Clinical and histologic evaluation of an active "implant periapical lesion": a case report

A new entity called "implant periapical lesion" has recently been described. This lesion could be the result of, for example, bone overheating, implant overloading, presence of a preexisting infection or residual root fragments and foreign bodies in the bone, contamination of the implant, or implant placement in an infected maxillary sinus. This case report describes a titanium implant that was placed in the maxillary premolar region. A fenestration involving the middle portion of the implant was present. After 7 months, the apical portion of the implant showed radiolucency. This lesion rapidly increased in size and a vestibular fistula appeared. A systemic course of antibiotics was not successful, and the implant was then removed. The histologic examination showed the presence of necrotic bone inside the antirotational hole of the implant. The etiology of the implant failure in this instance could possibly be related to bone overheating associated with an excessive tightening of the implant and compression of the bone chips inside the apical hole, producing subsequent necrosis.     

Scanning electron microscopy and energy dispersive analysis of machined denture base surfaces

We are seeing evidence of more studies investigating the effectiveness of psychosocial interventions of cancer patients, predominantly within groups. As roles within cancer and palliative care diversify, specially trained nurses and other health care workers are taking a more active role within psychosocial intervention studies. Frequently, these studies are randomised controlled trials (RCTs). Often, the results of these psychosocial RCTs have been laid open to general criticisms of design, implementation and reporting. The following paper focuses specifically on the general and experimenter problems in conducting RCTs within psychosocial interventions. It highlights the limitations and inherent problems seen with RCTs of psychosocial interventions so that health care workers are aware of these before considering undertaking psychosocial RCTs with cancer patients.     

Scanning electron microscopy of cyclosporine-induced gingival overgrowth

Overgrown human gingival specimens were examined histologically and by scanning electron microscopy (SEM) to study structural changes caused by cyclosporine. The biopsy specimens were from organ transplant recipients receiving cyclosporine to suppress the rejection of the transplanted organ. The epithelium of the overgrown gingiva was thickened, acanthotic and parakeratotic. Retepegs were anastomosing and extending into connective tissue. The SEM examination of the outer surface of the attached gingival showed loss of cellular attachments and cells were exfoliating. The normal honeycomb structure formed by interconnecting microvilli surrounding the pits was distorted. Outer gingival cell surface showed numerous round, ovoid and dome-like structures instead of parallel, reticular or fingerprint-like microridges. It was concluded that cyclosporine not only caused hyperplasia but also changed the structure of the outer epithelial cell surface.     

Scanning electron microscopy of Blastocystis hominis cysts

Scanning electron microscopy of Blastocystis hominis cysts reveals that some cysts have an outer coat, whereas others are naked. If intact, the outer coat forms a fan-like structure around the cyst and its surface is granular. The fragmented outer coat adheres to other cysts and bacteria, forming irregular clumps.     

Scanning electron microscopy and microcrystals in articular diseases

The value of scanning electron microscopy (SEM) in the study of crystals in articular diseases is underlined in several cases of examination of joint fluid, or crystal deposits in articular or periarticular tissues obtained by percutaneous or surgical treatment with chemical and crystallographic correlations. Apatite crystals. Two deposits of hydroxyapatite of the rotator cuff were studied by SEM, crystallographic techniques and chemical analysis. SEM study showed spherical aggregates of various size. Urate crystals. Three tophi were observed by SEM, with crystallographic techniques and chemical analysis. Their needle-shape and their great size (20 m) were characteristic. Calcium pyrophosphate crystals. In a case of typical clinical and radiological features, examination of joint fluid, with chemical correlation showed shorter and thicker crystals than those or urate. The precise identification of crystals is based on sophisticated crystallographic techniques such as X-ray diffraction, although SEM allows an accurate and quite simple morphologic study, most often sufficient.     

Scanning electron microscopy of melanoblastomas of the choroid

With the scanning electron microscopic study of a case of the fascicular and two cases of epithelioid melanoblastomas it has been found that the shape of the cells is more variable than it was believed before on the basis of light microscopy. Certain types of arrangement described in histological observations, e.g. the fascicular type, can also be well demonstrated by scanning electron microscopy.     

