Opioid needs of terminal care patients: variations with age and primary site

The records of 1383, terminal cancer patients have been reviewed to determine whether opioid requirements vary in a consistent pattern with age and with site of primary cancer. Opioid requirements are shown to decrease with age in a regular pattern and from early adult life. Opioid requirements also differ significantly with site of primary cancer and there appears to be a discernible pattern of opioid need for different cancers. Patients with sexually related cancer have the highest opioid requirements, irrespective of sex. When the sexually determined cancers are excluded, the analgesic needs of men and women are not significantly different (P = 0.191).

Effect of bismuth subcitrate and sucralfate on rat duodenal and human gastric bicarbonate secretion in vivo

Acid and alkali secretion have been examined together with prostaglandin E2 production in response to two mucosal protective drugs, colloidal bismuth subcitrate and sucralfate. Doses of colloidal bismuth subcitrate in the therapeutic range (120 and 1200 mg) had no effect on alkali secretion or luminal PGE2 output when perfused into the stomach of human volunteers. Similarly, in the anaesthetised rat, neither gastric acid nor duodenal alkali secretions were influenced by iv (12 mg/kg) or topical (120 mg/ml) administration of colloidal bismuth subcitrate. In contrast, perfusion of the human stomach with 1 g sucralfate stimulated bicarbonate output by 50%, a response which was unaffected by indomethacin (25 mg/h). A rise of 64% in gastric PGE2 output after sucralfate was, however, prevented by indomethacin pretreatment. Alkali secretion by rat duodenum was also increased by sucralfate but the response depended on the basal secretory rate. Low basal secretors (less than 3 mumol) showed a 75% stimulation whereas rats with high basal secretory rates (greater than 3 mumol) showed no significant response. All duodenal preparations regardless of basal secretory rate showed a stimulation of bicarbonate output with topical PGE2. The results suggest that enhancement of gastroduodenal bicarbonate secretion may play a role in the protective action of sucralfate but is unlikely to explain mucosal protection by colloidal bismuth subcitrate.

Effect of enprostil on amphibian gastroduodenal and human gastric bicarbonate secretion

The protective and ulcer healing properties of prostaglandins are well established. We have explored the possible mode of action of enprostil, a synthetic dehydroprostaglandin E2, on amphibian gastroduodenal mucosal bicarbonate secretion in vitro and on human gastric bicarbonate secretion in vivo. Addition of enprostil (10(-6) M) to the luminal solution of isolated amphibian gastric mucosa produced a 28% increase in bicarbonate secretion without a change in transmucosal potential difference. The same concentration of enprostil added to the luminal solution of isolated amphibian duodenal mucosa produced a 37% increase in bicarbonate secretion and was associated with a rise in transmucosal potential difference. The gastric output of bicarbonate from the human stomach has been calculated using a perfusion technique before, during, and after perfusion with enprostil (35 micrograms) in six healthy volunteers. A significant 78% increase in bicarbonate secretion occurred during the period of enprostil perfusion, falling to normal during the postenprostil period. These changes were caused mainly by an increase in gastric secretory volume with insignificant increases in bicarbonate concentration. These results suggest that stimulation of gastroduodenal bicarbonate secretion by enprostil may play a role in its protective actions.

Effect of bismuth subcitrate on amphibian gastroduodenal bicarbonate secretion

The ulcer healing and cytoprotective properties of colloidal bismuth (De-Nol) are well established although its mode of action is unclear. We have examined the action of bismuth subcitrate, the active ingredient of De-Nol, on gastroduodenal bicarbonate secretion by isolated amphibian mucosa. Addition of bismuth subcitrate (10(-6) to 10(-4) M) to the luminal solution produced a dose dependent increase in bicarbonate secretion from both gastric and duodenal mucosae without a change in transmucosal potential difference. The magnitude of this stimulation was greater for gastric than duodenal mucosae at all dose ranges. A second bismuth salt, bismuth oxynitrate, produced similar increases in bicarbonate secretion from gastric mucosae. Pretreatment of gastric mucosa with the cyclooxygenase inhibitor, indomethacin (10(-5) and 10(-4) M), did not abolish the secretory response to bismuth subcitrate. Similar treatment with the chloride transport inhibitor, 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS) (10(-3) M) prevented the secretory response to bismuth subcitrate.

