Randomized controlled pilot trial of prazosin for prophylaxis of posttraumatic headaches in active-duty service members and veterans

OBJECTIVE

Evaluate the efficacy and tolerability of prazosin for prophylaxis of headaches following mild traumatic brain injury in active-duty service members and military veterans.

BACKGROUND

Prazosin is an alpha-1 adrenoreceptor antagonist that reduces noradrenergic signaling. An open-label trial in which prazosin reduced headache frequency in veterans following mild traumatic brain injury provided the rationale for this pilot study.

METHODS

A 22-week parallel-group randomized controlled trial  which included 48 military veterans and active-duty service members with mild traumatic brain injury-related headaches was performed. The study design was based on International Headache Society consensus guidelines for randomized controlled trials for chronic migraine. Following a pre-treatment baseline phase, participants with at least eight qualifying headache days per 4 weeks were randomized 2:1 to prazosin or placebo. After a 5-week titration to a maximum possible dose of 5 mg (morning) and 20 mg (evening), participants were maintained on the achieved dose for 12 weeks. Outcome measures were evaluated in 4-week blocks during the maintenance dose phase. The primary outcome measure was change in 4-week frequency of qualifying headache days. Secondary outcome measures were percent participants achieving at least 50% reduction in qualifying headache days and change in Headache Impact Test-6 scores.

RESULTS

Intent-to-treat analysis of randomized study participants (prazosin N = 32; placebo N = 16) demonstrated greater benefit over time in the prazosin group for all three outcome measures. In prazosin versus placebo participants, reductions from baseline to the final rating period for 4-week headache frequency were -11.9 ± 1.0 (mean ± standard error) versus -6.7 ± 1.5, a prazosin minus placebo difference of -5.2 (-8.8, -1.6 [95% confidence interval]), p = 0.005 and for Headache Impact Test-6 scores were -6.0 ± 1.3 versus +0.6 ± 1.8, a difference of -6.6 (-11.0, -2.2), p = 0.004. The mean predicted percent of participants at 12 weeks with ≥50% reduction in headache days/4 weeks, baseline to final rating, was 70 ± 8% for prazosin (21/30) versus 29 ± 12% for placebo (4/14), odds ratio 5.8 (1.44, 23.6), p = 0.013. The trial completion rate of 94% in the prazosin group (30/32) and 88% in the placebo group (14/16) indicated that prazosin was generally well tolerated at the administered dose regimen. Morning drowsiness/lethargy was the only adverse effect that differed significantly between groups, affecting 69% of the prazosin group (22/32) versus 19% of the placebo group (3/16), p = 0.002.

CONCLUSIONS

This pilot study provides a clinically meaningful efficacy signal for prazosin prophylaxis of posttraumatic headaches. A larger randomized controlled trial is needed to confirm and extend these promising results.

Nature and Action of Antibodies in Myasthenia Gravis

This article discusses antibodies associated with immune-mediated myasthenia gravis and the pathologic action of these antibodies at the neuromuscular junctions of skeletal muscle. To explain how these antibodies act, we consider the physiology of neuromuscular transmission with emphasis on 4 features: the structure of the neuromuscular junction; the roles of postsynaptic acetylcholine receptors and voltage-gated Na⁺ channels and in converting the chemical signal from the nerve terminal into a propagated action potential on the muscle fiber that triggers muscle contraction; the safety factor for neuromuscular transmission; and how the safety factor is reduced in different forms of autoimmune myasthenia gravis.

Independent home use of a brain-computer interface by people with amyotrophic lateral sclerosis

OBJECTIVE

To assess the reliability and usefulness of an EEG-based brain-computer interface (BCI) for patients with advanced amyotrophic lateral sclerosis (ALS) who used it independently at home for up to 18 months.

METHODS

Of 42 patients consented, 39 (93%) met the study criteria, and 37 (88%) were assessed for use of the Wadsworth BCI. Nine (21%) could not use the BCI. Of the other 28, 27 (men, age 28-79 years) (64%) had the BCI placed in their homes, and they and their caregivers were trained to use it. Use data were collected by Internet. Periodic visits evaluated BCI benefit and burden and quality of life.