Scanning electron microscopy of normal and lased rabbit retina

This study presents the topography as seen by scanning electron microscopy of the rabbit retina in general and the photoreceptors in particular; and of large laser lesions in the retina.     

Scanning electron microscopy of the developing renal glomerulus

The constant progress in histological technology opens up new possibilities in morphogenetic research, particularly when a three-dimensional picture is desirable. In the present study a retrograde vascular fixation, methacrylate casts of blood vessels and scanning electron microscopy have been used to reconsider the earlier observations on the development and differentiation of the renal glomerulus in the kidney of the new-born rat.     

Scanning electron microscopy of the bone-bioactive implant interface

The purpose of this study was to compare the intelligibility of two types of alaryngeal speech commonly used after total laryngectomy. Four male oesophageal speakers and four male tracheo-oesophageal speakers read a series of monosyllabic words, multisyllabic words and sentences. The monosyllabic word list consisted of several minimal pairs for each of eight phonetic contrasts; multisyllabic words and sentences were not selected on specific phonetic grounds. Audio recordings of all subjects' readings were presented to eight na?ve adult listeners who completed both an item identification task and a scaling procedure. The item identification task revealed higher intelligibility fpr tracheo-oesophageal speakers than for oesophageal speakers during the monosyllabic word condition. Results from the scaling procedure indicated that listeners' subjective intelligibility ratings were also higher for the tracheo-oesophageal speakers than for the oesophageal speakers. Moreover, a high positive correlation was found between the speakers' intelligibility scores obtained from the word identification task and the scaling procedure.     

Scanning transmission electron microscopy mass analysis of fibrillin-containing microfibrils from foetal elastic tissues

We have applied scanning transmission electron microscopy to intact native fibrillin-containing microfibrils isolated from foetal bovine elastic tissues in order to derive new insights into microfibril organisation. This technique provides quantitative data on the mass per unit length and axial mass distribution of unstained, unshadowed macromolecules. Scanning transmission electron microscopy of microfibrils from aorta, skin and nuchal ligament revealed that the beads corresponded to peaks of mass and the interbead regions to troughs of mass. These major features of axial mass distribution were characteristic of all microfibrils examined. Tissue-specific and age-dependent variations in mass were identified in microfibrils that were structurally comparable by rotary shadowing electron microscopy. Increased microfibril mass correlated with increasing gestational age. The additional mass was associated predominantly at, or close to, the bead. Some microfibril populations exhibited pronounced assymetry in their axial mass distribution. These data indicate that intact native microfibrillar assemblies from developing elastic tissues are heterogeneous in composition. Loss of mass following chondroitinase ABC or AC lyase treatment confirmed the presence of chondroitin sulphate in nuchal ligament microfibrillar assemblies.     

Hypothalamic hamartoma: report of a case with unusual histologic features

A rare case of hypothalamic hamartoma with unusual radiologic and histopathological features is described, possibly the first of its type in English literature. A 1.5-year-old female child presented with precocious puberty. MR scan of the brain revealed a pedunculated hypothalamic mass, most of which was isointense with normal brain on T1- and T2-weighted images. However, a sizeable component of the lesion was hyperintense on T1-weighted images, suggestive of adipose tissue. Microscopically, the lesion was a hamartoma composed of an admixture of neuroectodermal elements, namely glial cells, neurons, and nerve bundles along with mesenchymal elements in the form of fibroadipose tissue.     

