TDP2 protects transcription from abortive topoisomerase activity and is required for normal neural function

Topoisomerase II (TOP2) removes torsional stress from DNA and facilitates gene transcription by introducing transient DNA double-strand breaks (DSBs). Such DSBs are normally rejoined by TOP2 but on occasion can become abortive and remain unsealed. Here we identify homozygous mutations in the TDP2 gene encoding tyrosyl DNA phosphodiesterase-2, an enzyme that repairs 'abortive' TOP2-induced DSBs, in individuals with intellectual disability, seizures and ataxia. We show that cells from affected individuals are hypersensitive to TOP2-induced DSBs and that loss of TDP2 inhibits TOP2-dependent gene transcription in cultured human cells and in mouse post-mitotic neurons following abortive TOP2 activity. Notably, TDP2 is also required for normal levels of many gene transcripts in developing mouse brain, including numerous gene transcripts associated with neurological function and/or disease, and for normal interneuron density in mouse cerebellum. Collectively, these data implicate chromosome breakage by TOP2 as an endogenous threat to gene transcription and to normal neuronal development and maintenance.

Parkin disease: a clinicopathologic entity?

IMPORTANCE

Mutations in the gene encoding parkin (PARK2) are the most common cause of autosomal recessive juvenile-onset and young-onset parkinsonism. The few available detailed neuropathologic reports suggest that homozygous and compound heterozygous parkin mutations are characterized by severe substantia nigra pars compacta neuronal loss.

OBJECTIVE

To investigate whether parkin-linked parkinsonism is a different clinicopathologic entity to Parkinson disease (PD).

DESIGN, SETTING, AND PARTICIPANTS

We describe the clinical, genetic, and neuropathologic findings of 5 unrelated cases of parkin disease and compare them with 5 pathologically confirmed PD cases and 4 control subjects. The PD control cases and normal control subjects were matched first for age at death then disease duration (PD only) for comparison.

RESULTS

Presenting signs in the parkin disease cases were hand or leg tremor often combined with dystonia. Mean age at onset was 34 years; all cases were compound heterozygous for mutations of parkin. Freezing of gait, postural deformity, and motor fluctuations were common late features. No patients had any evidence of cognitive impairment or dementia. Neuronal counts in the substantia nigra pars compacta revealed that neuronal loss in the parkin cases was as severe as that seen in PD, but relative preservation of the dorsal tier was seen in comparison with PD (P = .04). Mild neuronal loss was identified in the locus coeruleus and dorsal motor nucleus of the vagus, but not in the nucleus basalis of Meynert, raphe nucleus, or other brain regions. Sparse Lewy bodies were identified in 2 cases (brainstem and cortex).

CONCLUSIONS AND RELEVANCE

These findings support the notion that parkin disease is characterized by a more restricted morphologic abnormality than is found in PD, with predominantly ventral nigral degeneration and absent or rare Lewy bodies.

Expression of N-methyl-D-aspartate receptor subunit mRNAs in the human brain: hippocampus and cortex

N-methyl-D-aspartate receptor (NR) activation in the hippocampus and neocortex plays a central role in memory and cognitive function. We analyzed the cellular expression of the five NR subunit (NR1 and NR2A-D) mRNAs in these regions with in situ hybridization and human ribonucleotide probes. Film autoradiograms demonstrated a distinct pattern of hybridization signal in the hippocampal complex and the neocortex with probes for NR1, NR2A, and NR2B mRNA. NR2C and NR2D probes yielded scattered signals without a distinct organization. At the emulsion level, the NR1 probe produced high-density hybridization signals across the hippocampal complex. NR2A mRNA was higher in dentate granule cells and pyramidal cells in CA1 and subiculum compared to hilus neurons. NR2B mRNA expression was moderate throughout, with higher expression in dentate granule cells, CA1 and CA3 pyramidal cells than in hilus neurons. In the hippocampal complex, the NR2C probe signal was not different from background in any region, whereas the NR2D probe signal resulted in low to moderate grain densities. We analyzed NR subunit mRNA expression in the prefrontal, parietal, primary visual, and motor cortices. All areas displayed strong NR1 hybridization signals. NR2A and NR2B mRNAs were expressed in cortical areas and layers. NR2C mRNA was expressed at low levels in distinct layers that differed by region and the NR2D signal was equally moderate throughout all regions. Pyramidal cells in both hippocampus and neocortex express NR1, NR2A, NR2B, and, to a lesser extent, NR2D mRNA. Interneurons or granular layer neurons and some glial cells express NR2C mRNA.

