Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ENDOCARDIUM”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,171 records · Page 65Linked to original sources
PubMed2003

Temporal and topographic ultrastructural alterations of rat heart myofibrils caused by thyroid hormone.

In order to further our understanding regarding the temporal and topographic ultrastructural aspects of the myocardium under thyrotoxicosis, thyroxine (T4; 25 and 100 microg/100 g bw) was administered to young rats 24 hours after birth until 15 days. The animals were then sacrificed, the hearts excised and weighed, and the ventricle tissue samples were then processed for confocal and transmission electron microscopy. At 48/72 hours and 1 week after initiation of T4 treatment with 100 microg/100 g bw, numerous lamellar bodies (probably formed by phospholipids) progressively accumulated in the heart. These bodies were observed in the cytosol, inside mitochondria and in the extracellular matrix. At 2 weeks of T4 treatment with 100 microg/100 g bw, lamellar bodies were virtually absent. Changes in cell shape, disorganization of intercellular junctions, and substantial myofibrillar disarray were observed in many cardiomyocytes. A gradient of myofibrillar disarray, which increased in abundance and intensity from the endocardium to the epicardium, was also observed. Immunocytochemical staining for desmin showed that the arrangement of this protein was disorganized in many cells of T4-treated rats as compared with normal ones, confirming ultrastructural data. The predominant appearance of myofibrillar disarray, associated with disorganization of cytoskeletal proteins in the deep myocardium, may be due to higher mechanical wall stress and consequent higher metabolic demand. Alternatively, differential sensitivity of cardiomyocytes to thyroid hormone in different areas is also a possibility.

Animals↗
PubMed2004

Induction of the avian coelom with associated vitelline blood circulation by Rauber's sickle derived junctional endoblast and its fundamental role in heart formation.

In histological sections through chicken blastoderms of different ages we describe the temporospatial relationship between junctional endoblast, the formation of blood islands (appearing first from a peripherally migrating mesoblastic blastema), and the formation of coelomic vesicles developing later in/and from a more superficially extending mesoblastic blastema (coelomic mesoblast). After unilateral removal of the Rauber's sickle-derived junctional endoblast in early streak blastoderms (stage 2-4; Vakaet [1970] Arch Biol 81:387-426) and culture to stage 11 (Hamburger and Hamilton [1951] J Morphol 88:49-92), we observed that the early formation of the coelomic cavity was locally or totally disturbed in the operated area. Besides the simultaneous absence of blood islands, the coelomic vesicles did not form normally. Instead of regularly aligned coelomic vesicles, progressively forming the coelomic cavity by fusion, some voluminous irregular cavities appeared. Thus, the extent of the coelomic cavity was greatly reduced and the operated side was considerably smaller than the unoperated side. Furthermore, in the youngest operated blastoderms the cranial portion of the involved coelomic cavity (hemipericardial cavity) exhibited rudimentary development and usually did not reach the region of the foregut endoderm. This resulted in the absence of the myoepicardium and associated endocardium at this side. In another experiment, after removal of the junctional endoblast at one side of the chicken blastoderm, a fragment of quail junctional endoblast was placed isotopically. This resulted, after further in vitro culture, in the restoration of the formation of coelomic vesicles and accompanying subjacent blood islands in the immediate neighborhood of the apposed quail junctional endoblast. Also, the pericardium and primary heart tube developed normally. Similarly, by using the quail-chicken chimera technique, we demonstrated that the splanchnic mesoderm cells of the pericardium develop in intimate association with the most cranial part of the junctional endoblast (derived from the Rauber's sickle horns). Our experiments indicate that the coelom and, in particular, the pericardium and primary heart tube form progressively (in time and space) under the inductory influence of Rauber's sickle and junctional endoblast.

Animals↗
PubMed2005

Ventricle and outflow tract of the African lungfish Protopterus dolloi.

