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INTRODUCTION: Knee dislocations (KD) have high rates of multi-ligamentous injury (MLI). Collateral ligaments rupture in 50-60% of KDs. Traditionally, collateral ligaments have undergone primary repair, though microscopic healing is not optimal. Artelon is a degradable, polyurethane urea bio- scaffold thought to decrease mechanical forces and promote healing, motion, and strength. Currently, little evidence exists regarding its indications or outcomes. MATERIALS AND METHODS: Thirty-two patients with KD and MLI undergoing collateral ligament repair at a level-I trauma centre between 2015-2020 were included. Patients age 15° of knee flexion. Only one gross failure occurred, in the AG. No differences were noted in infection or re-operation. Lysholm Knee Scale and Tegner Activity Scale were not significantly different, although Tegner scores in both cohorts decreased from pre-injury scores. CONCLUSION: In summary, Artelon appears to be safe without increasing risk for hypersensitivity or infection when used for collateral ligament augmentation. Additionally, Artelon appeared to be non-inferior and statistically equivalent to primary repair in this setting and may have promise with use in certain types of knee dislocations.

The polariton-polariton interaction strength is an important parameter for all kinds of applications using the nonlinear properties of polaritons, such as optical switching and single-photon blockade devices. In this paper, we review and compare the results of a series of experiments on polariton-polariton interactions in GaAs/AlxGa1-xAs microcavity polariton structures and present an updated analysis of these experiments. We show that not just the energy shift of the spectral lines but also the results of measurements sensitive to the polariton scattering rate are important for the calibration of the interaction parameter at low excitation density. We find that when adjustments are made to correct for recent understanding of the experiments, the value of the interaction parameter at low density is lower than previous reported, but still significantly higher than theoretically predicted.

Background: The diagnosis of infectious flexor tenosynovitis (FTS) has historically been made based on physical exam using Kanavel's signs. The specificity of these findings has come into question. We looked to evaluate the use of contrast-enhanced computed tomography (CT) in increasing the successful diagnosis of FTS., Methods: Two adult cohorts were formed, one of patients with FTS confirmed in the operating room and the second of patients with ICD.10 identified finger cellulitis (FC), without concomitant FTS. Demographics, laboratory values, CT scans, and examination findings were evaluated. Axial CTs were evaluated in the coronal and sagittal planes and tendon sheath/tendon width were measured. The tendon sheath/tendon was recorded as a ratio in the coronal (CR) and sagittal (SR) planes. Continuous and dichotomous variables were analyzed and measures of sensitivity, specificity, and predictivity were calculated. Seventy patients were included, 35 in the FTS cohort and 35 with FC., Result: A higher number of Kanavel signs were present in the FTS group (2.9 vs. 0.5, P < .05), with CR and SR both being significantly larger in the FTS group ( P < .05). CR and SR cutoffs ≥ 1.3 provided high sensitivity, specificity, and positive predictive value (PPV) for FTS. Likelihood of FTS increased 5.9% and 5.5% for every 0.1 increase in CR and SR, respectively, with a 14% increase for every additional Kanavel sign., Conclusion: In conclusion, CT ratios are useful in identifying FTS; and when used on their own or in combination with Kanavel's signs, CR and SR objectively improve the diagnosis of FTS., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: BT receives payments from ZimmerBiomet, Atricure, and Temple University. In addition to these he also has a relationship with Orthobullets.com. None of these are relevant to this manuscript. The remaining authors do not have any disclosures of a conflict of interest.

The white sturgeon (Acipenser transmontanus) is the largest freshwater fish in North America. Because of the unique life history characteristics of sturgeon, including longevity, late maturation and long spawning intervals, their aquaculture can be a significant investment of resources. As a result of habitat loss and overharvesting, natural populations of white sturgeon are threatened and there is a growing effort to improve conservation aquaculture programs. Germ cell transplantation is an innovative technology previously demonstrated in a variety of fish species to be able to produce a surrogate broodstock. The technique relies upon optimal donor germ cell recovery and transplantation into a recipient fish. In this study, we developed and optimized the harvest of donor cells for germline transplantation and evaluated methods for ovary cryopreservation for the first time in the white sturgeon. We found that harvesting gonads from juveniles between the ages of 1.5 and 2.5-years resulted in reliably high proportions of pre-meiotic cells regardless of sex, a critical feature for using white sturgeon for transplantation studies since the species shows no distinguishing external sex characteristics. From the viable cells, we identified germline cells using immunolabeling with the antibody DDX4, a marker specific to the germline. For in vivo tracking of donor cells during transplantations, gonadal cells were stained with a long half-life non-toxic cell membrane dye, PKH26, and microinjected into the peritoneal cavity of newly hatched white sturgeon larvae. Larvae were reared until 3 months post-transplantation to monitor for colonization and proliferation of PKH26-labeled cells within the recipient larval gonads. Furthermore, viable cell detection, assessment of germline-specificity, and transplantation was determined for cells recovered from cryopreserved ovarian tissue from sexually immature females. Transplantations using cells cryopreserved with media supplemented with dimethyl sulfoxide (DMSO) rather than ethylene glycol (EG) demonstrated the highest number of PKH26-labeled cells distributed along the gonadal ridges of the larval recipient. Determining optimal methods of tissue cryopreservation, and germ cell recovery and transplantation are foundational to the future development of germ cell transplantation as a strategy to improve the aquaculture and conservation of this species. Our study demonstrates that conservation actions, such as surrogate breeding, could be utilized by hatcheries to retain or improve natural gamete production without genetic modification, and provide an encouraging approach to the management of threatened sturgeon species., (© 2023. Springer Nature Limited.)

