Pulmonary alveolar septal amyloidosis. A scanning- and transmission electron microscopy study

A case of primary amyloidosis is presented with diffusely involved the alveolar septa. The lung was studied by light microscopy and by transmission and scanning electron microscopy. The fine structure of the amyloid material showed it to be porous, homogeneous, and an acellular substance consisting of interwoven bundles of amyloid fibrils. The fine structure of the amyloid material was considered to explain the normal gas diffusion across the alveolar respiratory membrane. The diagnosis of amyloidosis was first made from a uterine cervical biopsy specimen.     

Nickel and gold in skin lesions of pierced earlobes with contact dermatitis. A study using scanning electron microscopy and x-ray microanalysis

OBJECTIVE: To make an analysis of fungemia in HIV-infected patients in our hospital. PATIENTS AND METHODS: We retrospectively (1989-1997) studied all HIV-infected patients with positive blood cultures for Candida sp., Cryptococcus neoformans or any other fungal infection. RESULTS: C. neoformans was isolated in 11 patients (10 men and 1 woman): Six were treated with amphotericin B and 5 with fluconazole. 2 patients died during the acute phase and the infection relapsed in 3. Blood culture for Candida sp. were positive in 9 (8 men and 1 woman): only a case was nosocomial. Seven patients were intravenous drug users and the presenting manifestations were autolimited candidemia in 3, aortic and tricuspid endocarditis in 1 and 2 cases respectively and pneumonia in another one. Six C. albicans, 2 C. krusei and 1 C. glabrata were isolated. 3 patients received amphotericin B and 3 received fluconazole. 2 patients suffering from endocarditis died and so did the patient with C. glabrata infection. A patient, who denied having travelled to endemic areas, developed histoplasmosis; blood culture was positive for H. capsulatum. He initially had a good response to amphotericin B and itraconazole. CONCLUSIONS: Fungemia is not frequent in HIV-infected patients. Cryptococcosis and histoplasmosis occur in advanced HIV-patients and candidemia is fundamentally associated with intravenous drug use.     

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

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

A study of the interface between bone and acrylic cement by scanning electron microscopy

The influence of different pretreatments upon locomotor stimulation, induced by injection of ergometrine into the nucleus accumbens of rats, was investigated. The noradrenergic antagonists phenoxybenzamine and propranolol and the serotonin antagonist methysergide produced no clear changes. Reserpine, alone or in combination with alpha-MPT, considerably shortened the delay between injection of ergometrine and start of locomotor stimulation. Ro-DOPA, but not Ro-5-HTP, clearly antagonized the locomotor stimulation. The effect of ergometrine was strongly diminished following injection of haloperidol directly into the nucleus accumbens. A strong inhibition was also observedfollowing intracerebral administration of the imidazoline derivative (3,4-dihydroxy-phenylamino)-2-imidazoline (DPI), but not after injection of the structurally related compound clonidine. DPI by itself and also the ergot derivatives ergocornine, bromocryptine, LSD, dihydroergotamine and methysergide in doses 5--10 times as high as that of ergometrine failed to produce locomotor stimulation following injection into the nucleus accumbens. The results are discussed, especially with regard to the role of dopamine.     

Sintering study of silver particles by in situ electron microscopy

Micron size silver spherical particles were sintered in the hot stage of an electron microscope between 370 and 720°C. In the 370 to 520°C temperature range, sintering can be explained either by grain-boundary diffusion or dislocation slip. At higher temperatures, the controlling mechanism changes from surface or grain-boundary diffusion to volume diffusion from 570 to 720°C. These conclusions are based on observations of neck growth and shrinkage and on analyses of the shapes of the sintering curves.     

