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Biomedical subjects

A Cordoba

Publications and source records attributed to A Cordoba.

13 recordsLinked to original sources
PubMed1999

Corrosive effects from the deposition of gaseous pollutants on surfaces of cultural and artistic value inside museums.

The objectives of the project were to assess the critical relationships between environmental factors and damage of the artifacts and other cultural property exposed inside museums, by studying: (a) the outdoor/indoor pollutant concentration and their transfer inside the museum; (b) the distribution and circulation of pollutants inside the museum influenced by various factors; (c) chemical interactions between pollutants in the gas phase leading to removal and/or formation of secondary pollutants; (d) the final deposition of the indoor pollutants on surfaces of artistic interest and the damage on them, governed by strictly defined physicochemical parameters. All the above information, together with the main factors influencing each stage, were obtained by applying the methodology developed and described in detail here. Measurements of rate constants of reactions in the gas phase, of physicochemical deposition parameters on artefacts, and the synergistic effects of pollutants on the deposition parameters, were conducted. Seven PC programmes for analysing the experimental data were written and used. The pollutants, the solid materials and the museums chosen in this programme are only examples needed to develop the necessary methodology. The numerical results obtained serve the purpose of exemplifying the procedures and not enriching the world's bibliography with useless empirical information. Two commercially available protectives for marble were investigated from the point of view of their reactivity towards SO2 by using a diffusional technique. From measurements of SO2 concentration carried out on three types of marble, the deposition velocities have been calculated. Indoor monitoring of the church of San Luigi dei Francesi and of the Museo della Civiltá Romana in Rome has shown that indoor production of nitrous acid most likely results from heterogeneous reactions indoors, on the walls and the exposed surfaces.

Adsorption↗
PubMed1998

[Optic neuromyelitis and bilateral acute retinal necrosis due to varicella zoster in a patient with AIDS].

We report a case of bilateral acute retinal necrosis (ARN) following an acute optic neuromyelitis (AONM) in an immunodepressed patient (T CD4 lymphocyte count under 50/mm3) suffering from acquired immunodeficiency syndrome (AIDS). Despite the medical treatment the evolution led to blindness by bilateral total retinal detachment. The neuro-ophthalmological features occurred prior to the retinal manifestation, and the acute optic neuromyelitis occurred after a spreading zoster. The varicella-zoster virus (VZV) seemed to be involved because of recurring cutaneous zoster, spreading of this zoster just before the AONM, previous reports showing a link between VZV and AONM, and VZV and ARN. However, our patient had first an AONM responding well to corticosteroid therapy following one month later by an ARN leading to blindness despite the antiviral treatments received as soon as possible. There is a chronical viremia+ in immunodepressed patients with recurring and spreading zoster. The rupture of the hemato-encephalic barrier observed in AONM could facilitate the invasion of the eye by the virus, leading to an ARN. This hypothesis could explain the two complications due to the VZV, the AONM and the ARN, the first one is of dysimmunitary origin and the second one could probably result of a direct viral attack of the retina. This should incite to treat as soon as possible each retrobulbar optic neuritis in patients with AIDS, especially if past history of zoster.

AIDS-Related Opportunistic Infections↗
PubMed1986

Delayed life-threatening hemothorax associated with rib fractures.

We present two cases of delayed, massive, life-threatening hemothorax due to intercostal hemorrhage in association with fractured ribs and severe blunt chest trauma (SBCT), a combination we have not seen described in the literature. Blunt chest trauma is not benign. Significant intrathoracic injuries are frequent although usually not life threatening. However, associated extrathoracic injuries are also common and much more lethal. Most cases of hemo- and pneumothorax associated with SBCT can be treated without thoracotomy. However, rapid blood loss requires immediate open thoracotomy and surgical attention. Several days of observation in hospital may be required for patients with SBCT and fractured ribs even without any other obvious intra- or extra-thoracic injuries. Vigorous activity or chest physical therapy may be dangerous during the first several days after the injury.

Accidents, Occupational↗
PubMed1977

On differentiation of integrals.

A technique is introduced to relate differentiation and covering properties of a basis. In particular, we find that the basis associated with a sparse set of directions differentiates integrals of functions locally in L(2).

Journal Article↗
PubMed1977

Scintiscanning in venous thrombosis of the lower extremities.

