Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0847097 (acidity)
 15,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gastroesophageal reflux disease (GERD) is a common chronic disorder in the Western world. The basic cause of GERD has been well characterized--the fundamental defect is a loss of integrity of the gastroesophageal barrier. What is less clear is the most appropriate means of addressing this reflux. GERD has a variety of symptoms, ranging from typical presentations of heartburn and regurgitation (without esophagitis) to atypical presentations, such as severe erosive esophagitis and its associated complications. Because of its symptomatic diversity, physicians may select from a variety of therapeutic approaches. Medical therapy aims at decreasing acidity by suppressing proton secretion and has been well established. Available medications include antacids and alginates, H2-receptor antagonists, motility agents, and proton pump inhibitors (PPIs). Antireflux surgery, commonly performed laparoscopically, aims at reinforcing and repairing the defective barrier through plication of the gastric fundus. The earliest performed successful procedures were the Nissen and Toupet fundoplications, to which several modifications have since been made. It has been demonstrated in preliminary studies and long-term outcomes of such open surgery and preliminary studies of such laparoscopic surgery that antireflux surgery is an effective approach, with overall outcomes superior to those achieved with medications. The precise indications for the surgical treatment of patients with GERD, however, remain controversial. In recent years, endoscopic intraluminal antireflux approaches have attracted the attention of physicians, surgeons, and commercial companies, especially after the approval of two endoscopic intraluminal methods by the United States FDA in 2000. The common element is prevention of acid reflux by construction of a functional or controlled barrier in the lower esophageal sphincter zone. Three main methods are currently employed: endoscopic intraluminal valvuloplasty, endoscopic radiofrequency therapy, and endoscopic injection or implantation of foreign material. The endoluminal suturing method is highly demanding technically, and its short-term results are encouraging, although largely dependent on the experience of the endoscopist. Several prospective cohort studies have shown that the radiofrequency procedure (Stretta) significantly improves GERD symptoms and quality of life while reducing esophageal acid exposure and eliminating the need for antisecretory medications in the majority of patients within 6-12 months. Most recently, some researchers have studied the endoluminal implantation of polymers, such as Plexiglas (polymethyl-methylacrylate), Gatekeeper hydrogel, and Enteryx (ethylene vinyl alcohol copolymer). The preliminary results of these studies showed that the implantation method was feasible and safe; however, the only multicenter trial related to outcome that has been published has included just 1 year of follow-up. Here, we review the treatment of GERD: medical, surgical, and endoscopic. In addition, we provide an algorithm based on symptoms and response to treatment for management of these patients.
 ...
PMID:Management of gastroesophageal reflux disease: medications, surgery, or endoscopic therapy? (Current status and trends). 1602 48

Inhibitors of gastric acid secretion are efficient drugs in the treatment of acid-related diseases. However, by reducing gastric acidity, hypergastrinemia develops. Gastrin regulates its target cell, the enterochromaffin (ECL) cell, both functionally and tropicaly. Long-term hypergastrinemia in whatever species studied, has been shown to induce tumors originating from the ECL cell. In man, at least 10 years of hypergastrinemia, accompanied by high or reduced gastric acidity is necessary to induce ECL cell carcinoids. There are reports indicating development of ECL cell carcinoids after long-term treatment with proton pump inhibitors. Moreover, the ECL cell may give rise to gastric carcinomas of diffuse type, which have increased during the last decades. Furthermore, most of the carcinomas developing in patients with long-lasting hypergastrinemia are of ECL cell origin. Therefore, long-lasting iatrogenic hypergastrinemia induced by potent inhibitors of acid secretion may be expected to increase the occurrence of gastric carcinomas in the future.
 ...
PMID:Antiulcer drugs and gastric cancer. 1618 20

In his Perspective, Grebe discusses how a plant proton pump residing in intracellular compartments, rather than in the plasma membrane of the cell surface, regulates growth and development. The pump modulates the expression at the plasma membrane of both a transporter for the hormone auxin and another proton pump. These findings open new views on how plants regulate cell wall acidity and hormone transport during development.
 ...
PMID:Plant biology. Enhanced: growth by auxin: when a weed needs acid. 1648 79

