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PubMed2001

Characteristics of different molecular weight fractions of organic matter in landfill leachate and their role in soil sorption of heavy metals.

We have characterised two kinds of municipal landfill leachates derived from 'old' and 'young' municipal waste landfills on the basis of the molecular weight distribution of the constituents, taking into account that the great variety of leachate constituents prevents any evaluation of the fate and of the role played by each component in the environmental impact. In the sample S1 (old leachate), the constituents were distributed over a wider range of molecular weights; high molecular weight fractions were present. In sample S2 (young leachate), the fractions are actually narrower at the lower molecular weights. The high molecular weight fractions of old leachates are found to be complex structures formed by condensed nuclei of carbons substituted by functional groups containing nitrogen, sulphur and oxygen atoms; the low molecular weight fractions of leachates are, instead, characterised by linear chains substituted by oxygenated functional groups such as carboxyl and/or alcoholic groups. After characterising each fraction we studied the role played by these fractions in the soil's capability for retaining heavy metals [copper (Cu) and cadmium(Cd)]. The Cd uptake increases only on the soil treated with sample S1 characterised by a higher pH value and by the presence of high molecular weight fractions. The Cu uptake also increases on the soil treated with sample S2, characterised by the sole presence of low molecular weight fractions. On the other hand, the metal adsorption tests performed on soil treated with the single fractions show that the amount of Cu and Cd retained by soil treated with the high molecular weight fractions of sample does not increase after 72 h of treatment and that the amount of Cu retained by the low molecular weight fractions of sample S1 and by the fractions of sample S2 increases, but does not justify the amount retained by soil treated with the total leachates.

Adsorption↗

PubMed1991

Factors determining improvement in left ventricular function after reperfusion therapy for acute myocardial infarction: primacy of baseline ejection fraction.

Improvement in left ventricular ejection fraction is a measure of salvage of ischemic myocardium after reperfusion therapy for acute myocardial infarction. The degree of improvement in left ventricular ejection fraction may be influenced by many factors. Therefore, 137 patients in whom paired radionuclide angiograms were obtained within 24 h of acute infarction and before hospital discharge were retrospectively evaluated to determine which factors most affect improvement in ejection fraction. Only baseline ejection fraction correlated significantly with improvement in ejection fraction by both univariate analysis (ejection fraction as a continuous variable; p less than 0.001; ejection fraction as a categorical variable, less than or equal to 45% versus greater than 45%, p less than 0.0001) and multivariate analysis (p less than 0.0001). Reperfusion status (patent versus occluded infarct artery) and extent of coronary artery disease (one, two or three vessel) were significant factors by multivariate but not by univariate analysis. Location of infarction, treatment modality and time to treatment did not correlate with change in ejection fraction by either statistical technique. Thus, of those factors tested, baseline left ventricular ejection fraction is the most potent predictor of improvement in ventricular function after acute infarction. Knowledge of baseline ejection fraction may be helpful in deciding whether to treat some patients with equivocal indications or contraindications for reperfusion therapy. Clinical trials of reperfusion strategies should stratify patients on the basis of baseline ejection fraction if ejection fraction is to be used as an end point for myocardial salvage.

Adult↗

PubMed1984

Mechanism and significance of a decrease in ejection fraction during exercise in patients with coronary artery disease and left ventricular dysfunction at rest.

