Reciprocity between membranous and nuclear expression of beta-catenin in colorectal tumours

beta-Catenin has a central role not only in linking the cadherin-mediated cell adhesion system but also in the intercellular signalling pathway. To investigate alterations of beta-catenin in the development of colorectal carcinoma, the pattern of beta-catenin expression was studied using immunohistochemistry in 74 sporadic colorectal adenomas, in histologically normal mucosa adjacent to 65 of these adenomas, and in 52 carcinomas arising in adenomas. All normal epithelia displayed cell boundary staining for beta-catenin. Adenomas and carcinomas showed varying degrees of membranous staining. However, some tumours also showed nuclear staining of beta-catenin protein. Decreased membranous and increased nuclear beta-catenin staining were associated with increasing degrees of dysplasia in adenomas (P < 0.005, P < 0.05, respectively). Carcinomas manifested significantly reduced membranous, but enhanced nuclear beta-catenin expression compared with their associated adenomas (P < 0.001, P < 0.005, respectively). An inverse correlation was found between decreased membranous and increased nuclear staining of beta-catenin in both adenomas and carcinomas (P < 0.025, P < 0.05, respectively). The data confirm that reduced membranous and increased nuclear expression of beta-catenin is associated with the progression of colorectal adenomas to carcinomas. Our results also suggest that decreased membranous expression of beta-catenin may result from aberrant localisation of the protein in the cell nucleus.

[Experimental study and clinical application of arterialized venous skin flap]

In order to investigate the survival mechanism and the role of venous drainage in arterialized venous skin flap, 60 rabbits' ears were used for research and clinical application of the flap was performed subsequently in two cases. The rabbits were divided into 4 groups. Experimental group was standard arterialized venous skin flap, control 1 group was venous skin flap, control 2 group was arterialized venous skin flap with only one drainage vein and control 3 group was normal skin flap. The process of survival of the flaps was observed by hemodynamic and histological method. The results showed that there was no significant difference between standard arterialized venous skin flap and normal skin flap (P > 0.01). Two cases of arterialized venous skin flap survived completely. The conclusion were as follow: 1. the opening of collateral circulation between the veinlets was the main change of the microcirculation; 2. the blood flow of the graft was changed from unphysiological circulation to physiological circulation as the time elapsed and 3. amelioration of venous drainage was important in inproving the survival rate of arterialized vein graft.

Reduced expression of molecules of the cadherin/catenin complex in the transition from colorectal adenoma to carcinoma

E-cadherin is crucial to the intercellular adherens junctions which are involved in the organisation and maintenance of epithelial structure and suppression of tumour invasion. E-cadherin is associated with the actin cytoskeleton via cytoplasmic proteins, including alpha-, beta- and gamma-catenins, which together form the cadherin/catenin complex. To evaluate changes of the molecules of the cadherin/catenin complex in colorectal carcinogenesis, seventy-four sporadic adenomas, samples of histologically normal epithelium adjacent to 65 adenomas, and 52 carcinomas arising in adenomas were investigated by immunohistochemistry. All normal epithelial cells showed a uniform membranous staining pattern for E-cadherin, alpha-, beta-, and gamma-catenin. Decreased expression of all 4 proteins occurred in parallel in adenomas and carcinomas (in all cases, p < 10(-5). Decreased expression of the cadherin/catenin complex in adenomas was associated with increasing severity of dysplasia (p < 0.001, for E-cadherin, alpha-, and gamma-catenin, p < 0.005 for beta-catenin). Carcinomas displayed significantly reduced expression of the cadherin/catenin complex compared with their associated adenomas (all p < 0.001). The results directly confirm that colorectal tumour progression and invasion is associated with disruption of the cadherin/catenin complex and suggest that the genetic changes and transcriptional modulation of catenins underlying this progression may affect all members of the complex.

[Expression of apoptosis regulating proteins P 53, c-myc and bcl-2 on CD34+ hematopoietic cells isolated from human bone marrow]

OBJECTIVE

To show the coexpression levels of P 53, c-myc or bcl-2, three key apoptosis-regulating proteins on CD34+HC and bone marrow mononuclear cells (BMMNC).

METHODS

IsolexTM50 or CIMS-100 systems of immunomagnetic bead separation and two-dimensional flow cytometric analysis of the immunofluorescence double staining were used.

