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S Avila

Publications and source records attributed to S Avila.

33 records · Page 2Linked to original sources
PubMed1993

[The usefulness of computerized axial tomography (CT) in establishing the composition of calculi].

Determining stone composition before extracorporeal lithotripsy can be potentially useful. A total of 90 calculi of 6 different chemical composition (calcium oxalate monohydrate, calcium oxalate dihydrate, magnesium ammonium phosphate, phosphate carbonate, uric acid and phosphate oxalate) were analyzed in vitro using computed tomography (CT). The mean, central, peripheral, maximum, minimum stone density and stone morphology were determined. At least in vitro, the serial analyses of the mean, minimum, central stone density and stone morphology permitted distinguishing these 6 types of calculi, although 53% of the calcium oxalate dihydrate calculi could not be distinguished from the phosphate oxalate stones.

Chi-Square Distribution↗
PubMed1993

[The usefulness of dual-energy radiographic densitometry (DO) in establishing the composition of calculi].

Dual-energy radiographic bone densitometry is utilized to determine the bone mineral content in patients with osteoporosis. The present in vitro experimental study investigated the usefulness of densitometry in determining stone composition and in evaluating the mineral and non mineral phases of the calculus. For the study we analyzed 114 calculi of 6 different chemical composition (calcium oxalate monohydrate, calcium oxalate dihydrate, magnesium ammonium phosphate, phosphate carbonate, uric acid and phosphate oxalate). The phosphate carbonate calculi had the highest mineral density, whereas the uric acid calculi had the lowest and contained more water. Although densitometry appears to be of little value in determining stone composition, it provides information on the mineral and non mineral phases of the calculus.

Absorptiometry, Photon↗
PubMed1993

[Extracorporeal lithofragmentation and of direct contact. Development of mathematical models for calculating the energy and predicting the fragmentation].

The present experimental 'in vitro' study pursues the development of mathematical equations which, prior to lithofragmentation, would allow to estimate the amount of energy required and to predict the degree of fragmentation for each of the different sources of energy. A total of 114 calculi with 6 different compositions were analyzed by conventional X-rays (Rx), computerized axial tomography (CT) and dual X-ray densitometry (DO). Calculi were then fragmented using 4 different types of energy: electrohydraulic (LEH), piezoelectric (LEP), ultrasounds (US) and pulse laser (LAS). The correlation between imaging techniques parameters on the one side, and the amount of energy used and degree of fragmentation obtained on the other one, allow with a multiple linear regression analysis, both to develop mathematical equations to estimate the amount of energy required, and to predict the fragmentation rate.

Biophysical Phenomena↗
PubMed1990

Brain tumours in south Brazil: a retrospective study of 438 cases.

All brain tumours diagnosed since 1967 in a University Hospital in the Southern region of Brazil were reviewed and clinical information concerning age, sex, symptoms and evolution were analysed. 88.1% of tumours were primary neoplasms and the rest secondary deposits. There was a male predominance and the second and fifth decades of life were the most affected. The main presenting symptoms were headache, vomiting, hemiparesis, loss of vision and epilepsy. The commonest tumour was of astrocytic origin (36.3%) amongst which the malignant ones, including glioblastoma multiforme, predominated. These tumours were frequent in the cerebral hemispheres (31.3%), particularly in the frontal lobes. The time of evolution from the beginning of the clinical manifestations until the first hospital admission was also studied. The authors discuss the clinical and pathological observations in relation to other large series analysed in the literature.

Adolescent↗
PubMed1989

Factors affecting mortality in patients over 70 years of age submitted to surgery for gallbladder or common bile duct stones.

Chile is the country with the highest incidence of gallstone disease in the world. Nearly 44% of the women and 25% of the men over 20 years of age have gallstones. Biliary tract surgery accounts for about 35% of all the operations performed in Chilean general hospitals. The present paper aims at assessing the risk factors associated with a higher mortality in patients over 70 years of age subjected to elective or emergency surgery for gallstones or common bile duct stones. No specific factors of mortality were found in the group of elderly patients subjected to elective cholecystectomy. There was also no correlation between types of cholecystitis and postoperative mortality. However, acute suppurative cholangitis made the postoperative mortality rate increase almost 20-fold in patients with common bile duct stones. The mortality also shows a steep increase (up to 12%) if cholecystectomy is performed in acute cholecystitis. Cholecystostomy seems to be associated with a low mortality risk and hence should be appropriate in exceptionally high-risk patients, but is not considered useful by the authors in necrotic or gangrenous cholecystitis, or in cases with common bile duct stones and cholangitis. Postoperative mortality in patients submitted to cholecystectomy alone seems to depend exclusively on the concomitant presence of medical complications, mainly of a respiratory and cardiovascular nature. Septic complications are important causes of postoperative mortality in emergency cholecystectomy. Patients at high surgical risk are those suspected of cholangitis, those over 80 years of age, and those suffering from Charcot's triad, anemia, uremia, leukocytosis, hyperbilirubinemia or hypoprothrombinemia; in these, an endoscopic procedure could be chosen.

