Stimulation of DNA repair synthesis of rat thymocytes by novobiocin and nalidixic acid in vitro without detectable DNA damage

Scheduled (SDS) and unscheduled (UDS) DNA synthesis as well as nucleoid sedimentation was investigated in vitro under the influence of novobiocin (NB) and nalidixic acid (NA) using intact thymic (T-cells) and splenic (S-cells) rat cells and cells which were exposed to X-rays, UV irradiation, methyl methanesulfonate (MMS), and DNA polymerase inhibitors. At concentrations of 56.25 (S-cells) and 225 g/ml (T-cells), respectively, NB inhibited SDS in a dose-dependent manner. Within a concentration range of 225–900 g NB/ml, UDS of S-cells decreased to values far below the tracer ([³H-methyl]-thymidine) incorporation of control cells, whereas UDS of T-cells increased by at least 200%. Within a concentration range of 450–1800 g/ml, NA enhanced SDS and UDS by about 30% in S-cells and by 100% in T-cells. The stimulating activity of NB and/or NA could be eliminated specifically by the DNA polymerase inhibitor 2',3'-dideoxythymidine. Enhanced nucleoid sedimentation was observed at NB concentrations 750 g/ml; S-cells revealed a higher sedimentation rate than T-cells. It is suggested that NB (and NA) influence DNA topology in a rather cell specific manner, stimulating UDS of T-cells by a DNA polymerase — dependent repair-like mechanism.     

Scanning electron microscopy of microarterial anastomoses with the argon laser

A carotid end-to-end anastomosis was performed in 50 Wistar rats (mean weight 260 g) by means of a Coherent 900 argon laser. Laser pulses (average 19) of 300 mW power and 5 s exposure time were used, the beam being focused to form a spot of 150 m diameter. From day 0 to day 210, 13 specimens underwent scanning electron microscope examination. The results show that the laser impact produces a wall injury of 100 m in width with some coagulative necrosis of the media and adventitia. The line of anastomosis became re-endothelialized within four days, at which time collagen fusion was observed in the subendothelial layers. The longitudinal arrangement of the endothelial cells was restored by day 10. In the long term, a thick collagenous meshwork maintained the strength of the media, while normal endothelium covered the anastomosis. Complications such as disruption and aneurysm formation were attributed to technical problems.

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Résumé Anastomoses micro-artérielles au laser argon: étude en microscopie électronique à balayage. Les auteurs réalisent au laser Argon (Coherent 900) une anastomose carotidienne terminoterminale sur une série de 50 rats Wistar de poids moyen de 260 g. Les impacts laser (en moyenne 19) sont de 300 mW de puissance et d'une durée de 5 s chacun, avec un point de focalisation de 150 m de diamètre. On réalise sur 13 spécimens un examen en microscopie électronique à balayage. L'impact laser induit sur la paroi artérielle une lésion de 100 m de large avec une légère nécrose de coagulation de la media et de l'adventice. La ligne de suture est re-endothélialisée dès le quatrième jour, alors qu'une fusion du collagène est observée dans les couches sousendothéliales. L'arrangement longitudinal des cellules endothéliales est retrouvé dés le dixième jour. A long terme, un réseau collagénique serré assure la résistance de la media et un endothélium normal recouvre la ligne de soudure. Les complications tel que lâchage ou anéurysmes doivent être attribuées aux inconvénients techniques du début de l'expérimentation.

     

THE ESTABLISHMENT OF THE NORMAL HUMAN FIBROBLAST CELL LINE AND A STUDY OF ITS BIOLOGICAL CHARACTERIZATION

用正常成人包皮组织建立NHF8细胞系在体外长期传代培养达400余天。细胞形态为成纤维样并呈规则的放射状生长。细胞培养于含有15％小牛血清的Ⅰ号培养液中并以1:2比例传代培养。细胞系的群体倍增肘间为26小时,其生长曲线呈“S”形。该细胞系染色体众数为46,自发姐妹染色单体交换率(SCE)为0.144/每染色体,紫外线(UV)诱发SCE率为0.143/每染色体。该细胞系经UV诱发的非合成期DNA修复合成(UDS)水平也是正常的。上述结果表明,NHF8细胞是具有正常DNA损伤修复功能的人二倍体细胞系,可以用于许多研究中作为正常对照细胞。此外,我们还利用该细胞系进行了体外细胞恶性转化及环境诱变物质检测等方面的工作。     

Macromolecular DNA-damage in murine and human leukemic and lymphoid cells after in vitro exposure to ASTA Z 7557 (INN mafosfamide)

Summary Cyclophosphamide (CPA) is widely used against leukemic and lymphoproliferative diseases, but in vitro studies on response to this agent so far have been limited to instable derivatives with poor galenic properties. ASTA Z 7557 is a newly synthesized activated cyclophosphamide that circumvents the need for hepatic activation and has good stability. The critical cytotoxic lesions after exposure to bifunctional alkylating agents presumably are DNA interstrand crosslinks (ISC). We have, therefore, examined the formation and apparent removal of ISC after in vitro treatment with ASTA Z 7557 by use of the highly sensitive alkaline elution technique. Survival of murine L1210 cells was determined after 1 hour in vitro exposure with a D 37 value of 5.7 g/ml (from the initial shoulder part of the survival curve) and a Do value of 1.5 g/ml (from the exponential part of the curve). Previous labelling of L1210 cells by ¹²⁵IUdR simplified the alkaline elution procedure but there was some cytotoxicity of the radiochemical itself with a reduction of cloning efficiency from 77% to 61 %. The maximum of ISC was observed at 6 h after initiation of treatment with much of the damage apparently removed at 24 h. The simultaneous presence of DNA single strand breaks (SSB), however, confounds the analysis of DNA damage at 24 h and early cytolysis and unaided death of human lymphocytes often preclude the analysis of macromolecular damage at this time. Human peripheral blood cells isolated from patients with leukemic or lymphoproliferative diseases showed a remarkable heterogeneity with regard to the formation of ISC at 3 h. Thus, analysis of macromolecular damage may become an additional prognostic factor for response to CPA beyond the morphologic classification of these diseases.     

