Genomic structure and evolution of the ancestral chromosome fusion site in 2q13-2q14.1 and paralogous regions on other human chromosomes

Human chromosome 2 was formed by the head-to-head fusion of two ancestral chromosomes that remained separate in other primates. Sequences that once resided near the ends of the ancestral chromosomes are now interstitially located in 2q13-2q14.1. Portions of these sequences had duplicated to other locations prior to the fusion. Here we present analyses of the genomic structure and evolutionary history of >600 kb surrounding the fusion site and closely related sequences on other human chromosomes. Sequence blocks that closely flank the inverted arrays of degenerate telomere repeats marking the fusion site are duplicated at many, primarily subtelomeric, locations. In addition, large portions of a 168-kb centromere-proximal block are duplicated at 9pter, 9p11.2, and 9q13, with 98%-99% average sequence identity. A 67-kb block on the distal side of the fusion site is highly homologous to sequences at 22qter. A third ~100-kb segment is 96% identical to a region in 2q11.2. By integrating data on the extent and similarity of these paralogous blocks, including the presence of phylogenetically informative repetitive elements, with observations of their chromosomal distribution in nonhuman primates, we infer the order of the duplications that led to their current arrangement. Several of these duplicated blocks may be associated with breakpoints of inversions that occurred during primate evolution and of recurrent chromosome rearrangements in humans.     

The AMY Antigen Co-Occurs with Aβ and Follows Its Deposition in the Amyloid Plaques of Alzheimer’s Disease and Down Syndrome

Novel plaque-like "AMY" lesions were recently described in the brains of patients with Alzheimer's disease (AD). Using three Abeta antibodies, we now document the co-occurrence of AMY immunoreactivity (IR) with amyloid beta-peptide (Abeta) in the large majority of plaques in AD brain. AMY IR was detected in many compacted plaques, whereas its co-localization with early, diffuse Abeta deposits was rare. AMY IR overlapped considerably or fully with Abeta and, in more severely affected AD brains, decorated the periphery of some plaques. In a temporal series of 29 Down syndrome (DS) brains from patients aged 12 to 73 years, the earliest AMY IR was detected in some plaques at age 15, following the earliest appearance of Abeta plaques (age 12 years), and then accrued within a subset of Abeta deposits, namely, the more spherical, compacted plaques. Brains from DS patients 29 years and older showed AMY staining in many Abeta plaques, as seen in AD. Brains from eight monkeys aged 17 to 34 years and thirty APP transgenic mice aged 8 to 20 months showed Abeta IR but no AMY IR. We conclude that AMY IR represents an amyloid-associated antigen that co-deposits in most but not all Abeta plaques in AD and DS and that accumulation of the AMY antigen follows Abeta deposition in plaques.     

Killing of Aspergillus fumigatus by alveolar macrophages is mediated by reactive oxidant intermediates

Phagocytosis and mechanisms of killing of Aspergillus fumigatus conidia by murine alveolar macrophages (AM), which are the main phagocytic cells of the innate immunity of the lung, were investigated. Engulfment of conidia by murine AM lasts 2 h. Killing of A. fumigatus conidia by AM begins after 6 h of phagocytosis. Swelling of the conidia inside the AM is a prerequisite for killing of conidia. The contributions of NADPH oxidase and inducible nitric oxide synthase to the conidicidal activity of AM were studied using AM from OF1, wild-type and congenic p47phox(-/-) 129Sv, and wild-type and congenic iNOS(-/-) C57BL/6 mice. AM from p47phox(-/-) mice were unable to kill A. fumigatus conidia. Inhibitors of NADPH oxidase that decreased the production of reactive oxidant intermediates inhibited the killing of A. fumigatus without altering the phagocytosis rate. In contrast to NADPH oxidase, nitric oxide synthase does not play a role in killing of conidia. Corticosteroids did not alter the internalization of conidia by AM but did inhibit the production of reactive oxidant intermediates and the killing of A. fumigatus conidia by AM. Impairment of production of reactive oxidant intermediates by corticosteroids is responsible for the development of invasive aspergillosis in immunosuppressed mice.     

Immunological characterization of a gammadelta T-cell stimulatory ligand on autologous monocytes

Bovine gammadelta T cells are stimulated to proliferate by autologous monocytes. This is referred to as the autologous mixed leucocyte reaction (AMLR). It has been shown previously that the stimulatory component is constitutively expressed on the monocyte plasma membrane and is a protein or has a protein moiety. Here we showed that gammadelta T-cell responses to the monocytes requires interaction with the T-cell receptor because Fab1 fragments of a monoclonal antibody (mAb) that reacts with the delta chain of the T-cell receptor blocked proliferation in the AMLR. Monocyte molecules involved in stimulation were also characterized further by biochemical and immunological methods. A mAb, named M5, was generated by immunizing mice with bovine monocytes and shown to block the ability of monocytes to stimulate in the AMLR. Treatment of monocytes or monocyte membranes with high salt, chelating agents or phospholipase C did not affect their ability to stimulate gammadelta T-cell proliferation or reactivity with mAb M5 indicating the ability of monocytes to stimulate does not involve peripheral membrane components or a glycosyl-phosphatidylinsositol (GPI)-anchored components. Hence it was concluded that the stimulation occurred as a result of intergral membrane proteins including that recognized by mAb M5. The ligand for mAb M5 was on all bovine monocytes and to a lower level on granulocytes but not on lymphocytes. MAb M5 also reacted with sheep monocytes but not with human monocytes or murine macrophages, in agreement with a previous reports that sheep monocytes but not human or mouse mononuclear phagocytes have the capacity to stimulate bovine gammadelta T cells in in vitro cultures. The level of expression of the M5 ligand was not altered by gamma-irradiation or culture of monocytes with lipopolysaccharide but it was decreased following culture with interferon-gamma-containing cell culture supernatants.     

