Quantitative differences in developmental profiles of spontaneous activity in cortical and hippocampal cultures

Background

Neural circuits can spontaneously generate complex spatiotemporal firing patterns during development. This spontaneous activity is thought to help guide development of the nervous system. In this study, we had two aims. First, to characterise the changes in spontaneous activity in cultures of developing networks of either hippocampal or cortical neurons dissociated from mouse. Second, to assess whether there are any functional differences in the patterns of activity in hippocampal and cortical networks.

Results

We used multielectrode arrays to record the development of spontaneous activity in cultured networks of either hippocampal or cortical neurons every 2 or 3 days for the first month after plating. Within a few days of culturing, networks exhibited spontaneous activity. This activity strengthened and then stabilised typically around 21 days in vitro. We quantified the activity patterns in hippocampal and cortical networks using 11 features. Three out of 11 features showed striking differences in activity between hippocampal and cortical networks: (1) interburst intervals are less variable in spike trains from hippocampal cultures; (2) hippocampal networks have higher correlations and (3) hippocampal networks generate more robust theta-bursting patterns. Machine-learning techniques confirmed that these differences in patterning are sufficient to classify recordings reliably at any given age as either hippocampal or cortical networks.

Conclusions

Although cultured networks of hippocampal and cortical networks both generate spontaneous activity that changes over time, at any given time we can reliably detect differences in the activity patterns. We anticipate that this quantitative framework could have applications in many areas, including neurotoxicity testing and for characterising the phenotype of different mutant mice. All code and data relating to this report are freely available for others to use.     

Obesity and recurrent intervertebral disc prolapse after lumbar microdiscectomy

Introduction

The primary aim of this study was to investigate the relationship between obesity and recurrent intervertebral disc prolapse (IDP) following lumbar microdiscectomy.

Methods

A retrospective review of case notes from 2008 to 2012 was conducted for all patients who underwent single level lumbar microdiscectomy performed by a single surgeon. All patients were followed up at two weeks and six weeks following surgery, and given an open appointment for a further six months.

Results

A total of 283 patients were available for analysis: 190 (67%) were in the non-obese group and 93 (32.9%) in the obese group. There was no statistical difference in postoperative infection, dural tear or length of stay between the non-obese and obese groups. Recurrent symptomatic IDP was seen in 27 patients (9.5%) confirmed by magnetic resonance imaging. Nineteen (10.0%) were in the non-obese group and eight (8.6%) in the obese group (p>0.8).

Conclusions

In our study, obesity was not a predictor of recurrent IDP following lumbar microdiscectomy. Our literature review confirmed that this study reports the largest series to date analysing the relationship between obesity and recurrent IDP following lumbar microdiscectomy in the British population.     

The Presentation and Outcome of HIV-related Disease in Nairobi

The range of clinical presentations of HIV-related disease inAfrica has not been adequately described, despite the fact thatmany hospitals have to rely heavily on clinical diagnosis. Sixhundred adult medical patients seen in the Casualty Departmentof the main Government hospital in Nairobi were enrolled ina study of the presentation and outcome of HIV-related disease:506 of these patients were admitted, of whom 19 per cent (95)were HIV seropositive. The remaining 94 were dealt with as outpatients:11 percent (10) of these were seropositive. A history of priortreatment for sexually transmitted disease and, if male, beinguncircumcised, were associated with being seropositive. Threepresentations were strongly associated with HIV infection: acutefever with no focus except the gastrointestinal tract (entericfever-like illness), acute cough with fever (community-acquiredpneumonia) and chronic diarrhoea with wasting. The WHO clinicalcase definition (CCD) for AIDS missed a substantial amount ofHIV-related morbidity (sensitivity 39 per cent) and misidentifiedmany seronegative patients (positive predictive value 59 percent). In comparison with the Centers for Disease Control surveillancedefinition for AIDS, the CCD was specific (91 per cent) andsensitive (79 per cent) but only had a positive predictive valuesof 30 per cent: the CCD may therefore be a poor surveillancetool for AIDS. Seropositive patients were much more likely todie than were seronegative patients (39 per cent vs. 15 percent mortality). Enteric fever-like illness was the presentationwhich most commonly proved fatal. A wider spectrum of diseaseis associated with underlying HIV immunosuppression than haspreviously been described in Africa.     

