Multimorbidity in persons with non-traumatic spinal cord injury and its impact on healthcare utilization and health outcomes.

STUDY DESIGN: Cross-sectional survey in Canada. OBJECTIVES: To explore multimorbidity (the coexistence of two/more health conditions) in persons with non-traumatic spinal cord injury (NTSCI) and evaluate its impact on healthcare utilization (HCU) and health outcomes. SETTING: Community-dwelling persons. METHODS: Data from the Spinal Cord Injury Community Survey (SCICS) was used. A multimorbidity index (MMI) consisting of 30 secondary health conditions (SHCs), the 7-item HCU questionnaire, the Short Form-12 (SF-12), Life Satisfaction-11 first question, and single-item Quality of Life (QoL) measure were administered. Additionally, participants were grouped as "felt needed healthcare was received" (Group 1, n = 322) or "felt needed healthcare was not received" (Group 2, n = 89) using the HCU question. Associations among these variables were assessed using multivariable analysis. RESULTS: 408 of 412 (99%) participants with NTSCI reported multimorbidity. Constipation, spasticity, and fatigue were the most prevalent self-reported SHCs. Group 1 had a higher MMI score compared to Group 2 (p < 0.001). A higher MMI score correlated with the feeling of not receiving needed care (OR 1.4, 95% CI 1.08-1.21), lower SF-12 (physical/mental component summary scores), being unsatisfied with life, and lower QoL (all p < 0.001). Additionally, Group 1 had more females (p < 0.001), non-Caucasians (p = 0.034), and lower personal annual income (p = 0.025). CONCLUSIONS: Persons with NTSCI have multimorbidity, and the MMI score was associated with increased HCU and worse health outcomes. This work emphasizes the critical need for improved healthcare and monitoring. Future work determining specific thresholds for the MMI could be helpful for triage screening to identify persons at higher risk of poor outcomes.

Echinacea biotechnology: advances, commercialization and future considerations.

CONTEXT: Plants of the genus Echinacea (Asteraceae) are among the most popular herbal supplements on the market today. Recent studies indicate there are potential new applications and emerging markets for this natural health product (NHP). OBJECTIVE: This review aims to synthesize recent developments in Echinacea biotechnology and to identify promising applications for these advances in the industry. METHODS: A comprehensive survey of peer-reviewed publications was carried out, focusing on Echinacea biotechnology and impacts on phytochemistry. This article primarily covers research findings since 2007 and builds on earlier reviews on the biotechnology of Echinacea. RESULTS: Bioreactors, genetic engineering and controlled biotic or abiotic elicitation have the potential to significantly improve the yield, consistency and overall quality of Echinacea products. Using these technologies, a variety of new applications for Echinacea can be realized, such as the use of seed oil and antimicrobial and immune boosting feed additives for livestock. CONCLUSIONS: New applications can take advantage of the well-established popularity of Echinacea as a NHP. Echinacea presents a myriad of potential health benefits, including anti-inflammatory, anxiolytic and antibiotic activities that have yet to be fully translated into new applications. The distinct chemistry and bioactivity of different Echinacea species and organs, moreover, can lead to interesting and diverse commercial opportunities.

Pilot Study of the Mirabilis System Prototype for Rapid Noninvasive Uterine Myoma Treatment Using an Ultrasound-Guided Volumetric Shell Ablation Technique.

