747 research outputs found

    Pregnancy postponement and childlessness leads to chronic hypervascularity of the breasts and cancer risk

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    Epidemiologists have established that women with small families, and particularly nulliparae, are prone to develop breast cancer later in life. We report that physiological mammary hypervascularity may be an intermediate reason against the background that breast-core vascularity is normal in pregnancy but pathological in the vascularisation of cancer. We examined breast ‘core’ vascularity in nulliparae during their potential reproductive life and in parous women after their last birth but before their menopause. Fifty clinically normal pre-menopausal non-pregnant women (100 breasts) were studied daily for one ‘luteal positive’ menstrual cycle. Their parity history varied from zero to five babies. Under controlled domestic conditions each wore a special electronic thermometric bra to automatically record breast ‘core’ temperature changes as a measure of mammary tissue blood flow. In the nulliparae there was a rise of breast vascularity throughout reproductive life. In the parous women, a year or so after each birth, breast vascularity was reset at a lower level than before the pregnancy; thereafter, as in nulliparae, there was progressive increase in mammary vascularity until the menopause

    Pregnancy-related factors and the risk of breast carcinoma in situ and invasive breast cancer among postmenopausal women in the California Teachers Study cohort

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    Abstract Introduction Although pregnancy-related factors such as nulliparity and late age at first full-term pregnancy are well-established risk factors for invasive breast cancer, the roles of these factors in the natural history of breast cancer development remain unclear. Methods Among 52,464 postmenopausal women participating in the California Teachers Study (CTS), 624 were diagnosed with breast carcinoma in situ (CIS) and 2,828 with invasive breast cancer between 1995 and 2007. Multivariable Cox proportional hazards regression methods were used to estimate relative risks associated with parity, age at first full-term pregnancy, breastfeeding, nausea or vomiting during pregnancy, and preeclampsia. Results Compared with never-pregnant women, an increasing number of full-term pregnancies was associated with greater risk reduction for both breast CIS and invasive breast cancer (both P trend < 0.01). Women having four or more full-term pregnancies had a 31% lower breast CIS risk (RR = 0.69, 95% CI = 0.51 to 0.93) and 18% lower invasive breast cancer risk (RR = 0.82, 95% CI = 0.72 to 0.94). Parous women whose first full-term pregnancy occurred at age 35 years or later had a 118% greater risk for breast CIS (RR = 2.18, 95% CI = 1.36 to 3.49) and 27% greater risk for invasive breast cancer (RR = 1.27, 95% CI = 0.99 to 1.65) than those whose first full-term pregnancy occurred before age 21 years. Furthermore, parity was negatively associated with the risk of estrogen receptor-positive (ER+) or ER+/progesterone receptor-positive (PR+) while age at first full-term pregnancy was positively associated with the risk of ER+ or ER+/PR+ invasive breast cancer. Neither of these factors was statistically significantly associated with the risk of ER-negative (ER-) or ER-/PR- invasive breast cancer, tests for heterogeneity between subtypes did not reach statistical significance. No clear associations were detected for other pregnancy-related factors. Conclusions These results provide some epidemiologic evidence that parity and age at first full-term pregnancy are involved in the development of breast cancer among postmenopausal women. The role of these factors in risk of in situ versus invasive, and hormone receptor-positive versus -negative breast cancer merits further exploration

    Pyroglutamate Abeta pathology in APP/PS1KI mice, sporadic and familial Alzheimer’s disease cases

