Skull.Base.Surgery.of.the.Posterior.Fossa.[taliem.ir]

Skull Base Surgery of the Posterior Fossa

The posterior fossa is the most complex and surgically challenging region of human anatomy. The high density of eloquent neurovascular structures in this region necessitates a wide variety of surgical approaches. Because small surgical errors here have the potential to cause signifcant morbidity, the posterior fossa surgeon must become an expert in this anatomy. The images used in this chapter were created in Dr. Al Rhoton Jr.’s laboratory with the express purpose of making surgery in the posterior fossa more “accurate, gentle, and safe.” For more in-depth study, please refer to his textbook or the online Rhoton Collection . We will frst examine the enclosure of the posterior fossa which is formed by the bowl-shaped skull base covered by the pitched tentorium. We will then review Dr. Rhoton’s “rule of three,” which divides the neurovascular contents of the posterior fossa into three groups of structures, each organized around a major posterior fossa artery. The cranial nerves, arachnoid cisterns, and special regions of the posterior fossa are then surveyed from the perspective of various surgical approaches.
Senescence.Physiology.or.Pathology.[taliem.ir]

Introductory Chapter: Molecular Basis of Senescence

In humans, the threshold of normal aging is accepted to involve the age of 60 years. At the same time, the age above the normal aging was divided into three subgroups, including young olds (65–75 years of age), old olds (75–85 years), and eldest olds (above 85 years of age) . Normal aging is defned as weakening of the repair and defense processes of the body. The weakening of the defense in aging organism leads to increase in the level of toxic factors such as reactive oxygen species (ROS), calcium ions, and immuneinflammatory response. The consequence of the change in the level of these molecular factors is the development of age- related diseases, among others, atherosclerosis, tumors and neurodegenerative diseases. Simultaneously, ROS may lead to the damage of macromolecular compounds, such as lipids, proteins, and DNA . ROS may also play an important role in the modulation of transcription factors activation, gene expression, and various life processes of a cell.
Immunopathology.in.Toxicology.and.Drug.[taliem.ir]

Molecular and Integrative Toxicology

The thymus is a primary lymphoid organ where developing T cells (thymocytes) proliferate and differentiate before entering the systemic circulation to populate secondary lymphoid tissues and form the functional T cell repertoire. The thymus tightly controls the antigen specificity of these naive T cells in order to limit reaction with self antigens. In keeping with the importance of T cells to the health of the animal, their development and function are subject to many overlapping pathways and checkpoints. Therefore, many of the key players involved in T lymphocyte development, differentiation and function are potential targets for pharmaceutical intervention in aberrant T cell immune responses resulting in disease. This chapter outlines the complex function of the thymus, the range of changes seen as part of normal physiological and disease processes, and its response to immunotoxicants.
Radiation.Oncology.for.Pediatric.CNS.[taliem.ir]

Radiation Oncology for Pediatric CNS Tumors

Childhood brain tumors are the most common form of pediatric solid tumors. Signifcant improvements over the decades in the treatment of brain tumors in children have improved outcomes but mortality and morbidity are still high. Pediatric brain tumors are clinically and biologically distinct from those that occur in adults. Our understanding of risk factors in childhood brain tumors remains limited to several exposures of the head and neck to ionizing radiation and well-described hereditary cancer predisposition syndromes. In this chapter ,we review the descriptive and analytic epidemiology of childhood brain tumors, including a discussion of the roles of radiation exposure, established predisposing syndromes, and other suspected risk factors.
Rotator.Cuff.Injuries.A.Clinical.Casebook.[taliem.ir]

