Oxidative stress induced by ochratoxin A in LLC-PK1 cell line and the chemoprotective effects of carnosic acid

Mycotoxins are secondary metabolites of various moulds that contaminate several alimentary substrates. One of the most dangerous of these is ochratoxin A (OTA). Reactive oxygen species (ROS) play an important role in the toxicity mechanism of OTA, so the use of natural or synthetic free radical scavengers could be a potential chemopreventive strategy. Carnosic acid (CA) is the major polyphenolic compound present in rosemary plants. This work aimed to determine whether CA could counteract OTA-induced cell damage. Free radical scavenging properties of CA were chemically determined at pH 7.4. Cytotoxicity of CA and OTA on LLC-PK1 cells, and the protective effects of CA, were assessed using the Alamar Blue test. The effects in vitro of CA pre-treatment on the production of ROS, the DNA oxidation and the induction of apoptosis induced by OTA were studied. It was found that CA has free radical scavenging properties at both the considered pH values. Moreover, a pre-treatment of 24 h with 10, 20 and 30 µM CA is able to reduce OTA-induced cytotoxicity; a pre-treatment of 24 h with 20 and 30 µM CA achieved ROS reduction and with 30 µM CA decreased the OTA-induced increase of 8-OH-2'-deoxyguanosine and of DNA fragmentation in LLC-PK1. These findings suggest a starting point to develop alimentary strategies against OTAinduced cell damage. Moreover, our results provide further evidence that oxidative stress plays an important role in the OTA cytotoxicity mechanism.

Ependymal stem cells divide asymmetrically and transfer progeny into the subventricular zone when activated by injury

Evidence is presented to show that cells of the ependymal layer surrounding the ventricles of the mammalian (rat) forebrain act as neural stem cells (NSCs), and that these cells can be activated to divide by a combination of injury and growth factor stimulation. Several markers of asymmetric cell division (ACD), a characteristic of true stem cells, are expressed asymmetrically in the ependymal layer but not in the underlying subventricular zone (SVZ), and when the brain is treated with a combination of local 6-hydroxydopamine (6-OHDA) with systemic delivery of transforming growth factor-alpha (TGFalpha), ependymal cells divide asymmetrically and transfer progeny into the SVZ. The SVZ cells then divide as transit amplifying cells (TACs) and their progeny enter a differentiation pathway. The stem cells in the ependymal layer may have been missed in many previous studies because they are usually quiescent and divide only in response to strong stimuli.

Nitric oxide and prostaglandins – important players in endothelin-1 induced myocardial distensibility

This study investigated whether endothelin (ET)-1-induced increase in myocardial distensibility is preserved in heart failure (HF) and whether it is modulated by nitric oxide (NO) and prostaglandins. New Zealand white rabbits were treated with doxorubicin (1 mg/kg, intravenously twice a week for 8 weeks, DOX-HF group) or saline (control group). Effects of ET-1 (0.1, 1, 10 nM) were tested in papillary muscles from the DOX-HF group and a control group in the presence of: i) intact endocardial endothelium (EE); ii) damaged EE; iii) NG -nitro-L-arginine (L-NNA; NO synthase inhibitor), and iv) indomethacin (INDO; cyclooxygenase inhibitor). In the presence of an intact EE, ET-1 promoted concentration-dependent positive inotropic and lusitropic effects that were maintained after damaging the EE, in the presence of L-NNA or INDO and in the DOX-HF Group. ET-1 reduced resting tension at the end of the isometric twitch (increased diastolic distensibility) by 3.2±1.3 %, 6.0±1.6 % and 8.8±2.7 % (at 0.1, 1 and 10 nM, respectively), in muscles with intact EE, effect that was completely abolished after damaging EE, in the presence of L-NNA or INDO or in the DOX-HF Group. This study demonstrated that the increase in myocardial distensibility induced by ET-1 is absent in HF and is dependent of NO and prostaglandin release.

Measurement of nonlinear absorption coefficients of organic materials by mode-mismatched Z-scan thermal lensing technique

We evaluate a new pump-probe mode-mismatched thermal lens (TL) scheme for the measurement of nonlinear absorption in nitrobenzene, benzene, and chloroform. In this new scheme the pump beam is focused in the presence of a collimated probe beam. Values of the nonlinear absorption coefficients of the materials studied for the wavelength of 532 nm are reported, and we compare the proposed technique with the well-known open Z-scan method.

