Effects of storage conditions on the performance of an electrochemical aptamer-based sensor.

The electrochemical aptamer-based (EAB) sensor platform is the only molecular monitoring approach yet reported that is (1) real time and effectively continuous, (2) selective enough to deploy in situ in the living body, and (3) independent of the chemical or enzymatic reactivity of its target, rendering it adaptable to a wide range of analytes. These attributes suggest the EAB platform will prove to be an important tool in both biomedical research and clinical practice. To advance this possibility, here we have explored the stability of EAB sensors upon storage, using retention of the target recognizing aptamer, the sensor's signal gain, and the affinity of the aptamer as our performance metrics. Doing so we find that low-temperature (-20 °C) storage is sufficient to preserve sensor functionality for at least six months without the need for exogenous preservatives.

The BioPro Thumb Carpometacarpal Hemiarthroplasty: Case Series and Surgical Technique.

Thumb carpometacarpal (CMC) osteoarthritis is painful and debilitating. Here, we explore outcomes of a modular, press-fit thumb CMC hemiarthroplasty prosthesis (BioPro). This surgical option permits minimal bone resection, sparing the trapezium, hence allowing revision options if necessary. A retrospective review of all cases of the modular thumb CMC implants performed at one community US center between 2018 and 2021 were included and invited for email or telephone review. Electronic records were examined for demographics, patient outcomes, and morbidity. Eleven patients underwent 11 thumb CMC joint hemiarthroplasties, mean age was 64.8 years (SD: 7.68 y), with 6 females. Six received surgery on their dominant extremity. Two were manual workers (both in the medical field), 6 office-based, 2 retired, and 1 homemaker. The preoperative median pain score (Visual Analog Score) was 8/10 (range: 5 to 10), reducing to 1/10 (range: 1 to 10) ( P =0.000033) with a median follow-up of 23 months (range: 13 to 39 mo). In all, 8/11 patients reported they would recommend this surgery to friends and family and opt for the same surgery on their contralateral hand if necessary. One patient reported persistent pain a year postoperatively. On review, the head of the implant was placed too deep into the trapezium. Another center found that this patient had a postoperative trapezium fracture and underwent revision with implant removal and conversion to a suspension arthroplasty. At 12 months, 10/11 thumb CMC hemiarthroplasty showed good pain relief, function, and patient satisfaction. The BioPro has a low risk of subluxation and allows salvage options to remain available should failure occur.

Precise Electrochemical Sizing of Individual Electro-Inactive Particles.

Nanoimpact electrochemistry enables the time-resolved in situ characterization (e.g., size, catalytic activity) of single nanomaterial units, providing a means of elucidating heterogeneities that would be masked in ensemble studies. To implement this technique with redox inactive particles, a solution-phase redox reaction is used to produce a steady-state background current on a disk ultramicroelectrode. When a particle adsorbs onto the electrode, it produces a stepwise reduction in the exposed electrode area, which produces, in turn, a stepwise decrease in the current commensurate with the size of the adsorbing species. Historically, however, nanoimpact electrochemistry has suffered from "edge effects," in which the radial diffusion layer formed at the circumference of the ultramicroelectrodes renders the step size dependent not only on the size of the particle but also on where it lands on the electrode. The introduction of electrocatalytic current generation, however, mitigates the heterogeneity caused by edge effects, thus improving the measurement precision. In this approach, termed "electrocatalytic interruption," a substrate that regenerates the redox probe at the diffusion layer is introduced. This shifts the rate-limiting step of the current generation from diffusion to the homogeneous reaction rate constant, thus reducing flux heterogeneity and increasing the precision of particle sizing by an order of magnitude. The protocol described here explains the set-up and data collection employed in nanoimpact experiments implementing this effect for improved precision in the sizing of redox in-active materials.

On the Disinfection of Electrochemical Aptamer-Based Sensors.

