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Publication
Journal: Journal of Immunological Methods
February/26/2006
Abstract
The ability to cryopreserve lymphocytes in peripheral blood mononuclear cells (PBMC) to retain their function after thawing is critical to the analysis of cancer immunotherapy studies. We evaluated a variety of cryopreservation strategies with the aim of developing an optimized protocol for freezing and thawing PBMC to retain viability and function. We determined several factors which do not affect cell viability after cryopreservation such as shipping frozen samples on dry ice, the length of time and speed at which samples are washed and centrifuged after thawing, and the number of cells frozen per container. Different media additives, however, did impact the viability of the cells after thawing. There was a significant reduction in the viability of the cells after freezing when using human AB serum compared to all other additives tested (p<0.000). A second critical parameter was the temperature of the media used to wash the cells after removal from the cryotubes. When the media was cooled to 4 degrees C prior to washing, the mean viability was 69.7+/-12.5%, at 25 degrees C 92.55+/-3.1%, and at 37 degrees C 95.11+/-2.5%. Finally, we used an optimized cryopreservation protocol with different media additives to determine if functional T cell responses to tetanus toxoid could be preserved. There was a statistically significant correlation between the tetanus specific stimulation index (S.I.) of the non-cryopreserved PBMC and SI obtained from cells frozen with media containing human serum albumin as compared to other additives such as dextran or fetal bovine serum.
Publication
Journal: Pain
December/25/2006
Abstract
Visceral pain processing is abnormal in a majority of irritable bowel syndrome (IBS) patients. Aberrant endogenous nociceptive modulation and anticipation are possible underlying mechanisms investigated in the current study. Twelve IBS patients and 12 matched healthy controls underwent brain fMRI scanning during the following randomised stimuli: sham and painful rectal distensions by barostat without and with simultaneous activation of endogenous descending nociceptive inhibition using ice water immersion of the foot for heterotopic stimulation. Heterotopic stimulation decreased rectal pain scores from 3.7+/-0.2 to 3.1+/-0.3 (mean+/-SE, scale 0-5) in controls (p<0.01), but not significantly in IBS. Controls differed from IBS patients in showing significantly greater activation bilaterally in the anterior insula, SII and putamen during rectal stimulation alone compared to rectal plus heterotopic stimulation. Greater activation during rectal plus heterotopic versus rectal stimulation was seen bilaterally in SI and the right superior temporal gyrus in controls and in the right inferior lobule and bilaterally in the superior temporal gyrus in IBS. Rectal pain scores were similarly low during sham stimulation in both groups, but brain activation patterns differed. In conclusion, IBS patients showed dysfunctional endogenous inhibition of pain and concomitant aberrant activation of brain areas involved in pain processing and integration. Anticipation of rectal pain was associated with different brain activation patterns in IBS involving multiple interoceptive, homeostatic, associative and emotional areas, even though pain scores were similar during sham distension. The aberrant activation of endogenous pain inhibition appears to involve circuitry relating to anticipation as well as pain processing itself.
Publication
Journal: Journal of Cell Biology
February/9/1998
Abstract
There is increasing evidence that programmed cell death (PCD) depends on a novel family of intracellular cysteine proteases, called caspases, that includes the Ced-3 protease in the nematode Caenorhabditis elegans and the interleukin-1beta-converting enzyme (ICE)-like proteases in mammals. Some developing cells, including lens epithelial cells, erythroblasts, and keratinocytes, lose their nucleus and other organelles when they terminally differentiate, but it is not known whether the enzymatic machinery of PCD is involved in any of these normal differentiation events. We show here that at least one CPP32 (caspase-3)-like member of the caspase family becomes activated when rodent lens epithelial cells terminally differentiate into anucleate lens fibers in vivo, and that a peptide inhibitor of these proteases blocks the denucleation process in an in vitro model of lens fiber differentiation. These findings suggest that at least part of the machinery of PCD is involved in lens fiber differentiation.
