Atomic absorption spectrometry of trace metals in clinical pathology

Involvement of essential trace elements in the pathogenesis of hepatitis C virus‑related chronic liver disease and nonalcoholic steatohepatitis

Essential trace elements are involved in the pathogenesis of chronic liver disease (CLD), which causes hepatic inflammation, steatosis and fibrosis. The present study investigated the roles of essential trace elements in the pathogenesis of hepatitis C virus-related CLD (CLD-C) and nonalcoholic steatohepatitis (NASH), and compared the levels of these trace elements between the two groups. Serum zinc (Zn), selenium (Se), copper (Cu) and ferritin levels were measured in patients with CLD-C (n=66) and NASH (n=26). Subsequently, the correlations between the levels of these essential trace elements in patient sera and the biochemical or pathological parameters of patients with CLD-C and NASH were determined. The results demonstrated that the serum ferritin levels were significantly correlated with serum alanine aminotransferase levels in both the CLD-C and NASH groups. In both groups, the serum Zn and Se levels were significantly associated with serum albumin levels, and inversely associated with the stages of hepatic fibrosis. Furthermore, serum ferritin levels were positively associated, and serum Zn levels were inversely correlated with the grades of hepatic steatosis in patients with CLD-C, whereas serum Se levels were closely associated with the grades of hepatic steatosis only in patients with NASH. In both groups, serum ferritin levels were positively correlated, and serum Zn levels were inversely correlated with homeostasis model for the assessment of insulin resistance (HOMA-IR) values, and serum Se was negatively correlated with the HOMA-IR values in patients with CLD-C only. In conclusion, these results indicated that the involvement of essential trace elements in insulin resistance and hepatic steatosis may differ slightly between patients with CLD-C and those with NASH.

Evaluation of zinc level in skin of patients with necrolytic acral erythema

BACKGROUND

Necrolytic acral erythema (NAE) is considered a cutaneous sign of hepatitis C virus infection. Its exact pathogenesis is still not fully understood, with some reports about decreased serum zinc levels but none about its level in the skin.

OBJECTIVES

To assess skin (lesional and perilesional) and serum zinc levels in patients with NAE and compare them with levels in control subjects.

METHODS

Fifteen patients with NAE and 10 healthy controls were included in this study. Assessment of zinc level, in serum by graphite furnace atomic absorption spectrophotometry and in lesional and perilesional skin biopsies by flame atomic absorption spectrometry, was done in all subjects. Re-evaluation of serum and lesional skin zinc level was done after oral zinc treatment.

RESULTS

Mean±SD zinc levels were significantly lower in patients (serum 0·44 ± 0·13 mg L(-1) ; lesional skin 42·6 ± 18·9 mg L(-1) ; perilesional skin 32·5 ± 17·2 mg L(-1) ) than controls (serum 1·17 ± 0·29 mg L(-1) ; skin 100·1 ± 2·77 mg L(-1) ), with a positive correlation between lesional and perilesional skin zinc (r = 0·91, P < 0·01). Oral zinc supplementation significantly increased serum and skin zinc levels (by 159% and 4%, respectively; P < 0·05).

CONCLUSIONS

NAE is associated with decreased serum and skin zinc levels. Oral zinc supplementation corrects decreased levels of plasma and skin zinc much earlier than the desired clinical benefits appear.

Determination of cadmium, cobalt, copper, iron, manganese, and zinc in thyroid glands of patients with diagnosed nodular goitre using ion chromatography

The aim of this study was to estimate and compare the contents of selected metals in 65 pathological (diagnosed nodular goitre) and 50 healthy human thyroid tissues (taken during autopsies). Ion chromatography (IC) preceded by microwave mineralization was applied for the first time for determination of cadmium, cobalt, copper, iron, manganese, and zinc in human thyroid samples. The study proved that the concentrations of Cu(2+), Mn(2+), Fe(3+), and Zn(2+) were significantly higher in the control group (healthy thyroids) in comparison with the studied group (nodular goitre) (p<0.05), whereas for Co(2+) the difference between two means of concentration (healthy vs pathological thyroids) was not significant statistically at 0.05 significance level. Measurement accuracy was verified by measurements of NIST standard reference material (1566a Oyster Tissue). Very good precision (RSD below 5%) and recoveries (above 90%) were evaluated.

