Biomedical subjects

W D Ehmann

Publications and source records attributed to W D Ehmann.

12 recordsLinked to original sources

PubMed1992

Brain aluminum in Alzheimer's disease using an improved GFAAS method.

Aluminum (Al) has been determined in autopsy brain samples (20 mg, dry weight) from 10 histologically verified Alzheimer's disease (AD) patients and 10 neurologically normal controls using an improved graphite furnace atomic absorption method. The method makes use of a potassium dichromate matrix modifier to circumvent interferences to the Al determination by the high levels of phosphorus and alkali metals in brain tissue. Brain regions studied included middle frontal gyrus, hippocampus, inferior parietal lobule, and the superior and middle temporal gyri. Small, but significant (p < 0.05) elevations of Al were observed in AD hippocampus, inferior parietal lobule and superior and middle temporal gyri, compared to corresponding control tissues. In contrast to other reports in the literature, no extremely high Al levels (> 20 micrograms/g, dry weight) were observed in our samples. Our highest value for Al in AD brain was 8.0 micrograms/g. These results suggest that there is a small focal increase of Al in specific regions of AD brain compared to age-matched controls. The fact that the increase is small, coupled with the analytical difficulties of accurate bulk sample Al determinations by any technique in the brain matrix, may account for the discordant literature reports for Al in AD brain.

Aged↗

PubMed1990

Trace element imbalances in isolated subcellular fractions of Alzheimer's disease brains.

Concentrations of 13 trace elements (Ag, Br, Co, Cr, Cs, Fe, Hg, K, Na, Rb, Sc, Se, Zn) in isolated subcellular fractions (whole brain, nuclei, mitochondria, microsomes) of temporal lobe from autopsied Alzheimer's disease (AD) patients and normal controls were determined utilizing instrumental neutron activation analysis. Comparison of AD and controls revealed elevated Br (whole brain) and Hg (microsomes) and diminished Rb (whole brain, nuclear and microsomes), Se (microsomes) and Zn (nuclear) in AD. The elevated Br and Hg and diminished Rb are consistent with our previous studies in AD bulk brain specimens. Comparison of element ratios revealed increased Hg/Se, Hg/Zn and Zn/Se mass ratios in AD. Se and Zn play a protective role against Hg toxicity and our data suggest that they are utilized to detoxify Hg in the AD brain. Overall our studies suggest that Hg could be an important toxic element in AD. Whether Hg deposition in AD is a primary or secondary event remains to be determined.

Aged↗

PubMed1990

Trace element imbalances in amyotrophic lateral sclerosis.

Concentrations of 15 elements were determined by instrumental neutron activation analysis in brain, spinal cord, blood cells, serum and nails of Amyotrophic Lateral Sclerosis (ALS) patients and appropriately matched control subjects. Several significant imbalances were detected in trace element levels in ALS samples compared to control samples. Some of these changes are probably secondary to the loss of tissue mass, especially in spinal cord. However the widespread changes observed in Hg and Se levels in ALS tissues deserve special attention. The significance of these alterations in trace element levels in relation to the pathogenesis of ALS is discussed.

Amyotrophic Lateral Sclerosis↗

PubMed1988

Trace element imbalances in hair and nails of Alzheimer's disease patients.

The concentrations of 17 elements in the hair and nails of 180 Alzheimer's disease (AD) and control subjects have been determined by instrumental neutron activation analysis (INAA). Comparisons of trace element levels of properly matched AD and control groups revealed significant imbalances in the concentrations of six elements (Br, Ca, Co, Hg, K, and Zn) between disease and control groups. It is noteworthy that each of these has previously been shown by our group, or others, to be altered in some AD brain region(s). Geometric means for each element in both hair and nails of AD and control subjects are presented, and significant differences noted. The significance of these alterations with regard to the possible role of trace elements in the etiology of AD is discussed.

Aged↗

PubMed1988

Regional brain trace-element studies in Alzheimer's disease.

Alzheimer's disease (AD) brain trace-element imbalances in the amygdala, hippocampus and nucleus basalis of Meynert (nbM) are found in most cases to be consistent with those previously reported in samples derived principally from AD cerebral cortex (Ehmann et al., 1986). The elevation of mercury in AD nbM, as compared to age-matched controls, is the largest trace-element imbalance observed to date in AD brain. In addition to the general confirmation of imbalances for Cs, Hg, N, Na, P, and Rb noted previously in cerebral cortex samples, imbalances for Fe, K, Sc, and Zn were observed in two regions and one region also exhibited imbalances for both Co and Se. Persistent imbalances for the univalent cations Na, K, Rb and Cs support arguments for a membrane abnormality in AD. The data presented here also provide the first comprehensive simultaneous multi-element determinations in both control and AD nbM.

Alzheimer Disease↗

PubMed1986

Brain trace elements in Alzheimer's disease.

