Longitudinal electromyographic study of chewing patterns in complete-denture wearers. A longitudinal electromyographic study of the anterior temporal and masseter activity during habitual chewing of apple was performed on 21 subjects provided with immediate complete dentures. At the pretreatment stage, when the patients having an anterior residual dentition were chewing, the peak mean voltages showed low values (range, 48 to 58 microV). After denture placement, there was a further decrease of the temporal activity that persisted to the 6-month stage. After the dentures were relined, a significant increase in chewing force of the temporal muscles was noted at the 1-year stage. During the second year, when no corrections of the dentures were made, the temporal activity decreased below the pretreatment level. The masseter muscle chewing activity generally showed no significant changes during the 2-year observation period. The mean durations of the chewing strokes and chewing cycles were longer than values reported in dentate samples and generally displayed no significant changes during the 2-year period.


The effect of five investing techniques on air bubble entrapment and casting nodules. Five different investing techniques were used to invest lost-wax casting patterns. The use of an investing technique that subjects the invested casting ring to air pressure (40 lb per square inch) during setting was found to produce less air bubble/cast nodule incidence than did the other four techniques investigated. Not all cast nodules can be seen by the unaided eye; magnification is needed. More cast nodules than air bubbles were seen at the interface of pattern and investment, showing that there may be many air bubbles below the investment surface that are entered by the incoming alloy during casting. The effect of a surface-tension reducing (STR) agent on the air bubble incidence between pattern and investment depends on the investing technique used, although all techniques used showed a reduction in cast nodule incidence when an STR agent was used. Sprue direction was also found to influence the incidence of casting nodules.


Effects of topical fluorides and citric acid on overglazed and autoglazed porcelain surfaces. The effect of 1.23% acidulated phosphate fluoride, 0.40% stannous fluoride gels, and 2.00% citric acid solution on 150.00 overglazed and 150 autoglazed porcelain surfaces was measured using a profilometer. Application of 1.23% acidulated phosphate fluoride for periods of 16 and 32 minutes caused etching in both groups, but the autoglazed group was significantly more effected. In both groups increase in application time did not affect the amount of etching. No etching was detected in either group after the application of 0.40% stannous fluoride for 6 and 12 hours and 2.00% citric acid for 4 and 8 hours.


Incisal-edge strength of porcelain laminate veneers restoring mandibular incisors. Porcelain laminate veneers can be used to increase incisal-edge length. The purpose of this study was to determine the fracture resistance of porcelain veneer restorations on Cymel 1077 mandibular incisors that were incisally reduced 0.0, 0.5, 1.0, and 2.0 mm. Variables studied were incisal-edge length and the angle of applied force. Sixty-one porcelain laminate veneers were made to restore incisal-edge length and bonded to the prepared teeth. Samples were fractured at force angles of 130 degrees and 137 degrees. No significant difference was found between varying incisal-edge lengths (P > .05). However, the lower applied angle required greater average force to fracture (P = .005) as tested by ANOVA.


A clinical evaluation of ceramic laminate veneers. The objective of this study was to make a clinical quality evaluation of resin-bonded ceramic veneers placed in general practice. Ceramic veneers were evaluated by four independent examiners according to the California Dental Association guidelines for evaluation of dental care. In addition, bleeding and margin index and mode of tooth preparation were recorded. None of the veneers had been replaced and only two had fractured. Almost all veneers received a satisfactory rating regarding surface, color, and margin integrity. More than half of the veneers had a satisfactory anatomical form. The bleeding index was comparable to that reported for other types of crowns. An equigingival or subgingival margin was most common.


Guidelines for developing a dental laboratory infection-control protocol. Guidelines for developing a dental laboratory infection-control protocol are discussed. A detailed outline of infection-control protocol regarding universal precautions, personal protective equipment, hepatitis B vaccination, environmental and surface cleaning and disinfection, and personnel training is presented.


The effect of the mandibular buccal denture base surface on food retention. The accumulation of food debris in the buccal vestibule surrounding a mandibular denture flange was studied. This investigation focused on the effect of the thickness, physiologic molding, and slope of the buccal flange of denture base on the patient's ability to expel test-food particles from the area. Experimental denture bases were placed in the mandibular buccal vestibule of subjects having a complete natural dentition. Only the slope of the polished surface of buccal flange was found to have a significant positive correlation with the ability to expel test food from the buccal vestibule.


The effect of venting on the strength of Dicor and Hi-Ceram ceramic crowns. Research has shown that external venting improves the marginal fit of cast crowns by decreasing hydrostatic pressure during seating. In turn, improving marginal fit has been shown to increase the strength of castable glass and other porcelain systems. This study evaluated the effect on the compressive strength of crowns with vent holes placed during and after fabrication. Forty-five artificial crowns were made from each material and divided into three equal groups: (1) crowns without vent holes, (2) crowns with a vent hole placed before casting, and (3) crowns with a vent hole placed using a rotary diamond instrument after casting. Standardized crowns were acid etched, silane treated, and filled with epoxy resin to provide a support base for testing. The crowns were then loaded to failure. One-way analysis of variance showed a significant difference among groups. Scheffe's Multiple Comparison Test was used for discrimination. The Dicor unaltered and fabricated vent group and the Hi-Ceram unaltered group had significantly higher resistance to fracture.


Chronic heart failure and quality of life: the impact of nursing. Chronic heart failure has been called the final common pathway of all heart diseases. It is a long-term illness, often associated with disability and characterized by life-threatening exacerbations, that results in multiple problems for patients and their families. This paper will provide a framework for nursing action designed to maximize the quality of life of chronic heart failure patients and their families. The approaches suggested by Strauss et al. (1984) and the principles of self-care as outlined by Levin, Katz and Holst (1979) provide the theoretical basis for the suggested nursing actions. A brief overview of the pathophysiology and current treatment of heart failure is also included.


Recognizing panic in cardiac patients.

Recognizing panic in cardiac patients. Patients presenting with apparent myocardial infarctions may in fact be suffering from panic attacks; many symptoms of the latter mimic those of the former. Cardiovascular nurses who know what to listen for in patients' descriptions can recognize indications that panic may be occurring. This article describes panic attacks, panic disorder, and the long-term consequences that often accrue when this highly treatable problem is not recognized. Particularly when no evidence of myocardial damage is found, a cardiovascular nurse's recognition of panic can lead to a referral for appropriate psychological treatment, preventing years of needless suffering and unnecessary health care costs.


Shear resistance of silver- and stainless steel-reinforced glass-ionomer cements bonded to enamel and dentin. The shear bond strength to human dentin and enamel was evaluated for four glass-ionomer cements: an experimental stainless steel-reinforced glass-ionomer cement, two commercially available silver-reinforced cements, and a conventional glass-ionomer cement. Bonded specimens were stored in distilled water for 7 days during which time they were subjected to thermocycling in water baths at 5 degrees C and 55 degrees C for a 1-minute dwell time per bath and 1500 cycles. Specimens were then shear tested. The experimental stainless steel-reinforced glass-ionomer cement had a significantly higher bond strength to enamel (P < .01) and dentin (P < .05) than did the commercially available cements.


Fracture-surface analysis of a glaze-strengthened magnesia core material. The purpose of this research was to study fracture initiation in a glaze-strengthened magnesia ceramic substance used as a core material for all-ceramic crowns. The fracture surfaces of modulus of rupture bars were studied to locate the fracture initiation point. These points were located at the center of hackles that are oriented parallel to the direction of the crack advance. The distance from the fracture initiation point to the surface of the test bars was measured. A direct relationship was found between the flexure strength and the depth of the fracture initiation point. This is consistent with the theory that residual compressive stresses at the glaze-body interface inhibit the spread of flaws and are responsible for the increases in strengths observed.


On the use of the WLF model in polymers and foods. The validity of the WLF model with fixed "universal" coefficients was tested against that of the model original form with variable coefficients using published coefficients of polymers and amorphous sugars crystallization and viscosity data. The disagreement between the two versions of the model is particularly large at temperature ranges starting about 20 to 30 degrees K above the glass transition or reference temperature, excluding the former from being a model of general applicability. Because the WLF model mathematical structure entails the existence of an almost linear region near the reference temperature, establishment of its validity as a kinetic model and meaningful determination of its constants requires data spread over an extended temperature range, especially when the experimental results have a scatter.


Changes of soluble glycoproteins in dystrophic (dy/dy) mouse muscle shown by lectin binding. Lectin binding sites in skeletal muscle from normal and dystrophic (dy/dy) C57 BL/6J mice were demonstrated by use of histochemistry and electrophoresis combined with electron microscopy. The following lectins were used: Canavalia ensiformis Con A, Triticum vulgaris (WGA), Glycine max (SBA), Griffonia simplicifolia (GS II), Arachis hypogaea (PNA), Pisum sativum (PSA) and Lens culinaris (LCA). After incubation of frozen sections with Con A, WGA, GS II, PSA and LCA a sarcoplasmic staining was observed in both normal and dystrophic muscle. The most consistent light microscopic observations in the dystrophic muscles were a decreased staining intensity of the sarcoplasm after incubation with Con A, WGA, PSA and LCA, but not with GS II, and a strong staining of the interfiber connective tissue. Supernatants, deprived of organelles and membranes, were prepared from normal and dystrophic muscle by high speed centrifugation. Lectin stained Western blots of the supernatant from dystrophic muscle showed two bands (120 and 67 K) with high affinities to avidin. Further this supernatant contained two glycoprotein bands (180 and 140 K) with affinities to Con A and a number of glycoprotein bands with apparent molecular weights below 67 K showing affinities to LCA and PSA. None of these glycoprotein bands could be detected in the supernatant from normal muscle. These changes of the muscle carbohydrate components might be involved in the expression of the dystrophic syndrome This seems to be the first report on changes of soluble glycoproteins in muscular dystrophy.


