The role of the ADC value in the characterisation of renal carcinoma by diffusion-weighted MRI

The purpose of this study is to evaluate the role of diffusion-weighted imaging (DWI) in combination with T(1) and T(2) weighted MRI for the characterisation of renal carcinoma. The institutional review board approved the study protocols and waived informed consent from all of the patients. 47 patients (32 male and 15 female; age range, 21-85 years; median age, 65 years) who had suspected renal lesions on abdominal CT underwent MRI for further evaluation and characterisation of the lesions from April 2005 to August 2007 in our university hospital. A region of interest was drawn around the tumour area on apparent diffusion coefficient (ADC) maps. Final diagnosis was confirmed by histological examination of surgical specimens from all patients. The ADC value was significantly higher in renal cell carcinoma (RCC) than in transitional cell carcinoma (2.71+/-2.35 x 10(-3) mm(2) s(-1) vs 1.61+/-0.80 x 10(-3) mm(2) s(-1); p = 0.022). While analysing the histological subtypes of RCC, a significant difference in ADC values between clear cell carcinoma and non-clear cell carcinoma was found (1.59+/-0.55 x 10(-3) mm(2) s(-1) vs 6.72+/-1.85 x 10(-3) mm(2) s(-1); p = 0.0004). Similarly, ADC values of RCC revealed a significant difference between positive and negative metastatic lesions (1.06+/-0.38 x 10(-3) mm(2) s(-1) vs 3.02+/-2.44 x 10(-3) mm(2) s(-1); p = 0.0004), whereas intensity on T(1) and T(2) weighted imaging did not reach statistical significance. In conclusion, DWI has clinical value in the characterisation of renal carcinomas and could be applied in clinical practice for their management.

Hepatocyte Response to Continuous Low Dose-rate Radiation in Radioimmunotherapy Assessed by Micronucleus Assay

The response of hepatocytes to low dose-rate irradiation was examined in mice following the injection of radiolabelled monoclonal antibody. Mice were injected intravenously with an 131I-labelled monoclonal antibody 196-14 which recognizes CA125 antigen, and the effect of continuous low dose-rate irradiation on hepatocytes was assessed using the micronucleus assay. The frequency of micronuclei increased in a dose-dependent fashion, but it was lower than the frequency induced by conventional external X-rays which was determined immediately after the irradiation. A linear quadratic model (micronucleus frequency = aD+bD2+c) showed that the value of b decreased with low dose-rate irradiation from the radiolabelled antibody. It is concluded that the micronucleus assay is useful for the evaluation of the response of hepatocytes to irradiation in radioimmunotherapy.

Regeneration of central nervous tissue using a collagen scaffold and adipose-derived stromal cells

Adipose-derived stromal cells (ASCs) include stem cells, which have the potential to differentiate into a variety of cell lineages. The regeneration of central nerves was examined using ASCs and a collagen scaffold. A cerebral cortex defect (3 x 4 x 3 mm(3)) was created in the left frontal lobe of 16 male rats. In one group (n = 8), collagen (3 x 4 x 3 mm(3)) seeded with DiI-labeled ASCs was implanted in the defect. In order to seed the ASCs, a combination of the rotary cell culture system and pressing the collagen scaffold gently several times with a glass rod was applied. In the control group (n = 8), collagen was implanted without ASCs. The rats were sacrificed at 1 month after the scaffold implantation. Histologically, 0.2% of the implanted ASCs were positive for anti-human/rat microtubule-associated protein 2 (MAP2) antibody and microvessels were present at a density of 4.6 +/- 1.2/mm(2) within the collagen scaffold-implanted area in each coronal section. In the control group, no MAP2-positive cells were detected and the microvessel density was 0.6 +/- 0.4/mm(2). These data suggest that ASCs seeded into a collagen scaffold may have the potential to promote regeneration of nervous tissue after cerebral cortex injury.

