Interpretation of Post-operative Distal Humerus Radiographs After Internal Fixation: Prediction of Later Loss of Fixation

PURPOSE

Stable fixation of distal humerus fracture fragments is necessary for adequate healing and maintenance of reduction. The purpose of this study was to measure the reliability and accuracy of interpretation of postoperative radiographs to predict which implants will loosen or break after operative treatment of bicolumnar distal humerus fractures. We also addressed agreement among surgeons regarding which fracture fixation will loosen or break and the influence of years in independent practice, location of practice, and so forth.

METHODS

A total of 232 orthopedic residents and surgeons from around the world evaluated 24 anteroposterior and lateral radiographs of distal humerus fractures on a Web-based platform to predict which implants would loosen or break. Agreement among observers was measured using the multi-rater kappa measure.

RESULTS

The sensitivity of prediction of failure of fixation of distal humerus fracture on radiographs was 63%, specificity was 53%, positive predictive value was 36%, the negative predictive value was 78%, and accuracy was 56%. There was fair interobserver agreement (κ = 0.27) regarding predictions of failure of fixation of distal humerus fracture on radiographs. Interobserver variability did not change when assessed for the various subgroups.

CONCLUSIONS

When experienced and skilled surgeons perform fixation of type C distal humerus fracture, the immediate postoperative radiograph is not predictive of fixation failure. Reoperation based on the probability of failure might not be advisable.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic III.

Amputation in patients with complex regional pain syndrome: a comparative study between amputees and non-amputees with intractable disease

AIMS

Amputation in intractable cases of complex regional pain syndrome (CRPS) remains controversial. The likelihood of recurrent Complex Regional Pain Syndrome (CRPS), residual and phantom limb pain and persistent disability after amputation is poorly described in the literature. The aims of this study were to compare pain, function, depression and quality of life between patients with intractable CRPS who underwent amputation and those in whom amputation was considered but not performed.

PATIENTS AND METHODS

There were 19 patients in each group, with comparable demographic details. The amputated group included 14 men and five women with a mean age of 31 years (sd 12) at the time of CRPS diagnosis. The non-amputated group consisted of 12 men and seven women and their mean age of 36.8 years (sd 8) at CRPS diagnosis. The mean time from CRPS diagnosis to (first) amputation was 5.2 years (sd 4.3) and the mean time from amputation to data collection was 6.6 years (sd 5.8). All participants completed the following questionnaires: Short-Form (SF) 36, Short Form McGill Pain questionnaire (SF-MPQ), Pain Disability Index (PDI), the Beck Depression Inventory (BDI) and a clinical demographic questionnaire.

RESULTS

The amputation group showed consistently better results compared to the non-amputation group in the following parameters: median pain intensity (VAS): 80 (inter-quartile range (IQR) 13 to 92) vs 91 (IQR 85 to 100); p = 0.007; median SF-MPQ score 28 (IQR 9 to 35) vs 35 (IQR 31 to 38), p = 0.025; median PDI: 42 (IQR 11 to 64) vs 58 (IQR 50 to 62), p = 0.031; median BDI: 19 (IQR 5 to 28) vs 27 (IQR 21 to 32), p = 0.061 (borderline significant) and in six of the eight SF-36 domains.

TAKE HOME MESSAGE

Amputation should be considered as a form of treatment for patients with intractable CRPS.

Therapeutic effect of myogenic cells modified to express neurotrophic factors in a rat model of sciatic nerve injury

Sciatic nerve injury may cause neurological deficits, particularly muscle weakness. Previous studies have shown that administration of neurotrophic factors (NTFs), naturally occurring proteins that support the development and survival of neurons, partially protected the damaged motor neuron in the injured sciatic nerve. In the current study, we have examined whether the administration of various combinations of transfected muscle progenitor cells (MPCs) populations, each expressing a single NTF (BDNF, GDNF, IGF-1 or VEGF) or conditioned media of such culture are capable of rescuing motor neurons in culture or in vivo. We have found that the mixture of conditioned media collected from cultured myogenic cells (MPCs- MIX⁺) alleviated the toxic effect of exposure of the motor neuron cell line NSC34 to hypoxic environment. Furthermore, NTFs secreting cells transplantation, protected motor neurons in a unilateral rat sciatic nerve injury model: One day after the crush, rats underwent transplantation at the lesion site with rat myogenic cells expressing one of the four NTFs; a mixture of cells expressing all four NTFs (MPCs- MIX⁺), MPCs-GFP or PBS. We found that in rats injected with MPCs- MIX⁺ the motor function was markedly preserved, compared to groups injected with cells secreting a single NTF, GFP or PBS. Transplantation of the MPCs- MIX⁺ significantly inhibited the degeneration of the neuromuscular junctions and enhanced the survival of the myelinated motor axons. The injection of MPCs- MIX⁺ preserved the compound muscle action potential (CMAP) as was demonstrated by motor nerve conduction studies. Our findings suggest that MPCs induced to secrete several NTFs can synergistically alleviate symptoms of sciatic nerve injury and perhaps other motor neuron disorders..

Contribution of genetic variants to pain susceptibility in Parkinson disease

BACKGROUND

Pain is a one of the most disturbing non-motor symptoms of Parkinson disease (PD). The susceptibility to pain varies substantially among patients with PD. The aim of this study was to assess a potential association of genetic variants to PD-related pain.

METHODS

We analysed 20 candidate SNPs from 12 genes previously reported to be associated with various pain phenotypes in a homogeneous group of 229 Israeli Jewish PD patients, with and without pain (n = 165 and 64, respectively).

RESULTS

The statistical analysis accounted for the potential influence of demographic and clinical factors. The non-synonymous rs6746030 single nucleotide polymorphism (SNP) of the SCN9A gene, which alters the coding sequence of the sodium channel Nav1.7 (arginine to tryptophan), was nominally associated with PD-related pain susceptibility (p = 0.037), as well as with central and musculoskeletal pain subtypes independently. The synonymous rs324419 SNP of the FAAH gene which encodes fatty acid amide hydrolase, a cannabinoid metabolizing enzyme, was associated with PD-related pain (p = 0.006) and specifically with the musculoskeletal subtype. The FAAH haplotype of rs324419 and rs2295633 SNPs, which was previously associated with the variability in pain response in humans, was also associated with PD-related pain (p = 0.012) and specifically with PD-related musculoskeletal pain.

