In medical research data are often collected serially on subjects. The statistical analysis of such data is often inadequate in two ways: it may fail to settle clinically relevant questions and it may be statistically invalid. A commonly used method which compares groups at a series of time points, possibly with t tests, is flawed on both counts. There may, however, be a remedy, which takes the form of a two stage method that uses summary measures. In the first stage a suitable summary of the response in an individual, such as a rate of change or an area under a curve, is identified and calculated for each subject. In the second stage these summary measures are analysed by simple statistical techniques as though they were raw data. The method is statistically valid and likely to be more relevant to the study questions. If this method is borne in mind when the experiment is being planned it should promote studies with enough subjects and sufficient observations at critical times to enable useful conclusions to be drawn. Use of summary measures to analyse serial measurements, though not new, is potentially a useful and simple tool in medical research.

https://www.bmj.com/content/bmj/300/6719/230.full.pdf

Analysis of serial measurements in medical research.

OBJECTIVE\nTo develop a standardized nomenclature system for the neuropsychiatric syndromes of systemic lupus erythematosus (NPSLE).\n\n\nMETHODS\nAn international, multidisciplinary committee representing rheumatology, neurology, psychiatry, neuropsychology, and hematology developed case definitions, reporting standards, and diagnostic testing recommendations. Before and after the meeting, clinician committee members assigned diagnoses to sets of vignettes randomly generated from a pool of 108 NPSLE patients. To assess whether the nomenclature system improved diagnostic agreement, a consensus index was developed and pre- and postmeeting scores were compared by t-tests.\n\n\nRESULTS\nCase definitions including diagnostic criteria, important exclusions, and methods of ascertainment were developed for 19 NPSLE syndromes. Recommendations for standard reporting requirements, minimum laboratory evaluation, and imaging techniques were formulated. A short neuropsychological test battery for the diagnosis of cognitive deficits was proposed. In the postmeeting exercise, a statistically significant improvement in diagnostic agreement was observed.\n\n\nCONCLUSION\nThe American College of Rheumatology (ACR) Nomenclature for NPSLE provides case definitions for 19 neuropsychiatric syndromes seen in SLE, with reporting standards and recommendations for laboratory and imaging tests. It is intended to facilitate and enhance clinical research, particularly multicenter studies, and reporting. In clinical settings, consultation with other specialists may be required. It should be useful for didactic purposes but should not be used uncritically or as a substitute for a clinical diagnosis. The complete case definitions are available on the ACR World Wide Web site: http://www.rheumatology .org/ar/ar.html.

The American College of Rheumatology nomenclature and case definitions for neuropsychiatric lupus syndromes

Nearly 50 years ago, Chase published a review of hair cycling in which he detailed hair growth in the mouse and integrated hair biology with the biology of his day. In this review we have used Chas...

/pdf/controls-of-hair-follicle-cycling-2h0o2ckdy0.pdf

Controls of hair follicle cycling.

Hair has many useful biologic functions, including protection from the elements and dispersion of sweat-gland products (e.g., pheromones). It also has psychosocial importance in our society, and patients with hair loss (alopecia) (Table 1) or excessive hair growth often suffer tremendously. Not surprisingly, the demand for drugs that alter hair growth and appearance has led to a multibillion-dollar industry, yet few drugs that are effective for these purposes are available. However, recent progress in our understanding of the biology and pathology of hair follicles should lead to more effective therapies for disorders of hair growth. Structure and Function of Hair . . .

The biology of hair follicles.

This report provides a review of early and late effects of radiation in normal tissues and organs with respect to radiation protection. It was instigated following a recommendation in Publication 103 (ICRP, 2007), and it provides updated estimates of 'practical' threshold doses for tissue injury defined at the level of 1% incidence. Estimates are given for morbidity and mortality endpoints in all organ systems following acute, fractionated, or chronic exposure. The organ systems comprise the haematopoietic, immune, reproductive, circulatory, respiratory, musculoskeletal, endocrine, and nervous systems; the digestive and urinary tracts; the skin; and the eye. Particular attention is paid to circulatory disease and cataracts because of recent evidence of higher incidences of injury than expected after lower doses; hence, threshold doses appear to be lower than previously considered. This is largely because of the increasing incidences with increasing times after exposure. In the context of protection, it is the threshold doses for very long follow-up times that are the most relevant for workers and the public; for example, the atomic bomb survivors with 40-50years of follow-up. Radiotherapy data generally apply for shorter follow-up times because of competing causes of death in cancer patients, and hence the risks of radiation-induced circulatory disease at those earlier times are lower. A variety of biological response modifiers have been used to help reduce late reactions in many tissues. These include antioxidants, radical scavengers, inhibitors of apoptosis, anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, growth factors, and cytokines. In many cases, these give dose modification factors of 1.1-1.2, and in a few cases 1.5-2, indicating the potential for increasing threshold doses in known exposure cases. In contrast, there are agents that enhance radiation responses, notably other cytotoxic agents such as antimetabolites, alkylating agents, anti-angiogenic drugs, and antibiotics, as well as genetic and comorbidity factors. Most tissues show a sparing effect of dose fractionation, so that total doses for a given endpoint are higher if the dose is fractionated rather than when given as a single dose. However, for reactions manifesting very late after low total doses, particularly for cataracts and circulatory disease, it appears that the rate of dose delivery does not modify the low incidence. This implies that the injury in these cases and at these low dose levels is caused by single-hit irreparable-type events. For these two tissues, a threshold dose of 0.5Gy is proposed herein for practical purposes, irrespective of the rate of dose delivery, and future studies may elucidate this judgement further.

