Unmanipulated peripheral blood stem cell autograft in chronic lymphocytic leukemia: clinical findings and biological monitoring

BACKGROUND AND OBJECTIVES

To investigate the feasibility of peripheral blood stem cell (PBSC) transplantion in patients with high-risk chronic lymphocytic leukemia (CLL) in remission after fludarabine therapy, the clinical impact of minimal residual disease (MRD) monitoring and the immunologic reconstitution after transplantation.

DESIGN AND METHODS

Twenty CLL patients, in clinical complete remission (CR) after fludarabine, were offered an unmanipulated PBSC transplant and were longitudinally monitored for MRD and immunologic reconstitution.

RESULTS

Due to unsatisfactory PBSC collection, 4 patients received bone marrow cells. All patients engrafted. Two patients died, one due to infection and one because of another neoplasia. Thirteen patients are at present in clinical CR after a median follow-up of 17 months and 18 patients are alive with a survival probability of 0.87 (+/-0.04) at 52 months after transplant. Fifteen patients had a molecular remission. Three of them showed a molecular relapse 16-28 months after autograft, followed by a clinical relapse 10-16 months later. Three of the four patients who remained persistently rearranged could be revaluated over time and showed an immunologic relapse 11-26 months after transplant; two of these had a clinical relapse 12 and 7 months later. A marked and persistent impairment of both the B- and T-immunologic compartments was recorded in the horizontal follow-up.

INTERPRETATION AND CONCLUSIONS

Unmanipulated PBSC autograft is a feasible procedure that produces prolonged molecular remissions in high-risk CLL patients. Persistence or reappearance of a molecular signal after engraftment is predictive of subsequent immunologic and clinical CLL recurrence. The long -lasting impairment of the host immune repertoire after fludarabine followed by autograft has to be taken into account in the patients' management.

Schedule dependent toxicity and efficacy of combined gemcitabine/paclitaxel treatment in mouse adenocarcinoma

Increased interest in combining drugs with different targets has emerged over recent years. Our study aims at evaluating the effectiveness of combined gemcitabine/paclitaxel treatment taking into consideration doses, schedules, and toxicity. A spontaneous mammary carcinoma was transplanted into the right-hind foot of C3D2F1 mice. Paclitaxel (in doses from 20 to 80 mg/kg b.w.) and gemcitabine (in doses from 30 to 480 mg/kg b.w.) were administered i.p. in single or fractionated treatments. Toxicity and tumor growth delay (TGD) were the endpoints. TGDs for different gemcitabine doses in single administration (120, 240, and 360 mg/kg) overlapped (TGD approximately = 2.5 days). Toxicity was very high in daily administration. Results with gemcitabine alone showed the efficacy of treatments every 3 days. TGDs in fractionated treatments of 60 and 120 mg/kg x 4 were of approximately equals 16 days. Also in this case, tumor growth curves overlapped pointing out the uselessness of the high drug doses. For combined treatments, we used only fractionated protocols, administering gemcitabine every 3 days. Paclitaxel was administered alone in one or two fractions and with different sequences in respect to gemcitabine administration. With 120 mg/kg of gemcitabine all the protocols showed an increased unacceptable toxicity. The best result was obtained administering paclitaxel 40 mg/kg on days 1 and 15 and gemcitabine 60 mg/kg on days 3, 6, 9, and 12 (TGD = 38.2 days). The light toxicity and the high efficacy obtained with this protocol indicate the possible use of gemcitabine/paclitaxel treatment in clinical practice.

Health status and internal radiocontamination assessment in children exposed to the fallout of the Chernobyl accident

The Chernobyl fallout caused release of radioisotope contaminants in a very large area that includes Belarus, the Ukraine, and the Russian Federation. In this study, the authors monitored the health status and level of internal contamination in 422 children who resided in the aforementioned areas and who were < or = 10 y of age at the time of the accident. The children came to Italy for a 1-mo period between 1991 and 1992. During this time, the children underwent pediatric checkups and biochemical, immunological, and thyroid analyses. All children underwent whole-body counter measurements, and urine radiotoxicological analysis was performed for 224 of them. The 24 children evacuated from Pripiat, a village very close to the Chernobyl reactor site, were selected for cytogenetic analysis. All of these children continue to have a detectable internal contamination of caesium radioisotopes. This condition is likely the result of ground and foodstuff contamination in the various areas. The children did not evidence overt pathologies related to ionizing radiation. However, minor alterations in immunological and thyroid parameters were observed in the group of the evacuated children. Traditional cytogenetic dosimetry was not possible, but the occurrence of acentric fragments was observed-indicating a persistent effect of continuous exposure to low doses of radiation.

