De novo deleterious genetic variations target a biological network centered on Aβ peptide in early-onset Alzheimer disease

We hypothesized that de novo variants (DNV) might participate in the genetic determinism of sporadic early-onset Alzheimer disease (EOAD, onset before 65 years). We investigated 14 sporadic EOAD trios first by array-comparative genomic hybridization. Two patients carried a de novo copy number variation (CNV). We then performed whole-exome sequencing in the 12 remaining trios and identified 12 non-synonymous DNVs in six patients. The two de novo CNVs (an amyloid precursor protein (APP) duplication and a BACE2 intronic deletion) and 3/12 non-synonymous DNVs (in PSEN1, VPS35 and MARK4) targeted genes from a biological network centered on the Amyloid beta (Aβ) peptide. We showed that this a priori-defined genetic network was significantly enriched in amino acid-altering DNV, compared with the rest of the exome. The causality of the APP de novo duplication (which is the first reported one) was obvious. In addition, we provided evidence of the functional impact of the following three non-synonymous DNVs targeting this network: the novel PSEN1 variant resulted in exon 9 skipping in patient's RNA, leading to a pathogenic missense at exons 8-10 junction; the VPS35 missense variant led to partial loss of retromer function, which may impact neuronal APP trafficking and Aβ secretion; and the MARK4 multiple nucleotide variant resulted into increased Tau phosphorylation, which may trigger enhanced Aβ-induced toxicity. Despite the difficulty to recruit Alzheimer disease (AD) trios owing to age structures of the pedigrees and the genetic heterogeneity of the disease, this strategy allowed us to highlight the role of de novo pathogenic events, the putative involvement of new genes in AD genetics and the key role of Aβ network alteration in AD.

Localization of Hidden Insulinomas with ⁶⁸Ga-DOTA-Exendin-4 PET/CT: A Pilot Study

(111)In-DOTA-exendin-4 SPECT/CT has been shown to be highly efficient in the detection of insulinomas. We aimed at determining whether novel PET/CT imaging with [Nle(14),Lys(40)(Ahx-DOTA-(68)Ga)NH2]exendin-4 ((68)Ga-DOTA-exendin-4) is feasible and sensitive in detecting benign insulinomas.

METHODS

(68)Ga-DOTA-exendin-4 PET/CT and (111)In-DOTA-exendin-4 SPECT/CT were performed in a randomized cross-over order on 5 patients with endogenous hyperinsulinemic hypoglycemia. The gold standard for comparison was the histologic diagnosis after surgery.

RESULTS

In 4 patients histologic diagnosis confirmed a benign insulinoma, whereas one patient refused surgery despite a positive (68)Ga-DOTA-exendin-4 PET/CT scan. In 4 of 5 patients, previously performed conventional imaging (CT or MR imaging) was not able to localize the insulinoma. (68)Ga-DOTA-exendin-4 PET/CT correctly identified the insulinoma in 4 of 4 patients, whereas (111)In-DOTA-exendin-4 SPECT/CT correctly identified the insulinoma in only 2 of 4 patients.

CONCLUSION

These preliminary data suggest that the use of (68)Ga-DOTA-exendin-4 PET/CT in detecting hidden insulinomas is feasible.

Electrophysiological diagnosis of Guillain-Barré syndrome subtype: could a single study suffice?

BACKGROUND

Serial electrophysiology has been suggested as essential for accurate diagnosis in Guillain-Barré syndrome (GBS). However, whether more adapted electrophysiological criteria may allow a single study to be sufficient is unknown.

METHODS

We retrospectively reviewed records of 365 consecutive patients with GBS from Birmingham, U.K., and Garches, France, admitted between 1998 and 2013. Electrophysiology was analysed using existing criteria as well as a set of modified criteria, developed using sensitive and specific cut-off values for demyelination and incorporating new knowledge on electrophysiology of axonal GBS. We compared diagnostic rates and classification changes using modified criteria with published literature relating to serial studies.

