Detection of phytoestrogens in samples of second trimester human amniotic fluid

There is widespread concern that fetal exposure to hormonally active chemicals may adversely affect development of the reproductive tract. Therefore, the present study was performed to develop the necessary analytical methods and test the hypothesis that dietary phytoestrogens can be quantified in second trimester human amniotic fluid. Amniotic fluid samples (n=59) from women (n=53) undergoing routine amniocentesis between 15 and 23 weeks of gestation were analyzed by gas chromatography/mass spectrometric (GC/MS). Analytes included the phytoestrogens daidzein, genistein, formononetin, biochanin A, and coumestrol. Dietary phytoestrogens were quantified in 96.2% of second trimester amniotic fluid samples tested. The mean (+/- standard deviation (S.D.)) concentration of daidzein and genistein in amniotic fluid was 1.44 +/- 1.34 and 1.69 +/- 1.48 ng/ml with maximum levels of 5.52 and 6.54 ng/ml, respectively. Second trimester amniotic fluid contains quantifiable levels of dietary phytoestrogens and thus is a marker of mid pregnancy fetal exposure.     

Quantification of benzo[a]pyrene and other PAHs in the serum and follicular fluid of smokers versus non-smokers

Cigarette smoking is a well-established reproductive hazard that has been linked with decreased fertility in both smokers and those exposed to second hand smoke. The chemical components responsible for the reproductive toxic effects of cigarette smoke are unknown. Moreover, exposure of reproductive tissues to the chemical constituents of cigarette smoke is largely unknown. Therefore, we measured the levels of benzo[a]pyrene (B[a]P), and other polycyclic aromatic hydrocarbons (PAH) present in cigarette smoke, in the serum and follicular fluid of women exposed to mainstream (n=19) and side stream smoke (n=7) compared to non-smokers (n=10). Women exposed to mainstream smoke had significantly higher levels of B[a]P (1.32+/-0.68ng/ml) in their follicular fluid compared to side stream exposed (0.05+/-0.01ng/ml) or their non-smoking (0.03+/-0.01ng/ml) counterparts. More importantly we found significantly higher (p<0.001) levels of B[a]P in the follicular fluid of women who did not conceive (1.79+/-0.03ng/ml) compared to those that achieved a pregnancy (0.08+/-0.03ng/ml). Other PAHs known to be present in cigarette smoke were also detectable in both serum and follicular fluid of study subjects studied but with lower frequency compared to B[a]P and no differences in serum or follicular fluid levels between the groups could be demonstrated. The important finding that B[a]P reaches the follicular fluid and the fact that it is found at much higher levels in women who smoke provides further evidence that of the many toxicants present in cigarette smoke, B[a]P may be a key compound that is central to the documented adverse effects of cigarette smoke on follicular development and subsequent fertility.     

Effects of cigarette smoking and exposure to cadmium and lead on phenotypic variability of hepatic CYP2A6 and renal function biomarkers in men

Effects of cigarette smoking and exposure to dietary cadmium (Cd) and lead (Pb) on urinary biomarkers of renal function and phenotypic variability of cytochrome P450 2A6 (CYP2A6) were investigated in a group of 96 healthy Thai men with mean age of 36.7 year (19-57 years). In non-smokers, Cd burden increased with age (r = 0.47, P < 0.001). In current smokers, Cd burden increased with both age (r = 0.45, P = 0.01) and number of cigarettes smoked per day (r = 0.32, P = 0.05). Cd-linked renal tubular dysfunction was seen in both smokers and non-smokers, but Pb-linked glomerular dysfunction was seen in smokers only, possibly due to more recent exposure to high levels of Cd and Pb, as reflected by 30-50% higher serum Cd and Pb levels in smokers than non-smokers (P < 0.05). Exposure to dietary Cd and Pb appeared to be associated with mild tubular dysfunction whereas dietary exposure plus cigarette smoking was associated with tubular plus glomerular dysfunction. Hepatic CYP2A6 activity in non-smokers showed a positive association with Cd burden (adjusted beta = 0.38, P = 0.006), but it showed an inverse correlation with Pb (adjusted beta = -0.29, P = 0.003), suggesting opposing effects of Cd and Pb on hepatic CYP2A6 phenotype. In contrast, CYP2A6 activity in current smokers did not correlate with Cd or Pb, but it showed a positive correlation with serum ferritin levels (r = 0.45, P = 0.01). These finding suggest that Pb concentrations in the liver probably were too low to inhibit hepatic synthesis of heme and CYP2A6 and that the concurrent induction of hepatic CYP2A6 and ferritin was probably due to cigarette smoke constituents other than Cd and Pb.     

