Heat Sink Effect on Tumor Ablation Characteristics as Observed in Monopolar Radiofrequency,Bipolar Radiofrequency,and Microwave,Using Ex Vivo Calf Liver Model

Thermal ablation of liver tumors near large blood vessels is affected by the cooling effect of blood flow, leading to incomplete ablation. Hence, we conducted a comparative investigation of heat sink effect in monopolar (MP) and bipolar (BP) radiofrequency ablation (RFA), and microwave (MW) ablation devices.With a perfused calf liver, the ablative performances (volume, mass, density, dimensions), with and without heat sink, were measured. Heat sink was present when the ablative tip of the probes were 8.0 mm close to a major hepatic vein and absent when >30 mm away. Temperatures (T1 and T2) on either side of the hepatic vein near the tip of the probes, heating probe temperature (T3), outlet perfusate temperature (T4), and ablation time were monitored.With or without heat sink, BP radiofrequency ablated a larger volume and mass, compared with MP RFA or MW ablation, with latter device producing the highest density of tissue ablated. MW ablation produced an ellipsoidal shape while radiofrequency devices produced spheres.Percentage heat sink effect in Bipolar radiofrequency : Mono-polar radiofrequency : Microwave was (Volume) 33:41:22; (mass) 23:56:34; (density) 9.0:26:18; and (relative elipscity) 5.8:12.9:1.3, indicating that BP and MW devices were less affected.Percentage heat sink effect on time (minutes) to reach maximum temperature (W) = 13.28:9.2:29.8; time at maximum temperature (X) is 87:66:16.66; temperature difference (Y) between the thermal probes (T3) and the temperature (T1 + T2)/2 on either side of the hepatic vessel was 100:87:20; and temperature difference between the (T1 + T2)/2 and temperature of outlet circulating solution (T4), Z was 20.33:30.23:37.5.MW and BP radiofrequencies were less affected by heat sink while MP RFA was the most affected. With a single ablation, BP radiofrequency ablated a larger volume and mass regardless of heat sink.     

Anticoagulation Strategies in Patients With Cancer: JACC Review Topic of the Week

Patients with active cancer are at an increased risk of arterial and venous thromboembolism (VTE) and bleeding events. Historically, in patients with cancer, low molecular weight heparins have been preferred for treatment of VTE, whereas warfarin has been the standard anticoagulant for stroke prevention in patients with atrial fibrillation (AF). More recently, direct oral anticoagulants (DOACs) have been demonstrated to reduce the risk of venous and arterial thromboembolism in large randomized clinical trials of patients with VTE and AF, respectively, thus providing an attractive oral dosing option that does not require routine laboratory monitoring. In this review, we summarize available clinical trial data and guideline recommendations, and outline a practical approach to anticoagulation management of VTE and AF in cancer.     

A comparison of pulse oximetry and respiratory rate in patient screening

Objective: To examine how well respiratory rate correlates with arterial oxygen saturation status as measured by pulse oximetry, and determine whether respiratory rate measurements detect oxygen desaturation reliably.Methods: Respiratory rate (RR) and oxygen saturation (SaO₂) were measured prospectively on 12 096 consecutive adult emergency department triage patients at a university medical center. Respiratory rate was measured by counting ausculated breath sounds for 1 min. Pulse oximetry was used to measure SaO₂. Measurements were analysed by age (with one group for 18–19 year olds, groups for every 10 yr from age 20 to age 60, and groups for every 5 yr for subsequent ages). Pearson correlation coefficients were calculated for each age group as well as the weighted average coefficient. Cases having oxygen saturation below 90% were examined to determine how frequently they exhibited increased RR (increased RRs were defined as any rate in the upper five percentile by age.Results: Correlation coefficients ranged from 0·379 to −0·465 with a weighted mean of −0·160. Coefficients for ages 18 through 70 years (representing 10 740 patients) all had magnitude <0·252. Overall, only 33% of subjects with oxygen saturation below 90% exhibited increased RR.Conclusions: Respiratory rate measurements correlate poorly with oxygen saturation measurements and do not screen reliably for desaturation. Patients with low SaO₂ do not usually exhibit increased RR. Similarly, increased RR is unlikely to reflect desaturation.     

Preparations of PAN-based adsorbers for separation of cesium and cobalt from radioactive wastes.

Ion-exchange adsorbers are widely used for radioisotope separation, as well as for the removal of hazardous fission products from aqueous waste prior to discharge to the environment. Inorganic exchangers are of particular interest because of their resistance to radiolytic damage and selectivity for specific fission products. Composite inorganic-organic adsorbers represent a group of inorganic ion exchangers modified by using binding organic material, polyacrylonitrile, for preparation of larger size particles with higher granular strength. At the same time, kinetics of ion exchange and sorption capacity of such composite adsorbers are not influenced by the binding polymer. The contents of active component in composite adsorber were varied over a very broad range of 5-95% of the dry weight of the composite adsorber, and tested for separation and concentration of various stimulated wastes. Three different inorganic sorbents, granular hexacyanoferrate-based ion exchanger, were developed for the removal of Cs and Co ions from waste solutions containing different complexing agents as detergents. Radiation and thermal stability studies show that these adsorbents can be used for medium-active waste treatment.     

