Role of Noncontrast Computed Tomography Parameters in Predicting the Outcome of Extracorporeal Shock Wave Lithotripsy for Upper Urinary Stones Cases: A Meta-analysis.

RATIONALE: Extracorporeal shock wave lithotripsy (ESWL) is widely considered the primary approach for managing urinary tract stones. This study aimed to assess the predictive factors associated with non-contrast computed tomography (NCCT)-based parameters of upper urinary stones in relation to the outcomes of ESWL. MATERIALS AND METHODS: A systematic search was conducted in PubMed, ScienceDirect, Web of Science, and Cochrane Library to identify all relevant studies published up to June 3, 2023. Several NCCT-based parameters to predict ESWL outcomes, comprised of mean stone density (MSD), skin-to-stone distance (SSD), and stone size, were extracted and analyzed using Review Manager software. RESULTS: Out of 979 publications screened, a total of 39 publications, involving 7869 patients, were enrolled in the analysis. The pooled estimate demonstrated significant differences between MSD, and stone size between successful and failure of stone fragmentation groups, in which lower values of these parameters are associated with successful ESWL outcomes. CONCLUSION: The results from the current study suggested that lower NCCT parameters, notably MSD, SSD, and stone size, are significantly associated with successful ESWL outcome. However, additional large-scale prospective studies are required to utilize these parameters effectively, and the optimal cutoff value should be determined.

L-Carnitine intake and high trimethylamine N-oxide plasma levels correlate with low aortic lesions in ApoE(-/-) transgenic mice expressing CETP.

OBJECTIVE: Dietary l-carnitine can be metabolized by intestinal microbiota to trimethylamine, which is absorbed by the gut and further oxidized to trimethylamine N-oxide (TMAO) in the liver. TMAO plasma levels have been associated with atherosclerosis development in ApoE(-/-) mice. To better understand the mechanisms behind this association, we conducted in vitro and in vivo studies looking at the effect of TMAO on different steps of atherosclerotic disease progression. METHODS: J774 mouse macrophage cells were used to evaluate the effect of TMAO on foam cell formation. Male ApoE(-/-) mice transfected with human cholesteryl ester transfer protein (hCETP) were fed l-carnitine and/or methimazole, a flavin monooxygenase 3 (FMO3) inhibitor that prevents the formation of TMAO. Following 12 week treatment, l-carnitine and TMAO plasma levels, aortic lesion development, and lipid profiles were determined. RESULTS: TMAO at concentrations up to 10-fold the Cmax reported in humans did not affect in vitro foam cell formation. In ApoE(-/-)mice expressing hCETP, high doses of l-carnitine resulted in a significant increase in plasma TMAO levels. Surprisingly, and independently from treatment group, TMAO levels inversely correlated with aortic lesion size in both aortic root and thoracic aorta. High TMAO levels were found to significantly correlate with smaller aortic lesion area. Plasma lipid and lipoprotein levels did not change with treatment nor with TMAO levels, suggesting that the observed effects on lesion area were independent from lipid changes. CONCLUSION: These findings suggest that TMAO slows aortic lesion formation in this mouse model and may have a protective effect against atherosclerosis development in humans.

Combined effects of expectations and visual uncertainty upon detection and identification of a target in the fog.

Detecting a pedestrian while driving in the fog is one situation where the prior expectation about the target presence is integrated with the noisy visual input. We focus on how these sources of information influence the oculomotor behavior and are integrated within an underlying decision-making process. The participants had to judge whether high-/low-density fog scenes displayed on a computer screen contained a pedestrian or a deer by executing a mouse movement toward the response button (mouse-tracking). A variable road sign was added on the scene to manipulate expectations about target identity. We then analyzed the timing and amplitude of the deviation of mouse trajectories toward the incorrect response and, using an eye tracker, the detection time (before fixating the target) and the identification time (fixations on the target). Results revealed that expectation of the correct target results in earlier decisions with less deviation toward the alternative response, this effect being partially explained by the facilitation of target identification.

Handheld real-time volumetric imaging of the spine: technology development.

Technical difficulties, poor image quality and reliance on pattern identifications represent some of the drawbacks of two-dimensional ultrasound imaging of spinal bone anatomy. To overcome these limitations, this study sought to develop real-time volumetric imaging of the spine using a portable handheld device. The device measured 19.2 cm × 9.2 cm × 9.0 cm and imaged at 5 MHz centre frequency. 2D imaging under conventional ultrasound and volumetric (3D) imaging in real time was achieved and verified by inspection using a custom spine phantom. Further device performance was assessed and revealed a 75-min battery life and an average frame rate of 17.7 Hz in volumetric imaging mode. The results suggest that real-time volumetric imaging of the spine is a feasible technique for more intuitive visualization of the spine. These results may have important ramifications for a large array of neuraxial procedures.

