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Biomedical subjects

L Q Zhang

Publications and source records attributed to L Q Zhang.

At least 19 recordsLinked to original sources
PubMed2026

[Analysis of clinical spectrum and genotype characteristics of 9 cases of Fabry disease].

Objective: To investigate the genetic characteristics and clinical phenotypes across different genotypes in patients with Fabry disease. Methods: Clinical data of 9 confirmed FD patients treated from June 2019 to December 2025 at the Affiliated Huai'an No.1 people's Hospital of Nanjing Medical University were retrospectively analyzed. The diagnostic criteria for FD included α-galactosidase A (α-GalA) activity, GLA gene sequencing, globotriaosylsphingosine levels, and renal biopsy findings, supplemented by clinical symptoms and signs. Genetic testing was performed on both the proband and their family members. Proband underwent next-generation sequencing of the GLA gene using the long-range PCR. Family members were verified by conventional PCR combined with Sanger sequencing. Variants were classified according to the 2015 American College of Medical Genetics and Genomics guidelines for sequence variation interpretation. Results: Of the 9 patients, 4 were males and 5 were females. The mean α-Gal A activity was (0.47±0.13) μmol·L-1·h-1 in males and (2.38±0.91) μmol·L-1·h-1 in females. The mean age at diagnosis was (43.0±16.7) years. The main clinical manifestations included renal impairment in 7 cases (proteinuria, chronic kidney disease, or end-stage renal disease), cardiac involvement in 8 cases (myocardial hypertrophy, arrhythmia, etc.), and autonomic nervous system symptoms in 6 cases (hypohidrosis). Pathogenic or likely pathogenic GLA variants were identified in all 9 patients, of which 8 were classified as pathogenic and 1 as a variant of uncertain significance. Three patients underwent family screening: in one case, the variant was possibly inherited from the maternal grandmother; one case was confirmed as a de novo mutation; and in one case, paternal inheritance could not be excluded. Renal biopsy in one patient revealed characteristic myeloid bodies and zebra bodies. Among the 9 patients, 1 received agalsidase α and 8 received agalsidase β, with one case developing infusion-associated reactions after 12 infusions. During the follow-up period, one patient died due to cardiac complications. Conclusions: FD patients exhibit a broad clinical spectrum and diverse genotypes. Atypical presentations should be closely monitored to enable early diagnosis and treatment, thereby improving prognosis.

Humans↗
PubMed2005

Excess propagation and biological control of zooplanktonic Cyclops in drinking water sources.

Starting with the occurrence of Cyclops in drinking water sources and its danger to drinking water safety, we extensively investigated the nature of its excess propagation by analyzing the effect of living space and predator pressure in the food chain on its survival. Then we developed an ecological project using fish biomanipulation, different to the conventional fishery culture technique, to control excess propagation of Cyclops. The control effects on Cyclops of four species of fish were investigated experimentally at a stocking density of 30 g/m3 of water. Results showed that the food habit of the fish had a significant influence on the biological control of Cyclops. The propagation of Cyclops could be controlled effectively and also the water quality improved simultaneously by stocking filter-feeding fish, such as silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis). However, herbivorous Ctenopharyngodon idellus and omnivorous Cyprinus carpio had no obvious biological effects on controlling the growth of Cyclops and restoring water quality. The results further proved that under conditions of proper poly-culture densities of silver carp and bighead carp, the number of Cyclops might be controlled at very low levels and eutrophication might be abated by removing nutrients from the water body.

Animals↗
PubMed2004

Diverse hepatitis C virus glycoproteins mediate viral infection in a CD81-dependent manner.

We recently reported that retroviral pseudotypes bearing the hepatitis C virus (HCV) strain H and Con1 glycoproteins, genotype 1a and 1b, respectively, require CD81 as a coreceptor for virus-cell entry and infection. Soluble truncated E2 cloned from a number of diverse HCV genotypes fail to interact with CD81, suggesting that viruses of diverse origin may utilize different receptors and display altered cell tropism. We have used the pseudotyping system to study the tropism of viruses bearing diverse HCV glycoproteins. Viruses bearing these glycoproteins showed a 150-fold range in infectivity for hepatoma cells and failed to infect lymphoid cells. The level of glycoprotein incorporation into particles varied considerably between strains, generally reflecting the E2 expression level within transfected cells. However, differences in glycoprotein incorporation were not associated with virus infectivity, suggesting that infectivity is not limited by the absolute level of glycoprotein. All HCV pseudotypes failed to infect HepG2 cells and yet infected the same cells after transduction to express human CD81, confirming the critical role of CD81 in HCV infection. Interestingly, these HCV pseudotypes differed in their ability to infect HepG2 cells expressing a panel of CD81 variants, suggesting subtle differences in the interaction of CD81 residues with diverse viral glycoproteins. Our current model of HCV infection suggests that CD81, together with additional unknown liver specific receptor(s), mediate the virus-cell entry process.

