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Biomedical subjects

F Espinosa

Publications and source records attributed to F Espinosa.

26 records · Page 2Linked to original sources
PubMed1984

A randomized placebo-controlled double-blind trial of nimodipine after SAH in monkeys. Part 1: Clinical and radiological findings.

The authors have developed a method to induce chronic cerebral vasospasm after subarachnoid hemorrhage (SAH) in monkeys. With microsurgical techniques, 33 monkeys had a frontotemporal craniectomy and unilateral opening of the subarachnoid cisterns. Cerebrospinal fluid was drained and a fresh hematoma, obtained from an average of 7 ml of autologous blood, was carefully placed against the major arteries of the anterior circulation on one side. The 30 monkeys studied for 7 to 14 days after the SAH were allocated randomly to two treatment groups of 15: one group received placebo and the other nimodipine, 1 mg/kg every 8 hours. Indices monitored before and after SAH included neurological status, cerebral blood flow, computerized tomography, and angiographic vessel caliber. In the placebo group, delayed ischemic neurological deficit developed in one monkey 4 days after clot placement and was present at sacrifice on Day 14. No such deficit occurred in the nimodipine group. The effect of nimodipine on vessel caliber at this dosage was equivocal. Significant vasospasm (31% to 100% reduction in vessel caliber) developed in 87% (26 of 30) of the animals. Overall, vasospasm was slightly more common in the placebo group: in this group, on Days 7 and 14, the incidence of vasospasm was significantly higher (p less than 0.05) than in the nimodipine group. However, the average percentage reduction in vessel caliber of the maximally constricted vessel in each monkey was not significantly different between the two groups.

Animals↗
PubMed1984

A randomized placebo-controlled double-blind trial of nimodipine after SAH in monkeys. Part 2: Pathological findings.

Chronic cerebral vasospasm was induced in monkeys by placement of an autologous blood clot after the basal cisterns had been opened over the arteries of the circle of Willis on one side. The experimental protocol was detailed in Part 1 of this paper. Twenty of the 30 monkeys studied from both groups (one receiving placebo and the other nimodipine) underwent cerebral fixation (Day 14) at controlled pressure by intra-arterial perfusion. The arteries at the base of the brain were studied by light microscopy and scanning (SEM) and transmission electron microscopy (TEM). Cerebral angiography on Day 7 showed that vasospasm was significantly more common (p less than 0.0001) and more severe (p less than 0.01) on the clot side compared to the control or non-clot side. Vasospasm was less severe on Day 14, just before sacrifice. On SEM, 80% of the 20 middle cerebral artery (MCA) specimens that had been in spasm (Day 7) showed marked corrugation , and in some the endothelium had a fish-scale appearance. All of the 10 MCA's on the clot side examined by TEM that had been in spasm (Day 7) showed marked changes such as endothelial swelling, subendothelial proliferation, corrugation of the elastic lamina, and myonecrosis. With few exceptions, none of the basilar arteries or MCA's on the non-clot (control) side showed any abnormalities. The pathological findings of vessels in spasm were considered to be slightly less severe in the nimodipine group; however, the trial drug (1 mg/kg/8 hrs) did not prevent such abnormalities from occurring. The ultrastructural changes in the arterial walls of specimens from both placebo and nimodipine groups in vasospasm are described. Since dramatic changes are present in the vessel walls even after radiologically visible vasospasm has almost completely abated, we believe that vasospasm is due to long-lasting smooth-muscle constriction and not to vessel wall thickening caused by a cellular or subcellular infiltrate.

Animals↗
PubMed1982

Chronic cerebral vasospasm after large subarachnoid hemorrhage in monkeys.

