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1.
Effect of calcium and vitamin D supplementation with and without collagen peptides on bone turnover in postmenopausal women with osteopenia.
Argyrou, C, Karlafti, E, Lampropoulou-Adamidou, K, Tournis, S, Makris, K, Trovas, G, Dontas, I, Triantafyllopoulos, IK
Journal of musculoskeletal & neuronal interactions. 2020;(1):12-17
Abstract
OBJECTIVES Collagen peptides (CPs) seem to exert beneficial effects on bone and may have a role as a treatment option. In the present randomized prospective study, we aimed to examine the efficacy, as expressed by changes in P1NP and CTX, and the tolerability of 3-month supplementation of calcium, vitamin D with or without bioactive CPs in postmenopausal women with osteopenia. METHODS Fifty-one female, postmenopausal women with osteopenia were allocated to two groups: Group A received a sachet containing 5 g CPs, 3.6 g calcium lactate (equivalent to 500 mg of elemental calcium) and 400 IU vitamin D3 and group B received a chewable tablet containing 1.25 g calcium carbonate (equivalent to 500 mg of elemental calcium) and 400 IU vitamin D3 daily. RESULTS In group A, the P1NP levels significantly decreased by 13.1% (p<0.001) and CTX levels decreased by 11.4% (p=0.058) within 3 months of supplementation. In group B, P1NP and CTX did not change. Group A presented better compliance in comparison to group B and no adverse events contrary to group B. CONCLUSIONS These findings may reflect the reduction of the increased bone turnover in postmenopausal women with the use of calcium, vitamin D and CPs supplements. The addition of CPs in a calcium and vitamin D supplement may enhance its already known positive effect on bone metabolism. Clinical Trial ID: NCT03999775.
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Chitosan lactate wafer as a platform for the buccal delivery of tizanidine HCl: in vitro and in vivo performance.
El-Mahrouk, GM, El-Gazayerly, ON, Aboelwafa, AA, Taha, MS
International journal of pharmaceutics. 2014;(1-2):100-12
Abstract
Tizanidine HCl is a skeletal muscle relaxant that suffers from extensive hepatic metabolism resulting in 34-40% oral bioavailability. It also suffers from short half-life (2.1-4.2h) that necessitates frequent administration thus reducing patient compliance. In addition, tizanidine HCl is water soluble, so it is a challenging candidate for controlled drug delivery. In our study, tizanidine was encapsulated in chitosan lactate beads cross-linked with sodium tripolyphosphate. The beads were further incorporated into chitosan lactate wafer to be easily applied to buccal mucosa, aiming to bypass the hepatic metabolism. A central composite face-centered design was applied to statistically optimize the formulation variables; tripolyphosphate concentration, chitosan lactate concentration and polymer/drug ratio. The optimized formula suggested by the software composed of; 3.03% tripolyphosphate, 4.92% chitosan lactate and 2.13 polymer/drug ratio. It provided encapsulation efficiency of 56.5% and controlled tizanidine release over 8h. It is also characterized by being mucoadhesive and nonirritant. Pharmacokinetic parameters of tizanidine from the optimized formula were compared to those of the immediate release tablet, Sirdalud(®), as reference in human volunteers using a randomized crossover design. Significant increase was observed for Tmax and AUC(0-∞). The increase in relative bioavailability of TIZ from the optimized formula was 2.27 fold.
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Calcium pre-rinse greatly increases overnight salivary fluoride after a 228 ppm fluoride rinse.
Vogel, GL, Chow, LC, Carey, CM
Caries research. 2008;(5):401-4
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Abstract
BACKGROUND Large increases in salivary fluoride were reported 1 h after a calcium pre-rinse/NaF rinse. AIMS This study examined the persistence of these increases. METHODS 12 subjects rinsed in the evening with water, with a 228 microg/g (ppm) F rinse or with 150 mmol/l calcium lactate followed by a 228 microg/g F rinse. In a second experiment these same patients rinsed with a 912 microg/g F rinse. Saliva samples were obtained the morning after rinsing, centrifuged and the supernatants analyzed. RESULTS The Ca pre-rinse/228 microg/g F rinse induced an increase in overnight salivary F over the 912 microg/g F rinse (approximately 2.5 times) and a statistically significant increase over the 228 mug/g F rinse (approximately 5.5 times). CONCLUSIONS The results suggest that a Ca pretreatment may increase the cariostatic effect of topical F agents.
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Myocardial metabolism is better preserved after blood cardioplegia in infants.
