In vivo study of porous NiTi cryotweezers for bone tissue cryotherapy

This study examined the effects of liquid nitrogen vapor on osteogenesis in the rabbit femur. Cryotweezers made of porous nickel titanium alloy (nitinol or NiTi) obtained by self-propagating high temperature synthesis were used in this experiment. The porous structure of the cryotweezers allows them to hold up to 10 g of liquid nitrogen after being immersed for 2 min, which completely evaporates after 160 s. To study the effects of liquid nitrogen evaporation on osteogenesis, a rabbit femur was perforated. The formed holes were subjected to cryotherapy with varying exposure times. It was found that a 3 s exposure time stimulates osteogenesis, which was manifested in a greater number of osteoblasts in the regenerate compared to the control sample without liquid nitrogen. It was observed that increasing the exposure to 6, 9 or 12 s had a destructive effect, to varying degrees. The most severe damage was exerted by a 12 s exposure, which resulted in the formation of osteonecrosis areas. In the samples exposed to 6 and 9 s of cryotherapy, destruction of the cytoplasm of osteocytes and osteoclasts was observed.

Cryopreservation of sessile oak (Quercus petraea (Matt.) Liebl.) plumules using aluminium cryo-plates: influence of cryoprotection and drying

BACKGROUND QUERCUS: seeds that are recalcitrant to desiccation and freezing temperatures cannot be stored in gene banks under conventional conditions. However, the germplasm of some recalcitrant seeded species can be stored in liquid nitrogen (-196 °C). Unfortunately, for many species, among them for almost the whole genus Quercus, an effective cryostorage method is still unknown. In this study, we propose a successful cryostorage protocol for Quercus petraea (Matt.) Liebl. germplasm using plumules (a shoot apical meristem of an embryo) frozen on aluminium cryo-plates. RESULTS: The plumules isolated from the acorns of ten provenances were prestored in 0.5 M sucrose solution (for 18 h). To form alginate beads (one plumule per bead), the plumules were placed in the wells of a cryo-plate and embedded in calcium alginate gel. For cryoprotection, the encapsulated plumules were immersed in cryoprotectant solution containing 2.0 M glycerol and different concentrations of sucrose (0.8-1.2 M) for 40 min at 25 °C and desiccated under a laminar flow cabinet for 1.0-4.0 h. Cryo-plates with plumules were directly immersed in liquid nitrogen and then cryostored for 30 min. For rewarming, cryo-plates with plumules were immersed in 1.0 M sucrose solution and rehydrated for 15 min at 25 °C. Survival rates varied from 25.8 to 83.4 were achieved after cryoprotection in 1.0 M sucrose solution and the drying of plumules for 2 h. The in vitro regrowth rate of cryopreserved plumules varied among provenances and was 26-77%. CONCLUSIONS: This study presents, for the first time, a successful, simple and effective protocol for the cryopreservation of Q. petraea germplasm that could be used in gene banks. The experiment was successfully repeated on seeds from various provenances, each yielding similar, good results. However, seed quality and storage time after harvesting are important factors in plumule regrowth after cryopreservation.

EtOH-LN cryoembedding workflow to minimize freezing artifact in frozen tissues: A pilot study in preparing tissues compatible with mass spectrometry-based spatial proteomics application

Coolant-assisted liquid nitrogen (LN) flash freezing of frozen tissues has been widely adopted to preserve tissue morphology for histopathological annotations in mass spectrometry-based spatial proteomics techniques. However, existing coolants pose health risks upon inhalation and are expensive. To overcome this challenge, we present our pilot study by introducing the EtOH-LN workflow, which demonstrates the feasibility of using 95 % ethanol as a safer and easily accessible alternative to existing coolants for LN-based cryoembedding of frozen tissues. Our study reveals that both the EtOH-LN and LN-only cryoembedding workflows exhibit significantly reduced freezing artifacts compared to cryoembedding in cryostat (p < 0.005), while EtOH-LN (SD = 0.56) generates more consistent results compared to LN-only (SD = 1.29). We have modified a previously reported morphology restoration method to incorporate the EtOH-LN workflow, which successfully restored the tissue architecture from freezing artifacts (p < 0.05). Additional studies are required to validate the impact of the EtOH-LN workflow on the molecular profiles of tissues.

Combination of frozen autograft produced with liquid nitrogen and total hip replacement as a bone recycle reconstruction in pelvic osteosarcoma resection type 2: A case report

INTRODUCTION

Pelvic osteosarcoma remains a challenge for orthopedic surgeons to manage. However, recent advances giving various options to get a more effective reconstruction method. We present bone recycle reconstruction using a combination of frozen autograft and total hip replacement (THR) following extraarticular resection type II of pelvic osteosarcoma.

PRESENTATION OF CASE

A 31-year-old female presented with pain in sitting and standing positions with no lump noted in the right hip joint for 11 months. Physical examination showed a palpable mass with indistinct margin in the inner groin area, with a limited range of motion. Histopathological examination confirmed small-cell osteosarcomaa. Extraarticular pelvic resection type 2 was performed followed by cryo-procedure using liquid nitrogen to produce frozen autograft. The graft was implanted and fixated with 3 reconstruction plates and screws, followed by THR. Postoperative plain radiographs showed the graft and implants were well-placed and fixated. There was no postoperative complication, local recurrence, or metastasis observed. The patient started to sit in the wheelchair without pain and walk using crutches.

DISCUSSION

Following resection of the hemi pelvic, various alternative reconstruction procedures such as pseudoarthrosis, arthrodesis, mega prostheses, massive allograft, and cryosurgery were attempted, but still dissatisfying which results in numerous complications. Expensive cost reconstruction makes it difficult to be performed in developing country like Indonesia.

CONCLUSION

A combination of frozen autograft and THR following pelvic resection achieve a cost-effective and desirable outcome which gives a good result in short-term follow-up. It could be a promising option for managing oncology cases.

Validation of electrodeposited 241Am alpha-particle sources for use in liquified gas detectors at cryogenic temperatures

This paper describes a procedure for the validation of alpha-particle sources (exempt unsealed sources) to be used in experimental setups with liquefied gases at cryogenic temperatures (down to -196 °C) and high vacuum. These setups are of interest for the development and characterization of neutrino and dark matter detectors based on liquid argon, among others. Due to the high purity requirements, the sources have to withstand high vacuum and cryogenic temperatures for extended periods. The validation procedure has been applied to 241Am sources produced by electrodeposition.

High regrowth of potato crop wild relative genotypes after cryogenic storage

Potatoes are consumed by millions of people and are the survival food in several countries. Cultivated varieties of potato (Solanum tubersosum L.) are results of selection and crossing of many wild species. Only 8-13% of wild potato species used for food are preserved by either in situ or ex situ methods. The U.S. National Potato Germplasm Collection maintains over 5900 accessions, of which 75% are crop wild relatives (CWR). The objective of the study was to investigate regrowth of cryogenically stored clonal propagules (shoot tips) of selected CWR accessions maintained in the collection. Sixty-nine accessions from 30 Solanum species and six accessions that are not yet assigned to a species were cryopreserved by a droplet vitrification method at the NLGRP. The post cryopreservation regrowth varied from 40 to 100% (average 68%) but was not significantly different between the tested accessions. Regrowth of six accessions tested after 10 years of cryogenic storage was between 35 and 90% (average 66%) and was significantly different from their initial regrowth (average 87%); the largest viability loss was in S. condolleanum; but for the other five accessions the regrowth was between 45 and 90% (average 72%) and suggested at least 10 years of successful storage in LN was possible. Twelve potato wild species cryopreserved in this study were reported in literature as important for developing cultivated varieties for changed weather conditions.