RESULTS

With existing criteria, we found similar proportions of acute inflammatory demyelinating polyradiculoneuropathy (AIDP) (71.5% vs. 72%; p=1), axonal GBS (17.5% vs. 14.7%; p=0.62) and equivocal forms (9.9% vs. 13.3%; p=0.41) to the previous studies considered. With modified criteria, we identified comparable rates of AIDP (56.2% vs. 58.7%; p=0.70), axonal GBS (35.1% vs. 36%; p=0.89) and equivocal forms (7.7% vs. 5.3%; p=0.63) with a single nerve conduction study as compared with when serial electrophysiology was used in previous analyses. We observed an identical diagnostic shift from AIDP to axonal GBS with modified criteria as that described with serial studies (21.5% vs. 18.5%; p=0.72). Classification changes with modified criteria correlated significantly with performing of electrophysiology ≤7 days after symptom onset (p=0.045), indicating their greater usefulness in earlier disease stages.

CONCLUSIONS

A single electrophysiological study may suffice to establish the ultimate electrodiagnosis of GBS subtype if the proposed modified electrodiagnostic criteria are used.

Energy flow analysis during the tennis serve: comparison between injured and noninjured tennis players

BACKGROUND

Energy flow has been hypothesized to be one of the most critical biomechanical concepts related to tennis performance and overuse injuries. However, the relationships among energy flow during the tennis serve, ball velocity, and overuse injuries have not been assessed.

PURPOSE

To investigate the relationships among the quality and magnitude of energy flow, the ball velocity, and the peaks of upper limb joint kinetics and to compare the energy flow during the serve between injured and noninjured tennis players.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

The serves of expert tennis players were recorded with an optoelectronic motion capture system. The forces and torques of the upper limb joints were calculated from the motion captures by use of inverse dynamics. The amount of mechanical energy generated, absorbed, and transferred was determined by use of a joint power analysis. Then the players were followed during 2 seasons to identify upper limb overuse injuries with a questionnaire. Finally, players were classified into 2 groups according to the questionnaire results: injured or noninjured.

RESULTS

Ball velocity increased and upper limb joint kinetics decreased with the quality of energy flow from the trunk to the hand + racket segment. Injured players showed a lower quality of energy flow through the upper limb kinetic chain, a lower ball velocity, and higher rates of energy absorbed by the shoulder and elbow compared with noninjured players.

CONCLUSION

The findings of this study imply that improper energy flow during the tennis serve can decrease ball velocity, increase upper limb joint kinetics, and thus increase overuse injuries of the upper limb joints.

[2012 literature review on peripheral neuropathies: immune neuropathies (treatments excluded)]

In 2012, interest remains high in the field of dysimmune neuropathies, chiefly concerning Guillain-Barré syndrome (GBS). The pathophysiological mechanisms are now better known but electrophysiological criteria should be updated. The risk of GBS in H1N1 vaccination is now well evaluated. Nerve ultrasonography provides new prospects for diagnosis and follow-up of dysimmune neuropathies but cannot substitute for electrophysiology. This paper aims to present some noteworthy articles published in 2012 in the field of dysimmune neuropathies.

Glucagon-like peptide-1 receptor imaging for the localisation of insulinomas: a prospective multicentre imaging study

BACKGROUND

Small benign insulinomas are hard to localise, leading to difficulties in planning of surgical interventions. We aimed to prospectively assess the insulinoma detection rate of single-photon emission CT in combination with CT (SPECT/CT) with a glucagon-like peptide-1 receptor avid radiotracer, and compare detection rates with conventional CT/MRI techniques.

