Randomized clinical trial to determine the effect of nasogastric drainage on tracheal acid aspiration following oesophagectomy (Br J Surg 2006; 93: 547 -552).
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Acids↗
Biomedical subjects
E Cheong
Publications and source records attributed to E Cheong.
Prospective randomized trial of laparoscopic gastrojejunostomy versus duodenal stenting for malignant gastric outflow obstruction.
BACKGROUND: We prospectively compared laparoscopic gastrojejunostomy with duodenal stenting as a means of palliating malignant gastric outflow obstruction. METHODS: A total of 27 patients with malignant gastric outflow obstruction were randomized to either laparoscopic gastrojejunostomy (LGJ) or duodenal stenting (DS) over a 3-year period. RESULTS: Thirteen patients underwent successful LGJ and 10 had successful DS. Eight patients had complications after LGJ, but none had complications after DS. Patients who underwent LGJ had a significant increase in visual analog pain score at day 1 (p = 0.05), and also had a longer hospital stay compared to those who underwent DS (11.4 vs. 5.2 days, p = 0.02). After DS, patients experienced an improvement in physical health at 1 month as measured using the Short Form-36 (SF-36) questionnaire (p < 0.01). There was no change following LGJ. CONCLUSION: Duodenal stenting is a safe means of palliating malignant gastric outflow obstruction. It offers significant advantages for patients compared with minimal-access surgery.
Aged↗
Synthetic and naturally occurring COX-2 inhibitors suppress proliferation in a human oesophageal adenocarcinoma cell line (OE33) by inducing apoptosis and cell cycle arrest.
Epidemiological studies suggest that the use of NSAIDs and/or a high intake of fruit and vegetables reduce the risk of oesophageal adenocarcinoma. Since COX-2 is up-regulated in Barrett's oesophageal carcinogenesis, the protective effect of NSAIDs and natural food components might reflect COX-2 inhibition. We explored the effects of quercetin, a natural flavonoid with a potent COX-2 inhibitory activity, and two commercially available selective COX-2 inhibitors (NS-398 and nimesulide) on cell proliferation, apoptosis, PGE2 production and COX-2 mRNA expression in a human oesophageal adenocarcinoma cell line (OE33). Changes in the relative numbers of adherent and floating cells were quantified and apoptotic cells were identified using ethidium bromide and acridine orange staining under fluorescence microscopy. Flow cytometric analysis of adherent and floating cells was used to quantify apoptosis and to examine the effects of the agents on the cell cycle. After 48 h exposure at concentrations of > or =1 microM both COX-2 inhibitors and quercetin suppressed cell proliferation (P < 0.01) and increased the fraction of floating apoptotic cells. At higher concentrations (50 microM) and longer exposure (48 h) the effects of quercetin were significantly greater than those of the selective COX-2 inhibitors (P < 0.01). Cell cycle analyses showed that quercetin blocked cells in S phase, while the selective COX-2 inhibitors blocked cells in G1/S interphase. COX-2 mRNA expression was suppressed by quercetin and the synthetic COX-2 inhibitors in a time- and dose-dependent manner. Quercetin and the synthetic COX-2 inhibitors (10 microM) suppressed PGE2 production by approximately 70% after 24 h exposure (P < 0.001). We conclude that OE33 is a useful model for the study of COX-2 expression and associated phenomena in human adenocarcinoma cells. Synthetic COX-2 inhibitors and the food-borne flavonoid quercetin suppress proliferation, induce apoptosis and cell cycle block in human oesophageal adenocarcinoma cells in vitro, and future studies should assess their effects in vivo.
Adenocarcinoma↗
Attendance at a pain clinic with severe chronic pain after open and laparoscopic inguinal hernia repairs.
