Double-pulsed wave packets in spontaneous radiation from a tandem undulator.

We verify that each wave packet of spontaneous radiation from two undulators placed in series has a double-pulsed temporal profile with pulse spacing which can be controlled at the attosecond level. Using a Mach-Zehnder interferometer operating at ultraviolet wavelengths, we obtain the autocorrelation trace for the spontaneous radiation from the tandem undulator. The results clearly show that the wave packet has a double-pulsed structure, consisting of a pair of 10-cycle oscillations with a variable separation. We also report the characterization of the time delay between the double-pulsed components in different wavelength regimes. The excellent agreement between the independent measurements confirms that a tandem undulator can be used to produce double-pulsed wave packets at arbitrary wavelength.

FGF2/EGF contributes to brain neuroepithelial precursor proliferation and neurogenesis in rat embryos: the involvement of embryonic cerebrospinal fluid.

BACKGROUND: At the earliest stages of brain development, the neuroepithelium works as an interdependent functional entity together with cerebrospinal fluid, which plays a key regulatory role in neuroepithelial cell survival, replication and neurogenesis; however, the underlying mechanism remains unknown in mammals. RESULTS: We show the presence of fibroblast growth factor 2 (FGF2) and epidermal growth factor (EGF), in 13.5-day rat embryo cerebrospinal fluid (eCSF). Immunohistochemical detection of FGF2 expression localized this factor inside neuroepithelial precursors close to the neuroepithelial-CSF interface, suggesting that FGF2 from eCSF could originate in the neuroepithelium by apical secretion. The colocalization of FGFR1 and FGF2 in some neuroepithelial cells close to the ventricular surface suggests they are target cells for eCSF FGF2. Brain neuroepithelium EGF expression was negative. By using a neuroepithelial organotypic culture, we demonstrate that FGF2 and EGF from eCSF plays a specific role in triggering the self-renewal and are involved in neurogenetic induction of mesencephalic neuroepithelial precursor cells during rat development. CONCLUSIONS: We propose eCSF as an intercommunication medium for neuroepithelial precursor behavior control during early rat brain development, and the neuroepithelial regulation of FGF2 and EGF presence in eCSF, as a regulative mechanism controlling precursor proliferation and neurogenesis.

17α-Ethinylestradiol and 17ß-estradiol removal from a secondary urban wastewater using an RBC treatment system.

The presence of micropollutants that include endocrine-disrupting compounds (EDC) in aquatic environments is currently one of the most relevant aspects of water quality due to their adverse effects on aquatic organisms and human health. From the several categories of EDC, 17ß-estradiol (E2) is a natural hormone, which is prevalent in vertebrates, associated with the female reproductive system and maintenance of the sexual characters. 17α-Ethinylestradiol (EE2) is a synthetic hormone produced from the natural hormone E2 and is an essential component of oral contraceptives. These compounds are susceptible to bioconcentration and have high potential to bioaccumulation. Wastewater treatment plants are the main point source of E2 and EE2 into aquatic environments, but conventional wastewater treatment systems are not specifically designed for steroid removal. To overcome this problem, biological tertiary treatment may be a solution for the removal of emergent pollutants such as E2 and EE2. The main purpose of the present study is to provide a solution based on the optimization of a rotating biological contactor system to remove estrogens, specifically E2 and EE2, and to quantify their removal efficiency on different matrices, namely real wastewater and different synthetic wastewaters. All assays presented viable removal efficiencies for compound E2 with values always above 50%; real wastewater yielded the highest removal efficiencies. EE2 removal had better removal efficiencies with synthetic wastewater as feed solution, with removals above 15%, whereas the removal efficiency with real wastewater was inexistent.

Embryonic cerebrospinal fluid activates neurogenesis of neural precursors within the subventricular zone of the adult mouse brain.

