Biomedical subjects

H Haase

Publications and source records attributed to H Haase.

At least 37 records · Page 2Linked to original sources

PubMed2000

A comparison of the effects of two kinds of glass-ionomer cement on human gingival fibroblast attachment, proliferation and morphology in vitro.

The aim of this study was to compare the response of cultured human gingival fibroblasts to two kinds of glass-ionomer cement in vitro with regards to understanding the biocompatibility of these materials and their suitability for use as subgingival restorative materials. The glass-ionomer cements tested were Ketac Fil, and GC Fuji II. These cements were mixed according to the manufacturers' directions and condensed into tissue culture wells or cavities prepared on the root surfaces of extracted teeth. Healthy root slices and untreated tissue culture wells were used as controls. Several features such as attachment, proliferation and morphology of cells were studied. The results indicated that cells could not attach to the glass-ionomer cements unless they had been washed with distilled water and tissue culture media. No significant difference in initial attachment (1.5h) and long term attachment (48h) between the groups tested was noted. No significant difference was observed between levels of proliferation for human gingival fibroblasts grown on Ketac Fil, Fuji II, root slices and culture wells. No significant alterations of the cytomorphology could be detected in glass-ionomer cement compared with root slices. These results indicate that provided the surface is adequately washed, Ketac Fil, and Fuji II may be acceptable subgingival root surface restorative materials.

Analysis of Variance↗

PubMed1999

[Big differences in leadership and management training within health care services. Leadership and issues concerning cooperation should be more emphasized in basic medical education].

A recent survey of medical management programmes at universities across the country showed manifest national differences to exist, both quantitative and qualitative. Using a questionnaire, the Swedish Society of Medical Management examined the programmes for physiotherapists, occupational therapists, social workers, nurses and physicians, with respect to such issues as leadership, self-awareness and communication, health economics, and administration. It was concluded that knowledge acquired differs between fields; that physiotherapy programmes tend to have a very didactic approach; that nurses are taught the importance of participation in developmental processes; that doctors are exposed to somewhat the same approach but to a large extent on a voluntary basis; and that social workers obtain good insight into the administrative skills necessary to their work. In the article it is concluded that students would benefit from orientation in the diverse approaches used in the other fields than their own, and that pooling of resources among different programmes might be a more economic alternative to current practice.

Communication↗

PubMed1999

Remodeling of the hypertrophied human myocardium by cardiac bHLH transcription factors.

The basic helix-loop-helix transcription factors eHAND and dHAND are involved in developmental cardiac growth and differentiation. We investigated HAND gene expression in the normal and in the hypertrophied right and left ventricle of patients with tetralogy of Fallot (ToF) and hypertrophic obstructive cardiomyopathy (HOCM). HAND mRNA was constitutively expressed in the hypertrophied heart and increased in the hypertrophic tissue of both patient groups. HAND genes had a complementary left-right cardiac asymmetry of expression with dHAND predominantly in the right and eHAND in the left ventricle. The two cardiac bHLH factors have the ability to form heterodimers with the ubiquitous bHLH protein E12, subsequently recognizing E-boxes in the promoter region of target genes like ALC-1. We found a highly significant positive correlation between HAND and ALC-1 mRNA. The total ALC-1 protein level in ToF was smaller than in HOCM, although ALC-1 mRNA as well as HAND mRNA levels were significantly higher. ToF patients expressed around four times more ALC-1 mRNA for similar amounts of ALC-1 than HOCM patients. Suggesting disturbed ALC-1 translation in ToF, we found ALC-1 antisense mRNA expression in the hypertrophied, but not in the normal, ventricles. The higher the antisense/sense ALC-1 mRNA ratio, the lower ALC-1 protein was expressed.

Base Sequence↗

PubMed1999

Inhibition of crossbridge function in the normal human heart by hypoxic endothelial superfusate.

Endothelial cells release diffusible substances which modulate myocardial function. Oxygen pressure is one important factor for stimulation and modulation of endothelial function. Here we investigated the effects of a superfusate obtained from hypoxic (pO(2) 40-50 mmHg) porcine endothelial cell culture on human myocardial crossbridge cycling rate. Isometric force development and the rate constant for tension development of demembranated multicellular fibers from the left myocardium of a normal human heart were determined from the low-tension rigor by photolytic release of ATP from caged-ATP. Incubation with hypoxic or normoxic superfusates did not change maximal isometric force development. However, rate constant of tension development of the normal human heart fibers significantly decreased to 43.3% upon incubation with the hypoxic but not normoxic endothelial cell superfusate.

