RT-QuIC detection of chronic wasting disease prion in platelet samples of white-tailed deer.

BACKGROUND: Chronic wasting disease (CWD) is a prion disease of captive and free-ranging cervids. Currently, a definitive diagnosis of CWD relies on immunohistochemistry detection of PrPSc in the obex and retropharyngeal lymph node (RPLN) of the affected cervids. For high-throughput screening of CWD in wild cervids, RPLN samples are tested by ELISA followed by IHC confirmation of positive results. Recently, real-time quacking-induced conversion (RT-QuIC) has been used to detect CWD positivity in various types of samples. To develop a blood RT-QuIC assay suitable for CWD diagnosis, this study evaluated the assay sensitivity and specificity with and without ASR1-based preanalytical enrichment and NaI as the main ionic component in assay buffer. RESULTS: A total of 23 platelet samples derived from CWD-positive deer (ELISA + /IHC +) and 30 platelet samples from CWD-negative (ELISA-) deer were tested. The diagnostic sensitivity was 43.48% (NaCl), 65.22% (NaI), 60.87% (NaCl-ASR1) or 82.61% (NaI-ASR1). The diagnostic specificity was 96.67% (NaCl), 100% (NaI), 100% (NaCl-ASR1), or 96.67% (NaI-ASR1). The probability of detecting CWD prion in platelet samples derived from CWD-positive deer was 0.924 (95% CRI: 0.714, 0.989) under NaI-ASR1 experimental condition and 0.530 (95% CRI: 0.156, 0.890) under NaCl alone condition. The rate of amyloid formation (RFA) was greatest under the NaI-ASR1 condition at 10-2 (0.01491, 95% CRI: 0.00675, 0.03384) and 10-3 (0.00629, 95% CRI: 0.00283, 0.01410) sample dilution levels. CONCLUSIONS: Incorporation of ASR1-based preanalytical enrichment and NaI as the main ionic component significantly improved the sensitivity of CWD RT-QuIC on deer platelet samples. Blood test by the improved RT-QuIC assay may be used for antemortem and postmortem diagnosis of CWD.

The Impact of Surgical Delay in Primary Cutaneous Melanoma: A Systematic Review.

BACKGROUND AND OBJECTIVES: The prognosis of patients diagnosed with melanoma is highly dependent on staging, early detection, and early intervention. In this systematic review, the authors aimed to investigate the impact of surgical delay (time between diagnostic biopsy and definitive surgical excision) on melanoma-specific outcomes. MATERIAL AND METHODS: A systematic review was conducted from Embase (1974-present), MEDLINE (1946-present), Cochrane Central Register of Controlled Trials (2005-present), Scopus, and Web of Science. A total of 977 studies were included for review after removal of duplicates. A total of 10 studies were included for final analysis. RESULTS: In total, 70% (7/10) of the studies found that longer wait times between initial biopsy and surgical intervention are correlated with lower overall survival. Among the 9 studies that reported overall survival as a percentage, the median and SD overall survival was 82% ± 5.87. CONCLUSION: There is evidence that prolonged surgical delay in patients diagnosed with Stage I cutaneous melanoma is associated with worsened overall mortality, whereas the effect of surgical delay on overall mortality in Stages II and III melanomas is uncertain. Future prospective studies and randomized clinical trials are needed to better define the appropriate surgical wait times between biopsy and surgical treatment.

A microfluidic biosensor for the diagnosis of chronic wasting disease.