Disopyramide pharmacokinetics and metabolism: effect of inducers.

1. The disposition of orally administered disopyramide was studied in a population of smokers (n = 6) and non-smokers (n = 8) before and during phenobarbitone treatment (100 mg daily for 21 days; Cp 21st day = 13.9 +/- 2.0 micrograms ml-1). The comparative inducibility of these populations by phenobarbitone was assessed as was the inductive effect of cigarette smoking, per se. Furthermore, the determinants of the intensity of the inductive effect were examined, as well as the effect of the barbiturate on the binding of disopyramide to alpha 1-acid glycoprotein (AGP). 2. Smokers and non-smokers exhibited similar half-lives (6.48 +/- 1.49 vs 6.66 +/- 1.02 h), apparent total body clearances (0.100 +/- 0.020 vs 0.117 +/- 0.034 l h-1 kg-1), mean renal clearances (0.043 +/- 0.0093 vs 0.057 +/- 0.013 l h-1 kg-1) and apparent intrinsic metabolic clearances (0.057 +/- 0.015 vs 0.060 +/- 0.024 l h-1 kg-1) before phenobarbitone treatment. 3. Both populations responded comparably to barbiturate exposure in that apparent intrinsic metabolic clearance more than doubled. Interestingly, the magnitude of this increase was highly dependent on the observed baseline apparent intrinsic metabolic clearance, (r' = 0.81; P less than 0.001). 4. Phenobarbitone treatment of non-smokers resulted in an increase in the AUC of the active metabolite N-despropyl disopyramide (MND), but not significantly (3.8 +/- 1.6 vs 4.1 +/- 2.3 micrograms ml-1 h). Similar results were observed in smokers (3.5 +/- 1.4 vs 3.9 +/- 2.0 micrograms ml-1 h, respectively). 5. The percent of administered dose recovered in urine as disopyramide in non-smokers was significantly decreased upon phenobarbitone treatment (43 +/- 6% vs 25 +/- 5%), whereas the percent of dose recovered as MND increased significantly in this group (25 +/- 6% vs 31 +/- 5%). The population of smokers responded similarly. 6. At doses typically used to achieve hepatic microsomal enzyme induction in man, phenobarbitone treatment caused no significant change or trend towards a change in serum AGP concentrations as measured using the radial immunodiffusion method in nonsmokers (67.4 +/- 19.9 mg dl-1 vs 68.0 +/- 40.7 mg dl-1) or smokers (64.5 +/- 15.7 vs 67.9 +/- 14.9). Similarly, when AGP concentration was estimated in serum from non-smokers using a nephelometric method no effect attributable to phenobarbitone was observed (47.9 +/- 1.3 vs 47.9 +/- 16.8 mg dl-1). Consistent with this observation, disopyramide free fraction was not affected by barbiturate treatment.     

