ABSTRACT Purpose: As clinical liver perfusion systems use portal vein and artery flow, dual perfusion techniques are required even in small animal models in order to reproduce clinical setting. The aim of this study was to construct a new dual-flow perfusion system in rat model and optimized the oxygen supply to ensure the aerobic metabolization. Methods: The dual-flow circuit was fabricated using rat liver and whole blood samples as perfusates. The oxygen supply was controlled according to the amount of dissolved oxygen in the perfusate. Perfusate parameters and adenosine triphosphate (ATP) levels were analyzed to evaluate organ function and metabolic energy state. Stored whole blood also tested the suitability as perfusate. Results: Stored blood showed decrease oxygen delivery and liver function compared to fresh blood. Using fresh blood as perfusate with air only, the dissolved oxygen levels remained low and anaerobic metabolism increased. In contrast, with oxygen control at living body level, anaerobic metabolism was well suppressed, and tissue ATP content was increased. Conclusions: We developed a new dual-flow system that enable to reproduce the clinical settings. The perfusion system showed the possibility to improve the energy metabolic state of the perfused organ under appropriate partial pressure of oxygen. Purpose flow setting dualflow metabolization Methods perfusates (ATP Results only increased contrast level suppressed Conclusions settings

ABSTRACT Purpose Although transplanting two kidneys from a single donor to two recipients has some advantages, the right and left kidneys are not anatomically identical; thus, a surgical procedure considering the anatomical features of the donor kidneys is needed when transplanting them into the opposite renal fossae. Based on vast experience, the surgical details of pig orthotopic kidney transplantation from one donor to two recipients was reported. Methods When the right kidney was transplanted to the left renal fossa, the graft was inverted upside down, not backwards, thus ensuring that the anteroposterior relationship of the renal vessels was maintained and anatomically natural vascular anastomosis could be performed. Results Using this technique, we could have developed a pig experimental model that is safe and has a high success rate, even for researchers in the middle of their training. This technique of inverting the graft upside down was reported in human kidney transplantation to make vascular anastomosis easier. Conclusions In pig orthotopic kidney transplantation from one donor to two recipients, an anatomically natural vascular anastomosis could be performed via inverted grafting when the right kidney was transplanted into the left renal fossa.

ABSTRACT Purpose: This study aimed to develop a microsurgical technique to transplant extremely fragile renal organoids in vivo, created by in-vitro reaggregation of metanephros from fetal mice. These organoids in reaggregation and development were examined histologically after transplantation under the renal capsule. Methods: Initially, metanephros from fetal mice were enzymatically treated to form single cells, and spheroids were generated in vitro. Under a microscope, the renal capsule was detached to avoid bleeding, and the outer cylinder of the indwelling needle was inserted to detach the renal parenchyma from the renal capsule using water pressure. The reaggregated spheroid was aspirated from the culture plate using a syringe with an indwelling needle outer cylinder and carefully extruded under the capsule. Pathological analysis was performed to evaluate changes in reaggregated spheroids over time and the effects of co-culture of spinal cord and subcapsular implantation on maturation. Results: In vitro, the formation of luminal structures became clearer on day 5. These fragile organoids were successfully implanted without tissue crapes under the renal capsule and formed glomerular. The effect of spinal cord co-transplant was not obvious histrionically. Conclusions: A simple and easy method to transplant fragile spheroids and renal under the renal capsule without damage was developed.

ABSTRACT Purpose As a classical xenotransplantation model, porcine kidneys have been transplanted into the lower abdomen of non-human primates. However, we have improved upon this model by using size-matched grafting in the orthotopic position. The beneficial aspects and surgical details of our method are reported herein. Methods Donors were two newborn pigs (weighting 5 to 6 kg) and recipients were two cynomolgus monkeys (weighting, approximately, 7 kg). After bilateral nephrectomy, kidneys were cold-transported in Euro-Collins solution. The porcine kidney was transplanted to the site of a left nephrectomy and fixed to the peritoneum. Results Kidneys transplanted to the lower abdomen by the conventional method were more susceptible to torsion of the renal vein (two cases). In contrast, early-stage blood flow insufficiency did not occur in orthotopic transplants of theleft kidney. Conclusions Size-matched porcine-primate renal grafting using our method of transplanting tothe natural position of the kidneys contributes to stable post-transplant blood flow to the kidney.

