Humoral immune responses of cats to feline leukemia virus: comparison of responses to the major structural protein p30 and to a virus-specific cell membrane antigen (FOCMA).

Radioimmunoprecipitation was used to test cat sera for ability to bind to the purified major internal protein p30 of feline leukemia viurs (FeLV), to the endogenous cat virus (RD-114), and to murine leukemia virus (MuLV). The data were compared with results of tests for antibody to the feline oncornavirus-associated cell membrane antigen FOCMA and for the presence of viremia. In contrast to the general lack of free antibody to FeLV p30 in a random sample of healthy cats, high levels of antibody to FeLV p30 and FOCMA were found in normal animals from high-leukemia-cluster households. Titers of greater than or equal to 200 for p30 and greater than or equal to 32 for FOCMA were found in nonviremic animals; a percentage of animals with high FOCMA titers and lower or no p30 binding activity were viremic. Animals with neoplasms were low or negative for FOCMA antibody and did not have high titers of free p30 antibody. The p30 binding activity could be divided into three main categories: high binding with FeLV p30 and much lower activity with RD-114 and MuLV p30's, as seen with hyperimmune sera; high binding with FeLV and RD-114 p30's and low activity with MuLV p30, possibly indicative of specific antibody to both of the aforementioned proteins; and low level binding to all three p30's.     

Reaction and response times for accommodation

Using an infra-red dynamic optometer, a qualitative comparison of the accommodation responses of two observers to step changes in target position showed marked differences in their ability to accommodate correctly. Measurement of reaction time (or latency) gave results comparable with those of other workers and independent of target position. Measurements of response time showed for one observer that the response time was dependent on the extent of the accommodative change required; this was not true of the other observer. Possible reasons for the intersubject differences and the role of the instructions given to the observer are discussed.     

The opitcal system of the goldfish eye

Experiments are described in which the parameters of the various optical components of the eyes of both living and dead fish were measured. The results are used to construct a schematic eye for the goldfish; this then forms the basis of a discussion of various aspects of the goldfish visual system.     

Leukemia following Reye's syndrome treated with exchange transfusions: Search for type-C viral infection

A 5-year-old child developed acute lymphoblastic leukemia during convalescence from an episode of Reye's syndrome that was treated with multiple exchange transfusions. Routine laboratory, histology, and viral serology were unable to establish a common etiology for the 2 illnesses. Cultural and immunologic methods to search for evidence of infection with type-C viruses or viral genes in lymphoblasts from the buffy coat and bone marrow failed to reveal these agents. Although no common infectious etiology was defined for the close temporal occurrence of 2 rare diseases, the possibility of an iatrogenically induced malignancy was considered.     

Theoretical effect of changes in entrance pupil magnification on wavefront-guided laser refractive corneal surgery

PURPOSE: To explore theoretically the effect on the correction of higher order aberrations of changes in the magnification between the aperture stop (iris) and entrance pupil of the eye, following myopic excimer laser ablation. METHODS: Using a simple schematic eye model, paraxial calculations were made of the position and magnification of the entrance pupil of the eye as a function of the power of a myopic photorefractive keratectomy correction. RESULTS: Corneal flattening following myopic corneal ablation results in a reduction in the magnification between the aperture stop (iris) and entrance pupil. This implies that an ablation designed to correct higher order errors on the basis of the preoperative wavefront aberration across the entrance pupil will result in an incomplete correction. Taking into account the fact that the total ocular aberration depends on the combined effects of all optical components of the eye, which are distributed in depth, rather than being associated simply with the anterior surface of the cornea, the exact effects depend on the methods used to measure the aberration and the distribution of the total aberration between the different components of the eye. The errors in correction increase with the magnitude of the myopic correction. CONCLUSIONS: To minimize the postoperative higher order aberrations in higher amounts of myopia, it may be desirable to remeasure them after a first ablation to correct the second-order refractive errors and then to carry out a second ablation to correct the higher order aberrations.     

Discovery of Novel Benzo[a]phenoxazine SSJ-183 as a Drug Candidate for Malaria

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