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1.
Abstract

Both breastfeeding initiation and duration increased in Peru during 1977–86. Although one would have expected that the average incidence and duration of breastfeeding would have declined as a result of changes in population characteristics, the potential for an overall decline was more than overcome by changes in behavior. A net increase in initiation and duration is shown for all subgroups of interest. The largest absolute increases are documented for children who, in 1977, were the least likely to be breastfed and who were breastfed for the shortest durations.  相似文献   

2.

Background

Breastfeeding is one of the components of Primary Health Care in Ethiopia. In Ethiopia a wide range of harmful infant feeding practices has been documented despite the implementation of infant and young child feeding guidelines. However, there is no well documented study of women’s perception of breastfeeding patterns and factors associated with delayed initiation of breastfeeding (with timely initiation of breastfeeding being within the first hour) in rural communities of Arba Minch Zuria.

Methods

A community-based cross-sectional study was carried out in Arba Minch Zuria from January to February, 2012. Quantitative data were collected from a sample of 383 respondents supplemented by qualitative data generated using in-depth interviews of 10 key informants. A multivariate logistic regression analysis was used to identify the predictors of delayed initiation of breastfeeding practices. Qualitative data were analyzed using thematic frameworks.

Results

In the rural communities of Arba Minch Zuria almost all mothers (98.2%) have ever breastfed their children. More than three-fourth (89%) of mothers provided colostrum to their infants while others discarded the first milk until the white milk was produced. A large number of mothers (42.8%) started breastfeeding one hour after childbirth. Delayed initiation of breastfeeding was positively associated with lack of maternal education (AOR 1.91; 95% CI 1.02, 3.44). Maternal knowledge about the duration of exclusive breastfeeding (AOR 0.39; 95% CI 0.15, 0.93), attending a primary health education (AOR 0.74; 95% 0.15, 0.98) and health personnel support for women at delivery time (AOR 0.52; 95% CI 0.21, 0.58) were inversely associated with delayed initiation of breastfeeding practices.

Conclusions

A large number of mothers (42.8%) were short of the national and global recommendations about breastfeeding initiation. Therefore, sustained health and community based nutritional education is recommended for pregnant and lactating mothers to promote optimal breastfeeding for the initiation of breastfeeding practices using health extension workers and local community resource people as key actors.
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3.

Background

The World Health Organization recommends promoting exclusive breastfeeding for six months. Women often end breastfeeding earlier than planned, however women who continue to breastfeed despite problems often experience good support and counselling from health professionals. The aim of this study was to evaluate the effects of a process-oriented training in breastfeeding support counselling for midwives and child health nurses, on women’s satisfaction with breastfeeding counselling, problems with insufficient breast milk and nipple pain in relation to exclusive breastfeeding shorter or longer than 3 months.

Methods

An intervention through process-oriented training for health professionals regarding support in childbearing and breastfeeding took part in the south west of Sweden. This study was conducted in Sweden, in 2000 - 2003. Ten municipalities were paired, and within each pair, one was randomly assigned to the group of five intervention (IG) municipalities and one to the group of five control municipalities. Primiparas (n?=?540) were invited to participate in a longitudinal study to evaluate the care they received. A survey was distributed at 3 days, 3 months and 9 months postpartum. Data collection for control group A (n?=?162) started before the intervention was initiated. Data for control group B (n?=?172) were collected simultaneously with the intervention group (IG) (n?=?206). Women were also divided into two groups depending on whether they exclusive breastfed?<?3 months or?≥?3 months.

Results

Women in IG were more satisfied with the breastfeeding counselling (p?=?0.008) and felt the breastfeeding counselling was more coherent (p?=?0.002) compared to control groups, when exclusive breastfeeding was?<?3 months. In addition fewer women in the IG, among the group exclusively breastfeeding?<?3 months, had problems with insufficient breast milk compared to the control groups (p?=?0.01).

Conclusion

A process-oriented training for health professionals in support influenced women’s ability to solve breastfeeding problems such as the experience of insufficient breast milk production. Women with exclusive breastfeeding lasting?≥?3 months more often had breastfeeding duration in line with their planned breastfeeding duration, compared to women who had breastfeeding duration?<?3 months.

Trial registration

ACTRN12611000354987
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4.
3-deoxyadenosine, applied to meristematic populations, proves to be a drug which causes an accumulation of cells in the prophase. Analysing its effects, we find that cells in prophase continue to go through their chromosome cycle and thus that the specific effect of the drug is to block the rupture of the nuclear membrane, giving rise to a process of endomitosis in the cells treated. If the drug is applied to synchronous, labelled cells, analysis of its effects reveals that they occur at the prophase level, while the remaining stages of mitosis, if not arrested in the prophase, proceed normally.The data here brought forward as to the effects of 3-deoxyadenosine, like those relating to the effects of other drugs which block RNA synthesis at the prophase level, suggest that this stage in the cell division cycle is of great importance in the evolution of the mitotic process.  相似文献   

