P-selectin upregulation in bleomycin induced lung injury in rats: effect of N-acetyl-L-cysteine

BACKGROUND: A number of adhesion molecules are involved in the process of neutrophil infiltration into the lung. P-selectin is one of these neutrophil-endothelial cell adhesion molecules. A study was undertaken to examine the involvement of P-selectin in the development of bleomycin induced inflammation and the ability of N-acetyl-L-cysteine to reduce the potential expression of this selectin in rats. METHODS: N-acetyl-L-cysteine (3 mmol/kg po) was administered daily for seven days prior to bleomycin administration (2.5 U/kg). The kinetics of P-selectin expression and the effect of N-acetyl-L-cysteine after bleomycin treatment were measured using radiolabelled antibodies. P-selectin localisation was evaluated by immunohistochemistry and neutrophil infiltration was assessed by myeloperoxidase activity. RESULTS: Bleomycin administration resulted in an upregulation of P-selectin at 1 hour, returning to baseline at 3 hours. Myeloperoxidase activity showed a significant increase at 6 hours after bleomycin administration that lasted for 3 days. N-acetyl-L-cysteine treatment completely prevented these increases. CONCLUSION: Upregulation of P-selectin in the lung is associated with neutrophil recruitment in response to bleomycin. The beneficial effect of N-acetyl-L-cysteine on bleomycin induced lung injury may be explained in part by the prevention of neutrophil recruitment in the inflammatory stage of the disease.     

Clinical features,diagnosis, and prognosis of renal carcinoma

Significant conceptual changes have taken place in renal tumoral diseases over the last few years. As a result of the authors' broad institutional experience, this overall revision describes the most up-to-date clinical and diagnostic aspects of this condition. Emphasis is made on molecular staging and two variables that guide the prognosis of the disease, a decisive feature to establish treatment and to contribute to change current survival rates.     

Use of 201Tl SPECT Imaging to Assess the Response to Therapy in Patients with High Grade Gliomas

Purpose. To assess the potential role of ²⁰¹Tl single photon emission tomography (201-Thallium SPECT) when compared to other imaging modalities in the evaluation of the response to therapy in high grade gliomas. Materials and methods. Twenty patients with histologically proved high grade glioma have been included: 15 with glioblastoma (GBM), 3 with anaplastic astrocytoma (AA) and 2 with anaplastic oligoastrocytoma (AOA). Patients were assessed by ²⁰¹Tl SPECT, computed tomography (CT) and magnetic resonance imaging (MRI) at (a) either at the moment of maximum response to first line chemotherapy, or after the completion of radiotherapy and chemotherapy if post-surgical residual disease was present, and (b) after the completion of second line chemotherapy if disease persisted, or either a relapse or disease progression was confirmed. Final response was evaluated according to the McDonald criteria, and by comparing SPECT, CT and MRI results. Results. According to the McDonald criteria, clinical response after first line chemotherapy was 5 partial response, 7 stable disease and 8 progressive disease. Evaluation by ²⁰¹Tl SPECT was in agreement with such criteria in nearly all patients (90%). MRI findings closely agreed with the clinical follow-up. CT findings clearly differed from those observed by SPECT and MRI. After second line therapy, 10 patients progressed, 3 had stable disease and 7 had partial response. ²⁰¹Tl SPECT agreed with the clinical status in 89% cases, whereas MRI and, specially CT, fared significantly lower. Conclusion. Compared to conventional neuroimaging, ²⁰¹Tl SPECT added valuable information in the assessment of the response to therapy in our patient population; whenever findings were not conclusive and in the case of disagreement between CT and MRI findings.     

PSA-NCAM expression in the piriform cortex of the adult rat. Modulation by NMDA receptor antagonist administration

