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Biomedical subjects

M Tewes

Publications and source records attributed to M Tewes.

10 recordsLinked to original sources
PubMed2006

Detection of Rev peptides with impedance-sensors--comparison of device-geometries.

Two different impedance-sensor geometries have been compared for the detection of Rev peptides with a molecular weight of 2.4 kDa. Planar, two-dimensional interdigitated capacitor (IDC) sensors with electrode separations of 1.1 microm as well as three-dimensional nanogap-sensors with an electrode separation of 75 nm have been used. Both sensors have been operated at a fixed frequency of 980 MHz. We discuss the specific interaction of the Rev peptide to an immobilized RNA anti-Rev aptamer (9.2 kDa) for peptide concentrations in the range of 100 nM-2 microM. For the IDC sensor, only peptide concentrations above 500 nM gave detectable signals. For the nanogap sensor, the binding process was clearly visible for all concentrations applied. The higher sensitivity of the nanogap compared to the IDC is ascribed to the improved surface-to-volume ratio.

Biosensing Techniques↗
PubMed2004

A phase I clinical and pharmacokinetic study of the camptothecin glycoconjugate, BAY 38-3441, as a daily infusion in patients with advanced solid tumors.

BACKGROUND: The aim of this study was to define the maximum tolerated dose (MTD), dose-limiting toxicity (DLT) and pharmacokinetics of the camptothecin glycoconjugate BAY 38-3441, administered as an infusion for 30 min on two separate schedules every 3 weeks. PATIENTS AND METHODS: A total of 81 patients with advanced solid tumors were treated with BAY 38-3441 either at doses of 20, 40, 67, 100, 140, 210, 315, 470 and 600 mg/m2/day for 1 day every 3 weeks (single-dose schedule), or at doses of 126, 189, 246, 320 and 416 mg/m2/day once daily for three consecutive days every 3 weeks (3-day schedule). Plasma sampling was performed to characterize the pharmacokinetics of BAY 38-3441 and camptothecin with these schedules. RESULTS: DLTs included renal toxicity, granulocytopenia and thrombocytopenia on the single-day schedule at doses > or = 470 mg/m2/day, and diarrhea and thrombocytopenia on the 3-day schedule at doses > or = 320 mg/m2/day. Other non-DLTs were gastrointestinal, dermatological and hematological. Pharmacokinetics of BAY 38-3441 and camptothecin appear to be dose-dependent, but not linear. CONCLUSIONS: Renal toxicity was dose-limiting for BAY 38-3441 using 30-min infusions on the single-dose schedule. Dose escalation to 470 mg/m2/day is feasible using a 2-h infusion. However, because of the superior safety profile, we recommend the 3-day schedule for BAY 38-3441 at a dose of 320 mg/m2/day as 30-min infusions for further phase II studies.

Camptothecin↗
PubMed2003

Capecitabine and irinotecan as first-line chemotherapy in patients with metastatic colorectal cancer: results of an extended phase I study.

BACKGROUND: To define the maximum-tolerated dose (MTD) and to evaluate the dose-limiting toxicities (DLTs) of the combination of capecitabine and irinotecan in patients with metastatic colorectal cancer. PATIENTS AND METHODS: Thirty-seven patients with measurable metastatic colorectal cancer with no prior chemotherapy for metastatic disease were treated at three dose levels (DLs). For the first two dose levels, irinotecan (70 mg/m(2)) was administered once a week for 6 weeks in combination with 2 weeks of capecitabine at 1000 mg/m(2) (DL1) or 1250 mg/m(2) (DL2) twice daily, starting on days 1 and 22. In the last dose escalation step, the dose of irinotecan was increased to 80 mg/m(2) (DL3). One cycle lasted 7 weeks. RESULTS: In the subsequent phase I trial, 96 cycles of capecitabine and irinotecan were administered. At DL3, three out of six patients experienced DLTs (diarrhea, neutropenia, asthenia). In order to confirm the safety of the recommended dose, DL2 was extended to 15 patients. Five patients (33%) showed DLTs at this dose level, which was considered too high to embark on further clinical studies. Subsequently, the starting dose (DL1) was extended to a total of 16 patients, with diarrhea being the main toxicity. The overall response rate was 38% [95% confidence interval (CI) 21% to 58%], with a median response duration of 8.7 months (95% CI 6.4-11.5 months). CONCLUSIONS: The recommended doses for further studies are irinotecan 70 mg/m(2) and capecitabine 1000 mg/m(2). The combination of capecitabine and irinotecan appears to have significant therapeutic efficacy with manageable toxicity.

Adult↗
PubMed2000

Discrepancy between patients' perspectives, staff's documentation and reflections on basic nursing care.

In recent years, Denmark has witnessed an increasing written and oral debate concerning the quality of basic nursing care. The present study is an attempt to characterize basic nursing care in a Danish hospital by collecting data on patient perceptions of their main somatic problems in seven pre-set categories. These data include documentation of patient problems in corresponding problem categories, and the staff's additional knowledge about patient problems. Triangulation of methods was used. Data were collected on 120 patients and from 22 nurses. The patients had 2.3 problems on average: pain (58%) and sleep (43%) were the problems cited most frequently. Only 31% of patients' experienced problems were documented in the nursing records. The nursing staff had more knowledge than was registered in the nursing records. However, one-third of the patients' problems was totally unknown to the nursing staff. From the patients' point of view, essential aspects of basic nursing care are overlooked in daily clinical practice. The findings show that the method employed is suitable for integration of the patients' perspective.

Cross-Sectional Studies↗
PubMed1993

[Prevention and treatment of pressure sores--a neglected research subject? An overview of clinically controlled studies in the period 1987-91].

Pressure sores are frequently seen in elderly hospitalized patients and leads to prolonged hospitalization and increased morbidity and mortality. The object of this paper was to retrieve the last five years literature regarding prevention and treatment of pressure sores. During the period 1987-1991, 751 papers on this topic were published and indexed in Medline. Only 9 of these papers represented controlled clinical trials. Three of them dealt with prevention, and the remaining 6 with treatment. Although 4 of 9 studies showed statistically significant differences between the actively treated group and the placebo group, none of the studies showed convincing clinical differences. Serious methodological flaws with respect to design, blinding, randomisation, sample size and statistical analysis were found in 8 of 9 studies. None of the clinical controlled studies on prevention of pressure sores showed any statistically significant differences between the control group and treatment with, respectively Prevasore lotion, Foam cushion and Silicore mattress. In the 6 trials on treatment of pressure sores, respectively mucopolysaccharide polysulphate creme, ketanserin creme and air-fluidized beds showed statistically better results than control treatment. We conclude that well-designed controlled clinical trials are needed to establish rational routines for prevention and treatment of pressure sores.

Clinical Nursing Research↗
PubMed1989

[Factors influencing the corrosion of amalgams].

In a comparative corrosion test specimen were produced from eleven different amalgams using two different plugging pressures and were exposed to two different corrosive solutions. As was to be expected containing amalgams corroded the most. A more accurate differentiation between the individual non gamma 2 amalgams and the two different plugging pressures was only possible with the stronger corrosive solution. Therefore this solution seemed to be better suited for a standardized corrosion test according to DIN 13904, part 2. The greater plugging pressure inhibits corrosion especially in badly corroding amalgams. This seems to be due to the limited diffusion which is the result of a smaller pore size.

Corrosion↗