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Biomedical subjects

H D Wehner

Publications and source records attributed to H D Wehner.

31 records · Page 2Linked to original sources

[Elimination properties of the congener n-propanol].

Intravenous injections of n-propanol (25 mg, 50 mg, 100 mg, 200 mg, 300 mg) provoke blood concentration curves having exponential shapes of dose dependent rate constants after a sufficiently long time (2 min). They have to be seen therefore as a result of a non-linear elimination process controlled by a Michaelis-Menten-kinetic. Using the Lineweaver-Burk-method the characteristic data of metabolism are determined, namely the maximal velocity of metabolizing beta PrOHmax as 2.5 mg/l min and the Michaelis-Menten-constant as 10 mg/l. An increase of the ethanol exposition causes a prolongation of the mean residence time of n-propanol in the body. This phenomenon is to be interpreted as the result of an inhibition of the n-propanol metabolism by ethanol. The inhibition constant KPrOHEtOH concerned with this process is determined experimentally and has a value of 0.1%.

1-Propanol↗

[Acute polyneuritis in non-A, non-B hepatitis].

Neurologic involvement may occur in the course of acute viral hepatitis; acute polyneuritis is an extremely infrequent manifestation. Hepatic failure, leading to death on the 10th day of disease, became manifest in a 26-year-old man on the 6th day of postinfectious polyneuritis Guillain-Barré-Strohl requiring ventilation. Clinical aspects, additional diagnostic assessment and post mortem findings supported diagnosis of nonA-non-B hepatitis. A causal connection between both disease entities appears likely.

Acidosis↗

[Ethanol clearance in the integrated tissue space].

Interchange of ethanol between the compartments of the body results from transport in a linked convection-diffusion system. This system can be described mathematically by dividing up the cardiac output in a shunt flow and a flow immediately mixed into the integrated solvent volume of the body. Experimental measurement shows that the ratio of shunt flow and mixing flow is nearly 1:1. Furthermore, this division allows a calculation of the arterial ethanol concentration from the venous one and an estimation of the quantity of ethanol diffused into the tissue volume.

Animals↗

Compound action potentials in the peripheral nerve induced by shock-waves.

Projectiles hitting the human body cause shock waves spreading throughout the tissue. To verify a presumed interaction between these shockwaves and nervous tissue electrophysiological experiments have been performed showing the following results: 1. Compound action potentials (CAPs) are provoked in the peripheral nerves by the shockwaves. 2. The amplitude of the CAPs correspond to the magnitude of the shockwaves. 3. There is no electrical activity in the peripheral nerves below a certain threshold pressure. 4. "Saturation effect" is occurring beyond a certain pressure limit.

Action Potentials↗

Shockwave-induced compound action potentials in the peripheral nerve.

To verify a presumed interaction between shockwaves arisen by impacts of high velocity projectiles and nervous tissue an electrophysiological experiment is performed with the following results: In peripheral nerves regular compound action potentials (CAPs) are provoked by shockwaves the amplitudes of which are increased corresponding to the pressure intensity of the shockwaves. The nerve shows no electrical activity below a certain pressure threshold (0.75 bar). Saturation of the CAP amplitude occurs beyond a pressure limit of 8 bar.

Animals↗

The action of beta-adrenoceptor antagonist penbutolol on the pacemaker current of cardiac Purkinje fibres.

The action of beta-adrenoceptor antagonist penbutolol on the current underlying pacemaker activity in cardiac Purkinje fibres was analysed using the voltage clamp technique described by DECK et al. (1964). After the application of adrenalin, beta-blockers are able to counteract the well known shift of the s-kinetics of the pacemaker current. However, without any prior application of adrenalin the beta-blocker Penbutolol has no effect on these kinetics except for a small depression of the amplitude of the pacemaker current tails. The rectifier properties of the pacemaker current and the negative slope of the fully activated current voltage relationship of iK2 are unchanged. Penbutolol is able--even after a longer period of washout (about 60-90 min was necessary)--to protect the beta-adrenoceptors from the action of adrenalin (HASHIMOTO et al., 1979). These findings suggest that beta-blockers are competitive inhibitors of beta-stimulators and further support the notion that the pacemaker current in cardiac Purkinje fibres is controlled by beta-adrenoceptors.

Animals↗

[Gunshot reconstructions based on individually parametrical 3-dimensional victim models].

In cases of lethal firearm injuries computer enhanced anatomical feasibility studies can provide unambiguous clues concerning self-versus extraneous infliction. To this end individualized digital 3-dimensional geometrical models of the victim and the weapon are generated true to scale with the help of the CAD software (POSER Version 4, egi.sys AG). All anatomical data relevant to the motion apparatus and the range of movement as well as the injuries of the individual victim are carefully documented and serve as input parameters for the digital geometrical model. The bullet path is visualized as a cylinder between entrance and exit wound. A series of simulation sequences then can be carried out by the variation of anatomically possible shot positions and the virtual grasp of the weapon. An exact alignment of the firearm's barrel and the bullet path is a reliable statement for the feasibility of self-infliction. In addition to circumstantial evidence the digital reconstruction of the firearm shot admits of unambiguous conclusions about the course of the traumatic event.

Adult↗

[Immunohistochemical insulin evidence at the injection site].

Under suspicion on an injection of high doses of insulin with suicidal or homicidal intention, the local detection of a vital injection of insulin is necessary for the critical examination. The submitted immunohistochemical method shows, that: the insulin-specific positive immunoreaction of the subcutaneous fatty tissue is assigned to an injection of insulin, although a missing staining does not exclude a premortal application of insulin, a widened immunopositive intercellular space between the subcutaneous lipocytes as expression of a local edema points to the intravitality of the injection of insulin.

Adipose Tissue↗