The prognostic impact of hypoxia-inducible factor-1α and VEGF, IGF-2, p21, p53 expression in gastric adenocarcinoma

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Background: Hypoxia caused by either radiation or chemotherapy induces various intracellular adaptive responses, which contribute to tumor progression. The clinicopathological characteristics of human gastric cancer and the clinical outcomes were analyzed to investigate the effects of the expression of hypoxia-inducible factor1α (HIF-1α) and some related proteins, such as, vascular endothelial growth factor (VEGF), insulin-like growth factor-2 (IGF-2), p21, and p53 on the prognosis of human gastric cancer. Methods: The expressions of HIF-1α, VEGF, IGF-2, p21, and p53 proteins were determined by immunohistochemistry in 216 specimens of primary gastric cancer. Results: Of all 216 patients, 85 (39.4%) showed a positive expression of HIF-1α. In addition, the HIF-1α expression positively correlated with the tumor size and depth of invasion, while it was also more frequent in tumors with lymphatic invasion and undifferentiated adenocarcinomas. Though the VEGF expression significantly correlated with the HIF-1α expression, the expressions of IGF-2, p21 and p53 did not show any correlation. HIF-1α-positive/p21-negative tumors had a lower apoptotic index, and the patients with such tumors also had a significantly poorer prognosis. Similarly, HIF-1α-positive/p53-positive tumors had a significantly poorer prognosis. A multivariate Cox regression analysis showed the depth of invasion, lymph node metastasis, and HIF-1α positivity to all be independent prognostic factors in patients with gastric cancer. Conclusions: Based on the above findings, HIF-1α is therefore considered to be a useful independent prognostic factor in gastric cancer, and the combination of a HIF-1α protein overexpression with the loss of p21 expression or nonfunctional p53 thus tends to indicate a dismal prognosis. Controlling hypoxia, especially in the HIF-1α pathways, may therefore hold the key to a greater individualization of therapy and also lead to the development of new treatments for patients with gastric cancer.

No significant financial relationships to disclose.

In situ tissue engineering for tracheal reconstruction using a luminar remodeling type of artificial trachea

BACKGROUND

After successful trials of tracheal reconstruction using mesh-type prostheses in canine models, the technique has been applied clinically to human patients since 2002. To enhance tissue regeneration, we have applied a new tissue engineering approach to this mesh-type prosthesis.

METHODS

The prosthesis consists of a polypropylene mesh tube reinforced with a polypropylene spiral and atelocollagen layer. The cervical tracheas of 18 beagle dogs were replaced with the prosthesis. The collagen layer was soaked with peripheral blood in 6 of the dogs, with bone marrow aspirate in another 6, and with autologous multipotential bone marrow-derived cells (mesenchymal stem cells) in another 6. The dogs were humanely killed at 1 to 12 months after the operation.

RESULTS

All 18 dogs survived the postoperative period. Bronchoscopically, 3 of 4 dogs in the peripheral blood group showed stenosis, whereas no stenosis was evident in all 8 of the dogs in the bone marrow and mesenchymal stem cell groups 6 months after the operation. Faster epithelialization and fewer complications, such as mesh exposure and luminal stenosis, were observed in these two groups than in the peripheral blood group. Histologically, the cells from autologous bone marrow were found to proliferate into the tracheal tissue during the first month. Cilial movement in these two groups was faster than that in the peripheral blood group and recovered to 80% to 90% of the normal level.

CONCLUSIONS

Bone marrow aspirate and mesenchymal stem cells enhance the regeneration of the tracheal mucosa on this prosthesis. This in situ tissue engineering approach may facilitate tracheal reconstruction in the clinical setting.

