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1.
Andrologia ; 52(1): e13352, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31746491

RESUMEN

Histone phosphorylation, an epigenetic post-translational modification, plays essential roles in male gamete chromatin compaction during spermatogenesis and sperm maturity. Previously, we studied the epigenetic marker of phosphorylated serine 1 of histone H2A and H4 (HS1ph) during spermatogenesis in mice and crabs, which was shown to be closely related to the sperm maturity. To further investigate the correlation between phosphorylated serine 1 of histone H4 (H4S1ph) and sperm maturation, a comparison study was conducted in this work between the healthy and the precocious crabs. It was discovered that the distribution of H4S1ph was similar for the two groups of crabs during spermatogenesis before maturity, but totally different in the sperm nuclei. H4S1ph vanished in the nuclei of healthy crab spermatozoa mostly, while retained in the precocious crabs just like what it was in elongated spermatid of both kinds of crabs. The results showed that a high level of H4S1ph conservation was closely associated with immaturity and might indicate inefficient fertility of male precocious crabs. Thus, H4S1ph was suggested to be an epigenetic marker of sperm maturity.


Asunto(s)
Epigénesis Genética/fisiología , Histonas/genética , Pubertad Precoz/genética , Maduración del Esperma/genética , Animales , Braquiuros , Núcleo Celular/genética , Núcleo Celular/metabolismo , Modelos Animales de Enfermedad , Fertilidad/genética , Histonas/metabolismo , Humanos , Masculino , Fosforilación , Serina/metabolismo , Espermatozoides/fisiología , Testículo/anatomía & histología , Testículo/fisiología
2.
Langmuir ; 35(23): 7560-7570, 2019 06 11.
Artículo en Inglés | MEDLINE | ID: mdl-30550289

RESUMEN

The lack of an effective rewarming technique restricted the successful cryopreservation of organ or large tissues by vitrification. The conversion of electromagnetic (EM) energy into heat provides a possible solution for the rewarming process for the cryopreservation. In this work, an EM resonance rewarming system was set up with dynamic feedback control and power feeding optimization. In addition, we take advantage of magnetic nanoparticles (MNPs) to absorb magnetic field energy to further enhance the energy conversion efficiency. We achieved a >200 °C min-1 rewarming rate for tens of milliliters of cryopreserved samples. Besides, we also investigated the effect of nanoparticle size and concentration based on thermal properties by analyzing the contribution of nanoparticles and the utilization of field energy. The closed system reduced the possible concomitant side effects when increasing the number of nanoparticles or increasing the EM source power. With the remarkably low dosage of nanoparticles (0.1 mg mL-1 Fe) compared to that for other MNP-based rewarming applications, this study opens the door to new approaches for exploring novel techniques for tissue and organ preservation.

3.
Cryobiology ; 72(1): 21-6, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26705894

RESUMEN

It was recently reported that nanoparticles could significantly modulate the thermal properties of solutions at subzero temperatures, and as a result, nanoparticles have been widely used in both cryopreservation and cryosurgery. In cryopreservation, the water permeability coefficient of cell membrane is an essential parameter for quantitative investigation of cell dehydration and intracellular ice formation. However, few studies were focused on the effects of nanoparticles on the permeability properties of cell membrane. In order to optimize the processes of cryopreservation with nanoparticles, we measured the permeability properties of Sf21 cells in the presence of iron oxide nanoparticles in this study. The responses of Sf21 cells with iron oxide nanoparticles were obtained by the microperfusion system at -2, 5, 15 and 25 °C, respectively. The osmotically inactive cell volume (Vb), the cell membrane hydraulic conductivity (Lp) and it's activation energy (ELp), and the reference value of Lp at the reference temperature (Lpg) with 0.02%, 0.1% and 0.5% (w/w) iron oxide nanoparticles were determined by 2-parameter (2-p) model at -2, 5, 15 and 25 °C. We analyzed the effects of iron oxide nanoparticles on the permeability properties of the Sf21 cells. The results indicated that iron oxide nanoparticles have a significant influence on membrane permeability properties (Lpg and ELp) of Sf21 cells. The introduction of iron oxide nanoparticles tends to increase the values of Vb and Lpg, while decrease the value of ELp. These findings may provide a new route to optimize the biomaterial cryopreservation.


