Speciation measurements by HPLC-HGAAS of dimethylarsinic acid and arsenobetaine in three candidate lyophilized urine reference materials

Speciation measurements of dimethylarsinic acid (DMA) and arsenobetaine (AsB) in three candidate lyophilized urine reference materials are described. The measurements were based on cation-exchange liquid chromatography coupled to hydride generation atomic absorption spectrometry with on-line digestion of the organic. As species by alkaline persulfate solution aided by ultraviolet radiation. Arsenic concentrations as DMA were significantly different in the three samples. The mean values for the three samples were 4.1 +/- 0.3, 55.3 +/- 1.2 and 134.1 +/- 1.5 micrograms l-1, respectively. No significant differences in AsB concentrations were observed among the three samples. The mean As concentrations as AsB in the three samples were 17.4 +/- 0.4, 17.7 +/- 0.2 and 17.5 +/- 0.3 micrograms l-1, respectively. By off-line digestion of the urine samples, total As concentrations in the three materials were also obtained. The mean values were 23.4 +/- 0.3, 76.6 +/- 1.6 and 151.3 +/- 1.8 micrograms l-1, respectively. These results correlated well with the results obtained by neutron activation analysis in our laboratory (r = 0.999; p < 0.0001).

Inductively coupled plasma mass spectrometric determination of molybdenum in urine from a Danish population

Molybdenum creatinine levels in urine were measured in 128 Danish inhabitants by ICP-MS in order to establish reference intervals of molybdenum in urine for the Danish population as a part of the EURO-TERVIHT project (Trace Element Reference Values in Human Tissues). The Mo concentration was determined using the isotopes 95Mo and 98Mo. The values measured based on 98Mo were about 2% lower than those calculated using 95Mo, a negligible difference in the context of reference values. The limit of detection was 0.2 microgram l-1, the precision was 8.6% and the recovery of added NIST 1643c certified reference material was 94%. The distribution of the data, with and without correction for creatinine concentration, was long-normal. The mean concentration measured was 42.5 micrograms l-1, (3.89 micrograms Mo mmol-1 creatinine) using 95Mo and 41.5 micrograms l-1 (3.81 micrograms Mo mmol-1 creatinine) using 98Mo, with the 95% parametric reference intervals 10.0-124.0 micrograms l-1 (0.89-11.50 micrograms Mo mmol-1 creatinine) and 9.6-122.6 micrograms l-1 (0.84-11.47 micrograms Mo mmol-1 creatinine), respectively. The difference between men and women reached the level of significance only after the values were corrected for the creatinine concentration. There was no influence of age on the Mo concentration. Specific effects of different food and beverage intakes could not be demonstrated, with the exception of a positive correlation between butter consumption and Mo concentration.

Trends in quality assurance of metal determination in clinical chemistry

A summary is given of the main strategies that can be used to obtain high quality results in the determination of metals in clinical chemistry. The trends in quality assurance of metal analyses are discussed.

A DANREF certified reference material for chromate in cement

Two candidate reference materials for chromate in cement were produced in the DANREF network and certified in an interlaboratory study. Fifteen laboratories participated in the interlaboratory study and six different analytical methods were used. The certified values were estimated as the consensus mean of laboratory mean values (outliers excluded). Only results from laboratories using methods relying on chromate speciation were accepted. The certified values (+/- 95% confidence limits) were 0.678 (+/- 0.075) mg CrVI kg-1 dry cement for the low level and 6.04 (+/- 0.28) mg CrVI kg-1 dry cement for the high level. Methods based on total chromium determination gave on average results that were 6.5% higher (both levels). However, the difference between speciation and non-speciation results was significant at the high concentration level only.

Toxic trace element reference levels in blood and urine: influence of gender and lifestyle factors

This study is part of the EURO-TERVIHT project (Trace Element Reference Values in Human Tissues) which aims at establishing reference intervals for trace elements in blood, urine and other human tissues. In this study reference intervals (0.05-0.95 fractiles) were estimated for lead in blood (105-529 nmol/l for men, 80-340 nmol/l for women), manganese in blood (100-271 nmol/l) and arsenic in urine (36-541 nmol/l for men, 21-475 nmol/l for women). Upper reference limits (0.95 fractile) were established for chromium in urine (13 nmol/l), nickel in urine (52 nmol/l) and cobalt in urine (23 nmol/l for men, 31 nmol/l for women). The reference group was a Danish subpopulation (n = 189), age 40-70 years. The influence of gender, age, health status parameters, nutrition and various lifestyle factors was investigated. Urinary arsenic and blood lead levels were found to be higher for men than for women. Arsenic levels also increased with age up to 60 years, and then decreased. Alcohol intake lead to increased arsenic levels in urine as well as blood lead levels. Urinary nickel levels were higher in persons frequently eating porridge and porridge oats.

Identifying denial in stroke patients

The purpose of this study was to test the reliability of an experimental assessment tool for identifying and differentiating between psychodynamic and neurogenic denial in stroke patients. A one-page criterion referenced denial assessment tool was used by interdisciplinary rater teams to evaluate patients with either right or left hemisphere insults. High interrater reliability was obtained. Assessment data indicated that right-CVA patients had higher psychodynamic and neurogenic denial scores than left-CVA patients. Higher psychodynamic denial scores were also observed in the second month post-stroke. The experimental denial assessment tool proved to be a practical way for identifying and differentiating psychodynamic and neurogenic forms of denial. This tool can provide a means for ongoing assessment to support precise nursing diagnoses and promote effective patient-focused care planning throughout the rehabilitation process.

Cryopreservation of channel catfish spermatozoa: Effect of cryoprotectant, straw size, and formulation of extender

Various aspects of the cryopreservation of spermatozoa of channel catfish (Ictalurus punctatus ) were studied in relation to spermatozoa motility. The objectives were to evaluate 1) the efficacy of 5, 10 and 15% of methanol or n,n-dimethyl acetamide (DMA) as cryoprotectants; 2) the acute toxicity of 5, 10 and 15% methanol or DMA; 3) the use of 0.5-ml vs. 0.25-ml straws; 4) the efficacy of 5, 10 and 15% of methanol in Hanks' balanced salt solution (HBSS) or HBSS without glucose, and 5) the use of HBSS with or without 5% methanol. We found that use of 5% methanol as a cryoprotectant resulted in significantly higher post-thaw motility (P = 0.0001) than did 5, 10 or 15% DMA. The use of 5% of either cryoprotectant resulted in significantly higher post-thaw motility (P = 0.0001) than did 10 or 15% of the cryoprotectants. Samples containing 10 or 15% DMA had significantly lower motility (P = 0.0001) after 30 min exposure than did samples containing 5, 10 or 15% methanol. The use of 0.25-ml straws resulted in significantly higher post-thaw motility (P = 0.0001) than that of 0.5-ml straws. No difference was found in post-thaw motility between HBSS with and without glucose as the extenders. Cryopreservation in HBSS without addition of cryoprotectant resulted in post-thaw motility values of about 1%.

