Particulate endocytosis mediates biological responses of human mesenchymal stem cells to titanium wear debris.

Continual loading and articulation cycles undergone by metallic (e.g., titanium) alloy arthroplasty prostheses lead to liberation of a large number of metallic debris particulates, which have long been implicated as a primary cause of periprosthetic osteolysis and postarthroplasty aseptic implant loosening. Long-term stability of total joint replacement prostheses relies on proper integration between implant biomaterial and osseous tissue, and factors that interfere with this integration are likely to cause osteolysis. Because multipotent mesenchymal stem cells (MSCs) located adjacent to the implant have an osteoprogenitor function and are critical contributors to osseous tissue integrity, when their functions or activities are compromised, osteolysis will most likely occur. To date, it is not certain or sufficiently confirmed whether MSCs endocytose titanium particles, and if so, whether particulate endocytosis has any effect on cellular responses to wear debris. This study seeks to clarify the phenomenon of titanium endocytosis by human MSCs (hMSCs), and investigates the influence of endocytosis on their activities. hMSCs incubated with commercially pure titanium particles exhibited internalized particles, as observed by scanning electron microscopy and confocal laser scanning microscopy, with time-dependent reduction in the number of extracellular particles. Particulate endocytosis was associated with reduced rates of cellular proliferation and cell-substrate adhesion, suppressed osteogenic differentiation, and increased rate of apoptosis. These cellular effects of exposure to titanium particles were reduced when endocytosis was inhibited by treatment with cytochalasin D, and no significant effect was seen when hMSCs were treated only with conditioned medium obtained from particulate-treated cells. These findings strongly suggest that the biological responses of hMSCs to wear debris are triggered primarily by the direct endocytosis of titanium particulates, and not mediated by secreted soluble factors. In this manner, therapeutical approaches that suppress particle endocytosis could reduce the bioreactivity of hMSCs to particulates, and enhance long-term orthopedic implant prognosis by minimizing wear-debris periprosthethic osteolysis.     

Changes in immune regulation in response to examination stress in atopic and healthy individuals

BACKGROUND: Stress can aggravate the allergic inflammation, but determinants of disturbed immune regulation are largely unknown. OBJECTIVE: To determine systemic immunological, local inflammatory and functional airway responses to stress in healthy and atopic individuals. METHODS: Forty-one undergraduate students, 22 with allergy of whom 16 had asthma, and 19 healthy controls, were studied in a low-stress period and in association with a large exam. Subjects completed questionnaires on stress and health behaviours, underwent lung function tests, bronchial methacholine challenge, measurements of exhaled nitric oxide and urine cortisol. Blood cells were phenotyped, and cytokines from mononuclear blood cells were analysed. RESULTS: Perceived stress and anxiety increased in both groups during the exam period while cortisol increased only in the atopy group. Cytokine production decreased broadly in response to stress in both groups, which was paralleled by an increase in the proportion of regulatory T cells (CD4(+)CD45RO(+)CD25(bright)). Interestingly, atopic individuals, but not controls, reacted with a decreased T-helper type 1/T-helper type 2 (Th1/Th2) ratio and a decrease in natural killer (NK) cell numbers in response to stress. In control subjects only, exhaled nitric oxide decreased and forced expiratory volume in one second increased during stress. CONCLUSION: Atopic and non-atopic subjects shared some immune changes in response to stress, such as a dramatic decline in cytokines and an increase in the number of regulatory T cells in peripheral blood. However, other stress-induced immune changes were unique to atopic individuals, such as a skewed Th1/Th2 ratio and reduced NK cell numbers, indicating that some pathogenic mechanisms in atopics may be more strongly affected by stress than others.     

针刺对实验性脑缺血作用机理的研究进展

缺血性脑血管疾病是一个非常复杂的病理生理过程 ,是多种机制共同作用的结果。本文从针刺对实验性脑缺血在脑组织形态学改变、血液流变学、脑微循环等方面的研究进展作一综述。     

Risky Sexual Behavior Among Street Children,Adolescents, and Young People Living on the street in southern Brazil

Although adolescents living on the street tend to have unprotected sex with many partners and substance abuse, little is known about this reality in Brazil. To estimate the prevalence and factors associated with risky sexual behavior among children and adolescents living on the street in Porto Alegre and Rio Grande. A cross-sectional study was carried out using the Respondent-Driven Sampling (RDS) sampling method to quickly and efficiently access populations of difficult access. Poisson regression with robust adjustment of variance was used in the multivariate analysis. The sample consisted of 231 participants aged 10–21 years. Most were male and aged 16- 21 years. More than half (66.7%) of the respondents did not have a school bond, and 64.5% did not live with the family. Half of the sample had been living on the street for at least four years, spending 15 h or more on the street. Most (86.6%) responded that they had already used illicit drugs in their lives, and unprotected sex prevalence was 61.9%. The variables independently associated with unprotected sex were years living on the street, hours spent on the street, having a steady partner, illicit drug use, and sexual intercourse without a condom under the influence of drugs. The high prevalence of unprotected sex points to the need for intervention policies for this population to prevent the main risk factors.