Effect of total plasma homocysteine on cervical dysplasia risk

We investigated whether total plasma homocysteine (tHcy) is associated with risk for cervical intraepithelial neoplasia (CIN). tHcy was evaluated, along with numerous risk factors for CIN and biochemical indexes of nutrients, in a previously reported study population of 294 subjects with CIN and 170 female controls without CIN. tHcy was significantly higher in cases than in controls (9.1 vs. 8.3 mumol/l, p = 0.002). Human papillomavirus type 16 infection [odds ratio (OR) = 6.7], oral contraceptive use (OR = 6.0), parity (OR = 2.2), and cigarette smoking (OR = 1.9) were significantly associated with CIN after adjustment for each other and for age, number of sexual partners, and plasma tHcy, folate, iron, and zinc. Human papillomavirus type 16 positivity increased risk for CIN more when tHcy was > 9.12 mumol/l (OR = 4.7) than when it was < or = 9.12 mumol/l (OR = 3.0). Cigarette use increased risk for CIN when tHcy was > 9.12 mumol/l (OR = 3.9), but not when tHcy was < or = 9.12 mumol/l (OR = 1.5). Parity increased risk for CIN more when tHcy was > 9.12 mumol/l (OR = 4.0) than when tHcy was < or = 9.12 mumol/l (OR = 2.0). These results suggest that elevated plasma tHcy is a risk factor for cervical dysplasia and that it enhances the effects of other risk factors. It is unknown whether tHcy is serving as a marker of folate deficiency or is acting through other mechanisms.

Measurement of testosterone and pregnenolone in nails using gas chromatography-mass spectrometry

An efficient method for the determination of testosterone and pregnenolone in human nails using gas chromatography-mass spectrometry (GC-MS) with d3-testosterone as an internal standard is described. The method involves alkaline digestion and liquid-liquid extraction, with subsequent conversion to mixed pentafluoropenyldimethylsilyl-trimethylsilyl (flophemesyl-TMS) derivatives for sensitive analysis in the selected-ion monitoring (SIM) mode. The limit of detection (LOD) and limit of quantification (LOQ) were lowered to 0.1 and 0.2 pg/g, respectively, when 100 mg of nail-clippings were used. The mean recoveries of testosterone and pregnenolone were 89.8 and 86.7%, respectively, while good overall precision (% C.V.; 4.5-9.5) and accuracy (% bias; 3.9-8.4) were demonstrated. Linearity as a correlation coefficient was 0.9913 (testosterone) and 0.9965 (pregnenolone). When applied to fingernail and toenail samples from seven healthy men and nine healthy women, testosterone and pregnenolone were positively detected in the concentration range of 0.24-5.80 ng/g. The levels of two steroids studied in the nails were found to be higher in the male subjects than in the female subjects, and except for the toenails of the females, the levels of testosterone were higher than those of pregnenolone.

Correlates of total plasma homocysteine: folic acid, copper, and cervical dysplasia

We examined correlates of total plasma homocysteine (tHcy) in 294 subjects with cervical intraepithelial neoplasia and 170 control subjects. Associations of tHcy with risk factors for cervical intraepithelial neoplasia and 24-h intakes and biochemical indices of nutrients were examined. Plasma and red blood cell folate and plasma B(12) were strong inverse correlates of tHcy (r = -0.35, -0. 31, and -0.27, respectively). Plasma copper and severity of dysplasia were positively correlated with tHcy (r = 0.14 and 0.21, respectively). A stepwise regression model that included red blood cell folate, plasma copper, grade of dysplasia, ethnicity, intake of polyunsaturated fatty acids, plasma vitamin B(12), intake of fat, and oral contraceptive use explained 29% of the variation in tHcy. Two hundred thirty-five subjects with cervical intraepithelial neoplasia were randomized to receive folic acid (10 mg/d) or placebo for 6 mo. After 2, 4, and 6 mo, mean tHcy in the folate-supplemented group (7.2 +/- 1.8, 7.0 +/- 1.9, and 7.0 +/- 2.3 micromol/L, respectively) was significantly lower than baseline and the placebo group at 2, 4, and 6 mo (8.9 +/- 3.1, 8.4 +/- 3.0, and 8.9 +/- 3.1 micromol/L, respectively). Supplementation lowered tHcy even in subjects in the highest quintile of baseline folate. Folate, vitamin B(12), copper, and severity of dysplasia are associated with tHcy. Folate supplementation significantly lowers tHcy even in folate-replete subjects.

