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13 result(s) for "Leibowitz, Maya"
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The spectral sensitivity of Drosophila photoreceptors
Drosophila melanogaster has long been a popular model insect species, due in large part to the availability of genetic tools and is fast becoming the model for insect colour vision. Key to understanding colour reception in Drosophila is in-depth knowledge of spectral inputs and downstream neural processing. While recent studies have sparked renewed interest in colour processing in Drosophila , photoreceptor spectral sensitivity measurements have yet to be carried out in vivo. We have fully characterised the spectral input to the motion and colour vision pathways, and directly measured the effects of spectral modulating factors, screening pigment density and carotenoid-based ocular pigments. All receptor sensitivities had significant shifts in spectral sensitivity compared to previous measurements. Notably, the spectral range of the Rh6 visual pigment is substantially broadened and its peak sensitivity is shifted by 92 nm from 508 to 600 nm. We show that this deviation can be explained by transmission of long wavelengths through the red screening pigment and by the presence of the blue-absorbing filter in the R7y receptors. Further, we tested direct interactions between inner and outer photoreceptors using selective recovery of activity in photoreceptor pairs.
Falsely low glycosylated haemoglobin levels probably secondary to hypersplenism in a patient with diabetes mellitus
A man in his 70s presented with a history of low glycated haemoglobin (HbA1c) values despite a diagnosis of type 2 diabetes. His blood glucose readings ranged between 8 and 15 mmol/L, but his HbA1c values were below 27 mmol/mol. Initial investigations demonstrated evidence of reduced red blood cell lifespan as a cause of misleadingly low HbA1c values. Further investigation revealed chronic liver disease and splenomegaly, with hypersplenism being the probable cause of increased red blood cell turnover. HbA1c estimation was no longer reliable, so ongoing diabetic care was guided by home capillary blood glucose monitoring. Healthcare providers and clinical laboratorians need to be aware of the possible clinical implications of very low HbA1c values in patients with type 2 diabetes.
Osmotic gradient ektacytometry – a novel diagnostic approach for neuroacanthocytosis syndromes
The unique red blood cell (RBC) properties that characterize the rare neuroacanthocytosis syndromes (NAS) have prompted the exploration of osmotic gradient ektacytometry (Osmoscan) as a diagnostic tool for these disorders. In this exploratory study, we assessed if Osmoscans can discriminate NAS from other neurodegenerative diseases. A comprehensive assessment was conducted using Osmoscan on a diverse group of patients, including healthy controls (  = 9), neuroacanthocytosis syndrome patients (  = 6, 2 VPS13A and 4 XK disease), Parkinson's disease patients (  = 6), Huntington's disease patients (n = 5), and amyotrophic lateral sclerosis patients (  = 4). Concurrently, we collected and analyzed RBC indices and patients' characteristics. Statistically significant changes were observed in NAS patients compared to healthy controls and other conditions, specifically in osmolality at minimal elongation index (O ), maximal elongation index (EI ), the osmolality at half maximal elongation index in the hyperosmotic part of the curve (O ), and the width of the curve close to the osmolality at maximal elongation index (O -width). This study represents an initial exploration of RBC properties from NAS patients using osmotic gradient ektacytometry. While specific parameters exhibited differences, only O and O -width yielded 100% specificity for other neurodegenerative diseases. Moreover, unique correlations between Osmoscan parameters and RBC indices in NAS versus controls were identified, such as osmolality at maximal elongation index (O ) vs. mean cellular hemoglobin content (MCH) and minimal elongation index (EI ) vs. red blood cell distribution width (RDW). Given the limited sample size, further studies are essential to establish diagnostic guidelines based on these findings.
