Effects of mop handle height on shoulder muscle activity and perceived exertion during floor mopping using a figure eight method

The aim of this study was to investigate effects of mop handle height on electromyographic (EMG) activities of the shoulder muscles and perceived exertion for the shoulder area during floor mopping using a figure eight method. An experimental study with 13 cleaners was conducted using surface EMG and category ratio (CR-10) scale. EMG activity was recorded unilaterally from the upper trapezius, infraspinatus, anterior and middle deltoid muscles. Each subject performed four trials of mopping and each trial consisted of using a different mop handle height (mop adjustment at the level of shoulder, chin, nose and eye) in randomized order. EMG data were normalized to a percentage of maximal voluntary contraction (%MVC). The muscle activities were assessed by estimating the 10th, 50th and 90th percentiles of the amplitude probability distribution function (APDF) of the EMG signals and analysed by linear mixed model analysis. Results showed that shoulder muscle activity was significantly lower when the mop handle height was adjusted to shoulder level or chin level as compared to eye level. These findings were supported by subjective ratings of exertion. It seems that mop handle height adjustment between shoulder and chin level may be recommended as a basis for figure eight mopping.     

Molecular genetics of the long QT syndrome: Two novel mutations of the KVLQT1 gene and phenotypic expression of the mutant gene in a large kindred

At least three different gene loci were recently shown to account for the long QT syndrome (LQTS), a monogenic disorder with altered myocardial repolarization and occurrence of life-threatening cardiac arrhythmias. We screened 44 unrelated probands for mutations of the gene encoding the cardiac potassium channel KVLQT1 using single-strand conformational polymorphism (SSCP) and subsequent DNA sequencing. Two different mutations, T182I and D188N, were identified in two separate pedigrees. Cosegregation of the mutation with the disease phenotype was evident in both families. No mutations were identified at codon 212, previously suggested to represent a mutational hot spot of the KVLQT1 channel, in any of the 44 probands. The large pedigree with the D188N mutation (30 affected and 43 nonaffected individuals) permitted an analysis of expression of the mutant gene in its documented carriers. Although the mean (± SD) Qtc interval was markedly longer in affected (484 ± 38 ms) than in nonaffected individuals (406 ± 27 ms, P < 0.001), there was a marked overlapping of individual values in these two groups. QTc values in symptomatic and asymptomatic carriers of the mutant gene were not significantly different. In conclusion, we have identified two novel mutations of the KVLQT1 component of a cardiac potassium channel. Our data support the functional significance of the pore-S6 domain of this membrane protein and emphasize the diagnostic usefulness of DNA analyses in families with LQTS. Hum Mutat 11:158–165, 1998. © 1998 Wiley-Liss, Inc.     

Acute coronary syndrome of very unusual etiology

Aortitis is one of many possible manifestations of tertiary syphilis. Aortic disease is the most common of all cardiovascular syphilitic lesions. Aortic diseases caused by tertiary syphilis include aortitis, aortic root dilation, aneurysm formation, aortic regurgitation and coronary ostial stenosis. A less common manifestation of syphilitic aortitis is coronary artery ostial narrowing related to aortic wall thickening. We report a case of a 40‐year‐old male patient admitted with a clinical picture of acute coronary syndrome (unstable angina). He had no risk factors for coronary artery disease. The physical examination revealed nothing remarkable. The admission electrocardiogram (ECG) showed ST segment depression in the anterolateral and inferior leads (Figure 1). The coronary angiogram showed critical ostial stenosis of the right (RCA) and left main coronary artery (Figure 2a, b). Cardiac‐computed tomography showed aortic wall thickening with involvement of bilateral coronary ostia (Figure 2b, c). The patient was referred for coronary bypass surgery after treatment with two doses of penicillin G. The laboratory test was strongly positive for syphilitic infection. Postoperative treatment with benzathine penicillin, in doses recommended for tertiary syphilis, was implemented.     

Recessive PYROXD1 mutations cause adult-onset limb-girdle-type muscular dystrophy

Journal of Neurology - To describe adult-onset limb-girdle-type muscular dystrophy caused by biallelic variants in the PYROXD1 gene, which has been recently linked to early-onset congenital...     

Positive modulation of δ-subunit containing GABA(A) receptors in mouse neurons

δ-subunit containing extrasynaptic GABA_A receptors are potential targets for modifying neuronal activity in a range of brain disorders. With the aim of gaining more insight in synaptic and extrasynaptic inhibition, we used a new positive modulator, AA29504, of δ-subunit containing GABA_A receptors in mouse neurons in vitro and in vivo. Whole-cell patch-clamp recordings were carried out in the dentate gyrus in mouse brain slices. In granule cells, AA29504 (1 μM) caused a 4.2-fold potentiation of a tonic current induced by THIP (1 μM), while interneurons showed a potentiation of 2.6-fold. Moreover, AA29504 (1 μM) increased the amplitude and prolonged the decay of miniature inhibitory postsynaptic currents (mIPSCs) in granule cells, and this effect was abolished by Zn²⁺ (15 μM). AA29504 (1 μM) also induced a small tonic current (12.7 ± 3.2 pA) per se, and when evaluated in a nominally GABA-free environment using Ca²⁺ imaging in cultured neurons, AA29504 showed GABA_A receptor agonism in the absence of agonist. Finally, AA29504 exerted dose-dependent stress-reducing and anxiolytic effects in mice in vivo. We propose that AA29504 potentiates δ-containing GABA_A receptors to enhance tonic inhibition, and possibly recruits perisynaptic δ-containing receptors to participate in synaptic phasic inhibition in dentate gyrus.     