We report a morphologic study of the heart ventricle and outflow tract of the African lungfish Protopterus dolloi. The ventricle is saccular and appears attached to the anterior pericardial wall by a thick tendon. An incomplete septum divides the ventricle into two chambers. Both the free ventricular wall and the incomplete ventricular septum are entirely trabeculated. Only a thin rim of myocardium separates the trabecular system from the subepicardial space. The outflow tract consists of proximal, middle, and distal portions, separated by two flexures, proximal and distal. The proximal outflow tract portion is endowed with a layer of compact, well-vascularized myocardium. This portion is homologous to the conus arteriosus observed in the heart of most vertebrates. The middle and distal outflow tract portions are arterial-like, thus being homologous to the bulbus arteriosus. However, the separation between the muscular and arterial portions of the outflow tract is not complete in the lungfish. A thin layer of myocardium covers the arterial tissue, and a thin layer of elastic tissue underlies the conus myocardium. Two unequal ridges composed of loose connective tissue, the spiral and bulbar folds, run the length of the outflow tract. They form an incomplete division of the outflow tract, but fuse at the distal end. The two folds are covered by endocardium and contain collagen, elastin, and fibroblast-like cells. They appear to be homologous to the dextro-dorsal and sinistro-ventral ridges observed during the development of the avian and mammalian heart. Two to three rows of vestigial arterial-like valves appear in the dorsal and ventral aspects of the conus. These valves are unlikely to have a functional role. The possible functional significance of the "gubernaculum cordis," the thick tendon extending between the anterior ventricular surface and the pericardium, is discussed.

Animals↗
PubMed2002

Reproducibility of left ventricular mass measurement using a half-Fourier black-blood single-shot fast spin-echo sequence within a single breath hold: comparison with a conventional multiple breath-hold segmented gradient echo technique in patients.

PURPOSE: To compare the reproducibility of left ventricular (LV) mass measurements using a black-blood half-Fourier single-shot fast spin-echo (SSFSE) and a segmented gradient echo magnetic resonance (MR) pulse sequence. MATERIAL AND METHODS: Breath-hold SSFSE and segmented gradient echo cardiac MR examinations were performed twice in 32 patients and manual detection of the LV endocardium and epicardium was applied by two blinded reviewers. The SSFSE pulse sequence allowed whole-heart coverage in a single breath hold, while multiple breath holds were required using the segmented gradient echo sequence. Spatial presaturation slabs were used with the SSFSE pulse sequence to reduce the field of view (FOV) and thereby achieve higher spatial resolution. RESULTS: Intraclass correlation coefficients were higher with the SSFSE pulse sequence than with the segmented gradient echo pulse sequence: intraobserver reproducibility reached 0.999 vs. 0.991; interobserver reproducibility: 0.997 vs. 0.981; and interstudy reproducibility: 0.998 vs. 0.936. These higher levels of reproducibility were confirmed on Bland and Altman plots. CONCLUSION: LV mass measurements can be assessed more reproducibly with the single breath-hold SSFSE technique than with the standard multiple breath-hold segmented gradient echo method.

Adult↗
PubMed1983

Myocardial revascularization by laser: a clinical report.

Methods used to revascularize ischemic myocardium have included arterial reconstruction, coronary artery bypass grafting, providing direct circulation from the intraventricular chamber, and techniques to promote collateral circulation. Ventricular channels from the epicardial surface through the endocardium are readily made with the CO2 laser. Animal experiments suggest that these channels protect the ischemic myocardium and provide circulation to the muscle from the ventricular chamber. Clinical use of the CO2 laser in conjunction with aortocoronary bypass grafting is reported in a patient with three-vessel coronary artery disease and total occlusion of the left anterior descending coronary artery (LAD), and hypokinesis of the anterior wall and apex. Following bypass a series of laser channels were made in the hypokinetic area of the left ventricle. Postoperative myocardial Tc PYP scans were within normal limits, including the previously dyskinetic anterior apical area. Serial EKGs remained unchanged from the preoperative status. Creatinine phosphokinase-myocardial band (CPK-MB) was elevated to 6 on the first and second postop day and was 0 from the third day. The patient was not recatheterized. The technique of myocardial revascularization by laser may be a viable addition to present treatment modalities. Further investigation and long-term follow-up are needed.

Aged↗
PubMed1988

Selective laser ablation of venous thrombus: implications for a new approach in the treatment of pulmonary embolus.

