The use of sonication treatment to completely decellularize blood arteries: a pilot study

We have developed a novel sonication decellularization system to prepare completely decellularized bioscaffolds in a short treatment time. The aim of the study is to investigate the sonication decellularization efficiency and its relation with ultrasonic power output and dissolved oxygen (DO) concentration in different detergent solution. In the study, we used aorta samples to evaluate sonication decellularization efficiency, which assessed treatment duration, sonication power and SDS detergent with/without saline. The treated samples were evaluated histologically by Hematoxylin Eosin (HE) staining and scanning electron microscopic (SEM) photographs. The concentration of DO was monitored to identify the effect of sonication on cavitation-related DO concentration in the solution. From histological results, the sonication decellularization efficiency was better than the other preparation methods. Decellularization efficiency was tended to increase significantly when DO value decreasing after 6 hours of treatment. In conclusion, we conclude that sonication treatment can be used to prepare the complete decellularized scaffolds in short treatment time.

Cross-sectional study on respiratory effect of toner-exposed work in manufacturing plants, Japan: pulmonary function, blood cells, and biochemical markers

The aim of the study is to examine the relationship between toner-exposed work and health indices related to respiratory disorders and to confirm the baseline of a cohort study to clarify the effect of toner exposure in manufacturing plants. Subjects were 1614 male workers (809 toner-exposed workers and 805 referents) who were engaged in toner manufacturing plants in Japan (Fuji Xerox Co., Ltd). The age of subjects was from 19 to 59 years, and the average age was 40.2 years(median 40 years, SD 7.67). We conducted a pulmonary function test (PEFR, VC, FVC, FEV(1.0)%, V25/Ht) and a blood cell test (RBC, Hb, Hct, Plt, WBC, cell contents of WBC) and measured biochemical indices in blood (ALT, AST, gamma-GTP, CRP, IgE) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in urine. Student t-test and logistic regression analysis were applied to compare between the toner-exposed workers and the referents and to analyze the relationship among indices of effects and independent factors. There was no significant difference between the two groups in blood cell count and biochemical indices. Inflammation- and allergy-related markers such as 8OHdG and IgE also showed no significant difference between toner-exposed workers and the referents. The influence of smoking on pulmonary function indices was observed, but there was no relationship between the pulmonary function and toner-exposed work. In this article, we report a preliminary cross-sectional analysis in the subjects of a cohort study. No difference in pulmonary function indices was observed between the toner-exposed workers and the referents, and there was no consistent relationship between the exposure status and examined indices; however, the prevalence of subjective respiratory symptoms was higher in the exposed workers as presented in another report. Further analysis is important in the ongoing cohort study to clarify the effect of toner exposure on respiratory systems.

Endoscopic submucosal dissection for colorectal tumors: technical difficulties and rate of perforation

BACKGROUND AND STUDY AIM

Endoscopic submucosal dissection (ESD) for colorectal tumors is not generally recommended because of the technical difficulties and complications, including perforation. These aspects of ESD are thoroughly analyzed in our retrospective study.

PATIENTS AND METHODS

We studied 105 colorectal tumors, from 100 patients, that were treated by ESD at the Kyoto Prefectural University of Medicine or Nara City Hospital between 2005 and 2008. We analyzed tumor size, operation time, rate of en bloc resection, and complications. In addition, we thoroughly investigated the cases of perforation.

RESULTS

The average tumor size was 30.4 mm; average operation time, 102 min; and rate of en bloc resection, 88.5 %. Perforation occurred in 10.4 % of the ESD procedures. Of the 11 perforations, 8 were detected during ESD and treated by clip closure during endoscopy, while 3 were evident only on subsequent routine computed tomography (CT); these were also managed conservatively. A case of postoperative hemorrhage was also observed.

CONCLUSIONS

ESD effectively achieved a high rate of en bloc resection. However, the perforation rate was substantial; hence, improvement in the ESD method is required. The outcomes of ESD, especially for early colorectal malignancies, need to be assessed further.

Small salivary gland size in patients with xerostomia of unknown etiology

OBJECTIVE

We have recently reported that flow rates of whole saliva in young healthy humans correlate positively with salivary gland sizes. The low rate of salivary secretion in xerostomia patients may be related to the small size of the salivary glands. To investigate this possibility, relationships between salivary secretions and salivary gland sizes were investigated in unknown-etiology xerostomia patients and healthy controls.

DESIGN

The sizes of the three major salivary glands in seven xerostomia patients and seven age- and gender-matched healthy controls who have no previous disease history and prescription medication related to xerostomia, were measured by use of a magnetic resonance imaging technique. The salivary glands of all subjects failed to show any pathological aspects in magnetic resonance images. The flow rates of unstimulated and chewing-stimulated whole saliva were also measured.

RESULTS

Flow rates of unstimulated and chewing-stimulated whole saliva and the sizes of the parotid and submandibular glands were significantly lower and smaller in xerostomia patients of unknown etiology when compared with healthy controls. In addition, salivary flow rates per size of the combined three major salivary glands were also significantly lower in the xerostomia patients of unknown etiology.

CONCLUSIONS

The smaller salivary gland size in xerostomia patients of unknown etiology may be one of the causes of the reduced salivary secretion. The secretion rates as a function of gland sizes were also lower, and so it is likely that functional impairments of the salivary gland are also present in patients with xerostomia of unknown etiology.

A new PET scanner with semiconductor detectors enables better identification of intratumoral inhomogeneity

An autoradiography method revealed intratumoral inhomogeneity in various solid tumors. It is becoming increasingly important to estimate intratumoral inhomogeneity. However, with low spatial resolution and high scatter noise, it is difficult to detect intratumoral inhomogeneity in clinical settings. We developed a new PET system with CdTe semiconductor detectors to provide images with high spatial resolution and low scatter noise. Both phantom images and patients' images were analyzed to evaluate intratumoral inhomogeneity.

METHODS

This study was performed with a cold spot phantom that had 6-mm-diameter cold sphenoid defects, a dual-cylinder phantom with an adjusted concentration of 1:2, and an "H"-shaped hot phantom. These were surrounded with water. Phantom images and (18)F-FDG PET images of patients with nasopharyngeal cancer were compared with conventional bismuth germanate PET images. Profile curves for the phantoms were measured as peak-to-valley ratios to define contrast. Intratumoral inhomogeneity and tumor edge sharpness were evaluated on the images of the patients.

RESULTS

The contrast obtained with the semiconductor PET scanner (1.53) was 28% higher than that obtained with the conventional scanner (1.20) for the 6-mm-diameter cold sphenoid phantom. The contrast obtained with the semiconductor PET scanner (1.43) was 27% higher than that obtained with the conventional scanner (1.13) for the dual-cylinder phantom. Similarly, the 2-mm cold region between 1-mm hot rods was identified only by the new PET scanner and not by the conventional scanner. The new PET scanner identified intratumoral inhomogeneity in more detail than the conventional scanner in 6 of 10 patients. The tumor edge was sharper on the images obtained with the new PET scanner than on those obtained with the conventional scanner.

CONCLUSION

These phantom and clinical studies suggested that this new PET scanner has the potential for better identification of intratumoral inhomogeneity, probably because of its high spatial resolution and low scatter noise.