The association between specific nutritional antioxidants and manifestation of colorectal cancer

Determination of specific antioxidants for examination of oxidative balance and immune responses may be of value in the early diagnosis of colorectal cancer. In the present report, we investigated urinary excretion of zinc, copper, and neopterin and serum levels of vitamins A, C, and E in 30 patients (age = 64 +/- 12 y) with colorectal cancer at the time of diagnosis and in 30 control subjects (age = 61 +/- 11 y) with benign disorders not associated with a systemic inflammatory response. Urinary excretion of zinc, copper, and neopterin was significantly elevated, and serum concentration of vitamin A was decreased in patients with colorectal cancer; these changes are characteristics of systemic immune activation. These phenomena may be of use for the detection of tumor progression and immune response to neoplasm.

Increased urinary zinc excretion in cancer patients is linked to immune activation and renal tubular cell dysfunction

Urinary zinc excretion is known to be increased in cancer patients, but the pathogenesis of this phenomenon remains uncertain. Both skeletal muscle catabolism and renal tubular cell dysfunction have been proposed to explain this observation. We have investigated urinary zinc and N-acetyl-beta-D-glucosaminidase (NAG), an indicator of renal tubular cell dysfunction, as well as serum neopterin, an index of systemic immune activation, in 22 patients with cancer and seven controls. Both serum neopterin and urinary zinc were significantly elevated in cancer patients (15.8 +/- 12.7 versus 7.3 +/- 2.3 nmol l-1 and 1.77 +/- 0.80 versus 1.21 +/- 0.41 mmol mol-1 creatinine, P < 0.02 and P < 0.05, respectively), while NAG was similar in cancer patients and the controls (13.58 +/- 13.80 versus 13.68 +/- 12.19 mu kat mol-1 creatinine). A significant correlation was observed between serum neopterin and urine zinc (rs = 0.5119, P < 0.02), serum neopterin and urine NAG (rs = 0.6761, P < 0.002), and urinary zinc and NAG (rs = 0.6348, P < 0.002). In conclusion, the present data indicate a link between urinary zinc excretion and immune activation as well as renal tubular cell dysfunction. In addition, renal tubular cell dysfunction appears to be linked to immune activation.

Association between renal tubular cell dysfunction and increased urinary zinc excretion in cancer patients

Although an increase in renal zinc excretion in cancer patients is well documented, the mechanisms involved are still disputed. As recent studies have raised the question of the role of renal tubular cell dysfunction in the elevation of urinary zinc output, we have examined urinary zinc excretion and the excretion of N-acetyl-beta-D-glucosaminidase (NAG), an indicator of tubular cell dysfunction, in 30 patients with cancer, 28 healthy controls and 20 patients with benign non-inflammatory disorders. As expected, urinary zinc excretion was significantly higher in the cancer patients compared with controls and patients with benign disorders (2.64 +/- 3.05 vs. 0.86 +/- 0.36 and 0.89 +/- 0.29 mmol mol creatinine-1, p < 0.001). NAG activity was also elevated (18.9 +/- 20.1 vs. 4.32 +/- 3.33 and 9.99 +/- 9.72 mukat mol creatinine-1, p < 0.001 and p < 0.05, respectively). A significant correlation between urine zinc and NAG was observed in all three groups (rho = 0.73, p < 0.001, rho = 0.55, p < 0.01 and rho = 0.45, p < 0.05, respectively). In conclusion, our data provide additional support for the role of renal tubular cell dysfunction in hyperzincuria in cancer. Urinary zinc measurement may represent an alternative approach to detecting renal tubular dysfunction in human pathology.

Predictive inability of cord zinc, magnesium and copper levels on the development of benign hyperbilirubinemia in the newborn

Cord serum concentrations of zinc, magnesium and copper were determined in 90 healthy term infants. The infants were divided by peak bilirubin values into an icteric group (peak bilirubin > 136 mumol/l) (n = 21) and a control group (peak bilirubin < or = 136 mumol/) (n = 69). Mean cord serum zinc, magnesium and copper concentrations in the icteric group did not differ from those of the control group. Furthermore, no significant correlation was found between peak serum bilirubin concentrations and cord serum concentrations of these three elements. We conclude that cord serum concentrations of zinc, magnesium or copper are not useful in predicting which neonates will develop hyperbilirubinemia.

