Animal Preparation Research Articles

Surface electromyography: A pilot study in canine spinal muscles

In veterinary practice, rehabilitation modalities are often used to help in the recovery of animals affected by InterVertebral Disc Disease (IVDD), a condition frequently observed in chondrodystrophic dog breeds and can lead to Spinal Cord Injury (SCI), resulting in pain, motor impairments and neurological deficits, but there is a lack of objective assessment tools for patient evolution. In this work, an innovative approach using surface ElectroMyoGraphy (sEMG) is proposed to be applied in the field of veterinary medicine rehabilitation. The observed results are thought to be a direct result of nerve compression, leading to unusual patterns of muscle activation; this phenomenon can be attributed to muscle denervation, where the loss of Motor Units (MU) is the primary cause. This is thought to be responsible for the decrease in recorded sEMG amplitude and the increase in frequency observed in the pathological group.•This study involved rigorous animal preparation and signal acquisition protocols, involving multiple exercises and sub-movements, which were subsequently analysed.•RMSA is most used metric to analyse amplitude in sEMG signals, as it results in a more representative measurement of the signal variability than the Mean amplitude or the Standard Deviation.

Simultaneous optical imaging of gastric slow waves and contractions in the in vivo porcine stomach.

Gastric peristalsis is governed by electrical "slow waves" generally assumed to travel from proximal to distal stomach (antegrade propagation) in symmetric rings. Although alternative slow-wave patterns have been correlated with gastric disorders, their mechanisms and how they alter contractions remain understudied. Optical electromechanical mapping, a developing field in cardiac electrophysiology, images electrical and mechanical physiology simultaneously. Here, we translate this technology to the in vivo porcine stomach. Stomachs were surgically exposed and a fluorescent dye (di-4-ANEQ(F)PTEA) that transduces the membrane potential (Vm) was injected through the right gastroepiploic artery. Fluorescence was excited by LEDs and imaged with one or two 256 × 256 pixel cameras. Motion artifact was corrected using a marker-based motion-tracking method and excitation ratiometry, which cancels common-mode artifact. Tracking marker displacement also enabled gastric deformation to be measured. We validated detection of electrical activation and Vm morphology against alternative nonoptical technologies. Nonantegrade slow waves and propagation direction differences between the anterior and posterior stomach were commonly present in our data. However, sham experiments suggest they were a feature of the animal preparation and not an artifact of optical mapping. In experiments to demonstrate the method's capabilities, we found that repolarization did not always follow at a fixed time behind activation "wavefronts," which could be a factor in dysrhythmia. Contraction strength and the latency between electrical activation and contraction differed between antegrade and nonantegrade propagation. In conclusion, optical electromechanical mapping, which simultaneously images electrical and mechanical activity, enables novel questions regarding normal and abnormal gastric physiology to be explored.NEW & NOTEWORTHY This article introduces a novel method for imaging gastric electrophysiology and mechanical function simultaneously in anesthetized, open-abdomen pigs. We demonstrate it by observing propagating slow-wave depolarization and repolarization along with the strength, spatial distribution, and direction of contractions. In addition, we observe that in this animal preparation, slow waves often do not propagate from the proximal to distal stomach and are frequently asymmetric between the anterior and posterior sides of the stomach.

Test Of The Effectiveness Of Oral Administration Of Red Dragon Fruit (Hylocereus Polyrhizus) In Preventing Dyslipidemia In Male Wistar Rats (Rattus Norvegicus) Given A High High-Cholesterol Diet

