Fifty million years of herbivory on coral reefs: fossils, fish and functional innovations.

The evolution of ecological processes on coral reefs was examined based on Eocene fossil fishes from Monte Bolca, Italy and extant species from the Great Barrier Reef, Australia. Using ecologically relevant morphological metrics, we investigated the evolution of herbivory in surgeonfishes (Acanthuridae) and rabbitfishes (Siganidae). Eocene and Recent surgeonfishes showed remarkable similarities, with grazers, browsers and even specialized, long-snouted forms having Eocene analogues. These long-snouted Eocene species were probably pair-forming, crevice-feeding forms like their Recent counterparts. Although Eocene surgeonfishes likely played a critical role as herbivores during the origins of modern coral reefs, they lacked the novel morphologies seen in modern Acanthurus and Siganus (including eyes positioned high above their low-set mouths). Today, these forms dominate coral reefs in both abundance and species richness and are associated with feeding on shallow, exposed algal turfs. The radiation of these new forms, and their expansion into new habitats in the Oligocene-Miocene, reflects the second phase in the development of fish herbivory on coral reefs that is closely associated with the exploitation of highly productive short algal turfs.

Pair formation in the herbivorous rabbitfish Siganus doliatus.

This study investigated the basis of pair formation in the abundant herbivorous rabbitfish Siganus doliatus on Orpheus Island, Great Barrier Reef. Pair formation was the most common social system in S. doliatus, with 67.4% of all individuals occurring in pairs. Pairs were stable (i.e. individuals remained with the same partner throughout the study) and pair members were found within 5 m of each other 82.9% of the time. Of the examined pairs, 25% were homosexual resulting in a proportion of heterosexual pairs (75%) that was significantly lower than expected if pairs were formed solely for reproductive reasons. Therefore, although reproduction appears to be the main driver of pair formation in S. doliatus, other factors are likely to influence this behaviour. The high density of individuals on the reef crest (5.7 ± 0 .9 individuals 200 m(-2); mean ± s.e.) and extensively overlapping home ranges of pairs indicated that the defence of territories plays no role in pair formation. Instead, it appears that pair formation in S. doliatus is driven, in part, by other, non-reproductive, ecological factors. It is suggested that pair formation allows for increased vigilance against predation and enables S. doliatus to execute a novel feeding behaviour.

Prevalence and severity of foot pad alterations in German turkey poults during the early rearing phase.

In the previously performed field study from 2007 to 2009, it became evident that foot pad alterations were already commonly found in turkeys at the age of 6 wk. At this early age, 45% of the clinically examined birds were diagnosed with epithelial necrosis. Therefore, it became important to specifically analyze the situation during the early rearing phase. The present study reflects the prevalence and severity of foot pad alterations of turkey poults up to the age of 35 d (5 wk), starting as early as the age of 3 d. From 24 turkey farms throughout Germany, in general 5,531 turkeys [3,131 male and 2,400 female] of the British United Turkeys 6 strain from 46 flocks, were examined to that effect. Prevalence and severity increased within the duration of stay in the stable, and the prevalence was higher (P < 0.001) during the second visit between d 22 to 35 (factor: 0.94). Therefore, 27.3% (d 3 to 5; male/female: 39.1/25.0%) and 63.3% (d 22 to 35: 61.3/65.7%) of the examined poults had alterations of the foot pads, such as hyperkeratosis (d 3 to 5: 20.4/14.2%; d 22 to 35: 17.6/17.1%), high-grade hyperkeratosis with adhesive dirt (d 3 to 5: 8.7/10.7%; d 22 to 35: 29.2/39.3%), and epithelial necrosis (d 3 to 5: 0.1/0.1%; d 22 to 35: 14.6/9.3%). Female poults showed a higher risk (P < 0.001) of developing food pad alterations (factor: 0.76) than male poults. Male poults developed a higher percentage of epithelial necrosis than hens shortly before relocation. A higher stocking density during the very early rearing phase (d 3 to 5) led to a worse foot pad health status (P < 0.001). Because even mild alterations in the foot pad condition can be indicators for suboptimal design of the rearing environment and are to be seen as a pre-state for severe cases of foot pad dermatitis, it is important to set the main focus on the early rearing phase.

Omeprazole enhances efficacy of triple therapy in eradicating Helicobacter pylori.

