Molecular mechanism of Ena/VASP-mediated actin-filament elongation.

Ena/VASP proteins are implicated in a variety of fundamental cellular processes including axon guidance and cell migration. In vitro, they enhance elongation of actin filaments, but at rates differing in nearly an order of magnitude according to species, raising questions about the molecular determinants of rate control. Chimeras from fast and slow elongating VASP proteins were generated and their ability to promote actin polymerization and to bind G-actin was assessed. By in vitro TIRF microscopy as well as thermodynamic and kinetic analyses, we show that the velocity of VASP-mediated filament elongation depends on G-actin recruitment by the WASP homology 2 motif. Comparison of the experimentally observed elongation rates with a quantitative mathematical model moreover revealed that Ena/VASP-mediated filament elongation displays a saturation dependence on the actin monomer concentration, implying that Ena/VASP proteins, independent of species, are fully saturated with actin in vivo and generally act as potent filament elongators. Moreover, our data showed that spontaneous addition of monomers does not occur during processive VASP-mediated filament elongation on surfaces, suggesting that most filament formation in cells is actively controlled.

Cervical Myelopathy with Concomitant Guillain-Barré Syndrome: A Case Report.

CASE: We present a case of a 67-year-old female patient with concomitant cervical spondylotic myelopathy (CSM) and Guillain-Barré syndrome (GBS). Surgical intervention, including cervical decompression and arthrodesis, was performed to address cervical myelopathy symptoms. Despite initial improvement, the patient's motor function deteriorated, leading to the diagnosis of GBS. The patient's hospital course was protracted with a complicated recovery. CONCLUSION: This case emphasizes the clinical details of coexisting CSM and GBS, highlighting the importance of diagnosing and considering demyelinating diseases when determining the optimal timeline for surgical intervention. These findings inform decision-making for clinicians encountering similar patient presentations.

Mismatch Between Pelvic Incidence and Lumbar Lordosis After Personalized Interbody Fusion: The Importance of Preoperative Planning and Alignment in Degenerative Spine Diseases.

BACKGROUND: Emerging data have highlighted the significance of planning and aligning total and segmental lumbar lordosis with pelvic morphology when performing short-segment fusion with the goal of reducing the risk of adjacent segment disease while also decreasing spine-related disability. This study evaluates the impact of personalized interbody implants in restoring pelvic incidence-lumbar lordosis (PI-LL) mismatch compared with a similar study using stock interbody implants. METHODS: This multicenter retrospective analysis assessed radiographic pre- and postoperative spinopelvic alignment (PI-LL) in patients who underwent 1- or 2-level lumbar fusions with personalized interbody implants for degenerative (nondeformity) indications. The aim was to assess the incidence of malalignment (PI-LL ≥ 10°) both before and after fusion surgery and to determine the rate of alignment preservation and/or correction in this population. RESULTS: There were 135 patients included in this study. Of 83 patients who were aligned preoperatively, alignment was preserved in 76 (91.6%) and worsened in 7 (8.4%). Among the 52 preoperatively malaligned patients, alignment was restored in 23 (44.2%), and 29 (55.8%) were not fully corrected. Among patients who were preoperatively aligned, there was no statistically significant difference in either the "preserved" or "worsened" groups between stock devices and personalized interbody devices. In contrast, among patients who were preoperatively malaligned, there was a statistically significant increase in the "restored" group (P = 0.046) and a statistically significant decrease in the "worsened" groups in patients with personalized interbodies compared with historical stock device data (P < 0.05). CONCLUSIONS: Compared with a historical cohort with stock implants, personalized interbody implants in short-segment fusions have shown a statistically significant improvement in restoring patients to normative PI-LL. Using 3-dimensional preoperative planning combined with personalized implants provides an important tool for planning and achieving improvement in spinopelvic parameters.

Radiographic Alignment in Deformity Patients Treated With Personalized Interbody Devices: Early Experience From the COMPASS Registry.

