Yeast 26S proteasome nuclear import is coupled to nucleus-specific degradation of the karyopherin adaptor protein Sts1.

In eukaryotes, the ubiquitin-proteasome system is an essential pathway for protein degradation and cellular homeostasis. 26S proteasomes concentrate in the nucleus of budding yeast Saccharomyces cerevisiae due to the essential import adaptor protein Sts1 and the karyopherin-α protein Srp1. Here, we show that Sts1 facilitates proteasome nuclear import by recruiting proteasomes to the karyopherin-α/ß heterodimer. Following nuclear transport, the karyopherin proteins are likely separated from Sts1 through interaction with RanGTP in the nucleus. RanGTP-induced release of Sts1 from the karyopherin proteins initiates Sts1 proteasomal degradation in vitro. Sts1 undergoes karyopherin-mediated nuclear import in the absence of proteasome interaction, but Sts1 degradation in vivo is only observed when proteasomes successfully localize to the nucleus. Sts1 appears to function as a proteasome import factor during exponential growth only, as it is not found in proteasome storage granules (PSGs) during prolonged glucose starvation, nor does it appear to contribute to the rapid nuclear reimport of proteasomes following glucose refeeding and PSG dissipation. We propose that Sts1 acts as a single-turnover proteasome nuclear import factor by recruiting karyopherins for transport and undergoing subsequent RanGTP-initiated ubiquitin-independent proteasomal degradation in the nucleus.

Differences in Minority Stress Experiences, Mental Health, and Relationship Quality Outcomes Among Bisexual, Pansexual, and Queer Women.

The majority of sexual minority women in the United States today identify as bi+. Recent research suggests that "non-traditional" bi+ labels such as pansexual and queer are being adopted more frequently than ever before, making it increasingly important to evaluate whether these women have unique needs. In the current study, we explored differences in minority stress experiences, mental health, and relationship quality outcomes by sexual identity label among women who identify with the most common bi+ labels: bisexual, pansexual, and queer. Participants were 285 bi+ cisgender women in romantic relationships. They completed online measures of minority stress (antibisexual experiences, identity concealment, disconnection from the sexual and gender minority (SGM) community, and internalized stigma), mental health (depression and anxiety), and relationship quality (satisfaction and commitment). Overall, participants reported similar experiences of minority stress and few differences in their mental health outcomes. However, there were differences in antibisexual experiences by sexual identity label, such that pansexual women reported more frequent antibisexual experiences than bisexual and queer women. There were also differences in relationship quality by sexual identity label, such that bisexual women reported higher satisfaction than pansexual women and higher commitment than both pansexual and queer women. Findings suggest that pansexual and queer women may be facing their own unique challenges, even compared to bisexual women. Clinical prevention and intervention efforts can be tailored for these women to include strategies to cope with more frequent exposure to antibisexual experiences, as well as relationship education and skill-building to promote healthy romantic relationships.

Synergistically Stabilizing Zinc Anodes by Molybdenum Dioxide Coating and Tween 80 Electrolyte Additive for High-Performance Aqueous Zinc-Ion Batteries.

