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Bismuth compounds remain useful for Helicobacter pylori eradication therapy. These include colloidal bismuth subcitrate (CBS), bismuth subsalicylate (BSS) and, most recently, ranitidine bismuth citrate (RBC). CBS appears to prevent the development of imidazole resistance when coadministered with nitroimidazoles. Traditional triple therapy with bismuth, metronidazole and tetracycline or amoxicillin (BMT/A) only partially overcomes metronidazole resistance. However, the addition of a PPI to bismuth triple therapy largely overcomes established metronidazole resistance if treatment is given for at least one week or more. When RBC rather than PPI is used with clarithromycin, this dual regimen appears to be more effective in preventing the development of secondary clarithromycin resistance. The triple combination of RBC, metronidazole and clarithromycin appears to be effective against metronidazole resistant strains of H pylori. Thus, overall, there is some evidence that bismuth compounds may prevent the development of antibiotic resistance and that existing antibiotic resistance may at least be partially overcome in vitro and in vivo. With the growing emergence of H pylori resistance to metronidazole and clarithromycin, further research to clarify the role of bismuth compounds is required.
A 17-bed intensive care unit in a university teaching hospital. PATIENTS. In phase 1 there were 736 patients and in phase 2737. Those in the two phases were comparable in age and reason for admission; clinically significant gastrointestinal bleeding rates did not differ between the two phases, but patients in phase 2 were more severely ill.
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The effects of pirenzepine and ranitidine alone and combined, on gastric acid secretion and gastrin release stimulated by liquid peptone meal were evaluated in 12 duodenal ulcer patients. Six patients received placebo and ranitidine 150 mg per os and the other six patients were given placebo, pirenzepine 50 mg and pirenzepine 50 mg plus ranitidine 150 mg per os, according to randomized sequences. In the first experiment ranitidine markedly inhibited (69%) gastric acid secretion for entire two hours period (p less than 0.01). In the second experiment acid secretion after pirenzepine, was reduced by 39% while the combination of pirenzepine plus ranitidine almost completely inhibited the meal stimulated acid secretion (99%). Mean integrated gastrin responses after pirenzepine and ranitidine alone as well as pirenzepine plus ranitidine were not significantly different from placebo. The results of these studies show that in duodenal ulcer patients, the simultaneous block of muscarinic and H2-receptors, suppresses meal stimulated gastric acid secretion, without affecting gastrin release. This therapeutic combination might be used in clinical situations (non-responders, Zollinger-Ellison syndrome) in which complete inhibition of gastric acid secretion is needed.
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Reactive oxygen species (ROS) have been implicated in the etiology of indomethacin-induced gastric mucosal damage. This study investigated ascorbic acid (vitamin C)'s protective effects against oxidative gastric mucosal damage induced by indomethacin. Ascorbic acid is a powerful antioxidant because it can donate a hydrogen atom and form a relatively stable ascorbyl free radical. We have investigated alterations in the levels of myeloperoxidase, antioxidant system enzymes (glutathione S-transferase, superoxide dismutase, glutathione reductase, catalase, glutathione peroxidase), lipid peroxidation and glutathione, as markers for ulceration process following oral administration of ascorbic acid, famotidine, lansoprazole, and ranitidine in rats with indomethacin-induced ulcers. In the present study, we found that (1) ascorbic acid, famotidine, lansoprazole and ranitidine reduced the development of indomethacin-induced gastric damages; (2) the administration of indomethacin caused a significant decrease in the levels of superoxide dismutase, glutathione peroxidase, glutathione S-transferase and glutathione, and an increase in the lipid peroxidation level; (3) the administration of ascorbic acid reversed the trend, inducing a significant increase of these enzymes' levels and a reduction in lipid peroxidation level in tissues; and (4) catalase, glutathione reductase and myeloperoxidase activities, increased by indomethacin, were found to be lower in the ascorbic acid, famotidine, lansoprazole and ranitidine-treated groups. The results indicate that the gastroprotective properties of ascorbic acid could be related to its positive effects on the antioxidant system and myeloperoxidase activity in indomethacin-induced gastric ulcers in rats.