Anemia of inflammation: role of T lymphocyte activating factor. Varied conditions associated with immune activation (rheumatic, infectious and malignant) are associated with a syndrome characterized by selective erythropoietic suppression. The pathogenesis of this anemia is unknown. We have cultured intact marrows from 11 patients and found decreased erythroid colony forming activity (CFU-E: colony forming unit-erythroid; p < 0.01). We analyzed sera from 23 patients with infectious, rheumatic and malignant disorders for their ability to render normal human T lymphocytes inhibitory to autologous CFU-E and burst forming unit-erythroid in vitro. Following exposure to serum from some anemic patients, normal T cells were observed to inhibit autologous CFU-E when compared to the effect elicited by T cells incubated with heterologous normal serum. Pooled data from 19 (7 not anemic, 12 anemic) serum samples using 8 different normal T cell and marrow donors revealed a significant correlation (r = 0.65, p < 0.01) between each patient's hemoglobin level and the ability of his/her serum to render T cells suppressive to CFU-E in vitro. The suppression mediated by patient serum exposed T cells on autologous CFU-E could be ameliorated by increased concentrations of erythropoietin. The serum factor was heat stable (56 degrees C) and could not be eliminated by neutralizing antibody to either gamma-interferon or tumor necrosis factor-alpha. We conclude that some patients with anemia of inflammation may have a circulating factor(s) which renders normal T lymphocytes suppressive to autologous CFU-E in vitro. The presence of a circulating serum factor in these patients may help explain how inflammatory events distant from the marrow mediate the erythropoietic suppression characteristic of this syndrome.


Mechanism of accumulation of macrophages in galactosamine-induced liver injury: effect of lipoxygenase inhibitors on chemotaxis of spleen cells. In an attempt to clarify a mechanism of macrophage infiltration in galactosamine-induced hepatic injury, we investigated chemotactic factor(s) generated by murine hepatocytes exposed to galactosamine. Hepatocytes, isolated from murine liver by perfusion and digestion with collagenase, were incubated with galactosamine. Conditioned medium was collected 24 h later and chemotaxis of murine spleen cells was measured by stimulation of the conditioned medium using a modified Boyden chamber. Chemotactic activity was demonstrated in the conditioned medium of hepatocytes exposed to more than 3 mM galactosamine. Chemotactic activity of the conditioned medium was not reduced after freeze-thawing, and found to be dialyzable (molecular weight < 12,000). Trypsin (0.25%, 37 degrees C, 30 min) or heat (56 degrees C, 30 min) treatment reduced chemotactic activity of the conditioned medium. Furthermore, chemotaxis of spleen cells was decreased in the presence of lipoxygenase inhibitors (azelastine, ketotifen). These results suggest that accumulation of macrophages in the liver could be mediated by chemotactic factor produced by the galactosamine-treated hepatocytes, and that this mechanism may contribute to the pathogenesis of hepatic injury induced by galactosamine.


Differences in the capacity of gamma-interferons from different species to induce class I and II major histocompatibility complex antigens on neonatal rat Schwann cells in vitro. We compared the capacity of unfractionated cytokines and recombinant gamma-interferons (gamma-IFN) to induce major histocompatibility (MHC) antigens on neonatal rat Schwann cells and endoneurial fibroblasts in vitro. Rat and mouse gamma-IFN were capable of induction of both class I and class II MHC antigens on both cell types although rat gamma-IFN was more potent than that of mouse. Human gamma-IFN failed to induce MHC class I or class II on either cell type. Unfractionated cytokines from the different species also differed in their capacity to induce MHC antigens. Differences in species of origin of cytokine mixtures as well as in individual cytokines, such as gamma-IFN need to be considered in studies of MHC induction. The presence of MHC class I and class II antigens on Schwann cells could render them susceptible to cytotoxic reactions and allow for the presentation of antigen, respectively.


Dentigerous cyst in a dog.

Dentigerous cyst in a dog. An infrequently occurring tumor-like lesion arising from the cellular components of the developing dental follicle is the dentigerous cyst. These odontogenic cysts have classic clinical and radiographic findings. The cysts are locally invasive and aggressive and require prompt surgical management. This case describes the diagnosis and surgical treatment of a dentigerous cyst in the mandible of a dog.


Lingually displaced mandibular canine teeth: orthodontic treatment alternatives in the dog. Lingual displacements of mandibular canine teeth often occur following retention of deciduous canine teeth. This condition often results in trauma of occlusion to the lingual aspect of the maxillary canine tooth and the further development of a periodontal pocket or an oronasal fistula. This condition can be corrected using orthodontic appliances. The purpose of this paper is to discuss and illustrate the various alternatives available for correction of this common malocclusion in dogs.


Using epoxy for dental castings.

Using epoxy for dental castings. Important features of epoxy, when used for making dental castings, include rapid production of models without mixing and the production of a precise and nearly indestructible model. The 3M Epoxy system is used to illustrate the step-by-step production of an epoxy study model.


Modified surgical treatment of intermittent open-mouth mandibular locking in a cat. Intermittent open-mouth locking related to disorders of the temporomandibular joint are not uncommon. As a result of joint laxity, the mandible shifts to one side. The coronoid process then becomes locked lateral to the zygomatic arch. These patients present with the mouth opened and an inability to close the mouth. This article describes a case of intermittent open-mouth mandibular locking in a cat and a modified surgical treatment combining zygomatic arch and coronoid process reduction.


Craniofacial development and growth in the dog. Numerous types of veterinary orthodontic treatments are reported in papers and during meetings, however little is generally known concerning craniofacial growth in dogs. Most statements in veterinary dental publications are drawn from human-oriented studies. This makes decision making in veterinary orthodontics difficult. The purpose of this paper is to review studies of craniofacial growth performed in dogs.


Diagnostic approach to malocclusions in dogs. Malocclusions may be associated with any of the cranial shapes recognized in dogs. Orthodontic treatments for malocclusions are frequently reported. However, these reports often lack a diagnostic plan and use confusing terminologies. The purpose of this paper is to describe, using standardized terms, a diagnostic approach to the most common malocclusions found in dogs.


Classification and prognostic factors of endodontic-periodontic lesions in the dog. The classification of the possible pathologic relationships between the periodontium and endodontium in man includes three separate groups. This classification system is adapted for utilization in the dog to clarify the appropriate treatment and prognosis of dog's teeth affected with endodontic-periodontic lesions. This article describes the classification and treatment planning with illustrations of each type.


The influence of dry food on the development of feline neck lesions. The pH of the tooth surface was determined in cats with neck lesions. The presumption that commercial dry cat food with an acid coating can lead to neck lesions is investigated. In general cats with neck lesions had lower pH values of the tooth surface (7.93 +/- 0.61) than healthy cats (8.65 +/- 0.58). Feeding dry cat food with an acid surface did not contribute to the pathogenesis of neck lesions.


The Angle classification system of malocclusion: is it appropriate for use in veterinary dentistry? Classifications of malocclusions in dogs have superficially followed the Angle's system. Since teeth anatomy and occlusal relationships are not the same for dogs as for humans, the use of the Angle's system can be misinterpreted. The proposal for a system for classification of malocclusions specific to the dog is presented with a discussion of the Angle's classification of malocclusions.


Natural development of periodontal disease in the dog: a review of clinical, anatomical and histological features. Periodontal disease occurs naturally in a wide range of species from rodents to humans. Clinical studies document the development of periodontal disease. Histopathology reveals the inflammatory response to plaque accumulation. This article presents a review of the clinical and histopathological features of periodontal disease in the dog.


Root canal obturation using Thermafil endodontic obturators in dog teeth. The technique of using Thermafil endodontic obturators to fill root canals in dog teeth is discussed in detail. Stainless steel carriers coated with gutta-percha were heated and inserted in instrumented canals of dog teeth. The ease of the technique is discussed and obturation efficacy is evaluated. No perfect apical seal was achieved.


Dens in dente in a six year old doberman pinscher. Developmental abnormalities of tooth shape and form are rare. Identification of dens in dente is made by radiographic and clinical examination. Pulpitis, pulp necrosis and periapical inflammation can be associated with this abnormality. The tooth should be evaluated for endodontic therapy. A review of the literature related to dens in dente is described with the findings in a doberman pinscher.


Microleakage of a composite inlay system. This study investigated the marginal seal of resin composite inlays in dentin and enamel when either unfilled resin or a second or third generation dentin bonding agent is used. Standardized mesial and distal inlay cavities were cut in 135 human third molar teeth. The teeth were randomly divided into 9 groups and inlays fabricated in a hybrid resin composite inlay material. Each group of teeth was then treated with one of 8 dentin bonding agents or an unfilled resin and cemented with a dual curing resin cement. Each group was stored in deionized water for 1 week, thermocycled between 5 degrees C, 37 degrees C and 55 degrees C for 500 cycles, then placed in 2% methylene blue solution for 15 hours. Following this the teeth were sectioned and scored for the degree of leakage observed. Marginal microleakage was minimal at enamel margins, however there was marked leakage, even when a dentin bonding agent was used, on the dentin side. Only two dentin bonding agents proved more effective than unfilled resin and in only one case was the leakage not significantly worse than in enamel.


A laboratory study of the Amalgambond Adhesive System. The shear bond strengths (SBS) of the Amalgambond Adhesive System to several substrates were determined in vitro. Ninety extracted human permanent first and second molars were used. In 30 teeth, the occlusal surfaces were ground wet on 600-grit SiC to expose the enamel and in 60 to expose the superficial dentin. Amalgam (Tytin) restorations were placed on 15 exposed dentin surfaces and sandblasted. The Metafil-A composite was transferred in three increments and each cured for 30 seconds. The SBS of the composite to enamel were determined 1 minute (A) and 24 hours after final cure (B); to dentin 1 minute (C) and 24 hours after final cure (D); of freshly mixed amalgam to dentin (E) and to previously placed amalgam (F) after 24 hours. All of the 24 hours specimens were stored in saline at 37 degrees C or 24 hours. A shear load was applied to the base of the bonded cylinders with a knife-edged rod in an Instron machine at a crosshead speed of 0.5 mm/min. The SBS were expressed in MPa and the data analyzed by Student t-test, ANOVA and Student-Newman-Keuls test. The mean +/- SD of SBS were: A: 8.15 +/- 1.74; B: 15.69 +/- 4.50; C: 6.64 +/- 1.72; D: 17.09 +/- 4.61; E: 5.10 +/- 1.73; F: 6.54 +/- 3.78. The SBS to enamel and to dentin, respectively, after 24 hours were significantly greater than after 1 minute (P = 0.0001), the SBS of A vs C (P = 0.1783), B vs D (P = 0.2180) and E vs F (P = 0.7149) were not significantly different.


