Development of the blood-testis barrier in the domestic fowl (Gallus domesticus)

The formation of the blood-testis barrier (BTB) in the domestic fowl was studied at the electronmicroscopic level employing lanthanum as a tracer. No effective barrier could be demonstrated in testes before puberty, although several components of the Sertoli junctional complex such as focal tight junctions and desmosomes were already existent. The time of onset of meiosis after hatching showed great individual variation and meiosis did not occur synchronously in the tubules of a given testis. An effective barrier could first be detected in tubules containing early spermatids, and in which spermatogonia and primary spermatocytes at the leptotene stage were still within the open compartment. Thus, barrier formation was correlated with the occurrence of haploid germ cells. Complete compartmentation of seminiferous tubules, leaving only spermatogonia within the open compartment, was attained in tubules containing elongated spermatids of the maturation phase. In these tubules, primary spermatocytes at the leptotene stage were situated in an intermediate compartment.     

Growth cones and axon trajectories of a sensory pathway in the amphibian spinal cord

Central axons of sensory ganglion (SG) neurons of the Xenopus tail enter the spinal cord via the ventral roots and travel dorsally and rostrally following a diagonal course within the lateral marginal zone (LMZ) to reach the dorsolateral fasciculus (DLF) (Nordlander et al.: Brain Res., 440:391-395, 1988). Axons are dispersed as they cross the cord. At the DLF they turn and travel together rostrally, sharing the fascicle with axons of primary sensory neurons (Rohon-Beard cells) already present in the tract. In this paper we analyze the growth patterns of the central projections of SG axons in the tail by using HRP applied to proximal branches of tail spinal nerves. Growth cones of the diagonal route are variable in configuration, often bearing processes that spread within the LMZ. Once the DLF, growth cones change shape, becoming distinctly linear. While growth cones navigating the diagonal part of the route never contact or fasciculate with other diagonal SG axons, SG growth cones and axons of the DLF are more closely associated with their fellows. Measurements of the slopes of SG axons in the diagonal route indicated a limited range with a mean of 23 degrees with respect to the cord axis. On the basis of these observations, we conclude that 1) navigational patterns for growth cones of this pathway differ for the diagonal versus the DLF part of its course, and 2) fasciculation is not a mechanism used by SG axons to reach the DLF, but that instead, each axon is able to find its way independently.     

复合干细胞生物陶瓷在裸鼠异位成骨中的评价

目的 研究h-BMP-2基因转染骨髓间充质干细胞(BMSCs)在复合煅烧骨、β-TCP或直接植入裸鼠股部后的成骨能力。方法 通过影像学、组织学和形态计量学等方法,观察未经诱导、OS液诱导和h-BMP-2基因转染BMSCs在复合煅烧骨,或多孔β-TCP后植入裸鼠皮下,或直接制成细胞悬液注入,在4、8、12周诱导成骨和材料降解情况。结果 在裸鼠皮下,单纯生物陶瓷不能诱导成骨,而复合了未诱导、OS液诱导和h-BMP-2基因转染BMSCs的生物陶瓷均能成骨,成骨量为h-BMP-2基因转染组>OS液诱导组>未经诱导组(P<0.05),B-TCP可随骨长入而降解;注入裸鼠肌肉的OS液诱导的和h-BMP-2转染的BMSCs均能诱导成骨,而未经诱导MSCs则不能成骨。结论 复合人BMP基因转染BMSCs的β-TCP是一种理想的骨修复材料。     

Distinct osteogenic mechanisms of bones of distinct origins

Mammalian bones have three distinct origins (paraxial mesoderm, lateral plate mesoderm, and neural crest) and undergo two different modes of formation (intra-membranous and endochondral). Bones derived from the paraxial mesoderm and lateral plate mesoderm mainly form through the endochondral process. During this process, hypertrophic chondrocytes play a vital role in inducing both osteogenesis and angiogenesis. One of the essential osteogenic factors secreted from hypertrophic chondrocytes is Indian hedgehog (Ihh). In contrast, bones derived from the neural crest mainly form through the intramembranous pro-cess and do not require Ihh. Thus, depending on their origin, bones have distinct signaling properties, which need to be considered in the research and application of bone biology.Presented at the 18th Annual Research Meeting of the Japanese Orthopaedic Association, Kitakyushu, Japan, October 17, 2003     

胆碱酯酶重活化剂PAM类构型、构象问题

本文参考X-衍射数据,采用MNDO程序计算了不同构型、构象PAM类的生成热,结合核磁共振数据讨论了PAM类构象等问题.结果表明,PAM类在水溶液中:顺式体肟基可以自由旋转,任何一种构象都可能成为药效构象;反式体肟基本不可能存在稳定的平面构象,其药效构象只能是优势构象.用MNDO程序中反应途径的计算法,还计算了顺、反式肟基构型相互转变的势垒,为探讨PAM类重活化机理提供了一定的参考.     

