Novel 3D collagen scaffolds fabricated by indirect printing technique for tissue engineering.

This article reports the mechanical properties and in vitro evaluation of a collagen scaffold fabricated using an indirect 3D printing technique. Collagen scaffolds, featuring predefined internal channels and capillary networks, were manufactured using phase change printing. It was observed that the collagen scaffolds featured internal channels and a hierarchical structure that varied over length scales of 10-400 microm. In vitro evaluation using hMSCs demonstrated that the resultant collagen based scaffolds have the ability to support hMSC cell attachment and proliferation; cells can migrate and survive deep within the structure of the scaffold. The cell numbers increased 2.4 times over 28 days in culture for the lysine treated scaffolds. The cells were spread along the collagen fibers to form a 3D structure and extracellular matrix was detected on the surface of the scaffolds after 4 weeks in culture. The crosslinking treatment enhanced the biostability and dynamic properties of the collagen scaffolds significantly.

How echographic image analysis of venous oedema reveals the benefits of leg elevation.

OBJECTIVE: Venous insufficiency, leading to venous oedema, is a key pathogenic factor for the non-healing of venous leg ulcers. This study aimed to evaluate the effects of leg elevation on venous oedema. METHOD: Ten patients aged 44-89 years (median: 61) with leg oedema had high-frequency B-mode ultrasound scanning and digital image analysis before and after three to four hours of leg elevation. The echographic image analysis system was used, where oedema is represented by the hypoechogenic part of the image--that is, the total number or density of low echogenic pixels (LEPs) in a particular area. RESULTS: Compared with pre-elevation, the volume of the lower leg decreased by 2.9% +/- 0.6 (138 cm3 +/- 39) after three to four hours' elevation (p < 0.05). After elevation, the LEPs in the upper, middle and lower sites of the limb decreased by 8.8%, 15.6% and 17.3% respectively, reaching statistical significance (p < 0.05) in the lower site. The ratio of LEPs in the upper and lower dermis in the upper, middle and lower sites decreased by 30.3%, 45.8% and 22.5% respectively. This was significant in both the middle and lower sites (p < 0.01). After elevation dermal thickness increased by 0.047 mm, 0.194 mm and 0.232 mm respectively. This change was statistically significant in the middle (p < 0.05) and lower sites of the limb (p < 0.01). CONCLUSION: LEPs are a sensitive marker of dermal oedema and its effects. Leg elevation is extremely effective in reducing oedema, even if only for three to four hours.

[Study on the etiology of herpes viral encephalitis in Changsha area].

OBJECTIVE: To study the relationship between herpes viral infection and viral encephalitis. METHODS: The cerebral spinal fluid(CSF) and sera of the patients with viral encephalitis were detected for herpes virus-specific IgG and IgM with indirect fluorescent antibody assay (IFA). RESULTS: One hundred and thirty-three (14.4%) cases of 921 patients with viral encephalitis were diagnosed as herpes simplex viral encephalitis, of which the maximum morbidity is under the age of 10, 9(0.98%) cases as cytomegaloviral encephalitis and 12 (1.3%) cases as varicella-zoster viral encephalitis. CONCLUSION: Herpes simplex viruses are the common causative agents of viral encephalitis in Changsha area, and IFA is valuable for the diagnosis of herpes viral encephalitis.

[Investigation of the effects of biotic field of plant seedling on human body].

In this paper we investigated the effects on human bodies after being placed in the Jiang's guideti cabin with biotic field to receive the plant seedlings' irradiating biological electromagnetic waves. The results found that the erythrocyte membrane permeability and fragidity were decreased, its tenacity increased, the secretion of thyroid and sexual hormones increased, the immune function enhanced and there was no significant alteration of the adrenal cortical hormone secretion. It is suggested that the electromagnetic wave from the plant seedlings is beneficial to the erythrocyte function, improves the metabolism, enhances the adolescent activities, improves sexual activity and enhances immune function, thus it is effective to health care and rejuvenation.

Macrophages in degradation of collagen/hydroxylapatite(CHA), beta-tricalcium phosphate ceramics (TCP) artificial bone graft. An in vivo study.

The macrophages mediated biodegradation of two biomaterials, collagen/hydroxylapatite (CHA) and beta-tricalcium phosphate ceramics (TCP), was studied in 24 male Kunming mice and 20 male C57BL/6 mice with histopathologic, histochemical and ultrastructural observation. It was demonstrated that macrophages infiltrated after CHA, TCP were implanted. The macrophages could be differentiated from fibroblasts and the other infiltrated cells for special cellular profile and strong acid phosphatase activity. Morphologically, monocyte-macrophages and infused multinuclear giant cell degraded CHA and TCP by phagocytosis and extracellular resorption. The carbonic anhydrase activity of macrophages was demonstrated by histochemical technique. It suggested that macrophages secreted H+ and accomplished the decalcification of calcium phosphate compound of CHA and TCP. We conclude that macrophages are the main mediating cells which degraded CHA and TCP intracellularly and extracellularly.

Macrophages in degradation of calcium phosphate compound artificial bone: an in vitro study.

The isolated mice peritoneal macrophages in degradation of calcium phosphate compound artificial bone--collagen/hydroxylapatite (CHA), hydroxylapatite (HA), beta-tricalcium phosphate (TCP) ceramics, have been studied by use of both Ca++, P concentration assay in cultured supernatant and scanning electron microscopy (SEM). The solubility of Ca++, composition of materials increased more significantly when macrophages were inoculated than when macrophages were not seeded (P < 0.001), and it was shown that the ground materials were wrapped and phagocytized or resorbed extracellularly by macrophages under SEM, suggesting that macrophages could mediate the degradation of calcium phosphate compound artificial bone by phagocytizing and/or degrading extracellularly.

An ultrastructural observation of macrophages in rabbits' radius callus.

The ultrastructure of macrophages in rabbits' radius callus at the 14th and 31st day after fracture had been observed in the study. It was found that macrophages mostly appeared in the early stage callus where there were inflammation, clot, and bone chips. Commonly seen macrophages were active phagocytes with single nucleus, but they could evolve to form multinuclear macrophages or fuse into foreign body giant cells. We are therefore led to conclude that the functions performed by macrophages in healing callus are to phagocytize and digest damaged cellular fragments, small bone chips, clot and foreign body; to disrupt larger dead bone matrix extracellularly and to resorb them by microvilli-like processes on the surface of foreign body giant cells.