Genotoxic Effects Induced by Cd(+2), Cr(+6), Cu(+2) in the Gill and Liver of Odontesthes bonariensis (Piscies, Atherinopsidae).

Genotoxic effects of Cd(+2), Cr(+6), and Cu(+2) on the gill and liver of the Argentinean Silverside (Odontesthes bonariensis) were studied using the comet assay and in relation with the metal tissue accumulation. Fish were exposed to three waterborne concentrations of each metal for 2 and 16 days. Genotoxicity was assessed by the single cell gel electrophoresis (comet assay). After 2 days, significant increase of the genetic damage index (GDI) was only observed in the gill of fish exposed to Cr(+6) and Cu(+2), and the LOECs were 2160 nM and 921.1 nM, respectively. The gill LOEC for Cd(+2) by 16 days was 9.4 nM. In the liver, LOECs were obtained only for Cd(+2) and Cr(+6) and were 9.4 and 2160 nM, respectively. The three metals were able to induce genotoxic effects at environmentally relevant concentrations and the gill was the most sensitive organ.

Foot posture is associated with morphometry of the peroneus longus muscle, tibialis anterior tendon, and Achilles tendon.

The aim of this study was to investigate the association between foot type and the morphometry of selected muscles and tendons of the lower limb. Sixty-one healthy participants (31 male, 30 female; aged 27.1 ± 8.8 years) underwent gray-scale musculoskeletal ultrasound examination to determine the anterior-posterior (AP) thickness of tibialis anterior, tibialis posterior, and peroneus longus muscles and tendons as well as the Achilles tendon. Foot type was classified based on arch height and footprint measurements. Potentially confounding variables (height, weight, hip and waist circumference, rearfoot and ankle joint range of motion, and levels of physical activity) were also measured. Multiple linear regression models were used to determine the association between foot type with muscle and tendon morphometry accounting for potentially confounding variables. Foot type was significantly and independently associated with AP thickness of the tibialis anterior tendon, peroneus longus muscle, and Achilles tendon, accounting for approximately 7% to 16% of the variation. Flat-arched feet were associated with a thicker tibialis anterior tendon, a thicker peroneus longus muscle, and a thinner Achilles tendon. Foot type is associated with morphometry of tendons that control sagittal plane motion of the rearfoot; and the peroneus longus muscle that controls frontal plane motion of the rearfoot. These findings may be related to differences in tendon loading during gait.

Energy localization in the phi4 oscillator chain.

We study energy localization in a finite one-dimensional phi(4) oscillator chain with initial energy in a single oscillator of the chain. We numerically calculate the effective number of degrees of freedom sharing the energy on the lattice as a function of time. We find that for energies smaller than a critical value, energy equipartition among the oscillators is reached in a relatively short time. On the other hand, above the critical energy, a decreasing number of particles sharing the energy is observed. We give an estimate of the effective number of degrees of freedom as a function of the energy. Our results suggest that localization is due to the appearance, above threshold, of a breather-like structure. Analytic arguments are given, based on the averaging theory and the analysis of a discrete nonlinear Schrödinger equation approximating the dynamics, to support and explain the numerical results.

Folic acid enhances the apoptotic and genotoxic activity of carboplatin in HeLa cell line.

In human tumor cells, experimental and clinical evidence indicates that some factors involved in signal transduction and cell growth can also modulate the response to chemotherapeutic treatment. The aim of the present study was to investigate the role of folic acid (FA) as a modulator of carboplatin (CBDCA) activity. Genotoxicity and cytotoxicity induced by CBDCA alone and in combination with FA were assessed in cultured HeLa cells. We used comet assay, mitotic index analysis, MTT and NR assays, cytokinesis-block micronucleus cytome assay and annexin V-IP as different cytotoxicity and genotoxicity approaches for human cervical carcinoma cell line studies. The results showed that addition of 900nM FA together with 40.4mM CBDCA enhanced the activity of the platinum compound, increasing its effect on cell death by nearly 20%, as evidenced by the MTT and NR assays. Moreover, not only higher levels of DNA and chromosomal damage were reached but also the number of necrotic and apoptotic cells were significantly increased when cell cultures were treated with the combined procedure. This situation opens the possibility to explore the use of FA in platinum-based chemotherapy protocols to reduce the platinum doses for patient treatment and decrease the chance of developing the known side effects without losing biological activity.

Vascularity and pain in the patellar tendon of adult jumping athletes: a 5 month longitudinal study.