Chymopapain chemonucleolysis: correlation of diagnostic radiographic factors and clinical outcome

The therapeutic response to treatment of lumbar disk herniation with chymopapain chemonucleolysis is significantly influenced by the criteria used for patient selection. Although careful clinical selection of patients reduces the frequency of treatment failure, some patients do not achieve satisfactory relief of pain with chemonucleolysis. In an attempt to identify objective pretreatment radiographic findings that might refine selection criteria and further reduce the failure rate of chemonucleolysis, a retrospective correlation of pretreatment radiographs and clinical responses was made of 200 consecutive chemonucleolysis patients. Marked improvement in sciatica occurred in 79.9% and 79.3% of patients at early and late follow-up, respectively. There was a significantly higher response rate, however, in patients who had definite radiographic evidence of focal disk herniation and in those patients with definite radiographic evidence of nerve-root compression (marked nerve-root deviation, nerve-root flattening or edema, root-sleeve amputation) by disk material. Those patients with a preinjection disk height greater than the mean had a slightly better response rate (91.1%) than those whose disk height was smaller than the mean (80.0%). Most cases of treatment failure could be attributed to an incorrect radiographic diagnosis, treatment of patients with equivocal diagnostic studies, the presence of "free" disk fragments, and causes of nerve-root compression unresponsive to chymopapain.     

Discovery and Validation of a Urinary Exosome mRNA Signature for the Diagnosis of Human Kidney Transplant Rejection

BackgroundDeveloping a noninvasive clinical test to accurately diagnose kidney allograft rejection is critical to improve allograft outcomes. Urinary exosomes, tiny vesicles released into the urine that carry parent cells’ proteins and nucleic acids, reflect the biologic function of the parent cells within the kidney, including immune cells. Their stability in urine makes them a potentially powerful tool for liquid biopsy and a noninvasive diagnostic biomarker for kidney-transplant rejection.MethodsUsing 192 of 220 urine samples with matched biopsy samples from 175 patients who underwent a clinically indicated kidney-transplant biopsy, we isolated urinary exosomal mRNAs and developed rejection signatures on the basis of differential gene expression. We used crossvalidation to assess the performance of the signatures on multiple data subsets.ResultsAn exosomal mRNA signature discriminated between biopsy samples from patients with all-cause rejection and those with no rejection, yielding an area under the curve (AUC) of 0.93 (95% CI, 0.87 to 0.98), which is significantly better than the current standard of care (increase in eGFR AUC of 0.57; 95% CI, 0.49 to 0.65). The exosome-based signature’s negative predictive value was 93.3% and its positive predictive value was 86.2%. Using the same approach, we identified an additional gene signature that discriminated patients with T cell–mediated rejection from those with antibody-mediated rejection (with an AUC of 0.87; 95% CI, 0.76 to 0.97). This signature’s negative predictive value was 90.6% and its positive predictive value was 77.8%.ConclusionsOur findings show that mRNA signatures derived from urinary exosomes represent a powerful and noninvasive tool to screen for kidney allograft rejection. This finding has the potential to assist clinicians in therapeutic decision making.     

Variables of movement amplitude and frequency in the development of motion sickness in Suncus murinus.

The aim of the present study was to investigate the effect of different frequency and amplitude of horizontal movements to induce motion sickness and to identify gender differences and adaptation to motion stimulus in adult Suncus murinus. Each animal was subjected to a horizontal motion stimulus of 3, 7, 13, or 40 mm amplitude at a frequency of 0.5, 1, 2, or 3 Hz. The number of vomiting episodes and the latency of onset were recorded over a 10-min period. For the study of adaptation, different groups of males were exposed to repeated motion sickness (using 0.5 or 1 Hz frequency and the amplitude of 40 mm) either every 2 days for a period of 30 days, or once every week for a period of 28 days. In all animals the number of emetic episodes obtained at 1 and 2 Hz were significantly higher by 40-80% than those at 0.5 and 3 Hz using either 13 or 40 mm amplitude of movements; this was followed by shorter latency of emesis. Age-matched females were shown to be more responsive to the emetic stimuli than males as the number of emetic episodes at 1, 2, and 3 Hz (amplitude of 40 mm) were significantly higher by 33%, 42%, and 75%, respectively, than in males; this also was followed by a shorter latency of emetic response. In the study of adaptation, when used once every 2 days, by the second challenge (at 0.5 Hz) the number of emetic episodes was reduced by 62%, and to subsequent challenges emesis was absent or greatly reduced. Also, a reduction in responsiveness was observed at 1 Hz, which attained a maximum effect by the third challenge. The present results indicated that Suncus murinus is sensitive to horizontal motion stimulus, the emetic episodes were significantly greater at 1 and 2 Hz than at either a lower or higher frequency, a repeated challenge once every 2 days but not weekly reduced the number of emetic episodes, and in all experiments, age-matched female animals were more responsive than males to motion stimulus and in some experiments this achieved significance.     

Bilateral synchronous breast cancer: mode of detection and comparison of histologic features between the 2 breasts

BACKGROUND: Bilateral synchronous breast cancer is uncommon (accounting for 1.0%-2.6% of all patients with breast cancer), and most physicians do not accumulate a large personal experience of patients with this disease. We reviewed our experience with patients with bilateral synchronous breast cancer, focusing on the mode of detection and histologic features in the 2 breasts. METHODS: The charts of patients who were treated at this institution for bilateral synchronous breast cancer during the 15-year period of 1984 through 1999 were reviewed. Information regarding age, mode of detection, histopathologic features, treatment, and overall survival were analyzed. RESULTS: During the study period, 51 patients (all women) were treated at our institution for bilateral synchronous breast cancer. This comprised 2.1% of all patients (n = 2382 patients) treated for breast cancer during the same period of time. The first cancer was detected by palpation in 81% and by mammography in 14%. The corresponding figures for the contralateral cancer were 24% and 54%, respectively. The histologic type of cancer was identical in the 2 breasts in 29 patients (57%) and was different between the 2 breasts in 22 patients (43%). The overall 10-year survival rate was 63%. CONCLUSIONS: Bilateral synchronous breast cancer is often detected by mammography and is frequently of the same histologic type as the index cancer. A better awareness of the risk for this disease may help detect bilateral breast cancer earlier.