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W Falk

Publications and source records attributed to W Falk.

At least 109 records · Page 6Linked to original sources
PubMed1985

[Radiation oncologic considerations on the treatment of cerebral metastases and personal experiences with 140 cases].

Cerebral metastases appear frequently and necessitate therapeutic measures. The authors report the incidence and particularities as well as the different modes of formation of metastases in the central nervous system. Surgical procedure should be carried out in case of favorable solitary metastases, young patients, and unknown primary tumors. Radiotherapy, which has proved for 30 years to be a valuable treatment method, has to be applied in a modified form in every case. Furthermore, the possibilities of chemotherapy should be studied and applied in a more intensive manner than hitherto. The chance of a one-year survival time is 22 to 44% for those patients presenting with an easily operable tumor. For the total group of radiotherapy patients suffering from various tumor types and generalized metastases, this rate is between 12% and 16%. Despite the short survival times, one should not forget that radiotherapy can produce many successful long-term results in case of cerebral metastases. Therapeutic nihilism is not the right attitude towards this problem.

Adult↗
PubMed1985

Induction of interleukin 2 responsiveness in thymocytes by synergistic action of interleukin 1 and interleukin 2.

Thymocyte cultures from C3H/HeJ mice were stimulated for proliferative responses with purified preparations of interleukin 1 (IL 1) and interleukin 2 (IL 2). Synergistic responses were obtained in the absence of mitogen. In the presence of excess IL 2, the thymocyte proliferation response was strictly dependent on the amount of IL 1 in the cultures. Antibodies to IL 1 inhibited the response in a dose-dependent manner. The combination of IL 1 plus IL 2 induced the appearance of IL 2 receptors on murine thymocytes as detected with a monoclonal antibody directed against the IL 2 receptor. Neither IL 1 nor IL 2 alone had this effect. The thymic subpopulation found to become IL 2 responsive upon IL 1 stimulus was the peanut agglutinin-negative (PNA-) medullary fraction.

Animals↗
PubMed1985

Suppression of cytotoxic T lymphocyte activation by L-ornithine.

The effect of L-ornithine on several types of immune reactions was analyzed. L-ornithine was found to suppress the activation of cytotoxic T lymphocytes (CTL) in vivo and in vitro. This suppressive effect was not observed with the structural analogues D-ornithine, L-lysine, or putrescine or with the amino acids L-histidine or L-alanine. The concentration of 9 X 10(-3) M L-ornithine was found to mediate a practically complete suppression of the cytotoxic response in vitro if applied on day 0 or day 1 of the culture, but a comparably weak suppression if applied on day 3. The same concentration of L-ornithine had no effect on the production of the lymphokines interleukin 2 (IL 2) and gamma-interferon (IFN-gamma). This concentration of ornithine had also no substantial effect on several types of proliferative responses, including the allogeneic mixed lymphocyte reaction, the concanavalin A-activated IL 2-dependent proliferation of thymocytes, and IL 2-dependent proliferation of the T cell clone W-2. These observations suggest that L-ornithine inhibits selectively the differentiation of CTL effector cells. By the criteria tested, the immunosuppressive effect of L-ornithine is more selective than that of cyclosporine A, which was previously found to suppress not only the activation of cytotoxic activity but also proliferative responses and the production of the lymphokines IL 2 and IFN-gamma.

Animals↗
PubMed1985

Induction of IL 2 receptor expression and cytotoxicity of thymocytes by stimulation with TCF1.

We investigated the role of T cell cytotoxicity inducing factor 1 (TCF1) in the induction of a cytotoxic T cell response. We found that help-deficient thymocyte cultures supplied with saturating amounts of purified IL 2 did not develop CTL in a 5-day culture. The expression of cytotoxicity was dependent on the addition of TCF1 derived from the T cell hybridoma K15. TCF1 also induced proliferation of thymocytes in the presence of IL 2. Only the PNA- thymocyte subpopulation responded to TCF1 with proliferation and cytotoxicity in the presence of IL 2. The monokine IL 1 also induced proliferation in this subpopulation but failed to induce cytotoxicity. IL 1 was further distinguished from TCF1 by inhibition of IL 1-induced but not TCF1-induced proliferation by anti-IL 1 antibodies. In addition, using anti-IL 2 receptor antibodies (AMT 13), we showed that TCF1 in the presence of IL 2 substantially increased IL 2 receptor expression in thymocytes. IL 1 had the same effect on induction of IL 2 receptor expression as TCF1. Because some effects of IL 1 and TCF1 are distinct and some overlap, we discuss whether IL 1 and TCF1 induce different subsets of PNA- thymocytes.

