Effect of intradialytic resistance band exercise on physical function in patients on maintenance hemodialysis: a pilot study.

Although physical activity is recommended in patients on maintenance hemodialysis (MHD), randomized controlled trials testing the effects of exercise in this population have given conflicting results. In general, aerobic exercises mostly failed to produce improvements in physical function, whereas resistance exercises, although less studied, appeared to be more promising. The use of sophisticated materials such as leg press and free weights may preclude widespread application of resistance training in patients on MHD. Simple and cheap elastic bands may thus be an attractive alternative. We tested the feasibility of a supervised intradialytic resistance band exercise training program, and its effects on physical function, in patients on MHD. A total of 11 unselected adult patients on MHD from our center, aged 70 ± 10.7 (mean ± standard deviation) years, including 8 men and 3 women, accepted to follow the program under the supervision of qualified physiotherapists. Thirty-six exercise sessions of moderate intensity (twice a week, mean duration 40 minutes each, during 4.5 to 6 months), mainly involving leg muscles against an elastic resistance, were performed. The exercise program was well tolerated and all patients completed it. Statistically significant improvements were observed in the following tests: Tinetti test, 23.9 ± 3.9 points before versus 25.7 ± 3.5 points after the program (P = .022); the Timed Up and Go test, 12.1 ± 6.6 versus 10 ± 5.8 seconds (P = .0156). Improvements in the 6-minute walk distance and in the one-leg balance tests just failed to reach statistical significance. In this single-center pilot study, an intradialytic resistance band exercise program was feasible, well tolerated, and showed encouraging results on physical function.

Prediction of plant species distributions across six millennia.

The usefulness of species distribution models (SDMs) in predicting impacts of climate change on biodiversity is difficult to assess because changes in species ranges may take decades or centuries to occur. One alternative way to evaluate the predictive ability of SDMs across time is to compare their predictions with data on past species distributions. We use data on plant distributions, fossil pollen and current and mid-Holocene climate to test the ability of SDMs to predict past climate-change impacts. We find that species showing little change in the estimated position of their realized niche, with resulting good model performance, tend to be dominant competitors for light. Different mechanisms appear to be responsible for among-species differences in model performance. Confidence in predictions of the impacts of climate change could be improved by selecting species with characteristics that suggest little change is expected in the relationships between species occurrence and climate patterns.

Rifaximin treatment for the irritable bowel syndrome with a positive lactulose hydrogen breath test improves symptoms for at least 3 months.

BACKGROUND: While rifaximin was able to improve symptoms in patients with irritable bowel syndrome (IBS) in phase III trials, these results are yet to be repeated in phase IV studies. AIM: To evaluate the treatment response to rifaximin in IBS patients in a phase IV trial. METHODS: IBS patients underwent lactulose hydrogen breath testing (LHBT). LHBT-positive patients were treated with rifaximin for 14 days. Prior to treatment as well as at week 4 and 14 following the start of rifaximin treatment, patients completed a questionnaire assessing symptom severity on a Likert scale from 0 to 10. RESULTS: One hundred and six of 150 IBS patients (71%) were LHBT-positive and treated with rifaximin. As assessed at week 4 following commencement of the therapy, rifaximin provided significant improvement of the following IBS-associated symptoms: bloating (5.5±2.6 before the start of the treatment vs. 3.6±2.7 at week 4, P<0.001), flatulence (5.0±2.7 vs. 4.0±2.7, P=0.015), diarrhoea (2.9±2.4 vs. 2.0±2.4, P=0.005) and abdominal pain (4.8±2.7 vs. 3.3±2.5, P<0.001). Overall well-being also significantly improved (3.9 ± 2.4 vs. 2.7 ± 2.3, P < 0.001). Similar improvements in IBS symptoms were obtained at week 14. Eighty-six per cent of patients undergoing repetitive LHBT (55/64) tested negative at week 4. CONCLUSIONS: We found a high percentage of LHBT-positive IBS patients. IBS-associated symptoms (bloating, flatulence, diarrhoea, pain) were improved for a period of 3 months following 2 weeks of treatment with rifaximin. We conclude that rifaximin treatment alleviates symptoms in LHBT-positive IBS patients.