Triple therapy has been recommended as the most effective treatment for Helicobacter pylori eradication. Despite achieving a comparatively high eradication result, however, around 10% of patients still fail to be cured. Omeprazole can enhance efficacy of single and double antibiotic protocols and is particularly effective when combined with clarithromycin and a nitroimidazole. This study examined the effect of combining triple therapy with omeprazole. A prospective, randomised, unblinded, single centre trial was carried out on consecutive patients with symptoms of dyspepsia and H pylori infection confirmed by rapid urease test, microbiological culture, and histological assessment. Patients were given a five times/day, 12 day course of colloidal bismuth subcitrate chewable tablets (108 mg), tetracycline HCl (250 mg), and metronidazole (200 mg) with either 20 mg omeprazole twice daily (triple therapy+omeprazole) or 40 mg famotidine (triple therapy+famotidine) at night. Compliance and side effects were determined using a standard questionnaire form. One hundred and twenty five of 165 triple therapy+omeprazole patients and 124 of 171 triple therapy+famotidine patients returned for rebiopsy four weeks after completion of treatment. Significantly more triple therapy+omeprazole patients achieved eradication 122 of 125 (97.6%) as assessed by negative urease test, culture, and histological assessment, when compared with 110 of 124 (89%) triple therapy+famotidine patients (p = 0.006; chi 2). There were 30 triple therapy+omeprazole (24%) and 26 triple therapy+famotidine (21%) patients with de novo metronidazole resistant H pylori included in the study. Side effects were mild and infrequent and were comparable in both groups, although pain in duodenal ulcer, gastric ulcer, and oesophagitis patients seemed to subside earlier in those taking omeprazole. Compliance (>95% of drugs taken) was achieved by 98% of patients of both groups. A 12 days regimen of triple therapy with omeprazole is more effective in achieving H pylori eradication than is triple therapy plus famotidine. Use of 20 mg omeprazole twice daily rather than 40 mg famotidine with a 12 day, low dose triple therapy enhances eradication to over 97% whether the H pylori is metronidazole sensitive or resistant.

Helicobacter pylori reinfection rate, in patients with cured duodenal ulcer.

OBJECTIVE: To determine the reinfection rate of the gastric mucosa in patients previously cured of duodenal ulcers, following the eradication of Helicobacter pylori. Only those remaining H. pylori-negative beyond 12 months of follow-up were studied, to minimize the potential inclusion of patients with H. pylori recrudescence. METHODS: Patients with endoscopically proven duodenal ulcers who had been treated with triple therapy, resulting in documented eradication of H. pylori and cure of the ulcer for at least 4 years, were recalled and had their H. pylori status determined by the 14C-urea breath test. Those found positive for H. pylori underwent endoscopic confirmation of the infection. RESULTS: Of the 94 patients restudied, with a follow-up period range of 48-96 months or a total of 549.8 yr, only two (2.2%) were again H. pylori positive. This gives an effective reinfection rate of 0.36% per patient year. In the two H. pylori-positive patients, one had normal mucosa endoscopically, whereas duodenitis without active ulceration was present in the other. The former was asymptomatic, whereas the latter patient was using ranitidine daily for symptom control. CONCLUSION: In the Australian setting, following cure of duodenal ulcer disease by eradication of H. pylori, subsequent reinfection is an unusual phenomenon. We conclude that efforts aimed at eradication of H. pylori in duodenal ulcer are justified and are worthwhile.

Use of high efficacy, lower dose triple therapy to reduce side effects of eradicating Helicobacter pylori.

OBJECTIVES: To evaluate two triple-therapy (TT) regimens of colloidal bismuth subcitrate (CBS), metronidazole, and tetracycline HCl in eradicating Helicobacter pylori, with particular attention to the frequency of resulting adverse effects of the two therapies. METHODS: A prospective, randomized controlled trial was conducted in patients with symptoms of dyspepsia who were positive for H. pylori. Subjects received a 14-day course of either 4 x/day therapy of CBS (108 mg), tetracycline HCl (500 mg), and metronidazole (250 mg), or 5 x/day therapy of CBS (108 mg), tetracycline HCl (250 mg), and metronidazole (200 mg). H. pylori status was determined endoscopically by urease test, histology, and culture. Standard questionnaires were administered to determine compliance to treatment and side effects of therapy. RESULTS: H. pylori was eradicated in 196/213 (92%) patients in the 4 x/day group and 202/210 (96%) in the 5 x/day group (p = 0.07). Side effects were significantly less frequent and less severe in the 5 x/day group (p < 0.01). CONCLUSIONS: We conclude that a lower dose, 5 x/day triple therapy treatment of H. pylori is equally efficacious to the standard 4 x/day therapy, but is accompanied by fewer and milder adverse effects.

