Borg's exertion scale did not coincide with ventilatory anaerobic threshold in atrial fibrillation patients with restored sinus rhythm after ablation.

The determination of precise exercise intensity is essential for effective exercise rehabilitation. The Borg rating of perceived exertion category ratio (CR) scale is utilized to prescribe an appropriate level of exertion intensity. A Borg CR of approximately 13 coincides with the ventilatory aerobic threshold (VAT). Patients with atrial fibrillation (AF) exhibit various symptoms. We hypothesized that the workload at Borg CR13 (Borg CR13-Watt) differs from the workload at the VAT level (VAT-Watt) in AF patients with restored sinus rhythm (SR) following ablation. Accordingly, the relationship between Borg CR13-Watt and VAT-Watt was studied in patients with restored SR. Cardiopulmonary exercise testing (CPET) was performed at 101±88 days after ablation in 150 patients using a bicycle ergometer. No adverse events were observed during CPET. Borg CR13-Watt was significantly higher than VAT-Watt (67.2±27.8 Watt vs. 54.7±17.6 Watt, P<0.0001). Borg CR13-Watt showed significant linear regression with VAT-Watt (regression coefficient, 0.49, P<0.01; correlation coefficient, 0.80, P<0.01). Higher Borg CR13-Watt was associated with greater differences between Borg CR13-Watt and VAT-Watt (ΔWatt). The Bland-Altman plot showed nonconcordance between the two. Male sex, use of antiarrhythmic drugs, and smoking had contributed to the increased ΔWatt. Duration from ablation to time of CPET did not correlate with ΔWatt. Therefore, Borg CR13-Watt did not coincide with VAT-Watt in patients with restored SR. Higher Borg CR13-Watt was associated with greater ΔWatt. Prescribing exertion intensity as determined solely by perceived exertion is inadequate. CPET is required to determine the precise exercise intensity in AF patients with restored SR after ablation.

Exploring sleep heart rate variability: linear, nonlinear, and circadian rhythm perspectives.

Background: Heart rate variability (HRV) is believed to possess the potential for disease detection. However, early identification of heart disease remains challenging, as HRV analysis in dogs primarily reflects the advanced stages of the disease. Hypothesis/objective: The aim of this study is to compare 24-h HRV with sleep HRV to assess the potential utility of sleep HRV analysis. Animals: Thirty healthy dogs with no echocardiographic abnormalities were included in the study, comprising 23 females and 7 males ranging in age from 2 months to 8 years (mean [standard deviation], 1.4 [1.6]). Methods: This study employed a cross-sectional study. 24-h HRV and sleep HRV were measured from 48-h Holter recordings. Both linear analysis, a traditional method of heart rate variability analysis, and nonlinear analysis, a novel approach, were conducted. Additionally, circadian rhythm parameters were assessed. Results: In frequency analysis of linear analysis, the parasympathetic index nHF was significantly higher during sleep compared to the mean 24-h period (mean sleep HRV [standard deviation] vs. mean 24 h [standard deviation], 95% confidence interval, p value, r-family: 0.24 [0.057] vs. 0.23 [0.045], 0.006-0.031, p = 0.005, r = 0.49). Regarding time domain analysis, the parasympathetic indices SDNN and RMSSD were also significantly higher during sleep (SDNN: 179.7 [66.9] vs. 156.6 [53.2], 14.5-31.7, p < 0.001, r = 0.71 RMSSD: 187.0 [74.0] vs. 165.4 [62.2], 13.2-30.0, p < 0.001, r = 0.70). In a geometric method of nonlinear analysis, the parasympathetic indices SD1 and SD2 showed significantly higher values during sleep (SD1: 132.4 [52.4] vs. 117.1 [44.0], 9.3-21.1, p < 0.001, r = 0.70 SD2: 215.0 [80.5] vs. 185.9 [62.0], 17.6-40.6, p < 0.001, r = 0.69). Furthermore, the circadian rhythm items of the parasympathetic indices SDNN, RMSSD, SD1, and SD2 exhibited positive peaks during sleep. Conclusion: The findings suggest that focusing on HRV during sleep can provide a more accurate representation of parasympathetic activity, as it captures the peak circadian rhythm items.

