The potential of suspended chitosan nanoparticles as a surgical irrigation fluid

In this study, we sought to synthesize chitosan nanoparticles (CS-NPs) and characterize their morphology, efficacy in inhibiting bacterial attachment, and efficacy in eradicating bacteria established on implantable hardware. CS-NPs possess desirable properties, including antibacterial properties in biofilm-mediated infections. CS-NPs were produced using ionic gelation and characterized via scanning electron microscope imaging. Staphylococcus aureus was incubated with CS-NPs at various concentrations and compared to a 1% povidone-iodine with 1% H2 O2 control in 24-well plates. Stainless steel bone screws were placed in six-well plates and inoculated with S. aureus. After 24 h, the screws were transferred to one of three solutions (saline, 40 mg/mL CS-NP, or 1% povidone-iodine with 1% H2 O2 ). Four screws from each group were vortexed in saline and plated. The remaining screw from each group was prepped and imaged to map the location of persistent bacteria. Synthesized CS-NPs had a mean diameter of 0.39 ± 0.13 μm and circularity of 0.87 ± 0.05. The percent inhibition of bacterial attachment was 73% at 20 mg/mL, 73% at 30 mg/mL, 75% at 40 mg/mL, 79% at 50 mg/mL, and 78% at 60 mg/mL. When compared to saline, the 40 mg/mL CS-NP solution reduced bacteria on the screws by 76%. No bacteria were retrieved from the 1% povidone-iodine with 1% H2 O2 group. This study demonstrated that CS-NP solution effectively inhibited S. aureus bacterial attachment and was more effective than saline in eradicating bacteria from orthopedic hardware, suggesting that CS-NPs have the potential for prevention and treatment of musculoskeletal infections as a component of an intraoperative surgical irrigation solution.

Do Ultraviolet Air Disinfection Units Reduce Contamination by Particulates in Total Knee Replacement Procedures?

BACKGROUND

Prosthetic joint infections have become the leading cause of joint replacement failure. The primary sources of contamination are skin flora and bacteria from airborne particles. Portable ultraviolet air disinfection units are used in the Operating Room (OR) to prevent contamination from airborne particles; however, their effectiveness is not proven. The purpose of this study was to compare the rate of contamination of sites with and without Ultraviolet (UV) air disinfection units during active surgeries.

METHODS

Sedimentation rates of viable particles were measured during 40 primary TKA procedures. Half of the procedures were performed with ultraviolet air disinfection units. Air-borne particles were collected on nitrocellulose membranes at 5 locations within the OR. After incubation, all microbial colonies were counted and the sedimentation rates were reported in CFUs/m²/hr. 10 additional trials were performed in an empty OR with no staff present.

RESULTS

The average contamination rate of all sites was 22 ± 1.1 CFUs/m²/hr in the empty OR vs. 21.3 ± 4.6 CFUs/m²/hr with UV units and 20.3 ± 4.9 CFUs/m²/hr without (P = .03, P = .03, P = .964). Viable contaminates were found in the sterile field in 25% of UV cases vs 45% non-UV. These differences were not statistically significant. There were differences found however, according to the number of staff in the room (6 vs 7 staff: P = .036, 6 vs 8 staff: P = .004).

CONCLUSION

There was no statistical difference in contamination rate with the usage or non-usage of UV units. These 40 cases shows that the largest variables affecting the contamination rate were the number of staff present and size of the OR.

Micromotion and Migration of Cementless Tibial Trays Under Functional Loading Conditions

BACKGROUND

The outcome of cementless total knee arthroplasty (TKA) relies on successful bony ingrowth into the implant surfaces. Failures due to aseptic loosening are still reported, especially in younger and more active patients. The objective of this study is to quantify the micromotion of a commercially available design of cementless tibial tray under loading conditions simulating walking and stair descent.

METHOD

A commercially available design of cementless total knee arthroplasty was implanted in 7 cadaveric knees which were preconditioned with 500 cycles of 0°-100° flexion under a vertical load of 1050 N in a custom-built, multiaxial functional activity simulator. This was followed by application of the peak forces and moments occurring during walking and stair descent. During each loading procedure, 3-dimensional motion at the bone-prosthesis interface was measured using digital image correlation.

RESULTS

The tray migrated 101 ± 25 μm on average during preconditioning, which was dominated by rotation in the sagittal plane (92% of total migration), combined with posterior translation (28%) and minimal rotation in the transverse plane (14%). The migration varied 2.7-fold (61-167 μm) between the 6 measurement zones. Stair descent produced significantly higher total micromotion than walking in zone #5 (62 ± 9 vs 51 ± 10 μm, P < .05) and zone #6 (68 ± 17 vs 37 ± 10 μm, P < .05). In addition, during stair descent, the tray exhibited significantly more tilting (anterior zones: 31 ± 17 vs -16 ± 20 μm, P < .05; posterior zones: -60 ± 8 vs -40 ± 7 μm, P < .05) and more anteroposterior displacement in the anterior zones (-25 ± 3 vs -13 ± 2 μm, P < .05) when compared to walking.

