The Natural Sweetener Stevia: An Updated Review on its Phytochemistry, Health Benefits, and Anti-diabetic Study.

Stevia rebaudiana Bertoni is one of the significant high qualities of non-caloric sugar substitute sweetener plants against diabetes disease. Diabetes mellitus is one of the most common metabolic diseases caused by insulin secretion defects, insulin resistance in peripheral tissues, or both. Stevia rebaudiana is a perennial shrub of the Compositae family that is grown in several places around the world. It contains a plethora of different bioactive constituents which are responsible for several activities and sweetness. This sweetness is due to the presence of steviol glycosides which is 100-300 times sweeter than sucrose. Furthermore, stevia reduces oxidative stress, lowering the risk of diabetes. Its leaves have been used to control and treat diabetes and a variety of other metabolic diseases. This review summarizes the history, bioactive constituents of S. rebaudiana extract, pharmacology, anti-diabetic activity, and its application, especially in food supplements.

The dietary sweetener sucralose is a negative modulator of T cell-mediated responses.

Artificial sweeteners are used as calorie-free sugar substitutes in many food products and their consumption has increased substantially over the past years1. Although generally regarded as safe, some concerns have been raised about the long-term safety of the consumption of certain sweeteners2-5. In this study, we show that the intake of high doses of sucralose in mice results in immunomodulatory effects by limiting T cell proliferation and T cell differentiation. Mechanistically, sucralose affects the membrane order of T cells, accompanied by a reduced efficiency of T cell receptor signalling and intracellular calcium mobilization. Mice given sucralose show decreased CD8+ T cell antigen-specific responses in subcutaneous cancer models and bacterial infection models, and reduced T cell function in models of T cell-mediated autoimmunity. Overall, these findings suggest that a high intake of sucralose can dampen T cell-mediated responses, an effect that could be used in therapy to mitigate T cell-dependent autoimmune disorders.

Preferences of Sjögren's syndrome patients regarding potential new saliva substitutes.

OBJECTIVES: Sjögren's syndrome (SS) patients should be involved in the development of new saliva substitutes at an early stage. The purpose of the current study was to explore the preferences of these patients regarding various product characteristics of potential new saliva substitutes. MATERIAL AND METHOD: A questionnaire was distributed among SS patients. They could anonymously indicate their preferences for saliva substitute characteristics using 5-point Likert scales. RESULTS: Fifty-nine SS patients filled in the questionnaire. According to their opinion, the most ideal saliva substitute has a thin-watery consistency with a neutral flavour that should be applied as a spray. Patients demand a prolonged alleviation of dry mouth complaints and neutralization of harmful bacteria. The patients mainly object against the presence of artificial sweeteners and alcohol in saliva substitutes, but have limited objections against the presence of vegetable-based ingredients and natural enzymes. Major objections were against the potential side effects "bitter taste" and "discoloration of teeth". Age and severity of xerostomia affected desire of flavours. Younger patients preferred menthol flavour, while respondents with severe xerostomia preferred the use of "neutral flavours" significantly more. CONCLUSION: The most ideal saliva substitute has thin-watery consistency in spray form with a neutral flavour and providing long alleviation of dry mouth complaints. Besides, it should not contain artificial sweeteners or alcohol, and should not have a bitter taste or cause discoloration of the teeth. CLINICAL RELEVANCE: Investigating the opinion of SS patients provides tailoured insights into their preference, which may contribute to the development of more effective saliva substitutes.

The complex relationship between metabolic syndrome and sweeteners.

Metabolic syndrome is a multifactorial disorder originating from central obesity through a high caloric intake and a sedentary lifestyle. Metabolic syndrome increases the risk of type 2 diabetes (T2D) disease, converting it to one of the costliest chronic diseases, which reduces life quality. A strategy proposed by the food industry to reduce this problem is the generation of low-caloric products using sweeteners, which are compounds that can substitute sucrose, given their sweet taste. For many years, it was assumed that sweeteners did not have a relevant interaction in metabolism. However, recent studies have demonstrated that sweeteners interact either with metabolism or with gut microbiota, in which sweet-taste receptors play an essential role. This review presents an overview of the industrial application of most commonly consumed sweeteners. In addition, the interaction of sweeteners within the body, including their absorption, distribution, metabolism, gut microbiota metabolism, and excretion is also reviewed. Furthermore, the complex relationship between metabolic syndrome and sweeteners is also discussed, presenting results from in vivo and clinical trials. Findings from this review indicate that, in order to formulate sugar-free or noncaloric food products for the metabolic syndrome market, several factors need to be considered, including the dose, proportions, human metabolism, and interaction of sweeteners with gut microbiota and sweet-taste receptors. More clinical studies, including the metabolic syndrome, are needed to better understand the interaction of sweeteners with the human body, as well as their possible effect on the generation of dysbiosis.

