Areas Of Rarefaction Research Articles

Manchas de Wischnewsky em casos de hipotermia fatal em bovinos

ABSTRACT: Wischnewsky spots (WS) are hemorrhagic, non-erosive, and non-ulcerative lesions that affect the gastric mucosa. They are considered common in the stomachs of humans who have died from hypothermia and are rarely described in other animal species. This study describes the occurrence of WS in cattle that had died of hypothermia in two cities in the state of Mato Grosso do Sul. Two properties were visited, and three cattle were necropsied by the team from the Pathological Anatomy Laboratory of the Federal University of Mato Grosso do Sul (LAP-UFMS). The epidemiological conditions and clinical signs of the cattle examined on both properties were similar. The deaths occurred on days when there was a sudden drop in environmental temperature, with continuous rain for more than 24 hours. During the visits, the most affected live cattle were found in sternal decubitus, with their heads resting on their flanks, or laterally in a comatose state, with nystagmus and a rectal temperature below 32°C. Macroscopically, there were multifocal to coalescent red and black areas on the mucosal surface of the abomasums of the three cattle necropsied, mainly at the apex of the folds, oval or punctate in shape, measuring 0.1 to 1.0cm in diameter. Microscopically, these dark areas corresponded to areas of rarefaction of the mucosal epithelial cells associated with hemorrhage and the frequent deposition of golden-brown pigment (hematin) in the extracellular medium. The diagnosis of hypothermia in cattle was based on epidemiology, clinical-pathological examination, and the exclusion of differential diagnoses. The lesions found in the abomasum of cattle that had died from hypothermia were compatible with WS, highlighting the importance of recognizing them in cases of cattle deaths in which this condition is suspected.

СOMPARATIVE CHARACTERISTICS AND SELECTION OF SPEED BEARINGS

The characteristics of bearing supports have been considered. Improving the efficiency of mechanical processing, the quality of operation of mechanisms that use sliding bearing supports, and ensuring stable operation are always important tasks. Solving these tasks contributes to reducing labor costs, reducing operating costs, and increasing the productivity of individual operations. The following main criteria are proposed for the selection of supports: the magnitude of the loads that supports can withstand; the range of allowable shaft rotation frequencies; accuracy in maintaining the position of the axis of shaft rotation; stability of shaft rotation (possibility of autooscillations and undesirable transient processes); energy costs and economic indicators of manufacturing and operation; vibroacoustic characteristics (noise level, sound level). The study of the movement of the working body that separates the friction pairs in the bearing is based on two fundamental laws of hydrodynamic lubrication theory: the law of mass conservation and the law ofmomentumconservation.Mathematicalmodels of supports with fluid lubrication, based on the Navier-Stokes equations, were used. The requirements for bearing supports are formulated on the basis of the tasks solved by the entire mechanism. The flow parameters of the working body affect the load-bearing capacity of radial bearings, and the proposed evaluation dependencies can also be used for tapered supports. The calculation results indicate a significant influence of the flow parameters of the working body on the expansion of the areas of rarefaction and the range of their values, as well as on the reduction of the area and range of increased pressures. It has been established that with small shaft eccentricities rotating at speeds of 60–70 m/s and with a radial clearance of 80 μm, the increase in load capacity can reach 20 %. An important qualitative feature has been identified: with an increase in the Reynolds number Re*, the load capacity of the bearing increases. The greatest intensity of changes in load capacity due to the influence of flow parameters of the working body is observed at a relative eccentricity of e = 0.2–0.4. The terms in the Navier-Stokes equation that take into account the parameters of the working fluid flow can have values that are comparable to other terms, so ignoring them is not always permissible.

Retinal microcirculation abnormalities in patients with systemic sclerosis: an explorative optical coherence tomography angiography study.

