Teratogenicity of elevated egg incubation temperature and egg vitamin A status in Atlantic salmon, Salmo salar L

The present study was undertaken to investigate the possibility that high egg vitamin A (VA) status in combination with elevated egg incubation temperatures may cause deformities in Atlantic salmon, Salmo salar L. Egg batches selected for their total VA concentration were exposed to low (normal, 8 degrees C) or elevated (14 degrees C) egg incubation temperatures. Temperature was the main factor causing bone deformities such as warped gill opercula, fin and jaw deformities, but not for the development of spinal deformities where all groups displayed a 'baseline' occurrence of mild deformity (decreased vertebral size in the cephalic region) and no systematic variation in the occurrence of serious spinal deformities (fused vertebrae). A possible effect of egg incubation temperature fluctuation was found for the groups reared at low temperatures. An indication of a negative effect of elevated egg VA status for the development of organ deformities such as missing septum transversum and situs inversus was found in addition to temperature effects, however, no firm conclusions could be drawn from the present data. The phenotypes for temperature-induced deformities resembled the phenotype of VA-induced deformities, but no clear conclusions on the causality of the deformities found in the present study could be drawn. Egg incubation temperatures, both absolute temperature and temperature variations, should therefore be strictly controlled.

Structures of a continuously fed two-dimensional viscous film under a destabilizing gravitational force

We study the gravity induced instability of a liquid film formed below a plane grid which is used as a porous media in an original hydrodynamic experiment. The film is continuously supplied with a controlled flow rate. We give through a phase diagram the full spectrum of the different flow regimes and we investigate the dynamics of the observed structures. True secondary instabilities of a 2D periodic pattern are described. The control parameters are the flow rate and the viscosity.

Effect of the extender supplement Equex-STM on cryopreserved semen in the Assaf sheep

This study was designed to evaluate the effect of adding the detergent Equex-STM to the extender used to dilute semen for cryopreservation on several indicators of sperm preservation. Two consecutive ejaculates per day were obtained from 5 Assaf sheep on two days out of every week over three alternate months. The freezing protocol involved diluting the semen in Fiser's extender, to which 0.7 percent Equex-STM was added or omitted before cryopreserving the semen in straws by exposure to nitrogen vapor. Equex-STM supplementation gave rise to significantly (p=0.05) improved sperm quality variables after different periods of freezing (0 hours, 1 week and 1 month). The variables examined were: individual motility, viability, acrosome integrity, plasma membrane integrity (HOS test) and morphological anomalies. This improvement was independent of the ram and month of testing. In a second experiment in which we incubated the semen (0 and 6 hours) at 37 degree C after thawing, Equex-STM also showed a beneficial effect on sperm quality.

[Treatment with desmopressin before epidural anesthesia in a patient with type I von Willebrand disease]

A 33-year-old primipara with von Willebrand disease type I was admitted in labor at 37 weeks, requesting epidural analgesia. The consultant hematologist advised treating with desmopressin acetate (DDAVP) before inserting an epidural catheter. Desmopressin at a dose of 0.3 microgram/Kg was administered intravenously and the catheter was inserted to L3-L4 to infuse 0.1% bupivacaine with 2 micrograms/mL of fentanyl at a rate of 12 mL/h. Four hours later the patient was brought to the operating room for forceps delivery of a healthy boy. One hour later, she had recovered normal motor tone followed by normal sensitivity in the lower extremities. The catheter was then withdrawn with no signs of bleeding. A woman with von Willebrand's disease can receive an epidural block for analgesia during childbirth. The decision to perform the block should be individualized, based on coagulation tests. DDAVP may play a role in improving hemostasis.

