Antimony and glass pH electrodes can be used interchangeably in 24-hour studies of gastric acidity

Antimony and glass pH electrodes show almost identical experimental errors in continuously measuring buffer solutions at constant temperature over 24 hr. These errors are lower than the nominal quantization error of the instruments and are not properly described by the 24-hr drift determination. The addition of food particles to the solutions can induce severe reading artifacts. The longer response time reported in vitro of antimony electrodes when moving from pH 1 to pH 7 (3.4 sec vs 0.8 sec with glass electrodes) is irrelevant during in vivo pH-metry studies, because we found that the greatest absolute difference between raw fast acquired (4-6 sec) consecutive pH readings of two commonly used devices was 0.7 pH units in circadian profiles obtained from 413 subjects with various clinical conditions. In our in vivo studies, gastric acidity was monitored continuously with two side-by-side minielectrodes, which were variously combined (antimony-glass, A-G; antimony-antimony A1-A2; glass-glass, G1-G2) and applied on groups of 27 subjects matched for clinical condition. The 24-hr pH means and the 24-hr [H+] means calculated from the acidity profiles obtained with the three electrode combinations, lie on the identity line in each group. Using the Bland-Altman technique for assessing measurement agreement, the differences between the 24-hr pH means and the 24-hr [H+] means obtained with the three combined systems are similar (P = .903 and P = 0.824, respectively) and their 95% confidence limits are comprised within the range (+/-) of the reading error of the measuring systems (namely, +/- 0.3 pH units and +/- 12 mmol/liter in terms of [H+]).(ABSTRACT TRUNCATED AT 250 WORDS)

Patterns of dyspepsia in patients with no clinical evidence of organic diseases

We studied 2000 dyspeptic patients with no obvious signs of organic disease at their first examination, in order to (1) verify how many diagnoses of idiopathic dyspepsia had really been made after exhaustive diagnostic procedures and (2) evaluate the diagnostic power of the symptoms in distinguishing organic from idiopathic dyspepsia. This latter was considered only when no structural abnormalities were found. In all the other cases, a distinction was made between "related" and "associated" organic dyspepsia according to whether or not there was a certain relationship between the abnormalities and the dyspeptic symptoms. The patients were referred to us as follows: (1) spontaneously, (2) sent by physicians collaborating with us, (3) referred to our open access endoscopic service. The results show the frequency of idiopathic dyspepsia was 26%, whereas associated structural abnormalities were present in 45.4%. Obvious organic causes of dyspepsia were seen in 28.6% (24% benign and 4.6% malignant diseases). When considered separately, no symptom alone allows a correct diagnosis. The simultaneous evaluation of the symptoms with linear discriminant analysis distinguishes between idiopathic and organic dyspeptic patients in about 70% of the cases. A higher discrimination percentage in about 70% of the cases. A higher discrimination percentage could probably be obtained using a wider range of clinical parameters and/or a more complex statistical analysis of the interrelationships which exist between the clinical symptoms and the final diagnosis.

Effects of triglycylvasopressin on portal pressure and portal bile acid concentration in normal and cirrhotic rats

The effects of triglycylvasopressin on portal vein pressure and portal bile acid concentration after oral loading with chenodeoxycholic acid were evaluated in normal and cirrhotic rats. Triglycylvasopressin significantly reduced the portal vein pressure and portal bile acid concentration in both populations (normal: portal vein pressure 21.2%, p less than 0.05; portal bile acid concentration 43.2%, p less than 0.005; cirrhotic: portal vein pressure 19.8%, p less than 0.025; portal bile acid concentration 20.3%, p less than 0.05). Both in normal and cirrhotic rats, portal vein pressure and portal bile acid concentration resulted correlated. These results support that the combined determination of portal vein pressure and portal bile acid concentration could represent an interesting approach to the study of drugs which are potentially active on portal circulation and could indirectly provide information as to portal flow.

Modifications in the serum concentrations of prolyl hydroxylase in patients with chronic hepatitis B during and after interferon therapy

A total of eight patients with chronic active HBsAg-positive hepatitis was treated with recombinant interferon-alpha 2b for 12 months and serum aspartate aminotransferase, alanine aminotransferase, gamma-globulin and prolyl hydroxylase concentrations were determined every 3 months. Liver biopsies after 12 months' treatment revealed a significant (P less than 0.05) reduction in the histological activity score. After 6 months, alanine aminotransferase (P less than 0.01) and aspartate aminotransferase (P less than 0.05) concentrations fell significantly compared with baseline concentrations. Serum prolyl hydroxylase concentrations declined significantly (P less than 0.05) after 15 months and remained depressed. It is concluded that interferon-alpha 2b therapy reduced fibrogenetic activity in chronic active hepatitis B.

