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A case of cardiac myxoma with glandular differentiation is reported. The patient did not have elements of the Carney triad or syndrome. The tumor was mainly composed of characteristic stellate cells in a focally collagenized, myxoid stroma, along with aggregates of glandular-forming epithelial cells, with mucin-containing intra- and intercellular lumina. Ultrastructurally, these gland spaces displayed short, straight microvilli and junctional complexes. The epithelial cells were positive for cytokeratin 7 and negative for cytokeratin 20. Calretinin was positive in the stellate cells and negative in the epithelial component. The potential origin from pluripotent mesenchymal cells or from seeded stem cells is hypothesized for glandular differentiation in myxomas. Further studies are required to unravel the relationship between stellate cells and the diverse heterologous components reported in these tumors. [ABSTRACT FROM AUTHOR]

Muscle abnormalities involved in chronic obstructive pulmonary disease (COPD) or the changes leading to muscle wasting and cachexia in neoplastic patients have a remarkable clinical impact, but their study is complex and findings are sometimes paradoxical. In this review, the main factors influencing muscle wasting and muscle abnormalities found in chronic diseases such as COPD are regarded in the light of a comprehensive approach. All this changes work in a complex, multifactorial manner, and experimental or observational approaches must take this fact into consideration. Two concepts that may be helpful in this regard are the “muscle compartment theory,” by which different muscle groups, individual muscles, or muscle areas may react differently to a variety of stimuli and pathogenic factors, and the “oil well analogy,” which reflects the complexity and variability of the energy resource depletion mechanisms in cells and tissues, leading to structural remodeling and functional adaptation or impairment. [ABSTRACT FROM AUTHOR]

Molecular studies on whole samples of fresh or frozen tissue do not take into account the heterogeneity of these tissues. In addition to normal cells, precursor lesions and different progression stages may be mixed within a given sample. Usually, the dominant cell population will determine the results and may sometimes mask biologically relevant abnormalities. To obtain more specific information and knowledge on changes within different cell compartments, many techniques have been developed that combine morphological observation and selection with different strategies for specific cell dissection. In this review, the most important micro-dissection methods are put into perspective, and some requirements and limitations are discussed with regard to sample fixation, staining, dissection and molecular analysis. [ABSTRACT FROM AUTHOR]

Clear cell meningioma (CCM) is a peculiar variant that differs from conventional meningioma in affecting younger patients, arising more often in spinal or cerebellopontine locations, and showing a higher recurrence rate. Classical meningothelial areas are scarce in these tumors and the differential diagnosis with other neoplasms, particularly metastatic carcinoma, is often difficult. We report a case of clear cell meningioma from the lumbosacral spine in which location, radiologic presentation, light microscopic appearance in initial sampling, and some of the ultrastructural findings were reminiscent of chordoma. The tumor cells were diffusely positive for vimentin and very focally positive for epithelial membrane antigen. Ultrastructural demonstration of interdigitating cell processes joined by numerous desmosomes confirmed the diagnosis of CCM. [ABSTRACT FROM AUTHOR]

Cells having a signet ring appearance can occur in mesenchymal, lymphoid, and other nonepithelial neoplasms. We report the case of an intestinal stromal tumor with smooth muscle differentiation and a prominent signet ring cell component. The presence of signet ring forms of smooth muscle cells in sections of paraffin-embedded tissue often contrasts with a lack of cytoplasmic spaces by electron microscopy, and the ultrastructural finding of signet ring-like areas in the present case can be attributed to the fact that the tissue for electron microscopy was retrieved fromparaffin blocks where this peculiar artifact already existed. Ultrastructural examination of the signet ring-like areas suggests that they originated as retraction spaces which may have resulted from variations in intracellular tension forces related to the distribution of actin filaments. [ABSTRACT FROM AUTHOR]

The article discussed a study by Ye Min and colleagues titled "Vesiculo-Cystoid Structures Associated with Nuclear Pseudoinclusions in the Nuclei of Liver Cells." The author details the results of the electron micrographs provided by Ye Min and colleagues in the study. He recommends a technique to characterize the chemical nature of these structures.