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    The presence of AβpE3 (N-terminal truncated Aβ starting with pyroglutamate) in Alzheimer’s disease (AD) has received considerable attention since the discovery that this peptide represents a dominant fraction of Aβ peptides in senile plaques of AD brains. This was later confirmed by other reports investigating AD and Down’s syndrome postmortem brain tissue. Importantly, AβpE3 has a higher aggregation propensity, and stability, and shows an increased toxicity compared to full-length Aβ. We have recently shown that intraneuronal accumulation of AβpE3 peptides induces a severe neuron loss and an associated neurological phenotype in the TBA2 mouse model for AD. Given the increasing interest in AβpE3, we have generated two novel monoclonal antibodies which were characterized as highly specific for AβpE3 peptides and herein used to analyze plaque deposition in APP/PS1KI mice, an AD model with severe neuron loss and learning deficits. This was compared with the plaque pattern present in brain tissue from sporadic and familial AD cases. Abundant plaques positive for AβpE3 were present in patients with sporadic AD and familial AD including those carrying mutations in APP (arctic and Swedish) and PS1. Interestingly, in APP/PS1KI mice we observed a continuous increase in AβpE3 plaque load with increasing age, while the density for Aβ1-x plaques declined with aging. We therefore assume that, in particular, the peptides starting with position 1 of Aβ are N-truncated as disease progresses, and that, AβpE3 positive plaques are resistant to age-dependent degradation likely due to their high stability and propensity to aggregate

    Dental management considerations for the patient with an acquired coagulopathy. Part 1: Coagulopathies from systemic disease

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    Current teaching suggests that many patients are at risk for prolonged bleeding during and following invasive dental procedures, due to an acquired coagulopathy from systemic disease and/or from medications. However, treatment standards for these patients often are the result of long-standing dogma with little or no scientific basis. The medical history is critical for the identification of patients potentially at risk for prolonged bleeding from dental treatment. Some time-honoured laboratory tests have little or no use in community dental practice. Loss of functioning hepatic, renal, or bone marrow tissue predisposes to acquired coagulopathies through different mechanisms, but the relationship to oral haemostasis is poorly understood. Given the lack of established, science-based standards, proper dental management requires an understanding of certain principles of pathophysiology for these medical conditions and a few standard laboratory tests. Making changes in anticoagulant drug regimens are often unwarranted and/or expensive, and can put patients at far greater risk for morbidity and mortality than the unlikely outcome of postoperative bleeding. It should be recognised that prolonged bleeding is a rare event following invasive dental procedures, and therefore the vast majority of patients with suspected acquired coagulopathies are best managed in the community practice setting

    Regulation of mammary gland branching morphogenesis by the extracellular matrix and its remodeling enzymes.

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    A considerable body of research indicates that mammary gland branching morphogenesis is dependent, in part, on the extracellular matrix (ECM), ECM-receptors, such as integrins and other ECM receptors, and ECM-degrading enzymes, including matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitors of metalloproteinases (TIMPs). There is some evidence that these ECM cues affect one or more of the following processes: cell survival, polarity, proliferation, differentiation, adhesion, and migration. Both three-dimensional culture models and genetic manipulations of the mouse mammary gland have been used to study the signaling pathways that affect these processes. However, the precise mechanisms of ECM-directed mammary morphogenesis are not well understood. Mammary morphogenesis involves epithelial 'invasion' of adipose tissue, a process akin to invasion by breast cancer cells, although the former is a highly regulated developmental process. How these morphogenic pathways are integrated in the normal gland and how they become dysregulated and subverted in the progression of breast cancer also remain largely unanswered questions

    Intraneuronal pyroglutamate-Abeta 3–42 triggers neurodegeneration and lethal neurological deficits in a transgenic mouse model

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    It is well established that only a fraction of Aβ peptides in the brain of Alzheimer’s disease (AD) patients start with N-terminal aspartate (Aβ1D) which is generated by proteolytic processing of amyloid precursor protein (APP) by BACE. N-terminally truncated and pyroglutamate modified Aβ starting at position 3 and ending with amino acid 42 [Aβ3(pE)–42] have been previously shown to represent a major species in the brain of AD patients. When compared with Aβ1–42, this peptide has stronger aggregation propensity and increased toxicity in vitro. Although it is unknown which peptidases remove the first two N-terminal amino acids, the cyclization of Aβ at N-terminal glutamate can be catalyzed in vitro. Here, we show that Aβ3(pE)–42 induces neurodegeneration and concomitant neurological deficits in a novel mouse model (TBA2 transgenic mice). Although TBA2 transgenic mice exhibit a strong neuronal expression of Aβ3–42 predominantly in hippocampus and cerebellum, few plaques were found in the cortex, cerebellum, brain stem and thalamus. The levels of converted Aβ3(pE)-42 in TBA2 mice were comparable to the APP/PS1KI mouse model with robust neuron loss and associated behavioral deficits. Eight weeks after birth TBA2 mice developed massive neurological impairments together with abundant loss of Purkinje cells. Although the TBA2 model lacks important AD-typical neuropathological features like tangles and hippocampal degeneration, it clearly demonstrates that intraneuronal Aβ3(pE)–42 is neurotoxic in vivo