RESULTS

Over subsequent months, 12 (29% of the original 42) left the study because of death or rapid disease progression and 6 (14%) left because of decreased interest. Fourteen (33%) completed training and used the BCI independently, mainly for communication. Technical problems were rare. Patient and caregiver ratings indicated that BCI benefit exceeded burden. Quality of life remained stable. Of those not lost to the disease, half completed the study; all but 1 patient kept the BCI for further use.

CONCLUSION

The Wadsworth BCI home system can function reliably and usefully when operated by patients in their homes. BCIs that support communication are at present most suitable for people who are severely disabled but are otherwise in stable health. Improvements in BCI convenience and performance, including some now underway, should increase the number of people who find them useful and the extent to which they are used.

Pathophysiological links between traumatic brain injury and post-traumatic headaches

This article reviews possible ways that traumatic brain injury (TBI) can induce migraine-type post-traumatic headaches (PTHs) in children, adults, civilians, and military personnel. Several cerebral alterations resulting from TBI can foster the development of PTH, including neuroinflammation that can activate neural systems associated with migraine. TBI can also compromise the intrinsic pain modulation system and this would increase the level of perceived pain associated with PTH. Depression and anxiety disorders, especially post-traumatic stress disorder (PTSD), are associated with TBI and these psychological conditions can directly intensify PTH. Additionally, depression and PTSD alter sleep and this will increase headache severity and foster the genesis of PTH. This article also reviews the anatomic loci of injury associated with TBI and notes the overlap between areas of injury associated with TBI and PTSD.

Post-traumatic headaches in civilians and military personnel: a comparative, clinical review

Post-traumatic headache (PTH) is the most frequent symptom after traumatic brain injury (TBI). We review the epidemiology and characterization of PTH in military and civilian settings. PTH appears to be more likely to develop following mild TBI (concussion) compared with moderate or severe TBI. PTH often clinically resembles primary headache disorders, usually migraine. For migraine-like PTH, individuals who had the most severe headache pain had the highest headache frequencies. Based on studies to date in both civilian and military settings, we recommend changes to the current definition of PTH. Anxiety disorders such as post-traumatic stress disorder (PTSD) are frequently associated with TBI, especially in military populations and in combat settings. PTSD can complicate treatment of PTH as a comorbid condition of post-concussion syndrome. PTH should not be treated as an isolated condition. Comorbid conditions such as PTSD and sleep disturbances also need to be treated. Double-blind placebo-controlled trials in PTH population are necessary to see whether similar phenotypes in the primary headache disorders and PTH will respond similarly to treatment. Until blinded treatment trials are completed, we suggest that, when possible, PTH be treated as one would treat the primary headache disorder(s) that the PTH most closely resembles.

Formation and Function of Acute Stroke–Ready Hospitals Within a Stroke System of Care Recommendations From the Brain Attack Coalition

Background and Purpose—

Many patients with an acute stroke live in areas without ready access to a Primary or Comprehensive Stroke Center. The formation of care facilities that meet the needs of these patients might improve their care and outcomes and guide them and emergency responders to such centers within a stroke system of care.

Methods—

The Brain Attack Coalition conducted an electronic search of the English medical literature from January 2000 to December 2012 to identify care elements and processes shown to be beneficial for acute stroke care. We used evidence grading and consensus paradigms to synthesize recommendations for Acute Stroke–Ready Hospitals (ASRHs).

Results—

Several key elements for an ASRH were identified, including acute stroke teams, written care protocols, involvement of emergency medical services and emergency department, and rapid laboratory and neuroimaging testing. Unique aspects include the use of telemedicine, hospital transfer protocols, and drip and ship therapies. Emergent therapies include the use of intravenous tissue-type plasminogen activator and the reversal of coagulopathies. Although many of the care elements are similar to those of a Primary Stroke Center, compliance rates of ≥67% are suggested in recognition of the staffing, logistical, and financial challenges faced by rural facilities.

Conclusions—

ASRHs will form the foundation for acute stroke care in many settings. Recommended elements of an ASRH build on those proven to improve care and outcomes at Primary Stroke Centers. The ASRH will be a key component for patient care within an evolving stroke system of care.

