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1.
Circulation ; 104(12 Suppl 1): I29-35, 2001 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-11568026

RESUMEN

BACKGROUND: Edge-to-edge approximation of the mitral valve leaflets (Alfieri procedure) is a novel surgical treatment for patients with ischemic mitral regurgitation (IMR). Long-term durability may be limited if abnormal mitral leaflet stresses result from this procedure. The aim of the current study was to measure Alfieri stitch tension (F(A)) and to explore its geometric determinants in an ovine model of acute IMR as a reflection of the mitral leaflet stresses imposed by the procedure. METHODS AND RESULTS: Eight sheep were studied immediately after surgical placement of (1) a force transducer interposed between sutures approximating the central leaflet edges and (2) radiopaque markers around the mitral annulus and leaflet edges. Computer-aided analysis of videofluorograms was used to obtained 3D marker coordinates. Simultaneous measurements of F(A), septal-lateral annular dimension (L(S-L)), leaflet edge separation (L(SEP)), anterior (L(AL)) and posterior (L(PL)) leaflet length, and hemodynamic variables were obtained at baseline (CTL) and during acute IMR (circumflex artery occlusion). F(A) was significantly elevated throughout the cardiac cycle during IMR compared with CTL, with maximum F(A) in diastole (0.26+/-0.05 versus 0.46+/-0.08 N, CTL versus IMR; P<0.05). Multivariable analysis revealed L(S-L) as the single independent predictor of maximum F(A) (P<0.001). Positive linear correlations were shown between values of F(A) and L(AL) and L(PL) (dependent variables). CONCLUSIONS: These experimental data demonstrate higher F(A) during IMR and cyclic changes in F(A) closely paralleling changes in L(S-L), eg, being greatest in diastole when the annulus is largest. Increased F(A) during IMR is probably indicative of successful therapeutic intent, but higher diastolic leaflet stresses resulting from persistent or progressive mitral annular dilatation may adversely affect repair durability. This indirectly implies that concomitant mitral ring annuloplasty should be added to the Alfieri repair.


Asunto(s)
Procedimientos Quirúrgicos Cardíacos , Insuficiencia de la Válvula Mitral/cirugía , Válvula Mitral/cirugía , Isquemia Miocárdica , Técnicas de Sutura , Enfermedad Aguda , Animales , Diástole , Modelos Animales de Enfermedad , Ecocardiografía Doppler , Ecocardiografía Doppler en Color , Fluoroscopía/métodos , Hemodinámica , Válvula Mitral/diagnóstico por imagen , Válvula Mitral/fisiopatología , Insuficiencia de la Válvula Mitral/complicaciones , Insuficiencia de la Válvula Mitral/diagnóstico , Insuficiencia de la Válvula Mitral/fisiopatología , Análisis Multivariante , Isquemia Miocárdica/complicaciones , Ovinos , Estrés Mecánico , Sístole
2.
Circulation ; 104(12 Suppl 1): I47-53, 2001 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-11568029

RESUMEN

BACKGROUND: Dilated cardiomyopathy is often associated with mitral regurgitation (MR), or so-called functional MR, the mechanism of which continues to be debated. We studied the valvular and ventricular 3D geometric perturbations associated with MR in an ovine model of tachycardia-induced cardiomyopathy (TIC). METHODS AND RESULTS: Nine sheep underwent myocardial marker implantation in the left ventricle (LV), mitral annulus, and mitral leaflets. After 5 to 8 days, the animals were studied with biplane videofluoroscopy (baseline), and mitral competence was assessed by transesophageal echocardiography. Rapid ventricular pacing (180 to 230 bpm) was subsequently initiated for 15+/-6 days until the development of TIC and MR, whereupon biplane videofluoroscopy and transesophageal echocardiography studies were repeated. LV volume was calculated from the epicardial marker array. Valve closure time was defined as the time after end diastole when the distance between leaflet edge markers reached its minimal plateau. TIC resulted in increased LV end-diastolic volume (P=0.001) and LV end-systolic volume (P=0.0001) and greater LV sphericity (P=0.02). MR increased significantly (grade 0.2+/-0.3 versus 2.2+/-0.9, P=0.0001), as did mitral annulus area (817+/-146 versus 1100+/-161 mm(2), P=0.0001) and mitral annulus septal-lateral diameter (28.2+/-3.5 versus 35.1+/-2.6 mm, P=0.0001). Time of valve closure (70+/-18 versus 87+/-14 ms, P=0.23) and angular displacement of both the anterior (29+/-5 degrees versus 27+/-3 degrees, P=0.3) and posterior (55+/-15 degrees versus 44+/-11 degrees, P=0.13) leaflet edges relative to the mitral annulus after valve closure did not change, but leaflet edge separation after closure increased (5.2+/-0.9 versus 6.8+/-1.2 mm, P=0.019). CONCLUSIONS: MR in TIC resulted from decreased leaflet coaptation secondary to annular dilatation in the septal-lateral direction. These data support the use of annular reduction procedures, such as rigid, complete ring annuloplasty, to address functional MR in patients with dilated cardiomyopathy.


