Subduction-driven recycling of continental margin lithosphere.

Whereas subduction recycling of oceanic lithosphere is one of the central themes of plate tectonics, the recycling of continental lithosphere appears to be far more complicated and less well understood. Delamination and convective downwelling are two widely recognized processes invoked to explain the removal of lithospheric mantle under or adjacent to orogenic belts. Here we relate oceanic plate subduction to removal of adjacent continental lithosphere in certain plate tectonic settings. We have developed teleseismic body wave images from dense broadband seismic experiments that show higher than expected volumes of anomalously fast mantle associated with the subducted Atlantic slab under northeastern South America and the Alboran slab beneath the Gibraltar arc region; the anomalies are under, and are aligned with, the continental margins at depths greater than 200 kilometres. Rayleigh wave analysis finds that the lithospheric mantle under the continental margins is significantly thinner than expected, and that thin lithosphere extends from the orogens adjacent to the subduction zones inland to the edges of nearby cratonic cores. Taking these data together, here we describe a process that can lead to the loss of continental lithosphere adjacent to a subduction zone. Subducting oceanic plates can viscously entrain and remove the bottom of the continental thermal boundary layer lithosphere from adjacent continental margins. This drives surface tectonics and pre-conditions the margins for further deformation by creating topography along the lithosphere-asthenosphere boundary. This can lead to development of secondary downwellings under the continental interior, probably under both South America and the Gibraltar arc, and to delamination of the entire lithospheric mantle, as around the Gibraltar arc. This process reconciles numerous, sometimes mutually exclusive, geodynamic models proposed to explain the complex oceanic-continental tectonics of these subduction zones.

Subungual squamous cell carcinoma and exostosis in third toe--case report and literature review.

BACKGROUND: Squamous cell carcinoma (SCC) in the ungual apparatus is a rare neoplasia. Although it is the most prevalent malignant tumour in this region, its diagnosis is often delayed because it is likened to benign or infectious processes. OBJECTIVES: Present a case of SCC with subungual location in a toe, and carry out a review of the literature in relation to the most important aspects of subungual SCC in toes. METHODS: We describe the case of a white woman aged 72, with SCC located in the pulp and in the distal area of the nail bed of the third toe, associated with subungual exostosis. The literature on SCC in the subungual area of toes, in all its forms under clinical or histopathological presentation, is reviewed by means of a search involving Medline, PubMed, and Google Academic, from January 1994 to December 2011. RESULTS: Only 36 cases of subungual SCC in toes were reported in the 18 years that were reviewed. The average age of cases reviewed was 58.92, and the male-to-female ratio was 2:1. The most affected toe is the hallux, in 69.4% of cases. In 50% of cases, aetiology is unknown or indeterminate; in 22.3% of cases, aetiology is metastatic; and in 19.5% of cases, it is associated with human papillomavirus (HPV). In 58.2% of cases, partial or total resection of the distal phalanx was carried out, of the entire toe, or of the osseous ray of the foot. CONCLUSIONS: Chronic tissue irritation caused by microtrauma associated with subungual exostosis is the most probable aetiology of the case presented.

Plasma corticotropin-releasing factor in depressive disorders.

BACKGROUND: The aim of this work was to investigate alterations of plasma corticotropin-releasing factor (CRF) levels in depressive states. We have also measured plasma cortisol and corticotropin (ACTH) concentrations and examined their correlation with the peripheral CRF values. METHODS: Thirty-six outpatients from the psychiatric department of a Barcelona hospital who were diagnosed as having major depressive disorder (n = 26) and dysthymic depressive disorder (n = 10) were studied. Among the major depressed patients, 10 suffered from severe depressive disorder and 16 from mild or moderate depressive disorder. The comparison group consisted of 17 healthy volunteers. Cortisol, ACTH, and CRF concentrations were determined by iodine-125 radioimmunoassay; CRF measurements were performed on C18 extracted samples. RESULTS: CRF and cortisol plasma concentrations were significantly higher in major depression and dysthymia than in the comparison group. The major depressed patients did not show significantly different CRF and cortisol levels than the dysthymic. Severe major depressive disorder exhibited significantly higher CRF plasma levels than the mild or moderate episodes. Plasma cortisol and CRF concentrations correlated significantly. CONCLUSIONS: The results obtained indicate that plasma CRF values are altered in depressive disorders and suggest that these determinations could be important for understanding the pathophysiology in affective illness.

