Occult posterolateral rotatory dislocation of the elbow with olecranon fracture in a child: a case report

ABSTRACT: INTRODUCTION: Acute posterolateral rotator elbow dislocation in a child is rare and can be easily misdiagnosed due to immaturity of the epiphysis. This is the first case of occult posterolateral rotator elbow dislocation in combination with an olecranon fracture. We report our experience with this case, which was not diagnosed correctly by plain radiographs. CASE PRESENTATION: An 11-year-old Asian boy suffered severe pain and swelling of his right elbow after his outstretched arm hit a car dashboard in a motor vehicle accident. Plain radiographs showed only a minimally displaced olecranon fracture and a tiny lateral epicondylar avulsion fracture. However, stress radiographs under general anesthesia revealed severe posterolateral rotatory instability. During surgery, we found that the cartilaginous lateral epicondylar apophysis was much larger than the epicondylar fragment on the radiographs. After the lateral epicondylar osteochondral fragment and lateral collateral ligament complex were fixed, the instability disappeared. CONCLUSION: Our experience with this case shows that it is important to check for instability with pediatric elbow fractures, because a tiny avulsion fracture was able to cause severe posterolateral rotatory instability in a child.     

大鼠咬合创伤牙周膜中MCP-1、ICAM-1的表达变化

目的:研究咬合创伤大鼠牙周组织中MCP-1、ICAM-1的表达情况。方法:12周龄雄性SD大鼠24只,随机分为4组(1个正常对照组和3个实验组),每组6只。正常对照组不作任何处理,实验组通过在大鼠左上颌第一磨牙颌面粘接树脂并内置不锈钢丝形成高出颌面0.6-0.8 mm的树脂层以建立同侧下颌咬合创伤实验动物模型,分别于建模后3、5、7 d处死各组大鼠,分离大鼠下颌组织,运用HE、Masson染色观察咬合创伤牙周组织形态变化,同时用免疫组织化学染色法检测MCP-1和ICAM-1的表达变化。结果:HE染色显示,正常组牙周膜纤维排列整齐,牙骨质表面较为平整,牙槽骨结构致密。实验组牙周膜纤维排列紊乱,牙周膜血管水肿充血、间隙改变,牙槽骨和牙骨质表面不平整,出现骨吸收。Masson染色显示,正常组牙周组织未见异常表现;实验组牙周膜纤维排列紊乱,可见水解断裂,局部有血流障碍和血管破裂。免疫组织化学显示,各实验组MCP-1和ICAM-1的表达变化均较正常对照组增多,差异有显著性(P0.05)。其中7 d组表达水平最高,与其他2组相比有统计学意义(P0.05)。结论:咬合创伤可引起大鼠牙周组织形态变化,MCP-1、ICAM-1的表达随时间呈现递增的趋势。     

NGF与Neuritin在脑外伤伴四肢骨折病人血清中的表达及意义

目的：通过检测脑外伤患者、脑外伤合并骨折患者、骨折患者及正常人外周血中NG3F,neuritin不同时间段的表达,根据其含量的变化,判断与骨折愈合速度的相关性,寻找骨折愈合的关键因子。方法：收集单纯脑外伤、单纯骨折患者各80例、脑外伤合并骨折患者60例、健康体检人群20例。选取外伤后3天、10天、2周抽取所有实验对象的静脉血,应用ELISA技术测定标本中NGF与Neuritin的含量。结果：损伤后每个时间段里,患者血清中NGF、neuritin含量有不同程度升高,均高于正常对照组,其中又以脑外伤合并骨折组最高。血清NGF在骨折合并脑外伤组伤后第3天含量明显升高,为（0．86±0．21）,伤后10天为（1．47±0．29）。14天为（2．07±0．21）,脑外伤合并四肢骨折组neuritin血清含量在伤后第3天略有升高为（83．47±18．85）,10天（108．50±31．65）,2周（91．86±21．12）．脑外伤合并骨折病人血清NGF、neuritin表达明显高于其他对照组,差别均有统计学意义（P〈0．05）。结论：脑外伤合并骨折病人血清NGF、neuritin表达明显高于其他对照组,说明与骨折愈合有着密切的相关性,两种因子可能在骨折愈合修复过程中共同起作用,从而,推测可能是脑外伤后骨折愈合加速的重要因素。     

Instability of the distal radio-ulnar joint: stabilization by a Gore-Tex ligament.