Optimizing the viability, stability, and potency of Buffy coat isolated T cells for homologous dendritic cell co-cultures: A method for handling and preservation

The utilization of T cells is becoming increasingly prominent in both clinical and research domains. However, the need to optimize preservation methodologies for extended periods of time remains unmet. To address this issue, we have developed a protocol for the handling and preservation of T cells that facilitates successful donor homologous co-cultures with dendritic cells (DCs), and preserves the cells for subsequent testing. Our method enhances experimental efficiency by reducing time and effort, and simplifying the use of T cells in mono or co-cultures. Our T cell handling and preservation methodology demonstrates the stability and viability of these cells in co-cultures, with viability exceeding 93% before and after liquid nitrogen preservation. Additionally, the preserved cells display no unspecific activation, as evidenced by the unaltered expression of the T cell activation marker CD25. The proliferation profile of preserved T cells used in DC-T cell co-cultures, stimulated by lipopolysaccharide (LPS)-activated DCs, attests to the potency and ability of these cells to interact and proliferate. These findings underscore the efficacy of our handling and preservation methodology in maintaining T cell viability and stability. Preserving donor T cells not only reduces the inconvenience of repeated blood donations but also enhances accessibility to a particular population of T cells for experimental or clinical applications, such as chimeric antigen receptor T cells.

Cryogenic storage increases the longevity of butternut (Juglans cinerea, L.) seed embryogenic axes

Butternut (Juglans cinerea L.), a species listed as endangered, is currently undergoing rapid decline due to habitat loss and the introduction of Ophiognomonia clavigignenti-juglandacearum, a non-native pathogen causing butternut canker. The decline of butternut has led to the development of cryobiological methods for the ex-situ conservation of the species since viability is not maintained using conventional methods. In this study, we assess the survivability and growth of butternut embryogenic axes into plantlets after 7 years of cryopreservation. Results show that cryopreservation is a highly effective method for the long-term storage of embryogenic axes since both survival and subsequent acclimatization into plantlets was successful with an average of 76% survival and 71% acclimatization, respectively. These results surpass the actual duration viability for non-cryogenic storage of butternut seed and we hope that future testing will result in longer term success of this cryobiological method and provide much needed germplasm for future restoration.

Thallium removal from wastewater using sulfidized zero-valent manganese: Effects of sulfidation method and liquid nitrogen pretreatment

Zero-valent manganese (ZVMn) possesses high reducibility in theory, while sulfide exhibits strong affinity towards a variety of heavy metals owing to the low solubility of metal sulfides. Yet the performance and mechanisms on using sulfidized zero-valent manganese (SZVMn) to remove thallium (Tl) from wastewater still remain unclear. In this study, the performance of Tl(I) removal using SZVMn synthesized by borohydrides reduction followed by sulfides modification, with and without liquid nitrogen treatment, was compared and the mechanism behind was investigated. The results show that at a S/Mn molar ratio of 1.0, liquid nitrogen modified SZVMn (LSZVMn) possessed more interior channels and pores than SZVMn, with 65.3% higher specific surface area and 73.7% higher porosity, leading to 6.4-8.1% improvement in adsorption of Tl(I) at pH 4-10. LSZVMn showed effectiveness and robustness in Tl(I) removal in the presence of co-existing ions up to 0.1 M. The adsorption of Tl(I) conformed to the pseudo-1st-order kinetic model, and followed the Langmuir isothermal model, with the maximum Tl adsorption capacity of 264.9 mg·g^-1 at 288 K. The mechanism of Tl(I) removal with SZVMn was found to include sulfidation-induced precipitation, manganese reduction, surface complexation, and electrostatic attraction. The liquid nitrogen pretreatment embrittled and cracked the outer shell of S/Mn compounds, resulted in a highly hierarchical structure, enhancing the manganese reduction and improving the Tl(I) removal. Based on the above results, the SZVMn and its liquid nitrogen-modified derivatives are novel and effective environmental materials for Tl(I) removal from wastewater, and the application of SZVMn to the removal of other pollutants merits investigation in future study.

Rapid Freezing of Skeletal and Cardiac Muscles Using Isopentane Cooled with Liquid Nitrogen and Tragacanth Gum for Histological, Genetic, and Protein Expression Studies

Histological and molecular genetic evaluation of skeletal and cardiac muscles is an indispensable part of understanding muscle biology and the pathology of muscle disorders. Proper processing of the muscle tissue is a prerequisite for optimal evaluation. However, the processing of skeletal muscle samples often comes with many challenges. One of the commonly used methods of frozen tissue preparation involves optimal cutting temperature compound (OCT compound) embedding. This method is considered optimal for the processing of most of the routinely studied tissue samples. However, the processing of skeletal muscle samples using this method is often unsuitable as it causes artifacts and low DNA, RNA, and protein yield and quality due to the slow freezing of skeletal muscle tissues that allows ice crystals to form. One of the most suitable methods for skeletal muscle tissue processing for histological, genetic, and molecular studies is rapid freezing of freshly collected tissue samples using isopentane cooled with liquid nitrogen and tragacanth gum, which provides distinct advantages in consuming less time, preserving the cell morphology, and helping higher nucleic acids and protein yields. This chapter describes a protocol for rapid freezing of freshly collected skeletal muscle tissues using isopentane pre-chilled with liquid nitrogen and tragacanth gum. Skeletal muscle tissue samples processed using this protocol can be used for histological and immunological staining investigations and studies requiring DNA, RNA, and proteins from these tissues.

Tissue Fixation and Processing for the Histological Identification of Lipids

Lipids are a heterogeneous group of substances characterized by their solubility in organic solvents and insolubility in water. Lipids can be found as normal components of different tissues and organs, and they can be affected by several pathological conditions. The histochemical identification of lipids plays an important role in the histopathological diagnosis and research, but successful staining depends on adequate fixation and processing of the tissue. Here we describe methods to fix, cryoprotect, and process tissue samples for the histochemical identification of lipids in frozen or paraffin-embedded tissues.

65% Parahydrogen from a liquid nitrogen cooled generator

The isomeric enrichment of parahydrogen (pH₂) gas is readily accomplished by lowering the gas temperature in the presence of a catalyst. This enrichment is often pursued at two distinct temperatures: ∼51% pH₂ is generated at liquid nitrogen temperatures (77 K), while nearly 100% pH₂ can be produced at 20 K. While the liquid nitrogen cooled generator is attractive due to the low cost of entry, there are benefits to having access to greater than 51% pH₂ for enhanced NMR applications. In this work, we introduce a low-cost modification to an existing laboratory-constructed liquid nitrogen cooled pH₂ generator that provides ∼ 65% pH₂. This modification takes advantage of vacuum-mediated boiling point suppression of liquid nitrogen, allowing the temperature of the liquid to be lowered from 77 K to nitrogen's triple point of 63 K. The reduced temperature allowed for the generation of parahydrogen fractions of 63-67% at gas flow rates from 20 to 1000 standard cubic centimeters per minute. We compare this to equivalent experiments that did not utilize the temperature-lowering effects of pressure reduction; these controls generally maintained pH₂ fractions of ∼ 50%. All results (experimental and control) agree with the theoretically expected parahydrogen generation at these temperatures. This straightforward modification to an existing pH₂ generator may be of interest to a broad range of scientists involved with parahydrogen research by introducing a simple and low-cost entryway to increased pH₂ fractions using a conventional liquid nitrogen cooled generator.

