PubMed Health⌕ Search

Biomedical subjects

N I Ward

Publications and source records attributed to N I Ward.

At least 19 recordsLinked to original sources
PubMed1997

Trace elements in drinking and groundwater samples in southern Nigeria.

The levels of Al, Sn, Cs, Rb, Sr, Br, Cr, Mo, Co, Ba, Cu, Zn, Cd, Pb, Mn, Se, As, V and Ni were determined in drinking water supplies (public taps, domestic taps and treated water from public water sources) and groundwater supplies (boreholes and shallow wells) in some parts of Southern Nigeria. The water samples were analysed using inductively coupled plasma mass-spectrometry (ICP-MS). The mean levels (microgram/l) of all the elements ranged between 0.35 microgram/l for Cs and 87.3 micrograms/l for Zn in the drinking waters and between 0.54 microgram/l for Co and 420.3 micrograms/l for Ba in the groundwaters. A comparison of the elemental concentrations with WHO guidelines showed that with the exception of violations of Cd, Cr and Se limits in some of the drinking water samples, the levels of all the other elements investigated were below the WHO maximum allowable concentrations.

Environmental Monitoring↗
PubMed1994

Elemental status of grazing animals located adjacent to the London Orbital (M25) motorway.

The elemental (Br, Cd, Cr, Cu, Mn, Ni, Pb, Se, V, and Zn) content of blood and wool or hair from animals (sheep, horses and alpacas) exposed to motor vehicle emissions alongside the London Orbital (M25) motorway is reported. Elemental values were determined by inductively coupled plasma mass spectrometry (ICP-MS) quality control assessment using flameless atomic absorption spectroscopy (for Pb, correlation coefficients of whole blood r = +0.87, and hair r = +0.82), and replicate (n = 10) analysis of the international reference material IAEA A13 Animal Blood. For Pb very good agreement was obtained between ICP-MS values 0.16 +/- 0.002 microgram/g and non-certified values 0.18 microgram/g. Only Pb and Cd showed significantly elevated blood levels in sheep grazing alongside the M25 motorway when compared with control (background) animals. The range of Pb blood values was 0.15-0.51 microgram/ml (M25) and 0.04-0.18 microgram/ml (control), respectively. The elemental content of the outside (tip) end of wool samples for the two study groups were significantly elevated in Br, Cd, Cr, Cu, Ni, Pb, V, and Zn for M25-exposed animals compared with controls. Elevated Pb and Cd were also found in horses' and alpacas' blood or hair in animals exposed to transportational activities. The relationship between whole blood and outer wool or hair Pb showed a very highly significant correlation for sheep (r = +0.89), horses (r = +0.69), and alpacas (r = +0.74) grazing alongside the M25 motorway.

Air Pollutants↗
PubMed1994

Metal dispersion and transportational activities using food crops as biomonitors.

The multielement (Al, Ca, Cd, Ce, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Si, and Zn) levels of various common vegetables (bean, broccoli, cabbage, cauliflower, lettuce, marrow, onion, parsnip, spinach, sprouts, sweet corn, and tomato); fruits (grape and strawberry); herbs (garlic, lemon balm, marjoram, mint, rosemary and tarragon); local pasture species and surface soils collected from a commercial garden centre located within a distance of 30 m of the London Orbital Motorway (M25) is presented. Comparative values are given from a background area, namely a domestic garden located in the North Yorkshire Dales National Park area. Analysis was undertaken by inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma-source mass spectrometry (ICP-MS) with quality control assessment using four international biological reference materials; BCR:CRM 62 Olive Leaves, NIST 1575 Pine Needles, NIST 1573 Tomato Leaves, and NIST 1572 Citrus Leaves. Inter-analytical method comparison is given using two methods of ICP-MS; namely conventional pneumatic nebulisation of sample solution, and direct solids analysis by laser ablation; and neutron activation analysis methods (NAA). For the elements listed there is a good precision obtained by ICP-MS and NAA. In particular levels of < +/- 1-10% (rsd) are obtained. Comparison of data with certified values and other analytical methods are generally of very good agreement. Lead levels in background areas ranged from 0.0008 to 0.340 microgram/g (fresh weight) for plant material; with the lead magnitude greater for grasses > herbs > vegetables > cereals > fruits. Measured values are in good agreement with reported literature values. The lowest Pb values are for marrow, lettuce, tomato and sweet corn samples (approximately 0.001-0.021 microgram/g). 'Green' leaf material levels were approximately 0.02-0.10 microgram/g (i.e. sprouts and cabbage). Root vegetables contain higher levels, approximately 0.02-0.125 microgram/g (especially carrot), reflecting possible metal uptake from soil. The highest vegetable Pb values are for leek and onion (approximately 0.35 microgram/g). Background values are also provided for nineteen elements (Al, As, B, Ba, Br, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Rb, Se, Sr, V, and Zn). Exposure to motor vehicle activities at a site some 30 m from the M25 shows only significant increases in Pb for unwashed plant material and surface soils. Typically Pb levels of 40-80% can be removed by washing plant surfaces resulting in metal levels similar to background areas.(ABSTRACT TRUNCATED AT 400 WORDS)

Air Pollutants↗
PubMed1993

Hippocampal tin, aluminum and zinc in Alzheimer's disease.

