First Report of Tobacco streak virus Infecting Kenaf (Hibiscus cannabinus) in India

The natural occurrence of Tobacco streak virus (TSV) in Hibiscus cannabinus was detected by enzyme-linked immunosorbent assay using an antiserum raised against TSV and reverse transcription polymerase chain reaction (PCR) using primers specific for the coat protein gene of the virus. Sequence analysis of the PCR products showed 99.6 and 99.5% of maximum identity at nucleotide and amino acid levels, respectively with TSV onion isolate from Kurnool (HM131490).This is the first report of the natural occurrence of TSV on kenaf in India.

Review article: herbal and dietary supplement hepatotoxicity

BACKGROUND

Herbal and dietary supplements are commonly used throughout the World. There is a tendency for underreporting their ingestion by patients and the magnitude of their use is underrecognised by Physicians. Herbal hepatotoxicity is not uncommonly encountered, but the precise incidence and manifestations have not been well characterised.

AIMS

To review the epidemiology, presentation and diagnosis of herbal hepatotoxicity. This review will mainly discuss single ingredients and complex mixtures of herbs marketed under a single label.

METHODS

A Medline search was undertaken to identify relevant literature using search terms including 'herbal', 'herbs', 'dietary supplement', 'liver injury', 'hepatitis' and 'hepatotoxicity'. Furthermore, we scanned the reference lists of the primary and review articles to identify publications not retrieved by electronic searches.

RESULTS

The incidence rates of herbal hepatotoxicity are largely unknown. The clinical presentation and severity can be highly variable, ranging from mild hepatitis to acute hepatic failure requiring transplantation. Scoring systems for the causality assessment of drug-induced liver injury may be helpful, but have not been validated for herbal hepatotoxicity. Hepatotoxicity features of commonly used herbal products, such as Ayurvedic and Chinese herbs, black cohosh, chaparral, germander, greater celandine, green tea, Herbalife, Hydroxycut, kava, pennyroyal, pyrrolizidine alkaloids, skullcap, and usnic acid, have been individually reviewed. Furthermore, clinically significant herb-drug interactions are also discussed.

CONCLUSIONS

A number of herbal medicinal products are associated with a spectrum of hepatotoxicity events. Advances in the understanding of the pathogenesis and the risks involved are needed to improve herbal medicine safety.

Standardization of terminology of virological response in the treatment of chronic hepatitis C: panel recommendations

The treatment paradigm for hepatitis C virus (HCV) infection is at a critical point in its evolution. The addition of a protease inhibitor to peginterferon plus ribavirin has become the new standard-of-care treatment for most patients. Data from clinical trials of new antivirals have been difficult to interpret and compare, partly because of heterogeneity in trial design, and partly because of inconsistencies in terminology used to define viral responses and the populations evaluated. Present definitions of viral responses for treatment with peginterferon and ribavirin are insufficient for novel treatment paradigms. Further, categorization of prior patient treatment experience in clinical trials, particularly of nonresponders to prior therapy, is inconsistent. Existing terms and definitions must be updated, standardized and/or redefined for easier interpretation of data and effective communication among clinicians. A panel of experts in HCV infection treatment met on 3 December 2009. Goals of the panel were to evaluate terms and definitions used traditionally in treatment with peginterferon and ribavirin, to refine and clarify definitions of existing terms that have varying meanings and to propose new terms and definitions appropriate for novel treatment paradigms emerging with development of new agents. A number of recommendations were accepted unanimously by the panel. Adoption of these terms would improve communication among investigators, enhance comparability among clinical trials, facilitate development of therapeutic guidelines and provide a standardized terminology for use in clinical practice.

Response to tenofovir monotherapy in chronic hepatitis B patients with prior suboptimal response to entecavir

Both entecavir (ETV) and tenofovir (TDF) are potent antiviral agents for hepatitis B virus (HBV). Suboptimal response (SOR) following antiviral therapy is associated with an increased risk of subsequent treatment failure and viral resistance. It remains unclear whether switching to TDF is a reasonable approach in patients with SOR to ETV treatment. This study was aimed to determine how HBV patients with SOR to ETV respond to TDF monotherapy. Data of patients with SOR to ETV (failure to achieve >1 log(10) HBV-DNA reduction during the last 24 weeks of ETV treatment) who were switched to TDF monotherapy during 2005 and 2010 were reviewed. Treatment adherence was assessed by pill-count. Fourteen patients (2.9%) were identified from a total cohort of 482 ETV-treated patients. All 14 patients were Chinese and were infected with HBV genotype C (71%) or B (29%). Nine patients were men, and the median age was 41.5 years (19-64). Twelve were treatment naïve (one lamivudine- and one peginterferon-experienced patient); 85.7% were HBeAg positive. The median baseline HBV-DNA was 7.55 (5.30-9.40) log(10) copies/mL, and 57% had abnormal serum alanine aminotransferase (ALT) levels. Precore and/or basal core promoter mutations were detected in four patients, whereas no genotypic resistance was detected at baseline and before switching to TDF. The median duration of ETV treatment was 64.5 (26-126) weeks. The median HBV-DNA at the time of switching to TDF was 3.69 (3.00-4.90) log(10) copies/mL. The median HBV-DNA reduction from baseline and during the last 6-month observation period prior to switching to TDF was 4.04 (0.51-6.06) log(10) and 0.43 (-0.09-1.13) log(10) copies/mL, respectively. After the switching to TDF, all 14 patients (100%) achieved undetectable HBV-DNA and ALT normalization within a median duration of 30 weeks. In 12 patients who were HBeAg positive, HBeAg seroconversion was observed in two patients after TDF treatment of 75- and 84-weeks duration. There was no virological breakthrough observed after switching to TDF with a median follow-up period of 50 (24-160) weeks. TDF treatment was safe and well tolerated. In conclusion, suboptimal response to ETV is rare (approximately 3%). TDF monotherapy is safe and very effective in the management of HBV patients with SOR to ETV.

Waitlist survival of patients with primary sclerosing cholangitis in the model for end-stage liver disease era

The ability of the Model for End-Stage Liver Disease (MELD) score to capture the urgency of transplantation may not be generalizable to patients with primary sclerosing cholangitis (PSC) because these patients face unique risks of death or removal from the liver transplant waitlist due to disease-specific complications (eg, repeated bouts of bacterial cholangitis and cholangiocarcinoma). We constructed Cox regression models to determine whether disease-based differences exist in waitlist mortality before liver transplantation. We compared the times to death or withdrawal from the waitlist due to clinical deterioration among patients with or without PSC in the United States after the implementation of the MELD allocation score. Over an 8-year period, 14,073 non-PSC patients (20.5%) and 432 PSC patients (13.6%) died or were removed (P < 0.0001). The adjusted hazard ratio (HR) for PSC was 0.72 [95% confidence interval (CI) = 0.66-0.79], which indicated that these patients had a lower time-dependent risk of death or removal from the waitlist in comparison with patients without PSC. This difference was explained in part by the groups' different probabilities of portal hypertension complications at listing because adjustments for these intermediate endpoints moved the HR closer to the null (0.84, 95% CI = 0.74-0.97). In comparison with patients with other forms of end-stage liver disease, patients with PSC are less likely to die or be removed from the waitlist because of clinical deterioration; therefore, the prevailing practice in some centers and regions of preemptively referring PSC patients for living donor transplantation or exception points should be reconsidered.

