LC-MS/MS Analysis on Infusion Bags and Filled Syringes of Decitabine: New Data on Physicochemical Stability of an Unstable Molecule

Many anticancer drugs are reported to have low physicochemical stability after dilution; therefore, producers impose short times from reconstitution, dilution, and the end of administration. The precariousness of cancer patients' health in real-life experience within cancer hospitals often forces delays in the drug administration with respect to the standard treatment schedule timing, because of acute toxicities or the need to postpone a control analysis before administration. The public health costs for discarded anticancer drugs due to administration interruptions can be avoided, thanks to independent analytical studies, which integrate the producer's data reported in the technical sheet, referring to the real conditions of preparation in a sterile atmosphere under a cabin in a laboratory dedicated to handling cytotoxic drugs in controlled conditions of temperature, pressure, and particulate contamination. Decitabine is apparently an unstable molecule, whose reported stability is only 3 h at 2-8 °C when diluted, while the mother solution must be immediately used or, otherwise, discarded. This study has investigated the physicochemical stability of decitabine both in diluted infusion bags and in sterile water reconstituted syringes at 4 °C for 0, 24, 48, and 72 h. In all performed studies, the stability-indicating method involves, for the first time, the use of liquid chromatography-tandem mass spectrometry analysis. Unexpectedly, both diluted and reconstituted solutions of decitabine are more stable than previously reported data, with a 48 h-long physicochemical stability at 2-8 °C and protected from light.

Combining elemental and immunochemical analyses to characterize diagenetic alteration patterns in ancient skeletal remains

Bones and teeth are biological archives, but their structure and composition are subjected to alteration overtime due to biological and chemical degradation postmortem, influenced by burial environment and conditions. Nevertheless, organic fraction preservation is mandatory for several archeometric analyses and applications. The mutual protection between biomineral and organic fractions in bones and teeth may lead to a limited diagenetic alteration, promoting a better conservation of the organic fraction. However, the correlation between elemental variations and the presence of organic materials (e.g., collagen) in the same specimen is still unclear. To fill this gap, chemiluminescent (CL) immunochemical imaging analysis has been applied for the first time for collagen localization. Then, Laser Ablation–Inductively Coupled Plasma–Mass Spectrometry (LA–ICP–MS) and CL imaging were combined to investigate the correlation between elemental (i.e., REE, U, Sr, Ba) and collagen distribution. Teeth and bones from various archeological contexts, chronological periods, and characterized by different collagen content were analyzed. Immunochemical analysis revealed a heterogeneous distribution of collagen, especially in highly degraded samples. Subsequently, LA–ICP–MS showed a correlation between the presence of uranium and rare earth elements and areas with low amount of collagen. The innovative integration between the two methods permitted to clarify the mutual relation between elemental variation and collagen preservation overtime, thus contributing to unravel the effects of diagenetic alteration in bones and teeth.

Cognitive aspects of MELAS and CARASAL

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MELAS and CARASAL have been associated with clinical evidence of cognitive impairment and should be considered as possible causes of early onset Vascular Dementia (VaD), particularly in patients with a familial history of dementia or cerebrovascular disease.

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Cognitive deterioration in MELAS involves executive function, attention, language, memory, visuospatial, and motor functioning and may correlate with the total Stroke-like episodes (SLEs) lesion load.

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CARASIL is characterized by late and slow cognition disorders, involving episodic memory, executive functions and facial recognition.

Monogenic diseases, although rare, should be always considered in the diagnostic work up of vascular dementia (VaD), particularly in patients with early onset and a familial history of dementia or cerebrovascular disease. They include, other than CADASIL, Fabry disease, Col4A1-A2 related disorders, which are well recognized causes of VaD, other heritable diseases such as mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) and cathepsin-A related arteriopathy strokes and leukoencephalopathy (CARASAL). MELAS, caused by mtDNA (80% of adult cases m.3243A>G mutations) and more rarely POLG1 mutations, has minimum prevalence of 3.5/100,000. CARASAL, which is caused by mutations in the CTSA gene, has been described in about 19 patients so far. In both these two disorders cognitive features have not been fully explored and are described only in case series or families. This review paper is aimed at providing an update on the clinical manifestations, with particular focus on cognitive aspects, but also neuroradiological and genetic features of these less frequent monogenic diseases associated with VaD.

Acute pulmonary edema in a dog with severe pulmonary valve stenosis: A rare complication after balloon valvuloplasty

Pulmonic stenosis is a frequent congenital heart disease in dogs, and the treatment of choice is balloon valvuloplasty which is usually safe and successful. The authors describe for the first time a severe complication after balloon valvuloplasty in a five-month-old dog. After effective treatment, with a considerable drop in right ventricular pressures, the dog developed hypoxemia and dyspnea due to pulmonary edema. The dog underwent intensive care and symptoms improved after a few hours of oxygen therapy, continuous positive airway pressure, and furosemide. Although this event is rare, it could have a large impact on patient survival and should be considered in the treatment of severe pulmonary valve stenosis in the future.

