Oral Bolus Dose Research Articles

Effects of High Dose Bolus Cholecalciferol on Free Vitamin D Metabolites, Bone Turnover Markers and Physical Function.

High dose bolus cholecalciferol supplementation has been associated with falls and fracture, and this does not appear to be due to hypercalcaemia. The primary aim of this study was to determine the change in free vitamin D and metabolites after high dose bolus supplementation. This was a single centre, double-blinded, randomised, controlled trial of three different oral bolus doses of vitamin D3 (50,000 IU, 150,000 IU, and 500,000 IU) in otherwise healthy, vitamin D deficient (total 25-hydroxylated vitamin 25(OH)D < 30 nmol/L) postmenopausal women. Thirty-three women were randomized to one of the three treatment groups. Twenty-seven vitamin D sufficient (25(OH)D > 50 nmol/L) postmenopausal women were recruited as a concurrent control group. Participants attended five study visits over three months. We measured total 25(OH)D3 and free 25(OH)D, total and free 1,25(OH)2D, parathyroid hormone, fibroblast-growth factor-23, serum calcium, ionised calcium, urinary calcium excretion, and bone turnover markers (procollagen I N-propeptide (PINP), serum C-telopeptides of type I collagen (CTX-I) and Osteocalcin (OC)). We assessed muscle strength and function with grip strength and a short physical performance battery. Postural blood pressure and aldosterone:renin ratio (ARR) was also measured. Total 25(OH)D3 and free 25(OH)D increased in response to dose, and there were proportionate increases in total and free metabolites. Treatment did not affect serum calcium, postural blood pressure, ARR, or physical function. Bone turnover markers increased transiently one week after administration of 500,000 IU. High dose bolus cholecalciferol supplementation does not cause disproportionate increases in free vitamin D or metabolites. We did not identify any effect on blood pressure regulation or physical function that would explain increased falls after high dose treatment. A transient increase in bone turnover markers one week after a 500,000 IU bolus suggests that very high doses can have acute effects on bone metabolism, but the clinical significance of this transient increase is uncertain.

Pharmacokinetics of doxycycline hyclate in pigs with a new feed premix formulation.

This study aimed to evaluate the administration of doxycycline hyclate in a long-acting pharmaceutical preparation in pigs when administered either adlibitum as a feed medication or an oral bolus dose. In all instances, the studied dose was 20 mg/kg b.w. A total of 48 healthy crossbred, castrated male pigs (Landrace-Yorkshire) weighing 23 ± 4.3 kg were included in this trial. They were randomly assigned to six groups as follows: two groups for the experimental prototype 1 of doxycycline hyclate administering it adlibitum (Fad-lib) or as forced bolus (Fbolus); two groups for the experimental prototype 2 of doxycycline hyclate as for the former groups (FCad-lib and FCbolus), and two control groups receiving the same dose of doxycycline hyclate, but of a commercial premix, also as previously explained (Cbolus and Cad-lib). Statistical analysis of the mean pharmacokinetic values was carried out with Kruskal-Wallis and Dunn's tests. The relative bioavailability (Fr) of the best prototype, when administered adlibitum (FCad-lib), was five times larger than the reference group (Cadlib). These results allow the proposal that the referred differences achieved in the presented prototypes can mark a notable clinical difference, particularly in pathogens with some resistance.

Comparative urine metabolomics of mice treated with non-toxic and toxic oral doses of (-)-epigallocatechin-3-gallate.

The green tea polyphenol, (-)-epigallocatechin-3-gallate (EGCG), has been studied for its potential positive health effects, but human and animal model studies have reported potential toxicity at high oral bolus doses. This study used liquid chromatography-mass spectrometry-based metabolomics to compare the urinary EGCG metabolite profile after administration of a single non-toxic (100 mg kg-1) or toxic (750 mg kg-1) oral bolus dose to male C57BL6/J mice to better understand how EGCG metabolism varies with dose. EGCG metabolites, including methyl, glucuronide, sulfate, and glucoside conjugates, were tentatively identified based on their mass to charge (m/z) ratio and fragment ion patterns. Partial least squares discriminant analysis (PLS-DA) results showed clear separation of the urine metabolite profiles between treatment groups. The most differentiating metabolites in the negative and positive ion modes were provisionally identified as di-glucuronidated EGCG quinone and di-glucuronidated EGCG, respectively. The presence of EGCG oxidation products at toxic dose is consistent with studies showing that EGCG toxicity is associated with oxidative stress. Relative amounts of methylated metabolites increased with dose to a lesser extent than glucuronide and sulfate metabolites, indicating that methylation is more prominent at low doses, whereas glucuronidation and sulfation may be more important at higher doses. One limitation of the current work is that the lack of commercially-available EGCG metabolite standards prevented absolute metabolite quantification and identification. Despite this limitation, these findings provide a basis for better understanding the dose-dependent changes in EGCG metabolism and advance studies on how these differences may contribute to the toxicity of high doses of EGCG.

Rapidly Increasing Serum 25(OH)D Boosts the Immune System, against Infections-Sepsis and COVID-19.

