Pedro Guimarães

Dr. Pedro Guimarães

orcid

Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

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

Representative Publications

View All Publications
1 May 2020 in JAMA Oncology
Verified
Journal Article
Open access
PDF file
TFTobias Fehlmann
Tobias Fehlmann
MKMustafa Kahraman
Mustafa Kahraman
NLNicole Ludwig
Nicole Ludwig
CBChristina Backes
Christina Backes
VGValentina Galata
Valentina Galata
AKAndreas Keller
Andreas Keller
Lung cancer is among the 3 most common cancers among both sexes and is the leading cause of cancer-related deaths worldwide.1,2 Despite decreasing smoking rates in industrial countries, millions of current or former heavy smokers have an elevated risk of developing lung cancer, including more than 90 million people in the United States.3 Because the symptoms of lung cancer may not be obvious in its early stages, more than two-thirds of all cases are detected in late and inoperable stages. Patients with metastatic stage IV lung cancer have a 5-year survival rate of only 4.7% compared with a 5-year survival rate of up to 56.3% for those with stage I cancer.4

2 August 2019 in Gut
Verified
Journal Article
Open access
PDF file
PGPedro Guimarães
Pedro Guimarães
AKAndreas Keller
Andreas Keller
TFTobias Fehlmann
Tobias Fehlmann
FLFrank Lammert
Frank Lammert
MCMarkus Casper
Markus Casper

28 March 2018 in Scientific Reports
Verified
Journal Article
Open access
PDF file
HPHans-Ulrich Prommer
Hans-Ulrich Prommer
JMJohannes Maurer
Johannes Maurer
KWKaroline von Websky
Karoline von Websky
CFChristian Freise
Christian Freise
KSKerstin Sommer
Kerstin Sommer
UQUwe Querfeld
Uwe Querfeld
Chronic kidney disease (CKD) is associated with excessive mortality from cardiovascular disease (CVD). Endothelial dysfunction, an early manifestation of CVD, is consistently observed in CKD patients and might be linked to structural defects of the microcirculation including microvascular rarefaction. However, patterns of microvascular rarefaction in CKD and their relation to functional deficits in perfusion and oxygen delivery are currently unknown. In this in-vivo microscopy study of the cremaster muscle microcirculation in BALB/c mice with moderate to severe uremia, we show in two experimental models (adenine feeding or subtotal nephrectomy), that serum urea levels associate incrementally with a distinct microangiopathy. Structural changes were characterized by a heterogeneous pattern of focal microvascular rarefaction with loss of coherent microvascular networks resulting in large avascular areas. Corresponding microvascular dysfunction was evident by significantly diminished blood flow velocity, vascular tone, and oxygen uptake. Microvascular rarefaction in the cremaster muscle paralleled rarefaction in the myocardium, which was accompanied by a decrease in transcription levels not only of the transcriptional regulator HIF-1α, but also of its target genes Angpt-2, TIE-1 and TIE-2, Flkt-1 and MMP-9, indicating an impaired hypoxia-driven angiogenesis. Thus, experimental uremia in mice associates with systemic microvascular disease with rarefaction, tissue hypoxia and dysfunctional angiogenesis.

11 February 2013 in Brain
Verified
Journal Article
Open access
PDF file
IVInês R. Violante
Inês R. Violante
MRMaria José Ribeiro
Maria José Ribeiro
RERichard A. E. Edden
Richard A. E. Edden
PGPedro Guimarães
Pedro Guimarães
IBInês Bernardino
Inês Bernardino
Miguel Castelo-BrancoMiguel Castelo-Branco
Miguel Castelo-Branco
Alterations in the balance between excitatory and inhibitory neurotransmission have been implicated in several neurodevelopmental disorders. Neurofibromatosis type 1 is one of the most common monogenic disorders causing cognitive deficits for which studies on a mouse model (Nfl+/−) proposed increased γ-aminobutyric acid-mediated inhibitory neurotransmission as the neural mechanism underlying these deficits. To test whether a similar mechanism translates to the human disorder, we used magnetic resonance spectroscopy to measure γ-aminobutyric acid levels in the visual cortex of children and adolescents with neurofibromatosis type 1 (n = 20) and matched control subjects (n = 26). We found that patients with neurofibromatosis type 1 have significantly lower γ-aminobutyric acid levels than control subjects, and that neurofibromatosis type 1 mutation type significantly predicted cortical γ-aminobutyric acid. Moreover, functional imaging of the visual cortex indicated that blood oxygen level-dependent signal was correlated with γ-aminobutyric acid levels both in patients and control subjects. Our results provide in vivo evidence of γ-aminobutyric acidergic dysfunction in neurofibromatosis type 1 by showing a reduction in γ-aminobutyric acid levels in human patients. This finding is relevant to understand the physiological profile of the disorder and has implications for the identification of targets for therapeutic strategies.

