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J van der Bosch

Publications and source records attributed to J van der Bosch.

29 records · Page 2Linked to original sources
PubMed1982

In vitro responses of nude mouse-xenografted human colon carcinomas exposed to doxorubicin derivatives in tissue culture and in the mouse.

In vitro responses of 4 xenografted human colon tumors (T183, T219, T245, and T348) to various doses of 4'-deoxydoxorubicin have been investigated. The individual tumors showed marked differences in drug responsiveness, ranging from high sensitivity at low doses (T219; 125 ng/ml) to very low sensitivity at high doses (T245; 4000 ng/ml). The sensitivity ranking deduced from these in vitro experiments correlates well with the ranking deduced earlie (Guiliani et al., Int. J. Cancer, 27: 5-13, 1981) from in vivo drug treatments of transplants of these tumors in the nude mouse. The effect of in vitro drug treatment (4'-deoxydoxorubicin; 250 ng/ml; 1-hr incubation) on the in vivo growth of one of the tumors, T219, in nude mice was investigated. Growth of the tumor in nude mice was markedly delayed by pretreatments in vitro with 4'-deoxydoxorubicin. Furthermore, in vitro responsiveness of the T219 tumor was investigated following in vivo and in vitro treatment of the tumor with 4'-deoxydoxorubicin. Both of the pretreatments produced very similar decreases in drug responsiveness to all of the doxorubicin derivatives tested (4'-deoxydoxorubicin, 4'-O-methyldoxorubicin, 4'-epidoxorubicin, 4-demethoxydoxorubicin, and N-trifluoroacetyldoxorubicin-14-valeriate).

Animals↗
PubMed1981

Growth characteristics of primary tissue cultures from heterotransplanted human colorectal carcinomas in serum-free medium.

Procedures are described for the preparation of reproducible primary cultures from human colorectal tumors transplanted in the athymic nude mouse and for the quantitative evaluation of growth by means of counting suspensions of nuclei from these cultures with a Coulter counter. Growth curves of primary cultures from 11 colorectal tumors in serum-free medium are shown and discussed with respect to the in vitro conditions to be met for the propagation of in vivo stem cell populations.

Animals↗
PubMed1980

Age-dependent decrease of growth responsiveness in density inhibited 3T3 cell populations and their interactions with SV 40-3T3 cells.

An aging process has been detected in stationary 3T3 cell cultures, especially in the presence of plasma-derived serum (PDS) from adult bulls. It leads to irreversible conversion of an increasing percentage of initially responsive cells of a stationary population into cells unresponsive to growth stimulation by newborn calf serum (NBCS) or reseeding at low cell density in the presence of NBCS. These unresponsive cells are viable in the sense that, following trypsinization, they reattach and spread on a new culture plate and can be maintained for many days. The conversion process is accelerated by increasing PDS concentration. It is antagonized by NBCS. It is accompanied by enhancement of growth-inhibiting interactions exerted by stationary 3T3 cell populations on SV 40-3T3 cells.

Animals↗
PubMed1975

Fusion of dipalmitoylphosphatidylcholine vesicle membranes induced by concanavalin A.

The temperature dependence of fatty acid spin label resonance spectra and freeze fracture micrographs of sonicated dipalmitoylphosphatidylcholine vesicles in the absence and presence of concanavalin A demonstrate a strong interaction of concanavalin A with these lipid membranes, which results in fusion of the vesicles. The rate of this reaction as followed with use of magnetic resonance exhibits a pronounced maximum at 36 degrees, the midpoint of the phase transition range of dipalmitoylphosphatidylcholine vesicles. This maximum is discussed in terms of structural fluctuations, which are maximal in the phase transition range of the membranes.

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PubMedDate not supplied

Density-dependent growth inhibiting interactions between 3T3 and SV40-3T3 cells in mixed cultures.

3T3 cells are shown to reduce SV40-3T3 cell population growth in a denisty-dependent manner in co-cultures of 3T3 and SV40-3T3 cells. The development of this inhibitory activity roughly parallels the development of density-dependent inhibition of growth in homogeneous 3T3 control cultures. The extent of reduction of SV40-3T3 growth can be manipulated by pretreatment of 3T3 cells with a high serum concentration. SV40-3T3 growth rates are reduced by factors between 10 and 20 under optimum inhibitory conditions as compared to SV40-3T3 growth in control cultures.

Animals↗
PubMedDate not supplied

Density-dependent growth adaptation kinetics in 3T3 cell populations following sudden [Ca2+] and temperature changes. A comparison with SV40-3T3 cells.

Lowered extracellular [Ca2+] cause low growth rates and low stationary cell densities in 3T3 cell cultures as compared to physiological [Ca2%]. Under otherwise constant conditions the extracellular [Ca2+] determines a stable stationary cell density, which can be reached by increase of net cell number or decrease of net cell number, depending on cell density at the time of [Ca2+] adjustment. SV40-3T3 cells do not show this [Ca2+] dependency. At 39 degrees C 3T3 and SV40-3T3 cell populations show an increased growth rate at low cell densities as compared to cell populations at 35 degrees C. Approaching the stationary density the growth rate of both cell sorts is reduced faster at 39 degrees C than at 35 degrees C, leading to lower stationary cell densities at 39 degrees C than at 35 degrees C. A temperature change from 39 degrees C to 35 degrees C or in the opposite direction can affect the stationary cell density of 3T3 cell populations only if applied before reduction of growth rate by density-dependent growth-inhibiting principles has taken place.

Animals↗