STUDY OBJECTIVE: The primary objective of this pilot study was to evaluate the safety and acute tissue ablation efficacy of a transabdominal high-intensity focused ultrasound (HIFU) prototype device that uses ultrasound imaging guidance for rapid noninvasive ablation of uterine myomas. The secondary objective was to assess preliminary myoma-related symptom improvement and myoma volume reduction at 3 to 6 months post-treatment in subsets of patients. DESIGN: Multicenter prospective single-arm pilot study (Canadian Task Force classification II-2). SETTING: University-affiliated teaching hospital and private community hospital. PATIENTS: Women with a diagnosis of symptomatic uterine myomas planning to undergo hysterectomy. INTERVENTIONS: Seventy-three women underwent transabdominal ultrasound-guided HIFU treatment using a volumetric ablation technique referred to as "shell ablation," in which the HIFU energy is deposited in patterns that partially encapsulate the peripheral region of the targeted myoma(s). Patients were divided into 2 sequential cohorts, the development cohort (the first 37 patients treated) and the validation cohort (the final 36 patients treated). Development cohort treatments were performed for dose-ranging purposes to identify the optimum HIFU treatment parameters, whereas the validation cohort treatments were performed to validate these final settings. Sixty-five patients (89.0%) received only prophylactic oral, sublingual, or intramuscular analgesia before treatment, sometimes with oral anxiolytics. The remaining 8 patients (11.0%) were anesthetized before treatment. Sixty-seven patients (91.8%) then had scheduled hysterectomies between 0 and 179 days after treatment completion. Adverse events were monitored until study exit, which ranged from 10 to 191 days post-treatment. MEASUREMENTS AND MAIN RESULTS: The primary efficacy endpoint measured in all 73 patients was the nonperfused volume (NPV) of tissue produced, which was assessed between 0 and 7 days post-treatment either by tissue sectioning after hysterectomy or by gadolinium-enhanced magnetic resonance imaging. Secondary efficacy endpoints were also measured in subsets of patients who were prospectively scheduled for delayed hysterectomies: Changes in menstrual blood loss (MBL), symptom severity (SS), and quality of life (QOL) scores were assessed using validated techniques at 3 months post-treatment in 10 patients and changes in treated myoma volume were assessed using magnetic resonance imaging at 3 to 6 months post-treatment in 14 patients. In all 73 patients, there were no reports of any serious adverse device effects, including no damage to any extrauterine collateral tissues or the abdominal skin. In the development cohort, a mean NPV of 17.9 ± 24.9 cm3 (range, 0-123.0) was produced in a mean total treatment time of 4.9 ± 2.4 minutes (range, 1.1-11.3). These metrics improved in the validation cohort, where a mean NPV of 44.9 ± 58.5 cm3 (range, 0-284.7) was produced in a mean total treatment time of 3.6 ± 2.1 minutes (range, 1.5-9.5). In the subsets of patients with data available, there was a significant improvement in QOL score (median, 16.5 point increase; p = .011), an improving trend in SS score (median, 13.5 point decrease; p = .254), and a significant improvement in treated myoma volume (mean, 24.0% decrease; p = .013). In 8 patients who had above-average MBL scores at baseline and regular menstrual cycle lengths during follow-up, there was also a significant improvement in MBL score (median, 40.8% decrease; p = .035). CONCLUSION: Ultrasound-guided HIFU ablation with the prototype device demonstrated an excellent safety profile and produced clinically relevant NPVs in a mean total treatment time of under 4 minutes using the final validated treatment settings. Short-term clinical efficacy metrics assessed in subsets of patients were encouraging, and larger studies should be conducted to confirm these results (ClinicalTrials.gov, NCT01946178).

Yeast alter micro-oxygenation of wine: oxygen consumption and aldehyde production.

BACKGROUND: Micro-oxygenation (MOx) is a common winemaking treatment used to improve red wine color development and diminish vegetal aroma, amongst other effects. It is commonly applied to wine immediately after yeast fermentation (phase 1) or later, during aging (phase 2). Although most winemakers avoid MOx during malolactic (ML) fermentation, it is often not possible to avoid because ML bacteria are often present during phase 1 MOx treatment. We investigated the effect of common yeast and bacteria on the outcome of micro-oxygenation. RESULTS: Compared to sterile filtered wine, Saccharomyces cerevisiae inoculation significantly increased oxygen consumption, keeping dissolved oxygen in wine below 30 µg L-1 during micro-oxygenation, whereas Oenococcus oeni inoculation was not associated with a significant impact on the concentration of dissolved oxygen. The unfiltered baseline wine also had both present, although with much higher populations of bacteria and consumed oxygen. The yeast-treated wine yielded much higher levels of acetaldehyde, rising from 4.3 to 29 mg L-1 during micro-oxygenation, whereas no significant difference was found between the bacteria-treated wine and the filtered control. The unfiltered wine exhibited rapid oxygen consumption but no additional acetaldehyde, as well as reduced pyruvate. Analysis of the acetaldehyde-glycerol acetal levels showed a good correlation with acetaldehyde concentrations. CONCLUSION: The production of acetaldehyde is a key outcome of MOx and it is dramatically increased in the presence of yeast, although it is possibly counteracted by the metabolism of O. oeni bacteria. Additional controlled experiments are necessary to clarify the interaction of yeast and bacteria during MOx treatments. Analysis of the glycerol acetals may be useful as a proxy for acetaldehyde levels. © 2017 Society of Chemical Industry.

