Effect of iodine concentration and body size on iodine subtraction in virtual non-contrast imaging: A phantom study.

INTRODUCTION: Dual-energy computed tomography (DECT) can generate virtual non-contrast (VNC) images. Herein, we sought to improve the accuracy of VNC images by identifying the optimal slope of contrast media (SCM) for VNC-image generation based on the iodine concentration and subject's body size. METHODS: We used DECT to scan a multi-energy phantom including four iodine concentration rods (15, 10, 5, and 2 mg/mL), and 240 VNC images (eight SCM ranging from 0.49 to 0.56 × three body sizes × ten scans) that were generated by three-material decomposition. The CT number of each iodine and solid water rod part was measured in each VNC image. The difference in the CT number between the iodine and the solid water rod part was calculated and compared using paired t-test or repeated measures ANOVA. RESULTS: The SCM that achieved an absolute value of the difference in CT number of <5.0 Hounsfield units (HU) for all body sizes simultaneously was greater at lower iodine concentration (SCM of 0.5, 0.51, and 0.53 at 10, 5, and 2 mg/mL iodine, respectively). At an iodine concentration of 15 mg/mL, no SCM achieved an absolute difference of <5.0 HU in CT number for all body sizes simultaneously. At all iodine concentrations, the SCM achieving the minimal difference in the CT number increased with the increase in body size. CONCLUSION: By adjusting the SCM according to the iodine concentration and body size, it is possible to generate VNC images with an accuracy of <5.0 HU. IMPLICATIONS FOR PRACTICE: Improving the accuracy of VNC images minimizing incomplete iodine subtraction would make it possible to replace true non-contrast (TNC) images with VNC images and reduce the radiation dose.

Overexpression of O-GlcNAc by prostate cancer cells is significantly associated with poor prognosis of patients.

BACKGROUND: O-linked ß-N-acetylglucosamine (O-GlcNAc) is a glycan essential for fundamental cellular processes such as transcription/translation, nuclear transport, protein stability and protein-protein interactions. However, the role of O-GlcNAc in prostate cancer progression of patients remains poorly unknown. Here we investigated the clinicopathological significance of O-GlcNAc expression level in prostate cancer. METHODS: O-GlcNAc expression level in prostate cancer cells was determined by immunohistochemistry of prostate biopsy specimens obtained from 56 patients later treated with hormone deprivation therapy comparing with adjacent normal prostate glands in the same sections. Overall survival was determined by the Kaplan-Meier and Cox proportional hazards methods with univariate and multivariate models. The effects of reduced O-GlcNAc expression level on proliferation and invasion of prostate cancer LNCaP cells were examined using small interfering RNA (siRNA) targeting O-GlcNAc transferase (OGT), the enzyme responsible for O-GlcNAc biosynthesis. RESULTS: Defining cancer cells showing stronger cytoplasmic staining than normal prostate glands as overexpression of O-GlcNAc, 39% of prostate cancer patients were categorized as overexpression. The Kaplan-Meier and Cox proportional hazards methods with univariate model analysis revealed that O-GlcNAc overexpression was associated with overall survival (P=0.0012 for the Kaplan-Meier and P=0.0021 for Cox univariate hazard model analysis). Furthermore, O-GlcNAc was the only item in which a significant difference was observed at overall survival by multivariate analysis (P=0.0475). Finally, siRNA-mediated OGT knockdown in LNCaP cells resulted in decreased expression of O-GlcNAc and promoted decreased proliferation and tumor cell invasion compared with control siRNA-transfected LNCaP cells. CONCLUSIONS: These results indicate that O-GlcNAc expression level in prostate cancer cells is associated with poor prognosis of prostate cancer patients and likely enhances tumor cell proliferation and invasion.

Photodynamic therapy plus regulatory T-cell depletion produces immunity against a mouse tumour that expresses a self-antigen.