CONCLUSION

The relative motion at the bone-prosthesis interface varied substantially around the periphery of the cementless tray. Under the loading conditions evaluated, the tray primarily underwent a rocking motion in the sagittal plane. Compared with walking, stair descent produced significantly more micromotion, especially in the posterior zones.

Osteochondral Allograft Donor-Host Matching by the Femoral Condyle Radius of Curvature

BACKGROUND

Conventional osteochondral allograft (OCA) matching, requiring orthotopic, size-matched condyles, and narrow surgical time windows often prohibit timely transplantation.

HYPOTHESIS

The femoral condyle radius of curvature (RoC) is an appropriate, isolated criterion for donor-host matching in fresh OCAs, potentially enhancing matching efficiency when compared with conventional matching techniques.

STUDY DESIGN

Descriptive laboratory study.

METHODS

In part 1 of this study, 3-dimensional digital reconstructions of 14 randomly selected, cadaveric distal femoral hemicondyles were performed. Each condyle was divided into anterior, middle, and posterior zones. A virtual best-fit grid was applied to each, and each zone's sagittal- and coronal-plane RoCs were determined. Seven nonorthotopic OCA transplantations were performed based on RoC matching with 1-mm tolerance, and the preoperative and postoperative surface geometry were quantified to assess the accuracy of articular surface restoration. Of note, each donor-host pair did not match by the conventional method. In part 2 of this study, 12 cadaveric distal femora were categorized by size and digitized in the aforementioned manner. Simulated circular defects measuring 20, 25, and 30 mm in diameter were introduced into each zone. OCA matches were determined based on donor and host RoCs, and the total number of potential matches (of 71 total comparisons) was recorded as a percentage for each simulated defect. Finally, the results of RoC matching were compared with the conventional method for simulated defects in all zones of both the medial and lateral femoral condyles.

RESULTS

Part 1: The mean surface deviation after OCA transplantation was -0.09 mm, with a mean maximum protrusion at any point of 0.59 mm. Part 2: Using the RoC, 20-mm defects had a 100% chance of being matched. Defects of 25 and 30 mm had a 91% and 64% chance of being matched, respectively. Compared with the conventional method, the RoC method yielded a 3.2-fold greater match rate for lesions of the medial and lateral femoral condyles ( P = .02).

CONCLUSION

This investigation shows that femoral condyle RoCs in the sagittal and coronal planes may be useful, alternative matching criteria, expanding on current standards.

CLINICAL RELEVANCE

These matching criteria may increase the number of available matches, reduce wait times for patients, and reduce the number of wasted grafts.

Comparison of Kinematics and Tibiofemoral Contact Pressures for Native and Transplanted Lateral Menisci

BACKGROUND

Lateral meniscus transplantation is a proven treatment option for the meniscus-deficient knee, yet little is known about meniscal kinematics, strain, and tibiofemoral contact pressure changes after transplantation or the effect of altered root position in lateral meniscus transplantation.

PURPOSE

To compare the native lateral meniscal kinematics, strain, and tibiofemoral contact pressures to a best-case scenario meniscus transplant with perfectly matched size and position and to determine how sensitive these factors are to subtle changes in shape and position by using a nonanatomic meniscus transplant position.

STUDY DESIGN

Controlled laboratory study.

METHODS

The lateral menisci of 8 cadaveric knees were circumferentially implanted with radiopaque spherical markers. They were mounted to a testing apparatus applying muscle and ground-reaction forces. The meniscus was evaluated at 0°, 30°, 90°, and 115° of knee flexion using Roentgen stereophotogrammetric analysis (RSA), with a pressure sensor affixed to the lateral tibial plateau. Measurements were recorded for 3 states: the native lateral meniscus, an anatomic autograft transplant, and a nonanatomic autograft transplant with an anteriorized posterior root position.

RESULTS

After transplantation, there was less posterior displacement in both the anatomic and nonanatomic transplant states compared with the native meniscus, but this was not significant. The largest lateral translation in the native state was 2.38 ± 1.58 mm at the anterolateral region from 0° to 90°, which was increased to 3.28 ± 1.39 mm (P = .25) and 3.12 ± 1.18 mm (P = .30) in the anatomic and nonanatomic transplant states, respectively. Internal deformations of the transplant states were more constrained, suggesting less compliance. The native meniscus distributed load over 223 mm², while both the anatomic (160 mm²) and nonanatomic (102 mm²) states concentrated pressure anteriorly to the tibial plateau centroid.

CONCLUSION

This study is the first to characterize kinematics in the native lateral meniscus compared with a transplanted state utilizing RSA. Results demonstrate increased meniscal constraint and pressure concentrations even after an ideal size and position matched transplantation, which further increased with a nonanatomic posterior root position.

CLINICAL RELEVANCE

The results show that kinematics are similar in both transplanted states when compared with the native meniscus at various flexion angles. Because both transplanted states were more constrained with less deformation compared with the native state, this should allow for relatively safe postoperative range of motion. However, in the transplanted states, peak pressures were distributed over a smaller area and shifted anteriorly. This pattern was exacerbated in the nonanatomic state compared with anatomic. This could have detrimental effects with regard to articular cartilage degeneration, and ultimately result in a failed transplantation.

