Evidence for biological nitrification inhibition in Brachiaria pastures

Nitrification, a key process in the global nitrogen cycle that generates nitrate through microbial activity, may enhance losses of fertilizer nitrogen by leaching and denitrification. Certain plants can suppress soil-nitrification by releasing inhibitors from roots, a phenomenon termed biological nitrification inhibition (BNI). Here, we report the discovery of an effective nitrification inhibitor in the root-exudates of the tropical forage grass Brachiaria humidicola (Rendle) Schweick. Named "brachialactone," this inhibitor is a recently discovered cyclic diterpene with a unique 5-8-5-membered ring system and a gamma-lactone ring. It contributed 60-90% of the inhibitory activity released from the roots of this tropical grass. Unlike nitrapyrin (a synthetic nitrification inhibitor), which affects only the ammonia monooxygenase (AMO) pathway, brachialactone appears to block both AMO and hydroxylamine oxidoreductase enzymatic pathways in Nitrosomonas. Release of this inhibitor is a regulated plant function, triggered and sustained by the availability of ammonium (NH(4)(+)) in the root environment. Brachialactone release is restricted to those roots that are directly exposed to NH(4)(+). Within 3 years of establishment, Brachiaria pastures have suppressed soil nitrifier populations (determined as amoA genes; ammonia-oxidizing bacteria and ammonia-oxidizing archaea), along with nitrification and nitrous oxide emissions. These findings provide direct evidence for the existence and active regulation of a nitrification inhibitor (or inhibitors) release from tropical pasture root systems. Exploiting the BNI function could become a powerful strategy toward the development of low-nitrifying agronomic systems, benefiting both agriculture and the environment.

[Treatment of a persistent postoperative chylothorax with octreotide]

Chylothorax is a serious postoperative complication in the field of thoracic surgery. To treat refractory chylothorax, various methods including surgery are employed. In this study, we report a patient with refractory chylothorax in whom treatment with octreotide acetate was successful, although the chylorrhea site could not be determined during additional thoracotomy.

Risk factors for cardiac and pyloric stenosis after endoscopic submucosal dissection, and efficacy of endoscopic balloon dilation treatment

BACKGROUND AND STUDY AIMS

Bleeding and perforation are major complications of endoscopic submucosal dissection (ESD) for early gastric cancer (EGC), but post-ESD stenosis represents a severe delayed complication that can result in clinical symptoms such as dysphagia and nausea. The aims of this study were to determine the risk factors and evaluate the clinical treatment for post-ESD stenosis.

METHODS

A total of 2011 EGCs resected by ESD at our institution between 2000 and 2005 were reviewed retrospectively. Resection was defined as cardiac when any mucosal defect was located in the squamocolumnar junction, and as pyloric when any mucosal defect was located < 1 cm from the pylorus ring. Post-ESD stenosis was defined when a standard endoscope could not be passed through the stenosis. We examined the incidence of post-ESD stenosis, its relationship with relevant factors, and the clinical course of post-ESD stenosis patients.

RESULTS

Post-ESD stenosis occurred with seven of 41 cardiac resections (17 %) and eight of 115 pyloric resections (7 %). Circumferential extent of the mucosal defect of > 3/4 and longitudinal extent > 5 cm were each significantly related to occurrence of post-ESD stenosis with both cardiac and pyloric resections. All 15 affected patients were successfully treated by endoscopic balloon dilation.

CONCLUSIONS

A circumferential extent of the mucosal defect of > 3/4 or longitudinal extent of > 5 cm in length were both demonstrated to be risk factors for post-ESD stenosis, in both cardiac and pyloric resections, and endoscopic balloon dilation was shown to be effective in treating post-ESD stenosis.

Routine coagulation of visible vessels may prevent delayed bleeding after endoscopic submucosal dissection--an analysis of risk factors

BACKGROUND AND STUDY AIM

Endoscopic submucosal dissection (ESD) has been reported to be associated with a higher complication rate than standard endoscopic mucosal resection. We aimed to clarify the risk factors for delayed bleeding after ESD for early gastric cancer (EGC).

METHODS

1083 EGCs in 968 consecutive patients undergoing ESD during a 4-year period were reviewed. Post-ESD coagulation (PEC) preventive therapy of visible vessels in the resection area, using a coagulation forceps, was introduced and mostly performed during the later 2 years. Various factors related to patients, tumors, and treatment including PEC were investigated using univariate and multivariate analysis with regard to delayed post-ESD bleeding, evidenced by hematemesis or melena, that required endoscopic treatment.

