Comparison of the intestinal absorption and bioavailability of γ-tocotrienol and α-tocopherol: in vitro, in situ and in vivo studies

The aim of this work was to compare the intestinal absorption kinetics and the bioavailability of γ-tocotrienol (γ-T3) and α-tocopherol (α-Tph) administered separately as oil solutions to rats in vivo. Also, to explain the significant difference in the oral bioavailability of the compounds: (1) the release profiles using the dynamic in vitro lipolysis model, (2) the intestinal permeability and (3) carrier-mediated uptake by Niemann-Pick C1-like 1 (NPC1L1) transporter were examined. Absolute bioavailability studies were conducted after oral administration of γ-T3 or α-Tph prepared in corn oil to rats. In situ rat intestinal perfusion with ezetimibe (a NPC1L1 inhibitor) was performed to compare intestinal permeability. The in vitro interaction kinetics with NPC1L1 was examined in NPC1L1 transfected cells. While the in vitro release studies demonstrated a significantly higher release rate of γ-T3 in the aqueous phase, the oral bioavailability of α-Tph (36%) was significantly higher than γ-T3 (9%). Consequent in situ studies revealed significantly higher intestinal permeability for α-Tph compared with γ-T3 in rats. Moreover, the NPC1L1 kinetic studies demonstrated higher Vmax and Km values for α-Tph compared with γ-T3. Collectively, these results indicate that intestinal permeability is the main contributing factor for the higher bioavailability of α-Tph. Also, these results emphasize the potentially important role of intestinal permeability in the bioavailability of γ-T3, suggesting that enhancing its permeability would increase its oral bioavailability.     

Comparison of the in vitro binding characteristics of the β-carbolines harman and norharman in rat brain and liver and in bovine adrenal medulla

The in vitro binding of the naturally occurring -carbolines harman and norharman in their tritium-labelled forms to cell membranes from the rat brain and liver and from bovine adrenal medulla was investigated. Displacement of the specific [³H]harman binding in bovine adrenal medulla and rat liver by several -carbolines and monoamine oxidase (MAO) inhibitors revealed the pharmacological profile of a single, high-affinity binding site (K _D 4.92±0.43 nmol/l, B_max 8.47±0.17 pmol/mg protein; adrenal medulla) which corresponded to the active site of MAO type A (MAO-A). Similar characteristics have previously been found for brain tissue from rat, marmoset and pig. In order to determine the temperature dependence of the [³H]harman binding, the K _D and B_max values for rat cerebral cortex were calculated from the results of saturation experiments at 5 temperatures (range: 0°C–37°C). Whereas the B_max values under all conditions were – 4 pmol/mg protein, the K _D values, with increasing temperature, ranged from 3 nmol/l to 30 nmol/l. The calculated linear van't Hoff plot (-In K _D against 1/T) suggested an enthalpy-driven binding of [³H]harman to MAO-A.At least three different [³H]norharman-binding sites were detected. In the rat forebrain, 85% of the specific binding (at about 2 nmol/l of [³H]norharman) can be attributed to a MAO binding site of type B: the binding is displaceable, in nmol/l concentrations by the potent and selective MAO-B inhibitors MDL 72,974A, R(–)-deprenyl and pargyline and, in mol/l concentrations, by S(+)-deprenyl and the potent and selective MAO-A inhibitors clorgyline, harmine, harman, harmaline, brofaromine 5-F--methyltryptamine. After suppression of the MAO binding sites with 1 mol/l clorgyline and mol/l R(–)-deprenyl, a second binding site was found. However, the binding at this site was biphasically displaceable by harman and norharman (Hill-slopes about 0.5 and 0.6, curvilinear Rosenthal plots) suggesting the presence of negative co-operativity or of two binding sites (states). A similar clorgyline/R(–)-deprenyl resistent single (Hill-slopes of displacement by norharman, harman and 6-hydroxy--carboline about unity; linear Rosenthal plots) high affinity binding site (K _D 7.5±2 nmol/l, B_max 130±30 fmol/mg protein) was found in bovine adrenal medullary cell membranes. A third quite different clorgyline/R(–)-deprenyl resistent high-affinity (K _D14 nmol/l) and high-density (B_max 10–30 pmol/mg protein) binding site was detected in the liver. The specific binding at this site was not displaceable by harman or most other substituted -carbolines or by tetrahydro--carbolines, but was displaced by norharman and several newly synthesized 6-substituted aromatic -carbolines (e.g. F-, CH₃-, CH₃O-, HO-). The [³H]norharman binding site in the liver is certainly not identical with any of the binding sites for MAO-inhibitors, benzodiazepines or sigma receptor ligands and is slightly enriched in the microsomal (P₃) fraction whereas most of the specific [³H]harman binding was detected in the crude mitochondrial (P₂) fraction. Correspondence to: T. May at the above address     

