Objectively measured 24-hour activity profiles before and after total hip arthroplasty.

AIMS: The purpose of this exploratory study was to investigate if the 24-hour activity profile (i.e. waking activities and sleep) objectively measured using wrist-worn accelerometry of patients scheduled for total hip arthroplasty (THA) improves postoperatively. PATIENTS AND METHODS: A total of 51 THA patients with a mean age of 64 years (24 to 87) were recruited from a single public hospital. All patients underwent THA using the same surgical approach with the same prosthesis type. The 24-hour activity profiles were captured using wrist-worn accelerometers preoperatively and at 2, 6, 12, and 26 weeks postoperatively. Patient-reported outcomes (Hip Disability and Osteoarthritis Outcome Score (HOOS)) were collected at all timepoints except two weeks postoperatively. Accelerometry data were used to quantify the intensity (sedentary, light, moderate, and vigorous activities) and frequency (bouts) of activity during the day and sleep efficiency. The analysis investigated changes with time and differences between Charnley class. RESULTS: Patients slept or were sedentary for a mean of 19.5 hours/day preoperatively and the 24-hour activity pattern did not improve significantly postoperatively. Outside of sleep, the patients spent their time in sedentary activities for a mean of 620 minutes/day (sd 143) preoperatively and 641 minutes/day (sd 133) six months postoperatively. No significant improvements were observed for light, moderate, and vigorous intensity activities (p = 0.140, p = 0.531, and p = 0.407, respectively). Sleep efficiency was poor (< 85%) at all timepoints. There was no postoperative improvement in sleep efficiency when adjusted for medications (p > 0.05). Patient-reported outcome measures showed a significant improvement with time in all domains when compared with preoperative levels. There were no differences with Charnley class at six months postoperatively. However, Charnley class C patients were more sedentary at two weeks postoperatively when compared with Charnley class A patients (p < 0.05). There were no further differences between Charnley classifications. CONCLUSION: This study describes the 24-hour activity profile of THA patients for the first time. Prior to THA, patients in this cohort were inactive and slept poorly. This cohort shows no improvement in 24-hour activity profiles at six months postoperative. Cite this article: Bone Joint J 2019;101-B:415-425.

Biomechanical changes and recovery of gait function after total hip arthroplasty for osteoarthritis: a systematic review and meta-analysis.

OBJECTIVE: To determine the change in walking gait biomechanics after total hip arthroplasty (THA) for osteoarthritis (OA) compared to the pre-operative gait status, and to compare the recovery of gait following THA with healthy individuals. METHODS: Systematic review with meta-analysis of studies investigating changes in gait biomechanics after THA compared to (1) preoperative levels and (2) healthy individuals. Data were pooled at commonly reported time points and standardised mean differences (SMDs) were calculated in meta-analyses for spatiotemporal, kinematic and kinetic parameters. RESULTS: Seventy-four studies with a total of 2,477 patients were included. At 6 weeks postoperative, increases were evident for walking speed (SMD: 0.32, 95% confidence intervals (CI) 0.14, 0.50), stride length (SMD: 0.40, 95% CI 0.19, 0.61), step length (SMD: 0.41, 95% CI 0.23, 0.59), and transverse plane hip range of motion (ROM) (SMD: 0.36, 95% CI 0.05, 0.67) compared to pre-operative gait. Sagittal, coronal and transverse hip ROM was significantly increased at 3 months (SMDs: 0.50 to 1.07). At 12 months postoperative, patients demonstrated deficits compared with healthy individuals for walking speed (SMD: -0.59, 95% CI -1.08 to -0.11), stride length (SMD: -1.27, 95% CI -1.63, -0.91), single limb support time (SMD: -0.82, 95% CI -1.23, -0.41) and sagittal plane hip ROM (SMD: -1.16, 95% CI -1.83, -0.49). Risk of bias scores ranged from seven to 24 out of 26. CONCLUSIONS: Following THA for OA, early improvements were demonstrated for spatiotemporal and kinematic gait patterns compared to the pre-operative levels. Deficits were still observed in THA patients compared to healthy individuals at 12 months.

Tau protein: a possible prognostic factor in optic neuritis and multiple sclerosis.

