Development of a web-based assessment tool that evaluates the meal situation when a child has a percutaneous endoscopic gastrostomy.

BACKGROUND: Children with cancer often suffer side effects from their treatment, for example nausea and vomiting, which can lead to malnutrition. If a child cannot eat orally, a percutaneous endoscopic gastrostomy (PEG) can improve his or her well-being, psychosocial development and growth by enabling the supply of nourishment and facilitating the administration of necessary medicines. Few data exist on children's comfort when using a PEG. The aim of this study was firstly to develop three versions of a web-based assessment tool in which children, families, and healthcare professionals would be able to register their observations and assessments for evaluating the meal situation when a child has a PEG and secondly to validate the content of the tool. METHODS: A qualitative design was chosen with purposive sampling of participants. Five children with cancer, five parents, five registered nurses and five paediatricians participated first in an interview and then in a member check of the web-based tool. The data were analysed with manifest qualitative content analysis. RESULTS: The results highlighted four categories of issues which needed to be revised in the web-based tool: words which were difficult for the participants to understand, items which contained several questions, items which needed to be split into more items to be answerable and the layout of the questionnaire. The web-based tool was revised according to the categories, and then a member check evaluated and finally confirmed the revisions. CONCLUSIONS: A web-based tool may be able to evaluate the meal situation when a child with cancer has a PEG. The tool may be able to detect early failures of the PEG, facilitating early action from the healthcare professionals in supporting the child and his or her parents in their care of the PEG. In the long run, this web-based tool may also be able to increase the quality of care of children living with a PEG.

Formation and repair of clustered damaged DNA sites in high LET irradiated cells.

PURPOSE: Radiation with high linear energy transfer (LET) produces clustering of DNA double-strand breaks (DSB) as well as non-DSB lesions. Heat-labile sites (HLS) are non-DSB lesions in irradiated cells that may convert into DSB at elevated temperature during preparation of naked DNA for electrophoretic assays and here we studied the initial formation and repair of these clustered damaged sites after irradiation with high LET ions. MATERIALS AND METHODS: Induction and repair of DSB were studied in normal human skin fibroblast (GM5758) after irradiation with accelerated carbon and nitrogen ions at an LET of 125 eV/nm. DNA fragmentation was analyzed by pulsed-field gel electrophoresis (PFGE) and by varying the lysis condition we could differentiate between prompt DSB and heat-released DSB. RESULTS: Before repair (t = 0 h), the 125 eV/nm ions produced a significant fraction of heat-released DSB, which appeared clustered on DNA fragments with sizes of 1 Mbp or less. These heat-released DSB increased the total number of DSB by 30-40%. This increase is similar to what has been found in low-LET irradiated cells, suggesting that the relative biological effectiveness (RBE) for DSB induction will not be largely affected by the lysis temperature. After 1-2 hours repair, a large fraction of DSB was still unrejoined but there was essentially no heat-released DSB present. CONCLUSIONS: These results suggest that high LET radiation, as low LET gamma radiation, induces a significant fraction of heat-labile sites which can be converted into DSB, and these heat-released DSB may affect both induction yields and estimates of repair.

Suppression of DNA-dependent protein kinase sensitize cells to radiation without affecting DSB repair.

Efficient and correct repair of DNA double-strand break (DSB) is critical for cell survival. Defects in the DNA repair may lead to cell death, genomic instability and development of cancer. The catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) is an essential component of the non-homologous end joining (NHEJ) which is the major DSB repair pathway in mammalian cells. In the present study, by using siRNA against DNA-PKcs in four human cell lines, we examined how low levels of DNA-PKcs affected cellular response to ionizing radiation. Decrease of DNA-PKcs levels by 80-95%, induced by siRNA treatment, lead to extreme radiosensitivity, similar to that seen in cells completely lacking DNA-PKcs and low levels of DNA-PKcs promoted cell accumulation in G2/M phase after irradiation and blocked progression of mitosis. Surprisingly, low levels of DNA-PKcs did not affect the repair capacity and the removal of 53BP1 or γ-H2AX foci and rejoining of DSB appeared normal. This was in strong contrast to cells completely lacking DNA-PKcs and cells treated with the DNA-PKcs inhibitor NU7441, in which DSB repair were severely compromised. This suggests that there are different mechanisms by which loss of DNA-PKcs functions can sensitize cells to ionizing radiation. Further, foci of phosphorylated DNA-PKcs (T2609 and S2056) co-localized with DSB and this was independent of the amount of DNA-PKcs but foci of DNA-PKcs was only seen in siRNA-treated cells. Our study emphasizes on the critical role of DNA-PKcs for maintaining survival after radiation exposure which is uncoupled from its essential function in DSB repair. This could have implications for the development of therapeutic strategies aiming to radiosensitize tumors by affecting the DNA-PKcs function.

The influence of AKT isoforms on radiation sensitivity and DNA repair in colon cancer cell lines.

