Evaluating phytochemical and microbial contributions to atrazine degradation.

The inclusion of warm-season grasses, such as switchgrass (Panicum virgatum) and eastern gamagrass (EG) (Tripsacum dactyloides), in vegetated buffer strips has been shown to mitigate herbicide contamination in runoff and increase herbicide degradation in soil. The mode of action by which buffer strip rhizospheres enhance herbicide degradation remains unclear, but microorganisms and phytochemicals are believed to facilitate degradation processes. The objectives of this study were to: 1) screen root extracts from seven switchgrass cultivars for the ability to degrade the herbicide atrazine (ATZ) in solution; 2) determine sorption coefficients (Kd) of the ATZ-degrading phytochemical 2-ß-D-glucopyranosyloxy-4-hydroxy-1,4-benzoxazin-3-one (DBG) to soil and Ca-montmorillonite, and investigate if DBG or ATZ sorption alters degradation processes; and 3) quantify ATZ degradation rates and soil microbial response to ATZ application in mesocosms containing soil and select warm-season grasses. Phytochemicals extracted from the roots of switchgrass cultivars degraded 44-85% of ATZ in 16-h laboratory assays, demonstrating that some switchgrass cultivars could rapidly degrade ATZ under laboratory conditions. However, attempts to isolate ATZ-degrading phytochemicals from plant roots were unsuccessful. Sorption studies revealed that DBG was strongly sorbed to soil (Kd = 87.2 L kg-1) and Ca-montmorillonite (Kd = 31.7 L kg-1), and DBG driven hydrolysis of ATZ was entirely inhibited when either ATZ or DBG were sorbed to Ca-montmorillonite. Atrazine degradation rates in mesocosm soils were rapid (t0.5 = 8.2-11.2 d), but not significantly different between soils collected from the two switchgrass cultivar mesocosms, the eastern gamagrass cultivar mesocosm, and the unvegetated mesocosm (control). Significant changes in three phospholipid fatty acid biomarkers were observed among the treatments. These changes indicated that different ATZ-degrading microbial consortia resulted in equivalent ATZ degradation rates between treatments. Results demonstrated that soil microbial response was the dominant mechanism controlling ATZ degradation in the soil studied, rather than root phytochemicals.

Equine herpesvirus-1 genotype did not significantly affect clinical signs and disease outcome in 65 horses diagnosed with equine herpesvirus-1 myeloencephalopathy.

The objective of this study was to determine if the genotype of equine herpesvirus-1 (EHV-1) impacted clinical disease and outcome of horses with laboratory confirmed equine herpesvirus myeloencephalopathy (EHM). Medical records from 65 horses diagnosed with EHM from 2011 to 2019 were reviewed for signalment, presence and severity of clinical signs (lethargy, fever, ataxia, urinary incontinence) and outcome. Horses were further grouped based on the EHV-1 genotype into neuropathic (D752) or non-neuropathic (N752) EHV-1 infection. Between the two EHV-1 genotype groups, age and sex distributions were similar, although breed distribution was different (Quarter Horses and Saddlebreds were overrepresented and Warmbloods were underrepresented in the EHV-1 D752 group compared to the EHV-1 N752 group; P = 0.009). Lethargy, fever, ataxia and outcome were not significantly different between the two EHV-1 genotype groups (P > 0.05). However, urinary incontinence was significantly more frequently reported in horses infected with the D752 genotype of EHV-1 (P=0.04). Contrary to previous studies, the present study showed no difference in frequency of genotype (D752 or N752) among 65 horses with EHM and, with the exception of urinary incontinence, no difference in clinical disease or outcome related to the EHV-1 genotype.

Corneal Cross-Linking: An Effective Treatment Option for Pellucid Marginal Degeneration.

Purpose: This is the first review article examining literature specific to the use of corneal cross-linking (CXL) to treat pellucid marginal degeneration (PMD). Results: CXL appears to be an effective treatment that may halt the progression of PMD to stabilize vision. This could postpone or eliminate the need for corneal transplantation in the management of these patients. Furthermore, combining CXL with keratorefractive surgery in a single procedure has been shown to be safe and successful in improving vision in PMD patients. Conclusions: The data reported in literature is limited at this time, consisting mostly of retrospective studies with short term follow up. Further research is needed to evaluate refractive effects of combined CXL and excimer laser procedures.

