PubMed Health⌕ Search

Biomedical subjects

R Babic

Publications and source records attributed to R Babic.

At least 19 recordsLinked to original sources
PubMed1997

An immunohistochemical assessment of cathepsin D in gastric carcinoma: its impact on clinical prognosis.

BACKGROUND: In the context of tumor-associated proteolysis, the prognostic value of cathepsin D in breast carcinoma has been studied but its role is controversial in relation to gastrointestinal carcinoma. The aim of the current study was to determine whether cathepsin D is a prognostic parameter for gastric carcinoma, and also to consider interaction with the urokinase-plasminogen activator (uPA) system as an established risk factor for tumor-associated proteolysis. METHODS: In a consecutive prospective series of 203 gastric carcinoma patients, expression of cathepsin D in tumor cells was semiquantitatively analyzed with immunohistochemistry (scored 0-3). Median follow-up time was 31 months (range, 9-56 months). Kaplan-Meier (log rank) and multivariate Cox analyses were used to analyze survival. RESULTS: Kaplan-Meier analysis (log rank statistics) revealed significant association of increasing cathepsin D detection with poorer disease free survival (P = 0.0042) and poorer overall survival (P = 0.0018) of curatively resected patients. Overall survival of all patients was not significantly correlated. Multivariate analysis of established risk factors for gastric carcinoma, including the uPA system, identified cathepsin D as a new and independent prognostic parameter for disease free survival (P = 0.020; relative risk, 2.98; 95% confidence interval, 1.28-6.91). Plasminogen activator inhibitor type-1 as a representative of the uPA system was confirmed as a strong independent factor for disease free and overall survival. Chi-square analysis showed significant correlation of higher cathepsin D levels with Laurén's diffuse-type carcinomas and strong evidence of uPA receptor in tumor cells. However, a subgroup analysis performed according to Laurén's classification revealed a univariate prognostic impact of cathepsin D on both diffuse and intestinal types without independent value. For patients with high levels of uPA receptor (scores of 2 and 3, n = 132), a highly significant association of increasing evidence of cathepsin D with disease free survival (P < 0.0001) and overall survival (P < 0.0001) was observed for curatively resected patients. Significant association with survival was also observed for all patients (P = 0.0407). CONCLUSIONS: Cathepsin D is a new functional prognostic parameter for gastric carcinoma patients with independent value for disease free survival. Moreover, this study indicates that consideration of more than one tumor-associated protease could lead to a more individualized estimation of risk for carcinoma patients.

Adult↗
PubMed1997

Urokinase plasminogen activator receptor (uPA-R): one potential characteristic of metastatic phenotypes in minimal residual tumor disease.

Evidence of dynamic development of cytokeratin (CK) 18-positive disseminated tumor cells in bone marrow of curatively resected cancer patients has implicated a subclinical minimal residual disease as a biologically relevant component in solid cancer. However, differentiation between irrelevant shed cells and those cells potentially capable of causing later recurrence has not yet been made. In parallel, accumulating data show functional association of the urokinase plasminogen activator (uPA) system and the membranous uPA receptor (uPA-R) with the capacity of a tumor cell for invasion and metastasis. The present study was designed to find descriptive evidence in vivo concerning whether uPA-R could be one potential characteristic for metastatically relevant phenotypes of disseminated tumor cells. An immunocytochemical double staining for uPA-R and CK18 (immunogold/alkaline phosphatase anti-alkaline phosphatase) was performed on perioperative and follow-up bone marrow aspirations of 78 curatively resected gastric cancer patients, if positive tumor cell status had been shown previously with the single alkaline phosphatase anti-alkaline phosphatase method. Bone marrow cells (10(6)) were examined in each assay. Postoperative qualitative and quantitative development of uPA-R-expressing disseminated tumor cells was followed in relation to uPA-R-negative cells and correlated with later clinical relapse. Double staining could be performed perioperatively or in follow-up, or both, in 58 of 78 patients. Expression of uPA-R on perioperatively disseminated tumor cells significantly correlated with later quantitative increases of tumor cells (P = 0.0009). Overall median tumor cell numbers with uPA-R expression significantly increased during follow-up from a median value of 5.5 to 10.0 in 10(6) cells (P = 0.008), and the mean relative percentage of uPA-R-positive, compared with uPA-R-negative, disseminated tumor cells also increased, from 47.9% at surgery to 68.6% in follow-up (P < 0.001). This was mainly due to patients with later tumor relapse (increase from 63.9 to 80.7%, P = 0.001). Patients without relapse showed slight increases at lower percentage levels (5.7% at surgery, 7.4% in follow-up). Differences for relapsing patients were significant (surgery, P = 0.006; follow-up, P < 0.001). Our results suggest from an in vivo model that uPA-R may be one antigen that enables identification and follow-up observations of metastatically relevant phenotypes of disseminated tumor cells, differentiating their individual potential for causing relapse.

