Cryopreservation of gonadal tissue and cells.
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With the advent of assisted reproductive technology and an improved understanding of cryobiology, strategies have been developed which allow the long-term storage of gametes and embryos. Furthermore, in the light of the growing numbers of young adults and children who have been sterilised by successful cancer treatment, the need to protect their fertile potential has become more urgent. While semen cryopreservation is available for men, the methods for preserving oocytes are unreliable and neither method is suitable for prepubertal children. Research attention is, therefore, focusing on the low temperature banking of immature germ cells with the aim to restore natural fertility if possible or, alternatively, to use culture technology to produce ripe gametes for assisted conception. While there is no universal method for fertility conservation, gonadal tissue banking, in theory, is a practical alternative to gamete storage which can be utilised by both adults and children. (+info)
Cinnamophilin as a novel antiperoxidative cytoprotectant and free radical scavenger.
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The antioxidant properties of cinnamophilin were evaluated by studying its ability to react with relevant reactive oxygen species, and its protective effect on cultured cells and biomacromolecules under oxidative stress. Cinnamophilin concentration-dependently suppressed non-enzymatic iron-induced lipid peroxidation in rat brain homogenates with an IC50 value of 8.0+/-0.7 microM and iron ion/ADP/ascorbate-initiated rat liver mitochondrial lipid peroxidation with an IC50 value of 17.7+/-0.2 microM. It also exerted an inhibitory activity on NADPH-dependent microsomal lipid peroxidation with an IC50 value of 3.4+/-0.1 microM without affecting microsomal electron transport of NADPH-cytochrome P-450 reductase. Both 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azo-bis(2-amidinopropane) dihydrochloride-derived peroxyl radical tests demonstrated that cinnamophilin possessed marked free radical scavenging capacity. Cinnamophilin significantly protected cultured rat aortic smooth muscle cells (A7r5) against alloxan/iron ion/H2O2-induced damage resulting in cytoplasmic membranous disturbance and mitochondrial potential decay. By the way, cinnamophilin inhibited copper-catalyzed oxidation of human low-density lipoprotein, as measured by fluorescence intensity and thiobarbituric acid-reactive substance formation in a concentration-dependent manner. On the other hand, it was reactive toward superoxide anions generated by the xanthine/xanthine oxidase system and the aortic segment from aged spontaneously hypertensive rat. Furthermore, cinnamophilin exerted a divergent effect on the respiratory burst of human neutrophil by different stimulators. Our results show that cinnamophilin acts as a novel antioxidant and cytoprotectant against oxidative damage. (+info)
Rat liver responsiveness to gluconeogenic substrates during insulin-induced hypoglycemia.
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Hepatic responsiveness to gluconeogenic substrates during insulin-induced hypoglycemia was investigated. For this purpose, livers were perfused with a saturating concentration of 2 mM glycerol, 5 mM L-alanine or 5 mM L-glutamine as gluconeogenic substrates. All experiments were performed 1 h after an ip injection of saline (CN group) or 1 IU/kg of insulin (IN group). The IN group showed higher (P<0.05) hepatic glucose production from glycerol, L-alanine and L-glutamine and higher (P<0.05) production of L-lactate, pyruvate and urea from L-alanine and L-glutamine. In addition, ip injection of 100 mg/kg glycerol, L-alanine and L-glutamine promoted glucose recovery. The results indicate that the hepatic capacity to produce glucose from gluconeogenic precursors was increased during insulin-induced hypoglycemia. (+info)
A novel cryoprotective protein (CRP) with high activity from the ice-nucleating bacterium, Pantoea agglomerans IFO12686.
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The ice-nucleating bacterium, Pantoea agglomerans IFO12686, induces the cryoprotective protein (CRP) by cold acclimation at 12 degrees C. The CRP was purified to apparent homogeneity by various chromatographies. We found that the purified CRP was a monomer of approximately 29,000 according to gel filtration chromatography and SDS-PAGE, and was a heat-stable protein. The CRP could protect freeze-labile enzymes, lactate dehydrogenase (LDH), alcohol dehydrogenase (ADH) and isocitrate dehydrogenase (iCDH), against freezing-thawing denaturation. The activity of the CRP was about 3.5 x 10(4) times more effective than bovine serum albumin (BSA) and 2 x 10(6) times than COR26 from the ice-nucleating bacterium Pseudomonas fluorescens KUIN-1. We confirmed that the CRP was a novel protein, as judged by the a different molecule mass from the already-known cryoprotectants, and has an extremely high cryoprotective activity. (+info)
Cryoprotective effect of the serine-rich repetitive sequence in silk protein sericin.
