Microwave Scissors-Based Sutureless Laparoscopic Partial Nephrectomy Versus Conventional Open Partial Nephrectomy in a Porcine Model: Usefulness and Complications.

BACKGROUND: This study aimed to compare the benefits and safety of microwave scissors-based sutureless laparoscopic partial nephrectomy (MSLPN) with those of conventional open partial nephrectomy (cOPN). METHODS: Each kidney in nine pigs underwent MSLPN using microwave scissors (MWS) via transperitoneal laparoscopy or cOPN via retroperitoneal open laparotomy. The kidney's lower and upper poles were resected under temporary hilar-clamping. The renal calyces exposed during renal resections were sealed and transected using MWS in MSLPN and were sutured in cOPN. For MWS, the generator's power output was 60 W. Data on procedure time (PT), ischemic time (IT), blood loss (BL), normal nephron loss (NNL), and extravasation during retrograde pyelogram were compared between the two techniques. RESULTS: The authors successfully performed 22 MSLPNs and 10 cOPNs. Compared with cOPN, MSLPN was associated with significantly lower PT (median, 9.2 vs 13.0 min; p = 0.026), IT (median, 5.9 vs 9.0 min; p < 0.001), BL (median, 14.4 vs 38.3 mL; p = 0.043), and NNL (median, 7.6 vs 9.4 mm; p = 0.004). However, the extravasation rate was higher in the MSLPN group than in the cOPN group (54.5 % [n = 12] vs 30.0 % [n = 3]), albeit without a significant difference (p = 0.265). Pelvic stenosis occurred in one MSLPN procedure that involved deep lower pole resection near the kidney hilum. CONCLUSIONS: The study data show that MSLPN can improve intraoperative outcomes while reducing technical demands for selected patients with non-hilar-localized renal tumors. However, renal calyces, if violated, should be additionally sutured to prevent urine leakage.

Comparison of off-clamp microwave scissors-based sutureless partial nephrectomy versus on-clamp conventional partial nephrectomy in a canine model.

Objectives: To compare the usefulness and safety of off-clamp microwave scissors-based sutureless partial nephrectomy (MSPN) with on-clamp conventional partial nephrectomy (cPN) in dogs. Methods: We performed off-clamp MSPN using microwave scissors (MWS) in six dogs, and on-clamp cPN in three dogs, in two-stage experiments. The bilateral kidney upper poles were resected via a midline incision under general anesthesia. After 14 days of follow-up, the lower pole resections were performed. The renal calyces exposed during renal resections were sealed and transected using MWS in off-clamp MSPN and were sutured in on-clamp cPN. In the off-clamp MSPN group, the generator's power output of MWS was set as either 50 W or 60 W for each kidney side. We compared the procedure time (PT), ischemic time (IT), blood loss (BL), and normal nephron loss (NNL) between the two techniques using the Mann-Whitney U-test. Results: We successfully performed 24 off-clamp MSPNs and 12 on-clamp cPNs. The off-clamp MSPN was significantly superior to on-clamp cPN in avoiding renal ischemia (median IT, 0 min vs. 8.6 min, p < 0.001) and reducing PT (median PT, 5.8 min vs. 11.5 min, p < 0.001) and NNL (median NNL, 5.3 mm vs. 6.0 mm, p = 0.006) with comparable BL (median BL, 20.9 ml vs. 23.2 ml, p = 0.804). No bleeding and major urine leakage were noted during the reoperations. Conclusions: Off-clamp MSPN outperforms on-clamp cPN in lowering the risks of postoperative renal function impairment in dogs.

Feasibility of Microwave Scissors-Based Off-Clamp Laparoscopic Partial Nephrectomy in a Porcine Model.