Skeletal muscle contractility is preserved in COPD patients with normal fat‐free mass

Aim: Peripheral muscle dysfunction often occurs in patients with chronic obstructive pulmonary disease (COPD). The muscle dysfunction may be caused by a loss of force‐generating capacity, resulting from a loss of muscle mass, as well as by other alterations in contractile properties of skeletal muscle. Methods: The maximal isometric voluntary strength and fatigability were determined in hand‐grip and quadriceps muscles from nine male COPD patients (FEV₁ 30–50% predicted) and control subjects matched for fat‐free mass (FFM), physical activity level and age. Contractile properties and fatigability of the quadriceps muscle were also studied with electrically evoked isometric contractions. Results: The maximal voluntary force (MVC) and fatigability of the handgrip muscle did not differ between the COPD patients and control subjects. Also the MVC of the quadriceps muscle and the rate of force rise, contraction time, force–frequency relationship and fatigability, as determined with electrically evoked contractions, were similar in patients with COPD and control subjects. Conclusion: Skeletal muscle strength, contractile properties and fatigability are preserved in patients with moderate COPD and a normal FFM and activity level. This suggests that skeletal muscle dysfunction does not take place during moderate COPD until cachexia and/or a decline in physical activity occur.     

Response to a hepatitis B polypeptide vaccine in micelle form in a young adult population

Polypeptide micelles with relative molecular weights of 25,000 (p25) and 30,000 (gp30) daltons were prepared from native 22-nm hepatitis B surface antigen (HBsAg) particles. This p25/gp30 complex was alum-adsorbed, and three dosage levels (20 micrograms, 4 micrograms, and 0.8 micrograms) were administered at 0, 1, and 6 months to 51 human volunteers. Local and systemic reactions were clinically insignificant, and all vaccinees seroconverted, regardless of dose. As anticipated, antibody responses diminished as the dosage was reduced. Seroconversion rates and geometric mean antibody levels for the 20 micrograms dosage group were significantly better than those observed with a commercial vaccine and were comparable to those achieved after immunization with 40 micrograms of the intact 22-nm particles used to prepare the polypeptides. By 2 weeks, an anti-HBs response was elicited in 80% of the group receiving 20 micrograms of the polypeptide vaccine. This rapid response to immunization may be particularly beneficial for postexposure prophylaxis where the early development of immunity is advantageous.     

Inhibition of adhesion of enterotoxigenic Escherichia coli cells expressing F17 fimbriae to small intestinal mucus and brush-border membranes of young calves

Enterotoxigenic Escherichia coli strains expressing F17 fimbriae bind to the intestinal mucosa of young calves. F17 fimbriae recognize receptors present in the mucus layer and the brush-border membranes from duodenum, jejunum and ileum. The adhesion of E. coli F17 can be inhibited by several glycoproteins. Adhesion is also inhibited by pretreatment of mucus and brush-border membranes with sodium metaperiodate. The use of glycoconjugates as potential adhesion-blockers is further discussed.     

Optimal heparin surface concentration and antithrombin binding capacity as evaluated with human non-anticoagulated blood in vitro

Contact between blood and a biomaterial surface takes place in many applications and is known to activate the coagulation and complement systems. Heparin surface coatings have been shown to reduce blood activation upon contact with artificial surfaces. To establish the optimal heparin surface concentration, blood was incubated in a tubing loop model at 37 degrees C. The tubing was coated with different surface concentrations of heparin and rotated at three different velocities. We demonstrate that the blood compatibility of a surface with regard to coagulation, complement, and platelet activation can be improved by increasing the heparin surface concentration in the 6-12 pmol antithrombin/cm2 concentration interval. The binding of factor H is not influenced by the increased heparin surface concentration, suggesting that this factor is not the primary regulator of complement on heparin surfaces. In addition, the heparin coating has no effect on the complement activation that occurs on gas surfaces in extracorporeal circuits.     

Inhibitory processes in adults with persistent childhood onset ADHD

The theory that attention-deficit/hyperactivity disorder (ADHD) stems from a deficit in an executive behavioral inhibition process has been little studied in adults, where the validity of ADHD is in debate. This study examined, in high-functioning young adults with persistent ADHD and a control group, 2 leading measures of inhibitory control: the antisaccad task and the negative priming task. ADHD adults showed weakened ability to effortfully stop a refle ve or anticipated oculomotor response but had normal ability to automatically suppress irrelevant information. Results suggest that an inhibitory deficit in ADHD is confined to effortful inhibition of motor response, that antisaccade and negative priming tasks index distinct inhibition systems, and that persistence of ADHD symptoms into adulthood is associated with persistence of executive motor inhibition deficits.