Adenosine Triphosphate↗

PubMed1999

Regulation of Limulus skeletal muscle contraction.

Skeletal muscle contraction of Limulus polyphemus, the horseshoe crab, seemed to be regulated in a dual manner, namely Ca2+ binding to the troponin complex as well phosphorylation of the myosin light chains (MLC) by a Ca2+/calmodulin-dependent myosin light chain kinase. We investigated muscle contraction in Limulus skinned fibers in the presence of Ca2+ and of Ca2+/calmodulin to find out which of the two mechanisms prevails in Limulus skeletal muscle contraction. Although skinned fibers revealed high basal MLC mono- and biphosphorylation levels (0.48 mol phosphate/mol 31 kDa MLC; 0.52 mol phosphate/mol 21 kDa MLC), the muscle fibers were fully relaxed at pCa 8. Upon C2+ or Ca2+/calmodulin activation, the fibers developed force (357+/-78.7 mN/mm2; 338+/-69.7 mN/mm2, respectively) while the MLC phosphorylation remained essentially unchanged. We conclude that Ca2+ activation is the dominant regulatory mechanism in Limulus skeletal muscle contraction.

Animals↗

PubMed1999

Plakoglobin is essential for myocardial compliance but dispensable for myofibril insertion into adherens junctions.

Plakoglobin (gamma-catenin), a member of the armadillo family of proteins, is a constituent of the cytoplasmic plaque of cardiac junctions and is involved in anchorage of cytoskeletal filaments to specific cadherins. Its genetic inactivation leads to an embryonic lethal phenotype due to heart dysfunction related to an impairment in the architecture of intercalated discs and in the stability of the heart tissue. To elucidate the functional consequences of the loss of plakoglobin for myofibrillar function, we monitored passive stress-strain relationship and contractility parameters of demembranated embryonic fibers. Heart fibers obtained from plakoglobin-deficient embryonic mice were significantly less compliant than were fibers from wild-type embryos. This difference was especially pronounced at lower fiber extension levels: at 120% of slack length, compliance was 2.5-fold lower in plakoglobin-deficient mice than in the corresponding wild-type group. Contractile paramenters (force per cross-section; Ca2+ sensitivity of isometric force and shortening velocity at near-zero load) were comparable in all experimental groups. Therefore, we suggest that plakoglobin is important for cardiac compliance but not necessary for the attachment of the myofibrillar apparatus to adherens junctions. Thus, we conclude that the loss of function of desmosomes and the profound disarrangement of junctional components in plakoglobin null embryos is associated with a decreased passive compliance, which may explain the ventricular rupture and consequent pericardial tamponade in embryos lacking plakoglobin.

Animals↗

PubMed1999

Expression of atrial myosin light chains but not alpha-myosin heavy chains is correlated in vivo with increased ventricular function in patients with hypertrophic obstructive cardiomyopathy.

The adult rodent heart adapts to increased work load by reexpression of its fetal genes, for example, beta-myosin heavy chain (MHC), in order to improve contractile function. However, the human ventricle regulates contractility by expression of atrial essential myosin light chain (ALC-1) rather than beta-MHC. We evaluated the impact of both mechanisms in patients with hypertrophic cardiomyopathy. MHC isoform expression was quantified at the mRNA and protein levels by reverse transcriptase polymerase chain reaction and immunoblotting, respectively. Although alpha-MHC mRNA was detected in control and hypertrophied human ventricular tissue, alpha-MHC protein was not observed. Similarly, we investigated the expression of ALC-1 by two-dimensional polyacrylamide gel electrophoresis and the clinical and hemodynamic parameters of the patients with hypertrophic cardiomyopathy. We found a significant positive correlation between ALC-1 protein expression and dP/dtmax in the hypertrophied human ventricle in vivo. Correlations between dP/dtmax and expression of protein for the ryanodine receptor and L-type Ca2+ channel were excluded. Our data suggest that reexpression of ALC-1 improves the contractile state of the adult human heart. We propose that two evolutionarily divergent compensatory mechanisms for increased work demand exist in the mammalian heart: MHC regulation in rodents and essential MLC regulation, of cardiac contractility, in humans.

Adult↗

PubMed1999

Uptake and intracellular distribution of labile and total Zn(II) in C6 rat glioma cells investigated with fluorescent probes and atomic absorption.

