Finding the Optimal Screening Test for Periprosthetic Joint Infection: A Prospective Study

BACKGROUND

No single test has demonstrated absolute accuracy in the diagnosis of periprosthetic joint infection (PJI). Serological markers are often used as screening tools to avoid unnecessary joint aspiration in cases with a low probability of infection. This study aimed to determine the utility of standard-of-care serological tests as a screening tool for PJI in patients undergoing revision arthroplasty.

METHODS

This prospective study enrolled 502 patients undergoing revision hip or knee arthroplasty between May 2017 and August 2021. A PJI was defined using a modified definition of the 2018 International Consensus Meeting criteria. Plasma D-dimer, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and fibrinogen were measured preoperatively. There were 82 patients undergoing reimplantation who were excluded. Additionally, 8 patients who had an inconclusive International Consensus Meeting score were also excluded. Of the 412 included patients, 317 (76.9%) underwent revision for aseptic failure, and 95 (23.1%) had PJI. Receiver operating characteristic curves were used to assess the diagnostic utility of each serological test. A pairwise comparison with Bonferroni correction was performed to determine whether the differences in areas under the curve (AUCs) between the tests were significant. Additional analyses were performed to find the threshold for each test that offered 100% sensitivity, allowing it to be the optimal screening test.

RESULTS

All 4 serological markers, D-dimer (AUC 0.860, sensitivity 81.3%, specificity 81.7%), CRP (AUC 0.862, sensitivity 90.4%, specificity 70.0%), ESR (AUC 0.833, sensitivity 73.9%, specificity 85.2%), and fibrinogen (AUC 0.798, sensitivity 74.7%, specificity 75.4%), demonstrated comparable accuracy for the diagnosis of PJI (all P > .05). When maximizing sensitivity to 100%, D-dimer demonstrated the highest specificity (AUC 0.860, specificity 40.2%), outperforming ESR (AUC 0.833, specificity 3.3%), fibrinogen (AUC 0.798, specificity 2.3%), and CRP (AUC 0.862, specificity 0%). A plasma D-dimer level of ≥ 244 ng/mL was identified as the optimal cutoff for use as a screening test.

CONCLUSIONS

Although plasma D-dimer demonstrated similar diagnostic accuracy as CRP, ESR, and fibrinogen, it outperformed all 3 aforementioned serological markers when used as a screening test for PJI.

LEVEL OF EVIDENCE

Level II.

Allograft or Synthetic Mesh Extensor Mechanism Reconstruction After TKA Carries a High Risk of Infection, Revision, and Extensor Lag

BACKGROUND

Extensor mechanism disruption is a devastating complication after TKA. Extensor mechanism reconstruction can be performed using an allograft or synthetic mesh. Recent studies have disagreed about the durability of these reconstructions. Evaluating a larger series of reconstructions that use current popular techniques and principles provides information to guide patient and surgeon expectations while bringing to light the potential fate of patients who experience an infection postoperatively.

QUESTIONS/PURPOSES

(1) What was the 5-year survival free of repeat revision surgery or persistent extensor lag of more than 30° after allograft or synthetic mesh reconstruction of extensor mechanism disruptions after TKA, and did this differ between techniques? (2) What was the 5-year survival free of infection after allograft or mesh reconstruction, and what proportion of those patients experienced a secondary severe complication (arthrodesis or amputation)?

METHODS

Between April 2008 and December 2020, 123 patients underwent extensor mechanism reconstruction after TKA at one center. Of those, 37% (45) were lost to follow-up before 2 years, had not been seen in the past 5 years, did not reach a study endpoint (repeat revision or extensor lag > 30°) before that time, or underwent primary repair and thus could not be analyzed, leaving 63% (78) for analysis here. During the study period, we considered extensor mechanism surgery when acute or chronic disruption of the patellar or quadriceps tendon was present or there was a fracture of the patella resulting in extensor lag. The decision to use either mesh or an allograft largely depended on surgeon experience and familiarity with either technique. We collected patient demographics, operative details (location of disruption and presence of a hinged prosthesis), subsequent periprosthetic joint infection (PJI), and postoperative SF-12 and Knee Injury and Osteoarthritis Outcome Score, Joint Replacement, scores. We used Kaplan-Meier survivorship analysis, with endpoints of extensor lag more than 30° or revision of the reconstruction and PJI. The mean follow-up duration was 5.3 ± 3.2 years.

RESULTS

Survivorship free from revision or recurrent extensor lag was 54% (95% CI 44% to 66%) at 5 years. There was no difference between those undergoing reconstruction with allografts and those with mesh in terms of survivorship free from those endpoints at that timepoint (52% [95% CI 40% to 68%] versus 57% [95 CI% 41 to 78%]; p = 0.99). Survivorship free from PJI was 81% (95% CI 73% to 90%) at 2 years. There was no difference between those with allografts and those with mesh in terms of survivorship free from PJI at that timepoint (79% [95% CI 69% to 92%] versus 83% [95% CI 71% to 98%]; p = 0.75). Of the 17 patients who experienced PJI, four ultimately underwent arthrodesis and three more underwent transfemoral amputation.

CONCLUSION

Allograft and synthetic mesh reconstructions commonly left patients with persistent limb dysfunction, while several patients had PJI and some underwent salvage procedures. Although improvements have been made with regard to treating extensor mechanism disruptions, patients and surgeons should be well aware of the potential adverse outcomes when determining management and use these findings to conduct risk-benefit analyses. There is a need for future studies to identify protocols that improve the durability of reconstructions and to determine whether interventions such as prolonged prophylactic antibiotic therapy have a role in minimizing the risk of PJI.

LEVEL OF EVIDENCE

Level III, therapeutic study.

High Incidence of Acute Kidney Injury Following Antibiotic-Loaded Spacer Insertion for Periprosthetic Joint Infection: An Updated Review of the Literature

BACKGROUND

The use of antibiotic-impregnated cement during 2-stage revision arthroplasty for periprosthetic joint infection poses a risk of renal complications following spacer insertion. This systematic review aimed to investigate the rate of acute kidney injury (AKI) following antibiotic-loaded spacer insertion and to identify risk factors associated with this complication.

METHODS

A systematic review was performed using PubMed, Cochrane Central, and Scopus databases. All clinical studies that documented renal complications following antibiotic-loaded spacer insertion for periprosthetic knee (total knee arthroplasty [TKA]) or hip (total hip arthroplasty [THA]) infection were included. Articles that combined THA and TKA outcomes were also included and labeled "THA + TKA." Descriptive statistics were analyzed when data were available.

RESULTS

There were 24 studies (9 THA, 7 TKA, 8 THA + TKA) included. The mean incidences of spacer-related AKI across THA, TKA, and THA + TKA cohorts were 4.2 (range, 0 to 10%), 14 (range, 0 to 19%), and 27% (range, 0 to 35%), respectively. The most common patient-related risk factors for AKI were underlying chronic kidney disease or high baseline creatinine, low preoperative hemoglobin, and blood transfusion requirement. Spacer-related risk factors included high antibiotic dosage (>3.6 g/cement batch) and antibiotic type. While most recovered without complication, select patients required hemodialysis for acute management (2 THA, 18 THA + TKA) and/or developed chronic kidney disease (8 TKA, 8 THA).

