Effect of Black Tea Consumption on Urinary Risk Factors for Kidney Stone Formation.

Copious fluid intake is the most essential nutritional measure in the treatment of urolithiasis, and is suggested to be a protective factor in the primary prevention of urinary stone formation. Although the intake of black tea contributes to daily fluid intake, the high oxalate content could outweigh the beneficial effect of urine dilution. The present study investigated the effect of black tea consumption on urinary risk factors for kidney stone formation. Ten healthy men received a standardized diet for a period of ten days. Subjects consumed 1.5 L/day of fruit tea (0 mg/day oxalate) during the 5-day control phase, which was replaced by 1.5 L/day of black tea (86 mg/day oxalate) during the 5-day test phase. Fractional and 24-h urines were obtained. The intake of black tea did not significantly alter 24-h urinary oxalate excretion. Urinary citrate, an important inhibitor of calcium stone formation, increased significantly, while the relative supersaturation of calcium oxalate, uric acid, and struvite remained unchanged. No significantly increased risk for kidney stone formation could be derived from the ingestion of black tea in normal subjects. Further research is needed to evaluate the impact of black tea consumption in kidney stone patients with intestinal hyperabsorption of oxalate.

Dietary Oxalate Loading Impacts Monocyte Metabolism and Inflammatory Signaling in Humans.

Diet has been associated with several metabolic diseases and may impact immunity. Increased consumption of meals with high oxalate content may stimulate urinary calcium oxalate (CaOx) crystals, which are precursors to CaOx kidney stones. We previously reported that CaOx stone formers have decreased monocyte cellular bioenergetics compared to healthy participants and oxalate reduces monocyte metabolism and redox status in vitro. The purpose of this study was to investigate whether dietary oxalate loading impacts monocyte cellular bioenergetics, mitochondrial complex activity, and inflammatory signaling in humans. Healthy participants (n = 40; 31.1 ± 1.3 years) with a BMI of 24.9 ± 0.6 kg/m2 consumed a controlled low oxalate diet for 3 days before drinking a blended preparation of fruits and vegetables containing a large amount of oxalate. Blood and urine were collected before (pre-oxalate) and for 5 h after the oxalate load to assess urinary oxalate levels, monocyte cellular bioenergetics and mitochondrial complex activity, and plasma cytokine/chemokine levels. Urinary oxalate levels significantly increased in post-oxalate samples compared to pre-oxalate samples. Monocyte cellular bioenergetics, mitochondrial complex I activity, and plasma cytokine and chemokine levels were altered to varying degrees within the study cohort. We demonstrate for the first time that dietary oxalate loading may impact monocyte metabolism and immune response in a cohort of healthy adults, but these response are variable. Further studies are warranted to understand oxalate mediated mechanisms on circulating monocytes and how this potentially influences CaOx kidney stone formation. Clinical Trial Registration: ClinicalTrials.gov, identifier NCT03877276.

Impact of Phyllantus niruri and Lactobacillus amylovorus SGL 14 in a mouse model of dietary hyperoxaluria.

Hyperoxaluria is a pathological condition which affects long-term health of kidneys. The present study evaluates the impact of the combination of Lactobacillus amylovorus SGL 14 and the plant extract Phyllantus niruri (namely Phyllantin 14™) on dietary hyperoxaluria. Safety and efficacy of Phyllantin 14 have been evaluated in vivo. Mice C57BL6 fed a high-oxalate diet were compared to mice fed the same diet administered with Phyllantin 14 by gavage for 6 weeks. Control mice were fed a standard diet without oxalate. No adverse effects were associated to Phyllantin 14 supplementation, supporting its safety. Mice fed a high-oxalate diet developed significant hyperoxaluria and those administered with Phyllantin 14 showed a reduced level of urinary oxalate and a lower oxalate-to-creatinine ratio. Soluble and insoluble caecal oxalate were significantly lower in treated group, a finding in agreement with the colonisation study, i.e. mice were colonised with SGL 14 after 3 weeks. Microbiota analysis demonstrated that both oxalate diet and Phyllantin 14 can differently modulate the microbiota. In conclusion, our findings suggest that Phyllantin 14 supplementation represents a potential supportive approach for reducing urinary oxalate and/or for enhancing the efficacy of existing treatments.

