Influence of calcium depletion on medullary bone of laying hens

Medullary bone of birds maintained on a low-calcium diet represents a good model to study modifications of matrix composition in calcified tissue undergoing intense formation and resorption. The composition of the bone matrix during the low-calcium diet has been analyzed by both chemical and histological techniques. Sixty White Leghorn pullets 1 year old were used for the experiment. Fifteen birds served as controls and were killed on day zero; the remaining birds were placed on a calcium-deficient diet (0.13% calcium) and sacrificed after 4, 7, and 12 days of treatment in groups of 15. Serum levels of calcium, PTH, and estrogens were also measured. Chemical analysis of the samples were made for total nitrogen, hydroxyproline, hexosamine, hexoses, calcium, and phosphorus. Collagen and proteoglycans of the matrix of medullary bone of the egg-laying hens were found to be affected by the low-calcium diet. They either increased or decreased during the experiment but never in parallel. The increment of serum PTH is considered responsible for the variations in the amount of collagen. The effects of this hormone are magnified by the fall of serum estrogens as shown also by variations in the amounts of noncollagenous protein. In the late phase of the diet the matrix is represented by poorly calcified osteoid tissue rich in noncollagenous protein, i.e., proteoglycans and glycoproteins.     

Drainage of retro-parapharyngeal abscess: an additional indication for endoscopic sinus surgery

Deep neck abscesses are life-threatening conditions, in early stages preferably treated by intravenous antibiotic therapy; in advanced stages, surgical drainage is mandatory. We report two cases of retro-parapharyngeal abscess with prevalent retronasopharyngeal extension in two men aged 60 and 82, both of whom underwent transnasal endoscopic drainage. The main surgical steps were incision of the posterior pharyngeal mucosal wall, widening of the incision, drainage of purulent collection and careful dissection and removal of the necrotic tissue. The first patient, with an abscess associated with chronic otitis media and presenting hypoglossal nerve palsy, quickly recovered from pharyngodinia, otalgia and trismus. Twenty-six months after surgery, he is symptom-free, with hemitongue atrophy due to denervation as the only residual sign. The second patient, affected by skull base osteomyelitis secondary to malignant external otitis, after a first successful drainage, underwent a second endoscopic procedure for the reoccurrence of an abscess in the contralateral retroparapharyngeal space. Twelve months after the first surgery, the patient reported an improvement of symptoms, except for persistent dysphonia related to vagal nerve palsy. At follow-up MR, another abscess was detected in the left retro-parapharyngeal space. In selected cases of abscess, transnasal endoscopic drainage may be an effective alternative to external approaches. Minimal morbidity, the absence of cervical or palatal scars and a short hospitalization time can be considered as important advantages in comparison to external approaches. Patients with abscess secondary to skull base osteomyelitis require close imaging surveillance because of the difficulty of definitive control of the disease.     

Current perspective. Diabetic vascular disease: from endothelial dysfunction to atherosclerosis.

Cardiovascular complications are the leading cause of death in diabetes. Over the past decade a number of studies have addressed the underlying mechanisms. Derangements of endothelial function, also referred to as endothelial dysfunction, have emerged to be the crucial early step in the development of atherosclerosis and are also involved in plaque progression and clinical emergence. Endothelial dysfunction is a condition of impaired endothelium-dependent vasodilation and most important of "endothelial activation", characterized by a proinflammatory, proliferative, and procoagulatory milieu that promotes initiation and complications of atherogenesis. A synergistic cross-talk among the conventional cardiovascular risk factors associated with diabetes contributes to disruption of endothelial integrity and accelerated atherosclerosis. This review will focus on the multifactorial nature of endothelial dysfunction in diabetes, the relationship between endothelial dysfunction, conventional cardiovascular risk factors and atherosclerosis, and the therapeutic options to improve endothelial function.     

Chronic systemic inflammation in uremia: potential therapeutic approaches

Systemic inflammation characterizes several chronic diseases including uremia. Inflammation may contribute to morbidity and mortality by enhancing protein-calorie malnutrition, infectious complications, and atherosclerosis and cardiovascular disease. Although inflammation in renal disease can be caused, at least in part, by reduced renal clearance of proinflammatory mediators (tumor necrosis factor [TNF]-alpha, interleukin [IL]-6), several pathogenetic mechanisms are likely to contribute to direct activation of the inflammatory process under these conditions. These mechanisms include accumulation of advance glycoxidation end products, production of reactive oxygen species and oxidative damage, and chronic infection. Support for direct activation of systemic inflammation provides a strong rationale for use of anti-inflammatory treatments in uremia. The current article describes the association between uremia and inflammation, provides evidence for activation of inflammatory process, and provides potential therapeutic approaches.