Prolonged esophageal acid exposures induce synaptic downscaling of cortical membrane AMPA receptor subunits in rats.

BACKGROUND: We recently reported the involvement of AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor subunit upregulation and phosphorylation in the rostral cingulate cortex (rCC) as the underlying mechanism of acute esophageal acid-induced cortical sensitization. Based on these findings, we proposed to investigate whether prolonged esophageal acid exposures in rats exhibit homeostatic synaptic scaling through downregulation of AMPA receptor expression in rCC neurons. We intended to study further whether this compensatory mechanism is impaired when rats are pre-exposed to repeated esophageal acid exposures neonatally during neuronal development. METHODS: Two different esophageal acid exposure protocols in rats were used. Since AMPA receptor trafficking and channel conductance depend on CaMKIIα-mediated phosphorylation of AMPA receptor subunits, we examined the effect of esophageal acid on CaMKIIα activation and AMPA receptor expression in synaptoneurosomes and membrane preparations from rCCs. KEY RESULTS: In cortical membrane preparations, GluA1 and pGluA1Ser(831) expression were significantly downregulated following prolonged acid exposures in adult rats; this was accompanied by the significant downregulation of cortical membrane pCaMKIIα expression. No change in GluA1 and pGluA1Ser(831) expression was observed in rCC membrane preparations in rats pre-exposed to acid neonatally followed by adult rechallenge. CONCLUSIONS & INFERENCES: This study along with our previous findings suggests that synaptic AMPA receptor subunits expression and phosphorylation may be involved bidirectionally in both esophageal acid-induced neuronal sensitization and acid-dependent homeostatic plasticity in cortical neurons. The impairment of homeostatic compensatory mechanism as observed following early-in-life acid exposure could be the underlying mechanism of heightening cortical sensitization and esophageal hypersensitivity in patients with gastroesophageal reflux disease.

Probiotic Lactobacillus rhamnosus GG (LGG) and prebiotic prevent neonatal inflammation-induced visceral hypersensitivity in adult rats.

BACKGROUND: Increasing evidence indicates a positive effect of probiotics on the nervous system. The objective of this study was to determine if probiotic Lactobacillus rhamnosus GG (LGG) and/or prebiotics polydextrose/galactooligosaccharide (PDX/GOS) can alter the colonic sensitivity in a neonatal rat model of chronic visceral hyperalgesia and to determine whether altered sensitivity is associated with changes in neurotransmitter levels in the brain. METHODS: Chronic visceral hyperalgesia was induced in rats by intracolonic administration of zymosan for 3 days during postnatal day 14-16 (P14-P16). After weaning (P21), these pups were divided into groups that received either (1) control diet (CD), (2) PDX/GOS, (3) LGG, or (4) PDX/GOS + LGG. These diets were continued until visceral sensitivity was tested at P60. The viscero-motor response (VMR) to graded colorectal distension (CRD) was determined by measuring the electromyographic (EMG) activity from the abdominal external oblique muscles. The levels of neurotransmitters and biogenic amines were quantified in the frontal cortex, subcortex, brain stem, and cerebellum. KEY RESULTS: At P60, the VMR to CRD in the neonatal zymosan-treated rats was significantly higher than neonatal saline-treated rats. In contrast, neonatal zymosan-treated rats that received PDX/GOS or LGG did not exhibit visceral hyperalgesia. The levels of serotonin, noradrenaline, and dopamine were significantly altered in LGG-treated rats compared to other groups. CONCLUSIONS & INFERENCES: Results document that in rats LGG can attenuate neonatally induced chronic visceral pain measured in adulthood. Prolonged intake of LGG alters some key brain neurotransmitters and biogenic amines that could be involved in pain modulation.

Expressional regulation of genes linked to immunity & programmed development in human early placental villi.

