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Biomedical subjects

J R Bloomer

Publications and source records attributed to J R Bloomer.

At least 91 records · Page 5Linked to original sources
PubMed1974

Canalicular bile secretion in man. Studies utilizing the biliary clearance of (14C)mannitol.

[(14)C]Mannitol was administered i.v. as a bolus injection to five postcholecystectomy patients with indwelling T-tubes and re-established enterohepatic circulations to evaluate the biliary clearance of [(14)C]mannitol as a means of estimating canalicular bile flow in man. [(14)C]Mannitol appeared in collections of bile 9-22.5 min after intravenous injection, rose to a peak, and thereafter paralleled the plasma [(14)C]mannitol disappearance curve. Bile-plasma [(14)C]mannitol ratios and [(14)C]mannitol clearances were determined during control and choleretic periods after correction of the bile [(14)C]mannitol points for the transit time of a given sample. After i.v. injection of sodium dehydrocholate in five studies, bile flow and mannitol clearance increased proportionately. However, when ductular secretion was stimulated with an i.v. bolus of secretin in three other studies, [(14)C]mannitol clearance remained essentially unchanged, indicating that [(14)C]mannitol entered bile at the level of the hepatocyte and could be utilized as a marker of canalicular flow in man. During control studies, when bile drained spontaneously from biliary fistulae in fasting patients, bileplasma [(14)C]mannitol ratios averaged 0.62+/-0.18 and canalicular flow, as estimated by [(14)C]mannitol clearance. (0.27+/-0.16 ml/min) accounted for 44-95% of total bile production (0.43+/-0.12 ml/min). When the rate of bile flow was plotted as a function of bile salt excretion after correction for the effects of biliary dead space, linear regression analysis revealed that approximately 7 mul of bile were secreted with each mumol of bile salt. Estimates of bile salt-independent canalicular flow accounted for at least one-third of the estimated 24-h bile production (604 ml) in these patients, indicating that this fraction of canalicular flow is a significant source of bile secretion in man.

Adult↗
PubMed1974

Variation in hepatic bile composition following cholecystectomy in patients with previous gallstones.

The composition of fasting hepatic bile was analyzed in 63 samples from 8 patients following cholecystectomy to determine if bile was lithogenic in patients with previous cholesterol gallstones after removal of the gallbladder. Bile specimens were obtained from t-tubes over a 7-20 day study period following re-establishment of the enterohepatic circulation. Bile composition varied on a day to day basis in each patient. 18 of 63 samples were lithogenic according to criteria of Admirand and Small while 35 of 63 samples were lithogenic according to criteria of Hegardt and Dam. Variations in the composition of hepatic bile appeared related to changes in the excretion rate of bile acids. These studies demonstrate that hepatic bile may be lithogenic after cholecystectomy and indicate that factors other than sequestration of the bile acid pool in the gallbladder influence the enterohepatic circulation of bile acids and the lithogenicity of bile.

Adult↗
PubMed1972

Quantitative studies of the delivery of hepatic-synthesized bilirubin to plasma utilizing -aminolevulinic acid-4- 14 C and bilirubin- 3 H in man.

After the simultaneous intravenous administration of unconjugated bilirubin-(3)H and delta-aminolevulinic acid-4-(14)C, the plasma disappearance curves of unconjugated bilirubin-(3)H and the plasma appearance curves of biosynthesized unconjugated bilirubin-(14)C have been defined in seven patients, three of whom had acute intermittent porphyria (AIP). The incorporation of (14)C into plasma unconjugated bilirubin, derived by an analysis which involves deconvolution of the two plasma curves, varied between 13.1 and 23.5% (mean 19.3%) of the injected dose in the nonporphyric patients and between 5.4 and 13.6% (mean 8.3%) of the injected dose in the porphyric patients. In five of the patients, the stercobilin-(14)C specific activity in a pooled specimen of feces was measured, enabling the following further values to be calculated: (a) the total (14)C radioactivity incorporated into bilirubin (21.0 and 25.3% [mean 23.2%] of the injected dose in two of the nonporphyric patients and between 8.5 and 25.3% [mean 14.2%] of the injected dose in the porphyric patients), and (b) the proportion of hepatic synthesized bilirubin delivered directly to plasma in the unconjugated form (between 0.520 and 0.904; mean for nonporphyric patients 0.712; mean for porphyric patients 0.614). The results demonstrate that a large proportion of bilirubin derived from hepatic hemes passes through the plasma in the unconjugated form before conjugation and secretion into bile.

Adult↗
PubMed1971

The measurement of the synthetic rate of bilirubin from hepatic hemes in patients with acute intermittent porphyria.

A new method for the direct measurement in vivo of the synthetic rate of bilirubin from hepatic hemes is proposed. This method depends on the application of the labeled precursor-product relationship to the hepatic pool of porphobilinogen, which is a common precursor of both urinary porphobilinogen and hepatic-synthesized bilirubin. The hepatic pool of porphobilinogen is labeled by means of an intravenous injection of delta-aminolevulinic acid-4-(14)C. The proportion of total bilirubin production which is derived from hepatic hemes is calculated from the ratio of the mean (14)C specific activities of stercobilin and porphobilinogen estimated in pooled specimens of feces and urine, respectively. The method can be most readily applied to patients with acute intermittent porphyria, as the appreciable quantities of prophobilinogen in the urine of these patients greatly facilitate the measurement of porphobilinogen-(14)C specific activity. In three patients with acute intermittent porphyria, values obtained for the synthetic rate of bilirubin from hepatic hemes were 20.7, 15.8, and 13.3% of total bilirubin production.

Acute Disease↗