Stereospecific high-performance liquid chromatographic validation of homoeriodictyol in serum and Yerba Santa (Eriodictyon glutinosum)

A stereospecific method of analysis of racemic homoeriodictyol (eriodictyol 3′-methyl ether) in biological fluids is necessary to study pharmacokinetics and disposition in fruits and herbs. A simple high-performance liquid chromatographic method was developed for the determination of homoeriodictyol enantiomers. Separation was achieved in a Chiralcel^® OJ-RH column with UV-detection at 288 nm. The standard curves in serum were linear ranging from 0.5 to 100.0 μg/ml for each enantiomer. The mean extraction efficiency was >88.0%. Precision of the assay was <15% (CV), and was within 12% at the limit of quantitation (0.5 μg/ml). Bias of the assay was <15%, and was within 6% at the limit of quantitation. The assay was applied successfully to stereospecific disposition of homoeriodictyol enantiomers in rats and to the quantification of homoeriodictyol enantiomers in Yerba Santa (Eriodictyon glutinosum).     

Human percutaneous absorption of a direct hair dye comparing in vitro and in vivo results: Implications for safety assessment and animal testing

Although in vitro skin absorption studies often detect small residues of applied test material in the epidermis/dermis, it is uncertain whether the residue is within the living skin. We studied the dermal absorption of a hair dye hydroxyanthraquinone–aminopropyl methyl morpholinium methosulphate (HAM) in human skin in vivo and in vitro. In vivo, skin (back and scalp) received 0.5% HAM in a commercial formulation at 20 μg/cm² After 0.5 or 48 h, skin was tape stripped, followed by cyanoacrylate biopsies (CAB). Sebum from scalp sites was collected for 48 h. In vitro, skin was treated with 20 mg/cm² dye for 0.5 h, penetration determined after 24 h. In vivo, at 0.5 h, total recovery (back) was 0.67 μg/cm² (tape strips + CAB). Fluorescence microscopy showed HAM in the hair follicle openings (HFO). At 0.5 h, scalp tape strips contained 1.80 μg/cm², HFO 0.82 μg/cm². At 48 h, HFO contained 0.21 μg/cm², sebum 0.80 μg/cm². In vivo, skin residues were in the non-living skin and eliminated via desquamation and sebum secretion. In vitro, the SC contained 1.50 μg/cm², epidermis/dermis 0.86 μg/cm², receptor fluid < 0.04 μg/cm², a total of 0.90 μg/cm² was considered to be bioavailable. In vitro epidermis/dermis residues were nearly identical to those located in non-living skin in vivo. In conclusion, in vitro percutaneous penetration studies may produce seemingly bioavailable material , which raises the need for a Threshold of Skin Absorption (TSA) addressing a negligible dermal absorption in order to avoid unnecessary in vivo toxicity studies on substances that produce no significant human systemic exposure.     

Separation and determination of four active components in medicinal preparations by flow injection-capillary electrophoresis

A simple, rapid and accurate method for the separation and determination of paracetamol (Par), pseudoephedrine hydrochloride (Pse), dextromethorphan hydrobromide (Dex) and chlorphenamine hydrogen maleate (Chl) was developed by combination of flow injection and capillary zone electrophoresis for the first time. The analysis was carried out using an unmodified fused-silica capillary (75 mm × 75 μm i.d. × 375 μm o.d., effective separation length of 45 mm) and direct ultraviolet detection at 214 nm, 1.0 kV applied voltage. The optimized running buffer composed of 75 mM sodium borate–15% (v/v) acetonitrile (ACN) (pH^* 9.30) was applied for the separation of the four analytes. The separation was achieved in 4.5 min. The sample throughput rate could reach up to 19 h⁻¹. The repeatability (defined as relative standard deviation) was 0.6%, 1.0%, 2.1%, 1.9% with peak height evaluation and 0.7%, 1.8%, 0.7%, 1.1% with peak area evaluation for Par, Pse, Dex and Chl, respectively. The limits of detection (S/N = 3) were 0.22 μg/ml, 0.29 μg/ml, 0.42 μg/ml and 0.70 μg/ml for Par, Pse, Dex and Chl, respectively. The method was successfully applied to determine the four compounds in three cold medicines with recoveries in the range of 97.18–105.15%.     