To investigate subclinical and clinical abnormalities in retinal and choroidal vascular plexuses in patients with SSc by means of optical coherence tomography angiography (OCT-A). A total of 20 consecutive SSc patients were recruited and compared with 20 healthy subjects. Quantitative analysis of vessel density (VD), choriocapillaris plexus flow index (CCP-FI) and choroidal vascularity index were performed on OCT-A images in the superficial capillary plexus (SCP), deep capillary plexus (DCP) and CCP for all patients. Images were further reviewed by two independent readers for the assessment of qualitative abnormalities, including tortuosity, rarefaction areas, megacapillaries and macular-foveal capillaries. The DCP-VD in the whole scan and in the perifoveal, superior, inferior, nasal and temporal regions was significantly lower in the SSc group. The CCP-FI was significantly higher in SSc patients. When comparing SSc patients with and without digital ulcers, significantly decreased SCP-VD was demonstrated in the whole, perifoveal, superior, inferior, temporal and nasal regions. No difference in any of the OCT-A parameters was observed when comparing patients with and without interstitial lung disease. Qualitative analysis of OCT-A revealed at least one abnormality in 95% of patients. We showed the ability of OCT-A to disclose early ocular vascular abnormalities in patients with SSc. Our results may represent a hypothesis-generating basis for exploring the potential role of OCT-A in diagnosis, monitoring and prognosis stratification in SSc.

Ультраструктурні зміни меланотропних клітин проміжної частки аденогіпофіза у віковому аспекті

In modern theoretical and practical biology and medicine, the key problem of research is to reveal the patterns of structural and functional organization of the human and animal body at different stages of development. Literature sources provide very limited data on the organization of the intermediate lobe of the adenohypophysis in humans, leaving insufficiently studied the ultrastructural state and activity of melanotropic cells of the intermediate lobe of the adenohypophysis in animals of different ages, including rats. The issues of the intermediate pituitary gland functioning remain important and little studied, especially in the period of the beginning of the optic-thalamic system. The purpose of the research was to study the ultrastructural changes of melanotropic cells of the intermediate lobe of the adenohypophysis in rats of different ages in the norm. Material and methods. In accordance with the purpose of the study we conducted the experiment on 30 nonlinear white male rats of different ages: 14-, 45- and 90-day-old. The animals were kept in the vivarium in equivalent conditions. The keeping and using of animals was carried out in accordance with the provisions of the "General Ethical Principles of Animal Experiments", approved by the IV National Congress of Bioethics. While examining the intermediate pituitary gland of intact rats on the electron microscope, the material was fixed in 2.5% solution of glutaraldehyde on phosphate buffer with fixation in 1% solution of osmium tetroxide according to Caulfield. It was dehydrated in alcohols of increasing concentration (70%, 80%, 90%, 100%) and acetone, poured into a mixture of epon-araldite. Semi-thin sections were made from the obtained blocks, which were stained with toluidine blue. Results and discussion. At the ultrastructural level in the intermediate lobe of the adenohypophysis of 14-day-old intact rats, several cell types could be identified that differed in the number and size of secretory granules. The ultrastructure of glandular cells of 45-day-old rats had no significant differences compared with 14-day-old animals. Secretory granules of different sizes and electron densities were observed in the cytoplasm of melanotropic cells. It was often possible to see a glandular cell with numerous secretory granules in one part of the cytoplasm, while in another they were virtually absent. Most melanotropocytes were characterized by slightly compacted mitochondria, but their numbers were slightly higher than in 45-day-old rats. The nuclei of most cells were large, oval in shape with a clear structure of nucleoli and their ribosomal component. The latter represented groups of ribosomes that were collected in osmophilic complexes. The amount of heterochromatin exceeded euchromatin and it was located mainly in the membrane with areas of rarefaction in the pore area Conclusion. In 14-day-old intact male rats, the intermediate lobe of the adenohypophysis was presented as a formed functionally active organ. In the ultrastructure of the cytoplasm of melanotropes there was a moderate development of organelles, and judging by the number and size of secretory granules, as well as the density of their content, we can assume that all these cells differed from each other in their functional activity. In 45-day-old intact rats, accumulation of secretory granules was observed in the cytoplasm of melanotropes, especially near the nucleus, which indicated an increase in melanocyte-stimulating hormones synthesis with age. The ultrastructural state of the cytoplasm and nucleus also indicated an increase in functional activity. The ultrastructure of the intermediate lobe cells of the adenohypophysis of rats at the age of 90 days differed from that of younger animals by signs of different functional activity of individual melanotropic cells

Systemic Mastocytosis Associated with "Smoldering" Multiple Myeloma.

