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Biomedical subjects

A Buendía

Publications and source records attributed to A Buendía.

At least 19 recordsLinked to original sources
PubMed2001

Effect of pH and soybean cultivars on the quantitative analyses of soybean rhizobia populations.

Quantitative analyses of fast- and slow-growing soybean rhizobia populations in soils of four different provinces of China (Hubei, Shan Dong, Henan, and Xinjiang) have been carried out using the most probable number technique (MPN). All soils contained fast- (FSR) and slow-growing (SSR) soybean rhizobia. Asiatic and American soybean cultivars grown at acid, neutral and alkaline pH were used as trapping hosts for FSR and SSR strains. The estimated total indigenous soybean-rhizobia populations of the Xinjiang and Shan Dong soil samples greatly varied with the different soybean cultivars used. The soybean cultivar and the pH at which plants were grown also showed clear effects on the FSR/SSR rations isolated from nodules. Results of competition experiments between FSR and SSR strains supported the importance of the soybean cultivar and the pH on the outcome of competition for nodulation between FSR and SSR strains. In general, nodule occupancy by FSRs significantly increased at alkaline pH. Bacterial isolates from soybean cultivar Jing Dou 19 inoculated with Xinjiang soil nodulate cultivars Heinong 33 and Williams very poorly. Plasmid and lipopolysaccharide (LPS) profiles and PCR-RAPD analyses showed that cultivar Jing Dou 19 had trapped a diversity of FSR strains. Most of the isolates from soybean cultivar Heinong 33 inoculated with Xinjiang soil were able to nodulate Heinong 33 and Williams showed very similar, or identical, plasmid, LPS and PCR-RAPD profiles. All the strains isolated from Xinjiang province, regardless of the soybean cultivar used for trapping, showed similar nodulation factor (LCO) profiles as judged by thin layer chromatographic analyses. These results indicate that the existence of soybean rhizobia sub-populations showing marked cultivar specificity, can affect the estimation of total soybean rhizobia populations indigenous to the soil, and can also affect the diversity of soybean rhizobial strains isolated from soybean nodules.

China↗
PubMed2001

Surgical treatment for secundum atrial septal defects in patients >40 years old. A randomized clinical trial.

We prospectively examined whether surgical treatment of secundum atrial septal defects (ASDs) in patients > or =40 years old improves their long-term clinical outcome. Surgical treatment of secundum ASDs in adults > 40 years old is a subject of controversy because of the perception of good long-term clinical outcomes in patients with unrepaired ASDs and the lack of data from randomized trials. We recruited 521 patients > 40 years old with secundum ASDs referred for treatment; 48 were excluded. Patients were randomly assigned to surgical closure (n = 232) or medical treatment (n = 241). The primary and secondary end points were a composite of major cardiovascular events (death, pulmonary embolism, major arrhythmic event, embolic cerebrovascular event, recurrent pulmonary infection, functional class deterioration or heart failure) and overall mortality, respectively. We assessed possible prognostic markers. The analysis was performed on an intention-to-treat basis. The median follow-up period was 7.3 years (range 2 to 13). The risk of having the primary end point was significantly higher in the medical group, which had a univariate hazards ratio of 1.99 (95% confidence interval [CI] 1.23 to 3.22) and a multivariate hazards ratio of 1.85 (95% CI 1.08 to 3.17). Although the survival analysis did not reveal differences in overall mortality between the surgical and medical treatments (hazards ratio 1.71, 95% CI 0.76 to 3.86), the multivariate analysis, adjusted by age at entry, mean pulmonary artery pressure and cardiac index, demonstrated significant differences between the study groups (hazards ratio 4.09, 95% CI 1.41 to 11.89). Surgical closure was superior to medical treatment in improving both the composite of major cardiovascular events and overall mortality in patients > 40 years old with secundum ASDs. This superiority was related to the mean pulmonary artery pressure, age at diagnosis and cardiac index. Because of the higher risk of morbidity and mortality, we believe that anatomic closure should always be attempted as the initial treatment for ASDs in adults > 40 years old with pulmonary artery systolic pressure < 70 mm Hg and a pulmonary/systemic output ratio > or =1.7. The operation must be performed as soon as possible, even if the symptoms or the hemodynamic impact seems to be minimal.

Adult↗
PubMed1999

The syndrome of pericarditis, arthritis, and camptodactyly: an under-recognized cause of pericardial constriction in children?

