Expression of the H-subunit and L-subunit of ferritin in bone marrow macrophages and cells of the erythron during cellular immune activation.

BACKGROUND: The expression of the two types of ferritin subunits, the H-subunit and L-subunit, has been shown to be differentially regulated by cytokines. The primary aim of the present study was to quantitatively measure the expression of the H-subunit and L-subunit of ferritin in bone marrow macrophages and cells of the erythron in patients with chronic T-helper cell type-1 immune stimulation. METHODS: The expression of the H-subunit and L-subunit of ferritin in bone marrow macrophages and cells of the erythron was quantitatively evaluated by post-embedding immunolocalisation with immunogold transmission electron microscopy. RESULTS: The present study showed up-regulation of the H-subunit of ferritin in the bone marrow macrophage in patients with pronounced cellular immune activation (94.7±37.3 counts/µm(2); n=31 vs 72.4±34.0 counts/µm(2); n=13, p-value=0.037). CONCLUSION: This supports a possible role for H-subunit rich ferritins in the hypoferraemia of chronic disease.

Pro- and anti-inflammatory cytokines during immune stimulation: modulation of iron status and red blood cell profile.

Forty-eight patients were subdivided according to C-reactive protein (CRP) levels, resulting in 19 patients with normal (2.8 ± 2.8 mg/L) and 29 with elevated (82.2 ± 76.2 mg/L) CRP levels. The elevated CRP group had iron and red blood cell (RBC) profiles characteristic of chronic immune stimulation (CIS), and the normal CRP group, profiles of true iron deficiency. Normal relationships between storage iron, bioavailable iron, and RBC indices were absent in the elevated CRP group-implying the role of iron as major determinant of the RBC profile to be diminished during CIS. The elevated CRP group had significant increases in proinflammatory cytokines (INF-γ, TNF-α, Il-1ß, Il-6, and Il-8). Anti-inflammatory cytokine levels were normal, except for Il-10, supporting previous indications that Il-10 contributes to reducing bioavailable iron. Regression analysis suggested decreases in transferrin to be related to increases in Il-8 and an increase in ferritin to be related to a decrease in Il-12 levels. TGF-ß levels were positively related to transferrin and negatively to ferritin.

Short-term fatty acid effects on adipocyte glucose uptake: mechanistic insights.

The modulation of insulin sensitivity in visceral fat tissue could be important in the treatment of Type 2 diabetes mellitus. Selected fatty acids may impact on insulin-stimulated and basal glucose uptake in adipocytes, thus isolated rat epididymal adipocytes were exposed to 100 microM oleic, arachidonic, eicosapentaenoic, docosahexaenoic or stearic acids and insulin (15 nM) or vehicle for 30 min. Glucose uptake was quantified by measuring uptake of 3H-deoxyglucose/mg adipocyte protein/min. Where appropriate, inhibitors were included to elucidate the mechanisms involved. In this model, insulin stimulated glucose uptake with 62+/-7%. All fatty acids tested, except for stearic acid, depressed insulin-stimulated glucose uptake by an average of 33+/-4.2%. On the other hand, all fatty acids tested except stearic and arachidonic acids, stimulated basal glucose uptake with an average of 34+/-8.1%. Inhibitor studies showed the involvement of prostaglandins, lipoxins, protein kinase C and tyrosine kinase in these processes.

Ferritin and ferritin isoforms II: protection against uncontrolled cellular proliferation, oxidative damage and inflammatory processes.

Ferritin is a major iron storage protein involved in the regulation of iron availability. Each ferritin molecule comprises 24 subunits. Various combinations of H-subunits and L-subunits make up the 24-subunit protein structure and these ferritin isoforms differ in their H-subunit to L-subunit ratio, as well as in their metabolic properties. Ferritin is an acute-phase protein and its expression is up-regulated in conditions such as uncontrolled cellular proliferation, in any condition marked by excessive production of toxic oxygen radicals, and by infectious and inflammatory processes. Under such conditions ferritin up-regulation is predominantly stimulated by increased reactive oxygen radical production and by cytokines. The major function of ferritin in these conditions is to reduce the bio-availability of iron in order to stem uncontrolled cellular proliferation and excessive production of reactive oxygen radicals. Ferritin is not, however, indiscriminately up-regulated in these conditions as a marked shift towards a predominance in H-subunit rich ferritins occurs. Preliminary indications are that, while the L-subunit primarily fulfils the conventional iron storage role, the H-subunit functions primarily as rapid regulator of iron availability, and perhaps indirectly as regulator of other cellular processes. It is suggested that the optimum differential expression of the two subunits differ for different cells and under different conditions and that the expression of appropriate isoferritins offers protection against uncontrolled cellular proliferation, oxidative stress and against side effects of infectious and inflammatory conditions.

