COVID-19 Pandemic Associated With Increased Self-reported Depressive Symptoms in Patients With Congenital Craniofacial Diagnoses.

OBJECTIVE: The current study investigated the influence of the coronavirus (COVID-19) pandemic on patients with congenital craniofacial diagnoses. METHODS: Patients (n = 66) with craniofacial diagnoses aged between 8 and 17 were prospectively evaluated with longitudinal psychosocial assessments using the anger, anxiety, depressive symptoms, and peer relationships instruments within the pediatric Patient-Reported Outcomes Measurement Information System (PROMIS). The COVID-19 cohort (n = 33) included patients with assessments within 2 years prior to the pandemic (t0) and during the pandemic (t1; March 2020 to March 2021). An age-matched comparison cohort (n = 33) with similar demographics and diagnoses included patients assessed twice over 3 years prior to the pandemic. RESULTS: All PROMIS measures were in the average range clinically for both groups across time points. However, the COVID-19 group reported a significant increase in depressive symptoms during the pandemic (t1) compared to pre-pandemic (t0) scores (48.2 ± 10.1 vs 44.3 ± 9.4, P = .04, d = -0.37), while the comparison group did not demonstrate any differences in psychosocial functioning between t0 and t1. For the COVID-19 cohort, only the pandemic timeframe (r = 0.21, P = .03) was significantly associated with increased depressive symptom scores, and no other sociodemographic or medical variables were associated with depressive symptoms. CONCLUSIONS: Self-reported depressive symptoms increased during the COVID-19 pandemic in patients with congenital craniofacial diagnoses. Longitudinal studies are needed to elucidate whether such changes will be persistent or compound known variables associated with psychosocial functioning.

The history, mechanism, and perspectives of nirmatrelvir (PF-07321332): an orally bioavailable main protease inhibitor used in combination with ritonavir to reduce COVID-19-related hospitalizations.

The rapid development of effective vaccines to combat the SARS-CoV-2 virus has been an effective counter measure to decrease hospitalization and the mortality rate in many countries. However, with the risk of mutated strains decreasing the efficacy of the vaccine, there has been an increasing demand for antivirals to treat COVID-19. While antivirals, such as remdesivir, have had some success treating COVID-19 patients in hospital settings, there is a need for orally bioavailable, cost-effective antivirals that can be administered in outpatient settings to minimize COVID-19-related hospitalizations and death. Nirmatrelvir (PF-07321332) is an orally bioavailable Mpro (also called 3CLpro) inhibitor developed by Pfizer. It is administered in combination with ritonavir, a potent CYP3A4 inhibitor that decreases the metabolism of nirmatrelvir. This review seeks to outline the history of the rational design, the target selectivity, synthesis, drug resistance, and future perspectives of nirmatrelvir. Graphical abstract.

The Analgesic Effects of the Thoracic Paravertebral Block on Post-percutaneous Nephrolithotripsy: A Retrospective Study.

INTRODUCTION: Percutaneous nephrolithotripsy (PCNL) is a minimally invasive procedure for treating large and complex kidney stones, often resulting in significant post-operative pain and increased opioid use. This study aims to compare pain scores between patients undergoing PCNL who did and did not receive a preoperative single-shot thoracic paravertebral block (PVB) at the post-anesthesia care unit (PACU) as the primary outcome. Secondary outcomes were patient-controlled analgesia (PCA) usage on post-operative day 1 (POD 1), total opioid consumption on PACU and POD 1, and post-operative nausea and vomiting (PONV). METHODS: A retrospective cohort study was conducted on the medical records of 341 patients who underwent PCNL from July 2014 to April 2016 in a single major academic center. PVB was administered at thoracic levels T7-9 using a volume of 20 cc of bupivacaine, ranging from 0.25% to 0.5%, to achieve the desired analgesic effect. RESULTS: After excluding 34 patients, the study included 123 in the no block (NB) group and 149 in the regional anesthesia (RA) group. There were no differences in demographics, including age, sex, weight and height, BMI, and indication for PCNL. The results revealed that the RA group experienced a statistically significant reduction in PCA usage in both crude and adjusted models (adjusted logistic regression analysis: OR = 0.19, 95% CI = 0.05-0.60; p = 0.008). However, there were no significant changes in total opioid consumption, pain scores, or incidents of PONV. CONCLUSION: The retrospective analysis did not reveal any discernible advantage in pain management associated with the use of PVB for post-PCNL analgesia, except for reducing the percentage of PCA narcotics used. Future investigations with larger sample sizes and meticulous control for surgical indications and complexity are imperative to accurately assess the efficacy of this block in the context of post-PCNL surgery.

