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Loss of plasma membrane proteins of bull spermatozoa through the freezing-thawing process.

The widespread application of A. I. and realization of its full potential depends largely on the use of frozen semen. However, fertility resulting from A. I. is poorer than that from fresh semen in most species. The objective of this study was to compare the protein composition of fresh and frozen-thawed bull sperm plasma membrane surface. The effect of Tween 20 on protein removal from fresh and frozen sperm plasma membrane surface was studied and compared. The effect of incubation with different detergent concentrations on sperm motility and viability was examined. Approximately 2 x 10(8) frozen-thawed bull spermatozoa washed through a discontinuous Percoll gradient were incubated for 15 min at 20 degrees C with 0.01, 0.03 and 0.05% Tween 20. Sperm motility was completely eliminated at all 3 assayed detergent concentrations, while the initial sperm viability of 52% was decreased to 26, 10 and 5%, respectively, at the 3 concentrations. The removal of sperm plasma membrane proteins also increased from 0.72 mg to 2 mg with 0.05% Tween 20. Similar results were found with fresh semen samples. Although the amount of extracted proteins was significantly lower than that obtained with frozen spermatozoa, fresh sperm motility was likewise eliminated by the detergent treatment, and sperm viability was decreased. A semen sample with an initial sperm viability of 59% had a value of only 8% after treatment with 0.05% Tween 20. Comparative SDS-PAGE analysis of the extracted fractions from fresh and frozen-thawed semen treated with Tween 20 showed that the higher amount of extracted proteins in the frozen semen samples corresponded to the egg yolk lipoproteins in the cryoprotectant medium. However, it is worth noting that 4 more bands were found in the sample obtained from fresh semen than from frozen semen. These results indicate that some cell membrane proteins are lost through the freezing-thawing process.

Animals↗

An efficient and reproducible method for measuring hydrogen peroxide in exhaled breath condensate.

We investigated the sensitivity and reproducibility of a test procedure for measuring hydrogen peroxide (H202) in exhaled breath condensate and the effect of storage of the condensate on the H2O2 concentration, and compared the results to previous studies. Twenty stable COPD patients breathed into our collecting device twice for a period of 10 min. The total exhaled air volume (EAV) and condensate volume were measured both times and the H2O2 concentration of the condensate was determined fluorimetrically. The concentration was measured again after freezing the reaction product at -70 degrees C for a period of 10, 20 and 40 days. We collected 2-5 ml condensate in 10 min. The EAV and condensate volumes were strongly correlated. There was no significant difference between the mean H2O2 concentration of the first and second test. We obtained a detect on limit for the H2O2 concentration of 0.02 micromoll(-1). The H2O2 concentration appeared to remain stable for a period up to 40 days of freezing. Compared to previous studies we developed a more efficient breath condensate collecting device and obtained a lower H2O2 detection limit. The measurement of exhaled H2O2 was reproducible. In addition, storage of the samples up to 40 days showed no changes in H2O2 concentration.

Aged↗

Artificial inseminations with frozen semen and application of DNA fingerprint for parents/offspring conformation on Great Pyrenees.

Frozen semen of Great Pyrenees, air-shipped from France, was artificially inseminated (AI) to two Great Pyrenees bitches. Blood LH and P concentrations and vulval width principally determined optimal breeding time of bitches. AI were performed on 17 to 21 days from the onset of estrous bleeding, and 25 days after final Al, pregnancy of one bitch, with two fetuses, was identified by ultrasound image diagnostic equipment. On 62 days, the bitch whelped one male pup and one female pup. Blood samples were obtained from four parents and offspring, and their DNA was extracted. DNA samples digested with four kinds of restriction endonucleases, and resulting fragmented DNA were used as test samples for DNA fingerprinting with Myo prove. As a result bands from pups, displayed by any enzyme, were inherited from either parent, and clear parent-offspring relationships were identified.

Animals↗

Immunohistochemical localization of ganglioside GD3 in human malignant melanoma, epithelial tumors, and normal tissues.