Immediate-release omeprazole (Zegerid, Santarus) is the first immediate-release oral proton pump inhibitor to reach the market. As a powder formulation for oral suspension, it is indicated for the treatment of gastroesophageal reflux disease, erosive oesophagitis, duodenal ulcer and gastric ulcer, and is the only proton pump inhibitor approved for the reduction of risk of upper gastrointestinal bleeding in critically ill patients. Administration of immediate-release omeprazole at bedtime results in a rapid and sustained elevation of gastric pH, and seems to provide better night time control of gastric acidity than that observed with conventional morning dosing of delayed-release proton pump inhibitors. The immediate-release formulation may provide a good treatment option for patients who require flexible dosing, quick onset of action and nocturnal gastric acid control.
 ...
PMID:Review of immediate-release omeprazole for the treatment of gastric acid-related disorders. 1625 81

Gastroesophageal reflux disease (GERD) is a chronic disease affecting up to 40% of people in the Western world. Risk factors associated with GERD include age and lifestyle habits, although the clinically relevant contribution of many of these factors is unclear. In GERD, refluxed gastric acid damages the oesophageal mucosa, generally when the pH falls below 4. GERD patients present a variety of symptoms, most commonly heartburn and regurgitation. Oesophageal complications associated with GERD include erosions, ulcers, peptic strictures, and Barrett's oesophagus which is implicated in the development of oesophageal adenocarcinoma. Diagnosis of GERD is problematic due to the range of symptoms which may be presented to the physician and symptom severity is frequently unrelated to disease severity. While endoscopic monitoring may be used to assess the presence and severity of GERD, a lack of visible damage does not necessarily indicate an absence of GERD. Techniques used to diagnose GERD include addition of an acid solution into the oesophagus in order to replicate symptoms (Bernstein test) or 24-hour intra-oesophageal pH monitoring. Proton pump inhibitors are effective in the treatment of GERD, acting to reduce the acidity of the gastric juice and hence reduce oesophageal damage and symptoms associated with GERD. Symptoms most indicative of GERD are those associated with erosive oesophagitis, including heartburn and acid regurgitation. Less common GERD-associated symptoms include chest pain, a range of ear, nose and throat conditions, and asthma. In contrast to perceptions of the disease as 'merely' heartburn, the impact on patients' quality of life can be profound. Increasing awareness of GERD by health care professionals has led to improved diagnosis and a greater appreciation of the need for maintenance therapy.
 ...
PMID:Gastroesophageal reflux disease: clinical features. 1634 49

Proton pump inhibitors (PPIs) are used widely in the management of acid-related disorders and, for the majority of patients, oral therapy is highly effective. Not all patients with acid-related disorders respond completely to standard, once-daily PPI therapy, but most nonresponders will generally respond to an increase in the dose or frequency of PPI therapy. At equivalent doses, oral and intravenous (IV) PPIs produce comparable acid suppression; thus there are very few clinical indications for IV PPI therapy. IV PPIs are an appropriate substitute for oral PPIs, at an equivalent dose, for patients with, for example, gastroesophageal reflux disease, peptic ulceration, or Zollinger-Ellison syndrome, who cannot take oral medication. For patients with nonvariceal, upper gastrointestinal hemorrhage, profound acid suppression (gastric pH . 6.0) optimizes clot stability and reduces the risk of rebleeding; this is achieved most effectively with an initial IV PPI bolus followed by a continuous infusion. High-dose, IV PPI therapy is beneficial and cost-effective in patients who have a high-risk lesion at endoscopy and it should be preceded by effective endoscopic hemostasis if possible. IV PPIs, preoperatively and in the intensive care setting, effectively reduce gastric acidity, but there are no convincing data that this confers any significant clinical benefit compared with other therapeutic strategies.
 ...
PMID:Intravenous proton pump inhibitor therapy: a rationale for use. 1636 24

