Dysfunction Information and Courses from MediaLab, Inc.

A platelet function assay (PFA) is a screening test for the evaluation of platelets/primary hemostasis. Common clinical applications include the following: Preoperative evaluation of platelet function Determining the presence of drug-induced platelet dysfunction Determining platelet functionality in high-risk pregnancy Evaluation of patients with suspected inherited or acquired platelet disorders such as von Willebrand disease Evaluation of a bleeding patientA PFA instrument is able to differentiate between drug-induced platelet defects and other platelet defects. PFA tests are superior to the bleeding time test. The bleeding time is often not reproducible and, in spite of attempts at standardization, remains prone to variations in test results between persons performing the test. It is also relatively insensitive to platelet function. The bleeding time cannot be used to identify patients who may have recently ingested aspirin or non-steroidal anti-inflammatory drugs or patients who may have a platelet defect attributable to these drugs. The bleeding time is used to assess platelet function, but may be affected by platelet quantity. NOTE: Aspirin, and some other drugs, may falsely prolong bleeding times. Patients must be asked about aspirin use, and be aspirin free for 7-10 days prior to testing, for valid results.

The amount of time needed for iron to increase to levels causing organ damage is variable and may be partially dependent on gender, dietary or other environmental factors, and unknown genetic factors. Blood loss through menstruation and pregnancy are thought to delay the onset of iron overload, and therefore symptoms of HH, in women. Similarly, regular blood donation may confer some degree of protection. The loss of hemoglobin within intact erythrocytes reduces the amount of iron available for recycling.As levels of storage iron increase, clinical features of iron overload, including hepatic dysfunction or failure, diabetes, hypogonadism, arthritis, cardiomyopathy, hyperpigmentation, and fatigue, may become evident.Symptomatic patients typically present in middle age between the ages of 30 and 60, although this is quite variable. Persons as young as 20 may show clinical signs and symptoms of HH.(6) In the US, males are more than twice as likely as females to be diagnosed with HH, and the majority of cases are found in Caucasians.

After the exposure, there is an incubation period that lasts between 45 and 180 days, with an average of 90 days.Many individuals with acute HBV will have no symptoms at all. Some will have a mild illness with loss of appetite, nausea and vomiting, and fatigue. About 30% of infected individuals will develop clinical hepatitis with jaundice (yellow discoloration of the skin and eyes due to liver dysfunction).

Albinism, one of the striking physical characteristics of Chediak-Higashi syndrome, is also thought to be related to the general dysfunction of cells. Albinism has been specifically related to the aggregation of melanosomes, the pigment producing cells in the body.