Influence of ceramide metabolism on P-glycoprotein function in immature acute myeloid leukemia KG1a cells

Previous studies have emphasized the role of glucosylceramide (Glu-Cer) synthase in multidrug resistance (MDR) regulation. However, the mechanism by which the inhibition of this enzyme results in increased drug retention and cytotoxicity remains unclear. In this study, we investigated the respective role of ceramide (Cer) accumulation and Glu-Cer derivatives depletion in MDR reversal effect of 1-phenyl-2-decanoylamino-3-morpholino-1-propanolol (PDMP), a Glu-Cer synthase inhibitor. We show here that treatment with PDMP resulted in increased rhodamine 123 (Rh123) retention and potent chemosensitization of P-glycoprotein (P-gp)-expressing cells, including KG1a cells, KG1a/200 cells, K562/138 cells, and K562/mdr-1 cells. Metabolic studies revealed that PDMP induced not only time-dependent Cer accumulation but also reduction of all glycosylated forms of Cer, including Glu-Cer, lactosylceramide (Lac-Cer), monosialo ganglioside (GM3) and disialo ganglioside (GD3). The influence of these metabolites on P-gp function was investigated by measuring Rh123 retention in PDMP-treated cells. P-gp function was found to be stimulated only by the addition of gangliosides in all resistant cell lines, whereas Glu-Cer, Lac-Cer, and Cer had no effect. Moreover, in KG1a/200 cells, GD3 and, to a lesser extent, GM3 were found to phosphorylate P-gp on serine residues. Altogether, these results suggest that, at least in leukemic cells, gangliosides depletion accounts for PDMP-mediated MDR reversal effect, and that gangliosides are important P-gp regulators perhaps through their capacity to modulate P-gp phosphorylation.

Differential expression of the efflux pumps P-glycoprotein and multidrug resistance-associated protein in human monocyte-derived dendritic cells

P-glycoprotein (P-gp), an ATP-binding cassette (ABC) drug efflux pump, has been recently shown to play an important role in the physiology of Langherans cells, a subtype of dendritic cells (DC) found in the skin. The present study was designed to investigate expression and activity of P-gp and of multidrug resistance-associated protein (MRP), another ABC efflux pump sharing numerous substrates with P-gp, in human monocyte-derived DC. Immunolabeling experiments and dye efflux assays indicated that such cells displayed elevated levels of MRP activity and expression when compared to those present in parental monocytes. Generation of DC from monocytes in the presence of the MRP inhibitor indomethacin did not, however, alter the capacity of DC to stimulate allogeneic T cells proliferation in mixed lymphocyte reaction. In addition, indomethacin did not inhibit the up-regulation of the CD1a, a marker occurring during the differentiation of monocytes into DC. In contrast to that of MRP, functional expression of P-gp was not detected in monocyte-derived DC. Such antigen presenting cells that constitute a promising tool for antitumor vaccinal therapy therefore display differential expression of the efflux pumps P-gp and MRP.

Phase I/II trial of the multidrug-resistance modulator valspodar combined with cisplatin and doxorubicin in refractory ovarian cancer

PURPOSE

To determine the maximum-tolerated dose (MTD) of doxorubicin when given in combination with cisplatin and the multidrug-resistance (MDR) modulator valspodar and the remission rate induced by this combination in patients with platinum- and anthracycline-resistant ovarian cancer.

PATIENTS AND METHODS

Fifty-nine patients who had failed prior platinum- and anthracycline-based chemotherapy were enrolled. During the dose-finding phase, patients received a loading dose of valspodar (1.5 or 2 mg/kg) via 2-hour intravenous (IV) infusion on day 1 and continuous IV infusion (CIVI) of valspodar (2, 4, or 10 mg/kg/d) over 3 days. Doxorubicin (starting from 20 up to 50 mg/m(2)) and cisplatin (50 mg/m(2)) were administered via 15- to 20-minute IV infusions on day 3. During the efficacy phase, patients received at least two treatment cycles unless toxicity was unacceptable, and responding patients and those with stable disease received four to six cycles.