Rotator Cuff Injuries A Clinical Casebook

Rotator cuff tendonitis is one of the most commonly encountered shoulder pathologies, with lifetime prevalence up to 67% . Also known as rotator cuff tendinopathy or “shoulder impingement syndrome (SIS),” this spectrum of disorders includes a variety of conditions such as subacromial bursitis, rotator cuff inflammation or partial tears, acromioclavicular (AC) joint pathology, and long head of the biceps tendinosis. These conditions may originate from extrinsic causes, intrinsic causes, or a combination of both. The final common pathway is a painful shoulder that limits movement and interferes with activities of daily living. Subacromial impingement, as described by Neer, involves the supraspinatus outlet, acromion, coracoacromial ligament, and AC joint . Extrinsic causes of rotator cuff tendonitis include anatomical variants of the acromion, thickening of the coracoacromial ligament, or subacromial bursitis. Direct compression of the rotator cuff tendons and surrounding tissues is thought to lead to the development of rotator cuff tendonitis, degeneration, and ruptures. Conversely, intrinsic causes develop with degeneration of the rotator cuff tendons themselves. This degenerative process may have a genetic component and is exacerbated by age, vascular supply, or a history of trauma. Patients usually report shoulder pain at rest, particularly nighttime pain, or pain with overhead activity. Plain radiographs may show an os acromiale, AC degenerative changes of the AC joint or glenohumeral joint, calcium deposits, or cystic changes of the greater tuberosity. Advanced imaging such as MRI may help further delineate the extent of damage to the rotator cuff and surrounding soft tissues.
Bethesda.System.for.Reporting.Thyroid.Cytopathology.[taliem.ir]

The Bethesda System for Reporting Thyroid Cytopathology

In order to provide useful diagnostic information for clinical management, a fneneedle aspiration (FNA) sample of a thyroid nodule should be representative of the underlying lesion. Real-time ultrasound guidance for thyroid FNA is recommended to confrm needle placement in the nodule. It is worth emphasizing that cellularity /adequacy is dependent not only on the technique of the aspirator but also on the inherent nature of the lesion (e.g., solid vs. cystic). High-quality specimens require profcient collection combined with excellent slide preparation, processing, and staining. In general, the adequacy of a thyroid FNA is defned by both the quantity and quality of the cellular and colloid components. Historically, the terms “nondiagnostic” and “inadequate/unsatisfactory” have been used interchangeably by many but not all pathologists: some have interpreted the terms to mean different things . An unsatisfactory specimen is always nondiagnostic, but some technically satisfactory specimens may also be considered “nondiagnostic,” that is, showing nonspecifc features not conclusively representative of a particular entity. At the 2007 NCI Thyroid State of the Science conference, the terms “nondiagnostic (ND)” and “unsatisfactory (UNS)” were equated and recommended for the category that conveys an inadequate/insuffcient sample . In this application, these terms are synonymous, and the laboratory should choose the one it prefers and use it exclusively for this category. The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) is a flexible framework, however, and can be modifed by the laboratory to suit the needs of its providers.
Atlas.of.Coronary.Intravascular.Optical.[taliem.ir]

Atlas of Coronary Intravascular Optical Coherence Tomography

Optical coherence tomography (OCT) uses near-infrared light to generate high-resolution images of coronary arteries in vivo and can be considered an optical analog of intravascular ultrasound, which uses light instead of sound. The near-infrared light with a wavelength of about 1.3 μm is invisible to the human eye. OCT uses low-coherence interferometry by measuring the echo time delay and intensity of the light reflected from internal structures in tissue to generate cross-sectional images. The light beam from an OCT system is split by an interferometer into two arms, a sample arm and a reference arm. The sample arm light travels to the sample tissue, then is being reflected, refracted, or absorbed by the tissue and fnally travels back to the interferometer. The reference arm is directed to a mirror, which reflects it back to the interferometer, combined with the sample arm light and detected by a detector. The OCT image is built based on the interaction between these two light waves, depending on whether there is constructive or destructive interference between the waves . Cross-sectional images are generated by measuring the delay time and intensity of light reflected or backscattered from internal structures in biologic tissue .
Advances.in.Endoscopy.in.Inflammatory.[taliem.ir]

