Enhanced excitability of small dorsal root ganglion neurons in rats with bone cancer pain

<p>Abstract</p> <p>Background</p> <p>Primary and metastatic cancers that affect bone are frequently associated with severe and intractable pain. The mechanisms underlying the development of bone cancer pain are largely unknown. The aim of this study was to determine whether enhanced excitability of primary sensory neurons contributed to peripheral sensitization and tumor-induced hyperalgesia during cancer condition. In this study, using techniques of whole-cell patch-clamp recording associated with immunofluorescent staining, single-cell reverse-transcriptase PCR and behavioral test, we investigated whether the intrinsic membrane properties and the excitability of small-sized dorsal root ganglion (DRG) neurons altered in a rat model of bone cancer pain, and whether suppression of DRG neurons activity inhibited the bone cancer-induced pain.</p> <p>Results</p> <p>Our present study showed that implantation of MRMT-1 tumor cells into the tibial canal in rats produced significant mechanical and thermal hyperalgesia in the ipsilateral hind paw. Moreover, implantation of tumor cells provoked spontaneous discharges and tonic excitatory discharges evoked by a depolarizing current pulse in small-sized DRG neurons. In line with these findings, alterations in intrinsic membrane properties that reflect the enhanced neuronal excitability were observed in small DRG neurons in bone cancer rats, of which including: 1) depolarized resting membrane potential (RMP); 2) decreased input resistance (R_in); 3) a marked reduction in current threshold (CT) and voltage threshold (TP) of action potential (AP); 4) a dramatic decrease in amplitude, overshot, and duration of evoked action potentials as well as in amplitude and duration of afterhyperpolarization (AHP); and 5) a significant increase in the firing frequency of evoked action potentials. Here, the decreased AP threshold and increased firing frequency of evoked action potentials implicate the occurrence of hyperexcitability in small-sized DRG neurons in bone cancer rats. In addiotion, immunofluorescent staining and single-cell reverse-transcriptase PCR revealed that in isolated small DRG neurons, most neurons were IB4-positive, or expressed TRPV1 or CGRP, indicating that most recorded small DRG neurons were nociceptive neurons. Finally, using in vivo behavioral test, we found that blockade of DRG neurons activity by TTX inhibited the tumor-evoked mechanical allodynia and thermal hyperalgesia in bone cancer rats, implicating that the enhanced excitability of primary sensory neurons underlied the development of bone cancer pain.</p> <p>Conclusions</p> <p>Our present results suggest that implantation of tumor cells into the tibial canal in rats induces an enhanced excitability of small-sized DRG neurons that is probably as results of alterations in intrinsic electrogenic properties of these neurons. Therefore, alterations in intrinsic membrane properties associated with the hyperexcitability of primary sensory neurons likely contribute to the peripheral sensitization and tumor-induced hyperalgesia under cancer condition.</p

Diaqua­bis­(1-methyl-1H-imidazole-κN 3)bis­[2-(naphthalen-1-yl)acetato-κO]cobalt(II)

In the title compound, [Co(C12H9O2)2(C4H6N2)2(H2O)2], the CoII ion is located on an inversion centre and displays a distorted octa­hedral coordination geometry. Two O atoms from two water mol­ecules and two carboxyl­ate O atoms from two 2-(naphthalen-1-yl)acetate ligands are in the equatorial plane and two N atoms from two 1-methyl-1H-imidazole ligands are in the axial positions. The structure is stabilized by intra­molecular O—H⋯O hydrogen bonds. Inter­molecular O—H⋯O hydrogen bonds link the complex mol­ecules into chains along [100]

Bis­(2-methyl-1H-imidazole-κN 3)bis[2-(naphthalen-2-yl)acetato-κO]copper(II)