Studies of aztreonam transfer into the fetus and amniotic fluid in early pregnancy

The materno-fetal transfer of aztreonam by a single intravenous dose of 1 g was examined in 7 volunteer women undergoing induced abortion in early pregnancy and the following results were obtained. After administration of the drug, maternal blood levels at 15, 30, 60 and 120 minutes were 77.24 +/- 6.09 micrograms/ml (Mean +/- S.E.), 37.84 +/- 5.85 micrograms/ml, 25.62 +/- 3.15 micrograms/ml and 18.10 +/- 2.22 micrograms/ml, respectively. Amniotic fluid level of the drug was low in 3 cases, of which amniotic fluid levels were determined; 0.74 microgram/ml after 229 minutes, 0.83 microgram/ml after 280 minutes and 0.74 microgram/ml after 328 minutes. Fetal tissue concentration of the drug was below our detection limit at 120 minutes. Tissue levels of villus and decidua in 6 cases were also too low to be detectable between 89 and 328 minutes after injection.     

Usefulness of salivary trans-3'-hydroxycotinine concentration and trans-3'-hydroxycotinine/cotinine ratio as biomarkers of cigarette smoke in pregnant women

Nicotine is rapidly and extensively metabolized in humans and negatively impacts the developing fetus. The concentrations of nicotine, cotinine, trans-3'-hydroxycotinine (hydroxycotinine), and norcotinine in pregnant smokers' oral fluid were evaluated to determine usefulness as biomarkers of cigarette smoking. Sixteen participants were divided into two groups: eight light smokers (LS) who smoked < or =10 cigarettes/day and eight heavy smokers (HS) who smoked > or =20 cigarettes/day. Oral fluid specimens (n=415) were collected throughout pregnancy and analyzed with solid-phase extraction followed by gas chromatography-mass spectrometry-electron impact selected ion monitoring. Median concentrations of nicotine, cotinine, and hydroxycotinine in oral fluid of LS ranged from 241.1 to 622.0, 80.6 to 387.5, and 14.4 to 117.7 ng/mL and for HS 146.5-1372.2, 66.0-245.8, and 38.3-184.4 ng/mL, respectively. Salivary cotinine and hydroxycotinine concentrations were significantly correlated in LS (r = 0.55, p < 0.01) and HS (r = 0.74, p < 0.01). Ratios of hydroxycotinine/cotinine in oral fluid from pregnant women averaged 0.30 +/- 0.18 (range, 0.07-1.05) for LS and 0.68 +/- 0.25 (range, 0.29-1.83) for HS. Based on these preliminary data, the best ratio to differentiate light from heavy pregnant smokers was 0.41. Salivary hydroxycotinine and cotinine concentrations are both good biomarkers of cigarette smoking. Determining the hydroxycotinine/cotinine ratio may differentiate light from heavy tobacco use and help predict increased fetal tobacco exposure.     

Comparison of polyfluoroalkyl compound concentrations in maternal serum and amniotic fluid: A pilot study

The extent to which polyfluoroalkyl compounds (PFCs) are detectable in amniotic fluid is unknown. Using paired samples from 28 women, we compared the concentration of 8 PFCs measured in serum, the standard matrix for assessing human exposure, amniotic fluid from routine amniocentesis, and urine. Perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorooctane sulfonate (PFOS), and perfluorohexane sulfonate (PFHxS) were detected in all maternal serum samples. The number of amniotic fluid samples with detectable concentrations differed by PFC (PFOA n=24; PFNA n=10; PFOS n=9; PFHxS n=4). The correlation coefficient between maternal serum and amniotic PFC levels varied considerably by PFC (PFOA ρ=0.64, p<0.001; PFNA ρ=0.05, p=0.9; PFOS ρ=0.76, p=0.01; PFHxS ρ=0.80, p=0.2). Using linear regression, PFOA appeared to be commonly detected in amniotic fluid if the serum concentration exceeded approximately 1.5ng/mL whereas PFOS was rarely detected in amniotic fluid until the serum concentration was about 5.5ng/mL. No PFCs were detected in urine.     