BACKGROUND: This study investigated changes in tendon vascularity in 102 (67 men and 35 women) volleyball players over a 6 month competitive season. METHODS: Athletes were examined with both grey scale ultrasound and standardised colour Doppler settings. Vessel length and pain were measured each month on five separate occasions. Vascular tendons were divided into (i) those that were vascular on all occasions (persistent vascularity) and (ii) those that were vascular on more than two but less than five occasions (intermittent vascularity). RESULTS: A total of 41 of the 133 abnormal tendons were vascular on two or more occasions. Of these, 16 had persistent vascularity and 25 had intermittent vascularity. There was no significant difference in the prevalence of vascularity between men and women. None of the tendons had a pattern of vascularity over the season that could be clearly interpreted as the onset or resolution of vascularity. Subjects with changes in both tendons were more likely to have persistent vascularity (p = 0.045). Vessels were longer in tendons with persistent vascularity (p<0.000) and pain was significantly greater (p = 0.043) than in tendons with intermittent vascularity. Tendons with intermittent vascularity had similar pain scores on all days, whether or not they had detectable blood flow. CONCLUSIONS: These data suggest that the presence of blood vessels is more likely to be the source of pain than the blood flow in them.

High reproducibility of patellar tendon vascularity assessed by colour Doppler ultrasonography: a reliable measurement tool for quantifying tendon pathology.

BACKGROUND: This study examined whether patellar tendon vascularity could be quantified accurately in the clinical setting using colour Doppler ultrasonography. METHODS: A sonographer and two radiologists visually estimated tendon vascularity in millimetres in 74 tendons during ultrasound (US) examination and from hard copy films. These estimates were then compared to the length of vessels measured from the digital image in millimetres and the correlation between them was determined. A subset of 16 tendons was used to compare the estimates of vascularity by two examiners at US examination. RESULTS: The estimation of vascular length at US examination correlated highly with the measured vascular length (r = 0.92; 95% confidence interval (CI) 0.87 to 0.94), as did the length estimated from the films (r = 0.94; 95% CI 0.9 to 0.96). The correlation between examiners was 0.84 (95% CI 0.51 to 0.94) for the estimates made during US examination and 0.85 (95% CI 0.59 to 0.95) for the vessel lengths measured from the digital images. CONCLUSIONS: These excellent correlations indicate that tendon vascularity can be reliably estimated using colour Doppler ultrasonography and tendon vascularity could therefore be used by clinicians to rate clinical change. This method of quantifying tendon vascularity could also be used in research to investigate the effects of tendon treatments on vascularity.

Time course of recovery and heat acclimation ability of prior exertional heatstroke patients.

Our understanding of the time course of recovery from exertional heatstroke (EH) and the heat acclimation ability of prior EH patients is limited. This manuscript reviews previous findings regarding recovery from EH and presents original research involving the heat acclimation ability of 10 prior EH patients (PH) and 5 control subjects. Heat acclimation, by definition, distinguishes heat-intolerant from heat-tolerant prior heatstroke patients. Nine PH exhibited normal heat acclimation adaptations (40.1 degrees C, 7 d, 90 min.d-1), thermoregulation, sweat gland function, whole-body sodium and potassium balance, and blood values at 61 +/- 7 d after EH. One PH (subject A) did not adapt to exercise in the heat, was defined heat intolerant, but subsequently was declared heat tolerant (11.5 months post-EH). Three PH exhibited large, unexpected increases in serum CPK levels, which resolved upon subsequent testing, and were probably related to their detrained state and the exercise which they performed. It was concluded that: 1) sleep loss and generalized fatigue were the most common predisposing factors for PH; 2) recovery from EH was idiosyncratic and may require up to 1 year in severe cases; 3) PH were not hereditarily heat intolerant, prior to EH; 4) no measured variable predicted recovery from EH, or heat acclimation responses; 5) heat intolerance occurs in a small percentage of prior heatstroke patients, and may be transient or persistent.

The induction of reciprocal translocations in mouse germ cells by chemicals and ionizing radiations. I. Dose-response relationships and combined effects of bleomycin with thio-tepa and gamma-rays.

