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Biomedical subjects

G Strassmann

Publications and source records attributed to G Strassmann.

At least 37 records · Page 2Linked to original sources

[Radiotherapy of epicondylopathy of the humerus].

OBJECTIVE: To assess the efficacy of radiotherapy in alleviating pain at rest and on exercise in tennis elbow (humeral epicondylitis). PATIENTS AND METHODS: 45 elbow joints in 41 patients were radiated with a telecobalt unit in six sessions at a dose of 1.0 Gy each spread over 3 weeks. Indication for this treatment was pain in the elbow joint at rest, on pressure and on exercise. The patients were re-assessed after a mean follow-up period of 7.5 weeks. They were graded into one of five groups on the basis of their own assessment. Pain on exercise was determined by the Thompson hand-grip, chair test, forced extension and middle-finger stretch test. RESULTS: Satisfactory analgesia was achieved in 31 of 45 elbow joints (68.9%). About 50% of patients still had objectifiable pain on exercise. CONCLUSIONS: Radiotherapy is a highly efficacious means of pain alleviation in tennis elbow, but the results are better for pain at rest than on exercise. The Thompson hand-grip and chair test, positive in more than 90% of patients, proved to be reliable criteria to assess the indications for radiotherapy and its results.

Adult↗

Vesnarinone inhibits immune-mediated but not Fas (CD95) agonist-mediated hepatic injury.

Previous studies have shown that the administration of concanavalin A (ConA) into mice induces immune-mediated liver injury, which can be largely abrogated by neutralizing tumor necrosis factor(TNF)alpha. Vesnarinone is an experimental drug which is known to inhibit TNF alpha release. Here we demonstrate that vesnarinone inhibits ConA-induced hepatic injury. In a dose-dependent manner, vesnarinone inhibits in several mouse strains the increase of serum aminotransferase concentrations. additional experiments show that vesnarinone inhibits ConA-mediated accumulation of DNA fragmentation in the liver. Furthermore, the drug significantly reduces the levels of circulating TNF alpha and interleukin-6 (IL-6). Vesnarinone does not modulate TNF alpha and IL-6 action on hepatic cells, as shown by its failure to reduce the cytokine specific-stimulation of acute phase plasma proteins in the rat hepatoma H-35 cell line. Neither vesnarinone nor anti-TNF alpha protect against direct liver injury induced by a sublethal dose of agonist anti-Fas (CD95) antibody. Taken together, these results suggest that vesnarinone blocks hepatic injury, in part by inhibiting the release of TNF alpha in vivo.

Acute-Phase Reaction↗

Simultaneous paclitaxel and radiotherapy: initial clinical experience in lung cancer and other malignancies.

This report summarizes results from a series of pilot trials using combined-modality chemoradiotherapy with paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) as a radiosensitizing agent in patients with cancers of the lung, cervix, and bladder. In a phase I study of paclitaxel/radiotherapy in patients with locally advanced non-small cell lung cancer, five paclitaxel dose levels were evaluated in conjunction with simultaneous radiation (total dose, 59.4 Gy). A minimum of five patients were treated at each dose level; paclitaxel doses ranged from 45 mg/m2 over 3 weeks (level 1) to 65 mg/m2 for 7 weeks. Of 34 enrolled patients, 25 are evaluable for toxicity and response. Side effects were generally moderate for this combined-modality therapy, although two patients at level 5 developed dose-limiting toxicities (grade 4 esophagitis and grade 3 pneumonitis). Among 25 evaluable patients, complete and partial response rates were 4% (one patient) and 64% (16 patients), respectively; eight patients had a minor response. Median survival was 6 months (range, 1 to 20 months). Therapy was well tolerated, suggesting that the combined modalities offer a practical, effective therapy for patients with non-small cell disease. A paclitaxel dose of 55 mg/m2 is recommended for further study of combined-modality chemoradiotherapy in this clinical setting. In another trial, 33 women with inoperable, locally advanced cervical cancer received carboplatin 50 mg/m2 via intravenous infusion simultaneously with external-beam radiation therapy and vaginal brachytherapy, to define the regimen's toxicity and safety. Among the 33 women, 78% achieved a complete response to therapy. The investigators next conducted a trial of paclitaxel 50 mg/m2 given weekly over 3 hours with the previous carboplatin/radiotherapy regimen in four women and documented two partial responses, one near-complete response, and one minor response, with moderate, manageable toxicity. In a final case report on a patient with recurrent bladder cancer, simultaneous radiotherapy and weekly paclitaxel 50 mg/m2 intravenously over 3 hours yielded a partial remission, prompting the investigators to plan a phase I study to confirm the regimen's efficacy and safety. Additional planned studies include a phase I trial of simultaneous chemoradiotherapy in patients with cancer of the head and neck.

