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Biomedical subjects

G Rosenkranz

Publications and source records attributed to G Rosenkranz.

At least 19 recordsLinked to original sources
PubMed2000

Dose-finding study of valspodar (PSC 833) with daunorubicin and cytarabine to reverse multidrug resistance in elderly patients with previously untreated acute myeloid leukemia.

INTRODUCTION: This trial was designed to determine the maximum tolerated dose of intravenous daunorubicin (DNR) in combination with valspodar and to test the feasibility of P-glycoprotein modulation using valspodar in elderly patients with previously untreated acute myelogenous leukemia receiving standard induction chemotherapy. METHODS: Patients > or =60 years of age with previously untreated AML received valspodar (10 mg/kg/24 h by continuous intravenous infusion [CIV] on days 1-4 with a 2-mg/kg loading dose on day 1) in conjunction with two cycles of induction chemotherapy consisting of cytarabine (200 mg/m(2) CIV on days 1-7), and DNR (35 mg/m(2) [cohort 1] or 45 mg/m(2) [cohort 2] on days 1-3, intravenous bolus). Patients were assessed for dose-limiting toxicities (DLT), response rate, event-free and overall survival, and pharmacokinetics of valspodar and DNR. RESULTS: Valspodar was well tolerated at the lower DNR dose level (ie, 35 mg/m(2)) resulting in a 21% rate of DLT and only three toxic deaths. Treatment-related mortality was unacceptably high at the 45 mg/m(2) DNR dose level. The complete response rate was 49% overall and similar in both cohorts. The median overall survival of patients was 333 days in cohort 1 compared to 98 days in cohort 2. At baseline, 70% of assessable patients were P-glycoprotein positive. CONCLUSION: Substantial inhibition of P-glycoprotein activity can be achieved in this patient population at clinically tolerable doses of valspodar and DNR. The maximum tolerated dose of DNR was established as 35 mg/m(2). This regimen is being further evaluated in phase III trials.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Can we reduce the dose of a vaccine?

This paper describes the planning, implementation, and analysis of a clinical trial to develop a pediatric vaccine against the tick-borne encephalitis virus. The trial was primarily a dose-finding study with the following objectives: the protein content of the vaccine should be lower than that of the vaccine for adults (which was already approved) in order to reduce reactogenicity, especially the rate of fever reactions, in children. At the same time, the protein content had to be high enough so that the immunogenicity of the pediatric vaccine would be at least equivalent to that of the vaccine for adults. We discuss in detail the definition of the equivalence criterion and the considerations concerning sample size calculation. The methods described in this paper are also useful for designing clinical trials for the development of combined vaccines.

Adolescent↗
PubMed1996

Tick-borne encephalitis: development of a paediatric vaccine. A controlled, randomized, double-blind and multicentre study.

A total of 522 children between 18 months and 14 years and 191 adults between 18 and 60 years were vaccinated with TBE-vaccine according to an abbreviated schedule (0, 7, 21). The aim of the study was to investigate whether reducing the amount of antigen in the vaccination for children would preserve an adequate immune response and decrease the rate of side-effects. Efficacy was determined on the extent to which children, vaccinated with the low doses (0.4 microgram or 0.75 microgram), reacted by developing antibodies in the same way as adults treated with the approved dose of 1.5 micrograms (equivalence of titres). The titres obtained in the children with the two lower doses were equivalent to those in the adults obtained with the standard dose. Titres decreased in the children with increasing age. Children older than 12 years in the approved dosage group had the same median titres as adults. The frequency of side-effects in the two lower dose groups, especially raised temperature, was markedly reduced. Whereas 30.1% of the children vaccinated with the approved dose had raised temperature higher than 38 degrees C only 18.8% and 18.4%, respectively, of the children vaccinated with the lower doses developed such temperatures. This improved tolerance in terms of raised temperature was also reflected in the other general reactions such as tiredness, joint pain or headache.

Adult↗
PubMed1992

Effects of converting enzyme inhibitors and the calcium antagonist nifedipine alone and in combination on precontracted isolated rabbit aortic rings.

