猪肺炎霉形体及其膜致细胞病变的研究

采用培养的兔肾原代单层细胞，接种猪肺炎霉形体及其膜部分，观察其致细胞病变情况，当霉形体接种量为５～１５μｇ／ｍｌ菌体蛋白时，无细胞病变作用，而接种量为２０～３０μｇ／ｍｌ菌体蛋白时，均有致细胞病变作用；当霉形体膜接种量为５～２５μｇ／ｍｌ膜蛋白时，无细胞病变作用，接种量达３０～５０μｇ／ｍｌ膜蛋白时，均可使细胞病变。随着接种量的加大和作用时间的延长，致细胞病变的程度增强。     

ACQUIRED URETEROVAGINAL FISTULA SECONDARY TO OVARIOHYSTERECTOMY IN A DOG: DIAGNOSIS USING ULTRASOUND-GUIDED NEPHROPYELOCENTESIS AND ANTEGRADE URETEROGRAPHY

A one year old Jack Russel terrier became urinary incontinent one week after elective ovariohysterectomy. Intravenous urography and cystourethrography showed right hydronephrosis but failed to demonstrate the cause of incontinence. Nephropyelocentesis under ultrasound guidance produced exudate and subsequent antegrade ureterography demonstrated a ureterovaginal fistula. Exploratory laparotomy confirmed this diagnosis and indicated that the ureter had been included in a ligature around the vaginal stump. This is an uncommon complication of ovariohysterectomy.     

Renal corpuscle development in boreal fishes with and without antifreezes

Light and election microscopy were used to document the degree of renal corpuscle development in boreal telcost fishes that produce peptide or glycopeptide antifreeze compounds on a seasonal or permanent basis. Emphasis was placed on gadids, cottids and pleuronectids from both the North Atlantic and North Pacific Oceans. Based on the classification of Marshall and Smith (1930), corpuscle development ranged from fully glomerular (Type 1) to pauciglomerular (Type III). Unlike the situation in Antarctic notothenioid fishes, there were no aglomerular species among the boreal fishes. Corpuscles were small in diameter in gadids whereas in cottids they ranged from small to large with considerable intraspecific variation. Eight of eleven species with antifreeze had intermediate (Type II–III) or pauciglomerular kidneys with relatively few dense corpuscles (dia. 36–82m). In some of these species an extensive mesangium and a substantial capillary endothelium contributed to a glomerular filtration barrier that was four to five times thicker than that in Type I kidneys. The corpuscles of other pauciglomerular species were unremarkable and appeared functional at the ultrastructural level. The boreal fish fauna is taxonomically diverse and, compared to the unrelated Antarctic fauna, of relatively recent evolutionary origin. Furthermore, antifreeze is present only during the winter in some species. Hence it is not surprising that the urinary conservation of antifreeze is accomplished by mechanisms other than the evolutionary loss of renal corpuscles.     

Regulation of Renal Hemodynamics and the Nitric Oxide-Arginine Pathway

Over the past ten years, nitric oxide has been shown to be important in a number of biological systems. This article is a review of the literature on nitric oxide and its affects on hemodynamics in the kidney. Nitric oxide is a major contributor to basal vasodilatory tone in the renal vasculature and systemic vasculature. It also has effects on the mechanisms which comprise the tubuloglomerular feedback loop. (Vet Emerg & Crit Care, 1998; 8: 7–18)     

枣铁皮病病原鉴定

 枣铁皮病主要为害大枣果实,可导致果实腐烂和提早落果,据症状特点可分为铁皮型和缩果型2种类型。1993~1995年对河北和河南2省6个不同枣区大枣铁皮病病果进行分离、接种和再分离,证实枣铁皮病病原为:链格孢Alternaria alternata(Fr.) Keissler;实腐茎点霉Phoma destructiva Plowr,壳梭孢属一种真菌Fusicoccum sp.3种病原真菌可以单独或混合侵染。     

Effects of serial ultrasound-guided renal biopsies on kidneys of healthy adolescent dogs