Complex population genetic structure in the endemic Canary Island pine revealed using chloroplast microsatellite markers

The Canary archipelago, located on the northwestern Atlantic coast of Africa, is comprised of seven islands aligned from east to west, plus seven minor islets. All the islands were formed by volcanic eruptions and their geological history is well documented providing a historical framework to study colonization events. The Canary Island pine ( Pinus canariensis C. Sm.), nowadays restricted to the westernmost Canary Islands (Gran Canaria, Tenerife, La Gomera, La Palma and El Hierro), is considered an old (Lower Cretaceous) relic from an ancient Mediterranean evolutionary centre. Twenty seven chloroplast haplotypes were found in Canary Island pine but only one of them was common to all populations. The distribution of haplotypic variation in P. canariensis suggested the colonization of western Canary Islands from a single continental source located close to the Mediterranean Basin. Present-day populations of Canary Island pine retain levels of genetic diversity equivalent to those found in Mediterranean continental pine species, Pinus pinaster and Pinus halepensis. A hierarchical analysis of variance (AMOVA) showed high differentiation among populations within islands (approximately 19%) but no differentiation among islands. Simple differentiation models such as isolation by distance or stepping-stone colonization from older to younger islands were rejected based on product-moment correlations between pairwise genetic distances and both geographic distances and population-age divergences. However, the distribution of cpSSR diversity within the islands of Tenerife and Gran Canaria pointed towards the importance of the role played by regional Pliocene and Quaternary volcanic activity and long-distance gene flow in shaping the population genetic structure of the Canary Island pine. Therefore, conservation strategies at the population level are strongly recommended for this species.

Susceptibility and exposure biomarkers in people exposed to PAHs from diesel exhaust

Xenobiotic metabolizing enzymes, especially CYP1A1 and GSTM1, are involved in the activation and conjugation of PAHs and are controlled by polymorphic genes. PAHs released from diesel emissions in many cities of the world, especially in developing countries, contribute significantly to the toxic effects of airborne inhalable particles. We have evaluated the gene-environment interaction in Santiago of Chile, studying the contribution of CYP1A1 and GSTM1 polymorphisms on 1-OH-P urinary levels used as the PAHs exposure biomarker. The study was performed on 59 diesel exposed (38 diesel revision workers and 21 subjects working in an urban area as established street vendors) and 44 non-exposed subjects living in a rural area. The 1-OH-P urinary levels of the urban (P=0.043) and rural (P=0.040) populations showed, without considering the genotypes, significant differences between smokers and non-smokers, but no significant differences were found between smokers and non-smokers among the diesel plant workers (P=0.33). Non-smoking subjects of the diesel plants and the urban area showed similar 1-OHP levels (P=0.466) which were significantly higher than those of the subjects living in the rural area (P<0.05). When 1-OH-P levels were related with genotypes, an association was observed for the CYP1A1*2A genotype, so that the diesel-exposed workers carrying the CYP1A1*2A allele showed significantly higher 1-OH-P levels than the subjects from the rural area with the same genotype (P=0.008). On the other hand, there was no significant correlation between urinary 1-OH-P levels and GSTM1 null genotype, although higher levels of the urinary metabolite were found in individuals carrying the combined CYP1A1*2A and GSTM1 null genotype (P=0.055). These results may suggest an association between levels of the exposure biomarker 1-OH-P and presence of the CYP1A1*2A genotype, a potential genetic susceptibility biomarker which might be useful in identifying individuals at higher risk among people exposed to high PAH levels in diesel exhaust.

Methotrexate cytotoxicity on MCF-7 breast cancer cells is not altered by exposure to 25 Hz, 1.5 mT magnetic field and iron (III) chloride hexahydrate

The action of electromagnetic fields (EMF) on different pathways related to cell physiology, proliferation, toxicity of chemicals, gene expression, etc., are currently being investigated although the results are still not conclusive and even conflicting. In laboratory and animal studies, EMF has been found to produce a great variety of effects such as: increase in ornithine decarboxylase activity in breast, increase in beta-galactosidase gene expression and oncogene transcription after exposure to 50/60 Hz. Animal studies have shown that the use of EMF can enhance drug delivery across biological barriers (rat abdominal skin), using benzoic acid as the drug candidate. It has been reported by different authors that pulsed EMF (PEMF) can produce alterations in antineoplastic drugs potency. In the present study, we investigated the effects of PEMF on methotrexate cytotoxicity in MCF-7 breast cancer cells and the effects with simultaneous exposure to FeCl3. The data presented in the current report indicate that PEMF (25 Hz, 1.5 mT) do not induce modulation of the action of methotrexate (with and without iron-III) in MCF-7 cells when they are exposed to PEMF for 2 h/day during 3 days.