The uptake, intracellular distribution and cytotoxicity of high doses of extracellular zinc was investigated in C6 rat glioma cells. Net zinc uptake occurred only above certain thresholds in time and concentration, below them no alterations of the intracellular zinc level were observed. These results were obtained by measurements with the fluorescent dye Zinquin and by atomic absorption spectrometry, yielding similar results with both methods. Sequestration of zinc in intracellular vesicles was observed by fluorescence microscopy. A protective effect of vesicular sequestration is indicated, because increased levels of intracellular zinc located in vesicles did not necessarily lead to an increase in cytotoxicity. We were able to show that in C6 cells, in contrast to other cell lines, zinc that is released from proteins by the NO donor SNOC is also sequestered in vesicular structures. These zinc-carrying vesicles showed to be constitutive and are assumed to have a function in the maintainance of the cytosolic content of Zn2+ ions.

Animals↗

PubMed1999

Signaling from beta-adrenoceptor to L-type calcium channel: identification of a novel cardiac protein kinase A target possessing similarities to AHNAK.

A novel calcium channel-associated protein of approximately 700 kDa has been identified in mammalian cardiomyocytes that undergoes substantial cAMP-dependent protein kinase (PKA) phosphorylation. It was therefore designated as phosphoprotein 700 (pp700). The pp700 interacts specifically with the beta(2) subunit of cardiac L-type calcium channels as revealed by coprecipitation experiments using affinity-purified antibodies against different calcium channel subunits. It is surprising that amino acid sequence analysis of pig pp700 revealed homology to AHNAK-encoded protein, which was originally identified in human cell lines of neural crest origin as 700-kDa phosphoprotein. Cardiac AHNAK expression was assessed on mRNA level by reverse transcriptase-polymerase chain reaction. Sequence-directed antibodies raised against human AHNAK recognized pp700 in immunoblotting and immunoprecipitation experiments, confirming the homology between both proteins. Anti-AHNAK antibodies labeled preferentially the plasma membrane of cardiomyocytes in cryosections of rat cardiac tissue and isolated cardiomyocytes. Sarcolemmal pp700/AHNAK localization was not influenced by stimulation of either the PKA or the protein kinase C pathway. In back-phosphorylation studies with cardiac biopsies, we identified distinct pp700 pools. The membrane-associated fraction of pp700 underwent substantial in vivo phosphorylation on beta-adrenergic receptor stimulation by isoproterenol, whereas the cytoplasmic fraction of pp700 was not accessible to endogenous PKA. It is important that in vivo phosphorylation occurred in that pp700 fraction which coprecipitated with the calcium channel beta subunit. We hypothesize that both phosphorylation of pp700 and its coupling to the beta subunit play a physiological role in cardiac beta-adrenergic signal transduction. Haase, H., Podzuweit, T., Lutsch, G., Hohaus, A., Kostka, S., Lindschau, C., Kott, M., Kraft, R., Morano, I. Signaling from beta-adrenoceptor to L-type calcium channel: identification of a novel cardiac protein kinase A target that has similarities to AHNAK.

Amino Acid Sequence↗

PubMed1999

Diagnosis of atrial undersensing in dual chamber pacemakers: impact of autodiagnostic features.

Atrial undersensing occurs in a considerable number of patients, both with single lead VDD pacemakers and with DDD devices. The aim of this study was to investigate the diagnostic efficacy of electrocardiographic methods and autodiagnostic pacemaker features to detect atrial sensing dysfunction. Two hundred and thirty-one patients with AV block received single lead VDD pacemakers or DDD devices. Atrial sensitivity was programmed to 0.1 or 0.18 in VDD devices and to 0.5 mV in DDD devices; the rate limits were set to 40 and 160 beats/min. Twelve-lead ECG recording for 1 minute during deep respiration and change of body position, 24-hour Holter ECG recording, and treadmill exercise were performed 2 weeks and 15 months after pacemaker implantation. AV synchrony and, if available, P wave amplitude histogram were sampled by autodiagnostic pacemaker features and compared to electrocardiographic findings. Atrial undersensing was assumed, if AV synchrony was below 100% or if minimal P wave amplitude (PWA) was equal to the programmed atrial sensitivity. Intermittent atrial undersensing occurred in 20.7% of patients. The diagnostic sensitivities of the various methods used to detect atrial sensing failures were: 24-hour Holter monitoring 97.5%, P wave amplitude histogram 90.0%, stored AV synchrony 68.0% without significant difference between the various devices, treadmill exercise testing 58.8%, and 12-lead ECG recording 21.3%. In one patient, atrial undersensing was exclusively detected by exercise testing. In conclusion, autodiagnostic pacemaker features facilitate the evaluation of atrial sensing performance. However, to exclude intermittent atrial malesensing, routine Holter monitoring and treadmill exercise are still needed.