Improved elevational and azimuthal motion tracking using sector scans.

Ultrasound data motion tracking is widely used to estimate relative tissue/transducer motion, for example in freehand 3-D imaging, in which successive 2-D ultrasound scan planes are registered in a 3-D volume. Speckle-tracking and decorrelation-based methods are used to estimate motion in the azimuthal and elevational planes. However, the performance of speckle-tracking is significantly degraded in sectorscan systems because of point-spread function rotation with lateral motion. In this paper, we develop a new method for joint azimuthal¿elevational motion estimation based on the complex correlation of individual IQ-demodulated sector-scan A-lines arising from tissue motion in 3-D space. We show that our method has performance benefits over both speckle-tracking and decorrelation-based tracking for motion estimation in sector-scan systems, particularly when there is both elevational and azimuthal motion. Motion-tracking efficacy is further demonstrated by improved freehand imaging of a known target (anatomically accurate 3-D-printed lumbar spine model) in a tissue-mimicking phantom, with an rms surface distance error of 1.2 mm, compared with 2.43 mm for conventional methods. These data indicate that the new algorithm is capable of improved tracking performance for sector scan systems, enabling effective freehand 3-D scanning.

Role of supplementary L-carnitine in exercise and exercise recovery.

L-Carnitine is a conditionally essential nutrient and plays an important role in mitochondrial ß-oxidation. As a dietary supplement for athletes, L-carnitine has been investigated for its potential to enhance ß-oxidation during exercise ultimately to improve performance. While some studies have shown a positive impact on VO(2 max) and other performance measures, other studies have found contradictory results. As such, investigations to a different mechanism by which L-carnitine supplementation could impact exercise and recovery were explored. Based on findings from cardiovascular research that L-carnitine enhances vascular endothelial function, an alternate hypothesis was developed. The hypothesis is centered on improving blood flow to muscle tissues and decreasing hypoxic stress and its resulting sequelae. Studies have shown a decrease in markers of purine catabolism and free radical generation and muscle soreness as a result of L-carnitine supplementation. Direct assessment of muscle tissue damage via magnetic resonance imaging also indicates the ability of L-carnitine to attenuate tissue damage related to hypoxic stress. L-Carnitine is regarded as a safe supplement for athletes and has been shown to positively impact the recovery process after exercise.

Application of X-Y separable 2-D array beamforming for increased frame rate and energy efficiency in handheld devices.

Two-dimensional arrays present significant beamforming computational challenges because of their high channel count and data rate. These challenges are even more stringent when incorporating a 2-D transducer array into a battery-powered hand-held device, placing significant demands on power efficiency. Previous work in sonar and ultrasound indicates that 2-D array beamforming can be decomposed into two separable line-array beamforming operations. This has been used in conjunction with frequency-domain phase-based focusing to achieve fast volume imaging. In this paper, we analyze the imaging and computational performance of approximate near-field separable beamforming for high-quality delay-and-sum (DAS) beamforming and for a low-cost, phase-rotation-only beamforming method known as direct-sampled in-phase quadrature (DSIQ) beamforming. We show that when high-quality time-delay interpolation is used, separable DAS focusing introduces no noticeable imaging degradation under practical conditions. Similar results for DSIQ focusing are observed. In addition, a slight modification to the DSIQ focusing method greatly increases imaging contrast, making it comparable to that of DAS, despite having a wider main lobe and higher side lobes resulting from the limitations of phase-only time-delay interpolation. Compared with non-separable 2-D imaging, up to a 20-fold increase in frame rate is possible with the separable method. When implemented on a smart-phone-oriented processor to focus data from a 60 x 60 channel array using a 40 x 40 aperture, the frame rate per C-mode volume slice increases from 16 to 255 Hz for DAS, and from 11 to 193 Hz for DSIQ. Energy usage per frame is similarly reduced from 75 to 4.8 mJ/ frame for DAS, and from 107 to 6.3 mJ/frame for DSIQ. We also show that the separable method outperforms 2-D FFT-based focusing by a factor of 1.64 at these data sizes. This data indicates that with the optimal design choices, separable 2-D beamforming can significantly improve frame rate and battery life for hand-held devices with 2-D arrays.

