Load changes in limbs during orienting in non-restrained cats

We simultaneously investigated eye and head movements and postural adjustment during orienting by measuring load force exerted by four limbs in cats. When light is moved from the fixation point to the target position, the head first begins moving towards the target position, and the eye moves in the opposite direction due to the vestibulo-ocular reflex (VOR). Later, the eye moves quickly in the target direction by saccade, synchronous with the remaining rapid head orientation movement. Head movement is classified as either 'head rotation' or 'head translation'. During head rotation, the load force in ipsilateral limb to the target position decreased, and that in the contralateral limb increased. During head translation, on the contrary, load force in the ipsilateral limb increased and that in the contralateral limb decreased. This phenomenon was observed in fore- and hindlimbs. The latencies of head movement are very similar with those of the load force change in many trials, and in case in which the head movement has short latency, the amount of load force change is larger. In contrast, when head movement has long latency, the amount of load force change is smaller. In a previous study, we recorded two types of neurons from ponto-medullary reticular formation. The firing of these neurons was related with head movement. The cervical reticulospinal neuron (C-RSN) in ponto-medullary reticular formation got off collateral to both neck and forelimb motoneurons. These types were named phasic neuron (PN) and phasic sustained neuron (PSN). We discuss the relation between load changes and the two types of neurons and postural adjustment during orienting.     

Head and pelvic vertical displacement in dogs with induced swinging limb lameness: an experimental study

Background

Swinging limb lameness is defined as a motion disturbance ascribed to a limb in swing phase. Little is known about its biomechanics in dogs, particularly about the body motions that accompany it, such as vertical head and pelvic motion asymmetry. The aim of this study was to describe the changes in vertical head and pelvic motion asymmetry in dogs with induced swinging limb motion disturbance, mimicking a swinging limb lameness. Fore- and hind-limb lameness was induced in ten sound dogs by placing a weight (200 g) proximal to the carpus or tarsus, respectively. Marker-based motion capture by eight infrared light emitting video cameras recorded the dogs when trotting on a treadmill. Body symmetry parameters were calculated, including differences between the two highest positions of the head (HDmax) and pelvis (PDmax) and between the two lowest positions of the head (HDmin) and pelvis (PDmin), with a value of zero indicating perfect symmetry.

Results

Induction of swinging forelimb lameness showed significant changes in HDmax (median and range: sound 1.3 mm [??4.7 to 3.1], in the left side ??28.5 mm [??61.2 to ??17.9] and in the right side 20.1 mm [??4.4 to 47.5]) and, induction of swinging hind limb lameness showed significant changes in PDmax (sound 2.7 mm [??7.4 to 7.2], in the left side ??10.9 mm [??22.4 to 0.5] and in the right side 8.6 mm [??3 to 30]), as well as an increased hip movement asymmetry (sound 1.6 mm [??8.6 to 19.9], in the left side ??18.1 mm [??36.7 to 5.4] and in the right side 15 mm [??20.7 to 32.1]) (P?<?0.05).

Conclusions

Induced swinging fore- and hind limb lameness resulted in significant increased asymmetry of the maximal vertical displacement movement of the head and pelvis, due to decreased lifting of the head in forelimb lameness and of the pelvis in hind limb lameness. The results suggest that asymmetry of the maximal vertical displacement of the head and pelvis (i.e. lifting) is a key lameness sign to evaluate during examination of swinging limb lameness.

     

Adaptive changes in running kinematics as a function of head stability demands and their effect on shock transmission

This study aimed to identify adaptive changes in running kinematics and impact shock transmission as a function of head stability requirements. Fifteen strides from twelve recreational runners were collected during preferred speed treadmill running. Head stability demands were manipulated through real-time visual feedback that required head-gaze orientation to maintain within boxes of different sizes, ranging from 21° to 3° of visual angle with 3° decrements. The main outcome measures were tibial and head peak accelerations in the time and frequency domains (impact and active phases), shock transmission from tibia to head, stride parameters, and sagittal plane joint kinematics. Increasing head stability requirements resulted in decreases in the amplitude and integrated power of head acceleration during the active phase of stance. During the impact portion of stance tibial and head acceleration and shock transmission remained similar across visual conditions. In response to increased head stability requirements, participants increased stride frequency approximately 8% above preferred, as well as hip flexion angle at impact; stance time and knee and ankle joint angles at impact did not change. Changes in lower limb joint configurations (smaller hip extension and ankle plantar-flexion and greater knee flexion) occurred at toe-off and likely contributed to reducing the vertical displacement of the center of mass with increased head stability demands. These adaptive changes in the lower limb enabled runners to increase the time that voluntary control is allowed without embedding additional impact loadings, and therefore active control of the head orientation was facilitated in response to different visual task constraints.     

