Pressure-induced colossal piezoresistance effect and the collapse of the polaronic state in the bilayer manganite (La(0.4)Pr(0.6))(1.2)Sr(1.8)Mn2O7

We have investigated the effect of hydrostatic pressure as a function of temperature on the resistivity of a single crystal of the bilayer manganite (La(0.4)Pr(0.6))(1.2)Sr(1.8)Mn(2)O(7). Whereas a strong insulating behaviour is observed at all temperatures at ambient pressure, a clear transition into a metallic-like behaviour is induced when the sample is subjected to a pressure (P) of ~1.0 GPa at T < 70 K. A huge negative piezoresistance ~10(6) in the low temperature region at moderate pressures is observed. When the pressure is increased further (5.5 GPa), the high temperature polaronic state disappears and a metallic behaviour is observed. The insulator to metal transition temperature exponentially increases with pressure and the distinct peak in the resistivity that is observed at 1.0 GPa almost vanishes for P > 7.0 GPa. A modification in the orbital occupation of the e(g) electron between 3d(x(2)-y(2)) and 3d(z(2)-r(2)) states, as proposed earlier, leading to a ferromagnetic double-exchange phenomenon, can qualitatively account for our data.

What influences the acidity in the gastric conduit in patients who underwent cervical esophagogastrostomy for cancer?

The aim of this study was to determine the factors influencing acidity in the gastric conduit after esophagectomy for cancer. Acidity and bile reflux in the stomach and in the gastric conduit were examined by 24-h pH monitoring and bilimetry in 40 patients who underwent transthoracic subtotal esophagectomy followed by esophageal reconstruction using a gastric conduit, which was pulled up to the neck through a posterior mediastinal route in 17 patients, through a retrosternal route in 10 patients, and through a subcutaneous route in 13 patients. They were examined at 1 week before surgery, at 1 month after surgery, and at 1 year after surgery. Helicobacter pylori infection was examined pathologically and using the (13) C-urea breath test. The factors influencing acidity of the gastric conduit were analyzed using the stepwise regression model. Gastric acidity assessed by percentage (%) time of pH < 4 was reduced after surgery and was significantly less in patients with H. pylori infection compared with those without H. pylori infection throughout the period from 1 week before surgery to 1 year after surgery. Duodenogastric reflux (DGR) assessed by % time absorbance > 0.14 into the lower portion of the gastric conduit was significantly increased after surgery throughout the period from 1 month after surgery to 1 year after surgery. Multivariate analysis showed that the acidity in the gastric conduit was influenced by H. pylori infection and DGR at 1 month after surgery, and by H. pylori infection and the route for esophageal reconstruction at 1 year after surgery. Acidity in the gastric conduit was significantly decreased after surgery. Acidity in the gastric conduit for esophageal substitutes is influenced by H. pylori infection and surgery. DGR influences the gastric acidity in the short-term after surgery, but not in the long-term after surgery.

Thoracic endovascular aortic repair for aortic complications after esophagectomy for cancer: report of three cases

Aortic complications after esophageal cancer surgery are rare and usually fatal. Here, we report three patients who underwent thoracic endovascular aortic repair (TEVAR) for aortic complications after esophagectomy for cancer. In the first case, aortic rupture was caused by pyothorax due to residual tumor after esophagectomy. In the second case, aortic rupture was caused by pyothorax due to anastomotic leakage. In the third case, a pseudoaneurysm was caused by surgical injury during esophagectomy. TEVAR was safe and effective for severe aortic complications when graft infection was avoided. The first case died of sepsis on the 84th postoperative day, and the other two cases have survived 4 years and 2 years to date.

