Rabbit Kidney Research Articles

Ultrafast 3-D Transcutaneous Super Resolution Ultrasound Using Row-Column Array Specific Coherence-Based Beamforming and Rolling Acoustic Sub-aperture Processing: In Vitro, in Rabbit and in Human Study

ObjectiveThis study aimed to realise 3-D super-resolution ultrasound imaging transcutaneously with a row-column array which has far fewer independent electronic channels and a wider field of view than typical fully addressed 2-D matrix arrays. The in vivo image quality of the row-column array is generally poor, particularly when imaging non-invasively. This study aimed to develop a suite of image formation and post-processing methods to improve image quality and demonstrate the feasibility of ultrasound localisation microscopy using a row-column array, transcutaneously on a rabbit model and in a human. MethodsTo achieve this, a processing pipeline was developed which included a new type of rolling window image reconstruction, which integrated a row-column array specific coherence-based beamforming technique with acoustic sub-aperture processing. This and other processing steps reduced the ‘secondary’ lobe artefacts, and noise and increased the effective frame rate, thereby enabling ultrasound localisation images to be produced. ResultsUsing an in vitro cross tube, it was found that the procedure reduced the percentage of ‘false’ locations from ∼26% to ∼15% compared to orthogonal plane wave compounding. Additionally, it was found that the noise could be reduced by ∼7 dB and the effective frame rate was increased to over 4000 fps. In vivo, ultrasound localisation microscopy was used to produce images non-invasively of a rabbit kidney and a human thyroid. ConclusionIt has been demonstrated that the proposed methods using a row-column array can produce large field of view super-resolution microvascular images in vivo and in a human non-invasively.

Three-dimensional morphometry of kidney in New Zealand rabbit using unbiased design-based stereology.

The rabbit is widely used as a laboratory animal in experimental models of kidney diseases. This species is also important from a veterinary perspective as a companion animal. Stereology has been accepted as an accurate approach to kidney morphometry. The objective of the present project was to provide normal quantitative stereological parameters for adult rabbit kidneys. The left kidneys of five adult male New Zealand rabbits were used. Isotropic sections were obtained using the orientation method. Total kidney volume was calculated by the Cavalieri principle. The volume fraction of the renal structures was estimated using the point counting system. The lengths of the proximal convoluted tubule (PCT) and distal convoluted tubule (DCT) were calculated using counting frames. The total glomerular number was accounted for using the physical/fractionator technique. The mean glomerular volume was obtained by dividing the total volume of glomeruli by their total number. The total volume of rabbit kidneys calculated was 10.39 ± 1.98 cm3. The fractional volume of the kidney cortex and medulla accounted for 57.79 ± 0.65% and 42.2 ± 0.65%, respectively. The total glomerular volume was 2.18 ± 0.32% of the whole kidney. The total number of glomeruli in the rabbit kidney was estimated as 204.68 ± 12 × 103. The mean glomerular volume measured 1.07 ± 0.12 × 106 μm3. The total length of PCT and DCT was 2.96 ± 0.29 km and 1.38 ± 0.24 km, respectively. These findings can be used as a reference in experimental nephrology research and may help to expand the knowledge of nephrology in mammals by comparing with available data on humans and other species. RESEARCH HIGHLIGHTS: Three-dimensional morphometry of adult rabbit kidney structures was analyzed using quantitative stereology. Total volume of kidney, fractional volume of cortex and medulla, length of renal tubules and number of nephrons were estimated. These three-dimensional morphometrical data can be used as a reference in experimental nephrology research and may help to expand the knowledge of nephrology in mammals.

