Antibiotic tolerance among clinical isolates: mechanisms, detection, prevalence, and significance.

SUMMARYAntibiotic treatment failures in the absence of resistance are not uncommon. Recently, attention has grown around the phenomenon of antibiotic tolerance, an underappreciated contributor to recalcitrant infections first detected in the 1970s. Tolerance describes the ability of a bacterial population to survive transient exposure to an otherwise lethal concentration of antibiotic without exhibiting resistance. With advances in genomics, we are gaining a better understanding of the molecular mechanisms behind tolerance, and several studies have sought to examine the clinical prevalence of tolerance. Attempts have also been made to assess the clinical significance of tolerance through in vivo infection models and prospective/retrospective clinical studies. Here, we review the data available on the molecular mechanisms, detection, prevalence, and clinical significance of genotypic tolerance that span ~50 years. We discuss the need for standardized methodology and interpretation criteria for tolerance detection and the impact that methodological inconsistencies have on our ability to accurately assess the scale of the problem. In terms of the clinical significance of tolerance, studies suggest that tolerance contributes to worse outcomes for patients (e.g., higher mortality, prolonged hospitalization), but historical data from animal models are varied. Furthermore, we lack the necessary information to effectively treat tolerant infections. Overall, while the tolerance field is gaining much-needed traction, the underlying clinical significance of tolerance that underpins all tolerance research is still far from clear and requires attention.

Escherichia coli recombinant expression of SARS-CoV-2 protein fragments.

We have developed a method for the inexpensive, high-level expression of antigenic protein fragments of SARS-CoV-2 proteins in Escherichia coli. Our approach uses the thermophilic family 9 carbohydrate-binding module (CBM9) as an N-terminal carrier protein and affinity tag. The CBM9 module was joined to SARS-CoV-2 protein fragments via a flexible proline-threonine linker, which proved to be resistant to E. coli proteases. Two CBM9-spike protein fragment fusion proteins and one CBM9-nucleocapsid fragment fusion protein largely resisted protease degradation, while most of the CBM9 fusion proteins were degraded at some site in the SARS-CoV-2 protein fragment. All of the fusion proteins were highly expressed in E. coli and the CBM9-ID-H1 fusion protein was shown to yield 122 mg/L of purified product. Three purified CBM9-SARS-CoV-2 fusion proteins were tested and found to bind antibodies directed to the appropriate SARS-CoV-2 antigenic regions. The largest intact CBM9 fusion protein, CBM9-ID-H1, incorporates spike protein amino acids 540-588, which is a conserved region overlapping and C-terminal to the receptor binding domain that is widely recognized by human convalescent sera and contains a putative protective epitope.

Syntaxins 6 and 8 facilitate tau into secretory pathways.

Tau pathology initiates in defined brain regions and is known to spread along neuronal connections as symptoms progress in Alzheimer's disease (AD) and other tauopathies. This spread requires the release of tau from donor cells, but the underlying molecular mechanisms remained unknown. Here, we established the interactome of the C-terminal tail region of tau and identified syntaxin 8 (STX8) as a mediator of tau release from cells. Similarly, we showed the syntaxin 6 (STX6), part of the same SNARE family as STX8 also facilitated tau release. STX6 was previously genetically linked to progressive supranuclear palsy (PSP), a tauopathy. Finally, we demonstrated that the transmembrane domain of STX6 is required and sufficient to mediate tau secretion. The differential role of STX6 and STX8 in alternative secretory pathways suggests the association of tau with different secretory processes. Taken together, both syntaxins, STX6 and STX8, may contribute to AD and PSP pathogenesis by mediating release of tau from cells and facilitating pathology spreading.

Onset of hippocampal network aberration and memory deficits in P301S tau mice are associated with an early gene signature.

