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PubMedDate not supplied

Evaluation of the morphological and functional damage to human sperm subjected to freezing at -196 degrees C and to refrigeration at +4 degrees C.

A study was carried out on five healthy, fertile donors to evaluate refrigeration at +4 C compared to cryopreservation at -196 degrees C. These donors had produced more than two pregnancies in different women with their cryopreserved semen in an AID program. The following parameters for evaluation and comparison were used: (i) the percentage of forward sperm motility, (ii) the percentage of swollen sperm after hypoosmotic stress (swelling test) and (iii) the sperm morphology observed both with a light microscope after staining and with an electron microscope. After 48 hours of refrigeration the result obtained were comparable with those observed after one week of cryopreservation. After 72 hours of refrigeration, a sharp and significant decrease of these values was noted. Our data underlined the fact that there is an individual variability in subject response to the method of preservation employed. Our findings show the possibility of using sperm refrigerated for up to 48 hours in AIH programs.

Analysis of Variance↗
PubMed1994

Metabolic activity of bovine articular cartilage during refrigerated storage.

The ability of the chondrocytes in intact bovine articular cartilage (AC) to synthesize glycosaminoglycans (GAG) during short-term refrigerated storage was examined. Closed and exposed bovine carpometacarpal joints were stored in a refrigerator for 4 hours, 1 day, 3 days, 5 days, or 7 days after the death of the animal. Full-thickness 6 mm diameter cartilage disks were obtained from each joint, incubated in Na2(35)SO4, digested and assayed for GAG production. Similarly incubated cartilage samples were processed for autoradiography as a qualitative determination of 35S uptake by chondrocytes. All refrigerated samples of AC showed signs of some cellular metabolic activity. Only at 7 days did chondrocytes demonstrate a significant decline in activity. For all five storage periods, AC from joints exposed to nutrient media synthesized more GAG than cartilage from matched closed joints. These results suggest that some chondrocytes in AC destined for osteoarticular allografting retain the ability to synthesize GAG for as long as 5 days of refrigerated storage and that this synthesis is stimulated by storage of the joint surfaces in a sterile nutrient solution. While the implications of the chondrocytes' survival and metabolism for osteochondral allograft transplantation are unknown, these data indicate that intact bovine AC retains some metabolic activity for several days under the conditions described and would carry on this activity if transplanted within that period of time.

Animals↗
PubMed1995

The use of a topical refrigerant anesthetic to reduce injection pain in children.

Early childhood experiences with painful injections may lead to anxiety and fear. These reactions need not develop if steps are taken to reduce the pain associated with injections. The purpose of this study was to assess the efficacy of a refrigerant topical anesthetic in reducing injection pain in preschool children experiencing routine diphtheria-pertussis-tetanus (DPT) immunizations. This double-blind placebo-controlled study was conducted in community health clinics in conjunction with ongoing immunization programs. Ninety subjects, aged 4-5.5 years, were randomly assigned to one of three groups: (a) refrigerant topical anesthetic; (b) placebo topical spray; and (c) no-spray control. Pain was measured subjectively using a four-point visual analogue scale. Both the refrigerant topical anesthetic spray and the placebo spray significantly reduced injection pain. Age was found to be an important factor influencing pain response in this study. Parental anxiety was not a significant factor influencing pain response. In addition, parents were not good at predicting their child's pain. The results of the study support the use of an intervention, such as refrigerant topical anesthetic, as a practical, simple, and effective treatment strategy for reduction of short-term painful procedures like injections.

Administration, Topical↗
PubMed1985

Prolonged storage of human spermatozoa at room temperature or in a refrigerator.

