Compressive stress induces collective migration through cytoskeletal remodelling in nasal polyp epithelium

BACKGROUND

Nasal polyps in the nasal cavity and mucous discharge inside the maxillary sinus exhibit compressive stress on the nasal mucosal epithelium. However, there have been only a few studies on how compressive stress impacts the human nasal mucosal epithelium.

METHODOLOGY

We investigated the effect of compressive stress on collective migration, junctional proteins, transepithelial electri- cal resistance, epithelial permeability, and gene expression in well-differentiated normal human nasal epithelial (NHNE) cells and human nasal polyp epithelial (HNPE) cells.

RESULTS

NHNE cells barely showed collective migration at compressive stress up to 150 mmH20. However, HNPE cells showed much greater degree of collective migration at a lower compressive stress of 100 mmH20. The cell migration of HNPE cells sub- jected to 100 mmH2O compression was significantly decreased at day 3 and was recovered to the status prior to the compressive stress by day 7, indicating that HNPE cells are relatively more sensitive to mechanical pressure than NHNE cells. Compressive stress also increased transepithelial electrical resistance and decreased epithelial permeability, indicating that the compressive stress disturbed the structural organization rather than physical interactions between cells. In addition, we found that compressive stress induced gene expressions relevant to airway inflammation and tissue remodelling in HNPE cells.

CONCLUSION

Taken together, these findings demonstrate that compressive stress on nasal polyp epithelium is capable of inducing collective migration and induce increased expression of genes related to airway inflammation, innate immunity, and polyp remo- delling, even in the absence of inflammatory mediators.

Transcriptome analysis of air-breathing land slug, Incilaria fruhstorferi reveals functional insights into growth, immunity, and reproduction

Background

Incilaria (= Meghimatium) fruhstorferi is an air-breathing land slug found in restricted habitats of Japan, Taiwan and selected provinces of South Korea (Jeju, Chuncheon, Busan, and Deokjeokdo). The species is on a decline due to depletion of forest cover, predation by natural enemies, and collection. To facilitate the conservation of the species, it is important to decide on a number of traits related to growth, immunity and reproduction addressing fitness advantage of the species.

Results

The visceral mass transcriptome of I. fruhstorferi was enabled using the Illumina HiSeq 4000 sequencing platform. According to BUSCO (Benchmarking Universal Single-Copy Orthologs) method, the transcriptome was considered complete with 91.8% of ortholog genes present (Single: 70.7%; Duplicated: 21.1%). A total of 96.79% of the raw read sequences were processed as clean reads. TransDecoder identified 197,271 contigs that contained candidate-coding regions. Of a total of 50,230 unigenes, 34,470 (68.62% of the total unigenes) annotated to homologous proteins in the Protostome database (PANM-DB). The GO term and KEGG pathway analysis indicated genes involved in metabolism, phosphatidylinositol signalling system, aminobenzoate degradation, and T-cell receptor signalling pathway. Many genes associated with molluscan innate immunity were categorized under pathogen recognition receptor, TLR signalling pathway, MyD88 dependent pathway, endogenous ligands, immune effectors, antimicrobial peptides, apoptosis, and adaptation-related. The reproduction-associated unigenes showed homology to protein fem-1, spermatogenesis-associated protein, sperm associated antigen, and testis expressed sequences, among others. In addition, we identified key growth-related genes categorized under somatotrophic axis, muscle growth, chitinases and collagens. A total of 4822 Simple Sequence Repeats (SSRs) were also identified from the unigene sequences of I. fruhstorferi.

Conclusions

This is the first available genomic information for non-model land slug, I. fruhstorferi focusing on genes related to growth, immunity, and reproduction, with additional focus on microsatellites and repeating elements. The transcriptome provides access to greater number of traits of unknown relevance in the species that could be exploited for in-depth analyses of evolutionary plasticity and making informed choices during conservation planning. This would be appropriate for understanding the dynamics of the species on a priority basis considering the ecological, health, and social benefits.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5526-3) contains supplementary material, which is available to authorized users.

Transcriptome analysis of the threatened snail Ellobium chinense reveals candidate genes for adaptation and identifies SSRs for conservation genetics

Ellobium chinense (Pfeiffer, 1854) is a brackish pulmonate species that inhabits the bases of mangrove trees and is most commonly found in salt grass meadows. Threats to mangrove ecosystems due to habitat degradation and overexploitation have threatened the species with extinction. In South Korea, E. chinense has been assessed as vulnerable, but there are limited data on its population structure and distribution. The nucleotide and protein sequences for this species are not available in databases, which limits the understanding of adaptation-related traits. We sequenced an E. chinense cDNA library using the Illumina platform, and the subsequent bioinformatics analysis yielded 227,032 unigenes. Of these unigenes, 69,088 were annotated to matched protein and nucleotide sequences in databases, for an annotation rate of 30.42%. Among the predominant gene ontology terms, cellular and metabolic processes (under the biological process category), membrane and cell (under the cellular component category), and binding and catalytic activity (under the molecular function category) were noteworthy. In addition, 4850 unigenes were distributed to 15 Kyoto Encyclopaedia of Genes and Genomes based enrichment categories. Among the candidate genes related to adaptation, angiotensin I converting enzyme, adenylate cyclase activating polypeptide, and AMP-activated protein kinase were the most prominent. A total of 15,952 simple sequence repeats (SSRs) were identified in sequences of > 1 kb in length. The di- and trinucleotide repeat motifs were the most common. Among the repeat motif types, AG/CT, AC/GT, and AAC/GTT dominated. Our study provides the first comprehensive genomics dataset for E. chinense, which favors conservation programs for the restoration of the species and provides sufficient evidence for genetic variability among the wild populations.

Systems genetic and pharmacological analysis identifies candidate genes underlying mechanosensation in the von Frey test

Mechanical sensitivity is commonly affected in chronic pain and other neurological disorders. To discover mechanisms of individual differences in punctate mechanosensation, we performed quantitative trait locus (QTL) mapping of the response to von Frey monofilament stimulation in BXD recombinant inbred (BXD) mice. Significant loci were detected on mouse chromosome (Chr) 5 and 15, indicating the location of underlying polymorphisms that cause heritable variation in von Frey response. Convergent evidence from public gene expression data implicates candidate genes within the loci: von Frey thresholds were strongly correlated with baseline expression of Cacna2d1, Ift27 and Csnk1e in multiple brain regions of BXD strains. Systemic gabapentin and PF-670462, which target the protein products of Cacna2d1 and Csnk1e, respectively, significantly increased von Frey thresholds in a genotype-dependent manner in progenitors and BXD strains. Real-time polymerase chain reaction confirmed differential expression of Cacna2d1 and Csnk1e in multiple brain regions in progenitors and showed differential expression of Cacna2d1 and Csnk1e in the dorsal root ganglia of the progenitors and BXD strains grouped by QTL genotype. Thus, linkage mapping, transcript covariance and pharmacological testing suggest that genetic variation affecting Cacna2d1 and Csnk1e may contribute to individual differences in von Frey filament response. This study implicates Cacna2d1 and Ift27 in basal mechanosensation in line with their previously suspected role in mechanical hypersensitivity. Csnk1e is implicated for von Frey response for the first time. Further investigation is warranted to identify the specific polymorphisms involved and assess the relevance of these findings to clinical conditions of disturbed mechanosensation.

Successful intervention to mitigate an acetylcholinesterase inhibitor-induced rhinorrhea prescribing cascade: a case report

WHAT IS KNOWN AND OBJECTIVE

A prescribing cascade if often treated by discontinuing both medications. We describe an intervention to mitigate a prescribing cascade while continuing a clinically necessary medication without negatively impacting the patient.

CASE SUMMARY

A 77-year-old women experienced probable acetylcholinesterase inhibitor-induced rhinorrhea and subsequently self-medicated with diphenhydramine which lead to worsening cognitive function. We reduced the dose of the acetylcholinesterase inhibitor and discontinued the diphenhydramine. The symptoms of rhinorrhea were subsequently reduced without negatively impacting cognition.

WHAT IS NEW AND CONCLUSION

This was the first published prescribing cascade intervention that did not require discontinuation of both medications, which may be emulated in future prescribing cascade cases.

