MAP-based kinetic analysis for voxel-by-voxel compartment model estimation: Detailed imaging of the cerebral glucose metabolism using FDG

We propose a novel algorithm for voxel-by-voxel compartment model analysis based on a maximum a posteriori (MAP) algorithm. Voxel-by-voxel compartment model analysis can derive functional images of living tissues, but it suffers from high noise statistics in voxel-based PET data and extended calculation times. We initially set up a feature space of the target radiopharmaceutical composed of a measured plasma time activity curve and a set of compartment model parameters, and measured the noise distribution of the PET data. The dynamic PET data were projected onto the feature space, and then clustered using the Mahalanobis distance. Our method was validated using simulation studies, and compared with ROI-based ordinary kinetic analysis for FDG. The parametric images exhibited an acceptable linear relation with the simulations and the ROI-based results, and the calculation time took about 10 min. We therefore concluded that our proposed MAP-based algorithm is practical.

Expression of thymidine phosphorylase as an effect prediction factor for uterine cervical squamous cell carcinoma after radiotherapy: an immunohistochemical study

Prognoses in cases of uterine cervical squamous cell carcinoma treated with radiotherapy were investigated in association with immunohistochemical expression of an angiogenic factor, thymidine phosphorylase (TP). Forty-six cases of uterine cervical squamous cell carcinoma mainly treated with radiotherapy during 1992–2001 at our clinic were studied. All were diagnosed as stages IIB to IVA. Paraffin-embedded biopsy specimens excised before radiotherapy were stained immunohistochemically using anti-TP monoclonal antibody. The extent of staining in both tumor and interstitial cells was graded as (−), (±), (+), and (2+). Specimens with TP expression levels of (2+) and (+) were regarded as positively stained and those with TP expression levels of (±) and (−) as negatively stained. The efficacy of radiotherapy in both groups was analyzed by the Kaplan–Meier method. With tumor cells, 5-year survival rates for the positive (n = 38) and negative (n = 8) staining groups were 73.9% and 42.9%, respectively; the rate being significantly higher for the TP-positive group (log rank, P = 0.0096). Contrarily, with staining for interstitial cells, the 5-year survival rates for the positive (n = 20) and negative (n = 26) staining groups were 74.1% and 64.6%, respectively, with no significant difference (log rank, P = 0.406). The efficacy of radiotherapy in the group with positive staining of tumor cells was significantly better than in the negative staining group. Immunohistochemical expression of TP in tumor cells is suggested as a useful prognostic factor for uterine cervical squamous cell carcinomas treated with radiotherapy. Choosing therapy for individual cases by referring to factors including TP expression should contribute to an improved prognosis.

Complete extirpation of a bronchogenic cyst causing recurrent laryngeal nerve palsy by thoracoscopy: report of a case

We excised a bronchogenic cyst causing recurrent laryngeal nerve palsy using thoracoscopic surgery. A 28-year-old woman presented after the sudden onset of hoarseness, and laryngoscopic examination showed left vocal cord palsy. Computed tomography and magnetic resonance imaging showed a cystic mass, 4 cm in diameter, in the aortopulmonary window. Thoracoscopic examination revealed that the mass was adhered to the recurrent laryngeal nerve below the aortic arch. We extirpated the cyst via thoracoscopy without any injury to the nerves or major blood vessels. This case illustrates the benefits of thoracoscopic surgery for providing good visualization of the perineural structures and as a safe surgical treatment for a cystic mass in the aortopulmonary window.

Laparoscopically assisted distal gastrectomy with standard radical lymph node dissection for gastric cancer

BACKGROUND

Laparoscopically assisted distal gastrectomy (LADG) with limited lymph node dissection (D1+alpha) has been used to treat a subset of patients with early gastric cancer. Technical advances have expanded indications for LADG to more advanced gastric cancers. However, little data are available on the feasibility or advantages of LADG with standard radical D2 lymph node dissection for patients with gastric cancer.

METHODS

This study reviewed the clinical features of 37 patients who underwent LADG with D2 lymph node dissection for preoperatively diagnosed gastric carcinoma, then compared the results with the features of 31 patients who underwent conventional open distal gastrectomy (ODG) with D2 lymph node dissection.

