How does chili cause upper gastrointestinal symptoms? A correlation study with esophageal mucosal sensitivity and esophageal motility

Personalized Treatments Based on Laryngopharyngeal Reflux Patient Profiles: A Narrative Review

OBJECTIVE

To review the current findings of the literature on the existence of several profiles of laryngopharyngeal reflux (LPR) patients and to propose personalized diagnostic and therapeutic approaches.

METHODS

A state-of-the art review of the literature was conducted using the PubMED, Scopus, and Cochrane Library databases. The information related to epidemiology, demographics, clinical presentations, diagnostic approaches, and therapeutic responses were extracted to identify outcomes that may influence the clinical and therapeutic courses of LPR.

RESULTS

The clinical presentation and therapeutic courses of LPR may be influenced by gender, age, weight, comorbidities, dietary habits and culture, anxiety, stress, and saliva enzyme profile. The clinical expression of reflux, including laryngopharyngeal, respiratory, nasal, and eye symptoms, and the hypopharyngeal-esophageal multichannel intraluminal impedance-pH monitoring profile of patients are important issues to improve in patient management. The use of more personalized therapeutic strategies appears to be associated with better symptom relief and cures over the long-term. The role of pepsin in LPR physiology is well-established but the lack of information about the role of other gastrointestinal enzymes in the development of LPR-related mucosa inflammation limits the development of future enzyme-based personalized diagnostic and therapeutic approaches.

CONCLUSION

Laryngopharyngeal reflux is a challenging ear, nose, and throat condition associated with poor therapeutic responses and a long-term burden in Western countries. Artificial intelligence should be used for developing personalized therapeutic strategies based on patient features.

Optimizing the treatment of patients with gastroesophageal reflux disease: focus on nutritional risk factors and nutritional approaches

Gastroesophageal reflux disease (GERD) is a common upper gastrointestinal disease characterized by occurrence of typical symptoms associated with an increase in esophageal acid exposure. The transient lower esophageal sphincter relaxations (TLESRs) and hypotension is the key pathophysiological mechanisms of the development of reflux disease. For a long time, it was assumed that certain nutritional and lifestyle factors affect the mechanisms of the onset and progress of GERD. However, the accumulated scientific findings show contradicting results regarding contribution of these factors to the development of reflux disease. The treatment of GERD requires lifestyle modifications, diet therapy, pharmacotherapy, and, if necessary, surgery. Proton pump inhibitors (PPIs) form the basis of pharmacotherapy. Lifestyle modifications, including dietary therapy, is also part of the treatment plan for patients with reflux symptoms, however no clear guidelines in this regard are determined due to the lack of good evidence base. Yet, while the problems associated with the long-term use of PPIs are explored, patients and physicians are increasingly interested in the role of diet in the treatment of GERD. The article provides an overview of the dietary aspects in GERD with a focus on nutritional components and their impact on the pathophysiology and treatment of this disease. Although sequential food-group elimination in GERD is common in clinical practice, literature data demonstrate a broader approach, including reduction of sugar intake, increase of dietary fibres in the diet, and changes in patterns of eating habits as a general principle.

The Spectrum of Treatment Modalities for Gastroesophageal Reflux Disease (GERD): A Narrative Review

Gastroesophageal reflux disease (GERD) is a prevalent gastrointestinal disease that is encountered and treated by physicians all over the world. It is a chronic and non-progressive condition. Symptoms can range from mild heartburn to chronic, recurrent, and severe symptoms like constant acid regurgitation, laryngitis, bad breath, otitis media, and severe heartburn, which can be debilitating to the patient. Hence, the administration of appropriate therapy according to the patient's severity of symptoms is imperative, more so because over-the-counter drugs like antacids are very common to treat GERD. Often, in some instances, mere changes in lifestyle prove highly effective in reversing GERD symptomatology. Depending on the severity, response to treatment, and presence or absence of complications, treatment with medical or surgical modalities can be decided. It has now been found that although the gold standard in medical therapy for GERD has been proton pump inhibitors (PPIs), there has been increasing research about their side effects and recurrence after treatment. Hence, newer anti-GERD drugs have been under trial, which has been discussed in detail in the review. The use of surgical fundoplications has drastically decreased and is being widely replaced by incisionless laparoscopic fundoplications and newer endoluminal techniques such as the LINX device. This review aims to compile the vast spectrum of treatment modalities for GERD, ranging from more contemporary diagnostic methods, lifestyle modifications, medical therapy, and surgical and endoluminal techniques, with a particular focus on newer directions.

