Freeze-fracture analysis of junctional complexes in the nephron of the garter snake, Thamnophis sirtalis

Zonulae occludentes are shown by freeze-fracture to be pleomorphic along the garter snake nephron. In the neck and proximal segments the occluding junctions are moderately complex with frequent discontinuities in their junctional fibrils. Junctional depth and complexity are maximal in the distal and collecting segments and discontinuities in fibrils are absent. Comparison of these results with similar observations on other tissues indicates that the zonulae occludentes in the neck and proximal segments are "intermediate" to "leaky" and that they may be "very light" in the distal and collecting segments. The findings suggest that in the garter snake nephron transepithelial flow of fluid may occur primarily by passive diffusion through the zonulae occludentes in the neck and proximal segments and by cell-mediated osmotic flow in the distal and collecting segments. Gap junctions occur only in the proximal tubule and areprobably involved in low resistance, intercellular movement of ions.     

Courting and noncourting male red-sided garter snakes, Thamnophis sirtalis parietalis: plasma melatonin levels and the effects of pinealectomy

Previous studies found that pinealectomy of male Canadian red-sided garter snakes (Thamnophis sirtalis parietalis) in the autumn, before prolonged exposure to low temperatures (hibernation), significantly impaired the expression of courtship behavior upon emergence in the spring. Additionally, pinealectomized animals with a disrupted diel cycle of plasma melatonin did not court while those exhibiting a more typical diel pattern did. These results suggested that the pineal gland functions in the transduction of a temperature cue which stimulates courtship. To test this hypothesis, we pinealectomized males in the spring after they had undergone a normal hibernation but were still courting. Pinealectomy of courting males in the spring, in each of the 3 years of study, had no effect on courtship. This result suggests that once the cue is transduced, the pineal gland no longer has a modulatory effect on courtship behavior. Finally, we took advantage of the fact that, in the laboratory, there is always a small percentage of males that do not court upon emergence. Pinealectomy of these noncourters greatly increased the percent of males expressing courtship behavior in each of the study years. Plasma melatonin levels of unmanipulated courting and noncourting males was measured after emergence in successive years. In both years, courters had a typical pattern of melatonin secretion (low in the photophase, high in the scotophase) while persistent noncourters displayed the opposite pattern.     

Luminal epithelium of Warthin's tumours: a scanning electron microscopic study

Three cases of papillary cystadenoma lymphomatosum were examined by light and scanning electron microscope to declare the morphology of the luminal epithelial surface. It was found that ciliated cells were present in one case. This finding explains the origin of ciliated cells as a development included in the neighbouring lymph node with a tendency of metaplastic change and exfoliation.     

Temperature activation of courtship behavior in the male red-sided garter snake (Thamnophis sirtalis parietalis): Role of the anterior hypothalamus-preoptic area.

Adult male red-sided garter snakes (Thamnophis sirtalis parietalis) received radio-frequency lesions prior to 17 weeks of low-temperature hibernation. Animals found to have bilateral lesions of the anterior hypothalamus-preoptic area ({ah-poa}) failed to exhibit courtship behavior on emergence from hibernation. Those individuals in which the major portion of the destruction was centered in the anterior POA also exhibited deficits in thermoregulatory behavior. Animals that received unilateral lesions of the {ah-poa} initiated courtship behavior after controls and had an abbreviated period of courtship; these animals exhibited normal responses to thermal stimuli. Male snakes with lesions outside the {ah-poa} courted normally and demonstrated no differences in thermoregulatory behavior compared with the surgical controls. These results indicate that in male red-sided garter snakes, an intact {ah-poa} is critical for the integration of thermal stimuli that activate seasonal courtship behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Morphological variations of the human gastric mucosa after omeprazole treatment: a scanning electron microscopic study

The effects of antiepileptic drugs on cognitive function in 48 healthy volunteers were assessed using event-related potentials (ERP) and the Attention Index included in the Wechsler Memory Scale, revised edition (WMS-R). The study was conducted over 1 week, using a double-blind design. Four drugs, carbamazepine (CBZ), phenytoin (PHT), valproate (VPA) and zonisamide (ZNS) were tested. Using an auditory oddball task, ERP measurements were made under two conditions with different tone intensities: Condition 1 used 70 db SPL; and Condition 2 used 30 db SPL. Results showed that CBZ prolonged target N1 and P3 latencies in Condition 1, and reduced frequent N1 amplitude in Condition 2, which suggests that CBZ may cause a change in sensory memory and prolong stimulus evaluation time. It is suggested that under a low stimulus intensity level, the sensory function itself was affected. Phenytoin was found to prolong target N1 latency in Condition 2, which also indicates a change in the sensory memory function. However, VPA did not significantly affect ERP components, except for the shortened frequent N1 latency, which could not be explained due to the limited information. It was found that ZNS augmented P3 amplitude in Condition 2, and reduced scores on the Attention Index. It is suggested that the augmentation of P3 amplitude was caused by the reduction of processing negativity as a result of the detrimental effect of ZNS on subjects' attention. However, the apparent difference between the ERP and behavioral indices suggests that caution should be exercised in assessing the results obtained only from ERP measurements.     

