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PubMed1977

Availability of oxidized sulfur amino acids for the growing chick.

In four trials, experimental diets were fed to one week old broiler cockerels for a period of 14 days to compare the availability of oxidized sulfur amino acids to DL-methionine on an equimolar basis. The data were analyzed by the slope-ratio technique. Chick weight gain per unit feed consumed was the dependent variable and dietary level of supplemental amino acid was the independent variable. There was no significant (P=.05) differences in availability of DL-, L-, and D-methionine. D-, DL-, and L-methionine sulfoxide were 52, 59 and 77%, respectively, as available as DL-methionine. The differences in availability between the three sulfoxides and DL-methionine were significant. Both DL- and D-methionine sulfoxide were significantly less available than L-methionine sulfoxide. No response was obtained from L-cysteic acid or DL-methionine sulfone.

Amino Acids, Sulfur↗

PubMed1992

The role of availability in the estimation of national populations.

In two parallel experiments, conducted 17 months apart, we examined the relations among population estimates, availability, and media coverage of the 100 countries with populations of 4 million or more. The results were consistent with the main hypothesis, that availability influences population estimates. Specifically, we found that (1) rated knowledge of each country (our measure of availability) was strongly correlated with estimated population for that country; (2) rated knowledge was more strongly correlated with estimated population than were other plausible predictors, such as land area; (3) a strong partial correlation between rated knowledge and estimated population remained even after true population and true land area were partialed out; and (4) longitudinal changes in rated knowledge predicted longitudinal changes in estimated population. Also as hypothesized, media coverage was positively related to availability and to population estimates. Further, we found that population estimates, rated knowledge, and amount of media coverage that each country received were very stable over the year-and-a-half period. These results led us to consider when availability is most likely to be relied upon heavily in quantitative estimation and how it may be integrated with other knowledge to derive quantitative estimates.

Adult↗

PubMedDate not supplied

Clinical comparison of the anticalculus efficacy of three commercially available dentifrices.

A three-month, double-blind, parallel and unsupervised clinical study was conducted to compare the effects on supragingival calculus formation of the following four dentifrices: 1) A placebo dentifrice containing 0.243% sodium fluoride in a silica base. 2) A commercially available anticalculus dentifrice containing 5.0% soluble pyrophosphate in a 0.243% sodium fluoride silica base. 3) A commercially available anticalculus dentifrice containing 1.3% soluble pyrophosphate and 1.5% of a Gantrez copolymer in a 0.243% sodium fluoride silica base. 4) A commercially available anticalculus dentifrice containing 3.3% soluble pyrophosphate and 1.0% of a Gantrez copolymer in a 0.243% sodium fluoride silica base. The three-month results indicated that the three commercially available anticalculus dentifrices provided statistically significant reductions (at the 99% level of confidence) in supragingival calculus formation of 43.87%, 46.60%, and 51.32% respectively, as compared to the placebo dentifrice. There was no statistically significant difference among the three commercially available anticalculus dentifrices.

Adult↗

PubMed1988

Estimating reduced availability due to first pass elimination from relative total clearance and renal clearance.

A simple formula is presented for estimating the systemic availability of an orally administered drug from the relative total clearance (oral clearance) when renal clearance forms an important part of total clearance. Hepatic plasma flow is used in the equation and is represented by an average value taken from the literature. The formula is applied to data for cimetidine discussed in the literature. A further application is demonstrated for a drug under development for which an intravenous formulation was not available. It is possible to estimate the upper and lower limit of availability if some information on the amount of drug absorbed is available.

Administration, Oral↗

PubMed1991

Extent of damage to amino acid availability of whey protein heated with sugar.

