Comparative analysis of two dose-volume histogram prediction tools for treatment planning in volumetric-modulated arc therapy: A multi-planner study.

The increase in high-precision radiation therapy, particularly volumetric-modulated arc therapy (VMAT), has increased patient numbers and expanded treatment sites. However, a significant challenge in VMAT treatment planning is the inconsistent plan quality among different planners and facilities. This study explored the use of dose-volume histogram (DVH) prediction tools to address these disparities, specifically focusing on RapidPlan (Varian Medical Systems) and PlanIQ (Sun Nuclear). RapidPlan predicts achievable DVHs and automatically generates optimization objectives. While it has demonstrated organ-at-risk (OAR) dose reduction benefits, the quality of the plan used to build its model significantly affects its predictions. On the other hand, PlanIQ offers ease of use and does not require prior model-building. Five planners participated in this study, each creating two treatment plans: one referencing RapidPlan and the other using PlanIQ. The planners had the freedom to adjust parameters while referencing the DVH predictions. The plans were evaluated using "Plan Quality Metric" (PQM) scores to assess the planning target volume excluding the rectum and OARs. The results revealed that RapidPlan-referenced plans often outperformed PlanIQ-based plans, with less interplanner variability. PlanIQ played a pivotal role in the construction of the RapidPlan model. This study is the first to compare plans generated by multiple planners using both tools. This study provides insights into optimizing treatment planning by considering the characteristics of both RapidPlan and PlanIQ.

Comparing interplay effects in scanned proton therapy of lung cancer: Free breathing with various layer and volume rescanning versus respiratory gating with different gate widths.

PURPOSE: We investigated interplay effects and treatment time (TT) in scanned proton therapy for lung cancer patients. We compared free-breathing (FB) approaches with multiple rescanning strategies and respiratory-gating (RG) methods with various gating widths to identify the superior irradiation technique. METHODS: Plans were created with 4/1, 2/2, and 1/4 layered/volume rescans of FB (L4V1, L2V2, and L1V4), and 50%, 30%, and 10% gating widths of the total respiratory curves (G50, G30, and G10) of the RG plans with L4V1. We calculated 4-dimensional dynamic doses assuming a constant sinusoidal curve for six irradiation methods. The reconstructed doses per fraction were compared with planned doses in terms of dose differences in 99% clinical-target-volume (CTV) (ΔD99%), near-maximum dose differences (ΔD2%) at organs-at-risk (OARs), and TT. RESULTS: The mean/minimum CTV ΔD99% values for FB were -1.0%/-4.9%, -0.8%/-4.3%, and -0.1%/-1.0% for L4V1, L2V2, and L1V4, respectively. Those for RG were -0.3%/-1.7%, -0.1%/-1.0%, and 0.0%/-0.5% for G50, G30, and G10, respectively. The CTV ΔD99% of the RGs with less than 50% gate width and the FBs of L1V4 were within the desired tolerance (±3.0%), and the OARs ΔD2% for RG were lower than those for FB. The mean TTs were 90, 326, 824, 158, 203, and 422 s for L4V1, L2V2, L1V4, G50, G30, and G10, respectively. CONCLUSIONS: FB (L4V1) is the most efficient treatment, but not necessarily the optimal choice due to interplay effects. To satisfy both TT extensions and interplay, RG with a gate width as large as possible within safety limits is desirable.

Dose-volume comparisons of proton therapy for pencil beam scanning with and without multi-leaf collimator and passive scattering in patients with lung cancer.