Evaluation of Alacepril Administration in Canine Patent Ductus Arteriosus According to Plasma Chymase Activity.

Chymase in the renin-angiotensin system (RAS) actively contributes to cardiac disease progression. Chymase is activated to produce angiotensin II during tissue injury and is involved in hemodynamics. A recent study demonstrated that plasma chymase activity reflects hemodynamic changes and aids in understanding patent ductus arteriosus (PDA) pathophysiology. The present study examined the relationship between plasma chymase activity and the administration of angiotensin-converting enzyme (ACE) inhibitor. Alacepril was administered to 13 puppies with PDA. Conventional echocardiographic parameters and non-invasive blood pressure were measured before and after medication. Plasma chymase activity was calculated using the colorimetric absorbance method. Plasma chymase activity significantly increased, but blood pressure significantly decreased. We detected an increase in plasma chymase activity due to ACE inhibition in PDA cases treated with alacepril. Plasma chymase activity was affected and altered by alacepril. In veterinary medicine, plasma chymase activity may be a novel method for assessing the pathology of and therapy for cardiac diseases.

Potential protective effects of L-carnitine against myocardial ischemia/reperfusion injury in a rat model.

Myocardial ischemia/reperfusion (I/R) injury is a growing concern for global public health. This study seeks to explore the potential protective effects of L-carnitine (LC) against heart ischemia-reperfusion injury in rats. To induce I/R injury, the rat hearts underwent a 30-min ligation of the left anterior descending coronary artery, followed by 24 h of reperfusion. We evaluated cardiac function through electrocardiography and heart rate variability (HRV) and conducted pathological examinations of myocardial structure. Additionally, the study investigated the influence of LC on myocardial apoptosis, inflammation, and oxidative stress in the context of I/R injury. The results show that pretreatment with LC led to improvements in the observed alterations in ECG waveforms and HRV parameters in the nontreated ischemic reperfusion model group, although most of these changes did not reach statistical significance. Similarly, although without a significant difference, LC reduced the levels of proinflammatory cytokines when compared to the values in the nontreated ischemic rat group. Furthermore, LC restored the reduced expressions of SOD1, SOD2, and SOD3. Additionally, LC significantly reduced the elevated Bax expressions and showed a nonsignificant increase in Bcl-2 expression, resulting in a favorable adjustment of the Bcl-2/Bax ratio. We also observed a significant enhancement in the histological appearance of cardiac muscles, a substantial reduction in myocardial fibrosis, and suppressed CD3 + cell proliferation in the ischemic myocardium. This small-scale, experimental, in vivo study indicates that LC was associated with enhancements in the pathological findings in the ischemic myocardium in the context of ischemia/reperfusion injury in this rat model. Although statistical significance was not achieved, LC exhibits potential and beneficial protective effects against I/R injury. It does so by modulating the expression of antioxidative and antiapoptotic genes, inhibiting the inflammatory response, and enhancing autonomic balance, particularly by increasing vagal tone in the heart. Further studies are necessary to confirm and elaborate on these findings.

Reproducibility of cardiopulmonary exercise testing between one after and 1-3 weeks after elective percutaneous coronary intervention.

