Pain and Effusion and Quadriceps Activation and Strength

Context:

Quadriceps dysfunction is a common consequence of knee joint injury and disease, yet its causes remain elusive.

Objective:

To determine the effects of pain on quadriceps strength and activation and to learn if simultaneous pain and knee joint effusion affect the magnitude of quadriceps dysfunction.

Design:

Crossover study.

Setting:

University research laboratory.

Patients or Other Participants:

Fourteen (8 men, 6 women; age = 23.6 ± 4.8 years, height = 170.3 ± 9.16 cm, mass = 72.9 ± 11.84 kg) healthy volunteers.

Intervention(s):

All participants were tested under 4 randomized conditions: normal knee, effused knee, painful knee, and effused and painful knee.

Main Outcome Measure(s):

Quadriceps strength (Nm/kg) and activation (central activation ratio) were assessed after each condition was induced.

Results:

Quadriceps strength and activation were highest under the normal knee condition and differed from the 3 experimental knee conditions (P < .05). No differences were noted among the 3 experimental knee conditions for either variable (P > .05).

Conclusions:

Both pain and effusion led to quadriceps dysfunction, but the interaction of the 2 stimuli did not increase the magnitude of the strength or activation deficits. Therefore, pain and effusion can be considered equally potent in eliciting quadriceps inhibition. Given that pain and effusion accompany numerous knee conditions, the prevalence of quadriceps dysfunction is likely high.Key Words: arthrogenic muscle inhibition, central activation failure, voluntary activation, muscles

Key Points

• Knee pain and effusion resulted in arthrogenic muscle inhibition and weakness of the quadriceps.
• The simultaneous presence of pain and effusion did not increase the magnitude of quadriceps dysfunction.
• To reduce arthrogenic muscle inhibition and improve muscle strength, clinicians should employ interventions that target removing both pain and effusion.

Quadriceps weakness is a common consequence of traumatic knee joint injury^1,2 and chronic degenerative knee joint conditions.^3,4 Arthrogenic muscle inhibition (AMI), a neurologic decline in muscle activation, results in quadriceps weakness and hinders rehabilitation by preventing gains in strength.⁵ The inability to reverse AMI and restore muscle function can lead to decreased physical abilities,⁶ biomechanical deficits,⁷ and possibly reinjury.⁵ Furthermore, researchers^8,9 have suggested that quadriceps weakness resulting from AMI may place patients at risk for developing osteoarthritis in the knee. In light of the substantial influence of quadriceps AMI on these clinically relevant outcomes, we need to improve our understanding of the factors that contribute to this neurologic decline in muscle activity so efforts to target and reverse it can be implemented and gains in strength can be achieved more easily.Joint injury and disease are accompanied by numerous sequelae (ie, pain, swelling, tissue damage, inflammation), so ascertaining which one ultimately leads to neurologic muscle dysfunction is difficult. Whereas a joint effusion can result in AMI,^10–12 the effects of pain are less understood despite many clinicians attributing AMI to pain. Using techniques that introduce knee pain without accompanying injury may provide insights into the role of pain in eliciting AMI.The degree of knee joint damage may play a role in the quantity of AMI that manifests. Hurley et al^13,14 demonstrated that quadriceps AMI, measured using an interpolated-twitch technique, was greater in patients with extensive traumatic knee injury (eg, fractured tibial plateau, ruptured medial collateral ligament, and medial meniscectomy) than patients with isolated joint trauma (ie, isolated anterior cruciate ligament [ACL] rupture). Similarly, patients with more knee joint symptoms (ie, greater number of symptoms and increased severity of symptoms) may present with greater magnitudes of quadriceps inhibition. Recently, investigators¹⁵ have suggested that patients with more pain display less quadriceps strength, supporting this tenet. Given that effusion and pain often present simultaneously with joint injuries and diseases, such as ACL injury and osteoarthritis, examining both the isolated and cumulative effects of these sequelae appears warranted to determine if they influence the magnitude of muscle inhibition.Experimental joint-effusion and pain models are safe and effective experimental methods that allow for the isolated examination of their effects on muscle function. The effusion model, whereby sterile saline is injected directly into the knee joint capsule,⁷ produces a clinically relevant magnitude of the joint effusion that may be present with traumatic injury. Effusion is thought to activate group II afferents responding to stretch or pressure,^16–18 which in turn may facilitate group Ib interneurons and result in quadriceps AMI.⁵ The pain model involves injecting hypertonic saline into the infrapatellar fat pad to produce anteromedial knee pain similar to that described in patients with patellofemoral pain syndrome.¹⁹ Pain is considered to initiate AMI through activation of group III and IV afferents that act as nocioceptors to signal damage or potential damage to joint structures.^16–18 The firing of these afferents then may lead to facilitation of group Ib interneurons, the flexion reflex, or the gamma loop, ultimately resulting in quadriceps inhibition.²⁰ Thus, these models allow us to create symptoms that are associated with knee injury and have the added benefit of providing a way to examine their effects in isolation.Therefore, the purpose of our study was to determine the effects of pain on quadriceps strength and activation and to learn if simultaneous pain and knee joint effusion would affect the magnitude of quadriceps dysfunction. We hypothesized that pain alone would result in quadriceps inhibition and that the magnitude of inhibition would be greater when effusion and pain were present simultaneously.     