Hyperphosphorylation and deposition of tau in the brain characterizes frontotemporal dementia and Alzheimer's disease. Disease-associated mutations in the tau-encoding MAPT gene have enabled the generation of transgenic mouse models that recapitulate aspects of human neurodegenerative diseases, including tau hyperphosphorylation and neurofibrillary tangle formation. Here, we characterized the effects of transgenic P301S mutant human tau expression on neuronal network function in the murine hippocampus. Onset of progressive spatial learning deficits in P301S tau transgenic TAU58/2 mice were paralleled by long-term potentiation deficits and neuronal network aberrations during electrophysiological and EEG recordings. Gene-expression profiling just prior to onset of apparent deficits in TAU58/2 mice revealed a signature of immediate early genes that is consistent with neuronal network hypersynchronicity. We found that the increased immediate early gene activity was confined to neurons harbouring tau pathology, providing a cellular link between aberrant tau and network dysfunction. Taken together, our data suggest that tau pathology drives neuronal network dysfunction through hyperexcitation of individual, pathology-harbouring neurons, thereby contributing to memory deficits.

Role of EphA4 in Mediating Motor Neuron Death in MND.

Motor neuron disease (MND) comprises a group of fatal neurodegenerative diseases with no effective cure. As progressive motor neuron cell death is one of pathological characteristics of MND, molecules which protect these cells are attractive therapeutic targets. Accumulating evidence indicates that EphA4 activation is involved in MND pathogenesis, and inhibition of EphA4 improves functional outcomes. However, the underlying mechanism of EphA4's function in MND is unclear. In this review, we first present results to demonstrate that EphA4 signalling acts directly on motor neurons to cause cell death. We then review the three most likely mechanisms underlying this effect.

Peer review of mortality after hepatectomy in Australia.

BACKGROUND: The data within the Australian and New Zealand Audit of Surgical Mortality (ANZASM) provides a unique opportunity to consider the contributing factors to perioperative deaths as determined by peer review. Consideration of the factors contributing to mortality after hepatectomy can provide greater insight into how deaths can be prevented. The objective of this study was to determine the reasons for patient deaths post-hepatectomy in Australia. METHODS: ANZASM data from 1 January 2010 to 30 Jun 2017 was reviewed and all deaths following hepatectomy were selected for analysis. Assessors determinations of whether management could have been improved were reviewed, and then classified into groups of significant clinical events using thematic analysis with a data driven approach. RESULTS: The study included 88 deaths reported to ANZASM after hepatectomy. The assessors questioned the decision to operate in 23/88 (25%) patients with a further nine (10%) patients insufficiently investigated prior to resection. ANZASM assessors determined that there was a delay in recognising a significant complication in 16/88 (18%) patients. CONCLUSION: Multi-disciplinary decision making is strongly recommended when deciding which patients to treat with hepatic resection. Optimal care post-hepatectomy includes early recognition of complications and enactment of an adequate rescue plan.

Acceptability of receiving lifestyle advice at cervical, breast and bowel cancer screening.

Cancer screening could be an opportunity to deliver cancer prevention advice, but it is not known how such information would be received. We explored willingness to receive lifestyle advice in the context of the English National Health Service cervical, breast, and bowel (FS; flexible sigmoidoscopy) screening programmes. A population-based survey was conducted in 2016 to collect nationally representative data on willingness to receive lifestyle advice across cervical (n = 768), breast (n = 420) and FS (n = 308) screening programmes. Additional items assessed the impact of lifestyle advice on screening attendance, preference for receiving advice in the event of an abnormal screening result, and timing of advice. Most respondents were willing to receive lifestyle advice around the time of cancer screening (cervical 78.9%, breast 79.4%, FS 81.8%), and if their results were abnormal (cervical 86.3%, breast 83.0%, FS 85.1%). A small proportion indicated it may discourage future attendance (cervical 4.9%, breast 7.0%, FS 8.8%). Most preferred information to be delivered at the screening appointment (cervical 69.8%, breast 72.6%, FS 70.7%). There were no associations between sociodemographic characteristics and willingness to receive lifestyle advice at breast screening. For those intending to attend cervical screening, non-White ethnicity and higher education were associated with increased willingness to receive lifestyle advice. Women were more likely to be willing to receive advice at FS screening than men. Providing lifestyle advice at cancer screening is likely to be acceptable to the general population. The optimal approach for delivery needs careful consideration to minimise potential negative effects on screening attendance.

