N,N'-Bis(pyridin-3-yl)terephthalamide-terephthalic acid (1/1).

In the title compound, C(18)H(14)N(4)O(2)·C(8)H(6)O(4), both types of mol-ecule lie on inversion centers. In the N,N'-bis-(pyridin-3-yl)terephthalamide mol-ecule, the pyridine ring forms a dihedral angle of 11.33 (9)° with the central benzene ring. In the crystal, N-H⋯O and O-H⋯N hydrogen bonds connect the components into a three-dimensional network.

A novel piezoelectric immunosensor for detection of carcinoembryonic antigen.

A simple, rapid, and highly sensitive immunosensor for the direct determination of carcinoembryonic antigen (CEA) in human serum using a piezoelectric crystal has been developed and optimized. In order to improve sensitivity of the immunosensor, a protein A-based orientation-controlled immobilization method for antibodies was adopted together with an immunoreactive accelerant of polyethyleneglycol (PEG) used to amplify the signal response of frequency. Human normal serum was utilized as a reference background. The linear range for CEA concentration obtained by the end-point method was 66.7-466.7ng/mL. Clinical samples from cancer patients were analyzed by the proposed piezoelectric immunoassay, and the analytical results were reasonably comparable with those obtained by the chemiluminescence immunoassay (CLIA). The proposed immunosensor provides a new promising method for the highly sensitive immunoassay of CEA in clinical laboratory.

[Cell cycle analysis and P53 gene mutation detection of fibroblasts derived from the surrounding skin of keloids].

OBJECTIVE: To investigate whether there are abnormal fibroblasts in the surrounding skin of keloids for better understanding of the etiological feature of keloids. METHODS: Fresh samples were used for cell culture. Flow cytometry was used for analyzing cell cycles of fibroblasts derived from keloids and the surrounding skin. Proliferative cell proportions were compared between every two groups. P53 exon 4, 5 and 6 were amplified by PCR. DNA was sequenced to examine the structure of the destination gene. RESULTS: The proliferative cell proportion of the fibroblasts derived from the surrounding skin is not so high as that from the verge of keloids, but is higher than the normal skin fibroblasts derived from other part of the keloid patients or persons without keloids (P < 0.05). Mutations (point and frameshift mutations) of P53 exon 4 (6/6) and exon 5(2/6) in fibroblasts derived from the surrounding skin of keloids were identified. Fibroblasts derived from keloids have the same mutations as its surrounding skin. CONCLUSION: There are abnormal fibroblasts in the surrounding skin of keloids. It may be the consequence of keloid infiltrative growth and a reason of easy recurrence of keloid after therapy.

[Study on the injurious effect of a self designed micro-skin machine on the epithelia].

OBJECTIVE: To observe the injury on micro-skin induced by a self designed micro-skin machine. METHODS: Micro-skin was produced either with the machine or by hand. Cells at the edge of micro-skin were observed by transmission electron microscope. succinic dehydrogenase activity in supernatant of cultivated cells was analyzed, and the cell proliferation of micro-skin was assessed by (3)H-TdR. Twenty patients were enrolled in the study for the observation of the wound healing time between the two groups of micro-skin after being grafted. RESULTS: Transmission electron microscope examination revealed that the cellular injury at the edge of the micro-skin in machine-made group was mild compared with that in man-made group. (3)H-TdR rate was elevated but the activity of succinic dehydrogenase in the supernatant of cultured cells decreased in supernatant of cultured cells of machine produced micro-skin. Wound healing time was shortened in machine made group. (P < 0.05). CONCLUSION: The cellular injury at the edge of micro-skin in the machine made group was mild when compared with that in the man-made group with cell proliferation accelerated and wound healing time shortened.