The ABILHAND-23 Patient Reported Outcome Measure in Secondary Progressive Multiple Sclerosis: A Cross-Sectional Analysis With the Nine Hole Peg Test
People with progressive multiple sclerosis (pwPMS), who typically have established lower limb dysfunction, experience greater disability from upper limb dysfunction (ULD). The 9-hole peg test (9HPT) is the primary clinical measure for ULD but does not fully capture the patient experience. The ABILHAND-23 is a well-validated patient-reported outcome measure (PROM) that evaluates bimanual ability in daily function. However, no large-scale studies have assessed if the 9HPT reflects the individual ULD experience in pwPMS. We sought to (van Munster et al. 2023) assess the associations between the ABILHAND-23 and 9HPT, and (Huertas-Hoyas et al. 2020) to assess the ability of the 9HPT and other relevant covariables to predict ABILHAND-23 scores, using baseline data from the MS-STAT2 trial, a phase 3 study on simvastatin for secondary progressive MS (SPMS). A cross-sectional analysis of baseline data from the UCLH cohort of the MS-STAT2 trial was performed using multiple linear regression to predict ABILHAND-23 logit scores by 9HPT. 225 participants were analyzed. ABILHAND-23 scores moderately correlated with the 9HPT (rho = 0.47). Regression analysis showed that better 9HPT performance modestly predicted ABILHAND-23 logits (β = -0.05, SE 0.008, p-value < 0.001). The 9HPT only modestly predicts the ABILHAND-23 but does not fully capture the individual's daily disability experience, underscoring the value of patient-reported outcome measures (PROMs) like the ABILHAND-23 in clinical trials.
Hashimoto's encephalitis - A case report
A 50 year-old woman with a background of focal epilepsy presented to Emergency Department (ED) in convulsive status epilepticus. After 1 year seizure-free on levetiracetam,she initially presented with headache, tremor, fatigue and general malaise. She was discharged, then re-presented to ED several days later in status epilepticus. Two doses of diazepam administered pre-hospital failed to terminate the seizure. She was loaded with phenytoin,intubated and ventilated and commenced on a midazolam infusion. She spent 7 days in neuro-intensive care and was discharged home on levetiracetam 1.5 g twice daily and phyentoin 250 mg twice daily. One month later, she re-presented to ED with 4 days of worsening tremors and reduced mobility. Physical examination revealed multifocal myoclonus. She had experienced significant cognitive decline and neuropsychiatric symptoms including severe anxiety, delusions and paranoia. Investigations Imaging Initial MRI head with gadolinium showed marked symmetric abnormality within the white matter of both hemispheres extending into subcorticol regions, most predominant at the vertex and involving U fibres. The neuro-radiologist commented that the differential for these changes was broad, including an encephalitis, PML, meningitis or a leukoencephalopathy. Repeat MRI head 1 month later showed complete resolution of the white matter changes leaving no sequelae. Blood tests Her past medical history included subclinical hypothyroidism. Thyroid function tests showed an elevated TSH of 21.33 and thyroid peroxidase(TPO) antibody level of 188.0 IU/mL, with FT4 levels within normal range. Extensive relevant blood screen, including the following was all negative • NMDA, glycine receptor and anti-cardiolipin antibody • Connective tissue screen, anti-MPO and anti-PR3 • Serum electrophoresis • Paraneoplastic antibody screen including Cerebellum IIF, MA2, MA1, amphiphysin, CV2(CRMP5), Anti-Ri (ANNA 2) Ab, Anti Yo Ab and Anti Hu Ab • HIV and syphilis serology • JC virus • Plasma amino acid, urine organic acid and ammonia Lumbar puncture CSF WCC 1/mm3 CSF protein- 816 mg/L CSF viral PCR (including JC virus) and oligoclonal bands negative EEG- normal background activity with no clear focal or diagnostic epileptiform abnormalities. Treatment and follow-up The clinical picture, elevated TPO antibodies and absence of other relevant investigation abnormality raised Hashimoto's encephalitis as a potential unifying diagnosis. She had a good response to inpatient treatment with steroids, her neuropsychiatric features resolved and she has remained seizure-free since discharge. She remains under neurology outpatient follow-up. Discussion: It can be challenging to make a diagnosis of Hashimoto encephalitis, and other potential causes such as infection, metabolic or paraneoplastic processes must be rigorously ruled out (1). In this case, high titres of TPO alongside the clinical presentation with recurrent seizures and cognitive decline were key in making the diagnosis (2,3). Due to an overlap of features, including myoclonus and rapid cognitive decline, it was important to consider Creutzfeldt-Jakob disease (CJD) in the differential. We ruled out CJD due to the rapid response to steroid therapy and lack of typical EEG and MRI findings (4). Overall, due to low prevalence and non-specific MRI and EEG features, this diagnosis can be difficult to make and requires thorough systemic clinical assessment.
