Biocompatibility and interaction of porous alumina-zirconia scaffolds with adipose-derived mesenchymal stem cells for bone tissue regeneration

Replacement of bone defects with bone graft or implant is an important therapeutic strategy that has been used in routine practice. However, the identification of biomaterials that can mimic natural bone properties and serve as bone substitutes remains a major challenge. In this context, alumina-zirconia (Al2O3/ZrO2) nanocomposites emerge as potential alternatives for biomedical applications, owing to their high mechanical strength, wear resistance, and biocompatibility. In this sense, in this study, we prepared porous Al2O3/ZrO2 nanocomposites (scaffolds) using the gelcasting method and biomimetically coated them with calcium phosphate (CaP). We evaluated the biocompatibility of the scaffolds using the quantitative MTT cytotoxicity test in L929 cells. Moreover, rabbit adipose-derived mesenchymal stem cells (rADMSCs) were seeded with CaP-containing and CaP-free porous samples to evaluate cell proliferation and cell-scaffold interaction in vitro. Our results showed that the Al2O3/ZrO2 scaffolds were non-cytotoxic, and there were no significant differences between CaP-containing and CaP-free scaffolds in terms of cell growth and adhesion. In contrast, when co-cultured with rADMSCs, the scaffolds enhanced cell proliferation and cell adhesion. The rADMSCs adhered and migrated through the pores of the scaffold and anchored to different poles with differentiated elongated structures. These results suggest osteogenic differentiation of rADMSCs in response to mechanical loading of Al2O3/ZrO2 scaffolds. Therefore, we conclude that Al2O3/ZrO2 scaffolds have demonstrated significant implications in bone tissue engineering and are valuable biomaterials for bone replacement.

Extended reality veterinary medicine case studies for diagnostic veterinary imaging instruction: Assessing student perceptions and examination performance

Educational technologies in veterinary medicine aim to train veterinarians faster and improve clinical outcomes. COVID-19 pandemic, shifted face-to-face teaching to online, thus, the need to provide effective education remotely was exacerbated. Among recent technology advances for veterinary medical education, extended reality (XR) is a promising teaching tool. This study aimed to develop a case resolution approach for radiographic anatomy studies using XR technology and assess students' achievement of differential diagnostic skills. Learning objectives based on Bloom's taxonomy keywords were used to develop four clinical cases (3 dogs/1 cat) of spinal injuries utilizing CT scans and XR models and presented to 22 third-year veterinary medicine students. Quantitative assessment (ASMT) of 7 questions probing 'memorization', 'understanding and application', 'analysis' and 'evaluation' was given before and after contact with XR technology as well as qualitative feedback via a survey. Mean ASMT scores increased during case resolution (pre 51.6% (±37%)/post 60.1% (± 34%); p < 0.01), but without significant difference between cases (Kruskal-Wallis H = 2.18, NS). Learning objectives were examined for six questions (Q1-Q6) across cases (C1-4): Memorization improved sequentially (Q1, 2 8/8), while Understanding and Application (Q3,4) showed the greatest improvement (26.7%-76.9%). Evaluation and Analysis (Q5,6) was somewhat mixed, improving (5/8), no change (3/8) and declining (1/8).Positive student perceptions suggest that case studies' online delivery was well received stimulating learning in diagnostic imaging and anatomy while developing visual-spatial skills that aid understanding cross-sectional images. Therefore, XR technology could be a useful approach to complement radiological instruction in veterinary medicine.

Cardiopulmonary and propofol-sparing effects of dexmedetomidine in total intravenous anesthesia in cats undergoing ovariohysterectomy

OBJECTIVES

This study aimed to assess the effect of dexmedetomidine on the propofol-based anesthesia of cats subjected to ovariohysterectomy.