Hyperlipidemia can result from obesity, which causes excess fat to build in the tissue under the skin and spread to other organs and tissues. Indonesia has an alarming dyslipidemia rate. Diet and exercise are vital. Hypolipidemia is in red dragon fruit (Hylocereus spp.) The study examined whether oral red dragon fruit extract prevented dyslipidemia in male Wistar rats (Rattus norvegicus) fed a high-cholesterol diet. This research used 24 mice as test animals. The research procedures included acclimation of the test animals, dragon fruit extract, phytochemical tests, preparation of the test animals, treatment with four groups, dyslipidemia parameter checks, histopathological preparations, and observations. Normal tests for total cholesterol, LDL, LSD, and HDL yielded p-values> 0.05. Homogeneity tests with a 5% significance level yielded p values < 0.05. This study's one-way Anova test yields a significance value of 0.000, or <0.05, whereas the post-hoc LSD test yields <0.05. The best red dragon fruit extract dose for lowering total and LDL cholesterol and raising HDL is 120 mg/mL. The phytochemical experiments on red dragon fruit extract (Hylocereus polyrhizus) show promise for improving the lipid profile.

Moringa oleifera extract affects the diameter of the Graafian follicles in female Mus musculus

HIGHLIGHTS This study unveils a dose-dependent relationship between Moringa leaf extract and increased Graafian follicle size in female mice. The significant positive effect of Moringa leaf extract on Graafian follicles suggests promising implications for fertility interventions, offering hope for individuals seeking natural treatment to address infertility challenges. ABSTRACT Objective: This study aimed to determine the effect of Moringa leaf extract (Moringa oleifera Lam.) on the diameter of Graafian follicles in female mice (Mus musculus). Materials and Methods: This study used experimental design, employing a cohort of 24 female mice of 20-25 grams in weight, aged between 2-3 months, and in good health. These subjects were divided into three treatment groups and subjected to oral doses of Moringa leaf extract at 300 mg/kg BW, 400 mg/kg BW, and 500 mg/kg BW over a 14-day period. The study procedures involved the preparation of the experimental animals, preparation of Moringa leaf extract, treatments administration, and the preparation of histological specimens. Subsequently, the diameters of Graafian follicles within each treatment group were measured. Data analysis were performed using the ANOVA test (p <0.05) followed with the Least Significance Difference (LSD) test utilizing the IBM SPSS software. Results: There were variations in Graafian follicle diameters across the experimental groups. The average diameters were 180.944 µm in the control group, 239.942 µm in treatment group 1, 315.006 µm in treatment group 2, and 396.650 µm in treatment group 3. This indicated that dose administration starting from 300 mg/kg, 400 mg/kg, and 500 mg/kg had an effect on the size of the follicle and antrum diameter. The number of granulosa cells was found to increase, as well as the size of the ovum. Conclusion: Moringa leaf extract in different doses has a significant positive effect on increasing the diameter of the Graafian follicles in female mice.

Abstract 4137: Feasibility of a novel image guided injection tool for non-surgical implantation of orthotopic tumors

Abstract The purpose of this study was to evaluate a novel device for non-surgical implantation of tumor cells using ultrasonic (US) image guidance. There are a variety of mouse model cancer types (e.g. sub-cu, orthotopic, genetically engineered). Orthotopic tumors are increasingly prevalent but usually require surgery, which reduces throughput and injures the surrounding anatomy. Injections are an alternative to surgery, but usually require image guidance or extensive training. US guided injection systems exist, but are suboptimal because they require significant training, as the US beam is not necessarily coplanar with needle location or trajectory, reducing accuracy and throughput. We tested a new approach to image guided injection which ensures that the US beam is coplanar with the needle. To test the efficacy of the image guided injection device across a variety of common orthotopic tumors, we delivered luc-tagged cells to the prostate (2.5e5 cells in 40 µL, PC3, N=8), liver (2e6 cells in 100 µL, Hep G2, N=5), and brain (1.75e5 cells in 100 µL, U87-MG, N=3). The brain tumor model was introduced via intracardiac injection to simulate metastases. Between 3 and 8 mice were injected for each tumor model. For injection, animals were anesthetized and positioned on motion stage. A 1 mL syringe was mounted to the adjustable injection gantry with the needle co-planar with the US beam, and the target organ was visualized with US. Cells were delivered to the targets using the US live stream as a guide. Between 1 to 3 weeks after the injections, tumors were confirmed via BLI with an IVIS (Revvity, Waltham, MA, USA). For each of the three tumor cell lines, animal preparation and injections could be performed in 10 mins by recently-trained novice users. All three cell lines could be effectively delivered to the orthotopic host tissues, and this was confirmed by using BLI of the cells. This study represents the first time a co-planar US beam and needle delivery mechanism was used for the purpose of non-surgical implantation of orthotopic tumors. Future developments of this platform could include improvements to automation of needle placement and trajectory to ensure successful payload delivery by novice users. Citation Format: Thomas M. Kierski, Juan D. Rojas, Nathan Beaumont, Theresa Charity, Robert D. Marek, Kenneth H. Young, Gregory M. Palmer, Ryan C. Gessner, Tomek J. Czernuszewicz. Feasibility of a novel image guided injection tool for non-surgical implantation of orthotopic tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4137.

