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At least 1,063 records · Page 59Linked to original sources
PubMed2000

Low fractional calcium absorption increases the risk for hip fracture in women with low calcium intake. Study of Osteoporotic Fractures Research Group.

BACKGROUND: Decreased ability to absorb calcium with age limits adaptation to low calcium intake and is thought to lead to secondary hyperparathyroidism and increased risk for hip and other fractures. However, the associations between fractional calcium absorption, dietary calcium intake, and risk for fracture have never been studied. OBJECTIVE: To determine whether low fractional calcium absorption in women with low calcium intake increases the risk for subsequent hip and other nonspine fractures. DESIGN: Prospective cohort study. SETTING: Four clinical centers in Baltimore County, Maryland; Portland, Oregon; Minneapolis, Minnesota; and the Monongahela Valley, Pennsylvania. PARTICIPANTS: 5452 nonblack women 69 years of age or older participating in the fourth examination of the Study of Osteoporotic Fractures. MEASUREMENTS: Fractional calcium absorption was measured by using a 3-hour single isotope (45Ca) technique. Incident fractures were identified prospectively and were confirmed by radiographic report. RESULTS: During an average of 4.8 years, 729 women (13%) experienced at least one nonspine fracture; 153 of these women had hip fractures. After adjustment for age, women with lower fractional calcium absorption were at increased risk for hip fracture (relative risk per 1-SD [7.7%] decrease in fractional calcium absorption, 1.24 [95% CI, 1.05 to 1.48]). Women with low fractional calcium absorption and low calcium intake were at greatest risk for subsequent hip fracture; among women whose dietary calcium intake was less than 400 mg/d, those who had fractional calcium absorption at or below the median value of 32.3% had a 2.5-fold (CI, 1.29-fold to 4.69-fold) increase in risk for hip fracture compared with those who had greater absorption efficiency. Fractional calcium absorption was not related to risk for other nonspine fractures (relative risk per 1-SD [7.7%] decrease in fractional calcium absorption, 1.05 [CI, 0.96 to 1.14]). CONCLUSIONS: In elderly women, low fractional calcium absorption in the setting of low calcium intake increases the risk for hip fracture. Our findings support the hypothesis of type II osteoporosis, which postulates that decreased calcium absorption is an important risk factor for hip fracture in older persons.

Aged↗
PubMed1975

Ability of six different lipoprotein fractions to regulate the rate of hepatic cholesterogenesis in vivo.

Two in vivo assay procedures were used to study the inhibitory activity of cholesterol carried in three intestinal lymph and three serum lipoprotein fractions on the rate of cholesterol synthesis in the liver. In the first preparation, different lipoproteins were injected intravenously as a bolus into rats at the mid-light phase of the diurnal light cycle, following which they were killed 12 hours later in the mid-dark phase of the cycle. Using this assay, three intestinal lymph lipoprotein fractions of varying Sf values all produced a similar degree of inhibition which averaged approximately 11%/mg of cholesterol injected. The serum lipoprotein fractions caused only about one-third this amount of inhibition. Detailed analysis of events occurring within the liver during this 12-hour assay period revealed that there were marked differences in the rate of net cholesterol uptake into the liver and in the rate of new removal of cholesterol esters from the liver following injection of each of these different lipoprotein fractions. The amount of inhibition of sterol synthesis produced by any fraction was proportional to the product of the incremental increase in hepatic cholesterol ester content and the time over which this increase in esters occurred. In the second type of assay where the lipoprotein fractions were administered to the animals as a continuous intravenous infusion over 24 hours the largest increase in hepatic cholesterol ester content and the greatest inhibition of cholesterol synthesis was found with intestinal lipoproteins having Sf values larger than 8000. Intestinal lipoprotein fractions with lower Sf values and all serum lipoprotein fractions were significantly less effective in bringing about an increase in hepatic cholesterol ester content and in producing inhibition of cholesterol synthesis by the liver. These studies emphasize the primary role of cholesterol carried in lipoproteins of intestinal origin in regulating hepatic sterol synthesis. The inhibitory activity of these fractions appears to correlate with the ability of these lipoproteins to bring about a maximal increase in hepatic cholesterol ester content which, in turn, appears to relate to the capacity of these fractions to transfer cholesterol rapidly into the hepatocyte while, at the same time, slowing the rate of cholesterol mobilization from the liver.