For veterans with mild traumatic brain injury, improved posttraumatic stress disorder severity and sleep correlated with symptomatic improvement

This was an observational study of a cohort of 63 Operation Iraqi Freedom/Operation Enduring Freedom veterans with mild traumatic brain injury (mTBI) associated with an explosion. They had headaches, residual neurological deficits (NDs) on neurological examination, and posttraumatic stress disorder (PTSD) and were seen on average 2.5 years after their last mTBI. We treated them with sleep hygiene counseling and oral prazosin. We monitored headache severity, daytime sleepiness using the Epworth Sleepiness Scale, cognitive performance using the Montreal Cognitive Assessment test, and the presence of NDs. We quantitatively measured olfaction and assessed PTSD severity using the PTSD Checklist-Military Version. Nine weeks after starting sleep counseling and bedtime prazosin, the veterans' headache severity decreased, cognitive function as assayed with a brief screening tool improved, and daytime sleepiness diminished. Six months after completing treatment, the veterans demonstrated additional improvement in headache severity and daytime sleepiness and their improvements in cognitive function persisted. There were no changes in the prevalence of NDs or olfaction scores. Clinical improvements correlated with reduced PTSD severity and daytime sleepiness. The data suggested that reduced clinical manifestations following mTBI correlated with PTSD severity and improvement in sleep, but not the presence of NDs or olfaction impairment.

Neuromuscular transmission failure in myasthenia gravis: decrement of safety factor and susceptibility of extraocular muscles

An appropriate density of acetylcholine receptors (AChRs) and Na(+) channels (NaChs) in the normal neuromuscular junction (NMJ) determines the magnitude of safety factor (SF) that guarantees fidelity of neuromuscular transmission. In myasthenia gravis (MG), an overall simplification of the postsynaptic folding secondary to NMJ destruction results in AChRs and NaChs depletion. Loss of AChRs and NaChs accounts, respectively, for 59% and 40% reduction of the SF at the endplate, which manifests as neuromuscular transmission failure. The extraocular muscles (EOM) have physiologically less developed postsynaptic folding, hence a lower baseline SF, which predisposes them to dysfunction in MG and development of fatigue during "high performance" eye movements, such as saccades. However, saccades in MG show stereotyped, conjugate initial components, similar to normal, which might reflect preserved neuromuscular transmission fidelity at the NMJ of the fast, pale global fibers, which have better developed postsynaptic folding than other extraocular fibers.

Military- and sports-related mild traumatic brain injury: clinical presentation, management, and long-term consequences

CME Background

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Participants may receive credit by reading the article, correctly answering at least 70% of the questions in the Posttest, and completing the Evaluation. The Posttest and Evaluation are now available online only at PSYCHIATRIST.COM (Keyword: February).

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After studying the Commentary by Peskind et al, you should be able to:

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The CME Institute of Physicians Postgraduate Press, Inc., designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 Credit ™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Note

The American Academy of Physician Assistants (AAPA) accepts certificates of participation for educational activities certified for AMA PRA Category 1 Credit ™ from organizations accredited by ACCME or a recognized state medical society. Physician assistants may receive a maximum of 1 hour of Category I credit for completing this program.

Date of Original Release/Review

This educational activity is eligible for AMA PRA Category 1 Credit ™ through February 29, 2016. The latest review of this material was January 2013.

Recovery of coordinated gait: randomized controlled stroke trial of functional electrical stimulation (FES) versus no FES, with weight-supported treadmill and over-ground training

BACKGROUND

No single intervention restores the coordinated components of gait after stroke.

OBJECTIVE

The authors tested the multimodal Gait Training Protocol, with or without functional electrical stimulation (FES), to improve volitional walking (without FES) in patients with persistent (>6 months) dyscoordinated gait.

