silicon and Dementia

Topics: Acetylcholine; Acetylcholinesterase; Age Factors; Aged; Aluminum; Alzheimer Disease; Amyloid; Amyloid beta-Peptides; Brain; Brain Chemistry; Cell Count; Cognition; Craniocerebral Trauma; Delirium; Dementia; Diagnosis, Differential; Female; Humans; Interpersonal Relations; Male; Memory; Middle Aged; Neurofibrils; Neurotransmitter Agents; Personality; Sex Factors; Silicon; Thyroid Diseases; Tomography, Emission-Computed

Serum aluminium was significantly raised (p < 0.01) up to 2-3-fold, in patients with dementia including Alzheimers Disease (AD) 0.66 +/- 0.2 (mumol/l mean +/- 1 s.d.) and patients on regular aluminium hydroxide therapy 0.54 +/- 0.17, compared with healthy volunteers 0.21 +/- 0.13, although not as high as in patients with end stage renal failure on regular dialysis 0.88 +/- 0.42. The urine outputs (mumol/l mean +/- 1 s.d.) of aluminium and silicon, respectively, were also significantly increased up to 5-fold in dementia 2.89 +/- 1.78 (n = 23) and 1587 +/- 645 (n = 22) and patients on regular aluminium hydroxide therapy 5.03 +/- 2.08 (n = 8) and 998 +/- 364 (n = 21) compared with healthy volunteers 0.95 +/- 0.82 (n = 84) and 471 +/- 332 (n = 114). The increase in urine aluminium was thus associated with a similarly marked increase in the output of silicon. The increased absorption of aluminium in dementia patients is equivalent to the intestinal loading in Aludrox therapy. Also silicon appears to be important in the renal excretion of the absorbed aluminium. Whether this is a phenomenon related to the elderly or the process of dementia warrants further study.

Topics: Adult; Aged; Aged, 80 and over; Aging; Aluminum; Aluminum Hydroxide; Alzheimer Disease; Case-Control Studies; Dementia; Diet; Drug Combinations; Female; Humans; Intestinal Absorption; Kidney Failure, Chronic; Magnesium Hydroxide; Male; Middle Aged; Renal Dialysis; Silicon

To investigate the relation of aluminum and silicon in drinking water to risk of Alzheimer's disease, we carried out a case-control study in eight regions of England and Wales. Subjects were identified from the records of neuroradiology centers, and diagnoses were confirmed by a review of hospital case-notes. Exposure to aluminum and silicon in drinking water was estimated from residential histories of 106 men with Alzheimer's disease, 99 men with other dementing illnesses, 226 men with brain cancer, and 441 men with other diseases of the nervous system. All subjects in the study were between 42 and 75 years of age. There was little association between Alzheimer's disease and higher aluminum or lower silicon concentrations in drinking water when cases were compared with any of the control groups. The results indicate that any risk of Alzheimer's disease from aluminum in drinking water at concentrations below 0.2 mg per liter is small, and they give no support for a protective role of silicon.

Topics: Adult; Aged; Aluminum; Alzheimer Disease; Brain Neoplasms; Case-Control Studies; Dementia; England; Humans; Male; Middle Aged; Risk Factors; Silicon; Wales; Water Pollutants; Water Supply

Topics: Aluminum; Amyotrophic Lateral Sclerosis; Calcium; Dementia; Guam; Hippocampus; Histocytochemistry; Humans; Neurons; Parkinson Disease; Silicon

We designed a prospective study to determine whether CSF silicon elevation is specific for Alzheimer-type dementia (ATD) and whether it is related to the severity of cognitive or functional impairment. We found elevated CSF silicon in 30% of 23 ATD patients but in only 1 of the 23 age-matched nondemented controls. In all ATD patients with elevated CSF silicon, symptoms began after age 65. Thirty-four percent of 29 patients with other types of dementia also had elevated CSF silicon. Therefore, elevated CSF silicon concentrations are not specific for ATD, but they correlate with age and severity of functional impairment in late-onset ATD.

Topics: Adult; Age Factors; Aged; Alzheimer Disease; Dementia; Humans; Middle Aged; Prospective Studies; Silicon

We analyzed multiple trace elements in tap water, dialysis fluids, and CSF of patients on dialysis and with chronic renal insufficiency. Before placement of a deionizer in the dialysis unit, we found elevated levels of aluminum, barium, copper, silicon, and zinc in tap water and dialysis fluids. These were corrected by the deionizer. CSF silicon content was increased in patients with chronic renal insufficiency and on dialysis; CSF aluminum, barium, copper, and zinc were normal.

Topics: Adult; Aged; Dementia; Humans; Kidney Diseases; Middle Aged; Renal Dialysis; Silicon; Trace Elements

Using inductively coupled argon plasma emission spectroscopy, we measured 19 trace elements in cerebrospinal fluid of 265 patients who were undergoing diagnostic lumbar puncture. Thirty-three patients had Alzheimer-type dementia (ATD); 16 patients had other dementing illnesses; and 20 had no neurologic disease. There were seven cases of autopsy-proven Alzheimer's disease (AD) and eight autopsy controls. We found elevated CSF silicon in 24% of ATD and 71% of AD patients. We found no relationship between CSF aluminum, arsenic, lead, or manganese and ATD, AD, or other dementing illnesses.

Topics: Aged; Alzheimer Disease; Dementia; Female; Humans; Male; Middle Aged; Silicon; Trace Elements; Zinc

The elemental content of neurons of the hippocampus was studied by a combination of scanning electron microscopy and x-ray spectrometry in autopsy-derived brain tissue from three cases of senile dementia (Alzheimer type) and three nondemented elderly controls. Foci of aluminum were detected within the nuclear region of a high percentage of neurons containing neurofibrillary tangles from the cases of senile dementia as well as the elderly controls. The adjacent normal-appearing neurons from both groups of patients were virtually free of detectable aluminum. These findings suggest that the association of aluminum to Alzheimer's disease extends to the neuronal level.

Topics: Aluminum; Alzheimer Disease; Cell Nucleus; Dementia; Electron Probe Microanalysis; Hippocampus; Humans; Magnesium; Microscopy, Electron, Scanning; Neurofibrils; Silicon

Electron probe microanalysis demonstrates the presence of aluminum, calcium, phosphorus and silica in senile plaques in the cerebral cortex of 4 patients. Our findings are reported here with the reservation tnat the tissues were fixed before examination.

Topics: Aluminum; Alzheimer Disease; Brain; Brain Chemistry; Calcium; Dementia; Humans; Microscopy, Electron; Phosphorus; Silicon

Topics: Aged; Aging; Alzheimer Disease; Body Fluids; Brain; Dementia; Female; Humans; Kidney; Liver; Male; Middle Aged; Myocardium; Nails; Silicon; Spleen

Topics: Adult; Aged; Aging; Brain Chemistry; Calcium; Cerebral Cortex; Dementia; Down Syndrome; Humans; Iron; Neuroglia; Phosphorus; Silicon; Viral Plaque Assay

Topics: Adult; Aged; Cerebral Cortex; Dementia; Female; Histocytochemistry; Humans; Microscopy, Electron; Silicon; Staining and Labeling; Temporal Lobe