Treatment of squamous cell anal canal carcinoma with pulsed dose rate brachytherapy. Feasibility study of a French cooperative group

BACKGROUND AND PURPOSE

To evaluate the feasibility of pulsed dose rate (PDR) brochytherapy in squamous cell anal canal carcinoma (SCACC).

MATERIALS AND METHODS

In this study a series of 19 patients with SCACC were included between 1995 and 1997. All patients were treated with curative intent with external beam radiotherapy (EBRT) (44-50 Gy) and one or two cycles of concomitant fluorouracilcisplatinum. After a gap of 2-3 weeks PDR interstitial brachytherapy was performed with a rigid needles technique. The dose was between 10-25 Gy (PARIS system).

RESULTS

All patients are alive. No severe grade 3-4 toxicity was encountered. One local relapse one metastatis were seen in two distinct patients. There was no dysfunction of the after loading machine.

CONCLUSION

The feasibility of PDR brachytherapy appears good in SCACC. It is an attractive alternative to low dose rate brachytherapy.

IL4 production and increased CD30 expression by a unique CD8+ T-cell subset in B-cell chronic lymphocytic leukaemia

Phenotypic and functional abnormalities within the residual non-B-cell compartment of B-cell chronic lymphocytic leukaemia (CLL) suggest an interaction between tumour cells and host immune effectors. To explore the possibility of a polarized Th1/Th2 response we have studied CD30 antigen expression and the pattern of cytokine production by purified CLL T cells. Activated T cells from CLL patients showed a significant increase in the expression of CD30 compared to normal controls. Accordingly, high levels of soluble CD30 were detected in supernatants from activated T-cell cultures, as well as in CLL serum samples. Messenger RNA for IL4 was found in both resting and, to a greater extent, in activated CLL T lymphocytes. The latter cells were also capable of releasing IL4. Three-colour immunofluorescence analyses revealed a strong CD30 expression in the CD3+/CD8+/CD28- large granular lymphocyte subset, which is considerably expanded in CLL. Production of IL4, as well as expression and release of CD30 by these T cells, was conclusively demonstrated at the clonal level. These findings document an expansion of a peculiar subset of 'Th2-like' cells in CLL, with an increased IL4 production and CD30 expression and release, that are likely to contribute to both the B-cell accumulation and immune-defects characteristic of this disease.

Morphological variation analysis of the repeatability of soccer offensive schemes

A landmark-based statistical method, morphological variation analysis, for the quantification of the repeatability in the arrangement of body segments during the execution of sport actions has recently been developed. A two-dimensional shape is produced and its morphology is studied. The method was used to measure the within-team variability of the relative positions of players during the execution of offensive schemes in soccer. Two junior soccer teams of different technical abilities (semi-professional vs. amateur), each playing two standardized offensive schemes of different difficulty (easier: throw-in; more difficult: wing attack) were filmed. Each scheme was repeated 25 (semi-professionals) or 10 (amateurs) times. For each repetition, the position of the players in a single significant frame was analysed using morphological variation analysis. The reproducibility of both schemes was higher among the semi-professionals than among the amateurs (two-way analysis of variance, P<0.005). The repeatability of the players' relative positions was related to the difficulty of the scheme and the technical level of the team. Among the amateurs, the throw-in was more reproducible than the wing attack (Student's t-test, P<0.005). The method not only allows the quantification of collective (team) coordination, but also the separation of the influence of individual players.

Cytogenetic study on children living in Southern Urals contaminated areas (nuclear incidents 1948-1967)

As a result of the activities of the first Soviet plutonium production reactor, large territories of the Southern Urals were exposed to radioactive contamination. Three different incidents occurring between 1948 and 1967 lead to major exposure. A total of 280,000 people residing on the contaminated territories were exposed both to external and internal contamination particularly due to the long-lived radionuclides 137Cs and 90Sr. The highest doses were received by 28,000 people living on the Techa riverside villages. In the present paper 15 presumably exposed children coming from the Muslyumovo village on the Techa river have been analyzed using conventional cytogenetic procedure in order to assess a radiation-induced damage. The data obtained have been compared to a group of matched unexposed controls. The results show a statistical difference between the two cohorts which suggests a possible residual contamination representing a continuous hazard for the new generations.

