scispace - formally typeset
Search or ask a question
Author

P A Hall

Bio: P A Hall is an academic researcher. The author has contributed to research in topics: Nucleolus organizer region & Mitosis. The author has an hindex of 1, co-authored 1 publications receiving 451 citations.

Papers
More filters
Journal ArticleDOI
TL;DR: This brief overview will illustrate current ideas about cellular proliferation and its regulation and the advantages and disadvantages of the better known methods for assessing cellular proliferation in histopathological material.
Abstract: Introduction There can be little dispute that cellular proliferation is one of the most fundamental of biological processes.' Nor can there be disagreement over the importance of assessing cellular proliferation in the study of many biological processes: indeed, Leblond2 used such assessment for identifying the three major functional types of cellular populationnamely, static, conditional renewal, and continually renewing. The practice of histopathology involves direct or, more usually, indirect assessment of cellular proliferation (and related phenomena such as differentiation) in many situations.3 It is intended that this brief overview will illustrate current ideas about cellular proliferation and its regulation and the advantages and disadvantages of the better known methods for assessing cellular proliferation in histopathological material

453 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: The Annexin V assay offers the possibility of detecting early phases of apoptosis before the loss of cell membrane integrity and permits measurements of the kinetics of apoptotic death in relation to the cell cycle.

5,291 citations

Journal ArticleDOI
TL;DR: Data suggest that in normal tissues and lymphoid neoplasms, PCNA immunolocalization can be used as an index of cell proliferation, however, in some forms of neoplasia, including breast and gastric cancer and in vitro cell lines, the simple relation between PCNA expression and cell proliferation is lost.
Abstract: Proliferating cell nuclear antigen (PCNA) is a 36 kD nuclear protein associated with the cell cycle A monoclonal antibody, PC10, that recognizes a fixation and processing resistant epitope has been used to investigate its tissue distribution Nuclear PCNA immunoreactivity is found in the proliferative compartment of normal tissues PCNA immunoreactivity is induced in lectin stimulated peripheral blood mononuclear cells in parallel with bromodeoxyuridine incorporation and the number of cells with PCNA immunoreactivity is reduced by induction of differentiation in HL60 cells In non-Hodgkin's lymphomas a linear relation between Ki67 and PCNA staining was demonstrated These data suggest that in normal tissues and lymphoid neoplasms, PCNA immunolocalization can be used as an index of cell proliferation However, in some forms of neoplasia, including breast and gastric cancer and in vitro cell lines, the simple relation between PCNA expression and cell proliferation is lost In some breast and pancreatic tumours there is apparent deregulation of PCNA with increased expression in tissues adjacent to the tumours The over-expression in some tumours and in adjacent morphologically normal tissue may represent autocrine or paracrine growth factor influence on PCNA gene expression

1,441 citations

Journal ArticleDOI
TL;DR: The results challenge the dogma that the adult heart is a postmitotic organ and indicate that the regeneration of myocytes may be a critical component of the increase in muscle mass of the myocardium.
Abstract: Background The scarring of the heart that results from myocardial infarction has been interpreted as evidence that the heart is composed of myocytes that are unable to divide. However, recent observations have provided evidence of proliferation of myocytes in the adult heart. Therefore, we studied the extent of mitosis among myocytes after myocardial infarction in humans. Methods Samples from the border of the infarct and from areas of the myocardium distant from the infarct were obtained from 13 patients who had died 4 to 12 days after infarction. Ten normal hearts were used as controls. Myocytes that had entered the cell cycle in preparation for cell division were measured by labeling of the nuclear antigen Ki-67, which is associated with cell division. The fraction of myocyte nuclei that were undergoing mitosis was determined, and the mitotic index (the ratio of the number of nuclei undergoing mitosis to the number not undergoing mitosis) was calculated. The presence of mitotic spindles, contractile ri...

1,389 citations

Journal ArticleDOI
TL;DR: Monoclonal antibody Ki‐67 is of use in research, providing a means of measuring proliferative activity in a variety of conditions besides malignancy, and may prove of value in monitoring tumour response to established and trial therapies.
Abstract: Monoclonal antibody Ki-67 is a reliable and easy means of accurately assessing the growth fraction of human neoplasms. Although the number of long-term follow-up studies is limited, it does appear to provide valuable prognostic information particularly in lymphoproliferative disease. Since the estimation of growth fraction is only one factor influencing tumour behaviour it would be naive to believe that measurement of this parameter alone, no matter how accurately, would provide the clinician with definitive prognostic information for all tumours. The antibody is also of use in research, providing a means of measuring proliferative activity in a variety of conditions besides malignancy, and may prove of value in monitoring tumour response to established and trial therapies.

637 citations

Journal ArticleDOI
TL;DR: In situ end‐labelling stains cells with the morphological characteristics of apoptosis, and greatly simplifies their identification, and in two model systems, the number of labelled cells parallels thenumber of cells undergoing apoptosis as measured by alternative techniques.
Abstract: We have investigated the use of a novel technique, in situ end-labelling, as a means of the specific identification of apoptotic cells in formalin-fixed, paraffin-processed tissue sections. The technique relies on the presence of DNA strand breaks in apoptotic cells, caused by activation of endogenous nuclease activity during the process of cell death. These strands are labelled with a non-isotopic reporter molecule in the presence of a DNA polymerase, and labelled DNA is identified immunohistochemically. We show that in situ end-labelling stains cells with the morphological characteristics of apoptosis, and greatly simplifies their identification. Furthermore, in two model systems, the number of labelled cells parallels the number of cells undergoing apoptosis as measured by alternative techniques. The ability of the Klenow fragment of DNA polymerase to label apoptotic nuclei suggests that the characteristic DNA fragmentation seen during this process involves the formation of DNA breaks with a 5' overhang. In situ end-labelling will be valuable for the identification and quantitation of apoptosis in a range of normal tissues and in a variety of pathological states. However, the technique is not specific for programmed cell death, and results must be interpreted with caution and correlated with morphological criteria of apoptosis.

586 citations