PSMA-reactive NB7 single domain antibody fragment: A potential scaffold for developing prostate cancer theranostics.

INTRODUCTION: Single domain antibody fragments (sdAbs) are an appealing scaffold for radiopharmaceutical development due to their small size (~15 kDa), high solubility, high stability, and excellent tumor penetration. Previously, we developed NB7 sdAb, which has very high affinity for an epitope on PSMA that is different from those targeted by small molecule PSMA inhibitors. Herein, we evaluated NB7 after radioiodination using [*I]SGMIB (1,3,4-isomer) and iso-[*I]SGMIB (1,3,5-isomer), as well as their 211At-labeled analogues. METHODS: [*I]SGMIB, iso-[*I]SGMIB, [211At]SAGMB, and iso-[211At]SAGMB conjugates of NB7 sdAb were synthesized and their binding affinity, cell uptake and internalization were assessed in PSMA+ PC3 PIP and PSMA- PC3 flu cells. Biodistribution studies were performed in mice bearing PSMA+ PC3 PIP xenografts. First, a single-label experiment evaluated the tissue distribution of a NB7 bearing a His6-tag (NB7H6) and labeled with iso-[125I]SGMIB. Three paired-label experiments then were performed to compare: a) NB7 labeled using [*I]SGMIB and iso-[*I]SGMIB, b) 131I- vs 211At-labeled NB7 conjugates and c) [125I]SGMIB-NB7H6 to the small molecule PSMA inhibitor [131I]YF2. RESULTS: All NB7 radioconjugates bound specifically to PSMA with dissociation constants, Kd, in the low nM range (1.4-6.4 nM). An initial biodistribution study demonstrated good tumor uptake for iso-[125I]SGMIB-NB7H6 (7.2 ± 1.5 % ID/g at 1 h) and no deleterious effect of the His6-tag on renal activity levels, which declined to 3.1 ± 1.1 % ID/g by 4 h. Paired-label biodistribution found no distinction between the two SGMIB isomer NB7 conjugates with the [131I]SGMIB-NB7-to-iso-[125I]SGMIB-NB7 tumor uptake ratios not significantly different from unity: 1.06 ± 0.08 at 1 h, 1.04 ± 0.12 at 4 h, and 1.07 ± 0.09 at 24 h. Both isomer conjugates cleared rapidly from normal tissues and exhibited very low uptake in thyroid, lacrimal and salivary glands. Paired-label biodistribution of [131I]SGMIB-NB7H6 and [211At]SAGMB-NB7H6 demonstrated similar tumor uptake and kidney clearance for the two radioconjugates. However, levels of 211At in thyroid, stomach, salivary and lacrimal glands were significantly higher (P < 0.05) that those for 131I suggesting greater dehalogenation for [211At]SAGMB-NB7H6. Finally, co-administration of [125I]SGMIB-NB7H6 and [131I]YF2 demonstrated good tumor uptake for both with considerably more rapid renal clearance for the NB7 radioconjugate. CONCLUSION: NB7 radioconjugates exhibited good accumulation in PSMA-positive xenografts with rapid clearance from kidney and other normal tissues. We conclude that NB7 is a potentially useful scaffold for developing PSMA-targeted theranostics with different characteristics than current small molecule and antibody-based approaches.

Effective Treatment of Human Breast Carcinoma Xenografts with Single-Dose 211At-Labeled Anti-HER2 Single-Domain Antibody Fragment.