BACKGROUND: Tau protein has been proposed as biomarker of axonal damage leading to irreversible neurological impairment in MS. CSF concentrations may be useful when determining risk of progression from ON to MS. OBJECTIVE: To investigate the association between tau protein concentration and 14-3-3 protein in the cerebrospinal fluid (CSF) of patients with monosymptomatic optic neuritis (ON) versus patients with monosymptomatic onset who progressed to multiple sclerosis (MS). To evaluate results against data found in a complete literature review. METHODS: A total of 66 patients with MS and/or ON from the Department of Neurology of Glostrup Hospital, University of Copenhagen, Denmark, were included. CSF samples were analysed for tau protein and 14-3-3 protein, and clinical and paraclinical information was obtained from medical records. RESULTS: The study shows a significantly increased concentration of tau protein in CSF from patients with relapsing-remitting MS and patients monosymptomatic at onset who progressed to MS, but interestingly no increased tau protein concentration in monosymptomatic ON. The concentration of tau protein was significantly correlated to Expanded Disability Status Scale score. No 14-3-3 protein was detected in any CSF sample. CONCLUSIONS: The results of this study invite further exploration of the possible role of tau protein as a prognostic factor to predict progression from ON to MS in future studies.

Prediction of skin sensitization potential using D-optimal design and GA-kNN classification methods.

Modelling of skin sensitization data of 255 diverse compounds and 450 calculated descriptors was performed to develop global predictive classification models that are applicable to whole chemical space. With this aim, we employed two automated procedures, (a) D-optimal design to select optimal members of the training and test sets and (b) k-Nearest Neighbour classification (kNN) method along with Genetic Algorithms (GA-kNN Classification) to select significant and independent descriptors in order to build the models. This methodology helped us to derive multiple models, M1-M5, that are stable and robust. The best among them, model M1 (CCR(train) = 84.3%, CCR(test) = 87.2% and CCR(ext) = 80.4%), is based on six neighbours and nine descriptors and further suggests that: (a) it is stable and robust and performs better than the reported models in literature, and (b) the combination of D-optimal design and GA-kNN classification approach is a very promising approach. Consensus prediction based on the models M1-M5 improved the CCR of training, test and external validation datasets by 3.8%, 4.45% and 3.85%, respectively, over M1. From the analysis of the physical meaning of the selected descriptors, it is inferred that the skin sensitization potential of small organic compounds can be accurately predicted using calculated descriptors that code for the following fundamental properties: (i) lipophilicity, (ii) atomic polarizability, (iii) shape, (iii) electrostatic interactions, and (iv) chemical reactivity.

Establishment of an H6N2 influenza virus lineage in domestic ducks in southern China.

Multiple reassortment events between different subtypes of endemic avian influenza viruses have increased the genomic diversity of influenza viruses circulating in poultry in southern China. Gene exchange from the natural gene pool to poultry has contributed to this increase in genetic diversity. However, the role of domestic ducks as an interface between the natural gene pool and terrestrial poultry in the influenza virus ecosystem has not been fully characterized. Here we phylogenetically and antigenically analyzed 170 H6 viruses isolated from domestic ducks from 2000 to 2005 in southern China, which contains the largest population of domestic ducks in the world. Three distinct hemagglutinin lineages were identified. Group I contained the majority of isolates with a single internal gene complex and was endemic in domestic ducks in Guangdong from the late 1990s onward. Group II was derived from reassortment events in which the surface genes of group I viruses were replaced with novel H6 and N2 genes. Group III represented H6 viruses that undergo frequent reassortment with multiple virus subtypes from the natural gene pool. Surprisingly, H6 viruses endemic in domestic ducks and terrestrial poultry seldom reassort, but gene exchanges between viruses from domestic ducks and migratory ducks occurred throughout the surveillance period. These findings suggest that domestic ducks in southern China mediate the interaction of viruses between different gene pools and facilitate the generation of novel influenza virus variants circulating in poultry.

The development and genetic diversity of H5N1 influenza virus in China, 1996-2006.