Insulinlike growth factor 1 in controls and growth-retarded fetuses

OBJECTIVES

To establish a reference range of insulinlike growth factor 1 (IGF-1) values in normal fetuses and to assess whether intrauterine growth retardation is associated with increased or decreased IGF-1 levels.

METHODS

Retrospective analysis of blood samples collected from 64 fetuses who underwent blood sampling at 18-38 weeks' gestation was performed: 40 fetuses, who were considered controls, were appropriately grown for gestational age and were found unaffected by the condition for which they were tested; the remainder (n = 24) underwent fetal blood sampling to assess fetal karyotype and acid-base balance following ultrasonic diagnosis of intrauterine growth retardation. (In this group, 8 survived, and 16 died during the perinatal period). IGF-1 was measured using a radioimmunoassay after acid-ethanol extraction in order to avoid interference by the binding proteins. All samples from controls and growth-retarded fetuses were measured using the same batch, and the intra-assay coefficient of variation of the test ranged from 4.1 to 6.1%.

RESULTS

In control fetuses, IGF-1 serum levels increased linearly with gestational age. In growth-retarded fetuses, IGF-1 levels were not significantly different from the reference range (median Z-score -0.3; range -4.4 to 291) and did not correlate with fetal size, hematocrit, and acid-base balance values. There was a significant difference in IGF-1 and pH values when the fetuses were divided into two groups based on the perinatal outcome: those who survived had values of IGF-1 mostly within the normal range, whereas the fetuses who died in utero or postnatally had significantly decreased pH and elevated IGF-1 values (median Z-score 2.1; 95% confidence interval 0.4-13.9; p = 0.04).

CONCLUSIONS

This study confirms previous observations that IGF-1 levels parallel the increase in fetal size which occurs with advancing gestation. Increased levels of IGF-1 may indicate a terminal process in the fetal adaptation to placental failure.

Cytogenetic effects in lymphocytes from children exposed to radiation fall-out after the Chernobyl accident

In a previous paper we reported that a group of children exposed to ionizing radiation following the Chernobyl accident exhibited an appreciable number of chromosome breaks and rearrangements reflecting the persistence of a radiation-induced damage. The results suggested that the children were still exposed to radioactive contamination through consumer foodstuff and life styles. In the present paper, 31 exposed children have been considered together with a control group of 11 children with the aim to confirm previous results. All children underwent whole-body counter (WBC) measures and conventional cytogenetic analysis. The frequency of chromosome aberrations detected by conventional cytogenetics in the group of children chronically exposed to low doses of ionizing radiation resulted in significant differences with respect to the control group. The present work suggests that, for these groups of children, even if the frequency of aberrations is very low and the observation of statistically significant differences is consequently a problem, a persistently abnormal cytogenetic picture is still present several years after the accident.

Do human lymphocytes exposed to the fallout of the Chernobyl accident exhibit an adaptive response? III. Challenge with bleomycin in lymphocytes from children hit by the initial acute dose of ionizing radiation

In the present paper, we report data on the possible adaptive response, induced in vivo by exposure to ionizing radiation to a challenge treatment with the radiomimetic glycopeptide bleomycin (BLM). Lymphocytes from children living in Pripjat at the time of the Chernobyl accident, and thus hit by the initial acute dose of ionizing radiation, were treated for the last 5 h of culture with 0.004 U/ml BLM. Significantly lower chromosome damage was found only in lymphocytes from children who, independently of the initial acute exposure to ionizing radiation, still showed a 137Cs internal contamination, due to persistent continuous exposure to low doses of radiation. The present results indicate that past exposure to acute high dose of ionizing radiation does not interfere with resistance to BLM which is related to internal contamination.

Laparoscopic uterine biopsy for diagnosing diffuse adenomyosis

OBJECTIVE

To investigate the possibility of diagnosing diffuse adenomyosis with the uterus in situ.

STUDY DESIGN

Myometrial needle biopsy was performed on a prospectively evaluated series of 72 women undergoing laparoscopy for infertility and/or chronic pelvic pain. Before surgery the patients completed a questionnaire on the presence and severity of dysmenorrhea according to a linear analog and verbal rating scale. A single specimen was taken from along the median line in the upper third of the posterior uterine wall using a 14-gauge Tru-cut needle inserted through the anterior abdominal wall under laparoscopic guidance.