Fundamental and clinical studies on ceftazidime in the perinatal period

Fundamental and clinical studies were carried out on ceftazidime (CAZ) in the perinatal period, and the results obtained were summarized below. Following bolus intravenous injection of CAZ 2 g, maternal serum concentrations of CAZ were as high as 145.3 +/- 17.2 micrograms/ml (mean +/- S.D.) at about 10 minutes, and then gradually decreased to 46.7 micrograms/ml at 2 hours, 5.31 micrograms/ml at 5 hours and 4 minutes, and 1.54 micrograms/ml at 11 hours and 10 minutes. The CAZ was detected in umbilical cord serum immediately after the administration, and concentrations were 31.0 +/- 1.54 micrograms/ml at about 10 minutes. Although the concentrations gradually decreased thereafter, they were higher than those in maternal serum at 3 hours and later and was 3.00 micrograms/ml at 11 hours and 10 minutes. The CAZ was detected in amniotic fluid a little later than in umbilical cord serum, and concentrations of CAZ in amniotic fluid were as low as 1.50 +/- 0.67 micrograms/ml at about 10 minutes after the administration. Concentrations then gradually increased to 12.8 micrograms/ml at 2 hours and 26.5 micrograms/ml at 5 hours and 4 minutes, and even at 11 hours and 10 minutes, they were as high as 14.2 micrograms/ml. The above results demonstrated that the transfer of CAZ through placental barrier was very rapid and satisfactory. Also, CAZ showed good transfer into amniotic fluid, as well as sufficient retention, and was considered to be an effective antibiotic for prophylaxis of both fetal infections and amniotic fluid infections.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cadmium-induced nephropathy in the development of high blood pressure

In recognition of a central role of the kidney in long-term blood pressure control, we undertook an in-depth analysis of the relationship between blood pressure and kidney damage caused by environmental exposure to the common pollutants cadmium and lead. The subjects were 200 healthy Thais, 16 and 60 years of age (100 female non-smokers, 53 male non-smokers, and 47 male smokers). None of these subjects had been exposed to Cd or Pb in the workplace and their urinary Cd concentrations ranged from 0.4 to 37 nM, whereas their urinary Pb concentrations ranged from 0.1 to 30 nM. The prevalence of high blood pressure was 2%, 8% and 19%, respectively in subjects with low, average and high Cd-burden (linear trend chi2=6.4, P=0.01). Multiple regression analysis revealed a significant positive association between Cd-burden and blood pressure in male non-smokers (adjusted beta=0.31, P=0.02) and an inverse association between blood pressure and urinary Pb excretion rate in male smokers (adjusted beta=-0.38, P=0.005). Associations between Cd-burden and nephropathies were evidenced by increases in urinary excretion of beta2-microglobulin (P=0.02) and N-acetyl-beta-d-glucosaminidase (P=0.005) in subjects with high Cd-burden, compared with the subjects with average Cd-burden. In addition, an association between Cd-related nephropathy and high blood pressure was evidenced by a 20% increase in the prevalence of high blood pressure in people with NAG-uria (linear trend chi2=4.3, P=0.04). Our present study provides first evidence for a possible link between renal tubular damage and dysfunction caused by environmental Cd exposure and increased risk of high blood pressure.     

Transthyretin, thyroxine, and retinol-binding protein in human cerebrospinal fluid: effect of lead exposure.

