Bibliography: leaves 177-181. / v, 181 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Chemistry, 1999

Neural stem cells (NSCs) are defined as multipotent stem cells. They are able to self-renew and differentiate into mature cells, such as neurons, oligodendrocytes and astrocytes. Neurotoxicity of lead (Pb2+) has been extensively investigated by many previous studies. These studies proved that lead is a potent toxin that affects nervous system, especially children’s brain. However, most of these studies focused on the negative effects of lead on the differentiated or mature cell types in the brains instead of NSCs. The aim of this study was to reveal the effects of Pb2+ on viability, proliferation and differentiation of NSCs derived from the hippocampus of newborn rats aged 7 days and adult rats aged 90 days in vitro. NSCs harvested from the rat hippocampus were cultured in proliferation medium. After 6-8 days, free-floating neurospheres formed. The neurospheres were dissociated and plated onto poly-L-lysine coated 96-well plate and coverslips. Some dissociated cells were characterized by being stained with anti-nestin to show the presence of NSCs. This project was divided into three parts. In the first part, the Passage 2 (P2) cells plated onto 96-well plate were cultured in the proliferation medium with different concentrations of lead acetate (0-200μM) for 48 hours, followed by 3- (4,5-cimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay to detect the effects of Pb2+ on the cell viability. In the second part, P2-NSCs plated onto coverslips in wells were cultured in the proliferation medium with different concentrations of lead acetate (0-200μM). Then, 10 μM bromodeoxyuridine (BrdU) was added into the culture medium for additional 24 hours, followed by immunocytochemistry staining with anti-BrdU. In the last part, the dissociated P2-NSCs plated onto coverslips were allowed to grow in the differentiation medium of neurons, astrocytes or oligodendrocytes with different concentrations of lead acetate (0-200μM). After 6 days, immunocytochemistry staining with anti-microtubule-associated protein 2 (anti-MAP2), anti-glial fibrillary acidic protein (anti-GFAP) or anti-RIP was used to detect the differentiation commitment of affected NSCs. Low level of Pb2+ (1-10μM) had no effect on the viability of adult hippocampal neural stem cells (hNSCs). However, Pb2+ exposure at the concentration of 10μM could lead to significant cell death of newborn hNSCs. High level of Pb2+ (50-200μM) caused significant cell death of both newborn and adult hNSCs. Newborn hNSCs were sensitive to Pb2+ toxicity in proliferation assay. Even a low concentration (1μM) of lead could lead to significant inhibition of cell proliferation. High level of Pb2+ (50-200μM) suppressed proliferation of both newborn and adult hNSCs significantly. Moderate to high levels of Pb2+ exposure (50-200μM) significant decreased the percentage of mature neurons cultured from both newborn and adult hNSCs. Furthermore, 10μM or more Pb2+could significantly inhibited the oligodendrocyte differentiation of both newborn and adult hNSCs. However, Pb2+ could also stimulate the astrocyte differentiation of hNSCs. Lead concentrations higher than 10μM and 50μM could respectively lead to a significant increase in the percentage of mature astrocytes differentiated from newborn and adult hNSCs. The data showed that Pb2+ inhibited not only the viability and proliferation of rat hNSCs but also the neuronal and oligodendrocyte differentiation in vitro; moreover activated astrocyte differentiation of the hNSCs of both newborn and adult rats were observed with high concentration of Pb2+ in vitro. Also, it was revealed that the hNSCs of newborn rats were more sensitive than those from adult rats to Pb2+ cytoxicity. / published_or_final_version / Anatomy / Master / Master of Medical Sciences

Thesis (Ph. D.)--University of Missouri--Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves : 242-262). Also available on the Internet.

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Errata pasted onto front end-paper. / Bibliography: leaves 173-188. / xii, 188 leaves : ill. (chiefly col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Describes a comprehensive study of a select but informative set of crown ether ligands that may potentially be used in the development of a fluorescent lead (II) specific probe. / Thesis (Ph.D.)--University of Adelaide, Dept. of Chemistry, 1999

Problems related to estimating soil ingestion by wildlife species from analysis of feces were examined. Soil ingestion was investigated as a means by which wildlife may be exposed to environmental contaminants, particularly Pb. Titanium (Ti) and acid-insoluble residue (AIR) tracer methods for estimating soil ingestion were compared. The two methods were not significantly (P > 0.05) different when diet consisted of 10% (dry weight, d.w.) soil. When diet contained 5% soil, soil ingestion was more accurately estimated using the Ti method. Digestibility of soil can be ignored in the equation for quantifying soil ingestion from analysis of feces. Soil ingestion, as percentage dry matter intake (% DMI), by five wildlife species was estimated from analysis of feces or intestinal contents using the Ti tracer method. Soil ingestion by mourning doves (Zenaida macroura) was estimated using AIR analysis of crop contents. Mean (± S.E.) soil ingestion by Canada geese (Branta canadensis) and mallards (Anas platyrhynchos) were 4.92 (± 0.60) and 11.73 (± 1.54), respectively. Diets of short-tailed shrews (Blarina brevicauda) consisted of 5.20 (± 1.87)% soil, white-footed mice (Peromyscus leucopus) 16.21 (± 4.85)%, meadow voles (Microtus pennsylvanicus) 2.01 (± 0.34)%, and mourning doves 0.83 (± 0.41)% soil. Mallards collected from Killarney Lake, northern Idaho were analyzed for free erythrocyte protoporphyrin, fecal, liver, and kidney Pb concentrations, and soil/sediment ingestion. Sediment from the area contained 4485 ppm Pb (d.w.). Protoporphyrin was a poor indicator of Pb contamination at this level of exposure and/or under these conditions. Soil/sediment ingestion by mallards averaged 7.5% DMI. Tissue Pb concentrations indicated mallards were suffering from chronic exposure to low concentrations of Pb. Sediment collected from Killarney Lake (4485 ppm Pb) was fed to northern bobwhites (Colinus virginianus) at 8% DMI for 21 dad. Lead concentrations in blood, liver, and kidneys were determined and compared to control values. Treated and control birds showed no significant decline (P > 0.05) in feed intake and body mass did not change by greater than ± 1% over time. Lead in treated birds averaged 7 ppm (d.w.) in liver, 30 ppm (d.w.) in kidneys, and 126 ppb (wet weight, w.w.) in blood. Liver and kidney Pb concentrations of controls were < 0.1 ppm (d.w.) and averaged 630 ppm (w.w.) in blood. / Master of Science

