Elaboration, morphology and properties of starch/polyester nano-biocomposites based on sepiolite clay

The incorporation of nano-sized sepiolite clays into thermoplastic starch/poly(butylene adipate-co-terephthalate) (TPS/PBAT) blends has been investigated with the goal of improving the matrix properties. TPS/PBAT nano-biocomposites were elaborated with two different proportions of the polymeric phases. The influence of the sepiolite nanoclays on the mechanical, thermal and structural properties of the corresponding blends was evaluated. SEM images confirmed the good dispersion of the sepiolite clay, with a low occurrence of small aggregates in the polymeric matrix. Wide-angle X-ray diffraction showed no significant alteration of the crystalline structures of PBAT and starch induced by the sepiolite clay. The addition of sepiolite slightly affected the thermal degradation of the nano-biocomposites; however, the mechanical tests revealed an increase in some mechanical properties, demonstrating that sepiolite is a promising nanofiller for TPS-based materials.

Nitric oxide is a positive regulator of the Warburg effect in ovarian cancer cells

Ovarian cancer (OVCA) is among the most lethal gynecological cancers leading to high mortality rates among women. Increasing evidence indicate that cancer cells undergo metabolic transformation during tumorigenesis and growth through nutrients and growth factors available in tumor microenvironment. This altered metabolic rewiring further enhances tumor progression. Recent studies have begun to unravel the role of amino acids in the tumor microenvironment on the proliferation of cancer cells. One critically important, yet often overlooked, component to tumor growth is the metabolic reprogramming of nitric oxide (NO) pathways in cancer cells. Multiple lines of evidence support the link between NO and tumor growth in some cancers, including pancreas, breast and ovarian. However, the multifaceted role of NO in the metabolism of OVCA is unclear and direct demonstration of NO's role in modulating OVCA cells' metabolism is lacking. This study aims at indentifying the mechanistic links between NO and OVCA metabolism. We uncover a role of NO in modulating OVCA metabolism: NO positively regulates the Warburg effect, which postulates increased glycolysis along with reduced mitochondrial activity under aerobic conditions in cancer cells. Through both NO synthesis inhibition (using L-arginine deprivation, arginine is a substrate for NO synthase (NOS), which catalyzes NO synthesis; using L-Name, a NOS inhibitor) and NO donor (using DETA-NONOate) analysis, we show that NO not only positively regulates tumor growth but also inhibits mitochondrial respiration in OVCA cells, shifting these cells towards glycolysis to maintain their ATP production. Additionally, NO led to an increase in TCA cycle flux and glutaminolysis, suggesting that NO decreases ROS levels by increasing NADPH and glutathione levels. Our results place NO as a central player in the metabolism of OVCA cells. Understanding the effects of NO on cancer cell metabolism can lead to the development of NO targeting drugs for OVCAs.

Population pharmacokinetics of CNTO 95, a human anti-αv integrin antibody, in patients with solid tumors

e14593

Background: CNTO 95 is a human anti-αv integrin antibody. The dose-dependent antitumor effect of CNTO 95 has been demonstrated in multiple preclinical studies. The objective of these analyses was to characterize the population pharmacokinetics (PPK) in solid tumor cancer patients treated with CNTO 95 with and without dacarbazine. Methods: Approximately 140 patients with solid tumors from two phase I and one phase II studies were included in this analysis. CNTO 95 was administered via intravenous infusion, with 11 different regimens ranging from 0.1 to 20 mg/kg every 1–4 weeks. Serum CNTO 95 concentrations were determined using a validated enzyme-linked immunosorbent assay. Serum CNTO 95 concentration data were analyzed using noncompartmental analysis (NCA) and a PPK approach. Results: The NCA results indicated that total clearance of CNTO 95 decreased as the dose of CNTO95 increased and approached saturation at 10 mg/kg. Based on the NONMEM analysis, data were best described by a 2-compartment model with dual clearance pathways (linear and nonlinear elimination). The nonlinear elimination process is likely due to the receptor-mediated clearance. Mean estimates of central volume, peripheral compartment volume, intercompartmental clearance and linear clearance, as well as an additional nonlinear clearance, were in agreement with antibodies targeting membrane-bound receptors. No differences in the PPK of CNTO 95 were found in patients treated with and without co-administered dacarbazine. Interindividual variability was moderate (<50%). Conclusions: A PPK model could adequately describe serum CNTO 95 concentration-time profiles. Extensions of this model can be used to assist in the selection of doses in diverse oncology patient populations.

