Although skeletal muscle weakness is documented in diabetes, the time course for its development is not established. The present study examined the dorsiflexor muscle from animals that had been diabetic for 2 wk. Adult male c57BL mice were injected once with streptozotocin (STZ) to induce diabetes (60 mg/kg ip). Two weeks later, resting membrane potential and miniature end-plate potentials were recorded, and electron microscopy was utilized for ultrastructural evaluations. After STZ-induced diabetes, both resting membrane potential and miniature end-plate potentials were reduced. Nerve terminals showed less synaptic vesicles and had degenerated mitochondria. Furthermore, in the intramuscular nerves, disorganization of microtubules and neurofilaments was evidenced. Myelin-like figures were present in intramuscular nerves, neuromuscular junctions, and muscle fibers. At the muscle level, mitochondria were swollen, with disorganization of their cristae, disruption of T tubules, and myofibers with more deposition of glycogen granules. The present results revealed early STZ-induced nerve and muscle alterations. Observed ultrastructural modifications resemble those of motoneuron disorders and aging processes. These changes are possibly related to alterations in Ca(2+) mobilization across muscle membrane. Other mechanisms such as free radical-mediated actions may also be implicated in STZ-induced effects on skeletal muscle.

No abstract

Parkinson’s disease (PD) is a severe incurable neurological disorder. It is mostly characterized by non-motor symptoms like fatigue, dementia, anxiety, speech and communication problems, depression, and so on. Electroencephalography (EEG) play a key role in the detection of the true emotional state of a person. Various studies have been proposed for the detection of emotional impairment in PD using filtering, Fourier transforms, wavelet transforms, and non-linear methods. However, these methods require a selection of basis and are confined in terms of accuracy. In this paper, tunable Q wavelet transform (TQWT) is proposed for the classification of emotions in PD and normal controls (NC). EEG signals of six emotional states namely happiness, sadness, fear, anger, surprise, and disgust are studied. Power, entropy, and statistical moments based features are elicited from the highpass and lowpass sub-bands of TQWT. Six features selected by statistical analysis are classified with a k-nearest neighbor, probabilistic neural network, random forest, decision tree, and extreme learning machine. Three performance measures are obtained, maximum mean accuracy, sensitivity, and specificity of 96.16%, 97.59%, and 88.51% for NC and 93.88%, 96.33%, and 81.67% for PD are achieved with a probabilistic neural network. The proposed method proved to be very effective such that it classifies emotions in PD and could be used as a potential tool for diagnosing emotional impairment in hospitals.

No abstract

In the Drosophila mutant dunce, short-term memory is deficient and intracellular cyclic adenosine monophosphate (cAMP) concentration is elevated. We examined the effect of increased cAMP concentration on the potassium current. The conventional whole-cell technique was applied to cultured "giant" Drosophila neurons derived from cell-division arrested embryonic neuroblasts. Potassium membrane currents were measured from: 1) control wild-type neurons, 2) wild-type neurons with dibutyryl cAMP and theophylline in the culture media for 2 days (db-cAMP-treated), and 3) dunce neurons. Delayed-rectifier potassium current was greater in both dunce neurons and db-cAMP-treated wild-type neurons than in control wild-type neurons. This result indicates that the neuronal potassium current is increased by the long-term increase of cAMP. Conceivably, altered neuronal excitability in the dunce mutant could disrupt the processing of neural signals necessary for learning and memory.