The meaning of DAPI bands observed after C-banding and FISH procedures

Under specific technical conditions chromosome staining with 4',6-diamidino-2-phenylindole (DAPI) permits characterization of heterochromatic regions as AT-rich (DAPI(+)) or AT-poor (DAPI(-)), especially when the chromosomes are counterstained with chromomycin A(3) (CMA), which preferentially binds to GC-rich DNA. DAPI(+) bands also often have been observed after C-banding or FISH. In these cases, however, it is not clear whether only AT-rich regions stain positively with DAPI or other heterochromatins with different base compositions also are stained. We evaluated the meaning of DAPI bands observed after C-banding and FISH using three plant species bearing different types of heterochromatin: DAPI(+)/CMA(-), DAP(-)/CMA(+) and DAPI(0)/CMA(0) (neutral bands). Additional tests were performed using propidium iodide, a fluorochrome without preferential affinity for AT or GC. Our results indicate that AT-rich heterochromatin stains as DAPI(+) bands after C-banding or FISH, but other kinds of heterochromatin also may be stained by DAPI.

Summer Pruning: An Ecological Alternative to Postharvest Calcium Treatment to Improve Storability of High Quality Apple cv. ‘Reinette du Canada’

Two strategies, summer pruning and postharvest Ca treatment, were studied in apple (Malus domestica Borkh) cv. ‘Reinette du Canada’ in order to analyze its effect on the fruit quality during storage. Summer pruning and Ca treatment reduced external and internal bitter-pits; so after 180 days of storage, both treatments decreased external bitter-pit by 10.0% and 16.7%, respectively. Summer pruning influenced color, firmness, total soluble solids and titratable acidity (TA) of fruit during storage, whereas Ca treatment only affected firmness and TA. Fruit from pruned trees had significant lower K and Mg than those from unpruned trees and Ca treatment increased Ca content. Orchard management, by means of summer pruning, combined with Ca postharvest application would be useful to prevent losses due to bitter-pit during storage in commercial orchards. However, in organic orchards, summer pruning would be the ecological alternative to decrease bitter-pit incidence during storage in high quality apple cv. ‘Reinette du Canada’. K/Ca ratio, on the peel at harvest, turned out to be the best parameter to correlate with external and internal bitter-pits during storage; so this ratio would be useful to predict bitter-pit on long-term storage.

Free radicals and antioxidants in two oxidative-stress cell models exposed to ochratoxin A and amyloid β: unexpected results

Oxidative stress is reported to be closely related to pathogenetic mechanisms and plays a central role in several molecular toxicities. It seems reasonable to hypothesize that antioxidant molecules and/or free radical scavengers can protect from oxidative stress-induced damage by quenching free-radical reactions. Leontopodic acid (LA) is a fully substituted, hexaric acid derivative isolated from Leontopodium alpinum Cass., commonly known as ‘Edelweiss’ (Asteraceae family), and exhibits significant chemical antioxidant power. The present study was designed to evaluate LA’s capacity to counteract induced oxidative stress in two in vitro cell models: one exposed the LLC-PK1 cell line to ochratoxin A and the other exposed the differentiated SH-SY5Y cells to amyloid β. The effects of a 24 h pretreatment with LA on induced ROS (reactive oxygen species) production and cytotoxicity were evaluated in the two models. Surprisingly, the results showed that while LA decreased ROS production, it did not increase cell survival.

Neocentrics and holokinetics (holocentrics): chromosomes out of the centromeric rules

The centromere appears as a single constriction at mitotic metaphase in most eukaryotic chromosomes. Holokinetic chromosomes are the exception to this rule because they do not show any centromeric constrictions. Holokinetic chromosomes are usually forgotten in most reviews about centromeres, despite their presence in a number of animal and plant species. They are generally linked to very intriguing and unusual mechanisms of mitosis and meiosis. Holokinetic chromosomes differ from monocentric chromosomes not only in the extension of the kinetochore plate, but also in many other peculiar karyological features, which could be understood as the 'holokinetic syndrome' that is reviewed in detail. Together with holokinetic chromosomes we review neocentromeric activity, a similarly intriguing case of regions able to pull chromosomes towards the poles without showing the main components reported to be essential to centromeric function. A neocentromere is a chromosomal region different from the true centromere in structure, DNA sequence and location, but is able to lead chromosomes to the cell poles in special circumstances. Neocentromeres have been reported in plants and animals showing different features. Both in humans and Drosophila, neocentric activity appears in somatic cells with defective chromosomes lacking a functional centromere. In most cases in plants, neocentromeres appear in chromosomes which have normal centromeres, but are active only during meiosis. Because of examples such as spontaneous or induced neocentromeres and holokinetic chromosomes, it is becoming less surprising that different structures and DNA sequences of centromeres appear in evolution.

