Effect of acute tyrosine depletion in using a branched chain amino-acid mixture on dopamine neurotransmission in the rat brain.

Central dopamine function is reduced by decreasing the availability of the catecholamine precursor, tyrosine, using a tyrosine-free amino acid mixture containing multiple large neutral as well as branched chain amino-acids, which compete with tyrosine for uptake into the brain. Current mixtures are cumbersome to make and administer, and unpalatable to patients and volunteers. Here, we investigate whether individual or limited amino-acid combinations could reduce brain tyrosine levels and hence dopamine function. Measurements of regional brain tyrosine levels, catecholamine and indoleamine synthesis (L-DOPA and 5-HTP accumulation, respectively) were used to identify an effective paradigm to test in neurochemical, behavioral and fos immunocytochemical models. Administration of leucine or isoleucine, or a mixture of leucine, isoleucine, and valine reduced tyrosine and 5-HTP, but not L-DOPA accumulation. A mixture of leucine, valine, and isoleucine supplemented with tryptophan reduced brain tyrosine and L-DOPA, but not 5-HTP. In microdialysis experiments this amino-acid mixture reduced basal and amphetamine-evoked striatal dopamine release, as well as amphetamine-induced hyperactivity. This mixture also reduced amphetamine-induced fos expression in striatal areas. In conclusion, the present study identified a small combination of amino acids that reduces brain tyrosine and dopamine function in a manner similar to mixtures of multiple amino acids. This minimal mixture may have use as a dopamine reducing paradigm in patient and volunteer studies.     

Management of the side-effects of intravenous bisphosphonates: targeting the serum parathyroid hormone elevation.

In their recent review article, Tanvetyanon and Stiff [1] pointedout that hypocalcemia is a frequent side-effect of intravenousbisphosphonates. This adverse event is usually mild and exceptionallysymptomatic, with the principle risk factors being pre-existinghypovitaminosis D, previous parathyroid surgery and intestinalresections. A direct consequence of hypocalcemia     

Nephrotic syndrome in a mother and her infant: relationship with cytomegalovirus infection

This case report describes infantile nephrotic syndrome (NS) in a baby girl with a clinically severe cytomegalovirus (CMV) infection. Culture of the baby's urine was positive for CMV and IgM anti-CMV antibodies were detected. After an unsuccessful course of corticosteroids, gancyclovir treatment was started and a remission of cutaneous, pulmonary, and renal symptoms was achieved. As the mother also developed NS at the end of pregnancy, a common etiology could be postulated, although there were no signs of recent CMV infection in the mother, only anti-CMV IgG. The relationship between CMV infection and glomerular disease is still unclear: NS may represent another manifestation of CMV disease.     

Limited role of aortic size in the genesis of acute type A aortic dissection

Objective: Increased dimension of the aortic root and proximal aorta is considered a significant risk factor for catastrophic events that involve the ascending aorta. The objective of this study was to determine the possible correlation between pre-dissection aortic diameter and the occurrence of Stanford type A aortic dissection. Methods: Samples of dissected ascending aortas were obtained from 220 patients at the time of their operation. Two groups were identified: patients with connective tissue disorders (Group 1, n = 94) and those without (Group 2, n = 126). Measurements of the true (intimal) lumen were conducted and extrapolated as reliable approximation of pre-dissection aortic diameter. The possible association of intimal diameter with anthropometric and demographic data was analyzed. Results: Median aortic diameter was, respectively, 41.8 and 41.3 mm for patients with and without connective tissue disorders (41.4 mm for the entire cohort). Data analysis indicated that 57% of patients had aortic diameter above 40 mm, while patients with frank aneurysm accounted only for 10%; this proportion was higher in Group 1 compared to Group 2 (17.2% vs 4.7%). Poor or no correlation was demonstrated between aortic size and any of the anthropometric or demographic variables essayed. Significant subgroup differences were found among patients with a history of cigarette smoking, hypertension, diabetes, chronic renal insufficiency, and bicuspid aortic valve. Conclusion: Although aortic diameter remains a strong indication for preventive surgery in patients with inherited connective tissue disorders, acute aortic dissection occurs rarely in the setting of true ascending aortic aneurysms, and despite normal or near-normal aortic size in more than one-third of subjects. Dissection superimposing on small aortic diameters can be regarded as an expression of substantial functional tissue susceptibility to aortic catastrophic events.     

Pediatric lupus versus adult lupus role of the laboratory

Systemic lupus erythematosus (SLE) is the archetypical immunologic disease. Approximately 20% of patients present in the first two decades of life. This article highlights some of the differences between pediatric and adult onset lupus.Children are defined as different from adults on the basis of age. Lupus presents with different gender ratios based on hormonal or pubertal status with more significant skewing toward female patients in the childbearing years. Female patients in the childbearing years appear to have a higher relative risk for mortality. Despite this, children have greater disease severity at onset based on the number of patients who present with significant organ inflammation, the amount of corticosteroids required and the abnormalities in lupus serologies including autoantibodies and low complements. Children present frequently with congenital and acquired complement defects. Children have an increased risk of infections that can be confused with lupus. They have a higher risk of serious pneumococcal infection and may have less protection from vaccinations received at the time of disease onset.The clinical immunology laboratory is critical in the diagnosis and treatment of pediatric SLE. The rapid analysis and transfer of laboratory results can be life saving for the child with suspected new onset lupus. The laboratory is also helpful in determining disease activity through analysis of immunologic trends over time in pediatric lupus patients. This is especially important in the noncompliant adolescent patient who has a correlation between disease activity and lupus serologic tests. Finally, the clinical immunology laboratory is an important tool for better understanding of the immunologic phenomena associated with lupus and of disease pathophysiology.     

Primary lymphoma of the temporal bone.

Involvement of the temporal bone by lymphoreticular neoplasm is rare; all reported cases have been of secondary involvement. This article presents what we believe to be the first two reported cases of primary temporal bone lymphoma. The patients, an elderly man and a boy, both presented with infection of the ear, hearing loss, and facial nerve paresis. In both cases, facial paresis resolved after appropriate chemotherapeutic treatment. Patient presentation and clinical course are discussed in light of published work on temporal bone malignancy. Further investigation, including computed tomography and biopsy, should be considered for patients who present with an apparent middle ear infection unresponsive to medical therapy. The development of facial paralysis in such a patient warrants heightened suspicion of malignancy.