Cervids are affected by a neurologic disease that is always fatal to individuals and has population effects. This disease is called chronic wasting disease (CWD) and is caused by a misfolded prion protein. The disease is transmitted via contact with contaminated body fluids and tissue or exposure to the environment, such as drinking water or food. Current CWD diagnosis depends on ELISA screening of cervid lymph nodes and subsequent immunohistochemistry (IHC) confirmation of ELISA-positive results. The disease has proven to be difficult to control in part because of sensitivity and specificity issues with the current test regimen. We have investigated an accurate, rapid, and low-cost microfluidic microelectromechanical system (MEMS) biosensing device for the detection of CWD pathologic prions in retropharyngeal lymph nodes (RLNs), which is the current standard type of CWD diagnostic sample. The device consists of three novel regions for concentrating, trapping, and detecting the prion. The detection region includes an array of electrodes coated with a monoclonal antibody against pathologic prions. The experimental conditions were optimized using an engineered prion control antigen. Testing could be completed in less than 1 hour with high sensitivity and selectivity. The biosensor detected the engineered prion antigen at a 1:24 dilution, while ELISA detected the same antigen at a 1:8 dilution. The relative limit of detection (rLOD) of the biosensor was a 1:1000 dilution of a known strong positive RLN sample, whereas ELISA showed a rLOD of 1:100 dilution. Thus, the biosensor was 10 times more sensitive than ELISA, which is the currently approved CWD diagnostic test. The biosensor's specificity and selectivity were confirmed using known negative RPLN samples, a negative control antibody (monoclonal antibody against bovine coronavirus BCV), and two negative control antigens (bluetongue virus and Epizootic hemorrhagic disease virus). The biosensor's ability to detect pathogenic prions was verified by testing proteinase-digested positive RLN samples.

ChatGPT offers an editorial on the opportunities for chatbots in dermatologic research and patient care.

ChatGPT is a chatbot developed by OpenAI, an artificial intelligence research laboratory, that is trained on massive-scale internet text data to understand a broad range of language styles and topics. As a mature, conversational chatbot, ChatGPT can respond to follow-up questions and produce coherent primary texts based on the user's request. We explore the opportunities and risks of integrating chatbots into dermatologic patient care and research while presenting ChatGPT's response to the same question.

Benefit and toxicity of programmed death-1 blockade vary by ethnicity in patients with advanced melanoma: an international multicentre observational study.

BACKGROUND: Programmed cell death receptor-1 (PD-1) monotherapy is a standard treatment for advanced cutaneous melanoma, but its efficacy and toxicity are defined in white populations and remain poorly characterized in other ethnic groups, such as East Asian, Hispanic and African. OBJECTIVES: To determine the efficacy and toxicity of PD-1 monotherapy in different ethnic groups. METHODS: Clinical data for patients with unresectable or advanced melanoma treated with anti-PD-1 monotherapy between 2009 and 2019 were collected retrospectively from five independent institutions in the USA, Australia and China. Tumour response, survival and immune-related adverse events (irAEs) were compared by ethnicity (white vs. East Asian/Hispanic/African) across different melanoma subtypes: nonacral cutaneous (NAC)/unknown primary (UP) and acral/mucosal/uveal. RESULTS: In total, 1135 patients were included. White patients had significantly higher objective response rate (ORR) [54%, 95% confidence interval (CI) 50-57% vs. 20%, 95% CI 13-28%; adjusted P < 0·001] and longer progression-free survival (14·2 months, 95% CI 10·7-20·3 vs. 5·4 months, 95% CI 4·5-7·0; adjusted P < 0·001) than East Asian, Hispanic and African patients in the NAC and UP subtypes. White ethnicity remained independently associated with a higher ORR (odds ratio 4·10, 95% CI 2·48-6·81; adjusted P < 0·001) and longer PFS (hazard ratio 0·58, 95% CI 0·46-0·74; adjusted P < 0·001) in multivariate analyses after adjustment for age, sex, primary anatomical location, metastasis stage, baseline lactate dehydrogenase level, mutational status and prior systemic treatment. White and East Asian/Hispanic/African patients shared similar ORR and progression-free survival in acral/mucosal/uveal melanomas. Similar melanoma-subtype-specific ethnic discrepancies were observed in complete response rate and overall survival. White patients had higher rates of gastrointestinal irAEs but lower rates of endocrine, liver and other rare types of irAEs. These differences in irAEs by ethnicity were not attributable to varying melanoma subtypes. CONCLUSIONS: Ethnic discrepancy in clinical benefit is specific to melanoma subtype, and East Asian, Hispanic and African patients with NAC and UP melanomas have poorer clinical benefits than previously recognized. The ethnic discrepancy in toxicity observed across different melanoma subtypes warrants an ethnicity-based irAE surveillance strategy. More research is needed to elucidate the molecular and immunological determinants of these differences. What is already known about this topic? There is a great difference in response to immunotherapy between different subtypes of melanoma (cutaneous, mucosal, acral and uveal) in patients with advanced disease. What does this study add? Our data show for the first time that there are differences between different ethnic groups in terms of both response and toxicity to immunotherapy beyond the well-appreciated discrepancies due to melanoma subtype.

