Pain expectations in neuropathic pain: Is it best to be optimistic?

BACKGROUND

Pain expectancy may be an important variable that has been found to influence the effectiveness of treatments for pain. Much of the literature supports a self-fulfilment perspective where expectations for pain relief predict the actual pain experienced. However, in conditions such as neuropathic pain (NeP) where pain relief is difficult to attain, expectations for pain relief could be unrealistic. The objective of this study was to investigate the relationship between realistic/unrealistic expectations and 6-month, post-treatment outcomes.

METHODS

We performed a retrospective analysis of a large cohort of patients with NeP (n = 789) attending tertiary care centres to determine the association between unrealistic (both positive and negative) and realistic expectations with outcomes after multidisciplinary treatment. An expectation variable with three categories was calculated: realistic expectations were those whose expected reduction in pain was similar to the observed mean group reduction in pain, while optimistic and pessimistic expectations were those who over- or under-estimated the expected response to treatment, respectively. The association between baseline realistic/unrealistic expectations and 6-month pain-related disability, catastrophizing and psychological distress was assessed.

RESULTS

Univariable analyses suggested that realistic expectations were associated with lower levels of disability, catastrophizing and psychological distress, compared to unrealistic expectations. However, after adjustment for baseline symptom severity, multivariable analysis revealed that patients with optimistic expectations had lower levels of disability, than those with realistic expectations. Those with pessimistic expectations had higher levels of catastrophizing and psychological distress at follow-up.

CONCLUSIONS

These findings are largely congruent with the self-fulfilment perspective to expectations.

SIGNIFICANCE

This study defined realistic pain expectations with patient data. Examining the relationship between expectations between pain and disability in a large cohort of patients with neuropathic pain.

UAS TOPOGRAPHIC MAPPING WITH VELODYNE LiDAR SENSOR

Unmanned Aerial System (UAS) technology is nowadays willingly used in small area topographic mapping due to low costs and good quality of derived products. Since cameras typically used with UAS have some limitations, e.g. cannot penetrate the vegetation, LiDAR sensors are increasingly getting attention in UAS mapping. Sensor developments reached the point when their costs and size suit the UAS platform, though, LiDAR UAS is still an emerging technology. One issue related to using LiDAR sensors on UAS is the limited performance of the navigation sensors used on UAS platforms. Therefore, various hardware and software solutions are investigated to increase the quality of UAS LiDAR point clouds. This work analyses several aspects of the UAS LiDAR point cloud generation performance based on UAS flights conducted with the Velodyne laser scanner and cameras. The attention was primarily paid to the trajectory reconstruction performance that is essential for accurate point cloud georeferencing. Since the navigation sensors, especially Inertial Measurement Units (IMUs), may not be of sufficient performance, the estimated camera poses could allow to increase the robustness of the estimated trajectory, and subsequently, the accuracy of the point cloud. The accuracy of the final UAS LiDAR point cloud was evaluated on the basis of the generated DSM, including comparison with point clouds obtained from dense image matching. The results showed the need for more investigation on MEMS IMU sensors used for UAS trajectory reconstruction. The accuracy of the UAS LiDAR point cloud, though lower than for point cloud obtained from images, may be still sufficient for certain mapping applications where the optical imagery is not useful.

Equivalency of tricyclic antidepressants in open-label neuropathic pain study

OBJECTIVES

To compare adverse effects, tolerability and efficacy of the tricyclic antidepressants (TCAs) amitriptyline and nortriptyline in management of neuropathic pain due to peripheral neuropathy (PN).

MATERIALS & METHODS

We performed a prospective open-label flexible-dosing comparison of monotherapy or adjuvant therapy using amitriptyline or nortriptyline in PN-associated neuropathic pain. Primary outcomes were quantitative adverse effects and discontinuation rates. Secondary outcomes assessed changes in pain severity, quality of life, disability, sleep efficacy, mood and anxiety, and global improvement. Assessments occurred at 3 and 6 months after initiation. Our hypothesis was that nortriptyline would have better tolerance than amitriptyline.

RESULTS

A total of 228 PN patients were enrolled approximately equally for monotherapy and adjuvant therapy. Adverse effects and discontinuation rates were similar between amitriptyline and nortriptyline interventions. Weight gain was more common with amitriptyline, while nortriptyline use was associated with greater prevalence of dry mouth. Secondary outcome measures were similar in both groups, demonstrating improvement from baseline.

CONCLUSIONS

Amitriptyline and nortriptyline are equivalent for overall adverse effects and discontinuation rates. Either TCA should be equally considered for use in neuropathic pain due to PN. When used as monotherapy or as part of adjuvant therapy, either TCA can be expected to provide approximately 23-26% visual analog scale pain reduction if tolerated. Discontinuations due to inefficacy or adverse effects can be anticipated in 26-37% of patients initiated on either TCA for PN-associated neuropathic pain.

