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1.
EMBO Mol Med ; 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38831131

RESUMO

Achieving complete tumor resection is challenging and can be improved by real-time fluorescence-guided surgery with molecular-targeted probes. However, pre-clinical identification and validation of probes presents a lengthy process that is traditionally performed in animal models and further hampered by inter- and intra-tumoral heterogeneity in target expression. To screen multiple probes at patient scale, we developed a multispectral real-time 3D imaging platform that implements organoid technology to effectively model patient tumor heterogeneity and, importantly, healthy human tissue binding.

2.
Plant J ; 2024 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-38824612

RESUMO

DNA-protein crosslinks (DPCs) are highly toxic DNA lesions represented by proteins covalently bound to the DNA. Persisting DPCs interfere with fundamental genetic processes such as DNA replication and transcription. Cytidine analog zebularine (ZEB) has been shown to crosslink DNA METHYLTRANSFERASE1 (MET1). Recently, we uncovered a critical role of the SMC5/6-mediated SUMOylation in the repair of DPCs. In an ongoing genetic screen, we identified two additional candidates, HYPERSENSITIVE TO ZEBULARINE 2 and 3, that were mapped to REGULATOR OF TELOMERE ELONGATION 1 (RTEL1) and polymerase TEBICHI (TEB), respectively. By monitoring the growth of hze2 and hze3 plants in response to zebularine, we show the importance of homologous recombination (HR) factor RTEL1 and microhomology-mediated end-joining (MMEJ) polymerase TEB in the repair of MET1-DPCs. Moreover, genetic interaction and sensitivity assays showed the interdependency of SMC5/6 complex, HR, and MMEJ in the homology-directed repair of MET1-DPCs in Arabidopsis. Altogether, we provide evidence that MET1-DPC repair in plants is more complex than originally expected.

4.
Eur J Paediatr Neurol ; 51: 24-31, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38776696

RESUMO

BACKGROUND: Despite the established efficacy of glycopyrronium bromide in reducing drooling among children with neurodevelopmental disabilities, evidence on its impact on the daily lives of children and parents and effectiveness in a real-world setting are scarce, especially among long-term users. This study explored timing and duration of glycopyrronium treatment, effect and impact on daily life, and occurrence of side effects to inform clinical practice. METHODS: This was a retrospective cohort study at a national referral centre for drooling, including 61 children with nonprogressive neurodevelopmental disabilities, treated with glycopyrronium for anterior and/or posterior drooling between 2011 and 2021. Data were obtained from medical records and supplemented by structured telephone interviews with parents. RESULTS: Anterior drooling severity decreased in 82% of the included children. Changes in the impact of drooling on burden of care, social interaction, and self-esteem were reported in 55%, 31%, and 36%, respectively. Side effects were noted for 71% of cases, yet only 36% of parents deemed these as outweighing the positive impact of treatment. A substantial majority (77%) of the included children were long-term users (≥6 months). Among these, 38% of parents reported decreasing effectiveness and 27% noticed more prominent side effects over time. CONCLUSIONS: Glycopyrronium demonstrated potential in mitigating the impact of drooling on daily life, although variations were observed in the specific aspects and extent of improvement. The real-world context of our study provides important insights for refining clinical practices, emphasizing the need for balanced consideration of treatment benefits and potential side effects to facilitate shared decision-making.