The effect of heat treatments, at various water activities (aW), on digestibility and on the availabilities of amino acids of whey protein samples in the presence of lactose was estimated by an in vitro digestion method with continuous dialysis. Four aW (0.3, 0.5, 0.7 and 0.97), three temperatures (75, 100 and 121 degrees C) and three heating periods (50, 500 and 5000 s) were selected. The initial lysine:lactose molar ratio was 1:1. Amino acid profiles showed that excessive heating of whey (121 degrees C, 5000 s) destroyed a significant proportion of cystine at all aW, lysine at aW 0.3, 0.5 and 0.7, and arginine at aW 0.5 and 0.7. At aW 0.3, 0.5 and 0.7, protein digestibility decreased (P less than 0.05) as the temperature increased from 75 to 121 degrees C for a heating period of 5000 s, and as the heating time was prolonged, from 500 to 5000 s at 121 degrees C. Excessive heating also decreased (P less than 0.05) the availabilities of all amino acids at aW 0.3, 0.5 and 0.7. The availabilities of lysine, proline, aspartic acid, glutamic acid, threonine, alanine, glycine and serine were particularly affected. Severe heating at aW 0.97 did not seem to favour the Maillard reaction, but the availabilities of cystine, tyrosine and arginine were decreased, probably as a result of structural modifications of the protein upon heating. Heating whey protein concentrates in the presence of lactose not only affected lysine, but also impaired enzymic liberation of other amino acids, according to the severity of heat treatments and aW.

Amino Acids↗

PubMed1992

The effect of dairy products on iron availability.

Many researchers report substantial reductions in iron availability when dairy products are consumed with solutions of iron. Yet other studies indicate that dairy products have little effect on iron availability when added to complex meals. The conflicting data may be due to differences in the technique used to measure availability, species of animal used, form of iron in the diet, and meal composition. Human studies show superior bioavailability of iron in human milk when compared with cow's milk. Definitive causes for the differences between human and cow's milk have not been identified. Human milk contains lower amounts of casein, phosphate, and calcium, components thought to inhibit iron absorption. More work is needed to identify the factors that influence iron-dairy interactions. The nutritional benefits provided by dairy products outweigh the slight inhibitory effect they may have on iron availability.

Animals↗

PubMed1988

Bioavailability of amino acids in plant feedstuffs determined by in vitro digestion, chick growth assay, and true amino acid availability methods.

An in vitro, pepsin-pancreatin digestibility method was used to estimate the bioavailabilities of amino acids in plant feedstuffs, including two cultivars of four cereal grains and three high-protein feedstuffs. As a technique for separating hydrolytic products from substrate, trichloroacetic acid (TCA) was compared with three ultrafiltration techniques. Solutions were filtered continuously by a membrane of 500-Dalton pore size (cUF) and terminally by membranes of 500 Dalton (tUF) and 10,000 Dalton (CX). Additionally, bioavailability of amino acids was determined in vivo by the true amino acid availability (TAAA) method and utilization of lysine was determined by chick growth assay (CGA). Correlations of in vitro and in vivo estimates of availabilities were ranked CX = cUF greater than tUF greater than TCA for total amino acids and were ranked similarly for most individual amino acids. When determined using the superior technique, correlation between in vitro digestibilities of amino acids and TAAA were moderately high for the combined cereal grains (r = .92), were lower when data included wheat middlings (r = .90), but were unreliable when data included soybean meal and corn gluten meal (r = .29). Prediction of CGA values from in vitro digestibility was less reliable (r = .42) than that using TAAA values. There was agreement between values for lysine availability when determined for six grain samples by CGA and TAAA (r = .79). Evaluation from the correlations of the in vitro with the in vivo estimates of availabilities indicated that terminal filtration by a membrane of medium pore size (10,000 Dalton) or continuous filtration by a membrane of very low pore size (500 Dalton) made separations superior to those of terminal filtration (500 Dalton) and TCA precipitation.

Amino Acids↗

PubMed1977

The bio-availability of beta-acetyldigoxine (Novodigal) alone and combined with oxyfedrine (Ildamen-Novodigal).