Amino Acid Sequence↗
PubMed2001

Dynamic and static control of the human knee joint in abduction-adduction.

It is unclear whether humans can voluntarily control dynamic and static properties in knee abduction-adduction, which may be important in performing functional tasks and preventing injuries, whether the main load is about the abduction axis or not. A joint-driving device was used to perturb the knee in abduction-adduction at full knee extension under both passive (muscle relaxed) and active (muscle contracted in abduction or adduction) conditions. Dynamic control properties in knee abduction-adduction were characterized by joint stiffness, viscosity, and limb inertia, and quasi-static knee torque-angle relationship was characterized by knee abduction-adduction laxity and quasi-static stiffness (at a 20Nm moment). It was found that the subjects were capable of generating net abduction and adduction moment through differential co-contraction of muscles crossing the medial and lateral sides of the knee, which helped to reduce the abduction-adduction joint laxity (p< or =0.01) and increase stiffness (p<0.027) and viscous damping. Knee abduction laxity was significantly lower than adduction laxity (p=0.043) and the quasi-static abduction stiffness was significantly higher than adduction stiffness (p<0.001). The knee joint showed significantly higher stiffness and viscosity in abduction-adduction than their counterparts in knee flexion-extension at comparable levels of joint torque (p<0.05). Similar to dynamic flexion-extension properties, the system damping ratio remained constant over different levels of contraction, indicating simplified control tasks for the central nervous system; while the natural undamped frequency increased considerably with abduction-adduction muscle contraction, presumably making the knee a quicker system during strenuous tasks involving strong muscle contraction.

Adult↗
PubMed2001

An HphI polymorphism in the E-selectin gene is associated with premature coronary artery disease.

An increased expression of E-selectin has been observed in the arterial endothelium interacting with lymphocytes and macrophages in human atherosclerotic lesions. We examined whether a polymorphism in the E-selectin gene, due to a G to T mutation (G98T) in the untranslated region of exon 2, was associated with premature coronary artery disease (CAD). Other lipid and nonlipid risk factors including a Ser to Arg (S128R) substitution in the E-selectin gene were also assessed. In patients with premature CAD (men < or = 45 years old and women < or =55 years old, N = 51) who underwent an elective diagnostic coronary arteriography, the frequency of the mutation was significantly higher than in controls (N = 50, 0.22 vs. 0.10, p = 0.024). After controlling for other CAD risk factors (plasma total cholesterol, triglyceride, LDL-apolipoprotein B. cigarette smoking and the S128R mutation) by multiple logistic analysis, the G98T mutation in the E-selectin gene was still a significant predictor of premature CAD [p = 0.022, odds ratio (95%, CI)= 3.58 (1.20-10.67)].

Alleles↗
PubMed2001

Muscle strength in knee varus and valgus.

PURPOSE: The purpose of this study was to investigate the lower-limb muscle strength in knee varus-valgus and its dependence on knee varus-valgus position. The hypothesis was that humans could differentially contract the medial and lateral muscles crossing the knee and generate significant moments in knee valgus-varus. METHODS: The subjects sat with the knee at full extension and secured from the medial, lateral, anterior, and posterior sides. Both hips were clamped from the lateral sides. The subjects adducted (abducted) the ipsilateral hip during the knee valgus (varus) maximal voluntary contraction with EMG signals recorded from muscles crossing the knee and knee joint moments measured using a six-axis force sensor. Frontal plane tibiofemoral movement was evaluated using a fluoroscope. RESULTS AND CONCLUSIONS: The subjects differentially contracted the medial and lateral muscles, and fluoroscope images showed the corresponding tibiofemoral movement. The subjects showed considerable strength in knee varus and valgus. The active knee varus strength increased significantly with increasing knee valgus angle, and the valgus strength was significantly higher when the knee was in varus position (P < 0.039). Active valgus muscle strength at 5 degrees knee varus was significantly higher than the active varus strength at 5 degrees valgus (P = 0.002). The passive resistance moment increased linearly with increasing knee valgus and varus angles, and it accounted for 28% and 35% of the total (active plus passive) moment at the 5 degrees varus and 5 degrees valgus, respectively. The significant varus-valgus muscle strength demonstrated in this study may play important roles in performing various functional tasks, maintaining joint stability, and preventing potential injuries, whether the major load and motion at the knee is in the frontal plane or not.