Publication
Journal: Conservation Biology
October/26/2008
Abstract
Different components of global environmental change are typically studied and managed independently, although there is a growing recognition that multiple drivers often interact in complex and nonadditive ways. We present a conceptual framework and empirical review of the interactive effects of climate change and invasive species in freshwater ecosystems. Climate change is expected to result in warmer water temperatures, shorter duration of ice cover, altered streamflow patterns, increased salinization, and increased demand for water storage and conveyance structures. These changes will alter the pathways by which non-native species enter aquatic systems by expanding fish-culture facilities and water gardens to new areas and by facilitating the spread of species during floods. Climate change will influence the likelihood of new species becoming established by eliminating cold temperatures or winter hypoxia that currently prevent survival and by increasing the construction of reservoirs that serve as hotspots for invasive species. Climate change will modify the ecological impacts of invasive species by enhancing their competitive and predatory effects on native species and by increasing the virulence of some diseases. As a result of climate change, new prevention and control strategies such as barrier construction or removal efforts may be needed to control invasive species that currently have only moderate effects or that are limited by seasonally unfavorable conditions. Although most researchers focus on how climate change will increase the number and severity of invasions, some invasive coldwater species may be unable to persist under the new climate conditions. Our findings highlight the complex interactions between climate change and invasive species that will influence how aquatic ecosystems and their biota will respond to novel environmental conditions.
Publication
Journal: Science
March/8/2009
Abstract
About 34 million years ago, Earth's climate shifted from a relatively ice-free world to one with glacial conditions on Antarctica characterized by substantial ice sheets. How Earth's temperature changed during this climate transition remains poorly understood, and evidence for Northern Hemisphere polar ice is controversial. Here, we report proxy records of sea surface temperatures from multiple ocean localities and show that the high-latitude temperature decrease was substantial and heterogeneous. High-latitude (45 degrees to 70 degrees in both hemispheres) temperatures before the climate transition were approximately 20 degrees C and cooled an average of approximately 5 degrees C. Our results, combined with ocean and ice-sheet model simulations and benthic oxygen isotope records, indicate that Northern Hemisphere glaciation was not required to accommodate the magnitude of continental ice growth during this time.
Publication
Journal: American Journal of Sports Medicine
May/18/2016
Abstract
BACKGROUND
The epidemiology of sports-related concussion (SRC) among student-athletes has been extensively researched. However, recent data at the collegiate level are limited.
OBJECTIVE
To describe the epidemiology of SRC in 25 National Collegiate Athletic Association (NCAA) sports.
METHODS
Descriptive epidemiology study.
METHODS
SRC data from the NCAA Injury Surveillance Program during the 2009-2010 to 2013-2014 academic years were analyzed. Concussion injury rates, rate ratios (RRs), and injury proportion ratios were reported with 95% CIs. National estimates were also calculated to examine linear trends across time.
RESULTS
During the study period, 1670 SRCs were reported, representing a national estimate of 10,560 SRCs reported annually. Among the 25 sports, the overall concussion rate was 4.47 per 10,000 athlete-exposures (AEs) (95% CI, 4.25-4.68). Overall, more SRCs occurred in competitions (53.2%). The competition rate (12.81 per 10,000 AEs) was larger than the practice rate (2.57 per 10,000 AEs) (competition vs practice, RR = 4.99; 95% CI, 4.53-5.49). Of all SRCs, 9.0% were recurrent. Most SRCs occurred from player contact (68.0%). The largest concussion rates were in men's wrestling (10.92 per 10,000 AEs; 95% CI, 8.62-13.23), men's ice hockey (7.91 per 10,000 AEs; 95% CI, 6.87-8.95), women's ice hockey (7.50 per 10,000 AEs; 95% CI, 5.91-9.10), and men's football (6.71 per 10,000 AEs; 95% CI, 6.17-7.24). However, men's football had the largest annual estimate of reported SRCs (n = 3417), followed by women's soccer (n = 1113) and women's basketball (n = 998). Among all SRCs, a linear trend did not exist in national estimates across time (P = .17). However, increases were found within specific sports, such as men's football, women's ice hockey, and men's lacrosse.
