The use of caspase inhibitors in pulsed-field gel electrophoresis may improve the estimation of radiation-induced DNA repair and apoptosis

<p>Abstract</p> <p>Background</p> <p>Radiation-induced DNA double-strand break (DSB) repair can be tested by using pulsed-field gel electrophoresis (PFGE) in agarose-encapsulated cells. However, previous studies have reported that this assay is impaired by the spontaneous DNA breakage in this medium. We investigated the mechanisms of this fragmentation with the principal aim of eliminating it in order to improve the estimation of radiation-induced DNA repair.</p> <p>Methods</p> <p>Samples from cancer cell cultures or xenografted tumours were encapsulated in agarose plugs. The cell plugs were then irradiated, incubated to allow them to repair, and evaluated by PFGE, caspase-3, and histone H2AX activation (γH2AX). In addition, apoptosis inhibition was evaluated through chemical caspase inhibitors.</p> <p>Results</p> <p>We confirmed that spontaneous DNA fragmentation was associated with the process of encapsulation, regardless of whether cells were irradiated or not. This DNA fragmentation was also correlated to apoptosis activation in a fraction of the cells encapsulated in agarose, while non-apoptotic cell fraction could rejoin DNA fragments as was measured by γH2AX decrease and PFGE data. We were able to eliminate interference of apoptosis by applying specific caspase inhibitors, and improve the estimation of DNA repair, and apoptosis itself.</p> <p>Conclusions</p> <p>The estimation of radiation-induced DNA repair by PFGE may be improved by the use of apoptosis inhibitors. The ability to simultaneously determine DNA repair and apoptosis, which are involved in cell fate, provides new insights for using the PFGE methodology as functional assay.</p

Antenatal treatment in two Dutch families with pyridoxine-dependent seizures

Contains fulltext : 88199.pdf (publisher's version ) (Closed access)Incidental reports suggest that antenatal treatment of pyridoxine dependent seizures (PDS) may improve neurodevelopmental outcome of affected patients. Two families with PDS are reported, both with two affected siblings. Antenatal treatment with pyridoxine was instituted during the second pregnancy in each family (50 and 60 mg daily from 3 and 10 weeks of gestation, respectively). Perinatal characteristics and neurodevelopmental outcome at 4 (Family A) and 12 (Family B) years of age were compared between the untreated and treated child within each family. Meconium-stained amniotic fluid was present in both first pregnancies and abnormal foetal movements were noticed in one. In the treated infants, pregnancy and birth were uncomplicated. In family A, postnatal pyridoxine supplementation prevented neonatal seizures. Both children in family A were hypotonic and started walking after 2 years of age; both had white matter changes on MRI, and the first child was treated for squint. IQ was 73 and 98 in the antenatally untreated and treated child, respectively. The second child in family B developed seizures on the seventh day, because pyridoxine maintenance therapy had not been instituted after birth. Seizures responded rapidly to pyridoxine supplementation. MRI showed large ventricles and a mega cisterna magna. IQ was 80 and 106 in the antenatally untreated and treated child respectively. Both children had normal motor development. These results suggest that antenatal pyridoxine supplementation may be effective in preventing intrauterine seizures, decreasing the risk of complicated birth and improving neurodevelopmental outcome in PDS.1 maart 201

Gadolinium-DTPA enhanced MRI in neonatal osteomyelitis of the cervical-spine

Although the radiographic features of neonatal osteomyelitis are well described, spinal localizations are very rare and occur in about 2–4%. Clinical presentation with paresis and paralysis occurs in less than 1% (Resnick & Niwayama, 1988). In the neonate negative bone scintigraphy in the presence of bony destruction is not inconsistent with osteomyelitis as in the presented case (Swischuk, 1989). Magnetic resonance imaging (MRI) reports of these cases are scarce (Lac et al, 1990) and Gadolinium-DTPA enhanced MRI has not yet been described. Our recent experience with this unusual but characteristic presentation prompted this report

Postprandial chylomicron clearance rate in late teenagers with diabetes mellitus type 1

A delayed chylomicron (CM) clearance rate, a known risk factor for atherosclerosis, has been described in adults with diabetes type I (DMI). We determined the CM clearance rate in late teenagers with DM1, and the relationship between CM clearance rate and elevated plasma lipid concentrations in DMI teenagers in poor metabolic control (as characterized by HbA(1c) percentage). Plasma lipids and CM clearance were determined in nine patients with DMI (mean age +/- SD: 17.5 +/- 0.6 y) and four healthy controls (mean age +/- SD: 20.1 +/- 0.8 y), by measuring breath (CO2)-C-13, plasma triglyceride, retinyl palmitate, and C-13-labeled oleic acid concentrations, after oral administration of a fat-rich meal together with vitamin A and C-13-oleic acid. In patients with DMI, fasting triglyceride and cholesterol concentrations were positively correlated with HbA(1c) percentage (p <0.05). Neither in DM1 patients, nor in controls, was an elevated triglyceride concentration (above 1.7 mmol/L) found. Yet, in 22% of DMI patients, cholesterol concentration was above 5.2 mmol/L, but not in any of the controls. CM clearance rate in DMI patients was similar to that in controls and did not significantly correlate with HbA(1c) percentage. Fasting lipid concentrations in DMI patients were not significantly correlated with CM clearance rate. Present data indicate that elevated lipid concentrations in late teenagers with DMI are not attributable to a delay in CM clearance rate. A delayed CM clearance rate at late teenager age is not a risk factor contributing to the increased risk for atherosclerosis in DM1