Asunto(s)
Permeabilidad de la Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , Criopreservación/métodos , Compuestos Férricos/farmacología , Nanopartículas del Metal , Animales , Línea Celular , Tamaño de la Célula , Frío , Técnicas Analíticas Microfluídicas , Ósmosis , Células Sf9 , Spodoptera/citología , Agua/metabolismo
4.
Cryobiology ; 72(2): 93-9, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26976225

RESUMEN

Cryopreservation of specimens taken from the genital tract of women is important for studying mucosal immunity during HIV prevention trials. However, it is unclear whether the current, empirically developed cryopreservation procedures for peripheral blood cells are also ideal for genital specimens. The optimal cryopreservation protocol depends on the cryobiological features of the cells. Thus, we obtained tissue specimens from vaginal repair surgeries, isolated and flow cytometry-purified immune cells, and determined fundamental cryobiological characteristics of vaginal CD3(+) T cells and CD14(+) macrophages using a microfluidic device. The osmotically inactive volumes of the two cell types (Vb) were determined relative to the initial cell volume (V0) by exposing the cells to hypotonic and hypertonic saline solutions, evaluating the equilibrium volume, and applying the Boyle van't Hoff relationship. The cell membrane permeability to water (Lp) and to four different cryoprotective agent (CPA) solutions (Ps) at room temperature were also measured. Results indicated Vb values of 0.516 V0 and 0.457 V0 for mucosal T cells and macrophages, respectively. Lp values at room temperature were 0.196 and 0.295 µm/min/atm for T cells and macrophages, respectively. Both cell types had high Ps values for the three CPAs, dimethyl sulfoxide (DMSO), propylene glycol (PG) and ethylene glycol (EG) (minimum of 0.418 × 10(-3) cm/min), but transport of the fourth CPA, glycerol, occurred 50-150 times more slowly. Thus, DMSO, PG, and EG are better options than glycerol in avoiding severe cell volume excursion and osmotic injury during CPA addition and removal for cryopreservation of human vaginal immune cells.


Asunto(s)
Permeabilidad de la Membrana Celular/fisiología , Criopreservación/métodos , Crioprotectores/metabolismo , Macrófagos/inmunología , Presión Osmótica/fisiología , Linfocitos T/inmunología , Transporte Biológico , Tamaño de la Célula , Dimetilsulfóxido/metabolismo , Glicol de Etileno/metabolismo , Femenino , Glicerol/metabolismo , Humanos , Ósmosis/fisiología , Propilenglicol/metabolismo , Soluciones , Vagina/citología , Vagina/inmunología , Agua/metabolismo
5.
Cryobiology ; 68(2): 294-302, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24582893

RESUMEN

The objective of this study is to determine the cryobiological characteristics of human embryonic kidney (HEK293T) cells. The cell membrane hydraulic conductivity (L(pg)) and the activation energy of water transport (E(Lp)) were determined in the absence/presence of cryoprotectant agent (CPA), while the nucleation rate kinetic and thermodynamic parameters (Ωo(SCN) and κo(SCN)) were determined in the absence of CPA. Since dehydration and intracellular ice formation (IIF) are two factors that may cause damage to cells during the freezing process, systematical freezing experiments were carried out at different cooling rates (5, 10, 15, 20, 30, and 60°C/min) under the commercial available cryomicroscopy (FDCS 196, Linkham, Waterfield, UK) to further explore the cryoinjury mechanism for HEK293T cells. By simultaneously fitting the water transport equation to the experimentally measured volumetric shrinkage data at 5, 10, and 15°C/min, the "combined best fit" membrane permeability parameters for HEK293T cells in both phosphate buffer saline (PBS) and CPA media (0.75M Me2SO in PBS) are determined. They are L(pg)=2.85×10(-14)m/s/Pa (0.17µm/min/atm), E(Lp)=142.91kJ/mol (34.13kcal/mol) (R(2)=0.990), and L(pg)[cpa]=2.73±0.44×10(-14)m/s/Pa (0.16±0.03µm/min/atm), E(Lp)[cpa]=152.52±27.69kJ/mol (36.42±6.61kcal/mol) (R(2)=0.993), respectively. An optimal cooling rate B(opt) (the highest cooling rate without IIF) was determined to be 14.24°C/min in the absence of CPA. Additionally, the ice nucleation parameters (Ωo(SCN) and κo(SCN)) were averaged to be 1.31±0.11×10(8)m(-2)s(-1) and 7.67±2.55×10(9)K(5) for the cooling rates 20, 30, and 60°C/min.


