Noninvasive Method Using Mechanical Extensometer for the Estimation of Intracranial Compliance by Repeated Measures Agreement Analysis.

BACKGROUND: Intracranial compliance refers to the relationship between changes in volume and the resultant changes in intracranial pressure (ICP). This study aimed to assess the agreement of a noninvasive ICP waveform device for the estimation of compliance compared with invasive ICP monitoring employing three distinct methods. METHODS: We conducted a retrospective analysis of ICP waveform morphology recorded through both invasive (external ventricular drain) and noninvasive (mechanical extensometer) methods in adult patients with acute brain injury admitted to a neurointensive care unit between August 2021 and August 2022. Compliance was calculated as the amplitude of the fundamental component of cerebral arterial blood volume (estimated with concurrent Transcranial Doppler [TCD] recordings), divided by the amplitude of the fundamental component of the invasive and noninvasive ICP waveforms. Subsequently, we assessed the agreement between invasive and noninvasive intracranial compliance by repeated measures correlation coefficient analysis using three methods: TCD-derived, P2/P1 ratio, and time-to-peak (TTP). A linear mixed-effects model was used to compute the concordance correlation coefficient, total deviation index, and coefficient of individual agreement. Coverage probability plot was calculated to estimate the percent of observations within different cut points for each of the three methods. RESULTS: A total of 21 patients were identified for this study. Repeated measures correlation analysis showed a strong correlation (R = 0.982, 95% confidence interval [0.980-0.984], p < 0.0001) between log-transformed noninvasive and invasive compliance. Agreement statistics for TCD, P2/P1 ratio, and TTP indicated that although the concordance correlation coefficient was highest for log(TCD) values, TTP and P2:P1 ratio measures had better agreement with total deviation index and coverage probability plot analyses. CONCLUSIONS: Repeated measures correlations suggest that ICP waveform analyses may offer a more accurate estimate of compliance than TCD-derived methods for noninvasive ICP monitoring. Further validations studies are warranted to confidently establish this method as an indicator of intracranial compliance.

Effect of Exenatide Use on Cognitive and Affective Functioning in Obese Patients With Type 2 Diabetes Mellitus: Exenatide Use Mediates Depressive Scores Through Increased Perceived Stress Levels.

PURPOSE/BACKGROUND: Glucagon-like peptide-1 (GLP-1) is a molecule used to treat type 2 diabetes mellitus (T2DM). Given their widespread expression in the nervous system, GLP-1 receptors also play a role in regulating mood and cognitive function. Here, we aimed to compare obese patients with T2DM, with or without exenatide (a GLP-1R agonist) use on cognitive and affective functioning. METHODS/PROCEDURES: A total of 43 patients with T2DM (23 on exenatide and 20 without exenatide) were evaluated with the Snaith-Hamilton Pleasure Scale, Cognitive Failures Questionnaire, Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7, Childhood Trauma Questionnaire, Perceived Stress Scale (PSS), and Chronic Stress Scale, in addition to laboratory-based measures of reward learning (the probabilistic reward task) and working memory (Letter-N-Back task). FINDINGS/RESULTS: Patients on exenatide had higher body mass index (BMI) (37.88 ± 5.44 vs 35.29 ± 6.30; P = 0.015), PHQ-9 (9.70 ± 4.92 vs 6.70 ± 4.66; P = 0.026), and PSS (29.39 ± 6.70 vs 23.35 ± 7.69; P = 0.015) scores. Other stress scales (Childhood Trauma Questionnaire and Chronic Stress Scale), Generalized Anxiety Disorder-7 scores, response bias, or discriminability as assessed by probabilistic reward task and self-report (Cognitive Failures Questionnaire) and laboratory-based (Letter-N-Back) cognitive measures were not significantly different between groups (both Ps > 0.05). Multivariate linear regression analyses adding BMI and PSS as covariates revealed that although BMI had no effect (P = 0.5), PSS significantly predicted PHQ-9 scores (P = 0.004). Mediation analysis showed that exenatide users reported higher PSS, with greater PSS associated with higher PHQ-9 levels (b = 0.236). There was no evidence on exenatide directly influencing PHQ-9 independent of PSS (c' = 1.573; P = 0.305; 95% bootstrap confidence interval, -1.487 to 4.634). IMPLICATIONS/CONCLUSIONS: Based on previous research and our findings, exenatide use might be mediating depression scores through disrupting stress responses.