14 May 2020 in Scientific Reports
Verified
Journal Article
Open access
PDF file
PGPedro Guimarães
Pedro Guimarães
ABAna Batista
Ana Batista
MZMichael Zieger
Michael Zieger
MKMartin Kaatz
Martin Kaatz
KKKarsten Koenig
Karsten Koenig
The diagnostic possibilities of multiphoton tomography (MPT) in dermatology have already been demonstrated. Nevertheless, the analysis of MPT data is still time-consuming and operator dependent. We propose a fully automatic approach based on convolutional neural networks (CNNs) to fully realize the potential of MPT. In total, 3,663 MPT images combining both morphological and metabolic information were acquired from atopic dermatitis (AD) patients and healthy volunteers. These were used to train and tune CNNs to detect the presence of living cells, and if so, to diagnose AD, independently of imaged layer or position. The proposed algorithm correctly diagnosed AD in 97.0 ± 0.2% of all images presenting living cells. The diagnosis was obtained with a sensitivity of 0.966 ± 0.003, specificity of 0.977 ± 0.003 and F-score of 0.964 ± 0.002. Relevance propagation by deep Taylor decomposition was used to enhance the algorithm’s interpretability. Obtained heatmaps show what aspects of the images are important for a given classification. We showed that MPT imaging can be combined with artificial intelligence to successfully diagnose AD. The proposed approach serves as a framework for the automatic diagnosis of skin disorders using MPT.

1 December 2017 in Investigative Ophthalmology & Visual Science
Verified
Journal Article
Open access
PDF file
NLNeil Satish Lagali
Neil Satish Lagali
SAStephan Allgeier
Stephan Allgeier
PGPedro Guimarães
Pedro Guimarães
RBReza A. Badian
Reza A. Badian
ARAlfredo Ruggeri
Alfredo Ruggeri
OROlov Rolandsson
Olov Rolandsson
Purpose: To determine if corneal subbasal nerve plexus (SBP) parameters derived from wide-area depth-corrected mosaic images are associated with type 2 diabetes. Methods: One hundred sixty-three mosaics were produced from eyes of 82 subjects by laser-scanning in vivo confocal microscopy (IVCM). Subjects were of the same age, without (43 subjects) or with type 2 diabetes (39 subjects). Mosaic corneal nerve fiber length density (mCNFL) and apical whorl corneal nerve fiber length density (wCNFL) were quantified and related to the presence and duration of diabetes (short duration < 10 years and long duration ≥ 10 years). Results: In mosaics with a mean size of 6 mm2 in subjects aged 69.1 ± 1.2 years, mCNFL in type 2 diabetes was reduced relative to nondiabetic subjects (13.1 ± 4.2 vs. 15.0 ± 3.2 mm/mm2, P = 0.018). Also reduced relative to nondiabetic subjects was mCNFL in both short-duration (14.0 ± 4.0 mm/mm2, 3.2 ± 3.9 years since diagnosis) and long-duration diabetes (12.7 ± 4.2 mm/mm2, 15.4 ± 4.2 years since diagnosis; ANOVA P = 0.023). Lower mCNFL was associated with presence of diabetes (P = 0.032) and increased hemoglobin A1c (HbA1c) levels (P = 0.047). By contrast, wCNFL was unaffected by diabetes or HbA1c (P > 0.05). Global SBP patterns revealed marked degeneration of secondary nerve fiber branches outside the whorl region in long-duration diabetes. Conclusions: Wide-area mosaic images provide reference values for mCNFL and wCNFL and reveal a progressive degeneration of the SBP with increasing duration of type 2 diabetes.