The purpose of this study was to determine whether an exercise-induced decrease in ejection fraction in patients with coronary artery disease and left ventricular dysfunction at rest represents ischemia or the nonspecific response of a compromised left ventricle to exercise stress. Accordingly, radionuclide ejection fraction responses of 246 patients with coronary artery disease and an ejection fraction at rest of less than 0.50 were compared with those of a "nonischemic" control group of 48 patients with idiopathic dilated cardiomyopathy and a similar degree of ventricular dysfunction. The significance of the ejection fraction response in the group with coronary artery disease was further examined by relating it to the angiographic extent of coronary artery disease, severity of angina, incidence of chest pain and electrocardiographic ST segment depression during exercise and long-term prognosis. The ejection fraction decreased by greater than or equal to 0.01 and greater than or equal to 0.05 during exercise in 48 and 28%, respectively, of the patients with coronary artery disease compared with only 8 and 2%, respectively, of the patients with cardiomyopathy. When exercise was limited by fatigue at a submaximal heart rate, the ejection fraction decreased in 25% of the patients with coronary artery disease but in none of the patients with cardiomyopathy. Patients with coronary artery disease whose ejection fraction decreased during exercise had a significantly higher incidence of three vessel disease, exercise-induced chest pain or ST depression and late mortality than did patients whose ejection fraction did not decrease. These relations were confirmed equally in subgroups of patients with moderate (ejection fraction 0.30 to 0.49) and severe (ejection fraction less than 0.30) left ventricular dysfunction. Thus, in patients with coronary artery disease and left ventricular dysfunction at rest, a decrease in ejection fraction during exercise is more likely to indicate ischemia than a nonspecific left ventricular response to exercise stress. In the individual patient, a decrease of 0.05 or greater, or a decrease during submaximal exercise, appears to be highly specific for ischemia. A decrease in ejection fraction identifies a subgroup of patients with a high prevalence of multivessel coronary artery disease and a high risk of death during long-term follow-up on medical therapy.

Adult↗

PubMed1996

Amrinone stimulation test: ability to predict improvement in left ventricular ejection fraction after coronary bypass surgery in patients with poor baseline left ventricular function.

OBJECTIVES: This study sought to determine whether the response to amrinone in patients with severe baseline left ventricular dysfunction can predict improvement in left ventricular ejection fraction after coronary artery bypass graft surgery. BACKGROUND: Previous studies have suggested that the inotropic response to dobutamine can identify viable myocardium in the setting of chronic coronary disease and left ventricular dysfunction. However, increased oxygen demand stimulated by dobutamine can lead to superimposition of ischemia on the hibernating state, potentially confounding interpretation of results. Amrinone is an inotropic agent that does not critically augment myocardial oxygen demand and may be useful for identification of hibernating myocardium in the chronically ischemic state. METHODS: Forty-four consecutive patients with coronary artery disease and left ventricular ejection fraction < 40% referred for coronary artery bypass graft surgery underwent amrinone stimulation (1 mg/kg body weight). Left ventricular ejection fraction was determined before amrinone stimulation, 20 min after infusion and 21 days after bypass surgery. RESULTS: Baseline ejection fraction was 28 +/- 7% (mean +/- SD). Ejection fraction increased to 35 +/- 5% after amrinone stimulation (p < 0.0001) and to 33 +/- 6% after bypass surgery (p < 0.0001). Postbypass ejection fraction was significantly correlated with postamrinone ejection fraction (r = 0.65, p < 0.0001). Furthermore, the change in ejection fraction from baseline to after bypass surgery was highly correlated with the change in ejection fraction after amrinone stimulation (r = 0.75, p < 0.0001). Of 13 patients with an increase in ejection fraction > or = 10% after amrinone, all 13 had an increase of at least 8% and 11 (85%) of 13 had an increase > or = 10% after bypass surgery. In contrast, of 31 patients with an increase in ejection fraction < 10% after amrinone, only 2 (6%) had an increase > or = 10% (p < 0.0001) and 28 (90%) of 31 had an increase < 5% after bypass surgery. CONCLUSIONS: Augmentation of myocardial contraction by amrinone in patients with chronic coronary artery disease and severe baseline left ventricular dysfunction predicts improvement in left ventricular ejection fraction after coronary artery bypass graft surgery.

Aged↗

PubMed1993

Multiple fractions daily for head and neck cancer: spinal cord effects and other late results.

