Pseudotyping of Porcine Endogenous Retrovirus by Xenotropic Murine Leukemia Virus in a Pig Islet Xenotransplantation Model

The potential of porcine endogenous retrovirus (PERV) as a human pathogen, particularly as a public health risk, is a major concern for xenotransplantation. In vitro PERV transmission to human cells is well established. Evidence from human/pig hematopoietic chimeras in immunodeficient mice suggests PERV transmission from pig to human cells in vivo . However, recently Yang et al. demonstrated in such a model that PERV-C, a nonhuman-tropic class, could be transmitted via pseudotyping by xenotropic murine leukemia virus (X-MLV). We developed a mouse pig islet xenotransplant model, where pig and human cells are located in physically separate compartments, to directly assess PERV transmission from a functional pig xenograft. X-MLV efficiently pseudotypes all three classes of PERV, including PERV-A and -B that are known to productively infect human cell lines and PERV-C that is normally not infectious for human cells. Pseudotyping also extends PERV's natural tropism to nonpermissive, nonhuman primate cells. X-MLV is activated locally by the surgical procedure involved in the tissue transplants. Thus, the presence and activation of endogenous X-MLV in immunodeficient mice limits the clinical significance of previous reports of in vivo PERV transmission from pig tissues to human cells.     

Evidence of Absence of Porcine Endogenous Retrovirus (PERV) Infection in Patients Treated with a Bioartificial Liver Support System

Porcine endogenous retrovirus (PERV) genomes are present in all pig cells. In this retrospective study, we assessed PERV infectivity in 28 patients treated with an extracorporeal bioartificial liver (HepatAssist system) that includes a membrane device containing porcine hepatocytes. All patients tested negative for PERV using polymerase chain reaction analysis of peripheral blood mononuclear cells (PBMC) collected up to 5 years after treatment. In vitro results showed that the membrane decreased the risk of PERV transmission by a factor of 105, and porcine hepatocytes did not produce infectious PERV in co-cultures with human cell line 293. Our results do not support the presence of PERV infection in patients treated with this porcine hepatocyte-based bioartificial liver.     

Porcine Endogenous Retroviral Nucleic Acid in Peripheral Tissues Is Associated with Migration of Porcine Cells Post Islet Transplant

Porcine islets represent an alternative source of insulin-producing tissue, however, porcine endogenous retrovirus (PERV) remains a concern. In this study, SCID mice were transplanted with nonencapsulated (non-EC), microencapsulated (EC) or macroencapsulated (in a TheraCyte trade mark device) neonatal porcine islets (NPIs), and peripheral tissues were screened for presence of viral DNA and mRNA. To understand the role of an intact immune system in PERV incidence, mice with established NPI grafts were reconstituted with splenocytes. Peripheral tissues were screened for PERV and porcine DNA using PCR. Tissues with positive DNA were analyzed for PERV mRNA using RT-PCR. No significant difference was observed between non-EC and EC transplants regarding presence of PERV or porcine-specific DNA or mRNA. In reconstituted animals, little PERV or porcine DNA, and no PERV mRNA was detected. No PERV or porcine-specific DNA was observed in animals implanted with a TheraCyte trade mark device. In conclusion, an intact immune system significantly lowered the presence of PERV. Microencapsulation of islets did not alter PERV presence, however, macroencapsulation in the TheraCyte device did. Lower PERV incidence coincided with lower porcine DNA in peripheral tissues, linking the presence of PERV to migration of porcine cells.     

Islet Survival and Function Following Intramuscular Autotransplantation in the Minipig

