The bactericidal effect of N-acetyl-beta-D-glucosaminidase on bacteria.     

A M Hussain  R C Daniel  A J Frost 《Veterinary microbiology》1992,32(1):75-80

The bactericidal activity of N-acetyl-beta-D-glucosaminidase (NAGase) on some of the potential bacterial pathogens of the cow was determined. NAGase treatment significantly decreased the mean log10 number of Actinomyces pyogenes (P less than 0.01) and Staphylococcus aureus (P less than 0.05) after 2 and 4 hours of incubation at 37 degrees C. Similarly NAGase treatment significantly (P less than 0.05) reduced the mean log10 number of Streptococcus agalactiae and Pseudomonas aeruginosa after 4 hours incubation at 37 degrees C. NAGase did not reduce the numbers of Escherichia coli or Enterobacter aerogenes after either 2 or 4 hours incubation. Since NAGase and presumably other lysosomal enzymes are free on normal mucosal surfaces such as the uterus it is suggested that this direct bactericidal activity may be an important component of the normal defense mechanisms.  相似文献   

Studies on Some Aspects of Neutrophil Functions and Uterine Defenses in Cows during the Estrous Cycle     

A.M. Hussain  R.C.W. Daniel 《Reproduction in domestic animals》1991,26(6):290-296

Some aspects of the bovine uterine defense mechanisms were evaluated over two successive estrous cycles in five adult nonpregnant Friesian cows. Uterine flushings and blood samples were taken from each cow during the estrus and diestrus phases of each estrous cycle. A significant higher percentage of Candida albicans (C. albicans) were phagocytosed (P < 0.01) and killed (P < 0.05) by blood neutrophils during estrus than during diestrus. N-acetyl-β-D-glucosaminidase activity of uterine flushings, blood neutrophil alkaline phosphatase activity scores, and serum progesterone concentrations during diestrus increased significantly (P < 0.01) compared to those at estrus. Mean total blood leucocyte and monocyte counts increased significantly (P < 0.05) during estrus compared to diestrus .
It is concluded, that the different hormonal status has at each stage of the estrous cycle a definite effect on uterine resistance against bacterial infection and a fall in serum progesterone concentrations is associated with an increased ability of blood neutrophils to phagocytose and kill C. albicans .  相似文献   

Letters to the Editor     

Daniel J. Mack  Gordon H. Theilen 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1989,3(3):190-190

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Development of a carbon-heat hybrid ethylene scrubber for fresh horticultural produce storage purposes     

Domingo Martínez-Romero  Fabián Guillén  Salvador Castillo  Pedro Javier Zapata  María Serrano  Daniel Valero 《Postharvest Biology and Technology》2009,51(2):200-205

A scrubber to remove ethylene continuously from stored environments was developed. The device comprised a cartridge heater tightly joined to the activated carbon–1% Pd. The application of heat pulses led to an increase in ethylene oxidation and to auto-regeneration of the activated carbon. The efficacy of ethylene removal was higher with the number of heat pulses. Several combinations of exogenous ethylene concentrations and heater core temperatures (100–325 °C) of the device were assayed to determine their effectiveness in removing ethylene from the storage area. The results indicated that increasing the heater temperature led to enhanced percentages of eliminated ethylene but also increased CO₂ concentrations. This CO₂ could come from the activated carbon due to its breakthrough. Thus, temperatures ranging between 150 and 200 °C eliminated 96–99% of ethylene, with low CO₂ accumulation (0.10–0.18 kPa) and without affecting the temperature of the storage environment. Thus, this device might be a promising tool for scrubbing ethylene from storage areas for fresh horticultural produce in which ethylene can induce detrimental effects.  相似文献   

Microvascular Free Tissue Transfer of the Rectus Abdominis Muscle in Dogs     

Earl F. Calfee III  DVM  Otto I. Lanz  DVM  Diplomate ACVS    Daniel A. Degner  DVM  Diplomate ACVS    Steven L. Peterson  DVM  MS  MD  Diplomate ACVS    Robert B. Duncan  DVM  PhD  Diplomate ACVP    Richard V. Broadstone  DVM  PhD  Diplomate ACVA    Robert A. Martin  DVM  Diplomate ACVS  ABVP    Brenda Austin  BS 《Veterinary surgery : VS》2002,31(1):32-43

