Moments of the longitudinal proton structure function FL from global data in the Q(2) range 0.75-45.0 (GeV/c)(2).

We present an extraction of the lowest three moments of the proton longitudinal structure function FL from world data between Q(2)=0.75 and 45 (GeV/c)(2). The availability of new FL data at low Bjorken x from HERA and at large x from Jefferson Lab allows the first determination of these moments over a large Q(2) range, relatively free from uncertainties associated with extrapolations into unmeasured regions. The moments are found to be underestimated by leading twist structure function parametrizations, especially for the higher moments, suggesting either the presence of significant higher twist effects in FL and/or a larger gluon distribution at high x.

Robotic radical parametrectomy with pelvic lymphadenectomy: our experience and review of the literature.

AIMS: To evaluate the feasibility and safety of robotic radical parametrectomy (RRP) and pelvic lymphadenectomy for the management of occult invasive cervical cancer or local recurrence of endometrial cancer and to compare our outcomes with the evidence available in the literature. METHODS: Starting from 07/2008 consecutive patients submitted to RRP have been included in this study. A comprehensive literature review of published papers about this subject was carried out. RESULTS: During the study period 11 patients were managed; 7 and 4 patients had an occult cervical cancer and a vaginal recurrence of endometrial cancer, respectively. One intra-operative and one post-operative complications were recorded. Neither conversion to laparotomy, nor blood transfusions occurred. Three women required further adjuvant therapies. After a median follow-up of 19 months (range 8-36) one recurrence has been detected. The outcomes of other 200 women from 15 different papers have been collected and compared to our findings. CONCLUSIONS: Robotic surgery represents an effective alternative to accomplish radical parametrectomy with comparable results of those reported in the literature in terms of feasibility and safety. RRP is certainly a demanding procedure which however avoids radiotherapy in more than 80% of cases.

[Risk assessment: use of the SOBANE model at the Health Authority of Lodi province]. / La valutazione del rischio: applicazione del modello SOBANE nell'ASL di Lodi.

The evaluation of the risks for the health safeguard within the workplace, represents a fundamental moment of the intervention planning. During the years it has been enriched by experiences, improvements and techniques essentially introduced by a set of laws; in particular the 626/94 Legislative Decree. This was the first well-organized expression of the new strategies identified on the basis of the assigned responsibilities and the protection of the production process. With the 81/08 L.D. such strategies have been once again highlighted but with a particular emphasis on the partecipation of the workers in the risk detection. This work just deals with such aspect by means of the experimentation of a specific method represented by the so called SOBANE pattern. The results point out some aspects that are positive in terms of satisfaction and handiness. These aspects may contribute to the employment of the method to a wide range of services with important effects on the drawing up of the evaluation document of the business risks

Gynecological fertility-sparing surgery.

The implementation of early detection protocols and advanced treatment strategies has significantly improved survival outcomes for gynecologic cancer patients. The improvement of oncological outcomes has led to an increased attention toward Quality of Life issues, including the childbearing potential for young women. Traditionally the surgical treatment of cervical, endometrial and ovarian cancers involves the removal of the uterus and adnexa, irrespective of the impact on fertility and parenthood and regardless of patient desires. For young women affected by gynecological malignancies at an apparently early stage, fertility-sparing procedures could be offered. The aim of our review is to going through the available evidence in the Literature and to evaluate the current state of art regarding fertility-sparing procedures for women with gynecological malignancies in terms of oncological and fertility outcomes.

Nonadiabatic quantum dynamics and laser control of Br2 in solid argon.

A five-dimensional reaction surface-vibronic coupling model is introduced to describe the B- to C-state predissociation dynamics of Br(2) occupying a double substitutional lattice site in a face-centered cubic argon crystal at low temperatures. The quantum dynamics driven by a Franck-Condon vertical excitation is investigated, revealing the role of matrix cage compression for efficient nonadiabatic transitions. Vibrational preexcitation of the Br(2) bond in the electronic ground state can be used to access a different regime of predissociation which does not require substantial matrix compression because the Franck-Condon window shifts into the energetic range of the B-C level crossing. Using optimal control theory, it is shown how vibrational preexcitation can be achieved via a pump-dump-type mechanism involving the repulsive C state.

