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Biomedical subjects

S Ullman

Publications and source records attributed to S Ullman.

At least 109 records · Page 6Linked to original sources
PubMed1982

Deposits of complement and immunoglobulins in vessel walls in pyoderma gangrenosum.

Previous immunofluorescence studies on pyoderma gangrenosum (PG) proved negative. Biopsies from the ulcer edge of 8 patients with PG were examined by immunofluorescence microscopy. Deposits of complement C3 were seen in the vessel walls of all samples, IgM in three and IgA in one. Granular deposits of C3 were seen at the dermal--epidermal junction in 2 patients. Biopsies from clinically normal skin of 6 of the patients were negative. It is suggested that deposition of immune complexes in the dermal vessel walls may play a role in the pathogenesis of PG.

Blood Vessels↗
PubMed1982

The lupus band test as a measure of disease activity in systemic lupus erythematosus.

One hundred twenty-seven biopsy specimens from clinically normal light-protected skin of 88 patients with active and inactive lupus erythematosus (LE) were examined for deposits of IgG, IgM, IgA, and C3 at the dermal-epidermal junction (DEJ). Deposits were found in 91% of those with active disease and in 33% of those with inactive disease. The finding of such deposits reflected active disease just as did a decrease in serum C3 and C4 levels, elevated anti-double-stranded DNA, the presence of LE cells, lymphopenia, and an elevation of the ESR. The presence or absence of deposits in repeated biopsy specimens indicated changing disease activity, as estimated clinically, just as did changes in the other variables mentioned. Neither immunoreactants in skin nor any other laboratory abnormality reflected renal disease or other type of organ involvement. Deposits of IgG were not more commonly found in patients with renal disease.

Complement C3↗
PubMed1981

Directional selectivity and its use in early visual processing.

The construction of directionally selective units, and their use in the processing of visual motion, are considered. The zero crossings of delta 2G (x,y) * I(x,y) are located, as in Marr & Hildreth (1980). That is, the image is filtered through centre-surround receptive fields, and the zero values in the output are found. In addition, the time derivative delta[delta 2G(x,y) * I(x,y)]/delta t is measured at the zero crossings, and serves to constrain the local direction of motion to within 180 degrees. The direction of motion can be determined in a second stage, for example by combining the local constraints. The second part of the paper suggests a specific model of the information processing by the X and Y cells of the retina and lateral geniculate nucleus, and certain classes of cortical simple cells. A number of psychophysical and neurophysiological predictions are derived from the theory.

Animals↗
PubMed1981

Deposits of immunoglobulins, complement, and fibrinogen in oral lupus erythematosus, lichen planus, and leukoplakia.

Direct immunofluorescent staining (IF) for detection of deposits of IgG, IgM, IgA, complement C3, and fibrinogen at the basement membrane zone has been performed on a total of 279 biopsy specimens from oral lesions and clinically normal oral mucosa from the following groups of patients: fourty-five discoid lupus erythematosus (DLE), including sixteen patients without skin lesions, seven systemic lupus erythematosus (SLE); fourty-five lichen planus (LP); thirty leukoplakia (Leuk.); twenty patients with uncertain diagnosis, termed DLE? LP?; and twenty-three healthy persons. Deposits of immunoglobulins (lg) occurred in 73 percent of oral lesions in DLE and in 100 percent of the oral lesions in SLE, whereas lg deposits occurred in 3 to 30 percent in the other groups, the differences being significant (P less than 0.05). It is concluded that lg deposits are a characteristic feature of oral lesions of DLE and SLE and only rarely occur in oral lesions of LP and Leuk., which are the most important differential diagnoses. A direct immunofluorescence test on oral lesions suspected to be LE should be regarded as positive only if lg deposits are present, since C3 occurs frequently in oral lesions other than LE. Consideration can be given to the inclusion of lg deposits in the diagnostic criteria for oral LE lesions.

Adolescent↗
PubMed1980

The effect of similarity between line segments on the correspondence strength in apparent motion.

The correspondence between line segments in apparent motion is shown to be affected by the similarity between them. Increase in orientation difference or in length ratio between lines in a competing motion configuration decreases the probability of perceived apparent motion between them. The results suggest the existence of a built-in preference metric that may reflect a measure of matching likelihood between elements in three-dimensional space.

Distance Perception↗
PubMed1980

Deposits of immunoglobulin and complement in psoriatic lesions.

Biopsy specimens from 43 patients with psoriasis were studied by immunofluorescence microscopy. Deposits of complement C3 and/or immunoglobulins were seen in the vessel walls and/or in the dermal-epidermal junction of all of 21 patients with pustular psoriasis, acute guttate psoriasis, psoriatic arthropathy and erythroderma. similar deposits were seen in nine out of 22 patients with psoriasis vulgaris. Deposits were found in clinically uninvolved skin in only one of 37 patients. The results might suggest that the deposition of immune complexes in the vessel walls are of importance for the development of psoriatic lesions.

