Circular muscle contraction in the mice rectum plays a key role in morphine-induced constipation

BACKGROUND

Although opioids induce intestinal muscle contraction and provoke constipation, the intestinal region(s) that contribute to the constipation have remained unclear. We report here a region-specific response of intestinal muscle contraction to morphine and its correlation with in vivo constipation.

METHODS

Regions of mice small and large intestines were dissected histologically and circular muscle contractile responses were measured using isometric transducers. Bead expulsion assays were performed to assess in vivo constipation.

KEY RESULTS

The strongest contraction in response to morphine was detected in the rectum. The distal and transverse colon also showed strong contractions, whereas weak responses were detected in the proximal colon, jejunum, and ileum. Regarding the sustainability of muscle contractions during morphine exposure, prolonged waves were detected only in the rectum, while the waves diminished gradually in other regions. To identify the mechanism(s) underlying this difference, we focused on nitric oxide synthase (NOS). In the distal colon, decreased contraction during morphine exposure was recovered by application of a NOS inhibitor (L-NAME), while a NOS substrate (L-arginine) enhanced contractile degradation. In contrast L-NAME and L-arginine modestly affected the sustained contraction in the rectum. To confirm the correlation with constipation, beads were inserted into the transverse colon, distal colon, or rectum after morphine administration and expulsion times were examined. Beads tended to stop at the rectum even when inserted in the deeper colonic regions.

CONCLUSIONS & INFERENCES

The rectum showed the greatest response to morphine in both in vitro and in vivo analyses, therefore it may play a key role for opioid-induced constipation.

Development and external validation of a nomogram for overall survival after curative resection in serosa-negative, locally advanced gastric cancer

BACKGROUND

Few nomograms can predict overall survival (OS) after curative resection of advanced gastric cancer (AGC), and these nomograms were developed using data from only a few large centers over a long time period. The aim of this study was to develop and externally validate an elaborative nomogram that predicts 5-year OS after curative resection for serosa-negative, locally AGC using a large amount of data from multiple centers in Japan over a short time period (2001-2003).

PATIENTS AND METHODS

Of 39 859 patients who underwent surgery for gastric cancer between 2001 and 2003 at multiple centers in Japan, we retrospectively analyzed 5196 patients with serosa-negative AGC who underwent Resection A according to the 13th Japanese Classification of Gastric Carcinoma. The data of 3085 patients who underwent surgery from 2001 to 2002 were used as a training set for the construction of a nomogram and Web software. The data of 2111 patients who underwent surgery in 2003 were used as an external validation set.

RESULTS

Age at operation, gender, tumor size and location, macroscopic type, histological type, depth of invasion, number of positive and examined lymph nodes, and lymphovascular invasion, but not the extent of lymphadenectomy, were associated with OS. Discrimination of the developed nomogram was superior to that of the TNM classification (concordance indices of 0.68 versus 0.61; P < 0.001). Moreover, calibration was accurate.

CONCLUSIONS

We have developed and externally validated an elaborative nomogram that predicts the 5-year OS of postoperative serosa-negative AGC. This nomogram would be helpful in the assessment of individual risks and in the consideration of additional therapy in clinical practice, and we have created freely available Web software to more easily and quickly predict OS and to draw a survival curve for these purposes.

Improved corneal toxicity and permeability of tranilast by the preparation of ophthalmic formulations containing its nanoparticles

We prepared ophthalmic formulations containing 0.5% tranilast (TL) nanoparticles using 0.005% benzalkonium chloride (BAC), 0.5% D-mannitol, and 2-hydroxypropyl-β-cyclodextrin (HPβCD), and investigated their usefulness in the ophthalmologic field by evaluating corneal toxicity and permeability. TL nanoparticles were prepared using zirconia beads and Bead Smash 12, which allowed the preparation of high quality dispersions containing 0.5% TL nanoparticles (particle size, 34 ± 20 nm, means ± S.D.). Dispersions containing TL nanoparticles are tolerated better by human corneal epithelium cells than a commercially available 0.5% TL preparation (RIZABEN(®) eye drops). In addition, the addition of TL nanoparticles to the dispersions does not affect the antimicrobial activity of BAC against Escherichia coli (ATCC 8739), and the corneal penetration of TL from dispersions containing TL nanoparticles was significantly higher than in the case of the commercially available 0.5% TL eye drops. It is possible that dispersions containing TL nanoparticles will show increased effectiveness against ocular inflammation, and that ocular drug delivery systems using drug nanoparticles may lead to an expansion of their usefulness for therapy in the ophthalmologic field.

