The Effect of Cadmium on GFR Is Clarified by Normalization of Excretion Rates to Creatinine Clearance.

Erroneous conclusions may result from normalization of urine cadmium and N-acetyl-β-D-glucosaminidase concentrations ([Cd] and [NAG]) to the urine creatinine concentration ([cr]). In theory, the sources of these errors are nullified by normalization of excretion rates (E and E) to creatinine clearance (C). We hypothesized that this alternate approach would clarify the contribution of Cd-induced tubular injury to nephron loss.

The Source and Pathophysiologic Significance of Excreted Cadmium.

In theory, the identification of the source of excreted cadmium (Cd) might elucidate the pathogenesis of Cd-induced chronic kidney disease (CKD). With that possibility in mind, we studied Thai subjects with low, moderate, and high Cd exposure. We measured urine concentrations of Cd, ([Cd]); N-acetyl-β-d-glucosaminidase, a marker of cellular damage ([NAG]); and β-microglobulin, an indicator of reabsorptive dysfunction ([βMG]).

The inverse association of glomerular function and urinary β2-MG excretion and its implications for cadmium health risk assessment.

Urinary β2-microgroblin (β2-MG) excretion levels above 300 μg/g creatinine are used to indicate defective tubular reabsorption. Arguably, increased urinary β2-MG excretion could also reflect glomerular filtration rate decline. Thus, we investigated an association between urinary β2-MG and estimated glomerular filtration rate (eGFR).

Bone Fracture Risk and Renal Dysfunction in a Highly Cadmium Exposed Thai Population.

Background: Paddy fields in the Mae Sot, Tak Province of Thailand are polluted with unsafe levels of cadmium (Cd). Elderly populations have a high Cd body burden, putting them at elevated risk of renal dysfunction and bone fractures. We aimed to compare bone fracture risk between glomerular dysfunction, proximal tubular dysfunction, and calcium (Ca) handling abnormalities.

Urinary Cadmium Threshold to Prevent Kidney Disease Development.

The frequently observed association between kidney toxicity and long-term cadmium (Cd) exposure has long been dismissed and deemed not to be of clinical relevance. However, Cd exposure has now been associated with increased risk of developing chronic kidney disease (CKD). We investigated the link that may exist between kidney Cd toxicity markers and clinical kidney function measure such as estimated glomerular filtration rates (eGFR).

Cadmium exposure and age-associated DNA methylation changes in non-smoking women from northern Thailand.

DNA methylation changes with age, and may serve as a biomarker of aging. Cadmium (Cd) modifies cellular processes that promote aging and disrupts methylation globally. Whether Cd modifies aging processes by influencing establishment of age-associated methylation marks is currently unknown.

Gender-Specific Impact of Cadmium Exposure on Bone Metabolism in Older People Living in a Cadmium-Polluted Area in Thailand.

To elucidate the influence of cadmium exposure on bone metabolism, associations between urinary/blood cadmium and bone resorption/formation markers were investigated in older cadmium exposed men and women. Increased urinary cross-linked N-telopeptide of type I collagen (NTx), a bone resorption marker, was found to be associated with increased levels of parathyroid hormone, fractional excretion of calcium, and urinary/blood cadmium after adjusting for confounding factors in men. In women, urinary NTx was significantly associated with only urinary cadmium and a strong relationship with increased fractional excretion of calcium.

DNA methylation is differentially associated with environmental cadmium exposure based on sex and smoking status.

The adverse health effects of cadmium (Cd) are well known in human populations; however, much of what is known about biological mechanisms of Cd comes from in vitro and animal studies. The adverse health outcomes due to high levels of Cd exposure in the population of Mae Sot, Thailand have been extensively characterized. Here, for the first time, this population is being studied in an epigenetic context.

Risk assessment for Thai population: benchmark dose of urinary and blood cadmium levels for renal effects by hybrid approach of inhabitants living in polluted and non-polluted areas in Thailand.

Background: The aim of the present study was to estimate the benchmark doses (BMD) for renal effects for health risk assessment of residents living in Cd-polluted and non-polluted areas in a Thai population.

Methods: The study participants consisted of inhabitants aged 40 years or older who lived in a non-polluted area (40 men and 41 women) and in the environmentally polluted Mae Sot District (230 men and 370 women) located in northwestern Thailand. We measured urinary and blood cadmium (Cd) as markers of long-term exposure and urinary β2-microglobulin (β2-MG) and N-acetyl-β-D-glucosaminidase (NAG) as renal tubular effect markers.

A biomarker found in cadmium exposed residents of Thailand by metabolome analysis.

First, the urinary metabolic profiling by gas chromatography-mass spectrometry (GC-MS), was performed to compare ten cadmium (Cd) toxicosis cases from a Cd-polluted area in Mae Sot (Thailand) with gender-matched healthy controls. Orthogonal partial list square-discrimination analysis was used to identify new biomarker candidates in highly Cd exposed toxicosis cases with remarkable renal tubular dysfunction. The results of the first step of this study showed that urinary citrate was a negative marker and myo-inositol was a positive marker for Cd toxicosis in Thailand.

Use of the kidney injury molecule-1 as a biomarker for early detection of renal tubular dysfunction in a population chronically exposed to cadmium in the environment.

Cadmium (Cd) has been found as an environmental pollutant in Mae Sot district, Tak province, Thailand. Prolong exposure to high levels of Cd of the resident increases high risk of Cd toxicity especially to kidney which is the primary target of Cd. In order to investigate the early effect of Cd induced renal dysfunction, a kidney injury molecule-1 (KIM-1), a novel biomarker of renal tubular dysfunction, was measured using an enzyme linked immunosorbent assay (ELISA).