Asunto(s)
Transporte Biológico/fisiología , Criopreservación/métodos , Congelación , Células HEK293/citología , Células HEK293/metabolismo , Hielo , Permeabilidad de la Membrana Celular , Crioprotectores/farmacología , Humanos
6.
Biopreserv Biobank ; 2023 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-37751240

RESUMEN

Cryopreservation is the most effective technology for the long-term preservation of biological materials, including cells, tissues, and even organs in the future. The process of cooling and rewarming is essential to the successful preservation of biological materials. One of the critical problems in the development of cryopreservation is the optimization of effective rewarming technologies. This article reviewed rewarming methods, including traditional boundary rewarming commonly used for small-volume biological materials and other advanced techniques that could be potentially feasible for organ preservation in the future. The review focused on various rewarming technique principles, typical applications, and their possible limitations for cryopreservation of biological materials. This article introduced nanowarming methods in the progressing optimization and the possible difficulties. The trends of novel rewarming methods were discussed, and suggestions were given for future development.

7.
J Clin Microbiol ; 50(11): 3575-80, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22933596

RESUMEN

Successful long-term preservation of Mycobacterium tuberculosis cells is important for sample transport, research, biobanking, and the development of new drugs, vaccines, biomarkers, and diagnostics. In this report, Mycobacterium bovis bacillus Calmette-Guérin and M. tuberculosis H37Ra were used as models of M. tuberculosis complex strains to study cryopreservation of M. tuberculosis complex cells in diverse sample matrices at different cooling rates. Cells were cryopreserved in diverse sample matrices, namely, phosphate-buffered saline (PBS), Middlebrook 7H9 medium with or without added glycerol, and human sputum. The efficacy of cryopreservation was quantified by microbiological culture and microscopy with BacLight LIVE/DEAD staining. In all sample matrices examined, the microbiological culture results showed that the cooling rate was the most critical factor influencing cell viability. Slow cooling (a few degrees Celsius per minute) resulted in much higher M. tuberculosis complex recovery rates than rapid cooling (direct immersion in liquid nitrogen) (P < 0.05). Among the three defined cryopreservation media (PBS, 7H9, and 7H9 plus glycerol), there was no significant differential effect on viability (P = 0.06 to 0.87). Preincubation of thawed M. tuberculosis complex cells in 7H9 broth for 20 h before culture on solid Middlebrook 7H10 plates did not help the recovery of the cells from cryoinjury (P = 0.14 to 0.71). The BacLight LIVE/DEAD staining kit, based on Syto 9 and propidium iodide (PI), was also applied to assess cell envelope integrity after cryopreservation. Using the kit, similar percentages of "live" cells with intact envelopes were observed for samples cryopreserved under different conditions, which was inconsistent with the microbiological culture results. This implies that suboptimal cryopreservation might not cause severe damage to the cell wall and/or membrane but instead cause intracellular injury, which leads to the loss of cell viability.


Asunto(s)
Criopreservación/métodos , Viabilidad Microbiana/efectos de la radiación , Mycobacterium bovis/fisiología , Mycobacterium bovis/efectos de la radiación , Mycobacterium tuberculosis/fisiología , Mycobacterium tuberculosis/efectos de la radiación , Recuento de Colonia Microbiana , Medios de Cultivo/química , Microscopía , Coloración y Etiquetado
8.
Biopreserv Biobank ; 20(4): 317-322, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35984939

RESUMEN

Rapid and uniform rewarming has been proved to be beneficial, and sometimes indispensable for the survival of cryopreserved biomaterials, inhibiting ice-recrystallization-devitrification and thermal stress-induced fracture (especially in large samples). To date, the convective water bath remains the gold standard rewarming method for small samples in the clinical settings, but it failed in the large samples (e.g., cryopreserved tissues and organs) due to damage caused by the slow and nonuniform heating. A single-mode electromagnetic resonance (SMER) system was developed to achieve ultrafast and uniform rewarming for large samples. In this study, we investigated the heating effects of the SMER system and compared the heating performance with water bath and air warming. A numerical model was established to further analyze the temperature change and distribution at different time points during the rewarming process. Overall, the SMER system achieved rapid heating at 331.63 ± 8.59°C min-1 while limiting the maximum thermal gradient to <9°C min-1, significantly better than the other two warming methods. The experimental results were highly consistent, indicating SMER is a promising rewarming technology for the successful cryopreservation of large biosamples.


