Environment Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Environment and links to relevant pages within the course.
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|Naturally occurring antibodies found in the ABO blood group system may be due to exposure to which of the following?||View Page|
|Cause and Effect Diagram and DOE|
Cause and Effect Diagram The cause and effect diagram is also referred to as the Ishikawa diagram (created by Kaoru Ishikawa) or the fishbone diagram. In the cause and effect diagram, the problem or effect is stated on the head and the 5M (men (people), machine, material, measurements and methods) along with environment become the bones of the diagram. The team would brainstorm a list of possible causes for the problem and placed the causes in one of the six categories. The cause and effect diagram can assist the team in identifying areas that are contributing to the problem in a structured manner.Design of Experiments (DOE)One way to determine whether something is the root cause that is affecting a process would be to test it out in an experiment. For example if the team believes centrifuging stat and routine samples together contributes to the problem of increased turnaround time (TAT), then the team could design an experiment to test this out. Centrifuges could be designated as "stat centrifuges" and the TAT with and without the use of dedicated stat centrifuges could be compared. Keep in mind that just like in a scientific experiments, other factors must be controlled to validate the finding of the experiment. While DOE is a good way to verify root cause, it can be impractical or costly to setup.
Podschun R. Ullmann U.: Klebsiella spp. as nosocomial pathogens: epidemiology, taxonomy, typing methods, and pathogenicity factors Clinical Microbiology Reviews. 11(4):589-603, 1998 Bacteria belonging to the genus Klebsiella frequently cause human nosocomial infections. In particular, the medically most important Klebsiella species, Klebsiella pneumoniae, accounts for a significant proportion of hospital-acquired urinary tract infections, pneumonia, septicemias, and soft tissue infections. The principal pathogenic reservoirs for transmission of Klebsiella are the gastrointestinal tract and the hands of hospital personnel. Because of their ability to spread rapidly in the hospital environment, these bacteria tend to cause nosocomial outbreaks. Hospital outbreaks of multidrug-resistant Klebsiella species, especially those in neonatal wards, are often caused by new types of strains, the so-called extended-spectrum-beta-lactamase (ESBL) producers The incidence of ESBL-producing strains among clinical Klebsiella isolates has been steadily increasing over the past years. The resulting limitations on the therapeutic options demand new measures for the management of Klebsiella hospital infections. While the different typing methods are useful epidemiological tools for infection control, recent findings about Klebsiella virulence factors have provided new insights into the pathogenic strategies of these bacteria. Klebsiella pathogenicity factors such as capsules or lipopolysaccharides are presently considered to be promising candidates for vaccination efforts that may serve as immunological infection control measures.
|The hands of hospital personnel represents one of the major reservoirs for the persistence and potential spread of extended-spectrum beta-lactamase (ESBL) producing strains of Klebsiella pneumoniae in the hospital environment.||View Page|
|True of false: one of the functions of CSF is to maintain a stable chemical environment.||View Page|
|Examining a Diluted Specimen|
Examining a diluted CSF specimen involves the following steps: Mix the CSF sample manually 6 - 10 times or place it on a mechanical mixer for 5 - 10 minutes. Use a calibrated automatic pipet and place the appropriate volume of sample and diluent in a tube. Mix the diluted sample well. Use a Pasteur pipet and fill both sides of the hemacytometer. Allow the cells to settle for 5 minutes in a moist environment. Count cells in the four corner squares and the center square on both sides of the chamber. The number of cells counted times the dilution factor is then equal to the number of cells per µL.
|Nitrite Test Sensitivity|
This test is sensitive to 0.06-0.1 mg/dL nitrite ion in urines with a low specific gravity and with ascorbic acid concentrations of less than 25 mg/dL. Pink spots or pink edges should not be interpreted as a positive result because some medications can color urine red or turn red in an acid environment. Any degree of uniform pink color should be considered positive, suggesting the presence of 105 organisms/mL. Detection of low levels of nitrite ion may be enhanced by comparing the activated test strip to a white background. It is important to note that color development is NOT proportional to the number of bacteria present. The test is specific for nitrites and does not react with any other substances normally present in urine. Negative results do not necessarily rule out a urinary tract infection with yeasts or gram-positive bacteria unable to reduce nitrites.
