Biomedical subjects

M C Pinheiro

Publications and source records attributed to M C Pinheiro.

10 recordsLinked to original sources

PubMed2005

Ultrastructural, immunohistochemical and biochemical analysis of glycosaminoglycans and proteoglycans in the mouse pubic symphysis during pregnancy.

During pregnancy, an interpubic ligament is formed in the mouse pubic symphysis. In late stages, this ligament undergoes "relaxation" to allow proper delivery, which is expected on the 19th day. Proteoglycans and hyaluronic acid play an important role in the remodeling of the extracellular matrix in these tissues. Glycosaminoglycans and proteoglycans were studied by electron microscopic, immunohistochemical and biochemical methods in samples of mouse pubic symphysis from the 12th to 18th day of pregnancy. At the ultrastructural level, using cuprolinic blue and enzymatic digestion by chondroitin lyases, two types of proteoglycan filaments were observed in the fibrocartilage on the 12th day, as well as in D 15, D 17 and D 18 pubic ligaments. The only sulfated glycosaminoglycan in these filaments was chondroitin sulfate, as shown by chondroitin lyase treatment. Their electrophoretic mobility, before and after enzymatic degradation, corroborated this inference. The ratio of chondroitin sulfate/dry weight of symphysis showed two phases of increase: between D12 and D 15, and between D 17 and D 18. We suggest that the first corresponds mainly to an increase in decorin when the ligament is formed, and the second to versican, during "relaxation". Versican and hyaluronic acid, working as water holding molecules would be responsible for the hydration of the ligament at the end of pregnancy, allowing an increase in resiliency. The presence of hyaluronic acid was confirmed by labeling with HA-probe in the perichondrium, fibrocartilage and ligament. The role of collagen fibers as physical restrictors of the complete expansion of glycosaminoglycans and hyaluronic acid in tissue is discussed.

Animals↗

PubMed2004

Histochemical and ultrastructural study of collagen fibers in mouse pubic symphysis during late pregnancy.

Reference is usually made to the parallel orientation towards the main line of exerted tension at the pubic joint in mice, for supporting forces applied to the joint. Despite the wealth of morphological information about the extracellular matrix in this joint, little is known regarding the involvement of the crimp of collagen fibers in the dramatic transformations occurring in this region during the last 3 days of pregnancy. Examination of the collagenous architecture suggests that the biomechanical properties are directly related to fibril diameters, composition of ground substance and changes in the bundle morphology, particularly in the crimp structure. The purpose of this study was to further describe the transformation of the collagen fibers of the pubic symphysis during late mouse pregnancy. We examined the architecture of collagen fibers in the symphysis and pubic ligament through the Picrosirius-polarization method and also through scanning electron microscopy to directly visualize and measure the crimping from pregnant and virgin mice. The crimp angle and the length of five consecutive crimps were measured according to Patterson-Kane et al. [Connect. Tissue Res. 36 (1997) 253]. It could be demonstrated that the angles progressively decreased and the crimp length increased, denoting that the fibers have untwisted during the relaxation process. Our findings suggest that a disruption of the helical arrangement of the collagen containing fibers may contribute to explaining the rapid remodeling that occurs at the end of pregnancy and that is responsible for an increase in pliancy and length of the pubic ligament in mice.

Animals↗

PubMed2001

Mercury pollution in the Tapajos River basin, Amazon: mercury level of head hair and health effects.

There is increasing concern about the potential neurotoxic effects of exposure to methylmercury for the 6 million people living in the Amazon, even in regions situated far away from the gold mines (garimpos), considered to be the major source of mercury pollution. In November 1998, a spot investigation on mercury contamination was conducted in three fishing villages (Barreiras, Rainha, and Sao Luiz do Tapajos) on the Tapajos River, an effluent of the Amazon, situated several hundred kilometers downstream from the gold-mining areas. A total of 132 fishermen and their families volunteered for the current study. As was anticipated, the total mercury levels in the head hair collected from the fishing villages were relatively high (14.1-20.8 ppm on the average) and the number of subjects with a high total mercury level over 10 ppm (the least upper bound of a normal value) was 103 (78.0%) in total, along with various symptoms, thereby suggesting wide mercury contamination in the Tapajos River basin. Moreover, in view of the absence of other diseases (e.g., alcoholism or malaria), a high intake of fish containing a methylmercury level, and high hair mercury levels in addition to the various symptoms such as sensory disturbance (especially glove-and-stocking type, which is characteristic of Minamata disease), tremor, failure in two-point discrimination, and slight balancing failure, several subjects examined were diagnosed with mild Minamata disease. The findings obtained suggest, thus, that the mercury pollution in the Amazon should be crucially observed for head hair mercury level and health in a much broader region.

Adolescent↗

PubMed1996

Transient expression of an atypical D1-like dopamine receptor system during avian retina differentiation.

