Beagle Research Articles

Prediction of apparent total tract digestion of crude protein in adult dogs.

To predict the apparent total tract digestibility (ATTD) of crude protein (CP) in dogs we developed an in vitro system using an in vitro digestion method and a statistical analysis. The experimental diets used chicken meat powder as the protein source, with CP levels of 20% (22.01%, analyzed CP value as dry-based), 30% (31.35%, analyzed CP value as dry-based), and 40% (41.34%, analyzed CP value as dry-based). To simulate in vivo digestive processes a static in vitro digestion was performed in two steps; stomach and small intestine. To analyze ATTD the total fecal samples were collected in eight neutered beagle dogs during the experimental period. CP digestibility was calculated by measuring CP levels in dog food, in vitro undigested fraction, and dog feces. In result, CP digestibility at both in vivo and in vitro was increased with increasing dietary CP levels. To estimate in vivo digestibility the co-relation of in vivo ATTD and in vitro digestibility was investigated statistically and a regression equation was developed to predict the CP ATTD (% = 2.5405 × in vitro CP digestibility (%) + 151.8). The regression equation was evaluated its feasibility by using a commercial diet. The predicted CP digestibility which was calculated by the regression equation showed high index of similarity (100.16%) with that of in vivo in dogs. With that, it would be a feasible non-animal method to predict in vivo CP digestibility by using in vitro digestion method and the proposed linear regression equation in adult dogs.

Immunophenotyping of canine T cell activation and proliferation by combined protein and RNA flow cytometry

The limited availability of canine-reactive monoclonal antibodies restricts the analyses of immune cell subsets and their functions by flow cytometry. The PrimeFlow™ RNA Assay may serve as a potential solution to close this gap. Here we report a blood immunophenotyping method utilizing combined protein- and RNA-based flow cytometry to characterize canine T cell activation and proliferation within individual cells. In this assay, CD69 expression was detected by an RNA probe and CD25 and Ki67 were detected by antibodies. Canine peripheral blood mononuclear cells (PBMCs) were stimulated with three agents with different modes of action, anti-CD3/CD28 antibodies, phytohemagglutinin, or phorbol myristate acetate /ionomycin. Robust T cell activation (CD25+ and/or CD69+) and proliferation (Ki67+) were detected. Both CD69 and CD25 appear to be robust and sensitive T cell activation markers with early induction and low background expression. Upon stimulation, T cell proliferation occurred later than T cell activation and was associated with CD25 expression. This canine T cell activation and proliferation immunophenotyping method was evaluated in 5 independent experiments using PBMCs from 10 different beagle dogs with satisfactory assay performance. This method can greatly facilitate the evaluation of immune disease pathogenesis and immunotoxicity risk assessment in nonclinical drug development in canine.

Comprehensive characterization of the effect of mineralocorticoid receptor antagonism with spironolactone on the renin-angiotensin-aldosterone system in healthy dogs.

To characterize the dose-exposure-response effect of spironolactone on biomarkers of the classical and alternative arms of the renin-angiotensin-aldosterone system (RAAS) in healthy dogs. Ten healthy purpose-bred Beagle dogs. Study dogs were randomly allocated to 2 spironolactone dosing groups (2 mg/kg PO q24hr, 4 mg/kg PO q24hr). The dogs received 7-day courses of spironolactone followed by a 14-day washout period in a crossover (AB/BA) design. Angiotensin peptides and aldosterone were measured in serum using equilibrium analysis, and plasma canrenone and 7-α-thiomethyl spironolactone (TMS) were quantified via liquid chromatography-mass spectrometry/mass spectroscopy (LC-MS/MS). Study results were compared before and after dosing and between groups. Following spironolactone treatment, dogs had a significant increase in serum aldosterone concentration (P = 0.07), with no statistical differences between dosing groups. Significant increases in angiotensin II (P = 0.09), angiotensin I (P = 0.08), angiotensin 1-5 (P = 0.08), and a surrogate marker for plasma renin activity (P = 0.06) were detected compared to baseline following spironolactone treatment during the second treatment period only. Overall, changes from baseline did not significantly differ between spironolactone dosages. RAAS analytes were weakly correlated (R < 0.4) with spironolactone dosage and plasma canrenone or plasma TMS. There were no adverse clinical or biochemical effects seen at any spironolactone dosage during treatment. Treatment with spironolactone increased serum aldosterone concentration in healthy dogs and impacted other biomarkers of the classical and alternative arms of the RAAS. There was no difference in effect on the RAAS between 2 and 4 mg/kg/day dosing. Dosage of 4 mg/kg/day was safe and well-tolerated in healthy dogs.