Drastic reduction of the slow gate of human muscle chloride channel (ClC-1) by mutation C277S.

1. Single channel measurements suggest that the human muscle chloride channel ClC-1 presumably has a double barrelled structure, with a fast single protopore gate and a slow common pore gate similar to that of ClC-0, the chloride channel from Torpedo. The single point mutation C212S has been shown to abolish the slow gating of ClC-0 locking the slow gate in the open state. In order to test the hypothesis that the slow gating process found in ClC-1 corresponds to the well characterised slow gate found in ClC-0 we investigated the gating effects in ClC-1 of the homologous mutation corresponding to C212S, C277S. 2. We found that the mutation C277S strongly reduced the slow component of macroscopic gating relaxations at negative and at positive voltages. 3. Time constants of the fast gating relaxations were not affected by the mutation but the minimal open probability of the fast gate at negative voltages was slightly reduced to 0.08 compared with the WT value of 0.22. 4. Additionally, we characterised the block of WT ClC-1 and mutant C277S by the S(-) enantiomer of CPB (2-(p-chlorophenoxy) butyric acid), and found that the block is practically unaffected by the mutation suggesting that CPB does not interact with the slow gate of ClC-1. 5. We conclude that the slow and fast gating processes of ClC-1, respectively, reflect the slow common pore gate and the single protopore gate of the double-barrelled ClC-1 channel.

Mechanism of block of single protopores of the Torpedo chloride channel ClC-0 by 2-(p-chlorophenoxy)butyric acid (CPB).

We investigated in detail the mechanism of inhibition by the S(-) enantiomer of 2-(p-chlorophenoxy)butyric acid (CPB) of the Torpedo Cl(-)channel, ClC-0. The substance has been previously shown to inhibit the homologous skeletal muscle channel, CLC-1. ClC-0 is a homodimer with probably two independently gated protopores that are conductive only if an additional common gate is open. As a simplification, we used a mutant of ClC-0 (C212S) that has the common gate "locked open" (Lin, Y.W., C.W. Lin, and T.Y. Chen. 1999. J. Gen. Physiol. 114:1-12). CPB inhibits C212S currents only when applied to the cytoplasmic side, and single-channel recordings at voltages (V) between -120 and -80 mV demonstrate that it acts independently on individual protopores by introducing a long-lived nonconductive state with no effect on the conductance and little effect on the lifetime of the open state. Steady-state macroscopic currents at -140 mV are half-inhibited by approximately 0.5 mM CPB, but the inhibition decreases with V and vanishes for V > or = 40 mV. Relaxations of CPB inhibition after voltage steps are seen in the current responses as an additional exponential component that is much slower than the gating of drug-free protopores. For V = 60 mV) with an IC50 of approximately 30-40 mM. Altogether, these findings support a model for the mechanism of CPB inhibition in which the drug competes with Cl(-) for binding to a site of the pore where it blocks permeation. CPB binds preferentially to closed channels, and thereby also strongly alters the gating of the single protopore. Since the affinity of CPB for open WT pores is extremely low, we cannot decide in this case if it acts also as an open pore blocker. However, the experiments with the mutant K519E strongly support this interpretation. CPB block may become a useful tool to study the pore of ClC channels. As a first application, our results provide additional evidence for a double-barreled structure of ClC-0 and ClC-1.

Fast and slow gating relaxations in the muscle chloride channel CLC-1.