Near-infrared hyperspectral imaging (NIR-HSI) and normalized difference image (NDI) data processing: An advanced method to map collagen in archaeological bones

In the present study, an innovative and highly efficient near-infrared hyperspectral imaging (NIR-HSI) method is proposed to provide spectral maps able to reveal collagen distribution in large-size bones, also offering semi-quantitative estimations. A recently introduced method for the construction of chemical maps, based on Normalized Difference Images (NDI), is declined in an innovative approach, through the exploitation of the NDI values computed for each pixel of the hyperspectral image to localize collagen and to extract information on its content by a direct comparison with known reference samples. The developed approach addresses an urgent issue of the analytical chemistry applied to bioarcheology researches, which rely on well-preserved collagen in bones to obtain key information on chronology, paleoecology and taxonomy. Indeed, the high demand for large-sample datasets and the consequent application of a wide variety of destructive analytical methods led to the considerable destruction of precious bone samples. NIR-HSI pre-screening allows researchers to properly select the sampling points for subsequent specific analyses, to minimize costs and time and to preserve integrity of archaeological bones (which are available in a very limited amount), providing further opportunities to understand our past.

Novel insights into targeting ATP-binding cassette transporters for antitumor therapy

ATP-binding cassette (ABC) transporters are a large family of proteins implicated in physiological cellular functions. Selected components of the family play a well-recognized role in extruding conventional cytotoxic antitumor agents and molecularly targeted drugs from cells. Some lines of evidence also suggest links between transporters and tumor cell survival, in part unrelated to efflux. However, the study of the precise mechanisms regulating the function of drug transporters (e.g., posttranslational modifications such as glycosylation) is still in its infancy. A better definition of the molecular events clarifying the regulation of transporter levels including regulation by microRNAs may contribute to provide new molecular tools to target such a family of transporters. The present review focuses on the biological aspects that implicate ABC transporters in resistance of tumor cells, including cancer stem cells. Molecular analysis of well-known preclinical systems as well as of cancer stem cell models supports the notion that ABC transporters represent amenable targets for modulation of the efficacy of antitumor agents endowed with different molecular features. Recent achievements regarding tumor cell biology are expected to provide a rationale for developing novel inhibitors that target ABC transporters implicated in drug resistance.

Tyrosyl-DNA phosphodiesterase 1 targeting for modulation of camptothecin-based treatment

The targeting of specific DNA repair mechanisms may be a promising strategy to improve the efficacy of antitumor therapy. The cytotoxic effects of the clinically relevant topoisomerase 1 (Top1) poison camptothecins are related to the generation of DNA lesions and tumor cells may be resistant to DNA damaging agents due to increased repair. Tyrosyl- DNA phosphodiesterase 1 (TDP1) is implicated in the repair of strand breaks by removing abortive Top1/DNA complexes. Thus, a role for TDP1 in counteracting DNA damage induced by camptothecins has been proposed. Here, we review the role of TDP1 in DNA repair with particular reference to TDP1 function, its cooperation with other pathways and the development of pharmacological inhibitors.

ABC transporters as potential targets for modulation of drug resistance

ATP binding cassette transporters are implicated in multidrug resistant phenotypes of tumor cells and may be cancer stem cell markers. Inhibitors of drug efflux pumps represent an emerging group of potentially useful agents for the improvement of antitumor therapy. Here we provide an overview of drug transporter functions and modulation.

Aminolevulinic Acid in Diagnosis and Treatment of Bladder Urothelial Carcinoma

It might be difficult to diagnose either bladder's flat lesions, such as CIS, or small papillary lesions using white-light endoscopy.

Neoplastic cells can be differentiate from the normal bladder mucous membrane by using Hexyl-ALA. Hexyl aminolevulinate produces protoporphyrin's overstock inside cancer cells causing a clearly visible red fluorescence when these are hit by a predetermined wavelenght light. The purpose of this study is to evaluate effectiveness of PDD (photodynamic diagnosis) by using Hexyl-ALA to identify and treat bladder's surface cancer.

This study considers 39 patients (33 men and 6 women) from November 2008 to January 2009. On these patients were taken, previous filling of their bladders with hexyl aminolevulinate solution, 106 hystological samples (among these: 38 were first step diagnosis, 15 were a second look and 53 were taken for a relapse suspect). The 72.6% of these samples (77) were positive for cancer, while the 27,4% (29) was normal.

Of those 77 samples, 30 were discovered to be positive exclusively by using PDD and include CIS (66.6%), Ta G1–2 (20%), reactive hyperplasia (3.3%) and incipient papillary neoplasia (10%). (Anatomopathologist described the last two lesions as partial nuclear alterations not fullfilling the criteria of pathology). This research proves that, among other diagnostic methods, photodynamic diagnosis has a higher sensibility, although the specificity is lower.

