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Biomedical subjects

S Ullman

Publications and source records attributed to S Ullman.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1989

Aligning pictorial descriptions: an approach to object recognition.

This paper examines the problem of shape-based object recognition, and proposes a new approach, the alignment of pictorial descriptions. The first part of the paper reviews general approaches to visual object recognition, and divides these approaches into three broad classes: invariant properties methods, object decomposition methods, and alignment methods. The second part presents the alignment method. In this approach the recognition process is divided into two stages. The first determines the transformation in space that is necessary to bring the viewed object into alignment with possible object models. This stage can proceed on the basis of minimal information, such as the object's dominant orientation, or a small number of corresponding feature points in the object and model. The second stage determines the model that best matches the viewed object. At this stage, the search is over all the possible object models, but not over their possible views, since the transformation has already been determined uniquely in the alignment stage. The proposed alignment method also uses abstract description, but unlike structural description methods it uses them pictorially, rather than in symbolic structural descriptions.

Form Perception↗
PubMed1989

The development of AIDS or AIDS-related conditions in a cohort of HIV antibody-positive homosexual men during a 3-year follow-up period.

One hundred and thirty-three homosexual men seropositive for the antibody against human immunodeficiency virus (HIV) were enrolled in a prospective study in 1984-85. The 3-year cumulative incidences of the acquired immunodeficiency syndrome (AIDS) and AIDS-related conditions, by life-table analyses, were 18% and 34%. The cumulative incidence of immune deficiency defined as CD4 lymphocytes less than 0.5 x 10(9) l-1 was 70% at 3 years. Absence of antibodies to p24 antigen, HIV antigenaemia, CD4 lymphocytes less than 0.3 x 10 l-1 and elevated serum level of IgA were significantly associated with the development of AIDS. There was no association between disease progression and persistent generalized lymphadenopathy. When adjusted to the probable year of infection, these results are in accordance with previous cohort studies. It is concluded that most, or all, subjects seropositive for HIV will develop progressive loss of CD4 lymphocytes followed by clinical signs of immune deficiency, and that differences among previous cohorts with respect to disease progression are probably due to differences in the duration of infection.

AIDS-Related Complex↗
PubMed1988

Necrotizing keratitis caused by Capnocytophaga ochracea.

We studied three cases of Capnocytophaga keratitis that demonstrated stromal necrosis and a ring infiltrate. In all cases, the keratitis occurred in a previously diseased or traumatized cornea. One patient was treated with chronic antiamoebic therapy for presumed Acanthamoeba keratitis. Two cases resulted in corneal perforation. Laboratory isolation was difficult because of slow, fastidious growth. Capnocytophaga is not uniformly sensitive to commonly used topical antibiotics such as the cephalosporins and aminoglycosides, but may respond to treatment with topical clindamycin.

Adult↗
PubMed1988

Living with Asthma. I. Genesis and development of a self-management program for childhood asthma.

This paper traces the roots of Living with Asthma, a self-management program for childhood asthma, from the Children's Asthma Research Institute and Hospital (CARIH), a residential treatment center in Denver, Colorado. The basic components of the program were developed and tested over the 40-year history of CARIH; the findings of an educational unit were added to this accumulated knowledge and expertise to complete the system. The program rests heavily on social learning theory, particularly two major tenets: 1) the concept of reciprocal determinism and 2) the learning/performance dichotomy. The crucial role of these concepts is described here, especially with respect to the design of the program and the selection of dependent variables. The remainder of this article describes the essentials of Living with Asthma, particularly the skills taught and performed by patients in a formal evaluation of the system. The design of the study, characteristics of patients enrolled in the program, and results obtained with the system are discussed. The program proved highly effective in significantly improving the knowledge of asthma in parents and their children, and in developing positive attitudes in both groups. It also produced significant reductions in the number of attacks experienced by the youngsters and improved their peak flow values. Participation in the program resulted in changes in morbidity indices of asthma, including significant reductions in school absenteeism and health-care costs incurred because of the disorder. These changes, it was concluded, reflected the result of the performance by patients of the self-management skills taught in Living with Asthma, coupled with the exceptional medical treatment they received.

Absenteeism↗
PubMed1987

Lymphocyte transformation response to pokeweed mitogen as a predictive marker for development of AIDS and AIDS related symptoms in homosexual men with HIV antibodies.

To identify factors that may predict the development of the acquired immune deficiency syndrome (AIDS) or AIDS related symptoms various immunological measurements were studied in a group of homosexual men attending screening clinics for AIDS in Copenhagen. Fifty seven men whose ratio of T helper lymphocytes to T suppressor lymphocytes (CD4:CD8 ratio) was less than 1.0 before the study began were included. Forty two were positive for antibody to the human immunodeficiency virus (HIV), of whom 38 were reinvestigated after a median observation period of 10 months. Among the seropositive men the transformation responses to pokeweed mitogen and cytomegalovirus and the absolute count of CD4 positive lymphocytes were the most common abnormal values. In particular, a low relative response to pokeweed mitogen on initial investigation correlated with a worsened clinical condition on reinvestigation. The risk of a worsened clinical condition was 55 times higher in seropositive men whose responses to pokeweed mitogen were low than in other seropositive men. The corresponding relative risks for low transformation responses to cytomegalovirus and for a decreased absolute count of CD4 positive lymphocytes were 18 and six. The relative response to pokeweed mitogen is therefore a very sensitive short term predictive marker of the clinical condition of seropositive patients who have a CD4:CD8 ratio of less than 1.0.

AIDS-Related Complex↗
PubMed1987

Parallel and serial processes in motion detection.

Apparent motion was used to explore humans' ability to perceive the direction of motion in the visual field. A marked qualitative difference in this ability was found between short- and long-range motion. For short-range motion, the detection of the direction of motion is characterized by parallel operation over a wide visual field (that is, detection performance is independent of the number of objects in an array). When the positional displacement is large relative to an object's size, the direction of motion is detected in a serial manner. The process of detection is limited in this case by the ability to detect other events, such as appearance and disappearance of an object, and the ability to compute their spatio-temporal relations. The results are consistent with a previously suggested division of the motion detection system into short- and long-range processes. The direction of short-range motion can be perceived in parallel (preattentively), whereas long-range motion is attentive and requires more complicated computations. It seems that the detection of long-range motion is a conjunction task, combining the detection of disappearance and appearance.

Humans↗