[Retinal racemose hemangioma (Wyburn-Mason syndrome)--a patient ten years follow-up: case report]

To describe the case of a patient who presents retinal racemose hemangioma (Wyburn-Mason syndrome) and his 10 years follow-up. Ten years after the disease diagnosis, the ophthalmologic exam had no changes, as well as the campimetry and the retinography. The long term prognosis is controversial. Some authors report ocular lesions stability and others report progressive visual loss.

Influence of Harvest Dates on Quality, Storage Capacity and Sensory Attributes of European Plum cv. Green Gage

The aim of this work was to determine storage capacity and changes in quality and consumer acceptance in plum harvested at different dates as well as to determine which instrumental parameters show good correlation with consumer acceptance and sensory properties. Both harvest date and storage time played a significant role in quality and sensory characteristics. Incidence of internal breakdown (IB) was significantly higher in fruit harvested last and increased significantly until the end of storage. Market life of ‘Green Gage’ plum varies from 20 days in fruit harvested on the last harvest date to 40 days in fruit harvested on earlier dates. When storage is needed, firmness, the best harvest index, should be higher than 42 N in order to extend market life and prevent IB damages in ‘Green Gage’ plums. However, fruit from early harvest dates has a lower consumer acceptance than fruit from late harvest dates (low TSS:TA). Thus, a minimum quality threshold based on TSS:TA (18.9) has been established over which consumer liking for European plums cv. Green Gage improves significantly. High linear regression between a* and TSS:TA would allow to use the a* color parameter as a nondestructive measurement to estimate consumer acceptance.

207 EFFECT OF LOCATION AND STAGE OF THE DOMINANT FOLLICLE ON OVULATION AND PREGNANCY RATES IN ALPACAS

Gestation in camelids occurs in the left horn regardless of whether ovulation has taken place in the left or right ovary, suggesting uterine embryo migration (Fernandez-Baca S et al. 1970 Biol. Reprod. 3, 243-251). On the other hand, we have previously documented (Ratto MH et al. 2003 Theriogenology 60, 1645-1656) that more than 90% of llamas with the presence of a follicle ≥6 to 7 mm in diameter, regardless of their stage of development, did accept the copula and ovulate after mating. However, it is unknown whether these oocytes are competent to achieving acceptable pregnancy rate. This study was designed to determine the effect of location of the preovulatory dominant follicle (right or left ovary) on ovulation and pregnancy rates and to evaluate the effect of stage of ovarian follicle development at mating (growing, maintenance, and regression) on ovulation rate and embryo survival in alpacas. In Experiment 1, nonlactating alpacas (4-6 years of age) weighing 55 to 75 kg were randomly assigned to 1 of 2 groups according to the location of the dominant follicle detected by ultrasonography: right ovary [right dominant follicle (RDF); n = 96] or left ovary [left dominant follicle (LDF); n = 108]. Ovulation and pregnancy diagnoses were assessed by ultrasonography on Days 2 (Day 0 = mating) and 30, respectively. Ovulation was defined as the sudden disappearance of a large follicle (≥6 mm) that was detected during the ultrasonographic examination 24 to 36 h after mating. Ovulation rates (96.5 and 96.3% for RDF and LDF, respectively) and pregnancy rates (60.2 and 56.7% for RDF and LDF, respectively) rates did not differ (P = 0.9) among groups. In Experiment 2, nonlactating alpacas (4-8 years of age) weighing 60 to 80 kg (n = 4116) were submitted to ultrasound-guided follicle ablation to synchronize follicular wave emergence and, after daily ultrasonography examination, were randomly assigned to the following groups according to the growth phase and diameter of the dominant follicle: early growing (G1; 5-6 mm, n = 27), mid-growing (G2; 7-12 mm, n = 30); static (G3; 7-12 mm, n = 430), or regressing (G4; 12-7 mm, n = 29). All alpacas were mated with a proven male, except 5 alpacas from G1 that rejected the sire. The ovarian response was determined by ultrasound examinations that were carried out on Day 2 (ovulation rate), Day 9 (CL size), and Day 35 (presence of embryonic vesicle or embryo). Ovulation was determined as described in Experiment 1. No differences were detected in ovulation rate among groups (95, 96, 100, and 96%, respectively; P = 0.8) or in CL size (10.3 ± 0.8; 11.7 ± 0.6; 11.1 ± 0.8; and 11.1 ± 0.9 mm, respectively; P = 0.6). Pregnancy rate was highest in G2 (65.5%), intermediate in G1 (52.4%) and G3 (53.3%), and lowest in G4 (42.9%; P < 0.05). Results suggest that location of the dominant follicle has no influence on ovulation and pregnancy rates and that although mating during the regressing phase of the dominant follicle has no effect on ovulation, pregnancy rate may be compromised. This study was supported by DID-UACH, Universidad Austral de Chile.

