Human phagocytic cell responses to Scedosporium apiospermum (Pseudallescheria boydii): variable susceptibility to oxidative injury

Scedosporium apiospermum (Pseudallescheria boydii) is an emerging opportunistic filamentous fungus that causes serious infections in both immunocompetent and immunocompromised patients. To gain insight into the immunopathogenesis of infections due to S. apiospermum, the antifungal activities of human polymorphonuclear leukocytes (PMNs), mononuclear leukocytes (MNCs), and monocyte-derived macrophages (MDMs) against two clinical isolates of S. apiospermum were evaluated. Isolate SA54A was amphotericin B resistant and was the cause of a fatal disseminated infection. Isolate SA1216 (cultured from a successfully treated localized subcutaneous infection) was susceptible to amphotericin B. MDMs exhibited similar phagocytic activities against conidia of both isolates. However, PMNs and MNCs responded differently to the hyphae of these two isolates. Serum opsonization of hyphae resulted in a higher level of superoxide anion (O(2)(-)) release by PMNs in response to SA54A (amphotericin B resistant) than that seen in response to SA1216 (amphotericin B susceptible; P < 0.001). Despite this increased O(2)(-) production, PMNs and MNCs induced less hyphal damage to SA54A than to SA1216 (P < 0.001). To investigate the potential mechanisms responsible for these differences, hyphal damage was evaluated in the presence of antifungal oxidative metabolites as well as in the presence of a series of inhibitors and scavengers of antifungal PMN function. Mannose, catalase, superoxide dismutase, dimethyl sulfoxide, and heparin had no effect on PMN-induced hyphal damage to either of the two isolates. However, azide, which inhibits PMN myeloperoxidase activity, significantly reduced hyphal damage to SA1216 (P < 0.01) but not to SA54A. Hyphae of SA1216 were slightly more susceptible to oxidative pathway products, particularly HOCl, than those of SA54A. Thus, S. apiospermum is susceptible to antifungal phagocytic function to various degrees. The selective inhibitory pattern of azide with respect to hyphal damage and the parallel susceptibility to HOCl suggests an important difference in susceptibilities to myeloperoxidase products that may be related to the various levels of pathogenicity and amphotericin B resistance of S. apiospermum.     

Mice lacking the norepinephrine transporter are supersensitive to psychostimulants

The action of norepinephrine (NE) is terminated, in part, by its uptake into presynaptic noradrenergic neurons by the plasma-membrane NE transporter (NET), which is a target for antidepressants and psychostimulants. Disruption of the NET gene in mice prolonged the clearance of NE and elevated extracellular levels of this catecholamine. In a classical test for antidepressant drugs, the NET-deficient (NET-/-) animals behaved like antidepressant-treated wild-type mice. Mutants were hyper-responsive to locomotor stimulation by cocaine or amphetamine. These responses were accompanied by dopamine D2/D3 receptor supersensitivity. Thus altering NET expression significantly modulates midbrain dopaminergic function, an effect that may be an important component of the actions of antidepressants and psychostimulants.     

“They Assume That You’re Not Having Sex”: A Qualitative Exploration of How Paediatric Healthcare Providers Can Have Positive Sexuality-Related Conversations with Youth with Disabilities

Sexuality and Disability - Every individual should have equal access to sexuality-related information and services. Regrettably, societal stigma revolves around the sexuality of youth with...     

Effects of local fatigue of the lower limbs on postural control and postural stability in standing posture

Postural stability and postural control were studied before and after a fatigue protocol of soleus muscles. Postural stability was assessed by the centre of gravity motion, which was computed from the motion of the centre of pressure, evaluating the postural control. Ten healthy male subjects were asked to stand as still as possible with eyes open before and after the fatigue protocol, performed in a sitting position. Fatigue was assumed on the basis of a shortening of the exertion time of the soleus muscles at 60% of their maximal voluntary contraction. Results of the whole group showed that fatigue modified postural control but did not change postural stability. The same results were observed only for some subjects. However, these results indicate an increase of the neuromuscular activity in high frequencies.     

Pilot study of an HLA-A2 peptide vaccine using flt3 ligand as a systemic vaccine adjuvant

A pilot vaccine study was conducted to test the safety and immunological efficacy of four monthly immunizations of an MHC class I peptide vaccine, the E75 HLA-A2 epitope from HER-2/neu, using flt3 ligand as a systemic vaccine adjuvant. Twenty HLA-A2-expressing subjects with advanced stage prostate cancer were randomly assigned to one of four immunization or treatment schedules: (a) Flt3 ligand (20 g/kg per day) administered subcutaneously daily for 14 days on a 28-day cycle, monthly for four months; (b) flt3 ligand course as above with the E75 peptide vaccine administered on day 7 of each flt3 ligand cycle; (c) flt3 ligand course as above with the E75 peptide vaccine administered on day 14 of each flt3 ligand cycle; or (d) E75 peptide admixed with granulocyte–macrophage colony-stimulating factor and administered intradermally once every 28 days, as has previously been reported. The primary endpoints of the study were the determination of safety and immunological efficacy in generating E75-specific T cells as determined by peptide-specific interferon-gamma ELIspot. Adverse events included one grade 3 skin reaction and the development of grade 2 autoimmune hypothyroidism in two subjects with preexisting subclinical autoimmune hypothyroidism. Dendritic cells were markedly increased in the peripheral blood of subjects receiving flt3 ligand with each repetitive cycle, but augmentation of antigen-presenting cells within the dermis was not observed. Apart from a single subject, no significant peptide-specific T-cell responses were detected by ELIspot, whereas delayed-type hypersensitivity responses were detectable in control subjects and in subjects receiving peptide vaccine early in the course of flt3 ligand administration. The absence of robust peripheral immune responses in the current study may be attributable to the small numbers of subjects or differences in the subject population. In addition, the inability of flt3 ligand to augment the number of peripheral skin antigen-presenting cells may have contributed to the absence of robust peptide-specific immunity detectable in the peripheral blood of immunized subjects treated with flt3 ligand.     