In the crystal structure of the title compound, [Cu(C12H9O2)2(C4H6N2)2], the Cu(II) cations are square-planar coordinated by two 1-naphthyl­acetate anions and two 2-methyl-imidazole ligands into discrete complexes that are located on centres of inversion. These complexes are linked into chains parallel to [010] by inter­molecular N—H⋯O hydrogen bonding between the N—H H atom of the 2-methyl-imidazole ligands and the carboxyl­ate O atoms that are not involved in metal coordination

Pyrrolidin-1-ium 2-(naphthalen-1-yl)acetate–2-(naphthalen-1-yl)acetic acid (1/1)

In the title compound, C4H10N+·C12H9O2 −·C12H10O2, the pyrrolidine ring adopts an envelope conformation and the dihedral angle between the planes of the two naphthalene ring systems is 8.34 (10)°. The crystal structure is stabilized by O—H⋯O and N—H⋯O hydrogen bonds

Effect of Hydraulic Activity on Crystallization of Precipitated Calcium Carbonate (PCC) for Eco-Friendly Paper

Wt% of aragonite, a CaCO3 polymorph, increased with higher hydraulic activity (°C) of limestone in precipitated calcium carbonate (PCC) from the lime-soda process (Ca(OH)2-NaOH-Na2CO3). Only calcite, the most stable polymorph, was crystallized at hydraulic activity under 10 °C, whereas aragonite also started to crystallize over 10 °C. The crystallization of PCC is more dependent on the hydraulic activity of limestone than CaO content, a factor commonly used to classify limestone ores according to quality. The results could be effectively applied to the determination of polymorphs in synthetic PCC for eco-friendly paper manufacture

Bis(1H-benzimidazole-κN 3)bis­[2-(naphthalen-1-yl)acetato-κ2 O,O′]nickel(II) monohydrate

In the title compound, [Ni(C12H9O2)2(C7H6N2)2]·H2O, The NiII cation is located on a twofold rotation axis and is six-coordinated in a distorted NiN2O4 octa­hedral geometry. The asymmetric unit consists of a nickel(II) ion, one 2-(naphthalen-1-yl)acetate anion, a neutral benzotriazole ligand and one half of a lattice water mol­ecule. The crystal packing is stabilized by O—H⋯O and N—H⋯O hydrogen bonds. The title compound is isotypic with its CdII analogue

Successful management of heterotopic cornual pregnancy with laparoscopic cornual resection

AbstractObjectiveTo examine the feasibility of laparoscopic cornual resection for the treatment of heterotopic cornual pregnancy.Study designWomen who underwent laparoscopic cornual resection for heterotopic cornual pregnancy at our hospital between January 2003 and March 2015 were retrospectively analyzed. We evaluated significant parameters such as operative complications and postoperative pregnancy outcomes of concomitant pregnancy.ResultsThirteen patients with heterotopic cornual pregnancy were included in the study. All were pregnant through assisted reproductive technology, and the diagnosis was made at a median of 6+6 weeks (range 5+4–10+0). They were successfully treated with laparoscopic cornual resection and admitted for a median of 4 days (range, 2–7) postoperatively. The median operative time was 65min (range, 35–145min) and estimated blood loss was 200mL (range, 10–3000mL). There was a spontaneous abortion at 7+6 gestational weeks in a patient who received bilateral cornual resection. Seven patients delivered babies at term and 3 at preterm. All 10 women delivered without any maternal or neonatal complications. Two were lost to follow-up.ConclusionsLaparoscopic cornual resection is a feasible primary approach for the management of heterotopic cornual pregnancy

Bis(1-methyl-1H-imidazole-κN 3)bis­[2-(naphthalen-1-yl)acetato-κO]copper(II) monohydrate

In the crystal structure of the title compound, [Cu(C12H9O2)2(C4H6N2)2]·H2O, the CuII atom is coordinated by two 2-(naphthalen-1-yl)acetate anions and two 1-methyl­imidazole ligands, giving monomeric complexes with a square-planar coordination environment. Two complex mol­ecules and two water mol­ecules form a centrosymmetric ring system via O—H⋯O hydrogen bonds