RESULTS

No complications occurred. Adenomyosis was diagnosed in 8 of the 42 subjects with menstrual pain and 5 of the 30 asymptomatic ones (19% versus 17%) and pelvic endometriosis in 27 and 10, respectively (64% versus 33%, P = .02). The frequency of moderate or severe dysmenorrhea was greater in women with adenomyosis than in those without adenomyosis or endometriosis, but the difference was not statistically significant. Conversely, menstrual pain was significantly more frequent and severe in patients with endometriosis as compared with women who had neither endometriosis nor adenomyosis.

CONCLUSION

Uterine needle biopsy is simple, rapid and safe, but its overall clinical importance, as well as the predictive value of a normal histologic result, requires further investigation.

Do human lymphocytes exposed to the fallout of the Chernobyl accident exhibit an adaptive response? 2. Challenge with bleomycin

The present study concerns the possible adaptive response, induced in vivo by a continuous exposure to ionizing radiations, to a challenge treatment with the radiomimetic glycopeptide bleomycin (BLM). Lymphocytes from children contaminated as a consequence of Chernobyl accident were treated for the last 5 h of culture with 2.5 micrograms/ml BLM. The induced chromosome damage was significantly lower than that found with the same treatment in lymphocytes from control children. This hyposensitivity to BLM was still present if, 1 h after the addition of the drug, inhibitors of the enzymes involved in DNA repair, such as 3-aminobenzamide (2 mM), or aphidicolin (0.4 microM) or 3-dideoxythymidine (5 mM) were added to the cultures. The resistance to BLM in lymphocytes from contaminated children seems to be related to a mechanism upstream in respect to the activities of enzymes involved in the DNA repair and specifically linked to the action of this drug. This is consistent with the different response found when the cells were challenged with ionizing radiation in vitro, as reported in the accompanying paper (L. Padovani, L. et al. (1995) Mutation Res., this issue).

Do human lymphocytes exposed to the fallout of the Chernobyl accident exhibit an adaptive response? 1. Challenge with ionizing radiation

Several studies suggest that cells appear to become less susceptible to the induction of radiation damage, and in particular of chromosome and chromatid aberrations in short-term cultures of human lymphocytes, when a challenge exposure to ionizing radiation is preceded by a low 'adaptive' dose. Contradictory results have been reported on the conditions under which the phenomenon can be evidenced. In the present work, circulating lymphocytes of 13 children contaminated from the fallout after the Chernobyl accident were tested for their capability to exhibit an adaptive response in experiments in which the challenge dose was administered to stimulated lymphocytes in the S-G2 phase. Furthermore, the possible influence of 3-aminobenzamide, an inhibitor of poly(ADP-ribose) polymerase, was also investigated. Our results indicate that, at least in the instance of the end-point here used (chromosome and chromatid aberrations, the former resulting possibly from the Cs burden), human lymphocytes, chronically exposed to low doses from fallout, do not exhibit any decreased susceptibility to ionizing radiation. However, as reported in the accompanying paper, the same samples appear to show an 'adaptive' response when exposed to a challenge treatment with bleomycin (B. Tedeschi et al., 1995, this issue).

Very low dose danazol for relief of endometriosis-associated pelvic pain: a pilot study

OBJECTIVES

To evaluate the efficacy and safety of very low dose danazol in improving pelvic pain in women with endometriosis, the benefit of preceding the treatment by a short course of a GnRH agonist, symptoms recurrence after drug withdrawal, and variations in menstrual pattern.

DESIGN

Open-label, randomized study.

SETTING

University hospital endometriosis center.

PATIENTS

Forty-two women with moderate or severe pelvic pain and laparoscopically diagnosed endometriosis.

INTERVENTIONS

Treatment with oral danazol, 50 mg/d, for 9 months (group I, n = 21) or leuprolide depot for 3 months followed by oral danazol, 50 mg/d, for 6 months (group II, n = 21), and a 6-month follow-up.

MAIN OUTCOME MEASURES

Variations in severity of symptoms during treatment and at the end of follow-up as shown by a linear analog scale and a verbal rating scale; menstrual blood loss as assessed by a pictorial chart.

RESULTS

Four patients withdrew from the study, one in each group at the fifth month of treatment (for persistent pain) and one in each group during follow-up (they requested additional therapy); one woman in group I was lost to follow-up. Significant improvements were obtained in dysmenorrhea, deep dyspareunia, and nonmenstrual pain in both treatment schedules without differences between the groups. Also menstrual blood loss was significantly reduced in both groups. A temporary fall in high and rise in low density lipoprotein cholesterol was observed in the study population. At the end of follow-up symptoms recurred without significant differences in median pain scores with respect to baseline.

