Postnatal development of canine axial globe length measured by B-scan ultrasonography

OBJECTIVE: The objectives of this study were to document the development of axial globe length (AGL) in normal mesocephalic cross-bred dogs between 2 and 52 weeks of age, to determine a relationship between AGL and age, and derive an equation to predict AGL in normal mesocephalic cross-bred dogs. ANIMALS STUDIED AND PROCEDURE: The AGL of twenty normal mesocephalic cross-bred dogs was measured at 12 time points from 2 to 52 weeks of age using B-scan ultrasonography. RESULTS: The mean (+/- SEM) AGL increased from 12.65 mm (+/- 0.18) at 2 weeks of age to 19.52 mm (+/- 0.18) at 52 weeks of age. The correlation between AGL and age was evaluated by fitting possible variables to a regression pattern. A linear model of natural logarithmic-transformed value of AGL (mm) and age (week) was established. Side (left or right eye) and gender did not correlate with development of AGL. CONCLUSIONS: A reverse transformation of the formula can be used to predict AGL in mesocephalic cross-bred dogs: AGL = 10.847 * age in weeks 0.1653.     

畜产品安全与毒害物质残留研究进展

论述了畜产品安全及其目前畜产品中的兽药、激素、重金属、生物毒素、农药、微生物等毒害物质的残留，并对畜产品安全现状及存在的问题进行了分析。     

恩拉霉素的研究进展

概述了恩拉霉素的理化特性、药效学、毒理学和临床应用研究进展,展望了今后恩拉霉素的研究方向.     

Reproductive Strategies and the Co-occurrence of Climax Tree Species

In a central New Hampshire forest, three co-occurring tree species were found to occupy different positions on a reproductive strategy gradient. These reproductive strategy differences, in part, described separate niches for the species. The three-species complex is hypothesized to form a dynamic climax overstory characterized by cyclical replacement of one dominant species by another.     

Morphological and Apoptotic Comparison of Primordial and Primary Follicles in Cryopreserved Human Ovarian Tissue

There are few reports which were designed to compare the survival rate of human primary follicles with primordial follicles after cryopreservation. This study was designed to evaluate whether such a difference occurs. Human ovarian biopsies were cryopreserved using dimethylsulphoxide/sucrose as the cryoprotectants. Fresh and cryopreserved ovarian samples were evaluated for viability differences between the two types of follicles using the endpoints of histology, ultrastructure and DNA fragmentation. In comparison with fresh ovarian tissue (83.9% ± 10.0%), the percentage of morphologically normal primordial follicles was not significantly different in cryopreserved tissue (73.9% ± 17.2%). However, a lower percentage of primary follicles with normal morphology was seen in the cryopreserved group (43.3% ± 25.7% vs 74.8% ± 19.4% for the fresh group). Transmission electron microscopy revealed that the cryopreservation did not appear to affect the structural integrity of primordial follicles; however, varying ultrastructural damage to the cytoplasm was observed in the majority of the cryopreserved primary follicles. Using a DNA fragmentation assay, the percentage of apoptotic primordial and primary follicles in the unfrozen (26.3% and 20%) and frozen (23.3% and 25%) ovarian tissue was similar. A higher proportion of primary follicles, compared to primordial follicles, suffer histological damage after slow freezing.     

Assessment of the dark-adaptation time required for recovery of electroretinographic responses in dogs after fundus photography and indirect ophthalmoscopy

OBJECTIVE: To investigate the duration of dark-adaptation time required for recovery of electroretinographic responses after fundus photography or indirect ophthalmoscopy in dogs. ANIMALS: 6 dogs. PROCEDURE: Initially, scotopic-intensity series of electroretinograms (ERGs) were recorded after 20 minutes of dark adaptation. The fundus of the left eye of each dog was photographed (n = 10) or examined via indirect ophthalmoscopy for 5 minutes with moderate- (117 candela [cd]/m2) or bright-intensity (1,693 cd/m2) light; ERGs were repeated after a further 20 or 60 minutes of dark adaptation (6 procedures/dog). RESULTS: Following 20 minutes of dark adaptation after fundus photography, the b- and a-wave amplitudes were reduced in response to brighter stimuli, compared with pretest ERGs; after 60 minutes of dark adaptation, ERG amplitudes had recovered. Following 20 minutes of dark adaptation after indirect ophthalmoscopy (moderate-intensity light), significantly lower b-wave amplitudes were recorded in response to 2 of the brighter flash stimuli, compared with pretest ERGs; after 60 minutes of dark adaptation, ERG amplitudes had recovered. Following 20 minutes of dark adaptation after indirect ophthalmoscopy (bright-intensity light), all ERG amplitudes were significantly decreased and implicit times were significantly decreased at several flash intensities, compared with pretest ERGs; after 60 minutes of dark adaptation, ERG amplitudes and implicit times had returned to initial values, except for b-wave amplitudes recorded in response to dimmer stimuli. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that at least 60 minutes of dark adaptation should be allowed before ERGs are performed in dogs after fundus photography or indirect ophthalmoscopy.