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Biomedical subjects

M Goldbaum

Publications and source records attributed to M Goldbaum.

At least 19 recordsLinked to original sources
PubMed2001

The prevalence of multiple sclerosis in the city of São Paulo, Brazil, 1997.

July 1, 1997 was stipulated as the day for estimating the prevalence of multiple sclerosis within the city of São Paulo. The patients were identified via various sources, including associated universities and magnetic resonance services of the city of São Paulo. The area covered by the study has a population of 9,380,000, mainly white and of European origin, with a large number of immigrants from Spain and Portugal. The patients were classified in accordance with the criteria of Poser et al. (1983), and only those with defined multiple sclerosis were registered. The study gave a prevalence of 15.0/10(5) inhabitants, or three times the value obtained in a similar study in 1990. This increase reveals the larger number of cases encompassed by the study, and is attributed to the use of more detailed recording methods, improvements in diagnosis, and better conditions for treatment.

Adult↗
PubMed2000

Polypoidal choroidal vasculopathy masquerading as central serous chorioretinopathy.

OBJECTIVE: To differentiate polypoidal choroidal vasculopathy (PCV) from central serous chorioretinopathy (CSC). DESIGN: A retrospective, observational case series. PARTICIPANTS: Thirteen patients originally diagnosed with CSC proved to have PCV after more extensive evaluation and follow-up. METHODS: A clinical and angiographic review of patients with manifestations of CSC, including macular detachment. MAIN OUTCOME MEASURES: Demographic data, funduscopic examination, and fluorescein and indocyanine green (ICG) angiographic findings. RESULTS: Thirteen patients initially suspected of having CSC were ultimately diagnosed as having PCV. These eyes had exudative macular detachments secondary to a small caliber, polypoidal choroidal vascular abnormality or so-called polypoidal choroidal neovascularization. The clinical manifestations in the fundus varied. They included multiple, variably sized serous pigment epithelial detachments, neurosensory retinal detachment, lipid deposition, patchy atrophy of the pigment epithelium and indistinct staining from decompensation of the posterior blood-retinal barrier on fluorescein angiography. In reality, the suspected PEDs proved to be polypoidal lesions of PCV when imaged with ICG angiography. CONCLUSIONS: The clinical diagnosis of CSC or PCV generally poses little challenge to the experienced retinal specialist. However, in CSC with persistent and/or recurrent exudation, a myriad of retinal pigment epithelial changes may evolve that make it difficult to differentiate these two entities. In such patients, ICG angiography is useful in differentiating CSC from PCV. An accurate clinical diagnosis is important since each of these entities, CSC and PCV, may differ in terms of their risk factors, natural course, and visual prognosis.

Adult↗
PubMed2000

Locating blood vessels in retinal images by piecewise threshold probing of a matched filter response.

We describe an automated method to locate and outline blood vessels in images of the ocular fundus. Such a tool should prove useful to eye care specialists for purposes of patient screening, treatment evaluation, and clinical study. Our method differs from previously known methods in that it uses local and global vessel features cooperatively to segment the vessel network. We evaluate our method using hand-labeled ground truth segmentations of 20 images. A plot of the operating characteristic shows that our method reduces false positives by as much as 15 times over basic thresholding of a matched filter response (MFR), at up to a 75% true positive rate. For a baseline, we also compared the ground truth against a second hand-labeling, yielding a 90% true positive and a 4% false positive detection rate, on average. These numbers suggest there is still room for a 15% true positive rate improvement, with the same false positive rate, over our method. We are making all our images and hand labelings publicly available for interested researchers to use in evaluating related methods.

Algorithms↗
PubMed1999

Polypoidal choroidal vasculopathy and neovascularized age-related macular degeneration.

OBJECTIVE: To determine the nature and frequency of polypoidal choroidal vasculopathy (PCV) in a series of patients suspected of having neovascularized age-related macular degeneration (AMD). METHODS: A prospective analysis of 167 consecutive, newly diagnosed patients aged 55 years or older with presumed neovascularized AMD was performed. All patients were examined with fundus biomicroscopy as well as fluorescein and indocyanine green angiography. RESULTS: Choroidal neovascularization secondary to AMD was diagnosed in 154 (92.2%) of 167 patients; 13 (7.8%) patients had PCV. The patients affected by PCV were younger than those with AMD (P = .01). Peripapillary choroidal neovascularization was seen in 3 (1.9%) of 154 patients with AMD and 3 (23.1%) of 13 patients with PCV (P = .006). Significant drusen were present in 63 (70%) of 90 fellow eyes with unilateral AMD compared with only 1 (16.7%) of 6 eyes with PCV (P = .02). Only 5 patients with AMD (3.2%) were nonwhite compared with 3 patients with PCV (23.1%) (P = .02). CONCLUSIONS: A measurable number of elderly patients with findings suggestive of neovascularized AMD and serosanguineous macular manifestations will instead have PCV. Polypoidal choroidal vasculopathy can occur in any sex or race, but is more commonly seen in the peripapillary area, without associated drusen, and in nonwhite patients. It is important to differentiate AMD from PCV because there are significant differences in the demographic risk profile, natural course, visual prognosis, and management of these patients.

Aged↗
PubMed1998

Locating blood vessels in retinal images by piece-wise threshold probing of a matched filter response.

