Dermal mast cell counts in F2 Holstein x Gir crossbred cattle artificially infested with the tick Boophilus microplus (Acari : Ixodidae)

The role of dermal mast cells (DMC) in the host resistance to ticks has been studied but it is not totally explained yet. Studies have proposed that zebuine cattle breeds, known as highly resistant to ticks, have more DMC than taurine breeds. In the present study, we compared the number of adult female ticks Boophilus microplus and the mast cells' countings in the skin of F-2 crossbred Gir x Holstein cattle, before and after tick infestation. F-2 crossbred cattle (n = 148) were divided into seven groups and artificially infested with 1.0 x 10(4) B. nticroplus larvae and, 21 days afterwards, adult female-fed ticks attached to the skin were counted. Skin biopsies were taken and examined under light microscopy with a square-lined ocular reticulum in a total area of 0.0625 mm(2) in both the superficial and deep dermis. Results demonstrated that infested F-2 crossbred cattle acquired resistance against the cattle-tick B. microplus probably associated to an increase in the dermal mast cell number. It is concluded that the tick infestation may lead to an environmental modification in the dermis of parasitized hosts due to the massive migration of mast cells or their local proliferation.

Lidocaine effects on corneal endothelial cell ultrastructure

The purpose of this study was to determine whether intracameral commercial lidocaine 2% induces alterations on the rabbit corneal endothelium. Forty white rabbits received different substances inside the anterior chamber: group (G)1, no substance; G2 and G3 received lidocaine 2% with preservative in aqueous solution; G4 and G5, lidocaine 2% with preservative in gel solution; G6 and G7, the anesthetic preservative (metilparahydroxybenzoate 0.1%); and G8 and G9, lidocaine 2% without preservative in aqueous solution. The animals from G2, 4, 6 and 8 were sacrificed after 1 h, and from G3, 5, 7 and 9 after 24 h after injection of the substance inside the anterior chamber. The corneas were clinically evaluated and assessed by transmission and scanning electron microscopy. G1, 2, 6, 7, 8 and 9 animals had very similar characteristics in clinical, ultrastructural and morphometric evaluations; the G3 and G4 animals showed discrete edema and one animal in G5 had intense corneal edema. We conclude that lidocaine 2% with preservative induces few ultrastructural alterations in the corneal endothelial cells.

Corneal endothelial cell morphology of normal dogs in different ages

Endothelial cell function is essential to maintain corneal transparency, but unfortunately the regenerative capacity of the endothelium is limited. There are only a few reports describing the effect of age on morphologic appearance of corneal endothelial cells of dogs. Studies of normal corneal endothelial cells in humans and dogs have shown a decrease in endothelial cell density (ECD) and an increase in pleomorphism and polymegethism with advancing age. The purpose of this study was to investigate the effect of age on ECD and endothelial cell morphology in dogs. A total of 30 dogs were divided into three groups (10 dogs/group) based on age: group 1 (2-12 months old), group 2 (24-72 months old), and group 3 (84 months or older). Corneas were processed for light and scanning electron microscopy. Results showed only difference in cell density between group 1 and groups 2 and 3, showing an initial decrease in cell density as the animal matured. Whereas there was significantly greater variation in cell size within the dogs in group 3 than there was within the other two groups, suggesting that there was increased polymegethism and pleomorphism with advancing age.

Using Mastitis Records and Somatic Cell Count Data

On-farm records are essential for managing mastitis in dairy herds. Mastitis records are a useful tool for caring for an individual cow, to monitor compliance of farm personnel working with groups of animals, to understand the epidemiology of mastitis in the herd, to ensure responsible drug utilization, and to document accountability in care of the cow. Herds have become larger and more people are involved with individual animal care. This article describes a records plan that can be used to monitor mastitis at the herd level, aid in decision-making processes for individual cows, and improve drug use on dairy herds.

