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[Ultrastructure of diabetic autonomic neuropathy of the gastrointestinal tract].

Gastrointestinal motility disorders induced by diabetes mellitus are most commonly manifested in the colon, and are considered to be an expression of diabetic autonomic polyneuropathy. In this study, for the first time, the intrinsic nervous system of the bowel has been subjected to an ultrastructural and morphometric examination in rectal biopsy material obtained from diabetics with and without diabetic enteropathy. In patients with diabetic enteropathy, the nerves of the submucous plexus (Meissner's plexus) revealed significant swelling of the axons, as an expression of neural degeneration. Furthermore, in about a half of these patients, thickening of the basal membrane of Schwann's cells was also detected. Additional, although unspecific, changes found in the diabetics were a quantitative increase in the lysosomes, lipofuscin and glycogen in the Schwann cells. The ultrastructural findings represent evidence for the presence of an intrinsic autonomic polyneuropathy in diabetics with diabetic enteropathy. At the same time, they indicate that the diagnosis of diabetic enteropathy is no longer merely an "exclusion" diagnosis.

Adult↗

Biopsy of the gastrointestinal tract.

Gastrointestinal biopsy is a potentially powerful tool, but it is easy to do it incorrectly. If clinicians are careless in performing or submitting biopsies, or if they blindly believe whatever the histopathology report says, they are abdicating their responsibility to the client and patient. Two comments seem most appropriate. First, the goal of endoscopy is not to be able to place the tip of an endoscope in a particular location; rather, the goal of endoscopy is to be able to access a particular location and then take a diagnostic specimen well enough that surgery can be avoided. Second, attention to detail is worth at least as much if not more than technology.

Animals↗

[Neuroendocrine tumours of the gastrointestinal tract].

Gastrointestinal neuroendocrine tumours are classified as functioning or non-functioning according to the presence or absence of a clinically evident hypersecretion syndrome. In foregut tumours the presence of autonomous hormone secretion and the respective hypersecretion syndrome indicate functionality. Abdominal ultrasound (US), computed tomography (CT), magnetic resonance tomography (MRT) and somatostatin receptor scintigraphy (SRS) are used for localisation of the primary tumour and metastasis. Invasive procedures such as endoscopic US, intraoperative US or intraoperative duodenal transillumination are useful to localise small (< 1 cm) tumours. For localised tumours surgery is the first line treatment. In metastatic disease symptomatic therapy, biotherapy and chemotherapy are available. Cytoreductive therapy such as embolisation, chemoembolisation, thermo- or cryotherapy, or radio-receptor therapy are additional options. The first symptom of most neuroendocrine midgut tumours is abdominal pain. An increased chromogranin-A plasma concentration or 5-hydroxyindoleacetic acid 24-h urinary excretion indicates the neuroendocrine origin of the tumour or the possibility of a carcinoid syndrome, respectively. Surgical therapy prolongs survival but is rarely curative. Biotherapy is effective as symptomatic therapy. However, its cytoreductive potency is low. Chemotherapy is less effective in midgut tumours compared to foregut tumours. Cytoreductive strategies (chemoembolisation, thermo- or cryotherapy, cytoreductive surgery) and radio-receptor therapy may offer new therapeutic options. However, their definitive value has yet to be defined.

Antineoplastic Agents↗

AIDS and the gastrointestinal tract.

Gastrointestinal disease in AIDS most often affects three major areas: the bowel, the esophagus, and the liver. Investigation should be tailored to identify treatable causes of disease, bearing in mind that multiple infections, superinfection, and untreatable diseases are common. Clinical decisions must be made regarding both the level of investigation necessary and the best testing procedures to use. Treatment is often only symptomatic, but in some cases a specific pathogen can be targeted.

Acquired Immunodeficiency Syndrome↗

Down's syndrome and the gastrointestinal tract.

