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Medical Sciences	50%

Selected Abstracts

Clinical presentations of alopecia areata

DERMATOLOGIC THERAPY, Issue 4 2001
Maria K. Hordinsky
Alopecia areata (AA) may can occur on any hair-bearing region. Patients can develop patchy nonscarring hair loss or extensive loss of all body hair. Hair loss may fluctuate. Some patients experience recurrent hair loss followed by hair regrowth, whereas others may only develop a single patch of hair loss, never to see the disease again. Still others experience extensive loss of body hair. The heterogeneity of clinical presentations has led investigators conducting clinical therapeutic trials to typically group patients into three major groups, those with extensive scalp hair loss [alopecia totalis (AT)], extensive body hair loss [alopecia universalis (AU)], or patchy disease (AA). Treatment outcomes have been correlated with disease duration and extent. Recently, guidelines were established for selecting and assessing subjects for both clinical and laboratory studies of AA, thereby facilitating collaboration, comparison of data, and the sharing of patient-derived tissue. For reporting purposes the terms AT and AU, though still used are defined very narrowly. AT is 100% terminal scalp hair loss without any body hair loss and AU is 100% terminal scalp hair and body loss. AT/AU is the term now recommended to define the presence of AT with variable amounts of body hair loss. In this report the term AA will be used broadly to encompass the many presentations of this disease. Development of AA may occur with changes in other ectodermal-derived structures such as fingernails and toenails. Some investigators have also suggested that other ectodermal-derived appendages as sebaceous glands and sweat glands may be affected in patients experiencing AA. Whether or not function of these glands is truly impaired remains to be confirmed. Many patients who develop patchy or extensive AA complain of changes in cutaneous sensation, that is, burning, itching, tingling, with the development of their disease. Similar symptoms may occur with hair regrowth. The potential involvement of the nervous system in AA has led to morphologic investigations of the peripheral nervous system as well as analysis of circulating neuropeptide levels. In this article the clinical presentations of AA are reviewed. The guidelines for conducting treatment studies of AA are presented and observations on changes in cutaneous innervation are introduced. Throughout the text, unless otherwise noted, AA will be used in a general way to denote the spectrum of this disease. [source]

Using patch studies to link mesoscale patterns of feeding and growth in larval fish to environmental variability

FISHERIES OCEANOGRAPHY, Issue 4 2002
John F. Dower
We present results from a series of three patch studies designed to examine links between environmental variability and mesoscale patterns of feeding and growth of larval radiated shanny (Ulvaria subbifurcata). We examine the effects of variability in temperature, turbulence and prey concentration on both the mean (i.e. population level) and the variance (i.e. individual level) of larval feeding and growth rates among the three bays. Although both gut fullness and growth rates differ significantly between bays, our results show only weak environmental influences. When larvae are pooled across bays (i.e. treated as independent observations), environmental factors generally explain <4% of the variability in gut fullness. When treated as daily mean residuals, however, temperature accounts for 41% of the variability in mean gut fullness, while both temperature and prey concentration also explain significant portions of the variance in gut fullness (38 and 43%, respectively). Between-bay differences in larval growth rates are consistent with patterns of temperature variation but not with patterns of prey availability. Studies relying on tracking a single patch of larvae typically suffer from having too few observations to detect significant relationships between feeding or growth and environmental variables. By following three patches we collected a larger number of observations. However, as we encountered only a limited range of environmental conditions it remains difficult to adequately assess the role of environmental factors. In part, this problem stems from the inability of fisheries oceanographers to track the recent environmental history of individual larvae on the same fine scales currently employed to collect biological data (e.g. guts and otoliths) on individuals. [source]

The development of cutaneous lesions during follow-up of patients with primary neuritic leprosy

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 3 2005
Sujai Suneetha PhD
Background, Primary neuritic leprosy (PNL) is a rare form of leprosy where the characteristic skin lesions are absent. Investigations of apparently normal skin from the areas of sensory change have revealed microscopic evidence of nerve involvement. Clinical studies have found that a proportion of patients develop visible skin lesions during follow-up. The aim of the study was to perform a clinical and histological analysis of PNL patients who developed visible skin lesions during treatment and follow-up, to gain insight into the pathogenesis of the disease. Methods, Twenty-nine individuals in a series of 182 PNL patients developed visible skin lesions during follow-up. Analysis of the number, location, histology and time of onset of the new skin lesions in relation to the type and regularity of the treatment regimen were noted. A biopsy from the new skin lesion when available was compared with the nerve biopsy findings at the time of initial diagnosis. Results, Thirty-eight per cent of patients developed a single patch and 28% developed two patches. Over three-quarters of these were on the lower limb (47%) or the upper limb (29%). Sixty-two per cent of patients developed the lesions within 2 years of the onset of symptoms. Patients on regular treatment developed patches earlier than those on irregular treatment or no treatment. A skin biopsy from the new patch revealed borderline tuberculoid leprosy histology in 47% of the patients. Conclusions, The findings suggest that leprosy primarily affects the nerve and that a neuritic phase precedes the development of visible cutaneous lesions. [source]

The inner ear of the lungfish Protopterus

THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 3 2004
Christopher Platt
Abstract The sensory end organs of the inner ear of the lungfish, Protopterus, were examined using scanning and transmission electron microscopy. The utricle has a structure and hair cell orientation pattern that are typical for vertebrates, although the hair cells are unusually large. There are the typical three semicircular canals extending from the utricle, with the typical hair cell orientations, but the lateral canal sensory crista looks like the "hemicrista" of some amphibians and amniotes, lacking a saddle-shaped flare on one wall of the ampulla. Unlike most vertebrates that have the saccule and lagena as two separate pouches ventral to the utricle, the lungfish has a single large ventral pouch that contains a single large pasty otoconial mass. This mass covers two hair cell patches, each like a striola with prominent hair cell ciliary bundles, that are presumed to represent saccular and lagenar maculae. However, these two major sensory patches are not completely separate maculae because they lie within a less densely populated field of smaller hair cells, which forms an extrastriolar region that surrounds and fills the region between the two striolae of higher hair cell density. The more caudal lagenar striola is a vertically elongated stripe with hair cell orientation vectors facing antiparallel on either side of a midline drawn vertically along the macula, resembling the macula lagena of some bony fishes but not of tetrapods. The more rostral saccular striola is a curving band with hair cell orientation vectors facing away from its midline, but because this macula curves in three dimensions, the vectors at the rostral end of this striola are oriented mediolaterally, whereas the vectors on the caudal half of this striola are oriented dorsoventrally. The presence of a macula neglecta was confirmed near the posterior canal as a tiny single patch of a few dozen hair cells with all the cell orientations directed caudally. The ciliary bundles on the cells in the striolar-like regions of all of three otolithic organs average over 80 cilia, a number far greater than for any other fish studied to date. The features of the single sacculolagenar pouch with separate striolar-like regions, the cellular orientation in the otolith organs, and the large cells and ciliary bundles in Protopterus also were observed in specimens of the other extant lungfish genera, Lepidosiren and Neoceratodus. J. Comp. Neurol. 471:277,288, 2004. © 2004 Wiley-Liss, Inc. [source]