Biomedical subjects

A Palomar

Publications and source records attributed to A Palomar.

At least 19 recordsLinked to original sources

PubMed2002

[Nasolacrimal stent: modifications to Ho-Young Song's technique].

PURPOSE: To introduce modifications to Song's technique in the treatment of nasolacrimal occlusion by means of a polyuretane stent. MATERIAL AND METHOD: Thirty five polyuretane stents were placed under fluoroscopic guidance in 32 patients diagnosed with total and partial nasolacrimal occlusion. CONCLUSION: Technical success rate was 90%. Sixteen right and nineteen left nasolacrimal systems were probed. The introduction of a guidewire through the lower punctum, the use of a Ritleng guide, a Crawford hook and ocular protectors are modifications of Song's procedure that may help in successfully performing this technique in a fast and easy way.

Adult↗

PubMed2001

Right ventricular ischemia in patients with primary pulmonary hypertension.

OBJECTIVES: The goal of this study was to determine whether right ventricular (RV) ischemia is a contributory factor in the development of RV dysfunction in patients with primary pulmonary hypertension (PPH). BACKGROUND: Patients with advanced PPH develop RV dysfunction, characterized by a decreased cardiac output, increased right atrial pressure (RAP) and/or elevated RV end-diastolic pressure, which progresses to heart failure and death. The cause of this dysfunction is unknown. Right ventricular ischemia may play a role in its development. METHODS: From 1992 to 1999, a prospective study involving 23 patients with PPH at the Instituto Nacional de Cardiologia "Ignacio Chavez" (Mexico City, Mexico) was undertaken. These patients were evaluated clinically and further studied by echocardiography, right heart catheterization and stress myocardial scintigraphy using technetium 99m sestamibi. RESULTS: Nine patients of 23 were found to have scintigraphic images consistent with RV ischemia. Significant correlation was found between RV ischemia obtained through myocardial perfusion scintigraphy and elevation of RV end-diastolic pressure (p < 0.001), elevation of RAP (p < 0.037) and a decrease in mixed venous oxygen saturation (p < 0.0001). No other clinical or hemodynamic variables showed a significant correlation with RV ischemia. CONCLUSIONS: A direct correlation exists between RV ischemia, as determined by myocardial scintigraphy, and hemodynamic alterations suggestive of RV dysfunction in patients with PPH.

Adult↗

PubMed1999

Effect of body position changes on pulmonary gas exchange in Eisenmenger's syndrome.

Preliminary studies on sleep of patients with congenital heart disease and Eisenmenger's syndrome (ES) at our institution demonstrated nocturnal worsening arterial unsaturation, which appeared to be a body position-related phenomenon. To investigate the potential effect of body position on gas exchange in ES, we carried out a prospective study of 28 patients (mean age, 34.8 +/- 11.7 yr) with established ES due to congenital heart disease. In every patient, arterial blood gases were performed during both sitting and supine positions under three different conditions: room air, while breathing 100% oxygen, and after breathing oxygen at a flow rate of 3 L/min through nasal prongs. Alveolar oxygen pressure (PaO2) for the calculation of alveolar-arterial oxygen tension differences (AaPO2) was derived from the alveolar gas equation using PaCO2 and assuming R = 1. We used paired t test, repeated-measures two-way ANOVA with Bonferroni's test, and regression analysis. From sitting to supine position on room air, there was a significant decrease in PaO2 (from 52.5 +/- 7.5 to 47.5 +/- 5.5 mm Hg; p < 0. 001) and SaO2 (from 86.7 +/- 4.6 to 83.3 +/- 4.9%; p < 0.001), both of which were corrected by nasal O2 (to 68.2 +/- 21 mm Hg and to 92 +/- 4%, respectively, p < 0.005). PaCO2 and pH remained unchanged. The magnitude of the change in PaO2 correlated with the change in AaPO2 on room air (r = 0.77; p < 0.01) but not with the change in AaPO2 on 100% oxygen. It is concluded that in adult patients with ES there is a significant decrease in PaO2 and SaO2 when they change from the sitting to the supine position. A ventilation-perfusion (V/Q) distribution abnormality and/or a diffusion limitation phenomenon rather than an increase in true shunt may be the mechanisms responsible for this finding. The response to nasal O 2 we observed warrants a trial with long-term nocturnal oxygen therapy in these patients.