Critical evaluation and review of cadmium concentrations in blood for use in occupational health according to the TRACY protocol

Cadmium in blood (B-Cd) may be used to assess recent exposure to cadmium in the working or general environment. In a paper published elsewhere pooled reference values using meta-analysis of B-Cd values in general-population studies were calculated. In the present study tentative references intervals were described which can be used for comparison with data from occupationally exposed groups or individuals. The selection of studies was done according to criteria as published by the international project TRACY. For this purpose, 800 publications covering the period 1983-1992 were reviewed on their suitability for establishing tentative reference intervals. From these 800 publications, four finally met the selection criteria. Most important criteria for selection were the check for contamination during sampling of the blood, the storage and pretreatment procedures, and the existence of internal and external quality control programs. Also, stratifications into sex, smoking habits and occupation were important selection criteria. It turned out that for non-smoking white-collar workers in the age range of 19-65 years, B-Cd values were below 0.8 micrograms/l for most areas. All other groups within this age group, e.g., white collar workers in Japan, blue-collar workers, and smokers tend to have higher B-Cd values in these sequences. Blue-collar workers not clearly exposed to Cd have higher values than white-collar workers, indicating still some minor exposure. It is not clear if this small exposure has an occupational or lifestyle (e.g., diet) origin. Geographical regions also show an influence on B-Cd levels, e.g., values in Japan are higher than elsewhere. This influence may be due to differences in diet. The conclusion will be that reference values for B-Cd in fact are area-dependent.

The disposition of five therapeutically important antimicrobial agents in llamas

The disposition of five therapeutic antimicrobial agents was studied in llamas (Lama glama) following intravenous bolus administration. Six llamas were each given ampicillin, tobramycin, trimethoprim, sulfamethoxazole, enrofloxacin and ceftiofur at a dose of 12 mg/kg, 1 mg/kg, 3 mg/kg, 15 mg/kg, 5 mg/kg, and 2.2 mg/kg of body weight, respectively, with a wash out period of at least 3 days between treatments. Plasma concentrations of these antimicrobial agents over 12 h following i.v. bolus dosing were determined by reverse phase HPLC. Disposition of the five antimicrobial agents was described by a two compartment open model with elimination from the central compartment, and also by non-compartmental methods. From compartmental analysis, the elimination rate constant, half-life, and apparent volume of distribution in the central compartment were determined. Statistical moment theory was used to determine noncompartmental pharmacokinetic parameters of mean residence time, clearance, and volume of distribution at steady state. Based on the disposition parameters determined, and stated assumptions of likely effective minimum inhibitory concentrations (MIC) a dose and dosing interval for each of five antimicrobial agents were suggested as 6 mg/kg every 12 h for ampicillin; 4 mg/kg once a day or 0.75 mg/kg every 8 h for tobramycin; 3.0 mg/kg/15 mg/kg every 12 h for trimethoprim/sulfamethoxazole; 5 mg/kg every 12 h for enrofloxacin; and 2.2 mg/kg every 12 h for ceftiofur sodium for llamas. Steady-state peak and trough plasma concentrations were also predicted for the drugs in this study for llamas.

Sample collection guidelines for trace elements in blood and urine. IUPAC Commission of Toxicology

This paper presents an organized system for element-specific sample collection and handling of human blood (whole blood, serum or plasma, packed cells or erythrocytes) and urine also indicating a proper definition of the subject and sample. Harmonized procedures for collection, preparation, analysis and quality control are suggested. The aim is to assist scientists worldwide to produce comparable data which will be useful on a regional, national and international scale. The guidelines are directed to the elements aluminium, arsenic, cadmium, chromium, cobalt, copper, lead, lithium, manganese, mercury, nickel, selenium and zinc. These include the most important elements measured for their occupational or clinical significance, and serve as examples of principles that will guide development of methods for other elements in the future.

Blood lead in the general population in Poland

Lead concentration in venous blood (Pb-B) was investigated in 1122 inhabitants (including 555 children under 10 years of age) of five Polish towns with no large industrial lead emitters (group I) and in 1246 persons (707 children under 10 years of age) living in the vicinity of zinc and copper mills (group II). The samples were analysed using electrothermal atomic absorption spectrometry (ETAAS) and the performing laboratory participated in the external quality control scheme during the study period (1992-1994). In group I the mean geometric Pb-B concentrations ranged from 23.8 to 48.3 micrograms/l in females, from 42.5 to 76.8 micrograms/l in males and from 29.9 to 62.5 micrograms/l in children. In group II, the mean geometric Pb-B concentrations were significantly higher and ranged from 49.4 to 105 micrograms/l in females, from 98.5 to 149 micrograms/l in males and from 73.7 to 114 micrograms/l in children, the values decreasing as the distance from the source of emission increased. Cigarette smoking was found to bring about a significant increase in Pb-B levels for both males and females. A significant correlation was noted between Pb-B concentrations in mothers and children. The ratio between child and maternal Pb-B concentrations amounted to approximately 1.0 for group I and to about 0.5 for group II. These findings indicate the necessity of undertaking preventive activities over the lead-contaminated areas. However, the lead hazard in Poland seems to be associated with point sources of emission and hence does not concern the whole population.

Geltape method for measurement of work related surface contamination with cobalt containing dust: correlation between surface contamination and airborne exposure

OBJECTIVES

The geltape method is a new method for optical measurement of total amount of dust on surfaces. The objectives were to study the potential applicability of this method to measurements of work related cobalt exposure during painting of plates with cobalt dye.

METHODS

Consecutive series of work related geltape prints were taken from surfaces inside and outside the ventilation cabins of two plate painters during two full working days. The amount of dust picked up by the geltapes was measured optically with a field monitor. Also, personal air samples were collected on filters at the different work processes. In the laboratory the contents of cobalt on the geltape prints and the filters were measured with inductive coupled plasma atomic emission spectroscopy.

RESULTS

The key results were: (a) when the geltape prints were taken from surfaces inside the cabins the optically measured area of the geltapes covered with total dust (area (%)) correlated well with the chemically measured amount of cobalt present on the geltapes. Linear correlation coefficient (R2) was 0.91 for geltape prints taken on the floor and 0.94 for prints taken on the ceiling; (b) the cumulative airborne cobalt exposure, calculated from data on work related exposure by personal sampling, correlated with the area (%) of geltape prints taken from the ceiling of the cabin (R2 = 0.98); (c) the geltape method could be used to distinguish both between work processes with different levels of cobalt exposure, and between plate painters subjected to significant differences in airborne cobalt exposure.

CONCLUSION

The geltape method could produce measures of the work related exposures as well as whole day exposure for cobalt. The geltape results correlated with measurements of personal airborne cobalt exposure. In this industry the profile of exposure is well-defined in time, and it seems reasonable to apply this fast and low cost method in routine exposure surveillance to obtain a more detailed description of the exposure than can be obtained by the use of airborne measurements only.

