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Biomedical subjects

C Duran

Publications and source records attributed to C Duran.

At least 19 recordsLinked to original sources
PubMed2006

Speciation of Cr(III) and Cr(VI) after column solid phase extraction on Amberlite XAD-2010.

A speciation procedure for Cr(III) and Cr(VI) based on column solid phase extraction on Amberlite XAD-2010 and flame atomic absorption spectrometry combination. Cr(VI) was quantitatively recovered on Amberlite XAD-2010 resin at pH range of 2.0-3.0 as its diethyldithiocarbamate complex, while the recoveries of Cr(III) was below 5%. The influences of the various parameters including amounts of the reagents, eluent type and its volume, sample volume, etc., on the quantitative recoveries were examined. The interference of matrix and coexistent elements for method were studied. The detection limit (corresponding to three times the standard deviation of the blank) and the enrichment factor for Cr(VI) were found to be 1.28 microg/L and 25, respectively. To verify the accuracy of the method, drinking water certified reference material (CRM-TMDW-500) was analyzed and the results obtained were in good agreement with the certified value. The proposed method has been successfully applied to the speciation of Cr(III) and Cr(VI) in water samples and preconcentration of total chromium in environmental samples.

Chromium↗
PubMed2006

[The left ventricular reconstructive surgery at the origin of the treatment of cardiac insufficiency].

The surgical method of ventricular reconstruction described by Dor is recalled with the clinical report of a patient who presented a ventricular aneurysm. The left ventricular reconstructive surgery is based on an anatomical design of the heart described by Torrent-Guasp, where the normal orientation of the left ventricular muscle fibers, oblique in direction, is found parallel with the base of the heart at the time of ventricular dilation. By giving again an elliptic form to the left ventricle, the left ventricular reconstructive surgery improves the cardiac function of the patient who developed a bulky aneurysm after an infarction. Based on this concept, other techniques of ventricular reconstruction intended for patients presenting dilated cardiomyopathy, of ischemic origin or not, are being studied.

Cardiac Surgical Procedures↗
PubMed2005

[Cardiac surgery after liver transplantation].

An aortic valve replacement and an aorto-coronary bypass were done in a woman of 57 years old after an orthotopic liver transplantation. The surgical risk was increased by the antecedent liver transplantation, the immunosuppression, chronic renal insufficiency and antiphospholipid syndrome. Surgery and the post-operative period were not complicated. Cardiac surgery is not a contraindication for patients with a prior organ transplant. These individuals have a higher cardiovascular risk and require a cardiovascular follow-up the modalities of which are yet to be defined.

Antiphospholipid Syndrome↗
PubMed2002

Monostotic fibrous dysplasia of the clivus: MRI and CT findings.

Fibrous dysplasia is a developmental disorder caused by abnormal proliferation and maturation of fibroblasts resulting in replacement of mature bone by structurally weak, immature woven bone. Clival involvement in monostotic fibrous dysplasia is extremely unusual, and has rarely been reported previously. We report a case of monostotic fibrous dysplasia of the clivus with special emphasis on the imaging findings and differential diagnosis.

Adult↗
PubMed2002

Macrolide resistance phenotypes in Streptococcus pneumoniae in Santiago, Chile.

The mechanism of resistance was investigated in 39 macrolide-resistant clinical isolates of Streptococcus pneumoniae isolated from January 1997 to July 1999 in Santiago, Chile. Our results showed that 22 (56.5%) were macrolide-resistant, clindamycin-susceptible isolates (M phenotype) and 17 (43.5%) were macrolide and clindamycin resistant (MLS(B) phenotype). mefE gene was detected in all M phenotype, while ermB gene was detected in all MLS(B)-phenotype strains. Serotype 14 was the most frequent serotype among M-phenotype strains, and serotypes 19 and 23F were the most frequent serotypes in MLS(B) strains. These results demonstrate that both phenotypes of macrolide-resistant S. pneumoniae are found in Santiago, Chile, with the M phenotype predominating.

Adult↗
PubMed2002

Molecular analysis of HLA-DRB1, DQA1, DQB1, DQ promoter polymorphism and extended class I/class II haplotypes in the Seri Indians from Northwest Mexico.