BACKGROUND & OBJECTIVES: During 6 to 8 wk of gestation, human placental villi show a complex pattern of morphogenesis. There is however, no large scale gene expression study exploring the temporal pattern of the developmental molecular networks in placental villi during the early weeks of gestation. We evaluated the transcriptome profiling of humn placental villus samples obtained from fertile women with voluntarily terminated normal pregnancies between 6-8 wk of gestation. METHODS: Transcriptomic profiles of individual human placental villous samples from 25 women with normal pregnancies during 6 to 8 wk of gestation were examined using human whole genome expression arrays. Quantitative RT-PCR validation of copy numbers of transcripts for selected 15 genes and exploratory analysis of the microarray data revealed a high degree of quality assurance supportive of further clustering and differential analyses. Immunoblot and immunohistochemical analysis of selected five candidate proteins (CAGE1, CD9, SLC6A2, TANK and VEGFC) based on transcript profiles were done to assess the pattern of down stream informational flow. RESULTS: A large number (~9K) of genes with known functions were expressed in the experimental samples. The clustering analysis identified three major expression clusters with gestational age, and four co-expressional clusters. Differential analysis identified a highly discrete regulatory process involving only about 160 genes. Immunochemical analysis of selected candidate proteins based on transcript profiles revealed generally synchronous expression in human early placental villi. INTERPRETATION & CONCLUSIONS: Several signaling pathways linked to immunity (COL1, JAK2, JAK3, IL12, IL13, IL15, IL27, STAT3 and STAT5) were downregulated, while genes of the enriched category of antiviral immunity (ATF/AP1, IL10R and OAS) were clearly over-expressed. Transcriptional integration supportive of programmed development was observed in first trimester placental villi and it included regulation of apoptosis and cell cycle progression (ARRB1, ATR, BLM, CHRNA7, CHRNB1, FYN, KPNA4, and MTOR/FRAP), autophagy (ATG4B, ATG14, BAD, and BCL2), cell adhesion (CD9 and FN1) and epithelial-to-mesenchymal transition (CALD1, FN1, HEY1, MMP2, and WNT3A).

Delineating the prime mover action of progesterone for endometrial receptivity in primates.

Progesterone is essential for endometrial receptivity in primates. It is now evident that embryo-derived signal influences implantation stage endometrium under progesterone dominance, and collectively results in endometrial receptivity to implanting blastocyst. Previously, a few studies were performed using global gene profiling based on microarray technology to identify changes in gene expression between early luteal phase and mid luteal phase endometrium, however, the issue of combinatorial regulation by progesterone-dependent regulation and by embryo-derived signal on transcripts profiles during endometrial differentiation toward receptivity for blastocyst implantation in primates has not been addressed. the present review summarizes a few issues, specifically that of transforming growth factor ß-tumour necrosis factor α (TGFß-TNFα) pathways and signal transducer and activator of transcription (STAT) signalling system related to luteal phase progesterone action on endometrial receptivity in terms of its transcriptomic expression using a potent antiprogestin (mifepristone) in conception cycles of the rhesus monkey as a non-human primate model.

AMPA receptor subunits expression and phosphorylation in cingulate cortex in rats following esophageal acid exposure.

BACKGROUND: We recently reported an increase in N-methyl-d-aspartate (NMDA) receptor subunit expression and CaMKII-dependent phosphorylation of NR2B in the rostral cingulate cortical (rCC) neurons following esophageal acid exposure in rats. As α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors mediate the fast excitatory transmission and play a critical role in synaptic plasticity, in this study, we investigated the effect of esophageal acid exposure in rats on the expression of AMPA receptor subunits and the involvement of these molecular alterations in acid-induced sensitization of neurons in the anterior cingulate (ACC) and midcingulate (MCC) cortices. METHODS: In molecular study, we examined GluA1 and GluA2 expression and phosphorylation in membrane preparations and in the isolated postsynaptic densities (PSDs) from rats receiving acute esophageal exposure of either saline (control group) or 0.1 N HCl (experimental group). In electrophysiological study, the effect of selective AMPA receptor (Ca(2+) permeable) antagonist IEM-1460 and CaMKII inhibitor KN-93 was tested on responses of cortical neurons during acid infusion to address the underlying molecular mechanism of acid-induced sensitization. KEY RESULTS: The acid exposure significantly increased expression of GluA1, pGluA1Ser(831) , and phosphorylated CaMKIIThr(286) , in the cortical membrane preparations. In isolated PSDs, a significant increase in pGluA1Ser(831) was observed in acid-treated rats compared with controls. Microinjection of IEM-1460 or KN-93 near the recording site significantly attenuated acid-induced sensitization of cortical neurons. CONCLUSIONS & INFERENCES: The underlying mechanism of acid-induced cortical sensitization involves upregulation and CaMKII-mediated phosphorylation of GluA1. These molecular changes of AMPA receptors subunit GluA1 in the cortical neurons might play an important role in acid-induced esophageal hypersensitivity.

Pronociceptive effect of 5-HT(1A) receptor agonist on visceral pain involves spinal N-methyl-D-aspartate (NMDA) receptor.