Bioavailability and disposition of ‘H-solanine in rat and hamster

1. The toxicokinetics of [³H]-α-solanine after oral (p.o.) and intravenous (i.v.) administration in rat and hamster were studied, in order to decide which is the most appropriate model in risk assessment studies. The i.v. Dose was 54 βg/kg; the oral dose was 170 βg/kg.

2. After i.v. Administration, the toxicokinetics of total radioactivity in blood were comparable in rat and hamster. However, the clearance of total radioactivity from plasma was more effective in rat than in hamster. The half-lives of distribution and of the terminal phase of unchanged α-solanine were not different between rat and hamster, whereas the systemic and metabolic clearance were, respectively, about 1.6 and 2.7 times higher in rat than in hamster. The clearance of unchanged α-solanine is more effective than of total radioactivity.

3. After p.o. Administration in rat and hamster, the mean bioavailability of total radioactivity is about 29 and 57%, respectively. The bioavailability of unchanged α-solanine is only 1.6 and 3.2%, respectively, when compared with i.v. administration.

4. T_1/2el of α-solanine after p.o. Administration was in rats a factor of four and in hamsters a factor of two shorter than after i.v. Administration. A strong retention of radioactivity was seen in the hamsters after p.o. Administration; only 40% of the dose was excreted within 7 days versus 90% in rat.

5. Based on these and toxicological data from literature, it was decided that the hamster is a more appropriate model in (sub) chronic toxicity studies with α-solanine than the rat.     

Detection and quantitation of β-blockers in plasma and urine

β-blockers are a class of antihypertensive drugs that are used for the management of cardiac arrhythmias, cardioprotection after myocardial infarction (heart attack) and hypertension. They have revolutionized the medical management of angina pectoris and are recommended as first-line agents by national and international guidelines. Although β-blockers are still the cornerstone for the treatment of heart failure, some of the drugs in this category are prohibited in several sports requiring vehicle control and bodily movements as they reduce heart rate and tremors, and improve performance. As a result, urine analysis of β-blockers is mandatory in doping control and toxicological screening. The determination of plasma levels of β-blockers helps to ensure noncompliance in patients with persistent hypertonia to confirm the diagnosis of β-blocker poisoning and for therapeutic drug monitoring. This review provides a comprehensive account of various analytical methods developed for detection and quantitation of β-blockers in plasma and urine.     

Effect of lactoferrin- and transferrin-conjugated polymersomes in brain targeting： in vitro and in vivo evaluations

Aim:

To evaluate the effect of lactoferrin (Lf) and transferrin (Tf) in brain targeting.

Methods:

Polymersomes (PSs), employed as vectors, were conjugated with Lf or Tf and were characterized by morphology, particle size, zeta potential, and surface densities of the Lf or Tf molecules. In vitro uptake of Lf-PS and Tf-PS by bEnd.3 cells was investigated using coumarin-6 as a fluorescent probe. In vivo tissue distribution and pharmacokinetics of ¹²⁵I-Lf-PS and ¹²⁵I-Tf-PS were also examined.

