Biomedical subjects

M Wiechmann

Publications and source records attributed to M Wiechmann.

At least 19 recordsLinked to original sources

PubMed2004

[Integrated supply models--do we need it at all?].

Much has been written about so-called Integrated Healthcare for a number of years and this healthcare model is regarded by many as the solution to our problems in the German healthcare system. Although the legal framework conditions for integrated healthcare models have existed since 2000, no operating model has yet been realised in the German statutory healthcare system (Gesetzliche Krankenversicherung, GKV). Given past experiences, the question therefore arises as to whether we need integrated healthcare models at all. The German health system provides healthcare at a very high level. It suffers nevertheless from constantly growing problems concerning decreasing quality at increasing costs. One of the reasons for this is the fact that past reforms set in the GKV did not remove structural deficits but were essentially symptom-oriented on a short-term basis. The financial relief of the past reforms therefore held only for a short time until the unresolved deficits then re-emerged as a growing problem--in terms of quality and costs. Structurally new forms of healthcare supply--so called Integrated Healthcare models--should integrate four areas: Contracts, supply, reimbursement and responsibility. The aim should be to achieve a high-quality healthcare supply at acceptable costs by appropriate selection of suitable healthcare providers and installation of efficient processes. International experience shows that a qualitatively better supply at reduced costs might be possible with Integrated Healthcare models.

Cost-Benefit Analysis↗

PubMed2004

Structural calorimetry of main transition of supported DMPC bilayers by temperature-controlled AFM.

Atomic force microscopy at high temperature resolution (DeltaT < or approximately 0.1 K) provided a quantitative structural calorimetry of the transition from the fluid (Lalpha)- to the gel (Pbeta')-phase of supported dimyristoylphosphatidylcholine bilayers. Besides a determination of the main transition temperature (T0) and the van't Hoff transition enthalpy (DeltaHvH), the structural analysis in the nm-scale at T close to T0 of the ripple phase allowed an experimental estimation of the area of cooperative units from small lipid domains. Thereby, the corresponding transition enthalpy (DeltaH) of single molecules could be determined. The lipid organization and the corresponding parameters T0 and DeltaHvH (DeltaH) were modulated by heptanol or external Ca2+ and compared with physiological findings. The size of the cooperative unit was not significantly affected by the presence of 1 mM heptanol. The observed linear relationship of DeltaHvH and T0 was discussed in terms of a change in heat capacity.

Calcium↗

PubMed2003

[Opportunities and risks of managed care].

AIM: The present paper aims at analysing and discussing managed care with its opportunities and risks. This analysis should be a further basis for a reasonable discussion concerning the implementation of managed care elements in the German Health Care system. METHOD: On the basis of an update literature research the relevant international experiences with managed care in several health care systems--especially in the United States and Switzerland--are analysed and described. Most relevant opportunities and risks of managed care are deduced from this analysis. RESULTS: The most important opportunities of managed care are the stabilisation of health care costs, an improvement of health care processes and quality and a stronger consideration of preventive measures. The possibility of choosing between several health care models and more convenient health insurance fees are opportunities for the patients. Relevant risks of managed care involve the potential withholding of medical care with the necessity of a comprehensive quality assurance and negative influences on the physicians' autonomy. Furthermore, managed care may have negative effects on the relationship between patients and physicians or between general practitioners and medical specialists. CONCLUSIONS: Managed care has proven advantages in respect of cost stabilisation and quality improvement compared with traditional health care systems. If the risks and known problems of managed care are realised and avoided, the available opportunities could be an important option to reform the German Health Care system in respect of costs and quality.

Cost Savings↗

PubMed2002

[Intrastomal refractive surgery with ultra-short laser pulses. Results from initial in vitro experiments].

PURPOSE: To investigate the possibilities and techniques for intrastromal ablation of the cornea by the use of ultra-short laser pulses. METHOD: A laser-induced plasma with a diameter of 8 mu was generated 100-300 mu below Bowmans membrane by focussing of a Ti:Saphir laser (lambda=805 nm, pulse width: 115 fs, energy: 0.6-3.3 microJ). Scanning the laser beam enabled arbitrary transsections in the corneal stroma. All experiments were performed in porcine eyes 1-4 h post-mortem. RESULTS: Two-dimensional sections were achieved applying a minimal laser energy of 0.6 microJ at a separation of the single laser effects of 10 micrometer. A 150 micrometer thick disc was excised 150 micrometer below Bowmans membrane and extracted through a keratotomy performed by the laser. Sharp-cut edges were observed by slit-lamp biomicroscopy. CONCLUSIONS: Ultra-short laser pulses are suitable for precise intrastromal ablation.

Animals↗

PubMed2001

Analysis of protein crystal growth at molecular resolution by atomic force microscopy.

High-resolution atomic force microscopy (AFM) studies have been performed to analyze the molecularity of growth steps of the (1 1 0) face of tetragonal lysozyme crystals. Besides a major population of step heights of about 5.5 nm also step heights of about half this size were observed. The latter steps always appeared pairwise. Both surfaces the 1 1 0) face and the (1 0 1) face could be imaged at molecular level. Comparison of the height pattern of the corresponding surface structure indicates that the (1 1 0) face is relatively smooth of less than 0.2 nm compared to the (1 0 1) face of about 1.5 nm. AFM linescan images of the (1 0 1) face indicate the insertion of lysozyme aggregates in solution to the crystal surface rather than lysozyme monomers. This study suggests that insertion of lysozyme aggregates in the solution yields growth steps of the (1 1 0) face of monomolecular as well as of bimolecular unit height.

