Immunocytochemical study of tissues from clinically normal dogs and of neoplasms, using keratin monoclonal antibodies.

Three commonly used keratin monoclonal antibodies (MAB)--AE1:AE3, CAM 5.2, and MAK-6--were compared with routinely used cytokeratin antibody. The expression of these antibodies was analyzed in several tissues obtained from clinically normal dogs and in a variety of neoplasms from dogs. Using appropriate enzymatic digestion, paraffin-embedded tissues processed in routine manner retained their typical keratin expression. Differentiated and poorly differentiated epithelial neoplasms, lymphomas, and melanomas were studied by use of the avidin-biotin-peroxidase technique. All 4 of the aforementioned antibodies had similar staining profiles. Of 3 anaplastic carcinomas, 2 had positive reaction to all 4 antibodies. All lymphomas, plasma cell tumors, and amelanotic melanomas had negative reaction to MAK-6, CAM 5.2, AE1:AE3, and cytokeratin MAB. Three basal cell epitheliomas had positive reaction to all 4 antibodies, whereas 1 basal cell tumor with a solid pattern had negative staining reaction. Two carcinoids had negative reaction to all markers and 1 of 2 malignant chemodectomas and 1 transitional cell carcinoma had staining reaction to only AE1:AE3 MAB. Comparing the 4 antibodies, use of AE1:AE3 MAB produced the strongest staining intensity followed by cytokeratin, MAK-6, and CAM 5.2 MAB. All 4 antibodies had low background staining. In conclusion, AE1:AE3 and MAK-6 MAB are as useful as cytokeratin MAB for identification of poorly differentiated epithelial neoplasms in dogs and cats.     

Molecular epidemiology of Pasteurella multocida in turkeys.

Pasteurella multocida isolated from turkeys during an outbreak of fowl cholera was characterized by serotype and heterogeneity of genes encoding rRNA (ribotype) to investigate the epidemiology of the organism. Isolates were collected between October 1985 and July 1986. The M9 or Clemson University fowl cholera vaccine-like strain was detected in 17% of the flocks with fowl cholera. One particular strain, isolated only from breeder flocks, was recovered from 7 of the 10 breeder flocks examined in this study. Intracompany transmission appeared to be common, implying a failure in biosecurity. Circumstantial evidence indicated that in the field; the incubation period of P multocida in a turkey flock may be between 2 to 7 weeks. Wildlife did not appear to be an important reservoir of P multocida for turkeys during this study period. Ribotyping results tended to discount several of the possible interflock transmissions, as suggested by examination of serotyping results alone; however, serotyping in combination with ribotyping proved helpful in understanding the epidemiology of P multocida in turkeys.     

Effects of treatment with ticlopidine in heartworm-negative, heartworm-infected, and embolized heartworm-infected dogs.

Ticlopidine hydrochloride was evaluated for its effectiveness in inhibiting platelet aggregation and serotonin release in 5 laboratory Beagles before and after heartworm implantation with 7 adult Dirofilaria immitis, and after embolization with 7 dead heartworms to mimic what happens after heartworm adulticide treatment. Five other laboratory Beagles, similarly implanted and embolized with heartworms, were used as nonmedicated controls. During the heartworm-negative stage, the dosage of ticlopidine that inhibited adenosine diphosphate (ADP)-induced platelet aggregation in 5 dogs by at least 50% after 5 days of treatment was 62 mg/kg of body weight once a day. In the same dogs implanted with 7 adult heartworms 21 days previously, mean (+/- SD) ticlopidine dosage required to obtain similar results was 71 (+/- 13) mg/kg given once daily. During the 21 days after dead heartworms were implanted in heartworm-infected dogs, mean ticlopidine dosage was 108 (+/- 35) mg/kg (range, 62 to 150 mg/kg). Ticlopidine treatment was associated with increased platelet numbers in all 5 dogs during the heartworm-negative stage and in 4 of 5 dogs during the heartworm implantation and heartworm embolization stages. Mean platelet volume tended to decrease as platelet numbers increased. At necropsy, gross and histologic pulmonary lesions were less severe in ticlopidine-treated dogs than in nonmedicated control dogs.     