Aged↗

PubMed1999

Development of sinus node disease in patients with AV block: implications for single lead VDD pacing.

OBJECTIVE: To investigate the incidence of sinus node disease after pacemaker implantation for exclusive atrioventricular (AV) block. DESIGN: 441 patients were followed after VDD (n = 219) or DDD pacemaker (n = 222) implantation for AV block over a mean period of 37 months. Sinus node disease and atrial arrhythmias had been excluded by Holter monitoring and treadmill exercise preoperatively in 286 patients (group A). In 155 patients with complete AV block, a sinus rate above 70 beats/min was required for inclusion in the study (group B). Holter monitoring and treadmill exercise were performed two weeks, three months, and every six months after implantation. Sinus bradycardia below 40 beats/min, sinoatrial block, sinus arrest, or subnormal increase of heart rate during treadmill exercise were defined as sinus node dysfunction. RESULTS: Cumulative incidence of sinus node disease was 0.65% per year without differences between groups. Clinical indicators of sinus node dysfunction were sinus bradycardia below 40 beats/min in six patients (1.4%), intermittent sinoatrial block in two (0.5%), and chronotropic incompetence in five patients (1.1%). Only one of these patients (0.2%) was symptomatic. Cumulative incidence of atrial fibrillation was 2.0% per year, independent of the method used for the assessment of sinus node function and of the implanted device. CONCLUSIONS: In patients undergoing pacemaker implantation for isolated AV block, sinus node syndrome rarely occurs during follow up. Thus single lead VDD pacing can safely be performed in these patients.

Aged↗

PubMed1999

Should cementoblasts express alkaline phosphatase activity? Preliminary study of rat cementoblasts in vitro.

BACKGROUND: A well-characterized cell culture model for cementoblasts is essential to understand the mechanisms of periodontal ligament (PDL) reattachment and regeneration. Whether cementoblasts express alkaline phosphatase (ALP) activity in vivo and in vitro remains to be determined. METHODS: Using a 2-step method of enzyme digestion/explant culture, osteoblasts, gingival/PDL fibroblasts, and cementoblasts were obtained from alveolar bone, gingiva, and the root surface of rat first molars and cultured. Initially, bone sialoprotein (BSP) was immunolocalized on tissue sections of periodontium and on cultured cells to distinguish mineral-forming cells from fibroblasts. Proteins were extracted from these cells to assess ALP activity by using an enzyme assay. RNA was extracted from the same cell source to detect ALP mRNA by reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: Cultured PDL/gingival fibroblasts were spindle shaped. Osteoblasts were irregularly shaped, and cell clusters/nodules were observed as they approached confluence. The cementoblasts manifested a polygonal shape and had two morphotypes: osteoblast-like and cuboidal or stratified. BSP was localized within the mineralized tissues and in osteoblasts and cementoblasts in culture and in tissue sections. The highest level of ALP activity was found in osteoblasts, a moderate level in PDL fibroblasts, and the lowest level in gingival fibroblasts. The cementoblasts lacked ALP activity, and this was reflected by a very weak signal (or no signal at all) for ALP mRNA in the cementoblasts. CONCLUSIONS: These studies indicate that cells consistent with a cementoblast-like phenotype may be successfully cultured, and that they lack ALP activity.

Alkaline Phosphatase↗

PubMed1998

Expression of smooth muscle myosin heavy chain B in cardiac vessels of normotensive and hypertensive rats.

