Publications by authors named "Helena Marcelino"
Article Synopsis
- Gliomas are aggressive brain tumors with poor prognosis, leading to the search for new therapies like resveratrol, which has shown promise in preclinical studies but yielded mixed results due to varying conditions.
- A recent meta-analysis reviewed ten studies from May 2023 on resveratrol's effects in murine glioma models, finding that it significantly reduced tumor volume compared to untreated groups.
- The study concluded that resveratrol is effective in slowing tumor growth in animal models and works better when combined with the drug temozolomide, while addressing concerns about publication bias.
Correction to: Effects of bisphenol A on human umbilical arteries.
Environ Sci Pollut Res Int
February 2023
Article Synopsis
- Bisphenol A (BPA) is an endocrine disruptor found in many plastic products, and this study investigates its effects on human umbilical artery contractility and related protein expressions.
- The research found that BPA acts as a vasodilator in human umbilical arteries, with its effects increasing with higher concentrations, and alters the expression of several key proteins involved in vascular function.
- Specifically, BPA exposure decreases certain calcium channel expressions and proteins associated with vasodilation while increasing others, highlighting the need for further research on the implications of BPA on vascular health.
Article Synopsis
- Glioblastoma (GBM) is the most common primary brain tumor, with hypoxic regions promoting tumor growth through the accumulation of adenosine, which influences cell proliferation and survival.
- * In experiments, adenosine significantly decreased viability in human astrocytes (HA) but had no effect on GBM cell lines, suggesting GBM cells adapt to high adenosine levels.
- * The use of an adenosine kinase inhibitor reduced proliferation in both HA and GBM cells, indicating that GBM cells have a mechanism to counteract the effects of adenosine, driving their adaptation and resistance.
Article Synopsis
- Catch-up growth is linked to increased risks of obesity and type 2 diabetes, characterized by fat deposition, hyperinsulinemia, and glucose intolerance.
- The study tested how refeeding on diets high in essential polyunsaturated fatty acids (ePUFA) affects insulin sensitivity and glucose control in rats previously calorie-restricted.
- Results showed that while a high-fat ePUFA diet prevented fat increase and insulin spikes, it only slightly improved insulin sensitivity, suggesting its benefits in glucose management during catch-up growth may not heavily rely on enhanced insulin action.
Article Synopsis
- Glioblastoma multiforme (GBM) is a highly aggressive brain tumor with a poor prognosis, prompting the need for alternative therapies like cannabinoids.
- A systematic review of animal studies on cannabinoids and GBM showed that cannabinoid therapy significantly reduced tumor growth in murine models.
- The analysis included nine publications and found cannabinoids to be effective across various types and treatment durations, even when accounting for publication bias.
Article Synopsis
- - Brain adenosine levels increase in stress conditions like strokes and tumors, which may influence cell proliferation and contribute to diseases such as neurodegeneration and glioma.
- - In a study, treating human astrocytes with 30 µM adenosine decreased their viability by 40%, an effect that could be reversed by adenosine deaminase but not by blocking adenosine receptors.
- - The combination of adenosine and 100 µM homocysteine resulted in a significant 76% reduction in astrocyte proliferation, indicating a complex interaction, and suggesting adenosine's effects may involve a receptor-independent mechanism related to SAH hydrolase.
Article Synopsis
- * Using organ bath techniques, the researchers found that TBT causes both short-term relaxation and long-term impairment of contractile capacity in the artery when exposed to 5-HT and histamine.
- * Long-term TBT exposure led to a decrease in gene expression levels of 5-HT2A and H1 receptors, indicating that TBT alters both the activity and expression of these important vascular receptors.
Article Synopsis
- Testosterone (T) significantly impacts the structure and function of the hippocampus (HP), but the specific genes and mechanisms involved are not fully understood.
- An analysis of the transcriptome in orchidectomized (OOX) rats revealed 271 genes that are differentially expressed when comparing OOX and control (sham) animals.
- Results indicated that T depletion led to the upregulation of 98 genes linked to neurogenesis and behavior, while 173 genes related to signal transduction and neurological processes were downregulated, highlighting profound changes in hippocampal gene expression due to low testosterone levels.
Article Synopsis
- - The choroid plexus (CP) is a crucial structure in the brain responsible for producing cerebrospinal fluid (CSF) and acts as a barrier between blood and CSF.
- - Research indicates that sex hormones play a neuroprotective role and may influence gene expression in the CP, especially after gonadectomy (removal of gonads) in rats.
- - A study found significant changes in over 3,000 genes in the CP of male and female rats post-gonadectomy, highlighting the importance of sex hormones in various biological pathways related to CP functions and maintaining CSF balance.
Article Synopsis
- Catch-up growth, linked to increased risk of type 2 diabetes, is marked by high insulin levels and rapid fat recovery following periods of food restriction.
- In a rat study, refeeding on a high-fat diet was found to reduce the ability of adipose tissue to utilize glucose for fat production (de novo lipogenesis), leading to potential issues with glucose regulation.
- The research supports the idea that dietary fats can disrupt normal glucose handling by promoting insulin resistance in muscles and reducing fat storage capabilities in fat tissue, contributing to glucose intolerance during catch-up growth.
Article Synopsis
- The study explores how different types of polyunsaturated fatty acids (PUFAs) affect fat accumulation and insulin levels during growth spurts on high-fat diets.
- Rats fed diets high in linoleic acid (LA) or α-linolenic acid (ALA) showed better insulin sensitivity and lower fat mass when compared to those on low PUFA diets.
- The research suggests that consuming PUFAs as 25-30% of energy intake can significantly improve body composition and insulin sensitivity, highlighting the benefits of LA and ALA over other fatty acids like arachidonic acid (AA) and DHA.
Article Synopsis
- The study focuses on "catch-up growth," a process linked to an increased risk of type 2 diabetes, particularly examining how glucose is used by fat cells during this phase.
- Researchers used a rat model that simulates semistarvation followed by refeeding to study changes in fat tissue and glucose metabolism without increased food intake.
- Results indicated that during catch-up fat, fat cells increase in number and change in composition, while hyperinsulinemia and enhanced fat-making processes (lipogenesis) occur early, suggesting these changes are crucial for storing glucose in fat rather than muscle.
Article Synopsis
- New monomethine cyanine dyes were created using quinoline and benzothiazole and analyzed with various techniques like NMR and spectroscopy.
- These dyes, which include amino and acetamido groups, were synthesized through the reaction of p-toluenesulfonate heterocyclic salts, resulting in iodide, bromide, and tosylate forms.
- When tested as DNA stains in electrophoretic gels, the acetamido group and bromide counteranion showed better sensitivity compared to amine groups and other counteranions, similar to ethidium bromide detection at low DNA concentrations (1-3 ng).