细胞因子对骨骼肌细胞和胰岛β细胞的作用

BACKGROUND: A variety of cytokines such as cytokines, growth factors and inflammatory proteins play an important role in the development of skeletal muscle. OBJECTIVE:To investigate the biological characteristics of a variety of cytokines and their effects on skeletal muscle cells and pancreatic β cells. METHODS: Relevant articles published from 2002 to 2015 were retrieved in CNKI and PubMed databases using the English keywords “cytokines, adiponectin, leptin, visfatin, skeletal muscle cells, pancreatic β cells”. Initially 253 literatures were obtained, and finally 53 eligible literatures were included based on the exclusion criteria. RESULTS AND CONCLUSION: As a fat-specific protein newly found, adiponectin can improve the insulin sensitivity by promoting glucose uptake, storage and utilization in skeletal muscle cells. The activation of muscle satellite cells and skeletal myoblast proliferation are both dependent on leptin, so leptin plays a vital role in the skeletal muscle cell growth and development. Visfatin, a pleiotropic cytokine, widely presents in the skeletal muscle, liver and bone marrow, and participates in the regulation of inflammation and immune function. Furthermore, visfatin contributes to glucose uptake and metabolism in the skeletal muscle, and makes considerable effects on the stress and signal transduction of skeletal muscle cells. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

20 W微波照射骨骼肌卫星细胞的增殖与分化：兔骨折内固定模型研究

BACKGROUND:Low power microwave irradiation has been shown to promote the healing of fractures with internal fixation; however, its action mechanisms on the skeletal muscle around the fracture site are unclear. OBJECTIVE:To study the effects of low power microwave irradiation (20 W) on the proliferation ability of skeletal muscle satellite cells in a rabbit model of femoral fracture with internal fixation. METHODS:Forty male New Zealand rabbits were used to establish femoral fracture followed by internal fixation models, and then were equally randomized into spontaneous recovery and microwave treatment groups. Low power microwave irradiation (20 W) was given for 30 consecutive days in the microwave treatment group on day 4 after modeling, while no microwave irradiation was given in the spontaneous recovery group. Rabbit thigh muscles adjacent to the implant were obtained to isolate skeletal muscle satellite cells. Immunohistochemical staining, hematoxylin-eosin staining and quantitative RT-PCR were used to evaluate the ability of the proliferation and differentiation of skeletal muscle satellite cells. RESULTS AND CONCLUSON: Hematoxylin-eosin staining showed that there was no significant difference in the morphology and histology of skeletal muscle tissues between the spontaneous recovery and microwave treatment groups. However, the relative mRNA expression of MyoG in the cultured skeletal muscle satellite cells in vitro and the number of α-sarcometric actin-postive cells in the microwave treatment group were significantly increased compared with the spontaneous recovery group (P < 0.05). The proliferative ability of skeletal muscle satellite cells was inhibited at the early stage, but not at the later stage. Our results suggest that low power microwave irradiation (20 W) can promote the proliferation and differentiation of skeletal muscle satellite cells around the implant in a rabbit model of femoral fracture with internal fixation, and thereby confirm the efficacy and safety of low power microwave irradiation for the internal fixation of fractures. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

少肌症对骨骼肌的影响、分子机制及其防治

BACKGROUND: There is an urgent need to explore the loss of skeletal muscle mass during aging (sarcopenia), and its molecular mechanisms of action, and prevention and treatment strategies. OBJECTIVE: To summarize the latest progress in molecular mechanisms of sarcopenia, and to provide a fundamental for promoting functional recovery and regeneration of skeletal muscle. METHODS: A computer-based online search was conducted in PubMed and Wanfang databases from 2005 to 2015 to screen the relevant literatures using Chinese and English key words “sarcopenia, skeletal muscle, mechanism, therapy”, respectively. Consequently, 31 eligible literatures were collected, summarized, and analyzed. RESULTS AND CONCLUSION:Sarcopenia is closely correlated with oxidative stress caused by mitochondrial respiratory failure, inhibition of activating factors for regulating satellite cells, reduction in insulin secretion, decreased sensitivity, protein synthesis, and low protein diet. There are common features and molecular mechanisms in sarcopenia and disuse muscle atrophy. Further exploration of exercise and diet strategies for the treatment of sarcopenia is required. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

生长因子对骨骼肌损伤与修复的作用

BACKGROUND: Growth factors involved in the regulation of cellular processes play an important role in the wound healing and tissue regeneration. OBJECTIVE:To elaborate the role of a variety of cellular processes involving growth factors in the repair of skeletal muscle injury, and to provide the references for the treatment and rehabilitation strategies, and the synthesis of biomaterials with growth factor for the skeletal muscle after injury. METHODS: A computer-based online search was conducted in PubMed, Mendeley, Google Scholar, and CNKI databases from 1995 to November 2015 to screen the relevant literatures using the keywords “skeletal muscle, damage repair, insulin-like growth factor, epidermal growth factor, growth factor”. Data screening, processing, and summary were performed. RESULTS AND CONCLUSION: Fifty-one eligible literatures were included. Exercise training promotes the repair and regeneration of the injured skeletal muscle cells and the recovery of the function by activating satellite cells in the sarcolemma and basement membrane to produce the numerous myoblasts. The repair involves the complex biological process regulated by growth factors. Exogenous growth factors up-regulate the mRNA expression of endogenous growth factors, stimulate the proliferation of the myoblasts, accelerate the fusion between myotubes and muscle fibers, promote the repair of skeletal muscle injury, inhibit the formation of scars, thereby enhancing the healing quality. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