OBJECTIVES: To assess the feasibility of off-clamp laparoscopic partial nephrectomy using microwave scissors. METHODS: We performed transperitoneal laparoscopic partial nephrectomy, without hilar clamping or renorrhaphy, using only microwave scissors for renal resection in a porcine model. For each kidney, 2 types of procedures were performed: a middle pole resection excising an area of 2-cm diameter and approximately 1-cm depth and a lower pole resection at the level of the lower polar line. The renal calyces exposed during renal resection were sealed and transected using microwave scissors. After 3 days of follow-up, the pigs were reoperated to inspect for postoperative complications. Euthanasia was performed to collect the remaining kidneys for histopathological examination. RESULTS: Ten procedures were successfully performed, without hilar clamping or suturing of the renal calyces and parenchyma, in 5 kidneys from 3 pigs. The median resecting time, blood loss, and lateral thermal injury were 23.2 min, 47.1 mL, and 6.8 mm in the middle pole resection, and were 15.1 min, 26.5 mL, and 6.9 mm in the lower pole resection, respectively. No complications were noted during reoperation, such as postoperative hemorrhage and major urine leakage. Extravasation occurred in 2 middle pole resections and 3 lower pole resections during retrograde pyelogram. Hematoxylin and eosin staining revealed thermal injury characterized by tissue microwave fixation in the near zone and acute coagulative necrosis in the intermediate zone. CONCLUSIONS: Microwave scissors-based off-clamp laparoscopic partial nephrectomy is feasible in pigs and can be used for clinical applications.

Flexible ureteroscope capable of acute-angled and balanced omnidirectional bending based on soft and flexible porous tube and crossed control wiring.

Flexible ureteroscopes (fURSs) have performance limitations in accessing acute-angled calyxes and omnidirectional bending. We propose and develop a fURS based on a soft and flexible porous tube and crossed control wiring to overcome these limitations. The fURS prototype comprises a flexible solid polyamide-12 tube and a stretch-retractable expanded polytetrafluoroethylene distal tube with 40% porosity connected by a unique cylindrical wire-routing hook (CWH). The series tube includes four crossed but not contacting loop-formed control wires to provide balanced omnidirectional bending and optimized distal tube bending performance. Bending performance was assessed compared with a conventional fURS, and feasibility studies were performed using a renal phantom. The prototype achieved a 275° omnidirectional maximum bend angle by combining up-down and right-left directions. The bent shape was more compact than the conventional fURS. Thus, the prototype achieved approximately a 1.6-fold larger maximal active bending angle within the restricted environment and a 5.5-fold larger passive bending angle. The crossed control wiring design reduced CWH offset distance by about 75% compared with conventional straight wire routing. The prototype exhibited considerably improved steering performance, exemplified by its ability to access an acutely angled calyx. Our design could improve treatment outcomes and shorten operation times associated with calyceal stone removal.

Steerable catheter based on wire-driven seamless artificial blood vessel tube for endoscopic retrograde transpapillary interventions.

PURPOSE: Current steerable catheters (SCs) for endoscopic retrograde cholangiopancreatography (ERCP) have performance limitations caused by an asymmetric multiple-slit tube design with a small maximum bend angle, lesser curvatures, and insufficient durability. We propose a wire-driven SC for balanced bidirectional bending using artificial blood vessel material to overcome these limitations. We assess the SC prototype's steerability using phantom and animal models. METHODS: The SC prototype employed a slit-less and multiple-lumen seamless tube with a polytetrafluoroethylene (PTFE) body with stretch-retractable porous expanded PTFE at the distal end, and loop-formed control wires. We evaluated the wire routing design using a static model. The bending performance was compared with conventional SCs. Feasibility studies were performed, including major duodenal papilla insertions and ductal branch selections in desktop phantoms and a mini-pig model. RESULTS: The proposed design reduced the wire contact force by 48% compared to the single wire configuration. The maximum bend angle was 162°, almost twofold larger than that for conventional SCs. The lateral tip position in the bent shape was maximally 56% smaller. The tip flexibility was comparable to conventional SCs, and the insertion resistance was similar to the passive catheters. Phantom studies showed that the SC prototype could perform the large and protuberant papilla insertions and fine ductal branch selections without breaking; the animal study was completed successfully. CONCLUSION: We propose a wire-driven SC design for ERCP using a multi-lumen seamless tube and two loop-formed control wires, different from the conventional SC design with a multiple-slit tube and single control wire. The SC prototype records balanced bidirectional bending with a maximum bending angle of ± 162° without breakage risk. The phantom and animal studies show that the prototype performance potentially facilitates papilla cannulations and intrahepatic ductal branch seeking.