Adult↗

PubMed1998

Graded balloon dilation atrial septostomy in severe primary pulmonary hypertension. A therapeutic alternative for patients nonresponsive to vasodilator treatment.

OBJECTIVES: We sought to investigate the acute hemodynamic effects of graded balloon dilation atrial septostomy (BDAS) and to define the long-term impact of this procedure on New York Heart Association functional class and survival in adult patients with primary pulmonary hypertension (PPH). BACKGROUND: Current treatment strategies for patients with severe and refractory PPH are limited by either technical difficulties and high mortality or cost. METHODS: We studied 15 patients with severe PPH. BDAS was successfully performed in all patients by crossing the interatrial septum with a Brockenbrough needle, followed by progressive dilation of the orifice with a Mansfield balloon in a hemodynamically controlled, step-by-step manner. RESULTS: BDAS caused an immediate significant fall in right ventricular end-diastolic pressure and in systemic arterial oxygen saturation and an increase in cardiac index. One patient died, and 14 survived the procedure and significantly improved their mean functional class (from 3.57 +/- 0.6 to 2.07 +/- 0.3 [mean +/- SD], p < 0.001). Exercise endurance (6-min test) also improved from 107 +/- 127 to 217 +/- 108 m (p < 0.001). Because of spontaneous closure, BDAS was repeated in four patients. The survival rate among patients who survived the procedure was 92% at 1, 2 and 3 years, which is better than that for historical control PPH patients (73%, 59% and 52%, respectively). CONCLUSIONS: With careful monitoring, BDAS is a safe and useful palliative treatment for selected patients with severe PPH.

Adult↗

PubMed1997

Prophylactic intravenous ondansetron in patients undergoing cataract extraction under general anesthesia.

During the past decade the demand for outpatient surgery has grown rapidly. Postoperative nausea and vomiting is one of the more common undesirable consequences of surgery, which may significantly delay the patient's discharge from the ambulatory surgery center. None of the currently used antiemetic drugs is considered totally effective in abolishing nausea or vomiting. The purpose of this study was to compare the efficacy of ondansetron, a highly selective 5-hydroxytryptamine subtype-3 receptor antagonist, with that of metoclopramide for the prevention of postoperative emesis in patients undergoing cataract surgery. The incidence of postoperative nausea was significantly less in the ondansetron group than that in the metoclopramide group (p = 0.046). Although the incidence of vomiting was clinically less frequent in the ondansetron group, there were no significant differences between both treatment groups. To our knowledge, this is the first study to demonstrate that ondansetron is effective to prevent postoperative emesis after extracapsular cataract extraction.

Adolescent↗

PubMed1996

Primary antiphospholipid syndrome presenting as chronic thromboembolic pulmonary hypertension. Treatment with thromboendarterectomy.

Pulmonary hypertension may occur in the antiphospholipid syndrome as a result of recurrent pulmonary embolism or microthrombosis of pulmonary vessels. We describe 3 cases of primary antiphospholipid syndrome (APS) and cor pulmonale that fulfilled the criteria for chronic major vessel thromboembolic pulmonary hypertension. Pulmonary thromboendarterectomy was performed in all 3 patients and it was successful in 2. One patient died in the immediate postoperative period from hemorrhagic pulmonary edema. Chronic thromboembolic pulmonary hypertension should be added to the list of pulmonary vascular complications of primary APS. Despite its risk, pulmonary thromboendarterectomy represents a treatment option for this otherwise lethal condition.

Adult↗

PubMed1995

Primary pulmonary hypertension in children: clinical characterization and survival.

