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J K Davis

Publications and source records attributed to J K Davis.

At least 91 records · Page 5Linked to original sources

Control of Mycoplasma pulmonis infection in rats and mice: detection and elimination vs. vaccination.

Respiratory and genital mycoplasmoses, due to Mycoplasma pulmonis, are major intercurrent disease problems in laboratory rats and mice. Recent surveys indicate that M. pulmonis infection remains a common problem, not only in conventionally maintained colonies, but also in cesarean-derived, barrier-maintained animals. An enzyme-linked immunosorbent assay (ELISA) has been established for detection of anti-M. pulmonis IgG antibodies. When compared in extensive field test to other available diagnostic methods, the ELISA was found to be superior for routine diagnosis due to its sensitivity, specificity and rapidity, and there is no need for animal sacrifice, Ideally, detection via ELISA, elimination of infected animals, and prevention of reinfection by barrier housing is the best method for disease control. While this is a rational approach in production colonies and certain research stocks, it is impractical, if not impossible, in many research institutions due to current management practices. Thus, there is a critical need for alternative methods of control in these populations. Both rats and mice can be protected via immunization: therefore, vaccination appears to be a viable alternative. Remaining questions to be answered include: the most effective route of immunization, most effective immunogen, duration of protection, and vaccine efficacy in field use.

Animals↗

Immunofluorescent characterization of lymphocytes in lungs of rats infected with Mycoplasma pulmonis.

Immunofluorescence was used to determine the relative percentages of T and B lymphocytes found in the lungs of normal and Mycoplasma pulmonis-infected F344 rats. Lymphocytes recovered from controls were approximately 25% T, 25% B, and 50% unclassified mononuclear cells. Infected animals had a 2.6-fold greater number of T cells and IgA-bearing cells, and a 1.6-fold greater number of unclassified mononuclear cells. These studies show that M. pulmonis infection significantly alters lung lymphocyte populations both quantitatively and in subpopulation distribution. Therefore, future studies of rat lung lymphocytes should utilize animals known to be free of this ubiquitous respiratory pathogen.

Animals↗

Interactions between murine alveolar macrophages and Mycoplasma pulmonis in vitro.

In comparison to syngeneic fibroblasts, alveolar macrophages collected from Fischer 344 rats demonstrated a significant ability to decrease the growth rate of cell-associated Mycoplasma pulmonis, even in the absence of specific actimycoplasmal antibodies. However, when exposed to thallium acetate (a cytotoxic heavy metal), macrophages supported growth of mycoplasmas almost as well as did untreated fibroblasts. This suggests an active antimycoplasmal process operative in untreated macrophages. In contrast, mouse alveolar macrophages were not capable of exerting an antimycoplasmal effect unless rabbit anti-M. pulmonis antibodies were present. Paradoxically, mouse anti-M. pulmonis antibodies did not promote this effect.

Animals↗

Dear Dr. Eger.

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Eyeglasses↗

The dotting lens.

A dotting lens is an auxiliary lens placed in front of the telescope of a focimeter. It images a dot on the center of the lens under test on the scale in the eyepiece. A hole in the dotting lens permits simultaneous meaurement of the sample.

Contact Lenses↗

A polycarbonate ophthalmic-prescription lens series.

Improvements in polycarbonate material, production techniques, and scratch-resistant coatings, combined with a process-oriented design, have resulted in a precision lens series. Surface quality is comparable to that of untreated glass ophthalmic lenses. The repeatability of the process results in closely controlled axial power and off-axis performance. For most lens prescriptions, the ANSI Z80.1 optical-center specifications for prescription accuracy are maintained through a total field of view of 40 deg for an 8-mm range of center-of-rotation distances. Off-axis astigmatism is controlled for near-point seeing. The lenses are both lighter and thinner than those of crown glass. A scratch-resistant coating reduces the reflections normally associated with high-index (1.586) materials. Impact resistance exceeds that required by ANSI Z80.7 and is many times that required by ANSI Z80.1.

Carbonates↗

Protective effect of vaccination against Mycoplasma pulmonis respiratory disease in rats.

Intravenous vaccination of rats with either viable or Formalin-inactivated Mycoplasma pulmonis reduced the incidence and severity of lower respiratory tract lesions after intranasal challenge with viable organisms. Intranasal vaccination with killed organisms reduced the severity of rhinitis, but did not affect lesions in any other region of the respiratory tract. The maximum protection against upper tract lesions (rhinitis, otitis, and laryngotracheitis) was provided by intravenous immunization with viable organisms. Dual vaccination (intraperitoneal plus intranasal) with killed organisms provided no significant protection in any segment of the tract. However, these ineffective vaccine regimens did not potentiate the lesions. These results conclusively demonstrate that vaccination of rats against mycoplasma respiratory disease is feasible and also suggest that systemic vaccination may provide greater protection for the lungs than intranasal vaccination, at least when equivalent antigen doses are used.

Animals↗