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  • 1
    ISSN: 1432-1424
    Keywords: Ca2+ oscillations ; Ca2+ wave ; sarcoplasmic reticulum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Intracellular calcium [Ca2+] i measurements in cell suspension of gastrointestinal myocytes have suggested a single [Ca2+] i transient followed by a steady-state increase as the characteristic [Ca2+] i response of these cells. In the present study, we used digital video imaging techniques in freshly dispersed myocytes from the rabbit colon, to characterize the spatiotemporal pattern of the [Ca2+] i signal in single cells. The distribution of [Ca2+] i in resting and stimulated cells was nonhomogeneous, with gradients of high [Ca2+] i present in the subplasmalemmal space and in one cell pole. [Ca2+] i gradients within these regions were not constant but showed temporal changes in the form of [Ca2+] i oscillations and spatial changes in the form of [Ca2+] i waves. [Ca2+] i oscillations in unstimulated cells (n = 60) were independent of extracellular [Ca2+] and had a mean frequency of 12.6 +1.1 oscillations per min. The baseline [Ca2+], was 171 ± 13 nm and the mean oscillation amplitude was 194 ± 12 nm. Generation of [Ca2+] i waves was also independent of influx of extracellular Ca2+. [Ca2+] i waves originated in one cell pole and were visualized as propagation mostly along the subplasmalemmal space or occasionally throughout the cytoplasm. The mean velocity was 23 +3 μm per sec (n = 6). Increases of [Ca2+] i induced by different agonists were encoded into changes of baseline [Ca2+] i and the amplitude of oscillations, but not into their frequency. The observed spatiotemporal pattern of [Ca2+] i regulation may be the underlying mechanism for slow wave generation and propagation in this tissue. These findings are consistent with a [Ca2+] i regulation whereby cell regulators modulate the spatiotemporal pattern of intracellularly generated [Ca2+] i oscillations.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Inhibitory amino acids have antinociceptive actions in the spinal cord that may involve inhibition of neurotransmitter release from primary afferents. Rat spinal cord slices with dorsal roots were used to study the effect of GABA and glycine on substance P release, assessed by the internalization of neurokinin 1 receptors. After electrical stimulation of the dorsal root at 100 Hz, about half of neurokinin 1 receptor-immunoreactive neurons in laminae I–IIo showed internalization. This internalization was inhibited by GABA (100 μm) and the GABAB agonist R-baclofen (10 μm), but not by the GABAA agonist muscimol (20 μm) or glycine (100 μm). The GABAB antagonist 2-hydroxysaclofen (100 μm) reversed the inhibitory effect of GABA, but not the GABAA antagonist bicuculline (100 μm). These findings demonstrate that GABAB receptors, but not GABAA or glycine receptors, inhibit substance P release induced by dorsal root stimulation. In contrast, R-baclofen did not inhibit the internalization produced by NMDA (100 μm), indicating that the stimulatory effect of NMDA receptors on substance P release is able to surmount the inhibitory effect of GABAB receptors. In the presence of the GABAB antagonist 2-hydroxysaclofen (100 μm), but not in its absence, stimulation of the dorsal root at 1 or 10 Hz was able to elicit internalization, which was not inhibited by the NMDA receptor antagonist AP-5 (50 μm) or the channel blocker MK-801 (10 μm). Therefore, inhibition of substance P release by GABAB receptors is tonic, and in its absence SP release no longer requires NMDA receptor activation.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2323
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé La conservation du pylore dans la duodénopancréatectomie céphalique n'augmente pas la morbidité ou la mortalité opératoire, et ne diminue pas la survie à distance. Cependant les bénéfices à long terme de cette conservation restent inconnus. Dans cette étude, on a comparé l'état fonctionnel de 6 patients ayant survécu après l'opération de Whipple (survie moyenne, 4.7 ans; extrêmes, 1 et 7 ans) à celui de 6 autres patients ayant subi une duodénopancréatectomie céphalique avec conservation du pylore (moyenne, 3.0 ans; extrêmes, 1 et 7 ans). Tous les patients ont répondu à un questionnaire concernant les suites de leur gastrectomie. Après prélèvement sanguin à jeun, 10 des 12 patients ont subi une fibroscopie: des biopsies systématiques périanastomotiques et gastriques moyennes ont été pratiquées pour évaluer le degré d'inflammation. La vidange gastrique (phase solide et liquide) a été évaluée aux isotopes. Ces résultats ont été comparés entre eux et à ceux de 7 patients normaux étudiés selon le même méthodologie. L'analyse des réponses aux questionnaires, et des résultats biologiques n'a pas permis de mettre en évidence une différence significative entre les 2 groupes opérés. Les taux de carotène sérique étaient bas chez la plupart des patients. La majorité des patients présentaient des anomalies des taux de fer. Il n'y avait pas de différence significative à l'examen endoscopique et les résultats des biopsies ne différaient pas dans les 2 groupes. La vidange gastrique des liquides était significativement plus longue chez les patients après duodénopancréatectomie standard (t1/2=98.3±26.2 min) que chez les patients avec conservation du pylore (t1/2=37.5±10.9 min) ou chez les sujets normaux (t1/2=33.1±2.8 min). Nous concluons que les résultats fonctionnels à long terme de la conservation pylorique sont aussi bons que ceux de la duodénopancréatectomie céphalique classique. Ainsi, nous croyons que la conservation du pylore, évitant la vagotomie et la résection gastrique, mérite d'être envisagée lors de toute duodénopancréatectomie.