A Graded Approach to Intravenous Dextrose for Neonatal Hypoglycemia Decreases Blood Glucose Variability, Time in the Neonatal Intensive Care Unit, and Cost of Stay.

OBJECTIVE: To determine associations between a graded approach to intravenous (IV) dextrose treatment for neonatal hypoglycemia and changes in blood glucose (BG), length of stay (LOS), and cost of care. STUDY DESIGN: Retrospective cohort study of 277 infants born at ≥35 weeks of gestation in an urban academic delivery hospital, comparing the change in BG after IV dextrose initiation, neonatal intensive care unit (NICU) LOS, and cost of care in epochs before and after a hospital protocol change. During epoch 1, all infants who needed IV dextrose for hypoglycemia were given a bolus and started on IV dextrose at 60 mL/kg/day. During epoch 2, infants received IV dextrose at 30 or 60 mL/kg/day based on the degree of hypoglycemia. Differences in BG outcomes, LOS, and cost of hospital care between epochs were compared using adjusted median regression. RESULTS: In epoch 2, the median (IQR) rise in BG after initiating IV dextrose (19 [10, 31] mg/dL) was significantly lower than in epoch 1 (24 [14,37] mg/dL; adjusted ß = -6.0 mg/dL, 95% CI -11.2, -0.8). Time to normoglycemia did not differ significantly between epochs. NICU days decreased from a median (IQR) of 4.5 (2.1, 11.0) to 3.0 (1.5, 6.5) (adjusted ß = -1.9, 95% CI -3.0, -0.7). Costs associated with NICU hospitalization decreased from a median (IQR) $14 030 ($5847, $30 753) to $8470 ($5650, $19 019) (adjusted ß = -$4417, 95% CI -$571, -$8263) after guideline implementation. CONCLUSIONS: A graded approach to IV dextrose was associated with decreased BG lability and length and cost of NICU stay for infants with neonatal hypoglycemia.

The Crashing Toxicology Patient.

This article examines, using an organ-systems based approach, rapid diagnosis, resuscitation, and critical care management of the crashing poisoned patient in the emergency department. The topics discussed in this article include seizures and status epilepticus, respiratory failure, cardiovascular collapse and mechanical circulatory support, antidotes and drug-specific therapies, acute liver failure, and extracorporeal toxin removal.

Contribution of Katsura-uri (Japan's Heirloom Pickling Melon, Cucumis melo var. conomon) at the Completely Ripe Stage to Diabetes Control.

The fruit of Katsura-uri (Japan's heirloom pickling melon, Cucumis melo var. conomon) possesses a fruity aroma and moderate sweetness. The fruit juice has potential to minimize human postprandial blood glucose levels. This study provides information regarding the health benefits of Katsura-uri and its utility in treating diabetes. The study methodology involved measuring the color and firmness of Katsura-uri fruit at five ripening stages, and quantitation of the aroma substances, proximate composition, and sugars. Significant changes were detected in the color, firmness, and level of aroma substances with ripening of Katsura-uri fruit, albeit with no major changes in proximate composition, with the exception of dietary fiber, and sugars. To determine the effects of Katsura-uri juice, the blood glucose levels of ten diabetic volunteers aged 46-75 y were monitored after its consumption, and compared with after consumption of muskmelon juice equivalent to the total weight of Katsura-uri juice. The blood glucose area under the curve level was significantly lower after consumption of Katsura-uri juice (16±5 h • mg/dL) than after consumption of muskmelon juice (55±17 h • mg/dL; p<0.05). The level of the glucose spike was also significantly lower after consumption of Katsura-uri juice (22±5 mg/dL) than after consumption of muskmelon juice (64±6 mg/dL; p<0.05). The completely ripe Katsura-uri fruit provides the best results for diabetic subjects, which is the first case of fruits sweetened with the addition of zero-calorie sweeteners.