Role of the motor cortex in the control of axial and proximal muscles in learning

Involvement of the motor cortex in the control of the shoulder and the scapula muscles was studied during acquisition of the novel head-forelimb coordination in dogs. The dogs were trained to raise the forelimb fixed to the lever in order to lift a food-containing cup and keep it elevated during eating with the head tilted down to the feeder. At the early stage of learning, the movement of raising the limb occurred with an anticipatory upward head tilt, whereas the head tilt to the feeder was associated with the lowering of the raised limb. Food consumption required a new coordination, i.e., maintaining the raised limb in a posture with the head lowered. This coordination could only be achieved by learning. This new coordination was critically dependent on the intact motor cortex. It was found that in the natural coordination, raise of the limb involved regular activation of the main flexors of shoulder, i.e., deltoid and teres major muscles, and inconstant participation of teres minor, supra- and infraspinatus, trapezius muscles. Muscles of the latter group were often active during standing but ceased their activity before limb raise. The learned limb raise with the head tilted down occurred with activation of all the mentioned muscles, and some of them changed their activity for the opposite pattern. Lesions in the motor cortex (inclusive the main part of the projection area of the "working" limb) led to a restoration of the natural head-fore- limb coordination and the innate muscle pattern of the limb raise. Thus, in the course of learning, the motor cortex rearranges the innate pattern of coordination of phylogenetically old axial and proximal muscles, which begin to work in a new manner.     

Endothelin induces vascular and mucosal lesions, enhances the injury by HCl/ethanol, and the antibody exerts gastroprotection.

Vascular factors play an important role in the pathogenesis and prevention of acute gastric mucosal lesions. Endothelin-3 (ET-3), a potent vasoactive peptide, was infused intra-arterially to induce gastric microvascular and hemorrhagic mucosal lesions, and to enhance the damaging effects of dilute HCl and ethanol. ET-3 antibody was injected intravenously to decrease hemorrhagic mucosal lesions induced by ethanol. Locally infused ET (0.01, 0.1, and 1.0 nmol.100 g-1.min-1 for up to 15 min) was followed in some cases by intragastric dilute ethanol or HCl, which alone caused no or only mild vascular and mucosal lesions. Monastral blue was used to visualize and quantify vascular injury. ET-3 produced dose-dependent vascular lesions that affected the walls of mucosal capillaries and venules and induced mucosal congestion and focal endothelial labeling in vessels of the gastric muscular layers. The highest dose of ET induced hemorrhagic gastric mucosal lesions, mortality, and periods of hyper- and hypotension in the rat. Medium and low doses of ET-3 caused vascular injury, and dose-dependently potentiated the vascular and hemorrhagic mucosal lesions caused by dilute HCl and ethanol. Indomethacin slightly enhanced damage induced by ET and 50% ethanol, suggesting a limited mediatory role of prostaglandins in the ET-induced mucosal lesions. Anti-ET-3 serum dose-dependently decreased but did not abolish the hemorrhagic gastric mucosal lesions induced by 75% ethanol. Thus, ET-3 causes endothelial damage in capillaries and venules of rat stomach and predisposes to mucosal damage even after exposure to dilute ethanol or HCl. ET is more potent than leukotrienes and histamine and thus may play an important role in the mechanisms of acute gastric mucosal injury and protection where the vascular network appears to be a major target.     