Vitamin D deficiency is a global public health problem, a pandemic that commonly affects the elderly and those with comorbidities such as obesity, diabetes, hypertension, respiratory disorders, recurrent infections, immune deficiency, and malignancies, as well as ethnic minorities living in temperate countries. The same groups were worst affected by COVID-19. Since vitamin D deficiency weakens the immune system, it increases the risk of infections, complications, and deaths, such as from sepsis and COVID-19. Deficiency can be remedied cost-effectively through targeted food fortification, supplementation, and/or daily safe sun exposure. Its endocrine functions are limited to mineral metabolism, musculoskeletal systems, specific cell membrane interactions, and parathyroid gland functions. Except for the rapid, endocrine, and cell membrane-based non-genomic functions, all other biological and physiological activities of vitamin D depend on the adequate intracellular synthesis of 1,25(OH)2D (calcitriol) in peripheral target cells via the genome. Calcitriol mediates autocrine (intracrine) and paracrine signalling in immune cells, which provides broader, protective immune functions crucial to overcoming infections. The synthesis of 1,25(OH)2D (calcitriol) in peripheral target cells is dependent on diffusion and endocytosis of D3 and 25(OH)D from the circulation into them, which requires maintenance of serum 25(OH)D concentration above 50 ng/mL. Therefore, in acute infections such as sepsis and respiratory infections like COVID-19, it is necessary to rapidly provide its precursors, D3 and 25(OH)D, through the circulation to generate adequate intracellular calcitriol. Immune defence is one of the crucial non-hormonal functions of vitamin D. A single oral (bolus) dose or divided upfront loading doses between 100,000 and 500,000 IU, using 50,000 IU vitamin D3 increase the serum 25(OH)D concentrations to a therapeutic level of above 50 ng/mL that lasts between two to three months. This takes three to five days to raise serum 25(OH)D. In contrast, a single oral dose of calcifediol (0.014 mg/kg body weight) can generate the needed 25(OH)D concentration within four hours. Considering both D3 and 25(OH)D enter immune cells for generating calcitriol, using the combination of D3 (medium-term) and calcifediol (immediate) is cost-effective and leads to the best clinical outcome. To maximise protection against infections, particularly to reduce COVID-19-associated complications and deaths, healthcare workers should advise patients on safe sun exposure, adequate vitamin D supplementation and balanced diets containing zinc, magnesium, and other micronutrients to support the immune system. Meanwhile, governments, the World Health Organisation, the Centers for Disease Control, and governments should consider similar recommendations to physicians and the public, change the outdated vitamin D and other micronutrient recommendations directed to their population, and organise targetted food fortification programs for the vulnerable groups. This article discusses a rational approach to maintaining a sustained serum 25(OH)D concentration above 50 ng/mL, necessary to attain a robust immune system for overcoming infections. Such would cost-effectively improve the population’s health and reduce healthcare costs. It also describes three cost-effective, straightforward protocols for achieving and sustaining therapeutic serum 25(OH)D concentrations above 50 ng/mL (>125 nmol/L) to keep the population healthy, reduce absenteeism, improve productivity, and lower healthcare costs.

Analysis and interpretation of pharmacokinetic studies following DEET administration to rats, dogs, and humans

Pharmacokinetic studies on the undiluted insect repellent active ingredient, DEET, were assessed for relevance to exposure assessment for humans. Five studies designed to define the DEET plasma concentration profiles of systemic exposure occurring at the respective NOAELs for two laboratory species using dermal and/or oral exposure scenarios and human volunteers at the 95th percentile of consumer use were undertaken to support EPA re-registration. The studies reported herein demonstrate that the DEET plasma concentration for Sprague-Dawley rats and Beagle dogs at the respective NOAELs following oral bolus dosing is much greater in terms of Cmax and AUC than that achieved following human dermal administration at the 95th percentile of consumer use. In addition, these plasma level data confirm that a high-dose rat subchronic dermal toxicity study with DEET is the most relevant model for human safety assessment of this topically applied insect repellent active ingredient. Therefore, utilization of pharmacokinetic plasma level data is important to exposure assessment of DEET and significantly reduces uncertainty in human health safety assessment.

Continuous oral stable isotope ingestion to measure whole-body protein turnover.

