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PubMed2006

Kant on the history of nature: the ambiguous heritage of the critical philosophy for natural history.

This paper seeks to show Kant's importance for the formal distinction between descriptive natural history and a developmental history of nature that entered natural history discussions in the late eighteenth century. It is argued that he developed this distinction initially upon Buffon's distinctions of 'abstract' and 'physical' truths, and applied these initially in his distinction of 'varieties' from 'races' in anthropology. In the 1770s, Kant appears to have given theoretical preference to the 'history' of nature [Naturgeschichte] over 'description' of nature [Naturbeschreibung]. Following Kant's confrontations with Johann Herder and Georg Forster in the late 1780s, Kant weakened the epistemic status of the 'history of nature' and gave theoretical preference to 'description of nature'. As a result, Kant's successors, such as Goethe, could draw from Kant either a justification for a developmental history of nature, or, as this paper argues, a warrant from the critical philosophy for denying the validity of the developmental history of nature as anything more than a 'regulative' idea of reason.

History, 18th Century↗
PubMed1984

Life history of cells mediating natural resistance to tumor cells and bone-marrow transplants: the respective roles of cell lineage commitment and host environment in determining strain characteristics of natural resistance to foreign marrow grafts.

A class of cells present in the blood and lymphoid tissues of mammals produces rapid cytolysis of tumor cells on first contact. Abundant evidence suggests that such natural killer (NK) cells play a role in tumor immunosurveillance in vivo. A similarly prompt and spontaneous activity can cause the rejection of foreign marrow transplants. These phenomena are known collectively as natural resistance. The cells mediating natural resistance are lymphoid in morphology, but are neither T nor B lymphocytes. Kinetically, NK cells and cells mediating natural resistance to foreign marrow grafts are themselves nondividing but are rapidly renewed from radiosensitive proliferating precursors in the bone marrow. They appear to have no long-lived (memory) component. Newly formed NK cells have a short residence time in the spleen. Other general properties of the natural-resistance cell lineage, including strain variation, ontogeny, and cell phenotype, are reviewed in this article. The present study aimed to examine the respective roles of cell lineage commitment and of the host environment in determining strain characteristics of natural resistance to foreign marrow grafts. Chimeras produced by inoculating mice of a strain that normally has little or no natural resistance with bone marrow from adult mice of a highly resistant strain develop resistance to a third-party marrow allograft. Such chimeras do not develop the full rejection capacity of the high-resistance strain, however; and chimeras created by inoculating marrow from infant mice develop less resistance than those reconstituted by bone marrow from adult mice. The results demonstrate that the ability to reject foreign marrow grafts develops as an intrinsic property of the natural-resistance cell lineage. The host environment may provide an additional influence, however, particularly in the initial development of natural resistance in early postnatal life.

Animals↗
PubMed2006

Health and well-being naturally: 'contact with nature' in health promotion for targeted individuals, communities and populations.

ISSUE ADDRESSED: The increase in mental health disorders worldwide makes it important to recognise health promotion interventions that are effective, accessible and affordable. Although natural spaces are coming to be recognised as health-promoting settings for general populations, little is understood about the use of nature-contact in treatment and care for individuals experiencing ill-health. METHODS: This paper provides a summary of key research findings and presents a case study examining the self-reported health and well-being benefits of nature contact for a small clinical sample. The 'Spectrum of Interventions for Mental Health Problems and Mental Disorders' provides a conceptual framework for ordering current and future information relating to nature-based interventions. RESULTS: Evidence demonstrates that separately, physical activity, social connection, and contact with nature enhance human health and well-being. The case example illustrates how 'active', 'social' and 'adventurous' contact with nature may be combined within a treatment intervention to protect and enhance the health of individuals experiencing chronic mental, emotional and physical health difficulties. CONCLUSIONS: 'Contact with nature' constitutes a health promotion strategy with potential application in prevention, early intervention, treatment and care. Recommendations include further research to investigate the benefits of nature contact within existing interventions, and the impacts of 'active' and 'social' nature contact within tailored interventions for targeted individuals and communities.

