bluuebunny/crossref_metadata_2025_split huggingface dataset:
Homocysteine Enhances Bone Resorption by Stimulation of Osteoclast Formation and Activity Through Increased Intracellular ROS Generation
Authors: Koh Jung-Min , Lee Young-Sun , Kim Yang Soon , Kim Duk Jae , Kim Hong-Hee , Park Joong-Yeol , Lee Ki-Up , Kim Ghi Su 
Published: July 2006

Abstract
Hyperhomocystinemia is a modifiable risk factor for osteoporosis and fracture. Physiologic concentrations of Hcy directly activate osteoclast formation and activity through stimulation of p38 MAPK and integrin β3. The effects of Hcy were mediated by generation of intracellular ROS.
Introduction: Hyperhomocysteinemia is a modifiable risk factor for osteoporosis and its related bone fractures. It has been reported that bone resorption and turnover rate were increased in hyperhomocystinemia. Using mouse bone marrow cells, we examined the direct effects of homocysteine (Hcy) on osteoclast formation and activity.
Materials and Methods: Osteoclast formation was determined by TRACP staining and TRACP activity. Intracellular reactive oxygen species (ROS) generation was measured using a fluorescent probe, dichlorodihydrofluorescein diacetate. Intracellular signaling cascades of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and NF-κB were measured by Western blotting. Integrin β3 mRNA levels were measured by RT-PCR. Actin ring formation and bone resorption assays were also performed.
Results: Physiologic concentrations of Hcy upregulated TRACP+ multinucleated cells and TRACP activity, stimulated actin ring formation, and increased the number of nuclei per cell and the level of expression of integrin β3 mRNA. In addition, Hcy increased bone resorption and stimulated p38 MAPK activity and intracellular reactive oxygen species (ROS) generation. All of these Hcy-induced changes were blocked by pretreatment with the antioxidant, N-acetyl cysteine.
Conclusions: Hcy directly activates osteoclast formation and activity through increased generation of intracellular ROS. These findings suggest that, in individuals with mild to moderate hyperhomocystinemia, increased bone resorption by osteoclasts may contribute to osteoporosis and that an antioxidant may attenuate bone loss in these individuals.
Expression of Mouse Osteoclast K-Cl Co-Transporter-1 and Its Role During Bone Resorption
Authors: Kajiya Hiroshi , Okamoto Fujio , Li Jing-Ping , Nakao Akihiro , Okabe Koji 
Published: July 2006

Abstract
To assess the role of Cl− transport during osteoclastic bone resorption, we studied the expression and function of K+/Cl− co-transporters (KCCs). KCC1 and chloride channel-7 were found to be expressed in mouse osteoclasts. The KCC inhibitor, R(+)-butylindazone (DIOA), KCC1 antisense oligo-nucleotides, and siRNA suppressed osteoclastic pit formation. DIOA also decreased Cl− extrusion and reduced H+ extrusion activity. These results show that KCC1 provides a Cl− extrusion mechanism accompanying the H+ extrusion during bone resorption.
Introduction: Mice with deficient chloride (Cl−) channels, ClC7, show severe osteopetrosis, resulting from impairment of Cl− extrusion during osteoclastic bone resorption. However, the expression and functional role of Cl− transporters other than ClC7 in mammalian osteoclasts is unknown. The aim of this study was to determine expression of K+/Cl− co-transporters (KCCs) and their functional role for bone resorption in mouse osteoclasts.
Materials and Methods: Mouse osteoclasts were derived from cultured bone marrow cells with macrophage-colony stimulating factor (M-CSF) and RANKL or from co-culture of bone marrow cells and primary osteoblasts. We examined the expression of Cl− transporters using RT-PCR, immunochemical, and Western blot methods. The effects of Cl− transport inhibitors on H+ and Cl− extrusion were assessed by measuring intracellular H+ ([H+]i) and Cl− ([Cl−]i). The effects of inhibitors, antisense oligo-nucleotides, and siRNA for Cl− transporters on bone resorption activities were evaluated using a pit formation assay.
Results and Conclusions: Mouse osteoclasts express not only ClC7 but also K+/Cl− co-transporter mRNA. The existence of KCC1 in the cell membrane of mouse osteoclasts was confirmed by immunochemical staining and Western blot analysis. KCC inhibitors and Cl− channels blockers increased [Cl−]i and [H+]i in resorbing osteoclasts, suggesting that the suppression of Cl− extrusion through KCC and Cl− channels leads to reduced H+ extrusion activity. The combination of both inhibitors greatly suppressed these extrusion activities. KCC inhibitors and Cl− channel blockers also decreased osteoclastic bone resorption in our pit area essay. Furthermore, KCC1 antisense oligo-nucleotides and siRNA suppressed osteoclastic pit formation as well as treatment of ClC7 inhibitors. These results indicate that K+/Cl− co-transporter-1 expressed in mouse osteoclasts acts as a Cl− extruder and plays an important role for H+ extrusion during bone resorption.
Pathogenic Role of Connective Tissue Growth Factor (CTGF/CCN2) in Osteolytic Metastasis of Breast Cancer
Authors: Shimo Tsuyoshi , Kubota Satoshi , Yoshioka Norie , Ibaragi Soichiro , Isowa Sachiko , Eguchi Takanori , Sasaki Akira , Takigawa Masaharu 
Published: July 2006