Cardiorespiratory and Cardiac Autonomic Responses to 30-15 Intermittent Fitness Test in Team Sport Players

Buchheit, M, Al Haddad, H, Millet GP, Lepretre, PM, Newton, M, and Ahmaidi, S. Cardiorespiratory and cardiac autonomic responses to 30-15 Intermittent Fitness Test in team sport players. J Strength Cond Res 23(1): xxx-xxx, 2009-The 30-15 Intermittent Fitness Test (30-15IFT) is an attractive alternative to classic continuous incremental field tests for defining a reference velocity for interval training prescription in team sport athletes. The aim of the present study was to compare cardiorespiratory and autonomic responses to 30-15IFT with those observed during a standard continuous test (CT). In 20 team sport players (20.9 +/- 2.2 years), cardiopulmonary parameters were measured during exercise and for 10 minutes after both tests. Final running velocity, peak lactate ([La]peak), and rating of perceived exertion (RPE) were also measured. Parasympathetic function was assessed during the postexercise recovery phase via heart rate (HR) recovery time constant (HRRtau) and HR variability (HRV) vagal-related indices. At exhaustion, no difference was observed in peak oxygen uptake (&OV0312;o2peak), respiratory exchange ratio, HR, or RPE between 30-15IFT and CT. In contrast, 30-15IFT led to significantly higher minute ventilation, [La]peak, and final velocity than CT (p < 0.05 for all parameters). All maximal cardiorespiratory variables observed during both tests were moderately to well correlated (e.g., r = 0.76, p = 0.001 for &OV0312;o2peak). Regarding ventilatory thresholds (VThs), all cardiorespiratory measurements were similar and well correlated between the 2 tests. Parasympathetic function was lower after 30-15IFT than after CT, as indicated by significantly longer HHRtau (81.9 +/- 18.2 vs. 60.5 +/- 19.5 for 30-15IFT and CT, respectively, p < 0.001) and lower HRV vagal-related indices (i.e., the root mean square of successive R-R intervals differences [rMSSD]: 4.1 +/- 2.4 and 7.0 +/- 4.9 milliseconds, p < 0.05). In conclusion, the 30-15IFT is accurate for assessing VThs and &OV0312;o2peak, but it alters postexercise parasympathetic function more than a continuous incremental protocol.

Numerical and ExperimentalModelling of Gas Flow and Heat Transfer in the Air Gap of An Electric Machine

This work deals with the cooling of high-speed electric machines, such as motors and generators, through an air gap. It consists of numerical and experimental modelling of gas flow and heat transfer in an annular channel. Velocity and temperature profiles are modelled in the air gap of a high-speed testmachine. Local and mean heat transfer coefficients and total friction coefficients are attained for a smooth rotor-stator combination at a large velocity range. The aim is to solve the heat transfer numerically and experimentally. The FINFLO software, developed at Helsinki University of Technology, has been used in the flow solution, and the commercial IGG and Field view programs for the grid generation and post processing. The annular channel is discretized as a sector mesh. Calculation is performed with constant mass flow rate on six rotational speeds. The effect of turbulence is calculated using three turbulence models. The friction coefficient and velocity factor are attained via total friction power. The first part of experimental section consists of finding the proper sensors and calibrating them in a straight pipe. After preliminary tests, a RdF-sensor is glued on the walls of stator and rotor surfaces. Telemetry is needed to be able to measure the heat transfer coefficients at the rotor. The mean heat transfer coefficients are measured in a test machine on four cooling air mass flow rates at a wide Couette Reynolds number range. The calculated values concerning the friction and heat transfer coefficients are compared with measured and semi-empirical data. Heat is transferred from the hotter stator and rotor surfaces to the coolerair flow in the air gap, not from the rotor to the stator via the air gap, althought the stator temperature is lower than the rotor temperature. The calculatedfriction coefficients fits well with the semi-empirical equations and precedingmeasurements. On constant mass flow rate the rotor heat transfer coefficient attains a saturation point at a higher rotational speed, while the heat transfer coefficient of the stator grows uniformly. The magnitudes of the heat transfer coefficients are almost constant with different turbulence models. The calibrationof sensors in a straight pipe is only an advisory step in the selection process. Telemetry is tested in the pipe conditions and compared to the same measurements with a plain sensor. The magnitudes of the measured data and the data from the semi-empirical equation are higher for the heat transfer coefficients than thenumerical data considered on the velocity range. Friction and heat transfer coefficients are presented in a large velocity range in the report. The goals are reached acceptably using numerical and experimental research. The next challenge is to achieve results for grooved stator-rotor combinations. The work contains also results for an air gap with a grooved stator with 36 slots. The velocity field by the numerical method does not match in every respect the estimated flow mode. The absence of secondary Taylor vortices is evident when using time averagednumerical simulation.

