Fetal fibronectin in patients at increased risk for premature birth.

OBJECTIVES: The objective of this prospective study was to evaluate fetal fibronectin bedside test (Mast Diagnostica) to rule out preterm labor. STUDY DESIGN: 46 patients from between 25 and 36 weeks were included in the study over a six months period. All patients underwent only one cervical sampling at the beginning of the study. The association between the fetal fibronectine test results and various outcomes were analysed. RESULTS: 5 of the 16 women whose test results were positive had early labor and 4 of the 30 patients with negative test results had preterm delivery. The bed side test had a sensitivity of 55.6%, a specificity of 70.3%, a positive predictive value of 31.3%, and a negative predictive value of 86.7%. The addition of tocolytic therapy and intensive care resulted probably in decrease of the predictive capacity of a positive fetal fibronectine test, odds ratio 2.95 (95% confidence interval 0.54-16.85). However interval from diagnosis to delivery was shorter (P < 0.025), cervical findings (Bishop score) worse and betamimetic treatment was more frequent (P < 0.01) in the group with positive test results. CONCLUSIONS: Positive fetal fibronectine test results indicates a significant risk for the subsequent early delivery and negative test result is a good indication that subsequent preterm labor and early delivery are unlikely to occur.

The cumulation of chromium and arsenic species in fish (Poecilia reticulata).

Chromium-51 and arsenic-74 were used for the investigation of the uptake and the release of different chromium and arsenic species in fish. It has been found that only trimethylarsine can be rapidly taken up directly from water. The release of chromium(III), consumed by fish in food, is very rapid: about 99.9% of chromium is released within a few days. The same results were obtained with chromium(III) acetylacetonate or chromium(III) ethylenediaminotetraacetate. About 95% of arsenic acid, methylarsonic acid, dimethylarsinic acid or arsenic(III) diethyldithiocarbamate are released within a few days whereas the remaining arsenic is released with the biological half time 35 +/- 5 days.

The cumulation of zinc and cadmium in fish (Poecilia reticulata).

Zinc-65 and cadmium-115 m were used for the investigation of the uptake and the release of zinc and cadmium in fish. It has been found that the uptake of these elements directly from water is relatively low. Zinc and cadmium, consumed by fish in food, are released with the biological half-time 0.25 +/- 0.05 days (94%) and 65 +/- 9 days (6%) for zinc, 0.25 +/- 0.05 days (98.5%) and 36 +/- 6 days (1.5%) for cadmium. The comparison with data obtained for mercury species shows that the cumulation of these elements in fish increases in the order cadmium, zinc, inorganic mercury (II), phenylmercury and methylmercury.

The cumulation of methylmercury in fish (Poecilia reticulata).

Methylmercury labelled with mercury-203 was used for the investigation of the uptake and the release of methylmercury in fish. It has been found that methylmercury compounds adsorbed on fish food remain completely in fish and that they are released with the biological half-time of 110 +/- 20 days. The cumulation of methylmercury from water is very rapid: the cumulation constant is 237 +/- 67 days-1. Equations for the calculation of the concentration of methylmercury in fish were derived and compared with the uptake of phenylmercury and inorganic mercury.

Substoichiometric determination of heavy rare earths by isotopic dilution analysis.

A substoichiometric method for the determination of heavy rare earths (holmium, thulium) has been developed. After the addition of a substoichiometric amount of EDTA to the test sample of rare earth labelled with its radioactive isotopes, the negatively charged complex formed was separated by passage through a column of Dowex 50 x 8. Interfering metals can be removed by preliminary cupferron and diethylammonium diethyldithiocarbamate extraction. Concentrations of rare earth down to 4 x 10(-7)g 5 ml have been determined.

Substoichiometric determination of manganese by neutron-activation analysis.

A simple and rapid method for the substoichiometric determination of traces of manganese in various materials by neutron-activation analysis has been developed. After dissolution of the irradiated test sample, manganese(II) carrier is added and subsequently oxidised by peroxodisulphate to the heptavalent state. The permanganate thus formed is finally extracted into chloroform as tetraphenylarsonium permanganate using a substoichiometric amount of tetraphenylarsonium chloride. This single separation step isolates radiochemically pure manganese-56 in the analysis of a relatively simple material in which interfering elements (gold, rhenium, etc.) are absent. When this is not true, a preliminary separation of manganese from the irradiated sample, based on the extraction of manganese diethyldithio-carbamate into chloroform and followed by stripping of the manganese with dilute sulphuric acid, must be used. A simultaneously irradiated standard containing manganese must be treated in exactly the same way as a test sample. In the materials analysed by the new method 10(-5) to 10(-3)% of manganese has been determined.