Adult↗

192IR endovascular brachytherapy for avoidance of intimal hyperplasia after percutaneous transluminal angioplasty and stent implantation in peripheral vessels: 6 years of experience.

PURPOSE: Percutaneous transluminal angioplasty (PTA) with or without stent implantation is the accepted standard in the therapy of occlusive arterial disease. Despite improvements in the technique and medical equipment, there is still a restenosis rate of up to 40%. A high-dose-rate afterloading technique to avoid vascular stenosis or occlusion after PTA and subsequent stent implantation caused by intimal hyperplasia is presented with long-term results. METHODS AND MATERIALS: Intravascular brachytherapy with a 10-Ci 192Ir source was performed in cases of recurrent vascular occlusion or stenosis which appeared within 6 months after a previous PTA. After recanalization by PTA and stent implantation, a 9-Fr ReKa catheter was positioned within the stent to center the applicator with its tip 2 cm below the stent. This catheter served as a guide for a 5-Fr flexible applicator. After this procedure the isodose was calculated and a 12-Gy to 3-mm source distance was applied. The procedure was followed by 72 h of heparinization. RESULTS: From May 1990 to June 1996, 28 patients (21 male and seven female) were treated with endovascular brachytherapy. All patients had a clinically relevant restenosis or reocclusion of the arteria femoralis. Follow-up time ranged from 1 to 71 months. Twenty-eight patients had a sufficient follow-up time; 25 of these patients were examined. Twenty-one patients had treated vessel segments; four patients had no flow in the treated area. Two patients moved away with unknown addresses, and one patient died without any follow-up examination. Radiation-associated side effects were not notable. CONCLUSION: Intraluminal brachytherapy with 192Ir is a safe and useful procedure to avoid endovascular hyperplasia after transluminal percutaneous angioplasty.

Aged↗

Predominance of TH1 response in tumor-bearing mice and cancer patients treated with AS101.

BACKGROUND: Several studies have recently suggested that the immune response to malignant growths is regulated by distinct patterns of type 2 cytokine production. These cytokines, regulating the cytotoxic T-lymphocyte response in patients with advanced cancers, may be associated with disease progression. Evidence suggests that the T Helper 1 (TH1) and T Helper 2 (TH2) types of reaction are reciprocally regulated in vivo. The immunomodulator AS101 (ammonium trichloro[dioxoethylene-O,O']tellurate) was found to stimulate mouse and human cells to proliferate and secrete a variety of cytokines. Clinical trials using AS101 on cancer patients are now in progress. PURPOSE: The aim of this study was to evaluate the ability of AS101 to modulate TH1 and TH2 responses in tumor-bearing mice and in patients with advanced cancer. In addition, we investigated the association between the predominance of each type of response with the antitumoral effects of AS101. METHODS: Mice into which Lewis lung carcinoma (3LL) had been transplanted (n = 221) and cancer patients (n = 13) were treated with AS101 on alternate days, at 10 micrograms/mouse intraperitoneally, or for the patients, at 3 mg/m2 intravenously. The types were sarcoma, melanoma, and colon, lung, ovarian, and renal cancers. Cytokine levels were determined by immunoassay kits and compared with the paired Student's t test: in mice, they were tested in spleen cell supernatants; in humans, in sera and mononuclear cell supernatants. The chi-squared test was used to compare tumor volumes. All P values represent two-sided tests of statistical significance. RESULTS: Our results show that treatment of mice and patients with AS101 results in a clear predominance in TH1 responses, with a concomitant decrease in the TH2-type response. This was reflected by a significant enhancement in interleukin 2 (IL-2) and interferon gamma (IFN gamma) levels (P < .01) paralleled by a substantial decrease in IL-4 and IL-10 (P < .01). Moreover, the concentration of IL-12 was significantly increased (P < .01) in AS101-treated patients who also showed enhanced levels of natural and lymphokine-activated killer cell-mediated cytotoxicity. The statistically significant increases in IL-2 and IFN gamma levels, paralleled by the pronounced decrease in IL-4 and IL-10 in the AS101-treated mice, were associated with its antitumoral effects. In addition, systemic cotreatment of 3LL-transplanted mice with AS101 and anti-IL-12 antibodies partly abrogated the antitumoral effect of AS101. CONCLUSIONS: Immunotherapy with AS101 enhances TH1 function while interfering with the TH2 response. This TH1 trend may be related to the antitumor effects of AS101. IMPLICATIONS: Isolation and characterization of a distinct cytokine pattern in patients with advanced cancer treated with AS101 may contribute to the development of intervention strategies using this compound.