RESULTS

All patients completed at least one cycle of combined treatment. The MTD of doxorubicin was determined to be 35 mg/m(2) when administered with valspodar at 2 mg/kg loading dose and 10 mg/kg/d CIVI plus 50 mg/m(2) cisplatin. At these doses, valspodar blood concentrations known to reverse MDR in vitro were reached in all patients. Valspodar was well tolerated at all dose levels. Dose-limiting toxicities of the combination were primarily hematologic and included febrile neutropenia and prolonged leucopenia. The addition of valspodar to the treatment did not worsen cisplatin-related toxicity. Among 33 patients treated at the MTD for doxorubicin, one (3%) had a complete response, and four (12%) had a partial response. An additional seven patients experienced a stabilization of their previously progressive disease. The survival rates at 6 and 12 months were 59% and 19%, respectively.

CONCLUSION

Valspodar can be safely coadministered with doxorubicin and cisplatin. Although the regimen used in this trial produced renewed responses in patients with heavily pretreated, refractory ovarian cancer, the value of valspodar in reversing resistance mediated by P-glycoprotein remains to be determined.

Multidrug resistance protein (MRP) activity in normal mature leukocytes and CD34-positive hematopoietic cells from peripheral blood

Multidrug resistance proteins (MRPs) such as MRP1, MRP2 and MRP3 are membrane efflux pumps involved in multidrug resistance and handling organic anions. In the present study, MRP activity was investigated in normal mature leucocytes and CD34-positive hematopoietic cells from peripheral blood using the flow cytometric carboxy-2',7'-dichlorofluorescein (CF) efflux assay. Basal and similar cellular exports of CF, an anionic fluorescent dye substrate for MRP1 and MRP2 transporters, were evidenced in lymphocytes whatever their subsets (CD3, CD4, CD8, CD20 and CD56 cells), in CD14 monocytes and in CD15 granulocytes whereas higher CF efflux was found in CD34 cells. Such outwardly-directed transports of CF were inhibited by known blockers of MRP function such as probenecid whereas the P-glycoprotein modulator verapamil did not alter the retention of the dye in the blood leukocytes. Peripheral mature blood leukocytes were moreover found to express MRP1 mRNAs and MRP1 protein as assessed by Northern-blot and Western-blot analyses, whereas MRP2 and MRP3 transcripts were not present or only at very low levels. Mature leukocytes therefore display basal constitutive MRP-related transport activity regardless of cell lineage and likely related to MRP1 expression whereas higher MRP-related efflux can be detected in peripheral CD34 hematopoietic cells.

Mechanical disintegration of sewage sludge

Mechanical disintegration can be used for an accelerated and improved anaerobic digestion of excess sludge. The hydrolysis is the limiting step of this process. Mechanical disintegration can be used to disrupt the cell walls and to cause the release of the organic material from the cells. Particle size analysis describes the size reduction but is not suitable for characterising the release of the organic material and the cell disruption. Two biochemical methods were developed for these phenomena. One of the parameters provides information about the disruption of micro-organisms, the other one gives information about the release of organic material. Different ultrasonic homogenizers, a high pressure homogenizer and stirred ball mills were used for disintegration experiments using various parameters. The influences of a mechanical disintegration on the particle size and of the energy intensity on the disintegration were investigated. Further investigations had to detect the influence of the solid content on the disintegration results. For sludge with a higher solid content better results in terms of energy consumption could be achieved. An optimum of the bead diameter and the stress intensity in stirred ball mills could be detected. A comparison of the results of different methods of sludge disintegration shows that the investigated ultrasonic homogenizers are inferior to a high pressure homogenizer and a stirred ball mill in terms of energy consumption.