Recently, aqueous zinc-ion batteries (ZIBs) have become increasingly attractive as grid-scale energy storage solutions due to their safety, low cost, and environmental friendliness. However, severe dendrite growth, self-corrosion, hydrogen evolution, and irreversible side reactions occurring at Zn anodes often cause poor cyclability of ZIBs. This work develops a synergistic strategy to stabilize the Zn anode by introducing a molybdenum dioxide coating layer on Zn (MoO2@Zn) and Tween 80 as an electrolyte additive. Due to the redox capability and high electrical conductivity of MoO2, the coating layer can not only homogenize the surface electric field but also accommodate the Zn2+ concentration field in the vicinity of the Zn anode, thereby regulating Zn2+ ion distribution and inhibiting side reactions. MoO2 coating can also significantly enhance surface hydrophilicity to improve the wetting of electrolyte on the Zn electrode. Meanwhile, Tween 80, a surfactant additive, acts as a corrosion inhibitor, preventing Zn corrosion and regulating Zn2+ ion migration. Their combination can synergistically work to reduce the desolvation energy of hydrated Zn ions and stabilize the Zn anodes. Therefore, the symmetric cells of MoO2@Zn∥MoO2@Zn with optimal 1 mM Tween 80 additive in 1 M ZnSO4 achieve exceptional cyclability over 6000 h at 1 mA cm-2 and stability (>700 h) even at a high current density (5 mA cm-2). When coupling with the VO2 cathode, the full cell of MoO2@Zn∥VO2 shows a higher capacity retention (82.4%) compared to Zn∥VO2 (57.3%) after 1000 cycles at 5 A g-1. This study suggests a synergistic strategy of combining surface modification and electrolyte engineering to design high-performance ZIBs.

Sis2 regulates yeast replicative lifespan in a dose-dependent manner.

Application of microfluidic platforms facilitated high-precision measurements of yeast replicative lifespan (RLS); however, comparative quantification of lifespan across strain libraries has been missing. Here we microfluidically measure the RLS of 307 yeast strains, each deleted for a single gene. Despite previous reports of extended lifespan in these strains, we found that 56% of them did not actually live longer than the wild-type; while the remaining 44% showed extended lifespans, the degree of extension was often different from what was previously reported. Deletion of SIS2 gene led to the largest RLS increase observed. Sis2 regulated yeast lifespan in a dose-dependent manner, implying a role for the coenzyme A biosynthesis pathway in lifespan regulation. Introduction of the human PPCDC gene in the sis2Δ background neutralized the lifespan extension. RNA-seq experiments revealed transcriptional increases in cell-cycle machinery components in sis2Δ background. High-precision lifespan measurement will be essential to elucidate the gene network governing lifespan.

Relationship between live body condition score and carcass fat measures in equine.

Relationships between live body condition score (BCS) and carcass fat depots have not been well established in equine. Our study was designed to quantify the relationship between BCS and fat depot measurements from equine carcasses. Live horses (n = 429) were evaluated immediately prior to immobilization at a commercial equine processor. Horses were independently assigned a BCS by a panel of three trained evaluators; BCS was evaluated by visual appraisal and manual palpation of the neck, withers, back, ribs, behind the shoulder, and tailhead. Median BCS frequencies were: 3.0 (n = 9), 4.0 (n = 43), 5.0 (n = 116), 6.0 (n = 86), 7.0 (n = 72), 8.0 (n = 76), and 9.0 (n = 27). Sex (stallion [n = 5], mare [n = 159], or gelding [n = 114]) and breed type (draft [n = 56], stock [n = 363], pony [n = 8], or mule [n =3]) were also denoted. Horses were processed for human consumption according to industry-accepted procedures under the supervision of the Canadian Food Inspection Agency. During the harvest process, all kidney-pelvic-heart (KPH) fat was trimmed from the carcass and weighed. After chilling, the marbling score was subjectively evaluated using beef grading standards. Carcass fat trim was weighed during the fabrication process. As BCS increased, hot carcass weight (HCW), absolute KPH weight, KPH expressed as a percentage of HCW, marbling score, neck fat depth, absolute weight of trimmed carcass fat, and trimmed carcass fat as a percentage of HCW increased (P < 0.01). A strong correlation (r = 0.74; P < 0.01) was detected between BCS and absolute KPH weight. Similarly, correlations between BCS and percentage of KPH (r = 0.65), neck fat depth (r = 0.60), absolute trimmed carcass fat (r = 0.58), trimmed carcass fat as a percentage of HCW (r = 0.54), marbling score (r = 0.54), and HCW (r = 0.52) were also detected (P < 0.01). These data indicate a strong relationship between subjective live BCS and objectively measured carcass fat depots in various equine breed types and sexes.

