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Biomedical subjects

G Celle

Publications and source records attributed to G Celle.

At least 91 records · Page 5Linked to original sources
PubMed1990

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)

Antimony↗
PubMed1990

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.

Acute Disease↗
PubMed1990

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.

Amylases↗
PubMed1990

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.

Adult↗
PubMed1989

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.

Adult↗
PubMed1989

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.

Adult↗
PubMed1989

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.

Adult↗
PubMed1989

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.

Animals↗
PubMed1989

Comparison of the effects of placebo, ranitidine, famotidine and nizatidine on intragastric acidity by means of continuous pH recording.

The effects of single daily doses of placebo, nizatidine 300 mg, ranitidine 300 mg and famotidine 40 mg, given at 22.00 h, have been compared in 16 patients with healed duodenal ulcers. Each of them underwent the above treatment on four separate occasions. The three H2 receptor antagonists showed a significantly higher acid inhibition than placebo (p less than 0.003) throughout the whole 24-hour period. Famotidine turned out to be more effective than nizatidine (p less than 0.02) in reducing circadian acidity, while there was no difference between ranitidine and nizatidine. The effects of the three H2 blockers on overnight acidity (from 23.00 to 07.00) were similar to each other, whereas both famotidine (p less than 0.003) and ranitidine (p less than 0.02) produced more anacidity than nizatidine during the morning hours (from 07.00 to 12.00). The time period elapsed in consecutive minutes above 5.0 pH units during drug-related events was significantly longer with both famotidine (p less than 0.01) and ranitidine (p less than 0.01) compared to nizatidine. Therefore in the recommended dosages for clinical use the acid suppression of nizatidine was significantly shorter-lasting than that of both ranitidine and famotidine. The major change is represented by the lack of carryover effect of nizatidine on morning acidity.

Adult↗