Basal forebrain-lateral habenula inputs and control of impulsive behavior.

Deficits in impulse control are observed in several neurocognitive disorders, including attention deficit hyperactivity (ADHD), substance use disorders (SUDs), and those following traumatic brain injury (TBI). Understanding brain circuits and mechanisms contributing to impulsive behavior may aid in identifying therapeutic interventions. We previously reported that intact lateral habenula (LHb) function is necessary to limit impulsivity defined by impaired response inhibition in rats. Here, we examine the involvement of a synaptic input to the LHb on response inhibition using cellular, circuit, and behavioral approaches. Retrograde fluorogold tracing identified basal forebrain (BF) inputs to LHb, primarily arising from ventral pallidum and nucleus accumbens shell (VP/NAcs). Glutamic acid decarboxylase and cannabinoid CB1 receptor (CB1R) mRNAs colocalized with fluorogold, suggesting a cannabinoid modulated GABAergic pathway. Optogenetic activation of these axons strongly inhibited LHb neuron action potentials and GABA release was tonically suppressed by an endogenous cannabinoid in vitro. Behavioral experiments showed that response inhibition during signaled reward omission was impaired when VP/NAcs inputs to LHb were optogenetically stimulated, whereas inhibition of this pathway did not alter LHb control of impulsivity. Systemic injection with the psychotropic phytocannabinoid, Δ9-tetrahydrocannabinol (Δ9-THC), also increased impulsivity in male, and not female rats, and this was blocked by LHb CB1R antagonism. However, as optogenetic VP/NAcs pathway inhibition did not alter impulse control, we conclude that the pro-impulsive effects of Δ9-THC likely do not occur via inhibition of this afferent. These results identify an inhibitory LHb afferent that is controlled by CB1Rs that can regulate impulsive behavior.

Hydrophobic mismatch drives self-organization of designer proteins into synthetic membranes.

The organization of membrane proteins between and within membrane-bound compartments is critical to cellular function. Yet we lack approaches to regulate this organization in a range of membrane-based materials, such as engineered cells, exosomes, and liposomes. Uncovering and leveraging biophysical drivers of membrane protein organization to design membrane systems could greatly enhance the functionality of these materials. Towards this goal, we use de novo protein design, molecular dynamic simulations, and cell-free systems to explore how membrane-protein hydrophobic mismatch could be used to tune protein cotranslational integration and organization in synthetic lipid membranes. We find that membranes must deform to accommodate membrane-protein hydrophobic mismatch, which reduces the expression and co-translational insertion of membrane proteins into synthetic membranes. We use this principle to sort proteins both between and within membranes, thereby achieving one-pot assembly of vesicles with distinct functions and controlled split-protein assembly, respectively. Our results shed light on protein organization in biological membranes and provide a framework to design self-organizing membrane-based materials with applications such as artificial cells, biosensors, and therapeutic nanoparticles.

Cell-free protein synthesis systems for vaccine design and production.

Vaccines are vital for protection against existing and emergent diseases. Current vaccine production strategies are limited by long production times, risky viral material, weak immunogenicity, and poor stability, ultimately restricting the safe or rapid production of vaccines for widespread utilization. Cell-free protein synthesis (CFPS) systems, which use extracted transcriptional and translational machinery from cells, are promising tools for vaccine production because they can rapidly produce proteins without the constraints of living cells, have a highly optimizable open system, and can be used for on-demand biomanufacturing. Here, we review how CFPS systems have been explored for the production of subunit, conjugate, virus-like particle (VLP), and membrane-augmented vaccines and as a tool in vaccine design. We also discuss efforts to address potential limitations with CFPS such as the presence of endotoxins, poor protein folding, reaction stability, and glycosylation to enable promising future vaccine design and production.

