Supported phospholipid bilayers as a platform for neural progenitor cell culture

Supported phospholipid bilayers constitute a biomimetic platform for cell behavior studies and a new approach to the design of cell culture substrates. Phosphocholine bilayers are resistant to cell attachment, but can be functionalized with bioactive molecules to promote specific cell interactions. Here, we explore phosphocholine bilayers, functionalized with the laminin-derived IKVAV pentamer, as substrates for attachment, growth, and differentiation of neural progenitor cells (AHPs). By varying peptide concentration (0-10%), we discovered a strongly nonlinear relationship between cell attachment and IKVAV concentration, with a threshold of 1% IKVAV required for attachment, and saturation in cell binding at 3% IKVAV. This behavior, together with the 10-fold reduction in cell attachment when using a jumbled peptide sequence, gives evidence for a specific interaction between IKVAV and its AHP cell-surface receptor. After 8 days in culture, the peptide-functionalized bilayers promoted a high degree of cell cluster formation. This is in contrast to the predominant monolayer growth, observed for these cells on the standard laminin coated growth substrates. The peptide-functionalized bilayer did not induce differentiation levels over those observed for the laminin coated substrates. These results are promising in that peptide-functionalized bilayers can allow attachment and growth of stem cells without induction of differentiation.

Is there a relationship between spontaneous GH secretion, anthropometric parameters and exercise capacity in healthy men over 50 years?

BACKGROUND

The use of growth hormone (GH) in deficient adults has already been demonstrated to result in several benefits regarding metabolic parameters, body composition and quality of life. Due to the similarities between GH deficiency in adults and the aging process, the concept of somatopause has emerged.

OBJECTIVES

Correlate the GH secretion profile in healthy men older than 50 years with anthropometric parameters and exercise capacity.

PATIENTS AND METHODS

Twenty-nine healthy male were selected, with a mean age of 57.9+/-4.2 years (range 50-66). After hospital admission, body mass index (BMI), body composition (fat mass) and abdominal circumference, 24-h GH profile, GH peak and basal IGF-I were evaluated, and all the patients underwent a treadmill stress testing to estimate exercise capacity with the Bruce protocol, with evaluation of the maximum oxygen peak, maximum heart rate and METs. All the results are shown as mean+/-Std deviation: BMI -26.5+/-4.9kg/m2, percent fat mass -27.1+/-6.2%, abdominal circumference -92.1+/-10.1cm, 24h GH profile -0.3+/-0.2ng/dl, peak GH -2.5+/-2.0ng/dl, IGF-I -202.4+/-72.4ng/dl, maximum oxygen peak -31.9+/-6.8L, maximum heart rate - 161.4+/-7.5 bpm and METs - 9.1+/-1.9. After regression analysis using the GH secretion profile (mean GH in 24h, spontaneous peak GH and basal IGF-I) as dependent variable, no correlations were found between these and the other evaluated parameters.

A novel cell force sensor for quantification of traction during cell spreading and contact guidance

In this work, we present a ridged, microfabricated, force sensor that can be used to investigate mechanical interactions between cells exhibiting contact guidance and the underlying cell culture substrate, and a proof-of-function evaluation of the force sensor performance. The substrates contain arrays of vertical pillars between solid ridges that were microfabricated in silicon wafers using photolithography and deep reactive ion etching. The spring constant of the pillars was measured by atomic force microscopy. For time-lapse experiments, cells were seeded on the pillared substrates and cultured in an on-stage incubator on a microscope equipped with reflected differential interference contrast optics. Endothelial cells (ECs) and fibroblasts were observed during attachment, spreading, and migration. Custom image analysis software was developed to resolve cell borders, cell alignment to the pillars and migration, displacements of individual pillars, and to quantify cell traction forces. Contact guidance classification was based on cell alignment and movement angles with respect to microfabricated ridges, as well as cell elongation. In initial investigations made with the ridged cell force sensor, we have observed contact guidance in ECs but not in fibroblast cells. A difference in maximal amplitude of mechanical forces was observed between a contact-guided and non-contact-guided, but mobile, EC. However, further experiments are required to determine the statistical significance of this observation. By chance, we observed another feature of cell behavior, namely a reversion of cell force direction. The direction of forces measured under rounded fibroblast cells changed from outwards during early cell attachment to inwards during further observation of the spreading phase. The range of forces measured under fibroblasts (up to 138 nN) was greater than that measured in EC (up to 57 nN), showing that the rigid silicon sensor is capable of resolving a large range of forces, and hence detection of differences in traction forces between cell types. These observations indicate proof-of-function of the ridged cell force sensor to induce contact guidance, and that the pillared cell force sensor constructed in rigid silicon has the necessary sensitivity to detect differences in traction force vectors between different cell phenotypes and morphologies.

Efavirenz and chronic neuropsychiatric symptoms: a cross-sectional case control study

OBJECTIVE

The aim of the study was to investigate symptoms of long-term central nervous system (CNS) toxicity in HIV-positive patients treated with efavirenz (EFV).