BACKGROUND: The aim was to compare the frequency of severe chronic pain that required attendance at a pain clinic after open and laparoscopic inguinal hernia repairs. METHODS: This was a retrospective analysis of 7999 patients who underwent inguinal hernia repair between January 1994 and December 2001. The definition of severe chronic pain was pain related to inguinal hernia surgery that was bad enough for the patient to seek further medical help and be referred to the specialist pain clinic after exclusion of surgically correctable pathology such as hernia recurrence. RESULTS: During the study there were 7153 open repairs and 846 laparoscopic repairs. Sixty-nine patients (1.0 per cent) were referred to the pain clinic a median of 16.9 (range 5.1-69.4) months after open hernia repair. Three patients (0.4 per cent) were referred a median of 16.5 (range 7.3-21.5) months after laparoscopic hernia repair (P = 0.045). CONCLUSION: Laparoscopic inguinal hernia repair was associated with a significantly lower frequency of attendance at the pain clinic with severe chronic pain.
Chronic Disease↗
Cyclo-oxygenase-2 expression in Barrett's oesophageal carcinogenesis: an immunohistochemical study.
BACKGROUND: The incidence of Barrett's oesophageal adenocarcinoma is increasing more rapidly than any other malignancy in industrialized countries. Cyclo-oxygenase-2 appears to play an important role in gastrointestinal carcinogenesis. Previous studies on cyclo-oxygenase-2 expression in Barrett's oesophageal carcinogenesis have utilized tissue samples obtained from different patients. We sought a definitive comparison of cyclo-oxygenase-2 expression in the sequence of Barrett's metaplasia-dysplasia-adenocarcinoma within the same patients. METHODS: Paraffin-embedded oesophago-gastrectomy specimens from 20 patients, containing successive stages of Barrett's metaplasia, high-grade dysplasia and adenocarcinoma, were analysed for cyclo-oxygenase-2 expression by immunohistochemistry. RESULTS: Cyclo-oxygenase-2 was constitutively expressed in the basal layers of cells in the adjacent normal squamous oesophageal epithelium, but a higher cyclo-oxygenase-2 expression was observed in Barrett's metaplasia. A further increase in cyclo-oxygenase-2 expression was detected in high-grade dysplasia, but cyclo-oxygenase-2 was decreased in adenocarcinoma tissue, regardless of its stage or level of differentiation. CONCLUSIONS: Cyclo-oxygenase-2 expression is progressively increased when squamous oesophageal epithelium develops into Barrett's metaplastic epithelium and then into high-grade dysplasia, but appears to decrease when adenocarcinoma develops. These findings may be significant for an effective chemo-prevention strategy with selective cyclo-oxygenase-2 inhibitors.
Adenocarcinoma↗
Low N-ethylmaleimide concentrations activate ryanodine receptors by a reversible interaction, not an alkylation of critical thiols.
Previous studies proposed that N-ethylmaleimide (NEM) alkylates 3 classes of thiols on skeletal muscle ryanodine receptors (RyRs) producing 3 phases of channel modification, as function of time and concentration. NEM (5 mm) decreased, increased, and then decreased the open probability (P(o)) of the channel by thiol alkylation, a reaction not reversed by reducing agents. We now show that low NEM concentrations (20-200 microm) elicit Ca(2+) release from sarcoplasmic reticulum (SR) vesicles, but contrary to expectations, the effect was fully reversed by reducing agents or by washing SR vesicles. In bilayers, NEM (0.2 mm) increased P(o) of RyRs within seconds when added to the cis (not trans) side, and dithiothreitol (DTT; 1 mm) decreased P(o) in seconds. High (5 mm) NEM concentrations elicited SR Ca(2+) release that was not reversed by DTT, as expected for an alkylation reaction. A non-sulfhydryl reagent structurally related to NEM, N-ethylsuccinimide (0.1-0.5 mm), also elicited SR Ca(2+) release that was not reversed by DTT (1 mm). Other alkylating agents elicited SR Ca(2+) release, which was fully (N-methylmaleimide) or partially (iodoacetic acid) reversed by DTT and inhibited by ruthenium red. Nitric oxide (NO) donors at concentrations that did not activate RyRs inhibited NEM-induced Ca(2+) release, most likely by an interaction of NO with NEM rather than an inactivation of RyRs by NO. Thus, at low concentrations, NEM does not act as a selective thiol reagent and activates RyRs without alkylating critical thiols indicating that the multiple phases of ryanodine binding are unrelated to RyR activity or to NEM alkylation of RyRs.