HPLC quantification of two isomeric triterpenic acids isolated from Mitracarpus scaber and antimicrobial activity on Dermatophilus congolensis

Oleanolic (OA) and ursolic acids (UA) were isolated for the first time from the alcoholic extract of Mitracarpus scaber possessing antimicrobial effects on Dermatophilus congolensis. These two triterpenic acids were also active (MIC 15 μg/ml) on this causative agent of dermatophilosis in African animals.

To quantify OA and UA in M. scaber, a new, simple and rapid high-performance liquid chromatography (HPLC) method compatible with MS detection was developed and validated. The mobile phase acetonitrile:H₂O (85:15, v/v) was pumped through a C18 octadecylsilyl silica column at a flow rate of 0.6 ml/min and the eluate was monitored at 215 nm. The calibration curves constructed between 0.5 and 10 μg/ml showed linear relationships with good R² values. The developed method was precise and reproducible with relative standard deviations (RSD) for these two active constituents between 0.22–2.06% (intraday) and 1.61–3.72% (interday) for concentrations from 0.5 to 6 μg/ml. Limits of detection and quantification were, respectively, 0.2 and 0.5 μg/ml.     

Pharmacokinetics of thrombin-like enzyme from venom of Agkistrodon halys ussuriensis Emelianov determined by ELISA in the rat.

A thrombin-like enzyme (TLE) was separated and purified from the venom of a northeast Chinese snake Agkistrodon halys ussuriensis Emelianov. Experiments were performed in rats to determine the pharmacokinetic parameters following an intravenous (i.v.) or a subcutaneous (s.c.) injection of the thrombin-like enzyme. The plasma levels of TLE were estimated by enzyme-linked immunosorbent assay. The method exhibited high reproducibility and accuracy in correlating optical densities with TLE concentrations (0.2–30 ng ml⁻¹, r=0.99). The plasma concentration-time course after i.v. administration of 50 μg kg⁻¹ TLE was well fitted by a two-compartment open model. The half-life of the -phase was 18.0±3.2 min, and that of the β-phase 3.9±0.7 h. The apparent volume of distribution was 1.8±0.5 l kg⁻¹, and clearance was 5.4±0.5 ml min⁻¹ kg⁻¹. When the TLE was injected s.c. at a dose of 0.75 mg kg⁻¹, the changes in plasma concentration were best described by a two-compartment model with a first-order absorption. The maximal plasma level of 51±2.7 ng ml⁻¹ was reached at 5.2±0.5 h. The absorption rate constant was 0.3±0.03 h⁻¹. The area under the plasma concentration-time curve (AUC) was 2.8±0.8 μg h⁻¹ ml⁻¹.     

The renal effects of Bothrops jararacussu venom and the role of PLA2 and PAF blockers

The most common complication in the lethal cases of ophidian bites in Brazil is acute renal failure, but its pathogenesis is obscure. The effects of Bothrops jararacussu venom (3, 10 and 30 μg/ml) were examined using the isolated perfused kidney from Wistar rats. Dexamethasone, and WEB 2086, a triazolobenzodiazepine substance, which is a platelet activating factor receptor antagonist, were tested for a possible blockade of the renal effects in the presence of 10 μg/ml of venom. The most intense effects of the venom were noticed at 120 min after using 30 μg/ml. We observed a decrease in the perfusion pressure and in the renal vascular resistance. However, the glomerular filtration rate (GFR) and the urinary flow (UF) increased significantly. The percent of sodium (%Na_tot⁺) and potassium (%K_tot⁺) tubular transport were also decreased. Dexamethasone was unable to block the effects of B. jararacussu in the kidney, while WEB 2086 blocked its effect in glomerular filtration rate, urinary flow and in the percentage of total tubular potassium reabsorption. We suggest that this venom promotes diuresis independently of perfusion pressure drop. The alterations in GFR, UF and %K_tot⁺ are probably mediated by platelet activating factor. Dexamethasone did not block the renal effects maybe because of the concentration used in this work or maybe the renal effects are promoted by the myotoxin, which does not have PLA₂ activity.     

