19 research outputs found

    Distribution of melanopsin positive neurons in pigmented and albino mice: evidence for melanopsin interneurons in the mouse retina.

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    Here we have studied the population of intrinsically photosensitive retinal ganglion cells (ipRGCs) in adult pigmented and albino mice. Our data show that although pigmented (C57Bl/6) and albino (Swiss) mice have a similar total number of ipRGCs, their distribution is slightly different: while in pigmented mice ipRGCs are more abundant in the temporal retina, in albinos the ipRGCs are more abundant in superior retina. In both strains, ipRGCs are located in the retinal periphery, in the areas of lower Brn3a(+)RGC density. Both strains also contain displaced ipRGCs (d-ipRGCs) in the inner nuclear layer (INL) that account for 14% of total ipRGCs in pigmented mice and 5% in albinos. Tracing from both superior colliculli shows that 98% (pigmented) and 97% (albino) of the total ipRGCs, become retrogradely labeled, while double immunodetection of melanopsin and Brn3a confirms that few ipRGCs express this transcription factor in mice. Rather surprisingly, application of a retrograde tracer to the optic nerve (ON) labels all ipRGCs, except for a sub-population of the d-ipRGCs (14% in pigmented and 28% in albino, respectively) and melanopsin positive cells residing in the ciliary marginal zone (CMZ) of the retina. In the CMZ, between 20% (pigmented) and 24% (albino) of the melanopsin positive cells are unlabeled by the tracer and we suggest that this may be because they fail to send an axon into the ON. As such, this study provides the first evidence for a population of melanopsin interneurons in the mammalian retina

    A role for the outer retina in development of the intrinsic pupillary light reflex in mice.

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    Mice do not require the brain in order to maintain constricted pupils. However, little is known about this intrinsic pupillary light reflex (iPLR) beyond a requirement for melanopsin in the iris and an intact retinal ciliary marginal zone (CMZ). Here, we study the mouse iPLR in vitro and examine a potential role for outer retina (rods and cones) in this response. In wild-type mice the iPLR was absent at postnatal day 17 (P17), developing progressively from P21-P49. However, the iPLR only achieved ∌ 30% of the wild-type constriction in adult mice with severe outer retinal degeneration (rd and rdcl). Paradoxically, the iPLR increased significantly in retinal degenerate mice >1.5 years of age. This was accompanied by an increase in baseline pupil tone in the dark to levels indistinguishable from those in adult wild types. This rejuvenated iPLR response was slowed by atropine application, suggesting the involvement of cholinergic neurotransmission. We could find no evidence of an increase in melanopsin expression by quantitative PCR in the iris and ciliary body of aged retinal degenerates and a detailed anatomical analysis revealed a significant decline in melanopsin-positive intrinsically photosensitive retinal ganglion cells (ipRGCs) in rdcl mice >1.5 years. Adult mice lacking rod function (Gnat1(-/-)) also had a weak iPLR, while mice lacking functional cones (Cpfl5) maintained a robust response. We also identify an important role for pigmentation in the development of the mouse iPLR, with only a weak and transient response present in albino animals. Our results show that the iPLR in mice develops unexpectedly late and are consistent with a role for rods and pigmentation in the development of this response in mice. The enhancement of the iPLR in aged degenerate mice was extremely surprising but may have relevance to behavioral observations in mice and patients with retinitis pigmentosa

    Influence of health literacy on maintenance of exclusive breastfeeding at 6 months postpartum: a multicentre study