BACKGROUND: Literature supports the need for improved techniques to achieve spinopelvic alignment and reduce complication rates in patients with adult spinal deformity (ASD). Personalized interbody devices were developed to address this need and are under evaluation in the multicenter Clinical Outcome Measures in Personalized aprevo (circle R superscript) Spine Surgery (COMPASS (TM suprascript) registry. This report presents interim COMPASS pre- and postoperative sagittal alignment results and complication rates for a subcohort of COMPASS patients diagnosed and surgically treated for spinal deformity. METHODS: COMPASS is a postmarket observational registry of patients enrolled either before or after index surgery and then followed prospectively for 24 months. Sagittal alignment was assessed with SRS-Schwab modifiers for pelvic incidence minus lumbar lordosis, pelvic tilt, and T1 pelvic angle. Summed SRS-Schwab modifiers were utilized to assign overall deformity status as mild, moderate, or severe. Complications were extracted from patient medical records. RESULTS: The study included 67 patients from 9 centers. Preoperative severe deformity was observed in 66% of patients. Index surgeries included implantation of a median of 2 personalized interbody devices by anterior, lateral, or transforaminal approaches and with a median of 8 posteriorly instrumented levels. Overall postoperative sagittal alignment improved with a significant decrease in the mean sum of SRS-Schwab modifiers that correlated strongly to improvements in pelvic incidence minus lumbar lordosis. Among 44 patients with preoperative severe overall deformity, 16 improved to moderate and 9 to mild deformity. Complications occurred for 13 patients (19.4%), including 1 mechanical complication requiring revision 9 months after surgery and none related to personalized interbody devices. CONCLUSIONS: This study demonstrates that ASD patients whose treatment included personalized interbody devices can obtain favorable postoperative alignment status comparable to published results and with no complications related to the personalized interbody devices. CLINICAL RELEVANCE: This study contributes to growing evidence that personalized interbody devices contribute to improved sagittal alignment in ASD patients by directly adjusting the orientation of adjacent vertebra.

Changes in Alignment at Untreated Vertebral Levels Following Short-Segment Fusion Using Personalized Interbody Cages: Leveraging Personalized Medicine to Reduce the Risk of Reoperation.

BACKGROUND: An abnormal postoperative lordosis distribution index (LDI), which quantifies the ratio between the lordosis at L4 to S1 and the lordosis at L1 to S1, contributes to the development of adjacent segment disease and increased revision rates in patients undergoing short-segment lumbar intervertebral fusions. Incorporating preoperative spinopelvic parameters and LDI into the surgical plan for short-segment fusion is important for guiding alignment restoration and preserving normal preoperative alignment in unfused segments. This study examined changes in LDI, segmental lordosis, and lordosis of the unfused levels in patients treated with personalized interbody cage (PIC) implants. METHODS: This retrospective study evaluated radiographic measurements from 111 consecutively treated patients diagnosed with degenerative spinal conditions and treated with a short-segment fusion of L4 to L5, L5 to S1, or L4 to S1 using PIC implant(s) within 6 months of the fusion procedure. Comparisons of intervertebral lordosis for treated and untreated levels as well as LDI pre- and postoperatively were performed. RESULTS: In patients with a preoperative hypolordotic distribution (LDI < 50%), statistically significant increases were found in LDI postoperatively, approaching the normal LDI range (LDI 50%-80%). Likewise, patients with hyperlordotic distribution preoperatively (LDI > 80%) experienced a decrease in LDI postoperatively, trending toward the normal range, although the changes were not statistically significant. Intervertebral lordosis for the L5 to S1 level increased significantly following the placement of a PIC in the normal and hypolordotic LDI groups. Changes in intervertebral lordosis for L5 to S1 were not significant for patients with preoperative hyperlordotic LDI. Reciprocal changes in intervertebral lordosis at L1 to L4 were not observed in any groups. CONCLUSIONS: PIC implants may provide a benefit for patients, particularly those with hypolordotic distributions preoperatively. They have the potential to further improve patient outcomes by helping surgeons to achieve patient-specific lordosis goals, which may help to reduce the risk of adjacent segment disease and revisions in patients undergoing short-segment lumbar intervertebral fusions. CLINICAL RELEVANCE: Personalized implants can help surgeons achieve patient-specific alignment goals, potentially prevent adjacent segment disease, and reduce long-term reinterventions.