CT‐based 3D reconstruction and basic anatomical analysis of the 3D anatomy of the air sac system in domestic birds

AbstractThe complex anatomy of the avian respiratory system makes it necessary to broaden our knowledge using modern imaging and reconstructional possibilities. The visualization of these structures can be used for clinical situations, in research or as teaching aids in veterinary education. For this we generated 3D models from diagnostic imaging data (computed tomography [CT] scans) of birds. We describe in detail a repeatable method of animal preparation for scanning, data handling and image analysis. CT scans with varying slice thickness and resolution were obtained in prone and supine body positions to analyse air sac morphology and volume changes relative to posture or sexual dimorphism in birds. The resulting data were prepared and analysed using a reconstructional software (3D Slicer) based on manual and semi‐automatic labelling and subsequent 3D models of the air sac system were created. The terminology employed has been referenced from the Nomina Anatomica Avium, Second Ed.

Using Small Molecules for Targeting Heavy Metals in Neurotoxicity and Neuroinflammation.

Pharmaceutical drugs, natural toxins, industrial chemicals, and various environmental toxins negatively impact the nervous system. A significant cause of many neurodegenerative diseases is neurotoxicity. Although trace amounts of heavy metals are required for the proper functioning of several metabolic pathways, their dysregulation can cause many cellular and molecular alterations, which can enhance the risks associated with several neurodegenerative diseases. For example, high levels of heavy metals like manganese (Mn) affect the central nervous system with implications in both higher-order cognitive and motor functions. In addition, the buildup of amyloid aggregates and metal ions in the brain of patients with Alzheimer's disease is associated with disease pathogenesis. Small molecules capable of targeting neuroinflammation and neuroprotection pathways would be valuable to elucidate the pathological pathways associated with metal toxicity in neurogenerative disease. This chapter will summarize the necessary steps involved in (1) culturing of cell lines and maintenance of animal models, (2) design and preparation of samples of small molecules and treatment methodologies, (3) RNA and protein isolation and preparation of tissue and cell culture samples for quantitative studies, and (4) quantitative estimation of cellular products.

Mini-review: Biological Movements as Objects of Natural Science

BACKGROUND: Two approaches to biological movement have dominated the field, the computational approach (internal models) and the approach based on laws of nature pioneered by several researchers including Michael Turvey. AIM AND METHOD: We review a body of literature exploring and expanding the approach based on laws of nature. We show, in particular, how this approach fits the philosophical traditions of Merleau-Ponty, the theory of control with spatial referent coordinates, the principle of abundance, and the concept of performance-stabilizing synergies using the uncontrolled manifold hypothesis. RESULTS: Currently, this scheme of motor control has been applied successfully in studies of a variety of effectors, from single motor units to the whole body, a variety of tasks, and various populations. It led to the discovery of new phenomena and new interpretations of known phenomena. It has been productive in studies of neurological patients offering new understanding of some of the common pathologies (e.g., spasticity) and new tools for early diagnosis of various subcortical disorders and monitoring treatment effects. CONCLUSION: Currently, this field faces a number of challenges including the following: Mapping steps in the hierarchical control scheme on neurophysiological structures and circuits, understanding the relative role of intra-muscle (spinal) and multi-effector (supraspinal) synergies, expanding studies of movements in intact animals and animal preparation, and moving beyond the current scheme to fields traditionally associated with psychology. Just like the current scheme represents moving “outside the box” of classical mechanics, a step outside the current thinking is needed.