METHODS

In our prospective imaging study, we enrolled adults aged 25-81 years at centres in Germany, Switzerland, and the UK. Eligible patients had proven clinical and biochemical endogenous hyperinsulinaemic hypoglycaemia and no evidence for metastatic disease on conventional imaging. CT/MRI imaging was done at referring centres according to standard protocols. At three tertiary nuclear medicine centres, we used whole body planar images and SPECT/CT of the abdomen up to 168 h after injection of (111)In-[Lys40(Ahx-DTPA-(111)In)NH2]-exendin-4 ((111)In-DTPA-exendin-4) to identify insulinomas. Consenting patients underwent surgery and imaging findings were confirmed histologically.

FINDINGS

Between Oct 1, 2008, and Dec 31, 2011, we recruited 30 patients. All patients underwent (111)In-DTPA-exendin-4 imaging, 25 patients underwent surgery (with histological analysis), and 27 patients were assessed with CT/MRI. (111)In-DTPA-exendin-4 SPECT/CT correctly detected 19 insulinomas and four additional positive lesions (two islet-cell hyperplasia and two uncharacterised lesions) resulting in a positive predictive value of 83% (95% CI 62-94). One true negative (islet-cell hyperplasia) and one false negative (malignant insulinoma) result was identified in separate patients by (111)In-DTPA-exendin-4 SPECT/CT. Seven patients (23%) were referred to surgery on the basis of (111)In-DTPA-exendin-4 imaging alone. For 23 assessable patients, (111)In-DTPA-exendin-4 SPECT/CT had a higher sensitivity (95% [95% CI 74-100]) than did CT/MRI (47% [27-68]; p=0.011).

INTERPRETATION

(111)In-DTPA-exendin-4 SPECT/CT could provide a good second-line imaging strategy for patients with negative results on initial imaging with CT/MRI.

FUNDING

Oncosuisse, the Swiss National Science Foundation, and UK Department of Health.

Mental health training experiences among Haitian healthcare workers post-earthquake 2010

BACKGROUND

After the 2010 earthquake in Haiti, the large number of persons with major limb damage, amputations, shock, trauma, anxiety and depression placed a severe strain on mental health (MH) services.

PURPOSE

This qualitative study describes the impact and acceptability of a Mental Health Training Program (MHTP) implemented in the north of Haiti after the earthquake.

METHODS

A total of 113 healthcare workers (HCWs) participated in a training program designed to build local MH care capacity. The training curriculum draws on literature related to MH and the impact of the Haiti earthquake. Two focus groups were conducted with 16 HCWs; discussions centred on the personal and professional impact and acceptability of the training program.

DISCUSSION

Results demonstrated that the MHTP changed the HCWs' perceptions about MH issues and provided them with the knowledge and skills to respond to growing community MH needs. Acceptability of the MHTP was related to the content covered, to the delivery mode of the content and to the cultural appropriateness of the program.

CONCLUSIONS

Disasters of different types will continue to occur and to impact MH in communities around the world. MH training will allow nurses to quickly and effectively respond to disasters. A coordinated emergency plan that is subject to frequent review, rehearsal and evaluation is also essential.

Placebo-controlled trial of rituximab in IgM anti-myelin-associated glycoprotein neuropathy

OBJECTIVE

To determine whether rituximab 375 mg/m(2) was efficacious in patients with immunoglobulin M (IgM) anti-myelin-associated glycoprotein antibody demyelinating neuropathy (IgM anti-MAG demyelinating neuropathy).

METHODS

Fifty-four patients with IgM anti-MAG demyelinating neuropathy were enrolled in this randomized, double-blind, placebo-controlled trial. The inclusion criteria were inflammatory neuropathy cause and treatment (INCAT) sensory score (ISS) ≥4 and visual analog pain scale >4 or ataxia score ≥2. The primary outcome was mean change in ISS at 12 months.

RESULTS

Twenty-six patients were randomized to a group receiving 4 weekly infusions of 375 mg/m(2) rituximab, and 28 patients to placebo. Intention-to-treat analysis, with imputation of missing ISS values by the last observation carried forward method, showed a lack of mean change in ISS at 12 months, 1.0 ± 2.7 in the rituximab group, and 1.0 ± 2.8 in the placebo group. However, changes were observed, in per protocol analysis at 12 months, for the number of patients with an improvement of at least 2 points in the INCAT disability scale (p = 0.027), the self-evaluation scale (p = 0.016), and 2 subscores of the Short Form-36 questionnaire.

