[Exercise testing in respiratory medicine]. / Belastungsuntersuchungen in der Pneumologie.

This document replaces the DGP recommendations published in 1998. Based on recent studies and a consensus conference, the indications, choice and performance of the adequate exercise testing method in its necessary technical and staffing setting are discussed. Detailed recommendations are provided: for arterial blood gas analysis and right heart catherterization during exercise, 6-minute walk test, spiroergometry, and stress echocardiography. The correct use of different exercise tests is discussed for specific situations in respiratory medicine: exercise induced asthma, monitoring of physical training or therapeutical interventions, preoperative risk stratification, and evaluation in occupational medicine.

[Off-label use: update and relevance for urology]. / Off-Label-Use: Update und Bezug zur Urologie.

The use of pharmaceuticals beyond the approved indication and conditions (off-label use) is of increasing public interest in times of necessary financial constraints in public health together with the high requirements for drug safety to protect the patient. Remarkably, more than half of the therapies in oncology are performed as off-label use. The discussion on off-label use is controversial and based on different points of interests. Evaluation of therapeutic agents by the pharmaceutical industry is predominantly driven by marketing and business requirements. As a consequence, treatment of rare diseases is often only possible by off-label use, creating more or less an off-label need. Reimbursement by health-care insurance is based on the approval of a pharmaceutical substance for a particular situation, because only the rigorous licensing process assures that the verified efficacy is higher than the, often severe, adverse side effects. It is a well known fact that the sometimes adverse events, which occur on administration of substances in an off-label fashion, are not included in the information on the regular use of a given drug. Finally, physicians request a controlled off-label use, which only allows experienced colleagues and (sub)-specialized oncologists to use pharmaceuticals in an off-label fashion. Up to date no legal documents exist that provide regulations for such an off-label usage.

[Does plasmatic dilution influence the validity of PSA-tests?]. / Beeinflusst das "Blutplasmavolumen" die Validität von PSA-Tests?

PURPOSE: The aim of this study is to improve the validity of PSA-based tests by considerations of the dilutions caused by the individual plasmatic blood volume (or other relevant body fluids). MATERIALS AND METHODS: Retrospective analyses of patients who underwent adenomectomy (n = 32) or radical prostatectomy (pT1 - 4 N0 M0; n = 60) were carried out. We calculated the PSA density (PSAD) and two new PSA-based parameters (mPSA (Vp), mPSAD (Vp)) that converted t-PSA concentration and PSAD with regard to individual Vp (according to Sprenger's modified Retzlaff formula). Comparative statistics of receiver operating characteristics (ROC-) curves, AUC, sensitivity, specificity, positive and negative predictive values for t-PSA, mPSA (Vp), PSAD and mPSAD (Vp) were performed. RESULTS: PSA was positively correlated with local tumour stage. With regard to the whole range of t-PSA (n = 92; 0.1 - 88.4 microg/L) the diagnostic selection between prostate carcinoma (CaP) and benign disease (BPH) was significantly improved by PSAD (AUC = 0.803) and mPSAD (Vp) (AUC = 0.806) (p < or = 0.003) compared to t-PSA und mPSA (Vp) (AUC = 0.531). Within the range of 4.0 - 10.0 microg/L PSA, the areas under the ROC curves were much better for t-PSA (AUC = 0.663), mPSA (Vp) (0.694) and PSAD (0.931) in gereral; mPSAD (Vp) provided the best AUC (0.947). However, although considering Vp does demonstrate better AUCs, this tendency does not reach the level of significance (yet). CONCLUSIONS: The most conclusive way to improve PSA test validity is to adjust PSA to different "volumes". Therefore, elaborated devices for a better preoperative investigation of the whole volume of the prostate gland and its distinct partial volumes (such as carcinoma or benign tissues), as well as applied knowledge on the distribution and kinetics of PSA in body fluids, might substantially help to optimise the detection of curable patients with unknown carcinoma of the prostate.

[Natural and artificial erections in spite of radical, non-nerve-sparing retropubic prostatectomy]. / Natürliche und artifizielle Erektionen trotz retropubischer, Nicht-Nerv(en)-Erhaltender Radikaler Prostatektomie (NNE-RP).