METHODS

Twenty-eight cats were randomly allocated to four groups (seven cats in each) and premedicated with either 5 µg/kg dexmedetomidine (groups Dex 1, Dex 3 and Dex 5) or 0.05 ml saline (Prop group) intramuscularly. After the induction of anesthesia with propofol, total intravenous anesthesia was initiated with 300 µg/kg/min propofol plus 3 ml/kg/h NaCl 0.9% (Prop), or 200 µg/kg/min propofol plus dexmedetomidine at the rates of 1 µg/kg/h (Dex 1), 3 µg/kg/h (Dex 3) or 5 µg/kg/h (Dex 5). Cardiorespiratory variables were assessed 5 mins after induction and every 10 mins thereafter, until the end of anesthesia. The propofol infusion rate was adjusted every 10 mins (± 50 µg/kg/min) to maintain anesthetic depth. The times to extubation, sternal recumbency, ambulation and total recovery were recorded. Pain scoring was performed 1, 2, 4, 8, 12 and 24 h after the end of anesthesia.

RESULTS

Dexmedetomidine produced a propofol-sparing effect of 72.8%, 71.1% and 74.6% in the Dex 1, Dex 3 and Dex 5 groups, respectively. Cats in the Prop group maintained higher heart rate values than the other groups, and the mean arterial pressure remained higher in the Dex 3 and Dex 5 groups. Rescue intraoperative analgesia (fentanyl bolus) was most frequent in the Prop group. There was no significant difference in the time of extubation. Cats in the Dex 1 and Dex 3 groups had a faster anesthetic recovery, with shorter times to achieving sternal recumbency, regaining ambulation and reaching full recovery. Cats in the Dex 1 and Dex 5 groups presented the best recovery quality scores, with 4 (range 4-5) and 4 (range 3-5), respectively, while the Prop group scored 1 (range 1-3), the worst anesthetic recovery score among the groups.

CONCLUSIONS AND RELEVANCE

The use of dexmedetomidine as a total intravenous anesthesia adjuvant, especially at doses of 1 and 3 µg/kg/h, reduces propofol consumption and improves cardiorespiratory stability and intraoperative analgesia, while promoting a better and quicker recovery from anesthesia.

Correlation Between Peritonitis and Incisional Infections in Horses

Surgical site infection of abdominal incisions is an important complication after laparotomy with increased risk of incisional hernia formation in horses. This study aims to evaluate the healing process of abdominal incisions and correlate peritonitis with the occurrence of surgical site infection and incisional hernias. Nine horses underwent standardized laparotomy, intestinal exploration, and induced septic peritonitis. Standardized relaparotomy was performed two (n = 3), four (n = 3), and six (n = 3) months later to evaluate the abdominal cavity for adhesions and to collect the sutured ventral abdominal wall to evaluate and prepare it for histopathological and tensile strength study. All horses presented with endotoxemia, controllable peritonitis, heat and touch-sensitive ventral abdominal edema and surgical wound infection with presence of purulent discharge. Adhesion of the cecum or colon to the internal portion of the surgical wound was observed. Healing of the infected surgical wounds occurred by second intention and a space between the rectus abdominis muscles developed because of the presence of a scar, which was related to incisional hernia. In the histopathological evaluation, the collagen content increased, and the inflammation decreased over time. The tensile strength increased over time and was highest after 6 months. After the second surgical intervention, there was no infection of the surgical wound in any of the animals and healing by first intention occurred. Surgical site infection may be a symptom of peritonitis in horses recovering from abdominal surgery. Infected surgical wounds heal by second intention, which favors the spacing of rectus abdominis muscle and the formation of incisional hernia.

Abstract 819: Transcriptomic profiling of two canine mammary cancer cell lines for translational oncology studies

