Selective Denervation Research Articles

Targeted G-protein inhibition as a novel approach to decrease vagal atrial fibrillation by selective parasympathetic attenuation

The parasympathetic nervous system is thought to play a key role in atrial fibrillation (AF). Since parasympathetic signalling is primarily mediated by the heterotrimeric G-protein, Galpha(i)betagamma, we hypothesized that targeted inhibition of Galpha(i) interactions in the posterior left atrium (PLA) would modify the substrate for vagal AF. Cell-penetrating(cp)-Galpha(i)1/2 and cp-Galpha(i)3 C-terminal peptides were assessed for their ability to attenuate cholinergic-parasympathetic signalling in isolated feline atrial myocytes and in canine left atrium (LA). Confocal fluorescence microscopy indicated that cp-Galpha(i)1/2 and/or cp-Galpha(i)3 peptides moderated carbachol attenuation of cellular Ca(2+) transients in isolated atrial myocytes. High-density epicardial mapping of dog PLA, left atrial pulmonary veins (PVs), and left atrial appendage (LAA) indicated that the delivery of cp-Galpha(i)1/2 peptide or cp-Galpha(i)3 peptide into the PLA prolonged effective refractory periods at baseline and during vagal stimulation in the PLA and to varying extents also in the LAA and PV regions. After delivery of cp-Galpha(i) peptides into the PLA, AF inducibility during vagal stimulation was significantly diminished. These results demonstrate the feasibility of using specific G(i)-protein inhibition to achieve selective parasympathetic denervation in the PLA, with a resulting change in vagal responsiveness across the entire LA.

Immunohistochemical Analysis of Laryngeal Muscles in Normal Horses and Horses With Subclinical Recurrent Laryngeal Neuropathy

We used immunohistochemistry to examine myosin heavy-chain (MyHC)-based fiber-type profiles of the right and left cricoarytenoideus dorsalis (CAD) and arytenoideus transversus (TrA) muscles of six horses without laryngoscopic evidence of recurrent laryngeal neuropathy (RLN). Results showed that CAD and TrA muscles have the same slow, 2a, and 2x fibers as equine limb muscles, but not the faster contracting fibers expressing extraocular and 2B MyHCs found in laryngeal muscles of small mammals. Muscles from three horses showed fiber-type grouping bilaterally in the TrA muscles, but only in the left CAD. Fiber-type grouping suggests that denervation and reinnervation of fibers had occurred, and that these horses had subclinical RLN. There was a virtual elimination of 2x fibers in these muscles, accompanied by a significant increase in the percentage of 2a and slow fibers, and hypertrophy of these fiber types. The results suggest that multiple pathophysiological mechanisms are at work in early RLN, including selective denervation and reinnervation of 2x muscle fibers, corruption of neural impulse traffic that regulates 2x and slow muscle fiber types, and compensatory hypertrophy of remaining fibers. We conclude that horses afflicted with mild RLN are able to remain subclinical by compensatory hypertrophy of surviving muscle fibers.

Selective Vagal Denervation of the Sinus and Atrioventricular Nodes, Guided by Vagal Reflexes Induced by High Frequency Stimulation, to Treat Refractory Neurally Mediated Syncope

A 15-year-old female patient presented with frequent episodes of vasovagal syncope refractory to non-pharmacological and pharmacological measures. Two tilt-table tests performed before and after conventional therapy were positive and reproduced the patient's clinical symptoms. Selective vagal denervation, guided by HFS, was performed. Six radiofrequency pulses were applied on the left and right sides of the interatrial septum, abolishing vagal responses at these locations. Basal sinus node and Wenckebach cycle lengths changed significantly following ablation. A tilt test performed after denervation was negative and revealed autonomic tone modification. The patient reported significant improvement in quality of life and remained asymptomatic for 9 months after denervation. After this period, three episodes of NMS occurred during a 4-month interval and a tilt test performed 11 months after the procedure demonstrated vagal activity recovery.

