Quantitative Analysis of Surface Electromyography for Pediatric Neuromuscular Disorders.

INTRODUCTION: Needle electromyography (EMG) has been an important diagnostic tool, although discomfort may limit its use in some children. We investigated the diagnostic utility of the clustering index (CI) method, a quantitative analysis for surface EMG (SEMG), in children. METHODS: SEMG was recorded from the tibialis anterior muscle. Discriminant analysis between patients with neurogenic disorders and patients with myopathy was performed for whole epochs by using the CI and area values. RESULTS: Forty-five children (29 with myopathy, 16 with neurogenic disorders; age 9 ± 3.9 years) were enrolled. The mean discriminant function value of the neurogenic group was 0.58 ± 0.88 (-0.48-2.30), whereas that of the myopathic group was -0.55 ± 0.70 (-2.38-0.68). When the cutoff value was set at the limit of the other group, 17 of 29 children with myopathy and 7 of 16 children with neurogenic disorders were correctly classified. DISCUSSION: The CI method can be a useful noninvasive diagnostic tool in children with neuromuscular disorders. Muscle Nerve 58:824-827, 2018.

Synthesis and antimalarial activity of calothrixins A and B, and their N-alkyl derivatives.

We synthesized calothrixin B using our developed biomimetic method and derived N-alkyl-calothrixins A and B. The in vitro antimalarial activity of the calothrixin derivatives, including calothrixins A and B, against the Plasmodium falciparum FCR-3 strain was evaluated. All test compounds exhibited antimalarial activity over a concentration range of 6.4×10(-6)-1.2×10(-7) M.

Drosophila melanogaster RECQ5/QE DNA helicase: stimulation by GTP binding.

The Drosophila melanogaster RECQ5/QE gene encodes a member of the DNA helicase family comprising the Escherichia coli RecQ protein and products of the human Bloom's, Werner's, and Rothmund-Thomson syndrome genes. The full-length product of RECQ5/QE was expressed in the baculovirus system and was purified. Gel filtration experiments indicated that RECQ5/QE was present in an oligomeric state. The RECQ5/QE protein hydrolyzed ATP and even more actively GTP in the presence of single-stranded DNA. ATP drove the DNA helicase activity of RECQ5/QE, whereas GTP had little effect. GTP exhibited a stimulatory effect on DNA unwinding when it was used together with ATP. This effect was more apparent with non-hydrolyzable GTP analogs, such as GTPgammaS and GMPPNP. These results indicate that GTP binding to RECQ5/QE triggers its DNA helicase activity. GTP binding increased the rate of strand separation without affecting the S(0.5) (K(m)) values for the substrates during the DNA helicase reaction. The data collectively suggest that the RECQ5/QE protein is activated upon GTP binding through the ATP-binding site.

"Clustering Index method": a new technique for differentiation between neurogenic and myopathic changes using surface EMG.

OBJECTIVE: To establish a non-invasive and quantitative analysis method using single-channel surface EMG (SEMG) for diagnosing neurogenic and myopathic changes. METHODS: The subjects consisted of 66 healthy controls, 12 patients with neurogenic diseases, and 18 patients with myopathic diseases. The tibialis anterior muscle was examined using a belly to the adjacent bone lead. From each subject, 20-40 signals of 1 s length were collected of various strengths. A new parameter, the "Clustering Index (CI)", was developed to quantify the uneven distribution of the SEMG signal, and was plotted against the SEMG area. The results were expressed as the Z-score of each subject calculated using linear regression from the normative data. RESULTS: When ±2.5 was used as the cut-off value of the Z-score, the specificity was 95%, whereas the sensitivity was 92% (11/12) and 61% (11/18) for the neurogenic and myopathic patients, respectively. There was no overlap of the Z-score values between the neurogenic and myopathic groups. CONCLUSIONS: The CI method achieved a reasonably high diagnostic yield in detecting neurogenic or myopathic changes. SIGNIFICANCE: This is a new simple and quantitative analysis method using SEMG with good reproducibility, and is promising as a non-invasive complement to needle EMG.

Magnetic resonance imaging for diagnosis of congenital anosmia.

Magnetic Resonance Imaging (MRI) was performed on 9 patients who lacked a sense of smell since birth. Seven of them, including two patients with Kallmann syndrome, exhibited abnormality of the olfactory bulb, olfactory tract, olfactory sulcus, or rectus gyrus, with some variation among patients in type and degree of abnormality. The other two patients exhibited normal olfactory pathway morphology, and for them the possibility of acquired sensorineural anosmia could not be ruled out. MRI is useful for determining whether patients with congenital anosmia have olfactory pathway anomalies. Many patients with congenital anosmia and hypoplasty or aplasty of the olfactory pathway nevertheless had no gonadal or endocrinological disorders.