The effects of transducer geometry on artifacts common to diagnostic bone imaging with conventional medical ultrasound.

The portability, low cost, and non-ionizing radiation associated with medical ultrasound suggest that it has potential as a superior alternative to X-ray for bone imaging. However, when conventional ultrasound imaging systems are used for bone imaging, clinical acceptance is frequently limited by artifacts derived from reflections occurring away from the main axis of the acoustic beam. In this paper, the physical source of off-axis artifacts and the effect of transducer geometry on these artifacts are investigated in simulation and experimental studies. In agreement with diffraction theory, the sampled linear-array geometry possessed increased off-axis energy compared with single-element piston geometry, and therefore, exhibited greater levels of artifact signal. Simulation and experimental results demonstrated that the linear-array geometry exhibited increased artifact signal when the center frequency increased, when energy off-axis to the main acoustic beam (i.e., grating lobes) was perpendicularly incident upon off-axis surfaces, and when off-axis surfaces were specular rather than diffusive. The simulation model used to simulate specular reflections was validated experimentally and a correlation coefficient of 0.97 between experimental and simulated peak reflection contrast was observed. In ex vivo experiments, the piston geometry yielded 4 and 6.2 dB average contrast improvement compared with the linear array when imaging the spinous process and interlaminar space of an animal spine, respectively. This work indicates that off-axis reflections are a major source of ultrasound image artifacts, particularly in environments comprising specular reflecting (i.e., bone or bone-like) objects. Transducer geometries with reduced sensitivity to off-axis surface reflections, such as a piston transducer geometry, yield significant reductions in image artifact.

Patient-controlled analgesia combined with either ondansetron or ondansetron plus prochlorperazine for control of pain and nausea and vomiting in patients undergoing abdominal surgery.

STUDY OBJECTIVE: To compare ondansetron with ondansetron plus prochlorperazine, added to a patient-controlled analgesia (PCA) solution for control of postoperative nausea and vomiting (PONV). DESIGN: Prospective, randomized, double-blinded study. SETTING: University hospital. PATIENTS: 150 ASA physical status I, II, and III patients undergoing abdominal surgery. INTERVENTIONS: Patients were given a PCA morphine solution containing either 30 mg of ondansetron (Group O), 30 mg of ondansetron plus 20 mg of prochlorperazine (Group OP), or no antiemetic (Group C; control group). MEASUREMENTS: Demographic data were recorded, along with anesthetic and surgical time, total fluid intake, frequency of Postanesthesia Care Unit (PACU) PONV, discharge time and length of stay, frequency of PONV while on the hospital floor, highest nausea scores, total PCA morphine use, and PCA utilization times. MAIN RESULTS: Demographic and intraoperative variables were similar in all groups. In the first 24 hours after surgery, nausea was higher in Group C than Group OP. Emesis in Group C was twice that of either Group O or Group OP. No differences were noted between groups in PACU PONV. Patients receiving ondansetron plus prochlorperazine when on the hospital floor had a lower frequency of nausea, while patients receiving ondansetron alone had a lower frequency of vomiting than did the control group. The adjusted odds of vomiting doubled for every 12 hours for Group C patients when receiving PCA. CONCLUSIONS: Combination antiemetics added to PCA reduced emetic symptoms after abdominal surgery.

MUlti-Dimensional Spline-Based Estimator (MUSE) for motion estimation: algorithm development and initial results.

Image registration and motion estimation play central roles in many fields, including RADAR, SONAR, light microscopy, and medical imaging. Because of its central significance, estimator accuracy, precision, and computational cost are of critical importance. We have previously presented a highly accurate, spline-based time delay estimator that directly determines sub-sample time delay estimates from sampled data. The algorithm uses cubic splines to produce a continuous representation of a reference signal and then computes an analytical matching function between this reference and a delayed signal. The location of the minima of this function yields estimates of the time delay. In this paper we describe the MUlti-dimensional Spline-based Estimator (MUSE) that allows accurate and precise estimation of multi-dimensional displacements/strain components from multi-dimensional data sets. We describe the mathematical formulation for two- and three-dimensional motion/strain estimation and present simulation results to assess the intrinsic bias and standard deviation of this algorithm and compare it to currently available multi-dimensional estimators. In 1000 noise-free simulations of ultrasound data we found that 2D MUSE exhibits maximum bias of 2.6 x 10(-4) samples in range and 2.2 x 10(-3) samples in azimuth (corresponding to 4.8 and 297 nm, respectively). The maximum simulated standard deviation of estimates in both dimensions was comparable at roughly 2.8 x 10(-3) samples (corresponding to 54 nm axially and 378 nm laterally). These results are between two and three orders of magnitude better than currently used 2D tracking methods. Simulation of performance in 3D yielded similar results to those observed in 2D. We also present experimental results obtained using 2D MUSE on data acquired by an Ultrasonix Sonix RP imaging system with an L14-5/38 linear array transducer operating at 6.6 MHz. While our validation of the algorithm was performed using ultrasound data, MUSE is broadly applicable across imaging applications.