Gating of the muscle chloride channel CLC-1 involves at least two processes evidenced by double-exponential current relaxations when stepping the voltage to negative values. However, there is little information about the gating of CLC-1 at positive voltages. Here, we analyzed macroscopic gating of CLC-1 over a large voltage range (from -160 to +200 mV). Activation was fast at positive voltages but could be easily followed using envelope protocols that employed a tail pulse to -140 mV after stepping the voltage to a certain test potential for increasing durations. Activation was biexponential, demonstrating the presence of two gating processes. Both time constants became exponentially faster at positive voltages. A similar voltage dependence was also seen for the fast gate time constant of CLC-0. The voltage dependence of the time constant of the fast process of CLC-1, tau(f), was steeper than that of the slow one, tau(s) (apparent activation valences were z(f) approximately -0. 79 and z(s) approximately -0.42) such that at +200 mV the two processes became kinetically distinct by almost two orders of magnitude (tau(f) approximately 16 micros, tau(s) approximately 1 ms). This voltage dependence is inconsistent with a previously published gating model for CLC-1 (Fahlke, C., A. Rosenbohm, N. Mitrovic, A.L. George, and R. Rüdel. 1996. Biophys. J. 71:695-706). The kinetic difference at 200 mV allowed us to separate the steady state open probabilities of the two processes assuming that they reflect two parallel (not necessarily independent) gates that have to be open simultaneously to allow ion conduction. Both open probabilities could be described by Boltzmann functions with gating valences around one and with nonzero "offsets" at negative voltages, indicating that the two "gates" never close completely. For comparison with single channel data and to correlate the two gating processes with the two gates of CLC-0, we characterized their voltage, pH(int), and [Cl](ext) dependence, and the dominant myotonia inducing mutation, I290M. Assuming a double-barreled structure of CLC-1, our results are consistent with the identification of the fast and slow gating processes with the single-pore and the common-pore gate, respectively.

Pharmacological characterization of chloride channels belonging to the ClC family by the use of chiral clofibric acid derivatives.

The enantiomers of 2-(p-chlorophenoxy)propionic acid (CPP) and of its analogs with substitutions on the asymmetric carbon atom were tested on human ClC-1 channel, the skeletal muscle chloride channel, after heterologous expression in Xenopus laevis oocytes, to gain insight in the mechanism of action of these stereoselective modulators of macroscopic chloride conductance (gCl) of rat striated fibers. By means of two microelectrode voltage clamp recordings, we found that S(-)-CPP shifted the activation curve of the ClC-1 currents toward more positive potentials and decreased the residual conductance at negative membrane potential; both effects probably account for the decrease of gCl at resting potential of native muscle fibers. Experiments on expressed Torpedo marmorata ClC-0 channels and a mutant lacking the slow gate suggest that S(-)-CPP could act on the fast gate of the single protochannels constituting the double-barreled structure of ClC-0 and ClC-1. The effect of S(-)-CPP on ClC-1 was markedly increased at low external pH (pH = 6), possibly for enhanced diffusion through the membrane (i.e., because the compound was effective only when applied to the cytoplasmic side during patch clamp recordings). The R(+)-isomer had little effect at concentrations as high as 1 mM. The CPP analogs with an ethyl, a phenyl, or an n-propyl group in place of the methyl group on the asymmetric center showed a scale of potency and a stereoselective behavior on ClC-1 similar to that observed for blocking gCl in native muscle fibers. The tested compounds were selective toward the ClC-1 channel. In fact, they were almost ineffective on an N-terminal deletion mutant of ClC-2 that is volume- and pH-independent while they blocked wild-type ClC-2 currents only at high concentrations and independently of pH and drug configuration, suggesting a different mechanism of action compared with ClC-1. No effects were observed on ClC-5 that shows less than 30% homology with ClC-1. Thus, CPP-like compounds may be useful both to gain insight into biophysical properties of ClC-1 and for searching tissue-specific therapeutic agents.

Chloride channels activated by hypotonicity in N2A neuroblastoma cell line.

By using the patch-clamp technique we have shown that, in hypotonic extracellular solutions, the mouse neuroblastoma cells Neuro2A (N2A) develop ionic currents mediated by a chloride-selective channel which is also permeable to other anions in accordance with the permeability sequence: I->Br->Cl->gluconate->glutamate-. The currents persist for several hours when Mg-ATP is present in the recording pipette but occur only transiently in the absence of Mg-ATP. Typical blockers of anions channels such as La3+ and Zn2+ do not affect the hypotonicity-activated channel; conversely, the stilbene sulfonate-derivatives, 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS) and 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), reversibly inhibit the channel in a voltage-dependent manner. Also intact cells exposed to hyposmotic solutions activate volume-regulation mechanisms which decrease the transient volume increase that develops immediately after the application of the hyposmotic challenge. Since N2A neurons have been used as an expression system of exogenous channels, the presence of osmolarity-regulated channels in these cells is an important aspect that deserves the attention of researchers who may wish to express and study the properties of transport proteins in this cell line.