Expression of oestrogen receptor β and prognosis of colorectal cancer

BACKGROUND

Previous studies suggest that sex steroids influence colorectal cancer (CRC) carcinogenesis. The oestrogen receptor β (ERβ) is the predominantly expressed ER in the colon and loss of ERβ in CRC has been associated with advanced cancer stages.

METHODS

Information on vital status by the end of 2009 was obtained for 1262 CRC patients recruited between 2003 and 2007. The ERβ expression was immunohistochemically measured and associations of ERβ scores with overall survival (OS), disease-specific survival (DSS) and disease-free survival (DFS) were evaluated using Cox proportional hazard models adjusted for prognostic factors, such as tumour stage and second primary tumours.

RESULTS

Of the 1101 tumour samples with successful measurement, 535 were ERβ negative (48.6%), 381 (34.6%) showed moderate and 185 (16.8%) showed high ERβ expression. Compared with high ERβ expression, lack of ERβ was associated with higher cancer stages as well as greater tumour extent. In multivariate analyses, ERβ negativity was associated with an increased hazard ratio for death (HR=1.61, 95% CI 1.09-2.40, P=0.02), death attributed to CRC (HR=1.54, 95% CI 0.99-2.39, P=0.06) as well as a poorer DFS (DFS HR=1.64, 95% CI 1.23-3.36, P=0.04). The associations were stronger in stage I-III patients (OS HR=2.20, 95% CI 1.28-4.06, P=0.007, DSS HR=2.38, 95% CI 1.20-5.39, P=0.02, respectively).

CONCLUSIONS

Lack of ERβ expression is associated with advanced cancer stages and independently associated with poor survival.

Calibration of a microchannel plate based extreme ultraviolet grazing incident spectrometer at the Advanced Light Source

We present the design and calibration of a microchannel plate based extreme ultraviolet spectrometer. Calibration was performed at the Advance Light Source (ALS) at the Lawrence Berkeley National Laboratory (LBNL). This spectrometer will be used to record the single shot spectrum of radiation emitted by the tapered hybrid undulator (THUNDER) undulator installed at the LOASIS GeV-class laser-plasma-accelerator. The spectrometer uses an aberration-corrected concave grating with 1200 lines/mm covering 11-62 nm and a microchannel plate detector with a CsI coated photocathode for increased quantum efficiency in the extreme ultraviolet. A touch screen interface controls the grating angle, aperture size, and placement of the detector in vacuum, allowing for high-resolution measurements over the entire spectral range.

Adverse effects of corticosteroid therapy in neuromuscular diseased patients are common and receive insufficient prophylaxis

BACKGROUND

Corticosteroid therapy is known to have long-term adverse effects and complications, but our knowledge of the adverse effects of corticosteroids within a neuromuscular patient population is limited.

AIMS OF THE STUDY

We sought to determine the prevalence and impact of corticosteroid use in a population of patients with neuromuscular diseases, as well as possible clinical associations for presence of adverse effects.

METHODS

A retrospective chart review from a comprehensive database from a tertiary care neuromuscular clinic spanning 1988-2007 was performed.

RESULTS

Corticosteroids led to adverse effects in 74% of exposed patients, without proper prophylaxis considered in about 50% of cases. There were no associations determined to have impact upon adverse effect occurrence, including the exposure to cumulative corticosteroid dosing or diagnosis.

CONCLUSION

Corticosteroid therapy is frequently associated with adverse effects, although prediction of their occurrence is not clear. Prophylaxis of their occurrence is underperformed in our tertiary care clinic patient population.

Poor tolerability of high dose ascorbic acid in a population of genetically confirmed adult Charcot-Marie-Tooth 1A patients

BACKGROUND

Preclinical studies have suggested that ascorbic acid (AA) treatment in a mouse model of Charcot-Marie-Tooth type 1A (CMT1A) improves motor function and prolongs lifespan.

AIMS

I sought to determine the safety and tolerability of AA in adult patients with CMT1A.

METHODS

An open-label cohort-controlled 2-year pilot study was used to evaluate the tolerability of 5 g of AA daily. Secondary measurements consisted of clinical and electrophysiological measurements at 0, 12, and 24 months in CMT1A patients.

RESULTS

Twelve CMT1A patients received AA and 10 CMT1A patients formed a cohort group followed in identical manner. Five (42%) patients tolerated this dose of AA for the entire 2-year span, with six patients (50%) developing intolerable gastrointestinal side effects. No significant differences in clinical, disability, or electrophysiological measurements occurred between baseline and final follow-up in patients receiving AA when compared with cohorts.

