Planar amorphous silicon carbide microelectrode arrays for chronic recording in rat motor cortex.

Chronic implantation of intracortical microelectrode arrays (MEAs) capable of recording from individual neurons can be used for the development of brain-machine interfaces. However, these devices show reduced recording capabilities under chronic conditions due, at least in part, to the brain's foreign body response (FBR). This creates a need for MEAs that can minimize the FBR to possibly enable long-term recording.

Reactive Amine Functionalized Microelectrode Arrays Provide Short-Term Benefit but Long-Term Detriment to Recording Performance.

Intracortical microelectrode arrays (MEAs) are used for recording neural signals. However, indwelling devices result in chronic neuroinflammation, which leads to decreased recording performance through degradation of the device and surrounding tissue. Coating the MEAs with bioactive molecules is being explored to mitigate neuroinflammation.

The effect of a Mn(III)tetrakis(4-benzoic acid)porphyrin (MnTBAP) coating on the chronic recording performance of planar silicon intracortical microelectrode arrays.

Intracortical microelectrode arrays (MEAs) are used to record neural activity. However, their implantation initiates a neuroinflammatory cascade, involving the accumulation of reactive oxygen species, leading to interface failure. Here, we coated commercially-available MEAs with Mn(III)tetrakis(4-benzoic acid)porphyrin (MnTBAP), to mitigate oxidative stress.

Antioxidant Dimethyl Fumarate Temporarily but Not Chronically Improves Intracortical Microelectrode Performance.

Intracortical microelectrode arrays (MEAs) can be used in a range of applications, from basic neuroscience research to providing an intimate interface with the brain as part of a brain-computer interface (BCI) system aimed at restoring function for people living with neurological disorders or injuries. Unfortunately, MEAs tend to fail prematurely, leading to a loss in functionality for many applications. An important contributing factor in MEA failure is oxidative stress resulting from chronically inflammatory-activated microglia and macrophages releasing reactive oxygen species (ROS) around the implant site.

Chronic Stability of Local Field Potentials Using Amorphous Silicon Carbide Microelectrode Arrays Implanted in the Rat Motor Cortex.

Implantable microelectrode arrays (MEAs) enable the recording of electrical activity of cortical neurons, allowing the development of brain-machine interfaces. However, MEAs show reduced recording capabilities under chronic conditions, prompting the development of novel MEAs that can improve long-term performance. Conventional planar, silicon-based devices and ultra-thin amorphous silicon carbide (a-SiC) MEAs were implanted in the motor cortex of female Sprague-Dawley rats, and weekly anesthetized recordings were made for 16 weeks after implantation.

Characterization of Active Electrode Yield for Intracortical Arrays: Awake versus Anesthesia.

Intracortical microelectrode arrays are used for recording neural signals at single-unit resolution and are promising tools for studying brain function and developing neuroprosthetics. Research is being done to increase the chronic performance and reliability of these probes, which tend to decrease or fail within several months of implantation. Although recording paradigms vary, studies focused on assessing the reliability and performance of these devices often perform recordings under anesthesia.

Intracortical Microelectrode Array Unit Yield under Chronic Conditions: A Comparative Evaluation.

While microelectrode arrays (MEAs) offer the promise of elucidating functional neural circuitry and serve as the basis for a cortical neuroprosthesis, the challenge of designing and demonstrating chronically reliable technology remains. Numerous studies report "chronic" data but the actual time spans and performance measures corresponding to the experimental work vary. In this study, we reviewed the experimental durations that constitute chronic studies across a range of MEA types and animal species to gain an understanding of the widespread variability in reported study duration.

Effects of 100 % oxygen during exercise in patients with interstitial lung disease.

Purpose: Hypoxemia limits exercise in some patients with interstitial lung disease (ILD). High levels of supplemental oxygen during exercise might allow physical training at a higher level and more effective pulmonary rehabilitation (PR). Our goals were to use graded cardiopulmonary exercise testing (CPET) to determine whether hyperoxia (FO≈1.

Braden score may be associated with time to onset of catheter-associated urinary tract infection in high-risk patients: Lessons learned from a root cause analysis tool.

Timely removal of the urinary catheter is an important strategy for decreasing catheter-associated urinary tract infections (CAUTIs). Data were aggregated from an electronic root cause analysis tool, which is used to collect and guide discussions on patient factors following a CAUTI event at our facility. This identified the Braden Scale score as a possible important predictor of early-onset CAUTI in high-risk patients and could potentially be leveraged for early action in urinary catheter removal.

Unexplained acute renal failure in a toddler: a rare complication of Epstein-Barr virus.

A previously healthy toddler developed severe acute renal failure with nephromegaly and peripheral atypical lymphocytosis. Profound interstitial nephritis with acute tubular necrosis was diagnosed by renal biopsy, and both the clinical picture and serological evaluation suggested Epstein-Barr virus (EBV) as the etiological agent. The previous reports of EBV-induced renal failure and the clinical and pathological presentations of interstitial nephritis in children are reviewed.

Transforming growth factor-beta levels in human allograft chronic fibrosis correlate with rate of decline in renal function.

Background: Long-term renal transplant function is limited primarily by a progressive scarring process loosely termed "chronic rejection, chronic allograft nephropathy, or allograft fibrosis." Although the etiology of transplant fibrosis is uncertain, several possible factors including chronic cyclosporin A (CsA) exposure may contribute to its pathogenesis. CsA stimulates renal fibrosis perhaps through the induction of the potent pro-sclerotic growth factor, transforming growth factor beta (TGFbeta).

