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Biomedical subjects

S Ullman

Publications and source records attributed to S Ullman.

At least 19 recordsLinked to original sources
PubMed1992

Low-level aspects of segmentation and recognition.

This paper discusses two problems related to three-dimensional object recognition. The first is segmentation and the selection of a candidate object in the image, the second is the recognition of a three-dimensional object from different viewing positions. Regarding segmentation, it is shown how globally salient structures can be extracted from a contour image based on geometrical attributes, including smoothness and contour length. This computation is performed by a parallel network of locally connected neuron-like elements. With respect to the effect of viewing, it is shown how the problem can be overcome by using the linear combinations of a small number of two-dimensional object views. In both problems the emphasis is on methods that are relatively low level in nature. Segmentation is performed using a bottom-up process, driven by the geometry of image contours. Recognition is performed without using explicit three-dimensional models, but by the direct manipulation of two-dimensional images.

Computer Simulation↗
PubMed1992

[Leprosy--still a possibility in Denmark].

A case of borderline tuberculoid leprosy in a 27 year old woman from the Philippines is presented. The diagnosis was made after repeated biopsies. Only a single mycobacterium was present and the histology of the initial biopsies was inconclusive. This case emphasizes that leprosy is still imported to Denmark, and that the diagnosis is often difficult and delayed for years.

Adult↗
PubMed1992

Clinical manifestations in patients with autoantibodies specific for nuclear lamin proteins.

IgG antibodies to nuclear lamin proteins have been found in serum samples from 31 patients using immunofluorescence on HEp-2 cells, Western blotting, and enzyme-linked immunosorbent assay, performed against a nuclear lamina preparation from Ehrlich ascites tumor cells. Antilamin antibodies were most prevalent among patients with nonerosive, seronegative polyarthritis, or patients showing serum antiphospholipid reactivity as well. It is possible that anti-lamin antibodies may thus be a marker for a subgroup of polyarthritis patients who have a different prognosis from that of those with seropositive rheumatoid arthritis. The mechanism for the combined occurrence of anti-lamin and antiphospholipid autoantibodies is obscure. Future studies will answer whether these two antibodies represent a distinct antibody profile in patients with antiphospholipid antibody syndrome.

Adolescent↗
PubMed1992

Lipoid proteinosis.

Lipoid proteinosis (Urbach-Wiethe disease) is a rare, recessively inherited disorder that is characterized by the deposition of hyaline-like material in the skin, oral cavity, and other tissues. It usually appears in infancy with hoarseness. We report a case of lipoid proteinosis in a 10-year-old boy that demonstrates the characteristic clinical, histologic, and ultramicroscopic features of this disease.

Child↗
PubMed1991

[Systemic lupus erythematosus. 1. Disease manifestations, infections, thrombotic episodes, causes of death and survival in a case load of 173 patients followed for 13.9 years].

One hundred and seventy-three patients had systemic lupus erythematosus according to the 1982-ARA-criteria. The mean disease duration at the time of the study was 16.4 years, and the patients were followed by three Copenhagen clinics for a mean of 13.9 years until 1987/88 or death. Half of the patients had nephropathy, 61 patients developed severe infections, and 39 patients had thrombotic episodes. Fifty-six patients died during the observation period, 24 due to active lupus (12 of kidney failure), 12 because of infections, and 11 because of atherosclerotic cardio-vascular disease. The patients had 10-, 15- and 20-year survival rates of 80, 65 and 48 per cent. The deaths were evenly distributed throughout the observation period.

Adult↗
PubMed1991

[Systemic lupus erythematosus. 2. Factors of predictive significance for survival].

Sixty-one of 173 patients with systemic lupus erythematosus followed for a mean of 13.9 years had severe infections which influenced their survival more than could be accounted for by the mortality (20 per cent) caused by the infections. Patients with infections had more SLE manifestations than patients without infections, and they died of lupus manifestations more often than patients without infections. Patients who went into a permanent remission and patients who died of lupus differed most markedly by the rates of infection. The rate of infection was increased more than tenfold in patients treated with high dosages of glucocorticoid compared with patients who received low dosages. Treatment with cytostatics influenced the rate of infections to a moderate degree. Nephropathy also influenced survival but half of the patients with nephropathy maintained a normal plasma creatinine in spite of the long observation period. 16 per cent of the patients with nephropathy died of kidney failure or are receiving chronic hemodialysis.