Asunto(s)
Cardiomiopatía Dilatada/fisiopatología , Insuficiencia de la Válvula Mitral/fisiopatología , Taquicardia/fisiopatología , Animales , Estimulación Cardíaca Artificial , Cardiomiopatía Dilatada/etiología , Modelos Animales de Enfermedad , Ecocardiografía Transesofágica , Ventrículos Cardíacos/diagnóstico por imagen , Ventrículos Cardíacos/fisiopatología , Hemodinámica , Válvula Mitral/diagnóstico por imagen , Válvula Mitral/fisiopatología , Insuficiencia de la Válvula Mitral/diagnóstico , Insuficiencia de la Válvula Mitral/etiología , Taquicardia/complicaciones , Disfunción Ventricular Izquierda/diagnóstico por imagen , Disfunción Ventricular Izquierda/fisiopatología
3.
J Heart Valve Dis ; 10(3): 312-9, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11380093

RESUMEN

BACKGROUND AND AIM OF THE STUDY: Ovine mitral valve closure is associated with presystolic mitral annular reduction coincident with atrial contraction, which is abolished with ventricular pacing. Whether lack of properly timed atrial contraction influences mitral valve closure or competence, however, is not known. METHODS: Eight sheep underwent myocardial marker implantation on the left ventricle, mitral annulus (MA), and mitral leaflets. After 7-10 days, the animals were studied with biplane videofluoroscopy at baseline and during ventricular or atrioventricular (AV) sequential pacing. Valve closure was timed from end-diastole (ED) and defined as minimum distance between two leaflet edge markers. ED was defined as peak of ECG R wave, end-systole as peak negative left ventricular (LV) dP/dt, and end-isovolumic contraction (EIVC) as 83.5 ms after ED. Septal-lateral (S-L) annular diameter was defined as distance between two markers at the middle of the anterior and posterior annulus. Regurgitant volume (RV) was calculated as relative volume change between ED and EIVC. RESULTS: V-pacing was associated with delayed leaflet closure (65 +/- 5 versus 29 +/- 10 ms, p = 0.008); moreover, RV (4.1 +/- 0.5 versus 1.4 +/- 0.5 ml, p = 0.02), end-diastolic S-L diameter (2.87 +/- 0.10 versus 2.67 +/- 0.09 cm, p = 0.0005), and MA area (8.12 +/- 0.37 versus 7.26 +/- 0.31 cm2, p = 0.009) all increased. RV and leaflet and annular dynamics during AV-pacing were similar to baseline. CONCLUSION: V-pacing increased S-L MA diameter by only 8 +/- 1%, but this change was associated with delayed leaflet coaptation and a 16 +/- 1% regurgitant fraction. These findings provide direct evidence that a properly timed atrial contraction is functionally important for effective mitral leaflet closure.


Asunto(s)
Función Atrial/fisiología , Insuficiencia de la Válvula Mitral/fisiopatología , Válvula Mitral/fisiopatología , Contracción Miocárdica/fisiología , Ovinos , Animales , Estimulación Cardíaca Artificial , Modelos Animales de Enfermedad , Electrocardiografía , Fluoroscopía , Hemodinámica/fisiología , Imagenología Tridimensional , Válvula Mitral/diagnóstico por imagen , Insuficiencia de la Válvula Mitral/diagnóstico por imagen
4.
Eur J Cardiothorac Surg ; 19(4): 431-7, 2001 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11306308

