A physiological threshold for protection against menadione toxicity by human NAD(P)H:quinone oxidoreductase (NQO1) in Chinese hamster ovary (CHO) cells

NAD(P)H:quinone oxidoreductase 1 (NQO1) has often been suggested to be involved in cancer prevention by means of detoxification of electrophilic quinones. In the present study, a series of Chinese hamster ovary (CHO) cell lines expressing various elevated levels of human NQO1 were generated by stable transfection. The level of NQO1 over-expression ranged from 14 to 29 times the NQO1 activity in the wild-type CHO cells. This panel of cell lines, allowed investigation of the protective role of NQO1 in quinone cytotoxicity. It could be demonstrated that menadione toxicity was significantly reduced in all NQO1-transfected CHO clones compared to the wild-type cells, but the clones did not show differences in their level of protection against menadione. This observation pointed at a critical threshold concentration of NQO1 above which a further increase does not provide further protection against quinone cytotoxicity. Additional studies in which the NQO1 activity was inhibited by dicoumarol showed that only dicoumarol concentrations of about five times the EC(50) for NQO1 inhibition were able to reduce NQO1 levels below the apparent threshold, making the cells more sensitive. The level of this threshold was estimated to be in the range of base line NQO1 activities observed in several tissues and species. Thus, the results of the present study indicate that beneficial effects of NQO1 induction by, for example, cruciferous vegetables might be absent or present depending on the NQO1 activity threshold for optimal protection and the basal level of NQO1 expression in the tissue and species of interest.     

Coexpression of endothelial markers and CD14 by cytokine mobilized CD34+ cells under angiogenic stimulation

OBJECTIVE: A subset of adult peripheral blood leukocytes functions as endothelial progenitor cells that incorporate into the vasculature in animal models of neovascularization. The basic mechanisms by which differentiation proceeds are still unclear. This study analyses the in vitro differentiation of cytokine mobilized, human CD34(+) cells. METHODS: Granulocyte-monocyte colony stimulating factor mobilized human CD34(+) cells were isolated and grown in culture in the presence of vascular endothelial growth factor (50 ng/ml) and basic fibroblast growth factor (10 ng/ml). Their differentiation was followed using cytological and immunohistochemical techniques. Fibronectin-coated culture dishes or three-dimensional cultures were used. RESULTS: CD34(+) cells grown on fibronectin-coated dishes differentiated along the granulocytic and monocytic/macrophage lineages with no evidence for an endothelial cell differentiation. CD14(+) macrophages appeared in long-term culture and then acquired endothelial cell markers such as VE-cadherin, the endothelial form of NO synthase and the von Willebrand factor. Yet they were unable to form tubular structures in Matrigel. Only typical macrophages were observed in Matrigel. CONCLUSION: Angiogenic stimulation of CD34(+) precursor cells leads to cells that expressed mixed macrophage and endothelial cell properties. They could represent an intermediate phenotype in the pathway that leads to mature endothelial cells.     

Mesalamine-related lung disease: clinical, radiographic, and pathologic manifestations

Lung injury related to mesalamine (5-aminosalicylic acid) has rarely been reported in patients with inflammatory bowel diseases. Patients present with progressive respiratory symptoms and radiographic abnormalities whose genesis may occur from days to years after initiation of therapy. Although pathologic features overlap with other pulmonary disorders, findings of chronic interstitial pneumonia and poorly formed nonnecrotizing granulomas should prompt consideration of mesalamine-related lung disease in a patient receiving this medication. The authors describe the clinical, radiographic, and pathologic manifestations of mesalamine-related lung disease in three patients and review the literature related to this topic.     

Surgical view of the treatment of patients with hepatoblastoma: results from the first prospective trial of the International Society of Pediatric Oncology Liver Tumor Study Group