Tensile adhesion evaluation in a new universal test. A tensile testing jig was designed to test adhesion between various materials and tooth surfaces, and between materials of various consistencies, modes of setting and properties. This study examined the adhesion of both flowable and condensable, light cured and chemically cured, direct and indirect restorative materials to dentin. All materials were mixed and placed according to manufacturer's directions. The bonds were tested in tension after 24 hours. The substrate was dentin, except in group 1. Results in MPa +/- SD: 1. Photobond & Photoposterior to enamel 15.84 +/- 3.93; 2. Superbond C&B and metal inlay 6.20 +/- 3.00; 3. SuperBond C&B and amalgam 5.76 +/- 1.89; 4. All-Bond and metal inlay 4.46 +/- 1.16; 5. Mirage Bond and Newbond and amalgam 2.97 +/- 0.85; 6. Vitrebond 2.06 +/- 0.95; 7. Newbond and amalgam 1.70 +/- 0.61; 8. Ketac-Bond 0.73 +/- 0.40. The groups (2,3,4), (4,5), (5,6,7) and (6,7,8) were not significantly different at the 95% confidence level, calculated by the Student-Newman-Keuls test. The testing method was useful for all materials studied.


Accuracy of second pour casts using dual-arch impressions. This study compared the accuracy of the second pour of addition silicone impressions made using custom acrylic resin complete-arch trays and two types of dual-arch trays. Thirty impressions were made of a typodont using metal dual-arch, plastic dual-arch and acrylic resin complete-arch custom trays (10 impressions/group). Tooth #30 (first molar) and tooth #32 (third molar) in the typodont were custom metal dies made in the shape of complete crown preparations. On the metal dies were scribed reference marks permitting measurements to be made in the mesial-distal, buccal-lingual and occlusal-gingival dimensions. In addition, an inter-tooth measurement between tooth #30 and #32 was made. Following impression procedures, gypsum casts were poured. The casts were removed from the impression and, 24-hours later, second pours were completed. The distances between reference marks on each cast were measured using a measuring microscope. The measurements from each second pour cast were used to compute a group mean, with values expressed as a percent deviation from the master model. A two way analysis of variance was used to compare the groups. No statistically significant differences were found in accuracy among the three type trays except in the inter-tooth measurement where the metal dual-arch tray was more accurate than the other trays.


Microleakage in the sandwich technique.

Microleakage in the sandwich technique. This study assessed the microleakage and if it was possible to reproduce the success that is seen in the oral cavity with properly placed "sandwich" restorations. Simulated Class V erosion lesions were prepared in extracted human molar teeth and restored using a Type III glass ionomer lining cement mixed mechanically at a high powder:liquid ratio of 3:1 or greater with resin composite laminated to it leaving cement exposed at the gingival margin. To update the technique for modern materials a dual cure glass ionomer lining cement was placed in a second series with resin composite laminated to it completely covering the gingival margin. The restorations were stored in water for two weeks before temperature cycled and immersed in dye. The results showed minimal leakage relative to most other published studies and that most leakage was related to the setting shrinkage of the resin composite.


Effect of fluoride concentrations on overdenture abutments. This study evaluated the preventive effect of four concentrations of fluoride. Twenty-five extracted caries-free anterior teeth from patients aged 50-70 were prepared as overdenture abutments. The teeth were sectioned mesiodistally into two halves. The teeth were covered with a protective varnish, leaving a window on the root surface and one on the cut dentin of the occlusal. The root halves were randomly divided into 5 groups of 10 specimens and each group received a different 5-minute topical treatment prior to being placed in the demineralizing solution. The treatments were: Group 1: distilled H2O only; Group 2: 100 ppm F-, Group 3: 250 ppm F-, Group 4: 500 ppm F-; and Group 5: 1000 ppm F-. The teeth were cycled for 6 hours in a demineralizing solution and for 17 hours in a fluoride-free remineralizing solution. The cycling was maintained for 10 days. The root halves were sectioned and prepared for histologic examination. The depth of the lesions were measured from standardized photo-micrographs by means of a sonic digitizer. The conclusions were: (1) the lesions on the root surface were too small to be measurable, (2) the lesions on dentin were all of similar depth, and (3) the lesions had bands within them and the width of these bands showed a dose response to the fluoride concentration of the topical application.


Methodology for proximal wear evaluation in posterior resin composites. The purpose of this study was to utilize a methodology to measure proximal wear of posterior resin composites with respect to time. A group of 10 teeth (5 premolars and 5 molars) were restored with P-30, a posterior resin composite restorative. At placement the proximal contacts were judged to be closed visually, and with unwaxed dental floss. The patients were then recalled at intervals of 6, 12, and 36 months for indirect wear evaluations. Resin composite transfer copings were made and indexed on baseline models. A zoom stereomicroscope, at 20 microns resolution, was used to determine proximal wear. For the posterior restorative material the premolar and molar teeth wore at the same rate. The amount of wear was statistically greater for premolar teeth at 6 and 12-month evaluation periods than molar teeth. At 36 months, there was no statistical difference in wear between premolar and molar teeth.


Clinical evaluation of light-cured anterior resin composites over periods of up to 4 years. Seven hundred light-cured anterior restorations were placed in the permanent teeth of 161 patients by one researcher and evaluated over 4 years. One microfilled and two hybrid resins were assessed for their handling and for gingivitis adjacent to them, surface staining, marginal staining, and color mismatch. Restorative failures were related to the material, patient age, tooth site, and class of preparation. The different handling properties of the three resins did not affect their clinical behavior. There were only 10 unsatisfactory instances from 1626 restoration observations for the four clinical parameters assessed, and no clinically significant differences were found between the three materials, apart from the initial lighter shade mismatches of the microfilled resin. There was no obvious clinical deterioration recorded for most of the restoration observations, although all restorations deteriorated slightly over the study. There were no significant failure differences between the three resins, but significantly more failures occurred in elderly patients, restored (Class V) premolar teeth, and Class IV and V preparations. Of the 43 restoration failures, 81% were from Class V preparations, which reflected undue reliance on a dentin-bonding resin system for restoration retention in premolar cervical abrasion-erosion lesions.


Effect of resin primer solvents and surface wetness on resin composite bond strength to dentin. This study investigated the effect of various solvents on resin composite bond strength to dentin with both wet and dry dentin. A generic dentin bonding system was created with HEMA as the resin in the primer. The highest bond strengths were obtained when acetone was used as the solvent on a wet dentin surface; the lowest bond strengths were obtained with water as the solvent and the primer placed on a wet dentin surface.


Enamel shear bond strengths after vital bleaching. This study examined the shear bond strengths of enamel bond formed at specific time intervals after the termination of vital bleaching. A total of 160 extracted human anterior teeth were divided into three bleaching treatment (BTx) groups (Superoxol, Proxigel, White & Brite), two bonding agent (BA) subgroups (Scotchbond Dual Cure, Scotchbond 2) and two BA control groups. After BTx for 30 days, bonds were formed at 1, 6 and 24 hours; 3 and 7 days (time interval, TI) post-termination of BTx. A total of 32 groups of n = 5 were used. Bonds were formed in nylon tubes with selected BA and Silux Plus, and ruptured 24 hours later with Instron and cable/loop to measure enamel shear bond strength (SBS). A 3 x 2 x 5 factorial ANOVA and Tukey 95% confidence interval (TCI) detected significant differences between BTx (F = 3.54; TCI = 2.7 MPa), BA (F = 9.73; TCI = 1.8 MPa) and TI (F = 9.39; TCI = 4.1 MPa). The interaction between BTx and TI was slightly significant (F = 2.02); other interactions were not significant. Post-hoc analysis showed 80% of bonds failed at the interface or by mixed cohesive composite/interfacial failure. Scanning electron microscope observations suggested association of increased density of voids in bond area at TI with lowest mean bond strengths. SBS ranged from 42.3 to 106.8% of control.


Dimensional accuracy and bond strength of addition silicones. A cross-matching study was conducted to evaluate the effect on dimensional accuracy and tensile bond strength between the materials when intermixing brands of addition silicone impression materials in a putty-wash impression. Three brands of putty-wash systems (Reprosil, Permagum, and Express), which formed nine possible combinations, were involved in this study. The dimensional accuracy was estimated from stone casts recovered from impressions of a standardized stainless steel master model. Findings indicated no adverse effect on the bond between putty and light-bodied materials of different brands. Statistical analysis indicated significant differences. However, because the actual differences in percent deviations between the intermixed groups and their respective reference groups are very small, they are presumed to be insignificant clinically.


Enamel, cementum and dentin fluoride uptake from a fluoride releasing resin composite. The purpose of this study was to determine the fluoride release by and the enamel, cementum and dentin fluoride uptake from a visible light-cured fluoride-containing resin composite. Seven circular discs of the composite were prepared and the fluoride release in distilled water determined at daily intervals for 14 days, and then after 30, 90, 180, 365 and 550 days. The baseline fluoride concentrations in enamel and cementum were determined in three successive depths by an acid etch biopsy procedure and in dentin by an abrasion biopsy procedure. Composite slabs were prepared and ligated to the enamel, cementum and dentin surfaces and the teeth were suspended in synthetic saliva for 7 or 30 days. After removal of the composite, similar biopsy procedures were performed. The teeth were then immersed in 1 M KOH for 24 hours and similar biopsies done. The fluoride concentrations were adjusted to standardized depths of 2.0 microns for enamel, 4.0 microns for cementum and 10.0 microns for dentin, and the total and bound fluoride uptake calculated. The fluoride release from the composite dropped sharply after 1 day and after 180 days reached a plateau which remained relatively constant up to 550 days. The results of this in vitro study indicated that the mineralized dental tissues acquired fluoride at various depths.


