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At least 55 records · Page 3Linked to original sources
PubMed2003

Tracking the elusive antiestrogenic effect of melatonin: a new methodological approach.

OBJECTIVES: Detection of the antiestrogenic effect of melatonin on various breast cancer cell lines and its dependence of the differential expression of estrogen receptors (ERalpha and ERbeta) and melatonin receptors (mt1 and RZRalpha). SETTING AND DESIGN: Dose-response curves of estradiol were determined in 6 different breast cancer cell lines using a colorimetric proliferation assay in the absence or presence of various melatonin concentrations. METHODS: In order to detect the minor growth inhibitory effect of melatonin, a simple yet novel approach was employed: instead of incubating cells at single estradiol-concentrations at increasing melatonin levels, breast cancer cells were grown in microwell-plates for 4 days at increasing concentrations of estradiol (10(-12)M - 10(-10)M) in the absence or presence of melatonin (10(-9)M - 10(-8)M). Cell number was determined using Alamar blue and colorimetry. RT-PCR was performed for the expression of ERalpha, ERbeta, RZRalpha and mt1. RESULTS: Melatonin at concentrations of 10(-9)M and 5 x 10(-9)M shifted the dose-response curves of estradiol to higher concentrations. Responsiveness to melatonin depended on expression of ERalpha but not on ERbeta. mRNA of ERbeta was not detectable in the breast cancer cell lines used. Only small amounts of mt1 transcripts were detectable in MCF-7 cells of one source. In MCF-7 cells transfected with the mt1 gene and in an ovarian cancer cell line mt1 was expressed at significant levels. RZRalpha was expressed in all tested cell lines at different amounts. CONCLUSION: The growth of all ERalpha-positive breast cancer cell lines can be inhibited by melatonin. The effect in most cell lines is weak yet clearly reproducible. RZRalpha clearly contributes to the growth inhibitory effect of melatonin.

Adjuvants, Immunologic↗
PubMedDate not supplied

[New methodologic approaches to solving the problem of determining the requirements for medical technology].

The authors analyze the main causes of the low standards of technical equipment of health institutions; substantiate the necessity of developing progressive standards of fitting out the treatment and prophylactic institutions with medical instrumentation and equipment; elucidate the principles of methodological approaches to the solution of the given problem; disclose the term "functional module" as the totality of the equipment with medical instrumentation of ward departments (reception rooms) of different profiles and subdivisions of the treatment and diagnostic services maintaining their work; describe the main stages of the designing of progressive equipment standards.

Equipment and Supplies↗
PubMed1988

[Classification of perinatal deaths as a function of birth weight and gestational age. New methodologic approach].

Perinatal mortality is closely related to infant birth weight. However, the examination of both gestational age and birth weight provides a more comprehensive approach. This study presents a method of evaluation which is readily applicable. Data were obtained from the computerized files of the maternity ward of the University Hospital of Caen. This report is based on case-reports of 17,952 single births, from May 1980 to July 1985 (cases of multiple birth have not been considered since their age/weight relationships are usually different). All stillborn infants and those who died within the first week of life were considered. Any infant whose gestational age was 28 weeks or more but who showed no sign of life at birth was considered stillborn. Gestational age was determined from the mother's last menstrual period, providing it concurred with the obstetrical evaluation (i.e. echographic measurements of foetus before 20 weeks of gestation). If not, the clinical evaluation was retained. Results are presented in the form of blocks, each one representing 1 week of gestational age and a birth weight of 500 g. The perinatal mortality rate was calculated for each block. Blocks of similar mortality rates (i.e. with no significant difference) were then pooled by means of a recently published method [3]. This difference between the mortality rates of 2 blocks (in percentages) may be measured by means of the chi-square test. The test enables the evaluation of the "distance" between two adjacent zones, which can be calculated for all the blocks of the graph, by pairs.(ABSTRACT TRUNCATED AT 250 WORDS)

Birth Weight↗
PubMed1995

[New methodological approaches in assessing adaptive body reactions in the system of flight medicine expertise].

The "cost" of adjustable systemic and cellular reactions in the human body in extreme environments have been assessed from the standpoint of their potentialities for upgrading special methods of evaluating and predicting functional status practiced in flight certification examination. As was stated, the functional reserves of blood circulation should be assessed by chronotropic activity of cardiac regulation in response to hypoxic exposure. The adequacy of adaptive processes on the cellular level can be drawn from the dynamics of malon-dialdehide (the by-product of lipid peroxidation) and plasma monoaminoxidase. The biochemical investigations of peripheral blood and saliva also show promise.

Adaptation, Physiological↗
PubMed1994

[New methodologic approach to the analysis of morphologic features of tuberculosis resistant to chemotherapy].

The paper considers the theoretical aspects in the morphogenesis of fibrosis in the lung parenchyma in tuberculous inflammation and the methodology of an untraditional approach whose basis is systemic analysis has been developed. The latter is a prerequisite for studying the morphogenesis of the whole infectious process. The paper discusses a number of examples showing the practical value of the described methodological approach which allows one, by using a specific histological agent, to assess how focal tuberculosis is transformed to other forms during specific therapy.

Adult↗