The specific tissue distribution of melanoma-associated ganglioside II3-alpha-N-acetylneuraminosyl-alpha 2----8-N-acetylneuraminosyllactosylceramide (GD3) was studied on 175 cryopreserved, unfixed human tissue sections with R-24 mouse monoclonal antibody by indirect immunoperoxidase staining. A striking specificity of monoclonal antibody R-24 for malignant melanoma tissues was established. Ganglioside GD3 was detected in all 21 tissue sections of 21 patients with primary melanoma and in all 37 probes of 24 patients with metastatic malignant melanoma. The majority of tumor cells in the samples of primary malignant melanoma expressed GD3; however, GD3 expression was more heterogeneous in samples of metastatic lesions even in different metastases of the same patient. Of 11 nevi, 9 reacted with monoclonal antibody R-24, while melanocytes in the basal layer of normal skin stained only weakly and irregularly. None of the 32 normal and 12 fetal human tissue types were R-24 positive, but a strong cytoplasmic staining was observed with single cells in the dermis and in the interstitial tissue of the gastrointestinal tract, in the interlobular septa of the thymus, and in other distinct locations. Only two malignant carcinoid tumors of 38 nonmelanomatous tumors tested reacted with monoclonal antibody R-24.

Adult↗

Analysis of techniques to obtain plasma for measurement of levels of free fatty acids.

Accuracy in measurement of plasma free fatty acids (FFA), and therefore prevention of the in vitro lipolysis, is a crucial step to understand the physiologic role of plasma FFA and their relationships in the pathogenesis of important metabolic disorders such as central obesity, insulin resistance, and diabetes mellitus. As lipoprotein triglyceride-fatty acids are elevated in these states, in vitro lipolysis of triglycerides may artifactually increase FFA. Plasma FFA were measured in subjects before and after heparin administration, under different experimental conditions affecting the in vitro activity of lipoprotein lipase (LPL) and hepatic lipase (HL). Paraoxon, a cholinesterase inhibitor neurotoxin known to block plasma lipolytic activity, and preextraction timing and temperature of collection were tested. Paraoxon was required to prevent triglyceride hydrolysis in: a) preheparin plasma allowed to stand at room temperature (21 degrees C) for 2 h, before being frozen at -20 degrees C (FFA = 1817 +/- 291 vs. 698 +/- 66 microEq/l, P < 0.005, mean +/- SEM, without and with paraoxon, respectively); and b) in postheparin plasma immediately stored at -20 degrees C (FFA = 2682 +/- 357 vs. 1299 +/- 150 microEq/l, P < 0.005, without and with paraoxon, respectively). No difference in the FFA level was found in preheparin plasma collected either with or without paraoxon when: a) the samples were placed in ice and immediately assayed; b) the specimens were immediately frozen at -70 degrees C and assayed 60 days later.(ABSTRACT TRUNCATED AT 250 WORDS)

Artifacts↗

Numerical investigations of transient heat transfer characteristics and vitrification tendencies in ultra-fast cell cooling processes.

During freezing, cells are often damaged directly or indirectly by ice formation. Vitrification is an alternative approach to cryopreservation that avoids ice formation. The common method to achieve vitrification is to use relatively high concentrations of cryoprotectant agents (CPA) in combination with a relatively slow cooling rate. However, high concentrations of CPAs have potentially damaging toxic and/or osmotic effects on cells. Therefore, establishing methods to achieve vitrification with lower concentrations of CPAs through ultra-fast cooling rates would be advantageous in these aspects. These ultra-fast cooling rates can be realized by a cooling system with an ultra-high heat transfer coefficient (h) between the sample and coolant. The oscillating motion heat pipe (OHP), a novel cooling device utilizing the pressure change to excite the oscillation motion of the liquid plugs and vapor bubbles, can significantly increase h and may fulfill this aim. The current investigation was designed to numerically study the effects of different values of h on the transient heat transfer characteristics and vitrification tendencies of the cell suspension during the cooling processes in an ultra-thin straw (100 microm in diameter). The transient temperature distribution, the cooling rate and the volume ratio (x) of the ice quantity to the maximum crystallizable ice of the suspension were calculated. From these numerical results, it is concluded that the ultra-high h (>10(4) W/m2 K) obtained by OHPs could facilitate vitrification by efficiently decreasing x as well as the time to pass through the dangerous temperature region where the maximum ice formation happens. For comparison, OHPs can decrease both of the parameters to less than 20% of those from the widely used open pulled straw methods. Therefore, the OHP method will be a promising approach to improving vitrification tendencies of CPA solutions and could also decrease the required concentration of CPAs for vitrification, both of which are of great importance for the successful cryopreservation of cells by vitrification.