Adult↗
PubMed1991

Short- and long-range processes in structure-from-motion.

Human ability to detect 3-D structure in an array of 2-D moving dots was tested. Under limited exposure time, we found high detection rates only when the 2-D motion was restricted to the spatio-temporal region of short-range motion. Long-range moving dots failed to produce a strong impression of 3-D structure and yielded only weak detection rates. This result is consistent with the view that the processing of long-range motion is more serial than that of short-range motion.

Depth Perception↗
PubMed1991

Xeroderma pigmentosum lesions related to ultraviolet transmittance by clothes.

Xeroderma pigmentosum is associated with severe actinic degeneration of the skin. Our patient with xeroderma pigmentosum showed increasing actinic damage in some areas covered by clothes. We therefore performed a complete evaluation of the patient's exposure to ultraviolet radiation. This included transmission measurements of the patient's clothes, glasses, and car windows. The transmission of UVB (280 to 320 nm) by the clothes varied from none to 17.8%. The transmitted UVB radiation was proportional to the clinical manifestations of xeroderma pigmentosum. The patient's wardrobe was changed, and UVA-blocking film was applied to the windows of the car and house. A decline in manifestations was seen after 18 months of improved ultraviolet protection.

Adult↗
PubMed1991

Visual curve tracing properties.

Subjects decided whether 2 dots were on the same curve or 2 different curves, and the curvature of the curves or the proximity of other (distractor) curves to the target curve was varied. Response time increased as the arc length of the curve connecting the 2 dots increased, suggesting that the curve was traced to perform the task. Tracing rate was faster for low- than high-curvature contours and was increasingly slower as distractor contours were increasingly proximal to the traced curve. Proximity results were predicted by a model in which response time depends on the ratio of the distance between the dots and the distance between adjacent lines. Curve tracing operations used to integrate information along contours are sensitive to several properties of the contours. The implications of the sensitivity of tracing operations to these curve properties are discussed.

Adult↗
PubMed1990

Autoantibodies to lamins A and C in sera of patients showing peripheral fluorescent antinuclear antibody pattern on HEP-2 cells.

Lamins A, B, and C are the major proteins of a polymeric structure called nuclear lamina, which is intercalated between chromatin and the inner membrane of the nuclear envelope. Using immunofluorescence on HEp-2 cells, specific enzyme-linked immunosorbent assay, and Western blotting performed against nuclear lamina preparation from Ehrlich ascites tumor cells, we characterized three patients, whose sera contained antibodies to nuclear lamins. The reaction pattern observed in two of the patients may result from single or combined occurrence of anti-lamin A and C antibodies. The third patient had antibodies that probably recognized an epitope in the carboxy-terminal region of lamin C. The sera were donated by a heterogeneous group of patients, and no common clinical or laboratory signs seemed to link them together.

Adult↗
PubMed1990

Generalized morphea with blisters. A case report.

A patient suffering from generalized morphea developed blisters in the morpheic plaques on her buttocks. The plaques had an increased concentration of serum aminoterminal propertice of type III procollagen, an echo response and thickened skin on ultrasound scanning, and compact bundles of collagen fibrils with bimodal distribution of the diameters. The blisters appeared as an echo-free band in the subepidermal zone by ultrasound scanning. Electron microscopy revealed blisters in the upper papillary dermis, surrounded by degraded collagen fibrils.

Aged↗
PubMed1985

AIDS-induced decline of the incidence of syphilis in Denmark.

The incidence rate of acquired syphilis per 100 000 total population in Denmark increased by 70% from 6.8 in 1978 to 11.6 in 1982. In 1984 this incidence had decreased by 61.2% to 4.5. The fluctuation of the number of acquired syphilis predominated in the male population with an increase of 71.8% during the five year period 1978-1982 and a decrease of 63.2% during the years 1983 and 1984. In 1978, the incidence of acquired syphilis in males was 11.3 per 100 000 total population increasing to 19.5 in 1982, decreasing to 7.2 in 1984. The decreasing number of acquired syphilis cases during the past two years are correlated to a lower number of sexual contacts among homosexual men because of fear of AIDS.

Acquired Immunodeficiency Syndrome↗
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↗