OBJECTIVE: To assess donor-site morbidity and survival of the rectus abdominis muscle with an overlying skin graft after free tissue transfer to a medial femorotibial defect in dogs. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Phase 1: 6 canine cadavers; phase 2: 7 adult mixed-breed dogs. METHODS: Phase 1: The rectus abdominis muscle was removed from canine cadavers, muscular and vascular dimensions were recorded, and angiography was performed. Phase 2: Muscular transfer was performed through anastomosis of the caudal epigastric artery and vein to the saphenous artery and medial saphenous vein. Transferred tissues were evaluated on postoperative days 3, 6, 10, and 13. Animals were examined daily until euthanasia between postoperative days 31 and 42. Postmortem angiograms were performed and tissues collected for histopathologic evaluation. RESULTS: Phase 1: Appropriate vascular dimensions for microvascular anastomosis were confirmed and surgical technique perfected. Phase 2: Muscular excision produced minimal donor-site morbidity. All muscles survived after microvascular transfer and angiography confirmed vascular patency. All of the skin grafts survived, with one graft undergoing partial necrosis. CONCLUSIONS: The rectus abdominis muscle can be successfully transferred to a medial femorotibial defect and can serve as a bed for acute skin grafting. No significant donor-site morbidity is associated with its removal. CLINICAL RELEVANCE: Microvascular free tissue transfer of the canine rectus abdominis muscle has not been previously described. This technique provides a new alternative for repair of appropriate wounds. Additional studies are needed to define its utility in clinical patients.  相似文献   

Impacts of hypersaline water on the biotransformation and toxicity of fenthion on rainbow trout (Oncorhynchus mykiss), striped bass (Morone saxatilis X Morone chrysops) and tilapia (Oreochromis mossambicus)     

Ola Bawardi  Daniel Schlenk 《Pesticide biochemistry and physiology》2007,88(3):321-327

Hypersaline water derived from agricultural practices primarily in arid landscapes can impact fisheries in streams receiving run-off from fields. Previous studies have indicated significant elevation in the toxicity of thio-ether pesticides by hypersaline water in certain species of euryhaline fish due to enhanced formation of sulfoxide metabolites which may be more toxic than the parent compounds. The objectives of this study were to evaluate the effects of salinity on the toxicity of the thio-ether organophosphate pesticide, fenthion in three species of euryhaline fish: rainbow trout (Oncorhynchus mykiss), striped bass (Morone saxatilis X Morone chrysops), tilapia (Oreochromis mossambicus) and determine whether a relationship was observed between toxicity and enantioselective sulfoxidation. Stereochemical formation and total sulfoxide formation did not mirror acute toxicity in the three species exposed in fresh or hypersaline conditions. Mortality of striped bass and rainbow trout due to fenthion exposure was enhanced by hypersaline treatments and a trend towards increased toxicity was observed in tilapia. In liver microsomes of rainbow trout, inhibition of cytochrome P450 (CYP) caused a respective 7- and 3-fold increase in sulfoxide formation in liver microsomes fresh and saltwater fish, and a significant increase in the formation of the (+)R-sulfoxide. CYP inhibition also caused a significant elevation of the (+)R-sulfoxide in freshwater striped bass, but not in hypersaline-treated bass. The results indicated contribution by CYP in the sulfoxidation of fenthion as well as the formation of other metabolites in all three species. In summary, hypersaline conditions impacted fenthion toxicity under conditions that appeared to be independent of fenthion sulfoxide formation indicating a much more complex mechanism of action for compounds with phosphorothioate and thio-ether structural features potentially involving multiple oxidative pathways.  相似文献   

The shared landscape: what does aesthetics have to do with ecology?   总被引：4，自引：0，他引：4  

Paul H. Gobster  Joan I. Nassauer  Terry C. Daniel  Gary Fry 《Landscape Ecology》2007,22(7):959-972

