Assessment of tumor hypoxia in spontaneous canine tumors after treatment with OMX, a novel H-NOX oxygen carrier, with [18F]FMISO PET/CT.

BACKGROUND: Hypoxia is a detrimental factor in solid tumors, leading to aggressiveness and therapy resistance. OMX, a tunable oxygen carrier from the heme nitric oxide/oxygen-binding (H-NOX) protein family, has the potential to reduce tumor hypoxia. [18F]Fluoromisonidazole ([18F]FMISO) positron emission tomography (PET) is the most widely used and investigated method for non-invasive imaging of tumor hypoxia. In this study, we used [18F]FMISO PET/CT (computed tomography) to assess the effect of OMX on tumor hypoxia in spontaneous canine tumors. RESULTS: Thirteen canine patients with various tumors (n = 14) were randomly divided into blocks of two, with the treatment groups alternating between receiving intratumoral (IT) OMX injection (OMX IT group) and intravenous (IV) OMX injection (OMX IV group). Tumors were regarded as hypoxic if maximum tumor-to-muscle ratio (TMRmax) was greater than 1.4. In addition, hypoxic volume (HV) was defined as the region with tumor-to-muscle ratio greater than 1.4 on [18F]FMISO PET images. Hypoxia was detected in 6/7 tumors in the OMX IT group and 5/7 tumors in the OMX IV injection group. Although there was no significant difference in baseline hypoxia between the OMX IT and IV groups, the two groups showed different responses to OMX. In the OMX IV group, hypoxic tumors (n = 5) exhibited significant reductions in tumor hypoxia, as indicated by decreased TMRmax and HV in [18F]FMISO PET imaging after treatment. In contrast, hypoxic tumors in the OMX IT group (n = 6) displayed a significant increase in [18F]FMISO uptake and variable changes in TMRmax and HV. CONCLUSIONS: [18F]FMISO PET/CT imaging presents a promising non-invasive procedure for monitoring tumor hypoxia and assessing the efficacy of hypoxia-modulating therapies in canine patients. OMX has shown promising outcomes in reducing tumor hypoxia, especially when administered intravenously, as evident from reductions in both TMRmax and HV in [18F]FMISO PET imaging.

Pulmonary Open, Robotic, and Thoracoscopic Lobectomy (PORTaL) Study: An Analysis of 5721 Cases.

OBJECTIVE: The aim of this study was to analyze outcomes of open lobectomy (OL), VATS, and robotic-assisted lobectomy (RL). SUMMARY BACKGROUND DATA: Robotic-assisted lobectomy has seen increasing adoption for treatment of early-stage lung cancer. Comparative data regarding these approaches is largely from single-institution case series or administrative datasets. METHODS: Retrospective data was collected from 21 institutions from 2013 to 2019. All consecutive cases performed for clinical stage IA-IIIA lung cancer were included. Neoadjuvant cases were excluded. Propensity-score matching (1:1) was based on age, sex, race, smoking-status, FEV1%, Zubrod score, American Society of Anesthesiologists score, tumor size, and clinical T and N stage. RESULTS: A total of 2391 RL, 2174 VATS, and 1156 OL cases were included. After propensity-score matching there were 885 pairs of RL vs OL, 1,711 pairs of RL vs VATS, and 952 pairs of VATS vs OL. Operative time for RL was shorter than VATS ( P < 0.0001) and OL ( P = 0.0004). Compared to OL, RL and VATS had less overall postoperative complications, shorter hospital stay (LOS), and lower transfusion rates (all P <0.02). Compared to VATS, RL had lower conversion rate ( P <0.0001), shorter hospital stay ( P <0.0001) and a lower postoperative transfusion rate ( P =0.01). RL and VATS cohorts had comparable postoperative complication rates. In-hospital mortality was comparable between all groups. CONCLUSIONS: RL and VATS approaches were associated with favorable perioperative outcomes compared to OL. Robotic-assisted lobectomy was also associated with a reduced length of stay and decreased conversion rate when compared to VATS.

