Subarachnoid haemorrhage and communicating hydrocephalus scanning electron microscopic observations

Summary Scanning electron microscopic changes in the subarachnoid space after subarachnoid haemorrhage are described. The obstructive changes were classified into five grades ranging from patency to total obstruction. We report a correlation between communicating hydrocephalus and obstruction above grade 3 in the parasagittal region (p < 0.01) and the lateral cerebral fissure (p < 0.05).     

Vascular proliferation and blood supply during distraction osteogenesis: a scanning electron microscopic observation.

This scanning electron microscopic study examined the spatial and temporal features of proliferating vessels of regenerating bone tissue and blood supply during distraction osteogenesis. A rat model of tibial lengthening was used with a protocol divided into a latency period of 7 days, a distraction period that lasted 14 days with a daily distraction rate of 0.5 mm in two steps, and a consolidation period of 21 days. Vascular casting was done on the hindlimbs before osteotomy and on postoperative days 7, 14, 21, 28, and 42. Scanning electron microscopic findings were correlated with radiological and histological observations. On days 7 and 14, the proliferation of periosteal vessels was pronounced and there was distinct subperiosteal bone formation on the osteotomized surfaces. On day 21, vascular branches from the medullary canal of the host bone formed a vascular network, which gave rise to multiple axial, straight vascular branches, running parallel to the direction of distraction, toward the interzone, in accordance with the progress of mineralization. On day 28, the periosteum provided vascularization to the peripheral side of the interzone whereas the center of the interzone was still relatively avascular. On day 42, the periosteal and medullary vascular channels were completely connected at the distraction site including the interzone, which was occupied by developing and mature bone trabeculae. These results suggest that vascular proliferation occurs actively during the latency and distraction periods and then gradually decreases over time. A close temporal and spatial relationship exists between formation of regenerated bone and vascular proliferation of the periosteum and medullary canal.     

Methylmethacrylate implants: a scanning electron microscopic study

Two methylmethacrylate orbital implants used for 34 and 5 years, respectively, were examined with a scanning electron microscope. One of the implants was a combination of a prosthesis and an implant containing a magnet. The magnetic force had decreased markedly, and rust crystals were apparent. The methylmethacrylate surface was irregular and rough.     

肝移植术后胆管铸型的电镜观察

目的 探讨肝移植术后胆管铸型的超微结构及其与胆道感染的关系.方法 手术过程中,无菌条件下收集11例肝移植术后患者的胆管铸型,留取标本.从留取的标本中随机抽取6例进行扫描电镜观察.结果 6例铸型表现为多种形态,在铸型中均未观察到有细菌或细菌残骸存在.结论 铸型中没有找到细菌的踪迹,胆管炎症可能不是其病因之一.     

A scanning electron microscopic investigation of in vitro osteogenesis

Summary Chick limb mesenchymal cells differentiate into muscle, cartilage, fibrous, and bone tissue. Previous reports show that when stage 24 limb mesenchymal cells are cultured in vitro, chondrocytes, myocytes, fibrocytes, and osteoblasts can be identified on the basis of morphological and biochemical parameters. The study reported here demonstrates that phenotypic expression in culture seems to be dependent on the initial plating density, Scanning electron microscopic observations indicate that when stage 24 limb mesenchymal cells are initially seeded at high densities (5 × 10⁶ cells per 35 mm culture dish), mounds of cells appear in culture. These mounds represent cartilage nodules composed of a fine fibrous matrix and chondrocytes, surrounded by a loose fibrous connective tissue matrix. Cultures initially plated at intermediate densities (2.0–2.5 × 10⁶ cells/35 mm culture dish) produce a flattened layer of fibrocytes overlying a matrix of collagen fibers and calcium phosphate deposits as determined by electron-microprobe analysis; these observations are indicative of osteoblast expression. Cells seeded at this intermediate density appear larger and possess greater surface area than cells seeded at high density. It is suggested that conditions that permit such increased cell surface area coupled with a relative compaction due to cell crowding may provide conditions permissive for osteogenesis. Based on morphological criteria, it appears that chick limb mesenchymal cell osteogenesis in vitro is not associated with chondrogenesis but represents a separate route of phenotypic expression.     

