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1

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Human Interindividual Variability in Parameters Related to Health Risks (1999)

Hattis, Dale ; Banati, Prerna ; Goble, Rob ; [et al.]

Springer

Risk analysis 19 (1999), S. 711-726

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ISSN: 1539-6924

Keywords: variability ; exposure ; susceptibility ; risk assessment ; pharmacokinetics ; pharmacodynamics

Source: Springer Online Journal Archives 1860-2000

Topics: Energy, Environment Protection, Nuclear Power Engineering

Notes: Abstract This paper reviews existing data on the variability in parameters relevant for health risk analyses. We cover both exposure-related parameters and parameters related to individual susceptibility to toxicity. The toxicity/susceptibility data base under construction is part of a longer term research effort to lay the groundwork for quantitative distributional analyses of non-cancer toxic risks. These data are broken down into a variety of parameter types that encompass different portions of the pathway from external exposure to the production of biological responses. The discrete steps in this pathway, as we now conceive them, are: •Contact Rate (Breathing rates per body weight; fish consumption per body weight) •Uptake or Absorption as a Fraction of Intake or Contact Rate •General Systemic Availability Net of First Pass Elimination and Dilution via Distribution Volume (e.g., initial blood concentration per mg/kg of uptake) •Systemic Elimination (half life or clearance) •Active Site Concentration per Systemic Blood or Plasma Concentration •Physiological Parameter Change per Active Site Concentration (expressed as the dose required to make a given percentage change in different people, or the dose required to achieve some proportion of an individual's maximum response to the drug or toxicant) •Functional Reserve Capacity–Change in Baseline Physiological Parameter Needed to Produce a Biological Response or Pass a Criterion of Abnormal Function Comparison of the amounts of variability observed for the different parameter types suggests that appreciable variability is associated with the final step in the process–differences among people in “functional reserve capacity.” This has the implication that relevant information for estimating effective toxic susceptibility distributions may be gleaned by direct studies of the population distributions of key physiological parameters in people that are not exposed to the environmental and occupational toxicants that are thought to perturb those parameters. This is illustrated with some recent observations of the population distributions of Low Density Lipoprotein Cholesterol from the second and third National Health and Nutrition Examination Surveys.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1007045922532

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2

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Evaluation of the Uncertainty in an Oral Reference Dose for Methylmercury Due to Interindividual Variability in Pharmacokinetics (1999)

Clewell, Harvey J. ; Gearhart, Jeffery M. ; Gentry, P. Robinan ; [et al.]

Springer

Risk analysis 19 (1999), S. 547-558

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ISSN: 1539-6924

Keywords: MeHg ; pharmacokinetics ; PBPK model ; variability ; risk assessment

Source: Springer Online Journal Archives 1860-2000

Topics: Energy, Environment Protection, Nuclear Power Engineering

Notes: Abstract An analysis of the uncertainty in guidelines for the ingestion of methylmercury (MeHg) due to human pharmacokinetic variability was conducted using a physiologically based pharmacokinetic (PBPK) model that describes MeHg kinetics in the pregnant human and fetus. Two alternative derivations of an ingestion guideline for MeHg were considered: the U.S. Environmental Protection Agency reference dose (RfD) of 0.1 μg/kg/day derived from studies of an Iraqi grain poisoning episode, and the Agency for Toxic Substances and Disease Registry chronic oral minimal risk level (MRL) of 0.5 μg/kg/day based on studies of a fish-eating population in the Seychelles Islands. Calculation of an ingestion guideline for MeHg from either of these epidemiological studies requires calculation of a dose conversion factor (DCF) relating a hair mercury concentration to a chronic MeHg ingestion rate. To evaluate the uncertainty in this DCF across the population of U.S. women of child-bearing age, Monte Carlo analyses were performed in which distributions for each of the parameters in the PBPK model were randomly sampled 1000 times. The 1st and 5th percentiles of the resulting distribution of DCFs were a factor of 1.8 and 1.5 below the median, respectively. This estimate of variability is consistent with, but somewhat less than, previous analyses performed with empirical, one-compartment pharmacokinetic models. The use of a consistent factor in both guidelines of 1.5 for pharmacokinetic variability in the DCF, and keeping all other aspects of the derivations unchanged, would result in an RfD of 0.2 μg/kg/day and an MRL of 0.3 μg/kg/day.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1007017116171

