PubMed Health⌕ Search

Biomedical subjects

C L Johnston

Publications and source records attributed to C L Johnston.

At least 19 recordsLinked to original sources
PubMed1997

A paracrine role for myoepithelial cell-derived FGF2 in the normal human breast.

We have studied separated normal human breast epithelial and myoepithelial cells for the presence of basic fibroblast growth factor (FGF2) and its receptors, both low (heparan sulfate proteoglycans) and high affinity (FGFR1), and for the effects of FGF2 on the proliferation of both cell types. Our results indicate that these cells differ markedly in their synthesis and response to FGF2. We found, using PCR of purified cell populations, mRNA for FGF2 only in the myoepithelial cells, whereas immunostaining and Western blotting results demonstrated the presence of FGF2 protein in both epithelial and myoepithelial cells. FGF2 had no effect on the proliferation of myoepithelial cells, but it did maintain the survival of the separated epithelial cells in low serum and stimulate their growth in 5% and 10% FCS. Immunostainable FGFR1 was present in epithelial cells and, to a lesser extent, in myoepithelial cells. Low-affinity binding sites for FGF2 were synthesized by epithelial and myoepithelial cells, but myoepithelial cells possessed a greater proportion of higher-affinity heparan sulfate proteoglycans. These results indicate that myoepithelial cell-derived FGF2 may be an important paracrine factor controlling epithelial cell survival and growth in the normal human breast.

Blotting, Southern↗
PubMed1997

Expression of keratinocyte growth factor and its receptor in human breast cancer.

The level of expression of keratinocyte growth factor (KGF) mRNA has been measured in human breast cell lines, purified populations of epithelial cells, myoepithelial cells and fibroblasts from reduction mammoplasty tissue and a panel of 42 breast cancers and 30 non-malignant human breast tissues using a semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR) procedure. We found similar levels of KGF mRNA in malignant and non-malignant breast tissues. The study of the amount of KGF mRNA in breast cell lines and purified populations of cells revealed that fibroblasts are the predominant source of KGF with malignant and non-malignant epithelial cells containing very low levels of KGF mRNA. We have examined the distribution of fibroblast growth factor receptor (FGFR)-2-IIIb, which is a high-affinity receptor for KGF and find that it is present on malignant and non-malignant epithelial cells. The level of FGFR-2-IIIb present on breast cancer cell lines was sufficient for KGF stimulation of breast cancer cell proliferation. Other members of the fibroblast growth factor family have been either not expressed in the human breast (FGF3, FGF4) or have been found at much reduced levels in breast cancer (FGF1, FGF2) and this is the first member of the family to potentially influence the progression of breast cancer through stimulation of cell division.

Breast↗
PubMed1997

The location of acidic fibroblast growth factor in the breast is dependent on the activity of proteases present in breast cancer tissue.

Acidic fibroblast growth factor (FGF1) and two of its receptors, FGFR1 and FGFR4, were localized in cryostat sections of normal, benign and malignant human breast tissue by immunohistochemistry. Without pretreatment, FGF1 staining was mainly seen in normal epithelial cells. However, polymerase chain reaction (PCR) analysis and immunoblotting of isolated normal epithelial and myoepithelial cells showed FGF1 mRNA and protein to be present in both cell types. Following incubation of frozen sections at 37 degrees C in phosphate-buffered saline, FGF1 staining was also revealed in myoepithelial cells and basement membrane adjacent to carcinoma cells. Treatment with protease inhibitors demonstrated that this effect was due to the activity of an endogenous protease. In contrast, FGF1 staining was found to be associated with the stroma adjacent to malignant cells only in the presence of protease inhibitors. FGFR1 and FGFR4 immunostaining was localized to both normal and malignant epithelial cells and to a lesser extent to myoepithelial cells. There was no difference in the staining intensity for the FGF receptors between normal and cancer samples. The change in location of FGF1 between normal and malignant tissues and the sensitivity of stored FGF1 to the action of endogenous proteases raises the possibility of both autocrine and paracrine roles for FGF1 in the normal and malignant human breast.

Animals↗
PubMed1997

Fibroblast growth factor 2 in breast cancer: occurrence and prognostic significance.

This paper examines the expression of fibroblast growth factor 2 (FGF-2) in the malignant human breast. Semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was used to assess the level of expression of FGF-2 in a series of 51 patients clinically followed up for a median of 84 months (Luqmani et al, 1992). Immunohistochemistry and Western blotting were used to show that the level of FGF-2 in breast tissues correlated with the amount of FGF-2 mRNA. FGF-2 was present in both malignant and non-malignant breast, although less was expressed in malignant tissues as determined by all three methods. Immunohistochemistry on frozen sections of breast tissue showed expression of FGF-2 in myoepithelial and epithelial cells in non-malignant samples and generally lower or undetectable levels of staining in malignant epithelial cells. The results obtained by immunohistochemistry correlated well with RT-PCR data showing similar levels of FGF-2 and FGF-2 mRNA expression in samples. No correlation was found between FGF-2 mRNA expression and T stage, nodal status or oestrogen receptor status. However, Kaplan-Meier survival plots show that higher levels of FGF-2 are associated with improved overall and disease-free survival. We suggest that FGF-2 expression may have value as a prognostic indicator in breast cancer.