Dogs develop spontaneous cancers as humans and shares a variety of features including histology, genomic alterations, molecular targets, biological behavior and response to conventional therapies. Although dogs can be considered good models for translation of new cancer treatments, there is a lack of established preclinical in vitro models of canine cancers. Therefore, our aim here was to establish two canine mammary cancer cell lines and characterize their transcriptomic profile to speed the translation of new cancer treatments from dogs to humans. Mammary cancer samples were obtained from female dogs that underwent surgery. Pieces of the tumors were FFPE for histopathology and the other fragments were washed with PBS, minced and dissociated with hyaluronidase and collagenase. Cells were filtered and put in culture with DMEM-F12, 5%FBS and 1% pen-strep. After 5 passages, FBS was increased to 10%. After passage 15, cells were characterized for doubling time, karyotype, immunocytochemistry for cytokeratin, vimentin and α-smooth muscle actin, matrigel-invasion assay and tumor growth in nude mice. At last, RNA-seq was performed on total RNA extracted with TRIZOL for functional enrichment analysis of differentially expressed (DE) genes from cancer cell lines. From 49 tumor samples, we characterized 2 cell lines named M5 and M25, originally from a comedocarcinoma and a mixed carcinoma, respectively. Both cell cultures showed spindle-shape cells and were positive for cytokeratin, vimentin and α-smooth actin, suggesting myoepithelial origin. The doubling time was 26.0h for M5 and 42.8h for M25 cells. Karyotyping analysis showed moderate aneuploidy for both cell cultures. M25 cell line presented significant higher invasion potential than M5 cells and formed tumors in mice but the latter didn’t. Histopathology of these tumors resembled the original tumor in the dog. An average of 16.2 million paired-end 100 bp reads were sequenced per replicate (three for each cell culture) with an average of 81.1% alignment to the reference genome. A total of 11,260 and 11,476 genes with more than 1 count per million were detected in M5 and M25 cell lines. M5 cell line have 404 and 394 up- and downregulated genes in comparison to M25 cell line, respectively. Gene ontology of DE genes showed the more malignant cell (M25) significantly enriched for pathways related to drug metabolism, ECM-receptor interaction, cell cycle, DNA replication, focal adhesion and cell differentiation. In conclusion, M25 cell line is more malignant than the M5 which is supported by their transcriptome. Thus, it is possible to use these cells as a comparative translational model for drug development especially if one wishes to work with molecular targets as described above.

Citation Format: Heidge Fukumasu, Yonara G. Cordeiro, Pedro L. Xavier, Arina L. Rochetti, Pamela A. Alexandre, Claudia C. Mori, Silvio H. Freitas, Ricardo F. Strefezzi. Transcriptomic profiling of two canine mammary cancer cell lines for translational oncology studies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 819. doi:10.1158/1538-7445.AM2017-819

Estudo epidemiológico e avaliação de fatores de risco da infecção por Toxoplasma gondii e achados clinico-patológicos da infecção aguda em cães admitidos em um Hospital Escola Veterinário

RESUMO: Esse trabalho teve como objetivo estudar a prevalência e respectivos fatores de risco para infecção do Toxoplasma gondii em cães provenientes de uma população hospitalar. Além disso, avaliou-se as taxas de ocorrência e as repercussões clínico-patológicas da infecção aguda pelo T. gondii nesses animais. Anticorpos foram detectados em 7% (26/386) da população estudada, composta de 386 cães de ambos os sexos e diferentes raças e idades. Somente as variáveis, ingestão de vísceras, origem rural e contato com bovinos apresentaram valores significativos com p<0.05. Adicionalmente os cães de origem rural apresentaram maiores risco (OD=7.00) de infecção do que aqueles de origem urbana. Em 6,5% (25/386) foram detectados títulos de contato (entre 16 e 256); esses títulos não significam necessariamente infecção aguda e sim apenas exposição prévia. É de fundamental importância o reconhecimento da infecção prévia por T. gondii nesses pacientes hospitalares. Dependendo da causa da admissão, mesmo não sendo a toxoplasmose a responsável, o paciente deve receber o tratamento anti-protozoário profilaticamente ou ser monitorado para posterior tratamento em caso de reagudização da enfermidade por recrudescência dos bradizoítos encistados. Apenas um animal (3.44%, 1/386) foi admitido com titulação elevada, o qual pode ser sugestivo de infecção aguda (titulo de 4096). Embora o animal com infecção aguda tenha sido apresentado com sinais neurológicos, cautela é necessária para não extrapolar uma falsa interpretação que a toxoplasmose é a grande responsável por quadros neurológico, uma vez que inúmeros outros casos incluídos nesse estudo tinham manifestações neurológicas e não tinham títulos de infecção aguda, nem mesmo título de contato prévio. A toxoplasmose aguda não foi uma afecção clínica expressiva nessa ambiência hospitalar, no entanto diagnóstico diferencial deve ser feito nos pacientes enfermos, principalmente os da área rural, e diagnostico definitivo deve ser alcançado para a correta conduta terapêutica.

