Lymph node burden

Fig. 2a. Pulmonary and lymph node burdens of inhaled radioactive particles for Class W and Class Y compounds (no radioactive decay) as projected from the TGLD clearance model.

The increase in lymph node burden seen with ultrafine titanium dioxide has also been cited as evidence of increased interstitial transport of small particles (49,91). The problem with this line of reasoning is that, although, in one sense, it is true by definition, increased lymph node burdens tell nothing of the route by which the particles reached the lymph nodes certainly lymph node burdens provide no direct information about epithelial uptake and transport. 

An orthotopic model of mCRC with a high rate of metastasis to the para-aortic lymph nodes has been developed utilizing implantation of tumor cells into the submucosal layer of the rectum (11, 12). In these models, primary tumor burden is evaluated by measuring tumor volume with a caliper, while lymph node metastasis is evaluated histologically. 

Dabbs DJ, Fung M, Landsittel D, et al. Sentinel lymph node micrometastasis as a predictor of axillary tumor burden. Breast /. 2004 10 101-105. 

Intake of lead via inhalation is dependent on atmospheric concentration, peu ticulate size and solubility in tissue fluids. Approximately 30% of inhaled lead is retained by the lungs, and clearance from the lungs occurs when the inhaled material is sequestered by alveolar cells or removed via the lymphatic vessels to local lymph nodes. Some inhaled material (about 5%) is absorbed by the mucosa and passes to the gastro-intestinal tract. In general, however it is thought that the contribution of inhaled lead to body burdens is relatively small (Lawther, 1972). 

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