Lactation Advice through Texting Can Help: An Analysis of Intensity of Engagement via Two-Way Text Messaging.

Rates of breastfeeding initiation and duration among women who attend the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) are dramatically lower than nonparticipants. Innovative solutions are needed to improve breastfeeding rates in this population. The Lactation Advice through Texting Can Help (LATCH) study was one such approach, designed to augment and reinforce the WIC breastfeeding peer counseling process. The purpose of the present study was to examine engagement via two-way text messaging in a sample of women attending the WIC breastfeeding peer counseling program and enrolled in LATCH. The objectives were to: (1) describe text message engagement in the context of LATCH; and (2) assess the association between engagement variables and exclusive breastfeeding status. Text messaging data were first coded qualitatively by two independent researchers and engagement variables created. An analysis of engagement was conducted using descriptive statistics for normally distributed data and binary logistic regression. In the multivariable model, intensity of engagement during the first 2 weeks post partum was the single strongest predictor of exclusive breastfeeding status. LATCH is an innovative intervention designed to enhance the capacity of breastfeeding peer counselors and holds much potential for improving exclusive breastfeeding rates in this population.

Estrogen receptor-positive mammary tumorigenesis in TGFalpha transgenic mice progresses with progesterone receptor loss.

We characterized the novel NRL-transforming growth factor alpha (NRL-TGFalpha) transgenic mouse model in which growth factor - steroid receptor interactions were explored. The NRL promoter directs transgene expression to mammary ductal and alveolar cells and is nonresponsive to estrogen manipulations in vitro and in vivo. NRL-TGFalpha mice acquire proliferative hyperplasias as well as cystic and solid tumors. Quantitative transcript analysis revealed a progressive decrease in estrogen receptor alpha (ER) and progesterone receptor (PR) mRNA levels with tumorigenesis. However, ER protein was evident in all lesion types and in surrounding stromal cells using immunohistochemistry. PR protein was identified in normal epithelial cells and in very few cells of small epithelial hyperplasias, but never in stromal or tumor cells. Prophylactic ovariectomy significantly delayed tumor development and decreased incidence. Finally, while heterozygous (+/-) p53 mice did not acquire mammary lesions, p53+/- mice carrying the NRL-TGFalpha transgene developed ER negative/PR negative undifferentiated carcinomas. These data demonstrate that unregulated TGFalpha expression in the mammary gland leads to oncogenesis that is dependent on ovarian steroids early in tumorigenesis. Resulting tumors resemble a clinical phenotype of ER+/PR-, and when combined with a heterozygous p53 genotype, ER-/PR-.

Obesity and weight misperception among adults in the Eastern Caribbean Health Outcomes Research Network (ECHORN) Cohort Study.

OBJECTIVE: Prior studies have suggested that weight misperception - underestimating one's actual weight - may be associated with reduced engagement in weight loss programmes, decreasing the success of initiatives to address obesity and obesity-related diseases. The purpose of this study was to examine the factors associated with weight misperception among Eastern Caribbean adults and its influence on engagement in weight control behaviour. METHODS: Data from the Eastern Caribbean Health Outcomes Research Network (ECHORN) Cohort Study were analysed (adults aged 40 and older, residing in the US Virgin Islands, Puerto Rico, Barbados and Trinidad). Weight misperception is defined as participants who under-assess their weight measured by body mass index (BMI). Multivariable logistic regression (n = 1,803 participants) was used to examine the association of weight misperception with BMI category, age, gender, education, history of non-communicable disease and attempt to lose weight. RESULTS: Weight misperception was common, with 54% of overweight (BMI 25-29 kg m-2), and 23% of obese class I (BMI 30-34.9 kg m-2) participants under-assessing their actual weight. Participants with higher levels of education, versus lower, had decreased odds of weight misperception (OR 0.5, p < 0.001). There were no significantly reduced odds of weight misperception in women versus men (OR 1.13, p = 0.367) or in individuals with history of diabetes versus none (OR 0.88, p = 0.418). Participants with weight misperception had 85% (p < 0.0001) lower odds of attempting weight loss than those with accurate weight perception. CONCLUSION: Weight misperception is common among adults with overweight and obesity in the Eastern Caribbean and is associated with lower likelihood of attempting weight loss. Obesity interventions, targeting similar populations, should incorporate approaches for addressing weight misperception to achieve measurable success.