Spermatozoa from patients who underwent in vitro fertilization (IVF) therapy were prepared free from seminal plasma with the use of IVF culture medium supplemented with 8% human serum. Samples were then stored either at room temperature or in a refrigerator, and their motility and ability to penetrate zona-free hamster eggs were assessed every second day. With storage at room temperature, motility declined by less than half over the first 14 days, with some samples still active 20 days after preparation. The ability of the samples to penetrate hamster eggs was unchanged during the first 6 days of storage, and most of the samples still had positive tests after 14 days. Some spermatozoa could still penetrate after 17 days. Room-temperature-stored spermatozoa were still able to fertilize human oocytes 5 days after preparation. With storage in a refrigerator motility declined rapidly, and few sperm were motile after 14 days. However, these samples penetrated relatively more hamster eggs after 14 days' storage than room-temperature-stored samples did. Spermatozoa stored overnight in a refrigerator had significantly higher hamster egg penetration rates than spermatozoa stored overnight at room temperature. After storage overnight at room temperature, false-positive and false-negative results of hamster egg penetration tests were common in relation to IVF outcome; after refrigerated storage, no false-negative results were found.

Animals↗
PubMed2003

Vitamin C, provitamin A carotenoids, and other carotenoids in high-pressurized orange juice during refrigerated storage.

Vitamin C, provitamin A carotenoids, and other carotenoids were measured in freshly squeezed juices from oranges (Citrus sinensis L. var. Valencia late) that were subjected to high-pressure (HP) treatment. Also, the stability of these compounds was studied during refrigerated storage at 4 degrees C. HP treatment is an alternative to heat preservation methods for foods; therefore, it is essential to assess the impact of HP on bioactive compounds. Several processes that combine HP treatment with heat treatment for various time periods were assayed: T0, fresh juice (without treatment); T1, 100 MPa/60 degrees C/5 min; T2, 350 MPa/30 degrees C/2.5 min; T3, 400 MPa/40 degrees C/1 min. Fresh and treated samples were kept refrigerated (4 degrees C) over 10 days. After application of HP and during the refrigeration period, the qualitative and quantitative determination of vitamin C, provitamin A carotenoids (beta- and alpha-carotene; beta- and alpha-cryptoxanthin), and the xanthophylls zeaxanthin and lutein was achieved by high-performance liquid chromatography. T1 and T3 juices showed a decrease in ascorbic acid and total vitamin C just after HP treatment (D0) compared with T0 juices. On the contrary, T2 juices, just after HP treatment (D0), had the same levels of both compounds compared to untreated juices. T1, T2, and T3 treatments led to an increase in the extraction of carotenoids and provitamin A carotenoids. Total carotenoid content after the 10-day refrigerated storage period resulted in no significant quantitative changes in T1 juices, whereas in T2 and T3 juices small losses were found at the end of the storage period (20.56 and 9.16%, respectively). These losses could be influenced by the depleted protection of vitamin C toward carotenoid oxidation during the same period. A similar trend was found in provitamin A carotenoids for the different treated juices.

Ascorbic Acid↗
PubMed2002

Transition-metal-based magnetic refrigerants for room-temperature applications.

Magnetic refrigeration techniques based on the magnetocaloric effect (MCE) have recently been demonstrated as a promising alternative to conventional vapour-cycle refrigeration. In a material displaying the MCE, the alignment of randomly oriented magnetic moments by an external magnetic field results in heating. This heat can then be removed from the MCE material to the ambient atmosphere by heat transfer. If the magnetic field is subsequently turned off, the magnetic moments randomize again, which leads to cooling of the material below the ambient temperature. Here we report the discovery of a large magnetic entropy change in MnFeP0.45As0.55, a material that has a Curie temperature of about 300 K and which allows magnetic refrigeration at room temperature. The magnetic entropy changes reach values of 14.5 J K-1 kg-1 and 18 J K-1 kg-1 for field changes of 2 T and 5 T, respectively. The so-called giant-MCE material Gd5Ge2Si2 (ref. 2) displays similar entropy changes, but can only be used below room temperature. The refrigerant capacity of our material is also significantly greater than that of Gd (ref. 3). The large entropy change is attributed to a field-induced first-order phase transition enhancing the effect of the applied magnetic field.

Journal Article↗
PubMed1997

Effect of dietary vitamin E on the oxidative stability, flavor, color, and volatile profiles of refrigerated and frozen turkey breast meat.

