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Biomedical subjects

A Nielsen

Publications and source records attributed to A Nielsen.

At least 73 records · Page 4Linked to original sources
PubMed1985

Characterization of the T61 human breast carcinoma established in nude mice.

This paper gives a biological characterization of the T61 human breast carcinoma established in nude mice. The human origin of the tumour was verified by the demonstration of the presence of human chromosomes exclusively in the tumour cells. The tumour cells were found by chromosome analysis and flow cytometric DNA analysis to be aneuploid. By electron microscopy, the tumour cells were shown to display the characteristics of glandular epithelium; a light microscopic examination revealed morphological characteristics similar to those of an axillary metastasis of the patient from whom the T61 tumour was derived. Furthermore, the tumour was shown to contain classical receptors for oestrogen and progesterone. The growth of the tumour was characterized by gompertzian growth curves. Since the T61 tumour has a response pattern to endocrine treatment which differs from that described for other human breast tumours grown in nude mice, this tumour may provide a valuable supplement in the study of human breast cancer and endocrine treatment.

Animals↗
PubMed1985

Quantitative influence of serum creatine kinase isoenzyme MB estimated infarct size and other prognostic variables on one year mortality after acute myocardial infarction.

The aim of the present study was to determine the strength of the relation between serum creatine kinase isoenzyme MB estimated infarct size, other prognostic variables, and mortality after acute myocardial infarction. Serum creatine kinase MB estimated infarct size and 11 other prognostic variables were obtained in 317 patients. By Cox regression analysis the prognostic variables significantly related to mortality were identified: congestive heart failure, estimated infarct size, New York Heart Association class, number of previous infarcts, and age. Congestive heart failure and estimated infarct size were most strongly related to mortality. The relation between the prognostic variables and mortality was non-linear, and the variables influenced each others' relation to mortality. A prognostic index based on all five prognostic variables provided the best means of estimating the probability of survival after acute myocardial infarct. Neither serum creatine kinase MB estimated infarct size nor any of the other prognostic variables had a significant independent influence on mortality, and the probability of survival was high in the absence of any of the prognostic variables in combination.

Age Factors↗
PubMed1985

Dose-dependent effect of 17 beta-estradiol determined by growth curves and flow cytometric DNA analysis of a human breast carcinoma (T61) grown in nude mice.

An estrogen and progesterone receptor-positive human breast carcinoma (T61) grown in nude mice was exposed to 1.0, 0.1, 0.01, and 0.001 mg 17 beta-estradiol. These doses resulted in serum peak concentrations (day 1) of estradiol ranging from 3.5 X 10(-8) to 6.9 X 10(-10) M. The effect of the treatment was evaluated using growth curves and flow cytometric DNA analysis. The treatment induced a dose-dependent growth delay and dose-dependent changes in the cell cycle distribution. The cell cycle changes comprised a decrease in the G1 phase, an accumulation of cells in the S phase, and an increasing fraction of polyploid cells. The results suggest that estradiol induces a dose-dependent cell killing effect in the T61 human breast carcinoma. The correlation between the treatment-induced growth delay and the effect on the cell cycle distribution indicates that the changes in the cell cycle are a reflection of the estradiol-induced cell destruction. Since no tumor growth stimulation could be observed even at very low serum estradiol concentrations, the T61 human breast carcinoma may represent a new aspect in the study of human breast cancer.

Animals↗
PubMed1985

The Mini-Cap. External immobilization of facial fractures.

A method is described for external immobilization of the facial skeleton. The method is only indicated in a few cases. By means of Vitallium screws and a small head cap of plaster of Paris it is possible to achieve stiff, external immobilization of facial fractures, even when they are situated in the frontal bones. The Mini-Cap permits the patient to rest comfortably and costs very little.

Adolescent↗
PubMed1983

Cell kinetics in the epidermis of the toad Bufo bufo bufo (L.) after partial hypophysectomy followed by corticotrophin treatment (an autoradiographic study).

1. Cell kinetic parameters in the epidermis of partially hypophysectomized, ACTH-treated toads whose moulting frequency was increased threefold were studied using labelled thymidine and the autoradiographic technique. 2. The labelling index, length of S-phase and cycle time of stratum germinativum cells changed slowly as a function of the number of ACTH injections, and so did the migration of cells from stratum germinativum to stratum corneum. 3. A cell production in stratum germinativum of normal toads in excess of cell loss, as demonstrated by Levi & Nielsen (1982) should make it possible to maintain a status quo over a limited period of time following ablation of pars distalis and ACTH treatment.

Adrenocorticotropic Hormone↗
PubMed1983

Effect of 17 beta-oestradiol on growth curves and flow cytometric DNA distribution of two human breast carcinomas grown in nude mice.

The effect of 17 beta-oestradiol on a "receptor positive" and on a "receptor negative" human breast carcinoma grown in nude mice was studied. Experimental growth data were used to determine the effect on tumour growth. Flow cytometric DNA analysis (FCM) performed on tumour tissue obtained by sequential fine-needle aspirations was used to estimate the effect on the cell cycle. In the receptor-positive breast carcinoma, oestradiol induced complete tumour regression and characteristic cell cycle changes. In the receptor-negative breast carcinoma, no changes in tumour growth and cell cycle distribution could be demonstrated following the treatment. The results indicate that the oestradiol-induced cell kill could be explained to some extent by the induction of polyploid cells, which eventually die. Since the cell cycle changes monitored by FCM in the receptor-positive breast carcinoma appeared prior to any reduction in the tumour size, the results suggest that FCM may prove a valuable method in the early detection of tumour response to hormone treatment in human breast cancer.

Adult↗
PubMed1983

Effect of X irradiation on a heterotransplanted human colonic carcinoma before and after a change in the cellular DNA content.

A spontaneous change of cellular DNA content occurred in a hyperdiploid human colonic carcinoma grown in nude mice. After the change to hyperpentaploidy the tumor was exposed to single-dose X irradiation, and the effects on growth curves and on the cell cycle, determined by flow cytometric DNA analysis (FCM), were compared to results obtained with the tumor prior to the evolutionary event. The results showed that the radiation effects on growth rate and on cell kinetics had changed after the change in cellular DNA content. In the hyperpentaploid tumor the irradiation had no effect on the regrowth rate, whereas in the hyperdiploid tumor the postirradiation growth rate had decreased. As a consequence of the different effect on the regrowth rate of the tumors the growth delay was inadequate as a parameter for comparing the radiosensitivity. In the hyperpentaploid tumor the irradiation induced a partial synchronization of accumulated cells, whereas no synchronization effect was found in the hyperdiploid tumor. The redistribution time was 8-10 days for both tumors. The results indicate that clonal evolution may affect radiosensitivity, and that FCM analysis may prove to be a valuable method to provide rapid information on cellular synchronization and on redistribution time.

Animals↗