Determination of catecholamines by flow-injection analysis and high-performance liquid chromatography with chemiluminescence detection

A chemiluminescence (CL) detection of catecholamines [norepinephrine (NE), epinephrine (E), dopamine (DA) and l-dopa (LD)] is described for the flow-injection (FI) and high-performance liquid chromatographic (HPLC) determination of these compounds. The detection method is based on the inhibition effect of catecholamines (CAs) on the CL reaction of luminol with iodine in the alkaline medium. The proposed FI method allows the determination of CAs in pharmaceutical preparations for the purpose of drug quality control. The calibration curves show good linearity in the concentration range of: 1.1–20.0 μg l⁻¹ (NE), 0.5–5.0 μg l⁻¹ (E), 0.6–9.0 μg l⁻¹ (DA) and 0.6–10.0 μg l⁻¹ (LD). The limits of detection (defined as a signal-to-noise ratio of 3) are: 0.34 μg l⁻¹ (NE), 0.15 μg l⁻¹ (E) and 0.18 μg l⁻¹ (DA, LD). The HPLC procedure was successfully applied for the determination of catecholamines (NE, E, DA) in human urine after solid-phase extraction (SPE). In a simple run time CAs can be determined in 20 min. The chromatographic linear ranges are: 5.0–72.0 μg l⁻¹ (NE), 5.0–48.0 μg l⁻¹ (E) and 5.0–96.0 μg l⁻¹ (DA). The limits of detection for three urinary CAs are: 0.71 μg l⁻¹ (NE), 0.26 μg l⁻¹ (E) and 0.73 μg l⁻¹ (DA).     

In vitro distribution of ketoprofen enantiomers in articular tissues of osteoarthritic patients

The distribution of ketoprofen enantiomers in joint tissues was studied as a function of their relative tissular affinities using the multi-chamber distribution dialysis system described by Bickel et al. Selected off-cuts of synovial membrane, joint capsule, cartilage and ligament were obtained from ten patients suffering from osteoarthritis of the knee (n=3) or hip (n=7). Sörensen solution (4 ml) spiked with racemic ketoprofen (2 μg ml⁻¹) was dialysed against 1 ml of the four solutions of tissue homogenates (0.4 g ml⁻¹). Ketoprofen enantiomers were quantified in buffer and tissue solutions by high-performance liquid chromatography. The distribution of ketoprofen enantiomers in the Bickel's multi-compartment model indicated that there was a non-stereoselective affinity of ketoprofen enantiomers for their potential target tissues. Despite the interindividual variability in articular tissues, the concentrations (±S.D.) of R- and S-ketoprofen were significantly higher in synovial membrane (8.69 (4.76) μg g⁻¹ for S, 9.14 (5.57) μg g⁻¹ for R), joint capsule (5.71 (2.49) μg g⁻¹ for S, 5.49 (2.62) μg g⁻¹ for R) and ligament (6.28 (3.61) μg g⁻¹ for S, 6.40 (3.64) μg g⁻¹ for R) than in articular cartilage (3.67 (1.75) μg g⁻¹ for S, 3.70 (1.67) μg g⁻¹ for R). There were no significant differences in the distribution of R- and S-ketoprofen between the solutions of joint capsule, synovium and ligament tissues. These data may be related to differences in ketoprofen affinity for the different constituents of joints. This in vitro distribution profile is similar to that reported in vivo for other non-steroidal anti-inflammatory drugs.     

Protection of extract from leaves of Ardisia compressa against benomyl-induced cytotoxicity and genotoxicity in cultured rat hepatocytes

The potential of the Ardisia compressa extract (EA) was examined regarding its capacity to reduce the cytotoxic effect of benomyl on rat hepatocytes. The protective effect was evaluated by Janus Green dye exclusion method. An approximate 50% cytotoxic effect of benomyl on hepatocytes was observed at 35 μg/ml after 2 hr of incubation. (−)Epigallocatechin 3-gallato (EGCG) and EA decreased the viability of hepatocytes at concentrations above 3 μg/ml and 2.52 μg, equivalent to (+)catechin/ml, respectively. A protective effect against benomyl was observed when hepatocytes were previously exposed to EGCG (3 μg/ml) or EA (2.52 μg, equivalent to (+)catechin/ml) followed by incubation with benomyl (35 μg/ml) alone. When EGCG or EA were in contact with cells, either simultaneously or after pretreatment with benomyl, did not protect hepatocytes. EGCG (1.3×10⁻² μg/ml) or EA (9.8×10⁻² μg, equivalent to (+)catechin/ml) inhibited 57% and 34%, respectively, the unscheduled DNA synthesis (UDS) induced by benomyl at a concentration of 23×10⁻² μ , when both were incubated with hepatocytes prior to benomyl. The simultaneous incubation of benomyl with EGCG or EA did not protect the cell against the genotoxic effect of benomyl. These results indicate that the dried leaves extract of Ardisia compressa protect rat hepatocytes from benomyl-induced cytotoxicity and genotoxicity.     

