Associations between biochemical parameters and referral centre in pet rabbits with urolithiasis

OBJECTIVES

To determine the association between signalment, selected haematologic and biochemical parameters and referral centre in pet rabbits with imaging evidence of urolithiasis presented to two veterinary teaching hospitals in North America.

MATERIALS AND METHODS

The medical record database of two veterinary teaching hospitals was searched from 2009 to 2019 for records of pet rabbits that received both imaging studies and plasma biochemistry profiles. Information regarding signalment, bodyweight, packed cell volume, total solids, and plasma biochemistry profiles was obtained. Univariable and multivariable logistic regression models were performed to identify statistically significant parameters associated with imaging evidence of urolithiasis.

RESULTS

Of the 324 examined rabbits, 33 (10.2%) had confirmed evidence of urolithiasis on imaging. Increasing plasma calcium and sodium concentrations and referral centre were significantly associated with the presence of urolithiasis on the univariable logistic regression model. However, only plasma calcium concentration and the referral centre demonstrated significant associations on the multivariable logistic regression model.

CLINICAL SIGNIFICANCE

Results indicate that urolithiasis in pet rabbits that receive imaging is associated with mildly increasing plasma calcium concentration and referral centre. The association with referral centre may indicate there are geographic influences on urolithiasis or on imaging. However, the identified associations have low predictive value for the diagnosis of urolithiasis, indicating the need for additional diagnostic modalities.

A Tissue-Engineered 3D Microvessel Model Reveals the Dynamics of Mosaic Vessel Formation in Breast Cancer

In solid tumors, vascular structure and function varies from the core to the periphery. This structural heterogeneity has been proposed to influence the mechanisms by which tumor cells enter the circulation. Blood vessels exhibit regional defects in endothelial coverage, which can result in cancer cells directly exposed to flow and potentially promoting intravasation. Consistent with prior reports, we observed in human breast tumors and in a mouse model of breast cancer that approximately 6% of vessels consisted of both endothelial cells and tumor cells, so-called mosaic vessels. Due, in part, to the challenges associated with observing tumor-vessel interactions deep within tumors in real-time, the mechanisms by which mosaic vessels form remain incompletely understood. We developed a tissue-engineered model containing a physiologically realistic microvessel in coculture with mammary tumor organoids. This approach allows real-time and quantitative assessment of tumor-vessel interactions under conditions that recapitulate many in vivo features. Imaging revealed that tumor organoids integrate into the endothelial cell lining, resulting in mosaic vessels with gaps in the basement membrane. While mosaic vessel formation was the most frequently observed interaction, tumor organoids also actively constricted and displaced vessels. Furthermore, intravasation of cancer cell clusters was observed following the formation of a mosaic vessel. Taken together, our data reveal that cancer cells can rapidly reshape, destroy, or integrate into existing blood vessels, thereby affecting oxygenation, perfusion, and systemic dissemination. Our novel assay also enables future studies to identify targetable mechanisms of vascular recruitment and intravasation. SIGNIFICANCE: A tissue-engineered microdevice that recapitulates the tumor-vascular microenvironment enables real-time imaging of the cellular mechanisms of mosaic vessel formation and vascular defect generation.

Cerebrovascular plasticity: Processes that lead to changes in the architecture of brain microvessels

The metabolic demands of the brain are met by oxygen and glucose, supplied by a complex hierarchical network of microvessels (arterioles, capillaries, and venules). Transient changes in neural activity are accommodated by local dilation of arterioles or capillaries to increase cerebral blood flow and hence nutrient availability. Transport and communication between the circulation and the brain is regulated by the brain microvascular endothelial cells that form the blood-brain barrier. Under homeostatic conditions, there is very little turnover in brain microvascular endothelial cells, and the cerebrovascular architecture is largely static. However, changes in the brain microenvironment, due to environmental factors, disease, or trauma, can result in additive or subtractive changes in cerebrovascular architecture. Additions occur by angiogenesis or vasculogenesis, whereas subtractions occur by vascular pruning, injury, or endothelial cell death. Here we review the various processes that lead to changes in the cerebrovascular architecture, including sustained changes in the brain microenvironment, development and aging, and injury, disease, and repair.