CONCLUSIONS

Variants within in the SCN9A and FAAH genes were associated with the risk of pain in PD patients. These findings may contribute to our understanding of pain mechanisms of PD and to direct future therapies.

High prevalence of malignant melanoma in Israeli patients with Parkinson's disease

The risk of melanoma is higher in patients with Parkinson's disease (PD) than in the general population. Whether the association is disease related or treatment related is unclear. The objective of this study was to assess melanoma prevalence in PD patients in Israel using active dermatologic screening. Consecutive patients with idiopathic PD were recruited by 12 Israeli centers. A movement disorder specialist assessed the severity of PD and obtained a medical, neurological, and medication history. Subsequently, a dermatologist assessed melanoma risk factors, recorded a dermatologic history, proactively performed a whole-body skin examination, and biopsied suspicious skin lesions. Of the enrolled patients (n = 1,395, mean age 69.5 ± 10.6 years, mean PD duration 7.3 ± 6.0 years), 95.3% were treated with dopaminergic agents. Biopsies revealed 8 patients with melanoma in situ and 1 with invasive malignant melanoma; 14 patients reported a melanoma prior to enrollment. The observed 5-year limited duration prevalence of melanoma in PD patients was 4.4 times greater (95% CI 2.6-7.6) than expected from melanoma prevalence in an age- and sex-matched cohort from the Israel National Cancer Registry. The increase was accounted for by an elevated prevalence of melanoma in situ [relative risk 12.5 (95% CI 6.7-23.2)]. Occurrence of melanoma did not correlate with levodopa therapy or time of onset of PD. Melanoma prevalence in PD patients was higher than expected in the general Israeli population. This was not related to levodopa treatment. PD patients should be actively screened for melanoma on a routine basis.

Regenerative effect of neural-induced human mesenchymal stromal cells in rat models of Parkinson's disease

BACKGROUND

Human bone marrow multipotent mesenchymal stromal cells (hMSC), because of their capacity of multipotency, may provide an unlimited cell source for cell replacement therapy. The purpose of this study was to assess the developmental potential of hMSC to replace the midbrain dopamine neurons selectively lost in Parkinson's disease.

METHODS

Cells were isolated and characterized, then induced to differentiate toward the neural lineage. In vitro analysis of neural differentiation was achieved using various methods to evaluate the expression of neural and dopaminergic genes and proteins. Neural-induced cells were then transplanted into the striata of hemi-Parkinsonian rats; animals were tested for rotational behavior and, after killing, immunohistochemistry was performed.

RESULTS

Following differentiation, cells displayed neuronal morphology and were found to express neural genes and proteins. Furthermore, some of the cells exhibited gene and protein profiles typical of dopaminergic precursors. Finally, transplantation of neural-induced cells into the striatum of hemi-Parkinsonian rats resulted in improvement of their behavioral deficits, as determined by apomorphine-induced rotational behavior. The transplanted induced cells proved to be of superior benefit compared with the transplantation of naive hMSC. Immunohistochemical analysis of grafted brains revealed that abundant induced cells survived the grafts and some displayed dopaminergic traits.

DISCUSSION

Our results demonstrate that induced neural hMSC may serve as a new cell source for the treatment of neurodegenerative diseases and have potential for broad application. These results encourage further developments of the possible use of hMSC in the treatment of Parkinson's disease.

[(123)I]-FP-CIT SPECT and olfaction test in patients with combined postural and rest tremor

Mixed-type tremors pose a clinical diagnostic challenge. The aim of the study was to better characterize patients with combined postural and rest tremor. Patients were categorized into four groups: essential tremor (ET) (n = 7), combined rest + postural tremor (n = 17), PD (n = 17), and control subjects (n = 9). All underwent the University of Pennsylvania Smell Identification Test (UPSIT). The mixed-tremor group was also evaluated with SPECT imaging using the dopamine transporter (DaT) ligand (123)I-labeled FP-CIT. There was no significant difference in olfaction scores between the mixed tremor and essential tremor groups (23.2 +/- 6.6 vs 21.7 +/- 4.9) or between these groups and controls (27.2 +/- 5.0). The patients with PD had significantly lower scores than all the other groups (13.7 +/- 5.4, p < 0.001). Of the 12 patients with mixed tremor evaluated by SPECT, 9 had normal findings. This study suggests that rest tremor is part of the spectrum of ET, even in patients with long-standing disease. However, in a minority of patients, there might be transformation of ET-PD.

Intrastriatal transplantation of mouse bone marrow-derived stem cells improves motor behavior in a mouse model of Parkinson's disease

Strategies of cell therapy for the treatment of Parkinson's disease (PD) are focused on replacing damaged neurons with cells to restore or improve function that is impaired due to cell population damage. In our studies, we used mesenchymal stromal cells (MSCs) from mouse bone marrow. Following our novel neuronal differentiation method, we found that the basic cellular phenotype changed to cells with neural morphology that express specific markers including those characteristic for dopaminergic neurons, such as tyrosine hydroxylase (TH). Intrastriatal transplantation of the differentiated MSCs in 6-hydroxydopamine-lesioned mice led to marked reduction in the amphetamine-induced rotations. Immunohistological analysis of the mice brains four months post transplantation, demonstrated that most of the transplanted cells survived in the striatum and expressed TH. Some of the TH positive cells migrated toward the substantia nigra. In conclusion, transplantation of bone marrow derived stem cells differentiated to dopaminergic-like cells, successfully improved behavior in an animal model of PD suggesting an accessible source of cells that may be used for autotransplantation in patient with PD.