OBJECTIVES: This study characterized mortality in a group of Mexican children (n = 18, mean [+/- SD] age 9.9 +/- 3 years) with primary pulmonary hypertension and investigated the factors associated with their survival. BACKGROUND: Primary pulmonary hypertension is a progressive, fatal disease of unknown cause. Establishing the diagnosis earlier in life may influence prognosis. METHODS: A dynamic cohort of children with primary pulmonary hypertension were enrolled between December 1977 and May 1991 and followed up through September 1992. Measurements included hemodynamic and pulmonary function variables in addition to demographic data, medical history and response to vasodilator treatment. We also compared the survival estimates of these children with those of our adult patients with primary pulmonary hypertension (n = 42, mean age 27.9 +/- 8.5 years). RESULTS: Baseline mean (+/- SD) pulmonary artery pressure was similar in children and adults (66 +/- 15 vs. 65 +/- 18 mm Hg, p = NS), but a higher cardiac index resulted in a lower mean pulmonary vascular resistance index in children (18 +/- 7 vs. 26 +/- 12 U/m2, p < 0.01). The proportion of patients who had a positive hemodynamic response to vasodilator treatment was higher in children than in adults (41% vs. 25%). Estimated median survival in children was 4.12 years (95% confidence interval [CI] 0.75 to 8.66) and 3.12 years in adults (95% CI 0.5 to 13.25, chi-square log-rank 0.81, p = NS). Elevated right atrial pressure (rate ratio 10.2) and decreased stroke volume index (rate ratio 32.9) were the only significant predictors of mortality (Cox proportional hazards model). CONCLUSIONS: Children with primary pulmonary hypertension have a poor survival expectancy, which does not appear to differ from that in adults with primary pulmonary hypertension. Mortality in childhood primary pulmonary hypertension is also associated with variables that assess right ventricular dysfunction.

Adult↗

PubMed1995

[Bilateral choroidal metastases of pancreatic carcinoma].

Pancreatic adenocarcinoma represents 2 to 5% of all the carcinomas. It is the fourth largest cause of death from cancer. It gives rise to metastasis of the liver, kidney, brain, etc. But choroidal metastasis are infrequent. We present the case of a male aged 45 years, who presented bilateral choroidal metastasis of pancreatic carcinoma.

Choroid Neoplasms↗

PubMed1994

Survival in primary pulmonary hypertension. Validation of a prognostic equation.

BACKGROUND: The prognosis of patients with primary pulmonary hypertension (PPH) remains a major problem for the planning and assessment of therapeutic interventions. The objectives of this study were (1) to characterize mortality in a Mexican population of patients with PPH and to investigate factors associated with survival and (2) to test the applicability in this population of the prognostic equation proposed by the US National Institutes of Health study on PPH. METHODS AND RESULTS: A dynamic cohort of patients with PPH at our institution were enrolled between June 1977 and August 1991 and prospectively followed at regular intervals through September 1992. Measurements at diagnosis included hemodynamic and pulmonary function variables in addition to information on demographic data and medical history. The response to vasodilator treatment was also analyzed. The estimated median survival of the group was 4.04 years (95% confidence interval, 2.98 to 5.08 years). Variables associated with poor survival (univariate analysis) included an elevated mean right atrial pressure, a decreased cardiac index, and a decreased mixed venous PO2. A reduced forced vital capacity and the absence of vasodilator treatment were also associated with poor survival. A multivariate Cox proportional-hazards regression analysis was used to assess the adjusted hazard ratios, hence the relative contributions of the variables controlling for confounding. Reduced forced vital capacity and cardiac index and increased right atrial pressure were still significantly associated as risk factors for survival in patients with PPH. Survival as computed by the equation correlated with real survival of PPH patients with positive predictive values of 87%, 91%, and 89% at 1, 2, and 3 years, respectively. The equation, however, was relatively unable to predict deaths in our population, in part because of the strict limits of poor prognosis. CONCLUSIONS: Mortality in PPH is largely associated with hemodynamic variables that assess right ventricular function. The proposed prognostic equation had a high sensitivity and a relatively low specificity to predict survival in our PPH population. To improve this specificity it may be necessary to increase the limits of poor prognosis as defined by the equation.

Adult↗

PubMed1993

Apoprotein A and A-I profiles in subretinal fluid.

Previous reports have described the presence of apoproteins A in subretinal fluid (SRF). We studied the presence of total apoprotein A (apo A) and apoprotein A-I (apo A-I), using the method described by Laurel in SRF and its levels in serum in 20 patients with retinal detachment. By this method we can quantify the concentrations of apoproteins in SRF. All cases showed the presence of these apoproteins in SRF. The mean +/- standard deviation obtained was 78.7 +/- 26.94 mg/dl and 173.35 +/- 30.08 mg/dl for total apo A in SRF and serum respectively. For apo A-I these values were 32.62 +/- 14.36 mg/dl in SRF and 123.4 +/- 24.11 mg/dl in serum. We found no correlation between levels of total apo A and apo A-I in SRF and its levels in serum. Statistical differences were found between apo A-I content in SRF from detachments with the size of 3 quadrants and that of 1 and 2 quadrants but not between 3 and 4 quadrants. When the detachment affected 1 and 2 quadrants the concentrations of apo A-I were statistically lower. No statistical differences were found between concentrations of total apo A and apo A-I in SRF and the duration or presence of PVR in the detachments. These findings suggest that the outer blood retinal barrier is preserved during rhegmatogenous retinal detachment.

