Polymorphisms in FcgammaRIIIA (CD16) receptor expression are associated with clinical response to rituximab in Waldenstr?m's macroglobulinemia.

PURPOSE: Rituximab is an important therapeutic for Waldenstrom's macroglobulinemia (WM). Polymorphisms in FcgammaRIIIA (CD16) receptor expression modulate human immunoglobulin G1 binding and antibody-dependent cell-mediated cytotoxicity, and may therefore influence responses to rituximab. PATIENTS AND METHODS: Sequence analysis of the entire coding region of FcgammaRIIIA was undertaken in 58 patients with WM whose outcomes after rituximab were known. RESULTS: Variations in five codons of FcgammaRIIIA were identified. Two were commonly observed (FcgammaRIIIA-48 and FcgammaRIIIA-158) and predicted for amino acid polymorphisms at FcgammaRIIIA-48: leucine/leucine (L/L), leucine/arginine (L/R), and leucine/histidine (L/H). Polymorphisms at FcgammaRIIIA-158 were phenylalanine/phenylalanine (F/F), phenylalanine/valine (F/V), and valine/valine (V/V). A clear linkage between these polymorphisms was detected and all patients with FcgammaRIIIA-158F/F were always FcgammaRIIIA-48L/L, and patients with either FcgammaRIIIA-L/R or -L/H always expressed at least one valine at FcgammaRIIIA-158 (P < or = .001). The response trend was higher for patients with FcgammaRIIIA-48L/H (38.5%) versus -48L/R (25.0%) and LL (22.0%), and was significantly higher for patients with FcgammaRIIIA-158V/V (40.0%) and -V/F (35%) versus -158F/F (9.0%; P = .030). Responses for patients with FcgammaRIIIA-48L/L were higher when at least one valine was present at FcgammaRIIIA-158 (P = .057), thereby supporting a primary role for FcgammaRIIIA-158 polymorphisms in predicting rituximab responses. With a median follow-up of 13 months, no significant differences in the median time to progression and progression-free survival were observed when patients were grouped according to their FcgammaRIIIA-48 and -158 polymorphisms. CONCLUSION: The results of these studies therefore support a predictive role for FcgammaRIIIA-158 polymorphisms and responses to rituximab in WM.     

Treatment failures secondary to drug interactions with divalent cations and fluoroquinolone

We observed four cases of therapeutic failures while patients were simultaneously taking medications that contained divalent cations and oral fluoroquinolones. Patients improved after conversion to the intravenous formulation of the same antibiotics, proper spacing of the divalent cation, or conversion to a different antibiotic class. Patients prescribed oral fluoroquinolones should receive instructions on proper separations of these antibiotics with divalent cations. Health care professionals should be cognizant of these interactions and educated on their potential deleterious effect.     

Decreased insulin responsiveness of glucose uptake in cultured human skeletal muscle cells from insulin-resistant nondiabetic relatives of type 2 diabetic families

To investigate the contribution of inherited biochemical defects to the peripheral insulin resistance of type 2 diabetes, we studied cultured skeletal muscle from 10 insulin-resistant nondiabetic first-degree relatives of type 2 diabetic families and 6 control subjects. Insulin stimulation of glucose uptake and glycogen synthesis was maximal in myoblasts. Insulin-stimulated glucose uptake (fold-stimulation over basal uptake) was decreased in relative compared with control myoblasts at 0.001 micromol/l (0.93 +/- 0.05 [mean +/- SE] vs. 1.15 +/- 0.06, P < 0.05) and 0.1 micromol/l (1.38 +/- 0.10 vs. 1.69 +/- 0.08, P = 0.025) insulin. Insulin responsiveness was markedly impaired in 5 of the relative myoblast cultures, and in 4 of these, there was an associated increase in basal glucose uptake (76.7 +/- 7.0 vs. 47.4 +/- 5.5 pmol x min(-1) x mg(-1) protein, relative vs. control; P < 0.02). Expression of insulin receptor substrate 1, phosphatidylinositol 3-kinase, protein kinase B, and glycogen synthase was normal in the relative cultures with impaired insulin responsiveness. Glycogen synthesis was also normal in the relative cultures. We conclude that the persistence of impaired insulin responsiveness in some of the relative cultures supports the role of inherited factors in the insulin resistance of type 2 diabetes and that the association with increased basal glucose uptake suggests that the 2 abnormalities may be linked.     