Masculinizing hormone therapy effect on breast tissue: Changes in estrogen and androgen receptors in transgender female-to-male mastectomies.

PURPOSE: Almost two percent of individuals in the United States identify as gender non-conforming. In the female-to-male (FTM) transgender population, masculinizing hormone therapy with testosterone is commonly prescribed in gender transition. To date, the effects of exogenous androgens on breast tissue and its roles in altering breast cancer risk are poorly understood. This study examines the histopathologic findings in gender affirming mastectomy (GAM) in transgender FTM patients and the effects of exogenous androgens on estrogen receptors (ER) and androgen receptors (AR). METHODS: A retrospective review of pathology specimens obtained between 2017 and 2020 was performed comparing androgen exposed breast tissue with breast tissue without androgen exposure. Breast specimens were obtained from patients who underwent FTM GAM with recorded exogenous androgen exposure. Control breast specimens were obtained from reduction mammoplasty (RM) procedures in cisgender women which were aged matched to the GAM cohort, as well as postmenopausal women with benign/prophylactic mastectomy procedures; all controls were without androgen exposure. The histopathologic findings were assessed. Immunohistochemistry for AR and ER was performed and the score interpreted by digital image analysis. RESULTS: Androgen-exposed breast tissue revealed dense fibrotic stroma, lobular atrophy, thickened lobular basement membranes, and gynecomastoid changes. Longer duration of androgen exposure resulted in a more pronounced effect. The incidence of atypia or cancer was lower in GAM than RM cohort. ER and AR expression was highest in transgender male breast tissue with intermediate duration of exogenous androgen exposure. CONCLUSION: Increased androgen exposure is associated with lobular atrophy and gynecomastoid changes in breast parenchyma. Overall, ER and AR are expressed strongly in lobular epithelium in patients with prolonged androgen exposure. Exogenous testosterone does not appear to increase risk for breast cancer. Additional studies are needed to investigate the mechanism responsible for these changes at a cellular level and its role in cancer development.

Meta-Analysis and Meta-Regression of Complications and Failures of Autologous Heterotopic Cranial Bone versus Alloplastic Cranioplasties.

BACKGROUND: Fresh autologous cranial bone graft has been traditionally regarded as the ideal cranioplasty material, however long-term comparisons of outcomes with modern alloplastic materials are absent in the literature. In this work, we evaluated complications and failures among cranioplasties performed with fresh, heterotopic, cranial bone graft versus three common alloplastic materials. METHODS: Random-effects meta-analyses of logit-transformed proportions were performed on studies published between 1971-2021 to evaluate complications and failures of cranioplasties performed with fresh, autologous, heterotopic cranial bone, polyetheretherketone (PEEK), polymethylmethacrylate (PMMA), or titanium with a mean follow-up ≥12 months. Generalized mixed model meta-regressions were performed to account for heterogeneity and to evaluate the contributions of moderators to outcomes variables. RESULTS: 1490 patients (mean age 33.9±10.8 years) were included. Pooled, all-cause complications were 6.2% for fresh, heterotopic, autologous cranial bone (95% confidence interval [CI]:2.1-17.0%; I2=55.0%, p=0.02), 18.5% for PEEK (95%CI:14.0-24.0%; I2=0.0%, p=0.58), 26.1% for titanium (95%CI:18.7-35.1%; I2=60.6%, p<0.01), and 28.4% for PMMA (95%CI:12.9-51.5%; I2=88.5%, p<0.01). Pooled all-cause failures were 2.2% for fresh, autologous cranial bone (95%CI:0.4-10.6%; I2=0.0%, p=0.45), 6.3% for PEEK (95%CI:3.2-12.3%; I2=15.5%, p=0.31), 11.4% for titanium (95%CI:6.7-18.8%; I2=60.8%, p<0.01), and 12.7% for PMMA (95%CI:6.9-22.0%; I2=64.8%, p<0.01). Meta-regression models indicated that each alloplastic subtype significantly and independently predicted higher complications, while titanium and PMMA were significant predictors for all-cause failures compared to autologous bone. All three subtypes were predictive of higher cranioplasty failures secondary to infection compared to autologous bone. CONCLUSIONS: Cranioplasties performed with fresh, autologous heterotopic cranial bone grafts resulted in lower complications and failures compared to alloplastic materials.

