VA Northern California Health Care System

Dopamine drives the neuronal activity and synaptic plasticity required for various forms of learning. It supports short-term working memory through activation of the D1-like dopamine receptors D1 and D5. Here, we found that the L-type Ca2+ channel CaV1.2 was a critical mediator of D1/5 signaling in hippocampal pyramidal neurons. In cultured mouse hippocampal neurons, a D1/5 agonist augmented currents through CaV1.2 in the soma and Ca2+ influx in the dendrites. This effect was mediated through the second messenger cAMP and cAMP-dependent protein kinase (PKA), which phosphorylated the CaV1.2 α1 subunit at Ser1928. CaV1.2 and D5 colocalized, suggesting that this signaling was spatially restricted. In mice, D1/5 agonism facilitated spatial working memory in wild-type but not litter-matched CaV1.2 α1 S1928A knockin animals. These findings identify CaV1.2 as a key D1/5 signaling effector that supports dopamine-driven executive functions in cognition.

ABSTRACT Introduction Pneumonia is a major cause of death and disability worldwide. A host of pathogens causes pneumonia, and pneumonia presents with a remarkable heterogeneity of clinical symptoms and signs and has varied outcomes. Current approaches to pneumonia diagnosis and risk stratification lack precision such that there is no universally agreed upon biomarker or scoring system. These limitations have prompted calls for novel, noninvasive, and more precise approaches to better diagnosing pneumonia and predicting outcomes. Areas covered We performed a comprehensive literature search through PubMed to identify studies reporting on breath biomarkers in pneumonia published up to 31 July 2025. This manuscript explores breath-based metabolomics as a novel approach to biomarker development in pneumonia. It describes breath collection methods, including devices available and types of breath samples for analysis. It reviews the potential role of exhaled breath analysis to expedite pneumonia diagnosis, monitor response to therapy, and predict clinical trajectory. Expert opinion Breath-based metabolomics could improve the recognition and management of pneumonia. It is a noninvasive, potentially continuous method that provides a direct window into the lung for novel insights into the underlying biology of pneumonia.

Gait impairments are a well-documented consequence of stroke, yet the impact of transient ischemic attack (TIA) on gait remains underexplored. This study aimed to characterize acute changes in gait patterns within three days of stroke or TIA onset using an accelerometer, and to examine the relationship between gait patterns and questionnaire-based measures of balance confidence. We found that patients with TIA showed significantly lower variability in swing time, stance time, and step time than patients with stroke. Comparisons between patients with TIA and controls indicated that controls had higher mean step velocity and lower step time asymmetry. Additionally, compared with controls, patients with stroke demonstrated a slower and less temporally consistent pace, indicated by shorter step length, lower step velocity, and higher standard deviation (SD) for swing time, stance time, and step time. They also showed greater variability, reflected by higher step length SD, and more pronounced gait asymmetry, with greater asymmetry in swing time, step time, and stance time. The balance confidence was associated with gait parameters in patients with stroke and in controls, but not in patients with TIA. In both groups, higher confidence related to longer step length and faster step velocity; in stroke it was also linked to lower swing time variability and longer step and stance times, and in controls to lower step time variability. These findings demonstrate that TIA involves detectable neurological changes affecting motor control, highlighting the value of detailed accelerometer-based gait analysis for early detection of functional deficits.

Identifying microbial contamination early in cell culture processing can save time, money, and reagents. However, standard strategies for performing contamination testing often take days, leaving production vulnerable to potential spread of bacteria, mold, and mycoplasma. Volatile organic compounds (VOCs) are released by every living organism. These VOCs are increasingly being used to identify cell pathologies, study cell metabolomics, and assess other biological processes. Often, gas chromatography with mass spectrometry (GC-MS) is used to perform these analyses. Here, we utilized gas chromatography with ion mobility spectrometry (GC-IMS) to detect bacteria, mold, and mycoplasma in both cell and tissue cultures. Traditional GC-MS was used to validate the detection of microbes in cell cultures using GC-IMS. In most cases, headspace samples were collected just two hours after inoculations. GC-IMS was able to detect as low as 10 CFU of 5 different industry standard microbes, including both bacteria and mold species. In addition, mycoplasma presence, which is notoriously difficult to test, was detectable at 24 h post-inoculation. GC-IMS is highly sensitive, has a small footprint, requires minimal training, and can provide results in as little as 20 min per sample. Combined, this makes it an ideal strategy for detecting contamination in cell and tissue production workflows. Such rapid detection could save substantial amounts of time, money, and valuable reagents, and reduce risks to patient safety.