The traditional method of treating fibular fractures in unstable ankle injuries involves open reduction and internal fixation with a plate and screw construct. Less invasive percutaneous fixation techniques with intramedullary fibular screws have been utilized for many years to reduce wound and implant complications while maintaining a stable ankle mortise. However, there have been no direct case-control studies comparing percutaneous intramedullary fibular screw fixation to the traditional open reduction and internal fixation with plates and screws. In our study, we compared radiographic and clinical outcomes for unstable ankle fractures in which the fibula fracture was treated with either a percutaneous intramedullary screw or by open reduction and internal fixation with a plate and screw construct. We retrospectively reviewed 69 consecutive patients from 2011 to 2019 with unstable ankle fractures treated with intramedullary fibular screws and compared them to 216 case-control patients treated with traditional plate and screw construct over the same time period. The average follow-up for the intramedullary screw group was 11.5 months and 15.2 months for the plate and screw group. We collected general demographic data, measured intraoperative and final follow-up talocrural angles, Kellgren-Lawrence osteoarthritis grade, union rates, implant removal rates, infection rates, and American Orthopedic Foot and Ankle Society ankle-hindfoot scores. The intramedullary screw group had a statistically significant lower rate of delayed implant removal (8.7% vs 23.6%) and there was no detectable difference in other measures., (Copyright © 2022 the American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

Methods of fixation in ankle fractures involving the posterior malleolus have become increasingly scrutinized. With the increase in computed tomography (CT), an intercalary fracture fragment (ICF) adjacent to the posterior malleolus has been oft described. Treatment of the ICF remains controversial and the purpose of this study was to evaluate radiographic and clinical outcomes in patients who had direct reduction and fixation of this fragment compared to those where the ICF was not fixed. This retrospective study included 249 trimalleolar and posterior pilon ankle fractures grouped into those who had the ICF reduced and fixed (n = 74) and those where the ICF was not directly addressed (n = 175). CT scans were evaluated for size and location of the ICF. Demographic, radiographic and intraoperative variables were collected and analyzed. The group which had the ICF reduced and fixed had decreased Kellgren-Lawrence scores (p = .001). There was also a higher rate of repeat surgery in the group who had the ICF fixed, although not meeting statistical significance. There were no differences in size or location of the ICF fragment between groups. We did identify similarities with other studies in regard to size and posterolateral location of the ICF between groups. However, based on worsening radiographic outcomes of the group where the ICF was reduced and fixed, we do not necessarily recommend universal treatment of this fragment. The surgeon's goal should always be a concentric articular reduction and treatment of the ICF should be considered on a case-by-case basis., (Copyright © 2022 the American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

Intramedullary nailing of femur fractures has become the standard of care, with high union rates. Few high-level studies have discussed the effect that early weight bearing has on the healing of these fractures, regardless of nail size or fracture pattern. The goal of this study was to determine the clinical and radiographic outcomes of femoral shaft fractures for patients allowed immediate weight bearing after intramedullary nailing. We performed a retrospective review of 341 femoral shaft fractures, with 131 allowed immediate weight bearing, 99 allowed partial weight bearing, and 111 kept non-weight bearing. Demographic, intraoperative, and postoperative variables were collected and analyzed. Increased fracture complexity was associated with higher likelihood of delayed weight bearing. No significant difference was found for nail size or rate of failure with different nail sizes. A total of 50 nonunions were noted (14.7%), with no difference in nonunion rates between weight bearing cohorts. The only significant predictor of nonunion was Orthopaedic Trauma Association (OTA) classification of OTA32B fractures ( P =.02), which were 2 times and 4 times as likely to occur compared with OTA32A and OTA32C fractures, respectively. Failure of interlocking screws occurred among 15 patients (4.4%) and was more common with older patients, osteoporotic bone, and larger diameter nails. In summary, unilateral intramedullary nailing of adult femoral shaft fractures does not show a difference in fracture union rates or implant failure with unrestricted, immediate weight bearing, regardless of nail characteristics. [ Orthopedics . 2022;45(3):e148-e153.].

Significance: Deranged metabolism and dysregulated growth factor signaling are closely associated with abnormal levels of proliferation, a recognized hallmark in tumorigenesis. Fluorescence lifetime imaging microscopy (FLIM) of endogenous nicotinamide adenine dinucleotide (NADH), a key metabolic coenzyme, offers a non-invasive, diagnostic indicator of disease progression, and treatment response. The model-independent phasor analysis approach leverages FLIM to rapidly evaluate cancer metabolism in response to targeted therapy., Aim: We combined lifetime and phasor FLIM analysis to evaluate the influence of human epidermal growth factor receptor 2 (HER2) inhibition, a prevalent cancer biomarker, on both nuclear and cytoplasmic NAD(P)H of two squamous cell carcinoma (SCC) cultures. While better established, the standard lifetime analysis approach is relatively slow and potentially subject to intrinsic fitting errors and model assumptions. Phasor FLIM analysis offers a rapid, model-independent alternative, but the sensitivity of the bound NAD(P)H fraction to growth factor signaling must also be firmly established., Approach: Two SCC cultures with low- and high-HER2 expression, were imaged using multiphoton-excited NAD(P)H FLIM, with and without treatment of the HER2 inhibitor AG825. Cells were challenged with mitochondrial inhibition and uncoupling to investigate AG825's impact on the overall metabolic capacity. Phasor FLIM and lifetime fitting analyses were compared within nuclear and cytoplasmic compartments to investigate epigenetic and metabolic impacts of HER2 inhibition., Results: NAD(P)H fluorescence lifetime and bound fraction consistently decreased following HER2 inhibition in both cell lines. High-HER2 SCC74B cells displayed a more significant response than low-HER2 SCC74A in both techniques. HER2 inhibition induced greater changes in nuclear than cytoplasmic compartments, leading to an increase in NAD(P)H intensity and concentration., Conclusions: The use of both, complementary FLIM analysis techniques together with quantitative fluorescence intensity revealed consistent, quantitative changes in NAD(P)H metabolism associated with inhibition of growth factor signaling in SCC cell lines. HER2 inhibition promoted increased reliance on oxidative phosphorylation in both cell lines.