即早基因c-fos与脑血管病及学习记忆

即早基因c-fos是广泛存在于原核细胞和真核细胞的高度保守基因.在正常情况下,c-fos基因参与细胞生长、分化、信息传递、学习和记忆等生理过程,而在病理情况下c-fos基因表达及调控变化与多种疾病的发生和发展有关.C-fos在中枢神经系统的某些部位可有基础水平的表达,但表达很低,当受到如脑缺血、脑出血、痫性发作、应激等刺激后,其在数十分钟内做出反应,在对外界刺激-转录耦联的信忠传递过程中起着核内第三信使的重要作用.     

Opportunities and challenges in the prevention and control of cancer and other chronic diseases: children's diet and nutrition and weight and physical activity

OBJECTIVE: The purpose of this article is to review the role of behavioral research in disease prevention and control, with a particular emphasis on lifestyle- and behavior-related cancer and chronic disease risk factors--specifically, relationships among diet and nutrition and weight and physical activity with adult cancer, and tracking developmental origins of these health-promoting and health-compromising behaviors from childhood into adulthood. METHOD: After reviewing the background of the field of cancer prevention and control and establishing plausibility for the role of child health behavior in adult cancer risk, studies selected from the pediatric published literature are reviewed. Articles were retrieved, selected, and summarized to illustrate that results from separate but related fields of study are combinable to yield insights into the prevention and control of cancer and other chronic diseases in adulthood through the conduct of nonintervention and intervention research with children in clinical, public health, and other contexts. RESULTS: As illustrated by the evidence presented in this review, there are numerous reasons (biological, psychological, and social), opportunities (school and community, health care, and family settings), and approaches (nonintervention and intervention) to understand and impact behavior change in children's diet and nutrition and weight and physical activity. CONCLUSIONS: Further development and evaluation of behavioral science intervention protocols conducted with children are necessary to understand the efficacy of these approaches and their public health impact on proximal and distal cancer, cancer-related, and chronic disease outcomes before diffusion. It is clear that more attention should be paid to early life and early developmental phases in cancer prevention.     

Change and reciprocity in adolescent aggressive and rule-breaking behaviors and parental support and dysfunctional discipline

This study examined how the development of aggressive/rule-breaking behaviors (9-17 years) is related to the development of overreactive and warm parenting, and explored gender differences in development and interrelations. Externalizing was assessed using combined mother/father reports of the Child Behavior Checklist (N = 516). Overreactivity was assessed using self-reports of the Parenting Scale; warmth was measured using self-reports of the Parenting Practices Questionnaire. All constructs were assessed three times across 6 years. The interrelated development of externalizing and parenting was examined by cohort-sequential multigroup latent growth models. Timing of effects was investigated using multigroup cross-lagged models. The results from latent growth models suggest that boys and girls change similarly in the extent to which they show externalizing behaviors, and indicate that mothers and fathers show somewhat different parenting toward boys than girls. No gender differences were found for interrelations between externalizing and parenting. Initial levels of aggression were related to changes in overreactivity and warmth, and vice versa. Changes in externalizing were related to changes in parenting. Cross-lagged models showed that relations between overreactivity and aggression/rule breaking were reciprocal. Together, results from this study show that adolescent externalizing and parenting affect each other in important ways, regardless of the gender of the child or the parent.     