Six Sigman soveltamisedellytysten ja -apuvälineiden luominen

Diplomityön tavoitteena oli luoda soveltamisedellytyksiä ja -apuvälineitä Six Sigma -parannusprojektien läpiviennille Perlos Oyj Connectorsin meistoprosessissa. Työn teoriaosassa käsitellään Six Sigman perusteoriaa, organisointia ja soveltamista sekä suorituskykymittariston ja tiedonkeruumenetelmien luomista. Kirjallisuuden tarjoaman teorian jälkeen työssä tutustuttiin meistoprosessiin ja Perloksen tapaan soveltaa Six Sigmaa prosessien parantamiseen. Tämän perusteella kehitettiin tiedonkeruu-, dokumentointi- ynnä muita apuvälineitä parantamisprojektien tueksi. Lopuksi koekäytettiin luotuja välineitä meistoon tehdyn osittaisen Six Sigma -projektin yhteydessä. Luotettavan tiedon saaminen prosesseista on perusedellytys Six Sigma -projektien läpiviennille. Menetelmän kouluttaminen työntekijöille on myös tärkeää. Erilaiset dokumentointi- ja laskentakaavakkeet toimivat projektien läpiviennin ja seurannan tukena. Työssä luotuja tiedonkeruu-, koulutus-, dokumentointi- ynnä muita apuvälineitä voidaan käyttää jatkossa apuna Perloksella tehtävissä Six Sigma -projekteissa. Mittaristoa ja tiedonkeruuta tulee kehittää edelleen, jotta prosessien toimintaa voidaan analysoida tehokkaasti. Työn lopussa on ajatuksia Six Sigman käytöstä sekä tiedonkeruujärjestelmien jatkokehityksestä.

Application of intravoxel incoherent motion perfusion imaging to shoulder muscles after a lift-off test of varying duration.

Intravoxel incoherent motion (IVIM) MRI is a method to extract microvascular blood flow information out of diffusion-weighted images acquired at multiple b-values. We hypothesized that IVIM can identify the muscles selectively involved in a specific task, by measuring changes in activity-induced local muscular perfusion after exercise. We tested this hypothesis using a widely used clinical maneuver, the lift-off test, which is known to assess specifically the subscapularis muscle functional integrity. Twelve shoulders from six healthy male volunteers were imaged at 3 T, at rest, as well as after a lift-off test hold against resistance for 30 s, 1 and 2 min respectively, in three independent sessions. IVIM parameters, consisting of perfusion fraction (f), diffusion coefficient (D), pseudo-diffusion coefficient D* and blood flow-related fD*, were estimated within outlined muscles of the rotator cuff and the deltoid bundles. The mean values at rest and after the lift-off tests were compared in each muscle using a one-way ANOVA. A statistically significant increase in fD* was measured in the subscapularis, after a lift-off test of any duration, as well as in D. A fD* increase was the most marked (30 s, +103%; 1 min, +130%; 2 min, +156%) and was gradual with the duration of the test (in 10(-3) mm(2) /s: rest, 1.41 ± 0.50; 30 s, 2.86 ± 1.17; 1 min, 3.23 ± 1.22; 2 min, 3.60 ± 1.21). A significant increase in fD* and D was also visible in the posterior bundle of the deltoid. No significant change was consistently visible in the other investigated muscles of the rotator cuff and the other bundles of the deltoid. In conclusion, IVIM fD* allows the demonstration of a task-related microvascular perfusion increase after a specific task and suggests a direct relationship between microvascular perfusion and the duration of the effort. It is a promising method to investigate non-invasively skeletal muscle physiology and clinical perfusion-related muscular disorders.

On the Use of a Test to Exhaustion Specific to Tennis (TEST) with Ball Hitting by Elite Players