Rationale for the chemical development of angiotensin II receptor antagonists. The renin-angiotensin system (RAS) has been demonstrated to be a key element in blood pressure regulation and fluid volume homeostasis. Since angiotensin II (AII) is the effector molecule of the RAS, the most direct approach to block this system is to antagonize AII at the level of its receptor. Therefore, at Du Pont Merck the working hypothesis has been that the identification of metabolically stable and orally effective AII-receptor antagonists would constitute a new and superior class of agents useful in treating hypertension and congestive heart failure. Our program began with a detailed pharmacologic evaluation of some simple N-benzylimidazoles, originally described by Takeda Chemical Industries in Osaka, Japan. They were found to be a series of weak but selective AII-receptor antagonists with a competitive mode of action. We embarked on a program aimed to design and synthesize more potent and orally effective nonpeptide antagonists, while attempting to preserve their selective affinity for the AII receptor. The first major breakthrough in our efforts to increase the potency of these compounds came with the development of a series of N-benzylimidazole phthalamic acid derivatives. Although effective at lowering blood pressure when administered intravenously, the phthalamic acids were devoid of oral activity. The first orally active AII antagonists came with the discovery of the biphenyl carboxylic acids. Although these compounds are absorbed after oral dosing, their bioavailability was less than desired. In the hope of improving the oral absorption of these biphenyls, we investigated a variety of acidic groups as bioisosteric replacements for the carboxylic acid. The key to the discovery of nonpeptide AII-receptor antagonists with improved oral activity and duration of action resulted from replacing the carboxylic acid group with the isosteric but more lipophilic tetrazole ring. Hence, our efforts culminated in the discovery of losartan (2-n-butyl-4-chloro-5-hydroxymethyl-1-[(2'-(1H-tetrazol-5-yl) biphenyl-4-yl)methyl]imidazole, potassium salt), a highly potent angiotensin type 1 (AT1) selective receptor antagonist with a long duration of action. Losartan is currently undergoing clinical investigation for the treatment of hypertension. The history, including the rationale for the design of the compounds, and ensuing structure-activity relationships of losartan and related analogs will be described. Many of the newer compounds exceed the potency of losartan, and the best compounds in the series rival the affinity of the endogenous ligand, AII, for its receptor.(ABSTRACT TRUNCATED AT 400 WORDS)


Angiotensin II receptors and functional correlates. Angiotensin II (ANG II) is the primary mediator of the renin-angiotensin system, which has an important functional role in cardiovascular homeostasis. The angiotensin receptor and its functional correlates have been redefined by the cloning of angiotensin receptors and the discovery and widespread study of specific nonpeptide ANG II-receptor antagonists losartan (AT1 selective) and PD123177 (AT2 selective). With these antagonists, it has been possible to extend the concept of ANG II-receptor heterogeneity to virtually every tissue and species. The losartan-sensitive sites have been shown to mediate all of the major ANG II-induced biologic effects, including vasoconstriction, aldosterone and catecholamine release, and central, ANG II-induced drinking behavior. The function of the AT2 site is not fully understood, but it may be involved in neuronal ion channel modulation and in fibroblast collagen metabolism. The presence of AT2 sites in fetal tissues and in discrete locations in the brain has encouraged continued research. Losartan, which represents the first of a new class of therapeutic agents, is currently undergoing clinical trials. A growing number of other AT1-selective ANG II-receptor antagonists are under development, including L-158,809, SKF 108566, and GR117285. Rat AT1-receptor subtypes have been cloned and sequenced (AT1A and AT1B). Human ANG II receptors have also been cloned and shown to have high affinity for losartan. A number of atypical angiotensin-binding sites have been identified from mycoplasma, amphibians, and mouse neuroblastoma, which are not sensitive to either losartan or PD123177.(ABSTRACT TRUNCATED AT 250 WORDS)


Molecular cloning of AT1 angiotensin receptors. Angiotensin II is the principal effector molecule of the renin-angiotensin system. Its effects are mediated by cell surface proteins termed AT receptors. On the basis of radioligand binding studies, these have been pharmacologically subdivided into two classes, termed AT1 receptors and AT2 binding sites (Chiu AT, et al, Biochem Biophys Res Commun 1989;165:196-203). AT1 receptors appear to mediate the major cardiovascular effects of angiotensin II, whereas no known physiological properties appear to be coupled to AT2 binding sites (Wong PC, et al, J Pharmacol Exp Ther 1990;255:584-592). To gain further insight into the function of AT1 receptors we have isolated rat cDNA's and genes encoding two distinct but highly similar isoforms of AT1 receptors, termed AT1a and AT1b receptors. Two cDNA's encoding the vascular AT1a receptor were isolated by an expression cloning strategy from a cDNA library prepared from vascular smooth muscle cells. The properties of the clones isolated by this approach are consistent with known pharmacological, biochemical signaling, and tissue distribution properties of AT1 receptors. Using this cDNA as a probe, a second isoform of rat AT1 receptor was isolated from a genomic library. This receptor, termed the AT1b receptor, is 95% identical in amino acid sequence and is pharmacologically indistinguishable from the AT1a receptor. However, the tissue-specific expression pattern of the AT1b gene differs significantly from that for the AT1a receptor.


Clinical experience with angiotensin II receptor antagonists. This series of studies was designed to assess in normal volunteers the relationships between various doses (5, 10, 20, 40, 80, and 120 mg) of the orally active angiotensin II antagonist losartan (DuP 753, MK-954) and their inhibitory effect on the pressure response to a given bolus of angiotensin I or II. It was found that the maximal inhibitory effect was reached with a dose of 80 mg. The minimal dose necessary for maximal efficacy would therefore be expected to be between 40 and 80 mg. The effect lasted for more than 24 h and was related almost exclusively to the circulating levels of the active metabolite EXP3174. It remains to be demonstrated in hypertensive patients that the same dose relationship holds for the antihypertensive effect, but preliminary data already suggest that this is the case.


Clinical experience with the angiotensin II receptor antagonist losartan. A preliminary report. The nonpeptide angiotensin II (AII)-receptor antagonist losartan is a selective blocker of the pressor effects of AII. It is now being evaluated as an anti-hypertensive drug in multicenter clinical trials in the United States and other countries. Preliminary inpatient studies have shown that after 5 days of treatment, losartan--in doses of 50, 100, and 150 mg--is significantly more effective than placebo in decreasing blood pressure, and has efficacy similar to that of the angiotensin-converting enzyme (ACE) inhibitor enalapril. Large-scale dose-ranging studies in ambulatory hypertensive patients have shown that 10- and 25-mg losartan doses have brief effects in lowering blood pressure, but when given once daily, 50 mg is the minimal dose needed to produce significant day-long decreases in blood pressure. Interestingly, higher doses do not appear to exhibit greater efficacy; however, the effects of these doses are all similar to those of enalapril (20 mg once daily). Losartan's long duration of action is documented by ratios of trough (end of 24-h dosing interval) to peak antihypertensive effects, which are consistently above 50%. Clinical experiences thus far have indicated a low incidence of adverse events. Preliminary animal and in vitro investigations have shown that losartan produces beneficial effects on cardiac function, renal function, and survival that are similar to those of ACE inhibitors. Additional studies are now under way to define more fully the cardiovascular and metabolic profiles of losartan.


Improving hypertension treatment. Where should we put our efforts: new drugs, new concepts, or new management? Despite the availability of numerous antihypertensive agents, a concerted research effort to develop new approaches to hypertension treatment is necessary. Published results of large multicenter trials emphasize the benefits of available treatments in highly selected patients. A critical look at the results shows that treatment failure is frequent and side effects are common. In the Systolic Hypertension in the Elderly Program, 28 to 35% of patients did not reach the goal blood pressure, 13% stopped treatment because of side effects, and 21% required medication other than a diuretic and a beta-blocker. Basic research may bring forth novel concepts of treatment, such as neutral endopeptidase inhibition, renin inhibition, or new techniques such as gene therapy. In the meantime, among many other lines of research, type 1 angiotensin II-receptor antagonists represent a promising new group of agents for the vast majority of hypertensive patients who are renin-dependent. A different global approach to hypertension management is also needed. Because hypertension is a heterogeneous disease, individual sequential monotherapy or the "N of 1" trial aim to select the most effective drug for each patient. To achieve the accurate assessment of drug efficacy that is a prerequisite for this approach, the number of blood pressure measurements before and during drug administration must be increased. For this purpose, self-blood pressure measurement and teletransmission of results to the physician will provide a major treatment advance.


Nonneural markers in Alzheimer disease.

Nonneural markers in Alzheimer disease. Nonneural tissues are now widely used to search for abnormalities in genes as well as for other markers of dementia of the Alzheimer type (DAT). Studies of nonneural tissues can experimentally circumvent problems inherent in the study of autopsy brain, but to be meaningful, abnormalities identified in the periphery must be correlated with abnormalities in the brain, which is the tissue of clinical interest. Among the topics in DAT research that can be readily studied in nonneural cells (including tissue cultures) are molecular genetics, amyloid precursor protein formation and metabolism, systemic manifestations of immunological and inflammatory mechanisms, proteolysis, membranes, signal transduction, and mitochondria and metabolism. Although phenomena suggesting the possibility of cytoskeletal abnormalities in nonneural DAT cells have been described, the tau molecules involved in paired helical filament formation are relatively brain-specific. Since the neuropathological diagnosis of DAT depends on recognizing a pattern of changes rather than any single abnormality, it seems unlikely that any one laboratory abnormality in peripheral tissues will correlate precisely with the clinicopathological entity of DAT. However, abnormalities found in nonneural DAT cells that correlate with the existence of similar abnormalities in the brain are likely to be informative about the disease process in the patients in whom they occur.


An examination of psychometric properties of the extended scale for dementia in three different populations. The Extended Scale for Dementia (ESD), a development of the Mattis Dementia Rating Scale, has been used in the evaluation of dementia and aging and has shown substantial clinical utility. We report on analyses of its properties and internal structure in three samples of older people: 153 normals, 101 psychiatric hospital residents, and 114 patients with Alzheimer disease. The results showed good internal consistency in the two clinical samples, with much lower reliability in the normals, for whom the test was too easy. A review of the item statistics led to the use of 17 of the 23 ESD items in item component analyses in the three samples. Use of Horn's parallel analysis criterion led to the retention of three components in the normal group and one in both the hospital and Alzheimer groups. The results are compared with other work and are in accordance with the view that cognitive structure becomes more simple with increasing dementia.


