An efficient method for calculating kinetic parameters in a dual-input single-compartment model

Quantitative measurement of hepatic perfusion has the potential to provide important information in the assessment and management of various liver diseases. The utility of hepatic perfusion characterization relies on the resolution of each component of its dual blood supply, i.e. the hepatic artery and portal vein. In this study, a linear equation was derived by integrating the differential equation describing the kinetic behaviour of contrast agent (CA) in a dual-input single-compartment model, from which the kinetic parameters can be easily obtained using the linear least-squares method. The usefulness of this method was investigated using computer simulations, in comparison with the non-linear least-squares (NLSQ) method. This method calculated the kinetic parameters faster than the NLSQ method by a factor of approximately 10, with almost the same accuracy as the NLSQ method. This method will be useful for analysing the kinetic behaviour of CA in the unique liver environment, especially by generating the functional images of kinetic parameters.

Promotion of medial collateral ligament healing using a high-voltage electrical field

PURPOSE

To assess the biomechanical and histological effects of a high-voltage electrical field on ligament healing.

METHODS

54 male Wistar rats were used. The medial collateral ligaments (MCLs) of 6 rats were measured for normal biomechanical failure load and stiffness. MCLs of the remaining 48 rats were transected and randomly assigned; half were subjected to a high-voltage electrical field for 8 hours a day (experimental group), and the other half were kept under normal conditions (control group). Eight rats from each group were killed 2, 4, and 6 weeks after the transection and their MCLs were tested biomechanically and histologically.

RESULTS

Failure load and stiffness of the MCLs in the experimental group were significantly higher than those in the control group 2 weeks after transection, but not thereafter. At week 2, the granulation tissue completely occupied the space between the cut ends of the MCL in the experimental group, whereas some gaps remained in the control group.

CONCLUSION

A high-voltage electrical field appear to accelerate ligament healing in the initial 2 weeks. Earlier initial healing may allow earlier start of the rehabilitation.

Relationship between variations in the circle of Willis and flow rates in internal carotid and basilar arteries determined by means of magnetic resonance imaging with semiautomated lumen segmentation: reference data from 125 healthy volunteers

BACKGROUND AND PURPOSE

Volume flow rates in the feeding arteries of the brain are measured to evaluate blood flow dynamics in vascular disease. Although these flow values are thought to be effected by anatomic variations in the circle of Willis, few reports have described the effect. This study reports on the relationship between variations in the circle of Willis and volume flow rates in the bilateral internal carotid and basilar arteries of normal volunteers.

METHODS

We prospectively examined 125 healthy volunteers by MR imaging. Variations in the circle of Willis were classified as "textbook" type, hypoplasia of the precommunicating segment of the anterior cerebral artery (A1), hypoplasia of the precommunicating segment of the posterior cerebral artery (P1), or "other." Volume flow rates were measured by 2D cine phase-contrast MR imaging. Lumen boundaries and volume flow rates were semiautomatically determined by pulsatility-based segmentation.

RESULTS

Of the 117 subjects (61 men, 56 women; mean age, 23.6 years) considered suitable for flow measurement, 105 showed textbook type, and 6 each showed A1 hypoplasia and P1 hypoplasia. Total flow rates for the 3 variations were 781 +/- 151 mL/min (mean +/- SD), 744 +/- 119, and 763 +/- 129, respectively. Relative contributions by flow rates of the internal carotid arteries and the basilar artery for the 3 variations were 39.8%:38.9%:21.3%, 31.8%:49.1%:19.0%, and 46.6%:41.6%:11.7%, respectively, showing statistically significant differences.

CONCLUSIONS

Variations in the circle of Willis correlate significantly with relative contributions by the flow rates of the bilateral internal carotid and basilar arteries.