De novo expression of the hemoglobin scavenger receptor CD163 by activated microglia is not associated with hemorrhages in human brain lesions

The main function of CD163 (hemoglobin scavenger receptor) is to bind the hemoglobin-haptoglobin complex, thereby mediating extravasal hemolysis. However, CD163 also has an antiinflammatory function. After CD163-mediated endocytosis, hemoglobin is catabolized further by hemeoxygenase 1 (HO-1). Previously, we found expression of HO-1 to be restricted to microglia/macrophages at sites of hemorrhages in human traumatic and ischemic brain lesions. We now investigated if CD163 expression is also correlated with hemorrhages in brain lesions. Methods. Autopsy brain tissue from 44 cases with hemorrhagic brain lesions (32 traumatic brain injuries/TBI, 12 intracerebral bleedings/ICB), 56 non-hemorrhagic brain lesions (30 ischemias, 26 hypoxias) and 6 control brains were investigated. The post injury survival times ranged from a few minutes to 60 months. Results. In controls, single perivascular monocytes expressed CD163, but only single CD163+ microglia were found in 3/6 cases. CD163+ cells in the parenchyma (activated microglia/macrophages) increased significantly within 24 hours after trauma and ischemia and within 1-7 days following ICB or hypoxia. Overall, significantly lower and higher levels of parenchymal CD163+ cells occurred in hypoxia and ischemia, respectively. Perivascular CD163+ cells also increased significantly in all pathological conditions. In areas remote from circumscribed brain lesions (TBI, ICB, ischemia), significant changes were only found in ICB and ischemia. Conclusions. De novo expression of CD163 by activated microglia/macrophages and CD163+ infiltrating monocytes are neither restricted to nor predominant in hemorrhagic brain lesions. Thus, the antiinflammatory function of CD163 probably predominates, both in hemorrhagic and non-hemorrhagic brain lesions and points to possible immunomodulatory treatment strategies targeting CD163.     

Role of oxygen-derived free radicals in hemorrhagic shock-induced gastric lesions of rats

This study was designed to determine whether oxygen-derived free radicals play a role in the pathogenesis of gastric lesions produced by hemorrhagic shock in the rat. Allopurinol (Zyloric), an inhibitor of xanthine oxidase (responsible for the formation of superoxide radicals) and MTDQ-DA (Kontrad), a synthetic antioxidant of dihydroquinoline type were used. In the anesthetized rat 0.1 N HCl was instilled into the stomach and the rat was bled to reduce the blood pressure to 30 mmHg for 20 min. The blood shed was retransfused. Twenty min later the stomach was removed. The area of gastric mucosal lesions were measured, the activity of endogenous peroxidase was examined histochemically and a histological grading was made. Both allopurinol and MTDQ-DA significantly protected against hemorrhagic shock-induced gastric lesions and peroxidation. These results suggest that oxygen-derived free radicals play an important role in the formation of gastric lesions produced by ischemia plus 0.1 N HCl.     

Postural adjustments to head movements in the cat

Head movements induced by motor cortex stimulation in the cat are accompanied by variations in the vertical force exerted by each limb. These postural responses were found to show stereotyped patterns: with head dorsiflexions an increase was observed in the force exerted by the anterior limbs and a decrease at the posterior limb level. From comparison between the latencies of the force variations, the beginning of head acceleration, and EMG activity in the limb extensor muscles, it was concluded that triggering of these postural responses is not reflex, but depends on the same command as the movement itself. This early response might be a means of avoiding the downward movement of the trunk which would otherwise result from the reaction force corresponding to the upward head movement.     

Effect of the moderate exercise on performance in upper/lower limb during long term bed rest

The purpose of this study was to investigate that considers the influence of the moderate exercise has on the upper limbs and the legs during 21 days head down bed rest. Therefore motor evoked potential (MEP) induced by transcranial magnetic stimulation (TMS) in lower leg muscles of four healthy subjects were investigated before/after and during bed rest. There were no significant differences statistically between soleus MEPs before and after bed rest in all subjects. However there were decreased tendancy in MEPs during non-exercise group. And then there were not change discriminal ability on differential threshold of weight sensory in scale test in all subjects during head down bed rest. Theses results indicate that the assign cognitive performance, sensory in scale for upper limb no changes during and after head down bed rest.     