This study evaluated the dose distributions of proton pencil beam scanning (PBS) with/without a multileaf collimator (MLC) compared to passive scattering (PS) for stage I/II lung cancers. Collimated/uncollimated (PBS+/PBS-) and PS plans were created for 20 patients. Internal-clinical-target-volumes (ICTVs) and planning-target-volumes (PTVs) with a 5 mm margin were defined on the gated CTs. Organs-at-risk (OARs) are defined as the normal lungs, spinal cord, esophagus, and heart. The prescribed dose was 66 Gy relative-biological-effectiveness (RBE) in 10 fractions at the isocenter and 50% volume of the ICTVs for the PS and PBS, respectively. We compared the target and OAR dose statistics from the dose volume histograms. The PBS+ group had a significantly better mean PTV conformity index than the PBS- and PS groups. The mean dose sparing for PBS+ was better than those for PBS- and PS. Only the normal lung doses of PBS- were worse than those of PS. The overall performance of the OAR sparing was in the order of PBS+, PBS-, and PS. The PBS+ plan showed significantly better target homogeneity and OAR sparing than the PBS- and PS plans. PBS requires collimating systems to treat lung cancers with the most OAR sparing while maintaining the target coverage.

Experimental validation of a 4D dynamic dose calculation model for proton pencil beam scanning without spot time stamp considering free-breathing motion.

PURPOSE: We developed a 4-dimensional dynamic dose (4DDD) calculation model for proton pencil beam scanning (PBS). This model incorporates the spill start time for all energies and uses the remaining irradiated spot time model instead of irradiated spot time logs. This study aimed to validate the calculation accuracy of a log file-based 4DDD model by comparing it with dose measurements performed under free-breathing conditions, thereby serving as an alternative approach to the conventional log file-based system. METHODS: Three cubic verification plans were created using a heterogeneous block phantom; these plans were created using 10 phase 4D-CT datasets of the phantom. The CIRS dynamic platform was used to simulate motion with amplitudes of 2.5, 3.75, and 5.0 mm. These plans consisted of eight- and two-layered rescanning techniques. The lateral profiles were measured using a 2D ionization chamber array (2D-array) and EBT3 Gafchromic films at four starting phases, including three sinusoidal curves (periods of 3, 4, and 6 s) and a representative patient curve during actual treatment. 4DDDs were calculated using in-house scripting that assigned a time stamp to each spot and performed dose accumulation using deformable image registration. Furthermore, to evaluate the impact of parameter selection on our 4DDD model calculations, simulations were performed assuming a ±10% change in irradiation time stamp (0.8 ± 0.08 s) and spot scan speed. We evaluated the 2D gamma index and the absolute point doses between the calculated values and the measurements. RESULTS: The 2D-array measurements revealed that the gamma scores for the static plans (no motion) and 4DDD plans exceeded 97.5% and 93.9% at 3%/3 mm, respectively. The average gamma score of the 4DDD plans was at least 96.1%. When using EBT3 films, the gamma scores of the 4DDD model exceeded 92.4% and 98.7% at 2%/2 mm and 3%/3 mm, respectively. Regarding the 4DDD point dose differences, more than 95% of the dose regions exhibited discrepancies within ±5.0% for 97.7% of the total points across all plans. The spot time assignment accuracy of our 4DDD model was acceptable even with ±10% sensitivity. However, the accuracy of the scan speed, when varied within ±10% sensitivity, was not acceptable (minimum gamma scores of 82.6% and maximum dose difference of 12.9%). CONCLUSIONS: Our 4DDD calculations under free-breathing conditions using amplitudes of less than 5.0 mm were in good agreement with the measurements regardless of the starting phases, breathing curve patterns (between 3 and 6 s periods), and varying numbers of layered rescanning. The proposed system allows us to evaluate actual irradiated doses in various breathing periods, amplitudes, and starting phases, even on PBS machines without the ability to record spot logs.

2'-Fucosyllactose Alleviates Early Weaning-Induced Anxiety-Like Behavior, Amygdala Hyperactivity, and Gut Microbiota Changes.

