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Biomedical subjects

P Bytzer

Publications and source records attributed to P Bytzer.

84 records · Page 5Linked to original sources
PubMed1986

Enprostil and ranitidine in duodenal ulcer healing: double blind comparative trial.

One hundred and eighty patients with endoscopically proved duodenal ulcers were allocated at random to double blind treatment with the synthetic dehydroprostaglandin E2 enprostil 35 micrograms twice daily or ranitidine 150 mg twice daily for up to six weeks. Patients completed the study if ulcer healing and pain relief had occurred at two or four weeks. A total of 163 patients completed the trial. The duration of treatment was longer in the enprostil group (p less than 0.005) and the cumulative healing rates at two, four, and six weeks were 51%, 74%, and 85%, respectively. In the ranitidine group the corresponding figures were 65% (p less than 0.04), 89% (p less than 0.02), and 99% (p less than 0.002). More patients treated with ranitidine reported relief of pain (p less than 0.004 at weeks 5 and 6). The observed superiority of ranitidine 150 mg twice daily over enprostil 35 micrograms twice daily questions the clinical relevance of using so called "cytoprotection" as treatment for duodenal ulcer disease in the short term.

Adolescent↗
PubMed1986

Symptomatic recurrence of healed duodenal and prepyloric ulcers after treatment with ranitidine or high-dose antacid. A 1-year follow-up study.

Eighty-seven patients with duodenal (n = 49) or prepyloric (n = 38) ulcers healed with ranitidine (n = 44) or a high-dose liquid antacid (n = 43) completed a 1-year double-blind comparative study of symptomatic relapse without treatment. Both duodenal ulcers and prepyloric ulcers tended to remain true to their type of recurrence. Age, sex, history of ulcer disease, duration of initial treatment, and smoking habits were all without influence on the relapse rates. The subgroup of patients with a duodenal ulcer who had healed on either treatment regimen had a symptomatic relapse significantly more frequently than those with prepyloric ulcer (64% +/- 13 versus 34% +/- 15; p less than 0.025), but the estimated probabilities of relapse were unaffected (p greater than 0.05) by the initial type of medication (ranitidine group, 56% +/- 15; antacid group, 51% +/- 15). Thus the present study could not confirm the hypothesis that patients treated with H2-receptor antagonists tend to relapse earlier than those treated with antacids during the following year without treatment.

Antacids↗
PubMed1985

Effect of omeprazole and cimetidine on duodenal ulcer. A double-blind comparative trial.

We conducted a double-blind randomized study of 132 patients to determine whether the new, investigational proton-pump inhibitor, omeprazole (30 mg per day), would accelerate healing and pain relief, as compared with cimetidine (1 g per day), in patients with duodenal ulcer. After two weeks of treatment, which was completed by all patients, the healing rates were 73 per cent in the omeprazole group and 46 per cent in the cimetidine group (P less than 0.01). After four weeks of treatment, which was completed by 118 patients, the corresponding figures were 92 and 74 per cent (P less than 0.05). In the omeprazole group 55 per cent of the patients were free of pain after the first week, as compared with 40 per cent of those treated with cimetidine (P greater than 0.05). No major clinical or biochemical side effects of omeprazole or cimetidine were noted. A six-month follow-up study revealed no significant difference between the recurrence rates after omeprazole and after cimetidine treatment. In May 1984 clinical trials with omeprazole were temporarily suspended, since a study of long-term toxicity in rats had shown the development of gastric carcinoid tumors.

Adult↗
PubMed1985

Comparison of ranitidine and high-dose antacid in the treatment of prepyloric or duodenal ulcer. A double-blind controlled trial.

One hundred and nineteen patients with endoscopically confirmed prepyloric (n = 59) or duodenal (n = 60) ulcer were stratified for ulcer location before entering a randomized double-blind trial comparing ranitidine (150 mg twice daily) and a potent liquid antacid (Novaluzid; 10 ml seven times daily, with a neutralizing capacity of 600 mmol H+). Fifty-four patients with prepyloric (26 receiving ranitidine) and 53 patients with duodenal ulcer (28 receiving ranitidine) completed the trial in accordance with the protocol. The 4 and 6 weeks' healing rates for prepyloric ulcers were 54%, 68%, and 61%, versus 69%, 79%, and 74% for the ranitidine, the antacid, and whole groups, respectively. For duodenal ulcers these figures were 89%, 84%, and 87%, versus 100%, 96%, and 98% for the ranitidine, antacid, and whole groups, respectively. Differences in healing rates between treatments were statistically insignificant within strata for ulcer type, but healing rates for prepyloric ulcers were significantly lower than for duodenal ulcers (p less than 0.002). A significant early pain relief was found in all groups, and side effects, including diarrhoea, were rare. In conclusion, these two ulcer treatment modalities appear to be equally effective in the short term. In addition, the data emphasize the need for proper stratification of prepyloric and duodenal ulcers in clinical trials of ulcer healing.

Adult↗
PubMed1984

Effects of sulphasalazine and disodium azodisalicylate on colonic PGE2 concentrations determined by equilibrium in vivo dialysis of faeces in patients with ulcerative colitis and healthy controls.