Primary postural instability: a cause of recurrent sudden falls in the elderly

Elderly patients with recurrent falls are frequently diagnosed with an extrapyramidal syndrome. This study aims to characterise a distinct group of patients with recurrent falls and postural instability as a hallmark of the clinical examination. The study took place in the Movement Disorders Unit, Rabin Medical Center, Petah Tiqva, Israel among 26 patients with recurrent falls who had no clinical evidence of a neurodegenerative disease. Medical records, neurological examination and brain imaging studies were assessed. Falls in these patients were sudden, unprovoked, with no vertigo or loss of consciousness. All had postural instability with minimal or no abnormality on the neurological examination. Brain imaging showed diffuse ischaemic changes in 65%. [(123)I]-FPCIT SPECT with the dopamine transporter ligand, performed in five patients, was normal in all. Recurrent falls might be caused by a neurological syndrome that primarily affects balance control. The importance of identifying this disorder is its distinction from other parkinsonian syndromes causing falls.

Autotransplantation of bone marrow-derived stem cells as a therapy for neurodegenerative diseases

Neurodegenerative diseases are characterized by a progressive degeneration of selective neural populations. This selective hallmark pathology and the lack of effective treatment modalities make these diseases appropriate candidates for cell therapy. Bone marrow-derived mesenchymal stem cells (MSCs) are self-renewing precursors that reside in the bone marrow and may further be exploited for autologous transplantation. Autologous transplantation of MSCs entirely circumvents the problem of immune rejection, does not cause the formation of teratomas, and raises very few ethical or political concerns. More than a few studies showed that transplantation of MSCs resulted in clinical improvement. However, the exact mechanisms responsible for the beneficial outcome have yet to be defined. Possible rationalizations include cell replacement, trophic factors delivery, and immunomodulation. Cell replacement theory is based on the idea that replacement of degenerated neural cells with alternative functioning cells induces long-lasting clinical improvement. It is reasoned that the transplanted cells survive, integrate into the endogenous neural network, and lead to functional improvement. Trophic factor delivery presents a more practical short-term approach. According to this approach, MSC effectiveness may be credited to the production of neurotrophic factors that support neuronal cell survival, induce endogenous cell proliferation, and promote nerve fiber regeneration at sites of injury. The third potential mechanism of action is supported by the recent reports claiming that neuroinflammatory mechanisms play an important role in the pathogenesis of neurodegenerative disorders. Thus, inhibiting chronic inflammatory stress might explain the beneficial effects induced by MSC transplantation. Here, we assemble evidence that supports each theory and review the latest studies that have placed MSC transplantation into the spotlight of biomedical research.

Recurrent hemorrhagic shoulder treated with hemiarthroplasty--a case report

Recurrent hemorrhagic shoulder is a rare entity that is scarcely addressed in the literature. We describe a case of recurrent hemorrhagic shoulder and review treatment options for this unusual disorder.

Camptocormia in Parkinson's disease: new insights

Camptocormia—either a central disorder or an outcome of peripheral mechanism

Skin biopsy for assessment of autonomic denervation in Parkinson's disease

Autonomic dysfunction in Parkinson's disease (PD) is considered a late complication of the disease or an adverse effect of anti-parkinsonian medications. Morphological changes are demonstrated only by postmortem examination. The study objective was to evaluate peripheral autonomic neural involvement in PD using punch skin biopsy. The study sample included 22 patients (mean age 50 +/- 7.7 years, mean disease duration 5.3 +/- 3.8 years) and 19 controls. Four-millimeter skin biopsies were immunohistochemically stained with anti-PGP 9.5 antibody. Autonomic innervation of the blood vessels, sweat glands, and erector pili muscles was assessed and rated from 0 (normal) to 2 (severe). Cutaneous autonomic innervation was decreased in patients compared to controls. Semi quantitative analysis demonstrated reduced autonomic innervation of the blood vessels (1.0 +/- 0.8 vs. 0.42 +/- 0.8 in controls; p < 0.02), of sweat glands (0.95 +/- 0.67 vs. 0.47 +/- 0.61; p < 0.02) and of the erector pili muscles (1.06 +/- 0.55 vs 0.21 +/- 0.42; p < 0.001). This method demonstrates that the peripheral autonomic system is affected in PD at early stage of the disease and that autonomic involvement in PD may be more prevalent than previously thought.

Increased survival and migration of engrafted mesenchymal bone marrow stem cells in 6-hydroxydopamine-lesioned rodents

Parkinson's disease is characterized by the loss of dopaminergic neurons in the substantia nigra. Attempted replacement of these neurons by stem cells has proved inconclusive. Bone marrow mesenchymal stem cells (MSC) are multipotent, differentiating into a variety of cells, including neuron-like cells. We used the 6-hydroxydopamine (6-OHDA) animal model of Parkinson's disease to assess migration and differentiation of transplanted MSC. We found in rodents that transplanted MSC survive better in the 6-OHDA-induced damaged hemisphere compared to the unlesioned side. Moreover, contralaterally engrafted MSC migrated through the corpus callosum to populate the striatum, thalamic nuclei and substantia nigra of the 6-OHDA-lesioned hemisphere. In conclusion, we demonstrate that 6-OHDA-induced damage increases the viability of transplanted MSC and attracts these cells from the opposite hemisphere.

Integral therapeutic potential of bone marrow mesenchymal stem cells

Bone marrow derived mesenchymal stem cells (MSC) are adult stem cells that reside within the bone marrow compartment. In the traditional developmental model, adult stem cells are able to differentiate only to the tissue in which they reside. Recent data have challenged the committed fate of the adult stem cells, presenting evidence for their multi-lineage differentiation potential. In addition, potential therapeutic benefits of MSC administration have been the main concern of much research, including clinical trials. These studies promote adult stem cell therapy by shedding some light on the therapeutic potential of MSC and their mechanism of action. Many doubts have found their way into MSC research. They question MSC potency and beneficial contribution. However, these obstacles should not arrest but set a challenge to MSC researchers to examine their achievements under a magnifying glass. Therapeutic benefits of MSC exogenous delivery do not run counter to its possible participation in endogenous repair. Several reports imply MSC involvement in physiological repair but no explicit data support this hypothesis. This review tries to put MSC research into perspective. Possible therapeutic applications of MSC therapy for damaged tissue replacement, tissue engineering and the underlying repair mechanisms will be discussed. In addition, reported data about MSC possible involvement in physiological multiple tissue repair, their homing to injury and site-specific differentiation will be presented.

