RESUMEN

Metal-reducing bacteria in the genus Geobacter use a complex protein apparatus to guide the self-assembly of a divergent type IVa pilin peptide and synthesize conductive pilus appendages that show promise for the sustainable manufacturing of protein nanowires. The preferential helical conformation of the Geobacter pilin, its high hydrophobicity, and precise distribution of charged and aromatic amino acids are critical for biological self-assembly and conductivity. We applied this knowledge to synthesize via recombinant methods truncated pilin peptides for the bottom-up fabrication of protein nanowires and identified rate-limiting steps of pilin nucleation and fiber elongation that control assembly efficiency and nanowire length, respectively. The synthetic fibers retained the biochemical and electronic properties of the native pili even under chemical fixation, a critical consideration for integration of the nanowires into electronic devices. The implications of these results for the design and mass production of customized protein nanowires for diverse applications are discussed.IMPORTANCE The discovery in 2005 of conductive protein appendages (pili) in the metal-reducing bacterium Geobacter sulfurreducens challenged our understanding of biological electron transfer and pioneered studies in electromicrobiology that revealed the electronic basis of many microbial metabolisms and interactions. The protein nature of the pili afforded opportunities for engineering novel conductive peptides for the synthesis of nanowires via cost-effective and scalable manufacturing approaches. However, methods did not exist for efficient production, purification, and in vitro assembly of pilins into nanowires. Here we describe platforms for high-yield recombinant synthesis of Geobacter pilin derivatives and their assembly as protein nanowires with biochemical and electronic properties rivaling those of the native pili. The bottom-up fabrication of protein nanowires exclusively from pilin building blocks confirms unequivocally the charge transport capacity of the peptide assembly and establishes the intellectual foundation needed to manufacture pilin-based nanowires in bioelectronics and other applications.

Asunto(s)

Proteínas Fimbrias/metabolismo , Geobacter/metabolismo , Péptidos/metabolismo , Aminoácidos Aromáticos/metabolismo , Conductividad Eléctrica , Transporte de Electrón/fisiología , Fimbrias Bacterianas/metabolismo , Nanocables

RESUMEN

Geobacter sulfurreducens (GS) electronically connects with extracellular electron acceptors using conductive protein filaments or pili. To gain insights into their role as biological nanowires, we investigated the structural dynamics of the GS pilus in solution via molecular dynamics simulations. In the model, all of the pilin's aromatics clustered as a right-handed helical band along the pilus, maintaining inter-aromatic distances and dimer configurations optimal for multistep hopping. The aromatics were interspersed within the regions of highest negative potential, which influenced the type and configuration of the aromatic contacts and the rates of electron transfer. Small foci of positive potential were also present but were neutralized within uncharged regions, thus minimizing charge trapping. Consistent with the model predictions, mutant strains with reduced aromatic contacts or negative potentials had defects in pili functions such as the reduction of Fe(III) oxides and electrodes. The results therefore support the notion of a pilus fiber evolved to function as an electronic conduit between the cell and extracellular electron acceptors.

Asunto(s)

Conductividad Eléctrica , Fimbrias Bacterianas/química , Fimbrias Bacterianas/metabolismo , Geobacter/citología , Simulación de Dinámica Molecular , Aminoácidos/química , Aminoácidos/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Transporte de Electrón , Conformación Proteica , Electricidad Estática

RESUMEN

Four boar ejaculates were preserved for 42d at 15 degrees C to examine the changes produced in the quality of sperm membranes according to their response to a combined short hypoosmotic swelling test (sHOST) plus viability test designated the sHV test. Every 1 or 2d, a sample from each ejaculate preserved in long-term extender was subjected to sperm motility determination and the sHV test. Through simultaneous examination by phase contrast and fluorescence microscopy, three subpopulations of sperm were identified according to their response to sHOST challenge and their viability status. In the subpopulations scoring positive in the sHOST, a further four sperm subpopulations were defined according to their viability and acrosome status. All the sperm subpopulations differed in terms of changes in their proportions produced during the course of preservation and individual differences among ejaculates were detected in terms of relationships shown among subpopulations. The combined sHOST/viability test was able to identify sperm subpopulations with the strongest plasma and acrosome membranes as well as a subpopulation of sperm that had undergone a true acrosome reaction.