A 79-year-old woman presented with a long history of peripheral eosinophilia. Previous right hemicolectomy for colonic polyposis was reported. Laboratory tests were notable for mild macrocitic anaemia and eosinophilia. β2 microglobulin and serum tryptase levels were elevated. Serum immunofixation revealed IgA/kappa monoclonal protein. Bence-Jones protein was positive. Bone marrow (BM) biopsy revealed the coexistence of two neoplastic components. Cohesive clusters of bland-looking, spindle-shaped mast cells, representing 20% of marrow cellularity, were close to aggregates of mature plasma cells occupying 40% of marrow cellularity. Molecular analysis on marrow aspirate demonstrated KIT D816V mutation, TET2 mutation, monoallelic deletion of TP53/17p13 and trisomy of ATM/11q23. A bone density study revealed mild osteoporosis. Full skeletal X-rays and magnetic resonance imaging (MRI) of spine and hips showed multiple, small rarefaction areas and an old L1-L2 fracture, both ascribed to osteoporosis. The association of systemic mastocytosis (SM) and multiple myeloma (MM) is very uncommon. The coexistence of SM with MM placed our patient in the SM with associated clonal haematological non-mast-cell lineage disease (SM-AHN) subtype. Midostaurin therapy was started.

A 34-year-old male with pain and mobility of upper left lateral incisor tooth

This article has no abstract. The first 100 words appear below: A 34-year-old male attended with mild pain during mastication and slight mobility on the upper left lateral incisor tooth for 2 months. He gave the history of trauma on the offending tooth 3 years ago and for this he visited to a local dentist 2 weeks ago but did not get any relief after treatment. On clinical examination, the tooth was non vital, tender to percussion with 2 degree mobility, not associated with any swelling and discharge. Pre-operative radiograph revealed obliteration of pulp chamber, area of rarefaction associated near the apex of upper left lateral incisor tooth, cervical radiolucency indicating the loss of periodontal structures and about 5 mm separated fragment of instrument in the coronal third of the root canal.

Calculation of lubricant flow in the slide bearing of the aviation engine reducer

A method has been developed for calculating the pressure distribution in a cylindrical slide bearing. We present the process of designing a heavy-duty slide bearing as a component of the reduction gearbox of a bypass turbojet engine as the object of our investigation. The process comprises the following stages: specification of the supporting structure; calculation of pressure distribution in the slide bearing for different eccentricities and angles of rotation of the shaft journal; calculation of the effect of shaft journal precession on pressure distribution; calculation of pressure distribution taking into account the channels of oil supply to the bearing. The results obtained in the experimental activities are given. The analysis carried out shows that the calculation helps to predict the location and size of pressure and rarefaction areas, to position the holes for oil supply, which will significantly improve the conditions of lubricant flow in the bearing.

Complicated Postoperative Course after an Incisional Biopsy of Metastatic Breast Cancer in the Mandible

Postoperative hemorrhage is a complication of metastatic carcinomas due to the microvasculature environment for cancer cell survival. A 50-year-old woman presented at the department of stomatology complaining of a 3-month duration, asymptomatic, swollen jaw, with no remarkable medical history. An intraoral examination revealed an ulcerated exophytic mass. A panoramic radiograph showed an area of rarefaction, with ill-defined margins, and bone destruction. An incisional biopsy was performed, with no complications during the surgery. After 2 days, the patient returned with a massive head and neck swelling due to a hemorrhagic edema, which was life threatening for the patient. A microscopic examination revealed a neoplastic population of duct-like structure formation with moderate pleomorphism and variable mitosis. The stroma was highly vascularized and hemorrhagic. Immunohistochemistry stains were positive for the estrogen receptor, progesterone receptor, GATA3, Ki-67, and negative for HER2. The final diagnosis was metastatic breast cancer. The patient is undergoing chemotherapy.

A Nonsurgical Technique for the Removal of Overextended Gutta-Percha

The present report describes and discusses a nonsurgical technique for the removal of overextended gutta-percha. Mechanical irritation results from overextension and the overextended material used during root canal obturation could produce an inflammatory reaction with an area of rarefaction in the periapical tissues. The healing process is not affected by the presence of filling materials as it is well tolerate by the periapical tissues, but it is accepted that a higher failure rate is found in overfilled teeth. This clinical report describes one case with an overextended gutta-percha cone and a new nonsurgical technique to remove this material. The technique described is a conservative, safe and plausible option to remove extruded gutta-percha in periapical area. Overextended gutta-percha cones could increase the failure of endodontic therapy. Commonly surgical procedures are indicated to remove this overextended material, but this nonsurgical technique could be a better treatment alternative and could increase the chances of success.