Single-domain antibody fragments (sdAbs) are attractive for targeted α-particle therapy, particularly with 211At, because of their rapid accumulation in tumor and clearance from normal tissues. Here, we evaluate the therapeutic potential of this strategy with 5F7 and VHH_1028-2 sdAbs that bind with high affinity to domain IV of human epidermal growth factor receptor type 2 (HER2). Methods: The HER2-specific sdAbs and HER2-irrelevant VHH_2001 were labeled using N-succinimidyl-3-211At-astato-5-guanidinomethyl benzoate (iso-211At-SAGMB). The cytotoxicity of iso- 211At-SAGMB-5F7 and iso- 211At-SAGMB-VHH_2001 were compared on HER2-expressing BT474 breast carcinoma cells. Three experiments in mice with subcutaneous BT474 xenografts were performed to evaluate the therapeutic effectiveness of single doses of iso- 211At-SAGMB-5F7 (0.7-3.0 MBq), iso- 211At-SAGMB-VHH_1028 (1.0-3.0 MBq), and iso- 211At-SAGMB-VHH_1028 and iso- 211At-SAGMB-VHH_2001 (∼1.0 MBq). Results: Clonogenic survival of BT474 cells was reduced after exposure to iso- 211At-SAGMB-5F7 (D0 = 1.313 kBq/mL) whereas iso- 211At-SAGMB-VHH_2001 was ineffective. Dose-dependent tumor growth inhibition was observed with 211At-labeled HER2-specific 5F7 and VHH_1028 but not with HER2-irrelevant VHH_2001. At the 3.0-MBq dose, complete tumor regression was seen in 3 of 4 mice treated with iso- 211At-SAGMB-5F7 and 8 of 11 mice treated with iso- 211At-SAGMB-VHH_1028; prolongation in median survival was 495% and 414%, respectively. Conclusion: Combining rapidly internalizing, high-affinity HER2-targeted sdAbs with the iso- 211At-SAGMB residualizing prosthetic agent is a promising strategy for targeted α-particle therapy of HER2-expressing cancers.

Critical role of PAFR/YAP1 positive feedback loop in cardiac fibrosis.

Aberrant activation of cardiac fibroblasts is the main cause and character of cardiac fibrosis, and inhibition of cardiac fibrosis becomes a promising treatment for cardiac diseases. Platelet-activating factor (PAF) and Hippo pathway is recently recognized as key signaling mechanisms in cardiovascular diseases. In this study we explored the potential roles of PAF and Hippo signaling pathway in cardiac fibrosis. Myocardial infarction (MI) was induced in mice by left anterior descending artery ligation. After 28 days, the mice were sacrificed, and the hearts were collected for analyses. We showed that PAF receptor (PAFR) and yes-associated protein 1 (YAP1, a key effector in the Hippo pathway) were significantly increased in the heart of MI mice. Increased expression of PAFR and YAP1 was also observed in angiotensin II (Ang II)-treated mouse cardiac fibroblasts. In mouse cardiac fibroblasts, forced expression of YAP1 increased cell viability, resulted in collagen deposition and promoted fibroblast-myofibroblast transition. We showed that PAF induced fibrogenesis through activation of YAP1 and promoted its nuclear translocation via interacting with PAFR, while YAP1 promoted the expression of PAFR by binding to and activating transcription factor TEAD1. More importantly, silencing PAFR or YAP1 by shRNA, or using transgenic mice to induce the conditional deletion of YAP1 in cardiac fibroblasts, impeded cardiac fibrosis and improved cardiac function in MI mice. Taken together, this study elucidates the role and mechanisms of PAFR/YAP1 positive feedback loop in cardiac fibrosis, suggesting a potential role of this pathway as novel therapeutic targets in cardiac fibrosis.

Evaluation of an 131I-labeled HER2-specific single domain antibody fragment for the radiopharmaceutical therapy of HER2-expressing cancers.

Radiopharmaceutical therapy (RPT) is an attractive strategy for treatment of disseminated cancers including those overexpressing the HER2 receptor including breast, ovarian and gastroesophageal carcinomas. Single-domain antibody fragments (sdAbs) exemplified by the HER2-targeted VHH_1028 evaluated herein are attractive for RPT because they rapidly accumulate in tumor and clear faster from normal tissues than intact antibodies. In this study, VHH_1028 was labeled using the residualizing prosthetic agent N-succinimidyl 3-guanidinomethyl 5-[131I]iodobenzoate (iso-[131I]SGMIB) and its tissue distribution evaluated in the HER2-expressing SKOV-3 ovarian and BT474 breast carcinoma xenograft models. In head-to-head comparisons to [131I]SGMIB-2Rs15d, a HER2-targeted radiopharmaceutical currently under clinical investigation, iso-[131I]SGMIB-VHH_1028 exhibited significantly higher tumor uptake and significantly lower kidney accumulation. The results demonstrated 2.9 and 6.3 times more favorable tumor-to-kidney radiation dose ratios in the SKOV-3 and BT474 xenograft models, respectively. Iso-[131I]SGMIB-VHH_1028 was prepared using a solid-phase extraction method for purification of the prosthetic agent intermediate Boc2-iso-[131I]SGMIB that reproducibly scaled to therapeutic-level doses and obviated the need for its HPLC purification. Single-dose (SKOV-3) and multiple-dose (BT474) treatment regimens demonstrated that iso-[131I]SGMIB-VHH_1028 was well tolerated and provided significant tumor growth delay and survival prolongation. This study suggests that iso-[131I]SGMIB-VHH_1028 is a promising candidate for RPT of HER2-expressing cancers and further development is warranted.