Effects of short-term xylitol chewing gum on pro-inflammatory cytokines and Streptococcus mutans: A randomised, placebo-controlled trial.

INTRODUCTION: Dental caries is an infectious disease with predominantly of cariogenic bacteria such as Streptococcus mutans (S mutans). Xylitol is considered as one of the effective agents that can limit this dental infection. In this randomised, placebo-controlled trial, we aimed to evaluate the potential reflection of short-term xylitol consumption on pro-inflammatory cytokines (TNF-α, IL-6 and IL-8) and S mutans counts by ELISA and qPCR (Quantitative real-time PCR), respectively. METHODS: In this study, 154 participants were assigned to two groups, control and xylitol. Dental examination, saliva and swab samples were done at baseline and at 3-week for clinical and microbiological assessment. RESULTS: In xylitol group at the end of 3-week, gingival and plaque index scores were significantly decreased with respect to baseline values (P < .001 and P < .05, respectively). The salivary concentration of TNF-α, IL-6 and IL-8 were statistically declined at 3-week, more so than those at baseline in xylitol group (P < .001). S mutans expression was reduced about fivefold at 3-week use of xylitol and it was a statistically significant difference compared to baseline (P < .001). CONCLUSION: Intriguingly, even short-term consumption of xylitol might play a favourable role in maintaining the oral health status, possibly as a result of decreasing the release of pro-inflammatory cytokines and the counts of S mutans. Nonetheless, this investigation warrants further endorsement.

Therapeutic challenges in the management of osmotic demyelination syndrome: A case report of a favorable outcome from a tertiary center.

RATIONALE: There is an increasing and compelling need for early recognition of features of osmotic demyelination syndrome (ODS), and a further attempt at correcting this even where presentation is late. PATIENT CONCERNS: A 49-year-old male admitted into the emergency department with a complaint of lethargy and severe hyponatremia, with subsequent ODS supervening on initial attempts at correction. DIAGNOSIS: Rapid rise in serum sodium concentration (121 mmol/L in 8 hours from a nadir of 101 mmol/L), concomitant deterioration in patient's conscious level support the diagnosis of ODS. INTERVENTION: Concomitant administration of 5% dextrose water with desmopressin with a therapeutic objective of gradual relowering of serum sodium concentration. OUTCOMES: Significant improvement in patients' conscious level and motor function with the commencement of sodium relowering therapy. The patient was eventually discharged home. LESSONS: Regardless of the temporal profile of neurologic sequelae following ODS due to hyponatremia, its worthwhile attempting initial sodium relowering with dextrose 5% and desmopressin and then monitoring of biochemical and neurologic markers.

Changes in the Level of DNA Fragmentation in Sperm Cells detected by Acridine Orange Test in Men with Sub/infertility Treated with Nutritional Supplement PAPA.

BACKGROUND: When diagnosing and treating male infertility it is important to determine whether there are defects in the maturation process of sperm nuclei. Using nutritional supplements can improve the morphological and physiological condition of the spermatozoa. In recent years there has been an increase in the usage of supplements with different compositions which strives to determine the best combination and avoid side effects. AIM: To study the effect of PAPA nutritional supplement on the levels of DNA fragmentation of sperm cells tested with acridine orange test (single stranded DNA against double stranded DNA) in men with sub/infertility. MATERIALS AND METHODS: 48 men with confirmed sub/infertility underwent treatment for three months with nutritional supplement PAPA containing 9 micronutrients. The differences in levels of DNA fragmentation were determined with acridine orange test, which was conducted before and after the treatment. RESULTS: The results were statistically significant (p<0.001) showing an increase in the number of green spermatozoa (normal DNA), and a decrease of damaged ones (orange and red). After treatment the level of sperm DNA fragmentation decreased by 10.2%. CONCLUSION: Men with confirmed sub/infertility that took nutritional supplement PAPA for three moths showed a decrease in DNA fragmentation levels of 10.2% determined by AO test which implies an improvement of male fertility levels.

The protective effects of Mogroside V and its metabolite 11-oxo-mogrol of intestinal microbiota against MK801-induced neuronal damages.