Adolescent↗
PubMed2003

Wonderful secrets of nature. Natural knowledge and religious piety in Reformation Germany.

Sixteenth-century Germany witnessed a tremendous flourishing of vernacular literature. An unprecedented number and variety of texts were produced for new groups of readers. This essay analyzes one underexplored genre of this vernacular literature: texts on the natural world. Numerous books on animals, plants, minerals, and natural marvels rolled off the German presses in this period, indicating a widespread curiosity about the natural world. These texts give valuable insight into the views of nature available to a broad lay audience, literate in German but not necessarily in Latin. They reveal a pervasive sense of nature as divinely created and a deep conviction that contemplation of the natural world would lead to greater piety. The divine and the mundane were thoroughly intertwined in vernacular natural histories. While other historians of science have seen the sixteenth century as a period of increasingly secular ways of thinking about nature, I argue for the persistence, and even the intensification, of profoundly religious attitudes toward the natural world.

Animals↗
PubMed1995

Irreversible inhibition of human natural killer cell natural cytotoxicity by modification of the extracellular membrane by the adenine nucleotide analog 5'-p-(fluorosulfonyl)benzoyl adenosine.

Extracellular adenine nucleotides are inhibitors of the human natural killer cell line NK3.3 natural cytotoxicity activity. Natural cytotoxicity was inhibited approximately 26% by 1 mM ATP and 21% by 1 mM ADP. 5'-Adenylyl imidodiphosphate, a nonhydrolyzable ATP analog, inhibited natural cytotoxicity by 41% at a concentration of 1 mM and > 97% at a concentration of 10 mM. In contrast, AMP was not inhibitory. Adenosine was a weak inhibitor of natural cytotoxicity and may represent an alternate regulatory pathway. Removal of the nucleotides resulted in the restoration of control levels of natural cytotoxicity activity. The affinity label 5'-p-(fluorosulfonyl)benzoyladenosine (5'-FSBA) is a synthetic analog of ATP or ADP containing an electrophilic fluorosulfonyl group capable of covalently modifying proteins at adenine di- and triphosphate nucleotide-binding sites. Natural cytotoxicity was irreversibly inhibited by modification of the extracellular membrane of NK3.3 cells by 5'-FSBA. This inhibition was concentration dependent with an I50 approximately 100 microM and complete inhibition at 1 mM. Modification of NK3.3 by 5'-FSBA did not affect the formation of effector-target cell conjugates; however, granule release was inhibited. This targets the site of inhibition by 5'-FSBA modification to a pathway preceding granule release. Irreversible, covalent modification of surface adenine nucleotide-binding proteins by 5'-FSBA provides a probe to study the role of specific adenine nucleotide-binding proteins in the extracellular regulation of natural killer cytolytic activity by adenine nucleotides.

Adenosine↗
PubMed1996

Hemolytic anemia in chronic large granular lymphocytic leukemia of natural killer cells: cytotoxicity of natural killer cells against autologous red cells is associated with hemolysis.

BACKGROUND: It has ben suggested that natural killer cells are effectors in some hemolytic transfusion reactions, but a direct mechanism of the destruction of red cells has not been demonstrated. CASE REPORT: Lytic activity of natural killer cells against autologous red cells was found in a patient with large granular lymphocytic leukemia of natural killer cells and hemolytic anemia, with no evidence of immune antibody or complement-mediated hemolysis. Large granular lymphocytes in the blood showed a CD2+ CD3- CD16+ CD57+ phenotype, cytotoxic activity against natural killer cell-sensitive K562 target cells, and no lytic activity against natural killer cell-resistant JY target cells. Cytotoxicity directed against red cells was quantified by a 51Cr-specific release assay with autologous and ABO-identical red cells used as target cells and the patients purified natural killer cells used as effector cells in the presence and absence of autologous serum. The cytotoxic activity of natural killer cells was directed against autologous red cells but not against allogenic red cells, and it was not enhanced by the presence of autologous serum in the medium. Clinical remission was induced by the administration of cyclophosphamide, after which no evidence of cytotoxic activity against the red cells could be found. CONCLUSION: Hemolytic anemia in the presence of a negative direct antiglobulin test can be attributed to a direct cytotoxic mechanism mediated by natural killer cells.