Different chromatin fractions of tomato (Solanum lycopersicum L.) and related species

Conventional chromosome staining has suggested that more than 75% of the tomato chromosomes are constituted by heterochromatin. In order to determine whether more deeply stained proximal regions are classic heterochromatin, the distributions of C-bands and chromomycin A(3) (CMA) bands, and the prophase condensation patterns, were analysed in tomato. In this and most other species of the tomato clade, the 5S and 45S rDNA sites were also localised. In tomato, CMA banding was similar to C-banding. After conventional staining, all species displayed large condensed heteropycnotic regions that did not correspond to C-bands or CMA bands. Analyses of the CMA banded karyotypes revealed a low heterochromatin content. Around 12-17% of the chromatin of tomato was CMA(+) and 1/4 to 1/5 of this heterochromatin corresponded to 45S rDNA. In other species, the CMA(+) heterochromatin showed extensive variation (8-35%), but was never near the values found in the literature for tomato. These data suggest the existence of three principal fractions of chromatin in tomato and related species: the late condensed euchromatin corresponding to the terminal regions of the chromosomes, the precocious condensed euchromatin that occupies the major part of the chromosomes and the constitutive heterochromatin that represents those regions revealed by C-bands.

Ki67 as a prognostic biomarker for patients with vertical growth phase (VGP) melanomas

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Background: In VGP melanomas proliferation is reflected in dermal mitotic figures (“mitogenic” VGP) and/or tumor cell nests larger than any epidermal nest. An alternative to mitotic rate (MR) to characterize cell proliferation is the expression of Ki67 protein. Since Ki67 is expressed in all phases of the cell cycle except G0, it is potentially a more robust biomarker for proliferation and prognosis than mitoses. Methods: To test the hypothesis that Ki67 would replace MR as a prognostic factor, we did a retrospective cohort study of 432 patients with Stage I/II primary VGP melanomas who had at least 10 years of follow up. Tissue sections were stained using the monoclonal antibody MIB-1 to Ki67 and the % of positive melanoma cells were evaluated by two readers. ROC curves for Ki67 and MR were computed. Predicted probabilities (PP) of 10-year melanoma-specific death were computed from 3 multivariate logistic regression models, one for each biomarker (Models 1 and 2) and one with both (Model 3), controlling for established melanoma prognostic factors (thickness, gender, anatomic site, ulceration, regression and tumor infiltrating lymphocytes), and compared. Cross-validation was used to assess differences between using Ki67 and using MR including the differences in PP, Brier scores and the misclassification rates. A decision curve analysis was done to assess the clinical net benefit of the two. Results: The areas under the ROC curve (AUCs) for Ki67 and MR, both continuous factors, were 0.69 and 0.79, respectively. In the multivariate analysis, Ki67 expression was significant in Model 1 (OR=1.03, 95% CI: 1.01–1.05), mitotic rate was not significant in Model 2 (1.05, 0.99–1.1), and only Ki67 was significant in Model 3 (1.03, 1.01–1.05). The AUCs for the three models were 0.84, 0.84, and 0.85, respectively. Based on cross-validation, there was no difference between the two biomarkers in PP, Brier scores, or misclassification rates. The decision cost analysis demonstrated the same net benefit for the two. Conclusions: A prospective study needs to be conducted to confirm that Ki67 and MR are equivalent.

No significant financial relationships to disclose.

Prognostic factors in relapsed or refractory male germ cell tumors: Results from an international study of 1,593 patients

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Background: The results of salvage treatment in male patients (pts) with relapsed or refractory germ-cell tumors (rr-GCT) depend considerably on prognostic factors. However, individual factors are not broadly accepted. Methods: Between 09/2007 and 12/2008 data on 1984 pts with rr-GCT were collected from 38 centers/groups worldwide. Inclusion criteria were (1) First line treatment for metastatic GCT after January 1, 1990; (2) Cisplatin and etoposide as part of first-line regimens; (3) No first-line high-dose chemotherapy (HDCT); (4) Relapse or progression after first-line treatment; (5) Cisplatin- based conventional-dose regimens or HDCT as salvage treatment. Data were centrally reviewed and checked for consistency. The primary endpoint was progression-free survival (PFS). Prognostic factors were identified using Cox multivariate regression analysis. Results: Overall 1593 (80%) pts fulfilled the strict inclusion criteria. Salvage treatment given as consolidation of first-line treatment in patients without progression was the most frequent cause of exclusion. Median follow-up was 58 months (range 1 to 206 months). Three-year PFS for the entire group was 38% (95% CI: 35%-40%), the overall survival was 51% (95% CI: 48%-54%). Multivariate analysis on a randomly selected 2/3 training dataset identified the following variables as the most significant ones for PFS: see Table . Cisplatin-refractory or absolute refractory disease was a confounding factor for response to first-line treatment. Conclusions: This preliminary analysis of a large dataset allowed the identification of important prognostic factors in rr- GCT. A prognostic score for first-salvage treatment based on the results of a final analysis will be presented.

[Table: see text]

No significant financial relationships to disclose.

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.