P-glycoprotein as a drug target in the treatment of multidrug resistant cancer

Multidrug resistance (MDR) is a major obstacle to successful cancer chemotherapy. One important mechanism of MDR involves the multidrug transporter, P-glycoprotein (Pgp), which confers upon cancer cells the ability to resist lethal doses of certain cytotoxic drugs by pumping the drugs out of the cells and thus reducing their cytotoxicity. Pgp belongs to the ATP-binding cassette (ABC) family of transporter molecules which require hydrolysis of ATP to run the transport mechanism. The substrates of Pgp may be endogenous (steroid hormones, cytokines) or exogenous (cytostatic drugs). A number of studies have demonstrated a negative correlation between Pgp expression levels and chemosensitivity or survival in a range of human malignancies. In principle, Pgp mediated drug resistance can be circumvented by treatment regimens that either exclude Pgp substrate drugs or include Pgp inhibitory agents. Experimental studies have demonstrated that certain structural modifications of anthracyclines confer the ability to escape Pgp transport. The therapeutic benefit of Pgp inhibitors as chemosensitizers is currently being explored in phase III clinical trials, and the first promising results have already been reported. Another therapeutic option for Pgp inhibitors has recently evolved as several Pgp inhibitors, many of which are generally low-toxic substances, by themselves constrain proliferation and cause cell death by apoptosis in certain MDR cancer cell lines. The dual effect of Pgp inhibitors, targeting MDR cancer cells selectively, may translate into improved efficacy of cancer chemotherapy and perhaps new and less toxic drug treatment strategies in human MDR cancer.

Diverse effects of P-glycoprotein inhibitory agents on human leukemia cells expressing the multidrug resistance protein (MRP)

Multidrug resistance (MDR) to cancer chemotherapy is frequently associated with decreased drug accumulation in cancer cells due to drug expulsion by multidrug transporters such as P-glycoprotein (Pgp) and multidrug resistance protein (MRP). The novel resistance modifying agents PSC 833, 280-446, and LY 335979 are primarily targeted at inhibition of Pgp, and their MRP inhibitory potential is largely unknown.

OBJECTIVE

In the present study we addressed the effect of these agents on MRP-derived drug resistance.

MATERIALS

Drug-resistant human leukemia cells with Pgp+/MRP- (KG1a/200, K562/150) and Pgp-/MRP+ (HL60/130) phenotypes were maintained in suspension cultures for experimental studies of drug accumulation and drug sensitization by Pgp inhibitors.

METHODS

Intracellular accumulation of the fluorescent anthracycline daunorubicin was measured by flow cytometry and fluorescence detection. Daunorubicin dose-response curves were generated by non-linear regression of electronically measured cell counts of 72- - 96-h cultures. The half-maximal growth inhibitory dose (GI50) was used as measure of growth inhibition.

RESULTS

All MDR phenotypes studied exercised significant resistance to daunorubicin. PSC 833, 280-446 and LY335979 were equal in sensitizing Pgp+/MRP- cells to daunorubicin-induced growth inhibition (p < 0.0001). The Pgp-/MRP+ cells responded to PSC 833 and 280-446 by increased accumulation of daunorubicin (p = 0.0022 and p = 0.0005, respectively) and sensitization to the drug (p = 0.0009 and p = 0.0007, respectively). Conversely, LY335979 did not affect accumulation of daunorubicin in Pgp-/MRP+ cells nor sensitize these cells to daunorubicin.

CONCLUSION

Pgp inhibitory agents have differential effects on MRP-derived drug resistance which could be exploited in treatment of multidrug resistance in cancer patients.

Growth inhibition, cytokinesis failure and apoptosis of multidrug-resistant leukemia cells after treatment with P-glycoprotein inhibitory agents

The multidrug transporter P-glycoprotein (Pgp), which is frequently overexpressed in multidrug resistant leukemia, has many proposed physiological functions including involvement in transmembraneous transport of certain growth-regulating cytokines. Therefore, we studied cell growth of three pairs of drug resistant and sensitive leukemia cell lines (KG1a, K562 and HL60) exposed to three different inhibitors of Pgp. The resistant KG1a and K562 sublines, which expressed high levels of Pgp, responded to low doses of the cyclosporin SDZ PSC 833, the cyclopeptolide SDZ 280-446, and the cyclopropyldibenzosuberane LY335979 with a dose-dependent growth inhibition. In the resistant variants of KG1a and K562 cells the mean half-maximal growth inhibitory doses (GI50) of SDZ PSC 833 were 312 (SE 41) and 414 (SE 50) nM, those of SDZ 280-446 were 685 (SE 51) and 578 (SE 54) nM, and those of LY335979 were 66 (SE 1) and 48 (SE 8) nM, respectively. Exposure to 1 microM SDZ PSC 833 resulted in tetraploidization, cytokinesis failure and apoptosis of the KG1a and K562 MDR variants. Conversely, parental cells with no or low levels of Pgp and the non-Pgp resistant variant of HL60 cells were not receptive to these cytotoxic effects. We conclude that inhibition of Pgp may exercise selective cytotoxicity in Pgp-rich leukemia cells indicating a possible therapeutic target in multiresistant leukemia.

