A Review on the 3D Printing of Functional Structures for Medical Phantoms and Regenerated Tissue and Organ Applications

Medical models, or ＂phantoms,＂ have been widely used for medical training and for doctor-patient interactions. They are increasingly used for surgical planning, medical computational models, algorithm verification and validation, and medical devices development. Such new applications demand high-fidelity, patient-specific, tissue-mimicking medical phantoms that can not only closely emulate the geometric structures of human organs, but also possess the properties and functions of the organ structure. With the rapid advancement of three-dimensional （3D） printing and 3D bioprinting technologies, many researchers have explored the use of these additive manufacturing techniques to fabricate functional medical phantoms for various applications. This paper reviews the applications of these 3D printing and 3D bioprinting technologies for the fabrication of functional medical phantoms and bio-structures. This review specifically discusses the state of the art along with new developments and trends in 3D printed functional medical phantoms （i.e., tissue-mimicking medical phantoms, radiologically relevant medical phantoms, and physiological medical phantoms） and 3D bio-printed structures （i.e., hybrid scaffolding materials, convertible scaffolds, and integrated sensors） for regenerated tissues and organs.

Liver transplantation using organs from deceased organ donors: a single organ transplant center experience

BACKGROUND： In 2011, a pilot program for deceased organ donation was initiated in China. We describe the first successful series of liver transplants in the pilot program.METHODS： From July 2011 to August 2012, our center performed 26 liver transplants from a pool of 29 deceased donors. All organ donation and allograft procurement were conducted according to the national protocol. The clinical data of donors and recipients were collected and summarized retrospectively.RESULTS： Among the 29 donors, 24 were China Category II donors（organ donation after cardiac death）, and five were China Category III donors（organ donation after brain death followed by cardiac death）. The recipients were mainly the patients with hepatocellular carcinoma. The one-year patient survival rate was 80.8% with a median follow-up of 422（2-696） days. Among the five mortalities during the follow-up,three died of tumor recurrence. In terms of post-transplant complications, 9 recipients（34.6%） experienced early allograft dysfunction, 1（3.8%） had non-anastomotic biliary stricture,and 1（3.8%） was complicated with hepatic arterial thrombosis.None of these complications resulted in patient death. Notably,primary non-function was not observed in any of the grafts.CONCLUSION： With careful donor selection, liver transplant from deceased donors can be performed safely and plays acritical role in overcoming the extreme organ shortage in China.

Depolarizing metrics in the biomedical field:Vision enhancement and classification of biological tissues

Polarimetry encompasses a collection of optical techniques broadly used in a variety of fields.Nowadays,such techniques have provided their suitability in the biomedical field through the study of the polarimetric response of biological samples(retardance,dichroism and depolarization)by measuring certain polarimetric observables.One of these features,depolarization,is mainly produced by scattering on samples,which is a predominant efiect in turbid media as biological tissues.In turn,retardance and dichroic efiects are produced by tissue anisotropies and can lead to depolarization too.Since depolarization is a predominant efiect in tissue samples,we focus on studying difierent depolarization metrics for biomedical applications.We report the suitability of a set of depolarizing observables,the indices of polarimetric purity(IPPs),for biological tissue inspection.We review some results where we demonstrate that IPPs lead to better performance than the depolarization index,which is a well-established and commonly used depolarization observable in the literature.We also provide how IPPs are able to significantly enhance contrast between difierent tissue structures and even to reveal structures hidden by using standard intensity images.Finally,we also explore the classificatory potential of IPPs and other depolarizing observables for the discrimination of difierent tissues obtained from ex vivo chicken samples(muscle,tendon,myotendinous junction and bone),reaching accurate models for tissue classification.

Tea polyphenol-gut microbiota interactions:hints on improving the metabolic syndrome in a multi-element and multi-target manner

The metabolic syndrome(MS)has become one of the main problems in public health.Tea polyphenols(TPs),the main bioactive components of tea,has been claimed to have the potential to regulate metabolism and effectively prevent or mitigate the MS.However,many studies into the effects of TPs on MS have provided conflicting findings and the underlying mechanism has been elusive.The predominant TPs in unfermentedand and fermented tea are catechins and oxidized polyphenols(theaflavins and thearubigins),both of which have low bioavailability and reach the colon where most gut microbes inhabit.Gut microbiota has been demonstrated to be tightly associated with host metabolism.The interactions between TPs and gut microbiota will lead to the alterations of gut microbiota composition and the production of metabolites including short chain fatty acids,bile acids,amino acids and TPs derived metabolites,accordingly exerting their biological effects both locally and systemically.This review highlighted the contribution of metabolites and specific gut bacteria in the process of TPs intervention on the MS and further discuss how TPs impact the MS via gut microbiota from the viewpoint of gut organ/tissue axis.

