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Nutrients Mar 2010Vitamin B(12) is essential for DNA synthesis and for cellular energy production.This review aims to outline the metabolism of vitamin B(12), and to evaluate the causes... (Review)
Review
Vitamin B(12) is essential for DNA synthesis and for cellular energy production.This review aims to outline the metabolism of vitamin B(12), and to evaluate the causes and consequences of sub-clinical vitamin B(12) deficiency. Vitamin B(12) deficiency is common, mainly due to limited dietary intake of animal foods or malabsorption of the vitamin. Vegetarians are at risk of vitamin B(12) deficiency as are other groups with low intakes of animal foods or those with restrictive dietary patterns. Malabsorption of vitamin B(12) is most commonly seen in the elderly, secondary to gastric achlorhydria. The symptoms of sub-clinical deficiency are subtle and often not recognized. The long-term consequences of sub-clinical deficiency are not fully known but may include adverse effects on pregnancy outcomes, vascular, cognitive, bone and eye health.
Topics: Absorption; Biomarkers; Cardiovascular Diseases; Cognition Disorders; Female; Food; Humans; Male; Neural Tube Defects; Nutritional Requirements; Osteoporosis; Pregnancy; Pregnancy Complications; Vitamin B 12; Vitamin B 12 Deficiency
PubMed: 22254022
DOI: 10.3390/nu2030299 -
Acta Bio-medica : Atenei Parmensis Dec 2018Although the actual prevalence of chronic atrophic gastritis is unknown and it is probable that this entity goes largely underdiagnosed, patients in whom diagnosis is... (Review)
Review
Although the actual prevalence of chronic atrophic gastritis is unknown and it is probable that this entity goes largely underdiagnosed, patients in whom diagnosis is established usually present advanced stages of disease. Destruction of parietal cells, either autoimmune-driven or as a consequence of Helicobacter pylori infection, determines reduction or abolition of acid secretion. Hypo/achloridia causes an increase in serum gastrin levels, with an increased risk of the development of neuroendocrine tumors. Microcytic, hypochromic anemia frequently precedes the development of megaloblastic, vitamin B12-associated anemia. Moreover, vitamin B12 deficiency,may cause elevation of homocysteine, with an increase in the cardiovascular risk, and may be associated with neurological manifestations, mainly characterized by spinal cord demyelination and atrophy, with ensuing sensory-motor abnormalities. Gastrointestinal manifestations seem to be associated with non-acid reflux and tend to be non-specific.
Topics: Achlorhydria; Anemia, Pernicious; Autoimmune Diseases; Chronic Disease; Demyelinating Diseases; Gastritis, Atrophic; Helicobacter Infections; Helicobacter pylori; Humans; Hyperhomocysteinemia; Parietal Cells, Gastric; Symptom Assessment
PubMed: 30561424
DOI: 10.23750/abm.v89i8-S.7921 -
World Journal of Gastroenterology Jun 2010Human intestinal microbiota create a complex polymicrobial ecology. This is characterised by its high population density, wide diversity and complexity of interaction.... (Review)
Review
Human intestinal microbiota create a complex polymicrobial ecology. This is characterised by its high population density, wide diversity and complexity of interaction. Any dysbalance of this complex intestinal microbiome, both qualitative and quantitative, might have serious health consequence for a macro-organism, including small intestinal bacterial overgrowth syndrome (SIBO). SIBO is defined as an increase in the number and/or alteration in the type of bacteria in the upper gastrointestinal tract. There are several endogenous defence mechanisms for preventing bacterial overgrowth: gastric acid secretion, intestinal motility, intact ileo-caecal valve, immunoglobulins within intestinal secretion and bacteriostatic properties of pancreatic and biliary secretion. Aetiology of SIBO is usually complex, associated with disorders of protective antibacterial mechanisms (e.g. achlorhydria, pancreatic exocrine insufficiency, immunodeficiency syndromes), anatomical abnormalities (e.g. small intestinal obstruction, diverticula, fistulae, surgical blind loop, previous ileo-caecal resections) and/or motility disorders (e.g. scleroderma, autonomic neuropathy in diabetes mellitus, post-radiation enteropathy, small intestinal pseudo-obstruction). In some patients more than one factor may be involved. Symptoms related to SIBO are bloating, diarrhoea, malabsorption, weight loss and malnutrition. The gold standard for diagnosing SIBO is still microbial investigation of jejunal aspirates. Non-invasive hydrogen and methane breath tests are most commonly used for the diagnosis of SIBO using glucose or lactulose. Therapy for SIBO must be complex, addressing all causes, symptoms and complications, and fully individualised. It should include treatment of the underlying disease, nutritional support and cyclical gastro-intestinal selective antibiotics. Prognosis is usually serious, determined mostly by the underlying disease that led to SIBO.
