The importance of arterial reconstruction in experimental orthotopic rat liver transplantation is widely acknowledged in the literature. Non-rearterialization of the graft leads to impaired microcirculation and, in chronic models, to severe hepatobiliary damage, together with bile duct proliferation and fibrosis in such livers. The aim of the current study was to investigate the impact of rearterialization on hepatic oxygen tension (pO2), hepatic tissue content of adenine nucleotides, early graft function, and postoperative outcome. Orthotopic liver transplantation was performed in 27 male inbred rats. Ten rats underwent rearterialization and while 17 did not. A group of sham-operated animals (n = 6) served as controls. After reperfusion, liver grafts without arterial reconstruction showed significantly reduced levels of oxygen tension (mean +/- SD, 3.79 +/- 2.20 vs. 10.03 +/- 2.84 mmHg; P < 0.05) and a clear shift toward lower pO2 values in the pO2 histograms, as compared with arterialized grafts. Without arterialization, the level of liver ATP was 65% of that in sham animals, compared with 84% in arterialized livers. Without arterialization, bile secretion was reduced (0.42 +/- 0.04 vs. 0.71 +/- 0.06 mg/min x g liver; (P < 0.001), and the postoperative course of serum alanine transaminase, bilirubin, and alkaline phosphatase revealed severe hepatobiliary damage. These findings allow us to conclude that graft rearterialization is essential to ensure both an adequate oxygen supply and maintenance of tissue ATP. Arterialization may thus be a necessary part of liver transplantation models in this animal species, and should be considered when designing studies on the biochemical, microcirculatory, and histopathological status of the graft.

A sensitive somatostatin radioimmunoassay was developed and immunoreactive somatostatin was measured in plasma of different vessels of stressed and non-stressed rats. Detection limit of the assay is 4 pg/ml. Serial dilutions of rat plasma run parallel to the standard curve. On gel chromatography of rat plasma immunoreactive somatostatin elutes at the position of synthetic somatostatin. Immunoreactive somatostatin in plasma of non-stressed rats is (mean +/- 1 SEM) 369 +/- 58, 244 +/- 66, 273 +/- 61, 260 +/- 44, 359 +/- 80 pg/ml in aorta abdominalis, vena cava, vena renalis, vena jugularis, vena porta respectively. After stress mean immunoreactive somatostatin was higher in plasma of all vessels, in aorta abdominalis (p less than 0.01), vena renalis and vena porta about 50 per cent, in vena jugularis and vena cava about 90 per cent (p less than 0.002). We conclude that under conditions like stress somatostatin circulates in increased amounts and perhaps reaches organs distant from documented sources.

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Stone analyses (kidney, upper urinary tract) of the department of Urology, University of Erlangen, from a four-year-period (1974-1977) have been recorded with emphasis to stone composition, sex and age of the pertinent stone forming patients. During this time period there were no substantial changes as regards the per cent frequency of the various stone types. The most frequent type was calcium oxalate (CaOx), followed by uric acid, calcium phosphate (CaP), struvite and cystine. Stone analyses were mostly requested for patients between 46 and 55 years of age. Stone incidence in our clinic is calculated to be 1.22 times higher in males than females, especially beyond 36 years of age. The frequency peaks are: pure (= 100 per cent) CaOx 36-45 years; CaOx with additional mineral phases (mostly CaP) 46-55 years; uric acid 56-65 years; CaP 26-35 years. From those patients who underwent further investigations in searching for metabolic abnormalities serum concentrations, urine mineral clearances in fasting urine samples, and activity products of stone forming mineral phases in sequentially collected specimens from 24 h and 2 h fasting urine had been measured and compared with values from healthy control subjects. In urolithiasis (idiopathic) there is a normal parathyroid hormone blood level, a generally lower serum inorganic phosphate and magnesium concentration. In pure (= 100 per cent) CaOx and uric acid lithiasis serum uric acid and creatinine are higher than in controls, urine pH and calcium clearance in some groups are different too. Clearances of magnesium, uric acid, phosphate, sodium are within normal limits in urolithiasis. When expressing the propensity to form stones in terms of activity products, then only uric acid lithiasis deviates substantially from normal. All other stone types differ only slightly or not at all from each other and controls respectively. It is concluded that 1) in our geographic region the various stone types prevail in different age periods; 2) there are distinct alterations of parameters of mineral metabolism in urolithiasis; 3) measuring urine clearances may lead to assume falsely normal mean urine excretion of stone forming constituents.

The influence of citrate on intestinal calcium absorption (CaA) was studied in eight healthy males. On separate occasions, either a load containing 5 mmol of calcium chloride and 21 mmol of citrate in the form of sodium potassium citrate or a citrate-free vehicle load corrected for pH and cations was ingested. CaA was measured over 3 h with a 47Ca-85Sr double tracer method. After citrate administration, 10 min fractional CaA decreased significantly from 30 to 110 min post-load, and 3 h cumulative CaA dropped to 54.6 +/- (SEM) 6.1% of the total dose as opposed to 76.3 +/- 4.5% after vehicle administration (P less than 0.002). Citrate administration raised serum and urinary citrate, but had little effect on blood acid-base status. After both loads, urinary specific activity of 47Ca significantly correlated with 3 h cumulative CaA, while citrate administration decreased urinary calcium excretion only slightly as compared with vehicle. The results suggest that, in man, higher doses of oral citrate inhibit CaA, probably by way of intraluminal complexation of calcium by citrate. The finding might help explain the fall in urinary calcium excretion observed in patients treated with alkali citrate for recurrent calcium urolithiasis.