INTRODUCTION: There is a nondeveloped neurogenic potential in the adult mammalian brain, which could be the basis for neuroregenerative strategies. Many research efforts have been made to understand the control mechanisms which regulate the transition from a neural precursor to a neuron in the adult brain. Embryonic cerebrospinal fluid (CSF) is a complex fluid which has been shown to play a key role in neural precursor behavior during development, working as a powerful neurogenic inductor. We tested if the neurogenic properties of embryonic CSF are able to increase the neurogenic activity of neuronal precursors from the subventricular zone (SVZ) in the brains of adult mice. RESULTS: Our results show that mouse embryonic CSF significantly increases the neurogenic activity in precursor cells from adult brain SVZ. This intense neurogenic effect was specific for embryonic CSF and was not induced by adult CSF. CONCLUSIONS: Embryonic CSF is a powerful neurogenesis inductor in homologous neuronal precursors in the adult brain. This property of embryonic CSF could be a useful tool in neuroregeneration strategies.

Reversible myocardial hypertrophy induced by tacrolimus in a pediatric heart transplant recipient: case report.

Tacrolimus is a potent immunosuppressant that is frequently used in organ transplantation. However, adverse effects include cardiac toxicity. Herein we describe transient myocardial hypertrophy induced by tacrolimus after heart transplantation. The hypertrophy caused no clinical symptoms but was noted because of elevation of plasma brain natriuretic peptide concentration and confirmed at echocardiography. Initially, allograft rejection was feared; however, myocardial biopsy samples revealed only interstitial edema and mild myocardial hypertrophy; neither cellular nor humoral rejection was detected. The blood tacrolimus concentration was higher than usual at that time; thus, tacrolimus dosage was reduced. Myocardial hypertrophy completely resolved upon reducing the target concentration of tacrolimus and did not recur, as confirmed at echocardiography and myocardial biopsy. Thus, we conclude that tacrolimus induces reversible myocardial hypertrophy. In patients receiving tacrolimus therapy, blood concentration should be carefully controlled and extreme attention paid to cardiac involvement.

Early embryonic brain development in rats requires the trophic influence of cerebrospinal fluid.

Cerebrospinal fluid has shown itself to be an essential brain component during development. This is particularly evident at the earliest stages of development where a lot of research, performed mainly in chick embryos, supports the evidence that cerebrospinal fluid is involved in different mechanisms controlling brain growth and morphogenesis, by exerting a trophic effect on neuroepithelial precursor cells (NPC) involved in controlling the behaviour of these cells. Despite it being known that cerebrospinal fluid in mammals is directly involved in corticogenesis at fetal stages, the influence of cerebrospinal fluid on the activity of NPC at the earliest stages of brain development has not been demonstrated. Here, using "in vitro" organotypic cultures of rat embryo brain neuroepithelium in order to expose NPC to or deprive them of cerebrospinal fluid, we show that the neuroepithelium needs the trophic influence of cerebrospinal fluid to undergo normal rates of cell survival, replication and neurogenesis, suggesting that NPC are not self-sufficient to induce their normal activity. This data shows that cerebrospinal fluid is an essential component in chick and rat early brain development, suggesting that its influence could be constant in higher vertebrates.

Chondroitin sulphate-mediated fusion of brain neural folds in rat embryos.

Previous studies have demonstrated that during neural fold fusion in different species, an apical extracellular material rich in glycoconjugates is involved. However, the composition and the biological role of this material remain undetermined. In this paper, we show that this extracellular matrix in rat increases notably prior to contact between the neural folds, suggesting the dynamic behaviour of the secretory process. Immunostaining has allowed us to demonstrate that this extracellular matrix contains chondroitin sulphate proteoglycan (CSPG), with a spatio-temporal distribution pattern, suggesting a direct relationship with the process of adhesion. The degree of CSPG involvement in cephalic neural fold fusion in rat embryos was determined by treatment with specific glycosidases.In vitro rat embryo culture and microinjection techniques were employed to carry out selective digestion, with chondroitinase AC, of the CSPG on the apical surface of the neural folds; this was done immediately prior to the bonding of the cephalic neural folds. In all the treated embryos, cephalic defects of neural fold fusion could be detected. These results show that CSPG plays an important role in the fusion of the cephalic neural folds in rat embryos, which implies that this proteoglycan could be involved in cellular recognition and adhesion.

Prenatal expression of interleukin 1beta and interleukin 6 in the rat pituitary gland.