METHODS

A total of 53 subjects were stratified and randomly allocated to either FES with intramuscular (IM) electrodes (FES-IM) or No-FES. Both groups received 1.5-hour training sessions 4 times a week for 12 weeks of coordination exercises, body weight-supported treadmill training (BWSTT), and over-ground walking, provided with FES-IM or No-FES. The primary outcome was the Gait Assessment and Intervention Tool (G.A.I.T.) of coordinated movement components, with secondary measures, including manual muscle testing, isolated leg movements (Fugl-Meyer scale), 6-Minute Walk Test, and Locomotion/Mobility subscale of the Functional Independence Measure (FIM).

RESULTS

No baseline differences in subject characteristics and measures were found. The G.A.I.T. showed an additive advantage with FES-IM versus No-FES (parameter statistic 1.10; P = .045, 95% CI = 0.023-2.179) at the end of training. For both FES-IM and No-FES, a within-group, pre/posttreatment gain was present for all measures (P < .05), and a continued benefit from mid- to posttreatment (P < .05) was present. For FES-IM, recovered coordinated gait persisted at 6-month follow-up but not for No-FES.

CONCLUSION

Improved gait coordination and function were produced by the multimodal Gait Training Protocol. FES-IM added significant gains that were maintained for 6 months after the completion of training.

Rehabilitation in the patient with mild traumatic brain injury

Traumatic brain injury (TBI) has garnered increased public attention in the past several years because of high-profile athletes with possible long-term effects of their injuries as well as large numbers of returning combat veterans injured by blast explosions. Most of these injuries are mild in nature and require no specific surgical treatment but may benefit from brief rehabilitation interventions. To appropriately rehabilitate patients with mild traumatic brain injury (mTBI), one must fully understand its clinical course and the factors that accelerate or delay recovery. Education is the centerpiece of mTBI treatment and should be included in the rehabilitation plan. When devising the rehabilitation plan, the neurologist should take into account the goals of the patient and establish a reasonable time frame for treatment paralleling the expected recovery course. Cognitive and vestibular functions are commonly affected after mTBI and are particularly responsive to rehabilitation interventions. Vocational rehabilitation and community reentry planning are aspects of the global rehabilitation plan that should not be neglected. Combat-injured veterans with mTBI present unique challenges to the rehabilitation team, and assessment of these patients often needs to include assessment of psychological function.

INa and IKir are reduced in Type 1 hypokalemic and thyrotoxic periodic paralysis

We evaluated voltage-gated Na(+) (I(Na)) and inward rectifier K(+) (I(Kir)) currents and Na(+) conductance (G(Na)) in patients with Type 1 hypokalemic (HOPP) and thyrotoxic periodic paralysis (TPP). We studied intercostal muscle fibers from five subjects with HOPP and one with TPP. TPP was studied when the patient was thyrotoxic (T-toxic) and euthyroid. We measured: (1) I(Kir), (2) action potential thresholds, (3) I(Na), (4) G(Na), (5) intracellular [Ca(2+)], and (6) histochemical fiber type. HOPP fibers had lower I(Na), G(Na), and I(Kir) and increased action potential thresholds. Paralytic attack frequency correlated with the action potential threshold, G(Na) and I(Na), but not with I(Kir). G(Na), I(Na), and [Ca(2+)] varied with fiber type. HOPP fibers had increased [Ca(2+)]. The subject with TPP had values for G(Na), I(Na), action potential threshold, I(Kir), and [Ca(2+)] that were similar to HOPP when T-toxic and to controls when euthyroid. HOPP T-toxic TPP fibers had altered G(Na), I(Na), and I(Kir) associated with elevation in [Ca(2+)].

Relationships between mild traumatic brain injury sustained in combat and post-traumatic stress disorder

The setting of the trauma is a distinguishing feature between mild traumatic brain injury (mTBI; also called concussion) that occurs in civilian settings compared with that occurring in combat. Combat mTBI is frequently associated with a prolonged stress reaction, post-traumatic stress disorder (PTSD). Individuals with mTBI and PTSD from combat in Operations Iraqi Freedom and Enduring Freedom often develop prolonged post-concussion symptoms (PCSs) such as headache. Both mTBI and PTSD may contribute to PCSs. PTSD may worsen and prolong the PCSs following mTBI by disrupting sleep. It is not known how mTBI predisposes an individual to develop PTSD.

