Elevation of serum hepatocyte growth factor concentration in patients with gastric cancer is mediated by production from tumor tissue

Hepatocyte growth factor (HGF) is a stromal cell-derived cytokine that can stimulate invasion and metastasis of carcinoma cells. Recent studies have shown that the serum HGF concentration is elevated in patients with gastric cancer and may be a useful disease marker. However, the origin of the elevated serum HGF remains undetermined. We investigated the site of HGF production by analyzing the relationships between the HGF expression in tumor tissues, the serum HGF concentrations and inflammation in patients with gastric cancer. The serum and tissue HGF concentrations were measured by an enzyme-linked immunosorbent assay. The serum HGF concentration was higher than the normal cut-off level (0.57 ng/ml) in 44% of the patients. Surgical removal of the tumor significantly reduced the serum HGF concentration, suggesting that the tumor tissue was responsible for the increase. Western blotting analysis showed that the HGF protein was expressed in 20 out of 22 tumor tissues. The concentration of HGF in the tumor tissue was significantly higher than that in normal gastric mucosa. Significant correlation was found between tissue HGF concentrations and serum HGF concentrations. No significant correlation was found between the serum HGF concentration and white blood cell count or C-reactive protein concentration, indicating that the increase in serum HGF is not due to inflammation related to the tumor. These results suggest that the elevated serum HGF concentration in patients with gastric cancer is mediated by production from the tumor tissue.

Lipopolysaccharide increases cyclo-oxygenase-2 expression in a colon carcinoma cell line through nuclear factor-kappa B activation

Both nonneoplastic colon epithelium and colon carcinoma cells in situ are continuously exposed to lipopolysaccharide (LPS). Few reports have addressed possible direct effects of LPS in promotion of colon carcinoma and underlying mechanisms. We found evidence that LPS directly stimulated growth of the human colon carcinoma cell line CE-1 through an increase in the production of prostaglandin E2 (PGE2) as a result of cyclo-oxygenase-2 (COX-2) expression. LPS induced significant increases in PGE2 production in CE-1 cells, which were found to express a high-affinity LPS receptor, CD14. Positive correlations were found between PGE2 production and activation of nuclear factor (NF)-kappa B as well as expression of both COX-2 mRNA and protein in LPS-stimulated CE-1 cells. When CE-1 cells were exposed to exogenous PGE2, DNA synthesis increased. These results indicate that LPS may stimulate DNA synthesis in certain colon carcinoma cells as a result of PGE2 production involving increased COX-2 expression that might result in turn from activation of NF-kappa B by LPS. Further investigation of the pathways mediating LPS-induced stimulation of colon carcinoma cells may provide insights into LPS effects in in vivo tumor biology.

Laparoscopically assisted distal gastrectomy for early gastric cancer: is it superior to open surgery?

BACKGROUND

The purpose of this study was to compare clinical outcomes between laparoscopically assisted and open distal gastrectomy for early gastric cancer.

METHODS

The records of 21 patients who underwent laparoscopically assisted distal gastrectomy (LG) for preoperative diagnosis of intramucosal gastric carcinoma between January 1996 and August 1998 were reviewed and compared with those of 31 open distal gastrectomy patients during the same period.

RESULTS

Age, gender, and size and histologic differentiation of the lesions were matched. Those located at the body of the stomach (p = 0.011) and those macroscopically depressed (p = 0.049) were subjected more frequently to open surgery. Laparoscopically assisted gastrectomy required significantly longer operative time (p < 0.001) with less extensive lymph node dissection (p < 0.001). However, time to start of walking (p = 0.032), time to flatus (p = 0.002), duration of postoperative fever (p = 0.027), and postoperative hospital stay (p = 0.001) were significantly shorter in the LG group, and this group had a lower white blood cell count on the first postoperative day (p = 0.010). Blood loss and time to oral intake were comparable between the groups. Complications included one conversion to open surgery, one leakage, and one stenosis in the LG group, and two leakages and an atelectasis in the OG group.

CONCLUSIONS

Although LG requires longer surgical time, this retrospective study suggests that it is superior to open surgery in terms of faster postoperative recoveries, shorter hospital stays, and cosmetic outcomes.