Modeling cadmium exposures in low- and high-exposure areas in Thailand.

Background: Previous U.S. population modeling studies have reported that urinary cadmium (Cd) excretion patterns differ with age, sex, and dietary exposure; associations between Cd exposures and health outcomes also have differed by age and sex.

Cadmium-exposed population in Mae Sot District, Tak Province: 4 bone mineral density in persons with high cadmium exposure.

Objective: To measure bone mineral density in cadmium-exposed persons aged 40 years and older that lived in the 12 contaminated villages in northwestern Thailand.

Material And Method: Five hundred seventy three persons with urinary cadmium levels > or = 5 microg/g creatinine during the 2004-2006 surveys were screened in 2007 for urinary excretion of cadmium, bone formation and resorption markers, and renalfunction markers. Calcaneus bone density was measured in each person by a dual-energy X-ray absorptiometry bone scanner.

Cadmium induced renal dysfunction among residents of rice farming area downstream from a zinc-mineralized belt in Thailand.

High levels of cadmium (Cd) in paddy soil and rice, and a concurrent increase in urinary Cd of inhabitants in the Mae Sot District, Tak Province, Thailand first emerged in 2003. Risk factors such as occupation, sources of staple food and drinking water as well as biomarkers of adverse renal effects of the increased body burden of Cd were investigated in 795 residents, 30 years or older, whose urinary Cd levels were between 0.02 and 106mug/g creatinine.

Bone resorption acceleration and calcium reabsorption impairment in a Thai population with high cadmium exposure.

Some residents of the Mae Sot district in Thailand have suffered long-term exposure to elevated dietary levels of cadmium. To test the hypothesis that chronic dietary cadmium exposure can cause imbalance in calcium dynamics and accelerate bone resorption, a group of these residents (156 men and 256 women aged >/= 50) were selected on the basis of previous records of elevated urinary cadmium and tested for urinary and blood cadmium, bone formation and resorption markers, and the renal tubular dysfunction markers. Both genders had high levels of blood and urinary cadmium and high urinary levels of the markers for renal dysfunction and bone resorption in a dose-response relationship to urinary cadmium.

Discrimination of bullet types using analysis of lead isotopes deposited in gunshot entry wounds.

In order to discriminate bullet types used in firearms, of which the victims died, the authors investigated lead isotope ratios in gunshot entry wounds from nine lead (unjacketed) bullets, 15 semi-jacketed bullets, and 14 full-jacketed bullets by inductively coupled plasma-mass spectrometry. It was found that the lead isotope ratio of 207/206 in gunshot entry wounds was the highest with lead bullets, and it decreased in order from full-jacketed to semi-jacketed bullets. Lead isotope ratios of 208/206 or 208/207 to 207/206 at the gunshot entry wound were able to discriminate semi-jacketed bullets from lead and full-jacketed ones, but it was difficult to discriminate between lead and full-jacketed bullets.

Reduction of trihalomethane formation and detoxification of microcystins in tap water by ozonation.

The efficiency of ozonation in comparison to chlorination for removal of microcystins and production of trihalomethanes (THMs) in water was investigated. One hundred and ninety water samples of ozone and chlorine treated water were collected at a water treatment plant between August 2004 and March 2005. The level of THMs, total organic carbon and residual chlorine were determined.

Differences in the element contents between gunshot entry wounds with full-jacketed bullet and lead bullet.

To elucidate characteristics of gunshot residues in gunshot entry wounds with full-jacketed and lead bullets, element contents in entry gunshot wounds and control skins were analyzed by inductively coupled plasma-atomic emission spectrometry (ICP-AES). It was found that a high content of Fe and Zn was deposited in the gunshot entry wounds with full-jacketed bullet, whereas a high content of Pb was deposited in the gunshot entry wounds with lead (unjacked) bullet. It should be noted that the content of Pb was significantly higher in the gunshot entry wounds with lead bullet than in those with full-jacketed bullet.

Monitoring of cadmium toxicity in a Thai population with high-level environmental exposure.

This study evaluated the utility of single and combined measurements of cadmium toxicity markers for surveillance purposes, using a sample of 224 individuals, 30-87 years of age, who were residents of cadmium polluted area in Mae Sot District, Tak Province, Thailand. Urinary cadmium levels excreted by them ranged between 1 and 58 microg/g creatinine with geometric mean of 8.2 microg/g creatinine which was 16-fold greater than the average for the general Thai population of 0.

Reversed-phase liquid chromatographic-mass spectrometric determination of microcystin-LR in cyanobacteria blooms under alkaline conditions.

Reversed-phase HPLC coupled to the atmospheric pressure ionization-electrospray ionization (API-ESI) MS was used for microcystin-LR detection and quantitation in samples of dried Microcystis aeruginosa cells. An alkaline linear gradient (20 mmol/l ammonium hydroxide-acetonitrile, pH 9.7) was used for elution of the toxic peptides.

Serum aluminium in alumina exposed workers.

This study was performed after skepticism occurred in 1994 when alumina, or aluminium oxide, was thought to be the cause of sickness and death for certain workers at the Northern Industrial Park, Lumphun province, Thailand. Zeeman-graphite furnace atomic absorption spectrometric method has been developed to quantify the aluminium (Al) levels in the serum of 399 workers and 500 blood donors. The results showed that Al levels in the directly (n = 62) exposed workers was significantly different from the indirectly exposed (n = 130) and non-exposed (n = 207) workers and donors.