Tumors blood flow rate

DiPette, D. J., Ward-Hartley, K. A., and Jain, R. K. (1986) Effect of glucose on systemic hemodynamics and blood flow rate in normal and tumor tissues in rats. Cancer Res. 46, 6299-6304. 

Studies in Patients. During the investigations in patients with brain tumors or brain lesions, mean regional cerebral blood flow in the perifocal edematous areas amounted to 20.6 ml/100 g-min. These values decreased significantly in comparison with the mean hemispheric blood flow rate obtained with the same method in normal patients (50-55 ml/100 g-min) (27). The largest reduction in rCBF was encountered in patients with metastatic tumors and glioblastomas and may be related to the well-known tendency of these malignancies to develop brain edema. 

Fig. 4.3. Variability of blood flow rates in solid tumors (see = squamous cell carcinomas, modified from Vaupel and Hockel 2000)...

Figure 6. Effect of a second-generation ACE inhibitor, temocapril, on tumor blood flow. Note the great difference in flow rate in normal organs (A) vs that in tumor (B). Tumor blood flow was most affected by elevating blood pressure. The tumor used was LY80 in rats. (Adapted fh)m ref. 39).

Fiber components are the principal energy source for colonic bacteria with a further contribution from digestive tract mucosal polysaccharides. Rate of fermentation varies with the chemical nature of the fiber components. Short-chain fatty acids generated by bacterial action are partiaUy absorbed through the colon waU and provide a supplementary energy source to the host. Therefore, dietary fiber is partiaUy caloric. The short-chain fatty acids also promote reabsorption of sodium and water from the colon and stimulate colonic blood flow and pancreatic secretions. Butyrate has added health benefits. Butyric acid is the preferred energy source for the colonocytes and has been shown to promote normal colonic epitheUal ceU differentiation. Butyric acid may inhibit colonic polyps and tumors. The relationships of intestinal microflora to health and disease have been reviewed (10). 

Inhaled anesthetics decrease the metabolic rate of the brain. Nevertheless, the more soluble volatile agents increase cerebral blood flow because they decrease cerebral vascular resistance. The increase in cerebral blood flow is clinically undesirable in patients who have increased intracranial pressure because of a brain tumor or head injury. Volatile anesthetic-induced increases in cerebral blood flow increase cerebral blood volume and further increase intracranial pressure. 

Corticosteroids are used in clinical practice to relieve pressure symptoms caused by many tumor types, notably intracerebral tumors but also those causing airway or central venous obstruction. Their mode of action has been studied in animals (57) and humans (58), and is thought to involve first constriction of tumor vascular volume and then a reduction in water content. Reduced interstitial pressure should increase perfusion and extravascular diffusion rates, and high doses of steroids have been shown to increase blood flow in human colonic tumors transplanted into mice. Uptake of antibody into tumors has been assessed before and after administration of high-dose dexamethasone to decrease tumor interstitial pressure and thus increase antigen accessibility. Three patients with recurrent colorectal carcinoma had two antibody scans each, 72 h apart, and the injected dose was the same for all scans (20 mg). Dexamethasone was started 24 h before the second dose of antibody, with an initial iv dose of 10 mg followed by 4 mg four times daily orally for 48 h. 

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