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Biomedical subjects

J Fernandez

Publications and source records attributed to J Fernandez.

At least 163 records · Page 9Linked to original sources
PubMed1990

Tricuspid valve operations in 530 patients. Twenty-five-year assessment of early and late phase events.

From Jan. 1, 1961, through Dec. 31, 1987, 530 patients underwent an intracardiac operation that included a tricuspid valve procedure. The tricuspid valve was repaired in 351 patients (66%) and replaced in 179 (34%). Mean age was 56.9 years. Risk factors associated with tricuspid valve replacement included tricuspid stenosis (p = 0.02), jugular venous distention (p = 0.04), previous operation (p = 0.05), and angiographic severity of tricuspid valve incompetence (p less than 0.001). There were 78 hospital deaths (15%). Risk factors for hospital death included previous operation (p = 0.03), male gender (p = 0.03), hepatomegaly (p = 0.03), De Vega or Carpentier annuloplasty (repair group only), (p = 0.01), and older age at operation (p = 0.06). Ninety-eight percent of the patients were followed up. There were 185 late deaths (41%). The actuarial survival rate was 20% at 180 months. Risk factors for late death included male gender (p = 0.03), hepatomegaly (p = 0.04), and lack of postoperative warfarin therapy (p less than 0.001). Actuarial freedom from reoperation was 25.5% at 180 months. There was no difference in reoperation rates (p = 0.10) or survival (p = 0.42) whether the tricuspid valve had been repaired or replaced. We conclude that the requirement for surgical treatment of tricuspid valve insufficiency in patients with multivalvular disease constitutes a high risk group for cardiac surgery. Preoperative variables may predict the result of tricuspid valve replacement. Tricuspid valve replacement may be performed with the expectation of a low risk of valve-related events.

Aged↗
PubMed1989

Structural and idiotypic characterization of the L chains of human IgM autoantibodies with different specificities.

We have determined the V region amino acid sequence and/or serologic markers (kIIIb, PSL2, and PSL3) of 24 IgM monoclonal autoantibodies with specificities of anti-gamma-globulin (RF), anti-I (cold agglutinin), anti-low density lipoprotein and anti-intermediate filaments. The data emphasize the overwhelming selection of the HumKv325/VkIIIb L chain for this family of autoantibodies. The few amino acid substitutions found within the VL regions were mainly concentrated in the complementarity-determining region 1. JK and CK genes did not show the same pattern of restriction. There is a good correlation between the amino acid sequence and the presence of the kIIIb marker. The idiotypic marker PSL2 was present in 34 out of 35 kIIIb L chains analyzed (97%) and the PSL3 in 27 (80%). Moreover, the hydrophilicity and antigenic profiles of these L chains corroborate the presence of the epitopes detected by the anti-CRI. These results demonstrate a restricted selection of the Vk genes used by a family of self reacting proteins, and an unusual evolutionary conservation of the idiotypic structure that may be involved in the network regulation.

Agglutinins↗
PubMed1989

Cross-reactivity between penicillins and cephalosporins: clinical and immunologic studies.

Nineteen well-characterized penicillin-allergic patients were investigated for their sensitivity to cephalosporins containing potentially cross-reactive side chains. All patients were administered cephamandole parenterally and, if this was tolerated, a course of oral cephaloridine was administered. Only two patients responded to the cephamandole; none of the remaining patients reacted to cephaloridine. Benzylpenicilloyl RAST-inhibition studies with sera from three subjects who had not reacted to the cephalosporins demonstrated that cephamandole linked to proteins was capable of recognizing benzylpenicilloyl-specific IgE antibody. It is concluded that consideration of side chain structures can help to predict possible cross-reactions between penicillins and cephalosporins, but carefully controlled challenge tests are advisable before penicillin-allergic patients are treated with cephalosporins. In relation to cross-reacting potential, in vitro experimental studies are difficult to interpret and may in some circumstances overestimate the risk.

Adult↗
PubMed1989

Cavernous lymphohemangioendothelioma of the right atrium--a case report.

The authors report a successful resection of a rare cystic tumor in the right atrium, discovered in an asymptomatic patient with atrial fibrillation. The cystic nature of the tumor was characterized by two-dimensional echocardiogram preoperatively. The site of attachment and movement of the tumor were clearly shown by cine computed tomography preoperatively. The tumor contained numerous endothelium-lined cavernous channels and groups of red blood cells. These features are distinctly different from those of other cystic tumors.

Echocardiography↗
PubMed1989

Beta-2-microglobulin as the main component of primary amyloidosis located in the larynx.

A case of primary amyloidosis located in the larynx in which Beta-2-microglobulin (beta 2m) was the main component of the tissue is presented. Indirect immunofluorescence performed with monoclonal anti-human beta 2 m antibody (BBM1) showed a positive reaction, as did Congo red stain, and both patterns were similar. A significant increase in serum beta 2 m was observed; however, the clinical condition associated with this elevation remains unclear. We suggest that beta 2m is not only the main component of secondary amyloidosis in terminal nephropathy patients undergoing hemodialysis for prolonged periods, but that it could be part of the structure of other types of amyloid--either primary or secondary.