27 MHz constant field dielectric warming of kidneys cryopreserved by vitrification

Organs cryopreserved by vitrification are exposed to the lowest possible concentration of cryoprotectants for the least time necessary to successfully avoid ice formation. Faster cooling and warming rates enable lower concentrations and perfusion times, reducing toxicity. Since warming rates necessary to avoid ice formation during recovery from vitrification are typically faster than cooling rates necessary for vitrification, warming speed is a major determining factor for successful vitrification. Dielectric warming uses an oscillating electric field to directly heat water and cryoprotectant molecules inside organs to achieve warming that's faster and more uniform than can be achieved by heat conduction from the organ surface. This work studied 27 MHz dielectric warming of rabbit kidneys perfused with M22 vitrification solution. The 27 MHz frequency was chosen because its long wavelength and penetration depth are suitable for human organs, because it had an anticipated favorable temperature of maximum dielectric absorption in M22, and because it's an allocated frequency for industrial and amateur use with inexpensive amplifiers available. Previously vitrified kidneys were warmed from −100 °C by placement in a 27 MHz electric field formed between parallel capacitor plates in a resonant circuit. Power was varied during warming to maintain constant electric field amplitude between the plates. Maximum power absorption occurred near −70 °C, with a peak warming rate near 150 °C/min in 50 mL total volume with approximately 500 W power. After some optimization, it was possible to warm ∼13 g vitrified kidneys with unprecedentedly little injury from medullary ice formation and a favorable serum creatinine trend after transplant. Distinct behaviors of power absorption and system tuning observed as a function of temperature during warming are promising for non-invasive thermometry and future automated control of the warming process at even faster rates with user-defined temperature dependence.

Drinking magnetized water alters blood constituents, and structure of spleen and kidney in rabbits

This study aimed to investigate the effect of magnetic field on physicochemical properties of water and evaluating the effects of the magnetized water (MW ) on the productive performance, liver enzymes, spleen and kidney structure of rabbits. Water samples were collected to determine pH and electrical conductivity (EC), and water structure was investigated by Transmission Electron Microscopy (TEM). Twenty-four weaned Rex rabbits, 21 d old, were allotted into two experimental groups: the first group was assigned as control, received regular tap water (TW), and the treated group, received MW, for 5 weeks. Productive traits were recorded weekly and at the end of the experiment, blood samples, spleen and kidney were collected for examinations. Results showed that pH and EC of MW were higher than those of TW. In addition, the arrangement MW cluster showed a unique alteration on the nano-scale. Growth performance indicators were similar in both experimental treatments, except FCR of the MW rabbits was better than that of the TW rabbits. The MW had no significant effect on plasma concentration of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and creatinine in growing Rex rabbits received MW in comparison with those received regular TW. Spleen histological structure of rabbits of both groups was normal. However, the epithelial cells lining renal tubules of kidneys of rabbits in MW group appeared large with basophilic nuclei in comparison with TW group. Conclusively, magnetic field alters the physicochemical properties of water. The MW may consequently increase blood glucose level and spleen weight % and enhance kidney structure in growing rabbits. Moreover, more studies are still needed to know the benefits of providing the magnetized water to ‎animals. ‎

Hyperoside inhibits EHV-8 infection via alleviating oxidative stress and IFN production through activating JNK/Keap1/Nrf2/HO-1 signaling pathways.

Equine herpesvirus type 8 (EHV-8) causes abortion and respiratory disease in horses and donkeys, leading to serious economic losses in the global equine industry. Currently, there is no effective vaccine or drug against EHV-8 infection, underscoring the need for a novel antiviral drug to prevent EHV-8-induced latent infection and decrease the pathogenicity of this virus. The present study demonstrated that hyperoside can exert antiviral effects against EHV-8 infection in RK-13 (rabbit kidney cells), MDBK (Madin-Darby bovine kidney), and NBL-6 cells (E. Derm cells). Mechanistic investigations revealed that hyperoside induces heme oxygenase-1 expression by activating the c-Jun N-terminal kinase/nuclear factor erythroid-2-related factor 2/Kelch-like ECH-associated protein 1 axis, alleviating oxidative stress and triggering a downstream antiviral interferon response. Accordingly, hyperoside inhibits EHV-8 infection. Meanwhile, hyperoside can also mitigate EHV-8-induced injury in the lungs of infected mice. These results indicate that hyperoside may serve as a novel antiviral agent against EHV-8 infection.IMPORTANCEHyperoside has been reported to suppress viral infections, including herpesvirus, hepatitis B virus, infectious bronchitis virus, and severe acute respiratory syndrome coronavirus 2 infection. However, its mechanism of action against equine herpesvirus type 8 (EHV-8) is currently unknown. Here, we demonstrated that hyperoside significantly inhibits EHV-8 adsorption and internalization in susceptible cells. This process induces HO-1 expression via c-Jun N-terminal kinase/nuclear factor erythroid-2-related factor 2/Kelch-like ECH-associated protein 1 axis activation, alleviating oxidative stress and triggering an antiviral interferon response. These findings indicate that hyperoside could be very effective as a drug against EHV-8.

