[The diagnostic value of hydrogen sulfide breath test for small intestinal bacterial overgrowth].

Objective: To evaluate the diagnostic value of hydrogen sulfide breath test(SBT) for small intestinal bacterial overgrowth (SIBO). Methods: College students were enrolled to complete gastrointestinal symptom scale, food frequency questionnaire, lactulose hydrogen- methane breath test (LHMBT) and SBT. Based on the correlation between hydrogen sulfide(H2S) and hydrogen or methane gas,the receiver operating characteristic (ROC) curve of H2S was drawn and diagnostic criteria of SBT was defined. Results: A total of 300 subjects including 84 males and 216 females with age 17-32 (21.6±2.4) years were enrolled from April 2019 to December 2019 and divided into two groups.Two hundred and three patients reported SIBO discomforts with 99 (48.8%) LHMBT positive, while 38 (39.2%) were LHMBT positive in 97 health controls. Rise of H2S at 90 min was positively related with that of hydrogen (r=0.516, P<0.01), and H2S levels at 90 min were positively correlated with methane (r=0.632, P<0.01). A rise in H2S of ≥25.0 ppb or H2S levels ≥62.5 ppb at 90 min during lactulose breath test was considered positive for SIBO, that sensitivity, specificity and accuracy were 66.4%,79.1% and 73.3% respectively. H2S levels were significantly related to the amount of Vitamin B12 intake (P=0.011). H2S-positive subjects exhibited a constipation-predominant pattern. Conclusion: SBT is consistent with LHMBT, especially in constipation-predominant patients, which may provide a reference to the diagnosis of SIBO.

Oviposition Deterrents in Larval Frass of Potato Tuberworm Moth, Phthorimaea operculella (Lepidoptera: Gelechiidae).

The potato tuberworm moth (PTM) Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) is one of the most damaging pests of potato Solanum tuberosum L. in warm temperate and subtropical areas. Our previous experiment showed that extracts of larval frass of PTM deterred oviposition of conspecific females. In this study, we investigated the identification of chemicals in larval frass that were influencing the oviposition of PTM by behavioral bioassays and electroantennography analysis in the laboratory. Frass was collected from third and fourth instar larvae and combined analysis of gas chromatography coupled with electroantennography (GC-EAD) of dichloromethane extracts showed that eight compounds from larval frass extracts elicited repeatable antennal responses from mated females. Seven EAD-active compounds in frass volatile extract were identified by gas chromatography-mass spectrometry (GC-MS) as linoleic acid, octadecanoic acid, tricosane, pentacosane, heptacosane, nonacosane, and cholesterol. Oviposition bioassays indicated that frass extracts had a deterrent effect on egg laying, the deterrent activity increased with the concentration of frass extracts, and the threshold value for statistical significance in oviposition deterrence was in the range of 20-200 mg frass per cage. Linoleic acid, pentacosane, heptacosane, nonacosane, and cholesterol in larval frass volatiles were found to play a key role in repelling oviposition in a dose-dependent manner. We suggest that the bioactive compounds in larval frass are responsible for repelling oviposition of PTM, and n-alkanes, especially pentacosane, strongly deter oviposition and may be considered as a potential oviposition deterrent for potential applications.

[Biomechanical study of different kinds of internal fixation for the typeâ Hangman fracture, type â ¡ odontoid fracture and the C(2/3) disc injury: a finite-element analysis].

