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Biomedical subjects

C E Essed

Publications and source records attributed to C E Essed.

At least 19 recordsLinked to original sources
PubMed1998

Polychlorinated biphenyls in adipose tissue, liver, and brain from nine stillborns of varying gestational ages.

We analyzed polychlorinated biphenyls (PCBs) in s.c. adipose tissue, liver, and brain of nine fetuses who died in utero. Their median (range) gestational ages and birth weights were 34 (17-40) wk and 2050 (162-3225) g. Three fetuses were small for gestational age. The levels of PCB congener nos. 118, 138, 153, and 180, and the sum of these (sigmaPCB), were calculated in terms of tissue total fat content (ng/g fat). The median (range) sigmaPCB (in ng/g fat) amounted to adipose tissue 235 (97-768), liver 198 (67-362), and brain 50 (22-122). Median (range) sigmaPCB levels in liver and brain were 0.8 (0.4-0.9) and 0.2 (0.1-0.3) times, respectively, as high as the sigmaPCB levels in adipose tissue. There were strong relations between sigmaPCB in adipose tissue and sigmaPCB in liver (r=0.98; p < 0.01), and between sigmaPCB in adipose tissue and sigmaPCB in brain (r=0.91; p < 0.01). Adipose tissue, liver, and brain did not show differences in the distribution of congeners 118, 138, 153, and 180, and there was no statistically significant association between tissue PCB levels and gestational age (r varied between 0.22 and 0.47). Median sigmaPCB levels in fetal adipose tissue proved to be comparable with our previously established sigmaPCB levels in mature breast milk of 93 Dutch women (median 414; range 158-969 ng/g of fat). The PCB congeneric distribution of fetal adipose tissue was not different from that of human milk. We conclude that maternal PCBs have a tendency to accumulate notably in fetal tissues with high triglyceride contents. They are easily transferred across the placenta and seem to become equilibrated among the apolar parts of maternal and fetal lipids.

Adipose Tissue↗
PubMed1994

Fluorescence in situ hybridisation on formalin fixed fetal tissue in the diagnosis of chromosomal syndromes.

Two cases of stillborn children with multiple congenital anomalies are presented. No routine karyotyping was performed. After dysmorphologic evaluation a tentative diagnosis of trisomy 18 and triploidy, respectively, could be made. Fluorescence in situ hybridisation with several chromosome specific probes on formalin fixed paraffin embedded tissue confirmed the suspected diagnosis in both cases. In view of the important consequences for the parents (relatively low recurrence risk, availability of prenatal diagnosis in subsequent pregnancies) fluorescence in situ hybridisation for the common chromosomal aneuploidies should be performed in selected cases of stillborn fetuses with multiple congenital malformations.

Abnormalities, Multiple↗
PubMed1992

Electrical impedance of layered atherosclerotic plaques on human aortas.

Electrical impedance measurements were performed on 13 atherosclerotic human aortic segments at 67 measuring spots in order to determine whether or not on the basis of these data a distinction can be made between atherosclerotic lesions and normal tissue. Stenosis localization and guidance of interventional techniques could be among the applications of an impedance measuring technique implemented on a catheter system. The experimental results, obtained with a two-electrode measuring technique, show that the apparent resistivity of an atherosclerotic spot does not necessarily deviate much from the resistivity of normal tissue. This is clarified by histology which shows that the majority of lesions has a surface layer of connective, fibrous tissue having almost similar conducting properties as the normal arterial wall. For gaining a deeper understanding of the way in which the measured data come about, a physical model of an atherosclerotic lesion is presented and confronted with the data. Both experimental data and theoretical considerations lead to the conclusion that only when the superficial fibrous layer is absent or very thin in relation to the size of the measuring electrode, the measured resistivity at a lesion is much higher than at normal spots. This occurs as a consequence of the high ohmic properties of the calcified or lipid deposits in the atherosclerotic lesion.

Aortic Diseases↗
PubMed1992

Histological changes in the aortic valve after balloon dilatation: evidence for a delayed healing process.