Alkylation↗
Gas chromatographic amino acid profiling of wine samples for pattern recognition.
A rapid gas chromatographic profiling and screening method is described for the determination of free amino acids in wine samples. The amino acids in alkaline aqueous wines were allowed to react with isobutyl chloroformate. The resulting N(O,S)-isobutyloxycarbonyl amino acids were extracted by solid-phase extraction using Chromosorb P as the adsorbent and diethyl ether as the eluent after acidification, and then converted into stable tert.-butyldimethylsilyl derivatives with subsequent analysis by dual-capillary column gas chromatography and gas chromatography-mass spectrometry. Seventeen free amino acids were identified from the four wine brands studied. When the GC profiles were simplified to the corresponding amino acid retention index spectra in bar graphical form, they presented characteristic patterns for each wine brand. Stepwise discriminant analysis performed on the amino acid profiles provided star symbols characteristic of the wine brands.
Amino Acids↗
Glial-Schwann cell specialisations at the central-peripheral nervous system transition of a cyclostome: an ultrastructural study.
This study describes for the first time the central (CNS)-peripheral (PNS) nervous system transitional zone (TZ) of a member of the vertebrate class Agnatha, namely, the sea lamprey. It is concerned in particular with the glial tissue contribution to the TZ and the Schwann cell-CNS interface. Plastic-embedded specimens of spinal cord and nerve roots were examined using light and electron microscopy. At the TZ of each root a glial barrier, continuous with and similar in form to the surrounding glia limitans, stretches across the nerve bundle. In possessing such a barrier the lamprey TZ follows the general vertebrate pattern and differs from the Cephalochordata and invertebrates where a corresponding barrier is absent. The glial barrier is of similar thickness to the glia limitans generally, unlike in the mammal where it is thicker at the TZ than elsewhere. All lamprey axons are unmyelinated peripherally and most of them traverse the glial TZ barrier singly in individual tunnels. In this they resemble mammalian axons of similar calibre (which are, however, myelinated), but differ from unmyelinated mammalian axons, which generally traverse it in bundles. The lamprey TZ has specialisations not found in mammals. These include prominent, multiple interconnected strata of microfilament bundles which are continuous deeply with glial filament bundles and which lie under the surface plasmalemma of the glia limitans, to which they are connected by hemidesmosomes. Features of the mature lamprey TZ resemble those of developing mammalian TZs. For example, slender Schwann cell processes extend below the cord surface and become closely apposed to glial processes. In addition, together with the axon, the TZ glial processes and the basal lamina, they bound an extensive periaxonal network of spaces at the TZ, into which fine Schwann cell processes project. Accordingly, the networks could represent a primitive form of node gap.
Animals↗
The role of ATP and free ADP in metabolic coupling during fuel-stimulated insulin release from islet beta-cells in the isolated perfused rat pancreas.
The isolated perfused rat pancreas was used to test the hypothesis that total cellular ATP or the ratio of ATP/free ADP plays the primary role in coupling intermediary metabolism to the biophysical events that are the basis of glucose-stimulated insulin release. The pancreas was preperfused for 20 min with 4.0 mM of a physiological mixture of 20 amino acids plus 4.2 mM glucose, and insulin release was then stimulated for 150 s by suddenly increasing the glucose to 8.3 mM. The pancreas was sampled at 24, 48, 72, and 150 s after the switch. The content of total ATP, ADP, AMP, Pi, phosphocreatine, and creatine were measured in beta-cell enriched cores of pancreatic islets microdissected from freeze-dried pancreas cryostat sections. Metabolites were measured by quantitative histochemical enzymatic cycling techniques. Modeling studies were carried out to assess the impact of biochemical analytical results on the membrane potential of the beta-cells. The level of free ADP was calculated using the creatine kinase equilibrium reaction and an intracellular pH of 7.2. First phase insulin release was stimulated at least 10-fold with the maximum reached 45 s after adding high glucose. The biochemical analytical data demonstrate that the total cellular level of the putative coupling factor ATP and of the ratios ATP/free ADP and ATP/free ADP x Pi are not significantly influenced by a glucose level change that causes a more than 10-fold surge of insulin release. The strength and limitations of the present experimental strategy and the implications of the results for our understanding of metabolic coupling in glucose-stimulated insulin release are discussed.