Thyroid hormone modulates glucose production via a sympathetic pathway from the hypothalamic paraventricular nucleus to the liver

Thyrotoxicosis increases endogenous glucose production (EGP) and induces hepatic insulin resistance. We have recently shown that these alterations can be modulated by selective hepatic sympathetic and parasympathetic denervation, pointing to neurally mediated effects of thyroid hormone on glucose metabolism. Here, we investigated the effects of central triiodothyronine (T(3)) administration on EGP. We used stable isotope dilution to measure EGP before and after i.c.v. bolus infusion of T(3) or vehicle in euthyroid rats. To study the role of hypothalamic preautonomic neurons, bilateral T(3) microdialysis in the paraventricular nucleus (PVN) was performed for 2 h. Finally, we combined T(3) microdialysis in the PVN with selective hepatic sympathetic denervation to delineate the involvement of the sympathetic nervous system in the observed metabolic alterations. T(3) microdialysis in the PVN increased EGP by 11 +/- 4% (P = 0.020), while EGP decreased by 5 +/- 8% (ns) in vehicle-treated rats (T(3) vs. Veh, P = 0.030). Plasma glucose increased by 29 +/- 5% (P = 0.0001) after T(3) microdialysis versus 8 +/- 3% in vehicle-treated rats (T(3) vs. Veh, P = 0.003). Similar effects were observed after i.c.v. T(3) administration. Effects of PVN T(3) microdialysis were independent of plasma T(3), insulin, glucagon, and corticosterone. However, selective hepatic sympathectomy completely prevented the effect of T(3) microdialysis on EGP. We conclude that stimulation of T(3)-sensitive neurons in the PVN of euthyroid rats increases EGP via sympathetic projections to the liver, independently of circulating glucoregulatory hormones. This represents a unique central pathway for modulation of hepatic glucose metabolism by thyroid hormone.

Early sympathetic denervation of splanchnic organs significantly attenuates hypertension and stroke development in stroke‐prone spontaneously hypertensive rats

Human and experimental studies have shown that splanchnic sympathetic nervous activity (SNA) is important in the development and maintenance of hypertension. The purpose of this study was to evaluate the importance of splanchnic SNA to the development of hypertension and stroke in stroke‐prone spontaneously hypertensive rats (SHRSP). To accomplish this goal, selective surgical denervation of splanchnic organs was performed by celiac ganglionectomy (CGx) in male SHRSP at 4 weeks of age (70‐80 g body weight). CGx was performed in one group of rats (n=5) while the other group underwent SHAM operation (n=4). Subsequently the rats were fed a regular diet and allowed free access to drinking water. Rats were instrumented with a radiotelemeter for blood pressure (BP) measurement at 12 weeks. After a 7 day recovery, BP was measured for 7 days. BP was significantly lower in CGx rats (138 ± 3.0 mmHg) compared to that of SHAM rats (176 ± 6.9 mmHg). All rats were then fed a Japanese style diet for 4 weeks to study whether CGx protects against stroke. BP increased in both groups but the BP difference between the groups remained. Two strokes occurred in the SHAM group while none occurred in CGx rats. We conclude that splanchnic SNA is critical in the development of hypertension and contributes to the propensity for strokes in SHRSP. (Supported by PO1‐HL070687)

Age-related changes in two- and three-dimensional morphology of type-identified endplates in the rat diaphragm

To examine the age-related morphological changes in the motor endplate of type-identified muscle fibers, 20 male Wister rats were divided into 2-month-, 10-month-, 24-month- and 30-month-old groups (n = 5 in each group). Three segments of mid-costal diaphragm muscle were removed, and then a fluorescent double-labeling technique was used to visualize the endplates on type-identified muscle fibers. Endplates were labeled with alpha-bungarotoxin-tetramethylrhodamine. Muscle segments were first incubated in antibodies to MHC isoforms (I and/or IIa) and then labeled by a second antibody with FITC. The endplates were imaged using 3D confocal microscopy with two lasers. In each age group, the planar area and volume of endplates on type-IIx/b muscle fibers were larger than those on type-I and -IIa muscle fibers, while the normalized planar areas of the endplate (endplate area/muscle fiber diameter) and the mean thickness of the endplate (volume/endplate area) were identical on all fiber types within the same age group. Decreased endplate density (endplate area/surrounding area) in the old diaphragm indicated fragmentation of the endplate, especially on type IIx/b fibers. These morphological changes may lead to functional deficiency and selective denervation of type-IIx/b muscle fiber with aging.

