Large enchondroma of the thoracic spine: a rare case report and review of the literature.

BACKGROUND: Enchondroma, a subtype of chondroma, originates from the medullary cavity of the bone and produces an expansile growth pattern. Enchondroma located in the spine is rare and a few cases of large thoracic enchondroma have been reported. The authors document a rare case of large enchondroma in the thoracic spine of a 49-year-old woman, and discuss its clinical, radiological and histopathological characteristics. CASE PRESENTATION: The patient presented with rapidly progressive and severe pain on her upper back. Magnetic resonance imaging revealed an expansile lesion at the posterior elements of T3 that was hypointense on T1-weighted images and mixed iso- to hyperintense on T2-weighted images. Administration of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) resulted in heterogeneous enhancement. During surgery, a large tumor of 4.2cm × 4.7cm × 2.1cm was resected along with the lamina and spinous process. Histological examination revealed that the tumor consisted of mature hyaline cartilage with typical chondrocytes, indicating that it was an enchondroma. CONCLUSIONS: Despite its benign-growing nature, enchondroma should be examined closely for signs of enchondromatosis and enchondrosarcoma. Complete surgical resection is the treatment of choice for immediate relief of symptoms and avoidance of recurrence.

[Photosynthetic characteristics of Emmenopterys henryi seedlings and their relationships with environmental factors]. / é¦™æžœæ ‘å®žç”Ÿè‹—çš„å ‰åˆç‰¹æ€§åŠå ¶ä¸ŽçŽ¯å¢ƒå› å­çš„å ³ç³».

To find appropriate environment for Emmenopterys henryi seedlings and develop corresponding strategies for their natural regeneration, the net photosynthetic rate, water use efficiency, chlorophyll content, height, basal diameter and biomass of two-year old seedlings and the relationships with environmental factors were studied in different habitats, i.e., undercanopy, crown edge, forest gap, and forest edge. In the four habitats, the maximum photosynthetically active radiation (PAR) was 50-1380 Μmol·m-2·s-1, net photosynthetic rate of E. henryi seedlings showed singlet diurnal variation in undercanopy and crown edge, and showed a bimodal pattern in forest gap and forest edge. Seedlings were shade-tolerant plants with the low shade-tolerant ability. The order of light saturation point, light compensation point, and dark respiration of their functional leaves in different habitats was the same as follows: forest edge ＞ forest gap ＞ crown edge ＞ undercanopy, and the order was inverse when sequenced by apparent quantum efficiency. Seedlings were highly adaptable to forest gap and crown edge, with higher transpiration rate, stomatal conductance, water use efficiency (WUE), and net photosynthetic rate. Seedlings in forest gap had lower leaf chlorophyll content, but they grew fast and therefore showed the maximum biomass. Net photosynthetic rate of the seedlings showed significant positive correlation with PAR and stomatal conductance. For undercanopy, seedling photosynthesis was facilitated by reducing canopy density and increasing light transmittance. For forest edge, vegetation cover should be increased with reducing light intensity to ensure rapid growth of the seedlings.

[Species diversity and interspecific association in development sequence of Hippophae rhamnoides plantations in Loess hilly region].

Based on field investigation, this paper analyzed the characteristics of species diversity and interspecific association at different development stages of Hippophcze rhamnoides plantations. The results showed that the species diversities of shrub layer, grass layer, and whole community of H. rharnnoides plantations were all fluctuated in "S" shape. At different development stages, the species richness and diversity were higher in grass layer than in shruh layer. The shrub species diversity was lower on hare land, but increased gradually with development stage. Shrub evenness index was higher in 13-year forest stand, while grass diversity index was higher in 3-year plantation, lower in 8-year plantation, and higher in 25-year plantation. The positive and negative absolute values of interspecific association between H. rharnnoides and other principal species changed in parabola shape, and the notable degree and the interspecific association intensity were weaker in 13-year plantation, showing that the species substitution rate was slower, competition was less, and community composition and its structure were relatively stable. To improve ecological environment, the H. rhamnoides plantations younger than 13 years old should he given priority to protection, while for those of 25 years old, moderate thinning should be made to promote the regeneration.