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3

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Enzymatic and pharmacokinetic studies on the metabolism of branched chain α-keto acids in the rat (1983)

Bässler, K. H. ; Pietrek, Astrid

Springer

European journal of nutrition 22 (1983), S. 14-26

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ISSN: 1436-6215

Keywords: branched chain α-keto acids ; 4-methyl-2-oxopentanoate, 3-methyl-2-oxopentanoate ; 3-methyl-2-oxobutyrate ; dehydrogenation ; transamination ; pharmacokinetics ; absorption

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine

Description / Table of Contents: Zusammenfassung Michaelis-Konstanten und Aktivitäten von Dehydrogenasen und Transaminasen der drei verzweigten α-Ketosäuren Keto-Valin, Keto-Leucin und Keto-Isoleucin in Leber, Niere, Skeletmuskel und Gehirn von Ratten werden mitgeteilt. Nach oraler Zufuhr passieren nur 11–22% der Ketosäuren unverändert die Leber. Aus pharmakokinetischen und Resorptions-Untersuchungen erhaltene Blutspiegel an Ketosäuren werden zu den Michaelis-Konstanten in Beziehung gesetzt. Bei den geringen Konzentrationen an Ketosäuren nach oraler Zufuhr kann angenommen werden, daß die oxidativen Prozesse in den nichthepatischen Geweben über die Transaminierung überwiegen. Daten über die Wachstumseffizienz von verzweigtkettigen α-Ketosäuren im Vergleich zu den entsprechenden Aminosäuren stimmen mit dieser Vorstellung überein. Bei intravenöser Verabreichung müßten die Voraussetzungen für Transaminierung besser sein als nach oraler Zufuhr. Auf der Basis von Daten aus der Literatur werden die Übertragbarkeit unserer Befunde auf den Menschen und die verschiedenen Faktoren, welche die Effizienz der verzweigten α-Ketosäuren durch Einwirkung auf ihren Stoffwechsel beeinflussen können, diskutiert.

Notes: Summary Miehaelis-constants and enzyme activities for dehydrogenation and transamination of the three branched chainα-keto acids in liver, kidney, skeletal muscle, and brain of rats are reported. After oral load only 11–22 % of the keto acids pass the liver unchanged. Blood levels in pharmacokinetic and absorption studies are related to the Michaelis-constants. At the low keto-acid concentrations after oral application, dehydrogenation in the non-hepatic tissues is supposed to prevail over transamination. Data on feed efficiency of branched chain α-keto acids reported in the literature support this view. The chance for transamination is better after intravenous administration. The transferability of our data to humans, and various factors influencing the efficiency of branched chain α-keto acids are discussed in connection with data reported in the literature.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02020781

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4

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Selektive Partnerwahl der Aaskrähe (Corvus corone) in der Hybridisierungszone von Rabenkrähe (C. c. corone) und Nebelkrähe (C. c. cornix) (1998)

Risch, Markus ; Andersen, Lars

Springer

Journal of ornithology 139 (1998), S. 173-177

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ISSN: 1439-0361

Keywords: mate choice ; taxonomy ; phenotypic hybrids ; fitness ; decision rule

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Description / Table of Contents: Zusammenfassung Die als Unterarten klassifizierten europäischen Formen der Aaskrähe, Rabenkrähe und Nebelkrähe, besiedeln verschiedene, aneinandergrenzende Verbreitungsgebiete und hybridisieren in der Kontaktzone. Die Nachkommen von Mischpaaren sind fruchtbar und können sowohl mit anderen Hybriden als auch mit Raben- und Nebelkrähen erfolgreich brüten. Trotzdem kommt es zu keiner völligen Vermischung der Formen und/oder Verlagerung der Verbreitungsgebiete. Vor diesem Hintergrund untersuchten wir die Partnerwahl von Aaskrähen in der Hybridisierungszone auf der nordfriesischen Insel Amrum und stellten fest, daß Partner gleichen Phänotyps häufiger miteinander verpaart waren, als stochastisch zu erwarten gewesen wäre. Unsere Daten bestätigen vergleichbare Studien aus Hybridisierungszonen in Italien und Sibirien. Wir schließen daraus, daß phänotypisch selektive Partnerwahl bei der Aaskrähe ein allgemeines Phänomen sein könnte und diskutieren, warum dieses Verhalten anfitness-relevante Parameter gekoppelt sein sollte. Um welche es sich dabei handeln könnte, wurde bisher nicht hinreichend untersucht und muß deshalb offen bleiben.