Human hepatoma cells rich in P-glycoprotein display enhanced in vitro invasive properties compared to P-glycoprotein-poor hepatoma cells

Whether the phenotypes of drug resistance and metastatic activity in cancer are dependent on each other or not is controversial. We compared in vitro invasive properties of human hepatoma cells resistant to epirubicin and rich in P-glycoprotein (Pgp) (HB8065/R) with the parental epirubicin-sensitive, Pgp-poor cells (HB8065/S). The HB8065/R cells displayed elevated capacity to migrate in a transwell chamber assay (three- to fourfold compared to the HB8065/S cells), both in the absence and presence of a reconstituted basement membrane extract (Matrigel). In the presence of the P-gp inhibitor PSC 833 (1.5 micrograms/ml) the capacity of the HB8065/R cells to cross Matrigel-coated filters was attenuated by approximately 25%. Compared to the HB8065/S cells, the resistant cell line expressed higher level of plasminogen activator inhibitor (PAI)-1 mRNA (approximately threefold), which was reflected by a approximately fivefold increase in secreted PAI-1 immunoactivity (approximately 50 ng/10(6) HB8065/R cells). Furthermore, treatment with PSC 833 was associated with upregulation of PAI-1 mRNA (approximately 3.5-fold) and immunoactivity (approximately twofold) in the HB8065/R cells. Level of tissue inhibitor of metalloproteinases (TIMP)-1 was also significantly increased in the HB8065/R cells compared to the HB8065/S cells, whereas both cell lines showed low constitutive expression of TIMP-2. Levels of TIMPs were not altered by PSC 833. These data suggest that overexpression of Pgp in these hepatoma cells may covariate with the phenotypes of both enhanced in vitro invasiveness and high PAI-1 expression, whether randomly acquired or not.

Cytotoxic effect of the cyclosporin PSC 833 in multidrug-resistant leukaemia cells with increased expression of P-glycoprotein

Multidrug resistance (MDR) to anti-cancer agents is frequently associated with overexpression of the drug efflux transporter P-glycoprotein (Pgp) in cancer cells, ensuing drug expulsion and maintenance of tolerable intracellular levels of certain cytotoxic drugs. Pgp may also be present in normal tissue, providing protection against toxic substances, but the physiological role of Pgp is not fully understood. Recently, it was shown that Pgp also takes part in the transport of certain growth-regulating cytokines (Drach et al, 1996; Raghu et al, 1996). Therefore, we studied the effect of the highly potent Pgp inhibitor PSC 833 on proliferation of three pairs of MDR and parental human cell lines (HB8065 hepatoma cells, KG1a and K562 leukaemia cells). The MDR phenotypes were characterized by Pgp overexpression, which was demonstrated by flow cytometry using the anti-Pgp antibody MRK16. Electronic cell counting of 72-96 h cultures revealed a dose-dependent antiproliferative effect of PSC 833 in the resistant KG1a/200 and K562/150 cells. The half-maximal growth inhibitory concentrations (GI50) were 0.2 microM and 0.7 microM respectively. Exposure to PSC 833 induced cell death by apoptosis in both cell types, as revealed by flow cytometry and detection of 3'-hydroxy ends of DNA (the result of DNA fragmentation associated with apoptosis), by terminal transferase-mediated dUTP-biotin nick end-labelling (TUNEL). Similar effects were not found in the hepatoma cell lines or the parental leukaemia lines. These results demonstrated a discriminating cytotoxicity of PSC 833 in two human leukaemia MDR variants, representing a possible therapeutic indication which warrants consideration during the ongoing clinical evaluation of this drug.

