Maria Gentile

NMR Studies on Structure and Dynamics of the Monomeric Derivative of BS-RNase: New Insights for 3D Domain Swapping

Three-dimensional domain swapping is a common phenomenon in pancreatic-like ribonucleases. In the aggregated state, these proteins acquire new biological functions, including selective cytotoxicity against tumour cells. RNase A is able to dislocate both N- and C-termini, but usually this process requires denaturing conditions. In contrast, bovine seminal ribonuclease (BS-RNase), which is a homo-dimeric protein sharing 80% of sequence identity with RNase A, occurs natively as a mixture of swapped and unswapped isoforms. The presence of two disulfides bridging the subunits, indeed, ensures a dimeric structure also to the unswapped molecule. In vitro, the two BS-RNase isoforms interconvert under physiological conditions. Since the tendency to swap is often related to the instability of the monomeric proteins, in these paper we have analysed in detail the stability in solution of the monomeric derivative of BS-RNase (mBS) by a combination of NMR studies and Molecular Dynamics Simulations. The refinement of NMR structure and relaxation data indicate a close similarity with RNase A, without any evidence of aggregation or partial opening. The high compactness of mBS structure is confirmed also by H/D exchange, urea denaturation, and TEMPOL mapping of the protein surface. The present extensive structural and dynamic investigation of (monomeric) mBS did not show any experimental evidence that could explain the known differences in swapping between BS-RNase and RNase A. Hence, we conclude that the swapping in BS-RNase must be influenced by the distinct features of the dimers, suggesting a prominent role for the interchain disulfide bridges.

Infection with Mycobacterium tuberculosis complicating a pulmonary sequestration

Pulmonary sequestration is a relatively rare malformation. Infection with common pyogenes is a frequent feature in the evolution of this disease. We report a case of intralobar sequestration infected with Mycobacterium tuberculosis in the absence of any other site of tuberculous infection. The patient underwent surgical removal of the affected lobe and subsequent antituberculous chemotherapy. At 1-year follow-up his clinical status is excellent.

Secretory Phospholipase A2: A Putative Mediator of Airway Inflammation

Accessible online at: http://BioMedNet.com/karger Correspondence to: Dr. Massimo Triggiani Division of Clinical Immunology and Allergy University of Naples Federico II Via Pansini 5, I–80131 Naples (Italy) Tel. +39 81 7462219, Fax +39 81 7462271, E-Mail triggian@unina.it Phospholipases are enzymes responsible for the remodeling of cellular phospholipids and for the generation of intracellular messengers and of arachidonic acid, the percursor of eicosanoids [1]. Different groups of phospholipases A2 (PLA2) have been identified in mammalian cells according to their molecular weight, subcellular location and calcium requirements [1]. Increasing attention has been given to the group 2 secretory PLA 2 (sPLA2), since this enzyme appears to be associated with inflammatory reactions [2]. sPLA2 was initially identified in the synovial fluid of patients with rheumatoid arthritis [3]. Elevated levels of sPLA2 were also found in nasal lavage of patients with allergic rhinitis [4], in the bronchoalveolar lavage of patients with asthma after allergen challenge [5, 6] and in pleural fluid of patients with lung cancer [Triggiani et al. unpubl. data]. It has been shown that sPLA 2 is activated in the extracellular environment and it induces mediator release and cytokine synthesis in inflammatory cells such as mast cells, macrophages, fibroblasts and platelets [7, 8]. Bronchial instillation of sPLA2 induces bronchoconstriction, extensive neutrophil infiltration and tissue damage [2]. Many of the effects of sPLA2 are mediated by the activation of a specific membrane receptor [7]. The aim of this study was to determine the cellular sources of sPLA 2 in human airways and to characterize initially the effect of this enzyme on human lung macrophages. International Archives of Allergy and Immunology

Phase I–II study of gemcitabine and paclitaxel in pretreated patients with stage IIIB–IV non-small cell lung cancer

Gemcitabine and paclitaxel are among the most active new agents in non-small cell lung cancer (NSCLC) and are worth considering for second-line chemotherapy. In this phase I-II study, we combined gemcitabine and paclitaxel for second-line treatment of advanced NSCLC. Gemcitabine doses were kept fixed at 1000 mg/m2 on day 1 and 8, and paclitaxel doses were escalated from 90 mg/m2 on day 1 of the 21-day cycle. Thirty-seven patients were treated at six different dose levels. Grade 4 neutropenia was dose-limiting toxicity (DLT), since it occurred in two out of six patients treated at paclitaxel 240 mg/m2; the paclitaxel dose level just below (210 mg/m2) was selected for phase Il evaluation. Non-hematologic toxicity was mild. One complete response (CR) (3%) and 13 partial responses (PR) (36%) were observed in 36 evaluable patients for an overall response rate of 39% (95% C.I., 23-57%). Median duration of response was 35 weeks (range, 8-102). All of the observed objective responses occurred in the 19 patients who had previously responded to the first-line therapy. Median survival was 40 weeks (range, 8-108 weeks). The combination of gemcitabine and paclitaxel is a feasible, well-tolerated, and active scheme for second-line treatment of advanced NSCLC; further evaluation, at least in selected patients, such as those previously responding to first-line chemotherapy, is definitely warranted.