Does simulated walking cause gapping of meniscal repairs?

BACKGROUND

The objective of rehabilitation following meniscal repair is to promote healing by limiting stresses on repairs, while simultaneously preserving muscle strength and joint motion. Both protective protocols limiting weight bearing and accelerated which do not, have shown clinical success. This study assesses the effects of physiologic gait loading on the kinematic behavior of a repaired medial meniscus.

METHODS

The medial menisci of eight fresh cadaveric knees were implanted with arrays of six 0.8-1.0 mm beads. Pneumatic actuators delivered muscle loads and forces on the knee as each specimen was subjected to a simulated stance phase of gait. Meniscus motion was measured at loading response, mid stance, and toe-off positions. Measurements were performed using biplanar radiography and RSA, with each knee: (a) intact, (b) with posterior longitudinal tear, and (c) after inside-out repair.

RESULTS

The tissue spanning the site of the longitudinal tear underwent compression rather than gapping open in all states (intact [I], torn [T] and repaired [R] states). Average compression at three sites along the posterior half of the meniscus was: posterior horn -0.20 ± 0.08 mm [I], -0.39 ± 0.10 mm [T], and -0.20 ± 0.06 mm [R] (p = 0.15); junction of posterior horn and body -0.11 ± 0.12 mm [I], -0.21 ± 12 mm [T], -0.17 ± 0.09 mm [R] (p = 0.87); and adjacent to the medial collateral ligament -0.07 ± 0.06 mm [I], -0.29 ± 0.13 mm [T], -0.07 ± 0.17 mm [R] (p = 0.35). The entire meniscus translated posteriorly from mid-stance to toe off. Displacement was greatest in the torn state compared to intact, but was not restored to normal levels after repair.

CONCLUSION

The edges of a repaired longitudinal medial meniscal tear undergo compression, not gapping, during simulated gait.

What Is the Optimal Minimum Penetration Depth for "All-Inside" Meniscal Repairs?

PURPOSE

To identify desired minimum depth setting for safe, effective placement of the all-inside meniscal suture anchors.

METHODS

Using 16 cadaveric knees and standard arthroscopic techniques, 3-dimensional surfaces of the meniscocapsular junction and posterior capsule were digitized. Using standard anteromedial and anterolateral portals, the distance from the meniscocapsular junction to the posterior capsule outer wall was measured for 3 locations along the posterior half of medial and lateral menisci. Multiple all-inside meniscal repairs were performed on 7 knees to determine an alternate measure of capsular thickness (X2) and compared with the digitized results.

RESULTS

In the digitized group, the distance (X1) from the capsular junction to the posterior capsular wall was averaged in both menisci for 3 regions using anteromedial and anterolateral portals. Mean distances of 6.4 to 8.8 mm were found for the lateral meniscus and 6.5 to 9.1 mm for the medial meniscus. The actual penetration depth was determined in the repair group and labeled X2. It showed a similar pattern to the variation seen in X1 by region, although it exceeded predicted distances an average 1.7 mm in the medial and 1.5 mm in the lateral meniscus owing to visible deformation of the capsule as it pierced.

CONCLUSIONS

Capsular thickness during arthroscopic repair measures approximately 6 to 9 mm (X1), with 1.5 to 2 mm additional depth needed to ensure penetration rather than bulging of the posterior capsule (X2), resulting in 8 to 10 mm minimum penetration depth range. Surgeons can add desired distance away from the meniscocapsular junction (L) at device implantation, finding optimal minimal setting for penetration depth (X2 + L), which for most repairable tears may be as short as 8 mm and not likely to be greater than 16 mm.

CLINICAL RELEVANCE

Minimum depth setting for optimal placement of all-inside meniscal suture anchors when performing all-inside repair of the medial or lateral meniscus reduces risk of harming adjacent structures secondary to overpenetration and underpenetration of the posterior capsule.

Femoroacetabular impingement negates the acetabular labral seal during pivoting maneuvers but not gait

BACKGROUND

Experimental disruption of the labrum has been shown to compromise its sealing function and alter cartilage lubrication. However, it is not known whether pathological changes to the labrum secondary to femoroacetabular impingement (FAI) have a similar impact on labral function.

QUESTIONS/PURPOSES

Does damage to the labrum occurring in association with abnormal femoral morphology affect the labral seal?

METHODS

Using 10 fresh cadaveric specimens (mean age 50 years, ±8), we measured the capacity of the central compartment of the hip (the iliofemoral joint) to maintain a seal during fluid infusion, which may help elucidate the function of the labrum during weightbearing. Specimens with and without abnormal femoral morphology (six normal-appearing specimens and four whose geometry suggested cam-type FAI) were tested in postures observed during functional activities, including simulations of normal gait, stooping, and pivoting. Each specimen with FAI morphology exhibited secondary damage of the labrum and the adjacent chondral surface, whereas specimens of normal morphology were undamaged.