Is There Such a Thing as "Anti-Nutrients"? A Narrative Review of Perceived Problematic Plant Compounds.

Plant-based diets are associated with reduced risk of lifestyle-induced chronic diseases. The thousands of phytochemicals they contain are implicated in cellular-based mechanisms to promote antioxidant defense and reduce inflammation. While recommendations encourage the intake of fruits and vegetables, most people fall short of their target daily intake. Despite the need to increase plant-food consumption, there have been some concerns raised about whether they are beneficial because of the various 'anti-nutrient' compounds they contain. Some of these anti-nutrients that have been called into question included lectins, oxalates, goitrogens, phytoestrogens, phytates, and tannins. As a result, there may be select individuals with specific health conditions who elect to decrease their plant food intake despite potential benefits. The purpose of this narrative review is to examine the science of these 'anti-nutrients' and weigh the evidence of whether these compounds pose an actual health threat.

Metabolic profile and impact of diet in patients with primary hyperoxaluria.

PURPOSE: The primary goal of this pilot study was to evaluate metabolic characteristics and to examine the impact of diet in patients with primary hyperoxaluria (PH) under controlled, standardized conditions. METHODS: Four patients with genetically confirmed PH collected 24 h urines on their habitual, self-selected diets and on day 1, 6, 7, 8, and 11 under controlled, standardized conditions. The [13C2]oxalate absorption, calcium, and ammonium chloride loading tests were performed. RESULTS: While none of the patients had abnormal findings from the calcium loading test, incomplete distal renal tubular acidosis (RTA) was diagnosed in each of the four patients. Dietary intervention resulted in a significant decrease in urinary oxalate expressed as molar creatinine ratio (mmol/mol) between 30 and 40% in two of four patients. The evaluation of dietary records revealed a high daily intake of oxalate-rich foods as well as gelatin-containing sweets and meat products, rich sources of hydroxyproline, under the habitual, self-selected diets of the two responders. Intestinal oxalate hyperabsorption of 12.4% in one of the two patients may have additionally contributed to the increased urinary oxalate excretion under the individual diet. CONCLUSIONS: Our pilot data indicate that patients with PH may benefit from a restriction of dietary oxalate and hydroxyproline intake. Further research is needed to define the role of distal RTA in PH and to evaluate the hypothesis of an acquired acidification defect.

Nutrients Turned into Toxins: Microbiota Modulation of Nutrient Properties in Chronic Kidney Disease.

In chronic kidney disease (CKD), accumulation of uremic toxins is associated with an increased risk of death. Some uremic toxins are ingested with the diet, such as phosphate and star fruit-derived caramboxin. Others result from nutrient processing by gut microbiota, yielding precursors of uremic toxins or uremic toxins themselves. These nutrients include l-carnitine, choline/phosphatidylcholine, tryptophan and tyrosine, which are also sold over-the-counter as nutritional supplements. Physicians and patients alike should be aware that, in CKD patients, the use of these supplements may lead to potentially toxic effects. Unfortunately, most patients with CKD are not aware of their condition. Some of the dietary components may modify the gut microbiota, increasing the number of bacteria that process them to yield uremic toxins, such as trimethylamine N-Oxide (TMAO), p-cresyl sulfate, indoxyl sulfate and indole-3 acetic acid. Circulating levels of nutrient-derived uremic toxins are associated to increased risk of death and cardiovascular disease and there is evidence that this association may be causal. Future developments may include maneuvers to modify gut processing or absorption of these nutrients or derivatives to improve CKD patient outcomes.

Effect of Dietary Oxalate on the Gut Microbiota of the Mammalian Herbivore Neotoma albigula.

