On counter streaming centrifugation in the separation of cells and cell fragments

Lindahl, Per Eric

doi:10.1016/0006-3002(56)90175-5

Cited by 63 publications

(11 citation statements)

References 5 publications

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“…To achieve this aim, we employed centrifugal elutriation (Lindahl 1986) to ob tain large populations of cells at different stages of the cell cycle (Meistrich et al 1977;Hann et al 1985). A significant advantage of this procedure over those em ployed previously (Heintz and Roeder 1984) is that cells can be pumped into the rotor under normal growth con ditions and snap-cooled within 30 sec by washing with ice-cold buffer.…”

Section: The Proximal Hi Subtype-specific Consensus Element Is An Impmentioning

confidence: 99%

“…Popu lations of HeLa cells homogeneously separated in different phases of the cell cycle were obtained by centrifugal elutriation (Meistrich et al 1977;Lindahl 1986). In an average experiment, 3 X 10' to 4 X 10' cells were introduced into a 40-ml chamber of a Beckman rotor IE 5.0, running at a speed of 3500 rpm through a Masterflex peristaltic pump at a flow rate of 150 ml/ min.…”

Section: Cell-culture and Synchronization Proceduresmentioning

confidence: 99%

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Histone H1 subtype-specific consensus elements mediate cell cycle-regulated transcription in vitro.

Bella

Gallinari²,

McKinney³

et al. 1989

Genes & Development

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In this study we used nuclear extracts from centrifugally elutriated cell populations to study histone HI transcriptional regulation during the cell cycle. Analysis of mutations within the HI promoter establish that both of the HI subtype-specific consensus elements participate in induction of transcription upon entry into S phase. The DNA binding activity of H1TF2, which specifically interacts with the HI proximal subtype-specific element, is increased in S-phase nuclear extracts, whereas no increase in DNA binding is observed for the HI distal subtype-specific DNA transcription factor HlTFl or the H2b subtype-specific factor OTFl. These data strongly support the idea that histone gene subtype-specific transcription factors are important for S-phasedependent expression of histone genes. Further studies of these factors will be important for increased understanding of the transition from G^ to S phase of the mammalian cell cycle.[Key Words: Cell cycle; histone genes; in vitro transcription; centrifugal elutriation; transcription factors] Received July 11, 1989; revised version accepted September 7, 1989.The transition from Gi to S phase in the eukaryotic cell cycle results in the activation of chromosomal DNA synthesis and the increased production of a variety of activities required for synthesis or packaging of nascent DNA. The synthesis of most histone proteins is dramat ically induced at this time (Robbins and Borum 1967), because of both increased rates of transcription of the individual histone genes and accelerated post-transcriptional histone mRNA accumulation (Heintz et al. 1983;Sittman et al. 1983). Recent studies of the mechanisms regulating histone gene transcription demonstrated that promoter proximal DNA sequences (Artishevsky et al. 1987;Dalton and Wells 1988a;La Bella et al. 1988) and their cognate transcription factors (Fletcher et al. 1987;Dalton and Wells 1988b) are crucial for increased tran scription during S phase. It is our belief that a detailed knowledge of these proteins and their changing activi ties during S phase can lead to fundamental advances in our understanding of the cell cycle.The most specific information concerning the regula tion of histone gene expression during S phase has been obtained by analysis of histone H2b gene expression. We have demonstrated that a very highly conserved sub type-specific consensus element, containing the core octanucleotide ATTTGCAT and positioned immediately upstream from the TATA element, mediates cell-cycle regulation of H2b transcription (La Bella et al. 1988). The transcription factor that specifically interacts with this regulatory element has been purified and characterized ^Corresponding author. (Fletcher et al. 1987), although the precise mechanism by which this factor contributes to the S-phase induc tion of H2b transcription is not yet known. The H2b cell-cycle regulatory element is not present in genes en coding other histone subtypes. However, comparison of the H4, H2b, and HI promoters reveals that each pro moter contains a highly co...

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Section: The Proximal Hi Subtype-specific Consensus Element Is An Impmentioning

confidence: 99%

Section: Cell-culture and Synchronization Proceduresmentioning

confidence: 99%

Histone H1 subtype-specific consensus elements mediate cell cycle-regulated transcription in vitro.

Bella

Gallinari²,

McKinney³

et al. 1989

Genes & Development

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“…along the central axis of the conical chamber. It has been reported that conical shape of the chamber suppresses the formation of lamina1 flow [27]. Consequently, this nonlaminal flow gradient allows to maintain a stable boundary between loosely packed blood cells and plasma during displacement of PRP by medium.…”

Section: Disc U Sslo Nmentioning

confidence: 99%

Separation of platelet‐rich plasma by modified centrifugal elutriation

Persidsky

Ling

1982

J of Clinical Apheresis

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The Beckman centrifugal elutriation (CE) system is modified for the separation of platelet-rich plasma (PRP) from human and rabbit blood. The Beckman separation chamber is found inadequate for this purpose, and a new chamber of conical shape has been developed. Optimal flow rate for separating PRP from whole blood with the new chamber of 11.3 ml capacity is 3.5 ml/min while centrifuging at 2500 rpm or 700 g. Collection process takes about 4 minutes. This new process is based on the principle of centrifugal counterflow displacement and filtration, and is different from the CE process which is based on counterflow centrifugation and differential elution. About 90% of total platelets are recovered with this new process. The collected samples are free of leucocytes and contained only a few erythrocytes. Platelets collected by either differential centrifugation (DC) or new procedures are found to be similar in morphological characteristics, both being discoidal. Other characteristics such as aggregation response induced by ADP or epinephrine, serotonin-14C secretion, and survival of autologous platelets in rabbits are also found to be similar. However, ATP release induced by ADP is consistently higher from platelets prepared by our procedure than from those prepared by the DC procedure.

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“…This relation between labeling index and cell size was found in all our experiments. The probability that a cell in category z is in S-phase is proportional to its relative size within the cell size distribution of that cell subset z (20). This relation is expressed in Equation 3: in which P,(Vi) = the probability for a cell from subset z, with cell size Vi, to be in S-phase and A,, B, = constants for subset z.…”

Section: Proliferative Activity Of Individual Cell Types Within Bone mentioning

confidence: 99%

Calculation of S‐phase numbers of four major cell categories in human bone marrow from DNA‐flow cytometry and counterflow centrifugation data

et al. 1984

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Fractionation of heterogeneous cell populations into a number of fractions differing in cell size and composition, followed by measurement of DNA profiles and differential morphology of the samples allows the calculation, using a mathematical deconvolution procedure, of the cell proliferation of the individual categories. The method was applied to human bone marrow, fractionated by counterflow centrifugation into 10 to 15 fractions. Calculated percentage of S-phase cells in four major categories, including myeloid, erythroid, monocytic, and lymphoid cells, were in good agreement with data obtained by tritiated thymidine autoradiography.

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On counter streaming centrifugation in the separation of cells and cell fragments

Cited by 63 publications

References 5 publications

Histone H1 subtype-specific consensus elements mediate cell cycle-regulated transcription in vitro.

Histone H1 subtype-specific consensus elements mediate cell cycle-regulated transcription in vitro.

Separation of platelet‐rich plasma by modified centrifugal elutriation

Calculation of S‐phase numbers of four major cell categories in human bone marrow from DNA‐flow cytometry and counterflow centrifugation data

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