Fgd1, the Cdc42 guanine nucleotide exchange factor responsible for faciogenital dysplasia, is localized to the subcortical actin cytoskeleton and Golgi membrane

FGD1, the gene responsible for the inherited disease faciogenital dysplasia, encodes a guanine nucleotide exchange factor (GEF) that specifically activates the p21 GTPase Cdc42. In order, FGD1 is composed of a proline-rich N-terminal region, adjacent GEF and pleckstrin homology (PH) domains, a FYVE-finger domain and a second C-terminal PH domain (PH2), structural motifs involved in signaling and subcellular localization. Fgd1, the mouse FGD1 ortholog, is expressed in regions of active bone formation within osteoblasts and in the osteoblast-like cell line MC3T3-E1, a finding consistent with its role in skeletal formation. Here, we use subcellular fractionation studies to show that endogenous Fgd1 protein is localized in the cytosolic and Golgi and plasma membrane fractions of mouse calvarial cells. Immunocytochemical studies performed with osteoblast-like MC3T3-E1 cells and other mammalian cell lines confirm the localization of Fgd1 and show that the proline-rich N-terminal region is necessary and sufficient for Fgd1 subcellular localization to the plasma membrane and Golgi complex. In contrast, the FYVE-finger and PH2 domains do not appear to direct the localization of Fgd1 or the activation of Cdc42. In addition, microinjection studies indicate that the N-terminal Fgd1 domain inhibits filopodia formation, suggesting that this region down-regulates GEF function. These results characterize the function of the Fgd1 domains for both protein localization and Cdc42 activation and indicate that the Fgd1 Cdc42GEF protein is involved in the regulation of Cdc42 activity at the subcortical actin cytoskeleton and Golgi complex.     

Usefulness of basement membrane markers in tumoural pathology

The distribution of basement membrane (BM) markers, type IV collagen, laminin (LM), heparan sulphate proteoglycan (HSP) and fibronectin (FN) has been studied by indirect immunofluorescence using specific antibodies, in tumoural pathology. The disrupted pattern of BM by these markers in severe dysplastic lesions of the breasts, the bronchi and uterine cervix provides evidence for malignancy. In invasive carcinomas, there is generally a loss of these BM components, with FN persisting in the stroma. The loss of these markers in BM is concomitant and superimposable in double staining studies. In embryonic tumours, the presence of BM markers is related to a mesenchymal differentiation of malignant cells with pericellular FN and/or maturation towards organoid structures with BM. In sarcomas, there is a loss of the pericellular BM staining around most transformed muscular and Schwann cells and adipocytes. The persistence of this labelling in some well-differentiated areas can help to diagnose the nature of the sarcoma. The persistence of intercellular filaments of FN corresponds to the mesenchymal and/or sarcomatous nature of undifferentiated anaplastic proliferations.     

Extreme temperament and diagnosis. A study in a psychiatric sample of consecutive children

We report on an epidemiological-clinical study of the New York (NY) Longitudinal Study temperament model in a consecutive sample of children (N = 814) referred to a child psychiatric center. Temperament comparisons in this clinical population were made by using temperament normative values obtained in previous random samples of the general population in the greater Quebec City (Canada) area. Different clinical diagnostic groups (externalized disorders, developmental delays, and mixed disorders) were derived from a review of the entire hospital charts in which the interrater reliability was tested and performed "blind" to temperament scores. The diagnostic groups were confirmed through discriminant function analyses. The results (1) replicated, in this child psychiatric population, two factors of temperament similar to those previously found in random samples of our general population; (2) showed, in the psychiatric population of children, an overproportion of difficult temperaments on both factors; (3) confirmed conversely that a large proportion of children referred for a disorder did not present with an extreme temperament, and, therefore, an extreme temperament and a clinical disorder were not equivalent; and (4) suggested a specificity in the relationship between particular temperament factors and the type of clinical problem. Temperament factor 1 (withdrawal from new stimuli, low adaptability, high intensity, and negative mood) was found to be more associated with externalized disorders (opposition, conduct, or attention-deficit disorders), whereas temperament factor 2 (low persistence, high sensory threshold, and high mobility) was found to be more associated with specific developmental delays. The findings provided leads for future clinical research on temperament, family functioning, and child psychiatric diagnoses.