Glucans are fungal cell wall glucose polymers that are released into the blood of infected patients. The role of glucans in infection is unknown. We examined serum glucan and cytokine levels in intensive care unit (ICU) patients with infections. There was an inverse correlation (p<0.001) between serum glucan levels and interleukin (IL)-2), IL-4, tumor necrosis factorα (TNFα) and granulocyte macrophage-colony stimulating factor (GM-CSF) levels in infected ICU patients. The correlation between serum cytokines and serum glucan was only observed at glucan concentrations <40 pg/ml. No change was observed at serum glucan levels of >40 pg/ml. There was no correlation between serum glucan levels and systemic levels of IL-1β, IL-5, IL-6, IL-8, IL-10 or IFNγ. Interestingly, blood borne glucans did not suppress systemic cytokine levels in infected ICU patients, instead they were maintained at control levels. We conclude that circulating glucans may prevent cytokine upregulation in response to infection. This may represent an adaptive response to septic injury.

Experimental studies of nephrotoxic nephritis in animals have demonstrated many of the underlying pathogenetic mechanisms involved in human glomerulonephritis. The first part of this thesis reviews the literature with regard to the factors and mechanisms responsible for the causation of glomerulonephritis and those factors which determine severity and allow for its persistence. In order to study these mechanisms, a reproducible model of nephrotoxic nephritis (NTN) in rabbits was established. This disease is produced by the intravenous injection of nephrotoxic serum, raised in sheep, containing antibodies to rabbit glomerular basement membrane. In a second group of experiments, the induction of an acute phase response in rabbits by the subcutaneous injection of a local irritant was studied. It was characterised by changes in C-reactive protein (CRP), the third component of complement (C3), fibrinogen and polymorphonuclear leucocytes (PMN' s), however renal function and renal histology were not affected in any way. When the so called heterologous phase of NTN in rabbits was induced during maximal acute phase stimulation, it did not result in enhancement of injury when compared to unstimulated rabbits. A similar situation was found during 7 the autologous phase, where a superimposed acute phase stimulus again did not cause enhancement of injury. Despite the fact that CRP has been shown to localize in injured tissue under certain circumstances, it did not fix in the kidneys of rabbits with induced NTN, nor in human kidneys affected by a variety of glomerulonephritides. The reasons for the variation in severity of disease during the autologous phase were analysed. Rabbits which developed severe glomerulonephritis during· the autologous phase of NTN characteristically produced high titres of rabbit anti-sheep antibody early in the disease when compared to those which did not develop injury, even though they might ultimately have developed the same titre of antibodies. One of the major determinants of injury appears to have been the rate at which antibody bound to the glomerular basement membrane (GBM). Studies during the heterologous phase confirmed this impression when it was shown that nephrotoxic globulin (NTG) given slowly, produced less injury than when the same amount was infused fast. This observation also suggested that the effector function of immunoglobulin decays much more rapidly than was previously thought. Finally, a mechanism of "protection" from injury by circulating antibody was shown by the phenomenon of "saturation" of available antibody binding sites on the 8 glomerular basement membrane which appeared to limit the deposition of further circulating antibody thus preventing further damage. These studies have advanced the understanding of human glomerulonephritis by illustrating how variation in immune responsiveness may contribute to the development of disease. They suggest that something inherent in infections, other than merely an acute phase response, is responsible for infection induced relapse in certain cases of allergic renal disease. By demonstrating a mechanism of “protection" from the effect of circulating antibodies, these studies suggest that therapy directed towards blocking of available antigenic sites on the human glomerular basement membrane, may become a therapeutic reality.

Methods currently used to determine iron bioavailability have disadvantages for both the subjects and researchers involved. One safe and simple method that needs further evaluation, the serum iron absorption method, involves an initial blood drawing, dosage s of iron, and blood drawings taken at intervals thereafter. Generally, the rise in serum iron or area under the curve is used to determine iron uptake. Two experiments were conducted using the serum iron absorption method in an effort to improve the utility of this method for the measurement of iron bioavailability. With this effort in mind, an equation adjusting for dose of iron (0.5-8 mg) and blood volume was used to estimate serum iron absorption and allow for adequate comparisons of other iron absorption data obtained with this method and others. One very significant result was that low serum ferritin was found to be a predictor of high serum estimated iron absorption (SEIA). Similarly, low serum ferritin levels were also highly correlated to iron absorption when radioiron methods were used. In Experiment I, college-aged women (n=11) with low serum ferritin levels (average 11 ng/ml) participated in four serum iron trials in which four iron sources were used as iron dosages. Ferrous sulfate in orange juice (2.2 mg iron), ground beef (0.62 mg iron), cereal (6.6 mg iron), and ground beef and cereal together (3.6 mg iron) were used. Comparisons were made between the results obtained using this serum iron absorption data and other radioiron absorption data for similar iron sources, and the results were quite similar to iron absorption levels reported in the literature. In Experiment I, the ferrous sulfate (40%) and ground beef treatments (46%) had the highest serum estimated iron absorption (SEIA) and the cereal/ground beef (5%) and cereal treatments (3%) had significantly less. Experiment II involved 28 college-aged women who participated in four serum iron absorption trials. For these four trials the iron dose was the same (2 mg iron as ferrous sulfate in orange juice). However, pre-trial supplements containing either (1) 30 mg iron, 60 mg ascorbic acid, (2) 30 mg iron, no ascorbic acid, (3) no iron, 60 mg ascorbic acid, or (4) a placebo were given (one per day) on each of the three days prior to the weekly serum iron absorption trials. During each pre-trial supplementation period, three daily diet records were kept by subjects to determine if the previous intake of nutrients (from food or pre-trial supplements) influenced the outcome of the serum iron absorption trial. Pre-trial supplementation of 30 mg iron, no ascorbic acid caused a significantly lower SEIA. Dietary nutrients did not cause a significant effect on SEIA. Mean SEIA following combined iron supplements was lower (p=0.081) 16% vs. 23% following non-iron containing supplements. For this experiment, the SEIA was higher in subjects with low serum ferritin (20 ng/ml).