Pulmonary Open, Robotic, and Thoracoscopic Lobectomy (PORTaL) Study: Survival Analysis of 6646 Cases.

OBJECTIVE: The aim of this study was to analyze overall survival (OS) of robotic-assisted lobectomy (RL), video-assisted thoracoscopic lobectomy (VATS), and open lobectomy (OL) performed by experienced thoracic surgeons across multiple institutions. SUMMARY BACKGROUND DATA: Surgeons have increasingly adopted RL for resection of early-stage lung cancer. Comparative survival data following these approaches is largely from single-institution case series or administrative data sets. METHODS: Retrospective data was collected from 21 institutions from 2013 to 2019. Consecutive cases performed for clinical stage IA-IIIA lung cancer were included. Induction therapy patients were excluded. The propensity-score method of inverse-probability of treatment weighting was used to balance baseline characteristics. OS was estimated using the Kaplan-Meier method. Multivariable Cox proportional hazard models were used to evaluate association among OS and relevant risk factors. RESULTS: A total of 2789 RL, 2661 VATS, and 1196 OL cases were included. The unadjusted 5-year OS rate was highest for OL (84%) followed by RL (81%) and VATS (74%); P =0.008. Similar trends were also observed after inverse-probability of treatment weighting adjustment (RL 81%; VATS 73%, OL 85%, P =0.001). Multivariable Cox regression analyses revealed that OL and RL were associated with significantly higher OS compared with VATS (OL vs. VATS: hazard ratio=0.64, P <0.001 and RL vs. VATS: hazard ratio=0.79; P =0.007). CONCLUSIONS: Our finding from this large multicenter study suggests that patients undergoing RL and OL have statistically similar OS, while the VATS group was associated with shorter OS. Further studies with longer follow-up are necessary to help evaluate these observations.

ACVR and ECVDI consensus statement: Reporting elements for toxicity criteria of the veterinary radiation therapy oncology group v2.0.

The toxicity criteria of the veterinary radiation therapy oncology group (VRTOG) version 2 guidelines are a substantial update to reflect significant advances in radiation oncology over the last three decades. Radiation therapy techniques provide precise and spatially accurate radiation delivery, which facilitates treating tumors in more anatomic locations and incorporating hypofractionated protocols. The purpose of this update is to aid radiation oncology teams in capturing and grading clinically relevant data that impacts the decision-making process in everyday practice and the assessment of clinical trials involving radiation therapy. A dedicated committee initially updated the criteria to include more anatomical sites and grades to characterize a broad spectrum of possible radiation-induced acute and late tissue changes. Through the revision process, which solicited and incorporated feedback from all radiation oncologists within the American College of Veterinary Radiology (ACVR) and specialists outside the ACVR, the authors endeavored to create a grading structure reflective of clinical decision-making in daily radiation oncology. The updated VRTOG v2 toxicity criteria guideline complements the updated Veterinary Cooperative Oncology Group-Common Terminology Criteria for Adverse Events (VCOG-CTCAE v2) guidelines. Because radiation oncology continues to progress rapidly, the VRTOG toxicity criteria should be regularly updated as adverse event data that will be collected following this update further informs the practice of radiation oncology.

MRI characteristics of canine prostatic neoplasia.

Magnetic resonance imaging (MRI) has been used to evaluate dogs with suspected prostatic neoplasia, however, published studies describing MRI characteristics of canine prostatic neoplasia are currently lacking. The aims of the current retrospective case series study were to describe MRI findings of the pelvic region in dogs with a histopathologic or cytologic diagnosis of prostatic neoplasia. Retrospective analysis of these images was then performed by a board-certified veterinary radiologist for shared imaging characteristics. The most consistent characteristics were heterogeneous hyperintensity of the tumor on T2-weighted images (10/10) and short tau inversion recovery images (10/10), prostatic capsular margin distortion by the tumor (10/10), cavitations (10/10), complete effacement of the prostatic architecture (9/10), neurovascular bundle (NVB) compression or invasion (9/10), heterogeneous isointensity of the tumor on T1-weighted images (9/10), and strong contrast enhancement of the tumor (8/10). Additional features included an overlying pattern of distorted radiating striations (7/10), regional lymphadenomegaly (5/10), mineralization within the mass (5/10), urinary bladder trigone involvement (6/10), and post-prostatic urethral involvement (7/10). These findings supported the use of MRI as an adjunct imaging modality for diagnosis and therapeutic planning of prostatic neoplasia and including prostatic neoplasia as a likely differential diagnosis for dogs with these MRI characteristics.