The functional role of serotonergic 5-HT(1A) receptors in the modulation of visceral pain is controversial. The objective of this study was to systematically examine the mechanism and site of action of a selective 5-HT(1A) receptor agonist 8-hydroxy-2-(di-n-propylamino)-tetralin (DPAT) on visceral pain. In the behavioral model of visceral pain, systemic injection (5-250 µg/kg) of DPAT produced a significant increase in the viscero-motor response (VMR) to colorectal distension (CRD) and this effect was blocked by the selective 5-HT(1A) receptor antagonist WAY-100135 (5 mg/kg, s.c.). Similarly, intrathecal (i.t.) injection (5 µmol) of DPAT into the lumbo-sacral (L6-S1) spinal cord produced a significant increase in VMR. The administration of N-methyl D-aspartate (NMDA) receptor antagonist AP5 (50 µg/kg) prior to DPAT injection completely blocked the pronociceptive effect of DPAT. Similarly, DPAT failed to increase VMR in rats chronically treated with NR1 subunit-targeted antisense oligonucleotide (ON), whereas the drug increased VMR in rats treated with mismatched-ON. Chronic i.t. injection of allylglycine (AG), a γ-amino decarboxylase (GAD) enzyme inhibitor, produced significant increase in VMRs, suggesting that the inhibition of GABA synthesis produces pronociception. In AG-treated rats, i.t. injection of DPAT failed to further increase in VMR, suggesting that the DPAT action is linked to GABA release. Similarly, WAY-100135 failed to attenuate VMR in AG-treated rats, suggesting that unlike DPAT, AG action is not via the activation of 5-HT(1A) receptors. In electrophysiology experiments, DPAT (50 µg/kg) significantly increased the responses of spinal neurons to CRD, but did not influence the mechanotransduction property of CRD-sensitive pelvic nerve afferent fibers. The effect of DPAT on spinal neurons remained unaffected when tested in spinal-transected (C1-C2) rats. These results indicate that the 5-HT(1A) receptor agonist DPAT produces pronociceptive effects, primarily via the activation of presynaptic 5-HT(1A) receptors in GABAergic neuron to restrict GABA release and thereby disinhibits the excitatory glutamatergic neurons in the spinal cord.

Colonic butyrate- algesic or analgesic?

Irritable bowel syndrome (IBS) is a common health issue that is characterized by abdominal pain, abnormal bowel movements, and altered visceral perception. The complexity and variability in symptoms pose serious challenges in treating IBS. Current therapy for IBS is primarily focused on reducing the abdominal pain, thereby improving the quality of life to a significant extent. Although the use of fiber rich diet is widely recommended in treating IBS, some studies have questioned its use. Intra-colonic butyrate, a short-chain fatty acid, is primarily produced by the fermentation of dietary fibers in the colon. In the existing literature there are conflicting reports about the function of butyrate. In rats it is known to induce visceral hypersensitivity without altered pathology, whereas in humans it has been reported to reduce visceral pain. Understanding the molecular mechanisms responsible for this contrasting effect of butyrate is important before recommending fiber rich diet to IBS patients.

Neonatal cystitis-induced colonic hypersensitivity in adult rats: a model of viscero-visceral convergence.

BACKGROUND: The objective of this study was to determine if neonatal cystitis alters colonic sensitivity later in life and to investigate the role of peripheral mechanisms. METHODS: Neonatal rats received intravesical zymosan, normal saline, or anesthesia only for three consecutive days [(postnatal (PN) days 14-16)]. The estrous cycle phase was determined prior to recording the visceromotor response (VMR) to colorectal distension (CRD) in adult rats. Eosinophils and mast cells were examined from colon and bladder tissues. CRD- or urinary bladder distension (UBD)-sensitive pelvic nerve afferents (PNAs) were identified and their responses to distension were examined. The relative expression of N-methyl-d-aspartic acid (NMDA)-NR1 subunit in the lumbo-sacral (L6-S1) spinal cord was examined using Western blot. KEY RESULTS: The VMR to CRD (≥10mmHg) in the neonatal zymosan group was significantly higher than control in both the diestrus, estrus phase and in all phases combined. There was no difference in the total number of eosinophils, mast cells or number of degranulated mast cells between groups. The spontaneous firing of UBD, but not CRD-sensitive PNAs from the zymosan-treated rats was significantly higher than the saline-treated control. However, the mechanosensitive properties of PNAs to CRD or UBD were no different between groups (P>0.05). The expression of spinal NR1 subunit was significantly higher in zymosan-treated rats compared with saline-treated rats (P<0.05). CONCLUSIONS & INFERENCES: Neonatal cystitis results in colonic hypersensitivity in adult rats without changing tissue histology or the mechanosensitive properties of CRD-sensitive PNAs. Neonatal cystitis does result in overexpression of spinal NR1 subunit in adult rats.