Protein kinetic responses to nutrition and exercise interventions are commonly evaluated using a primed-constant infusion of stable isotope tracers. While this methodology is state-of-the-art, the required preparation at a certified pharmacy makes the utilization of isotope infusion both expensive and logistically cumbersome. Oral tracer ingestion has been used to quantify 24-hwhole-body protein status; however, this does not permit examination of acute interventional effects. Ingestion of a priming bolus, followed by continuous ingestion of stable isotope tracer in a 'sip feeding' fashion may provide a more feasible alternative for quantifying acute kinetic responses. Therefore, the purpose of this study was to evaluate the viability of a primed continuous oral sip-ingestion method of stable isotope tracers for the evaluation of whole-body protein kinetics. In a randomized, crossover design, eight healthy adults (63% female; Age: 29.4±5.8yrs; BMI: 24.3±2.7kg/m2) completed two, two-period stable isotope oral ingestion studies, consisting of a 3hbasal fasted period, followed by a 4-hpost-ingestion period. After the basal period, subjects ingested either 6.3g (Low) or 12.6g (High) of an essential amino acid (EAA) enriched whey protein supplement. The continuous oral sip-feed method was initiated with a primed oral bolus dose of L-[ring-2H5]phenylalanine, L-[ring-2H2]tyrosine, and L-[ring-2H4]tyrosine, followed by oral sip doses of L-[ring-2H5]phenylalanine, L-[ring-2H2]tyrosine every 10min to approximate steady state tracer enrichment. Blood samples were taken throughout the basal and post-meal periods to determine tracer enrichment. Whole-body net protein balance (NB), synthesis (PS), breakdown (PB), and exogenous hydroxylation were calculated for each period. Repeated measure ANOVAs (treatment×time) were used to assess differences in protein kinetics. Using the sip feed method, NB, PS, and hydroxylation were significantly increased with ingestion of protein (p<0.05) during the postprandial period, regardless of amount of protein ingested; ΔNB from the postabsorptive to postprandial period was significantly greater for high compared to low protein (p=0.026; low=6.2±5.1g protein·240min-1; high=11.8±3.9g protein·240min-1). The current study provides preliminary evidence that continuous oral sip-feeding of stable isotope tracer is a feasible method that provides physiologically relevant measures of protein metabolism. Assessments of variance and individual responses revealed high measurement variability with the sip-feed method compared to previously published constant infusion responses, but ΔNB, ΔPS, and ΔPB were comparable. In situations where constant infusion is not feasible, oral sip-feeding could be used as an alternative method for measurement of acute, postprandial protein metabolism.

Assessment of the Anti-Allodynic and Anti-Hyperalgesic Efficacy of a Glycine Transporter 2 Inhibitor Relative to Pregabalin, Duloxetine and Indomethacin in a Rat Model of Cisplatin-Induced Peripheral Neuropathy.

Cisplatin, which is a chemotherapy drug listed on the World Health Organisation’s List of Essential Medicines, commonly induces dose-limiting side effects including chemotherapy-induced peripheral neuropathy (CIPN) that has a major negative impact on quality of life in cancer survivors. Although adjuvant drugs including anticonvulsants and antidepressants are used for the relief of CIPN, analgesia is often unsatisfactory. Herein, we used a rat model of CIPN (cisplatin) to assess the effect of a glycine transporter 2 (GlyT2) inhibitor, relative to pregabalin, duloxetine, indomethacin and vehicle. Male Sprague-Dawley rats with cisplatin-induced mechanical allodynia and mechanical hyperalgesia in the bilateral hindpaws received oral bolus doses of the GlyT2 inhibitor (3–30 mg/kg), pregabalin (3–100 mg/kg), duloxetine (3–100 mg/kg), indomethacin (1–10 mg/kg) or vehicle. The GlyT2 inhibitor alleviated both mechanical allodynia and hyperalgesia in the bilateral hindpaws at a dose of 10 mg/kg, but not at higher or lower doses. Pregabalin and indomethacin induced dose-dependent relief of mechanical allodynia but duloxetine lacked efficacy. Pregabalin and duloxetine alleviated mechanical hyperalgesia in the bilateral hindpaws while indomethacin lacked efficacy. The mechanism underpinning pain relief induced by the GlyT2 inhibitor at 10 mg/kg is likely due to increased glycinergic inhibition in the lumbar spinal cord, although the bell-shaped dose–response curve warrants further translational considerations.

Characterization of the Onset, Progression, and Reversibility of Morphological Changes in Mouse Lung after Pharmacological Inhibition of Leucine-Rich Kinase 2 Kinase Activity.

Gain-of-function mutations in leucine-rich kinase 2 (LRRK2) are associated with increased incidence of Parkinson disease (PD); thus, pharmacological inhibition of LRRK2 kinase activity is postulated as a disease-modifying treatment of PD. Histomorphological changes in lungs of nonhuman primates (NHPs) treated with small-molecule LRRK2 kinase inhibitors have brought the safety of this treatment approach into question. Although it remains unclear how LRRK2 kinase inhibition affects the lung, continued studies in NHPs prove to be both cost- and resource-prohibitive. To develop a tractable alternative animal model platform, we dosed male mice in-diet with the potent, highly selective LRRK2 kinase inhibitor MLi-2 and induced histomorphological changes in lung within 1 week. Oral bolus dosing of MLi-2 at a frequency modeled to provide steady-state exposure equivalent to that achieved with in-diet dosing induced type II pneumocyte vacuolation, suggesting pulmonary changes require sustained LRRK2 kinase inhibition. Treating mice with MLi-2 in-diet for up to 6 months resulted in type II pneumocyte vacuolation that progressed only modestly over time and was fully reversible after withdrawal of MLi-2. Immunohistochemical analysis of lung revealed a significant increase in prosurfactant protein C staining within type II pneumocytes. In the present study, we demonstrated the kinetics for onset, progression, and rapid reversibility of chronic LRRK2 kinase inhibitor effects on lung histomorphology in rodents and provide further evidence for the derisking of safety and tolerability concerns for chronic LRRK2 kinase inhibition in PD. SIGNIFICANCE STATEMENT: We have defined a mouse model by which the on-target lung effects of leucine-rich kinase 2 (LRRK2) kinase inhibition can be monitored, whereas previous in vivo testing relied solely on nonhuman primates. Data serve to derisk long-term treatment with LRRK2 kinase inhibitors, as all lung changes were mild and readily reversible.

