Squamous Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Squamous and links to relevant pages within the course.
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|False Positive and Negative Urine Leukocyte Esterase|
False Positives:A false positive result may occur in the presence of strong oxidizing agents in the collection container. In random urine specimens from women, a positive result for leukocyte esterase may be due to a source external to the urinary tract. Other urine sediment findings such as bacteria, squamous or renal epithelial cells, lymphocytes or red blood cells do not contain esterases, and would not produce a positive leukocyte esterase test. False Negatives:False negative results may occur in the presence of significant levels of protein or glucose and in urines with high specific gravity which can crenate the white blood cells, leaving them unable to release esterases. Some drugs such as Cephalexin (Kelfex®), Cephalothin Keflin®), Tetracycline, or high concentrations of oxalic acid may also cause falsely decrease leukocyte esterase test results.
|False Positive Leukocyte Esterase Test|
A false positive result may occur in the presence of strong oxidizing agents in the collection container. In random urine specimens from women, a positive result for leukocyte esterase may be due to a source external to the urinary tract. Other urine sediment findings such as bacteria, squamous or renal epithelial cells, lymphocytes or red blood cells do not contain esterases, and would not produce a positive leukocyte esterase test.
|The cells faintly seen between the arrows are consistent with:||View Page|
|The cell indicated by the arrow is a:||View Page|
|Which of the following cells when found upon microscopic examination of the urine
would be most indicative of kidney disease:||View Page|
|Which of the following cells when found upon microscopic examination of the urine would be most indicative of kidney disease:||View Page|
|HPV as a Sexually Transmitted Infection|
HPV viruses infect the skin that lines the lower genital tract and mouth; viral DNA replicates in the squamous epithelium. Condom use reduces the risk of transmitting HPV but does not completely prevent transmission. Since the virus infects skin cells, there can be transmission in unprotected skin-to-skin contact.Symptoms of HPV viral infection are rare; the majority of individuals infected are unaware that they have contracted HPV. Most infections spontaneously resolve within a few months without the formation of lesions.
|Carcinogenesis of Cervical Cancer|
HR-HPV type viral infections, if left untreated, can convert normal cervical lining to cervical intraepithelial neoplasia (CIN). With a good immune response, the hyperplasia regresses and no carcinoma develops. This regression ocassionally occurs with CIN 2, but rarely occurs with CIN 3. If the CIN does not regress, high-grade squamous intraepithelial lesions (HSIL) develop. HSIL may progress to invasive carcinoma, typically in older individuals.
|Pap Smear Images|
Normal Squamous Epithelial Cells Stained with Papanicolaou Stain Abnormal Squamous Epithelial Cells Stained with Papanicolaou Stain
|Molecular Detection of HPV in Cervical Cytology Specimens|
HPV molecular testing involves the detection of HPV viral DNA in cervical cells collected during a pelvic examination. Molecular testing is utilized for detecting high risk-HPV (HR- HPV) types. The testing can be performed as: Primary screening for HPV with or without a Pap test Follow-up on abnormal Pap smear cytology Triage of atypical squamous cells of undetermined significance (ASC-US) Pap smear results
|Determine the Quality of a Sputum Specimen|
Prior to culturing a sputum specimen, a Gram stain should be performed to evaluate the quality of the specimen. One of two criteria are currently used to determine if the specimen is contaminated with oral flora organisms, which would make the specimen unsuitable for culture. One criterion states that the sputum specimen should be rejected if 25 or more squamous epithelial cells/low power field (SQE/LPF) are observed. The second criterion recommends a cutoff of more than 10 SQE/LPF. In either case, a minimum of 20 LPFs should be observed. Review and follow your laboratory's criteria.The low power microscopic field on the right is representative of 20 microscopic fields that were reviewed on this Gram-stained preparation of sputum. This specimen would be considered unacceptable for culture. If the specimen is determined to be a sub-optimal specimen, the clinician should be contacted and a request should be made for a new specimen. It is important to communicate that culturing the specimen that was provided will not yield useful information about the possible pathogens from the lower respiratory tract. If the specimen is determined to be a good quality, lower respiratory tract specimen, continue to examine the slide under oil immersion (1000X) magnification for bacteria, yeast, and polymorphonuclear white blood cells (PMNs) and proceed with culturing the specimen.
