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Background Silicone adhesive multilayer foam dressings are used as adjuvant therapy to prevent hospital-acquired pressure ulcers (PUs). Objectives To determine whether silicone foam dressings in addition to standard prevention reduce the incidence of PUs of category 2 or worse compared with standard prevention alone. Methods This was a multicentre, randomized controlled medical device trial conducted in eight Belgian hospitals. At-risk adult patients were centrally randomized (n = 1633) to study groups based on a 1 : 1 : 1 allocation: experimental groups 1 (n = 542) and 2 (n = 545) - pooled as the treatment group - and the control group (n = 546). The experimental groups received PU prevention according to hospital protocol, and a silicone foam dressing on the relevant body sites. The control group received standard of care. The primary endpoint was the incidence of a new PU of category 2 or worse at the studied body sites. Results In the intention-to-treat population (n = 1605), PUs of category 2 or worse occurred in 4·0% of patients in the treatment group and 6·3% in the control group [relative risk (RR) 0·64, 95% confidence interval (CI) 0·41-0·99, P = 0·04]. Sacral PUs were observed in 2·8% and 4·8% of the patients in the treatment group and the control group, respectively (RR 0·59, 95% CI 0·35-0·98, P = 0·04). Heel PUs occurred in 1·4% and 1·9% of patients in the treatment and control groups, respectively (RR 0·76, 95% CI 0·34-1·68, P = 0·49). Conclusions Silicone foam dressings reduce the incidence of PUs of category 2 or worse in hospitalized at-risk patients when used in addition to standard of care. The results show a decrease for the sacrum, but no statistical difference for the heel and trochanter areas.

This paper presents a virtual circuit controller (VCC), which provides a systematic structured method to stabilize the resonance of an LCL filter in a grid-connected voltage source converter. The semiconductor switches are controlled to mimic the behaviour of a virtual reference circuit. The properly-damped circuit by a resistor in parallel with a filter capacitor is focused on and selected as the reference circuit. A linear transformation matrix is introduced indicating the resemblance between the physical and virtual circuits, and is employed to map the states between both circuits. Accordingly both analog and digital control laws are systematically computed. The insight into the feedback of the capacitor current and voltage through proportional gains is clarified. While the consequence of the former is conventionally known to emulate a resistor for damping purpose, the latter is newly used to emulate an inductor for adjusting the inner-loop control bandwidth and improving the robustness. A Kalman filter is used to deal with the inherent time delay. The detailed discrete-time state-space model of the complete system is derived. The design example of the proportional current controller is demonstrated. The simulation results illustrate the effectiveness of the damping and the robustness of the system against component-value variations.

This paper presents a structured design method for half-bridge converters with higher-order lossless output filters, focusing on the popular LCL filters. The method builds on the theory of terminated ladder networks and on a control algorithm actively emulating the ladder network's termination. Given a desired transfer function, a normalized ladder network is accordingly synthesized and scaled to meet the physical requirements. The component sizing and the active damping of filter resonances are simultaneously tackled. The associated digital-control architecture for LCL filters is explained. A Kalman observer is employed to deal with the inherent sample delay. An LCL filter is designed based on the proposed method and is experimentally validated with the half-bridge converters operating as active front end. The grid reactive currents are stepped and the results show properly damped responses. The system has good disturbance rejection and is passive according to the simulated input admittance. The robustness of the system is also demonstrated by numerical sensitivity analysis. These excellent characteristics can facilitate the design of the upper-layer or incorporated outer-loop controller, and can enhance the performance of the complete system.

This paper presents a novel structured design method for actively-damped, lossless, LC-ladder filters of general order. The method builds on the theory of ladder network synthesis and on a control algorithm actively emulating the termination of a ladder network. Given a desired reference transfer function, a normalized ladder network is synthesized and scaled to meet the physical requirements. As such, it simultaneously tackles the design and sizing of the filter, and the active damping of filter resonances. The associated digital-control architecture is also elaborated. The method is applied to designing a 3rd-order LCL filter, of which the experimental results show properly damped responses. Moreover, the design of a 5th-order LCLCL filter is introduced and the result is promising for the applications requiring high bandwidth and/or high attenuation.