The Effect of Passive Movement on Denervated Soleus Highlights a Differential Nerve Control on SERCA and MyHC Isoforms

The sarco-endoplasmic reticulum Ca2+ ATP-ase (SERCA) and myosin heavy chain (MyHC) levels were measured in hindlimb-denervated and selectively denervated rat soleus muscles. Selective denervation allowed passive movement of the soleus, whereas hindlimb denervation rendered it to passivity. To minimize chronic effects, we followed the changes only for 2 weeks. Selective denervation resulted in less muscle atrophy, a faster slow-to-fast transition of MyHC isoforms, and less coordinated expressions of the slow vs fast isoforms of MyHC and SERCA. Generally, expression of the slow-twitch type SERCA2a was found to be less dependent, whereas the slow-twitch type MyHC1 was the most dependent on innervation. Our study shows that passive movement is able to ameliorate denervation-induced atrophy of the soleus and that it also accentuates the dyscoordination in the expression of the corresponding slow and fast isoforms of MyHC and SERCA.

Noradrenergic denervation facilitates the release of acetylcholine and serotonin in the hippocampus: Towards a mechanism underlying upregulations described in MCI patients?

Patients with mild cognitive impairment (MCI), who are at risk for Alzheimer's disease (AD), or those with early AD, exhibit noradrenergic degeneration in the locus coeruleus. In MCI patients, upregulations of cholinergic and serotonergic functions were described in the hippocampus. To investigate the effects of selective noradrenergic denervation on hippocampal neurotransmitter functions, rats were treated with 50mg/kg (i.p.) of N-2-chlorethyl-N-ethyl-2-bromobenzylamin (DSP-4). DSP-4 treatment reduced hippocampal noradrenaline (NA) by more than 90% (vs. controls), whereas dopamine and 5-HT levels were unaffected. The accumulation and electrically-evoked release (in nCi) of [3H]-NA in hippocampal slices were strongly reduced. Accumulation of [3H]-5-HT was reduced in DSP-4 rats, whereas spontaneous and electrically-evoked release of [3H]-5-HT was significantly enhanced, probably due to a weaker effect of endogenous NA via α2-adrenoceptors on serotonergic terminals. Accordingly, the α2-agonist UK-14,304 [5-bromo-6-(2-imidazolin-2-ylamino)-quinoxaline] more potently inhibited the evoked 5-HT release in DSP-4 rats, whereas the α2-antagonist idazoxan failed to exert facilitatory effects. Most surprisingly, the accumulation of [3H]-choline, and both the basal and electrically-evoked overflow of [3H] from hippocampal slices preincubated with [3H]-choline, were also significantly increased in DSP-4 rats. These observations suggest that noradrenergic damage in the locus coeruleus may facilitate cholinergic and serotonergic functions in the hippocampus. Although the current lesion model does not mimic the protracted evolution of neurodegenerative processes in MCI and AD, our data could point to an explanation for the upregulations of cholinergic and serotonergic functions described in the hippocampus of MCI patients.

Intracerebroventricular administration of neuropeptide Y induces hepatic insulin resistance via sympathetic innervation.

OBJECTIVE—We recently showed that intracerebroventricular infusion of neuropeptide Y (NPY) hampers inhibition of endogenous glucose production (EGP) by insulin in mice. The downstream mechanisms responsible for these effects of NPY remain to be elucidated. Therefore, the aim of this study was to establish whether intracerebroventricular NPY administration modulates the suppressive action of insulin on EGP via hepatic sympathetic or parasympathetic innervation.RESEARCH DESIGN AND METHODS—The effects of a continuous intracerebroventricular infusion of NPY on glucose turnover were determined in rats during a hyperinsulinemic-euglycemic clamp. Either rats were sham operated, or the liver was sympathetically (hepatic sympathectomy) or parasympathetically (hepatic parasympathectomy) denervated.RESULTS—Sympathectomy or parasympathectomy did not affect the capacity of insulin to suppress EGP in intracerebroventricular vehicle–infused animals (50 ± 8 vs. 49 ± 6 vs. 55 ± 6%, in hepatic sympathectomy vs. hepatic parasympathectomy vs. sham, respectively). Intracerebroventricular infusion of NPY significantly hampered the suppression of EGP by insulin in sham-denervated animals (29 ± 9 vs. 55 ± 6% for NPY/sham vs. vehicle/sham, respectively, P = 0.038). Selective sympathetic denervation of the liver completely blocked the effect of intracerebroventricular NPY administration on insulin action to suppress EGP (NPY/hepatic sympathectomy, 57 ± 7%), whereas selective parasympathetic denervation had no effect (NPY/hepatic parasympathectomy, 29 ± 7%).CONCLUSIONS—Intracerebroventricular administration of NPY acutely induces insulin resistance of EGP via activation of sympathetic output to the liver.