Sequencing and de novo assembly of visceral mass transcriptome of the critically endangered land snail Satsuma myomphala: Annotation and SSR discovery

Satsuma myomphala is critically endangered through loss of natural habitats, predation by natural enemies, and indiscriminate collection. It is a protected species in Korea but lacks genomic resources for an understanding of varied functional processes attributable to evolutionary success under natural habitats. For assessing the genetic information of S. myomphala, we performed for the first time, de novo transcriptome sequencing and functional annotation of expressed sequences using Illumina Next-Generation Sequencing (NGS) platform and bioinformatics analysis. We identified 103,774 unigenes of which 37,959, 12,890, and 17,699 were annotated in the PANM (Protostome DB), Unigene, and COG (Clusters of Orthologous Groups) databases, respectively. In addition, 14,451 unigenes were predicted under Gene Ontology functional categories, with 4581 assigned to a single category. Furthermore, 3369 sequences with 646 having Enzyme Commission (EC) numbers were mapped to 122 pathways in the Kyoto Encyclopedia of Genes and Genomes Pathway database. The prominent protein domains included the Zinc finger (C2H2-like), Reverse Transcriptase, Thioredoxin-like fold, and RNA recognition motif domain. Many unigenes with homology to immunity, defense, and reproduction-related genes were screened in the transcriptome. We also detected 3120 putative simple sequence repeats (SSRs) encompassing dinucleotide to hexanucleotide repeat motifs from >1kb unigene sequences. A list of PCR primers of SSR loci have been identified to study the genetic polymorphisms. The transcriptome data represents a valuable resource for further investigations on the species genome structure and biology. The unigenes information and microsatellites would provide an indispensable tool for conservation of the species in natural and adaptive environments.

Transcriptome sequencing and de novo characterization of Korean endemic land snail, Koreanohadra kurodana for functional transcripts and SSR markers

The Korean endemic land snail Koreanohadra kurodana (Gastropoda: Bradybaenidae) found in humid areas of broadleaf forests and shrubs have been considered vulnerable as the number of individuals are declining in recent years. The species is poorly characterized at the genomic level that limits the understanding of functions at the molecular and genetics level. In the present study, we performed de novo transcriptome sequencing to produce a comprehensive transcript dataset of visceral mass tissue of K. kurodana by the Illumina paired-end sequencing technology. Over 234 million quality reads were assembled to a total of 315,924 contigs and 191,071 unigenes, with an average and N50 length of 585.6 and 715 bp and 678 and 927 bp, respectively. Overall, 36.32 % of the unigenes found matches to known protein/nucleotide sequences in the public databases. The direction of the unigenes to functional categories was determined using COG, GO, KEGG, and InterProScan protein domain search. The GO analysis search resulted in 22,967 unigenes (12.02 %) being categorized into 40 functional groups. The KEGG annotation revealed that metabolism pathway genes were enriched. The most prominent protein motifs include the zinc finger, ribonuclease H, reverse transcriptase, and ankyrin repeat domains. The simple sequence repeats (SSRs) identified from >1 kb length of unigenes show a dominancy of dinucleotide repeat motifs followed with tri- and tetranucleotide motifs. A number of unigenes were putatively assessed to belong to adaptation and defense mechanisms including heat shock proteins 70, Toll-like receptor 4, AMP-activated protein kinase, aquaporin-2, etc. Our data provide a rich source for the identification and functional characterization of new genes and candidate polymorphic SSR markers in K. kurodana. The availability of transcriptome information ( http://bioinfo.sch.ac.kr/submission/ ) would promote the utilization of the resources for phylogenetics study and genetic diversity assessment.

De novo Transcriptome Generation and Annotation for Two Korean Endemic Land Snails, Aegista chejuensis and Aegista quelpartensis, Using Illumina Paired-End Sequencing Technology

Aegista chejuensis and Aegista quelpartensis (Family-Bradybaenidae) are endemic to Korea, and are considered vulnerable due to declines in their population. The limited genetic resources for these species restricts the ability to prioritize conservation efforts. We sequenced the transcriptomes of these species using Illumina paired-end technology. Approximately 257 and 240 million reads were obtained and assembled into 198,531 and 230,497 unigenes for A. chejuensis and A. quelpartensis, respectively. The average and N50 unigene lengths were 735.4 and 1073 bp, respectively, for A. chejuensis, and 705.6 and 1001 bp, respectively, for A. quelpartensis. In total, 68,484 (34.5%) and 77,745 (33.73%) unigenes for A. chejuensis and A. quelpartensis, respectively, were annotated to databases. Gene Ontology terms were assigned to 23,778 (11.98%) and 26,396 (11.45) unigenes, for A. chejuensis and A. quelpartensis, respectively, while 5050 and 5838 unigenes were mapped to 117 and 124 pathways in the Kyoto Encyclopedia of Genes and Genomes database. In addition, we identified and annotated 9542 and 10,395 putative simple sequence repeats (SSRs) in unigenes from A. chejuensis and A. quelpartensis, respectively. We designed a list of PCR primers flanking the putative SSR regions. These microsatellites may be utilized for future phylogenetics and conservation initiatives.

Sequencing, De Novo Assembly, and Annotation of the Transcriptome of the Endangered Freshwater Pearl Bivalve, Cristaria plicata, Provides Novel Insights into Functional Genes and Marker Discovery

BACKGROUND

The freshwater mussel Cristaria plicata (Bivalvia: Eulamellibranchia: Unionidae), is an economically important species in molluscan aquaculture due to its use in pearl farming. The species have been listed as endangered in South Korea due to the loss of natural habitats caused by anthropogenic activities. The decreasing population and a lack of genomic information on the species is concerning for environmentalists and conservationists. In this study, we conducted a de novo transcriptome sequencing and annotation analysis of C. plicata using Illumina HiSeq 2500 next-generation sequencing (NGS) technology, the Trinity assembler, and bioinformatics databases to prepare a sustainable resource for the identification of candidate genes involved in immunity, defense, and reproduction.

RESULTS

The C. plicata transcriptome analysis included a total of 286,152,584 raw reads and 281,322,837 clean reads. The de novo assembly identified a total of 453,931 contigs and 374,794 non-redundant unigenes with average lengths of 731.2 and 737.1 bp, respectively. Furthermore, 100% coverage of C. plicata mitochondrial genes within two unigenes supported the quality of the assembler. In total, 84,274 unigenes showed homology to entries in at least one database, and 23,246 unigenes were allocated to one or more Gene Ontology (GO) terms. The most prominent GO biological process, cellular component, and molecular function categories (level 2) were cellular process, membrane, and binding, respectively. A total of 4,776 unigenes were mapped to 123 biological pathways in the KEGG database. Based on the GO terms and KEGG annotation, the unigenes were suggested to be involved in immunity, stress responses, sex-determination, and reproduction. A total of 17,251 cDNA simple sequence repeats (cSSRs) were identified from 61,141 unigenes (size of >1 kb) with the most abundant being dinucleotide repeats.

CONCLUSIONS

This dataset represents the first transcriptome analysis of the endangered mollusc, C. plicata. The transcriptome provides a comprehensive sequence resource for the conservation of genetic information in this species and enrichment of the genetic database. The development of molecular markers will assist in the genetic improvement of C. plicata.

Transcriptome Characterization for Non-Model Endangered Lycaenids, Protantigius superans and Spindasis takanosis, Using Illumina HiSeq 2500 Sequencing

The Lycaenidae butterflies, Protantigius superans and Spindasis takanosis, are endangered insects in Korea known for their symbiotic association with ants. However, necessary genomic and transcriptomics data are lacking in these species, limiting conservation efforts. In this study, the P. superans and S. takanosis transcriptomes were deciphered using Illumina HiSeq 2500 sequencing. The P. superans and S. takanosis transcriptome data included a total of 254,340,693 and 245,110,582 clean reads assembled into 159,074 and 170,449 contigs and 107,950 and 121,140 unigenes, respectively. BLASTX hits (E-value of 1.0 × 10⁻⁵) against the known protein databases annotated a total of 46,754 and 51,908 transcripts for P. superans and S. takanosis. Approximately 41.25% and 38.68% of the unigenes for P. superans and S. takanosis found homologous sequences in Protostome DB (PANM-DB). BLAST2GO analysis confirmed 18,611 unigenes representing Gene Ontology (GO) terms and a total of 5259 unigenes assigned to 116 pathways for P. superans. For S. takanosis, a total of 6697 unigenes were assigned to 119 pathways using the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database. Additionally, 382,164 and 390,516 Simple Sequence Repeats (SSRs) were compiled from the unigenes of P. superans and S. takanosis, respectively. This is the first report to record new genes and their utilization for conservation of lycaenid species population and as a reference information for closely related species.

