Stresses in growing soft tissues

Biochemical processes of tissue growth lead to production of new proteins, cells, and other material particles at the microscopic level. At the macroscopic level, growth is marked by the change of the tissue shape and mass. In addition, the appearance of the new material particles is generally accompanied by deformation and, consequently, stresses in the surrounding material. Built upon a microscopic toy-tissue model mimicking the mechanical processes of mass supply, a simple phenomenological theory of tissue growth is used in the present work for explaining residual stresses in arteries and studying stresses around growing solid tumors/multicell spheroids. It is shown, in particular, that the uniform volumetric growth can lead to accumulation of residual stresses in arteries because of the material anisotropy. This can be a complementary source of residual stresses in arteries as compared to the stresses induced by non-uniform tissue growth. It is argued that the quantitative assessment of the residual stresses based on in vitro experiments may not be reliable because of the essential stress redistribution in the tissue samples under the cutting process. Concerning the problem of tumor growth, it is shown that the multicell spheroid or tumor evolution depends on elastic properties of surrounding tissues. In good qualitative agreement with the experimental in vitro observations on growing multicell spheroids, numerical simulations confirm that stiff hosting tissues can inhibit tumor growth.     

Analysis of Skin Deformation Profiles During Sinusoidal Vibration of Fingerpad

Vibrotactile perception threshold measurement has been widely used to diagnose the severity of peripheral neuropathy associated with hand-arm vibration syndrome and sensory losses in stroke and diabetic patients. The vibration perception threshold is believed to be influenced by many factors, such as contact force and vibration frequency. The present study is intended to analyze, theoretically, the time-dependent deformation profile of skin surface, strain distributions within soft tissue, and response force of a fingertip when it is stimulated by a probe vibrating with a sinusoidal movement. A two-dimensional finite element model, which incorporates the essential anatomical structures of a finger: skin, subcutaneous tissue, bone, and nail, has been proposed to analyze the effects of vibration amplitude, frequency, and preindentation on the dynamic interaction between the fingerpad and vibrating probe. The simulation results suggest that the fraction of time over which the skin separates from the probe during vibration increases with increasing vibration frequency and amplitude, and decreases with increased preindentation of the probe. The preindentation of the probe has been found to significantly reduce the trend of skin/probe decoupling. The simulation results show reasonably consistent trends with the reported experimental data. © 2003 Biomedical Engineering Society. PAC2003: 8719Rr, 8719Bb, 8710+e     

组织液压波在大白鼠胃经皮下组织传送规律的研究

注射０．９％的生理盐水到麻醉的大白鼠胃经的皮下，形成一个水泡，然后给予一个机械压力，由此产生一个组织液压波，测量组织液压在胃经上和胃经外的变化，发现了五种基本的组织液型及亚型，这些波型基于组织不同的粘弹性特性，组织液压波在经线上与经线外幅度差异与距离的线性回归方程为Ｙ＝－０．３５Ｘ＋１．９６，具有统计学显著性（Ｐ＜０．０１）。表明经脉线组织可能具有较好的渗透性和柔性。     

Theoretical Study of the Effects of Vascular Smooth Muscle Contraction on Strain and Stress Distributions in Arteries

To study the effects of smooth muscle contraction and relaxation on the strain and stress distribution in the vascular wall, a mathematical model was proposed. The artery was assumed to be a thick-walled orthotropic tube made of nonlinear, incompressible elastic material. Considering that the contraction of smooth muscle generates an active circumferential stress in the wall, a numerical study was performed using data available in the literature. The results obtained showed that smooth muscle contraction affects the residual strains which exist in a ring segment cut out from the artery and exposed to no external load. When the ring specimen is cut radially, it springs open with an opening angle. The predicted monotonic increase of the opening angle with increasing muscular tone was in agreement with recent experimental results reported in the literature. It was shown that basal muscular tone, which exists under physiological conditions, reduces the strain gradient in the arterial wall and yields a near uniform stress distribution. During temporary changes in blood pressure, the increase in muscular tone induced by elevated pressure tends to restore the distribution of circumferential strain in the arterial wall, and to maintain the flow-induced wall shear stress to normal level. © 1999 Biomedical Engineering Society. PAC99: 8719Rr, 8719Ff, 8710+e     

