Antimicrobial peptides (AMPs) constitute promising alternatives to classical antibiotics for the treatment of drug-resistant infections, which are a rapidly emerging global health challenge. However, our understanding of the structure-function relationships of AMPs is limited, and we are just beginning to rationally engineer peptides in order to develop them as therapeutics. Here, we leverage a physicochemical-guided peptide design strategy to identify specific functional hotspots in the wasp-derived AMP polybia-CP and turn this toxic peptide into a viable antimicrobial. Helical fraction, hydrophobicity, and hydrophobic moment are identified as key structural and physicochemical determinants of antimicrobial activity, utilized in combination with rational engineering to generate synthetic AMPs with therapeutic activity in a mouse model. We demonstrate that, by tuning these physicochemical parameters, it is possible to design nontoxic synthetic peptides with enhanced sub-micromolar antimicrobial potency in vitro and anti-infective activity in vivo. We present a physicochemical-guided rational design strategy to generate peptide antibiotics.

Purpose Although gemcitabine is a mainstay of pancreatic cancer therapy, it is only moderately effective, and it would be desirable to measure drug uptake in patients. 1-(2′-deoxy-2′-fluoroarabinofuranosyl) cytosine (FAC), is an analog of gemcitabine, and when labeled with F-18, it may be a potential surrogate PET tracer for the drug. Procedures [18F]FAC was synthesized to a radiochemical purity of >96 %. The human tumor lines AsPC1, BxPC3, Capan-1, Panc1, and MiaPaca2 were grown orthotopically in nude mice. KPC mice that conditionally express oncogenic K-ras and p53 mutations in pancreatic tissue were also used. The intra-tumoral distributions of [14C]gemcitabine and [18F]FAC were mapped with autoradiography. The inter-tumor correlation between [14C]gemcitabine and [18F]FAC was established in the orthotopic tumors. Expression of the equilibrative and concentrative nucleoside transporters (ENT, CNT) in vitro was detected by western blotting. Drug uptake was characterized in vitro using [3H]gemcitabine and the effect of transporter inhibition on gemcitabine and FAC uptake was investigated. The relative affinity of cells for gemcitabine and FAC was tested in competition assays. The cell lines differed in sensitivity to transport inhibitors and in competition studies. There was a good in vivo correlation between the total uptake of [18F]FAC and [14C]gemcitabine, measured across all orthotopic tumors. Using the KPC and BxPC3 models, we found that [14C]gemcitabine and [18F]FAC were largely co-localized. Conclusions In the lines examined here, [18F]FAC uptake correlates well with gemcitabine in vivo, supporting the notion that [18F]FAC can serve as a PET radiotracer surrogate to determine the uptake and distribution of gemcitabine within pancreatic tumors.

Physiologic changes during development, aging, and pregnancy may affect clinical parameters. Previously available reference values have been based on samples that may include wild and captive marmosets, with little representation of geriatricor pregnant animals. Establishing reference values under various conditions would support better recognition of pathologic conditions in marmosets. One hundred and forty-seven (70 males and 77 females) healthy marmosets from a research colony were included in this study. Exclusion criteria were abnormal physical exam findings at the time of blood sampling, chronicmedications, or clinical or pathologic evidence of disease. Reference intervals were calculated for serum chemistry andhematology. Using metadata, samples were classified based on age, sex, colony source and pregnancy status. Multiple testsindicated significant differences with varying effect sizes, indicating that developing reference intervals based on metadatacan be useful. Across all the comparisons, medium or large effect sizes were observed most frequently in blood urea nitrogen (BUN), calcium, total protein, alkaline phosphatase (ALP), weight and serum albumin. We report normative clinical pathologic data for captive common marmosets through all life stages and reproductive status. Significant differences were observed in most parameters when stratifying data based on age, sex, colony source, or pregnancy, suggesting that developing reference intervals considering this information is important for clinicians.