Ten healthy mixed-breed dogs were used to evaluate the functional and structural effects of serial ultrasound-guided renal biopsies obtained with an automated biopsy needle. In each dog, one lateral renal cortex was biopsied at 2, 4, and 6 months of age; the other kidney was the control. Five dogs had two tissue cores and five dogs had four tissue cores taken on each biopsy occasion, and one core was examined microscopically. One week before each biopsy and a month after the final biopsy, the glomerular filtration rate (GFR) was determined by renal scintigraphy. Dogs were then euthanized for evaluation of gross and microscopic lesions attributable to the biopsies. There was no difference between GFR values for biopsied kidneys and those of control kidneys ( P >0.05). Microscopic lesions were not identified in biopsies taken at 2 and 4 months, but focal lesions were found in three of 10 specimens taken at 6 months of age. At necropsy, six of 10 biopsied kidneys had small visible capsular scars, and linear tracts <2 mm wide were observed on cut surfaces in six of 10 biopsied kidneys cut transversely into slices 5 mm thick. Discrete light microscopic lesions were observed in 25 of 452 (5.5%) of randomly selected 6-mm-diameter sections of renal cortex from biopsied kidneys. We conclude that serial renal cortical biopsies can be obtained by our method from healthy adolescent dogs with minimal risk of inducing changes that might be confused with those of a progressive renal disease.     

Influence of estrogen on acetylcholinesterase activity in primary cultures of cerebral cells from neonatal rats

To estimate the influence of estrogen on the functional development of the central nervous system during the neonatal period, several doses of estradiol‐17β (E₂) were treated to cultured cells from the cerebral cortex of neonatal rats and the acetylcholinesterase (AChE) activity was examined. E₂ was added to give the following final concentrations: 0, 10^?10, 10^?9, and 10^?8 M. After 72 h of incubation, all cells were obtained from dishes to determine the AChE activity. Although apparent morphological changes were not observed among treatments cultured for 72 h, E₂ suppressed dose‐dependently the spontaneous increase of AChE activity in cerebral cells. Furthermore, a single dose of tamoxifen, an E₂ receptor binding molecule with agonist and antagonist properties, also acted in a similar manner as E₂. These findings suggest that the functional development of the cerebral cortex, at least the cholinergic system, during the neonatal period is regulated by E₂.     

Effect of tillage, cover crop and crop rotation on the composition of weed flora in a sandy soil

The development of integrated weed management strategies requires knowledge of mechanisms that influence compositional changes in weed flora. A 9-year study was initiated in 1988 at Delhi, Canada, on a loamy sand soil to evaluate the effect of tillage systems [conventional (CT) and no-till (NT)] and cover crops (only in NT) on weed density, species composition and associations, and crop yield in a winter wheat ( Triticum aestivum L.)/bean/winter wheat rotation. Three bean types: soyabean ( Glycine max L. Merr.), white bean ( Phaseolus vulgaris L.) and kidney bean ( P . vulgaris L.) were included. The NT system included variations: rye ( Secale cereale L.) or maize ( Zea mays L.) cover crop, volunteer wheat disked after harvest and wheat stubble. Data were collected in 1994, 1995 and 1996. Tillage systems, cover crops and crop type had differential effects on weed densities, species composition and associations. Weed densities were not affected by tillage or cover crops in wheat but, in the beans, densities were greater in the CT than in the NT systems. Various associations of weed species with tillage system, cover crop and crop type were observed. Crop yields were not affected by tillage type or cover crop, except that soyabean yields were highest in plots with cover crops.     

四季豆枯萎病病原鉴定及防治

从南宁市郊11个病区采集的四季豆枯萎病株标样,经分离培养鉴定和致病性测定,证明其病原菌为尖孢镰刀菌菜豆专化型(Fusarium oxysporum f.sp.phaseoli Kend & Syd)。此病在南宁于4月上中旬四季豆初花期开始发生,5月中下旬盛花至结荚期为发病高峰期。用滤纸碟法进行药效试验的结果,40%灭病威300—500倍液的抑菌圈最大,田间灌根防治也有一定效果。可用种子重量的0.5%多菌灵可湿性粉拌种。品种间抗病性有显著差异,秋抗19号和秋抗6号较抗病。     

氧化应激在硝基苯致小鼠肾损伤中的作用

为探讨硝基苯对小鼠肾的毒性作用，采用灌胃法对试验小鼠用硝基苯进行染毒，染毒剂量分别为26、52、105mg／kg，每天染毒1次，共30d。于末次染毒后第2d将小鼠脱颈处死，立即取出肾通过相应处理用于抗氧化指标检测及显微和超微结构的观察。结果，染毒小鼠主要表现为近曲小管上皮细胞不同程度水样变性，线粒体肿胀，脊断裂；内质网脱核糖颗粒；细胞核发生形变；肾小球血管内皮细胞肿胀，血管扩张；随着染毒剂量的加大，肾和血清中MDA含量逐渐升高，SOD和GSH—Px酶活性不断降低，与对照组比较，均差异显著（P〈0．05）或极显著（P〈0．01）。结果表明，硝基苯能够诱发小鼠肾细胞发生氧化胁迫，并诱导细胞凋亡的发生。