Assessment of the anti-allodynic efficacy of a glycine transporter 2 inhibitor relative to pregabalin and duloxetine in a rat model of prostate cancer-induced bone pain.

The pathobiology of prostate cancer-induced bone pain (PCIBP) is underpinned by both inflammatory and neuropathic components. Here, we used a rat model of PCIBP to assess the analgesic efficacy of a glycine transporter 2 (GlyT2) inhibitor (N-(6-((1,3-dihydroxypropan-2-yl)amino)-2-(dimethylamino)pyridin-3-yl)-3,5-dimethoxy-4-(4-(trifluoromethyl)phenoxy) benzamide) relative to two clinically available adjuvant drugs that are recommended for the relief of neuropathic pain, viz, pregabalin and duloxetine. PCIBP was induced in male Wistar Han rats following intra-tibial injection (ITI) of rat prostate cancer (AT3B) cells into the left tibia. Sham-rats received an ITI of heat-killed AT3B cells. PCIBP rats with fully developed mechanical allodynia in the ipsilateral hindpaws as assessed using von Frey filaments, received single oral (p.o.) bolus doses of the GlyT2 inhibitor (3-30mg/kg), pregabalin (3-100mg/kg), duloxetine (3-100mg/kg), or vehicle. Baseline paw withdrawal thresholds (PWTs) were determined in the ipsilateral (injured side) and contralateral hindpaws immediately prior to dosing and at scheduled times for 3h post dosing in individual animals. Single oral bolus doses of the GlyT2 inhibitor (3-30mg/kg) evoked partial pain relief at the doses tested in the ipsilateral hindpaws of PCIBP rats without any discernible behavioural side effects. By contrast, single oral bolus doses of pregabalin at 10-100mg/kg evoked dose-dependent and complete alleviation of mechanical allodynia. By comparison, single oral bolus doses of duloxetine at doses up to 100mg/kg lacked efficacy. Oral administration of this GlyT2 inhibitor evoked partial pain relief in PCIBP rats and did not evoke central nervous system side effects in contrast to GlyT2 inhibitors reported by others.

Oral Dosing of Dihydromethysticin Ahead of Tobacco Carcinogen NNK Effectively Prevents Lung Tumorigenesis in A/J Mice.

Our early studies demonstrated an impressive chemopreventive efficacy of dihydromethysticin (DHM), unique in kava, against tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis in A/J mice in which DHM was supplemented in the diet. The current work was carried out to validate the efficacy, optimize the dosing schedule, and further elucidate the mechanisms using oral bolus dosing of DHM. The results demonstrated a dose-dependent chemopreventive efficacy of DHM (orally administered 1 h before each of the two NNK intraperitoneal injections, 1 week apart) against NNK-induced lung adenoma formation. Temporally, DHM at 0.8 mg per dose (∼32 mg per kg body weight) exhibited 100% lung adenoma inhibition when given 3 and 8 h before each NNK injection and attained >93% inhibition when dosed at either 1 or 16 h before each NNK injection. The simultaneous treatment (0 h) or 40 h pretreatment (-40 h) decreased lung adenoma burden by 49.8% and 52.1%, respectively. However, post-NNK administration of DHM (1-8 h after each NNK injection) was ineffective against lung tumor formation. In short-term experiments for mechanistic exploration, DHM treatment reduced the formation of NNK-induced O6-methylguanine (O6-mG, a carcinogenic DNA adduct in A/J mice) in the target lung tissue and increased the urinary excretion of NNK detoxification metabolites as judged by the ratio of urinary NNAL-O-gluc to free NNAL, generally in synchrony with the tumor prevention efficacy outcomes in the dose scheduling time-course experiment. Overall, these results suggest DHM as a potential chemopreventive agent against lung tumorigenesis in smokers, with O6-mG and NNAL detoxification as possible surrogate biomarkers.

In vivo kinetic study of the materno-fetal fatty acid transfer in obese and normal weight pregnant women

AbstractIntroduction:Placental function can be modified by maternal obesity affecting the materno-fetal fatty acid transport process. We analyze for the first time the in vivo materno-fetal kinetic transfer of fatty acids (FA) labeled with stable isotopes in control and obese pregnant women.Materials and Methods:Labelled FA with similar metabolism (stearic acid: 13C-SA, palmitic acid: 13C-PA and oleic acid: 13C-OA) were orally administered at -4 h, -8 h, and -12 h, respectively prior to elective caesarean section to 10 pregnant women with a body mass index (BMI) &gt; 30 and 10 with BMI 25–30 (control). Placenta, venous and arterial cord blood were collected obtaining a wide range of FA enrichments. A combined experimental and computational modeling analysis was applied.Results:FA Fractional synthesis rate (FSR) in placenta was 11–12% per hour. No differences were observed between control and normo-lipidemic obese pregnant women. It was not possible to estimate FA FSR in cord blood with this oral bolus dose approach. Computational modelling demonstrated a good fit to the data when all maternal plasma lipid classes were included but not with modelling based only on the non-esterified FA fraction (NEFA). The estimated materno-fetal 13C-FA transfer was around 1%.Conclusions:Our approach using multiple 13C-FA tracers allowed us to estimated FSR in placental/maternal plasma but not in fetal/maternal compartments. Computational modelling showed a consistent time course of placental 13C-FA transfer and predicted total fetal FA accumulation during the experiment. We conclude that in addition to NEFA in the maternal circulation, maternal plasma VLDL and other lipoproteins are important contributors to placental FA transfer to the fetus.

