Detailed three-dimensional visualization of resilin in the exoskeleton of arthropods using confocal laser scanning microscopy

Resilin is a rubber-like protein found in the exoskeleton of arthropods. It often contributes large proportions to the material of certain structures in movement systems. Accordingly, the knowledge of the presence and distribution of resilin is essential for the understanding of the functional morphology of these systems. Because of its specific autofluorescence, resilin can be effectively visualized using fluorescence microscopy. However, the respective excitation maximum is in the UV range, which is not covered by the lasers available in most of the modern commercial confocal laser scanning microscopes. The goal of this study was to test the potential of confocal laser scanning microscopy (CLSM) in combination with a 405 nm laser to visualize and analyse the presence and distribution of resilin in arthropod exoskeletons. The results clearly show that all resilin-dominated structures, which were visualized successfully using wide-field fluorescence microscopy (WFM) and a 'classical' UV excitation, could also be visualized efficiently with the proposed CLSM method. Furthermore, with the application of additional laser lines CLSM turned out to be very appropriate for studying differences in the material composition within arthropod exoskeletons in great detail. As CLSM has several advantages over WFM with respect to detailed morphological imaging, the application of the proposed CLSM method may reveal new information about the micromorphology and material composition of resilin-dominated exoskeleton structures leading to new insights into the functional morphology and biomechanics of arthropods.

Molecular mechanisms of cisplatin resistance

Platinum-based drugs, and in particular cis-diamminedichloroplatinum(II) (best known as cisplatin), are employed for the treatment of a wide array of solid malignancies, including testicular, ovarian, head and neck, colorectal, bladder and lung cancers. Cisplatin exerts anticancer effects via multiple mechanisms, yet its most prominent (and best understood) mode of action involves the generation of DNA lesions followed by the activation of the DNA damage response and the induction of mitochondrial apoptosis. Despite a consistent rate of initial responses, cisplatin treatment often results in the development of chemoresistance, leading to therapeutic failure. An intense research has been conducted during the past 30 years and several mechanisms that account for the cisplatin-resistant phenotype of tumor cells have been described. Here, we provide a systematic discussion of these mechanism by classifying them in alterations (1) that involve steps preceding the binding of cisplatin to DNA (pre-target resistance), (2) that directly relate to DNA-cisplatin adducts (on-target resistance), (3) concerning the lethal signaling pathway(s) elicited by cisplatin-mediated DNA damage (post-target resistance) and (4) affecting molecular circuitries that do not present obvious links with cisplatin-elicited signals (off-target resistance). As in some clinical settings cisplatin constitutes the major therapeutic option, the development of chemosensitization strategies constitute a goal with important clinical implications.

Structure of a laccase-mediated product of coupling of 2,4-diamino-6-nitrotoluene to guaiacol, a model for coupling of 2,4,6-trinitrotoluene metabolites to a humic organic soil matrix

This work presents laccase-mediated model reactions for coupling of reduced 2,4,6-trinitrotoluene (TNT) metabolites to an organic soil matrix. The structure of an isolated coupling product of 2,4-diamino-6-nitrotoluene (2,4-DANT) to guaiacol as humic constituent was determined. Among several structures, the compound was identified conclusively to be the trinuclear coupling product 5-(2-amino-3-methyl-4-nitroanilino)-3,3(prm1)-dimethoxy-4,4(prm1)-diphenoqu inone. The compound has a weight of 409 g mol(sup-1) and may serve as a model reaction for the biogenic formation of bound residues in soil from TNT by coupling aminotoluenes (reduced TNT metabolites) to humic constituents. A linear correlation of the substrate consumption to the enzyme activity was detected. Based on this observation, the described reaction of 2,4-DANT coupling to guaiacol may be used for determination of laccase activity since the reaction was not inhibited by other compounds of culture supernatants. We propose a two-step mechanism for the coupling reaction because 2,4-DANT was not transformed by laccases in the absence of guaiacol and guaiacol oxidation was independent of the presence of 2,4-DANT. The first reaction step is a laccase-mediated dimerization of two guaiacol monomers with subsequent oxidation to a diphenoquinone. The second step is the nucleophilic addition of 2,4-DANT to the ortho position of the carbonyl group of the diphenoquinone structure.

A phase IB study of ABT-751 in combination with docetaxel in patients with advanced castration-resistant prostate cancer

BACKGROUND

This study investigated the safety, pharmacokinetics (PK) and clinical antitumor activity of ABT-751, a novel sulfonamide antimitotic and vascular disrupting agent, in combination with docetaxel (Taxotere) in patients with castration-resistant prostate cancer (CRPC).