Since it was first detected in 1996, the Goose/Guangdong/1/1996 (Gs/GD) H5N1 influenza virus and its reassortants have spread to over 60 countries, with over 20 distinct genetic reassortants previously recognized. However, systematic analysis of their interrelationship and the development of genetic diversity have not been explored. As each of those reassortants was first detected in China, here 318 full-length H5N1 virus genomes isolated from 1996 to 2006 in this region were phylogenetically analyzed. Our findings revealed two major group reassortment events in 2001 and 2002 that were responsible for the generation of the majority of the 44 distinct Gs/GD genotypes identified, excepting those 1997 variants. Genotype replacement and emergence occurred continually, with 34 transient genotypes detected while only 10 variants were persistent. Two major replacements of predominant genotypes were also observed: genotype B replaced by Z in 2002 and then genotype Z replaced by the now predominant genotype V in 2005.

A novel presenilin 2 mutation (V393M) in early-onset dementia with profound language impairment.

BACKGROUND: Mutations in the Presenilin 2 gene (PSEN2) are rare causes of Alzheimer's disease (AD). Pathogenic mutations in the genes associated with autosomal dominant inherited AD have been shown to alter processing of the amyloid precursor protein (APP) resulting in a relative increase of the amount of Abeta42 peptide. METHODS AND RESULTS: We present a patient with neuropathologically confirmed early-onset AD characterized by profound language impairment. The patient was heterozygous for a novel missense mutation in exon 11 of the PSEN2 gene leading to a predicted amino acid substitution from valine to methionine in position 393, a conserved residue. However, in vitro expression of PSEN2 V393M cDNA did not result in detectable increase of the secreted Abeta42/40 peptide ratio. The mutation was not found in 384 control individuals tested. CONCLUSIONS: The possible pathogenic nature of the mutation is not clarified. We discuss the limitations of functional PSEN2 studies and the challenges associated with genetic counselling of family members at risk.

Identification of the progenitors of Indonesian and Vietnamese avian influenza A (H5N1) viruses from southern China.

The transmission of highly pathogenic avian influenza H5N1 virus to Southeast Asian countries triggered the first major outbreak and transmission wave in late 2003, accelerating the pandemic threat to the world. Due to the lack of influenza surveillance prior to these outbreaks, the genetic diversity and the transmission pathways of H5N1 viruses from this period remain undefined. To determine the possible source of the wave 1 H5N1 viruses, we recently conducted further sequencing and analysis of samples collected in live-poultry markets from Guangdong, Hunan, and Yunnan in southern China from 2001 to 2004. Phylogenetic analysis of the hemagglutinin and neuraminidase genes of 73 H5N1 isolates from this period revealed a greater genetic diversity in southern China than previously reported. Moreover, results show that eight viruses isolated from Yunnan in 2002 and 2003 were most closely related to the clade 1 virus sublineage from Vietnam, Thailand, and Malaysia, while two viruses from Hunan in 2002 and 2003 were most closely related to viruses from Indonesia (clade 2.1). Further phylogenetic analyses of the six internal genes showed that all 10 of those viruses maintained similar phylogenetic relationships as the surface genes. The 10 progenitor viruses were genotype Z and shared high similarity (>/=99%) with their corresponding descendant viruses in most gene segments. These results suggest a direct transmission link for H5N1 viruses between Yunnan and Vietnam and also between Hunan and Indonesia during 2002 and 2003. Poultry trade may be responsible for virus introduction to Vietnam, while the transmission route from Hunan to Indonesia remains unclear.

Establishment of influenza A virus (H6N1) in minor poultry species in southern China.