CONCLUSION

The rate of AKI following spacer insertion was high and likely under-reported in the literature. Surgeons should be cognizant of this devastating complication and should closely monitor at-risk patients for AKI following antibiotic-loaded spacer insertion.

Plasma D-Dimer Is a Promising Marker to Guide Timing of Reimplantation: A Prospective Cohort Study

BACKGROUND

Two-stage exchange arthroplasty remains the preferred surgical treatment for chronic periprosthetic joint infection. Currently, there is no single reliable marker to determine the optimal timing for reimplantation. The purpose of this prospective study was to assess the diagnostic utility of plasma D-dimer and other serological markers in predicting successful control of infection following reimplantation.

METHODS

This study enrolled 136 patients undergoing reimplantation arthroplasty between November 2016 and December 2020. Strict inclusion criteria were applied including the need for a two-week "antibiotic holiday" prior to reimplantation. A total of 114 patients were included in the final analysis. Plasma D-dimer, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and fibrinogen were measured preoperatively. Treatment success was defined using the Musculoskeletal Infection Society Outcome-Reporting Tool. Receiver operating characteristic curves were used to assess the prognostic accuracy of each biomarker in predicting failure following reimplantation at a minimum 1-year follow-up.

RESULTS

Treatment failure occurred in 33 patients (28.9%) at a mean follow-up of 3.2 years (range, 1.0 to 5.7). Median plasma D-dimer was significantly higher in the treatment failure group (1,604 versus 631 ng/mL, P < .001), whereas median CRP, ESR, and fibrinogen were not significantly different between the success and failure groups. Plasma D-dimer demonstrated the best diagnostic utility (area under the curve [AUC] 0.724, sensitivity 51.5%, specificity 92.6%), outperforming ESR (AUC 0.565, sensitivity 93.3%, specificity 22.5%), CRP (AUC 0.541, sensitivity 87.5%, specificity 26.3%), and fibrinogen (AUC 0.485, sensitivity 30.4%, specificity 80.0%). Plasma D-dimer level of ≥1,604 ng/mL was identified as the optimal cutoff that predicted failure following reimplantation.

CONCLUSION

Plasma D-dimer was superior to serum ESR, CRP, and fibrinogen in predicting failure after the second stage of a two-stage exchange arthroplasty for periprosthetic joint infection. Based on the findings of this prospective study, plasma D-dimer may be a promising marker in assessing the control of infection in patients undergoing reimplantation surgery.

LEVEL OF EVIDENCE

Level II.

The Dome Technique for Managing Massive Anterosuperior Medial Acetabular Bone Loss in Revision Total Hip Arthroplasty: Short-Term Outcomes

Purpose

The dome technique is a technique used in performance of revision total hip arthroplasty (THA) involving intraoperative joining of two porous metal acetabular augments to fill a massive anterosuperior medial acetabular bone defect. While excellent outcomes were achieved using this surgical technique in a series of three cases, short-term results have not been reported. We hypothesized that excellent short-term clinical and patient reported outcomes could be achieved with use of the dome technique.

Materials and Methods

A multicenter case series was conducted for evaluation of patients who underwent revision THA using the dome technique for management of Paprosky 3B anterosuperior medial acetabular bone loss from 2013-2019 with a minimum clinical follow-up period of two years. Twelve cases in 12 patients were identified. Baseline demographics, intraoperative variables, surgical outcomes, and patient reported outcomes were acquired.

Results

The implant survivorship was 91% with component failure requiring re-revision in only one patient at a mean follow-up period of 36.2 months (range, 24-72 months). Three patients (25.0%) experienced complications, including re-revision for component failure, inter-prosthetic dual-mobility dissociation, and periprosthetic joint infection. Of seven patients who completed the HOOS, JR (hip disability and osteoarthritis outcome score, joint replacement) survey, five patients showed improvement.

Conclusion

Excellent outcomes can be achieved using the dome technique for management of massive anterosuperior medial acetabular defects in revision THA with survivorship of 91% at a mean follow-up period of three years. Conduct of future studies will be required in order to evaluate mid- to long-term outcomes for this technique.

Hyponatremia Is an Overlooked Sign of Trouble Following Total Joint Arthroplasty

BACKGROUND

Hyponatremia is a common electrolyte abnormality in arthroplasty patients. This issue, underrecognized by surgeons, can impact the postoperative course of patients. There are, however, little data on the implications of sodium disturbances following total joint arthroplasty (TJA). The primary aims of this study were to (1) report the rate of hyponatremia following TJA, and (2) examine the impact of hyponatremia on the perioperative course of TJA patients.

METHODS

This was a retrospective analysis of 3,071 primary and revision TJAs performed between 2015 and 2017. Based on preoperative and postoperative sodium values (pre-post), patients were classified into 4 groups: normonatremic-normonatremic (Group 1), normonatremic-hyponatremic (Group 2), hyponatremic-normonatremic (Group 3), and hyponatremic-hyponatremic (Group 4). Primary end points were length of stay (LOS), postoperative discharge, in-hospital complications, and 90-day readmissions.

RESULTS

The distribution of cases was 84.6% Group 1, 9.4% Group 2, 2.1% Group 3, and 3.8% Group 4. Overall, 13.2% of patients had hyponatremia after TJA. Older age, hip arthroplasty, general anesthesia, higher Charlson Comorbidity Index, congestive heart failure, revision surgery, and history of stroke, liver disease, and chronic kidney disease were risk factors for postoperative hyponatremia. Patients with postoperative hyponatremia (Groups 2 and 4) had greater likelihoods of having a 90-day complication and non-home discharge and greater LOS.

CONCLUSIONS

Postoperative hyponatremia was a relatively common occurrence in patients undergoing TJA, and was associated with greater LOS, complications, and non-home discharge. Surgeons should identify patients at risk for developing sodium abnormalities in order to optimize these patients and avoid increased resource utilization.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Dual-Mobility Versus Large Femoral Heads in Revision Total Hip Arthroplasty: Interim Analysis of A Randomized Controlled Trial

INTRODUCTION

This multicenter randomized controlled trial evaluated if dual-mobility bearings (DM) lower the risk of dislocation compared to large femoral heads (≥36mm) for patients undergoing revision total hip arthroplasty (THA) via a posterior approach.

METHODS

A total of 146 Patients were randomized to a DM (n=76; 46 mm median effective head size, range 36 to 59 mm) or a large femoral head (n=70; twenty-five 36 mm heads [35.7%], forty-one 40 mm heads [58.6%], and four 44mm heads [5.7%]). There were 71 single-component revisions (48.6%), 39 both-component revisions (26.7%), 24 reimplantations of THA after 2-stage revision (16.4%), seven isolated head and liner exchanges (4.8%), four conversions of hemiarthroplasty (2.7%), and one revision of a hip resurfacing (0.7%). Power analysis determined that 161 patients were required in each group to lower the dislocation rate from 8.4 to 2.2% (power=0.8, alpha=0.05).