Animals↗
PubMed1985

Priming and triggering of tumoricidal and schistosomulicidal macrophages by two sequential lymphokine signals: interferon-gamma and macrophage cytotoxicity inducing factor 2.

We describe a new lymphokine activity, macrophage cytotoxicity inducing factor 2 (MCIF2), in the T cell mitogen-induced supernatant of a murine T cell clone in long-term culture. MCIF2 has the following properties: it elutes from a Sephadex G-100 column in three m.w. forms (10, 34, and 100 KD); it is acid labile (pH 2 to 4) and heat sensitive (80 min at 56 degrees C); it is not constitutively secreted, coexists in the same supernatant with immune interferon (IFN-gamma), and synergizes with IFN-gamma for induction of tumoricidal and schistosomulicidal resident peritoneal mouse macrophages. We uncoupled this synergy and show that IFN-gamma serves as the first ("priming") and MCIF2 as the second ("triggering") signal for macrophage activation. Application of the lymphokines in the reverse order was ineffective. These data demonstrate a two-step mechanism of macrophage activation.

Animals↗
PubMed1984

Capacity of different cell types to stimulate cytotoxic T lymphocyte precursor cells in the presence of interleukin 2.

Plastic-adherent cells enriched for dendritic cells (AC) were found to be among the most potent stimulator cells for the activation of cytotoxic T lymphocytes (CTL) in vitro in the presence of interleukin 2 (IL 2) and a constant second set of allogeneic stimulator cells. Concanavalin A-activated nylon wool-nonadherent spleen cells ( CNWT ), concanavalin A-activated unfractionated spleen cells ( Cspl ), and some variants of the ESb T lymphoma line were equally effective as stimulator cells, however, and provoked a substantial cytotoxic response at concentrations of 10(4) cells per culture or less. In contrast, nonactivated nylon wool-nonadherent spleen cells ( NWT ) or unfractionated spleen cells (Spl) and cells of the P815 mastocytoma, the Meth A fibrosarcoma, and the T cell lymphomas Ly 5178 Eb and ESb did not stimulate cytotoxic responses at these cell concentrations. The strong stimulatory potential of the Cspl preparation was reduced by treatment with anti-Thy-1 antibody plus complement, whereas the stimulatory activity of the AC preparation was resistant to this treatment. All cell types tested expressed class I major histocompatibility antigens. Nonactivated NWT cells, in contrast to the CNWT preparation, showed no detectable staining with anti-I-E or anti-I-A antibodies and also a slightly weaker staining with class I antisera. Experiments with the tumor cell lines revealed, however, that there was no strict correlation between stimulatory potential and density of class I alloantigens or the expression of I-E determinants. Experiments on primary cytotoxic responses in vivo gave similar results. Experiments in cultures with a single set of stimulator cells and I region-compatible responder cells indicated that AC and Cspl or CNWT also have a markedly stronger capacity than NWT to induce IL 2-dependent DNA synthesis.

Animals↗
PubMed1984

[Problems of cervical cancer and presentation of a new ring applicator for the afterloading technic with the selectron].

During our radiooncologic experience, we have learned the problems caused by insufficient information on the patient and his tumor. Histologic data, stage and a drawing of the extension of the tumor are generally submitted to the radiotherapist. This study is intended to remind that some other factors are important for the radiooncologic decision about local and temporal dose distribution, such as tumor size, endometrial extension to the fundus, frequency of metastases and recurrences, different histology/grading, and performed surgical technique/radicality. The vital importance of these factors is explained. A new circular applicator is presented for routine afterloading irradiation with the selectron. The applicator has proved to be useful in practice. The problems of the afterloading technique as against the radium technique are indicated, especially with regard to the dose rate in point A.

Adenocarcinoma↗
PubMed1983

Interferon-gamma is required in activation of macrophages for tumor cytotoxicity.

The participation of interferon-gamma in activation of murine macrophages for tumor cell lysis was investigated. Biochemically macrophage activation factor and interferon-gamma have not been separated. Antiviral titers correlated closely with macrophage activation in antigen- or mitogen-induced spleen cell supernatants. A monoclonal rat antibody that neutralized virus-induced interferon was also found to neutralize interferon-gamma in such supernatants. These monoclonal antibodies were coupled to CH-Sepharose 4B and used for absorption of antiviral activity from mitogen-induced spleen cell supernatants. Absorption of the interferon was paralleled by the reduction of the macrophage-activating capacity of the supernatants. Data from control absorptions supported the specificity of the absorption effect. These results indicate that interferon-gamma is required for activation of macrophages for tumor cell lysis. These results can be interpreted in two ways: (a) the monoclonal antibodies cross-react with interferon-gamma and with a mediator that is required for activation of macrophages for tumor cell lysis or (b) interferon-gamma itself is an essential cofactor for macrophage activation.