This test is sensitive to 0.06-0.1 mg/dL nitrite ion in urines with a low specific gravity and ascorbic acid concentrations of less than 25 mg/dL. Pink spots or pink edges should not be interpreted as a positive result because some medications can color urine red or turn red in an acid environment. Any degree of uniform pink color should be considered positive, suggesting the presence of 105 organisms/mL. Detection of low levels of nitrite ion may be enhanced by comparing the activated test strip to a white background. It is important to note that color development is NOT proportional to the number of bacteria present. The test is specific for nitrites and does not react with any other substances normally present in urine. Negative results do not necessarily rule out a urinary tract infection because yeasts or gram-positive bacteria unable to reduce nitrites may be the causative agent.
|Transport of Lipophilic Substances|
Many lipophilic substances, including fat-soluble vitamins, cholesterol, and triglycerides are essential for life. The body needs to be able to absorb and transport these substances. However, lipophilic substances are not water-soluble, and, since blood is aqueous, this presents a challenge. The body addresses this need by using 'carriers' which can bind or sequester lipophilic molecules to aqueous 'vehicles' and thus transport them through the aqueous environment of the blood. Small lipid-soluble hormone molecules like estrogen, testosterone or cortisone are carried through the blood by binding to carrier proteins. Cholesterol and triglycerides are carried through the body in small spherical particles which trap the lipophilic molecules in their centers. These particles have an outer shell that is polar on the surface so that the particles are soluble in the blood but they have a lipophilic core which can hold fat-soluble molecules.
Lipoproteins differ in size and density as well as in their content (what they tend to carry). They also can differ in their origination (where they are made). Another significant difference between lipoprotein molecules is the proteins they have on their surfaces. These proteins, known as apolipoproteins, are the major identifying characteristics of a lipoprotein. There are many different apolipoproteins and we are continually learning more about them. Apolipoproteins have multiple roles. One role is that these amphipathic (detergent-like) proteins increase the overall solubility of the lipid particle, helping it to dissolve in the aqueous environment of the blood. Apolipoproteins can also function as enzyme co-factors (receptor ligands) and facilitate the transfer of their lipid cargo to specific cells. Thus, the apoliproteins are the smart or working-end of the lipoprotein particle. The apolipoproteins dictate where the particles will dock and where they can bind, and in so doing the apolipoproteins regulate lipid metabolism in the body.
HbSS blood may contain reticulocytes with an abnormal presence of CD36 on their membranes, allowing platelets to form a bridge between these young sickle cells and endothelial cells in post-capillary venules. This initial slow down of blood flow creates an environment in which cells containing HbSS can easily form sickled cells.The rigid cells, which are formed as a result of the sickling process, can collect in and plug small blood vessels. This can then cause tissue damage and organ infarction. In addition, the polymerized hemoglobin is thought to disrupt the RBC membrane, exposing phosphatidylserine that can trigger hemostasis. Subsequently, white blood cells (WBCs) may adhere to endothelium in response to recruitment in the inflammatory process. This leads to further occlusion as neutrophils capture additional RBCs in the post-capillary venules.Contributing further to vaso-occlusion is the decreased level of L-arginine in patients with sickle cell disease. L-arginine is a substrate needed to produce nitric oxide (NO). NO has vasodilatory properties as well as anti-inflammatory and anti-platelet properties. Thus a decrease in NO may lead to increased cellular adherence to endothelium.
|In HbSS blood, an increased amount of which of the following surface antigens on young sickle cells (reticulocytes) may allow platelets to form a bridge between the reticulocytes and endothelial cells, ultimately leading to vaso-occlusion?||View Page|
|Spread of the Infection (3)|
As the envelope is being formed, the HIV leaves the cell. This stage is known as budding. The virus moves through the cell membrane, acquires an envelope, and exits into the extracellular environment. It is now ready to infect another cell.