Clinical features and natural history of hepatocellular adenomas: the impact of obesity

BACKGROUND

Hepatocellular adenoma is a benign tumour associated with bleeding and malignant transformation. Obesity has been linked to hepatic tumourigenesis.

AIM

To evaluate the presentation of hepatocellular adenoma in obesity, and the impact of obesity on the clinical course.

METHODS

Records of 60 consecutive patients (between 2005 and 2010) with a diagnosis of hepatocellular adenoma from a single tertiary centre were analysed.

RESULTS

Fifty six of 60 patients were women, median age was 36years, 75% had history of contraceptive use, 18% were overweight and 55% were obese (BMI ≥30kg/m(2) ). Majority (63%) were asymptomatic; seven patients presented with bleeding. Single (28%) and multiple adenomas (72%) were encountered; size ranged from 1 to 19.7cm. Obesity was more often associated with multiple adenomas (85% vs. 48%, P=0.005), bilobar distribution (67% vs. 33%, P=0.01), lower serum albumin (P=0.007) and co-morbidities of fatty liver (P=0.006), diabetes (P=0.003), hypertension (P=0.006) and dyslipidemia (P=0.03). During median follow-up of 2.6years, there were no instances of bleeding, malignant transformation or death. Thirty four patients underwent therapeutic intervention (17 surgical resection, nine transarterial embolization and eight both interventions sequentially). The rate of complete resection of adenoma(s) was significantly lower in obese patients (8% vs. 69%, P=0.004). In the 26 patients without intervention, tumour size progression was more frequently observed in obese patients (33% vs. 0%, P=0.05). Three of 15 obese patients (20%) lost ≥5% body weight and there was no progression in the liver lesions.

CONCLUSIONS

Obesity and features of metabolic syndrome were frequently observed in hepatocellular adenoma. Multiple and bilobar adenomas were more frequent in obese patients. Among patients who were conservatively managed, tumour progression was more often associated with obesity.

Synthesis of 3'-amino-3'-deoxyguanosine and 3'-amino-3'-deoxyxyloguanosine monophosphate HepDirect prodrugs from guanosine

The synthesis of 3'-amino-3'-deoxyguanosine and 3'-amino-3'-deoxyxyloguanosine monophosphate HepDirect prodrugs from guanosine is reported. Initial incorporation of N,N-dibenzylformamidino protection of the C2-amino of guanosine masked the reactivity of that group and simplified purification of subsequent analogues. The first key intermediate, 9-(2,5-bis-O-tert-butyldimethylsilyl-beta-D-ribofuranosyl)-2-N-(N,N-dibenzylformamidino)guanine (3a), was prepared in 60% yield after recycling of the undesired 3',5'-bis-O-protected byproduct (4a) by simple equilibration in methanol to a mixture of the two bis-O-protected compounds. Thus, protected, the 3'-position was manipulated to form the 3'-deoxyribo- or 3'-deoxyxylo-3'-azido derivatives (9 or 16, respectively). Further selective manipulations provided the cis-5'-monophosphate (3-chlorophenyl)-1,3-propanyl diester prodrugs (HepDirect prodrugs), 15 and 21. These HepDirect prodrugs were demonstrated to activate to their respective NTPs in rat hepatocytes.

Cowpea (Vigna unguiculata [L.] Walp.) genotypes response to multiple abiotic stresses

The carbon dioxide concentration [CO(2)], temperature and ultraviolet B radiation (UVB) are concomitant factors projected to change in the future environment, and their possible interactions are of significant interest to agriculture. The objectives of this study were to evaluate interactive effects of atmospheric [CO(2)], temperature, and UVB radiation on growth, physiology and reproduction of cowpea genotypes and to identify genotypic tolerance to multiple stressors. Six cowpea (Vigna unguiculata [L.] Walp.) genotypes differing in their sites of origin were grown in sunlit, controlled environment chambers. The treatments consisted of two levels each of atmospheric [CO(2)] (360 and 720 micromol mol(-1)), UVB [0 and 10 kJ m(-2)d(-1)) and temperatures [30/22 and 38/30 degrees C] from 8 days after emergence to maturity. The ameliorative effects of elevated [CO(2)] on increased UVB radiation and temperature effects were observed for most of the vegetative and photosynthetic traits but not for pollen production, pollen viability and yield attributes. The combined stress response index (C-TSRI) derived from vegetative (V-TSRI) and reproductive (R-TSRI) parameters revealed that the genotypes responded negatively with varying magnitude of responses to the stressors. Additionally, in response to multiple abiotic stresses, the vegetative traits diverged from that of reproductive traits, as deduced from the positive V-TSRI and negative R-TSRI observed in most of the genotypes and poor correlation between these two processes. The UVB in combination with increased temperature caused the greatest damage to cowpea vegetative growth and reproductive potential. The damaging effects of high temperature on seed yield was not ameliorated by elevated [CO(2)]. The identified tolerant genotypes and groups of plant attributes could be used to develop genotypes with multiple abiotic stress tolerance.

Fructose-1,6-bisphosphatase Inhibitors. 2. Design, synthesis, and structure-activity relationship of a series of phosphonic acid containing benzimidazoles that function as 5'-adenosinemonophosphate (AMP) mimics

Efforts to enhance the inhibitory potency of the initial purine series of fructose-1,6-bisphosphatase (FBPase) inhibitors led to the discovery of a series of benzimidazole analogues with human FBPase IC(50)s < 100 nM. Inhibitor 4.4 emerged as a lead compound based on its potent inhibition of human liver FBPase (IC(50) = 55 nM) and significant glucose lowering in normal fasted rats. Intravenous administration of 4.4 to Zucker diabetic fatty rats led to rapid and robust glucose lowering, thereby providing the first evidence that FBPase inhibitors could improve glycemia in animal models of type 2 diabetes.