Occupational therapy using a robotic-assisted glove ameliorates finger dexterity and modulates functional connectivity in amyotrophic lateral sclerosis.

INTRODUCTION: Although rehabilitation is recommended for amyotrophic lateral sclerosis (ALS), improvement of functional decline has hardly been achieved. We investigated the effect of occupational therapy that uses a robotic-assisted glove (RAG) on hand dexterity and the functional connectivities found in the brain of ALS patients. METHOD: Ten patients diagnosed with ALS and admitted to the Shiga University of Medical Science (SUMS) Hospital from December 2018 to December 2021 participated in the study. These participants chose the hand side to wear RAG and exercised for two weeks. A sham movement was performed on the other side. We administered several functional assessments, including the Simple Test for Evaluating Hand Function (STEF), grip strength, pinch meter for grip strength, Canadian occupational performance measure (COPM), as well as nerve conduction study (NCS) before and after the exercise, and evaluated the results. We also analyzed six patients' resting-state functional magnetic resonance imaging (rs-fMRI). RESULTS: Two-week robotic rehabilitation improved the STEF, grip strength, and COPM scores when compared with those of the other side. However, no significant effect was observed in the pinch meter and the NCS results. The rs-fMRI data analysis revealed that the robotic rehabilitation augmented two functional connectivities between the left pallidum-right supplementary motor cortex and right insular cortex-right sensorimotor network among the patients, which had beneficial effects. CONCLUSION: The occupational therapy using RAG displayed improved hand dexterity. The enhanced functional connectivities around the sensorimotor network might be associated with the improvement in hand dexterity because of the RAG.

Needle Tip Detection Using Ultrasound Probe for Vertical Punctures: A Simulation and Experimental Study.

Current ultrasound-guided punctures are difficult to perform as they are performed at an angle to the ultrasound image of the affected area, resulting in longer puncture times, lower success rates, and higher unexpected injury rates. Vertical puncture techniques have also been investigated, but the principle of needle tip detection remains unclear. To optimize ultrasound probes for puncture, the principle of needle tip detection should be understood. This study aimed to verify the principle of needle tip detection and optimal measurement conditions for vertical puncture. Needle tip detection was performed in animal experiments using a probe with a central puncture slit. Moreover, the needle tip was detected at short distances using a puncture spacer. We also investigated the signal from the needle tip using a ring probe and confirmed the principle of needle tip detection, effect of needle tip angle, and insertion depth on needle tip detection through simulation and experiments. Needle tip detection using ultrasound-guided waves was described, and the relationship among needle tip angle, detection intensity, and phase change was verified. The needle tip can be detected by the leakage of the ultrasound-guided wave generated inside the needle tip.

Feasibility of Microwave-Based Scissors and Tweezers in Partial Hepatectomy: An Initial Assessment on Canine Model.

Purpose: This study aimed to assess the feasibility of partial hepatectomy (PH) simplified by using microwave-based devices in animal experiments. Methods: PH was performed on 16 beagles using either Acrosurg Scissors (AS) or Acrosurg Tweezers (AT) without hepatic pedicle (HP) control. Parenchymal transection time, Glissonean pedicle (GP) seal time, bleeding volume, bile leak, and burst pressure were recorded. Probable complications were investigated after 4 weeks. Results: Transection time (6.5 [6.0-7.6] vs. 11.8 [10.5-20.2] min, p < 0.001) with AT were significantly shorter than with AS. GP sealing times (60 [55-60] vs. 57 [46-91] s, p = 0.859) by both devices were nearly similar. Bleeding volume in the AT group was approximately one-fourth of that in the AS group (6.7 [1.4-22] vs. 28.8 [5.8-48] mL, p = 0.247). AT created higher burst pressure on the bile duct stumps (p = 0.0161). The two devices did not differ significantly in morbidity and mortality after four-week follow-up. Conclusion: Acrosurg devices achieved a safe PH without HP control owing to microwave-based sealing. AS could be used alone in PH, whereas the clamp-crushing function of AT seemed more advantageous in reducing the transection time and blood loss.