RATIONALE: Animal models, notably with non-competitive NMDA receptor antagonist MK801, are commonly used to investigate the mechanisms of schizophrenia and to pursue its mechanism-related drug discoveries. OBJECTIVES: In the current study, we have extensively examined the protective effects of MogrosideV (MogV), a plant-derived three terpene glucoside known to exhibit anti-oxidative and anti-inflammatory activities. METHODS AND RESULTS: Here, we investigated its protective effects against neuronal damages elicited by MK-801 treatment. Our behavioral experimental results showed that MK-801-induced PPI deficits and social withdrawal were prevented by MogV treatment. Moreover, the cellular and neurochemical responses of MK-801 in medial prefrontal cortical cortex (mPFC) were also ameliorated by MogV treatment. Also, profiling metabolites assay through artificial intestinal microbiota was performed to identify bioactive components of MogV. An in vitro study of primary neuronal culture demonstrated that MogV and its metabolite 11-oxo-mogrol treatment prevented the MK-801-induced neuronal damages through the mechanisms of promoting neurite outgrowth, inhibiting cell apoptosis, and [Ca2+]i release. Additionally, 11-oxo-mogrol reversed inactivation of phosphorylation levels of AKT and mTOR induced by MK801. CONCLUSIONS: These results suggest therapeutic potential of MogV for schizophrenia.

Nonpharmacologic Management of Pain During Common Needle Puncture Procedures in Infants: Current Research Evidence and Practical Considerations: An Update.

Infants undergo painful procedures involving skin puncture as part of routine medical care. Pain from needle puncture procedures is suboptimally managed. Numerous nonpharmacologic interventions are available that may be used for these painful procedures, including swaddling/containment, pacifier/non-nutritive sucking, rocking/holding, breastfeeding and breastmilk, skin-to-skin care, sweet tasting solutions, music therapy, sensorial saturation, and parental presence. Adoption these interventions into routine clinical practice is feasible and should be a standard of care in quality health care for infants. This review summarizes the epidemiology of pain from common needle puncture procedures in infants, the effectiveness of nonpharmacologic interventions, implementation considerations, and unanswered questions.

Stevia rebaudiana Bertoni bioactive effects: From in vivo to clinical trials towards future therapeutic approaches.

Stevia rebaudiana Bertoni, a plant from South America and indigenous of Paraguay, has shown several biological effects and healthy properties, although it is especially used in South America and some Asiatic regions. In addition, it is a natural sweetener, almost 300 times sweeter than sucrose, being attributed to its phytoconstituents prominent antioxidant, antimicrobial, antidiabetic (antihyperglycemic, insulinotropic, and glucagonostatic), antiplatelet, anticariogenic, and antitumor effects. In this sense, this work aims to provide an extensive overview on the historical practices of stevia and its effects in human health based on its chemical composition and applications for both food and pharmaceutical industries.

Hedonic drinking engages a supraspinal inhibition of thermal nociception in adult rats.

The taste of sucrose is commonly used to provide pain relief in newborn humans and is innately analgesic to neonatal rodents. In adulthood, sucrose remains a strong motivator to feed, even in potentially hazardous circumstances (ie, threat of tissue damage). However, the neurobiological mechanisms of this endogenous reward-pain interaction are unclear. We have developed a simple model of sucrose drinking-induced analgesia in Sprague-Dawley rats (6-10 weeks old) and have undertaken a behavioral and pharmacological characterization using the Hargreaves' test of hind-paw thermal sensitivity. Our results reveal an acute, potent, and robust inhibitory effect of sucrose drinking on thermal nociceptive behaviour that unlike the phenomenon in neonates is independent of endogenous opioid signalling and does not seem to operate through classical descending inhibition of the spinal cord circuitry. Experience of sucrose drinking had a conditioning effect whereby the apparent expectancy of sucrose enabled water alone (in euvolemic animals) to elicit a short-lasting placebo-like analgesia. Sweet taste alone, however, was insufficient to elicit analgesia in adult rats intraorally perfused with sucrose. Instead, the sucrose analgesia phenomenon only appeared after conditioning by oral perfusion in chronically cannulated animals. This sucrose analgesia was completely prevented by systemic dosing of the endocannabinoid CB1 receptor antagonist rimonabant. These results indicate the presence of an endogenous supraspinal analgesic circuit that is recruited by the context of rewarding drinking and is dependent on endocannabinoid signalling. We propose that this hedonic sucrose-drinking model may be useful for further investigation of the supraspinal control of pain by appetite and reward.

