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Thermotolerance induced by fractionated hyperthermia: dependence of the interval between fractions.

The induction of thermotolerance by fractionated hyperthermia was investigated in the mouse ear. Ears were heated at 43.5 degrees C by immersion in water. One to ten treatments of 20 min were followed by test treatments. Thermotolerance was assessed as the increase in the duration of the test treatment required for a thermal response in 50 per cent of the ears (NT50). A single treatment induced thermotolerance which reached a maximum at 24 h when the NT50 was increased by a factor of 2.4. The same maximum was observed after each fractionated treatment used in the present study. The time course of development, however, depended on the interval between fractions. (1) When the interval was too short to allow development of thermotolerance after a single fraction (4 h), thermotolerance was not induced during fractionated treatment but it developed during the first 24 h after treatment. (2) When the interval between fractions allowed the maximal development of thermotolerance (24 h), this maximum was maintained during fractionated treatment and persisted for 24 h after treatment. (3) When the interval allowed some decay of thermotolerance (72 or 168 h) there was a further increase to maximal thermotolerance after each fraction. The decay of thermotolerance from the maximum did not depend on the interval between fractions. These results indicate that the degree of thermotolerance may fluctuate during fractionated hyperthermia.

Adaptation, Physiological↗
PubMed2004

Changes in the effect of dose fractionation during daily fractionated irradiation: studies in mouse oral mucosa.

PURPOSE: The aim of the present study was to quantify the fractionation effect in mouse oral mucosa during a daily fractionated protocol. METHODS AND MATERIALS: Irradiation of the snout of C3H mice was performed with 5 x 3 Gy/week. In the first experiment, graded test doses were applied to the lower tongue on Days 4, 7, 11, 14, or 18. Subsequently, a split-dose experiment was performed on the same days with 1, 2, 3, or 5 fractions (graded doses). RESULTS: The ED50 (dose expected to induce ulcer in 50% of the mice) for untreated mucosa was 10.7 +/- 1.0 Gy. Fractionated irradiation with 5 x 3 Gy/week yielded an ED50 for top-up irradiation of 6.5 +/- 1.8 Gy, 6.8 +/- 0.9 Gy, 5.3 +/- 2.1 Gy, 7.3 +/- 1.9 Gy, and 7.5 +/- 1.3 Gy on Days 4, 7, 11, 14, and 18. The ED50 values for split-dose irradiation on Day 4 increased from 6.24 +/- 1.48 Gy (1 fraction) to 9.96 +/- 1.47 Gy (5 fractions). Similarly, an increase from 4.04 +/- 1.56 Gy to 10.07 +/- 1.9 Gy was found on Day 11, and from 5.84 +/- 2.37 Gy to 9.81 +/- 2.29 Gy on Day 18. After the weekend breaks, values between 6.22 +/- 1.60 Gy (1 fraction) and 4.7 +/- 1.95 Gy (5 fractions) were observed on Day 7, and between 5.62 +/- 1.36 Gy and 5.98 +/- 2.01 Gy on Day 14. CONCLUSIONS: These results indicate that the fractionation effect in oral mucosa is consistently lost over the weekends and restored during the treatment weeks.

Animals↗
PubMed1988

Large-scale fractionation of S-form lipopolysaccharide from Salmonella abortus equi. Chemical and serological characterization of the fractions.

The S-form lipopolysaccharide of Salmonella abortus equi was separated by a newly elaborated extraction method with organic solvents into three fractions of different chain length of the O-polysaccharide they contained. The three fractions were designated long-chain (20-50 repeating units), short-chain (0-6) and R-fraction (no repeating units) according to their migration pattern in polyacrylamide gel electrophoresis in the presence of sodium dodecylsulphate. The nature of the fractions as long- and short-chain and as R-fraction was confirmed by chemical analysis. The concentration of O-specific sugars was highest in the long-chain fraction, where their molar ratio to glucosamine was ca. 25:1. In the short-chain fraction the ratio of O-sugars to glucosamine was 2.5:1, and in the R-fraction O-specific sugars were absent. The serological properties of the three fractions were in good agreement with their chemical composition.

Carbohydrates↗
PubMed2005

Fractional systems and fractional Bogoliubov hierarchy equations.