RESULTS

Average peak central compartment pressure was reduced during pivoting for specimens with the presence of labral damage secondary to FAI. When placed in pivoting positions, hips with FAI maintained lower fluid pressures within the central compartment compared with intact specimens (15±3 versus 42±8 kPa, respectively; effect size: 1.08 [-0.36 to 2.31]; p=0.007). No differences in peak pressure were observed between groups (FAI versus normal) for postures simulating either gait (21±6 versus 22±4 kPa; p=0.902) or stooping (9±2 versus 8±3 kPa; p=0.775) with the numbers available.

CONCLUSIONS

The acetabular seal, quantified by the maximum intraarticular pressure, was reduced during pivoting; however, the seal was maintained during simulated gait and stooping.

CLINICAL RELEVANCE

Because degeneration is progressive with repetitive impingement, loss of the labral seal starts to be seen during pivoting and may progress from there, but in this small-sample cadaver study that evaluated specimens in middle adulthood, the seal remains intact during simulated gait and stooping. Our study suggests that labral damage secondary to cam-type FAI may reduce the ability of the labral to provide an adequate seal of the central compartment of the hip during loading; however, the extent to which this is affected requires further investigation.

The acetabular labrum regulates fluid circulation of the hip joint during functional activities

BACKGROUND

An assessment of the effect of surgical repair or reconstruction on the function of the hip labrum is critical to the advancement of hip preservation surgery; however, validated models of the hip that allow the quantification of labral function in functional joint positions have yet to be developed.

PURPOSE

To evaluate (1) whether intra-articular pressures within the hip are regulated by fluid transport between the labrum and femoral head and (2) whether the sealing capacity of the labrum varies with joint posture.

STUDY DESIGN

Descriptive laboratory study.

METHODS

The sealing ability of the hip labrum was measured during fluid infusion into the central compartments of 8 cadaveric specimens. Additionally, the pathway of fluid transfer from the central to the peripheral compartment was assessed via direct visualization in 3 specimens. The effect of joint posture on the sealing capacity of the labrum was determined by placing all 8 specimens in 10 functional postures. The relationship between pressure resistance and 3-dimensional motion of the femoral head within the acetabulum was quantified using motion analysis and computer modeling.

RESULTS

Resistance to fluid transport from the central compartment of the hip was directly controlled by the labrum during loading. Maximum pressure resistance was affected by joint posture (P = .001). Specifically, positions that increased external rotation of the joint (pivoting) provided an improved seal, while positions that increased flexion combined with internal rotation (stooping) augmented the ease of fluid transport from the central to the peripheral compartment. Maximum pressure resistance was associated with the distance between the labrum and femoral head during pivoting.

CONCLUSION

This study demonstrated that the transfer of fluid from the central compartment of the hip occurs at the junction of the labrum and femoral head. Joint position was shown to strongly affect the sealing function of the labrum and was attributable to the distance between the labrum and femoral head in certain positions.

CLINICAL RELEVANCE

Altering the relationship between the labrum and femoral head may disrupt the sealing ability of the labrum, potentially leaving the joint at risk for pathological changes with time.

Does high knee flexion cause separation of meniscal repairs?

BACKGROUND

Previous clinical studies comparing nonrestrictive and restrictive protocols after meniscal repair have shown no difference in outcomes; however, some surgeons still limit range of motion out of concern that it will place undue stress on the repair.

HYPOTHESIS

Large acute medial meniscal tears will gap during simulated open chain exercises at high flexion angles, and a repaired construct with vertical mattress sutures will not gap.

STUDY DESIGN

Controlled laboratory study.

METHODS

Tantalum beads were implanted in the medial menisci of 6 fresh-frozen cadaveric knees via an open posteromedial approach. Each knee underwent 10 simulated open chain flexion cycles with loading of the quadriceps and hamstrings. Testing was performed on 3 different states of the meniscus: intact, torn, and repaired. Biplanar radiographs were taken of the loaded knee in 90°, 110°, and 135° of flexion for each state. A 2.5-cm tear was created in the posteromedial meniscus and repaired with inside-out vertical mattress sutures. Displacement of pairs of beads spanning the tear was measured in all planes by use of radiostereometric analysis (RSA) with an accuracy of better than 80 μm.

RESULTS

With a longitudinal tear, compression rather than gapping occurred in all 3 regions of the posterior horn of the meniscus (mean ± standard deviation for medial collateral ligament [MCL], -321 ± 320 μm; midposterior, -487 ± 256 μm; root, -318 ± 150 μm) with knee flexion. After repair, meniscal displacement returned part way to intact values in both the MCL (+55 ± 250 μm) and root region (-170 ± 123 μm) but not the midposterior region, where further compression was seen (-661 ± 278 μm).

CONCLUSIONS

Acute posteromedial meniscal tears and repairs with vertical mattress sutures do not gap, but rather compress in the transverse plane at higher flexion angles when subjected to physiologic loads consistent with active, open kinetic chain range of motion rehabilitation exercises. The kinematics of the repaired meniscus more closely resemble that of the intact meniscus than that of the torn meniscus in regions adjacent to the MCL and the root but not in the midposterior region, where meniscal repair led to increased compression across the tear plane.