5.
Eur J Psychotraumatol ; 15(1): 2341577, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38747113

RESUMO

Background: Literature points towards the potential benefits of the application of Eye Movement and Desensitization Processing (EMDR)-therapy for patients in the medical setting, with cancer and pain being among the domains it is applied to. The field of applying EMDR-therapy for patients treated in the medical setting has evolved to such an extent that it may be challenging to get a comprehensive overview.Objective: This systematic literature review aims to evaluate the use and effectiveness of Eye Movement Desensitization and Reprocessing (EMDR) therapy in patients treated in the medical setting.Methods: We performed a literature search following the PRISMA guidelines. Studies were included if the effectiveness of EMDR-therapy was assessed in adult patients treated in a medical setting. Excluded were patients exclusively suffering from a mental health disorder, without somatic comorbidity. A risk of bias analysis was performed. This review was registered on PROSPERO (CRD42022325238).Results: Eighty-seven studies, of which 26 (pilot)-RCTs were included and categorized in 14 medical domains. Additionally, three studies focusing on persistent physical complaints were included. Most evidence exists for its application in the fields of oncology, pain, and neurology. The overall appraisal of these studies showed at least moderate to high risks of bias. EMDR demonstrated effectiveness in reducing symptoms in 85 out of 87 studies. Notably, the occurrence of adverse events was rarely mentioned.Conclusions: Overall, outcomes seem to show beneficial effects of EMDR on reducing psychological and physical symptoms in patients treated in a medical setting. Due to the heterogeneity of reported outcomes, effect sizes could not be pooled. Due to the high risk of bias of the included studies, our results should be interpreted with caution and further controlled high-quality research is needed.


First overview on the use of EMDR for adult patients treated in the medical setting.EMDR seems beneficial in improving psychological and physical symptoms.Given the heterogeneity of studies and high risk of bias, further controlled studies are needed in this field.


Assuntos
Dessensibilização e Reprocessamento através dos Movimentos Oculares , Humanos , Neoplasias/terapia
7.
Open Biol ; 14(5): 240018, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38745463

RESUMO

The neuronal cell adhesion molecule contactin-4 (CNTN4) is genetically associated with autism spectrum disorder (ASD) and other psychiatric disorders. Cntn4-deficient mouse models have previously shown that CNTN4 plays important roles in axon guidance and synaptic plasticity in the hippocampus. However, the pathogenesis and functional role of CNTN4 in the cortex has not yet been investigated. Our study found a reduction in cortical thickness in the motor cortex of Cntn4 -/- mice, but cortical cell migration and differentiation were unaffected. Significant morphological changes were observed in neurons in the M1 region of the motor cortex, indicating that CNTN4 is also involved in the morphology and spine density of neurons in the motor cortex. Furthermore, mass spectrometry analysis identified an interaction partner for CNTN4, confirming an interaction between CNTN4 and amyloid-precursor protein (APP). Knockout human cells for CNTN4 and/or APP revealed a relationship between CNTN4 and APP. This study demonstrates that CNTN4 contributes to cortical development and that binding and interplay with APP controls neural elongation. This is an important finding for understanding the physiological function of APP, a key protein for Alzheimer's disease. The binding between CNTN4 and APP, which is involved in neurodevelopment, is essential for healthy nerve outgrowth.


Assuntos
Precursor de Proteína beta-Amiloide , Contactinas , Camundongos Knockout , Neurônios , Animais , Camundongos , Precursor de Proteína beta-Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/genética , Humanos , Contactinas/metabolismo , Contactinas/genética , Neurônios/metabolismo , Córtex Motor/metabolismo , Ligação Proteica , Movimento Celular
9.
Plant Mol Biol ; 114(3): 56, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38743198

RESUMO

Most eukaryotic organisms employ a telomerase complex for the maintenance of chromosome ends. The core of this complex is composed of telomerase reverse transcriptase (TERT) and telomerase RNA (TR) subunits. The TERT reverse transcriptase (RT) domain synthesises telomeric DNA using the TR template sequence. The other TERT domains contribute to this process in different ways. In particular, the TERT RNA-binding domain (TRBD) interacts with specific TR motif(s). Using a yeast 3-hybrid system, we show the critical role of Arabidopsis thaliana (At) TRBD and embryophyta-conserved KRxR motif in the unstructured linker preceding the TRBD domain for binding to the recently identified AtTR subunit. We also show the essential role of the predicted P4 stem and pseudoknot AtTR structures and provide evidence for the binding of AtTRBD to pseudoknot and KRxR motif stabilising interaction with the P4 stem structure. Our results thus provide the first insight into the core part of the plant telomerase complex.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Telomerase , Telomerase/genética , Telomerase/metabolismo , Telomerase/química , Arabidopsis/genética , Arabidopsis/enzimologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/química , RNA/metabolismo , RNA/genética , Técnicas do Sistema de Duplo-Híbrido , RNA de Plantas/genética , RNA de Plantas/metabolismo , Conformação de Ácido Nucleico , Ligação Proteica
12.
Inorg Chem ; 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38819111