We consider the fractional generalizations of the phase volume, volume element, and Poisson brackets. These generalizations lead us to the fractional analog of the phase space. We consider systems on this fractional phase space and fractional analogs of the Hamilton equations. The fractional generalization of the average value is suggested. The fractional analogs of the Bogoliubov hierarchy equations are derived from the fractional Liouville equation. We define the fractional reduced distribution functions. The fractional analogs of the Vlasov equation and the Debye radius are considered.

Journal Article↗
PubMed1977

Antigens of the subcellular fractions of Trypanosoma cruzi. II. Flagellar and membrane fraction.

A method for isolation of membrane and flagellar fractions from Trypanosoma cruzi epimastigotes, and descriptions of their ultrastructural characteristics and antigenic activity are presented. Electron-microscopic observation revealed that the membrane fraction resembled vesicles, as occurs frequently when the pressure-depressure method is used for cell disruption. The flagellar fraction revealed flagella and some membranes, both related and unrelated to the flagellar structure. Flagellar and membrane fractions had 5 and 3 precipitin lines respectively against anti-whole homogenate of T. cruzi, in double diffusion tests. One of the precipitin bands common to both fractions gave a reaction of identiy with one precipitin line of the microsomal fractions, that was not present in the mitochondrial, nuclear and cell sap fractions. Data from tests of protective activity activity obtained during a period of 3 years with whole homogenate and F and M fraction are also presented Protective activity against lethal challenge doses of trypomastigotes is strongly associated with the flagellar fraction.

Animals↗
PubMed1980

Test of equal effect per fraction and estimation of initial clonogen number in microcolony assays of survival after fractionated irradiation.

In the use of multifraction microcolony assays to infer the low-dose response of in situ renewal systems such as intestinal crypts, the assumption of equal effect per dose fraction is required. Moreover, the construction of a cell-survival curve requires knowledge of the initial count of cells capable of repopulating each renewal structure. We describe a method of designing fractionation protocols which provides a regression estimate of the initial number of clonogens per renewal structure and a test of the hypothesis of equal effect per fraction. The essential factor in the experimental design is the use of common dose fractions (use of the same dose per fraction in series with different numbers of fractions). Applications of the method to data for which the assumption of equal effect per fraction holds (four-hour fractionation interval testis study) and does not hold (one-hour fractionation interval jejunal crypt study) are presented.

Animals↗
PubMed2001

In addition to the high-density lipoprotein fraction, apolipoprotein C-III is detected in chylomicrons and the very low-density lipoprotein fraction from serum of normolipidemic cows.

Apolipoprotein (apo) C-III is a low-molecular-mass protein that is involved in the regulation of the triglyceride metabolism. Except for the hyperlipidemic calf, cattle apoC-III is mainly detected in the high-density lipoprotein (HDL) fraction, and the distribution in chylomicrons (CM) and the very low-density lipoprotein (VLDL) fraction has not yet been clarified. The purpose of the present study was to detect apoC-III in concentrated CM and VLDL fractions to examine whether apoC-III is distributed in the two fractions even in normolipidemic cattle. ApoC-III could be detected by immunoblot analysis in both concentrated cow CM and VLDL fractions, but not in the corresponding calf fractions. These results suggest that apoC-III is distributed in the CM and VLDL fractions, at least in cows, although the concentrations in these fractions are considerably lower than in the HDL fraction.

Animals↗
PubMed2004

Distributions of major-to-ultratrace elements among the particulate and dissolved fractions in natural water as studied by ICP-AES and ICP-MS after sequential fractionation.

In order to elucidate the distributions of the elements among the particulate and dissolved fractions in pond water, major-to-ultratrace elements in different sizes of particles as well as in the filtrate passed through the 0.05 microm filter were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). The different sizes of particle samples (ca. 100-300 microg each) were collected on the membrane filters with pore sizes of 10, 3.0, 1.2, 0.4, 0.2 and 0.05 microm, respectively, by sequential fractionation. As a result, about 40 elements in different sizes of particles could be determined by ICP-AES and ICP-MS, after acid digestion using HNO3/HF/HClO4. Then, the fractional distribution factors of major-to-ultratrace elements among the particulate and dissolved fractions were estimated from the analytical results. The total contents of Al, Fe, Ti, REEs (rare earth elements), Bi, Pb and Ag in the particulate fractions (larger than 0.05 microm) were more than 80-90%, while those of Ca, Sr, Cs, W, Ba, Mn and Co in the dissolved fraction, which corresponded to the filtrate passed through the 0.05 microm membrane filter, were more than 80%. It was further found that the fractional distributions of Cu and Zn in the dissolved fraction were ca. 50%. In addition, the enrichment factors (EFs) of the elements in the particulate fractions with particle sizes of 3.0-10 microm and 0.05-0.2 microm were estimated to elucidate their geochemical characteristics in natural water.

