Comparison of hygiene levels in metal-ceramic and stratified zirconia in prosthetic rehabilitation on teeth and implants: a retrospective clinical study of a three-year follow-up.

The aim of this retrospective clinical study was to evaluate and compare oral hygiene levels in patients subjected to fixed metal-ceramic or stratified zirconia prostheses, either on teeth or on dental implants. Twenty patients, including 10 with metal-ceramic prostheses and 10 with stratified zirconia, were engaged for the study. Considering the prosthesis positioning phase as zero time, all patients were examined twice a year for a follow-up period of 3 years. During each session, to assess oral cavity state of health, both the Plaque Index (IP) and the Bleeding Index (BOP) were recorded. All patients were instructed in home hygiene maintenance and subjected to professional oral hygiene sessions customized according to prothesis type (on natural teeth or dental implants) and materials (metal ceramic or stratified zirconia). Statistically significant evidence was found in IP values, with an increase in the initial stages in zirconia prostheses and in the final stages in metal-ceramic ones. BOP levels showed a reduction during the follow-up period, but no statistically significant differences were found between examined groups. An adequate patient education in hygiene maintenance associated with professional oral hygiene sessions with special tools could positively affect fixed prostheses' maintenance, both on natural teeth and on dental implants.

Application of the "immunization islands" model to improve quality, efficiency and safety of a COVID-19 mass vaccination site.

Abstract: After SARS-CoV-2 vaccines development came at an unprecedented speed, ensuring safe and efficient mass immunization, vaccine delivery be-came the major public health mandate. Although mass-vaccination sites have been identified as essential to curb COVID-19, their organization and functioning is challenging. In this paper we present the planning, implementation and evalua-tion of a massive vaccination center in Lombardy - the largest Region in Italy and the most heavily hit by the pandemic. The massive hub of Novegro (Milan), managed by the Gruppo Ospedaliero San Donato, opened in April 2021. The Novegro mass-immunization model was developed building a la-yout based on the available scientific evidence, on comparative analysis with other existing models and on the experience of COVID-19 immunization delivery of Gruppo Ospedaliero San Donato. We propose a "vaccine islands" mass-immunization model, where 4 physicians and 2 nurses operate in each island, with up to 10 islands functioning at the same time, with the capacity of providing up to 6,000 vaccinations per day. During the first week of activity a total of 37,900 doses were administered (2,700/day), most of them with Pfizer vaccine (85.8%) and first doses (70.9%). The productivity was 10.5 vaccines/hour/vaccine station. Quality, efficiency and safety were boosted by ad-hoc personnel training, quality technical infrastructure and the presence of a shock room. Constant process monitoring allowed to identify and promptly tackle process pitfalls, including vaccine refusals (0.36%, below expectations) and post-vaccinations adverse reactions (0.4%). Our innovative "vaccine islands" mass-immunization model might be scaled-up or adapted to other settings. The Authors consider that sharing best practices in immunization delivery is fundamen-tal to achieve population health during health emergencies.

Evaluation of the morphometric covariation between palatal and craniofacial skeletal morphology in class III malocclusion growing subjects.

BACKGROUND: To study the covariation between palatal and craniofacial skeletal morphology in Class III growing patients through geometric morphometric analysis (GMM). METHODS: In this retrospective study, 54 Class III subjects (24F,30M;7.6 ± 0.8yy) were enrolled following these inclusion criteria: European ancestry, Class III skeletal and dental relationship, early mixed dentition, prepubertal skeletal maturation, familiarity for Class III malocclusion, no pseudo Class III malocclusion. Each patient provided upper digital cast and cephalogram before starting the therapy. Landmarks and semilandmarks were digitized (239 on the casts;121 on the lateral radiographs) and GMM was used. Procrustes analysis and principal component analysis (PCA) were applied to show the principal components of palatal and craniofacial skeletal shape variation. Two-block partial least squares analysis (PLS) was used to assess pattern of covariation between palatal and craniofacial morphology. RESULTS: Regarding palatal shape variation, PC with largest variance (PC1) described morphological changes in the three space dimensions, while, concerning the craniofacial complex components, PC1 revealed morphological differences along the vertical plane. A significant covariation was found between palatal and craniofacial shape. PLS1 accounted for more than 61,7% of the whole covariation, correlating the craniofacial divergence to palatal height and width. CONCLUSIONS: In Class III subjects increments of angle divergence are related to a narrow and high palate.

