Determination of natural and depleted uranium in urine at the ppt level: an interlaboratory analytical exercise.

An analytical exercise was initiated in order to determine those procedures with the capability to measure total uranium and uranium (238U/235U) isotopic ratios in urine samples containing >0.02 microg U kg-1 urine. A host laboratory prepared six identical sets of twelve synthetic urine samples containing total uranium in the range of 25 to 770 ng U kg-1 urine and with 238U/235U isotopic ratios ranging from 138 (100% NU) to 215 (51% DU). Sets of samples were shipped to five testing laboratories (four based in Canada and one based in Europe). Each laboratory utilized one of the following analytical techniques: sector field inductively coupled plasma mass spectrometry (ICP-SF-MS), quadrupole inductively coupled plasma mass spectrometry (ICP-Q-MS), thermal ionization mass spectrometry (TIMS), and instrumental/delayed neutron activation analysis (I/DNAA), in their analyses.

Analysis of a complex vertical copulatory-courtship display in the yellow fever vector Sabethes chloropterus.

Sabethes chloropterus (Von Humboldt) (Diptera: Culicidae), an arboreal mosquito vector of the yellow fever virus, perches on vertical surfaces, where airborne males patrol for potential mates and mating occurs. Laboratory analysis of 26 virgin mating pairs partly confirms and greatly extends an earlier description suggesting that males perform a courtship ritual. A male approaches a female by hovering behind her, moving toward her from one side, reaching toward her and occasionally touching her with his closest midleg, and eventually seizing her wing with that midleg and inverting beneath her, forelegs against the substrate. Immediately after male alignment with the female, the pair enters a superficial genital-coupling phase, in which the male's extended gonostyli are linked to the female, and he proceeds sequentially through four stages of midleg oscillations (MLOs): Alternate I, Synchronous I, Double-flex, and Synchronous II. Following one or more genital thrusts, the pair shifts to a full-copulation phase, which lasts only up to 6 s, during which the genitalia are clasped and insemination occurs. The male raises his midlegs and hindlegs in succession, then performs Alternate II MLO until the female kicks him and he is released. Nineteen (73%) of the 26 pairs successfully completed the entire sequence, including genital shift and full copulation, taking an average of 3.7 min. Features of the display that might determine success were not evident. Reversions in the chain of events occurred, but linear progression of stages and phases was characteristic of nearly all matings. The male's approach, however, lacked stereotypic form and probably is not part of the courtship.

An examination of uranium levels in Canadian forces personnel who served in the Gulf War and Kosovo.

A uranium bioassay program was conducted involving 103 active and retired Canadian Forces personnel. The total uranium concentrations in each of two 24-h urine collections were analyzed separately at independent commercial laboratories by inductively coupled plasma mass spectrometry (ICP-MS) and by instrumental neutron activation analysis (INAA). The mean and median concentrations were determined to be 4.5 ng L(-1) and 2.8 ng L(-1), respectively, from ICP-MS and 17 ng L(-1) and 15 ng L(-1), respectively, from INAA. The total uranium concentrations were sufficiently low so that isotopic (238U:235U ratio) assays could not be performed directly from urine samples. Isotopic assays were performed on hair samples from 19 of the veterans participating in the testing. The isotopic hair assays were scattered around the natural 238U:235U ratio of 137.8, ranging from 122 +/- 21 to 145 +/- 16 (1sigma). Due to concern expressed in the media over possible depleted uranium exposure and long-term retention in bone, a single bone sample (vertebrate bone marrow) from a deceased member of the Canadian Forces was also analyzed for total uranium content and isotopic ratio by ICP-MS. The sample was shown to have 16.0 +/- 0.3 microg kg(-1) uranium by dry weight and a 238U:238U isotopic ratio of 138 +/- 4, consistent with natural uranium.

Mineralogical and chemical interactions of soils eaten by chimpanzees of the Mahale Mountains and Gombe Stream National Parks, Tanzania.