Elimination of adult-born neurons in the olfactory bulb is promoted during the postprandial period

Granule cells (GCs) in the mouse olfactory bulb (OB) continue to be generated in adulthood, with nearly half incorporated and the remainder eliminated. Here, we show that elimination of adult-born GCs is promoted during a short time window in the postprandial period. Under restricted feeding, the number of apoptotic GCs specifically increased within a few hours after the start of feeding. This enhanced GC apoptosis occurred in association with postprandial behaviors that included grooming, resting, and sleeping, and was particularly correlated with the length of postprandial sleep. Further, deprivation of olfactory sensory experience in the local OB area potentiated the extent of GC elimination in that area during the postprandial period. Sensory experience-dependent enhancement of GC elimination also occurred during postprandial period under natural feeding condition. These results suggest that extensive structural reorganization of bulbar circuitry occurs during the postprandial period, reflecting sensory experience during preceding waking period.

Azotobacter vinelandii gene clusters for two types of peptidic and catechol siderophores produced in response to molybdenum

AIM

To characterize the complementary production of two types of siderophores in Azotobacter vinelandii.

METHODS AND RESULTS

In an iron-insufficient environment, nitrogen-fixing A. vinelandii produces peptidic (azotobactin) and catechol siderophores for iron uptake to be used as a nitrogenase cofactor. Molybdenum, another nitrogenase cofactor, was also found to affect the production level of siderophores. Wild-type cells excreted azotobactin into molybdenum-supplemented and iron-insufficient medium, although catechol siderophores predominate in molybdenum-free environments. Two gene clusters were identified to be involved in the production of azotobactin and catechol siderophores through gene annotation and disruption. Azotobactin-deficient mutant cells produced catechol siderophores under the molybdenum-supplemented and iron-insufficient conditions, whereas catechol siderophore-deficient mutant cells extracellularly secreted excess azotobactin under iron-deficient condition independent of the concentration of molybdenum. This evidence suggests that a complementary siderophore production system exists in A. vinelandii.

CONCLUSIONS

Molybdenum was found to regulate the production level of two types of siderophores. Azotobacter vinelandii cells are equipped with a complementary production system for nitrogen fixation in response to a limited quantity of metals.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study identifying A. vinelandii gene clusters for the biosynthesis of two types of siderophores and clarifying the relationship between them.

Outcome of laparoscopic surgery for colon cancer in elderly patients

INTRODUCTION

The aim of this study was to evaluate whether elderly patients with colorectal cancer benefit from laparoscopic colon surgery (LAC) in comparison to open colon surgery (OC).

METHODS

Patients with colon cancer were divided into four groups; >75 years (CC(>75) ) [LAC(>75) (n=36), OC(>75) (n=15)] and ≤75 years [LAC(≤75) (n=90), OC(≤75) (n=26)]. Differences in postoperative short-term outcomes were analyzed among the age and procedure groups.

RESULTS

Intraoperative blood loss was significantly less in the LAC(>75) group (68 ± 168 ml) than in the OC(>75) group (118 ± 130 ml, P=0.040). The C-reactive protein of patients in the OC(>75) group (5.4 ± 2.2 mg/dl) tended to be less than that of the LAC(>75) group (6.1 ± 2.8 mg/dl, P=0.080) on postoperative day 1. The time to the first passage of flatus was significantly shorter in the LAC(>75) group (2.0 ± 0.7 days) than in the OC(>75) group (2.7 ± 0.8 days, P=0.003). Postoperative hospital stays were also shorter in the LAC(>75) group (14.2 ± 9.4 days) than in the OC(>75) group (18.0 ± 8.3 days, P=0.038). No mortality was registered in the LAC(>75) group, while one patient in the OC(>75) group died during the postoperative course. The rate of postoperative morbidity was similar between the LAC(>75) and OC(>75) groups [13.9% (5/36) versus 20.0% (3/15), P=0.679].

CONCLUSION

LAC provides some advantages over OC in patients with colon cancer aged >75 years as well as in those aged ≤75 years. LAC can be safely performed in very elderly patients with colon cancer.

