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Biomedical subjects

A C Wilson

Publications and source records attributed to A C Wilson.

At least 271 records · Page 15Linked to original sources
PubMed1969

Phenoxyethanol: protein preservative for taxonomists.

Pieces of chicken heart or skeletal muscle were placed in a dilute solution of the antimicrobial agent 2-phenoxyethanol and stored at room temperature. Under these conditions, the serum albumin, lactate dehydrogenase, and malate dehydrogenase in these tissues survived in easily detectable amounts for at least 2 weeks. The surviving proteins appeared to be identical with those of fresh tissues in physical, catalytic, and immunological properties. Phenoxyethanol also preserved heart and muscle proteins of representatives of other vertebrate classes. Tissue samples collected in the analysis by biochemical taxonomists.

Animals↗
PubMed1969

A molecular time scale for human evolution.

We discuss published molecular evidence concerning the relationship of man to African apes and Old World monkeys. Quantitative comparisons of their serum albumins, transferrins, hemoglobins, and DNA show that man is genetically much more similar to the African apes than to the Old World monkeys. The amino acid sequences of hemoglobins from humans, chimpanzees, gorillas, and rhesus monkeys are consistent with the hypothesis that the probability of an amino acid substitution occurring in a given interval of time is the same for every hemoglobin lineage. This allows the use of these data as a hemoglobin evolutionary clock, just as we have previously done with the albumins. It is shown that concordance exists between the hemoglobin and albumin results and that both support the suggestion that the human lineage diverged from that leading to the African apes far more recently than is generally supposed. Considering both the albumin and hemoglobin data, we would set the most probable date at 4 to 5 million years.

Amino Acid Sequence↗
PubMed1967

Immunological time scale for hominid evolution.

Several workers have observed that there is an extremely close immunological resemblance between the serum albumins of apes and man. Our studies with the quantitative micro-complement fixation method confirm this observation. To explain the closeness of the resemblance, previous workers suggested that there has been a slowing down of albumin evolution since the time of divergence of apes and man. Recent evidence, however, indicates that the albumin molecule has evolved at a steady rate. Hence, we suggest that apes and man have a more recent common ancestry than is usually supposed. Our calculations lead to the suggestion that, if man and Old World monkeys last shared a common ancestor 30 million years ago, then man and African apes shared a common ancestor 5 million years ago, that is, in the Pliocene era.

Animals↗
PubMed1967

Molecular size of hagfish muscle lactate dehydrogenase.

In contrast to an earlier report, we find that the primitive vertebrate Eptatretus possesses a muscle lactate dehydrogenase whose molecular size is like that of lactate dehydrogenases from higher vertebrates. The molecular size of lactate dehydrogenase appears to have remained constant during evolution.

Animals↗
PubMed1967

Enzymatic identification of fish products.

Comparative enzymological techniques were used to distinguish between the muscle lactate dehydrogenases of 26 fish species. Intergeneric differences in enzymatic properties were frequently encountered. The techniques revealed, in addition, that some commercial samples of frozen fish fillets, labeled "haddock," contained cod lactate dehydrogenase.

Animals↗
PubMed1966

Quantitative immunochemistry and the evolution of primate albumins: micro-complement fixation.

Quantitative micro-complement fixation was used to compare human serum albumin with the serum albumins of apes, monkeys, and prosimians. The results are consistent with those obtained by other immunological techniques, and they are consistent with the accepted phylogenetic position of these groups. The method requires much less antigen and antibody is more sensitive to small differences in albumin structure. A large scale survey of species differences in protein structure is possible with less than a milliliter of antiserum.

Animals↗
PubMed1966

Evolution of malate dehydrogenase in birds.

