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Biomedical subjects

G Rodriguez

Publications and source records attributed to G Rodriguez.

180 records · Page 10Linked to original sources
PubMed1975

[Relapsing childhood digital fibromatosis. Study of a case with electron and light microscopy and review of the literature].

The first Latin-American case of a relapsing digital fibromatosis in a 6 months old child is presented by the authors. With the H.E. staining cytoplasmatic inclusions were found in the fibroblasts. For the first time the presence of cellular synctitiums in the entity is described. Many of these synctitiums contain inclusion bodies. This inclusion observed with electron microscope was constituted by a considerable amount of filaments condensing in the center and the well developed stages occupying most of the cyloplasm. No viral particles were found. The accumulation of filaments in the fibroblast causes a degenerative final stage of the cells. The possibility whether this inclusion represents an accumulation of the synthetised fibers by the fibroblast or a conglomerate is not determined by this study. An extensive review of the literature on this subject is made by the authors.

Diagnosis, Differential↗
PubMedDate not supplied

The asteroid body of lobomycosis.

Lobomycosis is a dermal mycosis produced by Loboa loboi. It gives rise to dermal granulomas in which giant cells phagocytose an overwhelming number of fungi. Intracytoplasmatic asteroid bodies (AB) have been observed in some giant cells. Their nature is unknown and they have been confused with the sporotrichotic AB. We studied 84 skin biopsies from 53 patients with lobomycosis, 7 by electron microscopy (EM). Immunohistochemistry with a polyclonal anti-Sporothrix schenckii antibody was performed in five biopsies. We found AB in the giant cells in 22 of the 84 biopsies on HE staining. They appeared as single eosinophilic intracytoplasmic structures surrounded by a clear empty space. This clear space did not appear when the biopsy was fixed with OSO4, thus indicating that it is lipid in nature, and that the vacuole is an artefact produced by lipid extraction. Under the EM, the AB consist of bundles of dense, filamentous material, dense bodies and myelin structures resembling the image of AB in sarcoidosis. Some giant cells containing AB either phagocytosed only few fungi or did not contain any of them. The AB and the fungi did not react with the anti-sporotrichotic antibody, which stained the extracellular AB of sporotrichosis. These two asteroid structures are, therefore, different and unrelated phenomena.

Antibodies, Fungal↗
PubMedDate not supplied

Characteristics of intracellular calcium changes required for augmentation of phorbol ester-stimulated pancreatic enzyme secretion.

Previous studies demonstrated that Ca2+ ionophores augment the pancreatic enzyme secretion caused by phorbol esters. The present study was performed to determine the nature of the cellular Ca2+ effects responsible for the augmentation. Relatively low concentrations (0.3-1.0 microM) of the nonfluorescent Ca2+ ionophore, 4-bromo-A23187 (Br-A23187), did not measurably increase free cytosolic Ca2+ ([Ca2+]i) and caused little or no enzyme release from guinea pig pancreatic acini. However, these concentrations of Br-A23187 augmented the amylase release caused by the phorbol ester, 4 beta-phorbol 12-myristate 13-acetate (PMA). This augmentation occurred in the absence of extracellular Ca2+ as long as the intracellular agonist-sensitive pool contained Ca2+. Greater concentrations of Br-A23187 (3-10 microM) alone caused transient increases in [Ca2+]i and transient increases in amylase release. Although not resulting in an increase in [Ca2+]i, the low concentrations of Br-A23187 caused release of Ca2+ from the intracellular agonist-sensitive pool. These results suggest that Ca2+ mediates enzyme release by two distinct mechanisms in the pancreatic acinar cell. First, an increase in [Ca2+]i alone mediates enzyme release. Second, Ca2+ release from the agonist-sensitive pool not resulting in a measurable increase in [Ca2+]i augments enzyme release stimulated by a phorbol ester. The second effect of Ca2+ may be due to a small localized change in cell Ca2+ or an induction of cytosolic Ca2+ oscillations.

Amylases↗
PubMedDate not supplied

A new method to evaluate human-robot system performance.

One of the key issues in space exploration is that of deciding what space tasks are best done with humans, with robots, or a suitable combination of each. In general, human and robot skills are complementary. Humans provide as yet unmatched capabilities to perceive, think, and act when faced with anomalies and unforeseen events, but there can be huge potential risks to human safety in getting these benefits. Robots provide complementary skills in being able to work in extremely risky environments, but their ability to perceive, think, and act by themselves is currently not error-free, although these capabilities are continually improving with the emergence of new technologies. Substantial past experience validates these generally qualitative notions. However, there is a need for more rigorously systematic evaluation of human and robot roles, in order to optimize the design and performance of human-robot system architectures using well-defined performance evaluation metrics. This article summarizes a new analytical method to conduct such quantitative evaluations. While the article focuses on evaluating human-robot systems, the method is generally applicable to a much broader class of systems whose performance needs to be evaluated.

Astronauts↗
PubMedDate not supplied

Quantitative electroencephalography and regional cerebral blood flow: discriminant analysis between Alzheimer's patients and healthy controls.