CONCLUSIONS
The estimated number of nationally reported SRCs has increased within specific sports. However, it is unknown whether these increases are attributable to increased reporting or frequency of concussions. Many sports report more SRCs in practice than in competition, although competition rates are higher. Men's wrestling and men's and women's ice hockey have the highest reported concussion rates. Men's football had the highest annual national estimate of reported SRCs, although the annual participation count was also the highest. Future research should continue to longitudinally examine SRC incidence while considering differences by sex, division, and level of competition.
Publication
Journal: Applied and Environmental Microbiology
October/31/2005
Abstract
Individual strains of the plant pathogenic bacterium Pseudomonas syringae vary in their ability to produce toxins, nucleate ice, and resist antimicrobial compounds. These phenotypes enhance virulence, but it is not clear whether they play a dominant role in specific pathogen-host interactions. To investigate the evolution of these virulence-associated phenotypes, we used functional assays to survey for the distribution of these phenotypes among a collection of 95 P. syringae strains. All of these strains were phylogenetically characterized via multilocus sequence typing (MLST). We surveyed for the production of coronatine, phaseolotoxin, syringomycin, and tabtoxin; for resistance to ampicillin, chloramphenicol, rifampin, streptomycin, tetracycline, kanamycin, and copper; and for the ability to nucleate ice at high temperatures via the ice-nucleating protein INA. We found that fewer than 50% of the strains produced toxins and significantly fewer strains than expected produced multiple toxins, leading to the speculation that there is a cost associated with the production of multiple toxins. None of these toxins was associated with host of isolation, and their distribution, relative to core genome phylogeny, indicated extensive horizontal genetic exchange. Most strains were resistant to ampicillin and copper and had the ability to nucleate ice, and yet very few strains were resistant to the other antibiotics. The distribution of the rare resistance phenotypes was also inconsistent with the clonal history of the species and did not associate with host of isolation. The present study provides a robust phylogenetic foundation for the study of these important virulence-associated phenotypes in P. syringae host colonization and pathogenesis.
Publication
Journal: Journal of Virology
September/9/1996
Abstract
Baculovirus p35 prevents programmed cell death in diverse organisms and encodes a protein inhibitor (P35) of the CED-3/interleukin-1 beta-converting enzyme (ICE)-related proteases. By using site-directed mutagenesis, we have identified P35 domains necessary for suppression of virus-induced apoptosis in insect cells, the context in which P35 evolved. During infection, P35 was cleaved within an essential domain at or near the site DQMD-87G required for cleavage by CED-3/ICE family proteases. Cleavage site substitution of alanine for aspartic acid at position 87 (D87A) of the P1 residue abolished P35 cleavage and antiapoptotic activity. Although the P4 residue substitution D84A also caused loss of apoptotic suppression, it did not eliminate cleavage and suggested that P35 cleavage is not sufficient for antiapoptotic activity. Apoptotic insect cells contained a CED-3/ICE-like activity that cleaved in vitro-translated P35 and was inhibited by recombinant wild-type P35 but not P1- or P4-mutated P35. Thus, baculovirus infection directly or indirectly activates a novel CED-3/ICE-like protease that is inhibited by P35, thereby preventing virus-induced apoptosis. Our findings confirmed the inhibitory activity of P35 towards the CED-3/ICE protease, including recombinant mammalian enzymes, and were consistent with a mechanism involving P35 stoichiometric interaction and cleavage. P35's inhibition of phylogenetically diverse proteases accounts for its general effectiveness as an apoptotic suppressor.
Publication
Journal: International Immunology
September/6/2004
Abstract
Caspase-1 [IL-1beta-converting enzyme (ICE)] processes substrate precursor molecules to yield the biologically active form of IL-1beta and IL-18, both of which are considered to play important roles in the host defense by activation of both innate and adaptive immunity. We evaluated the immune response of caspase-1(-/-) mice to Listeria monocytogenes (LM) infection. LM eradication in the early phase of infection was impaired in the mutant mice with a prominent decrease in IL-18 and IFN-gamma production, but not in IL-12. Caspase-1(-/-) spleen cells including dendritic cells and NK cells produced less IFN-gamma in response to heat-killed LM than wild-type cells in vitro. IFN-gamma production and bactericidal activity in LM-infected caspase-1(-/-) mice was reconstituted to normal levels by adding back IL-18 at the initial phase of infection, suggesting that the lack of this cytokine is primarily responsible for the susceptibility of caspase-1(-/-) mice against LM infection. Moreover, IFN-gamma injection of caspase-1(-/-) mice corrected the deficiency in pathogen clearance. In contrast, LM-specific acquired immunity in caspase-1(-/-) mice was normal and they successfully cleared the pathogen following secondary infection, in spite of a moderate skewing of cytokine profile to T(h)2 when compared to wild-type mice. These data shed light on the importance of caspase-1-mediated IL-18 processing in innate immunity against facultative intracellular pathogens.
