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1.
Sensors (Basel) ; 22(10)2022 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-35632253

RESUMO

Trochanteric fractures lead to severe functional deficits and gait disorders compared to femoral neck fractures. This study aims to investigate gait parameters related to gliding between tissues (gliding) after trochanteric fracture (TF) surgery. This study implemented a cross-sectional design and was conducted amongst patients who underwent TF surgery (n = 94) approximately three weeks post-trochanteric fracture surgery. The following parameters were evaluated: (1) gliding between tissues; (2) lateral femoral pain during loading; (3) maximum gait speed; (4) stride time variability and step time asymmetry as measures of gait cycle variability; (5) double stance ratio and single stance ratio for assessment of stance phase, (6) jerk; and (7) Locomotor rehabilitation index as a measure of force changes during gait. The gliding coefficient was significantly correlated with lateral femoral pain (r = 0.517), jerk root mean square (r = -0.433), and initial contact-loading response jerk (r = -0.459). The jerk of the force change value during gait was also effective in understanding the characteristics of the gait in the initial contact-loading response in patients with trochanteric fractures. Additionally, gliding is related not only to impairments such as pain but also to disabilities such as those affecting gait.


Assuntos
Fraturas do Quadril , Coxa da Perna , Estudos Transversais , Marcha/fisiologia , Fraturas do Quadril/cirurgia , Humanos , Dor
2.
J Clin Med ; 13(2)2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38276136

RESUMO

Cytotoxin-associated gene A (CagA) is an oncoprotein that H. pylori injects into the host's gastric epithelial cells and that induces proinflammatory cytokines, such as interleukin (IL)-18 and IL-1ß. As a result, it leads to atrophic gastritis (AG), a precancerous lesion of gastric cancer. On the other hand, host cells degrade CagA using autophagy systems. However, few studies exist about the single nucleotide polymorphisms (SNPs) in MAP1LC3A, MAP1LC3B, ATG4A, ATG4B, ATG4C, ATG7, and ATG13, which belong to the autophagy-related genes concerning AG. This study aimed to detect biomarkers associated with AG. Herein, H. pylori-positive subjects (n = 200) were divided into the AG (n = 94) and non-AG (n = 106) groups. Thirty tag SNPs were selected from the above seven candidate genes. The SNP frequency between the two groups was analyzed. The frequency of the C/T or T/T genotype at rs4683787 of ATG7 was significantly lower in the AG group than in the non-AG group (p = 0.034, odds ratio = 0.535). Based on multivariate analysis, the C/C genotype of rs4684787 and age were independently associated with gastric mucosal atrophy. This finding helps stratify the patients needing timely endoscopic screening or early eradication of H. pylori.

3.
Hepatogastroenterology ; 60(125): 1217-21, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23803385

RESUMO

BACKGROUND/AIMS: Despite recent advances in surgical techniques, blood loss is an important factor associated with postoperative outcomes in pancreatectomy. It is useful to identify risk factors of increased blood loss. METHODOLOGY: The clinical records of 161 patients who underwent an elective pancreatectomy for peripancreatic diseases between 1994 and March 2011 were retrospectively examined. Univariate and multivariate analysis of clinicopathological and surgical parameters influencing intraoperative blood loss were performed. We determined the cut-off value of the amount of blood loss based on the analyzed results. RESULTS: The mean and median blood loss was 1346±901 and 1070 mL, respectively. Red cell blood transfusion was performed in 72 patients (45%). Based on ROC analysis, the predictive value of blood loss in patients who received red cell blood transfusion was 880 mL (p <0.001); however, blood loss was not significantly associated with postoperative complications (p = 0.40). The cut-off level of estimated amount of blood loss in the present study was set at 880 mL. Male patients, fatty pancreas, higher serum alkaline phosphatase level, longer operating time, performance of pancreaticoduodenectomy (PD) and combined resections of adjacent major vessels were associated with significantly more increased blood loss (p <0.05). Based on multivariate analysis, longer operation time over 480 minutes and performance of PD were significantly associated with increased blood loss (p <0.05). CONCLUSIONS: Attempting to reduce operating time in cases of PD is necessary to reduce intraoperative blood loss.


