Search

Developmental methylmercury (MeHg) exposure can have lasting consequences on neural development and motor function across the lifespan. Recent evidence for MeHg targeting of myogenic pathways has drawn attention to the possibility that developing skeletal muscle plays a role in the motor deficits stemming from early life MeHg exposure. In this study we examined a potential role for muscle in influencing MeHg developmental toxicity in offspring of female mice exposed to MeHg via drinking water. Dams had access to 0, 0.5 or 5.0 ppm MeHg chloride in drinking water from two weeks prior to mating through weaning. Blood, brain and muscle tissue was harvested from dams at weaning and pups at postnatal days (PND) 6, 21 and 60 for analysis of total Hg. Muscle tissue sections were examined with histological stains. Behavioral testing of offspring was conducted at PND 60 and included locomotor activity, inverted screen, grip strength and rotarod tests to assess motor function. Total Hg (tHg) levels in dam muscles at weaning were 1.7–3-fold higher than Hg levels in blood or brain. In PND6 male and female pups, muscle and brain tHg levels were 2 to 4-fold higher than blood tHg. Brain tHg levels decreased more rapidly than muscle tHg levels between PND 6 and 21. Premised on modeling of growth dilution, brain tissue demonstrated an elimination of tHg while muscle tissue exhibited a net uptake of tHg between PND 6 and 21. Despite overall elevated Hg levels in developing muscle, no gross morphological or cytological phenotypes were observed in muscle at PND 60. At the higher MeHg dose, grip strength was reduced in both females and males at PND 60, whereas only male specific deficits were observed in locomotor activity and inverted screen tests with marginally significant deficits on rotarod. These findings highlight a potential role for developing skeletal muscle in mediating the neuromuscular insult of early life MeHg exposure.

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal-dominant myopathy characterized by slowly progressive skeletal muscle weakness and wasting. While a regenerative response is often provoked in many muscular dystrophies, little is known about whether a regenerative response is regularly elicited in FSHD muscle, prompting this study. For comparison, we also examined the similarly slowly progressing myotonic dystrophy type 2 (DM2). To first investigate regeneration at the transcriptomic level, we used the 200 human gene Hallmark Myogenesis list. This myogenesis biomarker was elevated in FSHD and control healthy myotubes compared to their myoblast counterparts, so is higher in myogenic differentiation. The myogenesis biomarker was also elevated in muscle biopsies from most independent FSHD, DM2 or Duchenne muscular dystrophy (DMD) studies compared to control biopsies, and on meta-analysis for each condition. In addition, the myogenesis biomarker was a robust binary discriminator of FSHD, DM2 and DMD from controls. We also analysed muscle regeneration at the protein level by immunolabelling muscle biopsies for developmental myosin heavy chain. Such immunolabelling revealed one or more regenerating myofibres in 76% of FSHD muscle biopsies from quadriceps and 91% from tibialis anterior. The mean proportion of regenerating myofibres per quadriceps biopsy was 0.48%, significantly less than 1.72% in the tibialis anterior. All DM2 muscle biopsies contained regenerating myofibres, with a mean of 1.24% per biopsy. Muscle regeneration in FSHD was correlated with the pathological hallmarks of fibre size variation, central nucleation, fibrosis and necrosis/regeneration/inflammation. In summary, the regenerative response in FSHD muscle biopsies correlates with the severity of pathology.

BackgroundFacioscapulohumeral dystrophy (FSHD) is an inherited muscular dystrophy clinically characterised by muscle weakness starting with the facial and upper extremity muscles. A disease model has been developed that postulates that failure in somatic repression of the transcription factor DUX4 embedded in the D4Z4 repeat on chromosome 4q causes FSHD. However, due to the position of the D4Z4 repeat close to the telomere and the complex genetic and epigenetic aetiology of FSHD, there is ongoing debate about the transcriptional deregulation of closely linked genes and their involvement in FSHD.MethodDetailed genetic characterisation and gene expression analysis of patients with clinically confirmed FSHD and control individuals.ResultsIdentification of two FSHD families in which the disease is caused by repeat contraction and DUX4 expression from chromosome 10 due to a de novo D4Z4 repeat exchange between chromosomes 4 and 10. We show that the genetic lesion causal to FSHD in these families is physically separated from other candidate genes on chromosome 4. We demonstrate that muscle cell cultures from affected family members exhibit the characteristic molecular features of FSHD, including DUX4 and DUX4 target gene expression, without showing evidence for transcriptional deregulation of other chromosome 4-specific candidate genes.ConclusionThis study shows that in rare situations, FSHD can occur on chromosome 10 due to an interchromosomal rearrangement with the FSHD locus on chromosome 4q. These findings provide further evidence that DUX4 derepression is the dominant disease pathway for FSHD. Hence, therapeutic strategies should focus on DUX4 as the primary target.