IntroductionChronic wounds are a significant source of patient morbidity, and ineffective treatment can lead to complications that are difficult and costly to manage. Given the limitations of current therapies, repurposing medications with well-studied safety and accessibility profiles offers a promising strategy for advancing wound care.MethodsA comprehensive review of the existing literature was conducted to evaluate the role of serotonin-modulating pharmacotherapy in wound healing.ResultsSerotonergic signaling plays a multifaceted role in wound healing and evidence increasingly supports serotonin-modulating pharmacotherapy as having favorable angio-regulatory, immunomodulatory, and antimicrobial wound healing effects. Preclinical and clinical studies have demonstrated that topical administration of serotonin-modulating pharmacotherapy may improve wound healing outcomes.Discussionfindings of this study provide support for the use of serotonin-modulating pharmacotherapy, with a special focus on topical application, as an adjunctive treatment for chronic, non-healing wounds and highlight the need for further translational clinical investigation.

BACKGROUND:Diabetic hyperglycemia promotes vasoconstriction by activating an ATP-dependent P2Y11L (P2Y11-like receptor)/AC5 (adenylyl cyclase 5)/AKAP5 (A-kinase anchoring protein 5)/PKA (protein kinase A)/CaV1.2 (L-type voltage-dependent calcium channel 1.2) nanocomplex in arterial myocytes, but upstream mechanisms are unclear. We hypothesized that Panx1 (pannexin 1) channels, which facilitate ATP release, are associated with the complex in arterial myocytes and mediate its activation to induce vasoconstriction during diabetic hyperglycemia.METHODS:Multidisciplinary approach using extracellular ATP and cAMP biosensors, patch-clamp electrophysiology, super-resolution nanoscopy, proximity ligation assay, pressure myography, and laser speckle imaging to test premises in arterial myocytes and vessels from wild-type and genetically modified mice, including an inducible smooth muscle–specific Panx1 knockout and a global AKAP5 knockout.RESULTS:We found that elevating extracellular glucose (eg, high glucose, hyperglycemia) triggered an increase in extracellular ATP levels, and this was reduced in the presence of the Panx1 inhibitor spironolactone, in inducible smooth muscle–specific Panx1 knockout cells, and by inhibiting glucose metabolism. Panx1 was found in complex with P2Y11L, AC5, AKAP5, PKA, and CaV1.2 in arterial myocytes. The protein complex was strengthened in response to hyperglycemia, which required Panx1 and AKAP5. Hyperglycemia–induced cAMP production, CaV1.2 potentiation, sustained vasoconstriction, and in vivo changes in cerebral artery myogenic tone and blood flow were ameliorated by spironolactone and in inducible smooth muscle–specific Panx1 knockout samples. Panx1 expression was elevated in arterial lysates from a mouse model of type 1 diabetes (eg, streptozotocin), and increased CaV1.2 activity and enhanced ex vivo and in vivo myogenic tone were prevented in arterial myocytes and arteries from inducible smooth muscle–specific Panx1 knockout mice.CONCLUSIONS:These results suggest a key role for Panx1 in controlling ATP signaling through the P2Y11L/AC5/AKAP5/PKA/CaV1.2 axis in arterial myocytes. This Panx1-led complex modulates cAMP levels, CaV1.2 activity, and vascular reactivity in response to diabetic hyperglycemia. Thus, Panx1 could be a new therapeutic target to mitigate vascular complications during diabetes.