Sedative and cardiovascular effects of romifidine, alone and in combination with butorphanol, in the horse

The behavioural and sedative effects of intravenous (iv) romifidine (40 and 80 μg/kg bodyweight [bwt]) alone or in combination with iv butorphanol (50 μg/kg bwt) were investigated in four ponies and one Thoroughbred horse. Apparent sedation, as judged by the lowering of the head, and by the response to imposed touch, visual and sound stimuli was assessed. The combination with butorphanol reduced the animals' response to imposed stimuli when compared with the effect of the same dose of romifidine alone. Following the administration of romifidine/butorphanol combinations muzzle tremor was noted and some animals attempted to walk forward. In a separate series, the cardiopulmonary effects of iv romifidine (80 μg/kg bwt) alone, or in combination with butorphanol (50 μg/kg bwt) were investigated. Romifidine and the romifidine/butorphanol combination caused similar cardiovascular changes, these being bradycardia with heart block, and hypertension followed by hypotension. Romifidine caused a transient decrease in arterial oxygen tensions and arterial carbon dioxide tensions had increased significantly by the end of the 90 min recording period. Romifidine/butorphanol combinations produced significantly higher arterial carbon dioxide tensions during the first 15 mins after drug administration than did romifidine alone. Butorphanol at 50 μg/kg bwt iv reduced the response to imposed stimuli in horses sedated with romifidine. The combination produced no cardiovascular changes beyond those induced by romifidine alone, but did increase the degree of respiratory depression.     

Changes in the MHC Class II+ Dendritic Cell Population of Ovine Skin In Response to Orf Virus Infection

Abstract— Class II+ dendritic cells were widely distributed throughout normal ovine skin in two main locations: a) in or immediately adjacent to the epidermis and epidermal appendages and b) in the vicinity of the blood vessels. They are unlikely to represent a homogeneous population particularly since Langerhans cells, which previously have been found throughout the epidermal appendages, were located only in the epidermis using acetylcholinesterase staining. Following infection with orf virus, a dense mass of closely associated class II+ dendritic cells develops in the exposed necrotising dermis, adjacent to infected hair follicles and under infected degenerating epidermis. These cells interact and appear to form a barrier to invasion, a framework for immune defence and a template for subsequent epidermal repair; they seem to provide the basis of a highly integrated local dermal defence system. Résumé— Des cellules dendritiques de classe II+étaient largement réparties dans la peau ovine normale dans deux principales zones a) dans l'épiderme et les annexes épidermiques ou dans leur voisnage immédiat b) au voisinage des vaisseaux sanguins. Il est peu probable qu'elles représentant une population homogène particulièrement parce que les cellules de Langerhaps, qui ont été découvertes précédemment dans l'ensemble des annexes épidermiques, furent localisées seulement dans l'épiderme en utilisant une coloration à l'acétylcholinesterase. Après une infection par le virus de l'ecthyma, il se forme une masse dense de cellules dendritiques de classe II+étroitement associées, dans le derme nécrotique atteint, adjacente aux follicules pileux infectés et sous l'épiderme dégénératif infecté. Ces cellules interagissent et apparaissent former une barrière à l'invasion, un cadre pour les défenses immunitaires et un patron pour la réparation épidermique ultérieure; elles semblent fournir les bases d'un système de défense dermique local hautement intégré. Zusammenfassung— Klasse II+-Dendritenzellen waren in der gesamten Haut von normalen Schafen in vorwiegend zwei Bereichen verbreitet: a) in oder unmittelbar neben der Epidermis und der epidermalen Anhangsgebiete und b) in dor Nähe dar Blutgefäße. Sie stellen wahrscheinlich keine homogène Population dar, da die Langerhanszellen, die früher übarall in den epidermalen Anhangsgebilden nachgewiesen wurden, bei Acetylcholinesterase-Färbung nur in der Epidermis zu finden waren. Nach einer Orf-Virus-Infektion formiert sich eine dichte Masse aus eng verbundenen Klasse II+-Dendritenzellen in der betroffenen nekrotisierenden Dermis unmittelbar neben den infizierten Haarfollikeln und unter der infizierten, degenerierenden Epidermis. Diese Zellen stehen untereinander in Verbindung und bilden anscheinend eine Barrière gegen die Invasion, ein Gorüst für die Immunabwehr und einen Ausgangs punkt für die anschließenden Reparaturvorgänge in der Epidermis. Sie scheinen als Basis eines hochentwickelten lokalen Abwehrsystems der Haut zu fungieren. Resumen Células dendríticas de class II+ se observaron en gran cantidad en la piel de la oveja especialmente en dos localizaciones: a) en la epidermis, en la dermis muy próxima a la epidermis y en anejos cutáneos y b) en las proximidades de los vasos sanguíneos. No parece tratarse de una población homogénea de células puesto que las células de Langerhans, que previamente se habían encontrado en los anejos epidérmicos, se encontraron únicamente en la epidermis utilizando técnicas de detección del acetilcol-inesterasa. Después de la infección con el virus del ectima contagioso ovino se observó una masa de células dendríticas de clase II, dispuestas de forma muy densa, en las proximidades de la dermis necrosada y de los folículos pilosos y de la epidermis infectada. Eatas células interaccionan entre si y parecen formar una barrera contra la invasión, una red inmunitaria de defensa y participar en la reparación de la epidermis; parece ser que esta población de células dendriticas son la base de un sistema de defensa dérmico local altamente integrado.     

