Pasteurella haemolytica A1 and Bovine Respiratory Disease: Pathogenesis     

Laurence O. Whiteley DVM  PhD    Samuel K. Maheswaran BVSc  PhD    Douglas J. Weiss DVM  PhD    Trevor R. Ames DVM  MS  Mathur S. Kannan BVSc  PhD 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1992,6(1):11-22

The severe fibrinonecrotic pneumonia associated with pneumonic pasteurellosis usually results from colonization of the lower respiratory tract by Pasteurella haemolytica biotype A, serotype 1(A1). Despite recent research efforts, the authors lack a detailed understanding of the interactions and host response to P. haemolytica in the respiratory tract. The authors hypothesize that management and environmental stress factors or viral infection alters the upper respiratory tract (URT) epithelium allowing P. haemolytica to colonize the epithelium. Once the URT is colonized, large numbers of organisms enter the lung where they interact with alveolar macrophages. Endotoxin, released from the bacteria, crosses the alveolar wall where it activates pulmonary intravascular macrophages, endothelium, neutrophils, lymphocytes, platelets, complement, and Hageman factor leading to complex interactions of cells and mediators. It is the progression of this inflammatory response with neutrophil influx that is ultimately responsible for the pulmonary injury. Leukotoxin is a major virulence factor of P. haemolytica that allows it to survive by destroying phagocytic cells. At subcytolytic concentrations it may also enhance the inflammatory response by activating cells to produce mediators and release reactive oxygen metabolites and proteases.  相似文献   

Methods for evaluating genotype-environment interactions illustrated by laying hens     

Mathur PK  Horst P 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》1994,111(1-6):265-288

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Rust of Queensland arrowroot (Canna edulis) caused by Puccinia thaliae: a new record for India     

M. L. Jeeva  V. Hegde  T. Makeshkumar  S. Sriram  R. R. Nair  S. Edison  N. Mathur 《Plant pathology》2004,53(2):261-261

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Efficacy of a mephentermine‐based product as a vasopressor and a cardiac performance enhancer when given intramuscularly to cattle          下载免费PDF全文

D. N. Q. Cunha  C. L. del Rio  B. L. Youngblood  E. L. Ferris  G. E. Geist  Y. Ueyama  L. C. Franz  S. Mathur  R. L. Hamlin 《Journal of veterinary pharmacology and therapeutics》2018,41(2):274-280

The goal of this study was to confirm the vasopressor and cardiac effects of POTENAY^® INJETÁVEL (POT), a mephentermine‐based product, given to cattle with induced vascular/cardiac depression. Ten healthy Holstein cattle (206 ± 13 kg) followed a randomized‐complete‐block design (RCBD) utilizing crossover study design. Each animal randomly received (1 ml/25 kg, IM) of either POT (n = 10) or volume‐matched placebo control (0.9%NaCl, CP, n = 10). A subset of animals (n = 5) received POT first (day 0) while the remaining (n = 5) received CP; after a six‐day washout period, cattle received the opposite compound. Animals were anesthetized and catheterized for systemic/left ventricular hemodynamic monitoring. Myocardial dysfunction/hypotension was induced by increasing the end‐tidal isoflurane concentration until arterial blood pressure was 20% lower than at baseline and remained stable. Once the animal was determined to be hypotensive and hemodynamically stable, steady‐state hypotensive baseline data (BL2) were acquired, and treatment with either POT or CP was given. Data were acquired post‐treatment at every 15 min for 90 min. POT improved cardiac output (+68 L/min, ±14%, p < 0.05), MAP (+14 mmHg, ±4%, p < 0.05), HR (+22 bpm, ±8%, p < 0.05), and peak rates of ventricular pressure change during both systole (dP/dt_max: +37 mmHg/s ±13%, p < 0.05) and diastole (dP/dt_min: +31 mmHg/s, ±7%, p < 0.05). No improvements were noted following placebo‐control administration. Results indicate that POT improves cardiac performance and systemic hemodynamics in cattle with induced cardiovascular depression when given as single intramuscular injection.  相似文献   

Rates of passage of some arid zone roughages through the digestive tract of sheep     

G R Purohit  C S Mathur 《The Indian veterinary journal》1971,48(4):361-365

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Effects of the calcium channel antagonist amlodipine in cats with surgically induced hypertensive renal insufficiency   总被引：4，自引：0，他引：4  

Mathur S  Syme H  Brown CA  Elliot J  Moore PA  Newell MA  Munday JS  Cartier LM  Sheldon SE  Brown SA 《American journal of veterinary research》2002,63(6):833-839