Amark, K, Berggren, H, Björk, K, Ekroth, A, Ekroth, R, Nilsson, K, Sunnegårdh, J
The Annals of thoracic surgery. 2006;(1):172-8
Abstract
BACKGROUND We have previously reported improved hemodynamic function after blood cardioplegia in comparison with crystalloid cardioplegia. Furthermore, lactate was released from the heart after crystalloid cardioplegia but not after blood cardioplegia. The purpose of this study was to determine whether the difference in substrate metabolism between the two cardioplegia methods was restricted to lactate, or whether the difference in metabolic derangement was more extensive. METHODS Thirty consecutive infants with complete atrioventricular septal defects were included in this prospective, randomized, controlled study. Arterial and coronary sinus blood concentrations of substrates and amino acids were measured after weaning from bypass. RESULTS After crystalloid cardioplegia, there was a myocardial uptake of glutamate (p = 0.003), leucine (p = 0.03), lysine (p = 0.003), and beta-hydroxybutyrate (p = 0.004), whereas lactate was released (p = 0.03). After blood cardioplegia, there was a myocardial uptake of free fatty acids (p = 0.01) but no uptake of amino acids and no release of lactate. CONCLUSIONS There are differences in myocardial substrate metabolism between blood cardioplegia and crystalloid cardioplegia, which involve carbohydrates and amino acids. The differences may include lipids but our data in this respect are not conclusive.
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Absence of sustained hyperlactatemia in HIV-infected patients with risk factors for mitochondrial toxicity.
Wohl, DA, Pilcher, CD, Evans, S, Revuelta, M, McComsey, G, Yang, Y, Zackin, R, Alston, B, Welch, S, Basar, M, et al
Journal of acquired immune deficiency syndromes (1999). 2004;(3):274-8
Abstract
BACKGROUND The prevalence of asymptomatic hyperlactatemia among HIV-infected individuals has been reported to be 4% to 36%. This variability may reflect differences in the definition of and risk factors for hyperlactatemia and/or techniques for venous lactate collection. METHODS We examined the prevalence of elevated venous lactate collected in accordance with Adult AIDS Clinical Trials Group (AACTG) guidelines among HIV-infected and nucleoside analogue-treated subjects with risk factors associated with hyperlactatemia. Sustained hyperlactatemia was defined as 2 consecutive levels >or=1.5 but RESULTS Eighty-three subjects were enrolled. Two thirds had >or=2 risk factors, with 11% having >4 risk factors. The median entry venous lactate level was 1.2 mmol/L (range: 0.7-5.1 mmol/L). Two subjects had a lactate level >1.5 times the ULN: 1 with a value of 2.1 times the ULN at entry and a week 2 level of 1.2 times the ULN and a second subject with a week 2 value of 1.9 times the ULN but an entry level of 1.4 times the ULN. The latter subject developed symptomatic lactic acidosis 3 weeks following study discontinuation. CONCLUSIONS Sustained asymptomatic hyperlactatemia among subjects with risk factors associated with hyperlactatemia was not observed when venous lactate was measured in a standardized fashion. One case of hyperlactatemia that evolved into symptomatic lactic acidosis was diagnosed soon after the completion of the study, however. Our findings indicate that asymptomatic hyperlactatemia is either very rare or an artifact of collection technique.
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Administration of a supplement containing both calcium and vitamin D is more effective than calcium alone to reduce secondary hyperparathyroidism in postmenopausal women with low 25(OH)vitamin D circulating levels.
Deroisy, R, Collette, J, Albert, A, Jupsin, I, Reginster, JY
Aging clinical and experimental research. 2002;(1):13-7
Abstract
BACKGROUND AND AIMS Supplementation of postmenopausal women with calcium alone or calcium-vitamin D association was suggested to have positive effects on bone turnover and bone density, as well as to lower fracture incidence. The beneficial effect appears to be mediated by a reduction in parathyroid hormone secretion. Our aim was to compare the respective efficacy of calcium and calcium-vitamin D supplements in reducing serum parathyroid hormone levels in postmenopausal women with prevalent low 25(OH)vitamin D levels. METHODS One hundred consecutive ambulatory postmenopausal women with serum 25(OH)vitamin D levels below 18 ng/mL were included in a randomized, prospective, open label study. For a duration of 90 days, the women were randomly assigned to a daily supplementation of either one tablet of calcium gluconolactate and carbonate (500 mg calcium), or one powder-pack of an association of calcium carbonate (500 mg calcium), citric acid (2.175 gr) and cholecalciferol (200 IU). Changes observed during the 90 days of the study in circulating PTH levels were the primary endpoint, while changes in serum 25(OH)D levels were assessed as secondary endpoint. RESULTS A significant difference was observed between the calcium-vitamin D (CaD) and the calcium (Ca) only groups for changes occurring during the 90 days of the study in PTH (-14.5+/-40% and +2.5+/-46%) (p=0.009) and 25(OH)D (+67+/-77% and +18+/-55%) (p<0.001) circulating levels. PTH changes between baseline and day 90 were significant in the CaD group, but not in the Ca group. The odds ratio for a patient in group Ca to experience an absolute (<12 ng/mL) deficiency in circulating 25(OH)vitamin D levels, compared to a group CaD patient was statistically increased (OR: 3.22, 95% CI: 1.33-7.80). CONCLUSIONS Our results support the recommendation of supplementing postmenopausal women with low circulating levels of 25(OH)vitamin D with a combination of calcium and vitamin D, rather than with calcium alone.