An electron microscopy study of chip formation

Chip formation or metal cutting is a unique large strain, high strain rate plastic deformation process. Almost all the previously reported studies of chip formation have examined the problem from the point of view of the mechanics of the deformable bodies using the mathematical theory of plasticity. This study, recognizing the heterogeneous nature of chip formation as encountered in course of machining metals, examines the problem from the metal physical or metallurgical view point. Electron microscopy studies were carried out on steel as well as nonferrous metal chips produced by shop machining conditions and compared to those chips produced by ultramicrotomy. This thin film orthogonal cutting process was employed to produce chips for microscopic examinations under well controlled and repeatable experimental conditions. The experiments carried out were designed to clarify the details of the heterogeneous plastic deformation activity occurring on the microscopic level during machining. The morphological (external surface) characteristics of the chips observed with the scanning electron microscope were correlated with the internal, dislocated structure of the chips observed by transmission electron microscopy methods. The effect of a stacking fault energy (SFE) change in an Ag-Sn alloy on chip thickness ratio(ν _t) is presented for the first time, demonstrating that this deformation process is sensitive to changes in SFE. The essentially discontinuous nature of the chip formation process observed by scanning and transmission electron microscopy is analyzed with a model involving dynamic dislocation behavior in a metal in the presence of large energy dissipation arising from plastic flow to account for the observed instability. N. Y. J. T. BLACK, formerly with the Department of Mechanical Engineering, University of Vermont, Burlington Vt.     

A juxtaglomerular cell tumor. Analysis of immunohistochemistry, electron microscopy and in situ hybridization

We investigated the prognosis of completely resected 119 non-small cell lung cancer patients according to the invaded organs. There was no significant difference in prognosis between T3N0M0 and T3N1M0 patients (5-year survival rate: 34% vs. 38%). However, the prognosis of T3N2M0 patients (5-year survival rate: 11%) was too poor to be regarded as the same category. Therefore, we investigated only T3N0M0 and T3N1M0 patients to assess the contribution of the invaded organs to prognosis. Of the 5 patients with diaphragm invasion, there was no 3-year survivor, and the prognosis of patients with diaphragm invasion was very poor. The chest wall invasion was divided into three parts: parietal pleural invasion, subpleural tissue invasion and intercostal muscular invasion. The 5-year survival rates of patients with such invasion was 35%, 29% and 27%, respectively. The patients with Pancoast tumor had very poor prognosis. T3 factor was heterogeneous, and the prognosis of the patients with T3 tumor was various according to invaded organs.     

In vitro study of the process of urinary calculi fragmentation with endoscopy, light microscopy, and scanning electron microscopy

Stones with different compositions respond differently to shock wave lithofragmentation. Likewise, the various lithotrity systems used may have different effects on the stones. To determine the relationships between stone composition and their fragmentation patterns, we conducted an in vitro study using endoscopy, magnifying glass, light microscope and scanning electron microscope on fragments obtained after lithotrity of 60 pure stone with different compositions: calcium oxalate monohydrate and dihydrate (OXMH and OXDH), phosphocarbonate (PC), ammonium magnesium phosphate (AMF) and uric acid (UA). Fragmentation was carried out with 4 different lithofragmenting sources (electrohydraulic, piezoelectric, ultrasound and pulse laser). No morphologic differences in the fractures induced by the various lithofragmenting sources were demonstrated. OXMH and UA stones basically break up by intercrystalline fracture and splitting of their concentric plates. OXDH breaks up mainly by intercrystalline fractures aided by the fibrillar organic material and phosphocarbonates found in the intercrystalline spaces. Fragmentation in infective stones (AMF and PC) occurs across the intercrystalline surfaces and by intracrystalline fracture. Ammonium urate fragments break up by intracrystalline fractures that run across the equatorial plane of its characteristic acicular microspheres.     

Cardiac rhabdomyosarcoma: a clinicopathologic and electron microscopy study

The use of imaging techniques including gamma scintigraphy to follow the behaviour of drug formulations has revolutionized our knowledge of absorption and distribution in drug delivery. The development of gamma camera techniques as physiological tools to explore organ function became routine by the mid-seventies. Several research groups started to explore the applications of technique in drug delivery. Within 5 years, the utility of the technique became obvious and scintigraphy is now widely accepted as an important investigation tool in formulation research. Gamma scintigraphy is especially useful in exploring sources of inter-subject variation, especially in examining food effects in pharmacokinetic estimations and establishing windows of absorption for oral delivery. As a tool to examine drug delivery to the lung and to the eye, scintigraphy is the method of choice. Magnetic Resonance Imaging (MRI) became more generally employed in medicine two decades after the gamma camera. The superior soft-tissue contrast and resolution compared to computed X-ray tomography rapidly established MRI in clinical investigation. Recent applications in oral drug research has allowed the pharmaceutical scientist to explore new facets of delivery and ultimately combine MRI and scintigraphy in human clinical trials.     