Incretin-based medications for type 2 diabetes: an overview of reviews.

AIMS: To summarize evidence from and assess the quality of published systematic reviews evaluating the safety, efficacy and effectiveness of incretin-based medications used in the treatment of type 2 diabetes. METHODS: We identified systematic reviews of randomized controlled trials or observational studies published in any language that evaluated the safety and/or effectiveness of glucagon-like peptide-1 (GLP-1) receptor agonists or dipeptidyl-peptidase-4 (DPP-4) inhibitors. Data sources used include the Cochrane Library, PubMed, EMBASE, Web of Science, International Pharmaceutical Abstracts, table of contents of diabetes journals, and hand-searching of reference lists and clinical practice guidelines. The methodological quality of systematic reviews was independently assessed by two reviewers using the Assessment of Multiple Systematic Reviews (AMSTAR) checklist. Our study protocol was registered with PROSPERO (2013:CRD42013005149). The primary outcomes were pooled treatment effect estimates for glycaemic control, macrovascular and microvascular complications, and hypoglycaemic events. RESULTS: We identified 467 unique citations of which 84 systematic reviews met our inclusion criteria. There were 51 reviews that evaluated GLP-1 receptor agonists and 64 reviews that evaluated DPP-4 inhibitors. The median (interquartile range) AMSTAR score was 6 (3) out of 11 for quantitative and 1 (1) for non-quantitative reviews. Among the 66 quantitative systematic reviews, there were a total of 718 pooled treatment effect estimates reported for our primary outcomes and 1012 reported pooled treatment effect estimates for secondary outcomes. CONCLUSIONS: Clinicians and policy makers, when using the results of systematic reviews to inform decision-making with regard to round clinical care or healthcare policies for incretin-based medications, should consider the variability in quality of reviews.

Single molecule detection of direct, homologous, DNA/DNA pairing.

Using a parallel single molecule magnetic tweezers assay we demonstrate homologous pairing of two double-stranded (ds) DNA molecules in the absence of proteins, divalent metal ions, crowding agents, or free DNA ends. Pairing is accurate and rapid under physiological conditions of temperature and monovalent salt, even at DNA molecule concentrations orders of magnitude below those found in vivo, and in the presence of a large excess of nonspecific competitor DNA. Crowding agents further increase the reaction rate. Pairing is readily detected between regions of homology of 5 kb or more. Detected pairs are stable against thermal forces and shear forces up to 10 pN. These results strongly suggest that direct recognition of homology between chemically intact B-DNA molecules should be possible in vivo. The robustness of the observed signal raises the possibility that pairing might even be the "default" option, limited to desired situations by specific features. Protein-independent homologous pairing of intact dsDNA has been predicted theoretically, but further studies are needed to determine whether existing theories fit sequence length, temperature, and salt dependencies described here.

Demonstration that the shear force required to separate short double-stranded DNA does not increase significantly with sequence length for sequences longer than 25 base pairs.

We have measured the shear force for short double-stranded DNA sequences pulled by either the 3'3' or 5'5' ends and find that the shear force is independent of the pulling technique. For the 50% GC sequences examined, the force is a linear function of DNA length up to 20 base pairs (bp); however, we show that, as predicted by deGennes, the shear force approaches an asymptotic value in the limit where the number of base pairs approaches infinity, where the shear force for a 32 bp sequence is within 5% of the asymptotic value of 61.4 pN . Fits to deGennes' theory suggest that the shear force is distributed over fewer than 10 bp at the end of the sequence, with the rest of the sequence experiencing negligible shear force. The single base pair rupture force and the ratio of the backbone spring constant to the base pair spring constant determined from fits of the data to deGennes' theory are consistent with ab initio predictions.

Measurement of the salt-dependent stabilization of partially open DNA by Escherichia coli SSB protein.

