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At least 361 records · Page 20Linked to original sources
PubMed1996

Iced temperature injectate for thermodilution cardiac output determination causes minimal effects on cardiodynamics.

OBJECTIVES: Controversy exists regarding the ideal injectate temperature for measuring cardiac output. Iced temperature injectate gives a higher signal/noise ratio and less variability in the measured cardiac output. Thus, less volume and fewer measurements are required. Advocates of room temperature injectate have suggested that iced temperature injectate may perturb cardiodynamics. This concern has remained largely untested. To help resolve this controversy, we examined the effects of 5 mL iced injectate (0 degrees to 4 degrees) infusions on cardiodynamics. DESIGN: Prospective, randomized, controlled study. SETTING: A critical care research laboratory. SUBJECTS: Five domestic pigs, weighing between 20 to 25 kg. INTERVENTIONS: Under barbiturate anesthesia, pigs underwent placement of a) a thermodilution catheter in the right internal jugular vein; b) a right carotid artery catheter for mean arterial pressure; and c) sonomicrometry crystals for dynamic measurements of left ventricular dimensions. Calculations were made of end-systolic and end-diastolic left ventricular volume and ejection fraction. Six cardiac output measurements were performed in each pig. Data were obtained at baseline (just before iced temperature injectate infusion) and every 3 sec for 9 secs. MEASUREMENTS AND MAIN RESULTS: The only significant effect seen with iced temperature injectate infusion was a small, transient decrease in heart rate (-5.9 +/- 1.1 beats/min from a baseline heart rate of 144.8 +/- 20.6 beats/min). Indices of preload, contractile function, and dynamic cardiac geometry were unaffected. CONCLUSIONS: Iced temperature injectate used in clinically relevant volumes causes transient negative chronotropic effects, but reservations regarding other perturbations of cardiodynamics are unfounded. Thus, the use of iced temperature injectate for cardiac output determination is still a viable alternative to room temperature injectate use, especially when a larger signal/noise ratio is required.

Analysis of Variance↗
PubMed2001

Do textbooks agree on their advice on ice?

OBJECTIVE: To study ice therapy guidance in sports medicine textbooks. DATA SOURCES: A systematic search of a convenience sample of textbooks. STUDY SELECTION: 45 general sports medicine texts were included in the study. DATA EXTRACTION: The indices and chapter headings of each text were searched using key words "ice," "cryotherapy," "soft tissue injury," "muscle," and "bruise." DATA SYNTHESIS: In 17 of the textbooks, there was no guidance on the duration, frequency, or length of ice treatment or on the use of barriers between ice and the skin. Advice on treatment duration was given in 28 texts but recommendations differed depending on the particular ice therapy, injury location, or severity. There was considerable variation in the recommended duration and frequency of advised treatments. CONCLUSION: There was little guidance in the standard textbooks on ice application, and the advice varied greatly. There is a need for evidence-based sport and exercise medicine with a consensus on the appropriate use of ice in acute soft tissue injury.

Athletic Injuries↗
PubMed2004

Pre- and post-thaw assessment of intracellular ice formation.

Intracellular ice formation (IIF) refers to the formation of ice crystals within cells during rapid freezing. To develop an understanding of the means by which intracellular ice forms and the mechanisms by which it damages cells and tissues requires techniques that combine real-time assessment of ice nucleation and ice crystal growth with detailed assessments of cell structure and function. Intracellular ice formation has been detected in live samples using light scattering, freeze substitution and fluorescent detection. In this study we develop a method to correlate IIF with post-thaw structural analyses by combining low temperature microscopy and freeze substitution. V79-4 hamster fibroblasts were frozen on a low temperature microscope at various temperatures, IIF was visualized using the nucleic acid-specific fluorophore SYTO 13, then the samples were fixed (10% formaldehyde, 85% ethanol, 5% acetic acid) while still frozen. The monolayers were then thawed and stained with routine histological stains haematoxylin and eosin and assessed. Fixation allowed for the post-thaw assessment of IIF and for subsequent histological processing to examine in detail the structural consequences of IIF. The post-thaw identification of cells that form intracellular ice during freezing is a significant improvement to current methods used in low temperature biology.

Animals↗
PubMed1992

Oxygen supersaturation in ice-covered Antarctic lakes: biological versus physical contributions.

