Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “additive”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 577 records · Page 32Linked to original sources

[Energy metabolism of men in full pressure suit with additional pressure].

The energy metabolism of men in full pressure suit with additional pressure and without additional pressure were measured during rest and exercise. Results show that the rates of energy metabolism of men in full pressure suit with additional 28 kPa pressure and without additional pressure increased as the exercise load increased. The rates of energy metabolism of men in full pressure suit with additional 28kPa pressure had no significant difference during rest and 0.9W exercise, but significantly increased during 8.5 W exercise, as compared with that without additional pressure. It suggested that full pressure suit with 28 kPa did not affect human energy metabolism during rest, but affected during exercise.

Aerospace Medicine↗

Influence of binder properties, method of addition, powder type and operating conditions on fluid-bed melt granulation and resulting tablet properties.

The aim of the study was to investigate melt granulation in a laboratory scale fluid-bed granulator with respect to granule growth, granule properties and resulting tablet properties. The parameters investigated were method of addition of PEG (spray-on or addition as flakes), binder concentration, PEG type (3000, 4000 and 6000, sprayed-on), size (PEG 4000, added as three different sized flakes), powder type (two different sized lactose types and corn starch) and operating conditions (volume air flow and heating temperature). Addition of binder as flakes led to layering as a growth mechanism when the size of the flakes was high. Coalescence occurred when the size was low. Coalescence also occurred when spraying was the method of addition. Due to the greater viscosity of the PEG 6000 melt it produced bigger granules than 3000 or 4000. The influence of volume air flow was moderate and the influence of heating temperature in the range of 70-90 degrees C was very low with both methods of addition. The disintegration time of tablets from granules where PEG was added as flakes was shorter than from granules where PEG was sprayed-on. The latter method of binder addition led to tablets which did not disintegrate but eroded. This was apparently caused by formation of a binder matrix, which could not be destroyed by the disintegrant.

Drug Compounding↗

[Study on spectral properties of Chinese herbal medicines additives in cosmetic].

Chinese herbal medicines as additives in cosmetic can both keep the properties of cosmetic and have maintaining, health protection and remedial effect. Some of the Chinese herbal medicines can absorb ultraviolet and cure sunburn. This article mainly studies the spectral properties of several kinds of Chinese herbal medicine additives in cosmetic by ultraviolet and visible spectrophotometer, and analyses the ultraviolet absorption of the Chinese herbal medicine additives. It was shown that gynostemma pentaphyllum can absorb ultraviolet very well. It can be a promising natural additive in the health protection cosmetic. Codonopsis pilosula, floss chrysanthemum indicum, radix scutellariae and radix glycyrrhizae can absorb ultraviolet. They can also be the additives, while ligusticum wallichii can't absorb ultraviolet, so it can not be used as the sunburn protection additive.

Codonopsis↗

Combined addition of glutathione and iron chelators for decrease of intracellular level of reactive oxygen species and death of Chinese hamster ovary cells.

The combined addition of reduced form of glutathione (GSH) and iron chelators for decrease of the intracellular level of reactive oxygen species (ROSs) and death of Chinese hamster ovary (CHO) cells was investigated. The addition of GSH to the serum-free cultures of CHO cells markedly lowered the intracellular ROS level, which effect was comparable to that of the addition of serum (0.4, 10%) and might be due to the reduction of ROS. The addition of iron chelators, deferoxamine and aurintricarboxylic acid, to the serum-free cultures also decreased the intracellular ROS level and increased the residual concentration of viable cells during the serum-free maintenance culture, which should be due to the inhibition of the Fenton and Harber-Weiss reactions stimulating the synthesis of ROS. The combined addition of GSH and the chelators decreased ROS level and cell death more effectively compared with their single addition.

Journal Article↗

Repeated addition of insulin for dynamic control of apoptosis in serum-free culture of Chinese hamster ovary cells.