Investigação clínica e comparação do esfregaço sanguíneo e PCR para diagnóstico de hemoparasitas em equinos de esporte e tração (carroceiros)

Resumo: Na clínica médica de equinos, explora-se o perfil hematológico do animal, geralmente, com a finalidade de encontrar alterações que não foram constatadas ao exame clínico. A pesquisa de hematozoários em equinos, muitas vezes, apresenta resultados conflitantes entre o quadro clínico apresentado pelo animal e o resultado laboratorial, levantando a hipótese de que a técnica de pesquisa de hematozoários seja a responsável por falhas diagnósticas. Este estudo visa comparar os valores obtidos em exames hematológicos de 15 equinos de esporte e 15 equinos de tração (carroceiros), levando-se em consideração diferenças como características nutricionais, estado de higidez e tipo de atividade realizada, e comparar as diferentes técnicas de pesquisa de hematozoários, como esfregaço sanguíneo e PCR. Verificou-se que apenas os equinos de tração apresentaram valores médios de hemácias, hematócrito e hemoglobina abaixo do considerado fisiológico para a espécie, embora 100% dos animais, de ambos os grupos experimentais, tenham sido considerados positivos para hemoparasitoses por PCR. Verifica-se a superioridade do método de pesquisa de hemoparasitas por PCR, em comparação com esfregaço sanguíneo, realizado por diferentes técnicas, visto que apenas 33,3% dos animais foram considerados positivos para Theileria equi por esta técnica, enquanto que o PCR revelou 100% de positividade, para Theileria equi, Babesia caballi e infecção mista. Nenhum dos animais estudados foi diagnosticado com Anaplasma phagocytophilum (Ehrlichia equi) e Ehrlichia risticcii (Neoricketsia risticii). Verifica-se, então, que muitos dos diagnósticos de ausência de hemoparasitose por exame hematológico e ou esfregaço sanguíneo são errôneos, devido à baixa sensibilidade da técnica e podem repercutir em falha no tratamento ou disseminação dos hemoparasitos e das hemoparasitoses. Ressalta-se, então, a importância de exames como o PCR na elaboração de diagnóstico definitivo.

Evaluation of intravenous regional perfusion with amphotericin B and dimethylsulfoxide to treat horses for pythiosis of a limb

BACKGROUND

Treatment for horses with pythiosis of a limb is challenging. This study aims to evaluate the effects of administering amphotericin B in a 10 % solution of dimethylsulfoxide by intravenous regional limb perfusion (IRLP) to treat horses for cutaneous pythiosis of a limb.

RESULTS

All 15 of the horses treated had complete resolutions of their lesion between 6 to 9 weeks after a single IRLP treatment. No complications were observed at the site of venipuncture for IRLP. Before initiation of treatment, there was anemia and marked leucocytosis which resolved following treatment. Serum biochemistry showed no significant changes.

CONCLUSIONS

IRLP administration of amphotericin B in a 10 % DMSO solution was easily performed, relatively inexpensive and an effective treatment for treating horses for pythiosis of a limb and resolved the infection with no complications.

Aspecto radiológico e macroscópico de matriz óssea mineralizada heteróloga fragmentada e polimetilmetacrilato autoclavados em falha óssea de tíbia de coelho

Foi realizada falha segmentar com 6mm de diâmetro na região metafisária medial de tíbias de 12 coelhos, onde foi implantado uma associação de micro e macrofragmentos de matriz óssea cortical heteróloga fragmentada conservada em glicerina (98%) e polimetilmetacrilato autoclavados, para a sua reconstrução, e avaliados radiológica e macroscopicamente aos 30, 60, 90 e 120 dias. Houve adesão, em relação ao tempo, dos micro e macrocompósitos ao leito receptor, em 100% dos casos, mostrando ser biologicamente biocompatível, pois promoveram a reparação de falhas ósseas, sem sinais de infecção, migração e/ou rejeição, podendo, dessa forma, ser mais uma opção como substituto para preencher grandes defeitos ósseos.