Prompt prescription and early initiation of exercise training are essential for patients undergoing elective percutaneous coronary intervention (PCI). We hypothesized that cardiopulmonary exercise testing (CPET) parameters determined the day after elective PCI during hospitalization would not differ from those obtained 1-3 weeks post-PCI in patients with stable coronary heart disease (CHD). CPET was performed the day after and 1-3 weeks (13±4.6; 7-21 days) after PCI. CPET was performed with a bicycle ergometer up to the ventilatory aerobic threshold (VAT) on the day after PCI. Symptom-limited CPET was conducted 1-3 weeks after PCI. No complications arose from the tests. There were no significant differences in %VAT (next day: 88.6±16.7 vs. 1-3 weeks later: 91.4%±18.7%), the workload at the VAT (51.8±11.0 W vs. 52.9± 11.6 W), heart rate (HR) at the VAT (95.3±105 beats/min vs. 94.1±11.3 beats/min), or metabolic equivalent (METs) at the VAT (3.69±0.69 vs. 3.84±0.78) between the two sessions. The slope of linear regression for two repeated measurements was close to 1 (%VAT, 1.02; workload at the VAT, 0.95; METs at the VAT, 1.03), except for HR (0.70). Bland-Altman plots revealed the reproducibility of all four CPET measurements between the two sessions. In conclusion, CPET up to the VAT can be performed safely 1-day post-PCI in patients with stable CHD. CPET parameters do not significantly differ between testing performed the day after and 1-3 weeks after PCI. Next-day CPET during hospitalization after PCI may enable prompt exercise prescription without the need for another CPET 1-3 weeks later.

Adipose Stem Cell-Seeded Decellularized Porcine Pericardium: A Promising Functional Biomaterial to Synergistically Restore the Cardiac Functions Post-Myocardial Infarction.

Myocardial infarction (MI) is a serious cardiovascular disease as the leading cause of death globally. Hence, reconstruction of the cardiac tissue comes at the forefront of strategies adopted to restore heart functions following MI. In this investigation, we studied the capacity of rat adipose-derived mesenchymal stem cells (r-AdMSCs) and decellularized porcine pericardium (DPP) to restore heart functions in MI animals. MI was induced in four different groups, three of which were treated either using DPP (MI-DPP group), stem cells (MI-SC group), or both (MI-SC/DPP group). Cardiac functions of these groups and the Sham group were evaluated using echocardiography, the intraventricular pressure gradient (IVPG) on weeks 2 and 4, and intraventricular hemodynamics on week 4. On day 31, the animals were euthanized for histological analysis. Echocardiographic, IVPG and hemodynamic findings indicated that the three treatment strategies shared effectively in the regeneration process. However, the MI-SC/DPP group had a unique synergistic ability to restore heart functions superior to the other treatment protocols. Histology showed that the MI-SC/DPP group presented the lowest (p < 0.05) degeneration score and fibrosis % compared to the other groups. Conclusively, stem cell-seeded DPP is a promising platform for the delivery of stem cells and restoration of heart functions post-MI.

Vascular ring anomaly with a right patent ductus arteriosus and a left aortic arch in a juvenile cat.

This paper reports the clinical findings and surgical treatment of feline right patent ductus arteriosus (RPDA) with a left aortic arch. A two-month-old female Maine Coon was referred for an investigation of regurgitation after weaning. RPDA with a left aortic arch was diagnosed based on the echocardiographic and computed tomography (CT) findings. A right-fourth intercostal thoracotomy was found to be an appropriate approach to the duct. Preoperative diagnosis is crucial and diagnostic imaging, including radiography, echocardiography, and cardiac CT examination, is essential for determining if the aortic arch is right or left.

Non-Invasive Assessment of the Intraventricular Pressure Using Novel Color M-Mode Echocardiography in Animal Studies: Current Status and Future Perspectives in Veterinary Medicine.