Optimal level of pressure support ventilation for recovery from diaphragmatic fatigue in rabbits

OBJECTIVE

To determine whether there is an optimal level of pressure support ventilation (PSV) for recovery from acute diaphragmatic fatigue.

DESIGN

Prospective laboratory trial.

SETTING

Experimental laboratory.

SUBJECTS

Twenty healthy adult New Zealand White rabbits.

INTERVENTIONS

Diaphragmatic fatigue was induced with 50 Hz of phrenic nerve stimulation for 30 mins. Recovery was compared between inspiratory load + PSV of 0 cm H2O (L0), inspiratory load + PSV of 60 cm H2O (L60), inspiratory load + PSV of 80 cm H2O (L80), and PSV of 0 cm H2O without inspiratory load (SB) for 90 mins immediately after the end of the fatigue-inducing procedure. To add inspiratory load during the recovery phase, three pressure threshold valves, each having an opening pressure of -20 cm H2O, were used.

MEASUREMENTS AND MAIN RESULTS

After the fatigue-inducing procedure, diaphragmatic electromyogram and transdiaphragmatic pressure remained at baseline in both SB and L60, decreased in L80, and increased in L0. Recovery was assessed by abdominal cavity pressure (Pabd) generated by high-frequency (100 Hz) and low-frequency (20 Hz) stimulation. Pabd at 100 Hz recovered to baseline in L60 and SB but not in L0 and L80 (69.1%, 81.3%, 100.3%, and 100.7% of the baseline at 90 mins for L0, L80, L60, and SB, respectively). Pabd at 20 Hz did not differ among ventilatory settings.

CONCLUSION

There is an optimal range of PSV assist level to improve recovery from diaphragmatic fatigue. Recovery was hampered not only by inadequate PSV but also by excessive PSV.

Laparoscopically assisted distal gastrectomy for early gastric cancer: is it superior to open surgery?

BACKGROUND

The purpose of this study was to compare clinical outcomes between laparoscopically assisted and open distal gastrectomy for early gastric cancer.

METHODS

The records of 21 patients who underwent laparoscopically assisted distal gastrectomy (LG) for preoperative diagnosis of intramucosal gastric carcinoma between January 1996 and August 1998 were reviewed and compared with those of 31 open distal gastrectomy patients during the same period.

RESULTS

Age, gender, and size and histologic differentiation of the lesions were matched. Those located at the body of the stomach (p = 0.011) and those macroscopically depressed (p = 0.049) were subjected more frequently to open surgery. Laparoscopically assisted gastrectomy required significantly longer operative time (p < 0.001) with less extensive lymph node dissection (p < 0.001). However, time to start of walking (p = 0.032), time to flatus (p = 0.002), duration of postoperative fever (p = 0.027), and postoperative hospital stay (p = 0.001) were significantly shorter in the LG group, and this group had a lower white blood cell count on the first postoperative day (p = 0.010). Blood loss and time to oral intake were comparable between the groups. Complications included one conversion to open surgery, one leakage, and one stenosis in the LG group, and two leakages and an atelectasis in the OG group.

CONCLUSIONS

Although LG requires longer surgical time, this retrospective study suggests that it is superior to open surgery in terms of faster postoperative recoveries, shorter hospital stays, and cosmetic outcomes.

Benign mediastinal teratoma complicated by cardiac tamponade: report of a case

We present herein the case of a 48-year-old woman with a benign mediastinal teratoma that had been followed up for 3 years, who developed acute cardiac tamponade. The patient had initially undergone an exploratory sternotomy, at which time the tumor was histologically diagnosed as a benign mature teratoma that could not be resected due to its severe, wide adhesion to the surrounding organs. However, following the development of cardiac tamponade, both sternotomy and right intercostal thoracotomy were employed, and the tumor could be excised with cardiopulmonary bypass standby. High levels of amylase and carbohydrate antigen 19-9 were revealed in the pericardiac effusion fluid. The mRNA expression of inflammatory cytokines including interleukin-1 (IL-1), IL-6, and IL-8 in the tumor tissue was also demonstrated by a reverse transcriptase-polymerase chain reaction analysis. This case illustrates the ultimate natural course of benign mediastinal teratoma and emphasizes the importance of early surgical excision, even when this tumor is asymptomatic.