CONCLUSION

Very low dose danazol may be an alternative for temporary relief of endometriosis-associated pain. Ovulation is not always inhibited and barrier contraception is needed. Side effects occur but are rarely severe. Further data are required to evaluate the influence of long-term administration on the lipid profile.

Paracervical anesthesia for outpatient hysteroscopy

One hundred seventy-seven women aged 41 +/- 8 (mean +/- SD) years, referred for evaluation of excessive uterine bleeding, were enrolled in an open-label randomized trial to evaluate the efficacy of local anesthesia before hysteroscopy in an outpatient population. The patients underwent hysteroscopy and endometrial biopsy with paracervical block by 10 mL of 1% mepivacaine hydrochloride solution (n = 87) or no local anesthesia (n = 90) and assessed lower abdominal and pelvic pain according to a 10-point linear analog scale. The mean +/- SD pain score was 4.5 +/- 2.0 at hysteroscopy and 5.2 +/- 2.1 at endometrial biopsy in the 87 subjects given a paracervical block versus 4.9 +/- 2.2 and 5.7 +/- 2.4 in the 90 women not given local anesthesia, without statistically significant differences. Paracervical anesthesia for routine outpatient hysteroscopy in premenopausal women may be superfluous.

Gonadotropin releasing hormone agonist treatment before hysteroscopic endometrial resection

OBJECTIVES

To evaluate the effects of treatment with the gonadotropin releasing hormone (GnRH) agonist goserelin before endometrial resection on absorption of distension medium fluid and technical feasibility of the surgical procedure.

METHODS

Fifty-five patients reporting menorrhagia underwent endometrial resection after 2 months of goserelin depot therapy (33 cases) or during the proliferative phase of the cycle (22 controls).

RESULTS

In the cases, the mean distension medium deficit +/- S.D. was 511 +/- 196 ml versus 647 +/- 245 ml in controls (P = 0.03), and the operating times were, respectively, 14 +/- 4 versus 18 +/- 5 min (P = 0.002). The intrauterine operating conditions were considered excellent or good in 64% of the cases versus 27% of the controls (chi 2 = 5.60, P = 0.02).

CONCLUSIONS

GnRH agonists induce endometrial thinning, so that when administered before intrauterine interventions, mucus cellular debris and bleeding should be reduced during surgery and hysteroscopic visibility increased; the operating time may thus be shorter and fluid absorption decreased. However, more data are needed before considering GnRH agonists a proven effective means of facilitating endometrial resection.

Cytogenetic study in lymphocytes from children exposed to ionizing radiation after the Chernobyl accident

The present study concerns the monitoring of children from the Byelorussian, Ukrainian and Russian republics exposed to the fall-out of the Chernobyl accident. Cytogenetic analyses have been performed on 41 children coming from different areas and exhibiting varying amounts of 137Cs internal contamination, as evaluated by whole-body counter (WBC) analysis. On a total of 28,670 metaphases scored, radiation-induced chromosome damage is still present, although at a very low frequency. Due to the very low fraction of dicentrics, because of the time elapsed from the accident and the relatively low doses of exposure, radiobiological dosimetry is not possible for these children. However, considering that the WBC data indicate that the children are still exposed to 137Cs contamination, the observed occurrence of stable chromosome rearrangements and breaks may represent the persisting effect of continuous low doses of radiation. The present study also indicates that the parallel use of internal contamination dosimetry and cytogenetics could be usefully employed to monitor individual exposure to radiation and to define further management measures.

Adhesion molecule expression on B-cell chronic lymphocytic leukemia cells: malignant cell phenotypes define distinct disease subsets

Expression of surface adhesion molecules of the Ig superfamily (CD54 and CD58), of the integrin family (beta 1, beta 2, and beta 3 chains), of the selectin family (L-selectin), and of the lymphocyte homing receptor (CD44) was analyzed on B-cell chronic lymphocytic leukemia (B-CLL) cells from 74 patients. The aim of the study was the definition of phenotypically distinct disease subsets and the correlation of adhesion molecule phenotypes with clinical parameters. Expression of CD58 on B-CLL cells defined more advanced disease stages. In comparison with beta chain-positive cases, patients whose cells did not express beta 1, beta 2, and beta 3 integrin chains fell into the most favorable prognostic group, with lower lymphocytosis and the absence of splenomegaly, diffuse bone marrow infiltration, and therapy requirement. A novel finding was the expression of beta 3 chains on cells from a minority (12 of 74) of B-CLL cases. beta 3 chains were always coexpressed with beta 1 and beta 2 chains. Two-color immunofluorescence analyses of adhesion molecules such as alpha x beta 2 integrin (LeuM5) and L-selectin (Leu8) showed that these markers were detectable on variable proportions of leukemic cells, thus confirming the intraclonal phenotypic heterogeneity of B-CLL. Differences in the intensity of CD44 expression were also shown among the various B-CLL clones. Finally, no major variations were shown by comparison of adhesion molecule phenotypes of leukemic cells simultaneously obtained from blood and bone marrow, and of CD5+ versus CD5- clones.