IGF2, IGF binding protein 1, and matrix metalloproteinases 2 and 9 in implantation-stage endometrium following immunoneutralization of vascular endothelial growth factor in the rhesus monkey.

Blastocyst implantation in the rhesus monkey is inhibited by administration of antibody against vascular endothelial growth factor (VEGF) A during peri-implantation period with no change in the circulatory concentrations of estradiol, progesterone, and VEGF. In this study, we have investigated the effect of administration of a MAB to VEGFA on days 5 and 10 after ovulation upon the mRNA expression, immunopositive protein expression, and immunohistological localization of IGF2, IGF binding protein 1 (IGFBP1) and matrix metalloproteinases (MMPs) 2 and 9 in the implantation-stage endometrium collected on day 13 after ovulation from fecund cycles of rhesus monkeys. The comparison between isotype-matched IgG (control; n=8)- and VEGF antibody (VEGF Mab; n=8)-treated animals revealed higher (P<0.05) IGF2 in lacunar and villous syncytiotrophoblasts, trophoblast cell columns, migrating extravillous trophoblast cells, and endovascular trophoblast cells in control animals, but with no change in the various cell types of maternal endometrium between the two groups. No change in IGFBP1 expression in the endometrium was observed between the two groups. MMPs 2 and 9 were detected in syncytiotrophoblast in lacunae and villi, trophoblast cell columns, and extravillous trophoblast cells in control samples. MMP9 transcript expression in maternal endometrium and its immunopositivity in endometrial stroma and trophoblast cells were lower (P<0.05) with no change in MMP2 level in VEGF Mab-exposed samples compared with those in control samples. A functional network involving VEGF, IGF2, and MMP9 in early placental trophoblast cells and maternal endometrium appears to be important for normal placentation.

Synthesis of beta-SiC/SiO2 core-sheath nanowires by CVD technique using Ni as catalyst.

Cubic silicon carbide (beta-SiC)/SiO2 nanowires with uniform and knotted-core structures have been synthesized on nickel-coated Si(111) substrates at 1150 degrees C by using hexamethyldisilane (HMDS) as the source material in a hot wall atmospheric pressure chemical vapor deposition (APCVD) system. The nanowires consist of a single crystalline beta-SiC core wrapped with an amorphous SiO2 shell. The as-prepared SiC nanowires and the deposited Ni films were characterized by field emission scanning electron microscopy, X-ray diffraction, high resolution transmission electron microscopy, energy dispersive X-ray spectroscopy, micro-Raman spectroscopy, infrared spectroscopy and atomic force microscopy. The results show that the nanowires are random in direction and have diameter ranges from 25 nm to 70 nm. The core of the nanowires has a cubic zinc blend structure and a high density of planar defects is often found. The twin plane defects are suspected to be the main reason for the formation of the knotted-core SiC nanowires. A possible growth mechanism based on vapor-liquid-solid (VLS) by base growth technique is proposed.

Small scale transcript expression profile of Human first trimester placental villi analyzed by a custom-tailored cDNA array.