PATIENTS AND METHODS

Patients received docetaxel (60-75 mg/m(2)) i.v. on day 1 and ABT-751 (100-200 mg) orally daily for 14 days, repeated every 3 weeks for up to 10 times on four escalating dose levels (DLs).

RESULTS

Thirty-two patients received a median of 8.5 treatment cycles (range 1-10). One of six patients on DL 3 (D 60 mg/m(2) + A 200 mg) and 4 (D 75 mg/m(2) + A 200 mg) experienced dose-limiting toxicity, and both DLs were expanded. Overall, severe adverse events occurred more commonly on DL 4 than 3 (47% versus 18% of patients). PK data for docetaxel and ABT-751 were similar to reported literature. Best post-treatment prostate-specific antigen decline of > or =50% occurred in 60% and objective responses occurred in 45% of patients. Median overall survival was 24 months (95% confidence interval 8.3-37.7 months).

CONCLUSIONS

The combination of ABT-751 and docetaxel is safe and active in CRPC. Based on the cumulative safety analysis, the recommended phase II dose of ABT-751 is 200 mg daily with docetaxel 60 mg/m(2) for this patient population.

Effect of adjuvant chemotherapy on survival in FNCLCC grade 3 soft tissue sarcomas: A multivariate analysis of the French Sarcoma Group database

10504

Background: The SMAC meta-analysis failed to demonstrate that adjuvant chemotherapy (AC) significantly improves overall survival (OS) in adult patients with localised resectable soft-tissue sarcoma (STS). We report here the analysis of the impact of AC in the population of STS patients included in the prospective database of the French Sarcoma Group. Methods: Between 1980 and 1999, 2,029 pts with STS were admitted to one of the 20 tertiary cancer centers of the GSF for the management of a first tumoral event and were included prospectively in a comprehensive database. 152 pts were excluded from the study because of metastatic disease at diagnosis. All the cases were reviewed by the pathology subcommittee of the GSF. Tumor grade was assessed according to the FNCLCC system based on tumor differentiation, mitotic count, and necrosis. Results: 283 pts (14.5%) had grade 1, 736 (39.5%) grade 2 and 858 (46%) grade 3 tumors. 1,102 pts (59%) had extremity tumors. The commonest pathological subtypes were MFH 22.5%, liposarcoma 18%, leiomyosarcoma 13%, and synovial sarcoma 10%. 1,122 pts (60%) received adjuvant radiotherapy. AC was delivered in 16 grade 1 pts (6%), 167 grade 2 pts (23%) and 323 grade 3 pts (38%). The majority of patients who received AC had tumors with a deep topography (91%) and/or > 5 cm (75%) and/or located in the limbs (61%). The median follow-up was 9 years. The 5 year-OS was 90% for grade 1 pts, 63% for grade 2 pts and 46% for grade 3 pts. On multivariate analysis ( table 1 ), AC was strongly associated with improved metastasis-free survival (MFS) (5 year MFS: 53% vs 47%, HR 0.7 [0.5–0.9], p=0.003) and overall survival (OS) (5 year OS: 56% vs 44%, HR 0.7 [0.5–0.8], p=0.004) in grade 3 pts. This association was not observed in grade 2 pts (5 year MFS: 73% vs 72%, HR 0.9 [0.6–1.4], p=0.9; 5 year OS: 73% vs 65%, HR 0.7 [0.5–1.1]). Conclusions: This large cohort-based analysis with long-term follow-up indicates that FNCLCC grade 3 pts are likely to benefit from AC. [Table: see text]

[Table: see text]