Asunto(s)
Criopreservación , Recalentamiento , Criopreservación/métodos , Fenómenos Electromagnéticos , Agua
9.
Biosens Bioelectron ; 197: 113786, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-34801797

RESUMEN

Rapid and accurate clinical assessment of hemostasis is essential for managing patients who undergo invasive procedures, experience hemorrhages, or receive antithrombotic therapies. Hemostasis encompasses an ensemble of interactions between the cellular and non-cellular blood components, but current devices assess only partial aspects of this complex process. In this work, we describe the development of a new approach to simultaneously evaluate coagulation function, platelet count or function, and hematocrit using a carbon nanotube-paper composite (CPC) capacitance sensor. CPC capacitance response to blood clotting at 1.3 MHz provided three sensing parameters with distinctive sensitivities towards multiple clotting elements. Whole blood-based hemostasis assessments were conducted to demonstrate the potential utility of the developed sensor for various hemostatic conditions, including pathological conditions, such as hemophilia and thrombocytopenia. Results showed good agreements when compared to a conventional thromboelastography. Overall, the presented CPC capacitance sensor is a promising new biomedical device for convenient non-contact whole-blood based comprehensive hemostasis evaluation.


Asunto(s)
Técnicas Biosensibles , Trastornos de la Coagulación Sanguínea , Nanotubos de Carbono , Coagulación Sanguínea , Hemostasis , Humanos
10.
Biomed Microdevices ; 13(5): 923-8, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21710370

RESUMEN

Obtaining accurate thermal properties of biomaterials plays an important role in the field of cryobiology. Currently, thermal needle, which is constructed by enclosing a manually winded thin metal wire with an insulation coating in a metallic sheath, is the only available device that is capable of measuring thermal conductivity of biomaterials. Major drawbacks, such as macroscale sensor size, lack of versatile format to accommodate samples with various shapes and sizes, neglected effects of heat transfer inside the probe and thermal contact resistance between the sensing element and the probe body, difficult to mass produce, poor data repeatability and reliability and labor-intense sensor calibration, have significantly reduced their potential to be an essential measurement tool to provide key thermal property information of biological specimens. In this study, we describe the development of an approach to measure thermal conductivity of liquids and soft bio-tissues using a proof-of-concept MEMS based thermal probe. By employing a microfabricated closely-packed gold wire to function as the heater and the thermistor, the presented thermal sensor can be used to measure thermal conductivities of fluids and natural soft biomaterials (particularly, the sensor may be directly inserted into soft tissues in living animal/plant bodies or into tissues isolated from the animal/plant bodies), where other more standard approaches cannot be used. Thermal standard materials have been used to calibrate two randomly selected thermal probes at room temperature. Variation between the obtained system calibration constants is less than 10%. By incorporating the previously obtained system calibration constant, three randomly selected thermal probes have been successfully utilized to measure the thermal conductivities of various solutions and tissue samples under different temperatures. Overall, the measurements are in agreement with the recommended values (percentage error less than 5%). The microfabricated thermal conductivity sensor offers superior characteristics compared to those traditional macroscopic thermal sensors, such as, (a) reduced thermal mass and thermal resistivity, (b) improved thermal contact between sensor and sample, (c) easy to manufacture with mass production capability, (d) flexibility to reconfigure sensor geometries for measuring samples with various sizes and shapes, and (e) reduced calibration workload for all sensors microfabricated from the same batch. The MEMS based thermal conductivity sensor is a promising approach to overcome the inherent limitations of existing macroscopic devices and capable of delivering accurate thermal conductivity measurement of biomaterials with various shapes and sizes.


Asunto(s)
Materiales Biocompatibles/análisis , Microtecnología/instrumentación , Conductividad Térmica , Termómetros , Tejido Adiposo/química , Animales , Calibración , Dimetilsulfóxido/química , Diseño de Equipo , Glicol de Etileno/química , Malus/química , Músculos/química , Soluciones/análisis , Porcinos , Temperatura
11.
J Biomech Eng ; 133(2): 021007, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21280879