Repeated addition of insulin, together with an initial addition of the reduced form of glutathione (GSH) and a chelator, aurintricarboxylic acid (ATA), was proposed as a strategy for the dynamic control of apoptosis in serum-free culture of Chinese hamster ovary (CHO) cells. Insulin suppressed cell death in serum-free culture by means of lowering intracellular reactive oxygen species levels via an increase in the specific glucose consumption rate. This effect of insulin addition was found not only at 0 h but also at 48 h during serum-free cultivation. In consideration of the reduction of insulin by GSH, insulin was again added at 24 h following the initial addition during the serum-free cultivation. The repeated addition of insulin decreased cell death and increased the production of tissue plasminogen activator compared with the single addition at 0 h.

Journal Article↗

[Kinetic analysis of additive effect on desulfurization activity].

The additive effects of A12O3, Fe2O3 and MnCO3 on CaO sulfation kinetics were investigated by thermogravimetic analysis method and modified grain model. The activation energy (Ea) and the pre-exponential factor (k0) of surface reaction, the activation energy (Ep) and the pre-exponential factor (D0) of product layer diffusion reaction were calculated according to the model. Additions of MnCO3 can enhance the initial reaction rate, product layer diffusion and the final CaO conversion of sorbents, the effect mechanism of which is similar to that of Fe2O3. The method based isokinetic temperature Ts and activation energy can not estimate the contribution of additive to the sulfation reactivity, the rate constant of the surface reaction (k), and the effective diffusivity of reactant in the product layer (Ds) under certain experimental conditions can reflect the effect of additives on the activation. Unstoichiometric metal oxide may catalyze the surface reaction and promote the diffusivity of reactant in the product layer by the crystal defect and distinct diffusion of cation and anion. According to the mechanism and effect of additive on the sulfation, the effective temperature and the stoichiometric relation of reaction, it is possible to improve the utilization of sorbent by compounding more additives to the calcium-based sorbent.

Air Pollution↗

Will population bottlenecks and multilocus epistasis increase additive genetic variance?

We apply new analytical methods to understand the consequences of population bottlenecks for expected additive genetic variance. We analyze essentially all models for multilocus epistasis that have been numerically simulated to demonstrate increased additive variance. We conclude that for biologically plausible models, large increases in expected additive variance--attributable to epistasis rather than dominance--are unlikely. Naciri-Graven and Goudet (2003) found that as the number of epistatically interacting loci increases, additive variance tends to be inflated more after a bottleneck. We argue that this result reflects biologically unrealistic aspects of their models. Specifically, as the number of loci increases, higher-order epistatic interactions become increasingly important in these models, with an increasing fraction of the genetic variance becoming nonadditive, contrary to empirical observations. As shown by Barton and Turelli (2004), without dominance, conversion of nonadditive to additive variance depends only on the variance components and not on the number of loci per se. Numerical results indicating that more inbreeding is needed to produce maximal release of additive variance with more loci follow directly from our analytical results, which show that high levels of inbreeding (F > 0.5) are needed for significant conversion of higher-order components. We discuss alternative approaches to modeling multilocus epistasis and understanding its consequences.

Biological Evolution↗

An in-vitro investigation of the effect of a water additive and a new acidic primer on the tensile bond strength of composite resin to human enamel and dentine.

The aim of this study was to investigate the effect of a water additive on the bond strength of a composite restorative material to enamel and dentine which have undergone a range of surface treatments regimes. Human enamel and dentine specimens were prepared and divided into 3 surface treatment groups. Composite resin restorative material was bonded to the surface prepared enamel and dentine specimens. The tensile bond strength of the composite resin was measured using a Lloyd's testing machine. The tensile bond strength of composite resin to etched enamel surfaces using a standard etch technique was significantly greater than that to dentine (p < 0.05). For those specimens subjected to the addition of the water additive 'Alpron' the bond strength to the enamel was still significantly greater than to the dentine (p< 0.005). The addition of 'Alpron' to the water significantly improved the bond strength of composite to enamel and dentine when etched and placed with 'Prime&BondNT' (p < 0.05). There was no significant difference in bond strength of enamel and dentine specimens bonded using Xeno III (p> 0.05). However, the bond strength of dentine specimens bonded with Xeno III was significantly greater than other dentine specimens bonded with Prime&BondNT (p< 0.05). For those groups of specimens which included the water additive 'Alpron' in the regime, the tensile bond strength of the composite resin restorative material to enamel and dentine was greater than for those non water additive groups. The tensile bond strength of composite resin bonded to enamel surfaces prepared with 'Alpron' was significantly higher than that bonded to dentine surfaces.