RESULTS

The laparoscopic procedure was not converted to laparotomy in any patient. There was no operative mortality and no serious morbidity among the patients who underwent LADG with D2 lymph node dissection. As compared with the ODG group, the LADG group had less operative blood loss (p < 0.001), earlier recovery of bowel activity (p = 0.012), and a shorter duration of fever after surgery (p = 0.015), despite the longer operation time (p = 0.007).

CONCLUSIONS

According to this study, LADG with D2 lymph node dissection is feasible and provides several advantages similar to those of limited lymph node dissection (D1+alpha). Depending on surgeons' technical proficiency, LADG can be used with standard radical lymph node dissection for patients with gastric cancers.

[Partial anomalous pulmonary venous drainage to the high superior vena cava; repair by direct anastomosis between the superior vena cava and the right atrial appendage; report of a case]

A 10-year-old boy with partial anomalous pulmonary venous connection to the high superior vena cava (SVC) underwent surgical repair by Williams method. The SVC was divided above the orifice of the anomalous pulmonary vein. The proximal end of the SVC was closed and the distal end of the SVC was anastomosed to the right atrial appendage (RAA). The anomalous pulmonary vein was rerouted to the left atrium via the SVC and the surgically enlarged central type atrial septal defect (ASD). The postoperative course was uneventful except transient sinus bradycardia and catheter study showed no stenosis of the SVC and the RAA.

Sphere-filled organ model for virtual surgery system

We have been developing a virtual surgery system that is capable of simulating surgical maneuvers on elastic organs. In order to perform such maneuvers, we have created a deformable organ model using a sphere-filled method instead of the finite element method. This model is suited for real-time simulation and quantitative deformation. Furthermore, we have equipped this model with a sense of touch and a sense of force by connecting it to a force feedback device. However, in the initial stage the model became problematic when faced with complicated incisions. Therefore, we modified this model by developing an algorithm for organ deformation that performs various, complicated incisions while taking into account the effect of gravity. As a result, the sphere-filled model allowed our system to respond to various incisions that deform the organ. Thus, various physical manipulations that involve pressing, pinching, or incising an organ's surface can be performed. Furthermore, the deformation of the internal organ structures and changes in organ vasculature can be observed via the internal spheres' behavior.

Infrasternal mediastinoscopic surgery for anterior mediastinal masses

BACKGROUND

Infrasternal mediastinoscopic surgery is a new alternative to the thoracoscopic approach for patients with anterior mediastinal masses.

METHODS

We applied this technique to 18 thymectomies, one thymomectomy, and one cystectomy in a total of 20 patients with anterior mediastinal masses and then assessed the surgical results.

RESULTS

Infrasternal mediastinoscopic surgery was accomplished in 18 of the 20 patients (90%). The pathological diagnoses included 13 Masaoka stage I thymomas, one stage II thymoma, two stage III thymomas, one thymic cyst, one pericardial cyst, one thymic granuloma, and one mature teratoma. Two patients with stage III thymoma required conversion to sternotomy, one for invasion into the innominate vein and the other for invasion into the pericardium. There was no surgically related mortality or complications in any patients.

CONCLUSION

Infrasternal mediastinoscopic surgery is safe and feasible for stage I thymoma and other benign tumors in the anterior mediastinum.

Detection of Reovirus type 3 by use of fluorogenic nuclease reverse transcriptase polymerase chain reaction

Reovirus type 3 (Reo-3) can infect numerous rodent species and induces the clinical syndrome 'oily skin disease' in neonatal mice, and is a common contaminant of biological materials. The reverse transcriptase polymerase chain reaction (RT-PCR) assay has proven useful for the detection of Reo-3 in rodents and contaminated biological materials. Fluorogenic nuclease reverse transcriptase polymerase chain reaction assays (fnRT-PCR) combine RT-PCR with an internal fluorogenic hybridization probe, thereby potentially enhancing specificity and eliminating post-PCR processing. Therefore, an fnRT-PCR assay specific for Reo-3 was developed by targeting primer and probe sequences to a unique region of the Reo-3 M3 gene. The fnRT-PCR detected both strains of Reo-3 (Dearing and Abney), but did not detect Reovirus types 1 or 2, other viruses in the family Reoviridae, or other RNA viruses that naturally infect rodents. The fnRT-PCR detected less than 1 fg of target template and detected viral RNA in tissues obtained from mice experimentally infected with Reo-3. The assay also displayed comparable sensitivity when compared to the mouse antibody production test commonly used to detect viral contamination of biological materials. In conclusion, this fnRT-PCR assay offers a potentially high-throughput diagnostic assay for detecting Reo-3 RNA in infected mice and contaminated biological materials.

