Immune-mediated modulation of beta-adrenoceptor function in human dilated cardiomyopathy.
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Antigen-Antibody Reactions↗
Biomedical subjects
C Limas
Publications and source records attributed to C Limas.
Renal hydatid disease: diagnosis and treatment.
Four children with renal echinococcal cyst and associated liver involvement were treated in our clinic in the last 10 years. The diagnoses were suspected by ultrasonography and computed tomography and confirmed by the operative investigation that followed. One nephrectomy, one heminephrectomy and two cystectomies were performed. All children had uneventful recovery and they have not presented any recurrence so far. The value of the diagnostic modalities and the principles of the operative management are discussed.
Child↗
Gelatinolytic and caseinolytic proteinase activities in human prostatic secretions.
Seminal fluid contains a number of proteinase activities, many of which are secreted by the prostate gland. Our objective was to determine proteinase activities in human prostatic secretions which can degrade gelatin and/or casein. Prostatic secretions were collected by prostate massage from men with benign prostatic hyperplasia prior to surgery to relieve obstruction. Significant proteinase activities towards gelatin of about 81, 86, 94, 111, 115 and 163 Kd as well as less active forms of 23, 36, 38, 132, 137, and 148 Kd were detected using protein substrate-polyacrylamide gel zymography. In addition, Ca2+ stimulated activities of approximately 64, 66, 71 and 76 Kd; however, EDTA and EGTA inhibited all activities but the 23, 36 and 38 Kd forms (these were inhibited by benzamidine and epsilon-amino caproic acid). This suggests that the gelatinolytic activities of 64 Kd and greater were metalloproteinases and those of 23, 36, and 38 Kd were serine proteinases. Significant caseinolytic activities of 22, 25, 35, 37, 57, 90, 96, 102 and 116 Kd were found as well as several less active forms and a 12 Kd activity stimulated by Ca2+. Caseinolytic activities of 12, 14, 16, 96, 102, 116, and 126 Kd were inhibited by EDTA and EGTA indicating they are metalloproteinases. The 35, 37, 57 and 58 Kd caseinolytic activities were inhibited by benzamidine, and the 57 and 58 Kd forms by epsilon-aminocaproic acid suggesting they were serine proteinases. There was considerable variability among individuals in the molecular forms of proteinase activity expressed as well as the level of their activity. A significant decrease in the frequency of expression of the 132 Kd gelatinolytic activity was found in secretions from men with atypia or adenocarcinoma, as compared with men with benign prostatic hyperplasia alone. Our results show that human prostatic secretion contains a variety of proteinase activities. The expression of the 132 Kd gelatinolytic activity could prove useful in further evaluation of neoplastic prostatic disease.
Caseins↗
Proliferative activity of urothelial neoplasms: comparison of BrdU incorporation, Ki67 expression, and nucleolar organiser regions.
AIMS: To evaluate the proliferative activity of urothelial neoplasms, compare it with that of the normal urinary tract epithelium, and determine its relation to morphological grade and presence of invasion. METHODS: Multiple biopsy specimens from 53 individuals--eight normal controls, five patients with severe urothelial atypia, and 40 with transitional cell carcinomas (TCCs)--were studied using in vitro bromodeoxyuridine (BrdU) incorporation, Ki67 antigen expression, and quantitation of the nucleolar organiser regions (NORs). RESULTS: The percentage of nuclei labelled by BrdU (BrdU index) correlated well with the percentage of nuclei expressing the Ki67 antigen (Ki67 index). These proliferation indices were very low (less than 0.1% in 60% of samples) in the urothelium of normal controls and the morphologically unremarkable epithelium of patients with TCCs. Non-invasive TCCs had increased proliferation (BrdU index 6.32 (SD 0.8)%, Ki67 index 5.04 (0.6)% but lagged behind the invasive tumours (BrdU 20.9 (3.2)%, Ki67 18.6 (2.8)%). The average NOR count was 1.57 (0.03) in morphological normal epithelium, which increased progressively with grade in non-invasive TCCs, but varied greatly in invasive tumours and did not correlate with the proliferation indices. The spectrum of values for both proliferation indices and NORs was particularly wide in grade 2 TCCs. Severe atypias without exophytic growth had an increase in BrdU and Ki67 indices comparable with that found in grade 3-4 invasive TCCs; these also had the highest NORs per nucleus. CONCLUSIONS: The growth potential of urothelial neoplasms is an important indicator of their aggressive course. In particular, growth indices over 10% are strongly associated with the presence of invasion. Papillary grade 2 TCCs show heterogeneity in their growth characteristics which may relate to their diverse clinical course. The mitotic count underestimates the growth potential of papillary TCCs and the addition of proliferation indices such as BrdU incorporation or the Ki67 index may enhance the prognostic accuracy of conventional morphological grading.