Specific class of intrapartum antibiotics relates to maturation of the infant gut microbiota: a prospective cohort study

OBJECTIVE

To evaluate the potential impact of intrapartum antibiotics, and their specific classes, on the infant gut microbiota in the first year of life.

DESIGN

Prospective study of infants in the New Hampshire Birth Cohort Study (NHBCS).

SETTINGS

Rural New Hampshire, USA.

POPULATION OR SAMPLE

Two hundred and sixty-six full-term infants from the NHBCS.

METHODS

Intrapartum antibiotic use during labour and delivery was abstracted from medical records. Faecal samples collected at 6 weeks and 1 year of age were characterised by 16S rRNA sequencing, and metagenomics analysis in a subset of samples.

EXPOSURES

Maternal exposure to antibiotics during labour and delivery.

MAIN OUTCOME MEASURE

Taxonomic and functional profiles of faecal samples.

RESULTS

Infant exposure to intrapartum antibiotics, particularly to two or more antibiotic classes, was independently associated with lower microbial diversity scores as well as a unique bacterial community at 6 weeks (GUnifrac, P = 0.02). At 1 year, infants in the penicillin-only group had significantly lower α diversity scores than infants not exposed to intrapartum antibiotics. Within the first year of life, intrapartum exposure to penicillins was related to a significantly lower increase in several taxa including Bacteroides, use of cephalosporins was associated with a significantly lower rise over time in Bifidobacterium and infants in the multi-class group experienced a significantly higher increase in Veillonella dispar.

CONCLUSIONS

Our findings suggest that intrapartum antibiotics alter the developmental trajectory of the infant gut microbiome, and specific antibiotic types may impact community composition, diversity and keystone immune training taxa.

TWEETABLE ABSTRACT

Class of intrapartum antibiotics administered during delivery relates to maturation of infant gut microbiota.

A Simple Colorimetric System for Detecting Target Antigens by a Three-Stage Signal Transformation-Amplification Strategy

Inexpensive, straightforward, and rapid medical diagnostics are becoming increasingly important for disease identification in time- and resource-limited settings. Previous attempts to link oligonucleotide-based aptamers and hammerhead ribozymes to form ligand-induced ribozymes have been successful in identifying a variety of small molecule and protein targets. Isothermal exponential amplification reactions (EXPAR) amplify minute amounts of nucleic acid templates without requiring special instrumentation. We introduce a colorimetric assay that we engineered using an aptamer, hammerhead ribozyme, EXPAR, and peroxidase activity in conjunction with a 3,3',5,5'-tetramethylbenzidine (TMB) substrate. This is a modular signal enhancer system that can be easily modified to detect virtually any chosen analyte target within 5-10 min with minimal technical requirements. Ligand-aptamer binding causes the ribozyme to change conformation and self-cleave. The cleaved ribozyme triggers exponential amplification of a reporter sequence during EXPAR. The amplification products fold into single-stranded DNA guanine quadruplexes that exhibit peroxidase-like activity and can oxidize a colorless TMB substrate into a colored reaction product for visual detection. As a proof of concept, we examined the bronchodilator theophylline versus its chemical analogue, caffeine. We demonstrate linear changes in absorption readout across a wide range of target concentrations (0.5-1000 μM) and the ability to visually detect theophylline at 0.5 μM with an approximately 35-fold increased specificity versus that of caffeine. This three-stage detection system is a versatile platform that has the potential to improve the rapid identification of target analytes.

Tissue-engineered 3D microvessel and capillary network models for the study of vascular phenomena

Advances in tissue engineering, cell biology, microfabrication, and microfluidics have led to the development of a wide range of vascular models. Here, we review platforms based on templated microvessel fabrication to generate increasingly complex vascular models of (i) the tumor microenvironment, (ii) occluded microvessels, and (iii) perfused capillary networks. We outline fabrication guidelines and demonstrate a number of experimental methods for probing vascular function such as permeability measurements, tumor cell intravasation, flow characterization, and endothelial cell morphology and proliferation.

Dissemination from a Solid Tumor: Examining the Multiple Parallel Pathways

Metastasis can be generalized as a linear sequence of events whereby halting one or more steps in the cascade may reduce tumor cell dissemination and ultimately improve patient outcomes. However, metastasis is a complex process with multiple parallel mechanisms of dissemination. Clinical strategies focus on removing the primary tumor and/or treating distant metastases through chemo- or immunotherapies. Successful strategies for blocking metastasis will need to address the parallel mechanisms of dissemination and identify common bottlenecks. Here, we review the current understanding of common dissemination pathways for tumors. Understanding the complexities of metastasis will guide the design of new therapies that halt dissemination.