|Why Biological Agents Would Not Be Chosen as WMDs|
They are not immediate. The delayed effect, for example, the long incubation period for some agents, may detract and limit their tactful usefulness as a political statement.They are hazardous to all who come in contact.There is the possibility that the biological agents could also affect the health of the aggressor forces.They are hard to control.The dependence of prevailing winds and other weather conditions such as temperature, sunlight, and desiccation may make it difficult to control distribution of the biological agent.Potential long term effects beyond the initial attack.The persistence of some agents such as spore-forming anthrax in the environment may make an area uninhabitable to aggressor forces for long periods.Results are unpredictable.Morbidity secondary to a biological attack is unpredictable since casualties will be related to the quantity and manner of exposure plus the preventive and treatment measures available.
The bone marrow is structured to provide a suitable environment for developing cells as well as mechanisms for delivering mature cells to the circulating blood. The bone marrow is also capable of increasing production in one or more cell lines when needed.
Ergonomics evaluates work performance, viewing human and environment as one unit. If the human does not operate smoothly and efficiently with the environment, optimal performance will not be achieved and injuries may result. Since the human form cannot be redesigned, the environment must be evaluated and altered if necessary to achieve the best fit for the human operator to perform the task involved.
|The scientific study of human response to work demand is referred to as which of the following?||View Page|
|Creating an Ergonomically Safe Work Environment|
Both the employer and the employee should share the responsibility for assessing and improving ergonomics in the laboratory. A three-step ergonomic program includes: Finding the hazard Determining what improvements / changes should be made Taking action to improve the workplaceEmployers should: Provide ergonomics education Provide ergonomically designed tools and equipment Allow frequent stretch breaks If possible, adjust work schedules to prevent employees from performing repetitious tasks for prolonged periods of time. As an employee, you should evaluate the ergonomic practices in your work area.Employees should: Understand the risk of injury Apply ergonomic principles to the performance of tasks Look for ergonomic hazards and improve the workplace whenever possible Recognize and report early signs of musculoskeletal disorders (MSDs)
|Culture of Secrecy|
People tend to look for someone to blame when medical mistakes occur. Victims and their loved ones find some satisfaction in blaming.
An environment of blame encourages a culture of secrecy about medical mistakes. Mandatory reporting laws have not overcome this secrecy, and they do not encourage efforts to find ways of avoiding errors.
Error reduction requires a commitment from the healthcare community to recognize and acknowledge that medical errors indicate systems problems, not people problems.
|Challenges to Existing Programs
Current error-prevention programs face many challenges:||View Page|
|American Society for Clinical Laboratory ScienceThe American Society for Clinical Laboratory Science, ASCLS, joins the leadership effort to prevent medical errors and increase patient safety.||View Page|
|Factors that Contribute to Medical Errors||View Page|
|Match type of media on the right with best description:||View Page|
A 2009 evaluation and comparison of a variety of commercially available toxin detection assays, glutamate dehydrogenase (GDH) assays, the cytotoxin assay, cytotoxigenic culture, and real time PCR for the C. difficile tcdB gene revealed that ALL methods demonstrated a relatively low positive predictive value, which compromised the utility of a single test for laboratory diagnosis of C. difficile. However, of all methods, PCR had the highest negative predictive value, and was considered the optimum rapid single test.Molecular methods for C. difficile are based on the detection of the tcd gene. With the application of real time methodology, results can be available within 2 to 3 hours. These methods are highly sensitive and demonstrate good sensitivity, in comparison to all methods with the exception of toxigenic culture. As the methodologies and instrumentation are developed and improved, they are increasingly adaptable to the environment of a busy clinical diagnostic setting. The BD GeneOhm™ and Meridian illumigene® assays are examples of currently available molecular assays for C. difficile.