Facioscapulohumeral muscular dystrophy, known in genetic forms FSHD1 and FSHD2, is associated with D4Z4 repeat array chromatin relaxation and somatic derepression of DUX4 located in D4Z4. A complete copy of DUX4 is present on 4qA chromosomes, but not on the D4Z4-like repeats of chromosomes 4qB or 10. Normally, the D4Z4 repeat varies between 8 and 100 units, while in FSHD1 it is only 1-10 units. In the rare genetic form FSHD2, a combination of a 4qA allele with a D4Z4 repeat size of 8-20 units and heterozygous pathogenic variants in the chromatin modifier SMCHD1 causes DUX4 derepression and disease. In this study, we identified 11/79 (14%) FSHD2 patients with unusually large 4qA alleles of 21-70 D4Z4 units. By a combination of Southern blotting and molecular combing, we show that 8/11 (73%) of these unusually large 4qA alleles represent duplication alleles in which the long D4Z4 repeat arrays are followed by a small FSHD-sized D4Z4 repeat array duplication. We also show that these duplication alleles are associated with DUX4 expression. This duplication allele frequency is significantly higher than in controls (2.9%), FSHD1 patients (1.4%) and in FSHD2 patients with typical 4qA alleles of 8-20 D4Z4 units (1.5%). Segregation analysis shows that, similar to typical 8-20 units FSHD2 alleles, duplication alleles only cause FSHD in combination with a pathogenic variant in SMCHD1. We conclude that cis duplications of D4Z4 repeats explain DUX4 expression and disease presentation in FSHD2 families with unusual long D4Z4 repeats on 4qA chromosomes.

Introduction: As we move toward planning for clinical trials in facioscapulohumeral muscular dystrophy (FSHD), a better understanding of the clinical relationship with morphological changes in FSHD muscle biopsies will be important for stratifying patients and understanding post-therapeutic changes in muscle. Methods: We performed a prospective cross-sectional study of quadriceps muscle biopsies in 74 genetically confirmed FSHD participants (64 with FSHD type 1 and 10 with FSHD type 2). We compared a 12-point muscle pathology grade to genetic mutation, disease severity score, and quantitative myometry. Results: Pathology grade had moderate correlations with genetic mutation (rho = –0.45, P

The teaching of literature in English language classes is an issue that can draw mixed reactions from English language teachers.

Background: Posited pathological mechanisms in Facioscapulohumeral Muscular Dystrophy (FSHD) include activation in somatic tissue of normally silenced genes, increased susceptibility to oxidative stress, and induction of apoptosis. Objective: To determine the histopathological changes in FSHD muscle biopsies and compare to possible pathological mechanisms of disease. Methods: We performed a cross-sectional study on quadriceps muscle biopsies from 32 genetically confirmed FSHD participants, compared to healthy volunteers and myotonic dystrophy type 1 as disease controls. Biopsies were divided into groups to evaluate apoptosis rates, capillary density, myonuclear and satellite cell counts. Results: Apoptosis rates were increased in FSHD (n = 10, 0.74% ) compared to myotonic dystrophy type 1 (n = 10, 0.14% , P = 0.003) and healthy volunteers (n = 14, 0.13% , P = 0.002). Apoptosis was higher in FSHD patients with the smallest residual D4Z4 fragments. Capillary density was decreased in FSHD1 (n = 10, 316 capillaries/mm2) compared to healthy volunteers (n = 15, 448 capillaries/mm2, P = 0.001). No differences were seen in myonuclear or satellite cell counts. Conclusions: Preliminary evidence for increased apoptosis rates and reduced capillary density may reflect histopathological correlates of disease activity in FSHD. The molecular-pathological correlates to these changes warrants further investigation.

As we move toward planning for clinical trials in facioscapulohumeral muscular dystrophy (FSHD), a better understanding of the clinical relationship with morphological changes in FSHD muscle biopsies will be important for stratifying patients and understanding post-therapeutic changes in muscle.We performed a prospective cross-sectional study of quadriceps muscle biopsies in 74 genetically confirmed FSHD participants (64 with FSHD type 1 and 10 with FSHD type 2). We compared a 12-point muscle pathology grade to genetic mutation, disease severity score, and quantitative myometry.Pathology grade had moderate correlations with genetic mutation (rho = -0.45, P0.001), clinical severity score (rho = 0.53, P0.001), disease duration (rho = 0.31, P = 0.03), and quantitative myometry (rho = -0.47, P0.001). We found no difference in the frequency of inflammation between FSHD types 1 and 2.The pathology grade of quadriceps muscle may be a useful marker of disease activity in FSHD, and it may have a role in stratification for future clinical trials.