Termite mound soils eaten by chimpanzees of the Mahale Mountains and Gombe National Parks, Tanzania, have mineralogical and geochemical compositions similar to many soils eaten by higher primates, but release very low levels of either toxic or nutritional inorganic elements to solution at acid pH. Comparison with control (uneaten) soils from the same areas showed lower levels of carbon and nitrogen in the eaten soils, a relationship confirmed by surface analysis. Surface analysis also revealed lower levels of iron on particle surfaces versus interiors, and higher levels of iron on ingested versus control soil particle surfaces. The soils can adsorb dietary toxins, present in the plant diet or those produced by microorganisms. Taking the toxic alkaloids quinine, atropine, sparteine, and lupanine as examples, it is evident that soils from Mahale have a very good adsorptive capacity. A new adaptive advantage of geophagy is proposed, based on the prevention of iron uptake. The behavior of the soils in vitro is consistent with the theory that geophagy has a therapeutic value for these chimpanzees.

Exogenous juvenile hormone and methoprene, but not male accessory gland substances or ovariectomy, affect the blood/nectar choice of female Culex nigripalpus mosquitoes.

When newly emerged females of the mosquito Culex nigripalpus Theobald (Diptera: Culicidae) take a sugar meal, they develop both a propensity to seek a host and resting-stage ovarian follicles. As follicle growth is indicative of Juvenile Hormone (JH) activity, we searched for possible roles of JH in the behavioural shift from nectar to blood-host odour preference by Cx. nigripalpus after emergence, using an olfactometer-choice assay. Topically applied or injected methoprene (a JH analogue) resulted in a behavioural shift and follicular growth in unfed females that increased with increasing dosages. Topical methoprene 500 ng and 4 microg resulted in a switch to bird-odour preference. JH III injection resulted in a lesser shift from honey responses to bird responses. Methoprene application caused no detectable changes in glycogen, total sugars or total lipid when assayed 24h after treatment. Additionally, as male accessory glands (MAG) have been shown to synthesize JH, we implanted intact paired MAGs from either conspecific or Aedes aegypti (L.) donors, or injected 1/3 gland pair equivalents of conspecific MAG homogenate into unfed newly emerged females. All MAG treatments failed to induce behavioural or ovarian modifications. Ovariectomy had no effect on the sugar-induced shift from nectar to host preference in the olfactometer. Thus JH, but not MAG, mimicked the effects of a sugar meal by causing both follicular growth and the shift to preference for a host.

Larval and adult nutrition effects on blood/nectar choice of Culex nigripalpus mosquitoes.

The impact of nutritional variables on the development of host-seeking and biting behaviours after emergence by female Culex nigripalpus mosquitoes were studied using air-flow olfactometer and close-range biting assays, respectively. Unfed females failed to develop resting stage ovarian follicles. When offered a bird host in the absence of competing stimuli, sugar-fed mosquitoes were significantly more responsive in both host-seeking and biting than unfed controls. In a choice olfactometer assay using nectar odours (honey scented with artificial apple-blossom oil) versus host odours (a bird), unfed females preferred honey over bird odours except when honey odour was weak. After sucrose feeding, females switched from honey to bird preference. This change in behaviour was accompanied by significant accumulation of lipid and by follicular growth to the resting stage. Elevation of host responsiveness after sugar feeding was reversible; starvation ultimately resulted in females preferring honey over bird odours. When the larval diet was restricted by crowding, the wing-length and total lipid of resultant adult females were reduced. Although differences were subtle, unfed bird-responding females tended to have longer wings and more lipid than their honey-responding counterparts.

Geochemical evidence of pollutants from coalfired generating stations in late Pleistocene palaeosols in the Dalijia Shan, northwestern China.

Surface palaeosols in two tills and a diamicton from an area in northwestern China were analysed for geochemical pollutants. Elevated levels of Br, As and Sb indicate that pollution from coal-burning and/or coal-fired electricity generating stations is delivered by aeolian transport into palaeosols dating from the last glaciation. Because the climate in the field area is sub-humid (precipitation <760 mm) the relative movement of soluble elements in palaeosols dating from early and late stades of the last glaciation is not expected to be high. The glacial and aeolian parent materials of the palaeosols indicate differences that are probably related to their source areas and to the incorporation of geochemical pollutants.

Marginal bleaching of thalli of Rhizocarpon as evidence for acid rain in the Norra Storfjället, Sweden.