PURPOSE: The aim of this study was to evaluate sexual functions (SF) of patients after retropubic, non-nerve-sparing radical prostatectomy (NNS-RP). MATERIALS AND METHODS: A self-assessment survey on 213 selected patients (multiple choice questionnaire, 18 questions and 80 choices with regard to pre- and postoperative SF and course of tumor disease) was performed. The analysed parameters were demographics, sexual desire, capacities for erections and intercourses, orgasm, use of potency-supporting drugs and devices, attending physicians, life quality (LQ), and S100 immunohistochemical staining on neurovasculare bundles (NVB). RESULTS: The general response rate of the survey was 61.5 %. 123 data files were evaluable. 87 % of the patients reported on pre-operative erections (n = 107). Of these 12.1 % (n = 13) noticed residual nocturnal erections after NNS-RP. One patient had additional arbitrary full-erections that enabeled him to practice intercourse (< 50 % of attempts sufficient). Bilateral resections of NVB were confirmed on all histopathological specimens from erectile patients. Although 59.2 % of the patients reported on sexual desires (71/120) that persisted postoperatively, only 53.3 % (38/71) tested drugs or devices to induce or improve erections. 18 of these 38 patients (47.4 %) were finally capable of intercourses. 9 of 123 patients were sildenafil-responders, eight of them without any spontaneous erections. 23.8 % of the patients reported on a severe decrease in quality of life due to complete or partial loss of SF. However, only 62.6 % patients (77/123) asked for professional support regarding SF. For this purpose 88.3 % (68/77) consulted an urologist. CONCLUSIONS: The existence of residual spontaneous erectile activities and responses on sildenafil after NNS-RP indicate some kind of functional accessory routes for innervations besides the NVB (or submaximal resections). However, the prevalence and quality of the observed erections were clinically insignificant.

Port site recurrences after laparoscopic and thoracoscopic procedures in malignancy.

PURPOSE AND METHODS: A review of the literature was performed to determine the number of cases of port site recurrences (PSR) after laparoscopy or thoracoscopy. CANCERLINE and MEDLINE were searched, as were citings from retrieved and related papers. RESULTS: There have been 35 reported cases of PSR after laparoscopic colectomy for colorectal carcinoma, and 23 cases after thoracoscopic procedures for lung neoplasms. All of these have been reported since 1993. Since 1991, 12 cases have been described after laparoscopic cholecystectomy of unsuspected gallbladder carcinoma, and another case after biopsy of a known gallbladder carcinoma. Ten cases of PSR have been reported after laparoscopic procedures for ovarian lesions, often in the presence of peritoneal seeding at diagnosis. Other rare PSRs have been documented after several procedures in various malignancies. CONCLUSION: Enrollment of patients onto the ongoing intergroup study evaluating open versus laparoscopic resection of colon cancer should be encouraged. Until valid prospective data on PSR frequency are available, laparoscopic or thoracoscopic resection of malignancy off-protocol should be undertaken with circumspection.

[Urogenital cancer studies in view of new legislation]. / Uroonkologische Therapiestudien angesichts neuer Rechtssprechungen. Wege der AUO zur Entwicklung künftiger systemischer Nierentumortherapien in Deutschland.

Harmonization of European GCP-V-related decrees crushed German urogenital cancer study activities and has led to complete discontinuation of investigator-initiated studies since August 2004. For renal cell carcinoma, the two major branches of the German cancer society (Deutsche Krebsgesellschaft e.V.), the Association for Urogenital Oncology (AUO) and the Association for (Internal) Medical Oncology (AIO), founded a Renal Cancer Task Force Group composed of the active members of the former "Intergroup Competence Network Renal Carcinoma" (IKN-N) in the spring of 2004. The resulting intergroup consortium represents an overall community of more than 100 German clinical departments that are highly experienced in oncological studies and ready to go for future trials. The basic ideas of the concept were transparency, multilateral consultations within the Task Force, and early involvement of national and international representatives of pharmaceutical companies and medical care insurance providers in the process of future study developments. Therefore, two pharmaceutical hearings took place at the University of Frankfurt.

[Renal cancer study activities in Germany. Drug therapy]. / Studienlandschaft Nierenzellkarzinom. Medikamentöse Therapie.

Drug therapy of advanced renal cell carcinoma underwent rapid changes. Monotherapeutic, placebo-controlled protocols -- and more recently combinations of different targeted drugs -- dominated the global clinical studies in the past 2 years. The preliminary results are almost encouraging and international investigators, supported by the pharmaceutical industry, were most successful in enrolling patients quickly. The present article reviews the recent German drug study activities and indicates potential future projects.

[Recurrent disease in renal cell carcinoma. "Local recurrence" after kidney-sparing and radical resection]. / Rezidivtumor beim Nierenkarzinom. Das "Lokalrezidiv" nach nierenerhaltender oder radikaler Resektion.