Ferritin and ferritin isoforms I: Structure-function relationships, synthesis, degradation and secretion.

Ferritin is the intracellular protein responsible for the sequestration, storage and release of iron. Ferritin can accumulate up to 4500 iron atoms as a ferrihydrite mineral in a protein shell and releases these iron atoms when there is an increase in the cell's need for bioavailable iron. The ferritin protein shell consists of 24 protein subunits of two types, the H-subunit and the L-subunit. These ferritin subunits perform different functions in the mineralization process of iron. The ferritin protein shell can exist as various combinations of these two subunit types, giving rise to heteropolymers or isoferritins. Isoferritins are functionally distinct and characteristic populations of isoferritins are found depending on the type of cell, the proliferation status of the cell and the presence of disease. The synthesis of ferritin is regulated both transcriptionally and translationally. Translation of ferritin subunit mRNA is increased or decreased, depending on the labile iron pool and is controlled by an iron-responsive element present in the 5'-untranslated region of the ferritin subunit mRNA. The transcription of the genes for the ferritin subunits is controlled by hormones and cytokines, which can result in a change in the pool of translatable mRNA. The levels of intracellular ferritin are determined by the balance between synthesis and degradation. Degradation of ferritin in the cytosol results in complete release of iron, while degradation in secondary lysosomes results in the formation of haemosiderin and protection against iron toxicity. The majority of ferritin is found in the cytosol. However, ferritin with slightly different properties can also be found in organelles such as nuclei and mitochondria. Most of the ferritin produced intracellularly is harnessed for the regulation of iron bioavailability; however, some of the ferritin is secreted and internalized by other cells. In addition to the regulation of iron bioavailability ferritin may contribute to the control of myelopoiesis and immunological responses.

Report : the Student Health Services at University of Pretoria from 2000 to 2005

The University of Pretoria's Student Health Services provides free; voluntary; family-medicine-orientated health services with an emphasis on offering preventative medicine and health education to enrolled students. Students are examined and/or educated by skilled personnel familiar with the University's environment and demands. Apart from the family medicine services; the Student Health Services also educates students concerning contraception and sexually-transmitted diseases; carries out HIV/AIDS counselling and provides a comprehensive dietetic service. During the period 2000 to 2005 the percentage of students visiting the Student Health Services; of the total number of students enrolled at the University; remained almost constant at 12.5. A large percentage of the students making use of these services do belong to a medical aid and it is estimated that during the past six years the University of Pretoria has subsidised an amount of about R2.4 million towards the medical costs of students belonging to a medical aid

Intracellular free calcium in the neutrophils of maintenance haemodialysis patients.

Chronic renal failure has on occasion been referred to as a state of calcium toxicity. The aim of this study was to investigate the status of intracellular free Ca2+ in the neutrophils of chronic renal failure patients on maintenance haemodialysis treatment. Factors previously suggested to influence intracellular free Ca2+ were investigated including PTH levels, oxidative stress and recombinant human erythropoietin administration. The study involved 14 chronic renal failure patients on the haemodialysis programme of the Pretoria Academic hospital. Intracellular free Ca2+ and transmembrane Ca2+ fluxes were investigated by fluorescence spectrophotometry. Increases above control values were found in intracellular free Ca2+ (P-value 0.0242) and in the transmembrane Ca2+ flux upon fMLP stimulation (P-value 0.0002). The results showed significant differences in intracellular free Ca2+ between patients on rHuEPO and patients not on rHuEPO. The apparently rHuEPO-induced increase in intracellular free Ca2+ persisted in the presence of calcium channel blockers. No overt indications of oxidative stress could be detected by the antioxidant vitamin levels. It is concluded that factors other than those associated with uraemia, such as rHuEPO administration, might contribute to the often reported increase in intracellular free Ca2+ in these patients. Further studies to investigate the relationship between intracellular free Ca2+, rHuEPO and calcium channel blockers are suggested.

Red blood cell fatty acid profile of chronic renal failure patients receiving maintenance haemodialysis treatment.