Transient Thyroiditis Followed by Exacerbation of Hypothyroidism After Immune Checkpoint Inhibitor Therapy (Nivolumab and Ipilimumab) in a Patient With Pre-existing Autoimmune Hypothyroidism: A Case Report
Treatment with immune checkpoint inhibitors has improved the prognosis of solid tumors. However, immune-related adverse events (IRAEs), including exacerbation of pre-existing autoimmune disease, are common and have become more frequent with combination therapy. The literature is scanty regarding reports of the use of combination immune checkpoint therapy in patients with pre-existing autoimmune hypothyroidism. We report a case of a man with a history of hypothyroidism, who developed transient thyroiditis, characterized by a thyrotoxic phase followed by a severe hypothyroid phase soon after receiving combination therapy (nivolumab and ipilimumab) for the treatment of a malignant pleural mesothelioma. He had been on a stable low dose of levothyroxine for 12 years prior to this episode. His levothyroxine requirement markedly increased soon after the episode of immune checkpoint inhibitor-induced thyroiditis. Immune checkpoint inhibitors can cause destructive thyroiditis followed by exacerbation of hypothyroidism in patients with pre-existing autoimmune hypothyroidism, such that patients end up on a higher dose of levothyroxine. This case will add to the growing literature regarding thyroid IRAEs associated with the use of immune checkpoint inhibitors in patients with pre-existing autoimmune thyroid disease.
The spectral sensitivity of Drosophila photoreceptors
Drosophila melanogaster has long been a popular model insect species, due in large part to the availability of genetic tools and is fast becoming the model for insect colour vision. Key to understanding colour reception in Drosophila is in-depth knowledge of spectral inputs and downstream neural processing. While recent studies have sparked renewed interest in colour processing in Drosophila, photoreceptor spectral sensitivity measurements have yet to be carried out in vivo. We have fully characterised the spectral input to the motion and colour vision pathways, and directly measured the effects of spectral modulating factors, screening pigment density and carotenoid-based ocular pigments. All receptor sensitivities had significant shifts in spectral sensitivity compared to previous measurements. Notably, the spectral range of the Rh6 visual pigment is substantially broadened and its peak sensitivity is shifted by 92 nm from 508 to 600 nm. We propose that this deviation can be explained by transmission of long wavelengths through the red screening pigment and by the presence of the blue-absorbing filter in the R7y receptors. Further, we tested direct interactions between photoreceptors and found evidence of interactions between inner and outer receptors, in agreement with previous findings of cross-modulation between receptor outputs in the lamina.
Biological insights from plasma proteomics of non-small cell lung cancer patients treated with immunotherapy
Immune checkpoint inhibitors have made a paradigm shift in the treatment of non-small cell lung cancer (NSCLC). However, clinical response varies widely and robust predictive biomarkers for patient stratification are lacking. Here, we characterize early on-treatment proteomic changes in blood plasma to gain a better understanding of treatment response and resistance. Pre-treatment (T0) and on-treatment (T1) plasma samples were collected from 225 NSCLC patients receiving PD-1/PD-L1 inhibitor-based regimens. Plasma was profiled using aptamer-based technology to quantify approximately 7000 plasma proteins per sample. Proteins displaying significant fold changes (T1:T0) were analyzed further to identify associations with clinical outcomes using clinical benefit and overall survival as endpoints. Bioinformatic analyses of upregulated proteins were performed to determine potential cell origins and enriched biological processes. The levels of 142 proteins were significantly increased in the plasma of NSCLC patients following ICI-based treatments. Soluble PD-1 exhibited the highest increase, with a positive correlation to tumor PD-L1 status, and, in the ICI monotherapy dataset, an association with improved overall survival. Bioinformatic analysis of the ICI monotherapy dataset revealed a set of 30 upregulated proteins that formed a single, highly interconnected network, including CD8A connected to ten other proteins, suggestive of T cell activation during ICI treatment. Notably, the T cell-related network was detected regardless of clinical benefit. Lastly, circulating proteins of alveolar origin were identified as potential biomarkers of limited clinical benefit, possibly due to a link with cellular stress and lung damage. Our study provides insights into the biological processes activated during ICI-based therapy, highlighting the potential of plasma proteomics to identify mechanisms of therapy resistance and biomarkers for outcome.