Diagnosis and treatment of problems caused by instability of the distal radio-ulnar joint are complex. In this retrospective study, the results of a uniform procedure by using a Gore-Tex ligament for stabilization of the distal radio-ulnar joint are presented. In eight patients, nine wrists were operated on. The mean age of the patients was 35 years. The dominant side was involved in six patients. The mean follow-up was 3.4 years. Three of nine wrist problems were of spontaneous onset. In these wrists, the final results were excellent. The other six wrists were operated on for problems after trauma: four patients after soft-tissue injury, one patient after distal radius fracture, and one patient after forearm fracture. Among these cases, one result was excellent, four were good, and another one was fair.     

Whisker exploration behaviours in the 5xFAD mouse are affected by sex and retinal degeneration

Active whisking in mice and rats is one of the fastest behaviours known in mammals and is used to guide complex behaviours such as exploration and navigation. During object contact, whisker movements are actively controlled and undergo robust changes in timing, speed and position. This study quantifies whisker movements in 6‐ to 7‐month old male and female 5xFAD mice, and their C57/SJL F1 wild‐type (WT) controls. As well as genotype, we examined sex differences and the effects of retinal degeneration (rd). Mice were filmed using a high‐speed video camera at 500 frames per second (fps), under infrared light while behaving freely in three tasks: object exploration, sequential object exploration and tunnel running. Measures of whisker position, amplitude, speed and asymmetry were extracted and analysed for each task. The 5xFAD mice had significantly altered whisker angular positions, amplitude and asymmetry during object contacts and female 5xFAD mice with rd had lower mean angular positions during object contact. There were no significant effects of genotype on sequential object exploration or on tunnel running but differences due to sex and rd were found in both tasks, with female mice making larger and faster whisker movements overall, and mice with rd making larger and faster whisker movements during object contact. There were sex differences in whisker movements during sequential object exploration and females with rd had higher whisker retraction speeds in tunnel running. These data show that measuring whisker movements can quantify genotype and sex differences and the effects of rd during exploratory behaviour in these mice.     

Trauma-induced changes in diaphyseal cross-sectional geometry in two elites from Copan, Honduras

This research utilized biplanar radiographs to estimate cross-sectional biomechanical properties for the skeletal remains of two elite individuals from the Early Classic period (ca. AD 400-600) of Copan, Honduras: K'inich Yax K'uk' Mo' (Hunal Burial 95-2), founder of the Early Classic Dynasty at Copan, and the primary female interment (Burial 37-8) from the Motmot tomb. Both individuals survived severe blunt-force insults to the right forearm. Gross skeletal examination and evaluation of the radiographs for K'inich Yax K'uk' Mo' suggest that these traumas resulted from, at least in part, disuse atrophy of the affected forearm skeletal elements. Gross and radiologic evaluation of the Motmot remains countered the possibility that she suffered from a metabolic bone disease, and confirmed the presence of a well-healed parry fracture of the right ulna. The degree of asymmetry in cross-sectional biomechanical properties reported here for K'inich Yax K'uk' Mo' is likely the secondary result of the described blunt-force trauma. The results obtained for the principal Motmot interment are not as dramatic, but suggest subtle changes to humeral cross-sectional geometry subsequent to trauma.     

A new genus and species of the subtribe Leptopsaltriina (Hemiptera: Cicadidae: Leptopsaltriini) from Vietnam,with a key to the genera of Leptopsaltriina

Vietanna Lee & Pham, gen. nov. and Vietanna hanoiensis Pham & Lee, sp. nov. are described based on a cicada specimen from Hanoi, Vietnam and placed in the subtribe Leptopsaltriina Moulton, 1923 of the tribe Leptopsaltriini Moulton, 1923 in the subfamily Cicadinae Latreille, 1802 (Hemiptera: Cicadidae). This new genus is morphologically similar to Tanna Distant, 1905 but distinguished from Tanna by the timbal cover exposing the inner part of timbal, the male abdominal epipleurite 3 with a distinct oblique linear fold, the male abdominal sternites without tubercle-like projections, and the aedeagus bifurcate at the apex. A key to the genera of Leptopsaltriina is provided.www.zoobank.org/urn:lsid:zoobank.org:pub:3B9CBC95-B54A-4BDE-A488-0DEAB69114BD.     