BACKGROUND: Photodynamic therapy (PDT) can lead to development of antigen-specific immune response and PDT-mediated immunity can be potentiated by T regulatory cell (Treg) depletion. We investigated whether the combination of PDT with cyclophosphamide (CY) could foster immunity against wild-type tumours expressing self-antigen (gp70). METHODS: Mice with CT26 tumours were treated with PDT alone or in combination with low-dose CY. T regulatory cell numbers and transforming growth factor-ß (TGF-ß) levels were measured at several time points after treatment. Mice cured by PDT+CY were rechallenged with CT26 and monitored for long-term survival. RESULTS: Photodynamic therapy+CY led to complete tumour regression and long-term survival in 90% of treated mice while the absolute numbers of Treg decreased after PDT+CY and the TGF-ß levels were reduced to a level comparable to naïve mice. Sixty-five percent of the mice treated with PDT+CY that survived over 90 days tumour free rejected the rechallenge with the same tumour when a second dose of CY was administered before rechallenge but not without. CONCLUSION: Administration of CY before PDT led to depletion of Treg and potentiated PDT-mediated immunity, leading to long-term survival and development of memory immunity that was only uncovered by second Treg depletion.

Development of a phase contrast imaging system based on a yttrium aluminum garnet laser with folded beam for observations of density fluctuations in compact helical system.

A near-infrared laser phase contrast optical system incorporating a folded beam was developed in order to measure the distribution of density fluctuations in a high-temperature plasma. The coherent light source used was an yttrium aluminum garnet laser stabilized by a ring oscillator. The probe beam system separates and reflects the incident and exiting beams with a polarizer and a fully reflective mirror with a waveplate. This system was employed with a compact helical system to detect fluctuations at the plasma edge.

Haematological data for Matsumoto Eosinophilic Shinshu rats as determined by an automated haematology analyser.

The Matsumoto Eosinophilic Shinshu (MES) rat originated from an inbred mutant colony of rats with spontaneous eosinophilia. As part of an investigation of the pathogenesis of the MES rat, we examined the haematology data for 106 males and 88 females and age-associated changes using an automated haematology analyser, flow cytometric analysis and morphological examination. The data at 10 weeks of age showed the MES rats had higher counts for eosinophils and neutrophils, slightly higher counts for lymphocytes, monocytes, basophils, and large unstained cells (LUCs), and slightly lower values for the erythrocytic parameters when compared with Sprague-Dawley (SD) rats. In data for MES rats aged 8 to 20 weeks, eosinophil counts increased with age up to 20 weeks together with some increased neutrophil counts. After 11 weeks of age, counts for lymphocytes, monocytes, basophils, and LUCs in the MES rats were also slightly increased. In female MES rats, flow cytometric analysis showed increased counts for pan-T+ cells, but blasts, abnormal granulocytes and lymphocytes were not detected morphologically. The MES rat characterized by the haematological findings could be a useful animal model for studies of hypereosinophilia.

Anterior cruciate ligament reconstruction and physiological joint laxity: earliest changes in joint stability and stiffness after reconstruction.

Physiological joint laxity is an important element of normal knee joint function, providing smooth joint movement. However, the objective evaluation of post-operative results after knee ligament surgery is usually based primarily on stability and range of motion, and joint laxity has been ignored. In this study, we measured the joint stiffness of 82 knees undergoing anterior cruciate ligament (ACL) reconstruction with the Leeds-Keio artificial ligament, before the operation, immediately after the operation, and finally when the full range of motion was achieved postoperatively; changes in joint laxity after the ACL reconstruction were investigated. Before the operation, joint laxity was greater than that of the normal side (P < 0.01), but immediately after the operation it diminished compared not only with that observed preoperatively, but also with that of the normal side. When the full range of motion was achieved, joint laxity was lower than that observed immediately after the operation (P < 0.01), but still remained higher than that of the normal side (P < 0.01). In other words, stability was achieved, but joint laxity was diminished through the operation. In this series, a stiffer artificial ligament than the natural ACL was used, and maximum tension was applied during the operation, aiming at better stability, but this may cause diminution of joint laxity.

Extensive post-traumatic ossification of the patellar tendon. A report of two cases.

Two men, aged 21 and 50 years, were seen with ossification of the patellar tendon after injury to the knee in adolescence. They complained of pain and had patella alta. Large bony masses were excised from below the affected patellae. The patellar tendon was then reconstructed using a Leeds-Keio ligament. The results at six and ten years, respectively, were good, with neither patient having pain or an extension lag.

Radiographic changes in the patella after total knee arthroplasty without resurfacing the patella. Comparison of osteoarthrosis and rheumatoid arthritis.