Administration of interleukin-6 stimulates multilineage hematopoiesis and accelerates recovery from radiation-induced hematopoietic depression

Hematopoietic depression and subsequent susceptibility to potentially lethal opportunistic infections are well-documented phenomena following radiotherapy. Methods to therapeutically mitigate radiation-induced myelosuppression could offer great clinical value. In vivo studies in our laboratory have demonstrated that interleukin-6 (IL-6) stimulates pluripotent hematopoietic stem cell (CFU-s), granulocyte-macrophage progenitor cell (GM-CFC), and erythroid progenitor cell (CFU-e) proliferation in normal mice. Based on these results, the ability of IL- 6 to stimulate hematopoietic regeneration following radiation-induced hematopoietic injury was also evaluated. C3H/HeN female mice were exposed to 6.5 Gy 60Co radiation and subcutaneously administered either saline or IL-6 (1,000 micrograms/kg) on days 1 through 3 or 1 through 6 postexposure. On days 7, 10, 14, 17, and 22, femoral and splenic CFU-s, GM-CFC, and CFU-e contents and peripheral blood white cell, red cell, and platelet counts were determined. Compared with saline treatment, both 3-day and 6-day IL-6 treatments accelerated hematopoietic recovery; 6-day treatment produced the greater effects. For example, compared with normal control values (N), femoral and splenic CFU-s numbers in IL-6-treated mice 17 days postirradiation were 27% N and 136% N versus 2% N and 10% N in saline-treated mice. At the same time, bone marrow and splenic GM-CFC values were 58% N and 473% N versus 6% N and 196% N in saline-treated mice; bone marrow and splenic CFU-e numbers were 91% N and 250% N versus 31% N and 130% N in saline-treated mice; and peripheral blood white cell, red cell, and platelet values were 210% N, 60% N, and 24% N versus 18% N, 39% N, and 7% N in saline- treated mice. These studies demonstrate that therapeutically administered IL-6 can effectively accelerate multilineage hematopoietic recovery following radiation-induced hematopoietic injury.     

主动脉弓钙化影响因素的调查与分析

目的 探讨生活习惯及生理生化因素对主动脉弓钙化(AAC)的影响.方法 收集广州生物库队列研究第一、二期的研究对象20430名,年龄50～85岁的基线资料,体格检查、实验室检查和胸部X线的AAC诊断结果及详细的问卷调查数据;用logistic回归分析某些生活习惯及生理生化因素与AAC患病率之间的关系.结果 (1)2名高级放射诊断医师独立阅片对AAC诊断符合率为85%,Kappa值为0.68(P<0.01),显示AAC诊断是可靠的;(2)除血压外,男女性在某些生理生化特征上有明显差别(P<0.05);(3)年龄、吸烟、LDL-C及高血压是男女性患AAC的危险因素(P<0.01),其OR值(95%CI):年龄男性为1.11(1.10～1.12),女性1.12(1.12～1.13);吸烟男性为1.31(1.17～1.47),女性1.31(1.09～1.57);LDL-C男性为1.16(1.06～1.27),女性为1.38(1.22～1.56);高血压男性为1.33(1.18～1.50),女性为1.27(1.18～1.38);女性患糖尿病增加患AAC的风险(P<0.001),其OR值(95%CI)为1.38(1.22～1.56).结论 年龄、吸烟、高血压、LDL-C是患AAC的危险因素,糖尿病增加女性患AAC的风险.     

