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result(s) for
"Martins, Ana Raquel O"
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Coordinated forms of noradrenergic plasticity in the locus coeruleus and primary auditory cortex
2015
The locus coeruleus is a major neuromodulatory center for the mammalian brain. Here, the authors show that presenting sounds when locus coeruleus is active leads to enduring modifications of responses in auditory cortex and locus coeruleus. These synaptic and spiking changes have a profound effect on auditory perception for weeks.
The cerebral cortex is plastic and represents the world according to the significance of sensory stimuli. However, cortical networks are embodied in complex circuits, including neuromodulatory systems such as the noradrenergic locus coeruleus, providing information about internal state and behavioral relevance. Although norepinephrine is important for cortical plasticity, it is unknown how modulatory neurons themselves respond to changes of sensory input. We examined how locus coeruleus neurons are modified by experience and the consequences of locus coeruleus plasticity for cortical representations and sensory perception. We made whole-cell recordings from rat locus coeruleus and primary auditory cortex (A1), pairing sounds with locus coeruleus activation. Although initially unresponsive, locus coeruleus neurons developed and maintained auditory responses afterwards. Locus coeruleus plasticity induced changes in A1 responses lasting at least hours and improved auditory perception for days to weeks. Our results demonstrate that locus coeruleus is highly plastic, leading to substantial changes in regulation of brain state by norepinephrine.
Journal Article
Long-term modification of cortical synapses improves sensory perception
by
Zaika, Natalya
,
Yuan, Kexin
,
Bernstein, Hannah
in
631/378/2620
,
Acoustic Stimulation
,
Anesthetics - pharmacology
2013
By pairing acoustic stimuli and electrical stimulation of the nucleus basalis neuromodulatory system in rats, the authors show an induction of long-lasting synaptic modifications of the auditory cortex that conserved excitation across the auditory receptive fields. This type of modification also improved auditory sensory detection and behavioral performance in tone perception.
Synapses and receptive fields of the cerebral cortex are plastic. However, changes to specific inputs must be coordinated within neural networks to ensure that excitability and feature selectivity are appropriately configured for perception of the sensory environment. We induced long-lasting enhancements and decrements to excitatory synaptic strength in rat primary auditory cortex by pairing acoustic stimuli with activation of the nucleus basalis neuromodulatory system. Here we report that these synaptic modifications were approximately balanced across individual receptive fields, conserving mean excitation while reducing overall response variability. Decreased response variability should increase detection and recognition of near-threshold or previously imperceptible stimuli. We confirmed both of these hypotheses in behaving animals. Thus, modification of cortical inputs leads to wide-scale synaptic changes, which are related to improved sensory perception and enhanced behavioral performance.
Journal Article
Thrombectomy for Stroke in the Public Health Care System of Brazil
by
Martins, Sheila O
,
Bezerra, Daniel C
,
Liebeskind, David S
in
Cardiovascular system
,
Carotid arteries
,
Clinical trials
2020
Endovascular thrombectomy has been effective in reducing stroke-related disability in high-income countries. This trial in the public health care system of Brazil, a developing country, showed similar effectiveness in patients treated within 8 hours after the onset of symptoms.
Journal Article
Pd(II) and Pt(II) Trinuclear Chelates with Spermidine: Selective Anticancer Activity towards TNBC-Sensitive and -Resistant to Cisplatin
by
Ramos, Raquel
,
Duarte, Sara Gomes
,
Martins, Clara B.
