Histology and histopathology Vol.16, nº 2 (2001)
Ir a Estadísticas
Permanent URI for this collection
Browse
Recent Submissions
- PublicationOpen AccessCell adhesion molecules in human osteoblasts: structure and function(Murcia : F. Hernández, 2001) Bennett, J.H.; Moffatt, S.; Horton, M.Osteoblasts and bone lining cells form a near continuous layer covering the bone surface and interactions between these cells and the organic matrix of bone are important determinants of osteoblast proliferation and differentiation. In addition, cells of the osteoblast-lineage form functional cornrnunications with each other, with the extra-cellular matrix and with osteocytes through cytoplasmic processes extending through canaliculi in the bone. Together, these cells form a network of putative importance in the regulation of skeletal homeostasis. Cell-cell and cell-matrix interactions are mediated by members of severa1 families of cell adhesion molecules, and knowledge of their interactions will be of fundamental importance in understanding the role of osteoblast in skeletal turnover . Here, the expression pattern of members of the major families of cell adhesion molecules by cells of the osteoblast lineage is reviewed. Special emphasis has been placed on human tissues. In addition, the possibility that cells at progressive stages of the osteoblast lineage have different profiles of cell adhesion molecule expression is explored, and the putative significance of cell-matrix interactions in human skeletal disease briefly discussed.
- PublicationOpen AccessThe localization of thrombospondin-1 (TSP-1), cysteine-serine-valine-threoninecysteine- glycine (CSVTCG) TSP receptor, and matrix metalloproteinase-9 (MMP-9) in colorectal cancer(Murcia : F. Hernández, 2001) Wakiyama, T.; Shinohara, T.; Shirakusa, T.; John, A.S.; Tuszynski, G.P.Thrombospondin-1 (TSP-1) is a 450 kDa matrix bound glycoprotein involved in tumor invasion, metastasis, and angiogenesis. One of the receptors involved in TSP-1 mediated tumor cell adhesion and metastasis is the cysteine-serine-valine-threoninecysteine- glycine (CSVTCG) receptor. One mechanism of TSP-1 in promoting tumor cell metastasis involves the up-regulation of matrix metalloproteinase-9 (MMP-9) expression, specifically through the CSVTCG TSP-1 receptor. TSP-1 and its CSVTCG receptor has been implicated in tumor progression in a variety of cancers including breast adenocarcinomas, head and neck squamous cell carcinomas, and pancreatic carcinomas. In this study, we examined 99 cases of colorectal cancer by immunohistochemical analysis to investigate 1) the localization of TSP-1 and CSVTCG TSP-1 receptor, 2) the relationship with MMP-9, and 3) the correlation of expression with clinical staging. Strong expression of TSP-1 was observed in the submucosa or the serosa adjacent to the tumor. Positive staining for CSVTCG TSP-1 receptor was observed in tumor cells and microvessels. MMP-9 was also expressed in tumor cells. In addition, staining intensity of CSVTCG TSP-1 receptor was higher in poorly differentiated adenocarcinoma than well or moderately differentiated adenocarcinoma. Tumors in which inflammatory cells stained strongly for CSVTCG TSP-1 receptor correlated with decreased incidence of distant metastasis and angiogenesis. These data were consistent with our previous studies for breast, pancreatic, and head and neck carcinoma. They suggest an important role for TSP-1 and CSVTCG TSP-1 receptor in tumor progression in colorectal cancer.