RESULTS

Delayed bleeding occurred after ESD of 63 lesions (5.8 % of all lesions and 6.5 % of patients), controlled in all cases by endoscopic hemostasis; blood transfusion was required in only one case. Tumor location in the upper third of the stomach and PEC were independent factors indicating a lower rate of delayed bleeding according to both univariate and multivariate analysis.

CONCLUSIONS

This retrospective study suggested that preventive coagulation of visible vessels in the resection area after ESD may lead to a lower bleeding rate.

Efonidipine reduces proteinuria and plasma aldosterone in patients with chronic glomerulonephritis

Efonidipine, a dihydropirydine calcium channel blocker, has been shown to dilate the efferent glomerular arterioles as effectively as the afferent arterioles. The present study compared the chronic effects of efonidipine and amlodipine on proteinuria in patients with chronic glomerulonephritis. The study subjects were 21 chronic glomerulonephritis patients presenting with spot proteinuria greater than 30 mg/dL and serum creatinine concentrations of <or=1.3 mg/dL in men or <or=1.1 mg/dL in women. All patients were receiving antihypertensive medication or had a blood pressure >or=130/85 mmHg. Efonidipine 20-60 mg twice daily and amlodipine 2.5-7.5 mg once daily were given for 4 months each in a random crossover manner. In both periods, calcium channel blockers were titrated when the BP exceeded 130/85 mmHg. Blood sampling and urinalysis were performed at the end of each treatment period. The average blood pressure was comparable between the efonidipine and the amlodipine periods (133+/-10/86+/-5 vs. 132+/-8/86+/-5 mmHg). Urinary protein excretion was significantly less in the efonidipine period than in the amlodipine period (1.7+/-1.5 vs. 2.0+/-1.6 g/g creatinine, p=0.04). Serum albumin was significantly higher in the efonidipine period than the amlodipine period (4.0+/-0.5 vs. 3.8+/-0.5 mEq/L, p=0.03). Glomerular filtration rate was not significantly different between the two periods. Plasma aldosterone was lower in the efonidipine period than in the amlodipine period (52+/-46 vs. 72+/-48 pg/mL, p=0.009). It may be concluded that efonidipine results in a greater reduction of plasma aldosterone and proteinuria than amlodipine, and that these effects occur by a mechanism independent of blood pressure reduction. A further large-scale clinical trial will be needed in order to apply the findings of this study to the treatment of patients with renal disease.

Gastric perforation during endoscopic resection for gastric carcinoma and the risk of peritoneal dissemination

BACKGROUND

The potential risk of peritoneal seeding following perforation caused by endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) is unknown.

METHODS

Between January 1991 and December 2003, 90 patients suffered gastric perforation during EMR or ESD at the National Cancer Centre Hospital, Tokyo. The clinical and pathological evidence for peritoneal dissemination in these patients was assessed retrospectively.

RESULTS

Eighty-four patients were followed up at this hospital for a median of 53.6 (range 7.0-136.6) months; the remaining six patients were followed up at other institutions. In 83 patients the perforation was repaired by endoscopic clip application and seven patients underwent emergency surgery. Gastrectomy was carried out in 33 patients who had non-curative endoscopic surgery. Among these, peritoneal fluid was sampled during operation in nine patients and was cytologically negative for malignancy. The other 24 patients who had a gastrectomy did not have ascites so cytology was not performed. No peritoneal dissemination was noted during follow-up.

CONCLUSION

This study suggests that perforation associated with EMR and ESD does not lead to peritoneal dissemination even in the long term.

Inhibition of Rho-kinase attenuates nephrosclerosis and improves survival in salt-loaded spontaneously hypertensive stroke-prone rats

OBJECTIVES

We examined whether the Rho/Rho-kinase pathway is involved in the pathogenesis of nephrosclerosis in severely hypertensive rats and assessed the effects of long-term treatment with a Rho-kinase inhibitor, fasudil, on kidney function, histological findings, gene expressions, and survival. We also attempted to elucidate the mechanisms involved.