An H6N1 virus, A/teal/Hong Kong/W312/97 (W312), was isolated during the "bird flu" incident in Hong Kong in 1997. Genetic analysis suggested that this virus might be the progenitor of the A/Hong Kong/156/97 (HK/97) H5N1 virus, as seven of eight gene segments of those viruses had a common source. Continuing surveillance in Hong Kong showed that a W312-like virus was prevalent in quail and pheasants in 1999; however, the further development of H6N1 viruses has not been investigated since 2001. Here we report influenza virus surveillance data collected in southern China from 2000 to 2005 that show that H6N1 viruses have become established and endemic in minor poultry species and replicate mainly in the respiratory tract. Phylogenetic analysis indicated that all H6N1 isolates had W312-like hemagglutinin and neuraminidase genes. However, reassortment of internal genes between different subtype virus lineages, including H5N1, H9N2, and other avian viruses, generated multiple novel H6N1 genotypes in different types of poultry. These novel H6N1/N2 viruses are double, triple, or even quadruple reassortants. Reassortment between a W312-like H6N1 virus and an A/quail/Hong Kong/G1/97 (HK/97)-like H9N2 virus simultaneously generated novel H6N2 subtype viruses that were persistent in poultry. Molecular analyses suggest that W312-like viruses may not be the precursors of HK/97 virus but reassortants from an HK/97-like virus and another unidentified H6 subtype virus. These results provide further evidence of the pivotal role of the live poultry market system of southern China in generating increased genetic diversity in influenza viruses in this region.

The genesis and evolution of H9N2 influenza viruses in poultry from southern China, 2000 to 2005.

H9N2 influenza viruses have become established in terrestrial poultry in different Asian countries over the last 2 decades. Our previous study demonstrated that quail harbor increasingly diverse novel H9N2 reassortants, including both Chicken/Beijing/1/94 (Ck/Bei-like) and Quail/Hong Kong/G1/97 (G1-like) viruses. However, since 1999, the genesis and evolution of H9N2 viruses in different types of poultry have not been investigated systematically. In the present study, H9N2 viruses isolated from chickens, ducks, and other minor poultry species were characterized genetically and antigenically. Our findings demonstrate that Ck/Bei-like H9N2 viruses have been introduced into many different types of poultry in southern China, including quail, partridges, chukar, pheasant, guinea fowl, and domestic ducks, while G1-like viruses were commonly detected in quail, less frequently detected in other minor poultry species, and not detected in chickens and ducks. Genetic analysis revealed 35 genotypes of H9N2 viruses, including 14 novel genotypes that have not been recognized before. Our results also suggested that two-way interspecies transmission exists between different types of poultry. Our study demonstrates that the long-term cocirculation of multiple virus lineages (e.g., H5N1 and H9N2 viruses) in different types of poultry has facilitated the frequent reassortment events that are mostly responsible for the current great genetic diversity in H9N2 and H5N1 influenza viruses in this region. This situation favors the emergence of influenza viruses with pandemic potential.

Phylogeny of Rosellinia capetribulensis sp. nov. and its allies (Xylariaceae).

A new Rosellinia species, R. capetribulensis isolated from Calamus sp. in Australia is described. R. capetribulensis is characterized by perithecia immersed within a carbonaceous stroma surrounded by subiculum-like hyphae, asci with large, barrel-shaped amyloid apical apparatus and large dark brown spores. Morphologically, R. capetribulensis appears to be similar to R. bunodes, R. markhamiae and R. megalospora. To gain further insights into the phylogeny of this new taxon we analyzed the ITS-5.8S rDNA using maximum parsimony and likelihood methods. In addition, a morphological dataset also was analyzed phylogenetically to investigate possible affinities. ITS rDNA based phylogenies reveal that R. capetribulensis is closely related to other Rosellinia species showing closest affinity to R. arcuata, RL necatrix and R. pepo. However, analysis of R. capetribulensis forms an unsupported branch sister to these taxa. Results from the morphological matrix indicate a close morphological affinity to members of Rosellinia subgenus Rosellinia. Despite that ITS rDNA and morphological analyses present difficulties in constructing a proper phylogenetic framework among Rosellinia and allied genera, there is sufficient evidence to support the establishment of the new taxon in the genus Rosellinia. The morphological similarities and differences between R. capetribulensis and allied genera such as Astrocystis and Entoleuca are also briefly discussed.

Neuroendocrine properties of intrinsic cardiac adrenergic cells in fetal rat heart.