Laser radiation was employed to ablate venous thrombus or emboli with parameters that would not injure endovascular tissues. Output from a 482-nm, 1-microsec pulsed dye laser was delivered through a 320-microns-diameter fiber to in vitro samples of fresh thrombus (T), venous or pulmonary emboli (VE), inferior vena cava (IVC), pulmonary artery (PA), pulmonary valve, and endocardium (atrial and ventricular). The mean threshold fluences for ablation of T and VE were 1.1 and 5.1 J/cm2, respectively. In contrast, the mean threshold fluences for IVC and PA were significantly higher (P less than 0.0001), at 120 and 124 J/cm2, respectively. Ablation efficiency of thrombus was in excess of 100 mg/J, under conditions that caused no histologic injury to the pulmonary artery. To correlate ablation studies with optical absorption by the tissues, optical properties of fresh T, VE, IVC, and PA were studied. Hemoglobin species accounted for the more than 10 times higher 482-nm absorption by T and VE compared to IVC and PA. This explains the differences in ablation thresholds and, thus, the selectivity encountered. These observations demonstrate, more than any other study in the vascular system, that with pulsed optical radiation, efficient laser ablation of venous thrombus is feasible with a wide margin of safety, and without damage to the surrounding vascular tissue.

Hemoglobin A↗
PubMed1994

Liposome-mediated DNA transfer into chicken primordial germ cells in vivo.

In embryogenesis, avian primordial germ cells (PGCs) circulate temporarily in the blood vessels at stages 10-15 (Hamburger and Hamilton, 1951), before reaching the gonads. In an attempt to transfer cloned genes into PGCs, liposome consisting of reporter plasmid DNA and N-[1-(2,3-Dioleoyloxy)propyl]-N,N,N-trimethylammoniummethylsulf ate was injected into the marginal veins of embryos at stages 11-15. As reporter plasmids, pRSVZ and pAcZ harboring the Escherichia coli lacZ gene driven, respectively, by the Rous sarcoma virus (RSV) promoter and the chicken beta-actin gene promoter were used. First, 55 embryos were injected with liposome containing pRSVZ and stained for the bacterial beta-galactosidase activity 24 hr after injection. In all the embryos, cells positive for beta-galactosidase activity were observed among the blood cells, endothelial cells, and endocardium cells of the heart, suggesting that transfection took place within the circulatory system. Then, embryos were injected with liposome containing pRSVZ or pAcZ, and stained 2 or 3 d after injection. PGCs positive for beta-galactosidase activity were observed in the gonads in four out of 44 embryos injected with pRSVZ, and 29 out of 71 embryos injected with pAcZ, indicating that the plasmid DNA was transferred into PGCs developing normally. The average number of positive PGCs per embryo was 0.2 and 2.1, respectively, when pRSVZ and pAcZ were introduced. The difference in the number of positive PGCs detected after introduction of the two plasmids suggests that the actin promoter has a higher level of transcriptional activity in PGCs than does the RSV promoter.

Animals↗
PubMed2002

Multislice first-pass cardiac perfusion MRI: validation in a model of myocardial infarction.

The purpose of this study was to validate a first-pass MRI method for imaging myocardial perfusion with multislice coverage and relatively small analyzable regions of interest (ROIs). A fast gradient-echo (FGRE) sequence with an echo-train (ET) readout was used to achieve multislice coverage, and a high dose of a contrast agent (CA) was used to achieve a high signal-to-noise ratio (SNR). Dogs (N = 6) were studied 1 day after reperfused myocardial infarction, and fluorescent microspheres were used as a standard for perfusion. First-pass MRI correlated well vs. microsphere flow, achieving mean R values of 0.87 (range = 0.82-0.93), 0.71 (range = 0.46-0.85), and 0.72 (range = 0.49-0.95) for subendocardial ROIs, transmural ROIs, and the endocardial-epicardial ratio, respectively. Additionally, analysis of myocardial time-intensity curves (TICs) indicated that 15.8 +/- 6 sectors, corresponding to 260 microl of endocardium, can be analyzed (R(2) > 0.95).

Animals↗
PubMed2002

Band artifacts due to bulk motion.

