Laura Maifrino | Universidade São Judas Tadeu (original) (raw)

Papers by Laura Maifrino

Experimental Parasitology, 2005

In this paper, the distribution of NADH-positive and somatostatin (SOM) immunoreactive neurons in... more In this paper, the distribution of NADH-positive and somatostatin (SOM) immunoreactive neurons in the myenteric plexus of the colon of mice infected with Trypanosoma cruzi was studied. Ten young, male, BALB/c mice were inoculated with the Y strain of T. cruzi, 60 days previously (chronic phase of the infection). Another 10 mice were uninfected controls. Distal and proximal colonic neurons from Wve chronically infected mice and their controls were stained using the NADH-diaphorase method. Quantitative results showed a signiWcant decrease of 39% in the number of neurons in the proximal colon of infected mice and 58% in the distal colon (p < 0.05). SOM was localized in Wve animals from each group by light microscopy, using an indirect immunoXuorescence technique. It was observed that there were far fewer nerve cells and Wbres and less intensely stained neuron bodies and varicose SOM-positive nerve Wbres in both, control and chronic infected mice. These Wndings could be related to the disturbances in intestinal motility observed in patients in the chronic phase of Chagas' disease.  2005 Elsevier Inc. All rights reserved.

Annals of Tropical Medicine & Parasitology, 2002

The neuronal features of the hearts of mice that were acutely or chronically infected with the Y ... more The neuronal features of the hearts of mice that were acutely or chronically infected with the Y strain of Trypanosoma cruzi were compared with those of control hearts from uninfected mice. Whole-mount preparations of the murine atria, isolated by microdissection, were stained to reveal neurons with NADH-diaphorase activity. Counts, by a microscopist who was blind to the infection status of the donor mouse, revealed that there were significantly (38%) fewer such neurons in the atria from the acutely infected mice than in the atria from the control hearts. The ganglia of the infected mice were also irregularly distributed, severely damaged ganglia being found beside slightly degenerated or morphologically normal ones. Although the ganglia contained small, medium and large neurons, the apparent destruction caused by T. cruzi was confined to the large ones. As neuron counts in preparations of hearts from mice with chronic infections were 32% lower than those in the control hearts, there appears to be no additional loss of cardiac neurons as the acute infection in mice progresses to the chronic phase.

Braz J Morphol Sci, Jun 1, 2012

Several studies indicate that the estrogen deficiency increase the incidence of the cardiovascula... more Several studies indicate that the estrogen deficiency increase the incidence of the cardiovascular diseases in women in post-menopausal period and that the exercise program may prevent or relieve problems such as cardiovascular disease, obesity, muscle weakness, osteoporosis and depression. The effects of the estrogen deprivation in the myocardium still remain unclear, mainly in the right ventricle. The aim was to investigate the effects of exercises on the right myocardium in the female mice subjected to deprivation of ovarian hormones. Material and methods: A total of 15 female mice at 9 months of age, divided into 3 groups (n = 5) were studied: non-ovariectomized sedentary (S); ovariectomized sedentary (OS), ovariectomized trained (OT) animals. Ovariectomy was performed at 9 months of age and physical training began 7 days after surgery. The animals underwent a physical training protocol for 4 weeks on a treadmill with progressive speed and load (one hour a day/5 days a week at 50 to 65% of the maximum speed of running). After the experimental proceeding, the heart were removed and processed accordingly to conventional protocol for optical microscopy, and the slides stained by the methods of Hematoxylin and Eosin Stereology was used to analyze the components of the myocardium. Results: Ours results indicate that the exercise training promoted cardiomyocyte hypertrophy, increase in connective tissue with decreased cardiomyocytes. Conclusion: Our data suggest that moderate exercise promoted right ventricular remodeling with cardiomyocyte hypertrophy and increase in connective tissue, to fit the modifications promoted by exercise in the left ventricle.

