The release of glutamate, aspartate, GABA, and taurine from the striatum of young (3 months), mature (12 months), and old (22 months), freely moving male rats was investigated by using a microdialysis fiber inserted transversally in the striatum. In old rats basal extracellular glutamate and aspartate levels were decreased vs. young rats (-38 and -49%, respectively). GABA and taurine levels were unmodified by age. In the presence of the adenosine receptor antagonist 8-phenyltheophilline (8-pT) at the concentration of 50 microM, both K(+)-evoked releases of glutamate and aspartate were more than doubled in young, but not in mature and old rats. 8-pT at the concentration of 500 microM significantly decreased glutamate basal levels and K(+)-evoked aspartate release in old rats only. GABA and taurine releases were not affected by 8-pT at either dose. Our findings indicate a modified adenosine modulation on glutamate and aspartate release in aged rats, that could result from a change in the balance between A1 and A2a adenosine receptor density or an alteration of A1 and A2a receptor-effector coupling.

Adenosine↗

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Hyperparathyroidism and anemia in renal failure.

Patients with severe secondary hyperparathyroidism, usually associated with osteitis fibrosa on bone histology, show considerable resistance to Epoetin, partly because of replacement of the cellular components of the bone marrow by fibrous tissue. In case of unexplained resistance to Epoetin, investigation of secondary hyperparathyroidism is strongly recommended, with measurement of serum parathyroid hormone, calcium, phosphate, and alkaline phosphatase levels and, where needed, skeletal radiology and bone biopsy. Treatment of severe secondary hyperparathyroidism consists of active vitamin D metabolites or parathyroidectomy, although the marrow fibrosis, if present, may be irreversible. The finding of a progressive inability of the bone marrow to respond to Epoetin treatment with higher levels of parathyroid hormone suggests the importance to prevent metabolic bone disease and in particular secondary hyperparathyroidism. Moreover, there are several reports of a beneficial action on hemoglobin levels of an effective treatment of hyperparathyroidism. Larger, controlled studies are necessary to confirm these preliminary and exciting findings, and to elucidate the mechanisms underlying the improvement in anemia after medical or surgical treatment of hyperparathyroidism.

Anemia↗

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Changing patterns of ocular manifestations in HIV seropositive patients treated with HAART.

PURPOSE: To report the changing patterns of ocular manifestations in human immunodeficiency virus (HIV) seropositive patients treated with highly active antiretroviral therapy (HAART). METHODS: The clinical charts of HIV seropositive patients, 735 examined from 1997 to 2003 and treated with HAART for at least 2 months (Group 1), and 838 untreated examined from 1988 to 1995 (Group 2), were reviewed to assess the frequency of ocular manifestations. RESULTS: HIV-related retinal microangiopathy and opportunistic retinal infections (cytomegalovirus retinitis and toxoplasmic retinochoroiditis) were significantly higher in Group 2 than 1 (p<0.0001), while in patients treated with HAART a statistically significant increase in the frequency of chalazion (p<0.0001), diabetic and hypertensive retinopathy (p<0.0001), lipid arc of the cornea (p<0.0001), cataract and glaucoma (p<0.0001), and uveitis (p=0.026) was observed. CONCLUSIONS: HAART therapy has induced a dramatic decrease in the incidence of HIV-related microangiopathy and opportunistic retinal infection and the occurrence of new lesions related both to the metabolic alterations induced by HAART and to immune reconstitution, such as uveitis.

Adolescent↗

PubMedDate not supplied