The effect of bleomycin (BLM) on mouse stem cells has been analysed using the spermatocyte test. The dose-response relationships after treatment with doses of 20, 40 and 60 mg/kg of the compound as well as the combined effect of BLM and gamma-rays and BLM and thio-tepa (TT) were studied. A positive, significant correlation between the dose of BLM and the frequency of translocations was found. Two different responses were found when the yields of translocations induced after combined treatments, separated by a lapse of 24 h, were compared with the sum of translocation frequencies induced after the corresponding single treatments: (1) Potentiation, in the treatments with 1 Gy plus 9 Gy and 60 mg/kg of BLM plus 9 Gy; (2) additivity, in the treatments with 60 mg/kg of BLM plus 1 Gy, 1 Gy plus 60 mg/kg of BLM, and 0.2 mg of TT plus 60 mg/kg of BLM. In mice irradiated with 1 Gy plus 9 Gy and mice treated with 60 mg/kg of BLM plus 9 Gy, similar translocation yields were found. The potentiating effect of BLM is similar to that obtained with non-radiomimetic compounds such as triethylenemelamine, cyclophosphamide and adriamycin. These results are discussed taking into account the hypothesis of germ cell selection, and the dose of radiation employed.

The kinetics of DNA damage by bleomycin in mammalian cells.

The kinetics of DNA damage by bleomycin (BLM) was assessed by measuring the amount of DNA breakage induced by BLM at different doses, treatment lengths, and treatment temperatures. DNA degradation was measured with the alkaline unwinding method. Comparison of the curves of DNA cleavage by BLM leads to the conclusion that low doses (1-5 micrograms/ml) and short treatments (5-15 min) produce marked damage in the DNA. High increases in BLM concentration produce relatively small increases in DNA damage above the levels obtained with low doses. Extension of treatment times does not increase the DNA degradation above the rate observed with 15-min treatments. The repair of DNA damage starts at about 15 min after the initiation of treatment. The mending of DNA breaks is very fast and extensive when BLM is no longer present. Repair not only implies the closing of DNA nicks, but very likely the degradation of the BLM molecules intercalated in the DNA interrupting the reactions responsible for the generation of free radicals. Persistence of BLM in the cell environment facilitates the replacement of degraded BLM molecules by new ones. This produces the persistent production of free radicals and the establishment of a balance between the processes of DNA damage and repair.

The induction of reciprocal translocations in mouse germ cells by chemicals and ionizing radiations. III. Differential effect of two doses of adriamycin combined with 5 or 9 Gy of gamma-rays.

The induction of reciprocal translocations in mouse germ cells by combined treatments with chemicals and ionizing radiations has been studied. Male mice were intraperitoneally injected with doses of 5 or 10 mg/kg of adriamycin (ADR) and irradiated with doses of 5 or 9 Gy of gamma-rays 24 h later. Three types of response were found after analyzing diakinesis-metaphase I multivalent configurations: potentiation, with the dose of 5 mg/kg of ADR plus 9 Gy; subadditivity, with the dose of 5 mg/kg of ADR plus 5 Gy; and additivity, with the dose of 10 mg/kg of ADR plus 5 or 9 Gy. According to these results, the subadditive effect observed with the lower dose of ADR plus 5 Gy cannot be explained under the assumption that depletion of any kind of spermatogonia is sufficient for modifying the chromosomal response of stem cells to ionizing radiations. The role of DNA repair mechanisms modulating the response of spermatogonial cells to combined treatments is discussed under the assumption that some repair mechanisms can be triggered by treatment with a low dose of a chemical and these repair mechanisms can reduce cell mortality. Consequently, a higher frequency of more radioresistant cells can survive.

The induction of reciprocal translocations in mouse germ cells by chemicals and ionizing radiations. II. Combined effects of mitomycin C or thio-tepa with two doses of gamma-rays.

The combined effects of mitomycin C (MMC) and thio-tepa (TT) with gamma-ray doses of 5 and 9 Gy on mouse stem cells were studied using the spermatocyte test. Both chemicals induced very low yields of translocations after single treatments. In combined treatments with a dose of 5 Gy, a subadditive effect of MMC and an additive effect of TT were found. Combined with a dose of 9 Gy the compounds potentiated the effect of radiations. Up to now, most of the chemicals tested have shown additive effects when combined with doses of the ascending part of the dose-response curve and potentiating effects when combined with doses of its descending part. This has been considered additional confirmation of the concept that depletion of any kind of spermatogonia is sufficient to modify the genetic response of stem cells. However, the subadditive and additive responses found could be considered evidence that common biological mechanisms can modulate the response to combined treatments of chemicals and ionizing radiations.

DNA damage induced by copper deficiency in cattle assessed by the Comet assay.