A scanning electron microscopic study of denervated neuromuscular junctions

The morphological changes of the neuromuscular junctions (NMJs) caused by nerve transection have been examined by scanning electron microscopy in the peroneus longus muscle of the Chinese hamster. The synaptic grooves in the normal NMJs are deep labyrinthine depressions partitioned by ridges and contain numerous slit-like subsynaptic folds. After denervation, the grooves become shallower with lower sarcoplasmic ridges, and the subsynaptic area of the muscle fibers gradually flattens as a whole. The subsynaptic area shows a plate-like sarcoplasmic elevation by 4 weeks and persists as a fusiform focal bulge on the atrophied muscle fiber after 4 weeks. Concurrently the subsynaptic folds decrease in number and transform into shallow pit-like invaginations. Any subsynaptic specialization has not been discernible after 16 weeks. Changes in acetylcholinesterase stainability at the NMJs have also been observed by light microscopy. No remarkable changes were noted until 4 weeks after denervation, thereafter, however, acetylcholine positive area became smaller showing more diffuse staining pattern. Atrophied muscle fibers often exhibit longitudinal splitting and the satellite cells tend to detach from the muscle surface. These evidences suggest a regenerative process which may take place during muscle degeneration.     

Sterile shunt malfunction. A scanning electron microscopic perspective

Recently, a delayed hypersensitivity reaction to silicone plastics has been demonstrated in some patients with breast and joint implants and subcutaneously injected silicone. In this study, the authors examined the internal surface of shunting systems to evaluate the cellular response to implanted silicone plastic. The distal peritoneal tubing from 20 patients with ventriculoperitoneal shunts was examined with a scanning electron microscope. Twelve tubes were removed because of documented distal shunt malfunction and eight for an elective lengthening procedure. Cultures of all tubing were negative. The catheters removed for malfunction contained a variety of cells: sometimes in clumps, sometimes associated with platelets and densely adherent to the silicone tubing wall. In several shunts, giant cells were seen with multiple foot processes adherent to the internal silicone surface. The internal surface of the tubing of two malfunctioning shunts was embedded in electron microscopy plastic and studied with transmission electron microscopy. The cells proved to be neutrophils with no evidence of silicone granules inside the cell bodies. The shunts removed for elective revision showed only a few cells, and those were never associated with platelets. There was proteinaceous material scattered on the internal surface of the tubing, but the cellular response was markedly different from that in malfunctioning shunts. The authors postulate that the findings in malfunctioning shunt tubing represent a delayed hypersensitivity to silicone similar to that seen with other types of silicone implants.     

原发性肝内胆管结石的细菌学和电镜观察研究

目的 探讨原发性肝内胆管结石与胆道感染的关系。方法 手术过程中，在无菌条件下收集35例原发性肝内胆管结石病人的胆管胆汁35份，结石30份，进行需氧菌培养，并对部分结石行扫描电镜和透射电镜观察。结果 胆汁细菌培养阳性率为94.2%，结石细菌培养阳性率为96.7%。胆汁和胆石培养出的细菌种类相似，均以肠球菌属细菌占首位，其次为大肠杆菌和克雷伯菌属。对6例肝内胆管结石行扫描电镜观察，5例行透射电镜观察，均观察到结石内的有细菌存在，这11例病人的胆汁、胆石细菌培养均呈阳性。结论 原发性肝内胆管结石内有细菌存在，可能是引起胆道感染的重要感染源之一。     

Three-dimensional architecture of the acetabular labrum--a scanning electron microscopic study

The purpose of this study was to elucidate the structural and steric microstructural characteristics of the labrum acetabula and physiologic significance on hip-joint function by electron microscope. Acetabular specimens were taken from 18 monkeys and 26 humans and divided into three layers under a microscope. We found the most superficial layer was a thin membrane of fibernet made of collagen fibrils. The second, or superficial layer, had a stratiform structure 20 micron to 100 micron in thickness. The third, or the inner layer, covered the great majority of the labrum acetabula and was made of fiber bundles running parallel to the acetabular margin. There were also fiber bundles scattered in this layer which appeared to separate the labrum acetabula. Based on the structural and steric microstructural characteristics of the labrum acetabula it is thought that the physiological functions are carried out mainly by the inner layer and that dynamically the labrum acetabula was resistant to stretching and compression in a fixed direction along the acetabular margin, but vulnerable to shearing.     