Selective loss of unmyelinated nerve fibers after extracorporeal shockwave application to the musculoskeletal system

Application of extracorporeal shockwaves (ESW) to the musculoskeletal system may induce long-term analgesia in the treatment of chronic tendinopathies of the shoulder, heel and elbow. However, the molecular and cellular mechanisms behind this phenomenon are largely unknown. Here we tested the hypothesis that long-term analgesia caused by ESW is due to selective loss of nerve fibers in peripheral nerves. To test this hypothesis in vivo, high-energy ESW were applied to the ventral side of the right distal femur of rabbits. After 6 weeks, the femoral and sciatic nerves were investigated at the light and electron microscopic level. Application of ESW resulted in a selective, substantial loss of unmyelinated nerve fibers within the femoral nerve of the treated hind limb, whereas the sciatic nerve of the treated hind limb remained unaffected. These data might indicate that alleviation of chronic pain by selective partial denervation may play an important role in the effects of clinical ESW application to the musculoskeletal system.

Selective denervation of the levator scapulae muscle: an amendment to the Bertrand procedure for the treatment of spasmodic torticollis

The purpose of this cadaveric study was to explore a modification to the Bertrand procedure for the treatment of spasmodic torticollis, namely the denervation of the levator scapulae (LS) muscle for laterocollis. The authors performed a series of 9 cadaveric dissections. Five were done to identify the anterior innervation of the LS, and the remaining 4 were to identify the tendinous insertions of the LS onto the lateral masses of the cervical spine via a posterior approach. The nerve supply to the LS from the anterior divisions of the C-3 and C-4 nerve roots and the contribution from the dorsal scapular nerve were identified over the anterior surface of the muscle. The C-3 and C-4 nerve root branches were situated within 2 cm of each other and inferior to the punctum nervosum. The dorsal scapular contribution was clearly identified in 2 cadavers. Selective denervation of this muscle is possible through the same posterior triangle incision used for denervating the sternocleidomastoid muscle of its accessory nerve branches. This approach will be helpful in patients with laterocollis contralateral to the direction of chin turning. The authors compare this approach to the posterior approach for sectioning the insertions of the LS muscle onto the C1-4 posterior tubercles. The latter approach is appropriate for ipsilateral laterocollis. The posterior triangle approach for denervating the LS muscle is a safe and easy addition to the Bertrand procedure and can be helpful in selected cases of torticollis with a laterocollis component.

Peroneal nerve compression by lateral gastrocnemius flap

Lateral gastrocnemius muscle flaps are reliable flaps routinely used to cover defects in the lower thigh, the knee, and the upper third of the tibia. Peroneal neuropathy following lateral gastrocnemius flap has been described previously and mostly attributed to intraoperative nerve injury. However, compression of the nerve by the flap itself has not been reported. A 56-year-old female developed right common peroneal nerve palsy 10 months after a lateral gastrocnemius flap rotation for knee prosthesis coverage. Surgical exploration found a common peroneal nerve neuroma under a compressive band formed by the lateral fascial edge of the rotated gastrocnemius muscle. The motor nerve of the flap was not denervated. When stimulated, muscle contracted and compressed the common peroneal nerve underneath. Excision of the lateral fascia and selective motor denervation were performed. Postoperatively, the patient's symptoms improved. To prevent compressive common peroneal neuropathy from lateral gastrocnemius rotational flaps, we recommend fascial excision from the lateral aspect of the muscle and selective motor denervation.

