Biologics in oral medicine: ulcerative disorders.

Inflammatory ulcerative diseases of the oral mucosa are wide ranging but include especially aphthous and aphthous-like ulceration, vesiculobullous disorders and erosive lichen planus (LP). While most patients with these conditions respond to conventional topical and/or systemic immunosuppressive agents, treatment-resistant cases remain challenging. In these, the use of biologics such as tumour necrosis factor alpha (TNF-α) inhibitors or rituximab may be of benefit. This article reviews the use of biologics in ulcerative oral conditions, highlighting potential benefits, adverse effects and principles of use and future developments. TNF-α inhibitors such as infliximab can be effective in inducing resolution in oral aphthous and aphthous-like ulcers and may be an appropriate therapy in those patients in which disease is severe and refractory to, or patients are intolerant of, traditional immunomodulatory regimens. There would also seem support and rationale for use of biologics (mainly rituximab) in pemphigus but not in oral LP or other oral ulcerative conditions.

Biologics in oral medicine: Sjogren syndrome.

Oral Diseases (2012) doi:10.1111/j.1601-0825.2012.01932.x Biologic therapy has a potential to benefit patients with orofacial manifestations of Sjogren syndrome (SS). The most appropriate use of biologics would appear to be in patients with severe or multisystem features of SS, but their use early in the pathogenesis has the potential to prevent disease progression. Tumour necrosis factor-alpha blockade has not proven effective in SS. B-cell depletion using rituximab has been of benefit, mainly in relation to extraglandular features, and to some extent in relation to hyposalivation where there is still residual salivary function. Rituximab is also effective in the treatment of SS-associated (extrasalivary) lymphomas, although the therapeutic response in salivary lymphoma is poorer. Rituximab is given as a single or periodic intravenous infusion. Potential adverse effects exist, notably infusion reactions and infection, and so a full risk/benefit analysis is indicated for prospective patients. This and clinical use is best performed and monitored in conjunction with rheumatologists with appropriate training and experience in biologic therapies. Further studies of rituximab in SS are ongoing, and newer agents under trial include belimumab.

Biologics in oral medicine: oral Crohn's disease and orofacial granulomatosis.

Antitumour necrosis factor (TNF-α) therapy has a potential to benefit patients with oral lesions of Crohn's disease (CD) and patients with orofacial granulomatosis (OFG). The most appropriate use would appear to be in patients with severe or multisystem features, where other available agents have failed or have been associated with adverse effects. TNF-α antagonists (infliximab in particular) have a role in the management of orofacial CD and OFG, but potential adverse effects of TNF-α antagonists include acute infusion reactions, infection and increased risk of malignancy. Thus, a full risk-benefit analysis is indicated, with patient selection, use and subsequent monitoring coordinated with gastroenterologists with appropriate training and experience in biological therapies.

Biologics in oral medicine: principles of use and practical considerations.

Oral Diseases (2012) 18, 525-536 Biologic therapies are relatively innovative treatments aimed at modulating lymphocytes or cytokines. There are currently three broad classes of biologic therapies, tumour necrosis factor-alpha inhibitors, lymphocyte modulators and interleukin inhibitors; all are increasingly used in the treatment of inflammatory immune-mediated conditions, and several have potential applications in oral medicine. Guidelines for their use in licensed indications (e.g. rheumatoid arthritis, psoriasis, inflammatory bowel disease) include recommendations and guidance for patient selection and subsequent monitoring with discussion of potential adverse effects. An understanding of these is important when managing patients receiving biologic therapy for systemic disease, and compliance is essential in any use in oral medicine. Key aspects of current guidance are presented with particular emphasis on their relevance to clinicians working within oral and maxillofacial medicine/pathology/surgery and in specialist practice.

Efficacy of tumour necrosis factor-α antagonists in aphthous ulceration: review of published individual patient data.