Venous scintiscanning was performed once or serially in 252 patients in whom deep vein thrombosis of the lower extremities was suspected, representing a total of 494 limbs examined and 1,266 venous scintiscans performed. When controlled with roentgenologic contrast phlebography, the diagnostic accuracy rate of the isotopic method was 94.4 per cent, which increased up to 98.5 per cent when the thrombotic process was located in a major vein of the upper thigh or pelvis. There were 5.6 per cent false-positive and no false-negative diagnoses. The parameters that we have considered to be the most significant for the accurate interpretation of venous scintiscanning of the lower extremities are mentioned. Venous scintiscanning is a safe, simple and highly reliable method for the study of deep venous thrombotic disease of the lower extremitites.

Collateral Circulation↗
PubMed1975

Comatose state maintained during eight years following a vascular ponto-mesencephalic lesion.

A 24-year-old man survived for 8 years after a vascular lesion of the pons and midbrain. During these years a subresponsive comatose state with neurological signs extending from the oculomotor nuclei to the trigeminal and facial nuclei levels was present. A decorticated type of rigidity, with bilateral paralysis of the limbs accompanied by pyramidal signs, was also present. The EEG during the first months showed slow activity which afterwards gradually changed towards fast and alpha activities, maintained in the course of the years. The pathological diagnosis was a fibrous endarteritis, mainly in the territory of the basilar and vertebral arteries. The pons and midbrain, presenting a large cystic infarct, were serially studied to determine the anatomical extent of the lesion. After reviewing other examples from the literature, the clinical features of our case are discussed. The evolution of the EEG is related to different structures of the ponto-mesencephalic region with different functional activities.

Adult↗
PubMedDate not supplied

An artificial sphincter: a preliminary report.

A new method of providing continence to patients with fecal stomas is presented. The device, used as an artificial sphincter, consists of an inflatable Silastic balloon, which is implanted in the subcutaneous tissue around the stoma; it is easily handled by the patient. The artificial sphincter was used in six patients with colostomies. In all cases, satisfactory continence of the stoma was achieved, obviating the need to use enemas, bags or other appliances. In three patients subcutaneous infections developed around the prosthesis. In two cases, this was readily controlled; in one case, the prosthesis had to be removed. The other five patients are well and continent. None of the patients experienced pain or discomfort during use of the prosthesis. There has been no stomal ischemia.

Anal Canal↗
PubMedDate not supplied

[Relationship between discontinuous sucrose gradient and viability of Cryptosporidium sp. oocysts].

Cryptosporidium sp. causes self-limiting gastroenteritis in immunocompetent individuals and can produce a life-threatening chronic diarrhea in immunodeficient patients. In order to obtain populations of selectively infective oocysts for inoculation in biological experiments, we developed an operational protocol for the enrichment of viable oocysts from crude fecal material. Using either fresh or formaldehyde-fixed feces as sources of viable and nonviable oocysts, respectively, we fractionated the samples on parallel discontinuous sucrose gradients and evaluated oocyst viability at different banding densities by an in vitro excystation assay. The formaldehyde-inactivated fecal samples formed no bands after centrifugation and 91.66% of the oocysts became concentrated in the pellet. Fresh fecal samples formed three bands at densities 1.062, 1.092, and 1.121, in addition to a sediment. Here the viability of the gradient-sedimented oocysts was 92.3% overall, and of those in the second band 100%. Modifications in oocyst permeability thus seems to alter their sedimentation characteristics so that consequent distribution on sucrose gradients can be correlated with oocyst viability. Discontinuous sucrose density gradient sedimentation would thus constitute a simple and rapid mean to obtain viable oocysts for use in biological models both in vivo and in vitro.

Animals↗
PubMedDate not supplied

Mesenteric arterial steal syndrome secondary to bilateral lumbar sympathectomy.

A case of acute mesenteric ischemia and massive intestinal infarction secondary to bilateral lumbar sympathectomy and without any other apparent precipitating factors is presented. Its characteristics and findings significantly agree with those described as part of the mesenteric arterial steal syndrome. Although this syndrome was originally described as secondary to surgical revascularization of the lower extremities, experimental studies have shown that lumbar sympathectomy, by means of reducing the peripheral vascular resistance in the lower extremities, similarly causes intense hemodynamic alteration of the mesenteric circulation due to the sudeen redistribution of blood flow to the lower limbs at the expense of the mesenteric flow. When marginally compensated occlusive mesenteric arterial disease exists prior to surgery, the sudden fall in the arterial pressure gradients in this vessel can precipitate the occlusion of these arteries, resulting in mesenteric ischemia and intestinal infarction. It has also been suggested that an intense vasospamodic neurogenic reflex in the mesenteric arteries is an important factor in the pathogenesis of this syndrome.

Colon↗