Intravenous Lacosamide in refractory nonconvulsive status epilepticus

BACKGROUND

Many patients present with refractory Status epilepticus (SE) despite multiple anti-epileptic drugs (AEDs). Lacosamide (LCM) was recently approved as an adjunct AED for partial-onset seizures. It has unique mechanism of modulating voltage-gated sodium channels by enhancing their slow inactivation. LCM has demonstrated efficacy in animal models of pharmacoresistant seizures. To date, there are isolated anecdotal reports of LCM use in SE.

OBJECTIVE

To report a single center experience with IV Lacosamide in patients with NCSE.

METHODS

Pharmacy records were reviewed to identify patients with SE who received IV LCM in our institution. Data on demographics, response to therapy and adverse effects/outcomes were analyzed. All patients had continuous EEG monitoring.

RESULTS

10 patients (4 men, 6 women), age 16-90 years with refractory SE were given LCM. Eight patients were in focal non-convulsive SE (NCSE), 2 were in generalized non-convulsive SE. The etiologies included anoxic brain injury, idiopathic, encephalitis, tumor, posterior reversible encephalopathy syndrome (PRES), stroke, and AVM. IV LCM was added after traditional AEDs, including drug-induced coma in some, failed to control the SE. NCSE resolved in 7/10 patients whereas 1/10 patient showed partial response with cessation of NCSE but still frequent electrographic seizures and 2/10 patients were resistant to therapy.

CONCLUSIONS

LCM is a useful adjunct in refractory NCSE. The IV formulation allows prompt administration in the intensive care unit setting. Response was seen especially in focal SE. Similar to other AEDs, response was poor in patients with postanoxic injury. Our data is limited by the small number of patients. Larger controlled studies are necessary to assess accurately the efficacy of IV LCM as an early treatment of SE.

Hyperglycaemia, hypercholesterolaemia and the risk for developing gastric dysplasia

BACKGROUND/GOALS

Gastric dysplasia is believed to be the penultimate stage of gastric carcinogenesis. Few studies have evaluated whether there is a relationship between such risk factors and gastric dysplasia. This case-control study was conducted to investigate the associations between obesity, serum glucose, lipids and gastric dysplasia.

STUDY

Endoscopic findings and pathology specimens were reviewed from 1 July 1997 to 31 December 2006 in the Health Promotion Center. One hundred thirty patients have the dysplasia in the stomach during screening endoscopy. The same number of controls was evaluated and matched to the gastric dysplasia group for age and gender.

RESULT

The univariate analysis showed that the dysplasia risk was slightly increased among persons with a higher low-density lipoprotein, lower high-density lipoprotein, impaired fasting glucose and higher total cholesterol. However, a higher body mass index and higher triglyceride level were not associated with the diagnosis of gastric dysplasia. In the multivariate-adjusted model, a higher low-density lipoprotein cholesterol and glucose were strongly associated with an increased risk of dysplasia compared to the controls. However, the body mass index, triglyceride and total cholesterol were not associated with the risk for dysplasia.

CONCLUSION

Hyperglycaemia and low-density lipoprotein cholesterol appear to be associated with the risk for gastric dysplasia. Further epidemiologic studies including a large cohort of patients with gastric dysplasia and adenocarcinoma are needed to clarify the association of low-density lipoprotein cholesterol, serum glucose and gastric carcinogenesis.

Mechanical and heat sensitization of cutaneous nociceptors in rats with experimental peripheral neuropathy

This study examined whether or not the properties of cutaneous nociceptive fibers are altered in the neuropathic state by comparing lumbars 5 and 6 spinal nerve ligation (SNL) rats with sham-operated controls. The rats with the unilateral SNL developed mechanical allodynia in the ipsilateral hind limb, whereas the sham group did not. Two to 5 weeks after the neuropathic or sham surgery, rats were subjected to single fiber-recording experiments to examine the properties of afferent fibers in the sural and plantar nerves. A total of 224 afferents in the C- and Adelta-ranges were characterized in the neuropathic and sham groups. Spontaneous activity was observed in 16 of 155 fibers in the neuropathic group and one of 69 fibers in the sham group. The response threshold of both the C- and Adelta-fibers to mechanical stimuli was lower in the neuropathic group than the sham group. The afferent fibers responsive to heat stimuli were all C-fibers, and none were Adelta-fibers. The response threshold of the C-fibers to the heat stimuli was lower in the neuropathic group than the sham group. The magnitude of the responses of both C- and Adelta-fibers to the suprathreshold intensity of the mechanical stimulus was greater in the neuropathic group than the sham group. However, the magnitude of the responses of C-fibers to the suprathreshold intensity of the heat stimulus in the neuropathic group was not different from that in the sham group. These results suggest that after a partial peripheral nerve injury, the nociceptors on the skin supplied by an uninjured nerve become sensitized to both mechanical and heat stimuli. This nociceptor sensitization can contribute to neuropathic pain.

Electro-acupuncture relieves chronic visceral hyperalgesia in rats

Acupuncture treatment is one of the most desirable choices for the management of pain including chronic visceral pain, but its scientific evidence and laws of action are not very clear at this point. In this study, we examined the immediate and cumulative effects of electro-acupuncture (EA) on chronic visceral pain induced by colorectal distention (CRD) stimuli in rats using an irritable bowel syndrome (IBS) model (a chronic visceral hypersensitivity model). The results demonstrated that EA could significantly depress both abnormally increased abdominal withdrawal reflex (AWR) scores and the magnitude of electromyograms (EMGs) recorded from the rectus abdominis in response to CRD stimulation at strengths of 20, 40, 60, and 80 mmHg. Repeated EA treatment for 14 days showed that the effects of EA on both abnormal AWRs and EMGs appeared 2-4 days after the start of the EA application session, gradually enhanced to its maximum within 8-12 days, and lasted 5 days after EA treatment stopped. These data provide evidence that visceral pain associated with the rat IBS model can be effectively treated by EA and opens up the possibility of clinical treatment of chronic visceral pain with acupuncture.

Oral testosterone undecanoate (Andriol) supplement therapy improves the quality of life for men with testosterone deficiency

In a single-blind, placebo-controlled study, the effects of a 3-month oral administration of 160 mg/day testosterone undecanoate (Andriol) on the quality of life of men with testosterone deficiency were evaluated. The subjects included ten men with primary hypogonadism and 29 with andropause with sexual dysfunction as the most common problem. The changes in subjective symptoms were evaluated by the PNUH QoL scoring system and the St. Louis University Questionnaire for androgen deficiency in aging males (ADAM). Digital rectal examination (DRE) was performed and serum testosterone, prostate-specific antigen (PSA) and liver profile were monitored. Testosterone undecanoate treatment (n = 33) significantly improved sexual dysfunction and symptom scores of metabolic, cardiopulmonary, musculoskeletal and gastrointestinal functions compared to baseline and to placebo (n = 6). ADAM score also significantly improved after 3 months of treatment. Serum testosterone was significantly increased compared to pretreatment levels only in the testosterone undecanoate group. In the placebo group, no significant changes compared to baseline were found for testosterone levels and QoL questionnaires. No abnormal findings were detected on DRE or laboratory findings in either group. Adverse events, such as gastrointestinal problems and fatigue, were mild and self-limiting. It is concluded that androgen supplement therapy with oral testosterone undecanoate (Andriol) restores the quality of life through improvement of general body functions in men with testosterone deficiency.

Efficacy of low-dose clarithromycin triple therapy and tinidazole-containing triple therapy for Helicobacter pylori eradication

BACKGROUND

Proton pump inhibitor-based triple therapies are recommended as the first-line treatment for Helicobacter pylori eradication.

AIM

To evaluate the efficacies of low-dose clarithromycin triple therapy and tinidazole-containing triple therapy in a metronidazole resistance prevalent area and to compare the efficacies with standard triple therapy.

