Comparative structural analysis of neuromuscular junctions in mice at different ages

The authors studied the histochemical and ultrastructural modifications that occur in the neuromuscular junctions (NMJ) of fibularis longus muscles of mice with an age range of 3 to 21 months. Twenty-four male and female animals were killed at 3, 5, 14 and 21 months of age: 7 of them at 3 months, 4 of them at 5 month, 9 at 14 months and 4 at 21 months. The fibularis longus muscles were processed and their NMJ examined with the transmission electron microscope. The most relevant changes were associated with the degeneration and retraction of terminal axons, i.e., axons poor in synaptic vesicles with degenerated mitochondria, and exhibiting multivesicular bodies and vacuoles; exposed and widened junctional folds and cytoplasmic processes of Schwann cells located in the synaptic gutter. The presence of lysosomes or lipofuchsin in the juxtajunctional sarcoplasm was also noted. These observations suggest that the phenomena of retraction and budding occur in the NMJ with advancing age, with a predominance of events associated with degeneration, leading to profound changes in NMJ shape.

Efeito de um treinamento de FNP sobre variáveis biomecânicas em idosos caidores

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Muscle Transplants for Facial Reanimation Rationale and Results of Insertion Technique Using the Palmaris Longus Tendon

Thirty-one patients with unilateral long-standing facial palsy underwent I-stage reanimation with free gracilis muscle transplant innervated by the masseteric branch of the trigeminal nerve. They were divided into 2 nonrandomized groups according to insertion technique: group 1 (9 patients), interrupted suture between the free flap and the orbicularis oris of the upper and lower lip on the paralyzed side; group It (22 patients), palmaris longus tendon graft placed between the gracilis free flap and the orbicularis oris of the upper and lower lip on the nonparalyzed side. Qualitative evaluation of the smile demonstrated better results in patients from group II. Comparing the position Of the Cupid`s bow at rest, pre- and postoperatively in each patient, we observed significant improvement of facial symmetry in both groups. During smile, however, there was a significantly higher rate of centralization of the Cupid`s bow in patients submitted to reanimation with the use of the palmaris longus tendon (group II).

A Posterior Interosseous Nerve Syndrome Associated With Spontaneous Rupture of the Extensor Pollicis Longus Tendon

Posterior interosseous nerve entrapment syndrome and spontaneous rupture of the extensor pollicis longus tendon are rare conditions. The authors describe the bizarre combination of a spontaneous rupture of the extensor pollicis longus tendon in a 82-year-old lady with a posterior interosseous nerve syndrome. As far as the authors know, this is the first description of such an association in the literature. Surgical exploration revealed compression of the posterior interosseous nerve at the proximal portion of the supinator muscle and at Henry's leash. The nerve was freed, and the tendon of the extensor index proprius was transferred to the extensor pollicis longus. Six months after the procedure, the patient had resumed her daily activities, showing a good functional result.

Salvage Flexor Hallucis Longus Transfer for a Failed Achilles Repair: Endoscopic Technique

Flexor hallucis longus (FHL) transfer is a well-established treatment option in failed Achilles tendon (AT) repair and has been routinely performed as an open procedure. We detail the surgical steps needed to perform an arthroscopic transfer of the FHL for a chronic AT rupture. The FHL tendon is harvested as it enters in its tunnel beneath the sustentaculum tali; a tunnel is then drilled in the calcaneus as near to the AT footprint as possible. By use of a suture-passing device, the free end of the FHL is advanced to the plantar aspect of the foot. After adequate tension is applied to the construct, the tendon is fixed in place with an interference screw in an inside-out fashion. This minimally invasive approach is a safe and valid alternative to classic open procedures with the obvious advantages of preserving the soft-tissue envelope and using a biologically intact tendon.

Traumatic rupture of both peroneal longus and brevis tendons.

Injuries of peroneal tendons are rare. Diagnosis of traumatic rupture is often late and presents as chronic ankle instability. A case of a complete traumatic rupture of both peroneal longus and brevis tendons with acute clinical and radiological diagnosis is presented. Surgical repair was performed by direct end-to-end suture on the 4th day after trauma, with excellent functional outcome at 1-year follow-up.

Avulsion fracture of peroneus longus tendon at the first metatarsal insertion: a case report : P16

Introduction: Isolated avulsion fracture at the plantar lateral base of the first metatarsal (M1) is very rare. Case report: A 35 year old overweight woman sustained an eversion strain of her right foot. Despite pain along M1 she was able to continue walking for three days before presenting to her family doctor. Swelling on the plantar aspect of the foot was noticed, there was also pain at eversion of the foot and extension of the ankle. Plain X-ray showed no abnormalities. A MRI showed minimal bone bruise at the basis of M1 and a partial rupture of the peroneus longus tendon at its insertion. The patient was allowed to walk with partial weight bearing with a soft ankle brace. After 6 months she presented at our hospital because of persistent pain. There was still a painful insertion of the peroneus longus but active plantarflexion of M1 was possible. Plain X-rays were poorly contributive except for a discrete flattening of the longitunal arch. CT-scan showed a non displaced fracture at the M1-basis. A protocol with partial weight-bearing in a short-leg cast and partial weight-bearing orthosis each for 6 weeks was unsuccessfully attempted. Therefore, an excision of the non healed bone fragment at the basis of M1 and a first tarsometatarsal joint arthrodesis were performed. Postoperatively the patient wore a partial weight-bearing short leg cast for 6 weeks followed by a weight-bearing short leg cast for 6 weeks with favourable outcome. Discussion: Initial internal fixation has been reported to lead to good results [1, 2]. In our case the conservative treatment failed and leaded to non union. At that time we considered as too risky (overweight) to excise the fragment and reattach the peroneus longus tendon. Therefore, we excised the fragment and fused the first tarsometatarsal joint. This procedure allowed, at least partially, to compensate for the function of the peroneus longus tendon. 1 Murakami T, et al. Avulsion fracture of the peroneus longus at the first metatarsal insertion: a case report. Br J Sports Med. 2004. 2 Kwak HY, and Bae SW. Isolated avulsion fracture at the plantar lateral base of the first metatarsal: a case report. Foot Ankle Int 2000.

