Changes in Intestinal Permeability after Roux-en-Y Gastric Bypass

Background

Roux-en-Y gastric bypass (RYGB) interferes considerably with the anatomy and physiology of the gastrointestinal tract. The study of intestinal permeability can provide important information regarding changes in the structure and function of the mucosal barrier after the procedure.

Methods

The urinary excretion rates of lactulose and mannitol after oral intake of both substances were evaluated. We also evaluated the lactulose/mannitol excretion ratio. Tests were performed during the preoperative period (T0), at the first postoperative month (T1), and at the sixth postoperative month (T6).

Results

The study included 16 morbidly obese patients. The excretion rate of mannitol was significantly lower at T1 compared with T0 and T6 (p?=?0.003). There was no significant difference in the excretion rates of lactulose or in the lactulose/mannitol ratio during the three periods. Six patients (37.5 %) exhibited a considerable increase in the excretion rate of lactulose at T6 (4–73 times higher than the preoperative value), accompanied by proportional variations in the lactulose/mannitol ratio.

Conclusions

The significant increase in mannitol excretion rate from T1 to T6 most likely reflects the occurrence of intestinal adaptation (mucosal hyperplasia), which would tend to minimize the malabsorption of macronutrients. A subgroup of patients who undergo RYGB exhibit pronounced increase in their intestinal permeability (assessed by the lactulose/mannitol ratio and the lactulose excretion rate) at T6.     

Photodynamic therapy associated with full-mouth ultrasonic debridement in the treatment of severe chronic periodontitis: a randomized-controlled clinical trial

Background:

Photodynamic therapy (PDT) is a method of microbial reduction which can benefit periodontal treatment in areas of difficult access, such as deep pockets and furcations. The aim of this randomized controlled clinical trial was to evaluate the effects of PDT as an adjunct to full-mouth ultrasonic debridement in the treatment of severe chronic periodontitis.

Material and Methods:

Twenty-two patients with at least one pocket with a probing depth (PD) of ≥7 mm and one pocket with a PD of ≥5 mm and bleeding on probing (BOP) on each side of the mouth were included, characterizing a split mouth design. The control group underwent full-mouth ultrasonic debridement and the test group received the same treatment associated with PDT. The PDT was performed on only one side of the mouth and the initial step consisted of subgingival irrigation with 0.005% methylene blue dye. Two minutes after applying the photosensitizer, the low power laser - AsGaAl (Photon Lase III - PL7336, DMC, São Carlos -São Paulo, Brazil) was applied (660 nm, 100 mW, 9 J, 90 seconds per site, 320 J/cm², diameter tip 600 µm).The following clinical parameters were evaluated: plaque index, gingival index, BOP, gingival recession (GR), PD, and clinical attachment level (CAL). All parameters were collected before, 1, 3 and 6 months after treatment.

Results:

An improvement in BOP, PD and CAL was observed after treatment, in both groups, but without any difference between them. After 6 months, the PD decreased from 5.11±0.56 mm to 2.83±0.47 mm in the test group (p<0.05) and from 5.15±0.46 mm to 2.83±0.40 mm in the control group (p<0.05). The CAL changed, after 6 months, from 5.49±0.76 mm to 3.41±0.84 mm in the test group (p<0.05) and from 5.53±0.54 to 3.39±0.51 mm in the control group (p<0.05).

Conclusion:

Both approaches resulted in significant clinical improvements in the treatment of severe chronic periodontits, however, the PDT did not provide any additional benefit to those obtained with full-mouth ultrasonic debridement used alone.     

Specific correction of impaired acid hydrolase secretion in storage pool-deficient platelets by adenosine diphosphate.

