Passive smoking affects endothelium and platelets.

Blood was obtained before and after ten healthy male nonsmokers sat for 20 minutes in open hospital corridors beside men who were already there smoking by their own initiative. Mean values before and after passive smoking were 0.87 and 0.78 for the platelet aggregate ratio, 2.8 and 3.7 per counting chamber for the endothelial cell count, 0 and 2.8 ng/mL for the plasma nicotine concentration, and 0.9% and 1.3% for the carboxyhemoglobin level. No variable changed significantly during control periods in which the subjects sat in a room where smoking was prohibited. Passive exposure to tobacco smoke affected the endothelial cell count and platelet aggregate ratio in a manner similar to that previously observed with active smoking.

Neonatal anoxia in rats: hippocampal cellular and subcellular changes related to cell death and spatial memory.

Neonatal anoxia in rodents has been used to understand brain changes and cognitive dysfunction following asphyxia. This study investigated the time-course of cellular and subcellular changes and hippocampal cell death in a non-invasive model of anoxia in neonatal rats, using Terminal deoxynucleotidyl transferase-mediated dUTP Nick End Labeling (TUNEL) to reveal DNA fragmentation, Fluoro-Jade® B (FJB) to show degenerating neurons, cleaved caspase-3 immunohistochemistry (IHC) to detect cells undergoing apoptosis, and transmission electron microscopy (TEM) to reveal fine ultrastructural changes related to cell death. Anoxia was induced by exposing postnatal day 1 (P1) pups to a flow of 100% gaseous nitrogen for 25 min in a chamber maintained at 37 °C. Control rats were similarly exposed to this chamber but with air flow instead of nitrogen. Brain changes following anoxia were evaluated at postnatal days 2, 14, 21 and 60 (P2, P14, P21 and P60). In addition, spatial reference memory following anoxia and control treatments was evaluated in the Morris water maze, starting at P60. Compared to their respective controls, P2 anoxic rats exhibited (1) higher TUNEL labeling in cornus ammonis (CA) 1 and the dentate gyrus (DG), (2) higher FJB-positive cells in the CA2-3, and (3) somato-dendritic swelling, mitochondrial injury and chromatin condensation in irregular bodies, as well as other subcellular features indicating apoptosis, necrosis, autophagy and excitotoxicity in the CA1, CA2-3 and DG, as revealed by TEM. At P14, P21 and P60, both groups showed small numbers of TUNEL-positive and FJB-positive cells. Stereological analysis at P2, P14, P21 and P60 revealed a lack of significant differences in cleaved caspase-3 IHC between anoxic and control subjects. These results suggest that the type of hippocampal cell death following neonatal anoxia is likely independent of caspase-3 activation. Neonatal anoxia induced deficits in acquisition and performance of spatial reference memory in the Morris water maze task. Compared to control subjects, anoxic animals exhibited increased latencies and path lengths to reach the platform, as well as decreased searching specifically for the platform location. In contrast, no significant differences were observed for swimming speeds and frequency within the target quadrant. Together, these behavioral results indicate that the poorer performance by anoxic subjects is related to spatial memory deficits and not to sensory or motor deficits. Therefore, this model of neonatal anoxia in rats induces hippocampal changes that result in cell losses and impaired hippocampal function, and these changes are likely related to spatial memory deficits in adulthood.

Low energy levels in thiamine-deficient encephalopathy.