Current Trends in Breast Reconstruction following Bilateral Prophylactic Mastectomy.

Background: Individuals with genetic susceptibility to breast cancer may pursue bilateral prophylactic mastectomy (BPM) and subsequent breast reconstruction. This study aimed to characterize immediate reconstructive trends following BPM. Methods: The ACS-NSQIP database (2010 -2019) was used to examine differences in demographics and operative outcomes based on breast reconstruction technique following BPM and factors predicting reconstruction type. Results: Of 1945 patients (mean age, 43.8 ± 11.3 years), implant-based reconstruction (IBR) was most frequently (71.8%) performed following BPM. Patients who underwent IBR (n = 1396) were younger (42.6 years, P < 0.001), more likely to be White (P < 0.05), and more likely to have a BMI less than 25 (P < 0.001). Patients who underwent autologous reconstruction (AR) (n = 186, 45.8 years) were more likely to be Black or African American and have a BMI of 25-30. Patients who underwent mastectomy only (MO) without immediate reconstruction (n = 363) were older (47.6 years), more likely to be Asian, and more likely to have a BMI greater than 35. The MO cohort had the highest frequency of diabetes or smoking history. AR was associated with longer operations, longer lengths of stay, and increased complications. Increasing age and BMI were predictive of AR or MO compared to IBR. Smoking was predictive of MO. Conclusion: This is the first large-scale study of genetically susceptible patients who underwent BPM demonstrating a significant relationship between patient demographics, operative outcomes, and immediate reconstruction technique. These results provide valuable insight for surgeons and patients during the shared decision-making process.

Procedures Never Explained in Textbooks: How to Correctly Convert a Closed-Suction Drain to a Closed-Gravity Drain, and How to Correctly Remove a Closed-Suction Drain Off Suction.

Objective: To describe a novel method to convert a closed-system suction drain to a highly efficient closed-system gravity-dependent drain and demonstrate its efficacy in an ex-vivo model. Methods: We reviewed the 5 top-selling urology and surgery text/reference books for information on drainage systems. An ex-vivo model was designed with a reservoir of fluid connected to a Jackson-Pratt bulb drain. We measured the volume of fluid drained from the reservoir into the bulb while on-suction and off-suction. This was repeated using a novel modified bulb, where the bulb's outflow stopper was replaced with a one-way valve oriented to allow release of pressure from the bulb. Results: With the bulb on-suction, drainage was maintained regardless of the height of the drain relative to the reservoir. With the bulb off-suction, closed passive gravity-dependent drainage occurred only when the drain was below the fluid reservoir; drainage ceased at minimal volumes. With addition of a one-way valve and maintenance of the bulb below the level of the reservoir, drainage proceeded to completion. Conclusion: How surgical drains work is not described in the leading urology and general surgery textbooks/reference books. Closed-system suction drains cannot be used to achieve passive gravity-dependent drainage without allowing release of displaced air from the bulb-lumen. The novel modified drain we describe affords reversible closed-system suction and passive drainage.

The utility of echocardiography in paediatric patients with musculoskeletal infections and bacteremia.