Response of sagittal plane gait kinematics to weight-supported treadmill training and functional neuromuscular stimulation following stroke

After stroke, persistent gait deficits cause debilitating falls and poor functional mobility. Gait restoration can preclude these outcomes. Sixteen subjects (>12 months poststroke) were randomized to two gait training groups. Group 1 received 12 weeks of treatment, 4 times a week, 90 min per session, including 30 min strengthening and coordination, 30 min over-ground gait training, and 30 min weight-supported treadmill training. Group 2 received the same treatment, but also used functional neuromuscular stimulation (FNS) with intramuscular (IM) electrodes (FNS-IM) for each aspect of treatment. Outcome measures were kinematics of gait swing phase. Both groups showed no significant pre-/posttreatment gains in peak swing hip flexion. Group 1 (no FNS) had no significant gains in other gait components at posttreatment or at follow-up. Group 2 (FNS-IM) had significant gains in peak swing knee flexion and mid-swing ankle dorsiflexion (p < 0.05) that were maintained for 6 months.

Physiological Cost Index as a proxy measure for the oxygen cost of gait in stroke patients

BACKGROUND

Stroke survivors can exhibit abnormally elevated oxygen consumption during walking. Therapeutic interventions can improve gait deficits and oxygen consumption. A practical measure of oxygen cost is not available. This study tested the usefulness of an indirect index of oxygen cost, the Physiological Cost Index, and the ability of this index to discriminate between healthy adults and stroke survivors.

METHODS

The authors studied 17 subjects with stroke and 10 healthy control participants. Participants walked 10 minutes at their chosen comfortable speed on a treadmill. Oxygen consumption and heart rate data were collected. Primary measures were oxygen cost and the Physiological Cost Index. Secondary measures were age and gait speed.

RESULTS

The Physiological Cost Index and oxygen cost had a good to excellent correlation (r = .83, P < .001) for subjects with stroke. Both oxygen cost and the Physiological Cost Index were comparable in detecting a significantly abnormal elevation for stroke survivors versus healthy adults (P = .003 and .002, respectively). Age was not correlated with oxygen cost, the Physiological Cost Index, or chosen gait speed. A moderate correlation of gait speed to both the Physiological Cost Index and oxygen cost was found.

CONCLUSIONS

The Physiological Cost Index can be used as a proxy index for the oxygen cost of walking in subjects after stroke because it is correlated with oxygen cost and is comparable to oxygen cost in its capability to discriminate between healthy controls and subjects with stroke. The Physiological Cost Index can be performed inexpensively on a routine basis in a clinical environment.

Directed rehabilitation reduces pain and depression while increasing independence and satisfaction with life for patients with paraplegia due to epidural metastatic spinal cord compression

We determined whether directed rehabilitation affected survival, pain, depression, independence, and satisfaction with life for veterans who were nonambulatory after spinal epidural metastasis (SEM) treatment. We compared 12 consecutive paraplegic veterans who received 2 weeks of directed rehabilitation with a historical control group of 30 paraplegic veterans who did not receive rehabilitation. The rehabilitation program emphasized transfers, bowel and bladder care, incentive spirometry, nutrition, and skin care. The outcome measures were survival, independence, pain levels, depression, and satisfaction with life. Patients receiving rehabilitation had longer median survivals, fewer deaths from myelopathic complications, less pain 2 weeks after SEM treatment, lower depression scores, and higher satisfaction with life scores. In addition, among the patients who received rehabilitation, eight became independent for transfers (vs zero controls) and nine returned home (vs six controls). We conclude that directed rehabilitation reduced patients' pain levels and increased their mobility, survival, and life satisfaction.

Persistent benefits of rehabilitation on pain and life quality for nonambulatory patients with spinal epidural metastasis

We determined whether the benefits of directed rehabilitation for pain, depression, and satisfaction with life persisted for veterans who were nonambulatory after spinal epidural metastasis (SEM) treatment. Twelve consecutive veterans (paraplegic after SEM treatment) who received 2 weeks of directed rehabilitation were compared with a historical control group of thirty paraplegic veterans who did not receive rehabilitation. Subjects were followed until death. Pain levels, depression, satisfaction with life, and consumption of pain medication were measured. Subjects who received rehabilitation had less pain, consumed less pain medication, were less depressed, and had higher satisfaction with life. The benefits to the rehabilitated subjects persisted until their deaths. We conclude that spinal cord injury rehabilitation for nonambulatory subjects with SEM produces persistent benefits for pain, depression, and satisfaction with life.