Pyrithiamine-induced acute thiamine-deficient encephalopathy was produced in adult male Wistar rats. Twenty-four hours before the onset of neurological signs the brain showed no morphological abnormalities. Encephalopathic rats had symmetrical lesions of edematous necrosis localized in the thalamus, mammillary body, and pontine tegmentum. Biochemically, encephalopathic rats had brain thiamine levels less than 20% of controls. For the assay of the concentrations of adenosine triphosphate (ATP) and phosphocreatine, the brains were fixed using 5 KW microwave irradiation and were divided into four parts: cerebral cortex, diencephalon, lower brainstem, and cerebellum. In the lower brainstem of the encephalopathic rats ATP concentrations were 89.5% of normal controls. Phosphocreatine levels were lowered to 70% of controls in the diencephalon and to 75% in the lower brainstem. Total high energy phosphate levels were decreased to 89% of controls in the diencephalon and 91% in the lower brainstem before the onset of neurological signs and to 76% and 79%, respectively, after the onset. In the cerebral cortex and cerebellum high energy phosphates were not significantly reduced. Lower high energy phosphate levels and the distribution of edematous lesions were coincident in the brain. These findings suggest that a low energy state is closely related to the formation of edematous lesions in thiamine-deficient encephalopathy.

Effects of tobacco and non-tobacco cigarette smoking on endothelium and platelets.

Endothelial damage and platelet activation may mediate increased cardiovascular morbidity and mortality in tobacco cigarette smokers. Our study was designed to determine whether acute effects of tobacco smoking on endothelium and platelets could be avoided by the substitution of non-tobacco cigarettes. Twenty healthy nonsmokers smoked two tobacco cigarettes in 20 minutes and on another occasion (separated by 1 week) smoked two cigarettes made from wheat, cocoa, and citrus plants. Mean endothelial cell counts from venous blood before and after smoking tobacco cigarettes were 2.3 and 4.8 and before and after smoking non-tobacco cigarettes counts were 2.5 and 3.0. Mean platelet aggregate ratios before and after smoking tobacco cigarettes were 0.80 and 0.65 and before and after smoking non-tobacco cigarettes they were 0.81 and 0.78. Much greater effects of tobacco smoking on endothelial cell counts and platelet aggregate ratios suggest the possibility that non-tobacco cigarette smoking may be less harmful to the cardiovascular system than is tobacco cigarette smoking.

Effect of glycerol on peripheral nerve: an experimental study.

Håkanson's method of treatment of trigeminal neuralgia by injecting glycerol into the trigeminal cistern is being used in a few clinical centers with encouraging results. We undertook this experimental study utilizing a rat sciatic nerve model to elucidate the mode of action of glycerol. Fifty-six rats were divided into three groups. The topical application of pure glycerol on the sciatic nerve was used in Group I. The intraneural injection of glycerol was used in Group II. The effect of graded concentrations of glycerol was studied in Group III. Physiological saline was the control in Groups I and II. The animals were killed at the end of either 1 or 3 1/2 weeks after the application of glycerol, and the sciatic nerves were examined with light and electron microscopy. Our results show that myelin disintegration and axonolysis occur with glycerol application. Myelinated and unmyelinated fibers are affected at random, although the most striking histological changes were seen in the myelinated fibers.

Granulocytic sarcoma presenting as an epidural mass with cord compression.

Granulocytic sarcoma (GS) usually occurs during the course of, or as a presenting sign of myelogenous leukemia. Rarely it is found before peripheral blood or bone marrow evidence of leukemia is present. We describe a man who presented with low back pain and lower extremity weakness. He had spinal cord compression due to GS without evidence of leukemia. Only four such instances have been previously reported. Such aleukemic presentations of GS are frequently misdiagnosed. The chloroacetate esterase stain and electron microscopy are useful in demonstrating the myeloid origin of GS cells. GS lesions are probably best treated by localized radiation therapy and systemic chemotherapy.

Scanning electron microscopy of the lingual mucosa of the nine-banded armadillo, Dasypus novemcinctus.