Adult↗
PubMed1997

Down-regulation of a novel form of fibroblast growth factor receptor 1 in human breast cancer.

Monoclonal antibodies against two epitopes of FGFR-1 have been used to investigate FGFR-1 expression in the normal and neoplastic human breast. Different forms are detected in the different cell types constituting the normal breast. Moreover, breast cancer cells lack one form of FGFR-1. Western blot analysis showed 115-kDa and 106-kDa forms of FGFR-1 within the human breast. The 115-kDa band corresponds to the beta form of FGFR-1, whereas the 106-kDa band is truncated at the carboxyl terminus. The 106-kDa form of FGFR-1 is the major form present in breast fibroblasts and myoepithelial cells, whereas epithelial cells contain equal amounts of the 115-kDa and 106-kDa forms. Breast cancer cells, however, appear to contain only the 115-kDa form of FGFR-1. This expression pattern is reflected in malignant and non-malignant tissue samples. Using reverse transcription polymerase chain reaction (RT-PCR) analysis, we have shown that the 106-kDa FGFR-1 isoform is not the previously described alpha 2 receptor that arises from a 25-base pair insertion in the second kinase domain. It is probable that the 106-kDa FGFR-1 has different signalling properties to the full-length receptor, having lost at least one tyrosine at amino acid 766, which is required for phospholipase C activation. This form of FGFR-1 appears to be lost in all breast cancer cells analysed and its absence may have a bearing on malignancy.

Amino Acid Sequence↗
PubMed1997

Patient-focused care: what is it?

Patient-focused care is a philosophy incorporating a set of basic principles with which hospitals and other health care institutions organize and facilitate administration and delivery of the caring continuum. The pattern advocates fundamental change in basic operations and structuring of care delivery and projects considerable cost savings based on that change in utilization and organization of resources, staff, capital equipment, and the physical plant. Increased customer and professional staff satisfaction and creation of a learning organization that is ready to move with the fast-paced change inherent in today's health care delivery system are examples of projected benefits from implementation of this model.

Cost Savings↗
PubMed1997

Changing care patterns and registered nurse job satisfaction.

Job satisfaction for registered nurses continues to be a source of conflict and dissension within the health care delivery system. The acute shortage of registered nurses in previous decades has abated, but turnover has not. Reengineering, restructuring, and other new care delivery organizational patterns are being implemented as cost savings are sought. A cross-sectional descriptive survey of a nursing organization was conducted on the eve of implementation of a change in the care pattern at a large, acute care institution. Although results indicated a low level of job satisfaction overall, the nurses indicated that there was respect and value for nursing within the institution.

Adult↗
PubMed1996

Job satisfaction: a possibility?

Registered nurse job satisfaction is one of the most written about topics in the nursing literature. Is it possible to achieve in an organizational setting? Can the administrative structures control this phenomenon? This article suggests that job satisfaction is strongly influenced by individual perceptions of certain key variables. In addition, job satisfaction is presented as a responsibility of each individual nurse.

Attitude of Health Personnel↗
PubMed1995

Fibroblast growth factor receptors (FGFRs) localize in different cellular compartments. A splice variant of FGFR-3 localizes to the nucleus.

We have raised specific antibodies to the second immunoglobulin-like domain of fibroblast growth factor receptors (FGFRs) and used these to investigate the expression and subcellular localization of FGFR-1, -2, -3, and -4 in breast epithelial cells. All four receptors classes could be detected in breast cell lines; however, FGFR-4 and FGFR-2 appeared to be expressed at a higher level in breast cancer cell lines than in normal epithelial cells. Surprisingly, FGFR-3 localized in the cell nucleus by immunofluorescence. A second antibody to a separate epitope confirmed this finding and showed that the form of FGFR-3 present must contain an intact kinase domain as well as the growth factor binding domain. Western analysis of fractionated cells revealed the presence of two forms of FGFR-3 of 135 and 110 kDa. The 110-kDa form was predominantly found in the nucleus, whereas the 135 kDa form was sometimes found in the nucleus. RT-PCR analysis of FGFR-3 mRNA showed the presence of a splice variant in which exons 7 and 8 are deleted. This results in the translation of FGFR-3 missing the transmembrane domain but with an intact kinase domain, which could be a soluble, intracellular receptor. Transfection experiments showed that FGFR-3 containing this deletion and no signal peptide gave an identical nuclear staining pattern to that seen in breast epithelial cells. We conclude that two forms of FGFR-3 are present in breast epithelial cells; a full-length 135-kDa receptor, which has a conventional membrane localization, and a novel soluble form of 110 kDa.

Alternative Splicing↗
PubMed1995

Expression of 2 variant forms of fibroblast growth factor receptor 1 in human breast.