RESULTS

At a mean of 18.2 months (range, 1.4 to 48.2), there were three dislocations in the large femoral head group compared to two in the DM cohort (4.3 vs. 2.6%; P=0.67). One patient in the large head group and none in the DM group were successfully treated with closed reduction without subsequent revision.

CONCLUSION

Interim analysis of this randomized controlled trial found no difference in the risk of dislocation between DM and large femoral heads in revision THA, although the rate of dislocation was lower than anticipated and continued follow up is needed.

Human Knee Has A Distinct Microbiome: Implications for Periprosthetic Joint Infection

INTRODUCTION

Pathogens causing prosthetic joint infection are thought to gain access to the knee during surgery or from a remote site in the body. Recent studies have shown that there is a distinct microbiome in various sites of the body. This prospective study, and first of its kind, was set up to investigate the presence of possible microbiome in human knee and compare the profile in different knee conditions.

METHODS

This transversal study prospectively obtained synovial fluid from 65 knees (55 patients) with various conditions that included normal knee, osteoarthritis, aseptic revision, and those undergoing revision for periprosthetic joint infection (PJI). The contralateral knee of patients who had a PJI were also aspirated to compare the composition of the PJI knee with uninfected contralateral knee. A minimum of 3 milliliters (ml) of synovial fluid was collected per joint. Then, the samples were aliquoted for culture and next generation sequencing (NGS) analysis.

RESULTS

The highest number of species was found in native osteoarthritic knees (P≤0.035). Cutibacterium, Staphylococcus, and Paracoccus species were dominant in native non-osteoarthritic knees, and meanwhile a markedly high abundance of Proteobacteria was observed in the osteoarthritic joints. Moreover, the contralateral and aseptic revision knees showed a similar trend in bacterial composition (P=0.75). The NGS analysis of patients who had PJI diagnosis, confirmed the culture results.

DISCUSSION/CONCLUSION

Distinct knee microbiome profiles can be detected in patients who have osteoarthritis and other knee conditions. The distinct microbiome in the knee joint and the close host-microbe relationships within the knee joint may play a decisive role in the development of osteoarthritis and periprosthetic joint infection.

Plasma D-Dimer Is Noninferior to Serum C-Reactive Protein in the Diagnosis of Periprosthetic Joint Infection

BACKGROUND

No single test has demonstrated absolute accuracy in the diagnosis of periprosthetic joint infection (PJI). Serological markers are often used as screening tools in the workup of patients with suspected PJI. This study aimed to determine the diagnostic utility of plasma D-dimer for PJI in a variety of clinical scenarios.

METHODS

This prospective study enrolled 502 patients undergoing revision hip or knee arthroplasty. PJI was defined per a modified version of the 2018 International Consensus Meeting (ICM) criteria. Plasma D-dimer, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and fibrinogen were measured preoperatively. Receiver operating characteristic curves were used to assess the utility of each biomarker in the diagnosis of PJI. Pairwise comparison with Bonferroni correction was performed to determine whether the differences in areas under the curve (AUCs) between the markers were significant.

RESULTS

Of the 412 patients included, 317 (76.9%) did not have an infection (aseptic group) and 95 (23.1%) had an infection (PJI group). All 4 serological markers, D-dimer (AUC, 0.860; sensitivity, 81.3%; specificity, 81.7%), CRP (AUC, 0.862; sensitivity, 90.4%; specificity, 70.0%), ESR (AUC, 0.833; sensitivity, 73.9%; specificity, 85.2%), and fibrinogen (AUC, 0.798; sensitivity, 74.7%; specificity, 75.4%), demonstrated comparable accuracy for the diagnosis of PJI (all p > 0.05). When examining the performance of the different inflammatory markers in diagnosing infection caused by indolent organisms, D-dimer demonstrated the highest sensitivity at 93.8%.

CONCLUSIONS

We found that plasma D-dimer was noninferior to serum CRP and ESR in the diagnosis of PJI and may be a useful adjunct when screening patients undergoing revision total joint arthroplasty.

LEVEL OF EVIDENCE

Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Should We Aim to Help Patients "Feel Better" or "Feel Good" After Total Hip Arthroplasty? Determining Factors Affecting the Achievement of the Minimal Clinically Important Difference and Patient Acceptable Symptom State

BACKGROUND

Recent attempts have been made to use preoperative patient-reported outcome measure (PROM) thresholds as prior authorization criteria based on the assumption that patients who have higher baseline scores are less likely to achieve the minimal clinically important difference (MCID). This study aimed to identify factors affecting the achievement of MCID and patient acceptable symptom state (PASS) after total hip arthroplasty (THA), and to determine the overlap between the two outcomes.

METHODS

We identified 3,581 primary, unilateral THAs performed at a single practice in 2015-2019. PROMs including Hip Disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS-JR) and 12-item Short Form Health Survey were collected preoperatively and 1-year postoperatively. The likelihood of attaining PASS according to attainment of MCID was assessed. Multivariable regression was used to identify independent predictors of MCID and PASS.

RESULTS

In total, 79.8% achieved MCID and 73.6% achieved PASS for HOOS-JR. Approximately 1 in 7 patients who achieved MCID did not eventually achieve PASS. Worse preoperative HOOS-JR (odd ratio 0.933) was associated with MCID attainment. Better preoperative HOOS-JR (odd ratio 1.015) was associated with PASS attainment. Men, lower body mass index, better American Society of Anesthesiologists score, and better preoperative 12-item Short Form Health Survey mental score were predictors of MCID and PASS. Age, race, ethnicity, Charlson Comorbidity Index, and smoking status were not significant predictors.

CONCLUSION

Preoperative PROMs were associated with achieving MCID and PASS after THA, albeit in opposite directions. Clinicians should strive to help patients "feel better" and "feel good" after surgery. Preoperative PROMs should not solely be used to prioritize access to care.

Time to Positivity of Cultures Obtained for Periprosthetic Joint Infection

BACKGROUND

Despite its well-established limitations, culture remains the gold standard for microbial identification in periprosthetic joint infection (PJI). However, there are no benchmarks for the time to positivity (TTP) on culture for specific microorganisms. This study aimed to determine the TTP for pathogens commonly encountered in PJI.

METHODS

This retrospective, multicenter study reviewed prospectively maintained institutional PJI databases to identify patients who underwent hip or knee revision arthroplasty from 2017 to 2021 at 2 tertiary centers in the United States and Germany. Only patients who met the 2018 International Consensus Meeting (ICM) criteria for PJI and had a positive intraoperative culture were included. TTP on culture media was recorded for each sample taken intraoperatively. The median TTP was compared among different microbial species and different specimen types. Data are presented either as the mean and the standard deviation or as the median and the interquartile range (IQR).

