Acute and subacute toxicity of atrazine to carp (Cyprinus carpio L.)

Investigations of acute and subacute atrazine toxicity in carp (Cyprinus carpio L.) were carried out. Acute toxicity was investigated in a semi-static test during a 96-hr exposition. The estimated LC-50 value was 18.8 mg/l. Subacute toxicity was investigated by exposing fish (carp) to different atrazine concentrations (1.5, 3.0, and 6.0 mg/l) for 14 days. Biochemical and histopathological changes in certain organs and tissues were investigated. The results show that atrazine leads to changes of varying intensity depending on the parameter tested, the organs and tissues examined, as well as the atrazine concentration. Biochemical changes were most prominent in the alkaline phosphatase, glutamic-oxaloacetic transaminase, and glutamic-pyruvic transaminase activities whereas the most severe histopathological changes were observed in the gills.     

Occurrence of pesticides in Danish shallow ground water

Shallow ground water from four different catchment areas, two sandy and two clayey locations, were investigated for content of pesticides and -degradation products. The samples were taken from screens in extraction wells placed from 1.5 to 5 meters below surface 46 different compounds were included in the study, and the analysis were performed with liquid chromatography mass spectrometry (LC-MS) with detection limits below 0.01 microgram/L. In total more than 300 samples were analysed and the most frequently found compounds being atrazine and its degradation products, bentazone, MCPA, metamitron, isoproturon and simazine. 23 out of the 46 compounds were detected in one or more samples. Four different sulfonylurea herbicides were included in the study as they to some extent have substituted phenoxyacid herbicides in agricultural practice and in much lower dosage. Sulfonylurea herbicides did not occur in any samples.     

Relations between the nuclear activity and the variable 3H-amino acid incorporation pattern in Amoeba proteus

Tracer kinetic studies have revealed the existence of a variable pattern of 3H-amino acid incorporation into amoeba proteins during the early G2 phase of the cell cycle. Two peaks of incorporation of [3H]leucine were found to occur at 19 and 22 h, whereas a single peak at 17 h was noticed in the amoebae labelled with [3H]lysine. An almost 2-fold increase of the labelled amino acid incorporation occurred during the peak periods, while the other periods showed a more or less steady state of incorporation, suggesting a basal rate of synthesis at these times. In a detailed study involving the peaks and the basal incorporation period of [3H]leucine, it was shown that the removal of the nucleus or Actinomycin D treatment eliminated the peaks but the base line protein synthesis was not affected. This suggests that for the peak synthetic periods, mRNA is probably transcribed concurrently, followed by immediate translation, whereas long-life mRNA accounts for the basal synthetic activity.     

Two distinct forms of human mast cell chymase--differences in affinity for heparin and in distribution in skin, heart, and other tissues

Chymase, a chymotrypsin-like protease secreted by human mast cells, is generally considered to be a single enzyme. However, by heparin-agarose chromatography of high-salt extracts of human skin, we have consistently resolved three peaks of chymotryptic activity, eluting at 0.4 M NaCl (peak A), 1.0-1.2 M NaCl (peak B) and 1.8-2.0 M NaCl (peak C), with peak B containing 75-90% of the recovered activity. Each peak retained its identity upon rechromatography. The three peaks of activity were similar in substrate specificity and inhibitor profile and distinctly different from other chymotryptic enzymes, including cathepsin G and the stratum corneum chymotryptic enzyme. Examination of different tissues revealed that peak C was virtually absent from synovial tissue, was present as a minor component in skin and heart, but constituted the predominant chymotryptic activity in lung. Peaks B and C from skin tissue were further purified by chromatography on Sephacryl S-200. Both had a molecular mass of 28-29 kDa, yielded the N-terminal sequence reported for chymase, and on western blots reacted with a panel of polyclonal, monoclonal and antipeptide antibodies against chymase. Chymase C required higher concentrations of NaCl to overcome the stimulatory effects of heparin than did chymase B, but had a similar pH profile. Thus, human chymase exists in at least two distinct but similar forms, and the differences in heparin binding and tissue distribution could have important consequences for enzyme function.     