The study of the genetics of the Major Histocompatibility Complex (MHC) in Amerindians is of great value in understanding the origins and migrations of these native groups, as well as the impact of immunogenetics on the epidemiology of diseases affecting these populations. We analyzed, using Polymerase Chain Reaction and Sequence Specific Oligonucleotide Probes (PCR-SSOP), DRB1, DQA1, DQB1 alleles and the promoter regions of DQA1 and DQB1 genes in 31 unrelated and 24 related Seri, a Mexican Indian group, from the state of Sonora (Northwest Mexico). The class II genotypes of this population were found to be in genetic equilibrium. The allele frequency (AF) of the prevalent DRB1 alleles were DRB1*0407 (48.4%), DRB1*0802 (33.9%) and DRB1*1402 (16.1%). The most frequent DQA1 and DQB1 alleles were DQA1*03011 (AF = 50.00%), DQA1*0401 (AF = 33.87%) and DQA1*0501 (AF = 16.13%); DQB1*0302 (AF = 50.00%), DQB1*0402 (33.87%) and DQB1*0301 (16.13%); which were in combination with DRB1*0407, DRB1*0802 and DRB1*1402, respectively. Three QAP and three QBP alleles were present (QAP 3.1, 4.1, 4.2; QBP 3.1, 3.21, 4.1) associated with the typical published DQA1 and DQB1 alleles. Four class II haplotypes were present in family members: DRB1*0407-QAP-3.1-DQA1*03011-QBP-3.21-DQB1*0302; DRB1*0802-QAP-4.2-DQA1*0401-QBP-4.1-DQB1*0402; DRB1*1402-QAP-4.1-DQA1*0501-QBP-3.1-DQB1*0301 and DRB1*0701-QAP-2.1-DQA1*0201-QBP-2.1-DQB1*0201. The family data were used to confirm extended haplotypes. A total of 21 haplotypes were found when A* and B* loci were also considered. The three most frequent combinations included A*0201-B*3501-DRB1*0407, A*3101-B*5101-DRB1*0802, and A*0201-B*40-DRB1*1402.

Emigration and Immigration↗
PubMed2002

Distribution of TAP gene polymorphisms and extended MHC haplotypes in Mexican Mestizos and in Seri Indians from northwest Mexico.

The study of the genetic structure is very useful for investigating the biological significance of polymorphism and may provide clues to understand population origins. We present TAP1/TAP2 gene analysis in the Seri indians from Sonora, and in Mestizos from the highlands of Mexico. Thirty-two Seri and 89 Mestizos were studied. TAP genes were typed using the ARMS-PCR technique. The most frequent alleles in Seri were: TAP1*0101/02, (68.8%); TAP1*02011/02012, (31.2%); TAP2*0201, (38.7%) and TAP2*0101, (29.0%). TAP1*0301, TAP1*0401, TAP2*0102 TAP2*0103 and TAP2H were absent in them. For Mestizos, the prevalent alleles were: TAP1*0101/02 (75.8%); TAP1*02011/12 (20.3%); TAP2*0101 (45.4%) and TAP2*0201 (29.3%). These results are similar to those found in Kaingang and Caucasians from Brazil, four Mediterranean, other Caucasians, two Oriental and one African group. In Seri, the extended prevalent haplotypes are typically Amerindian, such as TAP1*0101/2-TAP2*0201-QBP3.21-DQB1*0302-QAP*3.1-DQA1*03011-DRB1*0407-B*3501-A*0201 (HF = 16.6%). Thirty-two extended haplotypes were found in Seri, although TAP contributed scarcely to diversity. Mestizos show Amerindian and Caucasian combinations. No difference was detected in the distribution of amino acids in the individual variable sites, between both groups. These findings are the basis for further anthropological studies and to explore the contribution of TAP genes to disease expression in Mexicans.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

Hybrids of pluripotent and nullipotent human embryonal carcinoma cells: partial retention of a pluripotent phenotype.

