Switch movements and the myosin crossbridge stroke

The myosin II motor from Dictyostelium discoideum has been engineered to contain single tryptophan residues at strategic locations to probe movements of switch 1 and switch 2. The tryptophan residue at W501 probes movement of the relay helix and indirectly reports on switch 2 movement. This probe suggests that there is an equilibrium between the switch 2 open- and closed-states when the γ-phosphate position is occupied. Actin does not appear to greatly affect this equilibrium directly, but has indirect influence via switch 1. The latter region has been probed by introducing tryptophan residues at positions 239 and 242. The kinetics of the actomyosin ATPase in solution is discussed with respect to recent crossbridge models based on high-resolution crystal structures. To whom correspondence should be addressed: Tel.: +44-(0)-116-229-7048; Fax: +44-(0)-116-229-7018; E-mail: crb5@le.ac.uk     

Analysis of Evoked EEG Synchronization and Desynchronization During Perception of Emotiogenic Stimuli: Association with Autonomic Activation Processes

The cortical apparatus involved in performing autonomic responses in conditions of emotional activation has received little study. The aim of the present work was to assess the dynamics of evoked EEG synchronization and desynchronization at different frequency ranges during the perception of emotiogenic visual stimuli depending on the extent of accompanying autonomic activation as measured by skin galvanic responses. Studies were performed on 33 students (all right-handed) aged 18–28 years. Difference between subjects with weak (SGR^-) and strong (SGR⁺) skin galvanic responses were seen only in the θ1 range (4–6 Hz). At the stage at which emotiogenic information was perceived (the first second after the start of stimulus presentation), both groups showed similar dynamics of increases in evoked synchronization in the parietal-temporal-occipital areas of the cortex, with greater involvement of the right hemisphere. From the second second to the end of presentation (2–6 sec), emotiogenic signals gave significantly greater levels of evoked synchronization in these cortical areas as compared with neutral stimuli, and only in the SGR⁺ group. These data provide evidence for the involvement of the posterior areas of the cortex of the right hemisphere in the mechanisms of motivational attention and sympathetic activation. __________ Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 90, No. 11, pp. 1314–1323, November, 2004.     

Immune privilege induced by cotransplantation of islet and allogeneic testicular cells

Objective To induce islet allograft long- term survival through cotransplantation of islet cells with sertoli cells. Methods Testicular sertoli cells were prepared by digestion with collagenase, trypsin an d DNase, and were cultured for 48 hours. Collagenase digested and Ficoll purifi ed donor (Wistar rat) islets were cotransplanted with allogeneic sertoli cells i n the absence of systemic immunosuppression. Terminal deoxynucleotidyl transfer ase- mediated X- dUTP nick- end labeling (TUNEL) was used to label apoptosis of lymphocytes surrounding the islet graft. Results Cotransplantation of islets and 1×10(7) sertoli cells reversed the diabetic sta te for more than 60 days in 100% (6/6) of the chemically diabetic Sprague Dawley rats. Grafts consisting of islets alone or islets plus 1×10(5) sertoli cells survived only for 5-6 days. Apoptosis of lymphocytes surrounding the islets was quite clear. Conclusion Cotransplantation of islets with FasL［+］ sertoli cells induces local immune priv ilege and allows long- term graft survival without systemic immunosuppression.     

Prevalence of osteoporosis and incidence of hip fracture in women - secular trends over 30 years

Background  

The number of hip fractures during recent decades has been reported to be increasing, partly because of an increasing proportion of elderly women in the society. However, whether changes in hip fracture annual incidence in women are attributable to secular changes in the prevalence of osteoporosis is unclear.     

Neurophysiological Correlates of Induced Discrete Emotions in Humans: An Individually Oriented Analysis