It is known that interleukin 1beta (IL-1beta) and interleukin 6 (IL-6) are expressed post-natally in normal and tumoral cells in the anterior pituitary, and that they play a role in both the liberation of different hormones and in the growth, proliferation and tumor formation of the pituitary gland. However, their expression and role during embryonic and fetal development remain unknown. We have performed an immunocytochemistry study of prenatal expression and distribution of IL-1beta and IL-6 in isolated embryonic rat Rathke's pouch prior to birth, more specifically between 13.5 and 19.5 days p.c. Western-blot analysis carried out on 19.5-day p.c. embryos showed positive immunolabelling for IL-1beta and IL-6. These interleukins were initially expressed simultaneously in the rostral and ventral portions of Rathke's pouch in 15.5-day p.c. embryos, and this expression progressed caudodorsally in later developmental stages, extending to most of the hypophysis before birth. The number of cells expressing these interleukins increased throughout this period: 48.22% of anterior pituitary cells expressed IL-6 in 19.5-day embryos, whilst IL-1beta was positive in 39.8% of the cells. Moreover, we have demonstrated that some adenohypophyseal cells co-express both interleukins. Such findings represent the first step towards an understanding of the physiological role of these interleukins in anterior pituitary development.

Which factors predict the recovery of natural heart function after insertion of a left ventricular assist system?

BACKGROUND: Recent reports have demonstrated that use of a left ventricular assist system (LVAS) can initiate recovery of cardiac function, and subsequent weaning from the LVAS has attracted considerable interest. In this study we investigated reliable predictors of LVAS weaning. METHODS: Eighty-two patients underwent LVAS implantation between April 1994 and July 2006 at our institution. Cardiac function was restored in 8 patients, who were weaned from LVAS after a mean of 5 months (Group R). Thirty-three patients remained on LVAS support for >1 year (Group N) because natural heart function did not show adequate improvement. We retrospectively evaluated the differences between these two groups. Group R was younger, and had a shorter duration of heart failure than Group N (23.4 vs 36.7 years and 13.3 vs 56.1 months, p < 0.01, respectively). Pathologic findings showed that the interstitial fibrosis score was lower in Group R (p < 0.01). Three months after LVAS insertion, B-type natriuretic peptide (BNP) and fractional shortening (FS) were more favorable (66.6 +/- 46 vs 264.5 +/- 170 pg/ml, p < 0.01, and 23 +/- 17.1 vs 12 +/- 9.1%, p < 0.05, respectively) in Group R. Furthermore, Group R received a higher dose of beta-blocker (15.4 +/- 8.4 vs 5.8 +/- 3.9 mg, p < 0.05). CONCLUSIONS: Younger age, shorter history of heart failure, and less interstitial fibrosis were effective predictors of weaning from LVAS. Restoration of natural heart function was more rapid and more persistent in candidates for LVAS explantation, and presence of beta-blocker played a prominent role in improving cardiac function after LVAS implantation.

Role of interleukin-1beta in the control of neuroepithelial proliferation and differentiation of the spinal cord during development.

Interleukin-1beta (IL-1beta) is an important trophic factor in the nervous system (NS). IL-1beta is ubiquitously expressed from very early stages during the development of the amphibian NS and its action has been demonstrated in vitro on survival, proliferation and differentiation in mammalian embryos. In this report, we show that IL-1beta is immunocytochemically expressed in embryonic spinal cord from early stages, both in rat (embryonic day 12) and in chicken (stage 17-HH), in neuroepithelial cells and nerve fibres, dorsal root ganglia, anterior and posterior roots of the spinal nerves, and in the fibres of these nerves. Our in vivo experiments on chick embryos, with microbeads impregnated with IL-1beta implanted laterally to the spinal cord at the level of the wing anlage, demonstrate that this cytokine produces a statistically significant increase in nuclear incorporation of BrdU at the dorsal level and a reduction of this at the ventral level, whereas local immunoblocking with anti-IL-1beta antibodies causes a dorsal reduction of BrdU incorporation and alters ventral differentiation. These data demonstrate that IL-1beta plays a part in controlling proliferation and early differentiation during the development of the spinal cord in chick embryos.