Experimental Basis and New Insights for Cell Therapy in Chronic Obstructive Pulmonary Disease

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The relationship between dairy cow hygiene and somatic cell count in milk

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Association between polyclonal B cell activation and the presence of autoantibodies in mice infected with Yersinia enterocolitica O:3

Eight-week old conventional female Swiss mice were inoculated intravenously with Yersinia enterocolitica O:3. A second group of normal mice was used as control. Five mice from each group were bled by heart puncture and their spleens were removed for spleen cell collection on the 3rd, 5th, 7th, 10th, 14th and 21st day after infection. Immunoglobulin-secreting spleen cells were detected by the isotype-specific protein A plaque assay. Total immunoglobulin levels were determined in mouse serum by single radial immunodiffusion and the presence of autoantibodies was determined by ELISA. We observed a marked increase in the total number of cells secreting immunoglobulins of all isotypes as early as on the 3rd day post-infection and the peak of secretion occurred on the 7th day. At the peak of the immunoglobulin response, the total number of secreting cells was 19 times higher than that of control mice and most immunoglobulin-secreting cells were of the IgG2a isotype. On the 10th day post-infection, total serum immunoglobul in values were 2 times higher in infected animals when compared to the control group, and continued at this level up to the 21st day post-infection. Serum absorption with viable Y. enterocolitica cells had little effect on antibody levels detected by single radial immunodiffusion. Analysis of serum autoantibody levels revealed that Y. enterocolitica infection induced an increase of anti-myosin and anti-myelin immunoglobulins. The sera did not react with collagen. The present study demonstrates that Y. enterocolitica O:3 infection induces polyclonal activation of murine B cells which is correlated with the activation of some autoreactive lymphocyte clones.

Cell death in ovarioles causes permanent sterility in Frieseomelitta varia worker bees

Frieseomelitta varia worker bees do not lay eggs even when living in queenless colonies, a condition that favors ovary development and oviposition in the majority of highly social bees. The permanent sterility of these worker bees was initially attributed to a failure in ovary morphogenesis and differentiation. Using transmission electron microscopy we found that at the beginning of the pupal phase the ovaries of F. varia workers are formed by four ovarioles, each of them composed of 1) a terminal filament at the apex of the ovarioles, containing juxtaposed and irregularly shaped cells, 2) a germarium with clusters of cystocytes and prefollicular cells showing long cytoplasmic projections that envelop the cystocyte clusters, 3) fusiform interfollicular and basal stalk precursor cells, and 4) globular, irregularly contoured basal cells with large nuclei. However, during the pupal phase an accentuated and progressive process of cell death takes place in the ovarioles. The dying cells are characterized by large membrane bodies, electron-dense apoptotic bodies, vacuoles, vesiculation, secondary lysosomes, enlarged rough endoplasmic reticulum cisternae, swollen mitochondria, pycnotic nuclei, masses of chromatin adjacent to the convoluted nuclear envelope, and nucleoli showing signs of fragmentation. Cell death continues in ovarioles even after the emergence of the workers. Once they become nurse bees, the ovaries have become transformed into a cell mass in which structurally organized ovarioles can no longer be identified. In F. varia workers, ovariole cell death most certainly is part of the program of caste differentiation.

Peritoneal effusion in a dog secondary to visceral mast cell tumor: A case report

BACKGROUND: Mast cell tumor, one of the most common skin tumors in dogs, may also be found in visceral sites (mainly spleen and liver). When a visceral mast cell tumor is present, neoplastic mast cells may be found in any effusion secondary to the tumor. Therefore, the diagnosis may be made by cytologic analysis of the effusion. CASE: An 8-year-old, spayed, female Siberian husky presented with a peritoneal effusion secondary to a visceral mast cell tumor. Seven months earlier, the dog had presented with a cutaneous nodule diagnosed as a well-differentiated mast cell tumor. The peritoneal fluid was classified as a transudate. Numerous neoplastic mast cells were found in the effusion. Although the mast cell tumor presented with characteristics of the well-differentiated tumor, its biologic behavior was that of a malignant tumor. CONCLUSION: Care should be taken to evaluate the prognosis of mast cell tumors in dogs since their biologic behavior is extremely variable.