Studies on 30 right-handed subjects addressed EEG characteristics (62 channels) in conditions of laboratory simulation of induced emotions of happiness, joy, anger, disgust, fear/anxiety, and sadness. Induced emotions were found to produce, along with common features, individual patterns in the distribution of amplitude-frequency EEG characteristics. Induced positive and negative discrete emotions were characterized by interhemisphere activatory asymmetry in the theta-2 (4–6 Hz), alpha-2 (10–12 Hz), and beta-1 (12–18 Hz) ranges. Experience of the emotions of joy, anger, and disgust occurred on the background of asymmetrical increases in activity in the anterior cortex of the left hemisphere in the theta-2 range, suggesting a leading role for the activity of these areas in realizing the cognitive components of emotional reacting. In addition, some high-ergicity negative emotions evoked combined alpha-2 and beta-1 desynchronization (disgust) or beta-1 desynchronization (fear/anxiety) in the right parietal-temporal cortex, suggesting its involvement in the mechanisms of non-specific emotional activation. These data provide evidence that each of these emotions is characterized by its own individual pattern in the distribution of the amplitude-frequency characteristics of the EEG and, on the other hand, that series of ranges and cortical areas show similar but different (in terms of intensity) effects in response to emotional activation for emotions of different flavor. __________ Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 90, No. 12, pp. 1457–1471, December, 2004.     

Anthropometric and Dietary Evaluations in a Sample of “Healthy” Mexican Older Adults

The purpose of this study was to describe anthropometric, metabolic, and nutritional characteristics in healthy elderly adults in a primary health care setting. It was conducted through a cross-sectional study of 80 subjects 60 years of age and older. After confirming healthy status, clinical, biochemical, dietetic, and anthropometric evaluations were performed. The findings indicated 22% had anemia, 22% had impaired glucose tolerance, 46% had hypertriglyceridemia, and 51% had hypercholesterolemia. More than 50% had obesity, and almost 80% had a high risk waist circumference measure. Mean energy intake was normal; however, more than 50% of participants did not have adequate intakes of potassium, calcium, magnesium, zinc, folic acid, and vitamins B₁₂ and A. Inadequate food intakes were common. Specific examples are that 16% of the subjects ate no meat/egg, 31% ate no dairy products, 56% ate no legumes, 22% ate no fruits, and 41% ate no vegetables. Additionally, 31% consumed soft drinks. Therefore, we can conclude that elderly people otherwise considered as “healthy” nonetheless had a high proportion of obesity and cardiovascular risk factors. Inadequate dietary patterns were also observed and corresponded with poor micronutrient intake.     

2型糖尿病患者强化降糖治疗的效果和预测指标

为观察2型糖尿病患者强化降糖治疗的预测指标,强化降糖对糖化血红蛋白（HbA1c）、体重、焦虑／抑郁症状、健康状况的影响,以及强化降糖使HbA1c得到改善的患者的特点,研究者收集来自TRIAD（Translating Research into Action for Diabetes）的数据并分析,对起初采用饮食、运动、口服降糖药治疗、HbA1c〉7．2％、持续治疗或强化治疗（开始或增加口服降糖药种类或开始胰岛素治疗）超过18个月的患者进行检查。     

葛根素对小鼠实验性微循环障碍的改善作用

本文报告了葛根素对肾上腺素(Adr)引起的小鼠肠系膜微循环障碍的影响,并与罂粟碱作比较。结果表明,预先局部滴注0.5%葛根素能够拮抗Adr所致微动脉收缩、流速减慢和流量减少;而局部先滴注Adr造成微循环障碍后,再局部滴注1%葛根素,获得与上类似结果。给小鼠ⅳ葛根素(52 mg/kg)后再局部滴注Adr,可减轻Adr引起的微动脉收缩、流速减慢和流量减少,其作用优于罂粟碱。因此葛根素可改善实验性微循环障碍。     

Hemoglobin Nigeria (alpha-81 Ser replaced by Cys):a new variant associated with alpha-thalassemia

Hematologic evaluation of a Nigerian obstetrical patient disclosed the presence of sickle-cell trait as well as evidence of a hemoglobin alpha- chain abnormality. Hemoglobins containing the variant alpha-chain were isolated by DEAE-cellulose column chromatography, and analysis of the purified alpha-chain demonstrated a ser replaced by cys substitution at alpha-81. The abnormal alpha-chain represented approximately 45% of the total, and hemoglobins containing this alpha-chain appeared to have normal stability and functional properties. In addition to the abnormal hemoglobins that were identified in this patient, she also was found to have persistent microcytosis in the absence of iron deficiency, and the percentage of HbS in her erythrocytes was less than that usually present in individuals with sickle cell trait. These findings, together with a reduced alpha/beta globin synthesis ratio from her peripheral blood reticulocytes, indicated that the presence of alpha-thalassemia trait. Hematologic findings from members of the patients's family suggest that an alpha-thalassemia gene may be linked to that of the structurally abnormal alpha-chain.