Search PubMed⌕ Search

Biomedical subjects

J Alonso

Publications and source records attributed to J Alonso.

At least 271 records · Page 15Linked to original sources
PubMed1983

Oxygen therapy in pneumatosis coli. What is the minimum oxygen requirement?

Breathing high concentrations of oxygen at atmospheric pressure has been effective in achieving prompt objective and subjective relief in pneumatosis coli. A 22-year-old man was treated with 40% oxygen--a smaller concentration than used by previous physicians--supplied through a nonrebreathing mask. During meals, oxygen was given at 5 1/minute by nasal cannula. Oxygen therapy was maintained for seven days. A year after treatment the patient was still asymptomatic and free from disease. Using this therapeutic measure the benefit/risk ratio of oxygen therapy could be increased.

Adult↗
PubMed1978

[Mortality by burns in children (author's transl)].

The mortality rate among 1,490 children, aged zero to fourteen years, hospitalized in the Burns Unit of Departament of Plastic Surgery in Ciudad Sanitaria de la Seguridad Social de Sevilla is studied. Analysis determined death probabilities for each case according to percentage of burned surface and age, and also LD50 in different age groups. The mortality analysis showed lethal factors related with primary care and evacuation, responsible for a decrease in survival probabilities of the children. Children with severe burns must be hospitalized in special units, which must have a high level of training in hydroelectrolitics disturbances and surgical management of this type of patients, who require homo or xenografts frequently.

Adolescent↗
PubMed1977

Scanning electron microscopic and X ray microanalysis study of the mineral deposits in pseudoxanthoma elasticum.

A skin biopsy of a 37 year old man with typical lesions of pseudoxanthoma elasticum (P.E.) associated with angioid streaks (Groenbald-Strandberg Syndrom) was examined with a scanning E.M. (SEM) and a SEM provided with a X ray micro-analyser. The SEM provided with X ray microanalyser enabled us to see the correspondence between the crystalline deposits and a calcium salt. The potassium, sodium and magnesium analysis of the specimen permits us to verify that the P.E. dermis is rich in K and poor in Mg.

Adult↗
PubMed1977

[Groenblad-Strandberg syndrome. Study with scanning microscopy provided with an X rays analyzer].

A skin biopsy a 37 year old man with typical lesion of pseudoxanthoma elasticum associated with angioid striae (Groenblad-Strandberg syndrome) was examined with a scanning EM (SSM-2A) and a scanning EM provided with a X ray microanalyser. With the scanning EM (SSM-SA) it was possible to see tabular crystalline deposits with subround faces and rhombohedric tendency. The scanning EM provided with a X ray microanaliser enabled us to see crystalline deposits which in some fields adopt a star-shaped form corresponding to calcium crystals of not very well defined habit. The X ray microanalyser shows us the correspondence between the star shaped figures and a calcium salt. The potassium, sodium and magnesium analysis of the specimen permits us to verify that the pseudoxanthoma elasticum dermis is rich in K and poor in Mg.

Adult↗
PubMedDate not supplied

Towards a method for automated classification of 1H MRS spectra from brain tumours.

Recent studies have shown that MRS can substantially improve the non-invasive categorization of human brain tumours. However, in order for MRS to be used routinely by clinicians, it will be necessary to develop reliable automated classification methods that can be fully validated. This paper is in two parts: the first part reviews the progress that has been made towards this goal, together with the problems that are involved in the design of automated methods to process and classify the spectra. The second part describes the development of a simple prototype system for classifying 1H single voxel spectra, obtained at an echo time (TE) of 135 ms, of the four most common types of brain tumour (meningioma (MM), astrocytic (AST), oligodendroglioma (OD) and metastasis (ME)) and cysts. This system was developed in two stages: firstly, an initial database of spectra was used to develop a prototype classifier, based on a linear discriminant analysis (LDA) of selected data points. Secondly, this classifier was tested on an independent test set of 15 newly acquired spectra, and the system was refined on the basis of these results. The system correctly classified all the non-astrocytic tumours. However, the results for the the astrocytic group were poorer (between 55 and 100%, depending on the binary comparison). Approximately 50% of high grade astrocytoma (glioblastoma) spectra in our data base showed very little lipid signal, which may account for the poorer results for this class. Consequently, for the refined system, the astrocytomas were subdivided into two subgroups for comparison against other tumour classes: those with high lipid content and those without.

Brain Neoplasms↗
PubMedDate not supplied

1H NMR spectroscopy of colon tumors and normal mucosal biopsies; elevated taurine levels and reduced polyethyleneglycol absorption in tumors may have diagnostic significance.