The use of inductively coupled plasma source mass spectrometry (ICP-MS) for multi-element analysis has led to the observation, in two separate studies, of increased blood tin in Alzheimer's disease (AD). We have therefore applied the technique of ICP-MS to hippocampal tissues obtained post-mortem from patients with AD and from controls. There was no significant difference in tin concentrations in AD. There were increased concentrations of aluminum and silicon, and reduced concentrations of zinc and selenium. It is postulated that displacement of hippocampal zinc by heavy metals may be important in producing clinical memory disturbance. However, analysis of the CA1 region, rather than of the dentate gyrus, would have been preferable.

Aged↗
PubMed1992

Trace elements and the electroencephalogram during long-term lithium treatment.

Endogenous bromine has been found to be raised during lithium treatment, and it has been suggested that it may augment the therapeutic effect of lithium. Our findings in a study of 12 patients and 12 controls support this contention. Electroencephalographic effects of bromine, vanadium and aluminium were studied--higher bromine and vanadium levels were associated with irregular cortical activity. Electroencephalographic abnormalities were associated with more side-effects of lithium.

Aluminum↗
PubMed1991

Tin and fatty acids in dementia.

Serum elements and fatty acids of red cell and plasma phospholipids, cholesterol esters and high density lipoproteins, were studied in patients with Alzheimer's disease (SDAT) and with multi-infarct dementia (MID). Increased 20:4n6 in MID was the finding most consistent in the different tissues. The red cell phospholipids were more unsaturated in MID than in SDAT but in SDAT the plasma phospholipids were more saturated. Serum Al, Sn and V concentrations were higher in SDAT than in MID while serum Mn concentrations were higher in MID. Sn and V correlated negatively with the unsaturation index of the red cell phospholipids and Sn showed a striking pattern of correlations with the red cell phospholipid fatty acids in SDAT: it was significantly positively correlated with 16:0 and 18:1n-9 and negatively correlated with 20 and 22 carbon n-3 and n-6 essential fatty acids. Since we have shown elevated tin levels in patients with Alzheimer's disease, and since organic tin compounds given to animals produce a syndrome with similarities to Alzheimer's disease, there is a need for investigation of the role of tin in lipid metabolism in dementia.

Aged↗
PubMed1991

Red cell caesium, lithium and selenium in abstinent alcoholics.

Using inductively coupled plasma source mass spectrometry, we have studied the red cell element concentrations of alcoholic subjects with different periods of abstinence before testing. We found consistently elevated red cell caesium concentrations and also reduced red cell selenium concentrations. These may represent persistent abnormalities in oxidation/anti-oxidation mechanisms, and red cell caesium in particular may be a long-term marker of alcohol dependence. Erythrocyte lithium, cerium and boron concentrations were also reduced in the abstinent alcoholic groups.

Adult↗
PubMed1990

Lead contamination of the London Orbital (M25) Motorway (since its opening in 1986).

The Watford and South Mimms sections of the London Orbital (M25) Motorway opened in late 1986. The rate of lead contamination in vegetation, surface soil, dust and airborne fractions since those dates is presented. Lead values were determined by inductively coupled plasma-source mass spectrometry (ICP-MS) with inter-analytical method comparison using flameless atomic absorption spectroscopy (NFAAS). A consistently high level of correlation (r = +0.91) was obtained for analysis of digested reference materials and (r = +0.84) for digested environmental sample solutions using these two methods. Quality control assessment was made using seven international reference materials covering the range of matrices under investigation. Analytical precision values (n = 20 replicates) for ICP-MS measured Pb levels in soil and vegetative reference materials are 6.1 to 11.1% and 3.3 to 7.1%, respectively. Overall accuracy of the analytical procedures used in this study is very good with a high degree of agreement between measured ICP-MS values and those either certified or reported in the literature. A rapid rate of Pb deposition occurs within the first months following the opening of the motorway in relation to emissions from approximately 90,000 vehicles day-1 (Watford) and approximately 75,000 vehicles day-1 (South Mimms). At 12 months elevated Pb levels extend to distances of greater than 100 m from the motorway.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollution↗
PubMed1989

The role of trace elements in male infertility.