A single-blind pilot study comparing standard and half bedtime doses of ranitidine in the short-term healing of duodenal ulcer

In this two-center, pilot trial we assessed the efficacy of single bedtime does of 150 mg ranitidine (half dose) and 300 mg ranitidine (full dose) in promoting duodenal ulcer healing by comparing the proportions of healed ulcers after 4 and 8 weeks of treatment. One hundred thirty-nine patients (106 men) were randomly allocated according to a prearranged treatment schedule to either dose and were treated single-blind (endoscopist). One hundred twenty-six patients (63 given 150 mg ranitidine and 63 given 300 mg) completed the trial. In the per-protocol analysis, 55 patients given full doses (81%) and 47 given half doses (70%) of ranitidine had healed ulcers at 4 weeks. Sixty full-dose and 55 half-dose patients (95% and 87%, respectively), had healed ulcers at 8 weeks. The difference was not significant using the chi 2 test (two-tailed), but the 95% confidence limits were in favor of the 300-mg dose. This study had a 75% power to detect a 25% difference in healing rates between the two groups.

Trophic response and morphological changes in pancreas of caerulein treated rats: dose and time dependent effects

The present study was performed to determine the effect of the duration of chronic caerulein administration given at different doses, on the rat pancreas. Four groups of rats, one treated with 0.9% NaCl (control) and the others with caerulein 2, 5 and 10 micrograms/Kg twice a day i.p. were used. After a treatment period of 15, 30 and 60 days, 6 rats from each group were anesthetized, the pancreas was removed, and growth and composition of pancreatic tissue were determined. Small samples were taken for histological examination. Caerulein induced pancreatic hyperplasia and hypertrophy. The dose of caerulein used and the length of the treatment did not significantly modify the trophic effect. Focal perivascular and periductular lymphomonocytic infiltrates associated with cellular abnormalities were seen at 30 and 60 days. The results suggest that 1) the trophic effect of caerulein is not dose-and-time dependent and 2) morphological abnormalities can appear during long term treatment with CCK analogous.

Analysis of circadian fluctuations of bile salt concentration and pH in the stomach of normal subjects and patients suspected of having duodenogastric reflux

This study was undertaken to evaluate whether intrigastric pH measurements and bile salt concentrations show synchronous fluctuations, in both postprandial and fasting states. It was performed on 5 normal volunteers and 17 non-operated patients suspected of having duodenogastric reflux. In controls the two variables showed different behaviour, especially after eating, while in suspected refluxers they presented more synchronous elevations both in postprandial states and in the nocturnal period. The first derivatives of both pH and bile salt interpolations using Fourier's truncated Series give evidence that these two variables behave differently in the time domain of the two groups. In fact, their first derivatives show equal signs for 521 min (36.2%) out of the 1440 of the study in controls (p less than 0.05) and for 1024/1440 min. (71.1%) in suspected refluxers (p less than 0.005). The difference between the time elapsed in min with equal sign derivatives in the two groups is significant (p less than 0.005). Despite this more coherent behaviour of pH and bile salt fluctuations in patients with suspected reflux, the two variables do not present coincident numerical values even in this population and therefore a close quantitative relationship between them can be excluded in both groups. As a consequence of these results, the use of bile salt concentrations seems inadequate to validate the fact that alkalinizations observed in pH-metry studies are related to episodes of duodenograstric reflux.

[Acid-related pathology and prolonged continuous gastric pH monitoring. Physiopathologic findings and therapeutic implications]

Long-term measurement of gastric acidity is useful for the investigation of acid-related disorders of the upper gastrointestinal tract and for the evaluation of antisecretory drugs. The assessment of this function with intragastric minielectrodes connected to ambulatory solid-state recorders is increasingly being used and is replacing the traditional aspirative methods. Antimony and glass electrodes provide equivalent results in vivo and thus they can be used interchangeably in every clinical condition. In normal subjects and in patients with acid-related disorders this technique has the great advantage to allow us an accurate knowledge not only of the level but also of the variations of gastric acidity over time, in relation to usual events of daily life. Clinical pharmacological studies permit to define exactly the potency and the duration of action of antisecretory compounds, the effects of various doses of the same drug and their best administration time.