Biofunctionalization of magnetite nanoparticles with stevioside: effect on the size and thermal behaviour for use in hyperthermia applications.

Controlling the magnetic properties of a nanoparticle efficiently via its particle size to achieve optimized heat under alternating magnetic field is the central point for magnetic hyperthermia-mediated cancer therapy (MHCT). Here, we have shown the successful use of stevioside (a natural plant-based glycoside) as a promising biosurfactant to control the magnetic properties of Fe3O4 nanoparticles by controlling the particle size. The biocompatibility and cellular uptake efficiency by rat C6 glioma cells and calorimetric magnetic hyperthermia profile of the nanoparticles were further examined. Our finding suggests superior properties of stevioside-coated magnetite nanoparticles in comparison to polysorbate-80 and oleic acid coated nanomagnets as far as particle size reduction, biocompatibility, hyperthermic effect, and cellular uptake by the glioblastoma cancer cells are concerned. The stevioside-coated nanomagnets exhibiting the maximum temperature rise were further investigated as heating agents in in vitro magnetic hyperthermia experiments (405 kHz, 168 Oe), showing their efficacy to induce cell death of rat C6 glioma cells after 30 min at a target temperature T = 43 °C.

Influence of Glucose Dosage in Parenteral Nutrition on Body Thiamine Levels in Rats.

The objective of this study was to determine the relationship between glucose dosage in parenteral nutrition and reductions in levels of body thiamine in rats. Vitamin-free infusions with differing amounts of glucose were administered to normal or thiamine-deficient rats for 5 days, after which urinary thiamine excretion and the amounts of thiamine in the blood, liver, brain, and skeletal muscles were measured. The total energy dosage was set at three levels (98, 140, and 196 kcal/kg), and the dose of amino acids was constant among all groups. Urinary thiamine excretions on Day 5 decreased with increasing glucose dosage in the infusions. In normal rats, the amount of thiamine in the blood and all organs decreased compared with the diet group; however, no significant differences were found among the infusion groups. In thiamine-deficient rats, on the other hand, the amount of thiamine in the liver and skeletal muscles did not differ significantly among infusion groups; however, the amount of thiamine in the brain and blood decreased with increasing glucose dosage. An organ-specific correlation was found between glucose dosage in infusions and reductions in levels of thiamine. To prevent thiamine deficiencies from affecting the central nervous system, greater caution must be exercised during high-caloric parenteral nutrition. However, a constant supply of thiamine seemed to be essential, irrespective of the amount of energy supplied via parenteral nutrition, to maintain a sufficient level of thiamine in the body.

Outcomes and emergency medical services resource utilization among patients with syncope arriving to the emergency department by ambulance.

OBJECTIVE: Syncope accounts for 1% of emergency department (ED) visits, yet few experience a serious adverse event (SAE). Two-thirds of syncope patients are transported to the ED by ambulance, placing considerable burden on emergency medical services (EMS), and many of these transports may be unnecessary. We estimated the proportion of syncope patients who fell into a low-risk category based on an ED diagnosis of vasovagal syncope and the absence of EMS intervention, hospitalization, or SAE. METHODS: We conducted a multicentre prospective cohort study enrolling adult syncope patients transported to the ED by ambulance over 13 months. We collected demographics and EMS interventions, and followed patients for 30 days to identify all SAE, including death, dysrhythmia, myocardial infarction, aortic dissection, pulmonary embolism, subarachnoid hemorrhage, significant hemorrhage, and related procedural interventions. RESULTS: Of 990 (67.2%) patients transported to the ED by ambulance, 121 had EMS interventions, 137 suffered 30-day SAE, 393 (39.7%; 95%CI 36.6, 42.8) were deemed low risk, 41 patients with vasovagal syncope were lost to follow-up, and 298 patients were diagnosed with non-vasovagal syncope. During transport, 121 (12.2%; 95%CI 10.2, 14.3) patients underwent some EMS intervention, and 137 (14.6%; 95%CI 12.4, 16.9) suffered SAEs within 30 days. CONCLUSION: About 40% of patients transported to the ED by ambulance are at low risk and may not benefit from paramedic care or transport to a hospital. A robust clinical decision tool would help identify patients safe for treat-and-release, diversion to alternative care, or rapid offload into low-acuity ED areas, potentially reducing EMS workload and cost.