This collaborative essay grows out of a debate about the relationship between aesthetics and ecology and the possibility of an “ecological aesthetic” that affects landscape planning, design, and management. We describe our common understandings and unresolved questions about this relationship, including the importance of aesthetics in understanding and affecting landscape change and the ways in which aesthetics and ecology may have either complementary or contradictory implications for a landscape. To help understand these issues, we first outline a conceptual model of the aesthetics–ecology relationship. We posit that: 1. While human and environmental phenomena occur at widely varying scales, humans engage with environmental phenomena at a particular scale: that of human experience of our landscape surroundings. That is the human “perceptible realm.” 2. Interactions within this realm give rise to aesthetic experiences, which can lead to changes affecting humans and the landscape, and thus ecosystems. 3. Context affects aesthetic experience of landscapes. Context includes both effects of different landscape types (wild, agricultural, cultural, and metropolitan landscapes) and effects of different personal–social situational activities or concerns. We argue that some contexts elicit aesthetic experiences that have traditionally been called “scenic beauty,” while other contexts elicit different aesthetic experiences, such as perceived care, attachment, and identity. Last, we discuss how interventions through landscape planning, design, and management; or through enhanced knowledge might establish desirable relationships between aesthetics and ecology, and we examine the controversial characteristics of such ecological aesthetics. While these interventions may help sustain beneficial landscape patterns and practices, they are inherently normative, and we consider their ethical implications.  相似文献   

Cerebellar degeneration in cattle grazing Solanum bonariense ("Naranjillo") in Western Uruguay.     

José Manuel Verdes  Antonio Mora?a  Fernando Gutiérrez  Daniel Battes  Luis Eusebio Fidalgo  Florentina Guerrero 《Journal of veterinary diagnostic investigation》2006,18(3):299-303

Cattle in western Uruguay that were eating Solanum bonariense developed periodic episodes of ataxia, hypermetria, hyperesthesia, head and thoracic limb extension, opisthotonus, nystagmus, and falling to the side or backward. Similar clinical signs were experimentally reproduced in cattle by administration of S. bonariense via rumen cannula at a dose of 1,024 g/kg body mass. No significant gross lesions were observed in field cases or experimentally induced cases. Spontaneous and induced histologic lesions were similar and included vacuolation, degeneration, and loss of Purkinje cells. Axonal spheroids, microcavitations, and other changes of wallerian-type degeneration in cerebellar white matter were also observed. Ultrastructural changes included increased number of electron-dense residual storage bodies in membrane-bound vesicles in affected Purkinje cells, and similar vesicles and mitochondria in axonal spheroids. No histologic lesions were detected in the other examined tissues. The Purkinje-cell swelling and vacuolation with subsequent cerebellar degeneration are suggestive of Purkinje-cell specific toxin that produces abnormal lysosome function and cell specific axonal transport. This is the first report of S. bonariense toxicity.  相似文献   

Medical and surgical management of traumatic elbow luxation in a juvenile ferret.     

Bernadette A Hermann  Keryn L Plensdorf  Daniel A Degner 《Veterinary Clinics of North America: Exotic Animal Practice》2006,9(3):651-655

Elbow luxation is a common orthopedic injury in the ferret. The injury is usually caused by trauma but can also occur spontaneously. The most successful treatment involves a combination of surgical and medical intervention. Surgical treatment includes open reduction of the elbow joint and stabilization with orthopedic implants. Medical treatment includes external coaptation, analgesia, and prevention of infection. Owner compliance also plays an important role in return to full function of the luxated ferret elbow joint.  相似文献   

In vitro heterogeneity of osteogenic cell populations at various equine skeletal sites          下载免费PDF全文

Laurie A. McDuffee  Gail I. Anderson  Glenda M. Wright    Daniel A.J. Ryan 《Canadian journal of veterinary research》2006,70(4):277-284

Bone cell cultures were evaluated to determine if osteogenic cell populations at different skeletal sites in the horse are heterogeneous. Osteogenic cells were isolated from cortical and cancellous bone in vitro by an explant culture method. Subcultured cells were induced to differentiate into bone-forming osteoblasts. The osteoblast phenotype was confirmed by immunohistochemical testing for osteocalcin and substantiated by positive staining of cells for alkaline phosphatase and the matrix materials collagen and glycosaminoglycans. Bone nodules were stained by the von Kossa method and counted. The numbers of nodules produced from osteogenic cells harvested from different skeletal sites were compared with the use of a mixed linear model. On average, cortical bone sites yielded significantly greater numbers of nodules than did cancellous bone sites. Between cortical bone sites, there was no significant difference in nodule numbers. Among cancellous sites, the radial cancellous bone yielded significantly more nodules than did the tibial cancellous bone. Among appendicular skeletal sites, tibial metaphyseal bone yielded significantly fewer nodules than did all other long bone sites. This study detected evidence of heterogeneity of equine osteogenic cell populations at various skeletal sites. Further characterization of the dissimilarities is warranted to determine the potential role heterogeneity plays in differential rates of fracture healing between skeletal sites.  相似文献