Development of scores assessing the refluxogenic potential of diet of patients with laryngopharyngeal reflux

OBJECTIVE

To develop clinical tools assessing the refluxogenic potential of foods and beverages (F&B) consumed by patients with laryngopharyngeal reflux (LPR).

METHODS

European experts of the LPR Study group of the Young-Otolaryngologists of the International Federation of Oto-rhino-laryngological societies were invited to identify the components of Western European F&B that would be associated with the development of LPR. Based on the list generated by experts, four authors conducted a systematic review to identify the F&B involved in the development of esophageal sphincter and motility dysfunctions, both mechanisms involved in the development of gastroesophageal reflux disease and LPR. Regarding the F&B components and the characteristics identified as important in the development of reflux, experts developed three rational scores for the assessment of the refluxogenic potential of F&B, a dish, or the overall diet of the patient.

RESULTS

Twenty-six European experts participated to the study and identified the following components of F&B as important in the development of LPR: pH; lipid, carbohydrate, protein composition; fiber composition of vegetables; alcohol degree; caffeine/theine composition; and high osmolality of beverage. A total of 72 relevant studies have contributed to identifying the Western European F&B that are highly susceptible to be involved in the development of reflux. The F&B characteristics were considered for developing a Refluxogenic Diet Score (REDS), allowing a categorization of F&B into five categories ranging from 1 (low refluxogenic F&B) to 5 (high refluxogenic F&B). From REDS, experts developed the Refluxogenic Score of a Dish (RESDI) and the Global Refluxogenic Diet Score (GRES), which allow the assessment of the refluxogenic potential of dish and the overall diet of the LPR patient, respectively.

CONCLUSION

REDS, RESDI and GRES are proposed as objective scores for assessing the refluxogenic potential of F&B composing a dish or the overall diet of LPR patients. Future studies are needed to study the correlation between these scores and the development of LPR according to impedance-pH study.

The role of diet in the development and management of gastroesophageal reflux disease: why we feel the burn

Gastroesophageal reflux disease (GERD) is a common esophageal disorder that is characterized by troublesome symptoms associated with increased esophageal acid exposure. Cornerstones of therapy include acid suppressive agents like proton pump inhibitors (PPI) and lifestyle modifications including dietary therapy, although the latter is not well defined. As concerns regarding long term PPI use continue to be explored, patients and providers are becoming increasingly interested in the role of diet in disease management. The following is a review of dietary therapy for GERD with an emphasis on the effect food components have on pathophysiology and management. Although sequential dietary elimination of food groups is common, literature supports broader manipulation including reduction of overall sugar intake, increase in dietary fiber, and changes in overall eating practices.

Influence of capsaicin infusion on secondary peristalsis in patients with gastroesophageal reflux disease

AIM

To determine whether capsaicin infusion could influence heartburn perception and secondary peristalsis in patients with gastroesophageal reflux disease (GERD).

METHODS

Secondary peristalsis was performed with slow and rapid mid-esophageal injections of air in 10 patients with GERD. In a first protocol, saline and capsaicin-containing red pepper sauce infusions were randomly performed, whereas 2 consecutive sessions of capsaicin-containing red pepper sauce infusions were performed in a second protocol. Tested solutions including 5 mL of red pepper sauce diluted with 15 mL of saline and 20 mL of 0.9% saline were infused into the mid-esophagus via the manometric catheter at a rate of 10 mL/min with a randomized and double-blind fashion. During each study protocol, perception of heartburn, threshold volumes and peristaltic parameters for secondary peristalsis were analyzed and compared between different stimuli.

RESULTS

Infusion of capsaicin significantly increased heartburn perception in patients with GERD (P < 0.001), whereas repeated capsaicin infusion significantly reduced heartburn perception (P = 0.003). Acute capsaicin infusion decreased threshold volume of secondary peristalsis (P = 0.001) and increased its frequency (P = 0.01) during rapid air injection. The prevalence of GERD patients with successive secondary peristalsis during slow air injection significantly increased after capsaicin infusion (P = 0.001). Repeated capsaicin infusion increased threshold volume of secondary peristalsis (P = 0.002) and reduced the frequency of secondary peristalsis (P = 0.02) during rapid air injection.