Estimation of nerve conduction velocity using surface multielectrode

The nerve conduction velocity (NCV) was measured by using the multichannel surface EMG technique. The subjects were 7 healthy volunteers (20-49 years). The evoked responses were recorded from the tibialis anterior muscle when electrically stimulating the common peroneal nerve. The distribution and propagation pattern of the nerve action potentials (NAPs) preceding M-waves could be obtained by the multichannel surface EMG. The NCV of the fastest nerve fibers could be estimated from the time delays of the latencies of the NAPs. The average NCV (ANCV) of active nerve fibers could be also estimated from the time delays of the peak latencies of the NAPs. In 4 of 7 normal subjects, the shortest latencies and the fastest NCVs were obtained with threshold stimulation. The mean values of the NCV and the ANCV with supramaximal stimulation in 7 normal deep peroneal nerves calculated by this method were 55.9 +/- 6.5 m/s and 43.3 +/- 3.2 m/s respectively.

Hepatocyte growth factor and invasion-stimulatory activity are induced in pleural fluid by surgery in lung cancer patients

Hepatocyte growth factor (HGF) is a stromal cell-derived cytokine that can stimulate matrix invasion by carcinoma cells. We analysed the concentrations of HGF and invasion-stimulatory activity in pleural fluid after lung surgery. The concentration of HGF in pleural fluids was measured by enzyme-linked immunosorbent assay in seven patients who underwent pulmonary resection for primary or metastatic lung cancer. The effect of the pleural fluid on cancer cell invasion across reconstituted basement membrane (Matrigel) was assessed with a Boyden chamber assay using a lung adenocarcinoma cell line, A549. HGF levels in the pleural fluid after lung surgery ranged from 6.0 to 23.0 ng ml(-1) (average: 10.2 +/- 4.3 ng ml(-1)). The matrix invasion of lung carcinoma cells in the presence of the pleural fluid was significantly higher than that in the presence of culture medium alone or sera from normal subjects (P < 0.01). The invasion-stimulatory activity of the pleural fluid was strongly inhibited by HGF-neutralizing antibody. Positive correlation was found between the HGF level and invasion-stimulatory activity in the pleural fluids and normal sera (P = 0.0073). This is the first report demonstrating that the lung surgery induces a considerable amount of HGF, which is closely correlated with the invasion-stimulatory activity of the pleural fluid.

Nitric oxide synthase expression and nitric oxide production in human colon carcinoma tissue

BACKGROUND AND OBJECTIVES

Nitric oxide (NO), the production of which is dependent on NO synthase (NOS), has been shown to contribute to various pathogeneses in cancer. The aim of this study was to determine whether inducible NO synthase (iNOS) is overexpressed in human colon carcinoma tissue, and whether NO is produced in tumor tissue.

METHODS

We investigated iNOS mRNA expression in 24 human colon carcinoma tissue specimens by reverse transcription-polymerase chain reaction (RT-PCR). We then examined the expression of iNOS protein and nitrotyrosine, which indicates NO production in tissue, by immunohistochemistry. The possible immunosuppressive role of NO produced by colon carcinoma cells was analyzed in vitro.

RESULTS

Semiquantitative RT-PCR analysis showed that iNOS mRNA expression in carcinoma tissues is elevated significantly compared to that in noncarcinoma tissue. Immunohistochemistry revealed that iNOS and nitrotyrosine are expressed strongly in carcinoma tissues. In vitro experiments showed that the supernatant from a culture of cytokine-treated colon carcinoma cells, which contained high levels of NO, significantly reduced the phytohemagglutinin (PHA)-stimulated, human lymphocyte proliferative response (60% of the control value).

CONCLUSIONS

In human colon carcinoma tissue, iNOS mRNA, protein, and NO products are overexpressed and may contribute to tumor-related immunosuppression.

Nitric oxide synthase expression and nitric oxide production in human colon carcinoma tissue

BACKGROUND AND OBJECTIVES

Nitric oxide (NO), the production of which is dependent on NO synthase (NOS), has been shown to contribute to various pathogeneses in cancer. The aim of this study was to determine whether inducible NO synthase (iNOS) is overexpressed in human colon carcinoma tissue, and whether NO is produced in tumor tissue.