Early life stress has a significant impact on development of the central nervous system (CNS), with lasting rather than transient consequences; therefore, it is important to alleviate these effects. In recent years, functional communication between the CNS and gut microbiota through the so-called brain-gut-microbiota axis has been examined, and it is likely that prebiotics contribute to development of the CNS through the gut microbiota. In this study, we performed behavioral, neurohistological, and fecal microbiota analyses in early-weaned mice to examine the effects of 2'-fucosyllactose (2'-FL), a human milk oligosaccharide, on anxiety induced by early life stress. Mice weaned at 17 d old (17-d mice) showed anxiety-like behaviors, such as decreased time in the open arms in the elevated plus maze test, compared to mice weaned at 24 d old (24-d mice). The number of cells that were positive for the neuronal activity marker c-Fos in the amygdala was also higher in 17-d mice. The behavioral and neural abnormalities caused by early weaning were alleviated by post-weaning ingestion of 2'-FL. The composition of the fecal microbiota differed among control diet-fed 24-d and 17-d mice, and 2'-FL diet-fed 17-d mice. These findings indicate that human milk oligosaccharides 2'-FL alleviate early stress-induced anxiety, amygdala hyperactivity, and gut microbiota changes.

Dosimetric comparison of pencil beam scanning proton therapy with or without multi-leaf collimator versus volumetric-modulated arc therapy for treatment of malignant glioma.

This study aimed to examine the dosimetric effect of intensity-modulated proton therapy (IMPT) with a multi-leaf collimator (MLC) in treating malignant glioma. We compared the dose distribution of IMPT with or without MLC (IMPTMLC+ or IMPTMLC-, respectively) using pencil beam scanning and volumetric-modulated arc therapy (VMAT) in simultaneous integrated boost (SIB) plans for 16 patients with malignant gliomas. High- and low-risk target volumes were assessed using D2%, V90%, V95%, homogeneity index (HI), and conformity index (CI). Organs at risk (OARs) were evaluated using the average dose (Dmean) and D2%. Furthermore, the dose to the normal brain was evaluated using from V5Gy to V40Gy at 5 Gy intervals. There were no significant differences among all techniques regarding V90%, V95%, and CI for the targets. HI and D2% for IMPTMLC+ and IMPTMLC- were significantly superior to those for VMAT (p < 0.01). The Dmean and D2% of all OARs for IMPTMLC+ were equivalent or superior to those of other techniques. Regarding the normal brain, there was no significant difference in V40Gy among all techniques whereas V5Gy to V35Gy in IMPTMLC+ were significantly smaller than those in IMPTMLC- (with differences ranging from 0.45% to 4.80%, p < 0.05) and VMAT (with differences ranging from 6.85% to 57.94%, p < 0.01). IMPTMLC+ could reduce the dose to OARs, while maintaining target coverage compared to IMPTMLC- and VMAT in treating malignant glioma.

Validation of pencil beam scanning proton therapy with multi-leaf collimator calculated by a commercial Monte Carlo dose engine.

This study aimed to evaluate the clinical beam commissioning results and lateral penumbra characteristics of our new pencil beam scanning (PBS) proton therapy using a multi-leaf collimator (MLC) calculated by use of a commercial Monte Carlo dose engine. Eighteen collimated uniform dose plans for cubic targets were optimized by the RayStation 9A treatment planning system (TPS), varying scan area, modulation widths, measurement depths, and collimator angles. To test the patient-specific measurements, we also created and verified five clinically realistic PBS plans with the MLC, such as the liver, prostate, base-of-skull, C-shape, and head-and-neck. The verification measurements consist of the depth dose (DD), lateral profile (LP), and absolute dose (AD). We compared the LPs and ADs between the calculation and measurements. For the cubic plans, the gamma index pass rates (γ-passing) were on average 96.5% ± 4.0% at 3%/3 mm for the DD and 95.2% ± 7.6% at 2%/2 mm for the LP. In several LP measurements less than 75 mm depths, the γ-passing deteriorated (increased the measured doses) by less than 90% with the scattering such as the MLC edge and range shifter. The deteriorated γ-passing was satisfied by more than 90% at 2%/2 mm using uncollimated beams instead of collimated beams except for three planes. The AD differences and the lateral penumbra width (80%-20% distance) were within ±1.9% and ± 1.1 mm, respectively. For the clinical plan measurements, the γ-passing of LP at 2%/2 mm and the AD differences were 97.7% ± 4.2% on average and within ±1.8%, respectively. The measurements were in good agreement with the calculations of both the cubic and clinical plans inserted in the MLC except for LPs less than 75 mm regions of some cubic and clinical plans. The calculation errors in collimated beams can be mitigated by substituting uncollimated beams.