细胞生长抑制因子与组织应力共同作用下的肿瘤初期生长阶段的二相模型

目的　探究细胞生长抑制因子和组织应力对处于初期生长阶段肿瘤的影响。方法　将处于初期生长阶段的实体肿瘤分为肿瘤细胞相和间质相，采用二相模型描述其生长、演变过程组织间营养的供给促进肿瘤细胞的生长；新陈代谢及细胞自身分泌的抑制因子加速细胞的凋亡。建立肿瘤细胞相的连续胜方程与营养、抑制因子的扩散方程。考虑到两相的互相作用对肿瘤生长的影响，建立两相的力平衡方程，并利用各相的本构关系确定最终耦合的质量守恒方程、动量守恒方程和扩散方程，进行数值求解。结果　数值计算结果显示，营养物质浓度随时间增加而减小，其分布由肿瘤中心向周边递增；抑制因子的含量随时间推进而减少，在肿瘤中心区域变化明显，周边变化不大；在抑制因子与组织应力的共同影响下，生长初期阶段肿瘤的中心区域活性小，周边区域活性大；忽略抑制因子的作用。肿瘤内部活性很高且肿瘤细胞分布均匀。结论　抑制囚子的存在，使生长初期阶段的肿瘤内部出现坏死区；间质挤压肿瘤细胞，细胞产生释放应力的趋势，从而向外生长。     

Computer aided speckle interferometry: a technique for measuring deformation of the surface of the heart

An investigation of the inhomogeneous and anisotropic properties of myocardium necessitates a whole field measurement technique with high spatial resolution. Computer aided speckle interferometry (CASI) may be applied to measuring deformation on the epicardial surface of the heart. Silicone carbide particles (approximately 40 m in diameter) were sprinkled randomly onto the epicardial surface of isolated rabbit hearts. When illuminated with white light, speckles may be observed with a charge coupled device (CCD) camera. A balloon was placed in the left ventricle to control the intracavitary load on the arrested heart. To compare CASI to the gold standard technique of sonomicrometry, two ultrasonic transducers were implanted into the wall of the myocardium. Three hearts were exposed to various loading conditions, and at each condition speckle images were recorded. CASI was used to determine the distribution of displacement vectors (both direction and magnitude) in the region imaged by the CCD camera. Strain along the axis of the implanted transducers was determined with CASI and compared to that obtained with sonomicrometry. Strain determined from CASI and sonomicrometry produced equivalent results. Unlike sonomicrometry, whereby the displacement between two points with a relatively large gauge length is obtained, CASI is able to determine displacement vectors for hundreds of points within the same region. In conclusion, CASI produced equivalent results to those obtained from sonomicrometry (although not with the same temporal resolution), but it is a whole field deformation mapping technique that has a spatial resolution three orders of magnitude higher than that of sonomicrometry. © 2001 Biomedical Engineering Society. PAC01: 8763Lk, 8719Hh, 8719Rr     

Simultaneous Measurement of Interstitial Fluid Pressure and Load in Rat Skin After Strain Application <Emphasis Type="Italic">In Vitro</Emphasis>

Skin provides the flexible, protective covering of the body. It consists of a network of fibrous proteins embedded in a viscoelastic gel. Theoretical models of soft tissue demonstrate that behavior of such systems is strongly influenced by the relationship between the interstitial fluid pressure (P_if) and solid matrix stress. A microtensiometer for loading skin uniaxially in vitro was, therefore, developed and used in conjunction with the established servo-null micropipette technique to measure P_if. Dorsal rat skin specimens were preloaded to 100 mN, where P_if was 2.3±1.3 mm Hg (mean±SE, n=12) above ambient, and then strained by 4%. Load instantaneously increased and the subsequent decay was described by the function, F(t)=F(1)[1-C_fLn(t)]. F(1), related to the instantaneous elasticity, was 272 ± 42 mN (n=12) while, C_f was 0.0894 ± 0.0026 [Ln(s)]_-1 (n=12). A similar function P(t)=P_s(1)[1-C_psLn(t)], where P_s(1)=27 ± 5 mm Hg and C_ps=0.1274 ± 0.0097 [Ln(s)]_-1 (n=12) fitted the decay of P_if after 20 s with a residual 0.82, though, P_if fell more rapidly over the initial 10 s. P_if and stress can be measured simultaneously with the apparatus, though more precise determination of the depth at which pressure is measured is required for quantitative comparison of the magnitude of these two parameters. © 2003 Biomedical Engineering Society. PAC2003: 8719Rr, 8719Tt     