Mitosis-Mediated Intravasation in a Tissue-Engineered Tumor-Microvessel Platform

Intravasation involves the migration of tumor cells across the local endothelium and escape into vessel flow. Although tumor cell invasiveness has been correlated to increased intravasation, the details of transendothelial migration and detachment into circulation are still unclear. Here, we analyzed the intravasation of invasive human breast cancer cells within a tissue-engineered microvessel model of the tumor microenvironment. Using live-cell fluorescence microscopy, we captured 2,330 hours of tumor cell interactions with functional microvessels and provide evidence for a mitosis-mediated mechanism where tumor cells located along the vessel periphery are able to disrupt the vessel endothelium through cell division and detach into circulation. This model provides a framework for understanding the physical and biological parameters of the tumor microenvironment that mediate intravasation of tumor cells across an intact endothelium. Cancer Res; 77(22); 6453-61. ©2017 AACR.

Abstract 5017: Visualization of the mechanisms of metastasis within a biomimetic engineered tumor microenvironment encompassing a perfusable cylindrical 3D microvessel

Metastasis is responsible for the majority of cancer related deaths; however, many of the biological and physical details surrounding the critical steps (e.g. invasion and intravasation) are largely unknown, in part due to the difficulty in recapitulating and visualizing these dynamic processes. To elucidate these mechanisms, we have developed an in vitro model of invasion and intravasation that comprises tumor cells embedded within an extracellular matrix (ECM) surrounding an engineered microvessel. The microvessel is cylindrical, 150 µm in diameter, and lined with endothelial cells forming a functional barrier that is maintained under constant perfusion at a shear stress of 2-8 dyne cm-2. Using this biomimetic tumor-microvessel platform, we have previously visualized invasion and intravasation of single MDA-MB-231 breast cancer cells into the microvessel and escape into flow. Here, we present mechanistic details of intravasation from both single tumor cells (MDA-MB-231) and mouse mammary tumor organoids (MMTV-PyMT). For single cells, we observe a mitosis-mediated mechanism of intravasation where tumor cell entry into flow is prefaced by cell division at the ECM-vessel interface. For tumor organoids, we see vascular deformation and destabilization from growing tumors that impinge upon proximal vessels, and that bulk intravasation is mediated by shear stress and tumor cell adhesion. As we characterize the various ways in which tumor cells interact with the vessel endothelium and intravasate, we can explore strategies involving the tumor vasculature and clinically relevant drugs to inhibit critical steps in the metastatic cascade.

Citation Format: Andrew D. Wong, Vanesa Silvestri, Anderw J. Ewald, Peter C. Searson. Visualization of the mechanisms of metastasis within a biomimetic engineered tumor microenvironment encompassing a perfusable cylindrical 3D microvessel [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5017. doi:10.1158/1538-7445.AM2017-5017

Abstract 613: In Vitro Microvessels to Study the Platelet-Endothelium Interface

Background: Under normal conditions, endothelial cells (ECs) govern blood flow dynamics including providing a barrier between blood and tissue and regulating platelet aggregation and thrombin generation in the bloodstream. In turn, blood components, primarily platelets and coagulation factors such as thrombin, regulate EC barrier integrity. The breakdown of EC barrier function is a hallmark of a variety of vascular diseases. In sepsis, for example, the dysfunction of vascular ECs has been correlated with poorer outcomes due to hemorrhage and multi-organ failure associated with consumption of platelets and coagulation factors into clots within the microcirculation, a condition termed disseminated intravascular coagulation (DIC).

Aim: Develop an endothelialized flow chamber to study the platelet-endothelium interface.

Methods and Results: We developed a 3D-chamber with a perfuseable cylindrical microvessel embedded in an extracellular matrix (ECM) material. This model allows for the study of the role of thrombin generation and platelet aggregation in endothelial barrier leak development and repair in healthy as well as inflamed microvessels. Incorporation of subendothelial matrix proteins in these 3D-microvessel devices expands the capacity of the microfluidic studies to investigate blood cell extravasation and enables the control of physical parameters such as transmural pressure and interstitial flow through the ECM.