A blue-shifted light-driven proton pump for neural silencing

Ion-transporting rhodopsins are widely utilized as optogenetic tools both for light-induced neural activation and silencing. The most studied representative is Bacteriorhodopsin (BR), which absorbs green/red light (∼570 nm) and functions as a proton pump. Upon photoexcitation, BR induces a hyperpolarization across the membrane, which, if incorporated into a nerve cell, results in its neural silencing. In this study, we show that several residues around the retinal chromophore, which are completely conserved among BR homologs from the archaea, are involved in the spectral tuning in a BR homolog (HwBR) and that the combination mutation causes a large spectral blue shift (λmax = 498 nm) while preserving the robust pumping activity. Quantum mechanics/molecular mechanics calculations revealed that, compared with the wild type, the β-ionone ring of the chromophore in the mutant is rotated ∼130° because of the lack of steric hindrance between the methyl groups of the retinal and the mutated residues, resulting in the breakage of the π conjugation system on the polyene chain of the retinal. By the same mutations, similar spectral blue shifts are also observed in another BR homolog, archearhodopsin-3 (also called Arch). The color variant of archearhodopsin-3 could be successfully expressed in the neural cells of Caenorhabditis elegans, and illumination with blue light (500 nm) led to the effective locomotory paralysis of the worms. Thus, we successfully produced a blue-shifted proton pump for neural silencing.

Magnetic phase diagram of clathrate compound Ce3Pd20Si6 with quadrupolar ordering

We present results of specific heat measurements on a Ce3Pd20Si6 single crystal and construct the magnetic phase diagram for the three cubic principal directions [100], [110] and [111]. The highly anisotropic phase diagram is discussed and can be qualitatively explained by the Zeeman splitting at the 8c-site. For B ‖ [100], the present study found two different quadrupolar ordered phases, which meet the paramagnetic phase at a tri-critical point and establish the new phase boundaries.

Effects of milnacipran, a 5-HT and noradrenaline reuptake inhibitor, on C-fibre-evoked field potentials in spinal long-term potentiation and neuropathic pain

BACKGROUND AND PURPOSE

The analgesic action of 5-HT and noradrenaline reuptake inhibitors (SNRIs) on nociceptive synaptic transmission in the spinal cord is poorly understood. We investigated the effects of milnacipran, an SNRI, on C-fibre-evoked field potentials (FPs) in spinal long-term potentiation (LTP), a proposed synaptic mechanism of hypersensitivity, and on the FPs in a neuropathic pain model.

EXPERIMENTAL APPROACH

C-fibre-evoked FPs by electrical stimulation of the sciatic nerve fibres were recorded in the spinal dorsal horn of anaesthetized adult rats, and LTP was induced by high-frequency stimulation of the sciatic nerve fibres. A rat model of neuropathic pain was produced by L5 spinal nerve ligation and transection.

KEY RESULTS

Milnacipran produced prolonged inhibition of C-fibre-evoked FPs when applied spinally after the establishment of LTP of C-fibre-evoked FPs in naïve animals. In the neuropathic pain model, spinal administration of milnacipran clearly reduced the basal C-fibre-evoked FPs. These inhibitory effects of milnacipran were blocked by spinal administration of methysergide, a 5-HT½ receptor antagonist, and yohimbine or idazoxan, α₂-adrenoceptor antagonists. However, spinal administration of milnacipran in naïve animals did not affect the basal C-fibre-evoked FPs and the induction of spinal LTP.

CONCLUSION AND IMPLICATIONS

Milnacipran inhibited C-fibre-mediated nociceptive synaptic transmission in the spinal dorsal horn after the establishment of spinal LTP and in the neuropathic pain model, by activating both spinal 5-hydroxytryptaminergic and noradrenergic systems. The condition-dependent inhibition of the C-fibre-mediated transmission by milnacipran could provide novel evidence regarding the analgesic mechanisms of SNRIs in chronic pain.

Anti-carcinogenic activity of 6-methylsulfinylhexyl isothiocyanate-, an active anti-proliferative principal of wasabi (Eutrema wasabi Maxim.)

Synthetic 4-methylsulfinylhexyl isothiocyanate (MITC)(a potent inducer of phase 2 detoxification enzymes from broccoli) and 6-MITC(a potent anti-proliferative principal from wasabi) slightly inhibited the induction of mouse skin tumor in a two-stage process of carcinogenesis (initiator, 9,10-dimethyl-1,2-benzanthracene; promotor,12-o-tetradecanoylphorbol-13-acetate), but the effect was not significant. Both compounds, however, significantly inhibited the mutation of skin resulting from topical applications of the carcinogens. When a murine hepatoma cell line, Hepa 1c1c7, was treated with 2-,4-,6- and 8-MITCs, they augmented the induction of its quinone reductase, one of the phase 2 detoxification enzymes in a concentration dependent manner, and the 4- and 6-MITCs were much more potent on the reduction of the enzyme than the 2- and 8-MITCs. All 2-, 4-, 6- and 8-MITCs suppressed the growth of murine tumor cells, their suppressive activities being proportional to the length of their methyl residue. They were also cytotoxic to mouse peritoneal exudate macrophages which were not proliferating in vitro, indicating that the cellular targets of isothiocyanate may not be dependent upon the cell cycle. In addition, all the 2-, 4-, 6- and 8-MITCs inhibited the production of nitric oxide (a potent radical carcinogen) by peritoneal macrophages.