The calcium antagonist nifedipine markedly relaxed intact rabbit aortic rings precontracted with low level potassium chloride while converting enzyme (CE) inhibitors, ramiprilat, enalaprilat, and captopril were only marginally effective. Either CE inhibitor combined with nifedipine, however, significantly accentuated this relaxation. The CE inhibitors increased vascular cyclic GMP content while nifedipine was not active. Thus, inhibition of potassium chloride-induced calcium influx by nifedipine may unmask the vasorelaxant potential of CE inhibitors that in turn may result from local accumulation of endothelium-derived bradykinin.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1990

[Computed tomographic measurements of breast density].

From histogram analysis the value of computed tomography for early detection of breast carcinoma or differentiation of benign and malign processes of the breast was evaluated. The results show, that CT is not applicable and gives no improvement of diagnostics.

Breast Neoplasms↗
PubMed1990

[The reduction of radiation burden in mammography using film-screen combination systems].

The comparison of mammographic image recording systems TF-13-nonscreen film and ORTHO-MA with MIN-R screens leads to the necessary conclusion, that mammography should be carried out only with screen film combinations and an anti-scatter grid. This means improved contrast and a reduction of radiation dose to 1/3 of the dose of TF 13. Since in the GDR the film XR 10 still is used as mammographic film the fourfold of the internationally possible dose is required. The urgent change of the situation can only be achieved with respective imports.

Adult↗
PubMed1988

[The use of CT in meniscopathy].

The results of CT examination of meniscopathies in 54 patients, most of them competitive athletes, are presented. CT has an overall accuracy of about 90 per cent and can hence be used for diagnosing a lesion of the meniscus with a reasonable amount of safety, while being rapid and avoiding unnecessary exposure to stress. This method, therefore, should be a focal point of the imaging methods and thus be placed between the specialist doctor's findings and possible surgery. The pros and cons of CT compared with other imaging methods are discussed.

Athletic Injuries↗
PubMed1987

[Radiation dosage of the lens and gonads in selected CT studies].

The article is a compilation of data on the radiation exposure during the most important CT examinations. The influencing parameters are assessed and their effects are discussed. Conclusions are drawn to modify the practical approach. These results are compared with those reported in international literature.

Brain↗
PubMed1986

[Computerized tomography studies of age- and sex-related physiological variations of intracranial structures].

This paper supplies proof of the age dependence of the physiological cerebral density and ventricle size. The studies are based on the evaluation of normal cerebral computer tomograms of a total of 1100 patients of both sexes. Mathematical statistical calculations yield accurate data on the age-conditioned physiological "standard ranges" of cerebral density and ventricle width (3rd and 4th ventricle). By means of the graphic representations and calculation formulas it is possible to achieve rapid orientation provided the CT technique employed is the same. The results as communicated in this paper enable further quantification and objectivation of our CT data.

Adolescent↗
PubMed1986

[Diagnostic and therapeutic aspects of pelvic vein thrombosis in pregnancy].

Deep pelvic venous thrombosis is a severe complication during pregnancy and requires an early diagnosis and an adequate well-timed therapy. 12 pregnant women with thrombosis of deep pelvic veins have been registered ++ over a period of 10 years. Diagnosis was secured with phlebography in 5 of these cases. It is reported about the necessity and the x-ray exposure of the examination. Treatment of choice is the heparin-longtime-therapy 90 per cent of our cases have been cured successfully.

Adolescent↗
PubMed1986

[Computerized tomography studies in the assessment of radiogenic pneumopathy in an animal experiment].

An animal experimental study was conducted in 56 piglets exposed to radiation to establish new assessment criteria on radiogenic pneumopathy by employing computed tomography for diagnosis. The accurately measurable density changes in the lung parenchyma exposed to radiation appear invariably as soon as a dose-dependent threshold value is exceeded. Tolerance limits can be determined for 60Co and neutron irradiation in different fractions and single doses, the enhancement of lung density being correlated with the irradiation dose. It is not possible to establish a volume-dependent decrease in the tolerance dose. Likewise, there is no radiation-promoted co-reaction of adjacent pulmonary tissue not subjected to irradiation exposure. These results apply to the experimental animals used in the study.

Animals↗