The rezipping force of two complementary DNA strands under tension has been measured in the presence of Escherichia coli single-stranded-binding proteins under salt conditions ranging from 10- to 400 mM NaCl. The effectiveness of the binding protein in preventing rezipping is strongly dependent on salt concentration and compared with the salt dependence in the absence of the protein. At concentrations less than 50 mM NaCl, the protein prevents complete rezipping of lambda-phage on the 2-s timescale of the experiment, when the ssDNA is under tensions as low as 3.5 +/- 1 pN. For salt concentrations greater than 200 mM NaCl, the protein inhibits rezipping but cannot block rezipping when the tension is reduced below 6 +/- 1.8 pN. This change in effectiveness as a function of salt concentration may correspond to salt-dependent changes in binding modes that were previously observed in bulk assays.

Direct measurements of the stabilization of single-stranded DNA under tension by single-stranded binding proteins.

The unzipping and rezipping of a double-stranded DNA molecule is carried out in the presence of two single-stranded binding proteins T4 gp32 and E. Coli SSB protein to determine the effect of the proteins on the stability of single- and double-stranded DNA. The proteins do not have a significant effect on unzipping, indicating that the two proteins do not destabilize the double-stranded DNA; however, both proteins inhibit rezipping. At protein concentrations where the rezipping force response is saturated, E. Coli SSB protein reduces the rezipping force to 5.5+/-1.5 pN , while T4 gp32 completely blocks rezipping on the time scale of the experiment.

Measurements of the hysteresis in unzipping and rezipping double-stranded DNA.

Complete unzipping and rezipping of lambda -phage double-stranded DNA is achieved by applying a constant force. A strong hysteresis is observed at all tested time scales and temperatures. Hysteresis also occurs for partial unzipping, indicating stability for the partially open state over a force range of 2- 5pN . Results are compared to nearest-neighbor model simulations, and reasonable agreement is found.

Ultraviolet protection factor of fabrics: comparison of laboratory and field-based measurements.

BACKGROUND/PURPOSE: Spectrophotometry has become an accepted laboratory-based method for the determination of the ultraviolet protection factor (UPF) of fabrics. However, the validity of the UPF determined in the laboratory has been a controversial issue with regard to its significance in the field. To compare UPF values obtained by spectrophotometry, determination of the minimal erythema dose (MED), and biological dosimetry, we conducted laboratory and field-based measurements on various fabric materials. METHODS: One cotton, two viscose, and two polyester fabrics were enrolled into the study. Spectrophotometric (SP) testing was performed in accordance with the European standard. In vivo "on skin" (IV) testing on human subjects was performed with and without fabric protection. For determination of MED, a solar-simulator was used. In another part of the study, biological dosimetry (BD) testing was employed for laboratory testing with solar-simulated radiation (laboratory BD testing) as well as field-based measurements with natural sunlight in stationary (stationary BD testing) and "real life" exposure situations (mobile subject BD testing). For field-based measurements one light-weight polyester fabric was selected. RESULTS: The differences of the mean UPF values obtained by the laboratory-based methods were significant (MANOVA; P = 0.05), except for fabric no. 2 (MANOVA; P = 0.097). In 4 of the 5 fabrics tested, UPF values obtained by IV testing were significantly lower than those obtained by SP testing (t-test; P = 0.05). In 3 fabrics, SP testing revealed significantly higher UPF values in comparison to laboratory BD testing (t-test; P = 0.05). The differences of UPF values obtained by the laboratory and field-based measurements employed for the light-weight polyester fabric were significant (ANOVA; P = 0.05). In comparison to SP testing (UPF 3.8), stationary BD testing resulted in significantly lower (UPF 3.5) and mobile subject BD testing in a significantly higher UPF of 4.4 (t-test; P = 0.05). The UPF obtained by mobile subject BD testing differed significantly from the UPF obtained by stationary BD testing (t-test; P = 0.05). CONCLUSIONS: Comparison of the presented methods indicates that IV testing generally results in lower UPF values. By contrast BD testing in "real life" exposure situations reveals relatively high UPF values. Although an overestimation of the spectrophotometrically measured UPF has been observed in comparative laboratory testing, UPF values obtained by field-based measurements are in relatively good agreement, or even surpass UPF values obtained by spectrophotometry. It is, therefore, suggested that SP testing provides "safe" UPF values which may be also valid in extreme real exposure situations. Biological UV dosimetry is, however, a promising alternative method for UPF testing: the test is easily performed in realistic exposure situations, the test is relatively inexpensive, and the measurements are valid.