Publication
Journal: Nature
September/28/2005
Abstract
Polar organisms have adapted their seasonal cycles to the dynamic interface between ice and water. This interface ranges from the micrometre-sized brine channels within sea ice to the planetary-scale advance and retreat of sea ice. Polar marine ecosystems are particularly sensitive to climate change because small temperature differences can have large effects on the extent and thickness of sea ice. Little is known about the interactions between large, long-lived organisms and their planktonic food supply. Disentangling the effects of human exploitation of upper trophic levels from basin-wide, decade-scale climate cycles to identify long-term, global trends is a daunting challenge facing polar bio-oceanography.
Publication
Journal: American Journal of Sports Medicine
January/5/2011
Abstract
BACKGROUND
Hip injuries are common among professional hockey players in the National Hockey League (NHL).
OBJECTIVE
Professional hockey players will return to a high level of function and ice hockey after arthroscopic labral repair and treatment of femoroacetabular impingement.
METHODS
Case series; Level of evidence, 4.
METHODS
Twenty-eight professional hockey players (NHL) were unable to perform at the professional level due to unremitting and debilitating hip pain. Players underwent arthroscopic labral repair and were treated for femoroacetabular impingement from March 2005 to December 2007. Players who had bilateral hip symptoms were excluded. Athletes completed the Modified Harris Hip Score preoperatively and postoperatively and also completed a patient satisfaction questionnaire postoperatively. Return to sport was defined as the player resuming skating for training or participation in the sport of ice hockey.
RESULTS
The average age at the time of surgery was 27 years (range, 18-37). There were 11 left hips and 17 right hips. Player positions included 9 defensemen, 12 offensive players, and 7 goaltenders. All players had labral lesions that required repair. In addition, all patients had evidence of femoroacetabular impingement at the time of surgery. The average time to return to skating/hockey drills was 3.4 months. The average time to follow-up was 24 months (range, 12-42). The Modified Harris Hip Score improved from 70 (range, 57-100) preoperatively to an average of 95 (range, 74-100) at follow-up. The median patient satisfaction was 10 (range, 5-10). Two players had reinjury and required additional hip arthroscopy.
CONCLUSIONS
Treatment of femoroacetabular impingement and labral lesions in professional hockey players resulted in successful outcomes, with high patient satisfaction and prompt return to sport.
Publication
Journal: Genes and Development
October/17/2001
Abstract
Imprinting of the maternally-expressed Igf2r gene is controlled by an intronic imprint control element (ICE) known as Region2 that contains the promoter of the noncoding Air RNA, whose transcript overlaps the silenced paternal Igf2r promoter in an antisense orientation. Two novel imprinted genes, Slc22a2 and Slc22a3 are described here that lie 110 and 155 kb 3' to Igf2r and that are not overlapped by the Air transcript but are regulated by the Igf2r-ICE, as previously shown for Igf2r. These results identify a new cluster of imprinted genes whose repression by the bidirectional action of the Region2-ICE is independent of transcript overlap by the Air RNA.