一种针刺补泻法对小型猪皮下组织液压的影响

目的研究《灵枢》卷首《九针十二原》针刺补泻法对小型猪皮下组织液压(interstitial fluid pressure,IFP)的作用,探讨其调节组织液的生物力学机制。方法在9只健康实验用小型猪腹部随机取点行补法(提/按法)和泻法(摇大针孔),观察正常状态(normal state,NS)、抽取组织液的低组织液量(low volume,LV)状态和注入生理盐水的高组织液量(high volume,HV)状态下针刺前后IFP。结果 NS下提/按法可极显著升高IFP;泻法可极显著降低IFP,针后5 min泻法组IFP降低较快。LV状态提/按法均能升高IFP,针后10 min二者IFP下降较慢。HV状态下泻法可极显著降低IFP,针后5 min与对照组变化趋势不同。结论该补泻法可升高或降低IFP,证明其对IFP有相反方向的调节作用。研究结果为针灸临床使用补泻手法提供新的科学依据。     

胃癌患者外周血及癌组织中上皮细胞黏附分子和存活素的表达及意义

目的:观察胃癌患者外周血及癌组织中上皮细胞黏附分子(EP-CAM)及存活素的表达水平及探讨其在胃癌发生及发展中的临床意义。方法:采用RT-PCR检测正常对照组和胃癌组患者外周血EP-CAM及存活素mRNA水平;免疫组化法观察癌旁上皮组织和胃癌组织中EP-CAM及存活素蛋白表达。结果:正常对照组外周血EP-CAMmRNA相对表达水平为0.05±0.01,存活素mRNA相对表达水平为0.02±0.01,胃癌组EP-CAM相对表达水平为0.82±0.02,存活素相对表达水平为0.61±0.04,两者均显著高于正常对照组(P<0.01);癌旁上皮组织中EP-CAMMOD为0.005±0.001,存活素MOD为0.004±0.001,胃癌细胞EP-CAM的MOD为0.309±0.054,存活素MOD为0.331±0.066,两者均显著高于癌旁对照组织(P<0.01)。结论:EP-CAM及存活素mRNA和蛋白高表达可能参与了胃癌的发生发展。     

应力环境对大鼠股骨生长与重建和力学性能的影响

通过创建一种新的动物模型，研究应力环境对生长期大鼠股骨生长与重建，以及对其力学性能的影响，并探讨其作用机理。切断6周大SD大鼠右后肢的坐骨神经，致使其右后肢残废，为废用组；左后肢过度负重，为过载组；正常大鼠为对照组。每天早午晚鼓励动物运动半小时，4周后结束实验观测。测量股骨中段的宏观几何学参数、物理学参数和生物力学参数。实验发现：与对照组相比，实验组股骨的若干几何及物理参数发生了明显变化，表明应力环境可以改变活骨组织的成份和结构并逐渐改变其力学性能。实验结果表明，本研究提出的实验模型实用且可靠。     

Capillary hemangioblastoma of soft tissue: report of a case and review of the literature

Capillary hemangioblastoma (CH) is a tumor of unknown histogenesis that arises primarily in the posterior cranial fossa, either as a sporadic event or in association with von Hippel-Lindau disease. To date, only 6 examples of a tumor with morphological features of CH arising in the somatic soft tissues have been documented in case reports and small series, and 3 of these tumors were associated with a peripheral nerve. Herein, we report a case of CH arising in the gastrocnemius muscle and not associated with a peripheral nerve in a 53-year-old woman with no clinical stigmata or family history of von Hippel-Lindau disease.     

Composite Tumor Consisting of Dermatofibrosarcoma Protuberans and Giant Cell Fibroblastoma Associated with Intratumoral Endometriosis

We present a unique case of composite skin tumor of the vulva consisting of dermatofibrosarcoma protuberans (DFSP) and giant cell fibroblastoma (GCF) with an intratumoral focus of endometriosis.A 31-year-old female with a 10-year-history of a recurring subcutaneous tumor in the vulvar area underwent excision of the seventh recurrence of the tumor. Microscopic examination revealed a composite fibrohistiocytic tumor consisting of DFSP and GCF. Additionally, a focus of endometriosis within the tumor tissue was found.Malignant transformation of extragonadal endometriosis has already been described; we present, however, the occurrence of a focus of endometriosis within the tissue of a hormonally independent soft tissue tumor. There is a possible link to the occurrence of cutaneous endometriosis at previous surgery sites and in the scars. The presence of endometriosis within the soft tissue tumor represents, to the best of our knowledge, a previously undescribed collision phenomenon.     