Carbon isotope ratios in exhaled CO(2) can be used to determine not just present, but also past diets in birds.

We show that an animal's past and present diet can be distinguished through the delta(13)C of exhaled CO(2). The exhaled delta(13)C of 12 pigeons fed solely corn (a C(4) plant) for 30 days was -13.63 per thousand (+/-0.30). We then fed six pigeons wheat (a C(3) plant) and continued to feed the other six corn. After 48 h the exhaled delta(13)C from the corn-fed pigeons was unchanged; that from the wheat-fed pigeons was -20.5 per thousand. We then fasted three of the wheat-fed pigeons for 3 days, after which their exhaled delta(13)C was -14.96 per thousand, while it was -13.57 per thousand in corn-fed pigeons, and -22.22 per thousand in pigeons that continued on wheat. Thus, we could infer diet from the (13)C/(12)C ratios of exhaled CO(2). Significantly, breath samples from fasted pigeons also revealed that they had eaten corn when their lipid stores were formed. We also showed that the change in the (13)C/(12)C of exhaled CO(2) had a half-life of approximately 3.5 h, and a time constant of approximately 6.7 h. Thus one can infer past and present diet from exhaled delta(13)C alone, if the initial breath sample is followed by a fasted breath sample, without harming the animal or having to recapture it successively.

Human papillomavirus infection at the United States-Mexico border: implications for cervical cancer prevention and control.

The United States-Mexico border is a region comprised of a country with one of the highest rates of invasive cervical cancer (Mexico) and a country with one of the lowest rates (United States). Recent evidence clearly indicates that human papillomavirus (HPV) infection is the cause of cervical cancer. The distribution of specific types of HPV is known to vary in different regions of the world, as do the cofactors that may inhibit or promote HPV carcinogenesis. Estimating the prevalence of oncogenic HPV is needed for guiding vaccine development. The purpose of this study was to determine the prevalence of oncogenic and nononcogenic HPV types and risk factors for HPV among women residing along the United States-Mexico border. A cross-sectional study of 2319 women, ages 15-79 years, self-referring for gynecological care was conducted between 1997 and 1998. HPV was detected by PCR using the PYGMY 09/11 L1 consensus primer, and HPV genotyping was conducted using the reverse line blot method. Overall, the HPV prevalence was 14.4% with no significant differences observed by country after adjustment for age. HPV 16 was the most commonly detected HPV type in both the United States and Mexico. Among women with high-grade squamous intraepithelial lesions, HPV types 58, 45, 51, 31, 35, 55, and 73 were most common in Mexico, and HPV types 18, 31, 35, 51, 52, and 58 were most common in the United States. In both countries, HPV prevalence declined linearly with age from 25% among women ages 15-19 years to 5.3% among women 56-65 years. Factors significantly independently associated with HPV infection were older age [adjusted odds ratio (AOR) = 0.15 for ages 56-65 years compared with those 15-19 years], a marital status other than married (AOR = 1.58-3.29), increased numbers of lifetime male partners (AOR = 3.8 for > or =10 partners compared with 1 partner), concurrent infection with Chlamydia trachomatis (AOR = 1.79), ever use of Norplant (AOR = 2.69), and current use of injectable contraceptives (AOR = 2.29). Risk factors for HPV infection did not differ by country. Results from this study suggest that in addition to HPV 16 and 18, HPV types 31, 45, 51, and 58 should be considered for inclusion in an HPV prevention vaccine for distribution in Mexico.

The correlation between colposcopically directed cervical biopsy and loop electrosurgical excision procedure pathology and the effect of time on that agreement.