Cellular Sensitivity to β-Diketonato Complexes of Ruthenium(III), Chromium(III) and Rhodium(III)

The aim of this study was to investigate cellular response to several ruthenium(III), chromium(III) and rhodium(III) compounds carrying bidentate beta-diketonato ligands: [(acac)--acetylacetonate ligand, (tfac)--trifluoroacetylacetonate ligand]. Cell sensitivity studies were performed on several cell lines (A2780, cisplatin-sensitive and -resistant U2-OS and U2-OS/Pt, HeLa, B16) using growth-inhibition assay. Effect of intracellular GSH depletion on cell sensitivity to the agents was analyzed in A2780 cells. Flow cytometry was used to assess apoptosis by Annexin-V-FITC/PI staining, and to analyze induction of caspase-3 activity. Possible DNA binding/damaging affinity was investigated, by inductively coupled mass spectrometry, and by 14C-thymidine / 3H-uridine incorporation assay. Cell sensitivity studies showed that the pattern of sensitivity to Ru(tfac)3 complex of the two cisplatin-sensitive/-resistant osteosarcoma cell lines, U2-OS and U2-OS/Pt, was similar to that of A2780 cells (72 h exposure), with the IC50 being around 40 microM. The growth-inhibitory effect of Ru(acac)3 ranged over 100 microM, while Cr(III) and Rh(III) complexes were completely devoid of antitumor action in vitro. Ru(tfac)3 exhibited strong potential for apoptosis induction on A2780 cells (up to 40%) and caused cell cycle arrest in the S phase as well as decrease of the percent of G1 and G2 cells. Ru(acac)3-induced apoptosis was slightly higher than 10%, whereas activation of caspase-3 in HeLa cells was moderate. DNA binding study revealed that only Cr(acac)3 was capable of binding DNA, while Cr(III) and Ru(III) compounds possess potential to inhibit DNA/RNA synthesis. In conclusion, only Ru(III) complexes showed potential for antitumor action.

Global gene expression of fission yeast in response to cisplatin

The cellular response to the antitumor drug cisplatin is complex, and resistance is widespread. To gain insights into the global transcriptional response and mechanisms of resistance, we used microarrays to examine the fission yeast cell response to cisplatin. In two isogenic strains with differing drug sensitivity, cisplatin activated a stress response involving glutathione-S-transferase, heat shock, and recombinational repair genes. Genes required for proteasome-mediated protein degradation were up-regulated in the sensitive strain, whereas genes for DNA damage recognition/repair and for mitotic progression were induced in the resistant strain. The response to cisplatin overlaps in part with the responses to cadmium and the DNA-damaging agent methylmethane sulfonate. The different gene groups involved in the cellular response to cisplatin help the cells to tolerate and repair DNA damage and to overcome cell cycle blocks. These findings are discussed with respect to known cisplatin response pathways in human cells.

Gene expression profiles in the cellular response to a multinuclear platinum complexe

We used cDNA arrays to monitor modulation of mRNA expression after exposure to a multinuclear platinum complex (BBR3464) in a human cervix squamous cell carcinoma cell line (A431) and in a cisplatin-resistant subline (A431/Pt) exhibiting collateral sensitivity to BBR3464. In parental A431cells, the drug induced at least twofold up-regulation of 15 genes including cell cycle and growth regulators, tumor suppressors and signal transduction genes. In cisplatin-resistant A431/Pt cells, BBR3464increased the expression of 15 genes such as apoptosis regulators and genes involved in the DNA damage response. Interestingly, BBR3464induced up-regulation of anti-metastatic factors together with down-regulation of several pro-metastatic factors. Cell cycle analysis indicated a marked G2arrest in treated A431cells, whereas an apoptotic response was documented in A431/Pt cells. These differential patterns of transcriptional profile in sensitive and resistant cells are consistent with a role for cell cycle regulation in the response to BBR3464.

Risk of soft tissue sarcomas and residence in the neighbourhood of an incinerator of industrial wastes

AIMS

To investigate the association between occurrence of soft tissue sarcomas (STS) in Mantua and residence near an incinerator of industrial wastes.

METHODS

Cases were subjects with histologically confirmed primary malignant STS diagnosed 1989-98 in the population resident in Mantua and in the three neighbouring municipalities. Controls were randomly extracted from population registries, matched for age and sex. Residential history was reconstructed for all study subjects since 1960. Main residence was geographically positioned according to GPS standards.

RESULTS

The study included 37 STS cases (17 men and 20 women) and 171 controls. The incidence of STS in the area of study was estimated as 8.8 per 100 000 in men and 5.6 per 100 000 in women. The odds ratio associated with residence within 2 km, standardised by age and sex, was 31.4 (95% CI 5.6 to 176.1), based on five exposed cases. At greater distances, risk rapidly decreased, showing a fluctuation around the null value of 1.

CONCLUSION

The study shows a significant increase in risk of STS associated with residence within 2 km of an industrial waste incinerator; an aetiological role of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) can be hypothesised.