CONCLUSIONS

Although primary outcome measures provide no evidence to support the use of rituximab in IgM anti-MAG demyelinating neuropathy, there were improvements in several secondary outcomes in per protocol analysis.

LEVEL OF EVIDENCE

This study provides Class I evidence that rituximab is ineffective in improving ISS in patients with IgM anti-MAG demyelinating neuropathy.

Acute toxoplasmosis mimicking melanoma metastases: review of conditions causing false-positive results on (18)F-FDG PET/CT

Invasive malignant melanoma is the most common fatal form of skin cancer. Fluorine-18-fluorodeoxyglucose positron emission tomography-computed tomography demonstrates a very high sensitivity and specificity for the detection of melanoma metastases. Here, we report an unusual case of toxoplasma lymphadenitis in a male adult patient mimicking a malignant cervical lymphadenopathy. Toxoplasmosis is a zoonosis caused by the intracellular parasite Toxoplasma gondii, which is usually asymptomatic in immunocompetent hosts.

Proximal giant neurofilamentous axonopathy in mice genetically engineered to resist calpain and caspase cleavage of α-II spectrin

We use 1,2-diacetylbenzene (1,2-DAB) to probe molecular mechanisms of proximal giant neurofilamentous axonopathy (PGNA), a pathological hallmark of amyotrophic lateral sclerosis. The spinal cord proteome of rodents displaying 1,2-DAB PGNA suggests a reduction in the abundance of α-II spectrin (Spna2), a key protein in the maintenance of axonal integrity. Protein immunoblotting indicates that this reduction is due to Spna2 degradation. We investigated the importance of such degradation in 1,2-DAB PGNA. Spna2 mutant mice lacking a calpain- and/or caspase-sensitive domain (CSD), thus hypothetically resistant to 1,2-DAB, and wild-type littermates, were treated with 1,2-DAB, 35 mg/kg/day, or saline control, for 3 weeks. 1,2-DAB induced motor weakness and PGNA, irrespective of the genotype. Spna2-calpain breakdown products were not detected in mutant mice, which displayed a normal structure of the nervous system under saline treatment. Intriguingly, treatment with 1,2-DAB reduced the abundance of the caspase-specific 120-kDa Spna2 breakdown products. Our findings indicate that degradation of Spna2 by calpain- and/or caspase is not central to the pathogenesis of 1,2-DAB axonopathy. In addition, the Spna2-CSD seems to be not required for the maintenance of the cytoskeleton integrity. Our conceptual framework offers opportunities to study the role of calpain-caspase cross talk, including that of the protease degradomics, in models of axonal degeneration.

How does the tennis serve technique influence the serve-and-volley?

In tennis, a high ball velocity and a fast run toward the net are key features to successful performance of "serve-and-volley" players. For the serve, tennis players can use two techniques: the foot-up (FU) or foot-back (FB) technique. The aim of this study was to determine if the running time toward the net after the serve and the ball velocity (V(ball)) vary between these two techniques. Moreover we analysed the angular momentum values of the trunk and of the arm holding the racquet. Fifteen expert tennis players performed six successful serve-and-volleys with both techniques. Running time to the net is significantly lower for FB, whereas V(ball) is significantly higher for FU. Trunk and arm angular momentums about the transverse axis are significantly higher with FU before ball impact. A significant correlation (r = 0.81, P < 0.001) exists between changes in the maximal trunk angular momentum and in running time to the net between the two serve techniques. A significant correlation (r = 0.84, P < 0.001) also exists between changes in the maximal trunk angular momentum and in V(ball) between the two serve techniques. According to these results, FB is the best technique for moving as quickly as possible to the net because of a lower trunk angular momentum.