Prediction of Functional Outcome in Stunned Myocardium after Myocardial Infarction using BMIPP and Tetrofosmin Imaging

The predictive value of combined 123iodine-labelled 15-( p-iodophenyl)-3 R,S-methyl pentadecanoic acid imaging (123I-BMIPP) and early technetium-99m (99mTc)-tetrofosmin imaging was compared with combined 123I-BMIPP and delayed 99mTc-tetrofosmin or 123I-BMIPP and thallium-201 (201Tl) imaging for functional outcome of stunned myocardium after acute myocardial infarction (AMI) in 37 patients with AMI. All patients underwent successful percutaneous coronary intervention with/without stenting within 24 h of symptoms. Resting 201Tl, 99mTc-tetrofosmin and 123I-BMIPP imaging were performed within 10 days of hospital admission; 99mTc-tetrofosmin imaging was also performed 6 months later. Segments were mismatched when the 123I-BMIPP score was greater than the 99mTc-tetrofosmin or 201Tl scores, and were matched when all scores were the same. Left ventricular function was estimated using wall motion score. Sensitivity and regional wall motion were significantly better in mismatching 99mTc-tetrofosmin-early/123I-BMIPP segments than mismatching 201Tl/123I-BMIPP or 99mTc-tetrofosmin-delayed/123I-BMIPP segments. It is concluded that mismatching of 123I-BMIPP and early 99mTc-tetrofosmin uptake can predict improvement in wall motion of stunned myocardium better than the other two imaging combinations.

Expansion of radiofrequency ablation volume by saturated NaCl saline injection in the area of vaporization

BACKGROUND

Vaporization around the radiofrequency (RF) electrode after RF application (RFA) limits the RF ablation area.

PURPOSE

To determine whether saturated saline injected into the area of vaporization after initial RFA extends ablation area after further RFA.

MATERIAL AND METHODS

RFA was performed in 18 ex vivo porcine livers and four in vivo rabbit erector spinae muscles. An RF electrode was used to ablate an area with 40W of parallel current for 15 min. The ablation margin was determined using a thermocouple, and the radius of the ablated area was measured. After RF electrode removal, saturated saline was infused through a percutaneous ethanol injection needle into the site of the original RFA in 11 liver samples and two erector spinae muscles. Three minutes later, RFA was resumed for 15 min. The remaining seven control liver samples and two spinae muscles received RFA without saline injection. The radius of the final ablated area was then measured.

RESULTS

In the ex vivo study, injection of saturated saline significantly decreased tissue impedance (87.7+/-9.4 to 51.1+/-9.7 Omega, P<0.0001), and increased the mean radius of the ablated area (15.9+/-3.0 to 25.0+/-3.6 mm, P<0.0001). These significant changes were not observed without injection of saturated saline. Similar trends were found in the in vivo study.

CONCLUSION

Injection of saturated saline into the area of vaporization around the RF electrode, followed by additional RFA, caused concentric expansion of the final ablation area, facilitating more efficient tumor ablation.

HLA-DRB1 alleles influence clinical phenotypes in Japanese patients with ulcerative colitis

The human leukocyte antigen (HLA) region has been implicated in the disease susceptibility of inflammatory bowel disease by several linkage and association studies. In Caucasians, HLA-DRB1 has been reported to determine the clinical phenotypes of ulcerative colitis (UC). Others and we previously reported that HLA-DRB1*1502 was strongly associated with UC in the Japanese population. However, the contribution of HLA-DRB1 to the clinical phenotypes in Japanese UC has not been elucidated yet. The aim of this study was to determine whether HLA-DRB1 alleles were associated with the clinical phenotypes in Japanese patients with UC. A total of 353 patients with UC were recruited. Patients were classified into subgroups by sex, age at diagnosis, disease extent, need for steroid therapy or need for surgical treatment. The allele frequency of HLA-DRB1*08 was significantly higher in patients whose disease extended beyond the rectum (left-sided and extensive UC) than in those with proctitis [odds ratio (OR)=2.20, Pc=0.043). The allele frequency of HLA-DRB1*09 was significantly higher in patients with UC diagnosed at the age of 40 years or older than in those with UC diagnosed before the age of 40 years (OR=2.31, Pc=0.022). Besides these positive associations, no significant differences were found in the allele frequencies between the other subgroups. We conclude that HLA-DRB1*09 is associated with the age at diagnosis and HLA-DRB1*08 is associated with the disease extent of UC in Japanese. These results indicate that HLA-DRB1 is not only associated with the overall UC susceptibility but also associated with the clinical phenotypes in Japanese.