Cryopreservation↗

Cryopreservation of human platelets with dimethyl sulfoxide: changes in biochemistry and cell function.

BACKGROUND: The shelf life of liquid-stored platelet concentrates is limited to 5 days. Therefore, much work has been carried out in an attempt to establish the optimum method for cryopreservation. Among the various cryoprotectants, dimethyl sulfoxide (DMSO) has been shown to be the most effective. However, DMSO-frozen platelets are characterized by a number of cell lesions. This report describes metabolic and functional changes that should give rise to some concern about the functional integrity of these cells. STUDY DESIGN AND METHODS: Single-donor platelet concentrates were frozen in liquid nitrogen by use of DMSO (5%). After thawing, the cells were washed and resuspended in autologous plasma. Before, during, and after the freezing process, samples for analysis of metabolic measures (e.g., pH; calcium, potassium, and lactate dehydrogenase concentrations; plasma complement factors) and functional measures (e.g., aggregometry, in vitro bleeding time, alpha-granule membrane protein-140 expression) were taken. RESULTS: Mean platelet volume increases during the deep-freezing process. Potassium, calcium, and lactate dehydrogenase are released from the intracellular space to the extracellular space. A strong activation of complement, which is mainly due to the addition of DMSO, is observed. Platelets become activated as indicated by the expression of alpha-granule membrane protein-140. Accordingly, decreased platelet function can be observed. CONCLUSION: DMSO-frozen platelets are characterized by several metabolic and functional changes. Although these cells have been shown to exert hemostatic effects in vivo, it is conceivable that those effects could be improved by further development of platelet-freezing techniques.

Blood Platelets↗

Inhibition of bacterial ice nucleation by polyglycerol polymers.

The simple linear polymer polyglycerol (PGL) was found to apparently bind and inhibit the ice nucleating activity of proteins from the ice nucleating bacterium Pseudomonas syringae. PGL of molecular mass 750 Da was added to a solution consisting of 1 ppm freeze-dried P. syringae 31A in water. Differential ice nucleator spectra were determined by measuring the distribution of freezing temperatures in a population of 98 drops of 1 microL volume. The mean freezing temperature was lowered from -6.8 degrees C (control) to -8.0,-9.4,-12.5, and -13.4 degrees C for 0.001, 0.01, 0.1, and 1% w/w PGL concentrations, respectively (SE < 0.2 degrees C). PGL was found to be an ineffective inhibitor of seven defined organic ice nucleating agents, whereas the general ice nucleation inhibitor polyvinyl alcohol (PVA) was found to be effective against five of the seven. The activity of PGL therefore seems to be specific against bacterial ice nucleating protein. PGL alone was an ineffective inhibitor of ice nucleation in small volumes of environmental or laboratory water samples, suggesting that the numerical majority of ice nucleating contaminants in nature may be of nonbacterial origin. However, PGL was more effective than PVA at suppressing initial ice nucleation events in large volumes, suggesting a ubiquitous sparse background of bacterial ice nucleating proteins with high nucleation efficiency. The combination of PGL and PVA was particularly effective for reducing ice formation in solutions used for cryopreservation by vitrification.

Bacterial Outer Membrane Proteins↗

Current and future concepts and practices in human sperm cryobanking.

This article focuses on a range of issues that are of current concern to those working in human sperm cryobanking and considers them within a general framework of risk analysis and management, taking into account the available evidence and perceptions of 'best practice' from both the medical and legal perspectives. In particular, issues arising from concerns over the risk of cross-contamination between samples during storage immersed in liquid nitrogen have been analysed in detail. Even though such an occurrence has never been reported for spermatozoa or embryos, and the risk is generally accepted to be vanishingly small, it does represent a finite risk and all reasonable measures should be taken to reduce the chance of its occurring. It is concluded that all methods used to collect, cryopreserve, store, thaw and use cryobanked human spermatozoa must address the risk of contamination from any source throughout the entire process. To assist workers in this area, a series of recommendations as to current best practice are made, based upon conclusions from risk analyses using currently available information.

