Downregulation of CCL22 and mutated NOTCH1 in tongue and mouth floor squamous cell carcinoma results in decreased Th2 cell recruitment and expression, predicting poor clinical outcome.

OBJECTIVE: Tongue and mouth floor squamous cell carcinoma (T/MF SCC) exhibits a high rate of local recurrence and cervical lymph node metastasis. The effect of the tumor microenvironment on T/MF SCC remains unclear. MATERIALS AND METHODS: Transcriptome and somatic mutation data of patients with T/MF SCC were obtained from HNSC projects of the Cancer Genome Atlas. Immune infiltration quantification in early- (clinical stage I-II) and advanced-stage (clinical stage III-IV) T/MF SCC was performed using single sample Gene Set Enrichment Analysis and MCPcounter. Differentially expressed gene data were filtered, and their function was assessed through Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses. Kaplan-Meier survival curve analysis and Cox regression model were conducted to evaluate the survival of patients with the CCL22 signature. Maftools was used to present the overview of somatic mutations. RESULTS: In T/MF SCC, T helper (Th)2 cell counts were significantly increased in patients with early-stage disease compared to those with advanced-stage disease. Expression of the Th2 cell-related chemokine, CCL22, was downregulated in patients with advanced-stage T/MF SCC. Univariate and multivariate Cox analyses revealed that CCL22 was a good prognostic factor in T/MF SCC. A nomogram based on the expression of CCL22 was constructed to serve as a prognostic indicator for T/MF SCC. NOTCH1 mutations were found at a higher rate in patients with advanced-stage T/MF SCC than in those with early-stage T/MF SCC, resulting in the inhibition of the activation of the NOTCH1-Th2 cell differentiation pathway. The expression levels of CCL22, GATA-3, and IL4 were higher in patients with early-stage T/MF SCC than in those with advanced-stage T/MF SCC. CONCLUSION: In T/MF SCC, high expression of CCL22 may promote the recruitment of Th2 cells and help predict a better survival. Mutations in NOTCH1 inhibit the differentiation of Th2 cells, facilitating tumor progression through a decrease in Th2 cell recruitment and differentiation.

Noninvasive sublingual microvascular imaging reveals sex-specific reduction in glycocalyx barrier properties in patients with coronary artery disease.

BACKGROUND: Risk factors for coronary artery disease (CAD) have been associated with endothelial dysfunction and degradation of the endothelial glycocalyx. This study was designed to compare sublingual microvascular perfusion and glycocalyx barrier properties in CAD patients and controls using noninvasive side stream darkfield imaging. METHODS: Imaging of the sublingual microvasculature was performed in 52 case subjects (CAD confirmed by left heart catheterization) and 63 controls (low Framingham risk score). Red blood cell (RBC) filling percentage and functional microvascular density, measures of microvascular perfusion, and perfused boundary region (PBR), an index of glycocalyx barrier function, were measured in microvessels with a diameter ranging from 5-25 µm. RESULTS: RBC filling percentage was lower in patients with CAD compared to controls (p < .001). Functional microvascular density did not differ between groups. The overall PBR was marginally greater in the CAD group compared to the control group (p = .08). PBR did not differ between male CAD cases and controls (p = .17). However, PBR was greater in females with CAD compared with female controls (p = .04), indicating reduced glycocalyx barrier function. This difference became more pronounced after adjusting for potential confounders. CONCLUSIONS: Our data suggest that patients with CAD are characterized by a reduction in percentage of time microvessels are occupied by RBCs. In addition, CAD is significantly associated with impaired sublingual microvascular glycocalyx barrier function in women but not men. More research is needed to determine the significance of peripheral microvascular dysfunction in the pathophysiology of CAD, and how this may differ by sex.

Sublingual endothelial glycocalyx and atherosclerosis. A cross-sectional study.