    Dehydroepiandrosterone inhibits the progression phase of mammary carcinogenesis by inducing cellular senescence via a p16-dependent but p53-independent mechanism

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    INTRODUCTION: Dehydroepiandrosterone (DHEA), an adrenal 17-ketosteroid, is a precursor of testosterone and 17β-estradiol. Studies have shown that DHEA inhibits carcinogenesis in mammary gland and prostate as well as other organs, a process that is not hormone dependent. Little is known about the molecular mechanisms of DHEA-mediated inhibition of the neoplastic process. Here we examine whether DHEA and its analog DHEA 8354 can suppress the progression of hyperplastic and premalignant (carcinoma in situ) lesions in mammary gland toward malignant tumors and the cellular mechanisms involved. METHODS: Rats were treated with N-nitroso-N-methylurea and allowed to develop mammary hyperplastic and premalignant lesions with a maximum frequency 6 weeks after carcinogen administration. The animals were then given DHEA or DHEA 8354 in the diet at 125 or 1,000 mg/kg diet for 6 weeks. The effect of these agents on induction of apoptosis, senescence, cell proliferation, tumor burden and various effectors of cellular signaling were determined. RESULTS: Both agents induced a dose-dependent decrease in tumor multiplicity and in tumor burden. In addition they induced a senescent phenotype in tumor cells, inhibited cell proliferation and increased the number of apoptotic cells. The DHEA-induced cellular effects were associated with increased expression of p16 and p21, but not p53 expression, implicating a p53-independent mechanism in their action. CONCLUSION: We provide evidence that DHEA and DHEA 8354 can suppress mammary carcinogenesis by altering various cellular functions, inducing cellular senescence, in tumor cells with the potential involvement of p16 and p21 in mediating these effects

    Lack of Protection following Passive Transfer of Polyclonal Highly Functional Low-Dose Non-Neutralizing Antibodies

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    Recent immune correlates analysis from the RV144 vaccine trial has renewed interest in the role of non-neutralizing antibodies in mediating protection from infection. While neutralizing antibodies have proven difficult to induce through vaccination, extra-neutralizing antibodies, such as those that mediate antibody-dependent cellular cytotoxicity (ADCC), are associated with long-term control of infection. However, while several non-neutralizing monoclonal antibodies have been tested for their protective efficacy in vivo, no studies to date have tested the protective activity of naturally produced polyclonal antibodies from individuals harboring potent ADCC activity. Because ADCC-inducing antibodies are highly enriched in elite controllers (EC), we passively transferred highly functional non-neutralizing polyclonal antibodies, purified from an EC, to assess the potential impact of polyclonal non-neutralizing antibodies on a stringent SHIV-SF162P3 challenge in rhesus monkeys. Passive transfer of a low-dose of ADCC inducing antibodies did not protect from infection following SHIV-SF162P3 challenge. Passively administered antibody titers and gp120-specific, but not gp41-specific, ADCC and antibody induced phagocytosis (ADCP) were detected in the majority of the monkeys, but did not correlate with post infection viral control. Thus these data raise the possibility that gp120-specific ADCC activity alone may not be sufficient to control viremia post infection but that other specificities or Fc-effector profiles, alone or in combination, may have an impact on viral control and should be tested in future passive transfer experiments
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