Transthyretin (TTR), synthesized by the choroid plexus, is proposed to have a role in transport of thyroid hormones in the brain. Our previous studies in animals suggest that sequestration of lead (Pb) in the choroid plexus may lead to a marked decrease in TTR levels in the cerebrospinal fluid (CSF). The objectives of this study were to establish in humans whether TTR and thyroxine (T(4)) are correlated in the CSF, and whether CSF levels of Pb are associated with those of TTR, T(4), and/or retinol-binding protein (RBP). Eighty-two paired CSF and blood/serum samples were collected from patients undergoing clinical diagnosis of CSF chemistry. Results showed that the mean value of CSF concentrations for TTR was 3.33 +/- 1.60 microg/mg of CSF proteins (mean +/- SD, n = 82), for total T(4) (TT(4)) was 1.56 +/- 1.68 ng/mg (n = 82), for RBP was 0.34 +/- 0.19 microg/mg (n = 82), and for Pb was 0.53 +/- 0.69 microg/dl (n = 61 for those above the detection limit). Linear regression analyses revealed that CSF TTR levels were positively associated with those of CSF TT(4) (r = 0.33, p < 0.005). CSF TTR concentrations, however, were inversely associated with CSF Pb concentrations (r = -0.29, p < 0.05). There was an inverse, albeit weak, correlation between CSF TT(4) and CSF Pb concentrations (r = -0.22, p = 0.09). The concentrations of TTR, TT(4), and Pb in the CSF did not vary as the function of their levels in blood or serum, but RBP concentrations in the CSF did correlate to those of serum (r = 0.39, p < 0.0005). Unlike TTR, CSF RBP concentrations were not influenced by PB: These human data are consistent with our earlier observations in animals, which suggest that TTR is required for thyroxine transport in the CSF and that Pb exposure is likely associated with diminished TTR levels in the CSF.     

Transfer of latamoxef into human burn blister fluid and its pharmacokinetic analysis

Latamoxef (LMOX) (50 mg/kg) was administrated intravenously to burned patients over 1 hour period. Burn blister fluid and serum were taken during 8 hours after injection, and concentrations of LMOX in burn blister fluid and serum were determined by bioassay using E. coli as a test organism. The serum concentrations of LMOX were 170.8 +/- 30.6 micrograms/ml at 30 minutes, 227.0 +/- 19.8 micrograms/ml at 1 hour, 90.3 +/- 21.4 micrograms/ml at 2 hours, 52.9 +/- 14.6 micrograms/ml at 3 hours, 38.7 +/- 13.3 micrograms/ml at 4 hours, 25.1 +/- 8.1 micrograms/ml at 5 hours, 20.5 +/- 8.1 micrograms/ml at 6 hours, 13.0 +/- 5.5 micrograms/ml (mean +/- S.D., n = 5) at 8 hours after the injection. The LMOX concentrations in burn blister fluid were 36.9 +/- 32.8 micrograms/ml at 30 minutes, 77.5 +/- 42.2 micrograms/ml at 1 hour, 85.4 +/- 19.6 micrograms/ml at 2 hours, 76.4 +/- 18.5 micrograms/ml at 3 hours, 63.5 +/- 17.8 micrograms/ml at 4 hours, 54.9 +/- 17.1 micrograms/ml at 5 hours, 34.8 +/- 10.3 micrograms/ml at 6 hours, 25.2 +/- 4.8 micrograms/ml (mean +/- S.D., n = 7) at 8 hours after the injection. The data obtained were analysed pharmacokinetically. The serum levels were analysed by two-compartment model, and the LMOX levels in burn blister fluid were analysed by the model, in which blister was considered as a small part of the peripheral compartment. In results, Tmax and Cmax of LMOX levels in burn blister fluid were calculated as 1.81 hours and 90.6 micrograms/ml, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Urinary lead levels among farmers in non-polluted areas in Japan

Urine samples, 1163 in total, were collected in the winters of 1982 and 1983 from 132 male farmers and 1031 female farmers in 6 non-polluted areas in various parts of Japan. The urine samples were analyzed for lead concentration by means of flameless atomic absorption spectrophotometry after wet digestion followed by solvent extraction in the presence of sodium diethyldithiocarbamate. The lead concentration in urine (Pb-U; adjusted for a specific gravity of 1.016) distributed log-normally with a geometric mean (GM) of 1.81 micrograms/l (GSD = 1.99) for men (n = 132) and 2.08 micrograms/l (1.95) for women (n = 1031). No age-related changes in Pb-U were observed in either sex in the 30-79 year age range, and there was no sex-related difference in Pb-U. Analyses of female smokers together with area- and age-matched non-smokers suggested that the smoking habit would cause a significant increase in Pb-U. Comparison of the present findings with Pb-U levels published in the literature disclosed that the current Pb-levels among the Japanese population appear to be lower than the levels in Western Europe and the U.S.A.     