Adult↗
PubMed2001

Sprint training shortens prolonged action potential duration in postinfarction rat myocyte: mechanisms.

Two electrophysiological manifestations of myocardial infarction (MI)-induced myocyte hypertrophy are prolongation of action potential duration (APD) and reduction of transient outward current (I(to)) density. Because high-intensity sprint training (HIST) ameliorated myocyte hypertrophy and improved myocyte Ca(2+) homeostasis and contractility after MI, the present study evaluated whether 6-8 wk of HIST would shorten the prolonged APD and improve the depressed I(to) in post-MI myocytes. There were no differences in resting membrane potential and action potential amplitude (APA) measured in myocytes isolated from sham-sedentary (Sed), MI-Sed, and MI-HIST groups. Times required for repolarization to 50 and 90% APA were significantly (P < 0.001) prolonged in MI-Sed myocytes. HIST reduced times required for repolarization to 50 and 90% APA to values observed in Sham-Sed myocytes. The fast and slow components of I(to) were significantly (P < 0.0001) reduced in MI-Sed myocytes. HIST significantly (P < 0.001) enhanced the fast and slow components of I(to) in MI myocytes, although not to levels observed in Sham-Sed myocytes. There were no significant differences in steady-state I(to) inactivation and activation parameters among Sham-Sed, MI-Sed, and MI-HIST myocytes. Likewise, recovery from time-dependent inactivation was also similar among the three groups. We suggest that normalization of APD after MI by HIST may be mediated by restoration of I(to) toward normal levels.

Action Potentials↗
PubMed2001

Reflex and intrinsic changes induced by fatigue of human elbow extensor muscles.

Fatigue-induced changes in intrinsic and reflex properties of human elbow extensor muscles and the underlying mechanisms for fatigue compensation were investigated. The elbow joint was perturbed using small-amplitude and pseudorandom movement patterns while subjects maintained steady levels of mean joint extension torque. Intrinsic and reflex properties were identified simultaneously using a nonlinear delay differential equation model. Intrinsic joint properties were characterized by measures of joint stiffness, viscous damping, and limb inertia and reflex properties characterized by measures of dynamic and static reflex gains. Fatigue was induced using 15 min of intermittent voluntary isometric (submaximal) exercise, and a rest period of 10 min was taken to allow the fatigued muscles to recover from acute fatigue effects. Identical experimental and data analysis procedures were used before and after fatigue. Our findings were that after fatigue, joint stiffness was significantly reduced at higher torque levels, presumably reflecting the reduced force-generating capacity of fatigued muscles. Conversely, joint viscosity was increased after fatigue potentially because of the reduced crossbridge detachment rate and prolonged relaxation associated with intracellular acidosis accompanying fatigue. Static stretch reflex gain decreased significantly at higher torque levels after fatigue, indicating that the isometric fatiguing exercise might be associated with a preferential change in properties of spindle chain fibers and bag(2) fibers. For matched pre- and postfatigue torque levels, dynamic reflexes contributed relatively more torque after fatigue, displaying higher dynamic reflex gains and larger dynamic electromyographic responses elicited by the controlled small-amplitude position perturbations. These changes appear to counteract the fatigue-induced reductions in joint stiffness and static reflex gain. The compensatory responses could be partly due to the effects of increasing the number of active motoneurons innervating the fatiguing muscles. This shift in operating point gave rise to significant compensation for the loss of contractile force. The compensation could also be due to fusimotor adjustment, which could make the dynamic reflex gain much less sensitive to fatigue than intrinsic stiffness. In short, the reduced contribution from intrinsic stiffness to joint torque was compensated by increased contribution from dynamic stretch reflexes after fatigue.

Adult↗
PubMed2001

Innervation of normal and hypertrophic human scars and experimental wounds in the rat.