Publication
Journal: Journal of Bacteriology
April/9/2006
Abstract
The current perception of the ultrastructure of gram-positive cell envelopes relies mainly on electron microscopy of thin sections and on sample preparation. Freezing of cells into a matrix of amorphous ice (i.e., vitrification) results in optimal specimen preservation and allows the observation of cell envelope boundary layers in their (frozen) hydrated state. In this report, cryo-transmission electron microscopy of frozen-hydrated sections of Staphylococcus aureus D2C was used to examine cell envelope organization. A bipartite wall was positioned above the plasma membrane and consisted of a 16-nm low-density inner wall zone (IWZ), followed by a 19-nm high-density outer wall zone (OWZ). Observation of plasmolyzed cells, which were used to artificially separate the membrane from the wall, showed membrane vesicles within the space associated with the IWZ in native cells and a large gap between the membrane and OWZ, suggesting that the IWZ was devoid of a cross-linked polymeric cell wall network. Isolated wall fragments possessed only one zone of high density, with a constant level of density throughout their thickness, as was previously seen with the OWZs of intact cells. These results strongly indicate that the IWZ represents a periplasmic space, composed mostly of soluble low-density constituents confined between the plasma membrane and OWZ, and that the OWZ represents the peptidoglycan-teichoic acid cell wall network with its associated proteins. Cell wall differentiation was also seen at the septum of dividing cells. Here, two high-density zones were sandwiched between three low-density zones. It appeared that the septum consisted of an extension of the IWZ and OWZ from the outside peripheral wall, plus a low-density middle zone that separated adjacent septal cross walls, which could contribute to cell separation during division.
Publication
Journal: Philosophical Transactions of the Royal Society B: Biological Sciences
February/26/2003
Abstract
High-resolution three-dimensional structures are now available for four of seven non-homologous fish and insect antifreeze proteins (AFPs). For each of these structures, the ice-binding site of the AFP has been defined by site-directed mutagenesis, and ice etching has indicated that the ice surface is bound by the AFP. A comparison of these extremely diverse ice-binding proteins shows that they have the following attributes in common. The binding sites are relatively flat and engage a substantial proportion of the protein's surface area in ice binding. They are also somewhat hydrophobic -- more so than that portion of the protein exposed to the solvent. Surface-surface complementarity appears to be the key to tight binding in which the contribution of hydrogen bonding seems to be secondary to van der Waals contacts.
Publication
Journal: American Journal of Tropical Medicine and Hygiene
October/24/1978
Abstract
The establishment of new strains of Plasmodium falciparum in continuous culture is described. One line (FCR-2), isolated from an individual who had traveled extensively through South America, was passed initially through Aotus trivirgatus monkeys and then cultured into human erythrocytes using the flow-vial technique. A strain of P. falciparum FMG), shipped by air freight on wet ice from The Gambia, was cultured directly from a human infection into continuous culture using the Petri dish-candle jar technique, giving line FCR-3. Two other strains (6252 and FSG) were hand carried by a commercial flight on wet ice from the Gambia and were initiated into culture at the same time using the same media, sera, and erythrocytes. After 6 wk in vitro the 6252 strain became adapted as line FCR-4, whereas FSG had died out. Normal-looking gametocytes were seen in all four strains reported here. Notwithstanding their normal appearance they would not exflagellate in vitro, nor were they infective to Anopheles stephensi mosquitoes via membrane feeding. Production of new gametocytes continued for 6 mo, then gradually stopped.
Publication
Journal: Journal of Bacteriology
November/12/1992
Abstract
A new class of cold shock-induced proteins that may be involved in an adaptive process required for cell viability at low temperatures or may function as antifreeze proteins in Escherichia coli and Saccharomyces cerevisiae has been identified. We purified a small Bacillus subtilis cold shock protein (CspB) and determined its amino-terminal sequence. By using mixed degenerate oligonucleotides, the corresponding gene (cspB) was cloned on two overlapping fragments of 5 and 6 kb. The gene encodes an acidic 67-amino-acid protein (pI 4.31) with a predicted molecular mass of 7,365 Da. Nucleotide and deduced amino acid sequence comparisons revealed 61% identity to the major cold shock protein of E. coli and 43% identity to a family of eukaryotic DNA binding proteins. Northern RNA blot and primer extension studies indicated the presence of one cspB transcript that was initiated 119 bp upstream of the initiation codon and was found to be induced severalfold when exponentially growing B. subtilis cell cultures were transferred from 37 degrees C to 10 degrees C. Consistent with this cold shock induction of cspB mRNA, a six- to eightfold induction of a cspB-directed beta-galactosidase synthesis was observed upon downshift in temperature. To investigate the function of CspB, we inactivated the cold shock protein by replacing the cspB gene in the B. subtilis chromosome with a cat-interrupted copy (cspB::cat) by marker replacement recombination. The viability of cells of this mutant strain, GW1, at freezing temperatures was strongly affected. However, the effect of having no CspB in GW1 could be slightly compensated for when cells were preincubated at 10 degrees C before freezing. These results indicate that CspB belongs to a new type of stress-inducible proteins that might be able to protect B. subtilis cells from damage caused by ice crystal formation during freezing.