PURPOSE: We aimed to a) introduce a new Test to Exhaustion Specific to Tennis (TEST) and compare performance (test duration) and physiological responses to those obtained during the 20-m multistage shuttle test (MSST), and b) determine to which extent those variables correlate with performance level (tennis competitive ranking) for both test procedures. METHODS: Twenty-seven junior players (8 males, 19 females) members of the national teams of the French Tennis Federation completed MSST and TEST, including elements of the game (ball hitting, intermittent activity, lateral displacement), in a randomized order. Cardiorespiratory responses were compared at submaximal (respiratory compensation point) and maximal loads between the two tests. RESULTS: At the respiratory compensation point oxygen uptake (50.1 +/- 4.7 vs. 47.5 +/- 4.3 mL.min-1.kg-1, p = 0.02), but not minute ventilation and heart rate, was higher for TEST compared to MSST. However, load increment and physiological responses at exhaustion did not differ between the two tests. Players' ranking correlated negatively with oxygen uptake measured at submaximal and maximal loads for both TEST (r = -0.41; p = 0.01 and -0.55; p = 0.004) and MSST (r = -0.38; P = 0.05 and -0.51; p = 0.1). CONCLUSION: Using TEST provides a tennis-specific assessment of aerobic fitness and may be used to prescribe aerobic exercise in a context more appropriate to the game than MSST. Results also indicate that VO2 values both at submaximal and maximal load reached during TEST and MSST are moderate predictors of players competitive ranking.

Dissolution test for glibenclamide tablets

The aim of this work is to develop and validate a dissolution test for glibenclamide tablets. Optimal conditions to carry out the dissolution test are 500 mL of phosphate buffer at pH 8.0, paddles at 75 rpm stirring speed, time test set to 60 min and using equipment with six vessels. The derivative UV spectrophotometric method for determination of glibenclamide released was developed, validated and compared with the HPLC method. The UVDS method presents linearity (r² = 0.9999) in the concentration range of 5-14 µg/mL. Precision and recoveries were 0.42% and 100.25%, respectively. The method was applied to three products commercially available on the Brazilian market.

Computational methods for tactical simulations

Tämä taktiikan tutkimus keskittyy tietokoneavusteisen simuloinnin laskennallisiin menetelmiin, joita voidaan käyttää taktisen tason sotapeleissä. Työn tärkeimmät tuotokset ovat laskennalliset mallit todennäköisyyspohjaisen analyysin mahdollistaviin taktisen tason taistelusimulaattoreihin, joita voidaan käyttää vertailevaan analyysiin joukkue-prikaatitason tarkastelutilanteissa. Laskentamallit keskittyvät vaikuttamiseen. Mallit liittyvät vahingoittavan osuman todennäköisyyteen, jonka perusteella vaikutus joukossa on mallinnettu tilakoneina ja Markovin ketjuina. Edelleen näiden tulokset siirretään tapahtumapuuanalyysiin operaation onnistumisen todennäköisyyden osalta. Pienimmän laskentayksikön mallinnustaso on joukkue- tai ryhmätasolla, jotta laskenta-aika prikaatitason sotapelitarkasteluissa pysyisi riittävän lyhyenä samalla, kun tulokset ovat riittävän tarkkoja suomalaiseen maastoon. Joukkueiden mies- ja asejärjestelmävahvuudet ovat jakaumamuodossa, eivätkä yksittäisiä lukuja. Simuloinnin integroinnissa voidaan käyttää asejärjestelmäkohtaisia predictor corrector –parametreja, mikä mahdollistaa aika-askelta lyhytaikaisempien taistelukentän ilmiöiden mallintamisen. Asemallien pohjana ovat aiemmat tutkimukset ja kenttäkokeet, joista osa kuuluu tähän väitöstutkimukseen. Laskentamallien ohjelmoitavuus ja käytettävyys osana simulointityökalua on osoitettu tekijän johtaman tutkijaryhmän ohjelmoiman ”Sandis”- taistelusimulointiohjelmiston avulla, jota on kehitetty ja käytetty Puolustusvoimien Teknillisessä Tutkimuslaitoksessa. Sandikseen on ohjelmoitu karttakäyttöliittymä ja taistelun kulkua simuloivia laskennallisia malleja. Käyttäjä tai käyttäjäryhmä tekee taktiset päätökset ja syöttää nämä karttakäyttöliittymän avulla simulointiin, jonka tuloksena saadaan kunkin joukkuetason peliyksikön tappioiden jakauma, keskimääräisten tappioiden osalta kunkin asejärjestelmän aiheuttamat tappiot kuhunkin maaliin, ammuskulutus ja radioyhteydet ja niiden tila sekä haavoittuneiden evakuointi-tilanne joukkuetasolta evakuointisairaalaan asti. Tutkimuksen keskeisiä tuloksia (kontribuutio) ovat 1) uusi prikaatitason sotapelitilanteiden laskentamalli, jonka pienin yksikkö on joukkue tai ryhmä; 2) joukon murtumispisteen määritys tappioiden ja haavoittuneiden evakuointiin sitoutuvien taistelijoiden avulla; 3) todennäköisyyspohjaisen riskianalyysin käyttömahdollisuus vertailevassa tutkimuksessa sekä 4) kokeellisesti testatut tulen vaikutusmallit ja 5) toimivat integrointiratkaisut. Työ rajataan maavoimien taistelun joukkuetason todennäköisyysjakaumat luovaan laskentamalliin, kenttälääkinnän malliin ja epäsuoran tulen malliin integrointimenetelmineen sekä niiden antamien tulosten sovellettavuuteen. Ilmasta ja mereltä maahan -asevaikutusta voidaan tarkastella, mutta ei ilma- ja meritaistelua. Menetelmiä soveltavan Sandis -ohjelmiston malleja, käyttötapaa ja ohjelmistotekniikkaa kehitetään edelleen. Merkittäviä jatkotutkimuskohteita mallinnukseen osalta ovat muun muassa kaupunkitaistelu, vaunujen kaksintaistelu ja maaston vaikutus tykistön tuleen sekä materiaalikulutuksen arviointi.