Animals↗
PubMed1983

The effect of liver cytosol on hepatic regeneration and tumor growth.

This report further evaluates the concept that the interaction of factors that originate within the liver can contribute, regulate or even initiate the actual development of hepatic regeneration after liver cell necrosis or partial hepatectomy. The effect of liver cytosol (100,000 g supernatant), both from intact adult rat liver (NLC) and from adult rat liver remnants that had been regenerating for 24 hours after 70% partial hepatectomy (PH) in posthepatectomy liver regeneration in the rat was studied. The specificity of the growth-controlling properties in liver cytosol was determined using tumor cells. The intraperitoneal administration of NLC after PH resulted in approximately 70-80% inhibition of the peak 3H-DNA specific activity seen in controls at 18 and 24 hours post-PH, with a significant increase in DNA synthesis at 31-40 hours post-PH. The intraperitoneal administration of RLC after PH, augmented the hepatic regenerative response normally produced. Autoradiographic determination of hepatic nuclear labeling confirmed the inhibitory and stimulatory properties of NLC and RLC respectively. Syngeneic NLC or RLC at six and 24 days after subcutaneous tumor inoculation resulted in significant inhibition of tumor growth for both a methylcholanthrene-induced bladder carcinoma (FBCa) and an HTC-hepatoma. The retardation of FBCa growth could be enhanced by administering NLC or RLC every three or seven days. Syngeneic and xenogeneic liver cytosol resulted in dose-dependent inhibition of P815 mastocytoma cell proliferation in vitro. It is apparent from these studies that both stimulatory and inhibitory factors can be extracted from liver tissue that not only influence liver cell regeneration, but also affect tumor growth. Further isolation and characterization of these factors may lead to an understanding of more fundamental problems such as the control of normal and malignant cell growth.

Animals↗
PubMed1983

Hyperthermochemotherapeutic in vivo isolated perfusion of the rat liver.

This report describes a system of in vivo isolated perfusion of the rat liver. The effects of perfusion with 5-fluorouracil (5-FU) (0.125-1.5 g/kg) on survival, liver function, and hepatic regeneration are studied. A dose of 0.125-0.25 g/kg of 5-FU produced acceptable toxicity with 0% and 25% mortality rate, but induced liver dysfunction indicated by abnormal biochemical values and severe inhibition of hepatic regeneration. Doses of 0.5 g/kg, 1.0 g/kg, and 1.5 g/kg produced a mortality of 60%, 100%, and 100%, respectively. Regional hyperthermia (37-43 degrees C) achieved by perfusion of the liver with heated saline produced an adverse effect on survival, liver function and hepatic regeneration, which are both temperature- and perfusion time-dependent. Hyperthermochemotherapy using in vivo isolated hepatic perfusion might be acceptable for the treatment of unresectable liver cancer, but should not be utilized as an adjuvant therapy prior to hepatic resection without the use of hepatic growth factors which could reverse the inhibitory effect of hepatic perfusion.

Alanine Transaminase↗
PubMed1983

Activation of cytotoxic T lymphocytes requires at least two spleen cell-derived helper factors besides interleukin 2.

The dependency of induction of T cell cytotoxicity on lymphokines was studied. 1 X 10(5) nylon wool-purified thymic lymphocytes or 10(4) spleen cells were cultured with TNP-haptenated syngeneic UV-irradiated spleen cells in the presence of a variety of lymphokine preparations. Concanavalin A-induced spleen cell supernatants mediated strong cytotoxic responses in this system. Three other preparations, namely, a partially purified IL 2 preparation from PMA-stimulated EL-4 thymoma cells, a Con A-induced spleen cell supernatant that was absorbed with an IL 2-dependent cell line, and a Con A-induced supernatant that was dialyzed at pH 2 were all ineffective in mediating a cytotoxic response. In reconstitution experiments, cytotoxic responses were only obtained when either the absorbed preparation or the pH 2-treated preparation was mixed with the IL 2 preparation from EL-4 cells. No reconstitution occurred after mixing of the absorbed with the pH 2-treated preparation. pH 2 treatment of the absorbed preparation did not abolish its synergistic effect when added to the IL 2 preparation from EL-4 cells. These results led to the conclusion that activation of cytotoxic lymphocyte precursors requires at least two other lymphokines in addition to IL 2. One T cell cytotoxicity-inducing factor (TCF1) remained in Con A-induced supernatants after absorption with IL 2 receptor-bearing T cell line cells. It was pH 2-resistant and was not found in EL-4 supernatants. A second T cell cytotoxicity-inducing factor (TCF2) was pH 2-sensitive and was found in Con A-induced spleen cell supernatants as well as in interferon-free supernatants of PMA-stimulated EL-4 cells. This activity co-purified with IL 2. It was absorbed by the IL 2-dependent T cell line together with IL 2. IL 2 differs from TCF2 since it is pH 2-resistant.