Correlations between cardiovascular parameters and image parameters on dynamic chest radiographs in a porcine model under fluid loading.

Latest digital radiographic technology permits dynamic chest radiography during the cardiac beating and/or respiration, which allows for real-time observation of the lungs. This study aimed to assess the capacity of dynamic flat-panel detector (FPD) imaging without the use of contrast media to estimate cardiovascular parameters based on image parameters of a porcine model under fluid loading. Three domestic pigs were intubated, and mechanical ventilation was provided using a ventilator under anesthesia. A porcine model involving circulatory changes induced by fluid loading (fluid infusion/blood removal) was developed. Sequential chest radiographs of the pigs were obtained using a dynamic FPD system within the first 5 min after fluid loading. Image parameters such as the size of the heart shadow and mean pixel values in the lungs were measured, and correlations between fluid loading and cardiovascular parameters (blood pressure [BP], cardiac output [CO], central venous pressure [CVP], and pulmonary arterial pressure [PAP]) were analyzed based on freedom-adjusted coefficients of determination (Rf2). Fluid loading was correlated with radiographic lung density and the size of the heart shadow. Radiographic lung density was correlated with the left and right heart system-related parameters BP, CO, CVP, and PAP. The size of the heart shadow correlated with the left heart system-related parameters CO and BP. Dynamic FPD imaging allows for the relative evaluation of cardiovascular parameters based on image parameters. This diagnostic method provides radiographic image information and estimates relative circulatory parameters.

Functional Evaluation of a Novel Microwave Surgical Device in a Canine Splenectomy Model.

Aim: Partial splenectomy remains a difficult procedure even with the assistance of a sealing system. Recently, a scissor-like microwave energy device (Acrosurg) that provides seamless coagulation and manual cutting has been applied in surgery. The objective of this study is to evaluate the surgical capabilities of Acrosurg in partial splenectomy. Materials and Methods: Acrosurg and Harmonic Focus (HF) were employed for partial splenectomy in dogs without prior ligation of vessels. Cutting time, cutting area, and bleeding were recorded. Lateral thermal injury (LTI), possible complications was observed immediately and after 4 weeks. Results: The manual cutting mechanism of Acrosurg required a longer cutting time compared with the automatic cutting mode of HF (301.5 [243.2-527] vs. 114.5 [106.0-135.0] sec, p < 0.01). There was no statistical difference in cutting area or bleeding cases. Acrosurg achieved complete hemostasis in all cases, whereas the HF group failed to stop bleeding in two of the eight cases. The Acrosurg group exhibited a similar LTI compared with the HF group (3.0 [2.4-3.4] vs. 2.7 [2.3-2.9] mm, p = 0.151), but the LTI of the Acrosurg group tended to shrink more after 4 weeks (1.2 [1.0-1.3] vs. 1.7 [1.3-1.9] mm, p < 0.05). Conclusions: A microwave energy device enabled a partial splenectomy without vessel ligation. The combination of manual cutting and sealing capability helps not only provide an appropriate seal time by adjusting cutting timing adaptively but also potentially stop bleeding by using a microwave heating process unlike other energy devices.

Involvement of TRPV1-containing peripheral sensory efferents in hemodynamic responses in a rat hemorrhagic shock model.