No description available.

This project was undertaken with the aim of developing a method for the assay of iodoamino acids in human serum. The iodoamino acids were separated by an ion exchange technique, and the resulting solutions analyzed for iodine using neutron activation analysis. This analytical system was applied to the analysis.of a number of serum samples from hypothyroid and hyperthyroid subjects. This allowed the division of each of these conditions into a number of classes in terms of the deviation of the individual iodoamino acid concentration from their normal ranges. / Thesis / Doctor of Philosophy (PhD)

No description available.

No description available.

The use of horizontal starch gel electrophoresis to separate gray squirrel blood serum was investigated. Three sources of variation in the techniques were identified: (1) minor variation within-run; (2) variation across-run; (3) variation due to the sampling technique. The frequencies of the most anodal bands of 42 gray squirrel blood serum protein electropherograms were compared among several woodlots using chi-square contingency tables. On the basis of these frequencies, no differences were found among the woodlot populations of gray squirrels examined in this study. / Master of Science

Seventeen males participated in an investigation comparing the effects of a three meal per day feeding pattern versus a six meal per day feeding pattern on a serum lipid profile. During a two week acclimation period three meals per day were consumed by all subjects. The subjects were then divided into two groups. Group I consumed three meals per day for six weeks while group II consumed six meals per day for the same amount of time. The two groups then reversed feeding patterns for an additional six week period. Subjects completed five four-day food records which were analyzed qualitatively. Three of the four-day food records for each subject were hand coded and computer processed for kilocalorie, total fat, saturated fat, and cholesterol intake. Mean intake of cholesterol was found to be within a desirable range. Mean intake of total fat and saturated fat were noted as exceeding desirable values. Blood samples were collected from each subject following a two week acclimation period and following each of the two six week feeding phases. The samples were analyzed for total cholesterol, triglyceride, LDL-cholesterol, and HDL-cholesterol levels. There was no statistically significant difference found between the consumption of three meals per day and six meals per day for the lipid parameters of total cholesterol and LDL-cholesterol. There was a significant decrease in triglyceride level with the six meal per day feeding pattern with one group but not the other. For both groups there was a significant difference (p < 0.05) in HDL-cholesterol levels between the six meals per day and the three meal per day feeding patterns. However, the findings were dissimilar in that for Group I the HDL-cholesterol was higher after the six meal pattern as opposed to the three meal pattern, and for Group II, the opposite was true. / M.S.

Background - The first 1000 days of life (from conception to two years of age) is a critical period of nutritional vulnerability, affecting lifelong health. Iron deficiency (ID) and iron deficiency anaemia (IDA) are considered major public health problems that adversely affect development and growth, impair immunity, and increase morbidity and mortality in infants. ID and IDA in sub-Saharan Africa can be attributed to poor dietary, socioeconomic and disease conditions. One of the major obstacles in determining the prevalence of ID, using serum ferritin (SF) as marker of iron status, is that it not only reflects the amount of iron that is stored in the body, but also functions as an acute phase reactant that is raised in the presence of infection or inflammation. Aim - We conducted a re-analysis of the International Research on Infant Supplementation (IRIS) study’s baseline data to determine a more accurate estimation of the ID prevalence in apparently healthy four to thirteen-month-old infants from rural KwaZulu-Natal while accounting for the effect of chronic and acute inflammation on SF. Study design and methods - A cross-sectional analysis was performed on the baseline data (192 infants) of the IRIS study that was conducted in 2000. Infants’ haemoglobin (Hb), SF, C-reactive protein (CRP) and alpha-1 glycoprotein (AGP) concentrations were interpreted to determine the prevalence of ID. Literature of the past four years served as a guide to compare the ID prevalence obtained from four methods that account for the influence of inflammation on SF concentrations, to a reference method that does not take inflammation into consideration, and to what was reported in the original IRIS study. Weight and recumbent length measurements were converted to z-scores to interpret subjects’ anthropometric nutritional status. Results - A high prevalence of inflammation (52.6%) was present, with 11.5% of the subjects being in the incubation, 17.2% in the early convalescent, and 24% in the late convalescent phase of inflammation. SF was significantly associated with both CRP (ß = 0.200; P = 0.005) and AGP (ß = 0.223; P = 0.002) when adjusting for gender and age. The IRIS study reported an ID prevalence of 18.3%, whereas the results of this study ranged from 17.2 to 52.1%. We derived an IDA prevalence that ranged from 12 to 24.5% according to the different methods. The prevalence of stunting [length-for-age Z-score <-2SD] was 12.5%; while 25.1% of infants were overweight/obese [weight-for-length z-score >2SD]. Conclusion - A double burden of malnutrition was evident from the high prevalence of both overweight and ID, together with inflammation. The disconcertingly large variance in ID prevalence observed between the different methods that were employed highlights that iron supplementation interventions to treat anaemia must be based upon accurate estimates of IDA prevalence, otherwise they pose an increased risk of adverse effects to susceptible, iron-replete, but anaemic infants. Given the detrimental consequences of ID, it is imperative that governments, health care providers and parents must act to prevent or treat ID and IDA among vulnerable infants. / MSc (Dietetics), North-West University, Potchefstroom Campus, 2014