Increased potency and decreased elimination of lamifiban, a GPIIb-IIIa antagonist, in patients with severe renal dysfunction

Activation of the platelet membrane receptor glycoprotein (GP) IIb-IIIa is essential for thrombus formation. The novel nonpeptide GPIIb-IIIa antagonist, lamifiban, represents a promising approach for antiplatelet therapy in patients with cardiovascular disease. Since renal impairment frequently occurs in these patients, we designed a phase I study to assess the tolerability, pharmacodynamics and pharmacokinetics of lamifiban in patients with renal impairment. Four healthy volunteers (Group 1) with creatinine clearance (CLCR) >75 ml/min, eight patients (Group 2) with mild to moderately impaired renal function (CLCR 30-74 ml/min) and eight patients (Group 3) with severe renal impairment (CLCR 10-29 ml/min) were studied. They received stepwise increased doses of lamifiban intravenously (i.v.). There was a linear relationship between the systemic clearance of the drug and renal function (R2 = 0.86). The mean plasma concentration required for half-maximal inhibition of thrombin-receptor agonist peptide (TRAP) induced platelet aggregation (EC50) ex vivo was 21, 28 and 11 ng/ml in Groups 1, 2 and 3. The patients in Group 3 were sensitized to the antiplatelet effect allowing an 18-fold dosage reduction without compromising the pharmacodynamics. In conclusion, the decreased clearance of lamifiban may act in concert with increased potency of the drug in patients with severe renal impairment, and the drug dosage should be reduced accordingly.

Challenging drug resistance in cancer therapy--review of the First Nordic Conference on Chemoresistance in Cancer Treatment, October 9th and 10th, 1997

The First Nordic Conference on Chemoresistance in Cancer Treatment was held in the Danish town of Helsingør on October 9th and 10th, 1997, under the auspices of the Nordic Cancer Chemoresistance Group (NCCG). The meeting focused on biochemical chemoresistance in a multidisciplinary approach. There were 19 oral and 15 poster presentations documenting recent advances in experimental and clinical research of drug transport mechanisms, DNA repair systems, detoxifying enzymes, drug target regulation, in vitro sensitivity tests, apoptosis inhibition, and strategies to circumvent chemoresistance. In the present paper we review the main issues that were addressed and discuss the findings with reference to the current literature in the field. The meeting demonstrated the plurality and the complexity of chemoresistance, which is a major obstacle to successful chemotherapy in cancer patients. The new insights to mechanisms of drug resistance and sensitization represent a useful basis for further development of strategies to circumvent chemoresistance in clinical practice.

Human hepatoma cells rich in P-glycoprotein are sensitive to aclarubicin and resistant to three other anthracyclines

Drug resistance is a major obstacle to successful chemotherapy of primary liver cancer, which is associated with high expression of the multidrug resistance (MDR) gene product P-glycoprotein (Pgp), a multidrug efflux transporter. The most effective single agents in treatment of primary liver carcinoma belong to the anthracycline family, yet several anthracyclines are known to be substrates for Pgp. In the present study, we compared four anthracyclines with respect to cell growth inhibition, intracellular accumulation and cellular efflux using the HB8065/R human hepatoma cell line which is rich in Pgp, and the Pgp-poor parental line HB8065/S. The anthracyclines were also administered in conjunction with the Pgp-modifying agents verapamil and SDZ PSC 833 to assess modulation of resistance. The HB8065/R cells were sensitive to aclarubicin (ACL) and highly resistant to epirubicin (EPI), doxorubicin (DOX) and daunorubicin (DNR). SDZ PSC 833 enhanced accumulation, decreased efflux and increased cytotoxicity of EPI, DOX and DNR in the HB8065/R cells, but none of these effects was seen with ACL. In conclusion, ACL is apparently not transported by Pgp and retains its activity in a multidrug-resistant human hepatoma cell line; such properties can be exploited for clinical purposes.

