Biomedical subjects

W D Ehmann

Publications and source records attributed to W D Ehmann.

28 records · Page 2Linked to original sources

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

Trace elements in Alzheimer's disease pituitary glands.

Levels of mercury (Hg), selenium (Se), iron (Fe), rubidium (Rb), and zinc (Zn) were measured in the pituitary gland to assess the possibility of a potential difference in the environmental Hg exposure of Alzheimer's disease (AD) patients and control subjects and levels of other elements of interest in AD. The pituitary gland has been established as a good predictor of environmental Hg exposure. Neutron activation analysis was utilized to determine levels of these elements in pituitary glands of 43 AD subjects and 15 control subjects. No significant differences were observed between the AD and control means for these five elements. The sole significant Pearson's correlation involving Hg was the established correlation with Se, indicative of the detoxification of Hg. The absence of a statistical difference between AD and control pituitary gland Hg levels suggests AD patients do not have an excessive environmental exposure to Hg compared to controls.

Aged↗

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↗

PubMedDate not supplied

Elevated 4-hydroxynonenal in ventricular fluid in Alzheimer's disease.

4-Hydroxynonenal (4-HNE), an aldehyde by-product of the peroxidation of fatty acids, has been shown to have toxic properties for neurons in culture. In light of increasing evidence that oxidative stress contributes to the neurodegenerative process in Alzheimer's disease (AD), we quantified levels of free and protein-bound 4-HNE in the ventricular fluid from 19 AD subjects and 13 control subjects by high-pressure liquid chromatography and dot-blot immunoassay. Free 4-HNE levels were found to be significantly elevated in the ventricular fluid of AD subjects compared with control subjects (p = 0.0096). These results demonstrate increased lipid peroxidation in AD brain and suggest a role for 4-HNE in the neurodegenerative process.

Aged↗