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Peptic ulcers can be treated successfully with antisecretory drugs and drugs which have a protective effect. Thanks to their good tolerance and a form of administration acceptable to patients, the H2-receptor antagonists have won a leading position amongst the other ulcer therapeutics. It remains to be seen whether the substituted benzimidazoles will develop into a serious competitor. Until now the clinical experiences with the prostaglandins in the treatment of ulcers are not very encouraging.
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Stress-related gastric mucosal damage is a common occurrence in intensive care unit (ICU) patients. Because of the significant morbidity and mortality associated with this mucosal damage, many ICU patients routinely receive prophylactic therapy, usually with histamine H2-receptor antagonists (H2RAs). Gastric acid secretion occurs in a circadian pattern, with late afternoon and evening surges. H2RAs by continuous infusion may control this uneven pattern of secretion more effectively than H2RAs given by bolus injection. More studies are needed to identify the target ICU population for prophylactic treatment.
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A 17-year-old boy who developed a symptomatic duodenal ulcer at 10 years of age with melena, and was then treated continuously for 6 years with ranitidine therapy that only partially controlled symptoms and peptic lesions, came to us with vomiting due to duodenal bulb stenosis and active ulcer. Four months of omeprazole (40 mg/die o.m.) did not modify the endoscopic picture. The diagnosis of H. pylori infection and its treatment with triple therapy led to the cure of both duodenal ulcer and bulbar stenosis. Afterwards he remained asymptomatic without any lesions or complications for 18 months. This case illustrates that H. pylori eradication: a) is able to cure refractory duodenal ulcer; b) resolves severe complications such as duodenal stenosis.
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Gastroesophageal reflux (GER) and tracheal aspiration of acid may increase morbidity and mortality in patients undergoing thoracotomy. This randomized, double-blinded, placebo-controlled study demonstrates frequent incidences of both acid GER and tracheal acid aspiration during surgery that are significantly reduced by premedication with ranitidine.
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Numerous environmental and genetic factors have been implicated in the pathogenesis of peptic ulcer disease. Although the cause of this disorder has not been established, acid pepsin has been acknowledged at least as a permissive factor in its development. More important, inhibition of nocturnal or 24-hour intragastric acidity is predictably associated with ulcer healing. Famotidine 40 mg at bedtime maintains approximately one-third of pH readings at or above 3.5, reduces pepsin activity, and has no adverse effect on mean total serum gastric concentrations after one week of therapy. In addition, the effect of this dose of famotidine is comparable to ranitidine 300 mg at bedtime and predicts comparable rates of ulcer healing. Thus, monitoring of intragastric pH levels may be useful in identifying potent healers of peptic ulcer disease and in selecting optimal doses or timing of drug administration. Studies of famotidine using such measurements have suggested that this new H2-receptor antagonist is comparable to ranitidine in the healing of duodenal ulcers.
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To evaluate the clinical efficacy of available therapies directed towards Helicobacter pylori eradication.
N-nitrosodimethylamine (NDMA), a probable human carcinogen, is a disinfection by-product that has been detected in chloraminated drinking water systems. Pre-oxidation of the NDMA precursors prior to chloramination can be a viable approach for water utilities to control the NDMA levels. This study examined the effects of (i) commonly used oxidants (i.e., chlorine, chlorine dioxide and ozone) in water treatment, (ii) oxidant concentration and contact time (CT), and (iii) pre-oxidation pH on the formation of NDMA from subsequent chloramination. Fifteen model precursors with NDMA molar yields ranging from approximately 0.1%-90% were examined. Pre-chlorination reduced NDMA formation from most precursors by 10%-50% except quaternary amine polymers (i.e., PolyDADMAC, PolyACRYL, PolyAMINE). Pre-oxidation with chlorine dioxide and ozone achieved the same or higher deactivation of NDMA precursors (e.g., ranitidine) while increasing NDMA formation for some other precursors (e.g., daminozid). The increases with chlorine dioxide exposure were attributed to the release of oxidation products with dimethylamine (DMA) moiety, which may form more NDMA upon chloramination than the unoxidizied parent compound. On the other hand, chlorine dioxide was effective, if a precursors NDMA yield were higher than DMA. The ozone-triggered increases could be related to direct NDMA formation from DMA which are released by ozonation of amines with DMA moiety, amides or hydrazines. However, hydroxyl radicals formed from the decomposition of ozone would be also involved in decomposition of formed NDMA, reducing the overall NDMA levels at longer contact times. pH conditions influenced significantly the effectiveness of deactivation of precursors depending on the type of precursor and oxidant used.