Assuntos
Perda Sanguínea Cirúrgica , Pancreatectomia/efeitos adversos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Transfusão de Eritrócitos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pancreaticoduodenectomia/efeitos adversos , Estudos Retrospectivos
4.
J Biosci Bioeng ; 136(1): 20-27, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37221113

RESUMO

Enterococcus faecalis strain DB-5 is a lactic acid bacterium newly isolated from the Japanese mandarin orange (mikan). The DB-5 strain produces organic acid from various carbohydrate sources including glycerol and starch. To gain deeper insights into its potential application in lactic acid fermentation (LAF), the genome and fermentation analyses of E. faecalis DB-5 were performed. Whole genome sequencing was carried out using the DNBSEQ platform. After trimming and assembly, the total size of the assembled genome was revealed to be 3,048,630 bp, distributed into 63 contigs with an N50 value of 203,673. The genome has 37.2% GC content, 2928 coding DNA sequences, and 54 putative RNA genes. The DB-5 strain harbored two l-lactate dehydrogenases (L-LDHs), both of which conserved the catalytic domain sequences. The optical purity measurement showed that strain DB-5 is homofermentative and produced only l-lactic acid (LA), which correlated with genome-based pathway analysis. To confirm its LA productivity at high temperatures, open repeated batch fermentation was performed at 45 °C using sucrose as a carbon source. The volumetric LA productivity of DB-5 was averaged at 3.66 g L-1 h-1 for 24 h during the 3rd to 11th fermentation cycles. E. faecalis DB-5 could efficiently convert around 94% of sucrose to LA throughout the fermentation cycles at 45 °C. These genomic characteristics and fermentation properties of E. faecalis DB-5 provide beneficial information for a deeper understanding of the functional properties of future high-temperature LAFs from biomass resources.


Assuntos
Citrus , Enterococcus faecalis , Ácido Láctico , Enterococcus faecalis/genética , Enterococcus faecalis/metabolismo , Fermentação , L-Lactato Desidrogenase/metabolismo , Ácido Láctico/metabolismo , Citrus/microbiologia
5.
AIDS Patient Care STDS ; 37(5): 253-267, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37083443

RESUMO

We conducted a web-based survey targeting physicians in specialties of treating sexually transmitted infection (STI) and/or human immunodeficiency virus (HIV) patients to understand the current STI/HIV care practices and their acceptability of and barriers to the prescription of pre-exposure prophylaxis (PrEP) in Japan. A descriptive analysis was used to summarize survey responses. Univariate and multivariable logistic regression were performed to identify factors associated with willingness to prescribe PrEP. Of 316 survey respondents, 57 were specialized in HIV, 90 STI/Urology/Proctology, 55 Obstetrics/Gynecology, and 114 General Practice/Internal Medicine/Dermatology. Proportion of HIV-specialized physicians who interview the patients about risk behaviors tended to be higher than other physician groups (84.2% vs. 54.8%, 47.3%, and 50.9%, respectively), and 53 - 75% of non-HIV-specialized physicians reported that they were incapable of making decisions on HIV medications. Higher PrEP knowledge enhanced the willingness to recommend and prescribe PrEP drugs (odds ratio: 2.31, 95% confidence interval: 1.30-4.10, p = 0.0044), and 45.4% physicians with no PrEP knowledge raised the concern of incapability to respond and manage when an individual is infected with HIV. Educational opportunities on management and prevention measures for both STI and HIV may encourage non-HIV-specialized physicians to be involved in HIV care and to enhance initiation of HIV tests and adoption of PrEP.


Assuntos
Fármacos Anti-HIV , Infecções por HIV , Profilaxia Pré-Exposição , Infecções Sexualmente Transmissíveis , Humanos , Masculino , Infecções por HIV/tratamento farmacológico , Infecções por HIV/prevenção & controle , HIV , Estudos Transversais , População do Leste Asiático , Fármacos Anti-HIV/uso terapêutico , Conhecimentos, Atitudes e Prática em Saúde , Padrões de Prática Médica , Infecções Sexualmente Transmissíveis/prevenção & controle , Pessoal de Saúde , Homossexualidade Masculina
6.
Genes Environ ; 45(1): 18, 2023 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-37198664