Conclusion: This model may provide insight into the pathophysiology of different disease states and serve as an expedient platform for therapy design and testing.

The platelet-endothelium interface under shear flow. Diagram ( A ) and an experimental prototype ( B ) of a 3D-perfuseable device. Microvessel phenotype (following treatment with vehicle or 10 ng/mL TNFα) pre- and post- perfusion with recalcified whole blood for 33 min as visualized by differential interference contrast, DIC, ( C ) and fluorescence microscopy ( D ).

Real-time quantification of endothelial response to shear stress and vascular modulators

Quiescence is commonly used to describe the inactive state of endothelial cells (ECs) in monolayers that have reached homeostasis. Experimentally quiescence is usually described in terms of the relative change in cell activity (e.g. turnover, speed, etc.) in response to a perturbation (e.g. solute, shear stress, etc.). The objective of this study is to provide new insight into EC quiescence by quantitatively defining the morphology and activity of confluent cell monolayers in response to shear stress and vascular modulators. Confluent monolayers of human umbilical vein ECs (HUVECs) were subjected to a range of shear stresses (4-16 dyne cm-2) under steady flow. Using phase contrast, time-lapse microscopy and image analysis, we quantified EC morphology, speed, proliferation, and apoptosis rates over time and detected differences in monolayer responses under various media conditions: basal media supplemented with growth factors, interleukin-8, or cyclic AMP. In all conditions, we observed a transition from cobblestone to spindle-like morphology in a dose-dependent manner due to shear stress. Cyclic AMP enhanced the elongation and alignment of HUVECs due to shear stress and reduced steady state cell speed. We observed the lowest proliferation rates below 8 dyne cm-2 and found that growth factors and cyclic AMP reduced proliferation and apoptosis; interleukin-8 similarly decreased proliferation, but increased apoptosis. We have quantified the response of ECs in confluent monolayers to shear stress and vascular modulators in terms of morphology, speed, proliferation and apoptosis and have established quantifiable metrics of cell activity to define vascular quiescence under shear stress.

Utility of microfluidic devices to study the platelet-endothelium interface

The integration of biomaterials and understanding of vascular biology has led to the development of perfusable endothelialized flow models, which have been used as valuable tools to study the platelet-endothelium interface under shear. In these models, the parameters of geometry, compliance, biorheology, and cellular complexity are varied to recapitulate the physical biology of platelet recruitment and activation under physiologically relevant conditions of blood flow. In this review, we summarize the mechanistic insights learned from perfusable microvessel models and discuss the potential utility as well as challenges of endothelialized microfluidic devices to study platelet function in the bloodstream in vitro.

Abstract B07: Visualization of the mechanisms of metastasis within a biomimetic engineered tumor microenvironment encompassing a perfusable cylindrical 3D microvessel

Metastasis is responsible for the majority of cancer related deaths; however, many of the biological and physical details surrounding the critical steps (e.g. invasion and intravasation) are largely unknown, in part due to the difficulty in recapitulating and visualizing these dynamic processes. To elucidate these mechanisms, we have developed an in vitro model of invasion and intravasation that comprises tumor cells embedded within an extracellular matrix (ECM) surrounding an engineered microvessel. The microvessel is cylindrical, 150 μm in diameter, and lined with endothelial cells forming a functional barrier that is maintained under constant perfusion at a shear stress of 2-8 dyne cm-2. Using this biomimetic tumor-microvessel platform, we have previously visualized invasion and intravasation of single MDA-MB-231 breast cancer cells into the microvessel and escape into flow. Here, we present mechanistic details of intravasation from both single tumor cells (MDA-MB-231) and mouse mammary tumor organoids (MMTV-PyMT). For single cells, we observe a mitosis-mediated mechanism of intravasation where tumor cell entry into flow is prefaced by cell division at the ECM-vessel interface. For tumor organoids, we see vascular deformation and destabilization from growing tumors that impinge upon proximal vessels, and that bulk intravasation is mediated by shear stress and tumor cell adhesion. As we characterize the various ways in which tumor cells interact with the vessel endothelium and intravasate, we can explore strategies involving the tumor vasculature and clinically relevant drugs to inhibit critical steps in the metastatic cascade.