Effects of thyrotoxicosis and selective hepatic autonomic denervation on hepatic glucose metabolism in rats

Thyrotoxicosis is known to induce a broad range of changes in carbohydrate metabolism. Recent studies have identified the sympathetic and parasympathetic nervous system as major regulators of hepatic glucose metabolism. The present study aimed to investigate the pathogenesis of altered endogenous glucose production (EGP) in rats with mild thyrotoxicosis. Rats were treated with methimazole in drinking water and l-thyroxine (T(4)) from osmotic minipumps to either reinstate euthyroidism or induce thyrotoxicosis. Euthyroid and thyrotoxic rats underwent either a sham operation, a selective hepatic sympathetic denervation (Sx), or a parasympathetic denervation (Px). After 10 days of T(4) administration, all animals were submitted to a hyperinsulinemic euglycemic clamp combined with stable isotope dilution to measure EGP. Plasma triiodothyronine (T(3)) showed a fourfold increase in thyrotoxic compared with euthyroid animals. EGP was increased by 45% in thyrotoxic compared with euthyroid rats and correlated significantly with plasma T(3). In thyrotoxic rats, hepatic PEPCK mRNA expression was increased 3.5-fold. Relative suppression of EGP during hyperinsulinemia was 34% less in thyrotoxic than in euthyroid rats, indicating hepatic insulin resistance. During thyrotoxicosis, Sx attenuated the increase in EGP, whereas Px resulted in increased plasma insulin with unaltered EGP compared with intact animals, compatible with a further decrease in hepatic insulin sensitivity. We conclude that chronic, mild thyrotoxicosis in rats increases EGP, whereas it decreases hepatic insulin sensitivity. Sympathetic hepatic innervation contributes only to a limited extent to increased EGP during thyrotoxicosis, whereas parasympathetic hepatic innervation may function to restrain EGP in this condition.

Modulation of the motor response to dopaminergic drugs in a parkinsonian model of combined dopaminergic and noradrenergic degeneration

Besides dopaminergic deficiency, other neurotransmitter systems such as noradrenergic nuclei are affected in Parkinson's disease. Locus coeruleus degeneration might influence the response to dopamine replacement and the presence of long-term complications such as dyskinesias. In this scenario of noradrenergic and dopaminergic neurodegeneration, behavioural effects induced by dopaminergic-interacting drugs are incompletely known. We investigated whether noradrenergic lesion modulates the levodopa ( l-DOPA) response and modifies the response to adenosine antagonists and its interaction with l-DOPA. We examined the motor behaviour induced by: 1) subthreshold doses of l-DOPA (2mg/kg, i.p.), 2) the adenosine-receptor antagonist caffeine (10mg/kg), and 3) the combination of l-DOPA (2mg/kg) and caffeine (10mg/kg). Each study was done in two experimental conditions: a) rats with unilateral 6-OHDA lesion and b) rats with a lesion of the nigrostriatal pathway (6-OHDA) combined with selective denervation of locus coeruleus-noradrenergic terminal fields by N-(2-chloroethyl)- N-ethyl-2-bromobenzylamine (DSP-4). While only 28% of the 6-OHDA-lesioned animals presented circling behaviour after l-DOPA challenge, all (100%) double-denervated animals rotated after the same l-DOPA dose ( p < 0.05). No statistical differences in the percentage of rotating animals were observed between single- and double-denervated rats after caffeine challenge. Combined l-DOPA–caffeine challenge produced rotational behaviour in all (100%) single- and double-denervated rats. No differences in total turns were observed between single- and double-denervated animals in each treatment condition. These findings suggest that additional noradrenergic denervation selectively decreases the motor threshold to l-DOPA treatment without modifying the magnitude or the pattern of the motor response to adenosinergic antagonism.

Splanchnic Circulation Is a Critical Neural Target in Angiotensin II Salt Hypertension in Rats

