Class: BE209
Group: W7
Members: Jarish Cohen, Thanh Tran Nguyen Duc, Victor Gaur, Timur
Kocaoglu, Marla Stump, Cathy Witczak
Date: December, 2002
Introduction:
Many conditions and diseases including dehydration and sickle cell anemia currently afflict millions of people living in third world countries and are going undiagnosed and untreated. Our experiment focuses on sickle cell anemia and dehydration because they are easy to diagnose and once diagnosed are relatively easy to treat. Sickle cell anemia, one of the most common human autosomal recessive disorders, is a blood disorder caused by an abnormal type of hemoglobin called hemoglobin S (HbS). In this disease, HbS clusters together and induces a change in the shape of red blood cells. These “sickled” blood cells can easily become trapped in small blood vessels, causing pain and more importantly preventing blood flow to significant organs. Once it is determined that a patient has the disease, there are therapeutic methods that can reduce the frequency, duration, and severity of symptoms and maintain an adequate supply of red blood cells to nourish the tissues. These methods include taking antibiotics and establishing a healthy diet that is high in folic and butyric acid.
This debilitating disease can be detected by taking a sample of a patient’s blood and measuring the concentration of hemoglobin. The concentrations of hemoglobin in the blood for a normal adult male and female are 13.6-17.7 g/dL (+/- 2g/dL) and 12.1-15.1 g/dL (+/- 2g/dL) (respectively), while the concentrations of hemoglobin for an adult male and female with sickle cell anemia are <13.5 g/dL (+/- 2g/dL) and <12 g/dL (+/- 2g/dL) (respectively). For a patient subjected to dehydration, it is expected that the concentration of hemoglobin will be higher than the normal range, because the lack of fluids in the body will cause the blood (and thus hemoglobin) to be more concentrated. The concentration of hemoglobin for individuals with dehydration is 17.8-19.0 g/dL and 15.2-16.2 g/dL for men and women respectively. The concentration of hemoglobin in the sample can be measured easily with a spectrophotometer. A spectrophotometer measures the absorption of transmitted photons by a solute. The values for absorption of an array of solutes of known concentration can be taken, and these values can be used to construct a calibration curve relating absorption to concentration of a known substance. Clinicians can use this relationship to determine a patient’s hemoglobin concentration and use this value in comparison with the relative hemoglobin concentrations caused by the aforementioned diseases to diagnose the patient.
However, testing for these diseases using a spectrophotometer is
not ideal. A standard spectrophotometer is costly, fragile, and not
very portable. In our experiment, we aim to create our own “field
spectrophotometer” that is portable, inexpensive, and accurate. These
qualities would make our device ideal to use in testing for these conditions
and diseases in third world countries, where resources that provide for
lab spectrophotometers are readily unavailable.