CONCLUSION

Acute esophageal exposure to capsaicin enhances heartburn sensation and promotes secondary peristalsis in gastroesophageal reflux disease, but repetitive capsaicin infusion reverses these effects.

Clinical and epidemiological differences in functional dyspepsia between the East and the West

BACKGROUND

Functional dyspepsia (FD) is a common condition, affecting adults in both Western (North America and Europe) and Eastern (Asian) parts of the globe. The prevalence has been reported to range from 5% to 40%, largely due to variation from definition criteria and geographical location. Recent published reports in Western and Eastern populations separately indicate that differences in the epidemiology and clinical patterns of FD may exist. Such differences will have implications for the clinical management of and healthcare strategizing for FD at the local level.

PURPOSE

This review aims to examine the prevalence and clinical patterns of FD in specific groups, namely Western and Eastern populations, based on the Rome criteria. Further differences in the epidemiological associations of FD will be explored between population-based studies in both the East and the West. Finally, the socio-economic consequences of FD, an important measure of the impact of the disease, will be compared between the East and the West.

Influence of repeated infusion of capsaicin-contained red pepper sauce on esophageal secondary peristalsis in humans

BACKGROUND

The transient receptor potential vanilloid 1 has been implicated as a target mediator for heartburn perception and modulation of esophageal secondary peristalsis. Our aim was to determine the effect of repeated esophageal infusion of capsaicin-contained red pepper sauce on heartburn perception and secondary peristalsis in healthy adults.

METHODS

Secondary peristalsis was performed with mid-esophageal injections of air in 15 healthy adults. Two separate protocols including esophageal infusion with saline and capsaicin-contained red pepper sauce and 2 consecutive sessions of capsaicin-contained red pepper sauce were randomly performed.

KEY RESULTS

After repeated infusion of capsaicin-contained red pepper sauce, the threshold volume to activate secondary peristalsis was significantly increased during slow (p < 0.001) and rapid air injections (p = 0.004). Acute infusion of capsaicin-contained red pepper sauce enhanced heartburn perception (p < 0.001), but the intensity of heartburn perception was significantly reduced after repeated capsaicin-contained red pepper sauce infusion (p = 0.007). Acute infusion of capsaicin-contained red pepper sauce significantly increased pressure wave amplitudes of distal esophagus during slow (p = 0.003) and rapid air injections (p = 0.01), but repeated infusion of capsaicin-contained red pepper sauce significantly decreased pressure wave amplitude of distal esophagus during slow (p = 0.0005) and rapid air injections (p = 0.003).

CONCLUSIONS & INFERENCES

Repeated esophageal infusion of capsaicin appears to attenuate heartburn perception and inhibit distension-induced secondary peristalsis in healthy adults. These results suggest capsaicin-sensitive afferents in modulating sensorimotor function of secondary peristalsis in human esophagus.

Curry induces acid reflux and symptoms in gastroesophageal reflux disease

BACKGROUND

There are limited data on the effect of curry on gastroesophageal reflux disease (GERD). Our objective was to study the effects of curry on GERD.

METHODS

Symptomatic non-erosive gastroesophageal reflux disease (NERD) patients and healthy volunteers underwent ambulatory 24-h esophageal pH monitoring before consumption of either 400 or 800 ml of curry; they were monitored for 3 h thereafter for changes in esophageal pH and upper abdominal symptoms. Selected volunteers were monitored similarly after water ingestion.

RESULTS

In total, 25 NERD patients (23 males; mean age, 45 years) and 19 volunteers (13 males; mean age, 22 years) participated. In both patients and volunteers, curry ingestion induced more esophageal acid exposure than did ingestion of a similar volume of water. Curry induced significantly more esophageal acid exposure in NERD patients than in volunteers. Upper abdominal symptoms and esophageal acid exposure were more severe and persisted longer in patients than in volunteers.

CONCLUSION

Curry induced more acid reflux and caused worse symptoms in patients with NERD than in healthy individuals. Patients with NERD should be advised to avoid curry ingestion.