Action potential shortening rescues atrial calcium alternans.

KEY POINTS: Cardiac alternans refers to a beat-to-beat alternation in contraction, action potential (AP) morphology and Ca2+ transient (CaT) amplitude, and represents a risk factor for cardiac arrhythmia, including atrial fibrillation. We developed strategies to pharmacologically manipulate the AP waveform with the goal to reduce or eliminate the occurrence of CaT and contraction alternans in atrial tissue. With combined patch-clamp and intracellular Ca2+ measurements we investigated the effect of specific ion channel inhibitors and activators on alternans. In single rabbit atrial myocytes, suppression of Ca2+ -activated Cl- channels eliminated AP duration alternans, but prolonged the AP and failed to eliminate CaT alternans. In contrast, activation of K+ currents (IKs and IKr ) shortened the AP and eliminated both AP duration and CaT alternans. As demonstrated also at the whole heart level, activation of K+ conductances represents a promising strategy to suppress alternans, and thus reducing a risk factor for atrial fibrillation. ABSTRACT: At the cellular level alternans is observed as beat-to-beat alternations in contraction, action potential (AP) morphology and magnitude of the Ca2+ transient (CaT). Alternans is a well-established risk factor for cardiac arrhythmia, including atrial fibrillation. This study investigates whether pharmacological manipulation of AP morphology is a viable strategy to reduce the risk of arrhythmogenic CaT alternans. Pacing-induced AP and CaT alternans were studied in rabbit atrial myocytes using combined Ca2+ imaging and electrophysiological measurements. Increased AP duration (APD) and beat-to-beat alternations in AP morphology lowered the pacing frequency threshold and increased the degree of CaT alternans. Inhibition of Ca2+ -activated Cl- channels reduced beat-to-beat AP alternations, but prolonged APD and failed to suppress CaT alternans. In contrast, AP shortening induced by activators of two K+ channels (ML277 for Kv7.1 and NS1643 for Kv11.1) abolished both APD and CaT alternans in field-stimulated and current-clamped myocytes. K+ channel activators had no effect on the degree of Ca2+ alternans in AP voltage-clamped cells, confirming that suppression of Ca2+ alternans was caused by the changes in AP morphology. Finally, activation of Kv11.1 channel significantly attenuated or even abolished atrial T-wave alternans in isolated Langendorff perfused hearts. In summary, AP shortening suppressed or completely eliminated both CaT and APD alternans in single atrial myocytes and atrial T-wave alternans at the whole heart level. Therefore, we suggest that AP shortening is a potential intervention to avert development of alternans with important ramifications for arrhythmia prevention and therapy.

Maintenance of S. aureus in Co-culture With P. aeruginosa While Growing as Biofilms.

Bacterial biofilms are found in various environmental niches and are mostly comprised by two or more bacterial species. One such example, are the mixed species bacterial biofilms found in chronic lung infections of cystic fibrosis (CF) patients, which include the Staphylococcus aureus and Pseudomonas aeruginosa bacterial species. S. aureus is one of the CF lung initial colonizers and is assumed to be abrogated when P. aeruginosa becomes established, eliminating its involvement as the infection evolves. Common models used in research do not mimic the actual progression of the mixed species biofilms thus, in this work we developed an in vitro model, where S. aureus biofilms establish prior to the introduction of P. aeruginosa, simulating a state that is phenotypically more similar to the one found in CF lungs. Overall our results demonstrate that S. aureus is not outcompeted, and that timing of inoculation and bacterial concentration affect the final bacterial ratio and quorum sensing related gene expression during the dual species biofilm development.

Sex and regional differences in rabbit right ventricular L-type calcium current levels and mathematical modelling of arrhythmia vulnerability.