METHODS

We investigated iNOS mRNA expression in 24 human colon carcinoma tissue specimens by reverse transcription-polymerase chain reaction (RT-PCR). We then examined the expression of iNOS protein and nitrotyrosine, which indicates NO production in tissue, by immunohistochemistry. The possible immunosuppressive role of NO produced by colon carcinoma cells was analyzed in vitro.

RESULTS

Semiquantitative RT-PCR analysis showed that iNOS mRNA expression in carcinoma tissues is elevated significantly compared to that in noncarcinoma tissue. Immunohistochemistry revealed that iNOS and nitrotyrosine are expressed strongly in carcinoma tissues. In vitro experiments showed that the supernatant from a culture of cytokine-treated colon carcinoma cells, which contained high levels of NO, significantly reduced the phytohemagglutinin (PHA)-stimulated, human lymphocyte proliferative response (60% of the control value).

CONCLUSIONS

In human colon carcinoma tissue, iNOS mRNA, protein, and NO products are overexpressed and may contribute to tumor-related immunosuppression.

An early gastric carcinoma treatment strategy based on analysis of lymph node metastasis

BACKGROUND

Newly developed therapies for early gastric carcinoma attempt to consider patients' quality of life, but the applicability and effectiveness of these treatments remain undetermined.

METHODS

Clinicopathologic data of 612 consecutive patients with early gastric carcinoma, all of whom were treated by D1 and D2 gastrectomy, were analyzed. Patients with and without lymph node metastases were compared in relation to age and gender distributions, surgical procedures, histopathology of the tumors, 5-year prognosis, and in reference to the preoperative and intraoperative assessments.

RESULTS

The overall incidence of lymph node metastases was 5.7%. Tumor depth and size were related to lymph node metastases judged by univariate and multivariate analyses. Patients with mucosal tumors showed no relation between metastatic rate and tumor size, whereas those with submucosal tumors showed an increasing metastatic rate with tumor size. In all cases but one, lymph node metastases were confined to lymph node stations defined as Group 1 locations. Preoperative endoscopic ultrasonography showed a 55% diagnostic accuracy in determining tumor depth and a 15% sensitivity in diagnosing lymph node metastases.

CONCLUSIONS

Patients with early gastric carcinoma may be candidates for endoscopic mucosal resection if their tumor is confined to the mucosa and measures < 1 cm in greatest dimension. Other limited resections including D1 gastrectomy or standard D2 gastrectomy based on tumor depth and size are appropriate. Based on the current study findings, the authors propose a useful algorithm for managing such patients.

An early gastric carcinoma treatment strategy based on analysis of lymph node metastasis

BACKGROUND

Newly developed therapies for early gastric carcinoma attempt to consider patients' quality of life, but the applicability and effectiveness of these treatments remain undetermined.

METHODS

Clinicopathologic data of 612 consecutive patients with early gastric carcinoma, all of whom were treated by D1 and D2 gastrectomy, were analyzed. Patients with and without lymph node metastases were compared in relation to age and gender distributions, surgical procedures, histopathology of the tumors, 5-year prognosis, and in reference to the preoperative and intraoperative assessments.

RESULTS

The overall incidence of lymph node metastases was 5.7%. Tumor depth and size were related to lymph node metastases judged by univariate and multivariate analyses. Patients with mucosal tumors showed no relation between metastatic rate and tumor size, whereas those with submucosal tumors showed an increasing metastatic rate with tumor size. In all cases but one, lymph node metastases were confined to lymph node stations defined as Group 1 locations. Preoperative endoscopic ultrasonography showed a 55% diagnostic accuracy in determining tumor depth and a 15% sensitivity in diagnosing lymph node metastases.

CONCLUSIONS

Patients with early gastric carcinoma may be candidates for endoscopic mucosal resection if their tumor is confined to the mucosa and measures < 1 cm in greatest dimension. Other limited resections including D1 gastrectomy or standard D2 gastrectomy based on tumor depth and size are appropriate. Based on the current study findings, the authors propose a useful algorithm for managing such patients.