Dopaminergic-induced dyskinesia assessment based on a single belt-worn accelerometer

BACKGROUND

After several years of treatment, patients with Parkinson's disease (PD) tend to have, as a side effect of the medication, dyskinesias. Close monitoring may benefit patients by enabling doctors to tailor a personalised medication regimen. Moreover, dyskinesia monitoring can help neurologists make more informed decisions in patient's care.

OBJECTIVE

To design and validate an algorithm able to be embedded into a system that PD patients could wear during their activities of daily living with the purpose of registering the occurrence of dyskinesia in real conditions.

MATERIALS AND METHODS

Data from an accelerometer positioned in the waist are collected at the patient's home and are annotated by experienced clinicians. Data collection is divided into two parts: a main database gathered from 92 patients used to partially train and to evaluate the algorithms based on a leave-one-out approach and, on the other hand, a second database from 10 patients which have been used to also train a part of the detection algorithm.

RESULTS

Results show that, depending on the severity and location of dyskinesia, specificities and sensitivities higher than 90% are achieved using a leave-one-out methodology. Although mild dyskinesias presented on the limbs are detected with 95% specificity and 39% sensitivity, the most important types of dyskinesia (any strong dyskinesia and trunk mild dyskinesia) are assessed with 95% specificity and 93% sensitivity.

CONCLUSION

The presented algorithmic method and wearable device have been successfully validated in monitoring the occurrence of strong dyskinesias and mild trunk dyskinesias during activities of daily living.

Stereotactic pallidotomy performed without using microelectrode guidance in patients with Parkinson's disease: surgical technique and 2-year results

OBJECT

Pallidotomy for the treatment of medically refractory Parkinson's disease (PD) has enjoyed renewed popularity. However, the optimal surgical technique, lesion location, and long-term effectiveness of pallidotomy remain subjects of debate. In this article the authors describe their surgical technique for performing pallidotomy without using microelectrode guidance, and the clinical and radiological results of this procedure.

METHODS

Patients were evaluated preoperatively by using a battery of validated clinical rating scales and magnetic resonance (MR) imaging of the brain. Individuals with severe treatment-refractory idiopathic PD who were believed to be good candidates for surgery underwent computerized tomography scanning- and MR imaging-guided stereotactic pallidotomy. Intraoperative macrostimulation was used to optimize lesion placement and to avoid injury to nearby structures. Lesion location and size were calculated from MR imaging sequences of the brain obtained within the first 24 hours after surgery and again 3 months later. Clinical examinations were conducted at 1.5, 3, 6, 12, and 24 months after surgery. Seventy-five patients (mean age 61 years, range 38-79 years) underwent unilateral pallidotomy. Significant improvements were observed in the "off' period scores for the activities of daily living portion of the Unified Parkinson's Disease Rating Scale (UPDRS), the UPDRS motor scores, total "on" time, levodopa-induced dyskinesias, and contralateral tremor. These improvements were maintained 24 months postoperatively. The mean lesion volume measured on the immediate postoperative MR image was 73 +/- 5.4 mm3. Radiological analysis suggests that initial lesion volume does not predict outcome. The only permanent major complication was a single visual field defect.

CONCLUSIONS

Pallidotomy performed without using microelectrode guidance is a safe and effective treatment for selected patients with medically refractory PD.