Objectives: To analyze the biomechanical stability of four kinds of internal fixation for the type Ⅰ Hangman fracture, type Ⅱ odontoid fracture and the C(2/3) disc injury by finite element (FE) analysis. Methods: Thin-section spiral computed tomography (0.5 mm) was performed on C(1) to C(3) region of cervical vertebra in healthy male volunteers.A three-dimensional hexahedral FE model of upper cervical spine was established by software (Mimics, GEOMAGICS, Pro/E and Ansys). Then the weakening of the strength of grid was performed to simulate the FE model of the type Ⅰ Hangman fracture, type Ⅱ odontoid fracture and the C(2/3) disc injury (FE/Fracture), the four internal fixation models: anterior cervical plate+ odontoid screw+ cage (FE/ACP+ OS+ cage), affixing rods from pedicle screws in C(2) to lateral mass screws in C(3)+ odontoid screw + cage (FE/C(2)PS+ C(3)LMS+ OS+ cage), affixing rods from pedicle screws in C(1) to pedicle screws in C(2) and lateral mass screws in C(3) (FE/C(1)PS+ C(2)PS+ C(3)LMS), anterior odontoid screw plate fixation system (FE/AOSP) were simulated on the FE/Fracture model.Flexion, extension, lateral bending and axial rotation were imposed on the FE/Intact, FE/Fracture and the four fixation models respectively. Results: The intact model of upper cervical spine (C(1)-C(3)) was established successfully, consisting of 259 641 nodes and 403 674 units.There was no significant difference among the FE/ACP+ OS+ cage, the FE/ C(2)PS+ C(3)LMS+ OS+ cage and the FE/AOSP of ROMC(1/2).During flexion, extension, left axial rotation and right axial rotation of ROMC(2)-C(3), the FE/AOSP decreased 70.7%, 74.4%, 38.9%, 41.1% respectively compared with the FE/C(1)PS+ C(2)PS+ C(3)LMS.The ROMC(2)-C(3) during flexion, extension, left lateral bending, right lateral bending, left axial rotation and right axial rotation in the FE/AOSP decreased for 82.2%, 82.8%, 73.2%, 64.8%, 72.2%, 81.5% respectively when compared with those in FE/ACP+ OS+ cage.The ROMC(2)-C(3) during flexion, extension, left lateral bending, right lateral bending, left axial rotation and right axial rotation in the FE/AOSP decreased 88.2%, 81.2%, 47.6%, 41.2%, 38.9%, 39.0% respectively when compared with those in FE/C(2)PS+ C(3)LMS+ OS+ cage.The stress concentrated on the connection between plate and screw in the FE/ACP+ OS+ cage, the FE/C(2)PS+ C(3)LMS+ OS+ cage and the FE/C(1)PS+ C(2)PS+ C(3)LMS, while it distributed evenly in the FE/AOSP. Conclusion: Anterior odontoid screw plate fixation system can be used to treat the type Ⅰ Hangman fracture, type Ⅱ odontoid fracture, and the C(2/3) disc injury and can reserve the function of atlanto-axial joint.

[A biomechanical evaluation of odontoid screw plate fixation system].

OBJECTIVE: To evaluate the biomechanical stability of anterior odontoid screw plate (AOSP). METHODS: Eight fresh-frozen cadaveric cervical spine specimens were subjected to stepwise destabilization of the C1-C3 complex, simulating a type Ⅰ Hangman fracture, type Ⅱ odontoid fracture, and the C2-3 disc injury. Intact specimens, fractured specimens, and fractured specimens with posterior, anterior fixation techniques were divided into six groups: control group (intact), injury group of type Ⅱ odontoid fracture and type Ⅰ Hangman fracture combined with C2-3 disk injury, after anterior cervical plate+ odontoid screw+ cage (ACP+ OS+ cage) group, after anterior odontoid screw plate (AOSP) fixation system group, after affixing rods from pedicle screws in C2 to lateral mass screws in C3+ odontoid screw (C2PS+ C3LMS+ OS) group, after affixing rods from pedicle screws in C1 to pedicle screws in C2 and lateral mass screws in C3 (C1PS+ C2PS+ C3LMS) group. The range of motion (ROM) and neutral zone of C1-C2 and C2-C3 segment was tested. RESULTS: There was statistically significant difference between the C1PS+ C2PS+ C3LMS fixation group and the AOSP fixation group of ROMC1-C2(P<0.05). During all loading modes, AOSP+ Bone graft fixation significantly outperformed the ACP+ OS+ cage fixation in limiting ROMC2-C3. During flexion and extension, AOSP fixation significantly outperformed the C1PS+ C2PS+ C3LMS fixation and C2PS+ C3LMS+ OS fixation in limiting ROMC2-C3. CONCLUSION: The AOSP fixation system has excellent biomechanical performance when dealing with type Ⅰ Hangman fracture, type Ⅱ odontoid fracture, and the C2-3 disc injury, and appear to be a safe and effective technique for dealing with the combined injury.

Genetic diversity analysis of fruit characteristics of hawthorn germplasm.