Freezing in ice-covered lakes causes dissolved gases to become supersaturated while at the same time removing gases trapped in the ablating ice cover. Analysis of N2, O2, and Ar in bubbles from Lake Hoare ice shows that, while O2 is approximately 2.4 times supersaturated in the water below the ice, only 11% of the O2 input to this lake is due to biological activity: 89% of the O2 is derived from meltwater inflow. Trapped bubbles in a subliming ice cover provide a natural "fluxmeter" for gas exchange: in Lake Hoare as much as 70% of the total gas loss may occur by advection through the ice cover, including approximately 75% of the N2, approximately 59% of the O2, and approximately 57% of the Ar losses. The remaining gas fractions are removed by respiration at the lower boundary (O2) and by molecular exchange with the atmosphere in the peripheral summer moat around the ice.

Antarctic Regions↗
PubMed1985

Cloning and expression of bacterial ice nucleation genes in Escherichia coli.

Epiphytic populations of Pseudomonas syringae and Erwinia herbicola are important sources of ice nuclei that incite frost damage in agricultural crop plants. We have cloned and characterized DNA segments carrying the genes (ice) responsible for the ice-nucleating ability of these bacteria. The ice region spanned 3.5 to 4.0 kilobases and was continuous over this region in P. syringae Cit7R1. The cloned fragments imparted ice-nucleating activity in Escherichia coli. Substantial increases in the nucleating activity of both E. coli and P. syringae were obtained by subcloning the DNA fragments on multicopy plasmid vectors. Southern blot analysis showed substantial homology between the ice regions of P. syringae and E. herbicola, although individual restriction sites within the ice regions differed between the two species.

Chromosome Mapping↗
PubMed1991

Components of ice nucleation structures of bacteria.

Nonprotein components attached to the known protein product of the inaZ gene of Pseudomonas syringae have been identified and shown to be necessary for the most efficient ice nucleation of supercooled H2O. Previous studies have shown that cultures of Ina+ bacteria have cells with three major classes of ice-nucleating structures with readily differentiated activities. Further, some cells in the culture have nucleating activities intermediate between those of the different classes and presumably have structures that are biosynthetic intermediates between those of the different classes. Since these structures cannot be readily isolated and analyzed, their components have been identified by the use of specific enzymes or chemical probes, by direct incorporation of labeled precursors, and by stimulation of the formation of specific classes of freezing structures by selective additions to the growth medium. From these preliminary studies it appears that the most active ice nucleation structure (class A) contains the ice nucleation protein linked to phosphatidylinositol and mannose, probably as a complex mannan, and possibly glucosamine. These nonprotein components are characteristic of those used to anchor external proteins to cell membranes of eucaryotic cells and suggest that a similar but not identical anchoring mechanism is required for efficient ice nucleation structure. The class B structure has been found to contain protein presumably linked to the mannan and glucosamine moieties but definitely not to the phosphatidylinositol. The class C structure, which has the poorest ice nucleation activity, appears to be the ice nucleation protein linked to a few mannose residues and to be partially imbedded in the outer cell membrane.

Bacterial Outer Membrane Proteins↗
PubMedDate not supplied

The effects of ice on blood flow and bone metabolism in knees.

The effects of an ice wrap, applied to a knee for 20 minutes, on blood flow and bone metabolism were measured using triple-phase technetium bone scans. Twenty-one subjects between 29 and 63 years of age were studied. A commercially available ice wrap was applied to one knee 20 minutes before scanning, while an identical wrap left at room temperature was applied to the opposite knee to act as a control. Scans of the knees were obtained at the completion of cooling, and the images were quantified by computer image analysis for each knee at each phase of the scan. Percentage of decrease in blood flow and subsequent bone uptake of technetium for the iced knee as compared with the opposite knee were calculated. All iced knees demonstrated decreased arterial and soft tissue blood flow as well as decreased bone uptake, which is a reflection of changes in both bone blood flow and metabolism. The average decrease was 38.4% +/- 4.97 in arterial blood flow, 25.8% +/- 2.04 in soft tissue blood flow, and 19.3% +/- 2.0 (standard error of the mean in each) in bone uptake. This "ice effect" was not related to age, sex, knee circumference, or skin temperature after cooling. By decreasing blood flow and cell metabolism, ice theoretically can limit hemorrhage and cell death in the setting of acute traumatic injury. This study thus provides a scientific rationale for the use of ice as tested for such injuries to a large joint, whether in the soft tissues or bones.