Improving annual albuminuria testing for individuals with diabetes.

BACKGROUND: Annual albuminuria screening detects the early stages of nephropathy in individuals with diabetes. Because early detection of albuminuria allows for interventions that lower the risk of developing chronic kidney disease, guidelines recommend annual testing for all individuals with type 2 diabetes mellitus and for those with type 1 diabetes for at least 5 years. However, at the Eskind Diabetes Clinic at the Vanderbilt University Medical Center, testing occurred less frequently than desired. METHODS: A quality improvement team first analysed the clinic's processes, identifying the lack of a systematic approach to testing as the likely cause for the low rate. The team then implemented two successive interventions in a pilot of patients seen by nurse practitioners in the clinic. In the first intervention, staff used a dashboard within the electronic health record while triaging each patient, pending an albuminuria order if testing had not been done within the past year. In the second intervention, clinic leadership sent daily reminders to the triage staff. A statistical process control chart tracked monthly testing rates. RESULTS: After 6 months, annual albuminuria testing increased from a baseline of 69% to 82%, with multiple special-cause signals in the control chart. CONCLUSIONS: This project demonstrates that a series of simple interventions can significantly impact annual albuminuria testing. This project's success likely hinged on using an existing workflow to systematically determine if a patient was due for testing and prompting the provider to sign a pended order for an albuminuria test. Other diabetes/endocrinology and primary care clinics can likely implement a similar process and so improve testing rates in other settings. When coupled with appropriate interventions to reduce the development of chronic kidney disease, such interventions would improve patient outcomes, in addition to better adhering to an established quality metric.

A Roadmap to Implementing Venous Thromboembolism Risk Stratification and Mitigation.

INTRODUCTION: Venous thromboembolism (VTE) is a life-threatening postoperative complication that carries high morbidity and mortality for plastic surgery patients. In 2011, the American Society of Plastic Surgeons recommended the adoption of a VTE risk stratification and mitigation; however, successful implementation of VTE prophylaxis protocols has not been well described. To address and reduce the VTE burden at our academic center, a risk assessment protocol was implemented for patients undergoing outpatient plastic surgery procedures. METHOD: All patients who received outpatient plastic surgery between August 2018 and July 2019 were eligible for the VTE modified Caprini risk assessment screening. Sampling of practice patterns was done by chart review from the first week of each month. The study was divided into 3 phases to assess the relationship of screening compliance rates with each protocol change. Compliance was defined as completion of VTE Caprini screening with documentation in patients' charts. RESULTS: Over the 12-month study period, 277 patients met the inclusion criteria. From August to November 2018 (phase 1), patients were screened at the initial clinic visit with an average compliance rate of 11.1%. In December 2018 (phase 2), patients were screened on the day of surgery, with an average compliance rate of 47.1%. From January to July 2019 (phase 3), surgeons recorded the numerical Caprini score into the patient's electronic medical record with a subsequent compliance rate of 61.3%. The overall compliance during the 12 months was 44.8%. The median calculated Caprini score for this population was 4 (range, 1-7). CONCLUSIONS: Standardization of VTE risk assessment is vital for patient safety and outcomes. Successful implementation and long-term protocol sustainability are not a simple goal. In this study, protocol compliance greatly improved after tailoring the guidelines to the specific institutional needs and workflow. These results reinforce the importance of continuous protocol review and modification to ensure optimal departmental buy-in and sustainability.