One hundred and six accessions of hawthorn intraspecific resources, from the National Germplasm Repository at Shenyang, were subjected to genetic diversity and principal component analysis based on evaluation data of 15 fruit traits. Results showed that the genetic diversity of hawthorn fruit traits varied. Among the 15 traits, the fruit shape variable coefficient had the most obvious evaluation, followed by fruit surface state, dot color, taste, weight of single fruit, sepal posture, peduncle form, and metula traits. These are the primary traits by which hawthorn could be classified in the future. The principal component demonstrated that these traits are the most influential factors of hawthorn fruit characteristics.

Cloning and characterization of the SERK1 gene in triploid Pingyi Tiancha [Malus hupehensis (Pamp.) Rehd. var. pingyiensis Jiang] and a tetraploid hybrid strain.

This study aims to explore the roles of somatic embryogenesis receptor-like kinase (SERK) in Malus hupehensis (Pingyi Tiancha). The full-length sequences of SERK1 in triploid Pingyi Tiancha (3n) and a tetraploid hybrid strain 33# (4n) were cloned, sequenced, and designated as MhSERK1 and MhdSERK1, respectively. Multiple alignments of amino acid sequences were conducted to identify similarity between MhSERK1 and MhdSERK1 and SERK sequences in other species, and a neighbor-joining phylogenetic tree was constructed to elucidate their phylogenetic relations. Expression levels of MhSERK1 and MhdSERK1 in different tissues and developmental stages were investigated using quantitative real-time PCR. The coding sequence lengths of MhSERK1 and MhdSERK1 were 1899 bp (encoding 632 amino acids) and 1881 bp (encoding 626 amino acids), respectively. Sequence analysis demonstrated that MhSERK1 and MhdSERK1 display high similarity to SERKs in other species, with a conserved intron/exon structure that is unique to members of the SERK family. Additionally, the phylogenetic tree showed that MhSERK1 and MhdSERK1 clustered with orange CitSERK (93%). Furthermore, MhSERK1 and MhdSERK1 were mainly expressed in the reproductive organs, in particular the ovary. Their expression levels were highest in young flowers and they differed among different tissues and organs. Our results suggest that MhSERK1 and MhdSERK1 are related to plant reproduction, and that MhSERK1 is related to apomixis in triploid Pingyi Tiancha.

Sympathetic activity in the rat: effects of anaesthesia on noradrenaline kinetics.

Noradrenaline (NA) kinetics represent an effective tool for evaluating the activity of the sympathetic system: thus plasma NA concentration, spillover rate (SOR) and metabolic clearance rate (MC) were measured in the rat. The dilution technique was adapted and validated: pithing that caused mechanical destruction of the spinal cord was shown to reduce drastically NA-SOR and plasma NA concentration with no effect on NA-MC. NA-SOR and plasma NA concentration were restored within their normal limits when 2.5 Hz electrical stimulation of the sympathetic roots was superimposed. Normal values of NA kinetics in non-anaesthetised normotensive 12-week-old rats are reported: NA-SOR=196.1+/-26.4 ng/kg/min, NA-MC=413.9+/-38.8 ml/kg/min and plasma NA=486+/-52 pg/ml. NA kinetic was investigated in response to anaesthesia, known to depress excitable tissues of the central nervous system and expected to depress the activity of the sympathetic system. When NA-SOR was significantly reduced during anaesthesia with either sodium pentobarbital or chloralose, plasma NA concentration was not changed because NA-MC was also reduced. Thus, plasma NA concentration can be a misleading marker of the sympathetic activity. The response of the sympathetic activity to four different anaesthetic agents is shown to be heterogeneous, ranging from inhibition to stimulation. Sodium pentobarbital anaesthesia was associated with a statistically significant reduction of both NA-SOR (105.6+/-14.1 ng/kg/min, P<0. 01) and NA-MC (239.3+/-18.7 ml/kg/min, P<0.001) while plasma NA was not changed (438+/-47 pg/ml). Chloralose reduced NA-SOR (101.6+/-20. 1 ng/kg/min, P<0.05) while ketamine did not (150.6+/-35.5 ng/kg/min, n.s.): both compounds reduced NA-MC (257.9+/-27.8 ml/kg/min, P<0.01 and 265.8+/-34.3 ml/kg/min, P<0.05, respectively). Diethyl ether was shown to increase both NA-SOR (472.2+/-111 ng/kg/min, P<0.05) and plasma NA concentration (1589+/-436 pg/ml, P<0.01), while NA-MC remained unchanged. Thus, any investigation of the activity of the sympathetic system in the anaesthetised rat has to take into account the specific effects related to the anaesthetic agent used.