BACKGROUND: Surgical resection is the cornerstone of treatment for patients with hepatoblastoma (HB). The Society of Pediatric Oncology Liver Tumor Study Group launched its first prospective trial (SIOPEL-1) with the intention to treat all patients with preoperative chemotherapy and delayed surgical resection. The objective of this article was to assess the assumed surgical advantages of primary chemotherapy. METHODS: Between 1990 and 1994, 154 patients age < 16 years with HB were registered on SIOPEL-1. The pretreatment extent of disease was assessed, and, after undergoing biopsy, patients were treated with cisplatin 80 mg/m(2) intravenously over 24 hours and doxorubicin 60 mg/m(2) intravenously over 48 hours by continuous infusion (PLADO). Generally, tumors were resected after four of a total of six courses of PLADO. RESULTS: One hundred twenty eight patients underwent surgical resection (13 patients underwent primary surgery, and 115 patients underwent delayed surgery after PLADO). A pretreatment surgical biopsy was performed in 96 of 128 patients (75%). Biopsy complications occurred in 7 of 96 patients (7%). Twenty-two patients showed pulmonary metastases at the time of diagnosis, and 7 patients underwent thoracotomy. Operative morbidity and mortality were 18% and 5%, respectively. Complete macroscopic surgical resection was achieved in 106 patients (92%), including 6 patients who underwent orthotopic liver transplantation. The actuarial 5-year event free survival (EFS) rate for all 154 patients in the study was 66%, and the overall survival (OS) rate was 75%. For the 115 patients who were included in the surgical analysis that followed the exact protocol, the EFS and OS rates were 75% and 85%, respectively. CONCLUSIONS: Biopsy is a safe procedure and should be performed routinely. Preoperative chemotherapy seems to make tumor resection easier. Reresection of a positive resection margin does not necessarily have to be performed, because postoperative chemotherapy showed good results. Resection of lung metastases can be curative if there is local control of the primary tumor; however, results showed that the patient's prognosis was worse. Surgical morbidity or mortality rates were not necessarily higher in large multicenter studies. More importantly, countries of lesser economic status also can contribute effectively to these trials.     

Volatiles from the venom of five species of paper wasps (Polistes dominulus, P. gallicus, P. nimphus, P. sulcifer and P. olivaceus).

The venom volatiles of five paper wasp species, four European belonging to the subgenus Polistes sensu stricto (P. dominulus, P. gallicus, P. nimphus, P. sulcifer) and one belonging to the Asian subgenus Gyrostoma (P. olivaceus), have been sampled by headspace solid phase micro-extraction and analysed by gas chromatography-mass spectrometry. The venom volatile components of Polistes wasps have never been fully investigated before, although the presence of some spiroacetals has been previously reported in literature. The composition of the venom was qualitatively and quantitatively different among the analysed species with the major substances tentatively identified, on the basis of their mass spectra, as: spiroacetals, mainly 2,8-dimethyl-1,7-dioxaspiro[5.5]undecane, two amides, N-(3-methylbutyl)acetamide and N-(3-methylbutyl)propanamide and acetates of saturated, mono- and di-unsaturated 2-alcohols with an odd number of carbon atoms in the chain. The acetate of a di-unsaturated 2-alcohol, present in two isomeric forms, identified as (E)- and (Z)-5-tangerinol has never been reported in literature for insects. Propanoates of the same 2-alcohols were only found in the venom of P. gallicus. Both the amides and the above-mentioned spiroacetal have been already shown to be alarm pheromones in other social wasps, while the acetates and propanoates have ever been reported in this taxon.     

Properties underlying the influence of nicotinic receptors on neuronal excitability and epilepsy

The great diversity of neuronal nAChRs equips them for many roles. The broad, diffuse projections of the cholinergic system and their influence on multiple neurotransmitter systems enable nAChRs to have a wide modulatory influence on excitability on multiple time scales. Both excitatory and inhibitory synapses are directly modulated by nAChR activity. Although fast nicotinic transmission is not a major excitatory drive, it may alter the excitability of many synapses at one time. Depending on the neural area and stage of development, nAChRs of multiple subtypes will have varying degrees of importance in regulating neuronal excitability.     

Phosphatidylinositol 3'-kinase/AKT signaling is activated in medulloblastoma cell proliferation and is associated with reduced expression of PTEN.

