Vânia Maria Moraes Ferreira

Mechanisms involved in the antinociception caused by ethanolic extract obtained from the leaves of Melissa officinalis (lemon balm) in mice

The present study examined the antinociceptive effect of the ethanolic extract from Melissa officinalis L. and of the rosmarinic acid in chemical behavioral models of nociception and investigates some of the mechanisms underlying this effect. The extract (3-1000 mg/kg), given orally (p.o.) 1 h prior to testing, produced dose-dependent inhibition of acetic acid-induced visceral pain, with ID50 value of 241.9 mg/kg. In the formalin test, the extract (30-1000 mg/kg, p.o.) also caused significant inhibition of both, the early (neurogenic pain) and the late (inflammatory pain), phases of formalin-induced licking. The extract (10-1000 mg/kg, p.o.) also caused significant and dose-dependent inhibition of glutamate-induced pain, with ID50 value of 198.5 mg/kg. Furthermore, the rosmarinic acid (0.3-3 mg/kg), given p.o. 1 h prior, produced dose-related inhibition of glutamate-induced pain, with ID50 value of 2.64 mg/kg. The antinociception caused by the extract (100 mg/kg, p.o.) in the glutamate test was significantly attenuated by intraperitoneal (i.p.) treatment of mice with atropine (1 mg/kg), mecamylamine (2 mg/kg) or l-arginine (40 mg/kg). In contrast, the extract (100 mg/kg, p.o.) antinociception was not affected by i.p. treatment with naloxone (1 mg/kg) or D-arginine (40 mg/kg). It was also not associated with non-specific effects, such as muscle relaxation or sedation. Collectively, the present results suggest that the extract produced dose-related antinociception in several models of chemical pain through mechanisms that involved cholinergic systems (i.e. through muscarinic and nicotinic acetylcholine receptors) and the L-arginine-nitric oxide pathway. In addition, the rosmarinic acid contained in this plant appears to contribute for the antinociceptive property of the extract. Moreover, the antinociceptive action demonstrated in the present study supports, at least partly, the ethnomedical uses of this plant.

Behavioral and biochemical effects of neonicotinoid thiamethoxam on the cholinergic system in rats.

Thiamethoxam is a neonicotinoid insecticide, a group of pesticides that acts selectively on insect nicotinic acetylcholine receptors (nAChRs), with only a little action on mammalian nAChRs. Nevertheless, the selectivity of neonicotinoids for the insect nAChRs may change when these substances are metabolized. Therefore, we aimed to determine the potential effects of thiamethoxam on mammalian brain, testing the performance in the open field and elevated plus-maze of rats exposed to this insecticide and, in order to establish the neurochemical endpoints, we measured the acetylcholinesterase activity in different brain regions (hippocampus, striatum and cortex) and the high-affinity choline uptake (HACU) in synaptosomes from rat hippocampus. Treated animals received thiamethoxam (25, 50 or 100mg/kg) for 7 consecutive days. The results showed that treatment with thiamethoxam induced an increase in the anxiety behavior at two doses (50 or 100mg/kg). Moreover, there was a significant decrease in both HACU and acetylcholinesterase activity. Our hypothesis is that thiamethoxam (or its metabolites) could be acting on the central rats nAChRs. This would produce an alteration on the cholinergic transmission, modulating the anxiety behavior, acetylcholinesterase levels and HACU.

Does metoclopramide impair anastomotic healing of the left colon of rats

PURPOSE To evaluate the effects of metoclopramide on the formation of adhesion and the healing of left colonic anastomoses in rats. METHODS Forty rats underwent sectioning of the left colon and end-to-end anastomosis and were divided into two groups of 20 animals for the administration of metoclopramide (experimental group - E) or saline solution (control group - C). Each group was divided into subgroups of 10 animals each to be killed on the third (E3 and C3) or seventh postoperative day (E7 and C7). Adhesion was assessed, and a colonic segment containing the anastomosis was removed for analysis of breaking strength and hydroxyproline concentration. RESULTS There were no deaths or dehiscence on the 3(rd) postoperative day. There was one death and one blocked anastomotic dehiscence in the E7 group. No significant differences between groups were found in the analysis of clinical outcome, intra-cavity adhesion, adhesion to the anastomosis or breaking strength on the 3(rd) and 7(th) postoperative day. Hydroxyproline concentration was higher in the control group on the 3(rd) (p=0.006) but not on the 7(th) postoperative day (p=0.241). CONCLUSION Metoclopramide did not have harmful effects on the healing of intestinal anastomoses in rats.