Radiotransparency of Polyvinylpyrrolidone-Hydrogel and Hydrogel Breast Implants: A Quantitative Analysis with Mastectomy Specimens

Breast cancer is the most common cancer in women. Past evidence suggested that women with silicone implants who had cancer presented with more advanced disease and had the worst prognosis due to difficulty visualizing early lesions on mammography. Hence, new filling materials have been developed. In this study, 10 mastectomy specimens were used. Mammograms of specimens alone and specimens covering polyvinylpyrrolidone-hydrogel and hydrogel implants were performed. The variables studied were number of mammograms necessary to examine each specimen, kilovolts and milliamperes of each mammogram, number of isolated microcalcifications, microcalcification clusters and macroscopic calcifications, and rarefaction areas. No significant differences were found in number of mammograms (p = 0.439), isolated microcalcifications (p = 0.178), macrocalcifications (p = 1.0), and presence of rarefaction areas (p = 0.368). The difference in number of microcalcification clusters was significant (p = 0.0498). Significant differences (p < 0.001) also were observed in the kilovolts and milliamperes of the mammograms performed for specimens alone versus those with implants. Polyvinylpyrrolidone-hydrogel and hydrogel breast implants allow adequate visualization of mammary glands at the expense of greater radiation doses, although it must be considered that the experimental situation does not fully match the real clinical setting.

The Fetal Brain in Bovine Viral Diarrhea Virus-infected Calves: Lesions, Distribution, and Cellular Heterogeneity of Viral Antigen at 190 Days Gestation

Previous studies have shown that the brain is a target of persistent infection with bovine viral diarrhea virus (BVDV) and have demonstrated viral tropism for neurons as well as other endogenous cell types in diverse brain areas. Apart from foci of mild residual inflammation in some postnatal calves, consistent brain lesions, per se, have not been reported. No similar comprehensive studies of the brain have been reported in bovine fetuses. In the current study, 12 BVDV-seronegative heifers were inoculated intranasally with a 2-ml 4.4 log(10) TCID(50)/ml dose of noncytopathic type 2 BVDV at 75 and 175 days of gestation to create persistently and transiently infected fetuses, respectively. In only persistently infected fetuses, encephaloclastic lesions resulting in pseudocysts were observed in the subependymal zone in the region of the median eminence and adjacent corona radiata as well as in the region of the external capsule associated with lenticulostriate arteries. Additionally, areas of rarefaction in white matter were observed at the tips of cerebrocortical gyri and in the external capsule. The distribution of viral antigen was examined by immunohistochemical labeling using the 15C5 anti-BVDV monoclonal antibody. Viral antigen was detected only in calves inoculated at 75 days of gestation, i.e., persistently infected. The pattern of BVDV immunolabeling revealed both similarities and differences compared with previous studies in postnatal calves, suggesting that viral infection in the brain is a dynamic and progressive rather than static process.

Behavior of Finite Volume Schemes for Hyperbolic Conservation Laws on Adaptive Redistributed Spatial Grids

In this work we consider finite volume schemes combined with dynamic spatial mesh redistribution. We study whether appropriate mesh redistribution is a satisfactory mechanism for increasing the resolution of numerical solutions for problems of scalar and systems of conservation laws (CL) in one space dimension, while being at the same time a stabilization mechanism for selecting the appropriate entropy solution. In order to increase the resolution around shock areas and keep the computational cost low, our redistribution policy is to reconstruct spatially the numerical solution on a new mesh, where the solution’s curvature is almost uniformly distributed, while the node’s cardinality is kept constant. We examine the stabilization properties of that redistribution process by adding it as a substep on the time evolution step of some classical schemes with known (unstable) characteristics. Testing the resulting method for several such schemes and on a large number of CL problems that have solutions with special characteristics (shocks, rarefaction areas, steady states) and comparing the results with those produced by schemes with extra stabilization mechanisms (like slope/flux limiters, entropy corrections), we conclude that indeed the proposed redistribution adds such stabilization properties while at the same time increasing the resolution.