Electrochemical aptamer-based (EAB) sensors encompass the only biosensor approach yet reported that is simultaneously: (1) independent of the chemical or enzymatic reactivity of its target, rendering it general; (2) continuous and real-time; and (3) selective enough to deploy in situ in the living body. Consistent with this, in vivo EAB sensors supporting the seconds-resolved, real-time measurement of multiple drugs and metabolites have been reported, suggesting the approach may prove of value in biomedical research and the diagnosis, treatment, and monitoring of disease. However, to apply these devices in long-duration animal models, much less in human patients, requires that they be free of any significant pathogen load. Thus motivated, here we have characterized the compatibility of EAB sensors with standard sterilization and high-level disinfection techniques. Doing so, we find that, while many lead to significant sensor degradation, treatment with CIDEX OPA (0.55% ortho-phthalaldehyde) leads to effective disinfection without causing any detectable loss in sensor performance.

Catalytic Interruption Mitigates Edge Effects in the Characterization of Heterogeneous, Insulating Nanoparticles.

Blocking electrochemistry, a subfield of nanochemistry, enables nondestructive, in situ measurement of the concentration, size, and size heterogeneity of highly dilute, nanometer-scale materials. This approach, in which the adsorptive impact of individual particles on a microelectrode prevents charge exchange with a freely diffusing electroactive redox mediator, has expanded the scope of electrochemistry to the study of redox-inert materials. A limitation, however, remains: inhomogeneous current fluxes associated with enhanced mass transfer occurring at the edges of planar microelectrodes confound the relationship between the size of the impacting particle and the signal it generates. These "edge effects" lead to the overestimation of size heterogeneity and, thus, poor sample characterization. In response, we demonstrate here the ability of catalytic current amplification (EC') to reduce this problem, an effect we term "electrocatalytic interruption". Specifically, we show that the increase in mass transport produced by a coupled chemical reaction significantly mitigates edge effects, returning estimated particle size distributions much closer to those observed using ex situ electron microscopy. In parallel, electrocatalytic interruption enhances the signal observed from individual particles, enabling the detection of particles significantly smaller than is possible via conventional blocking electrochemistry. Finite element simulations indicate that the rapid chemical kinetics created by this approach contributes to the amplification of the electronic signal to restore analytical precision and reliably detect and characterize the heterogeneity of nanoscale electro-inactive materials.

Assessing the Impact of Serious Illness on Patient Intimacy and Sexuality in Palliative Care.

CONTEXT: Palliative care (PC) clinical practice guidelines recommend providers assess the impact of illness on intimacy and sexuality. Previous studies around sexuality and intimacy in patients with advanced illness have largely focused on patients with a cancer diagnosis in the outpatient setting. Little is known about such impact of illness on inpatients receiving PC consultation. OBJECTIVES: To assess the impact of patient illness on intimacy and sexuality through use of a screening tool and brief clinical questionnaire in hospitalized patients receiving PC consultation. METHODS: Between January 2016 and May 2017, palliative social workers at three hospitals asked patients to report the level of impact that their illness(es) had on intimacy and to describe the impact. Data were analyzed using descriptive statistics and chi-square analysis. Qualitative data were analyzed using constant comparison methodology. RESULTS: Among the 97 PC patients screened for intimacy concerns, the majority were female (57.7%), African American (71.1%) and on average 57.9 years of age. Most (91.7%) reported that they had not been previously asked about how their illness had impacted their intimacy. Nearly half (48.4%) reported that illness had moderately or significantly impacted their intimacy; these patients tended to be younger and in a current relationship (P < 0.05). CONCLUSION: Patients with advanced illness commonly report negative issues regarding intimacy and sexual health. Incorporating routine screening into PC consultation may be warranted.

Smoking history and Alzheimer's disease risk in a community-based clinic population.