Uptake of biocytin and biotin was investigated in cultured transformed variants of neuronal (NB2a neuroblastoma) and glial (C6 astrocytoma) CNS cells. NB2a cells took up both compounds but biocytin was transported more efficiently than biotin in the nanomolar concentration range. In NB2a cells a single transport mechanism was found for biocytin with different kinetic parameters in the presence of high extracellular Na+ (Km 0.4 microM, Vmax 20 pmol/min/mg), K+ (Km 1.7 microM, Vmax 32 pmol/min/mg), or choline+ (Km 0.1 microM, Vmax 5 pmol/min/mg). Two transport systems (Km1 17 microM, Vmax1 53 pmol/min/mg; Km2 314 microM, Vmax2 360 pmol/min/mg) were identified for biotin with only system 1 being Na+-dependent. Biocytin uptake was competitively inhibited by excess biotin but not vice versa. Inhibition studies with structural analogs indicated different specificities for biotin and biocytin uptake. Biocytin uptake into C6 cells was hardly detectable whereas biotin was taken up by diffusion (kD 0.6 microl/min/mg) and a single saturable mechanism (Km 70 microM, Vmax 119 pmol/min/mg) at high extracellular Na+. High extracellular K+ enhanced biotin diffusion into C6 cells. Inhibition studies with structural analogs revealed a less specific biotin uptake mechanism in C6 than in NB2a cells. Biocytin normalized deficient biotin-dependent propionyl-CoA carboxylase activity within 4 h in biotin-deficient NB2a cells whereas in C6 cells reactivation was <20% thereby confirming that biocytin is only poorly transported into C6 cells. Specific biocytin uptake into NB2a cells is to our knowledge the first demonstration of a carrier-mediated transport mechanism for this compound. Neuronal biocytin uptake might contribute to the pathogenesis of biotinidase deficiency where biocytin is present in elevated levels.     

Epidermal growth factor receptor activation: how exon 19 and 21 mutations changed our understanding of the pathway.

The discovery of epidermal growth factor receptor (EGFR) mutations in never-smokers has been the most relevant finding ever in non-small cell lung cancer. When patients whose tumors bear the sensitizing mutations are treated with the tyrosine kinase inhibitors gefitinib or erlotinib, we witness response rates and durations never before reported, including complete responses. At the same time, the presence of EGFR mutations has raised numerous new questions, tantalizing data, and new challenges for treatment. This is particularly true as we try to generalize the findings in lung cancer to other malignancies. The indiscriminate use of gefitinib or erlotinib in the general lung cancer population results in meager survival benefit for patients. Similarly, the tyrosine kinase inhibitors have limited activity in a variety of tumor types with EGFR overexpression. This has led to the question of whether EGFR remains a viable target in patients other than those whose tumors contain mutations, and whether the modest activity of cetuximab in colorectal cancer and head and neck cancer represents all that we can expect from inhibition of this pathway in the absence of mutation. Mechanisms of pathway activation other than mutation have been discovered in recent years, and include overexpression mediated by gene amplification or by amplification of a dinucleotide repeat in the EGFR promoter, mutation of an extracellular region on EGFR generating a mutant protein termed EGFRvIII, and enhanced signaling due to heterodimerization with other members of the EGFR family, particularly overexpression of HER2/HER3. The extent to which these paths to EGFR activation will confer sensitivity to the tyrosine kinase inhibitors or to EGFR monoclonal antibodies is being explored. Thus far, published clinical data suggest that there is little room for the administration of gefitinib or erlotinib in the absence of EGFR mutations. The five articles in this edition of CCR Focus will address the various mechanisms of EGFR pathway activation and provide insight into the potential for translation into clinical relevance.     

Randomized phase III study of 3-weekly versus weekly docetaxel in pretreated advanced non-small-cell lung cancer: a Spanish Lung Cancer Group trial.

BACKGROUND: Docetaxel is a widely accepted second-line treatment in advanced non-small-cell lung cancer (NSCLC) with a risk of myelotoxicity. This study evaluated the efficacy and toxicity profile of two docetaxel regimens in NSCLC patients who had failed first-line non-docetaxel-based chemotherapy. PATIENTS AND METHODS: A total of 259 patients from 33 Spanish centers were randomized to receive either docetaxel 75 mg/m(2) administered every 3 weeks (3W arm) or docetaxel 36 mg/m(2) given weekly (1W arm) for 6 weeks followed by 2 weeks of rest. The primary end point was 1-year survival; secondary end points were median survival, time to progression, response and toxicity. RESULTS: One-year survival was 27% in the 3W and 22% in the 1W arm. Median time to progression was also similar in the two arms. Median survival was 6.6 months in the 3W arm versus 5.4 months in the 1W arm (P = 0.075). Response rates were 9.3% in the 3W arm and 4.8% in the 1W arm. More patients in the 1W arm experienced mucositis [1W, nine patients (7.2%); 3W, two patients (1.6%); P = 0.032], while febrile neutropenia was significantly higher in the 3W arm [3W, 10 patients (7.8%); 1W, one patient (0.8%); P = 0.010]. CONCLUSIONS: Both weekly and 3-weekly docetaxel were effective and well-tolerated, with different toxicity profiles. In general, there was no indication to recommend the weekly schedule. However, the significant lower rate of febrile neutropenia observed in the weekly schedule makes it a good alternative for patients at risk of severe neutropenia.