Publication
Journal: Blood
June/9/1999
Abstract
Interferon gamma (IFNgamma) induces apoptosis in purified human erythroid colony-forming cells (ECFC) and inhibits cell growth. Fas (APO-1; CD95) and Fas ligand (FasL) mediate apoptosis induced by IFNgamma, because Fas is significantly upregulated by IFNgamma, whereas Fas ligand is constitutively present in the ECFC and neutralization of FasL greatly reduces the apoptosis. Because conversion of caspases from their dormant proenzyme forms to active enzymes has a critical role in transducing a cascade leading to apoptosis, we performed further studies of the expression and activation of caspases in normal human and IFNgamma-treated day-6 ECFC to better understand the mechanism of IFNgamma action in producing this cell death. RNase protection assays showed that the caspase-1, -2, -6, -8, and -9 mRNAs were upregulated by IFNgamma, whereas the caspase-5 and -7 mRNAs were not increased. Western blots showed that FLICE/caspase-8 was upregulated and activated by 24 hours of incubation with IFNgamma. FADD was not similarly altered by incubation with IFNgamma. Western blots of ICE/caspase-1, which might be required for amplification of the initial FLICE activation signal, showed that pro-ICE expression significantly increased after treatment with IFNgamma for 24 hours and cleavage of pro-ICE also increased. CPP32/apopain/caspase-3, responsible for the proteolytic cleavage of poly (ADP) ribose polymerase (PARP), was also studied and treatment of ECFC with IFNgamma resulted in an increased concentration of caspase-3 by 24 hours and a clear induction of enzyme activation by 48 hours, which was identified by the appearance of its p17-kD peptide fragment. The cleavage of PARP was demonstrated by an obvious increase of the 89-kD PARP cleavage product, which was observed at almost the same time as caspase-3 activation in the IFNgamma-treated cells, whereas untreated ECFC showed little change. Peptide inhibitors of the caspase proteins, DEVD-fmk, DEVD-cho, YVAD-cho, and IETD-fmk, were incubated with the ECFC to obtain further evidence for the involvement of caspases in IFNgamma-induced apoptosis. The activation of FLICE/caspase-8 and CPP32/caspase-3 and cleavage of PARP clearly were inhibited, but the reduction of cell growth due to apoptosis, induced by IFNgamma, was only partially blocked by the presence of the inhibitors. These results indicate that IFNgamma acts on ECFC not only to upregulate Fas, but also to selectively upregulate caspases-1, -3, and -8, which are activated and produce apoptosis, whereas the concentrations of FasL and FADD are not demonstrably changed.
Publication
Journal: BMJ (Clinical research ed.)
January/21/1996
Abstract
OBJECTIVE
To determine the acute injury profile in each of six sports and compare the injury rates between the sports.
METHODS
Analysis of national sports injury insurance registry data.
METHODS
Finland during 1987-91.
METHODS
621,691 person years of exposure among participants in soccer, ice hockey, volleyball, basketball, judo, or karate.
METHODS
Acute sports injuries requiring medical treatment and reported to the insurance company on structured forms by the patients and their doctors.
RESULTS
54,186 sports injuries were recorded. Injury rates were low in athletes aged under 15, while 20-24 year olds had the highest rates. Differences in injury rates between the sports were minor in this adult age group. Overall injury rates were higher in sports entailing more frequent and powerful body contact. Each sport had a specific injury profile. Fractures and dental injuries were most common in ice hockey and karate and least frequent in volleyball. Knee injuries were the most common cause of permanent disability.
