Technical note: recombinant LHRH fusion protein suppresses estrus in heifers

A recombinant luteinizing hormone-releasing hormone (LHRH) fusion protein was evaluated for its effectiveness in suppression of estrus in heifers. Eight heifers were randomly assigned to two equal treatment groups. Treatments consisted of recombinant ovalbumin-LHRH-7 or recombinant ovalbumin (control). This recombinant chimeric fusion protein consisted of ovalbumin with seven LHRH peptides (ovalbumin-LHRH-7). The plasmid for this protein was expressed in E. coli and was collected and purified as an insoluble protein. One milligram of the respective proteins was suspended in 2 mL of Z-Max adjuvant and administered by intramammary injection three times at 7-wk intervals. Luteinizing hormone-releasing hormone antibody binding was elevated in heifers treated with ovalbumin-LHRH-7 compared to ovalbumin-treated heifers (P < .05). Serum progesterone concentrations (< 1 ng/mL) indicate that the estrous cycle of the four heifers treated with ovalbumin-LHRH-7 was suppressed for a time period ranging from 60 to 238 d, which was different from control heifers (P < .01). Serum progesterone for the control heifers continued to exhibit cyclic profiles over the experimental period. This preliminary study in heifers demonstrated that a chimeric LHRH fusion protein induced elevated concentrations of circulating LHRH antibodies that suppressed estrus for an average of 122 +/- 41 d.     

Infection of a canine macrophage cell line with leishmania infantum: determination of nitric oxide production and anti-leishmanial activity

We have previously shown that resistance to Leishmania infantum in dogs is associated with a Th1 type of immune response. In this study, we use a canine macrophage cell line (030-D) that can readily be infected with this protozoan parasite. Our aim is to further characterize the effector mechanisms involved in killing of Leishmania parasite in dogs. We observed that activation of 030-D cells by incubation with a supernatant derived from a Leishmania-specific T cell line containing IFN-gamma, TNF-alpha and interleukin-2 (IL-2) resulted in enhanced nitric oxide (NO) production by these cells. In addition, we observed enhanced anti-leishmanial activity of infected 030-cells after activation. Both, NO production and anti-leishmanial activity were abrogated by addition of L-N(G)-nitroargininemethyl ester (L-NAME), an analogue of L-arginine. Thus, NO play an important role in the anti-leishmanial activity of these canine macrophages. We propose the infection of the 030-D cell line as a good in vitro model to further investigate parasite-host cell interactions in dogs, a natural host of Leishmania parasites.     

Hendra and Nipah virus infections.

The most important clinical and pathological manifestation of Hendra virus infection in horses and humans is that of severe interstitial pneumonia caused by viral infection of small blood vessels. The virus is also capable of causing nervous disease. Hendra virus is not contagious in horses and is spread by close contact with body fluids, such as froth from infected lungs. Diagnosis should be based on the laboratory examination of blood, lung, kidney, spleen, and, if nervous signs are present, also of the brain. Evidence of infection with the more recently identified and related Nipah virus was found in the brain of one horse in which there was inflammation of the meningeal blood vessels. Fruit bats, especially Pteropus s., have been incriminated as the natural and reservoir hosts of both Hendra and Nipah viruses.     

Experimental investigations into the effect of Escherichia coli and Clostridium perfringens on the steroid estrone

Together with the faecal and the urinary discharge of animals and humans natural and synthetic estrogenes are excreted into the environment. About their degradation in the environment only few facts are known. Their reduction is probably of microbial enzymatical nature. For looking into that question it was investigated by in-vitro-attempts whether Escherichia coli or Clostridium perfringens influence the estrone. Therefore estrone was incubated together with the microorganisms tested (experimental groups) and without those (control groups) in nutrient medium for these bacteria over 48 hours with 37 degrees C (aerobic) or 42 degrees C (anaerobic). For the executed procedure an enzyme immunoassay was used. It could be seen that E. coli does not show a provable effect on the estrone concentration under this conditions. Whereas C. perfringens might have a potency for the degradation of the hormone tested. The experiments shows that there exists obviously a difference between estrone and 4-pregnene-20 beta-o1-3-one in the same system of test.     

Cardiomyopathy in Dystrophin-Deficient Hypertrophic Feline Muscular Dystrophy

A colony of cats affected with hypertrophic feline muscular dystrophy was used to study the occurrence of cardiomyopathy associated with dystrophin deficiency. Affected male and female cats, obligate carrier females, and unaffected healthy littermates were followed from 12 weeks of age into adulthood. Thoracic radiography, 2-D echocardiography, and 2-D-derived M-mode echocardiography were performed at 3-month intervals until 12 months of age and regularly thereafter. From 9 months of age, all affected cats had larger hearts than normal and carrier animals. Left ventricular wall thickness in systole and in diastole and interventricular septal thickness in systole were greater in affected cats 12 months and older when compared with normal or heterozygous animals (P < .05). The myocardium of affected cats was diffusely hypoechoic and thickened. Multiple hyperechoic foci were in the myocardium and papillary musculature. Shortening fraction was normal in all cats. Changes seen in carrier females included enlargement and hyperechogenicity of the papillary musculature after the age of 2 years. Gross and light microscopic examination revealed left ventricular wall thickening with multiple foci of mineralization in 2 of 5 hearts from dystrophin-deficient cats. Although approximately 10% of the normal dystrophin amount was present in the skeletal muscle, dystrophin could not be detected in the myocardium. Early onset concentric myocardial hypertrophy was present in all adult cats. Lesions were mainly localized in the myocardium of the left ventricular free wall and interventricular septum, papillary musculature, and the endocardium. Clinical signs of heart failure developed only infrequently in cats with hypertrophic feline muscular dystrophy.     

