2,603 research outputs found
The association between levels of socio-economic status and fibrin network architecture in women aged between 35 and 44 years
ThesisProspective epidemiological studies from 1980 to 1989 accumulated evidence
of a possible relationship between cardiovascular disease and plasma
fibrinogen concentration. It was soon evident that raised fibrinogen levels,
causing hypercoagulable states, involve complex and multifactorial processes·.
Consequently it is important to realise that hypercoagulability is associated
with other risk factors of cardiovascular disease. This elevates the increasing
importance of studying the haemostatic variables together with these risk
factors.
It is suspected however, that not only fibrinogen concentration, but also the
quality of fibrin networks may contribute to coronary heart disease risk. It is
known that other modulating factors in blood also affect the network structures
as they are formed with otherwise constant fibrinogen and thrombin
concentrations. Previous research extensively studied modulating factors
such as albumin, glucose, smoking and diabetes.
Socially patterned accumulation of health capital and cardiovascular risk
begins in childhood. In the Whitehall II longitudinal study conducted by
Brunner, adult occupational position was inversely associated with fibrinogen,
other metabolic risk factors and risk factors like leisure time physical inactivity.
Childhood, social position was associated with adult fibrinogen levels. The objective of this study was to determine the association between fibrin
network architecture and socio-economic status in adult women. Three
groups of adult women representing different socio-economic backgrounds
were chosen randomly to voluntarily participate in the study. The study
groups consisted of 27 white women (employees of the TFS), 30 "urbanized"
black women (women living in an urbanized area for more than thirty years),
and 30 "less urbanized" black women (women living in an urbanized area for
less than thirty years).
Fasting blood samples were taken on the premises of the Technikon Free
State by a registered nurse and volunteers had medical examinations by a
registered general practitioner. Fibrin network architecture variables and
plasma fibrinogen were determined on fresh essentially platelet free plasma
by standardised laboratory techniques. Other metabolic variables were
performed on serum and full blood counts were performed on EDT A whole
blood using standardised laboratory techniques.
Results indicated that a association between socio-economic status and
haemostatic profiles do exist. Many of the differences in analytical variables
however, were expected and due to other relating factors such as ethnicity.
The mean fibrinogen level of the white group of women was 3.S4±0.24 gIL.
The group of black women defined as "less urbanized" displayed lower mean
fibrinogen levels (3.16±.0.19 gIL). In contrast, the levels of the "urbanized"
black women were much higher (4.04±0.22 gIL). However, these differences
were not significant. This confirms the effect of urbanization and thus socio-economic status on plasma fibrinogen levels. Small differences were
observed between network fibrin content and fibrinogen levels, and between
mass length ratio and fibrinogen levels in all three the groups. It was
unknown if these differences were static or in the process of development and
an indication of future tendencies. Except for total protein values no
significant differences were found between metabolic variables. This was
expected as very strict inclusion/exclusion criteria were used to ensure that all
volunteers were "apparently" healthy.
This study in a way contradicts the hypothesis that socio-economic class itself
may be the main cause of differences in some metabolic parameters from
individuals within different levels of socio-economic backgrounds seeing as
such strict exclusion criteria were used. It is believed that the factors related
to the different levels of socio-economic status, such as the prevalence of
tuberculosis, HIV, diabetes mellitus, hypercholesterolaemia, may play an
important role in the outcome of the health status of the individuals within
different levels of society. This study implies that the metabolic variables
associated with different levels of socio-economic status are not necessarily
associated with socio-economic class itself, but rather with the associated
factors related to the different levels of socio-economic status. The study
group was also very small which might have contributed to the lack of
significance between groups. This study emphasises the need for prospective
epidemiological trails to evaluate the true effect of socioeconomic variables
and associated conditions on metabolic risk factors
Production and quality aspects of rooibos tea and related products. A review
Use of the herbal tea, rooibos, made from the indigenous South African fynbos plant, Aspalathus linearis spp. linearis, has shown tremendous growth on the international markets since the 1990s. From a small beginning in 1904, solely depended on wild harvesting, the industry has developed out of the selected and cultivated Nortier type, leading to improved quality. Traditional rooibos is processed, entailing an oxidation („fermentation“) step, essential to develop the characteristic sweetish flavour and red-brown colour. Higher antioxidant levels for unfermented rooibos resulted in the development of green rooibos and extracts enriched in aspalathin, a potent antioxidant unique to rooibos. Major markets for rooibos extracts are ready-to-drink iced teas and cosmetic products
Troubleshooting Time-Dependent Density-Functional Theory for Photochemical Applications: Oxirane
The development of analytic-gradient methodology for excited states within
conventional time-dependent density-functional theory (TDDFT) would seem to
offer a relatively inexpensive alternative to better established
quantum-chemical approaches for the modeling of photochemical reactions.
