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Biomedical subjects

G A Nagel

Publications and source records attributed to G A Nagel.

At least 19 recordsLinked to original sources
PubMed1998

Tumor Biology Center Freiburg, Germany. From molecular biology to supportive care.

Tumor Biology Center Freiburg is the only private cancer research center in Germany. There are two hospitals, one each for cancer rehabilitation and medical oncology, and also two institutes focusing on cancer research. Anticancer drug development is the major research goal of the Center. Scientific evaluation of unconventional therapies in cancer is a special part of the drug development program. Within this context the supportive care program of the Center has a specific focus on nutrition, pain treatment, and counseling.

Cancer Care Facilities↗
PubMed1995

[Unconventional therapeutic procedures in oncology].

The popularity and acceptability of unconventional therapy in cancer are increasing. Generally patients ask for unconventional therapy not as a substitute for standard tumor therapy but as a complementary means of improving their health. Discriminating against unconventional therapies on principle might cause patients to seek the advice of unqualified healers. In the search for ways of including particular unconventional therapies into standard therapeutic regimens, possible therapeutic goals and therapeutic substances are defined. For the destruction of cancer cells there is no alternative to standard therapy. On the other hand, conventional medicine has little else to offer if therapeutic goals are followed within the concept of health promotion. The importance of the concept of health promotion in cancer therapy is discussed.

Adjuvants, Immunologic↗
PubMed1993

[Naturopathy as metaphor].

Scientific medicine criticises alternative, natural medical trends as being non-scientific, using untested means and being noncontributive to medical progress. As much to the point these arguments might be, as much they are defensive, since this criticism might extend to some questionable developments in scientific medicine. The term of natural medicine then stands also for the search for confidence and security, for the credence in natural self-healing and the wish of the ill for autonomy. Natural medicine also questions the rationale for the new directions in modern medicine. The actual movement of natural medicine is no longer the personification of an unconsidered, fundamentalistic rebellion from earlier times against the establishment of rational and technical science. It has integrated a constructive spiritual wisdom from modern ecology and expresses the concern that inner values, the moral and spiritual growth, do not keep pace with the apparent progress of feasible modern medicine. In this context a non-prejudiced and open discussion of these critical positions in our society could give an important role to the Academy of Lucerne 1991.

Attitude of Health Personnel↗
PubMed1992

[Ethics versus ethos: current ethical problems in palliative oncology].

Difficult moral concerns and choices are a characteristic of palliative cancer medicine. Problems in patient information, palliative chemotherapy, treatment with unconventional remedies and clinical drug development are given as examples. The physician-scientist as member of a clinical cancer research institution particularly faces ethically troublesome situations. It is argued that next to the acquisition of bioethical competence by 'doing' staff, members working in scientific and medical frontiers should specifically be trained to identify, analyse and resolve ethical dilemmas. In conclusion, a biomedical ethics programme is presented which will be instituted at a new cancer center, comprising the establishment of a humanities research group, ethical liaison, consultation and information services as well as a system of inhouse bioethical quality control.

Bioethics↗
PubMed1992

Steady-state and dynamic properties of cardiac sodium-calcium exchange. Sodium-dependent inactivation.