METHODS

We studied the following four groups: control Wistar-Kyoto rats (WKY), untreated salt-loaded spontaneously hypertensive stroke-prone rats (SHR-SP), low-dose fasudil (15 mg/kg per day)-treated SHR-SP, and high-dose fasudil (30 mg/kg per day)-treated SHR-SP. After 8 weeks' treatment, the effects of fasudil were examined.

RESULTS

Untreated SHR-SP were characterized by increased blood pressure without circadian variation, decreased kidney function, abnormal renal morphological findings, and increased messenger RNA expression levels of transforming growth factor beta, collagen I, collagen III, p40phox, p47phox, plasminogen activator inhibitor 1, and intracellular adhesion molecule 1 in the renal cortex, compared with WKY. Long-term high-dose fasudil treatment significantly improved renal function (serum creatinine -32%, creatine clearance +39%), proteinuria (-92%) and histological findings (glomerular injury score -57%, arteriolar injury score -55%, fibrous area -40%, ED-1-positive cells -43%) without changing blood pressure or circadian variation, compared with untreated SHR-SP. In addition, fasudil significantly improved increased mRNA expression levels in the renal cortex. Furthermore, high-dose fasudil significantly prolonged survival time compared with untreated SHR-SP (P < 0.01). Low-dose fasudil treatment improved these variables slightly, but did not affect most significantly.

CONCLUSION

The Rho/Rho-kinase pathway participates in the pathogenesis of nephrosclerosis in SHR-SP independently of blood pressure-lowering activity, partly by upregulation of the gene expressions of extracellular matrix, oxidative stress, adhesion molecules, and antifibrinolysis.

Benazepril slows progression of renal dysfunction in patients with non-diabetic renal disease

AIM

The present study examined the effects of benazepril, an angiotensin-converting enzyme inhibitor, on the progression of renal insufficiency in patients with non-diabetic renal disease.

METHODS

Fifteen patients with non-diabetic renal disease whose serum creatinine (Cr) ranged from 1.5 to 3.0 mg/dL were given either benazepril (2.5-5 mg) or placebo once daily for 1 year in a random crossover manner. In both periods, antihypertensive medications were increased if blood pressure was greater than 130/85 mmHg. Blood sampling and urinalysis were performed bimonthly throughout the study period.

RESULTS

Blood pressure was similar when comparing the benazepril and the placebo periods (128+/-12/83+/-6 vs 129+/-10/83+/-7 mmHg). Serum Cr significantly increased from 1.62+/-0.18 to 1.72+/-0.30 mg/dL (P=0.036) during the placebo period, while there was no statistically significant increase in serum Cr during the benazepril period (from 1.67+/-0.17 to 1.71+/-0.27 mg/dL). The slope of decrease of the reciprocal of serum Cr was steeper in the placebo period than in the benazepril period (-0.073+/-0.067 vs-0.025+/-0.096/year, P=0.014). Urinary protein excretion was lower during the benazepril period than during the placebo period (0.57+/-0.60 vs 1.00+/-0.85 g/gCr, P=0.006). Serum K was significantly higher in the benazepril period than in the placebo period (4.4+/-0.5 vs 4.2+/-0.5 mEq/L, P<0.001), but no patient discontinued benazepril therapy as a result of hyperkalemia.

CONCLUSION

Long-term benazepril treatment decreased the progression of renal dysfunction in patients with non-diabetic renal disease by a mechanism that is independent of blood pressure reduction.

Rapid-prototyped temporal bone and inner-ear models replicated by adjusting computed tomography thresholds

Purpose:

This study aimed to investigate the validity of adjusting computed tomography thresholds in order to replicate a temporal bone model suitable for dissection training and education.

Materials and methods:

A simulated three-dimensional model of a human temporal bone was prototyped using selective laser sintering. The powder layers were laser-fused, based on detailed computed tomography data, and accumulated to create a three-dimensional structure. The computed tomography threshold value of the stapes was modified on standard triangular language file in order to replicate the stapes. The intensity value was determined to select the fluid lumen of the inner ear and the bone surface, in order to replicate the inner ear.

Results:

The model could be shaved, using surgical instruments, in the same manner as during real surgery. The stapes could be reproduced, making this model even more realistic than a previous version. The inner ear was recreated, along with the surrounding bony wall and the ossicles.

Conclusion:

This model facilitates dissection training and easy understanding of the relation between the labyrinth and the surrounding structures.