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Effects of withdrawal of bracing in matched pairs of children with osteogenesis imperfecta

OBJECTIVES

To evaluate the effects of withdrawal of long-leg braces (hip-knee-ankle-foot orthoses [HKAFO]) on activity and ambulation in children with osteogenesis imperfecta.

DESIGN

A prospective, randomized cross-over trial, that describes the effects of withdrawing HKAFO.

PATIENTS

Ten children who were ambulatory with the assistance of braces. All had type III or IV osteogenesis imperfecta. Children were paired for age and clinical severity. Strength testing, fractures, and independence in daily activity were monitored at 4-month intervals for 32 months (16 months each of braced and unbraced periods). Gait was analyzed during braced and unbraced conditions.

RESULTS

Muscle strength declined .35 grade during unbraced and .1 grade during braced intervals. Children spent more time in upright activity during braced intervals than during unbraced intervals (p = .17). Children were more independent in daily activities during braced than during unbraced periods (p = .14). Seventeen fractures of lower extremities occurred during all the unbraced periods, and 8 occurred during the braced intervals (p = .08); the fracture rate was higher during unbraced intervals. (p = .06) Bracing was associated with increased hip flexion and stride length and decreased transverse plane pelvic rotation.

CONCLUSION

Withdrawal of HKAFO in children with osteogenesis imperfecta who had achieved upright activity was not associated with significant decrease in muscle strength or independence, but there was an associated increase in fracture rate that nearly reached significance.

Use of stable isotopic tracers in studies of whole body calcium metabolism

Stable isotopic tracers of calcium have been used to characterize the absorption of dietary calcium and the subsequent distribution of this element through the body. For a group of 7 healthy children, ages 4-14, and 7 children with osteogenesis imperfecta (OI), types I, III and IV, ages 6-17, there were no detectable differences in the fractional absorption of dietary calcium, 0.29+/-0.11 and 0.28+/-0.16, respectively. The total exchangeable pool of calcium was found to be 161+/-52 mg/kg for the healthy children and 95+/-29 mg/kg for the 3 children with Type I OI, 250+/-75 mg/kg for the 3 children with Type III OI and 216 mg/kg for the child with Type IV OI.

Determination of fractional absorption of dietary calcium in humans

Four dual-isotopic label methods for determining true fractional absorption of dietary calcium were compared in 23 subjects. The ratio of the integrals of oral label in a 24-h pooled urine to intravenous label in the same urine is called alpha 24h and was taken as the standard against which the others were compared. alpha Spot is the ratio of the fraction of oral label to the fraction of intravenous label in a single urine specimen; alpha Lag is the ratio of the level of oral label in blood 4 h after administration to the level of intravenous label in blood 2 h after administration. alpha Dec is obtained by deconvoluting response to the intravenous label from the response to the oral tracer. Results were as follows: alpha 24h = 0.273 +/- 0.124, alpha Dec = 0.300 +/- 0.101 (n = 14), alpha Spot = 0.359 +/- 0.179, and alpha Lag = 0.271 +/- 0.103. The Bland-Altman approach for comparison of methods was used to show that results for alpha Spot and alpha Lag can be expected, with a 95% confidence limit, to differ from the value of alpha 24h by 60 and 69%, respectively. The results for alpha Dec were shown to be not only indistinguishable from alpha 24h but identical from a theoretical perspective.

Comprehensive rehabilitation of the child with osteogenesis imperfecta

Children with osteogenesis imperfecta (OI) that results in considerable deformity are often viewed as poor candidates for aggressive physical therapy and rehabilitation. To determine if this view is realistic, we have entered almost 50 children with OI type III and OI type IV into a comprehensive graduated rehabilitation program, based at the National Institutes of Health, but designed to be implemented by continuing involvement of community resources. Children are begun in the program early with emphasis on gain of head and trunk control and progression to sitting and walking, if possible, with the aid of a variety of physical supports, including internal and external bracing. Although not conducted in a randomized fashion, the program's success in bringing children into graded exercise regimes and fostering their increased involvement in school and social situations suggest that aggressive physical therapy and rehabilitation have a major place in the overall care of the infants and children with OI.