Inhibition of P-type ATPases by [(dihydroindenyl)oxy]acetic acid (DIOA), a K+ -Cl- cotransporter inhibitor

[(Dihydroindenyl)oxy]acetic acid (DIOA) has been used as a potent inhibitor of K⁺–Cl⁻ cotransporter (IC₅₀ = 10 μM). Here we found that DIOA inhibited activities of P-type ATPases such as dog kidney Na⁺,K⁺-ATPase (IC₅₀ = 53 μM), hog gastric H⁺,K⁺-ATPase (IC₅₀ = 97 μM) and rabbit muscle Ca²⁺-ATPase (IC₅₀ = 127 μM). In the membrane preparation of the LLC-PK1 cells stably expressing rabbit gastric H⁺,K⁺-ATPase, DIOA inhibited activities of the endogenous Na⁺,K⁺-ATPase (IC₅₀ = 95 μM) and the exogenous H⁺,K⁺-ATPase (IC₅₀ = 75 μM). 5-Nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB), a Cl⁻ channel blocker, had no effects on the DIOA-elicited inhibition of the P-type ATPases. These findings suggest that lower concentration of DIOA (< 20–30 μM) should be used for evaluation of the activity of K⁺–Cl⁻ cotransporter without affecting the activities of coexisting Na⁺,K⁺-ATPase and/or H⁺,K⁺-ATPase in cells.     

Delta(9)-Tetrahydrocannabinol-induced desensitization of cannabinoid-mediated inhibition of synaptic transmission between hippocampal neurons in culture

Prolonged exposure to cannabinoids results in desensitization of cannabinoid receptors. Here, we compared the desensitization produced by the partial agonist, Δ⁹-tetrahydrocannabinol (THC) to that produced by the full agonist Win55,212-2 on cannabinoid-mediated inhibition of glutamatergic synaptic transmission. Synaptic activity between rat hippocampal neurons was determined from network-driven increases in the intracellular Ca²⁺ concentration ([Ca²⁺]_i spikes). To assess the effects of prolonged treatment, cultures were incubated with cannabinoids, washed in 0.5% fatty-acid-free bovine serum albumin to ensure the removal of the lipophilic drug and then tested for inhibition of [Ca²⁺]_i spiking by Win55,212-2. In control experiments, 0.1 μM Win55,212-2 inhibited [Ca²⁺]_i spiking by 93 ± 5%. Win55,212-2 produced significantly less inhibition of [Ca²⁺]_i spiking following 18–24 h treatment with 1 μM THC (48 ± 5%) or treatment with 1 μM Win55,212-2 (29 ± 6%). Thus, THC produced significantly less functional desensitization than Win55,212-2. The desensitization produced by THC was maximal at 0.3 μM, remained stable between 1 and 7 days of preincubation and shifted the EC₅₀ of acute inhibition by Win55,212-2 from 27 to 251 nM. Differences in the long-term effects of cannabinoid receptor agonists on synaptic transmission may prove important for evaluating their therapeutic and abuse potential.     

Interaction between accumulation of cadmium selenium in the tissues of turbot Scophthalmus maximus

The interaction between accumulation of waterborne cadmium and selenite in juvenile turbot, Scophthalmus maximus, was investigated in the laboratory. Intestine, kidney and liver of turbot exposed to 150 μg Cd 1⁻¹ accumulated cadmium linearly with time over 5 wk at rates of 0.50, 0.014 and 0.11 μg Cd g⁻¹ dry wt. d⁻¹, respectively. Gills, skin and muscle reached steady-state cadmium levels of ca. 15, 0.8 and 0.25 μg Cd g⁻¹ after 1–3 wk of exposure. Plasma and erythrocytes reached steady-state concentrations of ca. 0.1 and 1–2 μg Cd ml ⁻¹ after 1–2 wk of exposure. Exposure to 105 μg Se-SeO₃²⁻1⁻¹ did not consistently alter selenium concentrations in gills, skin, liver, muscle and erythrocytes of juvenile turbot. Kidneys accumulated selenium linearly (0.029 μg Se g⁻¹ dry wt. d⁻¹) with time over 5 wk, while intestine reached a steady-state level after 2 wk. Selenium concentrations in the plasma were maintained close to the ambient level throughout the exposure time. Concurrent exposure to selenite augmented cadmium accumulation rates in gills, kidney and liver and reduced cadmium accumulation in intestine and erythrocytes; cadmium accumulation in spleen, skin, muscle and plasma was not affected. Concurrent exposure to cadmium depleted erythrocytes and partly skin of selenium and reduced accumulation of selenium in kidney and plasma, whereas selenium accumulation patterns in gills, intestine, liver, muscle and spleen were not affected by exposure to cadmium.     

