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Biomedical subjects

R G Cutler

Publications and source records attributed to R G Cutler.

8 recordsLinked to original sources
PubMed1979

Evolution of human longevity: a critical overview.

Evolution of longevity of the ungulates, carnivores and primates is reviewed. Special emphasis is focused on recent evolutionary history of longevity along the hominid ancestral-descendant sequence leading to modern man. Maximum life span potential (MLP) or the change in MLP is predicted in extinct species by (1) a phylogenetic analysis of the MLP of present living species and (2) an empirical equation using brain and body weight estimates from fossils. Both of these methods indicate MLP generally increased during mammalian evolution and at an extremely fast rate during the appearance of the hominid species. These results suggest that relatively few genetic alterations were necessary during the recent evolutionary history of man to significantly extend his innate ability to maintain mental and physical health. Much evidence indicates these genetic alterations principally involve regulatory genes, which control a conserved set of structural genes. Evolution of longevity in man could therefore be a result of simple changes in temporal and quantitative expression. Whether these genetic alterations result from mutational changes and/or chromosomal rearrangement cannot yet be evaluated.

Aging↗
PubMed1978

Age-dependent relaxation of gene repression: increase of endogenous murine leukemia virus-related and globin-related RNA in brain and liver of mice.

A progressive loss in the ability of cells to maintain their normal specialized states of differentiation could be the common denominator underlying much of the physiology and pathology associated with the mammalian aging process. We investigated this possibility by searching for an age-dependent derepression of endogenous genes in tissues in which they are not normally expected to be expressed. Complementary DNA (cDNA) probes to globin genes and to the murine leukemia type C RNA virus (MuLV) genome were used to detect the presence of RNA complementary to these genes in RNA extracted from brain and liver in young and old mice. Significant amounts of globin RNA were found in brain nuclei and cytoplasm. No age difference was found in the globin RNA sequences present, but the number of globin RNA molecules increased from about 15 in 6-month to 34 in 27-month-old animals for nuclei and 280 in 6-month to 500 in 27-month-old animals for cytoplasm. Similar results were found for liver. RNA complementary to the MuLV cDNA probe was also found but, in contrast to globin, the different RNA sequences increased in both brain and liver nuclei from about 45% of the MuLV genome in 6-month to 72% in 27-month-old animals. The number of MuLV-related RNA molecules remained constant at about 22 and 38 per nuclei for brain and liver, respectively. Derepression of genes of this magnitude could result in a time-dependent increase in virus-related diseases and a general deterioration of the organism.

Aging↗
PubMed1978

Subcutaneous mastectomy in small, large, or ptotic breasts with immediate submuscular placement of implants.

We present a series of 70 patients who have had bilateral subcutaneous mastectomies with immediate placement of implants under the intact pectoralis major and upper part of the serratus anterior. Twenty-two of these patients have had a simultaneous mastopexy, with a free nipple graft. All 70 patients have both of their implants now (up to 3 years) and have a satisfactory appearance.

Breast↗
PubMed1975

Evolution of human longevity and the genetic complexity governing aging rate.

Genetic complexity of processes governing the aging rate of man was estimated by determining the maximum rate lifespan has evolved along the hominid ancestral-descendant sequence. Maximum lifespan potential was found to have increased approximately 2-fold over the past 3 million years, reaching a maximum rate of increase of 14 years per 100,000 years about 100,000 years ago. It is estimated that about 0.6% of the total functional genes have received substitutions leading to one or more adaptive amino acid changes during this 100,000-year time-period. This suggests that aging is not the result of an expression of a large number of independently acting processes. Instead, primary aging processes appear to exist where only a few genetic changes are necessary to decrease uniformly the aging rate of many different physiological functions.

Aging↗