Basal cell carcinoma of the nose requiring amputation arising after irradiation for childhood hemangioma

A 49-year-old female, who had undergone irradiation at six years of age as a treatment for a cutaneous nasal hemangioma, developed later a devastating basal cell carcinoma requiring sub-amputation of the nose and subsequent reconstruction with a pre-expanded forehead flap. Basal cell carcinomas are now frequently reported as late sequelae of previous low-dose irradiations after 10-20 years, and patients should be aware of this possible evolution.

A simple chromosomal marker can reliably distinguishes Poncirus from Citrus species

Several chromosome types have been recognized in Citrus and related genera by chromomycin A(3 )(CMA) banding patterns and fluorescent in situ hybridization (FISH). They can be used to characterize cultivars and species or as markers in hybridization and backcrossing experiments. In the present work, characterization of six cultivars of P. trifoliata ("Barnes", "Fawcett", "Flying Dragon", "Pomeroy", "Rubidoux", "USDA") and one P. trifoliata x C. limonia hybrid was performed by sequential analyses of CMA banding and FISH using 5S and 45S rDNA as probes. All six cultivars showed a similar CMA(+) banding pattern with the karyotype formula 4B + 8D + 6F. The capital letters indicate chromosomal types: B, a chromosome with one telomeric and one proximal band; D, with only one telomeric band; F, without bands. In situ hybridization labeling was also similar among cultivars. Three chromosome pairs displayed a closely linked set of 5S and 45S rDNA sites, two of them co-located with the proximal band of the B type chromosomes (B/5S-45S) and the third one co-located with the terminal band of a D pair (D/5S-45S). The B/5S-45S chromosome has never been found in any citrus accessions investigated so far. Therefore, this B chromosome can be used as a marker to recognize the intergeneric Poncirus x Citrus hybrids. The intergeneric hybrid analyzed here displayed the karyotype formula 4B + 8D + 6F, with two chromosome types B/5S-45S and two D/5S-45S. The karyotype formula and the presence of two B/5S-45S chromosomes clearly indicate that the plant investigated is a symmetric hybrid. It also demonstrates the suitability of karyotype analyses to differentiate zygotic embryos or somatic cell fusions involving trifoliate orange germplasm.

Tumor stem cell vaccine for NSCLC and GBM-assessment of feasibility, adverse events and efficacy

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Background: Only a small part of the total cell population of a malignancy has the potential to grow and regenerate the total tumor mass. The rest are only differentiated forms of those stem cells. This biologic characteristic seems to be responsible for the failure to achieve long term remission for several peptide based vaccines. Method: To overcome this obstacle, we have established a technique that uses tumor stem cells (TSC) to develop a TSC-B cell vaccine. To test efficacy and best administration form of this vaccine, we have proceeded as follow: First: Pieces from total or partial resections of GBM or NSCLC were mechanically dissociated to a single cell suspension. Cells were cultured in an appropriate tissue culture medium and allowed to grow for two weeks or until they reach a semi confluent stage. Then, cells were harvested and re-seeded. This procedure was repeated 6 to 24 weeks according to vitality and growth characteristics of cells. Finally, Tumor cells were fused with autologous B cells. The hybrid was kept in culture and used for an intra lymph node immunization every 3 weeks. To potentiate its action, 3 days prior to its administration we co-incubated the hybrid with either autologous dendritic cells or autologous mononuclear cells. Adverse events were evaluated by the “Common terminology criteria for Adverse Events (AE), 2004” developed by NIH. Definitions are available on the web at http://ctep.cancer.gov/reporting/ctc.html . Clinical efficacy of this procedure was evaluated according RESIST criteria for NSCLC and a combination of MRI and spectroscopy for GBM. Results: At present 8 patients with GBM with post surgical second relapse and who had received complete radiotherapy doses were treated. We have also treated 6 patients with NSCLC:4 with minimal residual disease and 2 with measurable residual disease. Patients have presented minor adverse events, mainly referred to inflammation of the injection site. The median survival rates registered to the present are 22 months for GBM patients and 3 years for patients with stage IV NSCLC who had minimal residual disease at the beginning of the treatment. Conclusion: A tumor stem cell vaccine seems to be a feasible and effective therapy with very low toxicity for the treatment of advanced GBM and NSCLC patients.

No significant financial relationships to disclose.