Storage pool-deficient (SPD) platelets, which have decreased amounts of dense-granule and/or alpha-granule constituents, contain normal amounts of lysosomal acid hydrolases, but in some cases exhibit impaired secretion of these enzymes. We examined this impaired secretion response in SPD patients with varying extents of granule deficiencies, and determined the effects of added dense-granule constituents. Acid hydrolase secretion was impaired in patients with severe dense-granule deficiencies, but not in patients with lesser dense-granule deficiencies, including those with alpha-granule deficiencies as well. When dense-granule constituents (ADP, ATP, serotonin, Ca+2, pyrophosphate) were added to gel-filtered platelets, ADP, but none of the other constituents, completely corrected the impairment of thrombin and A23187-induced secretion in SPD platelets. The concentration of ADP required to normalize thrombin-induced secretion varied markedly, from 0.01 to 10 microM, among the individual patients. Fixation of platelets with formaldehyde before centrifugation did not prevent the enhancement of secretion by ADP. Excess ATP, which acts as a specific antagonist of ADP-mediated responses, completely blocked this enhancement of secretion in SPD platelets by ADP, and partially inhibited acid hydrolase secretion induced by low, but not high, concentrations of thrombin in normal platelets as well. Treatment of normal platelets with acetylsalicylic acid in vivo, but not in vitro, produced an impairment of acid hydrolase secretion similar in extent to that in SPD platelets, but which could not be completely corrected by added ADP. One possible explanation of these results is that the impairment of acid hydrolase secretion may be secondary to the dense-granule deficiency in SPD platelets, and that secreted ADP may potentiate the lysosomal secretion response in normal platelets as well.     

Original Article: Comparison of A23187 vs Ionomycin-induced Responses and Cytosolic Calcium Increases in Aequorin-loaded Human Platelets. Evidence for Ionophore-specific Differences in Intracellular Calcium Release

The dose-dependent induction of platelet aggregation, dense granule secretion and thromboxane formation by the divalent cation ionophores A23187 and ionomycin were compared in citrated platelet rich plasma (PRP), and measured simultaneously with the increases in cytosolic Ca(2+) levels in aequorin-loaded gel-filtered platelet (GFP). In citrated PRP, both ionophores induced similar extents of aggregation at comparable concentrations, whereas A23187 induced somewhat greater extents of secretion, and substantially greater extents of thromboxane B(2) (TxB(2)) formation, than ionomycin. When 5 mM EDTA or EGTA was added to PRP secretion and TxB(2) formation occurred only with A23187; ionomycin was inactive at all concentrations tested, up to 100 pM. In aequorin-loaded GFP containing 1 mM Ca(2+), 1 mM EGTA or 2 mM EDTA, ionomycin as well as A23187 induced these platelet responses, but the concentration dose-response curve for ionomycin was shifted to the right by approximately one order of magnitude relative to that for A23187. Simultaneous measurements of the cytosolic Ca(2+) ([Ca(2+)](1)) increases induced by the two ionophores showed that the increases produced by ionomycin were consistently 2040% less than those induced by A23187 at all ionophore concentrations tested. Analysis of the extents of secretion and TxB, formation obtained in EDTA- or EGTA-containing systems as a function of the [Ca(2+)](1) increases suggested that the data for both ionophores were described by the same [Ca(2+)](1) dose-response curve, indicating that the decreased extents of these responses seen with ionomycin vs A23187 were due primarily, if not solely, to the lower [Ca(2+)], increases produced by ionomycin. Since ionomycin is theoretically capable of transporting twice as much divalent cation as A23187, these findings in platelets, together with similar findings in certain other cell systems, provide evidence that factors associated with the intracellular environment may differentially affect the abilities of A23187 and ionomycin to induce cellular responses and, more specifically, to release intracellular Ca(2+) stores.     

Agreement between adolescents and parents/caregivers in rating the impact of malocclusion on adolescents' quality of life

Objective:To assess the agreement between adolescents and their parents/caregivers regarding the impact of malocclusion on adolescents'' oral health–related quality of life (OHRQoL).Materials and Methods:A consecutive sample of 141 adolescent and parent/caregiver pairs was selected. Adolescents answered the short version of the Child Perceptions Questionnaire (CPQ_11–14), while parents answered the Parental-Caregiver Perceptions Questionnaire (P-CPQ). The CPQ_11–14 and the P-CPQ have 14 items in common that are organized through four subscales: oral symptoms (OS), functional limitations (FL), emotional well-being (EW), and social well-being (SW). Agreement on the overall score and agreement on the subscales were determined using comparison and correlation analysis. The comparison analysis was carried out by comparing the mean directional and absolute differences, and the correlation analysis was performed using the intraclass correlation coefficient (ICC).Results:A total of 135 pairs of adolescents and parents/caregivers agreed to answer the questionnaires, providing a response rate of 95.7%. The mean age of the adolescents was 11.50 years. The mean directional difference was significant for the OS (P < .001) and FL (P = .040) subscales as well as for the overall score (P = .007). Adolescents'' reports were higher than parents/caregivers'' reports. The mean absolute difference for the overall score was 7.26, representing 12.9% of the maximum possible overall score. The ICC was 0.16 for the overall score, indicating poor agreement.Conclusion:Poor agreement was observed between adolescents and their parents/caregivers in rating the impact of malocclusion on adolescents'' OHRQoL.     