Apparent motion of monocular stimuli in different depth planes with lateral head movements

A stationary monocular stimulus appears to move concomitantly with lateral head movements when it is embedded in a stereogram representing two front-facing rectangular areas, one above the other at two different distances. In Experiment 1, we found that the extent of perceived motion of the monocular stimulus covaried with the amplitude of head movement and the disparity between the two rectangular areas (composed of random dots). In Experiment 2, we found that the extent of perceived motion of the monocular stimulus was reduced compared to that in Experiment 1 when the rectangular areas were defined only by an outline rather than by random dots. These results are discussed using the hypothesis that a monocular stimulus takes on features of the binocular surface area in which it is embedded and is perceived as though it were treated as a binocular stimulus with regards to its visual direction and visual depth.

The synthetic TRH analogue taltirelin exerts modality-specific antinociceptive effects via distinct descending monoaminergic systems

BACKGROUND AND PURPOSE

Exogenously administered thyrotropin-releasing hormone (TRH) is known to exert potent but short-acting centrally-mediated antinociceptive effects. We sought to investigate the mechanisms underlying these effects using the synthetic TRH analogue taltirelin, focusing on the descending monoaminergic systems in mice.

EXPERIMENTAL APPROACH

The mice received systemic or local injections of taltirelin combined with either central noradrenaline (NA) or 5-hydroxytryptamine (5-HT) depletion by 6-hydroxydopamine (6-OHDA) or DL-p-chlorophenylalanine (PCPA), respectively, or blockade of their receptors. The degree of antinociception was determined using the tail flick and tail pressure tests.

KEY RESULTS

Subcutaneously (s.c.) administered taltirelin exhibited dose-dependent antinociceptive effects in the tail flick and tail pressure tests. These effects appeared to be primarily supraspinally mediated, since intracerebroventricularly (i.c.v.) but not intrathecally (i.t.) injected taltirelin generated similar effects. Depletion of central NA abolished only the analgesic effect of taltirelin (s.c. and i.c.v.) on mechanical nociception. By contrast, depletion of central 5-HT abolished only its analgesic effect on thermal nociception. Intraperitoneal (i.p.) and i.t. injection of the alpha2-adrenoceptor antagonist yohimbine respectively reduced the analgesic effect of taltirelin (s.c. and i.c.v.) on mechanical nociception. By contrast, the 5-HT1A receptor antagonist WAY-100635 (i.p. and i.t.) reduced the effect of taltirelin (s.c. and i.c.v.) on thermal nociception. Neither the 5-HT2 receptor antagonist ketanserin nor the opioid receptor antagonist naloxone altered the antinociceptive effect of taltirelin.

CONCLUSIONS AND IMPLICATIONS

These findings suggest that taltirelin activates the descending noradrenergic and serotonergic pain inhibitory systems, respectively, to exert its analgesic effects on mechanical and thermal nociception.

Cardiorenal protective effects of year-long antihypertensive therapy with an angiotensin-converting enzyme inhibitor or a calcium channel blocker in spontaneously hypertensive rats

BACKGROUND

The objective of this study was to evaluate the effect of year-long antihypertensive therapy with a calcium channel blocker and an angiotensin-converting enzyme (ACE) inhibitor on cardiac and renal injury.

METHODS

Male 15-week-old spontaneously hypertensive rats (SHR) were given either a normal diet and normal drinking water (n = 10), a diet containing 0.05% nitrendipine (n = 10), or drinking water containing 50 mg/L of quinapril (n = 10). After 12 months of antihypertensive treatment, cardiovascular organ injuries were evaluated.

RESULTS

Tail-cuff blood pressure (BP) at 12 months was significantly lower in animals receiving nitrendipine or quinapril than in control animals (control, 231 +/- 2 mm Hg; nitrendipine, 194 +/- 3 mm Hg; quinapril, 191 +/- 3 mm Hg; P < .001). Furthermore, aortic thickness was reduced by nitrendipine (-19%, P < .001) or quinapril (-21%, P < .001), and cardiac ventricular weight was significantly reduced by quinapril (-18%, P < .001) but not by nitrendipine (-5%, P = not significant [NS]). Echocardiography at 12 months revealed that midwall fractional shortening was higher in the quinapril group than in the control or the nitrendipine groups (control, 9.3% +/- 0.5%; nitrendipine, 9.8% +/- 0.5%; quinapril, 10.6% +/- 0.6%; P < .05). Left ventricular hydroxyproline levels were lower in the nitrendipine group (-21%, P < .01) and the quinapril group (-36%, P < .001) than in the control animals. In control SHR, creatinine clearance began to decrease and proteinuria began to increase at 6 to 9 months. Quinapril but not nitrendipine attenuated these markers of renal impairment (creatinine clearance at 12 months: control, 4.7 +/- 0.4 mL/min/kg; nitrendipine, 5.0 +/- 0.4 mL/min/kg; quinapril, 6.1 +/- 0.4 mL/min/kg; P < .05). Histologically, the glomerular injury score was lower in the quinapril group than in the control or nitrendipine groups (control, 19 [range, 8 to 30]; nitrendipine, 18 [range, 9 to 32]; quinapril, 7 [range, 3 to 12]; P < .01).