Female sterility in Ulmus minor (Ulmaceae): a hypothesis invoking the cost of sex in a clonal plant

A high incidence of individuals with low seed set was found in two populations of the field elm Ulmus minor, a European tree that reproduces sexually and via vegetative propagation through root sprouting. One population was a seminatural stand, while the other was established by artificial propagation of genotypes sampled widely across Spain. The low seed set in both populations was due to both pre- and post-zygotic factors, the importance of which vary between genotypes. These factors included gynoecial malformations that produced a non-ovulated pistil, early gynoecial necrosis (i.e., necrosis before any opportunities for pollination), and seed abortion. Female sterility gave rise to two classes of individuals: trees that were largely female-sterile but dispersed normal quantities of viable pollen, and trees that dispersed both normal pollen and substantial numbers of seeds. Reduced production of protein-rich seeds may increase the resource availability for clonal propagation, helping to maintain female-sterile individuals with hermaphrodites.

Influence of 1 and 25 Hz, 1.5 mT magnetic fields on antitumor drug potency in a human adenocarcinoma cell line

The resistance of tumor cells to antineoplastic agents is a major obstacle during cancer chemotherapy. Many authors have observed that some exposure protocols to pulsed electromagnetic fields (PEMF) can alter the efficacy of anticancer drugs; nevertheless, the observations are not clear. We have evaluated whether a group of PEMF pulses (1.5 mT peak, repeated at 1 and 25 Hz) produces alterations of drug potency on a multidrug resistant human colon adenocarcinoma (HCA) cell line, HCA-2/1(cch). The experiments were performed including (a) exposures to drug and PEMF exposure for 1 h at the same time, (b) drug exposure for 1 h, and then exposure to PEMF for the next 2 days (2 h/day). Drugs used were vincristine (VCR), mitomycin C (MMC), and cisplatin. Cell viability was measured by the neutral red stain cytotoxicity test. The results obtained were: (a) The 1 Hz PEMF increased VCR cytotoxicity (P < 0.01), exhibiting 6.1% of survival at 47.5 microg/ml, the highest dose for which sham exposed groups showed a 19.8% of survival. For MMC at 47.5 microg/ml, the % of survival changed significantly from 19.2% in sham exposed groups to 5.3% using 25 Hz (P < 0.001). Cisplatin showed a significant reduction in the % of survival (44.2-39.1%, P < 0.05) at 25 Hz and 47.5 microg/ml, and (b) Minor significant alterations were observed after nonsimultaneous exposure of cells to PEMF and drug. The data indicate that PEMF can induce modulation of cytostatic agents in HCA-2/1(cch), with an increased effect when PEMF was applied at the same time as the drug. The type of drug, dose, frequency, and duration of PEMF exposure could influence this modulation.

Population genetic structure in a Mediterranean pine (Pinus pinaster Ait.): a comparison of allozyme markers and quantitative traits

F-statistics were employed to analyse quantitative and allozyme variation among 19 native populations of maritime pine (Pinus pinaster Ait.). Fourteen polymorphic allozyme loci were used to provide an empirical basis for constructing a null hypothesis to test natural selection as a determinant of quantitative evolution in stem form, total height growth and survival at 30 years old. Hidden biases, that may result in a difference between quantitative (Q(ST)) and allozyme (F(ST)) differentiation which are not because of the action of natural selection, were avoided by comparing pairs of populations using linear models. All quantitative traits showed higher differentiation than allozymes. The highest divergence was found in stem form, whereas divergences in total height and survival were significantly lower. Differential adaptation to regional and local patterns of precipitation, temperature and soil type seem to be the best explanation of the different structure found in quantitative traits and allozyme loci. Possible bias in the estimation of Q(ST) due to the level of quantitative within-population diversity and the role of adaptation of maritime pine after the last glaciation to highly diverse ecological conditions are discussed with special reference to the actual geographical structure of gene diversity in the species' native range.