BACKGROUND: Mechanisms underlying hemodynamic disturbance in hemorrhagic shock are not completely understood. Transient receptor potential vanilloid 1-expressing afferents are involved in hemorrhagic shock pathology, and transient receptor potential vanilloid 1 antagonist, capsazepine, acts on the central nervous system to improve mortality in a rat hemorrhagic shock model. In contrast, transient receptor potential vanilloid 1-positive efferents promote vasoactive reactions through the release of neuropeptides, including calcitonin gene-related peptides. This study aimed to investigate whether transient receptor potential vanilloid 1-positive peripheral sensory efferents are involved in hemodynamic responses after hemorrhagic shock. METHODS: Male rats underwent hemorrhagic shock (mean arterial pressure 30 mm Hg for 90 min, followed by resuscitation for 30 min) and received capsazepine (5 µM/kg) 30 min after shock induction. A separate cohort of rats subjected to hemorrhagic shock received hCGRP8-37 (300 µg/kg), a calcitonin gene-related peptide receptor antagonist, at 30, 60, or 90 minutes after shock induction. The 24-hour survival rate, mean arterial pressure, heart rate, arterial blood gas, and plasma calcitonin gene-related peptide levels were measured. Tissue blood flow and oxygenation both in the mesentery and skeletal muscle were also assessed. RESULTS: Capsazepine treatment prevented the hemorrhagic shock-induced increase in plasma calcitonin gene-related peptide levels, and hCGRP8-37 treatment improved the 24-h survival rates after hemorrhagic shock at a time-dependent manner. The hCGRP8-37- or capsazepine-treated rats exhibited tissue oxygenation and metabolic conditions comparable to those in control rats at the end of the experiment. CONCLUSION: Transient receptor potential vanilloid 1 plays a crucial role in hemodynamic responses to hemorrhagic shock, partly via calcitonin gene-related peptide release, involved in its peripheral sensory-efferent functions. The hCGRP8-37 appears to improve peripheral circulatory failure, which may be useful as adjunct treatment after hemorrhagic shock.

Vessel-Sealing Capability of Novel Microwave Sealer: Experimental Study in Animal Models.

Background. Ultrasonically activated dissectors (UADs) and radiofrequency-based devices have been considered excellent surgical devices because of their reliability and flexibility. Meanwhile, microwave-based devices have demonstrated potential with their unique heating mechanism. This study aims to compare the sealing function of a newly invented forceps-like microwave sealer (MS) with that of currently available UADs. Materials and Methods. MS and 2 examples of UADs (Harmonic Focus+ [HF+] and Sonicision [SNC]) were employed to perform mesenterectomies (in vivo) and sealing sizable vessels (ex vivo). Vessel diameter, seal time, burst pressure (BP), sealing completion, and instrument sticking were recorded. The samples underwent histological investigation for thermal damage evaluation. Results. During mesenterectomies, MS required 3 seconds and 30 W to secure a complete seal. The BP achieved by the MS seal was higher than that of HF+ and SNC on arteries (851 ± 203.7 vs 682.4 ± 287.3, P < .05; vs 833.1 ± 251.2 mmHg, P = .4523, respectively) but was not statistically different on veins (324.9 ± 203.5 vs 460.1 ± 320.3 vs 508.3 ± 350.7 mmHg, P = .215). In all trials, MS caused less sticking but exhibited similar heat-induced alterations to UADs. MS's thermal spread was not statistically more extended than that of UADs on either arteries or veins. Conclusions. MS was capable of not only sealing tiny vessels but also achieving high-pressure endurance on sizable vessels. Its forceful grasping and synchronous heating process helped create solid stumps with an acceptable thermal spread.

Magnetic resonance and ultrasound image-guided navigation system using a needle manipulator.