CLINICAL RELEVANCE

This study supports the idea that nonrestrictive unresisted open chain range of motion protocols do not place undue stress on meniscal repairs.

A phase I trial of isolated hepatic perfusion (IHP) using 5-FU and oxaliplatin in patients with unresectable isolated liver metastases from colorectal cancer

BACKGROUND

Isolated hepatic perfusion (IHP) with melphalan is an established approach for patients with unresectable metastatic liver lesions. This study determined the safety and maximum tolerated dose (MTD) of 5-FU with oxaliplatin via IHP.

METHODS

Standard 3 × 3 Phase I design. Subjects with unresectable isolated CRC liver metastases scheduled for HAI pump were eligible. IHP used fixed-dose oxaliplatin with escalating 5-FU doses. Toxicity (CTCAE v 4.0) and response (RECIST), progression-free survival, and overall survival (OS) were assessed. Systemic and IHP plasma PK of 5-FU, anabolites, and platinum were determined.

RESULTS

All 12 patients had received ≥ 1 line of pre-IHP chemotherapy. There were 4 grade 3 serious adverse events (33.3 %) and 1 grade 4 event (8.3 %). Also, 2 dose-limiting toxicities occurred at DL2 at 300 mg/m(2), resulting in expansion of DL1 at 200 mg/m(2) 5-FU, the eventual MTD. At 6-month follow-up, 9 patients (82 %) demonstrated partial response, while 2 (18 %) exhibited stable disease. Also, 64 % of patients demonstrated a >50 % decrease in CEA. The 1- and 2-year OS probabilities were 90.9 and 71.6 %, respectively, with median follow-up of 24 months. IHP exposures (AUC0-60 min) were 10.9 ± 4.5 μgPt h/mL, 49.3 ± 30.7 μg h/mL 5-FU (DL1), and 70.5 ± 35.5 μg h/mL 5-FU (DL2). Systemic exposure (AUC0-inf) relative to IHP exposure was negligible for both platinum (1.1 ± 1.5 %) and 5-FU (0.09 ± 0.10 %).

CONCLUSIONS

The MTD for IHP was 200 mg/m(2) 5-FU with 40 mg/m(2) oxaliplatin. Systemic exposure to the agents was minimal during IHP. The response and survival observed warrants assessment in a larger phase II trial.

A novel method for the reproducible production of thoracolumbar burst fractures in human cadaveric specimens

BACKGROUND CONTEXT

Currently, there is no reproducible method that produces thoracolumbar burst fractures in human cadavers wherein the fracture configuration mirrors that seen naturally, and soft tissues are maintained.

PURPOSE

To describe a novel method of burst fracture production.

STUDY DESIGN

Biomechanical.

METHODS

Five cadaveric specimens were potted in polymethymethacrylate at T10 and L4; T10 to T12 and L2 to L4 were encased in a pourable rigid foam; flexion of 15° was created focused at L1; and a drop tower weight of 25 kg via "free fall" was used. On load delivery, the spine was allowed to flex without restriction (native bony and soft-tissue constraints). X-ray, computed tomography scan, and open dissection were used to confirm burst configuration.

RESULTS

All five specimens were found to have the "classic" burst configuration characterized by superior end plate comminution, depression of the anterior column, middle column burst with three to five fragments; the classic central fragment retropulsed into the canal, and the pedicular spread via basilar fracture.

CONCLUSION

This novel method affords true burst fracture reproduction without "prestressing" (notching, osteotomies, laminectomy, stripping) used in previous methods. This should allow greater accuracy for the translation of biomechanical testing to clinical applications.

Laparoscopic hiatal hernia repair in patients with poor esophageal motility or paraesophageal herniation