A scanning electron microscopy study of Taxus leaves as related to taxonomy

Scanning electron microscopy, when applied to the surfaces of the needles of Taxus spp. (yew) revealed features that appear useful in the taxonomy of this tree species which yields the important anticancer drug, taxol. For instance, all of the four North American species have 3-5 rows of stomata on one-half of the abaxial leaf surface, whereas all of the others, including those from Europe and Asia, have 7-10 rows of stomata. The appearance of individual or fused papilliform epidermal cells and their arrangement on the leaf surface also is a feature that varies between species. Patterns of wax formation appeared on all species of yew examined but none could characteristically be assigned to a given species. Wax pattern variation was dependent upon age, environment, and probably to some extent, species differences. This study may provide some additional useful and reliable indicators in Taxus taxonomy.     

Crystallographic study of the tempering of martensitic carbon steel by electron microscopy and diffraction

Structural changes taking place during the tempering proceed in four stages. At the preliminary stage taking place below 370 K, interstitial carbon atom clusters are formed below 270 K, rearrange to make a modulated structure between 270 and 360 K, and disappear at about 370 K. A long period ordered phase with respect to the interstitial carbon atoM_s or interstitial vacancies also appears between 330 and 350 K. With the disappearance of these structures, the first stage takes place between 370 and 470 K, where η-Fe₂C is formed in the matrix of low carbon martensite. The second stage o°Curs around 550 K with the retained austenite decomposing to θ-Fe₃C and α iron. At the su°Cession of the first stage, the third stage appears in a temperature range from 470 to 900 K, where θ-Fe₃C,X-Fe₅C₂ and also higher carbides θ_n-Fe_2n+1C_n intergrow microsyntactically in the particles precipitated below 720 K, but only θ-Fe₃C is formed above this temperature. Y. HIROTSU formerly Research Associate of Tokyo Institute of Technology. T. SUZUKI formerly Graduate Student of Tokyo Institute of Technology This paper is based on a presentation made at the “pcter G. Winchell Symposium on Tempering of Steel” held at the Louisville Meeting of The Metallurgical Society of AIME, October 12-13, 1981, under the sponsorship of the TMS-AIME Ferrous Metallurgy and Heat Treatment Committees.     

A practical method for identifying intermetallic phase particles in aluminium alloys by electron probe microanalysis

Aluminium alloys that contain Si, Mg, Fe, Mn and/or Cu usually contain one or more types of intermetallic phases that are not readily distinguishable in the microstructure by conventional microscopy methods. It has thus been a challenge to develop a method that will unambiguously identify them. A practical approach has been developed that is based on an inherent linear relationship revealed for the overall distribution of any two elements in a precipitate/matrix geometry and the first-order approximation of electron probe microanalysis (EPMA) results. Application of this approach to a direct chill cast 6082 alloy is demonstrated, and its major limitations are discussed.     

Structural studies of fibrinolysis by electron microscopy

Fibrin is degraded by the fibrinolytic system in which a plasminogen activator converts plasminogen to plasmin, a serine protease that cleaves specific bonds in fibrin leading to solubilization. To elucidate further the biophysical processes involved in conversion of insoluble fibers to soluble fragments, fibrin was treated with either plasmin or the combination of plasminogen and plasminogen activator, and morphologic changes were observed using scanning electron microscopy. These changes were correlated with biochemical analysis and with characterization of released, soluble fragments by transmission electron microscopy. Initial changes in the fibrin matrix included creation of many free fiber ends and gaps in the continuity of fibers. With more extensive digestion, free fiber segments associated laterally, resulting in formation of thick fiber bundles. Supernatants of digesting clots, containing soluble derivatives, were negatively contrasted and examined by transmission electron microscopy. Large, complex fragments containing portions of multiple fibers were observed, as were pieces of individual fibers and smaller fragments previously identified. Some large fragments had sharply defined ends, indicating that they had been cleaved perpendicularly to the fiber direction. Other fibers showed splayed ends or a lacy meshwork of surrounding protofibrils. Longer times generated more small fragments whose molecular composition could be inferred from their appearance. These results indicate that fibrinolytic degradation results in larger pieces than previously identified and that plasmin digestion proceeds locally by transverse cutting across fibers rather than by progressive cleavage uniformly around the fiber.