Interferon-gamma suppresses transforming growth factor-beta-induced invasion of gastric carcinoma cells through cross-talk of Smad pathway in a three-dimensional culture model

We reconstituted a three-dimensional gastric carcinoma model similar to invasive gastric carcinoma tissue. This model consists of a human gastric carcinoma cell line, GCTM-1, a human fibroblast cell line, TIG-1-20, and transforming growth factor-beta (TGF-beta)-containing type I collagen gel. Using this model, we were able to observe the growth of the two cell types, especially carcinoma cell invasive growth, in real time for more than 30 days. TGF-beta and TIG-1-20 were essential for GCTM-1 invasive growth and proliferation, respectively. TGF-beta induced the enhanced expression of matrix metalloproteinase 9 (MMP9) and urokinase-type plasminogen activator (uPA) in GCTM-1 at both the protein and enzymatic activity levels. The TGF-beta-induced invasion of GCTM-1 was inhibited by MMP9- or uPA-antisense (AS) oligonucleotide transfection to GCTM-1. When exogenous interferon-gamma (IFN-gamma) was added to this model, TGF-beta-dependent GCTM-1 invasion was significantly inhibited, concomitant with the decreased expression of MMP9 and uPA. The intracellular signal transduction of Smad was examined to analyse the mechanism of the inhibitory effect of IFN-gamma. TGF-beta accelerated the phosphorylation of Smad2/3 and nuclear translocation of the Smad2/3-Smad4 complex in GCTM-1, but these TGF-beta-induced effects were significantly inhibited by IFN-gamma-induced Smad7 expression. When GCTM-1 was cotransfected with AS oligonucleotide of Smad2 and Smad3, the TGF-beta-induced invasion of GCTM-1 disappeared. In addition, the inhibitory effect of IFN-gamma on TGF-beta-dependent GCTM-1 invasion vanished by the AS oligonucleotide of Smad7 transfection. These results indicate that IFN-gamma inhibits TGF-beta-dependent GCTM-1 invasion through cross-talk in the Smad pathway. IFN-gamma may be a new therapeutic tool for TGF-beta-expressed invasive carcinomas.

Laparoscopic gastric surgery in a Japanese institution: analysis of the initial 100 procedures

BACKGROUND

Although endoscopic surgical procedures are popular in various fields, reports on its use in gastric surgical procedures are limited. This study was designed to review our initial experience with laparoscopic gastric surgical techniques to evaluate indications and surgical results.

STUDY DESIGN

We undertook a retrospective analysis of 100 patients (66 men and 34 women, mean age 63 years) who underwent laparoscopic gastric surgical procedures between 1995 and 2001. Procedures performed were distal gastrectomy (n = 76), wedge resection (n = 20), and intragastric surgical procedures (n = 4). Patients were divided into two groups according to the date of the procedure, from the earliest to the most recent.

RESULTS

There were 85 patients with gastric cancers, 14 submucosal tumors, and 1 duodenal ulcer. In 8 cases conversion was made to an open surgical procedure. Operation times required for distal gastrectomy, wedge resection, and intragastric surgical procedures were 330 +/- 69, 144 +/- 34, and 298 +/- 106 min, and blood loss was 354 +/- 251, 56 +/- 94, and 33 +/- 58 g, respectively. Complications included transient anastomotic stenosis (n = 5), leakage (n = 4), and bleeding (n = 1) after distal gastrectomy, and bleeding (n = 1) after intragastric surgical procedures. There were no complications after wedge resection. Comparing the first and second halves of the series, the percentage of distal gastrectomy significantly increased from 66% to 86% (p = 0.02) and the number of dissected lymph nodes at this procedure increased from 20 +/- 13 to 33 +/- 17 (p < 0.01).