BACKGROUND: Damage to endothelial glycocalyx is thought to be an early marker of atherosclerosis and measuring reduced glycocalyx size clinically via the Perfused Boundary Region (PBR) may allow early detection of cardiovascular disease. However, the true value of the glycocalyx in estimating cardiovascular risk or detecting cardiovascular disease is uncertain. We therefore investigated whether small glycocalyx size is associated with cardiovascular risk or disease in a large multi-ethnic cohort. METHODS: In a multi-ethnic community-based sample (N = 6169, 42.4% male, mean age 43.6 ±13) we applied multiple imputation for missing data and used logistic regression and odds ratios to cross-sectionally investigate the relationship of small glycocalyx size as estimated by highest quartile of PBR with, on the one hand, classical risk factors for atherosclerosis including age, sex, diastolic and systolic blood pressure, LDL, HDL, triglycerides, BMI, diabetes, smoking status, and antihypertensive and lipid-lowering medication; on the other hand, prevalent cardiovascular disease. Analyses were additionally adjusted for ethnicity. RESULTS: With PBR divided in quartiles, the highest PBR quartile (smallest glycocalyx size) as dependent variable was independently associated with female sex (OR for male versus female: 0.61, 95% CI: 0.53, 0.70) and diabetes (OR: 1.28, 95% CI: 1.03-1.59) in a model adjusted for all classical risk factors of atherosclerosis and for ethnicity. With regard to cardiovascular disease, no association was found between the smallest glycocalyx size as independent variable and overall cardiovascular disease, coronary heart disease and revascularization procedures, or stroke. CONCLUSIONS: Small glycocalyx size as estimated by highest PBR is associated with female sex and diabetes, which do not completely reflect a high cardiovascular risk profile. At the same time, glycocalyx size is not associated with prevalent cardiovascular disease.

Intestinal and sublingual microcirculation are more severely compromised in hemodilution than in hemorrhage.

The alterations in O2 extraction in hemodilution have been linked to fast red blood cell (RBC) velocity, which might affect the complete release of O2 from Hb. Fast RBC velocity might also explain the normal mucosal-arterial Pco2 (ΔPco2). Yet sublingual and intestinal microcirculation have not been completely characterized in extreme hemodilution. Our hypothesis was that the unchanged ΔPco2 in hemodilution depends on the preservation of villi microcirculation. For this purpose, pentobarbital-anesthetized and mechanically ventilated sheep were submitted to stepwise hemodilution (n = 8), hemorrhage (n = 8), or no intervention (sham, n = 8). In both hypoxic groups, equivalent reductions in O2 consumption (V̇o2) were targeted. Microcirculation was assessed by videomicroscopy, intestinal ΔPco2 by air tonometry, and V̇o2 by expired gases analysis. Although cardiac output and superior mesenteric flow increased in hemodilution, from the very first step (Hb = 5.0 g/dl), villi functional vascular density and RBC velocity decreased (21.7 ± 0.9 vs. 15.9 ± 1.0 mm/mm(2) and 1,033 ± 75 vs. 850 ± 79 µm/s, P < 0.01). In the last stage (Hb = 1.2 g/dl), these variables were lower in hemodiution than in hemorrhage (11.1 ± 0.5 vs. 15.4 ± 0.9 mm/mm(2) and 544 ± 26 vs. 686 ± 70 µm/s, P < 0.01), and were associated with lower intestinal fractional O2 extraction (0.61 ± 0.04 vs. 0.79 ± 0.02, P < 0.01) but preserved ΔPco2 (5 ± 2 vs. 25 ± 4 mmHg, P < 0.01). Therefore, alterations in O2 extraction in hemodilution seemed related to microvascular shunting, not to fast RBC velocity. The severe microvascular abnormalities suggest that normal ΔPco2 was not dependent on CO2 washout by the villi microcirculation. Increased perfusion in deeper intestinal layers might be an alternative explanation.

Side-by-Side Alterations in Glycocalyx Thickness and Perfused Microvascular Density During Acute Microcirculatory Alterations in Cardiac Surgery.