The bio-availability of various galenic preparations of beta-acetyldigoxine was tested in six healthy probands after a single oral dose (1 mg). The availability parameters were calculated from the areas under the plasma concentration curves and from the cumulative urinal excretion. There was no significant difference between the bio-availabilities of Novodigal (beta-acetyledigoxine tablets), Ildamen-Novodigal (beta-acetyldigoxine and oxyfedrine) and an alcoholic solution of beta-acetyldigoxine. Correlation calculations showed that the determination of the plasma concentration courses up to six hours after substance application are most favourite in regard to judging the absorption processes of digoxine preparations. For the assessment of the bio-availability, the methods of comparing the areas under the blood level curves of 0 to 6 hrs and of comparing the cumulative urinal excretion over a period of 24 hrs were of equal validity.

Adult↗

PubMed1991

Slide presentation graphics using a personal computer. A comparative evaluation of available software.

Most of the available methods for preparing professional slides to be used in oral presentations can be cumbersome, time-consuming, and expensive. Creating high-quality 35-mm slides may require the use of expensive medical illustrators and photographic equipment not available to all physicians. More recently, technology has emerged that permits professional in-office generation of quality slides using commercially available computer graphics software and film recorders. Such a system is simple to establish and maintain when compared with commercial slide production facilities. We will review the hardware requirements of such a system, as well as the advantages and disadvantages of several commercially available software packages. Using a personal computer-based slide-making system, any physician communicating with small or large groups of people can now produce professional-looking slides easily, rapidly, and inexpensively.

Audiovisual Aids↗

PubMed1987

Patterns of calling time and ipecac availability among poison center callers.

Over a one-month period all telephone calls from the public (n = 3828) to a regional poison center were analyzed. The proportion of early calls (within ten minutes of exposure) decreased with age. Late calls (greater than 30 minutes) were significantly associated with higher hospital referral rates when compared with earlier calls in children younger than 5 years (4.6% vs 1.8%) and adults (33% vs 15%). Ipecac was available in 59% of the homes of callers with children younger than 5 years. Hospital referrals were significantly less common among children who had ipecac at home (1%) compared with children who did not (3%). While the availability of ipecac was similar among callers and a matched sample of households who previously called the poison center (58%), ipecac was much less frequently available (24%) among households whose members had not previously called the center. These data infer that educating the public to call the poison center promptly may result in reduction of hospital referrals. Poison education efforts should be targeted to populations with low ipecac availability and low utilization of the poison center.

Adolescent↗

PubMed1992

Body measurements, estrogen availability and the risk of human breast cancer: a case-control study.

Recent studies on lifestyle-related mechanisms involved in cardiovascular risk offer important clues for a better understanding of breast-cancer epidemiology. Central body-fat distribution promoted by an affluent dietary intake and a sedentary lifestyle over many years is related to elevated serum triglycerides and free fatty acids, with lower levels of sex-hormone-binding globulin (SHBG). The resulting greater availability of estradiol not bound to SHBG could help to explain the high breast-cancer incidence in Western industrialized countries. We conducted a case-control study comparing 225 women aged 38 to 75 years with operable (stage I or II) breast cancer and 441 women of the same age having no breast cancer who participated in a population-based breast-cancer screening program. Body fatness, as measured by body mass index (BMI), fat distribution as measured by waist-to-hip girth ratio (WHR), body height, serum lipids, SHBG and the available fraction of estradiol were analyzed in a conditional logistic regression, together with family history for breast cancer, reproductive history and smoking. Post-menopausal cases showed no difference in body fatness (BMI), but a significant preponderance of central adiposity (WHR). In contrast, pre-menopausal cases were significantly leaner, but had a similar body-fat distribution as compared with controls. In all women, WHR, and less strongly BMI, was positively correlated with serum levels of triglycerides and available estradiol fractions. An independent, positive linear correlation between body height and relative risk (RR) was observed. Moreover, a significant correlation between SHBG and menarcheal age was seen in cases, but not in controls. These data support our hypothesis that lifestyle relates to breast-cancer risk by metabolic-endocrine mechanisms which modulate the availability of individual sex-steroid concentrations in plasma. The findings of height as a risk factor and adult SHBG levels being correlated with menarcheal age suggest that lifestyle factors promoting breast-cancer development already act around puberty. The leanness of pre-menopausal cases awaits further explanation.