Composite Hypo-Hyper-d-Intermetallic and Interionic Phases as Supported Interactive Electrocatalysts

Interactive, strong interbonding and highly electron conductive nonstoichiometric titanium suboxide catalytic supports, Magneli phases (Ti(n)O(2n-1), on average Ti(4)O(7)), have been used in the electrocatalysis of hydrogen (HELR) and oxygen (OELR) electrode reactions with remarkable consequences and advanced achievements. The theory of hypo-hyper-d-interelectronic bonding of transition metal ions and atoms has been employed for selective ordered grafting and shown to stay in the core of the strong metal-support interaction (SMSI) in heterogeneous catalysis and electrocatalysis, and thereby the substantial cause for the improved synergistic activity of composite (electro)catalysts. The same fundament has been the thermodynamic basis for the thermal production of symmetric intermetallic Laves type phases of nanostructured electrocatalysts, in particular the ones with higher oxophilic properties of hypo-d-elements. Remarkably advanced in electrocatalytic activity, highly monatomically dispersed deposits of Pt upon Magneli phases are shown to be unique and highly promising electrocatalysts for the cathodic oxygen reduction (ORR). Nanostructured Au upon a thin nanocrystalline film of anatase titania has been confirmed by X-ray photoelectron spectroscopy (XPS) as a typical classical paradigm of the SMSI, and at the same time affording the basis for gold with strained d-orbitals, as the reversible hydrogen electrode. Magneli phases have been shown to be the best electrocatalytic supports with unique properties both for low temperature PEM fuel cells (LT PEM FCs) with pronounced CO tolerance and water electrolysis in membrane type hydrogen generators.

Comparison of patient doses in 256-slice CT and 16-slice CT scanners

The 256-slice CT-scanner has been developed at the National Institute of Radiological Sciences. Nominal beam width was 128 mm in the longitudinal direction. When scanning continuously at the same position to obtain four-dimensional (4D) images, the effective dose is increased in proportion to the scan time. Our purpose in this work was to measure the dose for the 256-slice CT, to compare it with that of the 16-slice CT-scanner, and to make a preliminary assessment of dose for dynamic 3D imaging (volumetric cine imaging). Our group reported previously that the phantom length and integration range for dosimetry needed to be at least 300 mm to represent more than 90% of the line integral dose with the beam width between 20 mm and 138 mm. In order to obtain good estimates of the dose, we measured the line-integral dose over a 300 mm range in PMMA (polymethylmethacrylate) phantoms of 160 mm or 320 mm diameter and 300 mm length. Doses for both CT systems were compared for a clinical protocol. The results showed that the 256-slice CT generates a smaller dose than the 16-slice CT in all examinations. For volumetric cine imaging, we found an acceptable scan time would be 6 s to 11 s, depending on examinations, if dose must be limited to the same values as routine examinations with a conventional multidetector CT. Finally, we discussed the studies necessary to make full use of volumetric cine imaging.

Cloning and sequencing of a chitinase gene from Vibrio alginolyticus H-8

A gene from Vibrio alginolyticus H-8, encoding chitinase, designated as chitinase B, was cloned by the shot-gun method using pUC118 and sequenced. The open reading frame consisted of 846 amino acids including a signal peptide. The molecular mass of the enzyme estimated based on the amino acid sequence data was 90 kDa. The N-terminal amino acid sequence of the enzyme was different from that of chitinase C1 which we had previously reported. This cloned chitinase B was considered one out of four chitinases (A, B, D, and E) which had been newly isolated from the culture broth and cell extract of V. alginolyticus H-8. The gene contained a chitin-binding domain and typical conserved regions of chitinases reported previously. The deduced amino acid sequence of the cloned chitinase B showed high sequence homology with the chitinase from V. parahaemolyticus (84% identity) and the chitinase from V. anguillarum (76.6%), but low sequence homology with the chitinase from V. harveyi (24.4%), and the chitodextrinase from V. furnissii (23.9%). Chitinase E found in cell extract is considered an intracellular chitinase which is different from chitodextrinases.

