Temperature modulates estrone degradation and biological effects of exposure in fathead minnows.

Environmental pollutants, including estrogens, are widespread in aquatic environments frequently as a result of treated wastewater effluent discharged. Exposure to estrogens has been correlated with disruption of the normal physiological and reproductive function in aquatic organisms, which could impair the sustainability of exposed populations. However, assessing the effects of estrogen exposure on individuals is complicated by the fact that rates of chemical uptake and environmental degradation are temperature dependent. Because annual temperature regimes often coincide with critical periods of biological activity, temperature-dependent changes in estrogen degradation efficacy during wastewater treatment could modulate biological effects. We examined the interactions between ambient water temperature and degradation of estrone (E1) during wastewater treatment. In addition, we exposed mature fathead minnows (Pimephales promelas) to three environmentally relevant concentrations of E1 at four different water temperatures (15°C, 18°C, 21°C, and 24°C) to reflect natural seasonal variation. E1 degradation occurred with and without the support of robust nitrification at all temperatures; however, the onset of E1 degradation was delayed at cooler water temperatures. In addition, we observed significant interactive effects between temperature and E1 exposure. Female morphometric endpoints were more susceptible to temperature-modulating effects while physiological endpoints were more strongly affected in males. Collectively, the data demonstrate that natural seasonal fluctuations in temperature are sufficient to affect E1 degradation during wastewater treatment and induce sex-dependent physiological and anatomical changes in exposed fish.

A novel N-aryl tyrosine activator of peroxisome proliferator-activated receptor-gamma reverses the diabetic phenotype of the Zucker diabetic fatty rat.

The discovery that peroxisome proliferator-activated receptor (PPAR)-gamma was the molecular target of the thiazolidinedione class of antidiabetic agents suggested a key role for PPAR-gamma in the regulation of carbohydrate and lipid metabolism. Through the use of high-throughput biochemical assays, GW1929, a novel N-aryl tyrosine activator of human PPAR-gamma, was identified. Chronic oral administration of GW1929 or troglitazone to Zucker diabetic fatty (ZDF) rats resulted in dose-dependent decreases in daily glucose, free fatty acid, and triglyceride exposure compared with pretreatment values, as well as significant decreases in glycosylated hemoglobin. Whole body insulin sensitivity, as determined by the euglycemic-hyperinsulinemic clamp technique, was significantly increased in treated animals. Comparison of the magnitude of glucose lowering as a function of serum drug concentrations showed that GW1929 was 2 orders of magnitude more potent than troglitazone in vivo. These data were consistent with the relative in vitro potencies of GW1929 and troglitazone. Isolated perfused pancreas studies performed at the end of the study confirmed that pancreata from vehicle-treated rats showed no increase in insulin secretion in response to a step change in glucose from 3 to 10 mmol/l. In contrast, pancreata from animals treated with GW1929 showed a first- and second-phase insulin secretion pattern. Consistent with the functional data from the perfusion experiments, animals treated with the PPAR-gamma agonist had more normal islet architecture with preserved insulin staining compared with vehicle-treated ZDF rats. This is the first demonstration of in vivo efficacy of a novel nonthiazolidinedione identified as a high-affinity ligand for human PPAR-gamma. The increased potency of GW1929 compared with troglitazone both in vitro and in vivo may translate into improved clinical efficacy when used as monotherapy in type 2 diabetic patients. In addition, the significant improvement in daily meal tolerance may impact cardiovascular risk factor management in these patients.

Role of mast cell chymase in the extracellular processing of big-endothelin-1 to endothelin-1 in the perfused rat lung.

Previous studies of endothelin-1 (ET) synthesis have shown that some cultured endothelial cells secrete an intermediate product, big-endothelin-1 (bigET), suggesting that the processing of secreted bigET to ET may be physiologically significant. In this study, two pertinent ET converting enzyme activities, mast cell chymase I (EC 3.4.21.39) and a phosphoramidon-sensitive, neutral metalloprotease, were identified in a rat lung particulate fraction. We perfused rat lungs with bigET and chymostatin or phosphoramidon to study the relevance of these two proteases to the processing of extracellular bigET in vivo. Addition of compound 48/80 (a compound which activates mast cells, causing degranulation and release of chymase) to the perfusion buffer greatly increased hydrolysis of exogenously added bigET to ET. ET formation was inhibited completely by 32 microM chymostatin, whereas inhibition by 50 microM phosphoramidon was incomplete and variable. Perfusate histamine levels were used to monitor the extent of mast cell degranulation, and inhibition of ET production by phosphoramidon was attributed to inhibition of degranulation, per se. There was a direct correlation between perfusate ET and histamine levels in both control and phosphoramidon-treated (but not chymostatin-treated) lungs. Our results suggest that chymase from lung mast cells is capable of physiologically relevant extracellular processing by bigET to ET in the perfused rat lung.

