Biomechanical activity of the growth plate

Summary The authors analyze at several levels the biomechanical activity of the epiphyseal plate.From a histologic point of view, they show the role played by the different cell layers in growth.The rapid growth of long bones is well known in animals, not entirely in human beings. The factors involved in mechanical regulation of the epiphyseal plate are analyzed according to distraction and compression stresses. Other factors have also been reported (periosteum and muscle).Analysis of the literature reveals that biomechanical activity and the factors managing growth are not well known yet.A combined effort should be made to obtain better understanding of the surgical procedures carried out in pediatric orthopedics.

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Comportement biomécanique du cartilage de croissance. Incidences cliniques

Résumé Les auteurs analysent le comportement biomécanique du cartilage de croissance à plusieurs niveaux.Sur le plan histologique ils montrent le rôle joué dans la croissance par les différentes couches cellulaires.La vitesse de croissance des os longs est bien connue chez les animaux et difficile à apprécier chez l'homme. Les facteurs intervenant dans la régulation mécanique du cartilage sont analysés en fonction des contraintes en compression et en détraction. Les autres facteurs (périoste et muscle) sont rapportés.L'analyse de la littérature montre combien le comportement mécanique et les facteurs régissant la croissance sont mal connus et mériteraient un effort de recherche conjugué pour mieux comprendre la portée des gestes chirurgicaux en orthopédie infantile.

     

Morphometry of terminal hepatic veins

Summary In the present study, hepatic venous distribution per unit of liver surface area on normal wedge biopsies from man (n=11) and baboon (n=8) were analysed and compared. Terminal hepatic veins (THV - man:n=100; baboon:n=200) morphometric size variables were obtained with a Leitz ASM 68K morphometric equipment. THV, defined as hepatic veins up to 150 m in internal diameter (ID), in the centrolobular position and with sinusoidal openings, represented 84% and 74% of hepatic veins of man and baboon, respectively. Four or more THV were generally found on 8 mm² of liver surface. Transversely sectioned THV selected by the ratio IDminimum/IDmaximum >0.67, was found to be only 25% of the total THV. In baboon, THV merge with other terminal veins and the interlobular veins present sinusoidal inlets. The baboon THV wall surface (WS) and wall thickness (WT) values were higher than in man. Positive correlations between the number of mesenchymal cells (Mc) in the vein wall and wall surface of terminal hepatic veins (man: r= 0.79; baboon: r=0.83) and between wall surface and internal surface (IS) (man: r=0.80; baboon: r=0.72) were found. Two ratios were selected as the most reliable parameters: (1) for the THV wall rim, wall surface/internal surface (WS/IS - man: 0.43±0.16; baboon: 0.63±0.23), regarding transversely sectioned THV; and (2) for the evaluation of wall cell density (WS/Mc-man: 550±231; baboon: 558±183 m²/cell) as they did not depend on THV caliber.Dr. Porto was supported by a fellowship from MEC-CAPES, Brazil. A grant for morphometric equipment was obtained from the Fondation pour la Recherche Médicale and from the Societé d'Hépatologie Expérimentale, 77 rue Pasteur, Lyon, France     

Ly49 gene expression in different inbred mouse strains

Mouse natural killer cells express receptors for class IMHC in the form of the Ly49 family of proteins. The Ly49 family contains at least 13 expressed members (A, B, C, D, E, F, G, H, I, J, L, O, and P) and is further subdivided into activating and inhibitory subfamilies based on intracellular and transmembrane characteristics. The level of sequence identity between different members varies dramatically. However, comparison of the extracellular domain has revealed that several of the Ly49 molecules also form “pairs,” where one member is activating and the other is inhibitory. Until recently, most Ly49 molecules described have come from the C57B1/6 strain of inbred mice. Using molecular cloning and immunochemical analysis we have found that different mouse strains express novel Ly49 molecules. Comparison of the allelic forms of some Ly49 molecules has shown that the dividing line between different genes and different alleles is blurred. This project has been funded in whole or in part with federal funds from the National Cancer Institute, National Institutes of Health, under Contract No. NO1-CO-56000. Animal care was provided in accordance with the procedures outlined in A Guide for the Care and Use of Laboratory Animals (National Institutes of Health Publication No. 86-23, 1985). The content of this publication does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. government.     

Hepatic arterial variations and liver-related diseases of 100 consecutive donors

We prospectively studied anatomical variations and diseases of the liver in 100 consecutive donor operations during a period of 1 year. The normal arterial anatomy with a single hepatic artery (HA) from the celiac trunk was seen in 76% of all cases. Seven of twelve different major variations of the HA may be considered as rare, one of which cannot be found in the earlier literature. During harvesting, 6% of the livers were discarded, 3% on the basis of infection and 1% because of a polycystic disease. Two cases were rejected as the liver was found to be severely hypoperfused or hypoxic in an otherwise stable donor. Severe steatosis was macroscopically and histologically diagnosed in 3% of the cases, and in three donors a benign tumour was found in the liver or in the gall bladder. Two primarily nonfunctioning livers in the present series of 94 recipient operations were retrieved from this group of severely steatotic livers. As the donor liver was totally normal in only 2 out of 3 of the cases, the present study underlines the importance of searching for extremely variable anomalies of the HA and for liver-related diseases during organ harvesting.     