In vivo kinetic study of materno-fetal fatty acid transfer in obese and normal weight pregnant women.

Placental structure and function can be modified as a result of maternal obesity affecting materno-fetal fatty acids (FA) transport. We report for the first time, in humans and in vivo, the kinetics of placental FA transfer in normo-weight and in normolipemic obese pregnant women using stable isotopes. The administration of different tracer FA with similar behaviour to the mother at different time points allows the collection of kinetic information on materno-fetal transfer of FA despite only one sample of placenta and cord can be collected per subject. Computational modelling showed a good fit to the data when considering all maternal plasma lipid classes but not when based only on non-esterified FA. The novel approach using multiple tracer FA administration combined with computational modelling shows a consistent time course of placental tracer FA and predicted total FA accumulation. We analyse for the first time the in vivo materno-fetal kinetic transfer of fatty acids (FA) labelled with stable isotopes in control and obese (OB) pregnant women. Labelled FA with a similar metabolism (stearic acid: 13 C-SA; palmitic acid: 13 C-PA; oleic acid: 13 C-OA) were orally administered at -4h, -8h and -12h, respectively prior to elective caesarean section to 10 pregnant women with a body mass index >30 (OB) and 10 with a body mass index in the range 20-25 (NW). Placenta, venous and arterial cord blood were collected obtaining a wide range of FA enrichments. A combined experimental and computational modelling analysis was applied. FA fractional synthesis rate (FSR) in placenta was 11-12%h-1 . No differences were observed between NW and normo-lipidemic OB. It was not possible to estimate FA FSR in cord blood with this oral bolus dose approach. Computational modelling demonstrated a good fit to the data when all maternal plasma lipid classes were included but not with modelling based only on the non-esterified FA fraction. The estimated materno-fetal 13 C-FA transfer was ∼1%. In conclusion, our approach using multiple 13 C-FA tracers allowed us to estimated FSR in placental/maternal plasma but not in fetal/maternal compartments. Computational modelling showed a consistent time course of placental 13 C-FA transfer and predicted total fetal FA accumulation during the experiment. We conclude that, in addition to non-esterified FA fraction in the maternal circulation, maternal plasma very low-density lipoprotein and other lipoproteins are important contributors to placental FA transfer to the fetus.

Differential Effects of Oral Boluses of Vitamin D2 vs Vitamin D3 on Vitamin D Metabolism: A Randomized Controlled Trial.

ContextVitamin D2 and vitamin D3 have been hypothesized to exert differential effects on vitamin D metabolism.ObjectiveTo compare the influence of administering vitamin D2 vs vitamin D3 on metabolism of vitamin D3.MethodsWe measured baseline and 4-month serum concentrations of vitamin D3, 25-hydroxyvitamin D3 [25(OH)D3], 25-hydroxyvitamin D2, 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3], 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3], and 4β,25-dihydroxyvitamin D3 [4β,25(OH)2D3] in 52 adults randomized to receive a total of four oral bolus doses of 2.5 mg vitamin D2 (n = 28) or vitamin D3 (n = 24) over four months. Metabolite-to-parent compound ratios were calculated to estimate hydroxylase activity. Pairwise before vs after comparisons were made to evaluate effects of vitamin D2 and vitamin D3 on metabolism of vitamin D. Mean postsupplementation metabolite-to-parent ratios were then compared between groups.ResultsVitamin D2 was less effective than vitamin D3 in elevating total serum 25(OH)D concentration. Vitamin D2 suppressed mean four-month serum concentrations of 25(OH)D3, 24R,25(OH)2D3, 1α,25(OH)2D3, and 4β,25(OH)2D3 and mean ratios of 25(OH)D3 to D3 and 1α,25(OH)2D3 to 25(OH)D3, while increasing the mean ratio of 24R,25(OH)2D3 to 25(OH)D3. Vitamin D3 increased mean four-month serum concentrations of 25(OH)D3, 24R,25(OH)2D3, 1α,25(OH)2D3, and 4β,25(OH)2D3 and the mean ratio of 24R,25(OH)2D3 to 25(OH)D3. Participants receiving vitamin D2 had lower mean postsupplementation ratios of 25(OH)D3 to vitamin D3 and 1α,25(OH)2D3 to 25(OH)D3 than those receiving vitamin D3. Mean postsupplementation ratios of 24R,25(OH)2D3 to 25(OH)D3 and 4β,25(OH)2D3 to 25(OH)D3 did not differ between groups.ConclusionsBolus-dose vitamin D2 is less effective than bolus-dose vitamin D3 in elevating total serum 25(OH)D concentration. Administration of vitamin D2 reduces 25-hydroxylation of vitamin D3 and 1-α hydroxylation of 25(OH)D3, while increasing 24R-hydroxylation of 25(OH)D3.