The fatty acid profile of chronic renal failure (CRF) patients on maintenance haemodialysis treatment (MHT) is abnormal and results point towards an essential fatty acid (EFA) deficiency. However, controversies still exist as to which of the essential fatty acids (EFAs) or EFA-products are decreased. In this study, the results of a comprehensive analysis of the fatty acids, performed on the red blood cells of 14 CRF patients on MHT, are presented. The red blood cell membrane fatty acids determined in this study include a range of saturated fatty acids (SFAs), mono-unsaturated fatty acids (MUFAs) and poly-unsaturated fatty acids (PUFAs). Results confirmed the suggested presence of an essential fatty acid deficiency in CRF patients on MHT. It showed the total content of the n-6 fatty acids (31.66 +/- 3.21 vs 34.67 +/- 2.05), as well as the total content of the PUFAs (37.22 +/- 4.08 vs 40.93 +/- 2.35), to be significantly decreased. The total MUFA content was, in contrast, significantly increased (16.87 +/- 0.91 vs 15.49 +/- 1.18). The EFA deficiency profile seen in this study points towards that of a chronic inflammatory condition. This is borne out by the fact that all three precursors of the eicosanoids--the mediators of various inflammatory and immune responses--were reduced in the presence of an increase in MUFAs as well as SFAs. The possibility of the fatty acid profile of CRF patients on MHT being that of a chronic inflammatory condition is supported by the fact that continuous complement-dependent and complement-independent immune activation, due to bio-incompatibility between blood cells and the dialysis membranes, is known to occur during the dialysis process.

A pulsed DC electric field affects P2-purinergic receptor functions by altering the ATP levels in in vitro and in vivo systems.

Recently it was shown that extracellular ATP, acting through purinergic receptors, has many physiological functions, including opening of Ca(2+)-ion channels, activation and mediation of signal transduction mechanisms as well as activation of the pain sensation. Since electrical stimulation is also known to affect many signal transduction processes as well as the alleviation of pain, we hypothesized that electric stimulation may affect the extracellular release of ATP. We investigated the effects of a small DC electric field (10(1)--10(2) V m(-1) range and with frequencies below 150 Hz) on the release of ATP in vitro (HeLa cells), and on the levels of ATP in vivo (the plasma of healthy volunteers). In HeLa cells ATP release was increased 50 fold, while the total amount of ATP in the cells was increased by 163%. In the plasma a significant decrease (P<0.05) in ATP concentration was seen after electrical stimulation, in all the volunteers. The small DC electric field also affected the cAMP signal transduction system in vitro (HeLa cells and human lymphocytes) and in vivo (human plasma). Decreased levels of cAMP (P<0.05) were seen in HeLa cells and increased levels of cAMP (P<0.05) in isolated human lymphocytes. The cAMP levels in the plasma of the electrically treated volunteers were lower than control values. These results show that the frequency, waveform and signal strength of the applied electric field are suitable for effecting measurable changes on signal transduction in vitro and in vivo.

Peribulbar anesthesia. A prospective statistical analysis of the efficacy and predictability of bupivacaine and a lignocaine/bupivacaine mixture.

The object of this trial was to determine the efficacy in peribulbar anesthesia of bupivacaine 0.5%, 0.75%, and a combination of bupivacaine 0.5% and lignocaine 2% in equal parts. Fifty-one and 50 patients in random order were injected with 0.5% and 0.75% bupivacaine, respectively, and another 50 patients with the lignocaine/bupivacaine mixture. The results were recorded and all data were statistically analyzed. We concluded that the peribulbar route with the agents used in this trial was not a successful technique. Our criterion for a successful block, i.e., akinesia, was not achieved in more than 54% of cases.

[A study of job satisfaction of nurses of the RSA (South Africa Nurses' Association)]. / 'n ondersoek na die werksbevrediging by die verpleegkundiges van die RSA.

The purpose of this study was to determine whether changes had occurred in the work satisfaction of nursing services after the establishment of private initiative in health care due to the deregulation program currently conducted by the government. In a survey conducted in the latter part of 1988 700 questionnaires were sent out of which 213 were returned which gives a response of 30.43 percent. The analysis was based on this data. The attitudes of the members of the nursing services ranged from antipathy to lively enthusiasm. It was, however, clear from the response that there exists a strong negative view amongst the nursing profession regarding remuneration, communication, training and promotion. These are tendencies that can harm the profession as a whole on the long run and should therefore receive special managerial attention. Recommendations include market related remuneration, continued nursing training, and planned career paths, as well as an appeal that only minimum admission requirements should be accepted as preconditions to training in order to cope with the growing Third World demands on health care services.