T-cell sensitisation to hepatitis B virus surface antigens

The present study was conducted to explore the immunity to hepatitis B surface antigens (HBsAg) of ad and ay subtypes at the cellular level among adult individuals. Peripheral blood mononuclear cells (PBMCs) obtained from acute hepatitis B virus (HBV) infected patients, chronic HBV infected patients, recovered subjects from HBV infection and uninfected vaccinated controls were stimulated with HBsAg ad and HBsAg ay subtypes in vitro. Stimulated PBMCs were incubated in CO(2) for production of interferon-gamma (IFN-gamma), which was measured from the supernatant of cultured PBMCs by an in-house ELISA technique. The mean +/- SE of IFN-gamma levels produced by PBMCs in response to HBsAg ad among the acute, chronic, recovered and control groups were 282.5+/-134.51 pg/ml, 307.45+/-94.84 pg/ml, 915.62+/-170.80 pg/ml and 511.67+/-161.22 pg/ml respectively, while on stimulation by HBsAg ay, the levels were 246.25+/-103.50 pg/ml, 374.70+/-104.02 pg/ml, 1040 +/-140.76 pg/ml and 465.83+/-166.26 pg/ml respectively among the above mentioned groups. The results of this study showed that PBMCs were non-responsive to stimulation by both HBsAg ad and HBsAg ay subtypes in acute and chronic patients with HBV infection. The recovered group responded significantly to both subtypes of HBsAg and the control group did not. The study indicates that although the patients with acute and chronic HBV infection showed weak or no IFN-gamma response to the HBsAg, subjects showed strong IFN-gamma response to the surface antigens on recovery from HBV infection.

A comparison of immunohistochemical and silver staining methods for the detection of diffuse plaques in the aged canine brain

Plaques and amyloid angiopathy represent frequent findings in the aging canine brain, whereas neuritic (senile) plaques and neurofibrillary tangles, the hallmark of Alzheimer's disease in humans, have only rarely been described in this species. Most studies on canine age-related CNS changes have used the modified (mod.) Bielschowsky method. Therefore, it remains to be determined, whether results obtained represent species-specific age-related changes or are due to the use of inappropriate methods. Consequently, the aim of this study was to compare the usefulness of various methods for the detection of age-related changes in the canine CNS. In a preliminary study, 130 brains from dogs between 1 month and 18 years of age were screened for the presence of A-beta protein using a monoclonal antibody against the beta-amyloid peptide. Thereafter, 30 brains of aged dogs, 10-18 years of age, out of the 130, were comparatively investigated by immunohistochemistry and silver stains such as the method of Campbell-Switzer, Reusche, Gallyas, modified (mod.) Bielschowsky and mod. Bodian as well as the Congo red-stain. Vascular amyloid angiopathy, plaques and A-beta protein deposits in the hippocampus/dentate gyrus were an age-dependent process starting at the age of 8 years and increased in a linear fashion with age. In contrast, plaque density did not rise in a similar age-related fashion in aged dogs. Moreover, great individual variations were observed in aged animals. Immunohistology was by far the most sensitive method for detection of diffuse plaques and amyloid angiopathy, followed by the Campbell-Switzer, Reusche, mod. Bielschowsky, and mod. Bodian technique. Neurofibrillary tangles and Congo red positive neuritic plaques were not found with any method. Immunohistochemically, two plaque types, both resembling diffuse human plaques, occurring in the superficial or deep cortical layers, were detected. Cluster analysis suggested the presence of three subgroups such as aged dogs with a low, medium and high number of plaques. Summarized, detection of plaques depends strongly upon the method used and the aging canine brain displays diffuse plaques and amyloid angiopathy but lacks neurofibrillary tangles and classic/neuritic and Congo red positive plaques. Cluster analysis indicated, that genetic factors might be important as predisposition for the development of diffuse plaques in dogs. The observed findings substantiate previous observations, that the canine brain represents an important model to study the pathogenesis of diffuse plaques and amyloid angiopathy in the absence of other Alzheimer disease characteristic lesions.

Human subtelomere structure and variation

Work towards completion of the human reference genome sequence has revealed a great deal of complexity and plasticity in human subtelomeric regions. The highly variable subtelomeric repeat regions are filled with recently shuffled genomic segments, many of which contain sequences matching transcripts and transcript fragments; the rapid duplication and combinatorial evolution of these regions has generated an extremely diverse set of subtelomeric alleles in the human species, the complexity and potential significance of which is only beginning to be understood. This review summarizes recent progress in analyzing human subtelomeric sequence assemblies and large-scale variation in human subtelomere regions.