Adult↗

PubMed1993

Levels of vancomycin in aqueous humor after topical eye drops administration.

Vancomycin is an antibiotic which is especially active against Gram positive bacteria. At present, numerous infections of the anterior segment of the eye are caused by the Staphilococcus aureus and epidermis. Strains which are resistant to methicilin are more and more frequent and for this reason Vancomycin is becoming the antibiotic of choice to combat these infections since no resistance of the Staphilococcus to it has been demonstrated. The authors evaluated the levels of Vancomycin in aqueous humor after the administration of topical eye-drops. For the first two hours after the last administration, levels of 0.52 micrograms/ml were detected. These inhibit the growth of the majority of bacteria sensitive to Vancomycin. Between two and four hours, the levels decreased to 0.15 micrograms/ml; these are therapeutic levels for a large number of Gram positive bacteria. From four hours after the last administration, these levels are undetectable. Due to the success of its penetration, topical administration of Vancomycin should be considered as a therapeutic modality against infections by gram positive bacteria of the anterior segment. The ideal guideline for administration would be one drop every two hours, especially if the infection is severe. In this way, subconjunctival injection could be avoided.

Anterior Eye Segment↗

PubMed1993

Fatal acute myocardial infarction after intravenous fluorescein angiography.

Since its introduction, fluorescein angiography has been widely used to investigate diseases of the ocular fundus. A case of fatal acute myocardial infarction after intravenous fluorescein angiography is presented. This appears to be the first case documented by autopsy in which the findings are compatible with myocardial infarction as the cause of death. Although there are no known contraindications for fluorescein angiography in patients with a history of cardiovascular disease, the indications for this elective procedure should be carefully reviewed in such patients. Adequate emergency resuscitation equipment should be available in the fluorescein angiography suite.

Aged↗

PubMed1993

Pulmonary arterial hypertension and cor pulmonale associated with chronic domestic woodsmoke inhalation.

We describe the clinical, radiologic, functional, and pulmonary hemodynamic characteristics of a group of 30 nonsmoking patients with a lung disease that may be related to intense, long-standing indoor wood-smoke exposure. The endoscopic and some of the pathologic findings are also presented. Intense and prolonged wood-smoke inhalation may produce a chronic pulmonary disease that is similar in many aspects to other forms of inorganic dust-exposure interstitial lung disease. It affects mostly country women in their 60s, and severe dyspnea and cough are the outstanding complaints. The chest roentgenograms show a diffuse, bilateral, reticulonodular pattern, combined with normalized or hyperinflated lungs, as well as indirect signs of pulmonary arterial hypertension (PAH). On the pulmonary function test the patients show a mixed restrictive-obstructive pattern with severe hypoxemia and variable degrees of hypercapnia. Endoscopic findings are those of acute and chronic bronchitis and intense anthracotic staining of the airways appears to be quite characteristic. Fibrous and inflammatory focal thickening of the alveolar septa as well as diffuse parenchymal anthracotic deposits are the most prominent pathologic findings, although inflammatory changes of the bronchial epithelium are also present. The patients had severe PAH in which, as in other chronic lung diseases, chronic alveolar hypoxia may play the main pathogenetic role. However, PAH in wood-smoke inhalation-associated lung disease (WSIALD) appears to be more severe than in other forms of interstitial lung disease and tobacco-related COPD. The patients we studied are a selected group and they may represent one end of the spectrum of the WSIALD.

Blood Pressure↗

PubMed1993

[Usher syndrome. Two case reports].

Usher's syndrome is an autosomal, recessively inherited trait that combines a congenital hearing impairment with retinitis pigmentosa. The AA. present the cases of two brothers affected. The actual classification and the last etiopathogenic theories are revised.

Adolescent↗

PubMed1993

[Size of incision and induced astigmatism in cataract surgery].