Peginterferon alpha-2a (40 kDa) and ribavirin: comparable rates of sustained virological response in sub-sets of older and younger HCV genotype 1 patients

The average age of patients initiating therapy for HCV is increasing, with older patients exhibiting lower responses to therapy than younger patients. Identification of those older patients likely to respond needs to be addressed. Using data from 569 genotype-1 patients enrolled in two phase III studies (NV15801/NV15942) randomized to peginterferon alpha-2a (40 KDa) 180 microg/week plus ribavirin 1000/1200 mg/day for 48-weeks, we investigated factors associated with sustained virological response (SVR; undetectable HCV-RNA 24-weeks post-treatment) in patients >50 years. SVR rates among patients <or=50 was greater than those >50 years (52%vs 39%; P = 0.0073). Older patients with a rapid virological response (RVR; undetectable HCV-RNA at treatment week 4) or complete early virological response (cEVR; detectable HCV-RNA at week 4 but HCV-RNA <50 IU/mL at week-12) demonstrated high SVR rates (83% and 61% respectively). Older patients had lower cumulative peginterferon alpha-2a exposure and significantly lower cumulative ribavirin exposure (252 g vs 304 g in younger patients; P < 0.0001). Higher relapse rates were observed in older patients (41%vs 25%; P = 0.0042). Cumulative drug exposure and achievement of RVR or cEVR were significantly predictive of SVR by multiple logistic regression analysis in patients >50 years. Other baseline characteristics predictive of SVR in those >50 years of age were lower baseline HCV-RNA level (P = 0.0067), higher ALT-ratio (P = 0.0113) and absence of cirrhosis (P = 0.0482). Response rates were high among patients >50 years without cirrhosis who maintained adequate drug exposure and those achieving an RVR or cEVR. More frequent dose modifications of ribavirin in those >50 years likely contributed to the observed higher relapse rates.

Development of indices to predict phosphorus release from wetland soils

The U.S. Environmental Protection Agency created the Clean Water Action Plan to develop nutrient criteria for four water body types: lakes and reservoirs, rivers and streams, estuaries, and wetlands. Significant progress has been made in open water systems. However, only areas in and around the Florida Everglades have had numeric nutrient criteria set, due to the complexity, heterogeneity, and limited information available for wetlands. Our objective was to evaluate various soil tests to predict significant P release potential of soil in wetlands. A total of 630 surface soil samples (0-10 cm) were collected for this study from four southeastern states: Florida, Alabama, Georgia, and South Carolina. Soil samples were collected from the center of wetlands, the edge of the wetlands, and from adjacent uplands. The phosphorus saturation ratios (PSR), calculated using P, Fe, and Al molar concentrations from Mehlich 1 (M1-PSR), Mehlich 3 (M3-PSR), and oxalate (Ox-PSR) extractions and the amount of P extracted by different extractants were used to predict P loss potential from a soil. Total phosphorus (TP) concentration in wetland soils, estimated as the 75th percentile of the distribution of least impacted wetland soils as an example, was approximately 550 mg kg(-1). Based on this reference background condition, procedures for obtaining threshold values for P release to the surrounding water bodies were developed and threshold values calculated: M1-P = 24 mg kg(-1), M3-P = 44 mg kg(-1), Ox-PSR = 0.079, M1-PSR = 0.101, and M3-PSR = 0.067.

Inhibition of Aspergillus flavus colonization and aflatoxin (AfB1) in peanut by methyleugenol

Methyleugenol is naturally occurring substance in oils and fruits and in various foods as flavoring agent. Effect of this methyleugenol in inhibiting A. flavus colonization and aflatoxin production on peanut pods and kernels has been studied. Spray of methyleugenol (0.5%) on peanut pods and kernels checked the colonization of A. flavus and aflatoxin synthesis. This chemical can be used as both prophylactic or post infection spray on peanut pods before storage. It is the first report on the inhibition of A. flavus by methyleugenol on peanut.

Response of bahiagrass carbon assimilation and photosystem activity to below optimum temperatures

Photosynthesis and growth of tropical grasses are sensitive to cool season temperatures but information on the responsive mechanisms is limited in many species including bahiagrass (Paspalum notatum Flueggé). Therefore, an experiment was conducted in sunlit, controlled environment chambers to determine the effect of below optimum temperatures on leaf net photosynthesis (A) and chlorophyll fluorescence (F) and response to internal [CO₂] (C_i) and photosynthetic photon flux density (PPFD) of A and F of bahiagrass. Five day/night temperatures of 14/6, 18/10, 22/14, 26/18 and 30/22°C were imposed from 55 to 100 days after transplanting for plants grown initially for 55 days at 30/22°C. Leaf A and F were measured from 1000 to 1400 hours between -1 to 35 days after imposing temperature treatments. Leaf A-F/C_i and A-F/PPFD response curves were measured between 11 and 20 days after start of temperature treatments. After 35 days of treatment, the cold acclimation response of leaf A was assessed by lowering temperature in all treatments to 6°C and measuring A and F for a 3-day period. Repeated-measures analysis showed significant effects of time, temperature and time × temperature. The reduction of A on the first day of cold shock was 64, 37, 61, 64 and 81% in plants previously grown at 14, 18, 22, 26 and 30°C, respectively, which indicates acclimation at 18°C. Below optimum temperature significantly lowered CO₂-saturated net photosynthesis (A_sat), carboxylation efficiency (CE) and electron transport rate (ETR) derived from A-F/C_i curves. Below optimum temperature also lowered light-saturated photosynthesis (A_max), Rd and ETR derived from A-F/PPFD curves. The relationship between φ_CO2 and φ_PSII showed that bahiagrass A was more sensitive than electron transport at below optimum temperatures, which may be associated with increased CO₂ leakage and over-cycling of C₄ acid cycle. The leaf-level photosynthesis parameters and their response functions will also help to improve algorithms for simulating forage growth under variable temperature conditions.

Review article: the evaluation of solitary liver masses

BACKGROUND

The increasing use of imaging modalities has led to the detection of more liver masses. The differential diagnosis of a focal liver mass includes a host of benign as well as malignant conditions.

AIM

To provide a comprehensive review on the commonly encountered liver masses, and to help guide an approach to their evaluation and management.

METHODS

Pertinent literature that was identified through PubMed search and senior author's experience formed the basis of this review.

RESULTS

While most incidentally noted liver masses are benign, it may be difficult to differentiate them from those that are malignant. Furthermore, some benign lesions have malignant potential. Certain lesions such as focal nodular hyperplasia, haemangiomas and focal steatosis are often distinctly diagnosed by an imaging modality alone. The less frequently encountered hepatic adenomas are diagnosed radiologically in those with the appropriate clinical background and the absence of radiological features to suggest haemangioma or focal nodular hyperplasia.

CONCLUSIONS

A reasonable approach to the diagnosis, follow-up and management of liver masses is based on a rudimentary knowledge of their presentation, associated clinical and laboratory features, natural history and available treatment options. Most often, the so called 'incidentalomas' are benign and require patient reassurance.

Hepatocellular carcinoma in long-term sustained virological responders following antiviral combination therapy for chronic hepatitis C

Antiviral treatment results in a sustained virologic response (SVR) in 50-75% of patients with chronic hepatitis C. Long-term follow up studies have observed ongoing SVR in the overwhelming majority of them. Thus chronic hepatitis C is considered 'cured' if an SVR is achieved. Consequently, it is expected that in sustained virologic responders long-term complications of hepatatic C virus (HCV) related chronic liver disease including hepatocellular carcinoma are eliminated or have a decreased incidence. We report on five patients (three from Austria, two from USA) who developed hepatocellular carcinoma during follow up (3-6 years) after achieving SVR. During follow up and at diagnosis all were HCV-RNA neg. None of the patients had other liver diseases. One patient presented with bilateral adrenal metastasis, the remaining four with large hepatic tumours. Three patients were noncirrhotic at the start of treatment at the time of tumour diagnosis. Successful antiviral treatment in HCV patients does not prevent development of hepatocellular carcinoma even in non-cirrhotic livers. Long-term follow up of patients with SVR is mandatory and should include surveillance for hepatocellular carcinoma.