The importance of heterogeneity and of multiple site sampling in the prospective determination of deoxyribonucleic acid flow cytometry

Multiple fresh specimens from 59 nonsmall cell carcinomas of the lung, 38 carcinomas of the gastric tract and 55 carcinomas of the colon and rectum were analyzed by deoxyribonucleic acid (DNA) flow cytometry (FC) after radical resection to evaluate tumor ploidy as an independent prognostic factor. The minimum follow-up period was five years (range of five to ten years). Aneuploidy was observed in 98.0 percent of carcinomas of the lung, in 70.9 percent of carcinomas of the colon and rectum and in 63.1 percent of carcinomas of the gastric tract. FC DNA heterogeneity, in terms of different number of DNA stem lines or different DNA indices between core and periphery, or both, was found in 50.0 percent of carcinomas of the lung, 47.0 percent of carcinomas of the colon and rectum and in 34.5 percent of carcinomas of the gastric tract. A diploid pattern was more frequently observed in less advanced stages of the gastrointestinal tract. By univariate analysis (Kaplan-Meier), patients with carcinoma of the lung with hypodiploid or hypertetraploid peaks, or both, and aneuploid gastric tumors had poorer prognosis. These differences were only marginally significant. Cox analysis demonstrated that the single most important prognostic variable for predicting the overall survival rate was the stage of disease. Tumor DNA content can be considered a marker of advanced stages, particularly in tumors of the gastrointestinal tract, but there is no evidence that it is an independent prognostic variable able to predict long term survival in patients who have been radically resected.

[Meteoropathy: a syndrome continuously on the increase]

The authors describe the different kinds of meteoropathies, pointing out how these disorders are becoming ever more frequent in countries belonging to the consumer and welfare society due to the progressive lowering of body resistance and immunologic responses. These "unfavourable meteosyndromes", as meteoropathies should be called, develop when wave disturbances arrive, and are more manifest and persistent in subjects with neurologic disturbances, i.e. in the presence of anxiety, stress, hypertension, coronary artery disease, arthropathy, hyperthyroidism, etc. The different moments in which meteoropathies are more frequent and the possible therapies are also discussed.

[Effects of beta blocking agent iontophoresis by modulated sinusoidal current]

The action of the transcutaneous application of propranolol using modulated sinusoidal current iontophoresis was studied. When this way of administration is used, the drug, while maintaining its negative chronotropic effect, loses the negative inotropic one. Investigations were performed on 58 men aged 32 to 62 who underwent an aortocoronary bypass for myocardial ischemia. Thirty-four patients had already had myocardial infarction. The drug reduced the heart rate and increased cardiac contractility. Moreover, the study showed that only the levogyral isomer of propranolol (the only active one) passes through the skin.

Interaction of cytotoxic agents: a rule-based system for computer-assisted cell survival analysis

The actual effectiveness of environmental noxious agents or anticancer drugs can be fully determined only by knowing if the effects (in the present case, the cytotoxic effects) induced by a given agent are enhanced by exposure to another (or other) agent(s). Given a certain combination of agents, it is possible to distinguish three types of interaction: (a) zero interaction or additivity; (b) positive interaction or synergism; and (c) negative interaction or antagonism. In this work, the methodological problems involved in evaluating the type and level of interaction between biologically active agents are discussed and an "intelligent" approach to the problem is proposed. In particular, a prototype of a computer-assisted rule based system, named CISA (Cytotoxic Interaction and Survival Analysis), designed in a KES environment (Knowledge Engineering System) and implemented on a personal computer, is described. By constructing isoboles based on experimental cell survival data and taking into account the relative confidence intervals, the system can indicate the appropriate combinations of dosages to be tested and finally determine the type and level of interaction. The system, which represents an attempt to administer "intelligently" the experimental data, is therefore able to identify the best strategy of analysis, to carry out the data processing and to offer suggestions to the investigator about the usefulness of the data and the planning of further experiments.