Advances in Endoscopy in Inflammatory Bowel Disease

Endoscopic assessment of mucosal lesions has emerged as an important concept of disease activity in inflammatory bowel disease (IBD), and recently mucosal healing has generally been regarded as a therapeutic goal not only in ulcerative colitis (UC) but also in Crohn’s disease (CD). Several pieces of evidence have now accumulated to show that mucosal healing determined by endoscopy can alter the course of IBD, as it is associated with sustained clinical remission, and reduced rates of hospitalization and surgical resection. Generally, clinical activity indices established in IBD are mainly determined based on subjective/objective signs and the results of laboratory tests. However, those indices sometimes lead to discrepancy compared with endoscopic indices. Although endoscopy has been rarely investigated as a predictor of the clinical course of IBD, there is now growing evidence that morphological examination, including endoscopy, may help to identify among IBD patients those who should be treated with more intensive treatments. Furthermore, as demonstrated in a recent study assessing early intervention with combination of biologics and immunomodulators, endoscopy may help to select patients who will obtain the best results with early intervention. This chapter summarizes the role of endoscopy in IBD by introducing several modalities such as colonoscopy, balloon-assisted enteroscopy, and video capsule endoscopy, as well as CT colonography and MR enterography.
Leukaemia.Diagnosis.5th.edition.[taliem.ir]

Leukaemia Diagnosis

Leukaemia is a disease resulting from the neoplastic proliferation of haemopoietic or lymphoid cells. It results from mutation of a single stem cell, the progeny of which form a clone of leukaemic cells. Usually there is a series of genetic alterations rather than a single event. Genetic events contributing to malignant transformation include inappropriate expression of oncogenes and loss of function of tumour suppressor genes. Oncogenes may be either normal cellular genes (proto‐oncogenes) that have mutated or are dysregulated, or novel hybrid genes resulting from fusion of parts of two genes. The cell in which the leukaemic transformation occurs may be a lymphoid precursor, a myeloid precursor or a pluripotent haemopoietic stem cell capable of differentiating into both myeloid and lymphoid cells. Myeloid leukaemias can arise in a lineage‐restricted cell, in a multipotent stem cell capable of differentiating into cells of erythroid, granulocytic, monocytic and megakaryocytic lineages, or in a pluripotent lymphoid‐ myeloid stem cell. ymphoid leukaemias usually arise in a B‐ or T‐lineage stem cell but occasionally acute lymphoblastic leukaemia (ALL, either B‐ALL or T‐ALL) arises in a lymphoid‐myeloid stem cell, as shown by development of histiocytic sarcoma with the same clonal origin as the preceding B‐ or T‐lineage ALL .
Diet.Nutrition.and.Fetal.Programming.[taliem.ir]

Diet, Nutrition, and Fetal Programming

As evidenced by the current volume, there is a large and rapidly growing literature indicating that certain exposures in the prenatal period may have lasting effects on the behavior and biology of the child. Prenatal diet and nutrition is a particular focus of this volume. We seek to build upon and connect that literature to an equally large, but thus far largely separate, line of research suggesting that prenatal stress can also alter fetal and infant health and development in a manner consistent with a fetal programming hypothesis. To date, surprisingly little research has explored the relationship between prenatal nutrition and stress in the context of infant development , however several lines of evidence suggest that this is an important future direction. First, maternal stress and poor nutrition often occur together. This overlap is most clearly illustrated in extreme cases such as the Dutch Hunger Winter of 1944–1945. The famine, which occurred due to military blockades during World War II, has been well-described, and individuals who gestated during that period have been followed for many decades to understand the long-term effects on their physiology (as well as that of subsequent generations) . Gestational exposure to the Dutch famine has been linked to psychological and metabolic changes in the offspring later in life. Similar fndings have been reported in studies of those who gestated during the Great Leap Forward Famine in China (1959–1961).