INSL3 Variation in Dogs Following Suppression and Recovery of the HPG Axis.

Insulin-like peptide 3 (INSL3) is a constitutive product of mature, adult-type Leydig cells of the testes and consequently in most mammals is an ideal biomarker with which to monitor pubertal development. A new heterologous time-resolved fluorescence immunoassay was developed and validated to measure circulating INSL3 in the blood of adult male dogs. Compared to other species, INSL3 concentration is low with marked variation between individuals, which appears to be independent of breed, age, or weight. A model system was then used in which a cohort of beagle dogs was subject to a GnRH-agonist implant to suppress the HPG axis and spermatogenesis, followed by implant removal and recovery. Unlike testosterone, INSL3 levels were not fully suppressed in all animals by the GnRH agonist, nor was the recovery of Leydig cell function following implant removal uniform or complete, even after several weeks. In dogs, and dissimilar from other species (including humans), Leydig-cell INSL3 appears to be quite variable between individual dogs and only weakly connected to the physiology of the HPG axis after its suppression by a GnRH-agonist implant and recovery. Consequently, INSL3 may be less useful in this species for the assessment of testis function.

Squid meal and shrimp hydrolysate as novel protein sources for dog food.

The world's growing pet population is raising sustainability and environmental concerns for the petfood industry. Protein-rich marine by-products might contribute to mitigating negative environmental effects, decreasing waste, and improving economic efficiency. The present study evaluated two marine by-products, squid meal and shrimp hydrolysate, as novel protein sources for dog feeding. Along with the analysis of chemical composition and antioxidant activity, palatability was evaluated by comparing a commercial diet (basal diet) and diets with the inclusion of 150 g kg-1 of squid meal or shrimp hydrolysate using 12 Beagle dogs (2.2 ± 0.03 years). Two in vivo digestibility trials were conducted with six dogs, three experimental periods (10 days each) and three dietary inclusion levels (50, 100 and 150 g kg-1) of squid meal or shrimp hydrolysate in place of the basal diet to evaluate effects of inclusion level on apparent total tract digestibility (ATTD), metabolizable energy content, fecal characteristics, metabolites, and microbiota. Both protein sources presented higher protein and methionine contents than ingredients traditionally used in dog food formulation. Shrimp hydrolysate showed higher antioxidant activity than squid meal. First approach and taste were not affected by the inclusion of protein sources, but animals showed a preference for the basal diet. Effects on nutrient intake reflected the chemical composition of diets, and fecal output and characteristics were not affected by the increasing inclusion levels of both protein sources. The higher ATTD of dry matter, most nutrients and energy of diets with the inclusion of both by-products when compared to the basal diet, suggests their potential to be included in highly digestible diets for dogs. Although not affected by the inclusion level of protein sources, when compared to the basal diet, the inclusion of squid meal decreased butyrate concentration and shrimp hydrolysate increased all volatile fatty acids, except butyrate. Fecal microbiota was not affected by squid meal inclusion, whereas inclusion levels of shrimp hydrolysate significantly affected abundances of Oscillosperaceae (UCG-005), Firmicutes and Lactobacillus. Overall, results suggest that squid meal and shrimp hydrolysate constitute novel and promising protein sources for dog food, but further research is needed to fully evaluate their functional value.

Determining the effects of Candida utilis-fermented pea starch vs. unfermented pea starch, alone or in whole diets, on palatability and glycemic response in dogs and cats.

