Changes in the ultrastructure of striated muscles and neuromuscular synapses of rats under the effects of a 13-day space flight

The ultrastructure of myofibers and neuromuscular synapses (NMS) of soleus, gastrocnemius and diaphragmatic muscles of rats flown on Cosmos biosatellite for 13 days was examined two days after landing. The myofibers showed atrophic and dystrophic changes that were different in various muscles: they were advanced in m. soleus, moderate in m. gastrocnemius and weak in the diaphragm. The greatest changes of NMS were seen in m. soleus, where the surface area of synaptic contacts decreased due to partial or total destruction of presynaptic structures. In m. gastrocnemius, structural changes in the synaptic apparatus included terminal sprouting. In the diaphragm, plastic changes of NMS were detected. It is stressed that electron microscopic changes in m. soleus reflect pathological shifts related to hemodynamic disorders that develop after landing.     

Roentgenological and pathomorphological changes in the canine heart during 6-months hypokinesia

The effect of 6-month hypokinesia on the cardiac function and pathomorphological changes in 8 dogs was investigated. The heart size during systolic and diastolic contractions, stroke volume and contractile function were measured once a month, using an X-ray unit and a kymograph. After the hypokinetic exposure 6 dogs were sacrificed and their hearts were examined morphologically and histochemically. The recovery processes were investigated on 2 other dogs that were allowed to survive for 30 days after exposure. The 6-month hypokinesia led to a significant decrease in the heart size, stroke volume, cardiac index, and the contractile function. Post-mortem morphological examinations revealed atrophic changes in the myocardium. Electron-microscopy investigations demonstrated focal destructive changes in myofibers and in mitochondria: some of them were denser while others had a more transparent matrix and degraded crystae. Histochemical data (increased acid and alkaline phosphatase) also suggested atrophic and destructive changes in the myocardium. The above changes did not return to normal within 30 days of the recovery period.     

Skeletal musculature of rats during modeling of the physiological effects of weightlessness (morphological study)

In the experiment rats were suspended in the head-down position (at -15 to -20 degrees) for 21 days. To study the effect of this exposure on skeletal muscles of their fore- and hindlimbs, morphological and histochemical methods were used. Changes in the hindlimbs were similar to those seen in real weightlessness of similar duration. The two antigravitational muscles - soleus and gastrocnemius muscles - showed greatest changes, i.e. atrophic and metabolic shifts. The biceps brachii muscle that changes insignificantly in the weightless state developed a destructive process (with degradation of myofibers) that was later replaced with a reparative process. The changes in this muscle are assumed to be associated with hemodynamic disorders. It is recognized that the method of rat suspension is adequate for a ground-based study of morphological effects of weightlessness on hindlimbs and is unacceptable for that of forelimbs where the exposure induces microcirculation disorders.     

Dynamics of rat's soleus muscle recovery from the suspension-induced atrophy]

Dynamics of the 60-d soleus recovery was studied morphologically and histomorphometrically in female rats exposed to 30-d tail-suspension. Suspension led to soleus atrophy manifested by substantial losses in mass (56% vs. the control) and cross-sectional area of myofibers, and partial transformation of slow fibers into fast. The most intensive recovery processes in the soleus, reverse to the atrophic ones, were observed in the period between days 2 and 8 of readaptation, but then they subsided. Full recovery of the soleus mass and CSA took approximately 60 days of readaptation. Fast myofibers are less susceptible to atrophy and, therefore, recovered sooner than the slow ones. Percentage of slow-to-fast fibers returned to the norm between days 14 and 30. In addition to the persisting atrophy on readaptation day 2, there were some hemodynamic disorders in the soleus fraught with interstitial edema, distortion of muscle trophism, dystrophic developments in muscle fibers, and death of a number of fibers. Edema faded away between days 8 and 14 of readaptation. Recovery of the soleus muscle was considerably compromised by hemodynamic disorders at the beginning of readaptation.     