Decreased content and surface expression of alpha-granule membrane protein GMP-140 in one of two types of platelet alpha delta storage pool deficiency.

To determine whether alpha-granule membranes are present in platelets of patients with storage pool deficiencies of both alpha and dense granules (alpha delta-SPD), we examined the content and surface expression of the alpha-granule membrane protein GMP-140 in one patient (J.C.) with a severe alpha-granule deficiency and in three members of a family (family C) with milder alpha-granule deficiencies. Surface expression of GMP-140 in stimulated platelets, assessed by flow cytometric measurements of the binding of two anti-GMP-140 monoclonal antibodies, was 24-38% of normal values in platelets from patient J.C., vs. 60-95% of normal values in family C. Total platelet content of GMP-140, determined in platelet lysates by antigen-capture ELISA, was 49% of normal in patient J.C., but normal in the members of family C. Platelets of patient J.C. were found to be heterogeneous with respect to GMP-140 content and surface expression by both flow cytometry and immunogold electron microscopy. Approximately 80% of her platelets expressed little or no GMP-140 after stimulation, whereas the remaining 20% expressed normal amounts of GMP-140 and showed extensive immunogold labeling of typical alpha-granules and clear vacuoles. No such heterogeneity was found in platelets from family C. These findings in the severe alpha delta-SPD patient are in clear contrast to the observations of normal GMP-140 content in the three other alpha delta-SPD patients, and in patients with the gray platelet syndrome, reported previously by others. These results illustrate the phenotypic heterogeneity of alpha-granule deficiencies in human platelets, and suggest that a defect in granule formation in the megakaryocytes may account for the alpha-granule defect in at least one form of alpha delta-SPD.     

Heterogeneous abnormalities of platelet dense granule ultrastructure in 20 patients with congenital storage pool deficiency

Studies on platelet dense granule structure were carried out in 20 patients with various types of congenital storage pool deficiency (SPD), including 15 with specific deficiencies of dense granules and dense granule substances (δ-SPD), and five with combined deficiencies of dense and α-granules (αδ-SPD). Dense granules were identified by their high affinity for uranyl ions (uranaffin reaction), by their ability to accumulate the fluorescent dye mepacrine, and by their inherent electron opacity on unfixed, unstained whole mount preparations. By all these methods, dense granules were markedly decreased in seven albino patients with the Hermansky-Pudlak syndrome (HPS) variant of δ-SPD. These findings suggest that the basic defect in these patients is a specific abnormality in organelle development which prevents the formation of an intact granule structure, a quantitative abnormality which may differ from that in animals with related pigment disorders. In contrast, eight non-albino patients with δ-SPD had, on average, only a slightly reduced number of uranaffin-positive and mepacrine-positive granules, but a shift in uranaffin-granule distribution towards those lacking a dense core (‘empty granules’), suggesting a more qualitative type of dense granule defect. These results are consistent with previous evidence suggesting a decreased uptake of ATP across the granule membrane in δ-SPD. In addition, on whole mounts, these patients’platelets contained substantial numbers of electron dense chains and clusters which contained P and Ca, but with a P/Ca ratio less than that of typical dense granules, and which were retained, along with a larger amount of ATP, after thrombin treatment of the platelets. The various findings in these patients raise the possibility that these structures may represent microvesicles, derived from the Golgi apparatus, which provide a transport mechanism for concentrating adenine nucleotides and calcium in dense granules and which is impaired in some patients with SPD. Additional defects may account for the more extensive granule abnormalities observed in αδ-SPD.