The syndrome encompassing the combination of pericarditis, arthritis, and camptodactyly is a rarely described cause of pericardial constriction in children. It is likely that this association is being under-recognized. We report a new case in which the skeletal abnormalities were subtle. The syndrome should be included in the differential diagnosis of any child with persistent non-inflammatory pericardial effusion. A careful search at the bedside for the associated skeletal abnormalities should lead to the correct diagnosis. Pericardiectomy is the treatment of choice.

Arthritis↗
PubMed1993

Primary hypertrophic osteoarthropathy: another heritable disorder associated with patent ductus arteriosus.

Patent ductus arteriosus (PDA) is a congenital malformation that has been linked to diverse heritable and chromosomal disorders. Primary hypertrophic osteoarthropathy (HOA) is a rare heritable syndrome in which digital clubbing and periostosis become evident without any underlying illness. The objective of this article is to describe four patients with coexisting PDA and primary HOA. Surgical closure of the ductus showed no effect on the skeletal changes. Primary HOA should be included among the heritable disorders that may be associated with PDA.

Child↗
PubMedDate not supplied

[Fenestrated Fontan surgery in high risk patients].

A retrospective analysis is presented of all patients who had fenestrated Fontan procedure between january 1990 and may 1996. Surgery was indicated in the presence of anyone of the following risk factors: mean pulmonary pressure higher than 20 mmHg; pulmonary vascular resistance higher than 2 UW; ejection fraction less than 60%; systemic ventricular end diastolic pressure higher than 8 mmHg; Nakata index less than 200 mm2/m2, McGoon index less than 2. The diagnosis were: Absent right atrio-ventricular connection with concordance ventriculo-arterial connection 10 patients; pulmonary atresia with intact septum, 1 patient; Ebstein's malformation, 1 patient and absent left A-V connection with discordance VA connection, 1 patient. The mean of age was 6.7 years (range 2.5-11 years). Overall mortality was 23%. No significant difference in risk factors was found between survivals and no survivals. Nonsurvivors had between two an four risks factors. Postoperative complications were 1 patient with protein losing enteropathy and stroke (1 patient). The mean duration of pleural effusion was 16 days (range 4-45 days). We consider fenestrated Fontan procedure useful for patients with congenital heart disease with a one hypoplastic ventricle and one o more risks factors.

Child↗
PubMedDate not supplied

Ebstein's anomaly. Clinical profile in 174 patients.

The study population consisted of 148 patients who did not undergo surgical treatment and 26 who were operated, most of them diagnosed after the age of 2, with a follow-up from 6 months to 25.3 years. Patients were divided in three groups of clinical deterioration according to their functional class and cardiothoracic index (CTR) long-term follow-up in 148 nonoperated patients showed significant differences for mortality between groups I and III (p < 0.001), and between groups II and III (p < 0.02). Predictors of death included the association among functional class III or IV CTR > or = 65% with either cyanosis or arrhythmias (p < 0.05). The multivariate analysis showed that clinical deterioration (p < 0.0001), CTR (p < 0.0002) and functional class (p < 0.001), were significant for mortality. Kaplan-Meier analysis showed a survival rate of 81% in the overall patients free from surgical treatment. According to Kaplan-Meier analysis, the rate of survival was lower in patients with CTR > or = 65% (63.5%), in patients who had functional class IV (52.5%) and in patients included in group III of clinical deterioration (38.2%). Despite the fact that the association of functional class III or IV plus CTR > or = 65% with either cyanosis or arrhythmias is a good predictor for death, the mortality in patients who had only one of these variables was lower. Patients included in group II of clinical deterioration in stable condition presented long survival with medical treatment. Due to the high mortality rate found in group III, surgical treatment of Ebstein's anomaly must be done before deteriorating into group III. Surgical indication must be done considering the surgical risk of each group according to the experience of the Institution and comparing the rate of surgical mortality with the rate of survival without surgery.

Adolescent↗
PubMedDate not supplied

Interventional cardiology in congenital heart disease.

Interventional procedures for congenital heart disease have evolved dramatically in the last decade. Beginning with pulmonary and aortic valvuloplasty, nowadays, stents and various devices are placed inside the heart and vessels to palliate or correct different congenital defects. The present communication summarizes the experience with interventional cardiology in congenital heart disease of the Instituto Nacional de Cardiología "Ignacio Chávez" during the last five years.

Adolescent↗
PubMedDate not supplied

[Permanent rhythm and conduction disorders in patients surgically treated for atrial septal defect].