Effect of glutamate and extracellular calcium on uptake of inorganic lead (Pb2+) in immortalized mouse hypothalamic GT1-7 neuronal cells

We have previously shown that although glutamate alone has no effects on viability of mouse hypothalamic GT1–7 cells, it clearly enhances Pb²⁺-induced cytotoxicity. It is likely that Pb²⁺ must enter cells to exert most of its toxic effects. Pb²⁺ is known to substitute for Ca²⁺ in many cellular processes. Therefore, we studied the uptake mechanisms of Pb²⁺ into GT1–7 neuronal cells with a special focus on the role of extracellular calcium (Ca²⁺), voltage-sensitive calcium channels (VSCCs) and glutamate. Basal uptake of Pb²⁺ (1 μM or 10 μM), i.e. without any external stimulus, clearly increased in nominally Ca²⁺-free buffer and was partially abolished by 13 mM Ca²⁺ when compared to uptake in the presence of a physiological concentration of extracellular Ca²⁺ (1.3 mM). Depolarization by 25 mM K⁺, or antagonists of VSCCs, verapamil (10 μM) or flunarizine (10 μM) had no clear effect on basal Pb²⁺ uptake. Glutamate (1 mM) increased Pb²⁺ uptake, but only when cells were treated with 1 μM Pb²⁺ in the presence of 1.3 mM Ca²⁺. Our data suggest that Pb²⁺ competes for the same cellular uptake pathways with Ca²⁺, although not via VSCCs. In addition, enhancement of Pb²⁺-induced neurotoxicity by glutamate may be due to increased neuronal uptake of Pb²⁺.     

Simultaneous determination of nikethamide and lidocaine in human blood and cerebrospinal fluid by high performance liquid chromatography

Nikethamide and lidocaine are often requested to be quantified simultaneously in forensic toxicological analysis. A simple reversed-phase high performance liquid chromatography (RP-HPLC) method has been developed for their simultaneous determination in human blood and cerebrospinal fluid. The method involves simple protein precipitation sample treatment followed by quantification of analytes using HPLC at 263 nm. Analytes were separated on a 5 μm Zorbax Dikema C₁₈ column (150 mm × 4.60 mm, i.d.) with a mobile phase of 22:78 (v/v) mixture of methanol and a diethylamine–acetic acid buffer, pH 4.0. The mean recoveries were between 69.8 and 94.4% for nikethamide and between 78.9 and 97.2% for lidocaine. Limits of detection (LODs) for nikethamide and lidocaine were 0.008 and 0.16 μg/ml in plasma and 0.007 and 0.14 μg/ml in cerebrospinal fluid, respectively. The mean intra-assay and inter-assay coefficients of variation (CVs) for both analytes were less than 9.2 and 10.8%, respectively. The developed method was applied to blood sample analyses in eight forensic cases, where blood concentrations of lidocaine ranged from 0.68 to 34.4 μg/ml and nikethamide ranged from 1.25 to 106.8 μg/ml. In six cases cerebrospinal fluid analysis was requested. The values ranged from 20.3 to 185.6 μg/ml of lidocaine and 8.0 to 72.4 μg/ml of nikethamide. The method is simple and sensitive enough to be used in toxicological analysis for simultaneous determination of nikethamide and lidocaine in blood and cerebrospinal fluid.     