Sodium-calcium exchange current was isolated in inside-out patches excised from guinea pig ventricular cells using the giant patch method. The outward exchange current decayed exponentially upon activation by cytoplasmic sodium (sodium-dependent inactivation). The kinetics and mechanism of the inactivation were studied. (a) The rate of inactivation and the peak current amplitude were both strongly temperature dependent (Q10 = 2.2). (b) An increase in cytoplasmic pH from 6.8 to 7.8 attenuated the current decay and shifted the apparent dissociation constant (Kd) of cytoplasmic calcium for secondary activation of the exchange current from 9.6 microM to < 0.3 microM. (c) The amplitude of exchange current decreased synchronously over the membrane potential range from -120 to 60 mV during the inactivation, indicating that voltage dependence of the exchanger did not change during the inactivation process. The voltage dependence of exchange current also did not change during secondary modulation by cytoplasmic calcium and activation by chymotrypsin. (d) In the presence of 150 mM extracellular sodium and 2 mM extracellular calcium, outward exchange current decayed similarly upon application of cytoplasmic sodium. Upon removal of cytoplasmic sodium in the presence of 2-5 microM cytoplasmic free calcium, the inward exchange current developed in two phases, a fast phase within the time course of solution changes, and a slow phase (tau approximately 4 s) indicative of recovery from sodium-dependent inactivation. (e) Under zero-trans conditions, the inward current was fully activated within solution switch times upon application of cytoplasmic calcium and did not decay. (f) The slow recovery phase of inward current upon removal of cytoplasmic sodium was also present under the zero-trans condition. (g) Sodium-dependent inactivation shows little or no dependence on membrane potential in guinea pig myocyte sarcolemma. (h) Sodium-dependent inactivation of outward current is attenuated in rate and extent as extracellular calcium is decreased. (i) Kinetics of the sodium-dependent inactivation and its dependence on major experimental variables are well described by a simple two-state inactivation model assuming one fully active and one fully inactive exchanger state, whereby the transition to the inactive state takes place from a fully sodium-loaded exchanger conformation with cytoplasmic orientation of binding sites (E1.3Ni).

Adenosine Triphosphate↗
PubMed1991

[Physician and patient between science and natural treatment--from the oncologist's viewpoint].

This contribution is a plea for an understanding between scientific oncology and one promoting healing by natural methods. The center of this dispute is not the therapist using natural medicine nor his doing but the needs of the cancer patient for which scientific medicine does not provide. An analysis of weak points in clinical oncology based on the multifarious critique of its academic achievements has not been attempted yet in a systematic fashion. Such a self critique is needed however for all the trusting people and for proper credibility. Such an empirical and even incomplete approach to this discussion demonstrates that our proper deficits as well as the expectations of a cancer patient can be defined. They rest mainly in the area of emotional non rational behaviour. Modern psycho-oncology should permit to modify the traditional limits of science-based actions in oncology such that more patients feel sheltered in a scientific therapy program. It is improbable for natural methods to fade away, and probably this might not be desirable since they are traditionally instrumental for a critical scientific dialogue.

Attitude to Health↗
PubMed1991

Double-blind randomised trial of the antiemetic efficacy and safety of ondansetron and metoclopramide in advanced breast cancer patients treated with epirubicin and cyclophosphamide.

Ondansetron was compared with metoclopramide for antiemetic efficacy in a randomised double-blind trial in 122 patients with advanced breast cancer. All patients were treated with epirubicin (greater than 50 mg/m2) and cyclophosphamide (greater than 500 mg/m2). 50 patients receiving ondansetron and 60 with metoclopramide were considered evaluable. Ondansetron was at least as effective as metoclopramide in the control of vomiting and nausea. The percentage of patients with complete plus major control was 72% (59-85%) vs. 61% (48-74%) on day 1 (P = 0.230) and 79% (67-91%) vs. 66% (53-78%) on days 2-3 after chemotherapy (P = 0.122). Over the 3-day study period, nausea was absent or mild in 60% of the patients treated with ondansetron, compared to 45% given metoclopramide (P = 0.064). No major drug-related side-effects were reported. 1 patient receiving ondansetron experienced gastrointestinal disturbance and headache. Episodes of diarrhoea, fever, hyperkinetic syndrome, fatigue, restlessness and migraine with vomiting were reported by 5 patients treated with metoclopramide. None of the changes in the biochemical or haematological parameters was attributed to the antiemetic treatments.

Adult↗
PubMed1990

[Decreased plasma zinc levels in metastatic breast cancer].