OBJECTIVE: To investigate whether balloon dilatation of the aortic valve induces long-term macroscopic or histological changes or both to explain the restenosis process. DESIGN: Prospective study of 39 consecutive patients. Sixteen later (mean (SD) 12 (10) months) required operation. This non-randomised subgroup was compared with 10 patients who had aortic valve replacement without prior dilatation. SETTING: University cardiology and cardiac surgery centre and pathology department. PATIENTS: 16 patients who had aortic valve replacement because of failure of or restenosis after balloon dilatation of the aortic valve. Twelve resected valves were examined. INTERVENTIONS: Percutaneous balloon dilatation of the aortic valve (maximal balloon size: trefoil 3 x 12 mm balloon or bifoil 2 x 19 mm balloon) and surgical inspection before excision of the aortic valve leaflets during open-chest aortic valve replacement. Fixation, decalcification, and staining for histology. MAIN OUTCOME MEASURES: Presence of long-term pathological changes in the resected valve and their relation to restenosis after balloon dilatation. RESULTS: Macroscopically the previously dilated valves were indistinguishable from valves from the patients who had valve replacement only. Microscopically, the dilated aortic valves showed areas of young scar tissue that were not seen in a control group of surgically excised stenotic aortic valves. This persistent scarring reaction was seen around small tears or lacerations of the collagenous valve stroma, fractures in calcified areas, and splits in commissures. Young scar tissue without collagenisation was still present 24 months after dilatation. CONCLUSION: Organisation and collagenisation of scar tissue develops slowly after balloon dilatation of the aortic valve. This prolonged scarring reaction may explain the late development of restenosis in some patients.

Aged↗
PubMed1991

Alloreactive lymphoid infiltrates in human heart transplants. Loss of class II-directed cytotoxicity more than 3 months after transplantation.

From 535 endomyocardial biopsies (87 heart transplant recipients) 283 cell cultures could be generated. All cultures tested contained T lymphocytes and in most cases CD4 was the predominant phenotype at any time posttransplant. A significantly higher proportion of CD8-dominated cultures was found among cultures from biopsies without myocytolysis. In the first 3 months post transplant 57% of cultures showed cytotoxicity against both class I and class II mismatched donor major histocompatibility complex (MHC) antigens, changing to an incidence of 33% at greater than 90 days. This proved to be due to a significant decrease in the number of cultures with human leukocyte antigen class II-directed cytotoxicity. This study shows that early after transplantation a heart transplant is infiltrated with activated donor-specific cytotoxic T cells which recognize a broad spectrum of mismatched donor MHC antigens, and that in time this spectrum becomes more restricted.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1991

Chronic non-ischaemic congestive heart disease and endomyocardial biopsies. Worth the extra?

The diagnostic yield of endomyocardial biopsies in patients with chronic congestive heart failure of non-ischaemic aetiology remains questionable and, therefore, the use of endomyocardial biopsies under such circumstances is at stake. The present report documents the correlation between the histologic interpretation of endomyocardial biopsies and the corresponding cardiac explants in 13 patients who underwent cardiac transplantation. The biopsy diagnoses in these patients varied from 'compatible with dilated cardiomyopathy' (n = 6) to 'non-conclusive' (n = 4), 'ischaemia' (n = 2) and 'borderline myocarditis' (n = 1). Correlation with the corresponding cardiac explants revealed hypertrophy of myocytes as the leading histologic feature in the majority of cases. Because of the non-specific histopathology of dilated cardiomyopathy, the discrepancy between biopsy diagnoses and the leading explant diagnosis is mostly a matter of semantics. Ischaemia was present at high incidence, but is considered a result of imparied myocardial perfusion rather than the prime mechanism of heart failure. In four cardiac explants myocarditis was encountered, while the corresponding biopsies showed no cellular inflammation. In two, the cellular infiltrates suggested an early state of repair. One heart contained an active and extensive lymphocytic myocarditis. The fourth case showed an eosinophilic myocarditis, most likely acquired after the biopsy was taken. These discrepancies almost certainly relate to the sampling error and the time interval between biopsy and onset of symptoms. The immediate diagnostic yield of the biopsy, in this particular subset of patients, was minimal, particularly with respect to the diagnosis 'myocarditis'. Nevertheless, biopsy diagnoses such as 'compatible with' and 'non-conclusive' do contribute to the final categorization and management of these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Aortic valvuloplasty of calcific aortic stenosis with monofoil and trefoil balloon catheters: practical considerations. An evaluation of balloon design and valvular morphology relationship, derived from experimental and clinicopathological observations.