Clinical outcomes of endoscopic submucosal dissection for early gastric cancer in remnant stomach or gastric tube

BACKGROUND AND STUDY AIMS

Little information exists regarding the optimal treatment of early gastric cancer (EGC) in a remnant stomach or gastric tube. The aim of this study was to assess the feasibility and clinical outcomes of endoscopic submucosal dissection (ESD) for EGC in a remnant stomach and gastric tube.

PATIENTS AND METHODS

Between September 2002 and December 2009, ESD was performed in 62 lesions in 59 patients with EGC in a remnant stomach (48 lesions) or gastric tube (14 lesions). Clinicopathological data were retrieved retrospectively to assess the en bloc resection rate, complications, and outcomes. Treatment results were assessed according to the indications for endoscopic resection, and were compared with those of ESD performed in a whole stomach during the same study period.

RESULTS

The en bloc resection rates for lesions within the standard and expanded indication were 100 % and 93 %, respectively. Postoperative bleeding occurred in five patients (8 %). The perforation rate was significantly higher (18 %, 11 /62) than that of ESD in a whole stomach (5 %, 69 /1479). Among the perforation cases, eight lesions involved the anastomotic site or stump line, and ulcerative changes were observed in five lesions. The 3-year overall survival rate was 85 %, with eight deaths due to other causes and no deaths from gastric cancer.

CONCLUSION

A high en bloc resection rate was achieved by ESD for EGC in a remnant stomach or gastric tube; however, this procedure is still technically demanding due to the high complication rate of perforation.

Expression of smooth muscle calponin in synovial sarcoma

Purpose. Histogenesis of synovial sarcoma remains controversial and reliable molecular markers for diagnosis are necessary. Expression of basic calponin, a smooth muscle differentiation-specific actin-binding protein, was studied in synovial sarcoma.Subjects and Methods. The basic calponin gene and the gene product were analyzed by reverse transcription PCR analysis (RT-PCR) and immunohistochemistry in 14 synovial sarcomas and a human synovial sarcoma cell line (HS-SY-II).Results and Discussion. Immunoreactivity for basic calponin was detected in the cytoplasm of 6 synovial sarcomas (43% positive). In the basic calponin-positive tumors and the HS-SY-II cells, expression for smooth muscle-specific genes, including basic calponin and SM22alpha , was detected by RT-PCR, suggesting a lineage relationship between synovial sarcoma cells and smooth muscle-like mesenchymal cells.Conclusions. A subset of synovial sarcomas expressing the basic calponin gene and the gene product were identified. The basic calponin may have potential utility as a novel molecular marker identifying certain synovial sarcomas.

stx genotype and molecular epidemiological analyses of Shiga toxin-producing Escherichia coli O157:H7/H- in human and cattle isolates

The relationship between human diseases caused by infection with Shiga toxin (Stx)-producing Escherichia coli (STEC) O157 strains and O157 strains isolated from cattle was investigated in an area where stockbreeding is prolific. For this purpose, the stx genotypes, the molecular epidemiological characteristics of 268 STEC O157 strains including 211 human-origin strains and 57 cattle-origin strains, and clinical manifestations of 210 STEC-infected people were analyzed. Of 211 human-origin strains, 92 strains (44%) were of the stx1/stx2 genotype, and 74 strains (35%) were of the stx2c genotype. Most of the people infected with stx2c genotype strains presented no symptoms or mild symptoms such as slight diarrhea, except for 3 patients with bloody diarrhea. Of the 57 cattle-origin strains, 27 strains (47%) were of the stx2c genotype and 17 strains (30%) were of the stx1/stx2 genotype. Pulsed-field gel electrophoresis (PFGE) and insertion sequence (IS) analysis demonstrated that 11 isolates (41%) of the 27 cattle isolates of the stx2c genotype had high homology (>95% identity) with human isolates. These results suggest that some genetic patterns of the stx2c genotype strains might be preserved in cattle or their surrounding environment for several years, and during these periods, they might have opportunities to infect people through various routes. Because of the mild virulence of the stx2c genotype strains, they seemed to be transmitted asymptomatically from cattle to humans and then spread from person to person. It may be a public health concern. Further, they occasionally cause severe symptoms in humans; therefore, caution is warranted for infections by stx2c genotype O157 strains, in addition to stx2-possessing genotype O157 strains.