Early Use of High-Dose Glucocorticoid for the Management of irAE Is Associated with Poorer Survival in Patients with Advanced Melanoma Treated with Anti-PD-1 Monotherapy.

PURPOSE: Programmed cell death receptor-1 (PD-1) inhibitors are frontline therapy in advanced melanoma. Severe immune-related adverse effects (irAEs) often require immunosuppressive treatment with glucocorticoids (GCCs), but GCC use and its correlation with patient survival outcomes during anti-PD-1 monotherapy remains unclear. EXPERIMENTAL DESIGN: In this multicenter retrospective analysis, patients treated with anti-PD-1 monotherapy between 2009 and 2019 and detailed GCC use, data were identified from five independent cohorts, with median follow-up time of 206 weeks. IrAEs were tracked from the initiation of anti-PD-1 until disease progression, initiation of a new therapy, or last follow-up. Correlations between irAEs, GCC use, and survival outcomes were analyzed. RESULTS: Of the entire cohort of 947 patients, 509 (54%) developed irAEs. In the MGH cohort [irAE(+) n = 90], early-onset irAE (within 8 weeks of anti-PD-1 initiation) with high-dose GCC use (≥60-mg prednisone equivalent once a day) was independently associated with poorer post-irAE PFS/OS (progression-free survival/overall survival) [post-irAE PFS: HR, 5.37; 95% confidence interval (CI), 2.10-13.70; P < 0.001; post-irAE OS: HR, 5.95; 95% CI, 2.20-16.09; P < 0.001] compared with irAEs without early high-dose GCC use. These findings were validated in the combined validation cohort [irAE(+) n = 419, post-irAE PFS: HR, 1.69; 95% CI, 1.04-2.76; P = 0.04; post-irAE OS: HR, 1.97; 95% CI, 1.15-3.39; P = 0.01]. Similar findings were also observed in the 26-week landmark analysis for post-irAE-PFS but not for post-irAE-OS. A sensitivity analysis using accumulated GCC exposure as the measurement achieved similar results. CONCLUSIONS: Early high-dose GCC use was associated with poorer PFS and OS after irAE onset. Judicious use of GCC early during anti-PD-1 monotherapy should be considered. Further prospective randomized control clinical trials designed to explore alternative irAE management options are warranted.

A Point-of-Care, Real-Time Artificial Intelligence System to Support Clinician Diagnosis of a Wide Range of Skin Diseases.

Dermatological diagnosis remains challenging for nonspecialists because the morphologies of primary skin lesions widely vary from patient to patient. Although previous studies have used artificial intelligence (AI) to classify lesions as benign or malignant, there have not been extensive studies examining the use of AI on identifying and categorizing a primary skin lesion's morphology. In this study, we evaluate the performance of a standalone AI tool to correctly categorize a skin lesion's morphology from a test bank of images. To provide a marker of performance, we evaluate the accuracy of primary care physicians to categorize skin lesion morphology in the same test bank of images without any aids and then with the aid of a simple visual guide. The AI system achieved an accuracy of 68% in determining the single most likely morphology from the test image bank. When the AI's top prediction was broadened to its top three most likely predictions, accuracy improved to 80%. In comparison, the diagnostic accuracy of primary care physicians was 36% without any aids and 68% with the visual guide (P < 0.001). The AI was subsequently tested on an additional set of 222 heterogeneous images of varying Fitzpatrick skin types and achieved an overall accuracy of 70% in the Fitzpatrick I-III skin type group and 68% in the Fitzpatrick IV-VI skin type group (P = 0.79). An AI is a powerful tool to assist physicians in the diagnosis of skin lesions while still requiring the user to critically consider other possible diagnoses.

Antimicrobial efficacy and toxicity of novel CAMPs against P. aeruginosa infection in a murine skin wound infection model.