Antigens, Neoplasm↗
Proliferative activity of normal and neoplastic urothelium and its relation to epidermal growth factor and transferrin receptors.
AIMS: To investigate the proliferative activity (given by the Ki67 index) of the normal, atypical, and neoplastic urothelium and its relation to the cellular reactivity for the epidermal growth factor (EGFr) and transferrin (Tfr) receptors. METHODS: The Ki67 index and the level of EGFr and Tfr reactivity were determined on frozen sections from 82 patients with urothelial cancer. Relevant clinical material was reviewed to establish correlations with the degree of atypia and invasion. RESULTS: Morphologically normal urothelium, whether derived from controls or patients with cancer, exhibited a low Ki67 index (less than 0.1%) and weak receptor reactivity. In transitional cell carcinomas (TCCs) the Ki67 index was increased: it ranged between 0.7% and 10% in non-invasive and exceeded 10% in 88% of the invasive TCCs. Strong positive reactions for EGFr were seen only in invasive TCCs, but in 47% of invasive TCCs the EGFr was not "overexpressed" and did not match the Ki67 index. A better correlation was found between the Ki67 index and the Tfr which was positive in 26% of the non-invasive and in 71% of the invasive tumours. All three variables were increased in severe atypia but varied considerably in lesser degrees of atypia. CONCLUSIONS: Despite the absence of a close correlation, accelerated growth and enhanced receptor expression were characteristic of invasive cancers. These results suggest that the growth rate in TCCs is not causally related to overexpression of growth factor receptors but that the latter is an abnormality which may accompany the malignant phenotype.
Carcinoma, Transitional Cell↗
Immune-mediated modulation of sarcoplasmic reticulum function in human dilated cardiomyopathy.
Calcium transport by the cardiac sarcoplasmic reticulum is depressed in human dilated cardiomyopathy, but the mechanisms involved are not clear. The possible involvement of immunological mechanisms was explored by evaluating the effect of sera from 49 patients with dilated cardiomyopathy on oxalate-facilitated Ca2+ uptake. In 14 of these patients, serum or IgG induced a time- and concentration-dependent decline (29 +/- 4% at 100-fold serum dilution) in Ca2+ transport. In 14 patients, autoantibodies against the beta 1-adrenoceptor were also demonstrated by a ligand binding inhibition assay. Serum from these patients inhibited the isoproterenol-mediated stimulation of Ca2+ uptake in permeabilized cardiac myocytes, but did not prevent the effect of protein kinase A. Anti-beta-receptor antibodies were present in 50% of the sera inhibiting Ca2+ uptake compared to 20% of those without inhibitory activity, (p less than 0.01). There was a strong correlation between the inhibition of sarcoplasmic reticulum Ca2+ transport and the HLA-DR4 phenotype (78% compared to 30% in patients with no inhibitory effect). These results suggest that immunological mechanisms play an important role in modifying sarcoplasmic reticulum function in about a third of the patients with detailed cardiomyopathy.
