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61.
A 13-year-old cocker spaniel presented with pain on opening the mouth. History of a previous left total ear canal ablation with lateral bulla osteotomy, left intermittent facial palsy and left intermittent head tilt suggested progression of a total ear canal ablation with lateral bulla osteotomy complication. Magnetic resonance imaging revealed a large mass arising from the tympanic bulla. Cytology of aspirates revealed a chronic suppurative inflammatory reaction and numerous cholesterol crystals. The mass was removed by surgical excision and an active drainage system was placed for a few days. The head tilt, facial palsy and apparent pain were resolved by the surgery. Physical examination was unremarkable nine months postoperatively. Bacterial cultures of the collected fluid were negative and histological examination confirmed the diagnosis of a cholesterol granuloma.  相似文献   
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63.
Extensive hydrolysis of whey protein isolate by Alcalase 2.4L produces a gel. The objectives of this study were to compare enzyme-induced gelation with the plastein reaction by determining the types of interactions involved in gelation. The average chain length of the peptides did not increase during hydrolysis and reached a plateau after 30 min to be approximately 4 residues, suggesting that the gel was formed by small molecular weight peptides held together by non-covalent interactions. The enzyme-induced gel network was stable over a wide range of pH and ionic strength and, therefore, showed some similarities with the plastein reaction. Disulfide bonds were not involved in the gel network. The gelation seems to be caused by physical aggregation, mainly via hydrophobic interactions with hydrogen bonding and electrostatic interactions playing a minor role.  相似文献   
64.
The objective of this study was to characterize the changes in peptide solubility resulting from changing some physicochemical conditions in a tryptic hydrolysate of beta-lactoglobulin (beta-LG). The turbidity (500 nm) of a 1% solution of tryptic peptides was measured at pH 3-10, at 5, 25, and 50 degrees C, in the presence of different salt concentrations (0, 0.5, and 1 M NaCl), in the presence of denaturing and reducing agents (6 M urea, 5% SDS, or 5% beta-mercaptoethanol), and under an electric field (isoelectric focusing). The results reveal an increase in turbidity of the peptide solution at pH 4, but a slight increase in turbidity was also observed at pH 8, which is attributable to peptides linked by disulfide bridges. The effect of temperature and ionic strength on the turbidity occurring at pH 4 indicates that mainly hydrophobic interactions are involved in the aggregation process. The material in the precipitate at pH 4 was identified as the peptides beta-LG 1-8, 15-20, and 41-60 and non-hydrolyzed alpha-lactalbumin. These results suggest that a limited number of peptides are involved in the aggregation process observed at pH 4, some of which having bioactive (beta-LG 15-20, ACE inhibitor, and opioid) or emulsifying properties (beta-LG 41-60). Aggregation of these peptides at acidic pH indicates that a simple acidification step could represent an easy process for isolating peptidic fractions enriched in bioactive or functional peptides.  相似文献   
65.
Isothermal titration calorimetry (ITC) was used to determine the binding constant, stoichiometry, enthalpy, and entropy of beta-lactoglobulin/low- and high-methoxyl pectin (beta-lg-LM- and HM-pectin) complexes at 22 degrees C and at pH 4. The binding isotherms revealed the formation of soluble intrapolymer complexes (C1) further followed by their aggregation in interpolymer complexes (C2). The interaction between beta-lg and LM- or HM-pectin in C1 and C2 occurred spontaneously with a Gibbs free energy around -10 kcal/mol. The C1 were enthalpically driven, whereas enthalpic and entropic factors were involved in the C2 formation. Because ITC did not allow the dissociation of different enthalpic contributions, the values measured as pectin and beta-lg interacted could partially be attributed to conformational changes. The C1 had a binding stoichiometry of 8.3 and 6.1 beta-lg molecules complexed per LM- or HM-pectin molecule, respectively. The C2 had about 16.5 and 15.1 beta-lg molecules complexed per LM- and HM-pectin, respectively.  相似文献   
66.