State of skeletal muscle fibers in rats during physical exercise after anti-orthostatic tail suspension in modeling the weightlessness

The state of myofibers of types I, IIA and IIB of biceps femoris m. of Wistar rats exposed to tail suspension for 14 or 21 days was investigated after they experienced a 15-minute locomotor load: running on a treadmill or hindlimb stretching. In all types of myofibers both exposures prevented the development of most structural and metabolic changes that occurred in response to suspension simulating the physiological effects of weightlessness. The distribution and level of variations of muscle parameters depended on the kind of exposure and type of myofibers.     

健脾益气冲剂对不同病理分级慢性萎缩性胃炎患者HSP70表达影响的比较

 目的通过健脾益气冲剂对不同病理分级慢性萎缩性胃炎(Chronic atrophic gastritis,CAG)患者热休克蛋白70(HSP70)表达影响差异的比较,以探讨该方的作用机制.方法观察病理变化,并以酶联免疫技术对患者治疗前后胃黏膜匀浆HSP70进行检测.结果治疗前,轻、中度组慢性萎缩性胃炎患者HSP70含量与对照组比较明显增高(P＜0.05),重度者无明显差异(P＞0.05);治疗后与治疗前比较,轻、中度组HSP70含量显著增高(P＜0.01),重度组明显增高(P＜0.05).轻、中度者疗效明显高于重度者(P＜0.05).结论轻、中度与重度慢性萎缩性胃炎患者存在HSP70表达的差异,这种差异对萎缩性胃炎患者的疗效有一定影响;健脾益气冲剂对萎缩性胃炎的疗效与促进HSP70表达有关.     

Examination of skeletal muscles of rats after a short-term flight on Cosmos-1667

Using morphological and histochemical methods, skeletal muscles (soleus, gastrocnemius), quadriceps and biceps muscles) of Wistar-SPF rats flown for 7 days on Cosmos-1667 were investigated. The short-term exposure to microgravity led to muscle atrophy which primarily involved myofibers with a high level of oxidative metabolism and a low level of ATPase activity. The percentage composition of myofibers of different types remained unchanged. The soleus muscle showed the greatest changes which included both atrophic and dystrophic shifts. Muscle atrophy developed together with metabolic changes that resulted in glycogen accumulation and decreased SDH activity. After return to Earth's gravity microcirculation disorders were seen only in the soleus muscle.     

Impact of repetition number on muscle performance and histological response

Skeletal muscle injury is major concern in sport- and occupation-related fields. PURPOSE: We investigated the effects of increasing stretch-shortening contraction (SSC) repetition number in vivo and the resulting changes in functional performance and quantitative morphometry in rat skeletal muscle. METHODS: Functional testing was performed on the ankle dorsiflexor muscles of Sprague-Dawley rats, which were randomly exposed to 30 SSC, 70 SSC, 150 SSC, or 15 isometric contractions of equal duration. Changes in functional performance and muscle morphometry were assessed at 48 h after exposure. Stereology was used to quantify the volume density of degenerative myofibers and normal myofibers in the tibialis anterior muscle from each group, as well as measures of inflammation and swelling and changes in the interstitial space. RESULTS: At 48 h there was a significant decline in isometric force for the 70- and 150-SSC groups (P < 0.05 and P < 0.05, respectively). Stereological measures indicated significant decreases in the percentage of volume density of normal myofibers in the 70- and 150-SSC groups (P < 0.05). Measures for percentage of volume density of degenerative myofibers and inflammation were increased (P < 0.0001 and P < 0.05, respectively) in the 70- and 150-SSC groups. Moreover, a significant increase in the percentage of volume density of degenerative myofibers in the 150-SSC group compared with the 70-SSC group was observed (P < 0.05). CONCLUSION: These data strongly suggest that exposure to increasing SSC repetitions results in increased functional decrements and morphometric indices of myofiber degeneration and inflammation, and that there is an apparent threshold (repetition number) at which this occurs.     