RESUMEN

OBJECTIVE: The edge-to-edge (Alfieri) mitral repair technique appears to be clinically promising, but the potential for functional mitral stenosis, especially with exercise, remains a concern. We used the myocardial marker method combined with Doppler echocardiography to evaluate mitral annular (MA) three-dimensional (3-D) dynamics and transvalvular gradients after leaflet approximation before and during dobutamine infusion. METHODS: Eight adult sheep underwent implantation of eight myocardial markers around the MA and nine in the left ventricle. Mitral leaflet edges were approximated at the valve center and micromanometers were placed in the left ventricle and atrium. The animals were studied with biplane videofluoroscopy to determine 3-D marker coordinates for computation of precise 3-D MA area and left ventricular (LV) volume. Epicardial Doppler echocardiography measured peak and mean diastolic mitral valve gradients at baseline and during dobutamine infusion (10 microg/kg per min). RESULTS: During dobutamine stimulation, left ventricular dP/dt increased from 1776+/-712 to 3390+/-618 mmHg/s (P=0.002), and cardiac output (CO) increased from 2.7+/-1.1 to 5.1+/-1.2 l/min (P=0.009). Mitral annular area (MAA) at end-diastole (ED) fell from 8.6+/-1.4 to 7.0+/-1.8 cm(2) (P=0.001) with inotropic stimulation, but only a modest increase was observed in mean (1.4+/-0.4 vs. 2.4+/-1.0 mmHg, P=0.046) and peak (2.7+/-0.8 vs. 4.9+/-2.5 mmHg, P=0.03) diastolic mitral valve gradients. MAA changed dynamically throughout the cardiac cycle, reflecting normal physiology, but the magnitude of MAA change was augmented during inotropic stimulation (18+/-5% and 27+/-4% for control and dobutamine, respectively; P=0.004). CONCLUSION: Dobutamine increased CO by 89% and decreased ED annular area by 19% after edge-to-edge repair, yet only a small increase in valve gradient occurred. Marker analysis showed enhanced dynamic motion of the mitral annulus. Thus, the edge-to-edge mitral valve repair was not associated with substantial transvalvular obstruction during high flow conditions and did not perturb normal MA 3-D dynamics in normal ovine hearts.


Asunto(s)
Procedimientos Quirúrgicos Cardíacos , Válvula Mitral/fisiología , Válvula Mitral/cirugía , Animales , Fenómenos Biomecánicos , Gasto Cardíaco , Cardiotónicos/farmacología , Dobutamina/farmacología , Hemodinámica , Procesamiento de Imagen Asistido por Computador , Masculino , Válvula Mitral/efectos de los fármacos , Modelos Animales , Ovinos
5.
J Heart Valve Dis ; 10(6): 767-73, 2001 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11767184

RESUMEN

BACKGROUND AND AIM OF THE STUDY: Changes in the dimensions of 'He's triangle' (formed by mitral leaflet segments subtending two associated chordae tendineae) derived from data obtained in in-vitro mitral valve models have been proposed to provide a mechanistic explanation for mitral leaflet malcoaptation. The in-vivo dynamics of He's triangle, however, have not been hitherto determined. METHODS: Radio-opaque markers were placed in 13 sheep to delineate the mitral annulus and four (of an infinite number of possible) He's triangles formed by: (i) the anterior mitral leaflet (AML), first- (CT1) and second-order (CT2) chordae tendineae emanating from the anterior papillary tip (APT1) as well as from the posterior papillary tip (PPT1), respectively; and (ii) the posterior mitral leaflet (PML), CT1 and CT2 emanating from other loci on the anterior as well as the posterior papillary tips (APT2 and PPT2), respectively. Immediately postoperatively (anesthetized, open-chest), three-dimensional end-systolic marker positions were measured before and during circumflex coronary artery occlusion sufficient to produce mitral regurgitation, as verified by echocardiography. RESULTS: During ischemia, three leaflet segments constituting one side of three He's triangles elongated: The AML attached to APT1 and to PPT1 by 1.5+/-1.2 mm (p <0.001) and 1.3+/-0.8 mm (p <0.001), respectively, and the posterior leaflet attached to APT2 by 1.4+/-1.9 mm (p = 0.02). Apart from a 0.9+/-1.1 mm (p = 0.02) increase in the length of CT2 attached to APT2, the length of the seven other CT1 and CT2 remained relatively unchanged during acute left ventricular ischemia. CONCLUSION: With acute posterolateral ischemia, the lengths of CT1 and CT2 remained relatively constant, but the AML and PML lengths were not constant as the AML and PML 'unfurled' during acute left ventricular ischemia. These geometric changes may provide further insight into the mechanisms of acute ischemic mitral regurgitation, though it is not clear how they will be clinically helpful.


Asunto(s)
Cuerdas Tendinosas/patología , Imagenología Tridimensional , Válvula Mitral/patología , Isquemia Miocárdica/complicaciones , Isquemia Miocárdica/patología , Músculos Papilares/patología , Disfunción Ventricular Izquierda/etiología , Disfunción Ventricular Izquierda/patología , Enfermedad Aguda , Animales , Cuerdas Tendinosas/fisiopatología , Modelos Animales de Enfermedad , Hemodinámica/fisiología , Masculino , Válvula Mitral/fisiopatología , Isquemia Miocárdica/fisiopatología , Músculos Papilares/fisiopatología , Ovinos , Disfunción Ventricular Izquierda/fisiopatología
6.
J Thorac Cardiovasc Surg ; 120(5): 966-75, 2000 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11044323