Human exposure to toxic metals: factors influencing interpretation of biomonitoring results

An important approach to assessment of risk from environmental and occupational exposures is biomonitoring which provides an estimate of the total dose absorbed and gives indirect access to determination of target site concentrations. It is also a tool for assessing residual exposure, when respiratory protection is used. The interest in biological effects from toxic metals has increased during the last decades, as large amounts of metals have been released into industrial areas, and it is estimated that approximately 150,000 Danish workers are exposed to various metals. Since biomonitoring results play an important role in decision-making regarding great health and economic impact, understanding the factors influencing validity of such data is essential. In the present survey, the toxic elements arsenic, cadmium, chromium, cobalt, lead and nickel are used as examples to illustrate the disturbing factors in the interpretation of biomonitoring results. The aim of collecting samples is to obtain a small and representative sample of subjects or of a subpopulation being investigated for specific purposes, e.g. the pollution at Mundelstrup, where arsenic exposure of inhabitants and workers engaged in removing contaminated soil was monitored. As exposures vary over time and between subjects, it should be recognized that sampling as well as analytical variations contribute both to bias and random errors. Also biomonitoring data are a function of demographic, lifestyle and geographic factors. Therefore, stratified sampling designs are of the utmost importance. Half-lives play an important role. For short half-lives below 10 h, no decision can be made on long-term exposure if only one urine sample has been taken. For arsenic, cobalt, chromium and nickel in urine measured at the end of a workweek (t1/2: 20-100 h), 2-3 samples should be taken to monitor a single worker, and the results should be interpreted from the average of the results. For groups of workers, it is recommended that results from at least 5-10 workers be used to obtain a useful group mean value. In general, pharmacokinetics modelling contributes to information on sampling time and sampling size. Intake of cobalt in mineral tablets containing soluble cobalt compounds was a factor with a large influence on blood and urinary levels. Age and gender influence the blood and urine concentrations of arsenic, cadmium, cobalt and lead, e.g. B-Pb in females is 20-30% lower than B-Pb in males.(ABSTRACT TRUNCATED AT 400 WORDS)

Estimation of reference values for urinary 1-hydroxypyrene and alpha-naphthol in Danish workers

In order to assess environmentally and occupationally related exposures to PAH compounds it is essential to have reference or normal values in human body fluids. The establishment of reliable reference intervals is an absolute pre-requisite in determining relationships between internal PAH exposure in humans and health effects in occupationally exposed workers. In this context the estimation of the biological level of PAH metabolites in urine from reference populations has become increasingly important in the field of environmental and occupational toxicology. The present study describes the calculation of tentative reference values for urinary 1-hydroxypyrene on the basis of two reference populations and for urinary alpha-naphthol on the basis of one reference population in accordance with IFCC recommendations. The study subjects were 115 healthy male workers occupationally exposed to PAH at low levels and 121 reference subjects non-occupationally exposed to PAH. Tentative reference values for urinary 1-hydroxypyrene were estimated. In addition, 236 healthy male workers were used to estimate tentative reference values for urinary alpha-naphthol. The reference populations were described by distribution free one-sided tolerance intervals. The 95% one-sided tolerance limit calculated for 1-hydroxypyrene in urine was 0.053 mumol/mol creatinine for non-occupationally exposed individuals and 0.169 mumol/mol creatinine for low level PAH exposed workers, with the coverage interval (95 +/- 4.5) percent at a probability of 0.95. Thus, the probability was 0.975 that the tolerance interval included at least 90.5% of the distribution. In addition, the probability was 0.025 that the tolerance interval included > 99.5% of the population. The tolerance interval for alpha-naphthol in urine was 5.665 mumol/mol creatinine with the coverage interval (95 +/- 4.5) percent at a probability of 0.95.

Assessment of long-term styrene exposure: a comparative study of a logbook method and biological monitoring

In a recent joint European research project "Biomonitoring of human populations exposed to genotoxic environmental chemicals: biomonitoring of styrene exposed individuals", a logbook method for assessment of long-term styrene exposure was applied in two Danish factories manufacturing glass fibre-reinforced polyester. The method was based on work process identification, assignment of work process concentrations and logbook keeping. Measures of exposure calculated by this method were compared with results from simultaneous measurements of styrene in blood and the metabolites mandelic acid and phenylglyoxylic acid in urine. Correlations were comparable with those obtained by use of personal samplers as published in the literature. Styrene in blood, however, only correlated with logbook concentrations at the time of sampling. Exposures were moderate to low. Mean personal 8-h time-weighted average concentration (8hTWAC) was 76 mg/m3 styrene (SD 54 mg/m3, range 2-230 mg/m3). The Danish 8hTWAC threshold limit value for styrene in air, 105 mg/m3 (25 ppm), was exceeded on 17% of personal days. The summed urinary metabolites, mandelic acid and phenylglyoxylic acid, had a mean personal value of 138 mg/g creatinine (SD 84 mg/g creatinine) on the day of sampling. Blood styrene mean value was 129 micrograms/l (SD 74 micrograms/l, range 66-358 micrograms/l). It is concluded that the logbook method offers a technique for testing whether measurements are performed on representative days and may be recommended as a tool supplementary to biological monitoring in the assessment of long-term exposure.

A 1982-1992 surveillance programme on Danish pottery painters. Biological levels and health effects following exposure to soluble or insoluble cobalt compounds in cobalt blue dyes

This paper provides a short overview of cobalt-related diseases with particular reference to the potential carcinogenicity of cobalt compounds, and a review of a 10-year surveillance programme on plate painters exposed to cobalt in two Danish porcelain factories. Clinical experience and epidemiological studies have demonstrated that cobalt exposure may lead to severely impaired lung function, i.e. hard metal lung disease and occupational cobalt-related asthma, contact dermatitis and cardiovascular effects. However, the evidence for the carcinogenicity of cobalt and cobalt compounds is considered inadequate (IARC, 1991). Most frequently, exposure to cobalt occurs simultaneously with exposure to other elements known to pose a health risk, (e.g. nickel, arsenic, chromium, tungsten). The importance of cobalt as sole causal agent in hard metal lung diseases, cardiomyopathy and cancer are still a matter of controversy. In the two Danish porcelain factories, cobalt blue underglaze dyes have been used since 1888. In contrast to the exposure experience of hard metal factories, the exposure of plate painters occurs with only low trace levels of other potentially harmful compounds such as the carcinogenic metals nickel, arsenic and chromium. Consequently, the nearly-pure cobalt exposure makes the plate painters an attractive group for studies on the health effects of cobalt. During the period 1982-1992 the surveillance programme showed a profound reduction in the urine level of cobalt (Co-U) from 100-fold to 10-fold above the median level of the unexposed control subjects. In the same period, the airborne cobalt exposure declined from 1356 nmol/m3 to 454 nmol/m3, the Danish occupational exposure limit being 845 nmol/m3. In 1982, when the cobalt exposure was above the occupational exposure limit, the plate painters showed a chronic impaired lung function. The obstructive effects may be similar to some of the effects observed in hard metal workers. In 1988, a study on the effect of cobalt exposure at low levels revealed no inhibitory effects on thyroid function, but the ratio between T4 and T3 increased, indicating that low cobalt exposure may have an impact on the metabolism of thyroid hormones. Parallel studies were conducted on the metabolism and excretion of cobalt. The gastrointestinal uptake of soluble CoCl was considerably higher than the uptake of insoluble cobalt(II) oxide. In addition, it was demonstrated that ingestion of controlled amounts of the soluble cobalt compound resulted in significantly higher concentrations of cobalt in urine and blood (Co-B) from females compared with males (P < 0.01). Future studies will involve epidemiology and genotoxicity to evaluate the previous and present cancer risk, and detailed process-related exposure assessment studies to select the methods most reliable for surveillance of low-dose cobalt exposure.