The fat nose

The fat or sebaceous nose,^* with its thick, bulky skin filled with prominent sebaceous glands, is often improved surgically only by the use of external excisions of this tissue. The author describes several variations of this technique with representative cases.     

Bovine Colostrum: Its Constituents and Uses

Colostrum is the milk produced during the first few days after birth and contains high levels of immunoglobulins, antimicrobial peptides, and growth factors. Colostrum is important for supporting the growth, development, and immunologic defence of neonates. Colostrum is naturally packaged in a combination that helps prevent its destruction and maintain bioactivity until it reaches more distal gut regions and enables synergistic responses between protective and reparative agents present within it. Bovine colostrum been used for hundreds of years as a traditional or complementary therapy for a wide variety of ailments and in veterinary practice. Partly due to concerns about the side effects of standard Western medicines, there is interest in the use of natural-based products of which colostrum is a prime example. Numerous preclinical and clinical studies have demonstrated therapeutic benefits of bovine colostrum for a wide range of indications, including maintenance of wellbeing, treatment of medical conditions and for animal husbandry. Articles within this Special Issue of Nutrients cover the effects and use bovine colostrum and in this introductory article, we describe the main constituents, quality control and an overview of the use of bovine colostrum in health and disease.     

Effects of Bovine Colostrum with or without Egg on In Vitro Bacterial-Induced Intestinal Damage with Relevance for SIBO and Infectious Diarrhea

Small intestinal bacterial overgrowth (SIBO) occurs commonly, is difficult to treat, and frequently recurs. Bovine colostrum (BC) and chicken eggs contain immunoglobulins and other components that possess antimicrobial, immunoregulatory, and growth factor activities; however, it is not known if they have the ability to reduce injury caused by the presence of bacteria associated with SIBO (Streptococcus, Escherichia coli, Staphylococcus, Bacteroides, Klebsiella, Enterococcus, and Proteus) and infectious diarrhea (enteropathogenic Escherichia coli, Salmonella). We examined the effects of BC, egg, or the combination, on bacterial growth and bacteria-induced changes in transepithelial electrical resistance (TEER) and bacterial translocation across confluent Caco-2 monolayers. BC, egg, or the combination did not affect bacterial growth. Adding bacteria to monolayers reduced TEER and (with minor variations among species) increased bacterial translocation, increased monolayer apoptosis (increased caspase-3 and Baxα, reduced Bcl2), increased intercellular adhesion molecule 1 (ICAM-1), and reduced cell adhesion molecules zonulin1 (ZO1) and claudin-1. BC, egg, or the combination reduced these effects (all p < 0.01) and caused additional increases in vascular endothelial growth factor (VEGF) and Heat Shock Protein 70 (Hsp70) expression. We conclude that BC ± egg strengthens mucosal integrity against a battery of bacteria relevant for SIBO and for infectious diarrhea. Oral BC ± egg may have clinical value for these conditions, especially SIBO where eradication of precipitating organisms may be difficult to achieve.     

自体骨膜游离移植修复关节软骨缺损进展

探讨自体骨膜游离移植修复关节软骨缺损的研究进展。从骨膜的解剖生理功能和骨膜再生软骨能力两方面进行分析,并阐述了关节内营养环境、关节活动、骨膜生发层不同朝向、年龄及手术技巧等因素对移植修复的影响。同时总结了该方法的临床应用状况、效果及存在的问题。实验及临床的研究证明自体骨膜游离移植是修复关节软骨缺损的重要手段,局部环境因素影响骨膜成软骨。     

一针法修补上消化道穿孔

目的 探讨上消化道穿孔修补方法的改进及疗效。方法 将5年内收治的286例上消化道穿孔病人分成A、B两组,A组行带血管蒂大网膜束填塞一针修补,大网膜束缝合覆盖;B组采用传统术式。结果 A组146例病人平均手术时间38分钟,平均住院天数8天,术后随访一年,无1例幽门狭窄或梗阻发生。B组140例病人平均手术时间52分钟,平均住院天数10天,术后随访一年,经钡餐及胃镜检查证实为术后疤痕性幽门管狭窄26例。结论 两组比较带血管蒂大网膜束填塞一针修补上消化道穿孔明显优于传统的多针修补。     

倍骼生在颌骨小范围缺损修复中的应用

目的：观察倍骼生（Perioglas)在颌骨小范围缺损修复治疗中的应用效果。方法：对34例牙源性颌骨囊肿手术后缺损（直径≤30mm)和40例因 牙槽骨高度或厚度不足需行种植修复的病例应用倍骼生植入修复缺损,术后拍片检查并测量植入物高度的变化,观察其密度的变化。结果：倍骼生植入初期高度逐渐变低,密度逐渐降低,但4周以后高度不再减低,密度开始回升。8周以后渐趋近正常骨组织密度。 结论：倍骼生在骨缺损区植入时有骨引导和骨诱导的作用,对缺损区早期形成有功能性的、成熟的骨组织有促进作用。