CONCLUSIONS

It is suggested that year-long antihypertensive therapy with an angiotensin-converting enzyme (ACE) inhibitor is superior to a calcium channel blocker in terms of cardiorenal protection in SHR.

Roles of TGF-beta1 and apoptosis in the progression of glomerulosclerosis in human IgA nephropathy

Apoptotic glomerular cells have been detected in the severely damaged glomeruli that are a consequence of human IgA nephropathy. Transforming growth factor-(TGF) beta1 is known to induce apoptosis in cultured mesangial cells. To clarify whether TGF-beta1 contributes to the progression of IgA nephropathy by activating apoptosis in glomerular cells, we examined the expression of TGF-beta1 gene and apoptotic changes in kidney biopsy samples, and assessed those relations to the severity of nephropathy. 32 patients with IgA nephropathy, showing proteinuria (> 1 g/day) and serum creatinine less than 1.5 mg/dl were classified according to glomerular sclerosis index (GSI) into 3 groups (Group I: GSI < 0.3,Group 11: 0.3 < or = GSI < 1.0, Group: III GSI > or = 1.0). Computer-aided morphometry of glomeruli and arteries, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling of fragmented DNA (TUNEL) staining were performed. Expression of TGF-beta1 and caspase-3 mRNAs in renal biopsy samples was analyzed by real-time PCR (Taq Man method). Increased glomerular area, interstitial fibrosis, lymphocytic infiltration, and tubulointerstitial changes were observed to accompany increased severity of GSI. TUNEL index was higher in Group III. The levels of TGF-beta1 and caspase-3 mRNAs were significantly increased in Group III (183 and 190%, respectively). Furthermore, caspase-3 mRNA levels were tightly associated with TGF-beta1 mRNA expression (r = 0.677, p < 0.0001). The present study suggests that the activation of TGF-beta1 plays a role in the progression of IgA nephropathy even in the moderate degree of glomerular injury, in part via activation of apoptosis of glomerular cells.

Upper GI foreign body: an adult urban emergency hospital experience

BACKGROUND

The efficacy of flexible endoscopy by a single endoscopist in the therapy of foreign body ingestion was assessed at an adult urban emergency hospital.

METHODS

Fifty-one adult patients with upper GI foreign body ingestion treated at Detroit Receiving Hospital from 1988 to 2004 were identified. Endoscopic and hospital medical records were reviewed to evaluate etiology, treatment, and outcomes for these patients.

RESULTS

The etiology was related to eating in 38(75%) patients, most of whom were eating meat; phytobezoars were seen in four, often after previous upper GI surgery. True foreign bodies were found in 13 patients (25%) and included a screwdriver, a ballpoint pen, spoons, coat hanger pieces, batteries, and latex gloves. Dysphagia was the most common symptom (75%); pain was common in patients with true foreign bodies, and 62% of this group had psychiatric difficulties or problems with drug abuse. Nearly 80% of the food-related group had post-surgical or other upper GI pathology. One patient had an esophageal stricture secondary to previous Sengstaken-Blakemore tube insertion. Flexible endoscopy was successful in extracting the foreign body in almost all (49) patients, with snare extraction the most common therapeutic modality. Both failures were of true foreign bodies that could not be safely removed. In one of these cases, it became necessary to employ the gallstone lithotripter, and the overtube was required in patients with metallic or sharp foreign bodies to protect the upper aerodigestive structures.

CONCLUSIONS

Most upper GI foreign bodies are related to food impaction, with meat most often found. Underlying pathology is the rule and should be dealt with immediately. Flexible endoscopy is the treatment of choice for upper GI foreign body removal with near perfect success.