The Incidence of Bacteremia in Endodontic Manipulation: Preliminary Report

Endodontic procedures have been under criticism by certain members of the profession for a long time, particularly as related to focal infection. Many still believe that pulpless teeth, especially those with an area of rarefaction, are a focus of infection which ultimately could produce a focal infection. The elimination of this possible focus of infection by conservative endodontic methods has been and still is questioned. Exodontic procedures, on the other hand, have never been censored. It is believed that removal of the tooth eradicates the focus and thereby eliminates the complication of a metastatic or focal infection. We should like to offer evidence that proper endodontic procedures can produce less likelihood of focal infection than exodontic procedures. It has been demonstrated clinically and experimentally that focal infection can develop as a result of a bacteremia (1) following extraction of teeth. The incidence of bacteremia as a result of exodontic and periodontal manipulation has been reported by numerous investigators (2–7). In the extraction of teeth, it has been shown that heavy trauma invariably produces a greater dispersal of microorganisms into the blood stream from the original focus. Therefore, the reduction of trauma can curtail the number of bacteria that enter the blood stream and thus prevent the complication of the development of certain organic diseases, particularly the dread subacute bacterial endocarditis in patients who have a history of rheumatic heart disease. Investigations of the relationship of endodontic procedures to bacteremia are very meager. Robinson and his group (5) did not detect the presence of bacteria in the blood in seven cases following reaming procedures and filling of the root canals. They did not state how many of each were done and whether or not cultures were taken of the root canals to determine the presence of microorganisms. In all instances they used the rubber dam. While many laboratory procedures were discussed, specific procedures for this series of cases were not given. Beechen and his group (8) found no evidence of positive blood cultures in pulpotomy procedures in one permanent molar and twenty-two deciduous molars. Their patients ranged in age from 4 to 11 years. The coronal portion of the pulp was cultured, and the organisms were identified in each case. They were able to obtain a 10 ml. sample of blood in their young patients. Ross and Rogers (9) treated six cases and found that in three cases of vital extirpation blood cultures were all positive, while in three cases of necrosis of the pulp they were all negative. They explain that the positive blood cultures were due to the organisms being carried into the blood stream through the pulpal circulation by means of the broaches and reamers as they traversed the infected portion of the carious process in the coronal portion of the pulp. The three cases of necrosis of the pulp produced negative cultures because there was no pulpal circulation to propel the bacteria into the blood stream. They did not take cultures of the coronal portion or root canals of the teeth tested. The following study was done to determine whether or not endodontic procedures can produce a bacteremia. If no bacteremias or a smaller incidence of bacteremias occur following endodontic procedures as compared to exodontic procedures, endodontics may be the treatment of choice, particularly for patients with valvular heart disease.

Unusual facets on the acetabulum in dry adult human coxal bones A morphological and radiological study

A smooth facet was found antero-inferior to lunate surface of 48 acetabula, in a study conducted on 315 dry adult coxal bones, 26 of which (13 pairs) were of articulated pelves. Three different shapes of the facet were oval (56.3%), piriform (22.9%) and elongated (20.8%). The prevalence of the oval facet was higher in both sexes. In 37.5% bones it extended to superior ramus of pubis and in 62.5% it was limited within the acetabular margin. They were either discrete (58.3%) or continuous with the lunate surface (41.7%). The surface configuration was flat (29.2%), concave (43.7%) or grooved (27.1%). One male articulated pelvis showed a bilateral presentation. Measured along the long axis the size varied between 11 to 17 mm. The radiographs showed notching, antero-inferior to acetabular margin in grooved facets whereas concave and flat facets were seen as areas of rarefaction. It is postulated that this facet could be a consequence of a particular posture which results in traction of the ligaments attached to this area. This unusual feature has not been reported earlier.