Rasagiline as an adjunct to levodopa in patients with Parkinson's disease and motor fluctuations (LARGO, Lasting effect in Adjunct therapy with Rasagiline Given Once daily, study): a randomised, double-blind, parallel-group trial

BACKGROUND

Rasagiline mesylate is a novel drug for Parkinson's disease with selective, irreversible monoamine oxidase B (MAO-B) inhibitor activity, and is effective as monotherapy in early disease. This study investigated rasagiline efficacy and safety in levodopa-treated patients with Parkinson's disease and motor fluctuations.

METHODS

In an 18-week, double-blind, multicentre (74 hospitals and academic centres in Israel, Argentina, and Europe) trial, 687 outpatients were randomly assigned to oral rasagiline (231 individuals; 1 mg once daily), entacapone (227; 200 mg with every levodopa dose), or placebo (229). Primary outcome was change in total daily off-time (intention-to-treat population). Other measures included the clinical global improvement (CGI) score and unified Parkinson's disease rating scale (UPDRS) scores. Analysis was by intention to treat.

FINDINGS

88 (13%) patients who were assigned treatment did not complete the study (23 rasagiline, 30 entacapone, 35 placebo), mainly because of withdrawal of consent (n=34) and adverse events (n=34). Both rasagiline and entacapone reduced mean daily off-time (-1.18 h rasagiline and -1.2 h entacapone vs placebo -0.4 h; p=0.0001, p<0.0001, respectively) and increased daily on-time without troublesome dyskinesia (0.85 h vs placebo 0.03 h; p=0.0005 for both). We recorded significant mean improvements in CGI scores (-0.86 rasagiline and -0.72 entacapone vs -0.37 placebo; p<0.0001, p=0.0002, respectively). Changes in UPDRS scores also significantly improved for activities of daily living during off-time (-1.71 and -1.38 vs placebo; p<0.0001, p=0.0006, respectively) and motor function during on-time (-2.94 and -2.73 vs placebo; both p<0.0001). Frequency of adverse events was similar for all treatments.

INTERPRETATION

Once-daily rasagiline reduces mean daily off-time and improves symptoms of Parkinson's disease in levodopa-treated patients with motor fluctuations, an effect similar to that of entacapone.

Quantitative measurement of pain sensation in patients with Parkinson disease

BACKGROUND

Pain is common in patients with Parkinson disease (PD) and can precede the diagnosis of the disease. Experimental studies and clinical evidence indicate involvement of basal ganglia and dopaminergic pathways in central pain processing.

OBJECTIVE

To quantitatively assess and compare pain perception in patients with unilateral PD with and without pain and in patients with response fluctuations.

METHODS

Thirty-six patients with PD (mean age, 61.8 +/- 11.2 years) with predominantly unilateral disease, 15 patients with response fluctuations (mean age, 65.3 +/- 10.4 years), and 28 age-matched healthy control subjects participated in the study. Subjective pain was assessed using the visual analog scale with von Frey filaments for tactile thresholds and contact thermode for warm sensation (WS) and heat pain thresholds (HPTs).

RESULTS

Tactile and WS thresholds did not differ between patients in both patient groups and control subjects nor between sides. HPT was lower in patients with PD who experienced pain (n = 21) compared with those who did not (42.6 +/- 3.0 degrees C vs 45.6 +/- 2.8 degrees C; p < 0.01) and those who experienced pain in the more affected side (41.4 +/- 2.6 degrees C vs 43.7 +/- 3.3 degrees C; p < 0.0001). In patients with fluctuations there were no side differences in WS and HPT or between "on" and "off" periods.

CONCLUSION

Endogenous pain in patients with Parkinson disease is accompanied by increased sensitivity to some painful stimuli, suggesting that basal ganglia abnormality also involves pain encoding.

Polymorphism in candidate genes: implications for the risk and treatment of idiopathic Parkinson's disease

Idiopathic Parkinson's disease (IPD) is a progressive neurodegenerative disorder for which no restorative or neuroprotective therapy is available. Interest has recently been directed to association studies on polymorphisms of various genes, mainly those related to dopamine metabolism and transport, and their effect on response to PD, which includes primarily levodopa and dopaminomimetics. Approximately 15-20% of patients with PD do not respond to levodopa, and the majority of those who do respond develop adverse fluctuations in motor response, primarily levodopa-induced dyskinesias. This review summarizes the influence of polymorphisms in various genes on the relative risk of IPD and on levodopa efficacy. It focuses on the importance of well-designed polymorphism studies that include large samples of patients with IPD and tightly matched controls and use identical methodologies. Valid data on such polymorphisms might increase the efficacy of levodopa, decrease its side effects, and reduce the occurrence of levodopa-induced dyskinesias. They might also provide a novel diagnostic tool for PD.

Molecular biology of dopamine-induced apoptosis : possible implications for Parkinson's disease

The causes for the highly selective loss of dopaminergic neurons in the substantia nigra pars compacta in Parkinson's disease (PD) are still unknown. However, a major advance has been recently made with the introduction of the concept of apoptosis as the route leading this specific neuronal population to degeneration. Apoptosis, or programmed cell death (PCD), is an active, controlled program inherent in every living cell. Upon receiving certain signals, cells that are destined to die undergo a highly characteristic process of "suicide." This process consists of massive biochemical and morphological alterations, including cell shrinkage, loss of cell-to-cell contacts, blebbing of cell membranes, cytoskeletal rearrangements, and DNA condensation and fragmentation. It culminates in cell conversion to membrane-bound particles (apoptotic bodies) that are ready to be digested by neighboring macrophages (1-3).

[Non-freezing cold injury in soldiers]

Non-freezing cold injury (NFCI) is an injury of the hands or feet resulting from exposure to wet conditions and temperatures just above freezing, typically found in soldiers. NFCI is due to microvascular endothelial damage, stasis and vascular occlusion. At first, the tissue is cold and anesthetic, progressing to hyperemia in 24-48 hours. Hyperemia is accompanied by an intense painful burning sensation as well as blisters, redness, and possibly, ulcerations. NFCI management raises frustration in both medical officers and commanders. Most authorities are not aware of or remain unimpressed with the severity of NFCI, nor do they realize that it produces lifelong symptomatology. The following review of the available literature attempts to clear up some issues regarding the definition, pathogenesis, symptoms and preventative measures available in NFCI, including our own experience.