BACKGROUND: The relationship between cigarette smoking and development of Alzheimer's disease (AD) is not fully determined, and previous reports disagree, with some studies suggesting an increased relative risk and others a decreased odds ratio. Consequently, we wanted to determine if the prevalence of past cigarette smoking observed in a community-based clinic sample of patients with AD would be more consistent with the expected value obtained from a model using either an increased relative risk or a decreased odds ratio to estimate the effect of smoking on development of AD. MATERIALS AND METHODS: Retrospective cross-sectional analysis of all patients treated for AD in a community-based Neurology Clinic during a 2-year period. Estimates of expected past smoking prevalence were calculated based on published values for either an increased relative risk or a decreased odds ratio and compared to the past smoking prevalence observed in the clinic sample. RESULTS: The observed past smoking prevalence in the clinic population was 29.17%. The expected past smoking prevalence calculated using the increased relative risk was 30.07% (95% confidence interval [CI] = 27.67-32.32%), and using the decreased odds ratio was 12.54% (95% CI = 6.32-24.81%). CONCLUSION: The observed past smoking prevalence among the patients being treated for AD in a community-based clinic falls within the expected 95% CI for the increased relative risk model and outside of the expected 95% CI for the decreased odds ratio model. These results support the contention that the relationship between cigarette smoking and development of AD is the best characterized by an increased relative risk.

α7-Nicotinic acetylcholine receptor inhibition by indinavir: implications for cognitive dysfunction in treated HIV disease.

OBJECTIVE: The study set out to determine if the HIV protease inhibitor, indinavir, alters responsiveness of α7-nicotinic acetylcholine receptors to acetylcholine. DESIGN: Treatment with HAART has dramatically reduced development of HIV-associated dementia and more severe forms of cognitive impairment. However, many individuals continue to experience cognitive decline of uncertain cause. Previous studies have failed to demonstrate significant alterations of functional brain connectivity, structural brain changes, or changes in cerebral blood flow sufficient to explain cognitive decline in virally suppressed individuals. This suggests that the mechanisms underlying development and progression of cognitive problems likely occurs at a micro rather than macro level, such as disruptions in neurotransmitter system signaling. MATERIALS AND METHODS: Indinavir's effects on α7-nicotinic acetylcholine receptor activity was tested using a ScreenPatch IonWorks Barracuda-based assay in a mammalian cell model. RESULTS: At low concentrations (0.0003-10 µmol/l) indinavir acts as a positive allosteric modulator (EC50 = 0.021 µmol/l), whereas at concentrations greater than 10 µmol/l (30-100 µmol/l) indinavir acts as an inhibitor of the α7-nicotinic acetylcholine receptor. CONCLUSION: At concentrations greater than 10 µmol/l indinavir reduces synaptic transmission in the acetylcholine neurotransmitter system, which could possibly contribute to cognitive dysfunction. These results suggest that further experiments should be considered to assess whether patients might benefit from treatment with cholinesterase inhibitors that counteract the effects of indinavir.

Enabling Anyone to Translate Clinically Relevant Ideas to Therapies.

How do we inspire new ideas that could lead to potential treatments for rare or neglected diseases, and allow for serendipity that could help to catalyze them? How many potentially good ideas are lost because they are never tested? What if those ideas could have lead to new therapeutic approaches and major healthcare advances? If a clinician or anyone for that matter, has a new idea they want to test to develop a molecule or therapeutic that they could translate to the clinic, how would they do it without a laboratory or funding? These are not idle theoretical questions but addressing them could have potentially huge economic implications for nations. If we fail to capture the diversity of ideas and test them we may also lose out on the next blockbuster treatments. Many of those involved in the process of ideation may be discouraged and simply not know where to go. We try to address these questions and describe how there are options to raising funding, how even small scale investments can foster preclinical or clinical translation, and how there are several approaches to outsourcing the experiments, whether to collaborators or commercial enterprises. While these are not new or far from complete solutions, they are first steps that can be taken by virtually anyone while we work on other solutions to build a more concrete structure for the "idea-hypothesis testing-proof of concept-translation-breakthrough pathway".

Lower Frequency of co-Morbid Medical Disorders Related to Poor Impulse Control in Parkinson's than Alzheimer's Disease.