In this study, the effect of varying dietary vitamin E levels on the oxidative stability, flavor, color, and volatile profiles of refrigerated and frozen turkey breast meat was examined. Nicholas turkey toms were reared on diets containing vitamin E levels as dl-alpha-tocopheryl acetate equivalent to the NRC recommendations (12 and 10 IU/kg from 0 to 8 and 9 to 18 wk, respectively) and 5x, 10x, and 25x the NRC diet. Two other diets were evaluated and included feeding the NRC diet until 15 and 16 wk followed by a diet containing 20x the NRC vitamin E level. All turkeys were processed in a commercial turkey processing plant and breast meat scored for color. Breast meat was excised from four carcasses per treatment and evaluated after refrigeration (1 and 7 d) or frozen storage (30, 90, 150 d) for oxidative stability and sensory quality by TBA analysis, descriptive flavor profiling, and headspace gas chromatography. The TBA values were inversely related to the dietary vitamin E levels. Refrigerated samples had TBA values 78 to 88% lower for the 10x and 25x vitamin E treatments, respectively, than for the NRC control treatment. No differences in TBA values (refrigerated samples) were detected for the 10x, 25x, and 20x (3 wk feeding duration) or across all treatments for samples frozen for 5 mo. The 10x and 25x NRC diets produced the most typical and acceptable turkey meat flavors with the fewest oxidized off-flavor notes for both fresh and frozen samples as opposed to the more oxidized flavor notes detected in the control samples. Mean color scores increased, indicative of less pale meat, as the level and duration of feeding dietary vitamin E increased. These findings showed that varying dietary vitamin E levels significantly influenced the oxidative stability and functionality of turkey breast meat.

Aldehydes↗
PubMed2003

Optimal analysis on the performance of an irreversible harmonic quantum Brayton refrigeration cycle.

An irreversible model of a quantum refrigeration cycle working with many noninteracting harmonic oscillators is established. The refrigeration cycle consists of two adiabatic and two constant-frequency processes. The general performance characteristics of the cycle are investigated, based on the quantum master equation and the semigroup approach. The expressions for several important performance parameters such as the coefficient of performance, cooling rate, power input, and rate of entropy production are derived. By using numerical solutions, the cooling rate of the refrigeration cycle subject to finite cycle duration is optimized. The maximum cooling rate and the corresponding parameters are calculated numerically. The optimal region of the coefficient of performance and the optimal ranges of temperatures of the working substance and times spent on the two constant-frequency processes are determined. Moreover, the optimal performance of the cycle in the high-temperature limit is compared with that of a classical Brayton refrigerator working with an ideal gas. The results obtained here show that in the high-temperature limit a harmonic quantum Brayton cycle may be equivalent to a classical Brayton cycle.

Journal Article↗
PubMed2006

Effects of egg yolk and cooling rate on the survival of refrigerated red deer (Cervus elaphus hispanicus) epididymal spermatozoa.

Egg yolk is a common component to sperm refrigeration for most of the deer species, the role of which is to protect sperm membranes against cold shock. In addition, there have been many studies of conservation of ejaculated semen from stags, but few have been reported for epididymal spermatozoa. This work was designed to investigate the combined effects of cooling rates (slow: 0.23 degrees C/min vs rapid: 4.2 degrees C/min) from room temperature to 5 degrees C, and egg-yolk concentration (0, 5 or 20%) in the extender on the survival of Iberian red deer epididymal spermatozoa refrigerated at 5 degrees C. Heterospermic sperm samples were diluted to a final sperm concentration approximately 400x10(6) sperm/ml with a Tris-citrate-fructose (TCF)-egg-yolk diluent. Sperm quality was in vitro judged by microscopic assessments of individual sperm motility [sperm motility index (SMI)], and of plasma membrane (hypo-osmotic swelling test) and acrosome (NAR) integrities. Our results first showed that the presence of egg yolk in the extender significantly improves (p=0.01) the viability and sperm motility after sperm dilution. In addition, acrosome and plasma membrane integrities post-refrigeration did not differ significantly between cooling procedures; however, the SMI differed significantly between cooling procedures (slow: 46.6% vs rapid: 50.0%; p=0.01). Our results also showed that sperm quality was significantly (p<0.01) affected by the combined effects of egg-yolk concentration and cooling procedure, being rapid cooling with 20% of egg yolk the most suitable combination for epididymal sperm refrigeration. In conclusion, egg-yolk improved red deer epididymal spermatozoa characteristics after dilution. Rapid cooling protocol using TCF with 20% egg-yolk significantly improved sperm motility of red deer epididymal spermatozoa after cooling.