Brain injury-related heterotopic bone formation: treatment strategy and results

OBJECTIVES

Heterotopic bone formation (HO) is a phenomenon occurring in some neurologically injured patients that can adversely affect their rehabilitation. The current study aimed at evaluating functional results and recurrence rates after recurrence of such lesions.

DESIGN

The results of 12 excisions of HO in 9 patients were assessed. A single-dose of 750 cGy delivered 24 hr postoperatively was used in seven of nine patients.

RESULTS

One year postintervention, the arc of motion averaged 92.5 degrees in the hips, 66.6 in the knees, and 60 degrees in the elbow. Despite increased uptake on bone scans in all patients, recurrence did not occur in any patient. Ambulation levels improved in four of eight hips. Ease of personal hygiene was improved in all patients, although some patients still require assistance.

CONCLUSIONS

Excision of symptomatic HO is recommended if limitation of joint motion seems to hinder the patient's rehabilitation. Some motor control is desirable to achieve significant improvement in the patient's quality of life. Increased uptake on bone scans is not a contraindication to surgical excision of HO, provided the neurologic status is stabilized.

The role of glutamatergic transmission in the pathogenesis of levodopa-induced dyskinesias. Potential therapeutic approaches

Dyskinesias are the most frequent adverse effect of chronic levodopa therapy in patients with Parkinson's disease (PD). Current pharmacological treatment for this problem is unsatisfactory. Recently, there is evidence for the role of glutamate in the basal ganglia neuronal circuitry in the generation of dyskinesias. If indeed glutamatergic overactivity beyond the dopaminergic synapses plays a role in the pathogenesis of these involuntary movements, there is hope that its suppression may be beneficial without causing loss of levodopa efficacy and parkinsonian deterioration. Indeed, NMDA receptor antagonists such as amantadine and dextrometorphan can reduce such dyskinesias. We tested the efficacy of riluzole, an inhibitor of glutamatergic transmission in the inhibition of levodopa-induced dyskinesias.

The effect of deprenyl washout in patients with long-standing Parkinson's disease

Deprenyl, an irreversible MAO-B inhibitor, is known to have a symptomatic effect in de novo patients with Parkinson's disease (PD). It has, however, not been studied thoroughly in patients with advanced PD and response fluctuations. This study evaluated the effect of washout of deprenyl in patients with long-standing PD. Eleven PD patients who were on chronic treatment with deprenyl (mean age 57 +/- 8 years, mean disease duration 8.4 +/- 2.9 years), seven with response fluctuations, were enrolled in a double-blind study of a novel MAO-B inhibitor. A deprenyl washout period of one month was required prior to initiation of treatment with the trial drug. Patients were evaluated by Unified Parkinson's Disease Rating scale (UPDRS) before and one month after the washout period. Motor function was quantified by computerized tapping speed and movement time test. Results showed that neither total UPDRS scores (22 +/- 16 vs. 18 +/- 16, respectively) nor tapping speed and movement time changed significantly (4.4 +/- 0.5 vs. 4.2 +/- 0.3 Hz and 159 +/- 45 vs. 161 +/- 40 seconds; p > 0.1, respectively). However, eight patients reported various degrees of subjective deterioration, among them were the seven fluctuating patients. Two patients first began to experience response fluctuations during the washout period. It seems that deprenyl has a symptomatic effect, especially in patients with response fluctuations, and it may postpone the appearance of fluctuations in patients with PD. Attempts to discontinue treatment with deprenyl may aggravate disease symptoms.

Protective effect of insulin-like-growth-factor-1 against dopamine-induced neurotoxicity in human and rodent neuronal cultures: possible implications for Parkinson's disease

Parkinson's disease (PD) is characterized by a progressive loss of 70-80% of dopaminergic (DA) neurons in the substantia nigra. High concentrations of DA were suggested to induce oxidative stress and selective neurodegeneration. We evaluated the effect of insulin-like-growth-factor-1 (IGF-1) on DA toxicity in neuronal cultures. IGF-1 (0.5 microg/ml) suppressed cell death induced by exposure to DA (0.3 mM) after 2 and 4 days, in a rat cerebellar culture. Similarly, IGF-1 (0.5 and 1.0 microg/ml) antagonized DA (0.125 and 0.250 mM) neurotoxicity in a human neuroblastoma cell line (SK-N-SH). Flowcytometric analysis of neuroblastoma cells treated with DA (0.5 mM) showed increased apoptosis, which was significantly reduced by IGF-1. The effect of IGF-1 was associated with increased Bcl-2 expression as indicated by flowcytometry and Western blot analysis. We suggest that IGF-1 possesses a neuroprotective effect against DA-induced toxicity, and may have a potential role in the treatment of PD.

6-Hydroxydopamine increases ubiquitin-conjugates and protein degradation: implications for the pathogenesis of Parkinson's disease

One of the hallmarks of Parkinson's disease (PD) is pathological structure, termed Lewy body, containing inclusions of ubiquitinated proteins in the dopaminergic neurons in the substantia nigra. The mechanism leading to the formation of these aggregates is unclear, although it has been shown that mutations in alpha-synuclein or in the ubiquitin-related enzyme UCH-L1 might induce such protein aggregation. We, therefore, examined the possible role of 6-hydroxydopamine (6-OHDA), a dopaminergic neurotoxin used in PD experimental models, in causing protein degradation and its association with the ubiquitin system. Using antiubiquitin antibodies we found that exposure of SH-SY5Y neuroblastoma and PC-12 cell lines to 6-OHDA increased the levels of free ubiquitin and ubiquitin-conjugated proteins, in a dose-dependent manner. Furthermore, metabolic labeling with 35S-methionine, demonstrated that 6-OHDA markedly increased protein degradation, as indicated by the secretion of protein metabolites to the medium. Inhibition of the proteasome activity by the specific inhibitor MG132, attenuated the protein degradation induced by 6-OHDA and potentiated its toxicity. Administration of the antioxidant N-acetylcysteine to the 6-OHDA-treated cells, increased cell survival and reduced protein degradation. In conclusion, our findings suggest that 6-OHDA toxicity is associated with protein degradation and ubiquitin-proteasome system activation.