Retiring the term FTDP-17 as MAPT mutations are genetic forms of sporadic frontotemporal tauopathies.

See Josephs (doi:10.1093/brain/awx367) for a scientific commentary on this article.In many neurodegenerative disorders, familial forms have provided important insights into the pathogenesis of their corresponding sporadic forms. The first mutations associated with frontotemporal lobar degeneration (FTLD) were found in the microtubule-associated protein tau (MAPT) gene on chromosome 17 in families with frontotemporal degeneration and parkinsonism (FTDP-17). However, it was soon discovered that 50% of these families had a nearby mutation in progranulin. Regardless, the original FTDP-17 nomenclature has been retained for patients with MAPT mutations, with such patients currently classified independently from the different sporadic forms of FTLD with tau-immunoreactive inclusions (FTLD-tau). The separate classification of familial FTLD with MAPT mutations implies that familial forms cannot inform on the pathogenesis of the different sporadic forms of FTLD-tau. To test this assumption, this study pathologically assessed all FTLD-tau cases with a known MAPT mutation held by the Sydney and Cambridge Brain Banks, and compared them to four cases of four subtypes of sporadic FTLD-tau, in addition to published case reports. Ten FTLD-tau cases with a MAPT mutation (K257T, S305S, P301L, IVS10+16, R406W) were screened for the core differentiating neuropathological features used to diagnose the different sporadic FTLD-tau subtypes to determine whether the categorical separation of MAPT mutations from sporadic FTLD-tau is valid. Compared with sporadic cases, FTLD-tau cases with MAPT mutations had similar mean disease duration but were younger at age of symptom onset (55 ± 4 years versus 70 ± 6 years). Interestingly, FTLD-tau cases with MAPT mutations had similar patterns and severity of neuropathological features to sporadic FTLD-tau subtypes and could be classified into: Pick's disease (K257T), corticobasal degeneration (S305S, IVS10‰+‰16, R406W), progressive supranuclear palsy (S305S) or globular glial tauopathy (P301L, IVS10‰+‰16). The finding that the S305S mutation could be classified into two tauopathies suggests additional modifying factors. Assessment of our cases and previous reports suggests that distinct MAPT mutations result in particular FTLD-tau subtypes, supporting the concept that they are likely to inform on the varied cellular mechanisms involved in distinctive forms of sporadic FTLD-tau. As such, FTLD-tau cases with MAPT mutations should be considered familial forms of FTLD-tau subtypes rather than a separate FTDP-17 category, and continued research on the effects of different mutations more focused on modelling their impact to produce the very different sporadic FTLD-tau pathologies in animal and cellular models.

Peer review of mortality after pancreaticoduodenectomy in Australia.

BACKGROUND: The data within the Australian and New Zealand Audit of Surgical Mortality (ANZASM) provides a unique opportunity to consider the contributing factors to perioperative deaths as determined by peer review. Consideration of the factors contributing to mortality after pancreaticoduodenectomy (PD) can provide greater insight into how deaths can be prevented. METHODS: ANZASM data from 1 January 2010 to 30 Jun 2017 was reviewed and all deaths following PD were selected for analysis. Assessor's determination of whether management could have been improved were reviewed and classified into groups of significant clinical events using thematic analysis with a data driven approach. RESULTS: The study included 87 deaths reported to ANZASM after PD. Forty-two major complications were considered significant clinical events in 29/84 (35%) of patients. The assessor determined that there was a delay in recognising a significant complication in 18/84 (21%) of patients. In 14/84 (17%) of patients, ANZASM assessment questioned the decision to operate. CONCLUSION: Multi-disciplinary decision making is strongly recommended when deciding which patients to treat with PD. Late recognition, and therefore delayed action to treat complications, in almost a quarter of deaths is a significant finding that warrants consideration for clinicians involved in the postoperative care of PD patients.