https://journals.sagepub.com/doi/pdf/10.1016/j.icrp.2012.02.001

ICRP PUBLICATION 118: ICRP Statement on Tissue Reactions and Early and Late Effects of Radiation in Normal Tissues and Organs – Threshold Doses for Tissue Reactions in a Radiation Protection Context

Lichen myxedematosus (LM) is an idiopathic cutaneous mucinosis; its classification dates back to 1953, when Montgomery and Underwood distinguished 4 types of LM: a generalized lichenoid eruption, later called scleromyxedema, a discrete papular form, a localized or generalized lichenoid plaque form, and an urticarial plaque form. In the literature, the terms LM, papular mucinosis, and scleromyxedema have been often used indiscriminately as synonyms, but most reported cases of LM or papular mucinosis without indication of the subtype appear in fact to be cases of scleromyxedema. On the basis of personal experience, the anatomoclinical manifestations of published cases of LM, papular mucinosis, and scleromyxedema are reviewed to distinguish clearly between a generalized form with systemic, even lethal, manifestations and a localized form, which does not run a disabling course. LM includes two clinicopathologic subsets: a generalized papular and sclerodermoid form (also called scleromyxedema) and a localized papular form. Diagnosis of scleromyxedema should fulfill the following criteria: (1) generalized papular and sclerodermoid eruption; (2) mucin deposition, fibroblast proliferation, and fibrosis; (3) monoclonal gammopathy; and (4) the absence of thyroid disease. The criteria for localized LM are as follows: (1) papular or nodular/plaque eruption; (2) mucin deposition with variable fibroblast proliferation; and (3) the absence of both monoclonal gammopathy and thyroid disease. The localized form is subdivided into 5 subtypes: (1) a discrete papular form involving any site; (2) acral persistent papular mucinosis involving only the extensor surface of the hands and wrists; (3) self-healing papular mucinosis, of a juvenile and an adult type; (4) papular mucinosis of infancy, a pediatric variant of the discrete form or of acral persistent papular mucinosis; and (5) nodular form. A third group of atypical or intermediate forms, not meeting the criteria for either scleromyxedema or the localized form, includes cases of (1) scleromyxedema without monoclonal gammopathy, (2) localized forms with monoclonal gammopathy and/or systemic symptoms, (3) localized forms with mixed features of the 5 subtypes, and (4) not well-specified cases. (J Am Acad Dermatol 2001;44:273-81.)

Updated classification of papular mucinosis, lichen myxedematosus, and scleromyxedema.

https://www.jidonline.org/article/S0022-202X(15)32312-5/pdf

Additional evidence that pityriasis rosea is associated with reactivation of human herpesvirus-6 and -7.

Human herpesvirus 7 in pityriasis rosea

The clinical aspects and the histologic features of cutaneous mucinoses have been reviewed and their classification updated. Cutaneous mucinoses are divided into distinctive (primary) cutaneous mucinoses in which the mucin deposit is the main histologic feature resulting in clinically distinctive lesions, and disorders associated with histologic mucin deposition as an additional finding (secondary mucinoses). The former are further divided into degenerative-inflammatory mucinoses, which may be either dermal or follicular, and into neoplastic-hamartomatous mucinoses. Histopathologic diagnosis is particularly difficult for dermal mucinoses and requires clinicopathologic correlation. Three histologic clues, namely the pattern of mucin distribution (diffuse or focal), the level of mucin deposit in the dermis and some additional findings may help diagnosis. Follicular mucinoses have the easiest pattern to recognize histologically, but the distinction between Pinkus' follicular mucinosis and follicular mucinosis with mycosis fungoides is very difficult.Lastly, neoplastic-hamartomatous cutaneous mucinoses include mucinous nevus, a benign hamartoma, and myxoma, which is a benign tumor to be differentiated from reactive cutaneous focal mucinosis.

Cutaneous mucinoses: microscopic criteria for diagnosis.

https://www.cghjournal.org/article/S1542-3565%2808%2900155-9/pdf

Alfredo Rebora

Papers

Updated classification of papular mucinosis, lichen myxedematosus, and scleromyxedema.

Additional evidence that pityriasis rosea is associated with reactivation of human herpesvirus-6 and -7.

Human herpesvirus 7 in pityriasis rosea

Cutaneous mucinoses: microscopic criteria for diagnosis.

Small intestinal bacterial overgrowth in rosacea: clinical effectiveness of its eradication