Outcomes following staged bilateral pallidotomy in advanced Parkinson's disease

The authors assessed clinical outcome for up to one year after staged bilateral pallidotomy in 14 patients with advanced PD. One year after surgery, dyskinesias were virtually abolished and there were significant reductions in "off" time (67%) and activities of daily living "off" scores (24%), as well as nonsignificant reduction in "off" motor score (39%); "on" scores were unchanged. One patient developed a visual field deficit; two had transient confusion. Staged bilateral pallidotomy improves motor function in selected patients with advanced PD.

Regional dopamine transporter gene expression in the substantia nigra from control and Parkinson's disease brains

OBJECTIVE

To test the hypothesis that differential regional dopamine transporter (DAT) gene expression may underlie the selective vulnerability of certain nigral dopaminergic neurons in Parkinson's disease, DAT mRNA expression was examined in neuronal subpopulations of human postmortem ventral mesencephalon from patients with Parkinson's disease and controls.

METHODS

Radioactive in situ hybridisation histochemistry using a polymerase chain reaction derived ribonucleotide probe for DAT was performed on sections of ventral mesencephalon from the brains of five donors with no history of neurological illness and from five patients with pathologically established Parkinson's disease. The number of silver grains overlying melanised neurons from the paranigral nucleus, dorsal and ventral tier, and pars lateralis of the substantia nigra pars compacta were compared with each other and to background labelling by using a one way factorial analysis of variance (ANOVA) with a significance level of 5%.

RESULTS

In control brains, there was intense DAT mRNA expression in the ventral midbrain with no significant difference in mRNA concentrations among the four regions studied. In the Parkinson's disease brains, there was an overall decrease in the intensity of DAT mRNA expression in the surviving dopaminergic neurons. There were no significant differences in signal between regions in either the control or parkinsonian brains.

CONCLUSION

Taken together, these findings do not support the hypothesis that differential regional DAT gene expression underlies the selective vulnerability of certain nigral dopaminergic neurons in Parkinson's disease, as the vulnerable neurons of the substantia nigra pars compacta do not express more DAT mRNA than the resistant paranigral neurons.

Maternal brain death: medical, ethical and legal issues

CASE PRESENTATION

We present the case of a pregnant woman who experienced a cerebral venous sinus thrombosis resulting in brain death at 13 weeks gestation. We discuss the management of the mother and foetus following this tragic event. We also discuss the complex medical, legal and ethical issues that arose following maternal brain death. The central question is whether continuing maternal organ supportive measures in an attempt to prolong gestation to attain foetal viability is appropriate, or whether it constitutes futile care.

DISCUSSION

Successful maintenance of maternal brain somatic function to facilitate foetal maturation in utero has been reported. While the gestational age of the foetus is central to resolving this issue, there is no clear upper physiological limit to the prolongation of somatic function following brain death. Furthermore, medical experience regarding prolonged somatic support is limited. Finally, the legal rights conferred on the foetus may vary significantly depending on the jurisdiction in which the maternal brain death occurs and may have important implications.

CONCLUSIONS

A consensus building approach, involving the family, is essential to resolving these potentially conflicting issues.

Radiological remission and recovery of thirst appreciation after infliximab therapy in adipsic diabetes insipidus secondary to neurosarcoidosis

BACKGROUND

Neurosarcoidosis is a rare and aggressive variant of systemic sarcoidosis which may result in hypothalamic-pituitary dysfunction. We report a case of hypothalamic hypopituitarism secondary to neurosarcoidosis complicated by adipsic diabetes insipidus (ADI). Initiation of anti-tumour necrosis factor-α (TNF-α) therapy resulted in both radiological disease remission and recovery of osmoregulated thirst appreciation after 3 months.

CASE SUMMARY

A 22-year-old man was referred to the endocrinology service with profound weight gain, polyuria and lethargy. Biochemical testing confirmed anterior hypopituitarism while posterior pituitary failure was confirmed by hypotonic polyuria responding to desmopressin. Magnetic resonance imaging (MRI) demonstrated extensive hypothalamic infiltration; neurosarcoidosis was confirmed histologically after excisional cervical lymph node biopsy. Osmoregulated thirst appreciation was normal early in the disease course despite severe hypotonic polyuria. However, subsequent subjective loss of thirst appreciation and development of severe hypernatraemia in the setting of normal cognitive function indicated onset of ADI.