Absorption Kinetics of Ethanolamine Plasmalogen and Its Hydrolysate in Mice.

Ethanolamine plasmalogen (PlsEtn), a subclass of ethanolamine glycerophospholipid (EtnGpl), has been reported to have many biological and dietary functions. In terms of PlsEtn absorption, some studies have reported that PlsEtn is re-esterized at the sn-2 position using lymph cannulation and the everted jejunal sac model. In this study, we aimed to better understand the uptake kinetics of PlsEtn and increase its absorption. We thus compared the uptake kinetics of PlsEtn with that of the lyso-form, in which the fatty acid at the sn-2 position was hydrolyzed enzymatically. Upon administration of EtnGpl (extracted from oysters or ascidians, 75.4 mol% and 88.4 mol% of PlsEtn ratio, respectively), the plasma PlsEtn species in mice showed the highest levels at 4 or 8 hours after administration. In the contrast, administration of the EtnGpl hydrolysate, which contained lysoEtnGpl and free fatty acids, markedly increased the plasma levels of PlsEtn species at 2 h after administration. The area under the plasma concentration-time curve (AUC), especially the AUC0-4 h of PlsEtn species, was higher with hydrolysate administration than that with EtnGpl administration. These results indicate that EtnGpl hydrolysis accelerated the absorption and metabolism of PlsEtn. Consequently, using a different experimental approach from that used in previous studies, we reconfirmed that PlsEtn species were absorbed via hydrolysis at the sn-2 position, suggesting that hydrolysis in advance could increase PlsEtn uptake.

Dietary PlsEtn Ameliorates Colon Mucosa Inflammatory Stress and ACF in DMH-Induced Colon Carcinogenesis Mice: Protective Role of Vinyl Ether Linkage.

Ethanolamine plasmalogen (PlsEtn), a sub-class of ethanolamine glycerophospholipids (EtnGpl), is a universal phospholipid in mammalian membranes. Several researchers are interested in the relationship between colon carcinogenesis and colon PlsEtn levels. Here, we evaluated the functional role of dietary purified EtnGpl from the ascidian muscle (87.3 mol% PlsEtn in EtnGpl) and porcine liver (7.2 mol% PlsEtn in EtnGpl) in 1,2-dimethylhydrazine (DMH)-induced aberrant crypt foci (ACF) in vivo, and elucidated the possible underlying mechanisms behind it. Dietary EtnGpl-suppressed DMH-induced aberrant crypt with one foci (AC1) and total ACF formation (P < 0.05). ACF suppression by dietary ascidian muscle EtnGpl was higher compared with dietary porcine liver EtnGpl. Additionally, dietary EtnGpl decreased DMH-induced oxidative damage, overproduction of TNF-α, and expression of apoptosis-related proteins in the colon mucosa. The effect of dietary ascidian muscle EtnGpl showed superiority compared with dietary porcine liver EtnGpl. Our results demonstrate the mechanisms by which dietary PlsEtn suppress ACF formation and apoptosis. Dietary PlsEtn attained this suppression by reducing colon inflammation and oxidative stress hence a reduction in DMH-induced intestinal impairment. These findings provide new insights about the functional role of dietary PlsEtn during colon carcinogenesis.

Improved design of peptides exhibiting angiogenic activities for clinical applications.

Vascularization is one of the key steps for engraftment in regenerative medicine. Previously one of the authors had discovered peptides exhibiting significant angiogenic activities designated AGP and elucidated the active core. For neovascularization basic fibroblast growth factor is used although permeation can be envisaged. The original AGPs did not suffer from this although their half-life times are short because of decomposition by endogenous enzymes. Several new AGP-libraries have been constructed and their enzymatic resistance has been investigated by the use of human umbilical vein endothelial cells to find candidates for clinical applications.