Vitamin deficiencies in cattle

Deficiencies of vitamins A, D, K, E and thiamin can cause severe limitations in beef production. In particular, vitamin A and E can be common causes of lost profit, secondary to limitations of reproductive and growth potential. Prolonged dry periods will reduce available A and E in pasture forage, as can ensiling and prolonged storage of harvested feedstuffs. Polioencephalomalacia is a thiamin responsive disorder, associated with high concentrate feeding and lush pastures. Antimetabolites, such as amprolium, will cause thiamine deficiency when fed in excess. Recent information has shown improved performance with supplemental beta carotene and niacin. The positive responses in reproductive performance, noted with cattle fed supplemental beta carotene, was independent of vitamin A. Supplementation of vitamins above National Research Council recommendations can be justified. However, proper evaluation of feed and animal status, and documentation of a response to supplementation is necessary before diagnosing deficiencies of specific nutrients.     

In situ hybridization analysis of ovarian prostaglandin endoperoxide synthase mRNA throughout the periovulatory period of the ewe.

Cellular alterations in level of expression of mRNA encoding for prostaglandin endoperoxide synthase were quantified within ovarian tissues of sheep obtained before, during and after induction of the preovulatory surge of LH and ovulation with LHRH. This was accomplished by isotopic in situ hybridization using a selective cRNA probe to ovine prostaglandin endoperoxide synthase mRNA. A significant elevation in mRNA was detected within the theca interna of the preovulatory follicle at 8, 16 and 24 hr following administration of LHRH. Very close to the time of ovulation (ie., at 24 hr post-LHRH) a marked rise in mRNA was observed in association with epithelial cells covering the apical surface of the follicle. Ovarian cyclooxygenase metabolites of arachidonic acid produced during the ovulatory process in the ewe originate within the thecal layer and germinal epithelium of the follicle destined to ovulate.     

Salmonella contamination of poultry flocks in The Netherlands

The contamination of poultry in the Netherlands with Salmonella enteritidis was tested. For this, different methods (detection of S. enteritidis in faecal samples of 25 g; detection of S. enteritidis in cloacal swabs; detection of S. enteritidis by serological testing of antibodies in serum) were compared for their efficiency to detect S. enteritidis in flocks of poultry. Testing of faecal samples clearly yielded the best results. This method was used in a transmission study, in which 14 flocks descending from a contaminated primary mother flock were screened for the presence of S. enteritidis. The method was also used for screening 49 flocks of laying hens and 52 flocks of broiler chickens throughout the Netherlands. From the transmission study it became clear that S. enteritidis, phage type 2 (Dutch phage set) was isolated both from the mother flock and from five of the descendent flocks. Screening of poultry flocks for the presence of salmonella revealed that salmonella was present in 47% of the layer flocks and in 94% of the broiler flocks. S. enteritidis was isolated from 15% of the flocks screened.