Fibrinogen, lipoprotein (a), albumin and bilirubin (F-L-A-B) levels and cardiovascular risk calculated using the Framingham equation

OBJECTIVES: To determine the correlation between cardiovascular risk calculated using the Framingham equation and the circulating levels of 4 'emerging'predictors of vascular events: fibrinogen (Fib), lipoprotein (a) (Lp(a)), albumin (Alb) and bilirubin (Bil) (F-L-A-B). PATIENTS AND METHODS: A retrospective survey was carried out using patients referred to a specialist university-based clinic. A total of 376 patients with primary dyslipidaemia (209 men), without overt vascular disease, had their cardiovascular risk estimated using the Framingham equation. RESULTS: Among the men, smokers (n=45) were significantly younger (p =0.014) than non-smokers (n=164). Smokers when compared with non-smokers had significantly higher median Fib levels (3.84 (1.15-5.87) vs. 3.08 (1.44-5.47) g/l; p<0.0001) and lower median Bil levels (8 (3-17) vs. 10 (1-28) micromol/l; p=0.016). When non-smoker men without clinically evident vascular disease were considered, there was a significant positive Fib and negative Alb correlation with calculated risk, whether the family history was considered or not. Moreover in smokers, the only significant correlation was a negative one between Bil and cardiovascular disease risk. Lp(a) correlated with risk for stroke in women non-smokers whether the family history was considered or not, while Alb correlated with risk for stroke in women non-smokers without family history. CONCLUSION: Fib, Lp(a), Alb and Bil (F-L-A-B) may be predictors of vascular events in high-risk populations. Prospective studies should evaluate whether the F-L-A-B markers are useful in the assessment of cardiovascular risk load. Such an advantage would make treatment more cost effective by improving patient targeting. The F-L-A-B markers could eventually become targets for new drugs.     

The diffusion of cefazedone into heart muscle, prostatic and skin tissue and into bile

The diffusion of cefazedone into human heart muscle, prostatic and skin tissue as well as bile fluid was investigated. 40 to 80 min after a single injection of 100 mg/kg (n = 14) the concentration in the heart muscle was between 10.8 and 85.5 micrograms/g. The respective serum levels were between 117 and 168.1 micrograms/ml. The single i.v. injection of 2 g cefazedone resulted within 30 min in a mean concentration of 34.63 +/- 9.75 micrograms/g in the prostatic tissue and in serum levels of 139.07 +/- 39.68 micrograms/ml (n = 14). In 5 patients additional values were estimated after 60 min. At this time the antibiotic concentrations were 24.92 +/- 1.31 micrograms/g in the tissue, with simultaneous serum levels of 87.25 +/- 20.86 micrograms/ml. 1 h after a 500 mg i.v. dose, concentrations in bile taken from T-tube were between 71.4 and 210 micrograms/ml. After 2 h there was a mean level of 83.2 micrograms/ml which was significantly above the serum concentrations at the same time (1 h = 35.25 +/- 7.17; and 2 h = 20.5 micrograms/ml). The bile concentration of 2 patients taken 5 h after cefazedone injection was 4.95 and 11.6 micrograms/ml. The cefazedone concentrations in the skin were estimated mainly in biopsies from granulating leg ulcer tissues. The mean concentrations in 4 cases were 120 +/- 28.7 micrograms/g 3 h after i.v. injection of 2 g cefazedone. The simultaneous serum levels were between 14.85 and 68.2 micrograms/ml, in one patient with extreme venous stasis the tissue concentration was only 8.1 micrograms/g. Cefazedone should be regarded as an antibiotic with excellent penetration into tissues.     