PURPOSE: The clinical utility of echocardiography in the setting of a positive blood culture in paediatric patients presenting with osteomyelitis (OM) and/or septic arthritis (SA). METHODS: Retrospective review between 2013 and 2019: Patients < 18 years with OM, SA or combined infection (OM+SA) were included. Patients were excluded for immunodeficiency, loss of follow-up or penetrating infection. Charts with positive blood cultures were reviewed for echocardiography on that admission. Demographic variables were compared utilizing the Student's t-test and Fisher's exact test. A multivariable linear regression model was constructed to examine the association between echocardiography and length of stay, controlling for age, sex, fever, white blood cell (WBC) on admission, antibiotic administration and surgery performed. RESULTS: Of 157 patients with OM, SA or combined infection, 44 had a positive blood culture. In all, 26 had an echocardiogram, and none showed endocarditis. Echocardiography was independently associated with a 6.2-day length of stay increase. WBC count and surgical intervention demonstrated a trend toward significance in length of stay, with each WBC unit increase associated with a 0.53-day increase. Surgical intervention was associated with an average 6.3-day length of stay decrease. CONCLUSION: No patient had a positive echocardiogram, and no changes in management were initiated. However, an echocardiogram increased stay by 6.2 days. In addition to costs associated with increased stay, patients were billed between $1460 and $1700 per echocardiogram. The utility of echocardiograms in the setting of bacteremia associated with musculoskeletal infections in the paediatric population should be re-examined, and guidelines should be updated to reflect the cost-benefit analysis. LEVEL OF EVIDENCE: III.

Lateral to medial fibro-adipogenic degeneration are greater in infraspinatus than supraspinatus following nerve and tendon injury of murine rotator cuff.

Small animal models of massive tears of the rotator cuff (RC) were introduced a decade ago and have been extensively used to study the pathophysiology of chronically injured RC. Transection of rodent suprascapular nerve and RC tendon results in progressive muscle atrophy, fibrosis and fat accumulation and affect the infraspinatus and supraspinatus muscles similarly to that seen in the setting of massive RC tears in humans. The purpose of this study was to perform a comprehensive and detailed analysis of the kinetics of fibrotic scar and adipose tissue development comparing phenotypic differences between chronically injured infraspinatus and supraspinatus. Automatic mosaic imaging was used to create large image of whole infraspinatus or supraspinatus sectioned area for quantification of spatial heterogeneity of muscle damage. Pathologic changes advanced from the lateral site of transection to the medial region far from the transection site. A prominent, accelerated muscle fibrosis and fat accumulation was measured in injured infraspinatus compared to supraspinatus. Furthermore, adipose tissue occupied significantly larger area than that of fibrotic tissue in both muscles but was greater in infraspinatus within 6 weeks post induction of injury. Our findings confirm that infraspinatus is more susceptible to accelerated chronic degeneration and can be used to identify the physiological functions that distinguish between the response of infraspinatus and supraspinatus in the setting of massive tears. Whether these pathologic differences observed in mice are reflected in humans is one key aspect that awaits clarification.

Aged Mice Demonstrate Greater Muscle Degeneration of Chronically Injured Rotator Cuff.

Massive tears of the rotator cuff (RC) are often associated with progressive and irreversible muscle degeneration due to fibrosis, fatty infiltration, and muscle atrophy. RC tears are common in individuals older than 60 years and the repair of these tears is amongst the most prevalent of orthopedic procedures. However, most current models of this injury are established in young animals, which may not accurately recapitulate the clinical condition. In this study, we used a murine model of massive RC tears to evaluate age-related muscle degeneration following chronic injury. The expression of the fibro-adipogenic genes encoding collagen type III and leptin was higher in aged RC compared with matched injured young tissue at 2 weeks post-injury, and development of fibrosis was accelerated in aged mice within 5 days post-injury. Furthermore, the synthesis of collagens type I and III and fat tissue accumulation were significantly higher in injured RCs of aged mice. Similar frequency of fibro-adipogenic PDGFRß+ PDGFRα+ progenitor cells was measured in non-injured RC of aged and young mice, but PDGFRß+ PDGFRα+ cells contributed to significantly larger fibrotic lesions in aged RCs within 2 weeks post-injury, implying a more robust fibrotic environment in the aged injured muscle. Altogether, these findings demonstrate age-dependent differences in RC response to chronic injury with a more profound fibro-adipogenic change in aged muscles. Clinically, cell therapies for muscular pathologies should not only consider the cell type being transplanted but also the recipient milieu into which these cells are seeded. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:320-328, 2020.