Recent lichen surveys in the foreland of The Syterbäcken glacier reveal that the crustose lichens, principally species of Rhizocarpon section Rhizocarpon, exhibit marginal bleaching, readily distinguishable from normal pigmented forms. The largest elliptical thallus of Rhizocarpon measured 290 mm maximum diameter on a bedrock outcrop beyond the margin of Little Ice Age moraines in the upper Syterbäcken Valley. Many small and large thalli of Rhizocarpon suffered damage to the periphery of individual thalli. We examine here some of the possible hypotheses explaining these occurrences. Among others, these are bedrock lithology, ice crystal blasting, long-term snowbank cover, ultraviolet exposure and acid rain. While at this time none of the possibilities can be ruled out entirely, acid rain would appear to be at least one of the factors involved. Acid rain, which is known to produce a soil pH as low as 3.3 in the field area, appears to provide a high input of H(+) ions that the lichen algal component cannot withstand. However, the lack of similar effects on associated foliose or fruticose forms raises the possibility that perhaps two or more factors specific to the environment of Rhizocarpon are operating.

Energy-dispersive X-ray microanalysis of the bone mineral content in human trabecular bone: a comparison with ICPES and neutron activation analysis.

To evaluate the accuracy of bone mineral composition determination by electron microprobe analysis (EDX) the measurements have been compared to instrumental neutron activation analysis (INAA) and chemical analysis (ICPES). Bone specimens from five femoral heads were used. The trabecular content of calcium (Ca) and phosphorus (P) was analyzed by the three different methods. The EDX method allows for a microstructural analysis of intact, methylmetacrylate-embedded, undecalcified bone and the measuring points can thus be distinctly identified centrally in each trabecula. The analysis yielded 25.8 +/- 0.7 wt % Ca and 10.5 +/- 0.1 wt % P, compared with 22.2 +/- 0.5 and 23.0 +/- 1.0 wt % Ca, and 9.83 +/- 0.21 and 10.02 +/- 0.44 wt % P for INAA and ICPES, respectively. The EDX analysis was calibrated by consecutive measurements of a hard, pressed tablet of hydroxyapatit of known content. The mean Ca content deviated with -0.38 wt % from the given content and P with -0.89 wt %. We could not verify any particular interference from the embedding procedure, however, it is possible that the relatively lower P content still may reflect this. The magnesium (Mg) concentration was 0.31 +/- 0.02 wt % by EDX and 0.26 +/- 0.02 wt % by INAA. The EDX analytical method provides a useful tool for simultaneous elemental quantification in bone. It has the advantage of permitting the use of regular bone biopsy material and thus allowing for a unique microstructural evaluation of the degree of mineralization.(ABSTRACT TRUNCATED AT 250 WORDS)

Nectar-related olfactory and visual attractants for mosquitoes.

Mosquitoes commonly feed on plant nectar and other sugar sources, which they locate chiefly by visual and chemical cues. A summary of current evidence indicates that nectar sources are not as attractive as blood sources at specific times in a mosquito's life but that sugar feeding is usually necessary and more frequent than bloodfeeding. Plant attractants used in traps would have the advantage of being effective for both sexes, starting soon after emergence, and for blood-digesting, gravid, and gonoinactive females. Field studies suggest that mosquitoes are most attracted to light-colored flowers, but the independence of appearance from fragrance has not been firmly established. Volatile components of flowers and honey have been proven to be attractive, but in a preliminary field trial honey extract was less attractive than some blood-host kairomones. Terpenoids and aromatics provide many of the distinctive and dominant volatiles of flowers; they elicit both chemosensory and behavioral responses in mosquitoes.

De novo biosynthesis of juvenile hormone III and I by the accessory glands of the male mosquito.