A conglutination test for rapid detection of antibodies against Babesia bigemina

A rapid conglutination test (RCT) with performance comparable to the indirect fluorescent antibody technique (IFAT) was developed to detect antibodies against Babesia bigemina (B. bigemina-RCT). The B. bigemina-RCT is a sensitive, specific, economical, and rapidly performed serological test suitable for field application or minimally equipped laboratories. This test had a sensitivity of 90.9%, and specificity of 97.6%, compared to IFAT, which showed for the same parameters respectively, 98.3% and 99.7%. The early detection of anti- B. bigemina immunoglobulins by RCT in experimental infections was nearly parallel to that of IFAT. Cross reactions were observed with sera from calves experimentally infected with Babesia bovis (1.8%) and with Anaplasma marginale (1.2%). RCT antigen prepared with non parasitized erythrocytes (negative antigen) showed 1.5%, 3.5% and 2.2% of positive reactions with sera from animals experimentally infected with B. bigemina, B. bovis and A. marginale. However, none of the sera from animals of endemic areas for babesia infection resulted in positive reactions with the negative antigen. Considering these results and shelf life over six months, the B. bigemina-RCT could be used for epidemiological surveys and evaluation of control measures against this species of Babesia.

Vertaileva tapaustutkimus kuusivuotiaiden opetus–oppimis -vuorovaikutuksesta, matematiikkaepisodeista ja lukukäsitteen osaamisesta

Tässä vertailevassa kansainvälisessä tapaustutkimuksessa tarkasteltiin kuusivuotiaiden matematiikan tuntien opetus–oppimis -vuorovaikutusta ja lukukäsitteen osaamista Suomen, Englannin ja Ruotsin toiminta- ja oppimisympäristöissä. Toteutuneita opetus–oppimis -prosesseja verrattiin opetussuunnitelmien yleisiin- ja matematiikan tavoitteisiin sekä lukukäsitteen osaamistasoon. Empiirinen tutkimusaineisto sisälsi lasten (N=99) lukukäsitteen osaamistason yksilötestauksen ja laadullisen analyysin yhteensä seitsemän viikon matematiikan tuntien (880 minuutin) videoidusta opetus – oppimis -vuorovaikutuksesta. Minuutin analyysiyksikköina tarkasteltuna kuusivuotiaiden tutkimusviikon matematiikan tuntien opetus–oppimis -vuorovaikutuksesta lähes puolet ilmensi opettajalähtöisyyttä, kolmannes oppijalähtöisyyttä ja lähes viidennes ilmensi jaettua vuorovaikutusta. Kun tutkimusviikon matematiikan opetusta tarkasteltiin merkityksellisten vuorovaikutuskokonaisuuksien, episodien luokittelun pohjalta havaittiin, että kaikista viikon matematiikkaepisodeista (N=371) yli puolet edusti opettajalähtöisyyttä ja kolmannes edusti opettajalähtöisen ja jaetun vuorovaikutuksen yhdistelmää. Episodien keskimääräinen kesto oli noin kaksi minuuttia tässä tutkimuksessa. Tuloksissa ilmeni ryhmien välisiä eroja opetus–oppimis -vuorovaikutuksen ominaisuuksissa sekä erityyppisiä matematiikan tuntien rakennemalleja ja lukukäsitteen osaamistasoeroja. Monipuolinen ja muita näytteitä enemmän jaettua vuorovaikutusta edustava oppimisympäristö, oli tässä aineistossa yhteydessä keskiarvoa korkeampaan lukukäsitteen osaamistasoon. Korostetun opettajalähtöinen oppimisympäristö oli yhteydessä keskimääräiseen lukukäsitteen osaamistasoon. Muita tutkimuskohteita oppijalähtöisempi oppimisympäristö oli yhteydessä keskimääräisistä alempaan lukukäsitteen osaamistasoon. Tutkimustulosten perusteella tarkentuu kuva erilaisista opetus–oppimis -prosessin osatekijöistä, joita voidaan mahdollisesti soveltaa eri oppiaineisiin vastaavanlaisissa formaaleissa oppimisympäristöissä.