METHODS

In a randomized, multicentre, prospective study, a total of 352 patients with duodenal ulcer or non-ulcer dyspepsia were randomly divided into three groups according to the administered regimen: OAC250 group (omeprazole, 20 mg, amoxicillin, 1000 mg, and clarithromycin, 250 mg), OAC500 group (omeprazole, 20 mg, amoxicillin, 1000 mg, and clarithromycin, 500 mg) and OTC group (omeprazole, 20 mg, tinidazole, 500 mg, and clarithromycin, 500 mg). The three groups received each regimen twice daily for 7 days. Upper gastrointestinal endoscopy was performed before and 4 weeks after treatment. H. pylori status was determined by rapid urease test and 13C urea breath test.

RESULTS

The eradication rates in the OAC250, OAC500 and OTC groups were 76.2%, 65.7% and 64.8% (95% confidence interval: 67.9-84.4%, 56.7-74.8% and 55.7-73.9%), respectively, by intention-to-treat analysis (P=0.149) and 92.8%, 87.2% and 84.1% (95% confidence interval: 84.4-97.3%, 77.9-93.8% and 73.9-91.2%), respectively, by per protocol analysis (P=0.088). All regimens were well tolerated and compliance was excellent.

CONCLUSIONS

Both low-dose clarithromycin triple therapy and tinidazole-containing triple therapy are effective and safe regimens for H. pylori eradication.

The changes in expression of three subtypes of TTX sensitive sodium channels in sensory neurons after spinal nerve ligation

Our previous studies showed that the ectopic discharges in injured sensory neurons and mechanical allodynia that developed after spinal nerve ligation were significantly reduced by application of a low concentration of tetrodotoxin (TTX) to the corresponding dorsal root ganglion (DRG) of the ligated spinal nerve. Based on these data, we hypothesized that expression of TTX-sensitive sodium channels is up-regulated in the injured sensory neurons and that such up-regulation plays an important role in the generation of ectopic discharges and thus pain behaviors in spinal nerve ligated neuropathic rats. To test this hypothesis, the present study examined the changes in three subtypes of TTX-sensitive sodium channels in the DRG after spinal nerve ligation. The changes in the total amount of mRNA for alpha-subunits of sodium channel brain type I (type I), brain type II (type II) and brain type III (type III) were determined by RNase protection assays (RPA). The population of DRG neurons expressing type III sodium channel protein was examined by an immunohistochemical method with antibodies to type III sodium channels. In the normal DRG, the level of mRNA for the type I sodium channel is high while that for type II and type III is very low. After spinal nerve ligation, the expression of type III mRNA was significantly increased at 16-h postoperatively (PO), doubled by 3 days PO and then was maintained at this high level until the end of the experiment (7 days PO). By contrast, the amount of mRNA for type I and type II sodium channels started to decrease at 1 day PO and were reduced to 25-50% of the normal control levels by 7 days after nerve ligation. Neurons showing positive immunostaining for type III sodium channels were rare ( approximately 3.2% of total population) in the normal DRG but increased after nerve ligation to 21% and 15% of the total neuronal population by 1 day and 7 days PO, respectively. Type III immunoreactivity was found preferentially in medium to large sized neurons. Thus the majority of neurons with cell bodies having diameters > or =40 microm became type III-positive after nerve ligation. The data indicate that the increased expression of type III sodium channels in axotomized sensory neurons may be the critical factor for the TTX sensitivity of ectopic discharges in injured sensory neurons and thus the generation of ectopic discharges and neuropathic pain behaviors in spinal nerve ligated rats.

Development of purinergic sensitivity in sensory neurons after peripheral nerve injury in the rat

Purinoceptors are present in the cell bodies as well as in both peripheral and central terminals of many sensory neurons, where they may play a role in sensory transmission, including pain. After peripheral nerve injury at the spinal nerve level, some axotomized afferent neurons develop ongoing discharges (ectopic discharges) that originate in the dorsal root ganglion (DRG). In the present study, we attempted to determine whether or not purinergic sensitivity develops in injured sensory neurons which display ectopic discharges, as well as in silent units. The L(4) and L(5) spinal nerves were ligated in Sprague-Dawley rats. Four to 21 days after the surgery, the DRGs with attached dorsal roots and spinal nerves were removed and ectopic discharges were recorded from teased dorsal root fascicles using an in vitro recording set-up. The results showed that 75.6 and 65.1% of the chronically axotomized DRG neurons displaying ectopic discharges enhanced their activity after application of adenosine 5'-triphosphate (ATP, 1 mM) or alpha,beta-methylene ATP (mATP, 100 microM), respectively. In addition, application of these purinoceptor agonists evoked activity in 7 of 28 axotomized DRG neurons, which did not show ongoing discharges. In contrast, only 1 of 34 DRG neurons acutely isolated from normal rats (no previous spinal nerve ligation) responded to either mATP or ATP. In most of the tested units, mATP-induced enhancement of ectopic discharges was blocked by non-specific P2X receptor antagonists, PPADS or suramin. The data from the present study suggest that purinergic sensitivity develops in DRG neurons after chronic axotomy and that this purinergic sensitivity is likely to be mediated by P2X purinoceptors. This acquired purinergic sensitivity may play an important functional role in the enhancement of ectopic discharges and exacerbation of pain upon sympathetic activation in the neuropathic pain state.

Complestatin is a noncompetitive peptide antagonist of N-methyl-D-aspartate and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/kainate receptors: secure blockade of ischemic neuronal death

Complestatin, a peptide derived from Streptomyces, was found to protect cultured cortical neurons from excitotoxicity induced by N-methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), or kainate. This neuroprotective behavior of complestatin was attributed to a blockade of Ca2+ ion entry and accumulation, after the activation of NMDA and AMPA/kainate receptors. Complestatin reversibly interfered with NMDA- and AMPA-mediated excitatory synaptic transmission. Complestatin also protected cortical neurons from prolonged deprivation of oxygen and glucose, more effectively than combined antagonists of NMDA and AMPA/kainate receptors. Neurotoxicity, evolving within 1 to 2 days after continuous exposure to combined NMDA and AMPA/kainate antagonists, was not observed in cortical cell cultures that were exposed to complestatin. Finally, complestatin dose dependently prevented neuronal death evolving within the inner nuclear and ganglion cell layers, after transient retinal ischemia. We conclude that complestatin possesses novel pharmacological properties that effectively prevent excitotoxicity under certain pathological conditions.

Attenuation of Zn2+ neurotoxicity by aspirin: role of N-type Ca2+ channel and the carboxyl acid group

Synaptically released Zn2+ ions enter into neurons primarily through voltage-gated Ca2+ channels (VGCC) or N-methyl-d-aspartate (NMDA) receptors, which can mediate pathological neuronal death. We studied the possibility (and underlying mechanisms) that aspirin, known to prevent NMDA neurotoxicity, would also attenuate Zn2+ neurotoxicity. Administration of 3 to 10 mM aspirin, in cortical cell cultures, attenuated the evolution of neuronal death following exposure to 300 microM Zn2+ for 30 min. This neuroprotective effect of aspirin was attributable to the prevention of Zn2+ ion entry. Aspirin interfered with inward currents and an increase in [Ca2+]i through VGCC and selective binding of omega-conotoxin, sensitive to N-type Ca2+ channel. The omega-conotoxins GVIA or MVIIC, the selective inhibitors of N-type Ca2+ channels, attenuated Zn2+ neurotoxicity. Aspirin derivatives lacking the carboxyl acid group did not reduce Zn2+ neurotoxicity. The present findings suggest that aspirin prevents Zn2+-mediated neuronal death by interfering with VGCC, and its action specifically requires the carboxyl acid group.