Adjuvants, Immunologic↗

IL-4 and IL-13 modulate IL-10 release in endotoxin-stimulated murine peritoneal mononuclear phagocytes.

Several recent reports presented conflicting data on the action of IL-4 and IL-13 in regulating the release of proinflammatory cytokines by human monocytes. Here we show that the regulation of cytokine release by IL-4 and IL-13 could be either inhibitory or stimulatory in LPS-treated murine peritoneal macrophages. When macrophages were treated with IL-13 or IL-4, between 6 and 24 hr prior to endotoxin challenge, TNF alpha and IL-6 levels were significantly augmented. On the other hand, when the cells were cotreated with LPS plus IL-13 or IL-4, the release of TNF alpha and IL-6 was inhibited. These effects of IL-4 and IL-13 were associated with the modulation of IL-10; pretreatment resulted in a decrease, whereas cotreatment gave rise to a dramatic increase in IL-10 levels. The inhibitory effect of IL-4 and IL-13 on the release of TNF alpha was partially reversed by neutralizing anti-IL10 antibody, and the inhibition of IL-6 release was completely reversed by the antibody. These data suggest that the mechanism of action of IL-13 and IL-4 in modulating macrophage TNF alpha and IL-6 release partially involves IL-10.

Adjuvants, Immunologic↗

The lack of an effect by insulin or insulin-like growth factor-1 in attenuating colon-2-mediated cancer cachexia.

In several studies, the anabolic hormones insulin-like growth factor-1 (IGF-1) and insulin attenuated several metabolic changes associated with cancer cachexia. In the present study, we evaluated the effect of these hormones on the cachexia associated with colon-26 (C-26) tumor. Healthy age-matched and tumor-bearing mice were treated with two daily doses of IGF-1 (50 micrograms/kg in toto), or insulin (1 U in toto). Determinants of cachexia were body and tumor weight, epididymal fat pad and serum glucose concentrations. Neither IGF-1 nor insulin treatment had a significant effect on the cachectic parameters of C-26-bearing mice. These hormones were biologically active, being capable of inducing weight gain in hypophysectomized mice and hypoglycemia, respectively. Although IGF-1 and insulin have been used to treat cancer-related weight loss, the research presented here suggests that the beneficial effect of these hormones is not universal.

Analysis of Variance↗

Mutational analysis of TNF-alpha gene reveals a regulatory role for the 3'-untranslated region in the genetic predisposition to lupus-like autoimmune disease.

Lupus-prone mice show reduced production of TNF-alpha and, upon long-term treatment with recombinant TNF-alpha, significant protection from disease development. Mutational analysis of the 5'-untranslated region (UTR) and 3'-UTR of the mouse TNF-alpha gene reveals a marked degree of polymorphism. Transient expression experiments in the RAW 264.7 macrophage-like cell line using the luciferase reporter system suggest an important role for the mutations in the 3'-UTR in the biosynthesis of TNF-alpha, and provide a molecular explanation for the reduced TNF-alpha production in lupus-prone NZW mice.