Acid Etching, Dental↗

Treatment of NIDDM patients with secondary failure to glyburide: comparison of the addition of either metformin or bed-time NPH insulin to glyburide.

In this study we compared, in 12 NIDDM patients with secondary failure to glyburide, the effect of adding either a single, low-dose bed time NPH insulin injection (0.2 U/Kg) or an oral metformin administration (500 mg x 3) to the previously ineffective sulfonylurea treatment. The addition of both insulin and metformin treatment significantly improved fasting plasma glucose, post-prandial plasma glucose and %HbA1. The effect of both combined therapies was already evident and maximal after 2 weeks of treatment. The addition of bed-time NPH insulin caused a greater decrease of fasting plasma glucose, although the difference with the addition of metformin was not significant. In contrast, the average post-prandial plasma glucose decrease was significantly greater after metformin addition. The addition of bed-time NPH insulin caused a significant increase in average body weight, while after metformin addition, average body weight was unchanged; no change in the average cholesterol and triglyceride level was observed after either combined therapies.

Adult↗

[Effects of addition of calcium phosphates on the properties of gypsum].

Calcium hydrogen phosphate (CHP), calcium hydrogen phosphate dihydrate (CHPD) and calcium sulfate dihydrate (gypsum) crystals were added to calcium sulfate hemihydrate as gypsum model materials for improvement of the mechanical properties. The compressive and the bending strength of the hardened mixture were improved by the addition of CHPD, while the addition of CHP and gypsum crystals had no effect. The setting time was markedly reduced by the addition of CHPD, but remarkably increased in the case of CHP crystals. On the other hand, the setting expansion was decreased by the addition of CHP and CHPD crystals. Based on the observation of the surface profile of the calcium sulfate hemihydrate set in contact with glass, and scanning electron microscopy (SEM) of the fractured surface of the hardened mixture, the surface roughness was markedly decreased by the addition of CHPD. When the crystals were added to the metastable solution of calcium sulfate supersaturated with respect to gypsum, the presence of gypsum crystals deposited on the CHPD surface was confirmed by atomic absorption analysis, fourier transform infrared spectroscopy. SEM and electron X-ray microanalysis. Therefore, epitaxial growth of gypsum occurred on the CHPD surface and the addition of CHPD improved the mechanical properties of the gypsum materials.

Calcium Phosphates↗

Isoleucyl-tRNA synthetase from Escherichia coli MRE 600. Different pathways of the aminoacylation reaction depending on presence of pyrophosphatase, order of substrate addition in the pyrophosphate exchange, and substrate specificity with regard to ATP analogs.