Increased renal tubular expression of transforming growth factor beta in human allografts correlates with cyclosporine toxicity.

Cyclosporine A (CsA) is a potent immunosuppressive drug that inhibits the transcription of several proinflammatory cytokines including interleukin-2. In contrast, CsA stimulates transcription of the pleuripotent cytokine, transforming growth factor-beta (TGF beta). Since the effect of CsA in transplant recipients is unpredictable, we examined whether tissue levels of TGF beta protein in renal allografts correlate with in vivo CsA responsiveness.

Influence of the interview on the evaluation of applicants to medical school.

Purpose: To determine whether medical school admission interviewers change their evaluations and impressions of applicants as a direct result of the interview.

Method: In 1991-92, 419 applicants to the University of Virginia School of Medicine were interviewed by members of the admission committee in two separate half-hour sessions. After reviewing each applicant's folder, interviewers rated the applicant before the interview on six objective scales.

Membranoproliferative glomerulonephritis with primary Sjögren's syndrome.

Glomerular involvement in primary Sjögren's syndrome is rare and only five cases of membranoproliferative glomerulonephritis have been reported. We present a case of a 31-year-old white woman with primary Sjögren's syndrome who developed nephrotic syndrome. Evaluation showed no evidence of an associated connective tissue disease.

Study of EHS type IV collagen lacking Goodpasture's epitope in glomerulonephritis in rats.

The Goodpasture's epitope has been mapped to the alpha 3 non-collagenous chain (NC1) of type (IV) collagen [alpha 3col(IV)]. We have developed a model of experimental autoimmune glomerulonephritis (EAG) in rats immunized once with collagenase solubilized GBM (csGBM). Engelbreth-Holm-Swarm (EHS) tumor contains abundant col(IV) with little or no alpha 3col(IV).

Juxtaglomerular body abnormalities in youth-onset diabetic subjects.

Abnormal microalbuminuria in insulin-dependent diabetic subjects (IDDS) is significantly associated with pre-clinical nephropathy. In youth-onset IDDS declining plasma renin activity is significantly associated with improved albumin excretion, while persistently elevated renin activity is associated with continued abnormal microalbuminuria. To determine if these changes are reflected in changes in cell count in the juxtaglomerular body and if biopsy findings correlate with abnormal microalbuminuria, renal tissue of 20 IDDS (Study IDDS) ages 16 to 31 years, evaluated concurrently for plasma renin activity and microalbuminuria, were examined by light microscopy.

Proliferative autoimmune glomerulonephritis in rats: a model for autoimmune glomerulonephritis in humans.

Some forms of glomerulonephritis (GN) in humans appear consequent to autoimmunity. Experimental autoimmune GN (EAG) has been described in sheep, but attempts to develop EAG in other mammals have resulted only in antibody and proteinuria but no GN. We have developed a model of EAG in an inbred mammalian species to further study pathogenetic mechanisms.

Long-term oral or intravenous aluminum administration in rabbits. I. Renal and hepatic changes.

Long-term aluminum (Al) administration was studied in rabbits using intravenous (I.V.) injections of aluminum maltol or oral aluminum citrate in drinking water along with calcium.

Distribution of renin mRNA and its protein in the developing kidney.

The intrarenal distribution of renin changes markedly during maturation. To determine whether renin gene expression changes along the developing renal vasculature, renin mRNA distribution was assessed using in situ hybridization histochemistry. Fetal, newborn, and adult kidney tissue sections from Wistar-Kyoto rats were hybridized with an oligonucleotide complementary to rat renin mRNA.

Disparate urinary catecholamine patterns in secondary hypertension due to unique sequential development of pheochromocytoma and neuroblastoma.

A 43-year-old white woman had a pheochromocytoma removed from her left adrenal gland, and one year later she developed a new left upper abdominal mass that was found to be a neuroblastoma. On both occasions, urinary vanillylmandelic acid level was elevated. However, urinary norepinephrine and epinephrine levels were increased only during the pheochromocytoma episode, while the urinary homovanillic acid level was elevated only when neuroblastoma developed.

A long-term intravenous model of aluminum maltol toxicity in rabbits: tissue distribution, hepatic, renal, and neuronal cytoskeletal changes associated with systemic exposure.

We studied the toxicity of an intravenously injected, water-soluble aluminum complex (aluminum maltol) in 20 young adult male New Zealand white rabbits over a period of 8 to 30 weeks. Sixteen rabbits injected with aluminum-free maltol and 15 untreated rabbits served as controls. Rabbits were injected three times per week with 75 mumol of aluminum maltol per injection, or a molar equivalent amount of maltol alone, through an indwelling jugular catheter.

Methylprednisolone therapy for acute crescentic rapidly progressive glomerulonephritis.

In the last 10 years we have evaluated 63 patients with acute crescentic rapidly progressive glomerulonephritis (AC-RPGN), 46 of whom received pulse methylprednisolone (PM). The groups consisted of patients with no immune deposits, immune complexes, vasculitis, and antiglomerular basement membrane (anti-GBM) disease. Seventy-nine percent of non-anti-GBM patients improved versus 25% of unpulsed, p less than 0.

Transfer of experimental glomerulonephritis in chickens by mononuclear cells.

We have produced experimental autoimmune glomerulonephritis (EAG) in histocompatible SC chickens by immunization with different types of glomerular antigen. The development of EAG was time, but not antigen, dependent. Transfer of mononuclear cells from spleens and kidneys of nephritic animals resulted in EAG in naive recipients.