Chronically reserpinized rat as a model for cystic fibrosis: Na+ transport inhibitory effect in submaxillary saliva.

The retrograde perfusion assay in the rat parotid gland was used to investigate the effects of salivary secretions from control and reserpine-treated rats on Na+ reabsorption. Results demonstrated that submaxillary saliva from the treated animals caused a 69% inhibition of Na+ reabsorption, accompanied by a 28% reduction in the volume of saliva secreted, and a 22% reduction in flow rate. By contrast, submaxillary saliva from control rats caused a 6% inhibition of Na+ reabsorption, a 6% reduction in volume, and a 5% reduction in flow rate. Parotid saliva from reserpine-treated rats also inhibited Na+ reabsorption to the extent of 39% and caused a 38% reduction in volume and a 33% reduction in flow. Parotid saliva from control rats only inhibited Na+ reabsorption to the extent of 2.7% and caused a 4--6% reduction in salivary volumes and flow rates. The inhibition of Na+ reabsorption and the reduction in salivary volume and flow rates caused by submaxillary saliva of reserpine-treated rats were either abolished or significantly reduced when the saliva was previously heated to 100 degrees C, frozen, and then thawed or kept in glass tubes at 4 degrees C for 24 hr. These results indicate that saliva from reserpine-treated rats have comparable effects in this assay system to those of saliva from cystic fibrosis (CF) patients and further support its use as an animal model for this disease.

Duplex and color Doppler ultrasound in the differential diagnosis of choroidal tumors.

There is paucity of data on the value of neovascular blood flow measurements in the differential diagnosis of human choroidal tumors, mainly due to difficulties in quantitating tumor vascularity in vivo. Color Doppler imaging and Duplex ultrasound, the combination of B-mode ultrasound and pulse Doppler analysis, were used to quantify tumor blood flow in 103 untreated tumors of the choroid. Pulsatile blood flow was detected at the tumor base of 62 choroidal melanomas (tumor height (TH) 3.1-11.7 mm) with a mean peak systolic frequency (MPSF) of 0.98 kHz (range 0.3-2.7 kHz). Compared to melanomas pulsatile neovascular flow in choroidal metastases (TH 2.1-6.5 mm, n = 12) was significantly higher (MPSF 1.87 kHz, range 0.8-3.5 kHz). No Doppler signals were elicited from age-related macular degeneration (n = 9), choroidal nevus (TH 1.5-2.1 mm, n = 18) and choroidal osteoma (n = 2). The results indicate that the quantitative measurement of tumor blood flow by duplex and color Doppler ultrasound may serve as a new diagnostic tool in the evaluation of intraocular tumors.