Animals↗
PubMedDate not supplied

Safety and tolerability of a 'refrigeration-free' formulation of interferon beta-1b--results of a double-blind, multicentre, comparative study in patients with relapsing-remitting or secondary progressive multiple sclerosis.

The original glucose-based formulation of Betaferon/Betaseron (interferon beta-1b) requires refrigerated storage. A refrigeration-free formulation of interferon beta-1b, based on mannitol, is stable at room temperature for up to 2 years, and offers a greater degree of flexibility for patients with multiple sclerosis (MS). We compared the safety and tolerability of the two formulations in a 24-week, randomized, double-blind, parallel group, Phase IV clinical study conducted in 303 patients with MS. Patients received the glucose formulation (IFNbeta-1b-G) for 8 weeks, and were then randomized to receive either IFNbeta-1b-G or the refrigeration-free formulation (IFNbeta-1b-M) for a further 8 weeks. On completion of the double-blind phase, all patients received IFNbeta-1b-M for an 8-week follow-up period. The primary outcome measure was the proportion of injection sites that developed reactions per patient during the double-blind period. In addition, a range of secondary outcomes relating to these reactions was also assessed. The difference in the proportion of injection-site reactions between the two groups was not statistically significant (59% IFNbeta-1b-G versus 60% IFNbeta-1b-M). There were no statistically significant differences observed between the two treatment groups in any of the secondary tolerability endpoints. The results from this study demonstrate that the tolerability and safety profiles of both formulations are extremely good, and that the refrigeration-free formulation of interferon beta-1b is comparable with that of the original glucose formulation.

Adjuvants, Immunologic↗
PubMed2000

Stability of common analytes in urine refrigerated for 24 h before automated analysis by test strips.

BACKGROUND: Central outpatient laboratories might find processing large numbers of urinary samples that arrive in the late afternoon inconvenient and refrigerate them overnight before testing. Furthermore, in certain settings clinics might have difficulty assuring that the urine arrives at the laboratory during the same day as the collection. Because the stability of urine samples for delayed automated dipstick analysis (Supertron) is unknown, after defining precision, we retested urines refrigerated for 24 h to determine stability. METHODS: Urinalysis was done twice on the same day and repeated after the sample was refrigerated for 24 h. Combur-10S (Roche Diagnostics) dipsticks were read automatically by a Supertron analyzer. Repeat tests on the same day were compared with tests after storage. RESULTS: Leukocyte esterase had high precision, but after storage approximately 25% of the positive samples were less reactive (P: <0.005). Precision of hemoglobin retests was also high but declined significantly after storage for 24 h. Urine protein values increased after storage. The precision and stability were excellent for nitrites, glucose, and ketones. CONCLUSIONS: The stability of the automated dipstick urinalysis varies with the substance tested. After refrigeration for 24 h, there is a risk of false-positive results for protein, false-negative results for leukocytes and erythrocytes, and little effect on glucose, nitrite, and ketone values.

Autoanalysis↗
PubMedDate not supplied

Recovery of Salmonella spp. from refrigerated preenrichment cultures of dry food composites.

Refrigerated preenrichment 72 h and selective enrichment cultures arising from 25 g analytical units of dry foods can be used to increase the analytical flexibility and productivity of laboratories for the detection of foodborne Salmonella spp. by AOAC method 994.04. Results of this intralaboratory study using artificially contaminated dry foods validate the extended application of the refrigerated preenrichment approach to dry food composites (375 g). All samples found to be contaminated by AOAC/Bacteriological Analytical Manual methods were identified readily from the homologous, refrigerated preenrichment broth cultures. This extended application of the refrigeration approach was recently adopted First Action by AOAC and was included as a modification to method 994.04. In addition, ancillary work on the diagnostic value of prolonged (48 h) incubation of lysine iron (LI) agar as described in the AOAC Official Method 967.26 led to a recommendation that the 48 h period of incubation be revoked in favor of a 24 h incubation of inoculated LI medium.