Motriz: Revista de Educação Física, 2015

International Archives of Medicine, 2014

The aging male : the official journal of the International Society for the Study of the Aging Male, 2014

Changes in the heart compartments that leads to pathological cardiac hypertrophy can be related t... more Changes in the heart compartments that leads to pathological cardiac hypertrophy can be related to testosterone reduction in aging males since heart cells are susceptible to androgens. Resistance exercise delays the changes of aging. This study aimed to analyze alterations of the left ventricle of aged rats subjected to resistance exercise with administration of testosterone. Wistar rats were divided into five groups: C Group (control), S Group (sedentary), ST Group (sedentary treated with testosterone), T Group (trained) and TT Group (trained and treated with testosterone), strength training protocol and testosterone treatment were 16 weeks long. All groups were sacrificed at 16 months except for C group, sacrificed at 13 months. There was no change in the weight of the heart or the left ventricle between the groups. ST group showed increase in Nv [cap] density of capillaries and collagen, with no differences in interstitial space. Both trained groups (T and TT) showed increase in ...

The Aging Male, 2014

Physical inactivity, diabetes, hypertension, dyslipidemia, smoking and obesity were associated wi... more Physical inactivity, diabetes, hypertension, dyslipidemia, smoking and obesity were associated with imbalance in oxidative stress, leading to endothelial dysfunction. Such dysfunction is present in both cardiovascular disease (CVD) and erectile dysfunction (ED). ED is the persistent inability to achieve or sustain an erection sufficient for satisfactory sexual performance and is one of the first manifestations of endothelial damage in men with CVD risk factors. The purpose of this article is to review the results of studies involving physical activity, CVD, endothelial dysfunction and ED in order to verify its applicability for improving the health and quality of life of men with such disorders. There is consistent evidence that endothelial damage is intimately linked to ED, and this manifestation seems to be associated with the appearance CVDs. On the other hand, physical activity has been pointed out as an important clinical strategy in the prevention and treatment of CVDs and ED mainly associated with improvement of endothelial function. However, further experimental and clinical prospective investigations are needed to test the role of physical exercises in the modulation of endothelial function and their implications on erectile function and the appearance of CVDs.

Memórias do Instituto Oswaldo Cruz, 1999

Brazilian Journal of Medical and Biological Research, 2000

In the present study we investigated the effect of salt intake on myenteric neuron size of the co... more In the present study we investigated the effect of salt intake on myenteric neuron size of the colon of adult male Wistar rats. The animals were placed on either a high-salt (HS; 8%; 12 animals) or a low-salt diet (LS; 0.15%; 12 animals) for 15 or 52 weeks and blood pressure was measured. The sizes of myenteric neurons of the distal colon from both groups were measured. No difference in neuron size was observed between the HS and LS groups after 15 weeks. After 52 weeks on HS, neuron size was increased (P<0.005) when compared with the LS group. The rats also presented hypertension, which was significantly different at 52 weeks (142 ± 11 vs 119 ± 7 mmHg). These results suggest that a long time on an HS diet can significantly increase myenteric nerve cell size.

Brazilian Journal of Medical and Biological Research, 1997

The myenteric plexus of the digestive tract of the wild mouse Calomys callosus was examined using... more The myenteric plexus of the digestive tract of the wild mouse Calomys callosus was examined using a histochemical method that selectively stains nerve cells, and the acetylcholinesterase (AChE) histochemical technique in whole-mount preparations. Neuronal density was 1,500 +/- 116 neurons/cm2 (mean +/- SEM) in the esophagus, 8,900 +/- 1,518 in the stomach, 9,000 +/- 711 in the jejunum and 13,100 +/- 2,089 in the colon. The difference in neuronal density between the esophagus and other regions was statistically significant. The neuron profile area ranged from 45 to 1,100 microns2. The difference in nerve cell size between the jejunum and other regions was statistically significant. AChE-positive nerve fibers were distributed within the myenteric plexus which is formed by a primary meshwork of large nerve bundles and a secondary meshwork of finer nerve bundles. Most of the nerve cells displayed AChE activity in the cytoplasm of different reaction intensities. These results are important in order to understand the changes occurring in the myenteric plexus in experimental Chagas' disease.