Spatio-temporal gait characteristics during transitions from trot to canter in horses

Gaits can be defined based upon specific interlimb coordination patterns characteristic of a limited range of speeds, with one or more defining variables changing discontinuously at a transition. With changing speed, horses perform a repertoire of gaits (walk, trot, canter and gallop), with transitions between them. Knowledge of the series of kinematic events necessary to realize a gait is essential for understanding the proximate mechanisms as well as the control underlying gait transitions. We studied the kinematics of the actual transition from trot to canter in miniature horses. The kinematics were characterized at three different levels: the whole-body level, the spatio-temporal level of the foot falls and the level of basic limb kinematics. This concept represents a hierarchy: the horse's center of mass (COM) moves forward by means of the coordinated action of the limbs and changes in the latter are the result of alterations in the basic limb kinematics. Early and short placement of the fore limb was observed before the dissociation of the footfalls of one of the diagonal limb pairs when entering the canter. Dissociation coincided with increased amplitude and wavelength of the oscillations of the trunk in the sagittal plane. The increased amplitude cannot be explained solely by the passive effects of acceleration or by neck and head movements which are inconsistent with the timing of the transition. We propose that the transition is initiated by the fore limb followed by subsequent changes in the hind limbs in a series of kinematic events that take about 2.5 strides to complete.     

Natural coordination of the head and limb movements and its transformation by learning in dogs

Kinematic analysis of the head and the forelimb movements in dogs has been done during elaboration the instrumental tonic forelimb flexion when the head was bent down to foodwell. It was found, that in naive dogs the forelimb flexion was accompanied by anticipatory lifting of the head, the head lowering evoked extension of the flexed forelimb. Therefore simultaneous holding of the lifted limb and the lowered head was impossible and could be achieved only by learning. Studying of the dynamics of transformation of the innate (natural) head-forelimb coordination during learning has shown that innate relationship between phasic head-forelimb movements, which was lost at the early stage could spontaneously restore for a short time in trained dogs. It was found between low-amplitude head-forelimb oscillations which did not disturb the learnt tonic forelimb flexion, when the head was bent down. The innate coordination is supposed to be an inborn and in the given conditions the only possible way of the forelimb lifting, in which the anticipatory lifting of the head might facilitate the limb flexion. That's why lowering of the head provoked extension of the flexed limb. Contrary to the known hypothesis [4] that the mechanism of elaboration of the novel coordination is connected with suppression of the interfering innate coordination, it is proposed to consider the elaborated coordination as the novel way of the forelimb lifting in the forced posture of the lowered head. The novel flexion of the forelimb, as supposed, became possible by changing its innate organization (muscular pattern).     

cAMP在急性胃粘膜损害中作用的研究

本研究应用ＲＩＡ法,观察了大鼠胃组织ｃＡＭＰ含量与急性胃粘膜损害之间的关系。结果表明：（１）由消炎痛或失血性休克引起的急性胃粘膜损害时,胃组织ｃＡＭＰ含量明显降低;事先使用异搏定（１０ｍｇ／ｋｇ）可使胃组织ｃＡＭＰ含量明显增加,并使由消炎痛引起的急性胃粘膜损害相应减轻。（２）在正常情况下,胃窦、胃体组织间ｃＡＭＰ含量并非相等,胃窦部组织ｃＡＭＰ含量高于胃体部组织,与此相应的是急性胃粘膜损害主要局限在胃体部。上述引起急性胃粘膜损害的诸因素均可使这种差别加大。５和１０ｍｇ／ｋｇ剂量的异搏定可使消炎痛所致急性胃粘膜损害的大鼠胃体部组织的ｃＡＭＰ含量明显增加,与胃窦部组织ｃＡＭＰ含量的差值变小,结果是胃体部粘膜的损害明显减轻。提示胃组织ｃＡＭＰ含量变化在急性胃粘膜损害中有一定的作用。     

Tumor size-dependent elevations of serum gangliosides in patients with head and neck carcinomas

Serum gangliosides were studied in 100 patients with benign or tumoral head and neck lesions. Whereas very few changes over the normal level were noticed in benign cases, 78% of patients with head and neck carcinomas had a significant elevation of serum gangliosides, mostly accounted for by GM3 and GD3. Such an increase was correlated with the observed tumor size, and the level of serum gangliosides returned to normal within one month after surgery. Follow-up of patients showed that further elevations of serum gangliosides were associated with relapses.     