Abstract
The role of CTGF/CCN2 in osteolytic metastasis by breast cancer cells and its mechanism of action were studied. Osteolytic metastasis accompanied by CCN2 and PTHrP overproduction was efficiently inhibited by an anti-CCN2 antibody. Furthermore, we found that CCN2 was induced by PTHrP through PKA-, PKC-, and ERK-mediated pathways therein.
Introduction: Connective tissue growth factor (CTGF/CCN2) is a mediator of local angiogenesis induced by breast cancer, but its role in osteolytic metastasis has not been evaluated. PTH-related peptide (PTHrP) is another critical factor in the development of the osteolytic metastasis. Using both in vivo and in vitro approaches, we studied whether/how neutralization of CCN2 prevented bone metastasis and how PTHrP signaling is related.
Materials and Methods: A mouse model of bone metastasis by human breast cancer cell line MDA231 was treated with a CCN2-neutralizing antibody, and osteolytic bone metastases were assessed on radiographs and immunohistochemistry. Ccn2 gene expression and transcription were examined by Northern blot and luciferase analysis. Immunoblot analysis and kinase inhibitors were used to identify the signaling pathways implicated. Anti-angiogenic/osteoclastogenic effects of ccn2 downregulation were also evaluated.
Results: Treatment of mice with a CCN2-neutralizing antibody greatly decreased osteolytic bone metastasis, microvasculature, and osteoclasts involved. The antibody also suppressed the growth of subcutaneous tumor in vivo and proliferation and migration of human umbilical vein endothelial cells (HUVECs) in vitro. Downregulation of ccn2 also repressed osteoclastogenesis. CCN2 expression was specifically observed in cancer cells producing PTHrP and type I PTH/PTHrP receptor (PTH1R) invaded the bone marrow, and PTHrP strongly upregulated ccn2 in MDA231 cells in vitro. Activation of protein kinase C (PKC) and protein kinase A (PKA) was necessary and sufficient for the stimulation of ccn2 by PTHrP. Indeed, inhibition of the extracellular signal-regulated kinase (ERK1/2), PKC, or PKA by specific inhibitors counteracted the stimulation of ccn2 expression. Incubation of MDA231 cells with PTHrP induced the activation of ERK1/2. Consistent with these findings, inhibition of PKC prevented PTHrP-induced ERK1/2 activation, whereas 12-O-tetradecanoylphorbol13-acetate (TPA), a stimulator of PKC, upregulated it.
Conclusions: CCN2 was critically involved in osteolytic metastasis and was induced by PKA- and PKC-dependent activation of ERK1/2 signaling by PTHrP. Thus, CCN2 may be a new molecular target for anti-osteolytic therapy to shut off the PTHrP–CCN2 signaling pathway.
Relationship Between Bone Quantitative Ultrasound and Fractures: A Meta-Analysis
Authors: Marín Fernando , González-Macías Jesús , Díez-Pérez Adolfo , Palma Silvia , Delgado-Rodríguez Miguel 
Published: July 2006