神经细胞分泌因子促进骨骼肌细胞生长

BACKGROUND: There is no effective treatment for muscle atrophy caused by peripheral nerve damage. Skeletal muscle cells, a structural unit of muscle contraction, can be used for studies on muscle atrophy when cultured in vitro. OBJECTIVE: To investigate the promotion effect of neuron-secreted factors on the growth of skeletal muscle cells in vitro. METHODS: Skeletal muscle cells primary cultured in vitro were divided into two groups: experimental group with neuron-secreted factors, and control group with common culture medium, respectively. Afterwards, the number of skeletal muscle cells and expression level of alpha actin were detected by hematoxylin-eosin staining and immunohistochemical staining, respectively. RESULTS AND CONCLUSION:The number of skeletal muscle cells and expression level of alpha actin in the experimental group were significantly higher than those in the control group (P < 0.05). In conclusion, neuron-secreted factors have the ability of promoting the growth of skeletal muscle cells and may be helpful for denervated muscle atrophy. Subject headings: Tissue Engineering; Satellite Cells, Skeletal Muscle; Actinin; Neurons; Cells, Cultured 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

转化生长因子β信号与肌肉调控

BACKGROUND: Transforming growth factor-β signaling widely existing in cells mediates cell growth, proliferation, migration, differentiation, and apoptosis. The activation of transforming growth factor-β signaling can result in muscular dystrophy. However, there have been some contradictions regarding the effects of the transforming growth factor-β signaling on muscular dystrophy. OBJECTIVE: To summarize the latest progress in the effects of the transforming growth factor-β signaling on muscle mass and function regulation to provide the solutions for the treatment of muscular dystrophy. METHODS: A computer-based online search was conducted in PubMed and Wanfang databases from 2005 to 2015 to screen the relevant literatures using Chinese and English key words “transforming growth factor-β, muscle, regulation mechanism, treatment”. A total of 102 literatures were retrieved, and 22 eligible literatures were included, summarized, and analyzed. RESULTS AND CONCLUSION: The activation of transforming growth factor-β signaling as a common cause of most muscle disorders promotes the activation of muscle satellite cells, differentiation of myocytes, myoblast infusion, the expression of muscle-specific proteins, and the inhibition of collagen synthesis, which facilitates muscular fibrosis and scar formation. Transforming growth factor-β signaling is involved in Duchenne muscular dystrophy, spinal scoliosis, type I diabetes induced skeletal muscle regenerative disorders, myocardial and cardiac remodeling. The inhibition of transforming growth factor-β signaling may result in incomplete muscle recovery. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

人脐动脉平滑肌细胞培养及转染TFPI基因的实验研究

Objective The aim of the present study is to investigate the effect of tissue factor pathway inhibitor (TFPI) gene on cell cycle of human vascular smooth muscle cells.Methods Human vascular smooth muscle cells were separated from human umbilical artery and identified by immunohistochemical staining.The cells were transfected with various amount of pIRES-TFPI plasmid (1,2,and 3 μg/ml,respectively)and the TFPI expression in the cells were analyzed by RT-PCR.MTT assay was employed to detect the effect of TFPI gene on the proliferation of human vascular smooth muscle cells.Results The proliferation of vascular smooth muscle cells was inhibited in pIRES-TFPI group 5 and 7 days after gene transfection when compared with that of pIRES 1-neo transfection group.Conclusion The overexpression of TFPI gene in human umbilical artery vascular smooth muscle cells may contribute to the suppression of the proliferation of cells by gene transfection.     

骨骼肌生长因子、肌球蛋白及骨骼肌胶原与骨骼肌的损伤与修复

BACKGROUND: Regeneration and repair of injured skeletal muscle are influenced by a variety of factors. Skeletal muscle myosin heavy chain and skeletal muscle collagen content are known to be involved in the repair of injured skeletal muscle. OBJECTIVE: To summarize the changes and roles of skeletal muscle growth factors, myosin, and collagen in the repair of injured skeletal muscle. METHODS: A computer-based online search was conducted in PubMed and Wanfang databases from 2002 to 2015 to screen the relevant literatures. Roles of skeletal muscle growth factors, myosin, and collagen in the repair of injured skeletal muscle was summarized by collecting the data regarding the factors influencing exercise and the repair of injured skeletal muscle, and growth factors involved in the regeneration and repair of injured skeletal muscle. RESULTS AND CONCLUSION: Insulin-like growth factor, fibroblast growth factor and hepatocyte growth factor regulate inflammation after skeletal muscle injury extensively. Myosin heavy chain is considered as a specific marker for skeletal muscle regeneration. Types I and III collagen and fibronectin functioning as a skeleton for skeletal muscle fiber play critical roles in the regeneration and repair of injured skeletal muscle. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