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We report a patient--a 42-year-old man--who had suffered from recurrent duodenal ulcer for about 20 years. Successful curative therapy for Helicobacter pylori infection was performed for 2 weeks with new triple omeprazole, anoxicillin, clarithromycin (OAC) treatment in October 1995, and cure of the infection was repeatedly confirmed by histology, culture, and the 13C urea breath test. One month after the curative therapy, recurrence of a small duodenal ulcer was observed and in February another duodenal ulcer and reflux esophagitis occurred, with severe symptoms, despite the continuous administration of ranitidine. None of the examinations to reconfirm cure of the infection revealed the presence of H. pylori. As the patient experienced continual psychological stress and smoked more frequently during the recurrent episode and had not used nonsteroidal anti-inflammatory drugs, stress and smoking appeared to play important roles in the relapse of duodenal ulcer in this patient after cure of H. pylori infection.
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Combination preparation plays an important role in clinical treatment because of its better and wider curative synergism and weaker side effects. However, the existence of incompatibility between active ingredients or between active ingredients and excipients presents a serious obstacle in the preparation of such combination solid dosage forms. In this study, aspirin and ranitidine hydrochloride, between which there existed a chemical interaction, were selected as model drugs. Aspirin powders without any additives were granulated with hydroxypropyl methyl cellulose (HPMC) water solution as a binder using a Wurster coating apparatus and the operation conditions were optimized by Artificial Neural Network (ANN) analysis. Under these conditions, the aspirin granules prepared showed good flowability and compressibility. On the other hand, ranitidine hydrochloride was coated with Aquacoat (ethyl cellulose aqueous dispersion) after preliminary granulation with the Wurster coating apparatus. The aspirin granules and coated ranitidine hydrochloride particles were compressed into tablets with suitable excipients. The combination tablets showed good dissolution, content uniformity and improved stability of active ingredients.
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Levodopa (l-dopa) remains the best drug in the treatment of Parkinson's disease (PD). Unfortunately, long-term l-dopa caused motor complications, one of which is l-dopa-induced dyskinesia (LID). The precise mechanisms of LID are not fully understood. We have previously reported that ranitidine could reduce LID by inhibiting the activity of protein kinase A pathway in a rat model of PD. It is demonstrated that neurotransmitters such as γ-aminobutyric-acid (GABA) and glutamate (Glu) are also involved in the expression of LID. But whether ranitidine could reduce LID by remodeling the neurochemical changes is unknown.
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Polymorphs of a similar purity yielded virtually identical moisture sorption profiles. In contrast, samples containing higher levels of impurities had both enhanced moisture sorption below RH0 and a lowered value of RH0.
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Echocardiography laboratory at a university hospital.
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When HL-60 cells were stimulated with histamine, a significant differentiation of the cells toward neutrophils was elicited. Histamine increased phagocytic activity, but it reduced myeloperoxidase activity of HL-60 cells. Histamine-induced differentiation in HL-60 cells was inhibited not only by H2 antagonists, such as cimetidine, ranitidine and famotidine, but also by an inhibitor of protein kinase A (A kinase), KT-5720. Histamine increased the cAMP level and A kinase activity in HL-60 cells; both increases preceded the cell differentiation. Histamine also enhanced phosphorylation of a 160 kD protein in HL-60 cells, while H2 antagonists and KT-5720 inhibited this phosphorylation. The results of the present study indicate that an activation of A kinase via H2 receptor stimulation may cause the phosphorylation of a 160 kD protein and that this phosphorylation is probably involved in the process leading to differentiation of HL-60 cells.