We investigated expression of the 5'-spliced isoform of smooth muscle myosin heavy chain (SM-MHC-B) in smooth muscle cells of cardiac vessels of the left ventricle of normotensive (Wistar-Kyoto) and spontaneously hypertensive rats of the stroke-prone strain by immunofluorescence microscopy. In parallel, liver and bladder were studied for characterization of the nature of vessels expressing SM-MHC-B and for semiquantitative evaluation of its abundance. Smooth muscle cells were detected by staining with a monoclonal antibody specific for alpha-smooth muscle actin. Abundance of the SM-MHC-B isoform in these cells was evaluated by using an antibody raised against the seven-amino acid insert at the 25K/50K junction of the myosin head (a25K/50K) that specifically recognized SM-MHC-B. In the ventricle, a25K/50K immunoreactivity was observed in smooth muscle cells of precapillary arterioles but not in larger vessels or aorta. The a25K/50K immunoresponse of those vessels with the highest expression level of SM-MHC-B closely resembled the signal observed in the smooth muscle layer of urinary bladder known to preferentially express SM-MHC-B. Interestingly, in left ventricles of stroke-prone spontaneously hypertensive rats, there was a significantly reduced fraction of a25K/50K-positive precapillary arterioles compared with normotensive control rats.

Animals↗

PubMed1998

Characterization of naturally occurring myosin heavy chain antisense mRNA in rat heart.

Analysis of mRNA by Northern blot and reverse transcription-polymerase chain reaction demonstrated the expression of sense and considerable amounts of naturally occurring antisense mRNA for beta-myosin heavy chain (MHC) and alpha-MHC in the neonatal rat heart: antisense MHC mRNA expression of alpha-MHC and beta-MHC was approximately half of the corresponding sense MHC mRNA expression. Using a computational approach, we could identify a reverse Pol II promoter in the beta-MHC gene. Both sense and antisense MHC mRNA demonstrated similar sizes of approximately 6,000 bp in the Northern blot. Alpha-MHC antisense mRNA consisted of approximately 3,700 bp of complementary exon sequences and beta-MHC consisted of approximately 2,700 bp, suggesting a higher probability of alpha-MHC mRNA dimerization. Hence, sense mRNA transcripts and protein of alpha-MHC should exist at different relative levels in the neonatal state. In fact, the relative proportion of alpha-MHC was 52.0 +/- 2.6% on the sense mRNA but only 36.3 +/- 1.8% on the protein level. Because of its high abundance in the heart, we suggest that in the neonatal heart naturally occurring antisense mRNA may play a role in the regulation of MHC expression and, therefore, in the control of the energetical and contractile behaviour of the heart.

Aging↗

PubMed1998

Differential expression and association of calcium channel alpha1B and beta subunits during rat brain ontogeny.

Calcium functions as an essential second messenger during neuronal development and synapse acquisition. Voltage-dependent calcium channels (VDCC), which are critical to these processes, are heteromultimeric complexes composed of alpha1, alpha2/delta, and beta subunits. beta subunits function to direct the VDCC complex to the plasma membrane as well as regulate its channel properties. The importance of beta to neuronal functioning was recently underscored by the identification of a truncated beta4 isoform in the epileptic mouse lethargic (lh) (Burgess, D. L., Jones, J. M., Meisler, M. H., and Noebels, J. L. (1997) Cell 88, 385-392). The goal of our study was to investigate the role of individual beta isoforms (beta1b, beta2, beta3, and beta4) in the assembly of N-type VDCC during rat brain development. By using quantitative Western blot analysis with anti-alpha1B-directed antibodies and [125I-Tyr22]omega-conotoxin GVIA (125I-CTX) radioligand binding assays, we observed that only a small fraction of the total alpha1B protein present in embryonic and early postnatal brain expressed high affinity 125I-CTX-binding sites. These results suggested that subsequent maturation of alpha1B or its assembly with auxiliary subunits was required to exhibit high affinity 125I-CTX binding. The temporal pattern of expression of beta subunits and their assembly with alpha1B indicated a developmental pattern of expression of beta isoforms: beta1b increased 3-fold from P0 to adult, beta4 increased 10-fold, and both beta2 and beta3 expression remained unchanged. As the beta component of N-type VDCC changed during postnatal development, we were able to identify both immature and mature forms of N-type VDCC. At P2, the relative contribution of beta is beta1b > beta3 >> beta2, whereas at P14 and adult the distribution is beta3 > beta1b = beta4. Although we observed no beta4 associated with the alpha1B at P2, beta4 accounted for 14 and 25% of total alpha1B/beta subunit complexes in P14 and adult, respectively. Thus, of the beta isoforms analyzed, only the beta4 was assembled with the rat alpha1B to form N-type VDCC with a time course that paralleled its level of expression during rat brain development. These results suggest a role for the beta4 isoform in the assembly and maturation of the N-type VDCC.

Age Factors↗

PubMed1998

Differentiation-dependent expression of cardiac delta-CaMKII isoforms.