3- and 4-dimethylaminobenzyl acrylate and methacrylate and their polymers

3- and 4-dimethylaminobenzyl acrylates ( 3 and 4 ) and methacrylates ( 1 and 2 ) were prepared and their densities, IR and NMR spectra are recorded. In order to evaluate their reactivity towards benzoyl peroxide, the rate constants of the reaction of benzoyl peroxide with 3- and 4-dimethylaminobenzyl alcohols and 3- and 4-dimethylaminobenzyl acetates were determined. The reactivity of the esters prepared in this work appeared to be weaker than that of an N-aryl-N-alkylaminoalkyl methacrylate. The blocks of homopolymers of these esters and of their copolymers (mole ratio 1:1) with styrene and methyl methacrylate are crosslinked. Both homopolymers and copolymers of 1 and 3 are more stable in polar solvents and on heating than polymers of 2 and 4 . The copolymerization parameters of 1 and 2 with styrene are close to the copolymerization parameters of methyl methacrylate with styrene.     

Tobacco and alcohol and the risk of head and neck cancer

Summary We carried out two case-control studies on the relative risk of head and neck cancer in association with tobacco and alcohol consumption. The first study carried out at the ENT Department of the University hospitals of Heidelberg and Giessen (FRG) comprised 200 male patients with squamous cell cancer of the head and neck and 800 control subjects matched for sex, age, and residential area (1:4 matching design). Of the tumour patients, 4.5% had never smoked, in contrast to 29.5% of the control group. The average tobacco and alcohol consumption of the patients was approximately twice as high as in the control subjects. The highest alcohol and tobacco consumption was observed in patients suffering from oropharyngeal cancer. Tobacco and alcohol increased the risk of head and neck cancer in a dose-dependent fashion and acted as independent risk factors. In heavy smokers (> 60 pack-years) a relative risk of 23.4 (alcohol adjusted) was calculated. Combined alcohol and tobacco consumption showed a synergistic effect. The risk ratio increased more in a multiplicative than in an additive manner. Oral and laryngeal cancer were associated with the highest tobacco-associated risk values. The highest ethanol-associated risk values were associated with oropharyngeal and laryngeal cancer. The second study was carried out at the ENT Department of the University of Heidelberg on 164 males with squamous cell carcinoma of the larynx and 656 control subjects matched for sex, age and residential area (1:4 matching design). Of the cases, 4.2% had never smoked, compared with 28.5% of the control subjects. The risk of laryngeal cancer by tobacco consumption was dose dependent, reaching a maximum value of 9.1 (adjusted for alcohol) for a consumption of more than 50 tobacco-years (TY). The relative risk of laryngeal cancer associated with alcohol intake was also dose dependent, reaching a value of 9.0 (adjusted for tobacco) for a mean daily consumption of more than 75 g alcohol. An analysis of subsite specific risks showed that heavy smokers (> 50 TY) carried a nearly ten times higher risk of supraglottic cancer than of glottic cancer. The risk of supraglottic cancer from alcohol consumption was also higher than that of glottic cancer.     

Beta-endorphin and drug-induced reward and reinforcement

Although drugs of abuse have different acute mechanisms of action, their brain pathways of reward exhibit common functional effects upon both acute and chronic administration. Long known for its analgesic effect, the opioid beta-endorphin is now shown to induce euphoria, and to have rewarding and reinforcing properties. In this review, we will summarize the present neurobiological and behavioral evidences that support involvement of beta-endorphin in drug-induced reward and reinforcement. Currently, evidence supports a prominent role for beta-endorphin in the reward pathways of cocaine and alcohol. The existing information indicating the importance of beta-endorphin neurotransmission in mediating the reward pathways of nicotine and THC, is thus far circumstantial. The studies described herein employed diverse techniques, such as biochemical measurements of beta-endorphin in various brain sites and plasma, and behavioral measurements, conducted following elimination (via administration of anti-beta-endorphin antibodies or using mutant mice) or augmentation (by intracerebral administration) of beta-endorphin. We suggest that the reward pathways for different addictive drugs converge to a common pathway in which beta-endorphin is a modulating element. beta-Endorphin is involved also with distress. However, reviewing the data collected so far implies a discrete role, beyond that of a stress response, for beta-endorphin in mediating the substance of abuse reward pathway. This may occur via interacting with the mesolimbic dopaminergic system and also by its interesting effects on learning and memory. The functional meaning of beta-endorphin in the process of drug-seeking behavior is discussed.     