Assessing genotypic variability of cowpea (Vigna unguiculata [L.] Walp.) to current and projected ultraviolet-B radiation

The current and projected terrestrial ultraviolet-B (UV-B) radiation affects growth and reproductive potential of many crops. Cowpea (Vigna unguiculata [L.] Walp.), mostly grown in tropical and sub-tropical regions may already be experiencing critical doses of UV-B radiation due to a thinner ozone column in those regions. Better understanding of genotypic variability to UV-B radiation is a prerequisite in developing genotypes tolerant to current and projected changes in UV-B radiation. An experiment was conducted in sunlit, controlled environment chambers to evaluate the sensitivity of cowpea genotypes to a range of UV-B radiation levels. Six cowpea genotypes [Prima, California Blackeye (CB)-5, CB-27, CB-46, Mississippi Pinkeye (MPE) and UCR-193], representing origin of different geographical locations, were grown at 30/22 degrees C day/night temperature from seeding to maturity. Four biologically effective ultraviolet-B radiation treatments of 0 (control), 5, 10, and 15 kJ m(-2)d(-1) were imposed from eight days after emergence to maturity. Significant genotypic variability was observed for UV-B responsiveness of eighteen plant attributes measured. The magnitude of the sensitivity to UV-B radiation also varied among cowpea genotypes. Plants from all genotypes grown in elevated UV-B radiation were significantly shorter in stem and flower lengths and exhibited lower seed yields compared to the plants grown under control conditions. Most of the vegetative parameters, in general, showed a positive response to UV-B, whereas the reproductive parameters exhibited a negative response showing the importance of reproductive characters in determining tolerance of cultivars to UV-B radiation. However, all cultivars, except MPE, behaved negatively to UV-B when a combined response index was derived across parameters and UV-B levels. Based on the combined total stress response index (C-TSRI) calculated as sum of individual vegetative, physiological and reproductive component responses over the UV-B treatments, the genotypes were classified as tolerant (MPE), intermediate (CB-5, CB-46 and UCR-193) and sensitive (CB-27 and Prima) to UV-B radiation. The differences in sensitivity among the cowpea genotypes emphasize the need for selecting or developing genotypes with tolerance to current and projected UV-B radiation.

The response of benthic foraminifera to various pollution sources: a study from Nellore Coast, East Coast of India

A study of benthic foraminiferal species was carried out along Nellore Coast of South India. Analysis of surfacial sediment samples from the study area shows enrichment in heavy metals (Cr, Cu, Pb and Zn). The environment has become so lethal to foraminifera that minimal species number (4-7) can currently preserved in living condition in a depth less than 5-fth contour from coast. Samples from outfalls which receive only agricultural and aquacultural drainage water show heavy metal concentrations slightly higher to natural baseline levels, and yielding, living foraminifera (10-15). The frequent occurrence of deformed and abnormal specimens in Industrial outfalls, comparable to aquacultural and agricultural outlets reveal that (a) benthic foraminifera are more sensitive to industrial wastes containing heavy metals, (b) agricultural and aquacultural wastes do not significantly harm benthic foraminifera, and (c) morphological abnormalities of the foraminiferal tests depend upon the nature of the pollutant.

Hepatic steatosis in chronic hepatitis C: baseline host and viral characteristics and influence on response to therapy with peginterferon alpha-2a plus ribavirin

Hepatic steatosis is common in hepatitis C virus (HCV)-infected patients and may be associated with the metabolic syndrome. We studied steatosis in patients treated with peginterferonalpha-2a plus ribavirin. Forty-five of 207 patients (22%) had >5% hepatic steatosis at baseline. Significantly more patients with steatosis than without were HCV genotype 3 (51%vs 14%; P < 0.0001) had higher HCV-RNA (P = 0.0045), body weight (P = 0.0176), body mass index (BMI, P = 0.0352) and serum triglycerides (TG) (P = 0.0364), hypertriglyceridaemia (P = 0.0009), elevated blood pressure/history of hypertension (P = 0.0229) and lower cholesterol (P = 0.0009). Significant steatosis predictors were genotype 3 (OR 9.04, 95% CI 3.85-21.21, P < 0.0001), HCV-RNA (OR 2.96, 1.49-5.88, P = 0.0019) and triglycerides (OR 1.06, 1.02-1.11, P = 0.0071). In genotype 3 patients, HCV-RNA was the only significant predictor (OR 11.15, 2.60-47.81, P = 0.0012). In non-genotype 3 patients, hypertriglyceridaemia was the only significant predictor (OR 1.07, 1.02-1.12, P = 0.0041). 134 of 207 patients (65%) achieved an sustained virological response (SVR) with peginterferon alpha-2a plus ribavirin, similar to the overall response rate. In genotype 3 patients with an SVR, steatosis decreased from 48% to 13% (baseline to end-point). No change was seen in the steatosis rate in non-genotype 3 patients with an SVR. This large and comprehensive analysis of a large data base from a multinational trial further adds to the observations that chronic HCV is associated with hepatic steatosis in approximately a fifth of patients. Further, features of the metabolic syndrome are associated with hepatic steatosis in most of these patients. Steatosis is significantly more common in genotype 3 compared with other genotypes, and in these patients, an SVR is associated with steatosis clearance.

Pradefovir: a prodrug that targets adefovir to the liver for the treatment of hepatitis B

Adefovir dipivoxil, a marketed drug for the treatment of hepatitis B, is dosed at submaximally efficacious doses because of renal toxicity. In an effort to improve the therapeutic index of adefovir, 1-aryl-1,3-propanyl prodrugs were synthesized with the rationale that this selectively liver-activated prodrug class would enhance liver levels of the active metabolite adefovir diphosphate (ADV-DP) and/or decrease kidney exposure. The lead prodrug (14, MB06866, pradefovir), identified from a variety of in vitro and in vivo assays, exhibited good oral bioavailability (F = 42%, mesylate salt, rat) and rate of prodrug conversion to ADV-DP. Tissue distribution studies in the rat using radiolabeled materials showed that cyclic 1-aryl-1,3-propanyl prodrugs enhance the delivery of adefovir and its metabolites to the liver, with pradefovir exhibiting a 12-fold improvement in the liver/kidney ratio over adefovir dipivoxil.