Cloning and sequencing of the deacetylase gene from Vibrio alginolyticus H-8

A gene encoding deacetylase DA1 that is specific for N, N'-diacetylchitobiose was cloned using the shot-gun method with pUC118 and sequenced. The open reading frame encoded a protein of 427 amino acids including the signal peptide. The molecular mass of the mature enzyme estimated from the amino acid sequence data was 44.7 kDa, which is approximately similar to that, estimated by SDS-PAGE (48.0 kDa), of the purified enzyme reported previously. The N-terminal amino acid sequence deduced from the cloned deacetylase gene showed partial sequence homology with the Nod B protein from Rhizobium sp. (37% identity) and chitin deacetylase from Mucor rouxii (28%). It contained a domain, which showed homology with a chitin-binding domain of chitinase A from Bacillus circulans (39%).

Effectiveness of flexible noise control image processing for digital portal images using computed radiography

The purpose of this study was to evaluate the clinical efficacy of flexible noise control (FNC) image processing in off-line computed radiography (CR) portal images. An observer study was designed to compare FNC with multiobjective frequency processing (MFP) in images acquired using a CR portal imaging device (CRPID). The image processing of MFP and FNC used the same data and required no additional irradiation of patients, and all images were printed on 10-bit grey-level dry laser film. Four radiation technologists and one oncologist served as observers and evaluated 40 sets of images for three different treatment sites: brain, lung and pelvis. Six to 10 anatomical landmarks were selected from each treatment site. Each observer was asked to rate each landmark in terms of its clinical visibility and rate the ease of making the pertinent verification in the MFP- and FNC-processed images. In the ratings of the visibility of landmarks and for the verification of treatment ports, FNC-processed images were more visible than MFP-processed images except for several landmarks in the anteroposterior (AP) pelvis such as the pubic symphysis. The visibility of landmarks in FNC-processed images was comparable with that in MFP-processed images. The verification of treatment ports using the CRPID with FNC was generally achievable. In conclusion, this study suggests that FNC is effective for image processing of CR portal images.

Chaotic dynamics of a behavior-based miniature mobile robot: effects of environment and control structure

To study the regularity and complexity of autonomous behavior, the flow of sensory information obtained in autonomous mobile robots under various conditions was analyzed as a complex system. Sensory information time series Xn was collected from a miniature mobile robot during free navigation, and plotted on the return map, the graph of X(n+tau) vs. Xn. The plot exhibited a characteristic trajectory, representing the regularity of the time series. Correlation integral and Lyapunov exponent analysis also showed properties of deterministic chaos; the presence of fractal dimension and positive Lyapunov exponent. Analysis of sensory information obtained in the robot with three different neural controllers revealed that the autonomous robot behaves in such a way that the flow of sensory information is governed by a deterministic rule, and this pattern is unique to each controller. Furthermore, the analysis in various environments exhibited that transitions from one trajectory to another on the return map occur during the course of autonomous behavior. The fractal and Lyapunov dimensions calculated in various conditions indicate that these dimension could be utilized to quantify the complexity of autonomous behavior and the relative difficulty of tasks. Analyses at different evolutionary stage revealed that behavioral performance correlates with fractal dimension. These studies using a miniature mobile robot that allowed to idealize the experimental conditions demonstrated firmly that the complex analysis could be utilized in evaluation and optimization of autonomous systems and the behavior.

Autoimmunity to Heat Shock Protein 40 in Ulcerative Colitis

Autoantibodies against heat shock protein 40 (HSP40) and their clinical significance in ulcerative colitis (UC) have not been evaluated before. Twenty-six tissue specimens of inflamed areas from patients with UC, 16 from patients with Crohn's disease (CD) and 16 endoscopically normal tissues were analysed for HSP40 expression. Sera from 47 patients with UC and 44 healthy volunteers were examined for the presence of autoantibodies against HSP40 by enzyme-linked immunosorbent assay test. Immunohistochemistry showed that 17 out of 26 specimens from UC patients, one specimen from a CD patient and one normal tissue specimen were positive for HSP40. Most HSP40-positive cells expressed CD68. Higher titres of anti-HSP40 autoantibodies were detected in sera from UC patients compared with healthy volunteers. In patients with inactive disease, those with proctitis or left-sided colitis had higher titres of anti-HSP40 autoantibodies than those with total colitis. Our study suggests that autoimmunity against HSP40 may have a beneficial effect in UC patients by limiting the extent of the disease.

