they possess binding sites specific to carbohydrates and have the capacity to interact with molecules of biological fluids and those present in cellular surfaces .
lectins can substitute natural linkers and activate cellular responses through different roads of intracellular signalling or endocytosis of formed compounds [ 3 , 4 ] .
camaratu or camaratuba bean ( cratylia mollis ) is forage of the northeast semi - arid region from brazil .
molecular forms of c. mollis seed lectin ( cramoll 1 , cramoll 2 , cramoll 3 , and cramoll 4 ) have been highly purified and characterized ( de souza et al . ,
cramoll 1 , cramoll 2 , and cramoll 4 specifically bind glucose / mannose , while cramoll 3 is a galactose - specific glycoprotein
. preparations containing isoforms ( cramoll 1,4 ) and isolectins ( cramoll 1,2,3 ) , as well as cramoll 1 , have been studied in structural analyses and for the most several biotechnological applications ( de souza et al . , 2003 ) [ 612 ] .   the use of nuclear technique for the evaluation of biomolecules and medicines although old is not widely used even nowadays . since the discovery of the element technetium , in 1947
scintigraphy imaging provides a dimensional method for exactly locating gamma emitters in a noninvasive procedure under in vivo conditions . for the characterization of drugs , and biomolecules , molecular imaging techniques are extremely helpful to follow biodistribution in experimental animal studies . in this study
, the isolectins cramol 1,4 were radiolabeled with tc-99 m for the evaluation of the biodistribution and in order to forecast a possible use as radiopharmaceutical in healing process .
the labeling processes were made using 150  l of cramol ( isoform 1,4 ) solution incubated with stannous chloride ( sncl2 ) solutions ( 80  l / ml ) ( sigma - aldrich ) for 20 minutes at room temperature .
then , this solution was incubated with 100  ci ( approximately 300  l ) of   technetium-99 m   ( ipen / cnen ) for other 10 minutes in order to label the cramol 1,4 ( here just called cramol ) with tc-99 m . in order to characterize the labeled cramol , thin - layer chromatography ( tlc ) was made using   paper whatman no .
the tlc was performed using 2  l of a labeled sample in acetone ( proquimios ) as a mobile phase .
the radioactivity of the strips was verified in a gamma counter ( packard , cobra ii ) as described in table 1 .
the institutional review board and the animal ethics committee approved the study protocol for this study . the labeled samples ( 3,7  mbq/0,2  ml )
planar images were obtained 1 hour after injection at a millennium gamma camera ( ge healthcare , cleveland , usa ) .
counts were acquired for 5  min in a 15% window centered at 140  kev ( figure 1 ) .
then , animals were sacrificed , their were organs removed and weighted , and the radioactivity uptake was counted in a gamma counter ( packard - cobra ii ) .
results were expressed as the percentage of injected dose per organ and percent of injected dose per gram of tissue ( table 2 , figures 2 and 3 ) .
, the results showed that the acetone can be used for this purpose . in a triplicate test ,
the free pertechnetate was eluted to the top of the chromatograms , and the cramol stayed in the bottom .
moreover , the results observed in the chromatogram elucidated the question about the efficacy of the labeling process , corroborating that the cramol was efficiently labeled with tc-99 m .
tc - cramol scintigraphy 1  h after injection shows liver , kidneys , and bladder .
as we can see , the great part of the lectin was processed by the liver .
this is absolutely normal especially for injectable drugs , since almost all the drugs are first processed by the hepatic system ( figure 2 ) . otherwise , when dissecting , weighting and counting   the organs , a suspicious data appeared .  
as a protein , we were expecting that its clearance would be made by the kidney , and in fact , it occurred .
however , the rate between the bowel and the kidney is over the double . in this case , the clearance time would be reduced and the reabsorption of the drug could be facilitated by the microvilli of the bowel . in this case  
a dosage error could occur or even a toxic reaction due its accumulation in the bowel .
in both cases ,   further studies should be made to clarify this mechanism   and the relevance of that information in a developed drug based on lectin similar to the cramol 1,4 .
it is interesting to notice , analyzing both figures 1 and 2 , that the lectin can not pass the hematoencephalic barrier . and in this case , the lectin does not represent a risk for the brain function .
the radiolabeling of the cramol showed that this lectin has an uncommon behavior specially related to the clearance mechanism that we believe must be more studied .
it also showed that the nuclear technique can be very helpful for the development of drugs and medicines .
 the cramoll 1,4 is a well - studied lectin . 
 however , few studies about its biodistribution have been done before . in this study , we radiolabeled   the cramol 1,4 with tc-99 m and analyzed the biodistribution . 
 the results showed that the cramol has an abnormal uptake by the bowel with reflections on its clearance mechanism . 
1. Introduction
2. Methods
3. Results and Discussion
4. Conclusion