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Biomedical subjects

F Moll

Publications and source records attributed to F Moll.

At least 37 records · Page 2Linked to original sources
PubMed1996

[Current strategies in patients with urinary diversion, 2: Upper urinary tract].

Improved surgical methods and changed management of invasive bladder cancer lead to an increased number of patients with urostomies. The number of patients with internal stents is increasing, too. Numerous surgical options are currently available for both male and female patients. Lifestyle implications are as important as the selection of the adequate diversion such as ileal conduit, continent cutaneous diversions or orthotopic bladder replacement.

Catheters, Indwelling↗
PubMed1995

Pharmacodynamics of a liposomal preparation for local anaesthesia.

A phospholipid containing formulation with tetracaine (CAS 94-24-6) for topical anaesthesia was developed. In vitro drug liberation as well as in vivo efficacy and duration of the anaesthetic effect were investigated. The in vitro liberation constant was 0-.626 +/- 0.005 mg/(cm2.square root of h for a liposomal gel formulation containing 2% (m/l) tetracaine. The gel showed high efficacy in anaesthetizing the skin after topical application. After 60 min of application complete anaesthesia of the skin was observed with all volunteers. The duration of anaesthesia after removing the application system was 150 min on average. The determination of the in vivo penetration rate resulted in values between 0.010 and 0.015 mumol/min.cm2 tetracaine.

Administration, Topical↗
PubMed1994

Starburst dendrimers: enhanced performance and flexibility for immunoassays.

Starburst dendrimers are novel, water-soluble polymeric materials, with a well-defined composition and structure. In our application, we used dendrimers composed of poly(amidoamine) groups to which we coupled several specific antibodies, to investigate potential formats based on radial partition immunoassay. The coupled antibodies have retained their stability and immunological binding after coupling, both in solution and when immobilized onto a solid support. On the basis of our feasibility studies with model systems, we conclude that immunoassays can be developed with performance equivalent to or better than that in many established systems. By application of a mixture of the dendrimer-coupled antibody and the analyte of interest to the solid phase, we have investigated the performance characteristics of solution-phase immunoassays. Our experiments demonstrate enhanced sensitivity for creatine kinase MB isoenzyme (CKMB), thyrotropin, and myoglobin assays and reduced instrumental analysis time for the CKMB assay.

Creatine Kinase↗
PubMed1990

Optimizing and characterizing alignment of oriented lipid bilayers containing gramicidin D.

31P NMR spectroscopy and optical microscopy have been used to characterize samples of gramicidin D in oriented lipid bilayers. Correlations have been made between the defect structures observed under crossed polarizers by optical microscopy and characteristic features of 31P NMR spectra. The sample preparation protocol has been improved using these techniques to achieve minimal dispersion of the bilayer normal and minimal amounts of unoriented sample. The molar ratio of gramicidin to dimyristoyl-phosphatidylcholine, the extent of hydration, and the cosolubilizing solvent system were used as the protocol variables. While hydration level and solvent system had profound effects on the sample orientation the molar ratio did not. However, the 31P chemical shift anisotropy is very sensitive to the molar ratio and can be used as an in situ method for determining the molar ratio.

Dimyristoylphosphatidylcholine↗
PubMed1988

Solvent history dependence of gramicidin A conformations in hydrated lipid bilayers.

Reconstituted lipid bilayers of dimyristoylphosphatidylcholine (DMPC) and gramicidin A' have been prepared by cosolubilizing gramicidin and DMPC in one of three organic solvent systems followed by vacuum drying and hydration. The conformational state of gramicidin as characterized by 23Na NMR, circular dichroism, and solid state 15N NMR is dependent upon the cosolubilizing solvent system. In particular, two conformational states are described; a state in which Na+ has minimal interactions with the polypeptide, referred to as a nonchannel state, and a state in which Na+ interacts very strongly with the polypeptide, referred to as the channel state. Both of these conformations are intimately associated with the hydrophobic core of the lipid bilayer. Furthermore, both of these states are stable in the bilayer at neutral pH and at a temperature above the bilayer phase transition temperature. These results with gramicidin suggest that the conformation of membrane proteins may be dictated by the conformation before membrane insertion and may be dependent upon the mechanism by which the insertion is accomplished.