The liver may not be an optimal site for islet transplantation due to obstacles by an instant blood‐mediated inflammatory response (IBMIR), and low revascularization of transplanted islets. Therefore, intramuscular islet transplantation (IMIT) offers an attractive alternative, based on its simplicity, enabling easier access for noninvasive graft imaging and cell explantation. In this study, we explored the outcome of autologous IMIT in the minipig (n = 30). Using the intramuscular injection technique, we demonstrated by direct histological evidence the rapid revascularization of islets autotransplanted into the gracilius muscle. Islet survival assessment was performed using immunohistochemistry staining for insulin and glucagon up to a period of 6 months. Furthermore, we showed the crucial role of minimizing mechanical trauma to the myofibers and limiting exocrine contamination. Intramuscular islet graft function after transplantation was confirmed by documenting the acute insulin response to intravenous glucose in 5/11 pancreatectomized animals. Graft function after IMIT remained however significantly lower than the function measured in 12 out of 18 minipigs who received a similar islet volume in the liver through intraportal infusion. Collectively, these results demonstrated in a clinically relevant preclinical model, suggest IMIT as a promising alternative to intraportal infusion for the transplantation of β cells in certain medical situations.     

Measurement of Morphologic Changes Induced by Trauma with the Use of Coherence Tomography in Porcine Vocal Cords

BACKGROUND AND OBJECTIVE: To evaluate the ability of optical coherence tomography (OCT) (a noncontact, high-resolution imaging technique that generates detailed cross-sectional images of tissue structure) to image and document acute response to trauma in the larynx. MATERIALS AND METHODS: Porcine larynges were dissected to expose the vocal cords. Vocal cords were imaged with 1310 nanometer (nm) light source with a bandwidth of 75 nm at 1 frame/second (s). Vocal cord injuries were simulated by applying topical phenolic acid, injecting titanium dioxide into the submucosa, and carbon dioxide laser irradiation. RESULTS: The epithelium, basement membrane, and lamina propria were clearly delineated, and the effect of each intervention could be monitored as lesions progressed. The OCT image corresponded closely with histology. CONCLUSION: OCT is a powerful imaging tool with the potential for use in real time and has potential for multiple clinical applications in the larynx.     

Improved Reflux Monitoring in the Acute Gastroesophageal Reflux Porcine Model Using Esophageal Multichannel Intraluminal Impedance Measurement

Background  Acute animal models are needed to obtain further insights into the mechanism of gastroesophageal reflux disease. Existing acute models use imprecise methods to detect reflux. The aim of the present study was to evaluate the potential of esophageal multichannel intraluminal impedance measurement (MII) to improve the quality of results of acute reflux porcine models. Materials and Methods  MII was used in ten pigs to monitor gastroesophageal reflux. Measurements were obtained (A) before and (B) after mobilization of the esophagus and (C) after myotomy. The results were compared to those obtained when reflux was monitored by esophageal drainage of intragastrically infused blue solution (DBS). Results  The times to first appearance of reflux were 67% (A), 86% (B), and 57% (C) of those by DBS when detected by MII; p < 0.05. The respective values for intragastric pressures needed to provoke reflux were 46%, 76%, and 66%; p < 0.05. Although the lower esophageal sphincter pressure decreased by 69% after (B) the intragastric pressure needed to provoke reflux increased by 140%; p < 0.05. Conclusions  MII improves the detection of reflux in the acute reflux porcine model. The finding that after sole mobilization of the esophagus the intragastric pressure needed to provoke reflux was increased although the finding that the pressure of the lower esophageal sphincter was decreased needs further investigation.     

Topical Zinc Oxide Treatment Increases Endogenous Gene Expression of Insulin-Like Growth Factor-1 in Granulation Tissue from Porcine Wounds

Application of zinc oxide has been shown to accelerate the healing of both chronic and acute wounds, but the mechanisms are unknown. We quantified the gene expression (mRNA) for one important growth factor, insulin-like growth factor 1 (IGF-1) in 12 full-thickness wounds in each of three domestic pigs treated with or without topical zinc oxide. We used a RNAase protection/solution hybridisation technique to measure IGF-1 mRNA concentrations, which were 50% higher in the granulation tissue in wounds treated with zinc oxide compared with control wounds on days 3–4 (p < 0.05), but not thereafter (up to postoperative day 11). Topical zinc oxide increased the healing rate of wounds compared to the control group (p < 0.01). The cell composition of the granulation tissue was similar in the two groups. The increased gene expression of IGF-1 may be one mechanism by which topical zinc oxide enhances wound healing.     

