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Biomedical subjects

A Torres

Publications and source records attributed to A Torres.

At least 379 records · Page 21Linked to original sources
PubMed1997

[Surgical treatment of diffuse hyperthyroid goiter. Experience at a hospital in Valdivia, Chile].

BACKGROUND: The choice of medical, radiation or surgical therapy for hyperthyroid diffuse goiter is still empirical. AIM: To report a retrospective analysis of the surgical treatment of hyperthyroid goiter in a Regional Hospital in Chile. PATIENTS AND METHODS: The charts of 64 patients, 54 female, aged between 15 and 57 years old, operated between 1985 and 1995 were analyzed. RESULTS: The indication for surgical treatment was failure of medical treatment in 59 patients and a big goiter causing mechanical compression in 3 patients. A subtotal thyroidectomy was done after an abbreviated surgical preparation. The mean weight of the resected glands was 65.9 g. Four patients had transient hypocalcemia and 4 had surgical wound seromas. After a mean follow up of 31 months, 77% of patients remain euthyroid, hyperthyroidism relapsed in 13.1% and 10% became hypothyroid. CONCLUSIONS: Surgical treatment of hyperthyroid goiter is safe but the percentage of hyperfunction relapse is high.

Adolescent↗
PubMed1997

[Contribution to the morphological knowledge of the articulations of the human tympanic ossicular chain].

The structure of human tympanic bones and their articulations was studied. Martin's trichrome stain of serial sections revealed the transmission paths of force lines based on bone lamellae density and acid fuchsin staining, which disclosed functional "critical points" (mechanical solicitation). This study contributed basic knowledge and a morphological and functional classification of the incudomalieotar and incudostapedial joints. The incudomalieolar joint was confirmed as a "riding saddle" but the incudostapedial joint as a "spheroid joint" was questioned. Information on capsule structure the meniscus and articular cartilage of the incudomalleolar joint is given.

Bone Density↗
PubMed1997

Effects of ozone on normal and potentially sensitive human subjects. Part II: Airway inflammation and responsiveness to ozone in nonsmokers and smokers.

Exposure to ozone at levels near the National Ambient Air Quality Standard causes respiratory symptoms, changes in lung function, and airway inflammation. Although ozone-induced changes in lung function have been well characterized in healthy individuals, the relationship between airway inflammation and changes in pulmonary function have not been prospectively examined. The purpose of this study was to determine whether individuals who differ in, lung function responsiveness to ozone also differ in susceptibility to airway inflammation and injury. A secondary goal was to determine whether ozone exposure induces airway inflammation in smokers, a population known to have airway inflammation and an increased burden of toxic oxygen species. Healthy nonsmokers (n = 56) and smokers (n = 34) were exposed to 0.22 parts per million (ppm)* ozone for 4 hours, with intermittent exercise, for the purpose of selecting ozone "responders" (decrement in forced expiratory volume in 1 second [FEV1] > 15%) and "nonresponders" (decrement in FEV1 < 5%). Selected subjects then were exposed twice to ozone (0.22 ppm for 4 hours with exercise) and once to air (with the same exposure protocol), each pair of exposures separated by at least 3 weeks, in a randomized, double-blind fashion. Nasal lavage (NL) and bronchoalveolar lavage (BAL) were performed immediately after one ozone exposure and 18 hours after the other, and either immediately or 18 hours after the air exposure. Indicators of airway effects in lavage fluid included changes in inflammatory cells, proinflammatory cytokines, protein markers of epithelial injury and repair, and generation of toxic oxygen species. In the classification exposure, fewer smokers than nonsmokers were responsive to ozone (11.8% vs. 28.6%, respectively); an insufficient number of smoker-responders were identified to study as a separate group. In the BAL study, all groups developed a similar degree of airway inflammation, consisting of increases in interleukins 6 and 8 (maximal immediately after exposure), and increases in polymorphonuclear leukocytes (PMNs), lymphocytes, and mast cells (maximal 18 hours after exposure). The increase in PMNs was inversely correlated with age (p = 0.013), but gender, nonspecific airway responsiveness, and allergy history were not predictive of inflammation. Alveolar macrophage production of toxic oxygen species decreased after ozone exposure in nonsmokers; however, not in smokers. Findings from nasal lavage did not mirror lower airway inflammatory responses in these studies. We conclude that, in response to ozone exposure, smokers experienced smaller decrements in lung function and fewer symptoms than nonsmokers; however, the intensity of the airway inflammatory response was independent of smoking status or airway responsiveness to ozone. Furthermore, the burden of toxic oxygen species following ozone exposure was greater for smokers than for nonsmokers. Subjects were young, healthy, and able to sustain exercise; the results may not be representative of nonsmokers or smokers in general. Nevertheless, the findings indicate that measuring symptoms and spirometric changes is not sufficient to assess the potential risks associated with ozone exposure.

