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ABSTRACT: The barrier functions of the stratum corneum and the epidermal layers present a tremendous challenge in achieving effective transdermal delivery of drug molecules. Although a few reports have shown that poly(amidoamine) (PAMAM) dendrimers are effective skin-penetration enhancers, little is known regarding the fundamental mechanisms behind the dendrimer-skin interactions. In this Article, we have performed a systematic study to better elucidate how dendrimers interact with skin layers depending on their size and surface groups. Franz diffusion cells and confocal microscopy were employed to observe dendrimer interactions with full-thickness porcine skin samples. We have found that smaller PAMAM dendrimers (generation 2 (G2)) penetrate the skin layers more efficiently than the larger ones (G4). We have also found that G2 PAMAM dendrimers that are surface-modified by either acetylation or carboxylation exhibit increased skin permeation and likely diffuse through an extracellular pathway. In contrast, amine-terminated dendrimers show enhanced cell internalization and skin retention but reduced skin permeation. In addition, conjugation of oleic acid to G2 dendrimers increases their 1-octanol/PBS partition coefficient, resulting in increased skin absorption and retention. Here we report that size, surface charge, and hydrophobicity directly dictate the permeation route and efficiency of dendrimer translocation across the skin layers, providing a design guideline for engineering PAMAM dendrimers as a potential transdermal delivery vector.
Biomacromolecules 05/2012; 13(7):2154-62. · 5.48 Impact Factor
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ABSTRACT: In this work, the controlled fabrication of highly ordered ZnO nanowire (NW) arrays on silicon substrates is reported. Si NWs fabricated by a combination of phase shift lithography and etching are used as a template and are subsequently substituted by ZnO NWs with a dry-etching technique and atomic layer deposition. This fabrication technique allows the vertical ZnO NWs to be fabricated on 4 in Si wafers. Room temperature photoluminescence and micro-photoluminescence are used to observe the optical properties of the atomic layer deposition (ALD) based ZnO NWs. The sharp UV luminescence observed from the ALD ZnO NWs is unexpected for the polycrystalline nanostructure. Surprisingly, the defect related luminescence is much decreased compared to an ALD ZnO film deposited at the same time ona plane substrate. Electrical characterization was carried out by using nanomanipulators. With the p-type Si substrate and the n-type ZnO NWs the nanodevices represent p–n NW diodes.The nanowire diodes show a very high breakthrough potential which implies that the ALD ZnO NWs can be used for future electronic applications.
Nanotechnology 05/2012; 23(23):235607. · 3.98 Impact Factor
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ABSTRACT: Pulmonary vein thrombosis is a rare disease and is usually represented as a complication of atrial fibrillation, pulmonary tumors, and lobectomy. Although it is a potentially life threatening condition, the venous disease is easy to misdiagnose because of the non-specific symptoms. In this article, we present a 30-year-old patient who suffered from pulmonary vein thrombosis without any causes. He was diagnosed with other pulmonary disorders till the thrombus within the pulmonary vein extended into the left atrium. Left atrium mass resection and a left lower lobectomy were undertaken with relative urgency. The postoperative course was uneventful. The patient received a long course of oral anticoagulant therapy.
Chinese medical journal 03/2012; 125(6):1197-200. · 0.86 Impact Factor
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ABSTRACT: A case-control study of 538 individuals investigated whether the angiotensinogen gene (AGT) might be implicated in the pathogenesis of essential hypertension in the Hani and Yi populations of China. Genotypes for two diallelic DNA polymorphisms observed at amino acid residues 174 (T174M) and 235 (M235T) within the coding sequence were determined. M235T and T174M genotyping with PCR-RFLP was performed in 267 normotensive subjects and 271 hypertensive subjects. No significant difference was found between normotensives and hypertensives in genotype distribution and allele frequency for either M235T or T174M in the Hani or the Yi populations (P > 0.05). Relative to carriers of the 235T/235T and 174T/174T combination, the others had a significantly elevated risk of hypertension (OR = 1.62, 95% CI 1.02-2.59; P = 0.043) in the Hani population. The AGT M235T and T174M variants in combination may play a role in the genetic predisposition to develop essential hypertension in the Hani minority of China.
Biochemical Genetics 04/2009; 47(5-6):344-50. · 0.86 Impact Factor
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ABSTRACT: Endothelial nitric oxide synthase (eNOS) plays an important role in maintaining blood pressure homeostasis and vascular integrity. Recently, a G894T polymorphism in exon 7 of the eNOS gene has been reported to be associated with high blood pressure. We investigated the association between this polymorphism and essential hypertension (EH) in Hani (n=305 individuals) and Yi (n=233 individuals) minorities of China.
eNOS genotyping with polymerase chain reaction-restriction fragment length polymorphism was performed in 267 normotensive (NT) subjects and 271 EH subjects.
The frequencies of eNOS G894T genotypes in NT controls and EH cohort in Hani population were GG: 0.714 vs. 0.581; GT+TT: 0.286 vs. 0.419, respectively. The frequencies of eNOS G894T genotypes in NT controls and EH cohort in Yi population were GG: 0.552 vs. 0.717; GT+TT: 0.448 vs. 0.283, respectively. There was a significant difference in G894T genotype distribution between NTs and hypertensives in both Hani and Yi populations (p<0.05).
The present study suggested an association between a G894T polymorphism of eNOS gene and EH in Hani and Yi minority groups of China.
Archives of Medical Research 02/2008; 39(2):222-5. · 1.88 Impact Factor
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Clinica Chimica Acta 01/2007; 374(1-2):153-4. · 2.54 Impact Factor
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Journal of Hypertension 11/2006; 24(12):2474-2476. · 4.02 Impact Factor
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ABSTRACT: The human beta2-adrenergic receptor (ADRB2) gene is a candidate for contributing to the pathophysiology of essential hypertension. The aims of the present study were to investigate the associations of differing single nucleotide polymorphisms (SNPs) and haplotypes of the ADRB2 gene promoter and coding regions with essential hypertension in genetically homogeneous Hani and Yi minority groups that are non-Han Chinese.
Four SNPs in the regulatory and seven SNPs in the coding region were genotyped in 271 essential hypertension individuals and 267 controls, and eight haplotypes in the regulatory and five haplotypes in the coding region were determined and tested for association using the likelihood test statistic.
There were significant associations of essential hypertension with separate SNPs located in both the regulatory and coding regions in the Yi minority group. In contrast, no associations of essential hypertension were detected with any of single SNPs in the Hani minority group. There is a significant difference in haplotype frequency distributions between the hypertensive participants and the controls in two groups (P < 10).
The results indicate that variants at the ADRB2 locus may play a role in the pathophysiology of hypertension specifically in the Yi minority group.
Journal of Hypertension 06/2006; 24(6):1041-7. · 4.02 Impact Factor