转化生长因子-β在哮喘气道炎症与重塑中的作用

Transforming growth factor-β(TGF-β) was reported to be increased in asthma in some studies. Accumulation of TGF-β in airway promotes smooth muscle cell mitogenesis and hyperplasia, and in-duces fibroblast and myofibroblast and smooth muscle proliferation as well as increase in protein synthesis in connective tissue(such as collagen deposition on the reticular basement membrane). The autocrine induction of collagen expression by smooth muscle may contribute to the thickening of the reticular basement membrane, irre-versible f‘throsis and remodeling seen in the airways in some asthmatics. TGF-β is considered to be a major fi-brogenic cytokine. It can increase smooth muscle mass and lead to severe bronchial obstruction in an asthma at-tack.     

胰酶联合Ⅱ型胶原酶分离培养髓核细胞：培养基中葡萄糖浓度的选择

BACKGROUND: Intervertebral disc degeneration is the pathological basis of degenerative spinal diseases. Studies on the influential factors of intervertebral disc degeneration contribute to the prevention and treatment of degenerative spinal disease. OBJECTIVE: To observe the growth and proliferation of nucleus pulposus cells isolated by trypsin plus type II collagenase digestion in complete medium with different glucose concentrations, exploring the optimal glucose concentration for growth of nucleus pulposus cells. METHODS: Nucleus pulposus cells isolated and cultured by trypsin plus type II collagenase digestion method were observed under an inverted microscope, and the cell number was counted. Morphology of nucleus pulposus cells was observed after hematoxylin-eosin staining and toluidine blue staining. Collagen type II immunoreactivity was detected by immunohistochemical staining combined with immunofluorescent staining. Nucleus pulposus cells were incubated in complete medium containing various glucose concentrations (0, 6.25, 12.5, 17.5, and 25 mmol/L) for 24 hours, and then cell proliferation and apoptosis were determined. RESULTS AND CONCLUSION: The stained nucleus pulposus cells showed polygonal and short spindle, with one or two nuclei. Cellular pseudopod appeared gradually and then became slim with increased passage numbers. The isolated and cultured nucleus pulposus cells positively expressed collagen type II and aggrecan Proliferative activity of nucleus pulposus cells cultured in medium with 17.5 mmol/L glucose was significantly higher than that in medium with 0 and 25 mmol/L glucose (P < 0.05 or P < 0.01). There was no significant difference in cell apoptosis between these groups except for 0 mmol/L glucose (P < 0.05). These results confirm that a large number of nucleus pulposus cells can be harvested by trypsin plus type II collagenase digestion and the optimal glucose concentration is 17.5 mmol/L. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

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.     

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.     

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.     

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.     

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…     

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.     

Muscle strength and serum testosterone,cortisol and SHBG concentrations in middle-aged and elderly men and women

Forty healthy males (M) and females (F) divided into two different age groups i.e. M50 years (range 44–57; n= 9), F50 years (range 43–54; n= 9), M70 years (range 64–73; n= 11) and F70 years (range 63–73; n= 11) volunteered as subjects for examination of muscle cross-sectional area (CSA) and maximal voluntary isometric force production characteristics of the leg extensor muscles and serum androgen and sex hormone binding globulin (SHBG) concentrations. The CSA in the male groups was greatly larger (P < 0.01) than in the female groups and both elderly groups demonstrated slightly (n.s.) smaller values in the CSA than the two middle-aged groups. Maximal force of 2854 ± 452 N in M50 was greater (P < 0.05) than that of 2627 ± 752 N recorded for F50 as well as the force of 2787 ± 843 in M70 was greater (P < 0.001) than that of 1849 ± 295 recorded for F70. The force between F50 and F70 differed significantly (P < 0.05) from each other. The maximal rate of force production in M50 was greater (P < 0.01) than in F50 as well as in M70 greater (P < 0.001) than in F70. Both middle-aged groups demonstrated greater (P < 0.05) values than the respective elderly groups of the same sex. The individual values in the CSA correlated with the values in maximal force both in the middle-aged subjects (r= 0.66; P < 0.01) and in the elderly subjects (r= 0.69; P < 0.01). The mean concentration of serum testosterone in M50 was slightly (n.s.) greater than in M70 and in F50 significantly (P < 0.05) greater than in F70. Serum SHBG levels were lower in the males (P < 0.01) than in the females and serum testosterone/SHBG ratio in M70 and in F70 were lower (P < 0.05) than in M50 and in F50, respectively. In the females significant positive correlations were observed between the individual values in serum testosterone concentration and the values both in the CSA (r= 0.46; P < 0.05) and in maximal force (r= 0.62; P < 0.01) as well as between serum testosterone/SHBG ratio and both the CSA (r= 0.55; P < 0.05) and maximal force (r= 0.68; P < 0.01). The present results imply that the decreasing basal level of blood testosterone over the years in aging people, especially in females, may lead to decreasing anabolic effects on muscles thus having an association with age-related declines in the maximal voluntary neuromuscular performance capacity in aging people.     

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。