Correlation between work process-related exposure to polycyclic aromatic hydrocarbons and urinary levels of alpha-naphthol, beta-naphthylamine and 1-hydroxypyrene in iron foundry workers

In two Danish iron foundries the concentration of polycyclic aromatic hydrocarbons (PAH) in 24 personal air samples of workers employed in selected processes, i.e. melters, melted iron transporters, casters, machine molders, hand molders, shake-out workers and finishing workers, were measured and correlated to levels of 1-hydroxypyrene, alpha-naphthol and beta-naphthylamine in the urine of exposed workers. The highest total airborne PAH concentrations (sum of 15 selected PAH compounds: 9.6-11.2 micrograms/m3) were associated with casting, machine molding, and shake-out. The highest concentrations of the sum of six selected airborne carcinogenic PAH compounds were found for melting, casting and machine and hand molding. As seen in other working environments involving low-level PAH exposure, the content of naphthalene was high, in general exceeding 85% of the total content of PAH compounds. The present study demonstrates that 1-hydroxypyrene is a useful and direct biomarker of low-dose occupational exposure to PAH compounds. Molding and casting had the highest pyrene levels in iron foundries. Furthermore, the data shows that levels of beta-naphthylamine in urine are significantly elevated in iron foundry workers. Hand molders, finishing workers and truck drivers tended to have the highest levels. Concerning alpha-naphthol the highest concentrations were measured in urine from casters and shake-out workers. With regard to epidemiologic studies demonstrating that molders and casters have a higher risk of lung cancer, the present study suggests that the elevated risk may be due to exposure to carcinogenic PAH compounds in iron foundries, particularly in some high-risk work processes, e.g. casting and molding. In addition, the present study suggests that biological monitoring of 1-hydroxypyrene and beta-naphthylamine may be used to estimate the individual exposure, which seems to be correlated with exposure during individual work processes.

Determination of the urinary metabolites of styrene: estimation of the method evaluation function and evaluation of reference values in Danish subjects

A European study on styrene exposure was initiated in 1989 to evaluate the health effects of environmental and occupational exposure. A part of this study included the development of an analytical method for use in a biological monitoring program. The urinary metabolites of styrene, mandelic acid (MA) and phenylglyoxylic acid (PGA) were quantitated by a direct and convenient high-performance liquid chromatography method. Urine samples were diluted with eluent and analysed by HPLC with a C8 reversed-phase column and a buffer to acetonitrile (9:1) eluent with a counterion added. The detector used was a variable UV detector and the wavelength was lambda = 210 nm. The method was statistically evaluated by a method evaluation demonstrating no systematic error. The uncertainty was 23.8 mumol/l and 11.5 mumol/l for MA and PGA, respectively. The limit of detection (LOD) of MA is 71.4 mumol/l and the LOD of PGA is 34.5 mumol/l, sufficiently low for the measurement of styrene exposure at a low exposure level. The present study indicates that reference values for MA and PGA are low. The fraction of reference values below LOD was 0.80 for MA and 0.66 for PGA; consequently, the reference values were described by a non-parametric one-sided tolerance interval. The 95% one-sided upper tolerance limits calculated for MA and PGA were 31.0 mumol/mmol creatinine and 20.1 mumol/mmol creatinine, respectively, with the coverage 0.95 +/- 0.045 for both metabolites. The method has been used for biological monitoring in several studies of environmentally and occupationally exposed subjects in concentrations up to 200 mumol/mmol creatinine for MA and 150 mumol/mmol creatinine for PGA.

Trace element reference values in tissues from inhabitants of the European Community. V. Review of trace elements in blood, serum and urine and critical evaluation of reference values for the Danish population

The availability of accurate trace element reference values in human tissues represents an important indicator to the health status of the general population and occupational groups exposed to trace elements. The EURO TERVIHT project (Trace Element Reference Values In Human Tissues) aims to establish and compare trace element reference values in tissues from inhabitants of the European Community as baseline values for clinical/toxicological assessment studies (Sabbioni et al., 1992, Sci. Total Environ., 120: 39-62). In this context, one of the first steps considered is the critical evaluation (state of the art) of existing literature on trace element reference values in blood, serum and urine in the general population of each EC country. This paper reviews the Danish situation.

A short-term cross-over study on oral administration of soluble and insoluble cobalt compounds: sex differences in biological levels

This paper describes a blind cross-over study on the gastrointestinal uptake of soluble and insoluble cobalt compounds (8.5 mumol/day) in 12 male and 11 female volunteers. In a controlled study it was found that the gastrointestinal uptake of the soluble cobalt compound cobalt chloride was considerably higher than the uptake of the insoluble cobalt compound cobalt oxide (urine ranges: < 0.17-4373 and < 0.17-14.6 nmol/mmol creatinine, respectively). Surprisingly, it was shown that ingestion of controlled amounts of soluble cobalt compound resulted in significantly higher urinary cobalt levels (P < 0.01) in females (median: 109.7 nmol/mmol creatinine) than in males (median: 38.4 nmol/mmol creatinine). The results suggest that the gastrointestinal uptake of cobalt is higher for females than males. The present study shows that the normal levels of cobalt in blood and urine in a non-random-selected group of Danes are low. As the fraction of values below the detection limit of the analytical method was 0.19 and 0.33 for urinary cobalt in females and males, respectively, distribution-free one-sided tolerance intervals were chosen to describe the values. The precision of the estimate of the tolerance intervals was expressed as coverage intervals. In females the 95% one-sided tolerance limit calculated for cobalt in blood and urine was 8.48 and 55.10 nmol/l with coverage intervals of 90% +/- 6.5% and 95% +/- 4.2% at a probability of 0.95, respectively. Even though the studied groups of males and females were not representative for the general population, the study indicates that oral exposure may be important in occupational settings.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of chromium in blood and serum: evaluation of quality control procedures and estimation of reference values in Danish subjects

This paper describes analytical methods to estimate environmental and occupational exposure levels of chromium in blood and serum by Zeeman atomic absorption spectrometry. Also reported is an internal quality control procedure involving a combination of an online quality control and subsequent statistical evaluation of the quality control results to evaluate the performance of the analytical methods. The solubilization of the blood by the proteinase Subtilisin A resulted in a recovery of chromium of 106 +/- 4.5%; the uncertainty was approximately 10% at a chromium level of 1 microgram l-1. The detection limit (LOD) for chromium in serum was 0.17 micrograms l-1 and 0.20 micrograms l-1 for chromium in blood. The LODs were sufficiently low for the determination of chromium in a large fraction of reference populations not occupationally exposed. The present study indicates that reference values for chromium in blood and serum are low but within the range in recent investigations, i.e. 0.04-0.35 micrograms l-1 in serum and 0.12-0.34 micrograms l-1 in human whole blood. The fraction of reference values below LOD was between 0.45 and 0.57 for chromium in serum and blood. Consequently, the reference populations were described by distribution free one-sided tolerance intervals and the precision of the estimation of the tolerance intervals was expressed as coverage intervals. The 95% one-sided tolerance limit calculated for chromium in serum was 0.60 micrograms l-1 with the coverage interval (95 +/- 4.8) percent at a probability of 0.95. Thus, the probability was 0.975 that the tolerance interval covers at least 90.2% of the distribution. In addition, the probability was 0.025 that the tolerance interval covers more than 99.8% of the population. It was only possible to calculate the 90% tolerance interval for chromium in blood with the coverage interval at 0.90 probability. The one-sided tolerance interval for chromium in blood was 0.37 micrograms l-1 with the coverage interval (90 +/- 9.9) percent at a probability of 0.90.