Complement C3↗
PubMed1979

The interpretation of structure from motion.

The interpretation of structure from motion is examined from a computional point of view. The question addressed is how the three dimensional structure and motion of objects can be inferred from the two dimensional transformations of their projected images when no three dimensional information is conveyed by the individual projections. The following scheme is proposed: (i) divide the image into groups of four elements each; (ii) test each group for a rigid interpretation; (iii) combine the results obtained in (ii). It is shown that this scheme will correctly decompose scenes containing arbitrary rigid objects in motion, recovering their three dimensional structure and motion. The analysis is based primarily on the "structure from motion" theorem which states that the structure of four non-coplanar points is recoverable from three orthographic projections. The interpretation scheme is extended to cover perspective projections, and its psychological relevance is discussed.

Computers↗
PubMed1979

Bandpass channels, zero-crossings, and early visual information processing.

Under appropriate conditions zero-crossings of a bandpass signal are very rich in information. The authors examine here the relevance of this result to the early stages of visual information processing, where zero-crossings in the output of independent spatial-frequency-tuned channels may contain sufficient information for much of the subsequent processing.

Humans↗
PubMed1979

Deposits of immunoglobulins and complement in skin of patients with rheumatoid arthritis. Influence of anti-rheumatic treatment.

Immunopathological studies on skin biopsies from 88 patients with rheumatoid arthritis showed that one-third of them had deposits of IgM and/or C3 in the walls of small vessels immediately underneath the dermal-epidermal junction. The deposits in the vessel walls which may reflect subclinical immune complex vasculitis could be correlated to the occurrence of IgG-rheumatoid factor in the serum, but not to IgM-rheumatoid factor, other extra-articular manifestations, or to the occurrence of circulating immune complexes demonstrated by the complement consumption test or the thrombocyte aggregation test. Two untreated patients had granular deposits in the dermal-epidermal junction. Five out of 50 patients developed deposits in the dermal-epidermal junction during treatment with levamisole, penicillamine, or azathioprine, as observed by serial skin biopsies.

Anti-Inflammatory Agents↗
PubMed1978

Two dimensionality of the correspondence process in apparent motion.

A fundamental process underlying motion perception is the matching of corresponding elements in different views. In this correspondence process spatial separation between elements plays a major role. The relevant separation is shown by the current study to be the two-dimensional, uninterpreted distance, a finding that has an implication to the level at which the correspondence process is carried out. The current findings are compared with earlier results concerning 'optimality' of apparent motion to conclude that optimality cannot serve as a measure for the correspondence strength.

Depth Perception↗
PubMed1978

Penicillamine-induced polymyositis-dermatomyositis.

Two patients with classical rheumatoid arthritis developed myopathy during treatment with penicillamine. In both patients, electromyography and muscle biopsies were indicative of polymyositis. In one patient, muscle enzymes were not examined at the appropriate time; in the other patient muscle enzymes were raised. This latter patient also had a rash and, in the dermal epidermal junction of pathological skin, granular deposits of immunoglobulin and complement were found. The myopathy subsided in both patients after withdrawal of penicillamine.

Action Potentials↗
PubMed1978

Deposits of complement and immunoglobulins in dermal and synovial vessels in psoriasis.

Deposits of complement C3 and/or immunoglobulin were found in the vessel walls and/or at the dermal-epidermal junction in skin lesions of all of 11 patients with psoriatic arthritis and guttate psoriasis. Similar deposits were seen in 6 out of 15 patients with psoriasis vulgaris. Synovial tissue available from 2 patients revealed deposits in the vessel walls.

Complement C3↗
PubMed1978

Levamisole-induced hypersensitivity.

A 73-year-old woman with rheumatoid arthritis was treated with Levamisole, 150 mg per day, on 2 days a week. Her arthritis improved, but she developed a severely itching rash, and the treatment was stopped after 6 months. Penicillamine was subsequently given and tolerated without skin complications. 15 months after regular Levamisole was stopped, she was given a single dose of 150 mg which provoked fever of 40 degrees C and rash. Thirteen punch-biopsy specimens were examined by direct immunofluorescence microscopy. During the Levamisole treatment, granular deposits of IgG and C3 were found at the dermal--epidermal junction. Subsequently, the deposits disappeared, but reappeared after Levamisole challenge. The patient's leukocytes were exposed in vitro to Levamisole, and 36% of the total histamine content in the basophils was released. Our results provide further evidence that Levamisole can cause type-I as well as type-III hypersensitivity.

Aged↗