Journal Article↗
PubMed1982

Fractionation and quantitation of egg antigens from Schistosoma japonicum by the single-tube kinetic-dependent enzyme-linked immunosorbent assay (k-ELISA): higher antigenic activity in urea-soluble than in aqueous-soluble fractions.

To identify sources of high potency antigens for use in serodiagnosis, aqueous-soluble egg antigens from Schistosoma japonicum were extracted with Dulbecco's phosphate-buffered saline. Residual particulates were solubilized with Tris-buffered 8 M urea, yielding a urea-soluble egg antigen fraction. The urea-soluble fraction was further fractionated with Bio Gel A50m and QAE-Sephadex. All fractions were quantitatively assayed for their specific antigenic activities against serum specimens from infected rabbits by the single-tube enzyme-linked immunosorbent assay (k-ELISA). In antigen rate-limiting conditions, the urea-soluble particulate fractions were more antigenically active than the aqueous-soluble fraction. In antigen-excess and antibody-limiting assay conditions, the ideal conditions for serologic assays, the urea-derived antigens also showed superior activities against sera from infected humans. Analysis by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) on gradient gels revealed numerous low molecular weight protein bands in the aqueous-soluble fraction, whereas the urea-soluble fractions appeared to be much simpler with the majority of their proteins concentrated in one or two high molecular weight bands (greater than or equal to 200 kdaltons). Electro-transfer blots of the SDS-PAGE onto nitrocellulose papers and subsequent visualization of antigens by enzyme-linked immunoabsorbence confirmed these findings. The above data suggest that the urea-soluble fraction of S. japonicum eggs is antigenically active and has potential use in the development of a diagnostic reagent.

Animals↗
PubMed1994

[The effect of the time interval between fractions on the result of a fractionated irradiation of the R1H tumor].

BACKGROUND: The response of an experimental tumor to hyperfractionated irradiation with different time intervals between the two daily fractions has been investigated. MATERIAL AND METHODS: Tumors were exposed to irradiation five days per week over six weeks. A standard treatment of 30 fractions, i.e. one fraction per day (200 kVp X-rays) was compared with a hyperfractionated schedule of 60 fractions, i.e. two fractions per day, with time intervals of either one, two, three, five or six hours between the two daily fractions. RESULTS: Compared with standard treatment a significant reduction (p < 0.005) of net growth delay was observed for the tumors treated with two daily fractions separated by two hours. However, at a time interval of five and six hours between the two daily fractions net growth delay increased considerably (p < 0.0001 and p < 0.01) as compared with the standard treatment. CONCLUSION: Our results indicate the importance of the time interval between the daily fractions in hyperfractionated and accelerated radiotherapy.

Animals↗
PubMed1961

Serum fractionation and the effects of bovine serum fractions on human cells grown in a chemically defined medium.

Serum has been fractionated by curtain electrophoresis using carboxymethyl cellulose dissolved in sodium bicarbonate electrolyte. Various fractions were produced from bovine serum and added to replicate cultures of Chang's endoepithelial cells and HeLa cells grown in a chemically defined medium. The effects of each of the various fractions on the appearance of the cultures and on cell multiplication were studied. Three different fractions were obtained and two were subjected to further purification. One fraction associated with albumin promoted survival, attachment, and flattening as well as cell multiplication. A second fraction associated with the alpha globulins promoted survival and multiplication of some cells. A third fraction caused cells to aggregate and form free floating clumps. An adequate chemically defined medium for continuous growth of human cells was used throughout the study. The response of cells to alterations in their environment which simulated some of the effects produced by serum fractions is described.

Animals↗
PubMed2005

Natural sample fractionation by FlFFF-MALLS-TEM: sample stabilization, preparation, pre-concentration and fractionation.