Medical text analytics tools for search and classification.

A text-analytic tool has been developed that accepts clinical medical data as input in order to produce patient details. The integrated tool has the following four characteristics. 1) It has a graphical user interface. 2) It has a free-text search tool that is designed to retrieve records using keywords such as "MI" for myocardial infarction. The result set is a display of those sentences in the medical records that contain the keywords. 3) It has three tools to classify patients based on the likelihood of being diagnosed for myocardial infarction, hypertension, or their smoking status. 4) A summary is generated for each patient selected. Large medical data sets provided by the Institute for Clinical Evaluative Sciences were used during the project.

Non-fibro-adipogenic pericytes from human embryonic stem cells attenuate degeneration of the chronically injured mouse muscle.

Massive tears of the rotator cuff (RC) are associated with chronic muscle degeneration due to fibrosis, fatty infiltration, and muscle atrophy. The microenvironment of diseased muscle often impairs efficient engraftment and regenerative activity of transplanted myogenic precursors. Accumulating myofibroblasts and fat cells disrupt the muscle stem cell niche and myogenic cell signaling and deposit excess disorganized connective tissue. Therefore, restoration of the damaged stromal niche with non-fibro-adipogenic cells is a prerequisite to successful repair of an injured RC. We generated from human embryonic stem cells (hES) a potentially novel subset of PDGFR-ß+CD146+CD34-CD56- pericytes that lack expression of the fibro-adipogenic cell marker PDGFR-α. Accordingly, the PDGFR-ß+PDGFR-α- phenotype typified non-fibro-adipogenic, non-myogenic, pericyte-like derivatives that maintained non-fibro-adipogenic properties when transplanted into chronically injured murine RCs. Although administered hES pericytes inhibited developing fibrosis at early and late stages of progressive muscle degeneration, transplanted PDGFR-ß+PDGFR-α+ human muscle-derived fibro-adipogenic progenitors contributed to adipogenesis and greater fibrosis. Additionally, transplanted hES pericytes substantially attenuated muscle atrophy at all tested injection time points after injury. Coinciding with this observation, conditioned medium from cultured hES pericytes rescued atrophic myotubes in vitro. These findings imply that non-fibro-adipogenic hES pericytes recapitulate the myogenic stromal niche and may be used to improve cell-based treatments for chronic muscle disorders.

Potential for the international spread of middle East respiratory syndrome in association with mass gatherings in saudi arabia.

BACKGROUND: A novel coronavirus (MERS-CoV) causing severe, life-threatening respiratory disease has emerged in the Middle East at a time when two international mass gatherings in Saudi Arabia are imminent. While MERS-CoV has already spread to and within other countries, these mass gatherings could further amplify and/or accelerate its international dissemination, especially since the origins and geographic source of the virus remain poorly understood. METHODS: We analyzed 2012 worldwide flight itinerary data and historic Hajj pilgrim data to predict population movements out of Saudi Arabia and the broader Middle East to help cities and countries assess their potential for MERS-CoV importation. We compared the magnitude of travel to countries with their World Bank economic status and per capita healthcare expenditures as surrogate markers of their capacity for timely detection of imported MERS-CoV and their ability to mount an effective public health response. RESULTS: 16.8 million travelers flew on commercial flights out of Saudi Arabia, Jordan, Qatar, and the United Arab Emirates between June and November 2012, of which 51.6% were destined for India (16.3%), Egypt (10.4%), Pakistan (7.8%), the United Kingdom (4.3%), Kuwait (3.6%), Bangladesh (3.1%), Iran (3.1%) and Bahrain (2.9%). Among the 1.74 million foreign pilgrims who performed the Hajj last year, an estimated 65.1% originated from low and lower-middle income countries. CONCLUSION: MERS-CoV is an emerging pathogen with pandemic potential with its apparent epicenter in Saudi Arabia, where millions of pilgrims will imminently congregate for two international mass gatherings. Understanding global population movements out of the Middle East through the end of this year's Hajj could help direct anticipatory MERS-CoV surveillance and public health preparedness to mitigate its potential global health and economic impacts.