BACKGROUND: Severe aphthous ulceration may require systemic immunosuppressive or immunomodulatory therapy, but a small subset of patients remains resistant to or intolerant of these agents. Although use of TNF-α antagonists in aphthous ulceration is increasingly reported, the current evidence base for use is weak and evaluation of individual cases may provide the best available data to support such use. OBJECTIVES: The aim of this study was to review all published data on the use of TNF-α antagonists in patients with severe aphthous ulceration refractory to systemic agents and discusses this in the context of any possible benefits that may guide any future use. METHODS: A comprehensive search on MEDLINE and EMBASE from 1995 to 2010 was performed using pre-defined search terms, with articles included if they met specific criteria. RESULTS: Sixteen cases from individual case reports or small case-series in which use of TNF-α antagonists in aphthous ulceration were identified in which details of previous systemic therapy and use of subsequent adjunctive therapy were available. Agents with reported success in resolving active ulceration and reducing ulcer recurrence were infliximab, etanercept and adalimumab. CONCLUSIONS: Evidence for efficacy of TNF-α antagonists in aphthous ulceration infection is limited. Such data suggest that in patients with severe aphthous ulceration TNF-α antagonists have some efficacy in inducing ulcer resolution and reducing recurrence. These agents may represent an option in severe refractory aphthosis, although in the absence of controlled studies, caution is advocated if use is to be considered.

Challenges for coring deep permafrost on Earth and Mars.

A scientific drilling expedition to the High Lake region of Nunavut, Canada, was recently completed with the goals of collecting samples and delineating gradients in salinity, gas composition, pH, pe, and microbial abundance in a 400 m thick permafrost zone and accessing the underlying pristine subpermafrost brine. With a triple-barrel wireline tool and the use of stringent quality assurance and quality control (QA/QC) protocols, 200 m of frozen, Archean, mafic volcanic rock was collected from the lower boundary that separates the permafrost layer and subpermafrost saline water. Hot water was used to remove cuttings and prevent the drill rods from freezing in place. No cryopegs were detected during penetration through the permafrost. Coring stopped at the 535 m depth, and the drill water was bailed from the hole while saline water replaced it. Within 24 hours, the borehole iced closed at 125 m depth due to vapor condensation from atmospheric moisture and, initially, warm water leaking through the casing, which blocked further access. Preliminary data suggest that the recovered cores contain viable anaerobic microorganisms that are not contaminants even though isotopic analyses of the saline borehole water suggests that it is a residue of the drilling brine used to remove the ice from the upper, older portion of the borehole. Any proposed coring mission to Mars that seeks to access subpermafrost brine will not only require borehole stability but also a means by which to generate substantial heating along the borehole string to prevent closure of the borehole from condensation of water vapor generated by drilling.

Apolipoprotein E and methylenetetrahydrofolate reductase genetic polymorphisms in relation to other risk factors for cardiovascular disease in UK Caucasians and Black South Africans.

Genetic polymorphisms for apolipoprotein E (apo E) and methylenetetrahydrofolate reductase (MTHFR) are believed to modulate risk of coronary heart disease (CHD) acting through regulation of lipid and homocysteine metabolism, respectively. The distributions of apo E and MTHFR alleles in Black South Africans, a population with a low CHD incidence, and UK Caucasians from the Cambridge area, with a higher CHD incidence, were therefore compared. Clinically healthy volunteers (207), including 107 UK Caucasians from the Cambridge area and 100 Black South Africans, participated in the study. Apo E and MTHFR genotypes were determined in all of them. Analyses for serum total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides and plasma fibrinogen were carried out in 65 UK Caucasians and 60 Black South Africans. The apo E epsilon4 allele, which is associated with elevated CHD risk, was present in 48% of Black South Africans compared to 20.8% of Caucasians (P < 0.0001); however, both total and LDL cholesterol levels in Black South Africans were 18-32% lower than in Caucasians with similar apo E genotypes. Hyperhomocysteinemia-causing MTHFR 677T variant was detected in only 20% of Black South Africans (no homozygotes) versus 56% of Caucasians with 12% homozygotes (P<0.0001). Our findings suggest that the potentially unfavourable pattern of apo E allele distribution in Black South Africans does not result in increased CHD incidence due to protection by dietary and/or other life style related factors. The exceptionally low frequency of MTHFR mutant homozygotes in this population suggests that this polymorphism should not be regarded as an important CHD risk factor among Black South Africans.

Quantitation of DNA from exfoliated colonocytes isolated from human stool surface as a novel noninvasive screening test for colorectal cancer.