OBJECTIVE: To determine whether amlodipine besylate decreases systemic arterial blood pressure (BP) and reduces the prevalence of complications in cats with induced hypertensive renal insufficiency. ANIMALS: 20 cats with partial nephrectomy. PROCEDURE: Following reduction in renal mass, 10 cats were administered 0.25 mg of amlodipine/kg, PO, q 24 h (group A). Ten cats served as a control group (group C). Systolic BP (SBP), diastolic BP (DBP), and mean BP (MBP), physical activity, and pulse rate were measured continuously for 36 days by use of radiotelemetric devices. RESULTS: Compared with values for clinically normal cats, SBP, DBP, and MBP were significantly increased in cats of group C. Cats in group A had significant reductions in SBP, DBP, and MBP, compared with values for cats in group C. Albuminuria but not urine protein-to-creatinine ratio was significantly correlated (R2 = 0.317) with SBP in hypertensive cats. Prevalence of ocular lesions attributable to systemic hypertension in group C (7 cats) was greater than that observed in group A (2). Two cats in group C were euthanatized on day 16 because of nuerologic complications attributed to systemic hypertension. One normotensive cat in group A was euthanatized because of purulent enteritis of unknown cause on day 27. CONCLUSIONS AND CLINICAL RELEVANCE: Amlodipine had an antihypertensive effect in cats with coexistent systemic hypertension and renal insufficiency. Its use may improve the prognosis for cats with systemic hypertension by decreasing the risk of ocular injury or neurologic complications induced by high BP.  相似文献   

Suppression of Rice Blast by Preinoculation with Avirulent Pyricularia oryzae and the Nonrice Pathogen Bipolaris sorokiniana     

Manandhar HK  Lyngs Jørgensen HJ  Mathur SB  Smedegaard-Petersen V 《Phytopathology》1998,88(7):735-739

ABSTRACT Avirulent isolates of Pyricularia oryzae and isolates of Bipolaris sorokiniana, a nonrice pathogen, were used to suppress rice blast caused by P. oryzae. In greenhouse experiments, both fungi substantially reduced leaf blast when applied 24 h or more before the pathogen. B. sorokiniana, but not avirulent isolates of P. oryzae, systemically reduced disease in leaf 5 when applied to whole plants at the four-leaf stage. In field experiments, both fungi were able to reduce neck blast significantly. No increase in grain yield was obtained by using avirulent isolates of P. oryzae, whereas five sprays with B. sorokiniana from seedling to heading stages increased the grain yield in two of three experiments conducted at two locations in Nepal. The significant increase in yield was observed under high inoculum pressure of P. oryzae. Induced resistance is suggested to be involved in the suppression of disease.  相似文献   

Structural and Functional Changes in Porcine Cumulus-Oocyte-Complexes During Preovulatory Maturation     

H Torner  KP Brtissow  W Tomek  H Aim  J Rátky 《Reproduction in domestic animals》1998,33(3-4):249-253

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The relative immobility of fertilizer and native copper in an organic soil under field conditions     

S. P. Mathur  M. P. Lévesque  J. G. Desjardins 《Water, air, and soil pollution》1979,11(2):207-215

Twelve profiles were obtained from a 2 ha field, 6 from where Cu had been applied for 15 yr and 6 from areas not fertilized with Cu. The 30 to 50 cm layers in the profiles in both areas contained similar amounts of Cu indicating a lack of vertical migration of the fertilizer metal under field conditions. A buried layer of humified material was found mostly between 50 and 60 cm depth. Of the mineral elements which enriched this layer during degradation and humification, perhaps a few thousand years ago, Cu, Pb and Mn were apparently retained more than Ca, Fe, Ni, Al, Mg, Zn and K.  相似文献   

Bioconcentration of HCH isomers by the ciliate protozoan,Tetrahymena pyriformis under laboratory conditions     

Ranjana Mathur  D. M. Saxena 《Water, air, and soil pollution》1987,32(3-4):323-327

Tetrahymena pyriformis, a common freshwater ciliate concentrated the four common HCH (Hexachlorocyclohexane) isomers viz., α, β, δ, and γ to varied extent. Bioconcentration factor [as expressed by the ratio of cellular insecticide in ng mg^?1 (dry weight) to supernatant in ng μL^?1 ranged from 342 to 2260 for α-HCH, 37 to 831 for β-HCH, 326 to 2806 for δ-HCH and from 106 to 1214 ppm for γ-HCH.  相似文献