Parkinson's disease is associated with progressive degeneration of mesolimbic dopaminergic neurons that are involved in reward-based behavior learning, including rewarding effects of food consumption and drugs of abuse. The importance of this pathway in development of addictive behaviors led us to hypothesize that medical disorders related to poor impulse control may occur less frequently among patients with Parkinson's disease than those with other progressive neurodegenerative disorders such as Alzheimer's disease. Retrospective cross-sectional study of all patients treated for Parkinson's disease and Alzheimer's disease in a community based clinic during a two-year period. Associations were summarized using odds ratios (OR) and 95% confidence intervals (95% CI) estimated from logistic regression models, adjusted for differences in gender distribution between the groups. A total of 106 patients with Parkinson's disease and 72 patients with Alzheimer's disease were included. Patients with Parkinson's disease were less likely to have either past substance use (adjusted OR = 0.035, 95% CI = 0.009 - 0.130) or presence of co-morbid medical conditions related to poor dietary choices (adjusted OR = 0.157, 95% CI = 0.062 - 0.397). Co-morbid medical conditions related to poor impulse control occur less frequently among those with Parkinson's disease than those with Alzheimer's disease. These findings are consistent with dysfunction of dopamine dependent pathways involved in addiction during the presymptomatic phase of Parkinson's disease and support a biological basis for addiction.

Acute Psychosis Associated with Subcortical Stroke: Comparison between Basal Ganglia and Mid-Brain Lesions.

Acute onset of psychosis in an older or elderly individual without history of previous psychiatric disorders should prompt a thorough workup for neurologic causes of psychiatric symptoms. This report compares and contrasts clinical features of new onset of psychotic symptoms between two patients, one with an acute basal ganglia hemorrhagic stroke and another with an acute mid-brain ischemic stroke. Delusions and hallucinations due to basal ganglia lesions are theorized to develop as a result of frontal lobe dysfunction causing impairment of reality checking pathways in the brain, while visual hallucinations due to mid-brain lesions are theorized to develop due to dysregulation of inhibitory control of the ponto-geniculate-occipital system. Psychotic symptoms occurring due to stroke demonstrate varied clinical characteristics that depend on the location of the stroke within the brain. Treatment with antipsychotic medications may provide symptomatic relief.

The Effects of Declining Functional Abilities in Dementia Patients and Increases Psychological Distress on Caregiver Burden Over a One-Year Period.

The degree to which changes in caregiver burden over a one year period can be predicted by functioning of dementia patients and caregiver psychological stress was examined. The Direct Assessment of Functional Status (DAFS) was administered to 44 patients and the Caregiver Burden Inventory and the Brief Symptom Inventory were administered to their next-of-kin caregivers. All patients and caregivers were assessed at baseline and again in approximately one year with the same measures. Hierarchical regression revealed that baseline patient functioning predicted overall changes in caregiver burden, but that increases in psychological symptoms of caregivers such as depression, anxiety and hostility were the best predictors for specific types of increased caregiver burden, such as social, developmental, or physical burden. These results suggest that interventions should target reduction of particular psychological symptoms in order to reduce caregiver burden over time.

Aspects of Attention Predict Real-World Task Performance in Alzheimer's Disease.

More research is needed to examine the relationship between specific neuropsychological functions and observation-based daily activity tests in patients with Alzheimer's disease (AD). Fifty-six patients with AD were administered tests of attention and processing speed and an observation-based activities-of-daily-living (ADL) task. Complex short-term attention capacity best predicted real-world task performance, accounting for several domains of ADL functioning. These results suggest that complex attention requiring working-memory systems, but not simple attention or processing speed, account for moderate portions of variability in daily task performance. These results may aid in understanding the attentional processes required for performing daily activities and can be useful to health care professionals in treatment planning.

A small-molecule inhibitor of tgf-Beta signaling replaces sox2 in reprogramming by inducing nanog.