Current practice allows early weight bearing of unstable ankle fractures after fixation. This study offers a unique comparison of early weight bearing (EWB) vs late weight bearing (LWB) in operatively stabilized trimalleolar ankle fractures. The goal of this study was to evaluate union rates, clinical outcomes, and complications for patients who were managed with EWB vs LWB. The authors performed a retrospective review of 185 patients who underwent surgical stabilization for trimalleolar ankle fracture. Fixation of the posterior malleolus and weight bearing status were determined by surgeon preference. For this study, EWB was defined as 3 weeks or less and LWB was defined as greater than 3 weeks. Patients were evaluated for fracture union and implant failure. Complications and clinical outcomes included ambulatory status, infection rate, and return to surgery. The EWB group included 47 (25.4%) patients, and the LWB group included 138 (74.6%) patients. Of the 7 nonunions, 1 (14.3%) occurred in the EWB group and 6 (85.7%) in the LWB group. A total of 72 (38.9%) posterior malleolar fractures were operatively stabilized, and stabilization did not affect union rates. Syndesmotic fixation was required for 12.5% of patients, despite posterior malleolar stabilization. Syndesmotic fixation increased the union rate 2.5 times. Deep infection and open fracture decreased union. No difference was seen between groups in implant failure, union rate, infection, or return to the operating room. No deleterious effect of EWB in operatively treated trimalleolar ankle fractures was found for union, implant failure, infection, or reoperation. Syndesmotic fixation may offer an advantage over posterior malleolar fixation, with improved union rates. [ Orthopedics . 2021;44(3):160-165.].

Introduction: High rates of morbidity and mortality following flail chest rib fractures are well publicized. Standard of care has been supportive mechanical ventilation, but serious complications have been reported. Internal rib fixation has shown improvements in pulmonary function, clinical outcomes, and decreased mortality. The goal of this study was to provide a model defining the biomechanical benefits of internal rib fixation., Methods: One human cadaver was prepared with an actuator providing anteroposterior forces to the thorax and rib motion sensors to define interfragmentary motion. Cadaveric model was validated using a prior study which defined costovertebral motion to create a protocol using similar technology and procedure. Ribs 4-6 were fixed with motion sensors anteriorly, laterally and posteriorly. Motion was recorded with ribs intact before osteotomizing each rib anteriorly and laterally. Flail chest motion was record with fractures subsequently plated and analyzed. Motion was recorded in the sagittal, coronal and transverse axes., Findings: Compared to the intact rib model, the flail chest model demonstrated an 11.3 times increase in sagittal plane motion, which was reduced to 2.1 times the intact model with rib plating. Coronal and sagittal plane models also saw increases of 9.7 and 5.1 times, respectively, with regards to flail chest motion. Both were reduced to 1.2 times the intact model after rib plating., Interpretation: This study allows quantification of altered ribcage biomechanics after flail chest injuries and suggests rib plating is useful in restoring biomechanics as well as contributing to improving pulmonary function and clinical outcomes., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Proximal humerus fractures, although common, have high rates of failure after open reduction and internal fixation. The use of a fibular allograft has been explored as a means to decrease complications, particularly varus collapse and the need for revision surgery. The authors performed a retrospective review of 133 proximal humerus fractures managed surgically with locking plates (n=72) or locking plates with fibular allograft intramedullary struts (n=61). Demographic, intraoperative, and postoperative variables were collected and analyzed. The fibular allograft group was more likely to be older (P<.01), be female (P=.04), and have a history of osteoporosis (P=.01). No differences were noted in the proportions of 2-, 3-, or 4-part fractures between groups. Average follow-up was 28 weeks. Medial calcar length was longer in the locking plate only group (P=.04); however, this group demonstrated a decreased head shaft angle (P=.01) and a trend toward increased rates of varus collapse (P=.06). No significant differences were found regarding other radiographic complications, irrespective of fracture complexity. A notable decrease in fluoroscopy time was seen with strut use (P=.04), but operative time and blood loss were similar between groups. A significant decrease in revision surgery rate was found with use of an allograft strut (P=.05). Using a strut appears to preserve the radiographic head shaft angle and decrease the risk of fracture collapse in 2-, 3-, and 4-part fractures, without increasing surgical time or morbidity. Use of an intramedullary strut appears to reduce the need for revision surgery, particularly in 3- and 4-part fractures. [Orthopedics. 2020;43(5):262-268.]., (Copyright 2020, SLACK Incorporated.)