In vitro assay to determine inactivation of Toxoplasma gondii in meat samples

Consumption of raw and undercooked meat is considered as an important source of Toxoplasma gondii infections. However, most non-heated meat products contain salt and additives, which affect T. gondii viability. It was our aim to develop an in vitro method to substitute the mouse bioassay for determining the effect of salting on T. gondii viability. Two sheep were experimentally infected by oral inoculation with 6.5 × 104 oocysts. Grinded meat samples of 50 g were prepared from heart, diaphragm, and four meat cuts. Also, pooled meat samples were either kept untreated (positive control), frozen (negative control) or supplemented with 0.6 %, 0.9 %, 1.2 % or 2.7 % NaCl. All samples were digested in pepsin-HCl solution, and digests were inoculated in duplicate onto monolayers of RK13 (a rabbit kidney cell line). Cells were maintained for up to four weeks and parasite growth was monitored by assessing Cq-values using the T. gondii qPCR on cell culture supernatant in intervals of one week and ΔCq-values determined. Additionally, 500 μL of each digest from the individual meat cuts, heart and diaphragm were inoculated in duplicate in IFNγ KO mice. Both sheep developed an antibody response and tissue samples contained similar concentrations of T. gondii DNA. From all untreated meat samples positive ΔCq-values were obtained in the in vitro assay, indicating presence and multiplication of viable parasites. This was in line with the mouse bioassay, with the exception of a negative mouse bioassay on one heart sample. Samples supplemented with 0.6 %–1.2 % NaCl showed positive ΔCq-values over time. The frozen sample and the sample supplemented with 2.7 % NaCl remained qPCR positive but with high Cq-values, which indicated no growth. In conclusion, the in vitro method has successfully been used to detect viable T. gondii in tissues of experimentally infected sheep, and a clear difference in T. gondii viability was observed between the samples supplemented with 2.7 % NaCl and those with 1.2 % NaCl or less.

ACUTE AND SUB-CHRONIC TOXICITY ASSESSMENT OF PYRIDOSTIGMINE BROMIDE 90 MG EXTENDED- ELEASE TABLETS IN EXPERIMENTAL ANIMALS

Purpose: This study aimed to assess the acute and subchronic toxicity of Pyridostigmine bromide 90 mg extended-release tablets in experimental animals. Subjects and methods: Pyridostigmine bromide 90 mg extended-release tablets were prepared complying in-house specifications. Acute oral toxicity (LD50) was determined in white mice using the Litchfield-Wilcoxon method. Subchronic toxicity was assessed in rabbits following OECD guidelines. Results: The acute toxicity study revealed an LD50 of 17.9 mg/kg when Pyridostigmine bromide 90 mg extended-release tablets were orally administered to mice. In the subchronic toxicity assessment, rabbits were treated with Pyridostigmine bromide tablets for 28 days. Doses of 7.2 mg/kg/day and 21.6 mg/kg/day showed no significant alterations in hematological parameters (red blood cells, hemoglobin, hematocrit, mean corpuscular volume, white blood cells, platelets), blood biochemical parameters (AST, ALT, total protein, creatinine, urea), and did not cause damage to the histopathology of the liver, spleen, and kidneys in rabbits. However, the dose of 21.6 mg/kg/day resulted in a statistically significant difference in rabbit weight gain compared to those administered a dose of 7.2 mg/kg/day and those in the control group.

Cumin Extract Alters The Histology of Kidney and Duodenum in Adult Rabbit

Background: The current study determined the histological alterations of the kidney and duodenum due to the administration of the cumin plant. The objective of the study was how consuming cumin affects the histological structure of the kidney and duodenum. Methods: Ten healthy male rabbits were divided into two groups of five each. They were housed in the animal facility at the College of Veterinary Medicine, Kerbala University. The treatment group received an oral dose of cumin extract at 250 mg/kg body weight once daily for six weeks, while the control group was given a standard diet and water. Hematoxylin and eosin staining was used to examine tissue samples from the kidneys and duodenum. Results: The histological analysis revealed significant changes in the kidney and duodenum tissues of the rabbits treated with cumin extract. In the kidneys, there was an increase in the diameter of glomeruli and a narrower lumen of the proximal tubules, indicating increased activity. Similarly, the duodenum of the treated group exhibited taller villi and deeper crypts, suggesting enhanced absorption activity. Moreover, the arrangement of tall columnar epithelial cells in the duodenal villi was altered. Conclusion: In conclusion, high intake of cumin extract showed various histological alterations in the urinary and digestive systems, particularly in the kidney and duodenum. These findings provided insights into the potential effects of cumin consumption on organ structure and function, highlighting the need for further research to understand its implications for human health better.