Gold Nanostars: A Novel Platform for Developing 211At-Labeled Agents for Targeted Alpha-Particle Therapy.

AIM: To develop an innovative 211At nanoplatform with high radiolabeling efficiency and low in vivo deastatination for future targeted alpha-particle therapy (TAT) to treat cancer. METHODS: Star-shaped gold nanoparticles, gold nanostars (GNS), were used as the platform for 211At radiolabeling. Radiolabeling efficiency under different reaction conditions was tested. Uptake in the thyroid and stomach after systemic administration was used to evaluate the in vivo stability of 211At-labeled GNS. A subcutaneous U87MG human glioma xenograft murine model was used to preliminarily evaluate the therapeutic efficacy of 211At-labeled GNS after intratumoral administration. RESULTS: The efficiency of labeling GNS with 211At was almost 100% using a simple and rapid synthesis process that was completed in only 1 min. In vitro stability test in serum showed that more than 99% of the 211At activity remained on the GNS after 24 h incubation at 37°C. In vivo biodistribution results showed low uptake in the thyroid (0.44-0.64%ID) and stomach (0.21-0.49%ID) between 0.5 and 21 h after intravenous injection, thus indicating excellent in vivo stability of 211At-labeled GNS. The preliminary therapeutic efficacy study demonstrated that 211At labeled GNS substantially reduced tumor growth (P < 0.001; two-way ANOVA) after intratumoral administration. CONCLUSION: The new 211At radiolabeling strategy based on GNS has the advantages of a simple process, high labeling efficiency, and minimal in vivo dissociation, making it an attractive potential platform for developing TAT agents that warrants further evaluation in future preclinical studies directed to evaluating prospects for clinical translation.

Zinc provides neuroprotection by regulating NLRP3 inflammasome through autophagy and ubiquitination in a spinal contusion injury model.

AIM: Spinal cord injury (SCI) is a serious disabling injury worldwide, and the excessive inflammatory response it causes plays an important role in secondary injury. Regulating the inflammatory response can be a potential therapeutic strategy for improving the prognosis of SCI. Zinc has been demonstrated to have a neuroprotective effect in experimental spinal cord injury models. In this study, we aimed to explore the neuroprotective effect of zinc through the suppression of the NLRP3 inflammasome. METHOD: Allen's method was used to establish an SCI model in C57BL/6J mice. The Basso Mouse Scale (BMS), Nissl staining were employed to confirm the protective effect of zinc on neuronal survival and functional recovery in vivo. Western blotting (WB), immunofluorescence (IF), and enzyme-linked immunosorbent assay (ELISA) were used to detect the expression levels of NLRP3 inflammasome and autophagy-related proteins. Transmission electron microscopy (TEM) was used to confirm the occurrence of zinc-induced autophagy. In vitro, lipopolysaccharide (LPS) and ATP polarized BV2 cells to a proinflammatory phenotype. 3-Methyladenine (3-MA) and bafilomycin A1 (BafA1) were chosen to explore the relationship between the NLRP3 inflammasome and autophagy. A coimmunoprecipitation assay was used to detect the ubiquitination of the NLRP3 protein. RESULTS: Our data showed that zinc significantly promoted motor function recovery after SCI. In vivo, zinc treatment inhibited the protein expression level of NLRP3 while increasing the level of autophagy. These effects were fully validated by the polarization of BV2 cells to a proinflammatory phenotype. The results showed that when 3-MA and BafA1 were applied, the promotion of autophagy by zinc was blocked and that the inhibitory effect of zinc on NLRP3 was reversed. Furthermore, co-IP confirmed that the promotion of autophagy by zinc also activated the protein expression of ubiquitin and suppressed high levels of NLRP3. CONCLUSION: Zinc provides neuroprotection by regulating NLRP3 inflammasome through autophagy and ubiquitination after SCI.

Labeling Monoclonal Antibody with α-emitting 211At at High Activity Levels via a Tin Precursor.