In order to evaluate the relation between balloon design (monofoil, trefoil) and valvular configuration, experimental aortic valvuloplasty was performed in four post-mortem hearts with calcific aortic stenosis of various morphology. The degree of obstruction of the aortic orifice was assessed by computed axial tomography during inflation of monofoil 15 and 19 mm and trefoil 3 x 12 mm balloon catheters. We also evaluated the hemodynamic repercussion of balloon inflation (fall in systolic aortic pressure) in four elderly patients with acquired aortic stenosis who underwent a percutaneous transluminal aortic balloon valvuloplasty, with stepwise increasing balloon sizes of 15 mm, 19 mm and 3 x 12 mm, as during our in vitro experiments, and who underwent aortic valve replacement later on. In these patients, we correlated the anatomy of the excised aortic valves with the retrospective analysis of aortic pressure curves recorded during previous valvuloplasty procedures. Our experimental and clinicopathological observations showed that the degree of obstruction of the aortic orifice in post-mortem specimens and the tolerance to balloon inflation in live patients are dependent of the valvular configuration. Although trefoil balloons have the theoretical advantage to avoid complete obstruction of the aortic orifice during inflation, we observed that in presence of a tricuspid configuration, they could be potentially more occlusive than monofoil balloons since each of the 3 individual components of the trefoil balloon occupied the intercommissural spaces while inflated. However, they offered more residual free space when inflated in aortic valves with a bicuspid configuration (i.e. congenitally bicuspid valves or tricuspid valves with one fused commissure). In our opinion, these observations are relevant, since degenerative disease of the aortic valve (i.e. tricuspid valve without commissural fusion) is now recognized as the most common etiology of aortic stenosis in the elderly.

Aged↗
PubMed1990

Juxtaductal pulmonary artery coarctation. An underestimated cause of branch pulmonary artery stenosis in patients with pulmonary atresia or stenosis and a ventricular septal defect.

An angiographic and clinical study was performed to establish the prevalence of juxtaductal pulmonary artery coarctations in patients with pulmonary atresia or stenosis and a ventricular septal defect or a complex intracardiac defect. The present study is an adjunct to a previously reported portmortem study, in which the incidence of these pulmonary artery coarctations was found to be unexpectedly high. Pulmonary artery coarctations were identified angiographically in 10 of the 15 patients with pulmonary atresia. One additional patient had a bilateral ductus arteriosus and confluent pulmonary arteries, but did not have a pulmonary artery coarctation. Pulmonary artery coarctations were much less prevalent in the cases with pulmonary stenosis (5/50). However, these pulmonary artery coarctations appeared identical to those of the cases with pulmonary atresia. Fourteen pulmonary artery coarctations were located in the pulmonary artery at the side of the ductus arteriosus; this was left sided in 12 and right sided in two patients. In one patient the side of the ductus could not be established. The types and the locations of the pulmonary artery coarctations in the present study were identical to those in the previous postmortem study. Ductal tissue was found in many of the pulmonary artery coarctations of the postmortem study and is likely to be present in the clinical cases as well. The majority of the angiographically identified pulmonary artery coarctations were subsequently confirmed at operation or at autopsy. The clinical outcome and follow-up of the patients is discussed, and it is concluded that juxtaductal pulmonary artery coarctations should be specifically looked for before and during any type of surgical intervention in these patients.