High-dose rabeprazole-amoxicillin versus rabeprazole-amoxicillin-metronidazole as second-line treatment after failure of the Japanese standard regimen for Helicobacter pylori infection

BACKGROUND

There is currently no optimal second-line treatment after failure of Helicobacter pylori triple therapy.

AIM

To determine effective salvage therapy after failure of lansoprazole-amoxicillin-clarithromycin.

METHODS

After failure of lansoprazole-amoxicillin-clarithromycin 123 out-patients were randomized to receive either 2-week rabeprazole (20 mg b.d.) + amoxicillin (1000 mg b.d.) (RA group) or 1-week rabeprazole (10 mg b.d.) + amoxicillin (750 mg twice b.d.) + metronidazole (250 mg b.d.) (RAM group). Eradication was assessed by the 13C-urea breath test. We also evaluated cytochrome p450 (CYP) 2C19 genotype status, determined by polymerase chain reaction - restriction fragment length polymorphism, and susceptibility to clarithromycin and metronidazole.

RESULTS

On an intention-to-treat basis, H. pylori infection cure was achieved in 37 of 63 (59%) patients in the RA group and in 49 of 60 (82%) patients in the RAM group. Per protocol-based eradication rates in the RA and RAM groups were 66% (37/56) and 88% (49/56), respectively. In both analytic sets there were significant differences between the treatment groups (P < 0.01 in each). Mild adverse events were observed in eight and five patients from the RA and RAM groups, respectively. Genetic predisposition of CYP2C19 and antibiotic resistance did not influence the treatment outcome either regimen.

CONCLUSIONS

The rabeprazole + amoxicillin + metronidazole therapy yielded satisfactory results. In contrast, the cure rate in high-dose rabeprazole + amoxicillin was below an acceptable level.

High-dose rabeprazole-amoxicillin versus rabeprazole-amoxicillin-metronidazole as second-line treatment after failure of the Japanese standard regimen for Helicobacter pylori infection

BACKGROUND

There is currently no optimal second-line treatment after failure of Helicobacter pylori triple therapy.

AIM

To determine effective salvage therapy after failure of lansoprazole-amoxicillin-clarithromycin.

METHODS

After failure of lansoprazole-amoxicillin-clarithromycin 123 out-patients were randomized to receive either 2-week rabeprazole (20 mg b.d.) + amoxicillin (1000 mg b.d.) (RA group) or 1-week rabeprazole (10 mg b.d.) + amoxicillin (750 mg twice b.d.) + metronidazole (250 mg b.d.) (RAM group). Eradication was assessed by the 13C-urea breath test. We also evaluated cytochrome p450 (CYP) 2C19 genotype status, determined by polymerase chain reaction - restriction fragment length polymorphism, and susceptibility to clarithromycin and metronidazole.

RESULTS

On an intention-to-treat basis, H. pylori infection cure was achieved in 37 of 63 (59%) patients in the RA group and in 49 of 60 (82%) patients in the RAM group. Per protocol-based eradication rates in the RA and RAM groups were 66% (37/56) and 88% (49/56), respectively. In both analytic sets there were significant differences between the treatment groups (P < 0.01 in each). Mild adverse events were observed in eight and five patients from the RA and RAM groups, respectively. Genetic predisposition of CYP2C19 and antibiotic resistance did not influence the treatment outcome either regimen.

CONCLUSIONS

The rabeprazole + amoxicillin + metronidazole therapy yielded satisfactory results. In contrast, the cure rate in high-dose rabeprazole + amoxicillin was below an acceptable level.

