Ultrastructural localization of human HL-A membrane antigens by use of hybrid antibodies

The localization of HL-A histocompatibility antigens at the surface of human lymphocytes in electron microscopy has been studied using hybrid antibodies to bind electron-dense particles (ferritin and plant viruses) to anti-HL-A antibody. A discontinuous distribution of the markers is observed at the cell surface, which is identical with that described for H-2 antigens on mouse lymphocytes with the same technique. Double labelling experiments suggest that the areas of the cell surface where HL-A antigens are detected contain also the heterologous lymphocyte antigens detected by an anti-thymocyte serum and that HL-A antigens are not renewed at a detectable level during the period of the labelling procedure in the areas of the cell surface which are not labelled primarily with ferritin-anti-IgG-anti-HL-A complexes. The interpretation of the discontinuous labelling of HL-A antigens with direct immunoferritin techniques is discussed.     

Identification of BRaf-Sparing Amino-Thienopyrimidines with Potent IRE1α Inhibitory Activity

Amino-quinazoline BRaf kinase inhibitor 2 was identified from a library screen as a modest inhibitor of the unfolded protein response (UPR) regulating potential anticancer target IRE1α. A combination of crystallographic and conformational considerations were used to guide structure-based attenuation of BRaf activity and optimization of IRE1α potency. Quinazoline 6-position modifications were found to provide up to 100-fold improvement in IRE1α cellular potency but were ineffective at reducing BRaf activity. A salt bridge contact with Glu651 in IRE1α was then targeted to build in selectivity over BRaf which instead possesses a histidine in this position (His539). Torsional angle analysis revealed that the quinazoline hinge binder core was ill-suited to accommodate the required conformation to effectively reach Glu651, prompting a change to the thienopyrimidine hinge binder. Resulting analogues such as 25 demonstrated good IRE1α cellular potency and imparted more than 1000-fold decrease in BRaf activity.     

Radiation dose, chemotherapy and risk of soft tissue sarcoma after solid tumours during childhood

Soft tissue sarcoma (STS) is one of the most frequent second primary cancer that occurs during the first 20 years following treatment for a solid cancer in childhood. Our aim was to quantify the risk of STS as a second malignant neoplasm and to investigate its relationship with radiotherapy and chemotherapy. A cohort study of 4,400 3-year survivors of a first solid cancer diagnosed during childhood in France or the United Kingdom, between 1942 and 1985, was followed 15 years on average. In a partially nested case-control study, we matched 25 cases of STS and 121 controls for sex, type of first cancer, age at first cancer and duration of follow-up. Sixteen STS occurred in the cohort, as compared to 0.3 expected from the general population (Standardized Incidence Radio, SIR = 54 (95%CI: 34-89)). The SIR was 113 (95% CI: 62-185) after chemotherapy plus radiotherapy (13 STS), whereas it was 28 (95%CI: 2-125) after chemotherapy alone (1 STS) and 19 (95%CI: 3-60) after radiotherapy alone (2 STS). After adjustment for treatment, there was no evidence of variation in the annual excess of incidence or in the SIR with either age at first cancer or time since 1st cancer. In the case-control study, the risk of a STS was increased with the square of the dose of radiation to the site of STS development and with the administration of Procarbazine. The increased risk of soft tissue sarcoma that occurred after childhood cancer is independently related to exposure to radiotherapy and Procarbazine. A closer surveillance of children treated with this treatment combination is strongly recommended.     

Favorable outcome in a case of Mycoplasma pneumoniae-associated crescentic glomerulonephritis

Mycoplasma pneumoniae-associated nephritis has been reported in children with various pathological findings. It nevertheless remains an uncommon disease and, within this clinical context, endo-and extracapillary glomerulonephritis in a child has never been described. We report here a case of a 3-year-old girl diagnosed with severe crescentic glomerulonephritis associated with M. pneumoniae infection who presented with nephrotic syndrome and impaired renal function. The serum C3 complement level was initially low but returned to normal after 1 month. Two courses of three methylprednisolone pulses were administered in association with plasmapheresis and, secondarily, mycophenolate mophetil. This treatment regimen led to disease remission and a favorable renal outcome at the 6-month follow-up. However, the treatment guidelines in this situation remain debatable.     

Atypical thyrotropin-secreting pituitary microadenoma revealed by severe osteoporosis in a young man

For 10 years, a young man was followed for a severe osteoporosis associated with a considerable reduction in height and a massive weight loss. The constant increase of signs of tissue impregnation with thyroid hormones and the molar ratios of α-TSH suggested an inappropriate secretion of thyrotropin. Magnetic resonance imaging finally revealed a thyrotropic microadenoma of the pituitary gland. This case gives some new additional information on thyrotropin-induced osteoporosis. To our knowledge such a case has never been reported in the literature.     

Neuronal in vitro models for the estimation of acute systemic toxicity

The objective of the EU funded integrated project “ACuteTox” is to develop a strategy in which general cytotoxicity, together with organ-specific endpoints and biokinetic features, are taken into consideration in the in vitro prediction of oral acute systemic toxicity. With regard to the nervous system, the effects of 23 reference chemicals were tested with approximately 50 endpoints, using a neuronal cell line, primary neuronal cell cultures, brain slices and aggregated brain cell cultures. Comparison of the in vitro neurotoxicity data with general cytotoxicity data generated in a non-neuronal cell line and with in vivo data such as acute human lethal blood concentration, revealed that GABA_A receptor function, acetylcholine esterase activity, cell membrane potential, glucose uptake, total RNA expression and altered gene expression of NF-H, GFAP, MBP, HSP32 and caspase-3 were the best endpoints to use for further testing with 36 additional chemicals. The results of the second analysis showed that no single neuronal endpoint could give a perfect improvement in the in vitro–in vivo correlation, indicating that several specific endpoints need to be analysed and combined with biokinetic data to obtain the best correlation with in vivo acute toxicity.     

A Single Intravenous sTNFR-Fc Administration at the Time of Reperfusion Limits Infarct Size—Implications in Reperfusion Strategies in Man

Background  Reperfusion of the ischemic myocardium is associated with increased inflammatory processes that can exert deleterious effects and therefore contribute to cardiac dysfunction. The aim of the present study was to verify whether the administration of sTNFR-Fc, a scavenger of the pro-inflammatory cytokine TNF-α, at the time of reperfusion would protect against myocardial infarction and reduce the severity of early mechanical dysfunction. Methods  Male Wistar rats were subjected to 60 min coronary occlusion followed by reperfusion. A bolus of sTNFR-Fc (10 μg/kg, i.v.) (MI + sTNFR-Fc group) or a placebo (MI group) was injected prior to reperfusion. Cardiac geometry was assessed by echocardiography 1, 3 and 7 days after reperfusion. Eight days after reperfusion, left ventricular (LV) function was evaluated under basal conditions and during an experimental challenge of volume overload. Finally, infarct size was measured after euthanasia. Results  sTNFR-Fc administration markedly reduced infarct size (P < 0.01) and decreased LV dilation as assessed by the echocardiographic measurement of the LV end diastolic area, 7 days post-MI (P < 0.01). Moreover, LV end-diastolic pressure was significantly preserved by sTNFR-Fc 1 week after myocardial infarction, under basal conditions (P < 0.05) as well as during cardiac overload (P < 0.05). Conclusion  A single administration of sTNFR-Fc at the time of reperfusion after myocardial infarction is able to limit infarct size and to reduce early LV diastolic dysfunction in rats. These findings suggest that intravenous neutralization of TNF-α during surgical cardiac reperfusion might improve the outcome of myocardial infarction in humans.