A Drug Holiday Reduces the Frequency and Severity of Medication-Related Osteonecrosis of the Jaw in a Minipig Model

Treatment of medication-related osteonecrosis of the jaw (MRONJ) is challenging and no clear consensus has been achieved. This study investigated preventive measures recommended for tooth extractions under antiresorptive (AR) treatment and the role of discontinuation of AR therapy to avoid the onset of MRONJ in a minipig model. Thirty-six Göttingen minipigs were divided into four groups. Group 1 (negative control): tooth extractions but no zoledronate (ZOL). Group 2 (positive control): weekly ZOL infusions for 12 weeks followed by tooth extractions without wound management followed by 8 weeks of ZOL treatment. Group 3: weekly ZOL infusions for 12 weeks followed by tooth extractions; surgical wound management (resection of sharp bone edges, mucoperiosteal coverage); and continuation of ZOL infusions for 8 weeks plus antibiotic treatment. Group 4: 12 weeks of ZOL infusions followed by a drug holiday for 6 weeks. Tooth extractions with preventive wound management followed by antibiotic treatment for 8 weeks but no ZOL infusions. Jawbones were subjected to macroscopic, radiological (CT and micro-CT) and histopathological investigations. No clinical cases of MRONJ were observed in the negative group, in the positive control all animals developed MRONJ. Group 3 developed MRONJ in 83% of cases. With a drug holiday, 40% developed MRONJ in areas of tooth extraction. This is the first large animal model that reduces the occurrence of MRONJ following tooth extraction by the implementation of a drug holiday combined with antibiotic prophylaxis and smoothening of sharp bony edges. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research..     

Study of renal function matching between Banna Minipig Inbred line and human

Pigs have been thought to be ideal candidates for xenotransplant donors. However besides the immunological barrier, physiological and pharmacokinetic comparabilities of kidney function between donor animals and humans are important factors for successful xenotransplantation. As a unique large inbred animal, Banna Minipig Inbred (BMI) has been reported to be a potential large animal suitable for xenotransplantation. However, its physical and pharmacokinetic compatibilities with humans have not been documented. The purpose of this investigation was to measure renal routine function, glomerular filtration rate (GFR), renal blood flow (ERPF), and drug metabolism to evaluate comparability to humans. The results suggested that the renal function of BMI was similar to that of humans to eliminate nonprotein nitrogenous end products of metabolism. Pharmacokinetics of p-aminohippurate (PAH) and inulin--the most widely used methods to assess ERPF and GFR--showed that BMI showed lower values than humans for GFR, but similar function to humans in ERPF. The pharmacokinetics of cefazolin; a widely used model drug to study kidney drug metabolizing capacity, showed greater overall renal drug elimination of BMI than of humans. These results suggested that BMI did show comparable data to human renal function.     

国人胫骨内侧平台后倾角的测量及不同测量方法的比较

目的 :测量中国人膝关节胫骨内侧平台后倾角的大小 ,比较不同测量方法间的差异 ,为开发国人膝关节假体及手术安装假体提供参数。方法 :在 80例膝关节骨性关节炎、40例类风湿性关节炎和 6 0例半月板损伤患者共 36 0个膝关节侧位片上 ,测量胫骨内侧平台前后缘连线分别与胫骨中上段前侧骨皮质切线的垂线 (方法 1)、胫骨结节下胫骨中上段轴线的垂线 (方法 2 )以及胫骨后侧皮质切线的垂线 (方法 3)的交角 ,得到不同测量方法的后倾角值。结果 :方法 1为( 11.74± 3 .87)°( -1.5～ 2 2 .5°) ,方法 2为 ( 8.91± 3 .5 7)°( -2 .5～ 19.5°) ,方法 3为 ( 6 .2 1± 3 .5 1)°( -6～ 17°)。 3种测量方法之间差异有非常显著意义 ,并高度相关。不同病种和性别间差异无显著性 ,与年龄相关性较低。与国外报道的相同方法测得数据有显著性差异。结论 :中国人胫骨内侧平台后倾角较小 ,胫骨平台后倾角个体差异较大 ,术中截骨应根据个体情况来决定。     