Instrumental neutron activation analysis has been used to determine the concentrations of 16 elements in selected brain regions and separated gray- and white-matter specimens from histologically verified Alzheimer's disease (AD) and age-matched control patients. Significantly different (p less than 0.05) mean concentrations of Br, Cl, Cs, Hg, N, Na, P, and Rb were observed in AD bulk brain samples compared to controls, while no significant differences were observed for Ag, Co, Cr, Fe, K, Sb, Sc, and Se. The differences that are most persistent and largest in magnitude for the pooled bulk samples, males and females, left and right hemispheres, and separated gray and white matter are the elevation of Br and Hg and the depletion of Rb in AD compared to controls. Significant interelement correlations for the latter elements in both AD and control brains are also documented. Based on these studies, the possibility of an etiological role for trace elements in AD clearly deserves further investigation.

Aged↗

PubMed1984

Brain trace elements in Pick's disease.

The trace element content of the brain of two patients with Pick's disease examined postmortem was studied using instrumental neutron activation analysis. Results showed significant increases in chlorine, iron, manganese, sodium, and phosphorus and significant decreases in chromium, cesium, rubidium, and selenium and in the mean freeze-dried to wet-weight ratio for patients with Pick's disease compared with control patients. Brain zinc content was not elevated in the two patients, a finding that fails to support the hypothesis that elevated zinc levels play a role in the pathogenesis of Pick's disease.

Aged↗

PubMed1984

Brain trace element concentrations in aging.

Trace element concentrations were determined in various human brain regions over the complete life span using instrumental neutron activation analysis. Several different patterns of trace element alteration were observed with age. Brain Al, Cl and Na concentrations increase with advancing age, while K, P and Rb decline. Ag, Co, Fe, Sb and Sc concentrations increase up to the 40 to 79 age range then decline. Br, Se and Zn remain relatively constant throughout adult life. Hg, Mn and Cs show no consistent trend with age. In infant brains Br and Cl increase and Al, Cr, Cs, Fe, Mn, P, Rb, Sc, Se and Zn decrease compared to adults. The essential elements that remain within narrow concentration limits throughout adult life suggest the presence of an efficient homeostatic mechanism for their regulation in the brain, while those that are altered with age suggest modifications in control mechanisms or altered relationships with other elements. Increased concentrations of non-essential elements may reflect accumulation from our environment, impaired removal or altered balance with other elements.

Adult↗

PubMed1984

Brain manganese concentrations in human aging and Alzheimer's disease.

Manganese levels have been measured in various brain regions in Alzheimer's disease (AD) and aging using instrumental neutron activation analysis. Mn grand mean for all regions was 0.261 micrograms/g for adult controls and 0.245 micrograms/g for AD and the differences were not statistically significant (p less than 0.05). Highest Mn levels were found in the basal ganglia in controls and AD. No significant alterations in Mn were found with advancing age suggesting that the brain has an efficient homeostatic mechanism regulating Mn concentrations. Mn exhibited a significant positive correlation with Fe. Infants had a significantly lower brain Mn level compared to adults.

Adult↗

PubMed1981

Instrumental neutron activation analysis of brain aluminum in Alzheimer disease and aging.

Instrumental neutron activation analysis procedures were used to determine the aluminum content of various brain regions in histologically verified Alzheimer disease (AD) and in controls. The grand mean aluminum level for 74 AD specimens was 0.372 +/- 0.058 microgram/gm and for 137 adult controls, 0.467 +/- 0.033 microgram/gm, both on a wet weight basis. No difference was found at the bulk sample level between AD and adult controls, corrected for age and sex, or when frontal, temporal, and hippocampal specimens were compared. Control specimens (infancy to 85 years) showed an increase in brain aluminum concentration with age. Comparison of freeze-dried to wet weight ratios of AD and controls revealed a small increase in water content in AD brains.

Adolescent↗

PubMedDate not supplied

Trace element content in fingernails and hair of a nonindustrialized US control population.

The concentrations of 17 elements in the nail and hair of 117 subjects from a nonindustrialized environment were determined by instrumental neutron activation analysis (INAA). A new method of statistical treatment that allows for more meaningful use of detection limit values was used to process the concentration data. Geometric means and standard errors are presented for each element, along with a summary of the effects of age, sex, and treatment on the concentration of each element. For nails, these data represent the first comprehensive study for several important elements. Correlations for each element between hair and nail were determined. With few exceptions, concentrations of nonessential trace elements were positively correlated in hair and nail, whereas concentrations of essential elements showed no correlations. The factors affecting concentrations and control levels must be considered in studying alterations in disease states.

Adolescent↗

PubMedDate not supplied

A search for longitudinal variations in trace element levels in nails of Alzheimer's disease patients.

Levels of Br, Hg, K, and Zn were determined by INAA in the nails of Alzheimer's disease (AD) patients at 6-mo intervals for up to 3 yr. These elements have been shown to be imbalanced in AD nail. Bromine showed no trends. Mercury tended to decrease in nail with increasing age of patient, and with the duration and severity of the dementia. Potassium and Zn tended to increase with these same factors. Hence, progressive changes in trace-element levels do occur in AD nail, although imbalances are detected even in the earliest sampled stages of the disease.

Age Factors↗