However, even though TDDFT is formally exact, practical calculations involve
the use of approximate functionals, in particular the TDDFT adiabatic
approximation, whose use in photochemical applications must be further
validated. Here, we investigate the prototypical case of the symmetric CC ring
opening of oxirane. We demonstrate by direct comparison with the results of
high-quality quantum Monte Carlo calculations that, far from being an
approximation on TDDFT, the Tamm-Dancoff approximation (TDA) is a practical
necessity for avoiding triplet instabilities and singlet near instabilities,
thus helping maintain energetically reasonable excited-state potential energy
surfaces during bond breaking. Other difficulties one would encounter in
modeling oxirane photodynamics are pointed out but none of these is likely to
prevent a qualitatively correct TDDFT/TDA description of photochemistry in this
prototypical molecule.Comment: 19 pages, 17 figures, submitted to the Journal of Chemical Physic
Inhalation therapy during acute asthma : the role of a combined steroid and beta-stimulant preparation
CITATION: Joubert, J. R., Burger, G. & Shephard, E. 1985. Inhalation therapy during acute asthma : the role of a combined steroid and beta-stimulant preparation. South African Medical Journal, 68:381-384.The original publication is available at http://www.samj.org.zaA compound consisting of a β-stimulant, salbutamol (100 μg/puff), and a steroid, beclomethasone diproprionate (50 μg/puff), was studied to test the hypothesis that the corticosteroid could enhance the bronchodilator proporties of the β-stimulant during chronic asthma and simulated acute attacks (antigen challenge). Conventional doses (200 μg and 100 μg of salbutamol and beclomethasone respectively) were compared using a schedule which included a second administration 1 hour later. The results obtained on the baseline bronchial responsiveness of chronic asthmatics and during the delayed asthmatic response (simulated acute asthma) were similar. The compound was as effective as salbutamol alone but not more so. A significantly greater bronchodilator response was recorded in all patients after the second administration of both the compound and salbutamol alone. The practical advantages of having one rather than two inhalers are evident, but the appropriate application of this compound agent, probably in a prophylactic role, must be defined.Publisher’s versio
Computed tomography features of basal ganglia and periventricular calcifications in childhood
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Maceration Before and During Fermentation: Effect on Pinotage Wine Phenolic Composition, Total Antioxidant Capacity and Objective Colour Parameters
Low-temperature maceration treatments (1, 2 and 4 days at 10 and 15°C) before fermentation and juice/skin mixing treatments (punching-down, pumping-over and rotor action every hour and every 3 hours) duringfermentation were investigated in terms of their effects on Pinotage wine phenolic composition, total antioxidant capacity (TAC) and colour over three vintages (2000 to 2002). Results for pre-fermentation maceration were notconsistent between vintages. Very few significant differences in the phenolic content, TAC and objective colour parameters were observed between the control wines and wines subjected to different pre-fermentation macerationtreatments. Pre-fermentation maceration, especially at 15°C, resulted in wines with increased vitisin A content. Improvement of wine quality when using pre-fermentation maceration treatments at 10°C was noted previously, while no detrimental effect on the wine TAC was observed. The pumping-over treatment yielded wines with lower TAC and phenol content, as well as less favourable objective colour values, indicating that the punching-down or rotor treatment would be preferred. Although mixing at hourly intervals yielded a higher content of some phenolic compounds compared to the 3-hour interval mixing, mixing frequency did not affect the TAC of the wine. The objective colour parameters, h* and b*, were slightly lower at the higher mixing frequency in 2002 indicating a shift in the direction of a magenta hue
Changes in the Phenolic Composition and Antioxidant Activity of Pinotage, Cabernet Sauvignon, Chardonnay and Chenin blanc Wines During Bottle Ageing
The effect of bottle ageing on the antioxidant activity of Pinotage, Cabernet Sauvignon, Chardonnay and Chenin blanc wines, using the 2,2'-azino-di-(3-ethylbenzothialozine-sulphonic acid) radical cation (ABTS•+) and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH0) scavenging assays, was determined. Storage at 0°C, 15°C or 30°C for a period of 12 months resulted in a significant (p ≤ 0.05) decrease in both the total antioxidant activity (TAAAnTs and TAAoPPH) and the total phenol content of the wines. The antioxidant potency of the total phenols of most of the wines, which is a ratio of antioxidant activity to the total phenol content, also decreased. The total anthocyanins in the red wines decreased significantly (p ≤ 0.05) over 12 months except for storage at 0°C, while the flavanol content of the Pinotage, Cabernet Sauvignon and Chardonnay wines increased up to nine months storage with a subsequent decrease to 12 months. The flavonol content of all the wines decreased, while only minor changes in their hydroxycinnamate content were observed during the storage period. Understanding the complexity of these reactions may provide clues for stabilising especially red wines to preserve the antioxidant activity without losing the beneficial effects of colouring and flavour development during bottle ageing
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