Enduring effects of environmental enrichment on novelty seeking, saccharin and ethanol intake in two rat lines (RHA/Verh and RLA/Verh) differing in incentive-seeking behavior

The Roman high- and low-avoidance (RHA/Verh and RLA/Verh) rat lines represent, respectively, low emotional/anxious and high novelty seeker vs. high emotional/anxious and low novelty seeker profiles. In the present study, RLA/Verh and RHA/Verh rats, either reared in pairs from weaning (untreated) or reared in groups of 8-10 in an enriched environment until the age of 7 months, were tested for exploratory and novelty-seeking behavior in the hole board (including novel objects under the holes), as well as for their preference for saccharin-water and ethanol-water in a two-bottle free-choice paradigm. Testing started when rats were 20 months old in order to study the long-lasting effects of differential rearing. RHA/Verh rats explored more and showed greater preference for (and intake of) saccharin as well as for ethanol than RLA/Verh rats, thus confirming their validity as a rat model for sensation/reward seeking. Environmental enrichment (EE) increased head-dipping behavior (i.e., novelty seeking) in both rat lines, without affecting locomotor activity. EE treatment increased the preference for, and volume intake of, saccharin (especially at the higher concentrations tested) in the relatively low saccharin-preferring RLA/Verh rats, and also enhanced ethanol consumption in both rat lines. Thus, the results demonstrate consistent and enduring effects of EE on incentive-seeking behavior and further the analysis of how individual differential predispositions for the need of novelty and contact with (or consumption of) rewarding substances arise through either biological (genetic) or early environmental factors, or both.

Influence of water stress on Dutch elm disease symptoms in Ulmus minor

The response of Ulmus minor Miller to Dutch elm disease was observed under combined heavy and light watering regimes. Ramets of two clones, planted in pots, were divided into two groups and each group underwent a different watering regime: heavy initial watering followed by light watering and light initial watering followed by heavy watering. The changeover in watering took place on May 29, 1998, 15 days after plants had been inoculated with a Ophiostoma novo-ulmi Brasier spore suspension. Greater wilting was evident in elms subjected to the heavy initial watering followed by light watering regime than those subjected to light initial watering followed by heavy watering. Non-inoculated plants subjected to heavy initial watering followed by light watering developed large vessel diameters during the heavy watering period and showed approximately 20% wilting during the light watering period. Non-inoculated plants subjected to light initial watering followed by heavy watering developed vessels with smaller diameters during the light watering period, and showed no wilting. The evidence suggests that large vessel formation prior to inoculation associated with water stress after infection increases Dutch elm disease symptoms. The role of water stress in the development of Dutch elm disease symptoms and the implications for elm resistance and breeding are discussed.Key words: field elm, Dutch elm disease, water relations, xylem vessels, breeding, Ophiostoma novo-ulmi.

Sum-frequency generation in dissipative systems: experimental evidence for optical wave patterns

We report a new mechanism for the secondary instabilities of traveling wave patterns in dissipative systems. In close analogy to nonlinear optics and plasma physics, it is a process of three-wave interaction that leads to sum-frequency generation. The primary traveling wave gives rise to two additional wave components, an upper and a lower frequency. We outline the mechanism and we show that this process does occur for wave patterns obtained in an optical experiment.