Broad Elevation Projection Super-Resolution Ultrasound (BEP-SRUS) Imaging With a 1-D Unfocused Linear Array.

Super-resolution ultrasound (SRUS) through localizing spatially isolated microbubbles (MBs) has been demonstrated to overcome the wave diffraction limit and reveal the microvascular structure and flow information at the microscopic scale. However, 3-D SRUS imaging remains a challenge due to the fabrication and computational complexity of 2-D matrix array probes. Inspired by X-ray radiography which can present information within a volume in a single projection image with much simpler hardware than X-ray computerized tomography (CT), this study investigates the feasibility of broad elevation projection super-resolution (BEP-SR) ultrasound using a 1-D unfocused linear array. Both simulation and in vitro experiments were conducted on 3-D microvessel phantoms. In vivo demonstration was done on the Rabbit kidney. Data from a 1-D linear array with and without an elevational focus were synthesized by summing up row signals acquired from a 2-D matrix array with and without delays. A full 3-D reconstruction was also generated as the reference, using the same data of the 2-D matrix array but without summing row signals. Results show that using an unfocused 1-D array probe, BEP-SR can capture significantly more information within a volume in both vascular structure and flow velocity than the conventional 1-D elevational-focused probe. Compared with the 2-D projection image of the full 3-D SRUS results using the 2-D array probe with the same aperture size, the 2-D projection SRUS image of BEP-SR has similar volume coverage, using 32 folds fewer independent elements. This study demonstrates BEP-SR's ability of high-resolution imaging of microvascular structures and flow velocity within a 3-D volume at significantly reduced costs. The proposed BEP method could significantly benefit the clinical translation of the SRUS imaging technique by making it more affordable and repeatable.

Apoptosis activation during Lagovirus europaeus/GI.2 infection in rabbits

Rabbit Haemorrhagic Disease (RHD) is a severe disease caused by Lagovirus europaeus/GI.1 and GI.2. Immunological processes such as apoptosis are important factors involved in the pathogenesis of Rabbit Haemorrhagic Disease (RHD). The process of programmed cell death has been quite well characterized in infection with GI.1 strains, but apoptosis in infection with GI.2 strains has not been widely studied. This is particularly important as several studies have shown that significant differences in the host immune response are observed during infection with different strains of Lagovirus europaeus. In this study, we analyzed the gene expression, protein levels and activity of key apoptotic cell death factors in the spleen, kidney, lung, and heart of rabbits. As a result, we showed that there is a significant increase in caspase-3, Bax, Bcl2 and Bax/Bcl2 mRNA gene expression ratio in organs of infected animals. Our results show also increased levels of cleaved caspase-3, caspase-6 and PARP. Moreover, significant activity of caspase-3 was also detected. Our results indicate that caspase-3, caspase-6 and genes coding Bcl2 family proteins play a key role in the apoptotic response in Lagovirus europaeus/GI.2 infection in organs that are not the target of virus replication.

Injectable Self-Expanding/Self-Propelling Hydrogel Adhesive with Procoagulant Activity and Rapid Gelation for Lethal Massive Hemorrhage Management.