Reports of late spinal cord damage after multiple fractions daily radiotherapy regimens for head and neck cancer are infrequent, but increasing. We have reviewed our experience of head and neck cancers treated thrice daily to examine this problem. Between 1982 and 1990, 65 patients with advanced head and neck cancer were treated by primary radiotherapy using three small fractions delivered on 5 days per week, with an inter-fraction interval of 3-4 hours during normal working hours. In 25 patients, the cervical spinal cord received > 39 Gy. In 13 patients, 39.6 Gy was given in 1.1 Gy fractions, and five received 41.8 Gy in 1.1 Gy fractions, two received 45.1 Gy in 1.1 Gy fractions and five received 45 Gy in 1.5 Gy fractions. Eleven of these patients have survived over 2 years, and can be assessed for late spinal cord damage. Ten of these received 1.1 Gy fractions with no cord damage. The only 2-year survivor whose cord received 45 Gy in 1.5 Gy fractions has developed mild, non-progressive long tract signs. Other late side effects were equivalent to those after conventionally fractionated radiotherapy. Tumour control was good, especially for the larynx. We feel that, for radiotherapy given with three small fractions daily and an inter-fraction interval of 3-4 hours, the spinal dose should not exceed 40 Gy.

Carcinoma, Squamous Cell↗

PubMed2004

Echinococcus granulosus coproantigens: chromatographic fractionation and characterization.

Dogs infected with adult tapeworms of Echinococcus granulosus release antigens (coproantigens) in faeces which can be detected by a capture ELISA. Supernatants prepared from E. granulosus-infected dog faecal samples were fractionated by size-exclusion fast protein liquid chromatography (FPLC) on a Superose-6 column. Coproantigen ELISA and Western blotting were used to demonstrate the immunoreactivity of eluted fractions. Two main FPLC peaks of antigenic activity were detected and designated as fraction F1 and fraction F2 with approximate relative molecular weights > 670 kDa, and in the range of 146 to 440 kDa respectively. These two antigenic fractions (F1 and F2) fractionated from infected dog faeces were heat stable and largely protease-insensitive, but were highly sensitive to sodium periodate treatment, which strongly suggested the involvement of carbohydrates. Capture IgG antibodies against E. granulosus proglottis somatic extracts, detected a molecule with an approximate molecular weight of 155 kDa in fraction F2 after immunoblotting. The 155 kDa antigen could be completely ablated by sodium periodate treatment, but not after protease or lipase treatment. A surface tegument preparation of adult E. granulosus tapeworms contained large amounts of antigen that corresponded in size range and antigenicity to that observed in the FPLC fraction F2. There was also a peak of antigenic activity at > 670 kDa corresponding to fraction F1 from a culture derived excretory-secretory (E-S) adult tapeworm preparation. The involvement of carbohydrate moieties in coproantigen activity present in the FPLC fractions F1 and F2 from faecal supernatants of E. granulosus-infected dogs was confirmed by lectin-binding assays and exoglycosidase treatment, which showed that alpha-D-mannose and/or alpha-D-glucose, beta-galactose and N-acetyl-beta-glucosamine residues were the most important carbohydrate components in putative coproantigens present in both fractions. N-acetyl-beta-glucosamine and sialic acid residues were also contained in coproantigen molecules present in fraction F2. These results suggested that coproantigens detected in faeces of E. granulosus-infected dogs are large molecular weight molecules that may be derived from the carbohydrate-rich surface glycocalyx of adult worms, and are shed, released or secreted during the life-span of the tapeworm.

Animals↗

PubMed2001

Nutrient distribution and phenolic antioxidants in air-classified fractions of beach pea (Lathyrus maritimus L.).

Beach pea (Lathyrus maritimus L.) cotyledons and hulls were air-classified into different fractions. The crude protein content (%N x 6.25) of samples ranged from 32.8 to 35.3% in cotyledons and 14.7 to 16.8% in hulls. Crude fiber content was higher in hulls fraction 1 (37.13%) and fraction 2 (36.85%) than in cotyledons (2.83, 2.99, and 3.08% in fractions 1, 2, and 3, respectively). Condensed tannins of cotyledons ranged from 5.76 to 6.90% and of hulls ranged from 52.49 to 57.24%, expressed as catechin equivalents. Minerals, namely P, K, and Zn, were higher in cotyledons, but Ca and Mn were more prevalent in hulls. Nonprotein nitrogen was concentrated in hulls, whereas phytic acid was more abundant in the cotyledons. The UV absorption pattern showed that flavonoids were present in fractions (I-III) from hulls separated on Sephadex LH-20. Fraction III from hulls had the highest content of total phenolics and condensed tannins, but no condensed tannins were detected in fractions I and II from hulls. The antioxidant activity of fractions separated on Sephadex LH-20 from hulls and crude extracts in a beta-carotene-linoleate model system was in the order of fraction III > crude extract > fraction II > fraction I. Spots on silica gel TLC plates, sprayed with a solution of beta-carotene and linoleic acid, indicated that many of the individual compounds were antioxidative in nature. Further, separation of fraction III from hulls on a semipreparative HPLC showed the presence of (+) catechin and (-) epicatechin as the main low-molecular-weight phenolic compounds present.