NEW FINDINGS: What is the central question of this study? Regional variations of ventricular L-type calcium current (ICa-L ) amplitude may underlie the increased arrhythmia risk in adult females. Current amplitude variations have been described for the left ventricle but not for the right ventricle. What is the main finding and its importance? Adult female rabbit right ventricular base myocytes exhibit elevated ICa-L compared with female apex or male myocytes. Oestrogen upregulated ICa-L in cultured female myocytes. Mathematical simulations modelling long QT syndrome type 2 demonstrated that elevated ICa-L prolonged action potentials and induced early after-depolarizations. Thus, ventricular arrhythmias in adult females may be associated with an oestrogen-induced upregulation of ICa-L . Previous studies have shown that adult rabbit left ventricular myocytes exhibit sex and regional differences in L-type calcium current (ICa-L ) levels that contribute to increased female susceptibility to arrhythmogenic early after-depolarizations (EADs). We used patch-clamp recordings from isolated adult male and female rabbit right ventricular myocytes to determine apex-base differences in ICa-L density and used mathematical modelling to examine the contribution of ICa-L to EAD formation. Current density measured at 0 mV in female base myocytes was 67% higher than in male base myocytes and 55% higher than in female apex myocytes. No differences were observed between male and female apex myocytes, between male apex and base myocytes, or in the voltage dependences of ICa-L activation or inactivation. The role of oestrogen was investigated using cultured adult female right ventricular base myocytes. After 2 days, 17ß-estradiol (1 nm) produced a 65% increase in ICa-L density compared with untreated control myocytes, suggesting an oestrogen-induced upregulation of ICa-L . Action potential simulations using a modified Luo-Rudy cardiomyocyte model showed that increased ICa-L density, at the level observed in female base myocytes, resulted in longer duration action potentials, and when combined with a 50% reduction of the rapidly inactivating delayed rectifier potassium current conductance to model long QT syndrome type 2, the action potential was accompanied by one or more EADs. Thus, we found higher levels of ICa-L in adult female right ventricle base myocytes and the upregulation of this current by oestrogen. Simulations of long QT syndrome type 2 showed that elevated ICa-L contributed to genesis of EADs.

Normal vs cancer thyroid stem cells: the road to transformation.

Recent investigations in thyroid carcinogenesis have led to the isolation and characterisation of a subpopulation of stem-like cells, responsible for tumour initiation, progression and metastasis. Nevertheless, the cellular origin of thyroid cancer stem cells (SCs) remains unknown and it is still necessary to define the process and the target population that sustain malignant transformation of tissue-resident SCs or the reprogramming of a more differentiated cell. Here, we will critically discuss new insights into thyroid SCs as a potential source of cancer formation in light of the available information on the oncogenic role of genetic modifications that occur during thyroid cancer development. Understanding the fine mechanisms that regulate tumour transformation may provide new ground for clinical intervention in terms of prevention, diagnosis and therapy.

Papillary thyroid carcinoma (PTC) in Lynch syndrome: Report of two cases and discussion on Lynch syndrome behaviour and genetics.

We present here two cases of papillary thyroid carcinoma (PTC) in patients affected by Lynch syndrome (LS). The first case is a 47-year-old woman with typical hereditary non-polyposis colorectal cancer (HNPCC) syndrome, reported with endometrial and ovarian carcinoma at age 43, and colon cancer at age 45. The patient underwent total thyroidectomy and central node dissection in 2007, at 47years old, with a histological diagnosis of PTC (T1aN1a). Molecular genetics showed a germ-line mutation of the MLH1 gene, 1858 G>T(E620X), with substitution of glycine with a stop codon at position 620. This mutation has pathogenetic significance and was considered responsible for the various tumours of the HNPCC spectrum. In particular, in the same kindred, spanning 5 generations, there were 5 members with colorectal cancer, 4 with endometrial cancer, 3 with gastric and 2 with breast cancer. The second case is a 34-year-old man with typical HNPCC syndrome with colonic resection for colon cancer at age 21. The patient underwent total thyroidectomy with central and lateral node dissection in 2010, at age 34, with a histological diagnosis of PTC with nodal metastases (pT4N1b). Molecular genetic analysis showed a germ-line mutation of the MSH2 gene (thymine insertion at position 907). This mutation had pathogenetic significance and was considered responsible for HNPCC development. Two similar cases have been reported: a 39-year-old woman, and a 44-year-old woman, affected by HNPCC syndrome, with anaplastic thyroid carcinoma and undifferentiated thyroid carcinoma, respectively. We reviewed the Lynch syndrome literature on the history, genetics and expanding tumour spectrum of this condition.