The substrate specificity of isoleucyl-tRNA synthetase from Escherichia coli MRE 600 with regard to ATP analogs has been compared with the results obtained with isoleucyl-tRNA synthetase from yeast. The enzyme from E. coli is less specific, the two enzymes exhibit different topographies of their active centres. The order of substrate addition to isoleucyl-tRNA synthetase from E. coli MRE 600 has been investigated by bisubstrate kinetics, product inhibition and inhibition by substrate analogs. The inhibition studies were done in the aminoacylation and in the pyrophosphate exchange reaction, the aminoacylation was investigated in the absence and presence of inorganic pyrophosphatase. As found for isoleucyl-tRNA synthetase from yeast, the results of the pyrophosphate exchange studies indicate the possibility of formation of E . Ile-AMP . ATP complexes by random addition of one ATP and one isoleucine molecule, followed by adenylate formation, release of pyrophosphate and subsequent addition of a second molecule of ATP. For the aminoacylation in the absence of pyrophosphatase, a rapid-equilibrium random ter addition of the substrates is found whereas the enzyme from yeast exhibits a steady-state ordered ter-ter mechanism; in the presence of pyrophosphatase the mechanism is bi-uni uni-bi ping-pong similarly as observed for the yeast enzyme. A comparison of inhibition patterns obtained with N(6)-benzyladenosine 5'-triphosphate under different assay conditions (spermine or magnesium ions, addition of pyrophosphatase) indicates that even more than two pathways of the aminoacylation may exist. The catalytic cycles of the two mechanisms derived from the observed orders of substrate addition and product release include the same enzyme substrate complex (E . tRNA . Ile-AMP) for the aminoacyl transfer reaction. The kcat values, however, are considerably different: kcat of the sequential pathway is about 40% lower than kcat of the ping-pong mechanism.

Adenosine Triphosphate↗

Efficacy of a feed-additive antibacterial combination for improving feedlot cattle performance and health.

The effectiveness of a feed-additive antimicrobial combination for improving feedlot performance and health was tested using 4325 high-risk feeder calves randomly allocated to a control group or an experimental group. The experimental group received the conventional ration plus a feed additive containing 700 mg per head/day of chlortetracycline and sulfamethazine from arrival at the feedlot to day 56 of the feeding period. The inclusion of the feed additive to the ration significantly improved average daily gain for days 0-28 (P = 0.0163) and 0-56 (P = 0.0001), and the feed conversion for days 0-28 (P = 0.0061) and 0-56 (P = 0.0004). Additionally, the use of the feed additive significantly reduced the rate of bovine respiratory disease morbidity for days 0-28 (P = 0.0014) and 0-56 (P = 0.0001), the rate of relapses and mortality for days 0-56 (P = 0.0151 and P = 0.0209, respectively), and the rate of animals diagnosed with chronic respiratory disease for days 0-28 and 0-56 (P = 0.0009 and P = 0.0002, respectively). Performance and health improvements produced by the use of the feed additive were cost-effective.

Animal Feed↗

Malignant melanoma and other second cutaneous malignancies in cutaneous T-cell lymphoma. The influence of additional therapy after total skin electron beam radiation.

BACKGROUND: Previous large studies have shown that patients with cutaneous T-cell lymphoma are at increased risk for basal cell carcinoma and squamous cell carcinoma, and anecdotal case reports have suggested an association with malignant melanoma. It has been postulated that the exposure of cutaneous structures to potentially carcinogenic therapies, such as ionizing radiation or alkylating agents, might be causally associated with the development of these second cutaneous malignancies, but, to date, no study has directly addressed this issue. The purpose of this study was to evaluate the occurrence of second cutaneous malignancies in a group of patients with cutaneous T-cell lymphoma treated with total skin electron beam therapy and to examine the additional effects of oral psoralen with UV-A phototherapy, topical mechlorethamine hydrochloride therapy, and further radiation therapy. One hundred sixty-four patients with cutaneous T-cell lymphoma who had received total skin electron beam therapy between 1974 and 1990 were identified, and information was abstracted from their records. RESULTS: Six patients developed malignant melanoma 12 to 95 months after total skin electron beam therapy. Of the six patients, three had received oral psoralen with UV-A as additional therapy and two had received topical mechlorethamine. None had received additional radiation therapy. Twenty-four patients developed more than 37 basal cell carcinomas and 34 squamous cell carcinomas from 11 months to more than 10 years after total skin electron beam therapy. Of the 24 patients, 15 had received oral psoralen with UV-A and 12 had received mechlorethamine as additional therapy. Additional radiation therapy had been administered to nine patients. During a median follow-up of 6 years, no patients died of any second cutaneous malignancy. CONCLUSION: We found a high rate of both melanoma and nonmelanoma skin cancer. The additional use of mechlorethamine or oral psoralen plus UV-A, but not radiation, was significantly associated with the development of basal cell carcinoma and squamous cell carcinoma, but not malignant melanoma.