OBJECTIVES: Endothelial glycocalyx injury causes microcirculatory perfusion disturbances in experimental studies, but the relevance in a clinical setting remains unknown. We investigated whether glycocalyx dimensions are reduced after onset of CPB and whether this is associated with alterations in microvascular perfusion. METHODS: The current observational study included 36 patients undergoing cardiac surgery without or with CPB, using either nonpulsatile or pulsatile flow. Sublingual microcirculatory perfusion was assessed perioperatively and analyzed for perfused vessel density and PBR, an inverse parameter of endothelial glycocalyx dimensions. RESULTS: Perfused vessel density decreased after onset of CPB in parallel with an increase in PBR in both pulsatile and nonpulsatile groups. In the nonpulsatile CPB group, these alterations were still persistent in the ICU (PVD: T1 19.8 ± 2.8 mm/mm(2) vs. T3 15.3 ± 2.6 mm/mm(2) ; p = 0.004. PBR: T1 2.40 ± 0.35 µm vs. T3 2.60 ± 0.31 µm; p = 0.020). In the off-pump group, perfused vessel density remained unaltered. An inverse correlation between perfused vessel density and PBR was detected. CONCLUSIONS: This study shows that endothelial glycocalyx dimensions decrease after onset of CPB and are closely related to microvascular perfusion when assessed with a novel, noninvasive technique.

A novel application of electrospinning technique in sublingual membrane: characterization, permeation and in vivo study.

Isosorbide dinitrate-polyvinylpyrrolidone (ISDN-PVP) electrospinning fibers were formulated and explored as potentially sublingual membrane. The addition of polyethylene glycol (PEG) to the formulation improved flexibility and reduced fluffiness of the fiber mat. The scanning electron microscopy (SEM) demonstrated that the fibers tended to be cross-linking, and the crosslinking degree increased with the increase of PEG amount. The differential scanning calorimetry (DSC) indicated that ISDN existed in non-crystalline state in the fibers (except at the highest drug content). The infrared spectroscopy suggested that ISDN had better compatibility with the ingredients owing to the hydrogen bonding (or hydrophobic interactions). The fibers were highly favorable for the fabrication of sublingual membrane due to neutral pH, large folding endurance and rapid drug release (complete dissolution within 120 s). The permeation study of ISDN through both dialysis membrane (DM) and porcine sublingual mucosa (SM) were carried out. A significant relationship of drug permeation rate through DM and SM was built up, which indicated that DM could be used to partly simulate SM and assess formulation. The pharmacokinetic study in rats demonstrated that the electrospinning fiber membrane had a higher Cmax and lower Tmax compared to the reference preparation, and the relative bioavailability of the fiber membrane was 151.6%.

In Vivo Capillary Loop Hemoglobin Spectroscopy in Labial, Sublingual, and Periodontal Tissues.

OBJECTIVE: Reproducible estimates of hemoglobin absorption spectra from human capillaroscopy images of arterioles, capillaries, and venules in sublingual and labial mucosa in vivo and venules in the tissues lining the periodontal pocket. METHOD: By reducing the size of both the imaging lens and the light guide to a maximum 1 mm diameter and opposing them with a gap of 600 µm we have been able to transmit light through the loop of tissues which moves into the gap between the lens and light guide when these are placed in contact with the labial and sublingual oral mucosa. This allows in vivo transillumination of the microvessels supplying the mucosa. RESULTS: Images from five volunteers showed similar patterns and the ratio of optical densities at 410 nm and 430 nm had a range from 2.5 at 90-100% saturation to 0.5 at zero % saturation. Measured optical density ratios ranged from 0.5 to 1.6 ± 0.1 in the afferent arm of the capillary loops and 0.5 to 1.1 ± 0.1 in the efferent arm of the capillary loops. CONCLUSION: In vivo spectroscopic hemoglobin optical density ratios in oral mucosal microvessels show a qualitatively consistent result within the expected in vitro parameters.

Microvascular glycocalyx dimension estimated by automated SDF imaging is not related to cardiovascular disease.

OBJECTIVE: The EG regulates vascular homeostasis and has anti-atherogenic properties. SDF imaging allows for noninvasive visualization of microvessels and automated estimation of EG dimensions. We aimed to assess whether microcirculatory EG dimension is related to cardiovascular disease. METHODS: Sublingual EG dimension was estimated by SDF imaging in healthy volunteers and in patients visiting an outpatient clinic for vascular medicine of a university hospital in Amsterdam, the Netherlands. EG dimension was compared among healthy volunteers, patients with CVD, and patients at low (<10%) or high risk (≥ 10%) of CVD according to the Framingham algorithm. RESULTS: In total 120 patients and 30 healthy volunteers were included. Patients had a mean age of 59 ± 14 years, 71 (59%) were men and 24 (20%) were black. Healthy volunteers were on average 28 ± 4 years and 19 (63%) were men. EG dimension was similar in healthy volunteers (2.04 ± 0.23 µm), low-risk patients (2.05 ± 0.24 µm, n = 39), high-risk patients (2.05 ± 0.23 µm, n = 30) and in patients with CVD (2.09 ± 0.21 µm, n = 51, p = 0.79). EG dimension was not correlated with cardiovascular risk factors. CONCLUSIONS: Microcirculatory EG dimension, as estimated by automated SDF imaging, is not associated with CVD, suggesting that this technique may not contribute to cardiovascular risk stratification.