The influence of thermomechanical treatment on the complex modulus of Mg alloy AZ31

Dynamic modulus analyses were performed on Mg alloy AZ31 following thermomechanical treatments to enable investigation of the influence of microstructural features created by plastic deformation on the elastic and the anelastic behavior of this alloy as quantified by variations in the complex elastic modulus (E* = E′ + iE″) with temperature. The real component or storage modulus (E′) determined for this alloy was 42.0 ± 2.5 GPa at 25 °C and it was independent of rolling direction and cold work up to 20 pct reduction in thickness. A broad peak was observed in the imaginary component or loss modulus (E″) around 175 °C (for a 1.0 Hz loading frequency), and it was determined that this peak is a superposition of at least four different relaxation mechanisms: a thermally activated mechanism related to precipitate phases near 153 °C and three peaks related to mechanical deformation at 165 °C, 188 °C, and 235 °C. The latter three peaks were also thermally activated with the activation energy determined to be 1.68 ± 0.04 eV. These mechanical relaxation peaks are attributed to microstructural features produced by cold work, and it is demonstrated that the stresses generated by cooling from heat-treatment temperatures influences these peaks. It is concluded that the grain boundary relaxation peak is above 350 °C.     

Cortical potentials time-locked to EKG-R waves during wakefulness and slow wave sleep (stage 2) in the mankind (author's transl)

The purpose of this paper was to investigate whether cardiovascular afferent impulses could be recorded on a human scalp as computer-averaged cortical potentials time-locked to EKG-R waves. The results obtained were as follows. 1) Cortical potentials time-locked to EKG-R waves (EKG-EP) could be recorded on scalps of eleven healthy volunteers and within its pattern, triple negative large peaks could be seen during both wakefulness and slow wave sleep (stage 2). 2) Within triple negative large peaks, the 2nd negative peak were most stable and its averaged latencies were 224.1 +/- 32.4 msec. during wakefulness and 257.1 +/- 76.7 msec. during slow wave sleep (stage 2) and the 3rd negative peak had been found more frequently in the slow wave sleep than in the wakefulness. 3) EKG-EPs were analogous with those of auditory evoked potentials time-locked to EKG-R waves (EKG-AEP) if both were recorded in the same concious level. 4) Both latencies of the 2nd negative peak of the EKG-EPs and that of the largest negative peak of the EKG-AEPs were consistent each other with high ratio resulting r = 0.81 (P less than 0.01) in the wakefulness and r = 0.966 (P less than 0.001) in the slow wave sleep (stage 2) respectively.     

Monitoring ovarian cycle and pregnancy in the giant anteater (Myrmecophaga tridactyla) by faecal progestagen and oestrogen analysis

Oestrogen and progestagen metabolites were measured in the faeces of five female giant anteaters (Myrmecophaga tridactyla), to characterise the oestrous cycle and pregnancy. Faecal samples were collected twice weekly for a minimum of 6 months, and immunoreactive progestagens and oestrogens were analysed using enzyme immunoassays (EIA). For progestagens, two antibodies that cross-reacted with 20alpha-hydroxy- or 20-oxo-progestagens were used. Both assays effectively monitored ovarian cyclicity; however, the concentrations obtained using the antibody for 20alpha-hydroxy-progestagens were higher, and the hormonal changes were more pronounced. Regular ovarian cycles were identified in three of the five females. Average (+/-SEM) length of the oestrous cycle (n=10) was 51.4+/-5.6 days. Peak concentrations of 20alpha-hydroxy-progestagens ranged from 80-660 ng/g of faeces and those of oestrogens from 20-100 ng/g. Hormone concentrations were measured during parts of two pregnancies and during four post-partum periods. The length of one gestation (from oestrous oestrogen peak until parturition) was 184 days. In the second half of gestation, progestagen concentration started to increase above luteal phase values; in the week before parturition it was approximately 20 times higher than those during the luteal phase. Concentrations of excreted oestrogens began to increase after two thirds of gestation and exceeded that of the follicular phase by approximately 2.5-fold in the week before parturition. Onset of ovarian cyclicity after parturition varied from 4-11 weeks. In conclusion, the measurement of faecal immunoreactive progestagens and oestrogens in the giant anteater indicated an ovarian cycle of approximately 7 weeks in length and provided potentially useful data for successful breeding management.     

