma cell lines and five other sarcoma samples obtained after short-term in vitro culture were found to be sensitive to various degrees to rIFN-alpha 2, complete inhibition being seen only at 10(4) U/ml. Three sarcomas were sensitive in the nude mouse model. Scheduling experiments revealed that rIFN-alpha 2 produces a delay in tumor growth only when administered either before or shortly after tumor implantation. Therefore rIFN-alpha 2 appears to be most active when tumor size is small and growth not exponential, indicating that rIFN-alpha 2 may play a role in an adjuvant setting. Growth sarcomas strongly suppressed by rIFN-alpha 2 in the cloning assay was markedly inhibited in the nude mouse. One sarcoma which was only moderately sensitive in the cloning assay was resistant in the animal experiment, confirming the predictive value of the clonogenic assay. Although the present findings demonstrate strong antitumor activity of rIFN-alpha 2 against human bone sarcoma cells they should be interpreted with caution mainly because the high rIFN-alpha 2 levels used in the experiments cannot be maintained in patients over a prolonged period.

Adolescent↗
PubMed1985

Antiadhesive properties of biological surfaces are protective against stimulated granulocytes.

Despite the fact that a series of endogenous and exogenous inflammatory mediators are potent activators of circulating granulocytes, damage of vascular endothelium, a primary target tissue, is a rather unusual event in systemic inflammatory states. Since mediator-induced neutrophil hyperadhesiveness on plastic tissue culture dishes is invariably accompanied by intense release of lysosomal granule constituents and respiratory burst activation, thus representing a powerful model to investigate neutrophil cytotoxic states, comparative studies with neutrophils suspended in autologous plasma in the presence or absence of N-formyl-Met-Leu-Phe (2.5 microM), the most potent adhesion inducer, were performed on different biologic surfaces. On optimally adherent closed monolayers of cultured endothelial cells or fibroblasts we observed poor stimulation of adhesion as well as minimal granule release and hexose monophosphate pathway activation. Functional behavior of neutrophils on single molecular components of basal laminas such as fibronectin and collagen (type IV) coats was intermediate, with positive adhesion promotion but markedly reduced metabolic activation. When tested on endothelial cell-derived extracellular matrices, neutrophils again showed functional nonresponsiveness to N-formyl-Met-Leu-Phe. Scanning electron microscopy revealed an impressive congruency between the degree of cellular spreading and metabolic activation in the presence of N-formyl-Met-Leu-Phe, with maximally flattened neutrophils on plastic vs. nonspread, polarized cells on monolayers. Identical results were obtained by using other adhesion inducers such as complement-activated plasma or endotoxin. Lack of cell injury by N-formyl-Met-Leu-Phe-exposed neutrophils was corroborated by the absence of tracer release from [111In]tropolonate-labeled endothelium. These results indicate that biologic surfaces possess antiadhesive properties that protect them from cytotoxic damage by stimulated angry phagocytes.

Cell Adhesion↗
PubMed1985

Morphologic alterations of blood cells in the impedance aggregometer.

The scanning (SEM) and transmission (TEM) electron microscopic appearance of blood cells was studied in correlation with the aggregometer tracing recorded after activation of whole blood samples by collagen or ADP. Early morphologic alterations of platelets characterized by the formation of marginal pseudopods and bulbous protrusions were not indicated by the aggregometer. The initial increase in impedance was caused by the attachment of platelets displaying typical shape change morphology at the surface of the electrode wires joint with collagenous fibrils in collagen activated specimens. During further increase in impedance, aggregates were detectable in the blood suspension and at the electrode, the number and size of which increased up to the maximal extension of the aggregometer tracing. Using low doses of ADP (2-3 microM), dissociation of aggregates in the blood suspension was detectable by SEM, which was not recorded by the aggregometer tracing indicating further limitation of the impedance aggregometer. In collagen activated samples, platelet aggregates were covered by PMN and monocytes that in TEM displayed distinct phagocytosis of platelet fragments and fibrin masses. In ADP specimens, activation of leukocytes was only rarely detectable. The detection of mixed aggregates may be important for further employment of the impedance aggregometer in the diagnosis of hematologic diseases.

Adenosine Diphosphate↗
PubMed1984

Surface morphology of human platelets during in vitro aggregation.

The alterations of surface morphology of human platelets during the course of the aggregometer tracing were studied by scanning electron microscopy (SEM). Prior to activation the platelet rich plasma was pre-incubated at 37 degrees C for at least 30 min in order to obtain a sufficient number of discoid platelets. Immediately following the addition of collagen or ADP platelets showed slender pseudopods which thereafter were replaced by bulbous protrusions. The decrease in percent light transmission (%T) in the aggregometer tracing was characterized in SEM by a significant enlargement of bulbous protrusions and by the transformation of platelet shape from disc to sphere. During the increase in %T platelets forming primary aggregates displayed spiny pseudopods at their surface indicating that, during in vitro aggregation induced by collagen or ADP, two generations of pseudopods are formed. Using a low dose of ADP, the return of aggregometer tracing to the base line was regularly accompanied by dissociation of primary aggregates, but platelets remained spheroid and displayed pseudopods for a long time. Our study indicates that the course of aggregometer tracing is closely associated to the surface morphology of platelets. Single morphological changes, however, are not reflected by the aggregometer method.

Adenosine Diphosphate↗
PubMed1984

Induction of chemiluminescence during interaction of tumoricidal effector cell populations and tumor cells is dependent on the presence of mycoplasma.