Some scanning electron microscopic observations of the ependymal surface of the ventricles of hydrocephalic Hy3 mice and a human infant

Summary Two hydrocephalic Hy 3 mice and an infant with hydrocephalus and the Arnold-Chiari malformation were examined with the scanning electron microscope. Both mice had advanced hydrocephalus but had normal appearances in the basal regions of the ventricles. However, as the ventricular walls were ascended first the cilia gradually disappeared, then the microvilli, and finally on the roof of the ventricle the ependymal cells disappeared leaving the subependymal layers exposed. The infant had mild hydrocephalus and normal ependymal appearances. The most likely explanation of these findings is that they are a consequence of raised intracranial pressure, and are not the cause of hydrocephalus.     

The tibial subchondral plate. A scanning electron microscopic study

Non-arthritic tibial plateaus were obtained from fifteen cadavera and five above-the-knee amputation specimens. After radiographs had been made, each sample was macerated and the topography of the subchondral plate was displayed by scanning electron microscopy. The surface features included small peripheral and submeniscal osteophytes, indentations, and holes penetrating the plate. The pattern of distribution of holes per square centimeter was different for the subchondral plate of the medial plateau than it was for that of the lateral plateau. More holes were present in the submeniscal area of the medial tibial plateau; the lateral tibial plateau showed a greater concentration of holes in its central area. By light microscopy, many holes were seen to be blood vessels that were lined by endothelium and contained erythrocytes.     

Biocompatibility of implant materials: A review and scanning electron microscopic study

The evolution of various plastic materials used in the manufacture of intraocular lenses is reviewed, with special reference to the problem of biocompatibility of lens haptic materials. To date, polypropylene has been found and continues to be a highly effective, relatively inert material, providing good surgical results. However, the present study and other morphologic and chemical studies have provided evidence that indicates long-term alteration of polypropylene may occur. For this reason we believe that further studies of this particular polymer are warranted. Also, a continuing search and trial of other plastics to discover an equivalent or even more efficacious haptic material seems desirable. There is a need for careful long-term follow-up of patients after intraocular lens implantation, particularly of young patients.     

Pathological and scanning electron microscopic evaluation of the 91Z intraocular lens

We analyzed 18 explanted 91Z anterior chamber lenses by light and scanning electron microscopy. Intermittent touch of the lens loops to the posterior corneal surface and the anterior chamber angle may have occurred. Erosion of the polypropylene loops into the anterior chamber angle recess and into the iris tissue was also observed. Fibrous tissue, uveal tissue, and inflammatory debris were noted on the loops, forming dense synechias at the points of contact with the angle recess. In some lenses the edges of the optics were sharp. Other significant manufacturing defects were rarely seen, and there was no evidence of degradation of polypropylene loops. The problems regarding surgical removal of this lens are discussed.     

A scanning electron microscopic study of the growth of hydroxyapatite crystals

The crystal growth of hydroxyapatite at 25° and at a constant pH of 7.4 has been studied with the aid of a scanning electron microscope. The reproducible technique of seeded growth from stable supersaturated solutions was used effectively to produce samples of the mineral at various distinct stages of growth. Phase changes were observed as the growth proceeded and these corresponded favorably in time with kinetic results reported earlier. An attempt was made to rationalize the observations in light of mechanisms proposed for the formation of hydroxyapatite under conditions foundin vivo.     

A scanning electron microscopic study on thrombogenicity of intraarterial catheters for chemotherapeutic treatment in head and neck cancer

BACKGROUND: The purpose of this study was to assess the impact of standard anticoagulation and intermittent catheter irrigation on clot formation on intraarterial chemotherapeutical catheters. METHODS: Sixteen nonheparinized catheters were placed in the carotid vessels of 10 patients. Ten catheters were perfused with chemotherapeutic drugs; six catheters were not perfused. Patients received LMWH anticoagulation; catheters were irrigated with boluses of heparinized saline daily. Catheters were retrieved for SEM evaluation after a mean intravessel placement interval of 21 days. RESULTS: All samples demonstrated accumulation of thrombotic debris on luminal sides and outsides of catheters. Obliteration was seen in three samples. Detachment of thrombus fragments was present in several specimens. No significant dependence of clot formation on placement interval and chemotherapeutic perfusion was calculated. CONCLUSIONS: Standard anticoagulation was ineffective in clot prevention. Heparinized catheters might potentially reduce the risk of clot formation. A delivery system should be engaged for continuous irrigation of catheters with heparinized saline.