Animals↗

Macrophage-derived tumor necrosis factor and tumor-derived of leukemia inhibitory factor and interleukin-6: possible cellular mechanisms of cancer cachexia.

BACKGROUND: The cellular basis for augmented cytokine production in the tumor-bearing host is not known. Recently leukemia inhibitory factor (LIF) and interleukin (IL)-6, produced by a variety of tumors, have been implicated as mediators of cachexia. METHODS: Five murine tumor cell lines were tested for the production of these cytokines. 4JK tumor was further tested to determine if IL-1, tumor necrosis factor (TNF), or cocultivation with RAW 264 cells augmented IL-6 or LIF production. RESULTS: 4JK from in vivo tumors produced significantly more IL-6 than did 4JK from culture, indicating that tumor production of IL-6 and LIF is potentially augmented by infiltrating macrophages. When 4JK was cocultured with RAW 264 cells, TNF, or IL-1 in vitro, a three- to 15-fold increase in tumor production of LIF and IL-6 was noted (p2 < or = 0.03). Conversely, in coculture experiments performed with a neutralizing TNF antibody, a 50% reduction in tumor production of LIF ad IL-6 was noted (p2 < 0.04). Resting RAW cells produced only minimal quantities of TNF; however, when RAW cells were exposed to tumor-conditioned supernatant from 4JK, their TNF production was markedly increased. CONCLUSIONS: In the tumor microenvironment, host macrophages may be activated and produce inflammatory cytokines such as TNF. Local TNF then appears to act on tumor cells to stimulate production of IL-6 and LIF. Enhanced tumor production of cytokine mediators may contribute to deleterious effects of neoplastic growth on the host.

Animals↗

[Postoperative radiotherapy in the prevention of heterotopic ossification after endoprosthetic hip joint replacement].

BACKGROUND: Following total hip arthroplasty high-grade heterotopic ossification occurs with a range of 0.5 to 27%. Local postoperative hip irradiation using different dosage and fractionation schedules reduces the incidence in high-risk cases on an average of 8%. The present retrospective study compares results after conventionally fractionated and high-dose radiotherapy. PATIENTS AND METHOD: A total of 50 hips (46 patients) from 2 different risk groups had complete follow-up. In group I (40 hips [80.0%]) radiotherapy was indicated after surgical excision of pre-existing high-grade heterotopic ossification, in group II (10 hips [20.0%]) for several risk factors (contralateral heterotopic ossification [n = 7], hypertrophic osteoarthritis [n = 2], spondylosis hyperostotica [n = 1]). In 28/50 cases (56.0%) conventionally fractionated irradiation with total doses ranging from 12.0 to 20.0 Gy was given, in 22/50 hips (44.0%) a high-dose irradiation consisting of 10.0 Gy given in 2 fractions on each of the first 2 postoperative days was applied. After a minimal observation period of 6 months (median: 22 months, range: 6 to 56 months) roentgenograms were analysed using a modified Brooker score. RESULTS: At follow-up, 2 hips in group I had recurrence of high-grade heterotopic ossification with the stages IIIA and IVB. In 1 case radiotherapy was interrupted after 3 x 2.0 Gy due to sepsis (IIIA), in the other case ectopic bone recurred from bony islands which layed outside the radiation portal (IVB). In group II, 9 patients had stage 0 and 1 patient stage IA. Statistical analysis using the Wilcoxon test showed a highly significant reduction of the amount of pre-existing heterotopic ossification (p < 0.0001) for both fractionation schedules. The comparison of both fractionation groups with the Whitney-Mann-U-test (p = 0.92) showed no statistical significant difference. CONCLUSIONS: The data about the high therapeutic efficacy of postoperative radiotherapy for prevention of heterotopic ossification were confirmed. Both fractionation schedules led to a sufficient reduction of high-grade heterotopic ossification in the 2 treated risk groups.