Simultaneous quantitative gas-chromatographic analysis of ethosuximide, phenobarbitone, primidone and diphenylhydantoin

1 Therapeutic serum concentrations of ethosuximide, phenobarbitone, primidone, and dipheylhydantoin were assayed from 1 ml of human serum. The extraction procedure was common to all four drugs and three internal standards. 2 Subsequent isothermal gas chromatographic analysis of serum extracts produced well resolved peaks for the underivatized quantitation of ethosuximide and phenobarbitone. Primidone and diphenylhydantoin were determined as methylated derivatives. 3 Mean coefficients of variation for the assay of each drug were less 7% on a newly packed and conditioned column and less than 10% after the technique had been in continuous use for 3 months. 4 The advantage of quantitation relative to peak area ratios rather than peak height ratios was minimal for the determination of ethosuximide, primidone and diphenylhydantoin but appeared significant for the assay of phenobarbitone.     

Crossover study of the haematological effects and pharmacokinetics of glycosylated and non-glycosylated G-CSF in healthy volunteers

A cross-over study of glycosylated and non-glycosylated G-CSF was performed in 20 healthy male volunteers to compare the effects of the different forms of G-CSF, the extent of inter-individual progenitor cell mobilization and to determine whether any differences observed were related to the serum concentrations of G-CSF attained. The peak WBC achieved during 6 d of G-CSF administration at a dose of 5 microg/kg/d was significantly higher with the glycosylated than the non-glycosylated product (P = 0.02) as was the peak level of granulocyte-monocyte colony forming cells (GM-CFC) (P=0.03). The average GM-CFC count on days 5, 6 and 7 was 28% higher with the glycosylated product (P=0.003). Serum concentrations of G-CSF achieved were significantly higher with the non-glycosylated G-CSF, however, suggesting that the difference in bio-efficacy was not due to a difference in G-CSF stability. Marked inter-individual variation in progenitor mobilization was observed, but this was not related to serum G-CSF levels. The G-CSF concentrations on day 6 were approximately one third of those on day 1, with both forms of G-CSF.     

Aquatic Assessment of the Chernobyl Nuclear Accident and Its Remediation

This modeling study evaluated the aquatic environment affected by the Chernobyl nuclear accident and the effectiveness of remediation efforts. The study results indicate that radionuclide concentrations in the Pripyat and Dnieper rivers were well above the drinking water limits immediately after the Chernobyl accident but have decreased significantly in subsequent years due to flushing, burying, and decaying. Because high concentrations of 90Sr and 137Cs, the major radionuclides affecting human health through the aquatic pathways, are associated with flooding, two earthen dikes were constructed along the Pripyat River. The left-bank dike alone was successful in reducing the 90Sr concentration in the river by half. The 100-m-high, movable New Safe Confinement (NSC), which will cover the current Chernobyl Shelter, will reduce radionuclide contamination further in these rivers and nearby groundwater. If the Chernobyl Shelter should collapse before the NSC is built, the resulting peak radionuclide concentrations in the Dnieper River are expected to still remain below the drinking water limits. The radionuclide influx to groundwater through the NSC should not have any effect on concentrations in the Pripyat River.     