RESUMEN

BACKGROUND: The perturbed mitral leaflet geometry that leads to acute ischemic mitral regurgitation during acute left ventricular ischemia has not been quantified, nor is it known whether annuloplasty rings affect these detrimental changes in leaflet geometry. METHODS: Radiopaque markers were implanted on both mitral leaflets and around the anulus in 3 groups of sheep: one group without rings served as the control group (n = 7); the others underwent Duran (n = 6; Medtronic Heart Valve Division, Minneapolis, Minn) or Carpentier-Edwards Physio (n = 5; Baxter Cardiovascular Division, Santa Ana, Calif) ring annuloplasty. After recovery, 3-dimensional marker coordinates were obtained by means of biplane videofluoroscopy before and during acute posterolateral left ventricular ischemia. Leaflet geometry was defined by measuring distances between annular and leaflet markers and perpendicular distances to the leaflet markers from a best-fit annular plane. RESULTS: In all control animals, left ventricular ischemia was associated with acute ischemic mitral regurgitation and apical displacement (away from the annular plane) of the posterior leaflet edge and base markers by 0.6 +/- 0.4 mm (P =.01) and 0.7 +/- 0.2 mm (P <.001), respectively. The distance between the posterior leaflet markers and the mid-posterior anulus did not change significantly during ischemia. The anterior leaflet edge marker extended 1.0 +/- 0. 5 mm (P =.01) away from the mid-anterior anulus during ischemia, but compared with its nonischemic position, the anterior leaflet was not displaced apically away from the annular plane. In all animals in the Duran and Physio groups, leaflet geometry was unchanged during ischemia, and acute ischemic mitral regurgitation was not detected. CONCLUSION: Acute ischemic mitral regurgitation was associated with restricted motion of the posterior leaflet and extension of the anterior leaflet. Annuloplasty rings prevented these geometric perturbations of the mitral leaflets during acute left ventricular ischemia and preserved valvular competence.


Asunto(s)
Implantación de Prótesis de Válvulas Cardíacas , Insuficiencia de la Válvula Mitral/fisiopatología , Insuficiencia de la Válvula Mitral/cirugía , Isquemia Miocárdica/complicaciones , Animales , Hemodinámica , Procesamiento de Imagen Asistido por Computador , Análisis de los Mínimos Cuadrados , Masculino , Válvula Mitral/anatomía & histología , Válvula Mitral/fisiología , Insuficiencia de la Válvula Mitral/complicaciones , Ovinos , Disfunción Ventricular Izquierda/complicaciones
7.
Surgery ; 128(2): 361-7, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10923017

RESUMEN

INTRODUCTION: Ovine mitral annular area (MAA) reduction predominantly occurs before ventricular systole. We used the myocardial marker methods to investigate left atrial and MAA dynamics during rapid atrial pacing. METHODS: Seven sheep underwent implantation of 21 myocardial markers around the mitral annulus, the left ventricle and left atrium. After 7 to 10 days, animals were studied with biplane videofluoroscopy to determine 3-dimensional marker coordinates unpaced and during rapid atrial pacing at 140 minutes(-1). Left ventricle volume, left atrial volume (LAV), and MAA were calculated from marker coordinates. End diastole (ED) was defined at peak of the electrocardiogram R wave; times of minimum MAA and minimum LAV were expressed relative to ED (t = 0). Percent reduction in MAA and LAV were calculated from maximum and minimum values between diastole and early systole. RESULTS: The time of minimum MAA occurred earlier relative to ED during rapid pacing compared with control (-48 +/- 21 vs 19 +/- 14 msec; P <.001), as did the time of minimum LAV (-47 +/- 18 vs 4 +/- 16 msec; P <.001). Minimum MAA and LAV were significantly smaller with rapid pacing (6. 8 +/- 0.6 vs 6.5 +/- 0.5 cm(2); P <.05, respectively; and 15.4 +/- 2. 4 vs 16.5 +/- 2.3 mL; P <.01, respectively), and a relatively greater fractional reduction in MAA and LAV was observed during presystole. CONCLUSIONS: Rapid atrial pacing resulted in greater MAA and LAV reduction, both of which occurred entirely during diastole. This study supports the notion that MAA reduction is closely linked to LA dynamics.


Asunto(s)
Fibrilación Atrial/fisiopatología , Estimulación Cardíaca Artificial , Frecuencia Cardíaca/fisiología , Hemodinámica , Válvula Mitral/fisiopatología , Animales , Diástole , Electrocardiografía , Válvula Mitral/fisiología , Ovinos , Sístole , Factores de Tiempo , Función Ventricular Izquierda
8.
Ann Thorac Surg ; 68(5): 1727-30, 1999 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-10585049