PSTPIP1‐associated myeloid‐related proteinemia inflammatory syndrome: A rare cause of childhood neutropenia associated with systemic inflammation and hyperzincemia

Neutropenia in pediatric patients can be due to a variety of disorders. We describe two patients who underwent extensive evaluation over many years for arthralgias and moderate neutropenia of unclear etiology. Genetic testing identified a pathogenic variant in PSTPIP1 (proline‐serine‐threonine phosphatase‐interacting protein 1) in both patients. Markedly elevated inflammatory markers and zinc levels confirmed the rare diagnosis of PSTPIP1‐associated myeloid‐related proteinemia inflammatory (PAMI) syndrome, tailoring treatment. Neutropenia is common in patients with PAMI syndrome. Unique mutations seen in PAMI syndrome may account for the specific phenotypic features of this disorder.     

Development and pretesting of “Becoming Breastfeeding Friendly”: Empowering governments for global scaling up of breastfeeding programmes

Scaling up breastfeeding programmes has not been highly prioritized despite overwhelming evidence that breastfeeding benefits the health of mothers and children. Lack of evidence‐based tools for scaling up may deter countries from prioritizing breastfeeding. To fill this gap, Becoming Breastfeeding Friendly (BBF) was developed to guide countries in effectively scaling up programmes to protect, promote, and support breastfeeding. BBF includes an evidence‐based toolbox that consists of a BBF Index, case studies, and a 5‐meeting process. These three interrelated components enable countries to assess their breastfeeding scaling up environment, identify gaps, propose policy recommendations, develop a scaling up plan, and track progress. The toolbox was developed based on current evidence and expert guidance from a Technical Advisory Group, which was composed of global breastfeeding and metric experts with experience in the scaling up of health and nutrition programmes in low‐, middle‐, and high‐income countries. The BBF toolbox required a step‐by‐step iterative approach to describe and systematize each component, thus an operational manual was developed. The BBF toolbox and BBF operational manual underwent intensive pretesting in two countries, Ghana and Mexico, resulting in the modification of each component plus the operational manual. Pretesting continues in six additional countries demonstrating that BBF is a robust and dynamic multi‐sectoral process that, with relatively minor adaptations, can be successfully implemented in countries across world regions.     

Inhibition of Neu-Induced Mammary Carcinogenesis in Transgenic Mice Expressing ERΔ3, a Dominant Negative Estrogen Receptor α Variant

The estrogen receptor ?? (ER??) splicing variant with an in-frame deletion of exon 3 (ER??3) is frequently expressed in the normal breast, but its influence on tumorigenesis has not been explored. In vitro, ER??3 has dominant negative activity, suggesting it may suppress estrogen stimulation in the breast. ER??3 may inhibit classical signaling on estrogen response element (ERE)-regulated genes as well as activate non-classical pathways at Sp1 and AP-1 sites. Transgenic mice were developed that express mouse ER??3 in all tissues examined, including the mammary gland. To investigate if ER??3 expression affects tumorigenesis, ER??3 mice were crossbred with MMTV-Neu mice. Mammary tumor onset was significantly delayed in ER??3/Neu versus MMTV-Neu females and metastatic incidence and burden was significantly reduced. Consequently, ER??3 expression suppressed tumor development and metastasis in this aggressive model of HER2/Neu-positive breast cancer. To determine if ER ligands with anticancer activity may augment ER??3 protection, the bitransgenic mice were treated with tamoxifen and soy isoflavones starting at age 2?months. Soy protein with isoflavones (181?mg/1,800?kcal) did not affect tumor development in MMTV-Neu or ER??3/Neu mice; however, metastatic progression was not inhibited in soy-treated ER??3/Neu mice, as it was in untreated ER??3/Neu mice. In contrast, tamoxifen (20?mg/1,800?kcal) significantly enhanced tumor prevention in ER??3/Neu versus MMTV-Neu mice (98?% vs. 81?% tumor free). The results in ER??3/Neu mice demonstrate that ER??3 influences estrogen-dependent mammary carcinogenesis and, thus, may be protective in women expressing ER??3 in the breast. However, exposure to different estrogens may augment or block its beneficial effects.     

Friendship 2.0: Adolescents' experiences of belonging and self-disclosure online

This study explores the role that digital media technologies play in adolescents' experiences of friendship and identity. The author draws on findings from in-depth interviews with 32 adolescents (15 girls, 17 boys) ages 13–18 (M = 15.5 years) attending one of seven secondary schools in Bermuda. The adolescents were asked to describe the nature of their online exchanges with friends and the value they ascribe to these conversations. A thematic analysis of their responses revealed that online peer communications promote adolescents' sense of belonging and self-disclosure, two important peer processes that support identity development during adolescence. At the same time, the unique features of computer-mediated communication shape adolescents' experiences of these processes in distinct ways. Gender and age differences show that adolescents' online peer communications are not uniform; the characteristics that distinguish adolescents offline also shape their online activities.