Adult↗
PubMed1997

Coronary vasodilation without myocardial erection. Simultaneous haemodynamic, echocardiographic and arteriographic findings during adenosine and dipyridamole infusion.

AIM: The aim of this study was to evaluate simultaneously echocardiographic, haemodynamic and angiographic changes that occur during adenosine and dipyridamole infusion, in patients with one-vessel coronary artery stenosis. This would assess whether deterioration in left ventricular haemodynamics during vasodilator agent infusion is influenced by vasodilation per se, or the development of myocardial ischaemia. METHODS AND RESULTS: We performed adenosine (140 micrograms.kg-1.min-1 over 4 min) and dipyridamole (up to 0.84 mg.kg-1 over 10 min) stress echocardiography tests, together with angiographic and haemodynamic assessment, in 26 patients undergoing elective coronary angioplasty. In 12 of 26 patients, adenosine and dipyridamole tests were repeated 24 h after angioplasty. The criterion for echocardiography test positivity was the appearance of a new transient regional wall motion abnormality. Coronary angiograms were analysed with quantitative coronary arteriography. Adenosine and dipyridamole induced regional dysfunction in 18/26 (69%) and 14/26 (54%) patients before angioplasty, respectively (P = ns). In the echocardiography-positive patients, the percent diameter stenosis was significantly (P < 0.05) tighter stenosis than in the echocardiography-negative patients (adenosine, 66.6 +/- 8.3% vs 58.0 +/- 8.9%; dipyridamole, 69.2 +/- 7.1% vs 57.7 +/- 7.6%). During both tests, left ventricular end-diastolic pressure significantly increased (P < 0.05) in echocardiography-positive patients (adenosine, 9.8 +/- 2.7 mmHg to 13.5 +/- 4.1 mmHg; dipyridamole, 10.1 +/- 2.8 mmHg to 14.1 +/- 4.3 mmHg), but not in echocardiography-negative patients. In the patients who had undergone successful angioplasty (reduction to < 50% diameter stenosis), both adenosine and dipyridamole confirmed the arteriographic success of the procedure (echocardiography negative in all patients). In this group of patients, no significant change was observed in left ventricular end-diastolic pressure during adenosine or dipyridamole infusion. CONCLUSIONS: Intravenous infusion of either adenosine or dipyridamole was accompanied by an obvious increase in left ventricular end-diastolic pressure only in patients with induced wall motion abnormalities. Coronary vasodilation per se has no significant effect on left ventricular end-diastolic pressure when no ischaemia is induced, disproving any clinically significant 'erectile' and adverse effects of coronary vasodilation per se.

Adenosine↗
PubMed1997

Clinical value of extended biologic staging by bone marrow micrometastases and tumor-associated proteases in gastric cancer.