Impact of the Chinese herbal medicines on dual antiplatelet therapy with clopidogrel and aspirin: Pharmacokinetics and pharmacodynamics outcomes and related mechanisms in rats

Ethnopharmacological relevanceDual antiplatelet therapy (DAPT) with aspirin (ASA) and clopidogrel (CLP) has been consistently shown clinical effectiveness in patients with coronary artery disease. According to the literature, four traditional Chinese medicine (TCM) herbs effective for prevention cardiovascular diseases, namely Radix Salvia Miltiorrhiza (Red sage root, Danshen), Radix Pueraria Lobata (Kudzu root, Gegen), Radix Angelica Sinensis (Angelica root, Danggui), and Rhizoma Ligusticum chuanxiong (Szehuan lovage rhizome, Chuanxiong), are of high potential to be co-administered during DAPT. Since all these herbs are blood vitalizing medicines and can promote blood circulation and eliminate blood stasis, it was hypothesized that they may potentially alter the clinical outcomes of DAPT with clopidogrel and aspirin. Aim of studyThe current study is proposed aiming to preliminarily evaluate the impact of these four commonly used Chinese medicinal herbs on the pharmacokinetics and pharmacodynamics of the combination therapy with clopidogrel and aspirin and its relevant outcomes and mechanisms. Materials and methodsIn order to mimic the standard dosing regimen for DAPT in human, various Sprague-Dawley rats treatment groups were received a bolus oral dose of DAPT on day 1 followed by DAPT for consecutive 13 days in absence and presence of orally co-administered four TCM herbs (Danshen, Gegen, Danggui and Chuanxiong) at their low and high doses. On day 14, serial blood samples were collected after dosing to obtain the plasma concentrations of ASA, CLP and their corresponding metabolites by LC/MS/MS. At the end of last blood sampling point of each rat, about 4.5 ml of whole blood were collected to estimate the prothrombin time from each treatment groups. After all the blood sampling, the rats were sacrificed followed by collecting their livers for evaluations of enzyme activities and expressions in the related liver microsome preparations and stomach tissues for evaluations of their potential ulcer index. In addition, gene expression and protein levels of related biomarkers (COX-1, COX-2, P2Y12) in rat livers were measured by RT-PCR and Western blot, respectively, and compared among different treatment groups. ResultsCo-administration of Gegen and Danggui significantly altered the pharmacokinetics of ASA and CLP in DAPT with increased systemic exposure of ASA and CLP respectively. Although minimal impact on aspirin esterase activity for all co-administered herbs, significant inhibition on rCyp2c11 and carboxylesterase activities were observed for DAPT with Danshen, Gegen and Danggui co-treatment. In addition, significantly longer PT were found in all DAPT treatment groups. However, a trend of decrease in PT of DAPT in presence of Gegen, Danggui and Chuanxiong was noticed. Nevertheless, all the treatments did not cause detectable changes in COX and P2Y12 mRNA and protein expressions. ConclusionAmong the four studied TCMs, it was demonstrated that co-administration of Gegen and Danggui could lead to altered pharmacokinetics of DAPT with significant inhibition on rCyp2c11 and carboxylesterase activities. Although Gegen, Danggui and Chuanxiong might potentially offset the anticoagulant activity of DAPT, the overall pharmacodynamics outcome was not considered to be harmful due to lack of risk in bleeding, which warrant further verification for its clinical impact.

Oral versus single intravenous bolus dose antibiotic prophylaxis against postoperative surgical site infection in external dacryocystorhinostomy for primary acquired nasolacrimal duct obstruction - A randomized study.

Purpose:To compare the efficacy of a single perioperative bolus dose of intravenous antibiotic versus postoperative oral antibiotic prophylaxis for prevention of surgical site infection (SSI) in external dacryocystorhinostomy (DCR) for primary acquired nasolacrimal duct obstruction (PANDO).Methods:This was a prospective randomized controlled study with a noninferiority design. Patients undergoing external DCR surgery were randomized into two groups A and B. Patients in group A received a single bolus dose of intravenous cefazolin 1 g at surgery, whereas those in group B received oral cephalexin 500 mg postoperatively twice a day for 5 days. Allocation concealment was ensured by sequentially numbered opaque sealed envelopes (SNOSEs). Both groups were advised identical postoperative local wound care regimens. Any clinical evidence of SSI at 4 weeks of follow-up in either group was the main outcome measure.Results:In all, 338 patients randomized into two groups of 169 patients each participated in this study. At follow-up of 4 weeks, only one patient in group B developed postoperative SSI. None in group A developed postoperative SSI. Other potential risk factors for postoperative SSI were also analyzed by univariate and multivariate analyses but none achieved statistical significance in either group.Conclusion:Our results demonstrate that a single bolus dose of perioperative intravenous antibiotic offers adequate prophylaxis against postoperative SSI and compares favorably with the more commonly used oral antibiotic prophylaxis in external DCR for PANDO in our population and our practice scenario.