The expression of variant mRNAs encoding isoforms of fibroblast growth factor receptor (FGFR)1 with either 2 or 3 Ig-like loops in the extracellular domain was investigated in human breast tissues and cell lines using a polymerase chain reaction amplification method. Almost all tissues contained both forms of FGFR1, but cancers (n = 137) had a significantly lower proportion of the transcript that encoded the full 3-loop form compared with non-malignant biopsies (n = 34). This was confirmed using microdissected populations of normal and cancerous cells from frozen tissue sections. A high ratio of the 2- to 3-loop form was found to be predictive of reduced relapse-free survival. In both groups, however, the predominant form of FGFR1 was that encoding the 2-loop receptor. Cell lines derived from a variety of tissues, including breast, also co-expressed both variants of FGFR1, suggesting their presence within the same cell type. Again, there was a similar preponderance of the shorter isoform. Our results were confirmed at the protein level, where out of 5 cancers analysed 4 expressed more of the 2-loop form than the 3-loop form. Our findings suggest that cells may normally simultaneously express several splice variants of FGFR1, and aberrant expression or a change in their relative amounts (i.e., in malignancy) could contribute to modified responses to either autocrine or paracrine factors.

Adult↗
PubMed1995

bFGF and aFGF induce membrane ruffling in breast cancer cells but not in normal breast epithelial cells: FGFR-4 involvement.

Acidic and basic fibroblast growth factors (aFGF and bFGF) are growth factors which may have a physiological role in the normal breast and in breast cancer. A study of the effects of aFGF and bFGF on a variety of breast cell lines and epithelial cells purified from normal breast organoids showed that whereas normal breast cells did not exhibit membrane ruffling in response to either of these growth factors, some breast cancer cell lines did. This difference was not due to lack of receptor since all the cell lines tested were mitogenically stimulated by bFGF. Dominant negative mutations of FGF receptor 3 (FGFR-3) and the small GTP-binding protein p21rac inhibited membrane ruffling, showing that receptor dimerization and phosphorylation and p21rac activation are prerequisites for membrane ruffling in response to aFGF and bFGF. Transient transfection of individual FGFRs into cos-7 cells showed that FGFR-1, FGFR-2 and FGFR-3 could not mediate a membrane ruffling response whereas FGFR-4 could. These studies elucidate one signalling mechanism of FGF and point to differences in the response of normal and cancer breast epithelial cells which may be important in cell motility.

3T3 Cells↗
PubMed1995

Expression of fibroblast growth factor 1 is lower in breast cancer than in the normal human breast.

We have measured the amount of fibroblast growth factor 1 (FGF-1) mRNA and protein in primary breast cancers and non-malignant breast tissue and have found greatly reduced levels in breast cancer compared with non-malignant tissue. A total of 116 breast cancers and 37 biopsies taken from non-malignant breast were compared for FGF-1 mRNA expression using reverse transcriptase-polymerase chain reaction (RT-PCR) and significantly lower levels were found in the cancer tissues (P < 0.001). These findings were confirmed at the protein level where four out of five breast cancers contained no detectable FGF-1 and a fifth cancer had a low level of FGF-1 compared with three samples from reduction mammoplasties. Similar results were obtained from breast cell lines in which 80% of cancer cell lines had very low levels of FGF-1, whereas all non-malignant breast cell lines contained higher levels of FGF-1. Immunohistochemical analysis indicated that FGF-1 was present in the luminal epithelial cells of the non-malignant breast but was absent from cancer cells. The decreased levels of FGF-1 in breast cancer may indicate that stimulation of cancer cells is resulting in down-regulation of FGF-1 expression or may implicate FGF-1 as a differentiation factor rather than a growth factor at its physiological concentration in the breast.

Adult↗
PubMed1995

Restructuring. Implications for nursing administration education.

The Council on Graduate Education for Administration in Nursing (CGEAN) was established to further develop and improve graduate education for administration in nursing. The Council seeks to identify the nature and direction of education for administration in nursing in various healthcare systems, providing guidelines for programs offering administration. A major goal of CGEAN is facilitating dialogue between nursing service administrators and graduate level educators who are engaged in teaching and research related to administration in nursing. This column, sponsored by the members of the Council, analyzes and responds to position statements and trends related to the delivery of health services and graduate education for administrators in nursing.

Delivery of Health Care↗
PubMed1992

The small GTP-binding protein rac regulates growth factor-induced membrane ruffling.

The function of rac, a ras-related GTP-binding protein, was investigated in fibroblasts by microinjection. In confluent serum-starved Swiss 3T3 cells, rac1 rapidly stimulated actin filament accumulation at the plasma membrane, forming membrane ruffles. Several growth factors and activated H-ras also induced membrane ruffling, and this response was prevented by a dominant inhibitory mutant rac protein, N17rac1. This suggests that endogenous rac proteins are required for growth factor-induced membrane ruffling. In addition to membrane ruffling, a later response to both rac1 microinjection and some growth factors was the formation of actin stress fibers, a process requiring endogenous rho proteins. Using N17rac1 we have shown that these growth factors act through rac to stimulate this rho-dependent response. We propose that rac and rho are essential components of signal transduction pathways linking growth factors to the organization of polymerized actin.

3T3 Cells↗