Smoking does not contribute to duodenal ulcer relapse after Helicobacter pylori eradication.

Cigarette smoking is believed to be one of the major factors influencing duodenal ulcer (DU) recurrence. However, the influence of cigarette smoking on DU recurrence after the eradication of Helicobacter pylori has not been separately addressed. The aim of this study was to investigate DU relapse rate in smokers and nonsmokers, both with confirmed eradication of H. pylori. Patients with H. pylori eradication, demonstrated at endoscopy 4 wk post-treatment, were included in the study. Smoking history was obtained with a standard questionnaire, and patients were followed endoscopically, both yearly and at symptomatic recurrence, to detect anatomical DU recurrence. Of the 197 (121M:76F) patients enrolled in the study and followed for 1-6 yr, 80 (41%) were smokers, smoking 5-40 cigarettes/day. The 117 (59%) nonsmokers included 31 (26%) patients who had ceased smoking 4-20 yr ago. Another seven (9%) smokers ceased smoking during the follow-up period. In the 197 patients with eradicated H. pylori and cured DU, there has been no recurrence of ulcer, regardless of smoking status. We conclude that in patients with DU in whom H. pylori infection is eradicated, ulcer disease does not recur, as observed for up to 6 yr. Furthermore, cigarette smoking is not a risk factor for DU recurrence, provided H. pylori is eradicated.

Helicobacter pylori-negative gastric ulcer.

Causes of Helicobacter pylori (HP)-negative gastric ulcers (GUs) have not previously been systematically studied. In this study we examined possible causes of HP-negative GUs. Among 115 consecutive patients with endoscopic diagnoses of GU, 71 (62%) had HP infection, and 44 (38%) were found to be HP-negative. Of the 71 HP-positive patients, 47 (66%) had no other detectable causal factors, 21 (30%) were regularly taking nonsteroidal antiinflammatory drugs (NSAIDs), and three (4%) had malignant GU. Of the 44 HP-negative patients, 29 (66%) were taking NSAIDs, two (5%) had a malignant GU, whereas 13/44 (30%) (11% of total 115) patients had no identifiable cause. These patients were classified as having "idiopathic GU." Some 38/115 (33%) GUs occurred on the lesser curve, and these were more often (p = 0.012) HP-positive (76%) than prepyloric GUs (60/115 (52%)). We conclude that although most patients have an identifiable cause of GU, around 11% will have no apparent contributing factor. HP-positive GUs are more frequently located on the lesser curve. It is now important to identify the cause of GU, because this may dictate choice of management.

Oxygenating mouthguard alleviates hypoxia during gastroscopy.

A randomized study was carried out to determine the effect of oxygen (3 liters/min) via a novel oxygenating mouthguard (Oxyguard) on arterial oxygenation in 242 intravenously sedated patients undergoing gastroscopy. In another group of 21 patients, a randomized crossover study of arterial oxygen saturation using either the standard mouthguard or the oxygenating mouthguard (3 liters/min) was conducted. Significant O2 desaturation (pulse oximeter reading less than 90%) occurred in 25% of patients on room air but only 3% of those on oxygen (p less than 0.001). Severe desaturation (reading less than 85%) occurred in 5% of patients on room air but was prevented by the oxygenating mouthguard. Minimum oxygen saturation levels were significantly higher in patients on oxygen (90.5 +/- 0.3%) than on air (86.5 +/- 0.5%; p less than 0.001). In the crossover group, O2 saturation was uniformly higher in the recordings of all patients using the oxygenating mouthguard. In conclusion, administration of oxygen via the oxygenating mouthguard alleviates hypoxemia during gastroscopy and prevents severe oxygen desaturation. However, hypoxemia may occur even during use of supplemental oxygen. Hence, monitoring of arterial oxygenation is recommended.

Helicobacter pylori eradication with doxycycline-metronidazole-bismuth subcitrate triple therapy.