The role of the male accessory glands (MAG) in reproduction was investigated in the mosquito Aedes aegypti. MAG incubated with [14C]acetate synthesized radioactively labeled JH III, JH III bisepoxide and methyl farnesoate. MAG incubated with L-[methyl-3H]methionine synthesized [3H]JH III and a molecule that chromatographed on HPLC with JH I. Analysis of MAG and whole males extract by glass capillary combined gas-chromatography-selected ion monitoring mass spectrometry identified JH III and I as the main analogs that were synthesized by male mosquitoes. MAG of Culex nigripalpus, Anopheles rangeli and Anopheles trinkae also synthesized JH III from L-[methyl-3H]methionine, which indicates that the male mosquito has a complete JH III biosynthetic pathway. Unfed and unmated Culex quinquefasciatus do not develop their ovaries to the resting stage. Females injected with one MAG extract equivalent or implanted with A. aegypti MAG developed their ovaries to the resting previtellogenic stage, whereas females that were injected with saline did not. These results indicate that MAG synthesize and secrete JH III. The corpora allata (CA) of the male Aedes aegypti also synthesize JH III from L-[methyl-3H]methionine. This observation may suggest that JH synthesized by the male's CA is used for internal regulation, whereas JH synthesized by the MAG is transferred with the sperm into the female.

The effects of diet, age, and sex on the mineral content of primate bones.

The effect of diet, age, and sex on the mineral content of primate bones was determined for free-ranging rhesus monkeys (Macaca mulatta) from the Caribbean Primate Research Center. Monkeys in this study were of known age and sex and had been provided with either a low protein (15%) or a high protein (25%) diet for most of their lives. Instrumental neutron activation analysis was used to assess bone mineral content. Results showed that diet had no significant effect on the bulk mineral composition of Ca, Mg, Br, and Cl in the bones. Of the minerals analyzed, only Na and Mn showed significant diet-related effects. The bone Ca content was found to be lower in females than in males when controlled for age. Finally, Ca content was found to be higher in young adults, lower at middle age, and higher in old age in both male and female monkeys. In conclusion, this study has shown that increasing protein content in the diet does not change the bulk mineral content of primate bones. The nondietary effect that Ca content of monkey bones is lower during middle age has not been previously reported.

Effects of preblood-meal sugar on sugar seeking and upwind flight by gravid and parous Aedes aegypti (Diptera: Culicidae).

Sugar seeking and upwind flight of gravid and parous female Aedes aegypti (L.) was measured by their attraction to honey in a dual-port airflow olfactometer at selected time intervals after a blood meal. Comparisons were made between pre-blood-meal sugar-fed and unfed females. Sugar-fed females had greater total energy reserves, mostly because of elevated lipid levels. Gravid mosquitoes in both groups showed a strong tendency to fly upwind. This appears to be a pre-ovipositional response. Gravid female orientation to honey was greater in unfed females than in sugar-fed females. After oviposition, parous females became more strongly attracted to honey, if their honey response was not already high.

Simultaneous field comparison of evening temporal distributions of nectar and blood feeding by Aedes vexans and Ae. trivittatus (Diptera: Culicidae) in Ohio.

Nectar- and blood-feeding time distributions of Aedes vexans (Meigen) and Aedes trivittatus (Coquillett) were determined from collections of mosquitoes attempting to feed on flowers and human bait during six nights in an Ohio field. Distributions of nectar and blood feeding were different in Ae. vexans on three of five nights when analyses were possible, and they were different in pooled Ae. trivittatus data. Higher proportions of blood feeders appeared in earlier time intervals, but both nectar and blood feeding had broadly overlapping peaks and distributions. These results suggest that the nectar- and blood-feeding rhythms are probably in phase in Ae. vexans females, and that possibly the earlier onset of blood feeding reflects a strategy taking advantage of blood when it is available. Male Ae. vexans had later peak nectar-feeding times than females. Nectar feeding in males may be delayed by mating activity early in the activity period.

Tests of Sabethes cyaneus leg paddle function in mating and flight.

Both sexes of the mosquito Sabethes cyaneus have conspicuous midleg paddles of unknown function. These paddles are displayed prominently by males during courtship. However, we found that paddle removal reduced successful mating of females, not males. Males without paddles approached and courted females normally, but females without paddles were rarely approached by males. Paddle removal appeared not to alter flight, and paddleless females oviposited in the manner characteristic of Sabethes, suggesting that the paddles do not aid in hovering or rapid reverse flight. We conclude that paddles of females are used in attracting males but that their function in males remains undetermined.

Pigmentation and temporal effects on trace elements in hair.