Stress and coping and behavioral organization

This article presents a new integrative theoretical framework for stress and coping centered on the concept of behavioral organization and the notions that stress disorganizes behavior and coping aims at reorganizing it. Functional analysis of behavioral organization leads to identification of four core domains of control and to a functional classification of types of stressful conditions, types of negative emotions, and types of coping functions linked directly to the control domains. The control domains are represented cognitively by four postulated kinds of beliefs or views people hold with respect to undertaking an action: performance, process, prospect, and profit beliefs. The four basic control beliefs form the core of the present coping belief model of coping. Recognition of the underlying structure of behavior, and of functional categories of stress and coping related to it, can advance theory and research on stress and coping by enriching its psychological content, improving research designs, and leading to reexamination, reinterpretation, and integration of findings existing in the literature that presently are fragmented and unconnected.     

Postinfectious immunodeficiency and autoimmunity: pathogenic and clinical values and implications

Autoimmunity is still a mystery of clinical immunology and medicine as a whole. The etiology and pathogenesis of autoimmune disorders remain unclear and, thus, are assessed as a balance between hereditary predisposition, triggering factors and the appearance of autoantibodies and/or self-reactive T cells. Among the immunological armamentarium, molecular mimicry, based on self-reactive T- and B-cell activation by cross-reactive epitopes of infectious agents, is of special value. Hypotheses regarding the possible involvement of molecular mimicry in the development of postinfectious autoimmunity are currently very intriguing. They provide new approaches for identifying etiological agents that are associated with postinfectious autoimmunity, paired microbial- and tissue-linked epitopes targeted for autoimmune reaction determination, postinfectious autoimmunity pathogenesis recognition and specific prevention, and therapy for autoimmune disorder development.     

microRNA与肿瘤侵袭转移

microRNA (miRNA)是一类长度为17~25 nt的单链非编码RNA,通过与靶基因mRNA互补位点的结合在转录后水平调控靶基因的表达.miRNA作为调控基因表达的重要分子在肿瘤侵袭转移中的作用越来越受到重视,阐明miRNA在肿瘤侵袭和转移中的作用机制具有重要的理论意义,同时也可以为肿瘤的诊断和治疗提供新方法.文章综述了miRNA在鼻咽癌、乳腺癌、肺癌、肝癌、结直肠癌和前列腺癌侵袭转移过程中作用机制的研究进展.     

PTEN与信号转导及肿瘤

ＴＥＮ[1] (ｐｈｏｓｐｈａｔａｓｅａｎｄｔｅｎｓｉｎｈｏｍｏｌｏｇｙｄｅｌｅｔｅｄｏｎｃｈｒｏｍｏｓｏｍｅｔｅｎ)又名ＭＭＡＣ1 [2 ] (ｍｕｔａｔｅｄｉｎｍｕｔｉｐｌｙａｄａｎｃｅｄｃａｎｃｅｒ 1 )和ＴＥＰ1 [3 ] (ＴＧＦ -βｒｅｇｕｌａｔｅｄａｎｄｅｐｉｔｈｅｌｉａｌｃｅｌｌ -ｒｉｃｈｅｄｐｈｏｓｐｈａｔａｓｅ 1 ) (以下均称为ＰＴＥＮ) ,是 1 997年由 3个研究小组先后发现的一个具有双特异磷酸酶活性的抑癌基因。ＰＴＥＮ基因异常广泛存在于人类多种恶性肿瘤 ,如恶性神经胶质瘤、前列腺癌、子宫内膜癌、黑色素瘤等…     