Human placental trophoblastic mass grows rapidly between 4 and 8 weeks of gestation making it highly vulnerable to external and internal challenges, however, there has been no reported study exploring the developmental molecular characteristics in human first trimester placental villi. In the present study, transcript expressions of human placental villi of normal pregnancies during 6 (n=6), 7 (n=6) and 8 (n=6) weeks of gestation using custom-tailored cDNA-based expression arrays for -400 annotated human gene products were examined. Unsupervised and supervised analyses of expression data revealed that 386 (95%) genes were overtly involved in the first trimester placental villi, and these genes segregated into three clusters specifically corresponding to 6-, 7- and 8-weeks of gestation in principal component analysis. Bayesian prediction analysis based on relative expression levels of genes studied identified that expression patterns in 15 samples out of 18 samples showed concordance with high (0.8-1.0) confidence measures with the chronological age of the placenta, however, two samples collected during 7-weeks of gestation and one sample collected during 8-weeks of gestation were predicted to be 6-weeks sample with confidence measures between 0.6 and 0.5. Unsupervised hierarchical clustering analysis segregated the samples into two major branches; while one of them was composed of five 7-weeks samples only, the second major branch had three sub-branches: one of them was exclusively composed of three 8-week samples only, while other two sub-branches were mainly composed of 6-weeks samples. K-means clustering analysis identified four optimal clusters of genes depending on the similarity of their relative expression for the set of genes studied across all the samples. Gene ontology (GO) based functional classifications of genes in K-means clusters revealed that the overall putative functions of co-regulated gene clusters were mutually comparable, however, specific genes related to ion homeostasis, metabolism, and VEGF activity specifically clustered in 8-weeks samples. Analysis of relative gene expression during in 6-8 week placental villi revealed that a large number of gene products were over represented by their either up-regulation (70 genes: approximately 18%) or down regulation (53 genes; approximately 14%) between 6 and 8 weeks villi samples and these genes are reportedly involved in biological processes like regulation of cell growth and proliferation, anti-apoptosis, angiogenesis, immune and inflammatory responses, extracellular matrix remodeling and multicellular organismal development involving almost all cellular components and molecular functions like signal transduction activity, transcription factor activity, nucleotide and protein binding, ion (especially calcium and zinc) binding and growth receptor activities. Interestingly, four genes (oxytocin receptor, tenascin C, TNF-R1 and retinol binding protein 1) showed differential regulation in human placental villi during 6-8 weeks of gestation, suggestive of an underlying network of regulation involving these factors in the developing placenta. To our knowledge, this is the first report indicating that these genes are involved in the early stage development of human placenta.

Quantitative analysis of six gene products as candidate markers of early placental villi development in the human.

Early placental development is critical for successful pregnancy. Recently, we have reported that -70 genes were differentially expressed in human placental villi between 6- and 8- weeks of gestation in cDNA-based expression arrays for -400 PCR products, of which six specific gene products (COL4A4, CXCR4, ERBB2, HDAC1, HPRT1, and TNFRSF1A) appeared intriguing. In the present study we have examined expressions of these six candidate genes in placental villi obtained from 6-weeks, 7-weeks and 8-weeks (n = 6 for each group) human placental samples using quantitative real time RTPCR. We observed that there was considerable concordance (>95% confidence) in pair-wise analysis of transcript profiles between the two methods, however, absolute quantitative values as measured by quantitative RTPCR differed from those obtained from cDNA-based array analysis for 2 gene products (CXCR4 and ERBB2) out of 6 genes. No significant change was observed in the steady state expression of COL4A4 and HPRT1 during the time period examined. However, there was significant decrease in CXCR4 for 7-weeks (P < 0.01) and 8-weeks (P < 0.05) samples, and significant (P < 0.05) increase was seen for ERBB2 in 7-weeks and 8-weeks as compared to 6-weeks samples with no change between 7-weeks and 8-weeks samples. Moreover, significant (P < 0.05) increase for HDAC1 and decrease for TNFRSF1A was observed in 8-weeks samples as compared to 6-weeks samples with no change observed between 6-weeks and 7-weeks samples. We infer that it is essential that cDNA array-based data are verified in terms of quantitative estimates preferably by quantitative PCR before their use for any exploratory purpose. Taking together our previous array based data and the present study we conclude that a categorical balance exists between the expression of ERBB2 and HDAC1 genes affecting cell proliferation and differentiation in one hand, and CXCR4 and TNFRSF1A affecting chemotaxis, inflammatory response and apoptosis on the other hand. The expression of these genes appear important for the early development of human placental villi.

Altered mechanosensitive properties of vagal afferent fibers innervating the stomach following gastric surgery in rats.