Locally recurrent renal cell carcinoma (RCC) is 0-10% after nephron-sparing surgery, 2.5-4% after thermoablative interventions and 2-3% after (radical) nephrectomy. Risk-factors are: sporadic or hereditary origin, tumor size, multifocality, histologic phenotype and incomplete resection. To date, there are no significant differences in the incidence of locally recurrent tumors independently of whether open or laparoscopic techniques were preferred. Caution still has to be taken with the use of alternative tools for minimally invasive tumor ablation.Finally, no statistically proven standard therapy exists that would clearly provide a superior outcome for patients with an isolated local recurrence. However, meta-analyses strongly support the performance of a resection of the recurrence as the primary working principal.

[New targets and drugs for treatment of advanced renal cell carcinoma]. / Neue "Targets" und Substanzen zur medikamentösen Therapie des fortgeschrittenen Nierenzellkarzinoms.

Conventional immunotherapeutic approaches have failed to achieve fundamental benefits for clinical outcome of patients with advanced metastatic renal cell carcinoma (MRCC). New, encouraging substances have gained broad access to the field of oncology and have already shown most promising preliminary results in patients with MRCC. Of mayor interest are antibodies and (receptor) tyrosine kinase inhibitors that are targeted against growth-factor receptors (of vascular endothelial and/or tumor cells). Single or multi-drug regimens are under way and are soon to be marketed.

Infiltration of both T cells and neutrophils in the skin is accompanied by the expression of endothelial leukocyte adhesion molecule-1 (ELAM-1): an immunohistochemical and ultrastructural study.

Various inducible adhesion molecules on human endothelial cells like the endothelial leukocyte adhesion molecule-1 (ELAM-1) seem to be the basis of mechanisms that allow peripheral blood leukocytes to enter precisely areas of inflamed tissue. Because in vitro data had shown that ELAM-1 plays a central role in neutrophil as well as memory T-cell endothelium interactions, we analyzed in vivo at the light and electron microscopic level its expression in various benign and malignant skin diseases, which differ in the composition of the cellular infiltrates. The expression of ELAM-1 on endothelial cells at different anatomical sites could be demonstrated independently from the cell type (neutrophils/memory T cells) infiltrating the surrounding tissue. On the ultrastructural level we demonstrate that the expression of ELAM-1 is restricted to certain segments of post-capillary venules exhibiting distinctive morphologic features. The ELAM-1-positive endothelia are identical to those vessels that are currently described to be the preferred sites of lymphocyte trafficking in diseased skin.

Differential effects of neurotoxic destruction of descending noradrenergic pathways on acute and persistent nociceptive processing.

Although many pharmacological studies indicate that bulbospinal noradrenergic projections contribute to antinociception, lesions of the major brainstem noradrenergic cell groups have provided conflicting evidence. Here we used a new immunotoxin, anti-dopamine beta-hydroxylase-saporin, to re-examine the contribution of noradrenergic pathways to nociception and to morphine analgesia. We treated rats intrathecally by lumbar puncture with the immunotoxin and examined dopamine beta-hydroxylase (DbetaH) immunoreactivity seven and 14 days after treatment. There was no change in DbetaH staining at 7 days; however, 14 days after treatment we demonstrated significant destruction of noradrenergic neurons in the locus coeruleus and in the A5 and A7 cell groups. There was a concomitant loss of noradrenergic axons in the dorsal and ventral horns of the lumbosacral and cervical cord. Consistent with the lack of anatomical changes, we found no difference in nociceptive responses in the hot-plate, tail-flick or formalin tests one week post-toxin. On day 14 we examined the behavioral response to injection of formalin into the hindpaw and found that responses during the second phase of pain behavior were significantly reduced. There was no change during the first phase. Formalin-evoked fos expression in the spinal cord was also reduced. We also evaluated morphine analgesia in the formalin test and found that toxin-treated animals exhibited enhanced morphine analgesia. These results establish the utility of using this immunotoxin to selectively destroy subpopulations of noradrenergic cell groups and provide evidence that acute and persistent nociception are differentially regulated by descending noradrenergic pathways.

Spinal cord mechanisms of opioid tolerance and dependence: Fos-like immunoreactivity increases in subpopulations of spinal cord neurons during withdrawal [corrected].