RESULTS

A total of 536 ICM-positive patients with positive cultures were included. The mean number of positive cultures per patient was 3.9 ± 2.6. The median TTP, in days, for all positive cultures was 3.3 (IQR, 1.9 to 5.4). Overall, gram-negative organisms (TTP, 1.99 [1.1 to 4.1]; n = 225) grew significantly faster on culture compared with gram-positive organisms (TTP, 3.33 [1.9 to 5.8]; n = 1,774). Methicillin-resistant Staphylococcus aureus (TTP, 1.42 [1.0 to 2.8]; n = 85) had the fastest TTP, followed by gram-negative rods (TTP, 1.92 [1.0 to 3.9]; n = 163), methicillin-sensitive Staphylococcus aureus (TTP, 1.95 [1.1 to 3.3] n = 393), Streptococcus species (TTP, 2.92 [1.2 to 4.3]; n = 230), Staphylococcus epidermidis (TTP, 4.20 [2.4 to 5.5]; n = 555), Candida species (TTP, 5.30 [3.1 to 10]; n = 63), and Cutibacterium acnes (TTP, 6.97 [5.9 to 8.2]; n = 197). When evaluating the median TTP according to specimen type, synovial fluid (TTP, 1.97 [1.1 to 3.1]; n = 112) exhibited the shortest TTP, followed by soft tissue (TTP, 3.17 [1.4 to 5.3]; n = 1,199) and bone (TTP, 4.16 [2.3 to 5.9]; n = 782).

CONCLUSIONS

To our knowledge, this is the first study to examine the TTP of common microorganisms that are known to cause PJI. Increased awareness of these data may help to guide the selection of appropriate antimicrobial therapy and to predict treatment outcomes in the future. Nonetheless, additional studies with larger cohorts are needed to validate these benchmarks.

LEVEL OF EVIDENCE

Diagnostic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Surgeons Experience More Physiologic Stress and Strain During Revision Than Primary Total Joint Arthroplasty

BACKGROUND

Revision total knee arthroplasty (rTKA) and total hip arthroplasty (rTHA) procedures are more complex than primary TKA and THA, but their physiologic burden to the surgeon has not been quantified. While rTKA and rTHA have longer operative times, it is unknown whether differences exist in stress and strain compared to primary TKA and primary THA. The study was conducted to elicit whether differences exist in surgeon physiological response while performing rTKA and rTKA compared to primary TKA and primary THA.

METHODS

We evaluated a prospective cohort study of 70 consecutive cases (23 primary TKAs, 12 primary THAs, 16 rTKAs, and 19 rTHAs). Two high-volume fellowship-trained arthroplasty surgeons wore a smart vest that recorded cardiorespiratory data while performing primary THA, primary TKA, rTHA, and rTKA. Heart rate (beats/minute), stress index (correlates with sympathetic activation), respiratory rate (respirations/minute), minute ventilation (L/min), and energy expenditure (Calories) were collected for every case, along with patient body mass index (kilograms/meter²) and working operative time (minutes). T-tests were used to assess for differences between the two groups.

RESULTS

Compared to primary TKA, performing rTKAs had a significantly higher surgeon stress index (17 versus 15; P = .035), heart rate (104 versus 99; P = .007), energy expenditure per case (409 versus 297; P = .002), and a significantly lower heart rate variability (11 versus 12; P = .006). Compared to primary THA, performing rTHA had a significantly higher energy expenditure per case (431 versus 307; P = .007) and trended towards having a higher surgeon stress index (16 versus 14; P = .272) and a lower heart rate variability (11 versus 12; P = .185), although it did not reach statistical significance.

CONCLUSION

Surgeons experience higher physiological stress and strain when performing rTKA and rTHA compared to primary TKA and primary THA. This study provides objective data on what many surgeons feel and should promote further research on the specific stress and strain felt by surgeons who perform revision arthroplasty procedures.

The Paradox of Patient-Reported Outcome Measures: Should We Prioritize "Feeling Better" or "Feeling Good" After Total Knee Arthroplasty?

BACKGROUND

The use of preoperative patient-reported outcome measure (PROM) thresholds for patient selection in arthroplasty care has been questioned recently. This study aimed to identify factors affecting achievement of the minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) after total knee arthroplasty (TKA) and determine the overlap between the two outcomes.

METHODS

We identified 1,239 primary, unilateral TKAs performed at a single institution in 2015-2019. PROMs including the Knee injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) and 12-item Short Form Health Survey (SF-12) were collected preoperatively and 1-year postoperatively. The likelihood of attaining PASS as per attainment of MCID was assessed. A multivariable regression was used to identify predictors of MCID and PASS.

RESULTS

In total, 71.3% achieved MCID and 75.5% achieved PASS for KOOS-JR. Only 7.7% achieved MCID but not PASS, whereas almost twice this number did not achieve MCID but did achieve PASS (11.9%). Poorer preoperative KOOS-JR (OR 0.925), better SF-12 physical (OR 1.025), and mental (OR 1.027) were associated with MCID attainment. In contrast, better preoperative KOOS-JR (OR 1.030) and SF-12 mental (OR 1.025) were associated with PASS attainment. Age, gender, race, ethnicity, body mass index, Charlson index, American Society of Anesthesiologists classification, and smoking status were not significant predictors.

CONCLUSION

Preoperative PROMs were associated with achieving MCID and PASS after TKA, albeit some positively and some negatively. In the era of value-based care, clinicians should not only strive to help patients "feel better" but also ensure that patients "feel good" after surgery. This study does not support the use of PROMs in prioritizing access to care.

Minimum Five-Year Outcomes of Modular Dual Mobility in Primary Total Hip Arthroplasty

BACKGROUND

Using a modular dual-mobility (MDM) bearing in primary total hip arthroplasty (THA) has not been widely evaluated. The purpose of this study is to evaluate clinical outcomes and survivorship following MDM bearings in primary THA.

METHODS

We used our registry database for patients with an MDM bearing on primary THA, performed by 6 surgeons through supine direct lateral or direct anterior approach. MDM bearings were used most often when impingement or subluxation was present intraoperatively despite proper component position. Another indication was a patient with planned activities who might be at a higher risk of instability postoperatively.

RESULTS

A total of 127 MDM bearings were used in primary THA in 119 patients. Mean follow-up was 6.77 years (range 5-8.9). Five hips were revised, none of which were due to MDM bearing failure. Preoperative Hip dysfunction and Osteoarthritis Outcome Score for Joint Replacement, Veterans RAND/Short Form 12 Physical Health Score and Mental Health Score increased from 25.81 to 52.40 (P < .0001), 30.42 to 44.50 (P < .0001), and 36.21 to 52.70 (P < .0001) at latest completed survey follow-up, respectively.

CONCLUSION

This MDM bearing shows excellent functional outcomes at a minimum 5 years of follow-up with no bearing-related failures. It can be an excellent choice in primary THA specifically in females where the use of increased head size to prevent instability is not possible due to anatomical restrictions and liner thickness.

Mental health first aid for the UK Armed Forces

Education programmes in mental health literacy can address stigma and misunderstanding of mental health. This study investigated self-rated differences in knowledge, attitudes and confidence around mental health issues following participation in a bespoke Mental Health First Aid (MHFA) training course for the Armed Forces. The mixed methods approach comprised quantitative surveys and qualitative interviews. A survey, administered immediately post-training (n = 602) and again at 10-months post-attendance (n = 120), asked participants to rate their knowledge, attitudes and confidence around mental health issues pre- and post-training. Quantitative findings revealed a significant increase in knowledge, positive attitudes and confidence from the post-training survey which was sustained at 10-months follow-up.Semi-structured telephone interviews (n = 13) were conducted at follow-up, 6-months post-attendance. Qualitative findings revealed that participation facilitated an ‘ambassador’ type role for participants. This study is the first to have investigated the effect of MHFA in an Armed Forces community. Findings show participants perceived the training to increase knowledge regarding mental health and to enhance confidence and aptitude for identifying and supporting people with mental health problems. Results suggest that such an intervention can provide support for personnel, veterans and their families, regarding mental health in Armed Forces communities.

