A Novel Method of Cryopreservation of Rat and Human Hepatocytes by Using Encapsulation Technique and Possible Use for Cell Transplantation

2005 ◽  
Vol 14 (9) ◽  
pp. 609-620 ◽  
Author(s):  
Takeshi Aoki ◽  
Tomotake Koizumi ◽  
Yasuna Kobayashi ◽  
Daisuke Yasuda ◽  
Yoshihiko Izumida ◽  
...  
Keyword(s):  
Cell Transplantation ◽  
Clinical Application ◽  
Rat Hepatocytes ◽  
Hepatic Function ◽  
Human Hepatocytes ◽  
Hepatocyte Transplantation ◽  
Urea Synthesis ◽  
Novel Approach ◽  
Novel Method ◽  
Near Future

Encapsulated hepatocyte transplantation is a promising approach to cell transplantation without immunosuppression as an alternative to whole organ liver transplantation. However, the shortage of donor cells for hepatocyte transplantation has not been resolved, and at this critical point, it seems necessary to establish a method of hepatocyte cryopreservation to allow clinical application of hepatocyte transplantation and the development of a bioartificial liver system in the near future. In this study we demonstrated that cryopreserved microencapsulated rat and human hepatocytes can retain their hepatic function and that cryopreserved microencapsulated human hepatocytes transplanted into rat spleen remain viable without immunosuppression. Rat and human hepatocytes were isolated by a collagenase digestion method, and they were microencapsulated with poly-L-lysine. The microencapsulated rat hepatocytes were transferred to culture medium (DMEM containing 10% FBS and 10% DMSO) and immediately frozen in liquid nitrogen. A warm water bath (37°C) was used to thaw the microencapsulated hepatocytes. Hepatic function, drug metabolism, and cell morphology were assessed after 90 days of cryopreservation. After 1 week of cryopreservation, microencapsulated hepatocytes were cultured for up to 2 weeks to assess their hepatic function and morphology. The morphology of human hepatocytes was assessed after 30 days of cryopreservation. Cryopreserved human hepatocytes were transplanted into rat spleen to assess their morphology. Cryopreserved microencapsulated hepatocytes retained their viability and were strongly positive for expression of albumin, OAT2, CYP3A2, and CYP3A9. Two weeks after cultivation, the cryopreserved microencapsulated rat hepatocytes had retained their hepatic function (urea synthesis). Cryopreserved microencapsulated human hepatocytes also mainly survived and retained their hepatic function for at least 30 days after cryopreservation. Moreover, entrapped cryopreserved human hepatocytes also survived and expressed albumin in rat spleen after transplantation. We demonstrated a novel method of long-term cryopreservation of rat and human hepatocytes by using an encapsulation technique, with retention of biological activity and excellent survival of the cryopreserved microencapsulated human hepatocytes transplanted into rat spleen. We believe that this novel approach to hepatocytes cryopreservation provides a new direction in encapsulated cell therapy with the goal of clinical application in the near future.

Mesothelial Cells from Tunica Vaginalis, a Practical Source for Mesothelial Transplantation

2007 ◽  
Vol 30 (6) ◽  
pp. 495-500 ◽  
Author(s):  
T. Asano ◽  
R. Takazawa ◽  
M. Yamato ◽  
K. Kihara ◽  
T. Okano
Keyword(s):  
Cell Transplantation ◽  
Fetal Development ◽  
Mesothelial Cell ◽  
Mesothelial Cells ◽  
Clinical Use ◽  
Tunica Vaginalis ◽  
Physiological Conditions ◽  
Reliable Source ◽  
Novel Method ◽  
Near Future