Phase I study of vinorelbine and paclitaxel in small-cell lung cancer

Background: Vinorelbine and paclitaxel interfere with mitotic spindle function through different mechanisms of action. Both of the drugs show antitumor activity in small-cell lung cancer when used as single agents; furthermore, in vitro and in vivo studies have shown a synergistic activity between the two drugs. Patients and methods: Patients with small-cell lung cancer no longer amenable to conventional treatment were entered into a phase I study in which vinorelbine was given at a fixed dose of 30 mg/m2 by 15-min intravenous infusion, whereas paclitaxel was given by 3-h infusion starting 1 h after vinorelbine at an initial dose of 90 mg/m2, which was subsequently escalated by 30-mg/m2 steps. Cycles were repeated every 21 days. Results: Grade 3 neutropenia was observed only in three patients treated at the fifty dose level. Thrombocytopenia never reached grade 3. Neurotoxicity was considered dose-limiting, since grade 3 peripheral neuropathy occurred in three of five patients treated at the fifth dose level (paclitaxel 210 mg/m2). Other side effects were generally mild. The overall response rate in 22 evaluable patients was 32% (95% CI 13–51%); in particular, 1 complete response (4.5%) and 6 partial responses (27.3%) were observed. The maximally tolerated doses recommended for phase II studies are 180 mg/m2 for paclitaxel and 30 mg/m2 for vinorelbine. The observed myelosuppression was less severe than anticipated on the basis of the effects of each drug alone. Conclusions: The promising activity of this drug combination warrants a phase II study in untreated patients with extensive-stage small-cell lung cancer.

Phase II study of mitomycin C, etoposide and vindesine in metastatic stage IV non-small-cell lung cancer

SummaryA total of 72 patients with metastatic stage IV non-small-cell lung cancer (NSCLC) were treated with combination chemotherapy comprising the MEV regimen (mitomycin C, 8 mg/m2 given i. v. on day 1; etoposide, 100 mg/m2 given i.v. on days 1–3; and vindesine, 3 mg/m2 given i.v. on day 1; treatment repeated every 3 weeks). In 64 evaluable patients, the objective response rate was 37% (complete responses, 4.7%; partial responses, 32.3%). The median survival was 7.6 months for all patients. The treatment was very well tolerated. MEV proved to be an active and non-toxic regimen for the treatment of metastatic NSCLC.

NEOADJUVANT CHEMOTHERAPY WITH CISPLATIN, EPIRUBICIN AND VP-16 FOR STAGE IIIA-IIIB NON-SMALL-CELL LUNG CANCER : A PILOT STUDY

Twenty patients with stage IIIA-IIIB non-small-cell lung cancer were treated with cisplatin, epirubicin and VP-16 (PEV) neoadjuvant chemotherapy (CDDP, 70 mg/m2, i.v., d 1; EDX, 60 mg/m2, i.v., d 1; VP-16, 100 mg/m2, i.v., d 1-2-3; every 3 weeks). A partial response was obtained In 11 cases (55%), stable disease in 3 cases (15%), and progressive disease in 6 cases (30%). After chemotherapy, 8 (40%) patients, all achieving a partial response, were elegible for surgery: 5 (25%) had a complete resection (4 IIIA and 1 IIIB) and 3 (15%) an incomplete resection. The treatment was well tolerated. These data show that PEV is an active regimen for neoadjuvant chemotherapy in NSCLC and recommend this therapeutic approach for stage IIIA patients.

Are the anti-allergic properties of H1-antihistamines of any clinical relevance?

Summary Histamine is an ubiquitous messenger molecule synthetized and released from human basophils, mast cells and neurons. Its various biological effects are mediated by three pharmacologically defined receptors termed the H1, H2 and H3-receptors. The H1-receptor was the first member of this family to be pharmacologically defined with the advent of selective antagonists, the « antihistamines , which are widely used to treat allergic disorders. Recent evidence indicates that certain antihistamines exert antiallergic effects not related to H1-antagonism. However, these effects require higher doses than those regularly used. We have demonstrated that histamine induces a concentration-dependent release of IL-6, TNF-α and β-glucuronidase from human lung macrophages. These effects are inhibited by fexofenadine, an H1-receptor antagonist, but not by cimetidine, an H2-receptor antagonist. The finding that fexofenadine inhibits the human lung macrophages-activating property of histamine raises the possibility that long-term treatment with fexofenadine might inhibit tissue damage caused by human lung macrophages activated by histamine immunologically released by basophils and mast cells.

Intensive alternating combination chemotherapy and high dose chest radiotherapy in small cell lung cancer.

Sixty-nine patients, 32 with limited and 37 with extensive small cell lung cancer (SCLC), were admitted to the present study. Patients with limited disease underwent alternating combination chemotherapy consisting of CAV (cyclophosphamide, adriamycin, vincristine) and PE (cisplatin and etoposide) regimens and concurrent high dose thoracic radiotherapy (6,000 cGy); prophylactic brain irradiation (3,000 cGy) was administered to complete responders. Patients with extensive disease received the same alternating chemotherapy but not radiotherapy. In the 25 evaluable patients with limited disease we obtained an objective response (OR) in 80% with a complete response (CR) in 54% and partial response (PR) in 24%, stable disease (SD) in 4 % and progressive disease (PD) in 16%. Median duration of response was 9.5 months for CR and 8.5 months for PR. Median survival was 14 months for all patients with 12% long-term survivors. Toxicity was acceptable. In the 32 evaluable patients with extensive disease we observed 65.6% OR with 18.7% CR and 46.8% PR, 9.3% minimal response and 25 % PD. Median duration of response was 7 months for CR and 8 months for PR. Median survival was 10 months for all patients. The treatment was well tolerated. Our study did not show a therapeutic advantage for alternating combination chemotherapy in SCLC and failed to show the use of high dose chest radiotherapy in combined modality for limited disease.