The Salivary Mycobiome Contains 2 Ecologically Distinct Mycotypes.

A broad range of fungi has been detected in molecular surveys of the oral mycobiome. However, knowledge is still lacking on interindividual variability of these communities and the ecologic and clinical significance of oral fungal commensals. In this cross-sectional study, we use internal transcribed spacer 1 amplicon sequencing to evaluate the salivary mycobiome in 59 subjects, 36 of whom were scheduled to receive cancer chemotherapy. Analysis of the broad population structure of fungal communities in the whole cohort identified 2 well-demarcated genus-level community types (mycotypes), with Candida and Malassezia as the main taxa driving cluster partitioning. The Candida mycotype had lower diversity than the Malassezia mycotype and was positively correlated with cancer and steroid use in these subjects, smoking, caries, utilizing a removable prosthesis, and plaque index. Mycotypes were also associated with metabolically distinct bacteria indicative of divergent oral environments, with aciduric species enriched in the Candida mycotype and inflammophilic bacteria increased in the Malassezia mycotype. Similar to their fungal counterparts, coexisting bacterial communities associated with the Candida mycotype showed lower diversity than those associated with the Malassezia mycotype, suggesting that common environmental pressures affected bacteria and fungi. Mycotypes were also seen in an independent cohort of 24 subjects, in which cultivation revealed Malassezia as viable oral mycobiome members, although the low-abundance Malassezia sympodialis was the only Malassezia species recovered. There was a high degree of concordance between the molecular detection and cultivability of Candida, while cultivation showed low sensitivity for detection of the Malassezia mycotype. Overall, our work provides insights into the oral mycobiome landscape, revealing 2 community classes with apparently distinct ecologic constraints and specific associations with coexisting bacteria and clinical parameters. The utility of mycotypes as biomarkers for oral diseases warrants further study.

The Porphyromonas gingivalis O antigen is required for inhibition of apoptosis in gingival epithelial cells following bacterial infection.

BACKGROUND AND OBJECTIVE: Porphyromonas gingivalis infection induces apoptosis inhibition in gingival epithelial cells; however, it is not fully understood which bacterial effectors are involved in this process. The aim of this study is to evaluate whether the P. gingivalis lipopolysaccharide (LPS), specifically the O-antigen region, affects adherence, invasion, viability and apoptosis of gingival epithelial cells. MATERIAL AND METHODS: Gingival epithelial cells (OKF6/TERT2 line) were infected by different freshly prepared P. gingivalis clinical isolates, obtained from subjects with chronic periodontitis (CP3 and CP4) and healthy individuals (H1 and H3). Periodontitis and healthy isolates show differences in O-antigen production, as healthy isolates lack the O-antigen region. In addition, cells were infected by a site-specific mutant lacking the O-antigen portion. After 24 h postinfection, cell proliferation, viability and apoptosis were evaluated by Trypan blue, MTS and annexin V assays, respectively. Bacterial invasion, adhesion and proliferation were measured by gentamicin/metronidazole protection assays. Finally, toll-like receptor (TLR)2 and TLR4 mRNA expression was evaluated by quantitative reverse transcription-polymerase chain reaction. Statistical analysis was performed using ANOVA, Tukey's or Dunnett's tests (p < 0.05). RESULTS: At 24 h postinfection, strains lacking the O-antigen region (healthy isolates and O-antigen ligase-deficient strain) were unable to increase proliferation and viability, or decrease apoptosis as compared with strains producing intact LPS (periodontitis isolates and reference strain). However, the presence of the O-antigen neither contributed to changes in the ability of the bacteria to adhere to or invade cells, nor to intracellular survival. The presence of O-antigen also increased the expression of TLR4 (nearly sixfold), which correlated with inhibition of apoptosis. CONCLUSION: The O-antigen region of P. gingivalis LPS is required to increase gingival epithelial cell viability upon infection by bacteria and this increase is attributable to a reduction in apoptosis. Moreover, although bacterial internalization is required, the effects observed are not due to alterations in P. gingivalis adherence, invasion or intracellular survival. Interestingly, inhibition of apoptosis correlates with increased TLR4 expression, suggesting a role for TLR4 in this process.