Identification of mutations in the PYRIN-containing NLR genes (NLRP) in Head and Neck Squamous Cell Carcinoma.

Head and Neck Squamous Cell Carcinoma (HNSCC) encompasses malignancies that arise in the mucosa of the upper aerodigestive tract. Recent high throughput DNA sequencing revealed HNSCC genes mutations that contribute to several cancer cell characteristics, including dysregulation of cell proliferation and death, intracellular proinflammatory signaling, and autophagy. The PYRIN-domain containing NLR (Nucleotide-binding domain, Leucine rich Repeats - containing) proteins have recently emerged as pivotal modulators of cell death, autophagy, inflammation, and metabolism. Their close physiologic association with cancer development prompted us to determine whether mutations within the NLRP (PYRIN-containing NLR) gene family were associated with HNSCC genome instability and their clinicopathologic correlations. Catastrophic mutational events underlie cancer cell genome instability and mark a point-of-no-return in cancer cell development and generation of heterogeneity. The mutation profiles of 62 patients with primary conventional type HNSCC excluding other histologic variants were analyzed. Associations were tested using Fisher's Exact test or Mann-Whitney U test. Mutations in NLRP were associated with elevated genome instability as characterized by higher mutation rates. Clinically, NLRP mutations were more frequently found in HNSCC arising in the floor of mouth (50.0%) in comparison with HNSCC at other head and neck locations (14.8%). These mutations were clustered at the leucine rich repeats region of NLRP proteins, and affected NLRP genes were mostly localized at chromosomes 11p15.4 and 19q13.42-19q13.43. Twenty novel NLRP mutations were identified in HNSCC, and mutations in this group of genes were correlated with increased cancer cell genome mutation rates, and such features could be a potential molecular biomarker of HNSCC genome instability.

Dendritic cells of the oral mucosa.

The oral cavity contains distinct mucosal surfaces, each with its own unique distribution of dendritic cell (DC) subsets. In addition to tissue-specific properties, such organization might confer differential immune outcomes guided by tissue-resident DCs, which translate in the lymph node into an overall immune response. This process is further complicated by continual exposure and colonization of the oral cavity with enormous numbers of diverse microbes, some of which might induce destructive immunity. As a central cell type constantly monitoring changes in oral microbiota and orchestrating T-cell function, oral DCs are of major importance in deciding whether to induce immunity or tolerance. In this review, an overview of the phenotype and distribution of DCs in the oral mucosa is provided. In addition, the role of the various oral DC subsets in inducing immunity vs. tolerance, as well as their involvement in several oral pathologies is discussed.

[Incidence of odontogenic phlegmon associated with polymorphic variant 896A/G of gene TLR4, but not with 2258G/A of gene TLR2].

The problem actuality is caused by significant enhancement of the incidence rate for inflammatory diseases of the head and neck tissues, first of all of the oral cavity floor abscesses and phlegmons, which causes severe forms of mediastinitis while inadequate treatment. The authors have had established, that Toll-like receptors (TLR) initiate a cascade of anti-inflammatory reactions of the inborn immunity, followed by synthesis of a certain cytokines, and their genetic polymorphism changes the immune reactivity of the organism. Trustworthy correlation of the gene TLR4 (rs4986790) polymorphism 896A/G was proved with high risk of the odontogenic phlegmon of the oral cavity floor occurrence, what would permit to prognosticate the disease course in early terms, to optimize the schemes of its prophylaxis and treatment.

A comparative study of microvessel density in squamous cell carcinoma of the oral cavity and lip.