Present status of boron neutron capture therapy. The neutron capture reaction 10B(1n,4He)7Li produces two energetic particles, 4He2+ and 7Li3+ that are strongly cell toxic. Due to the short range of these nuclear fragments (5-9 microns) mainly those cells that have bound or internalized a 10B-containing substance are growth-inactivated. The most critical and difficult step in an efficient boron neutron capture therapy (BNCT) is the tumour targeting. It is today possible to synthesize a large number of boron compounds and conjugate them to tumour-seeking macromolecules, such as monoclonal antibodies or different polypeptides. The boron-containing substances presently considered for therapy are sulfhydryl boron hydride (BSH) and boron-phenylalanine, (BPA) for the treatment of gliomas and malignant melanomas respectively. Other boronated compounds considered are ligands for receptor-amplified tumour cells, antibodies for tumour cells with specific antigens and thioureas for treatment of melanotic melanomas. The required boron concentration is given by the relative dose due to neutron capture in 10B and that of the competing capture reactions in nitrogen and hydrogen. Capture in nitrogen produces protons with a range of about 10-11 microns and this gives a radiation dose to all cells in the neutron activated area. Calculations show that the local concentration of 10B near the critical radiation target, DNA, must be higher than 10 ppm (10 micrograms/g). Increased emphasis will be put on the development of combinations of treatments that fulfil the requirements for attacking the microscopic spread of the tumour.


Repeated screening for carcinoma of the prostate by digital rectal examination in a randomly selected population. Of 9,026 males aged 50-69 years, 1,494 were randomly selected and invited to participate in a programme including two screenings for carcinoma of the prostate by digital rectal examination performed in 1987 and 1990. The remaining 7,532 served as a control group. Of the selected persons, 78% accepted the invitation to the first screening round and 70% to the second one. Carcinoma of the prostate was suspected in 45 of 1,163 men examined at the first screening round and in 42 of 953 at the second round. Carcinoma was confirmed by fine-needle aspiration biopsy in 13 cases from the first and in 7 from the second round. In the study group, 17.4 carcinomas were diagnosed per 1,000 men and in the control group 8.6 per 1,000 men. The screening cost was 1,640 pounds per detected cancer and 2,343 pounds per detected and potentially cured cancer. Screening for carcinoma of the prostate by digital rectal examination can be organised with a high population acceptance, and at a reasonable cost. The impact of screening on mortality in prostatic cancer remains uncertain.


Ceruloplasmin level in women with breast disease. Preliminary results. The average ceruloplasmin levels of 29 patients with active breast cancer and 22 patients in remission were 824 +/- 61 mg/l and 630 +/- 18 mg/l respectively. The average ceruloplasmin level of 17 patients with benign breast diseases was 555 +/- 29 mg/l and of 18 healthy women in a control group 584 +/- 17 mg/l. Breast cancer patients not in remission had ceruloplasmin levels which were significantly increased when compared to the other 3 groups. The CA 15-3 levels and ceruloplasmin levels were positively correlated. We propose that ceruloplasmin may be used as a tumour marker in the follow-up of patients with breast cancer.


Chordoma-natural history, treatment and prognosis. The Florence Radiotherapy Department experience (1956-1990) and a critical review of the literature. Fifteen cases of chordoma, seen between 1956 and 1990 at the Florence Radiotherapy Department are reported. Twelve of them were treated with radiotherapy and surgery, while one was left untreated. We analyzed the course of the disease in the treated cases, with particular emphasis on the problem of symptom control. The natural history of the disease seemed to be only marginally affected by the treatment and new therapeutic options are strongly needed. While actuarial survival rates at 5 and 10 years were 58% and 35% respectively (owing to the slow growth rate of this neoplasm), 10 years' symptomatic progression-free, symptom-free, and disease-free survival rates were only 25%, 17% and 8% respectively.


Disodium pamidronate versus mithramycin in the management of tumour-associated hypercalcemia. Twenty-eight consecutive hypercalcemic patients with cancer referred to our department were included in a randomized study, comparing the second generation bisphosphonate pamidronate (APD) with our standard treatment consisting of rehydration, mithramycin (repeatedly) and supportive care. Three patients were excluded, due to rapid deterioration and death, leaving 25 evaluable patients. APD was administered as a single i.v. infusion of 30, 60 or 90 mg depending on the serum calcium, while mithramycin was given in doses of 1.25 mg and repeated if necessary within the first three days. The primary endpoint of the study was the serum calcium day 6. APD normalized serum calcium in all patients, and 12 out of 14 were still normocalcemic day 12. In contrast, mithramycin was effective only in 3 out of 11 patients, and in these patients hypercalcemia recurred rapidly. The success of APD was underscored by the fact that the patients in this group achieved a significantly better performance status after treatment. No serious side-effects were recorded in either group.


Modern imaging methods in oncology.

Modern imaging methods in oncology. Modern imaging methods are very important in the management of patients with cancer and of their disease. It is vital that clinicians treating them understand the relevance of different imaging techniques for specific applications, so that the best choice can be made to aid diagnosis and monitor response to treatment. This review briefly covers the development and principles of the diverse imaging methods available, from the discovery of x-rays by Röntgen in 1895 to the recent techniques of magnetic resonance and positron emission tomography. The authors endeavour to point out the strengths and weaknesses of each method, using clinical examples where appropriate. Finally, future developments are discussed. It is hoped that this review will aid clinicians diagnosing and treating cancer patients to choose the most suitable imaging method for their patients from among the vast array available.


Epidemiology on malignant melanoma in Europe. Mortality and incidence of malignant melanoma of the skin is increasing at a rate of between 3 and 7% per year in many European countries. All over Europe melanoma is the cancer showing the most rapid increase in incidence. Within Europe the variation in incidence and mortality rates is close to a factor of ten with the disease being more common in northern than in southern Europe. Higher rates are consistently reported on intermittently exposed body sites. Skin melanoma differ from non-melanoma skin cancer with regard to sex-, age-, and anatomic distribution. There is mounting evidence from analytical studies that the increase in melanoma incidence is a result of intermittent recreational sun exposure. Severe sunburns, in particular, is a strong risk factor, being especially harmful in childhood. Outdoor work with chronic sun exposure is not associated with increased melanoma risk and it may even be protective. The total number of pigmented naevi is an important risk factor in several studies. Freckling, fair complexion, and skin which burns rather than tans at sun exposure, are other well-established risk factors. Today no non-solar environmental risk factors have been identified. Information campaigns based on our knowledge of risk factors, warning against excessive sun exposure should significantly reduce the incidence in the future. Population-based education of risk groups may lead to earlier diagnosis and thereby reduced mortality.


Functional significance of premature ventricular complex morphology evaluated during treadmill exercise stress test in patients with coronary artery disease. To evaluate the relation between premature ventricular complexes morphology and left ventricular myocardial systolic function in patients with proved coronary artery disease. Department of Cardiology at General Hospital. From 112 patients (pts) with proved coronary artery disease, thirty-three pts with premature ventricular complexes (PVC) detected during treadmill exercise stress test were selected. Two groups of pts were considered: group I-20 pts with regular contour or with a narrow notching (< 40 ms; type I PVC) and group II-13 patients with wide notching (> 40 ms; type II PVC). In each group the following parameters were studied: ejection fraction, QRS duration, duration of exercise, number of metabolic units and the prevalence of ventricular aneurysm and mitral regurgitation. Statistical significant differences were found between group I and II concerning the mean ejection fraction (59.2% vs 48.6%; p < 0.05). The prevalence of ventricular aneurysm and mitral regurgitation was higher in patients with type II ventricular premature complexes (10% vs 30%). Particular characteristics of premature ventricular complexes detected during treadmill exercise stress test, in patients with proved coronary artery disease, suggest the presence of left ventricular myocardial systolic dysfunction.


[Pulse wave velocity as expression of arterial compliance and its importance in the evaluation of arterial hypertension]. To determine the arterial compliance through the evaluation of pulse wave velocity. Open study with direct comparison of different groups within a 12 week evaluation period. 69 patients, 49 with hypertension and 20 normals individuals. Different groups with the following treatments: Isradipine, Lisinopril, Dilevalol and no therapy. There is marked differences in the pulse wave velocity when hypertensive patients are compared with normal individuals (p < 0.001). In a 12 week therapeutic evaluation there is an improvement in the pulse wave velocity particularly when the arterial pressure was lowered to normal values in the hypertensive patients: Lisinopril (p < 0.005), Isradipine (p < 0.005), Dilevalol (p < 0.025). It is very easy to evaluate the pulse wave velocity. Arterial compliance, which may be evaluated using the pulse wave velocity, is significantly reduced in hypertensive patients, compared with age-matched control subjects. The use of antihypertensive drugs is associated with changes in arterial compliance. There is a significant decrease in the pulse wave velocity after the administration of ACE inhibitors, calcium channel blockers and beta blockers for an equivalent fall in blood pressure. These observations emphasizes the potential importance of the changes in the large arteries, considered as either an associated factor or a consequence of elevated blood pressure, in the evaluation of the cardiovascular morbidity, and mortality of patients treated for hypertension.


[Occurrence of dynamic atrial spontaneous contrast in patients with mitral disease]. The aim of this study was to analyze, through transesophageal echocardiography, different factors related to left atrial spontaneous echocardiographic formation. Transthoracic and transesophageal comparative study of left atrial thrombotic phenomena. Ambulatory and in hospital patients referred to Gregorio Marañon General Hospital Echocardiographic Laboratory. 120 consecutive patients with mitral valve disease or prosthesis were included in this transesophageal echocardiographic prospective study. All patients were divided in two groups, according with left atrial spontaneous contrast. In each patient we measured total left atrial area, rhythm abnormalities, mitral valve area, left atrial cavity thrombus and maximal mitral regurgitation area. Transthoracic echocardiography did not detect any patient with left atrial spontaneous contrast, compared to 57.5% diagnosed through the transesophageal technique. Transesophageal echocardiography diagnosed left atrial thrombosis in 19% (n = 23) of patients compared to 1% (n = 2) through the transthoracic technique. In the group with left atrial contrast, 59% of patients had mitral regurgitation less than 600 mm2, 64% were in atrial fibrillation and left atrial total area was 28 +/- 10.8 mm2. Transesophageal echocardiography is the technique of choice to diagnose, with greater security, left atrial cavity thrombosis, and establish the relationship of echocardiographic variables and left atrial thrombotic phenomena. Among these echocardiographic factors, left atrial dynamic spontaneous echocontrast is fundamental.