Cryopreservation↗

Trehalose-enhanced fluidity of the goat sperm membrane and its protection during freezing.

In an attempt to find a suitable freezing method for goat semen, two experiments were conducted to study the influence of trehalose on the cryopreservation of goat spermatozoa. In experiment 1, goat spermatozoa were frozen in trehalose extender (0.375 M) alone (100%) or at different combinations of trehalose with Tris-citric acid-glucose (TCG) extender (0%, 25%, 50%, 75%). Final concentrations of 20% (v:v) egg yolk and 4% (v:v) glycerol were employed in the extenders (osmolality = 370, pH = 7). Sperm motility was assessed using a computer-assisted sperm analysis system and acrosome integrity was assessed using fluorescein isothiocyanate-labeled peanut agglutinin (FITC-PNA). The sperm-motility parameters improved significantly by increasing the concentration of trehalose (P < 0.05) and significantly high recovery rates for the motility parameters were also achieved by a high concentration of trehalose (P < 0.05). Motility of the frozen-thawed spermatozoa after a 3-h incubation improved significantly with increasing concentrations of trehalose in the extender (P < 0.05). The 75% and 100% trehalose extenders yielded a significant increase in the percentage of spermatozoa with intact acrosome (P < 0.05). In experiment 2, merocyanine 540/Yo-Pro staining was used to study the influence of trehalose on membrane fluidity compared with that of sucrose and TCG. Percentage of cells with high merocyanine fluorescence was significantly higher in spermatozoa treated with trehalose than sucrose or TCG (P < 0.05), indicating a significantly highest membrane fluidity of sperm samples extended with trehalose solution. We thus conclude that the substitution of a Tris-citric acid diluent composition with trehalose significantly improves the freezability of goat spermatozoa. Furthermore, the cryoprotective effects of trehalose observed in this study may be due to enhanced sperm membrane fluidity before freezing.

Acrosome Reaction↗

Storage of Chinchilla lanigera semen at 4 degrees C for 24 or 72 h with two different cryoprotectants.

The objectives of this study were to: (a) test the functional activity of Chinchilla lanigera spermatozoa suspended in either glycerol or ethylene glycol, cooled to 4 degrees C, and stored for 24 or 72 h and (b) investigate, after these cooling periods, the effects of incubating sperm at 37 degrees C (for 4 h) upon sperm functional activity. The ejaculate was mixed with the cryoprotectant medium (at 1 M final concentration) and cooled to 4 degrees C. After warming, sperm motility, sperm viability, hypoosmotic swelling test results, and acrosomal integrity were significantly higher for samples containing ethylene glycol than for those in glycerol, stored for 24 or 72 h, and then assayed after 0 or 4 h incubation at 37 degrees C. A significant reduction of sperm motility and viability was detected only when the glycerol cryoprotectant agent was employed, compared to the fresh samples. These results clearly indicate that under our experimental conditions, ethylene glycol is a better protectant for sperm storage than glycerol.

Animals↗

Re-evaluation of the storage conditions for blood samples which are used for determination of complement activation.

EDTA-blood samples derived either from healthy staff or septic patients were investigated for in vitro complement activation during the first 48 h after blood drawing at 4 degrees C and 20 degrees C. For this purpose C3a/C3a desArg plasma levels were determined by the ABICAP C3a assay. Within the septic group no complement activation was detectable during the whole observation period. However, if blood from healthy persons was stored for longer than 6 h at 20 degrees C complement activation occurred. The most profound activation was found in EDTA-blood stored for 48 h at 20 degrees C. C3a values in this sample increased four-fold from 56 +/- 7 ng/ml to 222 +/- 38 ng/ml. From these data we conclude that both immediate cooling of EDTA-blood to 4 degrees C, as well as the immediate separation of plasma as proposed by Mollnes et al. (Clin. Exp. Immunol. (1988) 73, 484), is not necessary for determination of anaphylatoxin plasma values. Storage of EDTA-blood samples for up to 6 h without the need to perform centrifugation should allow anaphylatoxin measurement to become a routine parameter for diagnosis of inflammatory diseases.