Clinical and epidemiological perspectives of dyspepsia in a multiracial Malaysian population

Dyspepsia is perhaps the most common gastrointestinal disease universally. The prevalence of dyspepsia ranges from 7-40% in population based studies worldwide. These figures vary with definition of dyspepsia used and also with the survey methodology. As with Western studies, functional dyspepsia (FD) predominates in Asia. With a decline in peptic ulcer disease and gastric cancer, the proportion of FD is set to increase further. Studies have shown FD to account for 50-70% of cases of uninvestigated dyspepsia. In Malaysia dyspepsia has been reported in up to 15% of a rural and 25% of an urban population. No racial differences were seen in the rural survey. In the urban survey, Malays and Indians were found to have significantly more dyspepsia than Chinese. No clear explanation can be found for these racial differences. In clinical practice, Malays seem to complain a lot of wind and bloating in the "stomach." This is interesting to note when you compare it with the prevalence of H. pylori which is distinctly less common amongst Malays compared to the Indians and Chinese. As with many Asian populations, many Malaysians do not consult for complains of dyspepsia. Many will self medicate and others may even bear with their complains. This is probably true in the rural population. Traditional medications are often used and these are often ethnic based. Different types of lotions for example are used for massaging the putative area in the abdomen by Malay, Chinese and Indian patients. Moxibustion and acupuncture is still practiced by Chinese traditional physicians for treatment of dyspepsia. The notion that mood disorders may underlies dyspepsia is still poorly accepted by a less educated or rural population who consider a psychiatric consultation a taboo. Amongst urban dwellers where Westernized medical care is readily available and the awareness of potential serious disease like cancer is higher, consultation for dyspepsia is certainly higher. Indeed a higher education level has been identified as independent risk factors for dyspepsia in both an urban and rural population survey in Malaysia. With greater consultation for dyspepsia, there has also been a higher demand and utilization of endoscopy services for investigation of gastrointestinal diseases in the country.

Effects of capsaicin-containing red pepper sauce suspension on esophageal secondary peristalsis in humans

BACKGROUND

Capsaicin-sensitive afferents have been implicated in the modulation of gastrointestinal sensorimotor functions. Secondary peristalsis is important for the clearance of retained refluxate or material from the esophagus. The aim of this study was to evaluate the effects of capsaicin-containing red pepper sauce suspension on esophageal secondary peristalsis in healthy adults.

METHODS

After a baseline recording of esophageal motility, secondary peristalsis was generated by slow and rapid mid-esophageal injections of air in 10 healthy subjects. Two separate sessions with saline and capsaicin-containing red pepper sauce were randomly performed to test their effects on esophageal secondary peristalsis.

KEY RESULTS

Infusion of capsaicin significantly increased pressure wave amplitude during rapid (P = 0.002) and slow air infusions (P = 0.01). After capsaicin, the threshold volume to generate secondary peristalsis was significantly decreased during rapid (P < 0.05) and slow air infusions (P = 0.02). Infusion of saline did not affect any parameters of secondary peristalsis during rapid or slow air infusion. The administration of capsaicin was accompanied by the occurrence of heartburn in all subjects.

CONCLUSIONS & INFERENCES

The acute administration of capsaicin-containing red pepper sauce suspension enhances sensitivity to distension-induced secondary peristalsis and facilitates secondary peristaltic contractility. These data suggest the involvement of capsaicin-sensitive afferents in the modulation of esophageal distension-induced secondary peristalsis in humans.

Risk factors associated with dyspepsia in a rural Asian population and its impact on quality of life

OBJECTIVES

The epidemiology and impact of dyspepsia in rural Asia remains uncertain. We aimed to determine the prevalence epidemiology and impact of dyspepsia in a rural Malaysian community.

METHODS

A door-to-door survey was conducted in a representative rural population in Malaysia. Dyspepsia was defined according to the Rome II criteria, and health-related quality of life (HRQOL) was assessed using the Euroqol (EQ-5D) instrument.