Palatal prosthetic rehabilitation in patients affected by cocaine-induced midline destructive lesions.

Cocaine is one of the most popular illicit drugs in Europe and cocaine-induced midline destructive lesions (CIMDL) represent a rare but destructive consequence of its intranasal use. The extent of lesions can vary remarkably and may include palate perforations with consequent oronasal reflux and hypernasal speech. The therapeutic options encompass surgery, with local and distant flaps, and prosthetic rehabilitation with palatal obturators. We retrospectively reviewed a case series of 6 patients affected by palatal perforation as part of CIMDL, who were treated with a dental or implant-retained palatal obturator at San Raffaele Dentistry Department between 2015 and 2020. In addition, we reviewed the available literature on CIMDL and the prosthetic rehabilitation of palatal perforations in this context. The most frequent symptoms reported were hypernasal speech, oro-nasal reflux, halitosis, and difficulty in interpersonal relationships. Palatal obturators were always successful in the relief of the majority of symptoms, but the duration of the benefit was strongly related to progression of the lesion, and in some cases a close follow-up and continuous modifications of the prosthesis were necessary. In conclusion prosthetic approach is a valid option for the symptomatic relief in CIMDL-related palate perforation. Nevertheless, the short-lasting efficacy for patients with active disease can be the reason for unsatisfactory results.

Prosthetic management of patients with oro-maxillo-facial defects: a long-term follow-up retrospective study.

INTRODUCTION: The aim of this study is to determine the outcome of maxillofacial prosthetic rehabilitation after oncological resections, including both intra- and extra-oral prosthetic devices. METHODS: In this study were included 72 patients, who have undergone an intra or extra-oral maxillofacial prosthetic rehabilitation after an oncologic resection. Tumors on the head and neck were analyzed and the defects of these resections have been divided in two different groups: intra and extra-oral defects. RESULTS: 72 participants were treated with maxillofacial prosthesis, 3 of which with post-traumatic wounds and 69 with resections of tumors on the head and neck. Of the 69 treated for neoplastic disease, 43 received an intraoral prosthesis (palatal obturator) and 29 with an extraoral epithesis (18 with nasal prostheses, 8 with orbital implants and 3 with ear implants). The group included patients with different types of tumors. All the patients were evaluated in terms of aesthetic appearance after the construction of the prostheses and the results were satisfactory. CONCLUSION: Within the limitations of this study, after the use of maxillofacial protheses patients feel more confident and self-assured. Maxillofacial protheses are a good solution in order to improve the life's quality in patients with tumors resections: prostheses are easy to handle and provide a satisfying social interaction for the patients.

A New Total Digital Smile Planning Technique (3D-DSP) to Fabricate CAD-CAM Mockups for Esthetic Crowns and Veneers.

Purpose. Recently, the request of patients is changed in terms of not only esthetic but also previsualization therapy planning. The aim of this study is to evaluate a new 3D-CAD-CAM digital planning technique that uses a total digital smile process. Materials and Methods. Study participants included 28 adult dental patients, aged 19 to 53 years, with no oral, periodontal, or systemic diseases. For each patient, 3 intra- and extraoral pictures and intraoral digital impressions were taken. The digital images improved from the 2D Digital Smile System software and the scanner stereolithographic (STL) file was matched into the 3D-Digital Smile System to obtain a virtual previsualization of teeth and smile design. Then, the mockups were milled using a CAM system. Minimally invasive preparation was carried out on the enamel surface with the mockups as position guides. Results. The patients found both the digital smile design previsualization (64.3%) and the milling mockup test (85.7%) very effective. Conclusions. The new total 3D digital planning technique is a predictably and minimally invasive technique, allows easy diagnosis, and improves the communication with the patient and helps to reduce the working time and the errors usually associated with the classical prosthodontic manual step.

ENDOTHELIAL PROGENITOR CELL ADHESION, GROWTH AND CHARACTERIZATION ON TRABECULAR TITANIUM AND TRABECULAR TITANIUM COATED WITH COLLAGEN OR DECELLULARIZED ECM.