Adolescent↗
PubMed1997

[Effects of vasectomy on the testicular structure of the dog].

Study of the effect on testis structure in the dog caused by a vasectomy. Emphasis is made on how in animals undergoing ligature of both ends of the ductus deferens, existence of structural changes, which are consistently present, are proportional to the time elapsed from performance of vasectomy. Such changes are revealed by: degeneration of germinal epithelium, thickening of basal membrane and hypertrophy of interstitial tissue at the expense of unspecific connective tissue. Changes were first seen as from the fourth month, but a full year has to elapse prior to noting a marked germinal hypoplasia. These experimental results cast doubts on the safety of such sterilization approach, although they cannot be entirely extrapolated to humans.

Animals↗
PubMed1997

Health evaluation of black-faced impala (Aepyceros melampus petersi) using blood chemistry and serology.

As part of ongoing ecological studies of black-faced impala (Aepyceros melampus petersi) in northern Namibia, blood samples were collected and analyzed from 26 animals captured for translocation in 1992. All animals appeared to be in good condition and no abnormality was noted during physical examination. Serum chemistry and mineral levels were measured and correlated with the results of bacterial and viral serology and were within the normal ranges for domestic ruminants. Antibody titers for infectious bovine rhinotracheitis and bovine viral diarrhea were detected. Serological tests for bluetongue, foot-and-mouth disease, rinderpest, parainfluenza 3, brucellosis, leptospirosis, and anaplasmosis were negative. Significant differences in disease prevalence were not found between sexes.

Animals↗
PubMed1996

Acute effects of digitalis and enalapril on the neurohormonal profile of chagasic patients with severe congestive heart failure.

Chagasic patients with congestive heart failure are usually treated with digitalis and converting enzyme inhibitors. According to the neurogenic and dysautonomic theories, chagasic patients would not benefit from these drugs. To clarify this controversial issue, we have studied patients with congestive heart failure and suspected Chagas' heart disease. All patients received intravenous methyl-digoxin for 24 h and oral enalapril for 96 h. Blood samples for plasma norepinephrine, aldosterone and renin were taken at baseline, after acute digitalization and following enalapril. Based on the serology for Chagas' disease, the patients were divided into non-chagasic and chagasic patients. In the chagasic group three patients were in functional class III and 3 were in functional class IV. In the non-chagasic group five patients were in functional class III and 2 were in functional class IV. Both groups had a marked and quantitatively similar degree of neurohormonal activation. All patients improved at least one functional class and lost more than 5 kg of body weight with treatment. The chagasic patients had a statistically significant reduction in plasma norepinephrine (2262 +/- 1407 to 865 +/- 390, P < 0.008, pg/ml, M +/- S.D.), plasma aldosterone (330 +/- 168 to 155 +/- 75, P < 0.01, pg/ml, M +/- S.D.) and plasma renin activity (14 +/- 13 to 2 +/- 1.6 ng/ml per h, M +/- S.D., P < 0.05), with digitalis. Following enalapril, norepinephrine and aldosterone there was a further but non-significant reduction, when compared to postdigitalis values. These results indicated that chagasic patients do benefit from digitalis and enalapril. Furthermore, the prominent and significant reduction in all three neurohormones suggest that the parasympathetic and sympathetic systems of these chagasic and non-chagasic patients, are responding to the neuromodulatory effects of digitalis and enalapril.

Aldosterone↗
PubMed1996

Analysis of the prognostic significance of cytosolic determination of CA 125 tumor-associated antigen, carcinoembryonic antigen and squamous cell carcinoma antigen in patients with nonsmall cell lung carcinoma.