The assessment of diastolic function has received great interest in order to comprehend its crucial role in the pathophysiology of heart failure and for the early identification of cardiac events. Silent changes in the intraventricular flow (IVF) dynamics occur before the deterioration of the cardiac wall, although they cannot be detected using conventional echocardiography. Collective information on left ventricular (LV) pressures throughout the cardiac cycle has great value when dealing with patients with altered hemodynamics. Accurate pressure measurement inside the ventricle can be obtained by invasive methods to determine the LV diastolic pressures, which reflect the myocardial relaxation and compliance. However, catheterization is only feasible in the laboratory setting and is not suitable for clinical use due to its disadvantages. In contrast, echocardiography is simple, safe, and accessible. Color M-mode echocardiography (CMME) is an advanced cardiac evaluation technique that can measure the intraventricular pressure differences (IVPDs) and intraventricular pressure gradients (IVPGs) based on the Doppler shift of the IVF. Recently, the assessment of IVPD and IVPG has gained growing interest in the cardiovascular literature in both animal and human studies as a non-invasive method for the early diagnosis of cardiac dysfunctions, especially diastolic ones. The usability of IVPD and IVPG has been reported in various surgically induced heart failure or pharmacologically altered cardiac functions in rats, dogs, cats, and goats. This report aims to give an overview of the current studies of CMME-derived IVPD and IVPG in animal studies and its feasibility for clinical application in veterinary practice and to provide the prospects of the technique's ability to improve our understanding.

Impact of vericiguat on baroreflex-mediated sympathetic circulatory regulation: An open-loop analysis.

AIMS: To quantify in vivo the effects of the soluble guanylate cyclase (sGC) stimulator, vericiguat, on autonomic cardiovascular regulation in comparison with the nitric oxide (NO) donor, sodium nitroprusside. METHODS: In anesthetized Wistar-Kyoto rats, baroreflex-mediated changes in sympathetic nerve activity (SNA), arterial pressure (AP), central venous pressure (CVP), and aortic flow (AoF) were examined before and during the intravenous continuous administration (10 µg·kg-1·min-1) of vericiguat or sodium nitroprusside (n = 8 each). Systemic vascular resistance (SVR) was calculated as SVR = (AP-CVP) / AoF. RESULTS: Neither vericiguat nor sodium nitroprusside affected fitted parameters of the baroreflex-mediated SNA response. Both vericiguat and sodium nitroprusside decreased the AP mainly through their peripheral effects. Vericiguat halved the slope of the SNA-SVR relationship from 0.012 ± 0.002 to 0.006 ± 0.002 mmHg·min·mL-1·%-1 (P = 0.008), whereas sodium nitroprusside caused a near parallel downward shift in the SNA-SVR relationship with a reduction of the SVR intercept from 1.235 ± 0.187 to 0.851 ± 0.123 mmHg·min/mL (P = 0.008). CONCLUSION: Neither vericiguat nor sodium nitroprusside significantly affected the baroreflex-mediated SNA response. The vasodilative effect of vericiguat became greater toward high levels of SNA and AP, possibly reflecting the increased sGC sensitivity to endogenous NO. By contrast, the effect of sodium nitroprusside was more uniform over the range of SNA. These results help better understand cardiovascular effects of vericiguat.

Effect of trehalose on heart functions in rats model after myocardial infarction: assessment of novel intraventricular pressure and heart rate variability.