Anaphylatoxins↗

Influence of pre-analytical and analytical factors on soluble CD40L measurements.

The soluble form of CD40L (CD40 ligand), a pro-atherogenic mediator, has emerged as a diagnostic and prognostic marker for cardiovascular events. However, as platelets can shed CD40L upon activation, accurate measurement has proved challenging. The present study addresses the controversy regarding the appropriate specimen and preparation for laboratory evaluation of blood sCD40L (soluble CD40L). Serum and plasma (collected in EDTA, citrate or heparin) were collected from healthy volunteers (n=20), and sCD40L was analysed by ELISA immediately or after one to three freeze-thaw cycles and at different centrifugation speeds. Urine sCD40L levels were measured in subjects with low- and high-plasma sCD40L levels. Serum sCD40L levels (5.45+/-4.55 ng/ml; P<0.001) were higher than in citrate, EDTA or heparin plasma (1.03+/-1.07, 1.43+/-1.03 or 1.80+/-1.25 ng/ml respectively), with no significant differences between plasma preparations. Increasing g values (200-13000 g), which gradually deplete plasma of platelets, yielded lower sCD40L levels. Repeated freeze-thaw cycles significantly (P<0.05) increased sCD40L concentrations in platelet-rich, but not platelet-depleted, plasma (up to 2.4-fold). Bilirubin and haemoglobin interfered positively, and triacylglycerols (triglycerides) and cholesterol quenched CD40L signalling. No sCD40L was detected in urine samples. In conclusion, serum yields higher sCD40L concentrations than plasma; accurate measurements of sCD40L require exclusion of platelets and avoiding their post-hoc activation. Samples with high concentrations of bilirubin, haemoglobin and/or triacylglycerols should be excluded, as these substances interfere with the assay.

Adult↗

Rapid electromagnetic warming of cells and tissues.

We describe a system for thawing frozen cell suspensions and tissues by electromagnetic absorption. A 25-ml sample is heated in a cylindrical resonant cavity, which is excited in three modes all close to 434 MHz. Maximum warming rates are over 10 degrees C/s (600 C/min), and a frozen sample may be brought from -65 degrees C to room temperature in < 30 s, with final spatial differences of < 20 degrees C. Samples may be frozen externally, or cooled within the cavity at typically 1 degree C/min. We have also used the resonant cavity to measure the permittivity and conductivity of the sample at temperatures from -83 degrees C to +8 degrees C. By measuring the heat capacity of the sample, we have calculated the power deposited in it as a function of its temperature. The system is currently being used to investigate the effect of warming rate on cell survival.

Animals↗

[The increasing importance of tumor and tissue banks in the light of genomic and proteomic research].

Recent technological advances in genome and proteome research offer new perspectives for diagnosis and therapy. The DNA chip technology as well as high-resolution two-dimensional gel electrophoresis in combination with mass spectrometry is able to provide comprehensive information on gene and protein expression patterns, which allow insights into the dynamic and functional aspects of diseases. The application of these techniques depends on the availability of unfixed fresh or cryopreserved tissue with short ischaemia time. For this reason tissue banks are of increasing importance. The pathologist with his expertise and responsibility for histopathological diagnosis, plays a central role in the collection of the human tissues, in accordance with medical, legal and ethical standards, not only for diagnostic purposes, but also for research. The scientific value of a tissue bank is markedly increased if tissue samples are accompanied by detailed patient data as well as blood samples. Informed consent given by the patient is an essential requirement for the use of human tissue banks in biomedical research. The informed consent should not be restricted to scientific investigations but also include the potential commercial use of the data generated.

Animals↗

Microglia-passaged simian immunodeficiency virus induces neurophysiological abnormalities in monkeys.

