p53 gene mutations and their expression in protein levels of colorectal adenomas, carcinomas and regional lymph nodes metastasis were detected by PCR-SSCP and AB-PAP immunohistochemical analysis, respectively. The results showed that p53 gene mutations were detected in 25% colorectal adenomas, 80% carcinomas and 100% regional lymph nodes metastasis. Meanwhile, p53 proteins were detected at rates of 75%, 60% and 57% in these three groups, respectively. It is suggested that p53 gene mutations occur frequently at late stage of progression to colorectal adenoma-carcinoma sequence and may relate to its metastasis, while the accumulation of p53 protein may be a specific genetic alteration initiated from adenomatous stage. Thus, the biological significances of the two genetic alterations are different. Investigations of these concomitantly would be helpful in understanding the malignant potential of adenoma and evaluation of its staging.

OBJECTIVETo inquire about the relationship of p53 gene mutation to the histopathological findings and clinical manifestation in cases of laryngeal squamous cell carcinoma(LSCC).

METHODSThe fresh samples from 60 cases of LSCC were examined. Polymerase chain reaction and silver staining-single strand conformation polymorphism (PCR-SSCP) and DNA direct sequencing were used to detect the mutation of p53 gene in exons 5-8.

RESULTSThe mutation rates were 69.2% and 85.3% in patients at clinical stage I-II and stage III-IV respectively (P>0.05). In the well-, moderately- and poorly-differentiated cell of LSCC, the mutation rates were 52.9%, 83.3% and 94.7% respectively (P<0.05). The p53 gene mutation rate of LSCC patients with neck lymph-node metastasis was 96.4%, whereas that of patients without neck lymph-node metastasis was 62.5% (P<0.05). Twenty samples showed positive results in SSCP; 19 samples showed deletion and mutation in codons 125-292 by DNA direct sequencing.

CONCLUSIONThe mutation of p53 gene in exons 5-8 was closely related to cell differentiation and the neck lymph-node metastasis of LSCC, but it was not related to the clinical stages of the LSCC cases.

Carcinoma, Squamous Cell ; genetics ; secondary ; Cell Differentiation ; genetics ; Exons ; Humans ; Laryngeal Neoplasms ; genetics ; pathology ; Lymphatic Metastasis ; genetics ; Mutation ; Neoplasm Staging ; Polymerase Chain Reaction ; methods ; Polymorphism, Single-Stranded Conformational ; Sequence Analysis, DNA ; methods ; Tumor Suppressor Protein p53 ; genetics

OBJECTIVETo investigate the effects of three-dimensional parallel collagen scaffold on the cell shape, arrangement and extracellular matrix formation of tendon stem cells.

METHODSParallel collagen scaffold was fabricated by unidirectional freezing technique, while random collagen scaffold was fabricated by freeze-drying technique. The effects of two scaffolds on cell shape and extracellular matrix formation were investigated in vitro by seeding tendon stem/progenitor cells and in vivo by ectopic implantation.

RESULTSParallel and random collagen scaffolds were produced successfully. Parallel collagen scaffold was more akin to tendon than random collagen scaffold. Tendon stem/progenitor cells were spindle-shaped and unified orientated in parallel collagen scaffold, while cells on random collagen scaffold had disorder orientation. Two weeks after ectopic implantation, cells had nearly the same orientation with the collagen substance. In parallel collagen scaffold, cells had parallel arrangement, and more spindly cells were observed. By contrast, cells in random collagen scaffold were disorder.

CONCLUSIONParallel collagen scaffold can induce cells to be in spindly and parallel arrangement, and promote parallel extracellular matrix formation; while random collagen scaffold can induce cells in random arrangement. The results indicate that parallel collagen scaffold is an ideal structure to promote tendon repairing.

Collagen ; chemistry ; Extracellular Matrix ; physiology ; Freeze Drying ; Freezing ; Humans ; Stem Cells ; cytology ; Tendons ; cytology ; growth & development ; Tissue Engineering ; Tissue Scaffolds ; chemistry