Antioxidants↗

PubMed1984

Chemopotentiation in vivo: no loss of sensitization with fractionation.

The response of KHT sarcomas to one, two, five or ten daily fractions of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), with and without misonidazole (MISO), was evaluated using delay of tumour regrowth as the measure of response. When CCNU was given as 2 dose fractions separated by 24 h rather than as a single treatment, no extra dose was necessary to achieve a particular level of damage, suggesting a lack of damage repair. With increasing fraction number, however, an increasing total dose of drug was required to achieve a given effect, presumably to compensate for proliferation. Increasing drug doses also were readily tolerated (almost twice the LD50/7 for a single dose of CCNU resulted in no deaths when given in a 10 fraction treatment) indicating a large sparing of normal tissue toxicity when CCNU treatments were fractionated. The addition of MISO enhanced the tumour response to CCNU in all treatment schemes. When single doses of CCNU were combined with 0.5 mg g-1 MISO, an enhancement ratio (ER) of approximately 1.5 was observed. This ER was maintained for all fractionated treatment schedules including the 10 daily fraction protocol. In addition, no loss of sensitization with increasing fractionation was observed when a lower dose of 0.2 mg g-1 MISO was combined with each of 5 or 10 daily fractions of CCNU. Similar experiments were performed to test the combination of cyclophosphamide (Cy) and MISO (0.5 mg g-1) in the RIF-1 tumour; again chemopotentiation was maintained with increasing fractionation. These results of combined MISO and fractionated chemotherapy are in contrast to the rapid loss of sensitization observed when MISO is used as a radiation sensitizer and combined with small doses of X-rays, thus providing in vivo evidence of the mechanistic difference between the effects of MISO used as a radiation sensitizer or chemopotentiator. Peripheral white blood cell counts performed on mice receiving 5 daily fractions of CCNU +/- MISO displayed no significant enhancement of normal tissue toxicity by MISO. Thus combining MISO with repeated low dose treatments of a chemotherapeutic agent results in a therapeutic gain.

Animals↗

PubMed1970

Heterogeneity of rat liver mitochondrial fractions and the effect of tri-iodothyronine on their protein turnover.

1. Rat liver mitochondria were separated into heavy, light and fluffy fractions by differential centrifugation under standard conditions. 2. All mitochondrial fractions possessed soluble as well as membrane-bound enzymes typical of mitochondria. 3. The heavy fraction represented the stable mitochondrial structures and the fluffy particles appear to be loosely coupled. 4. The light mitochondrial fraction lacked the ability of coupled phosphorylation. 5. A study of mobility and isoelectric pH indicated a similarity in the basic membrane structure of all the mitochondrial fractions. 6. The turnover rates of proteins in the heavy and fluffy particles were almost identical; however, this rate was rapid for the light mitochondrial fraction. 7. On treatment with 3,3',5-tri-iodo-l-thyronine, succinoxidase activity was maximally stimulated much earlier in the light mitochondrial fraction than in the heavy fraction. The activity of the fluffy particles, however, remained almost unaffected. 8. Malate dehydrogenase activity in all the mitochondrial fractions was stimulated only at 40h after tri-iodothyronine treatment. 9. The pattern of incorporation of dl-[1-(14)C]leucine in vivo in the tri-iodothyronine-treated animals indicated a rapid initial incorporation and high synthetic ability of the light mitochondrial fraction. 10. The turnover pattern of proteins of the mitochondrial fractions from animals receiving repeated doses of tri-iodothyronine was remarkably different from the normal pattern and suggested that preformed soluble protein units may be incorporated in the light mitochondrial fraction during maturation to form the stable heavy mitochondria. 11. The amount of light-mitochondrial proteins decreased by 40% on thyroidectomy and increased by 160% on treatment with tri-iodothyronine. 12. The possible significance of these results is discussed in relation to mitochondrial genesis.