The present study was designed to investigate the role of nerve elements in normal and aberrant human wounds, and in experimental rat wound healing model. The innervation of normal and hypertrophic human scars was studied using indirect immunofluorescence labeling with antibodies specific for neurofilament protein. Furthermore, ingrowth of axons into experimental rat wounds was assayed. The results demonstrated that, in contrast to normal wounds, hypertrophic scars were traversed by a high number of bundles of axons. Our results also demonstrated that experimental rat granulation tissue which represented early phases of wound healing attracted axonal growth. To conclude, our findings indicate that normal wound healing is accompanied with innervation of the scars, and that hypertrophy of scars is accompanied with hypertrophy of nerves within the scars. Our results also suggest that aberrations in the innervation of scars may either cause aberrant wound healing, or neural hypertrophy may be a result of disturbed interplay in wound healing mechanisms.

Adult↗
PubMed2001

Innervation of normal and hypertrophic human scars and experimental wounds in the rat.

The present study was designed to investigate the role of nerve elements in normal and aberrant human wounds, and in experimental rat wound healing model. The innervation of normal and hypertrophic human scars was studied using indirect immunofluorescence labeling with antibodies specific for neurofilament protein. Furthermore, in-growth of axons into experimental rat wounds was assayed. The results demonstrated that, in contrast to normal wounds, hypertrophic scars were traversed by a high number of bundles of axons. Our results also demonstrated that experimental rat granulation tissue which represented early phases of wound healing attracted axonal growth. To conclude, our findings indicate that normal wound healing is accompanied with innervation of the scars, and that hypertrophy of scars is accompanied with hypertrophy of nerves within the scars. Our results also suggest that aberrations in the innervation of scars may either cause aberrant wound healing, or neural hypertrophy may be a result of disturbed interplay in wound healing mechanisms.

Adult↗
PubMed2000

miniSAGE: gene expression profiling using serial analysis of gene expression from 1 microg total RNA.

The use of serial analysis of gene expression (SAGE) to determine gene expression profiles is increasing because the technique can provide absolute transcript numbers in a digital format and identify new genes. We developed a miniSAGE technique, which uses only 1 microg total RNA and reduces the amount of the starting material by 250- to 500-fold. Unlike the other modified SAGE methods, the miniSAGE technique does not require the additional PCR amplifications. The additional PCR amplifications potentially introduce bias and compromise the quantitative aspects of the SAGE method. Three key modifications in the miniSAGE technique are: (i) using the phase lock gel (PLG, Eppendorf) to increase the recovery and the purity of DNA material after each phenol extraction step; (ii) reducing the amount of linkers in the ligation, thereby minimizing their interference with SAGE ditag amplification and increasing the SAGE ditag yield; and (iii) employing the mRNA capture kit (Boehringer Mannheim) to allow the first five steps: mRNA isolation, cDNA synthesis, enzyme cleavage of cDNA, binding of the cleaved biotin-cDNA to the streptavidin-magnetic beads, ligating linkers to the bound cDNA, and the release of cDNA tags to occur within one tube to significantly reduce the loss of material between successive steps. Two fibroblast SAGE libraries have been successfully prepared. The preliminary analysis of 3838 tags from one library demonstrated a typical fibroblast gene expression pattern. This miniSAGE technique will permit a broader application of SAGE.

Biopsy↗
PubMed2000

Identification of subdominant cytotoxic T lymphocyte epitopes encoded by autologous HIV type 1 sequences, using dendritic cell stimulation and computer-driven algorithm.

Conventional analysis of the cytotoxic T lymphocyte (CTL) response to HIV-1 may underestimate the true breadth of CTL epitopes recognized. This underestimation could be due to several reasons, including (1) the use of laboratory-adapted stains of HIV or consensus sequences, which would lead to the identification of only highly conserved epitopes, (2) the use of EBV-transformed B cells (B-LCLs) and vaccinia virus constructs in standard assays that may obscure low level CTL responses due to high EBV or vaccinia reactivity, and (3) relatively insensitive assays wherein PBMCs instead of professional APCs are used to stimulate CTL responses. To address these problems, we first identified an immunodominant HLA-B7-restricted CTL epitope, by standard cloning methods, in a long-term nonprogressor (LTNP). To determine whether the patient had CTLs specific for autologous viral sequences other than the dominant epitope, proviral DNA was cloned and sequenced. A matrix-based epitope algorithm (EpiMatrix) was used to identify the top 2% of peptides from the viral sequences with the highest likelihood of binding to HLA-B7. These 55 peptides were synthesized and tested for HLA-B7 binding in a T2/B7 cell line; 10 peptides were able to stabilize HLA-B7 on the cell surface. By using peptide-pulsed autologous dendritic cells as a more sensitive method of CTL stimulation, we found three additional subdominant CTL epitopes.