Citation Format: Andrew D. Wong, Vanesa Silvestri, Andrew J. Ewald, Peter C. Searson. Visualization of the mechanisms of metastasis within a biomimetic engineered tumor microenvironment encompassing a perfusable cylindrical 3D microvessel. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr B07.

In Vitro Tumor Models: Advantages, Disadvantages, Variables, and Selecting the Right Platform

In vitro tumor models have provided important tools for cancer research and serve as low-cost screening platforms for drug therapies; however, cancer recurrence remains largely unchecked due to metastasis, which is the cause of the majority of cancer-related deaths. The need for an improved understanding of the progression and treatment of cancer has pushed for increased accuracy and physiological relevance of in vitro tumor models. As a result, in vitro tumor models have concurrently increased in complexity and their output parameters further diversified, since these models have progressed beyond simple proliferation, invasion, and cytotoxicity screens and have begun recapitulating critical steps in the metastatic cascade, such as intravasation, extravasation, angiogenesis, matrix remodeling, and tumor cell dormancy. Advances in tumor cell biology, 3D cell culture, tissue engineering, biomaterials, microfabrication, and microfluidics have enabled rapid development of new in vitro tumor models that often incorporate multiple cell types, extracellular matrix materials, and spatial and temporal introduction of soluble factors. Other innovations include the incorporation of perfusable microvessels to simulate the tumor vasculature and model intravasation and extravasation. The drive toward precision medicine has increased interest in adapting in vitro tumor models for patient-specific therapies, clinical management, and assessment of metastatic potential. Here, we review the wide range of current in vitro tumor models and summarize their advantages, disadvantages, and suitability in modeling specific aspects of the metastatic cascade and drug treatment.

Poly(ester amide)s with pendant azobenzenes: multi-responsive self-immolative moieties for modulating polymer assemblies

Polymer nanoassemblies containing pendant azobenzenes in their cores were prepared. Light-induced trans–cis isomerization of the azobenzenes increased the polarity of the assembly core, while reduction led to assembly degradation.

Review: in vitro microvessel models

A wide range of perfusable microvessel models have been developed, exploiting advances in microfabrication, microfluidics, biomaterials, stem cell technology, and tissue engineering. These models vary in complexity and physiological relevance, but provide a diverse tool kit for the study of vascular phenomena and methods to vascularize artificial organs. Here we review the state-of-the-art in perfusable microvessel models, summarizing the different fabrication methods and highlighting advantages and limitations.

Human brain microvascular endothelial cells resist elongation due to shear stress

Endothelial cells in straight sections of vessels are known to elongate and align in the direction of flow. This phenotype has been replicated in confluent monolayers of bovine aortic endothelial cells and human umbilical vein endothelial cells (HUVECs) in cell culture under physiological shear stress. Here we report on the morphological response of human brain microvascular endothelial cells (HBMECs) in confluent monolayers in response to shear stress. Using a microfluidic platform we image confluent monolayers of HBMECs and HUVECs under shear stresses up to 16 dyne cm(-2). From live-cell imaging we quantitatively analyze the cell morphology and cell speed as a function of time. We show that HBMECs do not undergo a classical transition from cobblestone to spindle-like morphology in response to shear stress. We further show that under shear stress, actin fibers are randomly oriented in the cells indicating that there is no cytoskeletal remodeling. These results suggest that HBMECs are programmed to resist elongation and alignment under shear stress, a phenotype that may be associated with the unique properties of the blood-brain barrier.

Multiresponsive Azobenzene End-Cap for Self-Immolative Polymers

Azobenzene was introduced as a new multiresponsive end-cap for self-immolative polymers. Using small-molecule model compounds, it was demonstrated that reducing agents including hydrazine and dithiothreitol could reduce the azobenzene to the corresponding hydrazobenzene, resulting in a 1,6-elimination reaction with the potential to initiate the depolymerization of self-immolative polycarbamates. An activated azobenzene derivative was then prepared, allowing for its incorporation as an end-cap for polycarbamates based on alternating N,N'-dimethylethylene diamine and 4-hydroxybenzyl alcohol. Upon treatment with hydrazine, depolymerization proceeded. To demonstrate the versatility of this end-cap, the chemistry was also applied to polycarbamates based on 4-aminobenzyl alcohol. In addition to allowing triggered depolymerization, the azobenzene end-cap also provides a visual signal upon triggering owing to the strong visible absorption of the azobenzene, which shifts to the UV range upon reduction. Furthermore, azobenzene is capable of undergoing trans-cis isomerization in response to UV light, providing multiple functions in a single end-cap.