Annals of Tropical Medicine And Parasitology, 1999

The distribution of a tachykinin (substance P) and vasoactive intestinal peptide (VIP) and the nu... more The distribution of a tachykinin (substance P) and vasoactive intestinal peptide (VIP) and the number and morphology of the large granular vesicles (LGV) in the myenteric plexus of the colons of mice were investigated. Six of the 12 young, male, Swiss mice studied had been inoculated with the Y strain of Trypanosoma cruzi 2 months previously whereas the others were uninfected controls. Substance P (SP) and VIP were localized by light microscopy, using an immunohistochemical method, and LGV were counted in sections studied by electron microscopy. There were far fewer LGV and less intensely staining varicose VIP- and SP-positive nerve fibres in the infected mice than in the controls. Denervation of the myenteric plexus may decrease the content of tachykinins (TK) and VIP in animals infected with T. cruzi. Such reduction in TK and VIP activity could be related to the disturbances in intestinal motility observed in the chronic phase of Chagas disease.

Anais da Academia Brasileira de Ciências, 2013

Estrogen deprivation in postmenopausal women increases cardiovascular risk. Cardiovascular risk a... more Estrogen deprivation in postmenopausal women increases cardiovascular risk. Cardiovascular risk as a result of atherosclerosis is able to induce an inflammatory disease as far as cyclooxygenase-2 (COx-2) expression. The purpose of the study was to investigate the role of COx-2 on exercise training in female mice low-density lipoprotein receptor knockout (LdL-KO) with or without ovariectomy. A total of 15 female C57BL/6 mice and 15 female LdL-KO mice were distributed into 6 groups: sedentary control, sedentary control ovariectomized, trained control ovariectomized, LdL-KO sedentary, LdL-KO sedentary ovariectomized and LdL-KO trained ovariectomized. The ascending part of the aorta was stained with h&E and COx-2 expression was assessed by immunohistochemistry. Results revealed that ovariectomy as well as exercise training were not able to induce histopathological changes in mouse aorta for all groups investigated. LdL-KO mice demonstrated plaque containing cholesterol clefts, foamy histiocytes and mild inflammatory process for all groups indistinctly. Ovariectomy induced a strong immunoexpression in atherosclerosis lesion of LdL-KO mice. Nevertheless, a down-regulation of COx-2 expression was detected in LdL-KO trained ovariectomized when compared to LdL-KO sedentary. Our results are consistent with the notion that exercise training is able to modulate COx-2 expression in LdL-KO mice as a result of COx-2 down-regulation.

Oxidative Medicine and Cellular Longevity, 2016

Introduction. Sarcopenia is a process characterized by reduction in protein mass and muscle stren... more Introduction. Sarcopenia is a process characterized by reduction in protein mass and muscle strength with increasing age, especially in the postmenopausal period, resulting in functional limitations and with great impact on the physical autonomy of the elderly. Objective. To evaluate the effects of diets with vegetable proteins (VP) or animal proteins (AP) associated with resistance training (RT) on the structural and biochemical parameters of the medial gastrocnemius muscle in Wistar rats with sarcopenia. Methods. An experimental model with ovariectomized rats was used to induce sarcopenia and resistance training. The histochemical technique was used for the typing of muscle fibers, the cross-sectional area of myocytes, and volume densities of myocytes and interstitium; the technique of Picrosirius stain was used to highlight the collagen fibers. Results. The VP diet was not able to minimize the effects of sarcopenia in the medial gastrocnemius of sedentary animals and when associated with RT, it promoted maintenance of the CSA, attenuating the atrophy of type IIB fibers in the medial gastrocnemius. The AP diet in sedentary animals protected the type I fibers. When combined with RT, the AP promoted muscle remodeling, with reduction in volume density of type I and IIA fibers, and increase of IIB fibers, together with an increase in collagen volume density. Conclusion. The data suggest a tendency to better results of hypertrophy in animal groups that consumed the AP diet, even the sedentary animals, although more evident in those trained.