Variations in trace element concentration in the head and facial hair of five individuals with ever-increasing amounts of white hair were examined. Hair was collected from the scalp, cheeks, and chin from one donor on a regular basis since 1984. Samples were separated into white and pigmented fractions, and analyzed at SLOWPOKE-Toronto by INAA for the short-lived, isotope-producing elements Br, Ca, Cl, Cu, I, Mg, Mn, Na, S, and Zn. Temporal concentration variations of these elements over time, and variations of the elemental concentrations in pigmented and white hair were established.

Bone mineral and osteoporosis in aging rhesus monkeys.

55 femora of free ranging rhesus monkeys from the Caribbean Primate Research Center ranging in age from 2-25 years were analyzed using histology, density fractionation and chemical analysis and correlated with morphometric data. The vertebral density was determined by photon absorptiometry. 119 caudal vertebrae from the skeletal collection were analyzed chemically. Cortical mineral density and porosity increased with age, and vertebral density and cortical area increased with weight. There was significant sexual dimorphism in many histological variables reflecting size differences and cortical porosity was greater in males. The chemical analysis showed no influence of the diet on bone mineral but that Ca increase with age in females but not in males. Finally a subgroup of aged, animals had hypermineralized, and more porous bone. This subpopulation may prove to be a valuable model for senile osteoporosis.

Neutron activation analysis of bulk and selected trace elements in bones using a low flux SLOWPOKE reactor.

The mineral phase of bone is a reservoir for some biologically important ions and is the place where some toxic elements are also stored. For these reasons it is important to measure accurately and nondestructively the chemical content of bone, with respect to its main elements (Ca, P, Mg, Na) and its trace elements. We have analyzed different types of human bone by instrumental neutron activation analysis (INAA), using a SLOWPOKE reactor. We have compared our results with inductively coupled plasma emission spectroscopy (ICPES), and we have determined the limits of detection and sensitivity for the various elements, especially some biologically or toxicologically significant trace elements. Finally, we have given two examples of the use of INAA in following the penetration of an element (F) with time into bone and in characterizing nondestructively the mineral content of bone biopsies of a rare pathological condition (osteopetrosis).

Tissue selenium accretion in premature and full-term human infants and children.

Development of supplementation guidelines for formulated diets and total parenteral nutrition requires knowledge of Se tissue accretion. To this end, the total organ Se content was calculated from the Se concentrations that were measured by neutron activation analysis in postmortem samples of liver (n=56), kidney (n=11), adrenal cortex (n=9), and pancreas (n=6) from infants and children from birth to 10 yr including 17 born prematurely. Hepatic Se concentrations were similar in full-term and premature newborns, decreased from birth to 1 yr, and then increased thereafter. The total hepatic Se content was significantly greater in full-term than in preterm newborns and increased with age and liver size after 1 yr. No significant differences were found between the concentrations of Se in kidney, pancreas, and adrenal tissues. Falling hepatic Se concentrations in the full-term infant concurrent with stable total organ Se content may indicate inadequate dietary intake or may reflect a normal redistribution of the nutrient. Premature infants are born with smaller stores than full-term infants and are at greater risk of developing a deficiency.

The total and free concentrations of Ca2+ and Mg2+ inside platelet secretory granules. Measurements employing a novel double null point technique.

The inorganic ion contents of platelet alpha-granules were determined by a combination of neutron activation analysis and flame photometry. Total concentrations were estimated using intragranular water spaces measured by isotope dilution. To measure the free concentrations of Ca2+ and Mg2+ we developed a novel double null point titration technique. The method requires independent determinations of transmembrane delta pH and the availability of two divalent cation-H+ exchange ionophores with different Ca2+/Mg2+ selectivity ratios. A23187 and the halogenated analog 4-bromo-A23187 were used for this purpose. Absolute delta pH was measured by methylamine distribution, while relative pH changes induced by the ionophores were monitored with 9-aminoacridine. The free concentrations of Ca2+ and Mg2+ were found to be 12 and 326 microM, respectively. These values are markedly lower than the calculated total concentrations of these cations, i.e. 32 mM for Ca2+ and 172 mM for Mg2+.