De toenemende prevalentie van MRSA in Nederland is een probleem waarmee vooral grensregio's geconfronteerd worden. De unieke geografische ligging van Zeeuws-Vlaanderen heeft geleid tot de noodzaak van een stringent beleid, om verspreiding naar en binnen deze regio terug te dringen. Een belangrijke voorwaarde voor het opzetten van een dergelijk beleid is voorkennis van de MRSA-prevalentie in de regionale zorginstellingen. Dit artikel beschrijft het onderzoek naar de huidige prevalentie in de Zeeuws-Vlaamse zorginstellingen, de organisatie van een regionaal beleid en de resultaten ervan.

In this article, the House of the Italian Tocco is discussed in context with their territories in Greece at the end of the 14th century and during the 15th Century. The authors examine how the Tocco have built up, starting from rather humble beginnings as functionaries, an important territory in Epiros, which they transformed into a medieval 'state', when they were honoured with the dignity of 'Despotes'. The characteristics of their 'state' are analyzed and discussed.

This article gives an overview of the baqt in Nubia, and examines the letter of the Egyptian governor, Musa Ibn Ka'b, to king Kyriakos of Nubia (Makouria and Nobatia). This letter not only brings new knowledge about the baqt and its application, but also generates a number of questions about the baqt itself and the relations between Christian Nubians, Muslim Egyptians and the Bejas. The present article addresses these questions.

This online questionnaire was initiated to investigate if a consensus on the treatment of distal radius fractures amongst orthopaedic surgeons in Belgium exist. Two cases were presented: an extra-articular fracture, with dorsal displacement (Frykman type I) and a displaced intra-articular fracture (Frykman type VII). Treatment of choice and rationale of choice were investigated. 158 responses were collected. In case of a Frykman type I, the majority of surgeons would have performed a closed reduction and intrafocal K-wiring (37.3%) or volar plating (34.8%). In case of a Frykman type VII, volar plating was the primary treatment of choice (66.5%), closed reduction and K-wiring was chosen in 24.7% and external fixation in 4.4%. We cannot conclude on a consensus in treatment choice amongst Belgian orthopaedic surgeons. Compared to previous research, an increase in the use of volar plating in intra- as well as in extra-articular distal radius fractures was noticed.

This article examines the dogmatic-theological and ethical problems put forward in a number of recent bestselling thrillers of which the intrigues are build around Early Christian Apocrypha or/and modern bio-ethics. The discovery and publication of the Gospel of Judas has—in its turn—contributed to and accentuated some of these problems. A number of questions are posed in this article which sharpen the problems, and answers to the questions are also suggested.

In this article the policy of Pope Innocent III on monasteries in the Byzantine territories, occupied by the Latins after the fourth crusade (1204), is examined. The "constitutional" documents relating to church property are discussed as a basis for Innocent's pragmatic attitude and the development of a policy. From the Pope's letters it becomes evident that the pontiff distinguished between 5 categories of 'existing' monasteries (imperial, royal, patriarchal, episcopal and the ones in Athos), while Western orders (especially military ones) are introduced in the Byzantine territory. Finally, Innocent's reaction to the serious problem of lay usurpation is discussed.

This article examines the ‘pact’ between Caliph 'Umar ibn-al-Khattâb and Patriarch Sophronios of Jerusalem (638 AD), comparing it with other similar agreements. It shows that the Caliph's reaction to the Arab conquest of the Holy City was generous and that he does not deserve the qualification of ‘abominatio desolationis’ (Matthew 24.15 and Mark 13.14.). The analysis of different agreements sheds new light on the status of the different Christians ‘denominations’ and on the presence of the early African Churches in Jerusalem.