Diet is one of the primary drivers that sculpts the form and function of the mammalian gut microbiota. However, the enormous taxonomic and metabolic diversity held within the gut microbiota makes it difficult to isolate specific diet-microbe interactions. The objective of the current study was to elucidate interactions between the gut microbiota of the mammalian herbivore Neotoma albigula and dietary oxalate, a plant secondary compound (PSC) degraded exclusively by the gut microbiota. We quantified oxalate degradation in N. albigula fed increasing amounts of oxalate over time and tracked the response of the fecal microbiota using high-throughput sequencing. The amount of oxalate degraded in vivo was linearly correlated with the amount of oxalate consumed. The addition of dietary oxalate was found to impact microbial species diversity by increasing the representation of certain taxa, some of which are known to be capable of degrading oxalate (e.g., Oxalobacter spp.). Furthermore, the relative abundances of 117 operational taxonomic units (OTU) exhibited a significant correlation with oxalate consumption. The results of this study indicate that dietary oxalate induces complex interactions within the gut microbiota that include an increase in the relative abundance of a community of bacteria that may contribute either directly or indirectly to oxalate degradation in mammalian herbivores.

[Oxalate: a poorly soluble organic waste with consequences]. / L'oxalate: un déchet organique peu soluble, avec conséquences.

Oxalate is a highly insoluble metabolic waste excreted by the kidneys. Disturbances of oxalate metabolism are encountered in enteric hyperoxaluria (secondary to malabsorption, gastric bypass or in case of insufficient Oxalobacter colonization), in hereditary hyperoxaluria and in intoxication (ethylene glycol, vitamin C). Hyperoxaluria causes a large spectrum of diseases, from isolated hyperoxaluria to kidney stones and nephrocalcinosis formation, eventually leading to kidney failure and systemic oxalosis with life-threatening deposits in vital organs. New causes of hyperoxaluria are arising recently, in particular after gastric bypass surgery, which requires regular and preemptive monitoring. The treatment of hyperoxaluria involves reduction in oxalate intake and increase in calcium intake. Optimal urine dilution and supplementation with inhibitors of kidney stone formation (citrate) are required. Some conditions may need vitamin B6 supplementation, and the addition of probiotics might be useful in the future. Primary care physicians should identify cases of recurrent calcium oxalate stones and severe hyperoxaluria. Further management of hyperoxaluria requires specialized care.

L'oxalate est un déchet métabolique peu soluble excrété par les reins, et les hyperoxaluries peuvent être distinguées en hyperoxaluries entériques, hyperoxaluries héréditaires et les intoxications (éthylène glycol, vitamine C). L'hyperoxalurie induit un large spectre de maladies allant de l'hyperoxalurie isolée, formation de calculs rénaux, voire d'une néphrocalcinose, à l'insuffisance rénale et l'oxalose systémique avec des dépôts s'accumulant dans de nombreux organes. De nouvelles causes d'hyperoxalurie sont apparues ces dernières années, en particulier les hyperoxaluries survenant à la suite d'un bypass gastrique. Le traitement des hyperoxaluries fait intervenir, d'une part, une diminution contrôlée des apports en oxalate et une augmentation des apports en calcium et, d'autre part, une dilution des urines et l'ajout d'inhibiteurs de la lithogenèse (citrate). Dans certaines conditions particulières, une supplémentation en vitamine B6 ou l'utilisation de probiotiques peuvent être envisagées. Le praticien doit rester attentif aux cas de calculs d'oxalate de calcium récidivants ou d'hyperoxalurie sévère et les adresser pour une prise en charge spécialisée et multidisciplinaire.

Fish oil supplementation and urinary oxalate excretion in normal subjects on a low-oxalate diet.