Results:

The mean particle size of PS, Lf-PS, and Tf-PS was around 150 nm and the zeta potential of the PSs was about -20 mV. Less than 0.12% of the coumarin was released from coumarin-6-loaded PS in 84 h indicating that coumarin-6 was an accurate probe for the PSs'' behavior in vitro. It was shown that the uptake of Lf-PS and Tf-PS by bEnd.3 cells was time-, temperature-, and concentration-dependent. Both Lf and Tf could increase the cell uptake of PSs at 37°C, but the uptake of Tf-PS was significantly greater than that of Lf-PS. In vivo tissue distribution and pharmacokinetics in mice revealed higher brain uptake and distribution of Tf-PS than Lf-PS, which was in accordance with in vitro uptake results. The drug targeting index (DTI) of Tf-PS with regard to Lf-PS was 1.51.

Conclusion:

Using a PS as the delivery vector and bEnd.3 cells as the model of the blood-brain barrier (BBB), Tf was more effective than Lf in brain targeting.     

Formulation and optimization of alkaline extracted ispaghula husk microparticles of isoniazid – in vitro and in vivo assessment

Microparticles containing isoniazid were prepared by the emulsification internal ionic gelation method using a novel, alkaline extracted ispaghula husk as a wall forming material. A four-factor three-level Box–Behnken design was employed to study the effect of independent variables on dependent variables. Sodium alginate concentration (X₁), alkaline extraction of ispaghula husk (AEISP) concentration (X₂), concentration of cross-linking agents (X₃) and stirring speed (X₄) were four independent variables considered in the preparation of microparticles, while the particle size (Y₁) and entrapment efficiency (Y₂) were dependent variables. Optimized microparticles exhibited 83.43% drug entrapment and 51.53?µm particle size with 97.80% and 96.37% validity, respectively, at the following conditions – sodium alginate (3.55% w/v), alkaline extracted ispaghula husk (3.60% w/v), cross-linker concentration (7.82% w/v) and stirring speed (1200?rpm). The optimized formulation showed controlled drug release for more than 12?h by following Higuchi kinetics via non-Fickian diffusion. The gamma scintigraphy of the optimized formulation in Wistar rats showed that microparticles could be observed in the intestinal lumen after 1?h and were detectable in the intestine up to 12?h, with decreased percentage of radioactivity (t_1/2 of ^99mTc 4–5?h).     

Risk–benefit of antiemetics in prevention and treatment of chemotherapy-induced nausea and vomiting

The development of effective antiemetic prophylaxis is one of the most significant steps forward in the area of supportive care. Fifteen years ago, patients receiving chemotherapy had to face the fact that nausea and vomiting were inevitable adverse effects, which could only be partially prevented by treatment with antiemetics such as dopamine (DA) D2 receptor antagonists and corticosteroids. The first group of drugs specifically developed as antiemetics was the serotonin (5-hydroxytryptamine [5-HT]₃) receptor antagonists. These drugs have dramatically improved prophylaxis of chemotherapy-induced emesis, particularly when used in combination with a corticosteroid. This combination has resulted in a significant decrease in the number of patients vomiting, whereas the improvement in the prophylaxis of nausea has been less successful. Another group of antiemetics, the neurokinin (NK)₁ receptor antagonists, has recently been developed, and the first drug in this class, aprepitant, has been approved by the FDA and the EU authorities. Studies have showed that patients benefit from the use of this drug in combination with standard antiemetic therapy (5-HT₃ receptor antagonist plus a corticosteroid), both in the acute and delayed phase of nausea and vomiting induced by cisplatin-based chemotherapy. This development has not only led to improved efficacy but also to a decreased risk associated with the use of antiemetics. One of the problems with traditional antiemetics, for example, the DA D2 receptor antagonists, is the risk of unpleasant adverse effects including restlessness and dystonic reactions. To avoid these adverse effects, combination with benzodiazepines or antihistamines was necessary, often resulting in sedation. Modern research also includes pharmacogenomic investigations. This has led to speculation about the importance of drug–drug interactions involving antiemetics through competition for metabolism by the cytochrome P450 isoenzymes. The worst possible interaction would be a decrease in the effect of different cytotoxins but there is no evidence that such interactions are of importance in daily clinical practice. Guidelines are useful tools in the optimisation of antiemetic prophylaxis but, unfortunately, implementation of the evidence-based recommendations is far from successful. A prerequisite for further optimisation of antiemetic prophylaxis is updating of the guidelines, including recommendations for the use of NK₁ receptor antagonists (aprepitant), followed by implementation of these recommendations in the clinic. Future research must include ‘the difficult trials’ focusing on the remaining groups of patients with severe chemotherapy-induced nausea and vomiting, including patients with refractory and breakthrough emesis.     