Relationship between age at onset and magnetic resonance image-defined hyperintensities in mood disorders

OBJECTIVES

To examine in patients with mood disorders the relationship of age at onset with the location and degree of MRI-defined brain hyperintensities.

METHOD

Fifty-two patients diagnosed as having mood disorders and 14 controls participated in the study. Brain MR images were analyzed according to semiquantitative ratings for the anatomical distribution and severity of T2-weighted hyperintensities. We compared these hyperintensities among the three age- and sex-matched groups of late-onset mood disorder patients (LOM), early-onset mood disorder patients (EOM), and controls. The time since the onset of disorder was significantly longer in the EOM than in the LOM group. We also conducted linear multiple regression analysis using the severity of hyperintensities as dependent variable to determine whether the clinical features correlate with vascular pathology.

RESULTS

As for deep white matter hyperintensity (DWMH), LOM exhibited higher ratings than EOM; as for brain areas, significant between-group differences were detected in the bilateral frontal areas and in the left parieto-occipital area. No significant difference was observed between EOM and controls. As for periventricular hyperintensity, there was no difference among the three groups. We obtained a significant regression model to predict DWMH ratings; age, number of ECTs, and LOM were selected as significant variables.

CONCLUSION

The present study suggests that the time since the onset of disorder does not affect the development of white matter lesions, but that white matter lesions are associated with late-onset mood disorders. The frontal areas and the left parieto-occipital area would be important for the development of late-onset mood disorders.

Relativistic laser channeling in plasmas for fast ignition

We report an experimental observation suggesting plasma channel formation by focusing a relativistic laser pulse into a long-scale-length preformed plasma. The channel direction coincides with the laser axis. Laser light transmittance measurement indicates laser channeling into the high-density plasma with relativistic self-focusing. A three-dimensional particle-in-cell simulation reproduces the plasma channel and reveals that the collimated hot-electron beam is generated along the laser axis in the laser channeling. These findings hold the promising possibility of fast heating a dense fuel plasma with a relativistic laser pulse.

Brain metabolic changes associated with predispotion to onset of major depressive disorder and adjustment disorder in cancer patients--a preliminary PET study

OBJECTIVES

To explore neurobiological risk factors for major depressive disorder (MDD) and adjustment disorder in cancer patients by examining regional brain metabolism before psychiatric manifestation using positron emission tomography and by prospectively observing depressive and anxiety symptoms.

METHOD

Cancer patients who showed no psychiatric symptoms when they underwent 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) were followed up for one year using the Hospital Anxiety and Depression Scale (HADS). Fourteen patients who showed high HADS scores and 14 patients who showed low HADS scores were assessed by a psychiatrist 2 years after the PET scan and grouped into the deterioration group (n=10) and the no-change group (n=9). 18F-FDG PET images were analyzed to examine the difference in local brain glucose metabolism between the two groups.

RESULTS

The deterioration group showed a decreased glucose metabolism in the right medial frontal gyrus (BA6) and an increased glucose metabolism in the right posterior cingulate (BA29), right anterior cingulate (BA25), left subcallosal gyrus (BA25), and left caudate compared with the no-change group.

CONCLUSION

Cancer patients who later developed MDD or adjustment disorder showed regional brain metabolic changes. These regions may be associated with vulnerability to the onset of MDD or adjustment disorder in cancer patients.

A new 3-D diagnosis strategy for duodenal malignant lesions using multidetector row CT, CT virtual duodenoscopy, duodenography, and 3-D multicholangiography