Outcomes of multimodality therapy for stage IVB esophageal cancer with distant organ metastasis (M1-Org)

Esophageal cancer patients with distant organ metastasis have usually been treated only to palliate symptoms without multimodality therapy. The current study evaluates the role of multimodality therapy in esophageal squamous cell cancer patients with distant organ metastasis. Between February 1988 and January 2007, 80 esophageal squamous cell cancer patients with distant organ metastases were treated at our institution. Multimodality therapy was performed in 58 patients: 43 patients received chemoradiotherapy, 13 underwent surgery followed by chemotherapy and/or radiation therapy, and two received chemotherapy or chemoradiotherapy followed by surgery. Thirteen patients received single-modality therapy; chemotherapy, radiotherapy, or surgery alone. The remaining nine patients received best supportive care alone. The metastatic organ was the liver (n= 40), the lungs (n= 33), bone (n= 10), and other (n= 6). Nine patients had metastasis in two organs. There was no difference in the median survival among the sites of organ metastasis, lung, liver, or bone (P= 0.8786). The survival of patients treated with multimodality therapy was significantly better than that of the patients who received single-modality therapy or best supportive care alone (P < 0.0001). In patients treated with multimodallity therapy, there was no difference in survival for patients treated with surgery compared with patients treated without surgery (P= 0.1291). This retrospective study involves an inevitable issue of patient selection bias. However, these results suggested that multimodality therapy could improve survival of the esophageal squamous cell cancer patients with distant organ metastasis.

Anti-tumour effects of transcatheter arterial embolisation administered in combination with thalidomide in a rabbit VX2 liver tumour model

OBJECTIVE

Using a liver tumour model we investigated whether thalidomide enhances the anti-tumour effect of transcatheter arterial embolisation (TAE).

METHOD

First, the viability of VX2 tumour cells co-cultured with thalidomide in a 21% and 1% O(2) atmosphere was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Second, we randomly assigned 20 rabbits bearing VX2 liver tumours to 4 groups: Group 1 (thalidomide plus TAE), Group 2 (TAE only), Group 3 (thalidomide only) and Group 4 (control). Thalidomide was orally administered for 5 days. The anti-tumour effects were assessed by the tumour proliferation rate using MRI and by immunohistochemical analysis of the area of intratumoural vessels. Analysis of variance and Tukey's honestly significant difference test were used for statistical analysis.

RESULTS

The viability of cells grown under hypoxic and normal conditions was not significantly different, nor was there a difference among the four groups. The tumour size increased by 55.9±29.3% in Group 1, 250.6±73.3% in Group 2, 355.2±51.7% in Group 3 and 424.7±110.7% in Group 4; the difference between Group 1 and the other three groups was significant. The area of intratumour vessels in specimens was 0.22±0.28% in Group 1, 0.42±0.29% in Group 2, 1.44±1.00% in Group 3 and 6.00±2.17% in Group 4; the difference between Group 1 and the other groups was statistically significant, as was the difference between Groups 3 and 4.

CONCLUSION

Thalidomide used in combination with TAE enhanced anti-tumour effects in rabbits bearing VX2 liver tumours.

Surgical management for small cell carcinoma of the esophagus

Esophageal small cell carcinoma (SmCC) has been regarded as a rare and aggressive tumor with early metastasis. The optimal treatment has not yet been established, and the role of surgery has remained controversial. In this retrospective study, we report seven cases studies of SmCC of the esophagus and analyze the clinical outcomes after surgery. Between 1986 and 2007, there were seven patients with esophageal SmCC treated surgically in our institution. All the patients with clinically limited disease underwent transthoracic esophagectomy with lymphadenectomy. Lymph node involvement was found in all cases irrespective of the depth of tumor invasion. Three of the seven patients were diagnosed as having an extensive disease on pathological examination after esophagectomy. Five patients received postoperative chemotherapy. Two patients are alive with no recurrence at 16 months and at 45 months after surgery. Another one without chemotherapy survived 93 months and died of another disease. The remaining four patients died of recurrent disease or another disease. The median overall survival to date of these patients was 16 months (range 12-93 months). Esophagectomy with lymphadenectomy resulted in a relatively better survival in some patients with esophageal SmCC. We concluded that surgery may be helpful as part of multimodality treatment in selected patients with esophageal SmCC.