Adenosine Triphosphatases↗

PubMed2006

Trends in prevalence and outcome of heart failure with preserved ejection fraction.

BACKGROUND: The prevalence of heart failure with preserved ejection fraction may be changing as a result of changes in population demographics and in the prevalence and treatment of risk factors for heart failure. Changes in the prevalence of heart failure with preserved ejection fraction may contribute to changes in the natural history of heart failure. We performed a study to define secular trends in the prevalence of heart failure with preserved ejection fraction among patients at a single institution over a 15-year period. METHODS: We studied all consecutive patients hospitalized with decompensated heart failure at Mayo Clinic Hospitals in Olmsted County, Minnesota, from 1987 through 2001. We classified patients as having either preserved or reduced ejection fraction. The patients were also classified as community patients (Olmsted County residents) or referral patients. Secular trends in the type of heart failure, associated cardiovascular disease, and survival were defined. RESULTS: A total of 6076 patients with heart failure were discharged over the 15-year period; data on ejection fraction were available for 4596 of these patients (76 percent). Of these, 53 percent had a reduced ejection fraction and 47 percent had a preserved ejection fraction. The proportion of patients with the diagnosis of heart failure with preserved ejection fraction increased over time and was significantly higher among community patients than among referral patients (55 percent vs. 45 percent). The prevalence rates of hypertension, atrial fibrillation, and diabetes among patients with heart failure increased significantly over time. Survival was slightly better among patients with preserved ejection fraction (adjusted hazard ratio for death, 0.96; P=0.01). Survival improved over time for those with reduced ejection fraction but not for those with preserved ejection fraction. CONCLUSIONS: The prevalence of heart failure with preserved ejection fraction increased over a 15-year period, while the rate of death from this disorder remained unchanged. These trends underscore the importance of this growing public health problem.

Aged↗

PubMed1977

Membrane fractions from the outer layers of spores of Bacillus thuringiensis with toxicity to lepidopterous larvae.

Two membrane fractions, F1 and F2, have been purified from the outer layers of spores of Bacillus thuringiensis. Both fractions contain 6-7% cysteine and appear to be similar in composition. Amino acids account for about 75% of the dry weight, carbohydrate for about 2% and lipids for about 25%. The fractions are both toxic to Pieris brassicae and the toxicity is inactivated by antiserum to the toxic crystal of Bacillus thuringiensis. The fractions can be distinguished by examination under the electron microscope; both fractions show similar hexagonal patterns but with different spacings. The same fractions from an acrystaliferous mutant (cr) were prepared. These were identical in density and in appearance under the electron microscope; the amino acid analysis of fraction F2 from both strains was identical. However, the spores and fractions F1 and F2 from this strain lacked toxicity. Fraction F2 from the cr strain was used to prepare antiserum specific to fraction F2. Using this anti-serum and anticrystal serum, crystal and F2 antigens were shown to appear simultaneously in sporulating cultures. Crystal and F2 antigens appeared some time before the maximum rate of uptake of [35s]cysteine. It is concluded that fraction F2 is derived from the exosporium and that fraction F1 probably originates from the spore coat. The exosporium in Bacillus thuringiensis appears to be synthesised during stages II and III of sporulation although uptake of [35S]cysteine occurs much later.

Amino Acids↗

PubMed1985

Characterization of myelin fractions from human brain white matter.

