Dual effect of temperature on the human epithelial Na+ channel

The amiloride-sensitive epithelial sodium channel (ENaC) is the rate-limiting step for sodium reabsorption in the distal segments of the nephron, in the colon and in the airways. Its activity is regulated by intracellular and extracellular factors but the mechanisms of this regulation are not yet completely understood. Recently, we have shown that the fast regulation of ENaC by the extracellular [Na⁺], a phenomenon termed self-inhibition, is temperature dependent. In the present study we examined the effects of temperature on the single-channel properties of ENaC. Single-channel recordings from excised patches showed that the channel open probability (P _o, estimated from the number of open channels N·P _o, where N is the total number of channels) increased on average two- to threefold while the single-channel conductance decreased by about half when the temperature of the perfusion solution was lowered from ~30 to ~15 °C. The effects of temperature on the single-channel conductance and P _o explain the changes of the macroscopic current that can be observed upon temperature changes and, in particular, the paradoxical effect of temperature on the current carried by ENaC.     

Physiological and behavioral effects of prior aversive stimulation (preshock) in the rat

Physiological and behavioral measures were assessed in rats that had been previously exposed to unsignaled inescapable intense shock (preshock). Animals subjected to such prior aversive stimulation exhibited greater adrenocortical steroid response compared to nonpreshocked controls when subsequently tested in the open field. An increment in defecation was also observed, with ambulation and rearing behavior being markedly inhibited in the preshocked rat during these sessions.     

Neglected medial swivel dislocation of talonavicular joint with calcaneus,cuboid and 5th metatarsal fractures – A case report

Talonavicular dislocation is a rare injury. Isolated medial or lateral talonavicular dislocations without disruption of subtalar joint are known as medial or lateral swivel dislocations respectively, both being extremely rare. We describe a rare case of neglected medial swivel dislocation with concomitant calcaneus, cuboid and 5th metatarsal fracture, which was managed with open reduction and fixation of talonavicular joint with k-wires and an external distractor. At 1 year follow up the patient was mobilizing full weight bearing without any pain or deformity, the radiographs showing well located talonavicular joint and healed calcaneus, cuboid and 5th metatarsal fractures. This is the first reported case of medial swivel talonavicular dislocation with associated calcaneum, cuboid and 5th metatarsal fracture to the best of our knowledge. This case report highlights the importance of maintaining high level of suspicion for diagnosing midfoot injuries in a polytraumatized patient as well as need of accurate and timely reduction of dislocation for good functional outcome.Level of clinical evidenceLevel 4.     

Is male gender a risk factor for conversion of laparoscopic into open cholecystectomy?

Background: Based on a clinical observation that the conversion rate of laparoscopic cholecystectomy (LC) to open cholecystectomy (OC) is higher in males, we decided to review our records and to verify whether a significant difference in conversion rates exists between sexes. Methods: A retrospective study on conversion rates of elective laparoscopic cholecystectomy (LC) into open cholecystectomy (LC) in relation to gender was carried out in 329 patients: 267 females and 62 males. Results: Our data revealed that the probability of conversion is fivefold greater in males than females, 21% vs 4.5%, respectively (p=0.0001). We attribute this striking difference to significantly more adhesions (p=0.0002) and anatomical difficulties (p=0.003) in males during LC, leading to conversion. Conclusions: We conclude that conversion of LC to OC is more prevalent among males and is probably attributable to a greater incidence of anatomical difficulties.     

Different behavioural patterns induced by apomorphine: evidence that the method of administration determines the behavioural response to the drug

The behavioural effects of s.c. injected apomorphine was studied on habituated rats in a test-box designed to measure 8 different components of behaviour. Apomorphine, 1 mg/kg, induced two different behaviours: The "G-type" of behaviour characterized by compulsive gnawing and the "LS-type" of behaviour characterized by increased locomotion, sniffing and repetitive head and limb movements. G-type behaviour was induced when apomorphine, dissolved by heating, was injected s.c. into the flank of the animal. LS-type behaviour was induced both when apomorphine, dissolved by heating, was injected s.c. into the neck and when it was dissolved by heating together with a high concentration of ascorbic acid (1 mg/ml) and injected s.c. into the flank. G-type behaviour could not be elicited by changing the dose which induced LS-type behaviour or vice versa. We therefore conclude that these different behavioural effects of apomorphine were not dose--response effects but were elicited by at least two different synaptic mechanisms in the brain. Experimentally induced changes from one of these apomorphine-induced behaviours to another can therefore not merely be interpreted as a change in the intensity of the behavioural response as is done in e.g. commonly used stereotypy rating scales.     