Salivary cortisol levels and their correlation with plasma ACTH levels in depressed patients before and after the DST.

OBJECTIVE: The aim of this work was to study the clinical utility of salivary cortisol concentrations in a group of depressed patients undergoing the dexamethasone suppression test (DST) and the correlation of these concentrations with plasma ACTH levels. METHOD: Twenty outpatients from the psychiatric department of a Barcelona hospital who were diagnosed as having nonendogenous (N = 9) or endogenous (N = 11) depression according to DSM-III criteria and the Newcastle scale participated in the study. The comparison group consisted of 12 healthy volunteers. Blood and saliva samples were taken before and after administration of 1 mg of dexamethasone Salivary cortisol and plasma ACTH concentrations were determined by direct iodine-125 radioimmunoassay with commercial kit reagents. RESULTS: Predexamethasone salivary cortisol concentrations were significantly higher in the group with endogenous depression than in the comparison group. A significant correlation was obtained between plasma ACTH and predexamethasone salivary cortisol levels in the group with nonendogenous depression and in the comparison subjects. CONCLUSIONS: These preliminary findings indicate that salivary cortisol could substitute for plasma cortisol in clinical studies in which the DST and hypercortisolemia are evaluated. The lack of correlation between ACTH and cortisol levels in saliva in the group of endogenously depressed patients could indicate a disturbance in the regulation of cortisol secretion in major depression.

[Chronic inflammatory intestinal disease in Catalonia (Barcelona and Gerona)]. / Enfermedad inflamatoria crónica intestinal en Cataluña (Barcelona y Gerona).

We show the results of a retrospective study carried out during ten years (1978-1987), in Catalonia in the provinces of Barcelona and Gerona. The aim of the study was to evaluate the incidence and prevalence of inflammatory chronic bowel disease in our country, its clinical aspects, management and long term survival. An epidemiological inquiry was sent to all the hospitals and gastroenterologists of Catalonia. Nine hundred and seventy six answers were received from 20 Hospitals and four specialists. All of them were revised by the Research Committee, and 761 were validated for their inclusion in the study. The prevalence of the disease was similar both in Barcelona (19 per 100,000) and Gerona (18 per 100,000). The incidence of ulcerative colitis increased during the study, from 0.4 in 1978 to 0.8 in 1987, with a peak of maximum incidence (1.0 per 100,000) in 1985. In the same way, an increase in the incidence of Crohn's disease from 0.2 to 0.7 per 100,000, was observed. The mean incidence per year was 0.6 and 0.4 respectively, similar to the incidence observed in other Spanish regions during the same period of time. Finally we show the most important clinical and therapeutic aspects as well as the survival data.

Neuroma under the fifth metatarsal head. A retrospective study.

This retrospective study was carried out over 83 surgical cases at the distal portion of the fifth metatarsal, compromising the treatment of tailor's bunion, fifth metatarsal overload and the concomitant presence of both pathologies in some cases. Neuromas were founded under the fifth metatarsal head in 18 of the cases studied (21.7%). The results look at whether if there is an association between different fifth metatarsal pathologies and the presence of neuromas and found a significant association between the appearance of neuromas in patients with the same metatarsal overload, especially if it is accompanied by a tailor's bunion pathology.

Plasma levels of beta-endorphin, cortisol, prolactin and growth hormone in depressed patients.

Basal serum cortisol, growth hormone, prolactin and immunoreactive (IR) plasma beta-endorphin levels were measured in 31 depressed patients (14 endogenous, 17 nonendogenous) undergoing the dexamethasone suppression test. The endogenously depressed patients had significantly higher (22.55 +/- 1.34 micrograms/dl) predexamethasone cortisol levels than the nonendogenous patients (16.34 +/- 1.93 micrograms/dl). The mean serum prolactin and growth hormone values of these two groups were not significantly different, while plasma IR-beta-endorphin levels of the endogenous group (40.11 +/- 3.57 pg/ml) were significantly lower than those of the nonendogenous group (120.33 +/- 27.98 pg/ml). Neither group showed a significant correlation between plasma IR-beta-endorphin and serum cortisol values. These results indicate that measurement of predexamethasone serum cortisol values and plasma IR-beta-endorphin could be valuable laboratory tests in the diagnosis of depression.