Levels of lead, cadmium, copper, iron, and zinc in deciduous teeth of children living in Irbid, Jordan by ICP-OES: some factors affecting their concentrations.

The aim of this study was to measure the concentrations of lead (Pb), cadmium (Cd), copper (Cu), iron (Fe), and zinc (Zn) in deciduous teeth from children living in Jordan and to investigate the affecting factors. Deciduous teeth samples (n = 320, without fillings) were collected from 5- to 12-year-old children and analyzed for Pb, Cd, Cu, Fe, and Zn using inductively coupled plasma-optical emission spectrometry. A questionnaire was used to gather information on each child, such as sex, age, tooth type (incisors, canines, and molars), tooth position within the mouth (upper or lower jaw), caries status, presence of amalgam fillings inside the mouth, type of drinking water (tap water, home purified water, and plant purified water), and zone of residence (close to or far from heavy traffic roads). The mean concentrations of Pb, Cd, Cu, Fe, and Zn were 30.26, 0.55, 6.23, 34.72, and 128.21 µg/g, respectively. Our results indicate that there is a clear relation between the concentrations of the metals analyzed in this study and tooth type, tooth position within the mouth, caries status, presence of amalgam fillings inside the mouth, and type of drinking water. No significant differences in the concentrations of the five metals analyzed were observed due to sex. Our results also show that no significant difference among Pb, Cd, Cu, Fe, and Zn concentrations and age among the ages of 5-6, 7-8, 9-10, and 11-12, except for Pb, which decreases at age 11-12.

Garlic (Allium sativum L.) as a potential antidote for cadmium and lead intoxication: cadmium and lead distribution and analysis in different mice organs.

Analysis and distribution of Pb and Cd in different mice organs including liver, kidney, spleen, heart and blood were evaluated after treatment with different aqueous concentrations of garlic (12.5-100 mg/l). Atomic absorption spectrometry (AAS) was used for analysis of Pb and Cd in these organs. Treatment of Cd-Pb exposed mice with garlic (12.5-100 mg/l) reduced Pb concentrations by 44.65, 42.61, 38.4, 47.56, and 66.62% in liver, kidney, heart, spleen and blood respectively. Moreover, garlic reduced Cd levels by 72.5, 87.7, 92.6, 95.6, and 71.7% in liver, kidney, heart, spleen and blood respectively. The suppressed immune responses in mice pretreated with Cd-Pb mixture were reversed by 48.85, 55.82, 81.4 and 90.7 in the presence of 100, 50, 25, and 12.5 mg/ml of garlic extract.

Lead and cadmium in human teeth from Jordan by atomic absorption spectrometry: Some factors influencing their concentrations.

The aim of this study was to measure the concentrations of lead (Pb) and cadmium (Cd) in human teeth and to investigate the affecting factors. Teeth samples (n = 268) were collected from people living in different cities in Jordan including Amman, Zarqa, Al-Mafraq and Irbid and analyzed for Pb and Cd using atomic absorption spectrometry (AAS). A questionnaire was used to gather information on each person, such as age, sex, place where the patient lives, smoking, presence of amalgam fillings inside the mouth, and whether the patient uses toothpaste or not. The mean concentrations of Pb and Cd were 28.91 microg/g and 0.44 microg/g, respectively. The results indicate that there is a clear relation between Pb and Cd concentrations and the presence of amalgam fillings, smoking, and place of living. Pb was sex-dependent, whereas Cd was not. Our results show that Pb and Cd concentrations in samples obtained from Al-Mafraq and Irbid are higher than those obtained from Amman and Zarqa. Pb was highest in Mafraq, whereas Cd was highest in Irbid. The Pb and Cd concentrations in teeth from smokers (means: Pb = 31.89 microg/g, Cd = 0.49 microg/g) were significantly higher than those from nonsmokers (means: Pb = 24.07 microg/g, Cd = 0.37 microg/g). Pb and Cd concentrations in teeth of patients with amalgam fillings (means: Pb = 31.02 microg/g and Cd = 0.52 microg/g) were significantly higher than those from patients without amalgam fillings (means: Pb = 26.87 microg/g and Cd = 0.41 microg/g). Our results show that brushing the teeth daily with toothpaste does not significantly decrease the concentration of both Pb and Cd. The mean concentrations of Pb and Cd do not vary significantly between the ages 20-30, 31-40, and 41-50, but both increased rapidly at age 51-60.

Neurosteroid analysis.

In this chapter, we review techniques used for the analysis of neurosteroids and discuss the advantages and disadvantages of each method. Because radioimmunoassay (RIA) procedures are well known, we focus more on the relatively recent mass spectrometric methods used for analyzing neurosteroids and their sulfates. We also discuss some promising methods that permit the detection of low levels of neurosteroids in small samples with a minimum number of sample pretreatment procedures. Lowering the limits of detection will enable a better understanding of the physiological function of neurosteroids and the mechanism(s) for neurosteroid regulation of brain function. Moreover, analyzing low levels of neurosteroids more efficiently will increase the throughput, which is important for clinical analysis. Initially, most neurosteroid analyses were performed by RIA. However, many analyses of neurosteroids are now performed by mass spectrometry. To date, the most sensitive, specific, and accurate method for the simultaneous analysis of several neurosteroids is the method of gas chromatography/electron capture/negative chemical ionization mass spectrometry. This method, with its many variants, is described in detail.

Gas phase hydrogen deuterium exchange reactions of a model peptide: FT-ICR and computational analyses of metal induced conformational mutations.

We utilized gas phase hydrogen/deuterium (H/D) exchange reactions and ab initio calculations to investigate the complexation between a model peptide (Arg-Gly-Asp[triple bond]RGD) with various alkali metal ions. The peptide conformation is drastically altered upon alkali metal ion complexation. The associated conformational changes depend on both the number and type of complexing alkali metal ions. Sodium has a smaller ionic diameter and prefers a multidentate interaction that involves all three amino acids of the peptide. Conversely, potassium and cesium form different types of complexes with the RGD. The [RGD + 2Cs - H]+ species exhibit the slowest H/D exchange reactivity (reaction rate constant of approximately 6 x 10(-13) cm3molecule(-1)s(-1) for the fastest exchanging labile hydrogen with ND3). The reaction rate constant of the protonated RGD is two orders of magnitude faster than that of the [RGD + 2Cs - H]+. Addition of the first cesium to the RGD reduces the H/D exchange reaction rate constant (i.e., D0) by a factor of seven whereas sodium reduces this value by a factor of thirty. Conversely, addition of the second alkali metal ions has the opposite effect; the rate of D0 disappearance for all [RGD + 2Met - H]+ species (Met[triple bond]Na, K, and Cs) decreases with the alkali metal ion size.