Laparoscopic repair for gastroesophageal reflux disease is now an accepted therapy. However, controversy exists with regard to the choice of operation between complete 360-degree Nissen fundoplication versus partial 270-degree Toupe fundoplication. In addition there is some controversy with regard to the proper choice of operation in patients with poor esophageal motility. Another class of hiatal hernia patients are those patients with paraesophageal herniation. Questions regarding the approach to these patients include whether or not to use a reflux procedure at the time of repair and the role of mesh in repair of these large hernias. This retrospective study was undertaken to compare the results of laparoscopic Nissen fundoplication and Toupe fundoplication in patients with both normal and abnormal esophageal motility. In addition the subset of patients with paraesophageal herniation was studied in an effort to ascertain the best surgical approach in these patients. In this study a retrospective analysis was performed on 188 consecutive patients during the period 1995 to 2001. All patients who presented with hiatal hernia surgical problems during this period were included. Endoscopy was performed in all patients with esophageal reflux. Manometry was performed in all patients except those presenting as emergency incarcerations. pH probe testing was performed in those patients in whom it was deemed necessary to establish the diagnosis. Upper gastrointestinal radiographs were used to define anatomy in paraesophageal hernia patients when possible. All patients with esophageal reflux were first treated with a trial of medical therapy. Patients with esophageal reflux and normal esophageal motility underwent 360-degree Nissen fundoplication. Those patients with poor esophageal motility (less than 65 mm of mercury) underwent laparoscopic 270-degree Toupe fundoplication. Patients presenting with paraesophageal herniation underwent laparoscopic repair. When possible esophageal manometry was performed on these patients preoperatively and if normal peristalsis was documented a Nissen fundoplication was performed. If poor esophageal motility was documented before surgery a Toupe fundoplication was performed. Mesh reinforcement of the diaphragmatic hiatus was used if necessary to complete a repair without tension. Patients were followed both by their primary gastroenterologist and their surgeon. Follow-up studies including endoscopy, pH probe, and upper gastrointestinal series were used as necessary in the postoperative period to document any problems as they occurred. Of the 188 patients in the study 141 patients underwent Nissen fundoplication, 21 patients underwent Nissen fundoplication and repair of paraesophageal hernia, 15 underwent Toupe fundoplication, seven underwent Toupe and paraesophageal hernia repair, and four paraesophageal hernia repair alone. One hundred eighty-three patients underwent a laparoscopic operation. Five patients of the 188 underwent an initial open operation-two of these patients because of the size of their paraesophageal hernia. Three of these patients had reoperations of remote operations done years before at other institutions. Twenty-two patients with poor esophageal motility (11.7 %) were included in the study. Fifteen patients required Toupe fundoplication whereas seven patients required Toupe fundoplication and repair of paraesophageal hernias. Mesh repair of paraesophageal hernias was accomplished in ten patients. Patients undergoing Toupe fundoplication had a 13 per cent dysphagia rate less than 4 weeks postoperatively and a 0% dysphagia rate greater than four weeks postoperatively. Patients undergoing Nissen fundoplication had a 16 per cent dysphagia rate less than 4 weeks postoperatively, 2 per cent dysphagia rate greater than 4 weeks postoperatively and no dysphagia at 6 weeks postoperatively. Recurrent symptomatic reflux occurred in 1.4 per cent of Nissen fundoplications and 6.7 per cent of Toupe fundoplications. Of Nissen and paraesophageal repairs 14.2 per cent had reflux and 14.3 per cent of Toupe and paraesophageal repairs had recurrent symptomatic reflux. Overall, complication rate was low. Use of mesh to repair large paraesophageal hernias resulted in a recurrence rate of 0 per cent. There was no instance of infection or bowel fistulization related to the use of mesh. We conclude that laparoscopic Nissen fundoplication in patients with normal esophageal motility is associated with a low rate of dysphagia and a low rate of recurrent reflux. Toupe fundoplication when used in reflux patients with poor esophageal motility is associated with a low rate of dysphagia and an acceptable rate of recurrent reflux. Laparoscop

Induction of tyrosinase gene transcription in human iris organ cultures exposed to latanoprost

OBJECTIVE

Topical administration of latanoprost sometimes induces gradual iris darkening. The present study was undertaken to determine if latanoprost can increase transcription of the gene for tyrosinase, an important enzyme in the biosynthesis of melanin. Results from brown, hazel, and blue irides were compared.

METHODS

Iris tissue was isolated from 30 pairs of postmortem human donor eyes, and 2 iris segments from each eye were incubated in tissue culture medium supplemented with 200nM latanoprost acid or vehicle for 7 days. Tyrosinase messenger RNA (mRNA) was determined using real-time polymerase chain reaction analysis (TaqMan quantitative polymerase chain reaction). Results for tyrosinase mRNA were normalized according to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA in each sample.

RESULTS

Tyrosinase mRNA expression was similar in blue and hazel irides, and ranged from 0.7-fold to 12.6-fold greater than GAPDH expression. In contrast, control brown iris culture tyrosinase expression ranged from 6.4-fold to 265-fold greater than GAPDH expression. Induction of tyrosinase mRNA by latanoprost was below threshold in all the blue iris cultures (n = 8 pairs), present in 1 of 9 hazel iris cultures, and present in 5 of 13 brown iris cultures. Mean induction in the responding hazel iris cultures was 1.40-fold. Mean induction among the responding brown iris cultures was 2.97-fold.

CONCLUSIONS

These observations support the view that iris darkening associated with latanoprost treatment reflects induction of tyrosinase expression. Moreover, they suggest that the probability that latanoprost will increase tyrosinase expression is directly related to the magnitude of tyrosinase expression before treatments are initiated.

CLINICAL RELEVANCE

The variability of iris darkening with latanoprost may reflect natural variation in the basal transcription of tyrosinase.

Second stage of a genome scan of schizophrenia: study of five positive regions in an expanded sample

In a previous genome scan of 43 schizophrenia pedigrees, nonparametric linkage (NPL) scores with empirically derived pointwise P-values less than 0.01 were observed in two regions (chromosomes 2q12-13 and 10q23) and less than 0.05 in three regions (4q22-23, 9q22, and 11q21). Markers with a mean spacing of about 5 cM were typed in these regions in an expanded sample of 71 pedigrees, and NPL analyses carried out. No region produced significant genomewide evidence for linkage. On chromosome 10q, the empirical P-value remained at less than 0.01 for the entire sample (D10S168), evidence in the original 43 pedigrees was slightly increased, and a broad peak of positive results was observed. P-values less than 0.05 were observed on chromosomes 2q (D2S436) and 4q (D4S2623), but not on chromosomes 9q or 11q. It is concluded that this sample is most supportive of linkage on chromosome 10q, with less consistent support on chromosomes 2q and 4q. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:864-869, 2000.