OBJECTIVE: To determine if fish oil supplementation reduces endogenous oxalate synthesis in healthy subjects. MATERIALS AND METHODS: Fifteen healthy non-stone-forming adults participated in this study. Subjects first abstained from using vitamins, medications, or foods enriched in omega-3 fatty acids for 30 days. Next, they collected two 24-hour urine specimens while consuming a self-selected diet. Subjects consumed an extremely low-oxalate and normal-calcium diet for 5 days and collected 24-hour urine specimens on the last 3 days of this diet. Next, the subjects took 2 fish oil capsules containing 650-mg eicosapentaenoic acid and 450-mg docosahexaenoic acid twice daily for 30 days. They consumed a self-selected diet on days 1-25 and the controlled diet on days 26-30. Twenty-four-hour urine samples were collected on days 28-30. Excretion levels of urinary analytes including oxalate and glycolate were analyzed. RESULTS: Although there was a significant reduction in urinary oxalate, magnesium, and potassium excretions and an increase in uric acid excretion during the controlled dietary phases compared with the self-selected diet, there were no significant differences in their excretion during controlled diet phases with and without fish oil supplementation. CONCLUSION: These results suggest that fish oil supplementation does not reduce endogenous oxalate synthesis or urinary oxalate excretion in normal adults during periods of extremely low oxalate intake. However, these results do not challenge the previously described reduction in urinary oxalate excretion demonstrated in normal subjects consuming a moderate amount of oxalate in conjunction with fish oil.

Impact of dietary calcium and oxalate, and Oxalobacter formigenes colonization on urinary oxalate excretion.

PURPOSE: Enteric colonization with Oxalobacter formigenes, a bacterium whose main energy source is oxalate, has been demonstrated to decrease the risk of recurrent calcium oxalate kidney stone formation. We assessed the impact of diets controlled in calcium and oxalate contents on urinary and fecal analytes in healthy subjects who were naturally colonized with O. formigenes or not colonized with O. formigenes. MATERIALS AND METHODS: A total of 11 O. formigenes colonized and 11 noncolonized subjects were administered diets controlled in calcium and oxalate contents. We assayed 24-hour urine collections and stool samples obtained on the last 4 days of each 1-week diet for stone risk parameters and O. formigenes levels. Mixed model analysis was used to determine the effects of colonization status on these variables. RESULTS: Urinary calcium and oxalate excretion were significantly altered by the dietary changes in O. formigenes colonized and noncolonized individuals. Mixed model analysis showed significant interaction between colonization status and oxalate excretion on a low calcium (400 mg daily)/moderate oxalate (250 mg daily) diet (p = 0.026). Urinary oxalate excretion was 19.5% lower in O. formigenes colonized subjects than in noncolonized subjects on the low calcium/moderate oxalate diet (mean ± SE 34.9 ± 2.6 vs 43.6 ± 2.6 mg, p = 0.031). CONCLUSIONS: Results suggest that O. formigenes colonization decreases oxalate excretion during periods of low calcium and moderate oxalate intake.

Tubular occlusion of simulated hypersensitive dentin by the combined use of ozone and desensitizing agents.

OBJECTIVE: Ozone was suggested for treatment of hypersensitive dentin. The purpose of this study was to investigate the effect of ozone, with or without the use of desensitizing agents, on patency and occlusion of simulated hypersensitive dentin. MATERIALS AND METHODS: Sixty standardized dentin slabs were randomly divided into six groups: distilled water (Control), ozone treatment, fluoride desensitizer (ALLSolutions, Dentsply), oxalate desensitizer (D/Sense Crystal, Centrix), combined use of ozone/fluoride and combined use of ozone/oxalate. Ozone gas was delivered from OzonyTronX (Mymed). Specimens were evaluated using a scanning electron microscope and digital image analysis before and after treatment. RESULTS: Statistical analysis using ANOVA and Mann-Whitney U-tests revealed significantly lower percentage of tubular occlusion with ozone treatment than distilled water at p ≤ 0.05. Scanning electron microscope photomicrographs of oxalate desensitizer specimens revealed a thick homogenous precipitate with significantly higher percentage of tubular occlusion than fluoride desensitizer and distilled water. Combined use of ozone/fluoride resulted in a significantly higher percentage of tubular occlusion than fluoride desensitizer alone. However, no significant difference was found between oxalate desensitizer and combined use of ozone/oxalate. CONCLUSIONS: The use of ozone gas is a viable adjunct to fluoride-containing desensitizers in enhancing tubular occlusion, but is not effective with oxalate desensitizers.