BACKGROUND: Treatment of P. aeruginosa wound infection is challenging due to its inherent and acquired resistance to many conventional antibiotics. Cationic antimicrobial peptides (CAMPs) with distinct modes of antimicrobial action have been considered as the next-generation therapeutic agents. In the present study, a murine skin surgical wound infection model was used to evaluate the in vivo toxicity and efficacy of two newly designed antimicrobial peptides (CAMP-A and CAMP-B), as chemotherapeutic agents to combat P. aeruginosa infection. RESULTS: In the first trial, topical application of CAMPs on the wounds at a dose equivalent to 4 × MIC for 7 consecutive days did not cause any significant changes in the physical activities, hematologic and plasma biochemical parameters, or histology of systemic organs of the treated mice. Daily treatment of infected wounds with CAMP-A and CAMP-B for 5 days at a dose equivalent to 2× MIC resulted in a significant reduction in wound bacterial burden (CAMP-A: 4.3 log10CFU/g of tissue and CAMP-B: 5.8 log10CFU/g of tissue), compared to that of the mock-treated group (8.1 log10CFU/g of tissue). Treatment with CAMPs significantly promoted wound closure and induced epidermal cell proliferation. Topical application of CAMP-A on wounds completely prevented systemic dissemination of P. aeruginosa while CAMP-B blocked systemic infection in 67% of mice and delayed the onset of systemic infection by at least 2 days in the rest of the mice (33%). In a second trial, daily application of CAMP-A at higher doses (5× MIC and 50× MIC) didn't show any significant toxic effect on mice and the treatments with CAMP-A further reduced wound bacterial burden (5× MIC: 4.5 log10CFU/g of tissue and 50× MIC: 3.8 log10CFU/g of tissue). CONCLUSIONS: The data collectively indicated that CAMPs significantly reduced wound bacterial load, promoted wound healing, and prevented hepatic dissemination. CAMP-A is a promising alternative to commonly used antibiotics to treat P. aeruginosa skin infection.

Beta-defensin derived cationic antimicrobial peptides with potent killing activity against gram negative and gram positive bacteria.

BACKGROUND: Avian ß-defensins (AvBD) are cationic antimicrobial peptides (CAMP) with broad-spectrum antimicrobial activity, chemotactic property, and low host cytotoxicity. However, their bactericidal activity is greatly compromised under physiological salt concentrations which limits the use of these peptides as therapeutic agents. The length and the complex structure involving three conserved disulfide bridges are additional drawbacks associated with high production cost. In the present study, short linear CAMPs (11 to 25 a.a. residues) were developed based on the key functional components of AvBDs with additional modifications. Their biological functions were characterized. RESULTS: CAMP-t1 contained the CCR2 binding domain (N-terminal loop and adjacent α-helix) of AvBD-12 whereas CAMP-t2 comprised the key a.a. residues responsible for the concentrated positive surface charge and hydrophobicity of AvBD-6. Both CAMP-t1 and CAMP-t2 demonstrated strong antimicrobial activity against Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus pseudintermedius. However, CAMP-t1 failed to show chemotactic activity and CAMP-t2, although superior in killing Staphylococcus spp., remained sensitive to salts. Using an integrated design approach, CAMP-t2 was further modified to yield CAMP-A and CAMP-B which possessed the following characteristics: α-helical structure with positively and negatively charged residues aligned on the opposite side of the helix, lack of protease cutting sites, C-terminal poly-Trp tail, N-terminal acetylation, and C-terminal amidation. Both CAMP-A and CAMP-B demonstrated strong antimicrobial activity against multidrug-resistant P. aeruginosa and methicillin-resistant S. pseudintermedius (MRSP) strains. These peptides were resistant to major proteases and fully active at physiological concentrations of NaCl and CaCl2. The peptides were minimally cytotoxic to avian and murine cells and their therapeutic index was moderate (≥ 4.5). CONCLUSIONS: An integrated design approach can be used to develop short and potent antimicrobial peptides, such as CAMP-A and CAMP-B. The advantageous characteristics, including structural simplicity, resistance to salts and proteases, potent antimicrobial activity, rapid membrane attacking mode, and moderate therapeutic index, suggest that CAMP-A and CAMP-B are excellent candidates for development as therapeutic agents against multidrug-resistant P. aeruginosa and methicillin-resistant staphylococci.