CONCLUSIONS

High dose AA was not well tolerated in all adult CMT1A patients who may be susceptible to gastrointestinal adverse effects of AA. Studies with greater powers to detect efficacy will be required to test the validity of AA as a therapy in CMT1A patients. Doses lower than 5 g of AA daily may be required for maintenance of tolerability in the CMT1A population.

Neuronal Targeting in Diabetes Mellitus: A Story of Sensory Neurons and Motor Neurons

Diabetes mellitus targets the peripheral nervous system in unique but disabling ways. Although several mechanisms may target peripheral neurons, they render a degenerative pattern of damage that begins in distal terminals. Moreover, sensory neurons are involved early, motor neurons later. By studying a variety of diabetic neuropathy models in rats, mice, and other species, an overall appreciation of its neurodegeneration emerges. Understanding how mechanisms of diabetes complications target peripheral neurons selectively may offer opportunities to intervene before irretrievable neuron loss develops.NEUROSCIENTIST 14(4):311–318, 2008. DOI: 10.1177/1073858408316175

Dramatic MRI improvement with refractory neurosarcoidosis treated with infliximab

BACKGROUND

Neurosarcoidosis is often a devastating, refractory condition without definite pharmacotherapies beyond corticosteroids.

AIM

To describe a case of steroid-refractory neurosarcoidosis with a marked clinical and radiological response to infliximab.

METHODS

We describe the case of a young female patient with biopsy-proven neurosarcoidosis leading to gait failure. She described significant corticosteroid-related side effects without clinical response to the therapy. Infliximab therapy was considered as a possible rescue medication.

RESULTS

Within months of starting intravenous infliximab therapy, she regained her ability to walk and magnetic resonance imaging identified significant improvements over a sustained course of infliximab therapy, including loss of enhancing nodules and loss of meningeal enhancement.

CONCLUSION

Mounting evidence suggests that infliximab is a valuable pharmacological agent in the management of patients with refractory and disabling neurosarcoidosis. Controlled studies of infliximab in this condition are needed.

[Fracture of the intercondylar eminence of the tibia type II in children: 20 surgically-treated cases]

PURPOSE OF THE STUDY

The purpose of this study was to detail therapeutic indications for fractures of the intercondylar eminence of the tibia with little displacement and preservation of the posterior hinge (type II fracture in the Zarincznyj classification).

MATERIAL AND METHODS

We reviewed retrospectively a multicentric serie of type II fractures of the intercondylar eminence observed in children treated surgically. There were twenty patients, ten girls and ten boys, mean age 11.9 years (range 6-16). Imaging included plain x-rays of the knee (anteroposterior and lateral views) in all patients as well as computed tomography (5 patients) and magnetic resonance imaging (1 patient). Surgical treatment was performed in all cases, on average six days after trauma (range 0-25). A medial parapatellar arthrotomy was used in all cases. A non-resorbable thread was used for fixation associated with an anchor in the last four cases. Clinical and radiological assessment was reviewed at mean 3.7 years follow-up.

RESULTS

All children had resumed their sports activities at the same level as before the accident within 4.8 months on average. None of the children suffered from an unstable knee or functional impairment at last follow-up. The Lysholm score was 88.9 on average (range 70-100) at three months postoperative and 99.2 (range 89-100) at last follow-up.

DISCUSSION

There is currently agreement that non-displaced fractures of the anterior intercondylar eminence of the tibia should be treated orthopedically and that forms with displacement require surgery. Conversely, the type II fractures with an anterior gap but a preserved posterior hinge, the appropriate treatment remains a subject of debate. In our experience, surgery would appear to be preferable to orthopedic management. Surgery enables putting correct tension on the anterior crucicate ligament and limits the risk of residual laxity which, even though rarely associated with instability, could in the long-term lead to osteoathritic degradation or meniscal damage.

CONCLUSION

Surgical treatment of fractures of the intercondylar eminence of the tibia with little displacement and preservation of the posterior hinge provides satisfactory results and the best guarantee of long-term stability.

Acetylcholine receptor antibodies in myasthenia gravis are associated with greater risk of diabetes and thyroid disease

OBJECTIVE

Myasthenia gravis (MG) may be associated with the presence of acetylcholine receptor antibodies (AChRAb) [seropositive MG (SPMG)] or their absence [seronegative MG (SNMG)]. Along with features of MG, the presence of the AChRAb may relate to the existence of other immune-mediated diseases. We sought to determine the association of SPMG with other potential autoimmune diseases.