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Changes in lactate and other ions in plaque and saliva after a fluoride rinse and subsequent sucrose administration.
Vogel, GL, Zhang, Z, Chow, LC, Schumacher, GE
Caries research. 2002;(1):44-52
Abstract
The purpose of this study was to examine plaque and saliva composition after a fluoride rinse and subsequent sucrose application. Fifteen subjects accumulated plaque for 48 h, and then rinsed with a fluoride rinse based on 228 microg/g (ppm) Na2SiF6 and some received no rinse. After 60 min, upper and lower buccal molar plaque samples and 1-min saliva samples were collected. The subjects then rinsed with 10% g/g sucrose solution, and 7 and 15 min later, a second and a third set of samples were collected. Plaque fluid and clarified saliva were then recovered from these samples by centrifugation, and the remaining plaque acid extracted. The plaque fluid, centrifuged saliva, and plaque extract samples were then analyzed using micro techniques for pH, free calcium, phosphate, organic acids (plaque fluid and saliva only) and fluoride. Considering both the fluoride rinse and no-rinse groups, the most notable compositional changes in saliva 7 min after the sucrose rinse were pH -0.40 unit, free calcium 0.42 mM, lactate 5.2 mM, phosphate -1.3 mM, and fluoride 2.8 microM; while in plaque fluid, the corresponding changes were pH -1.59 unit, free calcium 1.5 mM, lactate 35 mM, phosphate -1.6 mM and fluoride -26 microM. After sucrose rinsing, undersaturation was found with respect to dicalcium phosphate dihydrate in saliva and plaque fluid and with respect to tooth enamel in some plaque fluid samples. Plaque fluid composition appeared to be strongly influenced by salivary clearance, diffusive loss of ions into the water phase of the rinse, and lower jaw pooling of the sucrose and fluoride components of the rinses. After the experimental rinse, the fluoride concentration in plaque fluid [86 +/- 22 mM (upper molar site), 162 +/- 150 mM (lower molar site)], saliva (26 +/- 18 mM), and whole plaque [99 +/- 97 microg/g (upper molar site), 197 +/- 412 microg/g (lower molar site)] was comparable to the values in previous studies using this rinse. These very high plaque fluid fluoride concentrations, compared with the 'no-rinse' samples, induced an approximately 0.3-unit increase in the plaque fluid pH 7 min after the sucrose rinse, a small decrease (approximately 20%) in lactate production and a modest increase in enamel saturation. Although these changes were all statistically significant, no correlation was found between the decrease in lactate concentration and plaque fluid fluoride, pH or whole plaque fluoride.
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Better correction of metabolic acidosis, blood pressure control, and phagocytosis with bicarbonate compared to lactate solution in acute peritoneal dialysis.