RESUMO

BACKGROUND: Helicobacter pylori secretes cytotoxin-associated gene A (CagA) into the gastric epithelium, causing gastric mucosal atrophy (GMA) and gastric cancer. In contrast, host cells degrade CagA via autophagy. However, the association between polymorphisms in autophagy-related genes and GMA must be fully elucidated. RESULTS: We evaluated the association between single nucleotide polymorphisms (SNPs) in autophagy-related genes (low-density lipoprotein receptor-related protein 1, LRP1; capping actin protein of muscle Z-line alpha subunit 1, CAPAZ1; and lysosomal-associated membrane protein 1, LAMP1) and GMA in 200 H. pylori-positive individuals. The frequency of the T/T genotype at rs1800137 in LRP1 was significantly lower in the GMA group than in the non-GMA group (p = 0.018, odds ratio [OR] = 0.188). The frequencies of the G/A or A/A genotype at rs4423118 and T/A or A/A genotype at rs58618380 of CAPAZ1 in the GMA group were significantly higher than those in the non-GMA group (p = 0.029 and p = 0.027, respectively). Multivariate analysis revealed that C/C or C/T genotype at rs1800137, T/A or A/A genotype at rs58618380, and age were independent risk factors for GMA (p = 0.038, p = 0.023, and p = 0.006, respectively). Furthermore, individuals with the rs1800137 C/C or C/T genotype of LRP1 had a 5.3-fold higher susceptibility to GMA. These genetic tests may provide future directions for precision medicine for individuals more likely to develop GMA. CONCLUSION: LRP1 and CAPZA1 polymorphisms may be associated with the development of GMA.

7.
Gerontol Geriatr Med ; 9: 23337214231214405, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38035263

RESUMO

A trochanteric fracture is one type of hip fracture. Management of postoperative pain after trochanteric fracture that is caused by decreased gliding between tissues in the lateral thigh is not established. The aim of this study was to examine the effect of compression of the thigh using an elastic bandage on trochanteric fracture after surgery. Multicenter randomized controlled trial was conducted in collaboration with the Comprehensive Rehabilitation Unit (sub-acute rehabilitation Unit) in two hospitals. Eligible volunteers (n = 34) with trochanteric fractures after surgery were randomly assigned to two groups. In the treatment group, participants practiced standing and walking under compression of the thigh with an elastic bandage. The control group was blinded to the intervention and practiced standing and walking under non-compression of the thigh with an elastic bandage. Both groups underwent a standard physical therapy program 2 times a day, daily. Two-way repeated measures of ANOVA showed significant main effect between the groups for gliding between tissue (p < .001), lateral femoral pain (p < .001), subcutaneous tissue thickness (p = .044). Compression of the thigh with an elastic bandage significantly improved subcutaneous tissue thickness, gliding between tissues, lateral thigh pain. Gait velocity improved with these functional improvements.

8.
J Clin Med ; 12(16)2023 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-37629426

RESUMO

Helicobacter pylori (H. pylori) infection causes a progression to atrophic gastritis and results in gastric cancer. Cytotoxin-associated gene A (CagA), a major virulence factor of H. pylori, is injected into gastric epithelial cells using the type IV secretion system. On the other hand, gastric epithelial cells degrade CagA using an autophagy system, which is strictly regulated by the autophagy-related (ATG) genes. This study aimed to identify SNPs in ATG5, ATG10, ATG12, and ATG16L1 associated with gastric mucosal atrophy (GMA). Here, two-hundred H. pylori-positive participants without gastric cancer were included. The degree of GMA was evaluated via the pepsinogen method. Twenty-five SNPs located in the four candidate genes were selected as tag SNPs. The frequency of each SNP between the GMA and the non-GMA group was evaluated. The rs6431655, rs6431659, and rs4663136 in ATG16L1 and rs26537 in ATG12 were independently associated with GMA. Of these four SNPs, the G/G genotype of rs6431659 in ATG16L1 has the highest odd ratio (Odds ratio = 3.835, 95% confidence intervals = 1.337-1.005, p = 0.008). Further functional analyses and prospective analyses with a larger sample size are required.

