Nanoparticles for skin penetration enhancement--a comparison of a dendritic core-multishell-nanotransporter and solid lipid nanoparticles

Nanosized particles are of growing interest for topical treatment of skin diseases to increase skin penetration of drugs and to reduce side effects. Effects of the particle structure and size were studied loading nile red to dendritic core-multishell (CMS) nanotransporters (20-30 nm) and solid lipid nanoparticles (SLNs, 150-170 nm). Interaction properties of CMS nanotransporters with the dye molecules--attachment to the carrier surface or incorporation in the carrier matrix--were studied by UV/Vis and parelectric spectroscopy. Pig skin penetration was studied ex vivo using a cream for reference. Interactions of SLN and skin were followed by scanning electron microscopy, internalisation of the particles by viable keratinocytes by laser scanning microscopy. Incorporating nile red into a stable dendritic nanoparticle matrix, dye amounts increased eightfold in the stratum corneum and 13-fold in the epidermis compared to the cream. Despite SLN degradation at the stratum corneum surface, SLN enhanced skin penetration less efficiently (3.8- and 6.3-fold). Viable human keratinocytes showed an internalisation of both nanocarriers. In conclusion, CMS nanotransporters can favour the penetration of a model dye into the skin even more than SLN which may reflect size effects.     

α-Lactalbumin-enriched low-protein infant formulas: a comparison to breast milk feeding

Tryptophan (TRP) is the limiting amino acid in low-protein infant formulas. This is mainly due to lower α-lactalbumin (αLA) content in cow's milk whey as compared with human milk protein. To study the effect of αLA-enrichment on the TRP supply, cross-over studies were carried out in 20 healthy infants up to 3 months of age. In this study, two protein-reduced (1.3%) infant formulas (moderate TRP content of 1.88% and higher TRP content of 2.10%) were alternately fed over a 2 week period in two groups of infants. Serum TRP levels of the formula-fed infants with the higher TRP content did not differ significantly from an exclusively breastfed control group of 11 infants (10.5 ±4.8 versus 10.9±4.7mgl^-1, p = 0.841), whereas levels of the formula-fed infants with the moderate TRP content were significantly lower (7.4 ± 3.9, p = 0.038). The supplementation of αLA resulting in a higher TRP supply to low-protein diets is a further step towards the production of infant formulas more closely adapted to human breast milk.     

DETERMINANTS OF THE KINETICS OF VERY LOW-DENSITY LIPOPROTEIN APOLIPOPROTEIN B-100 IN NON-OBESE MEN

1. Apolipoprotein B-100 (ApoB) is the principal structural and functional protein of the pro-atherogenic lipoproteins. Elevated plasma apoB is an independent risk factor for coronary artery disease. In the present study we aimed to assess the factors that determine the kinetics of apoB in the very low-density lipoprotein (VLDL) in healthy men. 2. We studied 17 non-obese men who were consuming an ad libitum diet and had the following characteristics: mean (± SD) age 45.5 ± 9.7 years, body mass index (BMI) 25.1 ± 1.4 kg/m², waist: hip ratio 0.91 ± 0.04, serum cholesterol 5.2 ± 0.6 mmol/L, triglycerides 1.08 ± 0.53 mmol/L and high-density lipoprotein-cholesterol 1.24 ± 0.31 mmol/L. Daily dietary intake was as follows: total fat 76 ± 26 g, carbohydrate 238 ± 67 g, protein 103 ± 33 g and alcohol 20 ± 16 g. 3. The kinetics of VLDL ApoB were studied using a primed, constant infusion (1 mg/kg per h) of l-[¹³C]-leucine over 8 h with measurement of isotopic enrichment of ApoB using gas chroma-tography/mass spectrometry. The fractional turnover rate of VLDL ApoB was estimated using a monoexponential function. The mean (± SD) absolute hepatic secretion rate (ASR) of ApoB was 8.5 ± 4.6 mg/kg per day and the fractional catabolic rate (FCR) was 7.9 ± 5.6 pools/day. The ASR was significantly correlated with the waist: hip ratio (r= 0.60; P= 0.04), but not with age, BMI, weight or nutrient intake. The FCR was significantly and inversely correlated with plasma triglycerides (r =—0.53; P= 0.03) and alcohol intake (r = -0.48; P= 0.05). 4. In conclusion, the hepatic secretion of VLDL ApoB in non-obese, healthy men is primarily determined by the waist: hip ratio, a measure of visceral fat. This is consistent with the hypothesis that the rate of lipid substrate supply to the liver regulates the output of ApoB. The fractional catabolism of VLDL ApoB may, however, be inversely related to alcohol intake and appears to determine the plasma concentration of triglycerides.     