Constriction, Pathologic↗
PubMed1989

Intravascular echographic assessment of vessel wall characteristics: a correlation with histology.

In vivo application of intravascular high frequency ultrasonic imaging for peripheral and coronary artery disease is a promising technique for vascular surgeons, radiologists and cardiologists. This report demonstrates in vitro results obtained with a high frequency imaging catheter (40 MHz) in 70 human specimens including arteries with and without atherosclerosis, veins, coronary artery bypass grafts and vascular prosthetic material. Correlation between the ultrasonic images and the histologic characteristics of the corresponding vessel wall tissue and lumen geometry was established. In addition, the effect of intervention techniques i.e. balloon angioplasty, spark erosion and laser were studied with ultrasound and histology. It is anticipated that development of such a catheter imaging technique has potential for diagnostic imaging and for combination with therapeutic systems.

Angioplasty, Balloon↗
PubMed1989

Does platelet aggregation play a role in the reduction in localized intimal proliferation in normolipidemic pigs with fixed coronary artery stenosis fed dietary fish oil?

In order to investigate the effect of fish oil on intimal proliferation of coronary arteries with a fixed stenosis normolipidemic piglets received a basic diet to which either 9% (w/w) lard (L, n = 8) or 4.5% (w/w) lard and 4.5% (w/w) mackerel oil (ML, n = 8) was added for 4 months. Stenosis was applied by implanting a 4.0 X 2.0 mm (i.d.) Teflon constrictor around the left anterior descending coronary artery (LADCA) (o.d. 2.7 +/- 0.1 mm). During the dietary period ADP-induced platelet aggregation in whole blood was higher in L than in ML. Partial replacement of 20:4 n - 6 by 20:5 n - 3 fatty acids in the platelet membranes of ML may have altered platelet aggregation by changes in eicosanoid synthesis. The plasma cholesterol and triglyceride levels did not change in L, but decreased in ML. At the end of the 4-month dietary period the animals were again anesthetized and regional myocardial perfusion (radioactive labelled microspheres) and systolic segment length shortening (SLS) were measured while the hearts were paced at 160 pulses/min. Perfusion and SLS of non-LADCA nourished segment were similar for L and ML. However, transmural flow to the LADCA perfused myocardium was impaired in both groups, but the deficiency in endocardial perfusion was considerably larger in L than in ML, resulting in a larger loss of SLS in the former. Remote (2-3 cm from the site of the constrictor) luminal encroachment was minimal (less than 2%) in both groups, but at the site of the constrictor there was significant encroachment in both groups which was higher in L (62 +/- 7%) than in ML (11 +/- 4%). It is thought that in these normolipidemic pigs the reduction in platelet aggregation may play a role in the smaller intimal proliferation of the fish oil-fed animals.

Animals↗
PubMed1989

Arterial wall characteristics determined by intravascular ultrasound imaging: an in vitro study.

The feasibility of assessing arterial wall configuration with an intravascular 40 MHz ultrasound imaging device was investigated in an in vitro study of 11 autopsy specimens of human arteries. The system consists of a single element transducer, rotated with a motor mounted on an 8F catheter tip. Cross sections obtained with ultrasound were matched with the corresponding histologic sections. The arterial specimens were histologically classified as of the muscular or elastic type. Muscular arteries interrogated with ultrasound presented with a hypoechoic media, coinciding with the smooth muscle cells. In contrast, the media of an elastic artery densely packed with elastin fibers was as echogenic as the intima and the adventitia. On the basis of the cross-sectional image, it was possible to determine the nature of the atherosclerotic plaque. The location and thickness of the lesion measured from the histologic sections correlated well with the data derived from the corresponding ultrasound images. This study indicates that characterization of the type of artery and detection of arterial wall disease are possible with use of an intravascular ultrasound imaging technique.

Adult↗
PubMed1989

Intravascular ultrasonic imaging: histologic and echographic correlation.