CONCLUSIONS
Based on the defined injury profiles in the different sports it is recommended that sports specific preventive measures should be employed to decrease the number of violent contacts between athletes, including improved game rules supported by careful refereeing. To prevent dental injuries the wearing of mouth guards should be encouraged, especially in ice hockey, karate, and basketball.
Publication
Journal: ILAR Journal
May/2/2001
Abstract
Biological metabolism in living cells dramatically diminishes at low temperatures, a fact that permits the long-term preservation of living cells and tissues for either scientific research or many medical and industrial applications (e.g., blood transfusion, bone marrow transplantation, artificial insemination, in vitro fertilization, food storage). However, there is an apparent contradiction between the concept of preservation and experimental findings that living cells can be damaged by the cryopreservation process itself. The challenge to cells during freezing is not their ability to endure storage at very low temperatures (less than -180 degrees C); rather, it is the lethality of an intermediate zone of temperature (-15 to -60 degrees C) that a cell must traverse twice--once during cooling and once during warming. Cryobiological research studies the underlying physical and biological factors affecting survival of cells at low temperatures (during the cooling and warming processes). These factors and mechanisms (or hypotheses) of cryoinjury and its prevention are reviewed and discussed, including the most famous two-factor hypothesis theory of Peter Mazur, concepts of cold shock, vitrification, cryoprotective agens (CPAs), lethal intracellular ice formation, osmotic injury during the addition/removal of CPAs and during the cooling/warming process, as well as modeling/methods in the cryobiological research.
Publication
Journal: Annual Review of Physiology
May/26/1997
Abstract
The majority of ovarian follicles undergo atresia, a hormonally controlled apoptotic process. Monitoring apoptotic DNA fragmentation provides a quantitative and sensitive endpoint to study the hormonal regulation of atresia in ovarian follicles. During follicle development, gonadotropins, together with local ovarian growth factors (IGF-I, EGF/TGF-alpha, basic FGF) and cytokine (interleukin-1 beta), as well as estrogens, activate different intracellular pathways to rescue follicles from apoptotic demise. In contrast, TNF-alpha, Fas ligand, presumably acting through receptors with a death domain, and androgens are atretogenic factors. These diverse hormonal signals probably converge on selective intracellular pathways (including genes of the bcl-2 and ICE families) to regulate apoptosis. With a constant loss of follicles from the original stockpile, the ovary provides a unique model for studying the hormonal regulation of apoptosis.
Publication
Journal: American Journal of Clinical Nutrition
August/11/2016
Abstract
BACKGROUND
A growing number of cohort studies suggest a potential role of dairy consumption in type 2 diabetes (T2D) prevention. The strength of this association and the amount of dairy needed is not clear.
OBJECTIVE
We performed a meta-analysis to quantify the associations of incident T2D with dairy foods at different levels of intake.
METHODS
A systematic literature search of the PubMed, Scopus, and Embase databases (from inception to 14 April 2015) was supplemented by hand searches of reference lists and correspondence with authors of prior studies. Included were prospective cohort studies that examined the association between dairy and incident T2D in healthy adults. Data were extracted with the use of a predefined protocol, with double data-entry and study quality assessments. Random-effects meta-analyses with summarized dose-response data were performed for total, low-fat, and high-fat dairy, (types of) milk, (types of) fermented dairy, cream, ice cream, and sherbet. Nonlinear associations were investigated, with data modeled with the use of spline knots and visualized via spaghetti plots.
RESULTS
The analysis included 22 cohort studies comprised of 579,832 individuals and 43,118 T2D cases. Total dairy was inversely associated with T2D risk (RR: 0.97 per 200-g/d increment; 95% CI: 0.95, 1.00;P= 0.04;I(2)= 66%), with a suggestive but similar linear inverse association noted for low-fat dairy (RR: 0.96 per 200 g/d; 95% CI: 0.92, 1.00;P= 0.072;I(2)= 68%). Nonlinear inverse associations were found for yogurt intake (at 80 g/d, RR: 0.86 compared with 0 g/d; 95% CI: 0.83, 0.90;P< 0.001;I(2)= 73%) and ice cream intake (at ∼10 g/d, RR: 0.81; 95% CI: 0.78, 0.85;P< 0.001;I(2)= 86%), but no added incremental benefits were found at a higher intake. Other dairy types were not associated with T2D risk.