Comparison of the microbicidal activities of superoxidized and ozonated water in the disinfection of endoscopes

The microbicidal activities of superoxidized water (electrolysed strong acid water [ESAW] or electrolysed weak acid water [EWAW]), ozonated water, 0.05% chlorhexidine and 2% glutaraldehyde were tested against seven strains of clinical micro-organism isolates. Following incubation of bacterial suspensions in ESAW and EWAW for 10 s, the number of micro-organisms was reduced below the detection limit. The microbicidal activities of ESAW and EWAW were similar to that of glutaraldehyde, and superior to ozonated water and 0.05% chlorhexidine. The microbicidal activities of ESAW, EWAW and ozonated water were markedly diminished in the presence of albumin. Microbial contamination of upper gastrointestinal endoscopes was detected after 90 endoscopic procedures, but treatment of the endoscope with ESAW, EWAW or ozonated water eradicated the microbes. These results indicate that ESAW and EWAW are effective disinfectants after mechanical cleaning of upper gastrointestinal endoscopes, and can, therefore, be used in the endoscopy unit.

Impact of CagA status on serum gastrin and pepsinogen I and II concentrations in Japanese children with Helicobacter pylori infection

The study aimed to determine the association between cytotoxin-associated gene product (CagA), serum gastrin and pepsinogen levels in Japanese children infected with Helicobacter pylori. Three hundred children were enrolled in the study. H. pylori infection was assessed using an enzyme-linked immunosorbent assay, and CagA status was assessed using immunoblotting. Serum gastrin and pepsinogen concentrations were measured by radioimmunoassay. H. pylori seroprevalence was 12.3% (37/300) and CagA status was identified in 28/37 H. pylori-seropositive children (75.7%). Serum pepsinogen I and II levels were significantly higher in CagA-seropositive than CagA-seronegative children with H. pylori infection. There was no significant relationship between CagA seropositivity and serum gastrin levels. In conclusion, CagA status has a significant impact on serum pepsinogen levels, possibly through enhanced gastric mucosal inflammation.

Expression of interleukin 6 and its receptor in human gastric and colorectal cancers

Interleukin 6 (IL-6) is a pleiotropic cytokine with many physiological functions. The present study was designed to determine the expression of IL-6 and its receptor (IL-6R) in human gastric and colorectal cancers. Nine gastric- and nine colorectal cancer cell lines were analysed. The IL-6 gene was expressed in two gastric cancer cell lines and one colorectal cancer cell line; however, most of the cancer cell lines studied expressed the IL-6R gene. The level of IL-6 secretion in the gastric cancer cell lines correlated with the level of soluble IL-6R secretion, and was significantly higher (< approximately 100 pg/ml) than the level of IL-6 secretion in the colorectal cancer cell lines (< approximately 50 pg/ml). These results suggest that IL-6 may act in a paracrine fashion rather than an autocrine fashion in these cell lines.

Polymorphism of CYP2C19 and gastric emptying in patients with proton pump inhibitor-resistant gastric ulcers

The aim of the present study was to investigate whether CYP2C19 polymorphism status and gastric emptying are related to healing in patients with gastric ulcers. We studied the CYP2C19 status in seven patients with proton pump inhibitor (PPI)-resistant ulcers, 21 with PPI-sensitive ulcers and 46 healthy volunteers using polymerase chain reaction restriction fragment length polymorphism to detect CYP2C19m1 mutation in exon 5 and CYP2C19m2 mutation in exon 4. Gastric emptying was evaluated using the 13C-acetate breath test. The frequency of phenotypes, indicated by genotypes, did not differ significantly between the three patient groups. The peak time of 13C excretion in patients with PPI-resistant ulcers was significantly longer than that of patients with PPI-sensitive ulcers and healthy volunteers. Our results suggest that rate of gastric emptying, but not CYP2C19 polymorphism, is likely to be an important factor in the delayed healing of patients with PPI-resistant gastric ulcer.

Accumulation of mast cells and macrophages in focal active gastritis of patients with Crohn's disease

BACKGROUND/AIMS

Recent studies have shown that focal active gastritis seems to be the typical gastric pathology in Crohn's disease. The aim of this study was to compare the incidence of focal active gastritis, Helicobacter pylori infection and distribution of gastric mast cells and macrophages in patients with Crohn's disease, ulcerative colitis and H. pylori gastritis without inflammatory bowel disease.