A study was carried out of postoperative astigmatism in three groups of 50 eyes which had had cataracts removed by phacoemulsification or by planned extracapsular removal through incisions of 3.5-4 mm, 7-7.5 mm, and 10-11 mm respectively. No statistically significant differences were observed in the average number of cases of astigmatism found 100 days after the operation in the patients in whom incisions of 10-11 mm (1.82 +/- 0.95 Dp) and 7-7.5 mm (1.78 +/- 0.90 Dp) were made. Appreciable differences were discovered when these two groups were compared with cases in which small incisions had been used and who presented a lower degree of astigmatism (1.02 +/- 0.59 Dp). To ensure less postoperative astigmatism after phacoemulsification, the size of the incision should be modified as little as possible during the insertion of the intraocular lens.

Adult↗

PubMed1993

Posttraumatic reaction in a case of fundus flavimaculatus with atrophic macular degeneration.

We report the case of a 13-year-old girl who had fundus flavimaculatus with atrophic macular degeneration. At the age of 14 years, she suffered mild trauma OD, subsequently developing a fibroglial reaction of the retina and pigmentary migration. The coexistence of both phenomena could be explained by the liberation of growth factors by the damaged retinal pigment epithelial (RPE) cells as a reaction to the injury and/or by the passage of chemoattractants from the serum through the damaged RPE cell barrier.

Adolescent↗

PubMed1992

Effect of hydralazine on vascular mechanics in a canine lobar preparation of pulmonary embolism.

We studied the effect of hydralazine (H) on pulmonary vascular mechanics in an isolated, in situ, canine lobe model of normal and increased pulmonary vascular resistance (Rp) produced by Gelfoam embolization (GE). Pulmonary pressure-flow (P-Q) curves from 24 lobes were obtained at baseline and after each intervention. Hemodynamic parameters for analysis included: the mean critical closing pressure (Ppai), vascular conductance (1/Rp), lobar flow (QL), and the pulmonary inflow pressure (Ppa) at different levels (50, 100, 200, 400, and 600 ml/min) of a fixed flow. After the preparation was stabilized, the 24 lobes were classified into 2 groups. For group 1 (n = 8) we studied the effect of H on the normal pulmonary vasculature. In group 2 (n = 16) we studied the effect of GE. Following GE, this group was further divided in half. For group 2A (n = 8) we followed the natural history of GE with measurements at 15 and 60 min. For group 2B (n = 8) measurements were done 15 min after GE and repeated again 15 min after the infusion of H. For group 1 lobes, H promoted a significant decrease (p less than 0.001) in Ppa at fixed flows of 200, 400, and 600 ml/min compared to baseline, with no change in Ppa for flows below 100 ml/min. QL and 1/Rp increased (p less than 0.01), and there was not any significant change in Ppai. In group 2A lobes, GE produced an increase in Ppa at all levels of flow (p less than 0.01), QL and 1/Rp decreased (p less than 0.05), and there was an increase in Ppai (p less than 0.05). These changes remained stable over the 60 min of observation. For group 2B lobes, GE produced the same hemodynamic changes as in group 2A, and the infusion of H caused a decrease in Ppa at flows between 100 and 300 ml/min. (p less than 0.01) with no change in Ppa at flows below 100 ml/min. QL and 1/Rp increased (p less than 0.01) and Ppai did not change compared to 15 min after GE. We conclude that in the normal canine pulmonary vasculature as well as in the model of GE, H decreased Rp and did not affect mean critical closing pressure, all of which may be explained by an increase in vascular conductance due to an increase in vascular distensibility.

Animals↗

PubMed1992

Central and peripheral corneal thickness in full-term newborns by ultrasonic pachymetry.

To establish a standard of normality, the authors studied the central and peripheral (superior, inferior, nasal, and temporal) corneal thickness of 152 healthy, white race, full-term newborns (304 eyes) between 1 and 6 days old, using ultrasonic pachymetry. The mean central corneal thickness (CCT) was 585 +/- 52 microns (ranging from 446-706 microns). The mean peripheral corneal thickness (PCT), significantly thicker than CCT (P = 0.0001), was: superior (SCT) 696 +/- 55 microns, inferior (ICT) 744 +/- 62 microns, nasal (NCT) 742 +/- 58 microns, and temporal (TCT) 748 +/- 55 microns. The SCT was significantly thinner than the ICT, NCT, and TCT (P = 0.0001). Differences among ICT, NCT, and TCT were not statistically significant. The mean CCT of the 1-day-old group was 611 +/- 58 microns, this being thicker than those of the other age groups (P = 0.0001). The differences between male and female babies and between right and left eyes were not statistically significant. This is the first study on peripheral corneal thickness at the limbus in the four meridians in live newborns.

Cornea↗