Four rhesus macaques were inoculated intravenously with a cryopreserved stock of microglia obtained from a simian immunodeficiency virus (SIV)-infected rhesus macaque. Before infection, three of the four monkeys were trained and tested daily on a computerized neuropsychological test battery. After SIV infection, behavioral testing continued to monitor deficits associated with disease progression. Five additional age-matched, behaviorally trained monkeys served as controls. Neurophysiological testing for visual and auditory evoked responses was accomplished 37-52 weeks after infection in all monkeys. Subsequently, all four SIV-infected monkeys and one control subject were sacrificed, and samples of brain tissue were taken for pathological analysis. SIV-infected monkeys demonstrated abnormal responses in both auditory and visual evoked responses. In addition, around the time of electrophysiological recording, all three SIV-infected, behaviorally trained monkeys exhibited significant decreases in progressive-ratio performance, reflecting a reduction in reinforcer efficacy. One subject also demonstrated impairments in shifting of attentional set and motor ability at that time. Neuropathological evaluation revealed that all four SIV-infected monkeys exhibited numerous perivascular and parenchymal infiltrating T cells. These findings document that SIV causes electrophysiological, behavioral, and neuropathological sequelae similar to what has been observed in the human neuroAIDS syndrome. Our observations further validate the simian model for the investigation of the pathogenesis of AIDS dementia and for the investigation of drugs with potential therapeutic benefits.

AIDS Dementia Complex↗

Experimental microbial contamination and disinfection of dry (vapour) shipper dewars designed for short-term storage and transportation of cryopreserved germplasm and other biological specimens.

Cryopreservation, storage and transport of cryopreserved germplasm without the risk of disease transmission is of great concern to animal and human health authorities. Here we report on the efficacy of microbial decontamination of the liquid nitrogen (LN) dry (vapour) shippers used for short-term storage and transportation of germplasm and other biological specimens. Dry shippers containing either a hydrophobic or a non-hydrophobic LN absorbent were experimentally contaminated with high titers of cultures of Pseudomonas aeruginosa, Escherichia coli, Staphylococus aureus, bovine viral diarrhea virus (BVDV) and bovine herpesvirus-1 (BHV-1). Biocidals with broad spectrum antimicrobial activity and gas vapours of formalin and ethylene oxide were used for disinfection of the dewars. Among the biocidals used, treatment with sodium hypochlorite solution, the quaternary ammonium-based disinfectants and peracetic acid were the most effective and useful for dry shippers with a hydrophobic LN absorbent. None of the bacterial or viral microorganisms were detected in samples of semen and embryos stored in dry shippers following their disinfection with these biocides. An application of some other disinfectants, due to their foaming properties or to the permeability of the absorbent hydrophobic membrane (HM) was not effective or may have caused irreversible damage to the LN absorbent. Gas sterilization by ethylene oxide in contrast to formalin was fully effective for both types of dry shippers.

Animals↗

Integrating Biobanking Into Conservation Practice: The Development and Impact of the EAZA Biobank.

Zoological biobanks are becoming essential tools in conservation, offering a means to preserve genetic material and support in situ population management amid accelerating biodiversity loss. With rapid advances in genomics, cryopreservation, and assisted reproduction technologies, biobanks enable a proactive approach to providing insurance against genetic erosion and facilitating future research, supplementation, and genetic rescue. However, to be effective, zoological biobanks must be purposefully designed, strategically integrated into conservation frameworks such as the Convention on Biological Diversity (CBD) Kunming-Montreal Global Biodiversity Framework (KMGBF), and regularly evaluated for coverage and impact. Using the EAZA Biobank as an example, we outline the structure, development, and collaborative foundations that have enabled its rapid growth, built on community support and conservation impact. Leveraging EAZA's institutional network and data-sharing platforms such as ZIMS, the Biobank employs a decentralized, four-hub model of zoological institutions storing samples. A gap analysis, integrating threat status, breeding programs, genomic data repositories, and phylogenetic diversity, highlights current sampling strengths and deficiencies and guides future collection priorities. The integration of specimen-specific genomic data and the EAZA Biobank Cryonetwork of institutions with expertise in storing and generating gametes and cell lines will expand the Biobank's role in population management and conservation. Zoological biobanks must now evolve alongside advances in biotechnology and genomics. Sample collection strategies should serve conservation needs and anticipate future applications in genomics, cryobiology, and conservation medicine, linking biospecimens with the wealth of data generated from them. This approach should be scalable beyond EAZA, forming the foundation of a global standardized biobanking framework. Ultimately, zoological biobanks are not merely repositories of the past-they are essential infrastructures shaping the future potential of species conservation.

EAZA↗