Mechanisms controlling sensitivity to platinum complexes: role of p53 and DNA mismatch repair

Although cisplatin is effective in the treatment of different types of tumors, resistance to treatment is a major limitation. In an attempt of overcoming resistance mechanisms, a large effort has been made to generate compounds with a different geometry. At present, the most clinically relevant compounds include mononuclear (i.e. oxaliplatin) as well as multinuclear platinum complexes (i.e. BBR 3464). The mechanisms of cellular response to platinum complexes have not been completely elucidated. Among the main pathways affecting cell sensitivity of these drugs a role for p53 has been proposed at least for cisplatin and BBR 3464. Our results indicate that, also in the case of oxaliplatin, cytotoxicity is modulated by this pathway. Indeed, the effect of oxaliplatin could be reduced in tumor cells expressing mutant p53. The DNA mismatch repair system also appears to be critical in regulating cellular sensitivity to cisplatin because the loss of DNA mismatch repair results in low level of resistance to cisplatin, but not to oxaliplatin. Thus, platinum compounds are endowed with differential capability to activate pathways of p53-dependent or independent apoptosis, and differential recognition by specific cellular systems is likely to be the critical determinant of the cell fate (death/survival) after drug exposure. Further molecular studies are required to better define the precise contribution of such pathways to the cellular responses of the clinically relevant platinum complexes. A complete understanding of the molecular basis of sensitivity to platinum drugs is expected to provide useful insights for the optimization of tumor treatment.

Apoptosis and growth arrest induced by platinum compounds in U2-OS cells reflect a specific DNA damage recognition associated with a different p53-mediated response

Mononuclear and multinuclear platinum complexes are known to induce distinct types of DNA lesions and exhibit different profiles of antitumor activity, in relation to p53 mutational status. In this study, we investigated the cellular effects of exposure to two platinum compounds (cisplatin and the multinuclear platinum complex BBR 3464), in the osteosarcoma cell line, U2-OS, carrying the wild-type p53 gene and capable of undergoing apoptosis or cell cycle arrest in response to diverse genotoxic stresses. In spite of the ability of both compounds to up-regulate p53 at cytotoxic concentrations, exposure to BBR 3464 resulted in cell cycle arrest but only cisplatin was capable of inducing significant levels of apoptosis and phosphorylation at the Ser15 residue of p53. The cisplatin-induced protein phosphorylation, not detectable in cells treated with BBR 3464, was associated with RPA phosphorylation, a specific up-regulation of Bax and down-regulation of p21(WAF1). Cells treated with BBR 3464 displayed a different cellular response with evidence of cytostasis associated with a high induction of p21(WAF1). The regulation of p21(WAF1) after cisplatin or BBR 3464 exposure required a p53 signal, as documented using stable transfectants expressing a dominant-negative form of p53 (175(his)). Taken together, these results indicate that cellular response to different genotoxic lesions (i.e. apoptosis or growth arrest) is associated with a specific recognition of DNA damage and a different p53-mediated signaling pathway. Multinuclear platinum complexes could be regarded as useful tools for investigating the p53-mediated process of cell cycle arrest in response to DNA damage.

Expression of the anti-apoptotic gene survivin correlates with taxol resistance in human ovarian cancer

Stable transfection of human ovarian carcinoma cells with survivin cDNA caused a four- to sixfold increase in cell resistance to taxotere and taxol (two-sided Student's t test, p < 0.05), with a concomitant reduction in the apoptotic response to taxol, but did not affect cell sensitivity to cisplatin or oxaliplatin. Such findings were indirectly supported by similar observations obtained with clinical tumours. In fact, high levels of survivin protein expression (>30% positive cells), detected by immunohistochemistry in 90/124 (73%) advanced ovarian carcinomas, were significantly associated with clinical resistance to a taxol/platinum-based regimen but unrelated to tumour shrinkage following cisplatin-including combinations (non-taxol based). In the 95 patients receiving a taxol/platinum-based regimen, survivin overexpression correlated with a lower clinical or pathologic complete remission rate than absent/low protein expression (43 vs 75%, p = 0.0058 by logistic regression adjusted for tumour stage, histological grade and p53 expression). Conversely, in the 29 cases treated with cisplatin-containing regimens (not taxol based), survivin expression was unrelated to tumour response. Cellular studies and clinical data suggest a direct link between survivin expression and tumour cell susceptibility to taxol.

A role for c-myc in DNA damage-induced apoptosis in a human TP53-mutant small-cell lung cancer cell line

Based on the role of p53 in the control of apoptosis following DNA damage, the status of the TP53 gene has been implicated as a major determinant of tumour responsiveness to cytotoxic therapies. In spite of the high frequency of TP53 mutations, small-cell lung cancer (SCLC) is recognised as one of the most chemoresponsive solid tumours. Since the relevance of the TP53 gene status in the modulation of tumour responsiveness is dependent on the molecular/biological context, in the present study, we have examined the relationship between chemosensitivity and susceptibility to apoptosis of a TP53-mutant human SCLC cell line. The cell line, in spite of TP53 mutation, retained an efficient response to genotoxic stress as documented by cells ability to modulate the p53 protein, arrest in the G1 and G2 phases of the cell cycle and its marked susceptibility to apoptosis following treatment with DNA damaging agents. Exposure to DNA-damaging agents caused an increase of c-Myc, a DNA damage-responsive transcription factor. An analysis of damage-induced apoptosis in the presence of an anti-Fas/CD95 inhibitory antibody indicated that Fas/CD95 was not required for the apoptotic response. The results support an implication of c-myc in sensitising cells to apoptosis, since inhibition of c-Myc expression with an antisense oligodeoxynucleotide (AS-ODN) almost abolished the drug-induced apoptotic response. In conclusion, the present results support a role for c-myc in the induction of apoptosis by genotoxic stress in the absence of a functional p53 and provide new insights into the mechanisms that may influence apoptosis in TP53-mutant cells. Elucidation of this pathway and of the possible cooperation with p53-dependent mechanisms may provide a basis for therapeutic intervention.