Adult↗
T-cell receptor gene polymorphisms in familial cardiomyopathy: correlation with anti-beta-receptor autoantibodies.
Cardiac autoantibodies have been detected in a significant proportion of patients with dilated cardiomyopathy, but their relation to the pathogenesis of the disease remains unknown. This issue was examined in 41 members of an Ohio family with a heritable disorder of the cardiac conduction system and the myocardium. In 41.5% of all members studied, serum anti-beta-receptor antibodies were identified by a combination of techniques: ligand binding inhibition assay, enzyme-linked immunoassay of a beta 1-receptor peptide, and adenylate cyclase inhibition. The prevalence of autoantibodies was significantly higher (p < 0.01) in the affected (64.7%) than in the unaffected (25.0%) members. A 10.0 kb restriction fragment length polymorphism of the C beta region of the T-cell receptor gene was also overrepresented in affected males (60% versus 30% unaffected males, p < 0.01). In males, the presence of anti-beta-receptor antibodies was linked to the 10.0 kb C beta polymorphism. In affected males, a BlgII C alpha 2.14 kb polymorphism was also more frequent (62% versus 32% in unaffected, p < 0.01) and was linked to the presence of anti-beta-receptor antibodies. The distribution of haplotypes defined by V beta 8, C alpha, and C beta probes was significantly different between affected and unaffected (p < 0.04) and between antibody-positive and antibody-negative individuals. Since the major function of the T-cell receptor is the recognition of processed autoantigens, these results provide additional support for the role of autoimmunity in dilated cardiomyopathy.
Adult↗
Assessment of immune modulation of beta-adrenergic pathways in human dilated cardiomyopathy: influence of methodologic factors.
Sera from patients with dilated cardiomyopathy contain autoantibodies modifying cardiac beta-adrenergic pathways. The influence of the methodology used to determine the prevalence of these antibodies was examined by comparing in 51 patients with idiopathic dilated cardiomyopathy the results of three assays: (1) isoproterenol-sensitive adenylate cyclase; (2) ligand binding inhibition; (3) enzyme-linked immunoassay (ELISA) of beta-receptor peptides. In 20% of the patients, all three tests gave positive results, while the concordance of the adenylate cyclase assay with either of the other two tests was 65%. ELISA was positive for a beta 1-receptor peptide corresponding to the second extracellular loop, but negative for a beta 2-receptor peptide. The results suggest that autoantibodies in dilated cardiomyopathy sera interact with several components of the beta-receptor-adenylate cyclase, and therefore a combination of methodologic approaches is needed to evaluate the prevalence and consequences of beta-receptor autoimmunity.
Adenylyl Cyclases↗
HLA-DR antigen linkage of anti-beta receptor antibodies in idiopathic dilated and ischaemic cardiomyopathy.
OBJECTIVE: Immunological mechanisms have been implicated in the pathogenesis of human dilated cardiomyopathy. The presence of autoantibodies against the beta 1 adrenoceptor in a substantial proportion of patients with dilated cardiomyopathy has been described and an association between the HLA-DR4 phenotype and anti-beta receptor antibodies has been identified. The objective of the present study was to examine whether the presence of such antibodies in ischaemic cardiomyopathy was limited to specific HLA-DR phenotypes. DESIGN: The HLA-DR dependence of anti-beta receptor antibodies detected by a ligand binding inhibition assay in patients with dilated cardiomyopathy (n = 68) was compared with that in patients with ischaemic cardiomyopathy (n = 73). RESULTS: 38% of the patients with dilated cardiomyopathy and 22% of those with ischaemic cardiomyopathy had serum anti-beta receptor antibodies. In dilated cardiomyopathy, the presence of anti-beta receptor antibodies was linked to the HLA-DR4 phenotype (that is, 50% of patients with this phenotype were antibody positive) whereas, in those with ischaemic cardiomyopathy HLA-DR1 was over-represented (that is, 37% of the patients with the HLA-DR1 phenotype were antibody positive compared with 17% of the HLA-DR1 negative patients). In both disease entities, the HLA-DR3 phenotype was virtually absent in the anti-beta receptor antibody group. CONCLUSIONS: These results suggest that the presence of anti-beta receptor antibodies is under immune genetic control that may depend on the nature of the underlying disease process.