Animals↗
PubMedDate not supplied

Gallbladder ejection fraction: an accurate evaluation of symptomatic acalculous gallbladder disease.

The use of cholecystokinin stimulation during cholescintigraphy to calculate the gallbladder ejection fraction has been associated with variable clinical results as a preoperative indicator for chronic acalculous cholecystitis and postoperative relief of biliary symptoms. A series of 56 consecutive patients was analyzed to determine the accuracy of a decreased gallbladder ejection fraction as a preoperative indicator for acalculous cholecystitis. Each patient had symptoms compatible with biliary disease. Each patient had a decreased gallbladder ejection fraction calculated by cholescintigraphy. The gallbladder ejection fraction was calculated using a 30-minute intravenous infusion of cholecystokinin at a dose of 0.02 microg/kg during cholescintigraphy. There was a 100% correlation found in this series of patients between a decreased gallbladder ejection fraction during cholescintigraphy, preoperative symptoms of gallbladder disease, and postoperative pathology evidence of acute or chronic cholecystitis. Only 1 patient had less than a complete resolution of her preoperative symptomatology after laparoscopic removal of her gallbladder. This patient had irritable bowel disease, which was diagnosed postoperatively. Six symptomatic patients with a gallbladder ejection fraction between 35% and 60% were also treated by laparoscopic removal of the gallbladder with complete resolution of their preoperative symptomatology. The use of a 30-minute infusion of cholecystokinin at a dose of 0.02 microg/kg to calculate the gallbladder ejection fraction during cholescintigraphy is an accurate test to preoperatively predict acalculous cholecystitis and postoperative relief of biliary symptoms. The gallbladder ejection fraction of less than 35% was abnormal. Cholecystectomy may be considered for patients whose gallbladder ejection fractions were calculated to be between 35% and 60% if the patient's symptoms were classical for biliary disease and have been present for 1 year. The use of a 30-minute intravenous infusion of cholecystokinin at a dose of 0.02 microg/kg to calculate the gallbladder ejection fraction during cholescintigraphy is an accurate test to preoperatively predict acalculous cholecystitis and postoperative relief of biliary symptoms.

Adult↗
PubMed1992

[Relationship between right ventricular ejection fraction and pulmonary pressure in man].

This clinical study analysed the changes in right ventricular ejection fraction induced by changes in right ventricular afterload using a new thermodilution catheter linked to a rapid response computer which allowed instantaneous measurements of the right ventricular ejection fraction. The first group comprised 16 patients referred for coronary angioplasty with single vessel disease (isolated proximal stenosis of one of the two main branches of the left coronary artery) and a normal left ventricular ejection fraction (> or = 55%) and mean pulmonary artery pressure of < 25 mmHg: right ventricular ejection fraction and mean pulmonary artery pressure were measured under basal conditions and after 60 seconds' coronary occlusion with the balloon catheter in order to assess the effects of the reactional increase in afterload on the right ventricular ejection fraction. The second group comprised 11 patients with dilated primary cardiomyopathy with decreased left ventricular ejection fraction (< 50%) and mean pulmonary artery pressure > or = 25 mmHg: the right ventricular ejection fraction and mean pulmonary artery pressure were measured under basal conditions and after intravenous trinitrin (performed to evaluate the pulmonary reaction to vasodilators) in order to analyse the effects of the reduction of afterload on right ventricular ejection fraction. Negative linear correlations were observed between the right ventricular ejection fraction and mean pulmonary artery pressure under basal conditions (r = -0.72; p < 0.005) and between the right ventricular ejection fraction and mean pulmonary artery pressure after changing the conditions of afterload (r = -0.82; p < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1976

Human transfer factor: fractionation and biologic activity.

Human transfer factor (TF) was fractionated by exclusion chromatography and the fractions were tested for biologic activity in vivo and in vitro. Specific TF activity in vivo was found to reside in the major UV-absorbing peak (Fraction III). Fraction III eluted at 2.7 X V(O) and transferred tuberculin, candida, or KLH-reactivity to previously negative recipients. Fraction III from nonreactive donors was ineffective. When the fractions were tested in vitro, we found that both the mitogenic activity of whole TF and the suppressive activity to mitogen activation when present in TF was found in Fraction I. Fraction III contained components responsible for augmentation of PHA and PWM responses. In addition, Fraction III contained the component responsible for antigen-dependent augmentation of lymphocyte transformation. Fraction IV was suppressive to antigen-induced lymphocyte transformation. These data suggest that TF preparations contain components which can affect immune reactions in both specific and nonspecific ways.