Minimally invasive longitudinal intravital imaging of cellular dynamics in intact long bone.

Intravital two-photon microscopy enables deep-tissue imaging at high temporospatial resolution in live animals. However, the endosteal bone compartment and underlying bone marrow pose unique challenges to optical imaging as light is absorbed, scattered and dispersed by thick mineralized bone matrix and the adipose-rich bone marrow. Early bone intravital imaging methods exploited gaps in the cranial sutures to bypass the need to penetrate through cortical bone. More recently, investigators have developed invasive methods to thin the cortical bone or implant imaging windows to image cellular dynamics in weight-bearing long bones. Here, we provide a step-by-step procedure for the preparation of animals for minimally invasive, nondestructive, longitudinal intravital imaging of the murine tibia. This method involves the use of mixed bone marrow radiation chimeras to unambiguously double-label osteoclasts and osteomorphs. The tibia is exposed by a simple skin incision and an imaging chamber constructed using thermoconductive T-putty. Imaging sessions up to 12 h long can be repeated over multiple timepoints to provide a longitudinal time window into the endosteal and marrow niches. The approach can be used to investigate cellular dynamics in bone remodeling, cancer cell life cycle and hematopoiesis, as well as long-lived humoral and cellular immunity. The procedure requires an hour to complete and is suitable for users with minimal prior expertise in small animal surgery.

A Mouse Model of MHV-1 Virus Infection for Study of Acute and Long COVID Infection.

COVID-19, caused by SARS-CoV-2, has had a significant global impact. While vaccines and treatments have reduced severe cases and deaths, the long-term effects are not yet well understood. Current models used for research, such as non-human primates and transgenic mice, are expensive and require scarce Biosafety Level-3 (BSL-3) laboratories, thereby limiting their practicality. However, the mouse hepatitis virus 1 (MHV-1) mouse model offers a promising alternative. This surrogate model can be investigated in more widely available Biosafety Level-2 (BSL-2) laboratories. Furthermore, mice are affordable and easy to handle, and utilizing MHV-1 as a surrogate for SARS-CoV-2 eliminates the need for costly transgenic mice. Importantly, the MHV-1 model successfully recapitulates COVID-19-related clinical symptoms, weight loss, multiorgan pathological changes and failure in acute stages, irreversible neurological complications, and other long-term organ dysfunction post-infection, which are similar to available human data post-COVID-19. To assist researchers in establishing and using the MHV-1 mouse model, this protocol offers comprehensive guidance encompassing procedures for animal preparation, induction of viral infection, clinical observation, pathological changes, and tissue analysis for mechanistic studies, thereby yielding valuable insights into disease mechanisms and progression. By adopting the MHV-1 model and the provided protocols, researchers can effectively circumvent financial constraints and the limited availability of BSL-3 laboratories, thus facilitating a more accessible and cost-effective approach to investigating the underlying mechanisms of SARS-CoV-2 pathophysiology and exploring potential therapeutic interventions. © 2023 Wiley Periodicals LLC. Basic Protocol: Induction of mouse hepatitis virus 1 (MHV-1) infection in A/J mice Support Protocol 1: Histological evaluation Support Protocol 2: Liver enzyme measurement Support Protocol 3: Western blot analysis of aquaporin expression Support Protocol 4: mRNA measurement Support Protocol 5: Immunohistochemistry/immunofluorescence Support Protocol 6: Tissue water measurement.