Algorithms↗
PubMed2000

Stiffness, viscosity, and upper-limb inertia about the glenohumeral abduction axis.

To evaluate the dynamic properties of the shoulder and understand how they are controlled by the central nervous system, glenohumeral-joint stiffness and viscosity and upper-limb inertia were quantified under various levels of muscle contraction in seven healthy human subjects. Through a cast attachment, the upper limb was perturbed in a precise pattern by a computer-controlled servomotor to manifest the dynamic properties of the joint. The recorded joint position and torque were used to estimate joint stiffness and viscosity and upper-limb inertia. With moderate muscle contraction, the stiffness and viscosity increased several fold. A stiffer shoulder joint associated with stronger muscle contraction made the shoulder more stable and protected it from potential injuries during strenuous tasks. Joint viscosity, especially the stronger viscous damping associated with more strenuous contraction, smoothed shoulder movement and stabilized the joint. From the control viewpoint, the glenohumeral joint responded to the central nervous system more quickly with increasing muscle contraction, which was useful during strenuous tasks. On the other hand, the central nervous system controlled stiffness and viscosity synchronously so that it dealt with only a nearly constant damping ratio of the joint over various levels of contraction, which simplified its task substantially. This approach quantified the dynamic and static properties of the shoulder under various levels of contraction more accurately and completely than a manual test, and it can potentially be used to evaluate changes in these properties caused by musculoskeletal injuries and their surgical treatments.

Adult↗
PubMed2000

Moment distribution among human elbow extensor muscles during isometric and submaximal extension.

To understand better how the central nervous system (CNS) distributes a joint moment among muscles, moment distribution among the three heads of the triceps and the anconeus muscles during isometric elbow extension was quantified in vivo and noninvasively. Electrical stimulation was used to activate an individual muscle selectively at various contraction levels, and the relationship between the peak M-wave amplitude and peak elbow extension moment was established across various contraction levels for each muscle. The relationship was then used to calibrate the corresponding EMG signal and determine moment distribution among the muscles during voluntary isometric elbow extension. Results showed that moment distribution among muscles was not proportional to the muscles' physiological cross-sectional areas (PCSA) and the CNS favored uniarticular muscles for the isometric task performed: the uniarticular lateral and medial heads of the triceps were dominant (contributing approximately 70-90% of the total elbow extension moment) and the anconeus contributed significantly, especially at the lower levels of elbow extension moment (up to approximately 15% of the extension moment). In contrast, the two-joint long head of the triceps contributed significantly less than the uniarticular heads of the triceps. While the absolute contributions of all the muscles increased with the total elbow extension moment, the relative contributions of the muscles may increase or decrease with the elbow extension moment. Cross-validation using fresh data (not used in determining the moment distribution) showed close match between the measured and predicted elbow extension moment except for trials in which fatigue became significant.

Elbow↗
PubMed2000

Hyperactive tendon reflexes in spastic multiple sclerosis: measures and mechanisms of action.

OBJECTIVE: To develop new measures of tendon reflexes and evaluate hyperactive reflexes in patients with spastic multiple sclerosis (MS). DESIGN: With the subject relaxed, a hand-held instrumented hammer was used to tap the patellar tendon and record the tapping force, while knee extension torque and quadriceps EMG were recorded isometrically as measures of the reflex response. SETTING: Research laboratory in a rehabilitation hospital. SUBJECTS: Ten spastic MS and 14 healthy subjects. MAIN OUTCOME MEASURES: Tendon tapping force (designated as system input), reflex torque (as output), their dynamic relationship (characterized as system parameters tendon reflex gain, contraction rate, and reflex loop delay), Ashworth scale, and tendon reflex scale. RESULTS: The system parameters provide more repeatable measures than do input or output parameters alone because they quantify the input and output simultaneously and dynamically. Compared with control subjects, MS patients had a significantly lower threshold in tapping force (p = .026), yet their evoked reflex torque was significantly higher (p = .033). Despite significant quadriceps weakness (p < .0001), MS patients had a significantly higher reflex gain (p = .0002) and contraction rate (p = .0002), and shorter reflex loop delay (p = .0046), indicating hyperexcitability of motoneurons and peripheral receptors, and indicating that relatively more of the muscle was activated reflexively, with greater recruitment of larger fast-twitch fibers. Both the reflex gain and rate measures correlated more closely with the Ashworth scale and tendon reflex scale than did the output measures, indicating their potential clinical value. CONCLUSIONS: With appropriate simplification, the method may be used in clinical practice to quantify more precisely the tendon jerk than is currently feasible with standard clinical tests.