Asunto(s)

Membrana Celular/fisiología , Preservación de Semen/veterinaria , Espermatozoides/citología , Espermatozoides/fisiología , Animales , Criopreservación/veterinaria , Congelación , Masculino , Porcinos , Factores de Tiempo

RESUMEN

Species of strictly and facultatively anaerobic cellulolytic bacteria from soils and sediments were examined for the ability to degrade chitin. Of 22 species studied, 16 degraded insoluble chitin. Cellulomonas uda, which was selected for a comparative study of its cellulase and chitinase enzyme systems, produced different enzyme systems for the degradation of cellulose and chitin and different patterns of regulation of production of the two enzyme systems were observed. Moreover, C. uda utilized chitin as a source of nitrogen for the degradation of cellulose. In natural environments, the ability to use chitin as a nitrogen source may confer on cellulolytic microorganisms, such as C. uda, a selective advantage over other cellulolytic microbes.

Asunto(s)

Actinomycetales/metabolismo , Bacterias Anaerobias/metabolismo , Celulosa/metabolismo , Quitina/metabolismo , Sedimentos Geológicos/microbiología , Microbiología del Suelo , Actinomycetales/crecimiento & desarrollo , Aerobiosis , Bacterias Anaerobias/crecimiento & desarrollo , Celulasa/metabolismo , Quitinasas/metabolismo

RESUMEN

UNLABELLED: In this clinical study, 7 pediatric patients with severe pulmonary artery hypertension, secondary to congenital heart disease, received inhaled nitric oxide at doses of 20 ppm in the acute postoperative management of congenital heart repair for 3.5 days. Monitoring included oxygenation index, alveoloarterial oxygen difference, pulmonary and systemic pressure, measurements were recorded previous to the NO administration; 1, 6, 12, 24, 36, 48 and 72 hours after treatment with NO, nitrous oxide (NO2) and seric methemoglobin also were monitored. RESULTS: Average age was 3.6 years. The oxygenation index before inhaling NO was 166 +/- 100, 72 hours following inhalation of NO the oxygenation index was 210 +/- 98. The alveolo-arterial baseline oxygen difference was 270 +/- 145; 72 hours after inhaling NO, it was 163 +/- 167. No decreases in pulmonary and systemic arterial pressure during NO inhalation occured. The levels of NO2 and seric methemoglobin were not toxic. CONCLUSIONS: Treatment with inhaled NO after cardiac surgery in children with severe pulmonary artery hypertension secondary to congenital heart disease may be useful to improve oxygenation with no changes in pulmonary and systemic arterial pressure. Inhaled NO at 20 ppm did not cause toxicity.

Asunto(s)

Cardiopatías Congénitas/complicaciones , Cardiopatías Congénitas/cirugía , Hipertensión Pulmonar/etiología , Óxido Nítrico/farmacología , Consumo de Oxígeno/efectos de los fármacos , Adolescente , Niño , Estudios Transversales , Femenino , Cardiopatías Congénitas/metabolismo , Humanos , Hipertensión Pulmonar/metabolismo , Lactante , Recién Nacido , Masculino , Periodo Posoperatorio , Estudios Retrospectivos , Índice de Severidad de la Enfermedad

RESUMEN

Sixty out of 219 fosfomycin-resistant bacteria selected from more than 7400 urinary pathogens in an epidemiological multicentre survey performed in Italy were screened for plasmid genes fosA and fosB conferring fosfomycin resistance. Only five strains, three enterobacteria and two staphylococci, carried plasmids harbouring, respectively, fosA and fosB genes. Fosfomycin resistance in the other isolates was caused by an alteration of the chromosomally encoded GlpT transport system. One strain, Morganella morganii 279, incorporated alpha-glycerolphosphate and its mechanism of fosfomycin resistance needs to be further investigated. Our study showed that PCR amplification is the most accurate, simple and rapid method for epidemiological studies of plasmid-encoded fosfomycin resistance, and that fosfomycin resistance conferred by plasmid genes (both fosA and fosB) accounts for only a low percentage of the fosfomycin-resistant strains.