Behavioral responses to atrazine and diuron in goldfish

Experiments were performed in goldfish to determine the effects of a short-term exposure (24 h) to atrazine or diuron (0.5, 5, 50 microgram/L) on some behavior endpoints related to swimming and social activities. Observations were also made to assess the influence of such exposure on the behavioral responses of fish to the flow of a crude skin extract solution from conspecifics, active in social chemocommunication and producing alarm behaviors. Additive tests were run to check the behavioral responses of previously unexposed goldfish to the flow of a solution of atrazine- or diuron-contaminated water, at three concentrations (0.1, 1, 10 mg/L). Significant burst swimming reactions appeared in response to a 24-h exposure to atrazine, at the lowest concentration tested (0.5 microgram/L). A 24-h exposure to 5 microgram/L atrazine or diuron was found to induce various significant behavioral alterations in fish. At this concentration, both herbicides decreased grouping behavior and atrazine also increased surfacing activity. Herbicide-exposed fish showed a decreased grouping behavior during the flow of the skin extract solution. Sheltering was also decreased during the flow of the biological solution in fish exposed to atrazine. Moreover, fish exposed to diuron clearly displayed attraction responses to the flow of the skin solution. Previously unexposed fish showed a significant increase in burst swimming reactions in response to the flow of a solution of atrazine- or diuron-contaminated water, at all concentrations tested (0.1, 1, 10 mg/L). Furthermore, the diuron-contaminated flow was found to be significantly attractive at the highest concentration. These results indicate that a short-term exposure to a relatively low concentration (5 microgram/L) of atrazine or diuron can affect various behaviors of fish not only directly but also indirectly by altering the chemical perception of natural substances of eco-ethological importance. In consideration of the basic role of olfaction in fish behavior, these results also emphasize the need for further developments on the possible effects of aquatic toxicants on olfactory-mediated behaviors.     

Plasma LH progesterone concentrations in the turkey hen during the ovulatory cycle

Progesterone and luteinizing hormone (LH) were measuured in the plasma of Large White turkey hens at frequent intervals during the ovulatory cycle and during the periods when ovulations did not occur. The hormones were quantitated at the beginning and the end of the reproductive season to follow the change in patterns and concentrations of these hormones. Radioimmunoassay procedures were used to assay both hormones. Both progesterone and LH reached a peak amount at about 8 to 2 hours before ovulation. At no time did the progesterone peak precede that of LH. On the other hand, the peak of progesterone was observed to last somewhat longer than the LH peak. Progesterone and LH concentrations demonstrated no peak during the non-ovulatory periods. The patterns of both hormones at the end of the reproductive season was about the same as at the beginning of the season, but with lower concentrations.     

Comparative effect of embryonic mouse fibroblasts (Balb/c-3T3) on the proliferation of hormone-dependent (T-47D) and hormone-independent (MDA-MB-231) human breast cancer cell lines

An increase in the intensity and distinct spectral changes of ultraweak luminescence from the yeast Saccharomyces cerevisiae were measured when the metabolism of cells was drastically altered. A small emission peak and a red emission band 680-850 nm appeared when air-dried cells were imbibed in water. Lethal concentrations of HCHO (0.01%-10%) elicited a 2500 fold increase of the emission intensity and distinct spectral alterations. A transient 500-580 nm emission appeared in the initial phase of interaction. Then a gradually increasing long-lasting red emission band centered around 620 nm predominated in the total spectral range covering 470-850 nm. These emissions were not correlated with minor changes in fluorescence emission and excitation spectra originating from tryptophan, flavins, and unidentified emitters.     

Event-related potential measures of information processing during general anesthesia

To investigate the incidence and manner of auditory information processing during a state of presumed unconsciousness event-related brain potentials (ERPs) were studied in 41 patients undergoing cardiac surgery with propofol/alfentanil anesthesia. The ERPs were recorded during auditory oddball tasks administered before and within several periods of the operation. Mean nasopharyngeal temperature and anesthetic concentrations were determined for each intraoperative ERP recording epoch. During anesthesia ERP waves could still be observed up to 500 ms after stimulus onset indicating that auditory information processing was not suppressed completely by the administered anesthetic agents. Relative to the preoperative recordings, the P1-N1-P2 complex was delayed and more positive going during anesthesia. Comparable changes in ERP morphology have been observed during Stage II-IV sleep, suggesting parallels in the mechanisms underlying early auditory processing in both states of reduced arousal level, possibly related to a selective reduction of a non-specific activity. N1 and P2 peak amplitudes were found to be larger for the deviant tones compared to the standard tones. These amplitude differences most likely reflect automatic detection of stimulus deviance, although it cannot be excluded entirely that they were due to differences in refractoriness. Anesthetic concentrations and nasopharyngeal temperature were found to be of minor significance for ERP control. It is suggested that ERPs could serve as intraoperative reference measures, providing the earliest evidence for auditory processing. This characteristic is important for validation of signals and techniques that are proposed to improve conventional monitoring of anesthesia with respect to detecting unintended awareness.     