Stuffed Animals in the Operating Room: A Reservoir of Bacteria With a Simple Solution.

BACKGROUND: Despite hand washing and other protocols surgical-site infections (SSIs) have not been eliminated. This implies that either current measures are not effective or there are alternative sources of bacterial exposure to the surgical wound. In this study we tested the hypothesis that stuffed animals or other items allowed to accompany pediatric patients to the operating room as a way to ease anxiety may represent a reservoir of bacteria. METHODS: Stuffed animals brought into the operating room and stuffed animals that were washed and dried in a conventional washer/dryer and placed in clean sealable plastic bags were swabbed and bacterial colonies were quantified. Results were reported as no growth, light growth, moderate growth, and heavy growth. RESULTS: All stuffed animals showed bacterial growth. A total of 79% of stuffed animals were effectively "sterilized" by a single wash and dry cycle in a conventional home washer/dryer. Sterilized stuffed animals remained sterile after being packed in a sealed bag for 24 hours. CONCLUSIONS: These results indicate that items of comfort, such as stuffed animals, brought into the operating room with a benevolent purpose may represent a reservoir of bacteria that could lead to unwanted SSI. Washing an item of comfort 1 day before surgery effectively sterilizes that item of comfort. Future studies will be needed to determine a correlation between "culture positive" stuffed animals and SSI or if providing a child with a "sterile" stuffed animal reduces SSI.

The role of BRAF(V600E) mutation as poor prognostic factor for the outcome of patients with intrathyroid papillary thyroid carcinoma.

BACKGROUND: BRAF(V600E) mutation, which represents the most frequent genetic mutation in papillary thyroid carcinoma (PTC), is widely considered to have an adverse outcome on PTC outcome, however its real predictive value is not still well stated. The aim of the present study was to evaluate if BRAF(V600E) mutation could be useful to identify within patients with intrathyroid ultrasound-N0 PTC those who require more aggressive treatment, by central neck node dissection (CLND) or subsequent postoperative (131)I treatment. METHODS: Among the whole series of 931 consecutive PTC patients operated on at 2nd Clinical Surgery of University of Padova and at General Surgery Department of University of Trieste during a period from January 2007 to December 2012, we selected 226 patients with an intrathyroid tumor and no metastases (preoperative staging T1-T2, N0, M0). BRAF(V600E) mutation was evaluated by PCR-single-strand conformation polymorphism analysis and direct genomic sequencing. We analyzed the correlation between the presence/absence of the BRAF(V600E) mutation in the fine-needle aspiration (FNA) and the clinical-pathological features: age, gender, extension of surgery, node dissection, rate of cervical lymph node involvement, tumor size, TNM stage, variant of histotype, mono/plurifocality, association with lymphocitary chronic thyroiditis, radioactive iodine ablation doses, and outcome. RESULTS: The BRAF(V600E) mutation was present in 104 of 226 PTC patients (47.8%). BRAF(V600E) mutation correlated with multifocality, more aggressive variants, infiltration of the tumoral capsule, and greater tumor's diameter. BRAF(V600E) mutation was the only poor prognostic factor in these patients. DISCUSSION: In our series, BRAF(V600E) mutation demonstrated to be an adverse prognostic factor indicating aggressiveness of disease and it could be useful in the management of low-risk PTC patients, as supplementary prognostic factor to assess the preoperative risk stratification with the aim to avoid unnecessary central neck node dissection (BRAF pos.) or to perform complementary (131)I-therapy (BFAF neg.).