1. INLEIDEND In 453 n.C. is die reg van die Nubiers om die godin Isis te Pbitae vrylik te aanbid deur Maximinus, die Romeinse generaal in Egipte, erken. Die Bisantynse keiser, Justinianus, bet di~ tempel egter in ca. 540 laat sluit, en die beidense beelde is toe na Konstantinopel oorgebring (Adams 1977:440). Die Nobatae (Nobadae), 'n volkstam wat bom in die noorde van Nubie (die buidige Soedan) gevestig bet, is blykbaar in ca. 543 deur die monofisitiese sendeling, Julianus, tot die Cbristendom bekeer (Adams 1977:443; Hendrich 1984:77), maar die eerste spore van Cbristelike sendingwerk was minstens een eeu vroeer reeds sigbaar (Letsios 1988:210). Sitko, een van die belangrikste stamboofde, wat bomself as "Kleinkoning" betitel bet,. pas in bierdie raamwerk in, maar die datering van sy bewind is kontroversieel: by word tussen die middel van die vyfde en di~ van die sesde eeu geplaas, betsy as beiden, betsy as Christen, sonder dat dit tot nou toe moontlik was om afdoende bewyse vir 'n finale datering te lewer.

Na die dood van Kleopatra in 30 v.C. word Egipte 'n Romeinse provinsie met C. Cornelius Gallus as eerste praefectus. Dieselfde jaar nog moet hierdie goewerneur 'n opstand in Bo-Egipte (die Theba'is) onderdruk, en vroeg in 29 v.C. het hy aandag aan die suidelike grens van Egipte geskenk. In April van daardie jaar het hy dan ook 'n drietalige inskripsie (Grieks, Latyn, hierogliewe)t op 'n stele voor die tempel van Augustus te Philae aangebring. In die teks verwys Gallus na die onderdrukking van die opstand in die Theba'is, na 'n vredesverdrag met die Meroiete ("Ethiopiers" in die teks) en na die vestiging van die Romeinse gesag oor die sogenaamde Triakontaschoenos.

This article examines the question whether the territories, given by the Venetians and the regent of the Latin Empire, Henri of Flanders, to Theodoros Branas after the conquest of Constantinople by the crusaders in 1204, can be defined as a “Territorialstaat”. In fact, these grants must be considered within a feudal framework, while taking into account the particularities of the Latin Empire and its precarious situation. It thus becomes clear that the Latins created a buffer-territory against the Bulgaro-Vlachs and Coumans, which cannot be defined as autonomous or independent. Branas's so-called “state” was short-lived and did not survive its “founder”.

This article examines the image of the Axumite rulers (2nd—6th centuries AD) as reflected in their eight Greek inscriptions. Special attention is paid to the royal titles and the royal deeds as reflected in the inscriptions. This makes us to believe that the kings envisaged a Pax Axumitica, not unlike the Pax Romana or Pax Byzantina The Axumite kings projected an image for the Greek speaking world, which was acceptable to that world in order to be admitted to the civilised oikoumene. Nevertheless, the Axumite kings did not leave out their own Ethiopian background, thus successfully-we believe—trying to balance local interests with international prestige.

When Dhu Nuwas, the Judaised ting of the Homerites (Yemenites), persecuted the Christians, the Axumite king, Caleb, invaded Yemen, defeated Dhu Nuwas, and replaced him with a Christian king. Although the main sources give the name of Abraha, this king must have been—in fact—Esimiphaios, Abraha taking power only as result of a coup against Esimiphaios. The coronation ceremony of the first king of the Homerites seems—at first view—to have followed the contemporary Byzantine model. But, a closer analysis of the sources suggests that the Judaic prototype was followed.