BACKGROUND AND AIMS: Several types of gastric surgeries have been associated with early satiety, dyspepsia and food intolerances. We aimed to examine alterations in gastric vagal afferents following gastric surgery-fundus ligation. METHODS: Six week old, male Sprague-Dawley rats underwent chronic ligation (CL) of the fundus. Sham rats underwent abdominal surgery, but without ligation. Another group of rats underwent acute ligation (AL) of the fundus immediately prior to experiments. CL and sham rats were allowed to grow to age 3-4 months. Food intake and weights were recorded post-operatively. Gastric compliance and gastric wall thickness was measured at baseline and during gastric distension (GD). Extracellular recordings were made to examine response characteristics of vagal afferent fibers to GD and to map the stomach receptive field (RF). The morphological structures of afferent terminals in the stomach were examined with retrograde tracings from the nodose ganglion. RESULTS: The CL group consumed significantly less food and weighed less than sham control. The mean compliance of the CL group was significantly less than control, but higher than the AL group. The spontaneous firing and responses to GD of afferent fibers from the CL rats were significantly higher than AL rats. There was a marked expansion of the gastric RF in the CL rats with significant reorganization and regeneration of intramuscular array (IMA) terminals. There was no difference in total wall or muscle thickness among the groups. CONCLUSION: CL results in aberrant remodeling of IMAs with expansion of the gastric RF and alters the mechanotransduction properties of vagal afferent fibers. These changes could contribute to altered sensitivity following gastric surgery.

Differential effects of transient receptor vanilloid one (TRPV1) antagonists in acid-induced excitation of esophageal vagal afferent fibers of rats.

Gastro-esophageal acid reflux can stimulate esophageal vagal sensory afferents by activating proton-sensitive ion channel transient receptor vanilloid one (TRPV1). The objective of this study was to investigate the response characteristics of vagal afferent fibers of rats to acid (0.1 N HCl) and capsaicin (CAP) following esophagitis and differential effects of two classes of TRPV1 antagonists on responses of vagal afferent fibers. The chronic reflux was induced by ligating the fundus of the stomach and partial constriction of pylorus. Extracellular single fiber recordings were made from the cervical vagal afferent fibers from naive control and fundus-ligated (FL) esophagitis rats. Innervations of fibers were identified to esophageal distension (ED) and subsequently tested to CAP and acid before and after injection of TRPV1 antagonist JYL1421 or AMG9810 (10 micromol/kg i.v.). Seventy-five vagal afferent fibers from 70 rats were identified to ED. Intra-esophageal CAP (0.1 ml of 1 mg/ml) excited 39.5% (17/43, 5/22 from naive and 12/21 from FL rats) fibers. In contrast, i.v. injection of CAP (0.03-0.3 micromol/kg) dose-dependently excited 72% (42/58) fibers. Responses to CAP were significantly greater for fibers from FL rats (n=32) than naive rats (n=25). TRPV1 antagonists JYL1421 and AMG9810 (10 micromol/kg) significantly blocked response to CAP. Intra-esophageal acid infusion stimulated 5/17 (29.4%) fibers from naive rats and 12/28 (42%) from FL rats. Effect of acid was significantly blocked by AMG9810, but not by JYL1421. Results indicate that following esophagitis the number of fibers responsive to CAP and acid is greater than noninflamed esophagus, which may contribute to esophageal hypersensitivity. Acid-induced excitation of vagal sensory afferents can be differentially attenuated by different classes of TRPV1 antagonists. Therefore, TRPV1 antagonists play a key role in attenuation of hypersensitivity following reflux-induced esophagitis. The use of TRPV1 antagonists could be an alternative to the traditional symptoms-based treatment of chronic acid reflux and esophageal hypersensitivity.

Modifications to Increase Efficiency of the Begg Orthodontic Technique.

BACKGROUND: Orthodontic appliances that deliver results in a shorter time period without sacrificing the quality of the outcome are preferred. A modified fixed appliance, blending the merits of the Preadjusted Edgewise and Begg appliances was tested. METHODS: Thirty patients each were randomly assigned for treatment with one of the three fixed appliance techniques after qualifying for the inclusion and exclusion criteria established before the study. Peer assessment rating (PAR) index was used to compare the quality of treated cases. Total time as well as chairside time taken for treatment with the three techniques was also compared. ANOVA and paired student 't' test were used for statistical analysis. RESULT: There was a significant reduction in PAR scores with all the three appliances. There was no significant difference in the quality of treatment outcome between the Preadjusted Edgewise appliance (PEA) and the modified Begg appliance. These appliances gave a significantly better improvement as compared to the Begg appliance. Chairside and total time taken was the least with the modified Begg appliance followed by the PEA and Begg appliances. CONCLUSION: The suggested modification of the Begg appliance is efficient and economical as compared to PEA and Begg appliances in the treatment of cases with anterior teeth proclination as one of the elements of malocclusion.

The role of transient receptor potential vanilloid 1 in mechanical and chemical visceral hyperalgesia following experimental colitis.