Drosera tokaiensis extract containing multiple phenolic compounds inhibits the formation of advanced glycation end-products.

The accumulation of advanced glycation end-products (AGEs) correlates with aging and accompanies the onset of age-related diseases, such as diabetes and arteriosclerosis. Therefore, a daily intake of natural compounds that inhibit the production of AGEs may be beneficial in preventing these diseases. In this study, we evaluated the inhibitory effects of 14 natural crude extracts, including those of Drosera species, which possess anti-inflammatory activity, on the formation of AGEs, such as Nω-(carboxymethyl)arginine (CMA) and Nε-(carboxymethyl)lysine (CML). Crude extracts of Drosera inhibited the formation of CMA and CML by incubation on gelatin with ribose more effectively than with other extracts, so active compounds that prevent AGE formation were purified from Drosera tokaiensis, which is endemic to Japan. Several compounds were purified from D. tokaiensis extracts using HPLC and identified by NMR analysis. These compounds included ellagic acid, 3,3'-di-O-methylellagic acid 4'-glucoside, myricitrine, and quercimelin. Furthermore, all compounds showed a significantly higher inhibitory effect on CMA and CML formations than aminoguanidine. Specifically, ellagic acid and myricitrine had the highest inhibitory effects of the compounds tested. However, not all compounds showed inhibition of CMA formation in a mixture of gelatin and glyoxal (GO). These results suggest that the compounds in D. tokaiensis inhibit CMA and CML formations via the antioxidative activity of phenolic compounds, rather than GO trapping action. This study provides the first evidence that D. tokaiensis inhibits CMA and CML formations and that phenolic compounds such as ellagic acid and myricitrine play an important role as active components of D. tokaiensis extracts.

Dose distribution of intensity-modulated proton therapy with and without a multi-leaf collimator for the treatment of maxillary sinus cancer: a comparative effectiveness study.

BACKGROUND: Severe complications, such as eye damage and dysfunciton of salivary glands, have been reported after radiotherapy among patients with head and neck cancer. Complications such as visual impairment have also been reported after proton therapy with pencil beam scanning (PBS). In the case of PBS, collimation can sharpen the penumbra towards surrounding normal tissue in the low energy region of the proton beam. In the current study, we examined how much the dose to the normal tissue was reduced by when intensity-modulated proton therapy (IMPT) was performed using a multi-leaf collimator (MLC) for patients with maxillary sinus cancer. METHODS: Computed tomography findings of 26 consecutive patients who received photon therapy at Okayama University Hospital were used in this study. We compared D2% of the region of interest (ROI; ROI-D2%) and the mean dose of ROI (ROI-mean) with and without the use of an MLC. The organs at risk (OARs) were the posterior retina, lacrimal gland, eyeball, and parotid gland. IMPT was performed for all patients. The spot size was approximately 5-6 mm at the isocenter. The collimator margin was calculated by enlarging the maximum outline of the target from the beam's eye view and setting the margin to 6 mm. All plans were optimized with the same parameters. RESULTS: The mean of ROI-D2% for the ipsilateral optic nerve was significantly reduced by 0.48 Gy, and the mean of ROI-mean for the ipsilateral optic nerve was significantly reduced by 1.04 Gy. The mean of ROI-mean to the optic chiasm was significantly reduced by 0.70 Gy. The dose to most OARs and the planning at risk volumes were also reduced. CONCLUSIONS: Compared with the plan involving IMPT without an MLC, in the dose plan involving IMPT using an MLC for maxillary sinus cancer, the dose to the optic nerve and optic chiasm were significantly reduced, as measured by the ROI-D2% and the ROI-mean. These findings demonstrate that the use of an MLC during IMPT for maxillary sinus cancer may be useful for preserving vision and preventing complications.