The only widely used screening test for early detection of colorectal cancer, the fecal occult blood test, lacks both sensitivity and specificity because it relies upon incidental bleeding rather than the neoplastic process. With the purpose of developing a new noninvasive diagnostic approach, we quantified DNA extracted from cells isolated from the surface of human stools by a novel procedure. Stools collected from 28 healthy individuals, 17 colorectal cancer patients, and 11 colorectal polyp patients were analyzed. A stool DNA index (SDNAI), expressed as DNA amount in nanograms per gram of stool, had a remarkable 4.5-fold difference in mean values between colorectal cancer patients and healthy people of comparable age. SDNAI was 2133 +/- 407 in the cancer group versus 469 +/- 65 in healthy people of the older (> 50 years) age group (P = 0.0005). The difference was independent of tumor location and size. If 700 ng of DNA/g of stool was taken as a cutoff SDNAI value in discrimination between older healthy people and cancer patients, sensitivity and specificity values reached 1.00 and 0.81, respectively. Age dependence of SDNAI was demonstrated by substantially lower SDNAI values (mean, 227 +/- 41) in younger healthy individuals. Polyp patients sometimes displayed elevated SDNAI values, but considerable variation was observed (mean, 1215 +/- 548). These preliminary findings indicate that SDNAI provides a novel, simple, and powerful noninvasive test for colorectal cancer early detection and screening. The fundamental advantage of the SDNAI is that it directly characterizes colonic epithelium involved in carcinogenesis.

Odontogenic myxoma in an adolescent with tuberous sclerosis.

Tuberous sclerosis is a hamartoneoplastic syndrome characterised by early onset of convulsive seizures with mental retardation. Oral abnormalities, including enamel hypoplasia and mucosal fibromas, have been previously reported. We report here a 17-year-old girl with this disorder who had received repeated dental trauma. She presented with a swelling associated with a traumatised maxillary central incisor that suggested a diagnosis other than the odontogenic myxoma found at operation. Odontogenic myxoma has not previously been reported in this condition; it may represent an unusual phenotypic expression of the genetic defect understood to determine tuberous sclerosis, or it may be an unrelated coincidental finding.

Comparison of metabolic effects of vegetables and teas with colorectal proliferation and with tumour development in DMH-treated F344 rats.

The aim of this study was to screen potentially chemopreventive vegetables and teas for their effects as human dietary components for the colorectal epithelium and also to seek biomarkers of preventive efficacy. Groups of F344 rats were adapted to a human basal diet supplemented with vegetables or teas, having known contents of glucosinolates, polyphenols and anti-oxidants. Both inductions and suppressions were found for overall glutathione S-transferase (GST) and quinone reductase activities. The mitotic index (MI) showed a three-fold range between groups, with substantial reductions by black tea, spinach, petit pois and peppers. Changes to PCNA labelling index and proliferation zone were marginal. No correlation was found between colonic and hepatic enzyme activities, nor with glucosinolate intake. Colonic MI was associated with the activity ratio GST(hepatic)/GST(colonic) (r = 0.49, P < 0.002), possibly reflecting a need for direct induction rather than exposure to products of hepatic conjugation.

Effect of meat and resistant starch on fecal excretion of apparent N-nitroso compounds and ammonia from the human large bowel.

N-nitroso compounds are produced in the human large intestine, but little is known about the dietary modulation of their synthesis at this site. The effects of meat and resistant starch on the fecal excretion of N-nitroso compounds, measured as apparent total N-nitroso compounds (ATNC), were therefore investigated in a crossover study involving eight healthy men. Three controlled diets that differed in the amount of meat (40 or 600 g) and resistant starch (37 g added to 600 g meat diet) were fed in random order, and fecal ATNC, as well as fecal ammonia and parameters of bowel function, were measured after 19 days of dietary adaptation. Mean ATNC excretion during the high-meat period was 114 micrograms/day, three times that during the low-meat period of 35 micrograms/day (p = 0.02); ammonia excretion was twice that during the low-meat period: 2.9 vs. 1.4 mmol/day (p = 0.03). The fecal ATNC were dissolved in the fecal water, and 45% had a molecular weight < 3,000. The addition of readily fermentable resistant starch to the high-meat diet significantly increased stool output from 118 to 153 g/day and decreased fecal pH from 7.2 to 6.6 but had no significant effect on fecal ATNC (151 micrograms/day), ammonia (3.7 mmol/day), whole gut transit time, urinary nitrate, or plasma urea. ATNC produced in the large bowel in association with a high-meat intake could represent an important source of DNA-damaging alkylating agents in the human large bowel.

Does increased endogenous formation of N-nitroso compounds in the human colon explain the association between red meat and colon cancer?