Characterization of SiGe films for use as a National Institute of Standards and Technology Microanalysis Reference Material (RM 8905).

Bulk silicon-germanium (SiGe) alloys and two SiGe thick films (4 and 5 microm) on Si wafers were tested with the electron probe microanalyzer (EPMA) using wavelength dispersive spectrometers (WDS) for heterogeneity and composition for use as reference materials needed by the microelectronics industry. One alloy with a nominal composition of Si0.86Ge0.14 and the two thick films with nominal compositions of Si0.90Ge0.10 and Si0.75Ge0.25 on Si, evaluated for micro- and macroheterogeneity, will make good microanalysis reference materials with an overall expanded heterogeneity uncertainty of 1.1% relative or less for Ge. The bulk Ge composition in the Si0.86Ge0.14 alloy was determined to be 30.228% mass fraction Ge with an expanded uncertainty of the mean of 0.195% mass fraction. The thick films were quantified with WDS-EPMA using both the Si0.86Ge0.14 alloy and element wafers as reference materials. The Ge concentration was determined to be 22.80% mass fraction with an expanded uncertainty of the mean of 0.12% mass fraction for the Si0.90Ge0.10 wafer and 43.66% mass fraction for the Si0.75Ge0.25 wafer with an expanded uncertainty of the mean of 0.25% mass fraction. The two thick SiGe films will be issued as National Institute of Standards and Technology Reference Materials (RM 8905).

Farm-scale evaluation of ozonation for mitigating ammonia concentrations in broiler houses.

This study evaluated the effectiveness of in-house ozonation within the public health standard limit (0.1 parts per million [ppm]) for mitigating ammonia (NH3) concentrations inside commercial broiler houses. The project was conducted in four identical tunnel-ventilated houses. Two houses served as treatment and the other two served as control units. The experiment was replicated in five consecutive flocks. Except for ozonation treatment, all other operational parameters including feed, broiler strain, age and number of broilers, and ventilation system were the same among four houses. NH3 and carbon dioxide (CO2) concentrations in the treatment and control houses were measured for a minimum of 48 hr/week throughout the five flocks of 8 or 9 weeks each. The gas measurements were conducted using portable multigas units (PMUs). House temperatures were recorded with data loggers in each flock. Comparison of temperatures and CO2 concentrations among houses indicated no significant differences in ventilation rates among treatment and control houses in any of the five flocks. As a result, comparisons of NH3 concentrations inside houses were used to evaluate the effectiveness of house ozonation for NH3 emission mitigation. Statistical test of mean NH3 concentrations for each flock separated by house indicated that the house-to-house variation was significantly smaller than the flock-to-flock variation. There was a substantial variation in NH3 concentrations across different flocks, but no house had consistently higher or lower mean NH3 concentrations than any other. Evaluations for differences in mean NH3 from week to week, between treatment groups, and differences in week-to-week variations between treatment groups suggested that ozone effect was not uniform for each week and the effect was not statistically significant for any week. Tests of overall ozone treatment effect and treatment-week interaction indicated there was no difference in mean NH3 between the control and ozone treatment groups (P = 0.25), nor was the week effect different for control and treatment groups (P = 0.46). The results of this field evaluation indicate that there was no statistical evidence to suggest that the ozone treatment has any effect on average NH3 concentrations in these chicken houses.

Standardization of the egg hatch test for the detection of benzimidazole resistance in parasitic nematodes.

The ability to reliably detect anthelmintic resistance is a crucial part of resistance management. If data between countries are to be compared, the same test should give the same results in each laboratory. As the egg hatch test for benzimidazole resistance is used for both research and surveys, the ability of different laboratories to obtain similar results was studied through testing of known isolates of cyathostomins, Haemonchus contortus, Ostertagia ostertagi, and Cooperia oncophora in programs supported by the EU (Cost B16 and FP6-PARASOL). Initial results showed difficulties in obtaining reproducible and similar data within and between laboratories. A series of ring tests, i.e., simultaneous and coordinated rounds of testing of nematode isolates in different laboratories was subsequently performed. By adopting identical protocols, especially the use of deionized water and making dilutions of thiabendazole in dimethyl sulfoxide in the final ring test, laboratories correctly identified both susceptible and resistant isolates. The protocols for the test and preparation of solutions of thiabendazole are described.