Risk factors for recurrence of artificial gastric ulcers after endoscopic submucosal dissection

It has been reported previously that artificial gastric ulcers caused by endoscopic submucosal dissection (ESD) would heal within 8 weeks, irrespective of their size and location. The aim of this retrospective study was to describe long-term outcomes of gastric ESD ulcers. Check-up of ulcers was performed by periodic endoscopy. The rate of ESD ulcer recurrence and clinicopathological factors that may relate to recurrence were assessed. During the median observation period of 33 months, a benign ulcer recurrence occurred in 10 lesions in 10 patients (2.1%). Univariate analysis showed that Helicobacter pylori infection and presence of pathological ulcer findings within the ESD specimen were significantly related to the risk of ESD ulcer recurrence. Although the frequency is low, there is a possibility of ESD ulcer recurrence in patients with H. pylori infection and in patients who undergo ESD for a lesion with ulceration.

Blue Light Emission from Silicon Ultrafine Particles

The oxygen-containing silicon (Si) ultrafine particles have been deposited onto Si and SiO2 substrates by evaporation of Si powder in an oxygen-containing argon atmosphere. The asdeposited Si ultrafine particles exposed to the ultraviolet light emit blue light, which is strong enough to be seen with the naked eye. The blue light emission is associated with a broad photoluminescence (PL) peak at 2.7 eV, which is attributed to radiative recombination via a radiative recombination center. The proposed model with one radiative and two nonradiative recombination centers well explains the temperature-dependent PL peak intensity.

Effects of granule-bound starch synthase I-defective mutation on the morphology and structure of pyrenoidal starch in Chlamydomonas

Lowering of the CO₂ concentration in the environment induces development of a pyrenoidal starch sheath, as well as that of pyrenoid and CO₂-concentrating mechanisms, in many microalgae. In the green algae Chlamydomonas and Chlorella, activity of granule-bound starch synthase (GBSS) concomitantly increases under these conditions. In this study, effects of the GBSS-defective mutation (sta2) on the development of pyrenoidal starch were investigated in Chlamydomonas. Stroma starch- and pyrenoid starch-enriched samples were obtained from log-phase cells grown with air containing 5% CO₂ (high-CO₂ conditions favouring stromal starch synthesis) and from those transferred to low-CO₂ conditions (air level, 0.04% CO₂, favouring pyrenoidal starch synthesis) for 6h, respectively. In the wild type, total starch content per culture volume did not increase during the low-CO₂ conditions, in spite of the development of pyrenoidal starch, suggesting that degradation of some part of stroma starch and synthesis of pyrenoid starch simultaneously occur under these conditions. Even in the GBSS-deficient mutants, pyrenoid and pyrenoid starch enlarged after lowering of the CO₂ concentration. However, the morphology of the pyrenoid starch was thinner and more fragile than the wild type, suggesting that GBSS does affect the morphology of pyrenoidal starch. Surprisingly normal GBSS activity is shown to be required to obtain the high A-type crystallinity levels that we now report for pyrenoidal starch. A model is presented explaining how GBSS-induced starch granule fusion may facilitate the formation of the pyrenoidal starch sheath.

Effects of gastric acidity on peristomal infection after percutaneous endoscopic gastrostomy placement

Peristomal infection is a common complication following percutaneous endoscopic gastrostomy (PEG) placement. This study investigated the effect of gastric acidity on peristomal infection, including type of bacteria and the relationship between bacteria cultured from the oropharynx and PEG tube site. Sixty-seven patients with dysphagia underwent PEG placement at Otaki Hospital between 1998 and 2001. Gastric acidity was evaluated by 24h pH monitoring. Patients were observed for peristomal infection for two weeks after PEG placement, with specimens collected from the oropharynx and PEG tube site. Twenty-one (31.3%) of the patients who had undergone PEG insertion developed peristomal infections. Of 52 patients who were not colonised with meticillin-resistant Staphylococcus aureus (MRSA) in the oropharynx, 11 cases (21.2%) developed peristomal infection. The median gastric pH of infected patients (11 cases) was 5.05+/-2.55 (mean+/-SD) and in patients without infection (41 cases) it was 3.06+/-1.83 (P=0.019). Peristomal infection developed in 66.7% (10/15) of patients carrying MRSA compared with only 21.2% (11/52) of patients who were not colonised by MRSA (P<0.001). The incidence of peristomal infection was affected by gastric acidity and the presence of MRSA in the oropharynx.