Effect of sucralfate on human gastric bicarbonate secretion and local prostaglandin E2 metabolism

The protective and ulcer-healing properties of sucralfate on gastroduodenal mucosa are well established. In this study, the possible mode of action of sucralfate in humans has been explored by examining its effect on gastric bicarbonate secretion and luminal prostaglandin E2 (PGE2) output from the intact stomach. The gastric output of bicarbonate and PGE2 has been calculated using a perfusion technique before, during, and after perfusion with sucralfate (8 mg/ml) in eight healthy volunteers. A significant increase in bicarbonate output occurred during the period of sucralfate perfusion returning to basal values during the post-sucralfate period. Pretreatment with indomethacin (25 mg/hour) failed to influence this secretory response. Luminal PGE2 output was significantly increased in the post-sucralfate perfusion period only. These changes were caused mainly by an increase in gastric secretory volume with insignificant increases in concentrations of bicarbonate and PGE2. These results suggest that stimulation of gastric bicarbonate secretion and PGE2 output by sucralfate may play a role in its protective actions.

Oesophageal ulcer caused by warfarin

Oesophageal injury is a well recognized complication of certain oral medications but warfarin has not been implicated previously. We present a case of an oesophageal ulcer occurring in a patient with mitral regurgitation taking warfarin, and demonstrate a delayed oesophageal tablet transit time.

Mechanisms of gastric damage by non-steroidal anti-inflammatory drugs

All non-steroidal anti-inflammatory drugs (NSAIDs) used in the treatment of rheumatic diseases may cause gastrointestinal mucosal injury. The mechanisms by which these agents damage mucosa are not fully understood, although, reduction of mucosal defence by the depletion of endogenous, protective prostaglandins has been deemed important. NSAIDs have been shown to decrease the magnitude of the mucus-bicarbonate barrier, disrupt the epithelial cell layer, reduce the surface hydrophobicity of epithelial cells and to diminish mucosal blood flow. Such effects render the mucosa more susceptible to damage by acid, pepsin, bile salts and alcohol. In addition, direct mucosal injury may be caused by the physiochemical properties of NSAIDs, being weak acids. There is now increasing evidence that gastroduodenal mucosa adapts to acute damage by these drugs with mucosal injury recovering during continued administration. The mechanisms governing such adaptation remain unknown and require further investigation.

Stimulation of amphibian gastroduodenal bicarbonate secretion by sucralfate and aluminium: role of local prostaglandin metabolism

The present studies were designed to explore the possible mode of protective and ulcer healing actions of sucralfate by examining its effect on gastroduodenal bicarbonate secretion by isolated amphibian mucosa. Luminal sucralfate (0.5 g/l) significantly increased bicarbonate secretion by fundic and antral mucosa without influencing transmucosal potential difference. Significant stimulation of duodenal bicarbonate secretion occurred only at 1.0 g/l without change in potential difference. Aluminium, a component of sucralfate, produced similar increases in bicarbonate secretion, while the sucrose and sulphate components were without effect. Pretreatment of mucosae with the cyclooxygenase inhibitor, indomethacin (10 5M) did not abolish the secretory response to sucralfate or aluminium. The results suggest that stimulation of gastroduodenal bicarbonate secretion, possibly by the aluminium moiety of sucralfate, may play a role in its protective and ulcer healing actions.