    Abstract: Resumen La preservación del píloro en la pancreatoduodenectomía, procedimiento introducido por el autor senior en 1978 con el propósito de eliminar los síntomas postgastrectomía, puede ser realizada sin aumento de la morbilidad o mortalidad y sin decremento de la sobrevida; sin embargo, sus beneficios a largo plazo todavía no han sido comprobados. En el presente estudio se valoró el estado funcional de pacientes recuperados después de una pancreaticoduodenectomía con preservación del píloro, comparando 6 sobrevivientes a largo plazo sometidos a la operación de Whipple del tipo estandar (1–7 años postoperatorios; promedio, 4.7 años) con un grupo similar de 6 pacientes sometidos a la pancreaticoduodenectomía con preservación del píloro (1–7 anos postoperatorios; promedio, 3.0 años). Todos los pacientes respondieron un cuestionario para valorar síntomas postgastrectomía. Se obtuvieron muestras de sangre en ayunas para análisis hematológico y bioquímico. Diez de los 12 pacientes fueron luego sometidos a endoscopia; se tomaron biopsias perianastomóticas y de la región gástrica media, las cuales fueron clasificadas según el grado de inflamación. El vaciamiento gástrico tanto de la fase líquida como de la sólida fue medido utilizando comida marcada con isótopos, y los datos fueron comparados entre los grupos del estudio y también con 7 personas controles normales previamente estudiadas utilizando la misma metodología. El análisis de los resultados del cuestionario, así como de los valores de los exámenes de laboratorio, no demostraron diferencias significativas entre los 2 grupos de pacientes operados. Los niveles séricos de carotenos aparecieron bajos en la mayoría de los pacientes y algunos demonstraron índices anormales de homeostasis férrica. No se observaron diferencias significativas en los exámenes endoscópicos, y tampoco en los resultados de las biopsias entre los 2 grupos quirúrgicos. El vaciamento gástrico de líquidos apareció prolongado en forma significativa en los pacientes con pancreatoduodenectomía del tipo estandar (t1/2=98.3±26.2 min) en comparación con aquellos con la operación con preservación del píloro (t1/2= 37.5±10.9 min) o con los controles normales (t1/2=33.1±2.8 min). Nuestra conclusión es que a largo plazo la preservación del píloro parece ser por lo menos funcionalmente equivalente a la pancreatoduodenectomía estándar. Como tal, consideramos que la preservación del píloro, que hace innecesaria la vagotomía y la resección gástrica, merece ser seriamente considerada en el curso de una pancreatoduodenectomía.