Manganese-enhanced magnetic resonance microscopy of mineralization.

Paramagnetic manganese (II) can be employed as a calcium surrogate to sensitize magnetic resonance microscopy (MRM) to the processing of calcium during bone formation. At high doses, osteoblasts can take up sufficient quantities of manganese, resulting in marked changes in water proton T(1), T(2) and magnetization transfer ratio values compared to those for untreated cells. Accordingly, inductively coupled plasma mass spectrometry (ICP-MS) results confirm that the manganese content of treated cell pellets was 10-fold higher than that for untreated cell pellets. To establish that manganese is processed like calcium and deposited as bone, calvaria from the skull of embryonic chicks were grown in culture medium supplemented with 1 mM MnCl(2) and 3 mM CaCl(2). A banding pattern of high and low T(2) values, consistent with mineral deposits with high and low levels of manganese, was observed radiating from the calvarial ridge. The results of ICP-MS studies confirm that manganese-treated calvaria take up increasing amounts of manganese with time in culture. Finally, elemental mapping studies with electron probe microanalysis confirmed local variations in the manganese content of bone newly deposited on the calvarial surface. This is the first reported use of manganese-enhanced MRM to study the process whereby calcium is taken up by osteoblasts cells and deposited as bone.

Acute Lumbar Paraspinal Myonecrosis in Football Players with Sickle Cell Trait: A Case Series.

We report six cases of a novel syndrome of acute, exertional low back pain in football players, five in college and one in the National Football League. All six are African Americans with sickle cell trait (SCT). The acute low back pain is severe and can be disabling, and the condition can be confused with muscle strain, discogenic pain, stress fracture, or other problems in athletes. Our evidence shows that this syndrome is caused by lumbar paraspinal myonecrosis (LPSMN), which likely often contributes to the lumbar paraspinal compartment syndrome. We explain why we believe SCT is a risk factor for LPSMN in football conditioning/training, although SCT is not requisite for this syndrome, which has been reported rarely in other sports (e.g., snow or water skiing) and especially in weight lifting that targets lumbar muscles. The clinical course of LPSMN in football can be mild and allow return to play in a week or two, or it can be severe and lead to long-term sequelae. Knowledge of this syndrome will enable athletic trainers and team physicians to diagnose it early, treat it properly, and lessen its effect. Further research will help us learn how better to prevent it.

Surgical management of metastatic spinal neoplasms.

OBJECT: In this study the authors retrospectively review outcomes in patients treated for metastases to the spine. Surgery for metastatic tumors to the spine remains an important part of the treatment armamentarium. Maximum tumor resection with a minimum number of complications is one of the goals of surgery. Current surgical procedures include tumor resection and spinal stabilization for optimal results. METHODS: The records of 96 patients who underwent surgery for a metastatic spine tumor at the authors' institution were reviewed. Spinal instrumentation was used in the majority of patients. Ambulatory status was maintained in 91% and pain improved in 94% of patients. Complications included infection (5.2%), cerebrospinal fluid leak (2%), and delayed hardware failure (3.1%). The mortality rate was 4.1%; the main cause was due to tumor progression. CONCLUSIONS: Surgery is indicated in a select group of patients with metastatic tumors to the spine. A multidisciplinary approach is recommended for patient selection and complication avoidance. Surgical options, including approach, type of reconstruction and extent of resection (including en bloc spondylectomy) need to be addressed for optimal outcomes.

Comparison of circumferential pelvic sheeting versus the T-POD on unstable pelvic injuries: A cadaveric study of stability.