No description available.

Thesis (MTech (Environmental Health)--Cape Peninsula University of Technology, 2007 / The widespread use of lead (Pb) and especially Pb from vehicular emissions arising from lead additives in petrol has resulted in high levels of this metal found in various soil samples taken along the road verges of Cape Town CBD. The accumulation of lead was investigated in roadside surface soil by collecting soil samples at various sites along the three major highways (N7, N2, N1), approximately three metres from the road verges and at a depth of approximately 5 cm for a period of 12 months. After digestion with 55"70 nitric acid the Pb concentrations were determined by using an Inductively Coupled Plasma Atomic Emission Spectrophotometer (ICP-AES). Results have shown the Pb concentrations in the soil at busy intersections to be higher than at other areas along the roadsides. Lead concentrations found in the roadside soils of the N1 ranged between 200 and 2000 mg/kg and these were of the highest concentrations found compared to the other two highways and were even higher than found in other studies. The roadside soils on the N1 highway, with the most traffic, according to car count data obtained, seemed more contaminated than the other two highways. It was also investigated whether earthworms (Eisenia fetida) accumulated Pb after being exposed to the contaminated soil from the sampling sites. The earthworms in the highly contaminated soil accumulated on average much higher concentrations of Pb than the earthworms in the lower Pb contaminated soil. A potential biomarker (cell membrane integrity) was applied to determine whether the earthworms experienced toxic stress as a result of the exposure to lead contaminated soil. Behavioural and morphological changes in the earthworms were also observed. The Trypan blue exclusion assay was used to measure the effect of lead exposure on the membrane stability of the coelomocytes in the coelomic fluid of earthworms. In the highest exposure groups per highway, a significant decrease in percentage viable cells were seen (N7, 36 ± 0.07%; N2 48 ± 0.09%; N1, 34 ± 0.08%). The fact that clear statistically significant responses were seen after the five week exposure period in the highest, as well as lowest exposure groups indicate that these responses could serve as an early warning system of lead exposure. The percentage cell viability (biomarker) used in this study have been useful in identifying toxic stress in earthworms caused by lead in roadside soils. The additional information obtained by using biomarkers could not be obtained by chemical analysis of soil and earthworms alone.

Wild birds can be exposed to high concentrations of lead caused by spent lead shot and industrial waste. The immunosuppressive effects of lead have been demonstrated in laboratory mammals, but little research has been conducted in birds. Because immunocompetence is important for survival, the effects of acute lead exposure on immune function in 2 quail species, Japanese quail (Cotumix coturllix) and northern bobwhites (Colinus virginianus), were investigated. In preliminary experiments, intubation with lead shot produced inconsistent doses within treatment groups. Both quail species exhibited poor antibody responses after immunization with sheep erythrocytes. In a third experiment, male Japanese quail were dosed with 100 or 400 ppm lead in drinking water for 7 days. Quail were fed either laying mash or com. Some quail were treated with corticosterone as a positive control Lead enhanced the loss of body mass caused by com. Lead-induced mortality was observed only in quail fed com. There was marginal evidence that lead increased the heterophil to lymphocyte ratio in quail fed com. Com decreased the cell-mediated immune response to an intradermal injection of phytohemagglutinin. Corticosterone suppressed cell-mediated immunity more than lead. The primary total antibody response to chukar (Alectoris graeca chukar) erythrocytes was significantly suppressed in lead-dosed quail fed com. Lead also reduced the secondary total antibody and IgG responses in the low lead/com group. The most pronounced effect of lead on immune function was a suppression of antibody responses in groups that exhibited clinical lead poisoning. / Master of Science

The mussel bed and its multitude of inhabitants form a life community typical of our intertidal, rocky, open-coast areas. These animals are essentially immobile, are conveniently available at low tide, and have been well defined in their consumer order. Certain main members from this community were chosen with the intention that they would represent an index of heavy metal pollution for a given area under different seasonal and other variable conditions. Samples for monitoring were collected from two different sites. The first site was immediately outside the entrance to San Francisco Bay and located between Seal Rocks and Phelan Beach State Parks. This location was chosen to represent a water mass of supposed maximum pollution. The Golden Gate can be assumed to be the funnel through which flows all waters from the San Joaquin and Sacramento River drainages and from the San Francisco Bay area itself. The second site, immediately north of the Dillon Beach township, located at the juncture of Bodega and Tomales Bays, was chosen since it might represent a water mass of minimum pollution. This area is not immediately near any large urban influence, industrial activity or subject to heavy auto traffic. Therefore, at the outset it was hoped that the “immobile” consumer order within the mussel bed community would reflect the relative pollution of two supposedly different water masses.