Asunto(s)

Fosfomicina/farmacología , Genes Bacterianos , Bacterias Gramnegativas/genética , Bacterias Grampositivas/genética , Plásmidos/genética , Sistema Urinario/microbiología , Transferasas Alquil y Aril/metabolismo , ADN Bacteriano/genética , Farmacorresistencia Microbiana/genética , Activación Enzimática , Amplificación de Genes , Glucosa-6-Fosfato/metabolismo , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Gramnegativas/enzimología , Bacterias Gramnegativas/metabolismo , Bacterias Grampositivas/efectos de los fármacos , Bacterias Grampositivas/enzimología , Bacterias Grampositivas/metabolismo , Humanos , Técnicas In Vitro , Italia , Cinética , Pruebas de Sensibilidad Microbiana , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Reacción en Cadena de la Polimerasa , Análisis de Secuencia de ADN

RESUMEN

There are numerous reports concerning left ventricular rupture after mitral valve replacement, and it has been classified according to location, treatment and prognosis. A somewhat less terrific complication has appeared as modifications have been introduced to the surgical technique, decreasing the frequency of rupture, but otherwise increasing the frequency of incomplete laceration, which has seldom appeared in literature. We review the case of a patient with incomplete left ventricular laceration after mitral valve replacement.

Asunto(s)

Rotura Cardíaca/etiología , Prótesis Valvulares Cardíacas/efectos adversos , Ventrículos Cardíacos , Estenosis de la Válvula Mitral/cirugía , Femenino , Humanos , Persona de Mediana Edad , Válvula Mitral

Asunto(s)

Humanos , Femenino , Embarazo , Adolescente , Adulto , Colecistectomía/estadística & datos numéricos , Colelitiasis/epidemiología , Colelitiasis/complicaciones , Incidencia , Prevalencia , Salud de la Mujer , Obesidad/complicaciones , Distribución de Chi-Cuadrado

RESUMEN

The long-term follow-up of patients with bioprosthetic valves manufactured at the Instituto Nacional de Cardiología Ignacio Chávez is presented. From February 1983 to May 1990, 1068 patients were operated and 1252 valves were replaced. Eighty two percent had rheumatic heart disease with one or more injured valves. In 17% it was a replacement of a failing valve. Seventy three percent of the patients had a low or medium-low socioeconomical status. There were 176 perioperative deaths in the first month after the operation and 150 patients were lost to follow-up. The rest (740) are the subject of this report. Mortality associated with valve related complications had a probability of 0.74 +/- 0.05, it had a significative increase after month 70th, with a 88% survival at that time. The functional class in the whole group improved 90%, with confidence limits for binomial distribution between 85 and 97%. There was also a significant reduction in heart enlargement. There were 161 prosthesis dysfunctions due to valve calcification or rupture, 50 were replaced. Twenty-three patients had hemolysis, and 19 infective endocarditis. There were 6.5% with systemic embolism in spite that only one half of those in which there was an indication, different of the valve replacement, received anticoagulant medication. The use of this prosthesis is on economical and medical satisfactory solution for the problem of a great number of our population of patients.

