Subthreshold Oscillations Induced By Spinal Nerve Injury In Dissociated Muscle And Cutaneous Afferents Of Mouse DRG

Whole cell patch-clamp recordings were obtained from dissociated mouse lumbar dorsal root ganglion (DRG) neurons. Recordings were made from control neurons and neurons axotomized by transection of the corresponding spinal nerve 1-2 days prior to dissociation. Medium to large muscle and cutaneous afferent neurons were identified by retrograde transport of True Blue or Fluoro-Gold injected into the corresponding peripheral tissue. Action potentials were classified as non-inflected spikes (A(0)) and inflected spikes (A(inf)). High-frequency, low-amplitude subthreshold membrane potential oscillations were observed in 8% of control A(0) neurons, but their incidence increased to 31% in the nerve injury group. Fifty percent of axotomized muscle afferent A(0) cells displayed oscillations, while 26% of axotomized cutaneous afferents exhibited oscillations. Lower-frequency oscillations were also observed in a small fraction (4%) of A(inf) neurons on strong depolarization. Their numbers were increased after the nerve injury, but the difference was not statistically significant. The oscillations often triggered burst firing in distinct patterns of action potential activity. These results indicate that injury-induced membrane oscillations of DRG neurons, previously observed in whole DRG of rats, are present in dissociated DRG neurons of the adult mouse. Moreover, these observations indicate that both muscle and cutaneous afferents in the A(beta) size range give rise to injury-induced membrane oscillations, with muscle afferents being more prone to develop oscillations.     

Antibody to Hepatitis B Surface Antigen in Vaccinated Health Care Workers

Background

Health care workers (HCWs) in Armed Forces are immunised against Hepatitis B virus (HBV), however they are not subjected to anti-HBs (antibody to Hepatitis B surface antigen) assessment after primary vaccination. The present study was undertaken to determine the protection offered by HBV vaccine in HCW.

Methods

Cross-sectional study was carried out at tertiary care hospital. A total 146 HBV vaccine compliant HCW were evaluated for quantitative anti-HBs by enzyme immune assay.

Result

129 (88.4%) subjects had protective levels of anti-HBs. Higher age at vaccination was an important risk factor in low vaccine response. Decline in anti-HBs with time was evident. Anti-HBs levels were more than 10mIU/ml in subjects even after 11 years of primary vaccination. There was no difference in protection in booster and non booster groups.

Conclusion

Age is the most important factor in HBV vaccine response. Booster dose of HBV vaccine is not necessary in healthy HCW for atleast ten years after primary vaccination. The study recommends early primary vaccination of HCW and ‘initial’ anti-HBs assay for confirmation of vaccine response.Key Words: Anti-Hepatitis B surface antigen, Health care workers, Hepatitis B virus vaccine     

急性缺血再灌注肾损伤过程中Mg2+及K+协同胰岛素的对抗效应

目的:在肾移植术后可能发生急性缺血再灌注性肾损伤.作者前期实验表明在肾缺血再灌注期间注射胰岛素可减轻缺血再灌注肾损伤,在此基础上,在胰岛素溶液中加入天冬氨酸钾镁,观察Mg2 ,K 协同胰岛素对家兔急性肾缺血再灌注损伤的影响,并分析其可能机制.方法:实验于2002-02/04在泸州医学院生理实验室完成,动物实验方法符合动物伦理学要求.①实验材料及方法:选用健康成年日本大耳白兔27只,按随机数字表法分为3组(n=9),即缺血再灌注组、缺血再灌注胰岛素处理组及对照组,前两组采用钳夹肾动脉法建立急性肾缺血再灌注肾损伤模型,缺血再灌注胰岛素处理组再灌注的同时给予胰岛素溶液,含胰岛素3 U/kg,葡萄糖1.5 g/kg,K 4 mg/kg,Mg2 1.7 mg/kg.②实验评估:分别观察3组动物缺血再灌注2 h,48 h后,血清尿素氮、血糖、血清及肾组织中丙二醛含量以及肾组织超微结构变化.结果:23只动物进入结果分析.①肾缺血再灌注48 h后,缺血再灌注组血清尿素氮含量显著高于对照组(P＜0.01),缺血再灌注胰岛素处理组与对照组差异无显著性意义(P＞0.05).②缺血再灌注组血清及肾组织中丙二醛含量显著高于对照组(P＜0.05),缺血再灌注胰岛素处理组丙二醛含量显著低于缺血再灌注组(P＜0.05).③缺血再灌注2 h后,3组动物血糖均较术前增高,但以缺血再灌注组增高更为显著,与对照组比较差异具有显著性意义(P＜0.05),缺血再灌注胰岛素处理组与对照组差异无显著性意义(P＞0.05).④对照组肾组织超微结构正常,缺血再灌注组肾组织呈变性和坏死改变,缺血再灌注胰岛素处理组肾组织轻度变性.结论:Mg2 ,K 可协同胰岛素减轻家兔急性缺血再灌注性肾损伤,其作用途径可能和降低血糖、抗自由基损伤、改善能量代谢、减轻钙超载、防止低血钾等因素有关.     