Danish external quality assessment scheme: an interlaboratory comparison study on lead, cadmium and chromium in lyophilized human blood concentrate

A Danish External Quality Assessment Scheme (EQAS) was carried out by the Danish National Institute of Occupational Health during the period 1988-1992. The scheme was implemented for 29 international laboratories from 15 countries assaying lead, cadmium, and chromium in human blood to ascertain the systematic error and uncertainty of the analytical methods. In the survey the quality control material AMI B701-B705, based on lyophilized human whole-blood concentrate, were used. As an estimate of the true values the reference values used in this evaluation were (a) the computed values, i.e., sum of the basal and spiked trace element concentration, and (b) the consensus values normally used in the Danish EQAS. This international evaluation of lead, cadmium, and chromium in human blood demonstrated that the use of lyophilized human blood concentrate quality control materials combined with this scheme is valuable in estimating the systematic error and the uncertainty of the analytical methods. For evaluating analytical performance, the computed values were preferable to the consensus values for lead and cadmium in human blood. Due to analytical difficulties suitable reference values were not established for chromium in blood. The study revealed analytical difficulties for cadmium and chromium in human blood. The assessment of laboratories according to established performance indexes indicates that few laboratories can maintain these performance indexes.

Determination of 1-hydroxypyrene in human urine by high-performance liquid chromatography

A high-performance liquid chromatography (HPLC)/fluorescence method for quantitative analysis of 1-hydroxypyrene in urine was developed. The method validation analysis showed the method to be in analytical control. No significant systematical errors could be demonstrated. The entire run time of chromatography was 10 min using isocratic elution (acetonitrile-water, 70:30), and the retention time for 1-hydroxypyrene was 3.5 min. The short run time in combination with the low limit detection (1.37 nmol/L) makes the method potentially applicable for surveillance of pyrene exposure in work environments. The developed method is presently used for measurement of 1-hydroxypyrene in urine samples from workers exposed to a low airborne level of polycyclic aromatic hydrocarbons, generally less than 25 micrograms/m3. The urine samples of exposed workers (n = 122) showed a range of 1-hydroxypyrene from the limit of detection (LD) up to 39 nmol/L, whereas unexposed control individuals (n = 108) showed a range from LD to 3.3 nmol/L.

Determination of 2-naphthylamine in urine by a novel reversed-phase high-performance liquid chromatography method

A high-performance liquid chromatographic method for the determination of 2-naphthylamine in urine using fluorescence detection was developed. The method validation analysis showed the method to be in analytical control, i.e. the distribution of the difference between the observed and true values of the method evaluation samples did not deviate significantly from the normal distribution. The recovery of the method was 85%. The entire run time of chromatography was 10 min using isocratic elution (acetonitrile-water, 35:65), and the retention time for 2-naphthylamine was 5.8 min. The relative short time of analysis in combination with the low limit of detection (0.272 nmol/l) makes the method potentially applicable for surveillance of occupational and environmental exposure to 2-nitronaphthalene. The developed method is presently used for measurement of 2-naphthylamine in urine samples from workers employed at factories, characterized by a low airborne exposure level of polycyclic aromatic hydrocarbons, i.e. in general less than 25 micrograms/m3. The urine samples of exposed workers (n = 95) showed a 2-naphthylamine range of up to 9.4 nmol/l, whereas unexposed control individuals (n = 114) showed a range of up to 0.87 nmol/l.

Effectiveness of an oral enteric coated vibrio vaccine for use in salmonid fish

An oral enteric-coated Vibrio anguillarum vaccine was developed by initially coating lyophilized bacteria onto 0.9 mm diameter dextrose sugar beads followed by an Eudragit L-30D coat to serve as enteric protection. Vaccine efficacy was determined by both an in vivo challenge with live pathogen and measurements of serum and mucus antibody levels by ELISA. Survival rates after challenge were 80.3%, 83.3% and 70.3% among the vaccine group, positive and negative controls respectively. Serum and mucus antibody levels were found to be significantly greater in the vaccine group (p less than 0.01). In cases where equivalent survival among tested groups is observed, determination of antibody titer by ELISA may be a preferable indicator of vaccine efficacy.

Biomonitoring of genotoxic exposure among stainless steel welders

A biosurvey in the Danish metal industry measured the genotoxic exposure from stainless steel welding. The study comprised measurements of chromosomal aberrations (CA), sister-chromatid exchanges (SCE), unscheduled DNA synthesis (UDS) in peripheral lymphocytes and serum immunoglobulin G. Environmental monitoring of welding fumes and selected metal oxides, biomonitoring of chromium and nickel in serum and urine and mutagenic activity in urine, and evaluation of semen quality were also done. Manual metal arc (MMA) welding and tungsten inert gas (TIG) welding were the dominant welding processes. A higher frequency of chromosomal aberrations, classified as translocations, double minutes, exchanges and rings, was observed in stainless steel welders than in non-welders. SCE was lower in welders working with both MMA and TIG welding than in reference persons. N-Acetoxy-N-acetylaminofluorene (NA-AAF)-induced UDS was lower in 23 never-smoking welders than in 19 unexposed never-smokers. Smoking was a confounding factor resulting in significantly higher CA, SCE, NA-AAF binding to DNA and mutagenic activity in urine. Age was also a confounder: CA, SCE, NA-AAF binding to DNA and UDS increased significantly with age. No significant correlation between SCE and CA or between CA and UDS was found. UDS decreased significantly with increasing lymphocyte count and a higher lymphocyte count was seen in MMA welders than in reference persons and in smokers than in non-smokers. Differences in the composition among lymphocytes in exposed persons compared with non-exposed are suggested. MMA welding gave the highest exposure to chromium, an increased number of chromosomal aberrations and a decrease in SCE when compared with TIG welding. Consequently improvements in the occupational practice of stainless steel welding with MMA is recommended.

Effect of occupational exposure to cobalt blue dyes on the thyroid volume and function of female plate painters

It has previously been shown that long-term oral exposure to cobalt can cause goiter and myxedema. The effect of industrial cobalt exposure on thyroid volume and function was determined for 61 female plate painters exposed to cobalt blue dyes in two Danish porcelain factories and 48 unexposed referents. Thyroid volume was determined by ultrasonography. The cobalt blue dyes were used in one of two forms, cobalt aluminate (insoluble) and cobalt-zinc silicate (semisoluble). Only the subjects exposed to semisoluble cobalt had a significantly increased urinary cobalt content (1.17 micrograms.mmol-1 versus 0.13 micrograms.mmol-1, P less than 0.0001). These subjects also had increased levels of serum thyroxine (T4) and free thyroxine (FT4I) (P = 0.0001 and 0.0029, respectively), unaltered serum thyroid stimulating hormone (TSH), and marginally reduced 3,5,3'-triiodothyronine (T3), whereas thyroid volume tended to be lower (P = 0.14). The group exposed to insoluble cobalt did not differ significantly in any thyroid-related parameters. No correlation between urinary cobalt and FT4I or thyroid volume was found. The study demonstrates an effect of cobalt on thyroid hormone metabolism.