Adult↗

PubMed1989

Availability and timing of new drugs in Israel: analysis and international comparison.

Whereas the latest data suggest that the number of new chemical entities (NCE) launches worldwide may be on the increase, both recent and longer term data show a decline in the rate of NCE introductions into Israel. In terms of percentage availability, only 30% of NCEs available worldwide during 1978-1987 were introduced in Israel during the same period, compared with 42% for the U.S.A. In both countries there has been a decreasing percentage availability since 1983/84. The percentage availability of commercially significant NCEs was greater (47%) compared to all NCEs introduced in Israel. Whereas in the U.S.A. the lower the therapeutic rating the higher the proportion of NCEs, in Israel the B- and C-rated drugs were equally represented. NCEs with an A-rating had a similar share of all NCEs (ca 15%) in both countries. The average time lag for NCEs launched worldwide to reach Israel during 1978-1987 was 4 to 5 years, but in recent years there has been a considerable decline. Commercially significant NCEs introduced in Israel had on average a shorter time lag of 0.5 years than the average for all NCEs introduced. In spite of a preponderance of NCEs first launched in the U.S.A. there was on average a slight relative lag into the U.S.A. compared to Israel. This was probably due to there being a number of NCEs first introduced in Israel with a long delay before they were subsequently approved in the U.S.A.(ABSTRACT TRUNCATED AT 250 WORDS)

Drugs, Investigational↗

PubMed1989

Triiodothyronine bound to red blood cells is not available for transport through the blood-brain barrier.

Many steroid and thyroid hormones and some drugs are bound by circulating red cells. Red cell-bound ligand may not be physiologically inert, as recent studies show that red cell-bound drug is available for uptake by brain. To investigate whether triiodothyronine (T3) is available for uptake by brain in vivo from the circulating red cell pool, the present investigations measure the effects of human erythrocytes on rat brain uptake of [125I]T3 in vivo. The fraction of circulating T3 available for uptake in vivo in the presence of 0, 2, 5, 10, 22, or 44% red cells was essentially identical to the fraction of [125I]T3 unbound in vitro. Therefore, [125I]T3 bound to red cells obtained from normal volunteers is not available for uptake by brain in vivo.

Adult↗

PubMed1991

[Content of available lysine in gamma-irradiated soybean products].

The content in available lysine of soya protein products irradiated in a 60Co-gamma cell were investigated. The results indicate that available lysine content and crude protein content at irradiation doses of 1, 3 and 5 kGy were unaffected at the 95% significance level. During 3-month storage the irradiated samples showed no significant (p = 0,05) changes of available lysine content. In samples with high content of lecithin, which were irradiated at 1 kGy as well as non-irradiated the content of available lysine was significantly (p = 0,05) reduced after 8-month storage; the other products as well as the at 3 and 5 kGy irradiated samples showed no significant decrease. Immediately after irradiation the microflora was significantly (p = 0,05) reduced. Under the effect of radiation treatment at 3 and 5 kGy the microflora was reduced to nearly 100% after 3-month storage.

Bacteria↗

PubMed1979

Plasma amino acid response to single test meals in humans. VI. Determination of available lysine.

The plasma amino acid response to single test meals in young adults was used to determine the amount of physiologically available lysine in heat-treated milk samples. The plasma amino acid responses were evaluated as PAA ratios according to a modified calculation procedure based on the method proposed by Longenecker and Hause. The amount of available lysine was determined by two separate series of single-meal tests. In the first, a relationship was established between the plasma amino acid response (PAA ratio) and the dietary level of lysine (given as synthetic amino acid mixtures). This relationship could be described by linear regression (r = 0.90). This regression line was then used to quantitatively evaluate the lysine PAA ratios obtained from single test meals with heat-treated milk samples. The heat-treatment of the milk samples caused a marked reduction of the amount of physiologically available lysine. The quantitative estimates obtained by the present plasma amino acid technique were in good agreement with determinations of available lysine in the same milk samples based on rat bioassay and chemical analysis.

