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Biomedical subjects

G M Murphy

Publications and source records attributed to G M Murphy.

At least 199 records · Page 11Linked to original sources
PubMed1990

Role of polyamines in the early adaptive response to jejunectomy in the rat: effect of DFMO on the ileal villus:crypt axis.

To study the role of the polyamines putrescine, spermidine and spermine and of the enzymes controlling their synthesis (ornithine decarboxylase; ODC) and degradation (diamine oxidase; DAO) along the villus:crypt axis at the crucial early stage of the ileal adaptive response to jejunectomy, we measured polyamine concentrations and the activities of ODC, DAO and alkaline phosphatase (a marker of enterocyte maturity) in epithelial cells isolated by the Weiser technique from villus tips, mid villi, lower villi and crypts 4 days after surgery in transected control (TRC) and jejunectomised rats untreated or given the specific ODC blocker, alpha-difluoromethyl ornithine (DFMO, 2% in drinking water beginning 3 days before surgery). In the TRCs, there was a diminishing villus tip-to-crypt gradient not only in alkaline phosphatase but also in ODC and DAO activities. After jejunectomy, there were up to 93% increases in mean enterocyte ODC activity when compared with the corresponding cell fractions from the TRCs, but in both the control and jejunectomised rats, DFMO treatment markedly inhibited ODC activity (p less than 0.05-0.01) and reduced spermidine and particularly putrescine concentrations (p less than 0.005-0.001) in all four cell fractions. Only 4 days post-operation, jejunectomy stimulated a significant increase in ileal wet weight but DFMO treatment completely prevented this adaptive response and significantly reduced segmental intestinal weight (mg/cm) in the TRCs. These results (i) extend our knowledge of polyamines and related enzymes along the villus:crypt gradient in the normal intestine, (ii) provides the first data on these variables after resection, and (iii) lend further support to the hypothesis that changes in enterocyte ODC activity and in putrescine and spermidine concentrations play an important role in initiating the ileal adaptive response to proximal small bowel resection in the rat.

Adaptation, Physiological↗
PubMed1990

Effect of fasting and feeding on polyamines and related enzymes along the villus: crypt axis.

Fasting and feeding have profound effects on crypt cell production and small bowel mucosal growth but the mechanism whereby food stimulates villus tip enterocytes to influence crypt cell production is unknown. We therefore measured the activities of ornithine decarboxylase (ODC), diamine oxidase (DAO) and alkaline phosphatase (ALP--a marker of enterocyte maturity) and polyamine concentrations in epithelial cells from villus tips, mid villi, lower villi and crypts of small intestine in non-fasted controls and 18-24 h fasted rats. Fasting reduced crypt cell production and caused villus hyperplasia, DAO activity (mU/g) increased in control villus tips from 9.6 +/- (SEM) 0.8 to 12.3 +/- 1.5 after fasting (NS), from 7.6 +/- 0.4 to 13.9 +/- 3.0 in mid villi (p less than 0.01), from 5.7 +/- 1.0 to 10.4 +/- 7.4 in lower villi (p less than 0.01) and from 5.4 +/- 0.9 to 12.8 +/- 1.5 in the crypts (p less than 0.001). ALP showed a similar pattern of results. In contrast, fasting lowered ODC activity (pmol/mg protein/h) dramatically from 319 +/- 82 in control villus tips to 16.7 +/- 3.0 during fasting, from 297 +/- 59 to 10.7 +/- 3.6 in mid villi, from 224 +/- 45 to 6.3 +/- 2.8 in lower villi and from 150 +/- 31 to 5.8 +/- 3.3 in the crypts. Fasting reduced putrescine concentrations in all fractions but particularly in the crypts and in general was associated with increases in spermidine and spermine concentrations. The role of DAO in the maintenance of low putrescine concentrations during fasting is unclear.

Alkaline Phosphatase↗
PubMed1990

Is the intestine the sole source of heparin-stimulated plasma diamine oxidase? Acute effects of jejunectomy, ileectomy and total enterectomy.