CONCLUSIONS

Laparoscopic gastric surgical procedures are safe and feasible for early gastric cancers and submucosal tumors. Technical advances in lymph node dissection have made distal gastrectomy a leading and increasingly popular laparoscopic procedure for early gastric cancer.

Inhibition of interferon-gamma-activated nuclear factor-kappa B by cyclosporin A: A possible mechanism for synergistic induction of apoptosis by interferon-gamma and cyclosporin A in gastric carcinoma cells

We previously reported synergistic induction of apoptosis by IFN-gamma plus either cyclosporin A (CsA) or tacrolimus (FK506) in gastric carcinoma cells. In this study, we aimed to elucidate the mechanism for this synergistic induction of apoptosis. IFN-gamma plus CsA synergistically induced caspase-3 mediated apoptosis in gastric carcinoma cells. Although IFN-gamma induced activation of signal transducer and activator of transcription1 (STAT1) and expression of interferon regulatory factor-1 (IRF-1) mRNA, IFN-gamma alone was not able to induce caspase-3 activation and apoptosis. When gastric carcinoma cells were treated with cyclohexamide, a protein synthesis inhibitor, following IFN-gamma pretreatment, caspase-3 was activated, and apoptosis was markedly induced. These findings suggest the existence of IFN-gamma-induced anti-apoptotic pathway and we evaluated the effect of IFN-gamma and CsA on calcium-sensitive nuclear factor-kappa B (NF-kappa B) activation. IFN-gamma increased intracellular calcium ion concentration ([Ca(2+)](i)) consisting of a spike and a sustained phase, and the latter was completely abrogated by CsA. Activation of NF-kappa B occurred in response to IFN-gamma, and which was markedly inhibited by either CsA or FK506. NF-kappa B decoy also enhanced the cytotoxic effect of IFN-gamma. These results suggest that IFN-gamma may simultaneously induce the STAT1-mediated apoptotic pathway and the anti-apoptotic pathway through calcium-activated NF-kappa B and that inhibition of the latter by CsA may result in dominance of the apoptosis-inducing pathway.

Dynamic deformation of elastic organ model and the VR cockpit for virtual surgery and tele-surgery

This paper describes a deformable organ model suited for a real-time surgical simulation system. This proposed organ model allows us to perform surgical maneuvers such as pressing, pinching, various incisions, resection and to show the deformation of the inner structures such as blood vessels on our system. At the same time, we have been developing a VR cockpit suited for virtual surgery and tele-surgery. Using our cockpit, our system allows us to provide the users with an environment closely resembling the open surgery situation.

Real-time volumetric deformation for surgical simulation using force feedback device

We have aimed to develop a virtual surgery system that realizes the performance of surgical maneuvers on elastic organs and to construct an elastic organ model known as sphere-filled model. In this paper we describe a new method of deforming volumetric data in real time by using sphere-filled model. As well we modified this model to take the interference between soft tissue and rigid tissue to consideration. Furthermore basic surgical maneuvers (pushing, pinching and incision) and connection with force feedback device are realized on this model similarly to our surface model.

Development of a new three-dimensional endoscopic ultrasound system through endoscope shape monitoring

We have developed a new three-dimensional (3D) endoscopic ultrasound system (EUS) with convex scanning echoendoscope to diagnose and navigate for endoscopic puncture using the 3D image. To detect the position of the probe and to monitor the shape of the scope inside the body, we use a fiber optic tracking system which is shaped like a ribbon (Shapetape, Measurand Inc.). The fiber optic tracking system could measure bend and twist at each position of the ribbon. The position of the tip of the echoendoscope is allotted to a 2D image, and the system can reconstruct and visualize a 3D image in real-time. We have reported results of our experimental studies and animal studies.