Adult↗

PubMedDate not supplied

Impact of the availability of a prior electrocardiogram on the triage of the patient with acute chest pain.

STUDY OBJECTIVE: To determine whether information from a prior electrocardiogram (ECG) improves diagnostic accuracy in the emergency department (ED) evaluation of patients with acute chest pain. DESIGN: Analysis of prospectively collected data from a cohort study. SETTING: Emergency departments of four community and three university hospitals. PATIENTS: 5,673 patients aged greater than or equal to 30 years who presented to the EDs of participating hospitals for evaluation of acute chest pain, including 772 (14%) with acute myocardial infarction (AMI). MEASUREMENTS AND MAIN RESULTS: After adjusting for clinical characteristics, no significant difference was found in the sensitivities of admission to the hospital or to the coronary care unit (CCU) between AMI patients with and without prior ECGs available for review. However, non-AMI patients with prior ECGs available for review were more likely to avoid CCU admission than were non-AMI patients without prior ECGs. This improvement in specificity was most marked in the 2,024 patients whose current ED ECGs had changes consistent with ischemia or infarction: when a prior ECG was available, non-AMI patients were more than twice as likely to be discharged (26% vs. 12%) and about 1.5 times as likely to avoid CCU admission (39% vs. 27%) (both p less than 0.0001). Admission rates of AMI patients with and without prior ECGs were similar. CONCLUSION: When the current ECG is consistent with ischemia or infarction, the availability of a prior ECG for comparison to determine whether the ECG changes are old or new improves diagnostic accuracy and triage decisions by reducing the admission of patients without AMI or acute ischemic heart disease (increased specificity) without reducing the admission of patients with these diagnoses (unchanged sensitivity).

Aged↗

PubMed1976

The effect of ribose 5-phosphate and 5-phosphoribosyl-1-pyrophosphate availability on de novo synthesis of purine nucleotides in rat liver slices.

The effect of increasing cellular ribose 5-phosphate (ribose-5-P) availability by methylene blue-induced acceleration of the oxidative pentose phosphate pathway on the rate of 5-phosphoribosyl-1-pyrophosphate (P-ribose-PP) generation, was studied in slices of rat liver at varying Pi concentration. It was found that at Pi concentration prevailing in the tissue of extracellular physiological Pi concentration, ribose-5-P availability is saturating for P-ribose-PP generation, as gauged by the rate of adenine incorporation into tissue nucleotides. The effect of altering P-ribose-PP availability on the rate of de novo purine production gauged by the rate of formate incorporation into purines, was also studied. It was found that the physiological P-ribose-PP concentration in rat liver tissue is limiting for purine synthesis de novo. Depletion of cellular P-ribose-PP, achieved by increase of P-ribose-PP consumption, decelerated purine synthesis, while increase of P-ribose-PP availability, achieved by activation of P-ribose-PP synthetase occurring at elevated Pi concentration, resulted in acceleration of purine synthesis.

Animals↗

PubMed1990

Inhibition patterns and seasonal availability of nematodes for beef cattle grazing on Argentina's western Pampas.

The seasonal population trends of cattle nematodes in tracer calves are described from 1981 to 1987. Successive worm-free calves were grazed with growing beef cattle for 20-30 days at 6 week intervals and then slaughtered for nematode counts 2 weeks after their removal from pasture. Ostertagia, Cooperia, Trichostrongylus and Haemonchus were the main genera recovered. O. ostertagi was the most often found and acquisition of inhibition-prone larvae began in late winter and reached a peak in spring, while maximum larval availability was in autumn. The seasonal inhibition and larval availability pattern for T. axei was similar to that of Ostertagia. Cooperia showed greatest inhibition during winter with maximum larval availability in autumn and spring. Haemonchus was more prevalent during summer to early autumn and no inhibition was observed. It was concluded that infective larval availability for tracer calves was highest during autumn, and most reduced in summer. All predominant species were able to survive over summer on pasture.

Animals↗