Adult↗
Localization of type IV collagen in the basement membranes of human prostate and lymph nodes by immunoperoxidase and immunoalkaline phosphatase.
The object of these studies was to examine the localization of type IV collagen (Coll-IV) in the basement membranes (BM) of epithelial and stromal elements (smooth muscle, nerves, vessels) in normal, hyperplastic, and neoplastic (primary and metastatic) prostate. We also examined the relationship of Coll-IV distribution to the degree of tumor differentiation (Gleason grading system). We compared immunoperoxidase (IP) and immunoalkaline phosphatase (AP) techniques in these studies and in selected samples we also evaluated immunofluorescence (IF) localization of Coll-IV and the effects of tissue fixation and pepsin digestion. We found that IF localization of Coll-IV was intense in unfixed sections. IP and AP reactions were absent in fixed, paraffin-embedded sections but pepsin treatment yielded intense and uniform reaction products in these same preparations. Both the IP and AP techniques showed similar localization of Coll-IV in the BM of normal, hyperplastic, and well-differentiated tumor. In most of the higher-grade tumors Coll-IV localization was reduced and a similar pattern of distribution was observed after IP and AP techniques. However, in some high-grade tumors the IP technique showed good localization but AP did not, and vice versa. Such discrepancies were noted in the BM of the tumor cells, as well as in the BM of the stromal elements and in lymph nodes with metastatic tumor. Thus, our study shows decreased Coll-IV localization in higher-grade tumors and suggests that the use of a single technique (IP or AP) may exaggerate this apparent loss of Coll-IV BM components. The exact cause of these discrepancies is unknown but they must reflect variable losses in the ability of the tumor cells to form BM, degradation or decreased synthesis of BM components by high-grade tumors, or a combination of the above.
Adenocarcinoma↗
Effect of antireceptor antibodies in dilated cardiomyopathy on the cycling of cardiac beta receptors.
A substantial proportion of patients with dilated cardiomyopathy have circulating autoantibodies directed against the cardiac beta-adrenoceptor. These antireceptor antibodies inhibit both ligand binding to membrane beta-receptors and isoproterenol-sensitive adenylate cyclase. The functional consequences of antibody-receptor interactions were further studied by examining their influence on beta-adrenoceptor cycling. Sera from eight patients with cardiomyopathy induced a loss of beta-receptors from the surface of cardiac myocytes consistent with internalization. This loss was inhibited by concanavalin A, suggesting that receptor sequestration preceded internalization but was unaffected by the cytoskeleton inhibitors colchicine and cytochalasin. In cell-free preparations, serum-induced desensitization of beta-receptors was prevented by heparin but not the inhibitor of protein kinase A; this is consistent with a requirement for receptor phosphorylation by the beta-receptor kinase. In contrast to isoproterenol-mediated endocytosis, beta-receptors internalized under the influence of cardiomyopathic sera do not recycle to the plasma membrane. These results indicate that antireceptor antibodies in human dilated cardiomyopathy induced downregulation by interfering at several steps in the cycling of beta-receptors. These effects would contribute to the reported decline in beta-receptor responsiveness in cardiomyopathic myocardium.
Adult↗
Study of the clinical thermoluminescent dosimeter in the direct measurement of radiation adsorbed dose for radioimmunotherapy.