Animals↗

PubMed2000

[Nutrient intake with low-fat diets in rehabilitation of patients with coronary heart disease].

We investigated the nutritional value of a very low fat diet (diet I) adapted to nutritional habits in Germany. Data were compared to a low fat diet (diet II) according to the American Heart Association. The study was performed in 37 patients with coronary heart disease (30 males and 7 females, age 45-83 yrs) stratified to the 2 dietary treatments. Daily fat intake was 38 g (24% of energy intake of 6.5 MJ/d) in diet I and 60 g (31% of 7.3 MJ/d) in diet II (p < 0.01), respectively. When compared with diet II, in diet I the intake of cholesterol, saturated and mono-unsaturated fatty acids, Vit. A, Vit. D and Vit. B12 were all reduced (p < 0.01), whereas the uptake of Vit. C was increased p < 0.01. The intake of folic acid was low in both groups. Both diets resulted in a decrease in BMI, systolic and diastolic blood pressure, plasma cholesterol and LDL cholesterol levels. Concomitantly plasma triglycerides only decreased in response to diet I but HDL cholesterol levels remained unchanged. Reduction of BMI and cholesterol levels were dependent on baseline BMI and cholesterol concentrations, respectively. The cholesterol lowering effect of diet I is in part attributed to the weight lowering effect of the diet. Taking into account the nutritional habits in Germany, very low fat diets seem to be adequate with respect to their nutritional value. Both diets are effective in lowering body weight, plasma cholesterol and triglyceride levels without affecting HDL cholesterol. These effects are most pronounced in overweight and hypercholesterolemic patients.

Aged↗

PubMed1977

[Scope and limitations of the analytical use of dansyl chloride, I: The reaction of aromatic sulfonyl chlorides with aliphatic tertiary amines: the microanalytical aspects of the Hinsberg test (author's transl)].

Contrary to the present understanding of the Hinsberg test, aliphatic tertiary amines (N,N-dimethylethylamine, bufotenin, hordenine, tropan alkaloids) are shown generally to react with aromatic sulfonyl chlorides yielding the N-substituted sulfonamide derivatives of the monodealkylated amines as the result of oxidative dealkylation of the aliphatic tertiary amines. Possible errors resulting from the indiscriminate use of either dansyl chloride, bansyl chloride or other aromatic sulfonyl chlorides for the direct analytical determination of secondary amines, secondary amino acids, noralkaloids etc., are pointed out.

Amines↗

PubMed1977

[Scope and limitation of the analytical use of dansyl chloride, II: Formation of secondary dansyl amines by the reaction of dansyl chloride with N-oxides of aliphatic tertiary amino derivatives according to the Polonovski reaction (author's transl)].

The general validity of the Polonovski reaction with sulfonyl chorides is demonstrated by the reaction of bansyl chloride and dansyl chloride with pseudotropine-N-oxide and the isomeric tropine-N-oxides yielding the corresponding N-Bansyl derivatives and N-Dansyl derivatives of the noralkalois. The consequence of this reaction for the analytical determination of secondary amino derivatives with bansyl chloride, dansyl chloride and corresponding fluorophors is that secondary amino derivatives cannot be determined in the presence of the N-oxides of these amino derivatives.

Amines↗

PubMed1976

Comparative autoradiographic and metabolic study of delta8- and delta9-tetrahydrocannabinol in the brain of the marmoset Callithrix jacchus.

The label distribution in the brain of the marmoset Callithrix jacchus following intravenous application of radioactively labeled delta8-tetrahydrocannabinol (delta8-THC) and delta9-THC is investigated by autoradiographic technique. Accumulations of label are observed in nuclei concerned with motor function, in the optic and acoustic pathways, and a few other structures. Of the two hydroxylated isomeres which were shown to be equally psychoactive the brain concentration of 11-OH-delta9-THC was found to be about 3 times higher as compared with 11-OH-delta8 THC, which may explain why delta9-THC is more potent than delta8-THC. More than 90% of the radioactivity found in the brain can be attributed to the THCs and their 11-hydroxylated isomeres. Polar metabolites are almost completely absent from the brain.

Animals↗

PubMed1975

Metabolism and autoradiographic distribution of delta-8- and delta-9-tetrahydrocannabinol in some organs of the monkey Callithrix jacchus.

Metabolism and autoradiographic distribution of the two isomeric tetrahydrocannabinols, (2,4-14-C)-delta-8-THC and (2,4-14-C)-delta-9-THC, were studied in the marmoset Callithrix jacchus. Of the two cannabinoids, delta-8-THC had a slower initial rate of biotransformation to the psychopharmacologically more potent 11-hydroxylated metabolite. This may explain the minor psychopharmacological activity of the delta-8-isomer. In glandular tissues an accumulation of unchanged delta-9-THC was observed. Autoradiography revealed characteristic label distributions in some organs 30 min after the administration of the drugs. This labelling pattern was found to be changed after a 6-hr incorporation period. The autoradiographic distribution of delta-8 and delta-9-THC appeared to be identical.

Adrenal Glands↗

PubMed1975