Adult↗

Cyclic nucleotide phosphodiesterase type IV participates in the regulation of IL-10 and in the subsequent inhibition of TNF-alpha and IL-6 release by endotoxin-stimulated macrophages.

We have recently shown that PGE2 inhibits the release of TNF-alpha from LPS-stimulated murine peritoneal macrophages via a feedback mechanism involving IL-10. Here we demonstrate that a rolipram-sensitive phosphodiesterase (PDE) type IV participates in the regulation of IL-10 synthesis. Selective PDE IV inhibitors (rolipram and RO-20-1724), but not selective inhibitors of other types of PDE, significantly augment marcrophage IL-10 production and contribute to the inhibition of TNF-alpha and IL-6 release. The addition of rolipram to LPS-stimulated macrophages results in the accumulation of cAMP and in the significant augmentation of IL-10 release. Competitive PCR analysis reveals that the drug dramatically increases IL-10 mRNA, but does not affect TNF-alpha mRNA. The inhibitory effect of rolipram on TNF-alpha can be significantly but incompletely reversed by anti-IL-10 Ab, whereas the effect of the drug on IL-6 can be completely reversed by anti-IL-10. In endotoxemic mice, the administration of rolipram increases serum IL-10 and reduces TNF-alpha and IL-6 levels. Northern blot analysis of spleens from these mice shows that rolipram increases IL-10 mRNA, whereas TNF-alpha mRNA remains largely unchanged. These results suggest that a rolipram-sensitive PDE type IV is involved in the production of IL-10 and in turn contributes to the inhibition of TNF-alpha and IL-6 release.

2',3'-Cyclic Nucleotide 3'-Phosphodiesterase↗

Endogenous D-factor activity partially mediates the toxic but not the therapeutic effects of tumor necrosis factor.

We have earlier shown that passive immunization against differentiation-inducing factor/leukemia-inhibitory factor (D factor) activity improves the survival of endotoxemic mice, suggesting that D factor may contribute to the systemic toxicity associated with tumor necrosis factor (TNF). In the current experiments, TNF induced D-factor gene expression in various tissues of non-tumor-bearing female C57BI/6 mice. Passive immunization against D-factor significantly improved survival after a lethal TNF challenge in both non-tumor-bearing (p2 < 0.02) and tumor-bearing mice (p2 < 0.01). In mice bearing 10-day s.c. MCA 105 sarcomas, D-factor antibody alone had no effect on tumor growth as compared with control IgG. Tumor regression and regrowth in mice treated i.v. with TNF was not affected by pre-treatment with D-factor antibody, as compared with pre-treatment with IgG. However, TNF-treatment-related mortality was abrogated by pre-treatment with D-factor antibody (0% vs. 36% for IgG-pre-treated controls). These results indicate that endogenous D-factor activity contributes to the toxicity but not to the anti-tumor effects of TNF therapy. With renewed interest in the use of TNF for the treatment of patients with cancer, improved understanding of the role of D factor in mediating the effects of TNF may have important clinical benefits.

Animals↗

Effect of liposome-mediated macrophage depletion on LPS-induced cytokine gene expression and radioprotection.

Tissue-specific cytokine mRNA expression was examined in mice that received LPS. In the liver, IL-6, IL-10, IL-12 (p40), and TNF-alpha were induced by 30 min after injection with LPS. In the spleen, IL-6 and TNF-alpha were induced by 30 min after LPS challenge, while increases in IL-10 and IL-12 (p40) were delayed in onset. GM-CSF, IFN-gamma, and IL-12 (p35) were not induced in the liver or spleen until 60 to 90 min after LPS injection. Mice were depleted of macrophages in their liver and spleen by i.v. injection of liposome-encapsulated dichloromethylene bisphosphonate (Cl2MBP). Induction of IL-1 beta, IL-6, IL-10, and IL-12 (p40) mRNA by LPS was reduced by > 95% in the liver of macrophage-depleted mice, implicating macrophages as the primary producers of these cytokines. Macrophage depletion resulted in a 50 to 75% reduction in TNF-alpha mRNA in the liver. The results from Cl2MBP-liposome-treated mice also suggested that splenic macrophages were the primary producers of LPS-induced IL-1 beta, IL-6, IL-12 (p40), and IL-1 receptor antagonist (IL-1ra) mRNA, but not IL-10 and TNF-alpha mRNA. Mice treated with Cl2MBP-liposomes were more susceptible to ionizing irradiation than control mice, whether or not they were administered a radioprotective dose of LPS. These findings suggest that depletion of liver and splenic macrophages results in a dysregulation of basal and LPS-induced cytokine responses that can be associated with an altered biologic response.