RESUMO

Although numerous polyphosphido complexes have been accessed through the transition-metal-mediated activation and functionalization of white phosphorus (P4), the selective functionalization of the resulting polyphosphorus ligands in these compounds remains underdeveloped. In this study, we explore the reactions between cyclotetraphosphido cobalt complexes and heterocumulenes, leading to functionalized P4 ligands. Specifically, the reaction of carbon disulfide (CS2) with [K(18c-6)][(Ar*BIAN)Co(η4-P4)] ([K(18c-6)]1, 18c-6 = [18]crown-6) affords the adduct [K(18c-6)][(Ar*BIAN)Co(η3:η1-P4CS2)] ([K(18c-6)]3), in which CS2 is attached to a single phosphorus atom (Ar* = 2,6-dibenzhydryl-4-isopropylphenyl, BIAN = 1,2-bis(arylimino)acenaphthene diimine). In contrast, the insertion of bis(trimethylsilyl)sulfur diimide S(NSiMe3)2 into a P-P bond of [K(18c-6)]1 yields [K(18c-6)][(Ar*BIAN)Co(η3:η1-P4SN2(SiMe3)2)] (K(18c-6)]4). This salt further reacts with Me3SiCl to form [(Ar*BIAN)Co(η3:η1-P4SN2(SiMe3)3] (5), featuring a rare azatetraphosphole ligand. Moreover, treatment of the previously reported complex [(Ar*BIAN)Co(η3:η1-P4C(O)tBu)] (2) with isothiocyanates results in P-C bond insertion, yielding [(Ar*BIAN)Co(η3:η1-P4C(S)N(R)C(O)tBu)] (6a,b; R = Cy, Ph).

13.
Lancet Oncol ; 25(6): 779-789, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38701815

RESUMO

BACKGROUND: Numerous studies have shown that older women with endometrial cancer have a higher risk of recurrence and cancer-related death. However, it remains unclear whether older age is a causal prognostic factor, or whether other risk factors become increasingly common with age. We aimed to address this question with a unique multimethod study design using state-of-the-art statistical and causal inference techniques on datasets of three large, randomised trials. METHODS: In this multimethod analysis, data from 1801 women participating in the randomised PORTEC-1, PORTEC-2, and PORTEC-3 trials were used for statistical analyses and causal inference. The cohort included 714 patients with intermediate-risk endometrial cancer, 427 patients with high-intermediate risk endometrial cancer, and 660 patients with high-risk endometrial cancer. Associations of age with clinicopathological and molecular features were analysed using non-parametric tests. Multivariable competing risk analyses were performed to determine the independent prognostic value of age. To analyse age as a causal prognostic variable, a deep learning causal inference model called AutoCI was used. FINDINGS: Median follow-up as estimated using the reversed Kaplan-Meier method was 12·3 years (95% CI 11·9-12·6) for PORTEC-1, 10·5 years (10·2-10·7) for PORTEC-2, and 6·1 years (5·9-6·3) for PORTEC-3. Both overall recurrence and endometrial cancer-specific death significantly increased with age. Moreover, older women had a higher frequency of deep myometrial invasion, serous tumour histology, and p53-abnormal tumours. Age was an independent risk factor for both overall recurrence (hazard ratio [HR] 1·02 per year, 95% CI 1·01-1·04; p=0·0012) and endometrial cancer-specific death (HR 1·03 per year, 1·01-1·05; p=0·0012) and was identified as a significant causal variable. INTERPRETATION: This study showed that advanced age was associated with more aggressive tumour features in women with endometrial cancer, and was independently and causally related to worse oncological outcomes. Therefore, our findings suggest that older women with endometrial cancer should not be excluded from diagnostic assessments, molecular testing, and adjuvant therapy based on their age alone. FUNDING: None.