Perioperative and long-term operative outcomes after surgery for trigeminal neuralgia: microvascular decompression vs percutaneous balloon ablation.

OBJECTIVES: Numerous medical and surgical therapies have been utilized to treat the symptoms of trigeminal neuralgia (TN). This retrospective study compares patients undergoing either microvascular decompression or balloon ablation of the trigeminal ganglion and determines which produces the best long-term outcomes. METHODS: A 10-year retrospective chart review was performed on patients who underwent microvascular decompression (MVD) or percutaneous balloon ablation (BA) surgery for TN. Demographic data, intraoperative variables, length of hospitalization and symptom improvement were assessed along with complications and recurrences of symptoms after surgery. Appropriate statistical comparisons were utilized to assess differences between the two surgical techniques. RESULTS: MVD patients were younger but were otherwise similar to BA patients. Intraoperatively, twice as many BA patients developed bradycardia compared to MVD patients. 75% of BA patients with bradycardia had an improvement of symptoms. Hospital stay was shorter in BA patients but overall improvement of symptoms was better with MVD. Postoperative complication rates were similar (21% vs 26%) between the BA and MVD groups. DISCUSSION: MVD produced better overall outcomes compared to BA and may be the procedure of choice for surgery to treat TN.

Dietary l-carnitine supplementation improves bone mineral density by suppressing bone turnover in aged ovariectomized rats.

Postmenopausal bone loss is a major public health concern. Although drug therapies are available, women are interested in alternative/adjunct therapies to slow down the bone loss associated with ovarian hormone deficiency. The purpose of this study was to determine whether dietary supplementation of l-carnitine can influence bone density and slow the rate of bone turnover in an aging ovariectomized rat model. Eighteen-month-old Fisher-344 female rats were ovariectomized and assigned to two groups: (1) a control group in which rats were fed ad libitum a carnitine-free (-CN) diet (AIN-93M) and (2) another fed the same diet but supplemented with l-carnitine (+CN). At the end of 8 weeks of feeding, animals were sacrificed and bone specimens were collected for measuring bone mineral content (BMC) and density (BMD) using dual energy X-ray absorptiometry. Femoral microarchitectural properties were assessed by microcomputed tomography. Femoral mRNA levels of selected bone matrix proteins were determined by northern blot analysis. Data showed that tibial BMD was significantly higher in the rat fed the +CN diet than those fed the -CN (control) diet. Dietary carnitine significantly decreased the mRNA level of tartrate-resistant acid phosphatase (TRAP), an indicator of bone resorption by 72.8%, and decreased the mRNA abundance of alkaline phosphatase (ALP) and collagen type-1 (COL), measures of bone formation by 63.6% and 61.2%, respectively. The findings suggest that carnitine supplementation slows bone loss and improves bone microstructural properties by decreasing bone turnover.

L-carnitine increases liver alpha-tocopherol and lowers liver and plasma triglycerides in aging ovariectomized rats.

The objective of this study was to determine whether dietary L-carnitine can influence the status of alpha-tocopherol, retinol and selected lipid parameters in aging ovariectomized rats, an animal model for the menopausal state. Fourteen Fisher-344 female rats 18 months old were acclimated for 4 weeks and ovarectomized. Seven rats per treatment were assigned to either a control group fed ad libitum AIN-93M diet or a carnitine group fed the same diet supplemented with L-carnitine. After an 8-week feeding period, blood and selected tissues were taken for analyses. No differences were noted in food intake, body weight, or organ weights due to L-carnitine. Dietary carnitine significantly increased liver alpha-tocopherol and tended to increase plasma alpha-tocopherol (P<.09). No changes in alpha-tocopherol were observed in other tissues including the brain, lungs and retroperitoneal fat. Retinol levels in plasma and tissues were not affected by supplemental L-carnitine. Significant decreases in liver and plasma triglyceride (TG) levels were noted, suggesting increased utilization of fatty acids. No differences were observed in the fatty acid profile of tissues. The results provide evidence that dietary supplementation of L-carnitine enhances the alpha-tocopherol status and improves the utilization of fat leading to lowering of the liver and plasma levels of TG in aging ovariectomized rats. Whether supplemental L-carnitine may be of benefit to postmenopausal women in lowering plasma TG and improving the antioxidant status remains to be studied.