Two flow field flow fractionation (FlFFF) systems: symmetrical (SFlFFF) and asymmetrical (ASFlFFF) were evaluated to fractionate river colloids. Samples stability during storage and colloids concentration are the main challenges limiting their fractionation and characterization by FlFFF. A pre-fractionation (<0.45 microm) and addition of a bactericide such as NaN3 into river colloidal samples allowed obtaining stable samples without inducing any modification to their size. Stirred cell ultra-filtration allowed colloidal concentration enrichment of 25-folds. Scanning electron microscope (SEM) micrographs confirmed the gentle pre-concentration of river samples using the ultra-filtration stirred cell. Additionally, larger sample injection volume in the case of SFlFFF and on channel concentration in the case of ASFlFFF were applied to minimize the required pre-concentration. Multi angle laser light scattering (MALLS), and transmission electron microscope (TEM) techniques are used to evaluate FlFFF fractionation behavior and the possible artifacts during fractionation process. This study demonstrates that, FlFFF-MALLS-TEM coupling is a valuable method to fractionate and characterize colloids. Results prove an ideal fractionation behavior in case of Brugeilles sample and steric effect influencing the elution mode in case of Cézerat and Chatillon. Furthermore, comparison of SFlFFF and ASFlFFF fractograms for the same sample shows small differences in particle size distributions.

Colloids↗
PubMed2004

Hepatoprotective and antioxidant effects of Bupleurum kaoi Liu (Chao et Chuang) extract and its fractions fractionated using supercritical CO(2) on CCl(4)-induced liver damage.

Fractionation with supercritical CO(2) is employed to divide ethanolic extract (E) of B. kaoi into four fractions (R, F1, F2 and F3). To assess the selectivity of the fractionation, extracts of the four fractions were characterized in terms of the hepatoprotective capacity and activity of antioxidant enzymes to against CCl(4)-induced damage. The in vitro study revealed that pretreatment with B. kaoi extract or its fractions, except F3, significantly protected primary hepatocytes against damage by CCl(4) (P<0.05). The R and F1 fractions had the highest saikosaponins content (175 and 200 mg/g dry weight, respectively) and most effectively protected the liver from damage by CCl(4). This study demonstrated that the oral pretreatment of B. kaoi (100 and 500 mg/kg), except F3, three days before a single dose of CCl(4) (CCl(4)/olive oil=1:1, 3 ml/kg, sc) was administered significantly lowered the serum levels of hepatic enzyme markers (AST and ALT) (P<0.05). A pathological examination showed that lesions, including ballooning degeneration, necrosis, hepatitis and portal triaditis were partially healed by treatment with B. kaoi extract and fractions. Oxidative stress induced by CCl(4) led to lipid peroxidation (MDA) and changes in the levels of the antioxidant enzymes in the liver. However, all the fractions, except F3, markedly suppressed lipid peroxidation and reversed the activities of the antioxidant enzymes to the normal levels.

Administration, Oral↗
PubMed1999

Literature analysis of high dose rate brachytherapy fractionation schedules in the treatment of cervical cancer: is there an optimal fractionation schedule?

PURPOSE: A literature review and analysis was performed to determine whether or not efficacious high dose rate (HDR) brachytherapy fractionation schedules exist for the treatment of cervical cancer. METHODS AND MATERIALS: English language publications from peer reviewed journals were assessed to calculate the total contribution of dose to Point A from both the external and intracavitary portions of radiation for each stage of cervical cancer. Using the linear quadratic formula, the biologically effective dose to the tumor, using an alpha/beta = 10, was calculated to Point A (Gy10) in order to determine a dose response relationship for local control and survival. Significant complications were assessed by calculating the dose to the late-responding tissues at Point A using an alpha/beta = 3 (Gy3) as a surrogate for normal tissue tolerance, since few publications list the actual bladder and rectal doses. RESULTS: For all stages combined, the median external beam fractionation schedule to Point A was 40 Gy in 20 fractions, while the median HDR fractionation schedule was 28 Gy in 4 fractions. For stages IB, IIB, and IIIB the median biologically effective dose to Point A (Gy10) was 96, 96 and 100 Gy10s, respectively. No correlation was identified between Point A BED (Gy10s) to either survival or pelvic control. A dose response relationship could also not be identified when correlating Point A Gy3s to complications. CONCLUSION: A dose response relationship could not be identified for either tumor control nor late tissue complications. These findings do not necessarily question the validity of the linear quadratic model, as much as they question the quality of the current HDR brachytherapy literature as it is currently presented and reported. Most of the HDR publications report inadequate details of the dose fractionation schedules. Only a minority of publications report significant complications using the actuarial method. In the future, all HDR publications for the treatment of cervical cancer should provide accurate fractionation details for each stage of disease, while reporting actuarial complication rates. The optimal fractionation schedule for treating cervical cancer using HDR brachytherapy is still unknown, and presently can be based only on single institutions with significant experience.

