Biomedical subjects
N Myers
Publications and source records attributed to N Myers.
Population post-Rio.
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Political non-speak. Gadfly: Norman Myers.
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A population policy for the North?
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Tropical forests: present status and future outlook.
Tropical forests still cover almost 8 million km squared of the humid tropics but they are being destroyed at ever-more rapid rates. In 1989, the area deforested amounted to 142,200 km squared, or nearly 90% more than in 1979. Thus, whereas the 1989 amounted total to 1.8% of the remaining biome, the proportion could well continue to rise for the foreseeable future, until there is little forest in just a few decades. Deforestati on patterns are far from even throughout the biome. In much of the Southeast and Southern Asia, East and West Africa, and Central America, there is likely to be little forest left by the year 2000 or shortly thereafter. But in the Zaire basin, western Brazilian Amazonia, and the Guyana highlands, sizeable expanses of forest could persist a good while longer. The main agent of deforestation in the 'shifted cultivator' or displaced peasant, who, responding to land hunger and general lack of rural development in traditional farming areas of countries concerned, feels there is no alternative but to adopt a slash-and-burn lifestyle in forestlands. This person is now accounting for at least 60% of deforestation, a rapidly expanding proportion. However, he receives far less policy attention than the commercial logger, the cattle rancher, and other agents of deforestation.
Cigarette smoking, blast crisis, and survival in chronic myeloid leukemia.
We reviewed the records of all patients with chronic myeloid leukemia (CML) seen in the CML Clinic of the University of Colorado Health Sciences Center between 1968 and 1987 for a history of cigarette smoking. Patients who smoked for five or more pack/years within the ten years preceding, or after the diagnosis of CML, were defined as smokers. Adequate smoking histories were obtained on 122 patients. Eighty-seven of these were non-smokers and 35 were smokers by the above criteria. The smoking group had a higher predominance of males, an older median age, and were diagnosed earlier in the course of the 20 year study. Seventy-two patients had died at the time of analysis. All but one, a non-smoker, died from the development of blast crisis. The overall median actuarial survival was significantly reduced for smokers (35 months) as compared to non-smokers (47 months). This was particularly striking for patients who had succumbed to the disease, with a median survival of 30 months in smokers versus 46 months in non-smokers. Although various explanations could explain the differences noted, we conclude that cigarette smoking has an adverse effect on the development of blast crisis and survival in chronic myeloid leukemia.
The biodiversity challenge: expanded hot-spots analysis.
This paper aims to throw light on the mass extinction that is overtaking Earth's species. Using an analytic methodology developed for an earlier partial assessment, it focuses on a series of "hotspot" areas, these being areas that a) feature exceptional concentrations of species with high levels of endemism and b) face exceptional threats of destruction. The paper identifies another 8 such areas, 4 of them in tropical forests and 4 in Mediterranean-type zones. The analysis reveals that the 4 tropical-forest areas contain at least 2835 endemic plant species in 18,700 sq. km, or 1.1% of Earth's plant species in 0.013% of Earth's land surface; and that the 4 Mediterranean-type areas contain 12,720 endemic plant species in 435,700 sq. km, or 5.1% of Earth's plant species in 0.3% of the Earth's land surface. Taken together, these 8 hotspot areas contain 15,555 endemic plant species in 454,400 sq. km, or 6.2% of Earth's plant species in 0.3% of Earth's land surface. This is to be compared with the earlier hotspot analysis of 10 tropical-forest areas, with 34,400 endemic plant species in 292,00 sq. km, or 13.8% of Earth's plant species in 0.2% of Earth's land surface. Taking all 18 hot-spot areas together, the authors find they support 49,995 endemic plant species, or 20% of Earth's plant species, in 746,400 sq. km, or 0.5% of Earth's land surface. This means that one-fifth of Earth's plant species are confined to 0.5% of the Earth's land surface--and they occur in habitats that are mostly threatened with imminent destruction. By concentrating on these hotspot areas where needs are greatest and where the pay-off from safeguard measures would be greatest, conservationists can engage in a more systematized response to the challenge of large-scale impending extinctions.
Threatened biotas: "hot spots" in tropical forests.
The mass-extinction episode underway is largely centered on tropical forests, insofar as they contain at least half of all Earth's species and they are being depleted faster than any other biome. But species distributions and depletion patterns are anything but uniform throughout the biome. This paper identifies 10 areas that a) are characterized by exceptional concentrations of species with high levels of endemism and b) are experiencing unusually rapid rates of depletion. While these "hotspot" areas comprise less than 3.5% of remaining primary forests, they harbor over 34,000 endemic plant species (27% of all plant species in tropical forests and 13% of all plant species worldwide). They also feature 700,000 endemic animal species and possibly several times more. Unfortunately, they appear likely to lose 90% of their forest cover as soon as the end of the century or shortly thereafter, causing the extinction of almost 7% of Earth's plant species and at least a similar proportion of animal species, this occurring in only 0.2% of Earth's land surface. By concentrating on such areas where needs are greatest and where the pay-off from safeguard measures would also be greatest, conservationists can engage in a more systematized response to the challenge of large-scale extinctions impending in tropical forests.
