Epigenetic Patterns Maintained in Early Caenorhabditis elegans Embryos Can Be Established by Gene Activity in the Parental Germ Cells

Epigenetic information, such as parental imprints, can be transmitted with genetic information from parent to offspring through the germ line. Recent reports show that histone modifications can be transmitted through sperm as a component of this information transfer. How the information that is transferred is established in the parent and maintained in the offspring is poorly understood. We previously described a form of imprinted X inactivation in Caenorhabditis elegans where dimethylation on histone 3 at lysine 4 (H3K4me2), a mark of active chromatin, is excluded from the paternal X chromosome (Xp) during spermatogenesis and persists through early cell divisions in the embryo. Based on the observation that the Xp (unlike the maternal X or any autosome) is largely transcriptionally inactive in the paternal germ line, we hypothesized that transcriptional activity in the parent germ line may influence epigenetic information inherited by and maintained in the embryo. We report that chromatin modifications and histone variant patterns assembled in the germ line can be retained in mature gametes. Furthermore, despite extensive chromatin remodeling events at fertilization, the modification patterns arriving with the gametes are largely retained in the early embryo. Using transgenes, we observe that expression in the parental germline correlates with differential chromatin assembly that is replicated and maintained in the early embryo. Expression in the adult germ cells also correlates with more robust expression in the somatic lineages of the offspring. These results suggest that differential expression in the parental germ lines may provide a potential mechanism for the establishment of parent-of-origin epigenomic content. This content can be maintained and may heritably affect gene expression in the offspring

Dermatopathology of Lyme borreliosis

The dermatopathology of the entire spectrum of skin lesions in Lyme borreliosis is rendered in text and, in most cases, is illustrated. Special emphasis is placed on the histopathological findings in fresh tick bites as the site of entry for borrelia organisms, and their differentiation from other insect bites. The course of the lesions in the well-established B. burgdorferi-induced dermatoses is histologically described and illustrated. In addition, conditions in which considerable evidence points to a borrelial etiology are delineated. These include morphea-like plaques, lymphocytic infiltration of the skin, panniculitides, lichen sclerosus et atrophicus, and cutaneous B-cell lymphomas. Furthermore, the recent immunological findings in these diseases are elucidated

Congenital pseudomelanoma KONGENITALES PSEUDOMELANOM

Benign congenital melanocytic nevi, removed shortly after birth, may histologically be misinterpreted as malignant melanomas. We present the criteria for the differential diagnosis. As a name for these unusual melanocytic tumors, which belong to the large group of pseudomalignancies of the skin, we suggest the term 'congenital pseudomelanoma'

FACS - Analysis of peripheral T-lymphocyte subpopulations in psoriasis FACS - ANALYSE PERIPHERER T-LYMPHOZYTENSUBPOPULATIONEN BEI PSORIASIS

By means of the fluorescence activated cell sorter (FACS), we analyzed the T-lymphocyte subpopulations in peripheral blood samples from 82 patients showing various clinical manifestations of psoriasis. With regard to both the absolute values of T-helper and T-suppressor cells and those of the T-helper/T-suppressor cell ratios, there were no quantitative differences between the patients (i.e. either the entire collective of classified according to the various forms of psoriasis) and the control group. We discuss the pathophysiological relevance of peripheral and in situ analyses of T-lymphocyte subpopulations

Dermatopathologic diagnosis of Lyme Borreliosis

The goal of this study was to determine the general light microscopic findings which lend support to the histopathologic diagnosis of the main cutaneous manifestations of Lyme Borreliosis. Their diagnostic criteria are delineated and illustrated. In culminating lesions of erythema migrans and acrodermatitis chronica atrophicans, a peculiar connective tissue reaction includes an increase in the number of fibroblasts, proliferation of collagen fibers, and interstitial mucinous edema. The cellular infiltrates are patchy perivascular in erythema migrans and either patchy and/or band-like in acrodermatitis chronica atrophicans. They consist of lymphohistiocytic cells with a variable admixture of plasma cells. The damage to elastic (and even collagen) fibers occurs in early acrodermatitis chronica atrophicans and is reflected by the phenomenon of elastophagocytosis. Reduction or lack of pilosebaceous units is a constant finding. In advanced lesions of acrodermatitis chronica atrophicans, a thinning of the dermal breadth is noticed, resulting from a decrease in collagen and elastic fibers. Fibrous nodules and morphea-like conditions are characterized by excessive formation of collagen. Borrelial lymphocytoma exhibits two different patterns of infiltration, accompanied by dermal fibrosis and increased numbers of fibroblasts. Recent tick bites show a predominantly neutrophilic infiltrate. By applying the results of this synoptic study, histopathologic diagnosis of dermatoborrelioses should be possible without the absolute necessity of clinical correlation