伴破骨样巨细胞平滑肌肉瘤的临床病理学观察

目的 探讨伴破骨样巨细胞平滑肌肉瘤的临床病理学特点及其鉴别诊断.方法 收集7例伴大量破骨样巨细胞平滑肌肉瘤病例的临床和影像学资料,行光镜观察、免疫组织化学(EnVision法)标记和电镜观察,并复习相关文献.结果 患者均为成年人,其中女性3例,男性4例,平均年龄 63岁.肿瘤位于大腿皮下软组织2例,左背部、腹膜后、小肠、乳腺和子宫各1例.组织学上,所有病例均由形态相对一致、呈交织条束状排列的梭形瘤细胞和大量的破骨样巨细胞组成,后者多散在分布于梭形细胞之间(6例),或形成巨细胞瘤样结节(1例).免疫组织化学标记显示,梭形细胞程度不等地表达平滑肌肌动蛋白、肌特异性肌动蛋白、结蛋白和高相对分子质量钙调结合蛋白,破骨样巨细胞表达CD68.电镜观察显示梭形细胞具平滑肌分化特征,破骨样巨细胞则具组织细胞分化.随访6例患者,均在术后发生复发或转移,其中3例带瘤生存,2例死亡.结论 (1)伴大量破骨样巨细胞的平滑肌肉瘤是平滑肌肉瘤的一种少见亚型,形态上与巨细胞型恶性纤维组织细胞瘤相似,诊断时应注意加以鉴别.(2)免疫组织化学标记和电镜观察提示肿瘤内的破骨样巨细胞起源于单核细胞/组织细胞系.(3)该肿瘤的恶性程度高,预后差.

Abstract：

Objective To study the clinicopathologic features of leiomyosarcoma with prominent osteoclast-like giant cells. Methods The clinical and pathologic features of 7 cases of leiomyosarcoma with prominent osteoclast-like giant cells were analyzed. Immunohistochemical and ultrastructural studies were performed. The literature was reviewed. Results All cases occurred in adults, with a mean age of 63 years. There was no significant soft tissue of thigh (number=2), left back (number=1), retroperitoneum (number=1), small intestine (number=1), breast (number=1) and uterus (number=1). Histologic examination showed that the tumor was composed of relatively uniform spindly cells arranged in interlacing fascicles. The hallmark was the presence of prominent osteoclast-like giant cells, either intimately admixed with the spindly cells (number=6) or forming giant cell tumor-like nodules (number=1). Immunohistochemically, the spindly cells expressed smooth muscle actin, muscle-specific actin, desmin and h-caldesmon in various degrees, whereas the osteoclast-like giant cells expressed CD68. Ultrastructural study showed smooth muscle differentiation in the spindly cells and histiocytic differentiation in the osteoclast-like giant cells. Follow-up data were available in 6 cases. There were local recurrences and/or metastases in all the 6 patients. Three patients were alive with unresectable or recurrent/metastatic disease and two patients died of the disease. Conclusions Leiomyosarcoma with prominent osteoclast-like giant cells is a rare variant of leiomyosarcoma which should be distinguished from the so-called giant cell variant of malignant fibrous histiocytoma. The osteoclast-like giant cells are of histiocytic differentiation. Surgical resection remains the mainstay of management of this high-grade sarcoma.     

一种骨种子细胞体外应力培养系统的建立

目的建立体外应力培养系统，观察应力刺激对骨种子细胞成骨分化的影响。方法选择具有明确成骨分化潜能的间充质干细胞(MSCs)作为种子细胞，以脱细胞骨基质为支架材料，以流体切应力作为对种子细胞的体外应力刺激。建立一种骨种子细胞体外三维应力培养系统——流动腔灌流体系，并利用该系统对MSCs的碱性磷酸酶(ALP)活性和骨钙素产物的影响进行评价。结果该系统可以明显促进ALP活性和骨钙素产物的表达，而细胞计数无明显改变。结论本系统为骨组织工程研究提供了一种有效的体外培养模型。     