The lingual mucosa of the nine-banded armadillo, Dasypus novemcinctus, was studied by scanning electron microscopy in order to analyse its morphology. The tongue of the armadillo is long and thin, and has filiform, fungiform and vallate papillae. In the anterior part of the tongue and near the vallate papillae, single or bifurcated filiform papillae are found. The vallate papillae are located on the dorsal surface of the middle third of the tongue, and have two or four slender extremities. The fungiform papillae are elliptical or rounded, and are concentrated mainly on the tip and lateral surface of the tongue, reaching as far as the middle third of the dorsal surface. Their surfaces are flat and smooth on the dorsal side, with some taste pores. Their taste buds are located near the vallum. In the material for which freeze-cracking was used, the epithelial layer showed a characteristic mucosal structure, with many epithelial papillae containing blood vessels and bundles of collagen fibers. The basal epithelial surface of the tongue mucosa showed irregular projections that are rounded or polygonal in shape, with a depression in the center. These depressions varied in diameter.

Three-dimensional angioarchitecture of tongue corrosion casts from normal young rats.

The three-dimensional architecture of the vascular network of the rat's lingual papillae has been studied employing the corrosive resin cast technique. The casts of the microvasculature of these types of papillae (the small conical filiform, true filiform, fungiform and vallate papillae) have been observed under scanning electron microscopy (SEM). The microvascular arrangements of the filiform papillae consist of well-defined simple or twisted capillary loops. The fungiform papillae have a cylindrical form with a central hole, and the capillary network gives shape to the whole papilla. Finally, the capillary bed of the oval-shaped vallate papilla with its characteristic network and small hairpin-like loops was also examined.

Angioarchitectural arrangements in corrosion cast of the nasal septum of the Mongolian gerbil.

The three-dimensional architecture of the vascular network of the nasal septum of the gerbil rat was studied using the corrosive resin cast technique. The angioarchitecture of the nasal septum observed with scanning electron microscopy (SEM) showed that a vascular network is disposed in the lamina propria. The capillaries, arterioles, venules and arteries were closely observed in different areas of the nasal septum mucosa.

Light and scanning electron microscopic studies of the angioarchitecture of intrinsic muscle fibers of the anterior rat tongue.

Histological and scanning electron microscopy (SEM) characteristics of the microvasculature of muscle fibers in the anterior third of the adult rat tongue are described. For light microscopy, the specimens were embedded in paraffin and frontal sections were stained with Picro-Sirius. Thick sections were obtained from Spurr embedded samples and stained with toluidine blue solution. For SEM, specimens were obtained by the corrosion cast method and fractured specimens in dimethyl sulfoxide were observed with high-resolution SEM (HRSEM). The blood vessels, enveloped with a thin layer of connective tissue, had fibers running parallel to the muscular fibers. Capillary arterioles were noted following the endomysium, but their lateral branches often ran at right angles to the fibers. The capillary beds were clearly revealed in transverse sections where the individual capillaries appeared ring-like or elliptical in shape. The nuclei of endothelial cell cores could be seen on the vessel surfaces. Collagen fibers type I and III were noted in the connective tissue and in the fibrous layer of vessels.

Light and scanning electron microscopic study of the palatine mucosa of nine-banded armadillo (Dasypus novemcinctus).

The three-dimensional structure of the lamina propria of the hard and soft palatine mucosa of the nine-banded armadillo was observed by scanning electron microscopy. Sodium hydroxide cell maceration method was applied to demonstrate the architecture of the connective tissue papillae. The palatine mucosa of the armadillo had a triangular shape and measured appr. 6.5 cm length. The hard palate showed 9 transverse palatine plicae while the soft palate was smooth. In the 10% NaOH treated specimens, the lamina propria of the hard palatine mucosa showed numerous connective tissue papillae with a general finger-like shape. These structures were composed by a meshwork of collagen fibers arranged in several directions. On the other hand, the connective tissue papillae of the soft palate mucosa were scattered and small. Numerous openings of glandular ducts with circular or elliptical shape were located in the interplicae area and in the soft palate.

Nd:YAG laser effects on the occlusal surface of premolars.