Effects of sampling and storage procedures on 16S rDNA amplicon sequencing results of kelp microbiomes

Brown macroalgae, including the kelp Saccharina latissima, are of both ecological and increasing economic interest. Together with their microbiota, these organisms form a singular entity, the holobiont. Sampling campaigns are required to study the microbiome of algae in natural populations, but freezing samples in liquid nitrogen is complex in the field, particularly at remote locations. Here we tested two simple alternative methods for sampling the microbial diversity associated with the kelp S. latissima: silica gel conservation of tissue and swab samples preserved in DNA/RNA shield solution. We used these techniques to compare apex and meristem samples from Roscoff (Brittany, France) and evaluated their impact on the results of 16S rDNA metabarcoding experiments. Both methods were able to separate apex and meristem microbiomes, and the results were concordant with results obtained for flash-frozen samples. However, differences were observed for several rare genera and ASVs, and the detection of contaminant sequences in the silica gel-preserved samples underline the importance of including blank samples for this method. Globally, our results confirm that the silica gel technique and swabbing combined with DNA/RNA shield preservation are valid alternatives to liquid nitrogen preservation when sampling brown macroalgae in the field. However, they also underline that, regardless of the method, caution should be taken when interpreting data on rare sequences.

Does longer storage of blastocysts with equal grades in a cryopreserved state affect the perinatal outcomes?

AIM

Although mammalian embryos could be preserved in liquid nitrogen for thousands of years in theoretical models, the viability of cryopreserved blastocyst with varying grades remains to be speculated. In this study, we aimed to determine whether the longer storage time of blastocysts with equal grades could negatively affect the perinatal outcomes.

MATERIALS AND METHODS

Single vitrified-warmed blastocyst was divided into four grades (AA, AB/BA, BB, BC/CB) according to the blastocyst score when freezing, and each grade of blastocyst was categorized into four storage duration categories: 28 days-1 year, 1-3 years, 3-5 years, and ≥5 years. Then the perinatal outcomes with different storage time were analyzed.

RESULTS

Our results revealed that for blastocysts with the same grade, the length of storage time had no statistical effect on blastocyst survival rate, clinical pregnancy/implantation rate, live birth rate, and abortion rate. In addition, more advanced developmental blastocyst could obtain better pregnancy outcomes regardless of the cryopreservation length. Similar neonatal outcomes were obtained over time.

CONCLUSIONS

Cryopreservation time could not negatively affect the perinatal outcomes of blastocysts with equal grades. Efficient blastocyst cryopreservation technology by vitrification can help older women obtain high-quality embryos at a young age.

Comparative Analysis of the Major Metabolites of Ukrainian Saffron Samples by HPLC

Crocus sativus L. is one of the most valuable crops, which stigmas are used as the food supplement and herbal medicine. In Ukraine, the cultivation of C. sativus began in 2015, and in this regard, it became possible to conduct a comparative content analysis of the major metabolites (crocin, picrocrocin, safranal) using the validated HPLC method in the stigmas from the different country regions. The grinding technique of Crocus stigmas in liquid nitrogen was used for the first time, which influenced an increase in the yield of trans-crocetin bis(β-D-gentiobiosyl) ester in 3.5 times compared with a normal grinding. Samples from the northeastern regions of cultivation such as Zaporizhia and Chernigiv had the higher amount of crocin (205 and 226 mg/g, respectively), while in the samples of the southwestern region the decrease of the amount of crocin was observed (180 mg/g and less), which was due to the climatic features of the country. These results can be utilized in the pharmaceutical and food industries for creating food additives for human nutrition.

UV radiation dose in real time with a cryogenic SiPM using Monte Carlo-Geant4 simulation

At the moment, there is no method that allows the user to calculate the dose of UV radiation during the liquid nitrogen (LN2) sterilization process while complying with quality control regulations. This article describes a simulating method using Geant4 to obtain the dose of UV radiation in real-time with a cryogenic Silicon PhotoMultipliers (SiPM) inside the LN2 container. The results present the zone of minimum UV radiation and the estimation of the radiation dose with a cryogenic SiPM, located in the minimum zone to certify the absence of microorganisms in the LN2.

Case report on metastatic pelvic bone tumor treated with frozen autograft by liquid nitrogen

INTRODUCTION AND IMPORTANCE

Frozen autograft recycling has been used for biological reconstruction of bone defects following tumor excision, more commonly in extremities. We report on the histological outcome of a pelvic recycled frozen autograft.

CASE PRESENTATION

We investigated the pelvic frozen autograft removed in 2 years and 8 months after surgery because of soft tissue recurrence in pelvic floor. The autograft bone showed no evidence of revitalization and was non-viable with patchy inflammation, and no residual tumor. There was only fibrous union but the autograft bone remained mechanically stable.

CLINICAL DISCUSSION

We confirmed the clearance of tumor cells with the treatment with liquid nitrogen. The union at the host-graft junction might be affected by the previous radiotherapy, the presence of infection, the small contact area limited by the anatomy, and the inadequate compression across the osteotomy interface with the fixation.

CONCLUSION

Frozen autograft treated by liquid nitrogen can be used safely for biological reconstructions after pelvic tumor excision.

Cryopreservation and low-temperature storage of seeds of Tillandsia species (Bromeliaceae) with ornamental potential

Tillandsia (Bromeliaceae) species have high endemism, and due to their strong ornamental potential, predatory extraction is threatening the extinction or drastic population reduction of many of them. In light of this scenario, it is necessary to find strategies for the conservation of these endangered species. The objective of this study was to evaluate two seed preservation strategies (freezing at - 5 °C and cryopreservation at - 196 °C) for 20 Tillandsia species occurring in the state of Bahia. We initially evaluated the morphometry, thousand-seed weight, and water content, followed by tests of germination and desiccation. After selecting the best result of the germination test (Germitest paper and incubation at 30 °C) and desiccation (3 h on silica gel), we established conservation tests utilizing two temperatures (freezing at - 5 °C and liquid nitrogen at - 196 °C), with storage times of 1, 7, 30, 180 and 450 days. Analysis of variance indicated that the 20 species had different behaviors when submitted to the two temperatures and different storage times. After 450 days there was a reduction in the germination percentage and germination speed index (GSI) of all the species studied when the seeds were preserved in the freezer. The storage in liquid nitrogen was efficient for the preservation of Tillandsia seeds when dried to a moisture content of approximately 7%. Our results support the establishment of a cryobank for Tillandsia to conserve these endemic species.

Optimizing the spray parameters of a cryospray process

Smaller spray zone of single-hole nozzle (SHN) constrains cryospray as a treatment method suitable for lesions having diameter larger than 15 mm on the skin surface. The present study is an attempt to resolve this issue, through the improvement in conventional technique of spraying liquid nitrogen on cancerous lesion. A multi-hole nozzle (MHN) with 5 holes is fabricated to demarcate the variation in outcome when cryogen is sprayed through customised MHN instead of conventional SHN. Special emphasis is placed on reducing the number of sitting required for completion of treatment and increasing the feasibility of cryospray process for larger lesions. Commercial SHN having a hole diameter of 0.8 mm is selected to compare results with the customised MHN having 5 holes of 0.8 mm diameter (4 holes are arranged in a circle of radius 2 mm around the central hole). Single freeze-thaw cycle is carried out to spray liquid nitrogen on tissue mimicking gel. Temperature profile accessed through infrared images advocates that lethal area formed through application of MHN is twice larger than the lethal area formed through the application of SHN on the surface of gel for same spraying distance (z). Thermocouples placed at various locations strengthen the fact that higher cooling rate (CR) corresponding to MHN ensures 15 mm spread of necrotic zone from the centre of spray (CS) and up to a depth of 2 mm from the gel surface while in case of SHN, it is limited to the vicinity of CS. On the basis of observations made through thermal images and digital images, it can be said that the ratio of lateral spread to penetration depth of ice ball remains almost same for SHN and MHN. However, the lateral spread of ice ball formed through the application of MHN is twice larger than SHN while the axial depth of ice ball does not record such increment. This reflects that MHN provides more destruction to superficial skin than SHN. Among the three spraying distances selected (i.e. z = 13 mm, 18 mm and 23 mm), the most optimised spraying distance (z) for MHN is also explored in this study. It has been found that cryoablation is not inversely proportional to the spraying distance. Spraying distance of z = 18 mm provided the most optimised result in terms of cryoablation.