Adequate blood supply is essential for prosthesis osteointegration and bone healing as it supplies oxygen, nutrition and progenitor cells. The bone healing process and vascularization depend upon the endothelial cells, which speed up implant osteointegration. Endothelial Progenitor Cells (EPC) are a population of stem cells that can reproduce, migrate and acquire mature endothelial phenotype. Their recruitment occurs in the tissue lesion to enhance neovascularization. Trabecular TitaniumTM (TTTM) is a new biomaterial with very interesting biomechanical characteristics and fast osteointegration. This study has investigated adhesion, proliferation and characteristics of EPC on three types of biomaterial: unmodified trabecular titanium, trabecular titanium coated with the ECM deposited by human mesenchymal stem cells isolated from subcutaneous adipose tissue and decellularized and trabecular titanium coated with type I collagen (control scaffold). MTT assay showed similar percentages of EPCs seeded on the different kinds of scaffold: 67% on TT, 70% on decellularized scaffolds and 82% on collagen-coated scaffolds. There were no statistically significant differences between the three groups. We therefore conclude that TTTM allows EPC adhesion and proliferation and, consequently, by permitting vascularization, it favours prosthesis osteointegration.

Fiber reinforced composites orthodontic retainers.

AIM: Retention is the phase of orthodontic treatment that attempts to hold teeth in their corrected positions after orthodontic therapy is completed. The aim of this study was to consider fiber-reinforced composites (FRC) as a possible alternative to conventional multistranded stainless steel wire for retention through SEM analysis. METHODS: Two different FRC orthodontic retainers were investigated, i.e. Everstick® (Stick Tech Ltd, Turku, Finland) (type A, 24 samples), with a diameter of 0.76 mm made of glass fibers and a Young's modulus of elasticity of 28 gpa, and Ribbond® (Ribbond, Inc., Seattle, Washington, WA, USA) (type B, 24 samples), with ultra high molecular weight and with an high Young's modulus of elasticity by polyethylene fibers cold treated with plasma gas. Six groups were created: control groups A1 and B1, composed by 8 type A and 8 type B samples without impregnation and only with fluid resin before curing; groups A2 and B2, composed respectively by 8 type A and 8 type B samples impregnated with fluid resin Heliobond for 6 seconds; groups A3 and B3, composed respectively by 8 type A and 8 type B samples impregnated with fluid resin Heliobond for 6 minutes before curing. RESULTS: Cross- and lengthwise SEM analysis of the sectioned samples made showed that fiber without impregnation with fluid resin, before curing, showed interwoven and straight directed cylindrical fibers. The SEM analysis denoted that the two types of fiber shows structural characteristics differing in dimension, number, diameter and orientation of FRC without a preliminary treatment through impregnation of the fibers with fluid resin. CONCLUSION: An impregnation time of 6 seconds could considerably reduced voids, crazes and microcracks of the fibers, making them more resistant to the other oral and bacterial agents. A larger time of impregnation (6 minutes), with fluid resin before hardening, further enhances the morphological characteristics of the FRC.

[Insulin therapy and parenteral nutrition in intensive care: practical aspects]. / Insulinothérapie et nutrition parentérale en soins intensifs: aspects pratiques.

Critically ill patients are hypercatabolic due to stress and inflammation. This condition induces hyperglycemia. Muscle wasting is intense during critical illness. Its prevention is essential. This is possible by early and appropriate nutritional support. Preserving the function of the gastrointestinal tract with enteral nutrition is the gold standard. However, when targeted protein-caloric intake is not met through enteral nutrition within the first three days in the intensive care unit (ICU), supplemental parenteral nutrition is administered to reduce morbidity and mortality. In addition, in order to limit metabolic imbalance and reduce mortality, glycemic control using insulin therapy is mandatory. This article reviews the current understanding of parenteral nutrition and insulin therapy in ICU patients, and provides the decision model applied in our institution.

[Transition in diabetology]. / Transition en diabétologie.

For patients with type I diabetes, transition from pediatric to adult care is a challenge due to complex treatment requirements and the physical, psychological and social changes of adolescence. Members of the care team must recognize that while these emerging adults need to develop self-management skills, this may conflict at times with the developmentally appropriate desire for increasing autonomy. The role of nursing in coordinating a successful transition is critical for maintaining continuity of patient-centered care that responds to the specific needs of these young adults.

Osteogenic differentiation and gene expression of dental pulp stem cells under low-level laser irradiation: a good promise for tissue engineering.

