Archives of pathology & laboratory medicine
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Arch. Pathol. Lab. Med. · Apr 2011
International normalized ratio versus plasma levels of coagulation factors in patients on vitamin K antagonist therapy.
The key question when managing patients on warfarin therapy who present with life-threatening bleeding is how to use the international normalized ratio (INR) to best direct corrective therapy. The corollary question for the clinical laboratory is at what level will the INR reflect a critical value that requires notifying the clinician. ⋯ Levels of factors II, VII, IX, and X declined with increasing INR but not at the same rate and not to the same level at a given INR. However, most of the values were below the hemostatic value once the INR was 3.6 or more, the level that was also considered critical for physician notification.
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Practicing pathology in a resource-poor setting presents many challenges that are unfamiliar to pathologists in developed countries. Typically, the number of pathologists in a resource-poor country is small, even as a percentage of the total medical workforce. Although pathology should play a central role in the delivery of appropriate health care to the patient, this role is often hidden and not well recognized by patients, clinical colleagues, or other stakeholders, such as administrators and politicians. ⋯ The pathologist plays a key role as an educator in developing countries to medical students, allied health professionals, and medical colleagues and is, therefore, called upon to provide many hours of teaching. The pathologist is uniquely qualified to provide knowledge and understanding regarding the diseases in the region where he or she practices. Although many of these challenges are universal, they are perhaps nowhere more acute than in resource-poor settings.
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Lymphangioleiomyomatosis is an uncommon lung disease primarily affecting women of childbearing age. It is characterized by the progressive proliferating and infiltrating smooth musclelike cells (lymphangioleiomyomatosis cells), which lead to the cystic destruction of the lung parenchyma; obstruction of airways, blood vessels, and lymphatics; and loss of pulmonary function. ⋯ Somatic or genetic mutations of tumor suppressor genes tuberous sclerosis complex (TSC) 1 or TSC2 are closely related to lymphangioleiomyomatosis. The TSC1/TSC2 protein-related signaling pathways are involved in the pathogenesis and may provide novel therapeutic targets for lymphangioleiomyomatosis and diseases associated with TSC1 / TSC2 dysfunction.
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Interest in pathologist-performed ultrasound-guided fine-needle aspiration is increasing. Educational courses discuss clinical ultrasound and biopsy techniques but not ultrasound physics and instrumentation. ⋯ Ultrasound physics and instrumentation are the foundations of clinical ultrasound. The key physical principle is the piezoelectric effect. When stimulated by an electric current, certain crystals vibrate and produce ultrasound. A hand-held transducer converts electricity into ultrasound, transmits it into tissue, and listens for reflected ultrasound to return. The returning echoes are converted into electrical signals and used to create a 2-dimensional gray-scale image. Scanning at a high frequency improves axial resolution but has low tissue penetration. Electronic focusing moves the long-axis focus to depth of the object of interest and improves lateral resolution. The short-axis focus in 1-dimensional transducers is fixed, which results in poor elevational resolution away from the focal zone. Using multiple foci improves lateral resolution but degrades temporal resolution. The sonographer can adjust the dynamic range to change contrast and bring out subtle masses. Contrast resolution is limited by processing speed, monitor resolution, and gray-scale perception of the human eye. Ultrasound is an evolving field. New technologies include miniaturization, spatial compound imaging, tissue harmonics, and multidimensional transducers. Clinical cytopathologists who understand ultrasound physics, instrumentation, and clinical ultrasound are ready for the challenges of cytopathologist-performed ultrasound-guided fine-needle aspiration and core-needle biopsy in the 21st century.
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Arch. Pathol. Lab. Med. · Oct 2010
Bronchioloalveolar carcinoma and the significance of invasion: predicting biologic behavior.
A resected adenocarcinoma illustrates challenges in diagnosing bronchioloalveolar carcinoma (BAC). Bronchioloalveolar carcinoma is defined by lack of invasion, something that may be difficult to assess in scars. ⋯ Larger areas of invasion are associated with a more aggressive course and more reliably distinguish BAC from other variants of adenocarcinoma. Separating BAC from other forms of adenocarcinoma is important owing to differences in prognosis and emerging therapeutic strategies.