Effect of oral terbinafine treatment on cyclosporin pharmacokinetics in organ transplant recipients with dermatophyte nail infection

Eleven patients with either kidney, heart or lung transplants, immunosuppressed with cyclosporin A, and with culture-proven dermatophyte toe nail infection, were given 250 mg terbinafine orally daily for 12 weeks. No changes in cyclosporin A dosage were made. A statistically significant decrease in mean specific cyclosporin A blood trough levels was found at 4, 8 and 12 weeks. No other statistically significant changes in the pharmacokinetic profile of cyclosporin A were seen. Terbinafine possibly induces a cyclosporin A metabolic degradation, which, however, is of little clinical significance. Terbinafine treatment is a safe therapeutical option in cyclosporin A-treated patients with dermatophyte nail infection. Cyclosporin A levels should be controlled during treatment.

P-glycoprotein is not expressed in a majority of colorectal carcinomas and is not regulated by mutant p53 in vivo

Overexpression of the MDR1 product, P-glycoprotein (Pgp), has been shown to be one of the mechanisms underlying the development of multidrug resistance (MDR). Recently, one mutant p53 has been shown to stimulate the MDR1 gene promoter in vitro, whereas wild-type p53 repressed this activity. We measured Pgp and p53 expression by immunoblotting in 34 colorectal tumours, and performed mutation analyses on the p53-positive tumours to confirm the presence of mutant p53 protein. Tumour DNA indices (DIs) were also measured using flow cytometry. Pgp was detected in 44% (15/34) of the tumours and in 100% (13/13) of the normal mucosas (P = 0.0005), with highest levels of expression seen in normal mucosa, suggesting that initial drug resistance in colorectal tumours is not caused by Pgp. Highly DNA aneuploid tumours demonstrated the lowest levels of Pgp expression relative to moderately aneuploid and diploid colorectal tumours. p53 protein was detected in 53% (18/34) of the tumours, and 12 of 14 p53-positive tumours had p53 gene mutations, p53-negative tumours had approximately twice the level of Pgp expression of p53-positive tumours. Pgp expression was not associated with either p53 expression (P = 0.73) or incidence of p53 gene mutation (P = 0.70), suggesting that mutant p53 does not induce Pgp overexpression in colorectal carcinomas.

Automated analysis of free and total concentrations of three antiepileptic drugs in plasma with on-line dialysis and high-performance liquid chromatography

A fully automated method for determination of the free and total concentration of drugs with a varying degree of protein binding is described. The antiepileptic drugs phenytoin, carbamazepine and phenobarbitone were chosen to demonstrate the utility of this technique. The method was based on the ASTED system and combined on-line equilibrium dialysis at 37 degrees C with concentration of the dialysate on a trace enrichment column and HPLC determination with UV detection. The dialysis cell was a modification of the ASTED dialysis cell and 22% of the free concentration of the drugs were recovered in the recipient channel of the dialyser after 10 min of dialysis at 37 degrees C. The free concentration, the total concentration as well as the drugs protein binding could be determined. The method was shown to be well suited for routine monitoring of the free and the total concentrations of the drugs in plasma from epileptic patients.

Binding diversity of antibodies against external and internal epitopes of the multidrug resistance gene product P-glycoprotein

P-glycoprotein (Pgp) is a trans-membraneous protein that is associated with multidrug resistance (MDR) in human cancer, including hepatocellular carcinomas and leukemias. There is no consensus regarding methods of choice for analysis of Pgp expression, and development of reliable analytical methods is now essential. We have studied the the Pgp expression in human hepatoma and leukemia cell lines using flow cytometry. The aim of the study was to compare binding properties of anti-Pgp antibodies reacting with surface (MRK16, UIC2) and cytoplasmic (C219, JSB-1) epitopes to assess which antibody performed best with respect to fluorescence discrimination. By histogram subtraction the fractions of resistant human hepatoma cells positive for Pgp were 99% (MRK16), 97% (UIC2), 77% (JSB-1), and 51% (C219), demonstrating variations in antibody reactivity. The resolution in detecting decreasing levels of Pgp in hepatoma cells was superior for the externally binding antibodies, showing that there is a correlation between antibody reactivity and fluorescence discrimination. Similar results were obtained for parental and resistant KG1a human leukemia cell lines. The Pgp epitopes remained reactive to the anti-Pgp MAbs after methanol fixation and cryopreservation. By dual parameter flow cytometry it was shown that Pgp expression in viable cells may be assessed together with uptake of epirubicin, which was low in cells expressing high levels of Pgp and vice versa. In conclusion, all tested antibodies proved useful for flow cytometric detection of high levels of Pgp, but the externally binding ones were superior in detection of low and variable levels of Pgp.