Transplantation of mesothelial cells is used to repair peritoneum that is damaged by surgery, peritonitis, and peritoneal dialysis. The largest obstacle for clinical application of mesothelial cell transplantation is the lack of a reliable source of mesothelial cells. So far, they are isolated from omentum, mesentery, parietal wall and ascites. Procedures used to obtain mesothelial cells from the omentum or mesentery are invasive, however, especially in pre-operative situations. Sufficient amounts of ascites for aspiration can not be obtained under physiological conditions. We have developed a novel method of isolating mesothelial cells from the tunica vaginalis. The tunica vaginalis originates from the peritoneum and descends into the scrotum along with the testis during fetal development. This region provides a source of mesothelial cells that is convenient to approach and free from abdominal complications. Transplantation of autologous mesothelial cells that were isolated from tunica vaginalis was effective in preventing post-operative adhesions. In this review, we summarize mesothelial cell transplantation trials and describe the method of isolating mesothelial cells form the tunica vaginalis. Mesothelial cell transplantation might be widely accepted for clinical use in the near future.

scholarly journals Characterization of the human liver vasopressin receptor. Profound differences between human and rat vasopressin-receptor-mediated responses suggest only a minor role for vasopressin in regulating human hepatic function

1991 ◽  
Vol 276 (1) ◽  
pp. 189-195 ◽  
Author(s):  
J Howl ◽  
T Ismail ◽  
A J Strain ◽  
C J Kirk ◽  
D Anderson ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Glycogen Phosphorylase ◽  
Rat Hepatocytes ◽  
Hepatic Function ◽  
Human Hepatocytes ◽  
Minor Role ◽  
Receptor Subtype ◽  
Vasopressin Receptor ◽  
Vasopressin Receptors ◽  
A Minor

The [Arg8]vasopressin (AVP) receptor expressed by human hepatocytes was characterized, and compared with the rat hepatic V1a vasopressin receptor subtype. In addition to determining the pharmacological profile of the human receptor, the cellular responses to AVP were measured in human and rat hepatocytes by assaying glycogen phosphorylase alpha activity and DNA synthesis. Marked differences were observed between human and rat hepatocytes regarding vasopressin receptors and the intracellular consequences of stimulation by AVP. Data presented in this paper demonstrate the following, (i) Vasopressin V1a receptors are present in low abundance on human hepatocytes. (ii) Species differences exist between human and rat V1a receptors with respect to the affinity of some selective antagonists. (iii) AVP-stimulated glycogen phosphorylase a activation in human hepatocytes was approx. 5% of that observed in rat cells. (iv) In contrast with rat hepatocytes, DNA synthesis in human cells in culture was not stimulated by AVP. It is concluded that vasopressin plays only a minor role in the regulation of human hepatic function. Furthermore, conclusions drawn from observations made with AVP and its analogues on rat hepatic function cannot be directly extrapolated to the human situation.

Comparison of Pig, Human and Rat Hepatocytes as a Source of Liver Specific Metabolic Functions in Culture Systems - Implications for Use in Bioartificial Liver Devices

2001 ◽  
Vol 24 (6) ◽  
pp. 392-396 ◽  
Author(s):  
M.T. Vilei ◽  
A. Granato ◽  
C. Ferraresso ◽  
D. Neri ◽  
P. Carraro ◽  
...  
Keyword(s):  
Rat Hepatocytes ◽  
Bioartificial Liver ◽  
Human Hepatocytes ◽  
Urea Synthesis ◽  
Animal Cells ◽  
Liver Support ◽  
Metabolic Functions ◽  
Bioartificial Liver Support ◽  
Metabolic Activities ◽  
Liver Support Devices

The limited availability of human hepatocytes results in the use of animal cells in most bioartificial liver support devices. In the present work, clinically relevant liver specific metabolic activities were compared in rat, pig and human hepatocytes cultured on liver-derived biomatrix to optimize the expression of differentiated functions. Pig hepatocytes showed higher rates of diazepam metabolism (2.549±0.821 μg/h/million cells vs. 0.474±0.079 μg/h/million cells rats, p<0.005, and vs. 0.704±0.171 μg/h/million cells in man, p<0.005) and of bilirubin conjugation (21.60116±8.433237 μmoles/l/24 h vs. 6.786809±2.983758 in man, p<0.001 and vs. 9.956538±1.781016 μmoles/l/24 h in rats, p<0.005). Urea synthesis was similar in pig and in human hepatocytes (150±46.3 vs. 144.8±21.46 nmoles/h/million cells) and it was lower in rats (84.38±35.2; p<0.001 vs. man, p<0.02 vs. pig). High liver specific metabolic activities in cultured pig hepatocytes further support their use as a substitue for human cells in bioartificial liver devices