The effect of lumbar sympathectomy in the spinal nerve ligation model of neuropathic pain

To evaluate the sympathetic dependency of pain behaviors in an animal model of neuropathic pain, the effect of surgical sympathectomy on the mechanical sensitivity of the hindpaw was examined in rats with L5 spinal nerve ligation. Mechanical sensitivity was determined by measuring foot withdrawal thresholds to mechanical stimulation with von Frey filaments applied to the base of the third or fourth toe. Tight ligation of the segmental L5 spinal nerve led to the development of mechanical hypersensitivity in the hindpaw. The effects of 2 different procedures of surgical lumbar sympathectomy on mechanical hypersensitivity were compared, limited (resection of sympathetic chain/ganglia L2 to L4 segments) and extensive (resection of L2 to L6 segments) sympathectomies. Mechanical hypersensitivity produced by L5 spinal nerve ligation was partially but significantly reduced by both sympathectomy procedures. In a separate group of rats, the L5 spinal nerve was ligated while irritating the neighboring L4 spinal nerve. This procedure produced a lesser degree of mechanical hypersensitivity, and subsequent sympathectomy had no effect on these animals. These data suggest that sympathectomy is effective in this model only when the animals show severe mechanical hypersensitivity.

Ion channels associated with the ectopic discharges generated after segmental spinal nerve injury in the rat

In an attempt to identify important ion channels contributing to the generation of ectopic discharges, the present study examined the effects of ion channel blockers on ectopic discharges of injured sensory neurons after spinal nerve ligation. The main focus of the study was to examine the effect of the sodium channel blocker, tetrodotoxin (TTX), in order to identify important subtype(s) (i.e. TTX-sensitive and TTX-resistant) of sodium channels that are involved in ectopic discharge generation. In addition, the effects of potassium and calcium channel blockers were also tested for comparison with the results of previous studies. The dorsal root ganglion (DRG) of the injured segment was removed along with the dorsal root (DR) and the spinal nerve 7-14 days after spinal nerve ligation in the rat. The tissue was placed in an in-vitro recording chamber consisting of multiple compartments that were independently perfused with 35 degrees C artificial cerebrospinal fluid (ACSF). Single unit recordings were made from teased DR fibers. Once a spontaneously active unit was found and characterized, ACSF containing a channel blocker was perfused to the DRG, the site where almost all ectopic discharges originate after spinal nerve ligation. All the recorded spontaneously active units were found to be Abeta and Adelta fibers (no C fibers were detected). Perfusion of the DRG with a sodium channel blocker (lidocaine) at a dose much less than that required to block conduction of action potentials, significantly inhibited ectopic discharges in all recorded fibers. In addition, ectopic discharges were inhibited by TTX perfused to the DRG at a dose much lower (average of 22.1 nM) than that required to block TTX-resistant subtypes of sodium channels. The data suggest that TTX-sensitive sodium channels are likely to be involved in the generation of ectopic discharges. The present study also confirmed the results of previous studies on the additional potential roles of potassium and calcium channels, thus suggesting that multiple ion channels are likely to be involved in the generation of ectopic discharges.

Gastric lymphangioma

Gastric lymphangioma is a rare benign gastric tumor composed of unilocular or multilocular lymphatic spaces. On gastrofiberscopy a submucosal tumor covered with smooth transparent normal mucosa is revealed in the stomach with or without a stalk. Endoscopic ultrasonography has become an indispensable tool for differentiating these gastric tumors. Treatment of lymphangioma depends on its size, location, and presence of complications. Endoscopic resection is safe and easy and plays an important role in confirming the diagnosis and treatment of the tumors especially of small-sized ones. We report a case of gastric lymphangioma in a 68-yr-old woman who presented with nausea and vague epigastric discomfort for two months. She was diagnosed by gastrofiberscopy with endoscopic ultrasonography and treated successfully with endoscopic resection by strip biopsy method.

Sympathetic sprouting in the dorsal root ganglion after spinal nerve ligation: evidence of regenerative collateral sprouting

It is well documented that there is an increase in the number of sympathetic fibers within the dorsal root ganglion (DRG) after a peripheral nerve injury. The present study examined the numbers and distribution of sympathetic fibers in the DRG and their sprouting routes by utilizing various surgical manipulations and retrograde tracing and immunohistochemical staining methods in spinal nerve-ligated neuropathic rats. The appearance of many double immunostained fibers with antibodies to tyrosine hydroxylase (TH) and growth associated protein-43 (GAP-43) in the L5 DRG 1 week after L5 spinal nerve ligation, indicated sprouting of sympathetic fibers. The confined location of early sprouting sympathetic fibers in the distal half of the L5 DRG confirmed that sprouting fibers come primarily from the injured spinal nerve. A second cut proximal to the previously ligated L5 spinal nerve -- a process which would transect the regenerating sympathetic fibers extending from the injury site -- did not change the density of sympathetic fibers in the L5 DRG. When retrograde tracers (fast blue and diamidino yellow) were injected into the L5 spinal nerve and DRG, respectively, the number of double-labeled sympathetic postganglionic neurons was greatly increased after spinal nerve ligation, suggesting the increased number of sympathetic neurons projecting to both the spinal nerve and DRG. All these results indicate that many sympathetic fibers in the DRG are regenerating branches that are sprouting from the proximal part of the injured spinal nerve (regenerative collateral sprouting).

Facilitation of NMDA-induced currents and Ca2+ transients in the rat substantia gelatinosa neurons after ligation of L5-L6 spinal nerves

This study employing a rodent model of neuropathic pain investigated the influence of partial nerve injury on the ability of NMDA receptor activation to induce membrane currents and rises in cytosolic concentration of free calcium ([Ca2+]i) in the rat substantia gelatinosa (SG) neurons using simultaneous whole-cell patch-clamp recording and fura-2 calcium imaging in spinal slices. The novel findings are that: (I) L5-L6 spinal nerve ligation produces a sustained facilitation of NMDA-mediated membrane currents and [Ca2+]i rises both in the soma and dendrites of SG neurons on the injured side on post-operative days 4-13 after injury. (2) It appears that SG neurons in slices from injured rats recover from Ca2+ load less efficiently than neurons from naive rats. (3) The membrane depolarization-induced Ca2+ transients in SG neurons are not modified following spinal nerve ligation. The temporal profile of the changes in Ca2+ transients correlated well with the development of mechanical and thermal allodynia and hyperalgesia. These results suggest an important role of NMDA-mediated calcium signalling in the pathogenesis of neuropathic pain following spinal nerve injury.

Lack of pre-emptive analgesic effects of local anaesthetics on neuropathic pain

We investigated the significance of pre-emptive analgesia using a well-known model of neuropathic pain in rats. Lignocaine, bupivacaine or saline was applied locally to the left L5-L6 spinal nerve before or 4 days after nerve injury. Mechanical allodynia was then evaluated before and after injury. Pre- and post-injury treatment with local anaesthetics both resulted in a two- to threefold increase in the pain threshold, as manifested by a significant increase in von Frey measurements. However, this effect lasted only 24 h. Our study in rats questions the beneficial effect of a single dose of local anaesthetic as pre-emptive analgesia.

Potentiation of early necrotic death of glucose-starved pheochromocytoma 12 cells by nerve growth factor

Recently suggested is an arguable hypothesis that neurotrophins can induce necrosis but suppress apoptosis of target cells in some pathological conditions. We examined this hypothesis by tracing the type of NGF-promoted cell death occurring in a hypoglycemic condition at various angles, such as kinetic analyses, histological examinations of membrane alterations, morphological observations in ultra-structural changes, and determinations of DNA fragmentation. Glucose-starved cell death consisted of two kinetically different stages, suggesting that it be mixed with early and delayed death. Several lines of evidence revealed that NGF prominently enhanced the early death with necrotic characters. By contrast, apoptotic characters of glucose-starved delayed death were not much affected by NGF. Nifedipine, a voltage-gated calcium channel blocker, could completely compensate for the enhancement of the early glucose-starved death by NGF. Interestingly, the NGF-promoted cell death was also blocked by cycloheximide that did not keep PC12 cells alive from glucose starvation. Therefore, all the data in this study suggest that NGF accelerates the early necrosis of glucose-starved cell death probably through the alterations of intracellular calcium ions and protein syntheses.

Combined peripheral facial and abducens nerve palsy caused by caudal tegmental pontine infarction

Isolated peripheral facial and abducens nerve palsy could theoretically be caused by a caudal pontine infarction, but as far as we know, there has been no published case history which has demonstrated this point. We describe the cases of two hypertensive patients who showed combined peripheral facial and abducens nerve palsy without other neurologic symptoms or signs. Other than hypertension, there was no identifiable etiology. Magnetic resonance imaging demonstrated compatible isolated ipsilateral ischemic infarction of the caudal tegmental pons. The present cases indicate that a well-placed small pontine infarction can cause isolated peripheral facial and abducens nerve palsy.

