Effects of oxidants and antioxidants on chromosomal breakage in Fanconi's anemia lymphocytes.

Peripheral blood lymphocytes from eight Fanconi anemia (FA) patients, 14 FA heterozygotes, and nine normal subjects have been tested for their susceptibility to chromosomal breakage induction by diepoxybutane (DEB) and by two peroxides. In addition, the effect of five antioxidants was investigated in standard cultures and in cultures stressed either with DEB or with butylhydroperoxide (BHP) or with hydrogen peroxide (H2O2). DEB, BHP, and H2O2 dramatically increased the chromosomal breakage levels in homozygous and heterozygous FA cells. A partial correction of chromosomal instability was obtained by treating the patients' lymphocytes with antioxidants. A "protective" effect was also noted in the DEB or peroxide-stressed lymphocytes of patients and heterozygotes, grown in the presence of antioxidants

GC-MS analysis of the volatile constituents of the essential oil and aromatic waters of Artemisia annua L. at different developmental stages

Artemisia annua L. (Asteraceae) still represents the only source of artemisinin, considered as one of the most important drugs for the treatment of malaria and which, more recently, has been shown to be effective against numerous types of tumors. The foliage and inflorescence of A. annua also yield an essential oil upon hydrodistillation. This oil has been evaluated at different development stages (pre-flowering and flowering) by GC/MS. The volatile oil from plants at full blooming showed numerous constituents, with germacrene D (21.2%), camphor (17.6%), β-farnesene (10.2%), β-caryophyllene (9%), and bicyclogermacrene (4.2%) among the main ones. Aromatic waters, after extraction with n-hexane, showed the presence, among others, of camphor (27.7%), 1,8-cineole (14%), artemisia ketone (10.1%), α-terpineol (6.1%), trans-pinocarveol (5.4%), and artemisia alcohol (2%). From plants at the pre-flowering stage, aromatic waters were obtained with camphor (30.7%), 1,8-cineole (12.8%), artemisia alcohol (11.4%), artemisia ketone (9.5%), alpha-terpineol (5.8%), and trans-pinocarveol (3.0%) as the main constituents. The qualitative and quantitative profiles of the two aromatic waters were similar. These results permitted the conclusion to be made that A. annua could be harvested a long time before the onset of flowering to obtain higher yields of artemisinin or could be allowed to attain maturity to obtain valuable yields of volatile

Eye drop propranolol administration promotes the recovery of oxygen-induced retinopathy in mice

The mouse model of oxygen-induced retinopathy (OIR) is a well-established model of retinopathy of prematurity (ROP), characterized by the abnormal formation of new blood vessels, which is similar to ROP. In this model, we have recently shown that subcutaneous (sc) administration of the non-selective beta-adrenergic receptor (β-AR) blocker propranolol ameliorates angiogenic processes in the retina when its effects are evaluated at postnatal day (PD) 17. In the present study, we investigated whether propranolol application as collyrium can promote the recovery of OIR. After propranolol administration on the eye, mice were first tested for retinal concentrations of propranolol as compared with those measured after sc or per os administration. Subsequently, we determined the effects of propranolol ophthalmic solutions, at the optimal dose for delivery, on VEGF, IGF-1, hypoxia-inducible factor (HIF)-1α, signal transducer and activator of transcription 3 (STAT3) and retinal neovascularization as assessed in both the superficial and the deep vascular plexuses. The results showed that 2% topical propranolol has an efficiency (in terms of final propranolol concentration in the retina) comparable to that of 20 mg/kg propranolol sc or per os and significantly higher than those observed with doses and administration routes that are currently used with children. Propranolol ophthalmic solutions reduced VEGF and IGF-1 up-regulation in response to hypoxia and drastically inhibited HIF-1α accumulation and STAT3 phosphorylation. As a result of its inhibitory effects on hypoxia-induced proangiogenic factors, propranolol significantly reduced retinal neovascularization in the superficial but not in the deep vascular plexus. An evaluation of retinal neovascularization at PD21 showed that propranolol was still effective in inhibiting OIR. These findings strengthen the hypothesis that β-AR blockade can efficiently counteract OIR and suggest that topical eye application of propranolol can represent an alternative delivery route to systemic administration thus avoiding the risk of associated complications and side effects that could make this drug unsafe in the ROP treatment

Role of the Src homology 2 domains and interdomain regions in ZAP-70 phosphorylation and enzymatic activity.

The protein tyrosine kinase ZAP-70, which mediates T-cell antigen receptor (TCR) signalling, contains three distinct functional modules, two tandemly arranged SH2 domains, a kinase domain and a linker region (interdomain B) that connects them. ZAP-70 enzymatic activation is strictly dependent on the binding, via its SH2 domains, to the triggered TCR and on tyrosine phosphorylation. Here we utilized recombinant ZAP-70 and carried out a mutational analysis to understand the structural requirements for its activation. We show that deletion of both SH2 domains corresponding to the first 254 residues moderately increases ZAP-70 enzymatic activity on an exogenous substrate in vitro, results in increased tyrosine phosphorylation and produces subtle conformational changes, as judged by altered SDS/PAGE migration. Mutation of Tyr292, 315 and 319 to Phe in the interdomain B region, which constitute the major phosphorylation sites both in vitro and in vivo, did not affect ZAP-70 enzymatic activity. Moreover, deletion analysis of the interdomain B region established residues 320-619 as a minimal region endowed with full kinase activity. We propose that binding of ZAP-70 to the TCR promotes, through conformational changes, its extensive phosphorylation on tyrosine. However, Tyr292, 315 and 319 do not affect ZAP-70 enzymatic activity and may influence ZAP-70 signalling only indirectly by mediating its association with intracellular transducers

Mitoxantrone, etoposide, and intermediate-dose cytarabine: an effective and tolerable regimen for the treatment of refractory acute myeloid leukemia.

Thirty-two patients with refractory acute myeloid leukemia (AML) received salvage therapy with a single course of mitoxantrone 6 mg/m2 intravenous (IV) bolus, etoposide 80 mg/m2 IV for a period of 1 hour, and cytarabine (Ara-C) 1 g/m2 IV for a period of 6 hours daily for 6 days (MEC). Eighteen patients were primarily resistant to conventional daunorubicin and Ara-C induction treatment; eight patients had relapsed within 6 months from initial remission; six patients had relapsed after a bone marrow transplantation (BMT) procedure. Overall, 21 patients (66%) achieved a complete remission (CR), two (6%) died of infection during induction, and nine (28%) had resistant disease. Age greater than 50 years was the only factor predictive for a significantly lower response rate (P = .03). The median remission duration was 16 weeks; the overall median survival was 36 weeks. Severe myelosuppression was observed in all patients resulting in fever or documented infections in 91% of patients. Nonhematologic toxicity was minimal. We conclude that the MEC regimen has significant antileukemic activity and acceptable toxicity in salvage AML. Its benefit in front-line AML therapy is being investigated