Role of apoptosis and apoptosis-related genes in cellular response and antitumor efficacy of anthracyclines

Cellular resistance to anthracyclines is a major limitation of their clinical use in the treatment of human tumors. Resistance to doxorubicin is described as a multifactorial phenomenon involving the overexpression of defense factors and alterations in drug-target interactions. Such changes do not account for all manifestations of drug resistance, in particular intrinsic resistance of solid tumors. Since anthracyclines can induce apoptotic cell death, an alternative promising approach to drug resistance has focused on the study of cellular response to drug-induced DNA damage, with particular reference to the relationship between cytotoxicity/antitumor efficacy and apoptotic response. The evidence that a novel disaccharide analog (MEN 10755), endowed with an improved preclinical activity over doxorubicin, was also more effective as an inducer of apoptosis provided additional insights to better understand the cellular processes that confer sensitivity to anthracyclines. Although the presence or alteration of a single apoptosis-related factor (e.g., p53, bcl-2) is not predictive of the sensitivity/resistance status, the complex interplay among DNA damage-activated pathways is likely an important determinant of tumor cell sensitivity to anthracyclines

p53 gene status and response to platinum/paclitaxel-based chemotherapy in advanced ovarian carcinoma

PURPOSE

The p53 gene plays a critical role in cellular response to DNA damage and has been implicated in the response to platinum compounds in ovarian carcinoma patients. Because taxanes could induce p53-independent apoptosis, we assessed the relevance of p53 gene status to response in ovarian carcinoma patients receiving paclitaxel and platinum-containing chemotherapy.

PATIENTS AND METHODS

Forty-eight previously untreated patients with advanced disease received standard paclitaxel/platinum-based chemotherapy. In tumor specimens collected at the time of initial surgery, before therapy, p53 gene status and expression were examined by single-strand conformation polymorphism, sequence analysis, and immunohistochemical analysis. Microsatellite instability analysis was performed on available samples from 30 patients.

RESULTS

Thirty-four (71%) of the 48 patients had a clinical response. Pathologic complete remission was documented in 13 (27%) of 48 patients. p53 mutations were detected in 29 (60%) of 48 tumors. Among the patients with mutant p53 tumors, 25 patients (86%) responded to chemotherapy. Only nine (47%) of 19 patients with wild-type p53 tumors responded to the same treatment. The overall response rate and the complete remission rate were significantly higher among patients with mutant p53 tumors than among patients with wild-type p53 tumors (P: =.008). Most of the tested tumors not associated with complete remission (10 of 12 tumors) were also characterized by microsatellite instability. The complete remission rate was higher among patients with tumors without microsatellite instability (five of seven patients).

CONCLUSION

In contrast to the limited efficacy of treatment with paclitaxel in combination with standard platinum doses against wild-type p53 ovarian tumors, patients with mutant p53 ovarian tumors were more responsive to paclitaxel-based chemotherapy. The pattern of response to chemotherapy containing paclitaxel is different from that associated with high-dose cisplatin therapy. Determining p53 mutational status can be useful in predicting therapeutic response to drugs effective in ovarian carcinoma.

Yeast mutants as a model system for identification of determinants of chemosensitivity

The fission yeast Schizosaccharomyces pombe and the budding yeast Saccharomyces cerevisiae have become valuable tools for the study of basic cellular functions of eukaryotic cells, including DNA repair mechanisms and cell cycle control. Since the major signaling pathways and cellular processes involved in cellular response to cytotoxic agents are conserved between yeasts and mammalian cells, these simple eukaryotic systems could be excellent models for the identification of molecular/cellular mechanisms of sensitivity to antitumor drugs. We describe relevant biological features of yeast cells and potential applications derived by their genetic manipulation. In particular, we have outlined the role of genes involved in repair processes and in checkpoint control, with specific reference to genes regulating radiation-sensitivity. Specific examples are provided concerning the use of both yeasts in understanding the mechanism of action of platinum compounds and topoisomerase inhibitors. The availability of the genomic sequence of these organisms as well as of new technologies (microarrays, proteomics) is expected to allow the identification of potential drug targets, since the drug discovery process is moving toward a genomic orientation. Among eukaryotic organisms, yeasts are suitable for easy genetic manipulations, and specific genetic alterations are exploitable for assessing the effects of chemotherapeutic agents with different mechanism of action. Although still at an early stage, this fast-moving field shows promise as a novel and potentially useful method for development of target-specific therapeutic approaches.

