Blood volume and carotid body size responses in spontaneously hypertensive rats during chronic treatment with hypobaric hypoxia or almitrine bismesylate.

The influence of chronic stimulation of the peripheral arterial chemoreceptors on plasma and red cell volumes and on carotid body volume was studied in spontaneously hypertensive rats (SHR). The animals were exposed to chronic hypobaric hypoxia or a chronic treatment with almitrine bismesylate from the 17th to the 30th week of life. At the end of the experiment the plasma volume was significantly lower in chronic hypobaric and almitrine-treated animals; the red cell volume was significantly higher in chronic hypoxic SHR only. The carotid body volume was also higher only in chronic hypoxic animals. It can be concluded that long-term stimulation of the peripheral arterial chemoreceptors influences the adjustment of the plasma volume.

[Comparative estimation of monocompartmental methods of analyzing 99m-Tc-diethylenetriamine pentaacetic acid clearance by declining plasma levels with special reference to long term studies]. / Vergleichende Wertigkeitseinschätzung monokompartimenteller Auswertverfahren der 99m-Tc-Diäthylentriaminpentaessigsäure-Clearance mit fallendem Indikator-Plasmaspiegel unter besonderer Berücksichtigung langer Untersuchungszeiten.

Plasma slope clearance estimation with 99m-Tc-DTPA corresponds to total clearance determination. When activity is measured directly in cumulative serum samples, determination of the plasma slope clearance is suitable for practical applications only if simplified analytic procedures are used. Monocompartmental analytic procedure that take the late slope of the disappearance curve into account are particularly useful for GFR estimation. The A3k3-slope-clearance analysis method is a monocompartmental procedure for determining slope clearance that is based on activity measurements between the 100th (120th) and 240th minute after injection. Compared with other monocompartmental procedures, the A3k3-clearance method shows a highly significant hyperbolic correlation with serum creatinine, a highly significant linear correlation with inulin total clearance, is age dependent and yields reproducible results. The sensitivity (frequency of correct function results in the case of disturbed glomerular function) of the A3k3-slope-clearance method with 99m-Tc-DTPA is particularly good. The practically important predictability of pathological A3k3-clearance results (frequency of correct results when the kidney function is truly reduced) is on the average 85%. The mean efficiency of the method is 88% (65-97% at the 95% confidence-level).

Chemical structure and pharmacokinetics of 99mTc-labelled aminomethane diphosphonic acid derivatives.

99mTc-labelled derivatives of aminomethane diphosphonic acid, general formula: R1R2N-CR3 [PO(OH)2]2, as well as hydroxyethane diphosphonic acid and hydroxypropane monophosphonic acid were investigated with regard to their suitability for skeleton scintigraphy. Bone accumulation was related to chemical structure. It was concluded from the experiments that compounds able to form enols are accumulated to a higher degree and that big substituents influence the affinity to bone negatively by steric hindrance.

[The diffusion constant for water in dentin in extracted healthy juvenile teeth]. / Die Diffusionskonstante für Wasser in Dentin bei extrahierten gesunden Zähnen von Jugendlichen

The authors point to the diffusion processes in dental hard tissues and describe a personal method for determining the diffusion constant in dentine. The diffusion constant in the dentine of permanent teeth from adolescents is 0.74 - 10(-2) cm2/d, measured by means of radioactively labelled water. The necessity for further studies is emphasized.

Experimental examinations on the suitability of organoaminomethane-bis-phosphonic acids for bone-scintigraphy by means of Tc-99m in animals.

Phosphororganic compounds of the general formula R2N-CH (PO(OH)2)2 were examined for their Tc-99m-labelability and suitability for bone-scintigraphy. Compared to Tc-99-m-Sn-EHDP (Hydroxyethane-1,1-diphosphonic acid), four compounds showed a better concentration in the sceleton, while three compounds remained beneath comparative values.