RESUMEN

BACKGROUND: We describe our experience with a technique of cusp commissuroplasty to reconstruct atrioventricular valves damaged by endocarditis of the commissure and adjacent cusps. METHODS: We operated on 3 patients with mitral endocarditis and one patient with previous tricuspid endocarditis. Infected leaflet tissue was excised from each side of the commissure, leaving a defect between one quarter and one third of the valve area. Using the technique of valve commissuroplasty, leaflet remnants were reapposed at the cut edges to obliterate the commissure. The residual D-shaped defect between the apposed leaflets and annulus was either closed directly or patched with pericardium, depending on the size of the defect. RESULTS: Constructing unicommissural mitral and bicuspid tricuspid valves restored leaflet continuity. One patient was lost to follow-up. Postoperative echocardiography performed at a mean interval of 14.7 months showed competent and nonobstructed valves. There was no recurrent endocarditis at a mean follow-up time of 15.7 months. CONCLUSIONS: The technique of cusp commissuroplasty can be used to reconstruct atrioventricular valves that have been damaged by endocarditis of the commissure and adjacent cusps.


Asunto(s)
Endocarditis Bacteriana/cirugía , Enfermedades de las Válvulas Cardíacas/cirugía , Válvula Mitral/cirugía , Infecciones Estafilocócicas/cirugía , Válvula Tricúspide/cirugía , Adolescente , Adulto , Implantación de Prótesis Vascular , Niño , Femenino , Estudios de Seguimiento , Humanos , Masculino , Técnicas de Sutura
9.
Ann Thorac Cardiovasc Surg ; 5(6): 391-5, 1999 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-10637390

RESUMEN

OBJECTIVE: By using a T-graft configuration, the myocardium may be completely revascularized with bilateral internal thoracic arteries. This study aimed to evaluate the perioperative morbidity and mortality in a single surgeon's early experience with a modified T-graft using bilateral internal thoracic arteries. METHODS: Between October 1994 to April 1997, 200 consecutive patients mostly selected per protocol, received a T-graft with bilateral internal thoracic arteries for stable angina pectoris (n = 157) or unstable angina pectoris (n = 43). The mean age of patients was 56 years (range of 36 to 78 years). There were 171 males and 29 females. Forty-three patients had diabetes. Concomitant procedures were performed in 8 patients. RESULTS: In 190 patients (95%), total arterial revascularization of the myocardium was achieved solely by the use of bilateral internal thoracic arteries in a T-graft configuration and the number of anastomoses per patient averaged 4.2. Ten patients (5%) received supplemental saphenous veins in addition to T-grafts for low cardiac output (n = 3), intraoperative regional ischaemia (n = 2), postoperative myocardial ischaemia (n = 2) and inadequate conduits (n = 3). The 30-day mortality was 0.5%. Perioperative myocardial infarct occurred in 2 patients (1.0%). Reasons encountered for early re-operation included bleeding (n = 7), sternal dehiscence (n = 5), suppurative sternitis (n = 3) and myocardial ischaemia (n = 2). Twelve patients received inotropes and intraaortic balloon counterpulsation was employed in 3 patients. CONCLUSION: When bilateral internal thoracic arteries were used in a T-graft configuration, total arterial revascularization of the myocardium was achieved with an acceptably low morbidity and mortality.


Asunto(s)
Puente de Arteria Coronaria/métodos , Arterias Torácicas/trasplante , Adulto , Anciano , Anastomosis Quirúrgica/efectos adversos , Anastomosis Quirúrgica/métodos , Angina de Pecho/cirugía , Angina Inestable/cirugía , Gasto Cardíaco Bajo/cirugía , Cardiotónicos/uso terapéutico , Estudios de Cohortes , Puente de Arteria Coronaria/efectos adversos , Complicaciones de la Diabetes , Femenino , Humanos , Contrapulsador Intraaórtico , Complicaciones Intraoperatorias/cirugía , Masculino , Persona de Mediana Edad , Infarto del Miocardio/etiología , Isquemia Miocárdica/cirugía , Complicaciones Posoperatorias/cirugía , Hemorragia Posoperatoria/cirugía , Estudios Prospectivos , Reoperación , Vena Safena/trasplante , Esternón/cirugía , Dehiscencia de la Herida Operatoria/cirugía , Infección de la Herida Quirúrgica/cirugía , Tasa de Supervivencia
10.
Ann Thorac Surg ; 68(6): 2364-5, 1999 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-10617046

RESUMEN

We describe a technique of mini-thoracotomy to plicate the paralyzed hemidiaphragm with thoracoscopic assistance. Most of the hemidiaphragm can be plicated expeditiously under direct vision with light derived from a posterior thoracoscope placed in the auscultatory triangle. Videoscopic vision is employed only occasionally when the view of the posteromedial hemidiaphragm is obscured. Continuous suture traction can be easily applied through the mini-thoracotomy, thus maintaining suture tension and enabling maximal inversion of the elevated hemidiaphragm.