Abstract Infectious viruses pose a threat to all living organisms, including humans, and can cause significant morbidity. Previous experience with pigs in medical education and research, rather than in domestic control settings, has led to a unique perspective on viral infections in swine. In this article, common porcine infectious diseases have been listed, based mainly on the authors’ experience thus far. For example, young domestic pigs that were used in surgical training and infected with hepatitis E were subjected to quarantine and isolation treatment, and attempts were made to develop a DNA vaccine for swine influenza arising from swine-to-human transmission. More recent research has focused on preventing infection by the African swine virus, a current threat. We hope that this article of porcine infectious diseases identified at the School of Medicine will help develop a breakthrough with regard to coronavirus disease.

Abstract Purpose: To modify a surgical catheterization method using the bent needle introducer in small animals. Methods: Eight-week-old male Lewis rats were used in the study. A needle introducer was created by bending a 21G injection needle at 45°. The bent needle introducer was used for catheter insertion into the left femoral artery of the rats under anesthesia. As a control, a catheter was directly inserted into the blood vessel without the introducer. The insertion time of each method was measured. Blood pressure and heart rate were measured 24 h after catheter insertion using the telemetry system. Results: Using the introducer, the catheter was successfully inserted within a short time in all rats. Without the introducer, a longer duration was required for catheter insertion. The frequency of the insertion with no catheter-based errors with the introducer tended to be higher than that without the introducer. The mean arterial pressure and heart rate 24 h after catheter insertion in each group were almost the same. Conclusions: We developed a surgical catheterization method using the introducer in small animals. This could potentially reduce the frequency of the insertion with catheter-based errors and insertion time.

Abstract Medicine can be broadly divided into two fields: clinical medicine that aims to save existing patients and basic medical research that aims to save the lives of future patients. In terms of disseminating basic medical research, medical journals play a vital role for physicians and scientists, as they enable them to share experiences. The author, who has been serving as an Associate Editor of the Brazilian journal Acta Cirurgica Brasileira over a long period of time, wishes to encourage physicians and researchers to submit their papers to medical journals. As we currently face the difficult battle against COVID-19 pandemic, physicians worldwide must team up and fight the virus for the safety of our future generations.

Abstract Technological advances such as optical instruments and surgical tools have enabled the considerable contributions of microsurgery to surgical therapies. Accordingly, surgical therapeutics has provided the latest information across a wide range of medical specialties, including immunology and pharmacology, despite specialization according to organs and organ systems. The International Society for Experimental Microsurgery, an academic organization, has utilized experimental microsurgery technology in the identification of curative concepts for diseases that remain difficult to treat. For this publication to mark the 32nd anniversary of the Brazilian Surgical Society, I introduced the following types of technology related to the further development of microsurgical technological innovations in the future: high-resolution three-dimensional (3D) video and touch-sensitive microsurgery robots.

ABSTRACT PURPOSE: Clinical microsurgery has been introduced in many fields, while experimental microsurgery has the cross-disciplinary features of the sciences and techniques for growth of medicine, pharmacology, veterinary, engineering etc. Training protocol, proposing a new name as Translational Microsurgery, was introduced. METHODS: Reconstructive skills of hepatic artery in pediatric living donor liver transplantation were summarized. Ex vivo training protocol using artificial blood vessel for surgeons was proposed. RESULTS: Clinical microsurgery requires anastomosis with delicate arteries and limited field of view. Our training protocol revealed that the relation between the score and speed was seen, while not all the surgeons with enough experience got high score. This training led to muster clinical skills and to apply excellent experimental works. CONCLUSIONS: Our microsurgical training protocol has been planned from the points of clinical setting. Training for vascular anastomosis led to rodent transplantation models. These models were used for immunology and immunosuppressant research. Microsurgical techniques led to master catheter technique and to inject various drugs or gene vectors.

We report two cases of diabetic patients with severe low back pain associated with retroperitoneal abscesses. In the first case, multiple retroperitoneal and spinal epidural abscesses were detected. Paraplegia due to the spinal epidural abscess was not relieved by drainage of the abscess and subsequent antibiotic therapy. In the second case, drainage of the retroperitoneal abscess and antibiotics were immediately started, resulting in successful recovery. Thus, we suggest that if a diabetic patient complains of low back pain, potential abscess formations should be considered and given appropriate treatment before administering epidural anesthetic injections for pain relief.