Circular Dichroism↗
PubMed1987

Solid-state 15N NMR of oriented lipid bilayer bound gramicidin A'.

Highly oriented samples of lipid and gramicidin A' (8:1 molar ratio) have been prepared with the samples extensively hydrated (approximately 70% water v/w). These preparations have been shown to be completely in a bilayer phase with a transition temperature of 28 degrees C, and evidence is presented indicating that the gramicidin is in the channel conformation. An estimate of the disorder in the alignment of the bilayers parallel with the glass plates used to align the bilayers can be made from the asymmetry of the nuclear magnetic resonances (NMR). Such an analysis indicates a maximal range of disorder of +/- 3 degrees. Uniformly 15N-labeled gramicidin has been biosynthesized by Bacillus brevis grown in a media containing 15N-labeled Escherichia coli cells as the only nitrogen source. When prepared with labeled gramicidin, the oriented samples result in high-resolution 15N NMR spectra showing 12 resonances for the 20 nitrogen sites of the polypeptide. The frequency of the three major multiple resonance peaks has been interpreted to yield the approximate orientation of the N-H bonds in the peptide linkages with respect to the magnetic field. These bond orientations are only partially consistent with the extant structural models of gramicidin.

Calorimetry, Differential Scanning↗
PubMed1987

Somatosensory evoked potentials in the assessment of thoracic outlet compression syndrome.

To evaluate the assessment of thoracic outlet compression syndrome (TOS) by objective methods, we prospectively studied a group of 80 consecutive patients with disabling TOS who had been selected for surgical therapy. Comprehensive pre- and postoperative neurophysiologic tests were used and included electromyography, nerve conduction times, F wave determination, and somatosensory evoked potentials (SEPs) of median and ulnar nerves in neutral and stressed positions. Measurements were made of Erb's point peak (N9), cervical peak (P/N13), and cortical complex (N18-P22). Amplitude ratios were calculated for each side, and interpeak latencies were measured for N9-P/N13, P/N13-N18, and N9-N18. SEP results were abnormal on the affected side in 59 of 80 patients (74%); ulnar peak amplitudes were either less than 33% of median, reduced by more than 50% in the stressed position, or reduced by more than 50% when compared with the contralateral side. Of 64 patients studied pre- and postoperatively with SEP, 40 of 47 abnormal tests showed improvement, with 30 of these returning to normal values in the early postoperative period. Excellent clinical correlation was evident in 43 of these 47 patients (92%) who had pre- and postoperative tests; with relief of symptoms reflected in improved SEP, or continued symptoms explained by evidence of persistent or residual nerve dysfunction. The present methodology and criteria for test interpretation demonstrate that SEP can document the neurocompressive component of TOS and provide an objective assessment of pre- and postoperative clinical observations.

Action Potentials↗
PubMed1986

The anterior scalene muscle in thoracic outlet compression syndrome. Histochemical and morphometric studies.

Histochemical studies and morphometric fiber type analysis were done on biopsy specimens of anterior scalene muscle (ASM) from patients with thoracic outlet compression syndrome (TOS), without structural abnormality. Hypertrophy and atrophy factors were determined from muscle fiber histograms of ASM from controls, patients with TOS, and after scalene tenotomy. Scalene muscle from patients with TOS showed marked type 1 (tonic contracting) fiber predominance (85.1% +/- 5.1%) and type 1 fiber hypertrophy (55.6 +/- 2.7 microns). After tenotomy there is a reduction of type 1 fiber representation, selective atrophy in the type 1 fiber system (atrophy factor, 0.66 +/- 0.24), and increase of type 2 fibers. These distinctive changes indicate that ASM is uniquely structured in fiber composition to sustain prolonged contraction. The ASM in patients with TOS demonstrates an extraordinary adaptive transformation and recruitment response in the type 1 fiber system reflecting chronic increased tone or motor neuron stimulation. These observations form a basis for clarifying the structural and pathophysiologic changes in TOS.

Adult↗