The transient receptor potential vanilloid 1 receptor (TRPV1) is an important nociceptor involved in neurogenic inflammation. We aimed to examine the role of TRPV1 in experimental colitis and in the development of visceral hypersensitivity to mechanical and chemical stimulation. Male Sprague-Dawley rats received a single dose of trinitrobenzenesulfonic acid (TNBS) in the distal colon. In the preemptive group, rats received the TRPV1 receptor antagonist JYL1421 (10 mumol/kg, i.v.) or vehicle 15 min prior to TNBS followed by daily doses for 7 days. In the post-inflammation group, rats received JYL1421 daily for 7 days starting on day 7 following TNBS. The visceromotor response (VMR) to colorectal distension (CRD), intraluminal capsaicin, capsaicin vehicle (pH 6.7) or acidic saline (pH 5.0) was assessed in all groups and compared with controls and naïve rats. Colon inflammation was evaluated with H&E staining and myeloperoxidase (MPO) activity. TRPV1 immunoreactivity was assessed in the thoraco-lumbar (TL) and lumbo-sacral (LS) dorsal root ganglia (DRG) neurons. In the preemptive vehicle group, TNBS resulted in a significant increase in the VMR to CRD, intraluminal capsaicin and acidic saline compared the JYL1421-treated group (P<0.05). Absence of microscopic colitis and significantly reduced MPO activity was also evident compared with vehicle-treated rats (P<0.05). TRPV1 immunoreactivity in the TL (69.1+/-4.6%) and LS (66.4+/-4.2%) DRG in vehicle-treated rats was increased following TNBS but significantly lower in the preemptive JYL1421-treated group (28.6+/-3.9 and 32.3+/-2.3 respectively, P<0.05). JYL1421 in the post-inflammation group improved microscopic colitis and significantly decreased the VMR to CRD compared with vehicle (P<0.05, >/=30 mm Hg) but had no effect on the VMR to chemical stimulation. TRPV1 immunoreactivity in the TL and LS DRG was no different from vehicle or naïve controls. These results suggest an important role for TRPV1 channel in the development of inflammation and subsequent mechanical and chemical visceral hyperalgesia.

Immunoneutralization of vascular endothelial growth factor inhibits pregnancy establishment in the rhesus monkey (Macaca mulatta).

Maternal endometrial vascular endothelial growth factor (VEGF) is considered important in blastocyst implantation. However, there is no direct evidence to support this conjecture in the primate. In the present study, we have examined this hypothesis by testing whether immunoneutralization of VEGF during the peri-implantation stage of gestation affects embryo implantation in the rhesus monkey. Adult female animals (n = 36) during mated ovulatory cycles were randomly assigned to one of the experimental groups treated subcutaneously with either isotype-matched mouse immunoglobulin (group 1: control, n = 8) or monoclonal mouse antibody against VEGF-A (anti-VEGF Mab; group 2: 10 mg on day 5 after ovulation, n = 8; group 3: 20 mg on day 5 after ovulation, n = 8; group 4: 10 mg on day 10 after ovulation, n = 4; group 5: 10 mg on days 5 and 10 after ovulation, n = 8). Anti-VEGF Mab-treated animals in groups 2-4 did not show any marked inhibition in pregnancy establishment. On pooled analysis, however, anti-VEGF Mab administration in groups 2-5 (n = 28) resulted in a significant (P < 0.04) decline in the number of viable term pregnancy when compared with control animals. The observed difference was explained by the fact that 10 mg anti-VEGF Mab given to each animal on days 5 and 10 after ovulation in group 5 (n = 8) inhibited pregnancy establishment significantly (P < 0.02) when compared with control group 1. There was no significant change in serum concentrations of estradiol-17beta, progesterone, and free VEGF among groups. Furthermore, animals treated with anti-VEGF Mab (n = 8) as in group 5 revealed marked decrease in immunoreactive VEGF, fms-like tyrosine kinase-1, and kinase-insert domain region in trophoblast cells associated with shallow uterine invasion on day 13 of gestation when compared with samples from control group animals (n = 8). Thus, VEGF action is required for successful blastocyst implantation in the rhesus monkey.

Effect of reflux-induced inflammation on transient receptor potential vanilloid one (TRPV1) expression in primary sensory neurons innervating the oesophagus of rats.