Isotope limb blood flow measurement in patients undergoing peripheral laser angioplasty

A technique of isotope limb blood flow (ILBF) measurement employing Technetium-labelled human albumin and a gamma camera, was used to assess limb perfusion in 19 patients undergoing percutaneous laser angioplasty, both before and one month after treatment. Twenty-three limbs with femoro-poplited occlusions ranging in length from 3–35 cm (median 8cm) were recanalized using an Nd-YAG laser and sapphire tipped optical fibre. Primary angiographic success was achieved in 19 lesions of which 6 re-occluded within the first month, and 13 remained patent with relief of symptoms. Clinically successful procedures were associated with a large increase in ILBF. However, normal blood flow was restored in only 54% of limbs. There was a slight decrease in limb perfusion after failed laser angioplasty but this was not statistically significant in this small series. Furthermore, there was no clinically apparent circulatory compromise, or need for urgent surgical bypass in failed cases. We conclude that ILBF is a useful means of assessing patients undergoing laser angioplasty, particularly for detecting small flow changes in patients who are unable to complete a standard exercise test. Its use can be recommended for assessing blood flow changes following other forms of limb revascularization.     

Effect of ellagic acid on gastric damage induced in ischemic rat stomachs following ammonia or reperfusion

We examined the effect of ellagic acid (EA), one of the polyphenols that are abundantly contained in whisky as a nonalcoholic component, on gastric lesions induced by ammonia plus ischemia or ischemia/reperfusion in rats, in relation to the antioxidative system. Under urethane anesthesia, a rat stomach was mounted in an ex vivo chamber, and the following two experiments were performed; 1) a stomach was made ischemic (1.5 ml/100 g body weight) for 20 min, followed by reperfusion for 15 min in the presence of 100 mM HCl; 2) a stomach was made ischemic by bleeding from the carotid artery (1 ml/100 g body weight), followed by intragastric application of ammonia (NH4OH: 120 mM). EA (0.1-10 mg/ml) was applied in the chamber 30 min before the onset of ischemia. Gastric potential difference (PD) and mucosal blood flow (GMBF) were measured before, during and after 20 min of ischemia. Ischemia/reperfusion caused a profound drop in GMBF followed by a return, and resulted in hemorrhagic lesions in the stomach in the presence of 100 mM HCI. These lesions were dose-dependently prevented by EA with suppression of lipid peroxidation but no effect on GMBF, and the effect at 6 mg/ml was almost equivalent to that of superoxide dismutase (SOD: 15000 unit/kg/hr) infused i.v. during a test-period. On the other hand, application of NH4OH to the ischemic stomach produced a marked reduction in PD, resulting in severe hemorrhagic lesions. These changes were prevented with both EA and SOD. In addition, EA had a potent scavenging action against monochloramine in vitro. These results suggest that EA exhibits gastric protective action against gastric lesions induced by NH4OH or reperfusion in the ischemic stomach, probably due to its anti-oxidative activity. This property of EA partly explains the less damaging effect of whisky in the stomach and may be useful as the prophylactic for Helicobacter pylori-associated gastritis.     

大鼠失血性休克后肠道微生态的改变

本研究对无特殊致病菌大鼠失血性休克后肠道微生态的改变及肠道细菌易位进行了动态观察。结果表明,失血性休克复苏后5小时,肠道微生态即发生改变,表现为回肠内肠杆菌菌量增多,肠道内类杆菌与肠杆菌菌量比值下降,而后这一改变随时间推移逐渐恢复;肠道细菌易位率也有类似变化,易位细菌以肠杆菌为主。结果提示,大鼠失血性休克后肠道细菌易位与肠道微生态的改变有密切关系。     