Band artifacts due to bulk motion were investigated in images acquired with fast gradient echo sequences. A simple analytical calculation shows that the width of the artifacts has a square-root dependence on the velocity of the imaged object, the time taken to acquire each line of k-space and the field of view in the phase-encoding direction. The theory furthermore predicts that the artifact width can be reduced using parallel imaging by a factor equal to the square root of the acceleration parameter. The analysis and results are presented for motion in the phase- and frequency-encoding directions and comparisons are made between sequential and centric ordering. The theory is validated in phantom experiments, in which bulk motion is simulated in a controlled and reproducible manner by rocking the scan table back and forth along the bore axis. Preliminary cardiac studies in healthy human volunteers show that dark bands may be observed in the endocardium in images acquired with nonsegmented fast gradient echo sequences. The fact that the position of the bands changes with the phase-encoding direction suggests that they may be artifacts due to motion of the heart walls during the image acquisition period.

Artifacts↗
PubMed1993

Spatially localized 31P NMR measurements of longitudinal relaxation rates in the canine myocardium.

FLAX-ISIS spatial localization was combined with inversion recovery to enable the measurement of spatially localized T1 values. This approach was applied to the transmural determination of creatine phosphate longitudinal relaxation times in the canine myocardium. By examining five voxels spanning the left myocardial wall, we observed that transmural T1 values for creatine phosphate ranged from 3.61 +/- 0.20 in the endocardium to 4.00 +/- 0.20 in the epicardium at 4.7 Tesla. As such, the canine myocardium exhibits no transmural variation in the T1 values of creatine phosphate. This simple approach can be extended to enable the in vivo measurement of transmural enzymatic rates.

Animals↗
PubMed1996

Spatial mapping of nitric oxide generation in the ischemic heart using electron paramagnetic resonance imaging.

Recently, it has been shown that rat hearts subjected to global ischemia generate nitric oxide (NO) and that a significant portion of it is generated by the reduction of nitrite under the acidic and reducing conditions that occur during myocardial ischemia [Zweier, Wang, Samouilov, Kuppusamy, Nature Med. 1, 804-809 (1995)]. In the present study it is further attempted to map the spatial distributions of the NO generation in the ischemic myocardium using L-band electron paramagnetic resonance imaging. Rat hearts were loaded with 10 mM nitrite and subjected to global no-flow ischemia, during which time a series of three-dimensional spatial electron paramagnetic resonance (EPR) images of the distribution of NO were obtained using the NO trap bis(N-methyl-D-glucamine dithiocarbamate)iron(II). The images clearly showed that NO is formed throughout the myocardium. Kinetic experiments showed that maximum NO generation and trapping occur at the midmyocardium and spread out to endocardium and epicardium of the left ventricle. The magnitude of generation in the RV myocardium is four- to fivefold lower than in the LV.

Animals↗
PubMed2005

Amyloid deposits in transthyretin-derived amyloidosis: cleaved transthyretin is associated with distinct amyloid morphology.

The pathological fibrillar deposits found in the heart and other organs of patients with senile systemic amyloidosis (SSA) and Swedish familial amyloidotic polyneuropathy (FAP) contain wild-type (wt) and a mutant form of transthyretin (TTR), respectively. Previously, it was reported that these two forms of amyloid have different molecular features and it was thus postulated that the mechanism responsible for TTR fibrillogenesis in SSA and FAP may differ. To document further the nature of the amyloid in these entities, detailed morphological, histochemical, immunological, and structural analyses of specimens obtained from 14 individuals with SSA and 11 Swedish FAP patients have been performed. Two distinct patterns of amyloid deposition (designated A and B) were evident. In pattern A, found in all SSA and five of 11 FAP cases, the amyloid had a homogeneous but patchy distribution within the sub-endocardium, sub-epicardium, and myocardium; exhibited weak congophilia and green birefringence; and was composed of tightly packed, short, unorientated fibrils. This material contained mainly approximately 79-residue C-terminal fragments of the amyloidogenic precursor protein. In pattern B, seen in the six other FAP patients, the amyloid appeared as thin streaks throughout the cardiac tissue; often surrounded individual muscle cells; was strongly congophilic and birefringent; had long fibrils arranged in parallel bundles, often penetrating into myocytes; and was composed of virtually intact TTR molecules. These findings provide substantive evidence for the morphological and structural heterogeneity of TTR fibrils and suggest that the two types of deposition may reflect fundamental differences in the pathogenesis of the TTR-associated amyloidoses.