OBJECTIVES: The objective of this study was to comparatively evaluate the density of lymphatic vessels (LVD) and neoformed microvessels (NMVD) in squamous cell carcinoma of the oral cavity (OCSCC) and lip (LSCC). Association between LVD/NMVD and vascular endothelial growth factor (VEGF)-A/-C was also assessed. STUDY DESIGN: OCSCC and LSCC were compared with regard to immunoexpression of LVD, NMVD, and vascular endothelial growth factor-A (VEGF)-A/-C. Association between VEGF-A/-C with vascularity was also assessed. Statistical analyses were performed using t test, Pearson χ(2), and Mann-Whitney tests. Statistical significance was accepted at P less than .05. RESULTS: The NMVD and VEGF-C expressions were significantly higher in OCSCC compared with LSCC. NMVD was associated with VEGF-C in OCSCC, but not in LSCC. CONCLUSIONS: Differences in NMVD and VEGF-C were found between OCSCC and LSCC. Positive association between VEGF-C and NMVD was observed in OCSCC, but not in LSCC, which may be one of the contributing factors that account for the distinctive clinical-biological behavior of these lesions.

Correlation of metabolism/hypoxia markers and fluorodeoxyglucose uptake in oral squamous cell carcinomas.

OBJECTIVE: The objective of this study was to analyze the relationship between the uptake of (18)F-2-fluoro-2-deoxy-d-glucose (FDG) by positron emission tomography-computerized tomography (PET-CT) and glucose metabolism/hypoxia markers in oral squamous cell carcinoma (OSCC). STUDY DESIGN: Thirty-six patients with OSCC (tongue [n = 23], buccal mucosa [n = 7], and floor of the mouth [n = 6]) were assessed and underwent incisional biopsy and subsequently received FDG-PET-CT. Expressions of hypoxia-inducible factor 1α (HIF-1α), glucose transporter protein 1 (GLUT-1), hexokinase-II (HK-II), and glucose-6-phosphatase (G6Pase) were immunohistochemically quantified, and FDG uptake was evaluated by the maximum standardized uptake values (SUV(max)) at the primary tumor site. RESULTS: FDG uptake was found to be significantly correlated with the T classification of OSCC but not with other clinicopathologic characteristics, such as the N classification, clinical type, and histologic grade of malignancy. In the early-stage (T1 and T2) tumor, FDG uptake was significantly associated with the expression levels of GLUT-1, HK II, and HIF-1α, and the expression levels of GLUT-1 and HK-II significantly correlated with HIF-1α expression levels. However, there were no correlations between the expression levels of these molecules and SUV(max) in the late-stage (T3 and T4) tumor. CONCLUSIONS: FDG uptake was significantly associated with the expression levels of glucose metabolism-related molecules, such as GLUT-1, HK II, and HIF-1α, especially in early-stage tumors.

Gene and protein expressions of vimentin and desmin during embryonic development of the mylohyoid muscle.

Meckel's cartilage is known to be involved in formation of the prenatal mandible. However, the relationship between Meckel's cartilage and the embryonic mylohyoid muscle during growth and development has been investigated only rarely. This study examined the expression of intermediate filaments in Meckel's cartilage and the embryonic mylohyoid muscle in fetal mice during morphological development. Specimens of E12-16 ICR mice sectioned in the frontal direction were subjected to immunohistochemistry for vimentin and desmin. Hematoxylin and eosin sections showed that the immature mylohyoid muscle began to grow along Meckel's cartilage during fetal development. Weak vimentin expression was detected in the mylohyoid muscle and surrounding tissues at E12. Desmin expression was detected specifically in the mylohyoid, and strong expression was evident after E13, and increased with age. It was inferred that the mylohyoid muscle is one the tissues developing from Meckel's cartilage, the latter exerting a continuous influence on the growth of the former. In the early stage, the surrounding mesenchymal tissues expressing vimentin formed a scaffold for the developing mylohyoid muscle. Muscle attachment at E13 showed steady desmin expression, which continued until maturity. This study suggested the possibility that Meckel's cartilage has an influence not only on the mandibular bone, but also on the development of the mylohyoid muscle attached to the mandibular bone. Furthermore, it revealed a stage of the developmental process of the mylohyoid muscle in which the expression of vimentin, which is a common protein in the surrounding tissue such as muscle and bone, induces the morphological formation of the mylohyoid muscle, cooperating with the surrounding structures.

