Immunohistochemical detection of P-glycoprotein (PGP) and multidrug resistance-associated protein (MRP) in canine cutaneous mast cell tumors

Fifty-four canine cutaneous mast cell tumors were evaluated immunohistochemically for the expression of P-glycoprotein (PGP) and multidrug-resistance-associated protein (MRP). All tumors examined were graded according to the histological malignancy. ranging from grade I to III. The expression of PGP was confirmed in 15% (8/54) of whole, 33% (5/15) of grade I, 10% (3/31) of grade II, and 0% (0/8) of grade III tumors. The expression of MRP was found in 18% (10/54) of whole, 26% (4/15) of grade I, 19% (6/31) of grade II, and 0% (0/8) of grade III tumors. The cases positive to at least one of these 2 multidrug markers were 26%, 47%, 23% and 0% of whole and grade I to III tumors, respectively. These results indicate that at least 26% of canine cutaneous mast cell tumors express PGP and/or MRP and that these tumors may be resistant to several anti-cancer drugs.     

Methicillin-resistant coagulase-negative staphylococci isolated from healthy horses in Japan

OBJECTIVE: To determine patterns of methicillin-resistant staphylococci isolated from apparently healthy horses. SAMPLE POPULATION: 44 horses from 8 riding clubs in Japan. PROCEDURE: Methicill in-resistant staphylococci were isolated from the skin or nares, using a selective medium containing a beta-(symboric) lactam antibiotic, ceftizoxime. Clonality of isolates was determined by use of pulsed-field gel electrophoresis. Detection of mecA, mecl, and mecR1 genes was accomplished by use of polymerase chain reactions. RESULT: Of the 44 horses, 13 (29.5%) yielded 15 isolates of methicillin-resistant staphylococci. The 15 isolates were identified as 6 species (Staphylococcus epidermidis, S lentus, S saprophyticus, S xylosus, S sciuri, and S haemolyticus). However, methicillin-resistant S aureus was seldom isolated. Each isolate contained the mecA gene and had a high resistance to beta-lactam antibiotics. Some isolates also were resistant to other antibiotics such as erythromycin and kanamycin. CONCLUSIONS AND CLINICAL RELEVANCE: Methicillin-resistant coagulase-negative staphylococci that were highly resistant to various antibiotics were isolated from apparently healthy horses in Japan. These organisms must be considered a potential threat to horses and veterinarians who care for them.     

Reticuloendotheliosis virus (REV) long terminal repeats incorporated in the genomes of commercial fowl poxvirus vaccines and pigeon poxviruses without indication of the presence of infectious REV

Because of reticuloendotheliosis virus (REV) contamination in commercial poultry vaccines, polymerase chain reaction (PCR) assays have been described to increase the sensitivity of biological assays used to detect REV in vaccines. The PCR assay designed to amplify the long terminal repeat (LTR) region of REV identified REV LTRs in many of the commercial fowl poxvirus (FPV) vaccines evaluated. These commercial vaccines were not thought to be contaminated with replicating REV because of the lack of REV outbreaks, the lack of in vitro amplification, and lack of a serologic response to REV. As previously described, the FPV S vaccine strain is known to carry infectious integrated proviral REV, whereas FPV M vaccine strain and its derivatives carry integrated LTRs or remnants of REV proviral DNA inserted into the FPV genome. Another PCR assay designed to amplify the envelope gene of REV was used to verify that the envelope proviral gene was not present in REV LTR PCR-positive samples. Southern blot analysis with REV LTR probes hybridized to the 9-kb EcoRI genomic fragment of all FPV and pigeon poxviruses evaluated, whereas the envelope probe did not hybridize to any poxvirus genome. Sequence analysis of the 9-kb EcoRI fragment indicated that an integrated REV LTR exists in the 9-kb EcoRI of some poxvirus genomes. A new PCR assay designed to amplify integrated REV LTRs in the 9-kb EcoRI fragment identified complete and incomplete integrated REV LTRs in all FPV and pigeon poxvirus genomes evaluated.     

A morphometric study of foetal and newborn cardiac growth in the horse

A morphometric study of hearts in 81 equine foetuses, ranging in age from 190 to 330 days of foetal age, and in 26 newborn foals is reported. The mean weight, external dimensions, ventricular wall thickness and circumference of the atrio-ventricular orifice were measured. Features of the main associated vessels of the heart were also recorded. All cardiac measurements of foetuses increased linearly throughout the latter half of pregnancy and were highly correlated with foetal age. This linear growth pattern was also found in the parameters of the associated arterial trunks. The ratio of the right ventricular weight to the total ventricular weight in the equine foetuses increased gradually from 0.27 (Day 190) to 0.34 (full term), but in newborn foals, this ratio began to decrease soon after birth, declining from 0.32 to 0.28 by 11 days of age. The interventricular septum was thickest followed by the right ventricular wall, and the left ventricular wall was thinnest during the period of gestation studied. The right ventricle was 3.2 per cent to 31.5 per cent thicker than the left ventricle.     

Effect of Eimeria tenella infection on the caecal population of lincomycin-resistant Clostridium perfringens introduced into chickens

The effect of Eimeria tenella infection on the caecal population of lincomycin-resistant Clostridium perfringens (KGW 851) newly introduced into chickens was studied. Four groups of chickens consisted of: (1) Uninoculated controls; (2) inoculated with C perfringens (KGW 851); (3) inoculated with E tenella; and (4) inoculated with C perfringens (KGW 851) followed by E tenella. Five chickens in each group were necropsied on each of days 0, 3, 5, 7, 10 and 14 after the E tenella inoculation. The mean total C perfringens counts in the caecal contents increased at five days after E tenella inoculation and reached maximum counts at seven days after the inoculation. Also lincomycin-resistant C perfringens readily established itself at approximately one 10th of the total C perfringens population in the presence or absence of E tenella infection.     

Adsorption effect of activated charcoal on enterohemorrhagic Escherichia coli

The adsorption property of activated charcoal on verotoxin (VT)-producing Escherichia coli (VTEC) was examined using E. coli O157:H7. In the present study, E. coli O157:H7 strains were effectively adsorbed by activated charcoal. Adsorption was dose-dependent, and the maximum adsorption occurred within 5 min. At 10 mg of activated charcoal, bacteria tested were completely adsorbed. Activated charcoal also had the capacity to adsorb toxin (verotoxin 2) activity from the bacterial extract. Furthermore, the adsorption efficiency of activated charcoal for the normal bacterial flora in the intestine was assessed using Enterococcus faecium, Bifidobacterium thermophilum, and Lactobacillus acidophilus. Activated charcoal showed lower binding capacity to the normal bacterial flora tested than that to E. coli O157:H7 strains. These results suggest that activated charcoal could be a good adsorbent system for the removal of VTEC and verotoxin.