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Apoptosis, or programmed cell death, is a general mechanism for removal of unwanted cells from the immune system. It is characterized by chromatin condensation, a reduction in cell volume, and endonuclease cleavage of DNA into oligonucleosomal length fragments. Apoptosis is also accompanied by a loss of membrane phospholipid asymmetry, resulting in the exposure of phosphatidylserine at the surface of the cell. Expression of phosphatidylserine at the cell surface plays an important role in the recognition and removal of apoptotic cells by macrophages. Here we describe a new method for the detection of apoptotic cells by flow cytometry, using the binding of fluorescein isothiocyanate-labeled annexin V to phosphatidylserine. When Burkitt lymphoma cell lines and freshly isolated germinal center B cells are cultured under apoptosis inducing conditions, all cells showing chromatin condensation strongly stain with annexin V, whereas normal cells are annexin V negative. Moreover, DNA fragmentation is only found in the annexin V-positive cells. The nonvital dye ethidium bromide was found to stain a subpopulation of the annexin V-positive apoptotic cells, increasing with time. Our results indicate that the phase in apoptosis that is characterized by chromatin condensation coincides with phosphatidylserine exposure. Importantly, it precedes membrane damage that might lead to release from the cells of enzymes that are harmful to the surrounding tissues. Annexin V may prove important in further unravelling the regulation of apoptosis.  相似文献   
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Background  

Problematic waiting lists in public health care threaten the equity and timeliness of care provision in several countries. This study assesses different stakeholders' views on the acceptability of waiting lists in health care, their preferences for priority care of patients, and their judgements on acceptable waiting times for surgical patients.  相似文献   
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Summary: A statewide study to ascertain the number of ultrasound scans received by women in pregnancy, to identify the proportion having a scan at 16 to 20 weeks' gestation, and to establish where the scan at 16 to 20 weeks was performed was carried out between January, 1991 and June, 1992 in Victoria. Additional data were collected by midwives and entered on the perinatal morbidity statistics form routinely completed for all births. Of 52,319 women providing responses, 3.1% did not have a scan. Of the remaining 96.9% who had a scan, 73.5% were scanned at 16 to 20 weeks'gestation. Predictors of not having a scan were maternal birthplace and higher parity: previous perinatal death(s), and attendance at nonteaching hospitals predicted the opposite. Predictors of being scanned were location of hospital (country), maternal birthplace, higher parity and maternal age (< 20 years). Substantial differences in frequency and timing were found between hospitals attended. Factors associated with the pattern of scanning are not readily explicable in terms of risk of malformations or women's choices.  相似文献   
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Objective: to determine whether the incidence of perineal outcomes, including episiotomy, at the Royal Women's Hospital (RWH) Brisbane reflected trends reported in the literature.Design: retrospective record review.Setting: RWH Brisbane.Participants: 953 women who delivered vaginally at the RWH in 1986 and 1992.Measurements and findings: there was a decline in the episiotomy rate from 65% in 1986 to 36% in 1992. This was accompanied by an increase in the incidence of intact perinea and spontaneous perineal tears. There was no difference in the incidence of spontaneous third degree tears. The decline in the incidence of episiotomy was found when other factors, such as parity, were considered, with the exception of operative vaginal delivery, where no difference in the use of episiotomy was found. There was no significant increase in the number of babies with an Apgar score of <7 at one minute of age, despite a significant reduction in the use of episiotomy when delivering these babies (55% in 1986 and 19% in 1992; P<0.001). The second stage was significantly longer in 1992 (P<0.01).Key conclusions: the findings reflect the decline in the incidence of episiotomy reported in the literature. This decline in rate was accompanied by an increase in the length of second stage and in the incidence of both intact perinea and perineal tears. Lowering the incidence of episiotomy did not result in a rise in the rate of babies with an Apgar score of <7 at one minute.  相似文献   
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Objective: to compare teenagers who become unintentionally pregnant and teenagers who have never been pregnant but are using contraception on matters related to family/partner stability, and communication with a parent or stable sexual partner about sexual matters.Design: survey utilising self-completed questionnaire.Setting: a hospital antenatal clinic and community-based family planning clinic.Participants: 30 teenagers with an unplanned pregnancy and 31 ‘never-pregnant’ teenagers using contraception.Findings: the two groups were similar on demographic factors, mean age at which sexual intercourse was first experienced, total number of sexual partnerships, the number of teenagers having a current, regular boyfriend and mean length of the interval between when the teenagers first started going out with their boyfriend and when first sexual intercourse took place. Teenagers in the family planning clinic group were more likely to be living with both natural parents and to be still at school or in higher education. The mean length of time pregnant teenagers had been going out with their boyfriend was longer, they were more likely to be cohabiting with him and to be unemployed. Participants from the antenatal clinic group communicated more with their mothers about sexual matters than those in the family planning clinic group, who were more likely to seek this information from books. The family planning clinic participants were more likely to discuss personal rules and values with friends than those in the antenatal clinic group.Implications for practice: to develop understanding of factors predisposing to unplanned pregnancy during adolescence and to implement measures to counter them, further studies to examine the influence of teenagers' perceptions of family relationships and future life prospects on contraception use and unplanned pregnancy were identified.  相似文献   
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