High-resolution distributed temperature sensing with the multiphoton-timing technique.

We report on a multiphoton-timing distributed temperature sensor (DTS) based on the concept of distributed anti-Stokes Raman thermometry. The sensor combines the advantage of very high spatial resolution (40 cm) with moderate measurement times. In 5 min it is possible to determine the temperature of as many as 4000 points along an optical fiber with an accuracy Δ T < 2 °C. The new feature of the DTS system is the combination of a fast single-photon avalanche diode with specially designed real-time signal-processing electronics. We discuss various parameters that affect the operation of analog and photon-timing DTS systems. Particular emphasis is put on the consequences of the nonideal behavior of sensor components and the corresponding correction procedures.

The antidote effect of thiosulphate and hydroxocobalamin in formation of nitroprusside intoxication of rabbits.

Sodium nitroprusside (SNP) and hydroxocobalamin (HC) - in molar ratios of 1:4, 1:5, and 1:8, respectively - were infused simultaneously during 4 h into two veins of separate ears of conscious rabbits. Controls received HC only. Sodium thiosulphate (ST) was infused with SNP at molar ratios of 1:4, 1:5, and 1:10. The observation period was 48 h. With the lowest dose of HC (1:4), SNP produced a severe metabolic acidosis; three of ten animals died during the infusion, an additional six within 24 h. When the 1:5 ratio was administered, the acidosis was less marked, but still three of seven animals succumbed within 24 h. The highest dose (1:8) prevented acidosis, however three of eight animals died. All doses of HC caused histological changes in the liver, the myocardium, and the kidney, independently if given alone or with SNP. In contrast to this, ST had a complete antidote effect, if administered in a 1:5 ratio; no acidosis was demonstrable and death did not occur. In neither dosage ST could prevent histological changes in the liver, but the kidney and the heart were not affected. In contrast to HC ST alone did not cause histological alterations. Consequently, ST is the preferable antidote and is superior to HC for preventing or treating intoxications with SNP.

Organotoxic effects of excessive doses of sodium nitroprusside in the rabbit.

The simultaneous iv. infusion in conscious rabbits of 7.5 mg/kg.h sodium nitroprusside (SNP) plus sodium thiosulfate in the molar ratios 1:5 or 1:10, respectively, for 4 h produced perilobular necroses of liver cells. 21 days after the infusion, regeneration of the damaged cells was complete. No histological changes were found in various other organs after this high dose of SNP. No signs of liver toxicity were found in rabbits that had received 0.75 mg/kg.h SNP for 8 h daily during a period of 5 consecutive days. This dose was in the range of SNP doses recommended for clinical use in human patients. Nevertheless we suggest that apart from the thiocyanate plasma levels, also the GOT, GPT, and gamma-GT concentrations in blood be controlled, especially when high doses of SNP are to be given for prolonged periods in order to exclude possible hepatotoxic effects of SNP.

Effect of sodium nitroprusside alone and in combination with sodium thiosulfate on the acid-base balance, and on thiocyanate and iron plasma levels in the rabbit.

An infusion of 7.5 mg/kg.h sodium nitroprusside (SNP) produced a fatal cyanide intoxication in conscious rabbits (n=6) after 60.8 +/- 6.7 min (chi +/- S.E.). When, however, the cyanide antidote sodium thiosulfate was infused simultaneously at a rate of 31.25 or 62.5 mg/kg.h, i.e. a molar SNP/thiosulfate ratio of 1:5 or 1:10 respectively, this high dose of SNP was well tolerated. In both concentrations, thiosulfate abolished the development of the severe metabolic acidosis that results from the infusion of toxic doses of SNP alone. In the presence of thiosulfate, the plasma level of thiocyanate rose linearly with the infusion time indicating a rapid detoxification of cyanide released in vivo from SNP, whereas at the end of the infusion of SNP alone no increase in plasma thiocyanate could be measured. No clear advantage of the higher thiosulfate dosage over the lower one could be established. The iron plasma level only rose during the first hour of SNP plus thiosulfate infusions reaching the iron binding capacity of plasma, and then remained stable throughout the experiment. This indicates that the iron plasma level is an unsuitable parameter for the control of SNP therapy. We suggest the simultaneous administration of SNP and thiosulfate at a molar ratio of 1:5 to make SNP a safer drug.

Separation and quantitative determination of acecarbromal, carbromal, and bromisoval as well as their main metabolites by means of high-pressure liquid chromatographic analysis.

A method is described to separate and quantitatively determine bromoureides and their bromo- and non-bromo-metabolites by means of high-pressure liquid chromatography. This method allows simultaneous measurement of these substances after intake of therapeutic as well as toxic doses.

Simultaneous determination of glutethimide, methyprylon, and methaqualone in serum by gas liquid chromatography.

A gas chromatographic method is described that permits the simultaneous determination of glutethimide, methyprylon, and methaqualone in serum samples. The threshold of sensitivity for each of the three hypnotics is 0.2 mg/1.

[Studies on the metabolism and distribution of 14C-sodium nitroprusside in rats (author's transl)]. / Untersuchungen über den Stoffwechsel und die Organverteilung von 14C-markiertem Natriumnitroprussid an Ratten

Studies on the in vivo degradation of 14C-labelled nitroprusside (NP) were conducted in rats and indicated that the primary product was cyanide and not thiocyanate. With the administration of higher doses of sodium nitroprusside (NNP; Nipruss) cyanide, thipcyanate, Fe++ and Fe+++ were evident in the blood plasma, whereas [Fe(CN)6]4- and [Fe(CN)6]3- were not detected. The biological half-life for the disappearance of nitroprusside was about 2 min with a dose of 0.4 mg NNP/kg and was 28 min with a dose of 6.25 mg NNP/kg. Nitroprusside and its degradation products, cyanide and thiocyanate, were eliminated mainly in the urine. Significant accumulation of nitroprusside did not occur either in blood vessel walls, in smooth muscles, or in parenchymal organs.