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At least 73 records · Page 4Linked to original sources
PubMed1997

Improved retention of the EMS activation component (EMSAC) in adult CPR education.

This study was undertaken to determine whether using a model-telephone to simulate the emergency medical services activation component (EMSAC) during adult cardiopulmonary resuscitation (CPR) training practice would lead to better retention of this component during end-of-class assessment. In a prospective randomized manner, 233 medical professionals and lay-persons taking American Heart Association (AHA) CPR classes were evaluated for EMSAC retention during CPR skills performance at the end of class. During the assessment correct versus incorrect activation of EMS was noted. Subject response by age, exposure to previous CPR training, and medical professional or lay-person status was examined. Differences in results among instructors also were examined. Overall, those in the group using the model-telephone remembered to activate EMS correctly more frequently than those in the group not using the phone (69 vs 52%, P = 0.009). The < 30 age group was unaffected by the use of the phone (P = 0.85). The group between 30 and 50 years of age did significantly better with the use of the phone (P = 0.007), as did those 50 years of age and older (P = 0.03). Previous CPR training did not affect the response (P = 0.18). We conclude that use of the model-telephone improved EMSAC retention significantly overall except in the < 30 year-old age group. We recommend using the model-telephone in future adult CPR classes.

Adolescent↗
PubMedDate not supplied

[Analysis of the informational and activating components of reinforcement in a conditioned reflex experiment].

The reinforcement in adaptive behaviour performs at least two functions: satisfaction of specific need (activational component) and estimation of signal significance of the conditioned stimulus while comparing the nervous model of the stimulus with current afferentation (informational component). In usual conditioning experiments with permanent reinforcement these components concide and therefore do not differ. However, they may be separated in the case of probabilistic reinforcement by changing stimuli contingency and shifting motivational level. With this aim the diagrams of probabilistic stimuli and reactions space, semantic and pragmatic matrices are worked out, allowing to estimate correlations of these parameters of conditioning experiments. Comparative psychophysiological investigations showed the possibility of determination of species peculiarities in behavioural choice strategies among various animals under above mentioned conditions.

Adaptation, Physiological↗
PubMed1997

Glycyrrhizin, an active component of licorice roots, reduces morbidity and mortality of mice infected with lethal doses of influenza virus.

The antiviral effect of glycyrrhizin (GR), an active component of licorice roots, was investigated in mice infected with influenza virus A2 (H2N2). When mice that had been exposed to 10 50% lethal doses of the virus were treated intraperitoneally with 10 mg of GR per kg of body weight 1 day before infection and 1 and 4 days postinfection, all of the mice survived over the 21-day experimental period. At the end of this period, the mean survival time (in days) for control mice treated with saline was 10.5 days, and there were no survivors. The grade of pulmonary consolidations and the virus titers in the lung tissues of infected mice treated with GR were significantly lower than those in the lung tissues of infected mice treated with saline. GR did not show any effects on the viability or replication of influenza virus A2 in vitro. When splenic T cells from GR-treated mice were adoptively transferred to mice exposed to influenza virus, 100% of the recipients survived, compared to 0% survival for recipient mice inoculated with naive T cells or splenic B cells and macrophages from GR-treated mice. In addition, the antiviral activities of GR on influenza virus infection in mice were not demonstrated when it was administered to infected mice in combination with anti-gamma interferon (anti-IFN-gamma) monoclonal antibody. These results suggest that GR may protect mice exposed to a lethal amount of influenza virus through the stimulation of IFN-gamma production by T cells, because T cells have been shown to be producer cells of IFN-gamma stimulated with the compound.

Adoptive Transfer↗
PubMed1978

Approximative molecular weight of the active component in toxoplasmin.

The approximative molecular weight of toxoplasmin -- a skin reactive extract from Toxoplasma gondii -- was estimated by ultrafiltration through different Amicon membranes. The activity of the filtered and unfiltered product was compared with the aid of intradermal test on humans. The results indicate that the molecular weight of an active component in toxoplasmin is in the range from 10 000 to 50 000.