Revision surgery for instrumentation failure after total en bloc spondylectomy: a retrospective case series

Background

There have been several reports of instrumentation failure after three-column resections such as total en bloc spondylectomy (TES) for spinal tumors; however, clinical outcomes of revision surgery for instrumentation failure after TES are seldom reported. Therefore, this study assessed the clinical outcomes of revision surgery for instrumentation failure after TES.

Methods

This study employed a retrospective case series in a single center and included 61 patients with spinal tumors who underwent TES between 2010 and 2015 and were followed up for > 2 years. Instrumentation failure rate, back pain, neurological deterioration, ambulatory status, operation time, blood loss, complications, bone fusion after revision surgery, and re-instrumentation failure were assessed. Data were collected on back pain, neurological deterioration, ambulatory status, and management for patients with instrumentation failure, and we documented radiological bone fusion and re-instrumentation failure in cases followed up for > 2 years after revision surgery.

Results

Of the 61 patients, 26 (42.6%) experienced instrumentation failure at an average of 32 (range, 11–92) months after TES. Of these, 23 underwent revision surgery. The average operation time and intraoperative blood loss were 204 min and 97 ml, respectively. Including the six patients who were unable to walk after instrumentation failure, all patients were able to walk after revision surgery. Perioperative complications of reoperation were surgical site infection (n = 2) and delayed wound healing (n = 1). At the final follow-up, bone fusion was observed in all patients. No re-instrumentation failure was recorded.

Conclusion

Bone fusion was achieved by revision surgery using the posterior approach alone.

Aseptic Cryoprotectant-Free Vitrification of Human Spermatozoa by Direct Dropping into a Cooling Agent

Spermatozoa cryopreservation is used for the management of infertility and some other medical conditions. Routinely applied cryopreservation techniques depend on permeating cryoprotectants and relatively slow freezing rates. Cryoprotectant-free vitrification is an alternative and cost-effective method that is based on rapid cooling of spermatozoa by direct plunging into a cooling agent to prevent lethal intracellular ice crystallization and the detrimental effects of high salt concentrations. One of the problems with this technique is that full sterilization of commercially produced liquid nitrogen, which could be contaminated with different pathogens, is not possible. Here we use a benchtop device for the production of sterile liquid air with the same temperature as liquid nitrogen (-195.7 °C). This has been used to develop aseptic technology for cryoprotectant-free vitrification of human spermatozoa.

Human sperm vitrification: the state of the art

Sperm cryopreservation has been widely used in assisted reproductive technology (ART) and has resulted in millions of live births. Two principal approaches have been adopted: conventional (slow) freezing and vitrification. As a traditional technique, slow freezing has been successfully employed and widely used at ART clinics whereas the latter, a process to solidify liquid into an amorphous or glassy state, may become a faster alternative method of sperm cryopreservation with significant benefits in regard to simple equipment and applicability to fertility centers. Sperm vitrification has its own limitations. Firstly, small volume of load is usually plunged to liquid nitrogen to achieve high cooling rate, which makes large volume sample cryopreservation less feasible. Secondly, direct contact with liquid nitrogen increases the potential risk of contamination. Recently, new carriers have been developed to facilitate improved control over the volume and speed, and new strategies have been implemented to minimize the contamination risk. In summary, although sperm vitrification has not yet been applied in routine sperm cryopreservation, its potential as a standard procedure is growing.

Cryo-milling with spherical crystalline cellulose beads: A contamination-free and safety conscious technology

Crystalline cellulose is a common inactive pharmaceutical additive. If this material can also be used to construct beads for the wet milling of pharmaceutical compounds, it could possibly address issues related to wear and contamination associated with zirconia and polyethylene beads. In this study, the model drug phenytoin was milled with spherical crystalline cellulose (SCC) in liquid nitrogen. The particle size of the milled product was found to be comparable to that obtained using zirconia beads, verifying the feasibility of using SCC beads for this purpose. Using a design of experiment approach, the bead amount, agitation speed, and milling time were all determined to have a significant effect on the milled particle size, giving a D50 value as low as 0.3 μm. No breakage of the SCC beads was observed during the milling process in durability tests under conditions that will degrade spherical D-mannitol beads, showing that this material exhibits sufficient durability. In addition, the variation in elastic modulus between beads was minimal. Because SCC is commercially available and easy to handle, the present wet milling technique is considered to have potential applications to the manufacture of pharmaceuticals on an industrial scale, as it shows sufficient milling capability and durability.

Pedicle frozen autograft-prosthesis composite reconstructions for malignant bone tumors of the proximal femur

Background

Limb salvage surgery is becoming increasingly popular after tumor resection in the lower extremity. Biological reconstruction and use of megaprosthesis are main methods for malignant bone tumors of the proximal femur, which remain controversial due to short- and long-term complication in the proximal femur. Tumor-bearing bone treated by liquid nitrogen is one of biological reconstruction. This study aimed to evaluate the mid- and long-term functional outcomes and complications in patients treated with frozen autograft–prosthesis composite (FAPC) reconstructions in the proximal femur.

Methods

This retrospective study included 19 patients (10 women, 9 men) with malignant tumors of the proximal femur who underwent tumor-wide resection and FAPC reconstruction (mean age, 46 years; range, 9–77 years). The mean follow-up period of 69 months (range, 9–179 months). Functional outcomes, oncological outcome and complications were evaluated by Musculoskeletal Tumor Society score, clinical and radiological examinations.

Results

The overall survival rate was 68.4%, and the mean Musculoskeletal Tumor Society functional score was 26.4 points (88%). FAPC survival rates were 100 and 50% at 5 and 10 years, respectively. Five of the 19 patients (26%) had complications: 2 required prosthesis removal and 2 developed a deep infection around acetabular. Wear of the acetabulum occurred in 2 cases, while disease recurrence was occurred in 1 case. There were no cases of greater trochanter avulsion, obvious absorption around frozen bone, prosthesis loosening or leg length discrepancy.

Conclusions

Due to without femoral osteotomy, this technique features satisfactory functional outcome and provide biomechanical stability that is comparable to those of other methods of biological reconstruction or megaprosthesis.

Limb Salvage Using Liquid Nitrogen-Treated Tumour-Bearing Autograft: A Single Institutional Experience of 10 Patients

BACKGROUND

Many reconstruction methods have evolved to offer limb salvage surgery (LSS) to patients with musculoskeletal sarcomas. It can be achieved using endoprosthesis or biological reconstruction methods like allograft or autograft or a combination of both. In carefully selected patients, resected bone can be recycled and reimplanted after sterilisation using methods like irradiation, autoclaving, pasteurisation or liquid nitrogen.

METHODS

From 2010 to 2016, 10 patients with primary musculoskeletal sarcoma underwent limb salvage surgery (LSS) by wide resection of the tumour and reconstruction using recycled autograft treated with liquid nitrogen. Intercalary resection was carried out in six patients and intra-articular in four. The resected bone was dipped in liquid nitrogen for 25 min, thawed at room temperature for 15 min followed by dipping in vancomycin-mixed saline for 10 min. The recycled bone was re-implanted into its original site and stabilised with internal fixation.