Evaluation of tear production with modified Schirmer tear test-1 during the neonatal period in cats

The study aimed to evaluate tear production by means of modified Schirmer tear tes-1 (mSTT-1) in neonate cats. Likewise, correlation between mSTT-1 and STT-1 was assessed in vitro. Standard SST strips were cut in half and after eye lid opening, tear production of neonates (n=15) was daily measured in both eyes (mSTT-1), until the 7th day, and at day 14, 21, and 28. Animals were daily weighted until 28 days of age. Results were compared statistically (P<0.05). During the first 7 days, the overall mSTT-1 mean was 0.76 wetting/minute. Significant differences between right and left eyes were not observed at any time point (P=1.00). Tear secretion increased significantly, from the 14th to 28th day, in comparison with 7 first days (P<0.05). Positive correlation between maturity parameters and tear secretion was observed (P<0.0001). Distance between slopes of each strip changed significantly (P<0.0001). It was concluded that tear secretion in the neonatal period of cats is very below the reference values described for young and adults of the same species. It is not possible to extrapolate results obtained with mSTT-1 to standard STT-1.

Transfer of passive immunity and serum proteinogram in the first six months of life of Criollo Lageano and black and white holstein calves

The objective of this study was to evaluate and compare the transfer of passive immunity and the proteinogram in Criollo Lageano (CL) and Black and White Holstein (BWH) calves. Two groups were utilized with 13 Criollo Lageano and 10 BWH calves. Blood samples were collected for the measurement of total serum protein, electrophoresis of serum proteins, activity of the gamma glutamyl transferase, and concentration of IgG by the method of the zinc sulfate turbidity in periods between 24 and 36 hours of life, 15, 30, 60, 90, 120, 150 and 180 days. Statistical analysis was performed by ANOVA and Tukey test at 5% significance level, and correlations between variables were calculated. Variations of serum proteins followed a pattern of physiological behavior over the first six months of life and production of immunoglobulins was active earlier in BWH calves and slower in the Criollo Lageano, without causing any impact on their health. Gamma globulin in the first days of life (24-36h) was correlated with IgG (r=0.87 for CL and r=0.89 for BWH), PTS (r=0.91 for CL and r=0.92 for BWH), Glob (r=0.99 for CL and r=0.98 for BWH) and GGT (r=0.14 for CL and r=0.83 for BWH). It was concluded that there was no failure in the transfer of passive immunity in Criollo Lageano calves but this failure occurred in the BWH calves. IgG values estimated by the zinc sulfate turbidity and serum proteins were considered good indicators of the transfer of passive immunity in calves between 24 and 36 hours of life.

Genotoxic activity of the insecticide Nuvacron (Monocrotophos) detected by the micronucleus test in bone marrow erythrocytes of mice and in CHO cells

The organophosphorus insecticide Nuvacron (Monocrotophos) is a very toxic agent widely utilized in Brazilian agriculture. To evaluate the clastogenic potential of this insecticide, in vivo and in vitro micronucleus (MN) assay experiments were carried out on Swiss mice and on Chinese hamster ovary (CHO) cells, respectively. Nuvacron administered at doses of 2.5 and 5.0 mg/kg induced a statistically significant increase in the frequencies of MN detected in polychromatic bone marrow erythrocytes from animals (six/group) treated ip 24 h before. Exponentially growing CHAO cells were treated continuously (16h) with Nuvacron diluted in water to final concentrations of 1, 10, 100, 200, and 400 mug/ml. Three experiments were carried out using the cytokinesis-block method and a total of 6000 binucleated cells were scored to determine MN frequencies. A statistically significant increase in the frequencies of MN was observed for the cells treated with 1 and 10 mug/ ml Nuvacron. A marked decrease in cell proliferation rates was observed for CHO cultures treated with higher concentrations. These data demonstrate that Nuvacron has a genotoxic effect on both in vivo and in vitro mammalian test systems.