储粮生态系统的跨学科和多学科研究——加拿大曼尼托巴大学在粮食储藏研究上的最新进展

加拿大曼尼托巴大学的跨学科储粮研究团队对储粮生态系统的各个方面进行了系统的研究。该团队的最新研究活动包括:储粮生态系统建模,粮堆热点的发生和安全储存条件,粮堆气流流动,害虫在粮堆中的迁移、分布与对其取样、诱捕的关系,以及计算机图像处理技术。这些研究增进了我们对储粮生态系统的认识与理解,为粮食储运的安全性及高效率技术创新奠定了基础。     

Evaluation of a combined transcutaneous carbon dioxide pressure and pulse oximetry sensor in adult sheep and dogs

OBJECTIVE: To evaluate a combined transcutaneous carbon dioxide pressure (tcPCO(2)) and pulse oximetry sensor in sheep and dogs. ANIMALS: 13 adult sheep and 11 adult dogs. PROCEDURES: During inhalation anesthesia, for the first 10 minutes following sensor placement, arterial blood gas was analyzed and tcPCO(2) was recorded every 2 minutes. Subsequently, the animals were hyper-, normo-, and hypoventilated. The simultaneously obtained tcPCO(2) and PaCO(2) values were analyzed by use of Bland-Altman statistical analysis. RESULTS: Mean +/- SD overall difference between tcPCO(2) and PaCO(2) 10 minutes after sensor application was 13.3 +/- 8.4 mm Hg in sheep and 8.9 +/- 12 mm Hg in dogs. During hyper-, normo-, and hypoventilation, mean difference (bias) and precision (limits of agreement [bias +/- 2 SD]) between tcPCO(2) and PaCO(2) values were 13.2 +/- 10.4 mm Hg (limits of agreement, -7.1 and 33.5 mm Hg) in sheep and 10.6 +/- 10.5 mm Hg (limits of agreement, -9.9 and 31.2 mm Hg) in dogs, respectively. Changes in PaCO(2) induced by different ventilation settings were detected by the tcPCO(2) sensor with a lag (response) time of 4.9 +/- 3.5 minutes for sheep and 6.2 +/- 3.6 minutes for dogs. CONCLUSIONS AND CLINICAL RELEVANCE: The tcPCO(2) sensor overestimated PaCO(2) in sheep and dogs and followed changes in PaCO(2) with a considerable lag time. The tcPCO(2) sensor might be useful for noninvasive monitoring of changes but cannot be used as a surrogate measure for PaCO(2).     

Influence of three anesthetic protocols on glomerular filtration rate in dogs

OBJECTIVE: To investigate renal function in clinically normal dogs when awake and during anesthesia with medetomidine; xylazine, ketamine, and halothane (XKH) combination; or propofol. ANIMALS: 10 adult female Beagles. PROCEDURES: At intervals of 15 days, dogs were administered medetomidine (0.05 mg/kg, IV); XKH combination (xylazine [1 mg/kg, IV], ketamine [5 mg/kg, IV], and halothane [1% end-tidal concentration]); or propofol (6 mg/kg, IV) to induce anesthesia or no treatment. Glomerular filtration rate was assessed on the basis of renal uptake (RU; determined via renal scintigraphy) and plasma clearance (CL) of technetium 99m-labeled diethylenetriamine pentaacetic acid ((99m)Tc-DTPA). RESULTS: In awake dogs, mean +/- SEM RU was 9.7 +/- 0.4% and CL was 3.86 +/- 0.23 mL/min/ kg. Renal uptake and CL of (99m)Tc-DTPA were not significantly modified by administration of XKH (RU, 11.4 +/- 0.9%; CL, 4.6 +/- 0.32 mL/min/kg) or propofol (RU, 9.7 +/- 0.3%; CL, 3.78 +/- 0.37 mL/min/kg). Half-life elimination time of plasma (99m)Tc-DTPA decreased significantly in XKH-anesthetized dogs, compared with the value in awake dogs (14.4 minutes and 28.9 minutes, respectively). However, glomerular filtration rate was significantly decreased by administration of medetomidine (RU, 3.9 +/- 0.1%), and the time to maximum kidney activity was significantly increased (867 +/- 56 seconds vs 181 +/- 11 seconds without anesthesia). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that anesthesia with propofol or an XKH combination did not alter renal function in healthy Beagles, but anesthesia with medetomidine decreased early RU of (99m)Tc-DTPA.     

Pulsed-field gel electrophoresis patterns and antimicrobial susceptibility phenotypes for coagulase-positive staphylococcal isolates from pustules and carriage sites in dogs with superficial bacterial folliculitis

OBJECTIVE: To determine whether coagulase-positive staphylococcal isolates that are genotypically the same strain obtained from pustules and carriage sites of individual dogs with superficial bacterial folliculitis have the same antimicrobial susceptibility phenotype. ANIMALS: 40 dogs with superficial bacterial folliculitis. PROCEDURES: Samples were obtained from 3 pustules and 3 carriage sites (ie, anus, nonlesional axillary skin, and nasal mucosa) for bacterial culture, morphologic identification, Gram staining, catalase and coagulase testing, antimicrobial susceptibility testing, speciation, and pulsed-field gel electrophoresis (PFGE). RESULTS: 223 isolates from pustules and carriage sites were included. Seventeen susceptibility phenotypes were found among isolates. One hundred twenty-eight (100%) isolates from pustules and 95 (100%) isolates from carriage sites were susceptible to cephalothin; 128 (100%) isolates from pustules and 94 (98.9%) isolates from carriage sites were susceptible to amoxicillin-clavulanic acid; 114 (89.1%) isolates from pustules and 82 (86.3%) isolates from carriage sites were susceptible to erythromycin and lincomycin hydrochloride; and 103 (80.5%) isolates from pustules and 70 (73.7%) isolates from carriage sites were susceptible to trimethoprim-sulfamethoxazole. In 37 of 39 (94.9%) dogs, isolates with the same PFGE pattern from multiple pustules had the same susceptibility phenotype. In 21 of 33 (63.6%) dogs, isolates from multiple carriage sites with the same PFGE pattern had the same susceptibility phenotype. CONCLUSIONS AND CLINICAL RELEVANCE: In dogs with superficial bacterial folliculitis, most coagulase-positive staphylococcal isolates from pustules that are genotypically the same strain will have the same susceptibility phenotype and treatment may be based on empiric antimicrobial selection or susceptibility testing of 1 lesional isolate.     