Effects of hypothermia and re-warming on the inflammatory response in a murine multiple hit model of trauma

INTRODUCTION: Although, hypothermia is a frequent event after trauma, it is unclear whether its beneficial or detrimental effects are more important. This study aims to quantify the effects of hypothermia and re-warming on the inflammatory response after fracture/hemorrhage and subsequent fracture stabilization with resuscitation. MATERIALS AND METHODS: Eighty-one male C57Bl/6 mice (aged 8-10 weeks, weighing 22.0+/-3.0 g) underwent femoral fracture and hemorrhage followed by resuscitation and splint fixation of the fracture. Animals were sacrificed 3h after induction of hemorrhage and fracture. Besides a sham group (n=6), four experimental groups were created: A: normothermia (n=12), B: hypothermia after trauma (n=21), C: re-warming after resuscitation and before stabilization (n=21), and D: hypothermia before trauma (n=21). Groups B-D were further subdivided into three subgroups according to the degree of hypothermia (subgroup 1: 35-33 degrees C, subgroup 2: 32.9-30.0 degrees C, and subgroup 3: 29.9-27.0 degrees C). Plasma cytokine (TNF-alpha, IL-6, and IL-10) and chemokine (MCP-1) concentrations were determined by ELISA, pulmonary permeability changes were quantified, and histological analysis of lung and liver tissues was performed. RESULTS: Normothermia resulted in a significantly increased early mortality rate. A significantly increased pro-inflammatory and decreased anti-inflammatory responses were also observed in normothermia as compared to hypothermia. The extent of these changes was most pronounced in the severe hypothermic group. Re-warming after mild hypothermia resulted in a pro-inflammatory response comparable to normothermia. CONCLUSION: Hypothermia has a beneficial effect on early survival after trauma, which appears to be independent of the level of hypothermia and re-warming. Re-warming, however, enhanced the pro-inflammatory response. Further studies with a longer posttraumatic observation period are required to investigate the long term effects of the hypothermia and re-warming-induced changes on the pro- and anti-inflammatory responses.     

Interhemispheric asymmetry in the functional organization of the prefrontal cortex in animals of different typologic groups

Rats allocated to groups by the method of "emotional resonance": rats which did and did not escape crying of a partner (A- and E-groups, respectively). Unit activity in the right and left prefrontal brain cortex (PFC) was recorded in these rats. The recorded neurons neurons were divided in two groups according to their reaction to a change in the level of food motivation. The so-called D-neurons decreased their activity after feeding of animals after a 24-hour food deprivation and the other group (I-neurons) increased its firing rate rate in this situation. It was shown that hemispheric distributions of D- and I-neurons are different in selected rat groups. In E-rats the I-neurons substantially predominated in the left hemisphere, whereas the D-neurons were more frequently recorded in the right one. No such asymmetry was observed in A-group of rats. During intracranial stimulation of emotionally positive brain structures I-neurons increased their firing rate, predominantly, in the left hemisphere, whereas during intracranial emotionally negative stimulation activation of the D-neurons predominated at the right. Features of the observed functional interhemispheric asymmetry of prefrontal cortex in A- and E-groups of rats were explained by differences in the interaction between hemispheres and dissimilar activation control.     

Developmental expression patterns of connexin26 and ‐30 in the rat cochlea

Connexin proteins form transmembranous gap junction channels that connect adjacent cells. Connexin26 and connexin30 have been previously shown to be strongly expressed in the inner ear of adult rats and to be mainly colocalized. Because intercellular connections by gap junction proteins are crucial for maturation of different tissues, we investigated the developmental expression of connexin26 and connexin30 in pre‐ and postnatal rats using immunocytochemistry. In the rat otocyst, staining for connexin26 as well as for connexin30 appeared at the 17th day of gestation. However, at this stage, expression of connexin30 was low and restricted to the neurosensory epithelium. Beginning from the 3rd postnatal day connexin26 and ‐30 were expressed with highest immunoreaction in the spiral limbus, the neurosensory epithelium, and between the stria vascularis and the spiral ligament. Beginning from postnatal day 12 the staining pattern resembled that of adult animals, with additional strong staining between all fibrocytes of the spiral ligament. Double labeling experiments demonstrated strongest colocalization of both connexins between the stria vascularis and the spiral ligament. These results demonstrate that development of the cochlear gap junction system precedes the functional maturation of the rat inner ear, which takes place between the 2nd and 3rd postnatal week. In the cochlea of a 22‐week‐old human embryo, connexin26 and connexin30 could be detected in the lateral wall, suggesting that both connexins also play a crucial role in function of the human inner ear. Dev. Genet. 25:306–311, 1999. © 1999 Wiley‐Liss, Inc.     