A possible mechanism of oesophageal hypersensitivity is the acid-induced activation of transient receptor potential vanilloid receptor 1 (TRPV1) in the primary sensory neurons. We investigated TRPV1 expression and its colocalization with substance P (SP) and isolectin B4 (IB4)-positive cells in the thoracic dorsal root ganglia (DRGs) and nodose ganglia (NGs) of rats with reflux-induced oesophagitis (RO). RO was developed by fundus ligation and partial obstruction of the pylorus of Sprague-Dawley rats. Four groups of rats were used; fundus ligated acute (RO 48 h), chronic 7 days (RO 7D), RO 7D + omeprazole (7D + Omz, 40 mg kg(-1), i.p.) and sham-operated controls. Immunohistochemical analysis of TRPV1, SP and IB4 expression were carried out in spinal cord (SC), DRGs and NGs. RO rats exhibited significant inflammation and increase in TRPV1-ir and SP-ir expressions in the SC, DRGs and NGs. The maximum colocalization of TRPV1 and SP was observed in RO 7D rats, but Omz prevented inflammation and over expression of TRPV1 and SP. TRPV1-ir significantly increased in IB4-positive cells in DRGs and SC, but not in the NGs. Results document that acid-induced oesophagitis increases TRPV1 expression in both SP- and IB4-positive sensory neurons. The over expression of TRPV1 may contribute to oesophageal hypersensitivity observed in gastro-oesophageal reflux disease (GORD).

Neonatal gastric suctioning results in chronic visceral and somatic hyperalgesia: role of corticotropin releasing factor.

Abstract Gastric suctioning is common in neonatal intensive care units. Studies suggest that gastric suctioning in premature infants may play a role in the development of visceral hyperalgesia. We hypothesized that repeated orogastric suctioning during the neonatal period results in chronic alterations in visceral and somatic sensation through a corticotropin-releasing factor mediated mechanism. Neonatal male Long Evans rats (n = 13) received daily orogastric suctioning for 10 days starting at postnatal day two (P2). Control rats (n = 15) were handled similarly without orogastric suction. A second study group was subjected to a similar protocol, only with pre-emptive administration of a CRF1 receptor antagonist (antalarmin, 20 mg/kg, IP) (n = 8). The control group received vehicle only (n = 8). An additional group was given antalarmin without suctioning (n = 5). After these rats grew to adulthood (PN 60), a visceromotor response to graded colorectal distension was recorded (10-80 mmHg, 30s, 180s inter-stimulus intervals) to assess changes in visceral sensitivity. Paw withdrawal latency to noxious heat applied to the hind paws was measured to assess changes in cutaneous sensitivity. Orogastric suctioning during the neonatal period results in global chronic somatic and visceral hyperalgesia in adult rats. Visceral hyperalgesia is prevented by pre-emptive administration of the CRF1 receptor antagonist, antalarmin.

Response properties of the brainstem neurons of the cat following intra-esophageal acid-pepsin infusion.

Studies in humans have documented that acute acid infusion into the esophagus leads to decrease in threshold for sensations to mechanical distension of the esophagus. It is not known whether acid infusion leads to sensitization of brainstem neurons receiving synaptic input from vagal afferent fibers innervating the esophagus. The aim of this study was to investigate the correlation of responses of vagal afferents and brainstem neurons after acute infusion of acid (0.1 N HCl)+pepsin (1 mg/ml) into the esophagus of cats. The vagal afferent fibers (n=20) exhibited pressure-dependent increase in firing to graded esophageal distension (5-80 mm Hg). Infusion of acid+pepsin into the esophagus produced a significant increase in ongoing resting firing of five of 16 fibers (31%) tested. However, their responses to graded esophageal distension did not change when tested 30 min after infusion. Pepsin infusion did not change the resting firing and response to esophageal distension (n=4). Twenty-one brainstem neurons were recorded that responded in an intensity-dependent manner to graded esophageal distension. Responses of 12 excited neurons were tested after intra-esophageal acid+pepsin infusion. Neurons exhibited a decrease in threshold for response to esophageal distension and increase in firing after acid+pepsin infusion. The sensitization of response after intra-esophageal acid remained unaffected after cervical (C1-C2) spinal transection (n=3). Results indicate that the esophageal distension-sensitive neurons in the brainstem exhibit sensitization of response to esophageal distension after acute acid+pepsin exposure. The sensitization of brainstem neurons is possibly initiated by increased spontaneous firing of the vagal afferent fibers to acid+pepsin, but not to sensitized response of vagal distension-sensitive afferent fibers to esophageal distension. Results also indicate that spinal pathway does not contribute to sensitization of brainstem neurons.