Determination of herbicides and a metabolite in human urine by liquid chromatography-electrospray ionization mass spectrometry

A method was developed to determine simazine, atrazine and their metabolite, 2-chloro-4,6-diamino-1,3,5-triazine, in urine. The presence of these herbicides in urine may reflect possible exposure to pesticides. Sample preparation involved protein precipitation and solid-phase extraction. The samples were analyzed by high-performance liquid chromatography-mass spectrometry. The detection limits were 0.4 mug/l and the analytes have a linear response in the interval 6-800 mug/l. The precision of the method was reflected in the RSD of <2.4% for the herbicides studied. Based on the detectable herbicide levels from spiked urine samples collected from unexposed volunteers, this method can be used to determine the low levels necessary for establishing reference values of the selected herbicides and the metabolite. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Magnesium supplementation alleviates premenstrual symptoms of fluid retention

We investigated the effect of a daily supplement of 200 mg of magnesium (as MgO) for two menstrual cycles on the severity of premenstrual symptoms in a randomized, double-blind, placebo-controlled, crossover study. A daily supplement of 200 mg of Mg (as MgO) or placebo was administered for two menstrual cycles to each volunteer, who kept a daily record of her symptoms, using a 4-point scale in a menstrual diary of 22 items. Symptoms were grouped into six categories: PMS-A (anxiety), PMS-C (craving), PMS-D (depression), PMS-H (hydration), PMS-O (other), and PMS-T (total overall symptoms). Urinary Mg output/24 hours was estimated from spot samples using the Mg/creatinine ratio. Analysis of variance for 38 women showed no effect of Mg supplementation compared with placebo in any category in the first month of supplementation. In the second month there was a greater reduction (p = 0.009) of symptoms of PMS-H (weight gain, swelling of extremities, breast tenderness, abdominal bloating) with Mg supplementation compared with placebo. Compliance to supplementation was confirmed by the greater mean estimated 24-hour urinary output of Mg (p = 0.013) during Mg supplementation (100.8 mg) compared with placebo (74.1 mg). A daily supplement of 200 mg of Mg (as MgO) reduced mild premenstrual symptoms of fluid retention in the second cycle of administration.

Fast ultrasound-assisted treatment of urine samples for chronopotentiometric stripping determination of mercury at gold film electrodes

This work describes an efficient, fast, and reliable analytical methodology for mercury determination in urine samples using stripping chronopotentiometry at gold film electrodes. The samples were sonicated in the presence of concentrated HCl and H2O2 for 15 min in order to disrupt the organic ligands and release the mercury. Thirty samples can be treated over the optimized region of the ultrasonic bath. This sample preparation was enough to allow the accurate stripping chronopotentiometric determination of mercury in the treated samples. No background currents and no passivation of the gold film electrode due to the sample matrix were verified. The samples were also analyzed by cold vapour atomic absorption spectrometry (CV-AAS) and good agreement between the results was verified. The analysis of NIST SRM 2670 (Toxic Metals in Freeze-Dried Urine) also validated the proposed electroanalytical method. Finally, this method was applied for mercury evaluation in urine of workers exposed to hospital waste incinerators. (c) 2006 Elsevier B.V. All rights reserved.

The influence of cyclosporin a on mechanical retention of dental implants previously integrated to the bone: A study in rabbits

Background: Immunosuppressive agents may induce severe changes on bone metabolism and may impair the osseointegration process during the implant healing. No data are available concerning the influence of cyclosporin A on dental implants previously integrated to the bone. The aim of this study was to evaluate the influence of cyclosporin A administration on the mechanical retention of bone previously integrated to dental implants.Methods: Eighteen female New Zealand rabbits were submitted to an implant surgery. Each animal received one commercial dental implant of 10 x 3.75 mm. After 12 weeks of an undisturbed healing period, six animals were randomly sacrificed and the removal torque test was performed (group A). In addition, six animals were submitted to a daily injection of cyclosporin A in a dosage of 10 mg/kg (group C), and six animals received saline solution as a control (group B). After 12 weeks of cyclosporin A administration, groups B and C were sacrificed and submitted to a removal torque test in which higher values can be interpreted as higher mechanical bone retention to the implant surface or higher osseointegration.Results: the removal torque results were 30.5 (+/- 9.8) Ncm for group A, 50.17 (+/- 17.5) Ncm for group B, and 26 (+/- 7.8) Ncm for group C. The statistical analysis showed significant differences between groups A and B (P < 0.05) and groups B and C (P < 0.01).Conclusion: Cyclosporin A administration may impair the mechanical retention of dental implants previously integrated to the bone.