Adult↗

[Clinical significance of additional ST segment elevation immediately after successful reperfusion in patients with anterior wall acute myocardial infarction].

The clinical significance of additional ST segment elevation immediately after reperfusion in acute myocardial infarction (AMI) is still unclear. The influence of additional ST elevation on myocardial damage was examined in 62 patients with first anterior AMI. All patients had coronary reflow (thrombolysis in myocardial infarction: TIMI grade III) within 6 hours after the onset of infarction and no subsequent reocclusion for at least 14 days. The patients were classified into two groups: group ST (+), 26 patients with additional ST elevation (> or = 5 mm increase in sigma ST in lead V1-V6) immediately after reperfusion, and group ST(-), 36 patients without additional ST elevation. Myocardial damage was estimated by the number of abnormal Q wave before and 1 hour after reperfusion (nQpre and nQpost. There were no significant differences in the elapsed time, ECG indexes before reperfusion and regional wall motion (RWM: SD/chord; SD = standard deviation) in the acute phase and 14 days after the onset between the two groups. Moreover, within each group the patients were classified into two groups on the basis of RWM 14 days after the onset: group A = RWM < -2.5 in group ST (+) (n = 17); group B = RWM > or = -2.5 in group ST(+) (n = 9); group C = RWM < -2.5 in group ST (-) (n = 14); group D = RWM > or = -2.5 in group ST(-) (n = 22). There were no significant differences in the elapsed time between the four groups. nQpre was highest in group C and was lowest in group D (group A: 2.1, group B: 1.9, group C: 4.1, group D: 1.4), and nQpost was highest in group C and group A, and was lowest in group D (group A: 4.1, group B: 2.7, group C: 4.4, group D: 2.0). There was a significant increase in nQ after reperfusion (nQpost-nQpre) in group A and group B, which was greater in group A than in group B. The increase in sigma ST after reperfusion was greater in group A than in group B. There was no significant increase in nQ after reperfusion in group C and in group D, and both nQpre and nQpost were highest in group C, and lowest in group D. Infarct size was larger in group A and in group C than group B and group D, and there was no significant improvement in RWM in group A and in group C. In conclusion, additional ST elevation immediately after reperfusion seems to occur in patients with not so severe myocardial damage before reperfusion, and may reflect reperfusion injury. Additional ST elevation is not observed in patients with preceding extensive myocardial damage which may be irreversible or not still advanced at the time of reperfusion.

Adult↗

Evaluation of certain food additives and contaminants.

This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives and contaminants, with a view to recommending Acceptable Daily Intakes (ADIs) for humans, and to prepare specifications for the identity and purity of food additives. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of food additives and contaminants (including flavouring agents), assessments of the intake of contaminants, and the establishment and revision of specifications. A summary follows of the Committee's evaluations of toxicological data on various specific food additives (hydrogenated poly-1-decene, erythritol, curdlan, gamma-cyclodextrin and sodium sulfate), substances used in food fortification (sodium iron EDTA), flavouring agents, peanut oil, soya bean oil and contaminants (lead, methylmercury and zearalenone). Annexed to the report are tables summarizing the Committee's recommendations for ADIs of the food additives and substance used in food fortification considered, changes in the status of specifications for these substances and specific flavouring agents, further information required and the report of an ad hoc Panel on Food Allergens.

Food Additives↗

Food additives (natural and synthetic).

Food additives can be divided into the following categories: intentional, unintentional, contaminants, and those resulting from food processing procedures. Representative food additives from each category are discussed, with special attention being paid to the status of those suspected or proven to be toxic to humans. In addition, certain chemical components of food and methods for testing food additives are considered. Areas requiring additional testing include saccharin, cooking procedures, especially charcoal broiling, and hydrozines in mushrooms. The more recent developments in test procedures, including in vitro test methods, the transplacental exposure route, the use of maximal tolerated dose, and the initiation--promotion sequence, are evaluated.