METHODS

A retrospective evaluation of prospectively identified MG patients at a tertiary care center was performed, with patients separated into SPMG and SNMG. Prevalence of other immune-mediated disorders, as well as the epidemiology, sensitivity of diagnostic testing, and thymic pathology, was contrasted between both patient groups.

RESULTS

Of the 109 MG patients identified, 66% were SPMG. SPMG was associated with a greater likelihood of significant repetitive stimulation decrement, the presence of either thymoma or thymic hyperplasia, and the presence of thyroid disease. In addition, all patients with a diagnosis of diabetes, concurrent with MG, were found to be SPMG.

CONCLUSIONS

AChRAb and SPMG impart not only a distinctive clinical and electrophysiological phenotype of MG, but are also associated with the heightened presence of endocrinological disease.

Remote neurotrophic support of epidermal nerve fibres in experimental diabetes

AIMS/HYPOTHESIS

The support of distal regenerating axons and epidermal nerve fibres through growth factor delivery may depend on the site of delivery. While low-dose systemic insulin provides trophic support for regenerating axons or axons from diabetic animals, its potential action upon the most distal neurites within the epidermis is unknown. In diabetic neuropathy, distal loss of axons is an important clinical and pathological feature. We hypothesised that insulin and IGF-1 delivered intrathecally could support the most distal epidermal nerve fibres.

MATERIALS AND METHODS

As insulin and IGF-1 receptors are present upon sensory ganglion perikarya, we studied the impact of intrathecal delivery of low-dose insulin and equimolar IGF-1 on the density of epidermal axons expressing protein gene product 9.5 in experimental diabetic rats. After 2 months of diabetes induced by streptozotocin injection, intrathecal delivery of low-dose insulin or IGF-1 or saline was provided for 1 month, with comparison to compatible doses of subcutaneous insulin delivery.

RESULTS

Diabetes, in itself, was associated with a decline in epidermal nerve fibre density. Delivery of both intrathecal IGF-1 and insulin was associated with significant improvement in epidermal fibre density (greatest with IGF-1) and length relative to placebo.

CONCLUSIONS/INTERPRETATION

Central intrathecal delivery of IGF-1 and insulin offers remote support for epidermal nerve fibres, subjected to 'dying-back' in early diabetic polyneuropathy.

Rescue and regeneration of injured peripheral nerve axons by intrathecal insulin

Insulin peptide, acting through tyrosine kinase receptor pathways, contributes to nerve development or repair. In this work, we examined the direction, impact and repertoire of insulin signaling in vivo during peripheral nerve regeneration in rats. First, we demonstrated that insulin receptor is expressed on lumbar dorsal root ganglia neuronal perikarya using immunohistochemistry. Immunoblots and polymerase chain reactions confirmed the presence of both alpha and beta insulin receptor subunits in dorsal root ganglia. In vivo and in vitro assessment of dorsal root ganglion neurons showed preferential localization of insulin receptor to perikaryal sites. In vivo, intrathecal delivery of fluorescein isothiocyanate-labeled insulin identified localization around dorsal root ganglia neurons. The direction and impact of potential insulin signaling was evaluated by concurrently delivering insulin or carrier over a 2 week period using mini-osmotic pumps, either intrathecally, near nerve, or with both deliveries, following a selective sural nerve crush injury. Only intrathecal insulin increased the number and maturity of regenerating sensory sural nerve axons distal to the crush site. As well, only intrathecal insulin rescued retrograde loss of sural axons after crush. In a separate experiment, insulin also rescued retrograde loss and atrophy of deep peroneal, largely motor, axons post-injury. Intrathecal insulin increased the expression of calcitonin-gene-related peptide in regenerating sprouts, increased the number of visualized regenerating fiber clusters, and reduced downregulation of calcitonin-gene-related peptide in dorsal root ganglia neurons. Insulin delivered intrathecally does not appear to influence expression of insulin-like growth factor-1 at dorsal root ganglion neurons or near peripheral nerve injury, but was associated with upregulation of insulin receptor alpha subunit in dorsal root ganglia. Intrathecal insulin delivery was associated with greater recovery of thermal sensation and longer distances to stimulus response with the pinch test following sural nerve crush. Insulin signaling at neuron perikarya can drive distal sensory axon regrowth, rescue retrograde alterations of axons and alter axon peptide expression. Moreover, such actions are associated with upregulation of its own receptor.

Diabetes Mellitus and the Sensory Neuron

Sensory neurons in diabetes may be primarily targeted by diabetes and their involvement may account for prominent sensory loss and pain in diabetic patients. Previous studies demonstrating evidence of excessive polyol flux, microangiopathy, and oxidative stress involving sensory axons and ganglia have been joined by more recent work demonstrating altered neuron phenotype, mitochondrial dysfunction, ion channel alterations, and abnormal growth factor signaling. As such, an interesting and unique panoply of molecular changes in primary sensory neurons has been identified in diabetic models. Insulin deficiency and subsequent changes in second messenger signaling may also play an important role in how sensory neurons respond to diabetes. Applying approaches to support sensory neurons in diabetes may be an important therapeutic direction in diabetic patients.