Phosphorus sorbing materials: sorption dynamics and physicochemical characteristics

The effectiveness of various management practices to reduce phosphorus (P) loss from soil to water can potentially be improved by using by-product materials that have the capacity to sorb phosphorus. This study evaluated the P sorption and desorption potential, and the physicochemical characteristics of various phosphorus sorbing materials. Twelve materials were selected and P sorption potentials ranged between 66 and 990 mg kg(-1). Iron, and calcium drinking water treatment residuals (DWTRs), a magnesium fertilizer by-product, aluminum, and humate materials all removed substantial amounts of P from solution and desorbed little. Humate had the highest maximum P sorption capacity (S(max)). Materials which had a low equilibrium P concentration (EPC(0)) and a high S(max) included aluminum and humate by-products. In a kinetic study, the Fe-DWTR, Ca-DWTR, aluminum, and magnesium by-product materials all removed P (to relatively low levels) from solution within 4 h. Phosphorus fractionation suggests that most materials contained little or no P that was readily available to water. Sand materials contained the greatest P fraction associated with fulvic and humic acids. In general, materials (not Ca-DWTR) and magnesium by-product were composed of sand-sized particles. There were no relationships between particle size distributions and P sorption in materials other than sands. The Ca- and Fe-DWTR, and magnesium by-product also contained plant nutrients and thus, may be desirable as soil amendments after being used to sorb P. Further, using Ca-DWTRs and Fe-DWTRs as soil amendments may also increase soil cation exchange and water holding capacity.

Hypercoagulation and thrombophilia in liver disease

A complex balance exists between endogenous procoagulants and the anticoagulant system in liver disease patients. Hypercoagulable events occur in cirrhosis patients despite the well-known bleeding diathesis of liver disease. These events may be clinically evident, such as in portal vein thrombosis or pulmonary embolism, but these conditions may also be a silent contributor to certain disease states, such as portopulmonary hypertension or parenchymal extinction with liver atrophy as well as thrombosis of extracorporeal circuits in dialysis or liver assist devices. Moreover, liver disease-related hypercoagulability may contribute to vascular disease in the increasingly common condition of non-alcoholic fatty liver disease. Despite the incidence of these problems, there are few widely accessible and practical laboratory tests to evaluate the risk of a hypercoagulable event in cirrhosis patients. Furthermore, there is little research on the use of commonly accepted anticoagulants in patients with liver disease. This article is a result of an international symposium on coagulation disorders in liver disease and addresses several areas of specific interest in hypercoagulation in liver disease. Critical areas lacking clinical information are highlighted and future areas of research interest are defined with an aim to foster clinical research in this field.

Soil biogeochemical characteristics influenced by alum application in a municipal wastewater treatment wetland

Constructed treatment wetlands are a relatively low-cost alternative used for tertiary treatment of wastewater. Phosphorus (P) removal capacity of these wetlands may decline, however, as P is released from the accrued organic soils. Little research has been done on methods to restore the treatment capacity of aging constructed wetlands. One possibility is the seasonal addition of alum during periods of low productivity and nutrient removal. Our 3-mo mesocosm study investigated the effectiveness of alum in immobilizing P during periods of reduced treatment efficiency, as well as the effects on soil biogeochemistry. Eighteen mesocosms were established, triplicate experimental and control units for Typha sp., Schoenoplectus californicus, and submerged aquatic vegetation (SAV) (Najas guadalupensis dominated). Alum was slowly dripped to the water column of the experimental units at a rate of 0.91 g Al m(-2) d(-1) and water quality parameters were monitored. Soil cores were collected at experiment initiation and completion and sectioned into 0- to 5- and 5- to 10-cm intervals for characterization. The alum floc remained in the 0- to 5-cm surface soil, however, soil pH and microbial parameters were impacted throughout the upper 10 cm with the lowest pH found in the Typha treatment. Plant type did not impact most biogeochemical parameters; however, data were more variable in the SAV mesocosms. Amorphous Al was greater in the surface soil of alum-treated mesocosms, inversely correlated with soil pH and microbial biomass P in both soil layers. Microbial activity was also suppressed in the surface soil of alum-treated mesocosms. This research suggests alum may significantly affect the biogeochemistry of treatment wetlands and needs further investigation.

Cost-effectiveness of suppressing hepatitis B virus DNA in immune tolerant patients to prevent hepatocellular carcinoma and cirrhosis

BACKGROUND

For patients with hepatitis B virus (HBV) infection in the immune tolerant phase, the current standard of care is to not offer treatment. However, the recent Risk Evaluation of the Viral Load Elevation and Associated Liver Disease/Cancer-In study results show a striking relationship between high HBV DNA levels and risk for hepatocellular carcinoma and cirrhosis.

AIM

In a cost effectiveness analysis, to assess whether immune tolerant patients with high HBV DNA levels should undergo treatment.

METHODS

We created a lifetime Markov model to evaluate the cost-effectiveness of two strategies for immune tolerant hepatitis B: (i) HBV DNA suppression with lamivudine, (ii) no treatment. Patients cycled between the following health states: viral suppression, ongoing viremia, seroconversion, hepatocellular carcinoma, cirrhosis and death.

RESULTS

Compared with the no treatment strategy, lamivudine therapy was more expensive but more cost-effective with an additional cost of $5784 and $12 584 per quality adjusted life year gained in males and females, respectively. Treatment resulted in a gain in life expectancy and a decrease in lifetime risk of hepatocellular carcinoma and cirrhosis.

CONCLUSIONS

Suppressing HBV DNA to prevent hepatocellular carcinoma and cirrhosis in immune tolerant patients is very cost-effective, and treatment of these patients may be considered. Future prospective clinical trials will need to be undertaken to confirm our findings.

Liver-Targeted Prodrugs of 2‘-C-Methyladenosine for Therapy of Hepatitis C Virus Infection

2'-C-Methyladenosine exhibits impressive inhibitory activity in the cell-based hepatitis C virus (HCV) subgenomic replicon assay, by virtue of intracellular conversion to the corresponding nucleoside triphosphate (NTP) and inhibition of NS5B RNA-dependent RNA polymerase (RdRp). However, rapid degradation by adenosine deaminase (ADA) limits its overall therapeutic potential. To reduce ADA-mediated deamination, we prepared cyclic 1-aryl-1,3-propanyl prodrugs of the corresponding nucleoside monophosphate (NMP), anticipating cytochrome P450 3A-mediated oxidative cleavage to the NMP in hepatocytes. Lead compounds identified in a primary rat hepatocyte screen were shown to result in liver levels of NTP predictive of efficacy after intravenous dosing to rats. The oral bioavailability of the initial lead was below 5%; therefore, additional analogues were synthesized and screened for liver NTP levels after oral administration to rats. Addition of a 2',3'-carbonate prodrug moiety proved to be a successful strategy, and the 1-(4-pyridyl)-1,3-propanyl prodrug containing a 2',3'-carbonate moiety displayed oral bioavailability of 39%.

Simultaneous liver-kidney transplantation: evaluation to decision making

Questions about appropriate allocation of simultaneous liver and kidney transplants (SLK) are being asked because kidney dysfunction in the context of liver failure enhances access to deceased donor organs. There is specific concern that some patients who undergo combined liver and kidney transplantation may have reversible renal failure. There is also concern that liver transplants are placed prematurely in those with end-stage renal disease. Thus to assure allocation of transplants only to those truly in need, the transplant community met in March 2006 to review post-MELD (model for end-stage liver disease) data on the impact of renal function on liver waitlist and transplant outcomes and the results of SLK.

