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Biomedical subjects

W Rieck

Publications and source records attributed to W Rieck.

At least 19 recordsLinked to original sources
PubMed2000

Determination of cefditoren (ME 1206) in the plasma of elderly patients with multiple diseases using high-performance liquid chromatography.

In the present study we developed a new sensitive and selective HPLC-assay for the determination of cefditoren (ME 1206) in the plasma. The column switching technique was used to regenerate the pre-column and the analytical column separately. This method is suitable for pharmacokinetic studies and for drug monitoring. Thus, we measured plasma samples of 15 elderly patients (age range: 67-88 years), receiving cefditoren-pivoxil therapy because of infections of the respiratory tract. In addition, these patients were treated with several co-medications because of further diseases. With our HPLC-method no interfering peaks could be detected at the retention time of cefditoren (10.67 min) or of the internal standard (16.62 min). The lowest plasma concentration of cefditoren to be quantified was 25 ng/ml (R.S.D.= 15.5%, n = 5).

Aged↗
PubMed1992

High-performance liquid chromatographic method for the determination of alprazolam in plasma using the column-switching technique.

A reversed-phase high-performance liquid chromatographic method is described for the quantitative determination of alprazolam in the plasma of geriatric patients in the presence of 4-hydroxyalprazolam, alpha-hydroxyalprazolam, bromazepam, oxazepam, lorazepam, clobazam, desmethylclobazam, diazepam and desmethyldiazepam. The procedure is based on the enrichment of alprazolam on a PRP-1 pre-column, followed by the transfer of the compound in a forflush mode to the analytical column. Alprazolam can be quantified reliably down to a minimum concentration of 1 ng/ml of plasma.

Aged↗
PubMed1990

[Not Available].

Explore the source record for details and available documents.

Denmark↗
PubMed1989

Pharmacokinetics of tiaprofenic acid in geriatric patients with ischemic heart disease.

The serum levels of tiaprofenic acid were determined by HPLC in 20 geriatric patients with ischemic heart disease, and the pharmacokinetic parameters were calculated. The results indicate that in geriatric patients the drug does not accumulate when given at a dose of 300 mg twice a day. Sufficient plasma levels are reached and the short terminal phase half-life prevents accumulation. The electrolyte balance was examined during the 7 days of treatment, and no change in sodium and potassium levels in the serum or in urine were observed. Weight as well as blood pressure of the patients remained constant, so that an increased development of edema, especially with regard to the existing ischemic heart disease of the patients, could be excluded. The results of our study indicate that tiaprofenic acid at the employed dosage is suitable for the therapy of arthritis in geriatric patients suffering from ischemic heart disease, without accumulation of the drug or the development of edema.

Aged↗
PubMed1988

High-performance liquid chromatographic method for the determination of alpha-amanitin and phalloidin in human plasma using the column-switching technique and its application in suspected cases of poisoning by the green species of amanita mushroom (Amanita phalloides).

A reversed-phase high-performance liquid chromatographic assay has been developed for the simultaneous determination of alpha-amanitin and phalloidin in human plasma. The procedure is based on the enrichment of the toxins on a pre-column, followed by the transfer of both compounds in a foreflush mode to the analytical column. alpha-Amanitin and phalloidin can be quantified reliably down to a minimum concentration of 10 ng/ml in plasma (relative standard deviation less than 10%). An alternative method is recommended for hepatic coma patients.

Agaricales↗
PubMed1986

Plasma lipids and composition of red cells in four cases of Werner's syndrome.

Four cases of accelerated aging, known as Werner's syndrome (WS), are presented. Plasma lipid and lipoprotein findings and lipid compositions of red cell membranes are compared to those of old and young healthy people. Typical clinical findings, as reported in the literature, confirmed the diagnosis. Furthermore, an elevated osmotic fragility of red blood cells (RBC) was observed. RBC membranes of WS patients showed phospholipid concentrations similar to those found in people aged over 70 years, which have been reported to be lower than those of mature donors aged below 30 years. Fatty acid patterns of RBC membranes and plasma phospholipids were indicative of some disturbance in phospholipid subclass distributions in WS-patients.