Hemisensory syndrome is associated with a low diagnostic yield and a nearly uniform benign prognosis

OBJECTIVE

To describe the diagnostic yield and prognosis for patients with hemisensory syndrome.

BACKGROUND

The aetiology, utility of diagnostic procedures, and outcome of hemisensory syndrome in patients with exclusive hemibody complaints having only subjective sensory abnormalities on examination is unknown.

METHODS

Patients were prospectively identified with hemisensory syndrome in a tertiary care institution from 1998-2002. Diagnostic procedures were analysed for sensitivity and clinical follow up was performed.

RESULTS

Thirty four patients, 25 (74%) women, of age 35 (SD 11) years were identified. The hemisensory syndrome occurred on the left side in 23 (68%) cases. Neuroimaging of the brain demonstrated diagnostic abnormalities representing ischaemic aetiology in one case. Other diagnostic testing including cerebrospinal fluid examination, electrophysiological testing, carotid ultrasonography, echocardiography, and blood testing revealed no diagnostic abnormalities. Sixteen patients (47%) continued to complain of hemisensory difficulties after all investigations were completed at 9.6 (5.8) days. One patient with a history of systemic lupus erythematosus and positive antiphospholipid antibodies had a second event diagnosed as stroke seven months after presentation. Clinical follow up at 16 (7) months revealed persisting symptoms in 6 (20%) of 30 patients. Six (50%) of 12 patients agreeing to psychiatric assessment received diagnoses of personality or mood disorders.

CONCLUSIONS

Diagnostic yield in hemisensory syndrome is low, and prognosis is almost always uniformly benign. The author advocates careful assessment of medical history and consideration for neuroimaging in this group of patients.

Electron-yield enhancement in a laser-wakefield accelerator driven by asymmetric laser pulses

The effect of asymmetric laser pulses on electron yield from a laser wakefield accelerator has been experimentally studied using >10(19) cm(-3) plasmas and a 10 TW, >45 fs, Ti:Al2O3 laser. The laser pulse shape was controlled through nonlinear chirp with a grating pair compressor. Pulses (76 fs FWHM) with a steep rise and positive chirp were found to significantly enhance the electron yield compared to pulses with a gentle rise and negative chirp. Theory and simulation show that fast rising pulses can generate larger amplitude wakes that seed the growth of the self-modulation instability, and that frequency chirp is of minimal importance for the experimental parameters.

Supportive and palliative care: experience at the Institut Jules Bordet

The Supportive and Palliative Care Unit of the Institut Jules Bordet officially started its activities in February 1999. Our Unit comprises eight beds (four rooms with one bed each and two rooms with two beds each). We admit advanced cancer patients presenting with severe symptoms whose control is going to require all the expertise of a multidisciplinary team. Whilst these eight beds are identified geographically in the hospital, the team's mobility assures continuity of care for patients who wish to stay in another department. The infrastructure of the Unit and its rooms allow close family members who wish to sleep close to the patients to do so. Otherwise, visits are allowed round the clock, though always with due consideration for patients' comfort. Patients are referred either by a physician working in our Institution (medical oncologist, surgeon, or radiotherapist) or by their family physicians. Less frequently, patients themselves specifically ask to be admitted to our Unit. The activity of the Unit itself during its first year of functioning can be summarized as follows. We admitted 155 advanced cancer patients, for a total number of 210 hospitalizations. Patients were admitted a median of 35 months after their diagnosis and a median of 20 days before death. Stays were generally short (median 11 days). We systematically used quantitative assessment tools (MMSQ, MDAS,EFAT and various VAS) to detect and monitor their symptoms and any complications. The main symptoms on admission were pain, anorexia, asthenia, dyspnea and anxiety/depression. Pain, nausea/vomiting, constipation and cough were controlled in almost all patients, whereas control of asthenia and anorexia was most often insufficient. In 51% of our cases the patients could be discharged home; 40% died in the unit; 4% were transferred to long-term palliative care units and 1% to other units within our Institution (4% were still hospitalized at the time of this analysis).