An assessment of the social cognitive predictors of exclusive breastfeeding behavior using the Health Action Process Approach.

RATIONALE: In the United States rates of exclusive breastfeeding duration remain exceedingly low. Exclusive breastfeeding is a complex learned behavior that is influenced by social cognitive, interpersonal, and structural factors. Interventions are needed that address factors at multiple levels of the social-ecological model. This study was designed to examine the social cognitive predictors of exclusive breastfeeding behavior in a sample of low-income women attending the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) breastfeeding peer counseling program and enrolled in the Lactation Advice Through Texting Can Help (LATCH) study. OBJECTIVES: The objectives were to examine whether: (1) the theoretical model, the Health Action Process Approach (HAPA), fit the data well; (2) planning mediated the effect of intentions and maintenance self-efficacy on exclusive breastfeeding; and (3) recovery self-efficacy mediated the association between maintenance self-efficacy and exclusive breastfeeding behavior. METHODS: Outcome expectancies, action self-efficacy and intentions were assessed prenatally at baseline in N = 119 participants. Maintenance self-efficacy, planning, recovery self-efficacy and breastfeeding behavior were measured at two weeks post partum. Structural equation modeling with mean and variance adjusted Weighted Least Squares estimation was used to examine the applicability of the HAPA model to the data. RESULTS: Phase specific self-efficacy and planning significantly predicted exclusive breastfeeding status. Planning and recovery self-efficacy mediated the association between maintenance self-efficacy and exclusive breastfeeding. Planning did not emerge as a mediator between intentions and behavior. CONCLUSION: These results demonstrate the utility of the HAPA model in predicting exclusive breastfeeding behavior among low-income women attending WIC. LATCH is a theoretically sound text messaging intervention that can be used to augment and reinforce the WIC breastfeeding peer counseling process.

Casein kinase I is regulated by phosphatidylinositol 4,5-bisphosphate in native membranes.

Casein kinase I activity is present in cells as a cytosolic and a membrane-bound enzyme. Previously, the erythroid membrane-bound casein kinase I was shown to associate with purified integral membrane proteins; this association and protein kinase activity was regulated by phosphatidylinositol 4,5-bisphosphate (PIP2) (Bazenet, C.E., Brockman, J.L., Lewis, D., Chan, C., and Anderson, R.A. (1990) J. Biol. Chem. 265, 7369-7376). Here we show that both the membrane-bound and the cytosolic casein kinase interact with native membranes and that this interaction is regulated by the membrane content of PIP2. On native membranes, casein kinase I activity is potently inhibited by small increases (10-20%) in the membrane content of either exogenously added or intrinsic PIP2. However, the majority of the intrinsic content of PIP2 in isolated membranes does not inhibit casein kinase, suggesting that this PIP2 is not accessible. Regulation of the casein kinases on membranes is sensitive to detergents and to chymotrypsin treatment of membranes.

Prolactin receptor heterogeneity: processing and signalling of the long and short isoforms during development.

During development, the fetus is exposed to prolactin activity from the placenta, as well as from the developing fetal pituitary. Distinct prolactin receptor isoforms, having different cytoplasmic domains generated by alternative splicing, are expressed as development proceeds at different levels in different organs. The "long" receptors are able to mediate transduction of all signals examined, in contrast with the "short" isoforms, whose truncated cytoplasmic domains are able to mediate a much smaller repertoire of signals and can act as dominant negatives. Our studies demonstrate that, although these forms share internalization mechanisms, the long form is internalized faster, resulting in more rapid down-regulation of this form. In order to examine the mechanisms by which prolactin may exert trophic effects on its target tissues during development, we have examined the signalling pathways through which prolactin binding to the long receptor regulates the transcription of cyclin D1. Our studies reveal the importance of the JAK/STAT (Janus kinase/signal transduction and activators of transcription) pathway, and the complexity of prolactin signalling to this promoter.

