Biomedical subjects

J Acosta

Publications and source records attributed to J Acosta.

At least 37 records · Page 2Linked to original sources

PubMed1996

Congenital desmoid tumor of the scalp: a histologically benign lesion with aggressive clinical behavior.

Desmoid tumors are uncommon benign neoplasms of fibroblastic origin, frequently presenting in the abdomen or abdominal wall of adults. This tumor is well known to general surgeons and pathologists, but it has rarely been reported in the neurosurgical literature. We describe a neonate who presented with a right temporal subscalp tumor at birth. In spite of initial apparent total removal, the tumor recurred twice. We discuss the diagnostic pitfalls encountered in assessing this tumor and the difficulties in distinguishing, in the excised specimens, between desmoid and reactive fibrosis. We suggest that desmoid tumor should be considered in the differential diagnosis of scalp and calvarial masses in children. Complete excision is required to prevent recurrences, and sometimes a multidisciplinary team is needed to secure margin-free resection.

Adult↗

PubMed1995

Ulcerated atherosclerotic plaques in the thoracic aorta are associated with cryptogenic stroke: a multiplane transesophageal echocardiographic study.

Atherosclerotic plaque ulcers > or = 2 mm in depth and width in the thoracic aorta have been implicated by autopsy study as a cause of unexplained or cryptogenic ischemic strokes. Transesophageal echocardiography (TEE) allows visualization of complex atherosclerotic lesions of the thoracic aorta. We compared the prevalence of thoracic aorta ulcerated plaques (ulcers > or = 2 mm in both depth and width) in three age-matched groups undergoing multiplane TEE: group 1, 23 patients with cryptogenic ischemic stroke; group 2, 26 patients with known-cause strokes; and group 3, 57 control patients without strokes. TEEs were interpreted in a blinded fashion. Ulcerated plaques were found in 9 (39%) group 1 patients but in only 2 (8%) group 2 patients and in only 4 (7%) group 3 patients (p < 0.001). There was an association between advancing age and the presence of ulcerated plaques (p < 0.02). We conclude that ulcerated atherosclerotic plaques in the thoracic aorta are associated with cryptogenic ischemic stroke and should be considered a potential source of cerebral emboli.

Aged↗

PubMed1991

Effects of noradrenaline and insulin on electrical activity in white adipose tissue of rat.

An active change in membrane voltage responses to hyperpolarizing pulses has been identified by intracellular recording on an in vitro preparation of white adipose tissue. This change was characterized by a slow return to baseline at the offset of the pulses. Amplitude and duration of the slow return to baseline were dependent on extracellular K+ concentration, and were diminished by external application of Ba2+. Such properties suggest that this electrical response can be mainly due to activation of transient K+ conductances. The effects that noradrenaline and insulin have over the slow return to baseline have been also studied. While external addition of noradrenaline decreased amplitude and duration of this electrical response, insulin produced the opposite effect. These results suggest that noradrenaline and insulin could modulate K+ conductances in white adipocytes.

Adipose Tissue↗

PubMed1990

Electrical activity in white adipose tissue of rat.

Intracellular recording of white adipocytes was performed in an in vitro preparation. Resting potential, input resistance and membrane time constant averaged: -34 +/- 9 mV, 295 +/- 161 M omega, and 58 +/- 19 ms respectively (mean +/- SD, n = 32). Intracellular injection of positive and negative square current pulses elicited membrane voltage responses, characterized by a rectification of the voltage change evoked by positive pulses, and a slow return to baseline at the offset of hyperpolarizing pulses. The amplitude and duration of the slow return to resting potential was dependent on membrane potential, pulse duration, and extracellular K+ concentration. This response was depressed when external Ca2+ was replaced by Co2+, and by external application of 4-aminopyridine. These results indicate that white adipocytes can generate membrane voltage responses which may mostly be a consequence of the activity of ionic channels. The properties of the slow return to baseline suggest that it may be due to a transient K+ current.

4-Aminopyridine↗

PubMed1988

Reevaluation of corneal complications after closed vitrectomy.

Corneal complications after closed vitrectomy were analyzed in patients treated by the same surgeon from January 1980 through December 1986. Of 428 eyes (400 patients), 64 (15%) had corneal complications, 58 (13.6%) had epithelial defects, and 12 (2.8%) had corneal edema. Among 206 diabetic eyes, 41 (19.9%) had corneal complications. Of 222 nondiabetic eyes, only 23 (10.4%) showed complications. Multiple regression analysis of possible contributing factors was performed. Diabetes, intraoperative lensectomy, and history of vitreous surgery were related significantly to the occurrence of all corneal complications combined. Our series showed a significantly decreased complication rate when compared with a previous study. Improved preoperative surgical preparation and intraoperative technique to minimize corneal trauma may have accounted for the decrease.

Cornea↗

PubMed1988

Use of circularly polarized light in fundus and optic disc photography.

Circularly polarized light was used in fundus and optic disc photography to reduce reflected glare and photographic artifacts originating from the ocular media and the lenses of the fundus camera. A standard fundus camera was used, with circular polarizers placed in the illumination and observation paths. The quality of fundus photography was improved significantly in eyes with intraocular lenses, cataract, vitreous haze, or high myopia as well as in normal eyes, in fundus photography of the retinal periphery, and in optic disc photography.

Fundus Oculi↗

PubMed1987

Use of high-density fluorosilicone oil in open-sky vitrectomy.

During prolonged open-sky vitrectomy, fluid accumulates in the suprachoroidal and subretinal spaces and the resultant ballooning of the choroid and of the retina interferes with the surgery. Fluorosilicone oil (polymethyl-3,3,3-trifluoropropylsiloxane) with a specific gravity of 1.28 was tested for use as a temporary vitreous substitute during open-sky vitrectomy. After open-sky vitrectomy and bullous retinal detachment in pigmented rabbits, fluorosilicone oil flattened the retina completely in nine of nine eyes, whereas 1% sodium hyaluronate solution flattened the retina completely in only four of nine eyes. The flattening effect of fluorosilicone oil on the retina was also better than that of 1% sodium hyaluronate in an experiment with retinal detachment and giant retinal tear after open-sky vitrectomy.

Animals↗

PubMed1987

[Preparation and evaluation of fish portions from shrimp by-catch].

Fish portions were obtained from a mixture of fish flesh from shrimp by-catch. Physical, chemical, microbiological and sensory tests were done to evaluate quality of raw materials, formulations and processing conditions. Several technological procedures proved to be feasible for this product. Stability of frozen products for four months was determined by physical, chemical and microbiological tests, the results of which indicated its stability during the study period. Findings of our study, therefore, suggest the potential of shrimp by-catch for the preparation of fish portions in view of its high acceptability and simple processing technique, by using marine resources not fully utilized at present.

Animals↗

PubMed1984