Serum concentration and half-life of rifampicin after simultaneous oral administration of aminosalicylic acid or isoniazid

Summary Single oral doses of rifampicin (10 mg/kg body weight), p-aminosalicylic acid (0.2 g/kg), isoniazid (10 mg/kg), or rifampicin and either p-aminosalicylic acid or isoniazid, were given to 69 tuberculous patients with normal renal and hepatic function. Ten-fold interindividual differences were observed in the peak serum concentrations and half-lives of rifampicin; its half-life was reduced from 4.3 h after the first dose to 3.1 h after the third dose, possibly due to self-induction of its own metabolism. No effect on its serum concentration or half-life, nor on those of isoniazid, were found after simultaneous oral administration of the two drugs. After treatment with rifampicin and p-aminosalicylic acid, the peak serum level of the former was delayed from 2 to 4 h, it was reduced from 8.0 to 3.8 µg/ml, and the mean area under the serum concentration curve throughout the entire 8 h study period was also lowered by about half. Individual patients did not attain therapeutically effective peak serum concentrations of rifampicin if also treated withp-aminosalicylic acid. The interaction observed between the two drugs is probably due to impaired gastrointestinal absorption of rifampicin, either by alteration of its physico-chemical properties or by a decrease in the gastric emptying rate combined with more rapid intestinal transit. The combination of these two drugs is unsuitable for the routine chemotherapy of tuberculosis.     

Modelling the transport of ionizing radiation using the finite element method

Radiation therapy treatment planning is based on the calculation of the absorbed dose in the patient domain. For exact dose calculations, the solution of three coupled Boltzmann transport equations (BTEs) is needed to cover the transport of photons, electrons and positrons. In many situations, however, two coupled systems for photons and electrons are enough. The use of numerical methods in finding the exact solution of the unknown particle fluxes is necessary. In the stationary case, the BTE has six variables, three spatial, two directional and one energy variable. In this paper, we describe an approach in which the finite element method (FEM) is used to solve the six-dimensional problem. For the coupled photon-electron system, the variational formulation and the existence and uniqueness of the solution are derived. We simulate the solution of two coupled BTEs describing the travelling of photons and electrons in two spatial dimensions. The results are compared to Monte Carlo calculations with good agreement.     

Life after cancer in childhood: social adjustment and educational and vocational status of young-adult survivors

PURPOSE: To evaluate the long-term social effect of illness and its treatment on young-adult survivors of pediatric cancer by addressing a selection of general social adjustment criteria. METHODS: In a cross-sectional case-control study, 30 young-adult survivors of childhood cancer were compared with (1). controls with no history of serious illness, matched by sex, age, and geographic area of residence, and (2). general population norms on the subject of educational and vocational factors, habitation, family/partner relationships, parenthood, and leisure activities. RESULTS: The educational status of survivors was similar to that of controls, although a smaller proportion of the patients expressed concrete plans for future vocational or educational advancement. Survivors had less frequently entered higher education compared with general population norms. A longer duration of treatment was related to a lower estimated socioeconomic level, and poor psychological coping with the illness experience was associated with the fact that they were still living with their parents, a shorter education, and a lower socioeconomic level. CONCLUSIONS: The social, vocational, and educational adjustment of relapse-free survivors from childhood cancer appears as only moderately, if at all, negatively affected by the illness and treatment history. However, the treatment intensity and particularly the survivors' coping with their illness experience may influence their ability to achieve long-term social goals. These findings suggest that special attention should be given to matters concerning education and partner relationships at long-term follow-up of pediatric cancer patients.     

A method for assessing occupational dermal exposure to permanent hair dyes

Hairdressers have an increased risk of developing occupational skin diseases due to exposure to skin irritants and sensitizers. In the present work a method of assessing dermal exposure to permanent hair dyes was developed. The sampling performance characteristics of hand wash sampling with bag rinsing were studied for five hair dye compounds. The effect of residence time, sample load and different matrices were studied. Thirty volunteers were exposed to a reference solution of these compounds and to commercial hair dye products. The sampling efficiency after 5 min residence time was between 70 and 90% for the dye components in the hair dye products. Sampling efficiency decreases with increasing residence time, making the time of sampling an important factor. Hand wash sampling should be performed as soon as possible after the work task of interest. We conclude that the sampling efficiency is adequate for measurements of dermal exposure to permanent hair dyes. Hand wash sampling with bag rinsing is a useful tool for field studies of dermal exposure assessment in hairdressers.     