Recruitment of sperm donors: the Newcastle-upon-Tyne experience 1994–2003

BACKGROUND

The demand for sperm donors has continued despite the introduction of ICSI. This study was undertaken in the light of impending changes in donor anonymity laws to evaluate the recruitment process of sperm donors.

METHODS

Retrospective analysis of 1101 potential sperm donors in a tertiary referral centre between January 1994 and August 2003. The main outcome measures were to determine the demographic details, recruitment rate and reasons for rejection of donors.

RESULTS

The majority of the applicants were aged <36 years (88.07%), students (54.88%), without a partner (53.47%), unmarried (85.38%) and without proven fecundity (78.67%). Only 3.63% of the applicants were released as donors, 30.79% defaulted, whilst 64.48% were rejected. The most common reason for rejection was suboptimal semen quality (85.07%). Over the years, the numbers of the applicants and released donors have declined significantly. The overall clinical pregnancy rate from donor sperm during this period was 23.52%.

CONCLUSIONS

In this successful anonymous sperm donor programme only a small proportion of the applicants are released as donors. The significant decline in released sperm donors coupled with the potential effects of loss of donor anonymity means that new strategies for sperm donor recruitment are urgently required.

Antimicrobial activity of chitosan against vibrios from freshwater prawn Macrobrachium rosenbergii larval rearing systems

Chitosan is a biocompatible and biodegradable natural polymer with established antimicrobial properties against specific microorganisms. The present study demonstrates its antibacterial activity against 48 isolates of Vibrio species from prawn larval rearing systems. The antibacterial activity had a positive correlation with the concentration of chitosan. This work opens up avenues for using chitosan as a prophylactic biopolymer for protecting prawn larvae from vibriosis.

A Superconducting Magnet UCN Trap for Precise Neutron Lifetime Measurements

Finite-element methods along with Monte Carlo simulations were used to design a magnetic storage device for ultracold neutrons (UCN) to measure their lifetime. A setup was determined which should make it possible to confine UCN with negligible losses and detect the protons emerging from β-decay with high efficiency: stacked superconducting solenoids create the magnetic storage field, an electrostatic extraction field inside the storage volume assures high proton collection efficiency. Alongside with the optimization of the magnetic and electrostatic design, the properties of the trap were investigated through extensive Monte Carlo simulation.

First Ever Storage of Ultracold Neutrons in a Magnetic Trap Made of Permanent Magnets

Further improvement in the accuracy of any neutron lifetime experiment by means of ultracold neutrons (UCN) in material bottles is limited due to unavoidable systematic effects when the UCN are reflected from the walls. However, such effects can be excluded in principle if magnetic trapping of UCN is used. The storage of UCN in a small magnetic trap made of permanent magnets was demonstrated for the first time ever. The measured storage time in this feasibility study was (882 ± 16) s. At this level of accuracy no depolarization was observed.

First measurement of the transverse spin asymmetries of the deuteron in semi-inclusive deep inelastic scattering

First measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized 6LiD target are presented. The data were taken in 2002 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. The Collins asymmetry turns out to be compatible with zero, as does the measured Sivers asymmetry within the present statistical errors.

CHHIPS (Controlling Hypertension and Hypotension Immediately Post-Stroke) Pilot Trial: rationale and design

RATIONALE

High and low blood pressure (BP) levels are common following acute stroke, with up to 60% of patients being hypertensive (SBP > 160 mmHg) and nearly 20% having relative hypotension (SBP < or = 140 mmHg), within the first few hours of ictus, both conditions being associated with an adverse prognosis. At present, the optimum management of blood pressure in the immediate post-stroke period is unclear.

OBJECTIVE

The primary aim of the Controlling Hypertension and Hypotension Immediately Post-Stroke (CHHIPS) Pilot Trial is to assess whether hypertension and relative hypotension, manipulated therapeutically in the first 24 h following acute stroke, affects short-term outcome measures.

DESIGN

The CHHIPS Pilot Trial is a UK based multi-centre, randomized, double-blind, placebo-controlled, titrated dose trial.

SETTING

Acute stroke and medical units in teaching and district general hospitals, in the UK.

PATIENTS

The CHHIPS Pilot Study aims to recruit 2050 patients, with clinically suspected stroke, confirmed by brain imaging, who have no compelling indication or contraindication for BP manipulation.

STUDY OUTCOMES

The primary outcome measure will be the effects of acute pressor therapy (initiated < or = 12 h from stroke onset) or depressor therapy (started < or = 24 h post-ictus) on death and dependency at 14 days post-stroke. Secondary outcome measures will include the influence of therapy on early neurological deterioration, the effectiveness of treatment in manipulating BP levels, the influence of time to treatment and stroke type on response and a cost-effectiveness analysis.