Cattle hypocuprosis is a well-known endemic disease in several parts of the world. In a previous paper, the clastogenic effect of copper deficiency in cattle has been described although the occurrence of DNA damage was not directly tested. For this reason, the relation between DNA damage assessed by the Comet assay and Cu plasma concentration was studied in Aberdeen Angus cattle. Blood samples were obtained in heparinized Vacutainer tubes from 28 female Aberdeen Angus cows during pregnancy or immediately after to give birth. Each sample was divided into two aliquots for Comet assay and Cu plasma determination, respectively. From the 28 cattle sampled, 17 were normocupremic and 11 were hypocupremic. Results obtained showed that whereas the average plasma Cu level in normocupremic cattle was 67.6 microg/dl, in hypocupremic cattle it was 32.1 microg/dl. The increase of DNA damage was mostly evidenced by the decrease of comet degree 1 cells and an increase of comet degree 2 cells. Correlation analysis comparing plasma Cu levels and degree 1 cells showed a correlation coefficient 0.72 (P<0.01). The comparison between plasma Cu levels and comet degree 2 cells was -0.65 (P<0.01). The comparison between plasma Cu levels and the comet length-head diameter medians determined in 23 out of 28 animals showed a correlation coefficient of -0.54 (P<0.01). The induction of DNA damage was clearly supported by the fact that the decrease of plasma Cu levels was correlated with the increase of comet length-head diameter. These findings could be considered as a contribution to the hypothesis that DNA and chromosome damage are a consequence of the higher oxidative stress suffered by hypocupremic animals.

Clastogenic effect of copper deficiency in cattle.

Copper plays an essential role as a micronutrient. Deficiency of this element (hypocuprosis) in experimental and domestic animals has a severe impact on growth as well as on reproduction. The occurrence of lesions during hypocuprosis is correlated with the depletion of an enzymatic group in which copper takes part. The aim of this work was to analyse chromosomal aberrations in Aberdeen Angus cows of the province of Buenos Aires in relation with the Cu plasma levels. Short term lymphocyte cultures were made from samples obtained from four groups of animals: two groups with normal levels of copper in plasma and two groups with severe hypocupremia. This analysis showed a significant increase of the frequency of chromosomal aberrations (p<0.001) in the hypocupremic groups in relation with control groups. Finally, the Spearman correlation analysis showed a significant negative association (p<0.05) between copper levels and the yield of chromosomal aberrations. The increase of the frequencies of chromosomal aberrations found in the hypocupremic groups could be explained by the higher oxidative stress suffered by these animals. A lower catalytic activity of enzymes such as Cu/Zn superoxide dismutase (Cu/Zn-SOD) and cytochrome-c oxidase could increase the intracellular production of active oxygen species (O(2)(-), H(2)O(2) and OH(o)) with the consequent clastogenic effects.

Chronic fatigue syndrome beginning suddenly occurs seasonally over the year.

The fact that many patients with chronic fatigue syndrome (CFS) have an infectious like sudden onset to their illness has led to the hypothesis that CFS is a medical illness. If CFS were, on the other hand, a psychiatric disorder related to symptom amplification, one would expect illness onset to occur randomly over the calendar year. This study tested that hypothesis with 69 CFS patients whose illness was on the more severe side of the illness spectrum; all patients reported sudden illness onset with the full syndrome of sore throat, fatigue/malaise, and diffuse achiness developing over no longer than a 2-day period. Date of illness onset was distinctly nonrandom. It peaked from November through January and was at its lowest from April through May. These data support the hypothesis that an infectious illness can trigger the onset of CFS.

Y-Chromosome morphology and incidence of the 1/29 translocation in argentine creole bulls.

The Argentine Creole is a local breed of cattle with high reproductive performance. This breed also shows resistance to many subtropical diseases. The cytogenetic status of the Argentine Creole, in particular the incidence of 1/29 translocation and Y-chromosome morphology, is not known in Argentina. Taking these factors into account, the cytogenetic study of 36 Argentinian Creole bulls was carried out. Heparinized blood samples were obtained and cultured for chromosome analysis. The results showed the absence of the 1/29 translocation in all the bulls analyzed and the presence of a submetacentric Y chromosome.

Incidence of 1/29 translocation in Bolivian Creole and Brahman Yacumeño cattle.

In Bolivia, four different Creole cattle breeds can be found, as well as other European and Zebu breeds adapted to local environments. The relationship between the occurrence of the 1/29 translocation and subfertility is well known, and analysis of Y chromosome morphology is useful to determine a possible introgression with Bos indicus. The incidence of the 1/29 translocation was analyzed in four Bolivian Creole cattle breeds and the Brahman Yacumeño population, as well as on four farms with phenotypical Creole-type cattle. In 259 (164 dams and 95 sires) Bolivian Creole cattle, 10.42% of the individuals demonstrated the 1/29 translocation, with a variation from 0 to 28.20% between the breeds. In contrast, 43 (19 dams and 24 sires) Yacumeño Brahman and the Creole-type cattle did not show the centric fusion. The highly significant differences between Creole cattle breeds in relation to the incidence of 1/29 translocation could be a consequence of factors such as founder group, genetic drift, and selection. The low frequency observed in the Saavedreñio Creole dairy cattle might be explained by its breeding under a more intensive system, and selection according to milk yield and fertility traits. Finally, no relation between acrocentric Y chromosomes and 1/29 translocation was observed.