Assuntos
Neoplasias do Endométrio , Humanos , Feminino , Neoplasias do Endométrio/patologia , Neoplasias do Endométrio/mortalidade , Fatores Etários , Idoso , Pessoa de Meia-Idade , Prognóstico , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores de Risco , Recidiva Local de Neoplasia/patologia , Recidiva Local de Neoplasia/epidemiologia , Idoso de 80 Anos ou mais
14.
Blood ; 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38728380

RESUMO

In MDS patients higher IPSS-R at transplant is associated with worse transplant outcome. Thus, it may seem beneficial to improve IPSS-R by therapeutic intervention prior to transplantation in order to "down-stage" the disease risk. However, there is no evidence to date to support this approach. A retrospective analysis of the EBMT transplant registry was performed to investigate the role of therapeutic interventions prior to transplantation with regard to changes in IPSS-R and transplant outcomes. A total of 1482 MDS patients with sufficient data to calculate IPSS-R at diagnosis and at time of transplantation were selected and analysed for transplant outcome in a multivariable Cox model including IPSS-R at diagnosis, treatment intervention, change in IPSS-R before transplant and several patient and transplant variables. Transplant outcome was unaffected by IPSS-R change in untreated patients and moderately superior in chemotherapy-treated patients with improved IPSS-R at transplant. Improved IPSS-R after hypomethylating agents (HMA) or other therapies showed no beneficial effect. However, when IPSS-R progressed after chemotherapy, (HMA) or other therapies, transplant outcome was worse than without any prior treatment. Similar results were found when reduction or increase in bone marrow (BM) blasts between diagnosis and transplantation was considered. The results show a limited benefit of IPSS-R down staging or reduction of BM blasts after chemotherapy and no benefit for HMA or other treatments and thus question the role of prior therapy in MDS patients scheduled for transplantation. The model-based survival estimates should help inform decision making for both doctors and patients.

15.
BMC Vet Res ; 20(1): 188, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38730373

RESUMO

Femoral fractures are often considered lethal for adult horses because femur osteosynthesis is still a surgical challenge. For equine femur osteosynthesis, primary stability is essential, but the detailed physiological forces occurring in the hindlimb are largely unknown. The objective of this study was to create a numerical testing environment to evaluate equine femur osteosynthesis based on physiological conditions. The study was designed as a finite element analysis (FEA) of the femur using a musculoskeletal model of the loading situation in stance. Relevant forces were determined in the musculoskeletal model via optimization. The treatment of four different fracture types with an intramedullary nail was investigated in FEA with loading conditions derived from the model. The analyzed diaphyseal fracture types were a transverse (TR) fracture, two oblique fractures in different orientations (OB-ML: medial-lateral and OB-AP: anterior-posterior) and a "gap" fracture (GAP) without contact between the fragments. For the native femur, the most relevant areas of increased stress were located distally to the femoral head and proximally to the caudal side of the condyles. For all fracture types, the highest stresses in the implant material were present in the fracture-adjacent screws. Maximum compressive (-348 MPa) and tensile stress (197 MPa) were found for the GAP fracture, but material strength was not exceeded. The mathematical model was able to predict a load distribution in the femur of the standing horse and was used to assess the performance of internal fixation devices via FEA. The analyzed intramedullary nail and screws showed sufficient stability for all fracture types.


Assuntos
Fraturas do Fêmur , Fixação Interna de Fraturas , Membro Posterior , Animais , Cavalos/fisiologia , Fenômenos Biomecânicos , Fraturas do Fêmur/veterinária , Fraturas do Fêmur/cirurgia , Fixação Interna de Fraturas/veterinária , Fixação Interna de Fraturas/métodos , Membro Posterior/cirurgia , Análise de Elementos Finitos , Fêmur/cirurgia , Modelos Biológicos , Suporte de Carga , Fixação Intramedular de Fraturas/veterinária , Fixação Intramedular de Fraturas/instrumentação
16.
Artigo em Inglês | MEDLINE | ID: mdl-38763170