|Treatment of CDI/CDAD|
The first step in treating patients with CDAD is to discontinue the causative agent wherever possible. The choice for initial antibiotic therapy depends on the severity of disease. Oral vancomycin or metronidazole remain the mainstays of therapy for C. difficile infection, with vancomycin reserved for patients with more severe disease and/or those who have not responded to metronidazole. Metronidazole is currently favored in guidelines from the CDC on the basis of cost and concern that oral vancomycin promotes colonization with vancomycin-resistant Enterococcus. Oral fluids (water and electrolytes) may be necessary to counteract fluid loss as a result of excessive diarrhea, which can quickly lead to dehydration. Patients with fulminant disease and toxic megacolon may require colectomy. Recurrence of C. difficile infection (CDI) is becoming an increasing problem. Most recurrences happen 7 - 14 days after completion of therapy, suggesting relapse rather than re-infection. If a patient develops a second episode of CDI following initial successful treatment, it is recommended that if possible, the same drug be used to treat the second episode. Contributing factors to recurrent CDI include: Continuing exposure to organisms either through re-infection (via contaminated environment or poor hand hygiene) or an endogenous source, such as C. difficile spores in GI tract. An inability to mount an adequate anti-Toxin A IgM and/or IgG antibody response (i.e., poor host immune response); a likely reason why CDI affects an increasingly elderly population. Unfortunately a vicious cycle can arise whereby the initial treatment prescribed, vancomycin or metronidazole, significally disrupts normal colonic flora reducing colonization resistance and leaving the patient vulnerable to the next recurrent episode.Other treatments including the use of probiotics or anion-exchange resins to absorb toxins, may work in some cases but none work in every case.The goal of all treatment is to reestablish normal colonic flora so as to control C. difficile (over)growth.
|C. difficile disease is more likely to occur when:||View Page|
|Match the name of each fungal species listed with its most likely corresponding morphologic features.||View Page|
|Each of the following dimorphic fungal infections have been observed in animals living in their natural environment except:||View Page|
|Environment Monitoring for Formaldehyde|
Environmental monitoring is used to help prevent employee overexposure to formaldehyde. It is performed annually in designated areas where formaldehyde is routinely used.
|Monitoring the Environment|
Environmental monitoring is used to prevent employee overexposure to formaldehyde.It is performed annually in designated areas where formaldehyde is routinely used.
Your laboratory is committed to providing you with a safe working environment.
It also expects you to do your part :
Be a responsible member of the laboratory team.
Use safe work practices.
|The infective stage for all of the intestinal amebae is the:||View Page|
|The trophozoite is the only morphologic form in the life cycle of:||View Page|
|Arrange the following life cycle phases of Diphyllobothrium latum in order beginning with human transmission:||View Page|
|Arrange the following phases of the Chilomastix life cycle beginning with human transmission:||View Page|
|Which of the following specimen types is/are suitable for the recovery of Entamoeba histolytica?||View Page|
|Arrange the major steps of the ethyl acetate concentration procedure in order of completion:||View Page|
|The non-feeding, infective stage of the ameba is known as a/an:||View Page|
|Arrange the basic steps in the intestinal ameba life cycle in order starting with transmission to a human host:||View Page|
|The only nematode egg that is characteristically flattened on one side is:||View Page|
|Label the morphologic structures on this parasite form:||View Page|
|Label the morphologic structures on this parasite form:||View Page|
|Label the morphologic structures on this parasite form:||View Page|
|This parasite measure 50 µm by 30 µm. Its common name is:||View Page|
Posted signs should alert you to patient allergies. Some patients may be allergic to latex gloves or tourniquets, or to iodine.Avoid using latex in case of allergy. Latex allergies are fairly common, and can be severe.
May health-care institutions have reduced the use of latex because of allergies, but complete elimination of latex in the hospital environment is difficult, since it is a component of many medical products.
|Integumentary system : function|
The function of the integumentary system is to:
Protect the underlying tissues from the external environment.
Help regulate body temperature.