Myelin and myelin-containing (P3) fractions were prepared from human white matter by discontinuous sucrose gradient centrifugation. The myelin isolated from each of the fractions of different densities was morphologically and biochemically distinct. Light myelin fractions consisted of compact, multilamellar myelin, whereas the denser fractions consisted predominantly of loose myelin with fewer lamellae. The amounts of both basic protein and lipophilin (proteolipid protein) were reduced in the denser fractions. In contrast, the high-molecular-weight components were elevated in the dense fractions. The lipid composition was similar in all the fractions studied. Analysis of basic protein by gel electrophoresis at pH 10.6 revealed differences in basic protein microheterogeneity among the fractions. The light myelin fraction was enriched in the more positively charged basic protein components (components 1, 2, and 3), whereas these components were reduced in the denser fractions. Myelin in the dense fractions was enriched in the more modified forms of basic protein (components 6, 7, and 8). The pattern of microheterogeneity was different for basic protein isolated from myelins of a 2-year-old and an adult brain; the former showed fewer components and mainly the most cationic species. On the other hand, the pattern of microheterogeneity of basic protein isolated from the different density gradient fractions was similar for both ages.

Brain Chemistry↗

PubMed1986

Macrophage activation by Tetrahymena pyriformis. II. Active protein fractions from Tetrahymena.

Water-soluble and 0.6 M KCl-soluble protein fractions prepared from Tetrahymena pyriformis, when inoculated into mice, could effectively induce activated macrophages having the ability to kill Toxoplasma gondii in vitro. This effect was not induced by other proteins tested, such as bovine serum albumin, pepsin from porcine stomach mucosa and chicken egg-white lysozyme, nor by muramyl dipeptide (MDP), a potent immunoadjuvant. Five fractions obtained by DEAE-Sephadex chromatography of the water-soluble protein fraction were compared with regard to induction of toxoplasmacidal activity in macrophages. The first peak was most effective for activation of macrophages. Five fractions obtained by chromatography of the 0.6 M KCl-soluble protein fraction were also examined and it was found that the first peak had the activity. No marked difference in activity was observed between the active fractions of water-soluble and 0.6 M KCl-soluble protein fractions. For practical use, we focused on the water-soluble active fraction. The minimum effective dose of the active fraction was 100 micrograms and the fraction could activate macrophages directly in vitro. Four fractions obtained by gel filtration of the active fraction on Sephadex G-200 were compared and the first peak had the activity. The first peak contained a single protein, revealed by SDS-polyacrylamide gel electrophoresis; its apparent molecular weight was 64,000.

Animals↗

PubMed2001

Microbial population structures in soil particle size fractions of a long-term fertilizer field experiment.

Soil structure depends on the association between mineral soil particles (sand, silt, and clay) and organic matter, in which aggregates of different size and stability are formed. Although the chemistry of organic materials, total microbial biomass, and different enzyme activities in different soil particle size fractions have been well studied, little information is available on the structure of microbial populations in microhabitats. In this study, topsoil samples of different fertilizer treatments of a long-term field experiment were analyzed. Size fractions of 200 to 63 microm (fine sand fraction), 63 to 2 microm (silt fraction), and 2 to 0.1 microm (clay fraction) were obtained by a combination of low-energy sonication, wet sieving, and repeated centrifugation. Terminal restriction fragment length polymorphism analysis and cloning and sequencing of 16S rRNA genes were used to compare bacterial community structures in different particle size fractions. The microbial community structure was significantly affected by particle size, yielding higher diversity of microbes in small size fractions than in coarse size fractions. The higher biomass previously found in silt and clay fractions could be attributed to higher diversity rather than to better colonization of particular species. Low nutrient availability, protozoan grazing, and competition with fungal organisms may have been responsible for reduced diversities in larger size fractions. Furthermore, larger particle sizes were dominated by alpha-Proteobacteria, whereas high abundance and diversity of bacteria belonging to the Holophaga/Acidobacterium division were found in smaller size fractions. Although very contrasting organic amendments (green manure, animal manure, sewage sludge, and peat) were examined, our results demonstrated that the bacterial community structure was affected to a greater extent by the particle size fraction than by the kind of fertilizer applied. Therefore, our results demonstrate specific microbe-particle associations that are affected to only a small extent by external factors.

Bacteria↗

PubMed1974

Protein fraction with immunogenic potential and low toxicity isolated from the cell wall of Neisseria meningitidis group B.