Aged↗
PubMed2003

Natural killer cells in human peripheral blood and primary cutaneous natural killer cell lymphomas may express cutaneous lymphocyte antigen.

In normal human peripheral blood, cutaneous lymphocyte antigen is expressed by memory T cells, suggesting a specific tissue-homing population of T cells. In this study it is demonstrated that 6% of CD56 + natural killer cells in peripheral blood also express cutaneous lymphocyte antigen (CLA). It was also detected that most of the tumor cells in primary cutaneous nasal-type natural killer cell lymphomas were CLA-positive, whereas primary nasal natural killer cell lymphomas were CLA-negative. Although natural killer cells traditionally are known to be non-specific immune cells without antigen specificity and little is known about the role of natural killer cells in skin diseases, the results of this study suggest the existence of a subset of skin-associated CLA+ CD56+ natural killer cells. These natural killer cells may be related to the pathogenesis of primary cutaneous natural killer cell lymphomas.

Adolescent↗
PubMed1997

Functional role for Syk tyrosine kinase in natural killer cell-mediated natural cytotoxicity.

Natural killer (NK) cells are named based on their natural cytotoxic activity against a variety of target cells. However, the mechanisms by which sensitive targets activate killing have been difficult to study due to the lack of a prototypic NK cell triggering receptor. Pharmacologic evidence has implicated protein tyrosine kinases (PTKs) in natural killing; however, Lck-deficient, Fyn-deficient, and ZAP-70-deficient mice do not exhibit defects in natural killing despite demonstrable defects in T cell function. This discrepancy implies the involvement of other tyrosine kinases. Here, using combined biochemical, pharmacologic, and genetic approaches, we demonstrate a central role for the PTK Syk in natural cytotoxicity. Biochemical analyses indicate that Syk is tyrosine phosphorylated after stimulation with a panel of NK-sensitive target cells. Pharmacologic exposure to piceatannol, a known Syk family kinase inhibitor, inhibits natural cytotoxicity. In addition, gene transfer of dominant-negative forms of Syk to NK cells inhibits natural cytotoxicity. Furthermore, sensitive targets that are rendered NK-resistant by major histocompatibility complex (MHC) class I transfection no longer activate Syk. These data suggest that Syk activation is an early and requisite signaling event in the development of natural cytotoxicity directed against a variety of cellular targets.

Animals↗
PubMed1986

Augmentation of natural killer cytotoxicity by alpha or gamma natural and recombinant interferons and interferon inducers. Effect of monocytes.

We investigated the effect of human peripheral blood monocytes on the augmentation of natural killer cytotoxicity by alpha or gamma natural and recombinant interferons (IFN) and certain interferon inducers. We observed that: (1) in the majority of the donors examined (75%) human peripheral blood monocytes do not affect natural killer cytotoxicity, determined by a 4-hour chromium-51 release assay, against target cells from hemopoietic human tumor cell lines. (2) Monocytes are not required and do not affect the augmentation of natural killer cytotoxicity by Escherichia coli-derived IFN-gamma, natural human IFN-gamma, E. Coli-derived IFN-alpha 2 or natural human IFN-alpha. E. Coli-derived IFN-gamma and natural human IFN-gamma have been reported to activate monocyte cytotoxicity determined in 72-hour assay. (3) Monocytes are not required for the augmentation of natural killer cytotoxicity against target cells from hemopoietic tumor cell lines by polyinosinic acid-polycytidylic acid or staphylococcal enterotoxin A.