[Formation of left ventricular thrombus in acute myocardial infarction: significance of the determination of fibrinogen, of products of fibrinogen degradation, and of plasminogen]. To evaluate the significance of the fibrinogen, the plasminogen and the fibrinogen degradation products levels as marks of left intraventricular thrombosis (LIVT) in acute myocardial infarction (AMI). 219 consecutive patients of AMI admitted in a Coronary Care Unit of an University Hospital, were prospectively studied. All protocols included a clinical evaluation, an M-mode and 2D echocardiographic study and blood samples, at day 1, 3, 7 and at hospital discharge. In the intraventricular thrombus evaluation just the 4 Asinger grade was considered. In the laboratory evaluation we used: the Clauss chronometric method for the fibrinogen, the colorimetric method for the plasminogen and the agglutination in plaque for the FDP. The patients with ECO in the 2 or 3 Asinger grades and those in which ECO and laboratory study were not performed in the same day, were excluded. 101 patients remained on the study, and they were divided in two groups: 53 patients with LIVT and 48 patients without it. In both groups the fibrinogen raised along the first six days of the AMI, however in the group with LIVT this level didn't raise as high as in the group without LIVT (p < 0.001). In the FDP evaluation two peaks were found, one at 48 hours and another on the 6 th day, but there were no differences between the two groups. The plasminogen values raised along the first week of AMI, in a similar way in both groups. a) Fibrinogen levels raises in AMI, but this elevation is significantly smaller in the group with LIVT, which suggests fibrinogen consume in fibrin formation of the thrombus. b) FDP and plasminogen levels raise along the first week of AMI, but in a similar way in the two groups. c) None of these parameters permitted to individualize patients with thrombus formation.


[Amiodarone in heart insufficiency].

[Amiodarone in heart insufficiency]. The purpose of this study was to analyse the effects of amiodarone on the treatment of cardiac failure. The effects of 200 mg/day of amiodarone were assessed in 18 patients with a history of cardiac failure. Functional class, heart rate, blood pressure, left ventricular ejection fraction, heart size, treadmill exercise tolerance and electrocardiogram were assessed before and eight weeks after the use of amiodarone, and the side effects were monitored. In 18 patients receiving amiodarone, the functional class and heart rate decreased significantly (p < 0.05) from 2.7 +/- 0.4 to 1.2 +/- 0.4 and 103 +/- 15 to 69 +/- 8.5 beats/min respectively. The ejection fraction and the exercise tolerance increased significantly (p < 0.05) from 29.2 +/- 5.5% to 41.5% and from 379.8 +/- 271 sec to 897.8 +/- 350.8 sec respectively. The incidence of atrial and ventricular arrhythmias decreased significantly and no side effects were observed. Amiodarone appears to produce benefits in patients with cardiac failure with atrial and ventricular arrhythmias.


[Treatment of heart insufficiency in the elderly with converting enzyme inhibitors]. The main objectives of the treatment of Congestive Heart Failure are the improvement of quality of life and the reduction of mortality. Both are accomplished by the ACE inhibitors. The most important trials on the effect of ACE inhibitors on the improvement of the quality of life are reviewed. Trials about the reduction of mortality with ACE inhibitors are analysed. The sudden death problem was considered and so the relationship of this with ventricular arrhythmias. The recent evidence of a beneficial effect of captopril was reported. At last we analyse secondary effects of these drugs on the treatment of Heart Failure in old patients.


[Persistent ductus arteriosus in the adult--report of a case]. The authors describe a case of congenital heart disease no longer frequent in adults, due to an early diagnosis and surgical treatment. The patent ductus arteriosus in adults who received no therapy can present several forms of evolution, depending on its own hemodynamic profile. The present case is an example of a congenital heart disease not diagnosed during the childhood, that developed pulmonary hypertension and congestive heart failure. These clinical situations have a bad prognosis and place this patient in a group of high surgical risk. Thus, surgery is not advisable considering the bad prognosis and early high mortality rate.


[What is the value of myocardial perfusion studies with isotopes in patients with complete left bundle branch block?]. The prognosis of left bundle branch block is determined by associated cardiovascular disease. Exercise electrocardiography is not helpful in detecting ischemia in these patients. Exercise thallium-201 scintigraphy has been widely accepted for that purpose. The authors made an overview of several studies suggesting that exercise thallium-201 scintigraphy has low specificity regarding left anterior descending coronary artery disease. They also review the mechanisms of perfusion defects in patients with left bundle branch block without coronary artery disease. One important question to be clarified is weather small defects are unrelated to coronary artery disease. Finally the authors analyse a few methods to increase diagnostic accuracy of perfusion scintigraphy in left bundle branch block. First the employment of a new criterium that requires the apex to be abnormal to indicate left anterior descendent artery disease. Second Pharmacological Stress with Dipyridamole or Adenosine. Third imaging with Tc-99m-MIBI.


Ischemia, reperfusion and oxygen free radicals. Alterations which occur during ischemia are reviewed. They modify the metabolic status in such a way they prepare the cell to an anomalous response to reoxygenation. The consequence of this disturbance is the generation of oxygen free radicals through several mechanisms, including the mitochondrial oxidative phosphorylation, the arachidonic acid cascade, the activation of xanthine oxidase, activation of phagocytes, iron mobilization, etc. Reduced glutathione is exhausted, proteins are inactivated. Lipid peroxidation induces membrane breakdown and cellular death.


[Peri-ungual capillaroscopy in atherosclerosis]. The pathology of the major vessels also affects microcirculation, making possible to evaluate at the distal sector the consequences of an ischaemia, due to an artery disease, for instance. This work had as its main aim to evaluate by peri-ungueal capillaroscopy (PUC) the lesions due to an atherosclerotic process and the prognosis and/or diagnosis value of this exam. We studied 210 patients with either risk factors for atherosclerosis or atherosclerotic disease, who were divided into groups according to the severity of the lesions seen in PUC. Finally, we were able to conclude that although the capillaroscopic lesions found are not specific, they appear very early in the process and are more serious in the more severe cases.


[Transthoracic and transesophageal comparative echocardiography in mitral valve prolapse]. Transthoracic and transesophageal comparative analysis of functional and morphological abnormalities associated to idiopathic mitral valve prolapse (MVP). Prospective study. Outpatients with MVP diagnosis referred to echocardiographic laboratory of Cardiology Institute in Madrid, Spain. In each case we analyzed by TTE and TEE, anterior, posterior and double localization of MVP, number of prolapsed mitral leaflets/patient, total area of MVP to mitral valve plane, mitral annulus diameter, total area and spatial distribution of mitral regurgitation. TEE diagnosed a greater number of prolapsed mitral leaflets and a greater percentage of double (80%) MVP. MPV area by TEE (50 +/- 31 mm2) was considerably larger (96 +/- 30 mm2) than TTE MVP area (50 +/- 31 mm3. Associated mitral valve regurgitation area calculated through TEE was larger (558 +/- 502 mm2) than the same parameter evaluated by TTE (450 +/- 515 mm2). TEE is an efficient technique in MVP non invasive diagnosis and particularly sensitive to posterior MVP. Our data could be helpful in MVP cases scheduled for mitral valve repairment.


[Hypertensive reaction to exercise. Retrospective studies of 1363 consecutive exercise tests]. To study exercise hypertensive reaction and its relation with rest blood pressure, hypertension type and hypertensive cardiac disease. Retrospective study of treadmill exercise testes (ET) performed from January/89 to June/91: (n: 1703). Stress tests Laboratory of Cardiology Service of a Military Hospital. 1363 consecutive ET of male subjects, performing at least the 3rd stage of the Bruce protocol, were studied. From each ET record were obtained general data, including the reason for test, medication and the rest and exercise blood pressure. Exercise hypertensive reaction was defined as a Bruce protocol 3rd stage systolic blood pressure above 187 mmHg, which corresponds to mean +2SD of 130 normal male subjects previously studied. The Echocardiograms of non-treated hypertensives, obtained less than a month from ET, were reviewed. The diagnosis of borderline or moderate hypertension was base on the clinical records. 1) The 1363 ET included 132 (9.7%) ET to study hypertensive subjects, and 68 of these had hypertensive reaction. 86 ET were performed by non-treated hypertensive subjects, of whom 73 had Echocardiogram. 43 (3.5%) from 1231 ET performed by non-hypertensive subjects also had exercise hypertensive reaction. 2) The left ventricular (LV) mass index of non-treated hypertensive patients had a positive correlation with exercise systolic pressure (r: 0.45; p < 0.001), more important than with rest blood pressure or exercise systolic pressure response; there was a relation with LV wall thickness, but not with internal ventricular dimensions, that was only observed in hypertensive subjects that also had hypertensive reaction to exercise. 3) Exercise systolic blood pressure was usually normal in borderline and elevated in moderate hypertensives (Qui2: 27.249; p < 0.001). 4) Subjects with exercise hypertensive reaction, but not previously diagnosed as hypertensives, were usually true hypertensives. 1) Hypertensive peaks seem to be an important determinant factor in LV hypertrophy of hypertension, but its influence is felt only above a certain blood pressure threshold; it results on LV concentric type hypertrophy. 2) Exercise systolic blood pressure had a discrimination power of about 80% to separate borderline and moderate hypertensive subjects. 3) All subjects having an exercise hypertensive reaction must be carefully observed, even if their blood pressure at rest is normal, because most of them are true hypertensive patients.