MANAGEMENT

Clinical management involved daily weighing, regular plasma sodium measurement, fixed daily fluid intake and oral desmopressin. We initiated immunosuppressive therapy with pulsed intravenous anti-TNF-α therapy (infliximab) after multidisciplinary team consultation.

OUTCOME

Infliximab therapy resulted in successful radiological disease remission and complete recovery of osmoregulated thirst appreciation. This was confirmed by subjective return of thirst response and maintenance of plasma sodium in the normal range in the absence of close biochemical monitoring.

Autoimmune encephalitis associated with Ma2 antibodies and immune checkpoint inhibitor therapy

Immune checkpoint inhibitors have transformed the treatment of advanced malignancy, while increasing the risk of immune-related adverse events. A 56-year-old woman who had received nivolumab for stage 4 renal cell carcinoma subsequently developed altered behaviour, memory deficits and worsening of previously stable epilepsy. MR scan of the brain showed bilateral FLAIR (fluid-attenuated inversion recovery) hyperintensity of the mesial temporal lobes, and there were anti-Ma2 antibodies in both serum and cerebrospinal fluid. She was treated with corticosteroids but developed further clinical relapses requiring immunoglobulin and rituximab. The immune-related adverse events relating to immune checkpoint inhibitors are an emerging challenge for the neurologist. Some cases are refractory and require serial immunosuppression.

Evaluating the feasibility and preliminary efficacy of a Cognitive Occupation-Based programme for people with Multiple Sclerosis (COB-MS): protocol for a feasibility cluster-randomised controlled trial

BACKGROUND

Cognitive difficulties experienced by people with multiple sclerosis (MS) impact their quality of life and daily functioning, from childcare and work, to social and self-care activities. Despite the high prevalence of cognitive difficulties seen in MS, there is a lack of developed programmes that target cognition, while also supporting patients by helping them to function well in everyday life. The Cognitive Occupation-Based programme for people with MS (COB-MS) was developed as a holistic, individualised cognitive rehabilitation intervention. It addresses the wide-ranging symptoms and functional difficulties that present in MS, including the ability to maintain employment, social activities, home management and self-care. The aim of the current research is to evaluate the feasibility and preliminary efficacy of COB-MS for people with MS. The focus is on feasibility outcomes as well as functioning associated with cognitive difficulty and secondary outcomes related to cognition, fatigue and quality of life.

METHODS

One hundred and twenty people with MS will be assigned to participate in either the COB-MS programme or a treatment as usual, wait-list control group as part of this single-blind, cluster-randomised controlled feasibility and preliminary efficacy trial of the COB-MS programme. The COB-MS group will participate in an eight-session occupational-based cognitive rehabilitation programme over 9 weeks. The primary outcome measure is the goal attainment scaling at 12 weeks. Participants will be assessed pre-intervention, post-intervention and at 12 weeks post-intervention and 6 months post-intervention. Qualitative evaluations of participants' perspectives will also be examined as part of the feasibility study.

DISCUSSION

Results will provide recommendations for a future definitive trial of COB-MS, with respect to both feasibility and preliminary, clinical efficacy. In the event that results indicate efficacy, study findings will suggest that COB-MS requires consideration as a means of enhancing cognitive and daily functioning in people living with MS.

TRIAL REGISTRATION

ISRCTN: ISRCTN11462710. Registered on 9 September 2019.

Clinically isolated syndromes or clinically isolated patients? A patient and clinician perspective on the utility of CIS as a diagnosis

BACKGROUND

The term "Clinically Isolated Syndrome" (CIS) was introduced to describe a first clinical neurologic episode suggestive of an inflammatory demyelinating CNS disorder. Thereafter, the risk of developing clinically definite multiple sclerosis ranges from 20% to 80%, depending on a number of prognostic factors. Although the concept of CIS has been an important component in improving our understanding of risk levels in Multiple Sclerosis and prognosis, communicating uncertainty in this context remains a challenge for both patients and their clinicians. We therefore wished to explore both the patients understanding of the concept of CIS and the subsequent impact of a diagnosis. We also explored the concept of CIS from the clinician's perspective.