RESULTS

At a mean follow-up period of 39.6 months (range 6-97 months), all patients had a good function (mean functional score of 80%) with no evidence of local recurrence in the re-implanted bone or otherwise. Union was achieved at 15 of the 16 osteotomy sites with a mean union time of 5.2 months (range 4-7 months) without any additional surgical interventions. In none of the patient, augmentation with vascularised/non-vascularised fibula was done. No complication like fracture of the autograft, implant failure or deep/superficial infection was reported in any patient.

CONCLUSION

Recycled tumour-bearing autograft after treatment with liquid nitrogen is an anatomical, cost-effective, relatively simpler and reliable technique for reconstruction of bone defect after resection in selective primary musculoskeletal sarcoma patients.

The process of bone regeneration from devitalization to revitalization after pedicle freezing with immunohistochemical and histological examination in rabbits

The pedicle freezing procedure by liquid nitrogen is a method for the reconstruction of tumor-bearing bone after malignant tumor resection. However, the regenerative mechanism of bone after the pedicle freezing procedure is unclear. We investigated the complete process from devitalization to revitalization of bone after the pedicle freezing procedure in 13 rabbits. After osteotomy the 5 mm distal femurs were immersed in liquid nitrogen, and the specimens were divided into frozen area and sub-frozen area. The bilateral femurs were harvested for evaluation of bone regeneration by histological and immunohistochemical examination (VEGF, CD31, BMP-2 and Runx2) from 1 week to 52 weeks. The diameter of operating femurs was compared with contralateral femurs from 6 weeks to 52 weeks. No viable cells could be found from 1 to 8 weeks in the frozen area, and a mean 1.83 cm necrotic range were detected in the sub-frozen area. The periosteal reaction, massive fibrous tissue and immature bone matrix invaded from the normal area to the necrotic area from 12 weeks. Subsequently, the necrotic bone was gradually replaced by newly formed bone by creeping substitution, with endochondral and intramembrane bone formation. The diameter of frozen femurs was significantly larger than the contralateral femur at the same period from 8 weeks to 52 weeks (P < 0.01). All immunohistochemical factors were positively expressed in both areas at different time points. The active osteoblasts and microvessel migrated from marrow cavity and periosteum into dead bone. This study suggested that the frozen bone not only provides a scaffold but also possesses excellent osteoinductive properties.

A New Perspective on Cryotherapy: Pathogen Elimination Using Plant Shoot Apical Meristem via Cryogenic Techniques

Plant pathogens cause different diseases on crops and industrial plant species that result in economic losses. Pathogen-free plant material has usually been obtained by traditional procedures such as meristem culture, thermotherapy, and chemotherapy. However, there are many limitations of these procedures such as mechanical challenges of meristem excision and low regeneration rate, low resistance to high temperatures, phytotoxicity, and mutagenic effects of the chemicals used in the procedures. Cryotherapy is a newly developed biotechnological tool that has been very effective in virus elimination from economically important plant species. This tool has overcome the abovementioned limitations. This chapter aims to highlight the importance of the cryogenic procedures (vitrification, encapsulation-vitrification, droplet vitrification, two-step freezing, dehydration, encapsulation-dehydration) in order to generate virus-free germplasm.

Cavitation dynamics in water at elevated temperatures and in liquid nitrogen at an ultrasonic horn tip

Understanding and predicting thermodynamic effects is crucial when the critical point temperature is close to the operating temperature of the fluid, like in cryogenics. Due to the extreme difficulties of experimental investigation, predicting of thermodynamic effects in cavitation often bases on data in liquids other than cryogenics. Most often used surrogate liquids are hot water or certain refrigerants, which are selected by a single fluid property, most commonly by the thermodynamic parameter ∑. The paper presents a systematic study of the cavitation dynamics in water at 20 °C, 40 °C, 60 °C, 80 °C and 100 °C and in addition in liquid nitrogen (LN2). Cavitation dynamics on a 4.8 mm (tip diameter) ultrasonic horn tip, which oscillated at 20 kHz was investigated by high-speed visualization at 300,000 frames per second (fps). Simultaneously acoustic emissions were recorded by a high frequency pressure transducer. Measurements were performed under variation of the acoustic power in a closed, insulated vessel, where pressure could be optionally set. The main purpose of the presented investigation is to determine whether hot water can act as a surrogate liquid to cryogenics. The results may implicate the future investigations and development of a new generation of rocket engines, which also feature the possibility of re-ignition while in orbit - understanding and predicting of cavitation behaviour is becoming a crucial part at the (liquid oxygen - LOX and liquid hydrogen - LH2) turbo-pump design.

Frozen dog spermatozoa are negatively affected during storage at -80, -21 and -8 ºC

Cryopreservation in liquid nitrogen (LN2) allows for semen to be stored for long periods of time while there is sustaining of sperm viability. In this study, there was assessment of effects induced by different storage temperatures on cryopreserved dog spermatozoa. After cryopreservation at -196 °C, sperm samples were transferred to storage conditions of -80, 21 or -8 °C. Sperm motility, morphology, viability, acrosome integrity, mitochondrial membrane potential and DNA fragmentation were determined in samples stored at -196 °C (evaluation time =0 h), and then after 12 h and 1, 4, 7 and 15 d of storage at 80, -21 and -8 °C. In samples stored at -80 °C, sperm morphology, viability, acrosome integrity, mitochondrial membrane potential and DNA fragmentation did not differ at successive evaluation times. Progressive motility was less (P < 0.05) after 12 h and total motility after 4 d of storage at -80 ºC as compared with that of the 0 h sample. With storage at the other temperatures (-21 and -8 ºC), there was a reduction of mean values for sperm total and progressive motility, viability and mitochondrial membrane potential after 12 h of storage at these temperatures. Results, therefore, indicate the use of ultra-freezers at -80 ºC to store frozen dog semen allows for maintenance of sperm characteristics for at least 15 d but motility is sustained for only 1 d. Neither of the -21 or -8 ºC storage temperatures were effective for storing of frozen dog sperm and retaining viability.

Cryo-milling using a spherical sugar: Contamination-free media milling technology

Milling beads experience wear upon repeated use. And milling beads made of material that is safe when ingested have not yet been developed. The present report describes the development and characteristics of spherical d-mannitol (SDM) beads, which would be safe when ingested. The model drug phenytoin was dispersed in liquid nitrogen along with SDM and the materials were agitated at high speed. The effects of the amount of beads, agitation speed, and milling time on phenytoin particle size, yield, and bead fractures were investigated using a central composite experimental design. The diameter of milled phenytoin particles decreased significantly as the amount of SDM beads and agitation speed increased. In contrast, no difference was found in the diameter with milling time. Although the fractured SDM ratio increased slightly at higher agitation speeds, the SDM was not broken and was durable enough for milling. This milling technique was applicable not only to phenytoin but also to other drug substances. Bead durability and applicability indicated that SDM can be used as wet milling beads that are considered safe for use if ingested.

Development of a rapid RNA extraction procedure from urediniospores of the leaf rust fungus, Puccinia triticina

Obtaining high quality RNA in good quantities is often a requirement for plant-pathogen interaction studies, so it becomes very essential that a highly efficient method should be deployed to isolate RNA from minute quantities of fungal spores. The methods available to date, either require a high quantity of spores or the use of expensive chemicals. The protocol discussed here for RNA isolation from Puccinia triticina pathotype 77-5 urediniospores utilizes TRI Reagent as extraction buffer that is widely used for RNA isolation from plant tissues. Urediniospores have a tough cell wall as compared to other plant cells. Therefore, the protocol was optimized keeping the primary focus on quickly disrupting cell walls. Two different methods, one using a combination of liquid nitrogen and ultrasonic water-bath and the other method using micro-homogenizer were utilized for crushing the spores in the present study. The developed methods do not utilize mortar and pestle, instead they promote direct crushing of urediniospores in tubes; thereby minimizing sample loss and enhancing quality.