Transmission of HIV-1 drug resistance mutations within partner-pairs: A cross-sectional study of a primary HIV infection cohort.

BACKGROUND: Transmission of human immunodeficiency virus type 1 (HIV-1) drug resistance mutations, particularly that of minority drug-resistant variants, remains poorly understood. Population-based studies suggest that drug-resistant HIV-1 is less transmissible than drug-susceptible viruses. We compared HIV-1 drug-resistant genotypes among partner-pairs in order to assess the likelihood of transmission of drug resistance mutations and investigate the role of minority variants in HIV transmission. METHODS AND FINDINGS: From 1992-2010, 340 persons with primary HIV-1 infection and their partners were enrolled into observational research studies at the University of Washington Primary Infection Clinic (UWPIC). Out of 50 partner-pairs enrolled, 36 (72%) transmission relationships were confirmed by phylogenetic distance analysis of HIV-1 envelope (env) sequences, and 31 partner-pairs enrolled after 1995 met criteria for this study. Drug resistance mutations in the region of the HIV-1 polymerase gene (pol) that encodes protease and reverse transcriptase were assessed by 454-pyrosequencing. In 25 partner-pairs where the transmission direction could be determined, 12 (48%) transmitters had 1-4 drug resistance mutations (23 total) detected in their HIV-1 populations at a median frequency of 6.0% (IQR 1.5%-98.7%, range 1.0%-99.6%). Of 10 major mutations detected in five transmitters at a frequency >95%, 100% (95% CI 69.2%-100%) were detected in recipients. All of these transmitters were antiretroviral (ARV)-naïve at the time of specimen collection. Fourteen mutations (eight major mutations and six accessory mutations) were detected in nine transmitters at low frequencies (1.0%-11.8%); four of these transmitters had previously received ARV therapy. Two (14% [95% CI 1.8%-42.8%]) G73S accessory mutations were detected in both transmitter and recipient. This number is not significantly different from the number expected based on the observed frequencies of drug-resistant viruses in transmitting partners. Limitations of this study include the small sample size and uncertainties in determining the timing of virus transmission and mutation history. CONCLUSIONS: Drug-resistant majority variants appeared to be commonly transmitted by ARV-naïve participants in our analysis and may contribute significantly to transmitted drug resistance on a population level. When present at low frequency, no major mutation was observed to be shared between partner-pairs; identification of accessory mutations shared within a pair could be due to transmission, laboratory artifact, or apolipoprotein B mRNA-editing enzyme, catalytic polypeptides (APOBECs), and warrants further study.

Determinants of willingness to receive healthy lifestyle advice in the context of cancer screening.

BACKGROUND: Providing lifestyle advice at cancer screening may help reduce the cancer burden attributable to health-related behaviour. We examined determinants of willingness to receive advice about several behavioural cancer risk factors. METHODS: A population-based sample of English adults eligible for cancer screening (n = 1221) completed items on willingness to receive lifestyle advice. Sociodemographic, psychological (risk perceptions, cancer risk factor awareness) and behavioural factors were used to predict interest in advice about diet, weight, physical activity, smoking and alcohol consumption. RESULTS: Two thirds (62-67%) reported interest in advice about diet, weight, and physical activity; 17% were willing to receive advice about smoking, and 32% about alcohol consumption. Willingness to receive advice was higher in those not adhering to guidelines for weight, physical activity, smoking and alcohol consumption (all p < 0.01). Non-White ethnicity was associated with interest in advice about diet, physical activity and smoking (all p < 0.01). Willingness to receive advice about diet, weight, physical activity and alcohol consumption increased with greater recognition of cancer risk factors (all p < 0.01). CONCLUSIONS: Willingness to receive lifestyle advice at cancer screening was high, suggesting this context may provide an opportunity to support behaviour change. Increasing awareness of cancer risk factors may facilitate interest in lifestyle advice.

Measuring Outcomes of Clinical Care: Victorian Emergency Laparotomy Audit Using Quality Investigator.