RESUMEN

In most cryopreservation applications, the final concentrations of cryoprotective agents (CPAs) must be reduced to biocompatible levels. However, traditional methods for removing CPAs usually have disadvantages of operation complexity, time consumption, and ease of contamination, especially for the applications involving large volumes of cell suspensions. A dilution-filtration system, which involves pure ultrafiltration for separation, was developed for continuous, automatic, and closed process of removing CPAs. To predict the optimal protocols under given experimental conditions, a theoretical model was established first. Cell-free experiments were then conducted to investigate the variation in CPA concentration during the process, and the experimental data were compared with the theoretical values for the validation of the model. Finally, ten units (212.9 ml/unit±9.5 ml/unit) of thawed human red blood cells (cryopreserved with 40% (w/v) glycerol) were deglycerolized using the theoretically optimal operation protocols to further validate the effectiveness and advantage of the system. In the cell-free experiments, glycerol was continuously removed and the concentration variations fitted the simulated results quite well. In the in-vitro experiments, glycerol concentration in RBC suspension was reduced to 5.57 g/l±2.81 g/l within an hour, and the cell count recovery rate was 91.19%±3.57%, (n=10), which proves that the system is not only safe for removing CPAs, but also particularly efficient for processing large-scale samples. However, the operation parameters must be carefully controlled and the optimal protocols should be specialized and various from case to case. The presented theoretical model provides an effective approach to find out the optimal operation protocols under given experimental conditions and constrains.


Asunto(s)
Crioprotectores/química , Crioprotectores/aislamiento & purificación , Filtración/métodos , Adulto , Sistema Libre de Células/química , Eritrocitos/química , Filtración/instrumentación , Humanos , Modelos Teóricos , Reproducibilidad de los Resultados
12.
Artículo en Inglés | MEDLINE | ID: mdl-34206732

RESUMEN

To assess the effectiveness of the containment strategies proposed in Japan, an SEIAQR (susceptible-exposed-infected-asymptomatic-quarantined-recovered) model was established to simulate the transmission of COVID-19. We divided the spread of COVID-19 in Japan into different stages based on policies. The effective reproduction number Re and the transmission parameters were determined to evaluate the measures conducted by the Japanese Government during these periods. On 7 April 2020, the Japanese authority declared a state of emergency to control the rapid development of the pandemic. Based on the simulation results, the spread of COVID-19 in Japan can be inhibited by containment actions during the state of emergency. The effective reproduction number Re reduced from 1.99 (before the state of emergency) to 0.92 (after the state of emergency). The transmission parameters were fitted and characterized with quantifiable variables including the ratio of untracked cases, the PCR test index and the proportion of COCOA app users (official contact confirming application). The impact of these variables on the control of COVID-19 was investigated in the modelling analysis. On 8 January 2021, the Japanese Government declared another state of emergency. The simulated results demonstrated that the spread could be controlled in May by keeping the same strategies. A higher intensity of PCR testing was suggested, and a larger proportion of COCOA app users should reduce the final number of infections and the time needed to control the spread of COVID-19.


Asunto(s)
COVID-19 , Humanos , Japón , Pandemias , Cuarentena , SARS-CoV-2
13.
Cytotherapy ; 12(2): 161-9, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19929459

RESUMEN

BACKGROUND AIMS: An optimal cooling rate is one of the critical factors influencing the survival of cells during cryopreservation. We describe a novel device, called the box-in-box, that has been developed for optimal cryopreservation of human hematopoietic stem cells (HSC). METHODS: This work presents the design of the device, a mathematical formulation describing the expected temperature histories of samples during the freezing process, along with actual experimental results of thermal profile tests. In experiments, when the box-in-box device was transferred from room temperature to a -80 degrees C freezer, a cooling rate of -1 to -3.5 degrees C/min, which has been widely used for the cryopreservation of HSC, was achieved. In order to evaluate this device further, HSC cryopreservation was compared between the box-in-box device and a commercially available controlled-rate freezer (CryoMed). RESULTS: The experimental data, including total cell population and CD34(+) hematopoietic progenitor cell recovery rates, viability and cell culture colony assays, showed that the box-in-box worked as well as the CryoMed instrument. There was no significant difference in either survival rate or the culture/colony outcome between the two devices. CONCLUSIONS: The box-in-box device can work as a cheap, durable, reliable and maintenance-free instrument for the cryopreservation of HSC. This concept of a box-in-box may also be adapted to other cooling rates to support cryopreservation of a wide variety of tissues and cells.


