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P S Cosgriff

Publications and source records attributed to P S Cosgriff.

10 recordsLinked to original sources

Transport dynamics of the hepato-biliary system: a mathematical model allied to Tc 99m IDA scintigraphy.

A generalised mathematical model of hepatic biliary tracer flows is formulated in terms of physiologically identifiable transport parameters. From a particular solution derived from this, the system response to intravenous administration of Tc99m IDA biliary tracer is predicted. Minimisation procedures applied to this solution combined with experimental scintigraphic observations yield estimates for the physiological parameters pertaining to a number of patient studies. Some hepatic conditions where quantitative indicators may contribute to clinical diagnosis are discussed.

Biliary Tract

Measurement of renal functional reserve of the single kidney in man.

The renal functional reserve capacity (RFRC) and response of the single kidney to a low protein diet (LPD) were investigated. Effective renal plasma flow (ERPF) and glomerular filtration rate (GFR) were measured using a single injection of I125 Hippuran and Cr51 EDTA during a dopamine infusion (3 micrograms/kg/min) and after 2 weeks on a LPD (0.6 g/kg/day). Dopamine increased ERPF but the associated rise in GFR was not significant. There was a significant decrease in both ERPF and GFR on LPD. The change in GFR during dopamine infusion, but not during LPD, correlated inversely with baseline GFR. Dopamine and LPD had no effect on heart rate or blood pressure and LPD did not alter urinary sodium excretion. These results suggest that the single kidney lacks functional reserve capacity and that protein restriction may be useful in preserving long term function.

Adult

The analytical sensitivity of Tc99m radionuclide 'milk' scanning in the detection of gastro-oesophageal reflux.

The analytical sensitivity of radionuclide 'milk' scans for detecting gastro-oesophageal reflux (GOR) has been assessed using an in vitro simulation test. Five factors were found to affect the ability to detect simulated reflux: isotope concentration, absolute gamma camera sensitivity, absorber thickness overlying the 'oesophagus' and volume and duration of reflux. We found that a critical volume-duration product must be exceeded for reflux to be detected. Radionuclide milk scanning appears to be much less sensitive in detecting transient events like GOR than might be expected from previously reported static simulation studies.

Child