Chronic angiotensin II (Ang II) infusion, in rats fed high salt, engages the sympathetic nervous system to increase venomotor tone. The splanchnic sympathetic nervous system is the most important regulator of venous tone, indicating that splanchnic sympathetic nervous system activity may be increased in Ang II salt hypertension. We hypothesized that celiac ganglionectomy (CGx), to selectively disrupt sympathetic innervation to the splanchnic circulation, would attenuate arterial pressure (AP), and venous tone increases in Ang II salt hypertension. Rats fed 2% or 0.4% NaCl were instrumented to allow AP measurement by radiotelemetry at the same time as surgical CGx or sham operation. Ang II was delivered by minipump (150 ng/kg per minute) for 14 days. CGx reduced AP independent of salt diet during control. CGx markedly attenuated Ang II hypertension in rats on 2% NaCl but had little effect in rats fed 0.4% NaCl. To test the possibility that CGx exerted its effects via renal denervation, rats were subjected to the same protocol but received selective bilateral renal denervation. Renal denervation decreased AP during control but had no protective effect on Ang II hypertension and actually tended to exacerbate the pressor response. Finally, separate groups of rats underwent CGx or sham operation and were instrumented to allow repeated measures of mean circulatory filling pressure, an index of venous tone. In addition to attenuating Ang II salt hypertension, CGx completely prevented Ang II salt-induced increases in mean circulatory filling pressure and substantially attenuated depressor responses to acute ganglion blockade. We conclude that, in the presence of high salt, Ang II activates the splanchnic sympathetic nervous system to increase venomotor tone and AP.

The Innervation of the Posterior Cricoarytenoid Muscle: Exploring Clinical Possibilities

Manipulation of the nerve supply to the posterior cricoarytenoid (PCA) muscle has potential for ameliorating the symptoms of some neurologic conditions such as abductor spasmodic dysphonia. The anatomy of the nerve supply to the PCA is better understood than in previous eras, but the anatomical understanding has not translated to clinical application yet. Microscopic dissection allowed the identification and measurement of the branches from the recurrent laryngeal nerves (RLNs) to the PCA in 43 human cadaver larynges. The cricothyroid (CT) joint was the primary landmark for measurement. Other structural measurements were also made on the larynges. All of the PCA muscles received innervation from the anterior division of the RLN. The number of direct branches from the RLN ranged from 1 to 5 (average 2.3) More than 70% of PCA muscles also received 1-3 branches off of the branch to the interarytenoid (IA) muscle. Less than half of PCA muscles received any kind of nerve branches from the posterior division of the RLN. Branches to the PCA most commonly departed the main RLN in its vertical segment and all entered the muscle from its deep surface. All branches departed the RLN within an average of 9.5mm from the CT joint; the branch to the IA occurs distal to this point. The innervation to the PCA is complex and redundant, and the segment of the RLN supplying those branches is difficult to expose safely. For these reasons, selective denervation or reinnervation procedures limited to the nerve branches may be technically difficult. When needing only to denervate the PCA, this can be accomplished by removing a portion of the PCA and the underlying nerve supply. Surgical technique should be based upon the understanding of the anatomy of the PCA muscle and its nerve supply.

Morphological Changes In Endplate On Type-identified Muscle Fiber In Aged Rat Diaphragm

PURPOSE: Previous studies demonstrated a decrease in neuromuscular activity with aging and the extent of the decrease could influence neuromuscular junction morphology and function. In this study, we compared 3-dimensional (3D) morphological properties of motor endplate on type-identified muscle fibers in diaphragm muscle between young and old rats. METHODS: Young (4 months, n=5) and old (over 2 years, n=5) male Wistar rats were used. Three segments of mid-costal diaphragm muscle were removed and then a fluorescent double-labeling technique was applied to visualize the type-identified endplate. Endplates were labeled with a-bungarotoxin conjugated tetramethylrhodamine. Myosin heavy chain (MHC) isoforms were first incubated in antibodies to MHC isoforms (I and/or IIa) and then labeled by second antibody with FITC. The endplates on type-identified muscle fibers were imaged using 3D confocal microscopy (Nikon, E600 & C1) with 2 lasers (543nm for rhodamine and 488nm for FITC) and software (solution systems, 3D doctor). RESULTS: In young diaphragm, the planar area and volume of endplate on type-I and -IIa muscle fiber were smaller than those on type-IIb/x fiber, while the normalized planar areas of endplate to muscle fiber diameter were identical on all fiber types. The receptor densities (endplate area/outer surrounding area) on all fiber types were identical (70, 67 and 68 % on type I, IIa and IIb/x fibers). With aging, the planar area and volume of endplate increased on all fiber type, and there were no significant changes in the normalized endplate area to fiber diameter. However, the receptor densities on endplates of all fiber types were significantly lower in specimens from old rats (63, 56 and 45 % on type I, IIa and IIb/x fibers) compared to those in young diaphragm. Furthermore, the density on type IIb/x fiber was significant lower than those on type I and IIa fibers in old diaphragm. CONCLUSIONS: The identical values of normalized endplate area to fiber diameter between young and old diaphragm suggest the compensatory expansion of endplate with aging. Decreased receptor density in the old diaphragm indicates fragmentation of the endplate. These morphological changes might lead to functional deficiency and selective denervation on type-IIb/x muscle fiber with aging.

