Edson Aparecido Liberti

A Preliminary Investigation of the Effects of Aging on the Nerve Cell Number in the Myenteric Ganglia of the Human Colon

We have examined the number of nerve cells present in the myenteric plexus of the human large intestine using a nonhistochemical method (Giemsa) in laminar preparations of the muscularis externa in two groups of subjects aged 20-35 and over 65 years. The collagen and elastic system related fibers in the myenteric ganglia were also qualitatively evaluated. The total number of neurons decreased in the old subjects by over 37%. The perikaryal area of most of the neurons in both the young and old subjects fell from 101 to 200 microns2. A ganglionic capsule was present and was thicker in the ganglia from the old subjects as were the septa within the ganglia. Both collagen and elastic system fibers were more numerous in the ganglia from the old subjects. We conclude that the decrease in neuron density with age is accompanied by an apparent increase in the fibrous components of the myenteric ganglia.

Age-Induced Nerve Cell Loss in the Myenteric Plexus of the Small Intestine in Man

We examined the number of nerve cells of the myenteric plexus and the thickness of the smooth muscle in the small intestine in autopsy material of 6 young and 6 old persons. Neurons in the myenteric plexus have been visualised by a nonhistochemical method (Giemsa) in laminar preparations of the muscularis externa. Significant reductions of at least 34% in the number of neurons in the ganglia of the myenteric plexus of the old subjects were recorded in all regions of the small intestine, especially in the duodenum where the number of neurons decreased by over 38%. However, there was no significant correlation between nerve cell count and thickness of intestinal smooth muscle since no difference was found in thickness of intestinal smooth muscle between young and old subjects. The decrease in the neuron density with age could affect the potential of the enteric nervous system to influence control over several small intestinal functional parameters.

Effects of pre- and postnatal protein energy deprivation on the myenteric plexus of the small intestine: a morphometric study in weanling rats

Abstract Whole-mount preparations of small intestines from nourished (GI) and undernourished (GII) weanling rats were stained using histochemical methods. The collagen and elastic fibers in the myenteric ganglia were evaluated in histological sections. The myenteric ganglia were regular and uniform in the GI animals with many of neurons exhibiting a dark cytoplasm. In the GII animals they were irregularly arranged and most of the neurons showed a less intensely stained cytoplasm. In the GI animals, most ganglionic neurons stained intensely for acetylcholinesterase (AChE). In the GII animals most of them were unstained or moderately stained for this enzyme. A ganglionic capsule of connective tissue was present in both groups. Thin septa within the ganglia were observed only in GI animals. The number of neurons was higher for the GII animals. The ranges of perikaryon area varied from 101 to 450 μm 2 in the GI and from 51 to 200 μm 2 in the GII animals. These observations indicate that the protein deprivation alters the histological features and AChE content of myenteric ganglia of the small intestine.

Ultrastructural study of the filum terminale and its elastic fibers.

OBJECTIVE:The filum terminale (FT) is a fibrovascular band involved in the pathophysiology of tethered cord syndrome (TCS). Its morphological and ultrastructural properties remain largely unknown even though they are thought to play a role in the generation of TCS in adult patients with normal level conus medullaris. MATERIALS AND METHODS:Twenty fresh adult human cadavers had their fila measured and removed. Transversal and longitudinal sections of the proximal, middle, and distal thirds of FT were submitted to light microscopy analysis with four different techniques. Five fila were selected for longitudinal and transversal scanning electron microscopy analysis. RESULTS:The bulk of the FT is composed of 5- to 20-&mgr;m thick longitudinal bundles of Type 1 collagen separated by 3- to 10-&mgr;m intervals, although capillaries and other elements may be present. A delicate (0.05–1.5 &mgr;m) meshwork of predominantly Type 3 collagen transversal fibers connects these bundles. Abundant longitudinally oriented elastic and elaunin fibers are found inside collagen bundles. A complex tridimensional structure is evidenced on electron microscopy. CONCLUSION:The longitudinal arrangement of collagen bundles and the impressive amount of elastic and elaunin fibers should elicit considerable elastic properties to the FT. An altered elasticity mechanism has been proposed for TCS; further studies are needed with TCS patients to define whether the collagen structure, Type 1/Type 3 proportion, or elastic fiber content are altered, which could lead to new histopathological definitions of TCS, helping neurosurgeons in the difficult management of TCS patients with normal level conus medullaris.

Effects of pre- and postnatal protein deprivation and postnatal refeeding on myenteric neurons of the rat small intestine: A quantitative morphological study

We investigated weight gain, the size of the small intestine and numbers and sizes of enteric neurons in rats whose mothers had been deprived of protein during pregnancy and who themselves were deprived postpartum. Postnatally, protein deprivation was for 42 days, or for 21 days with refeeding for a further 21 days. Control animals received normal nourishment. Neurons were located by nicotinamide adenine dinucleotide (NADH) diaphorase staining, by acetylcholinesterase (AChE) activity and immunoreactivity for choline acetyltransferase (ChAT). The collagen and elastic fibers in the myenteric ganglia were evaluated histologically. The myenteric ganglia were regular and uniform in the nourished and refed groups. In the undernourished group, the myenteric ganglia were irregularly arranged and the cytoplasm of most of the neurons showed less intense staining for NADH diaphorase, AChE and ChAT. AChE activity and ChAT immunoreactivity showed that most ganglionic neurons were stained in nourished and refed groups, but the neurons of undernourished rats were unstained or moderately stained. The distribution of the connective tissue of the ganglionic capsule was similar in the three groups. There was a decrease in weight of undernourished rats, which was restored in refed rats. The size of the small intestine of the undernourished group was smaller than in the normally fed group, by about 45%, but it was similar in nourished and refed rats. After 42 days of protein deprivation the numbers of neurons that were revealed by NADH diaphorase were fewer than in well nourished rats, but numbers were not different between nourished and refed rats. These observations indicate that protein deprivation alters histological features and acetylcholinesterase activity of neurons and also reduces body weight but these were restored by refeeding.