In response to ionizing radiation, several signaling cascades in the cell are activated to repair the DNA breaks, prevent apoptosis, and keep the cells proliferating. AKT is important for survival and proliferation and may also be an activating factor for DNA-PKcs and MRE11, which are essential proteins in the DNA repair process. AKT (PKB) is hyperactivated in several cancers and is associated with resistance to radiotherapy and chemotherapy. There are three AKT isoforms (AKT1, AKT2, and AKT3) with different expression patterns and functions in several cancer tumors. The role of AKT isoforms has been investigated in relation to radiation response and their effects on DNA repair proteins (DNA-PKcs and MRE11) in colon cancer cell lines. The knockout of AKT1 and/or AKT2 affected the radiation sensitivity, and a deficiency of both isoforms impaired the rejoining of radiation-induced DNA double strand breaks. Importantly, the active/phosphorylated forms of AKT and DNA-PKcs associate and exposure to ionizing radiation causes an increase in this interaction. Moreover, an increased expression of both DNA-PKcs and MRE11 was observed when AKT expression was ablated, yet only DNA-PKcs expression influenced AKT phosphorylation. Taken together, these results demonstrate a role for both AKT1 and AKT2 in radiotherapy response in colon cancer cells involving DNA repair capacity through the nonhomologous end joining pathway, thus suggesting that AKT in combination with DNA-PKcs inhibition may be used for radiotherapy sensitizing strategies in colon cancer.

Expectant parents' experiences of parental education within the antenatal health service.

Being an expectant parent is a life changing event and it is something that most people will experience in their lifetime. Many people who are parents for the first time will participate in parenting education. Most of the previous studies associated with parenting education focus on subjects such as birth outcome and breastfeeding. The purpose of this study is to focus on the less investigated aspect of the parents' experience of participating in parenting education with Maternal Healthcare Services (MVC). A qualitative, phenomenological, hermeneutical method was selected to be used to analyze our findings and we used the statements of twenty participants to accumulate enough material to develop it into twelve sub-themes and five themes. The results of this study show that these expectant parents had few or no expectations of the parenting education that they were going to participate in. Generally speaking the parents seemed to be satisfied with the program. They described their reasons for participating as a chance to get together with other people in similar circumstances and to share information and they found a midwife to be a trustworthy professional person to confirm the information that was available to them from other sources.

Continuous positive airway pressure and surfactant.

Nasal continuous positive airway pressure (nCPAP) is an effective treatment of respiratory distress syndrome. Due to long-standing experience of early nCPAP as the primary respiratory support option in preterm infants, this approach is sometimes labeled 'the Scandinavian Model'. Mechanical ventilation is potentially harmful to the immature lungs and cohort studies have demonstrated that centers using more CPAP and less mechanical ventilation have reduced rates of bronchopulmonary dysplasia. However, there is a lack of evidence in the form of larger, randomized controlled trials to prove the superiority of either method. Surfactant is essential in the treatment of respiratory distress syndrome and has generally been reserved for infants on mechanical ventilation. With the development of INSURE (INtubation SURfactant Extubation), in which surfactant is administered during a brief intubation followed by immediate extubation, surfactant therapy can be given during nCPAP treatment further reducing need for mechanical ventilation. In this review the history, current knowledge and techniques of CPAP and surfactant are discussed.

Behavioral stress is affected by the mode of tube feeding in very low birth weight infants.

OBJECTIVE: To compare the effect of continuous versus bolus feeding on behavioral responses of stress in very low birth weight infants during early postnatal life. METHODS: In a randomized, controlled trial conducted at 3 neonatal units, 70 premature infants with gestational age 24 to 29 weeks and birth weight <1200 g were randomly assigned to 1 of 3 feeding methods: continuous nasogastric feeding, bolus nasogastric feeding, and bolus orogastric feeding. Behavioral responses were video recorded during feeding at 7 and 15 days of postnatal age and at 32 weeks of postmenstrual age. The odds ratio (OR) of manifest behavioral stress was calculated by means of logistic regression. RESULTS: A significantly higher risk of a behavioral stress response in bolus-fed infants compared with continuous-fed infants at 15 days of age was observed, [adjusted OR=4.1 (95% confidence interval: 1.1-15.4)]. A similar difference was observed at 32 weeks of postmenstrual age [adjusted OR=4.2 (95% confidence interval: 1.0-17.8)]. In addition, bolus-fed infants showed statistically significant higher need of behavioral and physiologic stabilization during feeding. DISCUSSION: This trial suggests that continuous feeding is associated with lower behavioral stress response as compared with bolus feeding among very low birth weight infants, in early postnatal life.

New crystal structures of human glutathione transferase A1-1 shed light on glutathione binding and the conformation of the C-terminal helix.

