Search results for "nail"
showing 10 items of 216 documents
Merkel cells in ontogenesis of human nails
1993
Digital skin of human fetuses is known to contain a particularly high concentration of Merkel cells. Using antibodies against the simple epithelial cytokeratins (CK) 18 and 20, which are sensitive and specific Merkel cell markers, we studied immunohistochemically the main adnexal structure of digital skin, the nail anlage, in human fetuses (9-22 weeks of gestation) for the presence of Merkel cells. As early as week 9 some clustered Merkel cells were detected in the early matrix primordium. In specimens of week 12-15, abundant Merkel cells were found in the nail anlagen, particularly in the epithelium of the proximal nail-fold and the dorsal and ventral side of the apex region. In contrast, …
Idiopathic Acquired Leukonychia in a 34-Year-Old Patient
2009
We present a rare case of a 34-year-old patient with persistent, progressive, acquired leukonychia totalis and partialis. Idiopathic acquired leukonychia is a rare chromatic disorder of the nail not associated with other abnormalities and discernible etiology. Our case report did not link the inheritance of leukonychia with diverse clinical syndromes. To our knowledge, only five cases of idiopathic, acquired, true total leukonychia were found in literature. This case was the sixth patient with asymptomatic idiopathic, white fingernails, and toenails without a hereditary cause.
Metabolism of phenol in the terrestrial snail Cepaea nemoralis L
1992
1. The metabolism of phenol in the terrestrial snail Cepaea nemoralis was studied after injection into the haemocoel of the dorsolateral foot region. 2. Excreted metabolites, and metabolites extracted from the body, were analysed by h.p.l.c. In addition to phenyl beta-D-glucoside, arbutine (quinol beta-D-glucoside), a new conjugate of phenol, was detected.
Land Snails as a Diet Diversification Proxy during the Early Upper Palaeolithic in Europe
2014
Despite the ubiquity of terrestrial gastropods in the Late Pleistocene and Holocene archaeological record, it is still unknown when and how this type of invertebrate resource was incorporated into human diets. In this paper, we report the oldest evidence of land snail exploitation as a food resource in Europe dated to 31.3-26.9 ka yr cal BP from the recently discovered site of Cova de la Barriada (eastern Iberian Peninsula). Mono-specific accumulations of large Iberus alonensis land snails (Ferussac 1821) were found in three different archaeological levels in association with combustion structures, along with lithic and faunal assemblages. Using a new analytical protocol based on taphonomic…
GENETIC VARIABILITY AND DRIFT LOAD IN POPULATIONS OF AN AQUATIC SNAIL
2004
Population genetic theory predicts that in small populations, random genetic drift will fix and accumulate slightly deleterious mutations, resulting in reduced reproductive output. This genetic load due to random drift (i.e., drift load) can increase the extinction risk of small populations. We studied the relationship between genetic variability (indicator of past population size) and reproductive output in eight isolated, natural populations of the hermaphroditic snail Lymnaea stagnalis. In a common laboratory environment, snails from populations with the lowest genetic variability mature slower and have lower fecundity than snails from genetically more variable populations. This result s…
Weyers acrodental dysostosis in a family.
1984
A four generation family with postaxial polydactyly of hands and feet and dental anomalies is reported. Lower and upper incisors were abnormal in shape and number. Additional findings were prominent ear anthelices, hypoplastic and dysplastic nails and mild shortness of stature. Inheritance was dominant with variable expression. It is proposed that the family presents the syndrome of acrofacial dysostosis described by Weyers in 1952. To differentiate it from other acrofacial dysostoses, we suggest naming the condition acrodental dysostosis.
The snail lemma for internal groupoids
2019
Abstract We establish a generalized form both of the Gabriel-Zisman exact sequence associated with a pointed functor between pointed groupoids, and of the Brown exact sequence associated with a fibration of pointed groupoids. Our generalization consists in replacing pointed groupoids with groupoids internal to a pointed regular category with reflexive coequalizers.
Bipullbacks of fractions and the snail lemma
2017
Abstract We establish conditions giving the existence of bipullbacks in bicategories of fractions. We apply our results to construct a π 0 - π 1 exact sequence associated with a fractor between groupoids internal to a pointed exact category.
An evaluation of a model ecosystem with DDT
1980
The reproducibility, variability, and reliability of a simple aquatic-terrtestrial model ecosystem experiment was tested with p,p'-DDT. The variation among the model replicates as well as within the units was studied by using hierarchal analysis of variance. the complete budget of the chemical was calculated and a theoretical transport model was constructed. The degradation and accumulation of DDT was followed by gas chromatographic residue analysis, which showed good reproducibility of the experimental design. The degradation of DDT in the model was similar to that found in the field, but the determination of concentration factors was questionable. The material balance tables revealed that…
A global network for the control of snail-borne disease using satellite surveillance and geographic information systems
2001
Abstract At a team residency sponsored by the Rockefeller Foundation in Bellagio, Italy, 10-14 April 2000 an organizational plan was conceived to create a global network of collaborating health workers and earth scientists dedicated to the development of computer-based models that can be used for improved control programs for schistosomiasis and other snail-borne diseases of medical and veterinary importance. The models will be assembled using GIS methods, global climate model data, sensor data from earth observing satellites, disease prevalence data, the distribution and abundance of snail hosts, and digital maps of key environmental factors that affect development and propagation of snail…