Mandibular reconstruction with prefabricated vascularized bone grafts using recombinant human osteogenic protein-1: an experimental study in miniature pigs. Part II: transplantation

Osteogenic Protein-1 (rhOP-1), also called bone morphogenetic protein-7 (BMP-7), is osteoinductive. The aim of this study was to present a new surgical technique: the prefabrication of a vascularized bone graft using rhOP-1 and its microsurgical transplantation. During 6 weeks, osteomuscular grafts were prefabricated in the latissimus dorsi muscle of five adult minipigs. Six hundred micrograms rhOP-1 on a carrier of xenogenic bone mineral in block form were used. The grafts were transplanted into defects of the mandibular angles performing a microsurgical anastomosis and using miniplates for fixation. Identical defects of the contralateral side were treated by direct application of 600 microg rhOP-1 and xenogenic bone mineral. A polychrome sequential labelling was applied. After transplantation the bone stayed viable, demonstrated by continuous apposition of fluorochromes (non-decalcified histologic sections) and bone scintigraphy. The reconstructive result was significantly superior in the prefabrication technique, assessed by histology and computerized tomography (CT). In conclusion, the method has a potential to become a clinical alternative for conventional vascularized bone grafts.

Wernicke's encephalopathy following gastroplasty for morbid obesity

BACKGROUND

The syndrome of Wernicke's encephalopathy consists of two of four features of (1) dietary deficiency; (2) oculomotor abnormality; (3) cerebellar dysfunction; and (4) confusion or mild memory impairment. Predisposing risk factors include alcoholism, hyperemesis gravidarum and prolonged intravenous feeding.

METHODS

A 35-year-old female developed refractory emesis, severe weight loss, and hypokalemia following banded gastroplasty for morbid obesity. Reversal of gastroplasty was performed four months following initial surgery. Following reversal, the patient developed confusion, ataxia, leg weakness and nystagmus.

RESULTS

Examination of the patient demonstrated disorientation with confusion, vertical nystagmus worse on downgaze, diffuse weakness of the lower extremities, and bilateral dysmetria. Magnetic resonance imaging of the brain demonstrated symmetrical areas of increased T2 signal present bilaterally in the medial thalamic nuclei. The patient did not demonstrate any initial improvement with intravenous thiamine but improved over two months of follow-up.

CONCLUSION

Wernicke's encephalopathy has been reported in the European literature as a complication of gastroplasty, with rare recognition of this clinical entity in the North American literature. This potential complication of gastroplasty may be preventable by nutritional intervention in subjects experiencing severe weight loss and emesis following surgery.

Deep brain stimulation of the ventral intermediate nucleus of the thalamus for control of tremors in Parkinson's disease and essential tremor

The beneficial effects of ventral intermediate nucleus (VIM) stimulation were evaluated in 20 patients with tremor refractory to medical therapy. Thalamic stimulation is a non-ablative procedure which has the advantage of a reversible, non-destructive lesion. Eleven patients [7 with Parkinson's disease (PD) and 4 with essential tremor (ET)] received unilateral VIM implantation, while 9 patients had staged bilateral VIM implantation (4 with PD, 5 with ET). PD patients showed a significant improvement in contralateral arm and leg rest tremor and ipsilateral leg rest tremor (p < 0.02) at a mean follow-up period of 16.2 +/- 7.0 months. Patients with PD did not demonstrate any significant decrease in medication use at follow-up. ET patients demonstrated significant improvement in postural and action tremor in the contralateral arm (p < 0.001), but no significant improvement in the contralateral leg tremor at follow-up. Significant improvements were also seen in ET patients in the Clinical Rating Scale for Tremor (p < 0.001) with respect to several activities of daily living at a mean follow-up of 14.9 +/- 8. 1 months. Deep brain stimulation is a safe and effective treatment for severe tremor refractory to medications. It is a highly effective, reversible, adaptable, and predictable procedure which avoids the complication of cognitive deficit seen in patients with bilateral thalamotomies.

A 50 EW/cm;2 Ti:sapphire laser system for studying relativistic light-matter interactions

A 10-Hz repetition rate, 60-TW peak power, Ti:sapphire laser system was developed for use in experiments where relativistic effects dominate the physics. The temporal, spectral, energy and spatial characteristics of the laser pulses were measured in single shot format. The pulse duration ranged from 22 fs to 25 fs and the pulse energy averaged 1.3 J. Atomic photoionization measurements quantified the peak intensity of the laser pulse in situ. The measurements indicated an intensity of at least 510 19 W/cm 2 was produced.