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    Background: International organizations recommend initiating breastfeeding within the first hour of life and maintaining exclusive breastfeeding for the first 6 months. However, worldwide rates of exclusive breastfeeding for 6-month-old infants is far from meeting the goal proposed by the World Health Organization, which is to reach a minimum of 50% of infants. Education is one of the factors affecting the initiation and continuation of breastfeeding, and incidentally, it is also related to lower health literacy. This study explored the influence of health literacy on maintenance of exclusive breastfeeding at 6 months postpartum. Methods: A longitudinal multicenter study with 343 women were recruited between January 2019 and January 2020. The first questionnaire was held during the puerperium (24–48 h) with mothers practicing exclusive breastfeeding, with whom 6-month postpartum breastfeeding follow-up was performed. Socio-demographic, clinical and obstetric variables were collected. Breastfeeding efficiency was assessed using the LATCH breastfeeding assessment tool. The health literacy level was evaluated by the Newest Vital Sign screening tool. A multivariate logistic regression model was used to detect protective factors for early exclusive breastfeeding cessation. Results: One third of the women continued exclusive breastfeeding at 6 months postpartum. Approximately half the participants had a low or inadequate health literacy level. An adequate health literacy level, a high LATCH breastfeeding assessment tool score (>9 points) and being married were the protective factors against exclusive breastfeeding cessation at 6 months postpartum. Conclusion: Health literacy levels are closely related to maintaining exclusive breastfeeding and act as a protective factor against early cessation. A specific instrument is needed to measure the lack of “literacy in breastfeeding”, in order to verify the relationship between health literacy and maintenance of exclusive breastfeedin

    The effect of prenatal education classes on the birth expectations of Spanish women

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    Background: Maternity care has focused on lowering maternal and neonatal morbidity, though women's beliefs and expectations of care have been set aside. Women face childbirth with preconceived expectations, some of which could be expressed on their birth plan. The latter could beinfluenced by health professionals through prenatal education classes, though this has not been measured before. Antenatal classes have been argued against,since no resulting improvement in childbirth experience has been demonstrated, though some advantages may be seen: they favour communication and give time for expressing maternal expectations and beliefs. The present study evaluates the influence of prenatal educational classes led by midwives upon women birth preferences. Methods: A multicentre, observational, prospective study was carried out, measuring variables in pregnant women attending prenatal educational classes in different health centres within the health districts in Valencia (Spain) over the period January-October 2012. Birth plan preferences were compared prior to and upon completion of the classes. Results: A total of 212 eligible pregnant women (78.3% nulliparous) with an average age of 31.39±4.0 years consented to participate in the study. There were significant differences in birth plan preferences prior to and upon completion of the prenatal classes. Three items showed an increase between the initial session and the end of the intervention: the ability to push spontaneously, episiotomy avoidance, and early breastfeeding. An adjusted general linear model was used to compare pre-post results in relation to sociodemographic and obstetric variables. Discussion: The changes in birth plans could suggest that prenatal educational classes exert an influence upon maternal birth preferences

    Effect of early skin-to-skin mother-infant contact in the maintenance of exclusive breastfeeding

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    Background: Breastfeeding has been shown to result in extensive physical and psychological benefits for both the mother and the newborn. However, the rate and duration of exclusive breastfeeding (EBF) remains low worldwide. Mother–infant skin-to-skin contact (SSC) immediately after birth has demonstrated results that support the argument for breastfeeding continuation. Research aim: This study aimed to investigate the prevalence of EBF 3 months postpartum and the effect of early SSC in maintaining optimal EBF practices for mothers and their healthy newborns. Methods: We conducted an observational, retrospective study in Spain from 2013 to 2015. Pregnant women were interviewed immediately postpartum and again at 3 months postpartum regarding variables associated with breastfeeding initiation and continuation. Results: There were 1,071 women recruited. Early SSC was performed in 92% of vaginal births but only 57% of urgent cesarean births. Of women breastfeeding at discharge, 69.5% performed SSC with their newborn. We found that 68.6% of women were exclusively breastfeeding by discharge and 46.7% by 3 months postpartum. Type of feeding at discharge, country of origin, and parity were found to be associated with each other (p = .003, p = .001, respectively). Early SSC was also significantly associated with type of feeding at discharge, 1 month, 2 months, and 3 months postpartum (p < .001). Hypogalactia (19.8%) was the most frequently reported factor for breastfeeding discontinuation. Conclusion: Breastfeeding promotion interventions are likely to improve breastfeeding rates at 3 months postpartum. Social and economic factors should be taken into account when such programs are planned to be implemented
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