Asunto(s)

Bioprótesis , Prótesis Valvulares Cardíacas , Academias e Institutos , Adolescente , Adulto , Anciano , Válvula Aórtica , Bioprótesis/efectos adversos , Bioprótesis/estadística & datos numéricos , Cardiología , Niño , Preescolar , Femenino , Estudios de Seguimiento , Enfermedades de las Válvulas Cardíacas/epidemiología , Enfermedades de las Válvulas Cardíacas/mortalidad , Enfermedades de las Válvulas Cardíacas/cirugía , Prótesis Valvulares Cardíacas/efectos adversos , Prótesis Valvulares Cardíacas/mortalidad , Prótesis Valvulares Cardíacas/estadística & datos numéricos , Humanos , Masculino , México/epidemiología , Persona de Mediana Edad , Válvula Mitral , Diseño de Prótesis , Falla de Prótesis , Válvula Tricúspide

RESUMEN

In order to know the post-operative outcome of patients with valvular replacement due to prosthetic dysfunction, we reviewed the clinical charts of 94 patients operated at the Instituto Nacional de Cardiología "Ignacio Chávez" between January 1986 and December 1988. Eighty four cases were replaced by the first time the remaining 10 by a second time. Diagnosis of prosthetic dysfunction was made by clinical, radiological, echocardiographic and haemodynamic parameters. The most frequent causes of dysfunction were the rupture of prosthetic leaflets, stenosis with calcific deposition and paravalvular leaks. The global mortality rate was 19.15%, higher than the native valve replacement group. The most important predictors of surgical mortality were: 1) poor ventricular function (functional classes III and IV), 2) aortic clamping period, 3) the need of a second prosthetic replacement and 4) the time of prosthetic dysfunction. Thus, we conclude that it is of great importance the early recognition of prosthetic valve dysfunction. The need of special surgical procedures in these cases should be evaluated in order to reduce morbidity and mortality.

Asunto(s)

Prótesis Valvulares Cardíacas , Adolescente , Adulto , Femenino , Prótesis Valvulares Cardíacas/mortalidad , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias , Falla de Prótesis , Estudios Retrospectivos , Resultado del Tratamiento

RESUMEN

Partial pericardial tamponade is a critical situation frequently misdiagnosed. We describe five patients with this entity during an urgent surgical reintervention performed few hours after the initial one. We found clots compressing cardiac cavities in all, usually in the right atrium. In one of them we found also a clot compressing the left atrium. None of the patients studied had the classical clinical features of cardiac tamponade (Kussmaul's sign: pulsus paradoxus) and we found no difference in blood pressure, quantity of bleeding or pulmonary capillary pressure, considering the reinterventional moment in comparison to the values taken immediately after the initial surgery and the ones registered during the surgical reintervention. There was significative increase in the central venous pressure value, decreased urine output and drop in the cardiac index. Based on this observation, we believe it is possible to have a presumptive diagnosis of partial pericardial tamponade by bidimensional echocardiographic studies just before the surgical reintervention.

Asunto(s)

Procedimientos Quirúrgicos Cardíacos/efectos adversos , Taponamiento Cardíaco/diagnóstico , Pericardio , Adulto , Taponamiento Cardíaco/etiología , Taponamiento Cardíaco/fisiopatología , Diuresis , Femenino , Humanos , Masculino , Complicaciones Posoperatorias

RESUMEN

Two-hundred-fifty-eight patients who had cardiac surgery with extracorporeal circulation were studied to determine the frequency and significance of conduction disturbances. Fifty-eight (34%) developed new postoperative conduction defects. Seventeen patients developed new conduction alterations after coronary artery bypass graft. The most common disturbance was transient bifascicular block (right bundle branch block and anterior subdivision block of the left bundle branch of His) (p less than 0.01). After valvular surgery twenty-one patients developed conduction defects. Of those the most common disturbance was high degree AV block (57%). The authors found no relation between the AV block and the number of valves operated on or type of valvular surgery. After congenital heart surgery, twenty patients developed conduction defects. The most common defect was high degree AV block. The frequency of complete heart block was higher after the closure of atrial septal defects (P less than 0.01). None of the conduction defects were related to the amount of time the patient was exposed to extracorporeal circulation or to postoperative myocardial infarction. All conduction defects were transient except complete heart block in some patients with ventricular septal defect surgery. In this study there were no hemodynamic complications or mortality associated with the conduction disturbances.