The effects of low-level laser therapy (LLLT) has been the focus of recent studies as being assumed responsible for promoting photostimulatory and photobiomodulatory effects in vivo and in vitro, increasing cell metabolism, improving cell regeneration and invoking an anti-inflammatory response. A positive effect of LLLT on the bone proliferation of some cell types has been observed, but little is known about its effect on dental pulp stem cells (DPSCs). Here, we accurately describe the technical procedure to isolate mesenchymal DPSCs, and assay their osteogenic capacity when irradiated with an LLLT source. These preliminary results show that LLLT irradiation influences the in vitro proliferation of DPSCs and increases the expression of essential proteins for bone formation, although it is necessary to carry out further experiments on other cell types and to uniform the methodological designs.

[Charcot osteoarthropathy: don't miss it!]. / "Pied de Charcot": un diagnostic à ne pas manquer!

Charcot neuropathic osteoarthropathy (CNO) is a destructive process affecting the bone and joint structure of diabetic patients and resulting from peripheral neuropathy. It is a limb threatening condition resulting in dramatic deformities associated with severe morbi-mortality. The diagnosis is mostly made by the observation of inflammatory signs and higlight the importance of prompt foot evaluation. Imaging studies may help confirm the diagnosis and the severity of the condition but lack of specificity. The goal of the treatment is to maintain or achieve structural stability of the foot and ankle to prevent further deformity and plantar dislocation. The scientific evidences aren't strong enough to recommend bisphosphonates or acute surgical treatment. Surgery is unanimusly recommended to prevent secondary ulceration.

The differentiation of human adipose-derived stem cells (hASCs) into osteoblasts is promoted by low amplitude, high frequency vibration treatment.

Several studies have demonstrated that tissue culture conditions influence the differentiation of human adipose-derived stem cells (hASCs). Recently, studies performed on SAOS-2 and bone marrow stromal cells (BMSCs) have shown the effectiveness of high frequency vibration treatment on cell differentiation to osteoblasts. The aim of this study was to evaluate the effects of low amplitude, high frequency vibrations on the differentiation of hASCs toward bone tissue. In view of this goal, hASCs were cultured in proliferative or osteogenic media and stimulated daily at 30Hz for 45min for 28days. The state of calcification of the extracellular matrix was determined using the alizarin assay, while the expression of extracellular matrix and associated mRNA was determined by ELISA assays and quantitative RT-PCR (qRT-PCR). The results showed the osteogenic effect of high frequency vibration treatment in the early stages of hASC differentiation (after 14 and 21days). On the contrary, no additional significant differences were observed after 28days cell culture. Transmission Electron Microscopy (TEM) images performed on 21day samples showed evidence of structured collagen fibers in the treated samples. All together, these results demonstrate the effectiveness of high frequency vibration treatment on hASC differentiation toward osteoblasts.

[Metabolic syndrome, a mitochondrial disease?]. / Syndrome métabotique, une maladie mitochondriale?

The metabolic syndrome is a cluster of metabolic risk factors including: atherogenic dyslipidemia, elevated blood pressure, high plasma glucose and a prothrombotic and proinflammatory state, frequently associated to overweight. Impaired cell metabolism has been suggested as a relevant pathophysiological process. Indeed, the accumulation of intracellular fatty acylCoA and diacylglycerol, which then activate critical signal transduction pathways that ultimatly lead to suppression of insulin signalisation. Therefore a defect in mitochondrial function may be responsible for insulin resistance. Moreover, mitochondrial dysfunction has been found to take place in organs such as skeletal muscle, liver, pancreas and smoth vascular cells suggesting that mitochondrial defect could play a critical role in the occurence of cardiovascular diseases.

Upregulation of peroxisome proliferator-activated receptor gamma coactivator gene (PGC1A) during weight loss is related to insulin sensitivity but not to energy expenditure.