Tolerance to the analgesic effects of morphine results in part from the development of a compensatory response in neurons that express the opioid receptor or of neural circuits in which those neurons participate. According to this formulation, withdrawal of morphine results in an overshoot of several neuronal properties because of the unopposed action of the compensatory response system. To identify the population of spinal cord neurons that underlies this state, we monitored expression of Fos-like immunoreactivity, after naltrexone-precipitated abstinence in normal and morphine-tolerant rats. After daily (five days) implantation of morphine or placebo pellets, the rats received an injection of saline or naltrexone and behavior was monitored for 1 h. The rats were then killed, their spinal cords removed and 50-microns transverse sections of the lumbar cord were immunostained with a rabbit polyclonal antiserum directed against Fos. Naltrexone injection in the placebo group did not increase spinal cord Fos expression. Naltrexone-precipitated abstinence resulted in an increase in Fos expression at all levels of the spinal cord; the greatest increase and densest staining was in laminae I through VI. Importantly, when withdrawal was precipitated in anesthetized rats, we recorded a significant reduction in Fos expression, particularly in laminae III through VI, but there was persistent expression in the superficial dorsal horn, particularly in lamina I. These results suggest that spinal cord nociresponsive neurons are sensitized during the development of tolerance. This sensitization is unmasked by the administration of naltrexone and is manifested by fos induction in laminae I/II in awake or anesthetized withdrawing animals. The underlying mechanisms of tolerance development may be similar to those that underlie injury-induced central sensitization and hyperalgesia.

The contribution of supraspinal, peripheral and intrinsic spinal circuits to the pattern and magnitude of Fos-like immunoreactivity in the lumbar spinal cord of the rat withdrawing from morphine.

Withdrawal from morphine evokes increases in Fos-like immunoreactivity in the spinal cord, particularly in the superficial dorsal horn, laminae I/II. To determine the origin of the increased Fos-like immunoreactivity, we selectively targeted central or peripheral opioid receptors with naloxone-methiodide, an antagonist that does not cross the blood-brain barrier, or induced withdrawal after eliminating possible sources of input to the superficial dorsal horn. To induce tolerance, we implanted rats with morphine or placebo pellets (75 mg, six pellets over three days). On day 4, withdrawal was precipitated and after 1 h, the rats were killed, their spinal cords removed and 50 microm transverse sections of the spinal cord immunoreacted with a rabbit polyclonal antiserum directed against the Fos protein. In placebo-pelleted rats, none of the different procedures, viz. spinal transection, unilateral dorsal rhizotomy (L4-S2), neonatal capsaicin treatment or direct intrathecal opioid antagonist injection, induced expression of the Fos protein. However, both spinally transected and rhizotomized withdrawing animals showed significant increases in Fos-like immunoreactivity in laminae I/II, compared to intact withdrawing rats. Neonatal treatment with capsaicin, which eliminates C-fibres, did not alter Fos-like-immunoreactivity. Selective withdrawal of morphine from peripheral opioid receptors by naloxone-methiodide did not induce Fos-like immunoreactivity in the lumbar spinal cord greater than that recorded in nonwithdrawing rats. However, intrathecal injection of naloxone-methiodide increased Fos-like immunoreactivity in laminae I/II and the ventral horn to a greater extent than did subcutaneous injection of naloxone. We hypothesize that the increased Fos expression after systemic withdrawal in spinally-transected rats results from a loss of descending inhibitory control that is activated during withdrawal. The increase in withdrawal-induced Fos-like immunoreactivity after rhizotomy may be secondary to loss of inhibitory controls exerted by large diameter primary afferents or to deafferentation-induced reorganization in the dorsal horn. Since capsaicin did not alter the magnitude of Fos-like immunoreactivity in withdrawing rats, we conclude that hyperactivity of opioid receptor-laden C-fibres is not a necessary contributor to the withdrawal-induced increase in Fos-like immunoreactivity in laminae I and II. Taken together with the results recorded after intrathecal injection of naloxone-methiodide in tolerant rats, we conclude that the pattern of lumbar spinal cord Fos expression following systemic withdrawal is primarily a consequence of increased activity in opioid receptor-containing circuits intrinsic to the dorsal horn and that the magnitude of Fos expression is normally dampened by supraspinal and primary afferent-derived inhibitory inputs.

The efficacy of 2',2'-difluorodeoxycytidine (gemcitabine) and vinblastine combined with interferon in nude mice xenografts of human renal cell carcinoma.