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6.
Was the initiation of translation in early eukaryotes IRES-driven?   总被引:1,自引:0,他引:1  
The initiation of translation in eukaryotes generally involves the recognition of a 'cap' structure at the 5' end of the mRNA. However, for some viral and cellular mRNAs, a cap-independent mechanism occurs through an mRNA structure known as the internal ribosome entry site (IRES). Here, I postulate that the first eukaryotic mRNAs were translated in a cap-independent, IRES-driven manner that was then superseded in evolution by the cap-dependent mechanism, rather than vice versa. This hypothesis is supported by the following observations: (i) IRES-dependent, but not cap-dependent, translation can take place in the absence of not only a cap, but also many initiation factors; (ii) eukaryotic initiation factor 4E (eIF4E) and eIF4G, molecules absolutely required for cap-dependent translation, are among the most recently evolved translation factors; and (iii) functional similarities suggest the evolution of IRESs from spliceosomal introns. Thus, the contemporary cellular IRESs might be relics of the past.  相似文献   

7.
Expression of the two isoforms p55 and p40 of HIV-1 Gag proteins relies on distinct translation initiation mechanisms, a cap-dependent initiation and two internal ribosome entry sites (IRESs). The regulation of these processes is complex and remains poorly understood. This study was focused on the influence of the 5'-UTR and on the requirement for the eukaryotic initiation factor (eIF)4F complex components. By using an in?vitro system, we showed substantial involvement of the 5'-UTR in the control of p55 expression. This highly structured 5'-UTR requires the eIF4F complex, especially RNA helicase eIF4A, which mediates initiation at the authentic AUG codon. In addition, the 5'-UTR regulates expression in an RNA concentration-dependent manner, with a high concentration of RNA triggering specific reduction of full-length Gag p55 production. HIV-1 genomic RNA also has the ability to use a strong IRES element located in the gag coding region. We show that this mechanism is particularly efficient, and that activity of this IRES is only poorly dependent on RNA helicase eIF4A when the viral 5'-UTR is removed. HIV-1 genomic mRNA exhibits in?vitro translational features that allow the expression of Gag p55 protein by different mechanisms that involve different requirements for eIF4E, eIF4G, and eIF4A. This suggests that HIV-1 could adapt to its mode of translation according to the availability of the initiation factors in the infected cell.  相似文献   

8.
In order to obtain more insight into the possible role of cyclic AMP or cyclic GMP in modulating the initial cellular processes following activation of lymphocytes, we measured the effects of the T-cell mitogen concanavalin A and other substances including hormones on the cyclic nucleotide levels in human peripheral blood lymphocytes. The enzyme activities of the corresponding nucleotide cyclases, adenylate cyclase and guanylate cyclase were measured in both isolated plasma membranes or the cytosol of resting or concanavalin A stimulated rabbit thymocytes. Concanavalin A in a mitogenic concentration of about 5-10 micrograms/ml caused small, but consistent increases in cAMP but no changes in cGMP levels during the first hour of activation. Concomitantly, the specific activity of plasma membrane-bound adenylate cyclase was always increased at least 1.5-fold 30 min after stimulation of rabbit thymocytes with concanavalin A, but no effect could be detected on the specific activities of plasma membrane-bound or soluble guanylate cyclase. At high, supraoptimal concentrations of concanavalin A (more than 20 micrograms/ml) cAMP levels dramatically increased in human lymphocytes within minutes, but cGMP levels again were unaffected. Forskolin and beta-adrenergic hormones elevated cAMP in human lymphocytes, whereas cGMP levels were increased by the addition of sodium nitroprusside or alpha-adrenergic hormones. Sodium nitroprusside, in concentrations which elevated cGMP in human lymphocytes, had no influence on the incorporation of [3H]uridine into RNA of resting or concanavalin A stimulated human lymphocytes. Addition of forskolin resulted in an increase of cAMP levels and a dose-dependent decrease of [3H]uridine incorporation into RNA of concanavalin A-stimulated lymphocytes with no effect on resting lymphocytes. The data suggest that cGMP does not play a role in the initial phase of mitogenic activation of lymphocytes, whereas cAMP may be involved in the blast transformation process as an inhibitory signal.  相似文献   

9.
The initiation mess?   总被引:7,自引:3,他引:4  
This review concerns the mechanisms which control initiation of chromosome replication in enterobacteria with respect to cell growth. Initiation control is commonly separated into positive and negative regulatory mechanisms. Four main points are advanced concerning these different aspects of initiation control. (i) The average concentration of the initiator protein DnaA is proportional to the origin concentration, i.e. the origin per cell mass ratio and, thus, inversely proportional to the very often used term of the 'initiation mass'. (ii) The time of initiation of chromosome replication in the cell cycle is set by DnaA protein accumulating to a threshold level, which in concert with a number of other factors allows for a co-operative formation of the initiation complex. (iii) The time of initiation is not determined by the interaction with these other factors or by the transient interaction between newly replicated origins ( oriC  ) and the cell surface. (iv) The aberrant initiation phenotype observed in various mutants, including dnaA (ts) mutants, might be due to a defective pre-initiation DnaA– oriC interaction or it might be due to a defect in the protection of newly initiated origins from reinitiation. Many of these points are discussed and evaluated in view of recent developments concerning the regulation of chromosome replication in Escherichia coli  相似文献   