Live-cell imaging of invasion and intravasation in an artificial microvessel platform

Methods to visualize metastasis exist, but additional tools to better define the biologic and physical processes underlying invasion and intravasation are still needed. One difficulty in studying metastasis stems from the complexity of the interface between the tumor microenvironment and the vascular system. Here, we report the development of an investigational platform that positions tumor cells next to an artificial vessel embedded in an extracellular matrix. On this platform, we used live-cell fluorescence microscopy to analyze the complex interplay between metastatic cancer cells and a functional artificial microvessel that was lined with endothelial cells. The platform recapitulated known interactions, and its use demonstrated the capabilities for a systematic study of novel physical and biologic parameters involved in invasion and intravasation. In summary, our work offers an important new tool to advance knowledge about metastasis and candidate antimetastatic therapies.

The blood-brain barrier: an engineering perspective

It has been more than 100 years since Paul Ehrlich reported that various water-soluble dyes injected into the circulation did not enter the brain. Since Ehrlich's first experiments, only a small number of molecules, such as alcohol and caffeine have been found to cross the blood-brain barrier, and this selective permeability remains the major roadblock to treatment of many central nervous system diseases. At the same time, many central nervous system diseases are associated with disruption of the blood-brain barrier that can lead to changes in permeability, modulation of immune cell transport, and trafficking of pathogens into the brain. Therefore, advances in our understanding of the structure and function of the blood-brain barrier are key to developing effective treatments for a wide range of central nervous system diseases. Over the past 10 years it has become recognized that the blood-brain barrier is a complex, dynamic system that involves biomechanical and biochemical signaling between the vascular system and the brain. Here we reconstruct the structure, function, and transport properties of the blood-brain barrier from an engineering perspective. New insight into the physics of the blood-brain barrier could ultimately lead to clinical advances in the treatment of central nervous system diseases.

Abstract 2827: A platform to study metastatic cancer

Metastasis is responsible for over 90% of cancer related deaths. While significant advances in visualizing metastasis have been made in vivo, the details of the biological and physical processes that govern invasion and intravasation remain poorly understood. The difficulty in studying metastasis stems from the complexity of the interface where invasion and intravasation take place, between the tumor's local tissue microenvironment and the vascular system. To elucidate the mechanistic events taking place during invasion and intravasation, we have developed a platform that positions tumor cells adjacent to an artificial vessel embedded in an extracellular matrix (ECM). Using live-cell, fluorescence microscopy, we study the complex interplay between highly metastatic cancer cells and a functional artificial microvessel lined with endothelial cells during tumor migration and intravasation. We hypothesize that an engineered platform that recapitulates the interactions between a tumor and a physiologically relevant artificial vessel within an extracellular matrix will allow the systematic study of the physical and biological properties that regulate invasion and intravasastion. Since there remain many gaps in our understanding of the biology and physics of invasion and intravasation, further insight into these poorly understood processes may provide new strategies to prevent the spread of cancer and reduce the high mortality rates associated with metastasis.

Citation Format: Andrew D. Wong, Peter C. Searson. A platform to study metastatic cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2827. doi:10.1158/1538-7445.AM2013-2827

Sonographically guided intratendinous injections of hyperosmolar dextrose/lidocaine: a pilot study for the treatment of chronic plantar fasciitis

OBJECTIVE

To report on the effectiveness of sonographically guided injections of hyperosmolar dextrose at reducing the pain associated with chronic plantar fasciitis.

DESIGN

Case series.

SETTING

Ultrasound division of St Paul's Hospital.

PATIENTS

20 referrals (3 men, 17 women; age 51 (SD 13) years) from local sports medicine primary care practitioners who had failed previous conservative treatments.

INTERVENTIONS

A 27-gauge needle administered a 25% dextrose/lidocaine solution under sonographic guidance at 6 week intervals returning for a median of three consultations.