OBJECTIVES: Commercially available binder devices are commonly used in the acute treatment of pelvic fractures, while many advocate simply placing a circumferential sheet for initial stabilization of such injuries. We sought to determine whether or not the T-POD would provide more stability to an unstable pelvic injury as compared to circumferential pelvic sheeting. METHODS: Unstable pelvic injuries (OTA type 61-C-1) were surgically created in five fresh, lightly embalmed whole human cadavers. Electromagnetic sensors were placed on each hemi-pelvis. The amount of angular motion during testing was measured using a Fastrak, three-dimensional, electromagnetic motion analysis device (Polhemus Inc., Colchester, VT). Either a T-POD or circumferential sheet was applied in random order for testing. The measurements recorded in this investigation included maximum displacements for sagittal, coronal, and axial rotation during application of the device, bed transfer, log-rolling, and head of bed elevation. RESULTS: There were no differences in motion of the injured hemi-pelvis during application of either the T-POD or circumferential sheet. During the bed transfer, log-rolling, and head of bed elevation, there were no significant differences in displacements observed when the pelvis was immobilized with either a sheet or pelvic binder (T-POD). CONCLUSIONS: A circumferential pelvic sheet is more readily available, costs less, is more versatile, and is equally as efficacious at immobilizing the unstable pelvis as compared to the T-POD. We advocate the use of circumferential sheeting for temporary stabilization of unstable pelvic injuries.

Does application position of the T-POD affect stability of pelvic fractures?

OBJECTIVE: Most trauma centers place pelvic binders on unstable pelvic fractures for acute management and control of hemorrhage. It has been proposed that the binders be placed at the level of the greater trochanters of the femur. Our hypothesis was that application of the T-POD at this site would provide better immobilization of an unstable pelvic injury than a more cephalad location. METHODS: Unstable pelvic injuries (OTA type 61-C1) were surgically created in 9 fresh whole human cadavers. Electromagnetic sensors were affixed to the intact and injured sides of the pelvis. A Fastrak, three-dimensional electromagnetic motion analysis device was used to determine the angular motion occurring at the fractured sites. Maximum displacements for sagittal, coronal, and axial rotation were recorded during application of the binder, while performing bed transfers, while logrolling, and elevating the head of the bed. The T-POD device was placed either over the greater trochanters or at the level of the anterior superior iliac spine as per manufacturer's recommendations. RESULTS: There were no significant differences in the amount of motion produced during application of the T-POD at either location. There was less motion observed in all planes of motion during all maneuvers when the T-POD was placed at the level of the greater trochanters versus anterior superior iliac spine. During bed transfers, this was statistically significant in all planes. This was statistically significant while logrolling in the axial plane and the coronal plane during head of bed elevation. CONCLUSIONS: We advocate the placement of pelvic binder devices at the level of the greater trochanters for improved control of the fracture in an unstable pelvic injury. This may result in improved control of hemorrhage, better access to the abdomen, and greater patient comfort.

Stabilization of 2-column thoracolumbar fractures with orthoses: a cadaver model.

STUDY DESIGN: A gross anatomic and motion analysis study in cadavers. OBJECTIVE: Assess spinal motion in a cadaveric spinal fracture model and investigate the ability of external orthoses to control this motion. SUMMARY OF BACKGROUND DATA: External orthoses are frequently prescribed for patients who have experienced burst fracture of the thoracolumbar spine. Despite the substantial expense involved, there is little data confirming their value. METHODS: A T12 burst fracture model was created in 5 lightly embalmed cadavers by resecting the anterior and middle columns of the T12 vertebra through a thoracolumbar anterior approach to the spine. An electromagnetic motion tracking and analysis system was used to track angular and linear displacement at the fracture during routine patient maneuvers. Several commonly used orthoses, including an extension brace and both an "off-the-shelf" and custom-molded thoracic-lumbar-sacral orthosis (TLSO), were applied to the cadavers and the affect on fracture site motion was assessed. RESULTS: Application of all 3 styles of brace resulted in angular motion of 8° to 12° in flexion-extension, 11° to 20° in axial rotation, and 8° to 10° of lateral bending. Brace application resulted in linear displacement of 29 to 46 mm in the medial-lateral plane, 21 to 23 mm in the axial plane, and 21 to 37 mm in the anterior-posterior plane. During logrolling maneuvers, TLSO style braces diminished angular motion, although residual motion in the range of 5° remained. TLSO style braces had little effect on linear translation. When placed in a seated position in bed, TLSO style braces diminished flexion and extension modestly, but did not influence lateral bending or linear translation. Extension style braces had no effect on fracture motion during any activity tested. CONCLUSION: In a cadaver model of a burst fracture, there is surprising angular and linear motion at the fracture during common hospital activities. TLSO orthoses can decrease angular motion but do not effect translation at the fracture. An extension orthosis had no effect on motion at the spinal fracture site.