Purpose To evaluate the feasibility of delivering experimental radiotherapy to tumors in the mouse pancreas. Imaging and treatment were performed using combined CT (computed tomography)/orthovoltage treatment with a rotating gantry. Methods and Materials After intraperitoneal administration of radiopaque iodinated contrast, abdominal organ delineation was performed by X-ray CT. With this technique we delineated the pancreas, and both orthotopic xenografts and genetically engineered disease. CT imaging was validated by comparison with magnetic resonance (MR) imaging. Therapeutic radiation was delivered via a 1 cm diameter field. Selective X-ray radiation therapy (XRT) of the non-invasively defined orthotopic mass was confirmed using γH2AX staining. Mice could tolerate a dose of 15 Gy when the field was centered on the pancreas tail, and treatment was delivered as a continuous 360-degree arc. This strategy was then used for radiation therapy planning for selective delivery of therapeutic XRT to orthotopic tumors. Results Tumor growth delay after 15 Gy was monitored, using CT and ultrasound to determine the tumor volume at various times post-treatment. Our strategy enables the use of clinical radiation oncology approaches to treat experimental tumors in the pancreas of small animals for the first time. We demonstrate that delivery of 15 Gy from a rotating gantry minimizes background healthy tissue damage and significantly retards tumor growth. Conclusions This advance permits evaluation of radiation planning and dosing parameters. Accurate non-invasive longitudinal imaging and monitoring of tumor progression and therapeutic response in pre-clinical models is now possible, and can be expected to more effectively evaluate pancreatic cancer disease and therapeutic response.

Inclusion body nephropathy (IBN) and kidney fibrosis in aged immunodeficient mice and, to lesser extent, in immunocompetent mice have been recently linked to infection of mouse kidney parvovirus (MKPV), also known as murine chapparvovirus (MuCPV). Knowledge about its prevalence and the complete genome sequence of more MKPV strains is essential for understanding phylogenetic relationships and pathogenicity among MKPV strains. In the present study using PCR and genome walking, we determined the complete 4440-nucleotide genome of a new MKPV strain, namely MIT-WI1, which was identified in IBN-affected Il2rg −/-Rag2 −/c-Kit W-sh/W-sh mice housed in the vivarium at Whitehead Institute for Biomedical Research (WI). The overall nucleotide (>94%) and deduced amino acid sequences (>98%) of p10, p15, NS1 (replicase), NS2 and VP1 (capsid protein) within the MIT-WI1 genome, are closely related to MKPV/MuCPV strains described in laboratory and wild Mus musculus mice. In addition, PCR and qPCR assays using newly designed primers conserved among the known MKPV/MuCPV genomes were developed and utilized to assess MKPV status in selected laboratory mice. MKPV was also detected in immunodeficient (NSG) and immunocompetent (Crl:CD1(ICR), UTX flox) mouse strains/stocks. The abundance of the MKPV genome copies was significantly correlated with the severity of IBN. Our data indicate that MKPV is present in selected mouse strains/stocks, and provides new insights into the genome evolution of MKPV.

No abstract

Pancreatic cancer is one of the leading causes of cancer-related death in the United States. Gemcitabine is a common treatment, but response rates are low, perhaps due in part to tumor hypoxia. We utilized (14)C-labeled gemcitabine to map distribution of the drug with respect to perfused and hypoxic regions of the tumor microenvironment in two orthotopic xenograft models of pancreatic cancer. There was only a slight reduction in gemcitabine in hypoxic areas, with ∼78% of the drug present in hypoxic compared to perfused areas. In addition, only a 4% reduction in gemcitabine was measured at >100 μm from perfused blood vessels. Thus, despite significant areas of hypoxia in these tumors, gemcitabine distribution is relatively homogenous. Ours is the first study to directly measure gemcitabine distribution within tumor tissue, demonstrating that in these models, tumor tissue does not represent a barrier to gemcitabine penetration.

HistoryA 12-year-old 7.4-kg (16.3-lb) castrated male mixed-breed dog was evaluated because of a 2-day history of vomiting, anorexia, lethargy, tenesmus, and stranguria. The dog had a history of bilateral perineal hernias. The right-sided hernia had been surgically repaired approximately 3 years ago. The left-sided hernia had been managed medically with stool softeners and periodic digital evacuation of feces prior to initial evaluation.On physical examination, the dog had a tense abdomen, with signs of pain on abdominal palpation; individual abdominal organs could not be evaluated on abdominal palpation. There was a soft, painful swelling present in the left perineal region. On digital rectal examination, a rectal diverticulum was palpable on the left side. Complete blood count revealed mild, mature neutrophilia (22,990 neutrophils/µL; reference range, 5,500 to 16,900 neutrophils/µL), monocytosis (3,030 monocytes/µL; reference range, 300 to 2,000 monocytes/µL), and thrombocytosis (579,000 platelets/µL; reference range, 175,000 to 500,000 platelets/µL). Serum biochemical analysis revealed a mildly high serum alkaline phosphatase activity (376 U/L; reference range, 23 to 212 U/L). All other hematologic parameters were within reference limits. Radiographs of the abdominopelvic area were obtained (Figure 1).Determine whether additional imaging studies are required, or make your diagnosis from Figure 1-then turn the page →