MAIN OUTCOME MEASURES

Visual analogue scale (VAS) items for pain levels at rest (VAS1), activities of daily living (VAS2), and during or after physical activity (VAS3) were recorded at baseline and at the final treatment consultation (post-test). A telephone interview conducted an average of 11.8 months after the post-test consultation provided a measure of long-term follow-up.

RESULTS

16 patients reported a good to excellent outcome, while the symptoms in 4 patients were unchanged. There was a significant decrease (p<0.001) in all mean VAS items from pre-test to post-test: VAS1 (36.8 (SD 25.6) to 10.3 (10.9)), VAS2 (74.7 (20.8) to 25.0 (27.7)) and VAS3 (91.6 (9.2) to 38.7 (35.1)) and there were no apparent changes after the follow-up interview.

CONCLUSIONS

Sonographically guided dextrose injections showed a good clinical response in patients with chronic plantar fasciitis insofar as pain was reduced during rest and activity. Further studies including a control group are needed to validate these outcomes.

Oblique sagittal view of the anterior cruciate ligament: comparison of coronal vs. axial planes as localizing sequences

The purpose of this study was to determine whether oblique sagittal T2-weighted images of the anterior cruciate ligament (ACL) are better prescribed off axial or coronal localizing images. Thirty-one patients underwent two sets of oblique sagittal T2-weighted fast spin-echo sequences to evaluate the ACL. One oblique was prescribed from a coronal localizing sequence, while the other was prescribed off an axial series. Objective (average number of images to demonstrate ACL) and subjective (radiologist's confidence level) evaluations of both sequences were performed independently of the other and then comparatively by two radiologists. The coronally prescribed sagittal oblique was subjectively preferred in 18 patients, the axially prescribed oblique was preferred in one patient, and both sequences were felt to be equivalent in 12 patients. In 13 intact ligaments, the average number of images clearly demonstrating the entire length of the ACL was 1.77 on the coronally prescribed sequence and 1.31 on the axially prescribed images. Oblique sagittal images prescribed off a coronal localizer are both subjectively and objectively more effective than axially prescribed sagittal obliques in evaluating the ACL.

Real-time spatial compound imaging: application to breast, vascular, and musculoskeletal ultrasound

Real-time spatial compound imaging (SonoCT) is an ultrasound technique that uses electronic beam steering of a transducer array to rapidly acquire several (three to nine) overlapping scans of an object from different view angles. These single-angle scans are averaged to form a multiangle compound image that is updated in real time with each subsequent scan. Compound imaging shows improved image quality compared with conventional ultrasound, primarily because of reduction of speckle, clutter, and other acoustic artifacts. Early clinical experience suggests that real-time spatial compound imaging can provide improved contrast resolution and tissue differentiation that is beneficial for imaging the breast, peripheral blood vessels, and musculoskeletal injuries. Future development of real-time spatial compound imaging will help address the bulk of general imaging applications by extending this technology to curved array transducers, tissue harmonics, panoramic imaging, and three-dimensional sonography.

Stratification of prostate-specific antigen level and results of transrectal ultrasonography and digital rectal examination as predictors of positive prostate biopsy

OBJECTIVE

To determine which of several variables--age, serum level of prostate-specific antigen (PSA), findings of transrectal ultrasonography (TRUS) and findings of digital rectal examination (DRE)--are the best predictors of positive prostate biopsy results.

SETTING

An urban, university-affiliated tertiary care hospital.

PATIENTS

a cohort of 1330 consecutive men referred to the diagnostic imaging department for TRUS and TRUS-guided prostate biopsy. Each patient was referred after examination by a urologist because of clinical suspicion of prostate cancer.

METHODS

All of the men had undergone prior determination of serum level of PSA. Repeat DRE was performed at the time of imaging. The variables age, PSA level, TRUS findings and DRE findings were tested aline and in combination as predictors of positive biopsy results by means of logistic regression analysis. A summary of percentage risk for positive biopsy results was constructed for each combination of statistically significant variables, stratified for age.

RESULTS

Cancer was detected in 541 men (40.7%). A strong correlation was observed between serum PSA level and the likelihood of positive biopsy result (p < 0.001). Of 402 men with normal age-specific PSA, 109 (27.1%) had positive biopsy results. Of 403 men with PSA of 10 ng/mL or more, 233 (57.8%) had cancer. The level of serum PSA was also related to the number of prostate sextants harbouring cancer (p < 0.001). TRUS findings at the time of biopsy were a strong predictor of cancer of the PSA level was abnormal (p < 0.001). DRE results alone did not correlate with positive biopsy results, regardless of age, PSA level of TRUS findings.