Cardioprotective effects of an active metabolite of furnidipine in 2 models of isolated heart and on in vivo ischemia–induced and reperfusion-induced arrhythmias in rats

Dihydropyridines are known not only to have antiarrhythmic effects but also to exert a significant cardiac depressive influence. We previously showed that M-2, an active and final metabolite of furnidipine, had cardioprotective effects without the marked cardiac depression seen with this dihydropyridine. We studied the influence of M-2 infusion (10(-7) M) on hemodynamics during low-flow and regional ischemia in the rat working heart. We examined the protection conferred by M-2 infusion (10(-7) M) against effects of veratridine-induced intracellular calcium overload in the Langendorff heart. Additionally, we performed an in vivo study to explore the effects of oral administration of M-2 at different times and doses, in the ischemia- and reperfusion-induced arrhythmias model. M-2 improved coronary flow during low-flow and regional ischemia while favorably maintaining aortic pressure parameters. M-2 provided outstanding protection against deleterious effects of calcium overloading by significantly preventing rise in left ventricular diastolic pressure and decrease in coronary flow. M-2 reduced mortality and incidence and duration of severe arrhythmias while exhibiting differential influence on blood pressure, which depended on dose and time of administration and could suggest its clinical indication. The results of our entire study establish a beneficial cardioprotective role of M-2, which exhibited pleiotropic effects on the ischemic heart by imparting protection in various ways. This combined with good tolerance, long duration of action, low toxicity, and relatively large therapeutic window makes M-2 a promising candidate as a precursor for a new chemical class of cardioprotective drugs.     

Combination of α-glucosidase inhibitor and ribavirin for the treatment of dengue virus infection in vitro and in vivo

Cellular α-glucosidases I and II are enzymes that sequentially trim the three terminal glucoses in the N-linked oligosaccharides of viral envelope glycoproteins. This process is essential for the proper folding of viral glycoproteins and subsequent assembly of many enveloped viruses, including dengue virus (DENV). Imino sugars are substrate mimics of α-glucosidases I and II. In this report, we show that two oxygenated alkyl imino sugar derivatives, CM-9-78 and CM-10-18, are potent inhibitors of both α-glucosidases I and II in vitro and in treated animals, and efficiently inhibit DENV infection of cultured human cells. Pharmacokinetic studies reveal that both compounds are well tolerated at doses up to 100mg/kg in rats and have favorable pharmacokinetic properties and bioavailability in mice. Moreover, we showed that oral administration of either CM-9-78 or CM-10-18 reduces the peak viremia of DENV in mice. Interestingly, while treatment of DENV infected mice with ribavirin alone did not reduce the viremia, combination therapy of ribavirin with sub-effective dose of CM-10-18 demonstrated a significantly enhanced antiviral activity, as indicated by a profound reduction of the viremia. Our findings thus suggest that combination therapy of two broad-spectrum antiviral agents may provide a practically useful approach for the treatment of DENV infection.     

Different roles of PKC and PKA in effect of interferon-y on proliferation and collagen synthesis of fibroblasts

AIM: To study the signal roles of protein kinase C (PKC) and protein kinase A (PKA) in the influence of interferon-γ(IFN-γ) on proliferation and collagen synthesis of flbroblasts derived from hypertrophic scar (HS-FB) and normal skin (NS-FB). METHODS: HS-FB and NS-FB were cultured and passaged in Dulbecco's modified Eagle's medium (DMEM). Activity of PKC and PKA were assayed by transferring phosphorus (32P) into substrate after treatment with IFN-γ1000 kU/L at 10, 30, 60, and 120 min. Cell proliferation was determined with MTT assay. The collagen synthesis was measured with [3H]proline incorporation and Type Ⅲ pre-collagen was determined with radioimmunoassay. RESULTS: After exposure to IFN-γ1000 kU/L for 30 min, PKC activity of HS-FB and NS-FB increased from 2.57±0.14 and 2.13±0.12 nmol·min-1·g-1 of control to 3.75±0.19 and 3.36±0.16 nmol·min-1·g-1 respectively (P<0.05). After exposure to IFN-y 1000 kU/L for 60 and 120 min, PKA activities of HS-FB increased gradually from 0.82±0.04 nmol·m     