Regulated degradation of yeast ornithine decarboxylase

Ornithine decarboxylase (ODC) declines in cells that accumulate an excess of polyamines, the downstream products of the enzyme. Superfluous production of polyamines is thus prevented. In animal cells, polyamines reduce ODC activity by accelerating its degradation. Similar down-regulation of ODC activity has been observed in the budding yeast Saccharomyces cerevisiae, but induced degradation has not been documented. Here we show using pulse-chase analysis that the loss of enzyme activity is the result of increased degradation of ODC. Polyamines reduce the half-life of the newly synthesized protein from 3 h to approximately 10 min. Degradation of bulk ODC pools is also accelerated by polyamines, but the absolute rate of turnover is slower, with a half-life of 5 h in untreated and 1 h in treated cells. Newly synthesized ODC polypeptide thus undergoes a process of maturation that renders it relatively resistant to both basal and polyamine-induced degradation. Proteasome mutants have a blunted or absent regulatory response, implicating both the core protease and the regulatory cap of the proteasome in induced degradation of yeast ODC.

Stereotactic cyst wall disruption and aspiration of colloid cysts of the third ventricle

BACKGROUND

Current strategies of surgical therapy for colloid cysts have been associated with low rates of initial success and high rates of morbidity, mortality and recurrence of cysts. Cyst recurrence following simple stereotactic aspiration has been hypothesized to be due to regrowth of the epithelium composing the cyst wall.

METHODS

We propose a procedure involving stereotactic disruption of the colloid cyst wall with the removal of a portion of the cyst wall followed by aspiration of cyst contents as a surgical therapy for colloid cysts.

RESULTS

This procedure was performed in 2 female and 3 male patients who were followed for an average of 49 months with all patients demonstrating immediate improvement of symptoms and resolution of the cyst verified with repeat computerized tomography (CT) scans. There was one incidence of recurrence in an asymptomatic patient at 75 months postoperatively.

CONCLUSION

We propose that stereotactic partial cyst wall disruption and content aspiration may limit recurrence of colloid cysts, thus offering an advantage over simple stereotactic aspiration alone.

Indoor, outdoor, and regional summer and winter concentrations of PM10, PM2.5, SO4(2)-, H+, NH4+, NO3-, NH3, and nitrous acid in homes with and without kerosene space heaters

Twenty-four-hour samples of PM10 (mass of particles with aerodynamic diameter < or = 10 microm), PM2.5, (mass of particles with aerodynamic diameter < or = 2.5 microm), particle strong acidity (H+), sulfate (SO42-), nitrate (NO3-), ammonia (NH3), nitrous acid (HONO), and sulfur dioxide were collected inside and outside of 281 homes during winter and summer periods. Measurements were also conducted during summer periods at a regional site. A total of 58 homes of nonsmokers were sampled during the summer periods and 223 homes were sampled during the winter periods. Seventy-four of the homes sampled during the winter reported the use of a kerosene heater. All homes sampled in the summer were located in southwest Virginia. All but 20 homes sampled in the winter were also located in southwest Virginia; the remainder of the homes were located in Connecticut. For homes without tobacco combustion, the regional air monitoring site (Vinton, VA) appeared to provide a reasonable estimate of concentrations of PM2.5 and SO42- during summer months outside and inside homes within the region, even when a substantial number of the homes used air conditioning. Average indoor/outdoor ratios for PM2.5 and SO42- during the summer period were 1.03 +/- 0.71 and 0.74 +/- 0.53, respectively. The indoor/outdoor mean ratio for sulfate suggests that on average approximately 75% of the fine aerosol indoors during the summer is associated with outdoor sources. Kerosene heater use during the winter months, in the absence of tobacco combustion, results in substantial increases in indoor concentrations of PM2.5, SO42-, and possibly H+, as compared to homes without kerosene heaters. During their use, we estimated that kerosene heaters added, on average, approximately 40 microg/m3 of PM2.5 and 15 microg/m3 of SO42- to background residential levels of 18 and 2 microg/m3, respectively. Results from using sulfuric acid-doped Teflon (E.I. Du Pont de Nemours & Co., Wilmington, DE) filters in homes with kerosene heaters suggest that acid particle concentrations may be substantially higher than those measured because of acid neutralization by ammonia. During the summer and winter periods indoor concentrations of ammonia are an order of magnitude higher indoors than outdoors and appear to result in lower indoor acid particle concentrations. Nitrous acid levels are higher indoors than outdoors during both winter and summer and are substantially higher in homes with unvented combustion sources.