Several fractions were extracted from the cell envelope (CE) of Neisseria meningitidis group B and characterized with regard to their morphology, antigenicity, protein composition, and toxicity. Whole bacterial cells were suspended in a medium of low ionic strength and disrupted in a French pressure cell. The crude CE thus obtained were separated into cell membrane (CM) enriched and cell wall (CW) enriched fractions on sucrose density gradients. In addition, CM and CW fractions were separated from CE on the basis of differential solubility in the nonionic detergent, Triton X-100. The Triton-insoluble fraction, containing primarily CW components, was further treated with a mixture of Triton and ethylenediaminetetraacetic acid, which was shown to remove additional protein and most of the lipopolysaccharide. Electron microscope examination of the various fractions revealed typical unit membrane structures in the case of CM, or large, open segments in the case of CW. The Triton-insoluble and especially the Triton-ethylenediaminetetraacetic acid-insoluble fractions consisted of small vesicular structures. All fractions, except the Triton-soluble fraction, when assayed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, were shown to contain one major protein component accounting for more than 50% of the total. Sera from rabbits immunized with the various fractions formed precipitin lines in immunodiffusion tests against the homologous and some of the heterologous fractions. High-titer bactericidal antibodies were also demonstrated in these sera when tested against the homologous strains. Toxicity studies in rats sensitized with lead acetate indicate that the level of contamination of Triton-insoluble/Triton-ethylenediaminetetraacetic acid-insoluble fractions with lipopolysaccharide was significantly smaller than that of the other fractions.

Animals↗

PubMed1965

IMMUNOGENIC ACTIVITY OF A RIBOSOMAL FRACTION OBTAINED FROM MYCOBACTERIUM TUBERCULOSIS.

Youmans, Anne S. (Northwestern University Medical School, Chicago, Ill.), and Guy P. Youmans. Immunogenic activity of a ribosomal fraction obtained from Mycobacterium tuberculosis. J. Bacteriol. 89:1291-1298. 1965.-The highly immunogenic particulate fraction obtained from mechanically ruptured cells of the H37Ra strain of Mycobacterium tuberculosis was suspended and centrifuged at 20,360 x g. The supernatant liquid from this centrifugation was centrifuged at 56,550 x g to remove the larger particles, and the supernatant liquid from this was centrifuged at 144,000 x g to obtain a ribosomal fraction. The sediments from the first two centrifugations were highly immunogenic, but the ribosomal fraction showed only slight capacity to immunize mice. However, when the ribosomal fraction was mixed with Freund's incomplete adjuvant, the immunogenic activity was equivalent to the particulate fraction from which it was prepared. To test the hypothesis that some membranous substance in the particulate fraction was acting as an adjuvant for the smaller particles in the ribosomal fraction, portions of the particulate fraction were treated separately with each of the membrane-disrupting agents, sodium deoxycholate, sodium lauryl sulfate, and 1 m sodium chloride. The treated materials were then centrifuged at 144,000 x g, and the sediments were tested for immunogenicity both with and without the addition of Freund's incomplete adjuvant. Without the adjuvant, the immunizing activities were very weak or absent; with the adjuvant, they were equivalent to that of the particulate fraction from which they were prepared. Other factors which have been found to damage or destroy membranes, such as freezing and thawing, and heat, also significantly decreased the immunogenic activity of the particulate fraction unless it was incorporated into Freund's incomplete adjuvant. The larger particles which sedimented at 56,550 x g were also treated with sodium lauryl sulfate and sodium chloride. Again, immunogenicity was greatly reduced but was fully restored by use of Freund's incomplete adjuvant. The data suggest, then, that the immunizing component of the particulate fraction is a substance (ribosomal?) which sediments at 144,000 x g, but for maximal immunizing activity a labile, possibly membranous, moiety of the mycobacterial cell, which has the properties of an adjuvant, is required.

Animals↗

PubMed1966

Isolation and characterization of fractions of Mycoplasma pneumoniae. I. Chemical and chromatographic separation.