Hepatocyte Labeling with 99mTc-GSA: A Potential Non-Invasive Technique for Tracking Cell Transplantation

2012 ◽  
Vol 35 (6) ◽  
pp. 450-457 ◽  
Author(s):  
Manil Chouhan ◽  
Juliana Puppi ◽  
Estela Solanas ◽  
Ragai R. Mitry ◽  
Anil Dhawan ◽  
...  
Keyword(s):  
Rat Hepatocytes ◽  
Fold Increase ◽  
Cell Types ◽  
Human Hepatocytes ◽  
Hepatocyte Transplantation ◽  
Invasive Technique ◽  
Promising Alternative ◽  
And Function

Background: Hepatocyte transplantation is a promising alternative to orthotopic liver transplantation, however, the fate of transplanted hepatocytes is not well defined. 99mTc-galactosyl-serum albumin (99mTc-GSA) is a clinical scintigraphic agent which is specifically taken up by the hepatocyte asialoglycoprotein receptor (ASGPR). Aims: To investigate labeling of fresh and cryopreserved human hepatocytes and fresh rat hepatocytes in vitro using 99mTc-GSA Methods: Human and rat hepatocytes were isolated from liver tissue by collagenase perfusion. The ASGPR were characterized using immunohistochemistry and RT-PCR. Hepatocytes were incubated with 99mTc-GSA in suspension at 4°C and 37°C. Cell viability and function was determined using cell mitochondrial dehydrogenase (MTS) and sulphorhodamine B (SRB) assays. Results: Fresh and cryopreserved human hepatocytes expressed the ASGPR. Incubation of hepatocytes in suspension with 99mTc-GSA reduced the viability of hepatocytes, but this was similar to unlabeled control cells. Greater loss of viability was seen on incubation at 37°C compared to 4°C, but there was a significantly greater uptake of 99mTc-GSA at the physiological temperature (6.6 ± SE 0.6-fold increase, p<0.05) consistent with ASGPR-mediated endocytosis. MTS and SRB assays were not significantly affected by labeling with 99mTc-GSA in all three cell types. A mean of 18.5% of the radioactivity was released over 120 min when 99mTc-GSA - labeled hepatocytes were shaken in vitro at 37°C. Conclusions: Human and rat hepatocytes can be labeled with 99mTc-GSA, which may have potential application for in vivo imaging after hepatocyte transplantation.

Organic Reactivity Control by Means of Neighboring Groups and Organometallics. A Personal Account

1994 ◽  
Vol 59 (1) ◽  
pp. 1-74 ◽  
Author(s):  
Pavel Kočovský
Keyword(s):  
Transition Metals ◽  
Cyclopropane Ring ◽  
Allylic Substitutions ◽  
Recent Developments ◽  
Cardioactive Drug ◽  
Novel Method ◽  
Metal Catalyzed ◽  
Electrophilic Additions ◽  
Near Future ◽  
First Time

This review summarizes the main topics of our research and covers the period of the last 15 years. The prime interest is focused on various ways of controlling the regio- and stereoselectivity of selected organic reactions, in particular electrophilic additions, cleavage of cyclopropane rings, and allylic substitutions by means of neighboring groups and/or transition and non-transition metals. In the first part, the factors governing the course of electrophilic additions are assessed, culminating in the formulation of selection rules for the reactivity of cyclohexene systems, and in a concise synthesis of the natural cardioactive drug, strophanthidin. These studies also contribute to a better understanding of the mechanisms of electrophilic additions. The second part describes recent developments in the stereo- and regiocontrolled cleavage of cyclopropane rings by non-transition metals (Tl and Hg), and the reactivity and transmetalation (with Pd) of the primary products. This methodology has resulted in novel routes to unique polycyclic structures, and will have synthetic applications in the near future. Evidence for the stereospecific "corner" cleavage of the cyclopropane ring has been provided for the first time for Tl and later for Hg. The third part deals with transition metal-catalyzed allylic substitution. Evidence for a new "syn" mechanism for the formation of the intermediate (π-allyl)palladium complex has been provided, which runs counter to the generally accepted "anti" mechanism. A novel method for a Pd-catalyzed allylic oxidation has been developed and employed in the synthesis of natural sesquiterpenes. The increasing importance of transition and non-transition metals for synthetic organic chemistry is demonstrated by their unique reactivity in a number of the papers included in this review.