Background: Myocardial infarctions remain a leading cause of global deaths. Developing novel drugs to target cardiac remodeling after myocardial injury is challenging. There is an increasing interest in exploring natural cardioprotective agents and non-invasive tools like intraventricular pressure gradients (IVPG) and heart rate variability (HRV) analysis in myocardial infarctions. Trehalose (TRE), a natural disaccharide, shows promise in treating atherosclerosis, myocardial infarction, and neurodegenerative disorders. Objectives: The objective of this study was to investigate the effectiveness of TRE in improving cardiac functions measured by IVPG and HRV and reducing myocardial remodeling following myocardial infarction in rat model. Methods: Rats were divided into three groups: sham, myocardial infarction (MI), and trehalose-treated MI (TRE) groups. The animals in the MI and TRE groups underwent permanent ligation of the left anterior descending artery. The TRE group received 2% trehalose in their drinking water for four weeks after the surgery. At the end of the experiment, heart function was assessed using conventional echocardiography, novel color M-mode echocardiography for IVPG evaluation, and HRV analysis. After euthanasia, gross image scoring, histopathology, immunohistochemistry, and quantitative real-time PCR were performed to evaluate inflammatory reactions, oxidative stress, and apoptosis. Results: The MI group exhibited significantly lower values in multiple IVPG parameters. In contrast, TRE administration showed an ameliorative effect on IVPG changes, with results comparable to the sham group. Additionally, TRE improved HRV parameters, mitigated morphological changes induced by myocardial infarction, reduced histological alterations in wall mass, and suppressed inflammatory reactions within the infarcted heart tissues. Furthermore, TRE demonstrated antioxidant, anti-apoptotic and anti-fibrotic properties. Conclusion: The investigation into the effect of trehalose on a myocardial infarction rat model has yielded promising outcomes, as evidenced by improvements observed through conventional echocardiography, histological analysis, and immunohistochemical analysis. While minor trends were noticed in IVPG and HRV measurements. However, our findings offer valuable insights and demonstrate a correlation between IVPG, HRV, and other traditional markers of echo assessment in the myocardial infarction vs. sham groups. This alignment suggests the potential of IVPG and HRV as additional indicators for future research in this field.

Comparison of Bovine- and Porcine-Derived Decellularized Biomaterials: Promising Platforms for Tissue Engineering Applications.

Animal-derived xenogeneic biomaterials utilized in different surgeries are promising for various applications in tissue engineering. However, tissue decellularization is necessary to attain a bioactive extracellular matrix (ECM) that can be safely transplanted. The main objective of the present study is to assess the structural integrity, biocompatibility, and potential use of various acellular biomaterials for tissue engineering applications. Hence, a bovine pericardium (BP), porcine pericardium (PP), and porcine tunica vaginalis (PTV) were decellularized using a Trypsin, Triton X (TX), and sodium dodecyl sulfate (SDS) (Trypsin + TX + SDS) protocol. The results reveal effective elimination of the cellular antigens with preservation of the ECM integrity confirmed via staining and electron microscopy. The elasticity of the decellularized PP (DPP) was markedly (p < 0.0001) increased. The tensile strength of DBP, and DPP was not affected after decellularization. All decellularized tissues were biocompatible with persistent growth of the adipose stem cells over 30 days. The staining confirmed cell adherence either to the peripheries of the materials or within their matrices. Moreover, the in vivo investigation confirmed the biocompatibility and degradability of the decellularized scaffolds. Conclusively, Trypsin + TX + SDS is a successful new protocol for tissue decellularization. Moreover, decellularized pericardia and tunica vaginalis are promising scaffolds for the engineering of different tissues with higher potential for the use of DPP in cardiovascular applications and DBP and DPTV in the reconstruction of higher-stress-bearing abdominal walls.

Stimuli-responsive hydrogels: smart state of-the-art platforms for cardiac tissue engineering.

Biomedicine and tissue regeneration have made significant advancements recently, positively affecting the whole healthcare spectrum. This opened the way for them to develop their applications for revitalizing damaged tissues. Thus, their functionality will be restored. Cardiac tissue engineering (CTE) using curative procedures that combine biomolecules, biomimetic scaffolds, and cells plays a critical part in this path. Stimuli-responsive hydrogels (SRHs) are excellent three-dimensional (3D) biomaterials for tissue engineering (TE) and various biomedical applications. They can mimic the intrinsic tissues' physicochemical, mechanical, and biological characteristics in a variety of ways. They also provide for 3D setup, adequate aqueous conditions, and the mechanical consistency required for cell development. Furthermore, they function as competent delivery platforms for various biomolecules. Many natural and synthetic polymers were used to fabricate these intelligent platforms with innovative enhanced features and specialized capabilities that are appropriate for CTE applications. In the present review, different strategies employed for CTE were outlined. The light was shed on the limitations of the use of conventional hydrogels in CTE. Moreover, diverse types of SRHs, their characteristics, assembly and exploitation for CTE were discussed. To summarize, recent development in the construction of SRHs increases their potential to operate as intelligent, sophisticated systems in the reconstruction of degenerated cardiac tissues.

