MAGNETIC RESONANCE IMAGING OF THE CANINE BRAIN AT 7 T

The purpose of this study was to describe relevant canine brain structures as seen on T2-weighted images following magnetic resonance (MR) imaging at 7 T and to compare the results with imaging at 1.5 T. Imaging was performed on five healthy laboratory beagle dogs using 1.5 and 7 T clinical scanners. At 1.5 T, spin echo images were acquired, while gradient echo images were acquired at 3 T. Image quality and conspicuity of anatomic structures were evaluated qualitatively by direct comparison of the images obtained from the two different magnetic fields. The signal-to-nose ratio (SNR) and contrast-to-noise ratio (CNR) were calculated and compared between 1.5 and 7 T. The T2-weighted images at 7 T provided good spatial and contrast resolution for the identification of clinically relevant brain anatomy; these images provided better delineation and conspicuity of the brain stem and cerebellar structures, which were difficult to unequivocally identify at 1.5 T. However, frontal and parietal lobe and the trigeminal nerve were difficult to identify at 7 T due to susceptibility artifact. The SNR and CNR of the images at 7 T were significantly increased up to 318% and 715% compared with the 1.5 T images. If some disadvantages of 7 T imaging, such as susceptibility artifacts, technical difficulties, and high cost, can be improved, 7 T clinical MR imaging could provide a good experimental and diagnostic tool for the evaluation of canine brain disorders.     

Public Education Financing Trends and the Gray Peril Hypothesis

The effects of migrating seniors on the provision of local public services in rural communities is growing in importance because of the large number of retiring baby boomers and the increasing rate at which these retirees are locating outside traditional retirement destinations. Some communities are optimistic about attracting and retaining retirees as an economic development strategy, but others are concerned that inmigrating seniors may be reluctant to support local public services, such as education, bringing with them “Gray Peril.” This article attempts to clarify questions regarding the Gray Peril hypothesis and local ability and willingness to fund education in Tennessee, an increasingly popular retirement destination. To this end, county per pupil education expenditure growth is explained by growth trends in local property tax assessment and sales tax revenue, and migration patterns of the retirement‐aged population from 1962 to 2002.     

Effects of warming, wetting and nitrogen addition on substrate-induced respiration and temperature sensitivity of heterotrophic respiration in a temperate forest soil

Soil heterotrophic respiration and its temperature sensitivity are affected by various climatic and environmental factors.However,little is known about the combined effects of concurrent climatic and environmental changes,such as climatic warming,changing precipitation regimes,and increasing nitrogen(N)deposition.Therefore,in this study,we investigated the individual and combined effects of warming,wetting,and N addition on soil heterotrophic respiration and temperature sensitivity.We incubated soils collected from a temperate forest in South Korea for 60 d at two temperature levels(15 and 20℃,representing the annual mean temperature of the study site and 5℃warming,respectively),three moisture levels(10%,28%,and 50%water-filled pore space(WFPS),representing dry,moist,and wet conditions,respectively),and two N levels(without N and with N addition equivalent to 50 kg N ha^-1year^-1).On day 30,soils were distributed across five different temperatures(10,15,20,25,and 30℃)for 24 h to determine short-term changes in temperature sensitivity(Q₁₀,change in respiration with 10℃increase in temperature)of soil heterotrophic respiration.After completing the incubation on day 60,we measured substrate-induced respiration(SIR)by adding six labile substrates to the three types of treatments.Wetting treatment(increase from 28%to 50%WFPS)reduced SIR by 40.8%(3.77 to 2.23μg CO₂-C g^-1h^-1),but warming(increase from 15 to 20℃)and N addition increased SIR by 47.7%(3.77 to 5.57μg CO₂-C g^-1h^-1)and 42.0%(3.77 to 5.35μg CO₂-C g^-1h^-1),respectively.A combination of any two treatments did not affect SIR,but the combination of three treatments reduced SIR by 42.4%(3.70 to 2.20μg CO₂-C g^-1h^-1).Wetting treatment increased Q₁₀by 25.0%(2.4 to 3.0).However,warming and N addition reduced Q₁₀by 37.5%(2.4 to 1.5)and 16.7%(2.4 to 2.0),respectively.Warming coupled with wetting did not significantly change Q₁₀,while warming coupled with N addition reduced Q₁₀by 33.3%(2.4 to 1.6).The combination of three treatments increased Q₁₀by 12.5%(2.4 to 2.7).Our results demonstrated that among the three factors,soil moisture is the most important one controlling SIR and Q₁₀.The results suggest that the effect of warming on SIR and Q₁₀can be modified significantly by rainfall variability and elevated N availability.Therefore,this study emphasizes that concurrent climatic and environmental changes,such as increasing rainfall variability and N deposition,should be considered when predicting changes induced by warming in soil respiration and its temperature sensitivity.     