PURPOSE: Medulloblastomas represent the most frequent malignant brain tumors of childhood. They are supposed to originate from cerebellar neural precursor cells. Recently, it has been shown that Sonic Hedgehog-induced formation of medulloblastoma in an animal model is significantly enhanced by activation of the phosphatidylinositol 3'-kinase (PI3K) signaling pathway. EXPERIMENTAL DESIGN: To examine a role for PI3K/AKT signaling in the molecular pathogenesis of human medulloblastoma, we did an immunohistochemical study of the expression of Ser473-phosphorylated (p)-AKT protein in 22 medulloblastoma samples: All samples displayed p-AKT expression. To investigate if an activated PI3K/AKT pathway is required for medulloblastoma cell growth, we treated five human medulloblastoma cell lines with increasing concentrations of the PI3K inhibitor LY294002 and analyzed cellular proliferation and apoptosis. The antiproliferative effect could be antagonized by overexpressing constitutively active AKT. As the activation of PI3K/AKT signaling may be associated with alterations of the PTEN gene located at 10q23.3, a chromosomal region subject to frequent allelic losses in medulloblastoma, we screened PTEN for mutations and mRNA expression. RESULTS: Proliferation of all of the medulloblastoma cell lines was dependent on PI3K/AKT signaling, whereas apoptosis was not prominently affected. Allelic loss was detected in 16% of the cases. One medulloblastoma cell line was found to carry a truncating mutation in the PTEN coding sequence. Even more important, PTEN mRNA and protein levels were found to be significantly lower in medulloblastomas compared with normal cerebellar tissue of different developmental stages. Reduction of PTEN expression was found to be associated with PTEN promoter hypermethylation in 50% of the tumor samples. CONCLUSIONS: We conclude that activation of the PI3K/AKT pathway constitutes an important step in the molecular pathogenesis of medulloblastoma and that dysregulation of PTEN may play a significant role in this context.     

RNASEL mutation screening and association study in Ashkenazi and non-Ashkenazi prostate cancer patients.

Epidemiologic and genetic studies support the considerable effect of heritable factors on prostate tumorigenesis, although to date, no unequivocal susceptibility gene has been identified. The extensive study of RNASEL in prostate cancer patients worldwide has yielded conflicting results. We reevaluated the role of the RNASEL 471delAAAG Ashkenazi founder mutation in 1,642 Ashkenazi patients with prostate, bladder, breast/ovarian, and colon cancers; Ashkenazi controls; and in non-Ashkenazi prostate cancer patients and controls. The entire RNASEL coding sequence was also screened using denaturing high-performance liquid chromatography and multiplex ligation-dependent probe amplification for possible sequence variations or copy number changes in a population of prostate cancer patients. The 471delAAAG mutation was detected in 2.4% of the Ashkenazi prostate cancer patients; in 1.9% of patients with bladder, breast/ovarian, and colon cancers; and in 2.0% of the Ashkenazi controls. Seven additional variants were detected in RNASEL, including a novel potentially pathogenic splice site mutation, IVS5+1delG, although none were associated with increased prostate cancer risk. Multiplex ligation-dependent probe amplification analysis showed two RNASEL gene copies in all 300 prostate cancer patients tested. We estimated that the RNASEL 471delAAAG founder mutation, which was detected in 2% of the Ashkenazi Jews, originated between the 2nd and 5th centuries A.D., compared with the less frequent (1%) BRCA1 185delAG founder mutation, which originated hundreds of years earlier. Taken together, our analysis does not support a role for the RNASEL 471delAAAG Ashkenazi mutation nor for the other alterations detected in RNASEL in prostate cancer risk in Jewish men.     

Effect of the Concurrent LHRH Antagonist Administration with a LHRH Superagonist in Rats

Purpose. The purpose of this study was to investigate the effect of anovel LHRH antagonist, Orntide acetate, on the initial testosteroneelevation in rats during treatment with a LHRH superagonist,Leuprolide acetate.Methods. Thirteen groups of a rat animal model were administeredeither liquid Orntide or Orntide PLGA microspheres before or simultaneouslywith Leuprolide injections. Serum levels of testosterone weremonitored during the time course of the study using a radioimmunoas say method.Results. Administration of a single daily dose of liquid Orntide resultedin testosterone suppression within 6 h to levels below 0.5 ng/ml(castration level). However, combined administration of liquid Orntide andliquid Leuprolide did not have a significant effect on the initialtestosterone elevation in studied rats. Similarly, there was no effect when liquidOrntide was co-administered with Leuprolide microspheres. Administrationof Orntide microspheres 48 h before Leuprolide microspheressuppressed testosterone levels below the castration level within 24 h,however, did not prevent a rise in testosterone serum concentration uponadministration of Leuprolide microspheres. Also, a second testosteronepeak was observed between days 3 and 15 in the animals which weresimultaneously treated with Orntide microspheres and Leuprolidemicrospheres.Conclusions. Orntide acetate was found to be an effective LHRHantagonist with a rapid onset of pharmacological action and a shortbiological half-life. Administration of a single dose of liquid Orntideor Orntide microspheres, resulted in rapid testosterone suppressionwithout an initial elevation, as seen with LHRH superagonists. However,combined administration of Orntide and Leuprolide did not havean effect on the initial testosterone elevation in rats.