OBJECTIVE: To investigate whether extended staging, including biologic grading and aspects of an early systemic disease component, would give additional prognostic information on patients with curatively resected gastric cancer. BACKGROUND: Tumor-associated proteolytic mechanisms have been shown to be essential for invasion and metastasis. The urokinase-type plasminogen activator (uPA) system is of major biologic impact, but different interactive proteases and inhibitors with modulating effects also must be considered. The detection of early tumor cell dissemination indicates the systemic character of a primarily local gastric cancer. The confrontation of the organism with these cells determines the often unpredictable course of an individual tumor after presumed curative primary treatment. METHODS: In a prospective study of 247 consecutive patients with gastric cancer, detection of disseminated tumor cells in bone marrow aspirates was immunocytochemically performed in 180 patients. The expression of uPA, activators of uPA (cathepsin D, antithrombin III), uPA substrates (plasminogen, matrix-metalloproteinase 2 [collagenase IV, 72 kD; MMP-2]), uPA/plasmin inhibitors (plasminogen activator inhibitor type 1 and 2 [PAI-1, PAI-2], alpha1-antitrypsin, alpha2-antiplasmin), uPA receptor (uPA-R), and parameters of the uPA-R cycle (alpha2-macroglobulin, alpha1-antichymotrypsin) could be determined immunohistochemically and were scored semiquantitatively in 203 patients. Kaplan-Meier statistical techniques and multivariate Cox regression models were used for prognostic analyses. RESULTS: In multivariate analysis considering all the established risk factors, disease-free survival was independently predicted by PAI-1 (relative risk 2.21, 1.32-3.73) and cathepsin D (relative risk 2.98, 1.28-6.91) besides pT, pN, and extended resection. Tumor cell dissemination was found to be an additional prognostic factor in early tumor stages (pT1, T2) and lymphnode-negative patients. Stepwise regression analysis revealed an extended staging system with new risk groups. Node-positive, curatively resected pT1/2 patients with low expression of PAI-1 had a favorable prognosis (mean recurrence-free survival [MRT] 54.84 months), similar to that of node-negative patients (MRT 54.76 months). In node-negative, curatively resected pT1/2 patients, detection of bone marrow tumor cells and high expression of PAI-1 defined a subgroup with a steep decrease of prognosis (MRT 36.60 months), which was worse than that of node-positive patients (MRT 45.81). CONCLUSION: This new staging model gives better prognostic differentiation of subgroups, which should be considered in future adjuvant therapy protocols. In addition, it indicates that the uPA system might be a future therapeutic target.

Aged↗
PubMed1997

Immunocytochemical phenotyping of disseminated tumor cells in bone marrow by uPA receptor and CK18: investigation of sensitivity and specificity of an immunogold/alkaline phosphatase double staining protocol.

Phenotyping of cytokeratin (CK)18-positive cells in bone marrow is gaining increasing importance for future prognostic screening of carcinoma patients. Urokinase-type plasminogen activator receptor (uPA-R) is one example of a potential aggressive marker for those cells. However, a valid and reliable double staining method is needed. Using monoclonal antibodies against uPA-R and CK18, we modified an immunogold/alkaline phosphatase double staining protocol. UPA-R/CK18-positive tumor cell controls exhibited black uPA-R staining in 15-80% of cases and red CK18 staining in almost 100% of tumor cells. Isotype- and cross-matched controls were completely negative. Bone marrow from healthy donors was always CK18-negative. Reproducibility of CK18-positive cell detection was estimated in a series of specimens from 61 gastric cancer patients comparatively stained with the single alkaline phosphatase-anti-alkaline phosphatase (APAAP) and our double staining method (10(6) bone marrow cells/patient). In four cases, double staining could not reproduce CK18-positive cells. In 34 cases it revealed fewer or equal numbers, and in 23 cases more CK18-positive cells than the APAAP method. Overall quantitative analysis of detected cell numbers (838 in APAAP, range 1-280 in 10(6); double staining 808, range 0-253) demonstrated relative reproducibility of APAAP results by double staining of 97%. Correlation of results between both methods was significant (p < 0.001, linear regression). Sensitivity of double staining tested in logarithmic tumor cell dilutions was one CK18-positive cell in 300,000. Specific uPA-R staining was seen on CK18-positive cells in bone marrow from 29 of 61 patients, and also on single surrounding bone marrow cells. To test the specificity of this staining, bone marrow cytospins from 10 patients without tumor disease were stained for uPA-R with the APAAP method. uPA-R expression was confirmed in all 10 cases, with a mean of 6.5% uPA-R-positive cells in 1000 bone marrow cells (SEM 1.2%). These results suggest that our double staining protocol is a sensitive, reproducible, and specific method for routine uPA-R phenotyping of disseminated CK18-positive cells in bone marrow of carcinoma patients.

Alkaline Phosphatase↗
PubMed1996

High dose adenosine stress echocardiography for noninvasive detection of coronary artery disease.

