Contrast sensitivity in humans with abnormal visual experience.

1. Grating contrast sensitivities have been determined over a range of spatial frequencies for a normal subject and for subjects who are visually biased in that they have a lower resolution capacity for targets of specific orientations. The bias si only found in astigmatic subjects and the grating orientation yielding poorest acuity coincides with the most defocused astigmatic meridian. However this resolution anisotropy remains when optical factors are accounted for. 2. For the normal subject, high and low frequency attenuation is found and a typical reduction in contrast sensitivity is exhibited for oblique target orientations. 3. The biased subjects, called meridional amblyopes because they have reduced acuity for a given grating orientation, show markedly abnormal contrast sensitivity functions. Their cut-off spatial frequencies are different for various target orientations and this difference applies also to contrast sensitivity over nearly the entire spatial frequency range tested (0-5-16 cycles/deg). The differences are of about the same magnitude for most frequencies and they are found in all types of meridional amblyopes. 4. Optical explanations of these differences are ruled out by laser-interference fringe tests and by varying effective pupil size. 5. Theoretical effects of defocus have been calculated to compare predicted visual deprivation with performance. Results indicate that reduced contrast sensitivity functions can be equivalent to a small defocus effect. 6. To examine the results in the spatial domain, inverse Fourier transforms of representative contrast sensitivity functions have been computed. The optical portion of the resulting spatial weighting functions has been parcelled out to obtain neural spatial weighting functions.     

Quantification of antibodies to the C3d subcomponent of human C3.

Purified soluble C3d has been employed to measure the concentration of anti-C3d antibodies in immune rabbit sera. Multiple batches of C3d, prepared from C3-C3b substrate by treatment with C3b-inactivator (KAF), after labelling with 125I, retained 80% immunoreactivity, and were stable on storage at -50 degrees and +4 degrees. Concentrations of anti-C3d were determined by Scatchard analysis of equilibrium concentrations of bound and free C3d in a mixture of 125I-labelled C3d and anti-C3d. Separation of bound from free C3d was by G-75 Sephadex filtration. Assuming a 1:1 molar ratio in the antibody-C3d complex, anti-C3d antibody concentrations for four rabbit whole antisera and four IgG preparations fell in the range 288-2433 microgram/ml, with Ko values of 6-2 X 10(8)-2-9 X 10(9) litres/mol. One commercial antiglobulin-serum contained 3-6 microgram anti C3d/ml and had a Ko value of 1-7 X 10(8) litres/mol. Values for anti-C3d concentrations measured independently by an indirect method employing 125I-labelled sheep anti-rabbit IgG averaged 20% lower than those obtained with 125I-labelled C3d. Antibody concentrations were correlated with antiglobulin agglutination titres against C3d-coated red cells; a titre of 1 was given by an anti-C3d concentration of 0-5 microgram/ml.     

Semantic relatedness effects in conjoined noun phrase production: implications for the role of short-term memory

Speech error data and empirical studies suggest that the scope of planning is larger for semantic than for phonological form representations in speech production. Previous results have demonstrated that some patients show dissociable impairments in the retention of semantic and phonological codes. The effect of these STM deficits on speech production was investigated using a phrase production paradigm that manipulated the semantic relatedness of the words in the phrase. Subjects produced a conjoined noun phrase to describe two pictures (e.g., "ball and hat") or produced the same phrases in response to pairs of written words. For the picture naming condition, control subjects showed an interference effect for semantically related pictures relative to unrelated pictures. This interference effect was greatly exaggerated for two patients with semantic short-term memory deficits but not for a patient with a phonological STM deficit. For the written words, control subjects showed a small facilitatory effect for the onset of phrases containing semantically related words. One of the patients with a semantic STM deficit who was tested on picture naming was also tested on these materials and showed a small facilitatory effect within the range of controls. The findings support the contention that speech planning is carried out at a phrasal level at the lexical-semantic level and that the capacities that support semantic retention in list recall support speech production planning.     

Quality control of storage phosphor digital radiography systems

Quality control (QC) of storage phosphor devices is important in assuring that the image information entered into an Image management and communication (IMAC) system is sufficient for diagnosis. QC of storage phosphor digital radiography systems is complex because of the self-corrective nature of the image-processing software used in these machines. Currently, one must produce hard copy to perform adequate QC. Inspection of images with reject analysis and inspection of cassettes and imaging plates has helped us in our QC program. For those QC tests using control limits, the appropriate settings for these limits are unknown. Starting approximations are given. Recommended tests are described.     

rIFN-γ-mediated growth suppression of platinum-sensitive and -resistant ovarian tumor cell lines not dependent upon arginase inhibition

The purpose of translational research is to test, in humans, novel therapeutic strategies developed through experimentation. Translational research should be regarded as a two-way road: Bench to Bedside and Bedside to Bench. However, Bedside to Bench efforts have regrettably been limited because the scientific aspects are poorly understood by full time clinicians and the difficulty of dealing with humans poorly appreciated by basic scientists. Translational research would be most useful to the scientific community at large if journals would foster specific interest for the publication of ex vivo human observation. The review process for such work should be assigned to clinical scientists competent not only in the intricacies of molecular or cell biology but also intimate with the reality of Internal Review Boards, ethics committees, Governmental Regulatory Agencies and most importantly the humane aspects of dealing with sick individuals and their families. This approach may focus both basic and clinical scientists and those struggling to fill the gap between them on the effective treatment of diseases affecting women, men and children making translational research more than an interesting concept.     

Thyrotropin-releasing hormone (TRH) counteracts neuronal damage induced by a substance P antagonist

Summary Intrathecal administration of the substance P antagonist Spantide caused marked necrotic changes of the gray matter of the spinal cord extending several segments from the injection site. Intravenous treatment with several doses of thyrotropin releasing hormone before and after Spantide injection completely prevented the necrotic lesion.     

EA rosette-forming lymphoid cells in chickens: specificity of the Fc receptor and its relationship to other surface antigens.

The receptor for erythrocyte-antibody (EA) complexes on the surface of chicken lymphoid cells was investigated using a rosette assay. The chicken EA receptor binds chicken immunoglobulin of the IgG class but not the IgM class. Binding to the EA receptor is dependent upon the Fc region of the immunoglobulin. No receptor for complement analogous to the mammalian C3b receptor was demonstrated on chicken lymphoid cells using the rosette assay. Inhibition studies utilizing immunoglobulins from several species demonstrated that chicken spleen cells do not bind mammalian immunoglobulin but may bind immunoglobulin of other avian species (turkey and duck) and a reptilian species (turtle). The chicken EA receptor is distinct from cell membrane bound immunoglobulin light chains, bursa-specific antigens and thymus-specific antigens. The receptor for EA complexes on chicken lymphoid cells is compared with the Fc receptor on mammalian lymphoid cells in the light of these observations.