Antigens↗
PubMed2002

Effects of Maitake mushroom fractions on blood pressure of Zucker fatty rats.

A link exists between insulin resistance and many chronic disorders of aging including advancing-age. A safer means to prevent or, at least, slow the erosion of insulin sensitivity would provide a novel approach to better health. We compared the ability of a specific extract labeled fraction SX, as well as whole Maitake powder, fraction ES and fraction D of Maitake to influence SBP and various pertinent biochemical parameters when given orally to Zucker Fatty rats, a model of insulin resistance and type 2 diabetes mellitus. A secondary gain was the ability to ascertain the effects of bitter melon, olive oil, and sesame oil alone and combined with fraction SX to influence SBP. We found that a water-soluble fraction obtained from Maitake mushroom (SX) lowers SBP and fasting blood glucose significantly over the three to six weeks of study. While whole Maitake fraction lowered SBP effectively, the effects on fasting blood sugar were not apparent under the conditions of study. In contrast to fraction SX and fraction D, developed primarily to enhance immunity and suppress tumor development and growth, has essentially no effect on SBP under the conditions examined. An ether soluble fraction designated ES lowers SBP significantly. Interestingly, olive oil, unlike sesame oil, also lowers SBP. Finally, bitter melon and a combination of SX plus bitter melon also lower SBP. We conclude that fraction SX of Maitake mushroom may be useful to treat insulin resistance alone or combined with other natural products such as bitter melon and niacin-bound chromium.

Agaricales↗
PubMed1987

Inflammatory mediators and modulators released in organ culture from rabbit skin lesions produced in vivo by sulfur mustard. III. Electrophoretic protein fractions, trypsin-inhibitory capacity, alpha 1-proteinase inhibitor, and alpha 1- and alpha 2-macroglobulin proteinase inhibitors of culture fluids and serum.

This is the third report in a series on the inflammatory mediators and modulators released in organ culture from skin lesions of various ages, which were produced in vivo in rabbits by the military vesicant, sulfur mustard (SM). It describes the electrophoretic protein fractions and trypsin-inhibitory capacities of the various culture fluids and the amounts of alpha 1-proteinase inhibitor and alpha-macroglobulin proteinase inhibitors in these fluids. With one-dimensional electrophoresis, the albumin and beta-globulin fractions of protein in culture fluids varied little with the development and healing of the SM lesions. These fractions proportionally resembled the corresponding fractions found in serum. The alpha 1-globulin fraction was proportionally smaller than the corresponding fractions of serum as the lesions healed. The alpha 2-globulin fraction was proportionally smaller than the corresponding fractions of serum at all stages of lesion development and healing. The gamma-globulin fraction was proportionally larger as the lesions healed. With two-dimensional electrophoresis, about 68%, 46%, and 35% of the protein spots in culture fluids from representative 1-day and 6-day SM lesions and normal skin, respectively, matched those from serum. In each case, the large, diffuse, serum albumin spot represented about two-thirds of the protein present. Thus, gravimetrically, in normal skin and in both developing and healing lesions, the extracellular proteins were 80-90% of serum origin. The trypsin-inhibitory capacity (TIC) per milligram protein in the culture fluids of healing lesions was markedly less than the TIC per milligram protein in the fluids of peak lesions. This decrease correlates well with the decrease found in the alpha 1-globulin fraction, which contains alpha 1-antiproteinase (alpha 1-PI) (and alpha 1-macroglobulin [alpha 1M] in rabbits). The alpha 1PI and the alpha 1M-alpha 2M proteinase inhibitors were identified in the culture fluids by means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blots, specific antibodies, and the immuno-peroxidase technique. The levels of both free and proteinase-complexed alpha 1PI and alpha M inhibitors in the culture fluids decreased as the lesions healed. In both developing and healing lesions, at least half of the alpha 1PI and alpha M inhibitors seemed to be complexed with proteinases. Thus, serum seems to be a major source of unbounded extracellular protein within acute inflammatory lesions, and serum proteinase inhibitors seem to be the host's major defense against local damage by proteinases from serum, infiltrating leukocytes, and activated fibroblasts.

