A growth regulatory factor that can both inhibit and stimulate growth

A growth inhibitor that is produced by BSC-1 cells (African green monkey kidney epithelial cells) has been isolated from conditioned medium. It has been purified by gel chromatography and high performance liquid chromatography. It appears to be a protein with a relative molecular mass (Mr) of 24 000. It is extremely active as a growth inhibitor with some cells, but not with others. Approximately 50% inhibition of thymidine incorporation is observed with CCL64 cells at 0.05 ng/ml and with BSC-1 cells at 1 ng/ml. The growth inhibitor induces BSC-1 cells to synthesize and secrete a glycoprotein of approximately 48 000 Mr. It inhibits Na+ accumulation in BSC-1 cells. Recently, in collaboration with R. F. Tucker, G.D. Shipley and H. L. Moses (Mayo Foundation & Medical School), we have found that the growth inhibitor is very similar to and may be identical with transforming growth factor beta (TGF-beta). Our growth inhibitor stimulates colony formation in soft agar by AKR-2B cells, and it competes with TGF-beta in binding to cell surface receptors. TGF-beta, from human platelets, is extremely active as an inhibitor of thymidine incorporation by BSC-1 cells and CCL64 cells. The growth inhibitor/TGF-beta can, therefore, stimulate or inhibit growth, depending on the cells and the growth conditions.

The Multidimensional Health Behavior Inventory

Gaps in knowledge about what constitutes healthy and risky behaviors for young people hinder successful health promotion intervention strategies. With the development of appropriate instruments, behaviors can be measured and interventions can be implemented to improve health outcomes. The structure of a new health behavior instrument, the Multidimensional Health Behavior Inventory (MHBI), was explored with data from 1,077 college students, ages 18 to 24 years. Factor analysis of 116 health behavior questions yielded 7 factor-based scales with 57 items: diet (13 items), substance use (10 items), safety (9 items), checkup (9 items), social (6 items), stress (6 items), and exercise (4 items). Evaluation of the 7 behavior scales of the MHBI using subgroups defined by age, gender, and race will contribute to an understanding of health behaviors of older adolescents and young adults and will provide directions for research and clinical interventions.

Mom empowerment, too! (ME2): a program for young mothers involved in substance abuse

Substance abuse among young people is of critical concern to public health nurses. When substance abusers are young mothers without the skills, experience, guidance, or resources to become adequate parents, this problem is compounded This study examined a community-based intervention program for young mothers from the perspective of 42 participants. A qualitative, descriptive design was used within a process of participatory action research. Two major domains emerged from the data: risk perceptions and behaviors, and health promoting perceptions and behaviors. The study demonstrated the value of obtaining data from the participants and offers implications for practice and research.

The Shifting Sands of Health Care Delivery: Curriculum Revision and Integration of Community Health Nursing

The health care delivery system in the United States is moving from an institutionally driven and controlled medical care model toward the Primary Health Care model described by the Alma-Alta Conference (World Health Organization [WHO], 1978) as community-driven comprehensive health care. However, nursing education still remains institutionally based, anchored in a medical model. Dynamic curricula must be developed that prepare nurses to practice in an ever-changing health care delivery system that is becoming more community based. The purpose of this article is twofold: to provide an overview of the revised curriculum of Brigham Young University's College of Nursing (BYU-CON) as one example of a faculty's attempt to develop a program that prepares graduates skilled in providing health care in the 21st century; and to examine closely the integration of community health nursing into the curriculum.

Population-focused and community-based nursing--moving toward clarification of concepts

Rapid health care delivery system changes combined with the Institute of Medicine's (1988) call for refocusing public health practice into the Core Functions provide an opportunity to shape community/public health nursing (C/PHN) education and practice for the future. Critical examination is the key to clarifying C/PHN practice. What is the practice now? Is it population-focused, community-based, or both? And what do these terms mean today? The purpose of this paper is to share the authors' thinking about what it is that makes population-focused nursing "different" from community-based practice, as well as unique and useful to the health care delivery system, through the examination of old and new terms and concepts. The significance of this article lies in its ability to encourage dialogue among our colleagues. It is hoped that thoughts shared here will stimulate action to define C/PHN practice in broader arenas.