[Infective endocarditis: analysis of 300 episodes]. Study of clinical features and etiologic agents, treatment and mortality of patients with infective endocarditis (IE). 300 episodes of IE occurring in 288 patients, ages ranged between 0.2 and 78 (mean 30.76) years; 185 (62%) episodes occurred in males. a) etiologic agents: viridans group streptococci in 93 (31%) episodes, enterococci en 21 (7%), group D-non enterococci in 19 (6%) (13 S. bovis), other streptococci in 14 (5%), Staphylococcus aureus in 59 (20%), Staphylococcus epidermidis in 14 (5%), gram-negative bacteria in 16 (5%), gram-positive bacteria other than streptococci and staphylococci and staphylococci in 8 (3%), fungi in 4 (1%). The etiologic agents were not identified in 52 (17%) episodes; b) underlying cardiac diseases: valvular heart disease in 119 (40%) episodes, congenital heart disease in 37 (12%), prosthetic heart valves in 69 (23%), other heart diseases in 6 (2%). There was no evidence of previous heart disease in 69 (23%); c) treatment: surgical treatment was undertaken in 102 (34%) episodes. The frequency of surgical treatment in relation to the etiologic agents ranged between 1% (non-group D streptococcus) and 62% (negative blood cultures). The frequency of operation in relation to underlying heart disease ranged between 17% (other heart diseases), 19% (congenital heart disease) and 54% (prosthetic heart valve); d) mortality: 78 (26%) patients died, 56 (28%) of the 198 submitted to medical treatment and 22 (21%) of the 102 submitted also to surgical treatment. The mortality in the different groups of etiologic agents ranged between 5% (non group D streptococcus) and 62% (gram-positive bacteria other than streptococci ans staphylococci); in relation to the underlying with other heart disease, 19% in valvular heart disease patients, 21% in patients with congenital heart disease, 23% in patients without known heart disease and 43% in patients with prosthetic heart valves. The mortality associated with IE remains still high in spite of modern treatment; the mortality is different in relation to the cardiac status before the IE.


Cholesterol embolization following coronary angioplasty. Cholesterol emboli syndrome is an uncommon complication seen after an invasive vascular procedure or surgery in a patient with atherosclerotic disease. The obstruction of small arteries by cholesterol crystals may be responsible for its clinical features, such as livedo reticularis, "purple toe" syndrome, renal failure, involvement of the gastrointestinal tract, coronary arteries, central nervous system or the multiple cholesterol emboli syndrome. Certain laboratory abnormalities are frequently associated: an elevated erythrocyte sedimentation rate and eosinophilia, BUN and creatinine increase in the cases with renal failure and creatine phosphokines augmentation suggesting muscle involvement. Disseminated microemboli composed mainly of cholesterol crystals are the usual pathological findings. A case of cholesterol embolism occurring after left heart catheterization and percutaneous transluminal coronary angioplasty is reported. Twenty-four hours after the procedure, the patient developed purplish discoloration of toes and soles, livedo reticularis on lumbar region, buttocks and limbs, and renal failure. Patient did well two months after anticoagulant therapy. Prognosis of these cases is related to the extent of systemic involvement and the most significant impact on this syndrome can be made by its prevention.


[Supraventricular tachycardia complicated by acute myocardial ischemia induced by atropine injection. Report of a clinical case]. The authors report a case of supraventricular tachyarrhythmia complicated by severe myocardial ischemia after IV injection of Atropine in a 37 years old woman, without known coronary artery disease. She had an ECG with sinusal bradycardia (40/min) and she was on the waiting list for to be submitted to surgical intervention on the lumbar spine.


[Role of pharmacologic stimulation with myocardial perfusion scintigraphy in the evaluation of patients with ischemic cardiopathy]. Exercise myocardial-thallium scintigraphy plays a fundamental role in the diagnosis of coronary artery disease. Once exercise is not always feasible, pharmacological stress became a possible alternative. The authors review the mechanism of action, administrations protocols, indications and side effects of the drugs used for this purpose: dipyridamole, adenosine and dobutamine. Dipyridamole causes coronary hyperemia by increasing the interstitial levels of endogenous adenosine. Perfusion defects result from the mismatch of coronary reserve in different coronary territories. The drug administration is classically performed with a 0.142 mg/kg/min dosage e.v. for 4 minutes, total of 0.56 mg/kg. It is possible to use a greater dose of 0.84 mg/kg e.v. for 10 minutes, increasing sensitivity without loss of specificity for diagnosis of coronary artery disease. Oral dipyridamole protocols with 300 and 400 mg were used with similar results for sensitivity and specificity. The oral protocol has the disadvantage of delayed onset and longer action. Including several dipyridamole studies, 87% was obtained for sensitivity and 84% for specificity, in the diagnosis of CAD. Dipyridamole scintigraphy has been applied to myocardial infarction risk stratification, cardiac risk evaluation of patients proposed to noncardiac surgery and therapeutic efficacy evaluation of reperfusion techniques (angioplasty and surgery). The secondary effects of dipyridamole are frequent, however mild and well tolerated. They occur in half the patients, the most frequent, facial flushing (2%), dizziness (5%), nausea (4%), vomiting (1%), headaches (11%) and chest pain (26%). Some important complications were reported although rare: myocardial infarction, ventricular fibrillation and bronchospasm.(ABSTRACT TRUNCATED AT 250 WORDS)


Relationship between ventricular arrhythmias and left ventricular false tendons in acute myocardial infarction. To evaluate the association between left ventricular false tendon (LVFT) and ventricular arrhythmias in acute myocardial infarction (MI) on the 1-st day of acute MI 71 patients were examined by 24-hour ECG-monitoring and M-mode, two-dimensional, Doppler echocardiography. LVFT was detected in 30 patients (42.3%). The frequency of left ventricular fibrillation, the number of patients with multiform ectopic ventricular beats (EVB), the number of single and pair EVB and runs of ventricular tachycardia were greater in group of patients with LVFT. 37 patients had Lown grades 1-2 (A) of arrhythmias, 34 patients had grades 3-5 (B). LVFT was revealed in four patients in group A (10.8%) and in 27 patients in group B (76.5%, p < 0.001). There were no significant differences between groups in left ventricular asynergy area and wall motion score, left and right ventricular, left atrium dimensions, left ventricular contractility indices, left ventricular walls thickness, frequency of mitral regurgitation. Multifactor analysis has shown significant relationship between Lown's class value and LVFT (p < 0.0001), Lown's class and arterial hypertension (p = 0.0376). Other 17 clinical factors were not connected with Lown's class value. Thus, LVFT was associated with severe ventricular arrhythmias in patients with AMI. This fact can be used as a predictor of these disturbances.


Scanning electron microscopic observations of the immunodefensive systems with special reference to the surface morphology of the non-lymphoid cells. This paper reviews scanning electron microscopic observations of cellular elements forming various lymphoid organs. The reticular cells in the secondary lymphoid organs are stellate, smooth-surfaced forms extending slender processes to comprise a three-dimensional network. The reticular fibers are usually covered by reticular cell processes, though they are naked in certain regions. Other types of reticular cells are observed in certain places: the "retothelial" type in the lymphatic sinus of the lymph nodes, and the "follicular dendritic" type in the germinal center of various lymphoid organs. The thymic epithelial cells are divided into two main types: stellate cells which form a three-dimensional meshwork throughout the thymus parenchyma; and large vacuolated cells located in the medulla. A continuous single layer consisting of the processes of the stellate epithelial cells separates the parenchyma from the connective tissues of the capsule, septa and vessels. The M cells in the epithelium of the gut-associated lymphoid tissues (GALTs) are cells with numerous irregular microprojections on the luminal surface. They often attach microorganisms to the luminal surface, reflecting their functions of antigen transport into the underlying lymphoid tissue. Lymphocytes of various shapes often cluster in the intercellular spaces under the M cells, a phenomenon believed to indicate direct stimulation of lymphocytes by certain transported substances. Macrophages are amoeboid cells independent of and unable to transform into reticular and endothelial cells, at variance with prerequisites of the reticulo-endothelial system concept. Multiple features of macrophages probably reflect the presence of the subpopulations as well as the phases of their activity.(ABSTRACT TRUNCATED AT 250 WORDS)


The myoepithelial and basal cells of ducts of human major salivary glands: a SEM study. The cytoarchitecture and distribution of myoepithelial (mecs) and basal (bc) cells of intralobular (intercalated, striated) and interlobular (excretory) ducts of human major salivary glands were studied by SEM through a variety of maceration and microdissection techniques. Intercalated ducts are covered by mecs which, unlike the large stellate cells of acini, are spindle shaped. Small star shaped mecs are rarely observed even in the most distal striated ducts, while no such cells are seen in excretory ducts. Basal cells form a more or less continuous row of small, basally placed cells in excretory ducts. Sparse bc are occasionally present in proximal striated ducts as well. Following microdissection, bc exhibit a cup-shaped apex which embraces the convex base of principal cells. This configuration may explain why, in TEM, bc seem to possess lateral processes which may be mistaken for mecs processes. Moreover, the lateral surfaces of bc do not exhibit the complex system of plasmalemma folds typical of principal cells. The present study demonstrates that fusate mecs are present in intercalated ducts and that basal cells are distinct from myoepithelial cells. These results may have some relevance in histogenetic studies of salivary gland neoplasms.


Scanning electron microscopy of the small intestine during gluten-challenge in celiac disease. The celiac disease syndrome is characterized by structural and ultrastructural alterations of the small intestine mucosa. According to criteria by European Society of Paediatric Gastroenterology and Nutrition, the conclusive diagnosis of celiac disease in children depends on the demonstration of histological relapse of the mucosa after reintroduction of gluten in the diet, as this syndrome is a permanent condition of gluten intolerance. Under these diseased conditions, the structure of the intestinal villi has been studied by light microscopy; morphological alterations were revealed only when the gluten challenge induced a clinical relapse. Scanning electron microscopy analyses of the intestinal mucosa in celiac diseased patients showed a strikingly uniform destruction of the villi with changes in their dimensions and arrangement. At high magnification the enterocytes were irregular in size and shape with a decrease and disruption of the glycocalyx. Reductions in length and density of microvilli were also clearly identified. Although these scanning electron microscopy findings could not demonstrate a relationship between the degrees of mucosal atrophy and the duration of the gluten challenge, they nevertheless revealed early stages of fine villous alterations that cannot be detected by the presently employed low resolution light microscopic techniques.


The "limiting ridge" of the rat stomach. In the rat, the forestomach is separated from the glandular stomach by a fold of the forestomach mucosa which generates the "limiting ridge" on the inner surface of the organ. This ridge overlaps a deep groove which is flanked proximally by the forestomach and distally by the glandular stomach. Light microscopy and scanning electron microscopy reveal that the keratinized squamous epithelium of the forestomach merges into the columnar epithelium of the glandular stomach at the bottom of the groove. Among the columnar cells of the distal wall of the groove are numerous brush cells. A remarkably thick lamina muscularis mucosae extends deep into the ridge. The peculiar architecture of the "limiting ridge" and the presence of numerous brush cells in its distal wall suggest that the region not only represents the transitional zone between forestomach and glandular stomach but that it might have a more specific function.