in
antiproliferative
,
Breast cancer
,
Cancer therapies
2023
Triple-negative breast cancer (TNBC) is one of the most aggressive forms of breast cancer and constitutes 10–20% of all breast cancer cases. Even though platinum-based drugs such as cisplatin and carboplatin are effective in TNBC patients, their toxicity and development of cancer drug resistance often hamper their clinical use. Hence, novel drug entities with improved tolerability and selectivity profiles, as well as the ability to surpass resistance, are needed. The current study focuses on Pd(II) and Pt(II) trinuclear chelates with spermidine (Pd3Spd2 and Pt3Spd2) for evaluating their antineoplastic activity having been assessed towards (i) cisplatin-resistant TNBC cells (MDA-MB-231/R), (ii) cisplatin-sensitive TNBC cells (MDA-MB-231) and (iii) non-cancerous human breast cells (MCF-12A, to assess the cancer selectivity/selectivity index). Additionally, the complexes’ ability to overcome acquired resistance (resistance index) was determined. This study revealed that Pd3Spd2 activity greatly exceeds that displayed by its Pt analog. In addition, Pd3Spd2 evidenced a similar antiproliferative activity in both sensitive and resistant TNBC cells (IC50 values 4.65–8.99 µM and 9.24–13.34 µM, respectively), with a resistance index lower than 2.3. Moreover, this Pd compound showed a promising selectivity index ratio: >6.28 for MDA-MB-231 cells and >4.59 for MDA-MB-231/R cells. Altogether, the data presently gathered reveal Pd3Spd2 as a new, promising metal-based anticancer agent, which should be further explored for the treatment of TNBC and its cisplatin-resistant forms.
Journal Article
Randomized clinical trial of photobiomodulation and glass ionomer sealant for hypersensitivity in molar incisor hypomineralization
by
dos Santos-Pinto, Lourdes Aparecida Martins
,
Horliana, Anna Carolina Ratto Tempestini
,
Sobral, Ana Paula Taboada
in
639/624
,
692/1807
,
Child
2025
This study evaluated the impact of photobiomodulation (PBM) combined with glass ionomer sealant on hypersensitivity, oral hygiene, and sealant retention in molars affected by molar incisor hypomineralization (MIH). Forty-nine children (6–12 years) with MIH (Grade 3, 4a, or 4b) per MIH-TNI criteria were randomly assigned to two groups: control (n = 25, fluoride toothpaste, sealant with self-curing glass ionomer cement, simulated PBM) and treatment (n = 24, fluoride toothpaste, sealant with self-curing glass ionomer cement, active PBM). Hypersensitivity (SCASS, VAS), oral hygiene (OHI-S), and sealant retention (CCC system) were assessed. Forty-six children completed the study and were evaluated. At all post-baseline time points, the treatment group showed significantly lower VAS and SCASS scores (
p
< 0.05). OHI-S improved in both groups, with a positive correlation between reduced hypersensitivity and better oral hygiene. Sealant retention was higher in the treatment group after 30 days, with 56.5% of teeth showing complete retention versus 17.4% in the control group (
p
= 0.002). In the control group, greater hypersensitivity correlated with worse retention. PBM combined with glass ionomer cement reduces hypersensitivity, improves oral hygiene, and enhances sealant retention in MIH-affected molars. The combined treatment provides superior results in hypersensitivity reduction and sealant retention compared to sealant alone, offering a more effective approach for managing MIH.
Trial registration
: NCT05370417 in ClinicalTrials.gov
Journal Article
Craniotabes in Newborns and the Role of Maternal Vitamin D Deficiency: A Case Series
by
Ferraz, Ana
,
Martins, Marta O
,
Pita, Rita M
in
Endocrinology/Diabetes/Metabolism
,
Family/General Practice
,
Pediatrics
2024
Craniotabes is characterized by the softening of skull bones in newborns. It can be associated with conditions like rickets, congenital syphilis, and osteogenesis imperfecta. In otherwise healthy newborns, craniotabes is often linked to in utero vitamin D deficiency. We report four cases of term infants diagnosed with craniotabes at birth. For all cases, laboratory tests confirmed vitamin D deficiency with serum 25-hydroxyvitamin D levels below 20 ng/mL, alongside maternal vitamin D deficiency. While three cases showed no complications, one newborn had a skull fracture and a neonatal stroke. All infants were supplemented with oral cholecalciferol, resulting in the normalization of serum 25-hydroxyvitamin D levels and resolution of the skull softening. These cases highlight the critical role of maternal vitamin D levels in fetal bone development and the potential risks of its deficiency. Although craniotabes associated with maternal vitamin D deficiency is a known condition among neonatologists, these cases help to increase awareness of this diagnosis. We highlight the need for thorough clinical examination, along with complementary diagnostic tests, to identify any related complications.