Adult↗
PubMed1998

Soil hydric characteristics and environmental ice nuclei influence supercooling capacity of hatchling painted turtles Chrysemys picta.

Hatchling painted turtles (Chrysemys picta) hibernate in their shallow natal nests where temperatures occasionally fall below -10 C during cold winters. Because the thermal limit of freeze tolerance in this species is approximately -4 C, hatchlings rely on supercooling to survive exposure to extreme cold. We investigated the influence of environmental ice nuclei on susceptibility to inoculative freezing in hatchling C. picta indigenous to the Sandhills of west-central Nebraska. In the absence of external ice nuclei, hatchlings cooled to -14.6 1.9 C (mean s.e.m.; N=5) before spontaneously freezing. Supercooling capacity varied markedly among turtles cooled in physical contact with sandy soil collected from nesting locales or samples of the native soil to which water-binding agents (clay or peat) had been added, despite the fact that all substrata contained the same amount of moisture (7.5 % moisture, w/w). The temperature of crystallization (Tc) of turtles exposed to frozen native soil was -1.6 0.4 C (N=5), whereas turtles exposed to frozen soil/clay and soil/peat mixtures supercooled extensively (mean Tc values approximately -13 C). Hatchlings cooled in contact with drier (less than or equal to 4 % moisture) native soil also supercooled extensively. Thus, inoculative freezing is promoted by exposure to sandy soils containing abundant moisture and little clay or organic matter. Soil collected at turtle nesting locales in mid and late winter contained variable amounts of moisture (4-15 % w/w) and organic matter (1-3 % w/w). In addition to ice, the soil at turtle nesting locales may harbor inorganic and organic ice nuclei that may also seed the freezing of hatchlings. Bulk samples of native soil, which were autoclaved to destroy any organic nuclei, nucleated aqueous solutions at approximately -7 C (Tc range -6.1 to -8.2 C). Non-autoclaved samples contained water-extractable, presumably organic, ice nuclei (Tc range -4.4 to -5.3 C). Ice nuclei of both classes varied in potency among turtle nesting locales. Interaction with ice nuclei in the winter microenvironment determines whether hatchling C. picta remain supercooled or freeze and may ultimately account for differential mortality in nests at a given locale and for variation in winter survival rates among populations.

Animals↗
PubMedDate not supplied

Studies on the effects of ice collars on nasal blood volume using optical rhinometry.

BACKGROUND: The possible benefit of ice collars for treatment of nosebleed is controversial. The aim of this study was to investigate changes of nasal blood volume before and after application of ice collars to the neck. Nasal blood volume was investigated using optical rhinometry. METHODS: A total of 15 young, healthy volunteers participated. After ice collars were placed on the neck area of the subjects, changes in the blood volume of the nose were measured by means of optical rhinometry for the whole nose, but also regionally at the nasal septum (Kiesselbach's area). After baseline measurements over 1 minute, the ice collar was applied. Optical rhinometric measurements were performed continuously. RESULTS: Although the ice collar showed no effect on the blood volume of the whole nose, there was a significant decrease in blood volume (p < 0.01) at the septum. CONCLUSION: Application of ice collars to the neck area of the subjects is followed by a decrease in blood volume of Kiesselbach's area, which may provide the basis for the clinical observation that ice collars are helpful in the treatment of nosebleeds.

Adult↗
PubMed1992

Survival of Lactobacillus acidophilus and Bifidobacterium bifidum in ice cream for use as a probiotic food.

Probiotic ice cream was made by fermenting a standard ice cream mix with Lactobacillus acidophilus and Bifidobacterium bifidum cultures and then freezing the mix in a batch freezer. Survival of the L. acidophilus and B. bifidum, as well as beta-galactosidase activity, was monitored during 17 wk of frozen storage at -29 degrees C. After freezing of the fermented mix, bacterial counts were 1.5 x 10(8) cfu/ml for L. acidophilus and 2.5 x 10(8) cfu/ml for B. bifidum. Seventeen weeks after freezing, these counts had decreased to 4 x 10(6) and 1 x 10(7) cfu/ml, respectively. During the same period, beta-galactosidase activity decreased from 1800 to 1300 units/ml. Probiotic ice cream was prepared at pH 5.0, 5.5, and 6.0 to determine consumer preferences and was compared with standard Utah State University "Aggie" ice cream. All samples were strawberry-flavored and were evaluated by 88 judges. The preferred pH of probiotic ice cream, based on overall acceptance, was pH 5.5. We demonstrated that probiotic ice cream is a suitable vehicle for delivering beneficial microorganisms such as L. acidophilus and B. bifidum to consumers. The bacteria can be grown to high numbers in ice cream mix and remain viable during frozen storage.