Age Factors↗
PubMedDate not supplied

The effect of liver transplantation on circulating levels of estradiol and progesterone in male patients: parallelism with hepatopulmonary syndrome and systemic hyperdynamic circulation improvement.

The correction of hepatopulmonary syndrome (HPS) after liver transplantation (LT) remains controversial. The aims of our study were to: 1) analyze whether LT reverses HPS; 2) note any relationship between HPS and the systemic hemodynamic disturbance; and 3) note changes in circulating sex hormones and the possible association with pulmonary and systemic hemodynamic changes. Systemic hemodynamic parameters, cardiac output and systemic vascular resistance (SVR), sex hormones, and intrapulmonary vasodilatation assessed by contrast transesophageal echocardiography, and gas exchange abnormalities were investigated in 19 patients with advanced cirrhosis prior to and 6 months (176.8+/-30 days) after LT. LT was followed by a marked reduction in cardiac output (6.6+/-1.7 vs 3.5+/-0.5 l/min; p<0.001) and SVR (1039+/-460 vs 1978+/-294 dyn x sec x cm(-5); p<0.005). Before LT, circulating estradiol and progesterone levels were invariably elevated (66+/-22 pg/ml and 1.8+/-1.1 ng/ml, respectively, normal values <31 pg/ml and 0.35 ng/ml, respectively), and dropped after LT (28+/-12 pg/ml p<0.001 and 0.38+/-0.2 ng/ml; p<0.001, respectively). Seventeen of 19 patients had intrapulmonary vasodilatation and increased alveolar-arterial oxygen difference, thereby fulfilling diagnostic criteria for HPS. Patients with HPS presented higher cardiac output (p<0.05), lower SVR (p<0.01), and higher progesterone and estradiol levels than patients without HPS (p<0.05). LT produced normalization of intrapulmonary vasodilatation in all patients. LT normalized hyperdynamic circulation and is a useful therapeutic option in patients with HPS. Normalization of sex hormone levels after LT suggests that they could play a pathogenic role in the development of HPS.

Blood Gas Analysis↗
PubMedDate not supplied

Congenital hemangioma with milialike structures: a case report.

A 4-month-old infant had two 3 cm x 4 cm hemangiomatous lesions on the scalp and back, present since birth, which contained peculiar white-yellowish small nodules. Histologically the lesions proved to have a hemangiomatous (capillary-type) component together with small keratin-containing epidermal cysts (milia-like) which progressively extruded their contents. The lesions also contained embryonic-like hair structures. The hemangiomas resolved spontaneously. We were unable to find any reference in the literature describing this peculiar combination of features.

Back↗
PubMedDate not supplied

[Comparative analysis of lithiasic fragmentation induced by extracorporeal and direct contact sources].

An in vitro experimental study on stone fragmentation was conducted on 114 calculi analyzed by infrared spectrophotometry. Four energy sources were utilized: electrohydraulic, piezoelectric, ultrasound and pulsed laser. We analyzed stone susceptibility to fragmentation (particles < 3 mm), pulverization (particles < 1 mm) and stone fragility (amount of energy/mg of calculus fragmented into particles < 3 mm) for each type of energy source of each of the following 6 stone compositions: calcium oxalate monohydrate, calcium oxalate dihydrate, magnesium ammonium phosphate, phosphate carbonate, uric acid and phosphate oxalate. The calcium oxalate dihydrate calculi were the most susceptible to fragmentation and the infective calculi (magnesium ammonium phosphate and phosphate carbonate) were the most susceptible to pulverization. The piezoelectric energy showed the highest capacity for fragmentation and pulverization of calculi. Stone fragility depended on each stone type and the energy source utilized.

Humans↗