Indoor, outdoor, and regional summer and winter concentrations of PM10, PM2.5, SO4(2)-, H+, NH4+, NO3-, NH3, and nitrous acid in homes with and without kerosene space heaters

Twenty-four-hour samples of PM10 (mass of particles with aerodynamic diameter < or = 10 microm), PM2.5, (mass of particles with aerodynamic diameter < or = 2.5 microm), particle strong acidity (H+), sulfate (SO42-), nitrate (NO3-), ammonia (NH3), nitrous acid (HONO), and sulfur dioxide were collected inside and outside of 281 homes during winter and summer periods. Measurements were also conducted during summer periods at a regional site. A total of 58 homes of nonsmokers were sampled during the summer periods and 223 homes were sampled during the winter periods. Seventy-four of the homes sampled during the winter reported the use of a kerosene heater. All homes sampled in the summer were located in southwest Virginia. All but 20 homes sampled in the winter were also located in southwest Virginia; the remainder of the homes were located in Connecticut. For homes without tobacco combustion, the regional air monitoring site (Vinton, VA) appeared to provide a reasonable estimate of concentrations of PM2.5 and SO42- during summer months outside and inside homes within the region, even when a substantial number of the homes used air conditioning. Average indoor/outdoor ratios for PM2.5 and SO42- during the summer period were 1.03 +/- 0.71 and 0.74 +/- 0.53, respectively. The indoor/outdoor mean ratio for sulfate suggests that on average approximately 75% of the fine aerosol indoors during the summer is associated with outdoor sources. Kerosene heater use during the winter months, in the absence of tobacco combustion, results in substantial increases in indoor concentrations of PM2.5, SO42-, and possibly H+, as compared to homes without kerosene heaters. During their use, we estimated that kerosene heaters added, on average, approximately 40 microg/m3 of PM2.5 and 15 microg/m3 of SO42- to background residential levels of 18 and 2 microg/m3, respectively. Results from using sulfuric acid-doped Teflon (E.I. Du Pont de Nemours & Co., Wilmington, DE) filters in homes with kerosene heaters suggest that acid particle concentrations may be substantially higher than those measured because of acid neutralization by ammonia. During the summer and winter periods indoor concentrations of ammonia are an order of magnitude higher indoors than outdoors and appear to result in lower indoor acid particle concentrations. Nitrous acid levels are higher indoors than outdoors during both winter and summer and are substantially higher in homes with unvented combustion sources.

Epidural spinal cord stimulation for treatment of chronic pain--some predictors of success. A 15-year experience

BACKGROUND

We have used epidural spinal cord stimulation (SCS) for pain control for the past 15 years. An analysis of our series of 235 patients has clarified the value of specific prognostic parameters in the prediction of successful SCS.

METHODS

Patients were followed up for periods ranging from 6 months to 15 years with a mean follow-up of 66 months. The mean age of the 150 men and 85 women in the study was 51.4 years. Indications for SCS included failed back syndrome (114 patients), peripheral vascular disease (39 patients), peripheral neuropathy (30 patients), multiple sclerosis (13 patients), reflex sympathetic dystrophy (13 patients), and other etiologies of chronic intractable pain (26 patients).

RESULTS

One hundred and eighty-nine patients received permanent devices; 111 (59%) of these patients continue to receive satisfactory pain relief. Pain attributable to failed back syndrome, reflex sympathetic dystrophy, peripheral vascular disease of lower limbs, multiple sclerosis, and peripheral neuropathy responded favorably to spinal cord stimulation. In contrast, paraplegic pain, cauda equina syndrome, stump pain, phantom limb pain, and primary bone and joint disease pain did not respond as well. Cases of cauda equina injury had promising initial pain relief, but gradually declined after a few years. After long-term follow-up, 47 of the 111 successfully implanted patients were gainfully employed, compared with 22 patients before implantation. The successful patients reported improvements in daily living as well as a decrease in analgesic usage. Multipolar stimulation systems were significantly more reliable (p < 0.001) than unipolar systems. Complications included hardware malfunction, electrode displacement, infection, and tolerance.

CONCLUSION

Aside from etiologies of pain syndromes as a prognostic factor, we have identified other parameters of success. In patients who have undergone previous surgical procedures, the shorter the duration of time to implantation, the greater the rate of success (p < 0.001). The diagnosis of failed back syndrome must be considered a confounding factor in our analysis. Those patients whose pain did not follow a surgical procedure had better responses to SCS than patients who had multiple surgical procedures prior to their first implant. The advent of multipolar systems has significantly improved clinical reliability over unipolar systems. Age, sex, and laterality of pain did not prove to be of significance.

Focal plaque of demyelination mimicking cerebral tumor in a pediatric patient

Focal, demyelinating lesions of the cerebrum mimicking brain tumors are a rare phenomenon, and even rarer in a pediatric population. We document the case of a 14-year-old female whose clinical, radiological and operative findings were strongly suggestive of glioma. However, histopathology revealed a demyelinating process. This case is significant as the lesion could not be distinguished from a glioma at any time in the presentation. At 41 months follow-up, the patient remains stable without further evidence of demyelination in other areas of the brain. Such a case suggests a cautious note for the pediatrician when presented with a similar patient and illustrates the importance of consideration of a demyelinating lesion in the differential diagnosis of a mass lesion in a pediatric population.