M. V. Aguilar

Cerebrospinal fluid levels of transition metals in patients with Alzheimer's disease

Summary. We compared CSF and serum levels of iron, copper, manganese, and zinc, measured by atomic absorption spectrophotometry, in 26 patients patients with Alzheimers disease (AD) without major clinical signs of undernutrition, and 28 matched controls. CSF zinc levels were significantly decreased in AD patients as compared with controls (p < 0.05). The serum levels of zinc, and the CSF and serum levels of iron, copper, and manganese, did not differ significantly between AD-patient and control groups. These values were not correlated with age, age at onset, duration of the disease, and scores of the MiniMental State Examination in the AD group. Weight and body mass index were significantly lower in AD patients than in controls. Because serum zinc levels were normal, the possibility that low CSF zinc levels were due to a deficiency of dietary intake seems unlikely. However, it is possible that they might be related to the interaction of beta-amyloid and/or amyloid precursor protein with zinc, that could result in a depletion of zinc levels.

Cerebrospinal fluid levels of transition metals in patients with Parkinson's disease.

Summary. We compared CSF and serum levels of iron, copper, manganese, and zinc, measured by atomic absorption spectrophotometry, in 37 patients with Parkinsons disease (PD) and 37 matched controls. The CSF levels of zinc were significantly decreased in PD patients as compared with controls (p < 0.05). The serum levels of zinc, and the CSF and serum levels of iron, copper, and manganese, did not differ significantly between PD-patient and control groups.There was no influence of antiparkinsonian therapy on CSF levels of none of these transition metals. These values were not correlated with age, age at onset, duration of the disease, scores of the Unified Parkinson Disease Rating Scale of the Hoehn and Yahr staging in the PD group, with the exception of CSF copper levels with the duration of the disease (r = 0.38, p < 0.05). These results suggest that low CSF zinc concentrations might be related with the risk for PD, although they could be related with oxidative stress processes.

Plasma Mineral Content in Type-2 Diabetic Patients and Their Association with the Metabolic Syndrome

Background: Metabolic syndrome is a clinical disorder that is becoming more prevalent in Spain. The syndrome encompasses a set of metabolic disorders such as type-2 diabetes mellitus, hypertension, dyslipidemia, and obesity, which may be associated with variations in serum levels and poor delivery of certain mineral elements. Methods: This study attempted to ascertain whether metabolic syndrome might be linked to alterations in serum levels of the mineral elements magnesium, copper, zinc, chromium, and nickel in a population of 92 diabetic subjects, some suffering from certain conditions associated with the metabolic syndrome, and 72 control subjects (Hospital Príncipe de Asturias, Alcalá de Henares, Spain). Results: The results indicated that as a group the alterations implicated in metabolic syndrome were indeed associated with variations in blood levels of the mineral elements considered, though statistically significant differences were recorded only in the case of copper. Still, trends in mineral levels for each of the separate components contributing to the syndrome tended to increase. Conclusion: Metabolic complications appear to be associated with alterations in the levels of some minerals, especially copper.

Cerebrospinal fluid levels of selenium in patients with Alzheimer's disease

Summary. We compared CSF and serum selenium levels, measured by atomic absorption spectrophotometry, in 27 patients with Alzheimers disease (AD) (13 females, 14 males, mean ± SD age 73.6 ± 7.4 years) without major clinical signs of undernutrition, and 34 matched controls (18 females, 16 males, mean ± SD age 70.7 ± 7.8 years). CSF and serum selenium levels did not differ significantly between AD-patient (11.4 ± 7.8 ng/ml and 28.5 ± 13.0 ng/ml, respectively) and control groups (13.3 ± 7.0 ng/ml and 22.5 ± 17.5 ng/ml). These values were not correlated with age, age at onset, duration of the disease, and scores of the MiniMental State Examination in the AD group. Weight and body mass index were significantly lower in AD patients than in controls. These results suggest that CSF selenium concentrations are apparently unrelated with the reported oxidative stress processes in patients with AD.

Cerebrospinal fluid selenium and chromium levels in patients with Parkinson's disease.

Summary. We compared CSF and serum levels of selenium and chromium, measured by atomic absorption spectrophotometry, in 28 patients with Parkinsons disease (PD) and 43 matched controls. The CSF and serum levels of these trace metals did not differ significantly between PD patients and controls. CSF selenium and chromium levels were not correlated with age, age at onset, duration of the disease, scores of the Unified Parkinson Disease Rating Scale of the Hoehn and Yahr staging in the PD group. Although antiparkinsonian therapy did not influence significantly the CSF levels of selenium, PD patients not treated with levodopa had significantly higher CSF selenium levels than controls (p < 0.01). It is possible that increased CSF selenium levels could indicate an attempt of protection against oxidative stress. The normality of CSF and serum chromium levels suggest that these values are not related with the risk for PD.