OBJECTIVES: The aim of this study was to assess the tolerability and incremental diagnostic value of high adenosine doses in stress echocardiography testing in patients with coronary artery disease (CAD). BACKGROUND: In comparison with other pharmacologic stress echocardiography tests, standard dose adenosine stress has sub-optimal sensitivity for detecting milder forms of CAD. METHODS: Adenosine stress echocardiography was performed in 58 patients using a starting dose of 100 micrograms/kg body weight per min over 3 min followed by 140 micrograms/kg per min over 4 min (standard dose). If no new wall motion abnormality appeared, the dose was increased to 200 micrograms/kg per min over 4 min (high dose). All patients underwent coronary angiography. Significant CAD was defined as > or = 50% diameter stenosis in at least one major coronary artery. Thirty-three patients had one-vessel and seven had multivessel CAD. Coronary angiographic findings were normal in 18 patients. RESULTS: The high adenosine dose caused a slight but significant increase over baseline values in rate-pressure product. Limiting side effects occurred in two patients during the standard dose protocol and in one patient receiving the high dose regimen. The test was stopped in 30 patients after the standard adenosine dose regimen because of a provoked new wall motion abnormality. The sensitivity of adenosine echocardiography with the standard dose was 75% (95% confidence interval [CI] 63% to 87%). After completion of the standard dose protocol, 28 patients continued testing with the high dose adenosine protocol. The overall sensitivity of adenosine echocardiography, calculated as cumulative, increased to 92% (95% CI 84% to 100%) with the high dose (p < 0.05). The specificity of adenosine testing was 100% and 88%, respectively, with the standard and high dose regimen (p = 0.617). CONCLUSIONS: We believe that use of a higher than usual adenosine dose protocol for stress testing may improve the diagnostic value of adenosine echocardiography, mainly by increasing sensitivity in patients with single-vessel disease without deterioration of the safety profile and with only a mild reduction in specificity.

Adenosine↗
PubMed1996

The prognostic impact of the urokinase-type plasminogen activator system is associated with tumour differentiation in gastric cancer.

The prognostic value of tumour-associated proteolysis, especially the urokinase plasminogen activator (uPA) system, has been proposed in gastric cancer. In a prospective series of 203 resected patients, the expression of immunohistochemically assessed uPA, uPA-receptors and PAI-1 was strongly associated with survival. Multivariate analysis revealed PAI-1 as a new independent prognostic factor (overall survival: P = 0.005, relative risk 1.47, 95% CI 1.31-1.64). Gastric cancer is assumed to consist of two biologically different tumour types according to the histomorphological Lauren's classification. Consideration of this classification revealed strong prognostic impact of the uPA system in diffuse type cancers (overall survival: uPA, P = 0.028, relative risk 1.58, 95% CI 1.30-1.91; uPA-receptor, P = 0.001, relative risk 1.42, 95% CI 1.25-1.61) which are by definition low-differentiated (G3). For intestinal type cancers only in low-differentiated (G3) tumours a prognostic value was obtained (overall survival: PAI-1, P = 0.050, relative risk 2.16, 95% CI 1.17-3.96) while the association of grading and survival was not significant. This implies that the clinically relevant impact of the uPA system is associated with tumour differentiation.

Humans↗
PubMed1996

Prognostic significance of bone marrow micrometastases in patients with gastric cancer.

BACKGROUND: Monoclonal antibodies (mabs) against components of the cytoskeleton such as cytokeratins allow single disseminated epithelial carcinoma cells to be detected in the bone marrow. The aim of this study was to examine the prognostic relevance of these cells in patients with gastric cancer and to evaluate by multivariate analysis their predictive value compared with conventional risk factors. PATIENTS AND METHODS: A total of 1 x 10(6) cells from bone marrow aspirates were screened immunoctochemically for the presence and absolute number of disseminated tumor cells using mab CK2 to cytokeratin component no. 18. Patients were monitored prospectively for 30.6 +/- 15.2 months. RESULTS: Between one and 122 CK2-positive cells per 1 million mononuclear bone marrow cells were present in 95 of 180 patients (53%). A similar prevalence of 51% was found in curatively operated patients (55 of 109). Comparison with conventional prognostic risk factors showed a correlation of cell dissemination with pathohistologic tumor (pT) stage (P = .07) and Bormann classification (P = .022). Tumor-cell content in the bone marrow predicted disease-free and overall survival in curatively resected patients (P = .007 and P = .049, respectively). Multivariate analysis, which included established risk factors, showed that extent of tumor-cell dissemination was an independent prognostic parameter for disease-free survival in T1/2 tumors (P = .014; relative risk [RR], 1.84; 95% confidence interval [CI], 1.35 to 2.52), in intestinal type carcinomas according to Laurén (P = .008; RR, 1.62; 95% CI, 1.23 to 2.12), and in patients without lymph node involvement (P = .004; RR, 2.43; 95% CI, 1.22 to 4.82). CONCLUSION: Presence of disseminated tumor cells in bone marrow is indicative of systemic disease even in early-stage gastric cancer. The extent of tumor-cell presence in bone marrow correlates with prognosis in curatively resected patients. Therefore, a positive bone marrow finding may be a selection criteria for adjuvant treatment because of minimal residual tumor load.