Abstract
The relationship between bone QUS and fracture risk was estimated in a systematic review of data from 14 prospective studies of 47,300 individuals and 2350 incident fractures. In older women, low QUS values were associated with overall fracture risk, low-trauma fractures, and with hip, forearm, and humerus fractures separately.
Introduction: Bone quantitative ultrasound (QUS) has emerged as a promising technique to evaluate bone status. The aim of this study was to determine the association between measurements of QUS with the risk of fracture.
Materials and Methods: A meta-analysis of prospective cohort studies published between 1985 and June 2005 with a baseline measurement of QUS and subsequent follow-up for fractures was carried out. Fourteen separate study populations, consisting of about 47,300 individuals (85.4% women), with about 124,000 person-years of observation and over 2350 fractures, including 653 hip, 529 forearm, and 386 humeral fractures, were analyzed. The main outcome measure was the estimated relative risk of fracture for a decrease in bone QUS parameters of 1 SD below sex- and age-adjusted mean in women.
Results: Eleven studies evaluated QUS at the heel, with patella and phalanx (two studies each) and distal radius (one study) being scarcely used. There was not significant heterogeneity among the studies included in the review. Relative risk estimates (95% CI) for overall fractures were 1.55 (1.35–1.78) for each SD decrease in broadband ultrasound attenuation (BUA), 1.63 (1.37–1.93) for speed of sound (SOS), and 1.74 (1.39–2.17) for QUS index/stiffness index (QUI/SI). Risk estimates were similar or slightly higher for hip fractures and low-energy trauma fractures. Humeral and forearm/wrist fractures were also related with lower QUS values.
Conclusions: Measurements of bone QUS are significantly associated with nonspinal fracture risk in older women in a similar degree to DXA. QUS may be a valid alternative to evaluate fracture risk in situations where DXA is not accessible.
Management Entry Into U.S. Agriculture
Authors: Tolley G. S. 
Published: July 2006

AbstractThe view that agriculture is undergoing replacement of one kind of human capital by another is offered as alternative to the traditional view that resources are chronically oversupplied to farming. The hypothesis that high level management farms have experienced favorable cost curve shifts explains farm number declines as primarily replacement of many low management by fewer high management farms. The replacement raises efficiency modestly. Occupational supply behavior relations for management levels lead to inferences about income distribution and future structure of agriculture. A price‐income policy is suggested to compensate outmoded management for obsolescence.
The Investment Behavior of a Farm Firm Operating under Risk
Authors: Sadan Ezra 
Published: July 2006

AbstractThe opportunities facing the investment decision maker in a farm firm operating under risk can be summarized in some cases in terms of “efficiency frontiers,” the dimensions of which are the expected present value and the variance of the farm's future net returns. This article attempts to trace and define these frontiers in terms of deductible algebraic equations in simplified single‐ and multiperiod cases where the farm output level is determined by a single systematic input variable—capital—and a single random factor and where the functional relationship is Cobb‐Douglas. It also attempts to outline, through simulation procedures, the frontiers pertaining to a “real world” case of a growing farm cum household unit.
The Measurement of Efficiency Relative to a Frontier Production Function
Authors: Seitz Wesley D. 
Published: July 2006

AbstractA method is presented for estimating a frontier production function allowing economies and diseconomies of scale using linear programming techniques. The general applicability of this function is illustrated by considering the neutral and nonneutral cases. Indexes of technical, price, and economic efficiency of production of observations of equal scale are introduced. Three equivalent efficiency indexes are offered which measure the efficiency of alternative scale activities. Utilization of the efficiency indexes in determining the nature of the production function, causes of observed inefficiency, and the degree and nature of technological advance are discussed.
An Experimental Comparison of Pricing in Two Auction Systems
Authors: Frahm Donald G. , Schrader Lee F. 
Published: July 2006