Erythromelalgia involving the face.

Erythromelalgia is a rare disorder characterized by burning pain, erythema, and increased temperature typically involving the distal extremities. Although it can progress to involve the face, erythromelalgia presenting only on the face is particularly rare. This disorder is often misdiagnosed when it presents on the extremities and is even more likely to be misdiagnosed when presenting only on the face, delaying appropriate treatment and causing considerable frustration for the patient. We report a case of a 26-year-old woman with erythromelalgia that involved only the face for a number of years and was treated unsuccessfully as rosacea, seborrheic dermatitis, and contact dermatitis. She subsequently developed involvement of the ears and hands in the more typical distribution of erythromelalgia. We discuss the differential diagnosis of erythromelalgia involving the face and extremities, the proposed pathogenesis and management of the disorder, and the psychological distress this condition can cause. Even when the correct diagnosis of erythromelalgiais made, treatment is difficult, with no single therapy consistently effective.

Deafness, pregnancy and sexual health.

This article exposes the need for support for midwives, to ensure that they are equipped to meet the needs of deaf parents to be. It uncovers research which demonstrates the urgent need for an increase in awareness, education and resources; and the reasons that deaf people have higher rates of teenage pregnancy and sexually transmitted infections than the general population. With stories from midwives at a loss as to how to communicate with deaf mothers in labour, and stories from deaf women who can't understand their health professionals, nor read the literature that has been given to them--this is thought provoking reading.

Network analysis of multimorbidity and health outcomes among persons with spinal cord injury in Canada.

Introduction: Multimorbidity, defined as the coexistence of two or more health conditions, is common in persons with spinal cord injury (SCI). Network analysis is a powerful tool to visualize and examine the relationship within complex systems. We utilized network analysis to explore the relationship between 30 secondary health conditions (SHCs) and health outcomes in persons with traumatic (TSCI) and non-traumatic SCI (NTSCI). The study objectives were to (1) apply network models to the 2011-2012 Canadian SCI Community Survey dataset to identify key variables linking the SHCs measured by the Multimorbidity Index-30 (MMI-30) to healthcare utilization (HCU), health status, and quality of life (QoL), (2) create a short form of the MMI-30 based on network analysis, and (3) compare the network-derived MMI to the MMI-30 in persons with TSCI and NTSCI. Methods: Three network models (Gaussian Graphical, Ising, and Mixed Graphical) were created and analyzed using standard network measures (e.g., network centrality). Data analyzed included demographic and injury variables (e.g., age, sex, region of residence, date, injury severity), multimorbidity (using MMI-30), HCU (using the 7-item HCU questionnaire and classified as "felt needed care was not received" [HCU-FNCNR]), health status (using the 12-item Short Form survey [SF-12] Physical and Mental Component Summary [PCS-12 and MCS-12] score), and QoL (using the 11-item Life Satisfaction questionnaire [LiSAT-11] first question and a single item QoL measure). Results: Network analysis of 1,549 participants (TSCI: 1137 and NTSCI: 412) revealed strong connections between the independent nodes (30 SHCs) and the dependent nodes (HCU-FNCNR, PCS-12, MCS-12, LiSAT-11, and the QoL score). Additionally, network models identified that cancer, deep vein thrombosis/pulmonary embolism, diabetes, high blood pressure, and liver disease were isolated. Logistic regression analysis indicated the network-derived MMI-25 correlated with all health outcome measures (p <0.001) and was comparable to the MMI-30. Discussion: The network-derived MMI-25 was comparable to the MMI-30 and was associated with inadequate HCU, lower health status, and poor QoL. The MMI-25 shows promise as a follow-up screening tool to identify persons living with SCI at risk of having poor health outcomes.