Brachytherapy↗
PubMed1977

Two fractions of rough endoplasmic reticulum from rat liver. II. Cytoplasmic messenger RNA's which code for albumin and mitochondrial proteins are distributed differently between the two fractions.

Subcellular fractions were obtained from rat liver homogenates under conditions which prevented degradation of polysomes (pH 8.5 and high ionic strength). Rough endoplasmic reticulum (RER) was recovered in high yields from a low-speed nuclear pellet (rapidly sedimenting endoplasmic reticulum, RSER) and from a postmitochondrial supernate (rough microsomes). The polysomal RNA content of these two fractions was very similar. When polyA+-RNA's were translated inthe mRNA-dependent wheat embryo cell-free system, both fractions yielded polypeptide products which had similar electrophoretic patterns on sodium dodecyl sulfate (SDS)-polyacrylamide gels. Activities of messenger RNA's which code for albumin and for polypeptides destined for transport to the inner membrane and matrix of mitochondria (i.e. 'mitoplasts') were assayed by translating in the more active rabbit reticulocyte cell-free system followed by immunoprecipitation of radioactive products and coelectrophoresis with immunoprecipitated marker proteins on SDS-polyacrylamide gels. These tests indicated that albumin mRNA is about equally distributed between the two fractions of RER, or slightly enriched in the RSER fraction when activity is expressed as a percentage of total polypeptide synthesis. Activities of cytoplasmic mRNA's which code for at least some mitoplast proteins could be detected in both fractions, but all were enriched in the rough microsome fraction, not the RSER (two- to threefold when corrected for differences in total polypeptide synthesis in the lysate). Comparisons of mRNA's from free vs. membrane-bound polysomes indicated that most of the albumin mRNA activity (86-91%) and mitoplast protein mRNA activities (75%) were present in the bound fraction. Assuming that RSER and rough microsomes do not derive exclusively from different cells types, the evidence suggests that, compared to albumin and most other membrane-bound mRNA's, cytoplasmic mRNA's coding for mitoplast proteins may be preferentially segregated or compartmentalized within the cell on the microsomal class of RER.

Albumins↗
PubMed1988

Subcellular fractionation of the porcine corpus luteum: sequestration of progesterone in a unique particulate fraction.

Homogenates of porcine corpus luteum were subjected to fractionation by differential-rate centrifugation or sucrose density gradient fractionation, with or without pretreatment with digitonin. Fractions of each gradient were assayed for a number of markers characteristic of the major intracellular organelles and cell-surface membranes, and for progesterone content. The majority of the progesterone content of homogenates of porcine corpus luteum was associated with a low-density particulate fraction which equilibrated at a buoyant density of 1.07-1.09 g/cm3. Pretreatment with digitonin increased the buoyant density of the progesterone-enriched fraction markedly (to 1.13-1.15 g/cm3) without causing release of steroid. The density distributions of progesterone content in control and digitonin-treated luteal gradient fractions were quite distinct from those of the major intracellular organelles and luteal cell-surface membranes. However, NADH-cytochrome C reductase activity (but not other endoplasmic reticulum markers) was also enriched in this fraction. The results suggest that most of the progesterone of the porcine corpus luteum is associated with a unique particulate fraction which is enriched in digitonin-reactive lipids and NADH-cytochrome C reductase activity.

Animals↗
PubMed2005

Production and characterisation of two wheat-bran fractions: an aleurone-rich and a pericarp-rich fraction.

Wheat bran is a good source of dietary fibre in the form of cell walls, but contains a number of different cell types. We describe a large-scale procedure for the production of an aleurone-rich and a pericarp-rich fraction from hard, Australian wheat. The fractions were characterised by field-emission scanning electron microscopy, by using a range of bright-field stains, colour reagents, and fluorochromes, and by chemical analysis of the walls. The aleurone fraction included the seed coat with its cuticle. Only the pericarp walls showed a histochemical reaction for lignin. The concentrations of ester-linked ferulic acid and (1-->3),(1-->4)-beta-glucans were greater in the aleurone-rich fraction than in the pericarp-rich fraction. The results are consistent with the arabinoxylans in the walls of the pericarp-rich fraction being more highly substituted with arabinose than those in the walls of the aleurone-rich fraction. When the fractions were fed as a dietary supplement to rats and walls were isolated from the faeces, it was found that the pericarp walls were not degraded, but the aleurone walls were partially degraded.

Animals↗