Mediastinal lymph node metastasis of colon cancer: report of a case

We herein describe a patient with mediastinal lymph node metastases which occurred after both a primary sigmoid colon cancer and metachronous ovarian metastasis had been resected. The most likely route of metastases to the mediastinum in this case is the paravertebral venous plexus probably connected to the ovarian metastasis, or so-called remetastasis. This case illustrates that the mediastinum is thus a possible metastatic site in patients with colon cancer. Surgeons should therefore pay attention to the mediastinum as well as the lung fields when checking chest X-ray films during a follow-up of patients after a resection of colon cancer.

Nitric oxide synthase expression and nitric oxide production in human colon carcinoma tissue

BACKGROUND AND OBJECTIVES

Nitric oxide (NO), the production of which is dependent on NO synthase (NOS), has been shown to contribute to various pathogeneses in cancer. The aim of this study was to determine whether inducible NO synthase (iNOS) is overexpressed in human colon carcinoma tissue, and whether NO is produced in tumor tissue.

METHODS

We investigated iNOS mRNA expression in 24 human colon carcinoma tissue specimens by reverse transcription-polymerase chain reaction (RT-PCR). We then examined the expression of iNOS protein and nitrotyrosine, which indicates NO production in tissue, by immunohistochemistry. The possible immunosuppressive role of NO produced by colon carcinoma cells was analyzed in vitro.

RESULTS

Semiquantitative RT-PCR analysis showed that iNOS mRNA expression in carcinoma tissues is elevated significantly compared to that in noncarcinoma tissue. Immunohistochemistry revealed that iNOS and nitrotyrosine are expressed strongly in carcinoma tissues. In vitro experiments showed that the supernatant from a culture of cytokine-treated colon carcinoma cells, which contained high levels of NO, significantly reduced the phytohemagglutinin (PHA)-stimulated, human lymphocyte proliferative response (60% of the control value).

CONCLUSIONS

In human colon carcinoma tissue, iNOS mRNA, protein, and NO products are overexpressed and may contribute to tumor-related immunosuppression.

[Postoperative respiratory management in patients undergoing radical surgery with three fields lymph node dissection for thoracic esophageal cancer: clinical benefits of assisted ventilation with mini-tracheostomy]

The benefits of early extubation and assisted ventilation with mini-tracheostomy and preventive positive pressure ventilation in the early stage after thoracic esophageal cancer operation are examined and compared. Subjects were 23 patients who underwent radical operation for thoracic esophageal cancer in our hospital over a 5 year period. Ten patients (A group) underwent positive pressure ventilation with postoperative intubation for a certain period. Thirteen patients (B group) were extubated the day after operation, then immediately mini-tracheostomized, and then intermittent high-frequency jet ventilation during the daytime and pressure controlled ventilation during the nighttime were conducted. There were no differences in background factors between the two groups. The mean period of tracheal intubation was 8.8 days in the A group and 1.6 days in the B group. The mean period of stay in ICU was 13 days in the A group and 7 days in the B group. Both such periods were significantly shorter in the B group than in the A group. Respiratory control by early extubation and mini-tracheostomy after thoracic esophageal cancer operation is considered to have the following two benefits; 1. The method is performed safely, and makes sputum suction easier and assisted respiration conductible. 2. The method reduces the incidence of pulmonary complications and shortens the period of stay in ICU.

Dynamic measurement of intrinsic PEEP does not represent the lowest intrinsic PEEP

OBJECTIVE

Dynamic intrinsic PEEP (PEEPi-dyn) is the airway pressure required to overcome expiratory flow and is considered to represent the lowest regional PEEPi. However, there are few data to validate this assumption. We investigated if PEEPi-dyn represents the lowest PEEPi.

SETTING

The animal laboratory at the Osaka University Medical School.

