Potassium-argon ages from the galapagos islands

Potassium-argon ages of eight volcanic rocks from some of the geologically oldest flows exposed in the Galápagos Archipelago indicate that the Galápagos Islands have a probable maximum age of 3 million years. Rocks from six islands were dated; the oldest are from Española (3.2 +/- 0.2), Sante Fe (2.7 +/- 0.1), and Plazas (4.2 +/- 1.8 million years). The new data suggest that the Galápagos Islands are younger than previously supposed on the basis of marine magnetic anomaly dating, but they are older than most previously dated rocks from the Galápagos.

Asthma clinic attendance improves quality of life of Jamaican asthmatic children and their parents

BACKGROUND

With the increasing incidence of paediatric asthma, there has been a corresponding increase in the physical, emotional and financial burden. This has led to a greater interest in determining the impact of asthma and its treatment on many aspects of patient functioning and wellbeing.

AIM

To assess the usefulness of the Asthma Clinic established in Jamaica in 1997 by ascertaining whether there has been improvement in quality of life of children and care-givers who attend the clinic.

METHODS

The quality of life of patients and their parents/care-givers before attending the Asthma Clinic of Bustamante Hospital for Children in Kingston, Jamaica was compared with that of 1 year afterwards. Parents or guardians were interviewed using the Pediatric Asthma Quality of Life Questionnaire which consists of three domains [symptoms (ten questions), emotional (eight questions) and activity (five questions)] and the Pediatric Asthma Caregiver's Quality of life Questionnaire which consist of two domains [emotional (nine questions) and activity (four questions)].

RESULTS

Quality of life improved in patients and their parents/care-givers in all domains.

CONCLUSION

Attendance at an asthma clinic in Jamaica improved the quality of life of asthmatic children and their parents/care-givers.

Maternal and foetal outcomes in pregnant patients with active lupus nephritis

The objective of this study was to determine the impact of lupus nephritis disease activity on maternal and foetal outcomes in pregnant patients with systemic lupus erythematosus (SLE). Medical records of all pregnant patients with SLE treated at our institution between 1976 and 2007 were reviewed. All patients met American College of Rheumatology classification criteria for SLE. Demographic data, history of lupus nephritis, nephritis disease activity and maternal and foetal outcomes of pregnancy were abstracted. Active lupus nephritis was defined as the presence of proteinuria >0.5 g/day and/or active urinary sediment with or without an elevation in serum creatinine (Cr). Quiescent lupus nephritis was confirmed in the presence of proteinuria <0.5 mg/day and inactive urinary sediment. We identified 58 patients with 90 pregnancies. Compared with pregnancies in SLE patients without renal involvement (n = 47), pregnancies in patients with active lupus nephritis (n = 23) were associated with a higher incidence of maternal complications (57% vs 11%, P < 0.001), whereas those with quiescent lupus nephritis (n = 20) were not (35% vs 11%, P = 0.10). Women with active lupus nephritis were more likely to deliver preterm than women without lupus nephritis, median of 34 weeks vs 40 gestational weeks, respectively (P = 0.002) and were more likely to suffer foetal loss (35% vs 9%, P = 0.031). Active, but not quiescent, lupus nephritis during pregnancy is associated with a higher incidence of maternal and foetal complications compared with pregnancies in SLE patients without renal involvement.

Quality parameters for alpaca (Vicugna pacos) semen are affected by semen collection procedure

Artificial insemination (AI) is poorly developed in camelids owing to the difficulty in collecting high quality semen and the highly viscous nature of the semen. Semen collected by artificial vagina (AV) is often of low quality and must be improved before any further development of AI technology can occur. The present study investigated the effects of adding a cervix-like stricture to the AV, presence of females, collecting semen into Androhep, skim-milk or Tris diluents, and catalase supplementation (0, 100, 200 or 600 units/ml) of Tris diluent on alpaca semen quality parameters. The addition of a cervix-like stricture increased mating length (p < 0.05), whilst the presence of females during semen collection did not improve semen quality parameters (p > 0.05). Collection of semen into Tris diluent improved sperm motility (58.0 +/- 11.9%) compared with the control (34.0 +/- 10.8%; p < 0.05), Androhep (33.5 +/- 10.7%) and skim-milk diluents (28.2 +/- 10.4%). Semen viscosity was reduced by collection into Androhep (4.6 +/- 1.7 mm) and skim-milk diluents (3.6 +/- 1.3 mm) compared with Tris diluent (5.7 +/- 2.1 mm) and no collection medium (9.3 +/- 3.5 mm; p < 0.05). Tris diluent supplemented with 100, 200 or 600 units/ml catalase increased semen viscosity (5.0 +/- 3.2 and 4.9 +/- 3.2 mm). Collection of alpaca semen by AV into Tris diluent increased semen quality facilitating further development of AI technology in alpacas.

Nuclear charge radius of 8He

The root-mean-square (rms) nuclear charge radius of 8He, the most neutron-rich of all particle-stable nuclei, has been determined for the first time to be 1.93(3) fm. In addition, the rms charge radius of 6He was measured to be 2.068(11) fm, in excellent agreement with a previous result. The significant reduction in charge radius from 6He to 8He is an indication of the change in the correlations of the excess neutrons and is consistent with the 8He neutron halo structure. The experiment was based on laser spectroscopy of individual helium atoms cooled and confined in a magneto-optical trap. Charge radii were extracted from the measured isotope shifts with the help of precision atomic theory calculations.