Asunto(s)

Procedimientos Quirúrgicos Cardíacos/efectos adversos , Circulación Extracorporea/efectos adversos , Bloqueo Cardíaco/etiología , Complicaciones Posoperatorias/etiología , Adulto , Niño , Preescolar , Puente de Arteria Coronaria/efectos adversos , Femenino , Cardiopatías Congénitas/cirugía , Enfermedades de las Válvulas Cardíacas/cirugía , Humanos , Masculino , Persona de Mediana Edad

RESUMEN

In order to know early and late results of pericardiectomy on the treatment of chronic constrictive pericarditis in the Instituto Nacional de Cardiología Ignacio Chávez, we review the records of 58 patients with the diagnosis of constrictive pericarditis who underwent surgical treatment between 1947 to 1987. Tuberculosis was the most frequent cause (68.3%) followed by idiopathic cases (24.1%). Preoperatively 3.4% were in New York Heart Association Class I, 31% in Class II, 48.3% in Class III and 17.2% in Class IV. There were 4 in-hospital deaths (overall operative mortality 6.89%). Operative mortality in the last ten years was 0%. Low output was the most common nonfatal complication of pericardiectomy (15.5%). Accidental right atrial tear happened in 8.6%. Mean post-operative follow-up was 5.6 +/- 6.3 years (longest 25.6 years). Mortality per patient year was 2.04%. Actuarial survival estimates were 82% and 71% at 5 to 10 years respectively. Postoperatively 76% were in New York Heart Association Class I (p less than 0.001), 16% in Class II (p less than 0.001), 8% in Class III (p less than 0.001) and none in Class IV (p less than 0.05). Operative mortality, long-term survival and post-operative functional Class were not significantly influenced by preoperative functional Class nor by the duration of symptoms. We conclude that pericardiectomy is an effective treatment of symptomatic chronic constrictive pericarditis because it provides an important and durable improvement in symptoms and functional Class, and it has a low operative mortality.

Asunto(s)

Pericarditis Constrictiva/cirugía , Pericardio/cirugía , Adolescente , Adulto , Anciano , Gasto Cardíaco Bajo/etiología , Niño , Enfermedad Crónica , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Pericarditis Constrictiva/etiología , Pericarditis Constrictiva/mortalidad , Pericarditis Tuberculosa/complicaciones , Complicaciones Posoperatorias/etiología

RESUMEN

We studied 28 patients to whom a prosthestic valve of bovine pericardium manufactured in the Instituto Nacional de Cardiología Ignacio Chávez (INCICH) were implanted in aortic position, from February 1983 to May 1985. We analyzed the clinic follow-up and the prosthetic function was studied by Phonocardiography, Echocardiography M mode, Two-Dimensional and pulsed wave Doppler recordings obtained before and after surgery. The patient were 26 males, 2 females whose age varied from 12 to 66 years. The aortic valve disease was rheumatic in 12, congenital in 11 and of other type in 5. After surgery 26 patients are in functional class I, one in class II and one died, but death was not related to prosthetic valve function. In the Phonocardiogram we observed significant diminution of the ventricular ejection time of 32 +/- 2 msec. to 29 +/- 2 msec. (P less than 0.05), the aortic valve opening sound was of less intensity than the valve closure sound, with relation between both of 0.53. All of them had a systolic ejection murmur. In the Echocardiogram we observed a significant decrease of the end diastolic diameter of 53 +/- 11 mm to 45 +/- 10 mm (P less than 0.05), the end systolic diameter decreased from 37 +/- 13 mm to 33 +/- 10 mm., but the difference was not significant. The aortic prosthetic flow by pulsed Doppler Echocardiography had a maximum velocity of 137 +/- 23 cm/sec., it represents a valvular gradient of 7.5 +/- 0.02 mmHg. Early diastolic regurgitant flow was recorded in two patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Asunto(s)