Animals↗
PubMed2000

Interstitial ice formation in cryopreserved homografts: a possible cause of tissue deterioration and calcification in vivo.

BACKGROUND AND AIM OF THE STUDY: Cryopreserved valve homografts often fail in infants. Controversies are ongoing concerning the relative contributions of cryopreservation variables, immune responses, cellular viability, and durability of the extracellular matrix to the mode of tissue failure. METHODS: Tissues to be examined for patterns of ice crystal distribution were cryopreserved. Tissue water was substituted with methanol and the tissues cryopreserved conventionally using dimethylsulfoxide, after which they were warmed and processed for light or electron microscopy. Selected specimens were vitrified to prevent ice crystal formation, cryopreserved, and subsequently warmed and processed for light and electron microscopy. RESULTS: Cryosubstitution of conventionally cryopreserved heart valves, while still frozen, demonstrated extensive extracellular ice formation, with smaller crystals in the ventricularis than in either the spongiosa or fibrosa. Extracellular ice formation was prevented by vitrification, a process in which the biological system is stabilized as an amorphous solid in the absence of crystalline ice. CONCLUSION: It is proposed that the extensive ice formation observed in conventionally cryopreserved heart valves may cause extracellular matrix damage that predisposes the valves to calcification. Future studies will assess the above hypothesis by comparison of conventional and ice-free (vitrification) cryopreservation methods in animal models of calcification.

Animals↗
PubMed2002

Local ice therapy during bouts of acute gouty arthritis.

OBJECTIVE: To evaluate the effect of local application of ice on duration and severity of acute gouty arthritis. METHODS: Nineteen patients with acute gout were enrolled and randomized into 2 groups. Group A (n = 10) received topical ice therapy, oral prednisone 30 mg PO tapered to 0 over 6 days and colchicine 0.6 mg/day. Group B was the control group (n = 9), given the same regimen but without the ice therapy. The patients were followed for one week. RESULTS: The mean reduction in pain for those patients treated with ice therapy was 7.75 cm (on 10 cm visual analog scale) with standard deviation +/- 2.58 compared with 4.42 cm (+/- SD 2.96) for the control group. Using a Wilcoxon rank-sum test there was a significant difference (p = 0.021 ) in pain reduction between the ice therapy and control groups. Joint circumference and synovial fluid volume also tended to be more effectively reduced after one week of therapy in the ice group compared with controls, but these did not achieve statistical significance. CONCLUSION: The group treated with ice had a significantly greater reduction in pain compared with the control group. Although the clinical improvement was impressive, due to the small sample size we could not show statistically significant improvement in all the variables that tended to suggest that effect was more than simply analgesic. Cold applications may be a useful adjunct to treatment of acute gouty arthritis.

Arthritis, Gouty↗
PubMedDate not supplied

Ice can penetrate invertebrate tissues via paracellular pathways.

Ice-cell interactions especially the question whether and how ice crystals invade tissues and organs during freezing were examined in small transparent organs (salivary glands) in which many structural details remained visible despite of freeze-induced cell darkening. In most glands no invasion of ice into the lumen was observed since ice dendrites stopped growing after touching the gland. Here I report that in rare cases a so far unknown type of ice crystals developed which aggressively pushed against cell membranes before invading the gland via paracellular pathways (septate junctions). Aggressive ice crystals were also observed within a salivary gland cell which deformed and finally invaded the nucleus. In cell strands it was observed that intracellular freezing is indeed a two-step event in which ice developed in cytoplasm several seconds before invading the nucleus.

Animals↗
PubMedDate not supplied

[A comparative analysis of the ice nucleation activity of pseudomonad cells and lipopolysaccharides].

