Characterization and identification of na-cl sources in ground water.

Elevated concentrations of sodium (Na+) and chloride (Cl-) in surface and ground water are common in the United States and other countries, and can serve as indicators of, or may constitute, a water quality problem. We have characterized the most prevalent natural and anthropogenic sources of Na+ and Cl- in ground water, primarily in Illinois, and explored techniques that could be used to identify their source. We considered seven potential sources that included agricultural chemicals, septic effluent, animal waste, municipal landfill leachate, sea water, basin brines, and road deicers. The halides Cl-, bromide (Br), and iodide (I) were useful indicators of the sources of Na+-Cl- contamination. Iodide enrichment (relative to Cl-) was greatest in precipitation, followed by uncontaminated soil water and ground water, and landfill leachate. The mass ratios of the halides among themselves, with total nitrogen (N), and with Na+ provided diagnostic methods for graphically distinguishing among sources of Na+ and Cl- in contaminated water. Cl/Br ratios relative to Cl- revealed a clear, although overlapping, separation of sample groups. Samples of landfill leachate and ground water known to be contaminated by leachate were enriched in I and Br; this provided an excellent fingerprint for identifying leachate contamination. In addition, total N, when plotted against Cl/Br ratios, successfully separated water contaminated by road salt from water contaminated by other sources.

Plasma concentrations of isosorbide dinitrate after cutaneous and sublingual doses to human subjects.

After application of 100 mg (nominal dose) isosorbide dinitrate as an ointment to the skin of human subjects, mean drug concentrations were 1 to 2 ng/ml for 1.5 hour and reached a peak of 6.2 ng/ml at 6 hours. Thereafter, mean concentrations declined slowly to 2.9 ng/ml at 12 hours and 1.2 ng/ml at 24 hours. After a sublingual dose of 5 mg isosorbide dinitrate, mean drug concentrations reached a peak of 15.9 ng/ml at 0.5 hour and declined with a half-life of about 50 minutes. The mean bioavailability of isosorbide dinitrate from the ointment was estimated as 30 per cent of that from the sublingual tablet when corrected for differences in dose/body weight ratio. The results demonstrate that concentrations of isosorbide dinitrate in plasma can be maintained for relatively long periods when the drug is applied to the skin.

Sleep-endocrine profile of the antidepressant mianserin.

The effects of mianserin, a tetracyclic antidepressant, on sleep stages and on the nocturnal secretion of cortisol, ACTH, growth hormone, prolactin and tryptophan were studied on 11 normal male volunteers in a double-blind, placebo-controlled study. Mianserin increased Stage 3 time (p less than 0.001) and Stage 4 time (p less than 0.01). It reduced the number of REM periods (p less than 0.001), the REM latency after sleep onset (p less than 0.01) and both the total and percentage REM time (p less than 0.05). A reduction in both the total sleep time (p less than 0.05) and the percentage of total time in bed (p less than 0.05) were the only significantly carry-over effects from the drug treatment period. No significant difference in any biochemical measurement was found between placebo and drug treatment.

Pituitary thyroid function and prolactin release following intravenous administration of TRH and pyroglutamyl-histidyl-prolyl-ß alanine amide to healthy volunteers.

The synthetic oligopeptide pyroglutamyl-histidyl-prolyl-ß-alanine amide, structurally related to thyrotrophin releasing hormone (TRH), has been investigated in healthy male volunteers for its effect on pituitary thyroid function and on serum prolactin levels. In an open randomised 2-way crossover study the peptide has been compared with TRH on an equal dose basis following intravenous administration at 4 dose levels. The synthetic material had significantly lower thyrotrophin (TSH)-releasing activity than TRH while the prolactin releasing potencies of the 2 peptides were about equal.

Restoration of fertility in prolactin induced premature menopause : A report of an eight year case study.

A case of infertility associated initially with amenorrhoea only and then with amenorrhoea and galactorrhoea following a successfully induced pregnancy is reported. In a period of eight years of continuous investigation and treatment this subject's infertility first responded to sequential clomiphene and human chorionic gonadotrophin (HCG) therapy resulting in a normal pregnancy. Subsequently she became refractory to this therapy. The availability of specific prolactin assays and a prolactin inhibitor (2-Br-α-ergocryptine, bromocriptine Sandoz) identified the aetiology of her amenorrhoea/galactorrhoea/infertility and provided a new mode of therapy. Planned conception has been achieved on three occasions, producing two normal males and a normal female child.

Compton suppression method and epithermal NAA in the determination of nutrients and heavy metals in Nigerian food and beverages.