We investigated the associations of baseline epidermal nerve fiber (ENF) densities and morphology (percent ENF swellings) and quantitative sensory testing (QST) with clinically defined human immunodeficiency virus (HIV)-associated distal polyneuropathy (DSP) and whether these measures are predictive of development of symptomatic DSP over time. Fifty-seven HIV-infected subjects with and without DSP and 19 controls participated. Mean ENF densities were lower at the distal leg and proximal thigh in asymptomatic or symptomatic DSP than in controls. Mean ENF densities did not differ significantly among the HIV groups. Percent ENF swellings was higher in patients with symptomatic DSP than controls at the distal leg, and was also greater at the proximal thigh in patients with asymptomatic or symptomatic DSP than in controls. The percent ENF swellings at the distal leg correlated with the thresholds for both minimal (HP 0.5) and intermediate (HP 5.0) heat pain (HP) intensity. A higher percent ENF swellings in the distal leg [hazard ratio (HR) 1.16, 95% CI 1.02-1.31] and HP 0.5 thresholds (HR 1.03, 95% CI 1.01-1.05) were the only two measures associated with a shorter time to development of symptomatic DSP. Quantitation of ENF swellings and heat pain thresholds deserve further study as predictors of symptomatic neuropathy.

Myotonic dystrophy type 1 (DM1) and type 2 (DM2) are caused by genomic expansions of CTG or CCTG repeats. When transcribed, these mutations give rise to repeat expansion RNAs that form nuclear inclusions and compromise the function of myonuclei. Here, we have used in situ hybridization and immunofluorescence to compare DM1 and DM2 and search for proteins that associate with the RNA nuclear (ribonuclear) inclusions. Although muscle disease is generally more severe in DM1, the ribonuclear inclusions were 8- to 13-fold more intense in DM2, implying greater amounts of repeat expansion RNA. Expression of repeat expansion RNA in myoblasts has been implicated in the pathogenesis of congenital DM1. However, we found that repeat expansion RNA is also expressed in myoblasts in DM2, a disorder that has not been associated with a congenital phenotype. Of 10 putative CUG binding proteins tested for colocalization with mutant RNA, only proteins in the muscleblind family were recruited into ribonuclear inclusions. Previous studies have shown activation of the protein kinase, PKR, by expanded CUG repeats in vitro. However, breeding experiments utilizing PKR knockout mice indicate that this kinase is not required for disease pathogenesis in a transgenic mouse model of DM1. We conclude that ribonuclear inclusions are a key feature of the muscle pathology in DM and that sequestration of muscleblind proteins may have a direct role in the disease process.

Myotonic dystrophy (DM), the most common form of muscular dystrophy in adult humans, results from expansion of a CTG repeat in the 3′ untranslated region of the DMPK gene. The mutant DMPK messenger RNA (mRNA) contains an expanded CUG repeat and is retained in the nucleus. We have expressed an untranslated CUG repeat in an unrelated mRNA in transgenic mice. Mice that expressed expanded CUG repeats developed myotonia and myopathy, whereas mice expressing a nonexpanded repeat did not. Thus, transcripts with expanded CUG repeats are sufficient to generate a DM phenotype. This result supports a role for RNA gain of function in disease pathogenesis.

Objective: To investigate whether serially assessed epidermal nerve fiber (ENF) density and quantitative sensory thresholds (QSTs) are associated with the clinical transition from HIV infection with no neuropathy or asymptomatic neuropathy to symptomatic distal sensory neuropathy (SDSP). Background: Identifying predictors of transition to SDSP would enable identification of subjects at enhanced risk for development of HIV-SDSP and facilitate intervention studies with the ultimate goal of disease prevention. Asymptomatic signs of sensory dysfunction in the feet have been shown to be weakly predictive of SDSP; however, bedside evaluation of small sensory fibers is limited. Abnormality of these fibers may play an important role in the genesis of SDSP. Methods: Fifty-eight HIV-infected subjects underwent serial clinical, virologic, immunologic, skin biopsy, and QST assessments. Cox proportional hazards modeling was used to examine the associations of serial ENF density and QST assessments with the risk of development of SDSP among the subset of 26 subjects who had asymptomatic or no neuropathy at study entry. Results: Median follow-up was 2.9 years (range 6 months to 4.5 years) during which 19 of 26 subjects transitioned to SDSP. Using a model where ENF density and QST measures from the study visit before potential transition were examined, a lower leg ENF density, a higher cooling threshold, and a higher heat pain threshold for minimal pain (HP 0.5) were associated with a greater risk of SDSP in univariate analyses. In multiple regression analyses, leg ENF density but not QST measures were significantly associated with SDSP. A leg ENF density of 10 fibers/mm or less conferred a 14-fold greater risk of SDSP than a leg ENF density greater than 10 fibers/mm. Conclusions: Measures of small sensory fibers (leg epidermal nerve fiber density, cooling and heat pain thresholds) seem to be associated with transition to symptomatic HIV-associated distal sensory neuropathy 6 to 12 months later.