The elemental status of seminal plasma collected from four populations subdivided on the basis of sperm counts is presented. Elemental analysis was performed by inductively coupled plasma-source mass spectrometry (ICP-MS) for calcium, cadmium, cobalt, chromium, copper, iron, magnesium, manganese, molybdenum, nickel, lead, rubidium, selenium, vanadium, and zinc. The majority of elements reflected no statistically significant differences among the four groups. The role of trace elements in infertility may be more directly related to sperm and whole semen than seminal plasma levels.

Humans↗
PubMed1988

Vanadium and other trace elements in patients taking lithium.

The serum concentrations of 24 trace elements were measured by neutron activation analysis in 32 patients on long-term lithium treatment and 32 age- and sex-matched healthy controls. Whole blood and hair samples were also taken from a number of these subjects. Compared to controls, patients on lithium were found to have a lower serum vanadium, a lower serum cobalt, and an elevated serum aluminium level. These findings are discussed.

Adult↗
PubMed1987

Further studies of vanadium in depressive psychosis.

Three studies are reported. In study 1, vanadium concentration was estimated by neutron activation analysis in hair, whole blood, serum and urine from 13 patients suffering from depressive psychosis and then when on recovery. Vanadium concentration of hair, whole blood and serum decreased significantly with recovery, but there was no significant change in 24-h urinary excretion or in renal clearance of vanadium. In study 2, vanadium concentration was estimated by neutron activation analysis in serum and urine of 31 patients with depressive psychosis and of 27 normal controls. Mean renal clearance of vanadium was significantly lower and mean serum vanadium concentration significantly higher in depressed patients than in controls. Mean 24-h excretion of vanadium did not differ between the two groups. Vanadium excretion did not correlate with urine volume, with serum concentration or with age. In study 3, erythrocyte Na-K ATPase activity and serum vanadium concentrations were estimated in 58 patients. There was a strong negative correlation between the two, supporting the suggestion that changes in tissue vanadium concentration may explain the changes in sodium transport which occur in depressive psychosis.

Adult↗
PubMed1985

Blood levels of vanadium, caesium, and other elements in depressive patients.

Levels of vanadium and 29 other elements were measured in whole blood of 25 depressive patients, 13 recovered depressive, and 24 control subjects. Vanadium levels were normal in depressive patients, and did not change on recovery. Changes of doubtful significance were found in blood levels of copper, strontium and chromium on recovery from depressive illness. The depressive patients had reduced blood levels of caesium which increased towards normal on recovery. This finding is discussed in relation to pertinent neurochemical and behavioural effects of caesium.

Adult↗
PubMed1984

Fasting plasma magnesium concentrations and glucose disposal in diabetes.

Fasting plasma concentrations of magnesium were measured by neutron activation analysis in 30 non-diabetics and 87 diabetics (55 non-insulin-treated, 32 insulin treated). Plasma concentrations of magnesium were lowest in the insulin treated group (mean 0.84 (SEM 0.01) mmol/1; 2.0 (0.02) mg/100 ml), intermediate in the non-diabetics (mean 0.89 (SEM 0.01) mmol/1; 2.2 (0.02) mg/100 ml), and highest in the non-insulin-treated diabetics (mean 0.95 (SEM 0.02) mmol/1; 2.3 (0.05) mg/100 ml). In all diabetics plasma magnesium concentrations were inversely related to plasma glucose values (rs = -0.33; p less than 0.01) and in non-insulin-treated patients to plasma insulin concentrations (rs = -0.28; p less than 0.05), the former confirming previous observations. In 67 of the diabetics the KG constant for disposal rate of glucose during a standard intravenous glucose tolerance test was directly related to fasting plasma magnesium concentrations, and this relation persisted after controlling for age, sex, body mass index, type of treatment, and glucose and insulin values. This direct relation of plasma magnesium concentration with glucose disposal was unexplained by its influence on insulin secretion but was related to insulin sensitivity; hence magnesium may be an important determinant of insulin sensitivity in maturity onset diabetes.

Blood Glucose↗
PubMed1984

Tissue vanadium levels in manic-depressive psychosis.

The vanadium content of hair, whole blood, serum and urine was estimated by neutron activation analysis in samples from manic patients, depressed patients, recovered manic patients, recovered depressed patients and normal controls. The results suggest that manic patients have significantly raised vanadium levels in hair which fall towards control levels with recovery, but there are no significant differences in the mean vanadium content of whole blood or serum. In contrast, depressed patients have raised levels of vanadium in whole blood and serum which appear to fall with recovery. Levels of vanadium in serum correlate strongly with those in whole blood, but neither shows significant correlation with vanadium in hair for either patients or controls. Hair and blood probably serve as indicator tissues for differing aspects of vanadium metabolism.

Adult↗
PubMed1984

Elevated vanadium content of hair and mania.

Vanadium content of hair from manic patients, recovered patients, and normal controls was measured by neutron activation analysis. The mean vanadium content of the hair of the manic group was significantly higher than that of the control group and that of the group of recovered manics.

Adult↗