RESULTS

Of 2,260 adults, 2,000 (88.5%) completed the survey. The mean age of respondents was 40.4+/-15.3 years, 62.7% were women, 79.0% were ethnic Malays, 8.4% had been educated up to the tertiary level, 49.7% were unemployed, and 63.4% resided in village-type housing with 49.1% having >8 residents per household. Dyspepsia was prevalent in 292 (14.6%) adults, and they had lower mean EQ-5D utility scores compared with healthy controls (0.91+/-0.17 vs. 0.97+/-0.08, P<0.0001). Dyspepsia was found to be associated with female gender (15.8 vs. 12.7% males, P=0.058), Chinese ethnicity (19.7 vs. 14.2% non-Chinese), higher education levels, medium-range incomes (19.1% medium range vs. 13.3% low range), non-village-type housing (16.3 vs. 13.5% village-type house, P=0.08), nonsmokers (18.7 vs. 13.7%, P=0.015), non-tea drinkers (19.5 vs. 12.3%, P<0.0001), regular analgesia intake (27 vs. 12.7%, P<0.0001), and adults with chronic illness (26.6 vs. 11.1%, P<0.0001). Logistic regression analysis showed that higher levels of education, i.e., secondary (odds ratio (OR) 2.13, 95% confidence interval (CI)=1.15-3.93) and tertiary (2.70, 95% CI=1.30-5.62) education, non-village housing (OR 1.36, 95% CI=1.02-1.80), regular analgesia (OR 2.22, 95% CI=1.60-3.09), and chronic illness (OR 2.83, 95% CI=2.12-3.77) were independent risk factors for dyspepsia. Conversely, regular tea drinking (OR 0.59) seemed to have an inverse relationship.

CONCLUSIONS

Dyspepsia in rural Malaysians is associated with a lower HRQOL. Epidemiological risk factors include a higher socioeconomic status, regular analgesic consumption, and chronic illness.

Red chili induces rectal hypersensitivity in healthy humans: possible role of 5HT-3 receptors on capsaicin-sensitive visceral nociceptive pathways

BACKGROUND

Red chili has been reported to modulate visceral hypersensitivity, probably by the action of its active ingredient, capsaicin. The role of 5HT-3 receptors on capsaicin-sensitive visceral nociceptive pathways is unknown.

AIM

To test the hypothesis that capsaicin-containing red chili induces rectal hypersensitivity in healthy humans and 5HT-3 receptors participate in this effect.

METHODS

Eighteen healthy volunteers, each underwent three rectal barostat studies under three conditions: (i) oral placebo; (ii) oral chili (5 g daily x 3 days); and (iii) oral chili with 1-mg intravenous (i.v.) granisetron, in randomized, double-blinded, cross-over fashions. Rectal sensation was evaluated by using a 5-point Likert scale.

RESULTS

Chili ingestion significantly decreased rectal threshold for first, moderate and severe urgency (18 +/- 0.9, 24 +/- 1.2, and 38 +/- 1.5 mmHg, respectively) compared with placebo (22 +/- 0.9, 31 +/- 1.3, and 45 +/- 1.4 mmHg, respectively, P < 0.01). The threshold for first, moderate and severe urgency after chili with i.v. granisetron was 20 +/- 0.9, 28 +/- 1.2 and 44 +/- 1.3 mmHg, respectively. This is a significant increase compared with chili ingestion without granisetron (P < 0.05). After placebo ingestion, i.v. granisetron produced no effect on rectal sensation compared with i.v. placebo in 10 healthy volunteers (P > 0.05).

CONCLUSIONS

Low-dose granisetron, a 5HT-3 receptor antagonist, partially reversed chili-induced rectal hypersensitivity but had no effect on rectal perception induced only by mechanical balloon distention. This study suggests that 5HT-3 receptors may be involved in chili-induced rectal hypersensitivity and potentially participate in the capsaicin-sensitive nociceptive pathways of the human gut.

Gastroesophageal reflux in healthy subjects induced by two different species of chilli (Capsicum annum)

BACKGROUND

Although the ingestion of chilli has been associated with gastroesophageal reflux (GER) symptoms, there are no studies that have explored the effect of a chronic ingestion of different kinds of chilli with a variable content of capsaicin as a cause of GER.

METHODS

The effect of chilli on esophageal 24-hour pH monitoring was studied in 12 healthy subjects without GER symptoms before and after of ingestion one of two kinds of chilli. Patients were randomized to ingest 3 g daily of cascabel chilli (Capsicum annum coraciforme containing 880 ppm of capsaicin) or ancho chilli (Capsicum annum grossum containing 488 ppm of capsaicin).