Development of a tick-borne pathogen QPCR panel for detection of Anaplasma, Ehrlichia, Rickettsia, and Lyme disease Borrelia in animals.

Anaplasma spp., Ehrlichia spp., Rickettsia spp., and Lyme disease associated Borrelia spp. are the most common tick-borne pathogens reported to infect human beings worldwide and other animals, such as dogs and horses. In the present study, we developed a broad-coverage SYBR Green QPCR panel consisting of four individual assays for the detection and partial differentiation of the aforementioned pathogens. All assays were optimized to the same thermocycling condition and had a detection limit of 10 copies per reaction. The assays remained sensitive when used to test canine and equine blood DNA samples spiked with known amounts of synthetic DNA (gBlock) control template. The assays were specific, as evidenced by lack of cross reaction to non-target gBlock or other pathogens commonly tested in veterinary diagnostic labs. With appropriate Ct cutoff values for positive samples and negative controls and the melting temperature (TM) ranges established in the present study, the QPCR panel is suitable for accurate, convenient and rapid screening and confirmation of tick-borne pathogens in animals.

Novel synthetic analogues of avian ß-defensin-12: the role of charge, hydrophobicity, and disulfide bridges in biological functions.

BACKGROUND: Avian ß-defensins (AvBD) possess broad-spectrum antimicrobial, LPS neutralizing and chemotactic properties. AvBD-12 is a chemoattractant for avian immune cells and mammalian dendritic cells (JAWSII) - a unique feature that is relevant to the applications of AvBDs as chemotherapeutic agents in mammalian hosts. To identify the structural components essential to various biological functions, we have designed and evaluated seven AvBD analogues. RESULTS: In the first group of analogues, the three conserved disulfide bridges were eliminated by replacing cysteines with alanine and serine residues, peptide hydrophobicity and charge were increased by changing negatively charged amino acid residues to hydrophobic (AvBD-12A1) or positively charged residues (AvBD-12A2 and AvBD-12A3). All three analogues in this group showed improved antimicrobial activity, though AvBD-12A3, with a net positive charge of +9, hydrophobicity of 40% and a predicted CCR2 binding domain, was the most potent antimicrobial peptide. AvBD-12A3 also retained more than 50% of wild type chemotactic activity. In the second group of analogues (AvBD-12A4 to AvBD-12A6), one to three disulfide bridges were removed via substitution of cysteines with isosteric amino acids. Their antimicrobial activity was compromised and chemotactic activity abolished. The third type of analogue was a hybrid that had the backbone of AvBD-12 and positively charged amino acid residues AvBD-6. The antimicrobial and chemotactic activities of the hybrid resembled that of AvBD-6 and AvBD-12, respectively. CONCLUSIONS: While the net positive charge and charge distribution have a dominating effect on the antimicrobial potency of AvBDs, the three conserved disulfide bridges are essential to the chemotactic property and the maximum antimicrobial activity. Analogue AvBD-12A3 with a high net positive charge, a moderate degree of hydrophobicity and a CCR2-binding domain can serve as a template for the design of novel antimicrobial peptides with chemotactic property and salt resistance.

Lactobacillus colini sp. nov., isolated from Northern Bobwhite (Colinus virginianus).

Biochemical and molecular studies were performed on five unknown bacterial strains isolated from the intestinal contents of Northern Bobwhites (Colinus virginianus) collected from western Texas, USA. The strains were Gram-stain-positive, catalase-negative, non-spore-forming rods arranged in single cells, pairs or short chains. Colonies on Columbia blood agar are circular, flat, entire, approximately 0.5-1.5 mm in diameter and surrounded with a zone of alpha-haemolysis at after incubation for 48 h at 37 °C. Colonies on MRS agar are umbonate with irregular edge, opaque and approximately 1-1.5 mm in diameter after incubation for 48 h. The 16S rRNA gene sequences of the isolates were identical and the highest sequence similarity (97 %) was found to the type strains of Lactobacillus gasseri, L. johnsonii and L. taiwanensis. The strains were distinguishable from related species of the genus Lactobacilluson the basis of carbohydrate fermentation, enzymatic production and fatty acid profiles. The peptidoglycan type is l-Lys-d-Asp (A4α). The DNA G+C content is 35.6 mol%. Major cellular fatty acids are C14 : 0, C16 : 0 and C18 : 1 ω9c. Based on phenotypic, phylogenetic and chemotaxonomic information, the strains represent a novel species of the genus Lactobacillus for which the name Lactobacillus colini sp. nov. is proposed. The type strain is 111144 L1T (=DSM 101872T=KCTC 21086T).