9.
Hepatogastroenterology ; 59(118): 1964-9, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22819916

RESUMO

BACKGROUND/AIMS: The present study aimed to elucidate the relationship between microvessel count (MVC) according to CD34 expression and clinicopathological characteristics or prognosis in pancreatic carcinoma (PC) patients who underwent hepatectomy. METHODOLOGY: CD34 expression was analyzed using immunohistochemical methods. Mean MVC in 5 areas per specimen and clinicopathological factors were consecutively examined in 42 PC patients. RESULTS: Median MVC for PC patients was 123/mm2, which was applied as a cut-off value. Higher MVC was significantly associated with the advanced Japanese tumor-node-metastasis stage IVa and IVb (p=0.034). Univariate survival analysis identified higher carcinoembryonic antigen (CEA) and CA19-9 level, infiltrative type on macroscopic examination, invasive ductal carcinoma, node metastasis and higher tumor-node-metastasis classification were significantly associated with poor survival. The 5-year overall survival rate in the higher MVC group tended to be lower than that in the higher MVC group (37 vs. 55%), but not statistically significant (p=0.15). CONCLUSIONS: Tumor MVC might be a candidate prognostic marker of PC patient survival after pancreatectomy and further investigation in a larger series is warranted to clarify the significance of this marker.


Assuntos
Microvasos/patologia , Pancreatectomia , Neoplasias Pancreáticas/irrigação sanguínea , Neoplasias Pancreáticas/cirurgia , Antígenos CD34/análise , Intervalo Livre de Doença , Feminino , Gastrostomia , Humanos , Imuno-Histoquímica , Japão , Estimativa de Kaplan-Meier , Masculino , Microvasos/imunologia , Pessoa de Meia-Idade , Análise Multivariada , Pancreatectomia/efeitos adversos , Pancreatectomia/métodos , Pancreatectomia/mortalidade , Neoplasias Pancreáticas/mortalidade , Neoplasias Pancreáticas/patologia , Pancreaticoduodenectomia , Pancreaticojejunostomia , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Neoplasias Pancreáticas
10.
Microbiol Resour Announc ; 11(2): e0116021, 2022 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-35084226

RESUMO

Weissella soli strain DB-2 is a lactic acid bacterium that was isolated from nukadoko in Japan. We report the draft genome sequence of Weissella soli strain DB-2 to determine the presence of the genes responsible for exopolysaccharide biosynthesis, with the aim of further probiotic evaluation.

11.
Materials (Basel) ; 15(8)2022 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-35454420

RESUMO

Superabsorbent polymers (SAPs) are used as internal curing agents in cementitious materials, which reduce autogenous shrinkage in concrete as they have a low water-to-cement ratios and improve the freeze-thaw resistance. However, the compressive strength of concrete may also be reduced due to additional voids in the hydrated cement matrix. In this study, we fabricated a delayed absorption type of SAP (I-SAP) composed of cross-linked modified acrylate and studied its absorption characteristics and effect on compressive strength after 28 days. Furthermore, the effect of curing conditions on the strength of concrete and hydrated cement paste with SAP were investigated. The absorption capacity of I-SAP in the synthetic pore solution and deionised water was examined and compared with that of a conventional SAP, and the former was absorbed more by I-SAP. The results revealed that the compressive strength of concrete increased with the addition of I-SAP, particularly with the curing condition of 60% RH. Although the compressive strength of hydrated cement paste with I-SAP reduced in water or sealed curing conditions, no loss of strength in the paste cured at 60% RH was seen. The cement matrix densification due to hydration of belite around the SAP surface is the main mechanism for strength development in concrete cured at sealed and 60% RH. However, the voids formed by SAP control the compressive strength of hydrated paste.

12.
Microbiol Resour Announc ; 11(2): e0111421, 2022 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-35112903

RESUMO

We analyzed the bacterial diversity of root nodule and rhizosphere soil samples of edamame collected in Ebina, Japan. The major population identified from the nodules belonged to the genus Bradyrhizobium, and the rhizosphere soil in the open field has a higher abundance of the Rhizobiales order bacteria than that in the greenhouse.