Cells, Cultured↗
PubMed2006

Gender expectations: natural bodies and natural births in the new midwifery in Canada.

In this article, I examine the meaning of natural bodies and natural births in contemporary midwifery in Canada and explore the impact of these central concepts on the embodied experiences of pregnant and birthing women. The ideal of a natural birth has been used as a successful rhetorical strategy in scholarly and popular feminist works on childbirth to counter and critique the predominant biomedical or "technocratic" model of the pregnant and birthing body as inherently problematic and potentially dangerous to the fetus. Contemporary Canadian midwifery--which only as recently as 1994 made a historic transition from a grassroots social movement to a full profession within the public health care system--continues to work discursively through the idiom of nature to affect women's knowledge and experience of their bodies and selves in pregnancy and birth. However, my key finding in this ethnographic study, which focused primarily on midwifery in the province of Ontario in the years following professionalization, is that natural birth is being redefined by the personal, political, and pragmatic choices of midwives and their clients. I argue that the construction, negotiation, and experience of natural birth in contemporary midwifery both reflects and promotes a fundamental shift away from essentialized understandings as it makes room for biomedical technology and hospital spaces, underpinned by the midwifery logics of caring and choice. Natural birth in this context also carries important cultural messages--gender expectations--that posit women as persons and bodies as naturally competent and knowing.

Anthropology, Cultural↗
PubMed1996

[Natural or artificial surfactants? Arguments in favour of natural surfactants].

The use of exogenous surfactant (ES) is an essential component for prevention and treatment of hyaline membrane disease (HMD). The ES available for clinical use are of two therapeutic classes: natural surfactants prepared from mammalian lung and artificial surfactants. The choice between these two classes of ES is controversial. In this overview, we present the arguments in favour of the preferential use of natural ES. The presence of hydrophobic specific proteins (SP-B and SP-C) provides to natural ES better surface tension properties than artificial ES. The in vitro greater efficacy of natural ES has been confirmed in vivo in experimental models of surfactant deficiency, human pharmacodynamic studies, and comparative clinical trials. Furthermore, the excellent clinical tolerance and harmlessness of natural ES has been firmly established. A meta-analysis of the comparative clinical trials between natural ES and one artificial ES (enrolling as many as 4400 babies treated for HMD) suggests that the use of natural ES compared to this artificial ES significantly reduces the neonatal mortality by 20%. In conclusion, all these arguments are in favor of the preferential use of natural ES for prevention and treatment of HMD.

Animals↗
PubMed2001

The natural history of renal disease in Australian Aborigines. Part 2. Albuminuria predicts natural death and renal failure.

BACKGROUND: The purpose of this study was to describe the relationship of albuminuria and glomerular filtration rate (GFR) with natural death and renal failure in an Australian Aboriginal community with high rates of renal disease. METHODS: Study subjects were 825 adults (18+ years, mean 33.6 years) or 88% of adults in a remote community who participated in a health screening program offered between 1990 and 1997. The urinary albumin:creatinine ratio (ACR; g/mol) was used as the renal disease marker. Participants were followed for 1.0 to 9.8 years (mean 5.8 years) until renal failure, death, the start of systematic antihypertensive/renal-protective treatment or June 30, 2000. RESULTS: Sixty-five people reached a terminal end point of renal failure or natural death. Sixteen people developed terminal renal failure, all of whom had an ACR of 34+ at baseline exam. There were 49 other natural deaths, which were also strongly correlated with increasing ACR and decreasing GFR over a wide range. This was observed in people without diabetes and in people with normal and elevated blood pressures. It applied to deaths associated with cardiovascular disease and to deaths without an assigned primary or underlying cardiovascular or renal cause. With adjustment for age, the association with death was more robust with ACR than GFR. When compared with people with an ACR <3.4, the hazard ratio (HR; 95% CI) for nonrenal natural death of persons with an ACR 3.4 to 33 was 3.0 (1.1 to 8.4), with an ACR 34 to 99, it was 5.4 (1.8 to 15.9), and with an ACR 100+, it was 6.5 (2.0 to 21). Regression equations predicted that each tenfold increase in the ACR was associated with a 3.7-fold increase in all-cause natural death: a> 400-fold increase in renal deaths, a 4-fold increase in cardiovascular deaths, and a 2.2-fold increase in nonrenal noncardiovascular deaths. Eighty-four percent of all-cause natural death was associated with pathologic albuminuria. CONCLUSION: All renal failure develops out of a background of persistent albuminuria in this population. More important, albuminuria and, inversely, GFR are powerful markers of risk for nonrenal natural death, including, but not restricted to, cardiovascular deaths. Most of the risk for premature death can be assessed by a simple urine test, and interventions that prevent development and progression of albuminuria and loss of GFR should not only prevent renal insufficiency, but powerfully reduce mortality from natural causes as well.

