Effect of disposition on the relative delayed neurotoxicity potency among leptophos analogs

The oxons of leptophos, its desbromo analog, and its ethoxy analog all inhibit hen brain neurotoxic esterase (NTE) to a similar degree in vitro, but have large differences in minimum effective oral doses for organophosphorus-induced delayed neurotoxicity. The potencies of leptophos and ethoxyleptophos are increased 10-fold when administered to hens intravenously (iv), but the potency of desbromoleptophos is nearly the same whether administered iv or po. Leptophos distributes nearly five times more rapidly from the central compartment than does desbromoleptophos, and its attenuated oral potency may be due to slower net absorption and/or dilution by compartments other than nervous tissue. Intravenously administered phenylphosphonothionates are excreted rapidly into the gastrointestinal tract and a large proportion of the dose is eliminated in the first 48 hr. Indirect evidence indicates that ethoxyleptophos is more rapidly degraded and ethoxyleptophos-inhibited NTE recovers more rapidly than does NTE inhibited by leptophos or desbromomleptophos. It is proposed that differential aging of ethoxyleptophos chiral isomers as well as pharmacokinetic factors may contribute to the apparently anomalous behavior of these three analogs.     

Relationship of blood corticosterone, immunoglobulin and haematological values in young crocodiles (Crocodylus porosus) to water temperature, clutch of origin and body weight

Objective To examine whether sub-optimal temperature induced stress and immunosuppression in farmed saltwater crocodile (Crocodylus porosus) hatchlings. Design A clinico-pathological study. Animals A total of 140 hatchlings were used. Procedure Body weight and length, plasma corticosterone and immunoglobulin concentrations and total and differential white blood cell counts were measured in 140 hatchlings from five clutches divided between five water temperature treatment groups. Initially all groups were housed at 32°C for 10 weeks, then two groups (L, LC) were changed to low temperature (28°C) and two groups (H, HC) to high temperature (36°C), while one group (C) remained at 32°C. The LC and HC groups were maintained at these temperatures for 10 days, after which the water temperature of both groups was returned to 32°C. Blood samples were collected twice (at 6 and 9 weeks of age) before the initial temperature change, and at 10 days and 4 weeks after the initial temperature change (at 11.5 and 14 weeks of age). Results Except for an increase in plasma corticosterone in the HC group and a decrease in the L group when the temperature change was first introduced, changes in plasma corticosterone were not significant. There were no significant changes in immunoglobulin concentrations. There were, however, significant decreases in the total white cell and lymphocyte counts in the LC group after the temperature was decreased to 28°C, and an increase in these counts after water temperature was returned to 32°C. Clutch of origin had significant effects on body weight and length gains, and there were negative relationships between body weight and corticosterone concentrations and between body weight and immunoglobulin concentrations. Conclusions As haematological changes indicative of stress were not associated with significant changes in serum corticosterone, immunosuppression in young crocodiles may be independent of the hypothalamic-pituitary-adrenal cortical axis.     

Differences between Brahman and Holstein cows in heat-shock induced alterations of protein synthesis and secretion by oviducts and uterine endometrium

Our objectives were to test differences in protein synthesis and secretion by cultured oviducts and endometrium from Brahman and Holstein cows and the response of those tissues to in vitro heat shock. Explants of oviductal tissue obtained at estrus from Holstein (n = 5) and Brahman (n = 6) cows were cultured at a homeothermic (39 degrees C) or heat shock (43 degrees C) temperature. At 6 h, cultures were pulse-chase labeled (2 h, L[4,5-3H]leucine; 2 h, L-leucine). Endometrial explants were cultured similarly except that pulse labeling was performed for the first 0 to 15, 0 to 30, 30 to 60 and 60 to 90 min following onset of heat shock. A temperature of 43 degrees C increased secretion of nondialyzable 3H-labeled macromolecules by both oviducts of Brahmans but depressed secretion by the oviduct ipsilateral to the side of ovulation of Holsteins. For both breeds, 43 degrees C decreased incorporation of [3H]leucine into trichloroacetic acid (TCA)-precipitable radioactivity in oviducts from the ipsilateral side. Secretion of 3H-labeled macromolecules by pulse-labeled endometrial explants increased at 43 degrees C. Heat shock caused an immediate increase in TCA-precipitable radioactivity in tissue during pulse labeling for Holstein tissues. Incorporation was decreased at 43 degrees C in tissue from Brahmans in the first 30 min and increased thereafter. Incorporation of [3H]thymidine by endometrial explants from Brahmans was increased at 43 degrees C, whereas it was suppressed at 43 degrees C in explants from Holstein cows. Heat shock proteins of 72,000 and 90,000 molecular weight were present in endometrial tissues. A major secretory product of endometrium had a molecular weight of 57,500 for Brahmans and a lower molecular weight (55,600) for Holsteins.     

Genital pathology of feral male goats

Genitalia from 1000 feral male goats derived from western Queensland and New South Wales were examined after slaughter at an abattoir and the prevalence of abnormalities determined. Ulcerative balanoposthitis, considered due to caprine herpesvirus infection, was observed in 11 animals (1.1%); acidophilic intranuclear inclusions were found in 7 of these. Other conditions included focal hypoplasia of seminiferous tubules in 2 bucks (0.2%), segmental aplasia of the epididymis (one buck, 0.1%), bulbourethral gland cysts with contained aggregations (33 bucks, 3.3%) and haemangiosarcoma of the bulbourethral gland in one animal. The low prevalence of several conditions such as spermatic granuloma, cryptorchidism, and testicular hypoplasia, was attributed largely to the fact that the bucks examined were horned so that the recognised association between genital abnormalities and polledness did not apply.     