CONCLUSIONS

Men in whom there is a clinical concern for prostate cancer should undergo prostate biopsy if there is any elevation of age-specific PSA, particularly if the findings of TRUS are also abnormal. Because DRE alone was not predictive of biopsy outcome, algorithms for prostate cancer detection that rely on abnormal DRE results to identify men who should undergo biopsy will miss a significant number of cancers.

Effect of hyoscine butylbromide on gastroesophageal reflux in barium studies of the upper gastrointestinal tract

Hyoscine butylbromide (Buscopan) is an intravenously administered hypotonic agent that significantly reduces pressure in the lower esophageal sphincter and may therefore artificially induce gastroesophageal reflux during barium examination of the upper gastrointestinal tract. This study was performed to test this hypothesis. The presence or absence and severity of gastroesophageal reflux before and after intravenous injection of 20 mg Buscopan were evaluated in 112 consecutive patients undergoing biphasic upper gastrointestinal examination. Gastroesophageal reflux was seen in 49 (44%) of the patients. Reflux was evident both before and after the injection of Buscopan in 35 (31%) of the patients, before injection only in 10 (9%) and after injection only in 4 (4%). The magnitude of reflux after injection of Buscopan was reduced or the same in 108 of the patients (96%) and increased in 4 (4%). There was no significant difference in the overall occurrence (p = 0.41) or degree (p = 0.81) of gastroesophageal reflux before and after injection of Buscopan (chi 2 test). The authors conclude that the routine use of Buscopan is unlikely to spuriously increase the frequency or degree of gastroesophageal reflux observed on upper gastrointestinal barium studies.

Systematic transrectal ultrasound-guided biopsy of the prostate

This study was undertaken to confirm the utility of systematic transrectal ultrasound-guided prostate biopsy in diagnosing cancer in patients with abnormal findings on digital rectal examination or abnormal levels of prostate-specific antigen (or both). The authors also wanted to determine the diagnostic advantage of taking six sextant biopsy samples rather than four quadrant samples. In a prospective study of 669 men examined between July 1992 and April 1993 at a tertiary-care hospital, core samples were obtained from any visualized or palpated abnormalities, the three other "normal" quadrants (apices and bases) and the two parasagittal midzones. The glands of 403 of the patients (60%) had an abnormality detectable by ultrasonography, and 233 of the patients (35%) had adenocarcinoma, proven by histologic examination. Of the 169 cases of adenocarcinoma initially indicated by ultrasonography, the suspected lesion was histologically benign in 66 (39%), but malignancy was found in another portion of the gland. In 18 (8%) of the 233 patients with adenocarcinoma, the only positive result was obtained from the additional core biopsy samples from the midzone. This study confirms that the ultrasonographic characteristics of cancer are variable, that many tumours (130 [56%] in this study) are detected in areas that are normal on ultrasonography and digital rectal examination, and that the detection sensitivity is increased (by 8% in this study) when two midlobe parasagittal plane biopsy samples are added to the four standard quadrant samples.

Differentiation of detached retina and vitreous membrane with color flow Doppler

The sonographic criteria for diagnosis of retinal detachment and vitreous membranes are well established, and in most cases a diagnosis can be made. However, in difficult cases, differentiation between the two may be difficult. In this study the use of high-resolution color flow Doppler was evaluated for differentiating between retinal detachments and vitreous membranes. Sonographic evaluation, including color flow Doppler, was performed in 25 symptomatic eyes. Seven eyes had areas of retinal detachment, all of which had detectable blood flow within at least a portion of the detached retina. Fifteen eyes had vitreous hemorrhages or membranes in which no flow was detected. Two diabetic patients with vitreous membranes and no retinal detachment did have flow detectable within the neovascular membranes. Another patient, who had a complete choroid detachment after surgery, demonstrated good flow within the area of detachment. It is concluded that in difficult cases high-resolution color flow Doppler can enable differentiation of an area of retinal detachment from a vitreous membrane in a patient without diabetes.