Gastrointestinal (GI) abnormalities are frequent in patients with Down's syndrome. In a 12-year retrospective review, we identified 187 patients with Down's syndrome admitted to the Columbia-Presbyterian Medical Center. Twenty-seven had major GI disorders, the most common being duodenal stenosis (DS, nine), gastroesophageal reflux (GER, five), imperforate anus (five), and Hirschsprung's disease (four). The mortality for the whole group was 11% (20 patients). The mortality in the small group of patients with duodenal stenosis was particularly high (five out of nine, or 56%). Associated congenital heart disease, especially endocardial cushion defects, and the frequent occurrence of pneumonia contributed to this high mortality rate.

Adolescent↗

Carbonic anhydrases in normal gastrointestinal tract and gastrointestinal tumours.

Carbonic anhydrases (CAs) catalyse the hydration of CO2 to bicarbonate at physiological pH. This chemical interconversion is crucial since HCO3- is the substrate for several biosynthetic reactions. This review is focused on the distribution and role of CA isoenzymes in both normal and pathological gastrointestinal (GI) tract tissues. It has been known for many years that CAs are widely present in the GI tract and play important roles in several physiological functions such as production of saliva, gastric acid, bile, and pancreatic juice as well as in absorption of salt and water in intestine. New information suggests that these enzymes participate in several processes that were not envisioned earlier. Especially, the recent reports on plasma membrane-bound isoenzymes IX and XII have raised considerable interest since they were reported to participate in cancer invasion and spread. They are induced by tumour hypoxia and may also play a role in von Hippel-Lindau (VHL)-mediated carcinogenesis.

Carbonic Anhydrases↗

[Artificial gastrointestinal tract in gastrointestinal neoplasms].

From 1970 to 1977 an artificial gut was used in 1350 patients suffering from gastrointestinal cancer. This type of prolonged intestinal assistance was recognized to be an important adjuvant in anticancer therapy with indications prior to, during and following the traditional course of treatment. Prolonged intestinal assistance makes it possible to reestablish or maintain a biological and clinical status in patients who must undergo aggressive anticancer therapy. The indications for its use are multiplying. In 54% of the cases parenteral nutrition is associated with therapy of the curative type and this percentage is continuously increasing.

Ambulatory Care↗

Taste receptors in the gastrointestinal tract. V. Acid sensing in the gastrointestinal tract.

Luminal acidity is a physiological challenge in the foregut, and acidosis can occur throughout the gastrointestinal tract as a result of inflammation or ischemia. These conditions are surveyed by an elaborate network of acid-governed mechanisms to maintain homeostasis. Deviations from physiological values of extracellular pH are monitored by multiple acid sensors expressed by epithelial cells and sensory neurons. Acid-sensing ion channels are activated by moderate acidification, whereas transient receptor potential ion channels of the vanilloid subtype are gated by severe acidosis. Some ionotropic purinoceptor ion channels and two-pore domain background K(+) channels are also sensitive to alterations of extracellular pH.

Acid Sensing Ion Channels↗

Functions and roles of the extracellular Ca2+-sensing receptor in the gastrointestinal tract.

The gastrointestinal tract is vital to food digestion and nutrient absorption as well as normal salt and water homeostasis. Studies over the last several years have shown that the Ca2+-sensing receptor is expressed along the entire gastrointestinal tract. The potential roles for the receptor in gastrointestinal biology are now only beginning to be elucidated and much work remains. Well-studied physiological effects include regulation of gastric acid secretion and modulation of fluid transport in the colon. It remains to be determined if the Ca2+-sensing receptor is involved in calcium handling by the gastrointestinal tract. The ability of organic nutrient receptor agonists/allosteric modifiers, such as polyamines and L-amino acids, to activate the Ca2+-sensing receptor suggest potential roles in signalling nutrient availability to gastric and intestinal epithelial cells. In addition, polyamines are crucial for normal cell proliferation and differentiation required to sustain the rapid turnover of gastrointestinal epithelial cells and the Ca2+-sensing receptor may be involved in this function. Activation of the colonic Ca2+-sensing receptor can abrogate cyclic nucleotide-mediated fluid secretion suggesting a role for the receptor in modifying secretory diarrheas like cholera. Finally, the Ca2+-sensing receptor has been suggested to provide a mechanism for the effect of calcium intake in reducing the risk of colon cancer.