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This study was to investigate the gastrokinetic activity of Morinda citrifolia aqueous fruit extract (AFE) in human subjects by examining the GI absorption of ranitidine, a putative indicator of GI motility and to elucidate its possible gastrokinetic mechanism of action in rats.
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The aim of this study was to compare in an open trial the efficacy of 2 x 500 mg clarithromycin + 2 x 1000 mg amoxicillin + 40 mg pantoprazole/day given for 7 days (I. group, 48 cases), with that of 2 x 500 mg clarithromycin + 2 x 400 mg ranitidine bismuth citrate/day given for 14 days (II. group, 51 cases). The diagnosis of peptic ulcer was established endoscopically. HP infection was confirmed the modified Giemsa stain and rapid urease test. After eradication all patients were given 2 x 150 mg ranitidine for one month. Controls were performed 4-6 weeks after eradication. Peptic ulcer healing was proven in the group I in 93.0% and in the group II in 91.6% (p > 0.05). On intention-to-treat basis, HP was eradicated in 80.3% (confidence interval, CI: 73-92.7%) in the I. and 80.3% (confidence interval: 76-95%) in the II. group (p > 0.05). Per protocol analysis revealed eradication rates of 88.3% (CI: 81-97.6%) and 85.4% (CI: 80-97%) (p > 0.05). Side effects were recorded in 9.5% and 14.5% of the cases. Both regimens were equally effective in the eradication of HP and healing of peptic ulcers.
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The efficiency of stress ulcer prophylaxis in the prevention of gastrointestinal bleeding in critically ill patients has led to its widespread use. The lower incidence of stress ulcer bleeding, the side-effects and the cost of the prophylaxis have made it necessary targeting this preventive therapy to those patients most likely to benefit. Metaanalysis of studies on patients who received no stress ulcer prophylaxis showed few critically ill patients with important gastrointestinal bleeding.
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Currently, ranitidine dose recommendations are based on children's weights. However, our findings suggest that a dosing scheme that takes into consideration both weight and cardiac failure/surgery would be more appropriate in order to avoid administration of higher or more frequent doses than necessary.
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To assess the cost effectiveness of a multidrug prepackaged regimen for Helicobacter pylori, the Hp-PAC (lansoprazole 30mg, clarithromycin 500 mg, amoxicillin 1 g, all twice daily), relative to alternative pharmacological strategies in the management of confirmed duodenal ulcer over a 1-year period from 2 perspectives: (i) a strict healthcare payer perspective (Ontario Ministry of Health) excluding the patient copayment; and (ii) a healthcare payer perspective including the patient copayment.
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1 Ranitidine single dose pharmacokinetics and absolute bioavailability have been studied in five healthy male volunteers. Following an overnight fast, 150 mg was given intravenously as a bolus injection or orally as a tablet formulation to each subject on separate occasions. 2 Following intravenous administration, plasma levels declined biexponentially. The mean (+/- s.d.) distribution half-life (t 1/2 alpha) was 6.6 +/- 1.6 min; plasma half-life (t 1/2 beta) was 1.7 +/- 0.2 h; the volume of distribution (V) was 96 +/- 9 1; total body clearance (CL) was 647 +/- 94 ml/min and renal clearance (CLR) 520 +/- 123 ml/min. 3 Following oral administration plasma levels showed a bimodal pattern with a first peak at 1.1 +/- 0.4 h and a second peak at 3 +/- 0 h. The absolute availability was 60 +/- 17%. The plasma half-life (t 1/2) of 2.3 +/- 0.4 h was significantly longer (P less than 0.05) after oral than after i.v. administration. 4 Renal excretion of unchanged ranitidine accounted for 79 +/- 9% of the dose after i.v. administration and for 27 +/- 7% after oral administration. 5 Our results suggest a more extensive biotransformation of ranitidine and biliary excretion of metabolites after oral administration while i.v. administration ranitidine is preferentially excreted unchanged in the urine.