Prescott, B. (National Institute of Allergy and Infectious Diseases, Bethesda, Md.), O. Sobeslavsky, G. Caldes, and R. M. Chanock. Isolation and characterization of fractions of Mycoplasma pneumoniae. I. Chemical and chromatographic separation. J. Bacteriol. 91:2117-2125. 1966.-Fractionation of Mycoplasma pneumoniae, cultured on a beef heart infusion-horse serum-yeast extract medium, was carried out by chemical and chromatographic procedures. The chemical method yielded eight fractions consisting of lipid, carbohydrates, and proteins. Four protein-rich fractions were isolated by chromatographing a supernatant fluid of sonically treated organisms on Sephadex G-25. The 12 fractions were tested for serological and antigenic activity in vitro and in vivo. The lipid fraction was serologically active and the relative order of activity of the protein fractions appeared to depend on the amount of lipid present in the molecule. The highly serologically active Sephadex G-25 protein fraction 1 prepared chromatographically contained 15% lipid in the molecule, whereas the less serologically active protein fraction 2 prepared by chemical means contained 2% lipid. The acetone-extracted lipid fraction was chromatographed on thin-layer chromatography plates and found to consist of nine fractions. Serological activity was associated with only the first three spots above the origin. Lipid extracted from the protein fractions seemed to be similar to the acetone-extracted lipid from the sediment of the sonically treated organisms.

Amino Acids↗

PubMed1995

Pressure and volume loading of the right ventricle have opposite effects on left ventricular ejection fraction.

BACKGROUND: Left ventricular ejection fraction has been reported to be depressed in patients with right ventricular volume overload (RVVO) due to Ebstein's anomaly and uncomplicated atrial septal defect, whereas it is usually preserved in right ventricular pressure overload (RVPO) due to congenital pulmonic stenosis. In the present study, we examined the hypothesis that the differential timing of active displacement of the ventricular septum into the left ventricle in RVPO (end systole) and RVVO (end diastole) results in opposite effects of RVPO and RVVO on left ventricular ejection fraction. METHODS AND RESULTS: Ten patients with severe tricuspid regurgitation after tricuspid valve resection for endocarditis and 10 patients with primary pulmonary hypertension were studied as models of isolated RVVO and RVPO, respectively. Left ventricular ejection fraction, end-diastolic volume, and regional systolic shortening were measured with the use of echocardiographic techniques in these 20 patients and 10 healthy control subjects. In RVPO, despite marked underfilling of the left ventricle relative to the healthy control subjects (end-diastolic volume, 48 +/- 26 versus 77 +/- 20 mL; P < .02), left ventricular ejection fraction was similar to that of the control subjects (56 +/- 5% versus 60 +/- 4%; P = .07) and only 1 of 10 RVPO patients had an ejection fraction of less than 50%. In contrast, in RVVO the left ventricle was volume replete (end-diastolic volume, 84 +/- 26 versus 77 +/- 20 mL; P = NS), but left ventricular ejection fraction was significantly depressed (51 +/- 4% versus 60 +/- 4%, P < .001) compared with the control subjects, and 4 of 10 RVVO patients had an ejection fraction of less than 50%. Analysis of systolic fractional shortening along two perpendicular short-axis diameters and the mutually orthogonal long axis demonstrated isolated augmentation of fractional shortening in the ventricular septal-to-posterolateral free wall dimension in RVPO (47.4 +/- 13.7% versus 34.2 +/- 13.1%, P < .05) and isolated depression of fractional shortening along that same dimension in RVVO (13.7 +/- 11.8% versus 34.2 +/- 13.1%, P < .001) compared with the control subjects. CONCLUSIONS: End-systolic leftward ventricular septal shift in RVPO results in isolated augmentation of systolic shortening in the septal-to-free wall dimension, whereas end-diastolic leftward ventricular septal shift in RVVO results in isolated reduction in systolic shortening in the septal-to-free wall dimension. As a result, despite relative underfilling of the left ventricle in RVPO, resting left ventricular ejection fraction is preserved, whereas ejection fraction is depressed for the volume-replete left ventricle of patients with RVVO.

Adolescent↗