Development of a nanoparticle-based system for the delivery of retinoic acid into macrophages

The aim of the present work is to prepare nanoparticulate systems that can target and modulate the functions of mononuclear phagocytes by local administration. All-trans retinoic acid (RA) was chosen as an immunomodulator to be encapsulated in biodegradable nanoparticles (NP). Different formulations were prepared by the nanoprecipitation method and poly(d,l)lactic acid based nanocapsules (NC) were selected to continue the study. RA-NC demonstrated a sustained release profile and an enhanced stability for 7 days. The uptake of fluorescent (NileRed) labeled NP was conducted on bone marrow derived macrophages (BMM) in vitro and xenograft glioma nude mice in vivo. Fluorescent microscopy observations and flow cytometry analysis demonstrated that NR-NC were engulfed by BMM in vitro and lasted inside over 7 days. The intratumoral injection of NR-NC confirmed that NC were efficiently uptaken by infiltrated macrophages. The effects of RA loaded NC on BMM were also evaluated by RT(2)-PCR array. Our results suggest that polymeric nanoparticles are suitable carriers to deliver RA into macrophages and can offer a new strategy in tumor macrophage-based treatment.     

Nano-encapsulation of Vitamin D3 Active Metabolites for Application in Chemotherapy: Formulation Study and in Vitro Evaluation

Purpose

Calcitriol (1,25-dihydroxyvitamin D₃), the active metabolite of vitamin D₃, is a potential anticancer agent but with high risk of hypercalcemia which limits the achievement of effective serum concentrations. Thus, calcitriol targeting delivery by nanoparticles may present a good solution.

Methods

Vitamin D₃ active metabolites were encapsulated into polymeric nanoparticles and different formulation parameters were tested. The growth inhibitory efficiency of these nanoparticles was carried out in vitro on human breast adenocarinoma cells (MCF-7).

Results

Using cholecalciferol (the inactive metabolite), different polymer and oil ratios were compared to select nanoparticles presenting high encapsulation efficiency and sustained release profile. Calcidiol/calcitriol loaded nanoparticles had good encapsulation efficiencies (around 90%) associated with sustained releases over 7 days and enhanced stability. Moreover, loaded nanoparticles showed similar growth inhibition to non-encapsulated metabolites of vitamin D₃ on day 4 and higher activities on days 7 and 10 after treatment initiation.

Conclusion

The nano-encapsulation of vitamin D₃ active metabolites may offer a new and potentially effective strategy for vitamin D₃-based chemotherapy overcoming its actual limitations. The targeting delivery of vitamin D₃ metabolites should be encouraged.     

Maternal–fetal transport and disposition of copper,iron, molybdenum,selenium and zinc in experimentally induced diabetic rats

Objective. To assess maternal–fetal status of essential trace elements such as copper, iron, molybdenum, selenium and zinc, in experimentally induced diabetic and control pregnant rats, and to correlate the findings with those observed in human diabetic pregnancies. Fetal–maternal ratios of the elements and Cu:Zn and Cu:Fe ratios were also computed in control and study groups.

Methods. Diabetes was experimentally induced in pregnant Sprague Dawley rats by injection of streptozotocin. A cocktail of essential trace elements along with antipyrine as internal reference marker were then injected intra-peritoneally to diabetic and matched control pregnant rats on the 20th day of pregnancy. Maternal and fetal blood and tissue samples were collected after sacrificing the animals at 30- and 60-minutes following cocktail injection. Concentrations of trace elements and antipyrine in various blood and tissue samples were then determined by atomic absorption spectrophotometry and colorimetry, respectively.

Results. Concentrations of Cu, Fe, Mo, Se, Zn, and antipyrine averaged 2907.0 ± 212.0 μg/L, 3950.0 ± 766.0 μg/L, 15.8 ± 1.7 μg/L, 74.8 ± 6.5 μg/L, 726.4 ± 67.4 μg/L, and 170.5 ± 8.2 mg/L, respectively, in maternal blood in control pregnant rats (n = 5) at day 20 in the 30-minute study phase, while in the diabetic group (n = 5) the values of the various trace element concentrations and antipyrine averaged 2875.0 ± 225.0 μg/L, 5875.0 ± 688.0 μg/L, 21.2 ± 2.1 μg/L, 116.0 ± 3.6 μg/L, 753.0 ± 71.3 μg/L, and 171.7 ± 4.2 mg/L, respectively. Unpaired student's t-test showed that Fe and Se levels were significantly higher (p < 0.05) in the diabetic pregnant rats compared to controls. Cu, Mo and Zn values, however, were not significantly different (p > 0.05) between the two groups. Cu:Zn and Cu:Fe ratios showed varying differences between maternal and fetal samples in the control and study groups.

