Arnon D. Cohen

Bio: Arnon D. Cohen is an academic researcher from Clalit Health Services. The author has contributed to research in topics: Population & Odds ratio. The author has an hindex of 41, co-authored 374 publications receiving 7913 citations. Previous affiliations of Arnon D. Cohen include University of Milan & University of Connecticut.

Reduced placental growth and hCG secretion in vitro induced by antiphospholipid antibodies but not by anti-Ro or anti-La: studies on sera from women with SLE/PAPS.

Abstract: Systemic lupus erythematosus (SLE) and primary anti-phospholipid syndrome (PAPS) are autoimmune diseases causing recurrent pregnancy loss. We hypothesized that anti-phospholipid antibodies (aPL), but not anti-Ro and anti-La antibodies, might have a role through direct placental damage. We cultured human placental explants in sera from women with SLE/PAPS with different antibodies. These sera were found to reduce placental growth and increase trophoblastic apoptosis. No effect was found on estradiol or progesterone secretion, but inhibition in betahCG secretion was detected. BetahCG was reduced in women with a history of recurrent pregnancy loss or thromboembolic events, and was also the most sensitive marker when examining the effects of specific antibodies. High titers of aPL were found to cause the largest reduction in betahCG. Anti-Ro and anti-La did not induce placental damage. A strong correlation was found between the rise in the number of different antibodies in the sera and the incidence of recurrent pregnancy loss, which was also accompanied by a decline in the betahCG levels. In conclusion, aPL, but not anti-Ro or anti-La, may cause placental damage in vitro. Thus betahCG levels might constitute a predictive marker for the risk of placental damage and pregnancy loss in women with SLE/PAPS.

Dermatofibrosarcoma protuberans appearing during pregnancy.

Abstract: Dermatofibrosarcoma protuberans is an uncommon skin tumor with a high potential for local recurrence if not adequately excised. There are only two reports in the literature describing dermatofibrosarcoma protuberans that enlarged considerably during pregnancy. On the other hand, the new development or enlargement of dermatofibromas in pregnancy is well documented. We present 2 additional patients in whom a dermatofibrosarcoma protuberans appeared and grew rapidly during pregnancy. Immunohistochemical studies were negative for estrogen and progesterone receptors. The possible pathophysiology and surgical management are presented and discussed.

The link between schizophrenia and hypothyroidism: a population-based study.

Abstract: Schizophrenia is considered to be of the severe psychiatric disorders characterized by chronic debilitating course marked with frequent relapses and high clinical and financial burden. Aberrations of thyroid hormone levels have been documented in several psychiatric conditions including bipolar disease. The aim of this study is to provide insight into whether an association exists between hypothyroidism and schizophrenia. A population-based cross-sectional study was conducted using data retrieved from the largest medical records database in Israel, the Clalit Health Services (CHS). Patients were defined as having hypothyroidism or schizophrenia when there was at least one such documented diagnosis in their medical records. The proportion of schizophrenia was compared between hypothyroid and age- and sex frequency-matched healthy controls. A logistic regression model was used to estimate the association between psychiatric manifestations and hypothyroidism in a multivariate analysis adjusted for age, gender, and smoking status. The study included 40,843 patients with hypothyroidism and 40,918 age- and sex frequency-matched controls. The proportion of schizophrenia in hypothyroid patients was higher than that in controls (2.01% vs. 1.25%, respectively, p < 0.0001). Multivariate logistic regression demonstrated a robust independent association between hypothyroidism and schizophrenia (OR 1.62, p ≤ 0.001). Our study confirms a higher proportion of hypothyroidism among patients with schizophrenia. The awareness of such interrelation should drive physicians treating patients with schizophrenia to consider screening for hypothyroidism. Further studies are required to elucidate the underlying mechanism or the common denominator favoring the co-occurrence of schizophrenia and hypothyroidism.

Harrison's Principles of Internal Medicine

Abstract: The 11th edition of Harrison's Principles of Internal Medicine welcomes Anthony Fauci to its editorial staff, in addition to more than 85 new contributors. While the organization of the book is similar to previous editions, major emphasis has been placed on disorders that affect multiple organ systems. Important advances in genetics, immunology, and oncology are emphasized. Many chapters of the book have been rewritten and describe major advances in internal medicine. Subjects that received only a paragraph or two of attention in previous editions are now covered in entire chapters. Among the chapters that have been extensively revised are the chapters on infections in the compromised host, on skin rashes in infections, on many of the viral infections, including cytomegalovirus and Epstein-Barr virus, on sexually transmitted diseases, on diabetes mellitus, on disorders of bone and mineral metabolism, and on lymphadenopathy and splenomegaly. The major revisions in these chapters and many

The Self-Organizing Map

Abstract: An overview of the self-organizing map algorithm, on which the papers in this issue are based, is presented in this article.

The Geometry of Algorithms with Orthogonality Constraints

Abstract: In this paper we develop new Newton and conjugate gradient algorithms on the Grassmann and Stiefel manifolds. These manifolds represent the constraints that arise in such areas as the symmetric eigenvalue problem, nonlinear eigenvalue problems, electronic structures computations, and signal processing. In addition to the new algorithms, we show how the geometrical framework gives penetrating new insights allowing us to create, understand, and compare algorithms. The theory proposed here provides a taxonomy for numerical linear algebra algorithms that provide a top level mathematical view of previously unrelated algorithms. It is our hope that developers of new algorithms and perturbation theories will benefit from the theory, methods, and examples in this paper.

Sarcoidosis

Abstract: 结节病易误诊,据王洪武等~([1])收集国内18篇关于此病误诊的文献,误诊率高达63.2%,当然有误诊就会有误治,如孙永昌等~([2])报道26例结节病在影像学检查诊断的第一印象中拟诊结核5例,其中就有2例完成规范的抗结核治疗,为此应引起临床对本病诊治的重视。

Type 2 diabetes mellitus.

Abstract: Type 2 diabetes mellitus (T2DM) is an expanding global health problem, closely linked to the epidemic of obesity. Individuals with T2DM are at high risk for both microvascular complications (including retinopathy, nephropathy and neuropathy) and macrovascular complications (such as cardiovascular comorbidities), owing to hyperglycaemia and individual components of the insulin resistance (metabolic) syndrome. Environmental factors (for example, obesity, an unhealthy diet and physical inactivity) and genetic factors contribute to the multiple pathophysiological disturbances that are responsible for impaired glucose homeostasis in T2DM. Insulin resistance and impaired insulin secretion remain the core defects in T2DM, but at least six other pathophysiological abnormalities contribute to the dysregulation of glucose metabolism. The multiple pathogenetic disturbances present in T2DM dictate that multiple antidiabetic agents, used in combination, will be required to maintain normoglycaemia. The treatment must not only be effective and safe but also improve the quality of life. Several novel medications are in development, but the greatest need is for agents that enhance insulin sensitivity, halt the progressive pancreatic β-cell failure that is characteristic of T2DM and prevent or reverse the microvascular complications. For an illustrated summary of this Primer, visit: http://go.nature.com/V2eGfN.