Red blood cells participate in the metabolic clearance of catecholamines in the rat.

The aim of the present study was to investigate the possible role of erythrocytes in the metabolic clearance of catecholamines (CAs) in the rat. Intravenous infusion of exogenous CAs (dopamine -DA-, norepinephrine -NE-, or epinephrine -Epi-) was carried out at increasing doses to cover a range of plasma concentrations from the lower to the upper physiological and to pharmacological levels. Whatever the mechanism(s) underlying the CAs erythrocyte/plasma balance: 1. it seemed more efficient at lower concentrations of CAs; 2. it reached an apparent plateau where plasma and erythrocyte concentrations were not statistically different; 3. finally, saturation was suggested when further increase in plasma concentration was associated with a lower response in erythrocytes. This series of experiments confirms previous reported results with human erythrocytes and suggests that rat erythrocytes could transport CAs from their sites of release to their sites of elimination. In a second series of experiments, the intra-erythrocyte metabolism of CAs was investigated. DA was strikingly increased in plasma and in erythrocytes 2 hours after 1,2-dimethyl-3-hydroxy-4-pyridone (CP20), 100 mg/kg i.p., known to inhibit catechol-O-methyl transferase. Our data demonstrate an increase in glucuro-conjugated DA in vivo (24 hours after CP20 injection) as well as in vitro (3 hours incubation at 37 degrees C), suggesting activation of the glucuroconjugating pathway. Increased glucuroconjugated DA after in vitro incubation demonstrates intra-erythrocyte synthesis while increased concentration in Ringer-Hepes medium demonstrates an inside-out transport of glucuro-conjugate. These data are the first evidence in favour of an intra-erythrocyte glucuro-conjugation of CAs in the rat.

Neuronal metabolism of catecholamines in pithed and electrically stimulated rats.

The aim of the present study was to investigate a possible physiological equilibrium, assessed by statistically significant correlations, between pre-junctional mechanisms that regulate both release and reuptake of norepinephrine (NE) and post-junctional mechanisms that participate in the regulation of the smooth muscle cell and thus in the regulation of blood pressure. This study was carried out in pithed and electrically stimulated (2.5 Hz) rats to obtain an experimentally controlled release of NE. A radio-enzymatic assay was used to measure plasma concentrations of NE, index of NE release and levels of its deaminated metabolites 3,4-dihydroxyphenyl glycol (DHPG) and 3,4-dihydroxymandelic acid (DOMA). DHPG is known to be an index of NE reuptake and deamination while the physiological significance of DOMA remains unclear. Our results demonstrate a statistically significant correlation between plasma NE concentration and blood pressure on one hand, and between plasma NE and DHPG concentrations on the other. These correlations support our working hypothesis and suggest a physiological equilibrium between pre- and post-junctional phenomena in the control of blood pressure. During 2.5-Hz stimulation, plasma DHPG concentration was increased while plasma DOMA remained unchanged. This is consistent with activation of the reduction pathway and the consequent formation of DHPG by aldehyde reduction, while the oxidation pathway mediated by aldehyde dehydrogenase does not appear to play a major role in the presynaptic metabolism of reuptaken NE in the present experimental conditions. Further investigations are needed to investigate the apparent dissociation between the two enzymatic pathways involved in the second step of the deamination process.

Neuronal metabolism of catecholamines: plasma DHPG, DOMA and DOPAC.

Pre-synaptic endings of the sympathetic nervous fibers control the metabolism of catecholamines, particularly inactivating norepinephrine after its neuronal recapture. The present study was carried out to investigate this segment of the metabolism of catecholamines through measurements of DHPG, DOMA and DOPAC concentrations in plasma. A sensitive and specific radio-enzymatic assay was developed of which the major characteristic is to include the plasma sample in the incubation mixture without initial extraction of the deaminated metabolites. In the rat, there was a statistically significant correlation between norepinephrine and DHPG in both anesthetized and conscious conditions and after clonidine or guanethidine induced reduction of sympathetic activity; thus it can be suggested that plasma DHPG is a good index of neuronal metabolism of norepinephrine in this animal. In humans, our data indicate an interesting correlation between norepinephrine and DOMA concentrations in plasma in resting conditions and within three hours after clonidine. Further studies need to be carried out to establish whether DOMA is a better index of neuronal metabolism of norepinephrine than DHPG.