Interstitial fluid and lymph formation and transport: physiological regulation and roles in inflammation and cancer

The interstitium describes the fluid, proteins, solutes, and the extracellular matrix (ECM) that comprise the cellular microenvironment in tissues. Its alterations are fundamental to changes in cell function in inflammation, pathogenesis, and cancer. Interstitial fluid (IF) is created by transcapillary filtration and cleared by lymphatic vessels. Herein we discuss the biophysical, biomechanical, and functional implications of IF in normal and pathological tissue states from both fluid balance and cell function perspectives. We also discuss analysis methods to access IF, which enables quantification of the cellular microenvironment; such methods have demonstrated, for example, that there can be dramatic gradients from tissue to plasma during inflammation and that tumor IF is hypoxic and acidic compared with subcutaneous IF and plasma. Accumulated recent data show that IF and its convection through the interstitium and delivery to the lymph nodes have many and diverse biological effects, including in ECM reorganization, cell migration, and capillary morphogenesis as well as in immunity and peripheral tolerance. This review integrates the biophysical, biomechanical, and biological aspects of interstitial and lymph fluid and its transport in tissue physiology, pathophysiology, and immune regulation.     

Omphalocele and gastroschisis and associated malformations

The etiology of gastroschisis and omphalocele is unclear and their pathogenesis is controversial. Because previous reports have inconsistently noted the type and frequency of malformations associated with omphalocele and gastroschisis, we assessed these associated malformations ascertained between 1979 and 2003 in 334,262 consecutive births. Of the 86 patients with omphalocele, 64 (74.4%) had associated malformations. These included patients with chromosomal abnormalities (25, 29.0%); non-chromosomal syndromes including Beckwith-Wiedemann syndrome, Goltz syndrome, Marshall-Smith syndrome, Meckel-Gruber syndrome, Oto-palato-digital type II syndrome, CHARGE syndrome, and fetal valproate syndrome; malformation sequences, including ectopia cordis, body stalk anomaly, exstrophy of bladder, exstrophy of cloaca, and OEIS (Omphalocele, Exstrophy of bladder, Imperforate anus, Spinal defect); malformation complexes including Pentalogy of Cantrell, and non-syndromic multiple congenital anomalies (MCA) (26, 30.2%). Malformations of the musculoskeletal system (31, 23.5%), urogenital system (27, 20.4%), cardiovascular system (20, 15.1%), and central nervous system (12, 9.1%) were the most common other congenital malformations in patients with omphalocele and non-syndromic MCA. Of the 60 patients with gastroschisis, 10 (16.6%) had associated malformations. In contrast to omphalocele, gastroschisis was rarely associated with a complex pattern of malformation, that is, one each (1.7%) with a chromosomal abnormality (trisomy 21), sequence (amyoplasia congenita), unspecified dwarfism, and 7 (11.7%) with MCA. We observed a striking difference in the prevalence of total malformations (74.4% vs. 16.6%, P < 0.001) and specific patterns of malformations associated with omphalocele and gastroschisis which emphasizes the need to evaluate all patients with omphalocele and gastroschisis for possible associated malformations. Malformation surveillance programs should be aware that the malformations associated with omphalocele can be often classified into a recognizable malformation syndrome or pattern (44.2%).     

Modes of reinforcement and gender and culture of experimenter and subject: effects of "alien" and external reinforcement for Japanese and American men and women

In this study, we examined external and "alien" reinforcement (ER and AR. respectively) as a factor in social learning, and studied the combined effects of culture and reinforcement mode. A female (Experiment 1) and a male (Experiment 2) experimenters conducted experimental sessions. Both men and women, who grew up in the same culture as the experimenter, participated and performed the experimental task. A three-way interaction effect of experimenter gender, culture, and reinforcement mode was found on task performance. And the effect was more pronounced for a Japanese experimenter. A female and a male experimenters conducted Experiments 3 and 4, respectively; however participants this time were men and women who grew up in different cultures than the experimenter. Results indicated that the pattern of the subject gender and reinforcement mode interaction effect, when the experimenter was Japanese with American subjects, was exactly opposite to that when the experimenter was American. These experiments showed that AR was as effective for social learning as ER, and that the cultural backgrounds of experimenter and subject influenced AR and ER effectiveness.     