Zinc is an essential component of many metalloenzymes for DNA and proteinsynthesis including RNA and DNA polymerases. It has been shown by several investigators that zinc is accumulated in breast cancer tissues. To investigate a possible relation between plasma zinc levels and tumor load, plasma zinc levels were evaluated in 76 patients with non metastatic breast cancer (no evidence for disease after mastectomy) and in 66 patients with metastatic breast cancer. Zinc concentrations were measured in plasma using an atomic absorption spectrophotometer (normal range 80-150 mcg/dl). In patients with metastatic disease plasma zinc concentrations were in the lower region of the normal range or depressed (arithmetic mean: 84.9 SD 21.6 mcg/dl), whereas patients with non metastatic breast cancer had normal zinc levels (arithmetic mean: 126.0 SD 27.7 mcg/dl). The difference between the two groups was highly significant (p = 0.001, t = -9.742, 140 degrees of freedom). It is concluded, that plasma zinc in breast cancer patients is depressed according to the stage of the disease. Based on experimental data a substitution of zinc cannot be recommended.

Biomarkers, Tumor↗
PubMed1990

[Mucin-like carcinoma-associated antigen: sensitivity and specificity in metastatic breast cancer].

The clinical usefulness of a tumor marker essentially depends on its sensitivity and specificity for a certain tumor. To prove, wheather the new tumor marker 'mucin-like carcinoma-associated antigen' could be used for the management of breast cancer patients, we determined its serum concentration in 50 healthy blood donors, 130 patients with various non-malignant diseases, 138 patients with different metastazised tumors and 137 breast cancer patients. 78 of the breast cancer patients had known metastases while 59 had no evidence of disease after initial surgical and adjuvant therapy. Only 2% of the blood donors and 3% of the patients with non-malignant diseases exceeded the cut-off level of 15 U/ml. In contrast to these findings, 28% of patients with various metastazised tumors and 77% of patients with metastazised breast cancer had serum levels above 15 U/ml. Breast cancer patients without evidence of disease had elevated marker values in only 3%. In breast cancer the serum levels of this antigen depends on the type of metastases. Maximal concentrations were found in mixed metastases while cutaneous or lymph-node metastases showed the lowest rate of positivity. Furthermore a good correlation of serial determined marker levels with the course of the disease was observed, so that we conclude, that mucin-like carcinoma-associated antigen can be used in follow-up of patients with metastazised breast cancer. Because of its high sensitivity and specificity it provides some advantage over other markers used in this disease.

Antigens, Neoplasm↗
PubMed1990

High-dose epirubicin in combination with cyclophosphamide (HD-EC) in advanced breast cancer: final results of a dose finding study and phase II trial.

In the dose finding study we were able to demonstrate that an increase of the epirubicin dose to 120 mg/m2 in combination with cyclophosphamide (600 mg/m2) is possible. The phase II trial had to check the efficacy and the toxicity of this combination with a therapy interval of 21 days. 34 patients with metastatic breast cancer previously not treated with chemotherapy for metastatic disease entered this phase II trial, which tested the efficacy and toxicity of the chemotherapy combination epirubicin 120 mg/m2 and cyclophosphamide 600 mg/m2 (HD-EC regimen) i.v. every three weeks. Excluded from the trial were patients at risk of anthracycline toxicity and those with bone or brain metastases. Results compare favourably with best data reported in the literature for chemotherapy of metastatic breast cancer: overall remission rates of 73% (35% CR, 38% PR), median TTP of 58 weeks for CR (range 32-168 weeks) and 52 weeks for the PR group (range 24-110 weeks); median survival time for CR 71+ weeks (range 52-196+), for PR 74+ weeks (range 40-134+ weeks). No therapy was given for remission maintenance after a stable remission was obtained. This results in a very favourable ratio of time with chemotherapy to maintenance time without chemotherapy, which is 10 weeks/62 weeks for CR and 12 weeks/49 weeks for PR. Evidence of tumor remission was found in 80% of the patients who already responded to chemotherapy after the first cycle. The early onset of tumor response as well as the short induction chemotherapy period necessary to obtain best response are considered major advantages of the HD-EC regimen.

Adult↗