In a Flemish poem of the beginning of the thirteenth century, amongst several well-known heroes, the name of Digene is mentioned. Since Hesseling's article in BZ 22 (1913), it has been generally accepted that this hero should be identified with the Byzantine Digenis Akritas, which postulates a Flemish (or French) translation of the Digenis epic. However, there are two other possible identifications: Theagenes (the hero of Heliodoros' Aithiopica) and Degener (mentioned in a Flemish folk song). This article re-examines the arguments of the different theories and concludes that the identification of Digene with Theagenes is, although not certain, nevertheless the most plausible, thus casting serious doubt on the validity of any conclusions which have derived from the Digenis-option.

The safety and efficacy of the sustained release (SR) mebeverine capsule was compared to the standard plain mebeverine capsule in the treatment of 60 patients suffering from irritable bowel syndrome. Patients, with a score of at least 44 on the Kruis scale, were randomized into a two-period crossover trial. Each treatment period lasted for 6 weeks during which the patients took mebeverine plain 135 mg, two capsules t.i.d., or mebeverine sustained release 200 mg (SR), two capsules b.i.d. After 6 weeks of each treatment, both treatments were regarded 'effective' or 'very effective' by the patient as well as the investigator in more than 80% of the cases. After 3 weeks of the first treatment, the disease score was rated light in 73% of the patients with both medications. After 6 weeks, nine patients (33%) were symptom-free with mebeverine plain, and five (18%) with mebeverine SR. During the second treatment period the number of symptom-free cases reached about 40% with both formulations. Considering the clinical general improvement, more than 70% of all patients had improved after 3 weeks of the first treatment. An additional improvement was reported in 13 patients with mebeverine plain and in 10 patients with mebeverine SR after the next 3 weeks. Abdominal pain was still present in more than 50% of patients but with lower intensity compared with baseline values. Mean scores of efficacy were very similar for both treatments after 3 and 6 weeks (2.0 for mebeverine plain vs. 1.9 for mebeverine SR). The statistical comparison of all scores between the two formulations did not show a significant difference at any time. Very few adverse events were noted and a causal relationship with the study medications was judged as improbable or definitely unrelated. Compliance was close to 100% for most of the patients. The results of the present study indicate that the mebeverine SR capsule provides equivalent efficacy and tolerance to mebeverine plain in the treatment of irritable bowel syndrome (IBS), while reducing the number of daily doses from three to two.

This article examines and explains the meaning and value of two cryptic songs referring to Nikephoros II Phokas' murder by Theophano and John Tsimiskes, i. e. a satirical song, connected with an enacted diapompeusis and an akritiko tragoudi about Tsimiskes. It also explains why both songs, coming from different strata of the Byzantine populations and different regions of the Empire, have been preserved but became cryptic.

This article examines the epigrams of Agathias Scholastikos, referring to ‘icons’, within the context of the religiosity, art techniques and theology of the 6th century. The conclusions are (i) Agathias' poems reflect the general, popular theological knowledge of his time; (ii) the typology and technique of the icons, mentioned in the epigrams, are different for every case and can be identified; (iii) at least one of the icons was a personal dedication by Agathias, but it is difficult to speculate about Agathias'piety.

The Gabriel-Popescu Theorem states essentially that every Grothendieck category is (up to equivalence) of the form ( R ,σ)- mod , i.e., the quotient category of some left module category R - mod , by some Serre subcategory T σ associated to an idempotent kernel functor σ. It follows that every Grothendieck category is a Giraud suncategory of a left module category. In this paper, we study the relationship between derived functors in a Grothendieck category C and a Giraud subcategory D . With C = R - mod , the foregoing thus yields methods to study derived functors in arbitrary Grothendieck categories from knowledge about derived functors in R - mod .

A 44-year-old male patient with an undefined mass in the left ventricular endocardium was scheduled for minimally invasive cardiac surgery. Ventricular investigation and tissue biopsies were completed with the help of a voice-controlled robotic arm. Pathologic examination revealed non-bacterial thrombotic endocarditis. In addition to videoscopy, robotic assistance allows an easier diagnostic and therapeutic approach of intraventricular pathologies.