海洛因成瘾与学习记忆

海洛因成瘾是我国发病最高,危害最大的一种成瘾性疾病,而其中枢机制则是解决临床预防和治疗的关键,至今仍不清楚。既往工作表明,学习记忆功能在海洛因成瘾的中枢机制中居于重要的中心环节。本文在总结既往海洛因成瘾研究工作基础上联系学习记忆功能,试图从系统整合层次分析相关领域研究工作的不足和今后工作的发展方向。     

Environmental and occupational stress and autoimmunity

The immune system and the neuroendocrine system machinery modulate each other, including life events-induced stresses and interpersonal conflicts, promoting the synthesis of proinflammatory cytokines, overproduction of which influence behaviour. In addition, the balance of systemic and local pro-inflammatory cytokines to systemic and local anti-inflammatory cytokines, is impaired to such an extent that, in genetically-predisposed individuals, this aberrancy may lead to autoimmune diseases. Occupational stress likely influences their onset. For example, subclinical autoimmune hypothyroidism has been identified in numerous shift-workers of an Italian hospital. Such a threat impacts the policy of health surveillance of the workers and requires dedication of further studies to the relationship between occupational stress and autoimmunity.     

Tissue and blood ferritins and isoferritins

Ferritins which can store excess iron are localised principally in tissue. Ferritins have on apoprotein shell which is composed of 24 sub-units, from 2 types of sub-units: "H" (molecular weight about 21 000) and "L" (molecular weight about 19 000) that assemble in different proportions and give multiple forms. Protein pattern depends on tissue nature. Since 1972, radio-immunology assays have shown very low serum ferritin levels. There is a good correlation between these levels and the amount of storage iron in the body. However it was demonstrated that elevation of serum ferritin could also occur without iron metabolism trouble by various mechanisms.     

类赖氨酰氧化酶2与肿瘤转移和发生

类赖氨酰氧化酶2(lysyl oxidase-like 2,LOXL2)是赖氨酰氧化酶(lysyl oxidase,LOX)基因家族的成员之一,其表达产物能促进胶原沉积.LOXL2的过表达能促进纤维化,并与肿瘤侵袭、转移及不良预后有关.目前大部分学者认为LOXL2是一种转移促进基因,也有实验支持其是一种肿瘤抑制基因.研究发现LOXL2可以通过激活Snail/Ecadherin通路或Src/FAK通路促进转移.LOXL2有望作为肿瘤生物标志物,用于预后判断,成为一个新的治疗靶点.     

贫困大学生自我和谐与自尊的调查分析

目的了解贫困大学生自我和谐、自尊状况以及自我和谐与自尊的相关程度。方法应用自我和谐量表（SCCS）和自尊调查表（SEI）对196名在校贫困大学生进行调查。结果贫困大学生自我和谐量表中3个分量表各均分均低于大学生常模,但自我和谐性低的贫困生占的比例却明显高于常模比例,将SCCS与SEI进行相关比较,高自尊的贫困大学生自我和谐程度也比较高。结论贫困大学生总体的自我和谐性较好,自我和谐性与自尊高低呈正相关。     

Stressors and Child and Adolescent Psychopathology: Measurement Issues and Prospective Effects

This article reviews existing research on the association between stressors and symptoms of psychopathology in children and adolescents with a focus on measurement issues and prospective effects. The first half of the article focuses on the measurement of stressors, emphasizing checklists and interviews. Available measures of stressful experiences are reviewed and critiqued. Results of this review reveal both substantial progress (i.e., development of valid stressor assessment tools) and remaining problems (i.e., inconsistent measurement across studies). The second half of this article reviews studies that have tested for prospective associations between stressors and symptoms of psychopathology in children and adolescents. Studies that have examined the prospective effects of recent or prior stressors on current psychological symptoms, while controlling for prior psychological symptoms, are reviewed. Results overall suggest that stressors predict changes in rates of symptoms of psychopathology in children and adolescents over time. Results also suggest that symptoms of psychopathology predict changes in rates of stressors over time. Implications of these findings are that conclusive evidence now exists for the importance of stressors in the development of child and adolescent psychopathology.