The effect of trauma on the structural-temporal organization of the T-dependent zone of a regional lymph node]

Experiments in 238 white mice have shown that after trauma there was a change in the population density (PD) of immune competent cells in the T-dependent zone of the regional lymph node (LN) both in the center of the deep cortex and in the T-territory adjacent to the germinative center. PD of small lymphocytes increases on the 1st-3rd days after trauma and returns to the initial level by the 4th-5th day. PD of mitotically dividing cells, immunoblasts, plasmablasts, immature and mature plasmocytes dramatically decreased on the 3rd day while an inconsiderable elevation of their PD took place on the 1st day in T-territory. The increased PD of small lymphocytes in the regional LN seems to be associated with their intensified release from the injury focus. The suppressed proliferation and differentiation of the plasmocyte line cells is the reaction to operation stress: in the posttraumatic period the spectral composition of fluctuations of PD of cells and parameters of its rhythmical components (both in the center of the deep cortex and in T-territory) were changed. As a rule, there was a displacement of acrophase and lessening of the rhythm amplitude. The general potency of the process after trauma increased. The amount of circadian components in the spectral composition of rhythmicity and their potency increased which speaks of central hormonal influences becoming greater.     

The causes and consequences of maxillofacial injuries in elderly people

Objective: The occurrence of trauma in older people is well‐documented; however the incidence of maxillofacial trauma is scarcely reported. Therefore, the objective of this study is to determine the causes and consequences of maxillofacial trauma in older people. Design: A five‐year (March 95 ‐ March 2000) retrospective study was earned out of all patients over the age of 65 years with facial trauma presenting to Accident and Emergency Department (A&E). The information was collected using the medical notes and discharge summaries. Setting: The Departments of A&E and Maxillofacial Surgery. Subjects: A total of 42 patients' records were examined for study related data. Results: A total of 42 patients were seen during the study period. Thirty‐six gave a history of a fall, of which 15 had tripped, 5 had slipped, 3 resulted from a Transient Ischaemic Attack (TIA), 1 as a result of alcohol abuse, in 1 a prosthetic knee gave way and 11 gave no cause for the fall. Of the remaining 6 patients. 5 were assaulted and 1 had a wardrobe fall on top of him. The majority of the falls occurred during the winter months. Maxillofacial injuries were noted in 27 of the 42 patients. Sixteen patients had cheekbone fractures, 8 mandibular fractures, 2 midface and 1 orbital complex fracture. Twenty‐five percent of cheekbone fractures and 50% of mandibular fractures were treated surgically. Medical history was noted in 27 patients. Conclusions: This study clearly demonstrates the majority of the facial trauma in the older people can be treated conservatively unless the patients complain of functional problems.     

A case of symbrachydactyly with oligodactyly

The term symbrachydactyly describes syndactyly accompanied by brachydactyly. Brachydactyly is seen in middle phalanges of both hands and feet and very short in length or absent. As for syndactyly it is a cutaneous type. It has always been observed unilaterally and sporadically. A familial type of this syndrome has also been reported. There have been many classifications of symbrachydactyly. Of these, Blauth classification is the most favored one. Yet these classifications have been inadequate to include many recently discovered other forms of symbrachydactyly. A three month old child was brought to the Istanbul University Genetic Research Center because of his abnormal hands and feet. He was the second child of a couple who had no kinship ties to each other. In the history of the family, there was no mention of any anomaly as such. There was a complete syndactyly involving the 3rd through the 5th fingers, partial syndactyly between the 2nd and 3rd, and the thumb was normal in the right hand. There was only one finger in the left hand. There was total syndactyly in four toes of the right foot with oligodactyly and absence of the big toe. The left foot had five toes with a complete syndactyly between the 2nd and the 3rd. Radiological observation indicated that the middle phalanges of both extremities were rudimentary or never developed. There was no osseous syndactyly. As observed in this case, oligodactylous type that is bilateral and involves both hands and feet together is very unusual. The purpose of this study is to present a rare case of this anomaly that requires a reassessment of symbrachydactyly and its traditional classifications.     