AbstractTrading and pricing procedures are being increasingly viewed as variables in the marketing system, particularly as the pricing role of central markets declines. Quantification of the effect of pricing systems on price outcome is needed for decisions in this area. English (ascending bid) and Dutch (descending price) auctions are compared in a series of experiments. Specific hypotheses regarding price variation, pattern of price during an auction period, and departure from equilibrium price are tested. The experimental evidence indicates the existence of a significant area of indeterminacy in pricing processes.
Economic Determinants of the Farm and Elevator Trends in the Volume of Corn Artificially Dried
Authors: Hill Lowell D. 
Published: July 2006

AbstractThe trend toward on‐farm drying of corn is not consistent with the economic advantage of the elevator in performing the drying function. This study examines the factors that have influenced this trend, using four related analytical models: (1) an aggregate model using county census data; (2) a profit‐maximization model of individual farmers; (3) a weighted regression of ownership probabilities based on farm and elevator survey data; and (4) a regression model of behavior response by market areas. Results of these models provide a composite picture of the relationships influencing the decision to dry corn on the farm. Three independent sources of data add validity to the overall conclusions.
Impact of Public Land Programs on Local Government Finances
Authors: Barron James C. , Jansma J. Dean 
Published: July 2006

AbstractPublic land ownership is often assumed to adversely affect the fiscal capacity of local governments through removal of part of the property tax base. A method employing multiple regression analysis was developed to test this hypothesis in a forested region of Pennsylvania. Neither higher tax rates on private land nor reduced levels of per capita local government expenditures were found to be associated with large amounts of public land, thereby indicating that local governments are not placed at an economic disadvantage by public land programs. Extended use of this analytical technique could result in better public policy decisions on resource use.
Temporal Relationships Among Prices on Commodity Futures Markets: Their Allocative and Stabilizing Roles
Authors: Tomek William G. , Gray Roger W. 
Published: July 2006

AbstractThe role that futures markets play in guiding inventories, through hedging, has been emphasized in economic literature. Historically, futures markets first emerged for the annual crops that could be continuously stored (grain and cotton); hence inventory hedging has been important from the outset. But forward pricing which was not attendant upon inventories has long been practiced, and the more recent emergence of futures markets for non‐inventory commodities dramatizes this fact. We show here that the model of intertemporal price relationships differs for the two cases and provide evidence for selected commodities. The contrasting implications for allocation and stabilization are also drawn.
An Intertemporal Analysis of the Nature of Demand for Food Products
Authors: Harmston Floyd K. , Hino Hiroyuki 
Published: July 2006

AbstractChanges in “taste” are very important in the demand for food products. Most analyses, however, assume taste to be a constant. By utilizing a natural log polynomial function for the Engel curve and examining the resultant income elasticities of demand, certain refinements of standard classifications of commodities are possible. These can then be used to analyze changes in taste over time. The results indicate that taste is highly variable. Further, changes in taste are significantly different for different kinds of food. Recent unprecedented shifts in family income make it imperative that there be better understanding of the nature of demand.
The Reasons Participants Drop Out of the Food Stamp Program: A Case Study and Its Implications
Authors: Love Harold G. 
Published: July 2006

AbstractIn 1967–69 about one‐fourth of all potentially eligible households participated in the St. Louis food stamp program. The annual turnover rate approximated 100 percent. The bulk of households receiving public assistance payments dropped from the food stamp program because of inability to purchase coupons. Most nonrecipients of public assistance left the program because income lifted them from eligibility. The large majority of low‐income households usually spent more for food than food stamps would have cost, but most households could not meet the program's regular participation requirement. Methods of increasing program participation are presented.
Impact of Food Chain Procurement Policies on the Fluid Milk Processing Industry
Authors: Gruebele James W. , Williams Sheldon W. , Fallert Richard F. 
Published: July 2006

AbstractThe growth of the food chains and the adoption of centralized milk programs, including the use of private‐label brands and their own processing facilities, has improved the bargaining position of food chains relative to fluid milk processors. Food retailer groups and milk processors were surveyed to determine the impact of changes in the retailing industry on the fluid milk processing industry. This article provides substantial groundwork for more detailed analysis of the performance aspects of both the food retailing and fluid milk processing industries that have resulted from the increasing vertical integration on the part of food retailers.
The Allocation and Pricing of Water in a River Basin
Authors: Guise J. W. B. , Flinn J. C. 
Published: July 2006