Abnormal skin wrinkling in the less affected side in hemiparkinsonism-a possible test for sympathetic dysfunction in Parkinson's disease

Some patients with Parkinson's disease (PD) suffer from autonomic dysfunction, even in the early stage of the disease. We examined the skin wrinkling response following immersion of the hands in warm water in 18 patients with hemiparkinsonism. This test evaluates the function of the sympathetic autonomic system. Mean age of the patients was 61 +/- 10 and mean disease duration 5.5 +/- 3.5 years. Both hands of each patient were immersed in warm water for 30 minutes and the number of skin ridges of the fingertip of each finger was counted. The results of each hand were compared to those of nine healthy controls. The mean number of the ridges of the less affected hand was significantly decreased as compared to the affected hand and controls (6.1 +/- 6.8 vs 13.1 +/- 6.8 and 15.3 +/- 8.5, respectively; P < 0.01). These results suggest that autonomic dysfunction is prevalent in the less affected side of patients with PD and can be simply tested by the skin response test.

Spinal dural arteriovenous fistulae--a diagnostic challenge

BACKGROUND

Spinal dural arteriovenous fistulae comprise the majority of spinal vascular malformations. The most common clinical presentation is that of progressive myeloradiculopathy, probably related to venous hypertension, which may lead to permanent disability and even death.

OBJECTIVE

To report our clinical experience with spinal dural arteriovenous fistulae.

METHODS

Nine patients with spinal dural AVF were managed at our center during a one year period (1998-1999). The patients, eight men and one woman ranging in age from 46 to 75 years, presented with initially fluctuating and eventually permanent and progressive paraparesis, sensory disturbances and sphincter dysfunction. The neurological signs generally began symmetrically and progressed from the distal to proximal limb regions. The duration of symptoms before diagnosis ranged from 6 to 36 months during which the patients underwent an extensive but fruitless work-up and even unnecessary operations due to misdiagnosis. All patients finally underwent magnetic resonance imaging and spinal angiography, which demonstrated the pathological vascular fistula. Interruption of the AVF was achieved by embolization or by surgical resection.

RESULTS

Following treatment, six patients experienced improvement of gait and sphincter control, and the severe neurological deficits stabilized in the other three patients with long duration of illness. There was no further deterioration in any of the treated patients.

CONCLUSIONS

The history, neurological findings and radiological changes on MRI scan should alert clinicians to the possibility of spinal dural AVF, leading to diagnostic spinal angiography. Early diagnosis and treatment may significantly improve outcome and prevent permanent disability and even mortality.

Glutaredoxin protects cerebellar granule neurons from dopamine-induced apoptosis by dual activation of the ras-phosphoinositide 3-kinase and jun n-terminal kinase pathways

Glutaredoxin 2 (Grx2) from Escherichia coli protects cerebellar neurons from dopamine-induced apoptosis via nuclear factor kappa B (NF-kappaB) activation, which is mediated by the expression of redox factor-1 (Ref-1). An analysis of the mechanisms underlying Grx2 protective activity revealed dual activation of signal transduction pathways. Grx2 significantly activated the Ras/phosphoinositide 3-kinase/Akt/NF-kappaB cascade in parallel to the Jun N-terminal kinase (JNK)/AP1 cascade. Dopamine, in comparison, down-regulated both pathways. Treatment of neurons with Ref-1 antisense oligonucleotide reduced the ability of Grx2 to activate Akt and AP-1 but had no effect on the phosphorylation of JNK1/2, suggesting that Akt/NF-kappaB and AP-1 are regulated by Ref-1. Exposure of the neurons to JNK1/2 antisense oligonucleotide in the presence of Grx2 significantly reduced AP-1 and NF-kappaB DNA binding activities and abolished Grx2 protection. These results demonstrate that dual activation of Ras/phosphoinositide 3-kinase and AP-1 cascades, which are mediated by Ref-1, is an essential component of the Grx2 mechanism of action.

Heredity in Parkinson's disease: new findings

Multiple factors have been hypothesized over the last century to be causative or contributory for Parkinson's disease. Hereditary factors have recently emerged as a major focus of Parkinson's disease research. Until recently most of the research on the etiology of Parkinson's disease concentrated on environmental factors, and the possibility that genetic factors contribute significantly to the pathogenesis of Parkinson's disease has been neglected. However, it has become increasingly apparent that even in sporadic cases, the disease most likely reflects a combination of genetic susceptibility and an unknown environmental insult. Moreover, the identification of genes and proteins that may cause hereditary parkinsonism substantially contributes to our ability to understand the pathogenesis of Parkinson's disease and may help in the early identification of the disease and its treatment. The discovery of alpha-synuclein mutations in families with autosomal dominant Parkinson's disease sheds light on its role in sporadic Parkinson's disease. It seems that this protein tends to aggregate when the cellular milieu is altered [14-16]. The question as to the exact changes that cause its deposition remains open. One of the major possibilities is oxidative stress [16]. The role of these aggregates in neuronal cell death is also still unclear. Transgenic mice expressing wild-type human alpha-synuclein developed progressive accumulation of alpha-synuclein and ubiquitin-immunoreactive inclusions in neurons in the neocortex, hippocampus and the substantia nigra. These alterations were associated with loss of dopaminergic terminals and motor impairments [24]. This finding suggests that accumulation of alpha-synuclein may play a causal role in sporadic Parkinson's disease as well. The parkin protein seems to be a crucial survival factor for nigral neurons [15]. The parkin protein is related to the ubiquitin pathway, which is important in the elimination of damaged proteins. Ubiquitin-mediated degradation of proteins plays a central role in the control of numerous processes, including signal transduction, receptor and transcriptional regulations, programmed cell death, and breakdown of abnormal proteins that may interfere with normal cell functions. Further studies on the function of Parkin protein and its relation to the ubiquitin pathway could elucidate at least one of the molecular mechanisms of nigral neuronal death. A mutation in the ubiquitin carboxy-teminal hydrolase L1 gene also implies the importance of the ubiquitin pathway in Parkinson's disease. Abnormal tau protein was found to be the cause of familial frontotemporal dementia and parkinsonism. It tends to form filamentous structures, which may lead to neuronal death. Elucidation of the molecular mechanism of neuronal death in this disease may contribute to our understanding of sporadic diseases with tau accumulation, such as corticobasal degeneration, progressive supranuclear palsy, Pick's disease, Alzheimer's disease and possibly also the pathogenesis of Parkinson's disease. Other genetic loci have been identified by linkage analysis of patients with familial parkinsonism. These loci conceal other genes and proteins that may be pivotal factors in the pathogenesis of Parkinson's disease. The discovery of genetic mutations in patients with parkinsonism may offer us new insights into the understanding of the pathways leading to neuronal death and development of Parkinson's disease. It may also help in the early identification of susceptible people to this disease and possibly in developing new treatment strategies.