Notes: Summary Carrion Crow and Hooded Crow are regarded as subspecies of the Crow. They show frequent hybridisation along the adjacent borders of their distribution. Mixed pairs produce fertile offspring which are able to breed successfully with both hybrids and mates of either phenotype. However, hybridisation does not lead to phenotypic changes of Carrion and Hooded Crows in general nor in their distinct distribution. We studied the mating behaviour of Crows in the hybrid zone on the Island of Amrum (Schleswig-Holstein, Germany) and found evidence that Crows may prefer mates of the same phenotype. Our data confirm previous studies which reported assortative mating with respect to plumage coloration from hybrid zones in Italy and Siberia. We discuss why this behaviour should be related tofitness traits which in our opinion have not yet been studied adequately nor identified.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01651226

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5

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A Taxonomy of Evolutionary Algorithms in Combinatorial Optimization (1999)

Calégari, Patrice ; Coray, Giovanni ; Hertz, Alain ; [et al.]

Springer

Journal of heuristics 5 (1999), S. 145-158

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ISSN: 1572-9397

Keywords: evolutionary algorithms ; genetic algorithms ; taxonomy

Source: Springer Online Journal Archives 1860-2000

Topics: Mathematics

Notes: Abstract This paper shows how evolutionary algorithms can be described in a concise, yet comprehensive and accurate way. A classification scheme is introduced and presented in a tabular form called TEA (Table of Evolutionary Algorithms). It distinguishes between different classes of evolutionary algorithms (e.g., genetic algorithms, ant systems) by enumerating the fundamental ingredients of each of these algorithms. At the end, possible uses of the TEA are illustrated on classical evolutionary algorithms.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1009625526657

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6

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Growth response of lentil and wheat to Glomus clarum NT4 over a range of P levels in a Saskatchewan soil containing indigenous AM fungi (1997)

Xavier, Lisette J. C. ; Germida, J. J.

Springer

Mycorrhiza 7 (1997), S. 3-8

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ISSN: 1432-1890

Keywords: Key words Glomus clarum NT4 ; Lentil ; Wheat ; Indigenous AMF ; Phosphorus

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract The growth responses of lentil (Lens esculenta L. cv. Laird) and two wheat cultivars (Triticum aestivum L. cv. Laura and Neepawa) to Glomus clarum NT4 in soil containing indigenous arbuscular mycorrhizal fungi (AMF) and fertilized with phosphorus at different (0, 5, 10, 20 ppm) levels was studied in a growth chamber. Soil was inoculated with a monospecific culture of G. clarum NT4 to provide an inoculant:indigenous AMF ratio of ca. 1 : 100. The shoot and root growth, and AMF colonization levels of NT4-inoculated lentil were significantly (P≤0.05) greater than the appropriate control plants in the unfertilized soil at 48 days after planting (DAP). At 95 DAP, NT4 inoculation had significantly increased the shoot dry weight (P≤0.08) and AMF colonization (P≤0.05) of lentil plants receiving 5 mg P kg–1 soil, whereas 20 mg P kg–1 soil reduced the shoot growth of NT4-inoculated plants. The NT4 inoculant had no effect (P≤0.05) on shoot P content, but increased (P≤0.08) the P-use efficiency of lentil plants receiving 5 mg P kg–1 soil. In contrast to the inoculant's effect on lentil, NT4 generally had no positive effect on any of the parameters assessed for wheat cv. Laura at any P level at 48 or 95 DAP. Similarly, there was no positive effect of NT4 on shoot or root growth, or AMF colonization of wheat cv. Neepawa plants at any P level at 48 DAP. However, NT4 inoculation increased the grain yield of Neepawa by 20% (P≤0.05) when fertilized with 20 mg P kg–1 soil. This yield increase was associated with a significant (P≤0.05) reduction in root biomass and a significant (P≤0.05) increase in the grain P content of inoculated plants. Thus, NT4 appears to have a preference for the Neepawa cultivar. Our results show that lentil was more dependent on mycorrhizae than wheat and responded to an AMF inoculant even in soil containing high levels of indigenous AMF. It might, therefore, be possible to develop mixed inoculants containing rhizobia and AMF for field production of legumes.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s005720050156