Effect of 16-weeks vitamin D replacement on calcium-phosphate homeostasis in overweight and obese adults

This randomised placebo-controlled trial aimed to determine the effect of 16-weeks cholecalciferol supplementation on calcium-phosphate homeostasis and bone mineral density (BMD) in overweight and obese adults. Fifty-four vitamin D-deficient (25OHD<50 nmol/L), overweight and obese adults (mean age 32 ± 8.5 years) were included in the trial. Participants were randomly assigned to receive either a bolus oral dose of 100,000 IU cholecalciferol followed by 4000 IU cholecalciferol/d or a matching placebo for 16 weeks. Before and after the intervention, serum calcium, phosphate, 25-hydroxyvitamin D [25(OH)D], intact parathyroid hormone (iPTH) and C-terminal plasma fibroblast growth factor-23 (cFGF-23) concentrations were measured. Whole-body BMD was assessed using dual-energy X-ray absorptiometry (DXA) and diet and sun exposure were assessed using self-administered questionnaires. There were no significant differences in baseline characteristics between the vitamin D and placebo group. After 16-weeks of vitamin D supplementation, mean changes in 25(OH)D concentration were higher in the vitamin D group (57 nmol/L 95% CI 49, 65) compared with placebo (2 nmol/L 95% CI -4, 8), P < 0.001. Additionally, iPTH concentrations declined in the vitamin D group (−1.19 pmol/L 95% CI −1.9, −0.47) compared with placebo (0.14 pmol/L 95% CI −0.49, 0.77), P = 0.006. There were no significant differences in calcium, phosphate, iPTH and cFGF-23 concentrations and whole-body BMD between vitamin D and placebo at follow-up. Inverse correlations were observed between mean change in serum iPTH and cFGF-23 in the vitamin D group only (r=-0.41, P = 0.029). In individuals with greater vitamin D deficiency at baseline (25(OH)D < 30 nmol/L), there was a significant increase in mean whole-body BMD (0.01 g/cm2, 95% CI 0.001, 0.025) however, the mean change in BMD was not different between vitamin D and placebo groups in this sub-group analysis. We conclude that cholecalciferol supplementation for 16 weeks increases serum 25(OH)D concentrations and reduces iPTH concentrations in overweight and obese, but otherwise healthy adults with vitamin D deficiency, and has no effect on calcium, phosphate and iFGF-23 concentrations and whole-body BMD.

Vitamin D supplementation may improve back pain disability in vitamin D deficient and overweight or obese adults

Back pain is currently the greatest cause of disability worldwide, and there are very limited therapeutic options available. Vitamin D deficiency and obesity are both risk factors for back pain. The few randomised controlled trials examining the effects of vitamin D supplementation on back pain have methodological limitations and largely include non-vitamin D deficient participants. Thus, the aim of this study was to determine whether vitamin D supplementation improves back pain symptoms in vitamin D deficient and overweight or obese, otherwise healthy adults. Sixty-five overweight or obese adults (BMI ≥ 25 kg/m2) with vitamin D deficiency (25-hydroxyvitamin D [25(OH)D] concentrations ≤50 nmol/L) were randomised to a bolus oral dose of 100,000 IU followed by 4000 IU cholecalciferol/day or matching placebo for 16 weeks. We measured 25(OH)D concentrations (chemiluminescent immunoassays) and self-reported back pain (Chronic Pain Grade Questionnaire) before and after the intervention. Lifestyle habits including sun exposure, physical activity, and diet were collected using questionnaires. Fifty-four participants completed the study, of which 49 had complete data for back pain and were included in the present analyses (31 M/18 F; mean ± SD age: 31.8 ± 8.9 years; BMI: 31.1 ± 4.5 kg/m2). After the 16-week intervention, 25(OH)D levels increased significantly with vitamin D supplementation compared with placebo (55.7 ± 20.9 versus 3.9 ± 14.4 nmol/L, respectively, p < 0.001). There were no significant differences between vitamin D and placebo groups in change in back pain intensity or disability scores (all p > 0.05). However, in those with 25(OH)D concentrations <30 nmol/L at baseline (n = 20), there was a significantly greater reduction in back pain disability scores in the vitamin D group compared with placebo, after adjusting for important covariates known to affect vitamin D status and/or back pain (b [95%CI] = -11.6 [-22.4, -0.8], p = 0.04). Our findings suggest that vitamin D supplementation in overweight or obese and markedly vitamin D deficient adults (25(OH)D <30 nmol/L) may improve back pain disability. Although treating severe vitamin D deficiency is recommended for optimising bone health, this study suggests it may also improve back pain. Hence, testing for vitamin D deficiency in those with back pain who are overweight or obese may be warranted.

Pharmacokinetics of florfenicol in turkey plasma, lung tissue, and pulmonary epithelial lining fluid after single oral bolus or continuous administration in the drinking water

Florfenicol (FF) is registered for treatment of bovine and swine respiratory diseases. Although, turkeys often suffer from bacterial respiratory tract infections, there is no registered formulation based on FF for poultry available in Europe. The aim of this study was to evaluate the pharmacokinetic behavior of FF in turkeys in plasma, lung tissue, and pulmonary epithelial lining fluid (PELF).The concentration and pharmacokinetic characteristics of FF in plasma, lung tissue, and PELF in turkeys were determined, either after a single oral bolus (30mg/kg body weight, BW) or during and after continuous drinking water medication (30mg/kg BW/d for 5 d). Plasma, lung tissue, and PELF samples were collected at different intervals after administration, and FF was quantified by liquid chromatography-tandem mass spectrometry. After single bolus administration, FF was rapidly absorbed in plasma (the time to maximum concentration, tmax, was 1.02h) and distributed to the respiratory tract (mean tmax = 1.00h). The mean t1/2el in plasma and lung tissue was similar, around 6h, whereas it was slightly higher in PELF, namely, 8.7hours. After oral bolus dosing, the mean maximum concentration in plasma was twice as high as in the lung tissue, 4.26μg/mL and 2.64μg/g, respectively, while in PELF it was much lower, 0.39μg/mL. During continuous drinking water medication, lung FF concentrations were slightly higher than plasma concentrations, with lung/plasma ratios of 2.01 and 1.27 after 24h and 72h, respectively. FF was not detected in PELF during continuous drinking water medication.