Advancing discourse on health promotion: beyond mainstream thinking

Attention must be redirected toward health promotion as nursing evaluates the goal of health for all. Confusion regarding health promotion behavior is illustrated by terms with diverse meanings and uses. In a process of critical analysis, five multidisciplinary experts in health promotion responded to a survey targeting the distinction of health promotion, health promotion behavior, health protection behavior, disease prevention behavior, preventive health behavior, health behavior, and healthy lifestyle. Descriptors of health promotion were derived from a multidimensional conception of well-being. Disagreement existed concerning health protection and health behavior. Nursing interventions are linked to reflective discourse regarding health promotion behavior.

Are we implementing community health promotion in nursing?

Promoting the health of communities has been the rallying cry (now renewed) from the nation's top public health officials. Public health nurses have always stressed community health promotion, not only in their work but also in the educating of future public health nurses. Facilitating the shift from focusing primarily upon secondary and tertiary prevention, individual, and disease-oriented processes is a constant challenge, given the current health care and reimbursement systems. The objectives of this paper are: to give a brief historical review of the nation's health objectives, other recent pertinent documents, and early public health nursing's emphases regarding community health promotion; to give a selected overview of recent community health promotion programs implemented by community and public health nurses in nursing education and practice; and to focus on present challenges to nursing in implementing community health promotion.

From preventive health behavior to health promotion: advancing a positive construct of health

A concept analysis of preventive health behavior provided the foundation for this review of current health promotion research in nursing. Studies selected for review described or explained behavior for health promotion, illness prevention, or preventive health behavior. The major focus of this critical review is on the conceptualization and measurement of health promotion behaviors being investigated. Despite nursing's claim to an holistic idea of health, the biomedical model continues to influence indicators of health behavior and the context for promotion of healthy life styles. Major issues for future health promotion research relate to the lack of attention to theoretical definitions and multidimensional aspects of health behavior, and the triad of national strategies for health promotion are discussed.

Amino acid sequence of the BSC-1 cell growth inhibitor (polyergin) deduced from the nucleotide sequence of the cDNA

The complete amino acid sequence of the BSC-1 cell growth inhibitor, including its precursor polypeptide, is reported. The sequence was deduced from the nucleotide sequence of the cDNA. The N-terminal amino acid sequence of the mature bioactive BSC-1 cell growth inhibitor is identical with the N-terminal sequences of the factors that have been called type beta 2 transforming growth factor and cartilage-inducing factor B, suggesting that these are identical. The complete amino acid sequence of the mature BSC-1 cell growth inhibitor differs from that of human type beta transforming growth factor in 32 of the 112 amino acids. Polyergin is proposed as the name for the BSC-1 cell growth inhibitor.

An Investigation of Decision Theory: What are the Effects of Teaching Cue Recognition?

As currently formulated, decision theory assumes that care givers learn cue recognition primarily by experience. However, it seems probable that the ability to receive and recognize cues can be taught. To investigate cue recognition abilities of junior and senior baccalaureate nursing students, five computer simulations were developed. The specific question investigated was: What are the effects upon students' cue recognition and clinical decision-making abilities of teaching cue recognition? Following teaching of cue recognition and decision making, a statistically significant difference was noted in both junior and senior students in relation to accuracy of cue recognition and clinical decision making. The conclusions were that cue recognition and cue sorting can be taught. Also, linking or grouping of related cues can be taught. In this study, the teaching of cue recognition and linking of cues improved the accuracy of clinical decisions made by students who were presented computer simulations of a variety of clinical situations.