Factors affecting somatic cell counts and their relations with milk and milk constituent yield in buffaloes

Data concerning daily milk yield (MY), percentage of milk fat (%F), protein (%P), lactose (%LT), and total solids (%TS), and somatic cell counts (SCC) for a herd of 222 Murrah buffalo reared in the state of São Paulo, Brazil, were collected monthly from 1997 to 2000 in order to study the factors affecting SCC and their relation to milk production and constituents during lactation. SCC decreased in the second month of lactation and increased thereafter, up to the ninth month of lactation. The interaction of month of lactation x order of calving was significant. Mean MY observed during the first month of lactation was 6.87 kg, which increased to 7.65 kg during the second month, and then decreased until the ninth month of lactation (3.83 kg). During the different months of lactation, %F, %P, %LT, and %TS ranged from 6.28 to 8.38%, 4.05 to 4.59%, 4.96 to 5.34%, and 16.94 to 18.55%, respectively. Calving year, calving order, and order of month of lactation significantly affected MY, %F, %P, %LT, and %TS. The regression coefficients of transformed SCC on MY and %LT were negative and significant during all months of lactation, showing that milk and lactose yield decreased with increased transformed SCC, causing losses to buffalo milk producers.

Visceral mast cell tumor in a captive black jaguar (Panthera onca)

Little is known about neoplasia in the jaguar (Panthera onca), the largest American feline. A captive black jaguar was diagnosed at necropsy with a mastocytic form of visceral mast cell tumor similar to that which occurs in domestic cats. This animal had no previous clinical disease and died during anesthesia for a routine dental treatment.

Antigens from Rhipicephalus sanguineus ticks elicit potent cell-mediated immune responses in resistant but not in susceptible animals

In the present study we compared the immunological reactions between Rhipicephalus sanguineus tick-infested susceptible (dogs and mice) and tick-resistant hosts (guinea pigs), elucidating some of the components of efficient protective responses against ticks. We found that T-cells from guinea pigs infested with adult ticks proliferate vigorously in the presence of concanavalin A (ConA), whereas ConA-induced cell proliferation of tick-infested mice and dogs was significantly decreased at 43.1 and 94.0%, respectively, compared to non-infested controls. Moreover, cells from mice and dogs submitted to one or three successive infestations did not exhibit a T-cell proliferative response to tick antigens, whilst cells from thrice tick-infested guinea pigs, when cultured with either a tick extract or tick saliva, displayed a significant increase in cell proliferation. Also, we evaluated the response of tick-infested mice to a cutaneous hypersensitivity test induced by a tick extract. Tick-infested mice developed a significant immediate reaction, whereby a 29.9% increase in the footpad thickness was observed. No delayed-type hypersensitivity (DTH) reaction was detected. Finally, the differential cell count at the tick attachment site in repeatedly infested mice exhibited a 6.6- and 4.1-fold increase in the percentage of eosinophils and neutrophils, respectively, compared to non-infested animals, while a decrease of 77.0-40.9 in the percentage of mononuclear cells was observed. The results of the cutaneous hypersensitivity test and the cellular counts at the tick feeding site for mice support the view that tick-infested mice develop an immune response to R. sanguineus ticks very similar to dogs, the natural host of this species of tick, but very different from guinea pigs (resistant host), which develop a DTH reaction in addition to a basophil and mononuclear cell infiltration at the tick-attachment site. In conclusion, saliva introduced during tick infestations reduces the ability of a susceptible animal host to respond to tick antigens that could stimulate a protective immune response. As a consequence, the animals present a lack of DTH response and disturbed cellular migration to tick feeding site, which can represent a deficient response against ticks. © 2003 Elsevier B.V. All rights reserved.