The combined activity of three transcription factors can reprogram adult cells into induced pluripotent stem cells (iPSCs). However, the transgenic methods used for delivering reprogramming factors have raised concerns regarding the future utility of the resulting stem cells. These uncertainties could be overcome if each transgenic factor were replaced with a small molecule that either directly activated its expression from the somatic genome or in some way compensated for its activity. To this end, we have used high-content chemical screening to identify small molecules that can replace Sox2 in reprogramming. We show that one of these molecules functions in reprogramming by inhibiting Tgf-beta signaling in a stable and trapped intermediate cell type that forms during the process. We find that this inhibition promotes the completion of reprogramming through induction of the transcription factor Nanog.

Construction of a large synthetic human scFv library with six diversified CDRs and high functional diversity.

Antibody phage display provides a powerful and efficient tool for the discovery and development of monoclonal antibodies for therapeutic and other applications. Antibody clones from synthetic libraries with optimized design features have several distinct advantages that include high stability, high levels of expression, and ease of downstream optimization and engineering. In this study, a fully synthetic human scFv library with six diversified CDRs was constructed by polymerase chain reaction assembly of overlapping oligonucleotides. In order to maximize the functional diversity of the library, a beta-lactamase selection strategy was employed in which the assembled scFv gene repertoire was fused to the 5'-end of the beta-lactamase gene, and in-frame scFv clones were enriched by carbenicillin selection. A final library with an estimated total diversity of 7.6 x 10(9), greater than 70% functional diversity, and diversification of all six CDRs was obtained after insertion of fully randomized CDR-H3 sequences into this proofread repertoire. The performance of the library was validated using a number of target antigens, against which multiple unique scFv sequences with dissociation constants in the nanomolar range were isolated.

Relative hyperperfusion by SPECT in a family with a presenilin 1 (T245P) mutation.

Clinical characteristics of autosomal dominant Alzheimer's disease often differ clinically from sporadic disease with the onset of seizures, spasticity and myoclonus early in the disease course. Similarly imaging characteristics may also differ. We report the findings of relative hyperperfusion by Tc-99m HMPAO SPECT in the medial orbitofrontal cortex and anterior temporal lobe in four affected family members carrying a presenilin 1 mutation. SPECT of the four individuals was compared to an age-matched normal database. We speculate that the findings of relative medial orbitofrontal and anterior temporal lobe hyperperfusion may be a marker of early onset Alzheimer's disease in this family.

A presenilin-1 mutation (T245P) in transmembrane domain 6 causes early onset Alzheimer's disease.

We report a presenilin-1 mutation (T245P) in a Japanese-American family with autosomal dominant Alzheimer's disease with an onset age in the early 40s. The early clinical features were remarkable for their purely amnestic nature. The position of the mutation is in the transmembrane domain that harbors the aspartic acid residue which is believed to be part of the active site of gamma-secretase.

Population pharmacokinetics of daptomycin.

Data from subjects in nine phase 1 (n = 153) and six phase 2/3 (n = 129) clinical trials were combined to identify factors contributing to interindividual variability in daptomycin pharmacokinetics (PK). Over 30 covariates were considered. A two-compartment model with first-order elimination provided the best fit for data on daptomycin concentrations in plasma over time. In the final population PK model, daptomycin plasma clearance (CL) was a function of renal function, body temperature, and sex. Of these factors, renal function contributed most significantly to interindividual variability. CL varied linearly with the estimated creatinine clearance. CL among dialysis subjects was approximately one-third that of healthy subjects (0.27 versus 0.81 liter/h). CL in females was 80% that in males; however, in clinical trials, the outcome was not affected by sex and therefore this effect is not considered clinically meaningful. The relationship with body temperature should be interpreted cautiously since the analysis included only a limited number of subjects who were hyperthermic. The volume of distribution of the peripheral compartment (V2) and intercompartmental clearance (Q) were linearly related to body weight. V2 increased approximately twofold in the presence of an acute infection. No factors were identified that significantly impacted V1. This analysis supports the dosing of daptomycin on a milligram-per-kilogram-of-body-weight basis and suggests that modified dosing regimens are indicated for patients with severe renal disease and for those undergoing dialysis.