Bioprótesis , Prótesis Valvulares Cardíacas , Adolescente , Adulto , Anciano , Válvula Aórtica , Niño , Ecocardiografía , Estudios de Evaluación como Asunto , Femenino , Humanos , Masculino , México , Persona de Mediana Edad , Fonocardiografía

RESUMEN

Coronary heart disease is the main cause of mortality among uremic patients on chronic hemodialysis (CHD) and is the determinant of the outcome in these cases after renal transplantation, especially in diabetics. In this study we report our experience with two uremic diabetics on CHD with severe coronary artery lesions in whom aortocoronary bypass was performed before renal transplantation. The outcome in the two patients, after 30 and 55 months respectively indicates successful results. We discuss the necessity to perform coronariography in all the high risk patients on CHD, such as diabetics and elderly before planning renal transplantation and achieve aortocoronary bypass surgery in those with severe coronary disease. The technics and difficulties of the surgery in uremics are also analized.

Asunto(s)

Puente de Arteria Coronaria , Enfermedad Coronaria/cirugía , Complicaciones de la Diabetes , Fallo Renal Crónico/terapia , Trasplante de Riñón , Diálisis Renal , Adulto , Enfermedad Coronaria/etiología , Humanos , Masculino , Persona de Mediana Edad , Diálisis Renal/efectos adversos

Asunto(s)

Circulación Coronaria , Contrapulsador Intraaórtico , Contracción Miocárdica , Angina Inestable/terapia , Procedimientos Quirúrgicos Cardíacos , Cateterismo/métodos , Humanos , Contrapulsador Intraaórtico/efectos adversos , Contrapulsador Intraaórtico/instrumentación , Choque Cardiogénico/terapia

RESUMEN

UNLABELLED: We studied 120 insertions of the Swan-Ganz catheter in 119 patients who needed hemodynamic monitorization for cardiovascular surgery. All catheter insertions were carried out soon after the anesthetic induction employing the modified Seldinger technique through the internal jugular vein, taking as reference the intracavitary pressure waves to get the pulmonary artery wedge position. The time of insertion, time of use, complications of puncture, difficulty and complications of insertion, thoracic and pulmonary complications, and loop or knot in the catheter were examined. RESULTS: multiple punctures in 15 cases (12.5%), 8 carotid artery punctures (6.6%), 14 hematomas (11.6%), difficulty for pass through the right ventricle in 8 cases (6.6%) and pulmonary artery in 32 (26.6%) impossibility to get the pulmonary wedge position in 13 cases (10.8%), loop of catheter in 3 (2.5%), ectopic atrial beats in 30 cases (25%), atrial tachycardia in 4 (3.3%), ectopic ventricular beats in 73 (60.8%). General arrhythmia incidence was 67.5%, none serious. All complications were minor and not life-threatening. Only in two cases (1.6%) the complications were major, both pulmonary infarction, but were life-threatening to patients; in 20 patients (16.6%) the outcome was without complications. There were no deaths for the catheter use. The results of this study showed that complications caused by the pulmonary artery flotation catheter were smaller than the benefit obtained in the management of these patients.

