Hypocarnitinemia in lysinuric protein intolerance

Carnitine deficiency in lysinuric protein intolerance (LPI) has been reported only in a single case. We describe hypocarnitinemia in a 11 year-old male patient with LPI and relate its development to intake, biosynthesis, and uptake of carnitine.     

Alterations of thrombogenesis,endothelial damage and oxidative stress with reperfusion during femoral artery bypass surgery for peripheral vascular disease

Peripheral vascular disease (PVD) is a significant cause of cardiovascular morbidity. We hypothesised that there would be significant alterations of thrombogenesis, platelet activation and endothelial damage, which could be associated with abnormal oxidative stress during femoral artery bypass surgery for PVD, where the femoral artery is cross-clamped (causing acute ischaemia) and reperfused (following revascularisation). To test this hypothesis, we measured sequential changes in von Willebrand factor (vWF, and index of endothelial damage/dysfunction), tissue factor (TF, an index of thrombogenesis) and soluble P-selectin (sP-sel, an index of platelet activation) as well as lipid hydroperoxides (LPO, an index of oxidative stress) in 28 consecutive patients undergoing elective peripheral artery bypass surgery. Mean baseline vWF and sP-sel levels in PVD patients (before clamping) were significantly higher compared with age- and sex-matched controls (unpaired t test, both p < 0.05), but there were no significant differences in TF and LPO levels. There was a correlation between TF and vWF (Spearman's, r = 0.374, p = 0.05), as well as between sP-sel and vWF at the start of surgery (r = 0.467, p = 0.012). The patients undergoing peripheral artery bypass surgery had a mean femoral artery clamp time of 28 min (standard deviation 14 min; range 11-65 min). There were no significant overall changes in sP-sel, vWF, TF and LPO with femoral artery cross-clamping and reperfusion (repeated measures ANOVA, p = NS). In conclusion, we found that during ischaemia-reperfusion during peripheral arterial bypass surgery, thrombogenesis (as measured by plasma TF) and oxidative damage (as measured by LPO) within the affected leg does not increase in the immediate perioperative period. Further studies are required to assess the mechanism(s) of ischaemia-reperfusion injury in PVD, and the contributory role(s) of the endothelium and platelets.     

Structural mechanisms of costimulation

Recent studies have highlighted the structural requirements for T cell costimulation and have revealed unusual modes of dimerization for the cytolytic T lymphocyte-associated antigen 4 (CTLA-4) costimulatory receptor and its B7 ligands. These distinctive quaternary structures potentially endow both receptor and ligand with bivalent binding properties, which suggests a number of mechanistic features relevant to signaling. These include the potential to form a highly ordered, alternating network of CTLA-4 and B7 homodimers that may represent the organization of these molecules and their associated signaling partners within the immunological synapse. Primary sequence and structural considerations suggest that some aspects of the organizational and mechanistic features associated with the CTLA-4-B7 complexes may extend to other members of the costimulatory receptor-ligand family. An examination of the signaling mechanisms within the costimulatory receptor-ligand family provides an excellent framework to consider the general principles that are relevant to cell surface receptor-mediated signaling events.     

Cognitive development in school-age children with vertically transmitted HIV infection

We examined a broad range of neuropsychological functioning in school-age children with vertically transmitted HIV infection and a control group made up of siblings of children with HIV infection. Fourteen children with HIV (2 asymptomatic, 8 mildly symptomatic, and 4 with AIDS) and 11 control children were administered a battery of neuropsychological tests assessing intelligence, receptive language, expressive language, visual and verbal memory, visual-motor speed and coordination, visual-motor and visual-spatial processing, fine motor skill, and academic achievement. Results revealed that school-age children with vertically transmitted HIV infection show many areas of cognitive function within the normal range. Despite normal cognitive development, subtle motor impairments were documented in children with vertically transmitted HIV infection. Our results are the first report of fine motor and motor strength deficits in school-age children with vertically transmitted HIV. Lastly, computed tomography (CT) results suggest that children with HIV who have documented structural anomalies in the brain may be at risk for deficits in visual-motor and visual-spatial processing. This finding should be explored with larger samples and other measures to determine its generalizability.     

Blastomycosis

Blastomycosis is an endemic mycoses in the central United States caused by a dimorphic fungus, Blastomyces dermatitidis, that exists in nature in mycelial phase and converts to yeast phase at body temperature. The organism may produce epidemics of infection following a point source of infection or sporadic endemic infection. Blastomycosis can be a subclinical illness with subsequent protection against progressive infection afforded by cellular immune mechanisms, but it may present with progressive disease with either pulmonary or extrapulmonary disease or both. Itraconazole has been shown to be the drug of choice for both infections, except in cases of life-threatening infection when amphotericin B should be used.     

Educational attainment, positive psychological mediators, and resources for health and vitality in older adults

Objectives: To further explain the relationship of education to health by a prospective examination of positive psychological states as mediators. Furthermore, to examine the resources of desirable events, self-esteem, and social support as possible mediators between positive psychological states and subsequent health and vitality. Methods: Four in-home interviews were conducted at 6-month intervals with a probability sample of 1,277 older adults (aged 55 and older); multiple regression was used to estimate mediating effects. Results: Positive states mediated the education relationship to both symptoms and vitality, independent of negative states; the resource measures did not mediate the positive state-health relationship. Discussion: Higher education level appears to increase the likelihood of being serene and happy, and healthy and vital, in later years; positive psychological states appeared to have both a promotion function (for vitality) and protective function (against health symptoms); self-esteem showed promise as a possible mediator of the effects of psychological states on health.