NHS-POx-loaded patch versus fibrin sealant patch in a porcine robotic liver bleeding model

BackgroundThe management of bleeding is paramount to any surgical procedure. With the increased use of less invasive laparoscopic and robotic methods, achieving hemostasis can be challenging since the surgeons cannot manually apply hemostatic agents directly onto bleeding tissue. In this study, we assessed the use of a pliable hemostatic sealant patch comprising fibrous gelatin carrier impregnated with poly(2-oxazoline) (NHS-POx) for hemostasis in robotic liver resection in a porcine bleeding model.MethodsThe NHS-POx-loaded patch (GATT-Patch), was first evaluated in a Feasibility Study to treat surgical bleeding in 10 lesions, followed by a Comparative Study in which the NHS-POx patch was compared to a standard-of-care fibrin sealant patch (TachoSil), in 36 lesions (superficial, resection, or deep injuries mimicking metastasectomies). For each lesion type, the NHS-POx and fibrin sealant patches were used in an alternating fashion with 18 lesions treated with NHS-POx and 18 with the fibrin patch. Animal preparation and surgical procedures were consistent across studies. The primary outcome was time to hemostasis (TTH) within 3 min for the Feasibility Study and within 5 min for the Comparative Study.ResultsIn the Feasibility Study, 8 of the 10 NHS-POx-treated lesions achieved hemostasis at 30 s and 3 min. In the Comparative Study, all 18 NHS-POx patch-treated lesions and 9 of the 18 fibrin sealant patch-treated lesions achieved hemostasis at 5 min. Median TTH with NHS-POx vs fibrin sealant patch was 30 vs 300 s (P < 0.001).ConclusionsIn this animal study, hemostasis during robotic liver surgery was achieved faster and more often with the NHS-POx loaded vs fibrin sealant patch.

Exploring The Symbiotic Economic Benefits Between Farmers and Herders to Promote Peaceful Coexistence in Taraba State Nigeria

This paper explored the symbiotic economic benefits between farmers and herders in Taraba State to promote peaceful coexistence. Taraba State is one of the states in the North East region of Nigeria that is mainly affected by the farmers-herders crisis. The paper illustrated the causes of the farmers-herders crisis which include the growing population, abandonment of the grazing reserve system, and proliferation of small arms and light weapons among others. Although the Federal and State Governments have responded in several ways, among which the creation of grazing reserves in 1965, the establishment of the National Commission for Nomadic Education (NCNE) in 1989, the use of the Armed Forces to curb internal security caused by farmers-herders crisis, proposed National Grazing Reserve Bill 2016, proposed Cattle Ranching System 2018, legislation prohibiting open grazing and the Great Green Wall Agency of the Federal Government. All these efforts by the Federal Government and various State Governments could not bring the desired peaceful coexistence between farmers and herders. The crisis still lingered in Taraba State and many other states. Therefore, the paper explored the symbiotic economic benefits that could be enjoyed by farmers and herders leading to peaceful coexistence. Some of the symbiotic economic benefits capable of stimulating peaceful coexistence are; after harvesting crops on their farm, they usually allow cattle to graze on the leftovers, during which excrement from the cows provide manure for the farm, use of yam and cassava peels for preparation of animal feeds, use of rice, guinea corn, maize, and millet chaff for animal feeds and use of animal waste as fertilizer. The author concluded that exploring the symbiotic economic benefits explicated in this paper can bring about peaceful coexistence between farmers and herders which will also result in a peaceful Taraba State. It was suggested that government and private individuals should establish ranches within farming communities in such a manner that herders can get animal feeds from farmers while the farmers get manure from the herders’ farms.

Quality of hematology and clinical chemistry results in laboratory and zoo nonhuman primates: Effects of the preanalytical phase. A review.