Thongboonkerd, V, Lumlertgul, D, Supajatura, V
Artificial organs. 2001;(2):99-108
Abstract
Lactate solution has been the standard dialysate fluid for a long time. However, it tends to convert back into lactic acid in poor tissue-perfusion states. The aim of this study was to evaluate the efficacy of magnesium (Mg)- and calcium (Ca)-free bicarbonate solution compared with lactate solution in acute peritoneal dialysis (PD). Renal failure patients who were indicated for dialysis and needed acute PD were classified as shock and nonshock groups, and then were randomized to receive either bicarbonate or lactate solution. Twenty patients were enrolled in this study (5 in each subgroup). In the shock group, there were more rapid improvements and significantly higher levels of blood pH (7.40 +/- 0.04 versus 7.28 +/- 0.05, p < 0.05), serum bicarbonate (23.30 +/- 1.46 versus 18.37 +/- 1.25 mmol/L, p < 0.05), systolic pressure (106.80 +/- 3.68 versus 97.44 +/- 3.94 mm Hg, p < 0.05), mean arterial pressure (80.72 +/- 2.01 versus 73.28 +/- 2.41 mm Hg, p < 0.05), percentages of phagocytosis of circulating leukocytes (65.85% +/- 2.22 versus 52.12% +/- 2.71, p < 0.05), and percentages of positive nitroblue tetrazolium (NBT) reduction test without and with stimulation (14.43 +/- 1.93 versus 9.43 +/- 2.12, p < 0.05 and 65.08 +/- 6.80 versus 50.23 +/- 4.21, p < 0.05, respectively) in the bicarbonate subgroup compared with the lactate subgroup. In the nonshock group, blood pH, serum bicarbonate, and phagocytosis assays in both subgroups were comparable. Lactic acidosis was more rapidly recovered and was significantly lower with bicarbonate solution for both shock and nonshock groups (3.63 +/- 0.37 versus 5.21 +/- 0.30 mmol/L, p < 0.05 and 2.92 +/- 0.40 versus 3.44 +/- 0.34 mmol/L, p < 0.05, respectively). Peritoneal urea and creatinine clearances in both subgroups were comparable for both shock and nonshock groups. There was no peritonitis observed during the study. Serum Mg and Ca levels in the bicarbonate subgroup were significantly lower, but no clinical and electrocardiographic abnormality were observed. We concluded that Mg- and Ca-free bicarbonate solution could be safely used and had better outcomes in correction of metabolic acidosis, blood pressure control, and nonspecific systemic host defense with comparable efficacy when compared to lactate solution. It should be the dialysate of choice for acute PD especially in the poor tissue-perfusion states such as shock, lactic acidosis, and multiple organ failure.
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Effect of beta-hydroxy beta-methylbutyrate on the onset of blood lactate accumulation and V(O)(2) peak in endurance-trained cyclists.
Vukovich, MD, Dreifort, GD
Journal of strength and conditioning research. 2001;(4):491-7
Abstract
The purpose of this study was to determine the effect of beta-hydroxy beta-methylbutyrate (HMB) supplementation on maximal oxygen consumption (.V(O)(2)peak) and the onset of blood lactate accumulation (OBLA) in endurance-trained cyclists. Eight cyclists randomly (double blind) completed 3 2-week supplementation periods (HMB, 3g.day(-1); leucine [LEU], 3g.day(-1); placebo [CON], 3g.day(-1)) followed by a 2-week washout period. Testing consisted of a graded cycle ergometry test to measure .V(O)(2)peak and OBLA, the .V(O)(2) at 2 mM blood lactate. .V(O)(2)peak was unaffected by HMB (4.0 +/- 1.4%), LEU (-1.9 +/- 1.3%), and CON (-2.6 +/- 2.6%). HMB resulted in a greater time to reach .V(O)(2)peak, whereas LEU and CON did not affect this time (HMB, 3.6 +/- 1.5 min, LEU, -1.2 +/- 1.5 min; CON, -3.6 +/- 3.5 min). Lactate accumulation peak was unaffected by supplementation (HMB, 8.1 +/- 1.1 mM; LEU, 6.2 +/- 0.8 mM; CON, 7.5 +/- 1.3 mM). OBLA increased with HMB (9.1 +/- 2.4%) and LEU (2.1 +/- 1.5%), but not in the CON trial (0.75 +/- 2.1%). Blood glucose was significantly greater during the HMB trial compared with the LEU trial. It is concluded that HMB supplementation may have positive affects on performance by increasing the onset of blood lactate accumulation; however, the mechanism is unknown.
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The effect of glycemic index on plasma glucose and lactate levels during incremental exercise.
Stannard, SR, Constantini, NW, Miller, JC
International journal of sport nutrition and exercise metabolism. 2000;(1):51-61
Abstract
Consumption of low glycemic index (GI) foods before submaximal endurance exercise may be beneficial to performance. To test whether this may also be true for high intensity exercise, 10 trained cyclists began an incremental exercise test to exhaustion 65 min after consuming equal carbohydrate portions of glucose (HGI), pasta (LGI), and a noncarbohydrate control (PL). Time to fatigue did not differ significantly (p = 0.05) between treatments. Plasma glucose concentration was significantly lower after LGI vs. HGI from 15 to 45 min of rest postprandial. During exercise, plasma glucose concentration was significantly lower after HGI vs. LGI from 200 W until exhaustion. Plasma lactate concentration following HGI was significantly higher than PL from 30 min of rest postprandial through to the end of the 200-W workload. Plasma lactate concentration following LGI was significantly lower than after HGI from 45 min of rest postprandial through to the end of the 100-W workload. At higher exercise intensities, there was no significant difference in plasma lactate levels between treatments. These findings suggest that a high GI carbohydrate meal (1 g/kg body wt) 65 min prior to exercise decreases plasma glucose and increases plasma lactate levels compared to a low GI meal, but not enough to be detrimental to incremental exercise performance.