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Biomedical subjects

R Rahn

Publications and source records attributed to R Rahn.

At least 55 records · Page 3Linked to original sources
PubMed1983

Diameters of abdominal veins and arteries during nitrate therapy.

The effects of 1.6 mg NTG on the diameter of abdominal veins and arteries were investigated by means of ultrasound tomography in 26 and 28 healthy persons respectively. Fourteen patients served as controls in the venous studies and 28 in the arterial measurements. The diameter of the caval vein decreased in anterior-posterior direction within 5 minutes after nitroglycerin administration by about 22% from 14.2 +/- 4.0 mm to 11.1 +/- 3.3 mm (p less than 0.005). In contrast, the portal vein enlarged by about 27% from 10.3 +/- 1.8 mm to 13.1 +/- 2.3 mm, the superior mesenteric vein by about 12% from 8.2 +/- 1.6 to 9.2 +/- 1.4 mm, and the splenic vein by about 23% from 6.6 +/- 2.3 mm to 8.1 +/- 1.8 mm (p less than 0.001). The superior mesenteric artery and the proper hepatic artery dilated by about 12% from 7.8 +/- 0.9 mm to 8.7 +/- 0.9 mm and from 6.5 +/- 1.0 mm to 7.3 +/- 0.7 mm respectively (p less than 0.001). There was no significant change in the diameter of the abdominal aorta, however. The results show that NTG induces a relaxation of the abdominal veins and of the abdominal arteries of the muscular type. They suggest that the splanchnic veins participate essentially in the therapeutically important venous pooling effect of NTG. The reduced peripheral venous return is made sonographically visible by a collapse of the inferior vena cava. Furthermore, the influence on the windkessel function after administration of NTG seems to be mediated not by the aorta itself, but rather by its large muscular-type branches like the mesenteric and hepatic arteries.

Abdomen↗
PubMed1982

[Comparative studies with mesoptometer and nyktometer ].

Mesoptometer Model I (Oculus) and Nyktometer (Rodenstock) were compared monocularly in 328 eyes. The individual measurements varied widely, more so for mesopic vision with dazzle than for mesopic vision without dazzle. When the results were classified in accordance with the normal limits proposed by the German Ophthalmological Society there was good correlation between the two instruments. The results fell into the same category in about 85% of the cases.

Adult↗
PubMedDate not supplied

The effect of age on pharmacokinetics of the local anesthetic drug articaine.

BACKGROUND AND OBJECTIVES: With increasing age, there are physiologic changes that could affect pharmacokinetics of drugs. More elderly patients are undergoing routine dental procedures for which local anesthesia could be required. The goal of the present study was to evaluate the effect of age on pharmacokinetics of the local anesthetic agent articaine. METHODS: The submucosal infiltration anesthesia from two different dosages of 4% articaine without epinephrine was compared in healthy elderly and young volunteers. High performance liquid chromatography has been used to determine concentrations of articaine in serum. Basic pharmacokinetic parameters were calculated according to standard procedures using a two-exponent equation. RESULTS: The clearance and volume of distribution (Vdss) of articaine after infiltration anesthesia were significantly lower in elderly volunteers compared with young volunteers. The area under the serum concentration-time curve and maximum drug concentration (Cmax) values did not differ significantly with age; however, both parameters tended to be higher in elderly volunteers. No changes in terminal half-life and time to reach maximum serum concentration (t(max)) were observed. The Cmax and tmax values of the metabolite articainic acid were similar in young and elderly volunteers. CONCLUSIONS The results show that the metabolism of articaine is age-independent in healthy male volunteers. The smaller Vdss in the elderly results in a trend to higher serum levels after a given dose of articaine. No change of dosage of articaine in elderly patients should be necessary.

Adult↗
PubMedDate not supplied

[Simple mandibular bone cysts].

3 cases of simple bone cyst occurring in young adults are presented. Roentgenographic findings and criteria for diagnosis are explained. Rapid bony replacement of the cavity confirm the nonradical surgical intervention.

Adolescent↗