Development of a data fusion system using color information for real-time intraoperative liver surface measurement

The goal of our study is to develop a data fusion system, which enables surgeons to easily visualize the inner structures of elastic organs during open surgery. We chose the liver as the focus of this study due to its easily deformable nature and complex vascular structures. To do so, we propose using preoperative data and supplementary intraoperative data. We captured a sequence of liver surface data for the intraoperative data by using trinocular stereo and we applied them to the preoperative 3D model's surface. Then, we modified the model to fit the intraoperative liver condition and portrayed the model's inner structures. With this method, we could establish this system.

Laparoscopic wedge resection of gastric submucosal tumors

BACKGROUND/AIMS

The purpose of this study was to evaluate the clinical utility of laparoscopic surgery for gastric submucosal tumor.

METHODS

The records of 11 patients who underwent laparoscopic wedge resection (LR group) for gastric submucosal tumors were reviewed and compared with those of 8 patients who underwent open surgery (OS group).

RESULTS

Mean operation time was 145 +/- 43 min in the LR group and 127 +/- 33 min in the OS group (p = 0.301). Mean blood loss was 97 +/- 107 and 107 +/- 47 g, respectively (p = 0.387). Patients in the LR group began walking 1.4 +/- 0.7 days after surgery, which was significantly earlier than those in the OS group (2.7 +/- 1.3 days, p = 0.021). The first flatus (1.5 +/- 0.5 vs. 3.1 +/- 0.6 days, respectively, p = 0.0004) and resumption of oral food intake (3.0 +/- 1.7 vs. 4.3 +/- 0.9 days, respectively, p = 0.020) were also earlier in the LR group. White blood cell count on the first postoperative day was lower (7,000 +/- 2,100 vs. 11,900 +/- 3,580/mm(3), respectively, p = 0.004) in the LR group than in the OS group, and the duration of fever (>38.0 degrees C; 0.1 +/- 0.3 vs. 0.9 +/- 0.8 days, respectively, p = 0.014) and the period of postoperative hospitalization (13.2 +/- 3.7 vs. 20.8 +/- 6.1 days, respectively, p = 0.014) were significantly shorter in the LR group than in the OS group. No complications occurred in either group.

CONCLUSION

Laparoscopic surgery was superior to open surgery in terms of postoperative recovery time with comparable operation time and blood loss. Laparoscopic wedge resection is a promising surgical alternative for the treatment of gastric submucosal tumors.

A large quantity of CD3-/CD19-/CD16- lymphocytes in malignant pleural effusion from a patient with recurrent cholangio cell carcinoma

Tumor infiltrating lymphocytes (TILs) are candidates for adoptive cellular immunotherapy. Here we report on a patient whose TILs presented unusual lymphocyte antigens. Pleural effusions were collected from a 47-year-old man with recurrent cholangio cell carcinoma and malignant effusion. Effusion-associated lymphocytes (EALs) were separated by Ficoll-Hypaque gradient, and the EAL phenotype was determined by flow cytometry. The percentage of positive cells was determined for each lymphocyte-related differentiation antigen. The percentages of CD3+, CD19+, and CD16+ lymphocyte subpopulations among EALs were 20%, 7%, and 3%, respectively. Nearly 70% of EALs were CD3-/CD19-/CD56-/CD16- cells. The phenotypes of peripheral blood lymphocytes (PBLs) collected simultaneously from the patient's peripheral blood were CD3+ (52%), CD19+ (20%), and CD16+ (20%). When EALs were cultured in medium without pleural effusion, T cell-related antigens, but not B cell- or natural killer (NK) cell-related antigens, were newly expressed on EALs, and this expression reached a plateau after 48 h in culture. The proportions of CD3+, CD19+, and CD16+ cells were 69%, 7%, and 3%, respectively. However, when EALs were cultured in medium with pleural effusion, increased expression of T cell-related antigens was not observed; the proportions of CD3+, CD19+, and CD16+ cells were 16%, 6%, and 1%, respectively. Neither total cell numbers nor cellular viability of EALs changed significantly after in-vitro culture, suggesting that significant proliferation or death of EALs did not occur during the culture period. Co-culture of the patient's PBLs with autologous pleural effusion for 96 h did not alter the expression of lymphocyte-related antigens on the PBLs. These results indicate that expression of T cell-related antigens, but not B cell- or NK cell-related antigens, on EALs was blocked temporarily by the malignant pleural effusion. This is the first report concerning the existence of a large quantity of unclassified lymphocytes in which the T cell-related antigens were reversibly masked in the malignant pleural effusion.