Aging↗
PubMed1988

Immunotherapy with Chinese medicinal herbs. I. Immune restoration of local xenogeneic graft-versus-host reaction in cancer patients by fractionated Astragalus membranaceus in vitro.

The in vitro immunomodulatory activity of fractions derived from Astragalus membranaceus, an herb commonly used in the practice of traditional Chinese medicine, was first screened by studying their individual effects on mononuclear cells (MNC) derived from healthy normal donors using the local xenogeneic graft-versus-host reaction (XGVHR). Sephacryl S-200 column-separated Fraction 3 (MW 20,000-25,000) along with its crude extract precursor, Fraction 7, and another crude extract derivative, Fraction 8, were equally augmentative (p less than 0.05) in their effect on MNC from normal donors. These three active fractions were further studied on MNC derived from 13 cancer patients. Using again the local XGVHR as a model assay for T-cell function, preincubation of MNC derived from cancer patients with Fraction 3 induced a significant increase in local XGVHR (compared to untreated cells) with a mean +/- SD of 151.34 +/- 46.02 mm3 vs 57.80 +/- 16.44 mm3; p less than 0.001. Fractions 7 and 8 likewise induced significant increases in local XGVHR (109.14 +/- 19.32 mm3 versus 50.91 +/- 17.39 mm3; p less than 0.001 and 119.74 +/- 18.33 mm3 versus 48.77 +/- 16.17 mm3; p less than 0.001, respectively). The augmented immune reactions which were induced by either Fraction 3 or Fraction 8 (but not by Fraction 7) in MNC derived from cancer patients, each significantly exceeded the local XGVHR observed in the untreated MNC derived from normal donor controls with a relative reference index (ratio) of 1.60 +/- 0.48 and 1.23 +/- 0.17 respectively; p less than 0.005.(ABSTRACT TRUNCATED AT 250 WORDS)

Adjuvants, Immunologic↗
PubMed1988

Renal damage in mice after treatment with cisplatin and x-rays: comparison of fractionated and single-dose studies.

Functional kidney damage in mice was measured after bilateral irradiation with x-rays alone or in combination with cisplatin (c-DDP). A single drug dose (6 mg/kg) was injected 30 minutes before the first of four or eight x-ray doses, given as four fractions per day with a minimum interval of 5 hours between treatments. A 30-fraction schedule was also investigated, with 15 fractions given in the first week (3 fractions per day), followed by a 2-week rest period and another 15 fractions in the fourth week. The c-DDP (4 mg/kg) was administered 30 minutes before the first fraction of each week, giving a total drug dose of 8 mg/kg. Renal function was assessed monthly from 10 to 37 weeks after the start of treatment by the clearance of 51Cr-labeled EDTA. The combined treatment caused more kidney damage than either agent alone for all fractionation schedules. Enhancement of the radiation damage by c-DDP changed only slightly with fractionation; dose enhancement factors were 1.2 for 1 fraction to 1.3 for 30 fractions. Modeling studies showed that this was consistent with the additive toxic effects of the two agents. There was no change in the alpha/beta for renal damage after x-rays plus c-DDP, compared with x-rays alone (alpha/beta = 1.9 Gy), implying that there was no reduction in repair and no modification of the x-ray response by c-DDP.

Animals↗
PubMed1986

Isolation of differentiated membrane domains from Escherichia coli and Salmonella typhimurium, including a fraction containing attachment sites between the inner and outer membranes and the murein skeleton of the cell envelope.

Cell envelopes of Salmonella typhimurium and Escherichia coli were disrupted in a French pressure cell and fractionated by successive cycles of sedimentation and floatation density gradient centrifugation. This permitted the identification and isolation of several membrane fractions in addition to the major inner membrane and murein-outer membrane fractions. One of these fractions (fraction OML) accounted for about 10% of the total cell envelope protein, and is likely to include the murein-membrane adhesion zones that are seen in electron micrographs of plasmolyzed cells. Fraction OML contained inner membrane, murein, and outer membrane in an apparently normal configuration, was capable of synthesizing murein from UDP-[3H]N-acetylglucosamine and UDP-N-acetylmuramylpentapeptide and covalently linking it to the endogenous murein of the preparation, and showed a labeling pattern in [3H]galactose pulse-chase experiments that was consistent with its acting as an intermediate in the movement of newly synthesized lipopolysaccharide from inner membrane to outer membrane. The fractionation procedure also identified two new minor membrane fractions, with characteristic protein patterns, that are usually included in the region of the major inner membrane peak in other fractionation procedures but can be separated from the major inner membrane fraction and from contaminating flagellar fragments by the subsequent floatation centrifugation steps.