Animals↗

[Acute hemorrhage of the upper part of the gastrointestinal tract--survey of emergency endoscopy of the upper gastrointestinal tract at our facility].

INTRODUCTION: Acute upper gastrointestinal tract bleeding is a cause of significant morbidity and mortality and is a reason for urgent endoscopy. Besides an age and associated diseases, prognosis of patients influence also localisation and type of bleeding. The aim of our retrospective analysis was to discover causes of bleeding into upper GI tract and its characteristics over a 4 year period. METHODOLOGY: A survey of urgent upper GI tract endoscopies in the Clinic of Internal Medicine in Motol in Prague because of an acute GI tract bleeding (hematemesis or melena) was done. Found ulcers were assessed using Forrest classification. Moreover, number and causes of recurrences of bleeding were also assessed. RESULTS: Within years 1998-2001 an urgent upper GI endoscopy because of bleeding (hematemesis or melena) was done in the Clinic of Internal Medicine in Prague in Motol in 1639 patients of an average age 62.2. 56% were men (average age 59) and 44% were women (average age 65.3). An endoscopy finding without pathology was present in 21.4%. The most frequent sources of bleeding were ulcers in duodenal bulb (20%), stomach ulcers (18.2%), and hemorrhagic gastropathy (16.5%) and varices (10.3%). Results of the Forrest classification in the ulcerative disease of stomach and duodenum were as follows: Forrest Ia 9.5%, Ib 24%, IIa 14.6%, IIb 18.7%, IIc 22.9%, III 10.3%. Recurrent bleeding was identified in 8.4% of patients, thereof bleeding from esophageal varices experienced 2.9% of patients (average age 45.8), bleeding from ulcers in bulbus 2.7% (Forrest Ib, IIa a IIb) of patients of an average age 62.6, and bleeding from ulcers in stomach 2.1% (Forrest Ia, IIa a Ib) of patients of an average age 62.5. Causes of recurrent bleeding were in one case bleeding from Barrett's oesophageal ulcer and in one case bleeding from ulcer in diaphragmatic hernia. Within 48 hours recurrent bleeding appeared in 65% of patients. CONCLUSION: Urgent endoscopy in gastrointestinal tract bleeding is an essential part of a complex medical care. It is highly reliable in identifying cause of bleeding, it enables to start treatment immediately and to consider prognosis of a patient.

Acute Disease↗

Developmental microbial ecology of the neonatal gastrointestinal tract.

The gastrointestinal tract of a normal fetus is sterile. During the birth process and rapidly thereafter, microbes from the mother and surrounding environment colonize the gastrointestinal tract of the infant until a dense, complex microbiota develops. The succession of microbes colonizing the intestinal tract is most marked in early development, during which the feeding mode shifts from breast-feeding to formula feeding to weaning to the introduction of solid food. Dynamic balances exist between the gastrointestinal microbiota, host physiology, and diet that directly influence the initial acquisition, developmental succession, and eventual stability of the gut ecosystem. In this review, the development of the intestinal microbiota is discussed in terms of initial acquisition and subsequent succession of bacteria in human infants. Intrinsic and extrinsic factors influencing succession and their health significance are discussed. The advantages of modern molecular ecology techniques that provide sensitive and specific, culture-independent evaluation of the gastrointestinal ecosystem are introduced and discussed briefly. Further advances in our understanding of developmental microbial ecology in the neonatal gastrointestinal tract are dependent on the application of these modern molecular techniques.

Animals↗