BACKGROUND: The use of new prognostic factors as guidelines for the indication of treatment ancillary to surgery has been advocated for patients with nonsmall cell lung carcinoma (NSCLC). This article is an analysis of the prognostic information derived from determination of tumor-tissue cytosolic concentration of CA 125 tumor-associated antigen (CA 125), carcinoembryonic antigen (CEA), and squamous cell carcinoma antigen (SCC) in patients with NSCLC. METHODS: Tumor samples were obtained from 97 patients who successfully underwent surgery for NSCLC with curative intent. CA 125 and CEA were determined by enzyme immunoassay. SCC was determined by radioimmunoassay. The relationship between the tumor-tissue marker level and survival or likelihood of disease free survival was analyzed. RESULTS: Thirty-month survival post-treatment in patients registering CA 125 levels less than 26 U/mg was 68%, versus 30% among patients with levels of CA 125 greater tha 26 U/mg (P < 0.005). For SCC, these values were 57% and 39%, respectively (P = 0.07). No significant difference was seen for CEA (60% versus 44%; P = 0.3). Patients whose tumors had CA 125 levels lower than cutoff recorded a disease free survival rate of 61% versus 29% (P < 0.001); with SCC, likelihood of remaining free of tumor recurrence was 55% versus 34% (P < 0.05). Again, no significant difference was seen for CEA (49% versus 45%; P = 0.5). For CA 125 and SCC, the relationship between marker level and outcome held only with the most favorable histologic types. For CA 125 however, this relationship also held for Stage I tumors (P < 0.005). CONCLUSIONS: Ascertainment of concentrations of CA 125 and SCC in tumor tissue is useful parameter in the determination of postoperative prognosis for patients with NSCLC.

Adult↗
PubMed1996

Comparison of total resistive work of breathing in two generations of ventilators in an animal model.

Spontaneous breathing through an endotracheal tube and ventilator circuit is associated with an increased work of breathing (WOB). Recently, pediatric ventilators have introduced improved features to optimize patient-ventilator interactions. We performed an experiment utilizing an animal model to compare total resistive WOB of two widely used ventilators, the Siemens Servo Ventilator 300 (SV300) with patient-optimized features, such as flow-triggering and rapid response time, and the Siemens 900C (S900C) without those features. A total of 120 experiments of 10 minutes duration each were performed in 6 anesthetized, intubated lambs. In each experiment, the animal was randomized to either pressure support ventilation (PSV) of 5 cm H2O, or continuous positive airway pressure (CPAP) with 0 cmH2O end expiratory pressure (ZEEP) while supported by the SV300 or the S900C. Each animal was used as its own control. WOB was measured with a Bicore monitoring device as WOB of the animal (WOBp), WOB of the ventilator (WOBv), and the pressure time product (PTP) for each breath during the experiment. Oxygen consumption (Vo2) of the animal was measured using breath-by-breath gas analysis with a customized metabolic monitoring system. A Wilcoxon signed rank sum test was used for analysis. All comparisons between the ventilators for both CPAP and PSV showed a statistically significant difference (p < 0.001). WOBp was reduced by 47% during pressure support ventilation (PSV) and by 47% during CPAP when the SV300 was used compared to the S900C. We conclude that WOB is significantly lower in animals ventilated with the SV300 than with the S900C ventilator, and we speculate that ventilators with the features of the SV300 may offer advantages in ventilating pediatric patients.

Airway Resistance↗
PubMed1996

Effectiveness of microwave based digestion procedures for the demineralization of human milk and infant formulas prior to fluorometric determination of selenium.

The use of two types of microwave oven, one domestic (A) and the other specially designed for laboratory (B) for microwave-based digestion, to destroy the organic matter in milk and infant formulas prior to fluorometric determination of selenium is studied in order to check their applicability and reliability. In both systems the best results were obtained using the acid mixture HNO3-H2O2, and additional treatment with perchloric acid (60%) in a Thermoblock. The application of two different microwave-based digestion procedures to infant formulas was free of interferences. In the case of human milk, it was necessary to use the standard addition method. Values obtained for detection and quantification limits, precision and accuracy of the fluorometric determination of selenium show the usefulness of both digestion procedures. The oven designed for laboratory use (B) is preferential as it permits simultaneous digestion of eight samples.

Female↗
PubMed1996

Direct effect of phosphorus on PTH secretion from whole rat parathyroid glands in vitro.