Developing hydrogels that can quickly reach deep bleeding sites, adhere to wounds, and expand to stop lethal and/or noncompressible bleeding in civil and battlefield environments remains a challenge. Herein, an injectable, antibacterial, self-expanding, and self-propelling hydrogel bioadhesive with procoagulant activity and rapid gelation is reported. This hydrogel combines spontaneous gas foaming and rapid Schiff base crosslinking for lethal massive hemorrhage. Hydrogels have rapid gelation and expansion rate, high self-expanding ratio, excellent antibacterial activity, antioxidant efficiency, and tissue adhesion capacity. In addition, hydrogels have good cytocompatibility, procoagulant ability, and higher blood cell/platelet adhesion activity than commercial combat gauze and gelatin sponge. The optimized hydrogel (OD-C/QGQL-A30) exhibits better hemostatic ability than combat gauze and gelatin sponge in rat liver and femoral artery bleeding models, rabbit volumetric liver loss massive bleeding models with/without anticoagulant, and rabbit liver and kidney incision bleeding models with bleeding site not visible. Especially, OD-C/QGQL-A30 rapidly stops the bleedings from pelvic area of rabbit, and swine subclavian artery vein transection. Furthermore, OD-C/QGQL-A30 has biodegradability and biocompatibility, and accelerates Methicillin-resistant S. aureus (MRSA)-infected skin wound healing. This injectable, antibacterial, self-expanding, and self-propelling hydrogel opens up a new avenue to develop hemostats for lethal massive bleeding, abdominal organ bleeding, and bleeding from coagulation lesions.

Dual green hemostatic sponges constructed by collagen fibers disintegrated from Halocynthia roretzi by a shortcut method

Recently, biomacromolecules have received considerable attention in hemostatic materials. Collagen, an ideal candidate for hemostatic sponges due to its involvement in the clotting process, has been facing challenges in extraction from raw materials, which is time-consuming, expensive, and limited by cultural and religious restrictions associated with traditional livestock and poultry sources. To address these issues, this study explored a new shortcut method that using wild Halocynthia roretzi (HR), a marine fouling organism, as a raw material for developing HR collagen fiber sponge (HRCFs), which employed urea to disrupt hydrogen bonds between collagen fiber aggregates. This method simplifies traditional complex manufacturing processes while utilized marine waste, thus achieving dual green in terms of raw materials and manufacturing processes. FTIR results confirmed that the natural triple-helical structure of collagen was preserved. HRCFs exhibit a blood absorption ratio of 2000–3500 %, attributed to their microporous structure, as demonstrated by kinetic studies following a capillary model. Remarkably, the cytotoxicity and hemolysis ratio of HRCFs are negligible. Furthermore, during in vivo hemostasis tests using rabbit ear and kidney models, HRCFs significantly reduce blood loss and shorten hemostasis time compared to commercial gelatin sponge and gauze, benefiting from the capillary effect and collagen's coagulation activity. This study provides new insights into the design of collagen-based hemostatic biomaterials, especially in terms of both raw material and green manufacturing processes.

Dynamics of morphofunctional parameters in experimental pseudomonosis of rabbits

Among the most frequently reported diseases of rabbits, the main place is occupied by diseases of bacterial etiology, the pathogens of which are characterized by multidrug resistance. The aim of the study was to analyze the dynamics of morphometric indicators during experimental infection of rabbits with Pseudomonas aeruginosa bacteria. When assessing colonization resistance of organs, the following indicators were taken into account: colonization index, ratio of the number of microorganisms isolated from nasal cavity washes, contents of cecum of clinically healthy and sick animals. Significant changes in morphological parameters (p 0.05) were revealed during the isolation of P. aeruginosa from blood, lymph nodes, spleen, liver, and kidneys of sick rabbits. Overgrowth of isolates producing adhesive antigens, hemolysins, bacteriocins should be considered as prognostic markers of connective tissue dysplasia. The initiation, development, and outcome of microbial overgrowth syndrome are mediated by morphofunctional changes in compensatory mechanisms of mucociliary clearance system and colonization resistance.

SeMet alleviates AFB1-induced oxidative stress and apoptosis in rabbit kidney by regulating Nrf2//Keap1/NQO1 and PI3K/AKT signaling pathways

