Hemoglobin concentration of high-altitude Tibetans and Bolivian Aymara

Elevated hemoglobin concentrations have been reported for high-altitude sojourners and Andean high-altitude natives since early in the 20th century. Thus, reports that have appeared since the 1970s describing relatively low hemoglobin concentration among Tibetan high-altitude natives were unexpected. These suggested a hypothesis of population differences in hematological response to high-altitude hypoxia. A case of quantitatively different responses to one environmental stress would offer an opportunity to study the broad evolutionary question of the origin of adaptations. However, many factors may confound population comparisons. The present study was designed to test the null hypothesis of no difference in mean hemoglobin concentration of Tibetan and Aymara native residents at 3,800–4,065 meters by using healthy samples that were screened for iron deficiency, abnormal hemoglobins, and thalassemias, recruited and assessed using the same techniques. The hypothesis was rejected, because Tibetan males had a significantly lower mean hemoglobin concentration of 15.6 gm/dl compared with 19.2 gm/dl for Aymara males, and Tibetan females had a mean hemoglobin concentration of 14.2 gm/dl compared with 17.8 gm/dl for Aymara females. The Tibetan hemoglobin distribution closely resembled that from a comparable, sea-level sample from the United States, whereas the Aymara distribution was shifted toward 3–4 gm/dl higher values. Genetic factors accounted for a very high proportion of the phenotypic variance in hemoglobin concentration in both samples (0.86 in the Tibetan sample and 0.87 in the Aymara sample). The presence of significant genetic variance means that there is the potential for natural selection and genetic adaptation of hemoglobin concentration in Tibetan and Aymara high-altitude populations. Am J Phys Anthropol 106:385–400, 1998. © 1998 Wiley-Liss, Inc.     

Amplitude Integrated Electroencephalogram as a Prognostic Tool in Neonates with Hypoxic-Ischemic Encephalopathy: A Systematic Review

IntroductionPerinatal management and prognostic value of clinical evaluation and diagnostic tools have changed with the generalization of therapeutic hypothermia (TH) in infants with hypoxic-ischemic encephalopathy (HIE)Aimto ascertain the prognostic value of amplitude integrated electroencephalogram (aEEG) in neonates with HIE considering hours of life and treatment with TH.MethodsA systematic review was performed. Inclusion criteria were studies including data of neonates with HIE, treated or not with TH, monitored with aEEG and with neurodevelopmental follow-up of at least 12 months. The period of bibliographic search was until February 2016. No language restrictions were initially applied. Consulted databases were MEDLINE, Scopus, CINHAL and the Spanish language databases GuiaSalud and Bravo. Article selection was performed by two independent reviewers. Quality for each individual paper selected was evaluated using QUADAS-2. Review Manager (RevMan) version 5.3 software was used. Forest plots were constructed to graphically show sensitivity and specificity for all included studies, separating patients treated or not with hypothermia. Summary statistics were estimated using bivariate models and random effects approaches with the R package MADA from summary ROC curves. Meta-regression was used to estimate heterogeneity and trends.Resultsfrom the 403 articles initially identified, 17 were finally included and critically reviewed. In infants not treated with hypothermia the maximum reliability of an abnormal aEEG background to predict death or moderate/severe disability was at 36 hours of life, when a positive post-test probability of 97.90% was achieved (95%CI 88.40 to 99.40%). Positive likelihood ratio (+LR) at these hours of life was 26.60 (95%CI 4.40 to 94.90) and negative likelihood ratio (-LR) was 0.23 (95%CI 0.10 to 0.44). A high predictive value was already present at 6 hours of life in this group of patients, with a positive post-test probability of 88.20% (95%CI 79.80 to 93%) and a +LR of 4.34 (95%CI 2.31 to 7.73). In patients treated with TH the maximum predictive reliability was achieved at 72 hours of life (post-test probability of 95.70%, 95%CI 84.40 to 98.50%). +LR at this age was 24.30 (95%CI 5.89 to 71.30) and–LR was 0.40 (95%CI 0.25 to 0.57). Predictive value of aEEG at 6 hours of life was low in these patients (59.10%, 95%CI 55.70 to 63%).ConclusionThis study confirms that aEEG´s background activity, as recorded during the first 72 hours after birth, has a strong predictive value in infants with HIE treated or not with TH. Predictive values of traces throughout the following 72 hours are a helpful guide when considering and counselling parents about the foreseeable long-term neurological outcome     

Evolution of antibiotic resistance genes: the DNA sequence of a kanamycin resistance gene from Staphylococcus aureus