Asunto(s)
Frío , Criopreservación/economía , Criopreservación/instrumentación , Células Madre Hematopoyéticas/citología , Antígenos CD34/metabolismo , Supervivencia Celular , Ensayo de Unidades Formadoras de Colonias , Criopreservación/métodos , Células Precursoras Eritroides/citología , Células Progenitoras de Granulocitos y Macrófagos/citología , Humanos , Modelos Biológicos
14.
Biopreserv Biobank ; 18(6): 570-580, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33320734

RESUMEN

The coronavirus disease 2019 (COVID-19) is an ongoing global pandemic caused by severe acute respiratory syndrome coronavirus 2. During the past 10 months, COVID-19 has killed over 1 million people worldwide. Under this global crisis, data sharing and management of the COVID-19 information are urgently needed and critical for researchers, epidemiologists, physicians, bioengineers, funding agencies, and governments to work together in developing new vaccines, drugs, methods, therapeutics, and strategies for the prevention and treatment of this deadly and rapidly spreading disease. The COVID-19 pandemic information includes the database of COVID-19-patient biospecimen resources in hospitals or biorepositories, electronic patient health records, ongoing clinical trials and research results on this disease, policies, guidelines, and regulations related to COVID-19, and the COVID-19 outbreak tracking records, and so on. A study of the current management and data-sharing approaches, tools, software, network, and internet systems developed in the United States is conducted in this article. Based on this study, it is revealed that the existing data-sharing and management systems are facing many big challenges and problems associated with data decentralization, inconsistencies, security and legal issues, limited financial support, international communications, standardization, and globalization. To overcome and solve these problems, several integrated platform models for national and international data-sharing and management are developed and proposed in this article to meet the unprecedented need and demand for COVID-19 pandemic information sharing and research worldwide.


Asunto(s)
COVID-19/epidemiología , Registros Electrónicos de Salud , Difusión de la Información , Pandemias , SARS-CoV-2 , Programas Informáticos , COVID-19/terapia , Humanos , Estados Unidos/epidemiología
15.
Biopreserv Biobank ; 18(6): 511-516, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33290126

RESUMEN

Biobanking has been playing a crucial role in the development of new vaccines, drugs, biotechnology, and therapeutics for the prevention and treatment of a wide range of human diseases. This puts biobanks at the forefront of responding to the ongoing worldwide outbreak of the severe pandemic, coronavirus disease 2019 (COVID-19). The leading public health institutions around the world have developed and established interim policies and guidelines for researchers and biobank staff to handle the infectious biospecimens safely and adequately from COVID-19 patients. A study of these important and complementary policies and guidelines is conducted in this study. It should be emphasized that the COVID-19 biospecimens must be collected, processed, and preserved by trained personnel equipped with right personal protective equipment to prevent the transmission of the coronavirus and ensure the specimen quality for testing and research. Six of the leading global public health organizations or institutions included in this study are the World Health Organization, the Pan American Health Organization, the U.S. Centers for Disease Control and Prevention, the Public Health England, the U.S. Food and Drug Administration, and the Office of Research at the University of California, San Francisco. In conclusion, following the recommended guidance and policies with extreme precautions is essential to ensure the quality of the collected COVID-19 biospecimens and accuracy of the conducted research or treatment, and prevent any possible transmission. Efforts from cryobiologist and biobanking engineers to optimize the protocol of COVID-19 biospecimen cryopreservation and develop the user-friendly and cost-effective devices are urgently required to meet the urgent and increased needs in the specimen biobanking and transportation.


Asunto(s)
Bancos de Muestras Biológicas , Investigación Biomédica , COVID-19/epidemiología , Pandemias , SARS-CoV-2 , Manejo de Especímenes , Humanos , Guías de Práctica Clínica como Asunto
17.
Micromachines (Basel) ; 10(12)2019 Nov 29.
Artículo en Inglés | MEDLINE | ID: mdl-31795446

RESUMEN

The Jurkat cell is an immortalized line of human acute lymphocyte leukemia cells that is widely used in the study of adoptive cell therapy, a novel treatment of several advanced forms of cancer. The ability to transport water and solutes across the cell membrane under different temperatures is an important factor for deciding the specific protocol for cryopreservation of the Jurkat cell. In this study we propose a comprehensive process for determination of membrane transport properties of Jurkat cell. using a novel microfluidic controlled single cell-trapping system. The osmotic behavior of an individual Jurkat cell to water and dimethyl sulfoxide (DMSO), a commonly used cryoprotective agent (CPA), under constant temperature, was recorded under a microscope utilizing the modified microfluidic system. The images of the Jurkat cell under osmotic change were processed to obtain a relationship between cell volume change and time. The experimental results were fitted using a two-parameter transport numeric model to calculate the Jurkat cell membrane permeability to water and DMSO at room temperature (22 °C). This model and the calculated parameters can help scientists optimize the cryopreservation protocol for any cell type with optimal cryoprotective agents and cooling rate for future experiments.