The purpose of this study was to explore the protective effect of SeMet on renal injury induced by AFB1 in rabbits and its molecular mechanism. Forty rabbits of 35 days old were randomly divided into control group, AFB1 group (0.3 mg AFB1/kg b.w), 0.2 mg/kg Se + AFB1 group (0.3 mg AFB1/kg b.w + 0.2 mg SeMet/kg feed) and 0.4 mg/kg Se + AFB1 group (0.3 mg AFB1/kg b.w + 0.4 mg SeMet/kg feed). The SeMet treatment group was fed different doses of SeMet diets every day for 21 days. On the 17–21 day, the AFB1 treatment group, the 0.2 mg/kg Se + AFB1 group and the 0.4 mg/kg Se + AFB1 group were administered 0.3 mg AFB1 /kg b.w by gavage (dissolved in 0.5 ml olive oil) respectively. The results showed that AFB1 poisoning resulted in the changes of renal structure, the increase of renal coefficient and serum biochemical indexes, the ascent of ROS and MDA levels, the descent of antioxidant enzyme activity, and the significant down-regulation of Nrf2, HO-1 and NQO1. Besides, AFB1 poisoning increased the number of renal apoptotic cells, rised the levels of PTEN, Bax, Caspase-3 and Caspase-9, and decreased the levels of PI3K, AKT, p-AKT and Bcl-2. In summary, SeMet was added to alleviate the oxidative stress injury and apoptosis of kidney induced by AFB1, and the effect of 0.2 mg/kg Se + AFB1 is better than 0.4 mg/kg Se + AFB1.

High-speed adaptive photoacoustic microscopy

Optical-resolution photoacoustic microscopy (OR-PAM) is capable of observing the distribution of optical absorbers inside bio-tissues with a high spatial resolution of micrometers. Unfortunately, due to the employment of a tight optical focus, it suffers from a limited depth of field (DOF), making it challenging to achieve high-resolution imaging of targets with arbitrary surfaces. Here, we propose a high spatiotemporal adaptive photoacoustic focusing mechanism through integrating a high-speed optical focuser, a time-of-flight contour deriving algorithm, and the rotary-scanning photoacoustic microscopy. The developed system, named high-speed adaptive photoacoustic microscopy (HA-PAM), features an ultrashort focus-shifting time of 5 ms and an enlarged DOF of up to 5 mm. With the assistance of the proposed mechanism, we can achieve a homogeneous lateral resolution of 6 μm over a 10 mm circular imaging domain within 5 s. We demonstrate the advantages of HA-PAM through imaging phantoms with curved surfaces, subcutaneous tumor-bearing mice, resected rabbit kidneys, and pulsating mouse brains. The imaging results suggest that this approach provides a high and consistent spatial resolution for imaging bio-tissues with arbitrary surfaces without sacrificing the imaging speed, and has the potential to extend the fundamental and clinical applications of OR-PAM.

Effect of yogurt on fluoride induced toxicity of plasma markers of kidney in rabbits

Fluoride (F) is one of the major chemical substances that damage the renal tissue prevention tubular reabsorption, increasing the excretion of sodium (Na+) and chloride (cl-), and enhancing creatinine (Cr), uric acid (UA), blood urea nitrogen (BUN) and potassium (K+) level. Results revealed that on 16th day in groups B, D, E and G, Cr. values were significantly (P˂0.05) increased on 31st day in group-F, Cr. value was significantly (P˂0.05) decreased, whereas, in groups-B, D, E and G, Cr. values were significantly increased (P˂0.05). On 16th and 31st day, in yogurt-treated groups i.e.- C and F, UA values were significantly (P˂0.05) decreased, whereas, in groups B, D, E and G, UA values were significantly (P˂0.05) increased. On 16th and 31st day, in groups-B, D, E and G BUN level was significantly (P˂0.05) increased. On 16th and 31st day in groups-B and E, Na+ level was significantly (P˂0.05) decreased. Whereas, in groups C, D, F and G, Na+ level was significantly (P˂0.05) increased. Likewise, on 16th and 31st day, in groups-B, D, E and G, K+ level was significantly (P˂0.05) increased. On 16th day in groups-B and E, cl- level was significantly (P˂0.05) decreased. While, in groups- F and G cl- level was significantly (P˂0.05) increased. On 31st in groups-B & E, cl- level was significantly (P˂0.05) decreased. While, in groups-C, D, F and G, cl- levels was significantly (P˂0.05) increased. It has been concluded that increased levels of sCr, UA, BUN, K+ and reduced levels of Na+ and cl- were observed in all fluoride treated groups. Yogurt-treated groups showed decreased levels of Cr, UA, BUN and K+ and increased levels of Na+ and Cl- in experimental rabbits

Fast 3D Super-Resolution Ultrasound With Adaptive Weight-Based Beamforming.