Animals↗

Potential involvement of IL-10 in suppressing tumor-associated macrophages. Colon-26-derived prostaglandin E2 inhibits TNF-alpha release via a mechanism involving IL-10.

The administration of murine TNF-alpha to colon (C)-26 bearing mice, significantly protects the host against the catabolic effects of the tumor. This effect of exogenous TNF-alpha can be primarily attributed to tumor lysis rather than to a direct anticachectic action. Murine peritoneal macrophages cultured with the C-26 line or with C-26 culture supernatant do not release TNF-alpha in response to LPS stimulation. The reduction in TNF-alpha levels is associated with a significant increase in IL-10 levels. Single cell suspension of freshly disaggregated C-26 tumor (which contains host macrophages), do not produce TNF-alpha but contain significant levels of PGE2 and IL-10. In contrast, PGE2 but not TNF-alpha or IL-10 can be detected in the C-26.IVX cell line that is used to generate tumors in vivo. Neutralizing anti IL-10 Ab but not isotype-matched Ab, significantly reverses the inhibitory effect of the tumor cells and their culture supernatant on macrophage TNF-alpha release. Additional evidence is presented to indicate that the C-26-derived inhibitory activity is related to PGE2. Taken together, these results support the hypothesis that tumor-derived PGE2 prevents tumor-infiltrating macrophages from producing TNF-alpha, in part by augmenting macrophage IL-10 synthesis.

Animals↗

Role of endogenous cytokines secretion in radioprotection conferred by the immunomodulator ammonium trichloro(dioxyethylene-0-0')tellurate.

The immunomodulator ammonium trichloro(dioxyethylene-0-0')tellurate (AS101) has previously been found by us to have radioprotective properties when injected into mice before sublethal and lethal doses of irradiation. AS101 also was found to protect mice from hematopoietic damage caused by various chemotherapeutic drugs. Based on these findings, phase II clinical trials with cancer patients treated with AS101, in combination with chemotherapy, are currently underway. In the present study, we wanted to assess the role of several cytokines in the radioprotection conferred by AS101. We show that the administration of neutralizing antibodies against interleukin-1 (IL-1) receptor, IL-6 receptor, IL-6, tumor necrosis factor (TNF), or stem cell factor (SCF) completely abrogates the ability of AS101 to increase the survival of lethally irradiated mice. Moreover, the injection of each of these antibodies reduces the ability of AS101 to increase the number of BM, spleen cells, and the number of circulating neutrophils, lymphocytes, and platelets in irradiated mice. In addition, these antibodies abrogate the enhancing effect of AS101 on the secretion of IL-3, IL-6, and granulocyte-macrophage colony-stimulating factor, all of which decrease significantly in sublethally irradiated mice. By contrast, the injection of anti-IL-2 receptor antibody or control Igs to AS101-treated mice does not interfere with the radioprotective effects of the compound. These results suggest a role for IL-1, IL-6, TNF alpha, and SCF in the radioprotective effect of AS101. Because cytokine toxicity remains a significant concern, the clinical application of AS101, which has no toxicity, is particularly valuable.

Adjuvants, Immunologic↗

Suramin treatment suppresses induction of experimental autoimmune uveoretinitis (EAU) in rodents.

