Computed Tomography-Based Evaluation of Volume and Position Changes of the Target Region and Organs at Risk During Radiotherapy for Esophageal Cancer: A Pilot Study.

OBJECTIVE: To analyze changes in volume and position of target regions and organs at risk (OARs) during radiotherapy for esophageal cancer patients. METHODS: Overall, 16 esophageal cancer patients who underwent radiotherapy, including 10 cases of intensity-modulated radiation therapy (IMRT) and six of three-dimensional conformal radiotherapy (3D-CRT), were enrolled. The prescription doses for the planning target volumes (PTVs) were as follows: PTV1, 64 Gy/32 fractions; and PTV2, 46 Gy/23 fractions. Repeat computed tomography (CT) was performed for patients after the 5th, 10th, 15th, 20th, and 25th fractions. Delineation of the gross tumor volume (GTV) and OAR volume was determined using five repeat CTs performed by the same physician. The target and OAR volumes and centroid positions were recorded and used to analyze volume change ratio (VCR), center displacement (ΔD), and changes in the distance from the OAR centroid positions to the planned radiotherapy isocenter (distance to isocenter, DTI) during treatment. RESULTS: No patient showed significant changes in target volume (TV) after the first week of radiotherapy (five fractions). However, TV gradually decreased over the following weeks, with the rate slowing after the fourth week (40 Gy). The comparison of TV from baseline to 40 Gy (20 fractions) showed that average GTVs decreased from 130.7 ± 63.1 cc to 92.1 ± 47.2 cc, with a VCR of -29.21 ± 13.96% (p<0.01), while the clinical target volume (CTV1) decreased from 276.7 ± 98.2 cc to 246.7 ± 87.2 cc, with a VCR of -10.34 ± 7.58% (p<0.01). As TVs decreased, ΔD increased and DTI decreased. After the fourth week of radiotherapy (40 Gy), centroids of GTV, CTV1, and prophylactic CTV (CTV2) showed average deviations in ΔD of 7.6 ± 4.0, 6.9 ± 3.4, and 6.0 ± 3.0 mm, respectively. The average DTI of the heart decreased by 4.53 mm (from 15.61 ± 2.96 cm to 15.16 ± 2.27 cm). CONCLUSION: During radiotherapy for esophageal cancer, Targets and OARs change significantly in volume and position during the 2nd-4th weeks. Image-guidance and evaluation of dosimetric changes are recommended for these fractions of treatment to appropriate adjust treatment plans.

Emulsifying Properties of an Homologous Series of Medium- and Long-Chain d-Maltotriose Esters and their Impacts on the Viabilities of Selected Cell Lines.

The development of functional as well as nutritional surfactants for the food industry remains a matter of great interest. In the present study, a series of 6″-O-acylmaltotriose monoesters bearing alkyl side chains of 10-18 carbons was prepared by enzymatic means. The emulsions derived from those monoesters incorporating palmitoyl, stearoyl, and oleoyl side chains generally displayed advantageous shelf-lives, superior resistance to environmental variations, and more favorable droplet size distributions as well as stronger cytotoxic effects against various cancer cell lines. Ester 6 was shown to significantly inhibit the proliferation of MCF-7 breast cancer cells by inducing G1 phase arrest. Specifically, the levels of the G1 phase-related markers cyclin D1 and cyclin E as well as the cycle-dependent kinase 4 were suppressed by this particular ester. This study thus reveals that maltotriose esters can not only serve as novel functional food emulsifiers but also act, in vitro, as notable cytotoxic agents through a well-defined mechanism-of-action.

[Preparation of monoclonal antibody against Pfs25 protein and establishment of double antibody sandwich ELISA method].

AIM: To prepare the monoclonal antibody (mAb)against Pfs25 protein of Plasmodium falciparum, and establish the method of sandwich ELISA for detecting the Pfs25 protein. METHODS: Pfs25 protein the recombinant expressed by Pichia pastoris was purified. The purified Pfs25 protein as the antigen was used to immune the BALB/c mice, The secreting specific mAb positive cell strains, which were prepared by hybridizing the Sp2/0 myeloma cell and the spleen cell from immunized mice, were detected by indirect ELISA method. The ascites of mAb were collected from immunization F1 mice, and their biological properties were identified by indirect ELISA. The anti-Pfs25 antibody was labeled by Horseradish Peroxidase (HRP), the sandwich ELISA method to detect Pfs25 protein was established based on the anti-Pfs25 mAb 4B7 and 1B4 as coating and enzyme antibody, respectively. RESULTS: Three hybridoma cell lines secreting mAb against Pfs25 protein have been selected from the antibody positive hybridizing cells. The two of them have a better stability and specificity. The sandwich ELISA method detecting Pfs25 protein was established. Its detecte range was 0.07-1 mg/mL , and its sensitivity was 41.6 ng/mL. CONCLUSION: The anti-Pfs25 mAb are successfully prepared and the double antibody sandwich ELISA method detecting Pfs25 protein is established. Our study lay a foundation of developing transmission-blocking malaria vaccine with Pfs25 protein as antigen.