Polyploidization for the Genetic Improvement of Cannabis sativa.

Cannabis sativa L. is a diploid species, cultivated throughout the ages as a source of fiber, food, and secondary metabolites with therapeutic and recreational properties. Polyploidization is considered as a valuable tool in the genetic improvement of crop plants. Although this method has been used in hemp-type Cannabis, it has never been applied to drug-type strains. Here, we describe the development of tetraploid drug-type Cannabis lines and test whether this transformation alters yield or the profile of important secondary metabolites: Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), or terpenes. The mitotic spindle inhibitor oryzalin was used to induce polyploids in a THC/CBD balanced drug-type strain of Cannabis sativa. Cultured axillary bud explants were exposed to a range of oryzalin concentrations for 24 h. Flow cytometry was used to assess the ploidy of regenerated shoots. Treatment with 20-40 µM oryzalin produced the highest number of tetraploids. Tetraploid clones were assessed for changes in morphology and chemical profile compared to diploid control plants. Tetraploid fan leaves were larger, with stomata about 30% larger and about half as dense compared to diploids. Trichome density was increased by about 40% on tetraploid sugar leaves, coupled with significant changes in the terpene profile and a 9% increase in CBD that was significant in buds. No significant increase in yield of dried bud or THC content was observed. This research lays important groundwork for the breeding and development of new Cannabis strains with diverse chemical profiles, of benefit to medical and recreational users.

Filling the Gap: Simulation-based Crisis Resource Management Training for Emergency Medicine Residents.

INTRODUCTION: In today's team-oriented healthcare environment, high-quality patient care requires physicians to possess not only medical knowledge and technical skills but also crisis resource management (CRM) skills. In emergency medicine (EM), the high acuity and dynamic environment makes CRM skills of physicians particularly critical to healthcare team success. The Accreditation Council of Graduate Medicine Education Core Competencies that guide residency program curriculums include CRM skills; however, EM residency programs are not given specific instructions as to how to teach these skills to their trainees. This article describes a simulation-based CRM course designed specifically for novice EM residents. METHODS: The CRM course includes an introductory didactic presentation followed by a series of simulation scenarios and structured debriefs. The course is designed to use observational learning within simulation education to decrease the time and resources required for implementation. To assess the effectiveness in improving team CRM skills, two independent raters use a validated CRM global rating scale to measure the CRM skills displayed by teams of EM interns in a pretest and posttest during the course. RESULTS: The CRM course improved leadership, problem solving, communication, situational awareness, teamwork, resource utilization and overall CRM skills displayed by teams of EM interns. While the improvement from pretest to posttest did not reach statistical significance for this pilot study, the large effect sizes suggest that statistical significance may be achieved with a larger sample size. CONCLUSION: This course can feasibly be incorporated into existing EM residency curriculums to provide EM trainees with basic CRM skills required of successful emergency physicians. We believe integrating CRM training early into existing EM education encourages continued deliberate practice, discussion, and improvement of essential CRM skills.

Changing Systems Through Effective Teams: A Role for Simulation.

Teams are the building blocks of the healthcare system, with growing evidence linking the quality of healthcare to team effectiveness, and team effectiveness to team training. Simulation has been identified as an effective modality for team training and assessment. Despite this, there are gaps in methodology, measurement, and implementation that prevent maximizing the impact of simulation modalities on team performance. As part of the 2017 Academic Emergency Medicine Consensus Conference "Catalyzing System Change Through Health Care Simulation: Systems, Competency, and Outcomes," we explored the impact of simulation on various aspects of team effectiveness. The consensus process included an extensive literature review, group discussions, and the conference "workshop" involving emergency medicine physicians, medical educators, and team science experts. The objectives of this work were to: 1) explore the antecedents and processes that support team effectiveness, 2) summarize the current role of simulation in developing and understanding team effectiveness, and 3) identify research targets to further improve team-based training and assessment, with the ultimate goal of improving healthcare systems.