Adult↗
PubMed1988

Prenatal sonographic diagnosis of endocardial fibroelastosis secondary to aortic stenosis.

Endocardial fibroelastosis is characterized by a diffuse thickening of the left ventricular endocardium with or without other cardiac anomalies. This entity had been diagnosed prenatally previously (Bovicelli et al., 1984) at a gestational age of 36 weeks. A case of endocardial fibroelastosis due to aortic stenosis accompanied by pericardial effusion, ascites, and hydramnion, diagnosed ultrasonographically and confirmed pathologically at 21 weeks of gestation, is presented.

Adult↗
PubMed2004

Evaluation of fetal cardiac contractility by two-dimensional ultrasonography.

OBJECTIVE: Evaluation of fetal cardiac contractility by two-dimensional ultrasonography and construction of nomograms of area shortening fraction, end-diastolic area and end-systolic area of fetal cardiac ventricles during uncomplicated pregnancy. MATERIALS AND METHODS: Fetal echocardiography was performed on 160 pregnant women between 14 and 28 weeks' gestation. Measurements were taken on the four-chamber view. The area of each ventricle was measured by tracing the endocardium at the end of systole and at the end of diastole. Area shortening fraction was calculated by the following formula: SF = (Ad - As)/Ad (SF--area shortening fraction, Ad--end-diastolic ventricular area, As--end-systolic ventricular area). RESULTS: A statistically significant increase in normal fetal area shortening fraction, end-diastolic area and end-systolic area of both ventricles with advancing gestational age was established. There were no significant differences in the area shortening fraction between right and left ventricles. CONCLUSIONS: Area shortening fraction shows good correlation with gestational age. Nomogram of area shortening fraction, end-diastolic area and end-systolic area of both ventricles can be used as the reference for evaluation of ventricle size and cardiac contractility in normal and pathological cases.

Adult↗
PubMed1993

Serotonin and cardiac morphogenesis in the mouse embryo.

The possible involvement of the neurotransmitter serotonin (5-HT) and its binding protein (SBP) in cardiac morphogenesis was studied using mouse whole embryo culture (together with immunocytochemistry or 3H-thymidine autoradiography) and a cell migration assay. Embryos were cultured before and during the period of endocardial cushion formation, embryonic (E) days 9-12, in the presence of 5-HT, the monoamine oxidase (MAO) inhibitor nialamide, or an uptake inhibitor (fluoxetine or sertraline). For the migration assay, cells from the outflow tracts of E12 embryos were dissociated and placed in a chemotaxis chamber together with different concentrations of 5-HT. E9 embryos cultured in the presence of 10 microM 5-HT and nialamide exhibited intense 5-HT immunoreactivity (5-HT IR) throughout the myocardium. This staining was greatly diminished by fluoxetine, sertraline, or the absence of nialamide. As morphogenesis proceeded, myocardial staining in embryos exposed to 5-HT became restricted to developing endocardial cushion forming regions and was more completely blocked by uptake inhibitors. No evidence for 5-HT synthesis by myocardium was found at any age studied using the precursor L-tryptophan. SBP was present in endocardial cushions in cultured and uncultured embryos. 3H-thymidine autoradiography demonstrated that both fluoxetine and sertraline inhibited proliferation of cardiac mesenchyme, endocardium, and myocardium. These effects were most pronounced when exposure began at E9 (prior to cushion formation). Dose-dependent effects of 5-HT on migration of outflow tract cells were also observed. Taken together, these results suggest that 5-HT may play a role in cardiac morphogenesis during endocardial cushion formation.

1-Naphthylamine↗
PubMed2004

Increased cardiac atrial-to-ventricular length ratio in the fetal four-chamber view: a new marker for atrioventricular septal defects.