带线锚钉修复三角韧带损伤的效果及对患者踝关节功能的影响

目的:研究带线锚钉修复三角韧带损伤在踝关节骨折内固定治疗中的作用及对踝关节功能的影响。方法:回顾性分析2012年9月至2016年8月本院收治的72例裸关节骨折并三角韧带损伤患者并且行切开复位钢板置入内固定,及采取带线锚钉内固定方式修复三角韧带损伤视为观察组;另选取同期在本院进行踝关节骨折内固定治疗但不修复三角韧带的72例患者视为对照组。分析患者治疗前、治疗后1个月、3个月、6个月踝关节功能恢复情况,观察患侧内踝间隙和不良反应。结果:观察组在治疗后1个月、3个月、6个月的AOFAS评分显著高于对照组(P0.05)。观察组在治疗后6个月后的患侧内踝间隙显著小于对照组(P0.05)。结论:带线锚钉修复三角韧带损伤在踝关节骨折内固定治疗中,可明显降低患侧内踝间隙距离,可促进患者踝关节功能恢复,无严重不良反应,值得进一步广泛推广使用。     

Frequency and patterning of bone trauma in the late medieval population (13th-16th century) from Dugopolje, southern Croatia

The aim of this paper is to test the hypothesis of an increased level of interpersonal violence in Dugopolje during the late medieval period as testified by written sources. In order to accomplish this, an analysis and comparison of frequencies and patterning of long bone and craniofacial fractures between sex and age categories in the Dugopolje skeletal sample was performed. In total 209 excellently preserved adult skeletons were analysed: 111 males and 98 females. The total long bone fracture frequency is 1.5% (29/1910) with a significantly higher frequency in males compared to females. Most of the long bone injuries occurred as a result of accidents, probably due to rugged mountainous terrain, while a certain portion of trauma resulted from deliberate violence. Significantly higher fracture frequencies in males could be a result of a strict sexual division of labour where males performed more physically demanding and risky tasks, as witnessed by historical sources. 26 out of 119 complete adult crania (21.8%) exhibit skeletal trauma with significantly higher frequencies in males. Perimortem trauma was observed in one individual while antemortem healed sharp force lesions were registered in five individuals (all males). The predominance of frontal craniofacial injuries, as well as the presence ofperimortem trauma and sharp force lesions, suggests the presence of deliberate violence in this community. Although the indicators of deliberate violence were recorded predominantly in males, suggesting that intentional violence in Dugopolje was exclusively males' prerogative, the presence of nasal fracture in a female skeleton might point to a male towards female violence. Presented bioarchaeological data are in accordance with the written documents thus corroborating the claims of an increased level of deliberate interpersonal violence in the late medieval population from Dugopolje.     

髓核突出模型大鼠背根神经节中Wnt5a的表达

目的:观察Wnt5a在大鼠髓核突出模型的表达变化,探索Wnt5a在神经根病中的作用。方法:将80只成年雄性大鼠随机分为假手术组(Sham组,n=20)、髓核突出组(NP组,n=20)、髓核突出+生理盐水组(NP+Saline组,n=20)、髓核突出+益赛普组(NP+Etanercept组,n=20)。从大鼠尾椎椎间盘中取髓核,将髓核种植于L5背根神经节旁,制作髓核突出大鼠模型。采用免疫组织化学法分别检测各组大鼠背根神经节中的Wnt5a蛋白的表达,利用RT-PCR的方法分别检测各组大鼠背根神经节中Wnt5a m RNA的表达。结果:免疫组化结果显示,各组大鼠背根神经节的大中小神经元均有Wnt5a的表达,NP组较Sham组在3天、7天时Wnt5a表达量均增加(P0.01),3天和7天时NP+Etanercept组大鼠背根神经节中Wnt5a的表达量较NP+Saline组均减少(P0.01)。RT-PCR的结果与免疫组化的结果相符,表现为NP组较Sham组在3天、7天时Wnt5a mRNA的相对表达量增加(P0.01),NP+Etanercept组大鼠背根神经节中Wnt5a的相对表达量较NP+Saline组均减少(P0.01)。结论:髓核突出并压迫背根神节时,可引起背根神经节Wnt5a的表达增加,且阻断肿瘤坏死因子α(TNF-α)时,背根神经节的Wnt5a表达减少。     

Characteristic Features of Disorders of the Upright Posture in Patients with Poststroke Hemipareses

Characteristic features of upright posture maintenance and mechanisms of postural disorders in poststroke hemiparetic patients were studied using a bilateral force platform. The following features of postural disorders were revealed in the patients tested: an increase in the velocity and amplitude of the center-of-pressure (CP) sway as compared to in healthy subjects, an absolute decrease in the half-cycles of the CP sway, asymmetry of weight bearing by both feet, and a shift of the center of pressure of an affected foot towards the toe. The disturbance of stability of the vertical posture in such patients is to a greater extent associated with weight-bearing asymmetry. It was shown that the character of the CP sway is mainly determined by a disorder of the sensory motor control, whereas damage to the efferent pathways is responsible for the postural asymmetry. Increase in the muscle tone restricts the sway amplitude. Thus, several forms of postural instability are characteristic of hemiparetic patients. Predominantly sensory, motor, or tonic disorders are responsible for these disturbances of stability.     