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Acid secretion inhibitors are of dubious value to most patients with functional dyspepsia but might be effective in a subset. The aims of the trial were to compare the effect of ranitidine with that of placebo in selected subsets of patients.
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Parietal cell sensitivity is increased in patients with active duodenal ulcer. It has been shown to increase in healthy volunteers after a 4-week treatment with H2-receptor blockers. Metaanalyses of therapeutic trials have indicated that time to first relapse was longer after ulcer healing with prostaglandins (PG) than after healing with H2-receptor blockers, which might be due to a different effect of the two treatments on parietal cell sensitivity. OBJECTIVES--To study, in healthy volunteers, basal gastric acid secretion, acid secretory responses and parietal cell sensitivity to histamine before and after a 4-week treatment with enprostil (E) and ranitidine (R). METHODS--This was a randomized double-blind double-dummy crossover study. Twelve male healthy volunteers (22-44 years) were randomly assigned to receive a 4-week treatment with either E (35 micrograms bid) or R (150 mg bid). After a 2-month washout period, they were crossed to the alternate treatment. Basal acid output (BAO), acid secretory responses to low-dose histamine infusion (histamine dihydrochloride 2.5 micrograms/kg/h) (LDAO), to a high-dose histamine infusion (25 micrograms/kg/h) (HDAO) and parietal cell sensitivity (PCS = LDAO/HDAO x 100) were measured 24 hours before the first administration and 72 hours after the last administration of each medication. RESULTS--All secretory parameters were similar before treatment with E and R. As compared to pretreatment values: a) HDAO tended to increase after both treatments (NS); b) LDAO (m +/- sem) slightly increased after R (18.4 +/- 2.6 vs 13.9 +/- 3.3 mEq) (NS) but not after E (12.5 +/- 1.8 vs 13.2 +/- 1.9 mEq); c) PCS (m +/- sem) was unchanged after R (36 +/- 4 vs 33 +/- 6) but decreased after R (30 +/- 6 vs 36 +/- 0.5; P < 0.02). When secretory parameters after treatment with R and treatment with E were compared, the difference was significant for LDAO (P < 0.02) and PCS (P < 0.05). CONCLUSIONS--If also found in patients with duodenal ulcer disease, these results might, at least partly, explain the lesser propensity of the ulcers to relapse early after healing with PG than after healing with H2-receptor blockers. However enprostil has been with-drawn from the market and it is now well established that one factor influencing the relapse rate is the efficiency of the treatment given to achieve ulcer healing in eradicating Helicobacter pylori. Consequently, the interest of our results is presently mostly physiological.
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Helicobacter pylori is the causative agent of gastritis and a co-agent in other gastroduodenal diseases. Gastroduodenal ulcer and MALT-lymphoma in particular, regress when patients are administered antimicrobial agents to eradicate infection. Sometimes eradication is not definitive and is difficult to check. The aim of our study was to test the antimicrobial activity of omeprazole on H. pylori in comparison with ampicillin and other anti-H2 drugs (ranitidine and famotidine), and to evaluate their interference with bacterial adhesion of H. pylori. We also compared results of the agar dilution antibacterial sensitivity test on H. pylori to those obtained using a bacteria adherence to cell monolayers model, to see if drug activity was different against adhered bacteria. We evaluated omeprazole and ampicillin MIC90s (minimum inhibitory concentrations) against 20 H. pylori isolates by traditional agar dilution method and by exposing previously adhered bacteria to an Hep-2 monolayer to different drug concentrations. The activity against bacteria adhered to cell lines was evaluated by counting viable adhered bacteria after 1, 6, 12 hours of contact with drug. Interference with adherence to Hep-2 cells was also tested. Omeprazole and ampicillin MICs were comparable to other findings (omeprazole MIC90 was 12.5 microg/ml and ampicillin MIC90 was 0.016 microg/ml), while higher concentrations were necessary (4 x MIC90) against adhered bacteria. These findings suggest that MICs evaluated with traditional assays can have different predictivity than tests on adhered H. pylori.