MEBO治疗萎缩性鼻炎20例报告

目的：探讨湿润烧伤膏治疗萎缩性鼻炎的疗效。方法：对２０例萎缩性鼻炎患者采用湿润烧伤膏治疗。结果：有效率１００％、优于以往传统的药物治疗方法。结论：湿润烧伤膏治疗萎缩性鼻炎起效快，使用方便，无任何毒副作用。     

大鼠臂丛神经损伤后萎缩骨骼肌基因表达谱的变化

目的：研究大鼠臂丛神经损伤后骨骼肌萎缩肌肉中基因表达谱的变化，探寻与去神经肌萎缩有密切关系的基因。方法：应用臂丛神经损伤后骨骼肌萎缩的大鼠模型（鼠数＝6），右侧上肢萎缩肌肉为实验组，左侧正常肌肉为对照组。荧光逆转录标记mRNA，采用鼠基因表达谱芯片检测正常肌肉与萎缩肌肉基因表达谱，并对比分析检测结果。结果；臂丛神经损伤后萎缩骨骼肌基因表达有差异的共148组，其中17组上调，131组下调。结论：在臂丛神经损伤的萎缩的骨骼肌中，与细胞凋亡相关基因的表达发生改变，促使细胞凋亡。一些与线粒体相关的基因表达的改变提示萎缩肌肉中线粒体的功能发生异常，糖、蛋白质和脂肪代谢关键酶基因表达的下调导致肌细胞内能量代谢严重障碍。     

替普瑞酮与传统铋剂治疗萎缩性胃炎疗效的对比观察

目的 比较替普瑞酮与传统铋剂治疗萎缩性胃炎临床的疗效.方法将205例萎缩性胃炎患者随机分为替普瑞酮治疗组(101例)、传统铋剂治疗组(104例),观察两组治疗前后主要症状、胃镜检查及胃黏膜组织病理学改变.结果从症状缓解、胃镜下黏膜改变及胃黏膜组织学变化各方面显示,替普瑞酮治疗组疗效均明显优于传统铋剂治疗组(P均＜0....     

Characterization of muscles injured by forced lengthening. II. Proteoglycans

After forced muscle lengthening of rat soleus muscle, alterations in muscle connective tissues were monitored by fluorescent immunohistochemical methods. Monoclonal antibodies directed against the polysaccharide attachment region of proteoglycans were used to observe changes in localization of 4-sulfated, 6-sulfated, or unsulfated chondroitin sulfate disaccharide units covalently bound to the proteoglycan protein core after injury. Additionally, fluorescein-labeled concanavalin A lectin and polyclonal antiserum to heparan sulfate proteoglycan were also localized in muscle sections during the regenerative process over 5 days after injury. Although proteoglycan localization was absent at or near the site of myofiber damage after injury, some distinct basal lamina remained as a matrix for regenerating myofibers. By the fifth day post-injury, the localization of these matrix components had returned to that seen in uninjured soleus muscles. The physiological significance of these extracellular matrix changes appeared to center on the repair of the torn myofiber and indicate an interdependence between myofibers and the extracellular matrix in this type of regeneration.     

Pituitary atrophy in Korean (epidemic) hemorrhagic fever: CT correlation with pituitary function and visual field

Eleven patients with Korean (epidemic) hemorrhagic fever were each studied three times with high-resolution CT in order to demonstrate necrosis of the pituitary gland and to correlate the CT findings with the patients' pituitary function and visual fields. Seven of the 11 patients showed varying degrees of progressive decrease in the height of the pituitary gland: one severe, two moderate, and four mild. The visual fields of all the patients were checked at the time of the third (last) follow-up CT. Six of the 11 patients had bitemporal superior quadrantanopsia. In five patients, the decreased height (atrophic change) of the pituitary gland and the visual-field defect were coincidental. The visual-field defects in those patients were not improved on follow-up examination 5 weeks later. Two patients in whom a 1-year follow-up examination was performed showed no interval changes in the defects. Pituitary function tests were performed in nine of the 11 patients (six with atrophic pituitary glands and three without atrophic changes) at the time of the third CT. Five of the six patients with atrophy showed decreased pituitary reserve function for follicle-stimulating hormone, cortisol, or human growth hormone, while only one patient showed decreased reserve function for cortisol among the three patients without atrophic change. The pituitary atrophic changes observed on follow-up sellar CT are thought to be the result of the ischemic necrosis of the gland. The high probability (five of seven) of visual-field defects in those patients with atrophic glands suggests optochiasmatic and pituitary ischemia as the basic pathogenesis.     