Effects of nickel-chrome dental alloys used in dentistry on saliva and serum nickel levels, peripheral T-lymphocytes and some other blood parameters

Epidemiological investigations have shown that nickel is a potent sensitivity producing agent. However, it is not known if intra-oral use of nickel-chrome alloys can cause any sensitization reaction. The purpose of this study was to determine if nickel-chrome alloys used in dentistry influence nickel levels in saliva and serum and whether there were associated changes of some blood parameters such as lymphocyte, T-lymphocyte, neutrophil, eosinophil, basophil and monocyte. The study was performed on 10 patients all of whom had no medical and dental history of using nickel containing drugs or restorations. Four unit fixed partial prostheses containing 22.97% nickel and 22.65% chrome were constructed and worn by the patients. Blood and unstimulated whole saliva samples were taken from the patients before insertion of the prostheses and then 1 month and 6 months post-insertion. Hematocrit determinations, total and differential leucocyte count, total T-lymphocyte counts and serum nickel concentrations were determined from the blood samples and salivary nickel concentrations from the saliva samples. It was found that there were no significant changes in circulating T-lymphocyte and monocyte population but a decrease was found in circulating eosinophil and an increase in circulating neutrophil and basophil populations.

Determination of zinc and copper in urine using Zeeman effect flame atomic absorption spectroscopy

Zinc and copper were determined in urine using polarized Zeeman effect flame atomic absorption spectrophotometry. For the zinc assay, urine was diluted 1/10 with deionized water. Concentrations could be determined by comparison to standards in a salt matrix or in a commercial urine control. The linearity of the assay was 350 micrograms/l, the detection limit was 1.2 micrograms/l and the within-run relative standard deviation (RSD) was 2.08%, 3.06%, 0.71% and 1.29% for specimens with zinc concentrations of 202 micrograms/l, 206 micrograms/l, 1 003 micrograms/l and 1 032 micrograms/l, respectively. The between-run RSD was 2.34% for a mean zinc concentration of 461 micrograms/l. For the copper assay, urine was aspirated directly and concentrations were determined by standard additions. The linearity of the assay was 5 000 micrograms/l, the detection limit was 4.6 micrograms/l and the within-run RSD was 24.49%, 16.10%, 4.00% and 3.19% for specimens with copper concentrations of 9.8 micrograms/l, 11.8 micrograms/l, 50.0 micrograms/l and 50.2 micrograms/l, respectively. The between-run RSD was 8.78% and 4.72% for specimens with copper concentrations of 21.1 micrograms/l and 40.3 micrograms/l, respectively.

The value of serum copper levels in non-Hodgkin's lymphoma

A study of 306 serum copper levels (SCL) determinations in 115 patients with non-Hodgkin's lymphoma indicates a positive correlation between SCL and the state of disease. Patients with advanced disease (Stages II, III and IV) before treatment, those with active disease while under treatment, or in a relapse had a significantly higher SCL than patients in Stage I or those with no evidence of disease (NED). The mean SCL of patients with Stage I was similar to that of patients with NED. The mean values of these two groups did not differ significantly from that of healthy controls. Histological subtypes, according to the Rappaport classification, has no influence on SCL. Grouping into nodular versus diffuse lymphoma, histiocytic versus lymphocytic lymphoma and favorable versus unfavorable histology failed to demonstrate a difference between the groups. Within each subset a wide range of SCL was evident. However, good correlation was observed with the degree of disease activity. SCL may provide a useful parameter for patient monitoring. In this series, however, SCL was not useful for the prediction of an early relapse.

Evidence against a zinc binding peptide in pilocarpine-stimulated canine prostatic secretions

Pilocarpine-stimulated canine prostatic secretions were subjected to gel filtration chromatography over Sephadex G-100 and Bio Gel P-4. Free zinc and the zinc in pilocarpine-stimulated canine prostatic secretions were observed to elute in the same fractions from the Sephadex G-100 column. In addition, Sephadex G-100 chromatography could not resolve free zinc from the small peptide bacitracin. However, a column packed with Bio Gel P-4 could resolve free zinc and bacitracin. When pilocarpine-stimulated canine prostatic secretions were chromatographed over the Bio Gel P-4 column, the major portion of the zinc eluted in the same fractions as did free zinc. No zinc was observed in the fractions where the small peptide bacitracin was found to elute. These results indicate that contrary to a previous report, zinc in pilocarpine-stimulated canine prostatic secretions was not bound to an eight amino acid peptide, but, rather, behaved chromatographically like free zinc.