OBJECTIF: Les syncopes motivent 1 % des consultations au service des urgences (SU), mais le malaise entraîne peu d'événements indésirables graves (EIG). Ainsi, deux tiers des patients ayant subi une syncope sont transportés en ambulance au SU, ce qui impose un lourd fardeau sur les services médicaux d'urgence (SMU), et pourtant bon nombre de transports effectués seraient non nécessaires. Aussi l'étude visait-elle à estimer la proportion de patients ayant subi une syncope dont l'état serait jugé à faible risque d'après le diagnostic de syncope vasovagale posé au SU ainsi que d'après l'absence d'intervention faite par les SMU, d'hospitalisation ou d'EIG. MÉTHODE: Il s'agit d'une étude prospective de cohortes, multicentrique, menée chez des adultes qui ont subi une syncope et qui ont été transportés en ambulance au SU, sur une période de 13 mois. Ont été recueillies des données démographiques ainsi que les notes sur les interventions effectuées par les SMU; à cela s'ajoute un suivi de 30 jours aux fins de collecte de renseignements sur tout EIG : mort, arythmie, infarctus du myocarde, dissection de l'aorte, embolie pulmonaire, hémorragie sous-arachnoïdienne, hémorragie importante et gestes interventionnels liés aux troubles en question. RÉSULTATS: Au total, 990 patients (67,2 %) ont été transportés en ambulance au SU; sur ce nombre, 121 ont subi des interventions pratiquées par les SMU; 137 ont connu un EIG au cours des 30 jours suivant le malaise; 393 (39,7 %; IC à 95 % : 36,6-42,8) ont été jugés à faible risque; 41 ayant fait une syncope vasovagale ont été perdus de vue durant le suivi; et 298, ont fait une syncope non vasovagale. Durant le transport, 121 patients (12,2 %; IC à 95 % : 10,2-14,3) ont subi une forme quelconque d'intervention par les SMU et, au cours des 30 jours de suivi, 137 (14,6 %; IC à 95 % : 12,4-16,9) ont connu un EIG. CONCLUSION: Environ 40 % des patients transportés en ambulance au SU connaissent un faible risque et, dans leur cas, la prestation de soins paramédicaux ou le transport à l'hôpital pourraient ne pas être nécessaires. Un outil d'aide à la décision clinique qui soit digne de confiance pourrait faciliter le repérage des patients dont l'état se prêterait au traitement suivi du congé, à une orientation vers d'autres types de soins ou à un passage rapide dans des zones de petites urgences, ce qui permettrait à la fois de réduire la charge de travail des SMU ainsi que les coûts.

Inadvertent iatrogenic insulin detemir 1000 units overdose in a hospitalised patient.

A 69-year-old woman with uncontrolled type 2 diabetes mellitus was admitted in the hospital for the management of urosepsis. Patient was overdosed with detemir insulin 1000 units inadvertently. Care provider was confused with volume and dose of the insulin by using insulin vial. Blood sugars were monitored closely every 30 min-1 hour for 24 hours. Patient was treated with dextrose 5% and 10% continuous infusion; and hydrocortisone 75 mg every 6 hours for 24 hours. The lowest blood sugar reached was 142 mg/dL (7.9 mmo/L). Patient did not develop hypoglycaemia. Proper safety measures and mandatory nurse education about administration of insulin were implemented to prevent future occurrences.

Valoración de la inhibición del crecimiento de los estreptococcus mutans a partir de la utilización de edulcorantes y probióticos: Estudio in vitro

En nuestro país la caries se manifiesta como enfermedad endémica, muy destructiva y de alta prevalencia. Cada día se pueden encontrar más productos en el mercado que presentan en su composición sustitutos de sacarosa, como el xilitol. Asimismo, la incorporación a la dieta de probióticos puede beneficiar la salud bucal previniendo el crecimiento de la biopelícula dental, pueden competir por los sitios de unión e inhibir la adherencia de Streptococcus mutans, así como también producir sustancias antibacterianas contra los mismos. El desarrollo de esta investigación planteó revelar cuál es el grado de inhibición de crecimiento bacteriano de Streptococcus mutans ante soluciones como el xilitol, probióticos y la asociación xilitol ­ probiótico