Adult↗
PubMed1995

Expression of leukocyte cell adhesion molecules on gastric carcinomas: possible involvement of LFA-3 expression in the development of distant metastases.

Expression of the cell adhesion molecules ICAM-1 (CD54) and LFA-3 (CD58) was examined on primary gastric carcinomas, autologous benign mucosa and metastatic lesions. Although ICAM-1 was never observed on benign gastric epithelium, even in the presence of chronic inflammation and a strong leukocyte infiltrate, 38% (26/69) of the primary tumors expressed this molecule. ICAM-1 was restricted to differentiated tumors and correlated with the presence of leukocytes and the absence of vessel invasion. The ICAM-1 expression pattern of metastatic lesions reflected that of the primary tumor, suggesting that most tumors retain the non-inducible phenotype seen in normal mucosa while some become cytokine-sensitive. ICAM-1 expression showed no correlation with tumor relapse or survival. LFA-3 was absent from 8% (4/49) of the primary tumors and reduced (e.g., < or = 50% positive cells) in 33% (16/49). Expression of LFA-3 by more than 50% of the tumor cells correlated with cellular dedifferentiation (G3, G4), histologically detectable vessel invasion, tumor recurrence and decreased survival time. Primary tumors and metastases in draining lymph nodes demonstrated a broad range of LFA-3 expression. In contrast, distant metastases (liver and peritoneum) had uniformly high frequencies of LFA-3-positive cells, suggesting a selective advantage for these cells in the establishment of distant metastases.

Biomarkers, Tumor↗
PubMed1995

Individual development and uPA-receptor expression of disseminated tumour cells in bone marrow: a reference to early systemic disease in solid cancer.

It is unclear whether disseminated tumour cells detected in bone marrow in early stages of solid cancers indicate a subclinical systemic disease component determining the patient's fate or simply represent mainly irrelevant shed cells. Moreover, characteristics differentiating high and low metastatic potential of disseminated tumour cells are not defined. We performed repeated serial bone marrow biopsies during follow-up in operated gastric cancer patients. Most patients with later tumour relapse revealed either an increase or a constantly high number of tumour cells. In contrast, in patients without recurrence, either clearance of tumour cells or negative or low cell counts were seen. Urokinase plasminogen activator (uPA)-receptor expression on disseminated tumour cells was significantly correlated with increasing tumour cell counts and clinical prognosis. These results demonstrate a systemic component in early solid cancer, indicated by early systemically disseminated tumour cells, which may predict individual disease development.

Bone Marrow↗
PubMed1995

Tumor-associated proteolysis and prognosis: new functional risk factors in gastric cancer defined by the urokinase-type plasminogen activator system.

PURPOSE: The significance of tumor-associated proteolysis as reflected by parameters of the urokinase-type plasminogen activator (uPA) system for prognosis in cancer patients has been proposed because of evidence for its central role in basic mechanisms of invasion and metastasis. The aim of the present study was to evaluate whether the expression of the uPA parameters might be of clinical value in gastric cancer as a tumor/biologically defined risk factor. PATIENTS AND METHODS: In a consecutive series of 203 patients resected for primary gastric cancer, the expression of uPA, uPA-receptor (uPA-R), plasminogen activator inhibitor (PAI)-1, and PAI-2 was determined immunohistochemically. The results were classified semiquantitatively (0 to 3). Patients were followed-up prospectively for a median of 31 months (range, 9 to 56 months). Disease-free and overall survival were analyzed according to Kaplan-Meier and with univariate and multivariate Cox analyses in relation to conventional prognostic factors. RESULTS: Univariate analyses revealed a highly significant inverse correlation of uPA, uPA-R, and PAI-1 expression with survival time (P = .0008, P = .0002, and P = .0002, respectively), whereas PAI-2 demonstrated only a weak correlation. In multivariate analyses, PAI-1 was an independent and strong prognostic factor (P = .005; relative risk, 1.47 per staining degree; 95% confidence interval [CI], 1.31 to 1.64). In pT1/2 tumors and in Laurén's diffuse and mixed types, uPA, uPA-R, and PAI-1 added significant prognostic information. PAI-1 was also associated with survival in the subgroup of lymph node-positive patients. CONCLUSION: PAI-1, uPA, and uPA-R are new functional risk factors reflecting clinical prognosis. In particular, PAI-1 is a new independent variable for the identification of patients at high risk after tumor resection. Our results support the hypothesis that the uPA system probably is of general importance for prognosis of patients with malignant disease, indicating an individual tumor's capacity for invasion and metastasis.