METHODS

We carried out a single-centre, cross-sectional case-control study comparing patients treated with EFV for at least 6 months with a matched control group. Self-administered, standardized questionnaires including the Depression, Anxiety and Stress Scales (DASS), the Cognitive Failures Questionnaire (CFQ) and a questionnaire on unusual dreams, insomnia, fatigue, dizziness, depersonalization and derealization were administered.

RESULTS

Data for 32 matched pairs were analysed. Significantly higher total stress scores (P=0.008) were found in the EFV group. Of the patients in this group, 19% also reported severe to extremely severe levels of stress (P=0.014), indicating increased difficulty in relaxing, and being more irritable, impatient, agitated and easily upset. Nineteen per cent of patients treated with EFV also reported severe levels of anxiety (P=0.059) as assessed with the DASS scale. This patient group also reported a higher rate of unusual dreams (P=0.049). No significant differences between groups were found for measures of cognitive impairments, fatigue, dizziness, derealization or depersonalization.

CONCLUSION

EFV-treated patients reported higher levels of severe stress and anxiety as well as a higher rate of unusual dreams than patients not treated with EFV. These differences may be an expression of persisting CNS side effects in patients who remain on EFV for a prolonged period.

Effects of nandrolone decanoate compared with placebo or testosterone on HIV-associated wasting

Objectives Current research is unclear about the most effective pharmacological agents for managing the loss of weight and fat-free mass common in HIV/AIDS. The aim of this study was to compare nandrolone decanoate with placebo and testosterone. Methods The study was a multicentre randomized double-blind placebo-controlled trial. Three hundred and three adult HIV-positive male patients with a weight loss of 5-15% in the last 12 months, or a body mass index of 17-19 kg/m(2), or a body cell mass/height ratio lower than 13.5 kg/m, were randomly assigned to receive nandrolone decanoate (150 mg), testosterone (250 mg) or placebo intramuscularly every 2 weeks for 12 weeks. Fat-free mass, weight, immune markers and perception of treatment were the main outcome measures. Results Treatment with nandrolone resulted in significantly greater increases in fat-free mass [mean increase 1.34 kg; 95% confidence interval (CI) 0.60; 2.08 kg] and in weight (mean increase 1.48 kg; 95% CI 0.82; 2.14 kg) compared with placebo. The mean increase in weight with nandrolone of 1.00 kg (95% CI 0.27; 1.74 kg) when compared with testosterone was significant, although the difference in fat free mass did not reach significance (mean increase 0.69 kg; 95% CI-0.13; 1.51 kg). Patient perception of benefit was significantly greater in the nandrolone group when compared with both the placebo and the testosterone groups. Conclusions Treatment with nandrolone decanoate increased body weight when compared with placebo and testosterone. Nandrolone decanoate treatment resulted in greater increases in fat-free mass than placebo and demonstrated a trend for a significant increase when compared with testosterone.

Ergonomic stressors and upper extremity musculoskeletal disorders in automobile manufacturing: a one year follow up study

AIMS

To estimate the one year cumulative incidence and persistence of upper extremity (UE) soft tissue disorders, in a fixed cohort of automotive manufacturing workers, and to quantify their associations with ergonomic exposures.

METHODS

At baseline and at follow up, cases of UE musculoskeletal disorders were determined by interviewer administered questionnaire and standardised physical examination of the upper extremities. The interview obtained new data on psychosocial strain and updated the medical and work histories. An index of exposure to ergonomic stressors, obtained at baseline interview, was the primary independent variable. Cumulative incidence and persistence of UE disorders (defined both by symptoms and by physical examination plus symptoms) were analysed in relation to baseline ergonomic exposures, adjusting for other covariates. The incidence of new disorders was modelled using multivariate proportional hazards regression among workers who were not cases in the first year and the prevalence on both occasions was modelled by repeated measures analysis.

RESULTS

A total of 820 workers (69% of eligible cohort members) was examined. Follow up varied slightly by department group but not by baseline exposure level or other characteristics. Among the non-cases at baseline, the cumulative incidence of UE disorders was 14% by symptoms and 12% by symptoms plus examination findings. These rates increased with index of physical exposures primarily among subjects who had the same jobs at follow up as at baseline. Increased exposure during follow up increased risk of incidence. The persistence of UE disorders from baseline to follow up examination was nearly 60% and somewhat associated with baseline exposure score.

CONCLUSIONS

These longitudinal results confirm the previous cross sectional associations of UE musculoskeletal disorders with exposure to combined ergonomic stressors. The exposure-response relation was similar for incident cases defined by symptoms alone and those confirmed by physical examination.