Intrinsic cardiac adrenergic (ICA) cells in developing rat heart constitute a novel adrenergic signaling system involved in cardiac regulation. Regulatory mechanisms of ICA cells remain to be defined. Immunohistochemical study of fetal rat hearts demonstrated ICA cells with catecholamine biosynthetic enzyme tyrosine hydroxylase (TH) and phenylethanolamine N-methyltransferase (PNMT). The mRNA of TH and PNMP was also detected in fetal rat hearts before sympathetic innervation. Immunoreactivity of norepinephrine transporter (NET) was localized to ICA cells in rat heart tissue and primary cell culture. For the functional study, the activity of intracellular Ca2+ concentration ([Ca2+]i) transients was quantified by a ratio fluorescent spectrometer in cultured ICA cells and myocytes. ICA cells generated spontaneous [Ca2+]i transients that were eliminated by tetrodotoxin or Ca(2+)-free solutions and showed greatly reduced amplitude with the addition of L-type Ca2+ channel blocker nifedipine. [3H]norepinephrine studies demonstrate release and uptake of norepinephrine. Functional interaction between catecholamines produced by the ICA cells and cocultured myocytes was evident by the effect of the beta-adrenergic blocker atenolol eliciting a dose-dependent reduction in the amplitude and frequency of [Ca2+]i transients of beating myocytes. Hypoxia inhibited [Ca2+]i transient activity of ICA cells, which subsequently produced a reoxygenation-mediated rebound augmentation of [Ca2+]i transients. We conclude that ICA cells are capable of catecholamine synthesis, release, and uptake. They generate spontaneous [Ca2+]i transient activity that can be regulated by oxygen tension. ICA cells may provide an alternative adrenergic supply to maintain cardiac contractile and pacemaker function at rest and during stress in the absence of sympathetic innervation.

Bioactivities of the leaf essential oil of Curcuma longa (var. ch-66) on three species of stored-product beetles (Coleoptera).

Essential oil extracted from the leaves of turmeric, Curcuma longa L., was investigated for contact and fumigant toxicity and its effect on progeny production in three stored-product beetles, Rhyzopertha dominica F. (lesser grain borer), Sitophilus oryzae L. (rice weevil), and Tribolium castaneum Herbst (red flour beetle). Oviposition-deterrent and ovicidal actions of C. longa leaf oil were also evaluated against T. castaneum. The oil was insecticidal in both contact and fumigant toxicity assays. The adults of R. dominica were highly susceptible to contact action of C. longa leaf oil, with LD50 value of 36.71 microg/mg weight of insect, whereas in the fumigant assay, adults of S. oryzae were highly susceptible with LC50 value of 11.36 mg/liter air. Further, in T. castaneum, the C. longa oil reduced oviposition and egg hatching by 72 and 80%, respectively at the concentration of 5.2 mg/cm2. At the concentration of 40.5 mg/g food, the oil totally suppressed progeny production of all the three test insects. Nutritional indices indicate >81% antifeedant action of the oil against R. dominica, S. oryzae and T castaneum at the highest concentration tested.

Modulation of the inflammatory response in the cardiomyocyte and macrophage.