Overview of gastroduodenal mucosal protection

The ability of the gastric mucosa to resist autodigestion has been recognized for over 200 years. Since these early observations, several components of gastroduodenal defense against injury from damaging luminal contents have been identified. The first line of defense is the thick layer of mucus gel into which bicarbonate is secreted by the underlying epithelial cells. The "mucus-bicarbonate" barrier sustains a pH gradient between the lumen and cell surface such that epithelial cells are maintained at pH 7 to 8, despite the presence of intraluminal acid. The epithelial cells form a second line of defense; since the pH gradient may be overwhelmed by physiologic concentrations of intraluminal acid, this mechanism may be important in maintaining mucosal integrity. The physical properties of the apical cell membrane and intercellular junctions and the presence of surface-active phospholipids on the membrane may be responsible for preventing hydrogen ions (H+) from diffusing into the mucosa by providing a physical barrier to their movement. Furthermore, epithelial cells are capable of rapid turnover and migration and may breach a defect in the epithelium within hours. The aftermath of mucosal damage may generate a further defense mechanism: a thick layer of mucus containing sloughed epithelial cells together with passive movement of bicarbonate-rich fluid from the damaged mucosa. This may prevent exposure of undamaged cell nests to acid and thus aid re-epithelialization. Finally, mucosal blood flow plays a vital role in maintaining epithelial integrity. Studies have shown that increasing or decreasing mucosal blood flow will, respectively, reduce or enhance susceptibility to damage. Although the precise physiologic control mechanisms for mucosal protection have not been defined, there is evidence that local endogenous prostaglandin metabolism may play an important role [4]. The release of neurotransmitters and hormones may also contribute to or modulate the defense mechanisms.

Neural regulation of duodenal alkali secretion: effects of electrical field stimulation

The role of transmitters released from enteric neurons in regulating bicarbonate secretion by the proximal duodenum has been studied using electrical field stimulation (EFS). Stripped duodenal mucosa from Rana catesbeiana was mounted as an intact tube over circular platinum electrodes, and luminal alkalinization was measured by pH stat titration before, during, and after EFS. Transmucosal potential difference (PD) was simultaneously measured before and after EFS by paired electrodes. Square-wave pulses 50 V, 2 ms in duration, at 10 Hz were delivered in trains of 0.5 s at 1 Hz for periods of 15 min after stable basal secretion. This resulted in a 63 +/- 27% increase in alkalinization that returned to basal values after cessation of the stimulus, without change in transmucosal PD. Serosal-to-lumen [3H]mannitol flux was not affected. Repetition of the stimulus resulted in similar responses for as long as the tissue remained viable. The response to EFS was abolished by tetrodotoxin (10(-6) M) and veratrine (0.1 mg/ml), indicating that intrinsic neurons were responsible for mediating the effect. In addition, the effect was blocked by serosal dinitrophenol (10(-4) M), indicating that the secretory response occurred by a metabolically dependent process. These results indicate that alkalinization by proximal duodenum may be controlled by neurotransmitter release from local enteric neurons.

Changes in prescribing for terminal care patients in general practice, hospital and hospice over a five-year period

Differences in prescribing between 1981 and 1986 were examined for 100 terminal care patients admitted to a city hospice in each year. Prescribing before and after the patients were admitted to the hospice was also compared for the two years. Between 1981 and 1986 there was a large increase in the number of patients receiving morphine sulphate tablets and a reduction in the numbers receiving Brompton's mixture and other unsuitable analgesics both before and after admission. Contrary to critical opinion, general practitioners showed more acceptable prescribing patterns in both years than hospital doctors. In the hospice more patients received non-narcotic analgesics and parenteral diamorphine by syringe driver in 1986 than in 1981. The need for an organized system of postgraduate training in terminal care is considered.

Effect of luminal pH on the output of bicarbonate and PGE2 by the normal human stomach

The gastric output of bicarbonate and prostaglandin E2 has been calculated using a perfusion technique before and after instillation of 100 mM hydrochloric acid into the stomach of seven healthy volunteers. A significant increase in bicarbonate output occurred from 258 +/- 38 mumol/30 min during the basal period to 531 +/- 86 mumol/30 min after return of the intragastric pH to neutral (p less than 0.05). Prostaglandin E2 output also increased significantly from 410 +/- 136 pmol/30 min to 1002 +/- 194 pmol/30 min (p less than 0.05). The changes were caused mainly by an increase in gastric secretory volume with only non-significant increases in concentrations of bicarbonate and prostaglandin E2. The results suggest that mechanisms exist to adjust the rate of gastric bicarbonate secretion to the prevailing intraluminal pH and that this may occur through the release of prostaglandin E2.