Recent in vitro experiments indicated strong activity of 2',2'-difluorodeoxycytidine (dFdC, gemcitabine) in human renal cell carcinoma (RCC) cell lines and an increase of efficacy by combined application of interferon (IFN). In the present study, nude mice with xenografts from ACHN- or SN12C cells were treated by dFdC, dFdC plus IFN-alpha or vinblastine (VBL) plus IFN-alpha. ACHN-xenografts were significantly more inhibited by dFdC+/-IFN-alpha than by VBL+IFN-alpha. Complete remissions (CR) were only seen by dFdC. An additional treatment with IFN-alpha shortened the time to commencement of tumor remission and increased CR of ACHN- and SN12C-tumors (40%; 7%) compared to a treatment with dFdC alone (20%; 0). dFdC+IFN-alpha reduced the number of pulmonary metastases compared to untreated animals. Survival was significantly prolonged by dFdC+/-IFN-alpha in ACHN-mice and dFdC+IFN-alpha or VBL+IFN-alpha in SN12C mice. In conclusion, experimental data confirm dFdC as a superior drug against human RCC compared to VBL. Combined therapy with IFN-alpha increased the efficacy of dFdC in terms of tumor response in immunodeficient nude mice, thus clinical studies are strongly recommended in patients with metastatic renal cell carcinoma.

The efficacy of 2',2'-difluorodeoxycytidine (gemcitabine) combined with interferon in human renal cell carcinoma cell lines.

The present in vitro study on three human renal cell carcinoma (RCC) cell lines (A-498, ACHN, SN12C) evaluated the efficacy of 2',2'-difluorodeoxycytidine (dFdC, gemcitabine), vinblastine (VBL), rhu-interferon-alpha (IFN-alpha) and rhu-interferon-gamma (IFN-gamma) alone or in combinations. The cytotoxicity was measured by using the sulphorhodamine B colorimetric cytotoxicity assay. Analyses were made from cells being continuously long-term (4 weeks) or short-term (4 h) with IFN-alpha or IFN-gamma with regard to the cytotoxicity of the chemotherapeutic agents. dFdC was more cytotoxic against ACHN and A-498 cells compared to VBL. Pre-treatment with IFN-alpha enhanced growth inhibition caused by dFdC (4/4 cell lines) and VBL (2/3 cell lines), and was more effective than IFN-gamma. Pre-exposure with IFN-alpha sensitized SN12C and ACHN cells for dFdC. A-498 cells achieved a decreased sensitivity to dFdC and VBL after pre-exposure to IFN-gamma. The resistance of newly established dFdC-resistant SN12C cells (23-times) decreased when pre-treated with IFN-alpha. The data demonstrate efficacy of dFdC in human RCC at concentrations below clinically achievable doses. dFdC was more effective compared to VBL. Combined therapy preferentially with IFN-alpha increased cytotoxicity of dFdC in vitro. In vivo studies in nude mice xenografts are under investigation to support these observations.

Interferon-alpha and gemcitabine (2',2'-difluorodeoxycytidine) in adult and pediatric renal tumors.

2',2'-difluorodeoxycytidine (dFdC) is an active anticancer drug in different human malignancies. The present study aimed to evaluate if the activity of dFdC in renal tumors could be improved by interferon-alpha (IFN-alpha). The influence of IFN-alpha (4 h) on the cytotoxicity of dFdC was analyzed in vitro by a colorimetric assay. in vivo, nude mice with xenografts from human nephroblastoma (AC-KLxe-12) and renal cell cancer (ACHN, SN12C) were treated by dFdC +/- IFN-alpha. IFN-alpha alone resulted in no growth inhibition in vitro, but pretreatment with IFN-alpha sensitized SN12C and ACHN cells against dFdC. The additional treatment with IFN-alpha increased the CR rate of ACHN- and SN12C-mice (40%; 7%) compared to dFdC alone (20%; 0%). Xenografts from AC-KLxe-12 did all progress. In conclusion, IFN-alpha increased cytotoxicity of dFdC in vitro and tumor responses of renal cell cancer (RCC) in xenografts. Since therapy lacked activity in nephroblastoma, further studies should focus on RCC to compare the efficacy of dFdC and interferons with other types of biochemotherapy.

Language acquisition in the absence of explicit negative evidence: how important is starting small?