'Artlift' arts-on-referral intervention in UK primary care: updated findings from an ongoing observational study

Background

Arts for health interventions are an accepted option for medical management of mental wellbeing in health care. Updated findings are presented from a prospective longitudinal follow-up (observational) design study of an arts on referral programme in UK general practice, over a 7-year period (2009-2016).

Methods

Primary care process and mental wellbeing outcomes were investigated, including progress through the intervention, changes in mental wellbeing, and factors associated with those outcomes. A total of n =1297 patients were referred to an eight or 10-week intervention over a period from 2009 to 2016. Patient sociodemographic information was recorded at baseline, and patient progress (e.g. attendance) assessed throughout the intervention.

Results

Of all referrals, 51.7% completed their course of prescribed art (the intervention). Of those that attended, 74.7% engaged with the intervention as rated by the artists leading the courses. A significant increase in wellbeing was observed from pre- to post-intervention (t = -19.29, df =523, P < 0.001, two-tailed) for those that completed and/or engaged. A sub sample (N =103) of these referrals self-reported multi-morbidities. These multiple health care service users were majority completers (79.6%), and were rated as having engaged (81.0%). This group also had a significant increase in well-being, although this was smaller than for the group as a whole (t = -7.38, df =68, P < 0.001).

Conclusion

Findings confirm that art interventions can be effective in the promotion of well-being for those that complete, including those referred with multi-morbidity, with significant changes in wellbeing evident across the intervention periods.

Molecular battles between plant and pathogenic bacteria in the phyllosphere

The phyllosphere, i.e., the aerial parts of the plant, provides one of the most important niches for microbial colonization. This niche supports the survival and, often, proliferation of microbes such as fungi and bacteria with diverse lifestyles including epiphytes, saprophytes, and pathogens. Although most microbes may complete the life cycle on the leaf surface, pathogens must enter the leaf and multiply aggressively in the leaf interior. Natural surface openings, such as stomata, are important entry sites for bacteria. Stomata are known for their vital role in water transpiration and gas exchange between the plant and the environment that is essential for plant growth. Recent studies have shown that stomata can also play an active role in limiting bacterial invasion of both human and plant pathogenic bacteria as part of the plant innate immune system. As counter-defense, plant pathogens such as Pseudomonas syringae pv tomato (Pst) DC3000 use the virulence factor coronatine to suppress stomate-based defense. A novel and crucial early battleground in host-pathogen interaction in the phyllosphere has been discovered with broad implications in the study of bacterial pathogenesis, host immunity, and molecular ecology of bacterial diseases.

Three phenotypes of glucosephosphate isomerase in sheep: improved staining recipe

Contrary to results published recently, we observe three, rather than two, phenotypes for the enzyme glucosephosphate isomerase (EC 5.3.1.9) from sheep. The phenotypic electrophoretic patterns conform to the patterns observed for this dimeric enzyme in other species. Genotype frequencies in a flock of Southdowns do not deviate significantly from those predicted under the assumption of the Hardy-Weinberg equilibrium. A remarkable observation is that the electrophoretically distinct phenotypes of GPI are largely or entirely obliterated by the addition of 1-10 mmol/l MgCl2 to the electrophoretic buffers. Modification of the usual staining recipe for GPI result in greater resolution and shorter staining times.

The use of genetic relationships among cattle breeds in the formulation of rational breeding policies: a re-examination of the example of the South Devon and the Gelbvieh

It has been claimed that the origin of the South Devon breed of cattle is 'unknown' and that biochemical polymorphisms '. . . indicate that Gelbvieh and South Devon had a common ancestry on the Continent and are distinct from other British breeds such as Hereford, Angus and Jersey' (Kidd et al., 1974). In fact, historical records indicate that the South Devon evolved largely from native Devon cattle and is a close relative of other English Lowland breeds such as the North Devon and Hereford. Information about crosses from other breeds makes no mention of the Gelbvieh but emphasises the contribution of Channel Island breeds, especially the Guernsey. Data for biochemical polymorphisms in the relevant breeds show agreement with the historical information and with the biogeography of the breeds involved.

Chemical classification of cattle. 1. Breed groups

From approximately 1000 papers with data on protein polymorphism in some 216 breeds of cattle, 10 polymorphic proteins were compared in means and variances of gene frequencies (arcsin p 1/2) for ten well-recognized breed groups for 196 of the breeds. The polymorphic proteins were alpha-lactalbumin, beta-lactoglobulin, caseins (alpha s1, beta and chi), serum albumin, transferrin, haemoglobin, amylase I and carbonic anhydrase II. The breed groups were North European, Pied Lowland, European Red brachyceros, Channel Island brachyceros, Upland brachyceros, primigenius-brachyceros mixed, primigenius, Indian Zebu, African Humped (with Zebu admixture), and African Humped (Sanga). The coherence within groups and the differences between groups are often impressive. Only carbonic anhydrase II fails to differentiate at least some of the major breed groups. In some cases paradoxical distributions of rare genetic variants can be explained by a more detailed inspection of breed history. The chemical data support the morphological and geographical divisions of cattle into major breed groups. There are three distinct but related brachyceros groups; for some polymorphisms the two Channel Island breeds, the Jersey and the Guernsey, are quite divergent. Although some authorities have considered the Pied Lowland as primigenius, it is a very distinct breed group.

Chemical classification of cattle. 2. Phylogenetic tree and specific status of the Zebu

Phylogenetic trees for the ten major breed groups of cattle were constructed by Farris's (1972) maximum parsimony method, or Fitch & Margoliash's (1967) method, which averages ou the deviation over the entire assemblage. Both techniques yield essentially identical trees. The phylogenetic tree for the ten major cattle breed groups can be superimposed on a map of Europe and western Asia, the root of the tree being close to the 'fertile crescent' in Asia Minor, believed to be a primary centre of bovine domestication. For some but not all protein variants there is a cline of gene frequencies as one proceeds from the British Isles and northwest Europe towards southeast Europe and Asia Minor, with the most extreme gene frequencies in the Zebu breeds of India. It is not clear to what extent the observed clines are primary or secondary, i.e., consequent to the initial migrations of cattle towards the end of the Pleistocene or consequent to the many migrations of man with his domesticated cattle. Such clines as exist are not in themselves sufficient to prove either selection versus genetic drift or to establish taxonomic ranking. Contrary to some suggestions in the literature, the biochemical evidence supports Linnaeus's original conclusions: Bos taurus and Bos indicus are distinct species.