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7

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Comparison of pyrites varying in water-soluble sulfur with gypsum for the reclamation of alkali soils under a rice-wheat rotation (1997)

Sharma, P. ; Swarup, A.

Springer

Biology and fertility of soils 24 (1997), S. 96-101

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ISSN: 1432-0789

Keywords: Pyrites ; Pyrite oxidation ; Gypsum Alkali soil ; Reclamation ; Soluble sulfur Welland rice ; Wheat ; Thiobacillus thioxidans ; Thiobacillus ferrooxidans

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract We evaluated the effect of agricultural-grade (AG) pyrites (total sulfur 22%) varying in water-soluble sulfur (1–8%) and gypsum on the soil properties and yields of rice and wheat in alkali soils during the years 1993–1995 at the Gudha and Saraswati experimental farms at the Central Soil Salinity Research Institute, Karnal, India. Gypsum and pyrites were applied on the basis of gypsum requirement (GR) of the soils. Results showed that the efficiency of AG pyrites in decreasing soil pH and exchangeable sodium percentage (ESP) and increasing crop yields was dependent on their water-soluble sulfur content at the time of application to the field. Pyrites with 5.5% and 8% soluble sulfur were as effective as gypsum. The freshly mined pyrite (water-soluble S 1%) was found to be inefficient in reclaiming alkali soils. We also explored the possibility of increasing the water-soluble sulfur content of pyrite by optimizing its storage conditions. When pyrite (1% water-soluble S) was stored under moist conditions by sprinkling water over the bags under a rain shelter, there was an enrichment of indigenous iron- and sulfur-oxidizing bacteria of pyrite, and the water-soluble sulfur increased to 5% within a period of 6 months. However no such increase occurred when pyrite was stored dry. We conclude that the soluble sulfur content of pyrite increased during its storage under moist conditions and should be between 6% and 8% at the time of its application to the field.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01420227

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8

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Comparison of pyrites varying in water-soluble sulfur with gypsum for the reclamation of alkali soils under a rice-wheat rotation (1996)

Sharma, P. ; Swarup, A.

Springer

Biology and fertility of soils 24 (1996), S. 96-101

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ISSN: 1432-0789

Keywords: Key words Pyrites ; Pyrite oxidation ; Gypsum ; Alkali soil ; Reclamation ; Soluble sulfur ; Wetland rice ; Wheat ; Thiobacillus thioxidans ; Thiobacillus ferrooxidans

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract We evaluated the effect of agricultural-grade (AG) pyrites (total sulfur 22%) varying in water-soluble sulfur (1–8%) and gypsum on the soil properties and yields of rice and wheat in alkali soils during the years 1993–1995 at the Gudha and Saraswati experimental farms at the Central Soil Salinity Research Institute, Karnal, India. Gypsum and pyrites were applied on the basis of gypsum requirement (GR) of the soils. Results showed that the efficiency of AG pyrites in decreasing soil pH and exchangeable sodium percentage (ESP) and increasing crop yields was dependent on their water-soluble sulfur content at the time of application to the field. Pyrites with 5.5% and 8% soluble sulfur were as effective as gypsum. The freshly mined pyrite (water-soluble S 1%) was found to be inefficient in reclaiming alkali soils. We also explored the possibility of increasing the water-soluble sulfur content of pyrite by optimizing its storage conditions. When pyrite (1% water-soluble S) was stored under moist conditions by sprinkling water over the bags under a rain shelter, there was an enrichment of indigenous iron- and sulfur-oxidizing bacteria of pyrite, and the water-soluble sulfur increased to 5% within a period of 6 months. However no such increase occurred when pyrite was stored dry. We conclude that the soluble sulfur content of pyrite increased during its storage under moist conditions and should be between 6% and 8% at the time of its application to the field.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01420227

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9

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Interaction of 15N-labelled ammonium nitrate, urea and ammonium sulphate with soil N during growth of wheat (Triticum aestivum L.) under field conditions (1995)

Hamid, A. ; Ahmad, M.