CA-125 AUC as a new prognostic factor for patients with ovarian cancer.

OBJECTIVE: The aim of the present study was to investigate the usefulness of the CA-125 area under the curve (AUC) as a new kinetic parameter for predicting overall survival in patients with ovarian cancer. In addition, the relationship of CA-125 AUC with other prognostic factors of ovarian cancer was evaluated. METHODS: Ninety-two patients that underwent primary line chemotherapy within 4 months after submission to cytoreductive surgery were included. For each patient, CA-125 AUC was calculated and a statistical analysis was conducted to compare CA-125 AUC behavior among patients according to several covariates. RESULTS: The mean age at diagnostic time was found to be 55.5 (16.1-82.4) years with a mean survival of 39.2 (3.5-100.1; SE = 2.6) months. Across FIGO stage I, II, III, and IV patients had a mean CA-125 AUC of 18.2, 24.6, 147.8, and 574.6 IU/ml*days, respectively (P < 0.05). At the evaluation date, living patients had a mean CA-125 AUC of 40.1 in contrast to 234.1 IU/ml*days (P < 0.05) for deceased ones. Patients with a complete response to primary chemotherapy had a mean CA-125 AUC of 48.8, while patients with a partial response had a mean of 251.7 IU/ml*days, and patients with no response or disease progression had a mean of 316.5 IU/ml*days (P < 0.05). The best CA-125 AUC performance is in predicting patient complete response to chemotherapy with a cut-off of 100 IU/ml*days and an accuracy of 82%. CONCLUSIONS: Despite CA-125 AUC high correlation with the FIGO stage, residual disease, and patient final outcome, the main interest of CA-125 AUC calculation is to evaluate the treatment efficacy and to foresee a full chemotherapy response. Further studies should be carried out before extrapolating these results to other data sets.

Embryonic cerebrospinal fluid regulates neuroepithelial survival, proliferation, and neurogenesis in chick embryos.

Early in development, the behavior of neuroepithelial cells is controlled by several factors, which act in a developmentally regulated manner. Diffusible factors are secreted locally by the neuroepithelium itself, although other nearby structures may also be involved. Evidence suggests a physiological role for the cerebrospinal fluid in the development of the brain. Here, using organotypic cultures of chick embryo neuroepithelial explants from the mesencephalon, we show that the neuroepithelium in vitro is not able to self-induce cell survival, replication, and neurogenesis. We also show that the embryonic cerebrospinal fluid (E-CSF) promotes neuroepithelial stem cell survival and induces proliferation and neurogenesis in mesencephalic explants. These data strongly suggest that E-CSF is involved in the regulation of neuroepithelial cells behavior, supporting the hypothesis that this fluid plays a key role during the early development of the central nervous system.

N-acetylcysteine prevents intra-acinar oxygen free radical production in pancreatic duct obstruction-induced acute pancreatitis.

Although oxygen free radicals (OFR) are considered to be one of the pathophysiological mechanisms involved in acute pancreatitis (AP), the contribution of acinar cells to their production is not well established. The aim of the present study was to determine the effect of N-acetylcysteine (NAC) in the course of AP induced by pancreatic duct obstruction (PDO) in rats, directly analysing by flow cytometry the quantity of OFR generated in acinar cells. NAC (50 mg/kg) was administered 1 h before and 1 h after PDO. Measurements by flow cytometry of OFR generated in acinar cells were taken at different PDO times over 24 h, using dihydrorhodamine-123 as fluorescent dye. Histological studies of pancreas and measurements of neutrophil infiltration in the pancreas, pancreatic glutathione (GSH), malondialdehyde (MDA) levels, plasma amylase activity and hemoconcentration were carried out in order to assess the severity of AP at different stages. NAC effectively blunted GSH depletion at early AP stages and prevented OFR generation found in acinar cells as a consequence of AP induced by PDO. This attenuation of the redox state impairment reduced cellular oxidative damage, as reflected by less severe pancreatic lesions, normal pancreatic MDA levels, as well as diminished neutrophil infiltration in pancreas. Hyperamylasemia and hemoconcentration following AP induction were ameliorated by NAC administration at early stages, when oxidative stress seems to be critical in the development of pancreatitis. In conclusion, NAC reinforces the antioxidant defences in acinar cells, preventing OFR generation therefore attenuating oxidative damage and subsequently reducing the severity of PDO-induced AP at early stages of the disease.