Culture Characteristics: Slow growing and fastidious Growth of visible colonies on agar may require two to five days Growth is stimulated by CO2 Will grow initially on sheep's blood agar (SBA), but growth is poor or absent on subculture Prefers cystein-enriched media such as chocolate (CHOC), Thayer-Martin (TM), buffered charcoal-yeast extract (BCYE), and thioglycollate (THIO) Growth is slow in broth, so blood cultures should be held up to three weeks if F. tularensis is suspectedColony Morphology on SBA at 35oC: Can grow poorly or not at all on SBA Tiny, pin-point, translucent colonies after 18-24 hours Difficult to see individual colonies in growth that is less than 24 hours Gray-white, opaque colonies less than 1 mm after 48 hours No hemolysisColony Morphology on CHOC at 35oC: Pin-point, gray-white, opaque growth after 24 hours 1-2 mm, gray-white, smooth, shiny growth after 48 hours Individual colonies exhibit mature growth at 3 days in CO2 environment and have a greenish appearance
Because real-time PCR can amplify extremely small amounts of genetic material, it can be used to detect and identify minute numbers of microbes in a specimen or in the environment. It can even be used to detect DNA of microorganisms that are nonviable or difficult to grow in culture. Before PCR and other amplification methods, microbes had to be cultured in order to obtain enough genetic material to analyze. Thus, dead microorganisms were almost impossible to identify. Cloning for microbial DNA was the method generally used to garner genetic material from microbes that were hard to grow; this process can be extremely lengthy and time consuming. The use of PCR creates a fast and practical way to replicate microbial genetic material, whether alive or dead. PCR is also commonly used for microbial fingerprinting in outbreak investigations as a way to confirm transmission or find the outbreak source. One can look for repeats in the genetic sequences by amplifying random polymorphic DNA, yielding PCR products of various sizes. These products can then be run through an electrophoresis gel, creating a band pattern that is known as the DNA fingerprint. PCR can also be used to fingerprint an entire microbial community in lieu of a specific organism. A community fingerprint is created by amplifying a sequence that is found in all organisms of interest. Community fingerprints can be compared over time to identify stability and variations. PCR has an advantage over culture techniques due to the differences in growth requirements and growth time. With cultures, it is common to miss organisms and determine relative abundance and frequency.
|Burr Cells (Echinocytes)|
Echinocyte comes from the Greek word meaning "sea urchin," which relates to its shell-like appearance. Echinocytes, more commonly referred to as burr cells, are reversible, meaning that this alteration can be the result of the cell's environment, pH of the medium (including the glass slides on which blood smears are made), the metabolic state of the cell and the use of some chemical substances. Several echinocytes (burr cells) can be seen in the top image; three of them are indicated by the arrows. Notice that the projections are rounded and evenly spaced around the cell and the cells have central pallor. Acanthocytes, by contrast, have irregularly spaced thorn-like projections and little or no central pallor. Although burr cells may be associated with diseases, such as uremia or pyruvate kinase deficiency, crenated cells, that may be confused with true burr cells/echinocytes, are frequent artifacts. Crenated erythrocytes are most commonly caused by excess EDTA (underfilled collection tube), but may also be caused by slow drying, drying in a humid environment, or an alkaline pH from glass slides. When crenation is an artifact, most cells on the slide will exhibit this characteristic. True burr cells are less numerous. Corrective actions include making a new smear or re-collecting the sample, if possible. The bottom image contains crenated cells that were the result of an underfilled EDTA collection tube. These should not be reported.