BACKGROUND: The Australian and New Zealand Audit of Surgical Mortality (ANZASM) National Report 2015 found that within the cohort of audited deaths, 85% were emergencies with acute life-threatening conditions, and by far, the most common procedures were laparotomy and colorectal procedures. Emergency laparotomy outcomes have shown improvement through audit and reporting in the UK. The purpose of this study was to determine the outcome of emergency laparotomy in the state of Victoria, Australia. METHOD: The Dr Foster Quality Investigator (DFQI) database was interrogated for a set of Australian Classification of Health Intervention (ACHI) codes defined by the authors as representing an emergency laparotomy. The dataset included patients who underwent emergency laparotomy from July 2007 to July 2016 in all Victorian hospitals. RESULTS: There were 23,115 emergency laparotomies conducted over 9 years in 66 hospitals. Inpatient mortality was 2036/23,115 (8.8%). Mortality in the adult population increased with age and reached 18.1% in those patients that were 80 years or older. 51.3% were females, and there was no significant difference in survival between genders. Patients with no recorded comorbidities had a mortality of 4.3%, whereas those with > 5 comorbidities had 19.3% mortality. CONCLUSION: Administrative data accessed via a tool such as DFQI can provide useful population data to guide further evidence-based improvement strategies. The mortality for emergency laparotomy within Victorian hospitals is comparable, if not better than that seen in overseas studies. There is a need to continue routine audit of mortality rates and implement systems improvement where necessary.

Systematic review and meta-analysis of hepatic resection versus transarterial chemoembolization for solitary large hepatocellular carcinoma.

BACKGROUND: Surgical techniques and pre-operative patient evaluation have improved since the initial development of the Barcelona clinic liver cancer staging system. The optimal treatment for solitary hepatocellular carcinoma ≥5 cm remains unclear. The aim of this study was to review the long-term survival outcomes of hepatic resection versus transarterial chemoembolisation (TACE) for solitary large tumours. METHODS: EMBASE, MEDLINE, Pubmed and the Cochrane database were searched for studies comparing resection with TACE for solitary HCC ≥5 cm. The primary outcome was overall survival at 1, 3 and 5 years. RESULTS: The meta-analysis combined the results of four cohort studies including 861 patients where 452 underwent hepatic resection and 409 were treated with TACE to an absence of viable tumour. The pooled HR for 3 year OS rate calculated using the random effects model was 0.60 (95% CI 0.46-0.79, p < 0.001; I2 = 54%, P = 0.087). The pooled HR for 5 year OS rate calculated using the random effects model was 0.59 (95% CI 0.43-0.81, p = 0.001; I2 = 80%, P = 0.002). CONCLUSION: Hepatic resection has been shown to result in greater survivability and time to disease progression than TACE for solitary HCC ≥5 cm. Where a patient is fit for surgery, has adequate liver function and a favourable tumour, resection should be considered.

Mutations in UPF3B, a member of the nonsense-mediated mRNA decay complex, cause syndromic and nonsyndromic mental retardation.

Nonsense-mediated mRNA decay (NMD) is of universal biological significance. It has emerged as an important global RNA, DNA and translation regulatory pathway. By systematically sequencing 737 genes (annotated in the Vertebrate Genome Annotation database) on the human X chromosome in 250 families with X-linked mental retardation, we identified mutations in the UPF3 regulator of nonsense transcripts homolog B (yeast) (UPF3B) leading to protein truncations in three families: two with the Lujan-Fryns phenotype and one with the FG phenotype. We also identified a missense mutation in another family with nonsyndromic mental retardation. Three mutations lead to the introduction of a premature termination codon and subsequent NMD of mutant UPF3B mRNA. Protein blot analysis using lymphoblastoid cell lines from affected individuals showed an absence of the UPF3B protein in two families. The UPF3B protein is an important component of the NMD surveillance machinery. Our results directly implicate abnormalities of NMD in human disease and suggest at least partial redundancy of NMD pathways.