The radical scavenger IAC (bis(1-hydroxy-2,2,6,6-tetramethyl-4-piperidinyl) decantionate) decreases mortality, enhances cognitive functions in water maze and reduces amyloid plaque burden in hAβPP transgenic mice

The purpose of this study was to evaluate the efficacy of the radical scavenger IAC (bis(1-hydroxy-2,2,6,6-tetramethyl-4-piperidinyl) decantionate) in alleviating behavioral deficits and reducing amyloid-β (Aβ) accumulation in an Alzheimer's disease (AD) transgenic Tg2576 mouse model. Daily treatment with IAC (3-30 mg/kg, i.p.) was started at the age of 6 months and continued until the mice were 13 months old. At the age of 9 months and again at 12 months, the mice were tested in open field and water maze tests. At the age of 13 months, the mice were sacrificed and the brains processed for immunohistochemistry. Mortality was significantly reduced in all IAC-treated groups. In addition, IAC treatment improved the water maze hidden platform training performance but had no effect on motor activity in the open field or water maze swim speed in transgenic mice. Lastly, IAC treatment (10 mg/kg) significantly reduced the cortical Aβ plaque burden. In vitro, IAC is able to increase the number of neurites and neurite branches in cultured cortical primary neurons. In conclusion, IAC slowed down the development of the AD-like phenotype in Tg2576 mice and accelerated neurite growth in cultured neurons.     

CT arthrography of the wrist using a novel, mobile, dedicated extremity cone-beam CT (CBCT)

Purpose

To evaluate the feasibility and intra- and interobserver agreement of CBCT arthrography of wrist ligaments, triangular fibrocartilaginous complex (TFCC), and to assess the sensitivity (SE), specificity (SP), accuracy (ACC), and positive and negative predictive value (PPV, NPV) of CBCT arthrography in the diagnosis of scapholunate (SLL) and lunotriquetral (LTL) ligament tears, TFCC, and cartilage abnormalities of the scaphoid and lunate with their corresponding radial surfaces (scaphoid and lunate fossa) using a novel, mobile, dedicated extremity CBCT scanner.

Materials and methods

Fifty-two consecutively enrolled subjects (26 M, 26 F, mean age 38 years, range 18–66 years) with suspected wrist ligament tears underwent CBCT-arthrography before normally scheduled MR arthrography.An extremity CBCT was used for imaging with isotropic voxel size of 0.4 × 0.4 × 0.4 mm³. Subsequent routine 1.5 T MRI was performed using a dedicated wrist coil.Two observers reviewed the anonymized CBCT images twice for contrast enhancement (CE) and technical details (TD), for tears of the SLL, LTL, and TFCC. Also, cartilage abnormalities of the scaphoid and lunate with their corresponding radial surfaces (scaphoid and lunate fossa) were evaluated. Inter- and intraobserver agreement was determined using weighted kappa statistics. Since no surgery was performed, MRI served as a reference standard, and SE and SP, ACC, PPV, and NPV were calculated.

Results

Intra- and interobserver kappa values for both readers (reader 1/reader 2; first reading/second reading) with 95 % confidence limits were: CE 0.54 (0.08–1.00)/ 0.75 (0.46–1.00); 0.73 (0.29–1.00)/ 0.45 (0.07–0.83), TD 0.53 (0.30–0.88)/ 0.86 (0.60–1.00); 0.56 (0.22–0.91)/ 0.67 (0.37–0.98), SLL 0.59 (0.25–0.93)/ 0.66 (0.42–0.91); 0.31 (0.06–0.56)/ 0.49 (0.26–0.73), LTL 0.83 (0.66–1.00)/ 0.68 (0.46–0.91); 0.90 (0.79–1.00)/ 0.48 (0.22–0.74); TFCC (0.72–1.00)/ (0.79–1.00); 0.65 (0.43–0.87)/ 0.59 (0.35–0.83), radius (scaphoid fossa) 0.45 (0.12–0.77)/ 0.64 (0.31–0.96); 0.58 (0.19–0.96)/ 0.38 (0.09–0.66), scaphoid 0.43 (0.12–0.74)/ 0.76 (0.55–0.96); 0.37 (0.00–0.75)/ 0.32 (0.04–0.59), radius (lunate fossa) 0.68 (0.36–1.00)/ 0.42 (0.00–0.86); 0.62 (0.29–0.96)/ 0.51 (0.12–0.91), and lunate 0.53 (0.16–0.90)/ 0.68 (0.44–0.91); 0.59 (0.29–0.88)/ 0.42 (0.00–0.84), respectively. The overall mean accuracy was 82–92 % and specificity was 81–94 %. Sensitivity for LTL and TFCC tears was 76–83, but for SLL tears it was 58 %. For cartilage abnormalities, the accuracy and negative predictive value were high, 90–98 %.

Conclusions

A dedicated CBCT extremity scanner is a new method for evaluating the wrist ligaments and radiocarpal cartilage. The method has an overall accuracy of 82–86 % and specificity 81–91 %. For cartilage abnormalities, the accuracy and negative predictive value were high.