45 patients in premature labor entered the study, four dropped out for administrative reasons. The remaining 41 patients started all with an intravenous treatment followed by oral treatment with sustained-release ritodrine at a daily dosage of 120 mg per day until the 36th week of gestation. The mean gestational age at entry was 31.26 weeks ± 3.27 and at delivery 37.76 weeks ± 2.11 or a mean gain in days of 44.61 days ± 20.85. A cluster analysis splitting the patients into four groups regarding the gestational age at entry and the Baumgarten tocolytic index showed that even the high-risk patients benefit remarkably by the treatment. The side effect rate was low as well for palpitation as for tremor. The patient compliance was excellent. No neonatal deaths or stillborns occurred during this study.

In an open multicentre study designed to closely reflect the clinical situation, 315 out-patients diagnosed by their psychiatrist as having depression and/or obsessive-compulsive disorder (OCD), and/or panic disorder, were treated for 12 weeks with fluvoxamine (100-300 mg/day). Twelve weeks of fluvoxamine therapy was completed by 229 (73%) patients. Longer illness duration prior to treatment was associated with a significantly reduced rate of treatment withdrawal, whereas a diagnosis of OCD was predictive of treatment withdrawal. The main reasons patients discontinued fluvoxamine therapy were adverse effects experienced before Week 8, and clinical improvement thereafter. Age, sex, and diagnosis bad no predictive value for treatment outcome; however, psychiatric antecedents and duration and severity of illness at baseline were significant predictors of disease severity at endpoint. Fluvoxamine decreased both the frequency and severity of baseline symptoms, with improvement continuing for the duration of the study. Nausea was the only symptom to show an initial increase in frequency and severity, but this subsided after 4 weeks to levels below baseline frequency and severity

The in vitro activity of teicoplanin, a new antibiotic related to vancomycin, was determined against 456 gram-positive cocci. The activity of teicoplanin in comparison with that of vancomycin was similar against staphylococci but 4 to 40 times higher against enterococci and beta-hemolytic and viridans streptococci. The single-dose pharmacokinetics of teicoplanin were studied in six healthy volunteers after administration of 3 and 6 mg/kg intravenously and of 3 mg/kg intramuscularly. The kinetic parameters after both intravenous doses were very similar. The curves for concentration in plasma for the 3- and 6-mg/kg intravenous doses showed a triexponential decline with elimination half-lives of 47.3 and 44.1 h, respectively. The percentages of the doses recovered in urine (0 to 102 h) were 43.2 and 44.1%, respectively. The areas under the plasma curves were dose related: 256.5 and 520.9 micrograms/h per ml, respectively. The bioavailability of teicoplanin after injection of 3 mg/kg intramuscularly was 90%, and the peak level was 7.1 micrograms/ml. The mean levels in plasma 24 h after the 3-mg/kg doses were 2.1 and 2.3 micrograms/ml, respectively, and the mean level in plasma 24 h after the 6-mg/kg intravenous dose was 4.2 micrograms/ml.