The paper deals with the study of the ice nucleation activity of the cells, extracellular lipopolysaccharides (ELPSs), lipopolysaccharides (LPSs), and their structural components (lipid A, core oligosaccharide, and O-specific polysaccharide) of Pseudomonas fluorescens, P. syringae, P.fragi, and P. pseudoalcaligenes. The aqueous suspensions of the intact cells of P. syringae IMV 1951 and IMV 185 began to freeze at -1 and -4 degrees C, respectively. This suggests that these cells possess ice nucleation activity. The aqueous cell suspensions of two other strains, P. fluorescens IMV 1433 and IMV 2125, began to freeze at lower temperatures than did distilled water (-9 degrees C), which suggests that the cells of these strains possess antifreeze activity. The ice nucleation activity of the bacterial strains studied did not show any correlation with their taxonomic status. The ice nucleation activity of ELPSs depended little on their concentration (within a concentration range of 0.2-0.4%). In most cases, the ice nucleation activity of ELPSs, LPSs, and their structural components differed from that of the intact cells from which these biopolymers were obtained. This may indicate that the biopolymers under study play a role in ice nucleation, but this role is not crucial. The relationship between the structure of LPSs and their effect on ice nucleation is discussed.

Freezing↗
PubMed2006

[Phylogenetic diversity and cold-adaptive hydrolytic enzymes of culturable psychrophilic bacteria associated with sea ice from high latitude ocean, Artic].

The phylogenetic diversity of culturable psychrophilic bacteria associated with sea ice from high latitude sea (77 degrees 30'N - 81 degrees 12'N), Canadian Basin and Greenland sea Arctic, was investigated. A total of 37 psychrophilic strains were isolated using three different methods of ( i ) spread plate method: 100 microL of each dilution ice-melt sample was spreaded onto the surface of Marine 2216 agar (DIFCO laboratories, Detroit, MI) and incubated for 2 to 6 weeks at 4 degrees C; ( ii ) bath culture and spread plate method: 1 mL of sample was added to 9mL of NSW (unamended natural seawater, 0.2 microm prefiltered and autoclaved) and incubated for 1 months at - 1 degrees C, then spread plate method was used to isolate bacterial strains from the pre-cultured samples; ( iii ) cold shock, bath culture and spread plate method: samples were exposed to - 20 degrees C for 24h, then bacterial strains isolated by bath culture and spread plate method under aerobic conditions. Nearly half of psychrophilic strains are isolated by using method iii . 16S rDNA nearly full-length sequence analysis reveal that psychrophilic strains fall in two phylogenetic divisions, gamma-proteobacteria (in the genera Colwellia, Marinobacter, Shewanella, Thalassomonas, Glaciecola, Marinomonas and Pseudoalteromonas) and Cytophaga-Flexibacter-Bacteroides (in the genera Flavobacterium and Psychroflexus). Nine of bacterial isolates (BSi20007, BSi20497, BSi20517, BSi20537, BSi20170, BSi20001, BSi20002, BSi20675 and BSi20101) quite likely represent novel species (16S rDNA sequence similarity below 97%). One of strains (BSi20002) from Canadian Basin shows 100% sequence similarity to the Antarctic Weddell sea ice isolate Marinobacter sp. ANT8277, suggesting bacteria may have a bipolar distribution at the species level. AF283859 sequences were submitted to the BLAST search program of the National Center for Biotechnology Information website (NCBI, http://www. ncbi. nlm.nih. gov). Twenty sequences showing 100% similarity each other are retrieved from the database, eleven from Antarctic seawater bacteria, three from Antarctic sea-ice bacteria, one from Spitzbergen sea-ice bacteria, two from Chukchi Sea sea-ice bacteria, two from Canadian Basin sea-ice bacteria (in this study) and one from uncultured bacterium clone PDA-OTU11 associated with the coral Pocillopora damicornis from the Great Barrier Reef. These may indicate that the physiological and geographic barriers appear to be permeable and some bacterial species can survive in different environment. The majority of the bacterial strains are able to secrete diversity cold-adaptive hydrolytic enzymes into the medium at 4 degrees C. The isolates that are able to degrade Tween-80, glutin, and starch account for, respectively, 62.6%, 51.4% and 40.5%.

Arctic Regions↗
PubMed1989

Structure-function relationship in a winter flounder antifreeze polypeptide. II. Alteration of the component growth rates of ice by synthetic antifreeze polypeptides.

