Skeletal alterations in hypophysectomized rats: I. A histomorphometric study on tibial cancellous bone

Background: Hypophysectomy (HX) results in a cessation of bone growth and a decrease in bone metabolism. The purpose of this study is to examine the effect of HX on the static and dynamic histomorphometry of cancellous bone in the secondary spongiosa of the proximal tibial metaphysis in rats. Methods: Female rats, at 2 or 3 months of age, were HX and sacrificed at 0, 5 days, 2 and 5 weeks after the surgery. Age-matched intact rats served as controls. Cancellous bone histomorphometry was performed on doublefluorescent labeled, 30-um-thick sections of the proximal tibia. Tartrateresistant acid phosphatase histomorphometry was performed at 5 days on HX and control rats to evaluate the resorption in the metaphyseal bone. Results: Although the intact rats gained in body weight, tibial length, tibial weight, and density after 5 weeks, these changes did not occur following HX. As compared to the basal group, HX resulted in a decrease in the density and dry weight of the metaphysis. The histomorphometric data showed that the cancellous bone volume and trabecular number of the secondary spongiosa were decreased and the separation was increased in the HX rats. The dynamic results showed that HX significantly decreased longitudinal growth rate and tissue-based bone formation and resorption. However, the bone surface-based eroded surface, labeled surface, the mineral apposition rate, and the bone formation rate did not differ between the intact and the HX rats at either the 2 or 5 weeks study. Five days after HX, the bone surface and tissue-based osteoclast surfaces were significantly lower in the HX than in the intact rats. Conclusions: Pituitary hormone deficiency results in cancellous bone loss. The bone loss is due primarily to the suppression of longitudinal growth-dependent bone gain and the inhibition of tissue-based bone turnover with a lower bone formation relative to bone resorption. The surfacebased bone turnover is not affected. © 1995 Wiley-Liss, Inc.     

强力霉素影响基质金属蛋白酶活性和血管重构的实验研究

目的：观察强力霉素对损伤动脉组织中基质金属蛋白酶（MMP）活性的抑制作用，并探讨强力霉素对血管平滑肌细胞增殖、动脉内膜增生、管腔重构的影响。方法:球囊导管扩张动脉的方法建立大鼠颈总动脉损伤模型。治疗组用强力霉素30 mg·kg^-1·d^-1干预。明胶酶谱法测定损伤动脉组织中MMPs的活性。用HE染色、VVG染色、免疫组化标记α-actin和增殖细胞核抗原的方法观察损伤动脉内膜厚度、管腔重构及平滑肌细胞增殖的情况。结果:①强力霉素治疗组MMP-9活性在术后24 h、3 d分别比对照组低26.3％、34.5％（P<0.01）；MMP-2活性在术后7 d比对照组低40.0％（P<0.01）。②强力霉素治疗使术后7 d内膜平滑肌细胞增殖率（43.23％±1.06％）显著低于对照组（62.76％±1.02％）（P<0.01）；使术后14 d、28 d新生内膜厚度比对照组分别少32.0％、38.8％（P<0.01），而管腔面积比对照组多58.0％、90.4％（P<0.01） 。结论：强力霉素可以显著降低血管损伤后MMPs活性，抑制内膜平滑肌细胞的增殖、新生内膜增生以及管腔重构，提示它可能具有防治PTCA术后再狭窄的作用。     

Analysis of dynamic cerebral autoregulation using an ARX model based on arterial blood pressure and middle cerebral artery velocity simulation

The study aimed to model the cerebrovascular system, using a linear ARX model based on data simulated by a comprehensive physiological model, and to assess the range of applicability of linear parametric models. Arterial blood pressure (ABP) and middle cerebral arterial blood flow velocity (MCAV) were measured from 11 subjects non-invasively, following step changes in ABP, using the thigh cuff technique. By optimising parameters associated with autoregulation, using a non-linear optimisation technique, the physiological model showed a good performance (r=0.83±0.14) in fitting MCAV. An additional five sets of measured ABP of length 236±154 s were acquired from a subject at rest. These were normalised and rescaled to coefficients of variation (CV=SD/mean) of 2% and 10% for model comparisons. Randomly generated Gaussian noise with standard deviation (SD) from 1% to 5% was added to both ABP and physiologically simulated MCAV (SMCAV), with ‘normal’ and ‘impaired’ cerebral autoregulation, to simulate the real measurement conditions. ABP and SMCAV were fitted by ARX modelling, and cerebral autoregulation was quantified by a 5 s recovery percentage R5% of the step responses of the ARX models. The study suggests that cerebral autoregulation can be assessed by computing the R5% of the step response of an ARX model of appropriate order, even when measurement noise is considerable.     