Effect of seafood consumption on the urinary level of total hydride-generating arsenic compounds. Instability of arsenobetaine and arsenocholine

Arsenobetaine and arsenocholine are considered to be non-toxic and are present as a relatively large proportion of total arsenic in seafoods, and they do not respond to hydride generation. The present study describes the effect of seafood consumption on the urinary concentration of hydride-generating arsenic compounds measured by a newly developed flow injection atomic absorption spectrometric (FI-AAS) method. Consumption of plaice, pighvar and tunny resulted in a 2-fold increase, and consumption of mussels produced a 6-fold increase in the urinary level of hydride-generating arsenic compounds. Hence, a person who has consumed mussels may be suspected of being occupationally or environmentally exposed, if the level of consumption of this seafood is unknown. As the FI-AAS method cannot be used to detect arsenobetaine and arsenocholine, the observed increase in urinary concentration of hydride-generating arsenic compounds after consumption of seafood must originate either from hydride-generating arsenic compounds in the seafood or from degraded arsenobetaine or arsenocholine. The present study has demonstrated that both arsenobetaine and arsenocholine are unstable when incubated in daylight in the presence of hydrogen peroxide, i.e., an oxidizing environment. Hence, it is tempting to speculate that arsenobetaine could be converted into hydride-generating arsenic compounds during storage or cooking of seafood. The feasibility of speciation methods based on high-performance liquid chromatographic (HPLC) separation and on-line analysis by inductively coupled plasma atomic emission spectrometry (ICP-AES) and FI-AAS was also investigated. The FI-AAS system is approximately 35 times more sensitive to the hydride-generating arsenic species than the ICP-AES system.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative study of certified reference materials and quality control materials for the quality assurance of blood-lead determination

In order to ensure a high standard in the analytical methods used to determine lead in blood, reference materials, quality control materials and several quality assessment schemes exist. However, since 1988 the blood lead level in the European Community has decreased owing to a decline in environmental and occupational exposure; consequently there is a need for certified reference materials (CRMs) at low level. A study of the biological CRMs for blood lead, CRMs 194-196 from the European Community Bureau of Reference (BCR) and the quality control materials STE 901-906 from Nyegaard A/S, and AMI B601-B604 and AMI B701-B705 from the Danish National Institute of Occupational Health (AMI), was made in order to evaluate the control materials AMI B701-B705 against the CRMs 194-196, and to verify the homogeneity and influence of the biological matrix of commercially available blood-lead quality control materials. Internal quality control data were collected and an interlaboratory study was carried out on lyophilized human blood versus lyophilized bovine blood certified for lead. The calculated standard deviations for the BCR CRMs were comparable to the standard deviations for AMI control materials, although the biological matrix was different. No significant difference was demonstrated between the blood-lead levels certified by BCR in 1985 and the levels measured by AMI in 1991, indicating the homogeneity and stability of the lyophilized materials. All analytical results were obtained from selected international laboratories by using atomic absorption spectrometry and anodic stripping voltammetry. The study emphasizes the need for CRMs, control materials and quality assessment schemes for trace elements in biological fluids.(ABSTRACT TRUNCATED AT 250 WORDS)

[Assessment of the health risk of a residential area contaminated with arsenic and lead. Biological monitoring in Mundelstrup]

Industrial use of toxic substances has resulted in contamination of the outer environment so that polluted area now constitutes a considerable environmental problem. This article describes biological monitoring employed as part of the basis for assessment of the health risk due to contaminated housing soil. As an example was chosen the environmental contamination with lead and arsenic in Mundelstrup Station Town, where a manure factory previously was situated. This area, which was found to be contaminated to a considerable extend with lead and arsenic, was subdivided for living area in 1921. The present material includes 99 residents from a housing area with 30 family houses with gardens in Mundelstrup. At the commencement of the investigation in 1988/1989, blood lead levels and arsenic levels in the urine were measured and the latter were repeated in 1989/1990. For both adults and children, the blood lead levels were the same as in the reference populations. Children below 12 years had in the average higher arsenic contents in the urine compared with women and men: 16.3 mu/l 8.6 mu/l and 11.5 mu/l, respectively. For both children and adults, the arsenic values were similar to those in a limited Danish reference population. In Ruston, an area in USA heavily polluted with arsenic, contamination of the surface was found to correspond to a factor ten times higher than in Mundelstrup where arsenic is measured at a deeper level. Correspondingly, arsenic values in the urine revealed higher average values in children, 30 micrograms/l for females and 65 micrograms/l for males. The average values for the reference group were found to be 11.3-13.0 micrograms/l.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlation of levels of volatile versus carcinogenic particulate polycyclic aromatic hydrocarbons in air samples from smokehouses

In the present study, data on the concentration of polycyclic aromatic hydrocarbons (PAH) in air samples from fish smokehouses (Nordholm et al. 1986) and meat smokehouses (Hansen et al. submitted for publication) were used to analyze the extent to which six different volatile PAH compounds could function as markers for the total concentration of six different carcinogenic particulate PAH compounds. Although a significant positive correlation was observed between the concentration of each of six volatile compounds and the total concentration of carcinogenic PAH compounds, a particularly good correlation was observed for phenanthrene, anthracene, fluoranthene and pyrene. Calculations of the sensitivity, specificity, positive predictive value and negative predictive value of these potential markers revealed that naphthalene and phenanthrene exhibited the highest sensitivity as markers for total carcinogenic PAH compounds in air samples from smokehouses, whereas fluoranthene and pyrene displayed the highest specificity. However, when the applicability of the six markers was tested on air samples from iron foundries, only naphthalene and pyrene were useful as markers for the carcinogenic compounds. The present study indicates that naphthalene and pyrene might function as markers for carcinogenic PAH compounds, that are present at low concentrations and are therefore difficult and time-consuming to measure directly.

Chromium in biological samples from low-level exposed stainless steel and mild steel welders

Occupational exposure to hexavalent chromium is of concern because of the carcinogenic action of this metal. The purpose of this study was to evaluate internal exposure to chromium in welders who were exposed to low levels of chromium. Chromium in urine, blood, and seminal fluid was determined among 60 welders and 45 referents. The concentration of chromium in urine and blood did not change across a workshift or across a 3-wk break in exposure. However, stainless-steel and mild-steel welders who were exposed to low levels of chromium and steel welders who were mildly exposed had significantly increased levels of chromium in post-shift urine (mean 2.1 nmol/mmol creatinine [standard deviation (SD) = 1.0] and 1.3 nmol/mmol creatinine [SD = 0.5], respectively) compared with referents (mean 0.7 nmol/mmol creatinine [SD = 0.3]). Pre-shift blood chromium concentrations showed a similar variation between exposed workers and referents. Subgroups of stainless-steel welders had very high levels of chromium in seminal fluid. This finding may, however, be explained by nonoccupational factors and, therefore, warrants further study. Attention should focus on the potential risk of delayed health effects among stainless-steel and mild-steel welders who heretofore were not thought to be at risk from chromium exposure.