The role of arachidonic acid metabolites and the mode of action of 5-aminosalicylic acid, the active moiety of sulphasalazine and disodium azodisalicylate, in ulcerative colitis remain obscure. Therefore, experiments were performed in which the effects of medication on immunoreactive prostaglandin (PG) E2 concentrations in free faecal water were assessed using the equilibrium in vivo dialysis of faeces. Colonic PGE2 concentrations in patients with active ulcerative colitis (n = 11) ranged from 2035-18,000 pg/ml to be compared with a range of 103-188 pg/ml in healthy volunteers (n = 10; p less than 0.001). In all healthy volunteers PGE2 concentrations decreased slightly (p less than 0.05) after disodium azodisalicylate intake 2 g/day, whereas low dose disodium azodisalicylate (0.25 g/day) caused no change. In patients with ulcerative colitis in complete clinical, sigmoidoscopic, and histologic remission withdrawal of sulphasalazine (2 g/day; n = 6) increased PGE2 concentrations to values above normal levels (p less than 0.05) which returned to pretrial values (p less than 0.05) on disodium azodisalicylate (2 g/day; n = 7). In conclusion, increased PGE2 in free faecal water indicates an abnormality in the colonic mucosa, even in the absence of conventional signs of inflammation. We could not confirm the hypothesis that sulphasalazine and 5-aminosalicylic acid exert their therapeutic effect through promotion of endogenous cytoprotective prostaglandins. In contrast, the observation that raised PGE2 concentrations were normalised by disodium azodisalicylate in patients with inactive ulcerative colitis suggests that subclinical disease activity was decreased by 5-aminosalicylic acid.

Adult↗
PubMed1981

Electron microscopic study of the regeneration in vitro of rat peritoneal mast cells after histamine secretion.

Regeneration of rat mast cells was studied by TEM from 10 s to 48 h after secretion of histamine induced by compound 48/80. During the first 2 h, small intracellular cavities, formed during compound exocytosis and containing non-membrane-bound remnants of the granules, tended to coalesce, and after 2 h of incubation regeneration started. After 6 h, all the cavities had fused into one large central cavity which contained the remnants of the granules and remained open to the exterior during the entire period. The plasma membrane microfolds which disappeared just after secretion were reformed during regeneration. They were apparently involved in endocytotic-like activity and coated vesicles also appeared beneath the plasmalemma (membrane recycling?). The fate of the granule remnants in the cavity is unknown, as regeneration was not completed after 48 h which is the longest survival time obtained so far in ultrastructural studies of mast cell regeneration in vitro.

Animals↗
PubMed1981

Surface morphology of rat peritoneal mast cells during in vitro regeneration after histamine secretion.

Cell-surface morphology of regenerating mast cells was followed over a period of 48 h after histamine release. Control cells (not stimulated to secrete) were characterized by anastomosing folds of membrane of equal depth and width. During exocytosis these folds disappeared and were replaced by deep cup-shaped flaps of membrane evident in cells incubated for 10 min. During the first hours of regeneration these flaps fused mutually or with the plasma membrane. This activity suggests membrane retrieval, maybe specifically recycling the granule-type patches of membrane. Membrane-fusion activity was observed to some degree also after extended incubation. After 48 h of incubation the regeneration process was still not completed, as indicated by the fact that holes leading to intracellular cavities could still be found.

Animals↗
PubMed1979

Scanning electron microscopy of Purkinje fibres of the pig heart.

Scanning electron microscopy (SEM) of Purkinje fibres (P-fibres) from the septal walls and the septomarginal trabecula was performed on deparaffinized sections, the identification in SEM made possible by comparative light microscopy. The myofibrils in P-fibres from the septal walls were arranged in a cart-wheel fashion, whereas P-fibres from the septomarginal trabecula showed a nearly parallel alignment of the contractile material. Z-line ridges resembling the T-tubules of the myocardial fibres were observed in both kinds of P-fibres. The myofibrillar arrangements are discussed in relation to the expected mechanical stress put upon P-fibres in the 2 locations during systolic-diastolic activity. An adaptive function of the contractile material to the mechanical stress is suggested and the possible need of a T-tubular system is discussed.

Animals↗
PubMed1979

High resolution scanning electron microscopy of elastic cartilage.

The elastic cartilage of the rat epiglottis was studied with a high-resolution SEM technique. The chondrocytes were found to be anchored in their lacunae by fibrils running in from the territorial matrix. This matrix exhibited a dense network of fibrils arranged tangentially around the lacunar cavity. The fibrils of the inter-territorial matrix however, formed a three dimensional network of sheets with interconnecting fibrils. The SEM has shown up for the first time a substructure in the fibrils in the form of circular protuberances arranged circumferentially around the fibrils and forming ridges 12--19 nm apart. We suggest that the fibrils are collagen, and the protuberances are the proteoglycans attached to the collagen fibrils. Globules seen attached to the fibrils are most probably 'matrix granules' as observed in other kinds of cartilage. The total inability to visualize elastin with the high resolution SEM is puzzling.

Animals↗