Spatial variability in acoustic backscatter as an indicator of tissue homogenate production in pulsed cavitational ultrasound therapy.

Spatial variability in acoustic backscatter is investigated as a potential feedback metric for assessment of lesion morphology during cavitation-mediated mechanical tissue disruption ("histotripsy"). A 750-kHz annular array was aligned confocally with a 4.5 MHz passive backscatter receiver during ex vivo insonation of porcine myocardium. Various exposure conditions were used to elicit a range of damage morphologies and backscatter characteristics [pulse duration = 14 micros, pulse repetition frequency (PRF) = 0.07-3.1 kHz, average I(SPPA) = 22-44 kW/cm2]. Variability in backscatter spatial localization was quantified by tracking the lag required to achieve peak correlation between sequential RF A-lines received. Mean spatial variability was observed to be significantly higher when damage morphology consisted of mechanically disrupted tissue homogenate versus mechanically intact coagulation necrosis (2.35 +/- 1.59 mm versus 0.067 +/- 0.054 mm, p < 0.025). Statistics from these variability distributions were used as the basis for selecting a threshold variability level to identify the onset of homogenate formation via an abrupt, sustained increase in spatially dynamic backscatter activity. Specific indices indicative of the state of the homogenization process were quantified as a function of acoustic input conditions. The prevalence of backscatter spatial variability was observed to scale with the amount of homogenate produced for various PRFs and acoustic intensities.

Pulsed cavitational ultrasound therapy for controlled tissue homogenization.

Methods were investigated to acoustically control the extent to which cavitation-mediated tissue homogenization is responsible for lesion formation in vitro. These results may guide potential therapeutic procedures that induce damage predominantly via mechanical disruption and, thereby, avoid limitations associated with thermal ablative modalities. Porcine myocardium was insonified at 750 kHz using pulse sequences consisting of high-amplitude pulses (22 MPa Pr) interleaved with variable-amplitude "sustaining" pulses (e.g., 6.9 MPa Pr), which were intended to provide sufficient acoustic input to maintain cavitation activity between primary pulses, but to increase the spatial peak temporal average intensity (I(SPTA)) only marginally. Using modest temporal-average intensities (e.g., I(SPTA) approximately 200 W/cm2), approximately 0.5 cm3 lesions were produced consisting of homogenate that could be irrigated away to reveal smooth cavities. The prevalence of homogenate in a given lesion was sensitive to both pulse-repetition frequency and sustaining pulse amplitude, suggesting the existence of optimum acoustic parameters for producing homogenized lesions largely via mechanical perturbation.

Cerium chloride heptahydrate (CeCl3 · 7H2O) induces muscle paralysis in the generalist herbivore, Melanoplus sanguinipes (Fabricius) (Orthoptera: Acrididae), fed contaminated plant tissues.

Of increasing economic importance are the rare earth elements (REEs). Pollution from mining and processing activity is expected to rise with industrial demand. Plants are known to accumulate REEs, although levels vary with species and soil content. However, the effect on wildlife of ingesting REE contaminated vegetation is not well understood. Here we examined the effect of consuming vegetation with elevated levels of cerium on the generalist grasshopper, Melanoplus sanguinipes (Fabricius). Adults excreted a substantial portion of ingested contamination. However, after only four-days of feeding, accumulation in the body occurred at all doses and paralysis of appendages resulted at the highest doses. Short-term toxicity studies may underestimate the impact of ingesting REE contamination. Metals tend to be low in toxicity; however, their persistence in the environment may be better represented by exposure over longer portions of the life cycle.