国人正常髌骨厚度测量

目的：测量国人正常髌骨厚度，为改进及设计国人髌骨假体提供参考数据。方法：测量１０２０例国人正常膝关节Ｘ线侧位片髌骨厚度。结果：测得国人髌骨厚度为２１．８４±０．１６ｍｍ。结论：首次报道了国人髌骨厚度的资料，为国人髌骨假体的设计提供了Ｘ线依据，并为髌骨置换中采取适合国人解剖特点髌骨截骨原则提供数据参考     

国人正常膝关节三维几何形态测量及相关研究

目的:利用计算机辅助设计技术建立国人正常膝关节三维模型并行骨形态测量研究,得到国人膝关节相关指标正常参考值,探讨此方法对假体设计的指导意义.方法:对120例240个正常成人膝关节CT扫描输出的原始数据进行三维重建,测量相关参数.结果:股骨内、外侧髁宽度与胫骨内、外侧平台宽度相近;股骨髁宽相对于胫骨平台宽比值在1.01～1.08之间,相对于股骨髁前后径比值在1.12～1.23之间;股骨髁宽与胫骨平台宽呈正相关.股骨后髁内、外侧关节面呈半径相等的圆形结构,股骨髁上轴线在膝关节屈曲时可以近似为屈曲固定轴.结论:建立了国人正常膝关节相关参数指标正常参考值;计算机辅助设计技术为膝关节复杂表面几何大体形态学研究提供一种良好的手段.     

中国未婚青年女性乳头位置的测定及相关因素分析

目的探讨中国未婚青年女性乳房乳头美学标准的正常值,为乳房整形术提供参考和依据。方法测量564例健康未婚青年女性的身高、体重、胸围、乳头间距、乳头-乳房下皱襞间距和锁骨中点-乳头间距等项目,计算各测量值的均值和标准差,对与乳头位置定位有关的各项指标用SPSS11.0统计软件进行相关性分析。结果研究显示乳头位置定位指标锁骨中点-乳头间距、乳头-乳房下皱襞间距、乳头间距的均值和标准差分别为（19.349±1.959）cm、（6.491±1.134）cm、（18.540±1.610）cm。锁骨中点-乳头间距与身高、体重和胸围的关系密切,而乳头-乳房下皱襞间距及乳头间距与身高差异无统计学意义,但与体重和胸围密切相关。结论符合美学标准的未婚青年女性乳房乳头位置的测定,可为乳房整形和再造提供理论依据。     

Breast Volume Measurement in Young Chinese Women and Clinical Applications

The authors carried out research on breast volume and body surface anatomy of 125 women. As a result, an average breast volume for Chinese women was obtained (325.36 ± 12.66 ml), and a table with several linear equations for calculating breast volume was derived. The authors applied these results to their clinical work and succeeded in making mammaplasty more precise in 178 patients.     

Retrovirus type C in the mouse bladder carcinoma cell line MBT-2

PURPOSE: The presence of replicating type C retrovirus in MBT-2 mouse bladder carcinoma cells is reported. This MBT-2 tumor cell line is nowadays globally distributed. The cells have been and are still used to study various aspects of bladder cancer. While studying the phagocytic capacity of MBT-2 cells for BCG organisms by electron microscopic methods, the presence of this retrovirus was noticed. MATERIALS AND METHODS: MBT-2 cells that were cultured in vitro as well as cells from intravesically and intradermally grown MBT-2 tumors from syngeneic mice were investigated using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques. RESULTS: All samples including the earliest generation MBT-2 cells that could be traced from stocks of other research groups contained the C type retrovirus, suggesting a contamination in all available generations of the MBT-2 cell line. CONCLUSIONS: As this tumor cell line is widely used in immunologic studies of the response to bladder cancer, it is important to consider the possible presence of type C viruses and associated antigens, since they could contribute to or interfere with the responses being measured. Studies should be initiated to determine whether viral antigen expression is involved in the immune rejection of MBT-2 bladder cancer. As a consequence, clinical implementation of immunological treatment strategies should not be based on results obtained with the MBT-2 model alone, but preferably should be confirmed with other (bladder) carcinoma models.