Tuberous sclerosis: a review of the past, present, and future

Tuberous sclerosis complex (TSC) is an autosomal dominant, multisystem disorder that is characterized by cellular and tissue dysplasia in several organs. With the advent of genetic and molecular techniques, mutations in the TSC1 or TSC2 genes were discovered to be responsible for mTOR overactivation, which is the underlying mechanism of pathogenesis. TSC is a highly heterogenous clinical entity with variable presentations and severity of disease. The brain, heart, skin, eyes, kidneys, and lungs are commonly involved in this syndrome, with neurologic symptoms comprising a significant source of morbidity and mortality. In 2012, the diagnostic criteria for TSC were revised by the International Tuberous Sclerosis Complex Consensus panel, and genetic testing was incorporated into the guidelines. Early detection of cardiac rhabdomyomas or TSC-associated skin lesions can suggest the diagnosis and underlie the importance of clinical vigilance. Animal studies have demonstrated the benefit of using mTOR inhibitors for various symptoms of TSC, and they have been successfully translated into clinical trials with significant improvement in symptom burden. Subependymal giant cell astrocytomas, renal angiomyolipomas, and epilepsy are the three FDA-approved indications in relation to TSC for the use of everolimus, which is a first generation mTOR inhibitor. Rapamycin has been FDA approved for lymphangioleiomyomatosis. Other TSC symptoms that could potentially benefit from this class of medication are currently under investigation. TSC constitutes a unique combination of protean physical symptoms and neurobehavioral abnormalities. TSC associated neuropsychiatric disorders (TAND), including intellectual disability, mood disorders, and autism spectrum disorder, represent significant challenges but remain underdiagnosed and undertreated. The TAND checklist is a useful tool for routine use in the clinical evaluation of TSC patients. A multidisciplinary treatment plan, based on the specific problems and needs of individuals, is the key to management of this genetic condition. Ongoing research studies have been providing promising leads for developing novel mechanistic strategies to address the pathophysiology of TSC.

Motor afferents from the cerebellum, zona incerta and substantia nigra to the mediodorsal thalamic nucleus in the rat.

The mediodorsal (MD) thalamic nucleus provides information from subcortical structures to the prefrontal cortex. The human MD thalamic nucleus has been implicated in a great variety of different clinical conditions and normal functions ranging from schizophrenia, Parkinsonism and epilepsy to many cognitive functions. In the rat the MD thalamic nucleus is divided into three cytoarchitectonic sectors whereas in the primates it is divided into two; medial one-third (magnocellular) and lateral two-thirds further the lateral sector is divided into pars parvocellularis pars multiformis, pars fasciculosa and pars caudalis. In this study we used a retrograde tracer, fluoro-gold (FG) to evaluate some of the afferents reaching the lateral sector of the MD (MDl) thalamic nucleus. The results of the present study have shown that MDl receives afferent connections from the lateral cerebellar nucleus (dentate nucleus), substantia nigra pars reticulata (SNR) and zona incerta (ZI). Subsequent to FG injections into the MDl, labeled cells were observed mainly bilaterally but were sparser on the contralateral side than ipsilaterally from each of the three structures listed. All three afferents showed a topographical organization. The labeled neurons were localized at the dorsomedial aspect of the lateral cerebellar nucleus, the dorsoventral aspect of the SNR and in the dorsal sector of the ZI. The lateral cerebellar nucleus reached the MDl via the superior cerebellar peduncle. No other deep cerebellar nuclei showed labeled cells. There were no labeled cells in the substantia nigra pars compacta (SNC). Although the three regions identified here are recognized as having motor functions, the connections to MD suggest that their outputs also play a role in cognitive or other higher cortical functions.

Promising therapies for the treatment of myasthenia gravis.