EFFECT OF LATERAL HYPOTHALAMUS LESIONS ON THE WATER AND SALT INTAKE, AND SODIUM AND URINE EXCRETION INDUCED BY ACTIVATION OF THE MEDIAN PREOPTIC NUCLEUS IN CONSCIOUS RATS

In this-study we investigated the influence of electrolytic lesion of the lateral hypothalamus (LH) on the water and salt appetite, and the natriuretic, diuretic and cardiovascular effects induced by angiotensinergic, cholinergic and noradrenergic stimulation of the median preoptic nucleus (MnPO) in rats. Male Holtzman rats were implanted with a cannula into the MnPO. Other groups of sham- and LH-lesioned rats received a stainless steel cannula implanted into the MnPO. ANGII injection into the MnPO induced water and sodium intake, and natriuretic, diuretic, presser and tachycardic responses. Carbachol induced water intake, and natriuretic, presser and bradycardic responses, whereas noradrenaline increased urine, sodium excretion and blood pressure, and induced bradycardia. In rats submitted to LH-lesion only, water and sodium intake was reduced compared with sham rats. LH lesion also reduced the sodium ingestion induced by ANGII (12 ng) into the MnPO. In LH-lesioned rats, the dipsogenic, diuretic and presser responses induced by ANGII (12 ng), carbachol (2 nmol) and noradrenaline (20 nmol) injection into the MnPO were reduced. The same occurred with sodium excretion when carbachol (2 nmol) and noradrenaline (20 nmol) were injected into the MnPO of LH-lesioned rats, whereas ANGII(12 ng) induced an increase in sodium excretion. These data show that electrolytic lesion of the LH reduces fluid and sodium intake, and presser responses to angiotensinergic, cholinergic and noradrenergic activation of the MnPO. LH involvement with MnPO excitatory and inhibitory mechanisms related to water and sodium intake, sodium excretion and cardiovascular control is suggested.

First-void versus midstream urine culture for detection of Ureaplasma urealyticum in the urinary tract

Quantitative Ureaplasma urealyticum culture was performed on clean first-void and midstream urine to evaluate the presence of these mollicutes in the urinary tract. The results, expressed as color changing units (CCU), showed that 14 (63%) of the 22 Ureaplasma urealyticum positive patients yielded counts equal to or higher that 10(7) CCU/mL for both the initial and the middle urine specimens. No abnormal chemical or microscopic findings (protein content, leukocyte numbers) were observed. The occurrence of U. urealyticum in midstream urine samples, even when numbers are considered, may be no more than a guide to the presence of ureaplasmas in the urinary tract.

Differential pulse polarographic determination of ceftazidime in urine samples with and without prior extraction

Ceftazidime shows two main polarographic reduction peaks at pH 4.0, that at -0.45 V owing to reduction of the C=N bond in the methylethoxyimino group and that at -1.00 V owing to the reductive elimination of pyridine: the first peak is particularly suitable for the determination of ceftazidime. Ceftazidime can also be determined indirectly using the tensammetric peak at -0.60 V (in Britton-Robinson buffer pH 9.5) of pyridine liberated on hydrolysis. Ceftazidime can be determined in urine using the direct method only after Cls solid phase extraction, but it can be determined directly in the urine by hydrolysing it and using the pyridine peak. (C) 1997 Elsevier B.V. B.V.