OBJECTIVE: The goal of this study was to evaluate whether colposcopically directed cervical biopsy accurately predicts histopathology found on loop electrosurgical excision procedure specimen and to assess whether this correlation was affected by a delay in treatment of greater than 12 weeks. METHODS: A retrospective review was performed of all cervical biopsy and loop electrosurgical excision procedure pairs performed at University of Arizona Medical Center between March 1992 and March 2000. Agreement was assessed by kappa statistics and Spearman rho coefficients. A subgroup analysis was performed to assess the effect of a delay greater than 12 weeks between cervical biopsy and loop excision on the histopathologic correlation. RESULTS: An 84% agreement was found between cervical biopsy histopathology and loop electrosurgical excision procedure histopathology when compared to within 1 degree (kappa = 0.78, P < 0.0001; Spearman rho = 0.40, P < 0.0001). This agreement remained strong (87%) even when loop electrosurgical excision procedure was delayed greater than 12 weeks (kappa = 0.81, P = 0.01). CONCLUSION: Colposcopically directed cervical biopsy correlated strongly with loop specimen histopathology. A delay in loop electrosurgical excision procedure greater than 12 weeks does not negatively affect this correlation. This delay of 12 weeks may be used safely in the future to test chemotherapeutic dysplasia treatments.

Nuclear chromatin patterns in normal, hyperplastic and atypical endometrium.

OBJECTIVE: To characterize the nuclei of endometrial lesions for the diagnostic categories of normal glandular tissue, simple hyperplasia, atypical hyperplasia and adenocarcinoma of the endometrium, with the specific goal of probing for heterogeneity. STUDY DESIGN: For each diagnostic category the images of 360 nuclei were recorded on a high-resolution video microphotometer. Features descriptive of the statistical and spatial distribution of nuclear chromatin were computed for each nucleus. A nonsupervised learning algorithm, P-index, was employed to establish subsets of nuclei within each diagnostic category and to determine whether these subsets were statistically significantly different in the nuclear chromatin pattern. RESULTS: Lesions from cases of hyperplasia, atypical hyperplasia and adenocarcinoma of the endometrium each contained several subsets of nuclei with statistically significantly different chromatin patterns. For one such subset from each diagnostic category, a clear trend of progression toward adenocarcinoma could be demonstrated. CONCLUSION: The nuclei in endometrial lesions represent a highly heterogeneous set. Any measure of lesion progression or regression due to chemopreventive intervention, in an individual case, will have to examine the proportion of nuclei in each of these subsets as well as measures of deviation from normal for each subset.

Design and results of the USA-Mexico border human papillomavirus (HPV), cervical dysplasia, and Chlamydia trachomatis study.

OBJECTIVE: Mexico has one of the highest mortality rates of invasive cervical cancer in the world. This is particularly true for the states in northern Mexico that border on the United States of America. In addition, Hispanics in the United States have higher rates than do non-Hispanics in the country. Therefore, a binational team was formed to focus on this problem and to determine the risk factors and prevalence of cervical dysplasia and human papillomavirus (HPV) infection, the sexually transmitted disease (STD) known to cause cervical cancer. Chlamydia trachomatis infection, a common STD and potential HPV cofactor, was also assessed. METHODS: Research was conducted in 1997 and 1998 in the border region of two states, Arizona in the United States and Sonora in Mexico, applying a cross-sectional study of women attending clinics for routine gynecologic care. Clinical measurements included Pap smears, HPV infection by both polymerase chain reaction (PCR) and Hybrid Capture (HC), and C. trachomatis status by HC and enzyme-linked immunoassay (EIA). A total of 2,436 women were enrolled (mean age 33.3 years +/- 10.3 years). RESULTS: The overall prevalence of abnormal cytology was 9.3%, with a significant difference in the prevalence in Mexico (11.4%) vs. the United States (6.6%). Of the participants, 14.5% of them tested positive for HPV by PCR, with no significant difference between the two countries, in spite of a lower behavioral risk profile for the Mexican women. Overall prevalence of C. trachomatis was found to be greater by HC than by EIA (8.2% vs. 3.0%), and in Mexico higher by both methods. CONCLUSIONS: An important accomplishment of the project was the implementation of a quality control program for Pap smear collection, which resulted in a significant reduction in inadequate smears in Mexico. Despite numerous potential logistical barriers, the binational team successfully conducted a large-scale study in the border area and developed an infrastructure for future research.

Chlamydia trachomatis and Pap testing from a single, fluid-based sample. A multicenter study.

