Expression of homologues for p53 and p73 in the softshell clam (Mya arenaria), a naturally-occurring model for human cancer.

Homologues for human p53 (Hsp53) and p73 (Hsp73) genes were cloned and expression patterns for their corresponding proteins analysed in tissues from normal and leukemic softshell clams (Mya arenaria). These are the first structural and functional data for p53 and p73 cDNAs and gene products in a naturally occurring, non-mammalian disease model. Core sequence of the predicted clam p53 (Map53) and p73 (Map73) proteins is virtually identical and includes the following highly conserved regions: the transcriptional activation domain (TAD), MDM2 binding site, ATM phosphorylation site, proline rich domain, DNA binding domains (DBDs) II-V, nuclear import and export signals and the tetramerization domain. The core sequence is a structural mosaic of the corresponding human proteins, with the TAD and DBDs resembling Hsp53 and Hsp73, respectively. This suggests that Map53 and Map73 proteins may function similarly to human proteins. Clam proteins have either a short (Map53) or long (Map73) C-terminal extension. These features suggest that Map53 and Map73 may be alternate splice variants of a p63/p73-like ancestral gene. Map73 is significantly upregulated in hemocytes and adductor muscle from leukemic clams. In leukemic hemocytes, both proteins are absent from the nucleus and sequestered in the cytoplasm. This observation suggests that a non-mutational p53/p73-dependent mechanism may be involved in the clam disease. Further studies of these gene products in clams may reveal p53/p73-related molecular mechanisms that are held in common with Burkitt's lymphoma or other human cancers.

[Atherosclerotic ischemic cardiopathy in patients with dextrocardia in situs viscerum inversus]. / Cardiopatía isquémica aterosclerosa en pacientes con dextrocardia en situs viscerum inversus.

We describe the incidence, clinical, radiologic, electrocardiographic, echocardiographic and angiographic findings of two cases with dextrocardia in situ viscerum inversus with ischaemic heart disease. The first patient had coronary artery saphenous bypass graft and is currently asymptomatic with a negative maximal stress test. The other patient with diabetes mellitus and unfavorable coronary anatomy was not operated and is currently with stable angina on class II of the NYHA. The electrocardiographic, echocardiographic and angiographic strategies are commented.

[Medico-surgical experience in dysfunction of heart valve prostheses. Report of 55 cases]. / Experiencia médico-quirúrgica en la disfunción de prótesis valvulares cardíacas. Reporte de 55 casos.

The medical and surgical outcome of 55 patients with prosthetic valve disfunction are reported (39 bioprosthesis and 16 mechanical). Fifty patients were operated and five had medical treatment. The group of patients with mechanical prosthesis had a functional class of 2.4 +/- .74 vs patients with bioprosthesis who had a functional class of 2.8 +/- .71. Forty eight patients (87%) had congestive heart failure, four systemic emboli and three infective endocarditis. Three cases with mechanical prosthesis in tricuspid position were subjected to thrombolysis with streptokinase and experienced clinical and echocardiographical improvement. Time elapsed from original implantation and valve disfunction was 66 +/- 56 months for mechanical prosthesis vs 108 +/- 37 months in bioprosthesis (p less than 0.01), three patients died at surgery and two during the waiting period. All deaths resulted from cardiogenic shock. All of them were previously on functional class IV.

[Balloon valvuloplasty in stenotic bioprosthesis]. / Valvuloplastía con balón en bioprótesis estenóticas.

The results of balloon valvuloplasty performed on five patients with stenotic bioprosthesis treated in the Hospital de Cardiología Centro Médico Nacional Siglo XXI, are presented. All five bioprosthesis were right sided, two in tricuspid position, one in pulmonary valve position and two in valvulated conduits from right ventricle to pulmonary artery. In all cases a pressure gradient reduction was achieved, an improvement of clinical functional class and heart failure manifestations were obtained. Mansfields balloons were used. One in two patients, and two balloons in three. We had not complications with the procedure. We conclude that balloon valvuloplasty on bioprosthesis is a safe and dependable procedure to be used in right sided bioprosthesis.

[Doppler echocardiography assessment of tricuspid valve prosthesis with normal function and with dysfunction due to obstruction]. / Evaluación mediante ecocardiografía Doppler de las prótesis valvulares tricuspídeas con función normal y con disfunción por obstrucción.

UNLABELLED: In order to know the normal ranges of the maximum velocity and the pressure half-time between normal functioning tricuspid prostheses and malfunctioning tricuspid prostheses due to obstruction, we studied 25 patients with tricuspid prostheses (11 mechanical and 14 biological); they were divided in 2 groups: group I: 14 patients without clinical evidence of malfunction and; group II: 11 patients with malfunction due to obstruction confirmed by catheterization, surgery and/or necropsy. The peak gradient was estimated by the modified Bernoulli equation and the prosthetic valve area by the pressure halftime method. RESULTS: the mean peak velocity in group I was 147 +/- 18 cm/sec versus 165 +/- 16 cm/sec (p NS) in group II. The mean pressure half-time in group I was 124 +/- 20 msec versus 355 +/- 48 msec (p less than 0.001) in group II. CONCLUSIONS: 1. A pressure half-time greater than 200 msec is very suggestive of malfunction due to obstruction (p less than 0.001). 2. There are normo-functioning tricuspid prostheses with prolonged pressure half-time, and the values that divides these groups from those with malfunction is small: 199 and 244 msec, that is why we suggest that every patient has to have his her own echocardiographic control in the immediate postoperative period.