The term, stomatocyte, is derived from the Greek term, stoma, meaning mouth. Stomatocytes have elongated or slit-like central pallors, which may be curved, giving the central pallor an appearance of a smiling mouth. The occasional stomatocyte seen in normal smears is the result of a slight pH change in the environment, similar to the in vitro changes that cause cells to assume the echinocyte shape. Two stomatocytes are indicated by arrows on this slide.
|Composition of Semen|
Semen is a substance produced by the male reproductive organs. It is composed of spermatozoa in a semi-viscous fluid. Structures within the male reproductive tract that are involved in the production of semen include: Testes and epididymisProstateSeminal vesiclesBulbourethral glandSemen is produced as a combination of secretions from the different regions of the male reproductive tract. Each fraction differs in chemical composition and function. The combination of these fractions during ejaculation results in the optimal environment for transporting sperm to the endocervical mucus in the female. Spermatozoa are produced in the testes. They mature in the epididymis. The testes also produce testosterone and inhibin.Fluid from the seminal vesicles accounts for approximately 70% of semen volume. The seminal vesicles are the source of fructose in semen. Fructose is used by the spermatozoa as an energy source.The prostate gland supplies about 20% of the volume of semen. Its fluids include acid phosphatase and proteolytic enzymes that lead to coagulation and subsequent liquefaction of semen. The prostate also contains most of the IgA found in semen.The bulbourethral gland produces mucoproteins that make up about 5% of the volume of semen.
|Become and Remain a Competent Professional|
Phlebotomy is a skill that needs to be perfected. Because phlebotomy is an invasive procedure, it is imperative that you become and remain proficient. Many people are apprehensive when getting their blood drawn. Your professionalism will greatly decrease their fears.Individuals who collect blood specimens should be assessed for competence by a qualified mentor before being allowed to perform procedures on patients and periodically thereafter. It is important to receive feedback from the instructor/mentor so that you are ensured your phlebotomy techniques are appropriate. Any remedial training needed should be provided by qualified instructors in a controlled environment--preferably a classroom and not in the presence of patients. Training and competency assessment should again occur whenever new equipment is introduced. Training and assessment records should be kept in your employee file.Ask for assistance when unsure about a collection. Be professional at all times. You are an important part of the health care team.
|Mentally and Physically Disabled Patients|
The phlebotomist may encounter a patient with special needs due to physical and/or mental limitations. In these situations, the phlebotomist should assess the needs of the patient and employ others to assist if necessary.For patients that do not understand you when you try to explain the procedure, the patient's caregiver can be asked to assist by helping explain the procedure to the patient in terms that the patient will understand. The patient's caregiver is someone who the patient trusts and someone who knows how the patient will react. The phlebotomist should be as non-threatening as possible when communicating with special needs patients.For a patient with physical disabilities, the phlebotomist should try to modify the environment to accommodate the patient's needs. This may include lowering or heightening the draw chair to accommodate patient height and/or size. If the drawing room environment does not sufficiently accommodate the patient's needs, the phlebotomist should seek out a more appropriate location within the facility, if available.
|Presentation and Prevalence|
Although the risk of acquiring transfusion transmitted viral infections is low due to donor testing, bacterial infections are still reported. Platelets are the most implicated product in bacterial contamination reports because they are stored at room temperature (20-24oC) and provide a favorable environment for bacterial growth. Sespis occurs in about 1 in 25,000 platelet transfusions. It may be fatal in about 1 in 60,000 transfusions. Bacteria can be present in other components as well, such as red blood cells (RBCs), cryoprecipitate, and plasma. Contamination in red cell components is rare with events occurring 1 in 250,000 transfusions. This low incidence is due to the refrigerated storage requirements for red cells at 1-6oC. Because plasma and cryoprecipitate are stored frozen, they are least likey to contain bacteria. Contamination usually occurs when these products are thawed in a water bath that contains bacteria. Reactions range from minimal or no symptoms to fatal septic shock and death. Severity of the reaction depends on the bacterial species involved, the concentration and growth rate of the organisms, and the recipient's immune status. Septic reactions can present with a fever of higher than 38.5oC, rigors, and hypotension that begin during the transfusion. Patients may also have nausea, vomiting, dyspnea, and diarrhea. Septic shock, oliguria, and disseminated intravascular coagulation (DIC) are also complications.
|Which type of blood component is most implicated in bacterial contamination?||View Page|