The experimental drug suramin has been shown to possess several immunosuppressive properties. In this study we investigated the effect of suramin on the development of experimental autoimmune uveoretinitis (EAU) in mice and in rats. EAU was induced either by active immunization with a uveitogenic protein or peptide, or by the adoptive transfer of a uveitogenic T cell line. The development of EAU was assessed by clinical evaluation as well as by histopathology. Immunological responses were measured by delayed type hypersensitivity (DTH), lymphocyte proliferation, and serum antibody levels to the immunizing antigen. Suramin treatment was most effective in suppressing EAU when started concurrently with immunization (afferent). Treatment was less effective in suppressing disease when first administered 7 days after immunization or when given to animals that received an adoptive transfer of uveitogenic T cells (efferent). The effect of suramin on DTH and lymphocyte proliferation roughly paralleled its effect on EAU. Aferent treatment of mice with suramin completely suppressed anti-IRBP antibody titers. Interestingly, animals receiving efferent treatment had unreduced IgM levels but little or no IgG, suggesting prevention of the IgM-to-IgG switch. Depressed in vitro lymphocyte proliferative responses in animals treated with suramin during the afferent stage suggested that the suppressive effect on disease was due at least in part to an inhibition of antigen priming. Our results suggest that suramin merits further investigation as a potential treatment for some types of uveitis.

Animals↗

[Postoperative, conventional fractionated radiotherapy for prevention of heterotopic ossification after total endoprosthesis of the hip joint].

Radiotherapy is the only local means of treatment in the prevention of heterotopic bone formation. It is possible to reduce the incidence of HO following total hip arthroplasty from an average of 50% without further treatment to an average of 8% using different doses and fractionation schemes. In this retrospective clinical study 22 hips of 20 patients were treated with a conventional fractionated radiotherapy. Total doses of 12.0-20.0 Gy in daily fractionation of 200 cGy single doses were applied 18 hips were postoperatively irradiated as secondary prophylaxis against recurrence of HO. 4 hips were high-risk cases with contralateral HO after previous hip surgery. After 6-30 months observation periods the roentgenogramms were analyzed with a modified Brooker-Score. Patients with a score > II were classified as nonresponders. 95.5% of the treated hips showed satisfactory results, only one hip (4.5%) achieved a score IIIA. In this case radiotherapy was interrupted after 3 x 200 cGy. The high therapeutic efficiency of local irradiation in the prevention of heterotopic bone formation following total hip replacement could be proved. No considerable side effects were observed. Further prospective clinical investigations are necessary to optimize the doses and fractionation schemes.

Aged↗

Role of suramin as an IL-1 inhibitor in suppression of acute myelogenous leukemia progenitor proliferation.

Interleukin-1 (IL-1) modulates both autocrine and paracrine growth-stimulatory mechanisms of acute myelogenous leukemia (AML) cell proliferation. Recent studies show that blocking the interaction between IL-1 and its receptor may suppress this proliferation. Because suramin, a polysulfonated naphthylurea originally described as an antitrypanosomal agent, was found to inhibit the binding of several growth factors to their receptor, we tested its effect on AML progenitor proliferation. We first examined the effect of suramin on murine EL-4.6.1 cells that express type I IL-1 receptors and found that suramin inhibited the binding of IL-1 to its receptor. We then tested the effect of suramin on AML progenitors using bone marrow samples from 17 patients with AML. In all experiments, suramin inhibited AML blast proliferation in a dose-dependent fashion at concentrations ranging from 30 to 240 microM. IL-1 beta (100 U/mL) partially reversed this inhibitory effect. Suramin also inhibited normal early and mature hematopoietic progenitors, as assessed by both the delta assay and the mixed colony culture assay; however, at the same concentration, suramin suppressed the colony growth of colony-forming units granulocyte-macrophage (CFU-GM) by only 45% compared with an 89% suppression of AML progenitors. IL-1 beta did not negate this inhibitory effect, which suggests that another growth inhibitory mechanism might be operative. Our data suggest that suramin may inhibit AML progenitor proliferation by blocking the interaction of IL-1 and its receptor; therefore, further studies are warranted to evaluate suramin's therapeutic potential in patients with AML.

Adult↗