Clinical and biochemical long-term toxicity after postoperative cisplatin-based chemotherapy in patients with low-stage testicular cancer

In this case-control study the long-term chemotherapy-related morbidity was assessed in testicular cancer patients (> or = 5 years after treatment). The case group consisted of 47 patients with nonseminomatous testicular cancer who had undergone retroperitoneal surgery and 3-4 cycles of conventional-dose cisplatin-based chemotherapy (accumulated cisplatin dose: 300-400 mg/m2), also containing vinblastine and bleomycin. The results of the clinical and biochemical investigations and the patients' responses to a questionnaire were compared to similar observations from a control group comprising 47 patients treated with surgery only. In the case group the serum magnesium values and the levels of FVIIvWF were significantly lower (but within the normal range) than in the control group. Serum cholesterol values were distributed similarly in both groups. About 40% of the patients from the chemotherapy group still suffered from Raynaud-like phenomena and/or sensoric neurotoxicity as compared to 10% of the patients from the control group. Chemotherapy resulted in a significant elevation of serum LH within the normal range, probably associated with a slight subclinical Leydig cell dysfunction. Serum FSH levels were similar in the case and control groups, indicating an absence of long-term disturbance of spermatogenesis after chemotherapy. No increased cardiovascular morbidity was observed as a result of chemotherapy. Raynaud-like phenomena and sensoric neurotoxicity represent the principal clinical long-term side effects after 3-4 cycles of cisplatin-based chemotherapy containing vinblastine and bleomycin. Serum LH is slightly elevated after chemotherapy, whereas long-term spermatogenesis seems to be unaffected.

A 10-year experience with splenectomy in patients with malignant non-Hodgkin's lymphoma at the Norwegian Radium Hospital

BACKGROUND

Splenectomy is a major surgical intervention that has many implications for patients with malignant non-Hodgkin's lymphoma. As debated during the last few decades, the therapeutic benefit must outweigh the surgical risk and the loss of cellular immunity. A more liberal attitude toward splenectomy developed during the years 1980-1990 at the Norwegian Radium Hospital, as illustrated by the higher number of operations performed in the last 5 years (21 patients) compared to the first 5 years (14 patients).

METHODS

A 10-year retrospective review of the effects and side effects of splenectomy in 35 patients with malignant non-Hodgkin's lymphoma was performed, based on information obtained from the patient files at the authors' institution.

RESULTS

Clinical Stage IV disease was found in 29 patients (83%), and B symptoms in 15 patients (43%). At diagnosis, 26 patients (74%) had splenomegaly, and 8 patients (23%) had primary splenic lymphoma. The surgical mortality was 2.9%, and the morbidity was 37%. Infection was the most common complication, occurring in seven patients (20%). Pneumococcal vaccination had been performed in 13 patients, and the frequency of septicemia and pneumonia tended to be higher during follow-up in unvaccinated patients (not significant). Blood counts returned to normal during the first postoperative month in 18 of 25 patients (72%) who had cytopenia. After splenectomy, a durable remission was achieved in five patients (14%) who did not receive subsequent treatment.

CONCLUSIONS

Splenectomy has the potential to relieve local symptoms, correct cytopenias, and modify the disease course in patients with malignant non-Hodgkin's lymphomas, even in advanced stages, at the cost of an acceptable operative risk.