Numerous cardiac disease processes have been linked to the overproduction of nitric oxide (NO) via inducible nitric oxide synthase (iNOS) in the cardiovascular system. Chronic and acute exposure to hyperphysiologic levels of NO has been suggested as an agent in chronic transplant rejection, various cardiomyopathies, reperfusion injury, and the inflammatory state following cardiopulmonary bypass. Proinflammatory cytokines and inflammatory cell types, such as macrophage and neutrophils, have also been implicated in the pathophysiology associated with the previously mentioned syndromes. Previous work by this group has shown that lipopolysaccharide (LPS) in combination with tumor necrosis factor-alpha (TNF-alpha) can increase iNOS expression and the production of NO in macrophage. With this in mind, we hypothesized that increased iNOS expression and NO production generated by LPS and TNF-alpha in the macrophage could be mimicked in the cardiomyocyte and potentially account for some aspect of the cardiac dysfunction attributed to NO. Furthermore, this increased expression of iNOS and NO production could be returned to control using the glucocorticoid, dexamethasone, a known iNOS transcription blocker. Using fetal rat cardiomyocytes in primary culture cell line and a murine macrophage cell line, RAW 264.7, the expression of iNOS was quantified with specific FITC-conjugated antibodies using fluorescence activated cell sorter (FACS) and NO production with a Bioxytech nitric oxide spectrophotometric assay. The myocytes and macrophage were separated into three groups, Control, TNF + LPS, and (+) Dexamethasone. The control groups received no TNF or LPS or dexamethasone, TNF + LPS groups received TNF-alpha and LPS for 8 hours with no dexamethasone, and the (+) Dexamethasone groups were pretreated with dexamethasone for 8 hours and stimulated with TNF-alpha and LPS along with a second 8-hour treatment of dexamethasone. The macrophage cell groups treated with TNF-alpha and LPS showed a 335% increase over control in iNOS expression, and NO production was increased 494% from control. Macrophage treated with dexamethasone experienced an attenuation of iNOS expression of 200% toward control from stimulated levels and 202% decrease in NO production from stimulated levels toward control. Cardiomyocytes exhibited no statistically significant change in the expression of iNOS or NO production with stimulation or dexamethasone treatments. In conclusion, iNOS and NO were elevated in macrophage, which can be blunted in the presence of dexamethasone in the macrophage. Curiously, iNOS could not be stimulated in the cardiomyocyte, suggesting inflammatory cells may be largely responsible for the elevated iNOS and NO experienced in some cardiovascular diseases. The clinical relevance of this study is the introduction of specific iNOS inhibitors into the cardiopulmonary bypass circuit could serve as a potential mechanism for modulating the inflammatory response surrounding cardiopulmonary bypass. Likewise, therapeutic glucocorticoid administration could improve outcomes for patients with inflammatory cardiovascular disease states related to elevated NO production.

Cloning and characterization of P110, a novel small nucleolar U3 ribonucleoprotein, expressed in early development.

We report the cloning of a BrdU-sensitive transcript of 4.1 kb from an immortalized quail heart cell line containing an open reading frame of 940 amino acids (110 kDa, pI approximately 5.18). The mRNA encoding P110 appears in the heart and neural tube by 36 h of avian development, at a time when these organs are rapidly developing. Analysis of the DNA-deduced protein sequence revealed a bipartite nuclear localization signal, and a highly charged domain rich in both acidic and basic residues. Immunofluorescent staining with polyclonal antibodies raised against a P110 peptide localized the protein to the nucleolus of avian and mammalian cells. Although database search showed significant homology with an uncharacterized cDNA from human brain and several human and mouse Expressed Sequence Tags, there was no close homology to known nucleolar proteins. Immunoprecipitation of P110 from cell sonicates revealed it contained U3 small nucleolar RNA, but no significant amounts of other box C/D small nucleolar RNAs. These data suggest that P110 is one of the U3 small nucleolar ribonucleoproteins that are involved in rRNA processing.

Expression of alpha and beta integrins during terminal differentiation of cardiomyocytes.

BACKGROUND: In the myocardium, myocyte cell division is irreversibly blocked shortly after birth. The signal that initiates cell cycle withdrawal is unknown. The purpose of this study was to relate changes in expression of beta1 integrin and its associated alpha subunits to cardiomyocyte cell cycle progression during the fetal-to-neonatal developmental transition in rat. METHODS AND RESULTS: The developmental expression pattern and function of beta 1 integrin and several of its associated alpha subunits were examined using reverse transcription (RT) polymerase chain reaction (PCR) and beta 1 blocking antibodies. During the fetal to neonatal transition, a dramatic shift occurred in the levels of beta1 and alpha isoforms. At the 17-day fetal stage only beta 1A was present, which remained relatively constant until immediately after birth then decreased by 30% at the adult stage. By contrast, beta 1D appeared at fetal day 18, increased at neonatal day 2, and afterwards remained constant. This resulted in a ratio of beta 1A to beta 1D of about 1:1 in the adult heart. The integrin beta 1-associated subunits, alpha 3, alpha 6, and alpha 7, were expressed at extremely low levels in 17-day fetal cardiomyocytes. After birth alpha 3 and alpha 6 transiently increased at the 2-day neonatal stage, while alpha 7 isoforms B, C, and X2 progressively increased to the adult stage. Unlike skeletal muscle cells, fluorescence-activated cell sorting analysis (FACS) showed no down regulation of the alpha 5 beta 1 fibronectin receptor during cell cycle withdrawal. Treatment of cultured cardiomyocytes with beta1 blocking antibody inhibited the cell cycle in fetal but not in neonatal cells. CONCLUSION: These results suggest that progression through the cardiomyocyte cell cycle may be dependent upon cell attachment via integrin beta1 and correlate with changes that occur in beta1 spliced variants and their respective alpha isoforms.

