Experimental muscle pain results in reorganization of coordination among trapezius muscle subdivisions during repetitive shoulder flexion

The aim of the study was to examine the effect of experimental unilateral upper trapezius muscle pain on the relative activation of trapezius muscle subdivisions bilaterally during repetitive movement of the upper limb. Surface EMG signals were detected from nine healthy subjects from the upper, middle and lower divisions of trapezius during a repetitive bilateral shoulder flexion task. Measurements were performed before and after injection of 0.5 ml hypertonic (pain condition) and isotonic (control) saline into the upper division of the right trapezius muscle in two experimental sessions. On the painful side, upper trapezius showed decreased EMG amplitude (average rectified value, ARV) and lower trapezius increased ARV throughout the entire task following the injection of hypertonic saline (40.0 ± 22.2 vs. 26.0 ± 17.4 μV, and 12.5 ± 7.6 vs. 25.6 ± 14.8 μV, respectively, at the beginning of the contraction). On the side contralateral to pain, greater estimates of ARV were identified for the upper division of trapezius as the task progressed (37.4 ± 20.2 vs. 52.7 ± 28.4 μV, at the end of the contraction). Muscle fiber conduction velocity did not change with pain in all three divisions of the right trapezius muscle. The results suggest that local elicitation of nociceptive afferents in the upper division of the trapezius induces reorganization in the coordinated activity of the three subdivisions of the trapezius in repetitive dynamic tasks.     

Identification of genes involved in the expression of atypical lipooligosaccharide structures from a second class of Haemophilus ducreyi

Haemophilus ducreyi is a gram-negative bacterium that is the causative agent of chancroid. Strain 35000HP has been well characterized and is representative of the majority of H. ducreyi strains. Strain 35000HP produces a lipooligosaccharide (LOS) that contains D-glycero-D-manno-heptose in the main oligosaccharide chain extension; the lbgB gene has been shown to encode the DD-heptosyltransferase. The lbgB gene is found in a gene cluster together with the lbgA gene, which encodes for the galactosyltransferase I. These two genes are flanked by two housekeeping genes, rpmE and xthA, encoding the ribosomal protein L31 and the exonuclease III, respectively. Recently, a second group of H. ducreyi strains have been identified. Strain 33921, a representative of the class II strains, produces an LOS that lacks DD-heptose in the oligosaccharide portion of its LOS. To better understand the biosynthesis of the DD-heptose-deficient 33921 LOS, we cloned and sequenced the corresponding lbgAB genomic region from strain 33921. Similar to strain 35000HP, the 33921 genome contains xthA and rpmE. However, between these two genes we identified genes encoding two putative glycosyltransferases that were not highly homologous to the 35000HP lbgAB genes. In this study, we demonstrate that the product of one of these genes encodes a galactosyltransferase. In addition, dot blot hybridization determined that 3 of 35 strains tested had the atypical transferases present, as did 4 strains characterized as class II strains by other criterion. These data indicate that the lbgAB genes can serve as one indicator of the classification of H. ducreyi strains.     

Occupational sensitization to lupin in the workplace: occupational asthma, rhinitis, and work-aggravated asthma

BACKGROUND: Lupin is a legume. Its seed can be ground into flour and incorporated into food as a protein source. Cases of rhinitis, urticaria, and anaphylaxis from ingestion of lupin have been reported as well as asthma. OBJECTIVE: To present a cross-sectional study of workers in a food processing company who were exposed to lupin and developed occupational allergy secondary to inhaling lupin products. METHODS: Subjects were interviewed using a standardized questionnaire, including demographics and current and past symptoms. They underwent skin prick tests (SPTs) to common aeroallergens and lupin products, spirometry, and off-line exhaled nitric oxide measurement. Symptomatic subjects, sensitized to lupin on SPT, underwent methacholine bronchial provocation challenge. Those with bronchial hyperresponsiveness had specific bronchial provocation challenge to lupin. RESULTS: A total of 53/54 subjects completed testing (98%). Overall, 21% (11/53) had positive SPT results to lupin. The lupin-sensitive group had a trend toward atopy (P = .06). Seven of 11 (64%) subjects in this group were symptomatic; all had rhinitis, and 2 had wheeze. Two subjects had positive methacholine challenges, and 1 had a positive specific bronchial provocation challenge to lupin with both an early-phase and a late-phase response. CONCLUSION: Allergy to inhaled lupin occurs in the workplace. A high sensitization rate on SPT was found, which correlated with symptoms. The clinical significance of cross-reactivity between legumes on SPT is unclear. CLINICAL IMPLICATIONS: Sensitization to the legume, lupin, can occur from exposure at work and carries a high prevalence of clinical symptoms, which in some cases leads to occupational rhinitis and asthma.     