The effects of dietary hempseed on cardiac ischemia/reperfusion injury in hypercholesterolemic rabbits

BACKGROUND: Hempseed is a novel functional food that contains several health-promoting polyunsaturated fatty acids (PUFAs). PUFAs, such as those found in flaxseed and fish, have been shown to protect the heart against arrhythmias following ischemia/reperfusion. OBJECTIVE: TO INVESTIGATE THE POTENTIAL OF DIETARY HEMPSEED AS A CARDIOPROTECTIVE AGENT AGAINST GLOBAL ISCHEMIA AND SUBSEQUENT REPERFUSION BY ASSESSING SEVERAL MEASUREMENTS OF CARDIAC PERFORMANCE: QT interval duration, left ventricular pressure, arrhythmia incidence and arrhythmia duration. METHODS: MALE NEW ZEALAND WHITE RABBITS WERE FED ONE OF SIX DIETS: a control diet; or one supplemented with 10% hempseed, 10% delipidated hempseed, 0.5% cholesterol, 0.5% cholesterol plus 10% hempseed or 5% coconut oil. After eight weeks on their respective diets, the hearts were excised and subjected to 30 min of global ischemia and 45 min of reperfusion. Electrocardiogram traces were recorded throughout the experiment and were subsequently analyzed for QT interval duration, left ventricular pressure, arrhythmia incidence and arrhythmia duration. Plasma and cardiac tissue were analyzed for fatty acid content and composition. RESULTS: Cholesterol-fed animals exhibited significantly higher PUFA levels in their plasma, but this did not directly translate into higher PUFA levels in their cardiac fractions. There were no significant differences among the groups in the incidence or duration of ischemia-derived arrhythmias. During reperfusion, there was a significant decrease in the incidence of fibrillation in the hearts obtained from cholesterol-fed and hempseed- plus cholesterol-fed rabbits compared with the hearts from delipidated hempseed-fed rabbits. CONCLUSIONS: Dietary hempseed induced limited beneficial effects on cardiac function during ischemia/reperfusion challenge. The present study does not support the use of dietary hempseed to protect the heart during ischemic insult in this experimental model.     

Unplanned readmissions after primary total knee arthroplasty in Korean patients: Rate,causes, and risk factors

Background

Unplanned hospital readmissions are indicators of the quality and performance of a health care system, but data on early readmission after primary total knee arthroplasty (TKA) in the Asian population are limited. The purpose of this study was to determine the causes, risk factors, and rate of unplanned readmission after primary TKA at a single institution in Korea.

Surgical treatment of proximal humerus fractures using PHILOS plate

Objective：To evaluate functional outcome and complications of open reduction and internal fixation with proximal humeral internal locking system （PHILOS） plate for proximal humerus fractures.Methods：We reviewed 51 patients who underwent open reduction and internal fixation with PHILOS plate between the years 2007 to 2012.There were 35 men and 16 women with a mean age of 38 years （range 24-68）.There were 41 patients in the age group of ＜60 years and 10 patients in the age group of ＞60 years.According to Neer classification system,8,15 and 23 patients had 2-part,3-part,and 4-part fractures,respectively and 5 patients had 4-part fracture dislocation.All surgeries were carried out at our tertiary care trauma centre.Functional evaluation of the shoulder at final follow-up was done using Constant-Murley score.Results：The mean follow-up period was 30 months （range 12-44 months）.Two patients were lost to followup.Of the remaining 49 patients,all fractures were united clinically and radiologically.The mean time for radiological union was 12 weeks （range 8-20 weeks）.At the final follow-up the mean Constant-Murley score was 79 （range 50-100）.The results were excellent in 25 patients,good in 13 patients,fair in 6 patients and poor in 5 patients.During the follow-up,four cases of varus malunion,one case of subacromial impingement,one case of deep infection,one case of intraarticular screw penetration and one case of failure of fixation were noted.No cases of avascular necrosis,hardware failure,locking screw loosening or nonunion were noted.Conclusion：PHILOS provides stable fixation in proximal humerus fractures.To prevent potential complications like avascular necrosis,meticulous surgical dissection to preserve vascularity of humeral head is necessary.