Metastatic perioral melanoma in a wild mountain gorilla (Gorilla beringei beringei).

A 30-year-old free-ranging female mountain gorilla (Gorilla beringei beringei) developed a perioral mass that was surgically debulked and diagnosed as malignant melanoma. After tumor recurrence, a canine melanoma vaccine was administered. However, the gorilla died shortly thereafter, and metastases to lymph nodes, lung, liver, and kidney were found post-mortem.

Efficacy of adjunctive therapy using Vizoovet in improving clinical signs of keratoconjunctivitis sicca in dogs: A pilot study.

OBJECTIVE: To assess the clinical safety and efficacy of adjunctive therapy using Vizoovet to ameliorate clinical signs of keratoconjunctivitis sicca (KCS) in dogs. ANIMALS STUDIED: Twenty client-owned dogs. PROCEDURES: Canine patients diagnosed with KCS were enrolled in this prospective study. Patients were randomly selected to receive either Vizoovet or GenTeal drops twice daily in addition to twice daily tacrolimus 0.03% solution. Data were collected from only one eye of each patient and included STT-1, IOP, TFBUT, and results of objective clinical scoring performed by pet owners. Statistical significance was set at P ≤ .05. RESULTS: In all, 20 dogs (20 eyes) were enrolled in this prospective randomized study. Females (n = 12; 60%) outnumbered males (n = 8; 40%) and all dogs were spayed/neutered. Mean age of all dogs was 10.6 ± 3.79 years. In both treatment groups, the improvement in STT-1 values over the course of the study was significant (P = .002). When comparing the STT-1 improvements between groups, no significance was found (P = .78). In both groups, the improvement in TFBUT was significant (P = .0018). When comparing the TFBUT improvements between groups, no significance was found (P = .14). Squinting, rubbing, ocular discharge, and medication administration scores all significantly improved throughout the course of the study; however, they did not differ significantly between groups. Throughout the study, no adverse side effects were noted clinically or by the pet owner in either group. CONCLUSIONS AND CLINICAL RELEVANCE: Adjunctive treatment with Vizoovet was as safe and effective as GenTeal drops at improving clinical signs of dry eye in dogs.

Outcome of Metastatic and Recurrent Ovarian Dysgerminoma Using Radiation Therapy and Chemotherapy in a Dog.

An 8 yr old female spayed poodle/terrier mixed-breed dog was referred for evaluation of a recurrent and metastatic ovarian dysgerminoma. A total dose of 20Gy was administered to both the mediastinal metastatic lesion and retroperitoneal recurrent dysgerminoma in five daily fractions of 4Gy. Acute side effects were mild and self-limiting. This was followed by several courses of chemotherapy using a variety of agents. Despite extensive disease, this patient was still alive at the time of publication, 524 days after presentation and 501 days following completion of radiation. This case report demonstrates tolerability and efficacy of palliative radiation and chemotherapy for this rare tumor type.

Long-term survival with stereotactic radiotherapy for imaging-diagnosed pituitary tumors in dogs.