Inhalation of iodine in the operating theatre.
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Latex-agglutination test for rubella antibody: validity of positive results assessed by response to immunization and comparison with other tests.
A commercial-latex agglutination (LA) assay ( Rubascan , Hynson , Westcott and Dunning, Baltimore, Md) performed on undiluted serum may be more sensitive than is the standard hemagglutination-inhibition assay for the detection of rubella antibody. To investigate whether a positive result of an LA test on undiluted serum was correlated with rubella immunity, we identified 29 persons whose sera produced negative results when initially tested by LA at a 1:10 dilution; 15 of these sera produced positive results and 14 produced negative results when retested undiluted. The immune status of each person for rubella was determined with a test for IgM rubella antibody on serum samples obtained three to five weeks after rubella immunization. None of the 15 persons whose preimmunization sera produced positive results by LA when tested undiluted developed IgM rubella antibody, as compared with 10 of the 14 persons whose preimmunization sera produced negative results (P less than 0.001). Data from this study support the specificity of a positive result of an LA test performed on undiluted serum, but a 1:5 dilution may be optimal for determination of rubella immune status.
Training helps staff warm up to computers.
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Hemodynamic findings in 123 patients with acute myocardial infarction on admission.
Hemodynamic and clinical evaluations of 123 patients with acute myocardial infarction were performed during the first hour of admission to the hospital. In the 123 patients, the right atrial pressure was less than 10 mm Hg in 49 patients, the right atrial oxygen saturation was less than 70% in 97 patients, the arteriovenous oxygen difference was greater than 5.0 vol% in 78 patients. The arterial Po2 was less than 90 mm Hg in 101 of 107 patients who could be evaluated while breathing room air. The cardiac index was depressed below 3.0 L/min/m2 in 65 of 98 patients. The hemodynamic findings generally correlated with the clinical status of the patient; however, within each clinical class of patients there was a wide spectrum of values for each measurement evaluated. There was also considerable overlap of the values found within each clinical classification. It is concluded that hemodynamic evaluation of patients with acute myocardial infarction presents a profile of the patient which is frequently different from the profile that clinical evaluation presents. An objective hemodynamic classification of patients with acute myocardial infarction may provide a more useful index for the evaluation of the patient's prognosis and for the assessment of preventative therapy.
Enhancing accreditation visits with application sketches.
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Nutritional and metabolic characterization of a thiamine-deficient rat model.
The effects of a thiamine-deficient diet on plasma and tissue vitamin concentrations and on whole-body glucose metabolism were assessed. Male Sprague-Dawley rats (175 to 200 g body weight) fed a thiamine-deficient (TD) or nutritionally complete purified diet were used for plasma thiamine mononitrate and monophosphate and for red blood cell and tissue thiamine pyrophosphate (TPP) determinations weekly for up to 5 weeks. Additional rats were used for assessment of basal glucose kinetics by using a primed constant infusion of [3-3H]glucose. Plasma thiamine mononitrate levels decreased 60% at 1 week and were undetectable after 5 weeks on the diet. Plasma thiamine monophosphate decreased 80% after 1 week on the TD diet, and levels were undetectable after 4 weeks on the diet. Red blood cell TPP in the TD group decreased progressively with time: 54% at 1 week, 86% at 3 weeks, and 92% at 5 weeks. At 1 and 4 weeks, the decrease in tissue TPP was significant in the liver (65% and 89%, respectively), gut (52% and 94%, respectively), spleen (40% and 60%, respectively), and skeletal muscle (37% and 76%, respectively), with the brain (7% and 84%, respectively) showing the slowest initial rate of depletion. The TD diet did not alter plasma glucose concentrations, but it increased plasma lactate by 75% and plasma pyruvate by 50% to 75%. Rates of hepatic glucose production and peripheral glucose utilization were not different between the control and TD rats at 2 weeks, but they were 25% higher in the TD rats after 6 weeks on the diet.(ABSTRACT TRUNCATED AT 250 WORDS)
Precaution: belief, regulatory system, and overarching principle.
The precautionary principle has been incorporated as a belief statement in international agreements for more than a decade. The 1998 Wingspread definition of the principle was the first to bring together four components that, in the past two years, have formed the elements of a broader, overarching approach to precaution that is a robust basis for its specific implementation: prompt action even in the face of scientific uncertainty, burden of proof and persuasion on proponents of potentially hazardous technologies, assessment of alternatives, and transparency. This broad approach to precaution is in direct conflict with the simplistic, easily manipulated principles and methods of risk-assessment-based risk management being exported by U.S. officialdom. In contrast to risk assessment, precaution, broadly defined, incorporates the full range of human intelligence in the task of protecting human health and the environment: flexibility, foresight, fairness, thoughtful consideration, and honesty.
Scientists reinforce population control policies.
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