Distance measurements in the borderline region of applicability of CW EPR and DEER: a model study on a homologous series of spin-labelled peptides

Inter-spin distances between 1 nm and 4.5 nm are measured by continuous wave (CW) and pulsed electron paramagnetic resonance (EPR) methods for a series of nitroxide-spin-labelled peptides. The upper distance limit for measuring dipolar coupling by the broadening of the CW spectrum and the lower distance limit for the present optimally-adjusted double electron electron resonance (DEER) set-up are determined and found to be both around 1.6-1.9 nm. The methods for determining distances and corresponding distributions from CW spectral line broadening are reviewed and further developed. Also, the work shows that a correction factor is required for the analysis of inter-spin distances below approximately 2 nm for DEER measurements and this is calculated using the density matrix formalism.

Empowerment among Latina nurses in Mexico, New York and Indiana

BACKGROUND

Increasing empowerment among nurses may help retain nurses and increase the international workforce. There are very few cross-national studies of nurse empowerment reported in the professional literature.

AIM

To conduct a cross-national exploratory study testing a theoretical model of nurse empowerment.

DESIGN

Descriptive survey of three convenience samples of graduate Latina nurses in Monterrey, Mexico, New York City and Indiana.

METHODS

Data were collected using self-administered questionnaires. The Klakovich Reciprocal Empowerment Scale (RES) was translated into Mexican-Spanish using a translation back-translation technique. Variables for the study included empowerment, years of experience, job satisfaction and intent to stay. Frequency distributions and descriptive statistics were used to analyse the data.

FINDINGS

Empowerment involves reciprocity between the leader and follower, a common vision and synergy about the work, and a sense of ownership in the work site. Mexican nurses scored significantly higher on synergy than Latina nurses in New York and Indiana. Empowerment is related to job satisfaction, age and years of employment.

CONCLUSIONS

Results indicate the usefulness of the RES instrument for Latina nurses and the need for further research with larger samples. Cross-national research provides culturally sensitive information. Such research partnerships facilitate modelling the importance of nursing research to graduate nurses and students.

Hospital conversion foundations. Issues in creation, operation, and evaluation

A major healthcare transformation in the United States is the conversion of nonprofit hospitals to for-profit entities, and the creation of hospital conversion foundations for the nonprofit charitable assets, which now exceeds $9 billion. Because less than 21% of the 525 hospitals converting from nonprofit to for-profit ownership have established a hospital conversion foundation, the public's monetary losses are considerable. This article examines some of the key legal and organizational issues related to hospital conversion foundations including factors related to establishing fair value of the converting hospital, foundation mission, use of conversion revenue, governance, and evaluation.

Evidence of a functional alpha7-neuronal nicotinic receptor subtype located on motoneurons of the dorsal motor nucleus of the vagus

In vitro autoradiography using 125I-alpha-bungarotoxin (alpha-BGTx) and anti-alpha7 immunohistochemistry were performed on the dorsal motor nucleus of the vagus (DMV) of sham and chronically vagotomized rats to determine whether the alpha7-nicotinic acetylcholine receptor (nAChR) is located postsynaptically on DMV neurons whose axons contribute to the vagus nerve. Intense bilateral 125I-alpha-BGTx binding and anti-alpha7 immunostaining were observed in coronal brain sections containing the DMV of sham-vagotomized animals. Unilateral cervical vagotomy resulted in ipsilateral losses of 125I-alpha-BGTx binding and anti-alpha7 immunostaining from the DMV. Simultaneous staining of rat brainstem sections with anti-alpha7 and anti-choline acetyltransferase (ChAT) antibodies (to identify cholinergic DMV neurons that project into the vagus nerve) revealed that every DMV neuron that was stained for ChAT showed alpha7-staining as well. In vagotomized animals, no ChAT-positive neurons expressing alpha7-nAChRs remained in the ipsilateral DMV. We conclude that the alpha7-nAChR subtype is located postsynaptically on DMV neurons. To test whether the alpha7-nAChR is similar to the alpha7-homomeric nAChR, experiments were performed in anesthetized rats, and compounds were microinjected into the DMV while monitoring intragastric pressure (IGP). alpha-BGTx and strychnine antagonized nicotine-induced increases in IGP; no antagonism was observed with methyllycaconitine, a compound known to block the homomeric alpha7-nAChR subtype. Recovery from alpha-BGTx-induced antagonism of the nicotine response was observed. We conclude that there is a nAChR containing the alpha7-subunit in the DMV that is different from the homomeric alpha7-nAChR subtype.

Pulmonary artery trauma due to balloon dilation: recognition, avoidance and management

OBJECTIVES

We reviewed the management and outcome of patients experiencing pulmonary artery (PA) trauma during balloon dilation (BD).

BACKGROUND

Balloon dilation of the PA is important in the management of peripheral pulmonary stenosis. Successful BD requires a controlled tear of the PA; excessive tearing can produce complications ranging from pseudoaneurysms to rupture and death. The incidence and optimum management for such complications are unreported.

METHODS

All records of patients who underwent branch PA dilation between June 1984 and October 1997 were reviewed; those with a significant complication were analyzed.

RESULTS

Of 1,286 catheterizations in 782 patients, PA trauma (excluding isolated pulmonary edema and PA aneurysms) was identified in 29 catheterizations in 26 patients. Tears occurred distal to the area of stenosis in most cases (62%). Intensive medical management, with and without catheter directed therapy, was employed. The damaged PA was successfully coil embolized in five patients, four of whom survived; temporary balloon occlusion did not prevent death in two patients. There were six deaths from pulmonary hemorrhage. A case control analysis demonstrated that PA trauma was significantly associated with pulmonary hypertension.

CONCLUSIONS

Pulmonary artery trauma associated with BD occurs mostly distal to the site of narrowing, is associated with underlying pulmonary hypertension and is frequently (5/12 or 42%) fatal in those with unconfined tears. Intensive management strategies as well as attention to distal balloon position may reduce incidence and mortality. Coil occlusion of the damaged PA appears to be a valuable strategy to prevent fatal hemorrhage.

Problem-based learning for nursing: integrating lessons from other disciplines with nursing experiences

Problem-based learning (PBL) is a philosophy and teaching method that structures knowledge in clinical contexts, strengthens motivation to learn, develops clinical reasoning skills, and enhances self-directed and life-long learning. During the past 30 years, PBL has been implemented in schools of medicine worldwide, including 100 of the 126 schools in the United States. This article reviews the international PBL literature and focuses on the key aspects of this paradigm in educating health professionals: recent history and worldwide diffusion, basic characteristics and rationale, typical case presentation, student and tutor roles, and data-based outcomes. Conclusions from selected meta-analytic studies of assessment are described and discussed. The potential of PBL for nursing education is examined. Key implementation issues are identified, including the challenge to persuade faculty to move from efficient teaching to effective learning.

Hospital ownership, performance, and outcomes: assessing the state-of-the-science

OBJECTIVE

This study 1) identified the research evidence; 2) assessed the state-of-the-science surrounding hospital ownership, performance, and outcomes in acute care hospitals in the United States; and 3) identified measurable components of hospital performance and outcomes for the organization, patient, and community.