Current research suggests yeast fermentation has the potential to improve palatability of pea-based diets for both cats and dogs. However, to be useful, fermentation should not compromise other healthy attributes of peas such as a low glycemic response. Fermentation of uncooked pea starch with Candida utilis (ATCC 9950) appeared to increase crude protein, crude fiber content, inorganic compounds (phosphorus and iron) and phenols. Whole diets were designed with fermented and unfermented pea starch to assess palatability, food intake, and glycemic responses in unacclimated, mixed sex Beagle dogs and mixed breed cats (n = 8 and n = 7, respectively). For palatability testing, a control diet was formulated with 30% corn starch as well as test diets with 30% inclusion of fermented or unfermented pea starch (all lab-made), then compared to a commercial diet containing pea starch (Legacy/Horizon). Fermentation had little effect on rapidly digestible starch either in uncooked starch form or when incorporated into whole diets, but did decrease resistant starch by 15% and increase slowly digestible starch by 20%. Palatability tests using either two choices or four choices at a time revealed a significant preference for the fermented pea starch diet (p < 0.01) in both species. For the glycemic responses, a total of four different pea products were included: unfermented pea starch, fermented pea starch, and 30% inclusion of unfermented and fermented pea starch in whole formulated diets. There were no significant changes in glycemic responses with the fermented pea diet compared to the unfermented diet, demonstrating that healthful low glycemic properties of pea starch were retained after C. utilis fermentation. Overall, C. utilis-fermentation technique was successfully adapted to pea starch where it resulted in increased palatability and food intake in dogs and cats, with potential to positively contribute to overall health benefits for both species.

Cardiopulmonary and recovery effect of intravenous caffeine in anesthetized Beagle dogs

Cardiopulmonary and recovery effect of intravenous caffeine in anesthetized Beagle dogs

Inflammatory Reprogramming Mediates Changes in Three-Dimensional Strain Capacity and Cardiac Function in Beagle Dogs with Doxorubicin-Related Cardiomyopathy.

The cardiotoxicity of doxorubicin (DOX) limits its use in cancer treatment. To address this limitation, we developed a novel animal model that uses beagle dogs to investigate DOX-induced cardiac disorders. Unfortunately, the lack of effective cardioprotection strategies against DOX-induced cardiotoxicity poses a significant challenge. To establish a canine model for low-mortality DOX-induced cardiac dysfunction and explore the relationship between inflammatory reprogramming and DOX-related cardiotoxicity. Twenty male beagle dogs aged two years were randomly assigned into the DOX (N = 10) and control (CON) (N = 10) groups. DOX was infused (1.5 mg/kg) every two weeks until doses cumulatively reached 12 mg/kg. Serum biomarkers and myocardial pathology were evaluated, while real-time fluorescence-based quantitative polymerase chain reaction (RTFQ-PCR), two- and three-dimensional echocardiography (2DE and RT3DE), functional enrichment, and matrix correlation were also performed. In the DOX group, high-sensitive cardiac troponin T (hs cTnT) and N-terminal pro-brain natriuretic peptide (NT-proBNP) were significantly increased. Myocardial pathology indicated early to medium myocardial degeneration via a decreased cardiomyocyte cross-sectional area (CSA). Increased levels of inflammatory gene transcripts (interleukin 6 (IL6), tumor necrosis factor (TNF), transforming growth factor (TGF ), intercellular adhesion molecule 1 (ICAM1), interleukin 1 (IL1), interleukin 1 (IL1 ), and interleukin 8 (IL8)), of collagen metabolism and deposition regulatory genes (matrix metalloproteinase (MMP) family and tissue inhibitor of matrix metalloproteinase (TIMP) family), and the natriuretic peptide family (NPS) (natriuretic peptide A, B and C (NPPA, NPPB, and NPPC)) were observed. Strain abnormalities in the right ventricular longitudinal septal strain (RVLSS), right ventricular longitudinal free-wall strain (RVLFS), left ventricular global longitudinal strain (LVGLS), and left ventricular global circumferential strain (LVGCS) were detected at week 28 (vs. week 0 or CON group, p 0.05, respectively). A significant decline in RVLSS and RVLFS occurred at week 16, which was earlier than in the corresponding left ventricular areas. A significant right ventricular ejection fraction (RVEF) decline was noted at week 16 (vs. week 0, 33.92 3.59% vs. 38.58 3.58%, p 0.05), which was 12 weeks earlier than for the left ventricular ejection fraction (LVEF), which occurred at week 28 (vs. week 0, 49.02 2.07% vs. 54.26 4.38%, p 0.01). The right ventricular strain and functional damages correlated stronger with inflammatory reprogramming (most R from 0.60 to 0.90) than the left ones (most R from 0.30 to 0.65), thereby indicating a more pronounced correlation. Inflammatory reprogramming mediated disorders of strain capacity and cardiac function predominantly in the right side of the heart in the newly established DOX-related cardiomyopathy beagle dog model.