One of the major obstacles facing radioimmunotherapy (RIT) is the lack of a device to measure directly tumor and normal tissue radiation absorbed dose. Calculations based on the clearance and imaging scans have several limitations; hence we design and fabricate a sheathed clinical thermoluminescent dosimeter (TLD) for the measurement of absorbed dose by implantation in humans. Preclinical studies are performed in nine normal rabbits. Complete blood count, body temperature monitoring, clinical observation and necropsy show no untoward effects from the TLD. Consistent bone marrow radiation doses are noted in the four rabbits receiving 131I-labeled monoclonal antibody A6H. By using up to 20 clinical TLDs in one sheath, it will be possible to determine macroscopic heterogeneities in organs undergoing RIT.
Animals↗
Beta-adrenoceptor antibodies and genetics in dilated cardiomyopathy--an overview and review.
Autoantibodies against the cardiac beta-adrenoceptor are present in 30-40% of patients with idiopathic dilated cardiomyopathy and can be detected using ligand binding inhibition, immunoprecipitation or immunoblotting. The functional consequences of the antibody-receptor interactions are two-fold: (a) in isolated cardiac myocytes, diluted sera from cardiomyopathy patients induce internalization of the beta-receptors which are subsequently degraded intracellularly; (b) in membrane preparations, anti-receptor antibodies inhibit selectively the activity of isoproterenol-sensitive adenylate cyclase. The presence of anti-receptor antibodies is strongly linked to the HLA-DR4 phenotype: 72% of the HLA-DR4 patients in our series had anti-beta-receptor antibodies compared with 22% of the HLA-DR4-negative patients (most of which typed as HLA-DR1). Conversely, 67% of the antibody-positive patients typed as HLA-DR4, compared with only 10% of the antibody-negative patients. These results indicate the presence, in a subset of cardiomyopathy patients, of immunogenetical factors which may modulate myocardial beta-adrenoceptor function.
Autoantibodies↗
Ultrastructural localization of blood group antigen A in normal and neoplastic urothelium.
The subcellular distribution of the blood group antigen A in the transitional epithelium of the urinary tract and its neoplastic growths was studied using transmission immuno-electronmicroscopy. Sixty-five tissue specimens from 50 blood group A1 patients were processed according to an immunogold procedure which was optimized for preservation of both antigen and ultrastructure. The reactions were stronger in the glycocalyx of the luminal surfaces and at the interdigitating cytoplasmic processes of the cells. In the intracellular compartment the reactions were associated with tubulovesicular membrane-bound structures and with the Golgi complexes. Secretory products, intra- or extra-cellular, were also positive. The greatest variability was noted in the cell surface reactions, which were positive in 88% of normal but only 41% of neoplastic urothelial specimens. An inverse correlation was found between malignant behaviour and cell surface, but not intracellular, reactions. We conclude that, in transitional cell carcinomas, there is a quantitative defect in the processing of substance A which affects predominantly the cell surface component and may involve either the transport-insertion steps, the plasma membrane-associated glycosyltransferases or internalization of blood group antigen A.
ABO Blood-Group System↗
Quantitative interrelations of Lewis antigens in normal mucosa and transitional cell bladder carcinomas.
The factors regulating the expression of the Lewis blood group related antigens in tissues have yet to be clarified. In an attempt to resolve some of the existing controversies the quantitative interrelationship of the Le(a), Le(b), X and Y antigens in normal urothelium and transitional cell carcinomas (TCC) was studied using biopsy specimens derived from 22 patients whose ABO and Lewis red blood cell phenotype was known. A quantitative scale was devised to encompass both the extent and intensity of the immunohistochemical reactivity in one numerical value (score). The expression of these four antigens in the normal urothelium followed a characteristic pattern that is related to but not identical with the red blood cell phenotype. An excess of Le(b) and Y in the urothelium correlated with the Le(a-b+) red blood cell phenotype, while a relative increase in Le(a) and X (at the expense of Le(b) and Y) was associated with the Le(a+b-) red blood cell phenotype. This pattern can be accounted for by the combined effects of differential gene expression and substrate availability. The quantitative comparison of the antigenic make-up of TCCs with the corresponding normal tissue phenotype shows consistent trends, suggesting that the changes associated with neoplasia derive primarily from the suppression of specific gene products and, secondarily, from altered competitive substrate utilisation.