Heart extracts from over 100 species of birds were subjected to starch-gel electrophoresis at pH 7. The "supernatant" form of malate dehydrogenase, an enzyme present in every extract, was then located on the gels by a specific staining method. The mobility of this enzyme shows very little interspecific variation. Nearly all birds tested have a supernatant malate dehydrogenase that moves as fast as the chicken enzyme. Those species with an enzyme of unusual mobility are of taxonomic interest. For example, hummingbirds and swifts, which are usually considered as two suborders of Apodiformes, are unique among the birds tested in having an enzyme that moves 63 percent as fast as the chicken enzyme. This finding appears to confirm the unity of the Apodiformes, an order whose unity has long been open to question. Similarly all families tested in the shorebird order (Charadriiformes) are unique in having an enzyme that moves 55 percent as fast as the chicken enzyme. The unity of this order was also previously open to question.

Animals↗
PubMed1966

Peafowl lactate dehydrogenase: problem of isoenzyme identification.

Peafowl, like other vertebrates, contain multiple forms of lactate dehydrogenase. The electrophoretic properties of the peafowl isoenzymes are unusual in that the isoenzyme from heart tissue can be either more or less anodic than that of muscle, depending on the pH. This finding focuses attention on the problem of isoenzyme identification. It is suggested that isoenzymes be identified on the basis of properties that are chemically and biologically more significant than electrophoretic mobility.

Animals↗
PubMedDate not supplied

Predictors and mediators of successful long-term withdrawal from antihypertensive medications. TONE Cooperative Research Group. Trial of Nonpharmacologic Interventions in the Elderly.

BACKGROUND: National guidelines recommend consideration of step down or withdrawal of medication in patients with well-controlled hypertension, but knowledge of factors that predict or mediate success in achieving this goal is limited. OBJECTIVE: To identify patient characteristics associated with success in controlling blood pressure (BP) after withdrawal of antihypertensive medication. DESIGN: The Trial of Nonpharmacologic Interventions in the Elderly tested whether lifestyle interventions designed to promote weight loss or a reduced intake of sodium, alone or in combination, provided satisfactory BP control among elderly patients (aged 60-80 years) with hypertension after withdrawal from antihypertensive drug therapy. Participants were observed for 15 to 36 months after attempted drug withdrawal. MAIN OUTCOME MEASURES: Trial end points were defined by (1) a sustained BP of 150/90 mm Hg or higher, (2) a clinical cardiovascular event, or (3) a decision by participants or their personal physicians to resume BP medication. RESULTS: Proportional hazards regression analyses indicated that the hazard (+/- SE) of experiencing an end point among persons assigned to active interventions was 75% +/- 9% (weight loss), 68% +/- 7% (sodium reduction), and 55% +/- 7% (combined weight loss/sodium reduction) that of the hazard for those assigned to usual care. Lower baseline systolic BP (P < .001), fewer years since diagnosis of hypertension (P < .001), fewer years of antihypertensive treatment (P < .001), and no history of cardiovascular disease (P = .01) were important predictors of maintaining successful nonpharmacological BP control throughout follow-up, based on logistic regression analysis. Age, ethnicity, baseline level of physical activity baseline weight, medication class, smoking status, and alcohol intake were not statistically significant predictors. During follow-up, the extent of weight loss (P = .001) and urinary sodium excretion (P = .04) were associated with a reduction in the risk of trial end points in a graded fashion. CONCLUSIONS: Withdrawal from antihypertensive medication is most likely to be successful in patients with well-controlled hypertension who have been recently (within 5 years) diagnosed or treated, and who adhere to life-style interventions involving weight loss and sodium reduction. More than 80% of these patients may have success in medication withdrawal for longer than 1 year.

Aged↗
PubMedDate not supplied

Lipid risk profile and weight stability after gastric restrictive operations for morbid obesity.