Seed gene flow and fine-scale structure in a Mediterranean pine ( Pinus pinaster Ait.) using nuclear microsatellite markers

The Mediterranean populations of maritime pine ( Pinus pinaster Ait.) are typically small and have a scattered distribution, being threatened by human activities and forest fires. In the framework of the genetic-resources conservation program of this species, a native multi-age stand located in a Mediterranean area (central Spain) was studied using three highly polymorphic nuclear microsatellites (SSRs). Spatial autocorrelation analysis was conducted using Moran's index in order to detect fine-scale structure in both natural regeneration and mature trees. The spatial pattern of seed flow based on dispersed progeny was studied using a highly reliable subset of parent-offspring matches obtained by means of parentage analysis and simulation-based calculation of statistical confidence. Maritime pine showed a fine-scale structure at the seedling stage. In natural regeneration, the autocorrelograms indicated a patch size of approximately 10 m. The fine-scale structure seems to be produced by a restricted seed gene flow. In fact, there was an excess of parent-offspring matches in a radius of 15 m from the parent trees. Pines with a heavy seed, such as P. pinaster, are expected to have a short dispersal distance, thus producing a fine-scale structure. However, the fine-scale structure did not persist in the mature trees. Within-population genetic structure in Mediterranean pines may be affected by a number of post-dispersal events (e.g. mortality due to the severity of the Mediterranean climate and animal-mediated secondary dispersal during the summer period). Thus, great alteration in the pattern produced by the initial seed rain and differences in genetic structure between tree cohorts are expected.

CYP1A1, CYP2E1 and GSTM1 genetic polymorphisms. The effect of single and combined genotypes on lung cancer susceptibility in Chilean people

CYP1A1, CYP2E1 and GSTM1 polymorphisms were evaluated in Chilean healthy controls and lung cancer patients. In the Chilean healthy group, frequencies of CYP1A1 variant alleles for MspI (m2 or CYP1A1*2A) and ile/val (val or CYP1A1*2B) polymorphisms were 0.25 and 0.33, respectively. Frequencies of variant alleles C (CYP2E1*6) and c2 (CYP2E1*5B) for CYP2E1 were 0.21 and 0.16, respectively and frequency for GSTM1(-) was 0.24. The presence of variant alleles for GSTM1, MspI and Ile/val polymorphisms was more frequent in cases than in controls. However, frequencies for the c2 and C alleles were not significantly different in controls and in cases. The estimated relative risk for lung cancer associated to a single mutated allele in CYP1A1, CYP2E1 or GSTM1 was 2.41 for m2, 1.69 for val, 1.16 for C, 0.71 for c2 and 2.46 for GSTM1(-). The estimated relative risk was higher for individuals carrying combined CYP1A1 and GSTM1 mutated alleles (m2/val, OR=6.28; m2/GSTM1(-), OR=3.56) and lower in individuals carrying CYP1A1 and CYP2E1 mutated alleles (m2/C, OR=1.39; m2/c2, OR=2.00; val/C, OR=1.45; val/c2, OR=0.48; not significant). The OR values considering smoking were 4.37 for m2, 4.05 for val, 3.47 for GSTM1(-), 7.38 for m2/val and 3.68 for m2/GSTM1(-), higher values than those observed without any stratification by smoking. Taken together, these findings suggest that Chilean people carrying single or combined GSTM1 and CYP1A1 polymorphisms could be more susceptible to lung cancer induced by environmental pollutants such as polycyclic aromatic hydrocarbons.

Selective oxidation of a keramaphidin B model

A crucial step in the Baldwin and Whitehead proposal for explaining the biogenesis of the marine alkaloid manzamine A is the selective oxidation of natural keramaphidin B to an iminium salt 3, which is then hydrolyzed to give the aldehyde 4. Conditions are now presented in which this selective oxidation can be performed on model compound 8, leading to the iminium salt 16. Although this salt can be considered as a model equivalent of the proposed aldehyde intermediate 4, it was found to be very resistant to hydrolysis as was the corresponding amide 20. From a synthetic point of view, the reported results illustrate the usefulness of the temporary protection of tertiary amines as aminoborane derivatives and constitute a good method for the oxidation of a sterically hindered tertiary nitrogen atom in the presence of a second nitrogen.