Expression and significance of IGF-Ⅱand VEGF in hepatocellular carcinoma

目的 检测肝癌(HCC)患者组织中IGF-Ⅱ、血管内皮生长因子 (VEGF)的表达及临床意义.方法 采用免疫组织化学染色方法 检测HCC及癌旁组织中IGF-Ⅱ、VEGF蛋白表达水平.结果 HCC及癌旁组织IGF-Ⅱ蛋白阳性表达率分别为55%(22/40)、12.5%(5/40),VEGF蛋白阳性表达率分别为62.5%(25/40)、12.5%(5/40),HCC组织中IGF-Ⅱ、VEGF蛋白表达均显著高于癌旁组织(P<0.05),且IGF-Ⅱ、VEGF表达呈明显正相关(r=0.59,P<0.05).IGF-Ⅱ、VEGF表达与患者的年龄、性别、肿瘤大小无关,但与肿瘤的组织学分级、是否侵及包膜及有无癌栓密切相关.结论 与癌旁组织比较,HCC组织中IGF-Ⅱ、VEGF呈现高表达,提示IGF-Ⅱ、VEGF参与了HCC的发生发展过程,可能与HCC的生长和增殖有关.     

Effects of annexins II and V on survival of neurons and astrocytes in υitro

INTRODUCTIONAnnexins are a family of structurally and func-tionally related proteins that exhibit Ca2 -dependent bind-ing to phospholipids[1-4]. Previous studies suggest thatthese proteins play a role in the development of the cen-tral nervous system (CNS)[5]. In some pathologicalconditions such as traumatic hemorrhage, embolism,and thrombotic infarction[6] or some diseases of the CNSsuch as encephalomyelitis and Alzheimers disease[7],annexin expressions are upregulated. During deve…     

Pharmacokinetic–Pharmacodynamic Modeling of the Effectiveness and Safety of Buprenorphine and Fentanyl in Rats

Objective Respiratory depression is a serious and potentially life-threatening side-effect of opioid therapy. The objective of this investigation was to characterize the relationship between buprenorphine or fentanyl exposure and the effectiveness and safety outcome in rats. Methods Data on the time course of the antinociceptive and respiratory depressant effect were analyzed on the basis of population logistic regression PK–PD models using non-linear mixed effects modeling software (NONMEM). The pharmacokinetics of buprenorphine and fentanyl were described by a three- and two-compartment model, respectively. A logistic regression model (linear logit model) was used to characterize the relationship between drug exposure and the binary effectiveness and safety outcome. Results For buprenorphine, the odds ratios (OR) were 28.5 (95% CI, 6.9–50.1) and 2.10 (95% CI, 0.71–3.49) for the antinociceptive and respiratory depressant effect, respectively. For fentanyl these odds ratios were 3.03 (95% CI, 1.87–4.21) and 2.54 (95% CI, 1.26–3.82), respectively. Conclusion The calculated safety index (OR_{antinociception}/OR_{respiratory depression}) for fentanyl of 1.20 suggests that fentanyl has a low safety margin, implicating that fentanyl needs to be titrated with caution. For buprenorphine the safety index is 13.54 suggesting that buprenorphine is a relatively safe opioid.     