DNA damaging effects of pesticides measured by the single cell gel electrophoresis assay (comet assay) and the chromosomal aberration test, in CHOK1 cells

One herbicide (isoproturon), two fungicides (carbendazim and chlorothalonil) and etoposide (an effective antitumor agent used as a positive control), were tested for their ability to induce cytotoxic and genotoxic effects in Chinese Hamster Ovary (CHOK1) cells. Etoposide induced DNA damage detectable both by the alkaline Single Cell Gel Electrophoresis (SCGE) assay and the chromosomal aberration (CA) test in absence of noticeable cytotoxicity. With the SCGE assay, a clear induction of DNA damage was observed for chlorothalonil within a 0.2 to 1 microM concentration range. In the CA test, chlorothalonil gave also positive results, inducing mainly chromosome breaks. In contrast, no DNA damage was observed with the SCGE assay for carbendazim and isoproturon. In the CA test, carbendazim induced only numerical aberrations in the concentration range of 25 microM to 100 microM, and isoproturon did not induce any significant increase in CA. In conclusion, chlorothalonil appears genotoxic in proliferative CHOK1 cells, and as expected, the aneugenic compound, carbendazim, did not induce DNA strand breaks in the SCGE assay.     

Environmental noise as a cause of sleep disruption in an intermediate respiratory care unit

Our laboratory previously reported continuously monitored peak sound levels in several areas at Rhode Island Hospital. The number of sound peaks greater than 80 A-weighted decibels (dBA) was found to be high in the intensive and intermediate respiratory care unit (IRCU) areas, even at night. Environmental noise of this magnitude is potentially sleep-disruptive. Therefore, we hypothesized that nocturnal peak sound levels of > or = 80 dBA would be associated with an increase in EEG arousals from sleep in patients in the IRCU. Six patients underwent sleep monitoring while environmental peak sound levels were continuously recorded. Each 8-hour period (2200 to 0600 hours) was broken down into 30-minute segments. If there were 10 minutes or more of wakefulness in a segment, that segment was dropped from further analysis. Of the remaining 61 segments, there was a very strong correlation (r = 0.57, p = 0.0001) between the number of sound peaks of > or = 80 dBA and arousals from sleep. These 61 periods were then classified as quiet, moderately loud, and very loud based on the number of sound peaks (< or = 5, 6-15, and > 15, respectively). Analysis of variance revealed a significant difference between the number of arousals (p = 0.001) in quiet periods and that in very loud periods. We conclude that environmental noise may be an important cause of sleep disruption in the IRCU.     

Studies on the degradation of atrazine by bacterial communities enriched from various biotopes

Degradation of 14C-ring labeled atrazine (2-choloro-4-(ethylamino)-6-(isopropylamino)-s-triazine) by bacterial populations from soil, waters and activated sludges was investigated and compared with non-biological decomposition in sterile solutions. Within two weeks, 0.6% Cl-deethyl- and 0.1% Cl-deisopropylatrazine had been formed in sterile 0.02 M phosphate buffer, pH 7.2. In biodegradation studies, bacterial populations were enriched and incubated in media containing atrazine and high or low levels of nutrients. Nutrient supply had a strong effect on the fate of atrazine in bacterial cultures, whereas the origin of bacteria was of minor importance. In 31 of 33 mixed populations investigated, the herbicide was largely converted to unidentified compounds. Incubation with high levels of nutrients resulted in 17% to 57% of these compounds being constant after one and two weeks of incubation. In parallel experiments with low nutrient supply, the compounds were present in amounts of 7% to 57% after one week. The proportions of the unidentified compounds dropped within the second week of incubation, while atrazine reappeared correspondingly. The amounts of dealkylated metabolites generally did not exceed those of sterile solutions. The results indicate that atrazine is not degraded by bacteria but bound, thus simulating biodegradation. Evidence is presented that physicochemical decomposition of the herbicide is more significant than microbial degradation.     