N-acetylcysteine induces beneficial changes in the acinar cell cycle progression in the course of acute pancreatitis.

Oxygen free radicals (OFR) are produced in the course of acute pancreatitis (AP). In addition to injurious oxidative effects, they are also involved in the regulation of cell growth. The aim of the present study was to examine the relationship between the effectiveness of N-acetyl-l-cysteine (NAC) to prevent the generation of OFR and the changes in the cell-cycle pattern of acinar cells in the course of AP induced in rats by pancreatic duct obstruction (PDO). NAC (50 mg/kg) was administered 1 h before and 1 h after PDO. Flow-cytometric measurement of OFR generation in acinar cells was carried out using dihydrorhodamine as fluorescent dye. Plasma amylase activity, pancreatic glutathione (GSH) content and TNF-alpha plasma levels were also measured. The distribution of acinar cells throughout the different cell-cycle phases was analysed at different AP stages by flow cytometry using propidium iodide staining. NAC administration reduced the depletion of pancreatic GSH content and prevented OFR generation in acinar cells of rats with PDO-induced acute pancreatitis. As a result, AP became less severe as reflected by the significant improvement of hyper-amylasaemia and maintenance of plasma TNF-alpha levels at values not significantly different from controls were found. NAC administration inhibited progression of cell-cycle phases, maintaining acinar cells in quiescent state at early PDO times. The protection from oxidative damage by NAC treatment during early AP, allows the pancreatic cell to enter S-phase actively at later stages, thereby allowing acinar cells to proliferate and preventing the pancreatic atrophy provoked by PDO-induced AP. The results provide evidence that OFR play a critical role in the progression of acinar cell-cycle phases. Prevention of OFR generation of acinar cells in rats with PDO-induced AP through NAC treatment, not only protects pancreas from oxidative damage but also promotes beneficial changes in the cell cycle progression which reduce the risk of pancreatic atrophy.

Major pathological mechanisms of acute pancreatitis are prevented by N-acetylcysteine.

AIM: To analyze the capability of N-acetylcysteine (NAC) to prevent major intra-acinar pathogenic mechanisms involved in the development of acute pancreatitis (AP). METHODS: AP was induced by pancreatic duct obstruction (PDO) in rats. Some animals received NAC (50 mg/kg) 1 h before and 1 h after PDO. During a 24-hour period of PDO, plasma amylase activity and pancreatic glutathione and malondialdehyde levels were measured. Cytosolic Ca(2+) levels and enzyme (amylase and trypsinogen) load in acinar cells were also analyzed by flow cytometry, and histological analysis of the pancreas was performed by electron microscopy. RESULTS: NAC avoided glutathione depletion at early AP stages, thereby preventing pancreatic oxidative damage, as reflected by normal malondialdehyde levels. By limiting oxidative stress, NAC treatment effectively prevented the impairment of Ca(2+) homeostasis found in acinar cells from early AP onwards, thus protecting the pancreas from damage. In addition, lower quantities of digestive enzymes were accumulated within acinar cells. This finding, together with the significantly lower hyperamylasemia observed in these animals, suggests that NAC treatment palliates the exocytosis blockade induced by PDO. CONCLUSION: By preventing oxidative stress at early AP stages, NAC administration prevents other pathological mechanisms of AP from being developed inside acinar cells, thus palliating the severity of disease.

Nitrite removal in a submerged biofilter.