The authors have developed a model of chronic cerebral vasospasm analogous to the clinical situation, by inducing a large subarachnoid hemorrhage (SAH) in monkeys. With this model, the size of the SAH apparent on the first computerized tomography (CT) scan was correlated with the incidence and severity of cerebral vasospasm that developed. Indices monitored for up to 21 days after SAH included cranial CT scan, cerebral blood flow, vessel caliber, and neurological status. The 18 monkeys studied for 48 hours or more were divided into two groups according to the size of the SAH on CT scan. Vasospasm was more common in the group with large SAH. In this group, on Days 0, 7, and 14, the incidence of vasospasm was significantly higher than at other times (p less than 0.001, p less than 0.01, and p less than 0.05, respectively), and the percentage reduction in vessel caliber was significantly greater than in the group with small/medium SAH (Day 7, p less than 0.02; Days 0 and 14, p less than 0.05). Delayed neurological deficit developed in two monkeys with large SHA. Apathy was noted from Day 17 to Day 21 in one, and unsteadiness and drowsiness were noted on Days 4 and 5 in the other. Overall, the incidence, degree, and time course of vasospasm reflected the size of the hemorrhage.

Animals↗
PubMed1980

New contribution on the oesophageal mucous innervation in certain monkeys (Cercopithecidae).

Spindle-shaped, barrel-like, or bush-like corpuscular neural structures situated in the mucous epithelium of the upper third of the oesophagus are described. These structures are not homogeneously distributed in this area. Some are very close to the pharyngooesophageal sphincter, spanning the thickness of the epithelium and communicating with the basal membrane by means of a thin pedicle and with the lumen by a small hilus or pore, their morphology being that of a taste bud. The others are situated deeper in the mucous epithelium of the upper third, communicating with the basal membrane only by means of either a thin pedicle or a thicker one, and separated from the lumen by a thick layer of epithelial cells. The bush-like apparatuses lie closely adjacent to the basal membrane of the epithelium.

Animals↗
PubMed1979

Spinous leafy nerve endings in the feline stomach wall.

The Champy-Maillet ZIO technique has been applied to the study of the muscular tunic of the stomach. In the corpus and antrum pyloricum some nerve fibres end in non-capsulated expansions owning thorn-like protrusions. Their morphology is studied and a possibly functional sensory significance is proposed, on the basis of previous experimental results.

Animals↗
PubMedDate not supplied

Quantitative assessment of cerebral hemodynamics using CT: stability, accuracy, and precision studies in dogs.

PURPOSE: The limited clinical availability of currently used methods to measure regional cerebral blood volume (CBV) and cerebral blood flow (CBF) represents an important restriction. We undertook this study to evaluate a new dynamic CT method to measure CBV and CBF in normal and ischemic tissue. METHOD: A total of 21 dynamic CT studies were performed in seven male beagles. The contrast enhancement curves of the carotid arteries and of various brain regions were deconvolved to obtain CBV and CBF. The stability of the deconvolution method employed was assessed by comparing three data sets obtained by analyses of one, two, and four regions of interest (ROIs), all covering the entire brain area. The accuracy of CT-derived CBF was analyzed for normal (n = 5 studies) and ischemic (n = 7 studies) brain tissue using fluorescent microspheres. Repetitive CT studies were performed to evaluate the precision of the CT measurements. RESULTS: The stability of the deconvolution method was high with variabilities of 2.3% (CBV), 5.9% (CBF), and 8.9% (mean transit time), respectively. The correlation between the CT and the microsphere measurements was good for both normal and ischemia studies (r > 0.78, slope > 0.9). The variability of the CT CBF (30.6%) was higher than that of the CT CBV (12.3%) measurements. CONCLUSION: Our novel dynamic CT method is stable with respect to the sizes of ROIs used, allowing for accurate measurements of CBV and CBF in both normal and ischemic tissue. Further studies are necessary to evaluate the variability of this method under controlled physiologic conditions.

Animals↗
PubMedDate not supplied

[Leukocyte migration inhibitory factor and basophil degranulation in drug reactions].

We performed a prospective study in patients with a medical history of adverse reaction to drugs with the purpose of rule out allergy. We included 31 patients who were attended in the Allergy Service. We compared the sensibility and specificity of the test of inhibition factor of leucocytes migration and degranulation basophil against the exposition. After the statistical analysis, we concluded: the laboratory test, we have already mentioned, have little sensibility and specificity so the exposition test in the quickest, useful, and more simple method to determine drugs allergy, but more dangerous.

Adolescent↗