In vitro permeation of mesembrine alkaloids from Sceletium tortuosum across porcine buccal, sublingual, and intestinal mucosa.

Sceletium tortuosum is an indigenous South African plant that has traditionally been used for its mood-enhancing properties. Recently, products containing S. tortuosum have become increasingly popular and are commonly administered as tablets, capsules, teas, decoctions, or tinctures, while traditionally the dried plant material has been masticated. This study evaluated the in vitro permeability of the four major S. tortuosum alkaloids (i.e., mesembrine, mesembrenone, mesembrenol, and mesembranol) across porcine intestinal, sublingual, and buccal tissues in their pure form and in the form of three different crude plant extracts, namely water, methanol, and an acid-base alkaloid-enriched extract. The permeability of mesembrine across intestinal tissue was higher than that of the highly permeable reference compound caffeine (which served as a positive control for membrane permeability) both in its pure form, as well as in the form of crude extracts. The intestinal permeability of mesembranol was similar to that of caffeine, while those of mesembrenol and mesembrenone were lower than that of caffeine, but much higher than that of the poorly permeable reference compound atenolol (which served as a negative control for membrane permeability). In general, the permeabilities of the alkaloids were lower across the sublingual and the buccal tissues than across the intestinal tissue. However, comparing the transport of the alkaloids with that of the reference compounds, there are indications that transport across the membranes of the oral cavity may contribute considerably to the overall bioavailability of the alkaloids, depending on pre-systemic metabolism, when the plant material is chewed and kept in the mouth for prolonged periods. The results from this study confirmed the ability of the alkaloids of S. tortuosum in purified or crude extract form to permeate across intestinal, buccal, and sublingual mucosal tissues.

Distinct expression of perforin and granzyme B in lip and oral cavity squamous cell carcinoma.

BACKGROUND: Perforin and granzyme B (GB) are the main constituents of cytotoxic T-lymphocyte granules, and they have important roles in preventing the initiation and progression of cancer. METHODS: The aim of this study was to compare the expression of CD8(+) /perforin(+) double-staining and GB(+) cells, by immunohistochemistry, in primary oral cavity squamous cell carcinoma (OCSCC), lip squamous cell carcinoma (LSCC), non-dysplastic leukoplakia (LK), dysplastic LK, actinic cheilitis (AC), oral lichen planus (LP) and normal oral mucosa. RESULTS: Our results showed a higher expression of CD8(+) /perforin(+) and GB(+) cells in LSCC when compared with the samples of OCSCC, non-dysplastic and dysplastic LK, AC, oral LP and normal oral mucosa. In addition, increased CD8(+) /perforin(+) and GB(+) cell numbers were observed in all pre-malignant lesions (non-dysplastic LK, dysplastic LK, AC) when compared with the control. CONCLUSIONS: Perforin and GB proteins may contribute to antitumoural immunity, leading to the direct killing of tumour cells; however, it seems to occur more effectively in LSCC than OCSCC.

Oral lyophilisate and food immunotherapy: from research to clinical practice

Thanks to its excellent safety profile, sublingual immunotherapy has served as a basis for launching two important lines of research in current allergology: sublingual immunotherapy with pharmaceutical registry (oral lyophilizates or tablets), and sublingual immunotherapy with food. At present, clinical trials are being conducted which use rapid dissolution oral lyophilizates. The results of the clinical trials carried out in large patient groups and based on a double-blind methodological design have allowed pharmaceutical registry of this form of treatment, with the therapeutic indications of rhinitis and allergy to grasses. Phleum lyophilizate indicated for the treatment of rhinoconjunctivitis will be marketed in Spain in the coming months. In parallel to development of the sublingual route, advances in our knowledge of pollen allergy and its relationship to plant food allergies have facilitated the conducting of studies involving sublingual immunotherapy for allergy to kiwi fruit, hazel nut and peach – thus giving rise to promising future perspectives for affected patients

No disponible

Validation of diagnostic tests for determination of magnesium status in horses with reduced magnesium intake.

