[Sustainable development: a contradiction]. / Crecimiento sostenible: una incongruencia.

PIP: Economists are very much interested in theories of impossibility, especially in those that demonstrate that it is impossible for the world economy to increase to the point of solving poverty and the environmental degradation. In its physical aspects, the economy is an open subsystem of the terrestrial ecosystem, which is finite in material resources. As the economic subsystem grows, it incorporates an increasing proportion of the total ecosystem. For this reason, development is not sustainable. The term sustainable development, as it applies to the economy, is a contradiction. The economists claim that the growth of the gross national product is a combination of quantitative and qualitative increase and is not subject to the laws of physics. They are right to some degree, because growth means natural material increase by assimilating accretion, while development denotes expansion to slowly realize the opportunities for a state of conditions that are more, bigger, or better. When something grows, size increases. However, when something develops, different things happen. The terrestrial ecosystem develops but does not grow. Its subsystem, the economy, can continue to develop. Thus, sustainable development means development without growth, qualitative improvement which maintains the interchange of material-energy found within regenerative capacities of the ecosystem. In fact, the term sustainable development utilizes as a synonym the contradiction of sustainable growth. Politically, it is very difficult to admit that growth has its limits. The earth will not tolerate the multiplication of grain harvests 64 times only because in the last centuries a culture has developed that depends on exponential growth for its economic stability. The growth of agricultural plants is not sustainable. For plants there is a limit that the earth can support, as there is a limit for humans and cars, with dire consequences for those who ignore this fact.^ieng

A Marxian-Malthusian view of poverty and development.

Abstract The names of Marx and Malthus are often linked in disjunction but never in conjunction. Nevertheless, the thesis argued in this paper is that the two historically dominant theories of poverty, the Marxian and the Malthusian, are not inconsistent, but complementary; that a union of the two yields a basic fourfold typology of social classes by differential ownership of property and differential fertility; that this typology can also be viewed as a way of disaggregating the meaningless average of 'GNP per head' in a way which gives social content (i.e. a distributional dimension) to the concept; that the typology provides more satisfactory definitions of 'development' and 'overpopulation'; and that these four categories are improved, or usefully supplemented, by replacing the flowof income by the stock of wealth in each case. Also the universality of the typology is discussed along with some preliminary empirical considerations.

A forum: how big is the population factor?

PIP: 6 protagonists responded to the issue of population growth and its likely ramifications: Nafis Sadik, Ben J. Wattenberg, Herman E. Daily, Barry Commoner, James T. McHugh, and Karan Singh. Sadik stated that at the current rate of growth the world's population could double in 40 years. In 1990 the total reached 5.3 billion with the addition of another 92 million people that year. At this rate the number could reach 6.25 billion by 2000, 8.5 billion by 2025, and 10-11 billion before leveling off around 2085 with 96% of this growth in the developing countries. The African rate of growth of 3-4% cancels out development programs. The present signs of environmental stress include the impairment of the ozone layer, acidification, depletion of rain forests, and erosion. According to Wattenberg the problem is not population, it is culture, what people do that makes the difference. In south Korea, Indonesia, India, China, Brazil, and Mexico there have been major decreased in fertility since the early 1960s. Free market opportunities with family planning offer the solution. Daly opined that affluence was the main environment problem. Poverty induces higher fertility and environmental degradation; the specter of the consumption level of the average Indian rising to the levels of the average Swede looms; thus the consumption of industrial countries must be reduced. Commoner declared that the demographic transition as it had occurred in developed countries explains population growth as a result of improved living conditions and reduced mortality before fertility plummets because of even higher living standards. The economies of developing countries must be strengthened to eliminate poverty whereby they can attain stable populations. Cooperation among nations, enhancement of human life and dignity, and intensified efforts to provide family planning were advocated by the others.^ieng

Bleomycin induces strain-dependent alterations in the pattern of epithelial cell-specific marker expression in mouse lung.

Clinical use of the antineoplastic agent bleomycin is restricted due to pulmonary toxicity. Murine models of bleomycin-induced pulmonary fibrosis have been developed in an attempt to understand the mechanisms involved in the fibrotic process. Studies have shown that the alveolar epithelium is damaged early after bleomycin treatment. The purpose of this study was to evaluate the pattern of gene expression in airway and alveolar epithelial cells after bleomycin exposure in mice that vary in susceptibility to bleomycin-induced fibrosis. Surfactant protein C (SPC) and Clara cell-specific protein (CC10) mRNA were used as cell-specific markers of alveolar type II cells and airway Clara cells, respectively. Mice were treated with a single intratracheal dose of bleomycin and the pattern of SPC and CC10 transcripts was examined by in situ hybridization. The pattern of SPC mRNA 28 days after treatment was uniform in controls and resistant mice but exhibited a patchy appearance in sensitive mice. Bleomycin treatment also resulted in a strain-dependent loss of CC10 mRNA-expressing cells. In sensitive mice 28 days after treatment, SPC mRNA was ectopically expressed in the distal bronchiolar epithelium in a morphologically distinct cell type. Serial sections revealed that these cells either coexpressed CC10 mRNA or were located adjacent to CC10 mRNA-containing cells. This unique cell population may represent a progenitor cell type important in epithelial repair. The strain-dependent changes in CC10 and SPC gene expression after bleomycin treatment are suggestive of a role for the epithelium in pulmonary fibrosis versus repair.

Cell-specific gene expression reveals changes in epithelial cell populations after bleomycin treatment.

Epithelial repair following acute lung injury involves proliferation and differentiation of existing Clara cells and type II cells. Other mechanisms of epithelial repair may be involved in particularly severe cases. We used epithelial cell-specific markers to examine changes in the mouse lung epithelium 28 days after bleomycin treatment. The spatial distribution of surfactant proteins A, B, C (SPA, SPB, SPC), and Clara cell-specific protein (CC10) mRNA was compared by in situ hybridization in serial lung sections. CC10 mRNA-containing airway cells were replaced in many areas by SPB mRNA-expressing, ciliated cells that did not contain CC10 mRNA. In distal airway regions, we observed a subpopulation of epithelial cells that appeared to express SPA, SPB, SPC, and CC10 mRNA, and speculated that they may represent a multipotential stem cell population. These cells were found in focal clusters, which suggests that they expanded from a common cell. CC10 mRNA-containing cells were seen in alveolar-like structures thought to be the result of Clara cell migration or outpocketing. Our data suggest that there are repair mechanisms involved in epithelial repair after severe injury that have not previously been described.