Secondary right atrial thrombosis in three dogs: Antithrombotics therapy and echocardiographic follow-up.

Three dogs were diagnosed with right atrial thrombosis, thought to be secondary to systemic diseases. Specifically, two cases had hyperadrenocorticism and one case was diagnosed with pancreatitis with acute renal injury. In all cases, the thrombi were found within the right atrium, necessitating a differentiation from cardiac neoplasia. In all three cases, the structures assumed to be thrombi had irregular margins with interspersed hypoechoic regions, which were later confirmed as thrombi based on the responsiveness to therapy. All three cases were prescribed with the combination of clopidogrel and rivaroxaban.The thrombi gradually disappeared after initiation of the combination therapy. Complete resolution of right atrial thrombosis was noted in each dog treated with clopidogrel and rivaroxaban. This combination therapy appears to be safe and well tolerated. Diligent observation of the echocardiographic findings and clinical course allows the diagnosis of thrombosis.

Cephalic and saphenous venous blood collected by continuous heating of the paws compared with arterial blood for measurement of blood gas values in well-perfused dogs.

BACKGROUND: "Arterialization" of the dorsal hand vein is well-established in human medicine, but not in veterinary medicine. OBJECTIVES: To compare cephalic and saphenous venous blood collected by continuously heating the paws to 37°C ("arterialization"), with arterial blood (AB) for measurement of blood gas variables in well-perfused dogs. ANIMALS: Eight healthy dogs. METHODS: Experimental study. Fore and hind paws were continuously heated to 37°C to "arterialize" cephalic and saphenous venous blood. AB and "arterialized" cephalic and saphenous venous blood (ACV and ASV, respectively) were simultaneously collected from lightly anesthetized dogs with induced metabolic and respiratory acid-base disorders. The pH, partial pressures of carbon dioxide (PCO2 ) and oxygen (PO2 ), bicarbonate concentration [HCO3 - ], and base excess (BE) were measured once in each state. Systolic blood pressure was maintained above 100 mm Hg. The AB, ACV, and ASV values were compared. RESULTS: The pH, [HCO3 - ], and BE values had no significant difference and good agreement, the PCO2 values had a strong correlation (correlation coefficient of .91-1.00), and the PO2 values had a significant difference (P < .01) and poor agreement between AB and ACV, and between AB and ASV. The PCO2 values of ASV overestimated those of AB by ~3.0 mm Hg, which was considered within clinically allowable limits, while those of ACV were not within clinically allowable limits. CONCLUSIONS AND CLINICAL IMPORTANCE: Under experimental conditions, the ASV samples were more identical to the AB samples than the ACV samples for pH, PCO2 , [HCO3 - ], and BE values in well-perfused dogs. The saphenous vein is suitable for "arterialization."

Impact of Adipose Tissue Depot Harvesting Site on the Multilineage Induction Capacity of Male Rat Adipose-Derived Mesenchymal Stem Cells: An In Vitro Study.