Risk factors and prevention of thromboembolic risk in laparoscopy

PURPOSE: To investigate if retinol and carotenoids are present in the subretinal space following rhegmatogenous retinal detachment. METHODS: Blood and subretinal fluid were collected from patients at the time of surgical repair of retinal detachment. After removal of cellular contents in a specimen by centrifugation, the supernatant fraction was analyzed by liquid chromatography using a silica column eluted by 16% dioxane in hexane. Retinol and carotenoids were identified in the chromatograms based on their retention time and absorption spectrum. RESULTS: The retinol concentrations (mean+/-SD) in the serum and subretinal fluid were 305+/-144 and 166+/-96 ng/ml respectively. The 450 nm chromatogram had 7 peaks with the characteristic absorption spectrum of carotenoids. Peak 1 and 7 coincided with the retention time of beta-carotene (1.8 min) and lutein (10.8 min) respectively. The concentrations of beta-carotene and lutein in serum were 161+/-63 and 142+/-98 ng/ml respectively. There was very little beta-carotene in subretinal fluid (4.7+/-2.4 ng/ml). Lutein was the major carotenoid peak in subretinal fluid (41.4+/-14.1 ng/ml). The minor carotenoid peaks of serum were not observed in subretinal fluid. CONCLUSION: There is a substantial amount of retinol and lutein in subretinal fluid. The high proportion of lutein and very low amount of beta-carotene in the subretinal fluid support the occurrence of a highly selection transport mechanism of lutein from the blood to the retina.     

Immobilized liposome chromatography for studies of protein-membrane interactions and refolding of denatured bovine carbonic anhydrase

Seasonal variations of pesticide residues in surface waters and ground waters of the Imathia area of Central Mecedonia (N. Greece) were determined for the period from May 1996 to April 1997. The sampling cruises included eight sites in rivers Aliakmon, Loudias, Tripotamos, Arapitsa and Canal-66, seven water springs in the mountain Vermion, seven rainfall water collection stations and one hundred underground points. Solid-phase extraction disks followed by gas chromatographic techniques with flame thermionic detection, electron capture detection and mass-selective detection were used for the monitoring of various pesticides their transformation products in environmental waters. The most commonly encountered pesticides in underground waters, were alachlor, atrazine, desethylatrazine (DEA), metolachlor, molinate, propanil, simazine, carbofuran, diazinon and parathion methyl. The above compounds including propazine, trifluralin, malathion, parathion ethyl, lindane, alpha-benzene hexachloride (alpha-BHC), beta-BHC, 4,4'-DDE and heptachlor were determined in river waters. The higher concentrations in underground waters were measured during the period from May to August, 1996, following seasonal application and diminished significantly during the autumn and winter. Water pollution by triazine and chloroacetanilides was highest in the estuarine areas; showing that many of these compounds are transported significant distances from their application sites. The major inputs of atrazine, alachlor, simazine and metolachlor occurred in May and June just after their application. Atrazine, DEA, diazinon and metolachlor were also detected in spring waters at concentration levels below 0.006 microgram/l. Finally, atrazine, DEA, carbofuran, simazine, diazinon, parathion ethyl and parathion methyl were detected in rainfall water samples collected in the agricultural area of Imathia (central part of the plain).     

Enzyme immunoassay based survey of precipitation and surface water for the presence of atrazine, metolachlor and 2,4-D

The suitability of enzyme immunoassay (EIA) as a method of analysis for 2,4-D, atrazine and metolachlor contamination in water samples was determined by comparing EIA results to gas chromatography (GC) results. The comparison of EIA and GC results yielded a correlation coefficient of 0.92, 0.98 and 0.92 for 2,4-D, atrazine and metolachlor, respectively. EIA was used to monitor seasonal trends in the concentrations of 2,4-D, atrazine and metolachlor in surface water and precipitation throughout the province of Ontario, Canada. 2,4-D was detected in excess of 4 micrograms/L in urban creeks during the period of application. Concentrations of 43 and 9 micrograms/L of atrazine and metolachlor, respectively, were detected during the field application period in surface water samples from the Kintore Creek watershed. The levels of 2,4-D, atrazine and metolachlor detected exceeded the Canadian Water Quality Guidelines for the protection of fresh water aquatic life. Concentrations as high as 445 and 322 ng/L of atrazine and metolachlor, respectively, were detected in precipitation samples collected from 17 locations in Ontario during the herbicide application period. The EIA was shown to be qualitatively and quantitatively comparable to GC analysis.