上皮样肉瘤样血管内皮瘤的临床病理学观察

目的 探讨上皮样肉瘤样血管内皮瘤的临床病理学特征和鉴别诊断.方法 回顾性分析3例上皮样肉瘤样血管内皮瘤的临床表现、组织学特点和免疫表型.结果 3例均发生于成年男性,分别因左颈部肿块、髂部疼痛和双侧颈肩区复发性肿块就诊.镜下观察肿瘤由梭形和上皮样的细胞组成,两种细胞在形态上有移行.瘤细胞呈片状、模糊结节状或交织条束状排列,间质伴有胶原化.1例于结节中央可见凝固性坏死,形态上类似上皮样肉瘤.3例肿瘤内均无明显的血管形成,但其中1例于局灶区域可见胞质内空泡形成,类似上皮样血管内皮瘤.免疫组织化学标记,瘤细胞同时表达上皮性标记和内皮标记.3例均经手术切除,其中2例患者术后恢复良好,随访18个月和14个月均健在,无局部复发或远处转移,另1例术后6年内复发5次.结论上皮样肉瘤样血管内皮瘤属于一种少见的中间型血管内皮瘤,兼具上皮样肉瘤和上皮样血管内皮瘤的部分形态.仅凭光镜形态有时较难确定其内皮细胞分化,必须借助于免疫组织化学标记.上皮样肉瘤样血管内皮瘤与上皮样血管内皮瘤关系较为密切,可能是后者的一种富于细胞性梭形细胞变型.

Abstract：

Objective To study the clinicopathologic features and differential diagnosis of epithelioid sarcoma-like hemangioendothelioma (ES-H). Methods The clinical, radiologic and pathologic features of three cases of ES-H were analyzed. Results All the 3 cases occurred in male adults. The age ranged from 44 to 53 years. The presentations included left neck mass, iliac pain and bilateral shoulder masses. Histologically, ES-H was composed of a mixture of spindle and epithelioid tumor cells. Transition between the two cell types was demonstrated. The tumor cells were arranged in compact sheets, vague nodules or intersecting fascicles, amongst a collagenous stroma. Central coagulative necrosis was identified in one case, reminiscent the morphology that seen in epithelioid sarcoma. There was no evidence of angiogenesis, though focal presence of intracytoplasmic vacuoles was seen in one case, as in classic examples of epithelioid hemangioendothelioma. Immunohistochemical study showed that the tumor cells expressed both epithelial (AE1/AE3, CAM5.2 and epithelial membrane antigen) and endothelial (CD31,Fli-1 and factor Ⅷ-related antigen ) markers. Two of the cases were also positive for CD34. All of the patients were treated by surgical resection. Two patients remain well at 14-month and 9-month follow up,respectively. The remaining patient had repeated local recurrences during a 6-year period. Conclusions ES-H represents a rare morphologic type of hemangioendothelioma. It has some overlapping histologic features with epithelioid sarcoma and epithelioid hemangioendothelioma. The endothelial nature of ES-H is difficult to be verified on the basis of morphologic examination alone. Confirmation of the diagnosis with immunohistochemistry is necessary. ES-H is likely related to epithelioid hemangioendothelioma and may represent a cellular spindie cell variant of epithelioid hemangioendothelioma.     

封闭负压引流术治疗下肢骨折骨外露伴大面积软组织损伤的护理效果观察

研究封闭负压引流术治疗下肢骨折骨外露伴大面积软组织损伤患者的护理效果。方法 回顾分析2016年8月~2017年8月在我院采用封闭负压引流术治疗的116例下肢骨折骨外露伴大面积软组织损伤患者临床资料,随机分为对照组和观察组,各58例。对照组应用常规护理,观察组应用针对性护理干预,观察两组患者临床效果、伤口愈合时间、住院时间、换管次数及并发症发生情况。结果 观察组治疗总有效率为96.55%,高于对照组的79.31%,差异有统计学意义（P＜0.05）;观察组在愈合时间、住院时间、换管次数均优于对照组,差异有统计学意义（P＜0.05）。观察组并发症发生率为1.72%,低于对照组的8.62%,差异有统计学意义（P＜0.05）。结论 针对性的护理干预在封闭负压引流术治疗下肢骨折骨外露伴大面积软组织损伤中,对并预防发症的发生,缩短住院时间,损伤的愈合有积极作用。     

Association Between Hemodynamic Profile During Laboratory Stress and Ambulatory Pulse Pressure

Hemodynamic responses underlying blood pressure reactivity to laboratory stress are theoretically linked to cardiovascular pathophysiology. The present study investigated whether a vascular response predicted ambulatory pulse pressure, a known risk factor for cardiovascular disease. A new model of hemodynamic profile, previously developed by the authors, was applied to 24-h ambulatory data from 30 female and 34 male healthy young adults. Of these, 40 were monitored during a naturalistic stressor (university examination). For females, hemodynamic profile significantly predicted nighttime systolic blood pressure, and 24-h, day-, and nighttime diastolic blood pressure, but not ambulatory pulse pressure. A vascular or mixed hemodynamic profile significantly predicted 24-h and daytime ambulatory pulse pressure in males. The findings are consistent with theories of pathogenic mechanisms involving vascular changes and suggest that, for males, a vascular or mixed hemodynamic profile measured during laboratory stress may be a risk marker for cardiovascular disease, by its association with ambulatory pulse pressure.     