Lysis of human fibroblast colony-forming cells and endothelial cells by monoclonal antibody (6-19) and complement

The murine IgG2a monoclonal antibody 6-19 binds to a wide variety of nonhematopoietic cells including human marrow-derived stromal cells but does not bind to marrow or peripheral blood cells. We studied the effects of this antibody and rabbit complement on marrow cells. Fibroblast colonies were eliminated from light density marrow cells by a single incubation with monoclonal antibody 6-19 and complement. The growth and composition of granulocytic and erythroid colonies were unaffected. Specific complement mediated cytotoxicity of the antibody was confirmed on passaged human fibroblasts derived from marrow (more than 99.6% of fibroblasts are killed by a single treatment). Similar results were obtained with human umbilical cord endothelial cells. In addition, such treatment abolished the initiation of Dexter culture stroma. Incubation of bone marrow cell suspensions with this antibody and complement will allow the study of stroma-free marrow cells in long- term liquid cultures.     

4-酰胺基-4-脱氧-4′-去甲表鬼臼毒素衍生物的合成和抗肿瘤活性

4′-去甲表鬼臼毒素与叠氮酸在三氟化硼乙醚存在下缩合,并经还原得4-氨基-4-脱氧-4′-去甲表鬼臼毒素。该中间体与酸或酸酐反应得相应酰胺化合物24个。经体外筛选,多数化合物抑制L₁₂₁₀和KB细胞活性相当或超过依托泊甙。与相应的醚、酯、胺等类型相比,这一类化合物活性最强。     

Viral nucleic acid stabilization by RNA extraction reagent

In the collection of field materials to test for the presence of arboviruses, samples must be appropriately maintained to detect arboviral nucleic acids. In austere field conditions this is often difficult to achieve because, during routine specimen processing, storage, and shipping viral RNA degradation could result in detection failure. RNA extraction reagents, while used commonly for their intended purpose of stabilizing RNA during the extraction process, have not been assessed fully for their potential to stabilize RNA before extraction. The potential for virus stabilization at varying temperatures and periods of time remains unknown. Accordingly, the ability of buffer AVL (Qiagen, Valencia, CA), an RNA extraction reagent, to stabilize viral suspensions of dengue, Venezuelan equine encephalitis and Rift Valley fever viruses was evaluated. The ability of buffer AVL to stabilize each viral suspension was examined at 32, 20, 4, and −20 °C. RNA in samples placed in buffer AVL was stable for at least 48 h at 32 °C and refrigerating samples prolonged stabilization. Additionally, placing the sample/buffer AVL mixture at either 4 or −20 °C stabilized samples for at least 35 days. When combined with the ability of buffer AVL to inactivate viral samples, this provides the ability to collect and handle potentially infectious samples in a safe way that also provides sample stabilization.     

Differential adhesion of Streptococcus mutans to metallic brackets induced by saliva from caries‐free and caries‐active individuals

Aim: The purpose of this study was to evaluate the influence of saliva obtained from caries‐free and caries‐active individuals on the adhesion rates of Streptococcus mutans to metallic brackets. Methods: The unstimulated whole saliva of four caries‐free (decayed, missing, or filled surfaces = 0) volunteers and four caries‐active (decayed, missing, or filled surfaces >12) patients were collected. The saliva samples from each group were mixed and clarified. Acquired pellicles were formed onto 30 metallic edgewise brackets for premolars for each saliva group. The brackets were put in contact with planktonic cells of Streptococcus mutans ATCC 25175. Adhesion rates were assessed by crystal violet retention technique. Results: A higher streptococcal adhesion pattern (P < 0.00001) was observed on acquired pellicles formed by saliva from caries‐active donors. Conclusions: The results showed that saliva from caries‐active patients tends to increase the mutans adhesion to surfaces, which is a point of concern for orthodontists.     

Non-Occlusive Small Bowel Necrosis in Association with Feeding Jejunostomy After Elective Upper Gastrointestinal Surgery

INTRODUCTION

Non-occlusive small bowel necrosis (NOSBN) has been associated with early postoperative enteral feeding. The purpose of this study was to determine the incidence of this complication in an elective upper gastrointestinal (GI) surgical patient population and the influence of both patient selection and type of feeding jejunostomy (FJ) inserted, based on the experience of two surgical units in affiliated hospitals.

PATIENTS AND METHODS

The records were reviewed of 524 consecutive patients who underwent elective upper GI operations with insertion of a FJ for benign or malignant disease between 1997 and 2006. One unit routinely inserted needle catheter jejunostomies (NCJ), whilst the other selectively inserted tube jejunostomies (TJ).

RESULTS

Six cases of NOSBN were identified over 120 months in 524 patients (1.15%), with no difference in incidence between routine NCJ (n = 5; 1.16%) and selective TJ (n = 1; 1.06%). Median rate of feeding at time of diagnosis was 105 ml/h (range, 75–125 ml/h), and diagnosis was made at a median of 6 days (range, 4–18 days) postoperatively. All patients developed abdominal distension, hypotension and tachycardia in the 24 h before re-exploratory laparotomy. Five patients died and one patient survived.

CONCLUSIONS

The understanding of the pathophysiology of NOSBN is still rudimentary; nevertheless, its 1% incidence in the present study does call into question its routine postoperative use especially in those at high risk with an open abdomen, planned repeat laparotomies or marked bowel oedema. Patients should be fully resuscitated before initiating any enteral feeding, and feeding should be interrupted if there is any evidence of feed intolerance.