Electromyographic study of the longissimus dorsi and iliocostalis lumborum muscles during knee flexion and extension on a plain and on a tilt Roman table.

The objective of this paper was to analyse the activity of the longissimus dorsi and the iliocostalis lumborum muscles--components of the erector spinae muscle--in order to determine: their action potentials during the use of a plain and a tilt Roman table; 2) to compare the action potentials of the two muscles; 3) to verify if the action potential of these two muscles remain constant during the arc of movement--knee flexion and extension--divided into angle ranges, and 4) to compare the action potentials of the muscles in movements performed in a free manner and against resistance. Twenty-three young volunteers were studied electromyographically and each muscle received a needle electrode (Mise) and a surface electrode. The results showed that the table model did not determine any difference in the action potential of the muscles and that, on average, the iliocostalis lumborum muscle developed a slightly higher action potential than the longissimus dorsi muscle during the free flexion of knees on the plain table. In more than 70% of the cases, there was no difference between the action potential of the muscles over the various angle ranges of knee flexion and extension. Relatively higher action potentials were recorded during knee flexion and extension against resistance than during the same movements performed in a free manner. This shows that the paravertebral musculature responds better to an overload (8 kg) imposed on the knee flexor group, confirming the stabilizing role of the longissimus dorsi and iliocostalis lumborum muscles during knee flexion and extension on a Roman table.

Ultrastructural aspects of and observations on the permeability of the rat mesentery to colloidal iron.

In works already published, it was made clear that many researches were interested in the absorption phenomena, permeability and structure of the visceral mesothelial tissue. Attention was concentrated on the mesentery and observations were made using the application of lanthanum nitrate and osmium-amine. The penetration of lanthanum nitrate is impeded by the basement membrane situated between the connective and mesothelial tissues. The heavy salt moves through and not between the mesothelial cells by passive diffusion. No reaction was observed in general with osmium-amine, with the exception of a few cases. In those instances, the osmium-amine reacted not only in the outer surface of the mesentery, but also penetrated with no visible reaction all the way to the connective tissue where it was detected in the elastic layer. In this paper, the colloidal iron was employed using different techniques, and depositions were detected in the surface of the mesentery, in the mesothelial cells and also in the connective tissue. A final conclusion that the permeability of different layers of tissues is of great variety and has a definite capacity for selectivity is suggested.

Morphological aspects and observations about the permeability of the rat mesentery to the osmium-amine.

In a previous work we felt that many authors were interested in observing the permeability and structure of the mesentery employing many techniques and analysing the material from different points of view. Our collaboration, at that time, was limited to the study of the permeability of the mesentery to the lanthanum nitrate and we came to a final conclusion that the penetration of the heavy salt is impeded by the presence of a basement membrane, localized between the mesothelial and connective tissue layers and that it was continuous to the basal lamina, located between neighbouring mesothelial cells; we could then observe that the lanthanum traveled through the cytoplasm and not in between mesothelial cells. In this paper we analyze the behavior of the mesentery in relation to the osmium-amine and we compare it to the observations made in our previous work. Generally speaking, we were unable to observe any reaction in any of the structures of the mesentery, except for some special cases. In those not very common cases, employing special techniques, we came to the conclusion that the osmium-amine reacts in the periphery (outer surface) of the mesentery and also penetrates, sometimes with no visible reaction, all the way to the elastic layer, where a reaction can be detected.

Morphological aspects and observations about the permeability of the rat mesentery to the lanthanium Nitrate. Some comparisons with the morphology of the human mesentery.

A review in the classic literature showed that many authors were interested about the permeability and structure of the mesentery. With the evolution of new techniques, this subject came back in different research areas. The purpose of this paper concentrates in the study of the permeability of the mesentery and of other small intestine layers of the rat to the lanthanium nitrate. Some comparisons are also made with the morphology of the human mesentery. Human and rat mesentery were used in different methods, and an ultrastructural study was performed. However, in all techniques employed in our paper, we could not observe a single area of the basement membrane that was penetrated by the lanthanium nitrate. We may conclude that the penetration of the lanthanium nitrate is impeded by the basement membrane and that this penetration is also impeded in the intercellular space of the mesothelial layer by the presence of a basal lamina, which is continuous with the basement membrane, as we can see in some of our sections.

Histological and histochemical appearance of livers and kidneys of rats after long-term treatment with different concentrations of sodium fluoride in drinking water.

After a review of the controversies in the literature, a histologic and histochemical study of the livers and kidneys of 48 albino rats was performed. The animals were placed on a diet containing 1 ppm NaF in demineralized drinking water, or 1, 10 or 100 ppm NaF in tap water during 90 or 180 days. The rats treated with fluoride did not present any abnormalities with respect to weight gain, morphology, behavior, and macroscopic appearance of the livers and kidneys compared to the control animals. Microscopic examination failed to reveal any morphologic alterations in either the cells or the mitochondria of the livers and kidneys. Histochemically, the polysaccharides, the protein reactive groups and the acid and alkaline phosphatases also failed to present any visible alterations. With respect to the lipids, the kidneys and livers of the rats treated for 90 days did not show any fat deposition, whereas those treated for 180 days showed zones of deposition of lipids in the livers and kidneys with different frequencies when compared with the control animals. The association between lipid infiltration and the presence of fluoride in the drinking water, however, was statistically significant only in the livers, hence, the hypothesis that fluorinated water accelerated this process in the treated animals cannot be excluded.

Electromyographic study of the subclavius muscle.

The electromyographic study of the subclavius muscle (SM) was performed in 31 different movements, in 12 subjects (10 male and 2 female) aged from 17 to 28 years. The action potentials were obtained with an electromyograph Teca TE 4. Our findings suggest that the SM acts mainly on the stability of the sternoclavicular joint; with more or less intensity according to the degree of the clavicular interaction with the movements of the peripheral parts of the superior limb. The SM seems to act as a substitute for the ligaments of the sternoclavicular joint.