Long-term success of low-frequency subthalamic nucleus stimulation for Parkinson's disease depends on tremor severity and symptom duration

Patients with Parkinson's disease can develop axial symptoms, including speech, gait and balance difficulties. Chronic high-frequency (>100 Hz) deep brain stimulation can contribute to these impairments while low-frequency stimulation (<100 Hz) may improve symptoms but only in some individuals. Factors predicting which patients benefit from low-frequency stimulation in the long term remain unclear. This study aims to confirm that low-frequency stimulation improves axial symptoms, and to go further to also explore which factors predict the durability of its effects. We recruited patients who developed axial motor symptoms while using high-frequency stimulation and objectively assessed the short-term impact of low-frequency stimulation on axial symptoms, other aspects of motor function and quality of life. A retrospective chart review was then conducted on a larger cohort to identify which patient characteristics were associated with not only the need to trial low-frequency stimulation, but also those which predicted its sustained use. Among 20 prospective patients, low-frequency stimulation objectively improved mean motor and axial symptom severity and quality of life in the short term. Among a retrospective cohort of 168 patients, those with less severe tremor and those in whom axial symptoms had emerged sooner after subthalamic nucleus deep brain stimulation were more likely to be switched to and remain on long-term low-frequency stimulation. These data suggest that low-frequency stimulation results in objective mean improvements in overall motor function and axial symptoms among a group of patients, while individual patient characteristics can predict sustained long-term benefits. Longer follow-up in the context of a larger, controlled, double-blinded study would be required to provide definitive evidence of the role of low-frequency deep brain stimulation

Imaging of Hereditary Hemorrhagic Telangiectasia

This pictorial review is based on our experience of the follow-up of 120 patients at our multidisciplinary center for hereditary hemorrhagic telangiectasia (HHT). Rendu-Osler-Weber disease or HHT is a multiorgan autosomal dominant disorder with high penetrance, characterized by epistaxis, mucocutaneous telangiectasis, and visceral arteriovenous malformations (AVMs). The research on gene mutations is fundamental and family screening by clinical examination, chest X-ray, research of pulmonary shunting, and abdominal color Doppler sonography is absolutely necessary. The angioarchitecture of pulmonary AVMs can be studied by unenhanced multidetector computed tomography; however, all other explorations of liver, digestive bowels, or brain require administration of contrast media. Magnetic resonance angiography is helpful for central nervous system screening, in particular for the spinal cord, but also for pulmonary, hepatic, and pelvic AVMs. Knowledge of the multiorgan involvement of HHT, mechanism of complications, and radiologic findings is fundamental for the correct management of these patients

Multigene Molecular Systematics Confirm Species Status of Morphologically Convergent Pagurus Hermit Crabs

Introduction: In spite of contemporary morphological taxonomy appraisals, apparent high morphological similarity raises uncertainty about the species status of certain Pagurus hermit crabs. This is exemplified between two European species, Pagurus excavatus (Herbst, 1791) and Pagurus alatus (Fabricius 1775), whose species status is still difficult to resolve using morphological criteria alone. Methodology/Principal Findings: To address such ambiguities, we used combinations of Maximum Likelihood (ML) and Bayesian Inference (BI) methods to delineate species boundaries of P. alatus and P. excavatus and formulate an intermediate Pagurus phylogenetic hypothesis, based upon single and concatenated mitochondrial (cytochrome oxidase I [COI]) and nuclear (16S and 28s ribosomal RNA) gene partitions. The molecular data supported the species status of P. excavatus and P. alatus and also clearly resolved two divergent clades within hermit crabs from the Northeast Atlantic Ocean and the Mediterranean Sea. Conclusions/Significance: Despite the abundance and prominent ecological role of hermit crabs, Pagurus, in North East Atlantic Ocean and Mediterranean Sea ecosystems, many important aspects of their taxonomy, biology, systematics and evolution remain poorly explored. The topologies presented here should be regarded as hypotheses that can be incorporated into the robust and integrated understanding of the systematic relationships within and between species of the genus Pagurus inhabiting the Northeast Atlantic Ocean and the Mediterranean Sea

Sentinel lymph node mapping in endometrial cancer: A literature review and state of the art

Objective: Sentinel lymph node biopsy has proven safe and feasible in a number of gynecologic cancers such as vulvar cancer, cervical cancer, and endometrial cancer. The aim of sentinel node mapping is to decrease the morbidity associated with a complete lymphadenectomy, while also increasing the detection rate of small lymph node metastases. The scope of this review is to critically appraise the published literature on (Sentinel Lymph Node) SLN procedure in endometrial cancer (EC). Methods: We run a PubMed search for publications in English using “endometrial cancer” and “sentinel node” as key words. All abstracts from 2005 to December 2015 were reviewed. We excluded studies aimed to determine the risk of metastasis in the remaining non-SLNs when the SLN is positive, studies that only reported on successfully mapped patients, those where different types of gynecological cancers other than EC and/ or atypical endometrial hyperplasia were included and those studies with less than 30 cases. Results: 23 studies met the inclusion criteria. The overall detection rate of sentinel nodes after cervical injection ranged from 62% to 100%, while it was 73% to 95% after corporeal injection. All studies with n of cases ≥ 100 had overall detection rates of &gt;80%. In terms of product/tracer used, Technetium colloid, blue dye and ICG were used either alone or in combination. Detection rates were good for all three products, however, detection rates were higher when blue dye was combined with Technetium (Tc) or Indocyanine Green (ICG). The injection site influenced the pattern of sentinel mapping with para-aortic SLNs being found more often using corporeal and deeper (3–4 cm) cervical injection techniques. Studies in which the protocol included a systematic para-aortic lymphadenectomy had higher detection of para-aortic SLNs, as well as isolated para-aortic metastases. Conclusion: Sentinel lymph node mapping for endometrial cancer balances the need to assess nodal disease with the low likelihood of nodal metastasis for most patients. It is a technique with minimal morbidity, sparing the need for a full lymphadenectomy and its associated higher morbidity potentially leading to a greater utilization by gynecologic surgeons in the future. Achieving high bilateral SLN detection rates and low false-negative rates is mandatory to implement the SLN mapping as a routine component of clinical practice

Transcranial direct current stimulation modulates motor responses evoked by repetitive transcranial magnetic stimulation

Introduction Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are non-invasive techniques able to induce changes in corticospinal excitability. In this study, we combined rTMS and tDCS to understand possible interactions between the two techniques, and investigate whether they are polarity dependent. Materials and methods Eleven healthy subjects participated in the study. Each patient underwent both anodal and cathodal conditioning tDCS in two separate sessions; brief 5 Hz-rTMS trains were delivered over the primary motor cortex at an intensity of 120% the resting motor threshold (RMT) before tDCS (T0), immediately after (T1) and 10 min after current offset (T2). We then analysed changes induced by cathodal and anodal tDCS on TMS variables. Results Our results showed that in both anodal and cathodal sessions, the motor evoked potential (MEP) amplitude increased significantly in size before stimulation (T0). Conversely, after anodal tDCS, the MEP facilitation measured at T1 and T2 was absent, whereas after cathodal tDCS it was preserved. Conclusions Our findings provide new direct neurophysiological evidence that tDCS influences primary motor cortex excitability