BACKGROUND

As the size of the nonprofit sector decreases and the size of the for-profit sector increases, hospital ownership warrants examination. Most research has focused on either ownership and performance or ownership and outcomes, rather than the potential interaction of all three variables.

METHODS

A comprehensive, computerized search of the healthcare research literature yielded 69 data-based references published between 1985 and 1999. Coding sheets were developed to abstract the articles. Analysis involved synthesizing the research evidence for each of the three major variables and their components.

RESULTS

Hospital ownership has an impact on hospital performance in relation to system operations; costs, prices, and financial management practices; and personnel issues. Organizational outcomes are similar among hospital ownership types in relation to increasing administrative costs and overall mediocre efficiency. Organizational outcomes differ among hospital ownership types in relation to nursing staff mix and professional satisfaction. The association of hospital ownership with patient outcomes varies depending on the dimension measured. The evidence is mixed or inconclusive regarding hospital ownership and access to care, morbidity, and mortality. The association of hospital ownership and adverse events is consistently supported. Hospital ownership status has an impact on the type and magnitude of community benefits. Differences among the three hospital ownership types are minimized in a competitive market.

CONCLUSIONS

This study reinforces the position that nurse researchers need to include hospital ownership as an important structural variable in their studies of hospital-based nursing. Examining the conceptual links between ownership, performance, and outcomes requires the integration of macro-level and micro-level theory.

Chemokines and chemokine receptors in the pathogenesis of multiple sclerosis

In recent years we have seen growing evidence for the role of chemokines in the pathogenesis of several infectious and non-infectious inflammatory CNS disease states, including Multiple Sclerosis (MS) and its animal model, experimental allergic encephalomyelitis (EAE). An increase in proinflammatory chemokines has been associated with demyelinating lesions and clinical neurological dysfunction in patients with MS; these chemokines could be potential targets for MS therapy. Besides a clearly defined role in mediating leukocyte migration, these and other chemokines may act as immunoregulatory molecules in the driving to Th1/Th2 responses, switch of cytokine profiles, and the induction of tolerance. Since chemokine receptors have now been identified on macrophages, microglia, astrocytes, and endothelial cells as well as neurons in the CNS, chemokine/receptor interactions may mediate functional responses in a variety of CNS cell types during the course of inflammatory disease states. Therefore, clarification of the roles of chemokines and their receptors in the pathogenesis of EAE and MS will be useful in establishing immunotherapeutic strategies for these neurological autoimmune disorders.

Using problem-based learning to redesign nursing administration masters programs

Problem-based learning (PBL) is offered as an appropriate pedagogy to prepare nurse managers for the uncertainties of future administrative practice. It is a student-centered, experiential learning strategy aimed at developing clinical reasoning, structuring knowledge in real-life contexts, motivating learning, and developing self-learning skills. Health professions and business schools report positive feedback from their stakeholders after adopting this new learning paradigm.

Left superior vena cava connection to unroofed coronary sinus associated with positional cyanosis: successful transcatheter treatment using Gianturco-Grifka vascular occlusion device

A persistent left superior vena cava connection to an unroofed coronary sinus is a rare cardiac anomaly that is associated with a variable degree of cyanosis. We report an infant with this condition and the unusual feature of cyanosis dependent on head position. When the patient's head was rotated to the left, he developed severe stenosis of the left internal jugular vein, enlarged cervical collateral veins that connected to the right superior vena cava and had an oxygen saturation 95%. When the patient's head was rotated to the right, the left internal jugular vein was widely patent and systemic oxygen saturation decreased to 87%. There was no right ventricular volume overload. Temporary occlusion of the left superior vena cava documented tolerable proximal venous pressure. Cyanosis was relieved by transcatheter closure of the left superior vena cava with a Gianturco-Grifka vascular occlusion device. Cathet. Cardiovasc. Intervent. 48:369-373, 1999.

Hospital consolidation. Applying stakeholder analysis to merger life-cycle

Nearly three of every five hospitals in the United States have been involved in some form of consolidation during the past 5 years. Within this turbulent hospital merger environment, nurse executives are confronted with organizational, professional, and personal decisions. Stakeholder analysis is offered as one strategy to facilitate effectiveness throughout the hospitals' merger life-cycle.

Leaflet development, induction time, and medium influence somatic embryogenesis in peanut (Arachis hypogaea L.)

Factors affecting somatic embryogenesis in peanut (Arachis hypogaea L.) using leaflet explants of seedlings obtained from aseptically germinated embryo axes were evaluated. Somatic embryogenesis was influenced by developmental stage, leaflet size, induction medium, and time on induction medium. Leaflets that were 5-7 mm long had a greater embryogenic response than smaller or larger leaflets. Percent embryogenesis and mean number of embryos were related to the developmental stage of germinating seedlings. A greater response was obtained if leaflets were folded and closely appressed. Preselection of leaflets increased percent embryogenesis from 21% up to 67%. As leaflets unfolded, embryogenesis decreased; open leaflets lost the potential for embryogenesis. The optimal induction conditions were a 7-day incubation period on Murashige and Skoog medium with 136 μM 2,4-dichlorophenoxyacetic acid and 0.93 μM kinetin. Somatic embryos germinated to form plants that exhibited a normal morphology.

Acute stroke patients comparing outcomes with and without case management

Stroke represents a major human and economic challenge to society. The literature suggests that interdisciplinary clinical pathways maximize stroke patient outcomes, whether care is delivered in a designated stroke unit or in a general medical service. In this article, the authors describe the case management model implemented at Columbus Regional Hospital, a 325-bed rural referral hospital in southeastern Indiana. A retrospective chart review compared 23 patients with non-hemorrhagic strokes using two different models of care delivery: unit-based nursing case management and standard nursing care. Differences in outcomes are reported in relation to interdisciplinary utilization, timeliness of referrals, patient education, discharge dispositions, home safety assessments, next-site-of-care communications, length of hospital stay, and patient satisfaction.

Differentiated nursing practice: assessing the state-of-the-science

The authors present their findings following an exhaustive literature review of research on differentiated nursing practice (DNP) that used a number of tools to measure various aspects of DNP that are applicable across the health care delivery continuum. Issues related to DNP include: optimal nursing care, matching patient needs with nurse competencies, effective use of nursing resources, equitable compensation, career satisfaction, loyalty to employers, and enhanced prestige of the nursing profession. One 1992 Massachusetts study of a three-role oncology unit project (including patient care manager, clinical nurse, and patient care technician), showed positive change in five criteria including: standards of nursing care, actual care hours, average labor costs, job satisfaction and patient satisfaction. A 1990 Arizona study that included unit assistants concluded that DNP supported a decline in the use of supplemental staff and staff overtime which led to cost savings, and increases in the actual hours of care and nurse satisfaction.

Organizational effectiveness: toward an integrated model for schools of nursing

Assessing the quality of academic institutions involves much more than the opinions of peers or experts. Examination of the organizational effectiveness of schools of nursing has been neglected. Current emphasis on assessing educational outcomes has diverted attention from the construct, organizational effectiveness, and more comprehensive theory-driven approaches to evaluation. This review of the organizational effectiveness literature focuses on the major assessment models: goal attainment, human relations, open systems, internal processes, culture, and life cycle. Attention is given to the influence of organizational maturation on an integrated model of organizational effectiveness. Selected macrolevel studies of schools of nursing are examined, and an agenda for nursing research is proposed.

