Postoffer Pre-Placement Screening for Carpal Tunnel Syndrome in Newly Hired Manufacturing Workers

OBJECTIVE: We determined the predictive validity of a post-offer pre-placement (POPP) screen using nerve conduction velocity studies (NCV) to identify future cases of carpal tunnel syndrome (CTS). METHODS: A cohort of 1648 newly hired manufacturing production workers underwent baseline NCS, and were followed for 5 years. RESULTS: There was no association between abnormal POPP NCV results and incident CTS. Varying NCV diagnostic cut-offs did not improve predictive validity. Workers in jobs with high hand/wrist exposure showed greater risk of CTS than those in low exposed jobs (Relative Risk 2.82; 95% CI 1.52, 5.22). CONCLUSIONS: POPP screening seems ineffective as a preventive strategy for CTS

Rapid Quantitative Analysis of Toxic Norditerpenoid Alkaloids in Larkspur (Delphinium spp.) by Flow Injection - Electrospray Ionization – Mass Spectrometry

A rapid flow injection - electrospray ionization – mass spectrometry (FI-ESI-MS) method for the quantitative and qualitative analysis of norditerpenoid alkaloids in larkspur plants was developed. The FI-ESI-MS method was calibrated for alkaloid concentrations with larkspur plant samples against an existing Fourier transform infrared spectroscopy FTIR method. There was a strong correlation (r = 0.9926, r = 0.9891) between the FTIR and FI-ESI-MS methods. The relative standard deviation (RSD) for all measurements were ≤ 6.2 % except for the sample with the lowest concentration which was 19%. The sample throughput of the FI-ESI-MS method is much higher than the FTIR method due to simpler sample preparation, autosampling capabilities, and short analysis times. Finally, the FIA-ESI-MS can be used to qualitatively analyze the alkaloids in larkspur samples since the data allows the observation of all ions that comprise the alkaloid signals

Broom Snakeweed Extracts Dosed to Late-Term Pregnant Cattle Do Not Cause Premature Parturition

Broom snakeweed [Gutierrezia sarothrae (Pursh) Britton and Rusby] and threadleaf snakeweed [G. microcephala (DC.) A. Gray] are found on many rangelands in western North America. Snakeweeds are generally unpalatable; however, animals will graze them when other forage is not available and there are field reports that pregnant cows that graze snakeweeds may abort calves. Subsequent feeding studies using fresh cut snakeweed, ground and gavaged into pregnant cattle have failed to reproduce abortions, though it was evident that at high doses snakeweed quickly damaged the rumen microflora resulting in severe rumen atony, bloating and acidosis. We report here an attempt to solvent extract the snakeweeds, mix the extracts with ground alfalfa hay, and test the extracts for abortifacient activity in late-term pregnant cattle. The dosed extracts again appear to be unable to reproduce snakeweed induced abortions in cattle. Extracts from snakeweed chemotype 1 plant appear to be quite toxic to the rumen and caused complete rumen stasis after 2-3 days. In contrast, cattle receiving chemotype 2 extracts were able to tolerate over twice the dosage as that given for chemotype 1 extracts. We conclude that broom snakeweed plants are unlikely to be directly responsible for cattle abortions observed in cattle grazing snakeweed infested rangelands. It is more likely that cattle may be affected by rumen toxicity and/or might suffer from poor nutritional factors given the lack of quality forage that might be available on rangelands with high snakeweed infestation

THE ISOLATION AND IDENTIFICATION OF STEROIDAL SAPOGENINS IN SWITCHGRASS

Switchgrass (Panicum virgatum L.) has been reported to be hepatotoxic, causing photosensitization in lambs and horses. In this study we show the presence of steroidal saponins in two samples of switchgrass that has been implicated in the poisonings of sheep and horses. After hydrolysis of the saponins, diosgenin was determined to be the major sapogenin in both switchgrass samples. We also confirmed the presence of diosgenin in kleingrass after hydrolysis of saponins extracted from it

Spontaneous outbreak of Astragalus pehuenches (Fabaceae) poisoning in cattle in Argentina