Adult↗
PubMed2006

Spillover edge effects: the dispersal of agriculturally subsidized insect natural enemies into adjacent natural habitats.

The cross-edge spillover of subsidized predators from anthropogenic to natural habitats is an important process affecting wildlife, especially bird, populations in fragmented landscapes. However, the importance of the spillover of insect natural enemies from agricultural to natural habitats is unknown, despite the abundance of studies examining movement in the opposite direction. Here, we synthesize studies from various ecological sub-disciplines to suggest that spillover of agriculturally subsidized insect natural enemies may be an important process affecting prey populations in natural habitat fragments. This contention is based on (1) the ubiquity of agricultural-natural edges in human dominated landscapes; (2) the substantial literature illustrating that crop and natural habitats share important insect predators; and (3) the clear importance of the landscape matrix, specifically distance to ecological edges, in influencing predator impacts in agroecosystems. Further support emerges from theory on the importance of cross-boundary subsidies for within site consumer-resource dynamics. In particular, high productivity and temporally variable resource abundance in agricultural systems are predicted to result in strong spillover effects. More empirical work examining the prevalence and significance of such natural enemy spillover will be critical to a broader understanding of fragmentation impacts on insect predator-prey interactions.

Agriculture↗
PubMed1985

Anticancer activity of a natural product, viva-natural, extracted from Undaria pinnantifida on intraperitoneally implanted Lewis lung carcinoma.

A natural product, named Viva-Natural, extracted from a dietary seaweed Undaria pinnantifida has been found to be therapeutically active against Lewis lung carcinoma (LLC). Viva-Natural also demonstrated moderate prophylactic activity against LLC in allogeneic mice. The active principle(s) which was concentrated in the water-insoluble fraction of Viva-Natural was essentially noncytotoxic in KB cell cultures, and probably a polysaccharide. Viva-Natural was found to be significantly effective in enhancing the natural cytolytic activity of peritoneal macrophages against KB cells as targets in in vitro assay, suggesting that the antitumor action of Viva-Natural might be indirect through the activation of nonspecific immune systems. A combination therapy of Viva-Natural and standard anticancer drugs was additively or synergistically effective.

Animals↗
PubMed1992

[Chemical investigation of naturally occurring drug materials. Elucidation of scientific basis for traditional medicines and exploitation of new naturally occurring drugs].

In search of new biologically active compounds in nature, we have been investigating naturally occurring substances on the following subjects: I. chemical studies on naturally occurring drug materials [a) elucidation of bioactive constituents in natural drugs, b) elucidation of scientific basis for crude drug processing, and c) investigation of bioactive constituents in food materials], II. exploitation of new pharmaceuticals in nature [a) investigation of marine natural products and b) exploitation of Indonesian medicinal plants], and III. synthetic studies on bioactive natural products [a) chemical modification of naturally abundant carbohydrates and terpenoids and b) synthetic studies of complex lipids]. This article reviews the results obtained in our laboratory since 1978 on the subjects of I-a, b, c, II-a, and III-a.

Alkaloids↗