An analysis of clinical, haematological, histological and cytogenetic data was performed in 85 consecutive patients with myelodysplastic syndromes (MDS). The criteria for diagnosis of refractory anaemia (RA), acquired idiopathic sideroblastic anaemia (AISA) and chronic myelomonocytic leukaemia (CMML) were clearly defined, since the inclusion criteria provided by the FAB co-operative group are imprecise. None of these patients has received chemotherapy during the follow-up period. The median survival of the whole group was only 15 months, with less than 10% of the patients surviving after 5 years. Fifteen patients (17.6%) were still alive at time of analysis, 31 (36.5%) have developed acute myeloid leukaemia (AML) and only one of them is still alive; 30 (35.3%) died of infectious and/or haemorrhagic complications. Patients who developed AML had a shorter survival (median survival time 9.5 versus 15 months) but this difference was not significant (P = 0.10). Factors with prognostic value are in order of significance: abnormal localized immature myeloid precursors (= ALIP) in the trephine biopsy, circulating myeloblasts, excess of blasts in the bone marrow smears, age, FAB classification and granulocyte count. In comparison to refractory anaemia with excess of blasts (RAEB), CMML and RAEB in transformation (RAEBt), patients with RA and AISA had a lower incidence of evolution to AML (11% versus 56%), but a higher mortality rate from infections and/or bleeding (59.2% versus 29%). ALIP negative cases were only found among patients with RA and AISA, whereas ALIP positivity was observed in all cases of RAEB and RAEBt, in 10/11 patients with CMML and in almost half the cases of RA and AISA. In RA and AISA patients survival was significantly different between ALIP positive and ALIP negative cases (P = 0.009). Among MDS patients, ALIP negative cases developed significantly less AML than ALIP positive cases (5% versus 44%), but a similar percentage of mortality from infectious and/or haemorrhagic complications was seen in both groups (33% versus 36.5%). Chromosomal analysis proved to be of no significant prognostic value, although a trend for shorter survival was observed in patients with complex karyotype anomalies or without mitoses. Because of their prolonged survival, antileukaemic chemotherapy is contra-indicated in ALIP negative patients (median survival 50 months). Nevertheless they only constitute a minor subgroup of MDS cases. Prognosis in ALIP positive patients is poor (median survival 12.5 months); in these patients therapeutic trials with cytostatic drugs or with inducers of differentiation of myeloid precursor cells seem to be justified.

Forty bone-marrow trephine biopsies of patients with myelodysplastic syndromes (MDS) were studied and compared with bone marrow smears. It proved possible to make the diagnosis of MDS on the basis of bone-marrow biopsies. Features of abnormal erythropoiesis and myelopoiesis, although different from those observed in smears, were easily detectable. Moreover, obvious advantages of bone-marrow biopsy over bone-marrow smears were found. Firstly, the biopsy in MDS gives an exact assessment of the cellularity; secondly, the presence of reticulin fibres, increased in the majority of the cases, can be evaluated; thirdly, dysmegakaryopoiesis is more easily detected in trephine biopsies than in smears; finally, abnormal behaviour of myeloblasts, clustering centrally in the bone marrow, is frequently observed before the smears show an excess of myeloblasts. The bone-marrow biopsy also has a role in difficult cases, where the diagnosis of MDS can not be established on just bone-marrow smears. The five types of MDS, as described by the FAB group, do not represent recognizable histological entities.

Menopausal women receiving 0.625 mg/day conjugated oestrogen continuously for 6 mth were also given either 10 mg/day dydrogesterone continuously or 20 mg/day for the first 12 days of each calendar month in order to evaluate both the efficacy and the tolerance of each regimen. The following parameters were assessed: subjective symptoms, bleeding patterns, lipid metabolism, glycaemia, weight and blood pressure. Of the 81 patients who entered the study, 60 opted for the continuous treatment and 21 for the cyclic treatment. Seven (7) patients dropped out, 6 for administrative reasons and 1 because of nausea. The two groups were comparable with regard to all parameters, with the exception of the duration of pretreatment amenorrhoea, which was longer in the continuous-treatment group (40.6 vs. 19.1 mth), and the initial lipid profile levels, which were higher in the same group. The subjective symptoms were influenced rapidly and positively by both treatments. The other parameters remained unchanged, except for a clinically insignificant rise in triglycerides in both groups. Both treatments were quite satisfactorily accepted by the patients, in spite of a 70% rate of withdrawal bleeding in the cyclic group and a 40% rate of spotting in the continuous-treatment group. Sixty-two (62) patients remained free of side effects, while mastodynia was reported in 9 cases.