Quantitative assessment of the response of primary derived human osteoblasts and macrophages to a range of nanotopography surfaces in a single culture model in vitro

The effect of nanotopography on a range of Ti oxide surfaces was determined. Flat Ti, 3%, 19%, 30% and 43% topography densities of 110 nm high hemispherical protrusions were cultured in contact with primary derived human macrophages and osteoblasts in single culture models. Prior to introduction of the test substrate the phenotype and optimum conditions for in vitro cell culture were established. The cellular response was investigated and quantified by assessments of cytoskeletal development and orientation, viable cell adhesion, cytokine production and release and RT-PCR analysis of osteogenic markers. The tested nanotopographies did not have a statistically significant effect on viable cell adhesion and subsequent cytoskeletal formation. Surface chemistry was the dominant factor as established via incorporation of a tissue culture polystyrene, TCPS, control. The topography surfaces induced a release of chemotactic macrophage activation agents at 1 day in conjunction with stress fibre formation and a subsequent fibronectin network formation. Osteoblasts migrated away from the topography surfaces to the exposed TCPS within the wells during the 7-day period.

Chemically patterned, metal oxide based surfaces produced by photolithographic techniques for studying protein- and cell-surface interactions I: Microfabrication and surface characterization

Chemical patterns on smooth wafer substrates comprising areas with two different metals have been produced by vacuum metal deposition and photolithographic techniques. The combination of metals has been chosen from the series titanium (Ti), aluminium (Al), vanadium (V) and niobium (Nb), producing patterns (dots and stripes with dimensions of 50, 100 and 150 micrometer) with one of the metals as the background and with the second metal (foreground pattern) deposited on the background metal. The structure and chemical composition of the patterned surfaces were evaluated by scanning electron microscopy, X-ray photoelectron spectroscopy and imaging time-of-flight secondary-ion mass spectrometry. The surfaces proved to be geometrically well defined with the expected surface-chemical composition, i.e. a surface oxide (passive) film essentially composed of TiO(2),Al(2)O(3),V(2)O(5), or Nb(2)O(5). Ti/Ti patterned surfaces were produced as controls and found to show no chemical composition contrast. The surface roughness of the pattern was greater than that of the background by a factor of 2-3, but was still extremely smooth with Ra<2nm. The patterns serve as model surfaces for studying in vitro the behaviour of cells as well as the adsorption of serum proteins on different metal oxides, which will be reported in a companion paper. These surfaces can be used to compare and contrast the response of osteoblasts to Ti and other alloy components, such as Al, V, or Nb, which are used in load-bearing medical implants.

Calculating energy requirements for men with HIV/AIDS in the era of highly active antiretroviral therapy

OBJECTIVES

1. To determine if resting energy expenditure (REE) adjusted for body composition is elevated in HIV-positive males when compared with healthy controls in the era of highly active antiretroviral therapy. 2. To examine the accuracy of prediction equations for estimating REE in people with HIV. 3. To determine if REE adjusting for body composition is significantly different between those HIV-positive subjects reporting lipodystrophy (LD) or weight loss (>or=5%) and those who are weight stable when compared to controls.

DESIGN

Cross-sectional study.

SETTING

Tertiary referral hospital HIV unit and an outpatient clinic specializing in HIV care.

SUBJECTS

HIV-positive males (n=70) and healthy male controls (n=16).

METHODS

REE was measured using indirect calorimetry. Body composition was assessed using bioelectrical impedance analysis.

RESULTS

1. REE when adjusted for fat-free mass and fat mass using the general linear model (analysis of covariance) was greater in HIV-positive subjects than controls (7258+/-810 kJ, n=70 vs 6615+/-695 kJ, n=16, P<0.05). 2. The Harris and Benedict, Schofield, Cunningham and the two equations previously published by Melchior and colleagues in HIV-positive subjects all gave an estimate of REE significantly different from the measured REE in the HIV-positive subjects, therefore a new prediction equation was developed. The inability of the published equations to predict REE in the different HIV-positive subgroups reflected the heterogeneity in body composition. 3. REE adjusted for fat-free and fat mass was significantly greater in the both the HIV patients who were weight stable and those with lipodystrophy compared with the healthy controls.

CONCLUSION

REE is significantly higher in HIV-positive males when compared with healthy controls. Body composition abnormalities common in HIV render the use of standard prediction equations for estimating REE invalid. When measuring REE in HIV-positive males adjustment steps should include fat-free and fat mass.

Alberta law confining child prostitutes upheld

The Alberta Court of Queen's Bench has determined that the Alberta Protection of Children Involved in Prostitution Act is not in violation of the Constitution. This decision overturns the ruling of the Provincial Court, which held that the Act infringes the rights articulated in sections 7, 8, and 9 of the Charter.

Ontario Court of Justice dismisses police negligence case: HIV infection a factor

On 22 February 2001, the case of Chartier v Greaves was dismissed by the Ontario Superior Court of Justice.

Motion to strike claim dismissed in HIV defamation suit

On 23 April 2001, the Ontario Superior Court of Justice issued the first Canadian ruling on the issue of whether words inputing that a person is HIV-positive or has AIDS can be the basis of a defamation action per se, in the case of Serdar v Metroland Printing, Publishing and Distributing Ltd.