|Determine the Quality of a Urine Specimen Submitted for Culture|
The presence of many squamous epithelial cells (SQEs) also indicates a poorly collected urine specimen. If many SQEs are noted upon microscopic examination, the specimen should be recollected. The patient must be instructed how to collect a midstream, clean catch specimen. A Gram stain of a fresh, midstream urine sample would provide information that could help the physician decide whether to prescribe an antibiotic and the choice of antibiotic based on gram-reaction of the bacteria. Examine a Gram-stained slide made from a drop of uncentrifuged urine under oil immersion (1000X) magnification. If more than one bacterial organism is observed per oil immersion field, it can be determined that the quantity of bacteria is >105 colony forming units (CFU) per mL, and the patient probably has a urinary tract infection (UTI). The Gram stain reaction would also be important. Most bacteria that cause UTIs are gram-negative Enterobacteriaceae. A Gram stain report in this case would be "gram-negative bacilli consistent with quantity >105 CFU/mL."
|A large number of which of these types of cells would indicate that a sputum specimen is sub-optimal and should not be used for culture?||View Page|
The Gram stain reaction and appearance can be used to identify most cellular material seen in a direct smear. Identification of cellular elements present in a direct clinical smear is important because most of these elements play an important role in the disease process. For example, the quality of a sputum sample can be assessed by determining the relative numbers of squamous epithelial cells and polymorphonuclear leukocytes (segmented neutrophils) present.
|Which of the following cells may be difficult to differentiate from segmented or band neutrophils when performing a microscopic urine sediment examination?||View Page|
|What is the identity of the cells that are indicated by the arrow in this image?||View Page|
|Squamous Epithelial Cell|
A structure which may be misidentified as a cast is a squamous epithelial cell rolled into a cigar shaped cylinder, shown in the image with a blue arrow. Unless the nucleus is plainly visible, this epithelial cell may be difficult to differentiate from a cast.
|Renal Epithelial Cells of Collecting Duct Origin|
Another form of renal epithelial cells originates in the collecting ducts and measures 12-20 microns. These are identified by their characteristic cuboidal shape and large usually slightly eccentric nucleus. Cuboidal cells are sometimes confused with neutrophils. Neutrophils, however, are slightly larger to nearly twice as large (20-35 microns) as cuboidal cells and have a segmented or band-shaped nucleus while cuboidal cells have a single round nucleus. This view under high power phase contrast shows two cuboidal cells (blue arrows) lying between squamous cells (yellow arrows.)
|Squamous Epithelial Cells|
The most common type of cell seen in the urine sediment is the epithelial cell. This slide shows squamous epithelial cells under low power brightfield microscopy (upper image) and a squamous epithelial cell under high power. The sediment in the lower image was stained with a supravital stain. The cells appear as large flattened cells with abundant cytoplasm and small round central nucleus. Although squamous epithelial cells have little clinical significance they must be differentiated from other cellular elements.
|Squamous Cells Under High Power|
Under high power magnification the cytoplasm appears granular and a small round nucleus may be apparent.
|Squamous Cells Under Phase Contrast|
Using phase-contrast and high power, the cytoplasm and nucleus appear much darker. Note the folded edge of the cytoplasm, which is characteristic of squamous cells. The long, thread-like structures are mucous strands.
|Epithelial Cell Groups|
Sometimes epithelial cells appear in groups rather than singly. This field shows a cluster of squamous epithelial cells.
|The different types of epithelial cells include: (Choose all that apply.)||View Page|