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Biomedical subjects

J Fabricant

Publications and source records attributed to J Fabricant.

At least 37 records · Page 2Linked to original sources
PubMed1971

Identification of Mycoplasmatales: procedures for both characterization and purification.

Procedures with potential value for identification and purification of Mycoplasma were applied to over 240 cultures representing 11 of the 12 known avian serotypes. Growth was tested at pH 5.5 and 9.5, at 25 and 42 C, in serum-free media, and in the presence of (i) 1% bile salts, (ii) 3% NaCl, and (iii) 0.02% methylene blue. One avian Mycoplasma serotype grew in broth containing 1% bile salts. Two of 11 avian serotypes were resistant to 0.02% methylene blue. A number of Mycoplasma strains grew at 42 C or in a pH 9.5 medium. Usefulness of these procedures for purifying cultures of Mycoplasma is discussed.

Agar↗
PubMed1971

Identification of Mycoplasmatales: characterization procedures.

A large collection of avian Mycoplasma cultures was used in studies to improve and develop biological and biochemical characterization techniques. Differential patterns among 11 avian serotypes were shown by carbohydrate fermentation, tetrazolium- and methylene blue-reduction reactions, breakdown of arginine, and the formation of film on egg yolk-agar. Some cultures fermented as many as 14 carbohydrates. Polyhydric alcohols and pentoses were among the compounds fermented. An improved procedure for determining methylene blue reduction by Mycoplasma was developed. These simple, rapid procedures are reproducible and should be useful in grouping Mycoplasma isolates prior to definitive identification by serological or other means.

Agar↗
PubMedDate not supplied

Rous sarcoma regression in chickens resistant or susceptible to Marek's disease.

In 4 experiments, strains of chickens relatively susceptible (S-strain, P-line) or resistant (N-line, PDRC) to Marek's disease (MD) were challenged with Rous sarcoma virus (RSV) at 6-8 weeks old. RSV tumors occurred in 94-100% of the birds in each strain, but the number with tumors that regressed during the 40-46-day experiment varied from 7% (S-strain) to 91% (PDRC). The N-line and P-line birds, derived from a random-bred flock with selection only for susceptibility or resistance to MD, regressed their tumors at about equal rates (respectively 59 and 65%). Thus, although the genetic strains differed in ability to regress RSV tumors, the difference was not necessarily related to genetic resistance or susceptibility to MD. Other birds in 2 of the experiments, infected 2-4 weeks earlier with JM or GA isolants of MD virus, had significantly (P less than 0.01) lower incidence of RSV tumor regression than did controls provided that they developed gross lesions of MD.

Animals↗
PubMedDate not supplied

A fluorescent-antibody study of the pathogenesis of infectious laryngotracheitis.

A study of the pathogenesis of infectious laryngotracheitis (ILT) by the fluorescent-antibody (FA) technique in birds inoculated ocularly, intratracheally, by vent brush, and by aerosol revealed that the epithelium of the conjunctiva and respiratory tract are the tissues actively infected by natural routes of infection. The virus propagated at the sites of initial exposure but there was no evidence of spread by viremia. Viral antigen was detected 2-7 days postexposure and rarely thereafter. Birds infected intratracheally showed intense infection in the nasal turbinates, suggesting that high concentrations of virus were expelled as an aerosol from infected tracheas. Virus applied to the dorsal lip of the vent by drop or brush was rapidly transferred mechanically to the bursa of Fabricius; the epithelial lining between follicles and between follicular cortex and medulla was positive in FA tests 48-72 hours postexposure.

Aerosols↗
PubMedDate not supplied

Pathogenicity of low-virulence Marek's disease viruses in normal versus immunologically compromised chickens.

To learn whether "low virulence" isolants of Marek's disease (MD) virus have a low inherent oncogenic potential, 3 isolants (CU-1, CU-2, S-11) were given to genetically susceptible S-strain or P-line birds with or without immunosuppressive treatments. Based on lesion incidence and type during an 8-10-week experimental period, embryonal (17-day) bursectomy and neonatal cyclophosphamide (CY) treatment were without effect on CU-1 and CU-2 infections in P-lines. S-11 virus was virulent for P-lines, and CY treatment reduced MD incidence as reported by others for virulent virus infections. Neonatal thymectomy or infection in ovo (at 8 days of incubation) or use of the more susceptible S-strain chicks all increased the incidence of MD induced by CU-1 and CU-2 viruses. It was concluded that the "low virulence" of these viruses is a reflection of an adequate immune response by the host.

Animals↗
PubMedDate not supplied

Tissue tropism of three cloacal isolates and Massachusetts strain of infectious bronchitis virus.

Three virus isolates (ECV-1, -2, and -3) recovered from cloacae of chickens in flocks that experienced drops in egg production were identified as infectious bronchitis virus (IBV), based on characteristic embryo lesions, chloroform sensitivity, coronavirus morphology, and serology. Because these isolates were recovered from the cloacae of the hens, their tissue tropism was compared with the prototype strain of IBV, Massachusetts-41 (M-41), in experimentally inoculated chickens. During the 39-day period postinoculation (PI), virus isolation was attempted from digestive and respiratory tracts, kidney, and cloacal swabs. ECV-1, ECV-2, and M-41 were more frequently recovered from the cecal tonsils than from other tissues. ECV-1, ECV-3, and M-41 were also recovered from kidney for up to 39 days PI. ECV-2 and ECV-3 had a limited distribution in respiratory tissues, being isolated only sporadically from trachea, bronchus, and lung. Surprisingly, ECV-2 was isolated from esophagus at 2, 16, 30, and 39 days PI; otherwise, its distribution in other tissues was sporadic. Results confirmed that IBV, including M-41, can infect a variety of tissues and that some isolates may be recovered frequently from digestive tract tissues, particularly from the cecal tonsils.

Animals↗
PubMedDate not supplied

Indications of immunodepression in chickens infected with various strains of Marek's disease virus.

The effect of infection by various strains of Marek's disease virus (MDV) on the immune function of 3-week-old chickens was examined. MDV strains of low (CU-2, RB-7) and high (RB-3, MD-5, and MD-11) pathogenicity were compared with prototype JM-10 strain of moderate pathogenicity. Mortality, whole body weight, relative weights of lymphoid organs, histopathology, humoral antibody responses to thymus-dependent and -independent antigens, and in vitro lymphocyte responses to mitogen stimulation were investigated at 1, 2, and 3 weeks postinfection. MDV strains of high pathogenicity significantly depressed responses at 3 weeks postinfection, seeming to indicate the ability of these viruses to induce severe immunodepression. However, the fact that the moderately pathogenic and even some of the low-pathogenicity strains induced immunodepression suggests that other viral mechanisms are also important in its determination.

Animals↗