An Intraarticular Hip Process with Chondrolysis Simulating Perthes Disease: A Report of Five Cases

Radiographic findings in Legg-Calvé-Perthes disease (LCPD) are well known. Four classic stages have been described: incipient stage, avascular stage, fragmentation stage, and residual stage. Final femoral morphology is normally coxa magna, which is associated frequently with hypertrophy of the articular cartilage. We describe five patients with a hip process that initially presented clinical and radiographic findings compatible with LCPD. However, none of these patients showed the typical sequence of the radiographic stages. Instead, the early signs were the formation of rounded areas of rarefaction in the epiphysis and/or the metaphysis with considerable surrounding osteoporosis, early narrowing of the articular space, and final coxa breva morphology with signs of osteoarthritis. No condensation or fragmentation stages were observed. The pathologic study showed complete atrophy of the synovial villi with hyaline cartilage and bone necrosis. The patients described herein presented an intraarticular hip process, initially with signs and symptoms similar to LCPD but with an ultimate clinical evolution that differs from ordinary LCPD.

An intraarticular hip process with chondrolysis simulating Perthes disease: a report of five cases.

Radiographic findings in Legg-Calvé-Perthes disease (LCPD) are well known. Four classic stages have been described: incipient stage, avascular stage, fragmentation stage, and residual stage. Final femoral morphology is normally coxa magna, which is associated frequently with hypertrophy of the articular cartilage. We describe five patients with a hip process that initially presented clinical and radiographic findings compatible with LCPD. However, none of these patients showed the typical sequence of the radiographic stages. Instead, the early signs were the formation of rounded areas of rarefaction in the epiphysis and/or the metaphysis with considerable surrounding osteoporosis, early narrowing of the articular space, and final coxa breva morphology with signs of osteoarthritis. No condensation or fragmentation stages were observed. The pathologic study showed complete atrophy of the synovial villi with hyaline cartilage and bone necrosis. The patients described herein presented an intraarticular hip process, initially with signs and symptoms similar to LCPD but with an ultimate clinical evolution that differs from ordinary LCPD.

Radiotransparency of the Triglyceride Mammary Prosthesis: A Quantitative Analysis with Mastectomy Specimens

Breast cancer is the most frequent malignant tumor in women. It is estimated that 10 percent of women will present with a breast cancer during their lives. It is well known that mammography is the best technique for the early diagnosis of nonpalpable tumors, thus improving life expectancy. However, mammary prostheses may hide between 23 and 82 percent of the normal mammary tissue in mammography, and thus may delay the diagnosis of malignant mammary tumors, making prognosis worse. To solve this problem, oil-filled prostheses have been developed. In this study, 14 mastectomy specimens were used. Mammograms of the tissue pieces alone and also mammograms of the tissue pieces covering a 270-cc Trilucent prosthesis were used to verify whether the prosthesis allows observation of malignant signs in mammography. Mammograms were evaluated by an independent experienced radiologist. The following variables were studied: number of mammograms necessary to examine each specimen; kilovoltage and milliamperage necessary for each mammogram; number of microcalcification groups (malignant); number of macroscopic calcifications (benign); and rarefaction areas that were suspected for malignancy. All of these variables were measured for both mammograms for which the mastectomy specimens were covering and those for which the specimens were not covering the prothesis. Finally, the kilovoltage and milliamperage increases necessary to visualize the mammograms with mastectomy specimens covering the prosthesis were determined. Statistical analysis of the results obtained was performed. There were no significant differences in the number of mammograms (p = 0.391), the number of microcalcifications (p = 0.890), the number of macrocalcifications (p = 0.239), and finally in the presence of rarefaction areas (p = 1.000) observed in the mammograms in specimens either covering or not covering the prosthesis. However, there were significant differences (p < 0.001) between the kilovoltage and milliamperage applied to carry out the mammograms of specimens with and without the prosthesis. Thus, Trilucent prostheses allow visualization of the microscopic and macroscopic calcifications as well as rarefaction areas in mammograms. However, these mammograms required a higher kilovoltage and milliamperage compared with specimens not covering the prosthesis. To explore the whole gland, it might be necessary to perform two series of mammograms: one to detect the area shadowed by the prosthesis and one to observe the rest of the peripheral gland. (Plast. Reconstr. Surg. 104: 681, 1999.)

Radiotransparency of the triglyceride mammary prosthesis: a quantitative analysis with mastectomy specimens.