To investigate whether the failure of human EC cells that do not differentiate is due to the loss of key differentiation-permissive functions or the acquisition of specific inhibitory functions, we tested the ability to differentiate of 2 hybrids produced between a relatively nullipotent human EC cell line, 2102Ep, and a pluripotent human EC cell line NTERA2. Both hybrids, which exhibited an EC phenotype, were able to differentiate readily in response to retinoic acid. Furthermore, 1 hybrid produced a well-differentiated xenograft tumor, which contained, like the NTERA2 tumors, glandular structures, loose mesenchymal tissues and nodules of cartilage, after injection into a SCID mouse. Thus, the failure of 2102Ep EC cells to differentiate is recessive and due to the loss of a key gene function or functions. Nevertheless, the hybrids differed from the pluripotent NTERA2 line by failing to differentiate in neurons, indicating that 2102Ep cells also had acquired a specific, dominantly-acting, inhibitory mutation specific to the neural lineage. Furthermore, the expression of collagen II by one hybrid before and after induction with retinoic suggested a propensity for spontaneous differentiation not evident in the parental NTERA2 cells. Thus, the mechanisms that restrict the differentiation capacity of the nullipotent 2102Ep line are complex and include both recessive and dominant acting factors.

Animals↗
PubMed2001

Spontaneous retroperitoneal hemorrhage secondary to subcapsular renal hematoma: MRI findings.

Spontaneous retroperitoneal hemorrhage is a rare intraabdominal bleeding. In this report we present a case of a nontraumatic retroperitoneal hemorrhage secondary to spontaneous subcapsular renal hematoma. A 54-year-old patient who was under warfarin therapy, developed subcapsular right renal hematoma. Subcapsular and retroperitoneal hemorrhage were low signal on T1- and T2-weighted images consistent with acute stage of blood. The source of subcapsular hematoma was shown to be the rupture of hemorrhagic renal cyst on MRI. Extension of hemorrhage into the retroperitoneal space anterior to right psoas muscle was also successfully shown on MRI. Patient underwent nephrectomy and retroperitoneal blood was evacuated.

Hematoma↗
PubMed2001

Repair of moderate aortic valve lesions associated with other pathology: an 11-year follow-up.

OBJECTIVES: The presence of moderate aortic valve (AV) lesions associated with other pathologies that require surgery presents a problem since ignoring or replacing the valve seems unsatisfactory. AV repair can be an attractive alternative if shown to perform satisfactory. METHODS: To evaluate this possibility, all consecutive AV patients who underwent operation between July 1988 and July 1999 were reviewed. Out of 1764 AV patients, 239 (14%) underwent repair and 86 (study group) had moderate lesions associated with mitral (73), tricuspid (33), coronary disease (5) and others (8). Mean age was 28 years (range 2--66); 78% were rheumatic, 71% were in sinus rhythm and 71% in NYHA class III--IV. RESULTS: There were seven hospital deaths (8%) and three patients were lost to follow-up (95% complete). Late mortality was 8% and 10-year actuarial survival was 86 +/- 4.5% (excluding hospital mortality). There were four (5%) embolic events (actuarial freedom 94 +/- 3.5%). Twenty-one patients required reoperation with two mortalities. The AV was not touched in five patients. In the remaining 16, the AV was replaced. Only one patient had isolated AV replacement while in all others, additionally, the mitral, tricuspid, or both required surgery. All reoperated patients had rheumatic etiology. Actuarial freedom from AV dysfunction at 8 years was 68 +/- 7.5%. CONCLUSIONS: Repair of associated moderate AV lesion is worth considering even in a predominantly young rheumatic population.

Adolescent↗
PubMed1999

The expression and function of cadherin-mediated cell-to-cell adhesion in human embryonal carcinoma cells.

Human embryonal carcinoma (EC) cells typically require high cell densities to maintain their characteristic phenotype; they are generally subject to differentiation when cultured at low cell densities, marked by changes in morphology and expression of the surface antigen, SSEA-1. To test whether cadherin mediated cell-to-cell adhesion may be responsible for maintaining an EC phenotype we ascertained that human EC cells generally express E- and P-cadherins, and are subject to cadherin mediated, Ca2+ dependent aggregation. However, in the NTERA2 human EC cell line, inhibition of cadherin mediated adhesion by culture in low levels of Ca2+ did not result in the changes typically seen under low cell density conditions. Low Ca2+ levels also did not affect the pattern of differentiation in these cells following induction with retinoic acid. Therefore, cadherin-mediated cell adhesion does not appear to play a role in maintaining an EC phenotype. On the other hand, culture at both low cell density and in the absence of Ca2+ did result in changes in the patterns of cadherin expression suggesting a feedback regulatory effect of cell-to-cell adhesion. Further, lithium which inhibits the cytoplasmic kinase GSK3beta and hence influences beta-catenin levels did cause differentiation of NTERA2 cells. However, consideration of the phenotype of the resultant cells suggested that this effect may be because of lithium mimicking activation of a Wnt signalling pathway, rather than an effect on signalling consequent upon cadherin mediated cell to cell adhesion.