Building without a plan: the career experiences of Australian strength and conditioning coaches.

The purpose of this investigation was to explore the career experiences of Australian strength and conditioning coaches. Six Australian strength and conditioning coaches (mean age = 33.7 years, SD = 6.0 years) with a mean of 10.4 (SD = 4.9) years experience working with elite Olympic and professional athletes were interviewed about their experiences of career development. Each interview was transcribed verbatim and analyzed to produce key themes and subthemes relating to (a) work environments, (b) sport management practice, (c) career development processes, and (d) career building strategies. The work environments of Australian strength and conditioning coaches were found to be poor because of long working hours and irregular human resource policy and management practices of sport organizations. Because of the volatile and unpredictable nature of their working conditions, the coaches interviewed have only a short-term view of their career creating considerable stress in their lives. The coaches interviewed found it difficult to develop their careers because their only options were self-supported and self-funded professional development activities. The coaches in this study believed that more needed to be done at a policy and management level by sport organizations and their professional body to enhance the career development of strength and conditioning coaches because they play a key role in both athlete and sport organization performance. These results may help sport organizations develop policies and management practices that enhance the careers of strength and conditioning coaches and will have important practical implications for the education and development of sport professionals.

Can we trust ex vivo mechanical testing of fresh--frozen cadaveric specimens? The effect of postfreezing delays.

BACKGROUND: Because embalming has been demonstrated to decrease the mechanical integrity of bone, most investigators favor fresh-frozen specimens for biomechanical evaluation. However, little is known about how the integrity of fresh--frozen specimens may change during biomechanical testing or may be affected by standard practices in testing. OBJECTIVE: The purpose of this study was to evaluate how the time after removal from a freezer may affect the mechanical properties of fresh--frozen diaphyseal bone. METHODS: Matched pairs of nonosteoporotic fresh--frozen human cadaveric femora were thawed before instrumentation with bicortical screws. Matched femora were reserved for either control or delayed use. Each specimen received standard diaphyseal bicortical screws (six or more in each group). At specified time points, screws were axially pulled out following the guidelines of ASTM F543-07. Test groups were stored in air (21 ± 0.5°C) for 16, 50, or 90 hours. In the control group, screws were pulled out at 16 hours, which corresponds to the minimum elapsed time for specimen thawing, instrumentation, potting, and biomechanical test initiation. This represents the baseline mechanical properties of the fresh--frozen bone at the inception of any biomechanical test. The 90-hour group corresponds to the time needed to cycle a construct 300,000 times at a physiological test frequency of 1 Hz. This corresponds approximately to 2 to 4 months of in vivo loading. A midpoint of 50 hours was also tested, representing approximately 180,000 cycles. RESULTS: Failure for all specimens occurred as a result of bone failure at the screw-to-bone interface. There was a decrease in screw pullout strength as exposure time in air increased. The 50-hour test group showed a 9% decrease in screw pullout strength as compared with the 16-hour control group (P = 0.81). However, the 90-hour test group showed a 30% decrease in screw pullout strength as compared with the 16-hour control group (P = 0.04). CONCLUSION: This study indicates that when using fresh-frozen cadaveric bone in biomechanical tests to simulate the orthopaedic clinical setting, specimen exposure time should be considered. The timing of testing should be kept constant between specimens to allow for a proper comparison. Furthermore, for fresh--frozen cadavers, the physical properties of bone may be detrimentally affected in biomechanical testing that exceeds the 50-hour time point after removal from the freezer.

Opinion survey regarding pediatric orthopaedic trauma call and emergency trauma management.