Recent advances in multidetector row computed tomography (MD-CT) technology provide new opportunities for clinical diagnoses of various diseases. Here we assessed CT virtual duodenoscopy, duodenography, and three-dimensional (3D) multicholangiography created by MD-CT for clinical diagnosis of duodenal malignant lesions. The study involved seven cases of periduodenal carcinoma (four ampullary carcinomas, two duodenal carcinomas, one pancreatic carcinoma). Biliary contrast medium was administered intravenously, followed by intravenous administration of an anticholinergic agent and oral administration of effervescent granules for expanding the upper gastrointestinal tract. Following intravenous administration of a nonionic contrast medium, an upper abdominal MD-CT scan was performed in the left lateral position. Scan data were processed on a workstation to create CT virtual duodenoscopy, duodenography, 3D multicholangiography, and various postprocessing images, which were then evaluated for their effectiveness as preoperative diagnostic tools. Carcinoma location and extent were clearly demonstrated as defects or colored low-density areas in 3-D multicholangiography images and as protruding lesions in virtual duodenography and duodenoscopy images. These findings were confirmed using multiplanar or curved planar reformation images. In conclusion, CT virtual duodenoscopy, doudenography, 3-D multicholangiography, and various images created by MD-CT alone provided necessary and adequate preoperative diagnostic information.

Measurement and calculation of the differential reflectance spectrum of hydrogen-terminated silicon surfaces having different crystal orientations

The differential reflectance spectrum between the (001) and the (111) hydrogen-terminated Si surfaces without native oxidation is investigated. Careful measurements using developed apparatus and an ultra-clean process are performed. The measured spectrum is compared with the reported one (Chongsawangvirod and Irene 1991 J. Electrochem. Soc. 138 1748-52), and is shown to be roughly identical even though a native oxidation effect exists. The theoretical calculation based on density-functional theory (DFT) and local density approximation (LDA) is also performed. The peak positions in the calculated and the measured spectra are in good accordance with each other, while the magnitudes of the peaks are in relatively worse agreement. Although the inclusion of advanced approximations would provide more accurate results, a qualitative reproduction is achieved in this study as well. It is concluded that the origin of the spectrum is mainly in the deformation of the bulk states induced by surface perturbation.

Pure word deafness and pure anarthria in a patient with frontotemporal dementia

A 66-year-old right-handed man developed pure anarthria following pure word deafness. In addition to language disorders, his behavior gradually changed and finally included violence against his wife. Brain magnetic resonance imagings revealed atrophy of the left perisylvian area, which included the inferior half of the precentral gyrus and the upper portion of the superior temporal gyrus, consistent with frontotemporal dementia (FTD). It has been documented as either a disorder of expressive language or as an impaired understanding of word meaning. Unlike with pure anarthria, pure word deafness is not included in the clinical diagnostic current criteria for FTD. However, a large variety of language symptoms can appear in FTD according to the distribution of pathological changes in the frontotemporal cortices. This case suggests that pure word deafness could be a prodomal symptom of FTD.

Experimental repair of phrenic nerve using a polyglycolic acid and collagen tube

OBJECTIVE

The feasibility of a nerve guide tube for regeneration of the phrenic nerve with the aim of restoring diaphragmatic function was evaluated in a canine model.

METHODS

The nerve tube, made of woven polyglycolic acid mesh, had a diameter of 3 mm and was filled with collagen sponge. This polyglycolic acid-collagen tube was implanted into a 10-mm gap created by transection of the right phrenic nerve in 9 beagle dogs. The tubes were implanted without a tissue covering in 5 of the 9 dogs (group I), and the tubes were covered with a pedicled pericardial fat pad in 4 dogs (group II). Chest x-ray films, muscle action potentials, and histologic samples were examined 4 to 12 months after implantation.

RESULTS

All of the dogs survived without any complications. x-ray film examination showed that the right diaphragm was paralyzed and elevated in all dogs until 3 months after implantation. At 4 months, movement of the diaphragm in the implanted side was observed during spontaneous breathing in 1 dog of group I and in 3 dogs of group II. In the dogs showing diaphragm movement, muscle action potentials were evoked in the diaphragm muscle, indicating restoration of nerve function. Regeneration of the phrenic nerve structure was also examined on the reconstructed site using electron microscopy.

CONCLUSION

The polyglycolic acid-collagen tube induced functional recovery of the injured phrenic nerve and was aided by coverage with a pedicled pericardial fat pad.