Foam cell‐derived 4‐hydroxynonenal induces endothelial cell senescence in a TXNIP‐dependent manner
Vascular endothelial cell (VEC) senescence is considered an early event in the development of atherosclerotic lesions. Stressful stimuli, in particular oxidative stress, have been linked to premature senescence in the vasculature. Foam cells are a major source of reactive oxygen species and may play a role in the induction of VEC senescence; hence, we investigated their involvement in the induction of VEC senescence in a co‐culture transwell system. Primary bovine aortic endothelial cells, exposed to the secretome of THP‐1 monocyte‐derived foam cells, were analysed for the induction of senescence. Senescence associated β‐galactosidase activity and the expression of p16 and p21 were increased, whereas phosphorylated retinoblastoma protein was reduced. This senescent phenotype was mediated by 4‐hydroxnonenal (4‐HNE), a lipid peroxidation product secreted from foam cells; scavenging of 4‐HNE in the co‐culture medium blunted this effect. Furthermore, both foam cells and 4‐HNE increased the expression of the pro‐oxidant thioredoxin‐interacting protein (TXNIP). Molecular manipulation of TXNIP expression confirmed its involvement in foam cell‐induced senescence. Previous studies showed that peroxisome proliferator‐activated receptor (PPAR)δ was activated by 4‐hydroalkenals, such as 4‐HNE. Pharmacological interventions supported the involvement of the 4‐HNE‐PPARδ axis in the induction of TXNIP and VEC senescence. The association of TXNIP with VEC senescence was further supported by immunofluorescent staining of human carotid plaques in which the expression of both TXNIP and p21 was augmented in endothelial cells. Collectively, these findings suggest that foam cell‐released 4‐HNE activates PPARδ in VEC, leading to increased TXNIP expression and consequently to senescence.
Assessing the Usability of a Novel Wearable Remote Patient Monitoring Device for the Early Detection of In-Hospital Patient Deterioration: Observational Study
Patients admitted to general wards are inherently at risk of deterioration. Thus, tools that can provide early detection of deterioration may be lifesaving. Frequent remote patient monitoring (RPM) has the potential to allow such early detection, leading to a timely intervention by health care providers. This study aimed to assess the potential of a novel wearable RPM device to provide timely alerts in patients at high risk for deterioration. This prospective observational study was conducted in two general wards of a large tertiary medical center. Patients determined to be at high risk to deteriorate upon admission and assigned to a telemetry bed were included. On top of the standard monitoring equipment, a wearable monitor was attached to each patient, and monitoring was conducted in parallel. The data gathered by the wearable monitors were analyzed retrospectively, with the medical staff being blinded to them in real time. Several early warning scores of the risk for deterioration were used, all calculated from frequent data collected by the wearable RPM device: these included (1) the National Early Warning Score (NEWS), (2) Airway, Breathing, Circulation, Neurology, and Other (ABCNO) score, and (3) deterioration criteria defined by the clinical team as a \"wish list\" score. In all three systems, the risk scores were calculated every 5 minutes using the data frequently collected by the wearable RPM device. Data generated by the early warning scores were compared with those obtained from the clinical records of actual deterioration among these patients. In total, 410 patients were recruited and 217 were included in the final analysis. The median age was 71 (IQR 62-78) years and 130 (59.9%) of them were male. Actual clinical deterioration occurred in 24 patients. The NEWS indicated high alert in 16 of these 24 (67%) patients, preceding actual clinical deterioration by 29 hours on average. The ABCNO score indicated high alert in 18 (75%) of these patients, preceding actual clinical deterioration by 38 hours on average. Early warning based on wish list scoring criteria was observed for all 24 patients 40 hours on average before clinical deterioration was detected by the medical staff. Importantly, early warning based on the wish list scoring criteria was also observed among all other patients who did not deteriorate. Frequent remote patient monitoring has the potential for early detection of a high risk to deteriorate among hospitalized patients, using both grouped signal-based scores and algorithm-based prediction. In this study, we show the ability to formulate scores for early warning by using RPM. Nevertheless, early warning scores compiled on the basis of these data failed to deliver reasonable specificity. Further efforts should be directed at improving the specificity and sensitivity of such tools. ClinicalTrials.gov NCT04220359; https://clinicaltrials.gov/ct2/show/NCT04220359.