Recently, substantial attention has been paid toward adipose-derived mesenchymal stem cells (AdMSCs) as a potential therapy in tissue engineering and regenerative medicine applications. Rat AdMSCs (r-AdMSCs) are frequently utilized. However, the influence of the adipose depot site on the multilineage differentiation potential of the r-AdMSCs is still ambiguous. Hence, the main objective of this study was to explore the influence of the adipose tissue harvesting location on the ability of r-AdMSCs to express the stem-cell-related markers and pluripotency genes, as well as their differentiation capacity, for the first time. Herein, we have isolated r-AdMSCs from the inguinal, epididymal, peri-renal, and back subcutaneous fats. Cells were compared in terms of their phenotype, immunophenotype, and expression of pluripotency genes using RT-PCR. Additionally, we investigated their potential for multilineage (adipogenic, osteogenic, and chondrogenic) induction using special stains confirmed by the expression of the related genes using RT-qPCR. All cells could positively express stem cell marker CD 90 and CD 105 with no significant in-between differences. However, they did not express the hematopoietic markers as CD 34 and CD 45. All cells could be induced successfully. However, epididymal and inguinal cells presented the highest capacity for adipogenic and osteogenic differentiation (21.36-fold and 11.63-fold for OPN, 29.69-fold and 26.68-fold for BMP2, and 37.67-fold and 22.35-fold for BSP, respectively, in epididymal and inguinal cells (p < 0.0001)). On the contrary, the subcutaneous cells exhibited a superior potential for chondrogenesis over the other sites (8.9-fold for CHM1 and 5.93-fold for ACAN, (p < 0.0001)). In conclusion, the adipose tissue harvesting site could influence the differentiation capacity of the isolated AdMSCs. To enhance the results of their employment in various regenerative cell-based therapies, it is thus vital to take the collection site selection into consideration.

A review on experimental surgical models and anesthetic protocols of heart failure in rats.

Heart failure (HF) is a serious health and economic burden worldwide, and its prevalence is continuously increasing. Current medications effectively moderate the progression of symptoms, and there is a need for novel preventative and reparative treatments. The development of novel HF treatments requires the testing of potential therapeutic procedures in appropriate animal models of HF. During the past decades, murine models have been extensively used in fundamental and translational research studies to better understand the pathophysiological mechanisms of HF and develop more effective methods to prevent and control congestive HF. Proper surgical approaches and anesthetic protocols are the first steps in creating these models, and each successful approach requires a proper anesthetic protocol that maintains good recovery and high survival rates after surgery. However, each protocol may have shortcomings that limit the study's outcomes. In addition, the ethical regulations of animal welfare in certain countries prohibit the use of specific anesthetic agents, which are widely used to establish animal models. This review summarizes the most common and recent surgical models of HF and the anesthetic protocols used in rat models. We will highlight the surgical approach of each model, the use of anesthesia, and the limitations of the model in the study of the pathophysiology and therapeutic basis of common cardiovascular diseases.

Preliminary report of spinal cord injuries resulting from inappropriate microchip implantation in two puppies.

Since the revised Animal Welfare and Management Law in Japan became effective on June 1st, 2022, it became mandatory for pet dogs and cats to have microchips implanted and registered prior to be sold. Two cases of spinal cord injury as the result of inappropriate microchip implantation in puppies were referred to our facility, of which were diagnosed by cervical spinal radiography and computed tomography (CT). While adverse reactions following microchip implantation are rare, the possibility of iatrogenic spinal cord injury remains a serious complication. This is the first report of adverse reactions following microchip implantation in Japan, and it alerts the possibility of iatrogenic spinal cord injury secondary to inappropriate microchip implantation, where adequate training and extra caution is crucial especially in small light-weight animals.

Effect of experimental periodontitis on cardiac functions: a comprehensive study using echocardiography, hemodynamic analysis, and histopathological evaluation in a rat model.