No evidence supports one method over another in managing uncomplicated gastroesophageal reflux disease (GERD) for patients aged >65 years. For those with endoscopically documented esophagitis, proton pump inhibitors (PPIs) relieve symptoms faster than histamine H2 receptor antagonists (H2RAs) (strength of recommendation [SOR]: B, extrapolation from randomized controlled trials [RCTs]). Treating elderly patients with pantoprazole (Protonix) after resolution of acute esophagitis results in fewer relapses than with placebo (SOR: B, double-blind RCT). Limited evidence suggests that such maintenance therapy for prior esophagitis with either H2RAs or PPIs, at half- and full-dose strength, decreases the frequency of relapse (SOR: B, extrapolation from uncontrolled clinical trial). Laparoscopic antireflux surgery for treating symptomatic GERD among elderly patients without paraesophageal hernia reduces esophageal acidity, with no apparent increase in postoperative morbidity or mortality compared with younger patients (SOR: C, nonequivalent before-after study). Upper endoscopy is recommended for elderly patients with alarm symptoms, new-onset GERD, or longstanding disease (SOR: C, expert consensus). Elderly patients are at risk for more severe complications from GERD, and their relative discomfort from the disease process is often less than from comparable pathology for younger patients (SOR: C, expert consensus). Based on safety profiles and success in the general patient population, PPIs as a class are considered first-line treatment for GERD and esophagitis for the elderly (SOR: C, expert consensus).
 ...
PMID:What is the best way to manage GERD symptoms in the elderly? 1651 61

Tumor microenvironment may play a key role in tumor malignancy. It is hypothesized that hypoxia and acidity may contribute to the progression from benign to malignant growth. In particular, the unfavorable environment may induce the selection of tumor cells able to survive in acidic and hypoxic conditions. In fact, the common components of the cancer phenotype result from active selection, and characteristics of tumor microenvironment may create the best condition for this selection. Acidity, in particular, has been shown to have a role in resistance to chemotherapy, proliferation and metastatic behavior. In fact, a mechanism of resistance to cytotoxic drugs may be the alteration of the tumor microenvironment through changes of the pH gradient between the extracellular environment and cell cytoplasm. The extracellular pH of solid tumors is significantly more acidic than that of normal tissues, thus impairing the uptake of weakly basic chemotherapeutic drugs and reducing their effect on tumors. An important determinant of tumor acidity is the anaerobic metabolism that allows selection of cells able to survive in an hypoxic-anoxic environment with the generation of lactate. However, this is not the major mechanism responsible for the development of an acidic environment within solid tumors. It appears clear that a complex framework of protein-protein, protein-lipid and lipid-lipid interactions underlay the pH homeostasis in mammalian cells. Malignant tumor cells seem to hijack some of these mechanism to protect themselves from the acidic environment and to maintain acidity in an environment unsuitable for normal or more differentiated cells. Recent data suggest that vacuolar-type (V-type) H(+)-ATPases, that pump protons across the plasma membrane, may have a key role in the acidification of the tumor microenvironment. Some human tumor cells are characterized by an increased V-type H(+)-ATPase expression and activity, and pretreatment with proton pump inhibitors -- a class of H(+)-ATPase inhibitors -- sensitized tumor cell lines to the effect of a variety of anticancer drugs. Proton pump inhibitor pretreatment has been associated with inhibition of V-type H(+)-ATPase activity and increase in both extracellular pH and pH of lysosomal organelles. In vivo experiments in human/mouse xenografts have shown that oral pretreatment with proton pump inhibitors is able to sensitize human solid tumors to anticancer drugs. These data suggest that tumor alkalinization may represent a key target of future antitumor strategies.
 ...
PMID:Tumor acidity, chemoresistance and proton pump inhibitors. 1655 57