High red meat diets have been linked with risk of sporadic colorectal cancer; but their effects on mutations which occur in this cancer are unknown. G-->A transitions in K-ras occur in colorectal cancer and are characteristic of the effects of alkylating agents such as N-nitroso compounds (NOC). We studied th effect of red meat consumption on faecal NOC levels in eight male volunteers who consumed diets low or high in meat (60 or 600 g/day), as beef, lamb or pork, whilst living in a metabolic suite. Increased intake of red meat induced a significant (P<0.024) 3-fold increase from 40 + or - 7 to ab average of 113 + or - 25 microgram/day NOC, a range of exposure in faeces similar to that from tobacco-specific NOC in cigarette smoke. THe diets were isoenergetic and contained equal amounts of fat, but concentrations of heterocyclic amines were low. Faecal excretion of the promotor ammonia was significantly increased to 6.5 + or - 1.08 mmol/day. When the high red meat diets were supplemented with 20 g phytate-free wheat bran in six volunteers there was no reduction in NOC levels (mean 138 + or - 41 microgram/day NOC), but faecal weight increased. Higher starch and non-starch polysaccharide intakes reduced intraluminal cross-linking in microcapsules (r=-0.77) and reduced faecal pH (r=-0.64). In two volunteers there was no effect of 600 g white meat and fish o faecal NOC (mean low white meat diet 68 + or - 10 microgram/day, high white meat 56 + or -6 microgram/day nor on faecal nitrate, nitrite and iron. Faecal nitrite levels increased on changing from a white to red meat diet (mean high white meat diet 46 + or - 7 mg/day, high red meat diet mean 80 + or - 7 mg/day.) Increased endogenous production of NOC and precursors from increased red meat, but not white meat and fish, consumption may be relevant to the aetiology of colorectal cancer.

Use of radionuclide imaging to determine gastric emptying of carbohydrate solutions during exercise.

OBJECTIVE: To investigate the repeatability of continual assessment of the gastric emptying rates of carbohydrate solutions in exercising subjects using 99mtechnetium labelling. METHODS: Gastric emptying of a 5% glucose solution and an iso-osmotic maltodextrin solution was measured using 3 MBq of 99mtechnetium labelled diethylene triamine penta-acetic acid (DTPA) and continuous gamma camera imaging in five male subjects. The subjects performed four 1 h trials at 70% VO2 peak on a cycle ergometer. After 15 min, 200 ml of a radiolabelled solution of glucose or maltodextrin were ingested in a blind crossover protocol. The two solutions were each ingested on separate occasions (trial 1 and trial 2) to establish repeatability. RESULTS: Statistical analysis showed no differences between trial 1 and trial 2 for both solutions. There were no significant differences for the emptying rates between the two test solutions. CONCLUSIONS: Posterior imaging using a computer linked gamma camera following the ingestion of 99mtechnetium labelled DTPA mixed with carbohydrate solutions provides a repeatable method of assessing gastric emptying characteristics in exercising subjects. This technique showed no significant differences between the emptying rates of a single dose of iso-osmotic glucose or maltodextrin solution.

Regulation of chick muscle satellite cells by fibroblast growth factors: interaction with insulin-like growth factor-I and heparin.

This study describes the effect of acidic and basic fibroblast growth factor (FGF) on DNA synthesis in chick satellite cells in vitro and interactions with insulin-like growth factor-I (IGF-I) and exogenous heparin. Basic bFGF stimulated incorporation of [3H]thymidine into DNA with a half-maximum concentration (ED50) of 3.23 +/- 0.33 pmol/l, more than 500-fold more potent than acidic FGF (ED50 = 2.13 +/- 0.5 nmol/l). Both bFGF and IGF-I allowed the cells to traverse the cell cycle with an approximate length of the G1 phase of 12 h. When cells were incubated with bFGF and IGF-I together their effects on DNA synthesis were additive rather than synergistic throughout the full concentration range. Incubation of satellite cells with low concentrations of heparin (ng/ml) to mimic the effect of endogenous heparan sulphate proteoglycan caused a small increase in DNA synthesis, whereas higher concentrations (microgram/ml) inhibited DNA synthesis in a dose-related manner. A low concentration of heparin increased DNA synthesis at the highest concentration of bFGF, but high doses of heparin inhibited the response to bFGF throughout the dose-response curve but without altering the ED50. RNAse protection assay showed the expression of bFGF mRNA in proliferating cells which appeared to decrease on differentiation. The results suggest that aspects of neonatal muscle development are regulated by interactions between autocrine/paracrine growth factors such as IGF-I and bFGF, perhaps IGF-I derived from the circulation, and components of the extracellular matrix. Concentrations of the matrix components may change throughout the neonatal period and into adulthood and have an important effect on the regulatory role played by the growth factors.