Active coatings for SiC particles to reduce the degradation by liquid aluminium during processing of aluminium matrix composites: study of interfacial reactions

The application of a surface coating on SiC particles is studied as an alternative means of solving problems of reactivity between SiC reinforcements and molten aluminium and problems of low wetting which limit the application of casting routes for fabrication of Al-SiCp composites. The selected active barrier was a ceramic composed of SiO2, which was generated by controlled oxidation of the SiC particles. The coating behaves as an active barrier, preventing a direct reaction between molten aluminium and SiC to form Al4C3 as the main degradation product. At the same time, the SiO2 provokes other interfacial reactions, which are responsible for an improvement in wetting behaviour. Composites were prepared by mixing and compacting SiC particles with Al powders followed by melting in a vacuum furnace, and varying the residence time. Transmission electron microscopy (TEM), high resolution electron microscopy (HREM) and field emission TEM were employed as the main characterization techniques to study the interfacial reactions occurring between the barrier and the molten aluminium. These studies showed that the SiO2 coating behaves as an active barrier which reacts with the molten Al to form a glassy phase Al-Si-O. This compound underwent partial crystallization during the composite manufacture to form mullite. The formation of an outer crystalline layer, composed mainly of Al2O3, was also detected. Participation of other secondary interface reactions inside the active barrier was also identified by HREM techniques.

[Indoor air pollution in a zone of extreme poverty of La Pintana, Santiago-Chile]

BACKGROUND

Indoor pollution can be an important risk factor for human health, considering that people spend more than 60% of their time in their houses.

AIM

To investigate indoor pollution in a zone of extreme poverty in Metropolitan Santiago.

MATERIAL AND METHODS

During 24 h, carbon monoxide (CO), sulfur dioxide (SO2), respirable particulate matter (PM10), polycyclic aromatic hydrocarbons absorbed in PM5, temperature and humidity, were measured in the interior of 24 houses in a La Pintana, Santiago.

RESULTS

The higher pollutant concentrations were observed during hours when heating was used, in houses that used coal (mean PM10 250 micrograms/m3, CO 42 ppm, SO2 192 pph) or firewood (mean PM10 489 micrograms/m3, CO 57 ppm, SO2 295 pph). In all houses, polycyclic aromatic hydrocarbons were detected and they came from the interior of the house and not from external filtered air. Coal, firewood and cigarette smoke were important sources of carcinogenic and kerosene and gas were sources of non carcinogenic polycyclic aromatic hydrocarbons.

CONCLUSIONS

In the houses studied, the population was exposed to an accumulation of highly toxic pollutants, caused by a lack of ventilation. A high relative humidity also contributed to the growth of biological pollutants.

25 Hz electromagnetic field exposure has no effect on cell cycle distribution and apoptosis in U-937 and HCA-2/1cch cells

It is reported that exposure to 50 Hz extremely low-frequency electromagnetic field (ELF-EMF) can produce apoptosis and small variations in cell cycle distribution on different cell lines. In order to study the effect of ELF-EMF on tumoral cells in vitro, two cell lines (U-937, from a histiocytic lymphoma, and HCA-2/1cch, from a human colon adenocarcinoma) were exposed to 25 Hz, 1.5 mT, for 2 h and 45 min. Cell cycle distribution, apoptosis (spontaneous and dexamethasone-induced) and cell growth were evaluated. Neither significant alteration in cell cycle phases nor induction of apoptosis was observed. Nevertheless, the relative cell number was found to decrease to 55.84+/-7.35% (p <0.05, Student's t-test) for HCA-2/1cch cells after exposure to EMF in the presence of dexamethasone. The presence of dexamethasone during the EMF exposure could probably produce a decrease in the cell growth of this cell line.