Intact cultured retina cells from chick embryos at stage E9C5 (cultures initiated with retinae from 9-day old embryos followed by 5 days in culture), preincubated with 2 nM unlabelled SCH 23390 (R(+)-7- chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride) for 20 to 60 min at 37 degrees C and then washed 5 to 25 times (approximately 1.5 min/wash) with 2 ml SCH 23390-free medium, responded to dopamine with cAMP accumulation that corresponded to 30-50% of the dopamine-promoted cAMP accumulation observed in untreated cells or in cells exposed to the inactive isomer of SCH 23390. Therefore, 50 to 70% of the dopamine response of SCH 23390-pretreated cells was inhibited after extensive washings of the cultures. At E9C12 the fraction of the dopamine response that remained inhibited by SCH 23390 after the washings declined to 30% of the control cultures or the cultures exposed to the SCH 23390 enantiomer. Cultures at stage E9C5 treated with SCH 23390 followed by extensive washings as above and then used for measuring the number of [3H]-SCH 23390 specific binding sites revealed that 60% of the sites did not interact with the tritiated compound when compared to untreated cultures or to cultures preincubated with the inactive isomer of SCH 23390. When E9C12 cultures were subjected to the same experimental protocol less than 10% of D1-like sites did not interact with [3H]-SCH 23390 after the cells had been exposed to the unlabelled compound. Dissociated cells prepared from intact retinae obtained from 12-13-day old embryos also displayed a subpopulation of D1-like sites that interacted irreversibly with SCH 23390 in a stereospecific way. These sites corresponded to 25% of the total number of D1-like sites present in the retina at this developmental stage. In retina cells obtained from one-day old posthatched chicks these sites were no longer detected. These data show that cultured retina cells as well as cells obtained from retina developing in ovo display two populations of D1-like receptors. One interacts irreversibly with SCH 23390 and is present only in the undifferentiated tissue or in cells at the early stages of culture and the other has a lower affinity for SCH 23390 with which its interaction follows reversible kinetics. These sites are present throughout the differentiation stages studied.

Animals↗

PubMed1982

Catatonic behavior induced by haloperidol, increased by retesting and elicited without drug in rats.

The catatonogenic action of haloperidol in rats was assessed through different experimental procedures. In the first experiment the animals were injected intraperitoneally with haloperidol, 0.4-4.0 mg/kg, and then divided into two subgroups. The first group was tested for catatonic behavior from 20 min up to 4 h after the injection, while the second was only tested throughout the last 3- to 4-hour period. In the second experiment, animals received, either 0.2 or 0.6 mg haloperidol/kg 3 times at 15-day intervals, and were tested for catatonic behavior from 20 to 240 min after the injection. 15 days after the last drug session, the same animals were injected with distilled water and then tested for catatonia. The results showed that retesting drastically influenced the amount of catatonic behavior and that, when under no drug, the rats still displayed catatonia. The data suggest a learning component of this behavior.

Animals↗

PubMed1971

[Color slides].

Explore the source record for details and available documents.

Audiovisual Aids↗

PubMedDate not supplied

[The mother figure of children with malformations. A phenomenological study].

The theme of this research refers to children suffering congenital malformation through an analysis of their mothers' reactions in dealing with such a situation. It deals with a descriptive study along the qualitative line through the phenomenological approach. In order to attain that purpose, interviews were made and data collected. The analysis was built under the view of meaning, the orientation of those mothers, i.e. the outlook of the world from their perspective, which was tracked from the meanings (units of meaning) to actual sense based on the philosophical insight of Dr. Martin Heidegger, aiming at characterizing the mother-being in her daily life.

Attitude to Health↗

PubMedDate not supplied

[A fatal case of intestinal balantidiasis].

A fatal case of a 63-year-old pig-raising country woman with an eight-day course of nausea, vomiting, dysentery with intestinal bleeding the latter being the direct cause of death. The autopsy showed ulcerative colitis due to B. coli, which was easily observed on histological examination of the large bowel.

Agricultural Workers' Diseases↗

PubMedDate not supplied

[A quantitative analysis of the mastocytes and eosinophilic granulocytes in the myocardium of Wistar rats chronically infected by Trypanosoma cruzi. A contribution to the knowledge of myocardial fibrosis].

We did mast cell and eosinophil granulocyte counts in the myocardium of forty chronic chagasic Wistar albino rats. We used 10 controls rats and 30 animals with late-stage (8th month) infection of São Felipe, Y and Colombian Trypanosoma cruzi strains, with variable degree of chronic myocarditis. We found chronic fibrosing myocarditis (fibrosis) in 40% of the infected animals. It was detected increased mast cell count in the chagasic rats associated with infection and not related with myocardial fibrosis. There was no increase in the eosinophil counts.

Animals↗

PubMedDate not supplied

[Total mercury in hair samples of inhabitants of Tapajós River, Pará State, Brazil].

This study evaluates human exposure to methylmercury in fishermen and their families in four villages on the Tapajós river: Rainha, Barreiras, São Luís do Tapajós and Paraná-Mirim. Hair analyses were performed with atomic absorption spectophotometry. Total hair mercury levels varied between 2.9mg/g and 71.5mg/g. Paraná-Mirim showed the lowest level. The highest level was found in São Luís do Tapajós and Barreiras. The hair mercury was six to seven times higher than the established safe limit of 10mg/g. No statistically significant difference was found between the mean level of total mercury taken from the inhabitants living downstream and upstream in Itaituba village (p > 0.05). These results confirm that human exposure to methylmercury is occurring on the Tapajós river and suggest that continued fish ingestion in that region is a potential risk factor for the appearance of symptoms and signs of Minamata disease. An immediate epidemiological survey program is recommended.

Animals↗