CONCLUSIONS
This dose-response meta-analysis of observational studies suggests a possible role for dairy foods, particularly yogurt, in the prevention of T2D. Results should be considered in the context of the observed heterogeneity.
Publication
Journal: Science
March/13/2013
Abstract
Surface temperature reconstructions of the past 1500 years suggest that recent warming is unprecedented in that time. Here we provide a broader perspective by reconstructing regional and global temperature anomalies for the past 11,300 years from 73 globally distributed records. Early Holocene (10,000 to 5000 years ago) warmth is followed by ~0.7°C cooling through the middle to late Holocene (<5000 years ago), culminating in the coolest temperatures of the Holocene during the Little Ice Age, about 200 years ago. This cooling is largely associated with ~2°C change in the North Atlantic. Current global temperatures of the past decade have not yet exceeded peak interglacial values but are warmer than during ~75% of the Holocene temperature history. Intergovernmental Panel on Climate Change model projections for 2100 exceed the full distribution of Holocene temperature under all plausible greenhouse gas emission scenarios.
Publication
Journal: Critical Care
March/25/2008
Abstract
BACKGROUND
Temperature management is used with increased frequency as a tool to mitigate neurological injury. Although frequently used, little is known about the optimal cooling methods for inducing and maintaining controlled normo- and hypothermia in the intensive care unit (ICU). In this study we compared the efficacy of several commercially available cooling devices for temperature management in ICU patients with various types of neurological injury.
METHODS
Fifty adult ICU patients with an indication for controlled mild hypothermia or strict normothermia were prospectively enrolled. Ten patients in each group were assigned in consecutive order to conventional cooling (that is, rapid infusion of 30 ml/kg cold fluids, ice and/or coldpacks), cooling with water circulating blankets, air circulating blankets, water circulating gel-coated pads and an intravascular heat exchange system. In all patients the speed of cooling (expressed as degrees C/h) was measured. After the target temperature was reached, we measured the percentage of time the patient's temperature was 0.2 degrees C below or above the target range. Rates of temperature decline over time were analyzed with one-way analysis of variance. Differences between groups were analyzed with one-way analysis of variance, with Bonferroni correction for multiple comparisons. A p < 0.05 was considered statistically significant.
RESULTS
Temperature decline was significantly higher with the water-circulating blankets (1.33 +/- 0.63 degrees C/h), gel-pads (1.04 +/- 0.14 degrees C/h) and intravascular cooling (1.46 +/- 0.42 degrees C/h) compared to conventional cooling (0.31 +/- 0.23 degrees C/h) and the air-circulating blankets (0.18 +/- 0.2 degrees C/h) (p < 0.01). After the target temperature was reached, the intravascular cooling device was 11.2 +/- 18.7% of the time out of range, which was significantly less compared to all other methods.
CONCLUSIONS
Cooling with water-circulating blankets, gel-pads and intravascular cooling is more efficient compared to conventional cooling and air-circulating blankets. The intravascular cooling system is most reliable to maintain a stable temperature.
Publication
Journal: Nature
December/22/1988
Abstract
The nicotinic acetylcholine receptor belongs to a class of molecules that respond transiently to chemical stimuli by opening a water-filled channel through the cell membrane for cations to diffuse. This channel lies along the central axis delineated by a ring of five homologous, membrane-spanning subunits and thus has properties, such as conductance and ion selectivity, which depend on the profile created by the encircling subunits. Insight has been gained recently about the amino-acid residues implicated directly in the ion transport, and some information about the subunit configuration around the channel has come from electron microscopy studies of postsynaptic membranes crystallized in the form of flattened tubular vesicles. The resolution along the axis of the channel has, however, been limited by the restricted range of views obtainable. Here we report the structure of the channel at 17 A resolution, determined by three-dimensional image reconstruction from tubular vesicles having receptors organized in helical arrays across their surfaces. The helical symmetry is preserved by suspending the tubes in thin films of ice, and the receptors in such tubes can be seen from all angles, allowing the channel to be revealed clearly in relation to the lipid bilayer and the peripheral protein for the first time.
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