Triple therapy containing tetracycline HCl is currently among the most efficient combination therapies for eradication of Helicobacter pylori. Substitution of doxycycline for tetracycline HCl offers advantages of less frequent dosing and extrarenal excretion. In this study patients with duodenal ulcer or non-ulcer dyspepsia positive for H. pylori were randomized to either doxycycline or tetracycline HCl triple therapy in conjunction with bismuth subcitrate and metronidazole. Of the 34 patients taking doxycycline, only 22 (65%) achieved H. pylori eradication at the 4-week rebiopsy, compared with 36 of 39 (92%) taking tetracycline HCl (p = 0.004). We conclude that doxycycline-containing triple therapy is less effective for H. pylori eradication and offers no clinical advantage over tetracycline HCl-containing triple therapy.

Helicobacter pylori-negative duodenal ulcer.

Most patients with chronic duodenal ulcer (DU) craters have gastritis associated with Helicobacter pylori (HP), now thought to be the major cause of DU. A smaller proportion of DU patients have no detectable HP. In this study, we examined the frequency and causes of HP-negative duodenal ulcers. In 302 consecutive patients with endoscopic diagnosis of duodenal ulcer, 284 (94%) were found to have associated HP gastritis, whereas 18 (6%) were HP-negative on histology, culture, and urease test. The largest subgroup of HP-negative patients (8/18) was made up of those who had been taking nonsteroidal antiinflammatory drugs (NSAIDs), followed closely (4/18) by patients with recent intake of antibiotics. Causes of DU in the remaining subgroups included two patients with duodenal Crohn's disease, two with Gastrospirillum hominis infection, one with penetrating carcinoma of the pancreas and one with no detectable cause. We conclude that, although the most common causal factor of duodenal ulcer is HP, some 6% of DU's will be HP-negative, signaling unusual etiology. It is now important to identify the cause of duodenal ulcer so as to initiate appropriate therapy.

Cure of duodenal ulcer after eradication of Helicobacter pylori.

Eighty-two patients, whose duodenal ulcers were recurrent or resistant to H2-receptor antagonist therapy, were entered in a treatment protocol of ranitidine followed by a four-week "triple therapy" course to eradicate Helicobacter pylori (HP) infection. The triple therapy consisted of colloidal bismuth subcitrate, tetracycline and metronidazole. Duodenal ulcer healed in all 78 patients available for endoscopy and H. pylori infection was shown to be eliminated in 75 patients (96%) at rebiopsy four weeks after cessation of therapy. In these 75 remaining patients the relapse rates for H. pylori infection and duodenal ulcer were studied endoscopically, yearly and at any recurrence of symptoms. At Year 1, 71 of 73 patients remained free of H. pylori infection (HP-negative) and duodenal ulcer. The corresponding figures subsequently were: Year 2, 57/57; Year 3, 34/34; Year 4, 15/15. No duodenal ulcers recurred in HP-negative patients who were followed for up to four years. Two patients of the original cohort of 75 HP-negative patients were HP-positive with endoscopic duodenitis at 12 months, and one at 36 months, but all were without reulceration. Distorted duodenal caps gradually returned to near-normal appearance in 80% of patients by two years. From this four-year follow-up study we conclude that duodenal ulcer disease will not recur provided the patient remains free of H. pylori.

Recurrence of duodenal ulcer and Campylobacter pylori infection after eradication.

The role of Campylobacter pylori gastritis in dyspepsia could be clarified more readily if reliable eradication therapy were available. Antibiotic monotherapy and combined therapy with an antibiotic agent plus a bismuth compound have yielded poor long-term results. In this study, bismuth-tetracycline-metronidazole triple therapy has been used to eradicate C. pylori infection in 100 consecutive patients who were suffering from either a duodenal ulcer or non-ulcer dyspepsia. Examination of a follow-up endoscopic biopsy at eight weeks after treatment showed an eradication rate of C. pylori of 94%. Of 64 patients whose biopsy samples were free of C. pylori infection at eight weeks and who were available for reassessment, 60 (94%) patients had samples that remained free of C. pylori infection on examination of a repeat endoscopic biopsy at 12-37 months (mean, 19.3 months). It is concluded that "triple chemotherapy" can achieve long-term eradication of C. pylori infection effectively in the majority of treated patients and that the recurrence of duodenal ulcers thus may be diminished.