The presence of ascorbic acid in gastric juice may protect against gastric carcinoma and peptic ulceration. This study examined the effect of Helicobacter pylon (H pylon) on the secretion of ascorbic acid into gastric juice by measuring fasting plasma and gastric juice ascorbic acid concentrations in patients with and without the infection and also before and after its eradication. Gastric juice ascorbic acid concentrations in 19 H pylon positive patients were significantly lower (median 2*8, range 0-28*8 [ig/ml) than those in 10 H pylori negative controls (median 17-8, range 5*6-155*4 ,ug/ml) (p<0.0005) despite similar plasma ascorbic acid concentrations in both groups. The median gastric juice:plasma ascorbic acid ratio in the H pylon positive patients was only 1*16 (range 0.02-6.67), compared with a median ratio of 4*87 (range 0*76-21.33) in H pylon negative controls (p<001). In the patients with H pylon infection there was a significant negative correlation between the severity of the antral polymorphonuclear infiltrate and gastric juice ascorbic acid concentrations (correlation coefficient -0.52, p=002). After eradication of H pylori in 11 patients, gastric juice ascorbic acid concentrations rose from 2*4 (0-12.8 [tg/ml) to 11*2 (0-50

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The kinetics of plasma noradrenaline (NA) were studied in 14 patients with cirrhosis and ascites and 13 normal subjects. [3H]noradrenaline ([3H] NA) was infused intravenously to steady state and the spillover of NA into plasma and its clearance from plasma calculated. The increase in plasma NA in the cirrhotic patients was due to an increase in NA spillover (14.5 vs 3.9 nmol min-1m-2; P less than 0.001). NA plasma clearance was also increased in the cirrhotic patients (3.5 vs 2.11 min-1m-2; P less than 0.01). Plasma NA and dihydroxyphenylglycol (DHPG), a metabolite of NA of which a portion is formed after re-uptake of NA into sympathetic nerve endings, were then measured in 23 patients with cirrhosis and ascites, 17 patients with cirrhosis who had never had ascites, and 34 normal subjects. Both plasma NA and DHPG were significantly increased in the patients with ascites (NA 4.7, DHPG 14.7 nmol l-1 and in the patients with cirrhosis but no ascites (NA 3.8, DHPG 12.0 nmol l-1) compared with normal subjects (NA 1.9, DHPG 8.8 nmol 1-1). Therefore, the increase in plasma NA in cirrhosis is due to increased activity of the sympathetic nervous system rather than interference with the metabolism of NA or impaired neuronal uptake of NA. This increase appears to precede the development of ascites.

Plasma levels of norepinephrine (NE) and the NE metabolite 3,4-dihydroxyphenylethylene glycol (DHPG) were measured simultaneously following sympathetic activation induced by standing, cold pressor testing and bicycle exercise at progressively increasing workloads in normal volunteers. Free DHPG and NE levels both increased with sympathetic activation, but free NE levels were a more sensitive index of change. In addition, plasma free NE levels more closely reflected the fall in heart rate following exercise than free DHPG. In contrast to free levels, conjugated DHPG and NE levels did not change significantly after exercise. Supine resting free DHPG/NE ratios were always greater than 2.0, but fell progressively with increasing sympathetic activation because of a proportionately greater rise in NE than DHPG. The simultaneous measurement of plasma free DHPG and NE does not offer advantages over free NE levels as an index of sympathetic activity in man, but may be of use in the diagnosis of pheochromocytoma and in studies of NE metabolism.