Microencapsulation of DNA within alginate microspheres and crosslinked chitosan membranes for in vivo application.

Calf thymus DNA was microencapsulated within crosslinked chitosan membranes, or immobilized within chitosan-coated alginate microspheres. Microcapsules were prepared by interfacial polymerization of chitosan, and alginate microspheres formed by emulsification/internal gelation. Diameters ranged from 20 to 500 microns, depending on the formulation conditions. Encapsulated DNA was quantified in situ by direct spectrophotometry (260 nm) and ethidium bromide fluorimetry, and compared to DNA measurements on the fractions following disruption and dissolution of the microspheres. Approximately 84% of the DNA was released upon core dissolution and membrane disruption, with 12% membrane bound. The yield of encapsulation was 96%. Leakage of DNA from intact microspheres/capsules was not observed. DNA microcapsules and microspheres were recovered intact from rat feces following gavage and gastrointestinal transit. Higher recoveries (60%) and reduced shrinkage during transit were obtained with the alginate microspheres. DNA was recovered and purified from the microcapsules and microspheres by chromatography and differential precipitation with ethanol. This is the first report of microcapsules or microspheres containing biologically active material (DNA) being passed through the gastrointestinal tract, with the potential for substantial recovery.

Gastrointestinal monitoring of DNA-damaging agents with magnetic microcapsules.

Semi-permeable, magnetically recoverable, reactive microcapsules of several types were developed for gastrointestinal (GI) monitoring of several kinds of DNA-damaging agents in relation to (i) systematic dietary variations designed to discriminate the GI effects of food components known to modulate colorectal cancer risk, and (ii) then thereby to achieve the identification of a range of endogenous agents and their dietary sources. These microcapsules contained as targets either amino functions (for alkylating agents), 14CH3 functions (to detect cross-linking agents and reactive oxygen species precursors), or a copper porphyrin (for carcinogens having planar molecular structure). Other microcapsules had a cleavable target based on guanine, which is shown to trap endogenous agents and a [14C]BaP metabolites in male F344 rats consuming a putative high-risk diet (high fat, high meat, low fibre non-starch polysaccharide (NSP)), but not significantly when consuming the contrasting low-risk diet. Detailed investigations of the action of fibre NSP and fat showed that increased intake from low to high levels of the British diet range enhanced or decreased several carcinogenesis-relevant end-points more than two-fold. Detection of these disproportionately large effects on microcapsule trapping, hepatic DNA adducts from endogenous agents, colorectal mucosal cell mitoses/micronuclei, endogenous cross-linking agents, and gut microfloral enzyme activities (a) are consistent with epidemiological data on the importance of these components and (b) provide the basis for establishing with microcapsules some potential dietary preventive measures in volunteers.

Reactive microcapsules for detection of carcinogen sources in the gut.

Entrapment within the gastrointestinal tract of reactive carcinogens and DNA-damaging agents was achieved by use of novel magnetically-retrievable semi-permeable microcapsules. Investigation of colorectal cancer aetiology cannot be based on faecally-excreted agents, and this in situ trapping provides the only means for monitoring internal exposures. These microcapsules were initially prepared from polyethyleneimine with a polyamide membrane so as to resist microfloral and enzymatic damage, and are shown to entrap metabolites of radioactive carcinogens with substantial influences of human dietary components that were consistent with previous epidemiological results on diet-related cancer risks for the human colon. These microcapsules were subsequently modified by covalent attachment of target moieties, and used to reveal several types of endogenous agent of carcinogenic significance. These included crosslinking and nitrosating agents, precursors of reactive oxygen species, and carcinogens having planar molecular structure. Preliminary studies in man have been undertaken and have showed diet-dependent effects. The aim of this work is to identify DNA-damaging agents and their dietary sources, and preliminary work with modified microcapsules and in volunteers consuming controlled diets indicates this to be feasible. Such microcapsules could in principle be used for many other types of applications beyond the scope of this present work.