Healing of skeletal muscle injury: an ultrastructural and immunohistochemical study

The healing of gastrocnemius muscle injury induced with a spring-loaded hammer in rats was analysed ultrastructurally and immunohistochemically. The ends of the ruptured myofibers retracted, which resulted in a central blood filled cavity. Central zone (CZ) later becomes occupied by granulation tissue scar. CZ is surrounded by a zone where myofibers are necrotized and phagocytosed by days 2-3. Complete regeneration within the preserved basal lamina (BL) cylinders takes place in 5-7 days. The regeneration of myofibers across the scar follows a pattern different from that within BL cylinders. Thin, often branched, myotubes grow out of the BL cylinders into the granulation tissue, where they extend between fibroblasts and collagen fibrils, in general oriented parallel to the preserved myofibers. The extension of the regenerating myotube seems to take place primarily by local synthesis in the growth cone. Fusing myoblasts provide nuclei, mostly along the sides but also occasionally at the tip of myotubes. Some myoblasts seem to derive from undifferentiated cells in the granulation tissue. By three weeks only a few thin myotubes had extended across the gap between the stumps of the ruptured myofibers. Growing myotubes appear to attach to the surrounding connective tissue by specialized structures, an attachment which evidently transmits contraction force across the gap, allowing use of the injured limb before the healing is complete.     

Effect of impact stresses on the rat heart and hemodynamics]

An experimental impact on the rat chest in the cardiac area induced bradycardia, arrhythmia, ectopic beats, atrio-ventricular blockade that was followed by a fall of the arterial pressure and a rise in the venous pressure, a decrease of the cardiac output and blood volume. Breakages in cardiac myofibers were seen under the microscope. These changes can be brought about by a direct effect of impact accelerations on the heart. It is concluded that tolerance of the animal heart to impact accelerations is limited by bradycardia, arterial pressure fall and a 25% decrease of the cardiac output. Greater effects may produce breakages in myofibers. An active alertness and unloading of the right atrium increase the heart tolerance to impact accelerations and potassium chloride prevents hazardous cardiac arrhythmias.     

Five-year retrospective changes in hippocampal atrophy and cognitive screening test performances in very mild Alzheimer's disease: the Tajiri Project

The medial temporal lobe, especially the hippocampus, is important for normal cognitive function. especially for memory, and is the region with the earliest and most extensive pathological changes in Alzheimer's disease (AD). We investigated the atrophic changes of the hippocampus over a 5-year period and its relation to cognitive screening test performances in normal elderly subjects, those with very mild AD, and patients with AD. Fifty-seven elderly subjects without a moderate or greater degree of cerebrovascular disease as shown by MRI were randomly selected from the town of Tajiri. Thirty-three subjects with a clinical dementia rating (CDR) of 0 (normal), 18 CDR-0.5 (very mild AD) subjects, and six CDR-1&2 (AD) subjects underwent MRI and the Mini Mental State Examination (MMSE) twice during the period. Retrospective changes in the hippocampal width and the MMSE scores were evaluated. There were significant CDR group effects for the changes in the mean bilateral hippocampal widths and the MMSE scores. Normal subjects did not show cognitive decline, although there was a slight tendency for hippocampal atrophy. A significant and meaningful Spearman's correlation was noted between left hippocampal atrophy and the MMSE scores over the 5-year period for the CDR-0.5 group. These CDR-0.5 subjects met the MCI (mild cognitive impairment) criteria as proposed by the consensus paper. Findings suggested that normal elderly subjects maintain a high level of cognitive functions for at least 5 years, although hippocampal atrophy might occur. Atrophic change of the left hippocampus might be a good marker of the very early stage of AD.     