Total motion generated in the unstable cervical spine during management of the typical trauma patient: a comparison of methods in a cadaver model.

STUDY DESIGN: Biomechanical cadaveric study. OBJECTIVE: We sought to analyze the amount of motion generated in the unstable cervical spine during various maneuvers and transfers that a trauma patient would typically be subjected to prior to definitive fixation, using 2 different protocols. SUMMARY OF BACKGROUND DATA: From the time of injury until the spine is adequately stabilized in the operating room, every step in management of the spine-injured patient can result in secondary injury to the spinal cord. METHODS: The amount of angular motion between C5 and C6, after a surgically created unstable injury, was measured using an electromagnetic motion analysis device (Polhemus Inc., Colchester, VT). A total sequence of maneuvers and transfers was then performed that a patient would be expected to go through from the time of injury until surgical fixation. This included spine board placement and removal, bed transfers, lateral therapy, and turning the patient prone onto the operating table. During each of these, we performed what has been shown to be the best and commonly used (log-roll) techniques. RESULTS: During bed transfers and the turn prone for surgery, there was statistically more angular motion in each plane for traditional transfer with the spine board and manually turning the patient prone as commonly done (P < 0.01). During spine board placement, there was more motion in all 3 planes with log-rolling, and this reached statistical significance for axial rotation (P = 0.015) and lateral bending (P = 0.004). There was more motion during board removal with log-rolling in all 3 planes. This was statistically significant for lateral bending (P = 0.009) and approached significance in flexion-extension (P = 0.058) and axial rotation (P = 0.058). During lateral therapy, there was statistically more motion in flexion-extension and lateral bending with the manual log-roll technique (P < 0.001). The total motion was decreased by more than 50% in each plane when using an alternative to log-roll techniques during the total sequence (P < 0.006). CONCLUSION: We have demonstrated the total angular motion incurred to the unstable cervical spine as experienced by the typical trauma patient from the field to stabilization in the operating room using the best compared with the most commonly used techniques. As previously reported, using log-roll techniques consistently results in unwanted motion at the injured spinal segment.

Comparison of external fixation versus the trauma pelvic orthotic device on unstable pelvic injuries: a cadaveric study of stability.

BACKGROUND: Most institutions treating pelvic fractures use some method of acute mechanical stabilization. This typically involves use of pelvic binders or circumferential sheeting, and/or external fixation. The comparative value of these different modalities is controversial. We hypothesized that an external fixator would provide more stability to an unstable pelvic injury than a commercially available binder device (trauma pelvic orthotic device [T-POD]). METHODS: Unstable pelvic injuries (Tile C) were surgically created in five fresh whole human cadavers. Electromagnetic sensors were placed on the same position of each hemipelvis. The amount of angular motion during testing was measured using a Fastrak, three-dimensional, electromagnetic motion analysis device. Maximum displacements were recorded during application of the stabilizing devices, bed transfer, logrolling, and head-of-bed elevation. External fixation frames were constructed by placing two 5.0-mm half pins into the iliac crest and then connected them with a 10-mm curved bar. The T-POD device was placed at the level of the greater trochanters as per manufacturer's recommendations. RESULTS: While logrolling the patient and performing bed transfers, the T-POD conferred more stability in all planes of motion, although this did not reach statistical significance. During elevation of the head of the bed, the T-POD allowed less motion in the sagittal and coronal planes but permitted equivalent motion in axial rotation. These differences were not statistically significant. CONCLUSION: There were no significant differences in stability conferred by an external fixator or a T-POD for unstable pelvic injuries. We advocate acute, temporary stabilization of pelvic injuries with a binder device and early conversion to internal fixation when the patient's medical condition allows.