Recent changes in soil total phosphorus in the Everglades: Water Conservation Area 3

We assessed recent changes in the distribution of soil total phosphorus (TP) in Water Conservation Area 3 (WCA-3) of the Everglades. Soil cores were collected in 1992 and 2003 at 176 sites. To reflect hydrologic boundaries within the system, WCA-3 was divided into three zones (3AN, 3AS, and 3B). Total P was mapped on both a mass (TPm) and a volumetric basis (TPv) to determine if spatial distributions varied depending on the choice of units. Interpolated maps for both years showed that the highest levels of TPm were located in 3AN and in boundary areas of all zones that received surface water inputs of P from canals. Increases in TPm were greatest in central 3AN in an area adjacent to the Miami Canal that received inputs from a water control structure. Interpolated maps for TPv illustrated that a hotspot present in 1992 had disappeared by 2003. The highest levels of TPv in 2003 were located in northwestern 3AN, a region of WCA-3 that has been chronically overdrained and burned in 1999. From 1992 to 2003, increases in TPm were observed for 53% of the area of WCA-3, while only 16% of WCA-3 exhibited increases in TPv. In 1992, approximately 21% of WCA-3 had TPm concentrations in the 0-10 cm layer >500 mg kg(-1), indicating P enrichment beyond historic levels. Eleven years later, 30% of the area of WCA-3 had TPm >500 mg kg(-1). This indicated that during this period, the area of WCA-3 with enriched TPm concentrations increased about one % year(-1).

Increased soil stable nitrogen isotopic ratio following phosphorus enrichment: historical patterns and tests of two hypotheses in a phosphorus-limited wetland

We used a P enrichment gradient in the Everglades to investigate patterns of the stable N isotopic ratio (delta(15)N) in peat profiles as an indicator of historic eutrophication of this wetland. We also tested two hypotheses to explain the effects of P on increased delta(15)N of organic matter including: (1) increased N mineralization/N loss, and (2) reduced isotopic discrimination during macrophyte N uptake. Spatial patterns of delta(15)N in surface litter and soil (0-10 cm) mimic those of the aboveground macrophytes (Typha domingensis Pers. and Cladium jamaicense Crantz). Peat profiles also show increased delta(15)N in the peat accumulated in areas near the historic P discharges since the early 1960s. The increased delta(15)N of bulk peat correlated well with both measured increases in soil total P and the historical beginning of nutrient discharges into this wetland. In 15-day bottle incubations of soil, added P had no effect on the delta(15)N of NH (4) (+) and significantly increased the delta(15)N of water-extractable organic N. Measurements of surface soils collected during a field mesocosm experiment also revealed no significant effect of P on delta(15)N even after 5 years of P addition. In contrast, delta(15)N of leaf and root tissues of hydroponically grown Typha and Cladium were shown to increase up to 12 per thousand when grown at elevated levels of P and fixed levels of N (as NH (4) (+) ). The magnitude of changes in delta(15)N resulting from altered discrimination during N uptake is significant compared with other mechanisms affecting plant delta(15)N, and suggests that this may be the dominant mechanism affecting delta(15)N of organic matter following P enrichment. The results of this study have implications for the interpretation of delta(15)N as an indicator of shifts in relative N limitation in wetland ecosystems, and also stress the importance of experimental validation in interpreting delta(15)N patterns.

Synthesis and characterization of a novel liver-targeted prodrug of cytosine-1-beta-D-arabinofuranoside monophosphate for the treatment of hepatocellular carcinoma

Cytotoxic nucleosides have proven to be ineffective for the treatment of hepatocellular carcinoma (HCC) due, in part, to their inadequate conversion to their active nucleoside triphosphates (NTP) in the liver tumor and high conversion in other tissues. These characteristics lead to poor efficacy, high toxicity, and a drug class associated with an unacceptable therapeutic index. Cyclic 1-aryl-1,3-propanyl phosphate prodrugs selectively release the monophosphate of a nucleoside (NMP) into CYP3A4-expressing cells, such as hepatocytes, while leaving the prodrug intact in plasma and extrahepatic tissues. This prodrug strategy was applied to the monophosphate of the well-known cytotoxic nucleoside cytosine-1-beta-D-arabinofuranoside (cytarabine, araC). Compound 19S (MB07133), in mice, achieves good liver targeting compared to araC, generating >19-fold higher cytarabine triphosphate (araCTP) levels in the liver than levels of araC in the plasma and >12-fold higher araCTP levels in the liver than in the bone marrow, representing a >120-fold and >28-fold improvement, respectively, over araC administration.

Syntrophic-archaeal associations in a nutrient-impacted freshwater marsh

AIMS

Evaluation of the composition, distribution and activities of syntrophic bacteria and methanogens in soils from eutrophic and low nutrient regions of a freshwater marsh, and to compare these results with those obtained from a similar study in the Florida Everglades.

METHODS AND RESULTS

Culture dependent and independent approaches were employed to study consortia of syntrophs and methanogens in a freshwater marsh. Methanogenesis from butyrate oxidation was fourfold higher in microcosms containing soil from eutrophic regions of the marsh than from low nutrient regions. Propionate was oxidized in eutrophic microcosms at lower rates than butyrate and with lower yields of methane. Sequence analysis of 16S rRNA gene clone libraries from DNA extracted from microcosms and soils revealed differences such that the dominant restriction fragment length polymorphism (RFLP) phylotypes (representing 82-88% of clone libraries) from eutrophic soils clustered with fatty acid oxidizing Syntrophomonas spp. The four dominant RFLP phylotypes (representing 11-24%) from microcosms containing soils from low nutrient regions were sequenced, and clustered with micro-organisms having the potential for fermentative and syntrophic metabolism. Archaeal 16S rRNA sequence analysis showed that methanogens from eutrophic regions were from diverse families, including Methanomicrobiaceae, Methanosarcinaceae, and Methanocorpusculaceae, but clone libraries from low nutrient soils revealed only members of Methanosarcinaceae.

CONCLUSIONS

These findings indicate that syntroph-methanogen consortia differed with nutrient levels in a freshwater marsh.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is one of few studies addressing the distribution of fatty acid consuming-hydrogen producing bacteria (syntrophs) and their methanogenic partners in wetland soils, and the effects of eutrophication on the ecology these groups.