Uptake and Effects of Six Rare Earth Elements (REEs) on Selected Native and Crop Species Growing in Contaminated Soils.

Rare earth elements (REEs) have become increasingly important metals used in modern technology. Processes including mining, oil refining, discarding of obsolete equipment containing REEs, and the use of REE-containing phosphate fertilizers may increase the likelihood of environmental contamination. However, there is a scarcity of information on the toxicity and accumulation of these metals to terrestrial primary producers in contaminated soils. The objective of this work was to assess the phytotoxicity and uptake from contaminated soil of six REEs (chloride forms of praseodymium, neodymium, samarium, terbium, dysprosium, and erbium) on three native plants (Asclepias syriaca L., Desmodium canadense (L.) DC., Panicum virgatum L.) and two crop species (Raphanus sativus L., Solanum lycopersicum L.) in separate dose-response experiments under growth chamber conditions. Limited effects of REEs were found on seed germination and speed of germination. Effects on aboveground and belowground biomass were more pronounced, especially for the three native species, which were always more sensitive than the crop species tested. Inhibition concentrations (IC25 and IC50) causing 25 or 50% reductions in plant biomass respectively, were measured. For the native species, the majority of aboveground biomass IC25s (11 out of 18) fell within 100 to 300 mg REE/kg dry soil. In comparison to the native species, IC25s for the crops were always greater than 400 mg REE/kg, with the majority of results (seven out of 12) falling above 700 mg REE/kg. IC50s were often not detected for the crops. Root biomass of native species was also affected at lower doses than in crops. REE uptake by plants was higher in the belowground parts than in the above-ground plant tissues. Results also revealed that chloride may have contributed to the sensitivity of the native species, Desmodium canadense, one of the most sensitive species studied. Nevertheless, these results demonstrated that phytotoxicity may be a concern in contaminated areas.

Electrochemical monitoring of transport by a vesicular monoamine transporter expressed in Xenopus oocytes.

Xenopus laevis oocytes were injected with synthetic mRNA coding for a rat VMAT2 mutant (rVMAT2-I483A/L484A) shown previously to be retained on the plasma membrane as a result of a presumed reduction of endocytosis. Binding of the specific VMAT inhibitor [3H]dihydrotetrabenazine indicated that expression did occur at a level of approximately 3 fmol per oocyte. To determine if rVMAT2-I483A/L484A expressed in oocytes was capable of substrate transport, oocytes were placed in buffer at pH 6.0, dopamine substrate was injected into the cell, and egress of substrate was monitored by fast scan cyclic voltammetry using a carbon fiber microelectrode. Under these conditions, transport by oocytes injected with RNA coding for rVMAT2-I483A/L484A ranged from approximately 0.5 to more than 2.5 pmol/min. Water-injected and uninjected control oocytes did not exhibit appreciable transport activity. Transport by rVMAT2-I483A/L484A-injected oocytes was reduced to control levels by tetrabenazine, a known inhibitor of VMAT transport activity. Comparison of subtracted voltammograms obtained from transport assays with those for calibration experiments confirmed that the transported species was dopamine. These results suggest that expression of VMATs in oocytes may provide a useful model system for mechanistic and regulatory studies that would not be feasible using traditional methods.

Investigation of a safety-engineered device to prevent needlestick injury: why has not StatLock stuck?