Influence of gibberellic acid and stock plant irradiance on carbohydrate content and rooting in cuttings of Scots pine seedlings (Pinus sylvestris L.)

Seedlings of Pinus sylvestris L. were grown at three different irradiances (12, 30, or 60 W m(-2)) under a 17 h photoperiod. After six weeks, cuttings were excised and rooted at 30 W m(-2). Gibberellic acid (GA(3), 5 microl of 2 x 10(-4) or 2 x 10(-3) M) was applied to each cutting immediately after excision. Cuttings from stock plants grown at the low irradiance rooted most quickly, whereas the highest number of roots per cutting was obtained in cuttings from stock plants grown at 30 W m(-2). Gibberellic acid delayed rooting and reduced the number of roots in cuttings from stock plants grown at 12, 30, or 60 W m(-2). The initial carbohydrate content of cuttings increased with stock plant irradiance. For all carbohydrates, except myoinositol and an unknown inositol derivative, the content per cutting increased during the first 28 days of rooting. The GA(3) treatment significantly reduced the starch content of cuttings during the rooting period, but did not significantly change the content of ethanol soluble carbohydrates.     

Phytophthora cambivora in Oregon and its pathogenicity to Chrysolepis chrysophylla

A new canker disease causing mortality of golden chinquapin trees [Chrysolepis chrysophylla (Dougl.) Hjelmqvist], in Oregon was recently observed. Most of the symptomatic or dead trees were located near roads. The cankers on the lower boles of trees are similar to those caused by species of Phytophthora on other trees in western North America. The cankers in the inner bark were reddish‐orange in colour and extended upward from necrotic roots. Phytophthora cambivora (Petri) Buisman was isolated from the cankers; identity was confirmed by morphological comparison with known isolates and internal transcribed spacer sequence analysis. Pathogenicity was confirmed by inoculation of chinquapin seedlings and mature trees. Seven of nine isolates from chinquapin were A2 mating type; 27 of 28 isolates from other hosts in Oregon and Washington were A1 mating type.     

INTER‐ AND INTRAFRACTION MOTION FOR STEREOTACTIC RADIOSURGERY IN DOGS AND CATS USING A MODIFIED BRAINLAB FRAMELESS STEREOTACTIC MASK SYSTEM

Precise and accurate patient positioning is necessary when doing stereotactic radiosurgery (SRS) to ensure adequate dosing to the tumor and sparing of normal tissues. This prospective cross‐sectional study aimed to assess feasibility of a commercially available modified frameless SRS positioning system for use in veterinary radiotherapy patients with brain tumors. Fifty‐one dogs and 12 cats were enrolled. Baseline and verification CT images were acquired. The verification CT images from 32 dogs and five cats had sufficient images for fusion to baseline CT images. A rigid box‐based fusion was performed to determine interfraction motion. Forty‐eight dogs and 11 cats were assessed for intrafraction motion by cine CT. Seventy percent of dogs and 60% of cats had interfraction 3D vector translational shifts >1 mm, with mean values of 1.9 mm in dogs, and 1.8 mm in cats. In dogs muscle wasting was weakly correlated with translational shifts. The maximum angular interfraction motion observed was 6.3° (roll), 3.5° (pitch), and 3.3° (yaw). There was no correlation between angular interfraction motion and weight, brachycephaly, or muscle wasting. Fifty‐seven percent of dogs and 50% of cats had respiration‐related intrafraction motion. Of these, 4.5% of dogs and 10% of cats had intrafraction motion >1 mm. This study demonstrates the modified Brainlab system is feasible for SRS in dogs and cats. The smaller cranial size and difference in anatomy increases setup uncertainty in some animals beyond limits usually accepted in SRS. Image‐guided positioning is recommended to achieve clinically acceptable setup accuracy (<1 mm) for SRS.     

Genetic variation in dieback resistance in Fraxinus excelsior confirmed by progeny inoculation assay

Ash dieback caused by the pathogenic fungus Hymenoscyphus fraxineus [previously known as H. pseudoalbidus (sexual stage) and Chalara fraxinea (asexual stage)] is a widespread problem in Europe. Here, we assess crown damage from natural infection and necrosis development following artificial controlled inoculations on full‐sib and half‐sib progeny from Danish Fraxinus excelsior clones with contrasting and well‐characterized levels of susceptibility to the disease. The inoculation assay was performed on a total of 123 offspring, and necrosis development monitored over two years. The offspring from low susceptible mother clones developed smaller necroses when compared to offspring from susceptible clones. Their crown damage due to natural infections was also significantly less. The correlation coefficient between average crown damages of mother clones and the average of their progeny was 0.85 (natural infections), while the correlation between crown damage of mother clones and the average necrosis development in their progeny after controlled inoculation was 0.73. The correlation between resistance of parent trees and crown damage/necrosis development on their offspring confirms the presence of heritable resistance and indicates that a bioassay based on controlled inoculations has the potential of becoming a fast and cost‐effective tool for estimation of dieback susceptibility in breeding programmes for resistance in ash trees.