Using synthetic analogs of an alpha-helical winter flounder antifreeze polypeptide (AFP) we investigated some important molecular details of the mechanism of action of this AFP. Of the seven peptides synthesized, all but one were amino-terminal deletions of the native AFP. Three of the seven synthetic analogs possessed the same antifreeze activity as the native polypeptide; the other analogs were devoid of antifreeze activity. The growth rates along the a and c axes of ice in solutions of varying concentrations of the three active AFP analogs were examined. The a axis growth rates of ice were inversely proportional to the concentration of the active peptides. The c-axis growth rates of ice were also dependent on peptide concentration. The active peptides enhanced c-axis growth at lower concentrations, while at higher concentrations they inhibited c axis growth. The ability of the peptides to develop antifreeze activity and to alter the a and c axis growth rates of ice depended on the presence of appropriately positioned amino acid residues with hydrogen bonding side chains. From these observations we propose that at low concentrations the AFP, through dipolar interactions and hydrogen bonding, interact with the prism faces of ice retarding a axis growth. At these concentrations, the electrical field of the AFP helix-dipole, like an externally applied field (Bartlett, J.T., van der Heuval, A.P., and Mason, B.J. (1963) Z. Angew. Math. Phys. 14, 599-610), can enhance ice c axis growth. At higher concentrations, the AFP interact with all ice crystal planes and retard both a and c axis growth.

Animals↗
PubMed1983

The effects of exercise, ice, and ultrasonography on torsional laxity of the knee.

Changes in torsional knee laxity, after subjects ran 3.5 miles during a 30-minute period, were studied in 13 subjects. The effects of ice and ultrasonographic treatments on these laxity changes were then investigated. Knee laxity was determined by measuring torque versus rotation responses of the tibia at 90 degrees of knee flexion. Total rotational laxity of the tibia was tabulated at +/- 10 newton-meters of applied torque. There were significant increases in postexercise laxities over preexercise levels for internal and external tibial rotation. Postexercise laxity changes followed a uniform time course of recovery. The maximum postexercise laxity represented a mean increase of 14% over pre-exercise levels, with a mean recovery time of 52.4 minutes and a standard deviation of 17.8 minutes. The application of ten-minute treatments of either ice or ultrasonography significantly reduced postexercise recovery times, to 20.0 +/- 4.6 SD and 20.9 +/- 6.4 SD, respectively. A common clinical assumption, that cold and heat have opposite effects on knee laxity, was found invalid. In the authors' study, ice and ultrasonography had equivalent effects in accelerating the return to pre-exercise laxities. No laxity changes were observed in unexercised subjects, with either ice or ultrasonographic treatments. The time course of laxity recovery and the subsequent effects of heat and ice are important clinically. Immediately after injury, both knees are more lax than normal, and after approximately one hour, recovery to pre-exercise laxity levels will be complete for the uninjured leg. Ice (or ultrasonography) will shorten this time to 20 minutes. If these recovery time courses are recognized and taken into account, a more accurate diagnosis can be made during this "golden opportunity" period before pain and swelling ensue. The fact that ice and ultrasonography have identical effects on the time course of recovery in the exercised knee raises new questions and suggests additional areas for future work in the recently developing field of sports medicine biomechanics.

Adult↗
PubMed1997

Sequential operation of ceramide synthesis and ICE cascade in CPT-11-initiated apoptotic death signaling.

The chemotherapeutic agent CPT-11 induced apoptotic cell death in mouse fibroblast 4B1 cells. To examine the intracellular apoptotic death signal initiated by CPT-11, ceramide synthesis and the ICE cascade were analyzed. CPT-11-initiated cytolytic activity was prevented by both caspase inhibitors YVAD-CHO and DEVD-CHO, or ceramide synthesis inhibitor fumonisin B1, and accelerated by sphingomyelin, suggesting the direct involvement of ceramide synthesis and the interleukin 1-beta converting enzyme (ICE) cascade. In addition, apoptosis was induced by both native and synthesized ceramide and prevented by YVAD-CHO and DEVD-CHO, suggesting the possible involvement of ceramide in ICE cascade operation. To directly demonstrate whether ceramide synthesis operates the ICE cascade, proteolytic activity of ICE- or CPP32-like proteinase was analyzed. ICE-like proteinase activity was prevented by fumonisin B1 and YVAD-CHO, but not by DEVD-CHO. In contrast, fumonisin B1, YVAD-CHO, and DEVD-CHO all prevented CPP32-like proteinase activity. These results suggest that ceramide synthesis acts as a dominant regulator in CPT-11-initiated death signaling and sequentially operates the ICE cascade.

Animals↗