Free Blood Flow computation macros for Microsoft Excel
Triton Technology offers two families of MS Excel macro for volume blood flow computation when using Dye-TrakŪ or Dye-TrakŪ VII+ colored microspheres. These macros allow the user to automatically download data files directly from most commercially available spectrophotometers. This eliminates the laborious and potentially error-prone manual copying of the absorbance data into the spreadsheet. Once the absorbance data is downloaded and the tissue wet-weights for each tissue sample are entered into the spreadsheet, the software will automatically compute the volume blood flow (ml/min/gram) for each tissue sample.
Similar to the spill-over between isotope counts with radioactive microspheres, the colored microsphere exhibit some spill-over between colors. Spill-over means that most microsphere colors will add some absorbance at one or more of it's neighbors peak wavelengths. The Triton Excel software macros work with user supplied color standards for each experimental color to determine the spill-over matrix. The Triton blood flow software does a mathematical matrix inversion process to remove the spill-over components at each microsphere color wavelength using this a priori spill-over information . The result is the corrected absorbance values at each experimental color wavelength. In other words, the absorbance values which would have been read at each wavelength had there been no spill-over. This is the same process that is used to correct gamma counter data from radioactive microspheres.
There is a family of Excel macros for the original Dye-TrakŪ 5-color family and another family of macros for the Dye-TrakŪ VII+ 7-color family. Further, each of these families has two variants: One with Process Control provision and one without Process Control..
Process Control is discussed at length in the Dye-Trak Users Manual. Basically Process Control involves using a repeating pipette to add a known number of Blue microspheres to each sample processing tube (for both tissue and blood samples) prior to digesting and processing the sample to recover the microspheres. The expectation is that all the Blue microspheres will be recovered from each tissue and blood sample. If part of a sample is lost during processing, the percentage recovery of the Blue microspheres is a measure of processing efficiency and allows the software to 'back calculate' to correct all the AU readings at each wavelengths to account for the lost portion of that sample.
There is a separate macro for each number of microsphere colors used in at experiment. This is done to maximize the accuracy of the matrix inversion calculation. If you were to use the macro for six colors when you actually only used four colors and then you placed zeros for absorbance values for the two unused colors, the matrix inversion calculation output will be 'noiser' than if you use the macro for four experimental colors
Triton Technology strongly recommend the use of the Process Control. For a few pennies per sample, the accuracy of the data is improved and the loss of important data is minimized.
The first thing a new Blood Flow spreadsheet user should do is to download the Excel Macro Instructions in order to understand how to set-up and use the macros.
Link to original 5-color Dye-TrakŪ macro page.
Link to 7-color Dye-TrakŪ VII+ macro page.