Erythroid membrane-bound protein kinase binds to a membrane component and is regulated by phosphatidylinositol 4,5-bisphosphate.

In the erythrocyte, a membrane-bound serine/threonine protein kinase (a casein kinase) has been shown to phosphorylate a number of membrane proteins, modulating their function. Here we report that the membrane-bound protein kinase binds to membranes by an association with a minor membrane component contained in preparations of glycophorin (possibly a minor glycophorin). The binding of the kinase to glycophorins does not significantly modify kinase activity. However, upon binding, the kinase activity is potently inhibited by phosphatidylinositol 4,5-bisphosphate, and the affinity of the kinase for the glycophorins is increased. Other phospholipids or polyanions such as inositol 1,4,5-trisphosphate or 2,3-diphosphoglycerate do not affect protein kinase activity when the kinase is bound to membranes but do inhibit the solubilized membrane-bound kinase. In the erythrocyte, there is a cytosolic form of the casein kinase which is very similar, having the same molecular weight and substrate specificity as the membrane-bound casein kinase. The cytosolic casein kinase is inhibited by 2,3-diphosphoglycerate but much less so by glycophorin preparations containing phosphoinositol 4,5-bisphosphate. When the sequences of both casein kinases were compared by two-dimensional peptide mapping, it was found that the two kinases were very similar but not identical.

Cell cycle-dependent localization of casein kinase I to mitotic spindles.

Casein kinase I (CKI) is a class of protein kinases ubiquitous to all eukaryotic cells. Recently, cDNA clones encoding several bovine CKI isoforms have been sequenced that show high sequence identity to the HRR25 gene product of the budding yeast Saccharomyces cerevisiae; HRR25 is required for normal cellular growth, nuclear segregation, DNA repair, and meiosis. We have raised polyclonal antibodies to a human erythroid 34-kDa CKI and have sequenced a portion of this kinase. The amino acid sequence identifies the CKI as the alpha-CKI isoform, which is 62% identical to the HRR25 protein kinase. By use of immunofluorescence, the alpha-CKI has been localized to vesicular cytosolic structures and to the centrosome in interphase cells. As cells progress into mitosis, centrospheric staining increases and, in mitosis, alpha-CKI associates with kinetochore fibers. This localization suggests that alpha-CKI, like HRR25, plays a role in the segregation of chromosomes during mitosis and may be cell cycle-regulated both in humans and in yeast.

The human erythrocyte contains two forms of phosphatidylinositol-4-phosphate 5-kinase which are differentially active toward membranes.

A human erythrocyte cytosolic phosphatidylinositol-4-phosphate 5-kinase (PIP kinase) and a membrane-bound PIP kinase have been purified by phosphocellulose chromatography. Fractionation of the membrane-bound PIP kinase activities by phosphocellulose separated activity into two peaks, which eluted at 0.6 M NaCl (type I PIP kinase) and 1.0 M NaCl (type II PIP kinase). The cytosolic PIP kinase and the membrane-bound type II PIP kinase are 53 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, have indistinguishable 125I-peptide maps, and are immunochemically indistinguishable, suggesting that they are sequence identical. Antibodies raised to the cytosolic PIP kinase inhibit activity of both the membrane-bound type II and the cytosolic PIP kinases. The type I PIP kinase appears to be distinct from the cytosolic and membrane-bound type II PIP kinase; it is not immunocross-reactive, and antibodies toward type II PIP kinases do not inhibit type I PIP kinase. Further, membrane-bound type II PIP kinase can be removed from type I PIP kinase without loss of activity. Functional characterization of the PIP kinases demonstrates that the type I kinase has a 10-fold lower Km for PIP and a 5-fold higher Km for ATP compared with the type II enzymes. The type I and type II (membrane-bound or cytosolic) PIP kinases are modulated differentially by spermine and heparin. Finally, the type I PIP kinase phosphorylates intrinsic PIP on isolated erythrocyte membranes, whereas the type II PIP kinases have no activity toward native membranes.