Ankle fractures are common orthopedic injuries. Although operative indications and subsequent stabilization of these fractures have not significantly changed, postoperative protocols remain highly variable. Effects of early weight bearing (EWB) on fracture characteristics in operatively stabilized bimalleolar and bimalleolar equivalent ankle fractures remain poorly publicized. This study seeks to clarify postoperative fracture union rates, rates of hardware loosening or failure, and radiographic medial clear space changes when comparing EWB to late weight bearing (LWB) following open reduction and internal fixation (ORIF). A total of 95 patients with either bimalleolar (66%) or bimalleolar equivalent (34%) fractures who underwent ORIF were retrospectively reviewed. Weight bearing was allowed at three weeks in the EWB group and when signs of radiographic union were noted in the LWB group. Postoperatively, patients were evaluated at regular intervals for fracture union, signs of implant failure, and evidence of medial clear space widening radiographically. There were 38 patients (40%) in the EWB group and 57 patients (60%) comprising the LWB cohort. There were no significant demographic differences between groups. The EWB group on average began to weight bear at 3.1 + 1.4 weeks postoperatively, whereas the LWB group began at 7.2 + 2.1 weeks postoperatively (p<0.01). Union rate (p=0.51), time to union (p=0.23), and implant failure (p>0.1 at all time intervals) were not notably different between groups. No differences in medial clear space were detected at any postoperative interval between groups (p>0.1 at all time intervals). This study suggests that EWB at three weeks postoperatively does not increase markers of radiographic failure compared to six weeks of non-weight bearing (NWB), which has been regarded as the gold standard of treatment to allow for healing; this may represent an improvement to rehabilitation protocols after bimalleolar ankle ORIF of unstable ankle fractures., Competing Interests: The authors have declared financial relationships, which are detailed in the next section., (Copyright © 2020, Passias et al.)

Operative treatment of quadriceps and patellar tendon ruptures with transosseous bone tunnels remains the gold standard, but potential benefits exist with the use of suture anchor fixation for these injuries. Such benefits include stronger biomechanical fixation, reduced soft-tissue disruption, smaller incision, reduced postoperative pain, shorter operative time, lower knot burden, lack of prepatellar bursa scarring, and avoidance of some transosseous repair risks. In this investigation, we present the reproducible technique and outcomes of using suture anchors for repair of quadriceps and patellar tendon ruptures.

Background: The incidence of posttraumatic arthrosis after acetabular fractures is significant, and patients frequently require secondary total hip arthroplasty. Conversion arthroplasty is more technically difficult, and there is higher risk than with routine primary total hip arthroplasty. The goal of this study was to identify the challenges and risks of secondary total hip arthroplasty compared to primary total hip arthroplasty., Methods: We retrospectively identified 30 patients who underwent secondary total hip arthroplasty after open reduction and internal fixation of an acetabulum fracture and compared them with 20 patients who had undergone primary total hip arthroplasty for degenerative joint disease., Results: Demographic data were similar between groups. Hardware removal was deemed necessary in 21 patients (70%). Allograft was needed for bone defects in 33% of secondary total hip arthroplasty cases, while no primary cases required grafting. Operative time (217.4 vs. 113.7 min, P < 0.01) and estimated blood loss (875.8 vs. 365 mL, P < 0.01) were significantly greater in the secondary arthroplasty group. Early postoperative complications were also higher in the secondary arthroplasty group., Conclusions: Total hip arthroplasty after acetabular fracture open reduction and internal fixation is a more complex procedure due to exposure difficulty, possible implant removal, management of bony deficits, and the potential use of cages and revision components. Experienced surgeons managing these complicated cases must take great care not only in ensuring appropriate technique but also in appropriate patient education regarding increased risk of major and minor complications., Level of Evidence: Level III.

Background: Genome-wide association studies have implicated variants in SCN10A, which encodes Nav1.8, as modulators of cardiac conduction. Follow-up work has indicated the SCN10A sequence includes an intronic enhancer for SCN5A. Yet the role of the Nav1.8 protein in the myocardium itself is still unclear. To investigate this, we use homozygous knockout mice (Scn10a -/- ) generated by disruption of exons 4 and 5, leaving the Scn5a enhancer intact., Methods and Results: We previously reported that pharmacologic blockade of Nav1.8 in wild-type animals blunts action potential prolongation by ATX-II at slow drive rates (≤1 Hz). Here we present evidence of the same blunting in Scn10a -/- compared to wild-type ventricular myocytes, supporting the conclusion that Nav1.8 contributes to late sodium current at slow rates. In contrast to earlier studies, we found no differences in electrocardiographic parameters between genotypes. Low-dose ATX-II exposure in lightly anesthetized animals and Langendorff-perfused hearts prolonged QTc and generated arrhythmias to the same extent in wild-type and Scn10a -/- . RNA sequencing failed to identify full-length Scn10a transcripts in wild-type or knockout isolated ventricular myocytes. However, loss of late current in Scn10a -/- myocytes was replicated independently in a blinded set of experiments., Conclusions: While Scn10a transcripts are not detectible in ventricular cardiomyocytes, gene deletion results in reproducible loss of late sodium current under extreme experimental conditions. However, there are no identifiable consequences of this Scn10a deletion in the intact mouse heart at usual rates. These findings argue that common variants in SCN10A that affect ventricular conduction do so by modulating SCN5A., (© 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.)