Octacalcium phosphate collagen composite for periodontal regeneration in a canine one-wall intrabony defect.

This study aimed to evaluate the regenerative capacities of octacalcium phosphate collagen composite (OCP/Col) in one-wall intrabony defects in dogs. The background data discuss the present state of the field: No study has assessed the efficacy of OCP/Col for periodontal regeneration therapy despite the fact that OCP/Col has proved to be efficient for bone regeneration. In six beagle dogs, the mandibular left third premolars were extracted 12 weeks before the experimental surgery. Standardized bone defects (5 mm in height and 4 mm in width) were simulated on the distal surface of the second premolars and mesially on the fourth premolars. The defect was filled with either OCP/Col (experimental group) or left empty (control group). Histological and histomorphometric characteristics were compared 8 weeks after surgery. No infectious or ankylotic complications were detected at any of the tested sites. The experimental group exhibited a significantly greater volume, height, and area of newly formed bone than the control group. The former also showed a greater height of the newly formed cementum than the latter, although the results were not statistically significant. The newly formed periodontal ligaments were inserted into newly formed bone and cementum in the experimental group. OCP/Col demonstrated high efficacy for bone and periodontal tissue regeneration that can be successfully applied for one-wall intrabony defects.

Anaesthetic-sparing effect of the anxiolytic drug tasipimidine in Beagle dogs

ObjectiveTo evaluate the effect of oral tasipimidine on dog handling, ease of catheter placement and propofol and isoflurane requirements for anaesthesia. Study designPlacebo-controlled, randomized, blinded, experimental trial. AnimalsA group of seven adult Beagle dogs weighing (mean ± standard deviation) 13.1 ± 2.7 kg with a mean age of 18.6 ± 1 months. MethodsThe dogs underwent four treatments before induction of anaesthesia with propofol. PP: placebo orally (PO) 60 minutes before induction of anaesthesia followed by placebo (NaCl 0.9%) intravenously (IV). TP: tasipimidine 30 μg kg–1 (PO) 60 minutes before induction of anaesthesia followed by placebo (NaCl 0.9%) IV. TMP: tasipimidine 30 μg kg–1 PO 60 minutes before induction of anaesthesia followed by methadone 0.2 mg kg–1 IV. TMPD: tasipimidine 30 μg kg–1 PO 60 minutes before induction of anaesthesia followed by methadone 0.2 mg kg–1 and dexmedetomidine 1 μg kg–1 IV followed by a dexmedetomidine constant rate infusion of 1 μg kg–1 hour–1.Sedation, response to catheter placement, intubation quality, time to loss of consciousness, time to intubation, required dose of propofol and minimum alveolar isoflurane concentration preventing motor movement (MACNM) were determined.A mixed-model analysis or the Friedman and Mann–Whitney test were used; p-value < 0.05. ResultsResponse to catheter placement did not differ between treatments. Tasipimidine alone reduced the propofol dose by 30%. Addition of methadone or methadone and dexmedetomidine reduced the propofol dose by 48% and 50%, respectively. Isoflurane MACNM was reduced by 19% in tasipimidine-medicated dogs, whereas in combination with methadone or methadone and dexmedetomidine, isoflurane MACNM was reduced by 35%. Conclusions and clinical relevanceAn anxiolytic dose of tasipimidine induced mild signs of sedation in dogs and reduced propofol and isoflurane requirements to induce and maintain anaesthesia, which needs to be considered in an anaesthetic plan.

3Y-TZP/Ta Biocermet as a Dental Material: An Analysis of the In Vitro Adherence of Streptococcus Oralis Biofilm and an In Vivo Pilot Study in Dogs.