Bacterial Proteins↗
PubMed1987

Cell fractions from rat rib growth cartilage. Morphological and X-ray microanalytical investigation.

For in vitro studies of differentiation and proliferation of chondrocytes, a need arose to prepare enriched cell fractions for analysis of the effects of different growth promoting factors. Therefore chondrocytes were isolated from rat rib growth cartilage in young rats by collagenase digestion and subsequently three cell fractions were prepared by centrifugation in a step gradient of Percoll. In a previous paper, matrix molecules synthesized by each fraction were characterized biochemically. In the present study, ultrastructure and elemental content of the fractionated chondrocytes were analyzed by scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray microanalysis. DNA-synthetic activity was measured by means of autoradiography of 3H-thymidine incorporating cells. Both morphology and elemental concentrations differed between fractions and were characteristic for each fraction. The cell fraction with the lowest density consisted of large, polygonal cells that became flattened in culture. The reduced synthetic activity and markedly lowered K content of these cells suggest that they originate from the hypertrophic zone of the growth plate. The cells in the fraction with the highest density were rather homogeneous in size and shape, and had a well developed rough endoplasmic reticulum and Golgi complex, characteristic of proliferating and resting chondrocytes. Concentrations of P and K were also significantly higher in this fraction. The fraction with intermediate density contained an admixture of cells with a predominance of proliferating cells with high DNA-synthetic activity.

Animals↗
PubMed1987

Biochemical and morphological effects of cigarette smoke condensate and its fractions on normal human bronchial epithelial cells in vitro.

We investigated the effect of cigarette smoke condensate (CSC), two basic fractions (BIa and BIb) of CSC, the ethanol-extracted weakly acidic fraction (WAe), and the methanol-extracted neutral fraction (Nmeoh) on the clonal growth rate, plasminogen activator (PA) activity, cross-linked envelope (CLE) formation, and ornithine decarboxylase activity, epidermal growth factor (EGF) binding, thiol levels, and DNA single strand breaks in cultured human bronchial cells. Neither CSC nor any of the fractions were mitogenic over the range 0.01-100 micrograms/ml. All were growth inhibitory at higher concentrations. The 40% growth inhibitory concentrations for CSC, BIa, BIb, WAe, and Nmeoh were 10, 10, 10, 3, and 1 micrograms/ml, respectively. Effects on CLE formation, morphology, PA, and ornithine decarboxylase activities, EGF binding, and thiol levels were evaluated using 40% growth inhibitory concentrations. We found that CSC and all fractions caused an increased formation of CLEs, from a baseline of 0.5% in the untreated cells to a maximum increase of 25% induced by Nmeoh. A squamous morphological change was observed within 1 h after exposure to Nmeoh, WAe, and CSC. The BIa and BIb fractions had little effect. Only Nmeoh increased PA significantly, from 2.5 +/- 0.4 to 5.1 +/- 0.3 units/mg cellular protein. CSC and the WAe and Nmeoh (Nmeoh greater than WAe greater than CSC) fractions caused a decrease in EGF binding, in each case reaching a maximum effect after a 10-12-h incubation. This effect on EGF binding was further characterized in the case of Nmeoh. In untreated normal human bronchial epithelial cells, by Scatchard analysis the kd was 2.0 nM and there were 1.2 X 10(5) receptors/cell. In cells incubated in medium containing Nmeoh (3 micrograms/ml) the kd was 3.2 nM and there were 1.1 X 10(5) receptors/cell. Thus, inhibition of EGF binding by Nmeoh was due primarily to a decrease in the affinity. At the 40% growth inhibitory concentrations neither CSC nor any of the fractions significantly affected intracellular thiol levels. While a 3-h incubation in medium containing CSC caused significant DNA single strand breaks only at a concentration of 100 micrograms/ml, Nmeoh caused a marked effect at 5 micrograms/ml. Neither CSC nor any of the fractions had an effect on ornithine decarboxylase activity. Due to the effects of the Nmeoh fraction on growth, morphology, EGF binding, PA activity, and formation of single strand breaks we consider it to be the most likely portion of CSC to contain compounds with actions similar to those of the phorbol ester, indole alkaloid, and polyacetate tumor promoters.