Tetrabromobisphenol A (TBBPA), induces cell death in TM4 Sertoli cells by modulating Ca transport proteins and causing dysregulation of Ca homeostasis

Tetrabromobisphenol A (TBBPA) is a commonly used brominated flame retardant (BFR) utilized to reduce the flammability of a variety of products. Studies have indicated that a number of BFRs are becoming widely distributed within the environment and are bio-accumulating within organisms. There has been much speculation that a variety of phenolic pollutants (including compounds chemically related to TBBPA, such as bisphenol A) may cause endocrine disruption and Ca²⁺ dysregulation in cells involved in spermatogenesis. In this study we therefore investigate the effects of TBBPA on mouse TM4 Sertoli cells (essential for sperm development). Results show that TBBPA increases Ca²⁺ within these cells in the 5–60 μM concentration range (EC₅₀, 21 μM). TBBPA also causes cell death (LC₅₀, 18 μM) partly via apoptosis, involving Ca²⁺-dependent mitochondrial depolarisation. Studies on intracellular Ca²⁺ transporters shows that TBBPA can inhibit sarcoplasmic/endoplasmic reticulum Ca²⁺-ATPases (SERCA) at low concentrations (IC₅₀, 0.4 to 1.2 μM) and also activate the Ryanodine receptor Ca²⁺ channel within the 0.4–4 μM concentration range. Therefore these studies suggest that the cytotoxic effects of TBBPA on cells is partly due to dysregulation of Ca²⁺ signalling, by directly affecting Ca²⁺ transport proteins.     

Inhibitory effect of Uncaria sinensis on human aortic smooth muscle cell migration is based on matrix metalloproteinase-9 inhibitory activity

Medicinal extracts of Cho-Deung-san and Uncaria sinensis Havil. (UR) have previously been shown to have inhibitory effects on migration of vascular smooth muscle cells (VSMC) and matrix metalloproteinase (MMP)-2/9 production, which play key roles in the development of atherosclerosis. In this study, we have more extensively investigated the inhibitory effect of UR on MMP-9 activity and TNF- induced human aortic smooth muscle cells (HASMC) migration. The result from gelatin zymography showed that UR inhibited MMP-9 activity in a dose-dependent manner (IC₅₀ = 55 μg/ml). In addition, UR strongly inhibited the migration of HASMC induced by TNF- treatment (IC₅₀ = 125 μg/ml), although it has very low cytotoxic effect on HASMC (IC₅₀ > 500 μg/ml). These results suggest that UR is a potential anti-atherosclerotic agent through inhibition of MMP-9 activity and VSMC migration.     

Microcalorimetric investigation of the toxic action of ammonium ferric(III) sulfate on the metabolic activity of pure microbes

A series of calorimetric experiments were performed to investigate toxic action of ammonium ferric sulfate (AFS) on Bacillus subtilis, Pseudomonas putida and Candida humicola. The power–time curves of micro-organism metabolism were obtained, and the action of them by addition of AFS was studied. C. humicola, B. subtilis and P. putida were inhibited completely when the concentrations were up to 320.0, 160.0 and 160.0 μg mL⁻¹, respectively. The relationships between growth rate constant (k) and doses of AFS were approximately linear for three microbes, P. putida for 10.0–160.0 μg mL⁻¹ (R = −0.9746), B. subtilis for 0–160.0 μg mL⁻¹ (R = −0.9868) and C. humicola for 10.0–320.0 μg mL⁻¹ (R = −0.9955). The total heat dissipated per milliliter (Q_T) for three microbes remained balance approximately during the lower doses, P. putida and B. subtilis less than the dose of 20.0 μg mL⁻¹, 0.56 ± 0.01 and 0.26 ± 0.01 J mL⁻¹, respectively, C. humicola less than the dose of 40.0 μg mL⁻¹, 0.58 ± 0.03 J mL⁻¹. The biomass and OD₆₀₀ of three micro-organisms growth in the absence of AFS also were obtained. The power–time curve of C. humicola growth coincided with its turbidity curve. It elucidates that microcalorimetric method agreed with the routine microbiology method.     

Characterisation of exposure to total and hexavalent chromium of welders using biological monitoring

Inhalation exposure to total and hexavalent chromium (TCr and HCr) was assessed by personal air sampling and biological monitoring in 53 welders and 20 references. Median inhalation exposure levels of TCr were 1.3, 6.0, and 5.4 μg/m³ for welders of mild steel (MS, <5% alloys), high alloy steel (HAS, >5% alloys), and stainless steel (SS, >26% alloys), respectively. The median exposures to HCr compounds were 0.23, 0.20, and 0.08 μg/m³, respectively. Median concentrations of TCr in urine, blood plasma and erythrocytes were elevated in all welders, compared with the corresponding median concentrations in the reference group (p < 0.005). The TCr levels observed in plasma were two-fold higher in welders of SS and HAS than in welders of MS (p < 0.01). Exposure to HCr as indicated by median total content of Cr in erythrocytes was 10 μg/L in welders of SS, MS and HAS. Uptake of TCr during the shift was confirmed for welders of SS by a median increase of urinary TCr from pre- to post-shift of 0.30 μg/g creatinine. For welders of MS and HAS as a group TCr was not increased.     