The laboratory evaluation of microcytic red blood cells

Microcytic red blood cell states are common clinical problems in both adult and pediatric age groups. The recent widespread availability of electronic blood cell counters for performing routine blood counts has increased the detection of microcytic red blood cells. Physicians must workup both symptomatic and asymptomatic patients with microcytic red blood cells before they can initiate proper therapy and/or counseling. The purpose of this review is threefold: (1) to discuss the causes of microcytic red blood cells in terms of disorders of decreased heme production vs. disorders of decreased globin production, (2) to review the clinical laboratory tests useful in differentiating microcytic red blood cell states, and (3) to present a practical approach for the laboratory workup of microcytic red blood cells.

Argyria-tissue deposition of silver as selenide

Generalized argyria was precipitated in a patient by treating gingival erosions with a solution of silver nitrate for several months. High silver concentrations were measured in skin biopsies. treatment with penicillamine did not increase the urinary silver excretion, indicating that silver is deposited in tissues in a chemically stable and apparently inert form. Electron microscopy showed that in the kidney, silver was deposited mainly in the basal membranes as electron-dense particles. These particles were studied by using X-ray emission spectrometry and electron diffraction. the particles consisted of Ag2Se in the low temperature orthorhombic alfaform. The lattice parameters are: a = 0.433 nm, b = 0.693 nm and c = 0.784 nm. This selenide complex seems to be remarkably non-toxic, since the renal function of the patient was unaffected and only negligible reactive changes were observed in kidney biopsies.

Studies on metals in meningiomas by atomic absorption spectrometry

The content of Cr, Mn, Cu, Mg, Ca, Zn, and Fe has been determined by atomic absorption spectrometry in 30 meningiomas and in Pacchionian granulations. The elements Cr, Mn, and Cu show no distinct relation to different tumor types. The broad spectrum of data for Fe is considered to be due to a different blood volume or microbleedings in the meningiomas clinically irrelevant in nature. The Ca-values correspond with the microscopic calcifications. An obvious coincidence exists partly between the high Ca- and Mg-values, in some tumors concentrations of Mg are partly higher than the concentrations of Ca. The latter finding is in concordance with tumors without microscopic calcifications. It is assumed that the inhibitory potency of Mg against mineralization reflects the metabolic antagonism between Ca and Mg. The highest values for Zn are seen in fibromatous meningiomas. This finding possibly corresponds with the function of Zn as co-enzyme in the synthesis of proteins in this copiously reticulin- and collagen-producing type of meningioma.

Effects of oral contraceptives on zinc and copper levels in human plasma and endometrium during the menstrual cycle

Effects of Ovulen-21, Demulen, Enovid-E and Ovral on zinc and copper levels in human plasma and endometrium during the menstrual cycle have been studied. Both plasma and endometrium copper levels were significantly elevated above the control values (P less than 0.001) in women taking oral contraceptives while the zinc levels remained reasonable constant.

Determination of gold in plasma and plasma fractions by atomic absorption spectrometry and by neutron activation analysis

Three techniques of gold analysis, flame and electrothermal atomic absorption spectrometry and neutron activation analysis, have been compared, using plasma and plasma fractions (derived by gel chromatography) from rheumatoid patients receiving aurothiomalate therapy and from plasma samples incubated with aurothiomalate in vitro. The three methods correlated well in the analysis of gold in whole plasma, but only neutron activation analysis was suitable for the assay of all the plasma fractions. The susceptibility of the two atomic absorption methods to interference by sodium chloride was investigated.

Quantitative analysis of trace elements in human blood and plasma by energy dispersive X-ray fluorescence

A photon excitation, secondary target x-ray fluorescence system was used to measure concentrations of Cu, Zn, Br and Rb in whole blood and plasma of healthy adults. The samples preparation method and calculated limits of detection of the technique are reported. Correlation statistics for elemental concentrations have been determined. Verification of the results for copper was performed using atomic absorption spectrophotometry.