Decrease in bladder overactivity with REN1820 in rats with cyclophosphamide induced cystitis.

PURPOSE: Studies suggest that nerve growth factor (NGF) contributes to bladder overactivity stemming from bladder inflammation. Studies were performed to determine the NGF dependence of cyclophosphamide (CYP) induced changes in bladder function using the recombinant NGF sequestering protein REN1820. MATERIALS AND METHODS: Urodynamic testing and behavioral observations were made in female rats treated with CYP (4 or 48 hours) and REN1820 or vehicle. RESULTS: Rats examined 4 or 48 hours after CYP treatment plus REN1820 showed significantly fewer nonvoiding contractions with smaller amplitude (p

A mechanogated nonselective cation channel in proximal tubule that is ATP sensitive.

Ion channels that are gated in response to membrane deformation or "stretch" are empirically designated stretch-activated channels. Here we describe a stretch-activated nonselective cation channel in the basolateral membrane (BLM) of the proximal tubule (PT) that is nucleotide sensitive. Single channels were studied in cell-intact and cell-free patches from the BLM of PT cells that maintain their epithelial polarity. The limiting inward Cs+ conductance is ~28 pS, and channel activity persists after excision into a Ca2+- and ATP-free bath. The stretch-dose response is sigmoidal, with half-maximal activation of about -19 mmHg at -40 mV, and the channel is activated by depolarization. The inward conductance sequence is: NH ~ Cs+ ~ Rb+ > K+ ~ Na+ ~ Li+ > Ca2+ ~ Ba2+ > N-methyl-D-glucamine ~ tetraethylammonium. The venom of the common Chilean tarantula, Grammostola spatulata, completely blocks channel activity in cell-attached patches. Hypotonic swelling reversibly activates the channel. Intracellular ATP concentration ([ATP]i) reversibly blocks the channel (inhibitory constant approximately 0.48 mM), suggesting that channel function is coupled to the metabolic state of the cell. We conclude that this channel may function as a Ca2+ entry pathway and/or be involved in regulation of cell volume. We speculate this channel may be important when [ATP]i is depleted, as occurs during periods of increased transepithelial transport or with ischemic injury.

Cyclophosphamide induced cystitis alters neurotrophin and receptor tyrosine kinase expression in pelvic ganglia and bladder.

PURPOSE: We examined neurotrophin and receptor tyrosine kinase (Trk) expression in the bladder and major pelvic ganglia (MPG) after cyclophosphamide induced cystitis in rats. MATERIALS AND METHODS: The bladder and MPG were used in immunohistochemical studies, enzyme-linked immunoassays and Western blots for nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), TrkA and TrkB. Bladder postganglionic MPG cells were labeled by tracing techniques. RESULTS: NGF and BDNF expression was decreased in the bladder of all rats after cystitis (p < or =0.001). NGF and BDNF expression was increased in the MPG in male rats with cystitis (p < or =0.01). Cells expressing TrkA and TrkB immunoreactivity (IR) increased 78% to 81% in the MPG in male rats with cystitis. TrkA-IR or TrkB-IR bladder postganglionic cells increased 50% to 74% with cystitis. Cystitis increased TrkA-IR 5 to 10-fold and TrkB-IR 10 to 12-fold in detrusor muscle. TrkA-IR and TrkB-IR were prominent in control urothelium but decreased with cystitis. After cystitis TrkB-IR nerve fibers and TrkA-IR cellular infiltrates were more apparent compared to controls. CONCLUSIONS: Cystitis decreases bladder NGF and BDNF expression, whereas MPG expression is increased. This change may reflect neurotrophin release at the bladder and retrograde transport to the MPG. TrkA-IR and TrkB-IR are increased in bladder postganglionic cells and bladders with cystitis. This increase may reflect a shift in Trk staining from urothelium to detrusor muscle and nerve fibers with cystitis. Neurotrophin/Trk interactions in the bladder and MPG may contribute to bladder overactivity with cystitis.