Monoclonal anti-gamma interferon antibodies enhance experimental allergic encephalomyelitis

Interferon-gamma (IFN-gamma) is a cytokine with multiple activities on a variety of cells. Under various circumstances, IFN-gamma can exhibit either pro-inflammatory or inhibitory actions. Treatment of SJL/J mice with a monoclonal antibody (Mab) to IFN-gamma during the afferent limb of the immune response to myelin protein produced an enhancement of acute experimental allergic encephalomyelitis (EAE), with increased morbidity, mortality and earlier onset of disease. Systemic administration of IFN-gamma did not improve or worsen clinical outcome, but delayed disease onset. Passive transfer of immune lymph node cells co-activated with MBP and anti-IFN-gamma Mab resulted in more sever disease than that induced by MBP stimulated cells or MBP and IFN-gamma co-stimulated cells. However, in vitro proliferation of an MBP specific T cell line was not influenced by IFN-gamma nor anti-IFN-gamma treatment. Mab to IFN-gamma inhibited suppressor function, in a non-specific assay. These in vivo and in vitro results suggest that systemic IFN-gamma serves as a physiological regulator of a suppressor mechanism in EAE. The abrogation of this regulatory mechanism by anti-IFN-gamma administration contributes to a more severe form of experimental allergic encephalomyelitis.

Rehabilitation of children and infants with osteogenesis imperfecta. A program for ambulation

Management of children and infants with osteogenesis imperfecta (OI) poses difficult decisions for pediatricians, orthopedists, and physiatrists. These children are frequently frail with disabling bone and joint deformities and fractures. In an eight-year cumulative management of 12 children with OI, a comprehensive program included strengthening exercises to the pelvic girdle and lower extremity muscles, in addition to pool exercises and molded seating to support upright posture. Long leg braces were fitted when the children were able to sit unsupported. All 12 were fitted with braces; nine were functional ambulators, and three were home ambulators. Six children required femoral plating or rodding, two of whom subsequently had the metal removed. Lower extremity fractures averaged one and one-half per year prior to bracing for nine children who had fractures. There was 0.83 fracture per year for the ten children who had fractures after bracing. The degree of femoral bowing increased in four, decreased in four, and remained unchanged in four, while the degree of tibial bowing increased in two, decreased in nine, and remained unchanged in one during the observation period. A comprehensive rehabilitation program and long leg bracing with surgical operations on the femur result in a high level of functional activity for children with OI with an acceptable level of risk for fracture.

A role for the medial region of the amygdala in mineralocorticoid-induced salt hunger

Damage to the medial region of the amygdala abolished aldosterone-induced salt hunger in the rat. In contrast, the salt hungers that are induced by adrenalectomy or by acute sodium depletion are left intact by the same brain damage. We suggest (a) that we have identified part of the neural circuit by which aldosterone participates in the genesis of salt hunger in the intact, sodium-depleted rat and (b) that these results provide further evidence for the hypothesis that there are separate receptive systems in the brain for the participation of aldosterone and angiotensin in the arousal of salt hunger.

Fibrodysplasia ossificans progressiva: CT appearance

Twelve patients with fibrodysplasia ossificans progressiva were studied with computed tomography (CT). Characteristic swelling of the muscular fascial planes could be identified on CT scans prior to the development of ectopic ossification. Ossification could be seen on CT scans before it was apparent on plain radiographs. The pattern of ossification was similar to that seen at pathologic study, with multifocal sites developing adjacent to and extending around muscles. The appearance on CT scans confirms the hypothesis that the initial focus in fibrodysplasia ossificans progressiva is in the connective tissue.

Technetium-99m MDP demonstration of heterotopic ossification in fibrodysplasia ossificans progressiva

The extensive heterotopic bone formation in patients with fibrodysplasia ossificans progressiva (FOP) has been documented previously with radiographs. A case in which a Tc-99m MDP bone scan showed increased uptake at sites well before ossification could be documented radiographically is described. This finding suggests that bone scans would likely be useful to monitor the extent of involvement with FOP and to detect areas of new activity.

Effect of anesthetic doses of gamma-hydroxybutyrate on the acetylcholine content of rat brain

Gamma-hydroxybutyrate administered in anesthetic doses produces a time dependent increase in the levels of rat barin acetylcholine. A maximal increase in whole brain and subcortical levels of acetylcholine is observed about 15 min after administration of the lactone form of the drug. A similar GHB-induced increase in acetylcholine is observed in the striatum and a 75% increase in the hippocampus 15 min after administration of the drug. A good temporal correlation was not obtained between the increase in acetylcholine and the depth of anesthesia produced by the drug. Gamma-hydroxybutyrate did not cause a significant change in the striatal or hippocampal levels of choline. Possible mechanisms involved in the production of this increase in acetylcholine are discussed.