Apoptosis induced by extracellular glutathione is mediated by H(2)O(2) production and DNA damage

The biochemical basis of the anti-proliferative effect of exogenous glutathione was investigated in A2780 ovarian carcinoma cells. Previous observations have implicated gamma-glutamyl transpeptidase-mediated pro-oxidant reactions as a primary mechanism of the extracellular effects of glutathione. In 2 cell lines (A2780 and IGROV-1), glutathione led to H(2)O(2) production, but only A2780 cells, characterized by low expression of detoxification enzymes, were sensitive to the thiol compound. In A2780 cells, glutathione exposure resulted in DNA single-strand break formation, as measured by alkaline elution. Glutathione-induced DNA damage generated significant levels of apoptosis in A2780 cells, but not in IGROV-1 cells. The capability of glutathione to induce apoptosis was associated with cleavage of poly(ADP-ribose)polymerase and with generation of a low-molecular-weight form of the pro-apoptotic protein bax. In A2780 cells, glutathione exposure was followed by p21 and Bax induction and p53 up-regulation, as expected for genotoxic stress. Consistently, analysis of cell-cycle perturbations demonstrated the occurrence of G(2)M accumulation after exposure to glutathione, similar to what was observed for H(2)O(2). Taken together, these results indicate that the cytotoxic effect of extracellular glutathione, related to membrane metabolism, is mediated by production of H(2)O(2) leading to DNA damage and a cellular response involving p53. These findings might also provide insights into the cellular and molecular determinants of chemosensitivity to DNA damaging agents, as oxidative stress is implicated in p53-dependent apoptosis.

Apical plasma membrane mispolarization of NaK-ATPase in polycystic kidney disease epithelia is associated with aberrant expression of the beta2 isoform

Autosomal dominant polycystic kidney disease (ADPKD) is a common genetic disease of the kidney, characterized by cystic enlargement of renal tubules, aberrant epithelial proliferation, and ion and fluid secretion into the lumen. Previous studies have shown abnormalities in polarization of membrane proteins, including mislocalization of the NaK-ATPase to the apical plasma membranes of cystic epithelia. Apically located NaK-ATPase has previously been shown to be fully functional in vivo and in membrane-grown ADPKD epithelial cells in vitro, where basal-to-apical (22)Na transport was inhibited by application of ouabain to the apical membrane compartment. Studies were conducted with polymerase chain reaction-generated specific riboprobes and polyclonal peptide antibodies against human sequences of alpha1, alpha3, beta1, and beta2 subunits of NaK-ATPase. High levels of expression of alpha1 and beta1 messenger RNA were detected in ADPKD and age-matched normal adult kidneys in vivo, whereas beta2 messenger RNA was detected only in ADPKD kidneys. Western blot analysis and immunocytochemical studies showed that, in normal adult kidneys, peptide subunit-specific antibodies against alpha1 and beta1 localized to the basolateral membranes of normal renal tubules, predominantly thick ascending limbs of Henle's loop. In ADPKD kidneys, alpha1 and beta2 subunits were localized to the apical epithelial cell membranes, whereas beta1 was distributed throughout the cytoplasm and predominantly in the endoplasmic reticulum, but was not seen associated with cystic epithelial cell membranes or in cell membrane fractions. Polarizing, renal-derived epithelial Madin Darby canine kidney cells, stably expressing normal or N-terminally truncated chicken beta1 subunits, showed selective accumulation in the basolateral Madin Darby canine kidney cell surface, whereas c-myc epitope-tagged chicken beta2 or human beta2 subunits accumulated selectively in the apical cell surface. Similarly, human ADPKD epithelial cell lines, which endogenously expressed alpha1 and beta2 NaK-ATPase subunits, showed colocalization at the apical cell surface and coassociation by immunoprecipitation analysis. These results are consistent with a model in which the additional transcription and translation of the beta2 subunit of NaK-ATPase may result in the apical mislocalization of NaK-ATPase in ADPKD cystic epithelia.

The cellular basis of the efficacy of the trinuclear platinum complex BBR 3464 against cisplatin-resistant cells

Multinuclear platinum compounds have been designed to circumvent the cellular resistance to conventional mononuclear platinum-based drugs. In this study we performed a comparative study of cisplatin and of the triplatinum complex BBR 3464 in a human osteosarcoma cell system (U2-OS) including an in vitro selected cisplatin-resistant subline (U2-OS/Pt). BBR 3464 was extremely potent in comparison with cisplatin in U2-OS cells and completely overcame resistance of U2-OS/Pt cells. In both cell lines, BBR 3464 accumulation and DNA-bound platinum were higher than those observed for cisplatin. On the contrary, a low frequency of interstrand cross-links after exposure to BBR 3464 was found. Differently from the increase of DNA lesions induced by cisplatin, kinetics studies indicated a low persistence of interstrand cross-link formation for BBR 3464. Western blot analysis of DNA mismatch repair proteins revealed a marked decrease of expression of PMS2 in U2-OS/Pt cells, which also exhibited microsatellite instability. Studies on DNA mismatch repair deficient and proficient colon carcinoma cells were consistent with a lack of influence of the DNA mismatch repair status on BBR 3464 cytotoxicity. In conclusion, the cytotoxic potency and the ability of the triplatinum complex to overcome cisplatin resistance appear to be related to a different mechanism of DNA interaction (formation of different types of drug-induced DNA lesions) as compared to conventional mononuclear complexes.