Low dose of tetrodotoxin reduces neuropathic pain behaviors in an animal model

We hypothesize that the accumulation of tetrodotoxin (TTX) sensitive sodium channels in injured dorsal root ganglion (DRG) neurons plays a critically important role in the generation of ectopic discharges and mechanical allodynia after peripheral nerve injury. Using the segmental spinal nerve (L5) ligation model of neuropathic pain, this hypothesis was tested by examining the effect of TTX on the mechanical sensitivity of the affected hind paw. Various concentrations of TTX were applied topically to the L5 DRG by using chronically implanted polyethylene tubing. The data showed that application of TTX at low doses (12.5-50 nM), which are far less than those needed for blocking action potential conduction, produced a significant elevation of mechanical threshold in the paw for foot withdrawals, a sign of reduced allodynic behaviors. The data suggest that TTX-sensitive subtypes of sodium channels play an important role in maintaining allodynic behaviors in an animal model of neuropathic pain.

Spatial distribution of allozyme polymorphisms following clonal and sexual reproduction in populations of Rhus javanica (Anacardiaceae)

Rhus javanica L. (Anacardiaceae), a dioecious tree with both sexual reproduction and clonal growth, is widely distributed in warm temperate, subtropical, and tropical regions in east Asia. We used allozyme loci and spatial autocorrelation statistics to examine clonal structure and the spatial distribution of allozyme polymorphisms in two Korean populations. Populations of the species maintain moderate levels of allozyme variability (mean He=0.175, GST=0.060), and high levels of multilocus genotypic diversity (mean DG=0.971). Clone-pair distances ranged from 1.4 m to 57.4 m, and had high mean values of 24.0 m and 25.6 m in the two study populations. Approximate genetic patch widths were inferred to be 23-25 m. The results indicated that within populations there is moderate (one study population) or no (other study population) spatial genetic structure among sexually reproduced individuals, and vegetatively reproduced genotypes also are almost randomly distributed. The spatial genetic structure among sexually reproduced trees in the one case is probably caused by limited pollen dispersal in that population, and the lack of structure in the other probably results from the short time elapsed since founding. It appears that clonal reproduction also does not contribute substantially to genetic isolation by distance neither among the sexually reproduced individuals nor the total population. Ramets often establish long distances from their progenitors and thus do not substantially increase the degree of local consanguineous matings.

Characteristics of ectopic discharges in a rat neuropathic pain model

Injured afferent neurons produce spontaneous activity that is generated away from the normal impulse generation site. Since this activity, referred to as ectopic discharges, may play a significant role in neuropathic pain, it is important to systematically analyze the activity in various pain states. The present study used the segmental spinal nerve injury model of neuropathic pain to quantify the ectopic discharges from injured afferents in the neuropathic rat under various conditions. All aspects of measured ectopic discharges declined as postoperative time lengthened. Neuropathic pain behaviors declined in a similar fashion over the same time period. Surgical sympathectomy on neuropathic animals lowered the level of ectopic discharges along with neuropathic pain behaviors. The data indicate that the level of ectopic discharges is well correlated with that of pain behaviors in a rat neuropathic pain model, and this reinforces the supposition that ectopic discharges are important to the maintenance of neuropathic pain behaviors. The data suggest that there are two components of ectopic discharge generator mechanisms: sympathetically dependent and sympathetically independent components.

Ectopic discharges and adrenergic sensitivity of sensory neurons after spinal nerve injury

At various times after spinal nerve injury, dorsal root ganglia (DRGs) from injured segments were removed with attached dorsal roots and spinal nerves. In an in vitro recording chamber, spontaneously active units were recorded from teased dorsal root fascicles. Sustained spontaneous activity could first be recorded at 13 h after the ligation, but adrenergic sensitivity did not develop until 24 h after the injury. Almost all recorded activity originated from the DRG. Thus, the DRG is the most common site for ectopic discharge generation after spinal nerve injury and separate mechanisms seem to be involved in the development of ectopic discharges and adrenergic sensitivity.

Different strains and substrains of rats show different levels of neuropathic pain behaviors

This study compared and contrasted the manifestation of neuropathic pain behaviors in several strains of rats. These included ACI, Brown-Norway, Fischer 344, Lewis, Long-Evans, Sprague-Dawley, and Wistar-Furth, all obtained from Harlan Sprague-Dawley Inc. Comparison was also made between two substrains of Sprague-Dawley rats: one from Harlan and the other from Sasco. Neuropathic injury was produced by tightly ligating the left L5 and L6 spinal nerves with the animals under halothane anesthesia. Tests were conducted for 2 weeks to examine behavioral signs representing mechanical allodynia, cold allodynia, and spontaneous pain. There was no difference between strains in any of the tested behaviors before surgery. After neuropathic injury, rats in most groups developed high levels of behavioral signs of various components of neuropathic pain; however, some strains of rats showed weak behavioral signs of neuropathic pain. When a comparison was made between two substrains of Sprague-Dawley rats from two different sources, the ones from Sasco showed weaker behavioral signs than those from Harlan. When comparisons were made between different strains of rats from the same source (Harlan), Brown-Norway and Long-Evans rats showed the smallest magnitude of neuropathic pain behaviors. The data indicate that different strains and substrains of rats display different degrees of pain behaviors, suggesting that strains and substrains are important variables in the development of neuropathic pain after peripheral nerve injury.

Electrophysiological evidence for the role of substance P in retinohypothalamic transmission in the rat

The retinohypothalamic tract (RHT) is a neural pathway through which photic time cues are delivered directly to the mammalian circadian pacemaker in the suprachiasmatic nucleus (SCN). Although the excitatory amino acid glutamate is the primary neurotransmitter in the RHT, other substances such as substance P (SPq also have been suggested to play a role. The present study tested the hypothesis that SP participates in retinohypothalamic transmission and selectively modulates either N-methyl-D-aspartate (NMDA) or non-NMDA receptor-mediated neurotransmission. The SP antagonist L-703,606 depressed the excitatory postsynaptic current (EPSC) evoked by optic nerve stimulation in SCN neurons in rat hypothalamic slices. The SP antagonist also had a similar depressive effect on the NMDA and non-NMDA receptor-mediated components of the EPSC. These results suggest that SP is an excitatory neuromodulator contributing to the expression of both the NMDA and non-NMDA receptor-mediated components of retinohypothalamic transmission.

Changes in trkA expression in the dorsal root ganglion after peripheral nerve injury

Most of the biological effects of nerve growth factor (NGF) are mediated by TrkA, the high affinity receptor for NGF. Previous studies have shown that NGF levels in the dorsal root ganglia (DRG) fluctuate following a peripheral nerve injury. The present study examined changes of TrkA immunoreactivity and trkA mRNA expression in the DRG after segmental nerve ligation. In the normal L5 DRG of the rat, there were, on average, 4700 TrkA-immunoreactive (TrkA-IR) neurons, representing 42% of the total neuronal population. Following L5 spinal nerve ligation, the number of TrkA-IR neurons in the L5 DRG slowly declined, reducing by 25% at 1 week and 35% at 3 weeks postoperation (PO). In contrast, trkA mRNA in these ganglia showed a significant decrease from 3 days to 3 weeks PO and was followed by a full recovery at 2 months PO. The early decrease of trkA mRNA is likely due to deprivation of target-derived NGF, which is caused by nerve ligation, and the recovery might be because substitute sources of NGF become available. Despite the decline in trkA mRNA in the ganglion, 3000 injured DRG neurons sustain TrkA immunoreactivity, suggesting that exogenous NGF can still influence these TrkA expressing neurons, even though they are isolated from the periphery. Accordingly, the effects of endogenous NGF should be as well manifested by local administration of NGF to the ganglion as to the stump of the damaged nerve.

Preemptive intrathecal ketamine injection produces a long-lasting decrease in neuropathic pain behaviors in a rat model

BACKGROUND AND OBJECTIVES

Ketamine is an N-Methyl-D-Aspartate (NMDA) receptor antagonist, which has been found to effectively treat somatic and neuropathic pain. This study examines the effect (on neuropathic pain) of preemptive ketamine using different routes of administration (intrathecal versus intraperitoneal).