Binding of cytochalasin B to trypsin and thermolysin fragments of the human erythrocyte hexose transporter

The cleavage of the human erythrocyte hexose transporter by the proteinases trypsin and thermolysin has been studied. When red cell membranes are treated with trypsin, washed and then photolabelled with cytochalasin B, a labelled peak at 18 kDa is obtained. This labelling of the cleaved transporter is D-glucose inhibitable. This probably indicates that the residual 36 kDa portion of the transporter is not required for binding of ligands. Extensive cleavage of the transporter with low concentrations of thermolysin only occurs when transporter is prelabelled with cytochalasin B. This indicates that covalently bound cytochalasin B can cause a conformational change which exposes the thermolysin cleavage site.

Evaluation of the hydrogen breath test in man: definition and elimination of the early hydrogen peak

After ingestion of a non-absorbable carbohydrate breath hydrogen excretion increases early at about 10 minutes, and again later when the ingested carbohydrate enters the caecum. The late rise has been used as a marker of mouth to caecum transit time, but the source of the early rise has not been satisfactorily explained. We studied in 60 healthy volunteers the source and frequency of the early rise in breath hydrogen after ingestion of a non-absorbable carbohydrate. After ingestion of either lactulose solution (10 g in 150 ml water), lentil soup (46 g carbohydrate) or solid meal containing baked beans (15 g carbohydrate), breath hydrogen was significantly raised above basal concentrations within 10 minutes (81 +/- 27, 395 +/- 138 and 110 +/- 52% above basal respectively). A significant rise in breath hydrogen (75 +/- 21%) occurred 10 minutes after sham lactulose feeding (lactulose applied to oral cavity but not swallowed), but no early peak occurred after sham saccharin feeding (non-fermentable carbohydrate), intragastric or intraduodenal administration of lactulose. Ten of the 12 subjects given lactulose sham feeding were restudied after oral hygiene with chlorhexidine mouthwash. In these the early hydrogen peak was abolished. Oral hygiene also reduced the occurrence and magnitude of the early hydrogen rise after lactulose ingestion. These findings indicate that the early rise in breath hydrogen observed after ingestion of lactulose is produced by interaction with oral bacteria.

Simultaneous measurement of in vitro gastroduodenal prostaglandin E2 synthesis and degradation in peptic ulcer disease

The ability of mucosal specimens from the stomach and duodenum to synthesize and degrade prostaglandin E2 has been determined in normal subjects and peptic ulcer patients. Significant reduction in fundic PGE2 synthesis capacity was observed in gastric ulcer patients. There was also significant reduction in the PGE2 degradation capacity of antral, fundic, and duodenal mucosal specimens in gastric ulcer patients. Patients with gastritis showed significant elevation of both antral and fundic PGE2 synthesis capacity compared with normal but no alteration in PGE2 degradation. No differences were observed in PGE2 synthesis and degradation rates in patients with duodenal ulcer. The results argue in favour of an association between impairment of PGE2 metabolism in the mucosa of patients with gastric but not duodenal ulceration.

Effect of naloxone on the antral motor response to solid food in man

Antroduodenal motor activity was recorded in eight healthy subjects using perfused tubes connected to external strain gauge transducers. Each subject was studied over a 2.5-h period following ingestion of a solid meal, on 2 separate days. Intravenous saline was administered on one day and saline plus naloxone (40 micrograms kg-1 h-1) on the other, in randomized order. Naloxone markedly inhibited the antral motor response to food and this effect was due to decreased amplitude and contractile frequency. The duodenal motor response to solid food and the postprandial rise in serum gastrin and plasma pancreatic polypeptide were not altered by naloxone. These observations suggest that peripheral or central opiate receptors play a role in regulating the antral motor response to food.