Aims: Female gender is a risk factor for long QT-related arrhythmias, but the underlying mechanisms remain uncertain. Here, we tested the hypothesis that gender-dependent function of the post-depolarization 'late' sodium current (I(Na-L)) contributes., Methods and Results: Studies were conducted in mice in which the canonical cardiac sodium channel Scn5a locus was disrupted, and expression of human wild-type SCN5A cDNA substituted. Baseline QT intervals were similar in male and female mice, but exposure to the sodium channel opener anemone toxin ATX-II elicited polymorphic ventricular tachycardia in 0/9 males vs. 6/9 females. Ventricular I(Na-L) and action potential durations were increased in myocytes isolated from female mice compared with those from males before and especially after treatment with ATX-II. Further, ATX-II elicited potentially arrhythmogenic early afterdepolarizations in myocytes from 0/5 male mice and 3/5 female mice., Conclusion: These data identify variable late I(Na) as a modulator of gender-dependent arrhythmia susceptibility.

Rationale: Although the sodium channel locus SCN10A has been implicated by genome-wide association studies as a modulator of cardiac electrophysiology, the role of its gene product Nav1.8 as a modulator of cardiac ion currents is unknown., Objective: We determined the electrophysiological and pharmacological properties of Nav1.8 in heterologous cell systems and assessed the antiarrhythmic effect of Nav1.8 block on isolated mouse and rabbit ventricular cardiomyocytes., Methods and Results: We first demonstrated that Scn10a transcripts are identified in mouse heart and that the blocker A-803467 is highly specific for Nav1.8 current over that of Nav1.5, the canonical cardiac sodium channel encoded by SCN5A. We then showed that low concentrations of A-803467 selectively block "late" sodium current and shorten action potentials in mouse and rabbit cardiomyocytes. Exaggerated late sodium current is known to mediate arrhythmogenic early afterdepolarizations in heart, and these were similarly suppressed by low concentrations of A-803467., Conclusions: Scn10a expression contributes to late sodium current in heart and represents a new target for antiarrhythmic intervention.

Mutations in the presenilin 1 (PS1) gene lead to early-onset Alzheimer's disease with the S170F mutation causing the earliest reported age of onset. Expression of this, and other PS1 mutations, in SH-SY5Y cells resulted in significant loss of cellular viability compared to control cells. Basal Ca2+ concentrations in PS1 mutants were never lower than controls and prolonged incubation in Ca2+ -free solutions did not deplete Ca2+ stores, demonstrating there was no difference in Ca2+ leak from endoplasmic reticulum (ER) stores in PS1 mutants. Peak muscarine-evoked rises of [Ca2+]i were variable, but the integrals were not significantly different, suggesting, while kinetics of Ca2+ store release might be affected in PS1 mutants, store size was similar. However, when Ca2+ -ATPase activity was irreversibly inhibited with thapsigargin, the S170F and ΔE9 cells showed larger capacitative calcium entry indicating a direct effect on Ca2+ influx pathways. There was no significant effect of any of the mutations on mitochondrial respiration. Amyloid β(Aβ(1-40)) secretion was reduced, and Aβ(1-42) secretion increased in the S170F cells resulting in a very large increase in the Aβ42/40 ratio. This, rather than any potential disruption of ER Ca2+ stores, is likely to explain the extreme pathology of this mutant., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Background: The D1275N SCN5A mutation has been associated with a range of unusual phenotypes, including conduction disease and dilated cardiomyopathy, as well as atrial and ventricular tachyarrhythmias. However, when D1275N is studied in heterologous expression systems, most studies show near-normal sodium channel function. Thus, the relationship of the variant to the clinical phenotypes remains uncertain., Methods and Results: We identified D1275N in a patient with atrial flutter, atrial standstill, conduction disease, and sinus node dysfunction. There was no major difference in biophysical properties between wild-type and D1275N channels expressed in Chinese hamster ovary cells or tsA201 cells in the absence or presence of β1 subunits. To determine D1275N function in vivo, the Scn5a locus was modified to knock out the mouse gene, and the full-length wild-type (H) or D1275N (DN) human SCN5A cDNAs were then inserted at the modified locus by recombinase mediated cassette exchange. Mice carrying the DN allele displayed slow conduction, heart block, atrial fibrillation, ventricular tachycardia, and a dilated cardiomyopathy phenotype, with no significant fibrosis or myocyte disarray on histological examination. The DN allele conferred gene-dose-dependent increases in SCN5A mRNA abundance but reduced sodium channel protein abundance and peak sodium current amplitudes (H/H, 41.0±2.9 pA/pF at -30 mV; DN/H, 19.2±3.1 pA/pF, P<0.001 vs. H/H; DN/DN, 9.3±1.1 pA/pF, P<0.001 versus H/H)., Conclusions: Although D1275N produces near-normal currents in multiple heterologous expression experiments, our data establish this variant as a pathological mutation that generates conduction slowing, arrhythmias, and a dilated cardiomyopathy phenotype by reducing cardiac sodium current.