Cytological characteristics of microconidia of <Emphasis Type="Italic">Magnaporthe oryzae</Emphasis>

The inner cellular structure of microconidia of Magnaporthe oryzae was examined using fluorescent probes and electron microscopic techniques. The volume of the nucleus relative to the cell was significantly larger in microconidia than in macroconidia or vegetative hyphae, similar to observations for spermatia of other fungi. Selective fluorescent staining revealed that cytosolic RNA was less abundant in microconidia than in macroconidia and germ tubes, suggesting that general metabolic activity in microconidia is low. Consistently, GFP expression driven by the TrpC promoter was highly active during the formation of phialides and microconidia but gradually decreased as the microconidia matured. Such data suggest that microconidia are in a quiescent or dormant state.     

Leiomyosarcoma of urinary bladder in a Shih Tzu dog

A 10-year-old intact male Shih Tzu dog presented with hematuria. Double-contrast cystography revealed a polypoid filling defect at the apex of the urinary bladder. Ultrasonography revealed a heterogeneously hypoechoic intramural mass with minimal vascular flow beneath the submucosal layer. After partial cystectomy, a well-demarcated bladder leiomyosarcoma was diagnosed on histopathology. The patient was alive and well without any clinical signs, recurrence, or metastasis at the 29-month follow-up after the surgical removal of the bladder mass. Leiomyosarcoma should be considered as a differential diagnosis if mass-like lesions are observed in the urinary bladder, although this type of malignancy is rare in canines. Histopathological confirmation is important for predicting prognosis and determining further medical plans.     

POSITRON EMISSION TOMOGRAPHY FEATURES OF CANINE NECROTIZING MENINGOENCEPHALITIS

A Yorkshire terrier and a Chihuahua were referred for acute onset, generalized tonic‐clonic seizures and were suspected to have meningoencephalitis based on magnetic resonance (MR) imaging findings. Brain lesions appeared hyperintense with T2‐weighted imaging and hypointense with T1‐weighted imaging, and were characteristic of necrotizing meningoencephalitis. Both dogs were diagnosed with necrotizing meningoencephalitis based on pathologic findings. Fluorine‐18 fluorodeoxyglucose positron emission tomography (FDG‐PET) was performed on both animals before euthanasia with the permission of the owner. In FDG‐PET images, these lesions seen in MR images were characterized by multifocal or diffuse hypometabolism. Our FDG‐PET results provided evidence of glucose hypometabolism in areas of necrosis and cavitation associated with necrotizing meningoencephalitis. FDG‐PET has the potential to provide valuable diagnostic information in dogs with suspected necrotizing encephalitis.     

Allelopathic potential of K21, selected as a promising allelopathic rice

The agronomic characteristics of a newly bred potent allelopathic rice, K21, including morphological appearance, resembled its female parent, Dongjinbyeo, except for 8 days' earlier heading and 9 cm shorter plant height. The water extract of K21 showed a greater inhibitory effect on the shoot and root growth of barnyardgrass than its female parent, but less than the male parent, Kouketsumochi. At the highest extract concentration of 5.0%, the inhibitory effect of K21 on the shoot growth of barnyardgrass was ≈ 64%, similar to its male parent. The dry weight of the barnyardgrass shoot was reduced by 13.0% when grown with K21 and 30.2% when grown with its male parent. There was no inhibitory effect on the shoot dry weight of barnyardgrass when grown with the female parent. The activity of cinnamic acid 4-hydroxylase in K21 was ≈ 1.8-fold higher than that of the female parent, but significantly lower than that of the male parent. The ρ-coumaric acid content in K21 was ≈ 60% higher than that of the female parent, but it was about half of the male parent. The total amount of phenolic compounds in K21 was ≈ 11.5% higher than in the female parent, but about half of the male parent. The results obtained suggest that the newly bred K21 contains desirable allelopathic traits derived from the male parent, Kouketsumochi, and acceptable agronomic traits from its female parent, Dongjinbyeo.     

Expression of adult plant resistance and its effect on the development of Puccinia striiformis f.sp. tritici in some Australian wheat cultivars

The onset of adult plant resistance (APR) to Puccinia striiformis was examined in seven Australian wheat cultivars under field conditions and in 14 cultivars under controlled environmental conditions. In most cultivars under field conditions the percentage leaf area affected by stripe rust at mid-tillering (GS 22–26; third leaf) was significantly less ( P < 0.05) than on the more susceptible cultivar Teal. The expression of APR was more conspicuous during tillering to node formation; at these growth stages chlorosis and/or necrosis developed in association with rust colonies on the most resistant cultivars. Under controlled conditions, the primary leaves of all cultivars except Olympic and Flinders displayed some resistance when compared with Teal (lower infection types, longer latent periods and/or less percentage leaf area affected). Studies on the spread of stripe rust from infection foci established in selected cultivars in the field indicated that the resistance detected at early growth stages in Suneca in controlled environmental studies also appeared to be effective in the field.