The assumption that the intestine is the sole/major source of post-heparin diamine oxidase (DAO) has been tested only once by Kobayashi et al. in 1969. In this study we tested whether the intestine is indeed the sole/major source of post-heparin plasma DAO and furthermore we studied the relative contribution of jejunum and ileum to post-heparin plasma DAO. We measured non-fasting plasma DAO before and every 15 min for 2 h after i.v. heparin (4,000 U/kg BW) and compared the resultant areas under the concentration-time curves (AUCs: mU/l X 2 h) in unoperated controls, jejunectomised, ileectomised and totally enterectomised (from gastro-oesophageal to colorectal junctions) male Wistar rats. Total enterectomy virtually abolished the post-heparin rise in plasma DAO, the mean AUC falling from 55.3 +/- (SEM) 10.2 in controls to 2.1 +/- 1.1 after enterectomy (p less than 0.001). The mean AUCs after jejunectomy and ileectomy were 25.6 +/- 5.5 and 10.75 +/- 2.42, respectively. Therefore in acute jejunal and ileal resection the AUCs were 2.1 and 5.4 times, respectively, lower than those seen in the controls (p less than 0.02 and p less than 0.001). The difference in mean AUC values between jejunectomy and ileectomy groups was also statistically significant (p less than 0.05). We conclude that total enterectomy abolishes the post-heparin rise in circulating DAO activity, confirming that the intestine is the major source of post-heparin plasma DAO. The ileum contributes more than the jejunum to this post-heparin rise in plasma enzyme activity.

Amine Oxidase (Copper-Containing)↗
PubMed1990

Aminoguanidine blocks intestinal diamine oxidase (DAO) activity and enhances the intestinal adaptive response to resection in the rat.

The aim of this study was to assess the effect inhibiting diamine oxidase (DAO) activity on intestinal adaptation after 80% proximal small bowel resection in the rat. Aminoguanidine (AG), a DAO inhibitor, was administered subcutaneously (25 mg kg-1 day-1) to rats for 11 days after small bowel transection (n = 6) or resection (n = 6). Two additional groups of animals (n = 6) served as transection or resection controls and received normal saline subcutaneously for the same period. On day 12 after operation, the animals were sacrificed, mucosal homogenates prepared from the ileal remnants (or from the control ileum), analysed for DAO and ornithine decarboxylase (ODC) activities, and the concentrations of the polyamines putrescine, spermidine, spermine, and the indices of mucosal mass (wet weight, protein and DNA) measured. The results were expressed both per unit length intestine and per milligram mucosal DNA. AG treatment completely inhibited DAO activity in both the transection control and resected rats. In the AG-treated resection group, inhibition of DAO activity was accompanied by increases (p less than 0.005) in all three indices of mucosal mass (wet weight, protein and DNA per centimetre intestine), putrescine concentrations (p less than 0.05) and ODC activity per centimetre intestine (p less than 0.001) when compared with the saline-treated resection controls. The results of this study suggest that inhibition of the putrescine-degrading enzyme, DAO, enhances the adaptive response to intestinal resection. Therefore, DAO may play a major role in regulating adaptive intestinal mucosal growth. Furthermore, inhibition of DAO activity could be important therapeutically in patients with the short bowel syndrome.

Adaptation, Physiological↗
PubMed1990

Calcium binding by bile acids: in vitro studies using a calcium ion electrode.