Despite their important role in controlling the cardiac Ca2+ homeostasis, presence and functions of individual isoforms of the multifunctional Ca2+/calmodulin-dependent protein kinase in the heart are not well studied. Here we report on expression of isoforms of the delta class in two differentiation states of the embryonic rat heart-derived cell line H9c2 compared to adult rat heart. Reverse transcription coupled polymerase chain reaction analysis revealed specific expression patterns of four variants of the delta class (delta B, delta C, delta 4, delta 9) in adult rat heart, H9c2 myoblasts, and skeletal muscle-like H9c2 myotubes. delta C was identified as a common isoform with higher amounts in H9c2 cells and the prominent one in myoblasts. In contrast, expression of delta 9 accompanied cardiac as well as skeletal muscle differentiation. Expression of delta B, however, was representative for differentiated cardiac muscle, whereas delta 4 expression coincided with differentiation into the skeletal muscle-like state. Our results demonstrate differentiation-dependent isoform expression of the delta class of the multifunctional Ca2+/calmodulin-dependent protein kinase of muscle. The identification of cardiac target proteins for this kinase, e.g. the alpha 1-subunit of the L-type Ca2+ channel, the sarcoplasmic reticulum Ca(2+)-ATPase, phospholamban and the ryanodine receptor define H9c2 myoblasts as a suitable model system for further functional characterization of the identified cardiac delta isoforms.

Animals↗

PubMed1998

Immunocytochemical localization of the G-protein sub-unit, G(o) alpha, in rat heart. Implications for a role of G(o) alpha in secretion of cardiac hormones.

The cellular and sub-cellular localization of the G-protein subunit, G(o) alpha, in rat heart was determined by immunofluorescence and immunoelectron microscopy. Using antibodies directed against purified G(o) alpha and an antiserum raised against the C-terminal decapeptide of G(o) alpha, strong immunoreactivity was found in the conducting system of the heart, neurons, and atrial cardiomyocytes. Labeling of ventricles was weak compared to that of atria. In neurons, immunoelectron microscopy revealed G(o) alpha was localized along the inner surface of axolemma and on axoplasmal vesicles. G(o) alpha immunoreactivity in atrial and ventricular myocytes was not restricted to sarcolemma, but was also found on sub-sarcolemmal vesicles with characteristic caveolar morphology. At the level of intercalated discs, labeling was spread over the periphery of intercalated discs avoiding its membrane structures. Additionally, in atrial endocrine cardiomyocytes, approximately 60% of secretory granules revealed G(o) alpha-labeling on the cytoplasmic surface. A small number of these granules stood out due to particularly intense labeling. The observation that these granules were found most-frequently in sub-sarcolemmal areas suggests that they may be mature granules undergoing exocytosis. Therefore, G(o) alpha found on secretory granules of endocrine cardiomyocytes may have a function in regulated exocytosis of cardiac hormones. Sarcolemmal localization of G(o) alpha in atrial and ventricular cardiomyocytes supports the role of G(o) alpha in transmembrane signal transduction. Furthermore, caveolar localization of G(o) alpha may provide a compartmental basis for integrating G(o)-mediated signaling events.

Animals↗

PubMed1998

Expression and function of atrial myosin light chain 1 in the porcine right ventricle of normal and pulmonary hypertensive animals.

We investigated the expression of atrial myosin light chain 1 (ALC-1) and myosin cycling kinetics in the normal and hypertrophied right ventricle of the neonatal porcine heart. Right ventricular hypertrophy was induced by exposing piglets immediately after birth to hypobaric hypoxia for 3 days. Control piglets were kept under normal conditions for the same time. ALC-1 expression in the hypertrophied right ventricle was 16.9%. No ALC-1 expression could be observed in the right ventricle of control pigs. Force-velocity of chemically skinned right ventricular fibers was analyzed in order to examine the functional role of ALC-1 expression on myosin cross-bridge kinetics. Force generation per cross-section at maximal Ca2+ activation (pCa 4.5) was significantly higher in the hypertrophied group. Maximal shortening velocity (Vmax) of skinned fibers increased statistically significant from 0.69 muscle length per second (ML/s) in the control to 1.2 ML/s in the hypertrophied right ventricle. We conclude that the expression of ALC-1 in the hypertrophied ventricle of neonatal pigs increased cross-bridge cycling kinetics and contractility.

Animals↗