    Notes: Abstract Although pyloric preservation can be performed during pancreaticoduodenectomy without increased morbidity or mortality or decreased survival, the long-term benefit of this technique remains unproven. In this study, the functional status of patients recovered from pyloric-preserving pancreaticoduodenectomy was evaluated by comparing 6 long-term survivors of the standard Whipple procedure (1–7 years postoperative; mean, 4.7 yr) to a similar group of 6 patients recovered from pylorus preservation pancreaticoduodenectomy (1–7 years postoperative; mean, 3.0 yr). All patients completed a questionnaire evaluating postgastrectomy symptoms. Fasting blood specimens were obtained for hematologic and biochemical analysis. Ten of the 12 patients then underwent endoscopy; perianastomotic and midgastric biopsies were graded for inflammation. Gastric emptying of both liquid and solid phases was measured with an isotopically-labeled meal. Gastric emptying data were compared between groups and also to a group of 7 normal controls studied previously using the same methodology. Analysis of questionnaire results and mean laboratory values revealed no significant differences between the 2 surgical groups. Serum carotene levels were low in most patients. Several patients demonstrated abnormal indices of iron homeostasis. No significant abnormalities were noted on endoscopic examinations and biopsy results did not differ between the 2 surgical groups. Liquid gastric emptying was significantly prolonged in patients following standard pancreaticoduodenectomy (t1/2=98.3±26.2 min) as compared to pylorus preservation patients (t1/2=37.5±10.9 min) or normal controls (t1/2=33.1±2.8 min). We conclude that, in the long-term, pylorus preservation appears to be at least functionally equivalent to the standard pancreaticoduodenectomy. As such, we believe that pyloric preservation, obviating vagotomy and gastric resection, deserves consideration during pancreaticoduodenectomy.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-2568
    Keywords: anorexia nervosa ; antroduodenal motility ; dysmotility ; pseudobstruction ; malnutrition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Anorexia nervosa is considered one type of eating disorder that may result in severe malnutrition. Patients with this disorder commonly complain of postprandial nausea, abdominal pain, and distension. We describe the radiologic and motility abnormalities associated with anorexia nervosa in a 21-year-old female. Barium gastrointestinal series demonstrated marked dilation of the duodenum, with prolongation of intestinal transit. A 4-hr fasting gastroduodenal motility study showed no propagating migrating motor complexes (MMC). Prolonged, but nonpropagating, bursts of high-amplitude phasic and tonic contractions were seen in the duodenum. In contrast, antral contractions were of low amplitude and esophageal motor function was normal. Metoclopramide and edrophonium caused an increase in gastroduodenal motor activity, but increased contractions were not associated with symptoms. Following a renutrition program that raised the patient's weight from 64 to 80% of her ideal body weight, the radiographic abnormalities and gastrointestinal dysmotility resolved completely. These observations suggest that anorexia-associated gastrointestinal motor dysfunctions are a consequence, not the cause of the generalized protein-calorie malnutrition associated with anorexia nervosa. The facts that motility in different parts of the gut is affected to different degrees and that gastric and duodenal muscle responds normally to exogenous stimulation argue against a generalized myogenic dysfunction and, rather, point to a reversible dysfunction of neural regulation.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Digestive diseases and sciences 33 (1988), S. 71S 
    ISSN: 1573-2568
    Keywords: substance P ; primary afferent nerves ; capsaicin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Neurogenic inflammation is a reaction which includes vasodilation, plasma extravasation, and smooth muscle contraction elicited by activation of and release of mediators from unmyelinated afferent nerve endings. Further release of inflammatory mediators follows activation of axon collaterals associated with these afferent nerve endings as axon reflexes. Substance P, somatostatin, vasoactive intestinal polypeptide, and calcitonin generelated peptide are candidate mediators. Recent evidence suggests that several of these peptides may be colocalized either with one or more other peptides or with acetylcholine or noradrenalin. Communicating pathways exist between nerves within the mucosa and the muscle layers. Both long and short visceral reflexes occur. Inflammatory, mechanical, or chemical stimuli reaching the mucosa may release peptides from peripheral nerve endings. Thus neurogenic inflammation may be an important factor in inflammatory bowel disease.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-2568
    Keywords: gastric emptying ; intestinal pseudoobstruction ; gastrin ; pancreatic polypeptide ; motility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Gastric emptying of solids and liquids was evaluated simultaneously in 11 patients with intestinal pseudoobstruction. Despite a normal upper gastrointestinal series in most patients, over two thirds of the patients had abnormal gastric emptying of solids and/or liquids. Half these patients exhibited delayed emptying of solids and accelerated emptying of liquids. Alterations in motility patterns were observed in the four patients tested including decreased frequency or absence of migrating motor complexes originating in the stomach, shortening or absence of phase I, and loss of distinct fasted and fed patterns. Both basal values and mean postprandial increments in serum gastrin concentrations were lower in the patients, whereas no significant difference was found for pancreatic polypeptide concentrations when compared to normals. Our findings emphasize the functional heterogeneity of patients with intestinal pseudoobstruction. In addition, in contrast to previous reports which used barium meals to access gastric function, we observed a high prevalence of gastric emptying disturbances in these patients, suggesting that the motility disturbance is not restricted to the small intestine.
    Type of Medium: Electronic Resource
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