Improved maintenance of remission in ulcerative colitis by balsalazide 4 g/day compared with 2 g/day.

The efficacy of two doses of balsalazide for the maintenance of remission in patients with ulcerative colitis was compared in a double-blind multicentre trial. Sixty-five patients received a 2 g daily dose, and 68 a 4 g dose. The patient groups were similar at entry for sex, age, and disease distribution. Clinical assessment was carried out at 3-monthly intervals, with sigmoidoscopy, rectal biopsy, and blood tests on entry and at 26 and 52 weeks. Clinical relapse over twelve months was significantly less common on the 4 g dose (36%), than on the 2 g dose (55%), P less than 0.01. There were eight withdrawals on 2 g daily and 13 on 4 g daily, six and nine respectively being mainly due to gastrointestinal intolerance. It is concluded that balsalazide is a well-tolerated drug, and is effective for the maintenance of remission in patients with ulcerative colitis, the optimal dose being greater than 2 g daily.

Does ulcerative colitis behave differently in the elderly?

The clinical course of all new patients with ulcerative colitis or indeterminate colitis aged 65 years or older diagnosed in one health district (population 274,000) between 1 January 1975 and 31 December 1984 has been compared with that of all new patients 55 years or younger diagnosed in the same period. Elderly patients were admitted more often in a first attack and were more likely to receive systemic steroids. No elderly patient required urgent surgery and no patient in either group died of ulcerative colitis or its complications. The mortality amongst elderly patients with ulcerative colitis was no greater than expected in a population of the same age. The prognosis for ulcerative colitis in elderly patients is the same as for younger patients.

Surveillance in ulcerative colitis: burdens and benefit.

A review of all patients with ulcerative colitis in one health district between 1975-84 revealed an incidence and prevalence of 7.1 and 84/100,000 population respectively. One hundred and ninety five new patients were diagnosed and 313 patients seen and followed up in the clinic for 1168 patient years. None of these patients died from colitis or a complication. On routine colonoscopy three cases had high grade dysplasia and two asymptomatic carcinomas (Duke's stage A and B). Eighty four patients were known to have ulcerative colitis, but were lost to follow up from the hospital clinic; the total time they were not under hospital surveillance was 315 patient years. At the end of the study these patients were contacted or clinical details obtained from their general practitioners. Five of these patients subsequently presented with symptomatic carcinomas (two Duke's B, one Duke's C and two with metastases); three of these five patients have died from their tumours. Of 48 patients thought to have only mild colitis on initial investigation 21 (43%) had substantial colitis (and two carcinomas) on colonoscopy after eight years of disease. Therefore, patients with apparently distal colitis should be followed in the clinic as well as those with known extensive colitis. For a surveillance programme in a district general hospital, eight patients per 100,000 population need to be seen weekly, 12 colonoscopies/100,000 population need to be carried out annually and the cost for each carcinoma detected is approximately 6015 pounds.

Acute colitis in a district general hospital.

A review of all patients who had been admitted to hospital with acute ulcerative colitis in one health district between 1975 and 1984 showed that 96 had required 114 admissions with acute colitis: 42% (40) were admitted during their first attack, and 20% (19) required urgent surgery. A further nine patients underwent surgery after responding initially to intensive medical treatment that did not check the attack. There were no deaths from acute colitis. Thirteen patients underwent elective surgery for ulcerative colitis, and there were no deaths. The prognosis for acute colitis in district general hospitals has improved.

A prospective randomized study of effect of proximal gastric vagotomy and vagotomy and antrectomy on bile reflux, endoscopic mucosal abnormalities and gastritis.

