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

Harrison's Principles of Internal Medicine

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

The Self-Organizing Map

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.

http://www-math.mit.edu/~edelman/publications/geometry_of_algorithms.pdf

The Geometry of Algorithms with Orthogonality Constraints

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。

Sarcoidosis

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.

Type 2 diabetes mellitus.

Background The association between acne keloidalis nuchae (AKN) and thyroid diseases is yet to be investigated. Objective To evaluate the risk of developing hypothyroidism and hyperthyroidism among patients with AKN and to characterize the patients who have AKN and thyroid comorbidities. Methods A population-based cohort study was conducted comparing AKN patients (n = 2,677) with age-, gender-, and ethnicity-matched control subjects (n = 13,190) with regard to incident cases of hypothyroidism and hyperthyroidism. Adjusted hazard ratios (HRs) were estimated by Cox regression analysis. Results The incidence rates of hypothyroidism among patients with AKN and controls were estimated at 2.15 (95% CI, 1.49-2.99) and 0.82 (95% CI, 0.66-1.00) cases/1000 person-years, respectively. The crude risk of developing incident hypothyroidism was 1.85-fold greater in patients with AKN (HR, 1.85; 95% CI, 1.24-2.78; P = 0.003). The elevated risk persisted following the adjustment for putative confounders (adjusted HR, 1.72; 95% CI, 1.03-2.89; P = 0.040). The risk of hyperthyroidism was comparable in patients with AKN and controls both in the crude (HR, 1.55; 95% CI, 0.57-4.22) and adjusted (adjusted HR, 1.92; 95% CI, 0.59-6.21) analyses. Patients with coexistent AKN and thyroid diseases were significantly older at the onset of AKN, had more prominent female preponderance, and had a higher burden of comorbidity. Conclusions Patients with AKN are at an increased risk of hypothyroidism. Screening for hypothyroidism should be considered in AKN patients with a compatible clinical picture.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/ijd.15331

Acne keloidalis nuchae and thyroid diseases: a population-based cohort study.

BACKGROUND Dermatomyositis (DM) and polymyositis (PM) are two rare autoimmune disorders occasionally described with dysthyroidism; however, no solid evidence still proves such an association. AIM To evaluate the prevalence of dysthyroidism among DM/PM patients. DESIGN AND SETTING A nation-wide case-control study was conducted. METHODS From the Clalit Health Services health records database, we extracted 2085 (DM = 1475 (70.7%), PM = 610 (29.3%)) PM/DM cases and 10 193 sex-age matched controls in the period 2000-2018. Both univariate and multivariate analyses were performed to evaluate the link dysthyroidism and PM/DM. Survival analysis was also performed. RESULTS The rate of hyperthyroidism was significantly (P = .0097) higher in cases (n = 40, 1.9%) with respect to controls (n = 123, 1.2%). Similarly, the rate of hypothyroidism was significantly (P < .0001) associated with cases (n = 234, 11.2%) when compared to controls (n = 853, 8.4%). At the multivariate logistic regression analysis, both DM (OR 1.31 [95%CI 1.07-1.60], P = .0087) and PM (OR 1.54 [95%CI 1.21-1.95], P = .004) were significantly associated with hypothyroidism, whereas DM (OR 1.70 [95%CI 1.10-2.61], P = .0165) but not PM (OR 1.45 [0.83-2.55], P = .1947) was found to be associated with hyperthyroidism. Subjects with PM and positive for anti-Sjogren's syndrome-related antigen A (SSA) auto-antibody displayed a significant risk of developing hyperthyroidism (OR 5.85 [95%CI 1.02-33.74], P = .0480), whereas individuals with DM and positive for antinuclear antibody (ANA) had a higher risk of developing hyperthyroidism (OR 2.65 [95%CI 1.00-7.03], P = .0498). CONCLUSIONS Physicians treating PM/DM patients should consider screening for thyroid dysfunction on a regular basis.

Arnon D. Cohen

Papers

Acne keloidalis nuchae and thyroid diseases: a population-based cohort study.

Dysthyroidism in dermato/polymyositis patients: a case‐control study