The feasibility of assessing arterial wall characteristics with an intravascular 40 MHz ultrasonic imaging device was determined in vitro. Ten autopsy specimens of human arteries, with and without atherosclerosis, were studied. A close relationship was observed between the histologic section and the corresponding ultrasonic cross-section with regard to the location, maximum plaque thickness and extent of the atherosclerotic lesion along the circumference of the vessel wall. Based on echogenicity of the atherosclerotic lesion, ultrasound could distinguish four basic types of atherosclerotic plaque components: 1. hypoechoic: a reflection of lipid deposits; 2. soft echoes: reflective of fibromuscular tissue; 3. bright echoes: representative of fibrous tissue; 4. bright echoes with shadowing behind the lesion: representative of calcium deposits. It is anticipated that development of such a catheter-tip imaging system combined with recanalisation methods will be of immense benefit for the precise localisation and identification of vessel wall pathology, precise positioning of a recanalisation instrument (laser device, atherectomy catheter) and subsequent use of this recanalisation procedure and for assessing the effect of recanalisation.

Adult↗
PubMed1989

Indirect enzyme-linked immunosorbent assay for immunoglobulin G and four immunoassays for immunoglobulin M to Toxoplasma gondii in a series of heart transplant recipients.

Toxoplasma gondii infections in heart transplant recipients were monitored by indirect enzyme-linked immunosorbent assay for immunoglobulin G (ELISA-IgG), indirect ELISA-IgM in serum IgM fractions, antibody capture ELISA-IgM, IgM-immunosorbent agglutination assay (ISAGA), and IgM immunoblotting. Basic immunosuppression consisted of cyclosporine and low-dose steroids. Before transplantation, 26 of 43 recipients showed serological evidence of infection. In serum samples from 15 (35%) recipients, specific antibodies were not detected. Approximately 50% of the heart donors, were toxoplasma seropositive. Eight of the fifteen seronegative recipients received hearts from toxoplasma-seropositive donors. In four of the eight recipients, seroconversion could be demonstrated with all tests used. In three of these four patients, clinical disease developed. One patient with strong serological evidence of toxoplasmosis died, but toxoplasma parasites and antigens were not detected at autopsy. In two patients, toxoplasma cysts were found in cardiac biopsies. Seroconversion was not prevented by the use of spiramycin prophylaxis in two recipients. Reactivations of latent infections or reinfections were detected by indirect ELISA in six (23%) seropositive recipients, but symptoms and signs of active T. gondii infection were not seen. Seroconversion and reactivation of infection were readily found by a combined use of indirect ELISA-IgG and ELISA-IgM and antibody capture ELISA-IgM. Discrepancies in results could be examined by immunoblotting. IgM-ISAGA retained stable positive values longer than IgM-ELISAs did. Cyclosporine treatment did not hamper detection of seroconversion but could cause antibody levels to remain relatively low in primary infections. Seronegative recipients should receive antitoxoplasma treatment on seroconversion.

Agglutination Tests↗
PubMed1988

Treatment with cyclosporin and risks of graft rejection in male kidney and heart transplant recipients with non-O blood.

In a consecutive series of 146 kidney transplant recipients treated with cyclosporin A a strong correlation between matching for the HLA-A, HLA-B, and HLA-DR loci specificities and outcome of the grafts was observed in male recipients with non-O blood groups. Such a beneficial effect of matching was not found in female patients or male patients with blood group O. In these patients survival of the grafts at one year was good irrespective of the number of HLA-A, B, and DR mismatches. Also in 47 male heart transplant recipients immune responsiveness against mismatched HLA antigens was related to blood group. A significantly higher incidence of rejection episodes was observed in male patients with non-O blood groups (n = 32) than in those with blood group O (n = 15). Matching for HLA-DR reduced the number of acute rejection episodes in male patients with non-O blood. These findings may help explain the controversial reports about the importance of HLA matching in organ transplantation. Furthermore, as most candidates for heart transplantation are male and not of blood group O, the higher incidence of graft rejection in these patients underscores the need for an exchange strategy of donor hearts.

ABO Blood-Group System↗