Bronchi↗
PubMed1985

Comparative studies on adjuvanticity of Klebsiella O3 lipopolysaccharide and its lipid A and polysaccharide fractions.

Previously, we found that Klebsiella O3 lipopolysaccharide (KO3 LPS) exhibits very strong adjuvant activity in augmenting the delayed-type hypersensitivity and antibody responses to protein antigens, and also strong ability to enlarge the regional lymph node in mice. By hydrolysis in 1% acetic acid at 100 degrees for 1 hr, KO3 LPS was dissociated into 54-60% polysaccharide fraction and 25-27% lipid A fraction. The lipid A fraction thus prepared retained lethal toxicity for mice, whereas the polysaccharide fraction was essentially non-toxic. However, neither the lipid A fraction nor the polysaccharide fraction could reproduce the strong adjuvanticity of KO3 LPS, and a simple mixture of these two fractions also failed to do so. It is therefore concluded that, for expression of the strong adjuvanticity of KO3 LPS, both the lipid A and polysaccharide moieties are indispensable and must be combined in the form of LPS. By contrast, administration of relatively large amounts of the lipid A fraction alone could elicit enlargement of the regional lymph node to the same degree as that attained by KO3 LPS. The regional lymph node-enlarging activity of the lipid A fraction in lesser amounts was enhanced by addition of the polysaccharide fraction. It is therefore likely that there is no direct correlation between adjuvant activity of the LPS or its derivatives, and their regional lymph node-enlarging activity.

Adjuvants, Immunologic↗
PubMed1985

[Effectiveness of the radiation therapy of lung cancer with conventional and median dosage fractionation].

A total of 202 patients were studied: 100 patients received radiotherapy of a primary tumor under conditions of mean fractionation and 102 under conditions of common fractionation. In common fractionation a single focal dose was 2 Gy, 5 times a week, a summary dose 50-60 Gy. In mean fractionation a single focal dose was 3 Gy, 3 times a week for 6 week up to a sum of 54 Gy which was equivalent to 60 Gy in common fractionation. In mean fraction 58 patients received radiotherapy only, 42 radiotherapy with adjuvant chemotherapy. In common fractionation the patients' 1,3 and 5-year survival rates for the control group were 52.8, 14.4 and 10.2% respectively. Under conditions of mean fractionation the 3-year survival rate was 14.2%, i. e. similar to that in the control group. In chemoradiotherapy the 3-year survival rate was 12.4% that might be due to the fact that in spite of Stage III these patients' condition was grave. Pulmonary radiation reaction established by x-ray within 4-6 mos. after the termination of therapy with mean fractionation were marked in 63 of 81 patients, whereas in common fractionation in 30 of 90 patients only.

Adenocarcinoma↗
PubMed1985

[Evaluation of left ventricular ejection fraction in coronary disease patients by the gated blood pool method and cineangiography. Critical analysis of divergences between the 2 methods].

In order to assess the reliability of left ventricular ejection fraction as estimated by gated blood pool method, radionuclide angiography (LAO) and single plane (RAO) contrast cineangiocardiography were performed within 14 days in 60 patients with coronary artery disease. The mean value of radionuclide ejection fraction was found to be 55 +/- 16%; contrast cineangiographic ejection fraction was 57 +/- 15%; r = 0.92. In 23 patients with previous anterior myocardial infarction gated blood pool method was found to underestimate left ventricular ejection fraction when compared with contrast cineangiography. The observed underestimation was wide significant in 11 patients with previous anterior infarction, low (less than 50%) radioisotopic ejection fraction and septal akinesia and/or apical dyskinesia; radionuclide ejection fraction = 33 +/- 8%; contrast cineangiographic ejection fraction = 42 +/- 9%; r = 0,76. This study confirms that the values of left ventricular ejection fraction as estimated by gated blood pool method in coronary patients are quite reliable; moreover, the intrinsic variability of the data is low. This may be not true in patients with previous anterior myocardial infarction. The Authors discuss the possible causes of disagreement between radioisotopic and contrastographic ejection fraction in patients with previous anterior infarction and poor left ventricular function: physical problems of measuring ejection fraction by gated blood pool in dilated ventricles; possible mistakes in evaluating blood pool due to the low mobility of the blood mass nearest to the scintillation camera; inhability of contrast cineangiography in RAO to recognize the interventricular septum and evaluate its kinetic abnormalities; unreliability of the geometrical model of revolution elypsoid in calculating end-systolic volumes in ventricles with abnormal wall-kinesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Cineangiography↗
PubMed1977

Differentiation between various effects of cytotoxic fractions of lymphocyte culture medium.