METHODS

The study uses a qualitative descriptive design involving both a semi-structured interview of patients with CIS as well as a short questionnaire sent to practising clinicians in the Republic of Ireland. Narrative data was coded onto themes.

RESULTS

Thirty CIS patients were interviewed. The majority of patients understood the term "CIS" but not the link between CIS and MS. Two themes were identified: emotional reactions following CIS diagnosis; and terminology and communication. Confusion and anxiety among patients due to inconsistent communication of CIS was identified. Of the thirty-three clinicians surveyed, only thirty-nine per cent found the term "CIS" clinically useful. Eighteen per cent of clinicians diagnosed MS from the CIS case vignette provided.

CONCLUSION

In the diagnosis of a first demyelinating event, use of the term "CIS" is confusing to patients and inconsistent among clinicians. We suggest that the term "CIS" be abandoned in favour of terminology that reflects both its pathogenesis and inherent risk of subsequent MS.

Co-incident primary progressive multiple sclerosis and hereditary spastic paraplegia (SPG4) - a case report

The cause of progressive disability in Primary Progressive Multiple Sclerosis (PPMS) is unknown. Pathogenic genes have been described in some MS cases that may contribute to progressive disability, independent of immune - mediated mechanisms (Jia et al., 2018). The autosomal dominant SPG4 (Spastin) mutation is the most common genotype in Hereditary Spastic Paraplegia (Solowska and Baas, 2015) and has been found in some patients with Relapsing Remitting Multiple Sclerosis (Mead et al., 2001, Yazici et al., 2013). Here, we describe the novel association of PPMS and the SPG4 (Spastin) mutation, in a patient with a family history of Hereditary Spastic Paraplegia, and discuss the therapeutic implications. While this single case report cannot discrimiate between simple co-occurence and the possibility of a pathogenic association, our report invites larger scale investigation.

Does long-term partial sodium channel blockade alter disease progression in MS? Evidence from a retrospective study

BACKGROUND

There is accumulating evidence that long-term disability and disease progression in multiple sclerosis (MS) are due to prolonged sodium channel opening along demyelinated axons. Despite good evidence in animal models of MS that partial voltage-gated sodium channel (VGSC) blockade reduces disease progression, little is known about its effects in patients, despite widespread use of such agents in the symptomatic management of MS.

OBJECTIVE

To determine if long-term exposure to the VGSC-blocking drug carbamazepine (CBZ) alters disease progression in MS.

METHODS

Using a retrospective chart review of patients diagnosed with MS, we compared progression of disability between patients exposed the VGSC blocker CBZ with those who were not exposed to the drug. Both whole-group and matched case-control analyses were performed after correcting for the influence of age, gender, MS subtype, expanded disability status score at diagnosis, use of disease-modifying therapy, and year of initial therapy. The multiple sclerosis severity scale (MSSS) was used as a measure of disease severity. The primary outcome measure was MSSS score difference between groups.

RESULTS

Four hundred patients were included; 51 received CBZ symptomatic therapy (average duration of therapy 27 months). There was no significant difference in mean MSSS between the two groups in either the whole group comparison (p = 0.63) or the matched analysis (p = 0.12).

CONCLUSION

Despite preclinical evidence suggesting a neuroprotective role of VGSC blockers in animal models of MS, this retrospective study suggests that long-term exposure to the VGSC-blocking drug CBZ fails to alter long-term disability and disease progression in MS patients.

Getting a handle on complicated migraine

We describe a case of a 45-year-old man who presented with a transient syndrome consisting of headache with neurological deficits. Neuroimaging including brain angiography was normal. Cerebrospinal fluid (CSF) analysis revealed an elevated protein and lymphocytic pleocytosis. The diagnosis of a syndrome of Headache and Neurological Deficits with CSF Lymphocytosis (HaNDL) was made after excluding all the other possible causes for the patient's presentation. He made an excellent recovery following a short course of naproxen sodium.