Cerebral blood flow and plasma free tryptophan in cirrhotics with and without hepatic encephalopathy

Cerebral blood flow (CBF), measured by the non-invasive 133-Xenon inhalation method, plasma levels of ammonia (NH3) and free tryptophan (fTRP) were determined in 30 cirrhotic patients without overt encephalopathy. Psychometric evaluation detected subclinical hepatic encephalopathy (SHE) in 20 of them, and was normal in the other 10. A significant CBF difference (p less than 0.05) was found between the SHE and the non-SHE patients. fTRP levels were significantly (p less than 0.05) higher in patients with SHE than in those without SHE, and a significant negative correlation (p = 0.003) was found between CBF values and fTRP in the whole group of patients. NH3 did not differ in the two subgroups and did not correlate with CBF values. It is concluded that CBF could have some implications in SHE, although its relevance is still unclear. The negative correlation between CBF and fTRP prompts further investigation concerning the relationships between plasma fTRP, brain serotonin, cerebral metabolism and blood flow in the development of brain derangement during cirrhosis.

Low bedtime doses of H2-receptor antagonists for acute treatment of duodenal ulcer

Twenty-four-hour intragastric acidity was measured continuously over five separate occasions in 15 patients with healed duodenal ulcers. They were randomized to receive either placebo, cimetidine 800 mg, ranitidine 150 mg, famotidine 20 mg, or nizatidine 150 mg, given at 2200 hr in double-blind fashion. All H2-receptor blockers were more effective than placebo in suppressing both circadian (P less than 0.05-P less than 0.01) and nocturnal (P less than 0.002) gastric acidity, while there was no significant differences between the effects of the four active drugs in the same time periods. The percentage of nocturnal acid inhibition (2300-0800 hr) over placebo in terms of H+ values was virtually 100% with all active treatments. The effect on daytime (0800-1700 hr) and evening (1700-2300 hr) acidity of both placebo and the four H2-receptor antagonists was similar. Therefore, in the above doses H2-receptor blockers guarantee overnight anacidity to a similar degree and cause the physiological buffering of daily meals on gastric acidity to be fully exploited. Furthermore, the reducing effect of daily meals on drug action can be prevented. Since strong acid suppression strictly confined to the nocturnal period has been shown to be closely correlated with the highest ulcer healing rates, it is suggested that single low bedtime doses of H2-receptor antagonist should be evaluated in the acute treatment of duodenal ulcer.

Gastric aspiration versus antimony and glass pH electrodes. A simultaneous comparative in vivo study

To carry out a simultaneous comparison of the 24-h in vivo performance of antimony and glass electrodes and the findings of intermittent gastric aspiration, a triple-probe system with closely adjacent tips was positioned in the gastric corpus of 10 subjects representing different clinical and pharmacologic conditions. We showed that pH values measured with the antimony and the glass units were well correlated to those assessed in gastric aspirates (rs = 0.87; b = 1.079; a = -0.33; and rs = 0.85; b = 1.121; a = -0.38, respectively). A proportional correlation (rs = 0.86; b = 0.97; a = 0.02) was also found between the two intraluminal pH measurements. With regard to the error frequency distributions obtained by comparing the three measuring systems two at a time, the pH pairs differed by no more than 1 pH unit in most cases (greater than 90%). It can be concluded that antimony and glass pH electrodes can be used interchangeably in 24-h intragastric acidity studies in man.

Tryglycylvasopressin-reduced portal and systemic concentrations of serum bile acids after exogenous chenodeoxycholic acid load in rats as a reflection of reduced splanchnic blood flow

The effect of triglycylvasopressin (TGVP) on the absorption of chenodeoxycholic acid (CDCA) was investigated in three groups of six rats (controls, CDCA, CDCA + TGVP) through the evaluation of portal and caval serum bile acids (SBA) concentrations after an oral load with CDCA to investigate whether changes in this parameter reflect variations in splanchnic blood flow induced by a vasoconstrictor. The results indicate that CDCA was absorbed and led to a significant increase in SBA. This increase was reduced by TGVP administration: portal blood 380.0 +/- 61.2 vs 279.7 +/- 45.3; caval blood 151.8 +/- 45.7 vs 41.7 +/- 12.5 (mumol/l; mean +/- s.d.). This suggests that variations in SBA concentrations could reflect changes in splanchnic circulation.

Antimycobacterial chemotherapy in inflammatory bowel disease

We report on a case, ulcerative colitis and another of Crohn's disease. During a relapse which was unresponsive to conventional therapy, acid-fast bacilli were found in colonic biopsies. Conventional therapy was substituted with antimycobacterial chemotherapy (rifampicin, isoniazid and ethambutol) which was responsible for a marked improvement. However, a relapse occurred during chemotherapy and no acid-fast bacilli were found. The patients became responsive to sulphasalazine and corticosteroid therapy once again. It appears that Mycobacteria play a collateral role in inflammatory bowel disease and that once they have been eliminated the original disease re-emerges.