Study on adhesion formation and the healing of colon anastomosis in rats with induced peritoneal sepsis

PURPOSE To evaluate the effects of abdominal sepsis on adhesion formation and colon anastomosis healing in rats. METHODS Forty rats were distributed in two groups containing 20 rats each for left colon anastomosis in the presence (Group S) or absence (Group N) of induced sepsis by cecal ligation and puncture. Each group was divided into subgroups for euthanasia on the third (N3 and S3) or seventh (N7 or S7) post-operative day. The amount of adhesions was evaluated and a segment of the colon was removed for histopathologic analysis, bursting strength assessment, hydroxyproline and the determination of tissue collagen. RESULTS The subjects which underwent cecal ligation and puncture presented a higher amount of intra-abdominal adherences in both third (p=0,00) and seventh (p=0,00) post-operatory days. Smaller bursting strengths were found in the S3 subgroup, and greater bursting strengths were found in the S7 subgroup. There was no difference in the variations on the concentrations of hydroxyproline, tissue collagen and histopathology. CONCLUSIONS The peritoneal infection which was developed by cecal ligation and puncture raised the amount of intra-cavitary adhesions. There was a decrease in the amount of colonic anastomosis on the third post-operatory day with a following raise on the seventh without any effects on other healing parameters.

Adult brain nitrergic activity after concomitant prenatal exposure to ethanol and methyl mercury

Pregnant rats were exposed to ethanol (EtOH) and/or methyl mercury (MeHg) during fetal brain development. Nitrergic activity was quantified by densitometric measurement of formazan deposits in the hippocampus, cerebellum and striatum of two-month-old offspring following histochemical assay for NADPH-diaphorase (NADPH-d) activity. Compared to control subjects, an increase in nitrergic activity was found in the molecular layer of dentate gyrus and in the lacunosum molecular and stratum radiatum of CA1 (cornus amoni 1) in the EtOH+MeHg group, whereas a single administration of EtOH increased the activity in all striatal segments. The cerebellum seems to be less sensitive at this time-point to intoxication, and presented an increase only at the molecular layer of EtOH-exposed animals when compared to the MeHg and EtOH+MeHg groups (ANOVA, one-way followed by Tukeys test, p<0.05 or p<0.01). Taken together, results suggest that developmental exposure to EtOH and MeHg, singularly or in combination, alters nitrergic activity in adult rat in different ways depending on the region and layer of the central nervous system (CNS), and that these alterations might be related to different local metabolic properties.

The effect of simvastatin on relapse of tooth movement and bone mineral density in rats measured by a new method using microtomography

PURPOSE To evaluate the effect of simvastatin on relapse of tooth movement in rats using microtomography (micro CT), as well as the correlation of bone density with the orthodontic relapse. METHODS Twenty-five adult male Wistar rats, divided into two groups, had stainless steel springs installed on left maxillary first molar. The molars were moved for 18 days, and after removing the springs, were applied by oral gavage, 5mg/kg of simvastatin in the experimental group for 20 days. Tooth relapse was assessed with a micro CT scanner, and the images chosen through the Data Viewer software 1.5.0.0 had their measurement guides made and checked by the software Image ProR plus 5.1, and compared by Mann-Whitney test. After rats were sacrificed, bone mineral density was evaluated by micro CT through the software CT Analyzer 1.13 and compared by independent T-test, as well as by Spearman correlation test. RESULTS Relapse and bone mineral density (BMD) was lower in the experimental group than in the control group, however without a statistically significant difference. CONCLUSION Simvastatin did not inhibit the relapse of tooth movement in rats, and there was no correlation between bone density and orthodontic relapse.

Efeitos da bromoprida na cicatrização de anastomoses no cólon esquerdo de ratos

OBJECTIVE To evaluate the effects of bromopride on the formation of adhesions and anastomotic healing in the left colon of rats. METHODS We divided 40 rats into two groups of 20 animals, administration of bromopride (study group-E) or saline (control group-C). Each group was divided into subgroups containing 10 animals each for euthanasia in the third (C3 and E3) or the seventh (E7 and C7) postoperative days. The rats were submitted to section of the left colon and end-to-end anastomosis. On the day of reoperation, we evaluated the total amount of adhesions and removed a colonic segment containing the anastomosis for histopathological analysis, assessment of rupture strength and hydroxyproline concentration. RESULTS There was no difference between groups in relation to clinical outcome. Two animals in the study group had blocked anastomotic leakage. The animals that received bromopride had the number of intracavitary adhesions and adhesions to the anastomosis similar to the control group. The anastomoses from the group E3 animals showed lower resistance to rupture the one from the C3 group (p = 0.04). This effect did not occur on the seventh postoperative day (p = 0.37). There was no significant difference between groups in relation to histopathology and hydroxyproline concentration in the anastomoses. CONCLUSION The use of bromopride was associated with decreased tensile strength of left colon anastomosis in rats in the third postoperative day.