The surface adhesion of bacterial cells and the in vivo biocompatibility of a new ceramic-metal composite made of zirconium dioxide and tantalum were evaluated. Within the framework of an in vitro study using the crystal violet staining and colony counting methods, a relatively similar adhesion of Streptococcus oralis to the 3Y-TZP/Ta biocermet (roughness Ra = 0.12 ± 0.04 µm) and Ti-Al6-V4 titanium alloy (Ra = 0.04 ± 0.01 µm) was found. In addition, in an in vivo preliminary study focused on the histological analysis of a series of rods implanted in the jaws of beagle dogs for a six-month period, the absence of any fibrous tissue or inflammatory reaction at the interface between the implanted 3Y-TZP/Ta biocermets and the new bone was found. Thus, it can be concluded that the developed ceramic-metal biocomposite may be a promising new material for use in dentistry.

Persistence of clock gene expression in peripheral blood in dogs maintained under different photoperiod schedules

ABSTRACT Dogs are the common pets adopted by humans, and their circadian behavior and physiology are influenced by human habits. In many families, there is a change of lifestyle with respect to the natural daylight (NDL) cycle. Exposure to constant light disrupts some central and peripheral circadian rhythms. The aim of the present study was to improve the knowledge about the circadian changes of clock components in the peripheral blood in dogs housed under NDL and constant light (LL) conditions. Blood samples were collected on five female Beagle dogs (2 years old, 14 ± 0.5 kg) every 4 hours for a 24-hour period during an NDL (Sunrise 05:05 h – Sunset 20:55 h) and 24-hour period of constant light (LL). Blood samples were stored in a PAX gene Blood RNA Tube, real-time RT-quantitative polymerase chain reaction was performed to determine Clock, Per1–3, and Cry1–2 gene expression. During the NDL, all genes investigated showed robust diurnal daily rhythmicity. During the constant light, only Clock maintained its daily rhythmicity. Clock acrophase was observed close to sunrise (ZT 0) and was statistically different from the other clock genes except for Per3. Per3 daily oscillations were not statistically significant. No differences were observed among the clock genes tested in the amplitude and robustness values. Our results can be considered preliminary data to provide new insights into the adaptation mechanism of the canine peripheral circadian clock. The persistence of Clock gene expression during the LL indicated the presence of an endogenously generated signal in blood. Because peripheral blood is an easily accessible sample in dogs, the analysis of clock gene expression in this tissue could be useful to investigate the adaptive capacity of this species housed in different environmental conditions linked to the owner’s lifestyle.

Herb-drug interactions of silybinin and cilofexor in beagle dogs based on pharmacokinetics by UPLC-MS/MS.

Objective: A remarkably sensitive, accurate, and efficient ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) approach was developed as a facile and expeditious method for measuring cilofexor concentration in beagle dogs, the herb-drug interactions between silybinin and cilofexor was explored based on pharmacokinetics. Methods: The plasma sample protein of the beagles were rapidly sedimented with acetonitrile, and cilofexor and tropifexor (internal standard, ISTD) were separated by gradient elution using a 0.1% formic acid aqueous solution and acetonitrile as the mobile phase. The concentrations were detected using positive ion multiple reaction monitoring (MRM) mode. Mass transfer pairs were m/z 587.91→267.91 for cilofexor and m/z 604.08→228.03 for ISTD, respectively. A two-period self-controlled experimental design was adopted for the HDIs experiment. In the first period (Group A), six beagle dogs were orally administered cilofexor at a dose of 1mg/kg. In the second period (Group B), silybinin (3mg/kg) was orally administered to the six beagle dogs twice a day for seven consecutive days, after which cilofexor was orally administered. The cilofexor concentration in beagle dogs was determined, and HDIs were evaluated based on their pharmacokinetics. Results: The accuracy and precision of cilofexor were both less than 15%, and the recoveries, matrix effects, and stability met the relevant requirements. The Cmax of cilofexor in group B was 49.62% higher than that in group A, whereas the AUC(0-t) and AUC(0-∞) of cilofexor in group B were 47.85% and 48.52% higher, respectively, than those in group A. Meanwhile, the t1/2 extended from 7.84h to 9.45 h, CL and Vz decreased in Group B. Conclusion: A novel UPLC-MS/MS approach was successfully applied for the measurement of cilofexor in beagle dog plasma. Silybinin can alter the pharmacokinetics of cilofexor in beagle dogs, thereby increasing plasma exposure to cilofexor.