OBJECTIVES: Atrioventricular septal defects (AVSDs) are the most common cardiac abnormality in fetuses with numerical chromosomal aberrations, in particular trisomy 21. The majority of AVSDs are not detected by routine ultrasound examination in pregnancy. We report two simple cardiac measurements that may substantially improve antenatal detection of AVSDs. METHODS: Cross-sectional ultrasound images through the fetal thorax demonstrating the four-chamber plane of the heart were obtained in 123 normal fetuses between 10 and 38 weeks of gestation. Heart length was measured at the level of interventricular septum by placing the calipers on the epicardium at the apex of the heart and on the endocardium at the top of the atrium. Ventricular length was measured by shifting the atrial caliper to the crossing point of the ventricular septum and mitral valve. Atrial length was calculated as the difference between the heart length and ventricular length. Based on these measurements, the atrial-to-ventricular length (AVL) ratio was calculated. Data were compared to measurements from 29 consecutive fetuses with AVSD between 13 and 39 weeks of gestation. RESULTS: In normal fetuses, the AVL ratio did not change with gestation and the mean AVL ratio was 0.47 (95% prediction interval 0.35 to 0.63). In the AVSD group, the mean AVL ratio was 0.77 (range, 0.59-0.99). If a cut-off value for the AVL ratio of 0.6 was chosen, the detection rate of AVSD was 86.2% at a 5.7% false-positive rate. For a 100% detection rate, the false-positive rate was 7.3%. CONCLUSIONS: The AVL ratio can accurately discriminate between hearts with AVSDs and normal cardiac anatomy. Incorporation of the AVL ratio measurement into routine antenatal ultrasonography may substantially improve the ability to diagnose AVSDs antenatally.

Case-Control Studies↗
PubMed1998

Adult KCNE1-knockout mice exhibit a mild cardiac cellular phenotype.

The KCNE1 gene encodes a channel regulator IsK which in association with the KvLQT1 K+ channel protein determines the slow component of the cardiac delayed rectifier current. We have investigated the cellular electrophysiological characteristics of adult KCNE1-knockout mouse hearts by means of the standard microelectrode technique. Action potential parameters from the ventricular endocardium of KCNE1 -/- mice were indistinguishable from those of KCNE1 +/+ animals. In particular, KCNE1 -/- hearts did not exhibit prolonged repolarization. E-4031, a specific blocker of erg K+ channels consistently prolonged repolarization in KCNE1 +/+ but not in KCNE1 -/- hearts. By contrast, the chromanol compound 293B, a specific blocker of KvLQT1 K+ channel produced comparable effects on repolarization in KCNE1 -/- and KCNE1 +/+ mice. We conclude that invalidation of the mouse KCNE1 gene by homologous recombination leads to a mild cardiac phenotype at the cellular level.

Action Potentials↗
PubMed1997

GATA-5: a transcriptional activator expressed in a novel temporally and spatially-restricted pattern during embryonic development.

Members of the GATA family of zinc finger transcription factors regulate critical steps of cellular differentiation during vertebrate development. In the studies described in this report, we have isolated and functionally characterized the murine GATA-5 cDNA and protein and defined the temporal and spatial pattern of GATA-5 gene expression during mammalian development. The amino terminus of the mouse GATA-5 protein shares high level amino acid sequence identity with the murine GATA-4 and -6 proteins, but not with other members of the GATA family. GATA-5 binds to the functionally important CEF-1 nuclear protein binding site in the cardiac-specific slow/cardiac troponin C (cTnC) transcriptional enhancer and overexpression of GATA-5 transactivates the cTnC enhancer in noncardiac muscle cell lines. During embryonic and postnatal development, the pattern of GATA-5 gene expression differs significantly from that of other GATA family members. In the primitive streak embryo, GATA-5 mRNA is detectable in the precardiac mesoderm. Within the embryonic heart, the GATA-5 gene is expressed within the atrial and ventricular chambers (ED 9.5), becomes restricted to the atrial endocardium (ED 12.5), and is subsequently not expressed in the heart during late fetal and postnatal development. Moreover, coincident with the earliest steps in lung development, only the GATA-5 gene is expressed within the pulmonary mesenchyme. Finally, the GATA-5 gene is expressed in tissue-restricted subsets of smooth muscle cells (SMCs), including bronchial SMCs and SMCs in the bladder wall. These data are consistent with a model in which GATA-5 performs a unique temporally and spatially restricted function in the embryonic heart and lung. Moreover, these data suggest that GATA-5 may play an important role in the transcriptional program(s) that underlies smooth muscle cell diversity.

3T3 Cells↗