Calcinosis pseudotumoral en esclerodermia / Pseudotumoral calcinosis in systemic sclerosis

La calcinosis es una manifestación frecuente en la esclerodermia sistémica. Sin embargo, la calcinosis pseudotumoral es de presentación excepcional. Las radiografías o tomografía axial computada son de utilidad para el diagnóstico y el seguimiento. Aunque no existe un tratamiento estandarizado efectivo, la remoción quirúrgica de las lesiones sintomáticas y algunos fármacos son útiles en algunos enfermos. Se presenta el caso de una paciente de 23 años con esclerodermia sistémica variedad limitada que desarrolló múltiples lesiones pseudotumorales.

Soft tissue calcinosis is a common cutaneous manifestation in systemic sclerosis. However, pseudotumoral calcinosis is rare. Radiographs or computed tomography are useful tools to diagnose and assess this condition. Although no treatment was uniformly effective, surgical excision of symptomatic lesions and medical treatment provided benefit for some patients. We report here a case of a 23 year old woman, suffering from limited cutaneous systemic sclerosis, who developed many pseudo tumoural calcinosis lesions.

Occurrence of B chromosomes in lizards: a review.

Although B chromosomes have been reported in many species of plants and animals, few studies have revealed the presence of these extra chromosomes in lizards. B chromosomes of lizards show different morphologies and sizes, from microchromosomes to macrochromosomes, or elements of intermediate size between smaller and larger A chromosomes, and number variability at intra- and inter-individual levels. In most cases, they are late-replicating and show either heterochromatic or no distinctive patterns after C-banding. The great majority of the publications about supernumerary chromosomes in this group have been based on conventional staining analyses, and there is no study designed to address questions related to their composition and structure or origin and evolution.

Chromosomal studies on sphaerodactyl lizards of genera Gonatodes and Coleodactylus (Squamata, Gekkonidae) using differential staining and fragile sites analyses.

The karyotypes of three species of sphaerodactyl gekkonid lizards are described after conventional and differential staining. Karyotypes of Gonatodeshumeralis and G. hasemani are formed by a gradual series of 32 acrocentric chromosomes, similar to those already published for other species of the genus. G. humeralis shows multiple Ag-NORs with intra-individual variability, and positive C-bands located at centromeric and telomeric regions of several chromosome pairs. Coleodactylus amazonicus, the first non-Gonatodes sphaerodactyl studied so far karyologically, exhibits 36 acrocentric/subtelocentric chromosomes and a single pair of Ag- NORs. Fragile sites were detected on two medium-sized chromosome pairs in the karyotype of G. humeralis, most of them obtained in BrdU-treated culture preparations. These sites may represent a putative fission/fusion spot involved in the differentiation of G. humeralis-like 2n = 32 and C. amazonicus-like 2n = 36 karyotypes. Our results, especially on the location of Ag-NORs and the description of fragile sites, are relevant in improving our knowledge about the events of chromosome evolution in this extremely variable and poorly known group of lizards.

A search for a mesencephalic periaqueductal gray-cochlear nucleus connection.

Horseradish peroxidase placed into the ventral mesencephalic periaqueductal gray (PAG) and in the lateral superior olivary complex region demonstrated indirect paths towards the cochlear nucleus (CN). Because no direct connections could be observed, a pathway throughout the auditory efferent system was proposed. The results suggest three possibilities: 1) The PAG is connected to the lateral superior peri-olivary complex synapsing with known efferent fibers that reach the CN; 2) Neurons located at the dorsal PAG were demonstrated to be connected to the inferior colliculus (IC). The possibility of synapses with known neurons that run from IC to the CN is postulated; 3) Neurons in the trapezoid body, which are partially associated with a system that communicates with the CN, are also connected to and from the PAG. The present results anatomically support an extracellular study (1) describing PAG actions on CN units.

A search for a mesencephalic periaqueductal gray-cochlear nucleus connection.

Horseradish peroxidase placed into the ventral mesencephalic periaqueductal gray (PAG) and in the lateral superior olivary complex region demonstrated indirect paths towards the cochlear nucleus (CN). Because no direct connections could be observed, a pathway throughout the auditory efferent system was proposed. The results suggest three possibilities: 1) The PAG is connected to the lateral superior peri-olivary complex synapsing with known efferent fibers that reach the CN; 2) Neurons located at the dorsal PAG were demonstrated to be connected to the inferior colliculus (IC). The possibility of synapses with known neurons that run from IC to the CN is postulated; 3) Neurons in the trapezoid body, which are partially associated with a system that communicates with the CN, are also connected to and from the PAG. The present results anatomically support an extracellular study (1) describing PAG actions on CN units.

A search for a mesencephalic periaqueductal gray-cochlear nucleus connection.

Horseradish peroxidase placed into the ventral mesencephalic periaqueductal gray (PAG) and in the lateral superior olivary complex region demonstrated indirect paths towards the cochlear nucleus (CN). Because no direct connections could be observed, a pathway throughout the auditory efferent system was proposed. The results suggest three possibilities: 1) The PAG is connected to the lateral superior peri-olivary complex synapsing with known efferent fibers that reach the CN; 2) Neurons located at the dorsal PAG were demonstrated to be connected to the inferior colliculus (IC). The possibility of synapses with known neurons that run from IC to the CN is postulated; 3) Neurons in the trapezoid body, which are partially associated with a system that communicates with the CN, are also connected to and from the PAG. The present results anatomically support an extracellular study (1) describing PAG actions on CN units.

Some aspects of the structural organization of the spinal cord of Gymnotus carapo (Teleostei, Gymnotiformes). I. The electromotor neurons.

The spinal electromotor neurons (EMNs) of Gymnotus carapo from a distinct column dorsal to the central canal. When massively retrograde-labeled with horseradish peroxidase, these neurons show a well-developed dendritic arborization. Dendrites run along the longitudinal axis of the cord and also project toward the dorsal gray and dorsolateral funiculi. Input to the EMNs is mediated by scarce synaptic contacts which show the fine structural characteristics of the so-called "morphologically mixed" junctions. Serial section reconstructions of the junctional areas revealed the occurrence of "gap junctions," dense membranes facing cumuli of microvesicles, and relatively large zones of undifferentiated membranes. Comparative electrophysiological and morphological data suggest that EMN activity may be mediated by electrical transmission. Since neither dendro-dendritic nor dendro-somatic junctions have been observed, other circuitry alternatives are proposed to account for the expected synchronized firing of the EMNs.