RESULTS

After chilli ingestion, the Johnson De Meester Index (JDI) increased significantly [basal: 7 (1-14), after chilli: 13 (2-69), p = 0.0047]. When considering both kinds of chilli separately, the JDI varied, although nonsignificantly, with the ancho chilli [basal: 3 (1-8), after chilli: 10 (2-69), p = 0.11], and significantly with the cascabel chilli [basal: 10 (5-14), after chilli: 18 (2-44), p = 0.028].

CONCLUSION

Our results suggest that the chronic ingestion of chilli induces GER, and that the magnitude of the induced reflux seems to be related to the kind of chilli.

Sialyl Lewis X analog attenuates gastric microcirculatory disturbance and gastric mucosal erosion induced by thermal injury in rats

BACKGROUND AND AIM

We hypothesize that selectins, which are adhesion molecules, are involved in the pathogenesis of stress-induced gastropathy. We therefore investigated whether the novel Sialyl Lewis X (SLex) analog, which is a clinically available antagonist of selectins, attenuate gastric mucosal lesions induced by thermal injury.

METHODS

Male Wistar rats were anesthetized and a 30% full-skin thickness dorsal burn was inflicted on each rat. The SLex analog was administrated into the jugular vein 30 min before and 2.5 h after the thermal injury. Saline was administered to the vehicle group. The distribution of E-selectin immunoreactivity on the luminal side of the gastric mucosal microvascular network was observed by immunohistochemical methods. Active oxygen species were measured by the chemiluminescence method. Rolling leukocytes and endothelial damage, investigated by using Monastral Blue B (MBB), of the gastric mucosal microvascular network were observed through an intravital microscope.

RESULTS

A high intensity of E-selectin fluorescence was observed on the luminal surface of the venular endothelial cells 5 h after thermal injury in the vehicle group. However, E-selectin-associated fluorescence was almost negligible in the non-injury group and in the SLex analog group. The SLex analog also attenuated the rolling of leukocytes in the venules, venular deposits of MBB, luminol-dependent chemiluminescence activities, and gastric mucosal lesion formation.

CONCLUSION

It is suggested that the selectin family is involved in gastric microcirculatory disturbance and the pathogenesis of gastric mucosal lesions after thermal injury. A novel preventive therapy using the SLex analog is considered to effectively protect both gastric microcirculation and the gastric mucosa in rats with thermal injury.

Capsaicin increases gastric emptying rate in healthy human subjects measured by 13C-labeled octanoic acid breath test

The role of capsaicin-sensitive primary afferent sensory nerves in the regulation of gastrointestinal motility in human is not clarified yet. In this study, we investigated the effect of 400 microg capsaicin given intragastrically on gastric emptying measured by 13C-octanoic acid breath test in ten healthy human subjects. Four parameters of gastric emptying curves were taken into consideration: 1) maximum value of the curve, 2) time belonging to this maximum, 3) slope of the rising part of the curve and 4) time belonging to the 50% of the area under the curve. Administration of 400 microg capsaicin significantly increased the slope of gastric emptying curve (from 0.1 +/- 0.01 to 0.139 +/- 0.014 U x min(-1), P < 0.05) and significantly decreased the time belonging to the maximum value of emptying curve (from 150 +/- 18 to 75 +/- 12 min, P < 0.05) and the time belonging to the 50% of the area under the curve (from 112 +/- 15 to 99 +/- 14 min, P < 0.05). According to our results 400 microg capsaicin enhances gastric emptying rate in healthy human subjects.

A double-blind, placebo-controlled study of the efficacy and safety of non-prescription ranitidine 75 mg in the prevention of meal-induced heartburn

BACKGROUND

Ranitidine 75 mg (Zantac 75) has been shown to be effective for the treatment of pre-existing heartburn symptoms.

AIM

To compare the efficacy of dosing ranitidine 75 mg or placebo 30 min prior to a proven heartburn-provoking meal in completely preventing or reducing subsequent heartburn symptoms.

METHODS

A randomized, double-blind, parallel methodology was used at nine investigative centres. Following a screening visit, patients ate a standard test meal consisting of chili, chips and a soft drink on two occasions. On the first occasion, patients received single-blind placebo 30 min before the meal. This meal was used to qualify patients and to ensure the onset of a minimum level of heartburn. Patients who qualified were randomized (n = 284) to receive double-blind ranitidine 75 mg or placebo 30 min before a second test meal administered 4-14 days later at the treatment visit. Patients recorded whether heartburn was present and rated heartburn severity by completing visual analogue scales at 15-min intervals over the 4. 5 h meal evaluation periods.