ABO Blood-Group System↗
Disparate effects of colchicine on thyroxine-induced cardiac hypertrophy and adrenoceptor changes.
Short-term (5 days) administration of L-thyroxine (0.1 mg/kg i.p. daily) to adult Sprague-Dawley rats induces a modest degree of cardiac hypertrophy (22% increase in heart weight/body weight ratios) and directionally opposite changes in cardiac adrenoceptors (24% increase in beta-adrenoceptors and 20% decline in alpha 1-adrenoceptors). Pretreatment with colchicine did not affect the ability of L-thyroxine to induce cardiac hypertrophy but prevented its effects on both beta- and alpha 1-adrenoceptors. These results suggest a selective involvement of microtubules in the action of thyroid hormones on the expression of cardiac adrenoceptor genes.
Animals↗
Relationship of epidermal growth factor receptor detectability with the A, B, H blood group antigens. Emphasis on normal and neoplastic urothelium.
The epidermal growth factor receptor (EGFR) is a glycoprotein that carries on its extracellular domains oligosaccharide chains, some of which are similar to blood group determinants. The author examined the expression of the EGFR using immunohistochemistry and three anti-EGFR antibodies with different fine specificities. These were applied to frozen sections from 120 tissue biopsies, including normal and neoplastic urothelium. The expression of blood group A, B, H determinants was also evaluated in the same tissues. Significant differences were noted, depending on the fine specificity of the anti-EGFR antibody, cellular differentiation, and the tissue donor's blood group. The most interesting finding was a reciprocal relationship between the reaction patterns obtained using antibodies with carbohydrate specificity and those with peptide specificity. These patterns were characteristic of cellular differentiation and suggested that the EGFR peptide determinants are detected in excess in immature and malignant cells that, however, appear deficient in oligosaccharide determinants. The combination of 'loss' of blood group antigen and an apparent overexpression of EGFR peptide determinants is indicative of invasive growth in transitional cell carcinomas.
ABO Blood-Group System↗
Anti-beta-receptor antibodies in human dilated cardiomyopathy and correlation with HLA-DR antigens.
The mechanisms responsible for the decline in the density of beta-adrenoceptors in the failing myocardium have not been adequately defined. It is a possibility that the nature of the process leading to heart failure may determine, in large part, the pathogenesis of this decline. Sera of some patients with dilated cardiomyopathy contain antibodies directed against the beta-adrenoceptor, as judged by ligand binding inhibition, immunoprecipitation and immunoblotting assays. Because deranged immune function is thought to play a role in dilated cardiomyopathy, immunogenetic markers of the propensity to develop anti-beta-receptor antibodies were sought. The prevalence of HLA-DR4 was significantly higher in dilated cardiomyopathy patients (40 vs 24% in 511 normal subjects, pc less than 0.001). In contrast, no association was found between HLA phenotypes and alcoholic cardiomyopathy. Furthermore, 72% (13 of 18) of the HLA-DR4 dilated cardiomyopathy patients had anti-beta-receptor antibodies compared to 22% (7 of 33) HLA-DR4-negative patients; in the latter, presence of antibody was linked to the HLA-DR1 phenotype. Conversely, 67% (15 of 23) of the antibody-positive patients were typed as HLA-DR4 compared to only 10% of the antibody-negative patients. Interestingly, none of the 23 antibody-positive patients were typed as HLA-DR3 while 37% of the antibody-negative did. Only 25% of alcoholic cardiomyopathy patients had anti-beta-receptor antibodies and no preponderant HLA association could be demonstrated. These results suggest that the presence of anti-beta-receptor antibodies in patients with idiopathic dilated cardiomyopathy may be under the control of the major histocompatibility locus.
Autoantibodies↗