The kanamycin resistance gene from Staphylococcus aureus has been sequenced and its structure compared with similar genes isolated from Streptomyces fradiae and from two transposons, Tn5 and Tn903, originally isolated from Klebsiella pneumoniae and Salmonella typhimurium, respectively. The genes are all homologous but, since their common ancestor, have undergone extensive divergence, with more than 43% divergence between the closest pair. The phylogeny of the genes cannot be made congruent to the phylogeny of the taxa from which they were isolated without requiring rather improbable differences in rates. One is therefore led to conclude that there have been multiple occurrences of gene transfer between these species. Thus, although they are homologous, they are neither orthologous nor paralogous. It is suggested that homologous genes of this type be called xenologous.      

Levels of 15-keto-1344-dihydro-PFG2α, Progesterone and Oestradiol-17β after Induced Ovulations in Llamas and Alpacas

Six llamas and 6 alpacas were mated to vasectomized males; ovulation and corpus luteum formation followed. Progesterone in blood was elevated from day 5 and reached maximum concentrations of 10–20 nmol/1 on day 7–8. A rapid decline in progesterone levels occurred on day 9–10 in connection with repeated surge releases of prostaglandin F2α. Oestradiol-17β levels were > 100–200 pmol/1 during oestrus when the animals were mated. These high levels might have been caused by coital stimulation. A temporary increase was detected in connection with the rise in progesterone levels in the early luteal phase. With this exception levels of oestradiol stayed low, 20–40 pmol/1 during the luteal phase but rose in most animals after luteolysis to 40–60 pmol/1.     

Screening known Cerambycidae pheromones for activity with the Peruvian fauna

1. Semiochemicals are powerful tools for the surveillance and suppression of forest insects. Although the literature on the chemical ecology of and use of semiochemicals to manage the Cerambycidae is growing, little is known about the chemical ecology of Cerambycidae fauna in Peru.
2. Trapping studies that screen known attractants in off-shore mitigation programs can provide valuable baseline knowledge to inform management of species introduced outside their native range.
3. Known Cerambycidae pheromones were screened for activity in a year-long field study in Peru to look for activity in the local Cerambycidae fauna.
4. The most frequently captured species were Megacyllene andesiana (Casey), Oreodera bituberculata Bates, Aegomorphus longitarsis (Bates) and Discopus eques Bates.
5. The activity period of A. longitarsis, O. bituberculata and D. eques occurred in mid-September 2020 and for M. andesiana occurred in early October 2020.
6. Responses to anti-2,3-hexanediol, fuscumol and fuscumol acetate by M. andesiana, O. bituberculata and D. eques were observed.
7. We observed antagonism of the responses of M. andesiana, O. bituberculata and D. eques when anti-2,3-hexanediol, fuscumol and fuscumol acetate were tested in blends.

     

Acrolein, a component of a universal cell-growth regulatory system: a theory

An hypothesis suggesting that acrolein might form part of a universal cell-growth regulatory system is presented. This unsaturated aldehyde appears, better than any other compound proposed so far, to fulfill the structural requirements and characteristics of the universal growth-inhibitor predicted in Szent-Gyorgyi's bioelectronic theory.     

Megakaryocyte colony-stimulating factor (Mk-CSF): its physiologic significance

Megakaryocyte colony-stimulating activity (Mk-CSA) is required for in vitro megakaryocyte colony formation. Its in vivo significance in megakaryocytopoiesis is unknown. We studied 12 patients undergoing bone marrow transplantation (BMT) at our institution. The bone marrow megakaryocyte progenitor cells (CFU-Mk), the serum level of Mk-CSA, and the platelet count on the 28th day after BMT were studied. Patients with elevated Mk-CSA levels had less CFU-Mk in their bone marrow than did patients with a normal or decreased Mk-CSA (p less than 0.01). Animal experiments using murine models have documented that several purified molecules including erythropoietin, multi-CSF and GM-CSF possess Mk-CSA. The in vitro Mk-CSF of WEHI-3-conditioned medium is multi-CSF. The in vivo significance for megakaryocytopoiesis of these factors is not clear. In the human system, Mk-CSA is increased in conditions with decreased bone marrow megakaryocytes. Recombinant human or primate CSFs have in vitro Mk-CSA utilizing both human and murine cells as targets. However, the presence of these activities does not fully explain the Mk-CSA in human serum rich in Mk-CSA. The precise regulation of human blood cell levels and the studies discussed suggest that there is a specific Mk-CSF that responds to in vivo changes in megakaryocyte numbers. Proof of its physiologic role awaits the isolation of a pure factor.