In this study, we compared in vitro calcium binding by the taurine and glycine conjugates of the major bile acids in human bile: cholic (CA), chenodeoxycholic (CDCA) and deoxycholic (DCA) acids, together with the cholelitholytic bile acids ursodeoxycholic (UDCA) and ursocholic (UCA) acids. At physiological total calcium (CaTOT) (1-15 mM) and bile acid (BA) (10-50 mM) concentrations, all the bile acids caused concentration-dependent falls in [Ca2+], suggesting calcium binding. Except for glycine-conjugated CDCA, all the other calcium-bile acid complexes were soluble in 150 mM NaCl. The calcium binding affinities followed the pattern: dihydroxy (CDCA, UDCA and DCA) greater than trihydroxy (CA and UCA) bile acids, and glycine conjugates greater than taurine conjugates. The glycine conjugate of UDCA, which increases during UDCA treatment, had the highest calcium binding affinity. Ten-20 mM phospholipid modestly increased calcium binding by CA conjugates, but not by CDCA, UDCA, and DCA conjugates. Phospholipid also prevented the precipitation of glyco-CDCA in the presence of calcium. Bile acid-calcium biding was pH-independent over the range 6.5-8.5. The different calcium binding affinities of the major biliary bile acids may partly explain their varying effects on biliary calcium secretion. The results also suggest that neither precipitation of calcium-bile acid complexes nor impaired calcium binding by bile acids is important in the pathogenesis of human calcium gallstone formation.

Alkanesulfonates↗
PubMed1990

Final outcome of ursodeoxycholic acid treatment in 126 patients with radiolucent gallstones.

One hundred and twenty-six patients with radiolucent gallstones in 'functioning' gallbladders were treated with 8-10 mg ursodeoxycholic acid (UDCA) kg/day and followed to a treatment conclusion. Complete or partial gallstone dissolution was achieved in 74 (59 per cent). However, only 22 achieved complete gallstone dissolution, as judged by two normal oral cholecystograms; ultrasonograms were performed in 16 of these patients, and all were normal. UDCA was stopped in 76 patients: because of cystic duct obstruction (n = 12), severe biliary pain (n = 13), non-response (n = 25) or partial stone dissolution with arrested progress (n = 26). Life-table analysis showed that complete gallstone dissolution rates at four years were 25-30 per cent (two normal oral cholecystograms) and 17-19 per cent (two normal oral cholecystograms plus one ultrasonogram). All patients with complete gallstone dissolution had shown partial stone dissolution at 6-12 months; of those with partial stone dissolution at six months, only 25 per cent went on to complete gallstone dissolution, and then always within two years. Efficacy correlated inversely with stone size but not with age, sex, obesity or on-treatment saturation indices. Acquired surface gallstone calcification developed in 13 patients (life-table analysis 22 +/- 7 per cent at four years); none of these patients achieved complete gallstone dissolution and only five achieved partial stone dissolution. Thus, despite relatively high partial gallstone dissolution rates, the ultimate efficacy of UDCA in achieving complete gallstone dissolution is low.

Adult↗
PubMed1989

Cholestasis of total parenteral nutrition: bile acid and bile lipid metabolism in parenterally nourished rats.

As food in the intestine "drives" the enterohepatic circulation and bile acids influence bile flow, we postulated that the cholestasis of total parenteral nutrition might be due to bile acid changes, and the cholelithiasis and biliary sludge of total parenteral nutrition to bile lipid changes. We therefore studied bile acid and bile lipid metabolism in the following groups of rats, with and without bile fistula: (a) nonfasted, orally fed controls, (b) orally fed controls fasted for 20 h, and (c) after 7 days of total parenteral nutrition. Biliary bile acid concentration (35.4 +/- 2.5 mM) and secretion (253 +/- 20.0 mumol/100 g body wt.24 h) increased significantly in the rats on TPN and the rats fasted for 20 h (38.8 +/- 2.5 and 243 +/- 23.4 mM, respectively) when compared with the orally fed controls (26.5 +/- 2.5 and 178 +/- 23.5 mM, respectively). Bile flow, however, was unchanged. Bile acid pool size (Eriksson washout technique) also increased from 43.4 +/- 3.0 mumol/100 g body wt in the controls to 50.5 +/- 4.8 in the group fasted for 20 h and 65.6 +/- 5.3 in the TPN group (p less than 0.05-0.01). Similar bile acid pool sizes (carcass extraction method) were found in the nonfistulated animals. Biliary cholesterol secretion and saturation were significantly less in the TPN rats than in the other two groups. Liver microscopy indicated only minimal fatty change, but serum bile acid and alkaline phosphatase levels were increased in the TPN group (p less than 0.05). Thus, during TPN bile acids stagnate within the enterohepatic circulation, increasing biliary bile acid concentration and secretion rates and expanding the pool size. However, the absence of an associated choleresis, together with abnormal liver function tests, suggest that alterations in bile acid metabolism cause a relative cholestasis in this model.