Most errors in clinical pathology originate in the preanalytical phase, which includes all steps from the preparation of animals and equipment to the collection of the specimen and its management until analyzed. Blood is the most common specimen collected in nonhuman primates. Other specimens collected include urine, saliva, feces, and hair. The primary concern is the variability of blood hematology and biochemistry results due to sampling conditions with the effects of capture, restraint, and/or anesthesia. Housing and diet have fewer effects, with the exception of food restriction to reduce obesity. There has been less investigation regarding the impact of sampling conditions of nonblood specimens.

SULFORAPHANE ALLEVIATES POSTRESUSCITATION LUNG PYROPTOSIS POSSIBLY VIA ACTIVATING THE NRF2/HO-1 PATHWAY.

Introduction: Sulforaphane (SFN), known as the activator of the nuclear factor E2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway, has been proven to protect the lung against various pathological stimuli. The present study aimed to investigate the effect of SFN on lung injury induced by systemic ischemia reperfusion after cardiac arrest and resuscitation. Methods: After animal preparation, 24 pigs were randomly divided into sham group (n = 6), cardiopulmonary resuscitation group (CPR, n = 9), or CPR + SFN group (n = 9). The experimental model was then established by 10 min of cardiac arrest followed by 6 min of CPR. Once spontaneous circulation was achieved, a dose of 2 mg/kg of SFN diluted in 20 mL of saline was intravenously infused with a duration of 5 min. During 4 h of observation after resuscitation, extravascular lung water index (ELWI), pulmonary vascular permeability index (PVPI), and oxygenation index were regularly evaluated. At 24 h after resuscitation, lung tissues were harvested to evaluate the score of lung histopathological injury, the activity of superoxide dismutase, the contents of malondialdehyde, IL-1β, and IL-18, and the expression levels of NOD-like receptor pyrin domain 3, cleaved caspase 1, gasdermin D (GSDMD), GSDMD N-terminal, Nrf2, and HO-1. Results: During CPR, spontaneous circulation was achieved in six and seven pigs in the CPR and CPR + SFN groups, respectively. After resuscitation, the indicators of lung injury (ELWI, PVPI, and oxygenation index) were all better in the CPR + SFN group than in the CPR group, in which the differences in ELWI and PVPI at 2, and 4 h after resuscitation were significant between the two groups. In addition, SFN significantly reduced lung injury score, improved oxidative imbalance (superoxide dismutase, malondialdehyde), decreased pyroptosis-related proinflammatory cytokines (IL-1β, IL-18), downregulated pyroptosis-related proteins (NOD-like receptor pyrin domain 3, cleaved caspase 1, GSDMD, GSDMD N-terminal), and activated the Nrf2/HO-1 pathway when compared with the CPR group. Conclusion: SFN produced effective postresuscitation lung protection through alleviating lung pyroptosis possibly via activating the Nrf2/HO-1 pathway in pigs.

Differential reductions in the capillary red-blood-cell flux between retina and brain under chronic global hypoperfusion.

It has been hypothesized that abnormal microcirculation in the retina might predict the risk of ischemic damages in the brain. Direct comparison between the retinal and the cerebral microcirculation using similar animal preparation and under similar experimental conditions would help test this hypothesis. We investigated capillary red-blood-cell (RBC) flux changes under controlled conditions and bilateral-carotid-artery-stenosis (BCAS)-induced hypoperfusion, and then compared them with our previous measurements performed in the brain. We measured capillary RBC flux in mouse retina with two-photon microscopy using a fluorescence-labeled RBC-passage approach. Key physiological parameters were monitored during experiments to ensure stable physiology. We found that under the controlled conditions, capillary RBC flux in the retina was much higher than in the brain (i.e., cerebral cortical gray matter and subcortical white matter), and that BCAS induced a much larger decrease in capillary RBC flux in the retina than in the brain. We demonstrated a two-photon microscopy-based technique to efficiently measure capillary RBC flux in the retina. Since cerebral subcortical white matter often exhibits early pathological developments due to global hypoperfusion, our results suggest that retinal microcirculation may be utilized as an early marker of brain diseases involving global hypoperfusion.