AbstractA spatio‐temporal equilibrium model that incorporates intraseasonal demands for irrigation water is developed for the situation with a (constrained) competitive market for water. An application of the quadratic programming model, which utilizes demand and supply estimates relating to an intensive irrigation area in southeastern Australia, is used to derive optimal short‐run allocation and pricing patterns for the resource. Extensions of the model to cover multiple dam river basins and additional water uses seem conceptually straightforward, but the limitations imposed by its deterministic partial equilibrium character should be recognized.
Agricultural Credit in Latin America: A Critical Review of External Funding Policy
Authors: Adams Dale W 
Published: July 2006

AbstractDuring the 1960's aid agencies channelled over one billion dollars to agricultural credit systems in Latin America. This plus local funds boosted the real value of rural credit by 12 percent per year. A number of assumptions underlying past credit policy are critically examined. It is argued that currently credit shortage is not the most pressing issue. Rather, emphasis should be placed on realistic pricing of rural credit and mobilizing rural savings for credit use through interest incentives.
A Dynamic Economic Model of Pasture and Range Investments
Authors: Burt Oscar R. 
Published: July 2006

AbstractThe traditional economic replacement problem is extended to accommodate a situation where quasi‐rents of future replacements are influenced by replacement age of the currently held asset. This generalized replacement model is applied to optimal timing of the clearing of brush and scrub timber from pasture and range. Dynamic programming is applied to the problem and the structure of the decision role analyzed. An approximately optimal decision rule is deduced by an analysis of the limiting behavior of the optimal policy. An illustrative example is given for pinyon‐juniper control in southwestern United States.
An Application of Statistical Decision Theory to Cattle Feedlot Marketing
Authors: Bullock J. Bruce , Logan Samuel H. 
Published: July 2006

AbstractThe commercial cattle feeder is continually faced with the decision of whether to market a particular lot of cattle at their current weight or to continue feeding them. Uncertainty about future price changes is an important factor in this decision. The study uses statistical decision theory to combine a priori information about the historical pattern of month‐to‐month price changes with information provided by a price forecasting model to develop monthly feed or sell decision criteria. These criteria specify the minimum predicted price change required to generate positive expected returns from feeding an additional 30 days.
Rates of Return for Farm Real Estate and Common Stock
Authors: Kost William E. 
Published: July 2006

AbstractThere has been considerable discussion in recent years concerning the income position of the agricultural sector of the economy. Investment analysts are generally pessimistic about investing in real estate—especially farm real estate. Since farm real estate and common stock are very similar, their rates of return take on added significance when these two assets are considered as investment alternatives. A model is presented by which comparable rates of return may be calculated. Income, price, and total rates of return are calculated for farm real estate and common stock for the 1950–1963 period. Rates of return on common stock are larger and show greater yearly fluctuation for this period.
Utility Analysis in a Practical Setting
Authors: Officer R. R. , Halter A. N. 
Published: July 2006

AbstractAn empirical study involving derivations of farmers' utility functions and the accuracy of these functions in predicting practical decisions is here reported. Three models of utility estimation which were used are compared as to their predictive accuracy and usefulness under field conditions. The study tests the hypothesis that maximizing expected utility, as a criterion of decision, is superior to maximizing expected monetary value. Utility functions are derived for two points in time in order to test the hypothesis that, if utility functions are to serve as a guide to the decision maker, they must be derived at each point in time at which decisions are made. Implications for decision‐making research and for practical farm decision making are indicated.
Estimates of Potential Effects of New Technology on Agriculture in Punjab, India
Authors: Mann K. S. , Moore C. V. , Johl S. S. 
Published: July 2006

AbstractNew high‐yielding varieties of crops are now available in developing countries. Their potential for improving food and fiber supplies is limited by the availability of inputs such as fertilizer, irrigation, and pesticides. The effects of present, projected, and nonrestrictive supplies of fertilizer are estimated for Punjab State, India. Results indicate that large amounts are needed over and above current plan targets in order to maximize food output and farm incomes. Further, changes in price policy will be necessary to maintain production of crops where no improved‐yield‐potential varieties are available. Uniform allocations of scarce fertilizer supplies within a state will not maximize agricultural production and incomes.