Pharyngolaryngeal reflux in patients who underwent cervical esophago-gastrostomy following esophagectomy

Pharyngolaryngeal reflux has been generally accepted as a cause for pharyngolaryngitis, hoarseness, aspiration pneumonia, chronic cough, and nocturnal asthma. Although patients who have undergone gastric conduit reconstruction after esophagectomy are at a high risk to pharyngolaryngeal reflux disease (PLRD), PLRD after esophagectomy is still unknown. The aim of this study is to investigate the correlation between reflux pharyngolaryngitis and acid reflux into the hypopharynx and into the cervical esophagus in patients who have undergone cervical esophagogastrostomy. We enrolled 62 patients who received follow-up endoscopy and 24-h pH monitoring after cervical esophagogastrostomy. These included 26 at 1 month after surgery and 36 at 1 year or more after surgery. We investigated: (i) the correlation between the extent of reflux pharyngolaryngitis and that of reflux esophagitis based on endoscopic findings; and (ii) the correlation between the extent of reflux pharyngolaryngitis and that of acid exposure -'% time pH < 4' measured by 24-h pH monitoring - in the hypopharynx and in the cervical esophagus, and of acidity in the gastric conduit. There was no difference in acid exposure between the hypopharynx and the cervical esophagus according to time after surgery. However, the acidity in the gastric conduit was significantly more at one year or more after surgery compared with acidity at 1 month after surgery (P= 0.001). There was a significant correlation between acid exposure in the hypopharynx and that in the cervical esophagus (P < 0.001), although acid exposure in the hypopharynx was significantly less than that in the cervical esophagus (P < 0.001). A significant correlation between reflux pharyngolaryngitis and reflux esophagitis was observed (P < 0.001). There was a significant correlation between reflux pharyngolaryngitis and acid exposure in the hypopharynx (P= 0.021), and also that in the proximal esophagus (P= 0.001). The correlation between the extent of reflux pharyngolaryngitis and the acidity in the gastric conduit was not observed. These findings are consistent with pharyngolaryngitis being caused by gastro-esophago-pharyngolaryngeal reflux in patients after cervical esophagogastrostomy, despite the upper esophageal sphincter strongly preventing acid reflux from the cervical esophagus into the hypopharynx.

Male effect pheromone tickles the gonadotrophin-releasing hormone pulse generator

In sheep and goats, the primer pheromone produced by the male induces out-of-seasonal ovulation in anoestrous females, the so-called 'male effect.' Because the initial endocrine event following reception of the pheromone is the stimulation of pulsatile luteinising hormone (LH) secretion, the central target of the pheromone is considered to be the putative gonadotrophin-releasing hormone (GnRH) pulse generator. Using electrophysiological techniques to record multiple-unit activity (MUA) in close proximity to kisspeptin neurones in the arcuate nucleus (ARC) of Shiba goats, we found that bursts (volleys) of MUA occur at regular intervals, and repetitive bursts are invariably associated with discrete pulses of LH, suggesting that the ARC kisspeptin neurones may be the intrinsic source of the GnRH pulse generator. A brief exposure of female goats to the pheromone immediately elicited an instantaneous rise in MUA, which is followed by an MUA volley and an accompanying LH pulse, indicating that the pheromone signal is transmitted to a subset of the ARC kisspeptin neurones to activate them. Because it has been suggested that the neurokinin B and dynorphin coexpressed in those neurones play critical roles in generating rhythmic bursts, they may be involved in the intracellular pheromone actions that are responsible for inducing the GnRH pulse.