Background: In a previous clinical study, the authors evaluated the potential of antitenascin C monoclonal antibody (mAb) 81C6 labeled with 211At via the prosthetic agent N-succinimidyl 3-[211At]astatobenzoate (SAB) for the treatment of primary brain tumors. Although encouraging results were obtained, labeling chemistry failed while attempting to escalate the dose to 370 MBq. The goal of the current study was to develop a revised procedure less susceptible to radiolysis-mediated effects on 211At labeling that would be suitable for use at higher activity levels of this α-emitter. Materials and Methods: Addition of N-chlorosuccinimide to the methanol used to remove the 211At from the cryotrap after bismuth target distillation was done to thwart radiolytic decomposition of reactive 211At and the tin precursor. A series of 11 reactions were performed to produce SAB at initial 211At activity levels of 0.31-2.74 GBq from 50 µg of N-succinimidyl 3-trimethylstannylbenzoate (Me-STB), which was then reacted with murine 81C6 mAb without purification of the SAB intermediate. Radiochemical purity, immunoreactive fraction, sterility, and apyrogenicity of the 211At-labeled 81C6 preparations were evaluated. Results: Murine 81C6 mAb was successfully labeled with 211At using these revised procedures with improved radiochemical yields and decreased overall synthesis time compared with the original clinical labeling procedure. Conclusions: With 2.74 GBq of 211At, it was possible to produce 1.0 GBq of 211At-labeled 81C6 with an immunoreactive fraction of 92%. These revised procedures permit production of 211At-labeled mAbs suitable for use at clinically relevant activity levels.

Comparative evaluation of the wound-healing potency of recombinant bFGF and ski gene therapy in rats.

We previously demonstrated that cellular Sloan-Kettering Institute (c-Ski) played a dual role, both promoting wound healing and alleviating scar formation. However, its mechanism and therapeutic effects are not clear, especially compared with widely used treatments, such as basic fibroblast growth factor (bFGF) administration. However, Ski treatment led to an even shorter healing time and a more significant reduction in scar area than bFGF treatment. The mechanism underlying this difference was related to a reduced inflammatory response, more rapid re-epithelialization, less collagen after healing and a greater reduction in the proportion of alpha-smooth muscle actin and SMemb-positive cells after Ski treatment. These results not only confirm that Ski plays a dual role in promoting healing and reducing scarring but also suggest that Ski yields better treatment effects than bFGF, indicating better potential therapeutic effects in wound repair.

Phospholipids fatty acids of drinking water reservoir sedimentary microbial community: Structure and function responses to hydrostatic pressure and other physico-chemical properties.

Microbial communities in three drinking water reservoirs, with different depth in Xi'an city, were quantified by phospholipids fatty acids analysis and multivariate statistical analysis was employed to interpret their response to different hydrostatic pressure and other physico-chemical properties of sediment and overlying water. Principle component analyses of sediment characteristics parameters showed that hydrostatic pressure was the most important effect factor to differentiate the overlying water quality from three drinking water reservoirs from each other. NH4+ content in overlying water was positive by related to hydrostatic pressure, while DO in water-sediment interface and sediment OC in sediment were negative by related with it. Three drinking water reservoir sediments were characterized by microbial communities dominated by common and facultative anaerobic Gram-positive bacteria, as well as, by sulfur oxidizing bacteria. Hydrostatic pressure and physico-chemical properties of sediments (such as sediment OC, sediment TN and sediment TP) were important effect factors to microbial community structure, especially hydrostatic pressure. It is also suggested that high hydrostatic pressure and low dissolved oxygen concentration stimulated Gram-positive and sulfate-reducing bacteria (SRB) bacterial population in drinking water reservoir sediment. This research supplied a successful application of phospholipids fatty acids and multivariate analysis to investigate microbial community composition response to different environmental factors. Thus, few physico-chemical factors can be used to estimate composition microbial of community as reflected by phospholipids fatty acids, which is difficult to detect.

[Comparison of the therapeutic effect on skeletal fluorosis and impact on urine fluoride value among fire needle therapy, electroacupuncture and calcium carbonate D3].