Effect of cortisone on cells at the bone-marrow interface

Summary A study of the association between the rate of proliferation of marrow fibroblast-like stromal cells (in vitro) and the rate of endosteal bone mineralization (EsMR) (in vivo) was undertaken in an osteopenic rat model. We report than 200 g male rats treated with cortisone acetate (5 mg/day for 7 days) exhibit decreases in marrow fibroblast colony-forming units (FCFU) and tetracycline-based measurements of EsMR at the level of the femoral midshaft. In cortisone-treated rats recovering for 1–3 weeks, the FCFU census and EsMR normalized during the first posttreatment week, remained at control levels after 2–3 weeks, and exhibited a relapse in the third week which signified only partial recovery. These changes were unrelated to patterns of body weight gain. The data indicate that the FCFU census can serve to index endosteal osteoblast vigor.     

Reoperation for a patient with starr-edwards aortic valve malfunction due to pannus formation twenty-nine years after implantation

We report a re-do case of severe aortic valve stenosis due to pannus formation 29 years after an aortic Starr-Edwards caged-ball valve implantation. A huge shelf of calcified and thick pannus tissue below the valve had reduced the already small orifice by at least a third in surface area. The explanted Starr-Edwards valve revealed no mechanical or structural failure. Early detection and treatment of pannus outgrowth is essential in order to prevent life-threatening prosthetic valve malfunctions.     

Postnatal formation of the blood-testis barrier in the rat with special reference to the initiation of meiosis

Summary Postnatal formation of the Blood-Testis Barrier (BTB) in the rat was studied by either fixation in hypertonic fixative or employing lanthanum tracer. After 15 days of age, meiosis has reached different stages of spermatogenesis in differnt zones of the seminiferous cords. Only in those parts where germ cells are in the pachytene stage of meiosis do Sertoli cells form an effective barrier or tight compartment. Between 16 and 19 days of age, final formation of the BTB, which is to be found in the adult rat testis, occurs by zygotene and then leptotene stages successively entering the tight compartment. Thus, formation of a BTB by Sertoli cells does not occur synchronously along the length of the seminiferous cord but in accordance with the stage of meiosis of the associated germ cells.     

EVALUATION OF THE LOOPING FORMATION AND PAIN DURING INSERTION INTO THE CECUM IN COLONOSCOPY

Introduction: One of the causes of pain during insertion of the colonoscope is stretching of the mesenterium by loop formation. The degree of pain differs according to the type of loop formation. Our aims were to study the accuracy of the colonoscopist’s assessment of the presence and type of loop formation and to study the degree of pain in relation to the type of loop by administering the visual analog scale (VAS). Methods: Two hundred and fifty‐seven consecutive patients were enrolled. All procedures were performed by two experienced colonoscopists who were blind to magnetic endoscope imaging view. After the colonoscopy, the colonoscopist was asked to assess the presence and type of loop formation. The degree of pain was assessed using the VAS. Results: The accuracy of estimating N loop, alpha loop, absence of loop formation and U loop was each over 70%. The accuracy of estimating gamma and splenic loop was significantly lower than the accuracy of estimating U loop. Colonoscopy was significantly more painful in women than in men. The degree of pain was significantly higher upon formation of reverse alpha loop and gamma and splenic loop than upon formation of N loop and U loop. Conclusions: Upon formation of reverse alpha loop or gamma and splenic loop, patients experienced more pain and it was difficult for the endoscopists to assess these loops. As women had severe pain compared with men, the use of a pediatric colonoscope or higher dosage of sedation in women should be considered.     

Oculomotor nerve palsy due to thrombosis of a posterior communicating artery aneurysm following diagnostic angiography

We present a patient who developed a painful third nerve galsy two days after angiography had demonstrated a large aneurysm on the P1 segment of the left posterior cerebral artery. CT at this stage demonstrated extensive thrombus within the previously uncomplicated aneurysm. The haemodynamics of this aneurysm resulted in incomplete clearance of contrast medium from its fundus and we posit that this may have promoted thrombus formation. Six months later the aneurysm was shown angiographically to be completely occluded.