Antigens↗
PubMed1995

Localization of the genes for the 100-kDa complement-activating components of Ra-reactive factor (CRARF and Crarf) to human 3q27-q28 and mouse 16B2-B3.

Human and mouse genes for the complement-activating component (P100) of Ra-reactive factor, a novel bactericidal factor (CRARF and Crarf), were mapped to R-banded metaphase chromosomes by fluorescence in situ hybridization with human and mouse P100 cDNA 2.7 and 2.0 kb long, respectively. The localization of fluorescent signals showed that CRARF and Crarf mapped to human 3q27-q28 and mouse 16B2-B3, respectively. This evidence is consistent with the previous assumption that the distal portion of the long arm of human chromosome 3 is homologous to the proximal portion of mouse chromosome 16.

Animals↗
PubMed1999

Migration behavior and separation of active components in Glycyrrhiza uralensis Fisch and its commercial extract by micellar electrokinetic capillary chromatography.

A micellar electrokinetic capillary chromatography (MECC) method for the separation and determination of five components, glycyrrhizic acid (GA), glycyrrhetinic acid (GTA) and 3,4'-dimethoxy-5-hydroxychalone, fermononetin and isoliquiritigenin, in extracts of Glycyrrhiza uralensis Fisch root was developed. Migration behavior of these analytes was studied by the systematic examination of the borate and sodium dodecyl sulfate (SDS) concentrations in the run buffer. The optimum separation for these analytes was achieved using 10 mmol l(-1) of tetraborate and 25 mmol l(-1) of SDS as the running buffer, with 17 kV of applied voltage. All experiments were performed using a 50.0 cm (42.4 cm effective length)x75 microm I.D. of fused-silica capillary. The apparent pKa values of GA and GTA and the binding constants for the association between the above five analytes and SDS were calculated in this study. A comparison of the extraction efficiency for GA and GTA from Glycyrrhiza uralensis Fisch root was made using ethanol, distilled water and chloroform as extraction reagents, respectively. These results provided very useful information to select the proper solvent to extract the desired components in Glycyrrhiza uralensis Fisch. The MECC method established in this paper was employed to analysis the above five active components.

Acids↗
PubMed1985

Comparison of fluorescence and photodynamic activities of whole hematoporphyrin derivative and its enriched active components.

The in vivo biologic activities of the hematoporphyrin derivative (Photofrin) and the enriched, so-called "active fraction" (Photofrin II) were determined by measuring the necrosis produced in implanted tumors in DBA/2Ha mice exposed to various total doses of light (20-100 J/cm2) after ip administration of 10 mg/kg standard doses of either Photofrin or Photofrin II. Total relative percentage increase in fluorescence in tumor tissue, as compared to fluorescence in control tissue, also was measured for both Photofrin and Photofrin II. In response to total light doses (630 nm) of 40-100 J/cm2, mice that received Photofrin had comparable amounts of tumor necrosis to those mice that received Photofrin II. At doses of 40-60 J/cm2, 80% tumor destruction resulted, and at 80-100 J/cm2, tumor destruction was 100%. However, at a total light dose of 20 J/cm2, the tumors that received Photofrin II exhibited 60-80% tumor necrosis, whereas those animals that received Photofrin had only small areas of patchy necrosis associated with signs of vascular thrombosis and hemorrhage into the surrounding perivascular stroma. A 25.2% total increase in maximal tissue fluorescence over that in controls was observed for animals that received Photofrin II, as compared to 13.9% for those animals that received Photofrin. It is concluded that the greater demonstrable efficacy of treatment with Photofrin II, as compared to treatment with Photofrin, is due to enrichment of those nonpolar hydrophobic components of the hematoporphyrin derivative mixture that are thought to be primarily responsible for the in vivo biologic activities.

Animals↗
PubMed1997

Two isoforms of the mouse ether-a-go-go-related gene coassemble to form channels with properties similar to the rapidly activating component of the cardiac delayed rectifier K+ current.