Super-resolution ultrasound (SRUS) imaging through localising and tracking sparse microbubbles has been shown to reveal microvascular structure and flow beyond the wave diffraction limit. Most SRUS studies use standard delay and sum (DAS) beamforming, where high side lobes and broad main lobes make isolation and localisation of densely distributed bubbles challenging, particularly in 3D due to the typically small aperture of matrix array probes. This study aimed to improve 3D SRUS by implementing a new fast 3D coherence beamformer based on channel signal variance. Two additional fast coherence beamformers, that have been implemented in 2D were implemented in 3D for the first time as comparison: a nonlinear beamformer with p-th root compression and a coherence factor beamformer. The 3D coherence beamformers, together with DAS, were compared in computer simulation, on a microflow phantom and in vivo. Simulation results demonstrated that all three adaptive weight-based beamformers can narrow the main lobe, suppress the side lobes, while maintaining the weaker scatter signals. Improved 3D SRUS images of microflow phantom and a rabbit kidney within a 3-second acquisition were obtained using the adaptive weight-based beamformers, when compared with DAS. The adaptive weight-based 3D beamformers can improve the SRUS and the proposed variance-based beamformer performs best in simulations and experiments. Fast 3D SRUS would significantly enhance the potential utility of this emerging imaging modality in a broad range of biomedical applications.

Digital PCR (dPCR) Quantification of miR-155-5p as a Potential Candidate for a Tissue Biomarker of Inflammation in Rabbits Infected with Lagovirus europaeus/Rabbit Hemorrhagic Disease Virus (RHDV)

MicroRNAs (miRNAs, miRs) are a group of small, 17–25 nucleotide, non-coding RNA sequences that, in their mature form, regulate gene expression at the post-transcriptional level. They participate in many physiological and pathological processes in both humans and animals. One such process is viral infection, in which miR-155 participates in innate and adaptive immune responses to a broad range of inflammatory mediators. Recently, the study of microRNA has become an interesting field of research as a potential candidate for biomarkers for various processes and disease. To use miRNAs as potential biomarkers of inflammation in viral diseases of animals and humans, it is necessary to improve their detection and quantification. In a previous study, using reverse transcription real-time quantitative PCR (RT-qPCR), we showed that the expression of ocu-miR-155-5p in liver tissue was significantly higher in rabbits infected with Lagovirus europaeus/Rabbit Hemorrhagic Disease Virus (RHDV) compared to healthy rabbits. The results indicated a role for ocu-miR-155-5p in Lagovirus europaeus/RHDV infection and reflected hepatitis and the impairment/dysfunction of this organ during RHD. MiR-155-5p was, therefore, hypothesized as a potential candidate for a tissue biomarker of inflammation and examined in tissues in Lagovirus europaeus/RHDV infection by dPCR. The objective of the study is the absolute quantification of ocu-miR-155-5p in four tissues (liver, lung, kidney, and spleen) of rabbits infected with Lagovirus europaeus/RHDV by digital PCR, a robust technique for the precise and direct quantification of small amounts of nucleic acids, including miRNAs, without standard curves and external references. The average copy number/µL (copies/µL) of ocu-miRNA-155-5p in rabbits infected with Lagovirus europaeus GI.1a/Rossi in the liver tissue was 12.26 ± 0.14, that in the lung tissue was 48.90 ± 9.23, that in the kidney tissue was 16.92 ± 2.89, and that in the spleen was 25.10 ± 0.90. In contrast, in the tissues of healthy control rabbits, the average number of copies/µL of ocu-miRNA-155-5p was 5.07 ± 1.10 for the liver, 23.52 ± 2.77 for lungs, 8.10 ± 0.86 for kidneys, and 42.12 ± 3.68 for the spleen. The increased expression of ocu-miRNA-155-5p in infected rabbits was demonstrated in the liver (a fold-change of 2.4, p-value = 0.0003), lung (a fold-change of 2.1, p-value = 0.03), and kidneys (a fold-change of 2.1, p-value = 0.01), with a decrease in the spleen (a fold-change of 0.6, p-value = 0.002). In the study of Lagovirus europaeus/RHDV infection and in the context of viral infections, this is the first report that shows the potential use of dPCR for the sensitive and absolute quantification of microRNA-155-5p in tissues during viral infection. We think miR-155-5p may be a potential candidate for a tissue biomarker of inflammation with Lagovirus europaeus/RHDV infection. Our report presents a new path in discovering potential candidates for the tissue biomarkers of inflammation.