Atrial septal defect (ASD) represents a congenital heart disease with good prognosis, however, atrial arrhythmias are well-documented complications. A retrospective study was performed to assess the prevalence, types and risk factors of arrhythmias in patients with ASD after surgical correction. 920 patients were analyzed retrospectively; cases with complex congenital heart disease or another systemic alteration conditioning atrial rhythm disturbances were excluded. 460 patients with ASD corrected by surgery were followed at least for six months after the procedure. 29.3% of patients were male and 70.7% female. Direct closure was performed in 63%, pericardial patch was installed in 27%. 29 patients (6.3%) had conduction and rhythm disturbances before surgery, the most common arrhythmias were atrial flutter (34.5%), first degree A-V block (31%) and low right atrial rhythm (27.6%). Six months after atrial defect closure, 65 patients (14.13%) had arrhythmias, 44.6% atrial flutter, 20% ectopic atrial rhythm, 10.8% sick sinus syndrome. The risk of atrial arrhythmias was related to age at surgical repair, pulmonary hypertension and atrial arrhythmias before surgery.

Adult↗
PubMedDate not supplied

[Late results of mitral valve replacement in 155 subjects under 16 years of age. Comparative study with 4 prosthesis].

We followed 155 children aged 6 to 16 years who underwent mitral valve replacement for rheumatic heart disease. Group I included 74 patients with Starr-Edwards prostheses and the mean follow-up period was 13 years. Group II was formed by 36 patients with Bjork-Shiley prostheses and a mean follow-up of 7.5 years. Group III consisted of 31 children with dura mater bioprostheses and a mean follow-up of 5.1 years. Finally, group IV included 14 patients followed a mean period of 4.9 years with Hancock xenografts. The four groups of patients were comparable before surgery. The criteria of the New York Heart Association (NYHA) were used to evaluate all patients before and 12 months after surgery. All patients with mechanical prostheses received anticoagulant therapy with acenocumarol from the first postoperative day. The incidence of complications such as thromboembolism, infective endocarditis, prosthetic dysfunction and death were determined at the end of the follow-up. The Fisher's exact test was used for nonparametric analysis and the two-tailed Student's T test for parametric results. All but two patients improved their NYHA clinical status after surgery (p less than 0.0001). Forty eight patients with mechanical prostheses were catheterized 1 to 7 years after the operation. The mean pulmonary arterial systolic pressure was reduced from 58 mmHg to 30 mmHg (p less than 0.001) and the mean pulmonary arterial wedge pressure decreased from 22 mmHg to 11 mmHg (p less than 0.001). There were no significant differences between the groups with mechanical and tissue prostheses in the incidence of thromboembolism and infective endocarditis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

[Primary pulmonary arterial hypertension in children under 2 years of age].

A retrospective analysis of 18 patients under two years of age who suffered from primary pulmonary hypertension was made between july 1982 november 1988 in order to define their clinical course and prognosis. Perinatal history was irrelevant. In 13 patients diagnosis was established before the first year of life and in 8 of them in the neonatal period. All patients presented the same symptomatology: Cyanosis, dyspnea and/or repeated respiratory infections. The electrocardiogram showed various degrees of enlargement of the right atrium and right ventricle as well as an uneven ST segment in the precordial leads; these could not be related to the systolic or diastolic pressures of the right ventricle. In the chest roentgenogram the most important and constant feature was the heart enlargement. Cardiac catheterization showed a mean pulmonary systolic arterial pressure of 64.46 mmHg and a mean pulmonary arterial resistance of 6.4 U/m.2 These parameters could not be related to a bad prognosis. Three patients were given vasodilators (hydralazine) with positive clinical and echocardiographic results. Five patients died (27%) two months after the diagnosis was made and three months after the onset of symptomatology, four of them died due to congestive heart failure and one had sudden death. This study shows the early onset of the disease as well as its short term high mortality.

Age Factors↗
PubMedDate not supplied

[Comparative study of 2 mechanical mitral valves].

