SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
The authors present considerations about death and brain death concepts, as well the legal aspects for its diagnosis in Brazil. They also present the UNICAMP Protocol for the Diagnosis of Brain Death, revised and according with the current law, with standard techniques for the diagnostic exam. They emphasize the importance of a mature ethical position for this frequent and challenging situation.
Explore the source record for details and available documents.
OBJECTIVE: To investigate the relationship between components of death concept (preoccupation with death, death as a pleasant state, and death as final) and suicidal behavior in adolescents. METHOD: The death concepts of 51 suicidal inpatients, 102 nonsuicidal inpatients, 36 emergency room suicidal subjects, and 81 normal controls were compared using Pfeffer's Child Suicide Potential Scale. In addition, the IQ level as well as emotions that potentially influence the death concept were measured. RESULTS: Both groups of suicidal adolescents evaluated death as more pleasant than the nonsuicidal groups. All the study groups equally perceived death as a final state. Suicidal inpatients were more preoccupied with death than nonsuicidal inpatients, but surprisingly among all study groups, including normal controls, the emergency room suicidal subjects were the least preoccupied with death. Partialing out depression, anxiety, and aggression specifically augmented the association between preoccupation with death and suicidality. Thus the relationship between death concept and suicidality appears to be a direct one. No correlation was found between suicidality and intelligence level. CONCLUSIONS: Elements of death concept distinguish suicidal from nonsuicidal as well as between hospitalized versus nonhospitalized suicidal adolescents. Thus the death concept evaluation is potentially valuable in the assessment of adolescents with a high risk for suicide.
To examine the differences between parents' and nonparents' beliefs regarding the concept of death in children, 352 individuals answered a demographic survey. Questions concerning beliefs about the age at which children develop the concept of the irreversibility of death were included on the survey. Parents believed that the concept is developed at an earlier age than did nonparents, and also believed that the concept is developed at an earlier age than has been revealed by most research.
This review of the empirical literature on the development of the concept of death focuses on 3 components of that concept: irreversibility, nonfunctionality, and universality. These findings overall suggest that the majority of healthy children in modern urban-industrial societies achieve an understanding of all 3 components between 5 and 7 years of age. Since this is also the age at which most children make the transition from preoperational to concrete-operational thinking, some relationship between these 2 processes seems likely. However, attempts to empirically validate that relationship have thus far yielded ambiguous results. Possible reasons for this ambiguity are suggested.
Explore the source record for details and available documents.
Programmed cell death or apoptosis occurs under physiological conditions as a result of physiological effectors. It is a relatively slower process and requires active participation of the cell in the suicidal mechanism. Apoptosis is controlled by precise intrinsic genetic programme and may be induced by almost all those stimuli causing necrosis. The role played by the intensity in determining the death process and the underlying mechanism is imperfectly understood. Morphologically apoptotic cells appear as small condensed body. The chromatin is dense and fragmented, packed into compact membrane-bound bodies together with randomly distributed cell organelles. The plasma membrane loses its characteristic architecture and shows extensive blebbing. It buds off projections so that the whole cell may split into several membrane-bound apoptotic bodies. Significant chemical changes take place in the plasma membrane. This helps in recognition of the apoptotic bodies by phagocytes. At this moment it is unclear if all cells can undergo apoptosis or it is a characteristic of only some tissues which are predisposed to apoptotic death being directly under the control of hormones or growth factors. Experimental studies aimed at comparison of induction of apoptosis in cells of different origin are warranted to elucidate this point. Biochemically a pre-commitment step for induction of death programmation through macromolecular synthesis is essential for most systems. The double-stranded linker DNA between nucleosomes is cleaved at regular inter-nucleosomal sites through the action of a Ca2+, Mg(2+)-sensitive neutral endonuclease. Zinc is a potent inhibitor of the enzyme. Calcium probably plays a key controlling role in activation of the enzyme since prevention of Ca2+ increase prevents endonuclease activation. It is becoming evident that signal transduction through appropriate receptors control the Ca2+ flux in the cells. Most apoptotic cells require synthesis of RNA and proteins. Delay or abrogation of apoptosis by inhibition of macromolecular synthesis is well known. The dying cells show high mRNA levels for several enzymes. Several degradative enzymes become active. Regulatory proteins maintain control over the apoptotic cascade. At the molecular level, search has been initiated for the mammalian equivalents of the cell death (ced) gene. Activation of several specific genes is indicated. Specific expression of cell death-associated gene products (e.g. TRPM-2/SGP-2) has been reported in several unrelated apoptotic cell systems. Sequential induction of c-fos, c-myc and 70 kDa heat shock protein is reported. Studies demonstrate that certain genes must remain in a transcriptionally active demethylated state during programmed cell death. Recent evidences clearly indicate that apoptosis may be positively or negatively modulated by certain genes.(ABSTRACT TRUNCATED AT 400 WORDS)
Explore the source record for details and available documents.
Programmed cell death, or apoptosis, corresponds to a sequence of intracellular events that lead to cell death. It has been shown that apoptosis is necessary in some physiological conditions such as embryogenesis, homeostasis of the immune system, erythropoiesis, etc. Some xenobiotics can induce apoptosis at lower doses and necrosis at higher doses. When a cell dies, it is either by apoptosis or by necrosis, and there are many differences between these two deaths. Apoptosis begins by a pre-commitment phase, which is reversible; during this phase the cell has a high level of second messengers. The commitment phase then follows and is irreversible, even when the xenobiotic that triggered the induction is removed. Most often, apoptotic cell death requires synthesis of macromolecules, the inhibition of their synthesis can prevent it. The cell undergoes important morphological changes during apoptosis, its volume decreases when its density increases. Then chromatin becomes granular, intensively osmiophilic, it condenses along the nuclear membrane. Later, chromatin disintegrates into small granules which will be phagocytized. One of the most important characteristics of the programmed cell death is the activation of an endonuclease, that gives rise to DNA fragments of 180-200 base pairs or multiples of these numbers; then after electrophoresis, the DNA gives the appearance of a ladder. Apoptotic cells can be characterized after classic staining, and flow cytometry; they can be separated from other cells by centrifugation on a gradient of density. It has been hypothesized that cell transformation could be due to a sudden resistance to apoptosis. However, the most interesting aspect in oncology recently demonstrated is that well-known anticancer drugs are able to induce apoptosis. One can hope that the discovery of new targets for anticancer drugs could lead to discovering new drugs that could be more active.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.