OBJECTIVE: To evaluate the diagnostic value of serum concentrations of total magnesium (tMg) and ionized magnesium (iMg), concentrations of magnesium (Mg) in muscle, intracellular Mg (icMg) concentrations, urinary Mg excretion (EMg), Mg clearance (CMg), and fractional clearance of Mg (FCMg) in horses fed diets with Mg content above and below National Research Council recommendations. ANIMALS: 9 young female horses. PROCEDURES: 6 horses were fed a reduced-Mg diet for 29 days followed by an Mg-supplemented diet for 24 days. Control horses (n = 3) were fed grass hay exclusively. Blood, urine, and tissue samples were collected, and an Mg retention test was performed before and after restriction and supplementation of Mg intake. Serum tMg, serum iMg, muscle Mg, icMg, and urine Mg concentrations were measured, and 24-hour EMg, CMg, and FCMg were calculated. RESULTS: Reductions in urinary 24-hour EMg, CMg, and FCMg were evident after 13 days of feeding a reduced-Mg diet. Serum tMg and iMg concentrations, muscle Mg content, and results of the Mg retention test were not affected by feeding the Mg-deficient diet. Spot urine sample FCMg accurately reflected FCMg calculated from 6- and 24-hour pooled urine samples. Mean +/- SD FCtMg of horses eating grass hay was 29 +/- 8%, whereas mean FCtMg for horses fed a reduced-Mg diet for 29 days was 6 +/- 3%. CONCLUSIONS AND CLINICAL RELEVANCE: The 24-hour EMg was the most sensitive indicator of reduced Mg intake in horses. Spot sample FCMg can be conveniently used to identify horses consuming a diet deficient in Mg.

Comparative permeability of various chemical markers through human vaginal and buccal mucosa as well as porcine buccal and mouth floor mucosa.

A number of drugs undergo extensive first-pass metabolism after oral administration, necessitating large doses for effective therapeutic responses in the body. Buccal administration of drugs is becoming more popular because the drugs diffuse into the systemic circulation directly, circumventing the first-pass metabolism. Lower concentrations thus need to be administered and side effects may be minimized. In this study, one of the classic models for human buccal permeability, i.e. the porcine buccal mucosal model, is compared with the more recent human vaginal model and both these are in turn further compared to porcine mouth floor mucosa. To determine the permeability of the different markers (arecoline, 17beta-estradiol, water and vasopressin), a continuous flow-through perfusion system was used (20 degrees C, 24h). Mean steady state flux values were compared statistically using a t-test at a significance level of 5%. Porcine buccal mucosa showed a consistently lower permeability towards all the markers than the other mucosae tested. Porcine mouth floor mucosa was found to be more permeable than porcine buccal mucosa. From these studies we concluded that human vaginal and porcine mouth floor mucosae were superior models for human buccal mucosa than porcine buccal mucosa, using in vitro permeability studies with various chemical markers.

Absorción transbucal de fármacos / Transbuccal permeation of drugs

En este trabajo se analiza la cavidad oral cómo lugar potencial para la administración de fármacos (sublingual y bucal) con el fin de obtener efectos tanto a nivel sistémico como a nivel local. Además, se evalúan una serie de parámetros que intervienen en el proceso de absorción como: los mecanismos involucrados, las diferencias en la permeabilidad de las mucosas que la constituyen, las características físico-químicas del fármaco, factores fisiológicos y patológicos que influyen en la permeabilidad y factores farmacotécnicos a considerar a la hora de diseñar esta clase de sistemas. La administración sublingual de pequeñas moléculas da lugar a una rápida absorción y a una buena biodisponibilidad, aunque esta vía no constituye una zona adecuada para la aplicación de sistemas de liberación sostenida. Sin embargo, la mucosa bucal a pesar de ser menos permeable, sí que constituye un lugar adecuado para la aplicación de esta clase de sistemas. Por estas razones, la mucosa bucal podría reunir las condiciones necesarias para la administración de péptidos, preferentemente aquellos con bajo peso molecular, alta potencia y larga semivida plasmática. Por otro lado, la administración de fármacos con el fin de obtener efectos a nivel local no se ha estudiado de forma muy detallada. En este último caso los factores a considerar son los mismos que los que se tienen en cuenta cuando se pretende obtener efectos sistémicos (AU)