Glucoselysine is derived from fructose and accumulates in the eye lens of diabetic rats.

Prolonged hyperglycemia generates advanced glycation end-products (AGEs), which are believed to be involved in the pathogenesis of diabetic complications. In the present study, we developed a polyclonal antibody against fructose-modified proteins (Fru-P antibody) and identified its epitope as glucoselysine (GL) by NMR and LC-electrospray ionization (ESI)- quadrupole TOF (QTOF) analyses and evaluated its potential role in diabetes sequelae. Although the molecular weight of GL was identical to that of fructoselysine (FL), GL was distinguishable from FL because GL was resistant to acid hydrolysis, which converted all of the FLs to furosine. We also detected GL in vitro when reduced BSA was incubated with fructose for 1 day. However, when we incubated reduced BSA with glucose, galactose, or mannose for 14 days, we did not detect GL, suggesting that GL is dominantly generated from fructose. LC-ESI-MS/MS experiments with synthesized [13C6]GL indicated that the GL levels in the rat eye lens time-dependently increase after streptozotocin-induced diabetes. We observed a 31.3-fold increase in GL 8 weeks after the induction compared with nondiabetic rats, and Nϵ-(carboxymethyl)lysine and furosine increased by 1.7- and 21.5-fold, respectively, under the same condition. In contrast, sorbitol in the lens levelled off at 2 weeks after diabetes induction. We conclude that GL may be a useful biological marker to monitor and elucidate the mechanism of protein degeneration during progression of diabetes.

Photo-Modification of Melanin by a Mid-infrared Free-electron Laser.

Melanin is rigidly constructed by several nitrogen-containing aromatic rings, and its excess accumulation in skin tissue is closely associated with melanosis. Although visible lasers (wavelength: 600-1000 nm) are conventionally used for the photo-thermolysis of melanocyte, several pigmented nevi are difficult to be treated. Here, we propose an alternate method for targeting the molecular structure of melanin using an infrared free-electron laser (FEL) tuned to 5.8 µm that corresponds to the stretching vibrational mode of carboxylate group. A drastic morphological change on the black-colored surface of melanin powder was observed after the pulse irradiation with power energy of 500 mJ cm-2 , and the minimum irradiation time for damage to the morphology was 1.4 s. Analyses by mass spectroscopy, infrared spectroscopy, and 13 C-nuclear magnetic resonance implied that a pyrrole group was removed by the FEL irradiation. In addition, the FEL irradiation dispersed almost all of the melanoma cells from a culture solution without any influence on other ingredients in the medium, and one-cell analysis by infrared microscopy showed that the structure of melanoma could be substantially damaged by the irradiation. This study proposes the potency of intense mid-infrared laser as novel alternative way to reduce melanin.

Applications of a novel biodetection system to saliva using protein fingerprints with data processing.

A fundamental method has been developed focusing on a facile and rapid examination of periodontal disease. Periodontal disease is an oral disease thought to affect 80% of adults, and early detection with treatment is desirable for the improvement of the quality of life. Unfortunately conventional methods are not consistent as the disease is caused by a number of undefined bacteria and detection relies on the skills of the dentist. Thus an objective detection system is required. We have performed an experiment on saliva using a novel biodetection system, designated PepTenChip®. A disease model for saliva was prepared using a specimen from a healthy subject and a mixture of hemoglobin (f-Hb) and lactate dehydrogenase (LDH), which is used as a periodontal disease marker protein with healthy saliva. PepTenChip® is a peptide microarray in which fluorescent labelled structured peptides are immobilized on a novel amorphous carbon substrate. Since the peptides used as capture molecules are fluorescently labelled, labeling of analytes is not necessary. The fluorescence intensity change before and after application of analytes are detected rather than the ON/OFF detection common to conventional microarrays using a set of antigen-antibody. The fluorescence intensity value changes according to the concentration of captured protein allowing the generation of protein fingerprint (PFP) and dendrograms. The present method does not rely on a "one to one" interaction, unlike conventional biodetection, and advantages can be envisaged in the case of an undefined or unknown cause of disease. The statistical analyses, such as multivariate analyses, allow classification of the type of proteins added in saliva as mimetics of disease. PepTenChip® system is useful and convenient for examination of periodontal disease in health care.