Activity of a kidney epithelial cell growth inhibitor on lung and mammary cells

A kidney epithelial cell growth inhibitor, isolated from BSC-1 cell-conditioned medium, has been found to be active on certain lung and mammary gland cell lines in culture. The most responsive cell observed thus far is the CCL64 mink lung cell line. With CCL64 cells, 60% inhibition of [3H]thymidine incorporation is observed at a 0.1 nanogram/ml concentration of the growth inhibitor, and approximately 95% inhibition at 1 nanogram/ml. A human mammary tumor cell line, Hs578T, shows 75% inhibition of [3H]thymidine incorporation, in cell culture. Preliminary studies indicate that injection of the kidney epithelial cell growth inhibitor in vivo into human mammary carcinomas growing in nude mice inhibits [3H]thymidine incorporation in the tumors.

Purification of kidney epithelial cell growth inhibitors

Two high molecular weight growth inhibitors have been isolated from the culture medium of BSC-1 cells, epithelial cells of African green monkey kidney. The purified kidney epithelial cell growth inhibitors, at ng/ml concentrations, reversibly arrest the growth of BSC-1 cells in the G1 phase of the cell cycle. Their action is selective; they are most active on BSC-1 cells, are less active as inhibitors of the growth of rat lung and human breast epithelial cells, and do not inhibit the growth of 3T3 mouse embryo fibroblasts ad human skin fibroblasts in culture. Their growth inhibitory action on BSC-1 cell cultures is counteracted by epidermal growth factor or calf serum.

Density-dependent regulation of growth of BSC-1 cells in cell culture: growth inhibitors formed by the cells

Inhibitors formed by a monkey epithelial cell line, BSC-1, play an important role in limiting growth at high cell densities. At least three inhibitors are formed: lactic acid, ammonia, and an unidentified inhibitor that may be an unstable protein. The unidentified inhibitor is destroyed by shaking the conditioned medium, by bubbling gas through the medium, or by heating or storing the medium in the absence of cells. The concentrations of lactic acid and ammonia that accumulate in conditioned medium inhibit growth when added to fresh medium. These results, together with earlier studies, indicate that density-dependent regulation of growth of BSC-1 cells results from the combined effects of (a) inhibitors formed by the cells, (b) decreased availability of receptor sites for serum growth factors as the cells become crowded, and (c) limiting concentrations of low molecular weight nutrients in the medium. In contrast, density-dependent regulation of growth in 3T3 mouse embryo fibroblasts results almost entirely from inactivation of serum factors.

Density-dependent regulation of growth of BSC-1 cells in cell culture: control of growth by low molecular weight nutrients

BSC-1 cells, epithelial cells of African green monkey kidney origin, show pronounced density-dependent regulation of growth in cell culture. Growth of the cells is rapid to a density of approximately 1.5 x 10(5) cells/per cm(2) in Dulbecco-modified Eagle's medium supplemented with 10% calf serum. Above this "saturation density," growth is much slower. It has been found that the glucose concentration in the culture medium is important in determining the "saturation density." If the glucose concentration is increased 4-fold, the "saturation density" increases approximately 50%. Reduction of the "saturation density" of BSC-1 cells is also possible by decreasing the concentrations of low molecular weight nutrients in the culture medium. In medium supplemented with 0.1% calf serum, decreasing the concentrations of all of the organic constituents of the medium, from the high levels present in Dulbecco-modified Eagle's medium to concentrations near physiological levels, decreases the "saturation density" by approximately half. The decreased "saturation density" is not the result of lowering the concentration of any single nutrient but rather results from reduction of the concentrations of several nutrients. When the growth of BSC-1 cells is limited by low concentrations of all of the nutrients, some stimulation of growth results from increasing, separately, the concentrations of individual groups of nutrients, but the best growth stimulation is obtained by increasing the concentrations of all of the nutrients. The "wound healing" phenomenon, one manifestation of density-dependent regulation of growth in cell culture, is abolished by lowering the concentration of glutamine in the medium. Density-dependent regulation of growth of BSC-1 cells in cell culture thus appears to be a complex phenomenon that involves an interaction of nutrient concentrations with other regulatory factors.