It is commonly assumed that innate linguistic constraints are necessary to learn a natural language, based on the apparent lack of explicit negative evidence provided to children and on Gold's proof that, under assumptions of virtually arbitrary positive presentation, most interesting classes of languages are not learnable. However, Gold's results do not apply under the rather common assumption that language presentation may be modeled as a stochastic process. Indeed, Elman (Elman, J.L., 1993. Learning and development in neural networks: the importance of starting small. Cognition 48, 71-99) demonstrated that a simple recurrent connectionist network could learn an artificial grammar with some of the complexities of English, including embedded clauses, based on performing a word prediction task within a stochastic environment. However, the network was successful only when either embedded sentences were initially withheld and only later introduced gradually, or when the network itself was given initially limited memory which only gradually improved. This finding has been taken as support for Newport's 'less is more' proposal, that child language acquisition may be aided rather than hindered by limited cognitive resources. The current article reports on connectionist simulations which indicate, to the contrary, that starting with simplified inputs or limited memory is not necessary in training recurrent networks to learn pseudonatural languages; in fact, such restrictions hinder acquisition as the languages are made more English-like by the introduction of semantic as well as syntactic constraints. We suggest that, under a statistical model of the language environment, Gold's theorem and the possible lack of explicit negative evidence do not implicate innate, linguistic-specific mechanisms. Furthermore, our simulations indicate that special teaching methods or maturational constraints may be unnecessary in learning the structure of natural language.

Studies on a radioassay for intrinsic factor antibody: comparison of methods and false positive results due to elevated serum B12 levels.

Availability of a kit method (Corning Immo Phase IFAB) for intrinsic factor antibody (IFAB) has made it possible for a routine radioimmunoassay (RIA) laboratory to test for the antibody, thereby providing another aid in diagnosing pernicious anemia. Comparison of data from a charcoal method with the kit method was favorable, each method detecting 35 (74%) positives and 12 (26%) negatives of 47 pernicious anemia patients. Compared with a charcoal method study the kit method had fewer false positives due to elevated serum B12. False positive results occurred for only 24 hours after a 1-mg injection of B12, and results remained negative the following seven days. The authors' studies supported the manufacturer's statement that results are unreliable when the serum B12 level exceeds 3,500 pg/ml. Clinical experience with the Corning Immo Phase IFAB test and false positive results is summarized.

A simple route to N-arylated 2-aminothiophenes as a new class of amorphous glass forming molecules.

By thermal decarboxylation of N-arylated 2-aminothiophene-5-cacrboxylates, a versatile, heavy-metal free method for preparing the title compounds as new class of highly reactive and easily oxidable, amorphous glass forming molecules has been elaborated.

Cytokine release by human bone marrow cells: analysis at the single cell level.

Regulation of haemopoiesis is closely mediated by a number of growth factors in the marrow microenvironment. The identification of the cell type secreting these regulatory polypeptides is difficult due to the heterogeneity of bone marrow cells. To analyse the release of haemopoietic growth factors by normal human bone marrow cells at the single cell level, we employed the reverse haemolytic plaque assay (RHPA). Freshly isolated human marrow cells were examined for the release of interleukin-1 alpha (IL-1 alpha), IL-3, IL-6 and granulocyte-monocyte colony stimulating factor (GM-CSF). In order to identify various cytokine-secreting cell types, the RHPA was combined with immunocytochemical or enzymatic staining. The total of secreting marrow cells as well as the amount of several secretory haemopoietic subpopulations could be determined with this technique under various conditions. Following incubation with pure serum-free medium without addition of any mediator, only few cells secreting either IL-1 alpha, IL-3, IL-6 or GM-CSF could be observed. After 2 h incubation with recombinant human-IL-1 alpha (rhIL-1 alpha) (10.0 ng/ml) or rhGM-CSF (10.0 pg/ml) the number of cytokine-secreting cells significantly increased for all secretory products tested. Using cytochemical staining reactions, we were able to identify 55% of all cells secreting a specific cytokine. Glycophorin C-positive erythropoietic cells turned out to be the largest fraction (up to 89%) of cytokine-releasing haemopoietic cells, followed by neutrophil granulocytes (between 6 and 48%), and monocytes/macrophages (between 4 and 23%). Only few CD 61-positive cytokine-secreting megakaryocytes could be detected. Dose- and time-dependent kinetics after stimulation with rhGM-CSF revealed that the bulk of secretory activity originates from haemopoietic or rather from erythropoietic cells following low level stimulation and after short stimulation time. Thus, our data are in keeping with the assumption, that especially erythropoietic cells are producing a repertoire of cytokines that is thought to exhibit regulatory functions within marrow microenvironment. In the present study the RHPA is presented as an appropriate tool for measuring cytokine release not only of cells of the haematopoietic system but also of other tissues, for example solid tumours or malignant lymphomas.