A phase II trial of voreloxin in women with platinum-resistant ovarian cancer

5559

Background: Voreloxin is a naphthyridine analog that intercalates DNA and inhibits topoisomerase II, inducing apoptosis. Clinical activity has been observed in ovarian cancer and AML. Results are reported from a fully enrolled phase II study of 3 dose levels of single agent voreloxin in patients (pts) with 1° or 2° platinum-resistant or refractory ovarian cancer. Methods: Pts may have received ≤ 3 prior platinum regimens plus one additional non-platinum regimen. PS of 0–1 was required. Voreloxin regimens: Cohort A 48 mg/m2q3weeks (wk) (N = 65), Cohort B 60 mg/m2q4wk (N = 35), and Cohort C 75 mg/m2q4wk (N = 35) by short IV infusion. BRCA status is reported by pt consent. Results: Cohort A: 2CRs, 5PRs; ORR 11%; median PFS 82 days (52–98 days 95%CI); Cohort B: 1CR, 3PRs; ORR 11%, median PFS too early to evaluate (TETE); Cohort C - TETE. Cohort A: Febrile neutropenia (FN) incidence was low (8%). Other common G3 or G4 AEs reported (≥ 5%) were fatigue (14%) and nausea (5%). Dose delays or reductions (40%) occurred typically at Cycle 1, largely due to neutropenia. Cohort B: Dose was increased to 60 mg/m2 and dosing interval was lengthened to 4 wk, maintaining dose intensity (DI) and allowing adequate time for marrow recovery. ANC dosing criterion was changed from ANC ≥ 1,500 to ≥ 1,000. There was a marked decrease in dose delays and reductions (14%) with only 3% incidence of FN. Common G3 or 4 AEs reported (≥ 5%) were fatigue (11%) and nausea (5%). The safety profile supported further dose escalation to 75 mg/m2q4wk (Cohort C- DI increased by 25%). Data are TETE. Conclusions: Preliminary data suggest Cohorts A and B have similar safety and efficacy profiles as anticipated based on comparable DI. Fewer dose reductions and delays occurred in Cohort B, due to revised dosing criteria and increased cycle length to 4 wk. Accrual to Cohort C is complete. Efficacy and safety data for all cohorts will be reported.

[Table: see text]

Confocal laser scanning microscopy: using cuticular autofluorescence for high resolution morphological imaging in small crustaceans

The utility of cuticular autofluorescence for the visualization of copepod morphology by means of confocal laser scanning microscopy (CLSM) was examined. Resulting maximum intensity projections give very accurate information on morphology and show even diminutive structures such as small setae in detail. Furthermore, CLSM enables recognition of internal structures and differences in material composition. Optical sections in all layers and along all axes of the specimens can be obtained by CLSM. The facile and rapid preparation method bears no risk of artefacts or damage occurring to the preparations and the visualized specimens can be used for later analyses allowing for the investigation of irreplaceable type specimens or parts of them. These features make CLSM a very effective tool for both taxonomical and ecological studies in small crustaceans; however, the maximum thickness of the specimens is limited to a few hundred micrometers. Three-dimensional models based on CLSM image stacks allow observation of the preparations from all angles and can permit, improve and speed up studies on functional morphology. The visualization method described has a strong potential to become a future standard technique in aquatic biology due to its advantages over conventional light microscopy and scanning electron microscopy.

Distinct promoters mediate constitutive and inducible Bcl-XL expression in malignant lymphocytes

Bcl-X(L) is a Bcl-2-related survival protein that is essential for normal development. Bcl-X(L) expression is rapidly induced by a wide range of survival signals and many cancer cells constitutively express high levels. The Bcl-X gene has a complex organization with multiple promoters giving rise to RNAs with alternate 5' non-coding exons. Here we have investigated the mechanisms that control basal and induced expression of Bcl-X(L) in B-lymphoma cells. Antisense experiments demonstrated that Bcl-X(L) was essential for survival of Akata6 B-lymphoma cells. The levels of RNAs containing the IB Bcl-X non-coding exon, derived from the distal 1B promoter, correlated with basal expression of Bcl-X(L) in primary malignant B cells and this promoter was highly active in B-cell lines. The activity of this promoter was largely dependent on a single Ets binding site and Ets family proteins were bound at this promoter in intact cells. CD40 ligand (CD40L)-induced cell survival was associated with increased Bcl-X(L) expression and accumulation of exon IA-containing RNAs, derived from the proximal 1A promoter. Nuclear factor-kappaB (NF-kappaB) inhibition prevented induction of Bcl-X(L) protein and exon IA-containing RNAs by CD40L. Therefore, the distal Bcl-X 1B promoter plays a critical role in driving constitutive expression-mediated via Ets family proteins in malignant B cells, whereas NF-kappaB plays a central role in the induction of Bcl-X(L) in response to CD40 signalling via the proximal 1A promoter.

The Combination of Raltitrexed (Tomudex) and Mitomycin-C in the Treatment of Advanced Colorectal Cancer — A Phase II Study

AIMS

To investigate the combination of raltitrexed and mitomycin-C as first-line chemotherapy treatment in patients with advanced colorectal cancer.

MATERIALS AND METHODS

A phase II study.