Long-term follow-up of pulmonary function in patients cured from testicular cancer with combination chemotherapy including bleomycin

A follow-up study of pulmonary function in two groups of patients with testicular cancer was performed 6-12 years after treatment. Both groups, 47 patients in each, had undergone retroperitoneal lymph node dissection (RPLND). Patients with pathological stage (ps) II had also received bleomycin (median 270 mg) and cisplatin (median 540 mg) in three or four courses which included vinblastine or etoposide. Patients in ps I and II were similar with respect to age, general health, observation period, inspired oxygen fraction (FiO2) and maximal arterial oxygen pressure (pO2) at RPLND, but four (8.2%) with psII disease developed densities on chest X-ray during chemotherapy. At the long-term follow-up the groups were similar with respect to physical exercise, smoking pattern, present drug treatment and history of cardiopulmonary disease. In both groups forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and single breath transfer factor for carbon monoxide (TLCO) were within normal limits, and no difference was found between the groups. The combined data for both groups showed that smoking was highly associated with impairment in TLCO (P = 0.005), and smoking frequency was negatively correlated to TLCO (P = 0.002). We conclude that 3-4 courses with bleomycin, cisplatin and etoposide/vinblastine in testicular cancer patients do not lead to long-term impairment of pulmonary function.

Chemical pleurodesis in malignant pleural effusions: a randomised prospective study of mepacrine versus bleomycin

BACKGROUND

The treatment of recurrent pleural effusion in advanced malignant disease should be efficient and with tolerable side effects. Since 1983 intrathoracic instillation of the anti-malaria drug mepacrine has been used to achieve pleurodesis. The cytotoxic drug bleomycin has been claimed to be equally effective and with fewer side effects. The present study was designed to compare these two agents.

METHODS

Forty patients with carcinoma and pleural effusions refractory to repeated pleural aspirations over the previous 12 weeks were randomised to receive treatment with intrathoracic instillation of mepacrine or bleomycin. Fluid volumes before and after pleurodesis, drainage time, and side effects were registered and analysed, and the response to treatment was evaluated by clinical examination and chest radiography.

RESULTS

The amount of fluid produced after treatment in the patients receiving mepacrine was lower than in those receiving bleomycin, and the duration of chest drainage was shorter. After 30 days 16 of 20 in the mepacrine group responded to treatment and 10 of 20 in the bleomycin group. Most patients died during the three months observation period. Moderate side effects occurred equally in both groups.

CONCLUSIONS

Chemical pleurodesis can reduce or stop pleural effusion in many patients, and in this study mepacrine appeared to be more efficient than bleomycin. A prospective study with a larger number of patients is now warranted.

Recombinant interferon α-2A combined with prednisone in metastatic renal-cell carcinoma: Treatment results, serum interferon levels and the development of antibodies

Five partial responses were seen in 23 patients with metastatic renal-cell carcinoma (MRCC) receiving interferon-alpha 2a (IFN)+prednisone (P). Four of 24 subsequent patients responded to IFN+P (combined response rate 19%). The median response duration was 8 months (3 to 30 months). The one-year survival for all eligible patients was 52%. Eight of 26 evaluable patients developed antibodies detected by an enzyme immunoassay. In 2 patients, high levels of neutralizing antibodies were also found, together with particularly low IFN levels. In one patient the development of neutralizing antibodies coincided with the loss of initial response. The treatment was well tolerated by most patients. Premature discontinuation of treatment was necessary in only 2 patients. In MRCC, combination treatment with IFN+P is as effective as IFN monotherapy (response rate 19%), with significantly reduced subjective toxicity. The clinical relevance of the development of antibodies against IFN requires further investigation.

Pulmonary toxicity of cytotoxic and immunosuppressive agents. A review

Cytotoxic agents may cause interstitial or eosinophilic pneumonitis, alveolar proteinosis, pulmonary venous occlusive disease, pulmonary fibrosis, pneumothorax, or pulmonary oedema. These agents may also potentiate lung injury caused by radiotherapy or high oxygen fractions in inspired air. Clinical and roentgenological features of lung damage induced by cytotoxic drugs are usually non-specific, and differential diagnoses include progression of the malignant disease and a plethora of opportunistic infections. Monitoring of blood gases and carbon monoxide transfer factor may facilitate early detection of drug induced lung injury. Fiberoptic bronchoscopy, bronchoalveolar lavage, transbronchial biopsy, or open lung biopsy may be necessary for reliable diagnosis. Early detection of lung damage and immediate withdrawal of the responsible agent(s) are essential. Steroids may be of therapeutic value in some patients.