PURPOSE: To evaluate with the scanning electron microscope (SEM) the effects of a pulsed Nd: YAG laser on the occlusal surface of human premolars in vitro. MATERIALS AND METHODS: Twenty normal premolars extracted for orthodontic reasons were used and separated in two groups. Group 1 received the irradiation at 2.0 watts, repetition rate of 20 Hz and 124.3 J/cm2 of energy density during 3 minutes, on the occlusal fissure. Group 2 received the laser irradiation in only half of the fissure. RESULTS: The SEM analysis revealed that in the case of shallow fissures the sealing was total but in narrow and deep fissure the sealing was partial or was in complete.

Natal teeth in cleft lip and palate patients: a scanning electron microscopy study.

Natal and neonatal teeth may occur in patients up to 30-days after birth. The presence of two neonatal teeth in cleft lip and palate patients is reported in this study describing the structural aspects of the enamel and the dentin, using scanning electron microscopy.

Scanning electron microscopy of angioarchitecture of palatine gingiva in young rabbits.

The angioarchitecture of young rabbits' palatine gingiva was studied by using the corrosion resin cast method. The vascular corrosion casts were obtained using low viscosity resin (Mercox CL-2B) and were observed with scanning electron microscopy (SEM). The palatine gingiva had areas with various arrangements. The capillaries of the palatine gingiva and interdental papillae had numerous projections, but in the gingival sulcus, the blood vessels were arranged in a flattened network from their capillary extremities. The blood vessels supplying the alveolar bone were also clearly seen.

Diameter of axons in the lingual nerve of the mouse. A preliminary investigation.

The lingual nerves from ten mice were examined so that normal axonal populations could be determined. After perfusion fixation, they were removed and processed, and sections were taken from nerves for transmission electron microscopy. The fiber-diameter spectrum of unmyelinated fibers for the mouse lingual nerve is characterized by a unimodal curve with the more pronounced peak in the medium-diameter fiber range (0.28 micron). The spectrum from the myelinated fibers also shows a population of axons of the lingual nerve (0.22-3.2 microns) that reflects different functional specializations. These data establish some baseline values for morphological evaluation of the effects of experimental lingual nerve damage.

Presence of amastigotes in the Weber's lingual salivary gland of Trypanosoma cruzi-infected mice.

The authors studied histopathologically the presence of amastigotes in the Weber's lingual salivary gland of mice infected with RC strain of Trypanosoma cruzi. Amastigotes were found in Weber's gland acini cells, excretory duct cells, intralobular connective tissue, muscle fibers and inside the acini lumen.

The arrangement of the trabecular bone in the vestibular surface of the human fetus mandible. A scanning electron microscopy study.

The characteristics of trabecular bone in human fetuses at seven to nine months of intra-uterine life were studied in the vestibular surface of the mental and body portions of the mandible. In the mental portion, many circular trabeculae joined by "bridges" were observed in the alveolar region (AR). In the 8-month old fetus are trabeculae with tortuous disposition in the medium region (MR). Oblique trabeculae with superior and inferior dispositions defining a triangular area (future mental fossae) are verified in 9-month old fetuses. Trabeculae circularly disposed and vascular foramina are present close to the apex of this area. In the basilar region (BR) some trabeculae obliquely oriented are observed disposed near to the mandibular symphysis. The longitudinal bundles of collagen fibers assume an antero-posterior direction. At 9-month age the vascular foramina range from 6 to 20 microns and the osteocyte lacunae ranging from 1 to 4 microns diameter, are present in mandibles from all ages examined. In the body portion the presence of circular trabeculae joined by "bridges" is the main characteristic of the AR. In the MR most of the trabeculae are circular and the longitudinal trabeculae of this region assume an antero-posterior direction. The laminar, antero-posterior and juxtaposed trabeculae lying parallel to mandible base are a characteristic of the BR. The bundles of collagen fibers exhibit the same pattern of the trabeculae. The vascular foramina of the BR are smaller than that of the precedent regions. In the body portion of the mandible from all ages examined the osteocyte lacunae range from 1 to 4 microns in diameter.