Biologics: Targets and Therapy, 2015

Chronic chagasic heart disease represents extensive remodeling of the cardiovascular system, mani... more Chronic chagasic heart disease represents extensive remodeling of the cardiovascular system, manifested as cardiac denervation, interstitial mononuclear infiltrate, myocyte and vascular degenerative changes, fibrosis, and hypertrophy. Moreover, aerobic exercises are widely indicated for the treatment of various disorders of the cardiovascular system. To evaluate the right and left ventricles of BALB/c mice with chronic Chagas disease, undergoing mild exercise, by using morphometric and stereological methods. A total of 20 male mice at 4 months of age were used for experiments. The animals were divided into four groups (n=5 in each group): untrained control, trained control, untrained infected (UI), and trained infected (TI). Animals of UI and TI groups were inoculated with 1,000 trypomastigote forms of Trypanosoma cruzi (Y strain), and after 40 days, animals entered chronic phase of the disease. Physical exercise, which included swimming, was performed for 30 minutes daily, five times a week for 8 consecutive weeks at a bath temperature of 30°C. After the trial period, euthanasia and subsequent withdrawal of the heart were done. The organ was prepared by histological staining procedures with hematoxylin-eosin and picrosirius red. We found that the physical training used in our experimental model promoted increase in volume density of capillaries and decrease in volume density of collagen fibers and cross-sectional area of cardiomyocytes in chagasic animals (TI group). By histopathological analysis, we found differences in the inflammatory infiltrate, which was lower in animals of TI group. The training program promoted a recovery of these parameters in the TI group. Our results suggest that low-intensity aerobic exercise acts on morphological and morphometric parameters of the left and right ventricles in mice infected with T. cruzi, reducing the changes caused by the organism and making the results comparable to those of the uninfected control group.

World Journal of Gastroenterology

To evaluate the effects of protein deprivation on the myenteric plexus of the esophagus of weanli... more To evaluate the effects of protein deprivation on the myenteric plexus of the esophagus of weanling rats. Pregnant female Wistar rats were divided into 2 groups: nourished (N), receiving normal diet, and undernourished (D), receiving a protein-deprived diet, which continued after birth. At twenty-one days of age, 13 esophagi from each group were submitted to light microscopy and morphometrical analysis employing the NADH diaphorase, NADPH diaphorase and acetylcholinesterase techniques. Three other esophagi from each group were evaluated with transmission electron microscopy (TEM). In both the NADH- and the NADPH-reactive mounts, the neurons of the N mounts were more intensely stained, while in the D esophagi only the larger neurons were reactive. Many myenteric neurons of N were intensely reactive for AChE activity but only a few neurons of D exhibited these aspects. Ultrastructural analysis revealed that the granular reticulum of N showed large numbers of ribosomes aligned on the o...

World journal of gastroenterology : WJG, Jan 14, 2007

BMC neuroscience, 2006

The present study was conducted to determine the location, the morphology and distribution of NAD... more The present study was conducted to determine the location, the morphology and distribution of NADPH-diaphorase positive neurons in the cardiac nerve plexus of the atria of mice (ASn). This plexus lies over the muscular layer of the atria, dorsal to the muscle itself, in the connective tissue of the subepicardium. NADPH- diaphorase staining was performed on whole-mount preparations of the atria mice. For descriptive purposes, all data are presented as means +/- SEM. The majority of the NADPH-diaphorase positive neurons were observed in the ganglia of the plexus. A few single neurons were also observed. The number of NADPH-d positive neurons was 57 +/- 4 (ranging from 39 to 79 neurons). The ganglion neurons were located in 3 distinct groups: (1) in the region situated cranial to the pulmonary veins, (2) caudally to the pulmonary veins, and (3) in the atrial groove. The largest group of neurons was located cranially to the pulmonary veins (66.7%). Three morphological types of NADPH-dia...