Fluoride toxicity: a biochemical and scanning electron microscopic study of enamel surface of rabbit teeth

The present study has been carried out to investigate the effect of fluoride toxicity on the morphology as well as inorganic chemical constituents of rabbit teeth. Rabbits were administered sodium fluoride at a dose of 10 mg NaF/kg body weight every 24 h for 18 and 23 months. The incisor and molar teeth (whole tooth) were investigated for fluoride, calcium and phosphorus content in 18- and 23-month treated animals. The enamel surfaces of incisor teeth of 23-month treated animals were examined under scanning electron microscope. A significant increase in fluoride levels and significant decrease in calcium content was found following fluoride administration for 18 and 23 months as compared to control. Ca/P ratio was significantly increased only in 23-month treated animals. The scanning electron micrographs revealed hypoplastic, rough, uneven, pitted and cracked enamel surfaces covered with granular deposits as a result of excessive intake of fluoride. It can be concluded that long term fluoride administration leads to severe structural alterations on the enamel surface, possibly through defective mineralization.     

Afferent and efferent connections of the nucleus sphericus in the snake Thamnophis sirtalis: convergence of olfactory and vomeronasal information in the lateral cortex and the amygdala

This paper is an account of the afferent and efferent projections of the nucleus sphericus (NS), which is the major secondary vomeronasal structure in the brain of the snake Thamnophis sirtalis. There are four major efferent pathways from the NS: 1) a bilateral projection that courses, surrounding the accessory olfactory tract, and innervates several amygdaloid nuclei (nucleus of the accessory olfactory tract, dorsolateral amygdala, external amygdala, and ventral anterior amygdala), the rostral parts of the dorsal and lateral cortices, and the accessory olfactory bulb; 2) a bilateral projection that courses through the medial forebrain bundle and innervates the olfactostriatum (rostral and ventral striatum); 3) a commissural projection that courses through the anterior commissure and innervates mainly the contralateral NS; and 4) a meager bilateral projection to the lateral hypothalamus. On the other hand, important afferent projections to the NS arise solely in the accessory olfactory bulb, the nucleus of the accessory olfactory tract, and the contralateral NS. This pattern of connections has three important implications: first, the lateral cortex probably integrates olfactory and vomeronasal information. Second, because the NS projection to the hypothalamus is meager and does not reach the ventromedial hypothalamic nucleus, vomeronasal information from the NS is not relayed directly to that nucleus, as previously reported. Finally, a structure located in the rostral and ventral telencephalon, the olfactostriatum, stands as the major tertiary vomeronasal center in the snake brain. These three conclusions change to an important extent our previous picture of how vomeronasal information is processed in the brain of reptiles.     

Microvasculature of the dorsum of the rat tongue: a scanning electron microscopic study using corrosion casts

The purpose of this study was to examine the microvascular system of the dorsum of the rat tongue in relation to the subepithelial connective tissue relief. Methylmethacrylate corrosion casts of the vasculature as well as specimens in which the epithelium had been removed were prepared and examined by scanning electron microscopy (SEM). The SEM images revealed four distinct layers in the vasculature of the lamina propria. Superficially, Layer 1 comprised the irregularly shaped ends of capillary loops. Layer 2 consisted of parallel ascending and descending capillaries. These two layers were drained by the subjacent Layer 3, a fish-net-like venous plexus. More deeply, Layer 4 contained arterioles ascending from the muscular layers of the tongue. The vessels of larger papillary structures formed cylindric networks supplied by several arterioles and drained through a single venule to the venous plexus in Layer 3. At their base, the capillary loops often showed a constriction, suggestive of a sphincter. Arteriovenous anastomoses were rare. The epithelium-connective tissue interface showed short conical papillae as well as larger papillary structures which corresponded in both distribution and size to the capillary loops found in the vascular casts. The results confirm that the tongue is highly vascularized and demonstrate that the vascular supply to the papillae, taste buds, and other surface structures forms a highly organized and specific system which is adapted to the specific functions of this organ in the rat.     