Breast cancer is the most frequent malignant tumor in women. It is estimated that 10 percent of women will present with a breast cancer during their lives. It is well known that mammography is the best technique for the early diagnosis of nonpalpable tumors, thus improving life expectancy. However, mammary prostheses may hide between 23 and 82 percent of the normal mammary tissue in mammography, and thus may delay the diagnosis of malignant mammary tumors, making prognosis worse. To solve this problem, oil-filled prostheses have been developed. In this study, 14 mastectomy specimens were used. Mammograms of the tissue pieces alone and also mammograms of the tissue pieces covering a 270-cc Trilucent prosthesis were used to verify whether the prosthesis allows observation of malignant signs in mammography. Mammograms were evaluated by an independent experienced radiologist. The following variables were studied: number of mammograms necessary to examine each specimen; kilovoltage and milliamperage necessary for each mammogram; number of microcalcification groups (malignant); number of macroscopic calcifications (benign); and rarefaction areas that were suspected for malignancy. All of these variables were measured for both mammograms for which the mastectomy specimens were covering and those for which the specimens were not covering the prothesis. Finally, the kilovoltage and milliamperage increases necessary to visualize the mammograms with mastectomy specimens covering the prosthesis were determined. Statistical analysis of the results obtained was performed. There were no significant differences in the number of mammograms (p = 0.391), the number of microcalcifications (p = 0.890), the number of macrocalcifications (p = 0.239), and finally in the presence of rarefaction areas (p = 1.000) observed in the mammograms in specimens either covering or not covering the prosthesis. However, there were significant differences (p < 0.001) between the kilovoltage and milliamperage applied to carry out the mammograms of specimens with and without the prosthesis. Thus, Trilucent prostheses allow visualization of the microscopic and macroscopic calcifications as well as rarefaction areas in mammograms. However, these mammograms required a higher kilovoltage and milliamperage compared with specimens not covering the prosthesis. To explore the whole gland, it might be necessary to perform two series of mammograms: one to detect the area shadowed by the prosthesis and one to observe the rest of the peripheral gland.

Diffuse leiomyomatosis of the esophagus: disorder of cell-matrix interaction?

Diffuse leiomyomatosis (DL) is rare condition characterized by proliferation of smooth muscle in the upper gastrointestinal tract. Most cases are associated with X-linked Alport syndrome and have partial deletions in the genes encoding both the alpha5 and alpha6 chains of collagen type IV. We studied aspects of cell-matrix interaction of myocytes in an esophagogastrectomy specimen from a 12-year-old patient with DL. Myocytes had central areas of cytoplasmic rarefaction, which were actin positive and desmin poor, with the reverse pattern of staining at the cell periphery. Electron microscopy (EM) showed that the areas of rarefaction consisted of disorganized aggregates of filaments. The basement membranes ranged from thickened to thinned or absent. Immunohistochemical staining for the alpha1-alpha4 chains of collagen type IV, the alpha1, alpha2, beta2, and gamma1 chains of laminin, nidogen, type VI collagen, and fibronectin was normal. There was loss of the alpha5 and alpha6 chains of collagen type IV and the beta1 chain of laminin. Normal staining for alpha1, alpha2, alpha3, alpha4, alpha6, alpha8, and beta1 integrins was noted. Staining for alpha5 integrin varied from normal to reduced or negative in different cells. In DL, a primary abnormality of basement membrane may be associated with disorganization of the contractile apparatus and alterations of certain integrins. This may reflect a disturbance of cell-matrix interactions that play a role in cell differentiation and internal organization.

Age-related changes in elastic fibers of human heart.

The effects of age on the human heart elastic fibers were studied by light and electron microscopy. Studies were done on 15 hearts from male subjects 42 days to 87 years of age. Using specific staining procedures, the length of elastic fibers was determined by morphometry in the parenchyma of right and left ventricles. These studies suggest that the length of elastic fibers per unit heart volume is present early in life, possibly at birth, and thereafter remains constant until adulthood. Average fiber length increases significantly beyond the third decade of life which can be interpreted as a continuous formation of new fibers and a continuous apposition of elastic-type material to these fibers. Electron microscopy confirmed the presence of mature elastic fibers at birth, since they contained amorphous substance (elastin) surrounded by numerous microfibrils. In the adult hearts, the amount of amorphous substance has increased and the number of microfibrils has decreased. With advancing age the amorphous substance forms areas of rarefaction and the microfibrils have disappeared. Whether or not such morphometric modifications could influence the elastic properties of the ventricular myocardium requires further study.