Evaluation of proximate compositions and profiling of nutritional aspects in pupae of tasar silkworm Antheraea mylitta (Drury) as potential for food and feed resources

Aim: To investigate the proximate compositions, amino acids profile, phenols, flavonoids, fatty acids and minerals in Tasar silkworm pupae and assessment of biological potential of pupae extracts. Methodology: Biochemical composition such as proteins, fat, carbohydrate, chitin, ash, moisture and minerals were analyzed in Tasar silkworm pupae. The amino acid, vitamins, phenolics and flavonoid, fatty acids and free radical scavenging assay were evaluated. Results: The pupae powder contained 11.23% moisture, 60.67% crude protein, 23.83% fat, 3.29% carbohydrate, 5.1% ash and 3.87% chitin on a dry matter basis. Further, the pupae protein contained 19 amino acids, including all of the essential amino acids. Similarly, the pupae powder contained both water and fat soluble vitamins with higher content of tocopherol (13.23 µg 100 gm-1), phenolics compounds majorly ferulic acid (1317.5 µg gm-1) and p-coumaric acid (730.96 µg gm-1), flavonoids catechin (40.771 µg gm-1) and myricetin (12.466 µg gm-1) at higher levels and fatty acid with higher palmitic acid content (6.565 mg g-1). Mineral analysis indicated higher magnesium (208 mg 100 gm-1), calcium (47.79 mg 100gm-1) and iron (37.72 mg 100 gm-1) contents. Further, pupae extract exhibited free radical scavenging potential in a concentration-dependent manner. Interpretation: The results of the study indicate tasar pupae as a renewable and sustainable source for preparation of animal feeds. Key words: Antheraea mylitta, Antioxidants, Tasar pupae

Calcium Imaging in Mouse Superior Colliculus.

The superior colliculus (SC), an evolutionarily conserved midbrain structure in all vertebrates, is the most sophisticated visual center before the emergence of the cerebral cortex. It receives direct inputs from ~30 types of retinal ganglion cells (RGCs), with each encoding a specific visual feature. It remains elusive whether the SC simply inherits retinal features or if additional and potentially de novo processing occurs in the SC. To reveal the neural coding of visual information in the SC, we provide here a detailed protocol to optically record visual responses with two complementary methods in awake mice. One method uses two-photon microscopy to image calcium activity at single-cell resolution without ablating the overlaying cortex, while the other uses wide-field microscopy to image the whole SC of a mutant mouse whose cortex is largely undeveloped. This protocol details these two methods, including animal preparation, viral injection, headplate implantation, plug implantation, data acquisition, and data analysis. The representative results show that the two-photon calcium imaging reveals visually evoked neuronal responses at single-cell resolution, and the wide-field calcium imaging revealsneural activity across the entire SC. By combining these two methods, one can reveal the neural coding in the SC at different scales, and such combination can also be applied to other brain regions.

Rationale for the prevention of mastitis in cows during the dry period and after calving

Testing cows for mastitis before starting and treating all milch cows with a long-acting antimicrobial agent is an important component of the preventive preparation of animals for the dry period. In addition, determining the sensitivity of pathogens isolated on the farm and rotating antimicrobials increases the effectiveness of therapy and reduces the risk of resistant strains of microorganisms. The purpose of this study was to determine the preventive and therapeutic effects of preparations based on povidone-iodine and cefquinome sulfate for cows with mastitis. The following methods were used in the study: calculation of the total number of somatic cells by flow cytometry; California test; sensitivity to antimicrobial agents by agar disks; clinical and physiological method; statistical method. During the examination of cows for mastitis, it was identified that in the control group the number of somatic cells averaged 450 thousand/cm3, the total number of microorganisms was 130 thousand. In cows of the experimental group, productivity was 23.6%, the number of somatic cells was 600 thousand/cm3, microorganisms – 550 thousand CFU/cm3. It was identified that the isolated microflora showed high sensitivity to the preparation based on povidone-iodine and cefquinome sulfate. Therefore, udder conservation for cows of the experimental group with signs of mastitis was conducted with a product based on povidone-iodine, which affected the increase in lactation and improvement of milk quality after calving. The criteria for milk in the experimental group at the end of the experiment corresponded to the grade extra – 30%, top – 60%, and first – 10%. As a result of the therapy, lactation improved in cows, and the quality of milk corresponded to the first grade. At the end of the study, the quality of milk in cows of the control group corresponded to the extra Grade – 10%, top – 40%, and first – 50%. The practical value of the study lies in the prevention of mastitis on the farm, improving the quality of the resulting products, reducing the cost of veterinary care and culling animals