This is the first report of a spontaneous outbreak of Astragalus pehuenches poisoning on a farm in Argentine Patagonia, where 63 out of 70 cattle died. The main clinical signs of affected animals were ataxia, balance loss and progressive emaciation. Purkinje cells presented vacuolation and marginalization of the nucleus. Astragalus pehuenches was detected in the paddock as well as in the ruminal content and fecal matter samples of the affected animals. Swainsonine concentrations in Astragalus specimens were found to be as high as 0.096%.Estación Experimental Agropecuaria BarilocheFil: Martínez Agustín. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Área Producción Animal.Grupo Salud Animal; ArgentinaFil: Lauroua, Catalina. Universidad Nacional del Centro de la Provincia de Buenos Aires; ArgentinaFil: Borrelli, Laura Beatriz. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Laboratorio de Microhistología; ArgentinaFil: Gardner, Dale R. Poisonous Plant Research Laboratory Logan; Estados UnidosFil: Robles, Carlos Alejandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Área de Producción Animal. Grupo Salud Animal; Argentin

Livestock preference for endophyte-infected or endophyte-free Oxytropis sericea, Ipomoea carnea, and Ipomoea asarifolia

Fungal endophyte-infected forages have been shown to alter herbivore feeding preferences. The objective of this experiment was to compare the preference of cattle, sheep, and goats for plants containing (E+) and not containing (E-) fungal endophytes using freshly harvested Oxytropis sericea, Ipomoea carnea, and Ipomoea asarifolia. Goats and sheep rejected all forage choices regardless of endophyte status except for grass and alfalfa hay. Endophyte status had no influence on cattle forage preferences. Cattle rejected all Oxytropis sericea E+ and E- choices. Cattle discriminated between Ipomoea species, preferring Ipomoea carnea to Ipomoea asarifolia (P = 0.004). In all comparisons, Ipomoea carnea was selected over Ipomoea asarifolia. Cattle did not discriminate between E+ and E- plants of either species (P \u3e 0.33). Cattle preferred E+ Ipomoea carnea over E- Ipomoea asarifolia (P = 0.03), E- Ipomoea carnea over E- Ipomoea asarifolia (P = 0.003), E- Ipomoea carnea over E+ Ipomoea asarifolia (P = 0.001), and E+ Ipomoea carnea over E+ Ipomoea asarifolia (P = 0.01). Nutritional composition, including nonstructural carbohydrate concentrations, did not explain cattle preferences, as Ipomoea asarifolia contained higher total carbohydrate concentrations than did Ipomoea carnea. The presence of ergot and indole diterpene alkaloids in E+ Ipomoea asarifolia, or swainsonine in E+ Oxytropis sericea and E+ Ipomoea carnea did not influence cattle preference because cattle did not discriminate between E- and E+ plants. This study suggests that for these specific toxic plants, endophyte status plays no part in preferences of grazing cattle. For grazing animals, selection by livestock is related to forage scarcity or low nutrient content in the other available forage

Embryotoxic Effects of Three Natural Occurring \u3cem\u3eVeratrum\u3c/em\u3e Alkaloids and One Synthetic Analog using In Vitro Produced Bovine Embryos

Three natural occurring plant toxins from Veratrum californicum and one related synthetic analog were screened for embryotoxicity using in vitro bovine embryo production techniques. Bovine oocytes were aspirated from ovaries collected from a local abattoir and embryos were generated through in vitro maturation (IVM) and in vitro culture (IVC) procedures. The three natural steroidal alkaloids, cyclopamine, jervine and veratramine and the synthetic steroidal derivative of cyclopamine, cyclopamine-4-en-3-one, were added to IVM and IVC media at 12 μM. Oocytes were exposed to the toxins during maturation (IVM) and pre-implantation embryo during culture (IVC). Cleavage rates and embryo growth (morula and blastocyst production) and development through the hatched blastocyst stage were evaluated. Cyclopamine and cyclopamine-4-en-3-one inhibited cleavage rates and embryo growth and development of morulae and blastocysts in culture. Oocytes that were exposed to cyclopamine and cyclopamine-4-en-3-one during IVM only showed reduced cleavage rates and resulted in lower numbers of embryos that developed to the morula, blastocyst, and hatched blastocyst stages. The effects of these steroidal alkaloids on the oocyte during IVM and on the embryo during all stages of development up to and including the hatched blastocyst stage, demonstrates a dramatic cytotoxic effect on oocytes maturation and early pre-implantation embryos. This research also suggests that the Hedgehog signaling pathway may play a role in the maturing oocyte as well as the pre-implantation embryo. These in vitro fertilization techniques provide an economical, rapid through put and effective method to screen natural toxins, especially suspected reproductive toxins for cytotoxicity