[Diet and nutrition in nephrolitiasis]. / Dieta e nutrizione nella calcolosi renale.

Nephrolitiasis is a frequent metabolic disease, with a high rate of recurrences. Epidemiological studies reveal that about 80% of all kidney stones are composed of calcium salts (75% calcium oxalate), while about 5% are pure uric acid. Urolithiasis is a multifactorial disease with several underlying disorders of metabolism: that is why diet is an important treatment, especially in the prevention of recurrences. Nutritional intervention is based on a high water intake, physiological calcium intake, modest sodium and animal protein restriction and vitamin C intake <2 gr daily. In case of diagnosed disorders of specific metabolic pathways, a low oxalate, low purine-diet should be advisable.

Effects of calcium supplements on the risk of renal stone formation in a population with low oxalate intake.

It has been speculated that calcium supplement in subjects with low oxalate intake might increase the risk of calcium stone formation due to an increase in calcium absorption without a significant reduction in oxalate absorption. There have been no human studies addressing specifically the effects of taking calcium supplements in populations whose dietary oxalate is low. This study was conducted to determine the effects of calcium supplements on the risk of calcium stone formation in a population with low oxalate intake. Thirty-two healthy male navy privates, 22.7 +/- 1.9 (mean +/- SD) years old, who had oxalate intake of less than 1 mmol/day, a serum creatinine of less than 150 micromol/l, and no history of renal stones, participated in the study. Dietary oxalate was controlled to be under 1 mmol/day throughout the study. Twenty-four hour urine collections for the determination of urinary constituents were obtained at baseline and after taking calcium supplements. Detection of calcium oxalate was performed to assess the risk of calcium oxalate stone formation. The urinary excretion of calcium was significantly elevated above baseline values while taking the calcium supplements (3.48 +/- 2.13 vs 5.17 +/- 2.61 mmol/d, p < 0.05) and urinary oxalate was significantly decreased when the subjects took calcium supplements compared to the corresponding baseline value (0.13 +/- 0.05 vs 0.17 +/- 0.07 mmol/d, p = 0.01). Urinary citrate was significantly elevated when the subjects took calcium supplements compared to the baseline (0.83 +/- 0.57 vs 0.64 +/- 0.39 mmol/d, p = 0.03). There was no significant alteration in the activity products of calcium oxalate while taking the calcium supplements (0.54 +/- 0.25 vs 0.57 +/- 0.22, p = 0.54). The effect of calcium supplements with meals, for the reduction of the risk of calcium stone formation, was unchanged, even in a population whose oxalate intake is rather low. Taking calcium supplements resulted in a reduction in urinary oxalates and an elevation in urinary citrates. Both alterations in urinary constituents counterbalanced the elevation in urinary calcium which resulted from the calcium supplements.

Urinary oxalic acid excretion differs after oral loading of rats with various oxalate salts.

BACKGROUND: To compare urinary oxalate excretion after the oral administration of oxalic acid, disodium oxalate, or calcium oxalate in rats. METHODS: Male Wistar rats were divided into four groups of six rats each and were intravenously hydrated with normal saline, and then were administered normal saline (control group), 10 mg of oxalic acid, equimolar disodium oxalate, or equimolar calcium oxalate via a gastrostomy. Urine specimens were collected just before administration and at hourly intervals up to 5 h afterwards. The urinary oxalate, calcium, magnesium and phosphorus levels were measured. RESULTS: Urinary oxalate excretion peaked at 1-2 h after administration of oxalic acid or equimolar disodium oxalate, while administration of calcium oxalate only caused a small increase of urinary oxalate excretion. Cumulative urinary oxalate excretion during 5 h was 1.69 +/- 0.10 mg (mean +/- SD; 17%), 1.43 +/- 0.13 mg (13%), and 0.22 +/- 0.03 mg (2%) after the administration of oxalic acid, disodium oxalate, and calcium oxalate, respectively. Urinary calcium excretion showed a decrease in the oxalic acid and disodium oxalate groups, while urinary magnesium or phosphorus excretion did not change significantly. CONCLUSION: The upper gastrointestinal tract seems to be the major site of oxalic acid absorption and only free oxalate is absorbed irrespective of whether it is the sodium salt or not. After binding to calcium in the gut, oxalic acid absorption seems to be inhibited in the presence of calcium and this means that calcium oxalate is poorly absorbed (at least in the upper gastrointestinal tract).