Adenosine Diphosphate↗
Hormone secretion by isolated perfused pancreas of aging Fischer 344 rats.
This is the first study investigating hormone secretion by the isolated perfused pancreas of the aged Fischer 344 rat. Nutrient-induced release of insulin, glucagon, and somatostatin in overnight-fasted rats aged 2, 10, 18, 24, and 30 mo was studied. After an equilibration period, the pancreas was perfused for 20 min with buffer A (containing 4.2 mM glucose plus a 3.5 mM mixture of amino acids) then for 20 min with buffer B (containing 8.3 mM glucose and 7.0 mM amino acids). When stimulated by buffer B, the amount of insulin secreted increased (P less than 0.05) from immaturity (2 mo) to adulthood (10-18 mo) because of growth of the organ. From adulthood to very old age an equal amount of insulin was released in all groups during the last 19 min of perfusion with buffer B. Fasting blood glucose levels remained constant throughout life, whereas pancreatic insulin stores and plasma insulin levels rose, reaching peak values at 18 mo. The alpha-cell appeared to be deemphasized relative to the beta-cell during development but not thereafter, as indicated by the findings that from immaturity to adulthood pancreatic glucagon stores expanded less than insulin stores and that glucagon release significantly decreased. Only minor changes in somatostatin release from the delta-cells were observed after the rat reached adulthood. We conclude that the endocrine secretory response of the pancreas is well maintained throughout life in the Fischer 344 rat.
Aging↗
Effect of linogliride on hormone release from perfused rat pancreas. Fuel dependence and desensitization by tolbutamide.
We examined the effect of the hypoglycemic drug linogliride on hormone release from the in vitro perfused rat pancreas. Linogliride stimulated insulin release in the absence of glucose either in the presence or absence of a physiological mixture of amino acids. In addition, linogliride inhibited amino acid-induced glucagon release. Half-maximal effects of linogliride on insulin and glucagon release were achieved at concentrations as low as 26 and 3 microM, respectively. The effects of linogliride on hormone release largely resembled those of tolbutamide. In the absence of amino acids, the stimulation of insulin release by linogliride or tolbutamide was transient. When the pancreas had been preperfused for 20 min with tolbutamide, linogliride no longer had an effect on hormone release. Likewise, tolbutamide remained without effect in pancreases preperfused with linogliride. These data suggest that linogliride and tolbutamide may have a similar mechanism of action.
Amino Acids↗
Phormia regina myiasis in a malignant wound.
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Carcinoma, Squamous Cell↗
Functional polymeric microspheres based on 2-hydroxyethyl methacrylate for immunochemical studies.
Co gamma irradiation of 2-hydroxethyl methacrylate in the presence or in the absence of other acrylic monomers was found to constitute an effective technique for the synthesis of hydrophilic functional microspheres in the size range of approxumately 0.3 to 3 mu in diameter. The effect of monomer concentration, steric stabilization, and electrostatic interaction on the particle size was investigated. Experimental conditions were determined to obtain desired particle sizes of relatively narrow distribution. It was shown that particles may be formed without intermediate micelles, i.e., by homogeneous nucleation, and the rate of particle formation is affected primarily by the rate of particle coalescence in the initial stages of the reaction. When covalently bound to antibodies these microspheres were successfully used to label murine and human lymphocytes.
Acrylates↗