Adult↗
PubMed1994

Immunohistological studies of complement activation after xenogeneic perfusion of a working heart model.

Transplantation of organs from one species to another leads to immediate hyperacute rejection. Activation of complement is one important factor involved in this process. Whether complement activation is induced by preformed natural antibodies (PNAbs) via the classical pathway or by an "activator surface" via the alternative pathway is unclear. In order to simulate the relevant clinical situation of animal donor/human recipient we perfused working porcine hearts ex vivo with human blood. This also offered the possibility to study the process of complement activation in a precisely defined system with human complement proteins. PNAb titer and complement lytic activity of the plasma were measured. Immunohistological stainings for IgG, IgM, C1q, C4, C3d, C5-9, factor B, and properdin were performed on tissue sections of the left ventricle. PNAb titer almost totally disappeared within the first 5 min of perfusion. Complement lytic activity of the classical pathway decreased similarly within the first 3 h of xenogeneic and autologous perfusion from 70% to 40%. More detailed immunohistological studies revealed positive staining for C3d on endothelium and myocardium of ex vivo perfused xenogeneic hearts. Complement-induced cytotoxicity was proven by the presence of C5-9 (membrane attack complex). However, hardly any C1q and C4 could be found in the ex vivo xenogeneic perfused hearts. Staining for factor B was positive and proved activation via the alternative pathway. Beyond that, the presence of properdin binding even indicated an upregulation of the alternative pathway C3 convertase.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Dipyridamole-dobutamine echocardiography: a novel test for the detection of milder forms of coronary artery disease.

OBJECTIVES: This study was designed to assess the clinical, hemodynamic and diagnostic effects of the addition of dobutamine to dipyridamole echocardiography. BACKGROUND: Pharmacologic stress echocardiography with either dipyridamole or dobutamine has gained acceptance because of its safety, feasibility, diagnostic accuracy and prognostic power. The main limitation of the two tests is a less than ideal sensitivity in some patient subsets, such as those with limited coronary artery disease. We hypothesized that two pharmacologic stresses might act synergistically in the induction of ischemia by combining the mechanisms of inappropriate coronary vasodilation (with dipyridamole) and an increase in myocardial oxygen consumption (with dobutamine). METHODS: One hundred fifty patients (mean [+/- SD] age 51 +/- 11 years) referred for stress echocardiography were initially studied by dipyridamole-dobutamine echocardiography. The test was stopped during the dipyridamole step in 95 patients for achievement of a predetermined end point (obvious dyssynergy induced by lower or higher dipyridamole dose), and dipyridamole-dobutamine tests were performed in 55 patients (negative dipyridamole echocardiographic test). In the same 150 patients the dobutamine echocardiographic test (up to 40 micrograms/kg body weight per min) was performed on a separate day. RESULTS: Significant coronary artery disease (> 50% diameter stenosis of at least one major coronary vessel by quantitative coronary arteriography) was present in 131 patients (one vessel in 115; two vessels in 10, three vessels in 6), with normal coronary arteriography in 19. The feasibility of the dipyridamole-dobutamine test was 96%. Self-limiting side effects occurred in 5% of patients. The peak rate-pressure product was lowest during the dipyridamole test (132 +/- 30) and was comparable during the dobutamine (186 +/- 59) and dipyridamole-dobutamine tests (179 +/- 45, p = NS vs. dobutamine; p < 0.01 vs. dipyridamole). Sensitivity was 71% for dipyridamole, 75% for dobutamine and 92% for dipyridamole-dobutamine echocardiography (dipyridamole vs. dipyridamole-dobutamine, p < 0.01; dobutamine vs. dipyridamole-dobutamine, p < 0.01; dipyridamole vs. dobutamine, p = NS), whereas specificity was 89% for dipyridamole, 79% for dobutamine and 89% for dipyridamole-dobutamine echocardiography (p = NS for all). CONCLUSIONS: Routine dobutamine addition to dipyridamole stress testing is clinically useful and well tolerated. It expands the spectrum of the disease detectable by pharmacologic stress echocardiography and allows documentation of milder forms of coronary artery disease that can be missed by conventional dipyridamole or dobutamine stress echocardiography.