Adult↗
PubMed2000

The clinical utility of measuring total PSA, PSA density, gamma-seminoprotein and gamma-seminoprotein/total PSA in prostate cancer prediction.

BACKGROUND: To evaluate whether serum total prostate-specific antigen (PSA), PSA density (serum total PSA level divided by prostate volume), gamma-seminoprotein and gamma-seminoprotein/total PSA ratio could predict prostate cancer (PCa) prior to biopsy. METHODS: A total of 316 consecutive patients who had undergone transrectal prostate biopsy and/or transurethral resection were examined. The prostate volume was determined by transrectal ultrasonography (TRUS) and the ability of the above-mentioned four variables to distinguish PCa from benign prostatic hyperplasia (BPH) was evaluated. RESULTS: PCa was detected in 61 cases. Receiver-operating characteristic (ROC) analysis revealed that both the PSA density and serum total PSA were the most useful predictors of PCa among the four variables. For the patients with a serum total PSA level of 4.1-10.0 ng/ml, PSA density was significantly more accurate than total PSA (p < 0.005). An optimum PSA density value of 0.18 was chosen as a cutoff because it showed the highest sum of sensitivity and specificity, 92 and 54%, respectively. Using this PSA density cutoff, the number of biopsies could have been reduced to 57 from 63% when compared with a PSA density of 0.15. CONCLUSIONS: PSA density was significantly more accurate than other variables in predicting PCa. To avoid unnecessary biopsies, the PSA density cutoff value of 0.18 would be recommendable for determining a prostate biopsy for Japanese males with a serum total PSA level of 4.1-10.0 ng/ml.

Aged↗
PubMed2000

Sprint training normalizes Ca(2+) transients and SR function in postinfarction rat myocytes.

Previous studies have shown that myocytes isolated from sedentary (Sed) rat hearts 3 wk after myocardial infarction (MI) undergo hypertrophy, exhibit altered intracellular Ca(2+) concentration ([Ca(2+)](i)) dynamics and abnormal contraction, and impaired sarcoplasmic reticulum (SR) function manifested as prolonged half-time of [Ca(2+)](i) decline. Because exercise training elicits positive adaptations in cardiac contractile function and myocardial Ca(2+) regulation, the present study examined whether 6-8 wk of high-intensity sprint training (HIST) would restore [Ca(2+)](i) dynamics and SR function in MI myocytes toward normal. In MI rats, HIST ameliorated myocyte hypertrophy as indicated by significant (P </= 0.05) decreases in whole cell capacitances [Sham-Sed 179 +/-12 (n = 20); MI-Sed 226 +/- 7 (n = 20); MI-HIST 183 +/- 11 pF (n = 19)]. HIST significantly (P < 0.0001) restored both systolic [Ca(2+)](i) [Sham-Sed 421 +/- 9 (n = 79); MI-Sed 350 +/- 6 (n = 70); MI-HIST 399 +/- 9 nM (n = 70)] and half-time of [Ca(2+)](i) decline (Sham-Sed 0. 197 +/- 0.005; MI-Sed 0.247 +/- 0.006; MI-HIST 0.195 +/- 0.006 s) toward normal. Compared with Sham-Sed myocytes, SR Ca(2+)-ATPase expression significantly (P < 0.001) decreased by 44% in MI-Sed myocytes. Surprisingly, expression of SR Ca(2+)-ATPase was further reduced in MI-HIST myocytes to 26% of that measured in Sham-Sed myocytes. There were no differences in calsequestrin expression among the three groups. Expression of phospholamban was not different between Sham-Sed and MI-Sed myocytes but was significantly (P < 0.01) reduced in MI-HIST myocytes by 25%. Our results indicate that HIST instituted shortly after MI improves [Ca(2+)](i) dynamics in surviving myocytes. Improvement in SR function by HIST is mediated not by increased SR Ca(2+)-ATPase expression, but by modulating phospholamban regulation of SR Ca(2+)-ATPase activity.

Animals↗