Avaliação morfológica da união entre adesivo/resina composta e dentina irradiada com laser Er:YAG e laser Nd:YAG: estudo comparativo por microscopia de varredura

Since bonding systems were introduced in the restorative procedures carried out with esthetic materials, the treatment of dentin surfaces has been widely studied in order to establish the ideal technique. The application of 37% phosphoric acid on dentin is still the best known method. However, alternative methods for treating the dentin surface have been discussed in the literature, including the utilization of some kinds of laser irradiation. The purpose of this research was to morphologically evaluate the bond between adhesive materials and the dentin treated with Er:YAG and Nd:YAG lasers, in a comparative study by means of scanning electron microscopy (SEM). Irradiation either substituted acid etching, or was associated to it. Recently extracted bovine incisors were utilized. They received class V cavity preparations and were restored with a bonding system and a light-cured composite resin. Meanwhile, some of the teeth underwent irradiation with Er:YAG laser or Nd:YAG laser before the application of the bonding agent and the composite resin. The samples were selected, prepared for SEM and submitted to morphological analysis. Data were registered in photomicrographs. Based on the microscopic observations, we concluded that only in the dentin surfaces submitted to irradiation with Er:YAG laser and to acid conditioning there was penetration of resin into the dentine. With the Nd:YAG laser treatment, there was only visual superposition of resin over the dentin surface, which suggests that there was only occlusion of the tubules, with characteristics of fusion in the superficial dentine.

Fall in the number of intracardiac neurons in aging rats

The neurons of whole cardiac atria were stained using a NADH-diaphorase technique in young adult (3 months old) (GI) and aging rats (20 months old) (GII). Light microscopy revealed differences in the appearance of the neurons in the two groups. In GI, most ganglia contained 50-100 neurons while in GII, most ganglia usually contained 20 neurons. The mean total number of neurons in the atria of GII was 245+/-31, i.e. only 23% of the mean value in GI (1086+/-203). The mean size of the ganglionic neurons (area of maximum cell profile) was 702 microm2 in GI and 1065 microm2 in GII. Histological sections of the ganglia revealed that a capsule of collagen fibers sheaths each ganglion in both groups. In GII, the density of collagen fibers increases in the capsule and in the septa within the ganglia; yellow or red, type I collagen fibers predominate in this group. No elastic fibers were present in the cardiac ganglia of either group. It is suggested that in aging rats, structural changes and reorganization of the remnant neurons accompany neuron reduction.

Basilar expansion of the human sphenoidal sinus: an integrated anatomical and computerized tomography study

Basilar expansion of the sphenoidal sinus (BESS) was studied in order to demonstrate its critical relevance in endoscopic or microscopic endonasal surgical interventions, including access to the sphenoidal sinus itself or in transsphenoidal pituitary approaches. Direct evaluation of anatomical specimens (25 dry skulls and 25 formalin-fixed hemi heads) and the use of computerized tomography (CT) (50 dry skulls and 750 patients) showed a high BESS frequency (69%). The authors considered BESS to be critical when the posterior wall of the clivus was 2-mm thick and found a high incidence of this important anatomical variation (44%). This study also evaluated the relationship between the sinonasal septa, the clivus, and the internal carotid arteries, and a considerable regularity in the location of these structures was seen. The septa were anatomically related to the internal carotid arteries in 55% and to the clivus in 33% of the cases. In conclusion, the high frequency of critical BESS here described is relevant to endoscopic or microscopic endonasal surgical interventions, including access to the sphenoidal sinus itself or in transsphenoidal pituitary approaches.

Morphological changes in distant muscle fibers following thermal injury in Wistar rats

PURPOSE Thermal injury causes catabolic processes as the body attempts to repair the damaged area. This study evaluated the effects of a scald injury on the morphology of muscle fibers belonging to a muscle distant from the lesion. METHODS Thirty Wistar rats were divided into control (C) and scalded (S) groups. Group S was scalded over 45% of the body surface, standardized by body weight. Rats in both groups were euthanized at four, seven and 14 days following the injury. The middle portions of the medial gastrocnemius muscles were sectioned, stained with hematoxylin and eosin and Picrosirius, and submitted to histological analysis. RESULTS Control group sections exhibited equidistantly distributed polygonal muscle fibers with peripheral nuclei, characteristic of normal muscle. The injured group sections did not consistently show these characteristics; many fibers in these sections exhibited a rounded contour, variable stain intensities, and greater interfiber distances. A substantially increased amount of connective tissue was also observed on the injured group sections. CONCLUSION This experimental model found a morphological change in muscle distant from the site of thermal injury covering 45% of the body surface.

Mastication effort study using photorefractive holographic interferometry technique

The purpose of this work was the force-displacement response analysis of the masticatory process in a dried human skull by Double-Exposure Photorefractive Holographic Interferometry Technique (2E-PRHI). The load concentration and dissipation of the forces from dried human skull were analysed at applied loading stands as a Simulation of Isolated Contraction (SIC) of some mastication muscles. The 2EHI and Fringe Analysis Method were used to obtain the quantitative results of this force-displacement response. These results document quantitatively the real biomechanical response from dried human skull under applied loading and it can be used for complementary study by finite element model and others analysis type.