High throughput sequencing of cyclic peptide immobilized on a gel-type single bead.

Relatively larger scale peptide libraries immobilized on a gel-type solid support consisting of 24 natural and non-natural amino acids by the "split and combine method" have been constructed to find interacting molecules. The diversity was ca. 200 millions of hexapeptides with cysteinyl residues forming cyclotide. Selected beads after screening can be sequenced by the conventional Edman degradation, although several restrictions and the problems are known. To resolve these, a novel combinatorial method involving partial acid hydrolysis followed by liquid chromatography with on-line mass spectrometric analyses has been established. Problems were uncovered in an early stage of the process. Uncertain assignment caused by byproducts derived from a cystine residue and other materials could be resolved by optimal hydrolysis conditions and derivatization before mass spectrometric analysis. Discrimination between Leu and Ile could be performed using high energy collision induced dissociation in the high resolution MALDI-TOF-MS/MS. The present optimized protocol is useful for discovery of sequences of interacting molecules and a second library construction.

Recognition of a monoclonal antibody against a small molecular weight antigen by monitoring the antigen-antibody reaction using fluorescence labeled structured peptides.

Interaction between proteins (as analytes) and de novo designed structured peptides as capture molecules cause structural changes, which are reflected in fluorescent-intensity changes of labeled peptides in a dose dependent manner. In contrast to conventional detection methods our detection system does not involve the detection of specific molecules themselves in a 1:1 manner, but uses the principle of the differences in fluorescent intensity changes of capture peptides upon addition of analytes. Instead of the use of secondary antibodies we have attempted monitoring these structural changes by an array of de novo designed synthetic and structured peptides. In the present study we have focused on a recognition system, 5-fluorouracil, as a low molecular antigen and a monoclonal antibody against 5-FU. The fluorescent intensity changes of fluorescent labeled peptides have been measured after incubation with a monoclonal antibody and again after further incubation with the antigen, 5-FU. Unique intensity changes were found for several peptides in the fluorescent peptide library that allowed the visualization as a color-coded protein fingerprint. The peptide screen used in the present study offers a useful detection system as capture molecules for peptide-based microarrays.

Efficient drug delivery of Paclitaxel glycoside: a novel solubility gradient encapsulation into liposomes coupled with immunoliposomes preparation.

Although the encapsulation of paclitaxel into liposomes has been extensively studied, its significant hydrophobic and uncharged character has generated substantial difficulties concerning its efficient encapsulation into the inner water core of liposomes. We found that a more hydrophilic paclitaxel molecule, 7-glucosyloxyacetylpaclitaxel, retained tubulin polymerization stabilization activity. The hydrophilic nature of 7-glucosyloxyacetylpaclitaxel allowed its efficient encapsulation into the inner water core of liposomes, which was successfully accomplished using a remote loading method with a solubility gradient between 40% ethylene glycol and Cremophor EL/ethanol in PBS. Trastuzumab was then conjugated onto the surface of liposomes as immunoliposomes to selectively target human epidermal growth factor receptor-2 (HER2)-overexpressing cancer cells. In vitro cytotoxicity assays revealed that the immunoliposomes enhanced the toxicity of 7-glucosyloxyacetylpaclitaxel in HER2-overexpressing cancer cells and showed more rapid suppression of cell growth. The immunoliposomes strongly inhibited the tumor growth of HT-29 cells xenografted in nude mice. Notably, mice survived when treated with the immunoliposomes formulation, even when administered at a lethal dose of 7-glucosyloxyacetylpaclitaxel in vivo. This data successfully demonstrates immunoliposomes as a promising candidate for the efficient delivery of paclitaxel glycoside.