Adult↗
PubMed1985

The effect of age on clinical pharmacokinetics of piracetam.

In this study the pharmacokinetics of 2-oxopyrrolidine-1-acetamide (piracetam, Nootrop), were studied in 10 geriatric patients with multiple diseases aged between 69 and 87 years. After intravenous administration of 6 g piracetam, the concentration of the drug in plasma was measured after 5, 10, 15 and 30 min as well as after 1, 2, 4, 6, 8, 10, 12 and 24 h. An analysis of laboratory diagnostic findings was carried out in parallel. The kinetic parameters were correlated with the laboratory diagnostic data and discussed together with the currently available results in the literature. The finding which seems to be of particular significance is that multimorbidity is a more important factor influencing the pharmacokinetics than age.

Adult↗
PubMed1984

Determination of 3,7-dimethyl-1-(5-oxohexyl)-xanthine (pentoxifylline) and its 3,7-dimethyl-1-(5-hydroxyhexyl)-xanthine metabolite in the plasma of patients with multiple diseases using high-performance liquid chromatography.

Pharmacokinetic studies of pentoxifylline in elderly patients with multiple diseases are described. Because of the low plasma levels of pentoxifylline and its hydroxy metabolite a new high-performance liquid chromatographic method was established. Under our chromatographic conditions, piracetam, a nootropic drug, can be easily separated from simultaneously applied pentoxifylline and its metabolite. Piracetam shows no appreciable ultraviolet absorption above 230 nm and cannot be detected at 268 nm.

Chromatography, High Pressure Liquid↗
PubMed1976

[Evaluation of orthodontic cases by means of key-punch cards. 3. Data from follow-up examinations].

484 orthodontic patients were subjected to follow-up examination. The kind of treatment, the evaluation and the factors that are of importance to continuing successes and recurrences, respectively, are described. It is pointed out that the present communication and the two previous ones aim at illustrating that the orthodontic practitioner is able to document and evaluate his cases easily with the aid of key-word cards.

Activator Appliances↗
PubMed1975

[Interpretation of orthodontically treated by means of punched cards. 2. Data at the completion of treatment].

The authors analysed the key-word cards of 3245 terminated orthodontic cases. Statistical data were obtained about treatment results, therapeutical aids, duration of treatment and co-operation of the patients. These data give a survey on the achievements of the orthodontic practitioner, the choice of his methods and the utilization of his therapeutical aids. The authors could draw certain conclusions as to their own work in practice. Furthermore, they realized that the use of key-word cards permits to evaluate critically their achievements and to perform collective scientific studies.

Dental Records↗
PubMedDate not supplied

Age-dependent measurements of amino acids in human hairs - a longitudinal study.

The amino acid composition of 148 hair samples from three sisters, covering an age-range of 13-238 months, were analysed using high performance liquid chromatography (RP-HPLC). The measured amino acid concentrations of the three donors showed different individual variation with age. The most pronounced alterations were observed in the concentrations of serine witch occurred at the age of 12-14 years. This effect can be explained by the influence of hormonal factors during puberty.

Journal Article↗
PubMedDate not supplied

Pharmacokinetics of alprazolam in elderly patients with multiple diseases.

The pharmacokinetics of alprazolam (1 mg p.o.) were investigated (using a new developed HPLC-assay) in 10 multimorbid elderly patients (five female, five male; mean age 72.8 +/- 8.2 years, creatinine clearance 63.6 +/- 25.9 ml/min, weight 68.9 +/- 13.9 kg). Compared with young and elderly volunteers from other studies peak plasma concentrations of alprazolam were decreased while peak time and elimination half-life were increased. 'Second peak' plasma levels (correlated with age and creatinine clearance) occurred in eight of 10 elderly patients. The variability associated with the pharmacokinetic parameters in the multimorbid elderly patients was far greater than that observed in young and old healthy volunteers. Mean alprazolam concentrations in multimorbid patients aged 72 years or more were elevated as compared to 'younger' patients (age range: 63-71 years). Dose reduction should be considered in the older multimorbid patients.

Journal Article↗