HERG, the human ether-a-go-go-related gene, encodes a K(+)-selective channel with properties similar to the rapidly activating component of the delayed rectifier K+ current (IKr). Mutations of HERG cause the autosomal-dominant long-QT syndrome (LQTS), presumably by disrupting the normal function of IKr. The current produced by HERG is not identical to IKr, however, and the mechanism by which HERG mutations cause LQTS remains uncertain. To better define the role of Erg in the heart, we cloned Merg1 from mouse genomic and cardiac cDNA libraries. Merg1 has 16 exons and maps to mouse chromosome 5 in an area syntenic to human chromosome 7q, the map locus of HERG. We isolated three cardiac isoforms of Merg1: Merg1a is homologous to HERG and is expressed in heart, brain, and testes, Merg1a' lacks the first 59 amino acids of Merg1a and is not expressed abundantly, and Merg1b has a markedly shorter divergent N-terminal cytoplasmic domain and is expressed specifically in the heart. The Merg1 isoforms, like HERG, produce inwardly rectifying E-4031-sensitive currents when heterologously expressed in Xenopus oocytes. Merg1a and HERG produce currents with slow deactivation kinetics, whereas Merg1a' and Merg1b currents deactivate more rapidly. Merg1b coassembles with Merg1a to form channels with deactivation kinetics that are more rapid than those of Merg1a or HERG and nearly identical to IKr. In addition, a homologue of Merg1b is present in human cardiac and smooth muscle. Thus, we have identified a novel N-terminal Erg isoform that is expressed specifically in the heart, has rapid deactivation kinetics, and coassembles with the longer isoform in Xenopus oocytes. This N-terminal Erg isoform may determine the properties of IKr and contribute to the pathogenesis of LQTS.

Amino Acid Sequence↗
PubMed1983

Fractionation of a whey growth factor for Streptococcus agalactiae into two active components containing proteins.

Previously three factors (F-1, F-2, F-3) that stimulated in vitro growth of Streptococcus agalactiae were separated from wheys of milk and colostrum by chromatographic procedures. Now F-1 was separated further into two active components, F-1a and F-1b, when rechromatographed on an anion exchange resin with distilled water as eluent. The stimulatory activity was associated with two protein peaks whereas a third protein peak that was eluted in those fractions containing lactose was not stimulatory. Most of the stimulatory activity (76 to 80%) and protein (90 to 93%) were retained by a filter with retention of greater than 1,000 MW. Two stimulatory factors were confirmed by separation of F-1 fractions by step-gradient elution on a column of octadecylsilica; one protein peak was found for each of the three solvents. Samples with protein eluted with .1 N formic acid and formic acid: methanol (1:1) had stimulatory activity, whereas the sample with protein eluted with 100% methanol was inactive. Results were similar when F-1 fractions were applied to Sep-Pak (muBondapack C18) cartridges and eluted with water, 50% methanol, and 100% methanol. Proteins in the Sep-Pak eluates with stimulatory activity (water and 50% methanol) were heterogeneous and different when separated by high-voltage paper electrophoresis. Proteose-peptone preparations with added lactose were chromatographed on columns of anion exchange resin, with distilled water as eluent, and produced two peaks of protein with elution volumes comparable to peaks 1 and 3. Lactose appeared to be a major factor in eluting the second protein peak.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Reconstitution of intercalator-induced DNA scission by an active component from nuclear extracts.

Treatment with intercalating agents causes formation of protein-associated DNA breaks in mammalian cells in culture and in the nuclei isolated from these cells. We found that this effect, when induced by the intercalator m-AMSA, required a component which could be dissociated from nuclei by 0.3 M NaCl. The effect was restored by combining the extracted nuclei with the nuclear extract. The active component of the extract eluted in gel filtration at a point corresponding to a molecular weight of 800 000. During its reaction with DNA, DNA-protein links and DNA breaks appeared in approximately equal frequencies. In this respect the reaction stimulated by m-AMSA resembled the reaction of a topoisomerase with DNA. However, intercalator-stimulated formation of protein-associated DNA breaks differed from the activity of the nuclear topoisomerase I in that there was a different optimum salt concentration and a different apparent molecular weight.

Aminoacridines↗
PubMed2001

Modified phosphatidylethanolamine as the active component of oxidized low density lipoprotein promoting platelet prothrombinase activity.