Cold Temperature↗
PubMed2006

Reduced potency after refrigerated storage of botulitum toxin A: human extensor digitorum brevis muscle study.

To determine whether the potency of botulinum toxin A (BTA) decreases after being reconstituted with normal saline and stored in refrigerator, we injected one side of the extensor digitorum brevis muscle with 2.5 units of botulinum toxin A that had been immediately reconstituted with saline, and the contralateral side with identical material that had been reconstituted and stored in a refrigerator for preselected periods (1, 2, and 4 weeks) in 32 healthy volunteers. Mean compound muscle action potential amplitudes expressed as a percentage of the baseline amplitude were more reduced in sides injected with immediately reconstituted BTA than in sides injected with BTA stored for 1 week or more (P < 0.05). No bacterial growth was observed in any stored BTA samples. Storage of reconstituted BTA at low temperatures may affect the potency of the toxin. Therefore, the use of BTA after refrigerated storage is not recommended.

Adult↗
PubMedDate not supplied

Refrigeration of blood samples prior to separation is essential for the accurate determination of plasma or serum zinc concentrations.

An evaluation of refrigeration (7 degrees C) to prevent falsely high plasma or serum zinc concentrations owing to elapsed time between blood collection and centrifugation was performed. At room temperature (23 degrees C), both plasma and serum zinc concentrations increased significantly, if blood samples were stored uncentrifuged. Plasma zinc concentrations increased 6.3% at 1 h and 40.7% at 24 h, whereas serum zinc concentrations increased only 0.9% at 1 h and 12.5% at 24 h at room temperature. When blood samples were stored uncentrifuged in the refrigerator for up to 24 h, there were no significant increases in zinc concentrations in either plasma or serum. These findings suggest that plasma or serum separation should be performed immediately after blood drawing to obtain accurate zinc concentrations, and if this is not feasible, the samples should be immediately refrigerated and separation performed within eight hours.

Adult↗
PubMed1991

Refrigerated food storage in hospital ward areas.

A survey of ward refrigerators was carried out in two hospitals, with reference to type and efficiency in maintaining cold storage temperatures. A total of 40 refrigerators were surveyed on two occasions. Only seven were found to maintain temperatures between 5 degrees C and 7 degrees C. Commercial larder type refrigerators are recommended for ward use. Training and updating of staff in policies and procedures is emphasized.

Data Collection↗
PubMed2005

Effect of osmotic immobilization on refrigerated storage and cryopreservation of sperm from a viviparous fish, the green swordtail Xiphophorus helleri.

In this study, refrigerated storage and cryopreservation of sperm from the green swordtail Xiphophorus helleri were investigated. Previous cryopreservation research in this species utilized motile sperm because unlike in most fish species, Xiphophorus sperm can remain continuously motile after collection for a week with refrigerated storage. However, this species reproduces by internal fertilization, and given the significant requirements for motility within the female reproductive tract and potential limitations on sperm energetic capacities, immobilization of sperm prior to insemination could be used to improve fertilization success. Thus, the goal in this study was to use osmotic pressure to inhibit the motility of sperm after collection from X. helleri, and to test the effect of immobilization on refrigerated storage and cryopreservation. The objectives were to: (1) estimate the motility of sperm at different osmotic pressures, and determine an osmotic pressure suitable for immobilization; (2) cryopreserve the immobilized sperm, and estimate the motility after thawing with or without dilution, and (3) compare motility of non-immobilized and immobilized sperm after thawing, centrifugation, and washing to remove cryoprotectant. Motility was determined when sperm were suspended in 11 different osmotic pressures (24-500 mOsmol/kg) of Hanks' balanced salt solution (HBSS). Motility was observed between 116 and 425 mOsmol/kg. Sperm were not motile when the osmolality was lower than 116 or higher than 425 mOsmol/kg. Motility of the immobilized (non-motile) sperm could be activated by changing the osmotic pressure to 291-316 mOsmol/kg, and motility of immobilized sperm from hypertonic HBSS (425 mOsmol/kg) was significantly higher than that from hypotonic HBSS (145 mOsmol/kg) after 48 h of storage. At an osmolality of 500 mOsmol/kg, HBSS was used as extender to maintain immobilized sperm during cryopreservation with glycerol as the cryoprotectant. High motility (approximately 55%) was obtained in sperm after thawing when cryopreserved with 10-15% glycerol, and dilution of thawed sperm in fresh HBSS (1:4; V:V) was found to decrease the motility significantly. No difference was found in the motility of thawed sperm cryopreserved with 14% glycerol and extended in 310 and 500 mOsmol/kg HBSS. Washing by centrifugation prolonged the motility of thawed sperm from 24 to 72 h in HBSS at 310 and 500 mOsmol/kg. This study showed that sperm from X. helleri could be immobilized by use of specific osmotic pressures, and that the immobilization did not affect sperm motility after thawing. The immobilization of sperm by osmotic pressure could minimize reduction of the energetic capacities necessary for insemination, traversal, and residence within the female reproductive tract, and fertilization.