Influence of ferrous iron and ph on carbon tetrachloride degradation by Methanosarcina thermophila.

The influence of environmental conditions on the biological transformation of a contaminant must be well understood to optimize remediation processes. One factor that impacts the biological transformation of carbon tetrachloride (CT) is elemental iron (Fe0). Previous research has shown that Fe0 increases the methanogenic CT degradation rate by providing H2 for cell growth and dechlorination. As Fe0 oxidizes it also increases the pH and Fe2+ levels, which may also impact the biological transformation of CT. Experiments were performed with Methanosarcina thermophila to investigate the influence of these factors on CT degradation. The transformation of CT and CF was greatly influenced by pH, with the rate of CT and CF degradation increasing with increasing pH. After 6 h, > 90% of the CT had been degraded in the treatments containing cells at a pH of 8.5, whereas only about 51% of the CT had been degraded in similar treatments at a pH of 5.5. Fe2+ did not significantly influence the degradation of CT; however, 60% less CF was formed in systems containing cells+Fe2+ than in systems containing cells only. In addition. Fe2+ promoted rapid transformation of CF when added to treatments containing cells. The product distribution after 9 days in all systems containing cells was very similar, with 98.04 +/- 5.46% (two-sided 95% confidence interval) of the originally fed CT present as soluble products. These results show that pH and Fe2+ influence the degradation of CT and CF, although transiently. Because the residence time of contaminants in Fe0 barriers varies with the thickness of the barrier, it is likely that this influence will be important for some flow-through systems. This implies that a combined Fe0/organism remediation system may have previously unrealized advantages (due to pH and Fe2+ changes).

A novel in situ technology for the treatment of nitrate contaminated groundwater.

A novel in situ membrane technology was developed to remove nitrate (NO3-) from groundwater. Membrane-fed hydrogen gas (H2) was used as an electron donor to stimulate denitrification. A flow-through reactor fit with six hollow-fiber membranes (surface area = 93 cm2) was designed to simulate groundwater flowing through an aquifer with a velocity of 0.3 m/day. This membrane technology supported excellent NO3- and nitrite (NO2-) removal once H2 and carbon limitations were corrected. The membrane module achieved a maximum H2 flux of 1.79 x 10(-2) mg H2/m2 s, which was sufficient to completely remove 16.4 mg/L NO3(-)-N from a synthetic groundwater with no NO2- accumulation. In addition, this model in situ treatment process produced a high quality water containing <0.5 mg/L total organic carbon.

Passive dissolution of hydrogen gas into groundwater using hollow-fiber membranes.

A new hollow-fiber membrane remediation system has recently been developed to passively supply groundwater with dissolved hydrogen (H2) to stimulate the biodegradation of chlorinated solvents. Understanding the mass transfer behavior of membranes under conditions of creeping flow is critical for the design of such systems. Therefore, the objectives of this research were to evaluate the gas transfer behavior of hollow-fiber membranes under conditions typical of groundwater flow and to assess the effect of membrane configuration on gas transfer performance. Membrane gas transfer was evaluated using laboratory-scale glass columns operated at low flow velocities (8.6-12,973 cm/d). H2 was supplied to the inside of the membrane fibers while water flowed on the outside and normal to the fibers (i.e. cross-flow). Membrane configuration (single fiber and fabric) and membrane spacing for the fabric modules did not affect gas transfer performance. Therefore, the results from all of the experiments were combined to obtain the following dimensionless Sherwood number (Sh) correlation expressed as a function of Reynolds number (Re) and Schmidt number (Sc): Sh = 0.824Re(0.39)Sc(0.33) (0.0004

Evaluation of polyethylene hollow-fiber membranes for hydrogen delivery to support reductive dechlorination in a soil column.