Oral and Vaginal Tenofovir for Genital Herpes Simplex Virus Type 2 Shedding in Immunocompetent Women: A Double-Blind, Randomized, Cross-over Trial.

BACKGROUND: Tenofovir is a potent anti-human immunodeficiency virus (HIV) agent that decreased risk of herpes simplex virus type 2 (HSV-2) acquisition in HIV pre-exposure prophylaxis trials. Whether tenofovir has utility in established HSV-2 disease is unclear. METHODS: We randomized immunocompetent women with symptomatic HSV-2 infection to oral tenofovir disoproxil fumarate (TDF)/placebo vaginal gel, oral placebo/tenofovir (TFV) vaginal gel, or double placebo (ratio 2:2:1) in a one-way cross-over trial. Women collected genital swabs twice daily for HSV PCR during 4-week lead-in and 5-week treatment phases. The primary intent-to-treat end point was within-person comparison of genital HSV shedding and lesion rates. RESULTS: 64 women completed the lead-in phase and were randomized. Neither TDF nor TFV gel decreased overall shedding or lesion rate in the primary analysis; TFV gel decreased quantity of HSV DNA by -0.50 (-0.86-0.13) log10 copies/mL. In the per-protocol analysis, TDF reduced shedding (relative risk [RR] = 0.74, P = .006) and lesion rates (RR = 0.75, P = .032); quantity of virus shed decreased by 0.41 log10 copies/mL. CONCLUSIONS: Oral TDF modestly decreased HSV shedding and lesion rate, and quantity of virus shed when used consistently. Vaginal TFV gel decreased quantity of virus shed by 60%. In contrast to effects on HSV-2 acquisition, tenofovir is unlikely to provide clinically meaningful reductions in the frequency of HSV shedding or genital lesions. CLINICAL TRIALS REGISTRATION: NCT01448616.

Tau-targeting passive immunization modulates aspects of pathology in tau transgenic mice.

Immunization is increasingly recognized as a suitable therapeutic avenue for the treatment of neurological diseases such as Alzheimer's disease and other tauopathies. Tau is a key molecular player in these conditions and therefore represents an attractive target for passive immunization approaches. We performed such an approach in two independent tau transgenic mouse models of tauopathy, K369I tau transgenic K3 and P301L tau transgenic pR5 mice. The antibodies we used were either specific for full-length tau or tau phosphorylated at serine 404 (pS404), a residue that forms part of the paired helical filament (PHF)-1 phosphoepitope that characterizes tau neurofibrillary tangles in tauopathies. Although both pS404 antibodies had a similar affinity, they differed in isotype, and only passive immunization with the IgG2a/κ pS404-specific antibody resulted in a lower tangle burden and reduced phosphorylation of tau at the PHF1 epitope in K3 mice. In pR5 mice, the same antibody led to a reduced phosphorylation of the pS422 and PHF1 epitopes of tau. In addition, histological sections of the hippocampal dentate gyrus of the immunized pR5 mice displayed reduced pS422 staining intensities. These results show that passive immunization targeting tau can modulate aspects of tau pathology in tau transgenic mouse models, in an antibody isotype-specific manner. We show that passive immunization targeting the pathological phosphorylation site pS404 on human tau with a monoclonal IgG2a/κ, but not a IgG1/κ antibody, reduced hyperphosphorylation of tau and tangle burden in two independent mouse models of tau pathology. This shows that both specificity and isotype of phospho-tau (p-tau)-specific antibodies are important for therapeutically ameliorating tau pathology.

Early-onset axonal pathology in a novel P301S-Tau transgenic mouse model of frontotemporal lobar degeneration.