Retention force and fatigue strength of overdenture attachment systems

This study evaluated retention force and fatigue resistance of two overdenture attachment systems. Twenty samples (O-ring and Bar-Clip) from two manufacturers (Conexao Sistemas de Protese and Lifecore Biomedical) were prepared and divided into four groups: (i) Conexao/O-ring; (ii) Conexao/Bar-Clip; (iii) Lifecore/O-ring and (iv) Lifecore/Bar-Clip, with five samples in each group. They were submitted to mechanical fatigue test using a servohydraulic machine performing 5500 cycles of insertion and removal (f=0.8 Hz), immersed in artificial saliva. Retention force values were obtained three times (0, 3000 and after 5500 cycles) simulating the clinical service, using a tensile strength at 1 mm min(-1) and load cell of 1 kN. Data were analysed with analysis of variance and Tukey's test at 5% level. Results showed that Conexao/Bar-Clip specimens had significantly higher retention values than Lifecore/Bar-Clip (44.61 and 18.44 N, respectively), Conexao/O-ring specimens had significantly lower values than Lifecore/O-ring (13.91 and 19.75 N, respectively). Conexao/Bar-Clip values were always significantly higher than those of Conexao/O-ring group (44.61 and 13.91 N, respectively). Lifecore (O-ring and Bar-Clip) presented similar values (19.75 and 18.44 N, respectively). The systems evaluated showed satisfactory retention force values, before and after fatigue testing. Conexao/Bar-Clip specimens presented the highest values. A 5-year simulation of insertion and removal did not decrease retention values or fracture components.

Retention characteristics in Bi3.25La0.75Ti3O12 thin films prepared by the polymeric precursor method

Ferroelectric Bi3.25La0.75Ti3O12 (BLT) thin films were deposited on Pt/Ti/SiO2/Si substrates by the polymeric precursor method. The films present c-axis preferred orientation after annealing at 700 degrees C for 2 h in conventional furnace. All the capacitors showed good polarization fatigue characteristics at least up to 1x10(10) bipolar pulse cycles and excellent retention properties up to 1x10(4) s. We found that the polarization loss is insignificant with five write/read voltages at a waiting time of 10 000 S. Independently of the applied electric field the retained switchable polarization approached a nearly steady-state value after a retention time of 10 s. (C) 2005 American Institute of Physics.

REDUCTION OF URINE VOLUME AMELIORATES ADRIAMYCIN-INDUCED NEPHROPATHY

1. Adriamycin, a commonly used antineoplastic antibiotic, induces glomerular lesions in rats, resulting in persistent proteinuria and glomerulosclerosis.2. The effect of urine volume on the progression of adriamycin-induced nephropathy was studied in 70 male Wistar rats (180-200 g) observed for 30 weeks and separated into 4 groups: healthy control group (HCG, N = 10) inoculated iv with 1 ml of saline, and nephrotic groups inoculated iv with a single dose of adriamycin of 3 mg/kg body weight. The nephrotic rats were separated into 3 groups (N = 20): nephrotic control group (NCG) receiving only adriamycin; dehydrated nephrotic group (DNG) water deprived for 36 h within each 48-h period, and furosemide nephrotic group (FNG) treated with 12 mg/dl furosemide, and 0.9 g/dl NaCl in the drinking water.3. The 30-week survival rates of the DNG (100%) and HCG (100%) were significantly higher than those of the NCG (85%) and FNG (55%).4. The proteinuria observed in the HCG (range, 7.38 +/- 0.7 to 13.6 +/- 1.27 mg/24 h) was significantly lower than that observed for all the nephrotic groups throughout the experiment. The DNG presented significantly less proteinuria (range, 42.71 +/- 6.83 to 140.10 +/- 19.22 mg/24 h) than the NCG (range, 35.32 +/- 7.64 to 250.00 +/- 25.91 mg/24 h) from week 10 on. There was no significant difference between the mean 24-h proteinuria of the NCG (range, 35.32 +/- 7.64 to 250.00 +/- 25.91 mg/24 h) and the FNG (range, 35.82 +/- 7.91 to 221.54 +/- 26.74).5. The mean frequency of damaged glomeruli was 0.3% +/- 0.3 for HCG, 42% +/- 6% for CNG, 40.8% +/- 8% for DNG, and 47% +/- 14% for FNG. The median value of the tubulointerstitial lesion, evaluated by a semiquantitative method, was 0 in HCG, 10 in CNG, 8.5 in DNG and 9.5 in FNG(P<0.05 for all groups compared to HCG).6. The data indicate that reduction of urine volume has a protective effect on adriamycin-induced nephropathy.

A comparative-study between visible-light-activated and autopolymerizing sealants in relation to retention

Two hundred twenty-nine first permanent molar occlusal surfaces were treated with sealants, from a group of sixty-one children. When the three sealants were analyzed at the end of the six-, twelve-, eighteen-, and twenty-four-month periods, it was observed that retentive loss was gradual. Both Concise and Delton showed superior retention when compared with Sealite.