BACKGROUND: To determine the attitudes and practices of pediatric orthopaedic surgeons regarding on-call coverage and emergency fracture management. METHODS: A 32-question online survey was sent to all 597 active members of the Pediatric Orthopaedic Society of North America. There were 296 completed surveys, for a response rate of 49.6%. RESULTS: Of the respondents, 85.1% were male. The respondents ranged in age from 30 to older than 70 years, with 54% between 36 and 50 years of age, corresponding to an average of 15 years in practice. Seventy-seven percent of the respondents felt that taking trauma call is an integral aspect of being a pediatric orthopaedist. Of the respondents, 64.9% take call 1 to 9 times per month, 15.8% take 10 to 19 calls, 2.7% take 20 or more, and 16.6% take no call. The number of orthopaedists taking call per practice was fairly evenly distributed between 3 and 10. Call was shared equally in 32% of practices, and mandatory in 72%. Twenty-eight percent of the respondents were additionally compensated for taking calls, in amounts ranging from $100 to $2000 per night, with 1000 dollars the most common rate. One third of operative cases are done that night; one third, the next day; and one third, later in the week. Twenty-four percent of the respondents have dedicated operative block time on the day after the call. Forty-seven percent have a dedicated fracture clinic, of which 51% receive institutional support. CONCLUSIONS: Providing emergency trauma care for children is an integral aspect of pediatric orthopaedics. This survey provides information on the attitudes and strategies of practicing pediatric orthopaedic surgeons in the face of decreasing manpower and increasing demand for such services.

Tibial insertion of the posterior cruciate ligament: a sagittal plane analysis using gross, histologic, and radiographic methods.

PURPOSE: The literature is imprecise regarding the ideal tibial site for the posterior cruciate ligament (PCL) placement. We detail anatomic and radiographic landmarks for consistent placement of graft fixation in PCL reconstruction. METHODS: Fourteen fresh-frozen cadaver knees were sectioned in the sagittal plane. The distance from the posterior cortex of the tibia to the anterior edge of the PCL was measured. Three specimens were fixed in 10% formalin and stained using hematoxylin-eosin and trichrome to determine ligament fiber distribution and insertion. Two knees were used for radiographic analysis of pin placement. RESULTS: The mean distance across the PCL facet from the posterior cortex to the anterior edge of the PCL was 15.6 mm (+/-1.1 mm). Histologic analysis in three knees showed that the PCL fibers inserting along the PCL facet comprise the bulk of the ligament, while the fibers that insert along the posterior cortex are less than 0.5 mm thick. CONCLUSIONS: The bulk of the PCL inserts in the posterior half of the PCL facet. We show that, in the sagittal plane, the center of the working fibers of the PCL lies 7 mm anterior to the posterior cortex of the tibia, measured along the PCL facet. Tunnel placement at the center of the original ligament can be measured along the PCL facet as seen in a true lateral radiographic view. CLINICAL RELEVANCE: This study provides anatomic and radiographic criteria helpful for guide-pin placement in arthroscopic PCL reconstruction.

Immediate weight-bearing after treatment of a comminuted fracture of the femoral shaft with a statically locked intramedullary nail.