METHODS

The Institutional Animal Care and Use Committee approved the study. Thirty male Sprague-Dawley rats (250-275 g) were divided into three treatment groups [intrathecal saline/intraperitoneal saline or Control (CTL), intrathecal ketamine/intraperitoneal saline (ITK), and intrathecal saline/intraperitoneal ketamine (IPK)] prior to undergoing surgery to induce neuropathic pain by tight ligation of the left L5 and L6 spinal nerves. All drugs were given 15 minutes before nerve ligation. The ITK group received intrathecal ketamine (0.5% solution, 1 mg/kg), the IPK group received intraperitoneal ketamine (0.5% solution, 1 mg/kg), saline was given in equal volume (approximately 0.05 mL). Mechanical allodynia, cold allodynia, and ongoing pain behaviors indicative of neuropathic pain were assessed on postoperative days 1, 3, 7, and 14 using validated methods.

RESULTS

Compared with the CTL group, the ITK group showed a state of decreased mechanical allodynia, cold allodynia, and ongoing pain as revealed by the von Frey hair, acetone, and cold plate testing, respectively. Further, this decrease was sustained for at least 2 weeks. The IPK group showed intermediate results between the CTL and ITK.

CONCLUSIONS

Neuropathic pain behaviors were significantly reduced for at least 2 weeks after intrathecal ketamine was preemptively administered to animals undergoing surgery to induce neuropathic pain. The mechanism of action is thought to be prevention of spinal cord sensitization.

Receptor subtype mediating the adrenergic sensitivity of pain behavior and ectopic discharges in neuropathic Lewis rats

Receptor subtype mediating the adrenergic sensitivity of pain behavior and ectopic discharges in neuropathic Lewis rats. We attempted to identify the subtype of alpha-adrenergic receptor (alpha-AR) that is responsible for the sympathetic (adrenergic) dependency of neuropathic pain in the segmental spinal injury (SSI) model in the Lewis strain of rat. This model was chosen because our previous study showed that pain behaviors in this condition are particularly sensitive to systemic injection of phentolamine (PTL), a general alpha-AR blocker. We examined the effects of specific alpha1- and alpha2-AR blockers on 1) behavioral signs of mechanical allodynia, 2) ectopic discharges recorded in the in vivo condition, and 3) ectopic discharges recorded in an in vitro setup. One week after tight ligation of the L5 and L6 spinal nerves, mechanical thresholds of the paw for foot withdrawals were drastically lowered; we interpreted this change as a sign of mechanical allodynia. Signs of mechanical allodynia were significantly relieved by a systemic injection of PTL (a mixed alpha1- and alpha2-AR antagonist) or terazosin (TRZ, an alpha1-AR antagonist) but not by various alpha2-AR antagonists (idazoxan, rauwolscine, or yohimbine), suggesting that the alpha1-AR is in part the mediator of the signs of mechanical allodynia. Ongoing ectopic discharges were recorded from injured afferents in fascicles of the L5 dorsal root of the neuropathic rat with an in vivo recording setup. Ongoing discharge rate was significantly reduced after intraperitoneal injection of PTL or TRZ but not by idazoxan. In addition, by using an in vitro recording setup, spontaneous activity was recorded from teased dorsal root fibers in a segment in which the spinal nerve was previously ligated. Application of epinephrine to the perfusion bath enhanced ongoing discharges. This evoked activity was blocked by pretreatment with TRZ but not with idazoxan. This study demonstrated that both behavioral signs of mechanical allodynia and ectopic discharges of injured afferents in the Lewis neuropathic rat are in part mediated by mechanisms involving alpha1-ARs. These results suggest that the sympathetic dependency of neuropathic pain in the Lewis strain of the rat is mediated by the alpha1 subtype of AR.

Heritability of nociception II. 'Types' of nociception revealed by genetic correlation analysis

Clinical pain syndromes, and experimental assays of nociception, are differentially affected by manipulations such as drug administration and exposure to environmental stress. This suggests that there are different 'types' of pain. We exploited genetic differences among inbred strains of mice in an attempt to define these primary 'types'; that is, to identify the fundamental parameters of pain processing. Eleven randomly-chosen inbred mouse strains were tested for their basal sensitivity on 12 common measures of nociception. These measures provided for a range of different nociceptive dimensions including noxious stimulus modality, location, duration and etiology, among others. Since individual members of inbred strains are identical at all genetic loci, the observation of correlated strain means in any given pair of nociceptive assays is an index of genetic correlation between these assays, and hence an indication of common physiological mediation. Obtained correlation matrices were subjected to multivariate analyses to identify constellations of nociceptive assays with common genetic mediation. This analysis revealed three major clusters of nociception: (1) baseline thermal nociception, (2) spontaneously-emitted responses to chemical stimuli, and (3) baseline mechanical sensitivity and cutaneous hypersensitivity. Many other nociceptive parameters that might a priori have been considered closely related proved to be genetically divergent.

Heritability of nociception I: responses of 11 inbred mouse strains on 12 measures of nociception

It is generally acknowledged that humans display highly variable sensitivity to pain, including variable responses to identical injuries or pathologies. The possible contribution of genetic factors has, however, been largely overlooked. An emerging rodent literature documents the importance of genotype in mediating basal nociceptive sensitivity, in establishing a predisposition to neuropathic pain following neural injury, and in determining sensitivity to pharmacological agents and endogenous antinociception. One clear finding from these studies is that the effect of genotype is at least partially specific to the nociceptive assay being considered. In this report we begin to systematically describe and characterize genetic variability of nociception in a mammalian species, Mus musculus. We tested 11 readily-available inbred mouse strains (129/J, A/J, AKR/J, BALB/cJ, C3H/HeJ, C57BL/6J, C58/J, CBA/J, DBA/2J, RIIIS/J and SM/J) using 12 common measures of nociception. These included assays for thermal nociception (hot plate, Hargreaves' test, tail withdrawal), mechanical nociception (von Frey filaments), chemical nociception (abdominal constriction, carrageenan, formalin), and neuropathic pain (autotomy, Chung model peripheral nerve injury). We demonstrate the existence of clear strain differences in each assay, with 1.2 to 54-fold ranges of sensitivity. All nociceptive assays display moderate-to-high heritability (h2 = 0.30-0.76) and mediation by a limited number of apparent genetic loci. Data comparing inbred strains have considerable utility as a tool for understanding the genetics of nociception, and a particular relevance to transgenic studies.

Expression of neurotrophin mRNAs in the dorsal root ganglion after spinal nerve injury

Neurotrophins have specificity toward distinct subpopulations of dorsal root ganglion (DRG) neurons with different neurotrophin receptors. It has been suggested that neurotrophins also play important roles in mature DRG neurons after injury. In the present study, we examined the expression of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin 3 (NT-3) mRNAs in the DRG after a peripheral nerve injury. The data showed that following a spinal nerve ligation, the level of NGF mRNA increased 4 times over the normal level and was maintained at a high level for a period of 3 weeks. The induction of BDNF mRNA was brief (lasting less than 3 days) and lesser in quantity ( approximately 1. 7 times increase) compared to NGF expression. The expression of NT-3 mRNA was not detected either in normal or nerve injured rats. Results suggest that different neurotrophins play different functional roles in the DRG after spinal nerve injury.