Docosahexaenoic acid restores endothelial function in children with hyperlipidemia: results from the EARLY study

OBJECTIVE

The primary objective of this study was to determine whether the National Cholesterol Education Program Step II (NCEP-II) diet or supplementation with docosahexaenoic acid (DHA) with the diet, affects endothelial function in children with familial hypercholesterolemia (FH) or the phenotype of familial combined hyperlipidemia (FCH). As secondary endpoints, the influence of diet and DHA supplementation on lipid profiles as well as biomarkers for oxidative stress and inflammation, and asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, were all evaluated.

METHODS

In a double-blind, placebo-controlled, randomized, crossover study design, 20 children (ages 9-19 years) with FH (n = 12) and FCH (n = 8) received nutritional counseling based on the National Cholesterol Education Program Step II (NCEP-II) and food guide pyramid dietary guidelines for 6 weeks. They were then randomly assigned to supplementation with docosahexaenoic acid (DHA 1.2 g/d) or placebo for 6 weeks, followed by a washout phase of 6 weeks and crossover phase of 6 weeks while continuing the NCEP-II diet. Endothelium-dependent flow-mediated dilation (FMD) of the brachial artery was determined by high-resolution ultrasound. Plasma levels of total cholesterol, triglycerides and lipoprotein classes (LDL, HDL, VLDL) were measured by ultracentrifugation and enzymatic methods, plasma F2 isoprostanes by gas chromatography/mass spectrometry, urinary 8-OH-2' deoxyguanosine by liquid chromatography, high sensitivity C-reactive protein by immunonephelometry and ADMA by liquid chromatography.

RESULTS

FMD increased significantly after DHA supplementation compared to baseline (p < 0.001), diet alone (p < 0.002), placebo (p < 0.012) and washout (p < 0.001) phases of the study without affecting biomarkers for oxidative stress, inflammation or ADMA. DHA supplementation was associated with increased levels of total cholesterol (p < 0.01), LDL- and HDL cholesterol concentrations (p < 0.001) compared to the NCEP-II diet.

CONCLUSION

This study demonstrates that DHA supplementation restores endothelial-dependent FMD in hyperlipidemic children. The endothelium may thus be a therapeutic target for DHA. This is consistent with a hypothesis of increasing NO bioavailability, with the potential for preventing the progression of early coronary heart disease in high-risk children.

Interferon-gamma (IFN-gamma) response to different hepatitis B virus antigens in hepatitis B virus infection

The IFN-gamma levels in serum and cultured supernatant of peripheral blood mononuclear cells (PBMCs) were compared after stimulation by HBsAg ad, HBsAg ay and HBcAg among 3 groups of subjects i.e. patients with acute HBV infection, patients with chronic HBV infection and subjects recovered from HBV infection. Uninfected vaccinated group was taken as control. Serum and PBMCs were obtained from 38 individuals between 18-50 years of age. PBMCs were separated from heparinised blood by Ficoll-Hypaque density gradient centrifugation technique and cultured in CO2 incubator after stimulation by HBV surface and core antigens. IFN-gamma concentration was measured in serum and culture supernatant of PBMCs by an in-house ELISA technique. The mean serum IFN-gamma levels in acute, chronic, recovered and control groups were 88 pg/ml, 96.6 pg/ml, 155 pg/ml and 205 pg/ml respectively. On stimulation by HBsAg ad, IFN-gamma levels in cultured PBMCs of the above mentioned groups were 282.50 pg/ml, 307.45 pg/ml, 915.62 pg/ml and 511.67 pg/ml respectively, while in the same group on HBsAg ay stimulation, IFN-gamma levels were 246.25 pg/ml, 374.70 pg/ml, 1040 pg/ml and 465.83 pg/ml respectively. On stimulation by HBcAg, the IFN-gamma levels were 875 pg/ml, 128.50 pg/ml, 905 pg/ml and 235.33 pg/ml respectively in the acute, chronic, recovered and control groups. When compared with serum, significantly higher levels of IFN-gamma in cultured supernatant of PBMCs were observed after stimulation by HBsAg ad and HBsAg ay subtype in cases of chronic (p<0.05) and recovered groups (p<0.01 and p<0.001 respectively). However, no statistically significant difference of IFN-gamma level was observed between serum and PBMCs amongst the acute and control groups when stimulated by either of the HBsAg subtypes or HBcAg. In the recovered group, IFN-gamma levels produced by PBMCs after stimulation by HBcAg were significantly higher than that of serum (p<0.01). The study concludes that on subsequent exposure, PBMCs of the recovered group produces higher levels of IFN-gamma in response to different hepatitis B antigens. This response perhaps is able to protect individuals who are unable to develop anti-HBs.