Rationale: Although multiple lines of evidence suggest that variable expression of the cardiac sodium channel gene SCN5A plays a role in susceptibility to arrhythmia, little is known about its transcriptional regulation., Objective: We used in silico and in vitro experiments to identify possible noncoding sequences important for transcriptional regulation of SCN5A. The results were extended to mice in which a putative regulatory region was deleted., Methods and Results: We identified 92 noncoding regions highly conserved (>70%) between human and mouse SCN5A orthologs. Three conserved noncoding sequences (CNS) showed significant (>5-fold) activity in luciferase assays. Further in vitro studies indicated one, CNS28 in intron 1, as a potential regulatory region. Using recombinase-mediated cassette exchange (RMCE), we generated mice in which a 435-base pair region encompassing CNS28 was removed. Animals homozygous for the deletion showed significant increases in SCN5A transcripts, Na(V)1.5 protein abundance, and sodium current measured in isolated ventricular myocytes. ECGs revealed a significantly shorter QRS (10.7±0.2 ms in controls versus 9.7±0.2 ms in knockouts), indicating more rapid ventricular conduction. In vitro analysis of CNS28 identified a short 3' segment within this region required for regulatory activity and including an E-box motif. Deletion of this segment reduced reporter activity to 3.6%±0.3% of baseline in CHO cells and 16%±3% in myocytes (both P<0.05), and mutation of individual sites in the E-box restored activity to 62%±4% and 57%±2% of baseline in CHO cells and myocytes, respectively (both P<0.05)., Conclusions: These findings establish that regulation of cardiac sodium channel expression modulates channel function in vivo, and identify a noncoding region underlying this regulation.

Rationale: Voltage-gated sodium channels initiate action potentials in excitable tissues. Mice in which Scn5A (the predominant sodium channel gene in heart) has been knocked out die early in development with cardiac malformations by mechanisms which have yet to be determined., Objective: Here we addressed this question by investigating the role of cardiac sodium channels in zebrafish heart development., Methods and Results: Transcripts of the functionally-conserved Scn5a homologs scn5Laa and scn5Lab were detected in the gastrulating zebrafish embryo and subsequently in the embryonic myocardium. Antisense knockdown of either channel resulted in marked cardiac chamber dysmorphogenesis and perturbed looping. These abnormalities were associated with decreased expression of the myocardial precursor genes nkx2.5, gata4, and hand2 in anterior lateral mesoderm and significant deficits in the production of cardiomyocyte progenitors. These early defects did not appear to result from altered membrane electrophysiology, as prolonged pharmacological blockade of sodium current failed to phenocopy channel knockdown. Moreover, embryos grown in calcium channel blocker-containing medium had hearts that did not beat but developed normally., Conclusions: These findings identify a novel and possibly nonelectrogenic role for cardiac sodium channels in heart development.

Social workers in diverse community practice settings recruit and work with volunteers from religious congregations. This article reports findings from two surveys: 7,405 congregants in 35 Protestant congregations, including 2,570 who were actively volunteering, and a follow-up survey of 946 volunteers. It compares characteristics of congregation volunteers and nonvolunteers.Volunteers tended to be married, older, more highly educated, longer-term congregational members, and to score higher on all measures of faith maturity and faith practice than did nonvolunteers.Volunteers perceived their involvement as meaningful, important, and challenging. A large majority of volunteers (80 percent) reported changes in faith, attitudes and values, and behavior as results of their volunteer work. Findings provide insights into how religious individuals begin and continue to volunteer in service settings and how congregations promote high levels of community service among their members. These findings have implications for effective social work practice with congregation volunteers.

Three groups of beef cow and calf pairs were studied to determine plasma vitamin E and blood selenium (Se) concentrations of calves at 1 month old. Group 1 was managed on irrigated pasture and calves received no Se/vitamin E injections at birth. Group 2 was managed on irrigated pasture, and the calves were injected with Se/vitamin E at birth. Group 3 was managed on dry foothill grasslands, and these cows were supplemented with 56.3 mg vitamin E and 3 mg Se daily, and the calves received a Se/vitamin E injection at birth. The plasma concentration of vitamin E in group 1 and 2 cows (9.5 +/- 1.24 and 8.43 +/- 1.0 microg/ml, respectively) was significantly higher than that of the group 3 cows (2.28 +/- 0.42 microg/ml; P < 0.05). The blood Se concentrations in group 3 cows (169 +/- 37 ng/ml) were significantly higher than those in group 1 and 2 cows (36.4 +/- 15.9 and 31.1 +/- 12.5 ng/ml, respectively; P < 0.05). Calf Se was highly correlated to cow Se (r = 0.965), and calf vitamin E was moderately correlated to cow vitamin E (r = 0.605). Calf vitamin E concentrations were consistently lower than cow vitamin E concentrations, and many values would be considered deficient.

Background: The atrioventricular (AV) node is essential for the sequential excitation and optimized contraction of the adult multichambered heart; however, relatively little is known about its formation from the embryonic AV canal. A recent study demonstrated that signaling by Alk3, the type 1a receptor for bone morphogenetic proteins, in the myocardium of the AV canal was required for the development of both the AV valves and annulus fibrosus. To test the hypothesis that bone morphogenetic protein signaling also plays a role in AV node formation, we investigated conduction system function and AV node morphology in adult mice with conditional deletion of Alk3 in the AV canal., Methods and Results: High-resolution optical mapping with correlative histological analysis of 28 mutant hearts revealed 4 basic phenotypic classes based on electrical activation patterns and volume-conducted ECGs. The frequency of AV node conduction and morphological abnormalities increased from no detectable anomalies (class I) to severe defects (class IV), which included the presence of bypass tracts, abnormal ventricular activation patterns, fibrosis of the AV node, and twin AV nodes., Conclusions: The present findings demonstrate that bone morphogenetic protein signaling is required in the myocardium of the AV canal for proper AV junction development, including the AV node.