Structure-function analysis of Avian ß-defensin-6 and ß-defensin-12: role of charge and disulfide bridges.

BACKGROUND: Avian beta-defensins (AvBD) are small, cationic, antimicrobial peptides. The potential application of AvBDs as alternatives to antibiotics has been the subject of interest. However, the mechanisms of action remain to be fully understood. The present study characterized the structure-function relationship of AvBD-6 and AvBD-12, two peptides with different net positive charges, similar hydrophobicity and distinct tissue expression profiles. RESULTS: AvBD-6 was more potent than AvBD-12 against E. coli, S. Typhimurium, and S. aureus as well as clinical isolates of extended spectrum beta lactamase (ESBL)-positive E. coli and K. pneumoniae. AvBD-6 was more effective than AvBD-12 in neutralizing LPS and interacting with bacterial genomic DNA. Increasing bacterial concentration from 10(5) CFU/ml to 10(9) CFU/ml abolished AvBDs' antimicrobial activity. Increasing NaCl concentration significantly inhibited AvBDs' antimicrobial activity, but not the LPS-neutralizing function. Both AvBDs were mildly chemotactic for chicken macrophages and strongly chemotactic for CHO-K1 cells expressing chicken chemokine receptor 2 (CCR2). AvBD-12 at higher concentrations also induced chemotactic migration of murine immature dendritic cells (DCs). Disruption of disulfide bridges abolished AvBDs' chemotactic activity. Neither AvBDs was toxic to CHO-K1, macrophages, or DCs. CONCLUSIONS: AvBDs are potent antimicrobial peptides under low-salt conditions, effective LPS-neutralizing agents, and broad-spectrum chemoattractant peptides. Their antimicrobial activity is positively correlated with the peptides' net positive charges, inversely correlated with NaCl concentration and bacterial concentration, and minimally dependent on intramolecular disulfide bridges. In contrast, their chemotactic property requires the presence of intramolecular disulfide bridges. Data from the present study provide a theoretical basis for the design of AvBD-based therapeutic and immunomodulatory agents.

Failed detection of Bovine viral diarrhea virus 2 subgenotype a (BVDV-2a) by direct fluorescent antibody test on tissue samples due to reduced reactivity of field isolates to raw anti-BVDV antibody.

Bovine viral diarrhea virus 1 (BVDV-1) is associated with mild or subclinical infections, whereas BVDV-2 is frequently implicated in outbreaks of severe thrombocytopenia and acute fatal disease. In the present study, the carcass of a beef breed cow and tissue samples of a beef calf were received for laboratory diagnosis. Both animals exhibited severe clinical signs compatible with thrombocytopenia or hemorrhagic syndrome. Direct fluorescent antibody test (DFAT) failed to detect BVDV antigen in the tissue specimens of both cases. However, immunohistochemistry (IHC) revealed the presence of BVDV antigen in oral and esophageal mucosa and Peyer patches of the beef breed cow. Real-time reverse transcription polymerase chain reaction (real-time RT-PCR) detected BVDV-2 in selected tissues of both animals. Subsequently, BVDV was isolated from both cases and subjected to genetic and serologic characterizations. Mutations in the 5'-untranslated genomic region (5'-UTR) primer and probe binding sites and the E2 gene were associated with reduced efficiency of an established real-time RT-PCR assay and amino acid alterations in the E2 glycoprotein, respectively. Both viral isolates were classified by real-time RT-PCR and phylogenetic analysis as BVDV-2 subgenotype a. Unlike BVDV reference strains Singer and 125c, the isolates cross-reacted with anti-BVDV-1 and anti-BVDV-2 reference sera, indicating antigenic variations in field isolates. The isolates also showed reduced reactivity to porcine anti-BVDV antiserum (the raw serum used to produce BVDV DFA conjugate). In summary, data from the present investigation indicated that genetic and antigenic variations affected the performance of detection assays, especially DFAT, highlighting the need for regular evaluation and modification of BVDV tests.