71 patients participated in a double-blind trial which compared proximal gastric vagotomy (PVG) with vagotomy and antrectomy (V & A). 82 percent of the patients subsequently volunteered for endoscopy 6 to 12 months after operation and 65 percent for measurement of fasting bile reflux (FBR) and peak acid output (PAO). The results of these follow-up assessments are given in this paper. None of the 36 patients who had undergone V & A had a recurrent ulcer; in contrast ulcers or fresh scars were found in 5 of 35 patients after PGV, even in 2 who had no symptoms. Erythema of the gastric mucosa was seen more commonly after V & A than PGV. Such erythema was associated with high levels of fasting bile reflux (an objective measure of reflux of bile into the stomach) and with symptoms of bile vomiting and mild epigastric pain. High levels of fasting bile reflux were not found after PGV. Histological gastritis of the proximal stomach was equally common after both operations in patients without a recurrent ulcer. Gastritis was not related to endoscopic mucosal erythema or fasting bile reflux, but did correlate with peak acid output. These results confirm that bile reflux is associated with mucosal erythema and symptoms after V & A but that significant bile reflux does not occur after PGV. However, bile reflux is not related to gastritis, which appears to be the result of an operation (either PGV or V & A) which successfully reduces peak acid output.

Gastrointestinal bleeding. Endoscopic diagnosis.

Emergency endoscopy is the most accurate method of diagnosis in acute upper gastrointestinal haemorrhage. As yet this increased diagnostic accuracy has not been shown to affect the final outcome and a double-contrast barium meal is almost as accurate in the diagnosis of chronic lesions. Nevertheless, the decision to operate on a bleeding patient is difficult to make without a diagnosis and this is most accurately made initially by endoscopy followed by angiography or a barium meal when necessary.

A study of the aetiology of gastritis following gastric surgery. I. Immunofluorescent studies of the gastric mucosa.

The gastritis which follows surgical trauma is probably not of autoimmune origin. Although identical with the gastritis of pernicious anaemia (PA) upon routine histological examination, immunofluorescent examination of post-operative gastritis differs in that IgA-containing plasma cells alone are found, in contrast to the predominantly IgG-containing plasma cells in PA.

A study of the aetiology of gastritis following gastric surgery. II. Studies of cell-mediated immunity.

Crude gastric antigen is shown to cause leucocyte migration inhibition in five out of ten patients with pernicious anaemia. We did not find any migration inhibition using leucocytes from twenty patients with severe post-operative gastritis, including fifteen with atrophic gastritis.

Comparison of brush cytology before or after biopsy for diagnosis of gastric carcinoma.

A randomized trial has compared the results of brush cytology before or after biopsy in patients with solitary gastric lesions. One hundred and eleven carcinomas were identified in 324 patients. False positive histological reports were recorded in 2 patients but there were no false positive cytology results. The cumulative accuracy of biopsy and cytology in patients with carcinoma was 97 per cent, which was significantly better than biopsy alone (83 per cent, P less than 0.001) or cytology alone (87 per cent, P less than 0.001). The cumulative results of brushing before biopsy were significantly better than results obtained by brushing after biopsy (P less than 0.05) and indicate that brush cytology should normally be performed before biopsy.

Cimetidine effects on prolactin release and production.

The effect of cimetidine 1600 mg. daily for three months on prolactin and related hormones is reported. Basal prolactin levels rose slightly but not significantly. There was no change in basal thyroid and sex hormone levels nor in the prolactin, gonadotrophin or thyrotrophin responses to releasing hormone stimulation. Since intravenous cimetidine induces a transient hyperprolactinemia it appears that cimetidine may facilitate release of prolactin but has no effect on its synthesis.

Selection of patients for bile diversion surgery: use of bile acid measurement in fasting gastric aspirates.

Eighteen patients with dyspepsia and vomiting which followed surgery for peptic ulcer have completed a study to examine the role of diverting bile from the stomach by a Roux-en-Y procedure. Bile regurgitation and mild epigastric pain relieved by vomiting were abolished. Measurements of bile acids in the fasting gastric aspirate were useful in predicting the outcome of surgery; good results were obtained when initially there was reflex into the stomach of more than 120 mumol/hour of bile acids. A wider group of patients than those selected in previous series may benefit from this operation, as good results can be obtained in patients with dyspepsia relieved by alkali and without achlorhydria or gastritis. Endoscopy was repeated one year after Roux-en-Y operation. Erythema of the mucosa was improved, but gastritis did not improve.