Engineered systems are often needed to supply an electron donor, such as hydrogen (H(2)), to the subsurface to stimulate the biological dehalogenation of perchloroethene (PCE) to ethene. A column study was performed to evaluate the ability of gas permeable hollow-fiber membranes to supply H(2) directly to PCE-contaminated groundwater to facilitate bioremediation. Two glass columns were packed with soil obtained from a trichloroethene-contaminated site at Cape Canaveral, Florida, and were fed a minimal medium spiked with PCE (7 microM) for 391 days. The columns were operated in parallel, with one column receiving H(2) via polyethylene hollow-fiber membranes (lumen H(2) pressure of approximately 1atm) and a control column receiving no H(2). PCE was initially dechlorinated at a similar rate and to a similar extent in both columns, likely due to the presence of soil organic matter that was able to support dechlorination. After 265 days of operation, dechlorination performance declined in the control column and the benefits of membrane-supplied H(2) became evident. Although the membrane-supplied H(2) effectively stimulated PCE dechlorination at the end of the experiment (days 359-391), the system was inefficient in that only 5% of the supplied H(2) was used for dechlorination. Most of the remainder was used to support methanogenesis (94%). Despite the dominance of methanogens, nearly complete dechlorination of PCE to ethene was observed in the H(2)-fed column. In addition to the inefficient use of H(2), operational problems included excessive foulant accumulation on the outside of the membrane fibers and water condensation inside the fibers. Use of alternative membrane materials and changes to the operating approach (e.g. pulsing or supplying H(2) at low partial pressures) may help to overcome these problems so that this technology can provide effective and stable remediation of aquifers contaminated with chlorinated ethenes.

Membrane gas transfer under conditions of creeping flow: modeling gas composition effects.

A computational model was developed to predict gas transfer and gas composition changes in membrane modules designed for addition of gases to groundwater. The model was verified using pilot-scale gas transfer experiments. The modeling and experimental results suggest that back diffusion of dissolved gases into the membrane has a significant effect on gas transfer via hollow-fiber membrane. In the experimental study, N(2) back-diffusion reduced the partial pressure of O(2) within the membrane and decreased the concentration gradient for gas transfer. The model was able to simulate both the dynamic and steady-state gas transfer behavior of the membranes under a variety of operating conditions. This model can be used to estimate gas transfer as a function of different membrane module design and operating conditions.

Survival of indicator organisms during enrichment on tetrachloroethene.

A laboratory study was performed as the basis for a full-scale bioaugmentation project at a site contaminated with chlorinated ethenes. The objectives of this study were to 1) develop a protocol to enrich for a tetrachloroethene (PCE)-dechlorinating culture from waste activated sludge and anaerobic digester biosolids and 2) monitor the survival of fecal coliform bacteria and bacteriophage, which model enteric viruses, during the enrichment process. A culture was enriched in 8 days with the ability to degrade 6-microM PCE to cis-dichloroethene. Using the enrichment protocol in two identical experiments, significant inactivation of fecal coliform bacteria (2 log) and somatic coliphage (0.33 log) was observed in one of the experiments; no inactivation occurred in the second experiment. The number of F-specific coliphage decreased in both experiments (0.87 and 1.26 log inactivation). Despite the decrease in some of the coliform and bacteriophage numbers, the quantity of organisms and phage particles present after enrichment was still high (approximately 7.5 x 10(5) most probable number/L, 6.9 x 10(6) plaque-forming units (PFU)/L, and 3.3 x 10(5) PFU/L, for fecal coliform bacteria, somatic coliphage, and F-specific coliphage, respectively). This may be cause for concern, depending on the current and future groundwater use at or near a site undergoing bioaugmentation with cultures derived from waste activated sludge and anaerobic digester biosolids.

Chronic Acromioclavicular Joint Pain.

In brief Chronic pain at the acromioclavicular (AC) joint can suggest several diagnoses. When evaluating a patient's pain and range-of-motion deficits, remember that an AC joint can be the sole source of discomfort. The physical exam can help rule out impingement syndrome, rotator cuff tear, scapular winging, and systemic disorders; radiographs can help exclude other pathologies. Most patients respond to conservative treatment: anti-inflammatory medications, ice massage, and activity modification. However, pain that persists 6 months or longer may warrant surgery.