2-Nitro-oxaphenalenes are synthetic chemicals which were synthesized in the authors' laboratory. They are the most efficient mutagenic compounds on mammalian cells in culture. They are chemically related to the nitro-naphthofuran family by the displacement of the heterocycle on the naphthalene ring. Since nitro-naphthofurans have a strong mutagenic activity in bacterial tests without metabolic activation and are active in-vivo carcinogens, the purpose of this study was to demonstrate the carcinogenic activity of two 2-nitro-oxaphenalenes. The two compounds were injected s.c. into Wistar rats initially 6-weeks-old. They were dissolved in dimethylsulfoxide (DMSO) at a concentration of 1 mg/ml. A s.c. injection of 0.5 ml containing 0.5 mg of carcinogen was given once a week in the neck of each animal tested. Five control animals were not injected and five animals received 0.5-ml injection of DMSO every week to serve as a control. The animals developed tumors only at the site of injection. The tumors were classified as high grade fibrosarcomas. This experiment demonstrates that: (i) 2-nitro-oxaphenalenes are very active in-vivo carcinogens in rats; (ii) there is a good correlation between the high mutagenic activity especially in mammalian tests and the strong carcinogenicity of the compounds; and (iii) the presence of a 6-methoxy group increases by two-fold the carcinogenic potential.

Evaluation of the genotoxicity of epoxides is best carried out on a case by case basis. Although glycidyltrimethylammonium chloride (GTAC) is widely used in several industrial applications, its genotoxicity is poorly documented. Therefore, we have evaluated GTAC in a battery of 4 in vitro short-term tests for genotoxicity. We report here that GTAC mediates the induction of base-pair substitutions in S. typhimurium, gene conversion in S. cerevisiae (D7), chromosomal aberrations in CHO cells and viral DNA amplification in Chinese hamster CO6O cells. In view of these results, it is advisable to consider GTAC a potential carcinogen.

SummaryOut of ten patients with brain abscess, observed over a period of fifteen months, eight were associa ted with Streptococcus milleri, either in pure culture or as part of a mixed flora with strict anaerobes. Inspite of surgery and chemotherapy, two patients died and one survived with severe sequelae.The taxonomic position, the ecology, the pathogenic spectrum, and the bacteriologic diagnosis of S. milleri are reviewed.

Mut. Res. ISI Document Delivery No.: JC401 Times Cited: 4 Castelain, P; Hendrickx, B; Tromelin, A; Demerseman, P; Moens, W Elsevier science bv Amsterdam Cited Reference Count: 26; International audience; The mutagenic activity of five dichloroethylamino 2-nitrobenzofuran derivatives and one dichloroethylamino 2-nitronaphthofuran derivative was analysed in the Salmonella/microsome assay. We investigated the influence of the position of the dichloroethylamino and/or the methoxy groups on the mutagenic activity of these nitro arenofurans in S. typhimurium strain TA100 and its variant TA100NR, deficient in nitroreductase. Without metabolic activation 7-[bis(2-chloroethyl)amino]-2-nitronaphtho[2,1-b]furan (1), 4-[bis(2-chloroethyl) amino]-7-methoxy-2-nitrobenzofuran (2), 7-[bis(2-chloroethyl)amino]-4-methoxy-2-nitrobenzofuran (5) and 6-[bis(2-chloroethyl)amino]-2-nitrobenzofuran (6) are mutagenic in TA100, while 4-[bis(2-chloroethyl)amino]-5-methoxy-2-nitrobenzofuran (4) is weakly mutagenic and 5-[bis(2-chloroethyl)amino]-2-nitrobenzofuran (3) toxic. In the NR deficient strain compounds 1, 3 and 6 are strong mutagens and 4 is weakly positive. The two isomers 2 and 5 are negative in that strain. The naphthofuran derivative 1 is highly mutagenic in the absence of S9 mix in both strains considered, but less than R7000 (7). A decrease in the electronic polarity of compound 1 versus compound 7 according to the hypothesis developed by Royer et al. is a possible explanation. After exogenous metabolic activation by S9 mix all the compounds tested are highly mutagenic in both Salmonella strains. The position of the dichloroethylamino group and/or the presence of a methoxyl on the alpha-nitroarenofuran derivatives seem to modify the activity of bacterial as well as exogenous nitroreductases or other activating enzymes.