Scanning electron microscopic characteristics of small-incision intraocular lenses

PURPOSE: To evaluate the surface characteristics of commonly used, small-incision, intraocular lenses (IOLs). METHODS: Representative samples of five groups of foldable IOLs (4 silicone and 1 acrylic) underwent surface and edge-finish examination using a slit lamp. The IOLs were folded using a folding block and forceps. All the IOLs then were examined using a scanning electron microscope. A one-piece polymethylmethacrylate IOL was used for comparing surface-finish characteristics. The IOLs were examined for optic surface quality, edge finish, haptic, haptic/optic junction, and possible post-folding modifications. RESULTS: Slit-lamp evaluation of the surface quality of all of the silicone lenses demonstrated a smooth finish of the optic surface, edge, and haptics. Scanning electron microscopic analysis of the IOLs demonstrated adequately finished haptics or footplates and optics. Excess molding flash was seen on the edges of the some of the silicone IOLs, and no molding flash was observed on others. The acrylic IOL had a somewhat sharper optic edge. Irregular finish of the haptic/optic junctions of some of the IOLs (both silicone and acrylic) was noted. CONCLUSIONS: Currently available foldable IOLs have demonstrated adequate lens finish. However, irregularities of the haptic/optic junctions and molding flash are present on most IOLs evaluated, indicating room for improvement in the finish of foldable IOLs. Phacoemulsification with capsular bag IOL placement may decrease the clinical significance of these relatively subtle lens finish irregularities.     

Scanning electron microscopic and immunohistochemical studies of pelvic endometriosis

The pathogenesis of pelvic endometriosis has been studied by using scanning electron and light microscopy, observing the surface structure of bluish lesions obtained from 26 patients during laparotomy. Paraffin sections included another 17 tissue samples of endometriosis, based on immunohistochemical responses to epithelial membrane antigen, keratin and vimentin. Ultrastructurally, the surface epithelial cells could not be detected in 13 out of 17 pelvic peritoneal endometriosis samples. In one case in which the surface peritoneal cells were seen histologically to dip into the subperitoneal stroma, many surface peritoneal infoldings were observed, and ciliated cells were detected at the edge of these infoldings. Ovarian endometriosis was composed of three types of cells, none of which had any cilia. These findings were observed in continuity with adjacent normal mesothelial cells. No characteristic structure of the endometrial surface was observed for the bluish lesion, but the gland surface of endometriosis located in the subperitoneal stroma initially had ciliated cells. The immunoreactions in both the columnar mesothelial cells with surface peritoneal infoldings and the glands of endometriotic tissues were similar to those of normal endometrial glands, but different from those of normal mesothelial cells. Pelvic endometriosis might originate by a process of metaplasia from the pelvic peritoneum.     

Scanning electron microscopic view of auditory tonsil in turkey

The auditory tonsil of the turkey was studied by scanning electron microscopy. It is a sizable mass of lymphatic tissue dorsal to the infundibular opening in the auditory tube. The infundibular opening is in the roof of the turkey's mouth, caudal to the nasal cleft, and is the external orifice of the auditory tube that connects with the air spaces of the pneumonic bones in the head. Folds of the auditory tonsil that project toward or into the infundibular opening contained numerous lymphatic nodules in their lamina propria. The epithelial surface of the folds was covered with ciliated and nonciliated columnar cells, goblet cells with microvilli, and ductal openings of mucous glands located in the area. The lymphoid nodules were either oval or round and consisted of a thick reticular network that contained lymphocytes, fibroblasts, and erythrocytes. From some of the lymphatic nodules, there were sinusoids that contained lymphocytes and extended to the epithelial surface, whereas from others there was a lymphocytic infiltration of the surrounding lamina propria.     

Scanning electron microscopic study of the development of crystalline lens fiber

Examines types of social support that best predicts adherence at different time points during a 1-year endurance exercise program in 269 women and men ages 50 to 65 years. Results indicate that social support had similar effects on exercise participation for women and men, and support specific to exercise was a better predictor of exercise adherence than general social support. A preference for receiving a lesser amount of initial support from exercise staff was the strongest social support-related predictor of exercise adherence during the initial 6 months of the program. Support currently received from family and friends and exercise staff at Month 6 was found to be the strongest predictor of adherence during Months 7 to 12. Format of exercise was also a strong predictor of exercise adherence with home-based programs related to greater adherence. Additionally, divorced nonsmokers appear to be at increased risk for poor early exercise adherence and should be targeted in interventions to promote exercise participation.     