The effect of thermal hydrolysis pretreatment on the anaerobic degradation of nonylphenol and short-chain nonylphenol ethoxylates in digested biosolids.

The presence of micropollutants can be a concern for land application of biosolids. Of particular interest are nonylphenol diethoxylate (NP(2)EO), nonylphenol monoethoxylate (NP(1)EO), and nonylphenol (NP), collectively referred to as NPE, which accumulate in anaerobically digested biosolids and are subject to regulation based on the environmental risks associated with them. Because biosolids are a valuable nutrient resource, it is essential that we understand how various treatment processes impact the fate of NPE in biosolids. Thermal hydrolysis (TH) coupled with mesophilic anaerobic digestion (MAD) is an advanced digestion process that destroys pathogens in biosolids and increases methane yields and volatile solids destruction. We investigated the impact of thermal hydrolysis pretreatment on the subsequent biodegradation of NPE in digested biosolids. Biosolids were treated with TH, anaerobic digestion, and aerobic digestion in laboratory-scale reactors, and NPE were analyzed in the influent and effluent of the digesters. NP(2)EO and NP(1)EO have been observed to degrade to the more estrogenic NP under anaerobic conditions; therefore, changes in the ratio of NP:NPE were of interest. The increase in NP:NPE following MAD was 56%; the average increase of this ratio in four sets of TH-MAD samples, however, was only 24.6 ± 3.1%. In addition, TH experiments performed in pure water verified that, during TH, the high temperature and pressure alone did not directly destroy NPE; TH experiments with NP added to sludge also showed that NP was not destroyed by the high temperature and pressure of TH when in a more complex sludge matrix. The post-aerobic digestion phases removed NPE, regardless of whether TH pretreatment occurred. This research indicates that changes in biosolids processing can have impacts beyond just gas production and solids destruction.

Selection criteria for knee arthroscopy in the osteoarthritic patient.

In the current literature concerning arthroscopy in the osteoarthritic patient, there are few well-controlled studies with long-term follow-up that establish selection criteria. The effectiveness of abrasion arthroplasty has not been proved in prospective studies. Prospective factors that are associated with a better outcome include normal limb alignment, a history of mechanical symptoms, minimal roentgenographic degeneration, and a short duration of symptoms. Variables associated with poor outcomes include varus or valgus malalignment, loading symptoms, severe roentgenographic degeneration, previous surgeries, and chronic symptoms. Advanced age, per se, is not a contraindication to arthroscopy.

Cardiovascular effects of bromocriptine and lergotrile in renal and spontaneously hypertensive rats.

Cardiovascular effects of the dopamine receptor agonists, bromocriptine and lergotrile, were examined in renal hypertensive rats (RHR), spontaneously hypertensive rats (SHR) and in normotensive rats (NTR). In SHR, bromocriptine at 0.3 and 1.0 mg/kg i.p. and lergotrile at 0.3 mg/kg i.p. produced significant decreases in blood pressure and heart rate and the effects were prevented by haloperidol pretreatment. These results are consistent with the hypothesis that bromocriptine- and lergotrile-induced cardiovascular effects are due to a reduction in sympathetic tone via activation of neuronal dopamine receptors. In contrast to SHR, bromocriptine as well as lergotrile, at doses of 0.3 mg/kg i.p., were ineffective in RHR. Only at the 1 mg/kg i.p. dose, both the agents reduced blood pressure in RHR, but increased heart rate and only the effects of bromocriptine were antagonized by haloperidol. The magnitude and the duration of the hypotensive effect produced by both the agents were smaller in RHR than in SHR. The ganglion blocking agent, chlorisondamine, reduced blood pressure equally in RHR and SHR, but not in NTR, indicating a role for the sympathetic nervous system in the maintenance of high blood pressure in both SHR and RHR. It is further suggested that neuronal dopamine receptors that mediate reduction in resting sympathetic tone are less sensitive in RHR as compared to SHR.

Removal of the instrument Makar shoulder staple.

When confronted with the challenge of hardware removal during revision shoulder stabilization procedures, specialized instrumentation such as the Instrument Makar staple driver/extractor may become necessary. The Synthes DHS/DCS coupler screw may be more readily available, and can effectively substitute for the Instrument Makar staple driver/extractor.