Estimating cochlear impulse responses using frequency sweeps.

Cochlear mechanics tends to be studied using single-location measurements of intracochlear vibrations in response to acoustical stimuli. Such measurements, due to their invasiveness and often the instability of the animal preparation, are difficult to accomplish and, thus, ideally require stimulus paradigms that are time efficient, flexible, and result in high resolution transfer functions. Here, a swept-sine method is adapted for recordings of basilar membrane impulse responses in mice. The frequency of the stimulus was exponentially swept from low to high (upward) or high to low (downward) at varying rates (from slow to fast) and intensities. The cochlear response to the swept-sine was then convolved with the time-reversed stimulus waveform to obtain first and higher order impulse responses. Slow sweeps of either direction produce cochlear first to third order transfer functions equivalent to those measured with pure tones. Fast upward sweeps, on the other hand, generate impulse responses that typically ring longer, as observed in responses obtained using clicks. The ringing of impulse response in mice was of relatively small amplitude and did not affect the magnitude spectra. It is concluded that swept-sine methods offer flexible and time-efficient alternatives to other approaches for recording cochlear impulse responses.

Evaluation of practices used to reduce the incidence of bovine respiratory disease in Australian feedlots (to November 2021).

Bovine respiratory disease (BRD) has been identified as the most significant infectious disease of feedlot cattle in eastern Australia.1 Bovine respiratory disease causes economic loss due to medication costs, mortalities, excessive feed inputs associated with increased time on feed, reduced sale prices and associated labour costs. Bovine respiratory disease is a complex multifactorial condition with multiple animal, environmental and management risk factors predisposing cattle to illness. A range of microorganisms are implicated in BRD with at least four viral and five bacterial species commonly involved individually or in combination. The viruses most commonly associated with BRD in Australia are bovine herpesvirus 1 (BHV1), bovine viral diarrhoea virus (BVDV or bovine pestivirus), bovine parainfluenza 3 virus (PI3) and bovine respiratory syncytial virus (BRSV). More recently, bovine coronavirus has been identified as a potential viral contributor to BRD in Australia.2 A number of bacterial species have also been recognised as important to the BRD complex; these include Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, Trueperella pyogenes and Mycoplasma bovis. Although one or more of the pathogens listed above can be isolated from clinical cases of BRD, there is no evidence that infection alone causes serious illness. This indicates that, in addition to specific infectious agents, other factors are crucial for the development of BRD under field conditions. These can be categorised as environmental, animal and management risk factors. These risk factors are likely to exert their effects through multiple pathways including reductions in systemic and possibly local immunity. For example, stressors such as weaning, handling at saleyards, transport, dehydration, weather conditions, dietary changes, comingling and pen competition might reduce the effectiveness of the immune system. Reduced immunocompetence can allow opportunistic infection of the lower airways with potential pathogens leading to the development of BRD. The objective of this paper is to critically review the evidence for management practices aimed at reducing the incidence of BRD in Australian feedlot cattle. Predisposing factors (Table 1) largely beyond the control of most feedlots, such as weather and exposure to respiratory viruses, are discussed separately, but these factors can generate indirect prevention responses that are discussed under the preventative practices categories. The current practices are classified as either animal preparation practices (Table 2) or feedlot management practices (Table 3).