Phosphorus retention is an important factor in the development of hyperparathyroidism secondary to renal failure. In vivo manipulation of phosphorus is associated with changes in serum calcium and calcitriol levels which in turn can modify parathyroid hormone synthesis and secretion. The present in vitro study evaluates whether high extracellular phosphorus has a direct effect on parathyroid hormone secretion. Fresh rat parathyroid glands were incubated in a media with phosphorus concentrations of 1, 2, 3, and 4 mM and subsequently exposed to calcium levels ranging from 0.4 to 1.35 mM. In 1.25 mM calcium, the parathyroid hormone secretion rate was similar in 1 and 2 mM phosphorus; however, a phosphorus concentration of 3 and 4 mM produced a 3- and 4-fold increase in the parathyroid hormone secretion, respectively, as compared with 1 mM phosphorus. While in 1 or 2 mM phosphorus an increase in calcium from 0.6 to 1.35 mM reduced parathyroid hormone secretion to 37%, in 4 mM phosphorus the same increase in calcium only inhibited parathyroid hormone secretion to 75%. Furthermore, the addition of arachidonic acid 20 microM, a substrate for inhibitory intracellular signal pathway, to the 4 mM phosphorus-1.35 mM calcium incubation media reduced the parathyroid hormone secretion to 34.5% (p < 0.05). In conclusion, our results indicate that in vitro, high phosphorus directly increases parathyroid hormone secretion.

Analysis of Variance↗
PubMed1996

Reduction of thrombotic and hemorrhagic complications after stent implantation.

This study compared two consecutive antithrombotic strategies after Palmaz-Schatz stent implantation and involved 918 patients. Patients treated between May 1991 and May 1994 (group 1; n = 379) received aspirin, dipyridamole, and intravenous unfractionated heparin until oral anticoagulation was effective, between June 1994 and August 1995, 539 patients (group 2) were treated for 1 month with subcutaneous low-molecular-weight heparin (Fragmin), ticlopidine, and aspirin. There were no differences between the groups in terms of sex, clinical condition, vessel diameter, and severity and location of stenosis. Patients in group 1 were younger than those in group 2 (4% were > 70 years old compared with 12%, respectively; p < 0.01). Group 1 patients had more frequent unplanned stenting (48% vs 18%, respectively; p < 0.01) and fewer endoprostheses in the same artery than those in group 2 (1.1 +/- 0.5 vs 1.2 +/- 0.5, respectively; p < 0.01). Among group 2 patients, there was a significant reduction in thrombotic and hemorrhagic complications compared with group 1 patients. No subacute thrombosis occurred in patients in group 2 in contrast with a 5.8% incidence in patients in group 1 (p < 0.01). In addition, a lower incidence of groin and systemic bleeding was observed in patients in group 2 compared with patients in group 1 (2.6% vs 15%, respectively; p < 0.01). The association of low-molecular-weight heparin and antiplatelets provides a simpler antithrombotic strategy in patients treated with intracoronary stents and reduces the incidence of stent thrombosis and hemorrhagic complications. Our findings suggest that this antithrombotic regimen may prevent or completely avoid stent thrombosis.

Acute Disease↗
PubMed1996

Relationship between ventilator-associated pneumonia and intramucosal gastric pHi: a case-control study.

PURPOSE: Prior investigations have suggested a clear relationship between nosocomial pneumonia and intramucosal gastric pH (pHi), a probable marker of bacterial translocation. METHODS: We studied 33 patients (18 with pneumonia and 15 without) admitted to an intensive care unit and hospitalized longer than 72 hours with the aim of assessing the relationship between nosocomial pneumonia, pHi, and outcome. pHi was estimated at the time of inclusion of patients into the study. Arterial pH (pHa) and bicarbonate and stomach pH and tonometer PtCO2 were also recorded. Values of < 7.32 or delta pHa-pHi of > +0.06 were used to differentiate between normal and low pHi. Quantitative cultures of pharyngeal swabs, gastric lumen, and protected specimen brush from lower airways were also done. RESULTS: The mean pHi values were 7.397 +/- 0.105 (range, 7.14 to 7.53) and 7.452 +/- 0.059 (range, 7.37 to 7.56) for patients with and without pneumonia, respectively (P = .073). Five patients, all with pneumonia, had pHi < 7.32. No patients without pneumonia had pHi < 7.32 (P = .04). The mean delta pHa-pHi was 0.04 +/- 0.07 (range, -0.11 to 0.13) and 0.05 +/- 0.09 (range, -0.09 to 0.28; P = .72) for patients with and without pneumonia, respectively. However, there were significant differences when tonometer PtCO2 values of both groups were compared (38.9 +/- 8.3 and 30.6 +/- 4.7 mm Hg, respectively; P = .025). Patients with pneumonia had higher alkaline gastric lumen pH (5.2 +/- 1.0) than those without pneumonia (3.8 +/- 1.4; P = .006). Nonsurvivors (n = 7) had more acidic pHi (7.33 +/- 0.11) than survivors (7.44 +/- 0.06; P = .045). The mean gastric lumen bacterial concentration was 4.14 +/- 1.01 Log10 CFU/mL in patients with pneumonia and 4.28 +/- 1.22 Log10 CFU/mL in patients without pneumonia (P = NS). When patients with and without intramucosal gastric acidosis (pHi < 7.32) were compared, the gastric bacterial burden was 4.42 +/- 0.82 Log10CFU/mL and 4.32 +/- 1.03 Log10 CFU/mL (P = .08), respectively. CONCLUSIONS: Most patients with nosocomial pneumonia had no associated intramucosal gastric acidosis. However, low pHi was associated with increased mortality.

