Effects of hypoxia and nitric oxide on ferritin content of alveolar cells

Concentrations of ferritin in alveolar cells and on the alveolar surface are increased in patients with a variety of respiratory disorders. Ferritin synthesis by cells is modulated by iron content but is also influenced by stimuli other than iron. In this study we sought to determine whether in vitro exposure to hypoxia- or nitric oxide (NO)-induced ferritin accumulation or release by human alveolar macrophages (AMs) or a lung cancer-derived epithelial cell line (A549). Changes in cell content of iron and ferritin (L- and H-types), as well as ferritin content of cell supernatants, were determined after in vitro exposure to hypoxia (1% or 10% O(2), 18 hours) or the NO donor S-nitroso-N-acetylpenicillamine (SNAP, 0.01-1.0 mmol/L, 18 hours). Exposure to 1% O(2) increased ferritin content in both cell types (>fourfold increase; P <.005) without changing iron content. Treatment with SNAP increased ferritin content of A549 cells in a dose-dependent manner, whereas treatment of AMs decreased cellular iron and ferritin content and increased supernate ferritin content. Pretreatment of cells with N-acetylcysteine (500 micromol/L) reduced hypoxia-induced ferritin accumulation in alveolar cells and completely inhibited NO-induced ferritin accumulation in A549 cells. These findings indicate that exposure to 1% O(2)can increase ferritin content in alveolar cells, whereas NO can increase ferritin content (A549 cells) or decrease ferritin content (AMs).     

Cardiac care: 1. Interpretation of electrocardiogram rhythm strips

This is the first in a series of three papers that aim to explain the anatomy and physiology related to cardiac conductivity and to describe some common and less common arrhythmias that ward nurses may come across. This first paper examines the background to ECG monitoring, the anatomy and physiology of the heart and ECG recording and interpretation.     

Importance of the Therapeutic Products Act for the ENT practitioner

The Therapeutic Products Act controls therapeutic products and their fields of application, and classifies them legally. The present regulations on therapeutic products are based on a fundamental concept comprising basic demands, harmonized standards, agreement of the product attributes with the basic demands, and assessment of conformity. Therapeutic products (among which in vitro diagnostics are counted) must comply with definite regulations and are separated from medicines by their mode of action. In addition, therapeutic products must be subject to critical testing. The establishment, management, and use of therapeutic products are, with few exceptions, governed by the Regulations for the Use of Therapeutic Products. To avoid possible risks involved in the application of therapeutic products, a well-functioning system of registration is required, controlled by the Regulations on Therapeutic Products Safety.     

Factors influencing the choice to use modern natural family planning

A discrepancy exists between the interest in modern methods of natural family planning (NFP) and their actual use in developed countries. To explore reasons for this discrepancy, we analyzed data from a questionnaire administered to postpartum women in Berlin (n = 223) and Cracow (n = 233). Knowledge of NFP, past use of NFP and expected effects of abstinence on the partnership were independently associated with interest in using NFP, but not the choice to do so among those interested. Desire for future pregnancies, importance of religious belief and location in Cracow were independently associated with the choice to use NFP among those interested. Perceived accuracy of observation to identify the fertile time and acceptance of own body were independently associated with both interest in and choice to use NFP. Frequency of intercourse had no effect on interest. These results suggest that increased access and cultural support would likely lead to a higher prevalence of NFP use in developed countries.     

Dietary interactions influence the effects of bovine folate-binding protein on the bioavailability of tetrahydrofolates in rats

The newborns of mammals have a high folate demand, yet obtain adequate folate nutrition solely from their mothers' milk despite its low folate content. Milk folate is entirely bound by an excess of folate-binding protein (FBP), prompting speculation that FBP may affect the bioavailability of the limited folate supply. Previous research has shown that FBP-bound folic acid is more gradually absorbed, thereby reducing the peak plasma folate concentration and preventing loss into the urine. Natural folates are reduced derivatives of folic acid, with milk predominantly containing 5-methyltetrahydrofolate, yet little research has been carried out to determine the role of FBP in the bioavailability of reduced folates. We studied the effect of FBP on folate nutrition of rats in both single-dose and 4-wk feeding experiments. The effect of FBP was influenced by the presence of other milk components. FBP increased bioavailability of dietary folate when it was consumed with other whey proteins or with soluble casein. However, in the presence of acid-precipitated casein or a whey preparation enriched in lipids, bioavailability was decreased. These results highlight the difficulties of extrapolating from experimental results obtained using purified diets alone and of studying interactions among dietary components. They suggest that the addition of FBP-rich foods to folate-rich foods could enhance the bioavailability of natural folates, but that the outcome of such a combination would depend on interactions with other components of the diet.     

The role of cumulative physical work load in lumbar spine disease: risk factors for lumbar osteochondrosis and spondylosis associated with chronic complaints

OBJECTIVES—To investigate the relation with a case-control study between symptomatic osteochondrosis or spondylosis of the lumbar spine and cumulative occupational exposure to lifting or carrying and to working postures with extreme forward bending.
METHODS—From two practices and four clinics were recruited 229 male patients with radiographically confirmed osteochondrosis or spondylosis of the lumbar spine associated with chronic complaints. Of these 135 had additionally had acute lumbar disc herniation. A total of 197 control subjects was recruited: 107 subjects with anamnestic exclusion of lumbar spine disease were drawn as a random population control group and 90 patients admitted to hospital for urolithiasis who had no osteochondrosis or spondylosis of the lumbar spine radiographically were recruited as a hospital based control group. Data were gathered in a structured personal interview and analysed using logistic regression to control for age, region, nationality, and other diseases affecting the lumbar spine. To calculate cumulative forces to the lumbar spine over the entire working life, the Mainz-Dortmund dose model (MDD), which is based on an overproportional weighting of the lumbar disc compression force relative to the respective duration of the lifting process was applied with modifications: any objects weighing 5 kg were included in the calculation and no minimum daily exposure limits were established. Calculation of forces to the lumbar spine was based on self reported estimates of occupational lifting, trunk flexion, and duration.
RESULTS—For a lumbar spine dose >9×10⁶ Nh (Newton×hours), the risk of having radiographically confirmed osteochondrosis or spondylosis of the lumbar spine as measured by the odds ratio (OR) was 8.5 (95% confidence interval (95% CI) 4.1 to 17.5) compared with subjects with a load of 0 Nh. To avoid differential bias, forces to the lumbar spine were also calculated on the basis of an internal job exposure matrix based on the control subjects' exposure assessments for their respective job groups. Although ORs were lower with this approach, they remained significant.
CONCLUSIONS—The calculation of the sum of forces to the lumbar spine is a useful tool for risk assessment for symptomatic osteochondrosis or spondylosis of the lumbar spine. The results suggest that cumulative occupational exposure to lifting or carrying and extreme forward bending increases the risk for developing symptomatic osteochondrosis or spondylosis of the lumbar spine.


Keywords: case-control study; physical work load; lumbar osteochondrosis; lumbar spondylosis