Establishment of a spontaneous ventilation anesthesia model for beagle dogs

While spontaneous ventilation (SV) anesthesia is in use for clinical patients, there is still little systematic experimental research into its basic aspects. The rabbit SV model that we established previously has some limitations including the model being too small, differences in anesthetic drugs and anesthesia procedures, so we set out to establish an SV anesthesia model for beagle dogs.•Single lumen tracheal intubation was performed on beagles connecting a ventilator, and the anesthetic dosage was adjusted for spontaneous ventilation before surgery.•5 mL of 1 % lidocaine was applied as a local infiltration anesthesia at the surgical incision.•After thoracotomy, 5 mL of 1% lidocaine was sprayed onto the surface of the lungs and a T3–T7 intercostal nerve block (1:1 2 % lidocaine:0.75 % ropivacaine) was performed.

Neck pain and tetraparesis in a 9-year-old Beagle dog.

Neck pain and tetraparesis in a 9-year-old Beagle dog.

Primary hyperparathyroidism and concurrent severe hypergastrinemia in a dog

AbstractA 7‐year‐old, neutered, male beagle dog was presented for the investigation of hyporexia, vomiting and polyuria‐polydipsia. Ionised hypercalcaemia secondary to primary hyperparathyroidism was diagnosed. The dog developed a perforated gastric ulcer associated with marked hypergastrinemia. The dog died of cardiopulmonary arrest 6 days after admission. Gastrinoma can be associated with Zollinger–Ellison syndrome, characterised by the presence of peptic ulcers and hypergastrinemia. Concurrent primary hyperparathyroidism and gastrinoma is a typical presentation of multiple endocrine neoplasia type 1 syndrome, a human syndrome that causes the development of several tumours in endocrine glands; but has never been described in dogs. Hypergastrinemia secondary to hypercalcaemia, and unrelated to gastrinoma, has also been described in humans, but not in dogs. This case reports the atypical co‐occurrence of primary hyperparathyroidism and severe hypergastrinemia, which could be a consequence of hypercalcaemia, or be secondary to a concurrent disease such as an undetected gastrinoma.

Effects of orally administered crofelemer on the incidence and severity of neratinib-induced diarrhea in female dogs.

Targeted therapies have increased cancer therapy-related diarrhea (CTD) burden, with high incidence and/or severity of diarrhea for some agents that inhibit epidermal growth factor receptor and receptor tyrosine kinases. Neratinib is a pan-HER tyrosine kinase inhibitor approved for breast cancer treatment and causes severe diarrhea in >95% of patients. Crofelemer, a novel intestinal chloride ion channel modulator, is an approved antidiarrheal drug for symptomatic relief of noninfectious diarrhea in patients with HIV/AIDS receiving antiretroviral therapy. The objective of this study was to evaluate the effectiveness of crofelemer prophylaxis in reducing the incidence /severity of neratinib-induced diarrhea without concomitant administration of loperamide in female beagle dogs. A pilot study using 3 dogs determined a maximum daily tolerated dose of neratinib was between 40 and 80 mg; this dose would induce a consistent incidence/severity of diarrhea without risking severe dehydration. In the definitive study, 24 female beagle dogs (8/group) received neratinib once daily and placebo capsules (CTR) four times/day, or neratinib once daily and crofelemer 125 mg delayed-release tablets given two times (BID), or neratinib once daily and crofelemer 125 mg delayed-release tablets given four times per day (QID). Fecal scores were collected twice daily using an established canine stool scoring scale called the Purina Fecal Scoring (PFS) System. After 28 days, using analysis of covariance (ANCOVA), dogs in the CTR group had a significantly higher average number of weekly loose/watery stools (PFS of 6 or 7) when compared to either crofelemer BID (8.71±2.2 vs. 5.96±2.2, p = 0.028) or crofelemer QID (8.70±2.2 vs. 5.74±2.2, p = 0.022) treatment groups. The average number of weekly loose/watery stools were not different between the crofelemer BID and QID treatment groups (p = 0.84). This study showed that crofelemer prophylaxis reduced the incidence/severity of neratinib-associated diarrhea in female beagle dogs without the need for any loperamide administration.

Toxicity and Toxicokinetics of a Four-Week Repeated Gavage of Levamisole in Male Beagle Dogs: A Good Laboratory Practice Study.