RESUMO

BACKGROUND: Despite impaired humoral responses in patients treated with immunosuppressants (ISPs), recent studies found similar severity of SARS-CoV-2 breakthrough infections compared to controls. One potential explanation is the rapid generation humoral responses upon infection, but evidence is lacking. OBJECTIVES: To investigate longitudinal dynamics of the SARS-CoV-2 antibody repertoire after SARS-CoV-2 delta and omicron breakthrough infections in patients with immune-mediated inflammatory diseases (IMID) on ISPs and controls. METHODS: As prospective sub-study of the national Target-to-B! (T2B!) consortium, we included IMID patients on ISPs and controls who reported SARS-CoV-2 breakthrough infections between July 1, 2021, and April 1, 2022. To get an impression of the dynamics of the antibody repertoire, three antibody titers of wild-type RBD, wild-type S, and omicron RBD were measured at four time points after SARS-CoV-2 breakthrough infections. RESULTS: We included 302 IMID patients on ISPs and 178 controls. Antibody titers increased up to 28 days after breakthrough infections in both groups. However, in IMID patients on anti-CD20 therapy and sphingosine-1 phosphate receptor (S1P) modulators, antibody titers were considerably lower compared to controls. In the anti-TNF group, we observed slightly lower antibody titers in the early stages and a faster decline of antibodies after infection compared to controls. Breakthrough infections were mostly mild and hospitalization was required in less than 1% of the cases. CONCLUSIONS: Most ISPs do not influence the dynamics of the SARS-CoV-2 antibody repertoire and exhibit a rapid recall response with cross-reactive antibody clones towards new viral variants. However, in patients treated with anti-CD20 therapy or S1P modulators, the dynamics were greatly impaired, and to a lesser extent in those anti-TNF. Nevertheless, only a few severe breakthrough cases were reported.

17.
Nat Med ; 2024 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-38789645

RESUMO

Predicting distant recurrence of endometrial cancer (EC) is crucial for personalized adjuvant treatment. The current gold standard of combined pathological and molecular profiling is costly, hampering implementation. Here we developed HECTOR (histopathology-based endometrial cancer tailored outcome risk), a multimodal deep learning prognostic model using hematoxylin and eosin-stained, whole-slide images and tumor stage as input, on 2,072 patients from eight EC cohorts including the PORTEC-1/-2/-3 randomized trials. HECTOR demonstrated C-indices in internal (n = 353) and two external (n = 160 and n = 151) test sets of 0.789, 0.828 and 0.815, respectively, outperforming the current gold standard, and identified patients with markedly different outcomes (10-year distant recurrence-free probabilities of 97.0%, 77.7% and 58.1% for HECTOR low-, intermediate- and high-risk groups, respectively, by Kaplan-Meier analysis). HECTOR also predicted adjuvant chemotherapy benefit better than current methods. Morphological and genomic feature extraction identified correlates of HECTOR risk groups, some with therapeutic potential. HECTOR improves on the current gold standard and may help delivery of personalized treatment in EC.

18.
Ann Intensive Care ; 14(1): 77, 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38771395

RESUMO

PURPOSE: To identify key components and variations in family-centered care practices. METHODS: A cross-sectional study, conducted across ESICM members. Participating ICUs completed a questionnaire covering general ICU characteristics, visitation policies, team-family interactions, and end-of-life decision-making. The primary outcome, self-rated family-centeredness, was assessed using a visual analog scale. Additionally, respondents completed the Maslach Burnout Inventory and the Ethical Decision Making Climate Questionnaire to capture burnout dimensions and assess the ethical decision-making climate. RESULTS: The response rate was 53% (respondents from 359/683 invited ICUs who actually open the email); participating healthcare professionals (HCPs) were from Europe (62%), Asia (9%), South America (6%), North America (5%), Middle East (4%), and Australia/New Zealand (4%). The importance of family-centeredness was ranked high, median 7 (IQR 6-8) of 10 on VAS. Significant differences were observed across quartiles of family centeredness, including in visitation policies availability of a waiting rooms, family rooms, family information leaflet, visiting hours, night visits, sleep in the ICU, and in team-family interactions, including daily information, routine day-3 conference, and willingness to empower nurses and relatives. Higher family centeredness correlated with family involvement in rounds, participation in patient care and end-of-life practices. Burnout symptoms (41% of respondents) were negatively associated with family-centeredness. Ethical climate and willingness to empower nurses were independent predictors of family centeredness. CONCLUSIONS: This study emphasizes the need to prioritize healthcare providers' mental health for enhanced family-centered care. Further research is warranted to assess the impact of improving the ethical climate on family-centeredness.