scholarly journals A novel approach to the computation of one-loop three- and four-point functions: I. The real mass case

2019 ◽  
Vol 2019 (11) ◽  
Author(s):  
J Ph Guillet ◽  
E Pilon ◽  
Y Shimizu ◽  
M S Zidi
Keyword(s):  
Building Blocks ◽  
The Real ◽  
Alternative Method ◽  
Novel Approach ◽  
Reduction Methods ◽  
Real Mass ◽  
Novel Method ◽  
Algebraic Reduction ◽  
The One ◽  
Mass Case

Abstract This article is the first of a series of three presenting an alternative method of computing the one-loop scalar integrals. This novel method enjoys a couple of interesting features as compared with the method closely following ’t Hooft and Veltman adopted previously. It directly proceeds in terms of the quantities driving algebraic reduction methods. It applies to the three-point functions and, in a similar way, to the four-point functions. It also extends to complex masses without much complication. Lastly, it extends to kinematics more general than that of the physical, e.g., collider processes relevant at one loop. This last feature may be useful when considering the application of this method beyond one loop using generalized one-loop integrals as building blocks.

scholarly journals Total Body Irradiation for Hematopoietic Stem Cell Transplantation: What Can We Agree on?

2021 ◽  
Vol 28 (1) ◽  
pp. 903-917
Author(s):  
Mitchell Sabloff ◽  
Steven Tisseverasinghe ◽  
Mustafa Ege Babadagli ◽  
Rajiv Samant
Keyword(s):  
Cell Transplantation ◽  
Total Body Irradiation ◽  
Hematopoietic Cell Transplantation ◽  
Conditioning Regimen ◽  
Late Toxicity ◽  
Hepatic Function ◽  
Vascular Supply ◽  
Entire Body ◽  
Hematopoietic Stem ◽  
Total Body

Total body irradiation (TBI), used as part of the conditioning regimen prior to allogeneic and autologous hematopoietic cell transplantation, is the delivery of a relatively homogeneous dose of radiation to the entire body. TBI has a dual role, being cytotoxic and immunosuppressive. This allows it to eliminate disease and create “space” in the marrow while also impairing the immune system from rejecting the foreign donor cells being transplanted. Advantages that TBI may have over chemotherapy alone are that it may achieve greater tumour cytotoxicity and better tissue penetration than chemotherapy as its delivery is independent of vascular supply and physiologic barriers such as renal and hepatic function. Therefore, the so-called “sanctuary” sites such as the central nervous system (CNS), testes, and orbits or other sites with limited blood supply are not off-limits to radiation. Nevertheless, TBI is hampered by challenging logistics of administration, coordination between hematology and radiation oncology departments, increased rates of acute treatment-related morbidity and mortality along with late toxicity to other tissues. Newer technologies and a better understanding of the biology and physics of TBI has allowed the field to develop novel delivery systems which may help to deliver radiation more safely while maintaining its efficacy. However, continued research and collaboration are needed to determine the best approaches for the use of TBI in the future.

HEPATOCYTE TRANSPLANTATION THROUGH THE HEPATIC VEIN: A NEW ROUTE OF CELL TRANSPLANTATION TO THE LIVER

2010 ◽  
Vol 90 ◽  
pp. 1042
Author(s):  
Y. Goto ◽  
K. Ohashi ◽  
R. Utoh ◽  
M. Yamamoto ◽  
T. Okano
Keyword(s):  
Cell Transplantation ◽  
Hepatic Vein ◽  
Hepatocyte Transplantation

scholarly journals Comparative metabolism of the antiviral dimer 3'-azido-3'-deoxythymidine-P-2',3'-dideoxyinosine and the monomers zidovudine and didanosine by rat, monkey, and human hepatocytes.