Is there a rationale for neuroprotection against dopamine toxicity in Parkinson's disease?

Parkinson's disease is a progressive neurological disease caused by rather selective degeneration of the dopaminergic neurons in the substantia nigra. Though subject to intensive research, the etiology of this nigral loss is still undetermined and treatment is basically symptomatic. The current major hypothesis is that nigral neuronal death in PD is due to excessive oxidative stress generated by auto and enzymatic oxidation of the endogenous neurotransmitter dopamine (DA), the formation of neuromelanin (NM) and the presence of a high concentration of iron. In this review article although we concisely describe the effects of NM and iron on neuronal survival, we mainly focus on the molecular mechanisms of DA-induced apoptosis. DA exerts its toxic effects through its oxidative metabolites either in vitro or in vivo The oxidative metabolites then activate a very intricate web of signals, which culminate in cell death. The signal transduction pathways and genes, which are associated with DA toxicity are described in detail.

Oxidative stress induced-neurodegenerative diseases: the need for antioxidants that penetrate the blood brain barrier

Oxidative stress (OS) has been implicated in the pathophysiology of many neurological, particularly neurodegenerative diseases. OS can cause cellular damage and subsequent cell death because the reactive oxygen species (ROS) oxidize vital cellular components such as lipids, proteins, and DNA. Moreover, the brain is exposed throughout life to excitatory amino acids (such as glutamate), whose metabolism produces ROS, thereby promoting excitotoxicity. Antioxidant defense mechanisms include removal of O(2), scavenging of reactive oxygen/nitrogen species or their precursors, inhibition of ROS formation, binding of metal ions needed for the catalysis of ROS generation and up-regulation of endogenous antioxidant defenses. However, since our endogenous antioxidant defenses are not always completely effective, and since exposure to damaging environmental factors is increasing, it seems reasonable to propose that exogenous antioxidants could be very effective in diminishing the cumulative effects of oxidative damage. Antioxidants of widely varying chemical structures have been investigated as potential therapeutic agents. However, the therapeutic use of most of these compounds is limited since they do not cross the blood brain barrier (BBB). Although a few of them have shown limited efficiency in animal models or in small clinical studies, none of the currently available antioxidants have proven efficacious in a large-scale controlled study. Therefore, any novel antioxidant molecules designed as potential neuroprotective treatment in acute or chronic neurological disorders should have the mandatory prerequisite that they can cross the BBB after systemic administration.

Haloperidol-induced neurotoxicity--possible implications for tardive dyskinesia

Tardive dyskinesia (TD) is one of the major side effects of long term neuroleptic treatment. The pathophysiology of this disabling and commonly irreversible movement disorder is still obscure. The traditional concept of supersensitivity of striatal dopamine receptors as the mechanism involved in the development of TD is not satisfying, and current studies have focused on the role of neuroleptic-induced neuronal toxicity in the development of TD. We performed a series of experiments to gain a better understanding on the mechanisms involved in induction of TD. We have evaluated the direct neurotoxic effect of haloperidol (HP), a widely--used neuroleptic drug, and its three metabolites, in mouse neuronal cultures and in PC-12 cells. We found that the features of HP-induced cell death were apoptotic rather than necrotic, as indicated by different DNA-staining methods and specific caspases inhibitors. Moreover, cotreatment with antioxidants such as vitamin E and N-acetylcysteine (NAC) significantly protected the cultures. Further studies on the mechanisms underlying HP-induced toxicity may lead to the development of new neuroprotective therapeutic strategies.

New therapies for Parkinson's disease

In the last decade there has been a surge of new therapeutic strategies for the treatment of Parkinson's disease along with a change of concepts about how the disease should be treated. The gold standard remains levodopa preparations, which have a rapid and dramatic symptomatic effect by replenishing the reduced dopamine levels in caudate and putamen nuclei. However, keeping in mind the complications that may emerge following long-term treatment, its initiation should possibly be delayed to the more advanced stages of the illness, especially in younger patients, in favour of dopamine agonists monotherapy. The adverse reactions that become prominent and disabling in late stages of the disease, i. e., dyskinesias, response fluctuations, and psychiatric side effects, can currently be managed by novel pharmacological as well as surgical strategies. Future therapies will focus on transplantation of dopaminergic embryonic tissue, gene therapy, and neuroprotective treatments.

The molecular mechanism of dopamine-induced apoptosis: identification and characterization of genes that mediate dopamine toxicity

Parkinson's disease (PD) is a progressive neurological disorder caused by rather selective degeneration of the dopaminergic (DA) neurons in the substantia nigra. Though subject to intensive research, the etiology of this nigral neuronal loss is still enigmatic and treatment is basically symptomatic. The current major hypothesis suggests that nigral neuronal death in PD is due to excessive oxidative stress generated by auto- and enzymatic oxidation of the endogenous neurotransmitter dopamine (DA), the formation of neuromelanin and presence of high concentrations of iron. We have found that DA toxicity is mediated through its oxidative metabolites. Whereas thiol-containing antioxidants provided marked protection against DA toxicity, ascorbic acid accelerated DA-induced death. Using the differential display approach, we sought to isolate and characterize genes whose expression is altered in response to DA toxicity. We found an upregulation of the collapsin response mediator protein (CRM) and TCP-1delta in sympathetic neurons, which undergo dopamine-induced apoptosis. The isolation of these genes led us to examine the expression and activity of CRM and TCP-1delta related genes. Indeed, we found a significant induction of mRNAs of the secreted collapsin-1 and the mitochondrial stress protein HSP60. Antibodies directed against collapsin-1 provided marked and prolonged protection of several neuronal cell types from dopamine-induced apoptosis. In a parallel study, using antisense technology, we found that inhibition of TCP-1delta expression significantly reduced DA-induced neuronal death. These findings suggest a functional role for collapsin-1 and TCP-1delta as positive mediators of DA-induced neuronal apoptosis.

