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Introduction Tibial F-wave recordings are remarkable for their complexity and persistence. We postulate that the signal recorded by the E2 (reference) electrode causes this pattern. Methods Tibial F-wave recordings were made from the abductor hallucis (AH) muscle using the standard montage in 10 subjects. Additional far-field simultaneous F-wave recordings were made from the AH, the base of the large toe, and the base of the small toe with the E2 placed on the contralateral foot. Results F-wave recordings made in the standard manner and from the base of the large or small toes showed complex waveforms and similar latencies. Recordings made from the AH-contralateral foot had simple waveforms in most subjects; in 2 subjects the latencies were longer, and 1 showed reduced persistence. Conclusions The tibial F-waves are composed primarily of volume conducted recordings of the tibial-innervated foot muscles from the E2 electrode. Muscle Nerve 52: 997–1000, 2015

Purpose To describe a semi-automated program that will segment subcutaneous fat, muscle, and adipose tissue in the foot using MR imaging, determine the reliability of the program between and within raters, and determine the validity of the program using MR phantoms. Materials and Methods MR images were acquired from 19 subjects with and without diabetes and peripheral neuropathy. Two raters segmented and measured volumes from single MR slices at the forefoot, midfoot, and hindfoot at two different times. Intra- and inter-rater correlation coefficients were determined. Muscle and fat MR phantoms of known volumes were measured by the program. Results Most ICC reliability values were over 0.950. Validity estimates comparing MR estimates and known volumes resulted in r2 values above 0.970 for all phantoms. The root mean square error was less than 5% for all phantoms. Conclusion Subcutaneous fat, lean muscle, and adipose tissue volumes in the foot can be quantified in a reliable and valid way. This program can be applied in future studies investigating the relationship of these foot structures to functions in important pathologies, including the neuropathic foot or other musculoskeletal problems. J. Magn. Reson. Imaging 2013;38:1083–1093. © 2013 Wiley Periodicals, Inc.

A fungal infection has been found in the mussel Mytilus galloprovincialis from Adriatic Sea mussel farms. The infection ultimately results in the loss of the byssus, with serious consequences for mussel farming yield. The pathogen provokes the progressive destruction of the foot muscles, also damaging related structures such as the intra-organism part of the byssus apparatus, resulting in loss of the thread component. The affected health status of the animal is also sustained by modifications in the digestive gland structure, ranging from hyperactivity to extreme cell death in the tubula. At present, the identity of the harmful fungus is unknown.

The clinical manifestations of a patient with hereditary paroxysmal ataxia and neuromyotonia are described. Generalized tremor, triggered by sudden movements, and spasms of hand and foot muscles were the main clinical findings. Electromyogram (EMG) and nerve blocking studies led to the diagnosis of neuromyotonia. Treatment with acetozolamide was of no therapeutic value, confirming previous observations about the difference in response of paroxysmal ataxia with and without neuromyotonia.

Diabetic patients with neuropathy may develop motor dysfunction. In a previous study we found atrophy of the ankle extensors and flexors in neuropathic patients being more pronounced distally. This indicates that evaluation of the morphology of the foot muscles may be more sensitive for the detection of muscular atrophy in neuropathic patients. In this study we included 23 type 1 diabetic patients with a diabetes duration of 29 years (16–38) (median, range). For comparison, 23 age-, sex-, weight-, and height-matched control subjects were included. Using magnetic resonance imaging, the muscular morphology of the non-dominant foot was evaluated in all subjects. Applying stereological techniques on consecutive cross-sectional magnetic resonance images, the total volume of the foot muscles was determined. In addition, the diabetic patients were assessed clinically with a neuropathy symptom score and a neurological impairment score. Patients were also evaluated with motor nerve conduction studies and quantitative sensory examination. As compared with the healthy controls, the volume of the foot muscles was reduced in the diabetic patients being 117 cm3 (23–209) (median, range) and 166 cm3 (94-263) (p < 0.005), respectively. In the 8 non-neuropathic patients, the muscle volume was 106% (70–130) of the matched controls, whereas the 15 neuropathic patients had a muscle volume of only 49% (11–95) of the controls (p < 0.001). Furthermore, there was a close inverse relationship between the neurological impairment score and the total muscle volume (r = −0.81, p < 1*10−5). In conclusion, the volume of the foot muscles is reduced in long-term type 1 diabetic patients with neuropathy. The muscular atrophy is closely related to the severity of neuropathy. We suggest assessment of the volume of the foot muscles to be a sensitive method for the detection of motor dysfunction in diabetic neuropathy.