An Evaluation of the Susceptibility of Goats to Larkspur Toxicosis

Larkspurs (Delphinium spp.) are a major cause of cattle losses in western North America, whereas sheep have been shown to be resistant to larkspur toxicosis. Goats are often used as a small ruminant model to study poisonous plants, even though they can be more resistant to some poisonous plants. It is not known how susceptible goats are to the adverse effects of larkspurs. In this study, we evaluated the susceptibility of goats to larkspur toxicosis by performing a dose-response study. We dosed goats with D. barbeyi collected near Cedar City, Utah at 3.3, 4.4, 6.6, 8.8 and 10.0 g plant material per kg body weight. None of the goats, at any of the doses, exhibited clinical signs typical of larkspur poisoning, including no observable muscle weakness. We conclude that goats are resistant to larkspur toxicosis, and thus it is very unlikely that goats would be poisoned by larkspur

North American Hard Yellow Liver Disease: An Old Problem Readdressed

Hard yellow liver disease or fatty cirrhosis periodically affects cattle, sheep, goats, pronghorn antelope (Antilocapra americana) and whitetail deer (Odocoileus virginianus texanus) within several Texas counties in the United States. Clinically it presents as chronic liver disease with progressive hepatic necrosis and fibrosis, icterus and liver failure. The damaged livers are yellow and many have multiple firm, often gritty foci that are scattered throughout all lobes. Early investigations included feeding studies using potential toxic plants, climate and forage studies, infectious disease surveys and various mycotoxin studies and analyses. None have definitively reproduced the disease or identified the inciting cause. However, the problem continues and recent outbreaks have allowed the collection of additional frozen tissues, and numerous paraffin tissue blocks and slides for additional studies. The objectives for this work are to evaluate and compare the microscopic changes, special histochemical studies, microbial and fungal surveys and chemical assays for dehyro-pyrrolizidine alkaloid (DHPA) metabolites of these additional cases with historical reports. These bovine livers had a spectrum of lesions including lipid degeneration and necrosis, eosinophilic granulomatous hepatitis, focal follicular lymphoid proliferation and chronic fibrosing hepatitis with dystrophic mineralization. No pyrrolizidine alkaloid metabolites were detected in any of the livers and select special stains did not reveal any fungal, bacterial or parasitic etiologies. The lack of findings and mixed histologic presentation suggest that this syndrome is a collection of chronic diseases probably of various etiologies. Earlier animal surveillance work is needed in endemic areas to better understand the etiology and pathogenesis of this syndrome

Landscape characterization and biodiversity research

Rapid deforestation often produces landscape-level changes in forest characteristics and structure, including area, distribution, and forest habitat types. Changes in landscape pattern through fragmentation or aggregation of natural habitats can alter patterns of abundance for single species and entire communities. Examples of single-species effects include increased predation along the forest edge, the decline in the number of species with poor dispersal mechanisms, and the spread of exotic species that have deleterious effects (e.g., gypsy moth). A decrease in the size and number of natural habitat patches increases the probability of local extirpation and loss of diversity of native species, whereas a decline in connectivity between habitat patches can negatively affect species persistence. Thus, there is empirical justification for managing entire landscapes, not just individual habitat types, in order to insure that native plant and animal diversity is maintained. A landscape is defined as an area composed of a mosaic of interacting ecosystems, or patches, with the heterogeneity among the patches significantly affecting biotic and abiotic processes in the landscape. Patches comprising a landscape are usually composed of discrete areas of relatively homogeneous environmental conditions and must be defined in terms of the organisms of interest. A large body of theoretical work in landscape ecology has provided a wealth of methods for quantifying spatial characteristics of landscapes. Recent advances in remote sensing and geographic information systems allow these methods to be applied over large areas. The objectives of this paper are to present a brief overview of common measures of landscape characteristics, to explore the new technology available for their calculation, to provide examples of their application, and to call attention to the need for collection of spatially-explicit field data