Cadherins↗
PubMed1998

Spontaneous involution of pulmonary sequestration in children: a report of two cases and review of the literature.

BACKGROUND: Two cases of pulmonary sequestration which regressed spontaneously are presented. OBJECTIVE: To demonstrate the value of imaging studies in the diagnosis and follow-up of some forms of congenital masses of the lung in asymptomatic patients. MATERIAL AND METHODS: We reviewed the clinical records and imaging studies of two asymptomatic children, one newborn and the other 3 months old, with thoracic masses which demonstrated variable degrees of spontaneous involution. RESULTS: Abdominal ultrasound performed on the newborn with a palpable mass showed a triangular echogenic mass with a large central feeding vessel arising from the aorta. The mass had disappeared on follow-up US exam performed 6 years later. CT was performed in the 3-month-old patient with a persistent retrocardiac mass. A soft-tissue density mass in the left pulmonary base with a large feeding vessel arising from the aorta was visualised on contrast-enhanced CT. Five years later, a new CT scan showed significant shrinkage of the mass and no vessel. CONCLUSION: Radiological techniques such as real-time US with Doppler imaging and contrast-enhanced CT may establish the diagnosis of pulmonary sequestration by demonstrating the mass and its systemic vessel, thereby eliminating the need for more aggressive imaging procedures. Partial or total disappearance of these masses represents a further example of involutive pathology and suggests that not all cases of pulmonary sequestration should be surgically treated.

Bronchopulmonary Sequestration↗
PubMed1996

Advantage of Inoue balloon catheter in mitral balloon valvotomy: experience with 220 consecutive patients.

Percutaneous mitral balloon valvotomy (PMV) using the Inoue balloon catheter was attempted in 220 consecutive patients with severe symptomatic mitral stenosis. Their age range was 10-63 mean 30 +/- 10 years; 161 patients were females and 59 were males; 29 patients were in atrial fibrillation. Eleven patients were pregnant; 14 patients underwent previous surgical commissurotomy. The procedure was technically successfully performed in 215 (97.7%) patients. The mean fluoroscopy time was 15.5 +/- 6.4 min and mean procedure time was 109 +/- 79 min. Optimal results (group I) was achieved in 207 patients who have mitral score of 7 +/- 1. PMV resulted in decrease in left atrial pressure from 23 +/- 5 to 14 +/- 4 mm Hg (P < 0.001), the mean mitral valve gradient (MVG) decreased from 15 +/- 4 to 6 +/- 3 mm Hg (P < 0.001). The mitral valve area (MVA) by catheter increased from 0.7 +/- 0.2 to 1.7 +/- 0.5 cm2 (P < 0.001) and MVA as determined by echocardiography (2DE) increased from 0.8 +/- 0.1 to 1.9 +/- 0.3 cm2 (P < 0.001). The results were suboptimal in eight patients who have a mitral score of 10 +/- 1 (group II) MVA by catheter increased from 0.7 +/- 0.2 to 1 +/- 0.1 cm2 and Doppler MVA increased from 0.8 +/- 0.1 to 1.3 +/- 0.1 cm2. There were no deaths or thromboembolism. Two patients developed cardiac tamponade; mild mitral regurgitation (MR) developed in 24 patients (11%) and increased by one grade in another 22 patients (10%). Severe MR was encountered in three patients (1.4%). A small ASD (QP/QS < or = 1.3) was detected by oximetry in 5% of patients and by color-flow mapping in 26% of patients. One hundred fifty-eight patients from group I were followed up, for a mean of 32 +/- 12 months; MVA remained at 1.7 +/- 0.4 cm2. Seven patients developed mitral restenosis in group I, and 5 out of 8 patients developed restenosis in group II. We conclude that the hemodynamic results are good and comparable with those reported with double balloon technique. However, the Inoue balloon has several advantages over the double balloon technique: (1) low incidence of mitral regurgitation and ASDs; (2) shorter procedure and fluoroscopy time; and (3) low complication rates and the valve anatomy affects the immediate and late outcome of mitral balloon valvotomy.

Adolescent↗