18.
PLoS One ; 13(7): e0200653, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30059507

RESUMEN

BACKGROUND: Cryopreservation of leukocytes isolated from the cervicovaginal and colorectal mucosa is useful for the study of cellular immunity (see Hughes SM et al. PLOS ONE 2016). However, some questions about mucosal biology and sexually transmitted infections are better addressed with intact mucosal tissue, for which there is no standard cryopreservation protocol. METHODS AND FINDINGS: To find an optimal preservation protocol for mucosal tissues, we tested slow cooling (1°C/min) with 10% dimethylsulfoxide (designated "cryopreservation") and fast cooling (plunge in liquid nitrogen) with 20% dimethylsulfoxide and 20% ethylene glycol ("vitrification"). We compared fresh and preserved human cervicovaginal and colorectal tissues in a range of assays, including metabolic activity, human immunodeficiency virus infection, cell phenotype, tissue structure by hematoxylin-and-eosin staining, cell number and viability, production of cytokines, and microbicide drug concentrations. Metabolic activity, HIV infectability, and tissue structure were similar in cryopreserved and vitrified vaginal tissues. However, vitrification led to poor cell recovery from the colorectal mucosa, with 90% fewer cells recovered after isolation from vitrified colorectal tissues than from cryopreserved. HIV infection rates were similar for fresh and cryopreserved ectocervical tissues, whereas cryopreserved colorectal tissues were less easily infected than fresh tissues (hazard ratio 0.7 [95% confidence interval 0.4, 1.2]). Finally, we compared isolation of cells before and after cryopreservation. Cell recoveries were higher when cells were isolated after freezing and thawing (71% [59-84%]) than before (50% [38-62%]). Cellular function was similar to fresh tissue in both cases. Microbicide drug concentrations were lower in cryopreserved explants compared to fresh ones. CONCLUSIONS: Cryopreservation of intact cervicovaginal and colorectal tissues with dimethylsulfoxide works well in a range of assays, while the utility of vitrification is more limited. Cell yields are higher from cryopreserved intact tissue pieces than from thawed cryopreserved single cell suspensions isolated before freezing, but T cell functions are similar.


Asunto(s)
Bioensayo/métodos , Criopreservación/métodos , Crioprotectores/química , Membrana Mucosa , Vitrificación , Cuello del Útero , Dimetilsulfóxido/química , Femenino , VIH/patogenicidad , Infecciones por VIH/transmisión , Infecciones por VIH/virología , Humanos , Intestino Grueso , Linfocitos T , Vagina
20.
Biopreserv Biobank ; 15(5): 404-409, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-28783479

RESUMEN

In the rewarming process during cryopreservation, preventing ice recrystallization and thermal stress is important, especially for large tissues and organs. Uniform and rapid heating is essential in ameliorating the problem and maintaining the viability of cryopreserved biological samples. Currently, the most promising method is heating by application of electromagnetic (EM) waves, the effectiveness of which is dependent on the dielectric properties (DP) of the cryopreserved materials. In this work, the cavity perturbation method was adopted to measure the DP of cryoprotectant solutions. Based on the values of DP, the cryoprotectant solutions most amenable to EM heating can be identified. A system composed of a rectangular resonant cavity, a network analyzer, and a fiber optic temperature meter was implemented for the measurement. The DP of three cryoprotectant solutions during cooling to -80°C were measured and presented. The data can be used to optimize the rewarming process with the numerical method. The results show that a cryoprotectant solution consisting of 41% (w/v) dimethyl sulfoxide and 6% (w/v) polyvinylpyrrolidone has the highest dielectric loss for EM rewarming among the tested solutions. In addition, the developed DP measurement system could not only improve the EM heating in cryopreservation but also benefit hyperthermia or other therapies associated with EM waves.


Asunto(s)
Crioprotectores/química , Recalentamiento/métodos , Criopreservación , Fenómenos Electromagnéticos , Humanos , Conservación de Tejido
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