Peginterferon alfa-2a and ribavirin for chronic hepatitis C genotype 1 infections in black patients: safety, tolerability and impact on sustained virologic response

HCV infections are two-times more prevalent in black Americans than in whites. We previously reported that treatment with peginterferon alfa-2a plus ribavirin produced a sustained virologic response (SVR) rate of 26% in blacks, a lower efficacy compared with the SVR in whites. Here we detail the safety profile of peginterferon alfa-2a plus ribavirin and the relationship between treatment adherence, defined by cumulative drug exposure, and SVR in 78 black patients infected with HCV genotype 1. Sixty-two (79%) patients completed 48 weeks of combination treatment. Peginterferon alfa-2a dose was modified for neutropenia in 36 patients (46%), whereas ribavirin dose was modified due to anemia in 31 patients (40%). The SVR rate was related to medication exposure, based on the percentage of the planned doses of peginterferon and ribavirin that the patients received. The SVR rates were 33, 25 and 0% in patients who received >80, 61-80 and <or=60% of the planned peginterferon, respectively. The SVR rates were 28, 33 and 18% in patients who received >80, 61-80 and <or=60% of the planned ribavirin. The SVR rate was 29% (11 of 38) in patients who received >80% of the total planned doses of both peginterferon and ribavirin and 7% (1 of 14) in patients who received <or=80% of both medicines. The SVR was 30% in patients who received >60% exposure to both, and 0% in patients with <or=60% exposure. In conclusion, peginterferon alfa-2a plus ribavirin demonstrated good safety and tolerability profiles in blacks infected with HCV genotype 1. Adherence to at least >60% of the planned peginterferon alfa-2a and ribavirin doses for 48 weeks was associated with a greater SVR in black patients with HCV genotype 1 infections.

Assessment of the spatial distribution of soil properties in a northern Everglades marsh

Florida Everglades restoration plans are aimed at maintaining and restoring characteristic landscape features such as soil, vegetation, and hydrologic patterns. This study presents the results from an exhaustive spatial sampling of key soil properties in Water Conservation Area 1 (WCA 1), which is part of the northern Everglades. Three soil strata were sampled: floc, upper 0- to 10-cm soil layer, and 10- to 20-cm soil layer. A variety of properties were measured including bulk density (BD), loss on ignition (LOI), total phosphorus (TP), total inorganic phosphorus (TIP), total nitrogen (TN), total carbon (TC), total iron (TFe), total magnesium (TMg), total aluminum (TAl), and total calcium (TCa). Interpolated maps and model prediction uncertainties of properties were generated using geostatistical methods. We found that the uncertainty associated with spatial predictions of floc, particularly floc BD, was highest, whereas spatial predictions of soil chemical properties such as soil Ca were more accurate. The resultant spatial patterns for these soil properties identified three predominant features in WCA 1: (i) a north to south gradient in soil properties associated with the predominant hydrological gradient, (ii) areas of considerable soil nutrient enrichment along the western canal of WCA 1, and (iii) areas of considerable Fe enrichment along the eastern canal. By using geostatistical techniques we were able to describe the spatial dynamics of soil variables and express these predictions with an acceptable level of uncertainty.

Spatial patterns of labile forms of phosphorus in a subtropical wetland

Phosphorus (P) has been identified as the key constituent defining wetland productivity, structure, and function. Our goal was to investigate the spatial patterns of total P and three labile forms of P (labile organic, inorganic, and microbial biomass P) across a subtropical wetland located in east-central Florida, the Blue Cypress Marsh Conservation Area (BCMCA), and link spatial patterns to ecosystem processes. The wetland received a continual input of nutrients primarily from the south and intermittently from the west and east, respectively, which ceased in the mid-1990s. Since then the marsh system has been undergoing natural succession. We used (i) ordinary kriging to characterize the spatial patterns of total P and labile P forms across the wetland, (ii) local, moving spatial correlations to investigate relationships between total P and labile P forms, and (iii) a clustering technique to link the identified spatial patterns to biogeochemical processes. The spatially explicit analyses revealed patterns of total P and labile P forms as well as changing relationships between variables across the marsh. We were able to distinguish P-enriched areas from unaffected ("natural") areas and intermediate zones that are currently undergoing change as P is mobilized and translocated. We also identified areas that are at risk, showing a shift toward a more P-enriched status. Our results improve our understanding of P and its labile components within a spatially explicit context.

Liver targeting of hepatitis-B antiviral lamivudine using the HepDirect prodrug technology

A new class of phosphate and phosphonate prodrugs, called HepDirect prodrugs, has been developed to deliver drugs to the liver while simultaneously diminishing drug exposure to extra-hepatic tissues. The technology combines liver-selective cleavage and kinase by pass with high plasma and tissue stability to achieve increased drug levels in the liver. Lamivudine (LMV), a nucleoside analogue, is a currently approved treatment for hepatitis B infection, but shows modest efficacy and significant drug resistance due to inefficient phosphorylation. LMV is inadequately phosphorylated to the corresponding nucleoside triphosphate in rat and human hepatocytes. A HepDirect prodrug of LMV monophosphate generated 34-fold higher levels of the triphosphate in rat hepatocytes and 320-fold higher triphosphate levels in the liver of treated rats relative to LMV.

Differences in in vitro pollen germination and pollen tube growth of cotton cultivars in response to high temperature

BACKGROUND AND AIMS

High-temperature environments with >30 degrees C during flowering reduce boll retention and yield in cotton. Therefore, identification of cotton cultivars with high-temperature tolerance would be beneficial in both current and future climates. *

METHODS

Response to temperature (10-45 degrees C at 5 degrees C intervals) of pollen germination and pollen tube growth was quantified, and their relationship to cell membrane thermostability was studied in 12 cultivars. A principal component analysis was carried out to classify the genotypes for temperature tolerance. *

KEY RESULTS

Pollen germination and pollen tube length of the cultivars ranged from 20 to 60 % and 411 to 903 microm, respectively. A modified bilinear model best described the response to temperature of pollen germination and pollen tube length. Cultivar variation existed for cardinal temperatures (T(min), T(opt) and T(max)) of pollen germination percentage and pollen tube growth. Mean cardinal temperatures calculated from the bilinear model for the 12 cultivars were 15.0, 31.8 and 43.3 degrees C for pollen germination and 11.9, 28.6 and 42.9 degrees C for pollen tube length. No significant correlations were found between pollen parameters and leaf membrane thermostability. Cultivars were classified into four groups based on principal component analysis. *

CONCLUSIONS

Based on principal component analysis, it is concluded that higher pollen germination percentages and longer pollen tubes under optimum conditions and with optimum temperatures above 32 degrees C for pollen germination would indicate tolerance to high temperature.

Distribution and stability of sulfate-reducing prokaryotic and hydrogenotrophic methanogenic assemblages in nutrient-impacted regions of the Florida Everglades

Although the influence of phosphorus loading on the Everglades ecosystem has received a great deal of attention, most research has targeted macro indicators, such as those based on vegetation or fauna, or chemical and physical parameters involved in biogeochemical cycles. Fewer studies have addressed the role of microorganisms, and these have mainly targeted gross informative parameters such as microbial biomass, enzymatic activities, and microbial enumerations. The objectives of this study were to characterize the dynamics of sulfate-reducing and methanogenic assemblages using terminal restriction fragment length polymorphism (T-RFLP) targeting the dissimilatory sulfite reductase (dsrA) and methyl coenzyme M reductase (mcrA) genes, respectively, and assess the impact of nutrient enrichment on microbial assemblages in the northern Everglades. T-RFLP combined with principal component analysis was a powerful technique to discriminate between soils from sites with eutrophic, transitional, and oligotrophic nutrient concentrations. dsrA T-RFLP provided a higher level of discrimination between the three sites. mcrA was a relatively weaker system to distinguish between sites, since it could not categorically discriminate between eutrophic and transition soil samples, but may be useful as an early indicator of phosphorus loading which is altering hydrogenotrophic methanogenic community in the transition zones, making them more similar to eutrophic zones. Clearly, targeting a combination of different microbial communities provides greater insight into the functioning of this ecosystem and provides useful information for understanding the relationship between eutrophication effects and microbial assemblages.