A sensitive cadmium-affinity assay for the determination of thionein in urine

A sensitive cadmium-affinity assay was developed for measurement of urinary thionein (Th) level. Acidification with HCl (2.5 M) was used to remove metal ions from purified urinary metallothionein (MTh), adsorbed on activated polystyrene tubes. It was found that the amount of 109Cd bound to standard Th (rabbit Th) was proportional to that of Th in the concentration range of 20-6000 ng/ml. The method exhibited a sensitivity below 20 ng/ml and a precision of about 5%. The results of the Cd-affinity assay were unaffected by dilution of, or addition of standard Th to urine samples. Under the latter circumstances, the Cd-affinity assay was performed with a mean analytical recovery of 100.3 +/- 4%. Addition of Cd, Zn, Hg and Cu (50 micrograms each) or glutathione and cysteine (0.1 mmol) to urine specimens (1 ml) did not interfere with the determination of Th. The mean values of urinary Th in healthy subjects were 200 +/- 53 micrograms/g creatinine (n = 9) and 256 +/- 97 micrograms/g creatinine (n = 8) for men and women respectively. The mean daily excretions of Th by non-fasting female and male healthy adult rats were 9.95 +/- 2.7 micrograms (n = 10) and 18.2 +/- 3.9 micrograms, respectively. The Cd-affinity assay succeeded in indicating Cd exposure and/or development of Cd toxicity in rats.     

Human developmental exposure to endocrine active compounds

Quantification of exposure to environmental contaminants such as endocrine active chemicals (EACs) during critical periods of development, particularly in utero, remains largely unexplored. Therefore, we tested the hypothesis that EACs can be detected and quantified in second trimester human amniotic fluid. Amniotic fluid was obtained from women (n=175) undergoing routine amniocentesis between 14 and 21 weeks gestation. Samples were assayed by gas chromatography/mass spectrometry (GC/MS) for common organochlorine contaminants and dietary phytoestrogens. The DDT metabolite p,p'-DDE was found in approximately 25% of amniotic fluid samples (mean±S.D., 0.15±0.06 ng/ml) whereas the dietary phytoestrogens, genistein and or daidzein were found in 96.2% of samples tested (0.94±0.91 and 1.08±0.91 ng/ml, respectively). Our results demonstrate that: (1) human amniotic fluid is a suitable biological medium to evaluate developmental exposure to EACs, and (2) fetuses are exposed to biologically active levels of EACs in mid pregnancy.     

Calcium supplementation during lactation blunts erythrocyte lead levels and delta-aminolevulinic acid dehydratase zinc-reactivation in women non-exposed to lead and with marginal calcium intakes

The purpose of this study was to evaluate the effect of calcium supplementation during lactation on changes in blood lead indices from late pregnancy to early lactation in women with low calcium intakes and low lead-exposure. Forty-seven women, non-occupationally exposed to lead and with habitually low calcium intake ( approximately 600 mg/d), participated in the study from 29 to 38 weeks of pregnancy to 7-8 weeks post-partum, non-supplemented (n=25) and supplemented (n=22) with calcium (500 mg/d) during 6 weeks after delivery. Erythrocyte lead (PbRBC) and in vitro reactivation with zinc of blood delta-aminolevulinic acid dehydratase (Zn-delta-ALAD% reactivation) were used as lead indices. In the non-supplemented group, PbRBC and Zn-delta-ALAD% reactivation increased significantly (P<0.001) from pregnancy (0.202+/-0.049 microg Pb/g protein and 18.3+/-6.0%) to lactation (0.272+/-0.070 microg Pb/g protein and 22.7+/-6.2%). No significant changes of these indices were observed in the calcium-supplemented group from pregnancy (0.203+/-0.080 microg Pb/g protein and 15.8+/-4.5%) to lactation (0.214+/-0.066 microg Pb/g protein and 16.3+/-4.1%). PbRBC levels and Zn-delta-ALAD% reactivation at lactation were lower (P<0.05) and hematocrit levels were higher (P<0.05) in the calcium-supplemented compared to the non-supplemented women. Calcium supplementation during lactation appears to blunt the lactation-induced increase in maternal blood lead and its inhibitory effect on delta-ALAD and possibly on maternal erythropoiesis.     