We used in this study Compton suppression method and epithermal neutron activation analysis to determine the concentration of nutrients and heavy metals in Nigerian food and beverages. The work was performed at the University of Texas TRIGA Reactor by short, medium, and long irradiation protocols, using thermal flux of 1.4x10(12)n cm(-2)s(-1) and epithermal flux of 1.4x10(11)n cm(-2)s(-1). Application of Compton suppression method has reduced interferences from Compton scattered photons thereby allowing easy evaluation of Na, Cl, Ca, Cu, Mn, Mg, Co, Cr, Rb, Fe, and Se. The epithermal NAA method has enabled determination of Cd, As, Ba, Sr, Br, I, and V with little turn-around time. Quality Control and Quality Assurance of the method was tested by analyzing four Standard Reference Materials (non-fat powdered milk, apple leaves, citrus leaves, and peach leaves) obtained from National Institute for Standards and Technology. Our results show that sorghum, millet, and maize have high values of Zn, Mn, Fe, low values of Cd, As, and Se. Powdered milks, rice, beans, and soybeans were found to have moderate amounts of all the elements. Tobacco recorded high content of Cd, Mn, and As, whereas tea, tsobo leaves, Baobab leaves, and okro seed have more As values than others. However, biscuits, macaroni, spaghetti, and noodles show lower concentrations of all the elements. The distribution of these nutrients and heavy metals in these food and beverages shows the need to fortify biscuits and pastas with micro and macro-nutrients and reduce the use of tobacco, tea, tsobo leaves, Baobab leaves, and Okro seed to avoid intake of heavy elements.

Plasma concentrations of isosorbide dinitrate after administration of increasing doses of a sustained-release formulation to human subjects.

Plasma concentrations of isosorbide dinitrate have been measured after administration of increasing doses in the range 20--100 mg as sustained-release tablets (Isoket retard) containing 20 mg to human subjects. Means of peak concentrations of 4.2 ng/ml, 13.1 ng/ml, 20.7 ng/ml, 36.8 ng/ml, and 34.9 ng/ml were measured after doses of 20 mg, 40 mg, 60 mg, 80 mg and 100 mg, respectively. In the plasma of individual subjects, peak concentrations of isosorbide dinitrate increased in proportion to the dose administered. Areas under the plasma isosorbide dinitrate concentration-time curves also increased in proportion to the dose administered. Bioavailability parameters were better correlated to the dose over the range 20--60 mg than over the range 20--100 mg.

Plasma concentrations and pharmacokinetics of dihydralazine after single oral doses to human subjects.

After single oral doses of 20 mg of a suspension of dihydralazine sulphate to human subjects, the peak of mean plasma concentrations of dihydralazine of 47.0 ng ml-1 +/- 11.0 standard deviation (S.D.) (n = 7) was reached at 1 h. Mean concentrations declined biphasically with apparent half-lives of 0.57 and 4.96 h respectively. Dihydralazine was partly converted to hydralazine. The peak of mean plasma concentrations of the latter drug of 3.9 ng ml-1 +/- 1.7 S.D. (n = 7) occurred at 1-2 h after dosing with dihydralazine sulphate and declined to 1.5 ng ml-1 +/- 1.5 S.D. at 6 h. Of the seven subjects studied, three were classified as fast and four as slow acetylators. Mean clearances appeared to be slightly more rapid in fast acetylators (1.63 l min-1 +/- 0.32 S.D.) when compared to slow acetylators (1.31 l min-1 +/- 0.31 S.D.) but this difference and differences in plasma concentrations and in areas under the plasma drug concentration-time curves were not significant (p > 0.1).

Prolactin responsiveness to repeated decremental doses of sulpiride.

The variation in the prolactin response to sulpiride was studied in six normal men by repeating the same dose of the drug (50 mg) after 24 hours and on three subsequent occasions, repeating this 2 day test at an interval of 6 days with progressively halved doses of sulpiride. A similar PRL response occurred on the first day of each test period and the peak response was highly significant (P less than 0.001), occurring within 30 minutes. A gross blunting of the PRL response on the second day of each period was noted throughout the study. The difference in delta PRL between the first and second day of each period was highly significant (P less than 0.001). The delta PRL increment on the second day was inversely proportional to the dose of sulpiride; the differences in delta PRL between periods 1 and 3 and periods 1 and 4 being highly significant (P less than 0.001). This study suggests that a much lower dose of sulpiride than that normally used is adequate to stimulate PRL secretion and that care must be taken in the timing of repeat testing.