Candidate host marker for peritoneal dissemination

BACKGROUND

Mesothelial cell injury is common in peritoneal dissemination (PD) of cancer cells. The plasminogen activator system, including urokinase-type plasminogen activator (uPA) and type-1 plasminogen activator inhibitor (PAI-1), plays an important role in repair of the peritoneum damaged by several types of peritonitis. We investigated and compared the expression of uPA and PAI-1 in the peritoneum of cancer patients with and without PD.

MATERIALS AND METHODS

Cancer cell-positive peritoneum and cancer cell-negative peritoneum specimens were obtained from 11 patients with PD, while peritoneum specimens were also obtained from 24 patients without PD. The presence or absence of cancer cells in the peritoneal tissues was confirmed by both hematoxylin-eosin staining and reverse transcriptase-polymerase chain reaction (RT-PCR) detection of carcinoembryonic antigen (CEA) mRNA. uPA and PAI-1 mRNA expression in these peritoneal tissues was determined by RT-PCR and the proteins were localized immunohistochemically. The results were compared statistically.

RESULTS

uPA mRNA was expressed in the cancer cell-positive peritoneum from 9 of the 11 (81.8%) patients with PD; PAI-1 mRNA was expressed in the peritoneal tissue from 10 of (91.9%) these patients. Either uPA or PAI-1 mRNA was expressed in the cancer cell-negative peritoneum from 8 (72.7%) of the 11 patients with PD, whereas uPA mRNA was expressed in none of the peritoneal tissues from the 24 patients without PD and PAI-1 mRNA was expressed in specimens from 4 (16.7%) of these patients. Immunohistochemical analysis revealed uPA and/or PAI-1 in the mesothelial cells and submesothelial fibroblasts in cancer cell-negative peritoneum from the patients with PD but not in peritoneum from the patients without PD.

CONCLUSION

uPA transcription in the peritoneum may be a host marker indicating the existence of PD.

Impedance computed tomography using an adaptive smoothing coefficient algorithm

In impedance computed tomography, a fixed coefficient regularization algorithm has been frequently used to improve the ill-conditioning problem of the Newton-Raphson algorithm. However, a lot of experimental data and a long period of computation time are needed to determine a good smoothing coefficient because a good smoothing coefficient has to be manually chosen from a number of coefficients and is a constant for each iteration calculation. Thus, sometimes the fixed coefficient regularization algorithm distorts the information or fails to obtain any effect. In this paper, a new adaptive smoothing coefficient algorithm is proposed. This algorithm automatically calculates the smoothing coefficient from the eigenvalue of the ill-conditioned matrix. Therefore, the effective images can be obtained within a short computation time. Also the smoothing coefficient is automatically adjusted by the information related to the real resistivity distribution and the data collection method. In our impedance system, we have reconstructed the resistivity distributions of two phantoms using this algorithm. As a result, this algorithm only needs one-fifth the computation time compared to the fixed coefficient regularization algorithm. When compared to the fixed coefficient regularization algorithm, it shows that the image is obtained more rapidly and applicable in real-time monitoring of the blood vessel.

ECG data reduction method for medical telemetry systems

In current medical practice, all transmitters used for monitoring an ECG send data continuously. If transmission could be limited to only the ECG data that requires the attention of a technician, the likelihood of interference and power consumption would be reduced considerably. In this paper, we propose a new ECG telemetry system. The transmitter has a simple ECG analyzer and it only transmits data when abnormal waveforms are detected. As part of this system, we propose a simple algorithm to detect an abnormal ECG. The algorithm is composed of a baseline drift canceller (utilizing a moving average calculation), a waveform detector (using a modified second order derivative) and an ECG analyzer. In order to test the effectiveness and feasibility of the algorithm, computer simulations (with a MIT-BIH ECG database) and experiments (with microprocessor-based hardware) were performed. The results of the simulations show that the detection performance and data compression performance of the algorithm are adequate. The results of the experiment show that the algorithm even performs adequately when used with microprocessor-based hardware that is of limited size or limited power consumption.