Adult↗
PubMed1994

Integrity and viability of homograft valves.

Since it has been suggested that the leaflet tissue viability influences durability after homologous valve replacement, we compared different harvest and preservation techniques in order to examine the quality and smoothness of homograft conservation. We analyzed human aortic and pulmonary valve leaflets obtained from 'heart-beating donors' (HBD) during heart transplantation and from 'non-heart-beating donors' (NHBD) during coroner's autopsies. Valves were either cryopreserved in liquid nitrogen or stored at 4 degrees C in nutrient medium similar to the procedure reported in our protocols of the homograft bank system. All grafts from NHBD had been antibiotically sterilized for 3 days beforehand. Morphological observations were made using light and electron microscopy and, in order to characterize the endothelial cell viability, a non-radioactive cell proliferation assay was used. The PGI2 secretion of the remaining endothelium was defined as the 6-keto-prostaglandin F1 alpha metabolite by an enzyme immunoassay. Observations in the scanning electron microscope revealed that, after cryopreservation, homografts show an almost confluent endothelium when processed within 24 h after harvest from HBD, but lack endothelial cells when obtained from NHBD. Cryopreserved grafts from NHBD exhibited an altered tissue structure with edema and vacuolization within the spongiosa of the leaflets as well as irreversible cell damage when examined under the light and transmission electron microscope. That the metabolic activity of HBD homografts was maintained was confirmed by proven PGI2 secretion (6150 +/- 1200 pg/3 ml M199 after cryopreservation), whereas specimens from NHBD showed a reduced (1950 +/- 730 pg/3 ml M199) and, after cryopreservation, almost no release (P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

The contribution of endothelial cells to hyperacute rejection in xenogeneic perfused working hearts.

The mechanisms leading to the hyperacute rejection of a vascularized xenograft are still incompletely understood. The first stage of the rejection process is when blood of the recipient comes into contact with the endothelium of the xenograft. A working heart model was used to examine endothelium-related processes and their impact on organ function. Pig hearts were perfused with porcine (autologous) or human (xenogeneic) blood. Cardiac function was evaluated by calculating the stroke work index, arteriovenous oxygen, coronary flow, and resistance. PgF1a as a marker of endothelial activation, its antagonist TXB2, and myoglobin reflecting myocardial damage were measured in the hemoperfusate. H&E and PAS staining and immunohistological demonstration of factor VIII-related antigen was performed. Xenogeneic perfused porcine hearts showed significantly less stroke work, a higher arteriovenous oxygen difference, and an increased coronary resistance. Factor VIII-related antigen could not be demonstrated immunohistologically on the endothelium after xenogeneic perfusion. PgF1a levels were significantly higher in the xenogeneic hemoperfusate, indicating endothelial cell activation. The concentration of myoglobin in the hemoperfusate remained within normal values and was similar during autologous and xenogeneic perfusion. Therefore endothelium-related processes are likely to affect the coronary circulation--thus being one mechanism leading to diminished cardiac performance during hyperacute rejection.

Acute Disease↗
PubMed1993

[Teratoma of the umbilical cord. Case report with literature review].

A rare case of teratoma of the umbilical cord is reported. It is differentiated from acardius amorphus and compared with the nine cases reported in the literature since the first description in 1878. The clinical consequences for pregnancy of the tumour's influence on the circulation are discussed. For the first time, non-radioactive in situ hybridization of the interphase nucleus was performed in a teratoma of the umbilical cord. The results are presented and different histogenetic pathways, e.g. parthenogenetic origin of the teratoma, are debated.

Cell Transformation, Neoplastic↗