Conclusions. Considering the disparity of results in pregnant diabetic rats and pregnant diabetic women, we urge exercising caution when comparing data from animal studies to human situations.     

Maternal–fetal transport kinetics of carboplatin in the perfused human placental lobule: In vitro study

Objective. Platinum-containing drugs are widely used in the treatment of various malignancies in humans. There is a paucity of data on maternal–fetal transport characteristics of one such widely used drug, carboplatin, and this prompted us to study its permeation characteristics in the human placenta in vitro.

Methods. Placentae from uncomplicated, normal pregnancies were collected postpartum. Carboplatin, along with antipyrine as internal reference marker were injected as a single bolus (100 ul) into the maternal arterial circulation of isolated perfused placental lobules and perfusate samples collected from both maternal and fetal circulations over a period of 5 minutes. National Culture and Tissue Collection medium, diluted with Earle's buffered salt solution was used as the perfusate. Carboplatin concentration in various samples was determined by atomic absorption spectrophotometry, while antipyrine concentration was assayed by spectrophotometry. Transport and pharmacokinetic data of study and reference substances were computed using appropriate parameters.

Results. The differential transport rate of carboplatin for 10, 25, 50, 75, and 90% efflux fractions in fetal venous effluent averaged 0.60, 1.35, 2.52, 3.72, and 4.49 minutes in 12 perfusions, representing 1.16 ± 0.10, 1.06 ± 0.06, 1.00 ± 0.02, 0.98 ± 0.01, and 0.99 ± 0.01, respectively, times the antipyrine reference value. Student's t-test did not show any significant difference (p > 0.05) between the control and study group data. The transport fraction (TF) of carboplatin, expressed as the fraction of the drug appearing in the fetal vein during a study period of 5 minutes, averaged 9.00 ± 0.52% of bolus dose, while antipyrine TF averaged 68.60 ± 2.01% of injected bolus dose, representing 13.1% of reference marker value. Student's t-test showed carboplatin and reference marker TF values to be significantly different (p < 0.05). Pharmacokinetic parameters such as area under the curve, clearance, time for maximum response, and absorption and elimination rates of study and reference substances showed varying differences.

Conclusions. We report for the first time that carboplatin transport from the maternal to the fetal circulation is relatively small in the human placenta at term. It is reasonable to assume that the risk for the neonate from carboplatin use in pregnancy is minimal when used in emergency clinical situations.     

Hyperchloremic acidosis increases circulating inflammatory molecules in experimental sepsis

RATIONALE: Hyperchloremic acidosis is common in the critically ill and is often iatrogenic. We have previously shown that hyperchloremic acidosis increases nuclear factor-kappaB DNA binding in lipopolysaccharide-stimulated RAW 264.7 cells. However, evidence that hyperchloremic acidosis leads to increased inflammation in vivo has been limited to nitric oxide. OBJECTIVES: To determine if acidosis, induced by dilute hydrochloric acid (HCl) infusion, will increase circulating inflammatory mediator levels in an experimental model of severe sepsis in rats. METHODS: Eighteen hours after inducing lethal sepsis by cecal ligation and puncture in 20 adult, male, Sprague-Dawley rats, we randomized animals into three groups. In groups 2 and 3, we began an IV infusion of 0.1 N HCl to reduce the standard base excess (SBE) by 5 to 10 mEq/L and 10 to 15 mEq/L, respectively. In group 1, we infused a similar volume of lactated Ringer solution. In all groups infusion continued 8 h or until the animal died. MEASUREMENTS AND MAIN RESULTS: We measured arterial blood gases, whole-blood lactate, and chloride, tumor necrosis factor (TNF), interleukin (IL)-6, and IL-10 levels at 0 h, 4 h, and 8 h. All measured cytokines increased over time. Compared to group 1, animals in groups 2 and 3 exhibited greater increase in all three cytokines, with the greatest increases seen with severe acidosis. CONCLUSION: Moderate (SBE, - 5 to - 10) and severe (SBE, - 10 to - 15) acidosis, induced by HCl infusion, increases circulating levels of IL-6, IL-10, and TNF in normotensive septic rats.     

Pediatric drug formulations of sodium benzoate: II. Coated granules with a lipophilic binder.

