Biomedical subjects

M Malkinson

Publications and source records attributed to M Malkinson.

62 records · Page 4Linked to original sources

PubMedDate not supplied

Marek's disease in turkeys. I. A seven-year survey of commercial flocks and experimental infection using two field isolates.

Marek's disease virus (MDV) causes immunosuppression and tumors in chickens, but the turkey is an unusual host for the virus, and tumors caused by MDV in turkeys are unique. We describe the prevalence of turkey tumors in Israel between 1993 and 2000, their molecular diagnosis by polymerase chain reaction (PCR), and the natural distribution of herpesvirus of turkeys (HVT). Most clinical cases with tumors in commercial turkeys were diagnosed as MDV. The reproduction of Marek's disease (MD) in turkeys by two turkey MDV strains, Ar and La, was analyzed, and it was shown that these strains can induce tumors in experimental trials. The severity of experimental disease differed from those features of the original outbreak, since a less severe disease was recorded.

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PubMedDate not supplied

Marek's disease in turkeys. II. Characterization of the viral glycoprotein B gene and antigen of a turkey strain of Marek's disease virus.

Marek's disease virus (MDV) causes immunosuppression and tumors in chickens. As sporadic cases of Marek's disease (MD) were recorded in turkeys, the antigenic and genomic characteristics of the MDV glycoprotein B (gB) gene and antigen of turkeys were compared to the chicken MDV gB. The whole chicken and turkey gB genes were sequenced and found identical. By immunoblotting of infected-cell culture lysates using chicken convalescent and gB monoclonal antibodies, the antigenic epitopes of the chicken and turkey viruses were found to differ. The turkey MDV had a unique epitope, compared to the chicken MDV and compared with our previous findings. While the chicken MDV had two epitope types, heat-labile but dithiothreitol (DTT)-stable and heat-stable but DTT-labile, the turkey MDV gB epitope is both heat and DTT-labile.

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PubMedDate not supplied

Chronic lesions in geese photosensitized by Ammi majus.

Chronic lesions of the beak, footweb, and eye of geese photosensitized by the comsumption of Ammi majus (L.) are described, 7 weeks after the acute symptoms commenced. Sixty-four (48%) of the 133 birds in the flock showed various degrees of abnormality. All affected birds had stunting of the upper beak and cicatrization and thickening of the footweb. Eighty-nine percent of the affected birds showed ocular involvement, comprising chemosis, blepharoconjunctivitis, keratitis, symblepharon, ankyloblepharon, cicatricial ectropium, and mydriasis.

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PubMedDate not supplied

Enzyme immunoassay studies on the serological response of turkeys to hemorrhagic enteritis virus.

An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of antibodies in turkey serum to hemorrhagic enteritis virus. The ELISA antigen was extracted from turkey spleens and partially purified with fluorocarbon. Antibodies were demonstrated in serum samples of breeding and meat flocks that had been naturally exposed to infection. These samples were also examined in parallel by agar-gel precipitin (AGP); most of the sera were AGP-positive. ELISA, however, was more sensitive in detecting antibodies in day-old sera that were AGP-negative. The passively acquired antibodies were no longer detected by 4 weeks of age. A brisk but short-lived secondary response was detected by ELISA in the sera of turkeys immunized with beta-propiolactone-inactivated extract of infected spleens.

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PubMedDate not supplied

Efficacy of pralidoxime iodide and obidoxime dichloride as antidotes in diazinon-poisoned goslings.

The antidotal efficacy of pralidoxime iodide and obidoxime dichloride was investigated in goslings poisoned by a supralethal dose of the organophosphorus insecticide diazinon. Various doses of both drugs were administered by intramuscular injection when the poisoned birds were unable to walk. Pralidoxime at 100 mg/kg brought about a complete and speedy clinical recovery. Fifty mg/kg induced recovery in 4 of 6 poisoned goslings, and 25 mg/kg successfully trated only 1 of 6 birds. Obidoxime at 25 mg/kg showed no therapeutic properties whereas 50 and 100 mg/kg delayed the death of some birds by several hours. At 100 mg/kg, all goslings had transient signs of intoxication, which precluded the use of this compound as an antidote at higher doses. The mode of action of these antidotes in diazinon-poisoned goslings is discussed.

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PubMedDate not supplied

Applications of the polymerase chain reaction to detect infectious bursal disease virus in naturally infected chickens.

Reverse transcriptase-polymerase chain reaction was used for identification of Israeli isolates of infectious bursal disease virus (IBDV). The system was applied to tissue culture and to bursa of Fabricius from infected chickens; these latter samples had been frozen for as long as 4 years. From base homology analysis of published sequences of serotype 1 IBDV, two pairs of primers, targeted to amplify sequences from the VP2 and VP3 cistrons, were prepared. The two sets of primers could detect viruses of serotype 1. The primers directed to the cistrons could detect viral sequences from seven infected chickens. No reaction was detected with RNA extracted from bursal cells of healthy chickens or from uninfected cells. The sensitivity of the reaction was equivalent to 2.5 x 10(1) TCID50.

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PubMedDate not supplied

Efficacy of norfloxacin nicotinate treatment of broiler breeders against Haemophilus paragallinarum.

The efficacy of the antimicrobial drug norfloxacin for treating infectious coryza was examined in 26-week-old male broiler breeders. Chickens were inoculated in the infraorbital sinus with the causal organism, Haemophilus paragallinarum. Four experimental groups were set up: control uninfected chickens, infected untreated chickens, and infected chickens treated for 5 days with either 20 mg norfloxacin/kg body weight or 40 mg norfloxacin/kg body weight. The first clinical signs were seen 24 hr postinfection. Of the observed clinical signs, sinus edema was ameliorated by the treatment, and the percentage of birds presenting sinus edema, sneezing, and increased lacrimation was significantly reduced after treatment. Clinical signs disappeared rapidly and were gone by the second day of treatment. The other signs disappeared gradually over 2 weeks after treatment began. There were no significant differences between the two dosage levels. H. paragallinarum was not reisolated from the infected infraorbital sinuses of birds treated with the higher dose of the drug, whereas the reisolation rate was 17% from those treated with the lower dose and 86% from the infected untreated birds.

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PubMedDate not supplied

Causes of losses including a Borna disease paralytic syndrome affecting young ostriches of one breeding organization over a five-year period (1989-1993).

Necropsy records and causes of mortality of ostriches up to 3 months old over a 5-year period (1989-1993) are presented. The data relate to one ostrich enterprise that comprises 10 breeding flocks, five rearing farms, and one hatchery. Causes of mortality are classified into nine major categories. The annual mortality percentages of all hatched ostriches over the 5-year period were 61%, 58%, 30%, 29%, and 16.6%, and the most significant cause of death was a paresis syndrome that accounted for 20%, 11%, 16%, 10.1%, and 2% mortality, respectively. Limb deformities and gastroenteritis were the other principal specific causes of mortality. The paresis syndrome was caused by an agent serologically related to Borna disease virus. Brain extracts from paralyzed ostriches, when given orally or intramuscularly to 5-week-old birds, reproduced the clinical signs and microscopic lesions. The mean time to death was less than 3 weeks for the intramuscularly infected group and was almost twice as long for the orally infected group.

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