Laser trapping of 225Ra and 226Ra with repumping by room-temperature blackbody radiation

We have demonstrated Zeeman slowing and capture of neutral 225Ra and 226Ra atoms in a magneto-optical trap. The intercombination transition 1S0-->3P1 is the only quasicycling transition in radium and was used for laser-cooling and trapping. Repumping along the 3D1-->1P1 transition extended the lifetime of the trap from milliseconds to seconds. Room-temperature blackbody radiation was demonstrated to provide repumping from the metastable 3P0 level. We measured the isotope shift and hyperfine splittings on the 3D1-->1P1 transition with the laser-cooled atoms, and set a limit on the lifetime of the 3D1 level based on the measured blackbody repumping rate. Laser-cooled and trapped radium is an attractive system for studying fundamental symmetries.

The protease allergen Der p 1 cleaves cell surface DC-SIGN and DC-SIGNR: experimental analysis of in silico substrate identification and implications in allergic responses

BACKGROUND

The cysteine protease Der p 1 from the house dust mite Dermatophagoides pteronyssinus is one of the most potent allergens known. An attractive mechanism for a component of Der p 1 allergenicity lies in its ability to cleave key regulatory molecules from leucocyte surfaces, subverting cellular function and driving abnormal immunoglobulin E (IgE) responses.

OBJECTIVE

Although CD23, CD25 and CD40 have already been identified as major Der p 1 targets, other significant substrates may also exist.

METHODS

To investigate this, knowledge of the proteolytic properties of Der p 1 was used to perform in silico digestion of human dendritic cell surface proteins, using the prediction of protease specificity (PoPS) bioinformatics tool, in conjunction with cellular in vitro analysis and cleavage site determination.

RESULTS

Targets identified included DC-SIGN and DC-SIGNR, two C-type lectins implicated mostly in pathogen trafficking. Treatment of positively expressing cells with Der p 1 led to loss of detectable surface DC-SIGN and DC-SIGNR. Digestion of purified soluble recombinant DC-SIGN and DC-SIGNR, followed by N-terminal sequencing and MALDI mass spectrometry, indicated in each case one major cleavage site and several minor sites, the former correlating well with Der p 1 enzymology and the folded state of the substrate proteins. Loss of DC-SIGN from the cell surface led to reduced binding of intracellular adhesion molecule-3, an endogenous DC-SIGN ligand expressed on naïve T cells which is thought to be involved in T-helper type 1 cytokine signalling.

CONCLUSION

These data provide evidence of lectin involvement in the initiation of the allergic response and the value of using genome-wide in silico digestion tools.

Thermal beam of metastable krypton atoms produced by optical excitation

A room-temperature beam of krypton atoms in the metastable 5s[3/2]2 level is demonstrated via an optical excitation method. A Kr-discharge lamp is used to produce vacuum ultraviolet photons at 124 nm for the first-step excitation from the ground level 4p6 1S0 to the 5s[3/2]1 level. An 819 nm Ti:sapphire laser is used for the second-step excitation from 5s[3/2]1 to 5s[3/2]2 followed by a spontaneous decay to the 5s[3/2]2 metastable level. A metastable atomic beam with an angular flux density of 3 x 10(14) s(-1) sr(-1) is achieved at the total gas flow rate of 0.01 cm3/s at STP (or 3 x 10(17) at./s). The dependences of the flux on the gas flow rate, laser power, and lamp parameters are investigated.

Comparison of extent of tau pathology in patients with frontotemporal dementia with Parkinsonism linked to chromosome 17 (FTDP-17), frontotemporal lobar degeneration with Pick bodies and early onset Alzheimer's disease

In order to gain insight into the pathogenesis of frontotemporal lobar degeneration (FTLD), the mean tau load in frontal cortex was compared in 34 patients with frontotemporal dementia linked to chromosome 17 (FTDP-17) with 12 different mutations in the tau gene (MAPT), 11 patients with sporadic FTLD with Pick bodies and 25 patients with early onset Alzheimer's disease (EOAD). Tau load was determined, as percentage of tissue occupied by stained product, by image analysis of immunohistochemically stained sections using the phospho-dependent antibodies AT8, AT100 and AT180. With AT8 and AT180 antibodies, the amount of tau was significantly (P < 0.001 in each instance) less than that in EOAD for both FTDP-17 (8.5% and 10.0% respectively) and sporadic FTLD with Pick bodies (16.1% and 10.0% respectively). With AT100, the amount of tau detected in FTDP-17 was 54% (P < 0.001) of that detected in EOAD, but no tau was detected in sporadic FTLD with Pick bodies using this particular antibody. The amount of insoluble tau deposited within the brain in FTDP-17 did not depend in any systematic way upon where the MAPT mutation was topographically located within the gene, or on the physiological or structural change generated by the mutation, regardless of which anti-tau antibody was used. Not only does the amount of tau deposited in the brain differ between the three disorders, but the pattern of phosphorylation of tau also varies according to disease. These findings raise important questions relating to the role of aggregated tau in neurodegeneration - whether this represents an adaptive response which promotes the survival of neurones, or whether it is a detrimental change that directly, or indirectly, brings about the demize of the affected cell.