Correlation of the intrinsic clearance of donepezil (Aricept®) between in vivo and in vitro studies in rat,dog and human

1. Donepezil hydrochloride (Aricept®) is used for the treatment of Alzheimer's disease. Here the correlation of the intrinsic clearance (Cl_int) of donepezil between the in vivo and in vitro states was studied in rat, dog and human. 2. In an experiment with ¹⁴C-donepezil and human microsomes the routes of metabolism were identified as N-dealkylation and O-demethylation, and no unknown metabolites were detected. 3. The Cl_int of donepezil in the male rat, female rat, dog and human liver microsomes were 33.7, 13.4, 37.0 and 6.35 μl/min/mg microsomal protein respectively, and sex difference in rat and interspecies difference in the estimated Cl_int were found. 4. After a single intravenous administration to the male rat, female rat and dog, total plasma clearance (Cl^P_total) was 78.6, 29.5 and 88.3 ml/min/kg respectively, and a sex difference was observed in rat. 5. After a single oral administration to the male rat, dog and healthy volunteer, Cl^P_total/F was 140, 105 and 2.35 ml/min/kg respectively, and remarkable differences were observed between animals and man. 6. The contribution of renal clearance to blood clearance (Cl_r) was low in all species. The predicted in vitro hepatic clearance (Cl_h-pre) was in the rank order: male rat (15.91 ml/min/kg) &gt; dog (7.96) &gt; female rat (7.67) &gt; human (1.04). Although Cl_h-pre was underestimated, Cl_h-pre was significantly correlated with that of ClBtotal in the different animal species and in man, indicating that the in vitro-in vivo ranking order was conserved.     

Effect of catecholamic acid on detoxication and distribution of NiCl_2 in mice and rats

目的：研究双酚胺酸（ＣＢＭＩＤＡ）对氯化镍的解毒作用．方法：ＮｉＣｌ２中毒后，立即给予ＣＢＭＩＤＡ，记录动物存活数；小鼠ｉｖ６３ＮｉＣｌ２后给药，测定２４ｈ组织中６３镍；用整体放射自显影术，显示小鼠体内６３镍分布．结果：ｓｃＣＢＭＩＤＡ０５－１５ｇ·ｋｇ－１对ｉｐＮｉＣｌ２５００ｍｇ·ｋｇ－１有解毒作用；小鼠ｉｐＮｉＣｌ２ＬＤ５０为８２８ｍｇ·ｋｇ－１，给药１５或２５ｇ·ｋｇ－１，ＬＤ５０分别为７８９和８２０ｍｇ·ｋｇ－１；大鼠ｉｍＣＢＭＩＤＡ５００ｍｇ·ｋｇ－１使ＮｉＣｌ２的ＬＤ５０提高８倍；组织中６３镍测定和定位显示，ＣＢＭＩＤＡ减少肺和血液中６３镍，增加了骨中６３镍，２４ｈ尿、粪６３镍排出与对照组无明显差异．结论：ＣＢＭＩＤＡ有效地解除镍毒性，提高动物存活率，降低镍在肺部的滞留．     

Formulation and optimization of alkaline extracted ispaghula husk microparticles of isoniazid - in vitro and in vivo assessment

Microparticles containing isoniazid were prepared by the emulsification internal ionic gelation method using a novel, alkaline extracted ispaghula husk as a wall forming material. A four-factor three-level Box-Behnken design was employed to study the effect of independent variables on dependent variables. Sodium alginate concentration (X(1)), alkaline extraction of ispaghula husk (AEISP) concentration (X(2)), concentration of cross-linking agents (X(3)) and stirring speed (X(4)) were four independent variables considered in the preparation of microparticles, while the particle size (Y(1)) and entrapment efficiency (Y(2)) were dependent variables. Optimized microparticles exhibited 83.43% drug entrapment and 51.53?μm particle size with 97.80% and 96.37% validity, respectively, at the following conditions - sodium alginate (3.55% w/v), alkaline extracted ispaghula husk (3.60% w/v), cross-linker concentration (7.82% w/v) and stirring speed (1200?rpm). The optimized formulation showed controlled drug release for more than 12?h by following Higuchi kinetics via non-Fickian diffusion. The gamma scintigraphy of the optimized formulation in Wistar rats showed that microparticles could be observed in the intestinal lumen after 1?h and were detectable in the intestine up to 12?h, with decreased percentage of radioactivity (t(1/2) of (99m)Tc 4-5?h).     