We describe an automated method to locate and outline blood vessels in images of the ocular fundus. Such a tool should prove useful to eyecare specialists for purposes of patient screening, treatment evaluation, and clinical study. Our method differs from previously known methods in that it uses local and global vessel features cooperatively to segment the vessel network. A comparison of our method against hand-labeled ground truth segmentations of five images yielded 65% sensitivity and 81% specificity. A previously known technique yielded 69% sensitivity and 63% specificity. For a baseline, we also compared the ground truth against a second hand labeling, yielding 80% sensitivity and 90% specificity. These numbers indicate our method improves upon the previously known technique, but that further improvement is still possible.

Algorithms↗
PubMed1997

[Production of scientific articles about health in six Latin American countries, 1973-1992].

The production of articles resulting from biomedical, clinical, and public health studies that originated in Argentina, Brazil, Chile, Cuba, Mexico, and Venezuela from 1973 through 1992 was analyzed to discover trends in health research in Latin America. From the database of the Institute for Scientific Information (ISI), 41,238 articles with first authors who resided in those countries were extracted. These articles were analyzed by subject area, type of study, country, number of authors and institutions that participated in the investigation, and citations received by each article. Also analyzed were 95 articles in epidemiology selected from a pool of 570 published by authors from the six countries in 11 public health journals that enjoy international prestige. The results showed that the number of published works increased by 117% between the first and last five-year periods within the study period. Clinical research was distributed the most evenly among the countries, and public health research was the most concentrated (60.7% originated in Brazil). The numbers of biomedical and public health research articles showed relatively more growth than those reporting on clinical research throughout the period. A relative decrease was found in articles by only one author, which suggests a greater frequency of team efforts, and an increase was seen in articles with authors tied to two or more national or foreign institutions, which indicates greater cooperation between institutions and countries. The average number of citations received by each article was 3, which was less than half the number received by the articles in the ISI database (7.78). Regarding the subset of 95 articles in epidemiology, the great majority (96%) dealt with infectious diseases or maternal and child health, while in the international literature 78% of such articles were about chronic diseases. This group of articles gave evidence of more cooperation with international institutions and had a citation index of 4.36 per article. It is concluded that, despite the inherent limitations, this type of study reveals some general trends in the development of research in the six Latin American countries with the greatest scientific production and makes it possible to formulate hypotheses on the factors that influence these trends. Taken with the paper caution, the results of studies like this one can be of great value in defining health science and technology policies.

Argentina↗
PubMed1997

Automated measurement of retinal vascular tortuosity.

Automatic measurement of blood vessel tortuosity is a useful capability for automatic ophthalmological diagnostic tools. We describe a suite of automated tortuosity measures for blood vessel segments extracted from RGB retinal images. The tortuosity measures were evaluated in two classification tasks: (1) classifying the tortuosity of blood vessel segments and (2) classifying the tortuosity of blood vessel networks. These tortuosity measures were able to achieve a classification rate of 91% for the first problem and 95% on the second problem, which confirms that they capture much of the ophthalmologists' notion of tortuosity.

Fundus Oculi↗
PubMed1996

[Epidemiology and health services]

The growing application of epidemiological investigation to the health and medical field has consolidated its various uses in health care services. Brazilian legislation now provides back-up for four different types of applications, although their implementation is still precarious: analysis of the health situation, epidemiological surveillance, etiological studies, and evaluation of health care services, programs, and technologies. Proper deployment of such epidemiological applications on both the political/institutional and operational levels will provide relevant subsidies for health services in conducting their activities.

Journal Article↗
PubMed1993

[Streptokinase in severe pulmonary thromboembolism].

Severe pulmonary embolism (PE) was treated with streptokinase in four patients, three men and one woman, age 38 to 72 (mean = 53 +/- 14) years. Before the thrombolytic therapy, all patients had pulmonary angiogram and hemodynamic parameters analyzed. The drug was infused through the distal lumen of the Swan-Ganz catheter at the pulmonary artery trunk. The initial dosage was 250,000 units "in bolus" and 100,000 units in 24 to 72 hours. The time interval between the symptoms and treatment had ranged from 2 hours to 5 days. The results are analyzed as follow: reduction on right atrial pressure, mean pulmonary pressure, pulmonary vascular resistance, an increase in the stroke volume and cardiac output. In two cases we observed total lysis, in one partial lysis and one patient died from severe form of PE and late infusion of SK. Reinfusion of the drug was necessary in one patient that had PE recurrence with reliable final result. Finally, no one had severe bleeding despite the use of the intrapulmonary catheter.

Adult↗
PubMed1982

The immune response to homologous lens crystallin. I. Antibody production after lens injury.

Using a sensitive radioimmunoassay to homologous mouse alpha-crystallin, it was established that autoantibodies are produced to this self constituent in mice after rupture of the lens capsule by needling. Antibody to lens crystallin was detected within 4 days of lens rupture and persisted for 24 days, suggesting that these mice are not tolerant to alpha-crystallin at the B cell level. However, T cells from mice immunized with homologous crystallin cannot be stimulated to proliferate by either homologous or heterologous crystallin. On the other hand, lymphocytes from mice immunized with bovine alpha-crystallin can be stimulated to proliferate to bovine crystallin, but not to either unfractionated mouse crystallin (MC) or purified mouse alpha-crystallin. At the level of detection, therefore, T cells appear to be tolerant to homologous alpha-crystallin, but not to heterologous alpha-crystallin. LPS resulting from bacterial contamination after needling was ruled out as a necessity for antibody production because antibody to mouse alpha-crystallin was produced after sterile lens rupture with a laser. However, LPS and poly A:U did enhance the antibody response to alpha-crystallin. These data suggest that T cells, but not B cells, are tolerant to homologous crystallin and that antibody results from circumvention of specific helper T cell requirements for antibody synthesis. The implications of these findings for tolerance and autoimmune uveitis are discussed.

Animals↗