We analyzed the influence of the atherogenic oxidized low density lipoproteins (LDL) on the activity of the platelet prothrombinase complex, a major contributor to overall thrombin formation in vivo. Platelet dependent thrombin generation was found to be strongly stimulated by in vitro oxidized LDL. The enhancement was additive to that observed with the platelet agonist thrombin. Oxidized LDL increased the platelet binding of annexin-V, suggesting that the augmented surface exposure of aminophospholipids promoted the prothrombinase activity. All of the stimulatory activity of the oxidized LDL could be recovered in the microemulsions prepared from the lipid portion of the modified particles. Phospholipid vesicles were prepared containing the total lipids of the oxidized LDL but lacking specifically in one lipid component. Following the selective removal of the ethanolamine phospholipids (PE) from the LDL lipids, the platelet-dependent thrombin formation was markedly reduced. Vesicles enriched with the isolated PE fraction alone enhanced the thrombin generation. Analyses with autoxidized phospholipids indicated that oxidation products of unsaturated diacyl-PE were mainly responsible for the increased prothrombinase activity. Oxidized LDL and its PE fraction lost their stimulatory activity after treatment with NaCNBH(3), a chemical reductant of Schiff base adducts. Phospholipid vesicles supplemented with synthetic aldehyde-PE adducts largely reproduced the stimulation of the thrombin generation. We conclude that the oxidized LDL particles elicit a pronounced prothrombotic response by increasing the activity of the platelet prothrombinase complex. Specific oxidative modifications of the LDL-associated ethanolamine phospholipids are mainly responsible for this stimulation.

Blood Platelets↗
PubMed1994

Pseudorabies virus growth factor can be resolved into two active components.

Pseudorabies virus (PRV) growth factor (PRGF) which induces a transformed phenotype in normal MK-2 cells and represses the transformed phenotype of Hela cells was partially purified and resolved into two components (M(r) < 300 and < 180). Each of the PRGF components retained the transforming activity of the original factor in MK-2 cells but lost its transformation-repressing activity in Hela cells. The latter activity of PRGF could be reconstituted by simultaneous application of its two components. Two monoclonal antibodies against gII glycoprotein of PRV were able to neutralize both PRGF activities, thus supporting the previously suggested hypothesis that the PRV gene for glycoprotein gII might be involved in PRGF synthesis.

Animals↗
PubMed1999

Functional diversities of two activity components of circadian rhythm in genetical splitting mice (CS strain).

CS mice, an inbred strain, showed two distinctive characteristics in the circadian rhythm of locomotor activity: (1) large variation in the freerunning period, and (2) spontaneous rhythm splitting under continuous darkness. In the splitting rhythm there was a positive correlation between the freerunning period of the evening component and the activity time of the morning component. The phase-shifting effect of a 15-min light pulse was examined on the two activity components of the splitting rhythm. There were significant differences in the amount of light-induced phase response between the two components. A light pulse during the late subjective night induced a phase advance shift only in the morning component, while a light pulse during the early subjective night induced a phase delay shift only in the evening component. These results indicate functional diversities of the two activity components in the circadian locomotor rhythm of CS mice, and suggest that the circadian system in CS mice consists of two mutually coupled oscillators which have different circadian periods and different responsiveness to light. The CS mouse is a useful model to explore a genetic background of oscillator coupling in the circadian system of nocturnal rodents.

Animals↗
PubMed1994

Pharmacologically active components from a Peruvian medicinal plant, huira-huira (Culcitium canescens H. & B.).

The methanol extract of Huira-Huira (Culcitium canescens) showed analgesic effects in acetic acid-induced writhing and tail pressure tests, and it also produced potent prolongation of hypnosis induced by pentobarbital. The latter activity was used as an isolation-guide to determine the active components which were identified as dehydrocacalohastine, cacalohastine and cacalonol.

Analgesics↗
PubMed1999

Bacterial endotoxin is an active component of cigarette smoke.

