Biomedical subjects

B J Danesh

Publications and source records attributed to B J Danesh.

28 records · Page 2Linked to original sources

PubMed1987

Is an acid pH medium required for the protective effect of sucralfate against mucosal injury?

It has been suggested that an acidic medium is required for the action of sucralfate in providing mucosal protection. We have examined the effect of sucralfate (300 mg/kg) at an acidic pH of 1.5 and a near-neutral pH of 6.5 on the occurrence of mucosal damage induced in rats by aspirin alone and aspirin combined with bile acids. Fasting Sprague-Dawley rats received test solutions by oral intubation, and their stomachs were examined four hours later for the presence of hemorrhagic erosions. Sucralfate significantly reduced mucosal erosions induced by aspirin alone and aspirin combined with bile acids at pHs of both 1.5 and 6.5. These results indicate that the protective effect of sucralfate against mucosal injury induced by aspirin and bile acids is not dependent on an acidic medium.

Animals↗

PubMed1987

Angiodysplasia--an uncommon cause of colonic bleeding: colonoscopic evaluation of 1,050 patients with rectal bleeding and anaemia.

Angiodysplasia of the colon was diagnosed in 31 out of 1,050 patients (3%) presenting with rectal bleeding or anaemia, among 10,000 colonoscoped at St. Mark's Hospital. The lesions were identified in 16 out of 879 (2%) patients with rectal bleeding, in 15 out of 171 (9%) patients with anaemia, and in a further three patients without features of blood loss. The angiodysplasia lesions were predominantly in the right colon (76%) and occurred with a similar frequency (12%) in the transverse and the left colon. Affected patients (59% male and 41% female) were in the older age group (53-89 years; mean age 69.5 years) but only one patient had known aortic valve disease. Angiodysplasia is an important diagnosis to consider in patients presenting with colonic bleeding or anaemia because it can be treated in the majority of cases by endoscopic electrocoagulation. However in our experience it is less common (3%) than previously suggested by other authors (40-67%). Endoscopic over-diagnosis is possible when intramucosal capillaries with no bleeding tendency on local traumatisation or biopsy are included in the diagnosis but these lesions are not true angiodysplasia.

Aged↗

PubMed1987

Replacing the acetyl linkage in aspirin with choline and magnesium moieties reduces the occurrence of gastric mucosal injury.

The acetyl moiety in aspirin (acetyl salicylic acid: ASA) is considered to play a major part in the pathogenesis of ASA-induced mucosal injury. At equivalent salicylate doses and pH values, the induction of acute gastric mucosal haemorrhagic erosions in rats by ASA and choline magnesium trisalicylate (CMT), a new non-acetylated salicylate, with and without the potentiating damaging effect of taurodeoxycholic acid (TDCA) were compared. Test solutions were administered by per oral intubation to five groups of fasting Sprague-Dawley rats (n = 24). Gastric mucosa were examined after 4 hours and mucosal injury assessed by a lesion-scoring system. The incidence and severity (median lesion scores with quartiles) of the lesions were 83% and 13 (7:20) respectively for ASA (128 mg kg-1) compared with 17% and 0 (0:0) for CMT (128 mg kg-1) (P less than 0.001 and P less than 0.001). TDCA increased mucosal damage to 100% and 29 (20:34) for ASA compared with 30% and 0 (0:4) for CMT (P less than 0.001) and P less than 0.001). Serum salicylate levels (median values of 1.4 for ASA and 1.5 mmol litre-1 for CMT) were not significantly different. It is concluded that replacing the acetyl moiety in ASA with choline and magnesium moieties reduces the ASA-induced mucosal injury, without affecting blood salicylate concentrations.

Animals↗

PubMed1987

Therapeutic potential of choline magnesium trisalicylate as an alternative to aspirin for patients with bleeding tendencies.

We have compared the effects of acetyl salicylic acid (ASA, aspirin) and choline magnesium trisalicylate (CMT), a non-acetylated salicylate product, on platelet aggregation in human whole blood ex-vivo. Using a whole blood platelet counter, platelet aggregation was quantified by measuring the fall in the number of single platelets at peak aggregation in response to collagen, arachidonic acid (AA), as well as spontaneous aggregation. In double blind and random order, 12 healthy volunteers received, on two separate occasions 10 days apart, a single oral dose of 652 mg ASA or 655 mg CMT. Despite a comparable absorption of salicylic acid from the two drugs, ingestion of ASA resulted in a marked inhibition of platelet aggregation induced by collagen (p less than 0.005), AA (p less than 0.01) and spontaneous aggregation (p less than 0.01), whereas such effects were not observed after CMT ingestion. We suggest that CMT may have therapeutic potential as an alternative to aspirin when inhibition of platelet aggregation can induce bleeding complications.

Adolescent↗

PubMed1985

Comparison of weight, depth, and diagnostic adequacy of specimens obtained with 16 different biopsy forceps designed for upper gastrointestinal endoscopy.

The influence of endoscopic forceps variables (size, design, and make) on biopsy specimen weight, depth, and diagnostic adequacy has been studied in vitro on normal human stomach, and in vivo at endoscopy in dog and in patients. Greater pressure during the biopsy procedure yielded significantly heavier, deeper, and histologically more acceptable specimens. Standard sized forceps (diameter 2.4 mm) and those with ellipsoid cups consistently produced larger specimens than the smaller 'paediatric' forceps (1.8 mm) and those with round cups. Deeper specimens were also obtained using the standard forceps. In vitro and in vivo in the dog, the standard sized forceps also produced specimens of greater diagnostic adequacy than the paediatric forceps. At endoscopy in patients, however, we could not detect any influence of the size, shape, and presence of forceps spike or fenestration on the diagnostic adequacy of the specimens.

Animals↗

PubMed1984

Comparison between short-term renal haemodynamic effects of propranolol and nadolol in essential hypertension: a cross-over study.

The effect of 4-6 weeks' treatment with propranolol and nadolol on effective renal plasma flow (ERPF) and glomerular filtration rate (GFR) was studied, in 14 patients with essential hypertension, in single blind, random and cross-over design. Both drugs caused comparable effective lowering of pulse and blood pressure. When taken as the first drug, propranolol caused significant reduction in ERPF and GFR and a rise in filtration fraction (FF) and renal vascular resistance (RVR), whereas nadolol caused distinct rise in ERPF and a fall in FF and RVR but GFR remained unchanged. These haemodynamic effects were reduced when propranolol was given immediately after the withdrawal of nadolol and were obviated when nadolol followed propranolol therapy. This suggested a carry-over effect of the first drug into the second phase of treatment. We conclude that with short term therapy in essential hypertension, propranolol has a renal vasoconstrictor and nadolol a vasodilator effect.

Adrenergic beta-Antagonists↗

PubMed1973