Ecophysiology of black walnut (Juglans nigra L.) along a vertical canopy gradient was studied in a mixed species plantation for the first (2007) and second (2008) growing seasons after thinning to understand response mechanisms to increased resource availability. Parameters were affected by the thinning treatment in 2008 only. Thinned trees showed increased light-saturated maximum photosynthesis (Amax) from 2007 to 2008 compared to non-thinned trees. This response was likely due to increased light levels near thinned trees (vs. changes in water or nutrient status), because thinning did not affect midday leaf water potential (Ψmd), average daily soil water content (SWC), or leaf nitrogen content per unit area (Na). Plantation thinning did not increase relative diameter growth during the experimental period. This may be due to low thinning intensity and mortality prior to thinning that reduced competition from first-tier neighbors. Certain leaf traits such as leaf mass per unit area (LMA) and Na increased from the bottom to the upper canopy position, but did not influence thinning responses. Distribution patterns of photosynthetic parameters through the vertical canopy gradient were less defined than leaf structural traits such as LMA and Na. Findings reflect black walnut's large variability in response to thinning.  相似文献   
67.
Naturally occurring cancer in companion animals parallels cancer in man more closely than does experimentally induced cancer in inbred laboratory animals. In dogs and cats, as in man, a role for immune responses is indicated in the development of tumors. A survey is presented based on the literature and our own studies concerning the immunological and immunotherapeutic aspects of canine and feline mammary neoplasia. In dogs bearing mammary neoplasms, circulating immune complexes appear to play a negative role in the generation of effective antitumor immune responses. The functional role of peripheral blood lymphocytes and tumor-infiltrating lymphocytes in dogs and cats with mammary tumors is not yet fully established. No tumor antigen responsible for humoral or cellular responses has yet been identified. Extracorporeal perfusion of serum of dogs with mammary tumors and subcutaneous administration of mitomycin- and neuraminidase-treated autologous tumor cells are associated with improved prognosis. The opposite was true for i.v. treatment with BCG or Corynebacterium parvum vaccine in our study, in contrast to a previous report. A number of other treatment modalities in cats and dogs with mammary carcinomas failed to induce tumor regression. Canine and feline mammary carcinomas are good candidates for modern immunotherapeutic approaches.  相似文献   
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69.
The role of ocular muscle proprioception in visual localization of targets   总被引:4,自引:0,他引:4  
The role of ocular muscle proprioception in the localization of visual targets has been investigated in normal humans by deviating one eye to create an experimental strabismus. The passively deviated eye was covered and the other eye viewed the target. With a hand-pointing task, targets were systematically mislocalized in the direction of the deviated nonviewing eye. A 4- to 6-degree error resulted when the nonviewing eye was offset 30 degrees from straight ahead. When the eye was deviated, the perceived "straight-ahead" was also displaced, by a similar amount, in the same direction. Since the efferent motor commands to the displaced and to the nondisplaced eyes are presumably identical by the law of equal innervation, the mislocalization of visual objects must be attributed to the change in proprioceptive information issued from the nonviewing, deviated eye. Thus proprioception contributes to the localization of objects in space.  相似文献   
70.
Mycobacterium species have long been recognised as a significant source of morbidity and mortality in finfish aquaculture, as well as in wild finfishes. Mycobacteria infecting fishes also include zoonotic pathogens that can cause protracted illness, especially in immunocompromised individuals. Several basic aspects of mycobacterial pathobiology in aquatic animals remain poorly understood, although a number of important recent developments have been made, especially with respect to identification of novel Mycobacterium spp. infecting fishes and a new group of mycobacteria closely related to the human pathogen Mycobacterium ulcerans. This review will encompass important aspects of mycobacterial disease in fishes, discuss recent research including studies of mycobacteriosis in striped bass (Morone saxatilis) of Chesapeake Bay, USA, and suggest directions for future work.  相似文献   
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