Springer

Biology and fertility of soils 20 (1995), S. 185-189

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ISSN: 1432-0789

Keywords: 15N-labelled fertilizer ; Added N interaction Fertilizer N uptake ; Soil N uptake ; Wheat ; Triticum aestivum

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract The effects of 15N-labelled ammonium nitrate, urea and ammonium sulphate on yield and uptake of labelled and unlabelled N by wheat (Triticum aestivum L. cv. Mexi-Pak-65) were studied in a field experiment. The dry matter and N yields were significantly increased with fertilizer N application compared to those from unfertilized soil. The wheat crop used 64.0–74.8%, 61.5–64.7% and 61.7–63.4% of the N from ammonium nitrate, urea and ammonium sulphate, respectively. The fertilizer N uptake showed that ammonium nitrate was a more available source of N for wheat than urea and ammonium sulphate. The effective use of fertilizer N (ratio of fertilizer N in grain to fertilizer N in whole plant) was statistically similar for the three N fertilizers. The application of fertilizer N increased the uptake of unlabelled soil N by wheat, a result attributed to a positive added N interaction, which varied with the method of application of fertilizer N. Ammonium nitrate, urea and ammonium sulphate gave 59.3%, 42.8% and 26.3% more added N interaction, respectively, when applied by the broadcast/worked-in method than with band placement. A highly significant correlation between soil N and grain yield, dry matter and added N interaction showed that soil N was more important than fertilizer N in wheat production. A values were not significantly correlated with added N interaction (r=0.719). The observed added N interaction may have been the result of pool substitution, whereby added labelled fertilizer N stood proxy for unlabelled soil N.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00336556

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10

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Solubilization of hydroxyapatite by Enterobacter agglomerans and cloned Escherichia coli in culture medium (1997)

Kim, K. Y. ; McDonald, G. A. ; Jordan, D.

Springer

Biology and fertility of soils 24 (1997), S. 347-352

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ISSN: 1432-0789

Keywords: Key words Phosphate-solubilizing bacteria ; Hydroxyapatite ; Enterobacter agglomerans ; Organic acids ; Phosphate-solubilizing genes ; Rhizosphere ; Wheat

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract Phosphate-solubilizing bacteria (PSB) possessing the ability to solubilize insoluble inorganic phosphate were isolated from the rhizosphere soil of wheat. A laboratory study was conducted to investigate the solubilization of phosphate by a known PSB, Enterobacter agglomerans, and by a genetically manipulated bacterium, Escherichia coli. A second laboratory study investigated the release of P from E. agglomerans compared with known acids. For the first laboratory study, a cosmid (pHC79) library of phosphate-solubilizing gene(s) from E. agglomerans chromosome DNA was constructed in E. coli JM109. The clone JM109 (pKKY) showing phosphate solubilization properties was screened on standard medium containing hydroxyapatite (HY). The P concentration significantly increased at 5 and 10 days for JM109 (pKKY) compared with JM109 (pHC79), the control. Although the P concentration increased, there was no significant change in their pHs. Furthermore, an increase in colony-forming units (CFUs) was seen at 5 and 10 days for JM109 (pKKY) but not for JM109 (pHC79). Artificial acidification of the culture medium with HCl, citric acid, oxalic acid, and lactic acid was achieved by shaking for 48h. Acidification with these selected acids solubilized more HY than E. agglomerans growing for 42h at similar pHs. However, a high P concentration was measured in culture medium with E. agglomerans growing for 84h despite similar pHs. Our results suggest that acid production may play an important role in HY solubilization, but is not the sole reason for the increase in P concentration in culture medium.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s003740050256

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