BACKGROUND: Chronic bronchitis in cigarette smokers shares many clinical and histologic features with environmental lung diseases attributed to bacterial endotoxin (lipopolysaccharide [LPS]) inhalation. Experimental LPS inhalation mimics many of the acute effects of cigarette smoke in the lower airway. Therefore, we reasoned that LPS may be a biologically active component of cigarette smoke. DESIGN: The Limulus amebocyte lysate (LAL) assay was used to measure LPS in the tobacco and filter tip components of unsmoked 1R4F experimental cigarettes and commercially available "light" cigarettes, as well as in mainstream (MS) and sidestream (SS) smoke particles generated with an automated smoking machine and collected on ventilator mainflow filters. SETTING AND PARTICIPANTS: Blood LPS activity and plasma cytokine concentrations were measured in groups of healthy smokers and nonsmokers who reported to the walk-in clinic at the Baltimore VA Medical Center for unrelated complaints. MEASUREMENTS: Blood LPS levels were measured by LAL assay and plasma levels of tumor necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6), soluble TNF receptors I and II (sTNFR I and sTNFR II) were measured by enzyme-linked immunosorbent assay. RESULTS: Bioactive LPS was detected in both the tobacco portion (1R4F, 17.8+/-1.0 microg/cigarette; light, 26.8+/-7.3 microg/cigarette [mean+/-SE]) and filter tips (1R4F, 0.67+/-0.55 microg/cigarette; light, 0.70+/-0.39 microg/cigarette) of cigarettes. Bioactive LPS was also detected in both MS (1R4F, 120+/-64 ng/cigarette; light: 45.3+/-16 ng/cigarette) and SS smoke (1R4F, 18+/-1.5 ng/cigarette; light: 75+/-49 ng/cigarette). Although systemic absorption of inhaled LPS may occur, we failed to detect any differences between nonsmokers and smokers in median blood LPS levels (median values, 66.75 and 72.1 pg/mL, respectively; p = 0.55) or plasma concentrations of TNF-alpha (0 vs 0 pg/mL, respectively; p = 0.71), sTNFR I(1,469 vs 1,576 pg/mL, respectively), sTNFR II (2,011 vs 3,110 pg/mL, respectively), or IL-6 (8.8 vs 0 pg/mL, respectively; p = 0.20). CONCLUSIONS: Smoking one pack of cigarettes per day delivers a dose of respirable LPS that is comparable to the levels of LPS associated with adverse health effects in cotton textile workers. Thus, we suggest that the bioactive LPS in cigarette smoke may contribute to the pathogenesis of chronic bronchitis that develops in susceptible cigarette smokers.

Bronchitis↗
PubMed1987

Porphyrin derivatives having physical and chemical characteristics similar to those of the active components of hematoporphyrin derivative and with very strong photosensitizing effects.

The tumour-localizing fraction of hematoporphyrin derivative (Hpd) is thought to possess an essentially diporphyrin ether structure or, alternatively, a diporphyrin ester structure, the properties of which facilitate its retention in malignant cells and its biological activity on irradiation. To elucidate this problem further, we have synthesized the dimethyl, diethyl, dipropyl, di-n-butyl and di-iso-butyl ethers of hematoporphyrin. These ethers show chromatographic properties very similar to those of the active components of Hpd. Furthermore, they are much better photosensitizers in a cellular system than are crude Hpd or Photofrin II, and, like the components of Hpd, they are taken up and retained by cells according to their degree of non-polarity.

Carcinoma in Situ↗
PubMed2000

Evaluation of major active components in St. John's Wort dietary supplements by high-performance liquid chromatography with photodiode array detection and electrospray mass spectrometric confirmation.

A RP-HPLC method with photodiode array detection and LC-electrospray ionization (ESI) MS confirmation was established for the determination of major active components in St. John's Wort dietary supplement capsules. The samples alternatively were extracted with ethanol-acetone (2:3) using a 55 degrees C water-bath shaker or an ambient temperature ultrasonic bath. Extracts were separated by RP-C18 chromatography using a 95-min water-methanol-acetonitrile-trifluoroacetic acid gradient. The major components were identified by photodiode array detection and then confirmed by LC-ESI-MS. The quantification of components was performed using an internal standard (luteolin). This method may serve as a valuable tool for the quality evaluation of St. John's Wort dietary supplement products.

Calibration↗