Laparoscopic repair of bilateral inguinal hernias in a patient with müllerian agenesis

OBJECTIVE

To report a case of laparoscopic repair of bilateral inguinal hernias in a patient with müllerian agenesis.

DESIGN

Case report.

SETTING

Hospital.

PATIENT(S)

An 18-year-old woman with müllerian agenesis who presented with symptomatic inguinal hernias containing ovaries.

INTERVENTION(S)

Laparoscopic repair of bilateral inguinal hernias.

MAIN OUTCOME MEASURE(S)

Hernia repair was accomplished laparoscopically.

RESULT(S)

Outpatient laparoscopic repair of bilateral inguinal hernias with reduction of ovaries was performed using an extraperitoneal approach without complication.

CONCLUSION(S)

Laparoscopic approach of inguinal hernias can be an option for surgical repair in patients with müllerian agenesis even when the hernias contain ovaries.

Genome scan of schizophrenia

OBJECTIVE

The goal of this study was to identify chromosomal regions likely to contain schizophrenia susceptibility genes.

METHOD

A genomewide map of 310 microsatellite DNA markers with average spacing of 11 centimorgans was genotyped in 269 individuals--126 of them with schizophrenia-related psychoses--from 43 pedigrees. Nonparametric linkage analysis was used to assess the pattern of allele sharing at each marker locus relative to the presence of disease.

RESULTS

Nonparametric linkage scores did not reach a genomewide level of statistical significance for any marker. There were five chromosomal regions in which empirically derived p values reached nominal levels of significance at eight marker locations. There were p values less than 0.01 at chromosomes 2q (with the peak value in this region at D2S410) and 10q (D10S1239), and there were p values less than 0.05 at chromosomes 4q (D4S2623), 9q (D9S257), and 11q (D11S2002).

CONCLUSIONS

The results do not support the hypothesis that a single gene causes a large increase in the risk of schizophrenia. The sample (like most others being studied for psychiatric disorders) has limited power to detect genes of small effect or those that are determinants of risk in a small proportion of families. All of the most positive results could be due to chance, or some could reflect weak linkage (genes of small effect). Multicenter studies may be useful in the effort to identify chromosomal regions most likely to contain schizophrenia susceptibility genes.

Polyclonal Ki-67 expression in transitional cell carcinoma of the bladder

The proliferation kinetics of 101 cases of transitional cell carcinoma (TCC) and seven cases of transitional cell carcinoma-in-situ of the bladder were assessed following staining with polyclonal Ki-67 antibody (pKi-67). Labeling indices ranged from 49% to 60.2% with a mean value of 22.2% for all cases. A significant association between pKi-67 indices, tumor grade and tumor stage was observed, with significant differences between pKi-67 indices of Grade 1 and 3 tumors and Grade 2 and 3 tumors. Significant differences in labeling indices were also found between superficial (Ta) tumors and both musculoinvasive (T2/T3a) tumors and those infiltrating the perivesical fat (T3b). pKi-67 indices for carcinoma-in-situ were similar to those noted for Grade 1 TCC. No difference in pKi-67 index was found when tumors were classified according to the morphology of the tumor invasion front. It is concluded that pKi-67 index is a useful marker for tumor progression for vesical TCC and that this immunohistochemical stain may assist clinical assessment of the potential behaviour of tumors in individual cases.

Luminal epithelial antigen (LEA.135) expression correlates with tumor progression for transitional carcinoma of the bladder

Luminal epithelial antigen (LEA.135) expression has been shown to have prognostic significance in breast carcinoma, however its relationship to tumor progression in other forms of malignancy is unknown. This study evaluates LEA.135 expression in bladder transitional cell carcinoma (TCC) and compares the findings with tumor stage and grade, and polyclonal Ki-67 derived cell cycle activity. LEA.135 expression was evaluated by immunohistochemical staining using the streptavidin-biotin method. Staining distribution was graded 0 to 4 and the results were compared with World Health Organisation tumor grade, UICC TNM stage and fraction of actively cycling cells showing positive pKi-67 immunohistochemical staining. In normal bladder epithelium, LEA.135 staining was confined to the luminal surface of superficial epithelium. In lower grade, superficial TCC LEA.135 overexpression was noted and there was a progressive loss of expression in tumors of higher grade (p = 0.0001) and advanced stage (p = 0.0001). No LEA.135 staining was seen in carcinoma-in-situ. Loss of LEA.135 expression correlates with tumor progression for bladder TCC.

Multiple pancreatic abscesses due to Candida albicans following ERCP

A report is presented of a patient who developed multiple abscesses of the pancreas due to Candida albicans following an Endoscopic retrograde chole-pancreatography (ERCP) for acute pancreatitis. He was not immunocompromised, debilitated and had not had recent surgery. There was complete radiological and clinical resolution of the abscess on prolonged treatment with amphotericin alone. Only a few cases of candidal abscess of the pancreas have been reported, none of them having occurred after an ERCP.