METHODOLOGY

Patients with histologically confirmed Crohn's disease (n = 25) or ulcerative colitis (n = 25) and control patients without inflammatory bowel disease (n = 25) were included in this study. Biopsy specimens were obtained from the antrum and corpus of each patient, and stained with hematoxylin and eosin and immunostained using antibodies to tryptase (AA1) and CD68. The number of mast cells and macrophages located in the lamina propria was determined.

RESULTS

Focal active gastritis was detected in 54% of H. pylori-negative patients with Crohn's disease, but it was not found in patients with ulcerative colitis nor in the control group. The density of mast cells and macrophages in the lamina propria of H. pylori-positive patients was significantly higher than in H. pylori-negative patients in all groups. In the Crohn's disease group, the number of mast cells (antrum; 83 +/- 11, body; 89 +/- 11/mm2) and macrophages (antrum; 94 +/- 22, body; 92 +/- 17/mm2) in the lamina propria of H. pylori-negative patients with focal active gastritis was halfway between that in H. pylori-positive and H. pylori-negative patients. In focal active gastritis, mast cells accumulated at the border of focal active gastritis, whereas macrophages accumulated in the center of such lesions.

CONCLUSIONS

Our findings indicated that the diagnosis of focal active gastritis, using immunostain for mast cells and macrophages, is the histological hallmark of gastric Crohn's disease. Macrophages might be associated with the formation of focal active gastritis in patients with Crohn's disease.

Anomalous X-Ray Scattering Studies on Glassy GexSe1−x across the Stiffness Threshold Composition x = 0.20

Anomalous x-ray scattering experiments on glassy Ge

Receiver operating characteristic (ROC) analysis of images reconstructed with iterative expectation maximization algorithms

PURPOSE

The quality of images reconstructed by means of the maximum likelihood-expectation maximization (ML-EM) and ordered subset (OS)-EM algorithms, was examined with parameters such as the number of iterations and subsets, then compared with the quality of images reconstructed by the filtered back projection method.

METHODS

Phantoms showing signals inside signals, which mimicked single-photon emission computed tomography (SPECT) images of cerebral blood flow and myocardial perfusion, and phantoms showing signals around the signals obtained by SPECT of bone and tumor were used for experiments. To determine signals for recognition, SPECT images in which the signals could be appropriately recognized with a combination of fewer iterations and subsets of different sizes and densities were evaluated by receiver operating characteristic (ROC) analysis. The results of ROC analysis were applied to myocardial phantom experiments and scintigraphy of myocardial perfusion.

RESULTS

Taking the image processing time into consideration, good SPECT images were obtained by OS-EM at iteration No. 10 and subset 5. CONCLULSION: This study will be helpful for selection of parameters such as the number of iterations and subsets when using the ML-EM or OS-EM algorithms.

Accuracy of deconvolution analysis based on singular value decomposition for quantification of cerebral blood flow using dynamic susceptibility contrast-enhanced magnetic resonance imaging

Deconvolution analysis (DA) based on singular value decomposition (SVD) has been widely accepted for quantification of cerebral blood flow (CBF) using dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI). When using this method, the elements in the diagonal matrix obtained by SVD are set to zero when they are smaller than the threshold value given beforehand. In the present study, we investigated the effect of the threshold value on the accuracy of the CBF values obtained by this method using computer simulations. We also investigated the threshold value giving the CBF closest to the assumed value (optimal threshold value) under various conditions. The CBF values obtained by this method largely depended on the threshold value. Both the mean and the standard deviation of the estimated CBF values decreased with increasing threshold value. The optimal threshold value decreased with increasing signal-to-noise ratio and CBF, and increased with increasing cerebral blood volume. Although delay and dispersion in the arterial input function also affected the relationship between the estimated CBF and threshold values, the optimal threshold value tended to be nearly constant. In conclusion, our results suggest that the threshold value should be carefully considered when quantifying CBF in terms of absolute values using DSC-MRI for DA based on SVD. We believe that this study will be helpful in selecting the threshold value in SVD.