AIM: Tau becomes hyperphosphorylated in Alzheimer's disease (AD) and frontotemporal lobar degeneration (FTLD-tau), resulting in functional deficits of neurones, neurofibrillary tangle (NFT) formation and eventually dementia. Expression of mutant human tau in the brains of transgenic mice has produced different lines that recapitulate various aspects of FTLD-tau and AD. In this study, we characterized the novel P301S mutant tau transgenic mouse line, TAU58/2. METHODS: Both young and aged TAU58/2 mice underwent extensive motor testing, after which brain tissue was analysed with immunohistochemistry, silver staining, electron microscopy and Western blotting. Tissue from various FTLD subtypes and AD patients was also analysed for comparison. RESULTS: TAU58/2 mice presented with early-onset motor deficits, which became more pronounced with age. Throughout the brains of these mice, tau was progressively hyperphosphorylated resulting in increased NFT formation with age. In addition, frequent axonal swellings that stained intensively for neurofilament (NF) were present in young TAU58/2 mice prior to NFT formation. Similar axonal pathology was also observed in human FTLD-tau and AD. Interestingly, activated microglia were found in close proximity to neurones harbouring transgenic tau, but were not associated with NF-positive axonal swellings. CONCLUSIONS: In TAU58/2 mice, early tau pathology induces functional deficits of neurones associated with NF pathology. This appears to be specific to tau, as similar changes are observed in FTLD-tau, but not in FTLD with TDP-43 inclusions. Therefore, TAU58/2 mice recapitulate aspects of human FTLD-tau and AD pathology, and will become instrumental in studying disease mechanisms and therapeutics in the future.

Short-term suppression of A315T mutant human TDP-43 expression improves functional deficits in a novel inducible transgenic mouse model of FTLD-TDP and ALS.

The nuclear transactive response DNA-binding protein 43 (TDP-43) undergoes relocalization to the cytoplasm with formation of cytoplasmic deposits in neurons in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Pathogenic mutations in the TDP-43-encoding TARDBP gene in familial ALS as well as non-mutant human TDP-43 have been utilized to model FTD/ALS in cell culture and animals, including mice. Here, we report novel A315T mutant TDP-43 transgenic mice, iTDP-43(A315T), with controlled neuronal over-expression. Constitutive expression of human TDP-43(A315T) resulted in pronounced early-onset and progressive neurodegeneration, which was associated with compromised motor performance, spatial memory and disinhibition. Muscle atrophy resulted in reduced grip strength. Cortical degeneration presented with pronounced astrocyte activation. Using differential protein extraction from iTDP-43(A315T) brains, we found cytoplasmic localization, fragmentation, phosphorylation and ubiquitination and insolubility of TDP-43. Surprisingly, suppression of human TDP-43(A315T) expression in mice with overt neurodegeneration for only 1 week was sufficient to significantly improve motor and behavioral deficits, and reduce astrogliosis. Our data suggest that functional deficits in iTDP-43(A315T) mice are at least in part a direct and transient effect of the presence of TDP-43(A315T). Furthermore, it illustrates the compensatory capacity of compromised neurons once transgenic TDP-43 is removed, with implications for future treatments.

Mutations in FRMD7, a newly identified member of the FERM family, cause X-linked idiopathic congenital nystagmus.

Idiopathic congenital nystagmus is characterized by involuntary, periodic, predominantly horizontal oscillations of both eyes. We identified 22 mutations in FRMD7 in 26 families with X-linked idiopathic congenital nystagmus. Screening of 42 singleton cases of idiopathic congenital nystagmus (28 male, 14 females) yielded three mutations (7%). We found restricted expression of FRMD7 in human embryonic brain and developing neural retina, suggesting a specific role in the control of eye movement and gaze stability.

Ectodermal Dysplasia: A Clinical Overview for the Dental Practitioner.

The term ectodermal dysplasia (ED) is used to describe a group of rare congenital disorders characterized by abnormalities of two or more ectodermal structures such as the skin, hair, nails, teeth and sweat glands. This paper will give an overview of the aetiology of ED and describe the manifestations and dental management of this condition. In particular, the important role of the dental practitioner in the identification and management of patients with ED will be highlighted. CPD/Clinical Relevance: Dental practitioners should be aware of the oral features of ectodermal dysplasia and be able to make timely referrals and provide appropriate continuing care for these patients.