     

微信干预对青光眼患者体力活动量的影响

观察利用微信干预增加青光眼患者体力活动的效果。方法：前瞻性随机对照研究。选择2018年 6-12月于温州医科大学附属眼视光医院门诊确诊的青光眼患者102例作为研究对象。利用Excel生成的随机数随机分为对照组和干预组。对照组患者仅在门诊入组时进行运动宣教,并告知其可增加每天的运动步数;干预组患者入组时进行运动宣教,告知其可增加每天的运动步数的同时,加入微信群进行运动提醒干预。所有患者均需利用运动监测仪器完成基线1周和随访1个月的体力活动监测。采用卡方检验、独立样本t检验、Mann-Whitney U检验、配对t检验及Wilcoxon符号秩检验进行数据分析。结果：排除30例基线运动量较大（步数>12 000步/d）、依从性不好及其他原因失访的患者,最终纳入72例（对照组42例,干预组30例）。干预组患者干预后的步数（t=4.94,P<0.001）,运动消耗的卡路里（Z=-2.87,P=0.004）,代谢当量（Z=-3.30,P=0.001）,中等强度体力活动时间（Z=-2.89, P=0.004）,高强度体力活动时间（t=2.57,P=0.016）及中高强度体力活动时间（Z=-3.01,P=0.003）均较基线增加;轻度体力活动时间（t=-2.14,P=0.041）和久坐静止不动次数较干预前减少（t=-2.76, P=0.022）。对照组随访的步数也较基线增加（t=3.29,P<0.001）,轻度体力活动时间较基线减少（t=-2.57,P=0.014）。另外,干预组的高强度体力活动时间增加量（随访-基线）（Z=-3.04,P=0.002）和超高强度体力活动时间增加量（Z=-2.06,P=0.040）明显高于对照组,差异均有统计学意义。结论：微信干预可以增加青光眼患者的每天运动步数和中高强度体力活动时间,减少患者的轻度体力活动时间和久坐静止次数。     

Hypertension in Developing Countries

The past 2 decades have seen a considerable global increase in cardiovascular disease, with hypertension remaining by far the most common. More than one-third of adults in Africa are hypertensive; as in the urban populations of most developing countries. Being a condition that occurs with relatively few symptoms, hypertension remains underdetected in many countries; especially in developing countries where routine screening at any point of health care is grossly underutilized. Because hypertension is directly related to cardiovascular disease, this has led to hypertension being the leading cause of adverse cardiovascular outcomes, as a result of patients living, often unknowingly, with uncontrolled hypertension for prolonged periods of time. In Africa, hypertension is the leading cause of heart failure; whereas at global levels, hypertension is responsible for more than half of deaths from stroke, just less than half of deaths from coronary artery disease, and for more than one-tenth of all global deaths. In this review, we discuss the escalating occurrence of hypertension in developing countries, before exploring the strengths and weaknesses of different measures to control hypertension, and the challenges of adopting these measures in developing countries. On a broad level, these include steps to curb the ripple effect of urbanization on the health and disease profile of developing societies, and suggestions to improve loopholes in various aspects of health care delivery that affect surveillance and management of hypertension. Furthermore, we consider how the industrial sectors' contributions toward the burden of hypertension can also be the source of the solution.     

Hygiene practices in abattoir and slaughter slab,determinants and assessment of abattoir and slaughter slab facilities in Abakaliki,Ebonyi State South-East Nigeria

BackgroundWorkers in slaughterhouses engaging in unhygienic practices create conducive environments for zoonoses and meat contamination. Knowledge of hygiene practices and their determinants provides evidence for the design of targeted interventions.ObjectivesWe investigated knowledge and determinants of hygiene practices among workers in slaughterhouses and assessed slaughterhouse facilities in Abakaliki.MethodsWorkers in the Central Meat Market abattoir and Slaughter slab Abakaliki were interviewed in a cross-sectional quantitative study to ascertain their knowledge and hygiene practices while abattoir facilities were assessed using a checklist. Associations were analysed with Chi-square while predictors were determined using binary logistic model.ResultsWe interviewed 188 workers 75.5% and 85.6% of whom had good knowledge and good hygiene practices respectively. However, hand-washing before and after handling meat (44.1%), cleaning work surfaces with soap and water (45.2%) and sanitary disposal of waste (6.9%) were suboptimal. Knowledge of good hygiene practice was a predictor of good hygiene practice (AOR: 4.6, 95% CI: 2.0–11.3, p=0.001). Well water and borehole were present in both slaughterhouses and cold rooms were available in Central Meat market abattoir.ConclusionsThe level of good knowledge was high and this was a determinant of good hygienic practices. Training on hygiene practices is recommended to prevent meat contamination and zoonoses.     

Surgical challenges in the treatment of advanced cases of ameloblastoma in the developing world: The authors’ experience

Total mandibulectomy was carried out in 32 patients with extensive oro-facial lesions histologically diagnosed as ameloblastoma in four specialist centres in south-eastern Nigeria from January 2001 to December 2006. All the patients presented at an advanced stage with the whole mandible affected so the treatment of choice was total mandibulectomy. The patients gave informed consent for surgery. The standard surgical procedure was the same in all cases and was performed by the same surgeons. Of the 32 mandibles removed, there were 13 male (41%) and 19 female (59%) patients, giving a male-to-female ratio of 1:1.6. Three (9%) patients died due to problems relating to anaesthesia while five (16%) had postsurgical-related psychosomatic problems. Generally, the postoperative recovery was characterized by reduction in the quality of life of these patients because immediate jaw reconstruction was not feasible. This article highlights the challenges in the surgical management of advanced cases of ameloblastoma in the developing world and proposes a middle ground for professional interactions and exchange programmes among oral and maxillofacial surgeons across the world to assist poorer countries in the management of these advanced cases of oro-facial tumours.