Rabies virus transmission via solid organs or tissue allotransplantation

Background:Rabies,for which the mortality rate is almost 100%,is a zoonotic viral disease that can be transmitted via solid organs or tissue allotransplantation.Dozens of deaths from rabies via solid organs or tissues allotransplantation(ROTA)have been documented during the last decades.In 2015 and 2016,two cases of rabies virus transmission via solid organs or tissue allotransplantation were reported in China,which further underscore the risk and importance of this special type of rabies for organ transplant recipients.Main text:From 1978 to 2017,at least 13 cases of ROTA,causing dozens of deaths,have been reported worldwide,whether in the high-risk or low-risk countries of rabies.The reported incubation period of ROTA ranges from 11 days to more than 17 months,while the historical incubation period of rabies is generally considered to range from~1 week to several years.The pathogenesis of ROTA is not clear,but the use of post-exposure prophylaxis(PEP)can play a protective role in the transplant recipients.We also summarize reports about ROTA in China,combined with the actual situation regarding work on rabies surveillance and elimination,and suggest countermeasures for the prevention and control of ROTA in the future.Conclusions:Understanding the significance of ROTA,screening the suspected organs,assessing the risk and protecting the related population will be effective way to prevent and control further occurrence of ROTA.

Medicinal Synthetic Aluminum-Magnesium Silicate {Al4(SiO4)3 + 3Mg2SiO4 → 2Al2Mg3(SiO4)3} —A Highly Active Anti-Retroviral Medicine

Medicinal synthetic Aluminum-magnesium silicate (MSAMS), which has inhibited Human immune deficiency virus (HIV), in vitro, was used for trial-treatment of HIV/AIDS patients. Their plasma were tested for viral loads (VL): before and repeatedly during the treatment. The regimen was: MSAMS (50 mg/kg), MSAMS-stabilized Ampicillin trihydrate (7.5 mg/kg) and immunace extra protection?. After 4 weeks, it was reduced to 50 mg/kg (MSAMS) and the immune stimulant. When VL decreased bellow 50/ml, the treatment continued, 4 weeks before stopping. Mean-VL of four patients increased (P = 0.006) from 498.50 ± 33.37 to 1,072.50 ± 184.55, after 3.75±2.06 weeks and decreased (P = 0.040) to 407.33 ± 297.27 (18.29%) when the treatment-duration increased to 6.67 ± 2.31 weeks. Prolonging the duration to 12.00 ± 2.83 weeks led to 98.68% decrease of mean-VL of four other patients, from 24,250.00 ± 15,939.34 to 321.00 ± 229.38(P = 0.045). Two HIV positive persons treated for 4 weeks after their VL reduced bellow 50/ml have remained healthy, 10 and 16 months respectively, without routine antiretroviral medication.

Rapid donor liver procurement with only aortic perfusion

AIM: To describe a rapid technique for procurement of donor liver with aortic perfusion only (APO). METHODS: Only the aorta is cannulated and perfused with chilled preservation solution. RESULTS: The quality of donor liver can ensure the grafted liver functions. CONCLUSION: The method of APO can simplify the operative procedure, compared with the dual cannulation. It also can minimize the danger of injuring vascular structures and involve less dissection.

Protective Effects of Radix Astragali Injection on Multiple Organs of Rats with Obstructive Jaundice

Objective： To investigate the protective effects and mechanisms of Radix Astragali Injection on multiple organs of rats with obstructive jaundice（OJ）. Methods： A total of 180 rats were randomly divided into the sham-operated, model control and treated groups（60 in each group）. On 7, 14, 21 and 28 days after operation, the serum contents of alanine aminotransferase（ALT）, aspartate aminotransferase（AST）, r-glutamyl transpeptidase（r-GT）, total bilirubin（TBil）, direct bilirubin（DBil）, blood urine nitrogen（BUN）, and creatinine（CREA） were determined. And the pathological changes of livers, kidneys and lungs, and protein expressions of toll-like receptor-4（TLR-4） of livers, intercellular adhesion molecule-1（ICAM-1） of lungs, Bax and nuclear factor-kappa B（NF-κB）, as well as apoptotic indexes of multiple organs were observed, respectively. Results： The pathological severity scores of multiple organs（including livers on 7, 14, 21 and 28 days, kidneys on 14 and 28 days, and lungs on 14 days）, serum contents of ALT（14 and 21 days）, AST（14 days）, TBil（7, 14, 21 and 28 days）, DBil（14 and 21 days）, BUN（28 days）, protein expressions of TLR-4（in livers, 28 days）, Bax（in livers and kidneys, 21 days）, and apoptotic indexes in livers（7 and 21 days） in the treated group were significantly lower than those in the model control group（P〈0.05 or P〈0.01）. Conclusion： Radix Astragali Injection exerts protective effects on multiple organs of OJ rats by improving the pathological changes of lung, liver and kidney, decreasing the serum index of hepatic and renal function as well as inhibiting the protein expression of TLR-4 and Bax in the livers and Bax in the kidneys.