Adult↗
PubMed1996

Prediction of survival and recurrence by serum and cytosolic levels of CEA, CA125 and SCC antigens in resectable non-small-cell lung cancer.

Risk of death and risk of recurrence in 108 potentially curable non-small-cell lung cancer patients were analysed with respect of TNM stage, histological type and carcinoembryonic antigen (CEA), CA125 antigen and squamous cell carcinoma antigen (SCC) levels in serum and cytosol. CA125 and CEA levels were closely related to outcome figures. Multivariate analyses indicated that TNM stage and histological type had the best predictive power, but serum and cytosolic CA125 and serum CEA contained additional, independent prognostic information. Predictive information drawn from serum and cytosolic levels proved mutually complementary. We conclude that CA125 and CEA complement TNM classification and histological type for the purpose of quantifying risk of death or recurrence.

Adenocarcinoma↗
PubMed1996

Relative effects of PTH and dietary phosphorus on calcitriol production in normal and azotemic rats.

In moderate renal failure, the serum calcitriol level is influenced by the stimulatory effect of high PTH and the inhibitory action of phosphorus retention. Our goal was to evaluate the relative effect that high PTH levels and increased dietary phosphorus had on calcitriol production in normal rats (N) and rats with moderate renal failure (Nx). Normal and Nx (3/4 nephrectomy) rats were divided into two groups: (1) rats with intact parathyroid glands (IPTG) and (2) parathyroidectomized rats in which PTH was replaced (PTHR) by the continuous infusion of rat 1-34 PTH, 0.022 microgram/hr/100 g body wt, using a miniosmotic Alzet pump. To test the effect of dietary phosphorus, rats received either a moderate (MPD, 0.6% P) or a high phosphorus (HPD, 1.2%) diet for 14 days. The experimental design included pair-fed N and Nx rats with either IPTG or PTHR. Serum calcitriol and PTH levels in N rats fed a MPD were 69 +/- 3 and 40 +/- 5 pg/ml, respectively. In Nx rats on a MPD, serum calcitriol levels decreased only if hyperparathyroidism was not allowed to occur (76 +/- 4 vs. 62 +/- 4 pg/ml in Nx-IPTG-MPD and Nx-PTHR-MPD groups respectively, P < 0.05). Even in N rats on a HPD, high PTH levels (67 +/- 8 pg/ml in the N-IPTG-HPD group) were required to maintain normal serum calcitriol levels (69 +/- 4 vs. 56 +/- 6 pg/ml in Nx-IPTG-HPD and Nx-PTHR-HPD groups, respectively; P < 0.05). In Nx rats on a HPD, the development of secondary hyperparathyroidism (286 +/- 19 pg/ml in the Nx-IPTG-HPD group) prevented a decrease in serum calcitriol levels (68 +/- 7 pg/ml). In contrast, serum calcitriol levels were low in the Nx-PTHR-HPD group (52 +/- 4 pg/ml, P < 0.05), which were deprived of the adaptative increase in endogenous PTH production. In conclusion, our results in rats indicate that in moderate renal failure, an elevated PTH level maintains calcitriol production and overcomes the inhibitory action of phosphorus retention.

Animals↗