Effects of drospirenone/estradiol on steroid receptors and Bcl-2 in the postmenopausal endometrium.

OBJECTIVE: To evaluate the effect of drospirenone with 17ß-estradiol on the histology and expression of estrogen and progesterone receptors and of Bcl-2 protein, in endometrium of postmenopausal women. METHOD: Forty postmenopausal women, including controls, participated in this study evaluating oral hormone replacement treatment combining 2 mg/day of drospirenone with 1 mg/day of 17ß-estradiol administered for a 24-week period. The effect on the endometrium was assessed by histology and the apoptosis marker Bcl-2. The immunoexpression of estrogen (ER) and progesterone (PR) receptors in the endometrium was also measured. RESULTS: No increase in endometrial thickness was evident after either treatment, although endometrial histology was atrophic in most biopsies. The drospirenone/estradiol group showed higher expression of ER and PR in glandular epithelium compared to stroma, but the Bcl-2 protein was more immunoreactive in stroma than in glandular epithelium. Compared to controls, drospirenone/estradiol users showed higher immunoexpression of ER, PR and Bcl-2 in both glandular epithelium and endometrial stroma. CONCLUSION: A 24-week course of drospirenone with 17ß-estradiol resulted in low proliferation and was shown to lead to atrophic endometrium. The novel progestogen drospirenone seems to have favorable effects on the endometrium of postmenopausal women due to its pro-apoptotic action in glandular epithelium.

A multicommuted flow system for the determination of copper, chromium, iron and lead in lubricating oils with detection by flame AAS.

In this work, a flow analysis procedure for the determination of copper, chromium, iron and lead in lubricating oils using flame AAS as detection technique is described. The flow manifold was designed to implement the multicommutation approach and it comprised three 3-way solenoid valves controlled by a personal computer. The flow system presented allowed to process the oil samples to determine wear metals without any prior preparation. Aiming to assess accuracy the results were compared with those obtained by manual procedure using flame AAS. Applying the joint-confidence ellipse test, no significant difference at the 95% confidence level was observed. Other profitable features such as a sample throughput of 50 determinations per hour; relative standard deviations (n = 5) below 2% for Cu, and below 8% for Cr, Fe and Pb; and linear responses in the range 0-40ppm (w/w) (Cu, Fe) and 0-15ppm (w/w) (Cr, Pb) were also achieved.

Automatic multicommmutated flow system for diffusion studies of pharmaceuticals through artificial enteric membrane.

An automatic flow procedure with spectrophotometric detection was developed for the study of pharmaceuticals diffusion through an artificial enteric membrane. The manifold comprised two independent flow pathways, gathered by a diffusion unit with two compartments and an enteric lipophilic membrane. The pathways were automatically filled with solutions simulating digestive and plasmatic conditions by means of four solenoid valves. The diffusion of pharmaceuticals from the enteric to the plasmatic compartment was performed in closed loop pathways, and was continuously monitored by a flow cell coupled to the acceptor solution pathway. The volumes of the digestive and plasmatic solutions were 6.0 and 3.6 ml, respectively, which comprised filling unit compartment, pumping tubing and connecting flow lines. Pumping flow rates of donor and acceptor solutions were maintained at 6.0 and 2.5 ml min(-1), respectively. The proposed system was employed in diffusion studies of caffeine and aminophylline, and in the evaluation of the influence of tensioactive agents on the diffusion process. After continuous solutions circulation for 60 min, caffeine concentration in the acceptor stream was ca. 18% of its initial concentration at the digestive compartment. The system could be programmed to perform several replicates, stopping them with different degrees of diffusion without operator assistance. The data generated by the spectrophotometer was read by the microcomputer as a time function, and stored for further mathematical treatment.

Flow-injection spectrophotometric multidetermination of metallic ions with a single reagent exploiting multicommutation and multidetection.

A flow system designed by computer-controlled discrete commutation devices is proposed for the multidetermination of metallic ions with a single chromogenic reagent. Intermittent addition of masking agents and changes of the reaction pH were exploited to implement selective determination of four species. Multidetection with an optical-fiber CCD-array spectrophotometer enabled simultaneous measurements at different wavelengths for multidetermination. The proposed system was applied to the determination of iron, copper, nickel and zinc in alloys and pharmaceutical preparations, yielding results in agreement with those obtained by flame atomic absorption spectrophotometry at the 95% confidence level. The sampling rate was estimated to be 80 determinations per hour. Coefficients of variation lower than 2% (n = 20) were achieved for all species.

Multi-task flow system for potentiometric analysis: its application to the determination of vitamin B6 in pharmaceuticals.

A flow set-up based on the sequential injection analysis concept was designed, aiming at increased automation and robustness of procedures related with potentiometric detection in pharmaceutical control. In this sense, programmable set-up calibration, ion-selective electrode characterization, standard addition techniques and titration procedures could be carried out without any stock solutions conventional handling or modification on the physical structure of the flow system. Evaluation of a flow-through vitamin B6 selective electrode and its application to routine analysis of pharmaceuticals were selected as models to demonstrate the system potentialities. The system ability to generate in-line calibrating solutions was verified by comparing the results with those obtained with solutions prepared by the manual procedure. The vitamin B6 determination in pharmaceutical products was carried out and in-line performed recoveries gave values within 97.4-103.5%. The system ability to perform titrations was ascertained using the precipitation reaction of vitamin B6 with tetraphenylborate. Other profitable features such as lower reagent consumption with a low effluent generation volume were also achieved.