Non-nutrient bioactive substances of pulses.

Pulses supply many bioactive substances found in minor amounts in food, but which may have significant metabolic and/or physiological effects. These compounds have long been classified as antinutritional factors, but many studies have reconsidered their impact on health. Some could play a role in the prevention of the major diseases of affluent societies. As these compounds can be beneficial or adverse, depending on conditions, an assessment of their various physiological effects is necessary to determine whether they should be preserved or eliminated in each main nutritional situation.

Nephrolithiasis with unusual initial symptoms.

OBJECTIVE: To describe a less common initial symptom of nephrolithiasis, its diagnostic pitfalls, risk factors, and mimicry of other conditions. Intervention and long-term management of nephrolithiasis is also discussed. CLINICAL FEATURES: A Caucasian man aged 25 years had sudden bilateral inguinal and occasional periumbilical pain. The initial symptom suggested an abdominal pathologic condition; however, costovertebral angle pain followed 1 hour later with no radiation between the 2 anatomic sites. The initial urine dipstick result was negative for hematuria, but a kidney, ureter, and bladder radiograph revealed a smooth 2-mm x 3-mm stone lodged at the left: vesico-ureteral junction. INTERVENTION AND OUTCOME: The patient was referred to a regional university medical center to receive extracorporeal shockwave lithotripsy several days after his initial visit. He was given pain medicine for the waiting period and received daily lumbar spine adjustments with a mild reduction in pain. He eventually received ureteroscopic laser lithotripsy because the shock-wave unit had malfunctioned before his appointment. The fragment analysis showed a calcium oxalate composition, and the patient was advised to lower his intake of oxalates. The patient had become a vegetarian approximately 3 months before this first stone episode. CONCLUSION: Nephrolithiasis is a condition commonly seen in chiropractic practice. Although it is usually easy to recognize, the diagnosis can be elusive if the typical historic factors and diagnostic results are absent or altered. The short-term management of nephrolithiasis is pain management, stone elimination, and the collection of a specimen to identify the composition and underlying metabolic abnormality. Long-term management is to prevent the recurrence of stones. Conservative comanagement by the chiropractic physician can be implemented through nutritional means.

Prevalence of renal stones in a population-based study with dietary calcium, oxalate, and medication exposures.

Little is known about the epidemiology of renal stones, in spite of the relative frequency of this painful condition. This population-based study examined reported renal stone diagnosis in 1,309 women aged 20-92 years to determine whether renal stones are associated with 1) food or water exposures or 2) lower bone mineral density and an increased likelihood of fractures. Results indicated a renal stone prevalence of 3.4%. The average age at diagnosis was 42 years. Renal stone formation was not associated with community of residence, hypertension, bone mineral density, fractures, high-oxalate food consumption, or ascorbic acid from food supplements. Women with renal stones consumed almost 250 mg/day less dietary calcium (p < 0.01) than did women without stones and had a lower energy intake (p < 0.04). The authors' findings do not support the hypothesis that increased dietary calcium is associated with a greater prevalence of renal stones, nor do they identify renal stones as a risk factor for low bone mineral density. Furthermore, lack of other identifiable environmental correlates and the relatively young age at initial diagnosis suggest that genetic components of renal stone formation need further study.