Forty-two patients with probable Alzheimer's disease (AD) and 18 elderly healthy controls underwent quantitative EEG (qEEG) and regional cerebral blood flow (rCBF; 133Xe clearance) examinations. Correlations were sought between relative qEEG band powers and percent rCBF values in a posterior temporoparietal region of interest in either hemisphere. Moreover, stepwise discriminant analysis was applied to study the accuracy of the two techniques in differentiating AD from healthy ageing. rCBF and qEEG were correlated with one another, especially in the right hemisphere (p values ranging from <0.001 to <0.01). Significant correlations were found between Mini Mental State Examination (MMSE) and relative power of both the 2- to 6-Hz and the 6.5- to 12-Hz bands on either side (p < 0.001), and between MMSE and left rCBF (p < 0.005), while the correlation with right rCBF was poorer (p < 0.02). The statistical procedure identified the right values of both examinations for the discriminant analysis. Sensitivity of qEEG and rCBF employed together was 88% and specificity 89%, with a total accuracy of 88.3%. The unrecognized patients (n = 5) were affected by mild AD (4 scoring 3 at the Global Deterioration Scale and 1 scoring 4). qEEG alone showed an accuracy of 77% in the whole group and of 69% in mild AD, and rCBF alone an accuracy of 75% in the whole group and of 71% in mild AD. It is concluded that qEEG and rCBF examinations employed together are accurate tools to differentiate AD from normal ageing, although a lower degree of accuracy is achieved in mildly demented patients.

Aged↗
PubMedDate not supplied

Regional cerebral blood flow and prognostic evaluation in Alzheimer's disease.

The present investigation reports the application of regional cerebral blood flow (rCBF; (133)Xe method) to prognostic purposes in a consecutive series of 76 patients (mean age 68.4 +/- 8.7 years) with probable Alzheimer's disease (AD; NINCDS-ADRDA criteria). The likelihood that rCBF from a posterior temporal-inferior parietal area in each hemisphere at the first visit may predict timing of achievement of three endpoints (i.e. loss of activity of daily living, ADL, incontinence and death due to end-stage AD) was tested by the 'lifereg' procedure of the Statistical Analysis System package. With respect to baseline evaluation, 32 patients lost ADL 20.6 +/- 17.4 months later, 31 developed incontinence 27.1 +/- 19.0 months later, and 16 patients died after 40.9 +/- 23.8 months of follow-up. Baseline rCBF significantly predicted all end-points: the loss of ADL (left hemisphere: p = 0.04; right hemisphere: p = 0.02), incontinence (p = 0.02 in both hemispheres) and death (p = 0.01 in both hemispheres). Statistical significance was maintained for the loss of ADL and incontinence both in a subgroup of mildly demented patients, in whom death was not considered due to the low number of patients who died, and in a multivariate analysis including patient age, age at onset, sex, duration of illness, Mini-Mental State Examination score and presence of extrapyramidal signs and psychotic symptoms at the first visit. This study shows that rCBF measurement in a posterior temporal-inferior parietal area may give prognostic information on timing of evolution of AD, whenever performed during the course of the disease, and may be utilized both in clinical practice and for social planning.

Activities of Daily Living↗
PubMedDate not supplied

Regional cerebral blood flow in essential hypertension: data evaluation by a mapping system.

Regional cerebral blood flow was studied by means of the 133Xe inhalation method in 26 untreated and 10 treated patients with essential hypertension. The untreated subjects were divided into newly and previously diagnosed groups to assess the relation between regional cerebral blood flow and the duration of hypertension. The overall flow reduction was more marked in the frontal and temporal regions in the previously diagnosed group, and this was attributed to pathological changes in the district served by the middle cerebral artery. Regional temporal lobe impairment was also noted in the newly diagnosed and treated subjects. A significant correlation was found between regional cerebral blood flow and mean arterial blood pressure.

Aged↗
PubMedDate not supplied

A retrospective study of patient care needs on admission to an inpatient hospice facility.

BACKGROUND: The care and support of dying patients and their families are among the most important skills of a family physician. In this century, an increasing proportion of deaths have occurred in hospitals with resulting medicalization of the dying process. Hospice care has emerged to focus on the relief of suffering rather than the cure of illness. This descriptive study reports information about the diagnoses, care needs, and attending physicians of a cohort of patients admitted to a free-standing, inpatient hospice program. METHODS: We undertook a retrospective chart review of 335 patients admitted to a hospice program during a 26-month period, collecting data recorded on standardized nursing assessment forms. These forms provided information on 19 biologic, functional, and psychosocial symptom groups at the time of admission. RESULTS: Family physicians were the admitting physicians in a minority of hospice admissions. Pain and mobility problems were the most frequent symptoms encountered. Other common issues included bowel, respiratory, and nutritional problems. Emotional difficulties were noted less frequently than these common biomedical problems. CONCLUSIONS: Family physicians should be trained to address core problems encountered in the care of dying patients. Multidisciplinary team approaches are essential in the management of many problems encountered in hospice care.

Adult↗