China
Africa
Explore chapters and articles related to this topic
DRCOG MCQs for Circuit B Questions
Published in Una F. Coales, DRCOG: Practice MCQs and OSCEs: How to Pass First Time three Complete MCQ Practice Exams (180 MCQs) Three Complete OSCE Practice Papers (60 Questions) Detailed Answers and Tips, 2020
Cervical erosion:Cause of intermenstrual bleeding.Covered by squamous epithelium.May be treated by cryosurgery.Commonly occurs in pregnancy.May be diagnosed by cervical cytology.
The Many Faces of Neoplasia
Published in Jeremy R. Jass, Understanding Pathology, 2020
Squamous cell carcinomas may also occur in areas where squamous epithelium is not found under normal circumstances. Lung cancers arising from the bronchial tree may be squamous, yet bronchi are lined by a specialised columnar type of epithelium or respiratory epithelium. The cells have whip-like cilia at their apex which are similar in structure to the tail of a sperm. These are only just visible under the microscope. Their wave-like coordinated motion wafts inhaled particles out of the lungs and up into the throat. The particles are trapped within mucus secreted by a second class of columnar cell called a goblet cell. In smokers and individuals with chronic lung disease this respiratory epithelium may be replaced by a squamous epithelium, a process described as metaplasia (Greek for ‘moulding a different form’). A diagnosis of squamous cell carcinoma of the lung may be suspected macroscopically because of the yellow colour of accumulated keratin. Squamous cell carcinomas are graded histologically (well, moderate and poor) on the basis of differentiation towards keratin production.
Neoplasia
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
These are tumours showing squamous differentiation (Figure 6.7) in the form of keratin production or the presence of intercellular bridges, which on electron microscopy can be seen to be desmosomes. Squamous carcinomas can arise from pre-existing squamous epithelium, e.g. of skin or larynx, but some, e.g. of bronchus and the cervical transformation zone, arise at sites where there is normally glandular epithelium, but squamous metaplasia has been followed by malignant change. Squamous carcinomas resemble normal squamous epithelium to a varying extent. Well-differentiated tumours show maturation from proliferating basal cells, through acanthotic cells resembling the stratum spinosum, to heavily keratinized cells. Poorly differentiated tumours show much less maturation, often with no keratin production, but consist of sheets of cells joined by intercellular bridges.
Breakthrough COVID-19 infection inducing acute epiglottitis in an immunized host
Published in Baylor University Medical Center Proceedings, 2022
Matthew Mitchell, Madison Buras, Mollie Shutter, J. Scott Wieters
COVID-19 is a disease manifestation of SARS-CoV-2 that presents with pharyngodynia, cough, nasal congestion, rhinorrhea, ageusia, and anosmia.1–3 SARS-CoV-2 is known to bind the angiotensin-converting-enzyme-2 (ACE2) receptor on respiratory epithelium. Notably, areas subject to high abrasion, such as the lingual and laryngeal epiglottic surfaces, are covered in squamous epithelium rather than respiratory epithelium and therefore have a significantly lower density of ACE2 receptors.1,4 This suggests why COVID-19–associated inflammation of the epiglottis is an uncommon presentation. However, studies have explored how differential expression of ACE2 receptors among individuals could explain the varying degree of COVID-19 outcomes.5 Rather than a true infectious epiglottitis, COVID-19–induced ACE2 inhibition of the potential space between the lingual surface epithelium of the epiglottis and its underlying cartilage may cause bradykinin-associated angioedema that mimics epiglottitis similar to the side effects of ACE2 inhibitors.3,6,7
The challenges of drug delivery to the esophagus and how to overcome them
Published in Expert Opinion on Drug Delivery, 2022
Julius Krause, Friederike Brokmann, Christoph Rosenbaum, Werner Weitschies
As already mentioned, the incidences of EoE, GERD and EAC are rising over the past decades. Thus, it is hardly surprising that the interest in treating these medical conditions is also increasing. Patients have to deal with various symptoms e.g. dysphagia which has an impact on quality of life and the level of suffering increases as a result [51]. EoE, GERD and EAC have in common the impairment of esophageal function, whether by affecting motor function or by damaging the integrity of the esophageal wall. The mucosa in healthy esophagus has different protective mechanisms against noxious factors in refluxate e.g. bile acids, gastric juice and different digestive enzymes [52,53]. As described above the mucosa consists of squamous epithelium which is covered with a thin liquid film produced from small glands in the submucosa. This mucus layer is the pre-epithelial defense against refluxate [54–56]. The mucus layer is inhomogeneous due to gravity and small amounts of liquid which are secreted [21] and is not as robust as the gastric mucus layer [57]. When gastric content is present in the esophagus for a prolonged time, the pre-epithelial defense malfunctions. This first protective mechanism is followed by the epithelia defense. It is based on tight junctions, adherens junctions and desmosomes [57]. The last protective mechanism of the esophageal mucosa is the post-epithelial defense, more precisely the blood supply [58]. When these three defense mechanisms fail, cell remodeling and inflammation occur [57].
Therapeutic role of Azadirachta indica leaves ethanolic extract against diabetic nephropathy in rats neonatally induced by streptozotocin
Published in Ultrastructural Pathology, 2021
Abd El-Fattah B. M. El-Beltagy, Amira M.B. Saleh, Amany Attaallah , Reham A. Gahnem
In control and neem supplemented groups, the renal corpuscle appeared with normal ultrastructure architecture whereas it consisted of the glomerulus and Bowman’s capsule. The glomerulus consisted of tufts of blood capillaries that lined with capillary endothelium. The endothelial cells lining the capillary lumen are characterized by their protruding nuclei inside the glomerular basal lamina (BL) without clearly visible cytoplasm and regularly perforated with fenestrations. Also, the capillary loops are supported by little and irregular mesangial cells which characterized by their electron dense cytoplasm. Bowman’s capsule consisted of outer parietal layer and inner visceral layer. The parietal layer represented by a single layer of flattened squamous epithelium with centrally located nuclei. The visceral layer composed of podocytes, from which arise several primary processes or pedicles. Each primary process gives rise secondary processes. The latter processes were in direct contact with the BL of the glomerular capillaries. The filtration slits between secondary processes of podocytes appeared with regular diameter (Figure 3A&B).