Cryopreservation of Marchantia polymorpha spermatozoa

The liverwort Marchantia polymorpha has become one of the model organisms, since it has less genetic redundancy, sexual and asexual modes of reproduction and a range of genomic and molecular genetic resources. Cryopreservation of fertile spermatozoa eliminates time, space and labor for growing and maintaining male plants in reproductive phase, and also provides an optional way to backup lines. Here we report a protocol to cryopreserve spermatozoa of M. polymorpha in liquid nitrogen. A cryoprotective solution containing sucrose, glycerol and egg yolk and controlled cooling and warming processes led to successful recovery of motile M. polymorpha spermatozoa after the cryogenic process. The survival rate and average motility of spermatozoa after cryopreservation were maintained at 71 and 54% of those before cryopreservation, respectively. Cryopreserved spermatozoa were capable of fertilization to form normal spores. The technique presented here confers more versatility to experiments using M. polymorpha and could be applied to preservation of plant spermatozoa in general.

Assessment of the permeability properties of cryopreservation outer bags used in NHSBT

This study was carried out to investigate leakage/transport across the bag material of six outer cryopreservation bags in common use within NHS Blood and Transplant. In order to do this two different leak testing procedures; coloured dye and hydrogen tracer gas, were used. The data obtained show that a coloured dye cannot permeate through the materials both at room temperature and following storage at liquid nitrogen temperature (- 196 °C). In addition, when filled with the smallest elemental molecule, hydrogen, in the form of a tracer gas, all of the bags only allowed trace amounts of hydrogen to escape, either through the seal or the bag material. The data indicated that each of the bag materials tested would be capable of preventing bacterial or viral cross-contamination as long as the material remained intact.

A safety comparative study between freezing nitrogen ethanol composite and liquid nitrogen for cryotherapy of musculoskeletal tumors

Freezing nitrogen ethanol composite (FNEC) showed effective cryoablative ability for bone tumor ex vivo and in vivo comparable to liquid nitrogen (LN). We therefore wished to compare the radiant cooling damage of the surrounding tissue between FNEC and LN. The evaluation of the radiant cooling damage was demonstrated human bone xenograft transplantation (HXT) in a mouse model. Characterizations and quantifications of the damaging effects on morphologic features and apoptosis of the cryoablative surrounding bone tissue, muscle and epidermal layer of skin were compared. The radiant cooled damaging effects including epidermal rupture, hair follicle atrophy, dermis and subcutaneous crystal vacuolation of skin were significantly greater in LN than FNEC. Muscular apoptosis, structural shrinkage and bone cellular apoptosis were supposedly 15%-33% destroying degrees of LN more than FNEC. We concluded that FNEC is an innovative cryogenic material, and it could cause less cryoablative damage to surrounding normal tissue than LN. The findings might support the safety of FNEC being applied in clinical cryoablation therapy.

Successful joint preservation of distal radius osteosarcoma by en bloc tumor excision and reconstruction using a tumor bearing frozen autograft: a case report

Background

The wrist joint is an extremely rare site for osteosarcoma. Joint structure preservation to maintain good limb function is well described in case of knee osteosarcoma, whereas it is not described in case of wrist joint osteosarcoma. In this report, we present the first case of joint preservation surgery to treat distal radius osteosarcoma using a tumor bearing autograft treated with liquid nitrogen.

Case presentation

A 46-year-old male presented with swelling and pain in the right wrist and was diagnosed with conventional osteosarcoma of the distal radius. The patient responded well to neoadjuvant chemotherapy and the tumor shrank remarkably. Wide tumor excision to preserve the radiocarpal joint and reconstruction with a tumor bearing frozen autograft were performed. Partial bone union was detected 3 months postoperatively and complete bone union was detected 9 months postoperatively. Following the surgery, there was immediate commencement of the range of motion (ROM) training in both the wrist and fingers. At the final postoperative follow-up of 41 months, the patient had normal ROM in the wrist, fingers, and forearms, with a score of 100% in the Musculoskeletal Tumor Society (MSTS) score and was disease free.

Conclusion

We present the first case in which en bloc tumor excision with joint preservation of the wrist and reconstruction using a tumor bearing frozen autograft were performed. The surgery yielded excellent hand, wrist, and forearm function at the final follow-up.

Effect of cryopreservation on viability and growth efficiency of stromal-epithelial cells derived from neonatal human thymus

The thymus is the major site of T lymphocyte generation and so is critical for a functional adaptive immune system. Since, thymectomy is a component of neonatal surgery for congenital heart diseases, it provides great potential for collection and storage of thymic tissue for autologous transplantation. However, specific investigation into the optimum parameters for thymic tissue cryopreservation have not been conducted. In this research, we evaluated the effect of different cryoprotective media compositions, which included penetrating (Me₂SO, glycerol) and non-penetrating (dextran-40, sucrose, hydroxyethyl starch) components, on the viability and functionality of frozen-thawed human thymic samples to select an optimal cryoprotective medium suitable for long-term storage of thymic tissue and a stromal-epithelial enriched population. Our primary focus was on receiving, low-temperature storage, culturing and evaluation of thymic tissue samples from newborns and infants with congenital heart diseases, who had undergone thymectomy as a part of standard surgical procedure. Thus, this work builds the platform for autologous clinical intervention into the thymus-deficient patients with congenital heart diseases. From our data, we conclude that although there were no significant differences in efficiency of tested cryoprotective media compositions, the combination of Me₂SO and dextran-40 compounds was the most suitable for long-term storage both thymic cell suspensions and thymic fragments based on the viability of CD326⁺ epithelial cells and stromal-epithelial cell monolayer formation.

Retention in high-performance liquid chromatography at -196°C

Recently, we have developed ultralow-temperature high-performance liquid chromatography (HPLC) at -196°C using liquid nitrogen-based mobile phases. In this study, a retention model for ultralow-temperature HPLC, in which adsorption exchange and "pseudo partition" modes are combined, is proposed to describe the effect of the mobile phase composition on the retention of analytes. The experimental results agreed well with the equation of the proposed model. It was revealed that, in the low and high additive concentration regions, adsorption exchange and pseudo partition retention, respectively, dominate the analyte retention. The difference in the retention behavior between bare-silica and octadecylsilyl-modified silica (ODS) columns was also studied. Retention of alkanes in the ODS column was greater than that in the bare-silica one. Addition of both ethane and ethylene to the mobile phase in the ODS column afforded the elution of propylene, which was not eluted with the bare-silica column at -196°C.

Appendix E: Rapid-iTM: Closed Vitrification Device by Vitrolife

Cryopreservation of gametes and embryos is a growing technique in numerous reproductive fields including human-assisted reproduction. With improved understanding of embryo physiology and optimized culture conditions, there are now more embryos than ever to vitrify for potential use in subsequent cycles. Many gametes and embryos have been cryopreserved in open systems, but there are concerns with regard to contamination from the liquid nitrogen and also cross-contamination between patients' germplasm. The development of the Rapid-i™, a closed vitrification device that does not use direct contact with liquid nitrogen during vitrification or subsequent storage, will be discussed as well as clinical protocols for human oocytes and embryos.

Postoperative complications with cryotherapy in bone tumors

The technique of cryosurgery has been used to control local recurrence in a variety of benign and malignant bone tumors. Early studies revealed significant complication rates (25%) that included fracture, infection, and soft tissue injury. Our method of cryosurgery has yielded excellent tumor control with improved complication rates. The objective of this study is to determine the characteristics of postoperative complications after pouring liquid nitrogen into curettaged bone defects, and to review our current indications and surgical technique in bone tumor management.