Introduction: Periodontitis is a prevalent and severe dental condition characterized by the gradual degradation of the bone surrounding the teeth. Over the past two decades, numerous epidemiological investigations have suggested a potential link between periodontitis and cardiovascular disease. However, the complex mechanistic relationship between oral health issues and cardiovascular disorders remains unclear. Aim: This study aimed to explore comprehensively the cardiac function through various methods, including conventional echocardiography, intraventricular pressure gradient (IVPG) analysis, speckle tracking echocardiography (STE), and hemodynamics analysis. Methods: Ligature-induced periodontitis was established in a group of rats while the second group served as sham. The successful establishment of the periodontitis model was confirmed through staining and radiographic examination of the affected mandibles. Results: X-ray films and methylene blue staining revealed alveolar bone resorption in the affected first molar in the model rats, confirming the successful induction of periodontitis. The rats with periodontitis displayed a decrease in ejection fraction compared to the sham group, accompanied by a decrease in mid-to-apical IVPG and mid IVPG. Lower values of strain rate were recorded in the apical segment of the septum, the middle segment of the septum, and the basal segment of the lateral free wall in the periodontitis group, which was associated with histopathological examination showing some degree of myocardial tissue damage. Conversely, rats with periodontitis showed an increase in heart rate, end-systolic volume, and arterial elastance when compared to the sham rats. However, they also exhibited a decrease in stroke work, stroke volume, cardiac output, and end-systolic pressure. Conclusion: This study suggests that experimental periodontitis may lead to cardiac dysfunction especially compromised systolic function and myocardial relaxation, potentially indicating an increased risk of cardiovascular events in clinical periodontitis cases. The comprehensive assessment of cardiac function, hemodynamics, and histopathological evaluation underscores the profound impact of periodontitis on heart functions within this specific experimental model.

Novel protocol to establish the myocardial infarction model in rats using a combination of medetomidine-midazolam-butorphanol (MMB) and atipamezole.

Background: Myocardial infarction (MI) is one of the most common cardiac problems causing deaths in humans. Previously validated anesthetic agents used in MI model establishment are currently controversial with severe restrictions because of ethical concerns. The combination between medetomidine, midazolam, and butorphanol (MMB) is commonly used in different animal models. The possibility of MMB combination to establish the MI model in rats did not study yet which is difficult because of severe respiratory depression and delayed recovery post-surgery, resulting in significant deaths. Atipamezole is used to counter the cardiopulmonary suppressive effect of MMB. Objectives: The aim of the present study is to establish MI model in rats using a novel anesthetic combination between MMB and Atipamezole. Materials and methods: Twenty-five Sprague Dawley (SD) rats were included. Rats were prepared for induction of the Myocardial infarction (MI) model through thoracotomy. Anesthesia was initially induced with a mixture of MMB (0.3/5.0/5.0 mg/kg/SC), respectively. After endotracheal intubation, rats were maintained with isoflurane 1% which gradually reduced after chest closing. MI was induced through the left anterior descending (LAD) artery ligation technique. Atipamezole was administered after finishing all surgical procedures at a dose rate of 1.0 mg/kg/SC. Cardiac function parameters were evaluated using ECG (before and after atipamezole administration) and transthoracic echocardiography (before and 1 month after MI induction) to confirm the successful model. The induction time, operation time, and recovery time were calculated. The success rate of the MI model was also calculated. Results: MI was successfully established with the mentioned anesthetic protocol through the LAD ligation technique and confirmed through changes in ECG and echocardiographic parameters after MI. ECG data was improved after atipamezole administration through a significant increase in heart rate (HR), PR Interval, QRS Interval, and QT correction (QTc) and a significant reduction in RR Interval. Atipamezole enables rats to recover voluntary respiratory movement (VRM), wakefulness, movement, and posture within a very short time after administration. Echocardiographic ally, MI rats showed a significant decrease in the left ventricular wall thickness, EF, FS, and increased left ventricular diastolic and systolic internal diameter. In addition, induction time (3.440 ± 1.044), operation time (29.40 ± 3.663), partial recovery time (10.84 ± 3.313), and complete recovery time (12.36 ± 4.847) were relatively short. Moreover, the success rate of the anesthetic protocol was 100%, and all rats were maintained for 1 month after surgery with a survival rate of 88%. Conclusion: Our protocol produced a more easy anesthetic effect and time-saving procedures with a highly successful rate in MI rats. Subcutaneous injection of Atipamezole efficiently counters the cardiopulmonary side effect of MMB which is necessary for rapid recovery and subsequently enhancing the survival rate during the creation of the MI model in rats.