Myofibers express IL-6 after eccentric exercise

BACKGROUND: Interleukin (IL)-6 is locally produced in skeletal muscles and shows a remarkable increase in plasma after eccentric exercises. OBJECTIVE: To elucidate the cell types in the muscles responsible for IL-6 production after eccentric exercises. STUDY DESIGN: Controlled laboratory study. METHODS: An eccentric contraction model was made using electrical stimulation. The authors investigated the muscle damage and regeneration processes after eccentric exercises histologically, and the cell types expressing IL-6 and its subcellular compartimentalization with time immunohistochemically after eccentric exercises. RESULTS: Swollen myofibers were detected from 8 hours to 3 days after exercises. Disrupted myofibers were detected from 24 hours to 7 days, with a peak of 3 days. IL-6 was detected only in the cytoplasm of myofibers until 12 hours; thereafter, it was found in the inflammatory cells and proliferating satellite cells as well. The swollen myofibers were negatively stained for IL-6. The positive ratios of IL-6 in myofibers immediately increased after exercises, peaked in 12 hours, and then decreased. CONCLUSIONS: After eccentric exercises, IL-6 expression increased in myofibers preceding the disruption of myofibers. IL-6 might be closely related to muscle damage caused by strenuous exercises.     

Relation between myofibers and connective tissue during muscle injury repair

The connective tissue framework in skeletal muscle combines the contractile myofibers into a functional unit, in which the contraction of myofibers is transformed into movement via myotendinous junctions (MTJs) at their ends, where myofibers attach to tendons/fascia. The cytoskeletal contractile myofilament apparatus adheres through subsarcolemmal and transmembrane molecules to the surrounding extracellular matrix, with integrin and dystrophin associated chains of molecules being the two main adhesion complexes. In shearing type of muscle injury both myofibers and the connective tissue framework are ruptured and thereby the functional tendon–muscle–tendon units are disrupted. The stumps of the ruptured myofibers are separated and at the same time joined by a connective tissue scar, through which the ends of regenerating myofibers try to pierce, but as the scar becomes more compact the ends attach to the scar by new mini-MTJs. During the early phase ruptured myofibers try to compensate for the lost MTJ attachment by reinforcing their integrin mediated lateral adhesion, which returns to normal low level after formation of the mini-MTJs and at which time complementary increase of dystrophin and associated molecules on lateral sarcolemma takes place. The stumps appear to remain separated by and attached to the interposed scar for many months, possibly for ever, i.e. the original tendon–muscle–tendon units may have become permanently divided into two consecutive units. Remarkably, axon sprouts are able to penetrate through the interposed scar to form new neuromuscular junctions on those abjunctional stumps which were denervated by the rupture.     

Effect of immersion hypokinesia on the parameters of human muscle potentials

During 3-day immersion hypokinesia stimulation muscle potentials and averaged potentials of total EMG of m. biceps brachii were investigated in six test subjects. Stimulation potentials were obtained by exciting n. cutaneous with a train of square impulses. Potentials were recorded using a combined multi + electrode. Averaged potentials of total EMG were recorded by means of the same electrode. The propagation rate of the potentials, duration of their negative and end-positive phases as well as the length of their negative phase in space were measured. In addition, vector-electromyographic images of the potentials were recorded. After immersion hypokinesia the propagation rate decreased significantly, the duration of the end-positive phase increased and the length of the depolarized zone of potentials in space shortened. The decrease of the rate of propagation of stimulation potentials was 28% and that of averaged potentials of total EMG was 31% per group. These changes developed rapidly enough, indicating shifts in the properties of potentials of action of myofibers during immersion. Factors responsible for these changes are discussed.     

Morphohistochemical study of skeletal muscles in rats after experimental flight on "Kosmos-1887"

Morphometric and histochemical methods were used to examine the soleus, gastrocnemius (medial portion), quadriceps femoris (central portion) and biceps brachii muscles of Wistar SPF rats two days after the 13-day flight on Cosmos-1887. It was found that significant atrophy developed only in the soleus muscle. The space flight did not change the percentage content of slow (type I) and fast (type II) fibers in fast twitch muscles. During two days at 1 g the slow soleus muscle developed substantial circulation disorders, which led to interstitial edema and necrotic changes. The gastrocnemius muscle showed small foci containing necrotic myofibers. Two days after recovery no glycogen aggregates were seen in myofibers, which were previously observed in other rats examined 4--8 hours after flight. An initial stage of muscle readaptation to 1 g occurred, when NAD.H2-dehydrogenase activity was decreased.