AIMS/HYPOTHESIS: We investigated whether skeletal muscle peroxisome proliferator-activated receptor gamma coactivator-1 (PGC1A; also known as PPARGC1A) and its target mitofusin-2 (MFN2), as well as carnitine palmitoyltransferase-1 (CPT1; also known as carnitine palmitoyltransferase 1A [liver] [CPT1A]) and uncoupling protein (UCP)3, are involved in the improvement of insulin resistance and/or in the modification of energy expenditure during surgically induced massive weight loss. MATERIALS AND METHODS: Seventeen morbidly obese women (mean BMI: 45.9 +/- 4 kg/m(2)) were investigated before, and 3 and 12 months after, Roux-en-Y gastric bypass (RYGB). We evaluated insulin sensitivity by the euglycaemic-hyperinsulinaemic clamp, energy expenditure and substrate oxidation by indirect calorimetry, and muscle mRNA expression by PCR. RESULTS: Post-operatively, PGC1A was enhanced at 3 (p = 0.02) and 12 months (p = 0.03) as was MFN2 (p = 0.008 and p = 0.03 at 3 and 12 months respectively), whereas UCP3 was reduced (p = 0.03) at 12 months. CPT1 did not change. The expression of PGC1A and MFN2 were strongly (p < 0.0001) related. Insulin sensitivity, which increased after surgery (p = 0.002 at 3, p = 0.003 at 12 months), was significantly related to PGC1A and MFN2, but only MFN2 showed an independent influence in a multiple regression analysis. Energy expenditure was reduced at 3 months post-operatively (p = 0.001 vs before RYGB), remaining unchanged thereafter until 12 months. CPT1 and UCP3 were not significantly related to the modifications of energy expenditure or of lipid oxidation rate. CONCLUSIONS/INTERPRETATION: Weight loss upregulates PGC1A, which in turn stimulates MFN2 expression. MFN2 expression significantly and independently contributes to the improvement of insulin sensitivity. UCP3 and CPT1 do not seem to influence energy expenditure after RYGB.

Transglutaminase 2 in the enterocytes is coeliac specific and gluten dependent.

BACKGROUND: Tissue transglutaminase, the coeliac autoantigen, was shown to localise in the enterocytes of coeliac patients and controls. It was speculated that surface tissue transglutaminase has a role in the pathogenesis of coeliac disease. AIMS: To study localisation of tissue transglutaminase in different stages of coeliac disease and other enteropathies with and without villous flattening. METHODS: Immunofluorescent and immunoblotting assays were used. Duodenal cryostat sections from 23 coeliac patients (10 untreated, 8 treated, 5 potential) and 18 controls (2 autoimmune enteropathy and 16 normal duodenal mucosa) were incubated with an anti-tissue transglutaminase monoclonal antibody. Slides were blindly examined. RESULTS: The immunofluorescent assay showed that monoclonal antibody localised in the subepithelial layer, in the lamina propria, and in the pericryptal connective tissue of all samples. It also bound to surface enterocytes in 8/10 untreated, 1/8 treated, and 3/5 potential coeliac patients. None of the controls showed an epithelial distribution of tissue transglutaminase. Immunoblotting experiments performed in enterocytes freshly isolated from duodenal biopsy confirmed these findings. CONCLUSION: Epithelial distribution of tissue transglutaminase is specific for coeliac disease rather than due to a non-specific mucosal inflammation. Analysis of different stages of coeliac disease suggests that the epithelial distribution of tissue transglutaminase is gluten dependent.

Altered expression of aquaporin 4 and H(+)/K(+)-ATPase in the stomachs of peptide YY (PYY) transgenic mice.

BACKGROUND INFORMATION: The hormone PYY (peptide YY), synthesized by endocrine cells in the pancreas, ileum, colon and stomach has widespread inhibitory effects on gastrointestinal and pancreatic fluid secretion. Transgenic mice expressing a viral oncoprotein under the control of the PYY gene 5'-flanking region develop well-differentiated colonic endocrine tumours producing mainly PYY and enteroglucagon. In the present study, we investigated the expression of AQP4 (aquaporin 4) water channel and H(+)/K(+)-ATPase in stomachs from both control and transgenic mice. RESULTS: Semi-quantitative RT (reverse transcriptase)-PCR showed an increase in the AQP4 transcript compared with control mice. Quantitative Western-blot analysis of stomachs from control and transgenic mice confirmed a significant increase in the 30 kDa AQP4 protein in transgenic mice. In control mice, AQP4 is specifically expressed in the basolateral membrane of gastric parietal cells, located in the basal region of the fundic glands. This particular location suggests that parietal cells in the base region of gastric pits might have a major role in water transport when compared with the more superficial parietal cells. Interestingly, immunofluorescence studies on transgenic mice revealed that the quantitative increase of AQP4 expression was actually due to an increase in the number of AQP4-expressing epithelial cells rather than to a higher expression of AQP4 in parietal cells. In fact, immunofluorescence experiments using the specific antibody raised against the AE2 isoform of Cl(-)/HCO3- exchanger specifically expressed in parietal cells confirmed that the number of parietal cells was comparable in both PYY and control stomachs. Moreover, in transgenic mice, a parallel significant decrease in the expression of H(+)/K(+)-ATPase was observed, as revealed by RT-PCR, quantitative immunoblotting and immunofluorescence. CONCLUSIONS: In the present study, we demonstrate that the sustained inhibition of gastric secretion due to tumours producing PYY/enteroglucagon in transgenic mice is associated with an increase in AQP4 expression and a down-regulation of H(+)/K(+)-ATPase in parietal cells that acquire the characteristics of basal parietal cells. The absence of H2 receptors-mediated signalling due to the inhibition of histamine release from ECL (enterochromaffin-like) cells by PYY may be in part responsible for the observed increase in the number of parietal cells expressing AQP4.