Expression of the beta2-subunit and apical localization of Na+-K+-ATPase in metanephric kidney

During kidney organogenesis, the Na+-K+-ATPase pump is not restricted to the basolateral plasma membrane of the renal epithelial cell but is instead either localized to the apical and lateral membrane sites of the early nephron or expressed in a nonpolarized distribution in the newly formed collecting ducts. The importance of Na+-K+-ATPase beta-subunit expression in the translocation of the Na+-K+-ATPase to the plasma membrane raises the question as to which beta-subunit isoform is expressed during kidney organogenesis. Immunocytochemical, Western analysis and RNase protection studies showed that both beta2-subunit protein and beta2 mRNA are expressed in the early gestation to midgestation human metanephric kidney. In contrast, although beta1 mRNA abundance is equivalent to that of the beta2-subunit in the metanephric kidney, the beta1-subunit protein was not detected in early to midgestation metanephric kidney samples. Immunocytochemical analysis revealed that both alpha1- and beta2-subunits were present in the apical epithelial plasma membranes of distal nephron segments of early stage nephrons, maturing loops of Henle, and collecting ducts during kidney development. We also detected a significant increase in alpha1 and beta1 mRNA after birth with a marked reduction in beta2 mRNA abundance associated with an increase in alpha1- and beta1-subunit proteins and loss of beta2 protein expression. These studies support the conclusion that the expression of the beta2-subunit in the fetal kidney may be an important mechanism controlling polarization of the Na+-K+-ATPase pump in the epithelia of the developing nephron during kidney organogenesis.

A framework for building cooperative software agents in medical applications

Exploiting the information technology may have a great impact on improving cooperation and interoperability among the different professionals taking part to the process of delivering health care services. New paradigms are therefore being devised considering software systems as autonomous agents able to help professionals in accomplishing their duties. To this aim those systems should encapsulate the skills for solving a given set of tasks and possess the social ability to cooperate in order to fetch the required information and knowledge. This paper illustrates a methodology facilitating the development of interoperable intelligent software agents for medical applications and proposes a generic computational model for implementing them. That model may be specialized in order to support all the different information and knowledge related requirements of a Hospital Information System. The architecture is being tested for implementing a prototype system able to coordinate the joint efforts of the professionals involved in managing patients affected by Acute Myeloid Leukemia.

A novel trinuclear platinum complex overcomes cisplatin resistance in an osteosarcoma cell system

Multinuclear platinum compounds have been designed to circumvent the cellular resistance to conventional platinum-based drugs. In an attempt to examine the cellular basis of the preclinical antitumor efficacy of a novel multinuclear platinum compound (BBR 3464) in the treatment of cisplatin-resistant tumors, we have performed a comparative study of cisplatin and BBR 3464 in a human osteosarcoma cell line (U2-OS) and in an in vitro selected cisplatin-resistant subline (U2-OS/Pt). A marked increase of cytotoxic potency of BBR 3464 in comparison with cisplatin in U2-OS cells and a complete lack of cross-resistance in U2-OS/Pt cells were found. A detailed analysis of the cisplatin-resistant phenotype indicated that it was associated with reduced cisplatin accumulation, reduced interstrand cross-link (ICL) formation and DNA platination, microsatellite instability, and reduced expression of the DNA mismatch repair protein PMS2. Despite BBR 3464 charge and molecular size, in U2-OS and U2-OS/Pt cells, BBR 3464 accumulation and DNA-bound platinum were much higher than those observed for cisplatin. In contrast, the frequency of ICLs after exposure to BBR 3464 was very low. The time course of ICL formation after drug removal revealed a low persistence of these types of DNA lesions induced by BBR 3464, in contrast to an increase of DNA lesions induced by cisplatin, suggesting that components of the DNA repair pathway handle the two types of DNA lesions differently. The cellular response of HCT116 mismatch repair-deficient cells was consistent with a lack of influence of mismatch repair status on BBR 3464 cytotoxicity. Because BBR 3464 produces high levels of lesions different from ICLs, likely including intra-strand cross-links and monoadducts, the ability of the triplatinum complex to overcome cisplatin resistance appears to be related to a different mechanism of DNA interaction (formation of different types of drug-induced DNA lesions) as compared with conventional mononuclear complexes rather than the ability to overcome specific cellular alterations.

Supporting tools for guideline development and dissemination

This paper describes a methodology for representing clinical practice guidelines and facilitating their introduction into the medical routine. Since this methodology can be exploited in a www environment, it can represent the basis for sharing clinical guidelines both between different institutions and between human and software agents cooperating within a clinical context. In addition, the proposed guideline formalization is intended to deal with patient and organization preferences. This goal is achieved by augmenting the guideline with decision analytic models and by linking the guideline with an organizational model of the clinical setting. The designed framework allows guideline development, tailoring and implementation, real-time access to the guideline prescriptions and guideline validation.