Quality assurance procedure on a Huestis Styro-former--stay on the cutting edge

A review of variations in block positions on port film vs. simulator film at The Nashua Regional Cancer Center, Nashua, NH, prompted the development of a method of measuring the accuracy of hot wire cut molds vs. a "test" film. The procedure is done at a minimum of once a year, or when accuracy of the block cuts are suspect. This simple test insures a high degree of confidence that the resulting cut molds are appropriate for the clinical situation and the need to recut blocks as a result of an out-of-tolerance Huestis Styro-former is kept to a minimum.

Improvements in rooting regenerated safflower (Carthamus tinctorius L.) shoots

A continuing obstacle for regenerating safflower (Carthamus tinctorius L.) plants from cultured explants or callus has been a reliable method for rooting shoots. For shoots directly regenerated from primary explants, 76% of shoots rooted after a 7-d exposure to 10 mg/1 indole-3-butyric acid. Auxin source, concentration or exposure time did not greatly affect root formation or morphology, but strongly affected callus production. Shoots infected with Agrobacterium rhizogenes produced massive numbers of fibrous roots, but shoots did not elongate or survive transfer to soil. Shoot hyperhydricity symptoms were reduced by including 1 g/1 activated charcoal in rooting media. The optimal protocol for inducing root formation consisted of a 7-d exposure to 10 mg/l indole-3-butyric acid in root induction media, followed by incubation in media containing 15 g/l sucrose and 1 g/1 activated charcoal for 21 d.

Directors of Continuing Nursing Education: A National Survey of Educational Needs

Advancing technology and healthcare reform necessitate continuing nursing education to maintain competence. This study assesses the knowledge and skills needed to function as a director of continuing nursing education in a variety of settings, estimates the supply of qualified applicants for vacant director positions, and identifies essential academic needs of someone preparing for the director's position.

When to begin a doctoral programme in nursing

The future of the nursing profession is strengthened by the expansion of nursing science and its integration with nursing practice, the hallmarks of doctoral education. Launching a doctoral programme in nursing is a monumental venture into the main stream of higher education; consequently, the readiness to begin such an effort must be carefully assessed.

High frequency somatic embryogenesis in peanut (Arachis hypogaea L.) using mature, dry seed

Peanut (Arachis hypogaea L.) somatic embryos were produced from the embryo axes of mature, dry seeds of cultivar GK-7. Percent embryogenic explants ranged from 88-100% using 10-40 mg/1 of 2,4-D in the induction medium. Neither 2,4-D concentration nor photoperiod during the induction period had a large effect on percent embryogenesis, mean number of embryos per explant, or embryo morphology. However, embryos obtained from cultures grown in the dark were easier to remove from the explant than those under a 16-h photoperiod. Somatic embryos developed on the epicotyl portion of the embryo axis, primarily on the young, expanding leaves. A survey of 14 genotypes indicated that genotype had a large influence on embryogenic capacity, with all genotypes being embryogenic to some extent. The ability to recover somatic embryos from axes of harvested, stored seeds represents significant advantages for the establishment of peanut embryogenic cultures, including the use of simple sterilization procedures and a constant source of explant tissue.

Influence of photoperiod and medium formulation on peanut somatic embryogenesis

Somatic embryos were produced from peanut (Arachis hypogaea L.) immature zygotic cotyledons. Comparisons were made of the level of α-naphthaleneacetic acid during induction, nitrogen formulation of the medium, and photoperiod. Over 70% embryogenesis was obtained regardless of NAA level used. Percent embryogenesis and number of embryos were markedly lower in explants induced on NAA compared to 2,4-D. Embryo production was not greatly affected by either the use of Murashige & Skoog versus Finer & Nagasawa salts or light versus dark culture conditions. However, embryo morphology was noticeably affected by photoperiod. Embryos produced under a 16 h photoperiod were tough, woody and difficult to separate for subsequent germination and conversion. Those produced under a 0-h photoperiod were succulent and pliable.

Master's degree nursing education: state of the art

This study examines the state of the art in master's nursing education in the United States in light of projected national trends in the health care delivery system. The specific questions addressed are: What are the general characteristics of master's programs, including admission requirements and prerequisites, program requirements, major and minor areas of clinical concentration, functional role preparation, and career mobility options? What is the curricular organization, particularly with respect to required core courses? Is there a difference between master's programs in schools with a doctoral program in nursing and those with master's programs only? Is there a difference between master's programs with public support and master's programs with private support? Data were collected from 175 accredited master's programs in 1990. Study results and the projected trends derived from Nursing's Agenda for Health Care Reform, Healthy People 2000: National Health Promotion and Disease Prevention Objectives, and Healthy America: Practitioners for 2005 provide the foundation for recommendations. Recommendations are organized around communication and curricular issues that master's nursing education needs to address as the profession approaches the 21st century.

Somatic embryogenesis and plant regeneration from leaflets of peanut, Arachis hypogaea

Somatic embryos were induced on peanut (Arachis hypogaea) leaflets from aseptically germinated embryo axes. Leaflet size influenced percent somatic embryogenesis; 5-8 mm long cut leaflets were superior to 2-3 mm long uncut leaflets. Maximum embryogenesis of 14.6% was obtained after a 15 d incubation on induction medium (modified MS with B5 vitamins, 30 g/l sucrose, 4 g/l Gel-Gro, 40 mg/l 2,4-D +0.2 mg/l kinetin) followed by transfer to a secondary medium with 5 mg/l 2,4-D+0.2 mg/l kinetin. Primary somatic embryos were fused along the axes with no distinct cotyledons, but secondary embryos had single axes with two cotyledons. Other treatments had lower percent embryogenesis, no secondary embryogenesis, and embryos with single axes with two cotyledons. Some somatic embryos converted into normal plants capable of greenhouse survival.

Genetic variation in the African rodent subfamily Otomyinae (Muridae). II. Chromosomal changes in some populations of Otomys irroratus

Chromosome-banding studies have been carried out on 31 specimens of Otomys irroratus from six localities. Light-microscope preparations of chromosomes were obtained from cultures of fibroblasts, spleen lymphocytes, peripheral blood lymphocytes, and directly from bone marrow. Karyotypic variability, both numerical and morphological, was detected in three populations. Diploid numbers ranged from 2n = 23 to 2n = 32. Intrapopulation differences were chiefly caused by variation in the number of copies in two pairs of small, biarmed, partly heterochromatic autosomes suggestive of B chromosomes. A major morphological variation in the karyotypes involved the presence of seven pairs of biarmed autosomes with totally heterochromatic short arms in the populations distributed to the west of 26 degrees 57' E. To the east of this longitude, populations of this species exhibited mostly acrocentric autosomes. G-banding patterns of these karyotypes and those of a karyotype from a previous study (Robinson and Elder, 1987) were compared. A chromosome originating from a tandem fusion, possibly leading to partial reproductive isolation, was found in one population. Possible implications of these results for mechanisms of speciation are discussed.