Standard anesthetic technique for middle ear surgical procedures: a comparison of desflurane and sevoflurane.

OBJECTIVE: This study was designed to compare desflurane and sevoflurane anesthesia for middle ear microsurgery. STUDY DESIGN: One hundred healthy adults undergoing middle ear surgery were assigned to receive either desflurane or sevoflurane as their anesthetic. Intraoperative hemodynamics and BIS numbers were recorded. Hemodynamics, pain, nausea/vomiting, discharge readiness, and other parameters were compared postoperatively and 24 hours later. RESULTS: No intraoperative differences were noted except in BIS scores which trended lower with desflurane. PACU blood pressures were higher after desflurane but pain scores, nausea/vomiting, rescue anti-emetics, recovery scores, and discharge times were similar. A significant difference was noted in anesthetic costs (desflurane > sevoflurane), and in patients with the lowest BIS scores associated with more nausea/vomiting. CONCLUSIONS: Both anesthetics may be used for ototic surgery but propofol anesthesia should still be considered in patients with a history of emetic sequelae. SIGNIFICANCE: Short-acting inhalational anesthetics produce excellent operating conditions and reduce costs for otologic surgery.

Dietary L-carnitine enhances the lymphatic absorption of fat and alpha-tocopherol in ovariectomized rats.

This study was conducted to determine whether the feeding of dietary L-carnitine (CN) improves the intestinal absorption of fat and alpha-tocopherol (alphaTOH) in ovariectomized (OX) rats. OX adult rats were weight-matched and assigned to 2 groups fed a modified AIN-93G diet containing alphaTOH-stripped soybean oil without (-CN) or with (+CN) supplemental CN at 150 mg/kg diet. At 5 wk, each rat with a lymph cannula was infused intraduodenally at 3.0 mL/h with a lipid emulsion consisting of 565 micromol triolein labeled with (14)C ((14)C-OA), 3.6 micromol alphaTOH, and 396 micromol sodium taurocholate in 24 mL PBS buffer. Lymph was collected hourly for 8 h and analyzed for lipids. The lymphatic absorption of alphaTOH for 8 h in +CN rats (899 +/- 201 nmol) was higher (P < 0.05) than in -CN rats (587 +/- 92 nmol). The absorption of (14)C-OA in +CN rats (53.5 +/- 4.0% dose/8 h) also was increased (P < 0.05) compared with -CN rats (47.6 +/- 5.0% dose/8 h). Lymph flow did not differ between the groups. When bile was diverted but with infusion of sodium taurocholate, the lymphatic absorption of lipids did not differ. The present study provides evidence that dietary CN enhances the rates and amounts of lymphatic absorption of alphaTOH and fat in OX rats. Our findings suggest that dietary CN may influence the process of lipid packaging and absorption by the enterocyte in OX rats, and may explain in part the increased status of alphaTOH in CN-fed animals.

Aging and developmental transitions in the B cell lineage.

One explanation for the deterioration of the humoral immune response in elderly individuals is that B lymphopoiesis declines with increasing age. Recent studies report a dramatic decline in pre-B cell numbers in old mice. Surprisingly, the number of mature B cells does not decline with age. To determine if new B cells are made in aged animals despite the drop in pre-B cells, we used 5'-bromo-2-deoxyuridine labeling to determine the production rate of B cells in the bone marrow and spleen of young and old mice. Because of the great variability in the number of early B lineage cells in old mice, we acquired data on >60 young and 50 old mice throughout these experiments. The transitional and mature B cell compartments in the spleen have slower labeling kinetics in old mice as compared to young. By the end of 4 weeks of labeling, an average of only 15% of the mature B cell compartment consists of newly made cells compared to 30% in young mice. However, in contrast to an earlier report, our results indicate that there is no statistical difference in the rate of production of new immature B cells in the marrow of young and old animals. In total, our results confirm previous work showing that mature B cells in old mice have a slower turnover, but more importantly suggest that the defect in mature B cell turnover is not due to a decline in B lymphopoiesis, but rather an inability of the newly made cells to replenish the peripheral compartments.