The anti-allodynic effects of amitriptyline, gabapentin, and lidocaine in a rat model of neuropathic pain

The management of patients with neuropathic pain is challenging. There are only a few reports regarding the acute effects of the commonly used adjuvant drugs amitriptyline (AMI), gabapentin (GBP), and lidocaine (LDC) on neuropathic pain behaviors in animal models. Thus, the purpose of this study was to investigate the acute effects of AMI, GBP, and LDC on behavioral signs of mechanical allodynia and the site of action of these drugs using a rat model of neuropathic pain. Under general anesthesia with halothane, neuropathic injury was produced in rats by tightly ligating the left L5 and L6 spinal nerves. In Experiment 1, baseline mechanical allodynia data were recorded, and the animals were randomly divided into five groups: Group 1 received saline intraperitoneally (IP), Group 2 received AMI (1.5 mg/kg IP); Group 3 received GBP (50 mg/kg IP), Group 4 received an IV saline infusion for 10 min, and Group 5 received LDC (10-mg/kg IV infusion) for 10 min. Measurements of mechanical allodynia were repeated 0.5, 1, 2, and 4 h and 1, 3, and 7 days after treatment. In Experiment 2, rats were prepared similarly to the first experiment, and a single unit activity of continuous discharges of injured afferent fibers was recorded from the left L5 fascicles before and until 1 h after treatment. All animals developed neuropathic pain behavior within 7 days after surgery. All three tested drugs were effective in increasing the threshold for mechanical allodynia as early as 30 min after treatment, and the effect lasted for at least 1 h. Furthermore, AMI and LDC reduced the rate of continuing discharges of injured afferent fibers, whereas GBP did not influence these discharges. Our findings clearly demonstrate an attenuation of neuropathic pain behavior in rats treated with AMI, GBP, or LDC. Finally, the site of action of LDC seems to be primarily in the periphery, and that of GBP is exclusively central, whereas that of AMI seems to have both peripheral and central components.

IMPLICATIONS

In the present study, we examined the effectiveness of three drugs commonly used for the treatment of neuropathic pain. Systemic injections of amitriptyline, gabapentin, or lidocaine produced pain-relieving effects in this established model for neuropathic pain in rats, which supports their clinical use in managing patients with neuropathic pain syndromes.

The recent development of emergency medicine in South Korea

Emergency medicine has developed rapidly in South Korea in the past decade, giving Korea one of the most advanced systems of emergency medical care in Asia. This article reviews the overall health care system and medical climate in Korea, as well as the great progress made in establishing emergency medicine as a specialty. It also describes the many improvements implemented in academic emergency medicine, emergency patient care, and emergency medicine management systems. Although the current economic crisis offers new challenges, much optimism remains about the future of this new Korean specialty.

Anticholinesterase induces nicotinic receptor modulation

The effects of carbamate anticholinesterases, pyridostigmine and physostigmine, on the function of the nicotinic receptor (nAChR) in TE671 cells was studied, precluding their inhibition of acetylcholine hydrolysis by carbachol usage. In radioassay, the simultaneous application of carbachol and carbamates dose-dependently decreased carbachol-induced 22Na+ influx, compared with carbachol activation alone. Increasing cell preincubation in the presence of carbamates, however, potentiated influx at low concentrations in a time-dependent manner. This facilitating effect of carbamates, even at high concentrations, was significantly increased by washing out these drugs and was blocked by pretreatment with diisopropylfluorophosphate. Similar results were also obtained in whole-cell patch-clamp study. There were insignificant changes in desensitization properties during facilitation. It is thus supposed that facilitation cannot be explained by the inhibition of acetylcholine hydrolysis. These results support a previous hypothesis that acetylcholinesterase might modulate nAChR by an unknown mechanism. In addition, the clinical effects of carbamates may be partly attributed to this facilitation.

NGF-induced cytotoxicity in PC12 cells in a hypoglycemic environment

Surprisingly, we observed that nerve growth factor (NGF) potentiated death of PC12 cells induced by glucose withdrawal, although NGF is widely believed to exert its protective role against several types of cell death. Since either glucose withdrawal or NGF treatment increases intracellular calcium levels of target cells in many cases, we hypothesized that further increase of intracellular calcium by NGF may be a determinant factor in the NGF-mediated cell death. To test this hypothesis, we examined the effect of NGF on cell death pharmacologically by measuring cell viability and traced the changes of intracellular calcium in various conditions using a confocal laser microscope. NGF promoted cell death under a glucose-deprived condition in a manner dependent on extracellular calcium, and nifedipine, but not ryanodine, could partially block the cell death. NGF treatment augmented further intracellular calcium that had been elevated by glucose withdrawal, the event that nifedipine could block. In this study, therefore, we tentatively concluded that NGF potentiates cell death of starved PC12 cells by accelerating the initial increase of intracellular calcium through activation of a dihydropyridine-sensitive calcium channel.

Expression of nerve growth factor in the dorsal root ganglion after peripheral nerve injury

Nerve growth factor (NGF) is believed to play a critical role in altering the phenotypic and functional properties of dorsal root ganglion (DRG) cells after a pathological insult. The present study examined NGF protein levels and NGF immunoreactivity (NGF-IR) in the DRG at multiple time points following peripheral nerve injury. The NGF protein level in the ipsilateral DRG decreased dramatically at 6 h after the injury, but recovered to an almost normal level at 2 days. In accordance with the NGF level, the proportion of NGF-IR neurons also showed a significant decrease at 6 h after the injury, but recovered to the normal level at 3 days. In addition, NGF-IR can also be found in satellite cells at a time point of 3 days after the injury. These data suggest that there is an increase in synthesis of NGF within the DRG after peripheral nerve injury, which contributes to the recovery of NGF levels. The newly synthesized NGF may play important roles in the reactions of DRG neurons to peripheral nerve injury.

Comparison of sympathetic sprouting in sensory ganglia in three animal models of neuropathic pain

Sympathetic postganglionic fibers sprout in the dorsal root ganglion (DRG) after peripheral nerve injury. Therefore, one possible contributing factor of sympathetic dependency of neuropathic pain is the extent of sympathetic sprouting in the DRG after peripheral nerve injury. The present study compared the extent of sympathetic sprouting in the DRG as well as in the injured peripheral nerve in three rat neuropathic pain models: (1) the chronic constriction injury model (CCI); (2) the partial sciatic nerve ligation injury model (PSI); and (3) the segmental spinal nerve ligation injury model (SSI). All three methods of peripheral nerve injury produced behavioral signs of ongoing and evoked pain with some differences in the magnitude of each pain component. The density of sympathetic fibers in the DRG was significantly higher at all examined postoperative times than controls in the SSI model, while it was somewhat higher than controls only at the last examined postoperative time (20 weeks) in the CCI and PSI models. Therefore, data suggest that, although sympathetic changes in the DRG may contribute to neuropathic pain syndromes in the SSI model, other mechanisms seem to be more important in the CCI and PSI models at early times following peripheral nerve injury.

Nitric oxide mediates behavioral signs of neuropathic pain in an experimental rat model

This study was conducted to determine whether nitric oxide (NO) is involved in the maintenance of behavioral signs of neuropathic pain induced by tightly ligating the left L5 and L6 spinal nerves. Neuropathic rats showed behavioral signs representing mechanical allodynia, cold allodynia and cold-stress exacerbated ongoing pain. Mechanical allodynia was suppressed by Nomega-nitro-L-arginine methyl ester (L-NAME; 200, 100, 50, 10 microM/kg, i.p.), a nitric oxide synthase inhibitor, in a dose-dependent manner. Cold allodynia and cold-stress exacerbated ongoing pain was also attenuated by L-NAME. Neither Nomega-nitro-D-arginine methyl ester (D-NAME; 200 microM/kg) nor saline changed any of the neuropathic pain behaviors. These results suggested that NO plays an important role in the maintenance of the behavioral signs of neuropathic pain and is involved in common steps in the maintenance of the different modalities of pain such as mechanical allodynia and cold allodynia.

Strain differences in adrenergic sensitivity of neuropathic pain behaviors in an experimental rat model

The aim of this study was to examine and delineate the differences in adrenergic sensitivity of mechanical allodynic behavior among various strains of rats. Neuropathic injury was produced by tight ligation of the L5 and L6 spinal nerves in several strains of rats. The degree of mechanical allodynic behavior was estimated by measuring the mechanical threshold for paw flinching with von Frey filaments. Adrenergic sensitivity of the allodynic behavior was resolved by measuring changes of the mechanical threshold after intraperitoneal injection of phentolamine, an alpha-adrenergic receptor antagonist. Injection of phentolamine caused a significant but small increase in the thresholds for paw flinching in rats of most of the tested strains; however, in Lewis rats, the resulting threshold increase was extensive enough to eliminate allodynic behavior almost completely. It is concluded that there is a difference in adrenergic sensitivity to mechanical allodynic behavior among different strains of neuropathic rats. In particular, rats of the Lewis strain were extremely sensitive to systemic injection of an alpha-adrenergic receptor blocker.