Canine X-linked severe combined immunodeficiency.

Canine X-linked severe combined immunodeficiency (XSCID) is due to mutations in the common gamma (gamma c) subunit of the IL-2, IL-4, IL-7, IL-9 and IL-15 receptors. The most striking clinical feature is a failure to thrive or 'stunted' growth. Recurrent or chronic infections begin at the time of decline of maternal antibody, usually between six and eight weeks of age. Affected dogs rarely survive past three to four months of age. The major pathologic feature of canine XSCID is a small, dysplastic thymus. Grossly identifiable lymph nodes, tonsils, and Peyer's patches are absent in XSCID dogs. During the neonatal period, XSCID dogs have few, if any, peripheral T cells and increased number of peripheral B cells. Some XSCID dogs do develop phenotypically mature, nonfunctional T cells with age, however, the absolute number of peripheral T cells remain significantly decreased compared to age-matched normal dogs. An interesting finding is that as soon as T cells begin to appear in XSCID dogs they rapidly switch from a CD45RA+ (naive) phenotype to a CD45RA- (activated or memory phenotype). One of the characteristic findings in XSCID dogs is an absent or markedly depressed blastogenic response of T cells in response to stimulation through the T cell receptor and when the necessary second messengers for cellular proliferation are directly provided that by-pass signals delivered through ligand-receptor interaction. The proliferative defect is due to the inability of T cells to express a functional IL-2 receptor. Canine XSCID B cells do not proliferate following stimulation with T cell-dependent B cell mitogens, however, they proliferate normally in response to T cell-independent B cell mitogens. Canine XSCID B cells are capable of producing IgM but are incapable of class-switching to IgG antibody production following immunization with the T cell-dependent neoantigen, bacteriophage phiX174. The number of thymocytes in the XSCID thymus is approximately 0.3% of the thymocytes present in the thymus of age-matched normal dogs. The proportion of CD4-CD8- thymocytes in XSCID dogs is increased 3.5-fold and the CD4+CD8+ population is decreased 2.3-fold. These findings demonstrate that (1) a functional gamma c is required for normal B and T cell function, (2) early T cell development is highly dependent upon a functional gamma c, and (3) B cell development can occur through a gamma c-independent pathway.     

Nonsurgical periodontal therapy

The primary etiology of periodontal disease is bacterial infection. Bacteria exist as a biofilm (plaque) on the tooth and soft-tissue surfaces of the mouth. Biofilm is extremely resistant to antimicrobial activity. To effectively treat periodontal disease, the bacterial load must be reduced to allow healing of the inflamed tissues. Reduction of the bacterial load can be accomplished by surgical methods, nonsurgical methods, or a combination of the two. This article focuses on the nonsurgical treatment of periodontal disease. A thorough oral examination, which includes visual inspection and the use of a periodontal probe, is needed to determine the best therapy. Supragingival cleaning with power and hand scalers is the first step in the therapy process. The next step, subgingival scaling, is necessary to remove bacteria that are in direct contact with the periodontium. Effective subgingival plaque removal is time intensive and requires motivation, manual dexterity, and meticulous technique. Most veterinarians and veterinary technicians lack the training, instruments, and time to remove subgingival plaque effectively. To improve therapeutic results, adjunctive therapy in the form of oral systemic antibiotics or a locally applied doxycycline-containing polymer may be used. The success of periodontal therapy also is dependent on dental home care that takes place after professional treatment. The veterinarian and staff must be willing to educate and reinforce the dental home care efforts of the pet owner.     

Theileriosis in a Missouri beef herd caused by Theileria buffeli: case report, herd investigation, ultrastructure, phylogenetic analysis, and experimental transmission

A 6-year-old Simmental cow infected with Theileria buffeli had a clinical disease characterized by theilerial parasitemia, macrocytic normochromic anemia with acanthocytosis and spherocytosis, lymphoid hyperplasia (lymphocytosis, edematous lymphadenomegaly), dysproteinemia, evidence of liver disease, and a low serum antibody titer against T. buffeli. The cow was in a herd in which all cattle originated in Missouri; 22/75 (29%) of cattle had a theilerial parasitemia and 26/75 (35%) had titers to T. buffeli of > or =1:160. Classification of the Missouri bovine organism as T. buffeli was based on DNA sequencing and comparison to sequences for T. buffeli and Theileria sp. type A obtained from GenBank. Intraerythrocytic veils and piroplasms were seen during transmission electron microscopy. The organism was successfully transmitted to two splenectomized calves, which developed mild anemias while parasitemic. Blood from the second calf was used as the source of T. buffeli antigen for an indirect immunofluorescence antibody test. Theilerial isolates from a Missouri white-tailed deer were also sequenced and resembled Theileria sp. types F and G and were not consistent with the bovine organism.