Diagnosis of Deerpox virus infection in a white-tailed deer (Odocoileus virginianus) fawn.

A 3-month-old fawn from a group of 12 captive white-tailed deer (Odocoileus virginianus) displaying cutaneous lesions was presented to the Mississippi Veterinary Research & Diagnostic Laboratory for necropsy. Postmortem examination identified multiple discrete, round, alopecic, flat, proliferative dermal lesions scattered along the skin of the lips, muzzle, pinna, ventral thorax, medial limbs, and most notably the abdomen. Multiple ulcers were present on the commissures of the lips, dorsal surface of the tongue, and left caudal buccal surface of the oral cavity. The abdomen was filled with fibrinopurulent exudate and ruminal contents. Multiple to coalescing transmural ulcers were identified in the rumen. Histopathological evaluation of the skin revealed markedly thickened epidermis and focal areas of superficial dermal fibrosis, intracytoplasmic, eosinophilic inclusions in swollen keratinocytes and lymphocytic and plasmacytic perivascular dermatitis. The rumen ulcers were surrounded with necrotic cellular debris mixed with fibrin, bacteria, hemorrhages, and a collection of mixed inflammatory cells. Some swollen ruminal mucosal epithelia had eosinophilic intracytoplasmic inclusions. Poxvirus was isolated from the skin and rumen tissue specimens. Electron microscopy detected viral particles with poxvirus morphology. Polymerase chain reaction assays detected A21, a gene conserved within family Poxviridae, in the skin and rumen tissues. Phylogenic analysis of the A21 sequences indicated that the viral isolate (M10-9055) was closely related to known members of genus Cervidpoxvirus. In conclusion, findings indicate that Deerpox virus can produce extensive lesions in white-tailed deer.

An efficient DNA extraction method for polymerase chain reaction-based detection of Mycobacterium avium subspecies paratuberculosis in bovine fecal samples.

Due to the lipid rich cell wall of Mycobacterium avium subspecies paratuberculosis (MAP), the complex nature of bovine feces, and intermittent organism shedding by infected cattle, it is difficult to recover a sufficient amount of high-quality MAP DNA from fecal samples, directly affecting the sensitivity of downstream polymerase chain reaction (PCR) tests. In the current study, a DNA extraction method, designated the Mississippi Veterinary Research and Diagnostic Laboratory (MVRDL) method, was developed for PCR-based detection of MAP in bovine fecal samples. The MVRDL method combined multiple procedures, including chemical pretreatment, 1-tube cell lysis and extraction, chelex matrix absorption, and mini-column purification. The DNA yield and purity, as measured by spectrophotometry, was 3.36 fg per colony forming unit (CFU) MAP and A260/280 absorbance ratio of 2, respectively. This method was further evaluated by real-time PCR. A linear correlation was found between cycle-threshold (Ct) and log input CFU (ranging from 7.2 to 7.2 × 10(7) CFU per ml or CFU per g). The detection limit of the real-time PCR assay was 3 CFU per ml of MAP culture or per g of MAP-spiked feces. In addition, the MVRDL method was validated by performing 7 Johne's direct fecal PCR proficiency tests administered by the National Veterinary Service Laboratories. Based on culture results as the "gold standard," the specificity of MVRDL PCR was 100%, and the sensitivity was 98.46% for samples containing more than 1.5 CFU per tube of fecal cultures. To the authors' knowledge, this is the most efficient MAP DNA extraction method in comparison with all previously published protocols.