A flow system with a conventional spectrophotometer for the chemiluminescent determination of lactic acid in yoghurt.

A flow-based analytical procedure for lactate determination in yoghurt by chemiluminescence using a conventional UV-Vis spectrophotometer as detector is described. The radiation source was switched off. The flow cell was machined in acrylic with a 1 mm path length and a 80 mm(2) surface and was positioned 2 mm distal of the photodetector (100 mm(2) sensible area) in order to improve detection. The flow network computer-controlled comprised a set of three-way solenoid valves assembled to implement the multicommutation approach. The chemiluminescence was obtained by using the reaction of luminol with hydrogen peroxide, catalyzed by hexacyanoferrate (III) after enzymatic reaction with lactate. The lactate oxidase enzyme was immobilized on porous silica beads (glass aminopropyl, SIGMA). The signal generated by the spectrophotometer reaction was read by the microcomputer and stored as a function of time for further treatment. Immobilization condition, enzyme concentration, temperature, pH, stability of the enzymatic reactor, and flow rates were investigated. The feasibility of the system was ascertained by analyzing a set of yoghurt samples. Results were in agreement with those obtained by a conventional method (Boehringer UV-Kit), and no significant difference at 95% confidence level was observed. A linear response within 10-125 mg l(-1)l-lactate, a 1.9% standard deviation (n=10), and an analytical throughput of 55 determinations per hour were achieved.

A multicommutation-based flow system for multi-element analysis in pharmaceutical preparations.

A flow system exploiting multicommutation and multidetection is proposed for sequential determinations in pharmaceutical preparations. The feasibilities were demonstrated by the determination of zinc, iron, copper, calcium and magnesium without changing the flow set-up. The gravitational flow of the solutions was exploited for addition of different chromogenic reagents and sample aliquots, thus avoiding the use of a propulsion unit. Transient signals at different wavelengths were measured simultaneously employing a fiber-optic multichannel spectrophotometer. Coefficients of variation of 1.0, 1.5, 1.4, 2.5 and 2.0% were obtained for iron, zinc, copper, calcium and magnesium, respectively. The mean sampling rate for the five species was 60 determinations per hour. In comparison to continuous reagent addition systems, the consumption was up to 160-fold lower. Results for pharmaceutical preparations agreed with those obtained by Flame atomic absorption spectrophotometry (FAAS) at the 95% confidence level.

Nickel and zinc determination by flow-injection solid-phase spectrophotometry exploiting different sorption rates.

Flow-injection solid-phase spectrophotometry is applied for sequential determination of nickel and zinc, exploiting their different sorption rates on 1-(2-thiazolylazo)-2-naphthol (TAN) immobilized on C(18)-bonded silica. The Zn(II) sorption rate on the solid support is constant for flow rates ranging from 0.70 to 2.2 ml min(-1), but for Ni(II) the sorption rate decreases with increasing flow rate. A flow system was designed to perform sequential measurements at two different flow rates (0.85 and 1.9 ml min(-1)). The absorbance was measured at 595 nm, where both TAN-immobilized complexes showed maximum absorption. The coefficients of variation were estimated (n=10) as 1.1 and 1.7% (at 1.9 ml min(-1)) and 1.2 and 2.1% (at 0.85 ml min(-1)) for zinc and nickel, respectively. This strategy was applied to determine zinc and nickel in copper-based alloys and the results agreed with certified values at the 95% confidence level. The sample throughput was estimated as 36 h(-1).

Potentiometric determination of urea by sequential injection using Jack bean meal crude extract as a source of urease.

A sequential injection system was proposed to accomplish the potentiometric determination of urea. This procedure used an ammonium tubular selective electrode to assess ammonium concentration produced by enzymatic hydrolysis of urea from Jack bean meal (Canavalia ensiformis DC) crude extract. A gaseous diffusion device was coupled to the flow set-up allowing on-line sampling and suitable selectivity for determinations. A detection limit of 6.0x10(-4) mol urea l(-1), a relative standard deviation of 1.9% (n=10) and a sampling rate of 20 samples h(-1) were observed when 172 Sumner units (SU) of urease and 900 mul of sample were used. Results agreeing with a comparative method were obtained by the proposed procedure and the use of the crude extract solution combined with the sequential injection approach improved the performance, producing reproducible results and low costs in comparison with procedures using commercial enzymes.

An indirect method for the determination of chromium species in water samples by sequential inductively coupled plasma-atomic emission spectrometry.

Determination of Cr(VI) and Cr(III) in water samples by inductively coupled argon plasma-atomic emission spectrometry (ICP-AES) was performed indirectly employing an on-line system. For this purpose a column with copper shavings was used to reduce Cr(VI) to Cr(III) in acidic media, generating Cu(II) ions in the flow path. This process permitted the evaluation of concentrations in the range of 1-50 mg/l. The protocol allowed a throughput of 100 samples per hour with 10% precision in the concentration.

Sulphate preconcentration by anion exchange resin in flow injection and its turbidimetric determination in water.

A preconcentration procedure was established for sulphate determination in rain waters at the mg/l level, employing a small column packed with the AG1-X8 (200-400 mesh) anionic resin inserted into a flow injection system. Sulphate determination was performed by using the turbidimetric method based on reaction with barium. For concentrations within 0.10 and 2.0 MgSO(2-)(4)/l, a throughput of 50 determinations/hr was achieved, and the relative standard deviation of results was better than 2%.