PURPOSE: Image guidance is crucial for percutaneous tumor ablations, enabling accurate needle-like applicator placement into target tumors while avoiding tissues that are sensitive to injury and/or correcting needle deflection. Although ultrasound (US) is widely used for image guidance, magnetic resonance (MR) is preferable due to its superior soft tissue contrast. The objective of this study was to develop and evaluate an MR and US multi-modal image-guided navigation system with a needle manipulator to enable US-guided applicator placement during MR imaging (MRI)-guided percutaneous tumor ablation. METHODS: The MRI-compatible needle manipulator with US probe was installed adjacent to a 3 Tesla MRI scanner patient table. Coordinate systems for the MR image, patient table, manipulator, and US probe were all registered using an optical tracking sensor. The patient was initially scanned in the MRI scanner bore for planning and then moved outside the bore for treatment. Needle insertion was guided by real-time US imaging fused with the reformatted static MR image to enhance soft tissue contrast. Feasibility, targeting accuracy, and MR compatibility of the system were evaluated using a bovine liver and agar phantoms. RESULTS: Targeting error for 50 needle insertions was 1.6 ± 0.6 mm (mean ± standard deviation). The experiment confirmed that fused MR and US images provided real-time needle localization against static MR images with soft tissue contrast. CONCLUSIONS: The proposed MR and US multi-modal image-guided navigation system using a needle manipulator enabled accurate needle insertion by taking advantage of static MR and real-time US images simultaneously. Real-time visualization helped determine needle depth, tissue monitoring surrounding the needle path, target organ shifts, and needle deviation from the path.

Anti-endotoxin Properties of Polymyxin B-immobilized Fibers.

Polymyxin B is an antibiotic that shows strong bactericidal activity against Gram-negative bacteria, by binding to and inactivating endotoxin. Systemic administration of polymyxin B in humans is restricted because of its nephrotoxicity and neurotoxicity, and this compound was therefore considered a strong candidate ligand for the extracorporeal selective adsorption of circulating endotoxin in the blood. Toraymyxin® is a direct hemoperfusion column that uses polymyxin B attached to an insoluble carrier to bind endotoxin in the blood. In 1994, the Japanese National Health Insurance system approved the use of Toraymyxin for the treatment of endotoxemia and septic shock.In this chapter, we will review the development, clinical use, and efficacy of Toraymyxin, examine the structure of the Toraymyxin column, and comment on the current position of Toraymyxin in the treatment of severe sepsis and septic shock. We will also highlight some potential new applications of Toraymyxin for pulmonary diseases.

Detection of Pulmonary Embolism Based on Reduced Changes in Radiographic Lung Density During Cardiac Beating Using Dynamic Flat-panel Detector: An Animal-based Study.

RATIONALE AND OBJECTIVES: To assess the capacity of dynamic flat-panel detector imaging without the use of contrast media to detect pulmonary embolism (PE) based on temporal changes in radiographic lung density during cardiac beating. MATERIALS AND METHODS: Sequential chest radiographs of six pigs were acquired using a dynamic flat-panel detector system. A porcine model of PE was developed, and temporal changes in pixel values in the imaged lungs were analyzed during a whole cardiac cycle. Mean differences in temporal changes in pixel values between affected and unaffected lobes were assessed using the paired t test. To facilitate visual evaluation, temporal changes in pixel values were depicted using a colorimetric scale and were compared to the findings of contrast-enhanced images. RESULTS: Affected lobes exhibited a mean reduction of 49.6% in temporal changes in pixel values compared to unaffected lobes within the same animals, and a mean reduction of 41.3% compared to that before vessel blockage in the same lobe. All unaffected lobes exhibited significantly-increased changes in pixel values after vessel blockage (p < 0.01). In all PE models, there were color-deficient areas with shapes and locations that matched well with the perfusion defects confirmed in the corresponding contrast-enhanced images. CONCLUSION: Dynamic chest radiography enables the detection of perfusion defects in the lobe unit based on temporal changes in image density, even without the use of contrast media. Quantification and visualization techniques provide a better understanding of the circulation-induced changes depicted in dynamic chest radiographs.

The invention of microwave surgical scissors for seamless coagulation and cutting.