Challenges and solution approaches for an improved assessment of reproductive toxicity ‐ species differences and in silica predictions

Within toxicology, reproductive toxicology is a highly relevant and socially particularly sensitive field. It encompasses all toxicological processes within the reproductive cycle and therefore includes many effects and modes of action. This makes the assessment of reproductive toxicity very challenging despite the established in vivo studies. In addition, the in vivo studies are very demanding both in terms of their conduct and interpretation, and there is scope for decision‐making on both aspects. As a result, the interpretation of study results may vary from laboratory to laboratory. For the final classification, the assessment of relevance for men is decisive. The problem here is that relatively little is known about the species differences between men and the usual test animals (rat and rabbit). The rabbit in particular has hardly been researched in molecular biology. The aim of the dissertation was to develop approaches for a better assessment of reproductive toxicity, with two different foci:The first aim was to investigate species differences, focusing on the expression of xenobiotic transporters during ontogeny. Xenobiotic transporters, of the superfamily of ATP‐binding cassette transporters (ABC) or solute carriers (SLC), are known to transport exogenous substances in addition to their endogenous substrates and therefore play an important role in the absorption, distribution and excretion of xenobiotics. Species differences in kinetics can in turn have a major impact on toxic effects. In the study, the expression of 20 xenobiotic transporters during ontogeny was investigated at the mRNA level in the liver, kidney and placenta of rats and rabbits and compared with that of men. This revealed major differences in the expression of the transporters between the species. However, further studies on the functionality and activity of the xenobiotic transporters are needed to fully assess the kinetic impact of the observed species differences. Overall, the study provides a valid starting point for further systematic investigations of species differences at the protein level. Furthermore, it provides previously unavailable data on the expression of xenobiotic transporters during ontogeny in rabbits, which is an important step in the molecular biological study of this species. The second part focused on investigating the predictive power of in silico models for reproductive toxicology in relation to pesticides. Both the commercial and the freely available models did not perform adequately in the evaluation. Three reasons could be identified for this: 1. many pesticides are outside the chemical space of the models, 2. different definition/assessment of reproductive toxicity and 3. problems in detecting similarity between molecules. To solve these problems, an extension of the databases on reproductive toxicity in relation to pesticides, respecting a uniform nomenclature, is needed. Furthermore, endpoint‐specific models should be developed which, in addition to the usual structure‐based fingerprints, use descriptors for, for example, biological activity. Overall, the dissertation shows how essential it is to further research the modes of action of reproductive toxicity. This knowledge is necessary to correctly assess in vivo studies and their relevance to men, as well as to improve the predictive power of in silico models by incorporating this information.

Robert Tigerstedt and the Discovery of Renin.

The year 2022 marks the 125th anniversary of the discovery of the first element of the renin-angiotensin-aldosterone system. The importance of this event on the further development of nephrology, cardiology, and endocrinology left us compelled to reminisce about it and its main author, Robert Tigerstedt (1853-1923), who was one of Scandinavia's most famous scientists. He studied medicine at the University of Helsinki, Finland. His doctoral dissertation On the Mechanical Stimulation of the Nervous System and 10 other original publications made him famous among the neurophysiological community. From 1881, he worked in the Physiology Department at Karolinska Institute, Stockholm, where he created a modern laboratory and became a professor at age 33 years. After meeting Carl Ludwig in Leipzig, he became interested in central blood circulation. In 1886, with Per Bergman, he started a series meticulously performed experiments with extracts of the rabbit kidney cortex, which, when injected into other rabbits, increased their blood pressure. The hypothetical responsible substance was called renin. The results were presented at the International Congress of Medicine in Moscow in 1887. Forty years later, Harry Goldblatt confirmed Tigerstedt's theory that "the substance which comes from kidneys increases the blood pressure." After he returned to Finland in 1901, Tigerstedt headed the Physiology Institute in Helsinki. His further activities included scientific work, teaching, and socially oriented issues like healthy nutrition and conditions in prison camps. He was also interested in the history of medicine and was a member of the Nobel Committee. His Textbook of Human Physiology was published in numerous editions in many languages. He also authored the renowned Textbook of Physiological Methodology and Physiology of Circulation. Tigerstedt published over 200 scientific papers and was an honorary doctor at many universities. He was known for his strong personality, critical judgment, idealism, humor, and warm heart.