Published studies on the use of stereotactic radiotherapy for dogs with pituitary tumors are limited. This retrospective observational study describes results of stereotactic radiotherapy for 45 dogs with imaging-diagnosed pituitary tumors. All dogs were treated at a single hospital during the period of December 2009-2015. The stereotactic radiotherapy was delivered in one 15 Gray (Gy) fraction or in three 8 Gy fractions. At the time of analysis, 41 dogs were deceased. Four were alive and censored from all survival analyses; one dog received 8 Gy every other day and was removed from protocol analyses. The median overall survival from first treatment was 311 days (95% confidence interval 226-410 days [range 1-2134 days]). Thirty-two dogs received 15 Gy (median overall survival 311 days; 95% confidence interval [range 221-427 days]), and 12 received 24 Gy on three consecutive days (median overall survival 245 days, 95% confidence interval [range 2-626 days]). Twenty-nine dogs had hyperadrenocorticism (median overall survival 245 days), while 16 had nonfunctional masses (median overall survival 626 days). Clinical improvement was reported in 37/45 cases. Presumptive signs of acute adverse effects within 4 months of stereotactic radiotherapy were noted in 10/45, and most had improvement spontaneously or with steroids. Late effects versus tumor progression were not discernable, but posttreatment blindness (2), hypernatremia (2), and progressive neurological signs (31) were reported. There was no statistical difference in median overall survival for different protocols. Patients with nonfunctional masses had longer median overall survival than those with hyperadrenocorticism (P = 0.0003). Survival outcomes with stereotactic radiotherapy were shorter than those previously reported with definitive radiation, especially for dogs with hyperadrenocorticism.

Insertion of Dengue E into lipid bilayers studied by neutron reflectivity and molecular dynamics simulations.

The envelope (E) protein of Dengue virus rearranges to a trimeric hairpin to mediate fusion of the viral and target membranes, which is essential for infectivity. Insertion of E into the target membrane serves to anchor E and possibly also to disrupt local order within the membrane. Both aspects are likely to be affected by the depth of insertion, orientation of the trimer with respect to the membrane normal, and the interactions that form between trimer and membrane. In the present work, we resolved the depth of insertion, the tilt angle, and the fundamental interactions for the soluble portion of Dengue E trimers (sE) associated with planar lipid bilayer membranes of various combinations of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-rac-glycerol (POPG), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), and cholesterol (CHOL) by neutron reflectivity (NR) and by molecular dynamics (MD) simulations. The results show that the tip of E containing the fusion loop (FL) is located at the interface of the headgroups and acyl chains of the outer leaflet of the lipid bilayers, in good agreement with prior predictions. The results also indicate that E tilts with respect to the membrane normal upon insertion, promoted by either the anionic lipid POPG or CHOL. The simulations show that tilting of the protein correlates with hydrogen bond formation between lysines and arginines located on the sides of the trimer close to the tip (K246, K247, and R73) and nearby lipid headgroups. These hydrogen bonds provide a major contribution to the membrane anchoring and may help to destabilize the target membrane.

Canine meningiomas treated with three-dimensional conformal radiation therapy require magnetic resonance imaging to avoid a geographic miss.

Exact target volume definition is an essential prerequisite for modern radiotherapy treatment planning. Contouring the gross tumor volume of brain tumors on computed tomography (CT) images coregistered with magnetic resonance images is standard practice in human medicine. In this retrospective study, including only cases with an imaging diagnosis of meningioma, we hypothesized that the gross tumor volume contoured from the contrast-enhanced magnetic resonance imaging (MRI) (gross tumor volume-MRI) is larger when compared to the gross tumor volume contoured using contrast-enhanced CT (gross tumor volume-CT). A total of 22 dogs were included in the study. Interestingly, there was a significant statistical difference between the gross tumor volume-CT and the gross tumor volume-MRI (P = 0.001). The gross tumor volume-MRI was larger than the gross tumor volume-CT in all, but two cases. The mean ratio between gross tumor volume-MRI and gross tumor volume-CT was 1.43 (range 0.84-4.00). The mean overlap between gross tumor volume-CT and gross tumor volume-MRI was 68% (range 22-86%), while a mean of 26% of the composite gross tumor volume was defined only by MRI (range 4-76%) and a mean of 6% only by CT (range 0-22%). These findings suggest that CT and MRI are complementary modalities in radiation planning of meningiomas and their composite volume should be used to avoid geographical miss of neoplastic tissue. When the MRI is not available for planning, a margin of 0.3 cm around the gross tumor volume-CT could reduce the probability of a geographical miss. However, such numerical correction cannot be applied to the clinical practice until it is validated in a properly designed treatment planning study.