RESULTS

Statistically significant differences favouring ranitidine 75 mg were determined for complete prevention of heartburn (P < 0.006), heartburn severity area under the curve (P < 0.001), a clinical success end-point (P < 0.001), and all other end-points (P < 0.001).

CONCLUSIONS

These data clearly demonstrate that ranitidine 75 mg is effective in completely preventing or decreasing heartburn when administered 30 min prior to a provocative meal.

Suppressed production of nitric oxide as a cause of irregular constriction of gastric venules induced by thermal injury in rats

Microcirculatory disturbance is a crucial step in development of gastric mucosal lesions. In this study we investigated the influence of nitric oxide (NO) on the irregular constriction of gastric venules observed in rats subjected to thermal injury. Male Wistar rats were anesthetized and a 30% full skin thickness dorsal burn was inflicted. Microvascular images in the submucosal layer and basal region of the gastric mucosa were obtained through an intravital microscope. Distribution of constitutive-type nitric oxide synthase (cNOS) was observed by the immunofluorescence method. Venule walls were basically smooth in the control group (no injury), whereas irregular constrictions tended to be observed in the 5-h group (5 h after thermal injury). Venule diameter was significantly smaller in the 5-h group. In the control group, cNOS-associated fluorescence was found on the venule endothelium, whereas it was almost negligible after thermal injury. A NO donor, 3-morpholinosydnonimine hydrochloride, simultaneously diminished the thermal injury-associated venule constriction and irregularity of venule walls. Therefore, the present study suggests that venule constriction, which is observed 5 h after thermal injury, is related to decreased NO production by endothelial cNOS and is a cause of irregularity of the venule walls.

A protease inhibitor attenuates gastric erosions and microcirculatory disturbance in the early period after thermal injury in rats

The effects of camostat mesilate, a synthetic serine protease inhibitor on gastric microcirculation and active oxygen species generated by leucocytes from the gastric and jugular veins in the early period after thermal injury were assessed. Male Wistar rats were anaesthetized and a 30% full skin-thickness dorsal burn was inflicted. Camostat mesilate (100 mg/kg) was dissolved in distilled water and administered orally to rats 40 min before thermal injury (the camostat group). The control animals (the vehicle group) were administered distilled water orally. Rolling leucocytes as well as Monastral blue B deposits in venules were observed using in vivo microscopy. Active oxygen species were measured by chemiluminescence. Camostat mesilate decreased the total length of gastric erosion, venular deposits of Monastral blue B, and rolling of leucocytes in venules, and relatively increased luminol-dependent chemiluminescence activity generated by zymosan-stimulated leucocytes 15 min after thermal injury. These results suggest that serine proteases are involved in the formation of gastric erosions and gastric microcirculatory disturbance in the early period after thermal injury.

Up-regulation of oxygen-derived free radicals by interleukin-1 in hepatic ischemia/reperfusion injury

BACKGROUND

Oxygen-derived free radicals (FRs) are critical mediators of ischemia/reperfusion injury. Inflammatory cytokines have been shown to play important roles in tissue injury. To examine the relationship between FRs and interleukin-1 (IL-1) in hepatic ischemia/reperfusion injury, we used interleukin-1 receptor antagonist (IL-1ra) to block endogenous IL-1 production in a rat model of hepatic ischemia/reperfusion.

METHODS

Female SD rats were subjected to 30 min of hepatic ischemia followed by reperfusion. The animals were divided into two groups, control group and IL-1ra-treated group, according to the rinse solution. In both groups, FR production, histological changes, and interactions between leukocytes and endothelial cells were analyzed in the course of reperfusion.

RESULTS

In the control group, production of FRs increased significantly after 60 min of reperfusion. After 60 and 180 min of reperfusion, histological examination showed atrophy and degeneration of hepatocytes. Hepatic microcirculation demonstrated a marked increase in the number of leukocytes adherent to endothelial cells and of injured cells after reperfusion. In the IL-1ra-treated group, IL-1ra pretreatment markedly reduced FR production after 60 min of reperfusion, the number of leukocytes adherent to endothelial cells, and tissue injury.

CONCLUSION

These data clearly show an important role for IL-1 in the induction of FR production, leukocyte adhesion, and tissue injury after hepatic ischemia/reperfusion injury.