A creatine transporter is operative at the brush border level of the rat jejunal enterocyte.

Although ergogenic effects and health benefits have been reported for creatine used as nutritional supplement, to date little is known about the mechanism of creatine absorption in the small intestine. Thus the current study was undertaken to elucidate the mechanism of creatine intake in rat jejunum with the use of well-purified brush border membrane vesicles, isolated from jejunal enterocyte. Creatine uptake was found markedly stimulated by inwardly directed Na(+) and Cl(- )gradients, potential-sensitive, strongly reduced by the substitution of Na(+) and Cl(-) with various cations and anions and positively affected by intravesicular K(+). Moreover, creatine uptake is: 1) significantly inhibited by creatine structural analogs, 2) abolished by low concentrations of 2-aminoethyl methanethiosulfonate hydrobromide (MTSEA), 3) saturable as a function of creatine concentration with an apparent Michaelis-Menten constant of 24.08 +/- 0.80 muM and a maximal velocity of 391.30 +/- 6.19 pmoles mg protein(-1) 30 s(-1). The transport is electrogenic since at least two Na(+) and one Cl(-) are required to transport one creatine molecule. Western blot analysis showed the same amount of creatine transport protein in the jejunal apical membrane when compared to ileum. Thus, these data demonstrate the existence of a Na(+)- and Cl(-)-dependent, membrane potential-sensitive, electrogenic carrier-mediated mechanism for creatine absorption in rat jejunal apical membrane vesicles, which is biochemically and pharmacologically similar to those observed in other tissues. However, in other cell types the stimulatory effect of intravesicular K(+) was never detected.

Riboflavin phosphorylation is the crucial event in riboflavin transport by isolated rat enterocytes.

In isolated rat enterocytes, both normoenergized (normal) and de-energized with rotenone, riboflavin intracellular metabolic processes, operating in association with a membrane-specific transport mechanism, were investigated. The contents of unlabeled (endogenous) and labeled (exogenous) flavins [riboflavin (RF), flavin mononucleotide (FMN), flavin adenindinucleotide (FAD)] were determined by HPLC before and after incubation with tritiated RF. In normoenergized enterocytes, total labeled RF content (i.e., total uptake, the sum of RF membrane transport and intracellular metabolism) increased steadily to a plateau after 20 min incubation; FMN and FAD contents reached a plateau between 3 and 20 min, whereas free RF content increased constantly. The phosphorylated forms prevailed over the free form ( approximately 60% of total flavins). In de-energized enterocytes, RF total uptake was significantly lower than in normoenergized enterocytes and reached a plateau after only 3 min incubation. FMN and FAD contents were significantly lower than in normoenergized enterocytes, and free RF represented the prevailing form of flavins (70% of total RF ). In both normoenergized and de-energized enterocytes, the contents of unlabeled total RF, FMN and FAD decreased significantly after 20 min incubation, whereas free RF increased significantly only in normoenergized enterocytes. After 20 min incubation, the RF structural analog 8-dimethyl-amino-8-demethyl-RF caused a significant decrease of all flavin contents, whereas 5'-deoxy-RF decreased only the total and free RF contents. Results directly confirmed the leading role of metabolic processes such as phosphorylation in RF transport by isolated small intestinal enterocytes.