Consensus recommendations on standardized magnetic resonance imaging protocols for multicenter canine brain tumor clinical trials.

The National Cancer Institute Comparative Brain Tumor Consortium, Patient Outcomes Working Group, propose a consensus document in support of standardized magnetic resonance imaging protocols for canine brain tumor clinical trials. The intent of this manuscript is to address the widely acknowledged need to ensure canine brain tumor imaging protocols are relevant and have sufficient equivalency to translate to human studies such that: (1) multi-institutional studies can be performed with minimal inter-institutional variation, and (2) imaging protocols are consistent with human consensus recommendations to permit reliable translation of imaging data to human clinical trials. Consensus recommendations include pre- and postcontrast three-dimensional T1-weighted images, T2-weighted turbo spin echo in all three planes, T2*-weighted gradient recalled echo, T2-weighted fluid attenuated inversion recovery, and diffusion weighted imaging/diffusion tensor imaging in transverse plane; field of view of ≤150 mm; slice thickness of ≤2 mm, matrix ≥ 256 for two-dimensional images, and 150 or 256 for three-dimensional images.

Method for measuring the unbinding energy of strongly-bound membrane-associated proteins.

We describe a new method to measure the activation energy for unbinding (enthalpy ΔH*u and free energy ΔG*u) of a strongly-bound membrane-associated protein from a lipid membrane. It is based on measuring the rate of release of a liposome-bound protein during centrifugation on a sucrose gradient as a function of time and temperature. The method is used to determine ΔH*u and ΔG*u for the soluble dengue virus envelope protein (sE) strongly bound to 80:20 POPC:POPG liposomes at pH5.5. ΔH*u is determined from the Arrhenius equation whereas ΔG*u is determined by fitting the data to a model based on mean first passage time for escape from a potential well. The binding free energy ΔGb of sE was also measured at the same pH for the initial, predominantly reversible, phase of binding to a 70:30 PC:PG lipid bilayer. The unbinding free energy (20±3kcal/mol, 20% PG) was found to be roughly three times the binding energy per monomer, (7.8±0.3kcal/mol for 30% PG, or est. 7.0kcal/mol for 20% PG). This is consistent with data showing that free sE is a monomer at pH5.5, but assembles into trimers after associating with membranes. This new method to determine unbinding energies should be useful to understand better the complex interactions of integral monotopic proteins and strongly-bound peripheral membrane proteins with lipid membranes.

MicroRNA profiling of dogs with transitional cell carcinoma of the bladder using blood and urine samples.

BACKGROUND: Early signs of canine transitional cell carcinoma (TCC) are frequently assumed to be caused by other lower urinary tract diseases (LUTD) such as urinary tract infections, resulting in late diagnosis of TCC which could be fatal. The development of a non-invasive clinical test for TCC could dramatically reduce mortality. To determine whether microRNAs (miRNAs) can be used as non-invasive diagnostic biomarkers, we assessed miRNA expression in blood and/or urine from dogs with clinically normal bladders (n = 28), LUTD (n = 25), and TCC (n = 17). Expression levels of 5 miRNA associated with TCC pathophysiology (miR-34a, let-7c, miR-16, miR-103b, and miR-106b) were assessed by quantitative real-time PCR. RESULTS: Statistical analyses using ranked ANOVA identified significant differences in miR-103b and miR-16 levels between urine samples from LUTD and TCC patients (miR-103b, p = 0.002; and miR-16, p = 0.016). No statistically significant differences in miRNA levels were observed between blood samples from LUTD versus TCC patients. Expression levels of miR-34a trended with miR-16, let-7c, and miR-103b levels in individual normal urine samples, however, this coordination was completely lost in TCC urine samples. In contrast, co-ordination of miR-34a, miR-16, let-7c, and miR-103b expression levels was maintained in blood samples from TCC patients. CONCLUSIONS: Our combined data indicate a potential role for miR-103b and miR-16 as diagnostic urine biomarkers for TCC, and that further investigation of miR-103b and miR-16 in the dysregulation of coordinated miRNA expression in bladder carcinogenesis is warranted.