AT&T CallVantageSM service is a consumer broadband voice-over-Internet-protocol (VoIP) service. Its feature server has a component-based architecture. This paper is a brief report on our experience with building and deploying advanced telecommunication features using component-based technology.

The fundamental studies of metallic nanoparticles embedded in various host materials have been made. The host-guest interaction causes the shapes of embedded nanoparticles, and the surface plasmon resonances of the metallic nanoparticles are affected by the host materials. The control of the surface plasmon resonance condition is a challenging question. We will discuss the interface effect of the systems where gold nanoparticles were fabricated between materials of MgO and SiO2.

In the PhoneMan research project we are exploring IP-based telephony control, new telephony interfaces, and non-traditional ways of merging telephony, messaging and alerting. The PhoneMan application allows complete control and monitoring of an ISDN desktop phone from a local PC and remotely from the web. Current features include enhanced screen pops, which can be configured to query local or remote directories, including corporate directories and public white page services, and email call notification, which allows remote call alerting, call logging and active management of personal call histories. User reactions to the initial release of this application, based on in-person interviews and a web-based survey, reveal the novel use of email call logs as active call reminders and email messages as phone event triggers.

During the past decade there has been a marked shift in emphasis on air pollution problems. Instead of focusing on short or episodic problems of a local nature, significant interest has recently been directed toward the degradation of regional air quality and related problems caused by the transport of atmospheric pollutants from upwind emission sources over long distances. Even the phenomenon of photochemical smog, in the past considered an urban problem, has taken on a regional character. High ozone concentrations exceeding air quality standards have been observed over widespread rural areas located downwind of major metropolitan centers in the eastern United States, according to several reports (e.g., Wolff et al., 1977). Such occurrences have been observed in other areas of the United States and in western Europe (e.g., Fehsenfeld et al., 1983; Hov, Isaksen, and Hesstvedt, 1978).

A prospective study of 34 patients undergoing total hip replacement was done to determine whether homologous erythrocyte transfusion causes postoperative immunosuppression. In the transfused patient group (14 patients), there was a reduction in CD3+ and CD3+4+ cell numbers at Day 2, returning to preoperative levels by Day 7. In contrast, in the untransfused patient group (20 patients), there was no significant depression in these lymphocyte subgroups at Day 2 and an increase in total lymphocyte, CD3+, CD3+4+, and CD3+4-8- cell numbers at Day 7. In both patient groups there was postoperative leukocytosis, granulocytosis, and monocytosis at Days 2 and 7, with no significant change in postoperative B (CD19+) cell numbers, natural killer cells, or the minor T cell populations of CD3+4+8+ and CD3+25+. The lymphocyte functional test of Candida recall was significantly impaired at Day 7 in the transfused patient group, where Candida recall is a memory T cell response to an antigen extracted from the yeast Candida Albicans. These findings suggest that homologous erythrocyte transfusion after hip replacement surgery causes cell mediated immune suppression. The main clinical implication of the current study is that perioperative homologous erythrocyte transfusion may place patients at greater risk of infectious complications, including infection of the prosthesis.

A mathematical model of atmospheric optics was developed to predict the nighttime sky-glow impacts of a proposed nuclear waste repository in a national park. The prediction performance of the Night-Sky-Glow Model was evaluated to the extent possible with existing data. The model was applied to the proposed facility from several viewpoints within the park and the potential for normal perception of the calculated night glow and the potential of the night glow to obscure starlight were estimated.

Kato (1965) and Morris (1967) have reported correlations between stationary Rod-and-frame Tests (RFT; Witkin, Lewis, Hertzman, Machover, Meissner, & Wapner, 1954) and portable versions of their own design of .77 and .74, respectively. However, Vaught (1969) reports a correlation between a commercially available version and a stationary RFT of .44 for men, .41 for women, and .46 over-all.