- PublicationOpen AccessTranscriptional regulation of the bcl-x gene encoding the anti-apoptotic Bcl-xL protein by Ets, Rel/NFKB STAT and AP1 transcription factor families(Murcia : F. Hernández, 2001) Sevilla, L.; Zaldumbide, A.; Pognonec, P.; Boulukos, K.E.Transcription factors play an essential role in determining the fate of a cell by affecting the expression of target genes involved in proliferation, in differentiation and in programmed cell death. Under certain conditions, some of these factors are capable of deregulating expression of genes involved in the cell cycle andlor in programmed cell death resulting in uncontrolled proliferation of the cell. The focus of this review is on the transcriptional regulation of the bcl-x gene encoding the anti-apoptotic Bcl-xL protein. Since 1999, severa1 papers have implicated members of the Ets, R~~/NFKSBT, N and AP-1 families as transcription factors regulating bcl-x expression. A specific emphasis of these different transcription factor families on bcl-x regulation in hematopoietic cells is discussed
- PublicationOpen AccessThe hepatocytes of the brown trout (Salmo trutta f. fario):A quantitative study using design-based stereology(Murcia : F. Hernández, 2001) Rocha, E.; Monteiro, R.A.F.; Oliveira, M.H.; Silva, M.W.A stereological study was performed on brown trout hepatocytes aiming to disclose whether there are basic gender differences when minimal levels of sex hormones exist, and also to establish a platform for both interspecific comparisons and physiological correlations. We used the so-called "design-based stereology" (with no shape, size or orientation assumptions) and also some new related statistics. Twoyear- old brown trout were collected in April, and the livers were fixed by perfusion. From liver slicing to microscopical field selection, systematic sampling was used. Stereology was applied at light and electron microscopy. Target parameters were the relative and total hepatocyte number, the mean individual hepatocyte volume and surface, and also both relative and total volumes, and surfaces, either of organelles or of cell compartments. Observed variability was usually high, but the precision of estimates was proved to be globaily adequate facing the true biological variation amongst specimens. Females had more hepatocytes per liver ( 1 . 7 9 ~ 1 0v~s. 1 . 1 2~1 0~C) .o nsidering the individual hepatocytes, whereas no gender differences were detected in the cell volume, males had higher values of nuclear volume (199 vs. 151 pm3) and surface (170 vs. 131 pm2), endoplasmic reticulum volume I 1300 vs. 824 pm3), and microvilli volume (82 vs. 54 pm ) and surface (1445 vs. 975 pm2). However, when dealing with quantities per liver, gender differences were found only in the volumes of dense bodies (56 vs. 97 mm3) and of residual cytoplasm (169 vs. 341 mm3) - both volumes were higher in females. Functional implications of data are discussed, namely that females seem to have basic structural traits for coping with the later demands of breeding. Data also support that structural remodelling of hepatocytes occurs after breeding, urging to pursue seasonal studies (namely on lysosomes). We advanced the hypothesis that genders differ in microvilli surface just to maintain an optimal physiological surface-to-volume ratio. Interspecific similarities and differences were disclosed. For example, the number of hepatocytes/cm3 of parenchyma of brown trout was much lower than those reported in rainbow trout, but in both trouts femaies seem to have an higher cell number. In addition, when comparing the size of hepatocytes of brown trout with that from other fish and mammals it was suggested that major interspecific differences exist.
- PublicationOpen AccessAppearance of vascular endothelial growth factor (VEGF) in femoral head in the growing rat(Murcia : F. Hernández, 2001) Ichigatani, M.; Saga, T.; Yamaki, K.; Yoshizuka, M.In this study, we examined the appearance of vascular endothelial growth factor (VEGF) in the femoral head of the growing rat using an immunocytochemical technique. Our results showed VEGF-immunopositive cells existed in the inner region and peripheral region of the femoral head at each developmental stage. In the 19-day-old fetus, immunopositive mesenchymal cells were demonstrated in the peripheral region of the femoral head. At 1 to 10 days after birth, VEGF immunoreactivities were observed in the osteoblasts, osteoclasts, periosteum, perichondrium and cartilage matrix of the femur. At 15 days after birth, VEGF immunoreactive chondrocytes appeared in the apex area of the femoral head. In this stage, the femoral head is still constituted by chondrocytes and no apparent vascular formation has been observed. Thereafter, the immunopositive chondrocytes in the femoral head increased in number. The penetration of capillaries was recognized within the ligament of the femoral head at 60 days after birth. The results indicate that some chondrocytes in the femoral head produce VEGF before the beginning of ossification, and that VEGF may play an important role in the penetration of blood vessels into the femoral head from the ligament of the femoral head.