Journal Article
Diagnostic application of sensitive and specific phage-exposed epitopes for visceral leishmaniasis and human immunodeficiency virus coinfection
by
Ramos, Fernanda F.
,
Martins, Vívian T.
,
Cota, Gláucia F.
in
Antigens
,
Bacteriophages
,
Bioinformatics
2021
The diagnosis of visceral leishmaniasis (VL) has improved with the search of novel antigens; however, their performance is limited when samples from VL/human immunodeficiency virus (HIV)-coinfected patients are tested. In this context, studies conducted to identify more suitable antigens to detect both VL and VL/HIC coinfection cases should be performed. In the current study, phage display was performed using serum samples from healthy subjects and VL, HIV-infected and VL/HIV-coinfected patients; aiming to identify novel phage-exposed epitopes to be evaluated with this diagnostic purpose. Nine non-repetitive and valid sequences were identified, synthetized and tested as peptides in enzyme-linked immunosorbent assay experiments. Results showed that three (Pep2, Pep3 and Pep4) peptides showed excellent performance to diagnose VL and VL/HIV coinfection, with 100% sensitivity and specificity values. The other peptides showed sensitivity varying from 50.9 to 80.0%, as well as specificity ranging from 60.0 to 95.6%. Pep2, Pep3 and Pep4 also showed a potential prognostic effect, since specific serological reactivity was significantly decreased after patient treatment. Bioinformatics assays indicated that Leishmania trypanothione reductase protein was predicted to contain these three conformational epitopes. In conclusion, data suggest that Pep2, Pep3 and Pep4 could be tested for the diagnosis of VL and VL/HIV coinfection.
Journal Article
Magnetoliposomes Incorporated in Peptide-Based Hydrogels: Towards Development of Magnetolipogels
by
Veloso, Sérgio R. S.
,
Ferreira, Paula M. T.
,
Andrade, Raquel G. D.
in
Aqueous solutions
,
Arrays
,
Biocompatibility
2020
A major problem with magnetogels is the encapsulation of hydrophobic drugs. Magnetoliposomes not only provide these domains but also improve drug stability and avert the aggregation of the magnetic nanoparticles. In this work, two magnetoliposome architectures, solid and aqueous, were combined with supramolecular peptide-based hydrogels, which are of biomedical interest owing to their biocompatibility, easy tunability, and wide array of applications. This proof-of-concept was carried out through combination of magnetoliposomes (loaded with the model drug curcumin and the lipid probe Nile Red) with the hydrogels prior to pH triggered gelation, and fluorescence spectroscopy was used to assess the dynamics of the encapsulated molecules. These systems allow for the encapsulation of a wider array of drugs. Further, the local environment of the encapsulated molecules after gelation is unaffected by the used magnetoliposome architecture. This system design is promising for future developments on drug delivery as it provides a means to independently modify the components and adapt and optimize the design according to the required conditions.
Journal Article
Sociodemographic, Clinical, and Behavioral Factors Associated with Sexual Transmitted Infection among HIV-1 Positive Migrants in Portugal: Are There Differences between Sexes?