OBJECTIVE: To observe the impacts on skeletal fluorosis pain, joint motor dysfunction and urine fluoride excretion in the treatment with fire needle therapy, electroacupuncture and calcium carbonate D3. METHODS: The randomized controlled trial was adopted. Ninety-five patients were randomized into a fire needle group (31 cases), an electroacupuncture group (33 cases) and a calcium carbonate D3 group (31 cases). In the fire needle group and the electroacupuncture group, Ashi points, Dazhui (GV 14), Geshu (BL 17), Quchi (LI 11), Hegu (LI 4), Xuehai (SP 10) points were selected and stimulated with fire needle and electroacupuncture separately, three times a week. In the calcium carbonate D3 group, calcium carbonate D3 tablets was prescribed for oral administration, 600 mg each time, twice a day. The duration of treatment was 2 months in the electroacupuncture group and calcium carbonate D3 group and 1 month in the fire needle group. VAS score, the range of motion (ROM) and urine fluoride value were compared before and after treatment in the patients of the three groups. RESULTS: After treatment, VAS value and ROM were improved significantly in the patients of the three groups (all P < 0.05), the difference was not significant in comparison of the three groups (all P > 0.05). After treatment, the urine fluoride value was increased significantly in the fire needle group [(7.89 +/- 3.61) mg/L vs (9.81 +/- 4.17) mg/L, P < 0.01] and was increased in the electroacupuncture group [(7.53 +/- 3.46) mg/L vs (8.97 +/- 4.21) mg/L, P < 0.05]. The difference was not significant in comparison before and after treatment in the calcium carbonate D3 group (P > 0.05). CONCLUSION: The fire needle therapy, electroacupuncture and calcium carbonate D3 all have the clinical value in the prevention and treatment of skeletal fluorosis and the difference in the therapeutic effect has not been discovered among them yet at present. But it has been found that the fire needle therapy and electroacupuncture display the active significance in the promotion of urine fluoride excretion.

Orthodontic decompensation and correction of skeletal Class III malocclusion with gradual dentoalveolar remodeling in a growing patient.

An 8-year-old girl with a skeletal Class III malocclusion was treated in 2 phases. Maxillary expansion and protraction were carried out as the early intervention. However, her maxillary hypoplasia and mandibular hyperplasia deteriorated with age. The phase 2 comprehensive treatment began with proper mechanics when she was 12 years old with growth potential. In the maxillary arch, an auxiliary rectangular wire was used with a round main wire and an opening spring to create space for the impacted teeth and to bodily move the anterior teeth forward. Decompensation of mandibular incisors and correction of the Class III malocclusion were achieved by short Class III elastics with light forces and a gentle interaction between the rectangular wires and the lingual root-torque slots. The phase 2 active treatment period was 4 years 8 months. The 2-year follow-up indicated that our treatment results were quite stable.

Preparation of N-doped TiO2 by oxidizing TiN and its application on phenol degradation.

Incomplete oxidation of titanium nitride (TiN) to prepare nitrogen-doped TiO2 was verified by calcining TiN at different temperatures in air for 30 min. The as-prepared samples were characterized by X-ray diffraction, UV-Vis diffuse reflectance spectra and X-ray photoelectron spectroscopy. The results confirmed that oxidizing TiN incompletely is an effective and simple method to prepare nitrogen-doped TiO2. Photocatalytic degradation of phenol was conducted to evaluate the photocatalytic activity of as-prepared samples. The results showed that phenol can be degraded efficiently by the as-prepared samples under visible light; low phenol concentration was conducive to degradation; the optimum calcination temperature and photocatalyst dosage are 650 °C and 0.5 g/L, respectively. The effects of different light sources on phenol degradation were compared. The reusability of nitrogen-doped TiO2 was tested and the results indicated a relatively good reusability under laboratory conditions.

Dual infection with Anaplasma phagocytophilum and Babesia microti in a Rattus norvegicus, China.

Anaplasma phagocytophilum and Babesia microti were isolated from a Rattus norvegicus in the middle east of China through propagation in experimental mice. Their molecular biological characteristics were described. The public health and veterinary significance of the dual infection of the 2 tick-borne agents deserve further investigation.

Comparison of Chinese and white Bolton standards at age 13.