A 65-year-old woman developed a watery diarrhea syndrome with collagenous colitis. Later, weight loss and hypoalbuminemia were documented. This prompted small bowel biopsies that showed pathological changes of collagenous sprue. An apparent treatment response to a gluten-free diet and prednisone resulted in reduced diarrhea, weight gain and normalization of serum albumin. Later repeated biopsies from multiple small and large bowel sites over a period of over three years, however, showed reversion to normal small intestinal mucosa but persistent collagenous colitis. These results indicate that collagenous inflammatory disease may be a far more extensive process in the gastrointestinal tract than is currently appreciated. Moreover, collagenous colitis may be a clinical signal that occult small intestinal disease is present. Finally, collagenous sprue may, in some instances, be a completely reversible small intestinal disorder.

This study assessed the effectiveness of a model for diffusing the Life Skills Training (LST) Program into middle schools, examined implementation fidelity, and explored factors associated with involvement in training and program implementation. A convenience sample of master trainers (n = 44) and teachers (n = 45) from 16 Kentucky counties participated. Teachers were observed for content and process fidelity, and trainers and teachers completed questionnaires to assess factors related to training and program implementation. More than one-fourth (27%) of master trainers conducted training sessions, and 60% of teachers taught the curriculum. While implementation fidelity was relatively high, teachers were less likely to use the more innovative elements of the program. Trainers and teachers who conducted training and/or taught the LST Program were more enthusiastic toward the program than those who did nothing beyond being trained.

In this investigation of the roles of 2 different dimensions of mood (pleasantness and arousal) in mood-dependent memory (MDM), participants generated words while listening to a selection of independently rated mood music (normative study and Experiment 5). Then they recalled the words while listening to another mood-music selection (Experiments 1-3) or to a verbal-mood scenario (Experiment 4). Changing only the dimension of mood pleasantness from generation to recall decreased memory whether the intended moods were explicitly defined or not. However, changing only arousal decreased memory only when moods were defined. Thus, pleasantness-dependent memory, but not arousal-dependent memory, occurred consistently. Although MDM also occurred with simultaneous changes in both dimensions, the effect was not significantly greater than that of pleasantness-dependent memory. The results are discussed in terms of 2-dimensional theories of emotion as applied to memory.

Many integrin adhesion receptors bind ligands containing the Arg-Gly-Asp (RGD) peptide motif. Most integrins exhibit considerable specificity for particular ligands and can distinguish among the many conformations of RGD. In this study we identify the domain of the integrin beta subunit involved in determining ligand binding specificity. Chimeras of beta3 and beta5, the most homologous integrin beta subunits, were expressed with alphav on the surface of human 293 cells. The ligand binding phenotype of each chimera was assessed using the ligands Fab-9 and fibrinogen, both of which have a binding preference for alphavbeta3. The results of the study show that when exons C and D of the beta3 subunit (residues 95-233) are substituted into beta5, the chimera gained the ability to bind Fab-9 with an affinity close to that of wild-type alphavbeta3. This chimera was able to mediate cell adhesion to fibrinogen. Furthermore, the swap of only a 39-residue segment of this larger domain, beta3 residues 164-202, into the backbone of beta5 enabled the chimeric integrin to bind soluble Fab-9. This small domain is highly divergent among the integrin beta subunits, suggesting that it may play a role in determining ligand selection by all integrins.

A serologic, bacteriologic, and histopathologic examination for leptospires was carried out on 89 armadillos (Chaetophractus villosus) from Argentina. Forty-seven per cent of the serum samples yielded positive results when tested by microscopic-agglutination. Predominant agglutination reactions were to the Hebdomadis and Bataviae serogroups. A total of 15 Leptospira isolations (from 16.8 per cent of the animals tested) were obtained from kidney tisse. Nine of the isolates were identified as belonging to the Bataviae group serotypes argentiniensis, paidjan, or bataviae; three other isolates proved to be the Canicola group serotype canicola; two others were Leptospira biflexa strains; and the last isolate was found to be serotype hardjo of the Hebdomadis group. The latter finding represents the first isolation of serotype hardjo from this animal species. Histopathologic examination of kidneys from 11 of the animals yielding pathogenic leptospires permitted a diagnosis of interstitial nephritis. This intersitial nephritis, presenting the characteristic picture of lymphoid infiltration, appeared intense in two animals, moderate in five others, and only slight in the remaining four. These histopathologic findings of chronic nephritis, combined with the high positive serologic and cultural isolation rates, suggest that the armadillo is an important natural reservoir-host for pathogenic leptospirae.

The correlation between the modified counterimmunoelectrophoresis test and the indirect fluorescent-antibody test for detecting rabies virus antibodies in human sera was studied, using as a reference the standard mouse neutralization test. Higher sensitivity was observed with the counterimmunoelectrophoresis technique than with the indirect fluorescent-antibody method. The counterimmunoelectrophoresis test provides a practical quantitative alternative to the indirect fluorescent-antibody method.