Human glutathione transferase A1-1 is a well studied enzyme, but despite a wealth of structural and biochemical data a number of aspects of its catalytic function are still poorly understood. Here, five new crystal structures of this enzyme are described that provide several insights. Firstly, the structure of a complex of the wild-type human enzyme with glutathione was determined for the first time at 2.0 angstroms resolution. This reveals that glutathione binds in the G site in a very similar fashion as the glutathione portion of substrate analogues in other structures and also that glutathione binding alone is sufficient to stabilize the C-terminal helix of the protein. Secondly, we have studied the complex with a decarboxylated glutathione conjugate that is known to dramatically decrease the activity of the enzyme. The T68E mutant of human glutathione transferase A1-1 recovers some of the activity that is lost with the decarboxylated glutathione, but our structures of this mutant show that none of the earlier explanations of this phenomenon are likely to be correct. Thirdly, and serendipitously, the apo structures also reveal the conformation of the crucial C-terminal region that is disordered in all previous apo structures. The C-terminal region can adopt an ordered helix-like structure even in the apo state, but shows a strong tendency to unwind. Different conformations of the C-terminal regions were observed in the apo states of the two monomers, which suggests that cooperativity could play a role in the activity of the enzyme.

The effects of food on the dissolution of poorly soluble drugs in human and in model small intestinal fluids.

PURPOSE: This study was conducted to determine the effect of food on drug solubility and dissolution rate in simulated and real human intestinal fluids (HIF). METHODS: Dissolution rate obtained via the rotating disk method and saturation solubility studies were carried out in fed and fasted state HIF, fed dog (DIF), and simulated (FeSSIF) intestinal fluid for six aprotic low solubility drugs. The intestinal fluids were characterized with respect to physical-chemical characteristics and contents. RESULTS: Fed HIF provided a 3.5- to 30-times higher solubility compared to fasted HIF and FeSSIF, whereas fed DIF corresponded well (difference of less than 30%) to fed HIF. The increased solubility of food could mainly be attributed to dietary lipids and bile acids. The dissolution rate was also 2 to 7 times higher in fed HIF than fasted HIF. This was well predicted by both DIF and FeSSIF (difference of less than 30%). CONCLUSIONS: Intestinal solubility is higher in fed state compared to fasted state. However, the dissolution rate does not increase to the same extent. Dog seems to be a good model for man with respect to dissolution in the small intestine after intake of a meal, whereas FeSSIF is a poorer means of determining intestinal saturation solubility in the fed state.

Vitamin D fails to prevent serum starvation- or staurosporine-induced apoptosis in human and rat osteosarcoma-derived cell lines.

Previous studies have suggested that 1,25(OH)2D3, the active form of vitamin D3, may increase the survival of bone-forming osteoblasts through an inhibition of apoptosis. On the other hand, vitamin D3 has also been shown to trigger apoptosis in human cancer cells, including osteosarcoma-derived cell lines. In the present study, we show that 1,25(OH)2D3 induces a time- and dose-dependent loss of cell viability in the rat osteosarcoma cell line, UMR-106, and the human osteosarcoma cell line, TE-85. We were unable, however, to detect nuclear condensation, phosphatidylserine externalization, or other typical signs of apoptosis in this model. Moreover, 1,25(OH)2D3 failed to protect against apoptosis induced by serum starvation or incubation with the protein kinase inhibitor, staurosporine. These in vitro findings are thus at variance with several previous reports in the literature and suggest that induction of or protection against apoptosis of bone-derived cells may not be a primary function of vitamin D3.

Hybridization of alpha class subunits generating a functional glutathione transferase A1-4 heterodimer.

Within the Alpha class of the mammalian glutathione transferases two variants of subunit interfaces exist. One is conserved among the A4 subunits, whereas the second one is found in all other members of the Alpha class. The ability of the two Alpha class subunit interfaces to adopt a functional heterodimeric structure has been investigated here.The heterodimer GST A1-4 was obtained by co-expression of the two human Alpha class subunits A1 and A4 in Escherichia coli. A histidine tail was added to the N terminus of the A1 subunit to facilitate the purification of the heterodimer. The heterodimer was formed in a small proportion implying that the efficiency of the hybridization between subunit A1 and A4 is less than the propensity for homodimer formation. The hybrid enzyme was stable at low temperatures, but the two subunits dissociated and reassociated into homodimers at 40 degrees C. Three different substrates were used for subunit-selective kinetic characterization of the GST A1-4 heterodimer: 1-chloro-2,4-dinitrobenzene, nonenal and Delta(5)-androstene-3,17-dione. Both subunit A1 and subunit A4 were active in GST A1-4, but the specific activities and k(cat) values were lower than the average values of the two parental isoenzymes. However, at high temperatures the subunits of the hybrid enzyme dissociated and formed homodimers, and the activities increased to expected values. Hence, the low activities of the individual subunits in the heterodimer were reversible. The non-additive kinetic properties of the subunits in the heterodimer therefore highlight the importance of fine-tuned subunit interactions for optimal catalytic efficiency of GST A1-1 and GST A4-4.