1. Intracellular recording from hind-limb motoneurones was used to investigate whether di- and trisynaptic (oligosynaptic) excitatory post-synaptic potentials (e.p.s.p.s) are evoked from group Ia muscle spindle afferents in those motoneurones in which such potentials are evoked from Ib tendon organ afferents or entire group I afferents. Ia afferents of triceps surae and plantaris were activated either selectively by single brief stretches of these muscles, or together with Ib afferents by electrical stimuli applied to the nerves. 2. Muscle stretches below threshold for Ib afferents (10-35 μm) evoked e.p.s.p.s which appeared with latencies compatible with disynaptic and trisynaptic coupling between the afferents and the motoneurones. The latencies of a majority of these e.p.s.p.s were too short to allow their mediation by group II afferents, if any were activated by the applied stretches. They were also too short to be compatible with effects attributable to dorsal root reflexes. These e.p.s.p.s are thus attributed to oligosynaptic actions of Ia afferents. 3. Stretch-evoked di- and trisynaptic Ia e.p.s.p.s were found in 83% of motoneurones in which e.p.s.p.s were evoked by stimuli which activated both Ia and Ib afferents; in five motoneurone species they were found in more than 90%. These observations lead to the conclusion that group Ia muscle spindle afferents evoke not only inhibitory but also excitatory actions in parallel with group Ib tendon organ afferents. 4. The distribution of Ia oligosynaptic stretch-evoked excitation from ankle and toe extensor muscles was compared with the distribution of Ia non-reciprocal inhibition as described by Jankowska, McCrea & Mackel (1981b). Excitation pre-dominated in posterior biceps—semitendinosus motoneurones and inhibition in other species of motoneurones investigated, except those of intrinsic foot muscles (tibial motoneurones); similar proportions of the latter showed excitation and inhibition. 5. Occurrence of oligosynaptic e.p.s.p.s as well as inhibitory post-synaptic potentials (i.p.s.p.s) of Ia origin in some motoneurone species, and in particular in individual motoneurones, is indicative of a number of reflex pathways between group I afferents and these motoneurones. Furthermore, the disappearance of some of the e.p.s.p.s evoked by near-threshold electrical stimulation following stronger stimuli indicates interactions between various functional groups of interneurones mediating group I actions.

1. A novel pathway is described which mediates excitation of hindlimb moto-neurones from contralateral afferents. Stimulation of contralateral limb nerves evoked short-latency (less than 5 ms) EPSPs in 55% of motoneurones tested. 2. The EPSPs were evoked by fast-conducting contralateral afferents activated by electrical stimuli of 1.04-2.5 times nerve threshold. Stimulation of contralateral muscle nerves did not evoke short-latency EPSPs, whereas nerves which contain afferents from distal skin territories (sural, superficial peroneal, tibial and saphenous nerves) did. 3. Central latencies were determined for the EPSPs from the arrival of the earliest components of the afferent volleys at the spinal cord. The earliest latencies were very brief (1.5 ms). These are comparable to the latencies of disynaptic inhibition in rat motoneurones from ipsilateral group I muscle afferents (1.5-1.7 ms). We conclude that a disynaptic relay is likely to be responsible for the earliest of the crossed EPSPs. 4. Short-latency crossed EPSPs were found in all types of motoneurone tested (including both flexor and extensor motoneurones) except in six cells innervating intrinsic foot muscles. In view of the origin and distribution of the crossed EPSPs, their possible functional role is discussed.

Summary It is claimed that the prophylactic treatment of the pedal defects so common nowadays should aim to encourage the general development of the whole musculature, to lessen the strain on the feet imposed by modern living conditions and to avoid the harmful effects of restricting footgear. A form of active therapy, based on exercises to strengthen the foot muscles which should be carried out in the pre-school years is also described. The limited value of arch supports and the most suitable footwear for pre-school children are discussed.

The myosin-linked Ca2+-regulatory system of invertebrate muscle has been described in detail only for some molluscan muscles. In this muscle-type a regulatory light chain which is readily removed by EDTA was found to serve as the regulatory component [ 1,2]. So far, only for the myosin from scallop adductor [2,3] and clam foot muscles [4] such regulatory light chains have been found, whereas in other molluscan muscles a similar system could not be demonstrated [5,6]. In contrast to these molluscan muscles the majority of invertebrate muscles are doubly regulated by a myosinand an actin-linked regulatory system [5,7]. Here the Ca2+-regulation of obliquely striated muscle was analyzed with particular attention to the mode of regulation confered by the myosin component. It is shown that, as in molluscan muscles the myosin of obliquely striated muscle posseses a regulatory light chain that is extractable with EDTA. As with molluscan musclesthe light chain may be reversibly removed and alsotifunctionally replaced by the P light chain of vertebrate smooth muscle.

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and photodensitometry of foot muscle proteins in Helix (Helix pomatia) and Achatina (Achatina fulica) demonstrate a distinctive pattern in the low molecular weight region between the two species examined. Muscle proteins from Helix showed two distinguishing bands of 18,000 and 16,000 daltons, while Achatina showed only a single band (18,000 daltons). This distinguishing feature was also evident when the foot muscles were heated at 120°C for 30 min. It is proposed that the difference in this simple pattern of low molecular weight proteins might be used as a tool to differentiate Helix meat from Achatina meat in raw, frozen, and cooked samples.