Animals↗
PubMed2002

Survival of nonsporulated Toxoplasma gondii oocysts under refrigerator conditions.

Toxoplasma gondii oocysts are excreted nonsporulated in the feces of the cats into the environment. These oocysts must undergo sporulation to become infectious. Little is known about the factors that influence sporulation of T. gondii oocysts. The present study examined the survival of nonsporulated oocysts under refrigerated conditions over 11-week observation period. Microscopic examination of oocysts indicated that no visible development occurred under refrigerator conditions. The nonsporulated oocysts retained their ability to sporulate when placed at room temperature. The numbers of visually viable appearing oocysts decreased over time. Some oocysts in all samples were infectious for mice despite being refrigerated for up to an 11 weeks before undergoing sporulation. Results indicate that nonsporulated oocysts can survive in the environment for at least 3 months and retain their ability to become infectious when placed under appropriate conditions.

Animals↗
PubMed1999

Bacterial resistance of refrigerated and cryopreserved aortic allografts in an experimental virulent infection model.

PURPOSE: The bacterial resistance of refrigerated and cryopreserved aortic allografts in a highly virulent infection in a dog model was studied. METHODS: The infrarenal aorta of 12 dogs was replaced with either a cryopreserved aortic allograft (group I, n = 6) or a refrigerated aortic allograft (group II, n = 6) in infected sites. Allografts were harvested from dogs and stored for 1 week, either by cryopreservation (-140 degrees C) or refrigerated method (4 degrees C), in a preservation medium. At the time of implantation, induction of infection was achieved with an infected piece of knitted Dacron placed just beneath the allograft. The Dacron was contaminated in vitro by soaking it in a solution with Staphylococcus aureus PR209. All 12 dogs received no adjunct antibiotic or antithrombotic therapy. Four weeks after implantation, the animals were killed to recover the grafts for bacteriological and histological analyses. Bacterial results were expressed as colony-forming units (CFU)/cm2 of graft material. RESULTS: In group I, only one allograft grew bacteria at 2. 16 x 10(6 )CFU/cm2, with a blood culture positive for S aureus. In group II, one dog died at 3 weeks from a false septic aneurysm rupture, all the allografts were infected (P <.05) with a mean bacterial count of 9.41 +/- 6.8 x 10(4) CFU/cm2, and three blood cultures were positive for S aureus. The patency of the grafts was analyzed at the time of recovery. Three laminar thrombi without occlusion were present in group I; none were present in group II. A better preserved endothelium in group I was revealed by means of histologic analysis staining with factor VIII antibody before implantation. After 4 weeks of implantation in the infected site, infected allografts presented polynuclear infiltrates in the media with a high degree of inflammatory reaction, and endothelial recovery was more significant in group I, with numerous young plump cells. CONCLUSION: This study demonstrates that cryopreserved allografts implanted in infected sites in a dog model can produce greater bacterial resistance.

Animals↗