Mechanosensing in actin stress fibers revealed by a close correlation between force and protein localization.

The mechanics of the actin cytoskeleton have a central role in the regulation of cells and tissues, but the details of how molecular sensors recognize deformations and forces are elusive. By performing cytoskeleton laser nanosurgery in cultured epithelial cells and fibroblasts, we show that the retraction of stress fibers (SFs) is restricted to the proximity of the cut and that new adhesions form at the retracting end. This suggests that SFs are attached to the substrate. A new computational model for SFs confirms this hypothesis and predicts the distribution and propagation of contractile forces along the SF. We then analyzed the dynamics of zyxin, a focal adhesion protein present in SFs. Fluorescent redistribution after laser nanosurgery and drug treatment shows a high correlation between the experimentally measured localization of zyxin and the computed localization of forces along SFs. Correlative electron microscopy reveals that zyxin is recruited very fast to intermediate substrate anchor points that are highly tensed upon SF release. A similar acute localization response is found if SFs are mechanically perturbed with the cantilever of an atomic force microscope. If actin bundles are cut by nanosurgery in living Drosophila egg chambers, we also find that zyxin redistribution dynamics correlate to force propagation and that zyxin relocates at tensed SF anchor points, demonstrating that these processes also occur in living organisms. In summary, our quantitative analysis shows that force and protein localization are closely correlated in stress fibers, suggesting a very direct force-sensing mechanism along actin bundles.

Nonsurgical treatment of lumbosacral blastomycosis involving L2-S1: a case report.

STUDY DESIGN: A case report and clinical discussion. OBJECTIVE: To discuss the diagnosis and treatment of Blastomyces dermatitidis in the spine. SUMMARY OF BACKGROUND DATA: Blastomycosis, like other fungal organisms, has a nonspecific appearance on radiographs, and is often mistaken for TB or a neoplasm. Nonsurgical treatment of this infection is possible, however, as seen in this case. The difficulty in diagnosing fungal infections often leads to a delay in treatment. METHODS: We report on a 37-year-old Arabian woman who presented initially with progressive low back and anterior thigh pain without precipitating trauma. She was found to have 2 draining fistulas. Computed tomography-guided percutaneous drainage of the paravertebral phlegmon yielded purulent material that was pan cultured. The KOH preparation was consistent with a fungal pathogen, which was later identified as Blastomyces dermatitidis by polymerase chain reaction. RESULTS: Radiologic studies of the lumbar spine and sacrum performed revealed extensive involvements with osseous destruction of L2-S1. The destruction was most severe at L3 with mild boney retropulsion at that level. Throughout the patient's treatment course, she complained of mild-to-moderate lower back pain and had no neurologic symptoms. Therefore, surgery was deferred. CONCLUSION: There are no pathognomonic findings of blastomycosis on magnetic resonance imaging. Fungal osteomyelitis is rarely identified in this country, and blastomycosis is even less often diagnosed. This case illustrates that fungal osteomyelitis should be considered in the radiographic differential diagnosis until a definitive diagnosis is made through biopsy.

A screening procedure for prioritizing riparian management.

A spatially explicit linear, additive model was developed for quantifying site characteristics of riparian areas of the lower Cedar River, Washington, USA. The spatial complexity and distribution of combined habitat and anthropogenic landscape features were used to define habitat "indices" that indicate the relative quality of riparian habitats. Patches of contiguous grid cells were measured in terms of their locations, sizes, and relative degree of fragmentation. Additionally, intrapatch heterogeneity was measured to identify unique combinations of habitat and anthropogenic factors for individual grid cells within patches. Model verification indicated that existing floodplain riparian habitats received positive indices more than 90% of the time. Mean patch sizes and fragmentation indices were similar for all positive indices throughout the reaches in the valley floor. Among all reaches, reach 7 had the highest number of positive patches due to a higher degree of meandering in this reach. This procedure and model outputs provide unique screening opportunities for prioritizing management of riparian areas (e.g., conservation, restoration and enhancement).