Efectos de la hipnosis con tiopental sódico sobre los mecanismos de regulación glucémica en los perros / Effects of thiopentone hypnosis on blood glucose regulatory mechanisms in the dogs

Si bien se conoce que la hipnosis con tiopental sódico (TPS) no modifica los niveles de glucemia (G) en el hombre, en situaciones basales, se ha demostrado en diversos estudios experimentales que altera la capacidad del organismo para regular los niveles de G cuando se administran cantidades importantes de glucosa. Sin embargo no se conocen completamente los mecanismos que intervienen en la intolerancia hidrocarbonada referida. En el presente trabajo se ha estudiado el efecto de la hipnosis con TPS sobre la respuesta glucémica, insulinémica (IRI) y de los ácidos grasos no esterificados séricos (AGNE) de perros normales en condiciones basales y durante la realización de una prueba de tolerancia endovenosa a la glucosa (PTEG). Comparando los resultados obtenidos con los hallados en animales no anestesiados. Durante la PTEG, los perros anestesiados presentaron intolerancia a la glucosa, caracterizada por una menor respuesta insulínica a la hiperglucemia (menor pico de IRI) y un menor descenso de los niveles de AGNE que fue seguido por un escaso rebote de sus concentraciones séricas comparado al hallado en los perros no anestesiados. Esta alteración se debería a un efecto del agente hipnótico sobre los factores hormonales y nerviosos que regulan los mecanismos pancreáticos y extrapancreáticos de control de la G. (AU)

Efectos de la hipnosis con tiopental sódico sobre los mecanismos de regulación glucémica en los perros / Effects of thiopentone hypnosis on blood glucose regulatory mechanisms in the dogs

Si bien se conoce que la hipnosis con tiopental sódico (TPS) no modifica los niveles de glucemia (G) en el hombre, en situaciones basales, se ha demostrado en diversos estudios experimentales que altera la capacidad del organismo para regular los niveles de G cuando se administran cantidades importantes de glucosa. Sin embargo no se conocen completamente los mecanismos que intervienen en la intolerancia hidrocarbonada referida. En el presente trabajo se ha estudiado el efecto de la hipnosis con TPS sobre la respuesta glucémica, insulinémica (IRI) y de los ácidos grasos no esterificados séricos (AGNE) de perros normales en condiciones basales y durante la realización de una prueba de tolerancia endovenosa a la glucosa (PTEG). Comparando los resultados obtenidos con los hallados en animales no anestesiados. Durante la PTEG, los perros anestesiados presentaron intolerancia a la glucosa, caracterizada por una menor respuesta insulínica a la hiperglucemia (menor pico de IRI) y un menor descenso de los niveles de AGNE que fue seguido por un escaso rebote de sus concentraciones séricas comparado al hallado en los perros no anestesiados. Esta alteración se debería a un efecto del agente hipnótico sobre los factores hormonales y nerviosos que regulan los mecanismos pancreáticos y extrapancreáticos de control de la G.

Effects of potassium oxalate on dentin hypersensitivity in vivo.

This study compared 30% dipotassium oxalate (DO) and 3% monohydrogen-monopotassium oxalate (MO) on the reduction of dentin hypersensitivity in vivo. Four treatments were utilized: (1) distilled water followed by 30% DO; (2) distilled water followed by 3% MO; (3) 30% DO followed by 3% MO and (4) distilled water only. Treatments were randomly assigned so that each of the 17 participants received all four treatments, one per tooth tested. Response to cold at baseline and immediately, 1 week, 2 weeks, and 4 weeks posttreatment was measured. Testing began with water at 20 degrees C and decreased at 5 degrees C intervals until a positive response was obtained or until 0 degrees C was reached. No differences were found for time when compared across treatments. When treatments were compared across time, significant reductions occurred in immediate and 4 week posttreatment measurements for treatment 2. In addition, highly significant reductions occurred in 1 week and 2 week posttreatment measurements for treatment 3. Results suggest a decrease in dentin hypersensitivity following the application of 3% MO alone, and 30% DO followed by 3% MO.