INTRODUCTION: Myasthenia gravis (MG) is an autoimmune condition targeting the neuromuscular junction, which manifests with neuromuscular symptoms of varying severity and significant morbidity. The mainstay of treatment in MG is mitigation of the immune cascade with steroids and non-steroidal immunosuppressive therapies. The therapeutic strategies in MG are transitioning from broad and indiscriminate immunosuppression to novel agents targeting key steps in MG pathogenesis, including T cell activation, B cell proliferation, complement activation, maintenance of pathogenic antibody production, and proinflammatory cytokine production. AREAS COVERED: In this review, an overview of the pathogenesis of MG and traditional MG therapies is presented, followed by a discussion of the novel MG drugs that have been evaluated in phase 3 clinical trials with an emphasis on those which have received regulatory approval. EXPERT OPINION: Novel MG therapeutics belonging to the classes of complement inhibitors, neonatal Fc receptor (FcRn) inhibitors and B cell depletors, as well as the other emerging MG drugs in the pipeline constitute promising treatment strategies with potentially better efficacy and safety compared to the conventional MG treatments. However, further long-term research is needed in order to optimize the implementation of these new treatment options for the appropriate patient populations.

A 52-Year-Old Man With Progressive Weakness and Incontinence.

Here we report a challenging case of a 52-year-old man presenting with subacute constipation, urinary retention, impotence, absent Achilles reflexes, and hypoesthesia in S2-S5 dermatomes. We review the clinical decision-making as the symptoms evolved and diagnostic testing changed over time. Once the diagnosis is settled, we discuss the sign and symptoms, additional diagnostic tools, treatment options and prognosis.

Pitfalls in the use of whole slide imaging for the diagnosis of central nervous system tumors: A pilot study in surgical neuropathology.

BACKGROUND: Whole slide imaging (WSI) finds increasingly higher value in everyday surgical pathology in addition to its well-established use for educational and research purposes. However, its diagnostic utility, especially in subspecialty settings such as neuropathology, is not fully validated. Neuropathology practice is unique with smaller overall tissue size and frequent need for high-power evaluation. In addition, tumor grade is an integral part of the initial diagnosis. The purpose of this study is to assess the feasibility of primary pathology diagnosis of surgical neuropathology specimens using WSI. MATERIALS AND METHODS: We reviewed consecutive surgical neuropathology cases diagnosed in our institution during a 2-month period and identified a single diagnostic slide, which was scanned at 40× magnification. Two neuropathologists who were blinded to the original diagnoses reviewed the whole slide image and rendered a diagnosis including tumor grade when applicable. They reviewed the single diagnostic slide after a wash-out period. Intra- and inter-observer discrepancies, as well as reasons for discrepancies, were evaluated. RESULTS: The concordance rates were 94.9% and 88% for two neuropathologists. Two critical issues leading to discrepancies were identified: (1) identification of mitoses and (2) recognition of nuclear details. CONCLUSIONS: Given the current study is exclusively for surgical neuropathology cases, an all-encompassing conclusion about the utility of WSI for diagnostic purposes may not be available. Nevertheless, pathologists should be aware of the potential pitfalls due to identification of mitotic figures and nuclear details. We recommend independent validation for each subspecialty of pathology to identify subspecialty-specific concerns, so they can be properly addressed.

Who can get the next Nobel Prize in infectious diseases?

The aim of this paper is to deliver a perspective on future Nobel prizes by reviewing the features of Nobel prizes awarded in the infectious diseases-related (IDR) field over the last 115 years. Thirty-three out of 106 Nobel prizes (31%) in Physiology or Medicine have been awarded for IDR topics. Out of 58 Nobel laureates for IDR topics, two have been female; 67% have been medical doctors. The median age of Nobel laureates in Physiology or Medicine was found to be lower than the median age of laureates in Literature (p<0.001). Since the Second World War, US-affiliated scientists have dominated the Nobel prizes (53%); however before 1945, German scientists did so (p=0.005). The new antimicrobials received Nobel prizes until 1960; however no treatment study was awarded the Prize until the discovery of artemisinin and ivermectin, for which the Nobel Prize was awarded in 2015. Collaborative works have increasingly been appreciated. In the future, more female laureates would be expected in the IDR field. Medical graduates and scientists involved in multi-institutional and multidisciplinary collaborative efforts seem to have an advantage.