基于磁共振多b值弥散加权成像对严重胸外伤预后的预测

目的:探讨基于磁共振(Magnetic Resonance Imaging,MRI)多b值弥散加权成像(Diffusion Weighted Imaging,DWI)对严重胸外伤预后的预测价值。方法:2018年2月-2020年6月选择在本院诊治的严重胸外伤患者76例(开放性损伤38例,闭合性损伤38例),所有患者都给予常规MRI扫描、多b值DWI扫描,记录成像质量与特征,判断预测价值。结果:所有患者都在胸外伤后3 d内进行检查,开放性损伤与闭合性损伤患者的MRI图像质量优良率都为100.0%,符合诊断要求。开放性损伤患者的多b值DWI之D*值、f值都显著高于闭合性损伤患者,而D值显著低于闭合性损伤患者,对比差异都有统计学意义(P<0.05)。在76例患者中,病理判断为胸腔后方韧带复合体1级损伤38例,2级损伤30例,3级损伤8例。MRI诊断为1级损伤39例,2级损伤31例,3级损伤6例,MRI诊断的准确性为93.4%。结论:基于MRI多b值DWI能清晰显示严重胸外伤的组织损伤情况,也能真实反映组织的微环境变化特征,能有效预测后方韧带复合体的损伤情况。     

Developmental expression patterns of connexin26 and -30 in the rat cochlea

Connexin proteins form transmembranous gap junction channels that connect adjacent cells. Connexin26 and connexin30 have been previously shown to be strongly expressed in the inner ear of adult rats and to be mainly colocalized. Because intercellular connections by gap junction proteins are crucial for maturation of different tissues, we investigated the developmental expression of connexin26 and connexin30 in pre- and postnatal rats using immunocytochemistry. In the rat otocyst, staining for connexin26 as well as for connexin30 appeared at the 17th day of gestation. However, at this stage, expression of connexin30 was low and restricted to the neurosensory epithelium. Beginning from the 3rd postnatal day connexin26 and -30 were expressed with highest immunoreaction in the spiral limbus, the neurosensory epithelium, and between the stria vascularis and the spiral ligament. Beginning from postnatal day 12 the staining pattern resembled that of adult animals, with additional strong staining between all fibrocytes of the spiral ligament. Double labeling experiments demonstrated strongest colocalization of both connexins between the stria vascularis and the spiral ligament. These results demonstrate that development of the cochlear gap junction system precedes the functional maturation of the rat inner ear, which takes place between the 2nd and 3rd postnatal week. In the cochlea of a 22-week-old human embryo, connexin26 and connexin30 could be detected in the lateral wall, suggesting that both connexins also play a crucial role in function of the human inner ear.     

Capacity for differentiation and normalization of tumor cell populations in transplantation into the anterior chamber of the eye. III. Rhabdomyosarcoma A-7 clones

Four clone lines of transplantable cell polymorphic rhabdomyosarcoma A-7 were investigated during transplantation to the subcutaneous connective tissue (SCT) and into eye anterior chamber (EAC). Cell morphology of transplants was studied by light and electron microscopy, the activity of their LDH M- and H-subunits was examined cytochemically, and the quantity of their nuclear DNA--cytophotometrically. In the case of A-7/1, A-7/2 and A-7/3 cell lines of EAC transplants we noticed a decrease in cell element kataplasia levels, differences in LDH M- and H-form ratio, reduction in the karyotype variability. Transplants of A-7/4 clone line were similar in SCT and EAC for all the signs studied. The results obtained show that the transplantable cell polymorphic rhabdomyosarcoma A-7 is heterogeneous for its differentiation and normalizing capacities during EAC proliferation. The data reported elsewhere concerning capability of four lines of murine rhabdomyosarcomas to normalize in EAC are discussed, and some possible mechanisms of this effect are regarded.