Latex allergy in patients with spina bifida

Latex recently has been associated with severe intraoperative IgE-mediated anaphylactic reactions. Pediatric patients with meningomyelocele (spina bifida) appear to be specifically at risk for this type of reaction. This article provides background information on the etiology of latex allergies, identifies some commonly used dental products containing latex, recommends some alternatives to use, and suggests precautions the dental practitioner should take when treating high-risk individuals such as spina bifida patients.

Massive hepatic necrosis in toxemia of pregnancy

Hepatic rupture and infarction associated with toxemia of pregnancy usually occur in multiparous women close to 30 years of age. The most important presenting symptom is right upper-quadrant abdominal pain. Sonography is the most expedient way of making the diagnosis of either rupture or hemorrhagic necrosis, but computed tomography is more sensitive. Elevated transaminase levels and thrombocytopenia or disseminated intravascular coagulation may occur acutely but resolve quickly. Termination of pregnancy is the cornerstone of any treatment plan. Many cases may not require operative treatment other than inspection. In others, surgical hemostasis will be lifesaving. We describe four preeclamptic women, two with ruptured subcapsular hematomas and two with hemorrhagic infarction. Radiological and laboratory evidence of liver damage and recovery are presented.

Doramectin, a new avermectin highly efficacious against gastrointestinal nematodes and lungworms of cattle and pigs: two studies carried out under field conditions in Germany

Two field studies were carried out to confirm the efficacy of doramectin in cattle and pigs in Europe. A total of 40 cattle harbouring naturally acquired infections of gastrointestinal nematodes, including Ostertagia spp., Oesophagostomum spp., Cooperia spp., Haemonchus spp., Nematodirus spp. and Trichuris spp., were allocated to a treated or a control group (20 animals/group), and 100 harbouring naturally acquired infections of gastrointestinal nematodes and lungworms, including Oesophagostomum spp., Metastrongylus spp., Ascaris suum and Trichuris suis, were allocated to either a treated (60 pigs) or a control (40 pigs) group. Animals in the treated groups received an injection of doramectin at 200 micrograms/kg (1 ml/50 kg) for cattle or 300 micrograms/kg (1 ml/33 kg) for swine. Animals in the control groups received saline at 1 ml/50 kg for cattle or 1 ml/33 kg for swine. The cattle were injected by the subcutaneous route in the lateral mid-line of the neck and the pigs were injected intramuscularly in the neck. Faecal egg counts were determined for all animals on days--7, 0, 7, 14 and 21 of the studies, where day 0 was the day of treatment. The mean daily weight gain of doramectin-treated animals was significantly higher than that of the control animals over the 21 days of the studies (P < 0.0007 for cattle and P = 0.0001 for swine). At 21 days after treatment, the mean faecal egg counts of the doramectin-treated animals were significantly lower than those of the control animals and were reduced by 100% as compared with pretreatment levels. No adverse reaction to treatment was observed in any animal during either study.(ABSTRACT TRUNCATED AT 250 WORDS)

Association between primary dentition wear and clinical temporomandibular dysfunction signs

Dental wear facets often are considered indicators of temporomandibular dysfunction (TMD). Dental wear facets are common in children, but their association with TMD signs is unknown. A reproducible, clinical evaluation of TMD signs for young children shows no statistically significant association between primary dentition wear facets and clinical signs of TMD (P less than or equal to 0.05). Wear facets in young children do not appear to warrant TMD evaluation or treatment.

Incidental finding of an intranasal foreign body discovered on routine dental examination: case report

A nasal foreign body was discovered radiologically on an initial dental examination of a young child. The child was a candidate for dental rehabilitation, using nasotracheal intubation under general anesthesia. The parents were unaware of the object's presence, and the child had no nasal symptoms. The child was referred to the Otolaryngology-Head and Neck Surgery Service to have the object removed; this was accomplished successfully without sequelae on an outpatient basis. Dentists and physicians who treat children should be alert to the possible presence of intranasal objects in their patients.

A quality assessment of the effects of a hydrogenous filter on a p(66)Be(40) neutron beam

Recent measurements in a p(62)Be(36) neutron therapy beam have shown that the quality of the in-phantom beam changes with depth. This variation can be ascribed to the presence of a relatively large low-energy neutron component emanating from the neutron source. As part of the pre-clinical calibration programme at a newly commissioned neutron therapy facility, radiobiological and microdosimetric observations were made to determine the magnitude of this effect on a p(66)Be(40) beam and to evaluate the hardening effect of a hydrogenous filter. The reported data identify a correlation between the two assays and quantify a linear relationship between y* and filter thicknesses less than or equal to 6 cm. Using the data obtained in the study, a filter thickness was selected to comply with clinical requirements. By employing lineal energy spectra, it is demonstrated that subtle changes in beam quality may be quantified in a reproducible manner without resorting to time-consuming radiobiological studies.

Demonstrations

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The Principles of Ionic Medication

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