Role of the anterior hypothalamus–preoptic area in the regulation of courtship behavior in the male Canadian red-sided garter snake (Thamnophis sirtalis parietalis): Lesion experiments.

Lesions of the medial preoptic area and/or the ventromedial hypothalamus resulted in an abrupt and immediate decline in courtship behavior in 28 male Canadian red-sided garter snakes. Lesions of the more anterior portions of the preoptic area resulted in a more gradual, delayed decline in courtship behavior. Ss sustaining lesions dorsal, ventral, or caudal to the anterior hypothalamus–preoptic area (AH–POA) exhibited no change in courtship behavior relative to controls. Measurements of testis size, spermatogenic stage, and circulation levels of androgens revealed no differences between any of the groups. There were marked differences in the change in hematocrit over time between the groups. Results indicate that the AH–POA is involved in the control of courtship behavior in the adult male red-sided garter snake. Moreover, it is suggested that the stimulus affecting the AH–POA to activate courtship is temperature-related. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A scanning electron microscopic study of the degenerative cartilage in patellar chondropathy

Patellar chondropathy as cartilage degeneration localized in patellar cartilage in young persons is characterized by cartilaginous changes, such as softening, swelling, and fissuring. With a view to structural characterization of early cartilaginous degeneration before erosion, the morphology of affected cartilage was studied under a scanning electron microscope. The surface network of cartilage constituting fibrils had an edematous change, presenting with fibrillation on the medial facet, whereas many fibrils of the central ridge had a collagen bundle, and fissuring of varying size was observed. It appeared that a mechanical force (shearing) acting on the site of the central ridge was associated with the formation of a collagen bundle and its destruction. On the lateral facet, fibrils were arranged perpendicular to the joint surface; the superficial layer of fibrils was worn by hyper-pressure acting on the lateral facet. On the fractured surface, the coarseness of collagen fibrils showed changes that varied with the site and stage of cartilage degeneration. Frequent changes were signs of fibril loosening (coarsening), such as reduction in fibril density (i.e., edematous change), collagen fibril aggregation, and fissuring, and longitudinal restructuring of fibrils. The patellar cartilage in the patients of this series showed a structure adapted to the mechanical force. The initial structural changes of cartilage consisted of collagen fibril aggregation and reduction in fibril density. These changes give rise to matrix rarefaction, which in turn causes cartilage degeneration to progress. These changes were concurrent in both the superficial and middle layers and were not localized as basal degeneration.     

Cell membrane maturation of Friend erythroleukemic cells and tocopherol-dependent erythropoietin effect: a scanning electron microscopic study

Typical morphological features of surface structural alterations during Friend cells differentiation are described. Scanning electron microscopy (SEM) revealed that DMSO induction switched on cell alteration of the proerythroblast-like cells, possessing microvilli projections on cell membrane with some ruffles, to an advanced stage with a blebby surface. This was followed by the formation of a pear-like polarized cell separated into two zones by a narrow cytoplasmic bridge at the equatorial plane. The polarized cells showed a smooth surface and tended to disconnect into two unequal cells. The villous leukemic erythroblast has negatively charged sialic acid residues on the glycocalyx, available for latex hydrazide probe binding, while the blebby and polarized cells lack it. Tocopherol added to culture medium of DMSO-induced erythroleukemic cells prevented the formation of blebs and the polarization phenomena, without affecting hemoglobin synthesis. The tocopherol-treated cells contain available negative charges for latex hydrazide binding similar to uninduced Friend cells. Erythropoietin potentiated a repolarization ability and morphological alteration capacity to the tocopherol-treated cells and this was accompanied by a loss of glycocalyx-negative charges. At these growth conditions erythyropoietin induced a dose-dependent proliferation effect.     

Organization of the blood and lymphatic microvasculature of the gallbladder in the guinea pig: a scanning electron microscopic study

Fasciola hepatica adult worm cysteine proteinases were active-site, affinity radio-labeled with benzyloxicarbonyl-L-tyrosine-L-alanine diazomethylketone (Z-Tyr125I-Ala-CHN2). Sera from patients with fascioliasis and from rabbits experimentally infected with F. hepatica immunoprecipitated the radiolabeled parasite cysteine proteinases in immunoelectrophoresis assays. Two purified antigens were identified as part of the complex mosaic of antigens immunoprecipitated by the sera of infected patients. These antigens (Fas1 and Fas2) have been shown to be an important part of the Fharc2 precipitin band used for serologic diagnosis in humans and cattle. They showed cysteine proteinase activity with different proteolytic specificities and partial identity in double immunodiffusion assays. The results obtained in this work show that the Fas1 and Fas2 antigens are sensitive and specific antigens for diagnosis of this serious helminthic disease in humans and other susceptible hosts.     