Photolabelling of the hexose transporter at external and internal sites: fragmentation patterns and evidence for a conformational change

The human erythrocyte sugar transporter has been labelled at its internal site with cytochalasin B and at its outside site by the azidosalicoyl derivative of bis(D-mannose) (ASA-BMPA). The cleavage of the transporter by various proteinases has been studied. Chymotrypsin, subtilisin and V8 proteinase give parallel fragmentation patterns for the two labels down to fragments as small as 7 kDa. Thus the binding sites for the two labels can only be separated by a small span of protein. 2-Nitro-5-thiocyanobenzoic acid (NTCB) cleaves at cysteines to give a 15 kDa fragment from the two labels. N-Bromosuccinimide (a reagent which preferentially cleaves at tryptophan residues) has revealed differences in fragmentation of the transporter labelled with either cytochalasin B or with ASA-BMPA. A major cleavage site is proposed to occur at tryptophan 186 which leaves a C-terminal fragment containing both labels. A tryptophan cleavage at residue 388 divides the cytochalasin B site and the ASA-BMPA site. A further tryptophan cleavage gives a cytochalasin B labelled 3 kDa fragment probably from residues 388-412. This gives an assignment of the cytochalasin B site as the inside of the hydrophobic span H 10. Since the ASA-BMPA site is probably only 7 kDa from residue 388 and is on the same 15 kDa NTCB fragment as cytochalasin B we assign this to the outside of hydrophobic span H 9. Thermolysin only cleaves the transporter labelled with cytochalasin B and not with ASA-BMPA. A 18 kDa cytochalasin B labelled fragment is formed. This is indicative of a change in conformation of the transporter when an outside ligand is bound such that the inside of the hydrogen bonding transmembrane segments H 7 and H 8 (and containing the proposed thermolysin cleavage site) are withdrawn from the cytosolic surface. Thus it appears that the core of the transporter (including the external and internal sites plus the transmembrane channel) is located between segments H 7 and H 10.

Re-examination of hexose-transporter inhibition and labelling by hexose isothiocyanates

We have re-examined hexose-transport inhibition by hexose isothiocyanates and find that the inhibition is incomplete, probably because of decomposition of the reagent. The inhibition type is 'mixed', because hexose-transporter ligands such as maltose and cytochalasin B only give partial protection from inhibition. This suggests that a liganded-transporter-hexose isothiocyanate ternary complex is formed. We have compared the labelling of red-blood-cell membranes by [14C]MITC (D-maltose isothiocyanate) with the labelling obtained using a photoaffinity probe (ASA-BMPA [2-N-(4-azidosalicyloyl)-1,3-bis-(D-mannos-4'-yloxy)-2 -propylamine]) which gives specific labelling of the hexose transporter in band 4.5. [14C]MITC gives a partially D-glucose-displaceable labelling of a band 3 component in the same cell preparations which show ASA-BMPA labelling of band 4.5. This eliminates the possibility that band 4.5 labelling can only occur when the HITC (hexose isothiocyanate) binding protein in band 3 is proteolysed. HITC pretreatment does not decrease ASA-BMPA labelling of the exofacial site of band 4.5. This is also consistent with the formation of ternary complex. However, HITC pretreatment inhibits both reversible and photoactivated covalent [3H]cytochalasin B binding to band 4.5. These results suggest that, in the intact cell, interactions between a band 3 HITC-binding component and the inside cytochalasin B-binding site on the hexose transporter in band 4.5 may occur.

Immigrants and the hospice

This is the first published report on immigrants and hospices. From 1979 to 1985 St Mary's cared for 74 European, Afro-caribbean and Asian immigrants. Immigrants referred to the Hospice were more likely to be accepted for care than indigenous patients. Women from the Indian sub-continent (mean age 42 years) were the youngest immigrants needing hospice care. European immigrants were older and more likely to receive hospice care than other immigrants.