RESULTS

With 90%-95% purity of CD34+HC measured by FACS, we found that expression levels of P53, c-myc, and bcl-2 on both CD34+HC and BMMNC were as follows: CD34+/P53 + 0.1-00.8% versus BMMNC 0.1-0.6%; CD34+/c-myc+2.4%-11. 3% versus BMMNC 0.1-0.4%; CD34+/bcl-2+0.5-1.6% versus BMMNC 0.1-0.8%. Coexpression of c-myc and bcl-2 on CD34+HC was significantly higher than those observed on BMMNC respectively.

CONCLUSION

It could be speculated that apoptosis-regulating proteins P53, c-myc and bcl-2 play a key role in the control of the survival, proliferation, differentiation, maturation and death in hematopoietic cells of physiological state, suggesting that these proteins balance the production numbers and quality of hematopoietic cells.

Searching for information on the Internet using the UMLS and Medical World Search

Medical World Search is a search engine for medical information on the Internet that distinguishes itself from other search engines by its built-in knowledge of medical terminology through its use of the National Library of Medicine's UMLS and its carefully selected but large database of medical sites. After discussing some of the previous uses of the UMLS for medical information retrieval, we describe the Medical World Search system. In October 1996, Medical World Search became operational on the World Wide Web at http:@www.mwsearch.poly.edu. It has been operating uninterrupted since then. We review our experiences with creating a search engine for medical information on the Internet and using the UMLS in this application. The UMLS has some clear advantages in this application. Some aspects of the UMLS also decrease its usefulness in information retrieval. Medical World Search's usage by medical information seekers is summarized. future directions for research are outlined.

[Antiproliferative effects on Ph+ leukemic cells transfected with antisense bcr/abl fusion gene]

To investigate the possible roles that bcr/abl fusion gene plays in Ph-chromosome positive leukemia cells, in this study the recombinant plasmids expressing antisense transcripts to bcr/abl fusion gene were transfected into K562 and BV173 cell lines by lipofectin reagent. Southern and Northern bilot hybridizations proved the integration and expression of exogenous DNA in target cells. Antisense transcripts to bcr/abl inhibited proliferation and colony-forming ability of target cells. Through flow cytometric cell cycle analysis it was found that during the early period of transfection decrease of cells in G0/G1 and S phases and increase in G2 phase were observed, suggesting block of G2 progression. Later, cells in G0/G1 phase decreased further and retardation of S and G2 progressions was obvious. The results also indicated that proliferative inhibition of target cells was accompanied by genomic DNA degradation.

Characteristics of the inward-rectifying potassium current in mouse ventricular myocytes and its relation to early after-depolarization

The properties of the inward-rectifying potassium current (IK1) were studied in the single myocytes isolated from adult mouse ventricles by the whole-cell patch-clamp technique for the first time. Most of the properties of IK1 including channel conductances, activation, inactivation, rectification and external K+ sensitivity in mouse ventricular myocyte were similar to those in other species, but the current-voltage (I-V) curve of mouse ventricular myocyte showed no negative slope, i.e the slope in the range of membrane potential 50 mV positive to the reversal potential (VRev) was virtually flat and remained at a low current level ((59 +/- 39) pA). Under the superfusion of Tyrode's solution with 3 mmol/L K+ and 3 mmol/L Cs+, IK1 in the above region nearly decreased to zero, and then the early after-depolarization (EAD) occurred. The results suggest that this distinctive characteristic of IK1 in mouse ventricular myocyte may relate to the high susceptibility to EAD in mouse myocardium. The inhibition of IK1 seems to be a prerequisite for the occurrence of EAD in this experiment.

[Clinical application of thoraco-umbilical skin flap]

Since 1987 we have successfully used thoraco-umbilical skin flaps as free transplants to repair 8 cases of severe burn scar deformities of jaw-neck and hand regions, thoraco-umbilical insular skin flaps to each case of congenital vaginal atresia, severe vulval scar due to sulfuric acid burn and large penal tissue defect accompanied with severe urethral leakage. This flap has the following advantages: namely definite anatomical position, larger vascular diameter, fight large skin flap area, and similar skin completion as that of the jaw-neck region. Therefore they are the ideal substitute for the repair of soft tissue defects of jaw-neck region as well as extremities. The flap has long vascular pedicle, abundant vascularization, easy transportation and it is suitable to be a retrograde insular flap for repairing of vulval tissue defect, reformed penal vaginoplasty.