The remarkable improvements in survival at older ages.

The belief that old-age mortality is intractable remains deeply held by many people. Remarkable progress, however, has been made since 1950, and especially since 1970, in substantially improving survival at older ages, even the most advanced ages. The pace of mortality improvement at older ages continues to be particularly rapid in Japan, even though mortality levels in Japan are lower than elsewhere. The progress in improving survival has accelerated the growth of the population of older people and has advanced the frontier of human survival substantially beyond the extremes of longevity attained in pre-industrial times. Little, however, is known about why mortality among the oldest-old has been so plastic since 1950. The little that is known has largely been learned within the past few years. New findings, especially concerning genetic factors that influence longevity, are emerging at accelerating rate.     

Phyletic Gradualism versus Punctuated Equilibria: Why case histories do not suffice

Many attempts have been made at supporting either one of the allegedly complementary divergence models Phyletic Gradualism (PG) and Punctuated Equilibria (PE) by patterns found in specific fossil sequences. However, assessing each model's connection with reality via such “individual case histories” appears not to constitute a relevant approach. Instead, in order to correctly establish the possible merits of both concepts, the claims of each have to be verified against general evolutionary theory. This is being pointed out herein by analyzing cladogenesis at the specific level as an example. [Phyletic Gradualism; Punctuated Equilibria; evolutionary theory; divergence models; case histories; additive speciation.]     

Effect of injectable or inhalational anesthetics and of neuroleptic, neuroleptanalgesic, and sedative agents on tumor blood flow

Among other parameters, varying blood flow values may be responsible for tumor-to-tumor variabilities in the radiobiologically hypoxic cell fraction of experimental rodent tumors. To test whether changes in tumor blood flow may be caused by anesthetic agents often used in radiobiology, the effect of injectable and inhalational anesthetics and of neuroleptic, neuroleptanalgesic, and sedative agents on blood flow in subcutaneous DS-carcinosarcomas implanted in Sprague-Dawley rats has been investigated using the 85Kr clearance technique. In conscious rats, 20-100 min after animal instrumentation mean blood flow is 0.62 +/- 0.17 ml/g/min (mean +/- SD) in 0.75 +/- 0.15 g tumors at a mean arterial blood pressure of 125 +/- 12 mm Hg. In animals receiving thiobutabarbital, chloral hydrate, or methoxyflurane tumor blood flow is somewhat higher than that measured in conscious rats. Tumor blood flow in animals receiving etomidate, ketamine-xylazine, fentanyl-fluanisone, or urethane is significantly lower than that in the thiobutabarbital group and somewhat lower than in the conscious animals. Blood flow values observed with midazolam, ketamine-midazolam, fentanyl-droperidol, droperidol, diazepam, and pentobarbital are similar to those measured in conscious rats. Virtually no flow alterations with time are detectable in conscious rats and with most of the drugs used. In animals anesthetized with urethane or methoxyflurane, tumor blood flow increases and tumor vascular resistance diminishes slightly with time.     

Untangling genetic influences on smoking,body mass index and longevity: a multivariate study of 2464 Danish twins followed for 28 years

A multivariate twin study was conducted in order to evaluate to what extent smoking, BMI and longevity are influenced by common genetic factors. The study was based on a 28-year follow-up of a sample of 2464 Danish twins who were born in the period 1890–1920 and who answered a questionnaire, including requests for information on smoking status, height and weight, in 1966. By 1994, approximately 2/3 of the sample had died. To compensate for the right-censoring, age at death was imputed for twins who were still alive by using survival analysis; all living subjects were more than 73 years old (mean 80 years, SD 5) in 1994. Proportions of covariance resulting from genetic and environmental factors in common and unique to the three traits were estimated from covariance matrices using the structural equation model approach. The study found no evidence for a substantial impact of common genetic factors on smoking, BMI and longevity. This suggests that only a small fraction of the genetic influences on longevity is mediated via a genetic influence on smoking and BMI and, furthermore, that it is unlikely that the associations between smoking and mortality and between BMI and mortality are confounded by common genetic factors. Received: 20 May 1996 / Revised: 21 May 1996     