Basophils are circulating granulocytes, best known as effector cells in allergic reactions. Recent studies in mice suggest that they might also participate in the suppression of chronic inflammation. The aim of this study was to assess the ability of purified human basophils to modulate monocyte responses upon IL-33 and IgE triggering. Activation of human basophils with IL-33 induced the production of IL-4 and the release of histamine, and enhanced their IgE-mediated activation. In addition, basophils triggered with IL-33 and anti-IgE significantly suppressed the LPS-induced production of the proinflammatory cytokine TNF-α and the upregulation of the costimulatory molecule CD80 by monocytes. These effects were mainly explained by the release of histamine, as they could be inhibited by the histamine receptor 2 antagonist ranitidine, with a smaller contribution of IL-4. In contrast, basophil-derived IL-4 and histamine had opposing effects on the expression of the inhibitory Fc γ receptor IIb and the production of IL-10 by monocytes. Our data show that basophils can influence monocyte activation and suggest a previously unrecognized role for human basophils in the modulation of monocyte-mediated immune responses, through the balanced secretion of histamine and IL-4.
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A double-blind, multicenter, randomized study was performed in 75 patients with endoscopically documented reflux esophagitis. Patients were randomly given 1 g sucralfate four times a day or the combination of sucralfate three times a day and 300 mg ranitidine after dinnertime. Endoscopy was performed at the beginning of the study, after 8 weeks, and, if, the reflux esophagitis was not healed, after 16 weeks. Four patients had to be excluded from evaluation; 71 patients could therefore be evaluated. Both groups showed symptomatic improvement to similar extents. Endoscopy showed symptomatic improvement in 67% of the patients treated with sucralfate and in 74% of the combination therapy group. Complete healing or Savary-Miller stage 1 was seen in 26.5% and in 31.4%, respectively. We conclude that sucralfate monotherapy in patients with milder forms of reflux esophagitis is comparable with a combination of sucralfate during the day and ranitidine after dinnertime. This study does not support the commonly used combination of sucralfate and H2-receptor antagonists in reflux esophagitis.
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Histamine type-2 receptor antagonists (H-2RA) have been used chronically to prevent dyspepsia in cancer patients subjected to immunotherapy with chronic indomethacin (Indo) and intermittent IL-2 in our cancer centre. We tested the effects of these agents during immunotherapy of C3H/HeJ mice transplanted s.c. with 5 x 10(5) C3L5 mammary adenocarcinoma cells. Tumor-transplanted mice were divided into groups receiving: (1) Indo (14 micrograms/ml); (2) H-2RA, i.e. (a) ranitidine at 28.6 micrograms/ml (Ran-lo) or 143 micrograms/ml (Ran-hi), or (b) famotidine (Fam) at 4.3 micrograms/ml, or (c) cimetidine (Cim) at 107 micrograms/ml, all in the drinking water on days 5-24; (3) IL-2 (1.5 x 10(3) Cetus U i.p. every 8 h on days 10-14 and 20-24); (4) combinations of H-2RA + Indo; or (5) combinations of H-2RA + Indo + IL-2. Animals were killed on day 24 for examination of primary s.c. tumor growth, secondary lung metastasis and splenocyte cytotoxicity against YAC-1 lymphoma cells (51Cr release assay). Results revealed: (1) primary tumor growth was reduced in mice treated with Fam + Indo, Indo + IL-2 and any of the H-2RA + Indo + IL-2 (no difference observed within the last two groups); (2) lung metastases decreased in mice treated with IL-2 alone, Indo + IL-2, and Indo + IL-2 + Ran-hi; (3) splenic cytotoxicity was suppressed in tumor-bearing controls, with partial restoration seen in Ran (both doses), Ran-lo + Indo, Ran-lo + Indo + IL-2, and Cim + Indo + IL-2 treated groups. Nearly complete restoration was seen in Cim, Cim + Indo, Indo + IL-2, Ran-hi + Indo + IL-2, and Fam + Indo + IL-2 groups. Thus, addition of H-2RA did not alter the overall therapeutic efficacy of the standard Indo + IL-2 tumor immunotherapy.