Epidemiologic Correlation and Drug Resistance Analysis of Pathogenic Bacteria in Different Open Limb Injury External Conditions

ObjectiveTo study the epidemiological correlation and drug resistance of external factors of infection caused by open injury of limbs to pathogens.MethodsThis experiment is a retrospective study. We took the geographical location and climate of Nanchang, Jiangxi Province, China as the background, analyzed 2017 strains of pathogens from 1589 patients with limb trauma infection in a University Affiliated Hospital from 2012 to 2017. Patients were divided into three groups according to the type of incision: I, In‐hospital infection of clean limb incision, II, In‐hospital infection with open injury, III, Community infection with open injury of the limb. Groups II and Groups III were divided into six subgroups according to the causes of trauma, including: accidents from non‐motor vehicles, machinery, cutting/piercing, pedestrian injuries, struck by/against, pedal cycles, and other injuries. We found eight common pathogens of orthopedic infection, which were mainly divided into Gram‐positive bacteria (G+, mainly including Staphylococcus) and Gram‐negative bacteria (G‐, mainly Enterobacteriaceae). The relationship between main pathogens and damage mechanism, apparent temperature and relative humidity was discussed in this study. SPSS v22.0 was used for statistical analysis of the data. Friedman''s two‐way ANOVA was used to analyze the difference between the injury mechanism and incidence of pathogenic bacteria. Linear regression was used to determine the trend between the incidence of major pathogens and seasonal temperature and humidity. The level of significance was set as P < 0.05.ResultsThere was no significant difference in the distribution of pathogens between Groups II and Groups III (P>0.05). The drug resistance of Groups III was significantly higher than that of Groups II and Groups I. G+ bacteria were resistant to cephalosporin, ceftriaxone and other cephalosporins and erythromycin and other macrolides. They were sensitive to vancomycin and linezolid. G‐ were resistant to the first‐ and the second‐generation cephalosporins, including cefotetan and cefazolin, and ampicillin and other penicillins, while they were sensitive to third‐generation cephalosporins, such as ceftazidime, as well as to levofloxacin and other quinolones, meropenem, and other beta‐lactamases. The correlation between the injury mechanism and infection of pathogenic bacteria was not significant. The monthly average apparent temperature and relative humidity were correlated with the infection rate of pathogenic bacteria.ConclusionIn open injury of extremities, apparent temperature and relative humidity is an important risk factor for infection by pathogenic bacteria and the drug resistance of pathogenic bacteria in out‐of‐hospital infection was lower than that of hospital infection.     

基于影像学特征对骨质疏松性椎体压缩骨折病人经皮椎体成形术后同椎体再发骨折的预测研究

目的 探讨基于影像学特征对骨质疏松性椎体压缩骨折（OVCF）病人经皮椎体成形术（PVP）后的列线图模型预测术椎椎体再发骨折的价值。方法 回顾性纳入急性OVCF并行PVP后的病人93例。所有病人均行X线及MRI检查,根据椎体再发骨折诊断标准将病人分为再发骨折组（48例）和无再发骨折组（45例）。采用t检验和卡方检验比较2组间临床资料及影像特征的差异,对差异有统计学意义的指标进行多因素Logistic回归分析,获取再发骨折的独立危险因素,采用R软件建立列线图模型并绘制其校准曲线。采用受试者操作特征（ROC）曲线评估模型的预测效能,计算ROC曲线下面积（AUC）。应用校准曲线对列线图模型进行验证。结果 再发骨折组的椎体高度恢复率、延伸至终板的骨折线、椎体内裂隙（IVC）、骨水泥周围积液及骨水泥-终板未接触（NPEC）与无再发骨折组的差异均有统计学意义（均P<0.05）;多因素Logistic回归分析显示延伸至终板的骨折线[优势比（OR）=3.232]、存在IVC(OR=27.117)和NPEC(OR=1.993)及较高的椎体高度恢复率（OR=2.943）为同椎体再发骨折的独立危险因素（...     