Scanning and transmission electron microscopic studies of lesional epidermis in herpes zoster

The epidermal skin lesions of herpes zoster were studied by scanning (SEM) and transmission electron microscopy (TEM). When erythematous lesions were observed by TEM, many of the infected keratinocytes showed evidence of cell degeneration, being characterized by swollen nuclei, disappearance of desmosomes, and widening of intercellular spaces. Macrophages and/or lymphocytes migrated through the intercellular spaces between degenerated keratinocytes. In the vesicular lesions, SEM and TEM showed some infiltrating neutrophils, directly adhering to the virus-infected keratinocytes, with swollen nuclei and irregularly clumped chromatin. In some specimens, balloon-degenerated keratinocytes were observed in the cavity. In the pustular stage, ruptured keratinocytes and numerous neutrophils were observed in the reticular-degenerated epidermal tissue. These results suggest that, in herpes zoster, the epidermal damage may be due, at least in part, to cell-mediated host immunity as well as to the cytopathic effect of varicella-zoster virus.     

Microangioarchitecture of rat parietal cortex with special reference to vascular "sphincters". Scanning electron microscopic and dark field microscopic study

Microangioarchitecture of the rat parietal cortex was studied by means of scanning electron microscopy and dark field microscopy. The richest supply of blood vessels in the parietal cortex was found in layer III + IV and layer V, where 2 isolated plexuses of microvessels were prominent. The appearance of the plexuses was quite different between motor and sensory areas. In the motor area the capillary plexuses were narrow and compact, while in sensory area the plexuses were wide and diffuse. Characteristic ring formations, called ring-shaped-compressions in the present study, were frequently observed at branching sites of arterioles. The ring-shaped-compression probably corresponds to the precapillary sphincter. A similar structure was also seen in capillaries and venules and, therefore, it is likely that not only arterioles, but also capillaries and even venules, can actively change diameter to control cerebral blood flow.     

Scanning electron microscopic observations of normal and regenerating nerve roots in the cat

The surface morphology of normal and regenerated nerve roots was studied using correlated scanning and transmission electron microscopic methods. Nerve roots of the cauda equina were either cut and rejoined or crossed from a segment above to a segment below. Good regeneration was observed in both experimental procedures. The regenerated nerve root sheath had alterations in surface structure created by extensive growth of collagen. Despite this collagen formation, regenerated axons crossed the anastomotic site with relative ease. Surface features of the regenerated axons were similar in appearance to those of the normal axon. Schwann cells were easily recognized, as were the collagen fibers of the endoneurium, although the endoneurium was more prominent and occupied more of the interaxonal space. Macrophages were identified as round structures with a laminated surface or as a honeycomb structure. Internal features of the regenerating axons were more difficult to identify, but mitochondria and a fibrous network were observed. These studies have demonstrated the application of scanning electron microscopic methods to visualize surface structures and cells in regenerated nerve roots.     

Scanning electron microscopic studies on untreated and transformed mouse embryo fibroblast cell cultures

Cultures of CBA T6T6 mouse embryo cells were transformed by 20-methylcholanthrene (MC) treatment in vitro. Untreated and MC treated cells and reexplanted cells of tumours originating from MC treated cells were compared by scanning electron microscopy (SEM). The 3 cultures showed considerable differences in the situation of the cells compared to each other, as well as in the number and shape of the surface formations.     

Scanning electron microscopic evaluation of the cleanliness of a new ultrasonic root end preparation

Recently introduced ultrasonic instrumentation techniques for root end preparation have revolutionized the field of endodontic surgery. The specially designed tips offer improved access to the root end and create more conservative root and preparations while decreasing the amount of retained debris. This study compared the cleanliness of root end preparations made using ultrasonic instrumentation with that of those prepared in a traditional manner using a microhandpiece bur. We used 10 extracted maxillary human premolars and molars. After cleaning, shaping, and obturation of the root canals, a 3 mm root end resection perpendicular to the long axis of the root was performed with a carbide fissure bur. The roots were randomly divided into two groups and root end preparations were made using the two aforementioned techniques. The roots were longitudinally split and sputter-coated with gold for scanning electron microscopic study. Three independent dentists used a standardized grading system to evaluate the cleanliness of the root end preparations. The ultrasonic preparation had significantly less superficial debris and a thinner smear layer than the microhandpiece preparation (p < 0.05). There were no significant differences between the canal and isthmus portions of the root end preparations within each group in either superficial debris or smear layer. This indicates that cleaner surfaces for root end cavities are created using ultrasonic retrotips than using microhandpiece burs.     

Scanning electron microscopic evaluation of different endodontic procedures on dentin morphology of human teeth

Four manual endodontic instruments, an ultrasonic and an endosonic system were studied with a view to evaluating the morphology of the smear layer and the amount of debris and pulpal residues in the apical third of human extracted straight teeth from 55- to 75-yr-old patients. The manual instruments were K files, Ergoflex files used with the step-back technique, Canal Master with its own technique, and Flex-R with the Roane technique. The ultrasonic system was Suprasson Piezo and the endosonic was Excalibur. Human extracted teeth with straight canals were used and examined under a scanning electron microscope. All manual instrumentations showed a homogeneous compact smear layer and no pulp residues. No statistical differences were observed among the four manual techniques. Ultrasonic technique showed the complete removal of the smear layer, leaving small amounts of pulp debris at the apical third, while the Excalibur showed an almost complete elimination of the smear layer, leaving a homogeneous layer of pulpal residues along the canal.     