Mitotic Microtubule Development and Histone H3 Phosphorylation in the Holocentric Chromosomes of Rhynchospora Tenuis (Cyperaceae)

In the present work we report the phosphorylation pattern of histone H3 and the development of microtubular structures using immunostaining techniques, in mitosis of Rhynchospora tenuis (2n = 4), a Cyperaceae with holocentric chromosomes. The main features of the holocentric chromosomes of R. tenuis coincide with those of other species namely: the absence of primary constriction in prometaphase and metaphase, and the parallel separation of sister chromatids at anaphase. Additionaly, we observed a highly conserved chromosome positioning at anaphase and early telophase sister nuclei. Four microtubule arrangements were distinguished during the root tip cell cycle. Interphase cells showed a cortical microtubule arrangement that progressively forms the characteristic pre-prophase band. At prometaphase the microtubules were homogeneously distributed around the nuclear envelope. Metaphase cells displayed the spindle arrangement with kinetochore microtubules attached throughout the entire chromosome extension. At anaphase kinetochoric microtubules become progressively shorter, whereas bundles of interzonal microtubules became increasingly broader and denser. At late telophase the microtubules were observed equatorially extended beyond the sister nuclei and reaching the cell wall. Immunolabelling with an antibody against phosphorylated histone H3 revealed the four chromosomes labelled throughout their entire extension at metaphase and anaphase. Apparently, the holocentric chromosomes of R. tenuis function as an extended centromeric region both in terms of cohesion and H3 phosphorylation.

Acetylcholinesterase and molecular interactions at the neuromuscular junction

The efficiency and the tight control of neurotransmission require the accumulation of synaptic proteins in discrete domains. In neuromuscular junctions, the main form of acetylcholinesterase (AChE) is a hetero-oligomer in which the catalytic subunits are associated to a specific collagen, ColQ. This structural protein is responsible for the insertion and the accumulation of AChE in the synaptic basal lamina. We have analyzed the time-course of acetylcholinesterase and acetylcholine receptors (AChR) mRNAs during mouse muscle cell differentiation in culture. In parallel, we have visualized the formation of AChE and AChR aggregates. We show that AChR clusters form first which correlates with high gamma-subunit mRNA levels. Then, AChE clusters appear with the onset of contraction and correlate with a dramatic increase in AChE, ColQ1 and ColQ1A mRNA levels in muscle cells. At that stage, AChR gamma-subunit levels drop while the expression level of epsilon-subunits increase. AChE aggregates are organized by a ternary complex, which involves direct interactions between ColQ, perlecan and MuSK.

Mitotic instability in wheat x Thinopyrum ponticum derivatives revealed by chromosome counting, nuclear DNA content and histone H3 phosphorylation pattern

To evaluate the mitotic stability of Triticum aestivum x Thinopyrum ponticum derivatives (BC(2)F(7) and BC(2)F(5) doubled haploids), chromosome counting by both conventional and immunostaining techniques, and measurement of DNA content were performed. The wheat progenitor line, PF 839197, the wheat recurrent parent CEP 19 and the control Chinese Spring were also investigated. In the hybrid derivatives, chromosome number ranged from 2n=36 to 60, with a predominance of chromosome numbers higher than 2n=42, that was confirmed by determination of nuclear DNA content. Chinese Spring' and PF 839197 were stable, but CEP 19 showed chromosome number variation (20%). Analyses of non-pretreated cells revealed the presence of anaphase bridges, lagging chromatids, chromosome fragments and micronuclei. Immunostaining with an antibody recognizing histone H3 phosphorylated showed dicentric chromatids forming anaphase bridges and pericentromeric phosphorylation at centric chromosome fragments but not at lagging chromatids. The possible causes of the observed mitotic instability are discussed.

The relationships among lemons, limes and citron: a chromosomal comparison

Lemons, limes and citron constitute a group of closely related Citrus species, whose species delimitations and taxonomic relationships are unclear. In order to identify karyotypic similarities and species relationships within this group, the CMA+/DAPI- banding pattern and the distribution of the 5S and 45S rDNA sites of 10 accessions of lime, lemon, and citron were investigated. The four cultivars of C. limon analyzed showed the same pattern of CMA+ bands and rDNA sites, suggesting that they originated from a single germplasm, later differentiated by distinct somatic mutations. The lemons C. jambhiri, C. limonia and C. volkameriana displayed karyotypes very similar to each other, but they differed from C. limon by the absence of a single chromosome with one band in each telomere. The limes, C. aurantifolia and C. limettioides, seemed less related to each other and exhibited different heteromorphic chromosome pairs. In C. aurantifolia, the presence of a chromosome type unknown in all other Citrus species cytologically known so far supports the assumption that this accession may be derived from a hybrid with a species from the subgenus Papeda or from another genus. Citrus medica was the only homozygous accession of this group and all of its chromosome types were clearly represented in limes and lemons, some of them forming heteromorphic pairs. The analysis of the distribution of rDNA sites allowed a further refinement of the comparison among accessions. The lemons and limes were heterozygous for all rDNA sites, whereas C. medica was entirely homozygous. These data support the hypothesis that C. medica is a true species while the other nine accessions are hybrids.