Aerobic bacteria on cervical cytology

Dysbacteriosis is characterized by a shift in the microbiota, with a decrease in the amount of lactobacilli accompanied by an increase of anaerobic and/or aerobic bacteria. The infections of the genital tract by aerobic bacteria are associated with aerobic vaginitis (AV), pelvic inflammatory disease, infertility and pregnancy complications, such as chorioamnionitis, premature rupture of membranes and preterm delivery. Universal screening for group B streptococcus (GBS) at 35 to 37 weeks’ gestation is recommended in all pregnant women. Besides this, cervical colonization by aerobic bacteria is an independent and significant factor in the determination of success in assisted reproduction treatments. Dysbacteriosis may also serve to identify groups of patients with an increased risk for a smear with squamous abnormalities. Because of the poor recognition of AV, this condition is often misdiagnosed as bacterial vaginosis (BV). AV and BV may have similar symptoms, such as increased vaginal discharge, a deficiency in lactobacilli and an elevated pH. However, the abnormal microbiota in BV is anaerobic (Gardnerella vaginalis, Mobiluncus sp., Bacteroides sp., Prevotella sp., Peptostreptococcus sp., etc.), while in AV only aerobic enteric bacteria, such as Escherichia coli, Staphylococcus aureus, GBS and enterococci, are recovered. Samples for both conventional cervical cytology and culture of aerobic bacteria were collected from women who underwent annual routine screening. The bacterial microbiota on cervical cytology samples was analyzed in 47 samples with positive culture. For culture, an endocervical swab was taken and immediately placed in Stuart medium. Culture was performed on blood agar, chocolate agar, and MacConkey agar, and incubated at 35–378 for 24–48 hours. VITEK 2 grampositiveGP ID and gram-negative GN ID cards (bioM erieux, Marcy l’ Etoile, France), based on colorimetric detection, were used for identification of bacteria according to the manufacturer’s instructions. The samples for conventional cervical cytology were collected from ectocervix and endocervix with Ayre’s spatula and cytobrush, respectively. The smears were immediately fixed in 95% ethanol and stained by the Papanicolaou method. Individual squamous cells with a layer of coccobacilli along the margins of the cell membranes were considered “clue cells.” Coccobacilli, characterized by small bacilli and cocci organisms, were found both isolated and as microcolonies. Lactobacilli were characterized by the presence of elongated bacillary structures. The smears were analyzed by one pathologist who was blinded to the culture

A panel of markers for identification of malignant and non-malignant cells in culture from effusions

The aim of the present study was to identify cell types in primary culture from malignant and non-malignant effusions. Effusion samples were subjected to cytology and culture. Immunocytochemistry was performed in cytological slides to evaluate malignancy (positivity for malignancy markers) and in culture slides for identification of cell types in growth. A total of 143 effusion samples (pleural n=76; peritoneal n=37; pericardial n=4; and peritoneal lavage n=26) were analyzed. Cell growth was observed in 34.9% of all samples and immunocytochemistry for identification of cell types in culture slides was conclusive in 90% of them. In non-malignant samples (n=28), growth of mesothelial cells, macrophages and of both cell types was identified in 82.14, 10.71 and 7.14%, respectively. In malignant samples (n=17, all carcinomas), growth of malignant epithelial cells and of both malignant epithelial and mesothelial cells was identified in 41.17 and 23.52%, respectively. In the remaining 35.29% of malignant samples, the only cells in growth were mesothelial and/or macrophages instead of malignant epithelial cells. In conclusion, in culture of malignant effusions, mesothelial cells may be simultaneously identified with malignant epithelial cells. Besides, mesothelial cells and macrophages may be the only cells identified in malignant effusion culture. Therefore, a broad panel of cell markers should be used for unmistakable identification of cells in studies of effusion primary culture. The ideal malignant effusion sample to obtain culture of neoplastic cells should be that without the presence of mesothelial cells and macrophages.