Platelet activation in newborns detected by flow-cytometry

Platelet function was investigated in full-term infants on the first, the fourth and tenth days of life and compared to normal adult controls. Platelet function was analyzed through a new cytofluorimetric technique with two murine monoclonal antibodies, PAC-1 and anti-GMP-140, directed against two membrane proteins expressed on the activated platelets' surface. The percentage of activated platelets detected with PAC-1 and anti-GMP-140 was evaluated at basal condition and after in vitro stimulation with a weak agonist (ADP) and a strong Txa2 analogue inducer (U 46619). At day 1 platelet activation at basal condition was negligible and similar to adult controls both with PAC-1 (1.2 vs 1.1%) and anti-GMP-140 (2.6 vs. 3.3%). On the contrary, after ADP stimulation the percentage of PAC-1-positive activated platelets was significantly reduced in neonates compared to adults (22 vs. 66%; p < 0.001) and even more after U 46619 (11 vs. 72%; p < 0.001). The percentage of anti-GMP-140-positive activated platelets behaved similarly after adding both ADP (26 vs. 46%; p < 0.01) and U 46619 (37 vs. 67%; p < 0.001). The reduced platelet activation after ADP and U 46619 persisted at day 4 both with PAC-1 and with anti-GMP-140. On the contrary, at day 10 newborn platelets analyzed with anti-GMP-140 behaved similarly to the adult ones both at basal condition and after stimulation with ADP or U 46619 (6 vs. 3% at basal state, 42 vs. 46% after ADP addition, and 55 vs. 67% after U 46619). These data demonstrate that the reduced platelet activation present in newborns is restored by the tenth day after birth.

Hemostatic parameters and platelet activation by flow-cytometry in normal pregnancy: a longitudinal study

Nineteen pregnant women with uncomplicated pregnancies were studied during the first, second, and third trimesters. We measured the following hemostatic parameters: prothrombin time, activated partial thromboplastin time, fibrinogen, antithrombin III, protein C, protein S, platelet number and volume. Platelet function was examined by a cytofluorimetric method, using an anti-GPM-140 antibody which is directed against a platelet alpha granule membrane protein. Activated platelets were expressed as a percentage of the GMP-140-positive platelets over total platelets. Fibrinogen levels showed a steady increase during pregnancy; conversely prothrombin time, activated partial thromboplastin time, protein C, and antithrombin III showed no significant modifications and remained within the reference range. There was a decrease of protein S activity throughout pregnancy, although protein S antigen did not follow this trend. The decrease occurred early in pregnancy and persisted during the second and third trimesters, reaching a stable plateau. We observed no platelet volume change or activation: the percentage of activated platelets was within the normal reference range, even in late pregnancy.

Maternal and fetal platelet activation in normal pregnancy

OBJECTIVE

To study the platelet activation phase in normal pregnant women and their fetuses, both in vivo under basal conditions and in vitro after stimulation by adenosine diphosphate (ADP), a weak agonist, and U46619, a strong one.

METHODS

Platelet function was investigated in 39 normal pregnant women and their fetuses undergoing fetal blood sampling at 18-37 weeks' gestation, using flow cytometry and the anti-GMP140 monoclonal antibody. This combined technique allows platelets to be investigated in small aliquots of whole blood, and it detects platelet secretion regardless of aggregation. In all cases, the percentage of activated platelets was determined under basal conditions and after addition of platelet agonists: ADP at concentrations of 10 and 50 mumol/L, and U46619, a stable analogue of thromboxane A2, at 1 mumol/L.

RESULTS

Compared to nonpregnant controls, pregnant women had a significantly lower percentage of activated platelets after addition of U46619 (P = .02). Compared to their mothers, fetuses had significantly inferior platelet activation after addition of both platelet-activating factors at all concentrations used (ADP 10 mumol/L, P < .0001 and ADP 50 mumol/L, P < .0001; U46619, P < .0001). Maternal and fetal platelet activation did not change with duration of gestation. In the fetus, the percentage of activated platelets did not correlate with hematocrit, pH, or oxygen pressure, but it correlated significantly with platelet count after addition of U46619 (r = 0.45, P = .006).

CONCLUSIONS

Decreased platelet activation in both pregnant women and fetuses suggests the action of a plasma factor that selectively inhibits prostaglandin-dependent activation. Prostacyclin, which is known to decrease platelet aggregation and release reactions caused by agonists, might have a greater inhibitory effect in the fetus than in the mother, or be present in larger amounts in the fetus.

Functional protein S in women with lupus anticoagulant inhibitor

Protein C (PC) and protein S (PS) are components of a potent, natural anticoagulant system. A deficiency of one of these two inhibitors is associated with thrombotic events in young people. A significant reduction in functional PS activity has been observed during normal pregnancy, and recurrent fetal loss may occur in women with lupus anticoagulant (LA) inhibitor. We measured functional PS activity and free PS antigen in 16 non pregnant patients with LA inhibitor and in 17 normal women as controls. A significant difference was observed between patients and controls in functional PS activity (65 +/- 23% vs 87 +/- 15%, p = 0.02) but not in free PS antigen (88 +/- 17% vs 93 +/- 17%). Functional PS activity decreased only in six patients (37%). Removal of IgG from plasma reduced the difference in functional PS activity between patients and controls. Immunologic IgG levels did not correlate with anti-phospholipid antibodies (APA) activities, activated partial thromboplastin time/kaolin clotting time (aPTT/KCT) data or functional PS activity.