Twenty-three pairs of normal mucosa and colonic adenocarcinoma biopsy specimens have been examined in this pilot study by 1H NMR spectroscopy at 9.4 T to determine whether it was possible to find spectral malignancy markers. The 3.2 ppm (trimethylamine-containing compounds)/0.9 ppm (methyl of fatty acids) resonance intensity ratio in water suppressed spectra, proposed by other authors as a malignancy marker, results in our hands, using resonance areas, in partial overlap between tumor and mucosa values, which reduces its diagnostic value. Furthermore, we have found that submucosa contamination could mask the normal mucosa pattern and artifactually decrease the 3.2/0.9 ppm, ratio value by increasing the 0.9 ppm resonance due to the known triglyceride content of normal submucosa. On the other hand, we have observed in the Hahn spin-echo spectra of intact biopsies resonances arising from taurine and exogenous polyethyleneglycol (PEG). Their assignment and quantification has been carried out in perchloric acid extracts of the tissue biopsies. The taurine (3.4 ppm)/creatine (3.0 ppm) area ratio produced an excellent discrimination between normal mucosa and tumour groups while the PEG (3.7 ppm)/creatine (3.0 ppm) area ratio presented a large overlap, although it was clearly higher in the mucosae than in the tumors for paired samples. These two NMR observable parameters are in our hands highly discriminating and are accordingly proposed as malignancy markers in tissue biopsies although their possible utility for in vivo studies remains to be demonstrated.

Adenocarcinoma↗
PubMedDate not supplied

Preoperative testing practice in healthy cataract surgery patients. Results of a survey of ophthalmologists in Barcelona, Spain. Barcelona I-PORT Investigators.

AIMS/BACKGROUND: Many preoperative ophthalmic and medical tests lack proven effectiveness in the evaluation of cataract surgery patients. Variation in use has been described in the USA, but little information is available for countries with different health systems. The objectives of the study were to assess variation in ophthalmologists' use of preoperative testing on cataract surgery patients and to identify ophthalmologists' characteristics associated with it. METHODS: A postal survey was made in a representative sample (response rate of 70%) of the Barcelona Medical Association of Ophthalmologists performing cataract surgery during 1993 (N = 89). The questionnaire included information about common preoperative, intraoperative and postoperative practice and sociodemographic and professional data. Appropriateness of preoperative ophthalmic tests was classified in 3 levels (indicated tests, tests with unproven benefit, and non-indicated tests) according to recommendations of the Cataract Management Guideline Panel [1] and the American Academy of Ophthalmology Preferred Practice Pattern [2]. RESULTS: Almost all the ophthalmologists reported performing Fundus exam plus A-scan in the preoperative evaluation of cataract surgery patients (indicated tests). Up to 20% reported performing 'frequently' or 'always' some non-indicated or unproven benefit ophthalmic tests. Additionally, an average of 7 medical tests were 'routinely' included. Private practice and cataract subspeciality were the ophthalmologists' characteristics more frequently associated with the use of inappropriate ophthalmic tests (p < 0.05). CONCLUSIONS: In Barcelona, Spain, some ophthalmic tests of unproven effectiveness are frequently performed preoperatively on cataract surgery patients without ocular comorbidity. Also, a generalized utilization of several medical tests was reported. There is potential for some cost containment and more appropriate care of cataract patients without diminishing the quality of care, in a location with low surgery rates.

Adult↗
PubMedDate not supplied

Intracoronary infusion of superoxide dismutase and reperfusion injury in the pig heart.

The effects of an intracoronary infusion of superoxide dismutase on infarct size were studied in 16 pigs submitted to a 48-min coronary occlusion of the mid left anterior descending coronary artery followed by reperfusion for 24 h. Areas at risk marked with fluorescein and infarct sizes calculated with triphenyl tetrazolium chloride staining 24 h after the occlusion were similar in the five control animals with coronary reperfusion alone, in the five animals with an intracoronary infusion of lactate Ringer initiated 3 min before reperfusion and maintained for 33 min and in the six animals with superoxide dismutase added to the solution of lactate Ringer and infused at a rate of 2500 units/min. The ratios infarct size/area at risk were respectively 0.50 +/- 0.10, 0.65 +/- 0.04 in the three study groups (NS). The extent of intramyocardial hemorrhage, evaluated by morphometric analysis was also similar 0.90 +/- 0.29 x 10(6), 0.70 +/- 0.14 and 1.62 +/- 0.42 red blood cells/mm3 of tissue (NS). The superoxide dismutase infusion, however, resulted in significantly fewer early reperfusion arrhythmias which involved 23 +/- 15 s of each minute electrocardiographic recording in the superoxide dismutase group, compared to 37 +/- 13 s in the lactate Ringer group and 45 +/- 14 s in the control group (p = 0.004). The lack of an effect of intracoronary infusion of superoxide dismutase on infarct size suggests that in this experimental model, extracellular superoxide radicals generated during early reperfusion have no major role on myocardial cell necrosis and microvascular damage. Reperfusion arrhythmias were, however, reduced.

Animals↗