A NOVEL, REMOVABLE, CERROBEND, BEAM-BLOCKING DEVICE FOR RADIATION THERAPY OF THE CANINE HEAD AND NECK: PILOT STUDY.

Radiation therapy of the head and neck can result in mucositis and other acute affects in the oral cavity. This prospective pilot study evaluated a novel, intraoral, beam-blocking device for use during imaging and therapeutic procedures. The beam-blocking device was made from a metal alloy inserted into a coated frozen dessert mold (Popsicle® Mold, Cost Plus World Market, Oakland, CA). The device was designed so that it could be inserted into an outer shell, which in turn allowed it to be placed or removed depending on the need due to beam configuration. A Farmer type ionization chamber and virtual water phantom were used to assess effects of field size on transmission. Six large breed cadaver dogs, donated by the owner after death, were recruited for the study. Delivered dose at the dorsal and ventral surfaces of the device, with and without the alloy block in place, were measured using radiochromic film. It was determined that transmission was field size dependent with larger field sizes leading to decreased attenuation of the beam, likely secondary to scatter. The mean and median transmission on the ventral surface without the beam-blocking device was 0.94 [range 0.94-0.96]. The mean and median transmission with the beam-blocking device was 0.52 [range 0.50-0.57]. The mean and median increase in dose due to backscatter on the dorsal surface of the beam-blocking device was 0.04 [range 0.02-0.04]. Findings indicated that this novel device can help attenuate radiation dose ventral to the block in dogs, with minimal backscatter.

Molecular basis of endosomal-membrane association for the dengue virus envelope protein.

Dengue virus is coated by an icosahedral shell of 90 envelope protein dimers that convert to trimers at low pH and promote fusion of its membrane with the membrane of the host endosome. We provide the first estimates for the free energy barrier and minimum for two key steps in this process: host membrane bending and protein-membrane binding. Both are studied using complementary membrane elastic, continuum electrostatics and all-atom molecular dynamics simulations. The predicted host membrane bending required to form an initial fusion stalk presents a 22-30 kcal/mol free energy barrier according to a constrained membrane elastic model. Combined continuum and molecular dynamics results predict a 15 kcal/mol free energy decrease on binding of each trimer of dengue envelope protein to a membrane with 30% anionic phosphatidylglycerol lipid. The bending cost depends on the preferred curvature of the lipids composing the host membrane leaflets, while the free energy gained for protein binding depends on the surface charge density of the host membrane. The fusion loop of the envelope protein inserts exactly at the level of the interface between the membrane's hydrophobic and head-group regions. The methods used in this work provide a means for further characterization of the structures and free energies of protein-assisted membrane fusion.

End-anchored polymers in good solvents from the single chain limit to high anchoring densities.

An increasing number of applications utilize grafted polymer layers to alter the interfacial properties of solid substrates, motivating refinement in our theoretical understanding of such layers. To assess existing theoretical models of them, we have investigated end-anchored polymer layers over a wide range of grafting densities, σ, ranging from a single chain to high anchoring density limits, chain lengths ranging over two orders of magnitude, for very good and marginally good solvent conditions. We compare Monte Carlo and molecular dynamics simulations, numerical self-consistent field calculations, and experimental measurements of the average layer thickness, h, with renormalization group theory, the Alexander-de Gennes mushroom theory, and the classical brush theory. Our simulations clearly indicate that appreciable inter-chain interactions exist at all simulated areal anchoring densities so that there is no mushroom regime in which the layer thickness is independent of σ. Moreover, we find that there is no high coverage regime in which h follows the predicted scaling, h ∼ Nσ1/3, for classical polymer brushes either. Given that no completely adequate analytic theory seems to exist that spans wide ranges of N and σ, we applied scaling arguments for h as a function of a suitably defined reduced anchoring density, defined in terms of the solution radius of gyration of the polymer chains and N. We find that such a scaling approach enables a smooth, unified description of h in very good solvents over the full range of anchoring density and chain lengths, although this type of data reduction does not apply to marginal solvent quality conditions.