We reviewed charts in over 200 patients who received cryoablation for bone tumors from 1994 to 2015. Imaging studies were evaluated in all patients diagnosed with a complication. All patients receiving cryotherapy had soft tissue management intraoperatively that included warm saline directed to the structures. Liquid nitrogen was poured into the bone defect and in some cases, additional spraying with a cryogun into the defect was performed.

The majority of cryotherapy was used in cases of active or aggressive benign tumors. Our low complication rate of 2.34% included 1 post-operative fracture, 3 infection, and 1 paraesthesia. Bone graft or cementation was used in the majority of patients, all of which fully incorporated.

Cryoablation is an excellent from of adjuvant therapy for active and aggressive benign tumors and may be used in malignant tumors as well. Soft tissue protection is critical to avoid skin necrosis and wound breakdown. We recommend the use of cryotherapy in active and aggressive bone tumors as an adjuvant treatment prior to bone grafting or cementation.

•

Cryoablation as an adjuvant treatment is recommended in active and aggressive benign tumors.

•

A combination of a slow freeze and quick thaw, repeated for two cycles giving optimal penetration and stability across structures.

•

Soft tissue management with warm saline is critical in preventing intraoperative injury.

•

Controlled cryotherapy techniques can limit complication rates and local recurrence rates.

Changes in transcript expression patterns as a result of cryoprotectant treatment and liquid nitrogen exposure in Arabidopsis shoot tips

Transcripts related to abiotic stress, oxidation, and wounding were differentially expressed in Arabidopsis shoot tips in response to cryoprotectant and liquid nitrogen treatment. Cryopreservation methods have been implemented in genebanks as a strategy to back-up plant genetic resource collections that are vegetatively propagated. Cryopreservation is frequently performed using vitrification methods, whereby shoot tips are treated with cryoprotectant solutions, such as Plant Vitrification Solution 2 (PVS2) or Plant Vitrification Solution 3 (PVS3); these solutions remove and/or replace freezable water within the meristem cells. We used the model system Arabidopsis thaliana to identify suites of transcripts that are up- or downregulated in response to PVS2 and PVS3 treatment and liquid nitrogen (LN) exposure. Our results suggest that there are many changes in transcript expression in shoot tips as a result of cryoprotection and that these changes exceed the number detected as a result of LN exposure. In total, 180 transcripts showed significant changes in expression level unique to treatment with either the cryoprotectant or cryopreservation followed by recovery. Of these 180 transcripts, 67 were related to stress, defense, wounding, lipid, carbohydrate, abscisic acid, oxidation, temperature (cold/heat), or osmoregulation. The responses of five transcripts were confirmed using qPCR methods. The transcripts responding to PVS2 + LN suggest an oxidative response to this treatment, whereas the PVS3 + LN treatment invoked a more general metabolic response. This work shows that the choice of cryoprotectant can have a major influence on the patterns of transcript expression, presumably due to the level and extent of stress experienced by the shoot tip. As a result, there may be divergent responses of study systems to PVS2 and PVS3 treatments.

Tissue Fixation and Processing for the Histological Identification of Lipids

Lipids are a heterogeneous group of substances characterized by their solubility in organic solvents and insolubility in water. Lipids can be found as normal components of different tissues and organs, and they can be affected by several pathological conditions. The histochemical identification of lipids plays an important role in histopathological diagnosis and research, but successful staining depends on adequate fixation and processing of the tissue. Here we describe methods to fix and process tissue samples for the histochemical identification of lipids in frozen or paraffin-embedded tissues.

Does Parmelina tiliacea lichen photosystem II survive at liquid nitrogen temperatures?

Parmelina tiliacea lichens kept in the wet and dry state were stored in liquid nitrogen for 1 week and the subsequent recovery of their photosynthetic apparatus was followed. The chlorophyll a fluorescence rise and the maximum quantum yield of primary photochemistry φ_Po (F_V/F_M) were analysed for this purpose. Storage of wet thalli for 1 week in liquid nitrogen led to an impairment of photosystem II and probably the photosynthetic apparatus as a whole, from which the thalli did not recover over time. Thalli exposed in the dry state thalli were far less affected by the treatment and recovered well. These results indicate that the thalli are extremely tolerant to liquid nitrogen temperatures only in the dry state.

The cryoablation of lung tissue using liquid nitrogen in gel and in the ex vivo pig lung

PURPOSES

To examine the efficiency of cryoablation using liquid nitrogen in lung tissue, we measured the size and temperature distribution of the frozen area (iceball) in gel and in the ex vivo pig lungs.

METHODS

Cryoprobes with diameters of 2.4 and 3.4 mm (2.4D and 3.4D, respectively) were used. Three temperature sensors were positioned at the surface of the cryoprobe and at distances of 0.5 and 1.5 cm from the cryoprobe. The ex vivo pig lungs were perfused with 37 °C saline and inflated using ventilator to simulate in vivo lung conditions.

RESULTS

In gel, the 2.4D and 3.4D probes made iceballs of 3.9 ± 0.1 and 4.8 ± 0.3 cm in diameter, respectively, and the temperature at 1.5 cm from those probes reached -32 ± 8 and -53 ± 5 °C, respectively. In the pig lung, the 2.4D and 3.4D probes made iceballs of 5.2 ± 0.1 and 5.5 ± 0.4 cm in diameter, respectively, and the temperature at 1.5 cm from these probes reached -49 ± 5 and -58 ± 3 °C, respectively.

CONCLUSION

Liquid nitrogen cryoablation using both 2.4D and 3.4D probes made iceballs that were of sufficient size, and effective temperatures were reached in both gel and the ex vivo pig lung.

Cryopreservation of Gemmae from the Liverwort Marchantia polymorpha L

The liverwort Marchantia polymorpha L. is one of the key model plants in evo-devo studies, and an increasing number of transgenic and mutant lines have been established. For reliable long-term preservation of M. polymorpha plants, spores have been used, but crossing is indispensable to obtain them. Gemmae, however, are vegetative clones and readily available in large numbers without crossing, thereby enabling the clonal preservation and rapid propagation of transgenic or mutant lines. Here, we report a simple cryopreservation protocol for in vitro grown M. polymorpha gemmae using aluminum cryoplates. Gemmae were pre-cultured on sucrose-containing medium, embedded in calcium alginate gel on the surface of a cryoplate, moderately dehydrated and stored in liquid nitrogen. After rapid thawing, the stored gemmae showed a 100% survival rate. Our protocol does not require plant growth regulators such as ABA, and takes only 1 h to complete except for 1 d of pre-culture. Furthermore, gemmae treated as described above but then air-dried for 2 h can be stored at -80°C for at least 1 year without a significant decrease in survival rate, which is convenient for most laboratories that have a -80°C freezer but not a liquid nitrogen container for long-term storage. These preservation techniques for M. polymorpha should increase their availability in the research community.

Implantation of Liquid Nitrogen Frozen Tumor Tissue after Posterior Decompression and Stabilization for Metastatic Spinal Tumors

Study Design

A retrospective study.

Purpose

To evaluate the immunity-enhancing effect of implantation of a liquid nitrogen-treated tumor.

Overview of Literature

We have developed a new technique of implanting a tumor frozen in liquid nitrogen after posterior decompression and stabilization, with the aim of enhancing antitumor immunity in order to prolong the survival period of the patient. In the current study, the immunity-enhancing effect of this new technique has been evaluated.