Information about several topics discussed at a symposium conducted by the Renal Pathology Society and the Society for the Ultrastructural Pathology held in March 2006 in Atlanta, Georgia. Issues that were dealt with included the consideration of electron microscopy as an important research material. It also contemplated on the theory of renal pathologist Conrad Pirani to provide health care to patients with renal diseases through critical ultrastructural analysis.

Muscle injury has clinical relevance in diseased individuals because it is associated with muscle dysfunction in terms of decreased strength and/or endurance. This study was aimed at answering three questions: whether the presence of chronic obstructive pulmonary disease (COPD) is associated with peripheral muscle injury; whether muscle injury is associated with some of the relevant functional impairment in the muscles; and whether muscle injury can be solely justified by deconditioning. Twenty-one male COPD patients were eligible for the study. Seven healthy volunteers recruited from the general population were included as controls. Function of the quadriceps muscle was assessed through specific single-leg exercise (strength and endurance). Cellular (light microscopy) and subcellular (electron microscopy) techniques were used to evaluate muscle injury on biopsies from the vastus lateralis muscle. Signs of injury were found in muscles from both control and COPD patients, not only in cases showing severe airflow obstruction but also in the mild or moderate stages of the disease. Current smoking and presence of COPD were significantly associated with increased injury of the muscle as assessed by light and electron microscopy techniques. The authors conclude that peripheral muscle injury is evident in mild, moderate, and severe stages of COPD even in the absence of respiratory failure, hypercapnia, chronic steroid treatment, low body weight, or some coexisting disease. These findings support the theory that systemic factors with deleterious effect are acting on peripheral muscles of smokers with COPD, increasing the susceptibility of the muscle fibers to membrane and sarcomere injury. [ABSTRACT FROM AUTHOR]

Objective. Functional gastrointestinal disorders (FGID) may appear after acute gastroenteritis. The aim of this study was to evaluate the possible mechanisms (inflammation, visceral hypersensitivity, psychological and immunogenetic factors) related to the development of postinfectious (PI) FGID 3 years after a Salmonella outbreak. Material and methods. Biopsies of the antrum, and right- and left colon from 16 PI-FGID patients, 8 PI control patients, and 18 healthy controls (H-controls) were processed for immunohistochemistry, cytokines, and mast-cell electron microscopy. DNA was typed for cytokine gene polymorphisms. Visceral sensitivity (satiety test and rectal barostat) and psychological factors (SCL-90 and vital events) were assessed. Results. The number of mast cells and T lymphocytes was similar among the groups in all locations. Mast cells within 5 µm of nerve fibers of both PI groups were increased compared to H-controls: (stomach: 5.6±1.2 versus 6.6±1.5 versus 2.5±1.1; right colon: 9.7±1.3 versus 8.0±1.3 versus 4.1±1.7; left colon: 8.9±0.9 versus 8.5±1.8 versus 2.2±2.0 per field) (p<0.05). No differences in the production of IL-1β, IL-1ra, IL-6, and IL-10 or in their genotypes were found. PI-FGID patients showed a lower pain threshold to rectal distention (29±2 versus 37± 2 mmHg; p<0.05). Scores for anxiety (0.63±0.11 versus 0.28±0.14) and somatization (1.01±0.15 versus 0.45±0.15) were higher in PI-FGID patients than in PI controls (p<0.05). The number of stressful life events was not significantly different between both PI groups. Conclusions. Three years after salmonellosis, PI-FGID patients showed no evidence of inflammation in the gastric or colonic mucosa, but visceral sensitivity and anxiety/somatization levels were increased. The close anatomical mast cell-nerve fibers relation does not seem to be related to the FGID but to the infection itself. [ABSTRACT FROM AUTHOR]