OBJECTIVE: This article sought to define whether an alternative safety-engineered device (SED) could help prevent needlestick injury (NSI) in healthcare workers (HCWs) who place central venous catheters (CVCs). DESIGN: The study involved three phases: (1) A retrospective analysis of deidentified occupational health records from our tertiary care urban US hospital to clearly identify NSI risk and rates to an HCW during invasive catheter placement; (2) 95 residents were surveyed regarding their knowledge and experience with NSIs and SEDs; (3) A random sample of six residents participated in a focus group session discussing barriers to the use of SED. SETTING: A single urban US tertiary care teaching hospital. PARTICIPANTS: A retrospective analysis of NSI to HCWs in a tertiary care urban US hospital was conducted over a 4-year period (July 2007-June 2011). Ninety-five residents from specialties that often place CVC during training (surgery, surgical subspecialties, internal medicine, anaesthesia and emergency medicine) were surveyed regarding their experience with NSIs and SEDs. A random sample of six residents participated in a focus group session discussing barriers to the use of SED. RESULTS: 314 NSIs were identified via occupational health records. 16% (21 of 131) of NSIs occurring in residents and fellows occurred during the securement of an invasive catheter such as a CVC. If an SED device had been used, the 5.25 NSIs/year could have been avoided. Each NSI occurring in an HCW incurred at least $2723 in charges. Thus, utilisation of the SED could have saved a minimum of $57 183 over the 4-year period. CONCLUSIONS: SEDs are currently available and can be used as an alternative to sharps. If safety and efficacy can be demonstrated, then implementation of such devices can significantly reduce the number of NSIs.

Refining histotripsy: defining the parameter space for the creation of nonthermal lesions with high intensity, pulsed focused ultrasound of the in vitro kidney.

PURPOSE: Focused ultrasound therapy is a promising modality for noninvasive tissue ablation. However, the relative contributions of thermal and cavitational effects are poorly defined. We characterized the ultrasound parameters within which tissue ablation occurs by cavitational mechanisms without significant thermal effect. MATERIALS AND METHODS: In vitro porcine kidneys were submerged in degassed water. Tissue ablation was performed by delivering ultrasound (750 kHz and 20 microsecond pulses) of constant spatial peak energy dose (100 J/cm(2)) to adjacent foci in a 3 x 3 grid configuration. For each ablation different intensity (0.11 to 211 kW/cm(2)) and duty cycle (0.04% to 100%) parameters were selected. A thermocouple co-localized with the center of each grid continuously measured temperature. Following ablation each kidney was examined grossly and histologically. RESULTS: Ablated tissue lesions were classified into 4 discrete morphological categories, including blanched--firm, pale, desiccated tissue, disrupted--a cavity containing thin, isochromatic liquid, mixed--a cavity containing pale, thick liquid with minimal blanching and no grossly visible effect. Morphologically similar lesions clustered at separable regions of the ultrasound parameter space. The maximal temperature attained in disrupted lesions was similar to that attained when there was no effect (44.2C and 47.2C, respectively, p = 0.31), although it was significantly lower than the maximal temperatures for desiccated or mixed lesions (67.5C and 59.4C, each p <0.0001). CONCLUSIONS: In an in vitro model we defined the ultrasound parameter region within which purely cavitational ablation of tissue is possible with a negligible thermal component. Additional research is needed to optimize the parameters for in vivo cavitational tissue ablation, incorporating the influence of tissue perfusion.

Cost-effective assembly of a basic fiber-optic hydrophone for measurement of high-amplitude therapeutic ultrasound fields.

Design considerations, assembly details, and operating procedures of one version of a cost-effective basic fiber-optic probe hydrophone (FOPH) are described in order to convey practical information to groups interested in constructing a similar device. The use of fiber optic hydrophones can overcome some of the limitations associated with traditional polyvinylidene difluoride (PVDF) hydrophones for calibration of acoustic fields. Compared to standard PVDF hydrophones, FOPH systems generally have larger bandwidths, enhanced spatial resolution, reduced directionality, and greater immunity to electromagnetic interference, though they can be limited by significantly lower sensitivities. The FOPH system presently described employs a 100-microm multimode optical fiber as the sensing element and incorporates a 1-W laser diode module, 2 x 2 optical coupler, and general-purpose 50-MHz silicon p-i-n photodetector. Wave forms generated using the FOPH system and a reference PVDF hydrophone are compared, and intrinsic and substitution methods for calibrating the FOPH system are discussed. The voltage-to-pressure transfer factor is approximately 0.8 mV/MPa (-302 dB re 1 V/microPa), though straightforward modifications to the optical components in the FOPH system are discussed that can significantly increase this value. Recommendations are presented to guide the choice of optical components and to provide practical insight into the routine usage of the FOPH device.