Ibuprofen piconol hydrolysis in vitro in plasma, whole blood, and serum using different anticoagulants

Hydrolysis kinetics of ibuprofen piconol to ibuprofen were determined in vitro in plasma, whole blood, and serum. Varying initial concentrations of ibuprofen piconol with different anticoagulants (EDTA, heparin, citrate, or no anticoagulant) were used in determining the effects each had on the rate of ibuprofen piconol hydrolysis. Varying the initial concentration of ibuprofen piconol did not alter the hydrolysis half-life (concentration range from 50 to 200 micrograms/mL). The anticoagulant used altered the hydrolysis half-life. For plasma, the half-life was shortest when no anticoagulant was present (t 1/2 = 2.5 h) and longer with the presence of anticoagulants; for citrate, t 1/2 = 8.0 h, for heparin; t 1/2 = 15.5 h; and for EDTA, t 1/2 = 161.8 h. Red blood cell uptake of ibuprofen piconol was minimal and ranged from 0.4 to 4.1% over the ibuprofen piconol concentrations used in the study.

Bleomycin-iron complexes and DNA radiation damage

Radiation in the form of high-energy electrons dose-dependently activates bleomycin-Fe3+ in oxygen-containing DNA solutions. This activation causes a DNA fragmentation and a release of oxidative degradation products from the DNA. During irradiation, bleomycin-chelated Fe3+ is reduced to Fe2+. The kinetics of DNA base propenal-formation (measured by reaction with thiobarbituric acid) and iron-reduction (measured by bathophenanthroline chelation) are similar, with a yield of 1 mol base propenal/6 mol Fe3+ reduced. The activation of bleomycin-Fe3+ by irradiation could be instrumental in the synergistic action of radiotherapy and bleomycin observed on simultaneous administration in vivo.

Blood lead-blood pressure relations: alcohol intake and hemoglobin as confounders

A cohort of 1,052 persons (504 men and 548 women) born in 1936 and residing in the Glostrup area, Denmark, underwent a comprehensive physical examination in 1976 at age 40 years, and 966 underwent a complete reexamination five years later. The examinations included blood lead concentration and blood pressure assessment under careful quality control. Complete blood lead and blood pressure data were available for 861 of these subjects (451 men and 410 women). The median blood lead levels were 13 and 9 micrograms/100 ml at age 40 years and 9 and 6 micrograms/100 ml at age 45 years in men and women, respectively. A slightly increased blood lead concentration was seen at age 40 years in women with a systolic blood pressure above 140 mmHg and/or a diastolic blood pressure above 90 mmHg. Systolic blood pressure in men and women and diastolic blood pressure in women correlated significantly with log blood lead at age 40 years but not at age 45 years, a doubling in blood lead being associated with an increase in blood pressure of 3 mmHg or less. Of nine potential confounders assessed, only blood hemoglobin and alleged alcohol intake were significantly associated with both blood lead and blood pressure. If one or both confounders were entered into a multiple regression analysis, all associations between blood lead and blood pressure became nonsignificant, in some cases with a negative regression coefficient. In addition, the blood lead:hemoglobin ratio was poorly associated with blood pressure, particularly in individuals with a low alcohol intake. Because both hemoglobin level and alcohol intake appear to be biologically plausible confounders, any independent effect of low-level lead exposure on blood pressure could not be determined.

Health effects due to occupational exposure to cobalt blue dye among plate painters in a porcelain factory in Denmark

Forty-six plate painters, heavily exposed to cobalt blue dye, took part in this cross-sectional study, and 51 top-glaze painters served as the referents. The study comprised a questionnaire, a health examination, a lung function test, and the determination of the blood and urinary cobalt levels. The plate painters were examined twice, at the end of a workfree period and after resuming work. More plate painters complained of irritation from the mucous membranes in the mouth and throat, cough, and expectoration than the referents. The symptoms increased after the plate painters resumed work. The cobalt level of the plate-painting group after six weeks off work was twice as high in the blood and five times higher in the urine than the corresponding values of the reference group. After the plate painters resumed work, the blood and urinary levels increased approximately 4 and 15 times, respectively. Increased airflow resistance was found in the plate group when compared with the referents, and signs of small airway obstruction increased after the plate painters resumed work. The pulse rate was higher among the plate painters, and minor changes in the red blood cell picture were observed. None of these adverse health effects were associated with the cobalt levels in the blood or urine.

Determination of trichloroethylene metabolites in rat liver homogenate using headspace gas chromatography

An headspace gas chromatographic (HSGC) method for determination of trichloroethylene metabolites in rat liver homogenates is described. These metabolites are chloral hydrate (CH), trichloroethanol (TCE), trichloroacetic acid (TCA) and the glucuronic acid conjugate of trichloroethanol (TCE-beta-glucuronide). The method is based on selective thermal conversion of CH and TCA into chloroform, which is determined together with trichloroethanol by HSGC using electron-capture detection. TCE-beta-glucuronide was determined as the difference between free TCE and total TCE after enzymatic hydrolysis with beta-glucuronidase. Synthesized TCE-beta-glucuronide was used to compare the efficiency of enzymatic and acid hydrolysis of the conjugate. Enzymatic hydrolysis was found to be advantageous for determination of TCE-beta-glucuronide.

Automatic headspace gas chromatographic method for the simultaneous determination of trichloroethylene and metabolites in blood and urine

Trichloroethylene, trichloroethanol and trichloroacetic acid (TCA) were quantitated in blood and urine by automated headspace gas chromatography using a fused-silica capillary column coated with 3-micron silicone SE-30 and an electron-capture detector. Total trichloroethanol was determined after enzymatic hydrolysis with beta-glucuronidase and analysed together with trichloroethylene and TCA as chloroform, which are produced by decarboxylation. Analytical conditions were developed under which the thermal decomposition of TCA was optimal. The automated headspace gas chromatography is rapid and good precision is possible. Sample preparation is simple and the sensitivity of the procedure (0.02 microgram/ml) makes it suitable to estimate occupational exposure to trichloroethylene and other halocarbons in humans.

Concentration of nickel and chromium in serum: influence of blood sampling technique

In the determination of nickel and chromium in serum, contamination is the most important source of error. In this study the influence of needle type and collection device was investigated. For each of 20 subjects the concentrations of nickel and chromium in serum obtained by the following techniques of blood collection were compared: closed collection system (acidwashed polyethylene syringes) + (A) steel needle (Terumo), (B) teflon i.v. cannula (Abbocath-T), and (C1) teflon i.v. cannula (Venflon); (C2) open collection system (acidwashed polyethylene tubes) + teflon i.v. cannula (Venflon). For each technique the first 5 ml of blood were discarded. No statistically significant differences were found between serum concentrations of nickel and chromium in specimens collected with the sampling techniques A, B, C1 and C2. This study has shown that identical results for concentrations of nickel and chromium in serum are obtained independent of whether a steel needle or a teflon i.v. cannula is used for blood sampling, provided the first 5 ml of blood are discarded. Likewise, identical results are obtained independent of whether specimens are collected in a closed or an open collection system, provided collection devices are acidwashed and sampling takes place under hospital conditions.

