Bacteriologic status of the root canal after sonic, ultrasonic and hand instrumentation

Abstract The purpose of this study was to assess the bacteriologic status of the root canal after sonic, ultrasonic and hand instrumentation. Root canal infection was induced in 50 single-rooted teeth in young dogs by removing the pulp and filling the canals with dental plaque. After 7 clays the root canals were instrumented under aseptic conditions with conventional hand instruments, a sonic vibratory device or an ultrasonic device. Sterile saline or 2.5% sodium hypochlorite was used as irrigating solution. Following instrumentation a sterile paper point was sealed into the root canals. After 7 d the root canals were reopened under aseptic conditions and the paper points were incubated for the demonstration of bacteria, using pre-reduced thioglycolate culture medium and anaerobic chambers. The results obtained with the different instrumentation techniques and irrigating solutions were compared by means of the Chi-square test. The results indicated that the sonic and ultrasonic devices were not more effective in the elimination of bacteria from the root canal than conventional hand instrumentation. Irrigation with sodium hypochlorite appeared to be more effective than saline in producing bacteria-free root canals; however, this difference was not statistically significant. Thus, it appeared that more than one appointment and the supporting action of an antibacterial medicament between appointments would be necessary to achieve bacteria-free root canals in infected teeth in a predictable manner.     

Mirror image duplication of the hands and feet: Report of a sporadic case with multiple congenital anomalies

Mirror image duplication of the hands and feet is a rare entity. Based on 3 previous reports, findings include nasal abnormalities, dimelia of ulna and fibula, tibial hypoplasia and mirror image duplication of hands and feet. We report on a sporadic case in which mirror image duplication was associated with multiple congenital anomalies. Although these cases may represent variable expression of the same dominantly transmitted complex polysyndactyly syndrome, it is possible that mirror image duplication of the hands and feet is a manifestation common to a number of distinct clinical entities. During limb bud development, duplication and aberrant positioning of the zone of polarizing activity in relation to the apical ectodermal ridge may account for the anatomic abnormalities of the hands and feet in these patients. © 1995 Wiley-Liss, Inc.     

Novel association of multiple gastrointestinal anomalies in a single patient: Can Sonic Hedgehog explain it?

The occurrence of four gastrointestinal (GIT) anomalies in a single patient is extremely rare. Only one report of four GIT anomalies in a child has been published in the English literature. The current report presents a child with four anomalies and discusses the molecular mechanisms which control the development of the gastrointestinal tract.     

Soluble factors from neuronal cultures induce a specific proliferation and resistance to apoptosis of cognate mouse skeletal muscle precursor cells

The mechanisms or the physiological events, which control the regeneration of skeletal muscle through muscle precursor cell multiplication and differentiation, are still largely unknown. To address the question of the involvement of neurons in this process, skeletal muscle progenitors were grown in the presence of conditioned media obtained from 3-day-old cultures of embryonic neurons (derived from either the dorsal or the ventral region of 11-day-old mouse embryos) or media conditioned with satellite cells. Strikingly, only satellite cells cultured in medium conditioned from ventral embryonic neurons exhibited increased proliferation, as well as resistance to staurosporine (STS)-induced apoptosis. Our results suggest the existence of specific anti-apoptogenic neural soluble signals, which could be involved in skeletal muscle regeneration pathways.     

Facilitated sprouting in a peripheral nerve injury

During regeneration of injured peripheral nerves, local conditions may influence how regenerative axon sprouts emerge from parent axons. More extensive lesions might be expected to disrupt such growth. In this work, we discovered instead that long segmental crush injuries facilitate the growth and maturation of substantially more axon sprouts than do classical short crush injuries (20 mm length vs. 2 mm). At identical distances from the proximal site of axon interruption there was a 45% rise in the numbers of neurofilament labeled axons extending through a long segmental crush zone by 1 week. By 2 weeks, there was a 35% greater density of regenerating myelinated axons in long compared with short crush injuries just beyond (5 mm) the proximal injury site. Moreover, despite the larger numbers of axons, their maturity was identical and they were regular, parallel, associated with Schwann cells (SCs) and essentially indistinguishable between the injuries. Backlabeling with Fluorogold indicated that despite these differences, the axons arose from similar numbers of parent motor and sensory neurons. Neither injury was associated with ischemia. Both injuries were associated with rises in GFAP (glial acidic fibrillary protein) and p75 mRNAs, markers of SC plasticity but p75, GFAP and brain-derived neurotrophic factor mRNAs did not differ between the injuries. There was a higher local mRNA level of GAP43/B50 at 7 days following injury and a higher sonic hedgehog protein (Shh) mRNA at 24 h in long crush zones. GAP43/B50 protein and SHH protein both had prominent localization within regenerating axons. Long segmental nerve trunk crush injuries do not impair regeneration but instead generate greater axon plasticity that results in larger numbers of mature myelinated axons. The changes occur without apparent change in SC activation, overall nerve architecture or nerve blood flow. While the mechanism is uncertain, the findings indicate that manipulation of the nerve microenvironment can induce substantial changes in regenerative sprouting.     

Sonic Hedgehog Effectively Improves Oct4-Mediated Reprogramming of Astrocytes into Neural Stem Cells

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Wistar大鼠SONIC HEDGEHOG基因的克隆和表达

为了获得SHH蛋白以研究它在治疗神经变性疾病中的作用，本室提取不同胚龄Wistar胎鼠中的总RNA，应用RT-PCR技术获得SHH-N的cDNA，重组于pGEM-T载体，经测序鉴定后，构建原核表达质粒并获得表达菌株p15．SHH-H，然后诱导SHH蛋白的表达。结果发现，在E11．5-E20．5胎鼠的脊索中能克隆到630bp的cDNA片段，并且随胚龄增加，此片段的表达量逐渐减少；测序结果显示，此片段及其所编码的氨基酸序列同数据库中人、小鼠和SD大鼠的SHH—N的序列有较高同源性；表达菌株经诱导后产生约21kD的融合蛋白。提示SHH-H是一种发育相关基因，在不同种属中的同源性较高，并且在原核系统中能进行表达。