Intrinsic sympathomimetic activity of labetalol.

In intact cats, cumulative doses (0.1-10 mg/kg i.v.) of labetalol produced dose-dependent decreases in heart rate and arterial blood pressure and dose-dependently reduced i.v. phenylephrine induced pressor responses. In spinal cats devoid of resting sympathetic tone, labetalol (1 mg/kg i.v.) produced a sustained elevation of heart rate and a transient fall in arterial blood pressure. In reserpine-pretreated, adrenalectomized cats, labetalol produced quantitatively the same effects as in spinal cats, indicating that the cardiovascular effects observed in cats with no resting sympathetic tone are due to a direct action of labetalol rather than via catecholamine release. The elevated heart rate due to labetalol in spinal cats was reduced by subsequent administration of the beta-adrenergic receptor antagonist, propranolol. Further, pretreatment with propranolol prevented the tachycardic and depressor effects of labetalol in spinal cats. In a separate group of spinal cats, labetalol administered in cumulative doses of up to 1 mg/kg i.v., produced graded increases in heart rate and also dose dependently reduced i.v. isoproterenol-induced tachycardic responses. Pindolol, a beta-adrenergic receptor antagonist with partial beta-agonist activity, produced similar effects in spinal cats at cumulative doses of 1-30 micrograms/kg. These results indicate that the alpha- and beta-adrenergic receptor antagonist, labetalol possesses partial beta-adrenergic receptor agonist activity. This intrinsic sympathomimetic action of labetalol appears to be more sustained on cardiac than on vascular beta-adrenergic receptors.

Effects of various environmental conditions on the transformation of chlorinated solvents by Methanosarcina thermophila cell exudates.

Several microbiologically produced biomolecules have been shown to degrade chlorinated contaminants found in groundwater systems. It was discovered that the cell-free exudates of the methanogen Methanosarcina thermophila were capable of carbon tetrachloride (CT) and chloroform (CF) degradation. Characterization of the exudates suggested that the active agents were porphorinogen-type molecules, possibly containing zinc. This research was performed to determine if the exudates from M. thermophila could be used for remediation purposes. The cell exudates were found to be capable of degrading CT, CF, tetrachloroethene, trichloroethene, and 1,1,1-trichloroethane. CT degradation was used to gauge exudate activity under a variety of conditions that would be encountered in the environment. The cell exudates were active when incubated in two types of soil matrices and at temperatures ranging from 4 to 23 degrees C. Over a 35-day period approximately 10.2 micromoles of CT were degraded by M. thermophila exudates. To test the hypothesis that the exudates contained either a zinc porphorinogen or a quinone, experiments were performed with zinc 5,10,15,20-tetra (4-pyridyl)-21 H, 23 H-porphine tetrakis, protoporphyrin IX zinc, and juglone. The two zinc porphyrins were capable of mediating CT degradation at rates comparable to those observed with the M. thermophila exudates; however, juglone was only capable of very slow CT transformation. The electron-transfer activity of the M. thermophila cell exudates was therefore more consistent with the activity of porphorinogens rather than quinones. Finally, in two enrichment cultures established from aquifer material and marine sediment, the possibility of excreted agents capable of degrading CT was evident.

Classification of phenoxybenzamine/prazosin-resistant contractions of rat spleen to norepinephrine by Schild analysis: similarities and differences to postsynaptic alpha-2 adrenoceptors.

The striking resistance of norepinephrine contractions of rat splenic strips to antagonism by the selective alpha-1 adrenoceptor antagonist prazosin was examined by Schild analysis. Prazosin was a simple competitive antagonist of contractions to phenylephrine indicating that this tissue possesses alpha-1 adrenoceptors. In contrast, the Schild regression for prazosin, with norepinephrine as the agonist, was nonlinear and had an overall slope of 0.24. These data indicated that norepinephrine activated a prazosin-resistant adrenoceptor in this tissue. As a working hypothesis, it was assumed that the prazosin-resistant receptor was an alpha-2 adrenoceptor; the concomitant addition of yohimbine, in concentrations below those required to block alpha-1 adrenoceptors, converted the atypical Schild regression for prazosin (norepinephrine as agonist) to a linear regression identical with that found for antagonism of phenylephrine responses. Selective alkylation of alpha-1 adrenoceptors with phenoxybenzamine (POB) eliminated responses to phenylephrine but not those to norepinephrine. After POB-alkylation and in the presence of a concentration of prazosin that was sufficient to produce a profound blockade of alpha-1 adrenoceptors, a response to norepinephrine remained. It was determined that the POB/prazosin-resistant response most likely was mediated by a homogeneous population of receptors by the finding that the Schild regressions for both yohimbine and idazoxan were identical with respect to slope and elevation when either norepinephrine or cobefrin were utilized as agonists, i.e., a difference in the regressions for these antagonists would be expected if the two agonists activated a heterogeneous receptor population.(ABSTRACT TRUNCATED AT 250 WORDS)