Production of both IFN-gamma and IL-5 by Onchocerca volvulus S1 antigen- specific CD4+ T cells from putatively immune individuals

Protective immunity to the parasitic nematode Onchocerca volvulus (Ov) appears to be directed against molecules of invading L3 larvae. In this study, the cellular immune reaction to such an Ov L3 protein (S1) which is protective in an animal model was analyzed using peripheral blood mononuclear cells (PBMC) of individuals from a hyperendemic area in West Africa who were exposed to Ov but remained free from disease ('putatively immune individuals'). Despite seronegativity of these individuals against S1, proliferation of PBMC was inducible, allowing generation of an S1-specific T cell line which produced IFN-gamma upon stimulation with both Ov lysate and S1. However, S1 induced significantly more IL-5 than Ov lysate. S1-specific, DQ6 (DQA1*0103/DQB1*0603)-restricted T cell clones were generated which reacted against synthetic peptides comprising amino acids 99-111 of S1. These clones, which are the first generated against a recombinant fllarial antigen, produced both IFN-gamma and IL-5 as well as little IL- 4, suggestive of a Th0-like phenotype. In conclusion, in putative immunity, reactivity against a particular parasite protein can be detectable on the level of T but not B cells. Induction of both IFN- gamma and IL-5 by S1 suggests that it may trigger macrophage plus eosinophil dependent killing of L3 in vivo. The identification of a likely DQ6 (DQA1*0103/DQB1*0603)-restricted T cell epitope may be of more general relevance, given that allele combinations of DQ6, including DQA1*0103/DQB1*0603, are negatively associated with diabetes mellitus.      

Preparation of anticipatory postural adjustments prior to stepping

Step initiation involves anticipatory postural adjustments (APAs) that propel the body mass forward and laterally before the first step. This study used a startle-like acoustic stimulus (SAS) and transcranial magnetic stimulation (TMS) to examine the preparation of APAs before forward stepping. After an instructed delay period, subjects initiated forward steps in reaction to a visual "go" cue. TMS or SAS was delivered before (-1,400 or -100 ms), on (0 ms), or after (+100 ms for TMS, +200 ms for SAS) the imperative "go" cue. Ground reaction forces and electromyographic activity were recorded. In control trials, the mean reaction time was 217 +/- 38 ms. In contrast, the SAS evoked APAs that had an average onset of 110 +/- 54 ms, whereas the incidence, magnitude, and duration of the APA increased as the stimulus timing approached the "go" cue. A facilitation of motor-evoked potentials in the initial agonist muscle was observed only when TMS was applied at +100 ms. These findings indicate that there was an initial phase of movement preparation during which the APA-stepping sequence was progressively assembled, and that this early preparation did not involve the corticomotor pathways activated by TMS. The subsequent increase in corticomotor excitability between the imperative stimulus and onset of the APA suggests that corticospinal pathways contribute to the voluntary initiation of the prepared APA-stepping sequence. These findings are consistent with a feedforward mode of neural control whereby the motor sequence, including the associated postural adjustments, is prepared before voluntary movement.     

Identical nucleotide sequences of the 3'A gamma globin gene enhancer elements from four different chromosomes

We have determined the nucleotide sequence of the 2,360-bp long EcoRI fragment from four chromosomes; this fragment is located 3' to the A gamma globin gene and is considered to contain the enhancer element identified by Bodine and Ley. The chromosomes were from an Arabian sickle cell anemia patient with high Hb F and a homozygosity for haplotype No 31 and from a black sickle cell anemia patient with low Hb F and a homozygosity for haplotype No 19. A third chromosome carried the determinant for a nondeletional hereditary persistence of fetal hemoglobin seen in a Chinese subject, and the fourth was a normal chromosome from a Yugoslavian subject. Twenty-one differences were observed when a comparison was made with the published sequence; no differences were seen between the sequences of the four different samples except for an additional mutation in the Chinese. These data make it unlikely that specific mutations within this sequence are associated with increases in G gamma and A gamma production.     

Death in CHARGE syndrome after the neonatal period

Bergman JEH, Blake KD, Bakker MK, du Marchie Sarvaas GJ, Free RH, van Ravenswaaij‐Arts CMA. Death in CHARGE syndrome after the neonatal period. CHARGE syndrome is a multiple congenital anomaly syndrome that can be life‐threatening in the neonatal period. Complex heart defects, bilateral choanal atresia, esophageal atresia, severe T‐cell deficiency, and brain anomalies can cause neonatal death. As little is known about the causes of death in childhood and adolescence, we studied post‐neonatal death in patients with CHARGE syndrome. We collected medical data on three deceased children from a follow‐up cohort of 48 CHARGE patients and retrospectively on an additional four deceased patients (age at death 11 months to 22 years). We analyzed the factors that had contributed to their death. In five patients respiratory aspiration had most likely contributed to premature death, one died of post‐operative complications, and another choked during eating. From our findings and a literature review, we suggest that swallowing problems, gastro‐esophageal reflux disease, respiratory aspiration and post‐operative airway events are important contributors to post‐neonatal death in CHARGE syndrome. Cranial nerve dysfunction is proposed as the underlying pathogenic mechanism. We recommend every CHARGE patient with feeding difficulties to be assessed by a multidisciplinary team to evaluate cranial nerve function and swallowing. Timely treatment of swallowing problems and gastro‐esophageal reflux disease is important. Surgical procedures on these patients should be combined whenever possible because of their increased risk of post‐operative complications and intubation problems. Finally, we recommend performing autopsy in deceased CHARGE patients in order to gain more insight into causes of death.