Hydrogen peroxide dose dependent induction of cell death or hypertrophy in cardiomyocytes.

Cardiomyocyte hypertrophy and cell death are often observed in the end stages of heart failure. The triggers of these two cellular processes are not known under most pathological conditions. Oxidants are by-products of aerobic metabolism. The level of oxidants increases as a result of ischemic reperfusion. Using H9C2 and primary cultured neonatal rat cardiomyocytes, we found that a 2-h pulse treatment with H(2)O(2) at 250 microM or lower caused activation of DEVD sequence specific caspases. The activity of DEVD-ase peaked with 200 microM H(2)O(2) at 24 h. While a fraction of the cells detached and showed nuclear condensation, the majority of the cells (>55%) survived the treatment and appeared to enlarge when cultured for 5 days. These cells showed increases in cell surface area, cell volume, and protein content. With 200 microM H(2)O(2), treated cells appeared to be six times bigger in volume and contained three times more protein per cell than untreated cells. The enlarged cells showed enhanced actin stress fibers and disrupted myofibrils. Our data indicate that while H(2)O(2) can cause cell death, the surviving cardiomyocytes undergo hypertrophy.

IGF I induction of p53 requires activation of MAP kinase in cardiac muscle cells.

The aim of this study was to investigate whether IGF I induction of p53 expression and p21 promoter require activation of MAP kinase in cardiac muscle cells. Compared to cardiomyocytes transfected with control vector, activation of MAP kinase by IGF I was decreased by approximately 60-70% in the cells transfected with dominant negative MAP kinase Y185. Transfection with Y185 also resulted in decreased induction of p53 mRNA by IGF I (70% reduction). In the cells transfected with a wildtype p21WAF1/CIP1 promoter construct, activation of luciferase reporter gene by IGF I was decreased in the cells co-transfected with Y185. To further confirm these findings, cells were preincubated with PD98059, a specific MAP kinase kinase inhibitor. As expected, PD98059 inhibited induction of p53 mRNA and p21WAF1/CIP1 promoter by IGF I. These data indicate that transcriptional activation of p53 and p21WAF1/CIP1 by IGF I involves MAP kinase pathway in cardiomyocytes, and thus link MAP kinase to negative modulation of the cell cycle in cardiac muscle cells.

Structure, regulation and function of avian glypican.

Glypicans are a group of membrane-bound heparan sulfate proteoglycans (HSPG) that are tissue specific and developmentally regulated. Transcripts for avian glypican are found in endocardial cushions, limb buds, somites and forebrain of early chick embryos. Since avian glypican is not well characterized, the cellular localization, regulation of expression, and possible function during cardiac development have been studied. A polyclonal antibody was raised against a 20-amino acid peptide corresponding to an antigenic sequence within avian glypican core protein. The antibody recognized the expressed core protein in bacterial lysates and the endogenous HSPG in the proteoglycan fraction from chick forebrain. Immunolocalization studies indicated that the core protein is associated with cell membranes. The level of mRNA for avian glypican in MEQC (myc embryonic quail cardiomyocytes) grown in medium containing 10% fetal calf serum was compared to the message levels in cells grown without serum for 3 days. By Northern analysis, glypican transcripts were increased markedly after serum starvation. Up-regulation of glypican transcripts by serum withdrawal was partially prevented by addition of TGFbeta-1 and bFGF, suggesting that these growth factors may regulate its expression. MEQC cells deprived of serum migrated into clumps that could be blocked by an antisense OND (oligodeoxynucleotide) to the mRNA encoding the avian glypican. The same antisense OND inhibited the migration of endothelial cells from chick tubular heart explants over the surface of collagen gels. These results indicate that avian glypican may play a role in cell migration during development of endocardial cushions.