Animals↗
PubMed1989

A comparison of the proinflammatory effects of 12(R)- and 12(S)-hydroxy-5,8,10,14-eicosatetraenoic acid in human skin.

Topical application of racemic 12-hydroxy-5,8,10,14-eicosatetraenoic acid [12(R,S)-HETE] produces erythema and leucocyte accumulation in human skin. Since 12(R)-HETE is more potent than its epimer 12(S)-HETE as a neutrophil chemoattractant in vitro, their proinflammatory effects have now been compared in vivo. 12(R)- and 12(S)-HETE (0.5 - 20 ug/site) were applied topically to the forearm skin of 5 healthy volunteers and the sites occluded for 6 h. Five ug each of the two enantiomers were also applied to the opposite forearm. At 6 and 24 h blood flow and the areas of erythematous responses were measured. The 5 ug application sites were biopsied at 24 h. Both enantiomers caused dose related erythema and increased blood flow at 6 and 24 h, which were not significantly different at either of the time points tested. In contrast, pronounced neutrophil infiltrates were seen in the epidermis (25.2 +/- 13 cells/hpf) and dermis (13.2 +/- 5.1 cells/hpf) 24 h after application of 12(R)-, but not 12(S)-HETE (0.02 +/- 0.02 and 1.02 +/- 0.7 cells/hpf in epidermis and dermis respectively). However, the numbers of dermal mononuclear cells accumulating in response to the two enantiomers were similar. 12(R)-HETE thus appears to be a more potent neutrophil chemoattractant than 12(S)-HETE in human skin in vivo and may be of potential importance as a mediator of inflammation in man.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1989

Evidence for eosinophil degranulation with deposition of granule major basic protein in solar urticaria.

Multiple sequential biopsy specimens of wheals elicited by a solar simulator in four patients with severe solar urticaria were studied with the use of indirect immunofluorescence for eosinophil granule major basic protein. Examination of control biopsy specimens from normal, unstimulated skin did not show eosinophils or major basic protein deposition. Five minutes after solar simulation, eosinophils were observed in vessels in the dermis, and 2 hours later there was marked tissue eosinophilia. Extracellular major basic protein was extensively deposited in the dermis at 2 and 24 hours, suggesting eosinophil degranulation. Thus evolution of the solar urticaria wheal is accompanied by infiltration of eosinophils and neutrophils and by tissue deposition of the eosinophil major basic protein, suggesting eosinophil degranulation.

Blood Proteins↗
PubMed1989

Sunbed-induced pseudoporphyria.

The clinical details of four fair-skinned women with recurrent blistering and skin fragility are presented. All had considerable sun-exposure and had used sunbeds for years. Specific causes of bullous dermatoses including drug ingestion, porphyria, cutaneous amyloidosis and epidermolysis bullosa acquisita were excluded. Long-term recurrent exposure to high doses of sunbed radiation in chronically sun-damaged skin appears to be a further cause of pseudoporphyria.

Adult↗
PubMed1989

UVA sunbeds: tanning, photoprotection, acute adverse effects and immunological changes.

The effects on 31 normal subjects following exposure to sunbeds containing UVA lamps with minimal UVB emission have been compared in a double-blind study with the effects on nine control subjects of a similar exposure course three times weekly for 4 weeks to sunbeds emitting visible light. On previously untanned areas, all those subjects on active treatment developed a mild tan; in tanned areas they all developed a moderate tan, while all control subjects developed a minimal to mild tan. The mean protection factor against later UVB-induced erythema was 3.2 +/- 0.3 after the active course and 1.6 +/- 0.2 among the controls. Significantly more frequent adverse cutaneous effects for active subjects were pruritus, erythema, freckling, burning sensation, dryness and polymorphic light eruption. Cutaneous Langerhans cell numbers, and blood CD3+ (pan T-cell) and CD4+ (helper T-cell) lymphocyte subsets were reduced in both active and control groups. CD8+ (cytotoxic/suppressor T-cell) counts were similarly but not significantly reduced in both groups. Pityrosporum yeast counts were significantly reduced in both groups. The changes found in both groups seem attributable to small amounts of UVB emission from both active and control lamps.