10.
Eukaryotic protein synthesis initiation factor 2 (eIF-2) from rat liver has been resolved into two subfractions by anion-exchange chromatography on DEAE-cellulose. One of these contained all three components (eIF-2α, eIF-2β, eIF-2γ) characteristic of mammalian eIF-2, whilst the other fraction contained only two. By a number of criteria these were shown to be eIF-2α and eIF-2γ. The absence of eIF-2β from this fraction was not due to its proteolytic degradation during purification since it was unaffected by the inclusion of a range of proteinase inhibitors in the isolation media. The properties of eIF-2 containing or lacking eIF-2β have been directly compared. It was found that eIF-2β was not required for the binding of guanine nucleotides to eIF-2 or for formation of ternary initiation complexes with GTP and the initiator tRNA. eIF-2 lacking eIF-2β was able to form 40 S initiation complexes and the presence of eIF-2β was also unnecessary for the stimulation of eIF-2 activity by the recycling factor, eIF-2B. Some of these findings are at variance with previous reports in which eIF-2β was removed proteolytically. The role of eIF-2β in the overall physiological function of eIF-2 remains to be elucidated.  相似文献   

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13.
Mexico has shown a worrisome decrease in breastfeeding indicators, especially in the lowest socioeconomic level. Improving breastfeeding protection, promotion, and support services through workforce development is a key area of intervention. The objective of this study is to assess the influence on breastfeeding knowledge and abilities of a semi-virtual training for primary healthcare providers assisting beneficiaries of PROSPERA in Mexico, which is one of the largest conditional cash-transfer programs in the world. Two independent cross-sectional samples of healthcare providers were drawn at baseline and post-intervention in three states of Mexico. Baseline data were collected among primary physicians, registered nurses and nurse technicians (i.e. unit of analysis) on July 2016 (n = 529) and post-training between March and April 2017 (n = 211). A 19-item telephone questionnaire assessed providers’ general knowledge about breastfeeding, breastfeeding benefits and clinical aspects of breastfeeding, clinical ability to solve problems and abilities to overcome breastfeeding challenges. The effects of the training were assessed through a propensity score matching (PSM) stratified by types of providers (i.e. physicians, registered nurses, nurse technicians). The PSM analysis showed significant improvements among all providers in the general knowledge about breastfeeding (around 20 percentage points [pp]) and knowledge about breastfeeding benefits (approximately 50 pp). In addition, physicians improved their knowledge about clinical aspects of breastfeeding (7 pp), while registered nurses improved in their ability to solve breastfeeding problems (14 pp) and in helping mothers overcome breastfeeding challenges (12 pp). Promoting a breastfeeding enabling environment in Mexico to improve breastfeeding rates will require improving the knowledge and skills of healthcare providers. While a semi-virtual training showed large improvements in knowledge, developing skills among providers may require a more intensive approach.  相似文献   

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17.
To investigate the initiation of primary succession in a cold-desert playa-dune complex, we studied the large-scale (2000 m) seed (diaspore) dispersal patterns at Mono Lake, California. Seeds of seven of the ten species reaching the barren playa had wind-dispersal adaptations. Rates of dispersal (numbers of seeds per square metre per day) were as much as three orders of magnitude lower on the playa than in the diverse dune vegetation. However, seed input appeared sufficient to reach potential safe sites on the playa, with a peak input of 66 ± 8 total seeds·m·d. The smooth playa surface, the virtual absence of aboveground barriers, and the high windspeed environment promote the long-distance dispersal of seeds (at least 1300 m for Chrysothamnus spp. and at least 700 m for Sarcobatus vermiculatus). The large spatial scale of sampling revealed a relatively high seed input onto the playa by the dominant pioneer species S. vermiculatus, despite the low abundance of parent vegetation in this region. All of these results implicate low rates of seed entrapment as an obstacle to establishment on this desert playa, rather than a lack of seed input.  相似文献   

18.
19.
In none of the 92 published prokaryotic sequences is a translation codon preceeded by UAG as the first "termination codon". In most cases the UAA or UGA is close to the initiation codon and may be part of the ribosome recognition signal.  相似文献   

20.
Sarcophaga argyrostoma pupae otherwise destined to diapause can be made to initiate prompt, complete adult development by injection of 0.2 to 0.3 μg β-ecdysone/g body weight, if the injection is given soon after head eversion at the time ecdysone levels would normally increase in developing animals. At these doses some animals show only the earliest signs of adult development and then enter diapause. After two weeks in diapause, a 40-fold higher dose (10 μg/g) is required to initiate development promptly. β-ecdysone can also accelerate the termination of diapause after a time delay which is dose-dependent. Doses of 6 to 10 μg/g lead to hyperhormonal abnormalities affecting antennae, genitalia, and bristle orientation.  相似文献   

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