Oral nifedipine pharmacokinetics in pregnancy-induced hypertension.

The pharmacokinetics of oral nifedipine were studied in 15 women with pregnancy-induced hypertension in the third trimester of pregnancy to determine if the drug's disposition was different from that in nonpregnant patients. Peak serum concentrations of 38.6 +/- 18 ng/ml occurred at approximately 40 minutes after ingestion of nifedipine 10 mg. The terminal elimination half-life (mean 1.3 +/- 0.5 hrs) was shorter than that reported for normotensive volunteers and nonpregnant hypertensives after oral dosing. Mean +/- SD apparent elimination clearance of 2.0 +/- 0.8 L/hr/kg was more rapid than that in healthy volunteers (mean 0.49 +/- 0.09 L/hr/kg). Random serum concentrations were progressively higher in patients receiving larger daily doses. Nifedipine was detected in samples of fetal cord blood and amniotic fluid at concentrations approximately 93% and 53% those of simultaneous maternal vein samples, respectively. The findings indicate that nifedipine may achieve greater antihypertensive efficacy in pregnant women if administered at shorter intervals.     

No background concentrations of di(2-ethylhexyl) phthalate and mono(2-ethylhexyl) phthalate in blood of rats

We measured the background levels of di(2-ethylhexyl) phthalate (DEHP) and its hydrolytic metabolite mono(2-ethylhexyl) phthalate (MEHP) in blood from naive female Sprague-Dawley rats and in de-ionized charcoal-purified water using an analytical procedure that is based on sample treatment with acetonitrile, n-hexane extraction and analysis by gas chromatography. In blood, blank values of 91.3 +/- 34.7 micrograms DEHP/l (n = 31) and 30.1 +/- 13.1 micrograms MEHP/l (n = 20) were obtained, and in water, values of 91.6 +/- 44.2 micrograms DEHP/l (n = 26) and 26.7 +/- 10.4 micrograms MEHP/l (n = 15) were found. Since there is no difference between the background valves obtained from blood of naive rats and water, we conclude that DEHP and MEHP result from contamination during the analytical procedure.     

Analysis of cefepime tissue penetration into human appendix.

Cefepime is a new extended-spectrum cephalosporin with gram-positive and gram-negative coverage including Staphylococcus aureus and Pseudomonas aeruginosa. We evaluated the drug's plasma, peritoneal fluid, and appendix tissue concentrations in patients with a postoperative diagnosis of perforated or gangrenous appendicitis. Patients 18 years of age or older were randomly assigned to receive either cefepime 2 g every 12 hours plus metronidazole 500 mg every 6 hours intravenously, or gentamicin 1.5 mg/kg plus clindamycin 900 mg every 8 hours intravenously. During surgery, appendix tissue, plasma, and peritoneal fluid samples were obtained, and frozen at -70 degrees C for high-pressure liquid chromatographic analysis. Thirty-five patients with perforated (26) or gangrenous (9) appendicitis had concentrations acceptable for analysis. The mean time between the administration of cefepime and the time of sampling (referred to as delta time) was 5.99 +/- 3.75 hours (mean +/- SD). The values for plasma (n = 34), tissue (n = 33), and peritoneal fluid (n = 25) concentrations were 16.27 +/- 21.87 micrograms/ml, 4.84 +/- 6.15 micrograms/g, and 14.4 +/- 22.84 micrograms/ml, respectively. The appendix tissue:plasma ratio was 0.66 +/- 0.52 and the peritoneal fluid:plasma ratio was 0.66 +/- 0.51. Spearman rank correlations indicated statistically significant correlations between plasma concentration (r = -0.889; p less than 0.0001), peritoneal fluid concentration (r = -0.783; p = 0.0002), and appendix tissue concentration (r = -0.704; p = 0.0016) versus delta time.(ABSTRACT TRUNCATED AT 250 WORDS)