BACKGROUND: The purpose of this two-part investigation was to test the feasibility, safety, and efficacy of immediate weight-bearing after treatment of fractures of the shaft of the femur with a statically locked intramedullary nail. METHODS: In the first part of the investigation, a biomechanical study was performed to determine the fatigue strength of eleven different statically locked intramedullary nail constructs. Segmentally comminuted midisthmal fractures were simulated with use of sections of polyvinyl chloride pipe; each construct was cyclically loaded in compression with use of physiologically relevant loads in a materials testing machine at eight hertz. The fatigue tests were conducted according to the so-called staircase method, and the construct was considered to have run out (exceeded its anticipated service life) if it had not failed after 500,000 cycles. In the second part of the study, a clinical investigation of immediate weight-bearing after treatment of comminuted fractures of the femoral shaft with a Russell-Taylor (RT-2) construct was performed. Complete follow-up data were available for twenty-eight of the thirty-five patients (thirty-six fractures) entered into the study. RESULTS: In Part I of the study, two constructs, a statically locked twelve-millimeter-diameter Russell-Taylor femoral nail with two distal locking screws (RT-2) and a statically locked twelve-millimeter-diameter Zimmer femoral nail with two distal locking screws (Z-2), had significantly higher mean fatigue strengths (2171 and 2113 newtons, respectively) than all other constructs tested (p<0.001), but the strengths of these two constructs were not significantly different from each other. Constructs with only one distal locking screw demonstrated significantly lower (p<0.05) fatigue strengths than the two-screw constructs. These results suggest that full weight-bearing during the weeks immediately after insertion of the nail may be possible, even for patients who have a comminuted fracture of the femoral shaft. In Part II of the study, twenty-six of the twenty-eight patients were bearing full weight on the fractured limb or limbs at the six-week follow-up visit. All fractures united; only one of these needed an additional procedure (the removal of the screws five months after the insertion of the nail) to stimulate union. No loss of fixation, such as back-out or breakage of a locking screw or breakage or bending of the intramedullary nail, occurred. CONCLUSIONS: We concluded from this two-part investigation that immediate weight-bearing after stabilization of a comminuted fracture of the femoral shaft with a statically locked intramedullary nail is safe when the construct has a relatively high fatigue strength. Immediate weight-bearing after stabilization of a fracture of the femoral shaft permits patients who have multiple fractures of the extremity to walk and to participate in physical therapy earlier, possibly decreasing the duration of the hospital stay or reducing the need for prolonged rehabilitation on an inpatient basis.

Out-of-hospital intravenous access: unnecessary procedures and excessive cost.

OBJECTIVE: To evaluate the concordance with criteria developed by the study investigators and supply costs associated with placement of i.v. lines and saline locks by paramedics in the out-of-hospital setting. METHODS: This was a retrospective consecutive case series at an urban base hospital. Patients were treated by paramedics using one base hospital for medical control during December 1995. Base hospital written records and taped patient calls were reviewed to determine actual i.v. access method used by paramedics, chief complaint, and whether fluid administration was ordered. Indicated method of i.v. access was determined for each patient based on predetermined criteria developed by the investigators. i.v. access methods were ranked by cost of supplies as follows: i.v. line (i.v.) > saline lock (SL) > no i.v. line (No i.v.). An assignment of concordant treatment was made when actual = indicated method, discordant-overtreatment when actual > indicated, and discordant-undertreatment when actual < indicated. RESULTS: 452 patients were treated via radio by the base hospital during the study period. 380 of 452 (84%) received an i.v.. 28 of 380 (7%) received fluid resuscitation in the field. 166 of 452 (37%) received concordant treatment; 253 (56%) discordant-overtreatment; and 33 (7%) discordant-undertreatment. Pediatric patients (< or =14 years of age) were more likely to be undertreated as compared with adults, 33% vs 3% (p < 0.001). Patients who had medical chief complaints were more likely to receive discordant-overtreatment as compared with patients who had trauma chief complaints, 61% vs 32% (p < 0.001). 73% of chest pain patients received discordant-overtreatment. Based on these data, the yearly cost of supplies used in i.v. access discordant-overtreatment was $13,735 for this base hospital and $560,000 for the Los Angeles County emergency medical services (EMS) system. 91% of the excess supply cost is due to patients' receiving an i.v. instead of a SL. CONCLUSION: Based on study criteria for utilization of i.v. lines vs SLs in the field, paramedics and base hospital personnel often provide discordant-overtreatment of patients by placement of an i.v. when a SL or No i.v. would suffice, resulting in unnecessary costs for EMS systems.

The management of patients in a phobia clinic.

Management of people in this phobia clinic is based on a theory that phobias result from misinterpretations of the effects of a natural process that generates fear in responses to imagined dangers as in a nightmare. With support, guidance, exposure, and information, phobic people learn in individual and group settings to confront, control, and understand their phobic experience.