Changes in the gastric enteric nervous system and muscle: A case report on two patients with diabetic gastroparesis

<p>Abstract</p> <p>Background</p> <p>The pathophysiological basis of diabetic gastroparesis is poorly understood, in large part due to the almost complete lack of data on neuropathological and molecular changes in the stomachs of patients. Experimental models indicate various lesions affecting the vagus, muscle, enteric neurons, interstitial cells of Cajal (ICC) or other cellular components. The aim of this study was to use modern analytical methods to determine morphological and molecular changes in the gastric wall in patients with diabetic gastroparesis.</p> <p>Methods</p> <p>Full thickness gastric biopsies were obtained laparoscopically from two gastroparetic patients undergoing surgical intervention and from disease-free areas of control subjects undergoing other forms of gastric surgery. Samples were processed for histological and immunohistochemical examination.</p> <p>Results</p> <p>Although both patients had severe refractory symptoms with malnutrition, requiring the placement of a gastric stimulator, one of them had no significant abnormalities as compared with controls. This patient had an abrupt onset of symptoms with a relatively short duration of diabetes that was well controlled. By contrast, the other patient had long standing brittle and poorly controlled diabetes with numerous episodes of diabetic ketoacidosis and frequent hypoglycemic episodes. Histological examination in this patient revealed increased fibrosis in the muscle layers as well as significantly fewer nerve fibers and myenteric neurons as assessed by PGP9.5 staining. Further, significant reduction was seen in staining for neuronal nitric oxide synthase, heme oxygenase-2, tyrosine hydroxylase as well as for c-KIT.</p> <p>Conclusion</p> <p>We conclude that poor metabolic control is associated with significant pathological changes in the gastric wall that affect all major components including muscle, neurons and ICC. Severe symptoms can occur in the absence of these changes, however and may reflect vagal, central or hormonal influences. Gastroparesis is therefore likely to be a heterogeneous disorder. Careful molecular and pathological analysis may allow more precise phenotypic differentiation and shed insight into the underlying mechanisms as well as identify novel therapeutic targets.</p

A review of methods for assessment of the rate of gastric emptying in the dog and cat: 1898-2002

Gastric emptying is the process by which food is delivered to the small intestine at a rate and in a form that optimizes intestinal absorption of nutrients. The rate of gastric emptying is subject to alteration by physiological, pharmacological, and pathological conditions. Gastric emptying of solids is of greater clinical significance because disordered gastric emptying rarely is detectable in the liquid phase. Imaging techniques have the disadvantage of requiring restraint of the animal and access to expensive equipment. Radiographic methods require administration of test meals that are not similar to food. Scintigraphy is the gold standard method for assessment of gastric emptying but requires administration of a radioisotope. Magnetic resonance imaging has not yet been applied for assessment of gastric emptying in small animals. Ultrasonography is a potentially useful, but subjective, method for assessment of gastric emptying in dogs. Gastric tracer methods require insertion of gastric or intestinal cannulae and are rarely applied outside of the research laboratory. The paracetamol absorption test has been applied for assessment of liquid phase gastric emptying in the dog, but requires IV cannulation. The gastric emptying breath test is a noninvasive method for assessment of gastric emptying that has been applied in dogs and cats. This method can be carried out away from the veterinary hospital, but the effects of physiological and pathological abnormalities on the test are not known. Advances in technology will facilitate the development of reliable methods for assessment of gastric emptying in small animals

Evolutional dynamics of product innovation: the case of consumer electronics

This report addresses the question of how product innovation occurs. In other words, where does it originate and what induces it? The aim of the authors has been to expand upon and systematize the research presented in our previous study (Orihata, M., Watanabe, C., Technovation, in press) through the application of a new, evolutionary approach. We have chosen to focus on the consumer electronics industry, taking as our case studies three producers of revolutionary products such as Sony's video camera, Sharp's PDA (Personal Digital Assistance) and Toshiba's notebook personal computer. These examples have the virtue of encompassing both visual and text-based data transmission devices, as well as hand-script input and keyboard input methods. The main point we shall consider here is the stage that takes place before product innovation occurs, the process that we have termed “institutional inducement”, which forms part of the feedback loop between the market, or environment, and the producer. Because this process is “a flow of information and knowledge” we have structured it using a semiotic methodology, which has led us to conclude that product innovation is induced by the creation of new product concepts. In accordance with this, we propose that the evolutionary, dynamic pattern of product innovation is linked to the institutional trajectory

The interaction between product concept and institutional inducement: A new driver of product innovation

The findings of our study clearly suggest that “product concept” drives product innovation. The very term “product concept” itself is often used in a vague, almost philosophical way: though it appears frequently in economic literature, the authors of this report feel that its true significance is not widely recognized. However, based on the enterprises we examined in the course of this study, not only is the notion of “product concept” frequently invoked by managers as an operational objective, but it does actually play an important role in product development. Technological innovation can take place at various stages of the process of product innovation, but this does not mean that it is absolutely the “driving” force behind product innovation. Rather, our study found that technological innovation occurred in order to give a product concept actual “material substance”. Moreover, we observed that technological innovation plays a vital role as a strategy in creating competitive barriers between companies and their competitors. But following Kuhn, who first demonstrated that innovation is the creation of new paradigms, we found that product innovation occurred in the wake of new concepts. In other words, technological innovation is pulled along by the advance of product concepts