军都山古代人群股骨肌腱附着位点初步分析

肌肉通过肌腱、韧带附着于骨骼,附着位点的形态改变与肌肉功能相关,因而被用于古代人群肢体功能活跃度的复原。本文对东周时期军都山古代人群股骨的臀中肌、髂腰肌、腓肠肌内侧头三个纤维软骨性附着位点的形态进行了观测,并与清代君子村组进行对比,检验其形态变化与组别、性别、年龄、体型的相关性。结果表明,部分附着位点的形态改变随年龄而增加,但性别、体型及组别差异对附着位点形态变化的影响较小。这与很多上肢研究中发现的附着位点形态受性别、体型、劳动强度等影响结论不同。这种差别可能来自下肢承重以及更为复杂的功能状况等原因,军都山与君子村样本年龄结构的不一致性也是一个重要影响因素。对于古代人群下肢肌腱附着位点形态变化与其功能状况的关系需要更深入的探讨。     

Histopathological study of arthritic lesions induced by immunization with type II collagen in DBA/1J mouse

Eight male DBA/1J mice immunized twice by intradermal injection of type II collagen were autopsied 12 weeks after the first immunization and analyzed for anti-type II collagen antibody level, and the limb joints were examined radiologically and histopathologically. Clinical onset of swelling and erythema in the limb joints occurred about 5 weeks after the first immunization and deformity of the limbs was observed in a few animals about 5 weeks later. Although there were marked individual differences, serum anti-type II collagen antibody levels were elevated in all animals. Histopathologically, the changes were similar to those seen in human rheumatoid arthritis and were characterized by proliferation of synovial lining cells, formation of granulation tissue with destruction of cartilage and subchondral bone, and ankylosis. Systematic examination of various joints of the fore- and hind-limbs revealed definitely that the sequence of arthritic lesions was not uniform. The knee joint was involved most frequently, but smaller joints such as the phalangeal joints were involved less frequently but exhibited severe changes. The significance of histopathological examinations in the evaluation of effects of anti-rheumatic drugs was discussed with reference to this model.     

Are limb development and limb regeneration both initiated by an integumentary wounding?: A hypothesis

It is proposed that, whereas an actual wound to a salamander limb may initiate limb regeneration, a local and developmentally programmed integumentary wound may initiate limb development. The electrophysiological changes induced by these lesions of the skin may be a common denominator linking limb regeneration and limb development. Such early electrical events are considered to initiate or guide the early accumulation of cells, and to help to produce the local environment in which a limb will arise. This scheme provides a self-limiting positive-feedback mechanism for the production of a localized area where other developmental mechanisms act in concert with endogenous electrical fields (or in their complete absence), thereby leading to limb differentiation. This hypothesis may not be restricted to limb formation; it may be of more general significance, i.e. in the process of organogenesis in embryos. One might reasonably suggest that, by such a mechanism, any developing placode (for example, auditory or olfactory placodes) might form and localize.     

Cerebral toxoplasmosis with multiple hemorrhage lesions in an HIV infected patient: A case report and literature review

A 47-year-old man was admitted to a hospital for disturbance of consciousness. He was diagnosed with multiple hemorrhagic brain abscesses in bilateral hemispheres with human immunodeficiency virus (HIV) infection, and was transferred to our hospital for further examination and treatment. On admission, although he could respond to pain stimuli, he could not talk or communicate. His laboratory data on admission revealed CD4-positive T cell count of 67 cells/μL, and HIV1-RNA viral load of 5.6 × 10⁵ copies/mL. Both the serum IgG Toxoplasma gondii antibody and the cerebrospinal fluid polymerase chain reaction for Toxoplasma gondii DNA were positive. He was diagnosed with cerebral toxoplasmosis and HIV infection. His level of consciousness worsened, and the number of hemorrhagic lesions had increased in both hemispheres and the left thalamus on the computed tomography scan following two weeks of antitoxoplasma therapy. These newly discovered hemorrhagic lesions revealed in the CT had been found as the high intensity signal regions of initial fluid-attenuated inversion recovery magnetic resonance imaging. After five weeks of treatment, the hemorrhagic lesions gradually improved along with the patient's consciousness. Antiretroviral therapy was initiated six weeks following antitoxoplama therapy with reassurance that immune reconstitution inflammatory syndrome did not occur. After approximately four months of antitoxoplasma therapy, the patient was discharged into a group home with residual left hemiparesis on maintenance antitoxoplasma and antiretroviral therapy. Clinicians should recognize the delay of clinical and radiological improvement for hemorrhagic cerebral toxoplasmosis and patiently continue the antitoxoplasma therapy.