A randomized controlled trial of functional neuromuscular stimulation in chronic stroke subjects

BACKGROUND AND PURPOSE

Conventional therapies fail to restore normal gait to many patients after stroke. The study purpose was to test response to coordination exercise, overground gait training, and weight-supported treadmill training, both with and without functional neuromuscular stimulation (FNS) using intramuscular (IM) electrodes (FNS-IM).

METHODS

In a randomized controlled trial, 32 subjects (>1 year after stroke) were assigned to 1 of 2 groups: FNS-IM or No-FNS. Inclusion criteria included ability to walk independently but inability to execute a normal swing or stance phase. All subjects were treated 4 times per week for 12 weeks. The primary outcome measure, obtained by a blinded evaluator, was gait component execution, according to the Tinetti gait scale. Secondary measures were coordination, balance, and 6-minute walking distance.

RESULTS

Before treatment, there were no significant differences between the 2 groups for age, time since stroke, stroke severity, and each study measure. FNS-IM produced a statistically significant greater gain versus No-FNS for gait component execution (P=0.003; parameter estimate 2.9; 95% CI, 1.2 to 4.6) and knee flexion coordination (P=0.049).

CONCLUSIONS

FNS-IM can have a significant advantage versus No-FNS in improving gait components and knee flexion coordination after stroke.

Response to upper-limb robotics and functional neuromuscular

Twelve moderately to severely involved chronic stroke survivors (>12 mo) were randomized to one of two treatments: robotics and motor learning (ROB-ML) or functional neuromuscular stimulation and motor learning (FNS-ML). Treatment was 5 h/d, 5 d/wk for 12 wk. ROB-ML group had 1.5 h per session devoted to robotics shoulder and elbow (S/E) training. FNS-ML had 1.5 h per session devoted to functional neuromuscular stimulation (surface electrodes) for wrist and hand (W/H) flexors/extensors. The primary outcome measure was the functional measure Arm Motor Ability Test (AMAT). Secondary measures were AMAT-S/E and AMAT-W/H, Fugl-Meyer (FM) upper-limb coordination, and the motor control measures of target accuracy (TA) and smoothness of movement (SM). ROB-ML produced significant gains in AMAT, AMAT-S/E, FM upper-limb coordination, TA, and SM. FNS-ML produced significant gains in AMAT-W/H and FM upper-limb coordination.

Feasibility of combining multi-channel functional neuromuscular stimulation with weight-supported treadmill training

More than 3 million stroke survivors live with residual disabilities and mobility deficits even after rehabilitation. Therefore, it is important to develop new, more effective, gait training methods. The purpose of this study was twofold: (1) testing the feasibility of combining multi-channel functional neuromuscular stimulation (FNS) using intramuscular (IM) electrodes and body weight supported treadmill training (BWSTT) for gait training; and (2) documenting the potential gait practice advantages afforded by combining FNS-IM and BWSTT. Eight subjects with gait deficits in the chronic phase (>12 months) were enrolled. Intramuscular electrodes were placed in the paretic hip abductors, knee flexors and extensors, and ankle dorsiflexors, plantarflexors, and evertors. Subjects were treated with exercise and gait training using the combined technologies 1 1/2 h/week, four times/week, for 12 weeks. Feasibility was tested according to performance of the technologies, clinician skill factors, and subject satisfaction. Impairment, function, and quality of life were measured. Provision of practice for eight gait characteristics was catalogued. We found the following results for the combined technologies: (1) the combined technologies were safe and feasible; (2) clinicians required five training sessions to reach proficiency; (3) subjects were satisfied; (4) there were significant gains in impairment and functional measures; (5) a greater number of gait practice characteristics were provided with the combined technologies than with either alone.