Nowadays submerged filters seem to be the preferred technology for denitrification purposes. Optimisation of biological nitrogen has recently been tried based the nitrate shunt in order to save two of the involved steps. Former studies have shown that a build-up of nitrite can be achieved by an appropriate control of the nitrification process either in suspended cultures or in fixed cultures. An experimental plan was conducted to study the effect of different types of carbon source (acetate, ethanol and urban wastewater) on the performance of a submerged down flow biofilter, as well as the influence of the hydraulic loading. Results have shown that maximum nitrogen removal rates were similar for acetate and ethanol attaining values significantly higher than for urban waste water. On the other hand, nitrogen massic loading appeared to be the limiting factor for efficiency rather than hydraulic loading.

The intramedullary elongation nail for femoral lengthening.

We have analysed the results of 24 femoral lengthenings in 23 patients operated on between 1993 and 2000, using a gradual elongation intramedullary nail (Albizzia). Of the 23 patients, 22 had femoral deficiency and one was of short stature. Their mean age was 16.9 years. Technical difficulties encountered during the procedure were mild or moderate in 18 femora and severe in six femora. Distraction was obtained by 15 ratchetings per day (1 mm/day). There were 18 excellent results although in two patients this was achieved after the development of a pseudarthrosis which required further surgery. There were four good and two fair results in which the lengthening obtained was at least 3 cm less than had been projected. The consolidation index was 35.2 days/cm. No patient had associated long-term stiffness of the knee. Femoral lengthening using an elongation nail gives good results and is a comfortable procedure.

Time-course of oxygen free radical production in acinar cells during acute pancreatitis induced by pancreatic duct obstruction.

The time-course of oxygen free radicals (OFR) generation within acinar cells was studied at different stages of acute pancreatitis (AP) induced in rats by duct obstruction (PDO) for 48 h by flow cytometry, using dihydrorhodamine-123 (DHR) as fluorescent dye. Parallel measurements of the most common markers of oxidative stress such as glutathione (GSH) depletion and malondialdehyde (MDA) levels in pancreas were also performed. OFR production significantly increased within acinar cells at early stages of AP, concomitant with a marked depletion in pancreatic GSH. Lipid peroxidation was significantly enhanced 6 h after PDO, suggesting that the antioxidant defence system of the cell is overwhelmed by OFR production. Both MDA and OFR production in acinar cells decreased to normal values at late AP stages, thus allowing the recovery of pancreatic GSH levels 48 h after PDO. Among the two types of acinar cells differentiated by flow cytometry, R1 and R2, it was the R2 population that showed higher values of DHR dye. However, no differences between the two cell types were found regarding the amount of OFR generation. Our results demonstrate that individual acinar cells significantly contribute to produce large amounts of OFR at early stages of AP. The two existing populations of acinar cells displayed similar behaviour regarding oxidative stress over the course of the disease.

Important role of energy-dependent mitochondrial pathways in cultured rat cardiac myocyte apoptosis.

Recent studies have suggested that apoptosis and necrosis share common features in their signaling pathway and that apoptosis requires intracellular ATP for its mitochondrial/apoptotic protease-activating factor-1 suicide cascade. The present study was, therefore, designed to examine the role of intracellular energy levels in determining the form of cell death in cardiac myocytes. Neonatal rat cardiac myocytes were first incubated for 1 h in glucose-free medium containing oligomycin to achieve metabolic inhibition. The cells were then incubated for another 4 h in similar medium containing staurosporine and graded concentrations of glucose to manipulate intracellular ATP levels. Under ATP-depleting conditions, the cell death caused by staurosporine was primarily necrotic, as determined by creatine kinase release and nuclear staining with ethidium homodimer-1. However, under ATP-replenishing conditions, staurosporine increased the percentage of apoptotic cells, as determined by nuclear morphology and DNA fragmentation. Caspase-3 activation by staurosporine was also ATP dependent. However, loss of mitochondrial transmembrane potential (DeltaPsi(m)), Bax translocation, and cytochrome c release were observed in both apoptotic and necrotic cells. Moreover, cyclosporin A, an inhibitor of mitochondrial permeability transition, attenuated staurosporine-induced apoptosis and necrosis through the inhibition of DeltaPsi(m) reduction, cytochrome c release, and caspase-3 activation. Our data therefore suggest that staurosporine induces cell demise through a mitochondrial death signaling pathway and that the presence of intracellular ATP favors a shift from necrosis to apoptosis through caspase activation.