Activation of nuclear transcription factor kappa B (NF-kappaB) is essential for dopamine-induced apoptosis in PC12 cells

The etiology of Parkinson's disease is still unknown, though current investigations support the notion of the pivotal involvement of oxidative stress in the process of neurodegeneration in the substantia nigra (SN). In the present study, we investigated the molecular mechanisms underlying cellular response to a challenge by dopamine, one of the local oxidative stressors in the SN. Based on studies showing that nuclear factor kappa B (NF-kappaB) is activated by oxidative stress, we studied the involvement of NF-kappaB in the toxicity of PC12 cells following dopamine exposure. We found that dopamine (0.1-0.5 m M) treatment increased the phosphorylation of the IkappaB protein, the inhibitory subunit of NF-kappaB in the cytoplasm. Immunoblot analysis demonstrated the presence of NF-kappaB-p65 protein in the nuclear fraction and its disappearance from the cytoplasmic fraction after 2 h of dopamine exposure. Dopamine-induced NF-kappaB activation was also evidenced by electromobility shift assay using radioactive labeled NF-kappaB consensus DNA sequence. Cell-permeable NF-kappaB inhibitor SN-50 rescued the cells from dopamine-induced apoptosis and showed the importance of NF-kappaB activation to the induction of apoptosis. Furthermore, flow cytometry assay demonstrated a higher level of translocated NF-kappaB-p65 in the apoptotic nuclei than in the unaffected nuclei. In conclusion, our findings suggest that NF-kappaB activation is essential to dopamine-induced apoptosis in PC12 cells and it may be involved in nigral neurodegeneration in patients with Parkinson's disease.

Apoptosis as a general cell death pathway in neurodegenerative diseases

Neurodegenerative processes are generally characterized by the long-lasting course of neuronal death and the selectivity of the neuronal population or brain structure involved in the lesion. Two main common forms of cell death that have been described in neurons as in other vertebrate tissues i.e., necrosis and apoptosis. Necrosis is the result of cellular "accidents", such as those occurring in tissues subjected to chemical trauma. The necrotizing cells swell, rupture and provoke an inflammatory response. Apoptosis, on the other hand, is dependent on the cell's "decision" to commit suicide and die, and therefore is referred to as "programmed cell death" (PCD). The course of apoptotic death is characterized by a massive morphological change, including cell shrinkage, nuclear (chromosome) condensation and DNA degradation. Activation of PCD in an individual cell is based on its own internal metabolism, environment, developmental background and its genetic information. Such a situation occurs in most of the neurodegenerative disorders such as Alzheimer's, Parkinson's and Huntington's diseases and amyotrophic lateral sclerosis (ALS). In these pathological situations, specific neurons undergo apoptotic cell death characterized by DNA fragmentation, increased levels of pro-apoptotic genes and "apoptotic proteins" both, in human brain and in experimental models. It is of utmost importance to conclusively determine the mode of cell death in neurodegenerative diseases, because new "anti-apoptotic" compounds may offer a means of protecting neurons from cell death and of slowing the rate of cell degeneration and illness progression.

Consensus statement on the role of acute dopaminergic challenge in Parkinson's disease

Available evidence on the practice of acute pharmacological challenge tests in parkinsonian patients was reviewed by a committee of experts, which achieved a general consensus. The published data deal mainly with the acute administration of levodopa and apomorphine in Parkinson's disease. Such challenge may serve different purposes, e.g., research, diagnosis, or tailoring of treatment. Unique protocols describing the clinical setting and practice parameters are not available. The present paper describes the scientific background and supplies practical guidelines, whenever possible, to perform and evaluate acute challenge tests in parkinsonian syndromes. With the appropriate indication and setting, acute challenge tests are useful in diagnosis and therapy of Parkinson's disease and related disorders.

The pharmacokinetic profile of the "first ever" oral dose of levodopa in de novo patients with Parkinson's disease

To understand the delay in the clinical benefit that commonly occurs after initiation of levodopa (L-Dopa) treatment, we examined the pharmacokinetic profile of L-Dopa after the first oral dose ever taken of L-Dopa/carbidopa in untreated patients with Parkinson's disease and followed these parameters after 1 month of treatment. This was performed in correlation with the clinical therapeutic effect. Plasma levels of L-Dopa were measured with use of high-performance liquid chromatography with electrochemical detection after administration of the "first ever" 125 mg L-Dopa/12.5 mg carbidopa tablet in 15 patients with de novo Parkinson's disease (mean age, 69 +/- 11 y, mean disease duration, 1.5 +/- 0.8 years). Blood samples were drawn before administration and thereafter at various intervals for a period of 4 hours. Repeated measurements after the same oral dose were performed after 1 month of continued therapy with L-Dopa/carbidopa 125/12.5 mg three times daily. Patients were clinically evaluated by unified Parkinson's disease rating scale motor scores. There was a modest clinical improvement after 1 month of continuous L-Dopa treatment (motor scores, 13.1 +/- 11.6 vs. 17.6 +/- 11.7; p < 0.01). Peak plasma L-Dopa levels and area under the curve did not differ significantly between the first-ever dose and after 1 month of continuous treatment (0.9 +/- 0.1 vs. 1.0 +/- 0.1 microg/mL and 66.0 +/- 30.9 vs. 86.2 +/- 34.9 microg/mL, respectively; p < 0.1. There was also no change in time to peak levels between measurements. Results indicate that the first-ever dose of oral L-Dopa is well absorbed and that pharmacokinetic mechanisms such as reduced absorption of L-Dopa probably do not play a major role in the initial delay in clinical response to oral L-Dopa/carbidopa in patients with Parkinson's disease. The latter phenomena may be linked to central pharmacodynamic mechanisms.