There are no longitudinal data that address weight loss stability and lipid levels in bariatric surgical patients. The goal of this study was to determine whether weight regain adversely affected reduction in lipid levels after gastric bariatric operations. Of 651 consecutive patients undergoing gastric restrictive surgery for morbid obesity, 227 (35%) had increased serum levels of total cholesterol (TC), triglycerides, or both preoperatively. High-density lipoprotein cholesterol (HDL-C) levels were subnormal (</=35 mg/dl) in 45 (20%) of the hyperlipidemic patients. Fasting lipid profiles were determined at 6-month intervals postoperatively. This series included the following three operations: gastroplasty (GP; N = 13), standard Roux-en-Y gastric bypass (RYGB; N = 205), and distal Roux-en-Y gastric bypass (DRY; N = 9). By 6 months postoperatively, patients had a >/=15% mean reduction in TC and a >/=50% mean reduction in triglycerides, both of which were significant in comparison with preoperative levels (P </=0.05). Mean HDL-C levels had increased significantly vs. preoperative levels by 12 months postoperative y (P <0.05) and continued to increase through 5 years. By 18 months both HDL-C and TC were significantly lower after DRY than after GP or RYGB. In 91 patients who were followed for 2 years or longer (mean 48 +/- 25 months), mean excess weight loss was 55% with mean body mass index reduced from 48 to 33 kg/m(2). This group was divided into patients whose weight remained stable (N = 54) and patients who regained >/=15% of their lost weight or lost less than 50% of excess weight (N = 37). Although mean excess weight loss and body mass index were significantly different between the two groups (P <0.0001) at 2 years, there was no difference in the lipid profile (TC/HDL) between the two groups at any interval through 5 years. These results show that abnormal lipid profiles can be permanently improved after gastric bariatric surgery and are not adversely affected by mediocre weight loss or regaining >/=15% of lost weight. DRY appears to be a superior operation for TC reduction in comparison with GP and RYGB.

Adult↗
PubMedDate not supplied

DNA sequences from the quagga, an extinct member of the horse family.

To determine whether DNA survives and can be recovered from the remains of extinct creatures, we have examined dried muscle from a museum specimen of the quagga, a zebra-like species (Equus quagga) that became extinct in 1883 (ref. 1). We report that DNA was extracted from this tissue in amounts approaching 1% of that expected from fresh muscle, and that the DNA was of relatively low molecular weight. Among the many clones obtained from the quagga DNA, two containing pieces of mitochondrial DNA (mtDNA) were sequenced. These sequences, comprising 229 nucleotide pairs, differ by 12 base substitutions from the corresponding sequences of mtDNA from a mountain zebra, an extant member of the genus Equus. The number, nature and locations of the substitutions imply that there has been little or no postmortem modification of the quagga DNA sequences, and that the two species had a common ancestor 3-4 Myr ago, consistent with fossil evidence concerning the age of the genus Equus.

Animals↗
PubMedDate not supplied

Wormy mice in a hybrid zone.

As one approach to analysing the genetic barriers between species, we studied the numbers and types of parasitic worms in two species of house mice (Mus musculus and M. domesticus) and in their natural hybrids. Where the ranges of these two species meet in southern Germany, there is a zone of hybridization less than 20 kilometres across, in which about 98% of the mice have backcross genotypes. Fourteen of the 46 mice tested from within the zone have over 500 pinworms per gut, a number far exceeding the mean of 40 per gut for other mice inside and outside the zone. Other nematodes have a similar, non-random distribution. The number of mice bearing 9 or more tapeworms per gut is also excessive in the hybrid zone. These extraordinarily wormy mice may be unusually susceptible to parasitism; the different species may have different genes for resistance, and recombinant backcross animals may lose both. Our findings support the view that the hybrid populations may have reduced fitness and thereby act as a genetic sink, interfering with the flow of genes between the two species. The possibility that environmental or ecological peculiarites in the zone of hybridization make the mice more liable to infection is not supported.

Animals↗
PubMedDate not supplied

Mitochondrial DNA and human evolution.

Mitochondrial DNAs from 147 people, drawn from five geographic populations have been analysed by restriction mapping. All these mitochondrial DNAs stem from one woman who is postulated to have lived about 200,000 years ago, probably in Africa. All the populations examined except the African population have multiple origins, implying that each area was colonised repeatedly.

Biological Evolution↗