RESULTS

In total, 22 patients were treated with a combination of raltitrexed 3 mg/m2 every 3 weeks and mitomycin-C 7 mg/m2 every 6 weeks for up to 24 weeks. The study was closed early for safety reasons as there were three unexpected treatment-related deaths. The overall response rate was 20%, and a further 40% achieved stable disease. The median time to progression was 3.9 months and the median overall survival time was 11.6 months.

CONCLUSION

Owing to the potential for increased toxicity, the combination of raltitrexed and mitomycin-C cannot be recommended as first-line treatment in patients with advanced colorectal cancer.

Detection of the synovial sarcoma translocation t(X;18) (SYT;SSX) in paraffin-embedded tissues using reverse transcriptase-polymerase chain reaction: a reliable and powerful diagnostic tool for pathologists. A molecular analysis of 221 mesenchymal tumors fixed in different fixatives

Synovial sarcoma (SS) is a relatively rare sarcoma, which may be confused with several other mesenchymal and nonmesenchymal lesions. It bears the t(X;18) (SYT;SSX) translocation, which seems to be specific for this tumor type and can be detected in paraffin-embedded tissue, using reverse transcriptase-polymerase chain reaction (RT-PCR). However, the specificity and sensitivity of this detection method have rarely been examined in a large series. Using RT-PCR, we examined 250 mesenchymal and nonmesenchymal, benign and malignant, paraffin-embedded lesions for the SS t(X;18) (SYT-SSX) translocation. PCR products were obtained from 221 tumors (88.5%). There were 135 non-SS tumors, 22 biphasic, and 64 monophasic spindle/round cell SS, of which 10 were cytogenetically confirmed as t(X;18)-positive. SYT-SSX gene fusion transcripts were detected in the SS tumor category only (100% specificity), including 100% of the biphasic SS and 86% of monophasic spindle/round cell SS. Nine tumors originally diagnosed as SS were t(X;18) (SYT-SSX)-negative. Following reassessment, only 3 of these tumors showed clinicopathologic, immunohistochemical, and/or ultrastructural features consistent with that diagnosis, thus raising the overall detection sensitivity to 96%. With regard to the potential adverse effect of the fixatives used, PCR products were obtained in 100%, 91.5%, 90.5%, and 0% of tumors fixed with AFA, buffered formalin, Holland Bouin, and conventional Bouin's fluid, respectively. This study shows that the detection of the SS t(X;18) (SYT-SSX) in paraffin-embedded tissue is feasible with a 100% specificity and an overall 96% sensitivity, provided non-Bouin's fluid fixation is used.

Mass spectrometric mapping of ion channel proteins (porins) and identification of their supramolecular membrane assembly

Mass spectrometric peptide mapping, particularly by matrix-assisted laser desorption-ionization (MALDI-MS), has recently been shown to be an efficient tool for the primary structure characterization of proteins. In combination with in situ proteolytic digestion of proteins separated by one- and two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), mass spectrometric peptide mapping permits identification of proteins from complex mixtures such as cell lysates. In this study we have investigated several ion channel membrane proteins (porins) and their supramolecular assembly in mitochondrial membranes by peptide mapping in solution and upon digestion in the gel matrix. Porins are integral membrane proteins serving as nonspecific diffusion pores or as specific systems for the transport of substrates through bacterial and mitochondrial membranes. The well-characterized porin from Rhodobacter capsulatus (R.c.-porin) has been found to be a native trimeric complex by the crystal structure and was used as a model system in this study. R.c.-porin was characterized by MALDI-MS peptide mapping in solution, and by direct in situ-gel digestion of the trimer. Furthermore, in this study we demonstrate the direct identification of the noncovalent complex between a mitochondrial porin and the adenine nucleotide translocator from rat liver, by MALDI-MS determination of the specific peptides due to both protein sequences in the SDS-PAGE gel band. The combination of native gel electrophoresis and mass spectrometric peptide mapping of the specific gel bands should be developed as a powerful tool for the molecular identification of protein interactions.