Avulsion fracture of the peroneus longus tendon insertion at the base of the first metatarsal: report of a case.

Isolated avulsion fracture of the peroneus longus tendon insertion at the base of the first metatarsal is very rare. Similar to most avulsion fractures that result from excessive strain at a tendon or ligament insertion, this type of injury is caused by the strong tension exerted by the peroneus longus tendon. The mechanisms leading to this lesion and treatment options are not clearly defined. We present the case of an isolated minimally displaced intra-articular avulsion fracture at the plantar lateral base of the first metatarsal. Faced with a painful non-union following conservative treatment we considered excision of the bony fragment and first tarsometatarsal arthrodesis. This leads to a favourable functional outcome.

Translation of Longus: 'Daphnis and Chloe'

A translation into English of 'Daphnis and Chloe', the ancient Greek novel by Longus.

Ultrastructural Study of the Neuromuscular Junctions of Extensor Digitorum Longus Muscle (M. extensor digitorum longus) of the Mice

The neuromuscular junction of the extensor digitorum longus muscle of fingers was analyzed in 21 young (three months) and old (from six to 25 months) mice, from both genders. Morphologic changes were found throughout the mouse life, being more frequent and visible with aging. According with the data described in the literature consulted and the observations taken in this research, it becomes clear that a continuous process of morphological remodeling occurs in all neuromuscular ultrastructural junctions of the extensor digitorum longus muscle of fingers, during the life of the animal. Theses changes are characterized by figures of myelin in the cytoplasm of Schwann cells, pleomorphic and multivesiclar bodies, mitochondrias with morphologically altered crests in the axon terminal and degenerated junction folders. Coated vesicles are common in older animals and rare in young animals.

DISTRIBUTION OF DIFFERENT FIBER TYPES OF M-EXTENSOR CARPI RADIALIS LONGUS OF THE RAT

As revealed by the NADH-diaphorase and myosine ATPase, the M. extensor carpi radialis longus of the rat possesses at least 3 main kinds of fibres, with different distribution on the superficial and deep portions of the muscle. The superficial portion revealed that 67.68 % are FG (fast-twitch-glycolytic) fibres, 14.72 % are FOG (fast-twitch-oxidative) fibres and 17.60 % are SO (slow-twitch-glycolytic) fibres. Already the deep portion revealed that 71.29 % are SO (slow-twitch-glycolytic) fibres, 17.46 % are FOG (fast-twitch-oxidative-glycolytic) fibres and 11.25 % are FG (fast-twitch-glycolytic) fibres. The miosine ATPase reaction was used to demonstrate contracting characteristics. These findings suggest that the movements of fast contraction of the M. extensor carpi radialis longus are predominant.

Histochemical study of the extensor digitorum longus and soleus muscles in alcoholic rats

The extensor digitorum longus (EDL) and soleus (SOL) muscle fibres from albino rats submitted to experimental chronic alcoholism were evaluated in accordance with their metabolic and morphometric profiles. Twenty-seven male animals aged 4 months and weighing approximately 400 g were used. The animals were divided into three groups: control, isocaloric and alcoholic and sacrifices were carried out after 5, 10 and 15 months. The muscles were dissected, removed, cross-sectioned in a cryostat and submitted to the NADH (nicotinamide adenine dinucleotide) reaction. The SO (slow-twitch-oxidative), FG (fast-twitch-glycolytic) and FOG (fast-twitch-oxidative-glycolytic) muscle fibre types exhibited a polygonal, triangular or rounded shape and did not present noteworthy modifications in either muscles during the study. The cross-sectional areas of the fibres from the studied muscles did not present significant differences during the observations. Fibre area behaved similarly in the alcoholic animals up to the 10th month, i.e. it was decreased, as also observed in the other groups. At 15 months, however, all fibres were increased, with a predominance of FG fibres in the SOL muscle. Changes in fibre population were observed mainly in the SOL muscle of alcoholic animals: SO fibres were initially increased in number but decreased after the 10th month, and the opposite was observed for the population of FG fibres. FOG fibres increased linearly in number throughout the experiment. The statistical analysis showed nevertheless that the fibre population and cross-sectional area changes were not significant. In the alcoholic animals quantitative variations of muscle fibres were more evident in the SOL muscle, suggesting that the SOL muscle is more sensitive to the toxic action of ethanol. The results concerning the increased fibre diameter in alcoholic animals would be associated with muscle oedema induced directly or indirectly by the ethanol.

Guanidine Affects Differentially the Twitch Response of Diaphragm, Extensor Digitorum Longus and Soleus Nerve-Muscle Preparations of Mice

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