Methods

The subjects were 19 patients in whom we had earlier performed decompression and stabilization between April 2011 and September 2013. The 19 subjects were divided into two groups, namely a frozen autologous tumor tissue implantation group (n=15; "implantation group"), which consisted of patients, who underwent implantation with autologous tumor tissue frozen in liquid nitrogen, and a control group (n=4), which consisted of patients, who did not undergo autologous cancer transplantation. To evaluate the immunity-enhancing effect of the protocol, plasma cytokines (interferon [IFN]-γ and interleukin [IL]-12) were analyzed before surgery and a month after surgery.

Results

The mean rate of increase in IFN-γ was significantly higher in the implantation group (p=0.03). Regarding IL-12, no significant difference was observed between the groups, although the implantation group exhibited increased levels of IL-12 (p=0.22).

Conclusions

Decompression and stabilization combined with autologous frozen tumor cell implantation can enhance cancer immunity in metastatic spinal tumor patients. It is hypothesized that this procedure might prevent local recurrence and prolong survival period.

Small-scale experimental study of vaporization flux of liquid nitrogen released on water

A small-scale experimental study was conducted using liquid nitrogen to investigate the convective heat transfer behavior of cryogenic liquids released on water. The experiment was performed by spilling five different amounts of liquid nitrogen at different release rates and initial water temperatures. The vaporization mass fluxes of liquid nitrogen were determined directly from the mass loss measured during the experiment. A variation of initial vaporization fluxes and a subsequent shift in heat transfer mechanism were observed with changes in initial water temperature. The initial vaporization fluxes were directly dependent on the liquid nitrogen spill rate. The heat flux from water to liquid nitrogen determined from experimental data was validated with two theoretical correlations for convective boiling. It was also observed from validation with correlations that liquid nitrogen was found to be predominantly in the film boiling regime. The substantial results provide a suitable procedure for predicting the heat flux from water to cryogenic liquids that is required for source term modeling.

Long term storage of Pleurotus ostreatus and Trametes versicolor isolates using different cryopreservation techniques and its impact on laccase activity

The strain Pleurotus ostreatus Florida f6, its 45 basidiospore-derived isolates (both monokaryons and dikaryons prepared in our laboratory), Trametes versicolor strain CCBAS 614 and 22 other T. versicolor isolates obtained from the sporocarps collected in distant localities were successfully preserved for 12 y using perlite and straw cryopreservation protocols. All tested isolates survived a 12-year storage in liquid nitrogen (LN) and their laccase production and Poly B411 decolorization capacity was preserved. Also mycelium extension rate and the types of colony appearance of individual isolates remained unchanged. Different cryopreservation techniques were also tested for the short time (24 h) and the long time (6 m) storage of the culture liquid with extracellular laccase produced by T. versicolor strain CCBAS 614. The results showed that 10 % glycerol was the most suitable cryopreservant. The absence of the cryopreservant did not cause high loss of laccase activity in the samples; the presence of DMSO (5 or 10 %) in LN-stored samples caused mostly a decrease of laccase activity. For the preservation of laccase activity in the liquid culture the storage in the freezer at -80 °C is more convenient than the storage in liquid nitrogen.

En Bloc Resection and Reconstruction Using a Frozen Tumor-Bearing Bone for Metastases of the Spine and Cranium from Retroperitoneal Paraganglioma

BACKGROUND

Paragangliomas are neuroendocrine tumors that originate from autonomic nervous system-associated paraganglia and are rare tumors accounting for only 0.3% of all neoplasms. Malignant paragangliomas frequently spread to the skeleton. The authors present a case of malignant paraganglioma with bone metastases to the spine and cranium, as well as excellent local control achieved with en bloc tumor resection and reconstruction using frozen tumor-bearing bone for the sites of the metastases.

CASE

The patient was a 61-year-old woman who underwent retroperitoneal paraganglioma resection 12 years previously. Nine years after the primary surgery, she began to experience back pain. Magnetic resonance imaging revealed an isolated metastasis in T6, and the following evaluation detected another metastasis in the left temporal bone. We performed curative surgeries for the metastases, including total en bloc spondylectomy of T6, partial craniectomy for the cranial metastasis, and spinal and cranial reconstruction using frozen tumor-bearing bone for the sites of the metastases. At the 24-month follow-up examination, bone fusion was achieved between the frozen bone and the adjacent healthy bone in the spine and cranium. At 36 months postoperatively, an asymptomatic metastatic lesion was found in the pelvis. Nevertheless, no local recurrences at the surgical sites were detected. Her quality of life and performance in activities of daily living were well preserved. To the author's knowledge, this is the first report to present a case of cranioplasty achieved using a liquid nitrogen frozen, tumor-bearing autologous bone flap in a single-stage operation.

Determination of heat transfer coefficients in plastic French straws plunged in liquid nitrogen

The knowledge of the thermodynamic process during the cooling of reproductive biological systems is important to assess and optimize the cryopreservation procedures. The time-temperature curve of a sample immersed in liquid nitrogen enables the calculation of cooling rates and helps to determine whether it is vitrified or undergoes phase change transition. When dealing with cryogenic liquids, the temperature difference between the solid and the sample is high enough to cause boiling of the liquid, and the sample can undergo different regimes such as film and/or nucleate pool boiling. In the present work, the surface heat transfer coefficients (h) for plastic French straws plunged in liquid nitrogen were determined using the measurement of time-temperature curves. When straws filled with ice were used the cooling curve showed an abrupt slope change which was attributed to the transition of film into nucleate pool boiling regime. The h value that fitted each stage of the cooling process was calculated using a numerical finite element program that solves the heat transfer partial differential equation under transient conditions. In the cooling process corresponding to film boiling regime, the h that best fitted experimental results was h=148.12±5.4 W/m(2) K and for nucleate-boiling h=1355±51 W/m(2) K. These values were further validated by predicting the time-temperature curve for French straws filled with a biological fluid system (bovine semen-extender) which undergoes freezing. Good agreement was obtained between the experimental and predicted temperature profiles, further confirming the accuracy of the h values previously determined for the ice-filled straw. These coefficients were corroborated using literature correlations. The determination of the boiling regimes that govern the cooling process when plunging straws in liquid nitrogen constitutes an important issue when trying to optimize cryopreservation procedures. Furthermore, this information can lead to improvements in the design of cooling devices in the cryobiology field.

Influences of the sample shape and compression temperature on the deformation behavior and mechanical properties of human dentin

Deformation behavior and mechanical properties of samples of human dentin having different geometries were studied under compression in liquid nitrogen. In this case, the plastic response of the collagen fibers in dentin was excluded. The findings were compared with the mechanical properties of dentin at room temperature. Such a comparison allows the plastic contribution of collagen in human dentin to be estimated for samples of different shapes. It was shown that the deformation behavior of human dentin under compression is similar at 77K and 300 K. The dentin samples with low aspect ratio exhibited almost brittle behavior, whereas those with high aspect ratio were prone to considerable deformation. SEM study of the fracture surfaces of samples tested at room and liquid nitrogen temperatures has shown that they are similar. Examination of cracks on the compression surface of samples agrees with this conclusion. However, the mechanical characteristics of dentin depended on the temperature of testing. The compression strength and elastic deformation of dentin at 77K are higher than these parameters at room temperature, while the plasticity of dentin at 77K is lower. The plastic contribution of collagen fibers at room temperature was estimated on the basis of this comparison. The total plasticity of dentin is the sum of the contributions of both collagen and the geometry of the sample. The plasticity of dentin samples having a low aspect ratio is provided by collagen fibers only, while geometric factors are dominant for samples with a high aspect ratio. The contribution of collagen fibers to the plasticity of dentin depends on the geometry of samples with an intermediate aspect ratio.