Abordagem cirúrgica inédita para denervação acetabular em cães

Este artigo tem por objetivo demonstrar nova abordagem cirúrgica para denervação seletiva das fibras sensitivas do periósteo acetabular, para tratamento da displasia coxo femoral em cães, conduzidas em 189 articulações. Para tanto, é descrita abordagem da região cranial e dorso-lateral do acetábulo de cães por incisão em forma de meia lua de aproximadamente de três centímetros de extensão, iniciando trocânter maior do fêmur e em direção ao corpo do ílio. Após rebatimento dorsal do músculo glúteo médio, secciona-se parcialmente a inserção do m. glúteo profundo para acesso às regiões citadas. Com auxílio de cureta foi removido, em todos os pacientes, periósteo na margem acetabular cranial e dorso lateral, até a exposição da cortical óssea. Em todos os animais foi possível a abordagem, tanto da face cranial como também acesso para a curetagem da face dorsal do acetábulo, com a técnica descrita, com incisão de pele de aproximadamente 3,2cm. A curetagem da porção cranial do acetábulo foi, em todos os casos realizados, sem visualização do osso, mas de fácil confecção e sem intercorrências de lesão de nervos ou músculos. Em todas as abordagens foi possível visualizar a cápsula articular da articulação coxo femoral, e em nenhum dos animais esta estrutura foi incisada por erro de técnica. Conclui-se que a abordagem cirúrgica descrita no presente trabalho é factível para este tipo de procedimento cirúrgico em cães, promovendo acesso adequado, com mínima invasão e sem complicações de qualquer natureza.

The management of cervical dystonia

Cervical dystonia (CD), also known as ‘spasmodic torticollis’, is the most common form of adult-onset focal dystonia. It is a chronic disorder for which there is no curative treatment. Proposed interventions only have a symptomatic effect that is directed at controlling the intensity of the dystonic contractions and their associated symptoms. Both serotypes of botulinum toxin (BtA and BtB) have shown efficacy for the treatment of CD, and they constitute the first-line therapy for CD. BtB constitutes the best medical treatment for secondary failures to BtA. The efficacy of all other proposed medications, including anticholinergics, should be considered unknown due to the lack of good-quality trials. This lack of evidence applies also to all physical rehabilitation treatments. Although the authors have concluded that all surgical procedures for CD should still be considered investigational, the best data supporting benefit of surgery comes from case series of selective peripheral denervation and pallidal deep brain stimulation.

Care Seeking and Treatment for Urinary Incontinence in a Diverse Population

We examined care seeking and treatment for urine leakage in the Boston Area Community Health Survey, a racially and ethnically diverse, community based study of urological and gynecological symptoms and their correlates. Boston Area Community Health Survey used a multistage, stratified cluster design to enroll 5,506 black, Hispanic and white adults. Subjects were 30 to 79 years old and residents of Boston, Massachusetts. Data were obtained during a 2-hour in home interview. Analyses for this report include the 331 women and 128 men who reported weekly incontinence, defined as urine leakage that occurred 1 or more times weekly in the last year. Of women 45% and 22% of men with weekly incontinence reported ever having sought care for it. Of those who sought care 60% reported receiving treatment and half of those who were treated continued to have daily leakage. Of treated women 50% and 40% of treated men reported moderate to great frustration with continued urine leakage. This study demonstrates that the majority of men and women who experience weekly urinary incontinence do not seek care for it, many who sought treatment believe that none was provided and many who received treatment continue to have troubling symptoms. The public should be educated to seek care for urine leakage, health care providers should take the initiative to ask their patients about urinary symptoms and more attention should be given to ensuring that, when treatment is given, it is appropriate and effective.