Changes in the myocardial performance index during dobutamine administration in anesthetized cats

OBJECTIVE: To investigate the relationship between myocardial performance index (MPI; also known as the Tei index) and cardiac function in anesthetized cats administered dobutamine. ANIMALS: 6 adult cats. PROCEDURES: Cats were anesthetized by administration of propofol (6 mg/kg, IV), and anesthesia was maintained by administration of isoflurane. Heart rate and systolic arterial pressure (SAP) were monitored. Stroke volume, cardiac output, and aortic blood flow (ABF) were measured by use of transesophageal ultrasonography. Left ventricular fractional shortening (LVFS), mitral E-wave velocity-to-A-wave velocity (E:A) ratio, and ejection time were measured by use of transthoracic echocardiography. Dobutamine was administrated via a cephalic vein at rates of 2.5, 5.0, and 10 microg/kg/min. RESULTS: Heart rate, SAP, cardiac output, and ABF increased with dobutamine administration, whereas stroke volume significantly decreased. The LVFS significantly increased, and the E:A ratio significantly decreased. Total isovolumic time and the MPI significantly decreased. The MPI was negatively correlated (r=-0.63) with LVFS. Conversely, the MPI was positively correlated with the E:A ratio (r=0.47), stroke volume (r=0.66), and total isovolumic time (r=0.95). However, the MPI was not significantly correlated with heart rate, SAP, cardiac output, or ABF. CONCLUSION AND CLINICAL RELEVANCE: Analysis suggested that the MPI provides a sensitive clinical assessment of cardiac response to medication in cats, which may be similar to the usefulness of the MPI reported in humans.     

Cerebral Blastomyces dermatitidis infection in a cat

CASE DESCRIPTION: An 8-year-old domestic shorthair cat was evaluated because of signs of depression, circling, and visual deficits. CLINICAL FINDINGS: The cat had no cutaneous lesions, and results of an ophthalmologic examination and thoracic radiography were within reference limits. Computed tomography of the brain revealed a mass lesion involving the right parietal, temporal, and occipital lobes; the mass was in broad-based contact with the skull and smoothly marginated and had strong homogenous enhancement after contrast agent administration. During craniectomy, samples of the mass were collected for cytologic and histopathologic evaluations and microbial culture. A diagnosis of Blastomyces dermatitidis-associated meningoencephalitis with secondary pyogranulomatous inflammation was made. TREATMENT AND OUTCOME: Amphotericin B (0.25 mg/kg [0.11 mg/lb], IV) was administered on alternate days (cumulative dose, 1.75 mg/kg [0.8 mg/lb]). To minimize the risk of nephrotoxicosis, assessments of serum biochemical variables (urea nitrogen and creatinine concentrations) and urinalyses were performed at intervals. The third dose of amphotericin B was postponed 48 hours because the cat became azotemic. The cat subsequently received fluconazole (10 mg/kg [4.5 mg/lb], PO, q 12 h) for 5.5 months. Six months after discontinuation of that treatment, the cat appeared healthy and had no signs of relapse. CLINICAL RELEVANCE: Brain infection with B dermatitidis is typically associated with widespread disseminated disease. The cat of this report had no evidence of systemic disease. Blastomycosis of the CNS should be considered as a differential diagnosis for brain lesions in cats from areas in which B dermatitidis is endemic.     

Clinical characteristics and mode of inheritance of familial focal seizures in Standard Poodles

OBJECTIVE: To determine clinical characteristics and mode of inheritance of seizures in a family of Standard Poodles. DESIGN: Case series. ANIMALS: 90 Standard Poodles descended from the same maternal bloodline (30 with probable idiopathic epilepsy [PIE] and 60 without any history of seizures). PROCEDURES: Researchers contacted owners to determine whether dogs had ever had any seizures and, if so, the nature of any such seizures and any potential underlying causes. Dogs were considered to have PIE if they were between 6 months and 7.5 years old at the time of seizure onset and had no evidence of any underlying cause. To determine the mode of inheritance, segregation analyses were designed to allow the family to be analyzed as a whole, as opposed to as nuclear families. Competing models of inheritance were compared statistically for their ability to explain the data. RESULTS: Of the dogs with PIE, 28 (93%) had focal onset seizures with or without secondary generalization. Median age of onset was 3.7 years; 6 dogs were > 5 years old at the onset of seizures. Segregation analyses strongly suggested that PIE was inherited as a simple recessive autosomal trait with complete or almost complete penetrance. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that in this family of Standard Poodles, PIE was inherited as a simple recessive autosomal trait with complete or almost complete penetrance. Seizures often had focal, as opposed to generalized, onsets, and it was not uncommon for seizures to begin after 5 years of age.