Asunto(s)
Diafragma/cirugía , Toracoscopía , Toracotomía/métodos , Humanos , Procedimientos Quirúrgicos Mínimamente Invasivos , Parálisis/etiología , Nervio Frénico/lesiones , Parálisis Respiratoria/cirugía
11.
J Dairy Sci ; 80(10): 2249-57, 1997 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9361196

RESUMEN

Commercial extracts from oro-pharyngeal tissues of goats and kids have been used as the source of pregastric lipase and have been processed to yield partially purified samples of the primary pregastric lipase. The activity of these lipases against tributyrylglycerol has been determined over a range of pH and temperatures. Optimum pH conditions for pregastric lipase ranged from pH 5.6 to 6.5 for goats and from pH 5.5 to 6.2 for kids, respectively; the optimum temperature ranged from 43 to 60 degrees C. Optima for kid lipase extended slightly below pH 5.5 and higher than 60 degrees C; which were the limits of the test conditions. The enzymes were also used as catalysts for the hydrolysis of monoacid triglycerides (C4:0 to C12:0) at 40 degrees C and pH 6.5; activity was maximum against tributyrylglycerol (C4:0). Values for the Michaelis-Menten constant, increased as carbon chain length of the carboxylic moiety on the triglycerides increased, but values were identical for pregastric lipases of both goats and kids. Anhydrous milk fat was hydrolyzed by the commercial extracts of pregastric lipases of goats and kids, and the resulting profiles for free fatty acids were very similar to one another and to the corresponding profile for a commercial sample of Parmesan cheese. There appear to be no significant differences in activity between the enzyme preparations from goats and kids.


Asunto(s)
Cabras/metabolismo , Lipasa/metabolismo , Metabolismo de los Lípidos , Leche/química , Triglicéridos/metabolismo , Animales , Bovinos , Emulsiones , Concentración de Iones de Hidrógeno , Hidrólisis , Cinética , Temperatura
12.
Arch Surg ; 131(7): 703-7, 1996 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-8678767

RESUMEN

OBJECTIVE: To compare the accuracy of whole-body position emission tomography (PET)using [18F]fluorodeoxyglucose (FDG) with conventional radiological imaging techniques in identifying operable colorectal cancer metastases to the liver. DESIGN: A double-blind comparative study of FDG-PET as the criterion standard vs conventional radiological imaging methods as the criterion standard, in staging of recurrent colorectal cancer. SETTING: Institutional practice in a tertiary referral center. PATIENTS: Thirty-four consecutive patients with suspected colorectal cancer metastases recruited for the study between May 1993 and October 1994. INTERVENTIONS: Conventional radiological methods of cancer staging included abdominal computed tomography (CT) (n = 34), chest x-rays (n = 15), and chest CT (n = 19) to evaluate extrahepatic disease. Twenty-seven patients were subsequently considered to have apparently isolated cancer metastases to the liver. Anatomical resectability was assessed by magnetic resonance imaging (n = 24) or CT angiography (n = 3) in all study patients. The FDG-PET studies (n = 34) were performed within 8 weeks of conventional radiological imaging. MAIN OUTCOME MEASURES: Malignancy of suspected lesions detected by means of FDG-PET and conventional radiological imaging was confirmed by histopathologic examination of resected specimens and percutaneous biopsy specimens and by serial CT scans demonstrating progression of disease. RESULTS: Unsuspected extrahepatic malignant disease that was missed by conventional radiological imaging was detected by FDG-PET in 11 patients (32%). The PET-detected extrahepatic malignant disease included retroperitoneal nodal metastases (n = 6), pulmonary metastases (n = 3), and locoregional cancer recurrences (n = 2). The additional information afforded by PET consequently had an influence on the clinical management in 10 patients (29%). CONCLUSIONS: The FDG-PET method enabled selection of patients with apparently curable colorectal cancer metastases to the liver for hepatic resection.


Asunto(s)
Neoplasias Colorrectales/patología , Desoxiglucosa/análogos & derivados , Radioisótopos de Flúor , Neoplasias Hepáticas/diagnóstico por imagen , Neoplasias Hepáticas/secundario , Tomografía Computarizada de Emisión , Método Doble Ciego , Fluorodesoxiglucosa F18 , Humanos , Recurrencia Local de Neoplasia , Radiografía
13.
Melanoma Res ; 6(3): 267-71, 1996 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-8819130

RESUMEN

Hyperthermic isolated limb perfusion (ILP) with melphalan is well established as an effective form of treatment for recurrent melanoma confined to an extremity. High drug concentrations in the limb are readily achieved, without systemic side-effects. However, regional toxicity can lead to considerable morbidity and functional disturbance. This study was undertaken to evaluate factors which might contribute to acute regional toxicity following ILP. Melphalan concentrations in limb blood samples taken at regular intervals during 135 ILPs were measured by HPLC, allowing peak melphalan concentration and area under the curve (AUC) for each procedure to be determined. Acute regional toxicity associated with ILP was found to be significantly correlated with limb tissue temperatures > 40 degrees C, peak melphalan concentration and melphalan AUC, in decreasing order, but was not correlated with tourniquet time. Further studies are required to directly assess melphalan uptake by tumour tissue, and to relate this to both limb toxicity and tumour response.