OBJECTIVES: To create a combined male-female Chinese Bolton standard for age 13 and to compare it to the combined Bolton standard for white 13 year olds. MATERIALS AND METHODS: Thirty-two Chinese and 32 white subjects (16 adolescent boys and 16 adolescent girls aged 13 years in each ethnic group) who fulfilled the selection criteria used to create the original Bolton standards were enrolled. Their cephalograms were traced and then averaged two at a time following the Bolton method. In addition to creating the template from the 32 subjects in each group, 43 linear and angular variables were measured and compared between the two ethnic groups and between the two sexes in each ethnic group using independent t-tests. A P value of .05 was used to assign statistical significance. The male-female combined templates for 13 year olds were also compared superimposing either in the Bolton relation or by soft tissue. RESULTS: No sexual dimorphism was found in the white subjects, whereas the Chinese girls had decreased upper face height (Na-ANS), more protrusive incisors (SNA-U1), and shorter cranial base (Ba-Na) and posterior cranial base (S-Ba) compared with the Chinese boys. In terms of ethnic comparison, the Chinese subjects presented shorter sagittal facial dimensions, a clockwise rotated mandible with a more acute gonial angle, and a convex facial profile with a less prominent nose and chin. However, overall vertical dimensions were similar. CONCLUSIONS: A 13-year-old combined male-female Chinese Bolton standard was created that demonstrated visually and with metric comparisons that Chinese and white clinically normal subjects have different craniofacial characteristics. These differences should be taken into consideration when an individualized orthodontic treatment plan is developed.

Transmission and maintenance cycle of Bartonella quintana among rhesus macaques, China.

We detected Bartonella quintana in 48.6% of captive rhesus macaques from an animal facility in Beijing, China. Prevalence of infection increased over the period of observation. Our findings suggest that macaques may serve as reservoir hosts for B. quintana and that Pedicinus obtusus lice might act as efficient vectors.

[Drinking-water type fluorosis treated with acupuncture of reinforcing kidney and activating spleen: a randomized controlled trial].

OBJECTIVE: To observe the impacts of acupuncture of reinforcing kidney and activating spleen on the excretion of urinary fluoride and pain of the patients with drinking-water type fluorosis. METHODS: The randomized controlled and single-blind trial was adopted. Seventy-two cases were randomized into an observation group and a control group, 36 cases in each one. In the observation group, acupuncture was applied at Pishu (BL 20), Shenshu (BL 23), Guanyuan (CV 4), Zusanli (ST 36), etc. , three treatments a week. In the control group, the Calcium Carbonate D3 tablets were prescribed for oral administration, 600 mg each time, twice a day. The duration of treatment was 2 months. The changes of the content of urinary fluoride and pain score (by VAS) before and after treatment between two groups were compared. RESULTS: The urinary fluoride excretion was increased obviously after treatment in the observation group (P < 0.01), which was superior apparently to that in the control group [(11.06 +/- 4.54) mg/L vs. (8.30 +/- 4.14) mg/L, P < 0.05]. After treatment, VAS score was reduced significantly in either group (both P < 0.01). The result in the observation group was lower remarkably than that in the control group (1.93 +/- 1.30 vs. 3.47 +/- 2.29, P < 0.01). CONCLUSION: Acupuncture achieves the significant efficacy on the promotion of urinary fluoride excretion and pain relieving of the patients with drinking-water type fluorosis in light of reinforcing kidney and activating spleen, which is superior to the oral administration of the calcium carbonate D3 tablets.

Validity and reliability of a method for assessment of cervical vertebral maturation.

OBJECTIVE: To evaluate the validity and reliability of the cervical vertebral maturation (CVM) method with a longitudinal sample. MATERIALS AND METHODS: Eighty-six cephalograms from 18 subjects (5 males and 13 females) were selected from the longitudinal database. Total mandibular length was measured on each film; an increased rate served as the gold standard in examination of the validity of the CVM method. Eleven orthodontists, after receiving intensive training in the CVM method, evaluated all films twice. Kendall's W and the weighted kappa statistic were employed. RESULTS: Kendall's W values were higher than 0.8 at both times, indicating strong interobserver reproducibility, but interobserver agreement was documented twice at less than 50%. A wide range of intraobserver agreement was noted (40.7%-79.1%), and substantial intraobserver reproducibility was proved by kappa values (0.53-0.86). With regard to validity, moderate agreement was reported between the gold standard and observer staging at the initial time (kappa values 0.44-0.61). However, agreement seemed to be unacceptable for clinical use, especially in cervical stage 3 (26.8%). CONCLUSIONS: Even though the validity and reliability of the CVM method proved statistically acceptable, we suggest that many other growth indicators should be taken into consideration in evaluating adolescent skeletal maturation.