Scanning electron microscopy of normoxic and hyperoxic hyperbaric exposed lungs

Lungs from adult guinea pigs exposed to 1 ATA He-O2 with 200 mm Hg PO2 and 20 ATA He-O2 with 200, 400, and 600 mm Hg PO2 were studied with scanning electron microscopy. The appearance of normal alveoli is described. Even before pulmonary O2 toxicity became symptomatic, subtle changes occurred in the alveoli, such as an increase in macrophages and a marked increase in length of alveolar type-II cell microvilli. These changes occurred in animals exposed to 400 mm Hg PO2, heretofore considered below toxic levels. With increased toxic involvement, the number of alveolar type-II cells increased. A thick layer of material appeared in some of the alveoli, obscuring the Kohns pores and type-I and -II cell surfaces. The alveolar-capillary network with underlying erythrocytes was no longer observable. Lungs with the greatest toxic involvement possessed large numbers of macrophages encompassed by a fibrin-like matrix. The alveolar walls were broken down in many instances, and the alveoli were no longer discrete units but took on the appearance of an amorphous mass of lung tissue.     

Scanning and transmission electron microscopy of the spermiophores of Ornithodoros ticks: an attempt to explain their motility

The spermiophores of two tick species, the kangaroo tick, Ornithodoros gurneyi and the cave tick, Ornithodoros tholozani have been examined by scanning and transmission electron microscopy. The anterior end (head) of the spermiophore is a hemisphere covered with a hexagonal network of small projections. The rest of the spermiophore is covered with longitudinal ridges, seen in sections as cellular processes whose membranes are attached only at their anterior ends by specialized 'feet'. In the cytoplasm of the sperm cell body and just beneath the cellular processes are find filaments, which form a continuous layer in O. tholozani and bundles in O. gurneyi. Fibrils tend to be situated beneath the larger cellular processes. In scanning micrographs helical constrictions have been observed in the posterior parts of some spermiophores. It is proposed that certain of the movements observed by light microscopy in living cultures of spermiophores may be explained by contraction of the cytoplasmic filaments seen in the electron microscope.     

Scanning electron microscopy of penile papillae in intact and castrated rats

Oviduct segments from infundibulum, magnum, uterus, utero-vaginal junction and vagina of actively laying hens at preoviposition time were tested for their contractile reaction to prostaglandin E1 by in vitro or in vivo methods. Maximum stimulatory response was observed from the muscular strips of the proximal oviduct segment (infundibulum) and a complete relaxation was recorded from the distal part (vagina) at molar concentrations of 1.4 X 10(-7), 3.4 X 10(-7) and 7.0 X 10(-7). The uterine strips reacted with a stimulatory response at higher concentrations (1.4 X 10(-6) and 2.8 X 10(-6) moles), but lacked any significant change at lower concentrations. The uterovaginal muscular strips showed a mild but prolonged inhibitory response, while the magnum responded with a significant increase in the luminal pressure when tested in vivo. It is concluded that PGE1 exerts a stimulatory effect on the uterus to initiate transport of the egg to subsequent segments (utero-vaginal junction and vagina), which relax under PGE1 influence and allow passage of the egg by pressure differences.     

Scanning electron microscopy of intraocular lenses (author's transl)

Tolerance of intracular lenses is partly depending of the finishing quality of their different constituents. Several types of intraocular lenses have been studied with scanning electron microscopy: some imperfections of loop insertions and edge finish have been visualized.     

Scanning and electron microprobe analysis of metal-porcelain interface

In this investigation it was planned to study the effect of disinfection time on the dimensional stability, compressive strength and hardness of gypsum die materials. Measurements of specimens treated with disinfectant were compared with the corresponding measurements of control specimens. The results of this study indicated that there was no difference in the dimensional stability, compressive strength and hardness. Therefore using the disinfectants will not affect gypsum die material.     

Scanning electron microscopy of central nervous system cerebrospinal-fluid-contacting surfaces: a bibliography (1963-1995)

This bibliography is compiled to assist in locating papers related to the application of scanning electron microscopy (SEM) to cerebrospinal-fluid-contacting surfaces in vertebrates. The use of SEM by neuroscientists has continued apace since the publication of the first bibliography in 1980. SEM studies now include more than 50 species of vertebrates and range from cyclostomes to humans; they encompass development from embryo to senescence and concern both normal and pathologic morphology. Although remarkable strides have been made toward a greater understanding of many aspects of the structure and function of cerebrospinal-fluid-contacting surfaces, many significant problems await the judicious application of scanning electron microscopy.