Adult↗
PubMed1988

Distinct patterns of heavy chain variable region subgroup use by human monoclonal autoantibodies of different specificity.

Using a panel of antibodies specific for H and L chain variable region subgroups, a panel of human monoclonal cold agglutinin (CA) and rheumatoid factor (RF) autoantibodies were analyzed. The vast majority of the two types of autoantibodies utilized VkIII L chains, many of which probably derive from the Humkv325 gene. However, while most RFs (77%) utilized VHI H chains, all the CAs used VHII subgroup H chains. These results are consistent with a model of autoantibody generation, wherein binding specificity is H chain defined in a set of antibodies that use a multipotential L chain.

Agglutinins↗
PubMed1988

Allergic reactions to vespids: comparison of sensitivities to two species in a Mediterranean area.

We have studied a group of twenty-seven patients who suffer allergic reactions to vespids stings. Specific IgE antibodies to venom extracts from Polistes gallicus and Vespula germanica were measured by RAST, and the crossreactivity between the two venoms was compared using the RAST inhibition technique. We concluded that, in southern Spain, sensitization to P. gallicus was more prevalent than that to V. germanica, with 44% of the subjects in this study reacting to P. gallicus compared with 33% to V. germanica. However, there was a considerable degree of crossreactivity between the two species. It is evident that Polistes is an important species in this area; however, both in Spain and other Mediterranean countries, V. germanica venom is used almost exclusively for diagnosis and immunotherapy.

Adolescent↗
PubMed1988

Anaphylaxis to amoxycillin but good tolerance for benzyl penicillin. In vivo and in vitro studies of specific IgE antibodies.

Three patients are reported on who suffered anaphylactic reactions after amoxycillin (AX) treatment and challenge but tolerated benzylpenicillin (BP) parenterally and orally. Two of the three patients had positive skin tests and RAST to AX reagents but negative responses to benzyl penicilloyl (BPO) specific skin tests and RAST and the minor determinant mixture (MDM) skin test reagent. The third case was negative to all skin tests and RAST. RAST and RAST inhibition on the two positive sera suggest that the response is related to the acyl side chain of AX.

Adult↗
PubMed1988

The radiology of cardiac valve prostheses.

The radiographic findings associated with the complications of valve implantation are presented. Complementary roles of echocardiography and cine fluoroscopy in the recognition of complications associated with this procedure are emphasized. Identification of prosthetic valves and the knowledge of the modes of action of the various types of valves are stressed.

Bioprosthesis↗
PubMed1988

Instantaneous risk of events following aortic valve replacement with pericardial valves: a ten-year experience.

Actuarial curves and linearized rates of occurrence are statistical functions that traditionally have been used to evaluate freedom from, or incidence of, valve-related events that occur as a result of aortic valve replacement (AVR); however, the instantaneous risk of an event can be more precisely pinpointed by the use of a time-related hazard function. This function was used to analyze 240 cases involving patients who underwent AVR with the Ionescu-Shiley bovine pericardial valve. Follow-up was for 10 years. The period from 60 to 70 months after implantation was apparently critical, since specific and cumulative events (intrinsic tissue failure, thromboembolism, prosthetic valve endocarditis, cumulated events, and death due to valve-related events) peaked during this period. We suspect important degenerative bioprosthetic changes take place during this period and are the cause, in part, for this pattern. In an effort to reduce the incidence of thromboembolism, close observation, and probably antiplatelet drug administration, should be initiated 60 months after implantation of this valve.

Journal Article↗
PubMed1987

Characterization and epitope mapping of a human monoclonal antibody reactive with the envelope glycoprotein of human immunodeficiency virus.

A human monoclonal antibody (IgG2, lambda), 1B8.env, was produced, reactive with the envelope glycoprotein of human immunodeficiency virus (HIV). The antibody specifically stains cells infected with HIV, as assessed by indirect immunofluorescence analysis and reacts with determinants displayed on the surface of infected cells. In Western blot analysis, the antibody reacts with bands of 160 and 41 kD, consistent with the precursor and transmembrane forms of the HIV envelope glycoprotein. The antibody also reacts specifically in immunofluorescence and Western blot analysis with cells infected with the recombinant vaccinia virus VSC-25, which contains the envelope gene of HIV. With the lambda gt11 expression vector, the epitope recognized by 1B8.env was mapped to a region of 11 amino acids in the coding region of gp41. This domain is highly conserved between several otherwise highly variable HIV isolates. In addition, this epitope appears to be recognized by the vast majority of HIV seropositive individuals. Although antibody IB8.env does not neutralize HIV virion infectivity or virally mediated cell fusion, the results presented here demonstrate the feasibility of generating and characterizing human monoclonal antibodies to HIV with these techniques. Additional antibodies produced in this manner will help to further characterize the humoral response to HIV infection, define biologically significant determinants on HIV proteins, and may be useful in clinical applications.

Amino Acid Sequence↗
PubMed1987

Intraplatelet levels of vWF:Ag and fibrinogen in myeloproliferative disorders.