19.
Br J Surg ; 111(5)2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38721902

RESUMO

OBJECTIVE: Locally advanced oesophageal squamous cell carcinoma can be treated with neoadjuvant chemoradiotherapy or chemotherapy followed by oesophagectomy. Discrepancies in pathological response rates have been reported between studies from Eastern versus Western countries. The aim of this study was to compare the pathological response to neoadjuvant chemoradiotherapy in Eastern versus Western countries. METHODS: Databases were searched until November 2022 for studies reporting pCR rates after neoadjuvant chemoradiotherapy for oesophageal squamous cell carcinoma. Multi-level meta-analyses were performed to pool pCR rates separately for cohorts from studies performed in centres in the Sinosphere (East) or in Europe and the Anglosphere (West). RESULTS: For neoadjuvant chemoradiotherapy, 51 Eastern cohorts (5636 patients) and 20 Western cohorts (3039 patients) were included. Studies from Eastern countries included more men, younger patients, more proximal tumours, and more cT4 and cN+ disease. Patients in the West were more often treated with high-dose radiotherapy, whereas patients in the East were more often treated with a platinum + fluoropyrimidine regimen. The pooled pCR rate after neoadjuvant chemoradiotherapy was 31.7% (95% c.i. 29.5% to 34.1%) in Eastern cohorts versus 40.4% (95% c.i. 35.0% to 45.9%) in Western cohorts (fixed-effect P = 0.003). For cohorts with similar cTNM stages, pooled pCR rates for the East and the West were 32.5% and 41.9% respectively (fixed-effect P = 0.003). CONCLUSION: The pathological response to neoadjuvant chemoradiotherapy is less favourable in patients treated in Eastern countries compared with Western countries. Despite efforts to investigate accounting factors, the discrepancy in pCR rate cannot be entirely explained by differences in patient, tumour, or treatment characteristics.


Assuntos
Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Terapia Neoadjuvante , Humanos , Neoplasias Esofágicas/terapia , Neoplasias Esofágicas/patologia , Carcinoma de Células Escamosas do Esôfago/terapia , Carcinoma de Células Escamosas do Esôfago/patologia , Esofagectomia , Quimiorradioterapia Adjuvante , Quimiorradioterapia , Europa (Continente) , Resultado do Tratamento
20.
Eur J Neurosci ; 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38650308

RESUMO

Muscle-specific kinase myasthenia gravis (MuSK MG) is caused by autoantibodies against MuSK in the neuromuscular junction (NMJ). MuSK MG patients have fluctuating, fatigable skeletal muscle weakness, in particular of bulbar muscles. Severity differs greatly between patients, in spite of comparable autoantibody levels. One explanation for inter-patient and inter-muscle variability in sensitivity might be variations in compensatory muscle responses. Previously, we developed a passive transfer mouse model for MuSK MG. In preliminary ex vivo experiments, we observed that muscle contraction of some mice, in particular those with milder myasthenia, had become partially insensitive to inhibition by µ-Conotoxin-GIIIB, a blocker of skeletal muscle NaV1.4 voltage-gated sodium channels. We hypothesised that changes in NaV channel expression profile, possibly co-expression of (µ-Conotoxin-GIIIB insensitive) NaV1.5 type channels, might lower the muscle fibre's firing threshold and facilitate neuromuscular synaptic transmission. To test this hypothesis, we here performed passive transfer in immuno-compromised mice, using 'high', 'intermediate' and 'low' dosing regimens of purified MuSK MG patient IgG4. We compared myasthenia levels, µ-Conotoxin-GIIIB resistance and muscle fibre action potential characteristics and firing thresholds. High- and intermediate-dosed mice showed clear, progressive myasthenia, not seen in low-dosed animals. However, diaphragm NMJ electrophysiology demonstrated almost equal myasthenic severities amongst all regimens. Nonetheless, low-dosed mouse diaphragms showed a much higher degree of µ-Conotoxin-GIIIB resistance. This was not explained by upregulation of Scn5a (the NaV1.5 gene), lowered muscle fibre firing thresholds or histologically detectable upregulated NaV1.5 channels. It remains to be established which factors are responsible for the observed µ-Conotoxin-GIIIB insensitivity and whether the NaV repertoire change is compensatory beneficial or a bystander effect.

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