[Intracellular pH changes induced by sclerosing agents in peritoneal fibroblasts]

Sclerosing encapsulating peritonitis secondary to peritoneal dialysis has been associated to acetate-containing dialysis fluids, hypertonic glucose and disinfectants. Physiopathologic mechanisms of fibrotic proliferation that implicate those agents are not totally explained. With an experimental approach using cultured peritoneal fibroblasts, we have studied intracellular pH changes and Na+/H+ antiporter activity under cells perfusion with peritoneal dialysis liquids containing acetate, lactate, hypertonic glucose and interleukin-1. All experiments were performed at extracellular pH 7.4 and physiologic HCO3/CO2 concentration.

RESULTS

35 mM acetate produced a huge intracellular acidosis (ipH = 6.80 +/- 0.08). Lactate effect was less important (6.95 +/- 0.07), with a slow ipH recovery in about 30 min in both cases. IL-1, 10(-6) M also reduced ipH to 7.10 +/- 0.03. Acidosis was linked to Ca2+ outflow via Ca/H exchange and was blocked with Cd 20 nM. Extracellular Na = 0 and amiloride totally inhibited ipH recovery after acetate, lactate, or interleukin-induced acidosis. Hypertonic glucose perfusion increased ipH (7.31 +/- 0.06) for 5-7 min. This increase was also inhibited by amiloride or extracellular Na absence. Na+/H+ exchanger activity increased to 58%, and kept activated after ipH recovery. In conclusion, acetate, hypertonic glucose and IL-1 showed the common effect of stimulating the sodium-proton exchanger by different mechanisms, giving a possibility of potentiation. Activated Na+/H+ exchanger may act as a signal-transduction increasing fibroblast proliferation and explaining the cellular mechanism of sclerosing peritonitis.

Leiomyosarcoma of the popliteal artery: case report and review of the literature

Vascular leiomyosarcomas are rare tumors, and only 21 have been described as developing in the systemic arteries. We present a case, the sixth in the literature, of a leiomyosarcoma originating in the popliteal artery of a 67-year-old woman treated with en bloc excision of the neoplasia and the artery followed by a popliteal tibioperoneal trunk bypass. The patient then was underwent adjuvant radiotherapy and chemotherapy. After 31 months of follow-up, the patient has mild claudication but does not have either recurrence or metastasis.

Prosthetic replacement of the inferior vena cava and the iliofemoral vein for urologically related malignancies

OBJECTIVE

To evaluate the feasibility and results of prosthetic venous replacement, as inferior vena cava (IVC) and iliofemoral vein resection and replacement are sometimes necessary when they are extensively involved by a large and fixed tumour thrombus from renal cell carcinoma (RCC) or other urological malignancies.

PATIENTS AND METHODS

Five men and two women (age range 41-75 years) were treated over a 10-year period (1991-2001) by aggressive venous surgery to achieve complete tumour resection, with prosthetic graft replacement to re-establish venous flow. The tumours included RCC of the right kidney (two), retroperitoneal liposarcoma (two), bladder cancer (one), retroperitoneal fibrosarcoma (one) and inguino-pelvic lymphoma (one). Two patients had a vena caval replacement, of whom one had a circular reinforced PTFE and one a Dacron silver graft; five patients had either an iliofemoral or an ilio-iliac circular reinforced PTFE graft. The prosthetic diameter was 18-20 mm for the IVC grafts and 8-10 mm for the iliac grafts. In all the patients, graft patency was evaluated during the follow-up by colour flow duplex imaging, and in one it was determined by angio-computed tomography scan and venography.

RESULTS

One patient died 30 days after surgery; of the remaining six patients one had no evidence of regional recurrence or metastatic disease at 12 months, and five died from recurrent tumour 8-30 months after surgery. The mean time to death was 23 months. At 3 months all six prosthesis were patent; at 6 months four were patent and at 12 months three of five prostheses were patent.

CONCLUSION

Resecting and replacing the IVC allows complete tumour resection and avoids renal failure, providing durable relief from the symptoms of venous obstruction. Iliofemoral prosthetic reconstruction for urological-related malignancies represents a viable option to avoid venous engorgement and lower extremity swelling, at least in the early postoperative period. The mean time to death for the present patients must be considered the limit for these aggressive operations.