OBJECTIVE: To determine the potential for both Pap testing and the Chlamydia direct fluorescence assay (DFA) from a single sample using the fluid-based ThinPrep Pap Test method (Cytyc Corporation, Boxborough, Massachusetts). STUDY DESIGN: Conventional DFA was compared to ThinPrep DFA in a direct-to-vial, double-blinded, multicenter protocol. Cervical scrapings were collected for the ThinPrep Pap Test, and then a second swab was used to collect an endocervical sample for a conventional DFA test. The DFA slide prepared from the ThinPrep Test and the conventional DFA sample prepared from the endocervical swab were evaluated independently. Discrepant cases were adjudicated by testing residual specimens using a Chlamydia direct DNA method. RESULTS: Combining 636 adequate cases (94% of the total collected), 582 (91.5%) were negative on both slides, 43 (6.8%) positive by both and 11 (1.7%) discrepant. The prevalence of Chlamydia was 7.9% based on the conventional DFA method (range, 4.3-10.9%). McNemar's two-tailed test indicated the results not to be statistically different (P > .05). Adjudication favored ThinPrep 45% of the time and conventional 55%. Specimen adequacy favored ThinPrep with high statistical significance (McNemar's test, P > .01). CONCLUSION: A second slide prepared from the same vial of cells as that used for the ThinPrep Pap Test can be used for Chlamydia testing by DFA. Fluid-based collection could allow multiple tests from a single sample.

How does time since feeding affect the fuels pigeons use during flight?

Time between meals can vary from multiple hours to days within and among species. We investigated the effects of time since feeding on lipid, protein, and carbohydrate oxidation in flying pigeons (Columba livia) by interpreting changes in blood plasma metabolite concentrations and mass during flight. Five pigeons were flown or rested for 4 h after food deprivations of 2, 12, 24, and 48 h. After flight, blood plasma concentrations of uric acid and beta-hydroxybutyrate were elevated over control and preflight values, indicating elevated protein and lipid catabolism during flight. Lipid oxidation, as indicated by changes in beta-hydroxybutyrate concentration, increased more in unfed flying pigeons compared with recently fed flying pigeons and with resting controls. Protein oxidation, as indicated by changes in uric acid concentrations, also positively covaried with feeding time; the covariation was mostly caused by increases in 48-h food-deprived pigeons. Unfed birds lost less mass during a 4-h flight than recently fed birds. We reasoned that recently fed pigeons oxidized more glycogen in flight than pigeons not recently fed; calculated glycogen stores explained 72%-117% of mass loss differences between 2- and 48-h-fed pigeons. Thus, time since feeding was an important determinant of the fuels pigeons used in flight.

Colocalization of CaM KII and MAP kinase on architectural elements of the mouse egg: potentiation of MAP kinase activity by CaM KII.

The conversion of the egg to a zygote requires the initiation of several signaling pathways that act in an orchestrated fashion to rapidly remodel the egg. Architectural elements within the egg can serve to localize components of these signaling pathways and colocalization of such components provides the opportunity for interaction between different signaling pathways. This study examines the localization as well as the state of activation of two different kinases, MAP kinase and calcium/calmodulin-dependent protein kinase II (CaM KII). The meiotic spindle serves as a site for enrichment of these kinases. However, activated MAP kinase and activated CaM KII exhibit a developmental stage-specific pattern of localization that represents a subset of the area occupied by the distribution of the total mass of MAP kinase and CaM KII. Suppression of CaM KII activity results in reduction in the amount of MAP kinase as well as a decreased level of activity of MAP kinase. Since CaM KII becomes active as a result of fertilization, the former kinase could serve to potentiate MAP kinase activity and the colocalization of these two kinases may facilitate such an interaction.

Textile dye allergic contact dermatitis prevalence.

This article summarizes textile dye prevalence studies and makes recommendations for advancing knowledge about textile-dye sensitization. Prevalence data is provided by study and by dye. Dermatology teams are encouraged to conduct textile-dye prevalence studies in countries other than Italy, include dyes for which the least prevalence data has been collected, to standardize method of application and reading, and to verify purity and identity of dyes used for patch testing. Testing with pure dyes and other chemicals in dye formulations should provide insights in choosing dye systems that will decrease sensitization.