Levamisole (LVM) is considered an immunomodulatory agent that has the potential to treat various cancer and inflammation diseases. However, there is still much debate surrounding the toxicokinetic and toxicological information of LVM. Therefore, it is crucial to assess its toxicity to provide useful data for future human LVM risk assessments. In this study, a barrier environment was established under the guidance of good laboratory practice (GLP) at the Fujian Center for New Drug Safety Evaluation. Male beagle dogs were orally administered with 5, 15, and 30 mg/kg of LVM daily for four weeks. Toxicity assessment was based on various factors such as mortality, clinical signs, food and water consumption, body weight, body temperature, electrocardiogram, ophthalmological examination, hematology, serum biochemistry, organ/body coefficients, histopathological study, and toxicokinetic analysis. The results of this study showed that LVM did not exhibit any significant toxicological effects on beagle dogs at the exposure levels tested. A no observed adverse effect level (NOAEL) of LVM was set at 30 mg/kg/day for male beagle dogs, which is equivalent to a 12-fold clinical dose in humans. Moreover, the repeated exposure to LVM for four weeks did not lead to any bioaccumulation. These findings provide valuable insights for future human LVM risk assessments.

Application of Y-Z deformable magnetic ring for recanalization of transanal single-access rectal stricture.

Magnetic compression anastomosis has been reported to have remarkable clinical outcomes. Here, we tested the applicability of a Y-Z deformable magnetic ring (DMR) for non-surgical manipulation of rectal stenosis (RS) in a beagle dog model under a transanal single-access condition. RS was modeled in 8 beagle dogs using partial ligation with silk thread. Under X-ray guidance, the Y-Z DMR was positioned at the proximal and distal ends of the RS, and the magnetic ring was bent into an "O" shape, such that the two rings were magnetically attracted. Operation time, complications during or after operation, and discharge time of the magnetic rings were recorded. The anastomosis bursting pressure was measured two weeks after removing the rings, and its formation was assessed through gross and histological examination. Partial ligation with a silk thread successfully established the canine RS model. After Y-Z DMR installation, the magnetic ring was successfully reconfigured from an "S" to an "O" shape. Strong attraction existed between the rings. The operation time was 9-15min (average: 11.75 ± 1.98min). No rectal bleeding or perforation occurred during or after operation. The ring was naturally expelled 7-10days after surgery. A pressure of > 300mmHg was recorded at the point of anastomosis rupture. The rectal anastomosis appeared to have healed properly on the surface, which was confirmed histologically, signifying the success of this procedure. A Y-Z DMR facilitated the successful recanalization of transanal single-channel RS without needing surgery in an animal model.

Endothelial membrane mimetic coating modified dialyzer for hemocompatible and anticoagulant-free hemodialysis

Current hemodialysis requires a dilemmatic balance between under- and over-heparinization to prevent extracorporeal circuit clotting and bleeding complications. Here we report an endothelial membrane mimetic coating (EMMC) strategy to replace the systemic heparinization by enhancing the hemocompatibility and anticoagulation property of all the blood contacting surfaces. The EMMC is created by precoating of polydopamine, multi-point anchoring of a sulfobetaine and carboxyl side-chain copolymer (PSBC) and grafting of unfractionated heparin (UFH). The multi-point anchored PSBC layer forms an ultra-thin cell outer membrane zwitterion mimicking interface to enhance hemocompatibility, while the grafted UFH molecules mimic anticoagulant molecules attached on endothelial membrane to endow superior anticoagulation activity. Compared to a commercial polysulfone (PSf) dialysis membrane, the EMMC coated membrane can reduce protein adsorption, platelet adhesion and complement activation by 94.1 %, 98.9 % and 77 %, respectively. Meanwhile, anticoagulation properties, including clotting time, surface thrombus formation time and thrombin inactivation efficacy, are significantly improved compared to currently reported heparin coatings. More importantly, anticoagulant-free extracorporeal circulation using the EMMC modified PSf dialyzer circuit in a beagle dog model was performed smoothly for 2 h without any observable thrombus. Furthermore, main dialysis parameters of the modified hemodialyzer were not decreased. In conclusion, this highly hemocompatible and strong anticlotting endothelial membrane mimetic coating has great potential to replace the systemic heparinization in hemodialysis.