Several platelet function abnormalities have been described in the myeloproliferative syndromes. We have measured the intraplatelet vWF:Ag and fibrinogen (FI) in the platelet lysates by Laurell technique in 11 patients with polycythemia vera (PV), 10 with essential thrombocythemia (ET), 14 with chronic myelocytic leukaemia (CML) and 3 with myelofibrosis (MF) and these results were correlated with platelet function abnormalities. Decreased intraplatelet levels of vWF:Ag and FI were found in all the patients with ET and MF, in 8 out of 11 PV and 3 out of 14 CML. A statistical significant correlation was observed between the intraplatelet levels of vWF:Ag and FI in the control group and in CML and PV, but no correlation was found in ET and MF. No correlation was observed between the plasmatic and the intraplatelet levels of vWF:Ag and FI in any group. Evidences of platelet activation (spontaneous platelet aggregation or circulating platelet aggregates) were observed in 40% of the cases with ET and PV, and all these cases had low intraplatelet levels of both antigens. None of the cases with MF had evidences of platelet activation and 2 out of 14 patients with CML had platelet activation. The deficiency of the dense bodies was less frequent than the depletion of the alpha granules (5 out of 11 PV, 4 out of 10 ET, 6 out of 14 CML and 2 out of 3 MF). The low intraplatelet contents of vWF: Ag and FI, more frequently observed in ET and PV, may be the result of platelet activation and in vivo release, but megakaryocyte dysfunction is more likely in myelofibrosis.

Antigens↗
PubMed1987

Antegrade and retrograde infusion of cardioplegia: assessment by thermovision.

The efficacy of two routes of cardioplegia infusion was examined by assessing the hypothermia induced in patients with critically obstructed or occluded major coronary arteries. The antegrade (through the aorta) and the retrograde (through the coronary sinus) methods of cardioplegia infusion were compared using myocardial thermograms. Patients (N = 8) were matched according to angiographic similarities of their coronary artery disease. Adequate myocardial cooling distal to a critical obstruction could frequently not be obtained with antegrade infusion of cardioplegic solution. With retrograde infusion, the desired uniform cooling of the myocardium, as determined by thermographic analysis of the surface temperatures of the heart, was obtained. We conclude that retrograde infusion of cardioplegic solution induces more effective and homogeneous hypothermia in patients with critically obstructive multivessel coronary disease, and may provide improved myocardial protection.

Angiography↗
PubMed1987

Diagnosis and management of traumatic ventricular septal defect.

Four cases of ventricular septal defect secondary to stab wounds of the heart are presented. One of three patients arriving at the Emergency Department in shock and who were resuscitated required an emergency thoracotomy. These patients had immediate repair of their external cardiac wounds in the Operating Room. Cases 1 and 3 developed heart failure and loud systolic murmur postoperatively. Case 4 was treated with chest tube for a left hemothorax and developed heart failure after discharge. In Cases 1, 2, and 3, 2-D echocardiography detected and located a VSD. In Case 3 Doppler measurement showed elevated RV pressure (45 mm Hg) and decreased peak tricuspid to mitral flow ratio (0.36, normal = 0.6). All patients underwent cardiac catheterization. In Case 4 there was associated mitral regurgitation. Cases 1 and 3 had pulmonary to systemic flow ratios greater than 3:1. Cases 1, 3, and 4 underwent operative repair. In Case 1 the VSD was closed with a dacron patch, and in Cases 3 and 4 it was sutured with Teflon pledgets. In Case 4 a puncture wound of the mitral valve annulus was simultaneously repaired. All patients are alive but in Case 1 postoperative 2-D echocardiography demonstrated partial dehiscence of the patch which has not required reoperation and in Case 3 post-repair 2-D echocardiography and Doppler flow studies have shown an intact VSD repair. This series of post-traumatic VSD demonstrates its varying clinical presentation and the diagnostic and followup benefits offered by 2-D echocardiography, especially when combined with Doppler flow measures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Causes of failure and pathologic findings in surgically removed Ionescu-Shiley standard bovine pericardial heart valve bioprostheses: emphasis on progressive structural deterioration.

Twenty-three Ionescu-Shiley standard bovine pericardial bioprostheses (15 aortic, seven mitral, and one tricuspid) removed at surgery from 21 adults, 28 to 75 years old (mean 55 at reoperation), were examined after functioning for as long as 84 months (mean 26). Reoperation was necessitated by active or healed endocarditis (10 valves), paravalvular leak (three), structural deterioration (eight), and other causes (two). Valves with degenerative dysfunction functioned 32 to 84 months (mean 68). Six had intrinsic cuspal calcification, one with stenosis, and there was regurgitation through secondary cuspal defects in five. Six valves had cuspal defects clearly associated with commissural sutures ("alignment stitches") unique to this valve design. One valve had a large basal cuspal tear. Other prominent pathologic features included gross cuspal thickening and mild stretching and microscopic deep fluid insudation, separation of collagen bundles, and mononuclear inflammation. Thus, structural disruption due to calcific tissue degeneration and design-related cuspal tears or commissural perforations are the predominant modes of degenerative failure of Ionescu-Shiley standard bovine pericardial valves.

Adult↗