Investigation of cell exudates active in carbon tetrachloride and chloroform degradation.

Contamination of groundwater by chlorinated solvents such as carbon tetrachloride (CCl4) and chloroform (CHCl3) is a widespread problem. The cell exudates from the methanogen Methanosarcina thermophila are active in the degradation of CCl4 and CHCl3. This research was performed to characterize these exudates. Examination of the influence of pH indicated that activity was greater under alkaline conditions. Rapid CCl4 degradation occurred from 35-65 degrees C, with first-order degradation rate coefficients increasing as temperature increased. It was found that proteins were not responsible for CCl4 degradation. The active agents in the cell exudates were <10 kDa in size, with degradation activity present in both 1-10 kDa and <1 kDa size ranges. Upon purification of the <10 kDa size range of the cell exudates on a C(18) chromatography column, 17 fractions (out of 100) degraded >50% of the added CCl4 in 8 h. These 17 fractions were pooled into three samples based on their elution time from the C(18) column. One of these pooled samples contained elevated levels of cobalt, zinc, and iron, at 2, 3, and 13 times the levels measured in similarly fractionated and pooled samples of medium, respectively. The UV-visible spectrum of this pooled sample had an absorption maximum at 560-580 nm, which is similar to the absorption maxima of heme (approximately 550 and 575 nm). The two other pooled samples contained elevated levels of zinc at 11 and 22 times the concentration measured in similarly fractionated and pooled samples of medium, respectively, and also contained very low levels of nickel, cobalt, and iron. This research suggests that the cell exudates from M. thermophila contain porphorinogen-type molecules capable of dechlorination, possibly excreted corrinoids, hemes, and zinc-containing molecules.

Clinical and functional outcome of anterior cruciate ligament reconstruction in the recreational athlete over the age of 35.

This study examined the functional, objective, and subjective outcome of anterior cruciate ligament (ACL) reconstruction in recreational athletes > or = 35 years after a minimum of 2 years of follow-up. Patients > or = 35 years who underwent ACL reconstruction by a single surgeon were identified from our surgical database. Nineteen knees in 18 (62% follow-up) patients were available for review by an independent examiner. The patients underwent physical examination, radiographs, functional testing, isokinetic strength testing, and instrumented ligament arthrometer testing. All were seen at a minimum of 2 years of follow-up. The average age was 40 years. Five of 19 underwent reconstruction less than 1 month after injury, and the remainder underwent reconstruction for chronic injuries. All patients preoperatively had at least a grade 2 Lachman and a positive pivot shift noted on physical examination. After a minimum of 2 years of follow-up, 17 of 18 patients had a stable knee on objective testing, including a negative Lachman and pivot shift. Seventeen patients (94%) had < 3 mm side-to-side difference on maximum manual arthrometric testing. Only one patient had > 3 cm prone heel height difference, and all patients had > 125 degrees of flexion. Mean thigh circumference difference was 0.5 cm. Isokinetic testing demonstrated a mean 11%, 7%, and 4% quadriceps asymmetry at 60 degrees, 180 degrees, and 240 degrees/second, respectively. However, functional testing revealed only a mean 6% asymmetry on vertical jump, single leg hop, and timed 6 meter hop. Seventeen of 18 patients were satisfied with their results. The mean postoperative Lysholm Rating Scale score was 93. The mean Noyes Sports Activity Scale score was 86, improved from 31 preoperatively. Thirteen of 18 returned to their preinjury level of sports performance. These results indicate that ACL reconstruction in patients over the age of 35 has functional, objective, and subjective results comparable to those of a younger patient population.