PURPOSE: We developed a microwave energy-based scissors device (MWCX) that is capable of performing cutting and coagulation using 2.45 GHz microwave energy. This paper aims to present the concept of the device and assess the basic functions including the hemostasis, cutting, and sealing abilities. METHODS: Seven beagle dogs were used in our experiments. In six dogs, we measured the coagulation time (CT), lateral thermal injury (LTI), bursting pressure (BP). The dogs were then subjected to re-laparotomy 1 week later to allow us to investigate the results. In one dog, the same factors and the quantities of smoke and mist emitted were compared to those observed when using a Harmonic Focus (HF) device. RESULTS: At 60 W, the MWCX could cut and seal small (5 s, diameter 1-2 mm) and medium-sized (10 s, 3-4 mm) vessels with complete hemostasis. The liver (length 2 cm) was cut for 30 s. Harvested vessels were sealed for 10 s (artery, 17 times; vein, six times). The mean BP was 887. 8 ± 41.5 mmHg in the medium arteries and 457.2 ± 118.0 mmHg in veins, with a mean diameter of 4.5 ± 1.3 mm. In a comparative study, the MWCX showed similar results to the HF with regard to the CT, BP and LTI, and emitted less smoke and mist. CONCLUSION: The MWCX showed similar levels of functionality and safety to HF, as well as the advantages offered by the use of microwave energy. Microwave devices might be used in the majority of applications for which traditional energy devices are used.

Pulmonary Function Diagnosis Based on Respiratory Changes in Lung Density With Dynamic Flat-Panel Detector Imaging: An Animal-Based Study.

OBJECTIVES: The aims of this study were to address the relationship between respiratory changes in image density of the lungs and tidal volume, to compare the changes between affected and unaffected lobes, and to apply this new technique to the diagnosis of atelectasis. MATERIALS AND METHODS: Our animal care committee approved this prospective animal study. Sequential chest radiographs of 4 pigs were obtained under respiratory control with a ventilator using a dynamic flat-panel detector system. Porcine models of atelectasis were developed, and the correlation between the tidal volume and changes in pixel values measured in the lungs were analyzed. The mean difference in respiratory changes in pixel values between both lungs was tested using paired t tests. To facilitate visual evaluation, respiratory changes in pixel values were visualized in the form of a color display, that is, as changes in color scale. RESULTS: Average pixel values in the lung regions changed according to forced respiration. High linearity was observed between changes in pixel values and tidal volume in the normal models (r = 0.99). Areas of atelectasis displayed significantly reduced changes in pixel values (P < 0.05). Of all atelectasis models with air trapping and air inflow restriction, 92.7% (19/20) were visualized as color-defective or color-marked areas on functional images, respectively. CONCLUSION: Dynamic chest radiography allows for the relative evaluation of tidal volume, the detection of ventilation defects in the lobe unit, and a differential diagnosis between air trapping and air inflow restriction, based on respiratory changes in image density of the lungs, even without the use of contrast media.

5-fluorouracil combined with cisplatin and mitomycin C as an optimized regimen for hyperthermic intraperitoneal chemotherapy in gastric cancer.

BACKGROUND AND OBJECTIVES: Optimized drug regimens for hyperthermic intraperitoneal chemotherapy (HIPEC) have not been standardized completely in patients with advanced gastric cancer (GC). We evaluated an optimized anti-tumor protocol comprising 5-fluorouracil (5-FU) combined with cisplatin (CDDP) and mitomycin C (MMC) in vitro for clinical use of HIPEC. METHODS: The sensitivities of 5-FU, CDDP, or MMC, alone or in combination, using different drug concentrations, exposure times, and hyperthermic conditions (42°C) were determined in vitro by the CD-DST method using 3 different differentiated GC cell lines. RESULTS: The tumor cell growth-inhibitory effect of 5-FU was concentration-dependent for all cell lines. In addition, 5-FU showed a hyperthermic sensitization effect at all drug concentrations for all cell lines. The appropriate concentration of each drug was 5-FU, 200 µg/mL; CDDP, 10 µg/mL; MMC, 2 µg/mL. Under hyperthermic conditions, most growth-inhibitory effects for each drug at 30 min was equivalent to 60 min of exposure; use of three drugs combined significantly inhibited growth compared with any of the drugs alone. CONCLUSION: An appropriate in vitro intraperitoneal chemotherapy regimen for GC was combined use of 5-FU, CDDP, and MMC at 42°C for 30 min.