Animals↗

Food additives and contaminants. An update.

Food additives continue to be a source of benefits to the consuming public but there are also perceived risks. Concern for the latter in the last decade has produced a society afflicted with cancer phobia. The intentional additives including sugars, salt, corn syrup, and dextrose make up 90% of the direct additives. These, along with a limited number of familiar items make up a large proportion of the remainder of the additives. Such common ingredients as nitrates and nitrites, solanine, cyanogenetic compounds, arsenic, etc., are unavoidably consumed in the diet and with little if any evidence for public health consequences. Major concern on the part of the public in recent years has been focused on man-made chemicals which are intentionally added to foods to enhance flavors and acceptability, nutrient value, shelf life and increased availability. These include food colors, nonnutritive and low-nutrient sweeteners, (saccharin, cyclamate, aspartame); antioxidants; and nitrites. Contaminants, sometimes incorrectly included in lists of food additives, present the greatest potential threat to public health. Such contaminants as mycotoxins, nitrosamines, polychlorinated biphenyls (PCBs), pesticides, among others, provide a continuing challenge to our regulatory agencies and to public health authorities. Evidence to date indicate that these responsible for food safety are doing an admirable job, and as a society, our food supply has never been better, or safer, and, as a population, we have never been healthier. Aside from contaminants, major concerns relate to an excess of good food and to obesity. These comments should not be taken to infer that we should relax our concern and surveillance; instead more concern and surveillance should be exerted toward those uncontrolled substances such as natural plant products and alleged natural nutrients, roots, herbs, etc., which are given much credit for positive health effects, without meeting the high standards of our legitimate food industry.

Animals↗

How many food additives are rodent carcinogens?

One generally assumes that chemical agents added to foods are reasonably free of risks to human health, and practically everyone consumes some additives in his or her food daily throughout life. In the United States, the 1958 Food Additives Amendment to the Federal Food, Drug and Cosmetic Act of 1938 requires food manufacturers to demonstrate the safety of food additives to the Food and Drug Administration (FDA). The Amendment contains a provision that prohibits approval of an additive if it is found to cause cancer in humans or animals. In the present study, data from the National Toxicology Program rodent bioassay (NTPRB) were used to identify a sample of approximately 50 rodent-tested additives and other chemicals added to food that had been evaluated independently of the FDA/food industry. Surprisingly, the sample shows more than 40% of these food chemicals to be carcinogenic in one or more rodent groups. If this percentage is extrapolated to all substances added to food in the United States, it would imply that more than 1000 of such substances are potential rodent carcinogens. The NTP and FDA test guidelines use similar, though not necessarily identical, rodent test procedures, including near lifetime exposures to the maximum tolerated dose. The FDA specifies that test chemicals should be administered by the oral route. However, the oral route includes three methods of delivering chemicals, that is, mixed in the food or water or delivered by stomach tube (gavage). The NTP data show only 1 of 18 food chemicals mixed in the food are rodent carcinogens, but 16 of 23 gavage-administered food chemicals are carcinogenic to rodents. The distribution suggests that among orally delivered chemicals, those administered in the feed will more likely prove to be noncarcinogens than chemicals given by gavage. The rodent data also reveal that effects may vary according to dose and genotype, as well as by route of administration, to further complicate extrapolation to humans. Human experience with known carcinogens such as tobacco, asbestos, and benzidine convinces us that environmental carcinogens constitute a real threat to human health, although predicting human carcinogens from rodent tests involves a number of uncertainties. These uncertainties do not mean that we should simply ignore the presence of carcinogens. Rather, in the interests of public safety, a serious effort should be made to resolve the questions surrounding the presence of chemicals identified as rodent carcinogens in our food. Environ. Mol. Mutagen. 39:69-80, 2002 Published 2002 Wiley-Liss, Inc.

Animals↗