This paper describes the partial characterization of supernatants derived from mitogen stimulated lymphocytes by ammonium sulfate precipitation, ultrafiltration on Hollow-Fiber beakers and gelchromatography. Fractions from these purification procedures were tested on FL-target cells and the following target cell alterations were measured: RNA- and protein synthesis, 3H-TdR incorporation, cell number and lysis of target cells. Target cell alterations of control fractions from supernatants of non-stimulated lymphocytes, from culture medium and from FCS were compared to the effects of fractions from activated lymphocytes. 3H-TdR incorporation was not only inhibited by the fractions of activated lymphocyte cultures but also by fractions of various controls. Inhibition of 3H-TdR incorporation disappeared when control fractions were serially diluted. Only fractions of supernatant from activated lymphocytes could lyse target cells. It were the same fractions which still inhibited 3H-TdR incorporation of target cells after serial dilution and which showed stimulating effects on RNA synthesis. MW of fractions which were differentiated from control fractions with respect to target cell lysis were: 90,000, 45,000 and lower than 20,000 d.

Cell Line↗
PubMedDate not supplied

[Study of fractionated rat liver and sea urchin chromatin].

Two chromatin fractions were isolated from rat liver nuclei and from sperm of the sea urchin, Strongylocentrotus intermedius, by chromatin treatment with DNAase II with subsequent fractionation of the resultant fragments via their precipitation with MgCl2 solution. The analysis of distribution between these fractions of rapidly in vivo labeling RNA associated with chromatin and the in vitro investigation of template activity of isolated chromatin fractions allowed to conclude that one of the fractions is transcriptionally active and the other is inactive. The active chromatin fraction, similarly to the inactive one, contains all five histones. Unlike the latter, however, the former fraction is enriched in non-histone proteins and impoverished in histone H1. It is shown that the active chromation fraction of rat liver is composed of small fragments heterogenous in size. Rapidly synthesizing RNA in this fraction is mainly associated with mononucleosomal particles. Data on electrophoretic mobility of DNA fragments isolated from the active chromatin fraction from rat liver show that transcriptionally active sites of chromatin retain the nucleosomal structure.

Animals↗
PubMed1995

Characterization of an additional articular cartilage vesicle fraction that generates calcium pyrophosphate dihydrate crystals in vitro.

OBJECTIVE: We previously identified a unique fraction of porcine articular cartilage vesicles, sedimentable at 8 x 10(6) g/min, which generate calcium pyrophosphate dihydrate crystals (CPPD) in vitro. We sought to identify and characterize other fractions of articular cartilage digest, sedimentable at lower g forces, which may also contain mineralizing vesicles. METHODS: Electron microscopy and alkaline phosphatase and nucleoside triphosphate pyrophosphohydrolase (NTPPPH) assays were used to analyze each fraction. Radiometric mineralization assays, Fourier transform infrared (FTIR) spectroscopy, and compensated polarized light microscopy were used to analyze crystals formed by these fractions. RESULTS: Vesicles of varying sizes identical to epiphyseal cartilage matrix vesicles were seen in all sedimentable fractions examined, but were the exclusive component of fractions sedimentable at 3 x 10(6) g/min, termed the heavy vesicle fraction (HVF), and at 8 x 10(6) g/min, now termed the light vesicle fraction (LVF). All vesicle containing fractions supported ATP dependent calcium pyrophosphate precipitation. The HVF and LVF precipitated 30 x more calcium than vesicle poor supernatant (p < 0.01) and 1.5-4 x more than cell-free unfractionated digest (p < 0.01). HVF differed from LVF in that it contained 3-4 x higher NTPPPH specific activity (p < 0.05). HVF resembled LVF in that both precipitated crystals consistent with CPPD by FTIR spectroscopy and compensated polarized light microscopy. CONCLUSION: These data expand our previous estimate of the total number of vesicles available for biologic mineralization and demonstrate heterogeneity of vesicle fractions. They support a key role for vesicles in CPPD crystal formation.

Alkaline Phosphatase↗