Adolescent↗
PubMed1989

Azathioprine treatment in chronic actinic dermatitis: a double-blind controlled trial with monitoring of exposure to ultraviolet radiation.

Oral azathioprine was compared with placebo in a double-blind controlled trial of therapy in chronic actinic dermatitis (CAD), a rare eczematous photodermatosis. Eighteen severely affected patients were randomly allocated to azathioprine 50 mg t.d.s. or placebo over a 2-year period. Severity of itch and rash were assessed weekly by each patient on a visual analogue scale and overall clinical status monthly by a medical observer. Monitoring of patient ultraviolet radiation (UVR) exposure was undertaken throughout treatment by polysulphone film lapel-badge dosimetry. Five of 8 patients treated with azathioprine but none of 10 placebo patients achieved remission within 6 months. One patient could not tolerate treatment because of gastrointestinal effects. No haematological or hepatic abnormality was noted. The marked improvement in clinical status of actively treated patients (P less than 0.02, Fisher's exact test), led to early termination of the trial. Oral azathioprine therapy is an effective and usually well tolerated treatment in chronic actinic dermatitis.

Aged↗
PubMed1989

Subcorneal pustular dermatosis.

Subcorneal pustular dermatosis (SCPD) (Sneddon-Wilkinson disease) is a rare disorder. We present a case with classical clinical manifestations, and discuss the management of this disorder.

Aged↗
PubMed1989

Lichen planus pemphigoides.

Lichen planus pemphigoides is a rare disease in which blistering occurs in association with lesions of classical lichen planus. We describe a patient with lichen planus pemphigoides and discuss the evidence for there being one disease rather than the coincidence of bullous pemphigoid and lichen planus.

Adult↗
PubMed1989

Aphthous ulcers responding to etretinate--a case report.

Aphthous ulcers are notoriously difficult to treat. We report repeated remission of recurrent aphthous ulceration in a female while taking etretinate for plantar pustular psoriasis. Although systemic retinoids are potent teratogens and are generally inappropriate for women of childbearing potential, this case report suggests further assessment of retinoids in severe aphthosis is warranted in selected patients.

Adult↗
PubMed1989

Ursocholic acid: bile acid and bile lipid dose response and clinical studies in patients with gall stones.

The biliary bile acid and bile lipid responses to six weeks treatment with approximately 5, 10, and 15 mg/kg/day of ursocholic acid (UCA) were studied in 11 gall stone patients. Maximum enrichment of bile with UCA (24 (SE) 4.9%) occurred with 15 mg UCA/kg/day. The maximum reduction in biliary cholesterol saturation was seen with the 10 mg/kg/day dose when the moles % cholesterol fell from 14 (2.4)% before treatment to 5.6 (0.83)% (p less than 0.02) and the saturation index fell from 1.4 (0.23) to 0.77 (0.13) (p less than 0.05). Clinical studies of the safety and efficacy of UCA in dissolving gall stones were carried out in 13 patients treated for up to two years with a dose of approximately 10 mg/kg/day. Diarrhoea caused withdrawal of treatment in three patients. There were no significant changes in liver function or haematology tests but fasting serum cholesterol tended to rise during treatment. Of nine patients treated for greater than 6 months, only one showed complete gall stone dissolution. As UCA may cause diarrhoea and hypercholesterolaemia, has only a modest effect on biliary cholesterol saturation and low gall stone dissolution efficacy, it is unlikely to replace existing forms of gall stone dissolution therapy.

Aged↗