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The silk proteins, fibroin and sericin, are produced in the silk gland of Bombyx mori, and hydrophilic sericin envelops fibroin with successive sticky layers in the formation of a cocoon. To study the biological functions of sericin, we focused on the serine-rich sericin peptide consisting of 38 amino acids, which is a highly conserved and internally repetitive sequence of a sericin protein. The corresponding gene was chemically synthesized, and the PCR-amplified gene was ligated to oligomerize sericin peptide and fused at the amino terminus to a His-tagged and proteolytic cleavage sequence in an inducible expression vector. When the dimers of sericin peptides were overexpressed in Escherichia coli, the transformants showed a prominent increase in cell viability after freezing in medium. Further, the purified dimeric sericin peptide from E. coli was found to be effective in protecting lactate dehydrogenase from denaturation caused by freeze-thaw. Both of these protective effects against freezing stress in cells and proteins were also observed with sericin hydrolysate. These results indicate that this unique sericin peptide, like sericin, has a high cryoprotective activity and will be valuable as a new biomaterial for industrial use. (+info)
A comparative study of preservation and storage of Haemophilus influenzae.
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The aim of this study was to compare the efficacy of conservation by freezing the strains of Haemophilus influenzae at -20 degrees C and -70 degrees C. Skim milk supplemented with glucose, yeast extract and glycerol allowed highest viability of H. influenzae both at -20 degrees C and -70 degrees C from the media analyzed. Trypticase soy broth and brain heart infusion broth supplemented with glycerol, allowed excellent recovery. Use of cotton swaps as supporting material, with or without addition of cryoprotective agents, did not modify H. influenzae viability after six months of storage. Concentration of the initial inoculum positively affected viability when stored at -20 degrees C. Initial concentration did not influence survival after storage at -70 degrees C. Thawing at room temperature should not exceed 3 h as to get highest survival percentage. (+info)
Rapid cold-hardening of Drosophila melanogaster (Diptera: Drosophiladae) during ecologically based thermoperiodic cycles.
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In contrast to most studies of rapid cold-hardening, in which abrupt transfers to low temperatures are used to induce an acclimatory response, the primary objectives of this study were to determine (i) whether rapid cold-hardening was induced during the cooling phase of an ecologically based thermoperiod, (ii) whether the protection afforded was lost during warming or contributed to increased cold-tolerance during subsequent cycles and (iii) whether the major thermally inducible stress protein (Hsp70) or carbohydrate cryoprotectants contributed to the protection afforded by rapid cold-hardening. During the cooling phase of a single ecologically based thermoperiod, the tolerance of Drosophila melanogaster to 1 h at -7 degrees C increased from 5 +/- 5% survival to 62.5 +/- 7.3% (means +/- S.E.M., N=40-60), while their critical thermal minima (CTmin) decreased by 1.9 degrees C. Cold hardiness increased with the number of thermoperiods to which flies were exposed; i.e. flies exposed to six thermoperiods were more cold-tolerant than those exposed to two. Endogenous levels of Hsp70 and carbohydrate cryoprotectants were unchanged in rapidly cold-hardened adults compared with controls held at a constant 23 degrees C. In nature, rapid cold-hardening probably affords subtle benefits during short-term cooling, such as allowing D. melanogaster to remain active at lower temperatures than they otherwise could. (+info)
Intensified chemotherapy supported by DMSO-free peripheral blood progenitor cells in breast cancer patients.
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BACKGROUND: The majority of high-dose chemotherapy (HDC)-related complications results from bone marrow aplasia, but the graft infusion per se may cause adverse reactions due to the injection of both dimethyl sulfoxide (DMSO) and cell lysis products. We evaluated the feasibility of a two-step chemotherapy regimen with peripheral blood progenitor cell (PBPC) support in association with a novel procedure to remove DMSO and products of cell lysis from the cryopreserved cells. PATIENTS AND METHODS: Stage III and IV breast cancer patients received induction chemotherapy with three cycles of CEF (cyclophosphamide 600 mg/m2, epirubicin 100 mg/m2, 5-fluorouracil 600 mg/m2) followed by three cycles of HDC consisting of escalating doses of cyclophosphamide (dose range 1200 3000 mg/m2) and carboplatin (dose range 600-1000 mg/m2), supported by DMSO-free PBPC reinfusion. DMSO was removed by a washing/enzymatic digestion procedure. RESULTS: Twenty patients received induction chemotherapy and eighteen completed the entire chemotherapy program; a total of fifty-four cycles of HDC were administered. Dose limiting toxicity of HDC was long-lasting grade 4 neutropenia associated with documented infection. The maximum tolerated dose (MTD) was cyclophosphamide 3000 mg/m2 and carboplatin 600 mg/m2. No side effects related to PBPC reinfusion were observed. CONCLUSIONS: The proposed two-step chemotherapy regimen, associated with a novel washing/enzymatic digestion procedure, is feasible in advanced breast cancer patients in the absence of complications related to the specific toxicity of PBPC reinfusion. (+info)