13.
Diagnostics (Basel) ; 12(3)2022 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-35328125

RESUMO

Duodenogastric reflux (DGR) causes bile reflux gastritis (BRG) and may develop into gastric cancer. DGR is classified as primary in non-operated stomachs or secondary to surgical intervention. Primary DGR and Helicobacter pylori (H. pylori) infection are reportedly related. However, the mechanism is not fully understood. This study aimed to elucidate the relationship between H. pylori infection and pyloric incompetence in a non-operated stomach. A total of 502 non-operated participants who underwent an upper intestinal endoscopy were prospectively enrolled. Endoscopic findings (EAC, endoscopic atrophy classification; nodular gastritis; xanthoma; fundic gland polyp; and incompetence of pylorus), sex, age, gastrin, pepsinogen (PG) I and PG II levels were evaluated. PG I/PG II ratio, anti-H. pylori-Ab positivity, and atrophic gastritis status were significantly different between the normal and incompetent pylori (p = 0.043, <0.001, and 0.001, respectively). Open-type atrophic gastritis was significantly higher in the incompetent pylori. Incompetence of the pylorus and EAC were moderately correlated (Cramer's V = 0.25). Multivariate analysis revealed that the presence of anti-H. pylori-Ab was the only independent factor associated with the incompetence of the pylorus, with an adjusted odds ratio of 2.70 (95% CI: 1.47−4.94, p = 0.001). In conclusion, pyloric incompetence was associated with H. pylori infection and moderately correlated to the severity of atrophic gastritis in non-operated stomachs.

14.
Diagnostics (Basel) ; 12(8)2022 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-36010338

RESUMO

Helicobacter pylori infection results in gastric cancer (GC) with gastric mucosal atrophy (GMA). Some single-nucleotide polymorphisms (SNPs) in the prostate stem cell antigen gene (PSCA) are associated with GC and duodenal ulcers. However, the relationship of other identified SNPs in PSCA with these diseases remains unclear. Herein, the association between PSCA SNPs and GMA among 195 Japanese individuals with H. pylori infection was evaluated. The definition of GMA or non-GMA was based on serum pepsinogen levels or endoscopic findings. Five tag PSCA SNPs were analyzed using PCR high-resolution melting curve analysis with nonlabelled probes. The frequencies of alleles and the genotypes of each tag SNP were compared between the GMA and non-GMA groups. Subsequently, a genetic test was performed using associated SNPs as biomarkers to detect patients developing GMA. Two tag PSCA SNPs (rs2920280 and rs2294008) were related to GMA susceptibility. Individuals with the rs2920280 G/G genotype or the rs2294008 T/T genotype in PSCA had 3.5- and 2.1-fold susceptibility to GMA, respectively. In conclusion, SNP rs2920280 is a possible biomarker for detecting individuals developing GMA. PSCA polymorphisms may be useful biomarkers for predicting GMA linked to GC risk and a screening endoscopy strategy to detect GC related to early stage H. pylori associated GMA.

15.
Microbiol Resour Announc ; 10(40): e0070521, 2021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34617781

RESUMO

Bacillus paranthracis strain DB-4 was isolated from nukadoko in Japan. We report the draft genome sequence of this strain to provide insights into the survival mechanisms of lactic acid bacteria in fermented rice bran.

16.
Mol Inform ; 39(1-2): e1800155, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31589809

RESUMO

Classification of the biological activities of chemical substances is important for developing new medicines efficiently. Various machine learning methods are often employed to screen large libraries of compounds and predict the activities of new substances by training the molecular structure-activity relationships. One such method is graph classification, in which a molecular structure can be represented in terms of a labeled graph with nodes that correspond to atoms and edges that correspond to the bonds between these atoms. In a conventional graph definition, atomic symbols and bond orders are employed as node and edge labels, respectively. In this study, we developed new graph definitions using the assignment of atom and bond types in the force fields of molecular dynamics methods as node and edge labels, respectively. We found that these graph definitions improved the accuracies of activity classifications for chemical substances using graph kernels with support vector machines and deep neural networks. The higher accuracies obtained using our proposed definitions can enhance the development of the materials informatics using graph-based machine learning methods.


Assuntos
Azepinas/química , Benzenossulfonatos/química , Aprendizado de Máquina , Simulação de Dinâmica Molecular , Estrutura Molecular , Relação Quantitativa Estrutura-Atividade
17.
Sci Rep ; 8(1): 16472, 2018 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-30405204

RESUMO

The amount of water drainage from Kushiro Coal Mine in Hokkaido, Japan decreased on the day of all M ≥ 7.5 earthquakes with epicenters within 300 km of the mine during the monitoring period and increased after these earthquakes. This is a valuable finding which would give us a clue to understand pre- and post-seismic rockmass behaviors and contribute for progress in earthquake prediction in future.

18.
J Antibiot (Tokyo) ; 70(1): 84-89, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27328866

RESUMO

In the course of our screening program for inhibitors of lipopolysaccharide binding to cellular receptor CD14, a potent inhibitory activity was detected in the cultured broth of Pseudoalteromonas sp. SANK 71903. Four active compounds, ogipeptins A, B, C and D, were isolated from the cultured broth. The structures of these compounds were elucidated by physicochemical data and spectral analyses, and they were determined to be new cyclic lipopeptides.


