Alexis Fonseca Welker

Prof. Dr. Alexis Fonseca Welker

Universidade de Brasília, Brasília, Distrito Federal, Brazil
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Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 August 2013 in Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
Verified
Journal Article
Closed access
AWAlexis Fonseca Welker
Alexis Fonseca Welker
DMDaniel C. Moreira
Daniel C. Moreira
ÉCÉlida G. Campos
Élida G. Campos
Marcelo Hermes-LimaMarcelo Hermes-Lima
Marcelo Hermes-Lima

1 September 2010 in Physiological and Biochemical Zoology
Verified
Journal Article
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TGThomas Gorr
Thomas Gorr
DWD. Wichmann
D. Wichmann
JHJ. Hu
J. Hu
Marcelo Hermes-LimaMarcelo Hermes-Lima
Marcelo Hermes-Lima
AWAlexis Fonseca Welker
Alexis Fonseca Welker
MGM. Gassmann
M. Gassmann
Many invertebrates and ectothermic vertebrates successfully cope with a fluctuating supply of ambient oxygen—and consequently, a highly variable tissue oxygenation—through increasing their antioxidant barriers. During chronic deprivation of oxygen, however, the hypometabolic defense mode of the fruit fly Drosophila, the hypoxia‐induced behavioral hypothermia of the crayfish Pacifastacus leniusculus, and the production of ethanol during anoxia by the crucian carp Carassius carassius all indicate that these animals are also capable of utilizing a suite of genetic and physiological defenses to survive otherwise lethal reductions in tissue oxygenation. Normally, much of an organism’s gene response to hypoxia is orchestrated via the hypoxia‐inducible transcription factor HIF. Recent developments expand our view of HIF function even further by highlighting regulatory roles for HIF in the hypometabolism of insects, in the molting and the normoxic immune response of crustaceans, and in the control—via the downstream effector gene erythropoietin—of the hypoxic ventilatory response and pulmonary hypertension in mammals. These and related topics were collectively presented by the authors in a symposium of the 2008 ICA‐CBP conference at Mara National Reserve, Kenya, Africa. This synthesis article communicates the essence of the symposium presentations to the wider community.

1 May 2012 in American Journal of Physiology-Regulatory, Integrative and Comparative Physiology
Verified
Journal Article
Open access
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AWAlexis Fonseca Welker
Alexis Fonseca Welker
ÉCÉlida G. Campos
Élida G. Campos
LCLuciano A. Cardoso
Luciano A. Cardoso
Marcelo Hermes-LimaMarcelo Hermes-Lima
Marcelo Hermes-Lima
The specific contribution of each antioxidant enzyme to protection against the reoxygenation-associated oxidative stress after periods of hypoxia is not well understood. We assessed the physiological role of catalase during posthypoxic reoxygenation by the combination of two approaches. First, catalase activity of Nile tilapias ( Oreochromis niloticus ) was 90% suppressed by intraperitoneal injection of 3-amino-1,2,4-triazole (ATZ, 1g/kg). In ATZ-injected fish, liver GSH levels, oxidative stress markers, and activities of other antioxidant enzymes remained unchanged. Second, animals with depleted catalase activity (or those saline-injected) were subjected to a cycle of severe hypoxia (dissolved O2= 0.28 mg/l for 3 h) followed by reoxygenation (0.5 to 24 h). Hypoxia did not induce changes in the above-mentioned parameters, either in saline- or in ATZ-injected animals. Reoxygenation increased superoxide dismutase activity in saline-injected fish, whose levels were similar to ATZ-injected animals. The activities of glutathione S-transferase, selenium-dependent glutathione peroxidase, and total-GPX and the levels of GSH-eq, GSSG, and thiobarbituric acid reactive substances remained unchanged during reoxygenation in both saline- and ATZ-injected fish. The GSSG/GSH-eq ratio in ATZ-injected fish increased at 30 min of reoxygenation compared with saline-injected ones. Reoxygenation also increased carbonyl protein levels in saline-injected fish, whose levels were similar to the ATZ-injected group. Our work shows that inhibition of liver tilapia catalase causes a redox imbalance during reoxygenation, which is insufficient to induce further oxidative stress. This indicates the relevance of hepatic catalase for hypoxia/reoxygenation stress in tilapia fish.

1 November 2003 in Journal of Comparative Physiology B
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Journal Article
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MFM. B. Freitas
M. B. Freitas
AWAlexis Fonseca Welker
Alexis Fonseca Welker
SMS. F. Millan
S. F. Millan
EPE. C. Pinheiro
E. C. Pinheiro

7 October 2011
Verified
Book Chapter
Closed access
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CFCarolina A. Freire
Carolina A. Freire
AWAlexis Fonseca Welker
Alexis Fonseca Welker
JSJanet M. Storey
Janet M. Storey
KSKenneth B. Storey
Kenneth B. Storey
Marcelo Hermes-LimaMarcelo Hermes-Lima
Marcelo Hermes-Lima

21 September 2017 in Developmental Neurorehabilitation
Verified
Journal Article
Closed access
DMDenise Lica Yoshimura Mikami
Denise Lica Yoshimura Mikami
CFCristina Lemos Barbosa Furia
Cristina Lemos Barbosa Furia
AWAlexis Fonseca Welker
Alexis Fonseca Welker
Objective: To evaluate the effects of Kinesio Taping (KT) of the orbicularis oris muscles as an adjunct to standard therapy for drooling. Methods: Fifteen children with neurological disorders and drooling received speech therapy and twice-weekly KT of the orbicularis muscles over a 30-day period. Drooling was assessed by six parameters: impact on the life of the child and caregiver; severity of drooling; frequency of drooling; drooling volume (estimated by number of bibs used); salivary leak; and interlabial gap. Seven markers of oral motor skills were also assessed. Results: KT of the orbicularis oris region reduced the interlabial gap. All oral motor skills and almost all markers of drooling improved after 15 days of treatment. Conclusion: In this sample of children with neurological disorders, adding KT of the orbicularis oris muscles to speech therapy caused rapid improvement in oral motor skills and drooling.