Measurement of bile acids in fasting gastric aspirates: an objective test for bile reflux after gastric surgery.

We measured the concentration of bile acids in gastric aspirates from patients who had had operations for peptic ulcer. Some patients were asymptomatic and some had postoperative symptoms of the type that have been attributed to duodenogastric reflux. Samples were obtained via a nasogastric tube when the patients were fasting, after food, after pentagastrin, and overnight. We related the concentration and amount of bile acid and the volume aspirated to the presence or absence of symptoms and compared the results with radiological and endoscopic assessments of duodenogastric reflux. The most useful index to discriminate between symptomatic and asymptomatic patients was the amount of bile reflux in half an hour's aspiration from the fasting stomach; this we have termed 'fasting bile reflux' (FBR) and expressed as mumol bile acids refluxing/hour. A figure greater than 120 mumol/h was present in 17 of 22 symptomatic patients and in all who complained of bile regurgitation or bile vomiting. The FBR was less than 120 mumol/h in all of 20 asymptomatic patients, although some of them had reflux detected radiologically and endoscopically.

Hydrotalcite in the treatment of bile vomiting.

Seventeen patients have completed a double-blind cross-over study of hydrotalcite against placebo in the treatment of bile vomiting after surgery for peptic ulcer. Overall there was no significant difference between the two treatments, with 9 patients improving on hydrotalcite and 5 on placebo. The original operation had been peformed less than 3 years before the study in 9 patients; in this subgroup there was an improvement on hydrotalcite treatment in 8 patients but in only 1 on placebo. These differences are statistically significant (P less than 0.005). Nausea, vomiting, heartburn and epigastric tenderness were improved although gastritis and endoscopic changes were not affected. It appears that hydrotalcite can help palliate symptoms of bile vomiting occuring soon after surgery for peptic ulcer.

Symptomatic significance of gastric mucosal changes after surgery for peptic ulcer.

Eighty-four patients who had undergone different types of operation for duodenal ulcer have been studied by endoscopy and gastric biopsy. Half suffered from dyspepsia and vomiting but the other half had no symptoms and acted as controls. Endoscopic and histological abnormalities were found in both groups of patients. However, certain findings occurred more commonly in those with symptoms; severe and extensive hyperaemia, bile staining of the gastric mucus, and bile reflux seen on endoscopy were all significantly more common in those with symptoms than in those without. Active gastritis in the proximal stomach was also more common in those with symptoms. Gastritis of the stoma and antrum was found in 89% of all patients; as it was unconnected with symptoms it can be regarded as a "normal" finding. The incidences of contact bleeding, erosions, and oedema were not significantly different in the two groups.

A symptomatic discriminant to identify recurrent ulcer in patients with dysperpsia after gastric surgery.

A questionnaire has been completed by 99 patients referred for investigation of symptoms after gastric operations. The replies were analysed in an attempt to distinguish patients with a recurrent peptic ulcer from those with no recurrent ulcer. All cases were investigated by barium meal, endoscopy, and oral cholecystography. All recurrent ulcers were confirmed by reoperation and patients with gastric carcinoma, gallstones, or symptomatic hiatus hernia were excluded. The study was retrospective in 40 patients in whom the diagnosis was already confirmed when the questionnaire was analysed and prospective in 59 in whom the diagnosis was originally unknown. The replies were analysed with (a) a small computer using Bayes' theorem, (b) weighted tables, and (c) a discriminant analysis. The computer prediction of the prospective data was 85% accurate. The results of simpler methods were almost as good as the computer prediction, and questions related only to the severity of pain and vomiting accurately distinguished recurrent ulcer from other causes of dyspepsia in 81% of patients.