A modified counterimmunoelectrophoresis (CIE/SN) technique was developed as a diagnostic procedure for the detection of serum-neutralizing antibodies to rabies virus. CIE/SN test results with sera from individuals undergoing postexposure rabies immunization compared favorably with those obtained by the standard mouse neutralization test procedure. Fractionation of selected sera by Sephadex G-200 column chromatography demonstrated that serological activity involved in both procedures was present in the immunoglobulin G-containing fractions of the sera. The mean advantage of the CIE/SN over the standard mouse neutralization test consists in considerably reducing the time required for results, a factor which can be of clinical importance in evaluating antibody levels to rabies virus. In addition, the CIE/SN method is simple to perform and inexpensive.

Of 1,065 persons sampled during a house-to-house survey of an area of the Department of Curuzú Cuatiá, Province of Corrientes, Argentina, 21 were seropositive to Brucella canis antibodies by the gel-diffusion test, using a saline-extracted B. ovis surface R antigen. Two positive reactors were similarly identified during a survey of rural schools in the Province of Neuquén, which included 887 persons. The findings are discussed in terms of current knowledge of this recently recognized zoonotic infection.

The search of leptospires was conducted in kidneys of 1,415 stray dogs in the city of São Paulo--Brazil. From them 35 isolations were got, serovar canicola was the most frequent (32 samples) followed by copenhageni (2 samples) and pomona (1 sample). For the first time serovar pomona was isolated from dog in Latin America. Also, monthly and seasonal variations are discussed in relation to the prevalence of leptospirosis.

Microscopic agglutination tests performed during 1971 and 1972 on Barbadian livestock showed positive serological reactions for leptospirosis as follows: cattle 51%, pigs 13%, sheep 18%, horses 64% and goats 19%. The serogroup Autumnalis predominated in all but horses in which the reactions to the Pyrogenes group appeared slightly higher. After the isolation of a strain of Leptospira serotype fort-bragg (Barbadian strain No. 119) of the Autumnalis serogroup in 1973, and its subsequent inclusion in our test battery of leptospiral antigens, high percentages of cattle, dogs, mongooses and man showed sero-positive reactions against the strain. Attention is called to the wide dissemination of the fort-bragg serotype on the island and to the role of rodents and the mongoose in its spread. 74 clinically affected Barbadian cattle from three herds were studied during 1975-76; 60 (81%) were serologically positive and nine different serogroups were represented. Predominant sero-positive reactions to Hebdomadis, Autumnalis, Ballum and Pyrogenes antigens were recorded. The highest titres were against Autumnalis, Hebdomadis and Pomona. Hebdomadis and Pomona serogroup antibodies may be due to many importations of cattle with those infections into Barbados.

The counterimmunoelectrophoresis (CIE) technique employing a soluble extract antigen was found useful in screening human sera for antileptospiral antibodies to multiple leptospiral serovars. The CIE test results with sera from patients with suspected cases of leptospirosis and sera from a control group compared favorably (97.9%) with those obtained by the microscopic agglutination test using a battery of live leptospiral antigens. CIE is easy to perform, is highly sensitive, uses an antigen which is very stable at room temperature, and permits the screening of many sera in a short period of time. The CIE technique appears to be ideally suited to a small laboratory where facilities may be too limited for examining sera by the microscopic agglutination test.

This study demonstrates that the counterimmunoelectrophoresis test is a rapid and reliable method for the determination of antibody titres in hyperimmune antirabies sera. The application of this method to the selection of human sera for the production of antirabies globulin and for the final standardization of serum batches is discussed.

The results of a retrospective study of human leptospirosis cases occurring in Barbados during the period 19-68-74, and of serological findings among high risk occupational groups, fever cases and health centre patients monitored for the disease during 1975-77, indicate that infection by serotype fort-bragg of the Autumnalis group is widespread in this Caribbean island. The occupational groups most affected are sanitation workers and sugar-cane workers. Results of serological tests conducted at the principle hospital are comparable with the results obtained by the microscopic agglutination reference test procedure conducted at the Pan American Zoonosis Centre (CEPANZO).

A serological evaluation was done on the prevalence of bovine leptospirosis in Argentina. In 1,857 serum samples obtained from the major cattle raising areas of the country, 59.1 percent showed leptospiral agglutinins in the microscopic-agglutination test. The most frequent leptospiral antigens showing antibody reactions were the hebdomadis group serotypes, of which 45.8 per cent of the sera reacted to Leptospira hardjo with titres ranging from 1:100 to 1:25,600. Six Leptospira isolations were made from 161 bovine kidneys collected at local abattoirs. Their isolation and subsequent identification as serotype L. hardjo is described. This study reports on L. hardjo in cattle of Argentina for the first time and confirms the need for improved cultural methodology for its isolation.

The in vitro effectiveness of furazolidone combined with neomycin for the control of contaminants in Leptospira cultures was investigated. Enhanced additive or synergistic bactericidal activity was apparent with the combination when it was compared with each agent used separately or when compared with 5-fluorouracil. Combined furazolidone and neomycin, at 5-mug/ml concentrations each in Fletcher medium or in implanted sensitivity disks of 50 mug and 10 mug, respectively, was effective in inhibiting contaminants and did not interfere with the growth of leptospira belonging to 66 leptospiral collection serotypes. A simple technique for decontaminating swine kidneys from an abattoir for cultural isolation of leptospiras is described. The method involves exposing renal tissue diluted in saline containing furazolidone and neomycin in combination (each in a concentration of 25 mug/ml) for 1 h prior to inoculating culture media. The method is suitable for routine use in the isolation of leptospiras from contaminated clinical or pathological specimens.