by
Mansinho, Kamal
,
Correia de Abreu, Ricardo
,
Poças, José
in
Adult
,
Behavior
,
Blood transfusion
2024
Introduction: Sexually transmitted infections (STIs) continue to occur at high levels. According to the WHO, each year there are an estimated 374 million new infections with syphilis, gonorrhea, chlamydia, and trichomoniasis. STIs are associated with an increased risk of acquiring HIV infection. Migrants are reportedly highly affected by STIs. Objectives: This study aims to characterize factors associated with STIs in a population of HIV-positive migrants living in Portugal. Methodology: This is a cross-sectional observational study of 265 newly diagnosed HIV-1 positive migrants, who were defined as individuals born outside Portugal. This group of people were part of the BESTHOPE study that was developed in 17 Portuguese hospitals between September 2014 and December 2019, and included information collected through sociodemographic and behavioral questionnaires filled in by the migrant patients, clinical questionnaires filled in by the clinicians and HIV-1 genomic sequences generated through resistance testing (Sanger sequencing). A multivariable statistical analysis was used to analyze the association between sociodemographic characteristics, sexual behaviors, HIV testing and sexual infections. Results: Most HIV-1 positive individuals included in the study were men (66.8%) and aged between 25 and 44 years old (59.9%). Men had a higher proportion of STIs when compared to women (40.4% vs. 14.0%) and the majority of men reported homosexual contacts (52.0%). Most men reported having had two or more occasional sexual partners in the previous year (88.8%) and 50.9% reported always using condoms with occasional partners, while 13.2% never used it. For regular partners, only 29.5% of the women reported using condoms, compared to 47.3% of men. Other risk behaviors for acquiring HIV, such as tattooing and performing invasive medical procedures, were more prevalent in men (38.0% and 46.2%, respectively), when compared to women (30.4% and 45.1% respectively) and 4.7% of men reported having already shared injectable materials, with no data for comparison in the case for women. Additionally, 23.9% of women reported having had a blood transfusion while only 10.3% of men reported having had this medical procedure. Meanwhile, 30.9% of the individuals reported having been diagnosed with some type of STI in the last 12 months. In addition, 43.3% of individuals that answered a question about hepatitis reported to be infected with hepatitis B, while 13.0% reported having hepatitis C infection. According to the multivariable analysis, the only transmission route was significantly associated with reports of previous STI infection: men who have sex with men (MSM) were 70% more likely to have been diagnosed with an STI in the past 12 months compared to the heterosexual route. Conclusion: HIV-1 infected men were more likely to report previous STIs than women. On the other hand, most migrant women had a regular sexual partner and never or only sometimes used condoms. This somewhat discrepant findings suggest that gender inequalities may make women unable to negotiate safe sexual practices, resulting in increased susceptibility to infection. However, since migrant women report less STIs, we cannot exclude that these STIs may remain undiagnosed. The implementation of safer sex awareness campaigns for condom use and screening for STIs in women is crucial. On the other hand, health education campaigns for STI knowledge need to be implemented for both MSM and women and their partners.
Journal Article
Pd Trinuclear Chelates with Spermidine: Selective Anticancer Activity towards TNBC-Sensitive and -Resistant to Cisplatin
by
Ramos, Raquel
,
Duarte, Sara Gomes
,
Diniz, Carmen
in
Antimitotic agents
,
Antineoplastic agents
,
Chemical properties
2023
Triple-negative breast cancer (TNBC) is one of the most aggressive forms of breast cancer and constitutes 10–20% of all breast cancer cases. Even though platinum-based drugs such as cisplatin and carboplatin are effective in TNBC patients, their toxicity and development of cancer drug resistance often hamper their clinical use. Hence, novel drug entities with improved tolerability and selectivity profiles, as well as the ability to surpass resistance, are needed. The current study focuses on Pd(II) and Pt(II) trinuclear chelates with spermidine (Pd[sub.3] Spd[sub.2] and Pt[sub.3] Spd[sub.2] ) for evaluating their antineoplastic activity having been assessed towards (i) cisplatin-resistant TNBC cells (MDA-MB-231/R), (ii) cisplatin-sensitive TNBC cells (MDA-MB-231) and (iii) non-cancerous human breast cells (MCF-12A, to assess the cancer selectivity/selectivity index). Additionally, the complexes’ ability to overcome acquired resistance (resistance index) was determined. This study revealed that Pd[sub.3] Spd[sub.2] activity greatly exceeds that displayed by its Pt analog. In addition, Pd[sub.3] Spd[sub.2] evidenced a similar antiproliferative activity in both sensitive and resistant TNBC cells (IC[sub.50] values 4.65–8.99 µM and 9.24–13.34 µM, respectively), with a resistance index lower than 2.3. Moreover, this Pd compound showed a promising selectivity index ratio: >6.28 for MDA-MB-231 cells and >4.59 for MDA-MB-231/R cells. Altogether, the data presently gathered reveal Pd[sub.3] Spd[sub.2] as a new, promising metal-based anticancer agent, which should be further explored for the treatment of TNBC and its cisplatin-resistant forms.
Journal Article