Estimated intake of milk fat is negatively associated with cardiovascular risk factors and does not increase the risk of a first acute myocardial infarction. A prospective case-control study

'Orujo' olive oil is obtained by chemical processes from the waste resulting from the mechanical extraction of virgin olive oil. The aim of the present study was to evaluate a new pharmacological property of two natural triterpenoids contained in olive oil, as vasodilatory agents, and to determine their mechanism of action. The two compounds studied were oleanolic acid and erythrodiol. The vasorelaxant effect induced by these pentacyclic triterpenoids was studied in isolated thoracic rat aorta. Oleanolic acid and erythrodiol, accumulatively added, showed vasorelaxant activities in aortic rings with endothelium pre-contracted by 10(-6) m-phenylephrine (maximum percentage of relaxation 86.38 (sem 2.89) and 73.53 (sem 6.01), respectively). They had almost no relaxant effect on depolarised or endothelium-denuded aortic segments. The relaxation was significantly attenuated by pre-treatment with the NO synthase inhibitor N(omega)-nitro-L-arginine-methylester (L-NAME; 3x10(-4) m). To characterise the involvement of endothelial factors, in addition to NO, arteries with endothelium were exposed to 10(-5) m-indomethacin (INDO), a cyclo-oxygenase inhibitor, or INDO plus L-NAME. INDO did not have any significant effect on the relaxant response of both compounds. The combination of L-NAME plus INDO only abolished the oleanolic acid-induced relaxation. The present results suggest that the mechanism of relaxation seems to be mainly mediated by the endothelial production of NO; however, other mechanisms cannot be excluded. It can be concluded that oleanolic acid and erythrodiol may have interesting therapeutic potential as new vasodilator drugs, thus protecting the cardiovascular system. Therefore, the intake of 'orujo' olive oil, as a source of these compounds, might be beneficial in this regard.     

A population-based study of anxiety as a precursor for depression in childhood and adolescence

Background  

Anxiety and depression co-occur in children and adolescents with anxiety commonly preceding depression. Although there is some evidence to suggest that the association between early anxiety and later depression is explained by a shared genetic aetiology, the contribution of environmental factors is less well examined and it is unknown whether anxiety itself is a phenotypic risk factor for later depression. These explanations of the association between early anxiety and later depression were evaluated.     

Spontaneous immortalization of clinically normal colon-derived fibroblasts from a familial adenomatous polyposis patient

Normal human diploid cells do not spontaneously immortalize in culture, but instead enter replicative senescence after a finite number of population doublings. Ablation of key checkpoint arrest or cancer-suppressor genes, through dominantly inherited germline mutation (p53+/-, Li-Fraumeni) or viral oncogene expression (SV40 large T, HPV16/18, and E6/E7) can lead to escape from senescence, additional doublings, and entrance into crisis phase, where immortal clones emerge at low frequency. In the vast majority of cases, telomerase is reactivated and telomeres are stabilized. Here we describe the spontaneous immortalization of clinically normal fibroblasts derived from colonic stroma of a familial adenomatous polyposis (FAP) patient. The preimmortal (C26C) and the spontaneously immortalized derivative (C26Ci) cells are heterozygous for a characterized germline mutation in exon 15 of the adenomatous polyposis coli gene. Immortalization was accompanied by spontaneous reactivation of endogenous telomerase and establishment of telomeres at presenescent lengths. Normal checkpoint behavior is retained and a diploid karyotype is maintained. These cells provide a valuable new addition to the limited number of spontaneously immortalized human cell types, particularly fibroblast cells, and will be useful in experimentally determining the functional pathways in neoplastic development and in the identification of potential molecular targets for cancer chemoprevention.     

Antibacterial peptides: basic facts and emerging concepts

Antibacterial peptides are the effector molecules of innate immunity. Generally they contain 15-45 amino acid residues and the net charge is positive. The cecropin type of linear peptides without cysteine were found first in insects, whilst the defensin type with three disulphide bridges were found in rabbit granulocytes. Now a database stores more than 800 sequences of antibacterial peptides and proteins from the animal and plant kingdoms. Generally, each species has 15-40 peptides made from genes, which code for only one precursor. The dominating targets are bacterial membranes and the killing reaction must be faster than the growth rate of the bacteria. Some antibacterial peptides are clearly multifunctional and an attempt to predict this property from the hydrophobicity of all amino acid side chains are given. Gene structures and biosynthesis are known both in the fruit fly Drosophila and several mammals. Humans need two classes of defensins and the cathelicidin-derived linear peptide LL-37. Clinical cases show that deficiencies in these peptides give severe symptoms. Examples given are morbus Kostmann and atopic allergy. Several antibacterial peptides are being developed as drugs.