Screening for fungi intensively mineralizing 2,4,6-trinitrotoluene

Within a screening program, 91 fungal strains belonging to 32 genera of different ecological and taxonomic groups (wood- and litter-decaying basidiomycetes, saprophytic micromycetes) were tested for their ability to metabolize and mineralize 2,4,6-trinitrotoluene (TNT). All these strains metabolized TNT rapidly by forming monoaminodinitrotoluenes (AmDNT). Micromycetes produced higher amounts of AmDNT than did wood- and litter-decaying basidiomycetes. A significant mineralization of [14C]TNT was only observed for certain wood- and litter-decaying basidiomycetes. The most active strains, Clitocybula dusenii TMb12 and Stropharia rugosa-annulata DSM11372 mineralized 42% and 36% respectively of the initial added [14C]TNT (100 microM corresponding to 4.75 microCi/l) to 14CO2 within 64 days. Micromycetes (deuteromycetes, ascomycetes, zygomycetes) proved to be unable to mineralize [14C]TNT significantly.

Are childhood misbehavior and physical illness factors in the development of self-defeating personality

49 undergraduate men and 45 women took Schill's 1990 Self-defeating Personality Scale and answered questions about their physical health and misbehavior as children and the amount of attention such behavior elicited from their parents. No support was found for the idea that individuals who currently score more self-defeating had been more likely to engage in such behavior or had been able to gain attention thereby. In fact, these people reported getting less rather than more attention from parents when they were physically ill. Results were discussed as consistent with prior findings wherein self-defeating individuals have described their parents as being nonsupportive, inconsistent, and rejecting.

Inhibition of the lignin peroxidase of Phanerochaete chrysosporium by hydroxylamino-dinitrotoluene, an early intermediate in the degradation of 2,4,6-trinitrotoluene

The ability of the white rot fungus Phanerochaete chrysosporium to mineralize 2,4,6-trinitrotoluene (TNT) was studied in the concentration range of 0.36 to 20.36 mg/liter. The initial rate of 14CO2 formation was 30% in 4 days at 0.36 mg of [14C]TNT per liter and decreased to 5% in 4 days at 20.36 mg of [14C]TNT per liter. Such a pronounced inhibition was not observed when a mixture of [14C]2-amino-4,6-dinitrotoluene and [14C]4-amino-2,6-dinitrotoluene was used as a substrate. 2-Hydroxylamino-4,6-dinitrotoluene and its isomer 4-hydroxylamino-2,6-dinitrotoluene were identified as the first detectable degradation products of TNT. Their transient accumulation correlated with the inhibition of TNT degradation and of the veratryl alcohol oxidase activity of lignin peroxidase. With purified lignin peroxidase H8, it could be shown that the two isomers of hydroxylamino-dinitrotoluene were oxidized by lignin peroxidase. The corresponding nitroso-dinitrotoluenes apparently were formed, as indicated by the formation of azoxy-tetranitrotoluenes.

Isolierung und spektroskopische Charakterisierung des Pyoverdin-Chromophors sowie seines 5-Hydroxy-Analogen [1] / Isolation and Spectroscopic Characterization of the Pyoverdin Chromophore and of Its 5-Hydroxy Analogue [1]

The isolation of the common chromophore of the pyoverdins isolated from iron-deficient cultures of fluorescent Pseudomonas strains and of its 5-hydroxy analogue as well as the spectroscopic characterization of the two compounds is described.

[Sympathetic activity in terminal renal failure and kidney transplants]

Blood pressure as well as noradrenaline, creatinine and electrolytes in blood and urine were compared in normal controls (n = 25), patients with chronic renal failure (n = 39), patients with continuous ambulatory peritoneal dialysis (CAPD) (n = 28) and haemodialysis patients before and after renal transplantation (n = 63). The average blood pressures of the control group and the CAPD patients were lower than those of the renal failure patients without and with haemodialysis. After renal transplantation elevated blood pressure normalised in 18% within the following 6 months. In all groups of patients with renal failure the mean noradrenaline plasma concentration was increased more than three-fold of normal values: 1,470 pg/ml in patients with chronic renal failure, 1,366 pg/ml in CAPD patients and 1,284 pg/ml in patients with haemodialysis. No correlation was found between these elevated noradrenaline plasma levels and blood pressure. However, there was a significant correlation between noradrenaline excretion and sodium excretion. Compared to the controls, the urine excretion of noradrenaline was significantly lower in patients with chronic renal failure and almost zero in patients with dialysis treatment. Two days after renal transplantation the mean noradrenaline urine excretion increased to 15.7 +/- 1.8 micrograms/day and 4 days after transplantation the noradrenaline plasma concentration decreased to 592 +/- 155 pg/ml. Nine months after renal transplantation the creatinine clearance was 76 ml/min and the mean noradrenaline plasma concentration 438 +/- 153 pg/ml. It is concluded that in chronic renal failure the level of noradrenaline plasma concentration is dependent on renal function.