Ultrastructural features of the rabbit proximal tubules. The unique ultrastructure of the epithelial cells that line the entire length of the proximal tubule have been described. In particular, scanning electron microscopy has been used to illustrate the varied nature of the apical, lateral and basal surfaces of cells located along P1, P2 and P3. The functional implication of the highly specialized microanatomy of the basal cell surface remains an interesting area of investigation.


Three-dimensional visualization of renal cells by NaOH maceration. The three-dimensional fine structure of cells composing the renal tissue was demonstrated by SEM after the removal of extracellular matrices by NaOH maceration. This paper focuses on glomerular mesangial cells, Goormaghtigh's cells (extraglomerular mesangial cells), and epithelial cells in the thin limbs of Henle's loop in the rat, rabbit and dog. Mesangial cells reveal rough surfaces covered with short microvilli. The cells extend long branching processes in close association with the glomerular capillary, suggesting a role for them of regulating the capillary caliber. The mesangial cells interdigitate with each other by their microvilli, forming an intercellular labyrinth. Goormaghtigh's cells at the glomerular hilus are also covered with microvilli, which form narrow labyrinthine spaces between the cells. The labyrinth among the mesangial cells and that among Goormaghtigh's cells connect with each other at the hilus, giving rise to a channel system leading from the periphery of the glomerulus through the hilus to the interstitial space outside the glomerulus. Renal tubule cells display complicated intra- and intercellular interdigitations on the basal aspect. The pattern of epithelial interdigitation is specific to each tubular segment. The descending and ascending thin limbs of the long loops demonstrate a striking contrast to each other. The former is characterized by moderate intercellular interdigitation and by numerous microvilli on the lateral and basal surfaces; the latter is marked by elaborate, pectineal interdigitations, and by smooth basolateral surfaces.


The interface between epithelium and lamina propria in the rat urinary bladder. We investigated by transmission and scanning election microscopy the interface between the epithelium and lamina propria in the rat urinary bladder. A digestion technique that dissolves the basal laminae and collagen fibrils was effective in cleaving the mucosa at this level; the specimens were then prepared for scanning electron microscopy, thus visualizing the basal epithelial surface and the uppermost surface of the lamina propria. The underside of the epithelium is scored by very numerous grooves which in the intact organ are occupied by a dense network of blood capillaries. These vascular grooves allow a large number of capillaries (epithelial capillaries) to run at a distance of a few tenths of a micron from the epithelium. On the side of the lamina propria, after collagen and other extracellular materials had been removed, the capillary network itself is visible in the uppermost region. The network is complementary to that of vascular grooves. Other smaller grooves on the basal surface of the epithelium correspond to nerve fibres which run within a few tenths of a micron from the epithelium.


Three-dimensional analysis of the atrophic process of rat seminiferous tubules after estradiol treatment. Atrophic changes in the basal portion of the seminiferous tubules caused by daily injections of estradiol have been found by scanning electron microscopy disclosed after a digestion technique using collagenase and trypsin. In the control rat, the smooth basal portion of the epithelium was composed of polygonal Sertoli cells and reticularly-arranged ovoidal spermatogonia. After estradiol treatment, there appeared wavy furrows and ridges, and many folded micro-wrinkles in the complicated basal portion of the seminiferous tubules. The wavy furrows and ridges were repeatedly formed and appeared just like a cornice. These structures ran in an orderly manner perpendicular to the longitudinal axis of the tubules. In contrast, many micro-wrinkles ran in parallel to the longitudinal axis. These two structures had a characteristically similar size and orderly arrangement. They are discussed in relation to the mechanism by which the seminiferous tubules shrink by injections of estradiol.


Towards high resolution SEM of biological objects. The major task of biological high resolution SEM and TEM is to provide structural information for correlating structure and function. It is the only methodology with the inherent power needed to observe structures down to molecular dimensions within the context of complex biological systems. Specimen preparation and imaging techniques should therefore be directed towards the preservation and imaging of the smallest significant details in order to fully exploit this unique, integrating feature of biological electron microscopy, complementing the progress of the techniques used in cell biology, biochemistry, and molecular biology.


The three-dimensional architecture of the myosalpinx in mammals: an anatomical model for a functional hypothesis. Direct visualization of the three-dimensional architecture of the tubal musculature (myosalpinx) was made possible by a technique involving chemical digestion of interstitial connective tissue, followed by ultrasonic microdissection and final observations under the scanning electron microscope. The isthmic myosalpinx in the guinea pig, rabbit and in humans consists of muscular bundles that tend to lie longitudinally, circularly or oblique. The muscular bundles along the tubal wall change direction, branch and intermingle with one another, giving rise to an irregular network in which distinct layers are not readily distinguishable. In the ampulla, the muscle bundles form a very irregular three-dimensional network of fibres that follow different orientations. The authors suggest a primary role for such a structure in the random pendular transport of the gametes as well as in the denudation of the egg by deformation of the myotubal wall.


Scanning electron microscope investigations on the vaginal epithelium of the guinea pig during the estrous cycle. The present scanning electron microscope investigation describes the morphological changes occurring on the apical surface of the guinea pig vaginal epithelium during the estrous cycle. Dramatic changes can be observed at estrus in which the surface of the vaginal epithelium is covered by a distinct layer of mucous cells.


SEM studies on unmanageable hair.

SEM studies on unmanageable hair. The manageability of the hair is dependent on the surface composition of the hair shaft. Exogenously caused damage leads to unmanageability by massive superficial defects in the hair cuticle. The symptoms of trichorrhexis nodosa and trichoptilosis are present, and superficial horny scales are bent up and curve under in tunnel-like fashions. Appropriate hair care can improve these defects. Endogenous damage to the hair leading to unmanageability is characterized by spiral furrows along the shaft. It can not usually be improved by the use of care products. The examples presented in the paper demonstrate that exogenous and endogenous causes of unmanageability are characterized by different alterations in the hair shaft.


Ultrastructural organization of two tapetal types in angiosperms. The development of preparation techniques that include freeze fracturing provide an ideal method for studying the differentiation of plant tissues in the scanning electron microscope. This is illustrated with reference to tapetal development in Catananche caerulea, which has a plasmodial tapetum, and in Lolium perenne, which has a secretory tapetum.


The maceration technique in scanning electron microscopy of collagen fiber frameworks: its application in the study of human livers. This paper reviews the cell-maceration/scanning electron microscopic (SEM) technique and its application in the study of human livers. The maceration of glutaraldehyde-fixed tissues with 2N-NaOH and water at room temperature effectively and consistently removes all the cells, thus exposing collagen fiber networks. SEM of the macerated tissues shows three-dimensional arrangements of collagen fibers more clearly than previously reported methods. High resolution SEM observations of macerated and non-macerated collagen fibrils of the rat tail tendon have revealed that both show similar cross-striated bandings that are determined by an alternate succession of elevated and depressed segments along the collagen fibrils, with a period of approximately 65 nm. Three ridges have been observed in the nonmacerated collagen fibrils: two on the margins of the elevated segments and one at an intermediate point of the depressed segment. The macerated collagen fibrils show a straight arrangement with slightly wavy microfibrils. The subendothelial spaces of Disse in the human liver contain abundant collagen fibers. There are some collagen fibers that stretch between adjacent collagen fiber sheaths in the subendothelial spaces of Disse, either forming a mono-layered network or coursing individually. The collagen fibers in the spaces of Disse are continuous with those in the liver capsule and in the Glisson's sheaths and with those around the central and sublobular veins. The collagen fibers in human livers form a network of the liver as a whole, thus constituting a hepatoskeletal system.


A modified method for vascular casting and scanning electron microscopy: its utility in the demonstration of rat pancreatic insulo-acinar and other blood vascular systems. Monomeric methyl methacrylate resin, supplemented with 1.0% benzoyl peroxide and 1.0% N, N-dimethyaniline, enables good vascular casts useful for scanning electron microscopy when the injected organs or tissues are promptly heated in a microwave processor. The details of this vascular casting and scanning method are described with a clear demonstration of the rat pancreatic blood vascular bed, in particular, its intralobular, extralobular and translobular insulo-acinar portal systems and other vascular routes, including the insulo-venous vessels, which are sinusoidal in nature.


On the molecular profiling of cell surfaces by SEM. Cell surfaces interface with a variety of environments and, as a consequence, cell surface properties are of considerable functional importance to the biological organism. SEM immunocytochemistry (SEM-IC) is one of a range of techniques used to analyse cell surface properties. A major goal of SEM-IC centres on extended survey or high-magnification morphological analysis of cell and tissue surfaces combined with molecular profiles of these surfaces as established by gold-labelling. The properties of colloidal gold make it the marker of choice for SEM-IC and a representative gold-labelling protocol is outlined. The SEM-IC gold-labelling technique has been applied advantageously to the analysis both of cell surfaces and cytoskeletal and extracellular matrix elements: a tabulation of the main SEM-IC biomedical applications is given. Illustrated examples demonstrate how SEM-IC provides a highly effective approach for analysis both of cell and tissue differentiation-maturation sequences, and of pathological change involving not only the entire tissue or cell surface but also minute changes in microdomain characteristics of the individual cell surface. Steps in exploiting the technique of colloidal gold SEM-IC have been several-fold and include: use of backscattered electron imaging; accurate localization of gold particles by superimposition on topographical maps of the cell surface; and use of small (1-10 nm) gold probes followed by silver enhancement in order to minimize steric hindrance. Factors under assessment include: use of low voltage SEM; BE imaging of samples coated with ultrathin metal films; and use of gold-labelled SEM-IC for direct quantification of the numbers of target molecules exposed on cell surfaces by automated image analysis of the digitized BE image.


Scanning tunneling microscopic (STM) analysis of the phospholipid bilayer surface characteristics in the P beta phase. Secondary ripples. Previous investigations have elaborated on the necessity for dimyristoylphosphatidylcholine (DMPC) molecules to conform in a ripple phase at the temperature intermediate between the transition and pretransition in order to protect the hydrophilic-hydrophobic polarity of the bilayer. Present observations, in addition to the asymmetric P beta phase of 11.1 +/- 1.3 nm wave-length, demonstrate orthogonal corrugations perpendicular to the main wave direction. Whether this is a prerequisite for maintaining the molecular order-disorder balance at such specific temperature, or it results from yet unknown source is unclear at present.