Precipitate analysis from an indwelling total parenteral nutrition catheter

The composition of a precipitate obtained from a silastic right atrial catheter was determined. The precipitate was collected and washed with deionized water thoroughly before subjecting portions of it to organic and inorganic analysis. Inorganic analysis was conducted using scanning electron microscopy and x-ray spectroscopy for sodium, aluminum, silicone, sulfur, chlorine, and calcium. Phosphorus analysis was conducted by a commercial laboratory. Organic analysis was conducted by thin layer chromatography with cholesterol, phosphatidyl serine, phosphatidyl choline, phosphatidyl ethanolamine, and sphingomyelin as standards. Silicone, calcium, and phosphorus and three organic compounds, which could not be conclusively identified, were found. The precipitate was most likely calcium phosphate intermixed with silicone oil lubricant and residual total parenteral nutrition (TPN) solution. This formed in the catheter at body temperature probably due to incomplete catheter flushing.

Blood lead and erythrocyte zinc protoporphyrin in mothers and newborn infants

Blood lead (B-Pb) and erythrocyte zinc protoporphyrin (ZPP) were measured in 78 mothers at delivery and in cord blood from 48 infants living in an area with low atmospheric Pb pollution. Median B-Pb was 35 micrograms/l (range 6-63) in mothers and 20 micrograms/l (range 6-50) in infants (P less than 0.0001), and the values were significantly correlated (rs = 0.73, P less than 0.0001). Mean B-Pb infant/B-Pb mother ratio was 0.7 (range 0.2-1.4). Mothers had lower ZPP (median 1.6 microgram/g Hb) than infants (median 2.9) (P less than 0.0001). ZPP in mothers showed a stronger relation to iron status (serum transferrin, serum ferritin) than to B-Pb (rs = 0.22, P less than 0.05). B-Pb was correlated to serum iron both in mothers (rs = 0.28, P less than 0.02) and infants (rs = 0.33, P less than 0.03). The present B-Pb levels are lower than previously reported in Scandinavia, probably due to the general decline in atmospheric Pb pollution.

Effects of antacids and dialysate dwell times on multiple-dose pharmacokinetics of oral ciprofloxacin in patients on continuous ambulatory peritoneal dialysis

Six stable patients on continuous ambulatory peritoneal dialysis were evaluated for the appearance of ciprofloxacin in their peritoneal dialysate following oral ingestion of 750 mg of the drug every 12 h for four doses. Three subjects participated in this study twice, once while taking and once while abstaining from phosphate-binding aluminum antacids. Subjects tolerated the medication without evidence of toxicity. Food may have delayed or decreased the absorption of ciprofloxacin, whereas antacids definitely decreased the absorption of the drug. Peak concentrations in serum noted in the absence of antacids ranged from 2.9 to 6.4 micrograms/ml, and peak concentrations in dialysate in the absence of antacids ranged from 1.8 to 4.5 micrograms/ml. Peak ciprofloxacin concentrations in serum achieved in subjects taking antacids were 14 to 50% of those achieved in subjects without antacids. The peak concentrations in dialysate achieved in subjects on antacids were 8 to 33% of those observed in subjects off antacids. The clearance of ciprofloxacin by continuous ambulatory peritoneal dialysis represented 2% of the total body (systemic) clearance. Simultaneous ratios of concentration in dialysate to concentration in serum (D/S) were determined at various durations of dialysate dwelling within the peritoneum. A progressive rise of the D/S ratio was noted as dwell time increased. At 4 h D/S was 0.57 +/- 0.07 (mean +/- standard error of the mean; n = 9), and at 8 h it was 0.75 +/- 0.04 (n = 26). Long-dwell exchanges may be necessary to achieve reasonable concentrations of orally ingested ciprofloxacin in dialysate.

Serum ferritin and iron status in mothers and newborn infants

Iron status, including hemoglobin, S-ferritin, S-iron, S-transferrin, transferrin saturation and the erythrocyte zinc protoporphyrin/hemoglobin (ZPP:Hb) ratio, was evaluated in 85 healthy iron-supplemented mothers at parturition and in 74 of their term newborn infants. Of the mothers, 17% had a S-ferritin level less than 15 micrograms/l (i.e. depleted iron stores), 9.9% had S-ferritin less than 15 micrograms/l and transferrin saturation less than 15% (i.e. latent iron deficiency), and 2.4% had S-ferritin less than 15 micrograms/l, transferrin saturation less than 15% and Hb less than 120 g/l (i.e. iron deficiency anemia). Newborn infants had higher S-ferritin than mothers: median 128 micrograms/l versus 21 micrograms/l (p less than 0.0001), higher transferrin saturation: 48% vs. 21% (p less than 0.0001), and higher ZPP:Hb ratio: 74 mumol/mol Hb vs. 41 mumol/mol Hb (p less than 0.0001). During the first 5 post-natal days, median S-ferritin rose from 128 to 236 micrograms/l (p less than 0.0001). S-ferritin appeared to be the best single indicator of maternal iron status. Ferritin levels in newborn infants were correlated to levels in mothers (rs = 0.36, p less than 0.01), indicating that fetal iron reserves are dependent on maternal iron stores.

Pharmacokinetic disposition of dimethyl sulfoxide administered intravenously to horses

Dimethyl sulfoxide (DMSO) was administered IV to 6 Thoroughbred horses at 2 dosages: 1.0 g/kg and 0.1 g/kg. The pharmacokinetics seemed linear, with biological half-lives of 8.6 +/- 0.3 hours and 9.8 +/- 2.2 hours for the 1.0 g/kg and 0.1 g/kg dosages, respectively. This was further substantiated by mean residence times of 9.8 +/- 0.44 hours and 13.8 +/- 4.25 hours, areas under the curve of 12.55 +/- 1.42 mg/ml/hr and 1.63 +/- 0.49 mg/ml/hr, and the clearances of 0.081 +/- 0.009 L/kg/hr and 0.066 +/- 0.022 L/kg/hr for the large and small dosages, respectively. At 12 hours after 1.0 g/kg was administered, 26.6% of the DMSO dose was excreted unchanged into the urine; at 12 hours after 0.1 g/kg was administered, 25.3% of the DMSO dose was excreted unchanged into the urine. It was predicted that 29.4% and 40.6% of the total DMSO dose would be excreted into the urine for the 1.0 g/kg and 0.1 g/kg dosages, respectively. A 10% DMSO concentration in normal saline solution was safe to give as rapid IV infusion. Slow administration is recommended for more concentrated solutions. Based on the half-life, DMSO should be administered 2 times a day IV for the treatment of increased intracranial pressure and/or cerebral edema in horses.

Stability of levodopa in 5% dextrose injection at pH 5 or 6

The stability of solutions of levodopa 1 mg/mL in 5% dextrose injection adjusted to pH 5 or 6 and stored at one of three temperatures was determined. Solutions were adjusted to pH 5 or 6 with sodium acetate injection or sodium phosphate injection, respectively. Three samples of solution adjusted to pH 5 were stored at each of three temperatures (4, 25, and 45 degrees C), and three samples of solution adjusted to pH 6 were stored at 25 degrees C. Samples were assayed for levodopa concentration by high-performance liquid chromatography at various times during the 21-day study period. All solutions maintained at least 90% of the initial concentration of levodopa for seven days. Discoloration of all solutions except those stored at 4 degrees C was noted at some point during the study period; solutions stored at 45 degrees C began to darken within 12 hours. The pH values of the solutions did not change during the study period. Under the conditions studied, solutions of levodopa 1 mg/mL in 5% dextrose injection adjusted to pH 5 or 6 are stable for seven days. Slight degradation of levodopa may cause a brownish-black discoloration of the admixtures.