Decrease of peripheral resistance after intraoperative administration of iloprost in patients with and without type 2 diabetes mellitus and with peripheral arterial occlusive disease.

BACKGROUND: In many cases, Ilomedin® infusions are applied as part of a perioperative measure in patients with peripheral arterial occlusive disease because it makes a relevant vasodilatatory effect in patients with type 2 diabetes mellitus and with/without peripheral neuropathy. AIMS: A prospective case-control study was performed to investigate the effect of prostanoids on peripheral resistance in patients with type 2 diabetes mellitus and patients without type 2 diabetes mellitus, as well as the role of peripheral neuropathy in patients undergoing arterial reconstruction. METHODS: Sixty patients undergoing arterial reconstruction were enrolled. Sufficient data were collected on 38 patients. Prior to surgery, peripheral nerve conduction velocity was measured. Blood flow volume at the common femoral artery was assessed intraoperatively using a Doppler flowmeter at four time points: at baseline before arterial reconstruction (T0), after reconstruction (T1), after 5 (T2) and 10 min (T3) after intra-arterial application of 3000 ng of Ilomedin. Peripheral resistance units were calculated as a function of mean arterial pressure and flow volume using the following formula: peripheral resistance unit = mean arterial pressure (mm Hg) / flow volume (mL/min). RESULTS: Ilomedin produced an immediate and significant drop of peripheral resistance in patients without type 2 diabetes mellitus as well as in patients with type 2 diabetes mellitus. Patients with peripheral neuropathy showed a less pronounced effect to Ilomedin compared to individuals with normal nerve conduction velocity.

Distance measurements on orthogonally spin-labeled membrane spanning WALP23 polypeptides.

EPR-based Gd(III)-nitroxide distance measurements were performed on a series of membrane-incorporated orthogonally labeled WALP23 polypeptides. The obtained distance distributions were stable upon the change of detection frequency from 10 GHz (X-band) to 35 GHz (Q-band). The α-helical pitch of WALP23 polypeptide could be experimentally observed, despite the flexibility of the two spin labels. The spectroscopic properties of Gd(III) ions and nitroxide radicals allow detecting both types of paramagnetic species selectively in different EPR experiments. In particular, this spectroscopic selectivity allows for supplementing Gd(III)-nitroxide distance measurements with independent checks of polypeptide aggregation and with measurements of the local environment of the nitroxide spin labels. All mentioned additional checks do not require preparation of further samples, as it is the case in the experiments with pairs of identical nitroxide spin labels.

Multiple Pathway Relaxation Enhancement in the System Composed of Three Paramagnetic Species: Nitroxide Radical-Ln(3+)-O2.

Longitudinal relaxation of nitroxide spin-labels has been measured for a membrane-incorporated α-helical polypeptide in the presence and absence of residual amounts of membrane-dissolved O2 and paramagnetic Dy(3+) ions. Such a model system, containing three different types of paramagnetic species, provides an important example of nonadditivity of two different relaxation channels for the nitroxide spins.

In vivo assessment of conduction velocity and refractory period of denervated muscle fibers.

Stimulation needle electromyography was used to study the muscle fiber conduction velocity and refractory period in 4 patients with long-term denervation of the lower limb muscles due to lesion of the conus cauda or cauda equina (2 untrained and 2 trained by functional electrical stimulation). In untrained patients, the results demonstrated that propagation velocity is reduced and refractory period of the muscle fiber is increased with time of denervation. The patients performing electrical stimulation training showed higher conduction velocities and reduced refractory period despite longer lasting denervation. This suggests that electrical stimulation training is effective to improve the electrical properties of the muscle fiber. Since the obtained data show a good correlation to other clinical tests and biopsy investigations, this method could serve as an additional measurement technique to specify the status of the denervated muscle. Further animal experiments and clinical studies are necessary to proof the results in comparison to more invasive established techniques.