FEASIBILITY FOR USING HYPOFRACTIONATED STEREOTACTIC VOLUMETRIC MODULATED ARC RADIOTHERAPY (VMAT) WITH ADAPTIVE PLANNING FOR TREATMENT OF THYMOMA IN RABBITS: 15 CASES.

Thymoma is a relatively common tumor in rabbits. Treatment with surgery, radiation therapy, and chemotherapy alone or in combination has been reported with varying outcomes. Stereotactic volumetric modulated arc radiotherapy delivered in a hypofractionated manner allows high doses of radiation to be delivered to the target volume while allowing sparing of adjacent critical structures. This therapy is ideally suited for thymomas in rabbits given their size, the difficulty of multiple anesthesia episodes and the complexity of the radiotherapy plans required due to the tumor's proximity to the heart, lungs, and mediastinal structures. Fifteen rabbits with thymoma were prospectively recruited for this observational, single institution, single arm clinical study. All rabbits were imaged with both computed tomography (CT) and magnetic resonance imaging (MRI). A total dose of 40 Gy in six fractions was delivered using a single arc over an 11-day period with repeat CT simulation done every other fraction for adaptive planning. Follow-up evaluation was done through repeat CT and MRI imaging and revealed complete responses using the Response Evaluation Criteria in Solid Tumors (RECIST) criteria. Two rabbits had died at 618 and 718 days, 10 were alive and three were lost to follow-up. Observed acute and late effects were graded according to the Veterinary Radiation Therapy Oncology Group (VRTOG) criteria and were found to be minimal.

ESTABLISHMENT OF REFERENCE INTERVALS FOR HEMATOLOGY AND BIOCHEMISTRY ANALYTES IN A CAPTIVE COLONY OF STRAW-COLORED FRUIT BATS (EIDOLON HELVUM).

Straw-colored fruit bats (Eidolon helvum) are an ecologically important species of megachiropteran bat that are common both in captivity and in the wild. This study attempts to determine reference intervals from a group of 45 captive individuals for a variety of hematologic and biochemistry parameters. Most of the values are similar to values previously seen in other pteropodid bat species. Differences included a lower than expected reference interval for the total white blood cell count, a wider reference interval for glucose, and a higher reference interval for 25-hydroxyvitamin D. Establishing reference intervals for hematologic and biochemistry analytes for bats that were maintained on the same diet and under the same husbandry parameters for several years will help in the future assessment of other bats maintained in a similar manner.

Hydrogen Exchange Mass Spectrometry of Proteins at Langmuir Monolayers.

Hydrogen exchange (HX) mass spectrometry (MS) is valuable for providing conformational information for proteins/peptides that are very difficult to analyze with other methods such as peripheral membrane proteins and peptides that interact with membranes. We developed a new type of HX MS measurement that integrates Langmuir monolayers. A lipid monolayer was generated, a peptide or protein associated with it, and then the monolayer-associated peptide or protein was exposed to deuterium. The deuterated species was recovered from the monolayer, digested, and deuterium incorporation monitored by MS. Test peptides showed that deuterium recovery in an optimized protocol was equivalent to deuterium recovery in conventional solution HX MS. The reproducibility of the measurements was high, despite the requirement of generating a new monolayer for each deuterium labeling time. We validated that known conformational changes in the presence of a monolayer/membrane could be observed with the peptide melittin and the myristoylated protein Arf-1. Results in an accompanying paper show that the method can reveal details of conformational changes in a protein (HIV-1 Nef), which adopts a different conformation, depending on whether or not it is able to insert into the lipid layer. Overall, the HX MS Langmuir monolayer method provided new and meaningful conformational information for proteins that associate with lipid layers. The combination of HX MS results with neutron or X-ray reflection of the same proteins in Langmuir monolayers can be more informative than the isolated use of either method.