1997 ◽  
Vol 41 (11) ◽  
pp. 2502-2510 ◽  
Author(s):  
X R Pan-Zhou ◽  
E Cretton-Scott ◽  
X J Zhou ◽  
M Y Xie ◽  
R Rahmani ◽  
...  
Keyword(s):  
High Performance ◽  
Rat Hepatocytes ◽  
Human Hepatocytes ◽  
Metabolic Fate ◽  
Extracellular Medium ◽  
Isolated Rat Hepatocytes ◽  
Cell Extracts ◽  
Comparative Metabolism ◽  
Isolated Rat

AZT-P-ddI is an antiviral heterodimer composed of one molecule of 3'-azido-3'-deoxythymidine (AZT) and one molecule of 2',3'-dideoxyinosine (ddI) linked through their 5' positions by a phosphate bond. The metabolic fate of the dimer was studied with isolated rat, monkey, and human hepatocytes and was compared with that of its component monomers AZT and ddI. Upon incubation of double-labeled [14C]AZT-P-[3H]ddI in freshly isolated rat hepatocytes in suspension at a final concentration of 10 microM, the dimer was taken up intact by cells and then rapidly cleaved to AZT, AZT monophosphate, ddI, and ddI monophosphate. AZT and ddI so formed were then subject to their respective catabolisms. High-performance liquid chromatography analyses of the extracellular medium and cell extracts revealed the presence of unchanged dimer, AZT, 3'-azido-3'-deoxy-5'-beta-D-glucopyranosylthymidine (GAZT), 3'-amino-3'-deoxythymidine (AMT), ddI, and a previously unrecognized derivative of the dideoxyribose moiety of ddI, designated ddI-M. Trace extracellular but substantial intracellular levels of the glucuronide derivative of AMT (3'-amino-3'-deoxy-5'-beta-D-glucopyranosylthymidine [GAMT]) were also detected. Moreover, the extent of the formation of AMT, GAZT, and ddI-M from the dimer was markedly lower than that with AZT and ddI alone by the hepatocytes. With hepatocytes in primary culture obtained from rat, monkey, and human, large interspecies variations in the metabolism of AZT-P-ddI were observed. While GAZT and ddI-M, metabolites of AZT and ddI, respectively, as well as AZT 5'-monophosphate (MP) and ddI-MP were detected in the extracellular media of all species, AMT and GAMT were produced only by rat and monkey hepatocytes. No such metabolites were formed by human hepatocytes. The metabolic fate of the dimer by human hepatocytes was consistent with in vivo data recently obtained from human immunodeficiency virus-infected patients.

GPR-based novel approach for non-linear aerodynamic modelling from flight data

2018 ◽  
Vol 123 (1259) ◽  
pp. 79-92
Author(s):  
A. Kumar ◽  
A. K. Ghosh
Keyword(s):  
Aerodynamic Force ◽  
Equations Of Motion ◽  
Gaussian Process Regression ◽  
Likelihood Estimation ◽  
Flight Data ◽  
Novel Approach ◽  
Non Linear ◽  
Research Aircraft ◽  
Novel Method ◽  
Aerodynamic Modelling

ABSTRACTIn this paper, a Gaussian process regression (GPR)-based novel method is proposed for non-linear aerodynamic modelling of the aircraft using flight data. This data-driven regression approach uses the kernel-based probabilistic model to predict the non-linearity. The efficacy of this method is examined and validated by estimating force and moment coefficients using research aircraft flight data. Estimated coefficients of aerodynamic force and moment using GPR method are compared with the estimated coefficients using maximum-likelihood estimation (MLE) method. Estimated coefficients from the GPR method are statistically analysed and found to be at par with estimated coefficients from MLE, which is popularly used as a conventional method. GPR approach does not require to solve the complex equations of motion. GPR further can be directed for the generalised applications in the area of aeroelasticity, load estimation, and optimisation.

Sign in / Sign up

Export Citation Format

Share Document