MEASUREMENTS AND RESULTS

We compared static PEEPi (PEEPi-stat) and PEEPi-dyn in healthy animals. Five adult white rabbits (2.77+/-0.05 kg) were anesthetized, tracheostomized, and intubated with several different sizes of endotracheal tubes (ETT) (2.0, 2.5, 3.0, 3.5, or 4.0 mm i.d.). The animals were paralyzed and ventilated (Siemens Servo 900C). Baseline ventilator settings were at a rate of 50/min, inspiratory:expiratory (I:E) ratio of 2:1 or 4:1, and minute ventilation was manipulated to create 3 or 5 cm H2O PEEPi-stat. PEEPi-stat was measured using the expiratory hold button of the ventilator. PEEPi-dyn showed large variations. In all ventilator settings, PEEPi-dyn was higher than PEEPi-stat (p<0.001). The larger the ETT, the higher the PEEPi-dyn at an I:E ratio of 2:1 (p<0.05). The higher the minute ventilation, the greater the difference between PEEPi-stat and PEEPi-dyn. The tidal volume and the difference showed a significant correlation (r2 = 0.514, p<0.001).

CONCLUSIONS

The value of PEEPi-dyn was dependent on ventilatory settings, and PEEPi-dyn does not necessarily represent the lowest regional PEEPi within the lungs.

Adrenoleukodystrophy protein enhances association of very long-chain acyl-coenzyme A synthetase with the peroxisome

OBJECTIVE

To clarify the function of adrenoleukodystrophy protein (ALDP) using our ALDP-deficient mice established by gene targeting.

BACKGROUND

X-linked adrenoleukodystrophy (ALD) is characterized biochemically by the accumulation of very long-chain fatty acids (VLCFA) in tissues and body fluids, and is caused by impairment of peroxisomal beta-oxidation. In ALD, very long-chain acyl-coenzyme A synthetase (VLACS), which is necessary for peroxisomal beta-oxidation, does not function.

METHODS

The ALDP-deficient mice and C57BL/6J mice were used. VLACS or ALDP were transiently expressed by lipofection in murine fibroblasts, and VLCFA beta-oxidation was assayed. Liver peroxisomes were purified by sequential centrifugations and a Nycodenz gradient centrifugation. The peroxisomal localization of VLACS was compared between the mutant and control mice using a Western blot analysis.

RESULTS

Impairment of VLCFA beta-oxidation in ALDP-deficient fibroblasts was not corrected by the additional expression of VLACS alone but was by the coexpression of VLACS and ALDP. Although the tissue-specific expression of VLACS was similar in ALDP-deficient and normal mice, peroxisomal VLACS was clearly lower in ALDP-deficient than in normal mice.

CONCLUSIONS

ALDP plays a role in the peroxisomal localization of VLACS, and VLACS does not function unless localized in the peroxisome.

Chitosanase activity of the enzyme previously reported as beta-1,3-1,4-glucanase from Bacillus circulans WL-12

Chitosanases 33 kDa and 40 kDa in size were detected in the culture supernatant of Bacillus circulans WL-12. One of the two chitosanases, chitosanse 40 (40-kDa chitosanase) has been shown to be identical to the enzyme which has been reported previously as a beta-1,3-1,4-glucanase by Bueno et al. The enzyme has been classified into family 8 glycosyl hydrolases together with the enzymes formally known as cellulase family D. This enzyme named chitosanase 40/beta-1,3-1,4-glucanase hydrolyzed both chitosan and beta-1,3-1,4-glucan with similar efficiency. However, the production of the enzyme was induced with chitosan but not by beta-1,3-1,4-glucan. Therefore, it seems possible that the major substrate of this enzyme is chitosan rather than beta-1,3-1,4-glucan. Analysis of degradation products generated from partially N-acetylated chitosan showed that chitosanase 40/beta-1,3-1,4-glucanse hydrolyzes GlcN-GlcN and GlcN-GlcNAc linkages but not GlcNAc-GlcNAc nor GlcNAc-GlcN. The specificity for hydrolyzing linkages of this enzyme is similar to that of the chitosanase from S. griseus HUT6037.

Effects of pressure-support ventilation on recovery from acute diaphragmatic fatigue in rabbits

OBJECTIVES

To examine the effects of pressure-support ventilation on recovery from acute diaphragmatic fatigue.

DESIGN

Prospective laboratory trial.

SETTING

Experimental laboratory.

SUBJECTS

Twenty-one healthy, adult New Zealand white rabbits.