Time scale to ergodicity in the Fermi-Pasta-Ulam system.

We study the approach to near-equipartition in the N-dimensional Fermi-Pasta-Ulam Hamiltonian with quartic (hard spring) nonlinearity. We investigate numerically the time evolution of orbits with initial energy in some few low-frequency linear modes. Our results indicate a transition where, above a critical energy which is independent of N, one can reach equipartition if one waits for a time proportional to N(2). Below this critical energy the time to equipartition is exponentially long. We develop a theory to determine the time evolution and the excitation of the nonlinear modes based on a resonant normal form treatment of the resonances among the oscillators. Our theory predicts the critical energy for equipartition, the time scale to equipartition, and the form of the nonlinear modes below equipartition, in qualitative agreement with the numerical results. (c) 1995 American Institute of Physics.

Patagonian Argentine Creole cattle polymorphism: comparison with North-West populations of this breed.

The relict Patagonian Argentine Creole cattle population consist of a small feral population (Los Glaciares population) that is geographically isolated in the South-West of Patagonia. In order to determine the level of genetic variability of this population, the polymorphism of eight structural genes and two microsatellites loci were studied using the polymerase chain reaction (PCR). In addition, genetic characterisation was used to compare Los Glaciares population and the ACc breed of cattle. Results obtained in this study show that the value of average heterozygosity of the studied loci for the Los Glaciares were not significantly different from the ACc. Furthermore, the data of this report were consistent with the hypothesis that Los Glaciares originated from ACc brought to the area by colonialists in the last century. Such data may be useful in formulating management plans for Feral Patagonian Creole cattle populations.

The effect of a hypoproteic diet and ethanol consumption on the yield of chromosomal damage detected in bone marrow cells of mice.

The relationship between protein malnutrition and ethanol consumption as modulating factors of the genetic response to xenobiotics was studied. BALB/c mice of both sexes were fed for three weeks after weaning either with a normal diet containing 25% protein or a hypoproteic diet containing 5% protein. Half of the animals received 20% ethanol in drinking water. Cytogenetic analysis was performed in bone marrow cells. Slides were stained for C-banding in order to assure the accurate scoring of dicentric chromosomes. Results obtained showed an increased frequency of dicentric chromosomes in mice fed with the hypoproteic diet (5.45 dicentrics per 100 cells) in contrast to mice fed with the normal diet (0.61 dicentrics per 100 cells). Ethanol consumption increased the frequency of chromosomal damage, but no differences in the effect of ethanol between mice fed with the normal diet and mice fed with the hypoproteic diet (16.33 and 16.80 dicentrics per 100 cells respectively). The enhanced frequency of dicentric chromosomes in animals fed with the hypoproteic diet might have been originated from the increase or the improper repair of chromosome breaks. The similarity in the response to ethanol consumption in animals fed either with the normal or the hypoproteic diet might have been provoked by a decrease of alcohol dehydrogenase (ADH) level in undernourished mice. The chromosomal damage due to ethanol may be lower in undernourished mice than in mice fed with the normal diet due to the reduced amount of circulating acetaldehyde able to induce chromosomal damage. The results obtained are an evidence of the role played by the diet in the modulation of the genetic response to xenobiotics.

The relation between protein malnutrition, ethanol consumption and chromosomal damage induced by cyclophosphamide in bone marrow cells of mice.

The effect of protein malnutrition and alcohol consumption on the yield of chromosomal damage induced by cyclophosphamide (CP) was studied. Chromosomal damage induced in bone marrow cells of BALB/c mice was established by scoring the frequency of dicentric chromosomes in C-banded slides. Results obtained showed that CP induced a significant increase of chromosomal damage in comparison with untreated mice. In addition, the yield of dicentric chromosomes was higher in mice fed with the hypoproteic diet. The animals which received ethanol in drinking water before treatment with CP exhibited the highest frequency of dicentric chromosomes, with no relation with the diet. Statistical analysis of these results showed the additive effect of diet and CP and are explained taking into account the metabolic pathways of CP as well as the decrease of enzymatic levels and the physiological condition in under-nourished mice.