Effects of Arsenic (V)-Chromium (III) Interaction on Plasma Glucose and Cholesterol Levels in Growing Rats

Recent studies have demonstrated interaction between arsenic (As) and chromium (Cr) affecting absorption and/or protein catabolism. In the present study the possible effects of As(V)/Cr(III) interaction on growth rate, organ weight, and the two main organic functions of Cr, i.e., regulation of plasma glucose levels and total plasma cholesterol levels, was examined in weaned male Wistar rats. The diet of 20 rats was supplemented with 5 micrograms of As(V) and/or Cr(III) per gram of food for 10 weeks. As/Cr interaction did not significantly affect growth rates on organ weight:body weight ratios but did decrease total plasma cholesterol levels, though the decrease was not as pronounced as in the group supplemented with Cr alone (p < 0.1). Since supplementation with As(V) produced the opposite effect (96.83 vs. 47.27) (p < 0.01), the combined use of As and Cr may prove beneficial in cases of chronic As(V) intoxication. Supplementation treatment with As(V) and Cr(III) combined had no significant effect on glucose levels, because though As(V) affects Cr tissue levels and thus alters the effect of Cr on plasma cholesterol levels, individual effects of As(V) and Cr(III) are similar, and hence basal glucose levels are unaffected.

Effect of Diabetes on the Tissular Zn/Cu Ratio

One of the parameters related to the development of coronary disease in diabetic patients is the tissular Zn/Cu ratio. We evaluated the levels of Zn and Cu, and the Zn/Cu ratio in insulin target tissues in diabetic and normoglucemic growing Wistar rats in order to determine the influence of diabetes and the disease evolution period. Diabetes was induced chemically by administration of streptozotocin. In order to determine the influence of the duration of diabetes on the Zn/Cu ratio, three time periods were studied: 7, 21 and 60 days. The animals were subsequently sacrificed and the target tissues (liver, adipose tissue, and skeletal muscle) were removed. Zn and Cu levels were measured by AAS after wet mineralization. STZ-induced diabetes modified the tissular Zn and Cu content. There was a significant decrease (p < 0.01) in liver and adipose tissue, but not in skeletal muscle. The in adipose tissue and skeletal muscle, but not in liver, effects were dependent on the duration of diabetes. The Cu content was higher in the liver of diabetic rats (p < 0.1) and lower in adipose tissue (p < 0.1) and skeletal muscle (NS). Tissular Cu levels also were affected significantly by the duration of diabetes. The Zn/Cu ratio showed a generalized decrease, except in skeletal muscle. This decrease was dependent on the presence of diabetes mellitus and the duration of the disease (p < 0.01).

Mechanisms of absorption of As2O5, from rat small intestine : The effect of different parameters

The main purpose of this research was to study the effects of water movement on arsenic absorption. In order to appreciate and measure the interaction between these two variables we investigated the perfusion of isotonic and hypotonic buffers (containing 3.2 microgram/ml As2 O5 into rat small intestines. The As (V) depended on osmolarity sensitive. This implied the presence of a saturable uptake kinetic mechanism and suggested the participation of some kind of carrier-mediated transport system. An increase in arsenate absorption and its accumulation in organs was detected in the presence of an Na+ gradient. The same technique, combining isotonic buffers with different pH values and buffers containing valinomycin, was used in order to study the effects of intraluminal pH on membrane potential. A significant decrease in arsenic levels and As(V) absorption in organs was detected as a result of an increase in the pH. This influence of pH on the As(V) absorption mechanism indicated dependence on a proton (H+) gradient. An inside negative potassium potential induced by valinomycin increased significantly the uptake of arsenate, suggesting an electrogenic transport of arsenate. In conclusion, the As(V) might be absorbed from the small intestine through a carrier-mediated mechanism, which would depend on the Na+(-) and H+(-)gradients and the membrane potential differential from both sides of the intestinal epithelial cells.

Determination of chromium in cerebrospinal fluid using electrothermal atomisation atomic absorption spectrometry.

A rapid method to determine the chromium content of cerebrospinal fluid (CSF) samples using electrothermal atomization atomic absorption spectrometry (ETA-AAS) with deuterium-arc background correction is described. The chromium concentration in CSF was evaluated by the standard addition method. Sample dilution (1 + 1) with 0.25% (m/v) Triton X-100 and 4.5% (v/v) HNO3 gave the best combination of sensitivity, reproducibility, and low blank reading compared with dilution using other solvents. Within-batch reproducibility was 3.2% for 20 CSF samples, between-batch reproducibility was 4.7%. CSF samples from 43 healthy volunteers collected in a manner designed to avoid contamination yielded chromium concentrations of 14.6 +/- 6.3 ng mL(-1).

Effect of chronic Cr3+ administration and its interaction with dietary As3+ on glucose tolerance in wistar rats.

Abstract Forty-nine male rats were divided into seven groups of seven rats for a two month study of the effects of chronic Cr 3+ and As 3+ consumption on glucose tolerance. Five groups received organic or inorganic Cr 3+ and/or As 3+ in their drinking water, one group was fed a special Cr-free diet and the control group was fed the same feed as the first five groups and distilled water ad libitum . Glucose tolerance and insulin levels were determined at two months. The parameter total blood glucose concentration TBGC, which was based on basal glucose, glucose curve displacement with respect to the control curve, time of the maximum blood glucose concentration and the area under the curve, was used to assess the data. The Cr 3+ groups presented contrasting effects depending on whether they had received organic or inorganic Cr 3+ and of the presence of As 3+ . The effect of organic Cr 3+ alone was hyperglycemic, while the effect of the inorganic Cr 3+ alone was hypoglycemic. The effects of the As 3+ alone and of the Cr-free diet were also hypoglycemic.