Alteration of pregnancy related hormones and fetal survival in F-344 rats exposed by inhalation to benzo(a)pyrene

The objective of this study was to evaluate the effect of subacute exposure to inhaled benzo(a)pyrene (BaP) on fetal survival and luteal maintenance using timed-pregnant Fisher 344 rats. Prior to assignment of pregnant rats to treatment and control groups, numbers of implantation sites were determined on gestation day (GD) 8 via midventral laparotomy. Subsequently, animals were assigned randomly to three treatment groups and two control groups. Treatment consisted of subacute exposure of rats via inhalation to BaP 25, 75, and 100 μg/m³, 4 h daily for 10 days (GD-11–20). Control animals were either sham exposed to carbon black (CB) to control for inert BaP carrier or remained unexposed (UNC). Blood samples were collected on days 15 and 17 of gestation via sinus orbital veini-puncture for plasma. Number of pups per litter was determined postpartum and fetal survival rate was expressed as a percentage of the corresponding implantation sites. Radioimmunoassays were used to determine plasma progesterone, estrogen, and prolactin (indirect measurement of decidual luteotropin) concentrations. Fetal survival among BaP-treated rats declined in a dose-dependent manner (25 μg/m³, 78.3% per litter; 75 μg/m³, 38.0% per litter; 100 μg/m³, 33.8% per litter; P<0.05) compared with CB (96.7% per litter) and UNC (98.9% per litter). Plasma progesterone, estrogen, and prolactin concentrations also declined as a result of subacute exposure of rats to BaP compared to controls. These data suggest that inhaled BaP compromised fetal survival and consequently luteotropic activity in the exposed animals.     

Evaluation of micronucleus induction of sand dust storm fine particles (PM(2.5)) in human blood lymphocytes

Sand dust storms are common phenomena in the arid and semi-arid regions. Previous studies have demonstrated that the airborne air fine particulate matter (PM_2.5, particulates with an aerodynamic diameter ≤2.5 μm) and its extracts can induce human genetic damage of lymphocytes such as micronucleus formation, chromosomal aberration and so on. However, little is known about the health risks associated with sand dust storm PM_2.5 and its extracts. The aim of the present study is to investigate the micronucleus induction of sand dust storm PM_2.5 (include its organic and inorganic extract) from two different towns on human lymphocytes. The samples of normal PM_2.5 and sand dust storm PM_2.5 were collected in Wuwei (Gansu Province) and Baotou (Inner Mongolia), China. The cytochalasin-B cytokinesis-block test was employed and the cells were treated with 0, 33, 100, 300 μg ml⁻¹ sand dust storm PM_2.5 or normal ambient air PM_2.5 suspension (physiological saline as solvent control), or inorganic extract (0, 75, 150, 300 μg ml⁻¹, physiological saline as solvent control) or organic extract (0, 20, 40, 80 μg ml⁻¹, DMSO as solvent control) at the beginning of the cell culture. Both sand dust storm and normal PM_2.5 and their extract treatment cultures revealed an increase in the frequency of micronucleus. With the increase of treatment concentrations the frequency of micronucleus increased and the nuclear division index (NDI) values declined in a dose–response manner (P < 0.01). In the same concentrates, the frequency of micronucleus of normal ambient air PM_2.5 and its extract were significant higher than those of sand dust storm PM_2.5 (P < 0.01) except the treatment of Wuwei sample at higher doses, the treatment of inorganic extract of PM_2.5 at the highest dose (300 μg ml⁻¹) and the treatment of organic extract of PM_2.5 at the higher dose (40 and 80 μg ml⁻¹) either in Baotou or in Wuwei (P > 0.05). The toxicity of sand dust storm PM_2.5 and its extract at high dose is very potent. The frequency of micronucleus of normal PM_2.5 (include its organic extract) from Baotou were higher than those of Wuwei especially in low and middle dose (P < 0.05), but the treatment results of sand dust storm PM_2.5 (include its all extract) was not significantly different between the towns (P > 0.05).