MB06322 (CS-917): A potent and selective inhibitor of fructose 1,6-bisphosphatase for controlling gluconeogenesis in type 2 diabetes

In type 2 diabetes, the liver produces excessive amounts of glucose through the gluconeogenesis (GNG) pathway and consequently is partly responsible for the elevated glucose levels characteristic of the disease. In an effort to find safe and efficacious GNG inhibitors, we targeted the AMP binding site of fructose 1,6-bisphosphatase (FBPase). The hydrophilic nature of AMP binding sites and their widespread use for allosteric regulation of enzymes in metabolic pathways has historically made discovery of AMP mimetics suitable for drug development difficult. By using a structure-based drug design strategy, we discovered a series of compounds that mimic AMP but bear little structural resemblance. The lead compound, MB05032, exhibited high potency and specificity for human FBPase. Oral delivery of MB05032 was achieved by using the bisamidate prodrug MB06322 (CS-917), which is converted to MB05032 in two steps through the action of an esterase and a phosphoramidase. MB06322 inhibited glucose production from a variety of GNG substrates in rat hepatocytes and from bicarbonate in male Zucker diabetic fatty rats. Analysis of liver GNG pathway intermediates confirmed FBPase as the site of action. Oral administration of MB06322 to Zucker diabetic fatty rats led to a dose-dependent decrease in plasma glucose levels independent of insulin levels and nutritional status. Glucose lowering occurred without signs of hypoglycemia or significant elevations in plasma lactate or triglyceride levels. The findings suggest that potent and specific FBPase inhibitors represent a drug class with potential to treat type 2 diabetes through inhibition of GNG.

Interactive effects of carbon dioxide, temperature, and ultraviolet-B radiation on soybean (Glycine max L.) flower and pollen morphology, pollen production, germination, and tube lengths

Plant reproduction is highly vulnerable to global climate change components such as carbon dioxide concentration ([CO(2)]), temperature (T), and ultraviolet-B (UV-B) radiation. The objectives of this study were to determine the effects of season-long exposure to treatments of [CO(2)] at 360 (control) and 720 micromol mol(-1) (+CO(2)), temperature at 30/22 degrees C (control) and 38/30 degrees C (+T) and UV-B radiation 0 (control) and 10 kJ m(-2) d(-1) (+UV-B) on flower and pollen morphology, pollen production, germination, and tube lengths of six soybean genotypes (D 88-5320, D 90-9216, Stalwart III, PI 471938, DG 5630RR, and DP 4933RR) in sunlit, controlled environment chambers. The control treatment had 360 micromol mol(-1) [CO(2)] at 30/22 degrees C and 0 kJ UV-B. Plants grown either at +UV-B or +T, alone or in combination, produced smaller flowers with shorter standard petal and staminal column lengths. Flowers so produced had less pollen with poor pollen germination and shorter tube lengths. Pollen produced by the flowers of these plants appeared shrivelled without apertures and with disturbed exine ornamentation even at +CO(2) conditions. The damaging effects of +T and +UV-B were not ameliorated by +CO(2) conditions. Based on the total stress response index (TSRI), pooled individual component responses over all the treatments, the genotypes were classified as tolerant (DG 5630RR, D 88-5320: TSRI >-790), intermediate (D 90-9216, PI 471938: TSRI <-790 to >-1026), and sensitive (Stalwart III, DP 4933RR: TSRI <-1026). The differences in sensitivity identified among genotypes imply the options for selecting genotypes with tolerance to environmental stresses projected to occur in the future climates.

Optimization of low-cost phosphorus removal from wastewater using co-treatments with constructed wetlands

Eighteen wastewater treatment systems were operated for one year to investigate phosphorus (P) removal. Systems paired co-treatment reactors containing iron or calcium drinking water treatment residuals with vertical-flow constructed wetland mesocosms planted with Schoenoplectus tabernaemontani (K.C. Gmel.) Palla. For secondary municipal wastewater, soluble reactive P (SRP) concentrations were reduced from 0.70 to 0.03 mg L(-1) (95%) or 0.01 mg L(-1) (98%) by systems with the calcium or iron co-treatments, respectively (compared to 0.09 mg L(-1) or 87% by controls). Total P (TP) concentrations were reduced from 1.00 to 0.07 mg L(-1) (93%) and 0.05 mg L(-1) (95%) by the same treatments (compared to 0.16 mg L(-1) or 84% by controls). For anaerobically digested dairy wastewater, SRP was reduced from 7.68 to 6.43 mg L(-1) (16%) or 5.95 mg L(-1) (22%) by the systems with calcium or iron, respectively (compared to 7.37 mg L(-1) or 4% by controls). For this wastewater, the TP was reduced from 48.5 to 22.5 mg L(-1) (53%) and 22.7 mg L(-1) (53%) by the same treatments (compared to 24.1 mg L(-1) or 50% by controls) but performance improved substantially with a design modification tested.

Response of biogeochemical indicators to a drawdown and subsequent reflood

Temporal oscillations in hydrology are a common occurrence in wetlands and can result in alternating flooded and drained conditions in the surface soil. These oscillations in water levels can stimulate microbial activities and result in the mobilization and redistribution of significant amounts of carbon (C), nitrogen (N), and phosphorus (P). The goal of this study was to experimentally simulate a drawdown and reflood of marsh soil from a nutrient-enriched site and a reference site of a wetland (Blue Cypress Marsh Conservation Area, Florida). The goal was to better understand the changes in biogeochemistry and microbial activities present in these soils as a result of hydrological fluctuations. Measurements of dissolved reactive phosphorus (DRP), ammonia, and nitrate in the floodwater indicated significantly higher (alpha = 0.05) NH(4)(+) and DRP fluxes from the nutrient-enriched site; floodwaters in the cores from both sites contained significant NO(3)(-) concentrations (9.6 mg N L(-1)), which was rapidly consumed over the core incubation period (30 d). Water level drawdown and reflooding initially stimulated the soil microbial biomass, methanogenic rates, and extracellular enzyme activities (acid phosphatase and beta-glucosidase). The anaerobic microbial metabolic activities (CO(2)) where initially significantly (alpha = 0.05) enhanced by the reflood, resulting in roughly equivalent rates as the aerobic respiratory activities (CO(2)), presumably as a function of the high water column NO(3)(-) levels. This study illustrates that the reflood event in the hydrological cycles in a wetland can significantly stimulate the activities of hydrolytic enzymes and microbiological communities in these soils.