Evaluation of sigma (σ) receptors in the antidepressant-like effects of ketamine in vitro and in vivo

Ketamine is an NMDA antagonist and dissociative anesthetic that has been shown to display rapid acting and prolonged antidepressant activity in small-scale human clinical trials. Ketamine also binds to σ receptors, which are believed to be protein targets for a potential new class of antidepressant medications. The purpose of this study was to determine the involvement of σ receptors in the antidepressant-like actions of ketamine. Competition binding assays were performed to assess the affinity of ketamine for σ(1) and σ(2) receptors. The antidepressant-like effects of ketamine were assessed in vitro using a neurite outgrowth model and PC12 cells, and in vivo using the forced swim test. The σ receptor antagonists, NE-100 and BD1047, were evaluated in conjunction with ketamine in these assays to determine the involvement of σ receptors in the antidepressant-like effects of ketamine. Ketamine bound to both σ(1) and σ(2) receptors with μM affinities. Additionally, ketamine potentiated NGF-induced neurite outgrowth in PC12 cells and this effect was attenuated in the presence of NE-100. Ketamine also displayed antidepressant-like effects in the forced swim test; however, these effects were not attenuated by pretreatment with NE-100 or BD1047. Taken together, these data suggest that σ receptor-mediated neuronal remodeling may contribute to the antidepressant effects of ketamine.     

A comparative study of the role of crocin and sitagliptin in attenuation of STZ-induced diabetes mellitus and the associated inflammatory and apoptotic changes in pancreatic β-islets

Type 1 diabetes mellitus (T1DM) describes a complex group of metabolic disorders associated with elevated blood glucose levels and increased risks of complications development. Exploring new drug therapies would reduce the increased diabetes-associated morbidity and mortality and will reduce the excessive health care costs. Crocin is the major active ingredient of saffron. In the current study, DM was induced by single intraperitoneal injection of streptozocin (50 mg/kg).DM progression was associated with a significant increase in blood glucose level with reduced insulin and increased glucagon secretion. Pancreatic malondialdehyde (MDA) content significantly escalated, while superoxide dismutase (SOD) activity, reduced glutathione (GSH) concentration, catalase activity, thioredoxin level and serum total antioxidant capacity significantly declined. This was associated with a significant increase in pancreatic caspase-3 contents and pancreatic infiltration with inflammatory cells in β-islets. Both sitagliptin and crocin significantly reduced blood glucose levels, enhanced pancreatic insulin expression and secretion and suppressed glucagon secretion with enhancement of anti-oxidant defenses and reduction of oxidative burden, with evident anti-inflammatory impacts. Interestingly, the effect of crocin on DM indices, inflammatory and apoptotic changes was comparable to that of sitagliptin; the standard oral hypoglycemic agent. Nevertheless, crocin had a superior effect compared to sitagliptin on blood sugar level, β-islets diameter and insulin immune-reactivity. In conclusion, crocin reduced blood glucose level mainly via reduction of oxidative burden, modulation of apoptotic pathway and attenuation of pancreatic inflammation.     

Hypoxia-mediated down-regulation of OCTN2 and PPARα expression in human placentas and in BeWo cells

The objective of the present study was to investigate the effects of hypoxia on placental expression of OCTN2 and PPARα. OCTN2 and PPARα expression in the human placenta in the presence or absence of preeclampsia was examined by immunohistochemical (IHC) analysis, Western blotting, and quantitative polymerase chain reaction (qPCR). Effects of hypoxia on the expression of OCTN2 and PPARα in human placental explants and human choriocarcinoma BeWo cells were examined by Western blotting and qPCR analyses. IHC, Western blot, and qPCR studies showed that OCTN2 and PPARα protein and mRNA levels were lower in syncytiotrophoblasts from preeclamptic human placentas than in those from normal placentas. Hypoxic treatment caused a decrease in OCTN2 and PPARα expression in human placental explants and in BeWo cells. WY14643, a PPARα agonist, caused an increase in OCTN2 expression in BeWo cells under hypoxic conditions. In conclusion, under hypoxic conditions, placental OCTN2 is down-regulated through PPARα-mediated pathways.