Asunto(s)

Cateterismo Cardíaco/efectos adversos , Cardiopatías/cirugía , Adolescente , Adulto , Anciano , Arritmias Cardíacas/etiología , Cateterismo Cardíaco/instrumentación , Niño , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Embolia Pulmonar/etiología

RESUMEN

We study the phonocardiogram, M mode, two-dimensional and Doppler pulsed echocardiogram of 30 patients, who underwent implantation of a bovine pericardial bioprosthesis manufactured at the Instituto Nacional de Cardiología Ignacio Chávez. We describe 26 patients with prosthesis in mitral position, 22 females and 4 males, with age between 19 to 60 years. After surgery, 22 were in functional I and 2 in class II of the New York Heart Association Criteria. Two patients (6.6%) died of extracardiac complications. Phonocardiogram: Mitral prosthesis closing click (MPCC) were recorded at all, the interval Q wave-MPCC was of 0.09 +/- 0.02 sec. The interval second sound-mitral prosthesis opening click (S2-MPOC) measured 0.10 +/- 0.01 sec. Mid-diastolic murmur were recorded in 8 patients (30.7%). The O-F slope of the apexcardiogram was of 82 +/- 40 mm/sec. Ten patients had tricuspid insufficiency. Echocardiogram: The D-E velocity of mitral prosthesis opening was of 318 +/- 99 mm/sec and the E-F slope velocity of 15 +/- 6.2 mm/sec. All patients except one showed paradoxical motion of the intraventricular septum. The prosthesis stents distance was of 14.1 +/- 2 mm, the internal diameter of 17.8 +/- 2.9 mm and the valvular area was calculated in 2.5 +/- 0.08 cm2. The flow velocity/diameter was 62.6 +/- 26.8 cm/sec/mm and the flow velocity/opening area of 52.5 +/- 26.1 cm/sec/cm2.(ABSTRACT TRUNCATED AT 250 WORDS)

Asunto(s)

Bioprótesis , Prótesis Valvulares Cardíacas , Adulto , Ecocardiografía , Femenino , Estudios de Seguimiento , Enfermedades de las Válvulas Cardíacas/fisiopatología , Enfermedades de las Válvulas Cardíacas/cirugía , Humanos , Masculino , Persona de Mediana Edad , Fonocardiografía , Diseño de Prótesis

RESUMEN

We studied 53 patients within 12 hs from the onset of symptoms of acute myocardial infarction, and 25 healthy controls. We searched for complement split products in plasma treated with EDTA to avoid in vitro complement activation. Therefore the presence of proteolytic degradation products of C3 signals in vivo activation. Sixteen of the 53 cases (30%), had C3 splitting products in EDTA-plasma. In contrast only 2 (8%) controls showed C3 splitting products. In vivo complement activation correlated with the severity of the infarction.

Asunto(s)

Activación de Complemento , Infarto del Miocardio/inmunología , Complemento C3/análisis , Femenino , Humanos , Masculino , Infarto del Miocardio/patología

RESUMEN

The results obtained with some types of bioprostheses together with the present economical situation of the country pointed out that the manufacture of another type of bioprostheses was necessary. After a careful analysis of the results that had been reported in the literature with the diverse types of bioprostheses had been made, it was concluded that pericardial valves were the best choice for our specific requirements. The first problem that had to be solved was the identification of the adequate fraction of purified glutaraldehyde that would provide for adequate tissue fixation. This was determined using several types of biophysical and biochemical techniques. The next step was to find the adequate manufacturing techniques that would provide us with optimal function valves. This was achieved by testing the functional characteristics of these valves on a cardiac cycle simulator. The first group of 132 patients that received this type of valve includes 9 multiple valve replacements, 24 aortic, 98 mitral and 1 pulmonary valve replacements. All the surviving patients have shown a clear improvement and they all show adequate function of their bioprostheses. The function of the valves has not been involved in any of the patient deaths. Since there has not been any evidence of disfunction, these results show that the manufacturing techniques and the design of these bioprostheses is adequate. Naturally to long-term durability of these valves will have to wait before it can be valorated.

Asunto(s)

Bioprótesis , Prótesis Valvulares Cardíacas , Adolescente , Adulto , Animales , Bovinos , Niño , Estudios de Evaluación como Asunto , Femenino , Fijadores , Glutaral , Enfermedades de las Válvulas Cardíacas/cirugía , Humanos , Masculino , Persona de Mediana Edad , Pericardio , Diseño de Prótesis