Asunto(s)
Antineoplásicos Alquilantes/efectos adversos , Quimioterapia del Cáncer por Perfusión Regional , Melanoma/tratamiento farmacológico , Melfalán/efectos adversos , Antineoplásicos Alquilantes/administración & dosificación , Antineoplásicos Alquilantes/farmacocinética , Brazo , Temperatura Corporal , Cromatografía Líquida de Alta Presión , Humanos , Pierna , Melanoma/patología , Melfalán/administración & dosificación , Melfalán/farmacocinética , Tasa de Depuración Metabólica , Torniquetes
14.
Cardiovasc Surg ; 4(3): 384-8, 1996 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-8782943

RESUMEN

Colour duplex scanning is reported to be an accurate non-invasive tool for the diagnosis of lower-extremity arterial disease. The authors at the South Coast Vascular Laboratory have conducted a prospective audit to determine the efficacy of colour duplex scanning in a vascular surgical practice. The aims of this prospective trial were to compare the accuracy of colour duplex scanning with intra-arterial digital subtraction angiography (DSA) in the localization and classification of aortoiliac and femoropopliteal artery disease. Ninety-one lower limbs in 50 patients were evaluated independently by colour duplex scanning and DSA. The lower-limb vasculature was divided into eight segments: infrarenal aorta, common iliac artery, external iliac artery, common femoral artery, proximal, middle and lower thirds of the combined length of the superficial femoral and above-knee popliteal artery, and lastly the below-knee popliteal artery. A total of 558 arterial segments were examined. The Kappa value of duplex scanning compared with 'gold standard' DSA was 0.57. For detecting haemodynamically significant arterial lesions of > 50% reduction in diameter, duplex scanning had a sensitivity of 75%, specificity of 90%, positive predictive value of 77% and negative predictive value of 89% compared with DSA. The level of accuracy obtained does not support the use of duplex as a sole method of investigation for lower-extremity arterial disease in the authors' case. However, the high negative predictive value of colour duplex may be useful in excluding haemodynamically significant disease. This study emphasizes the importance of prospective auditing to determine individual accuracy with duplex examination for arterial disease, and enables clinical decision making to be based on tests with a known accuracy.


Asunto(s)
Angiografía de Substracción Digital , Isquemia/diagnóstico , Pierna/irrigación sanguínea , Ultrasonografía Doppler en Color , Arteriopatías Oclusivas/diagnóstico , Velocidad del Flujo Sanguíneo/fisiología , Humanos , Estudios Prospectivos , Sensibilidad y Especificidad , Resistencia Vascular/fisiología
16.
Aust N Z J Surg ; 66(1): 41-2, 1996 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-8629980

RESUMEN

Laparoscopic endogastric surgery is a novel surgical approach that introduces the viewing laparoscope and instruments into the gastric lumen. The excellent visualization, improved instrument handling and versatility afforded by this technique enable local resection of mucosal lesions that are beyond the scope of peroral endoscopy. The authors describe this particular approach for the excision of gastric villous adenoma and early gastric cancer.


Asunto(s)
Adenoma Velloso/cirugía , Laparoscopía , Neoplasias Gástricas/cirugía , Anciano , Carcinoma in Situ/cirugía , Femenino , Gastroscopía , Humanos , Laparoscopía/métodos , Masculino , Persona de Mediana Edad
17.
Eur J Surg Oncol ; 21(6): 690-1, 1995 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8631424

RESUMEN

The prognosis after surgery for carcinoma of the gallbladder remains poor. Treatment failure is frequently due to loco-regional recurrence in the adjacent liver and regional lymph nodes. We report a case of gallbladder carcinoma with proven involvement of the cystic duct node (Nevin stage IV). Pre-operative intra-arterial induction chemotherapy using two cycles of cisplatin, 5-fluorouracil, doxorubicin and mitomycin C was administered via the common hepatic artery. A radical cholecystectomy was performed 4 weeks later, and histological examination of the resected specimen showed a near total response, with no residual nodal disease. The patient remains well and free of disease 3 years later. Intra-arterial induction chemotherapy warrants further evaluation.


Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Neoplasias de la Vesícula Biliar/tratamiento farmacológico , Arteria Hepática , Infusiones Intraarteriales , Adenocarcinoma/patología , Adenocarcinoma/cirugía , Terapia Combinada , Femenino , Neoplasias de la Vesícula Biliar/patología , Neoplasias de la Vesícula Biliar/cirugía , Humanos , Persona de Mediana Edad
18.
Australas Radiol ; 39(3): 243-5, 1995 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-7487757

RESUMEN

Transluminal angioplasty can be used to relieve symptomatic lower extremity arterial disease with minimal morbidity. This prospective study compares the accuracy of colour-coded duplex ultrasonography with intra-arterial digital subtraction angiography in selection of femoro-popliteal lesions for angioplasty. Isolated, short (< 6 cm) and haemodynamically significant stenosis (> 50% reduction in diameter) were considered for angioplasty. Colour-duplex selection and exclusion was in agreement with angiography in 68 out of 86 lower limbs (79%). The sensitivity, specificity, positive and negative predictive value of colour duplex compared with angiography yielded values of 60.9, 87.5, 60.9 and 85.7%, respectively. The discrepancy between colour duplex and digital subtraction angiography can be partly explained by the tendency of duplex to underestimate the severity and length of disease. It is concluded that colour-coded duplex can be used as a screening tool for lower extremity arterial disease to select appropriate lesions for endovascular procedures. The accuracy of duplex in the present study was not perfect and the decision for further intervention should be based on clinical grounds.


Asunto(s)
Angioplastia de Balón , Pierna/irrigación sanguínea , Ultrasonografía Doppler en Color , Ultrasonografía Doppler Dúplex , Angiografía de Substracción Digital , Arteriopatías Oclusivas/diagnóstico por imagen , Arteriopatías Oclusivas/terapia , Constricción Patológica/diagnóstico por imagen , Arteria Femoral/diagnóstico por imagen , Humanos , Isquemia/diagnóstico por imagen , Isquemia/terapia , Arteria Poplítea/diagnóstico por imagen , Estudios Prospectivos , Sensibilidad y Especificidad
19.
Postgrad Med J ; 71(835): 303-5, 1995 May.
Artículo en Inglés | MEDLINE | ID: mdl-7596940

RESUMEN

A patient with carcinoma of the stomach invading multiple adjacent organs and fungating through the anterior abdominal wall was treated by en bloc multiple organ resection and abdominal wall reconstruction. The patient is alive and well at the time of writing, six months after the operation. The rationale for embarking on multiple organ resection for gastric cancer is discussed. However, such an aggressive surgical approach should only be applied to carefully selected patients who are medically fit and have no evidence of widespread systemic metastases.


Asunto(s)
Adenocarcinoma/cirugía , Gastrectomía , Hígado/cirugía , Pancreatectomía , Esplenectomía , Neoplasias Gástricas/cirugía , Músculos Abdominales/cirugía , Colectomía , Femenino , Humanos , Persona de Mediana Edad , Tasa de Supervivencia
20.
Med J Aust ; 162(7): 345-7, 1995 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-7715513

RESUMEN

OBJECTIVE: To test the hypothesis that somatosensory evoked potentials (SEP) and results of arterial photoplethysmography (PPG) predict outcome after surgery for thoracic outlet syndrome. DESIGN: A retrospective case series which correlated surgical outcome with preoperative SEP and PPG results using Fisher's exact test. PPG results were considered abnormal when there was complete loss of arterial pulsation, and SEP results when amplitudes were reduced and latencies delayed. SETTING: Royal Prince Alfred Hospital, between March 1984 and February 1992. PATIENTS: Forty-six consecutive patients with clinically diagnosed thoracic outlet syndrome were admitted for surgery; sixteen underwent bilateral operations (total of 63 limbs). INTERVENTIONS: After SEP and PPG tests, all patients underwent thoracic outlet decompressive surgery--excision of the first rib, of the cervical rib (where present), and of other congenital anomalies associated with thoracic outlet syndrome--by the axillary approach. MAIN OUTCOME MEASURES: Surgical outcome was graded as good when symptoms improved and the patient returned to work or pre-illness activities. It was graded as poor when symptoms remained unchanged or worsened, or when there was continued inability to work or engage in usual activities. RESULTS: The follow-up period ranged from 1.9-9.8 years (mean, 5.7 years). Significantly more limbs with abnormal SEP or PPG results had a good outcome (49 of 53 limbs; 93%) than limbs with normal SEP and PPG results (six of 10 limbs; 60%) (P = 0.02). CONCLUSIONS: Abnormal SEP and PPG results correlated with a better postsurgical outcome. These tests may therefore aid in determining prognosis of surgery for thoracic outlet syndrome.


Asunto(s)
Síndrome del Desfiladero Torácico/diagnóstico , Adolescente , Adulto , Anciano , Niño , Enfermedad Crónica , Potenciales Evocados Somatosensoriales , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Fotopletismografía/instrumentación , Fotopletismografía/métodos , Pronóstico , Síndrome del Desfiladero Torácico/fisiopatología , Síndrome del Desfiladero Torácico/cirugía , Resultado del Tratamiento
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