The necessity of patellar resurfacing has aroused considerable controversy. Between 1986 and 1996, we have routinely performed 208 primary total knee arthroplasties (TKAs) without resurfacing the patella. However, we have occasionally observed gradual postoperative patellar deterioration which caused peripatellar pain. This study observed the radiographic changes in the patella after TKA without resurfacing the patella to assess the effect of the changes on the clinical results. Sixty out of 208 TKAs were assessed in this study. The original diagnoses were osteoarthrosis (OA) in 17 joints and rheumatoid arthritis (RA) in 43 joints. Fourteen patients (23.3%) complained of postoperative peripatellar pain: 2 of the 17 patients with OA (11.8%) and 12 of the 43 with RA (27.9%). Lateral tilt of the patella slightly decreased with time, but lateral shift increased slightly. Patellar length and width increased throughout the follow-up period. The thickness of the patella, especially in the RA cases, significantly (Mann-Whitney, p < 0.05) decreased with time. According to these radiographic findings, as time passed the thickness of the patella decreased, its length and width increased, and the patella as a whole became flattened. On examining the effect of this flattening on postoperative pain, it was found that about 70% of those patients whose patellar thickness had decreased to 80% or less complained of peripatellar pain. In the case of the OA patients, however, there was no statistically significant correlation between patellar flattening and pain. It is concluded that patellar resurfacing should be considered for the patient with rheumatoid arthritis. Because patellar flattening did not develop in many patients with OA and few of them complained of peripatellar pain, patellar resurfacing should not be performed routinely.

Age-dependent alteration of the serum-unbound fraction of nicardipine, a calcium-channel blocker, in man.

To determine whether the age-dependent increase in the pharmacological effect of calcium-channel blockers is a result of age-dependent alteration of the unbound fraction the drug in serum, the unbound fraction of the nicardipine was investigated in the serum of 38 adults. The unbound concentration of nicardipine in serum to which nicardipine (205.4 ng mL-1) had been added was determined by ultracentrifugation to range from 0.49 to 4.01% (mean +/- s.d., 1.55 +/- 0.78%). Non-glycosylated albumin was most strongly correlated with age (r = 0.901). Total bilirubin was weakly correlated with age whereas levels of alpha-1-acid glycoprotein, triglycerides and glycosylated albumin were not correlated with age. A significant (P < 0.01) linear correlation was obtained between the unbound fraction of nicardipine and parameters such as age, albumin, albumin/globulin ratio, albumin/glycosylated albumin ratio, non-glycosylated albumin and total bilirubin. To assess the relative effect of each variable on the unbound fraction of nicardipine, stepwise multiple linear regression was performed using age and biochemical parameters. The three variables (non-glycosylated albumin, total bilirubin and age) were entered into the regression equation. The results of this study showed that the major ligand of nicardipine in serum was non-glycosylated albumin, which decreased with age. It was, moreover, shown that the serum-unbound concentration of nicardipine increased with age. This finding would be one factor accounting for the increase in the pharmacological effect of nicardipine with age. In addition, our predicted model for the unbound fraction of nicardipine might be useful in determining the appropriate nicardipine dose for the elderly.

[An experimental study on tissue induction in anterior cruciate ligament reconstruction with the scaffold-type polyester artificial ligament (Leeds-Keio)].

The effect of experimental autogenous tissue implantation (infrapatellar fat pad, fascia lata) together with scaffold type artificial ligament (Leeds-Keio) in ACL reconstruction was studied in 56 mongrel adult dogs. Specimens were examined macroscopically, histologically and by means of microangiography. The results were compared with those in which the artificial ligament was used alone. When infrapatellar fat pad was transferred on artificial ligament, tissue induction was observed 2 weeks after reconstruction. When ACL was reconstructed using a combination of artificial ligament and a small piece of fascia lata, maturated dense collagen fibers were observed 24 weeks after reconstruction. These results indicated that quicker tissue induction could be obtained in ACL reconstruction using an artificial ligament together with a infrapatellar fat pad, and that collagen fiber maturation was accelerated when ACL was reconstructed using an artificial ligament together with a small piece of fascia lata.

[The application of industrial endoscope to observation of the ocular-fundus in small laboratory animals].

Observation and recording methods of the ocular-fundus in small laboratory animals were studied using the industrial endoscope and VTR systems, respectively. The ocular-fundus was observed widely, brightly and clearly in the usual animal facility. In addition, the ocular-fundus was recorded easily and it was possible to examine the ocular-fundus recorded by the VTR systems.