Scanning electron microscopic study on the distribution of epithelial cells in the Eustachian tube

Canine Eustachian tube epithelium was examined by means of the scanning electron microscope. The part of the tube at the bone-cartilage junction was found to be the most active. It is here that goblet cells and large numbers of ciliated cells were found. Cilia were dense and covered by a mucus blanket. Near the tympanic end of the Eustachian tube, goblet cells were more numerous and ciliated cells less so. Near the pharyngeal end, goblet cells were numerous, while cilia were scanty and not uniform in length. Our findings support the concept that middle ear clearance is carried out by an active mucociliary mechanism as in other parts of the upper respiratory system.     

Intravital and electron microscopic observation of Ito cells in rat hepatic microcirculation

Intralobular distribution of Ito cells (fat-storing cells) in hepatic microcirculatory units was investigated through intravital fluorescence microscopy. By using a low-level ultraviolet epi-illumination and a sensitive silicon intensified target camera, the intrahepatic autofluorescence was visualized and digitally processed. In rats fed an ordinary diet, the ultraviolet-excited autofluorescence was composed of at least two different origins that could not be spectrophotometrically distinguished, namely, multiple patchy autofluorescence activities along the sinusoids and terminal hepatic venules and diffuse parenchymal autofluorescence. Multiple patchy activities showed a rapid photobleaching phenomenon under the continuous ultraviolet excitation. These fluorescent activities were completely eliminated by depleting the intrahepatic retinoid contents using a vitamin A-deficient diet for 4 weeks. Furthermore repeated administration of vitamin A significantly enhanced the patchy fluorescent activities. Electron microscopy revealed that these vitamin A fluorescent activities are colocalized with the fat droplets in Ito cells, providing evidence that Ito cells exist not only in perisinusoidal spaces but also in the perivascular spaces of the terminal hepatic and portal venules. The current intravital technique thus provides a new method to observe Ito cells in hepatic microcirculatory units in vivo.     

Scanning electron microscopic study and shear bond strength measurement with 5% and 37% phosphoric acid

Direct bonding of orthodontic attachments has become a clinical reality with the application of the acid etch technique, using 37% phosphoric acid. The objective of this study was to detect the etch pattern with scanning electron microscopy and the shear bond strength with a Hounsefield tensometer (Nene Instruments Ltd., Northampton, England) by using 37% and 5% phosphoric acid (H3PO4). It was observed that with 5% H3PO4 there was minimal enamel loss compared with 37% H3PO4. There was no significant difference in shear bond strength, when enamel surface was etched with 5% H3PO4 and 37% H3PO4.     

Electron microscopic observation on a non-occluded baculo-like virus in shrimps

A severe disease of farm-raised shrimp, Penaeus chinensis has spread throughout Chinese coasts since 1993. Recently, a baculo-like virus has been diagnosed as the causative agent for this epidemic disease. The electron microscopic observation of the virus is described. Thin sections of hepatopancreatic and hypodermic tissue of diseased P. chinensis showed many rod-shaped, enveloped, baculo-like virions in hypertrophied nuclei of infected cells. The virion was filled with a highly electron dense core. No occlusion bodies have been found. Negative stained intact virions, purified from infected tissues by centrifugation on sucrose discontinuous gradients, demonstrated that the viral envelops had been broken, but the cylindrical nucleocapside could be observed clearly. The nucleocapsid of average 62 nm x 314 nm was composed of a helix system of capsomers, giving rise to an open stacked ring structure and repeating approximately every third ring. The number of repeating unit was 13 to 15. We propose that the virus described here could be designated as Non-Occluded Shrimp Virus (NOSV) or Penaeus chinensis Baculo-Like Virus (PcBLV).     

Pancreatic neoplasms induced in Syrian golden hamsters. I. Scanning electron microscopic observations

Pancreases from Syrian golden hamsters treated with N-nitrosobis(2-hydroxy-proply)amine for 10 to 25 weeks were examined under scanning electron microscopy (SEM). Findings indicate that the neoplasms originated from the ductal epithelium and developed progressively. Adenomas were lined by epithelium of differing cells types, ranging from a flat singly ciliated form to cuboidal-columnar types, or to mixed cell populations. The epithelial lining of the ductal carcinomas exhibited tubular and papillary cystic spaces, and cell surfaces were similar to the cuboidal and columnar epithelium of adenomas and of ductal epithelial hyperplasia. However, microvilli were dense and of varied lengths. The SEM observations correlated with patterns seen in routine histologic preparations.