Anti-EGFRvIII monoclonal antibody armed with 177Lu: in vivo comparison of macrocyclic and acyclic ligands.

INTRODUCTION: Monoclonal antibody (mAb) L8A4 binds specifically to the epidermal growth factor receptor variant III (EGFRvIII) that is present on gliomas but not on normal tissues, and is internalized rapidly after receptor binding. Because of the short range of its ß-emissions, labeling this mAb with (177)Lu would be an attractive approach for the treatment of residual tumor margins remaining after surgical debulking of brain tumors. MATERIALS AND METHODS: L8A4 mAb was labeled with (177)Lu using the acyclic ligands [(R)-2-amino-3-(4-isothiocyanatophenyl)propyl]-trans-(S,S)-cyclohexane-1,2-diamine-pentaacetic acid (CHX-A″-DTPA) and 2-(4-isothiocyanatobenzyl)-6-methyldiethylene-triaminepentaacetic acid (1B4M-DTPA), and the macrocyclic ligands S-2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane-tetraacetic acid (C-DOTA) and α-(5-isothiocyanato-2-methoxyphenyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (MeO-DOTA). Paired-label tissue distribution experiments were performed in athymic mice bearing subcutaneous EGFRvIII-expressing U87.ΔEGFR glioma xenografts over a period of 1 to 8 days to directly compare (177)Lu-labeled L8A4 to L8A4 labeled with (125)I using N-succinimidyl 4-guanidinomethyl-3-[(125)I]iodobenzoate ([(125)I]SGMIB). RESULTS: Except with C-DOTA, tumor uptake for the (177)Lu-labeled mAb was significantly higher than the co-administered radioiodinated preparation; however, this was also the case for spleen, liver, bone and kidneys. Tumor/normal tissue ratios for (177)Lu-1B4M-DTPA-L8A4 and, to an even greater extent, (177)Lu-MeO-DOTA-L8A4 were higher than those for [(125)I]SGMIB-L8A4 in most other tissues. CONCLUSIONS: Tumor and normal tissue distribution patterns for this anti-EGFRvIII mAb were dependent on the nature of the bifunctional chelate used for (177)Lu labeling. Optimal results were obtained with 1B4M-DTPA and MeO-DOTA, suggesting no clear advantage for acyclic vs. macrocyclic ligands for this application.

[Lu]-DOTA-Tyr-octreotate: A Potential Targeted Radiotherapeutic for the Treatment of Medulloblastoma.

Medulloblastoma, the most common pediatric brain tumor, is difficult to treat because conventional therapeutic approaches result in significant toxicity to normal central nervous system tissues, compromising quality of life. Given the fact that medulloblastomas express the somatostatin subtype 2 receptor, [(177)Lu-DOTA(0),Tyr(3)]octreotate ([(177)Lu]DOTA-TATE) could be a potentially useful targeted radiotherapeutic for the treatment of this malignancy. The current study was undertaken to evaluate this possibility in preclinical models of D341 MED human medulloblastoma by comparing the properties of [(177)Lu]DOTA-TATE to those of glucose-[(125)I-Tyr(3)]-octreotate ([(125)I]Gluc-TOCA), a radiopeptide previously shown to target this cell line. In vitro assays indicated that both labeled peptides exhibited similar cell-associated and internalized radioactivity after a 30-min incubation at 37°C; however, at the end of the 4 h incubation period, the internalized radioactivity for [(177)Lu]DOTA-TATE (6.22 " 0.75%) was nearly twice that for [(125)I]Gluc-TOCA (3.16 " 0.27%), with similar differences seen in total cell-associated radioactivity levels. Consistent with the results from the internalization assays, results from paired-label tissue distribution studies in athymic mice with subcutaneous D341 MED medulloblastoma xenografts showed a similar degree of tumor accumulation for [(177)Lu]DOTA-TATE and [(125)I]Gluc-TOCA at early time points but by 24 h, a more than 5-fold advantage was observed for the (177)Lu-labeled peptide. Tumor-to-normal tissue ratios generally were more favorable for [(177)Lu]DOTA-TATE at all time points, due in part to its lower accumulation in normal tissues except kidneys. Taken together, these results suggest that [(177)Lu]DOTA-TATE warrants further investigation as a targeted radiotherapeutic for medulloblastoma treatment.