The dramatic success of pharmacological acid suppression in healing peptic ulcers and managing patients with gastroesophageal reflux disease (GERD) has been reflected in the virtual abolition of elective surgery for ulcer disease, a reduction in nonsteroidal anti-inflammatory drug (NSAID)-associated gastropathy and the decision by most patients with reflux symptoms to continue medical therapy rather than undergo surgical intervention. However, a number of challenges remain in the management of acid-related disorders. These include management of patients with gastroesophageal symptoms who do not respond adequately to proton pump inhibitor (PPI) therapy, treatment of patients with nonvariceal upper gastrointestinal bleeding, prevention of stress-related mucosal bleeding, optimal treatment and prevention of NSAID-related gastrointestinal injury, and optimal combination of antisecretory and antibiotic therapy for the eradication of Helicobacter pylori infection. A number of new drugs are currently being investigated to provide a significant advance on current treatments. Some of them (namely potassium-competitive acid blockers (P-CABs) and CCK2-receptor antagonists) have already reached clinical testing while some others (like the antigastrin vaccine, H3-receptor ligands or gastrin-releasing peptide receptor antagonists) are still in preclinical development and need the proof of concept in human beings. Of the current approaches to reduce acid secretion, P-CABs and CCK2-receptor antagonists hold the greatest promise, with several compounds already in clinical trials. Although the quick onset of action of P-CABs (i.e. a full effect from the first dose) is appealing, the results of phase II studies with one such agent (namely AZD0865) did not show any advantages over esomeprazole. Thanks to their limited efficacy and the development of tolerance it is unlikely that CCK2 antagonists will be used alone as antisecretory compounds but, rather, their combination with PPIs will be attempted with the aim of reducing the long-term consequences of hypergastrinemia. While H2-receptor antagonists (especially soluble or over-the-counter formulations) will become the 'antacids of the third millennium' and will be particularly useful for on-demand symptom relief, clinicians will continue to rely on PPIs to control acid secretion in GERD and other acid-related diseases. In this connection, several new PPI formulations have been developed and two novel drugs (namely ilaprazole and tenatoprazole) are being studied in humans. The recently introduced immediate-release (IR) omeprazole formulation (currently available only in the USA) quickly increases intragastric pH and, given at bedtime, seems to achieve a better control of nocturnal acidity. IR formulations of other PPIs (including the investigational ones) will probably be available in the future and will enlarge our therapeutic armamentarium. Amongst the novel PPIs, tenatoprazole appears to be a true advance in the acid suppression therapy. Its long half-life (the longest among the available compounds) and longer duration of antisecretory action, with no difference between day and night, will allow the drug to go beyond the intrinsic limitations of currently available PPIs. Thanks to its favorable pharmacokinetics, the sodium salt of S-tenatoprazole is being developed and the preliminary results indicate that this drug has the potential to address unmet clinical needs. Although some decades have elapsed since the introduction of effective and safe antisecretory drugs in clinical practice and their use has stood the test of time, the ongoing research will further provide the clinician with more effective means of controlling acid secretion.
 ...
PMID:Acid suppression therapy: where do we go from here? 1669 62

Acid suppression therapy with proton pump inhibitors is associated with well-established benefits in the management of gastro-oesophageal reflux (GERD) and other acid-related disorders. However, a number of issues still remain unsettled. Despite their clinical efficacy, when given once daily, currently available proton pump inhibitors may not adequately control intragastric acidity during the night in a significant proportion of both healthy subjects and GERD patients, in whom symptom relief remains suboptimal. Although some novel proton pump inhibitors have been synthesized, only few reached clinical testing. Amongst them, tenatoprazole represents a true advance displaying a long half-life (five to seven times longer than that of currently available drugs) and extended acid suppression covering both day and night. All the available clinical studies suggest both pharmacokinetic and pharmacodynamic advantages of tenatoprazole over esomeprazole. As this last compound provides - amongst the members of the class - the most effective control of intragastric pH whatever the parameter considered, it is conceivable that tenatoprazole could similarly be better than the other existing proton pump inhibitors. Tenatoprazole appears to be a promising proton pump inhibitor for the treatment of acid-related diseases, where it has the potential to address unmet clinical needs.
 ...
PMID:Review article: the opportunities and benefits of extended acid suppression. 1670 Sep


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>