A combined scanning and transmission electron microscopic study and electron probe microanalysis of human pineal acervuli

The frequency of postoperative infections in oncologic head and neck surgery can be reduced by the prophylactic use of antibiotics. In order to assess such preventive treatments as to their advantages and disadvantages, a controlled clinical trial was undertaken. The prophylactic use of antibiotics was used in 107 patients, operated for tumors of the upper airway-digestive tract. According to a previous randomisation, the patients received either carbenicillin either ticarcillin. The efficiency of carbenicillin and ticarcillin proved similar. The results obtained with these antibiotics turned out to be superior to those previously obtained with combined ampicillin and cloxacillin; the number of wound infections, primary and secondary, was lessened. The most frequent complications were thrombophlebitis at the site of intravenous perfusion of the antibiotics and hypokaliemia.     

A scanning and transmission electron microscopic study of fiber arrangement in the hepatic capsule

The arrangement of fibrous elements in the rat hepatic capsule was examined under a scanning electron microscope (SEM) after alkaline or acid maceration of the serous coat, in conjunction with examination of the thin sections using a transmission electron microscope (TEM). The elastic fibers appeared as thin threads in a densely meshed network, lying just beneath the serous coat. Their surface was granular with short rods in the materials fixed with paraformaldehyde. In contrast, the collagen fibers were observed as relatively thick threads, with fascicles of collagen fibrils that were uniform in size. These fascicles extended in various directions to form rough meshes that were traversed by small fascicles and anastomosed with each other. The fibrous branches of the elastic fibers extended on or into the underlying collagen fibers to be anchored, while the collagen fibers converged on many areas of the liver surface, and were transferred into the interlobular connective tissues. The findings of the present study thus suggest that the fiber arrangement plays an effective role in the mechanical protection of the fragile liver cells and delicate serous cells from pressure and friction damage by the neighboring abdominal organs and walls of the abdominal cavity due to the elastic mobility of the subserosal elastic network in addition to the possible slippery cushion of a serous layer on the serous cells.     

A scanning and transmission electron microscopic study of experimental extrahepatic cholestasis in the rat

The rat liver after extrahepatic biliary obstruction was studied by SEM and TEM in correlation with basic histochemical techniques. Cholestasis was verified by serological methods. The biochemical data (increase in serum bilirubin values, a gradual lowering of the albumin fraction), in agreement with the ultrastructural results of a sparse RER, suggested a gradual decrease of the protein synthetic activity of the hepatocyte. SEM and TEM revealed numerous fat-storing cells, closely associated with patches of connective fibrils in the subendothelial spaces. Further ultrastructural observations demonstrated: a) a proliferation of the intrahepatic biliary tree (ductular proliferation, including newly formed ducts with sacculation and diverticuli); b) an increased number of canaliculo-ductular junctions and, c) an increase in the length of the bile canalicular network due to its tortuous course, pocketing and side branching. The occurrence of an intact cytoplasmic barrier separating the bile canalicular lumen from the Disse's space together with the results obtained by retrograde infusion of ferritin into the biliary tree suggested that the regurgitation pathway by ductular reabsorption and by transhepatocytic transport is the best documented and most acceptable, at least in the rat.     

The effects of a single course of a calculus-softening scaling and root planing gel. A scanning electron microscopic study

The effect of a calculus scaling gel was evaluated as an adjunct to instrumentation in a double blind, split-mouth, clinical study. Fifteen comparable periodontally involved teeth from 5 patients were instrumented on the mesio-buccal root surface with the aid of either the test gel, placebo gel, or no gel until smoothness was achieved. Test or placebo gel was applied subgingivally for 10 minutes. Instrumentation time, ease, number of strokes, and gingival/tooth surfaces changes were recorded. Scanning electronic microscopic (SEM) evaluation of root surface topography was evaluated. The results demonstrated effective calculus removal in all treatment groups with no differences found between them. Instrumentation time, ease, and number of strokes were similar for all treatment groups. There were no harmful effects to soft or hard tissues. The results of this study do not support the use of calculus scaling gel as an adjunct to root instrumentation.     

Lipoblastic meningioma: a light and electron microscopic study

A patient with intracranial lipoblastic meningioma in the right frontal lobe is reported. The tumor was entirely made up of vacuolated cells. The nature of this rare neoplasm has been verified by light and electron microscopic studies.