A variety of host cells, such as activated macrophages, natural killer (NK) cells, and polymorphonuclear leukocytes (PMNL), are cytotoxic for an array of non-antibody-coated tumor cells. Because such effector cells appear to use oxygen-dependent mechanisms to effect tumor cell destruction in certain systems, the possibility of an involvement of toxic oxygen species has been considered. To investigate whether interaction of effector cells with neoplastic cells induces the generation of reactive oxygen species, resting and activated rat macrophages and rat spleen cells (as a source of NK activity) were exposed to viable tumor cells of varied origin, and chemiluminescence was monitored. This sensitive indicator of reactive oxygen generation was stimulated only when tumor cells or culture supernatants were contaminated with mycoplasma. Mycoplasma-free tumor cells and culture supernatants were in no case able to trigger chemiluminescence in any of these effector cell populations. On the other hand, tumor targets were equally susceptible to killing by effector cells irrespective of whether mycoplasma were present. The data suggest that generation of chemiluminescence during interaction of natural cytotoxic cells and neoplastic cells is an artifact and that reactive oxygen species do not function as an effector mechanism in antibody-independent natural killing effected by activated macrophages and NK cells.

Animals↗
PubMed1983

[The Zurich experience with preoperative high-dose methotrexate in osteosarcomas].

15 consecutive patients with osteosarcoma underwent preoperative chemotherapy with high dose methotrexate (HDMTX) containing regimens according to the T7 or T10 protocols of ROSEN, Preoperative chemotherapy was well tolerated and did not impair surgical procedures. 67% of the patients responded clinically with reduction of pain and tumor size. Histologic examination of the tumor after preoperative chemotherapy revealed extensive necrosis in 53% of patients. In a retrospective analysis, patients with extensive necrosis (group B) were compared with those with little or no necrosis (group A). Patients from group B had a longer relapse free and overall survival period than group A. In addition, patients of group A had significantly higher initial levels of alkaline phosphatase than group B. The incidence of a 2.5-fold increase of the transaminases 2-3 days after HDMTX was significantly greater in patients of group B compared to group A. In the absence of documented necrosis after chemotherapy according to the T7 or T10 protocols, further use of HDMTX is not indicated. New aspects on the treatment of osteosarcoma, derived from recent publications, are discussed.

Adolescent↗
PubMed1983

Characterization of cloned cytotoxic lymphocytes with NK-like activity.

Cloned H-2b-restricted male antigen-specific cytotoxic T cells were kept in culture in the presence of IL 2 for over 2 yr. During this time, they lost their antigenic specificity and now exhibit high NK-like activity. Three separate clones HY 1, HY 2, and HY 3 and their subclones, when tested on a panel of NK-sensitive and NK-insensitive target cells, showed typical lysis patterns of NK cells. Three cytotoxicity-loss mutants were obtained by subcloning. At least one of these cytotoxicity-loss mutants still exhibited binding to NK-sensitive target cells. The various HY clones were compared with cloned alloreactive cytotoxic T cells of B10 anti-B10.D2 specificity with respect to surface markers, target specificity, kinetics of lysis, morphology, and influence of monoclonal antibodies and chemicals on cytotoxicity. Only one major difference between cloned NK-like and alloreactive T cells was detected: monoclonal anti-Lyt-2 antibodies inhibited cytotoxic activity of alloreactive T cells but not of NK-like cells, although both expressed Lyt-2 on their surface. Morphologically, HY cells were characterized by numerous lysosomal granules in their cytoplasm. Clones with NK-like activity differed from cytotoxicity-loss mutants by both ultrastructural appearance and enzyme histochemistry of lysosomes. Interaction of NK-like cells with YAC-1 cells induced membrane lesions of variable size in target cells. Effects of chemicals influencing lysosomal pathways such as monensin, NH4Cl, and chloroquine on cytotoxicity were investigated. Monensin as well as NH4Cl inhibited cytotoxicity of NK as well as alloreactive clones, whereas chloroquine did not. Spleen cells from acutely virus-infected mice with high NK reactivity showed the same behavior except for chloroquine, which was slightly inhibitory. The addition of monensin to the cells resulted in morphologic changes in the lysosomal granules. These data strongly suggest that NK-like killing is triggered by unknown substance(s) released from lysosomes of effector cells. Cloning of antigen-specific cytotoxic T cells under conditions of limiting dilution and continuous growing in medium containing Con A supernatant but not the relevant antigen often leads to loss of specificity and appearance of NK-like activity. The results presented are representative of a great amount of work in this and probably many other laboratories attempting to clone cytotoxic effector T cells.

Animals↗
PubMed1982

Cytodifferentiation of human fetal lung tissue following transplantation into "nude" mice.

Lung fragments from 10 human fetuses aged 10 to 14 weeks of gestation were implanted into athymic "nude" mice. Cytodifferentiation of the transplants was studied by both scanning and transmission electron microscopy. Two weeks after implantation mitotic figures of epithelial and stroma cells were observed. In five week old transplants ciliated as well as endocrine cells were found dispersed among undifferentiated bronchial epithelium. During further experimental period epithelial differentiation in the transplants proceeded. Thus, eight week old implants assumed the morphologic appearance of fetal lungs in the canalicular stage displaying prospective type I and II pneumocytes. In addition stroma cells also differentiated forming mature fibroblasts and myofibroblasts. Our study indicates that human fetal lung tissue transplanted into "nude" mice not only grow but even differentiate. Xenogeneic transplantation of human fetal cells and tissues, therefore, offers additional opportunities to investigate the prenatal development of human tissues.

Animals↗