Sodium benzoate is used as a therapeutic agent in the treatment of some rare disorders that predominantly affect children. In preliminary investigations, liquid and semi-solid formulations of sodium benzoate failed because children refuse the oral uptake due to the bad taste of the drug. Recently developed microcapsules with macrogol as a hydrophilic binder raise concern in high-dose treatment regimens because acceptable daily intake limits are exceeded. A novel microcapsule formulation was developed consisting of a lipophilic core with high sodium benzoate load and a saliva-resistant coating. A new powder quality of saturated triglycerides from plant origin was introduced which complies with the Ph. Eur. monograph 'Hard fat'. Sodium benzoate and the triglyceride were mixed and directly extruded at room temperature. The extrudates were spheronized and coated in a fluidized-bed process. The resulting coated granules are small-sized microcapsules and taste neutrally. They can be mixed with food before administration. As the amount of released sodium benzoate is negligible within the first minutes, children do not recognize the bad taste and accept the medication. Recently, sodium benzoate in this novel formulation has been designated by the European Community as an orphan drug in the treatment of non-ketotic hyperglycinemia.     

Experiences of torture and ill-treatment and posttraumatic stress disorder symptoms among Palestinian political prisoners

The relationship between the nature and severity of experiences of torture and ill-treatment and posttraumatic stress disorder (PTSD) symptoms was studied in 550 male nonhelp-seeking Palestinian political ex-prisoners from the Gaza Strip. Results showed that the more a prisoner had been exposed to physical, chemical and electric torture, psychological ill-treatment, and sensory deprivation or bombardment, the more he subsequently suffered from intrusive reexperiencing, withdrawal and numbness, and hyperarousal. Existential problems were not related to torture experiences. Furthermore, duration of imprisonment, health problems during the imprisonment, harassment during arrest and after release, family, marriage and economic difficulties all predicted intrusive reexperiences of trauma. Also, ex-prisoners who continued to be harassed by military authorities and had economic problems suffered more from withdrawal, numbness, and hyperarousal than others.     

Electrical stimulation of the cochlear nerve in rats: analysis of c-Fos expression in auditory brainstem nuclei

We investigated functional activation of central auditory brainstem nuclei in response to direct electrical stimulation of the cochlear nerve using c-Fos immunoreactivity as a marker for functional mapping. The cochlear nerve was stimulated in the cerebellopontine angle of Lewis rats applying biphasic electrical pulses (120-250 muA, 5 Hz) for 30 min. In a control group, bilateral cochlectomy was performed in order to assess the basal expression of c-Fos in the auditory brainstem nuclei. The completeness of cochlear ablations and the response of auditory brainstem nuclei to electrical stimulation were electrophysiologically verified. C-Fos immunohistochemistry was performed using the free floating method. In anaesthetized animals with unilateral electrical stimulation of the cochlear nerve, increased expression of c-Fos was detected in the ipsilateral ventral cochlear nucleus (VCN), in the dorsal cochlear nucleus bilaterally (DCN), in the ipsilateral lateral superior olive (LSO) and in the contralateral inferior colliculus (IC). A bilateral slight increase of c-Fos expression in all subdivisions of the lateral lemniscus (LL) did not reach statistical significance. Contralateral inhibition of the nuclei of the trapezoid body (TB) was observed. Our data show that unilateral electrical stimulation of the cochlear nerve leads to increased expression of c-Fos in most auditory brainstem nuclei, similar to monaural auditory stimulation. They also confirm previous studies suggesting inhibitory connections between the cochlear nuclei. C-Fos immunoreactivity mapping is an efficient tool to detect functional changes following direct electrical stimulation of the cochlear nerve on the cellular level. This could be particularly helpful in studies of differential activation of the central auditory system by experimental cochlear and brainstem implants.     

Predictors of duration of postoperative hospital stay in patients undergoing advanced laparoscopic surgery

The expansion of the indications for laparoscopic surgery to include high-risk patient, acute and malignant pathology, and more complex procedures may prolong the hospital stay. Cox multiple stepwise regression analysis model was employed to determine independent predictors of prolonged postoperative hospital stay (more than 3 days) following advanced laparoscopic procedures among 10 variables. Some 130 patients had undergone advanced laparoscopic surgical procedures between November 2000 and August 2003. The median postoperative hospital stay was 3 days (interquartile range 2-5), and 81 patients (62.3%) were discharged within 3 days of surgery. The independent predictors of prolonged postoperative hospital stay were ASA score of 3 or 4 (odds ratio [OR] = 4.610, P = 0.0002) and preoperative hospital stay (OR = 0.151 per day, P = 0.001). Independent predictors of duration of preoperative hospital stay were emergency admission to hospital (OR = 9.516, 95% CI 5.770-13.261, P < 0.0001) and an underlying malignant pathology (OR = 7.948, 95% CI 3.623-12.273, P = 0.0004). Advanced laparoscopic surgery is associated with a short postoperative hospital stay in the majority of patients. Prolongation of the postoperative hospital stay (more than 3 days) may be expected if the patient had been in the hospital with an acute or malignant disease for more than 6 days prior to surgery and in patients with high comorbidity. The duration of surgery has no impact on the duration of the postoperative hospital stay.