Density-dependent regulation of growth of BSC-1 cells in cell culture: control of growth by serum factors

BSC-1 cells grow slowly, to high cell density, in medium with 0.1% calf serum. An increase in the serum concentration increases both the growth rate of the cells and the final cell density. The serum can be replaced to some extent by epidermal growth factor (EGF). Initiation of DNA synthesis in BSC-1 cells that have spread into a "wound" in a crowded cell layer requires the addition of a trace of serum or EGF, if the cells have previously been deprived of serum. The binding of 125I-labeled EGF to low-density and high-density BSC-1 cells has been studied. Binding is faster to low-density cells. Cells at low cell density also bind much more EGF per cell than cells at high cell density. The fraction of bound 125I-labeled EGF that is present on the cell surface as intact EGF is larger at low than at high cell density. The results indicate that the number of available EGF receptors per cell decreases drastically as the cell density increases. It is suggested that a decrease in the number of available EGF receptor sites per cell, and the accompanying decrease in sensitivity of the cells to EGF, contributes to density-dependent regulation of growth of these cells.

Control of growth of benzo(a)pyrene-transformed 3T3 cells

The growth controls observed in benzo[a]pyrene-transformed 3T3 cells (BP3T3) are compared with those of virus-transformed and normal 3T3 cells. Superficially, the chemically transformed BP3T3 cells have the same behavior as virus-transformed SV3T3 cells. Both grow to high cell density in culture medium with 10% serum, both form colonies in Methocel, and both are tumorigenic. Closer examination, however, has disclosed that BP3T3 cells exhibit "normal" growth controls at low serum concentrations. In contrast to the behavior of SV3T3 cells, the initiation of DNA synthesis in BP3T3 cells is still dependent on a serum factor. If BP3T3 cells are grown in medium with 0.2% serum, the cells become quiescent, with growth arrested in the Gu or G0 phase of the cell cycle. The addition of serum or the fibroblast growth factor (FGF) to such quiescent cells leads to the initiation of DNA synthesis and the resumption of growth. As with normal 3T3 cells, if the growth rate of BP3T3 cells is limited by a suboptimal concentration of serum, the growth rate of the cells is increased by the addition of FGF. Also, BP3T3 cells show density-dependent regulation of growth, if the medium contains a low concentration of serum. BP3T3 cells, therefore, have the behavior of "transformed" cells when cultured in medium with 10% serum, but behave as "normal" cells in medium with low serum. In comparison with normal 3T3 cells, the difference in growth behavior of BP3T3 cells appears to be due to a substantial decrease in the cells' requirement for a serum growth factor of the FGF type. Exploration of possible causes of this substantial decrease indicates that the primary cause is a lower rate of depletion of the serum growth factor from the culture medium by BP3T3 cells. The decrease in rate of depletion is sufficient to account for the uncontrolled growth of BP3T3 cells in medium with 10% serum. It is suggested that a decreased rate of depletion of a growth factor may contribute to tumorigenicity of cells in vivo.

Regulation of guanylate and adenylate cyclase activities by lysolecithin

The guanylate cyclase activity [GTP pyrophosphate-lyase (cyclizing), EC 4.6.1.2] in membrane preparations from 3T3 mouse fibroblasts is stimulated approximately 5-fold by lysolecithin at concentrations of 100 mug/ml and above.

Control of growth of a tumor cell by linoleic acid

The growth of mouse myeloma XS 63.5 cells in cell culture is dependent on serum. Among the several growth factors present in serum, the lipid fraction is highly active. The growth factor(s) provided by the serum lipid fraction can be replaced by unsaturated fatty acids. If XS 63.5 cells are cultured in medium that is low in serum lipids, the cells become quiescent, with most of the cells in the G(1) (or G(0)) phase of the cell cycle. Addition of linoleic acid to such quiescent cells leads to reinitiation of DNA synthesis and growth.