INTERVENTIONS

Diaphragmatic fatigue was induced with 50-Hz phrenic nerve stimulation for 30 mins. Recovery was compared between pressure-support ventilation 0 cm H2O (SB), 10 cm H2O (P10), and 20 cm H2O (P20) for 90 mins immediately after the end of the fatigue inducing procedure.

MEASUREMENTS AND MAIN RESULTS

After the fatigue-inducing procedure, pressure-support ventilation reduced transdiaphragmatic pressure and integrated diaphragmatic electromyogram both at P20 and P10, but not in SB. Recovery was assessed by airway occlusion pressure (Poccl) generated by high- (100 Hz) and low- (20 Hz) frequency phrenic nerve stimulation. Poccl at 100 Hz was lower in P10 and P20 than in SB (74.6 +/- 6.2 [SEM] %, 66.9 +/- 3.3%, and 94.8 +/- 3.6% of the baseline at 90 mins for P10, P20, and SB, respectively), while those at 20 Hz showed no differences between the three groups.

CONCLUSION

Recovery from acute diaphragmatic fatigue might be disturbed with pressure-support ventilation.

[Creation of a dynamic digital phantom and its application to a kinetic analysis]

A dynamic digital brain phantom was created from the MRI to evaluate visually the relationship between the noise and the error in the parameter estimates in the PET kinetic analysis. This phantom incorporates the noise level depending on administration dose, camera efficiency and the data acquisition schedule. We simulated a serial dynamic scan with 18F-FDG or 11C-flumazenil, assuming 2-tissue 3-parameter model and 1-tissue 2-parameter model, respectively, and the sampling schedule was determined according to the clinical examination. The noise in the tissue time activity curve in FDG had a peak in the first minute and decreased thereafter, whereas the noise increased gradually in the flumazenil study after the initial peak due to radioactivity decay. We examined the relationship between the noise level and the error in the parameter estimates. Both mean absolute differences between true and estimated values and standard deviation became large, and the quality of the parametric images became poor with increasing noise level. This simulation was compared with human tissue time activity curves and parametric images, which were obtained with 100 MBq administration dose in FDG study and 430 MBq in flumazenil study. We inferred that the noise level in the human study was 10-20% in FDG, and 20-40% in flumazenil, and the error in the estimated parameter of K-complex in FDG study was about 20%, that of DV in flumazenil study was 2%.

Developmental characteristics in sustained fetal tachycardia in 30 to 41 weeks of gestation

The aim of the present study is to reveal gestational age-related changes in sustained foetal tachycardia (SFT). 24 h fetal heart rate (FHR) recordings were made on 102 normal pregnant women in 30-41 weeks of gestation. SFT was defined as an increase for 20 or more beats per minute from the FHR-baseline persisting for more than 20 min. In the results, SFTs in 38-39 weeks started during night-time (1900-0700) more frequently than during day-time (0700-1900) (P < 0.01, by chi-square test). The rate and duration were 0% and 0 min in 30-31 weeks of gestation, and increased to 85% and 114 min in 40-41 weeks, respectively. Two critical points were detected by a piecewise linear regression analysis: in the rate between 34-35 weeks and 36-37 weeks, and in the duration between 38-39 to 40-41 weeks. We conclude that gestational age-related changes in SFT depend on the developmental stages.

Optimization of the Advanced Earth Observing Satellite II Global Imager channels by use of radiative transfer calculations

The channel specifications of the Global Imager onboard the Advanced Earth Observing Satellite II have been determined by extensive numerical experiments. The results show that there is an optimum feasible position for each ocean color channel. The bandwidth of the 0.763-microm channel should be less than 10 nm for good sensitivity to the cloud top height and geometric thickness of the cloud layer; a 40-nm bandwidth is suitable for the 1.38-microm channel to have the strongest contrast between cloudy and clear radiance with a sufficient radiant energy; and a 3.7-microm channel is better than a 3.95-microm channel for estimation of the sea surface temperature (SST) and determination of the cloud particle size when the bandwidth of the channel is 0.33 microm. A three-wavelength combination of 6.7, 7.3, and 7.5 microm is an optimized choice for water vapor profiling. The combination of 8.6, 10.8, and 12.0 microm is suitable for cloud microphysics and SST retrievals with the split-window technique.