Diagnosis of chronic endometritis in biopsies with stromal breakdown

Plasma cells are the hallmark of chronic endometritis but are not specific for upper tract infection. Plasma cells have also been noted in hormonally mediated endometrial disorders in association with gland architectural changes ("disordered proliferative" and "anovulatory" patterns), and stromal breakdown. We reviewed benign endometrial biopsies diagnosed at Beth Israel Deaconess Medical Center over a 2-year period described as disordered/anovulatory patterns +/- stromal breakdown. Cases were excluded if tissue was not available; women were younger than 50 years where most diagnoses were atrophic or cancer; or diagnoses were secretory, menstrual endometrium, or polyps. The remaining 61 cases were compared to 33 samples of unremarkable proliferative endometrium. Plasma cells were quantified on hematoxylin and eosin-stained sections and using a histochemical stain methyl green pyronin. The indication for biopsy was an abnormal pattern of bleeding in 34 cases, infertility workup in 7, incidental part of workup for pain, or other findings in 5. The majority of disordered proliferative endometrium had plasma cells (61% grade 1, 17% grade 2) all seen on methyl green pyronin staining only. Two thirds of proliferative endometrium with breakdown showed plasma cells (19% grade 1, 39% grade 2, 10 % grade 3). Plasma cells were rare in inactive endometrium and noted in only 18% of unremarkable proliferative endometrium, all grade 1. Plasma cells are commonly present in the endometrium of women with dysfunctional uterine bleeding and focal stromal breakdown. Given the lack of clinical evidence for infection, the inflammation likely represents a physiologic process.     

Longitudinal change in cognitive performance among individuals with mild cognitive impairment

The authors used mixed-effects growth models to examine longitudinal change in neuropsychological performance over a 4-year period among 197 individuals who were either normal or had mild cognitive impairment (MCI) at baseline. At follow-up, the participants were divided into 4 groups: (a) controls: participants who were normal at both baseline and follow-up (n = 33), (b) stables: participants with MCI whose Clinical Dementia Rating-Sum of Boxes (CDR-SB) score did not differ between the first and last evaluations (n = 22), (c) decliners: participants with MCI whose CDR-SB score declined between the first and last evaluations (n = 95), and (d) converters: participants who received a clinical diagnosis of Alzheimer's disease during the follow-up period (n = 47). Only the Episodic Memory factor showed a significantly greater rate of decline over the follow-up period among the converters. Two other factors were significantly lower in converters at baseline in comparison with other groups (the executive function factor and the general knowledge factor), but the rate of decline over time did not differ. Individuals with an APOE epsilon4 allele scored lower on the episodic memory and executive function factors at baseline.     

Control of differentiation in a self-renewing mammalian tissue by the histone demethylase JMJD3

The recent discovery of H3K27me3 demethylases suggests that H3K27me3 may dynamically regulate gene expression, but this potential role in mammalian tissue homeostasis remains uncharacterized. In the epidermis, a tissue that balances stem cell self-renewal with differentiation, H3K27me3, occupies the promoters of many differentiation genes. During calcium-induced differentiation, H3K27me3 was erased at these promoters in concert with loss of PcG protein occupancy and increased binding by the H3K27me3 demethylase, JMJD3. Within epidermal tissue, JMJD3 depletion blocked differentiation, while active JMJD3 dominantly induced it. These results indicate that epigenetic derepression by JMJD3 controls mammalian epidermal differentiation.     

FDA oversight of cell therapy clinical trials

The U.S. Food and Drug Administration applies regulatory flexibility to balance benefits and risks to subjects in cell-therapy clinical trials.