Topics: Blind Loop Syndrome; Breath Tests; Diagnosis, Differential; Humans; Intestine, Small; Prognosis
PubMed: 20572300
DOI: 10.3748/wjg.v16.i24.2978 -
International Journal of Molecular... Oct 2019The use of proton pump inhibitors (PPIs) over the last 30 years has rapidly increased both in the United States and worldwide. PPIs are not only very widely used both... (Review)
Review
The use of proton pump inhibitors (PPIs) over the last 30 years has rapidly increased both in the United States and worldwide. PPIs are not only very widely used both for approved indications (peptic ulcer disease, gastroesophageal reflux disease (GERD), Helicobacter pylori eradication regimens, stress ulcer prevention), but are also one of the most frequently off-label used drugs (25-70% of total). An increasing number of patients with moderate to advanced gastroesophageal reflux disease are remaining on PPI indefinitely. Whereas numerous studies show PPIs remain effective and safe, most of these studies are <5 years of duration and little data exist for >10 years of treatment. Recently, based primarily on observational/epidemiological studies, there have been an increasing number of reports raising issues about safety and side-effects with very long-term chronic treatment. Some of these safety issues are related to the possible long-term effects of chronic hypergastrinemia, which occurs in all patients taking chronic PPIs, others are related to the hypo-/achlorhydria that frequently occurs with chronic PPI treatment, and in others the mechanisms are unclear. These issues have raised considerable controversy in large part because of lack of long-term PPI treatment data (>10-20 years). Zollinger-Ellison syndrome (ZES) is caused by ectopic secretion of gastrin from a neuroendocrine tumor resulting in severe acid hypersecretion requiring life-long antisecretory treatment with PPIs, which are the drugs of choice. Because in <30% of patients with ZES, a long-term cure is not possible, these patients have life-long hypergastrinemia and require life-long treatment with PPIs. Therefore, ZES patients have been proposed as a good model of the long-term effects of hypergastrinemia in man as well as the effects/side-effects of very long-term PPI treatment. In this article, the insights from studies on ZES into these controversial issues with pertinence to chronic PPI use in non-ZES patients is reviewed, primarily concentrating on data from the prospective long-term studies of ZES patients at NIH.
Topics: Animals; Carcinoma, Neuroendocrine; Chronic Disease; Gastrinoma; Gastrins; Humans; Proton Pump Inhibitors; Risk Factors; Stomach Diseases; Time Factors; Treatment Outcome; Zollinger-Ellison Syndrome
PubMed: 31623145
DOI: 10.3390/ijms20205128 -
International Journal of Molecular... Sep 2020is a class one carcinogen which causes chronic atrophic gastritis, gastric intestinal metaplasia, dysplasia and adenocarcinoma. The mechanisms by which interacts with... (Review)
Review
is a class one carcinogen which causes chronic atrophic gastritis, gastric intestinal metaplasia, dysplasia and adenocarcinoma. The mechanisms by which interacts with other risk and protective factors, particularly vitamin C in gastric carcinogenesis are complex. Gastric carcinogenesis includes metabolic, environmental, epigenetic, genomic, infective, inflammatory and oncogenic pathways. The molecular classification of gastric cancer subtypes has revolutionized the understanding of gastric carcinogenesis. This includes the tumour microenvironment, germline mutations, and the role of bacteria, virus and epigenetics in somatic mutations. There is evidence that ascorbic acid, phytochemicals and endogenous antioxidant systems can modify the risk of gastric cancer. Gastric juice ascorbate levels depend on dietary intake of ascorbic acid but can also be decreased by infection, CagA secretion, tobacco smoking, achlorhydria and chronic atrophic gastritis. Ascorbic acid may be protective against gastric cancer by its antioxidant effect in gastric cytoprotection, regenerating active vitamin E and glutathione, inhibiting endogenous N-nitrosation, reducing toxic effects of ingested nitrosodimethylamines and heterocyclic amines, and preventing infection. The effectiveness of such cytoprotection is related to strain virulence, particularly CagA expression. The role of vitamin C in epigenetic reprogramming in gastric cancer is still evolving. Other factors in conjunction with vitamin C also play a role in gastric carcinogenesis. Eradication of may lead to recovery of vitamin C secretion by gastric epithelium and enable regression of premalignant gastric lesions, thereby interrupting the Correa cascade of gastric carcinogenesis.
Topics: Animals; Antioxidants; Ascorbic Acid; Carcinogenesis; Gastric Juice; Helicobacter Infections; Helicobacter pylori; Humans; Phytochemicals; Stomach Neoplasms
PubMed: 32899442
DOI: 10.3390/ijms21176451 -
Romanian Journal of Morphology and... 2017Chronic diarrhea in infants is a common condition for addressability to pediatric gastroenterologists. The causes are multiple and the delay in reaching the final... (Review)
Review
Chronic diarrhea in infants is a common condition for addressability to pediatric gastroenterologists. The causes are multiple and the delay in reaching the final diagnosis can lead to complications in the general condition of the child. The purpose of this review is to present the bio-clinical and histogenetic particularities of a rare clinical entity, characterized by tumoral causes of chronic diarrhea. VIPomas are neuroendocrine tumors that autonomously secrete vasoactive intestinal peptide (VIP). Watery diarrhea, hypokalemia and achlorhydria (WDHA) syndrome caused by VIP-producing tumors only rarely occurs in adult patients with non-pancreatic disease. In pediatric patients, it is extremely rare for a VIPoma to originate in the pancreas; instead, WDHA syndrome is usually associated with VIP-secreting neurogenic tumors involving the retroperitoneum or mediastinum. The majority of VIP secreting tumors in pediatric patients are represented by ganglioneuroblastomas or ganglioneuromas originating in the adrenal medulla or sympathetic neural crest. This syndrome of watery diarrhea associated with hypokalemia and achlorhydria was first described by Verner and Morrison, in 1958, and has been assumed to be due to hypersecretion of VIP. In children, as well as in adult patients, the most likely explanation for persistent secretory diarrhea may be an occult VIPoma. In conclusion, the physicians should be aware that there are some rare tumoral causes of chronic diarrhea, often under-diagnosed. If the diagnosis is not considered, extensive gastrointestinal investigations will be undertaken, delaying the diagnosis and avoidable morbidity will occur.
Topics: Ganglioneuroma; Humans; Vasoactive Intestinal Peptide; Vipoma
PubMed: 28730220
DOI: No ID Found