背部皮肤软组织放线菌病一例并文献回顾

目的探讨皮肤软组织放线菌病的临床表现、诊断、鉴别诊断及治疗，提高创面外科医师对皮肤软组织放线菌病的认识。 方法报道1例背部皮肤软组织放线菌病的诊治经过，分别以"放线菌、放线菌感染、皮肤、软组织"及"actinomycosis，cutaneous，soft tissue"为检索词检索中国知网和PubMed的相关文献并进行分析。 结果与所检索20篇文献相比，本例皮肤放线菌病的临床表现、鉴别诊断及治疗既典型又具自身特点。本例患者入院时并未表现出明显皮肤肿物，但皮下感染组织内多个窦道，伴较多土褐色脓液流出较为典型。本例患者入院第9天才培养出放线菌，但无论是术中肉眼观察、细菌培养还是组织病理学检查均未见典型"硫磺颗粒"。本例患者查体、术中所见及辅助检查结果和气性坏疽的临床表现高度相似，因此最初曾高度怀疑产气荚膜梭菌感染，但多次细菌培养及涂片均未提示产气荚膜梭菌感染。治疗主要包括全身状态的调整、手术清创及抗生素的应用。 结论原发于皮肤软组织的放线菌病较少见，临床表现多样，即便有相对典型特征，也并无特异性，诊断需综合考虑并鉴别诊断。皮肤软组织放线菌感染发病率低，不易诊断，需引起创面外科医师的注意，及早对本病作出诊断及治疗。     

Planar Biaxial Creep and Stress Relaxation of the Mitral Valve Anterior Leaflet

A fundamental assumption in mitral valve (MV) therapies is that a repaired or replaced valve should mimic the functionality of the native valve as closely as possible. Thus, improvements in valvular treatments are dependent on the establishment of a complete understanding of the function and mechanical properties of the native normal MV. In a recent study [Grashow et al. ABME 34(2), 2006] we demonstrated that the planar biaxial stress–strain relationship of the MV anterior leaflet (MVAL) exhibited minimal hysteresis and a stress–strain response independent of strain rate, suggesting that MVAL could be modeled as a “quasi-elastic” material. The objective of our current study was to expand these results to provide a more complete picture of the time-dependent mechanical properties of the MVAL. To accomplish this, biaxial stress-relaxation and creep studies were performed on porcine MVAL specimens. Our primary finding was that while the MVAL leaflet exhibited significant stress relaxation, it exhibited negligible creep over the 3-h test. These results furthered our assertion that the MVAL functionally behaves not as a linear or non-linear viscoelastic material, but as an anisotropic quasi-elastic material. These results appear to be unique in the soft tissue literature; suggesting that valvular tissues are unequalled in their ability to withstand significant loading without time-dependent material effects. Moreover, insight into these specialized characteristics can help guide and inform efforts directed toward surgical repair and engineered valvular tissue replacements.     

Structural Changes in the Nucleus Ambiguus of the Medulla Oblongata and Intracardiac Ganglia in Growing Rats in Immobilization Stress

The aim of the present work was to study qualitative and quantitative measures of histological changes in the nucleus ambiguus (NA) of the medulla oblongata and the cardiac autonomic ganglia (CAG) in growing animals in conditions of immobilization stress of different durations. Experiments were performed on 56 mongrel white rats aged 30 days. Immobilization stress was produced by placing rats in a special apparatus with a controllable internal volume for 3, 7, 15, and 30 days. The NA and CAG were studied on paraffin sections using neurohistological methods and quantitative analysis. Morphological and morphometric changes, consisting of a delay in the growth of neurocyte cell and nucleus volumes, as compared with controls, were seen both in the NA of the medulla oblongata and the CAG and were evaluated as impairments in the histogenesis of nerve tissue during postnatal ontogenesis. The extent of structural changes in these components of the autonomous nervous system was directly dependent on the duration of the experimental treatment. __________ Translated from Morfologiya, Vol. 127, No. 1, pp. 21–24, January–February, 2005. Director Professor M. Yu. Kapitonova Director Professor V. B. Pisarev