Fate and distribution of brevetoxin (PbTx) following lysis of Karenia brevis by algicidal bacteria, including analysis of open A-ring derivatives

Flavobacteriaceae (strain S03) and Cytophaga sp. (strain 41-DBG2) are algicidal bacteria active against the brevetoxin (PbTx)-producing, red tide dinoflagellate, Karenia brevis. Little is known about the fate of PbTx associated with K. brevis cells following attack by such bacteria. The fate and distribution of PbTx in K. brevis cultures exposed to these algicidal strains were thus examined by receptor binding assay and liquid chromatography/mass spectrometry (LC/MS) in three size fractions (>5, 0.22–5, <0.22 μm) over a 2-week time course. In control cultures, brevetoxin concentrations in the >5 μm particulate size fraction correlated with changes in cell density, whereas significant increases in dissolved (i.e., <0.22 μm) toxin were observed in the later stages of culture growth. Exposure of K. brevis to either of the two algicidal bacteria tested caused cell lysis, coinciding with a rapid decline in the >5 μm PbTX size fraction and a simultaneous release of dissolved toxin into the growth medium. Upon cell lysis, dissolved brevetoxin accounted for ca. 60% of total toxin and consisted of 51–82% open A-ring derivatives. Open A-ring PbTx-2 and PbTx-3 derivatives bound with lower affinity (approximately 22- and 57-fold, respectively) to voltage-gated sodium channels and were considerably less cytotoxic (86- and 142-fold, respectively) to N2A cells than their individual parent toxins (i.e., PbTx-2 and PbTx-3). These novel findings of changes in PbTx size-fractioned distribution and overall reduction in K. brevis toxicity following attack by algicidal bacteria improve our understanding of potential trophic transfer routes and the fate of PbTx during red tide events. Moreover, this information will be important to consider when evaluating the potential role of algicidal bacteria in harmful algal bloom (HAB) management strategies involving control of bloom populations.     

小型猪急性心肌梗死后心力衰竭模型的构建

目的研究开放拉长塑料细管法（OPS）对HBV转基因小鼠（P21^HBxPHBx）和白内障小鼠（cataract mice,cM）胚胎冷冻效果。方法采用乙二醇作为冷冻保护剂,以昆明小鼠为对照,用OPS法对CM及P21^HBxPHBx两种小鼠3．5d的胚胎进行玻璃化冷冻,并比较KM、CM及P21^HBxPHBx获得胚胎数,解冻后胚胎的复苏率及发育率。结果KM、CM及P21^HBxPHBx小鼠平均获得胚胎数分别为31．12、19．32、9．14枚;解冻后的复苏率分别为95．6％、79-3％、80．3％;发育率分别为94．7％、73．8％、56．6％。表明HBV转基因小鼠的获得胚胎数明显低于昆明小鼠,解冻后三种小鼠的胚胎复苏率之间无显著差别,而解冻后发育率,P21^HBxPHBx小鼠要明显低于KM小鼠。结论转基因小鼠超排数及解冻后发育率低于昆明小鼠,而白内障模型小鼠和昆明小鼠比较不显著。     

Dental arch changes after anterior open bite treatment in the mixed dentition produced by miniscrew-supported palatal crib vs conventional fixed palatal crib:: A randomized clinical trial

ObjectivesTo evaluate the dental arch changes produced by the miniscrew-supported palatal crib (MSPC) and the conventional fixed palatal crib (CFPC) after the treatment of patients with anterior open bite (AOB) attributed to the tongue-thrusting habit in the mixed dentition stage.Materials and MethodsA total of 26 children aged 8 to 11 years with an AOB were randomly distributed into two equal groups; the MSPC group was treated using a palatal crib supported by two miniscrews inserted paramedially, whereas the CFPC group was treated using a conventional fixed palatal crib soldered to bands. Digital models were obtained pretreatment and after a follow-up duration of 9 months.ResultsThe MSPC group included 12 participants (9 girls and 3 boys; mean age, 9.4 ± 0.75 years), and the CFPC group included 12 participants (10 girls and 2 boys; mean age, 9.0 ± 0.73 years). The amount of AOB closure was similar in both groups: 3.97 ± 1.44 mm in the MSPC group and 3.97 ± 0.89 mm in the CFPC group. There was significant mesial movement of the maxillary first molar in the CFPC (−1.42 ± 0.99 mm) compared with the MSPC group (−0.53 ± 0.32 mm).ConclusionsBoth appliances resulted in similar improvement in the amount of AOB closure. There was significantly more mesial movement of the maxillary first molars in the CFPC group compared with the MSPC group.