Pharmacological inhibition of the NLRP3 inflammasome as a potential target for multiple sclerosis induced central neuropathic pain.

The NOD-like receptor (NLR) family pyrin domain-containing protein 3 (NLRP3) inflammasome is implicated in the pathogenesis of multiple diseases including neuroinflammation associated with multiple sclerosis (MS). However, the extent to which NLRP3 has a pathobiological role in MS-associated central neuropathic pain (CNP) is unknown. Hence, the present study was designed to address this issue using an optimised relapsing-remitting experimental encephalomyelitis (RR-EAE)-mouse model of MS-associated neuropathic pain. RR-EAE mice with fully developed mechanical allodynia in the bilateral hindpaws (paw withdrawal thresholds (PWTs)≤1g) at day 16 post-immunisation (p.i.) were administered single oral bolus doses of MCC950, a selective and potent small-molecule inhibitor of NLRP3, once daily for 21 consecutive days. Following administration of the first dose of MCC950 at 50 mgkg-1, the mean (±SEM) peak anti-allodynic effect was observed at~1h post-dosing with a duration of action of~2h. Following chronic dosing with MCC950, mechanical allodynia in the bilateral hindpaws was progressively reversed by oral treatment with MCC950 (50 mgkg-1day-1), but not vehicle. Specifically, by day 25 p.i. and continuing until study completion on day 36 p.i., bilateral hindpaw PWTs of RR-EAE mice treated with MCC950 (50 mgkg-1day-1) did not differ significantly (P>0.05) from the corresponding hindpaw PWTs for the sham (control) group. In addition, MCC950 at 50 mgkg-1day-1 attenuated disease relapses in RR-EAE mice indicated by tail limpness as well as hindlimb weakness. Together, our findings suggest that inhibition of NLRP3 inflammasome activation may be a potential therapeutic approach to alleviate MS-associated CNP and disease relapses in patients with RR-MS.

Vitamin D and symptoms of depression in overweight or obese adults: A cross-sectional study and randomized placebo-controlled trial

Recent evidence suggests that vitamin D deficiency may contribute to increased risk of depression. However, previous studies are limited by variability in participant characteristics including vitamin D deficiency status and presence of existing diseases, use of low doses of vitamin D supplementation for short durations, and use of co-interventions or psychotropic drugs. We examined whether 25-hydroxyvitamin D (25(OH)D) concentrations were associated with symptoms of depression, as well as whether vitamin D supplementation reduced symptoms of depression in overweight or obese and vitamin D-deficient, but otherwise healthy adults.Cross-sectional analyses were performed on baseline data from 63 (39M/24F) overweight or obese (body mass index (BMI) ≥25kg/m2) and vitamin D-deficient (25(OH)D ≤50 nmol/l) adults (mean age=31.3±8.5), without clinical depression. Participants were randomized to either a bolus oral dose of 100,000 IU followed by 4000 IU daily of cholecalciferol, or matching placebo for 16 weeks. Interventional analyses were performed on data from 48 participants (30M/18F) who completed the trial. We measured serum 25(OH)D concentrations; anthropometry: BMI, waist-to-hip ratio (WHR), % body fat (dual X-ray absorptiometry); and depressive symptoms using the Beck Depression Inventory (BDI) before and after intervention. Data on dietary vitamin D intake (3-day food record), physical activity (international physical activity questionnaire), and sun exposure habits were collected using questionnaires.At baseline, mean 25(OH)D concentration was 32.9±11.3 nmol/l and total BDI score was 6.6±6.3 (range=0–33). There were no associations between 25(OH)D concentrations and total BDI scores or BDI subscales (all p>0.1). After the 16-week intervention, 25(OH)D concentrations increased in the vitamin D group compared to placebo (56.0±20.8 versus 2.7±13.9 nmol/L, respectively; p <0.0001). Change in total BDI scores did not differ between vitamin D and placebo groups (−2.0±4.5 versus −1.5±2.9, respectively; p=0.7). There were no differences in BDI subscales between groups (both p>0.1). Results remained non-significant after adjusting for multiple covariates including sun exposure, physical activity, and dietary vitamin D intake (all p>0.1).Our findings suggest that vitamin D deficiency may not be related to increased risk of depression in individuals without clinically significant depression and that the use of vitamin D supplementation may not be warranted for reducing depressive symptoms in this population. Further large-scale studies are needed to establish whether vitamin D supplementation may be beneficial for improving depressive symptoms in other population groups, including in those with existing depressive or psychiatric disorders.