Distribution and management of cattle in relation to climatic zones within North America

The United States has a diversity of climates, as noted earlier. Although one can describe, as was done here, a grid of zones based on average temperature, rainfall, and terrain, the complexity of climates within these zones based on elevation, rainfall, and temperature requires much closer evaluation. The practicing veterinarian or animal husbandman must evaluate the specific climatic conditions prevailing on the farm or ranch in question and integrate the components of that climate into the management or health practices to be recommended. There is no substitute for careful observation.     

The effects of benzimidazole anthelmintics on P4501A in rat hepatocytes and HepG2 cells

Benzimidazole anthelmintics including albendazole, fenbendazole, and mebendazole are widely used in veterinary medicine. The effects of these benzimidazoles on cytochrome P4501A were investigated in primary cultures of rat hepatocytes and in the HepG2 cell line. After incubation of rat hepatocytes and HepG2 for 24-, 48-, and 72-h cells with drugs at various concentrations (0.1-50 microM), the enzyme activities associated with P4501A1/2 (7-ethoxyresorufin O-deethylation and 7-methoxyresorufin O-demethylation) were measured. The P4501A1/2 protein levels in both model systems were determined by Western blotting. Although all benzimidazoles provoked a significant increase of P4501A1/2 protein levels and P4501A activities, large differences in the induction response were found which was dependent on drug structure, concentration, and model system used. Based on the results, relationships between induction potency and structure of drug were demonstrated, as well as differences between the in vitro systems used. Therefore, pharmacological and toxicological consequences of cytochrome P4501A induction by benzimidazole drugs should be taken into account in veterinary therapy.     

Comparison of electrophoretograms of normal canine serum and plasma and of serum and plasma of hemolyzed specimens.

Comparison of the electrophoretograms of normal canine plasma and serum revealed a greater concentration of the beta3-fraction in plasma due to the presence of fibrinogen. When serum or plasma of hemolyzed canine blood was analyzed electrophoretically, there were slurring of the beta-globulin peaks due to the presence of free hemoglobin and increases in alpha2-globulins due to the formation of the haptoglobin-hemoglobin complex.     

Comparative anatomy of the meniscofemoral ligament in humans and some domestic mammals

The purpose of this study was to investigate the presence, position and relative sizes of the meniscofemoral ligaments (MFL) in three quadrupeds and humans and relate these to the caudal slope of the lateral tibial plateau. Canine, ovine and equine stifles and human knees were dissected to identify the presence of MFLs, their obliquity in relation to the caudal cruciate ligaments (CCL), the relative size and shape of the MFLs compared with the CCL, the points of femoral attachment of the MFLs and CCL, and the distance between the MFLs and CCL at their midpoints. The lateral tibial condyle was divided sagittally with a handsaw and the caudal slope was measured. An MFL was present in all quadrupeds. It was caudal to the CCL, being analogous to the human posterior MFL. There was no structure analogous to the human anterior MFL, a structure that has a different femoral attachment from the human posterior MFL and MFLs in other species examined. The meniscotibial attachments were of varying sizes. The size ratio between the MFL and CCL was greater in all three quadrupeds than it was in the human knee. The MFL lies more obliquely than the CCL in all species examined. The caudal tibial slope was steeper in the quadrupeds. In the stifle joints of quadrupeds, the MFL is a substantial structure and appears to be related to the caudal tibial slope. It is known to resist caudal translation of the tibia in conjunction with the lateral meniscus. This must be borne in mind when considering its function in the human knee.     

Synchronous climate changes in antarctica and the north atlantic

Central Greenland ice cores provide evidence of abrupt changes in climate over the past 100,000 years. Many of these changes have also been identified in sedimentary and geochemical signatures in deep-sea sediment cores from the North Atlantic, confirming the link between millennial-scale climate variability and ocean thermohaline circulation. It is shown here that two of the most prominent North Atlantic events-the rapid warming that marks the end of the last glacial period and the Bolling/Allerod-Younger Dryas oscillation-are also recorded in an ice core from Taylor Dome, in the western Ross Sea sector of Antarctica. This result contrasts with evidence from ice cores in other regions of Antarctica, which show an asynchronous response between the Northern and Southern Hemispheres.     

Gelation of Waxy Barley Starch Hydrolysates

Thealpha-amylolysis of gelatinized waxy barley starch and the gelation of the hydrolysates was studied. The progress of the hydrolysis was monitored with gel permeation and ion exchange chromatography. Initial attack occurred mainly between the clusters, without significant hydrolysis of the external chains. The stiffness of 20% gels prepared from the polymeric products decreased with increasing hydrolysis of the amylopectin. A linear relationship between the shear modulus and the original high-molecular weight amylopectin content was observed. Although the branched degradation products of amylopectin (average DP <6×10⁴) were not involved in network formation, they retained their ability to recrystallize as analysed by differential scanning colorimetry. For more extensively hydrolysed products (average DP <5000) no recrystallization or gel formation was observed under the conditions tested. Information on the gel structure was obtained with acid hydrolysis and ion exchange chromatography. The structure of the acid-resistant gel residues was complicated, showing a five-peak distribution when analysed with ion exchange chromatography. No differences between the original and hydrolysate gels was observed. The gel residues were resistant to isoamylase.     

Evaluation of cytokine production by equine alveolar macrophages exposed to lipopolysaccharide, Aspergillus fumigatus, and a suspension of hay dust

OBJECTIVE: To evaluate cytokine production by equine alveolar macrophages after exposure to lipopolysaccharide (LPS), Aspergillus fumigatus, and hay dust, and determine the effect of clenbuterol on the cytokine response. ANIMALS: 6 horses. PROCEDURE: Alveolar macrophages were exposed to PBS solution (negative control), LPS, hyphae and conidia of Aspergillus fumigatus (AF), or a suspension of hay dust (HDS) and incubated for 24 hours at 37 degrees C. Concentrations of tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta were measured in the supernatant. The procedure was repeated with cells that were concurrently incubated with 0.5 microM clenbuterol. RESULTS: Exposure to HDS and AF significantly increased production of TNF-alpha by equine alveolar macrophages. The increase in TNF-alpha produced in response to HDS and AF was 5 and 7 times as great, respectively, as the increase measured in response to LPS. The concentration of IL-1beta in the supernatant was significantly increased after exposure of cells to AF. Clenbuterol was effective at inhibiting TNF-alpha production by cells exposed to LPS, HDS, or AF. CONCLUSIONS AND CLINICAL RELEVANCE: Increased production of TNF-alpha and IL-1 indicated that the pro-inflammatory cytokines produced by alveolar macrophages in response to allergens may play a role in recurrent airway obstruction (RAO) in horses. Equine alveolar macrophages are not only a primary pulmonary defense mechanism but may also influence the pathogenesis of equine RAO. The beta2-adrenoceptor agonist clenbuterol, a drug that is commonly used for treatment of equine RAO, promotes immediate bronchodilation and may also contribute to downward modulation of the inflammatory response.