Neurophysiology of the neuromuscular junction: overview

This manuscript reviews the physiology of neuromuscular transmission with emphasis on four features: (1) the structure of the neuromuscular junction, (2) release of vesicles of acetylcholine from the nerve terminal, (3) the roles of postsynaptic Na(+) channels and acetylcholine receptors in converting the chemical signal from the nerve terminal into a propagated action potential on the muscle fiber, and (4) the safety factor for neuromuscular transmission. It also introduces new information about how the neuromuscular junction maintains physiological integrity during muscle fiber stretch and contraction.

Susceptibility of Ocular Tissues to Autoimmune Diseases

The orbital tissues may form a unique immunological environment, as evidenced by autoimmune disorders that specifically target orbital tissues, particularly myasthenia gravis (MG) and Graves' ophthalmopathy (GO). The reasons for the preferential susceptibility are likely to be multiple, based on the interplay of molecular and physiological properties of extraocular muscles (EOM), the unique requirements of the ocular motor system, and the specific autoimmune pathology. Of general importance, even a minor loss of EOM force generation will sufficiently misalign the visual axes to produce dramatic symptoms, and proprioceptive feedback is limited to overcome such a deficit. Particular to MG, EOM synapses appear susceptible to neuromuscular blockade, the autoimmune pathology differs between ocular and generalized MG patients, and the influence of complement regulatory factors may be less prominent in preventing damage at EOM neuromuscular junctions. GO pathogenesis is poorly understood, but shared epitopes of orbital fibroblasts, EOM, and thyroid could lead to specific autoimmune targeting of these tissues. The differential response of orbital fibroblasts to cytokines may be a key factor in disease development. Greater appreciation of the immunologic environment of orbital tissues may lead to therapies specifically designed for orbital autoimmune diseases.

Changes in contractile properties of skeletal muscle during developmentally programmed atrophy and death

Skeletal muscle atrophy and death are protracted processes that accompany aging and pathological insults in mammals. The intersegmental muscles (ISMs) from the tobacco hawkmoth Manduca sexta are composed of giant fibers that undergo distinct hormonally-regulated programs of atrophy and death at the end of metamorphosis. Atrophy occurs during the 3 days preceding adult emergence and results in a 40% reduction of mass, whereas death takes place during the subsequent 30 h and results in the complete loss of the fibers. There are no significant changes in tetanic force or calcium sensitivity in skinned fiber preparations during atrophy. However, the size of caffeine-induced contractions fell by about 50%. With the onset of the death phase, dramatic reductions occur in ISM: tetanic force, twitch amplitude, resting potential, caffeine-induced contractions, calcium sensitivity, and Hill coefficients. Several lines of evidence suggest that ISM atrophy is caused by an increase in protein turnover without significant modification of fiber organization. In contrast, ISM death is accompanied by disorganization of the contractile apparatus and concomitant loss of contractile function.

Treatment of spinal epidural metastasis improves patient survival and functional state

OBJECTIVES

To determine factors affecting the success of radiation therapy (RT) of spinal epidural metastases and patient survival after RT.

DESIGN/METHODS

One hundred thirty-nine male veterans with an initial spinal epidural metastases treated with dexamethasone and RT were evaluated prospectively. Patients were followed until death.

RESULTS

At presentation, 84 patients could walk. After RT, 119 patients walked. The likelihood of regaining ambulation increased if treatment began <12 hours after loss of ambulation and if patients had bladder and bowel function and sacral sensory sparing. Treatment reduced pain levels, and ambulatory patients had less pain compared with nonambulatory patients. Median length of survival was 104 weeks for ambulatory patients and 6 weeks for nonambulatory patients. Mean interval between loss of ambulation and death was 4.0 +/- 0.5 weeks. Recurrent spinal epidural metastases occurred in 8.63% of patients.

CONCLUSIONS

Patients who walked after treatment lived longer, were ambulatory for most of their remaining life, had less pain, and had a lower incidence of depression.

Neuromuscular manifestations of endocrine disorders

This article reviews the neuromuscular disorders associated with many endocrine disturbances. The severity of neuromuscular disorders varies. Some of these disturbances are mild, and others are severe and life threatening.