Progressive tubulointerstitial nephritis and chronic cholestatic liver disease

We report the clinical and morphological features of a distinctive hepatorenal disorder in four patients and review the five similar patients in the literature. The main clinical characteristics were early onset of cholestatic liver disease and progressive tubulointerstitial nephritis leading to renal death in early childhood. Liver histology showed disturbed architecture with nodular and acinar formations and portal fibrosis and bile duct proliferation. Histological abnormalities in the kidney were severe interstitial fibrosis and tubular atrophy and dilatation, while the typical features of nephronophthisis were lacking. These clinical and morphological characteristics distinguish our patients from the majority described, as having nephronophthisis and congenital hepatic fibrosis or any other known syndrome with concomitant hepatorenel involvement. We suggest that the association of cholestatic liver disease and progressive tubulointerstitial nephritis represents a new syndrome.     

Hepatic Steatosis and Morbid Obesity

One hundred and twenty-seven consecutive morbidly obese patients who presented for bariatric surgery underwent open wedge liver biopsy at the completion of their gastric restrictive procedure. All hepatic specimens were graded histologically for degrees of steatosis. Three-quarters of the patients had histological evidence of hepatic steatosis and in one-fifth this was severe and diffuse. No patient had histological evidence of fatty hepatitis, portal fibrosis, or cirrhosis. There was no significant correlation between the degree of obesity (measured as percentage over ideal weight), age, sex, or preoperative liver function tests and the degree of fatty change observed. Insufficient data were available to implicate alcohol and poor protein nutrition in the aetiology of the observed fatty liver change. Other factors such as diabetes mellitus or drugs were not aetiological factors in this series of patients.     

重组人钙调素对白芷细胞增殖及结核杆菌生长的影响

目的 :探讨重组人钙调素 ( rh Ca M)对白芷悬浮细胞及结核杆菌增殖作用的影响。　方法 :用基因重组技术获得人钙调素基因 ( h Ca M c DNA)重组表达质粒 h Ca M / p BV2 2 0 ,将其转化大肠杆菌 DH5α。用 Phenyl-Sepharose CL -4 B疏水亲和层析法纯化重组菌超声上清表达产物。将纯化 rh Ca M加入悬浮培养的白芷细胞及结核杆菌培养基中 ,观察 rh Ca M对其增殖作用的影响。　结果 :含 h Ca M / p BV2 2 0的重组菌经温度诱导可高效表达Ca M蛋白 ,经 15 % SDS-PAGE分析 ,可观察到一相对分子质量为 170 0 0的表达条带 ,Western blot结果证实 ,此表达条带可与标准鼠抗 Ca M Mc Ab起特异反应。每 1L菌液经 Phenyl-Sepharose CL -4 B疏水亲和层析法纯化可获Ca M纯品 3～ 4mg。rh Ca M对白芷细胞增殖作用影响的研究结果表明 ,rh Ca M在低细胞密度培养条件下对白芷细胞有促进增殖作用 ,效果高于标准植物 Ca M。本研究同时还发现一定浓度的纯化 rh Ca M( 1、10μg/ ml)可促进牛型结核杆菌的生长。　结论 :rh Ca M对植物细胞和细菌均有细胞外促增殖作用     

三磷酸腺苷生物荧光液闪测定法检测活细胞计数

为建立一种检测活细胞数的方法,作者采用三磷酸腺苷(ATP)生物荧光液闪测定法检测小鼠纤维瘤细胞株L929.ATP标准曲线工作范围为10 -9～10-5mol/ml,相关系数r=0.9963(P＜0.001);当活细胞数在3×1 02～106个/ml时与发光计数值有良好的线性关系,r=0.9922(P＜0.001),变异系数 CV = 1%～3%.用ATP生物荧光液闪测定法检测活细胞数灵敏、简便、准确、重复性好,用液闪计数仪即可完成测定,有较大的实用价值.     

P^27的研究概况

目的：综述Ｐ＾２７的研究进展。方法：光盘检索有关献,归纳综合整理。结果：Ｐ＾２７是细胞周期的相关蛋白,Ｐ＾２７白过度表达可抑制细胞周期的进程,阻断细胞生长于Ｇ１期。结论：Ｐ＾２７是细胞周期中重要的负性调控控因子,是一种新的侯选的肿瘤抑制基因。