Absorption↗
PubMed1983

Reversal of lethal, chemotherapeutically induced acute hepatic necrosis in rats by regenerating liver cytosol.

In this report we further evaluate the role of regenerating liver cytosol (RLC) as a stimulator of hepatic regeneration by assessing its effect on survival, liver function, and hepatic regeneration in a model of in vivo isolated perfusion of the rat liver with high concentrations of cytotoxic drugs and regional hyperthermia. Isolated perfusion with 500 mg/kg of 5-fluorouracil (5-FU) and 2.5 mg/kg of mitomycin-C (Mit-C) resulted in 70% (n = 20) and 71% (n = 14) mortality, respectively, from 2 to 7 days after perfusion, with extensive, patchy necrosis and infarction seen on histologic examination and markedly elevated levels of serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) at 6 and 24 hours after perfusion. The intraperitoneal administration of RLC (80 mg total protein/rat) at the time of hepatic perfusion resulted in 70% (5-FU, n = 20, P less than 0.05) and 80% (Mit-C, n = 20, P less than 0.01) survival at 21 days post perfusion. RLC-treated rats demonstrated significantly lower SGOT and SGPT levels at 6 and 24 hours after perfusion and normal liver histologic appearance by 14 days after perfusion in surviving rats. Hepatic regenerative capacity following partial hepatectomy was severely inhibited (P less than 0.001) following isolated hepatic perfusion with sublethal doses of 5-FU (125 mg/kg, 250 mg/kg), Mit-C (1.5 mg/kg) and hyperthermia (41 degrees C and 43 degrees C X 5 minutes). The administration of RLC at the time of partial hepatectomy restored the DNA synthetic response in perfused rats to that seen in normal control rats after partial hepatectomy (P less than 0.05). These results demonstrate that the liver is the source of a factor (s) (RLC) that significantly improves survival after lethal chemotherapeutic injury to the liver by stimulating endogenous hepatic regeneration. A potential clinical application for a stimulator of hepatic regeneration in situations of deliberate, therapeutic insult to the liver is suggested.

Acute Disease↗
PubMed1982

Inhibition of chemotaxis by S-3-deazaadenosylhomocysteine in a mouse macrophage cell line.

Chemotaxis by a macrophage cell line, RAW264, is specifically inhibited by the intracellular accumulation of 3-deazaadenosylhomocysteine (3-deaza-AdoHcy). Intracellular accumulation of 3-deaza-AdoHcy is the result of incubation of the cells with 3-deazaadenosine, a compound that can function both as a substrate and as an inhibitor of adenosylhomocysteine (AdoHcy) hydrolase. Accumulation of AdoHcy per se, brought about in chemotactic cell lines by incubation with either 3-deazaadenosine or with 3-deazaaristeromycin, does not affect chemotaxis. The specific role of 3-deazaadenosine as an inhibitor of macrophage cell line chemotaxis is supported by the following findings. Another macrophage cell line, RAW309CR, is resistant to the inhibition of chemotaxis by 3-deazaadenosine, and the resistance can be ascribed to the failure to accumulate 3-deaza-AdoHcy in this cell line. It is noteworthy that both RAW264 and RAW309CR accumulate similar amounts of AdoHcy after incubation with 3-deazaadenosine. The difference in the accumulation of 3-deaza-AdoHcy in RAW264 and RAW309CR is explained by the finding that sonicates of RAW264 rapidly form 3-deaza-AdoHcy but sonicates of RAW309CR do not. Both hydrolysis of AdoHcy and the inhibition of the hydrolysis of AdoHcy by 3-deazaadenosine are the same in sonicates of the two macrophage cell lines.

Animals↗