Dysregulation of brain state is common following traumatic brain injury (TBI), contributing to long-term difficulties in important life pursuits, spanning school, work, and beyond. Brain state dysregulation makes it difficult to effectively organize and direct cognition and behavior to accomplish any number of goals, resulting instead in difficult-to-understand combinations of neurocognitive and emotional symptoms: distractibility, forgetfulness, poor follow-through, irritability, reduced frustration tolerance, and becoming easily overwhelmed. Given underlying heterogeneity with neurocognitive-emotional symptoms, it may be highly efficient to train use of state regulation skills (SRS) as a generalizable approach to facilitate processing of neurocognitive demands encountered along individual goal pathways. In this report, we present an innovative system of guided experiential skill learning of goal-directed SRS - one that rationally integrates experiential digital technology designed to practice applying and integrating SRS directly into goal-based functional challenges with therapist-led training to maximize skill learning, transfer, and generalization. Moreover, we designed this system specifically to bridge important gaps that interfere with skill learning when individuals are remote from therapists. To advance the integration of technology into rehabilitation neuroscience, we present this communication as a hybrid of intervention design (introducing principles and features), "user experiences" (sharing vignettes informative of the value of technology integration into the learning process), and a controlled, proof-of-principle pilot intervention study for a small cohort of individuals (n = 18) with chronic TBI (assessing the plausibility of strengthening goal-directed functioning, as indexed by performance on neurocognitive assessment tasks and complex functional tasks, as well as ratings of personal life functioning). Data suggest that a technology-augmented remote guided experiential learning approach may bridge important gaps in skill learning to help individuals improve goal-directed functioning. This line of work will inform further advances in remote neuro-cognitive rehabilitation.

To determine whether cellular matrix (CM) products result in better healing rates than acellular matrix (ACM) products for nonhealing diabetic foot ulcers. The Dermagraft and Oasis Longitudinal Comparative Efficacy Study (DOLCE) was a randomized, single-blinded, three-arm controlled trial. Patients (aged ≥18 years) with a full-thickness nonhealing diabetic foot ulcer who met inclusion/exclusion criteria were enrolled. Of 169 eligible patients, 138 were enrolled and 117 randomly assigned. For 12 weeks, patients received standard of care (SOC), CM, or ACM. The primary outcome was the percentage of wounds healed by 12 weeks. Of the 117 participants, 41 were in the CM group, 48 in the ACM group, and 28 in the SOC group. There were 21 withdrawals, but seven had reached the first primary end point. Complete re-epithelialization of the ulcer by 12 weeks occurred in 59% of the 117 total participants: 49% in the CM group, 69% in the ACM group, and 57% in the SOC group (P = 0.16 by χ2 test). At 28 weeks, 25 participants (61%) in the CM group, 27 (56%) in the ACM group, and 18 (64%) in the SOC group had healed (P = 0.78). No differences were found in wound recidivism or adverse event occurrence between groups. No difference in efficacy was found between SOC, ACM, and CM, suggesting that SOC can reduce the economic burden of diabetic foot ulcer treatment.

Introduction: Diabetic foot ulcers (DFUs) are a common complication in diabetes, leading to high amputation risk and significant healthcare costs. Given topical timolol’s emergence as a potential wound-healing agent, our study explored its impact on epidermal integrity. Methods: This study was a post hoc analysis conducted as part of a randomized controlled trial at the Veterans Affairs Northern California Health Care System. Twenty patients, who had DFUs healed in the original trial, 10 in the timolol arm, and 10 in the placebo arm, were enrolled in the study. The primary outcome was transepidermal water loss, measured monthly for 3 months of post-healing using a closed-chamber device. The secondary outcome was re-ulceration rates over 1 year. Results: Transepidermal water loss at 1, 2, and 3 months of post-healing was significantly lower in the timolol group than in the placebo group (p < 0.01). Linear mixed models identified contralateral foot transepidermal water loss as a significant predictor of healed diabetic foot ulcer site transepidermal water loss (estimate = 0.76, p < 0.001). The interaction between timolol treatment and months since healing significantly reduced transepidermal water loss over time (estimate = −2.2, p = 0.002). The use of a wheelchair was also associated with a significant decrease in transepidermal water loss (estimate = −7.7, p = 0.01). Initial transepidermal water loss values were higher in patients who re-ulcerated, but the difference was not statistically significant (p = 0.42). There was no difference in re-ulceration rates in this small pilot study. Conclusion: Topical timolol significantly improved skin barrier function in healed DFUs, reducing transepidermal water loss. Although re-ulceration rates were not significantly different, the trend suggests potential benefits. Further studies with larger sample sizes and longer follow-up are needed to confirm these findings and explore transepidermal water loss’s predictive value for re-ulceration.