Assuntos
Antibacterianos/isolamento & purificação , Lipopeptídeos/isolamento & purificação , Lipopolissacarídeos/antagonistas & inibidores , Peptídeos Cíclicos/isolamento & purificação , Antibacterianos/química , Antibacterianos/farmacologia , Lipopeptídeos/química , Lipopeptídeos/farmacologia , Receptores de Lipopolissacarídeos/metabolismo , Lipopolissacarídeos/metabolismo , Peptídeos Cíclicos/química , Peptídeos Cíclicos/farmacologia , Análise Espectral
19.
J Antibiot (Tokyo) ; 70(1): 79-83, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27381520

RESUMO

A library of secondary metabolites from microorganisms was screened to identify novel inhibitors against lipopolysaccharide (LPS), a strong stimulant of innate immunity. Novel cyclic peptides, ogipeptin A, B, C and D, were identified in the culture broth of the marine bacterium Pseudoalteromonas sp. SANK 71903. These compounds blocked LPS binding to the cluster of differentiation 14 (CD14) in vitro with IC50 values of 4.8, 6.0, 4.1 and 5.6 nm, respectively, and attenuated tumor necrosis factor-α secretion from LPS-stimulated macrophage-like cells. These compounds also displayed antimicrobial activity against Escherichia coli with minimum inhibitory concentrations ranging from 0.25 µg ml-1 to 1 µg ml-1. Thus, novel antibiotics that inhibited LPS-induced innate immune reactions were identified in this study.


Assuntos
Antibacterianos/farmacologia , Lipopolissacarídeos/antagonistas & inibidores , Peptídeos Cíclicos/farmacologia , Pseudoalteromonas/metabolismo , Antibacterianos/isolamento & purificação , Escherichia coli/efeitos dos fármacos , Imunidade Inata/efeitos dos fármacos , Concentração Inibidora 50 , Lipopolissacarídeos/imunologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Testes de Sensibilidade Microbiana , Peptídeos Cíclicos/isolamento & purificação , Metabolismo Secundário , Fator de Necrose Tumoral alfa/metabolismo
20.
Arch Oral Biol ; 51(10): 930-9, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16774733

RESUMO

Internal capsule (IC) stimulation has been used clinically to alleviate central pain. However, the neuronal mechanisms underlying pain relief by IC stimulation are poorly understood. In order to elucidate the analgesic mechanism, the effect of IC conditioning stimulation on nociceptive neurons in the rat medullary dorsal horn was investigated in the present study. Rats were anaesthetized with N(2)O-O(2) (2:1) and 0.5% halothane and were immobilized with pancuronium bromide. Two kinds of nociceptive neurons, wide dynamic range (WDR) and nociceptive specific (NS) neurons, responding to noxious stimulations of the face and oral structures were recorded in the trigeminal caudal nucleus and the medial reticular subnuclei. A test stimulus with a single rectangular pulse (2ms in duration, 5-70V) was applied to the centre of the receptive field. Responses in 55.9% of the WDR neurons and in 60% of the NS neurons were inhibited by conditioning stimuli to the ipsilateral IC with trains of 33 pulses (100-300microA) at 330Hz. The percents of peak inhibitory effects on WDR neurons and NS neurons were 78.1+/-25.0% (n=19) and 89.0+/-13.6% (n=3), respectively. The inhibitory effect continued for conditioning-test intervals of up to 500ms. Effective sites for conditioning stimulation were concentrated in the lateral side of the IC. These findings suggest that modulation of nociceptive transmission by IC stimulation occurs at second-order neurons via a presynaptic phenomenon by corticofugal fibers in the IC.


Assuntos
Cápsula Interna/fisiologia , Bulbo/fisiologia , Nociceptores/fisiologia , Células do Corno Posterior/fisiologia , Animais , Condicionamento Psicológico , Estimulação Elétrica/métodos , Face/inervação , Masculino , Boca/inervação , Inibição Neural/fisiologia , Neurônios Aferentes/fisiologia , Ratos , Ratos Sprague-Dawley , Núcleo Inferior Caudal do Nervo Trigêmeo/fisiologia
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