In situ end-labelling detects DNA strand breaks in apoptosis and other physiological and pathological states

Increased apoptosis in the cingulate sulcus of newborn piglets following transient hypoxia-ischaemia is related to the degree of high energy phosphate depletion during the insult

An increase in the number of cells undergoing apoptosis was observed in the cingulate sulcus of newborn piglets 48 h after a global hypoxic-ischaemic insult. Apoptotic death was identified morphologically (by light and electron microscopy) and by DNA fragmentation, detected by in situ end labelling. The number of apoptotic cells was directly related to the degree of high-energy phosphate depletion during hypoxia-ischaemia, measured using continuous 31P magnetic resonance spectroscopy. These results may have implications for the understanding and treatment of perinatal hypoxic-ischaemic brain injury.

The extent of apoptosis in different types of high grade prostatic carcinoma

Apoptosis is the genetically mediated mechanism by which individual cells are deleted from living tissues. The extent of apoptosis in human tumours has not been examined in detail. In this study, apoptotic indices were assessed semiquantitatively by light microscopy in routine haematoxylin and eosin (H & E) stained sections of 15 high-grade carcinomas of the prostate by light microscopy, using the 40 x objective, counting 2000-2500 tumour cells per case. The mean apoptotic index for nine solid undifferentiated carcinomas was 1.7% (range 0.2-2.4%), for three small cell undifferentiated carcinomas 25.2% (range 10-37%), and for three secondary transitional cell carcinomas of the prostate 5.5% (range 2.4-9.1%). In general, apoptosis was easily identified, using the 40 x objective. There were minor variations in apoptosis from field to field in each tumour, and greater variability in the apoptotic index was observed among the small cell undifferentiated carcinomas and transitional cell carcinomas. In conclusion, assessment of apoptosis in routine H & E sections of human tumours is feasible, but it remains to be determined whether the extent of apoptosis correlates with other determinants of biological behaviour.

Apoptotic cell death in human gastric carcinoma: analysis by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling

We have examined the occurrence of apoptotic cell death in formalin-fixed, paraffin-embedded human gastric carcinoma specimens by the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) method. The specificity of the TUNEL signals was confirmed by the omission of either TdT or biotinylated dUTP as negative controls, and by pretreatment with DNase I as a positive control. Careful observation of routine hematoxylin and eosin-stained sections showed a few tumor cells with apoptosis, especially in well-differentiated carcinomas. Intense TUNEL signals were frequently observed even in ordinary, non-pyknotic nuclei of tumor cells, and occasionally also in nuclear fragments corresponding to apoptotic bodies. Apoptotic indices (number of apoptotic cells/total number of tumor cells) ranged between 7.7 and 14.5% (mean, 10.9%) in nine well-differentiated carcinomas and between 2.7 and 7.5% (mean, 4.0%) in five which were poorly differentiated, the mean number being significantly higher in the former (P < 0.01). No apparent correlation was found between apoptosis and the expression of proliferating cell nuclear antigen, P53 or Le(y) in the present study. This high frequency of apoptosis, implying cell loss, may be related to the slow-growing nature of well-differentiated carcinomas. Poorly differentiated carcinomas, including scirrhous gastric carcinomas, showed a lower incidence of apoptosis, indicating the existence of an escape mechanism from the process.

Apoptosis related antigen, Le(Y) and nick-end labeling are positive in spinal motor neurons in amyotrophic lateral sclerosis

Expression of Le(Y), a difucosylated type 2 chain determinant, has been previously identified as a characteristic of cells undergoing apoptosis. Immunohistochemistry using an antibody for Le(Y), as well as nick-end labeling for the detection of DNA breaks, was done on cervical spinal cord sections from ten patients with amyotrophic lateral sclerosis (ALS) and nine patients who had died from other causes. Le(Y)-positive immunoreactivity was seen in the motor neurons of seven ALS cases, but in none of the other cases. Nick-end labeling was also positive in four ALS cases. Double staining of motor neurons by anti-Le(Y) antibody and nick-end labeling was shown in these cases. Other Le(Y)-positive structures, such as reactive astrocytes and fat-laden microglia/macrophages in the lateral and anterior columns, were negative for nick-end labeling. These results suggest that the mechanism of cell death in the spinal motor neurons of ALS may be apoptosis.

Death from inside out: an overview

Although a type of cell death strategically suited to participating in developmental processes has been well known for nearly thirty years, it is only in the recent past that the extraordinary ubiquity of such death has been appreciated. Apoptosis, a term first employed to describe such death defined in structural terms, is associated with a stereotyped set of effector processes, and is driven by genes most of which are familiar as oncogenes or oncosuppressor genes. Dysregulation of apoptosis leads to diseases of enormous social importance such as cancer and AIDS.

Liver cell death: patterns and mechanisms

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