Mucosal bromodomain-containing protein 4 mediates aeroallergen-induced inflammation and remodeling

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IPFM，MIPFM模型产生的仿真心率变异性信号的周期图与AR谱分析研究

为了研究不同心电序列转换方式及不同谱估计方法对心率变异性（ＨＲＶ）信号谱分析结果的影响，本文对积分脉冲频率调制（ＩＰＦＭ）模型及修正积分脉冲频率调制（ＭＩＰＦＭ）模型在输入不同振幅与频率的正弦信号时所产生的随机点过程，用两种心电序列转换方法进行转换得到仿真ＨＲＶ信导；然后，采用周期图与自回归（ＡＲ）谱估计方法计算这种厉真ＨＲＶ信号的功率谱。研究结果表明：①对于ＭＩＰＦＭ模型产生的随机点过程，同一心电序列转换方法所得出的仿真ＨＲＶ信号的ＡＲ谱与周期图的谱峰功率估计基本一致；而对ＩＰＦＭ模型则不完全一致。②ＭＩＰＦＭ模型仿真实验表明，对实际ＨＲＶ信号谱分析，使用低，高频谱峰功率比（ＲＦ）作为反映心脏自主神经张力平衡的指标时，除心电序列传换及谱估计方法可能造成的误差外，当低频谱峰靠近极低频谱峰时，根据ＲＦ值解释生理实验结果会有校大误差。③座分析实际ＨＲＶ信号的工作中，不同心电序列转换方式产生的伪谐波对ＨＲＶ谱分析结果的影响不大。     

压力超负荷大鼠心、肺、肾血管重构的动态研究

目的 探讨压力超负荷与大鼠心、肺、肾内小动脉形态学重建的关系。方法 采用缩窄腹主动脉造成大鼠压力负荷模型，将大鼠随机分为两组：假手术组（SOG)和手术组(OG)。每组分为术后1、2、4、7、14、21、30、45、60d 9个时间点，对大鼠心、肺、肾组织连续切片，采用光镜配合计算机图像分析技术检测三个脏器小动脉几何形态的动态改变。结果 (1)随着压力负荷的增加，心、肺、肾小动脉的形态学重建可能存在时间顺序。(2)平均动脉压和造模时间与小冠状动脉和肾小动脉的壁腔比显著相关，而对小冠状动脉的管壁面积无影响；收缩压和造模时间与肾小动脉的管壁面积显著相关；造模时间与肺小动脉的壁腔比和管壁面积显著相关。结论 压力超负荷与心、肺、肾小血管的动态重构关系密切。小冠状动脉的重建以中膜平滑肌细胞的重排为主，肺、肾内小动脉的重建则可能存在中膜平滑肌细胞的肥大和增殖。     

Increased levels of serum tissue inhibitor of metalloproteinase-1 but not metalloproteinase-3 in atopic dermatitis

Matrix metalloproteinases and their specific inhibitors, tissue inhibitors of metalloproteinases (TIMPs), contribute to inflammation-induced tissue destruction and subsequent remodeling for maintenance of tissue homeostasis. Since the production of these enzymes and their inhibitors is regulated by mediators such as proinflammatory cytokines and growth factors, elevated levels of serum TIMPs and/or MMPs have been documented in patients with several inflammatory disorders. In this study, we examined the role of TIMPs and MMPs in the pathogenesis of atopic dermatitis (AD) by evaluating the serum levels of TIMP-1 and MMP-3 in 40 patients with AD and 20 control subjects by ELISA. The serum TIMP-1 levels were significantly higher in AD patients in exacerbation status than in nonatopic subjects, whereas serum MMP-3 levels were not significantly different between them. As a result, AD patients revealed significantly elevated TIMP-1/MMP-3 ratios. The levels of serum TIMP-1 were significantly reduced in AD patients following conventional treatments. Significantly higher values of peripheral eosinophil counts, serum levels of IgE and lactate dehydrogenase, eruption score, and eruption area were noted in the AD patients with elevated TIMP-1 levels when compared with those with normal values. Moreover, the points of chronic eruptions such as lichenification and prurigo were significantly higher in the patients with elevated TIMP-1 levels than those with normal TIMP-1, while those of acute lesions such as oozy/microvesicles and oedema were not different between these groups. Serum TIMP-1 level may be a useful marker to estimate the long-term disease activity of AD.     

Profilin-mediated food-induced allergic reactions are associated with oral epithelial remodeling

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Program for generation of three-dimensional finite element mesh from magnetic resonance imaging scans of human limbs

A PC-AT based program for conversion of magnetic resonance imaging (MRI) scans into coordinate input for finite element mesh generation is presented. The program is written in Borland C + +3.1 and is compatible with every general-use personal computer, permitting the use of MS-DOS 3.0 or higher with a Microsoft mouse. The program is menu driven and does not demand specialised knowledge from the user. The system and memory requirements are minimal -- 640 kB RAM -- and it runs as a stand-alone program. A second program allows the construction of a three-dimensional representation of the limb sub-structure and generation of the FE mesh from the converted cross-sectional scans. The capabilities of the program are demonstrated using cross-sectional scans of the upper arm; the fat, muscle and bone contours were obtained to a very high level of precision (0.4 mm).