Microbial coal desulphurization: calculation of costs

The sulphur found in coal is either part of the molecular structure, is contained in minerals such as pyrite (FeS₂), or occurs in minor quantities in the form of sulfate. When pyrite crystals are finely distributed within the coal matrix, mechanical cleaning can only remove part of the pyrite. It can, however, be removed by microbial action requiring only mild reaction conditions. The process involves simple equipment, almost no chemicals, but relatively long reaction times and, eventually, disposal of dissolved iron sulfate. Investment and operating costs are estimated for different process configurations on an industrial scale.     

Quantitative comparisons ofin situ microbial biodiversity by signature biomarker analysis

Microscopic examinations have convinced microbial ecologists that the culturable microbes recovered from environmental samples represent a tiny proportion of the extant microbiota. Methods for recovery and enzymatic amplification of nucleic acids from environmental samples have shown that a huge diversity existsin situ, far exceeding any expectations which were based on direct microscopy. It is now theoretically possible to extract, amplify and sequence all the nucleic acids from a community and thereby gain a comprehensive measure of the diversity as well as some insights into the phylogeny of the various elements within this community. Unfortunately, this analysis becomes economically prohibitive if applied to the multitude of niches in a single biome let alone to a diverse set of environments. It is also difficult to utilize PCR amplification on nucleic acids from some biomes because of coextracting enzymatic inhibitors. Signature biomarker analysis which potentially combines gene probe and lipid analysis on the same sample, can serve as a complement to massive environmental genome analysis in providing quantitative comparisons between microniches in the biome under study. This analysis can also give indications of the magnitude of differences in biodiversity in the blome as well as provide insight into the phenotypic activities of each community in a rapid and cost-effective manner. Applications of signature lipid biomarker analysis to define quantitatively the microbial viable biomass of portions of an Eastern USA deciduous forest, are presented.     

Punctuated equilibria and phyletic gradualism: Even partners can be good friends

The allegedly alternative theories of Phyletic Gradualism and Punctuated Equilibria are examined as regards the nature of their differences. The explanatory value of both models is determined by establishing their actual connection with reality. It is concluded that they are to be considered complementary rather than mutually exclusive at all levels of infraspecific, specific, and supraspecific evolution. So, in order to be described comprehensively, the pathways of evolution require at least two distinct models, each based on a discrete range of real phenomena. [Phyletic Gradualism; Punctuated Equilibria; evolutionary theories; divergence models; additive speciation; microevolution; macroevolution; anagenesis.]     

Randomized study on the treatment of chronic myeloid leukemia (CML) in chronic phase with busulfan versus hydroxyurea versus interferon-alpha

For palliative therapy during the chronic phase of CML busulfan has proved to be the drug of choice. During the past years hydroxyurea and also interferon-alpha have gained increasing significance since they might prolong the duration of the chronic phase. In a multicenter study it is being determined, whether the use of hydroxyurea or of interferon-alpha instead of busulfan prolongs the duration of the chronic phase of Philadelphia positive CML. Additional goals are the examination of whether the types of disease evolution and the terminal phases differ between the treatment groups, and the prospective recognition of prognostic criteria for the duration of the chronic phase of CML. By December 31, 1987, 326 CML-patients had been randomized, 150 for busulfan, 150 for hydroxyurea and 26 for interferon-alpha. The average age is 50 years. 59 patients reached the end of the chronic phase, 55 died. The mean observation time of all patients is 1.34 years. At present no significant difference in survival is recognizable between the busulfan and hydroxyurea groups. Fewer adverse effects have been observed in the hydroxyurea group. Philadelphia chromosome negative patients show a higher average age and tend to have lower white blood cell and platelet counts. The number of patients having received interferon-alpha is still too small to allow evaluation. This report intends to document organization and progress of this study which to our knowledge is, at present, the largest ongoing prospective multicenter study on the therapy of CML.