We present the long term follow-up of two groups of patients under 16 years of age in whom two different types of mitral valve prostheses were used for the treatment of mitral valve disease. Group I was formed by 74 patients with Starr-Edwards (6120) prosthesis and group II by 36 cases with Bjork-Shiley prosthesis. Group I was followed for a mean period of 11 years and group II for a mean period of 7.5 years. The clinical evolution of both groups assessed according to the New York Heart Association criteria showed improvement of the functional class (p less than 0.006). Twenty seven cases of group I and 21 of group II underwent cardiac catheterization for the evaluation of surgical results. In group I, the mean pulmonary arterial systolic pressure (PASP) decreased from 57 mmHg to 33 mmHg (p less than 0.001) and the mean pulmonary arterial wedge pressure (PAWP) from 20.8 mmHg to 12.1 mmHg (p less than 0.05). In group II, the mean PASP decreased from 59.2 mmHg to 28.5 mmHg (p less than 0.001) and the mean PAWP from 24.6 mmHg to 8.5 mmHg (p less than 0.001). There was statistically significant difference for a greater incidence of thromboembolism in group I (p = 0.037). No differences were found for bacterial endocarditis, dysfunction and death.

Adolescent↗
PubMedDate not supplied

[Surgical alternatives in the treatment of double-outlet right ventricle].

Double-outlet right ventricle (DORV) is a type of ventriculo-arterial connection, in which both great arteries are connected to the morphologically right ventricle in at least 50% of their diameter. The relation of the great arteries with the ventricular septal defect (VSD) and the pulmonary stenosis, are important anatomical aspects in the election of the surgical technique. In this study we describe four patients with DORV, in whom different surgical techniques were used according to the specific anatomy of each case. Two patients had subaortic restrictive VSD, with subpulmonary stenosis in one of them. In the other two patients the VSD was subpulmonary with the aorta anterior and to the left, in one of these existed moreover a severe mixed pulmonary stenosis. It is concluded, that with different surgical techniques according to the specific anatomy of each patient, good results can be obtained in the surgical treatment of these complex congenital malformations.

Child↗
PubMedDate not supplied

[Tetralogy of Fallot with abnormal coronary arteries].

Between 1980 and 1989 nine patients with Tetralogy of Fallot with abnormal coronary artery underwent surgical treatment. In all but one, the abnormal coronary artery was identified at surgery. Seven (group I) had the anterior descending coronary artery arising from the right coronary artery; one (group II) with had the right coronary artery arising from the left coronary artery and finally, the only case of the group III had left coronary artery arising from the main pulmonary artery. Systemic-pulmonary anastomosis was done in two cases of the Group I, in one due to severe hypoplasia of the pulmonary ring and main pulmonary artery and in the other due to the anomaly of the coronary artery. In the case of the Group II the right coronary artery was accidentally cut and the patient developed right ventricular infarction and died. All surviving are in NYHA functional class I. Nowadays, the preoperative evaluation of Tetralogy of Fallot, can be done by echocardiography despite the possibility of its association with abnormal coronary artery. In special cases aortography or arterial coronarography should be considered.

Anastomosis, Surgical↗
PubMedDate not supplied

[Discordance in the anatomy of the bronchial tree and atrial appendages].

It is well known, that in complex congenital heart disease, the bronchial anatomy reflects the atrial situs in the majority of patients. Few exceptions to this rule have been reported in the literature. We report four patients in whom we found discordance between the anatomy of the bronchial tree and the external aspect of the atrial appendages. Two patients had bronchial situs solitus with atrial levoisomerism, the third patient had bronchial levoisomerism with atrial situs solitus and in the fourth one we found inverted bronchial anatomy with levoisomerism of the atrial appendages. In three patients, broncho-atrial discordance was diagnosed clinically by bronchial tomography and selective atrial angiography, and in the other one the diagnosis was made by anatomical study. In this last patient, external atrial anatomy was found to be of levoisomerism, with an internal atrial aspect of situs inversus. Prediction of atrial arrangement by bronchial anatomy retains its diagnostic value. However, it is necessary to bear in mind that exceptions do exist. It is discussed how to suspect these exceptions, and the final diagnostic conduct is indicated.

Bronchi↗
PubMedDate not supplied

[Congenital ventricular diverticula. Presentation of 6 cases].

Congenital diverticulum of the heart is an unusual malformation. It is frequently associated with thoracic or abdominal midline alterations and also with various types of congenital heart disease. Complications of this anomaly are rupture, peripheral embolism and heart failure. Surgical management consists of resection of the diverticulum either as an isolated operation or at the time of correction of accompanying malformations. We present six cases of congenital diverticulum of the heart, four on the right ventricle and two on the left. In one patient with Fallot's tetralogy a diverticulum was found at necropsy; in two cases the underlying malformation was double outlet ventricle; one case had pulmonary artery stenosis and two did not have associated malformations.

Child↗